| This is gdb.info, produced by makeinfo version 4.13 from ./gdb.texinfo. |
| |
| INFO-DIR-SECTION Software development |
| START-INFO-DIR-ENTRY |
| * Gdb: (gdb). The GNU debugger. |
| * gdbserver: (gdb) Server. The GNU debugging server. |
| END-INFO-DIR-ENTRY |
| |
| Copyright (C) 1988-2013 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being "Free Software" and "Free Software Needs Free |
| Documentation", with the Front-Cover Texts being "A GNU Manual," and |
| with the Back-Cover Texts as in (a) below. |
| |
| (a) The FSF's Back-Cover Text is: "You are free to copy and modify |
| this GNU Manual. Buying copies from GNU Press supports the FSF in |
| developing GNU and promoting software freedom." |
| |
| This file documents the GNU debugger GDB. |
| |
| This is the Tenth Edition, of `Debugging with GDB: the GNU |
| Source-Level Debugger' for GDB (GDB) Version 7.6.50.20131211-cvs. |
| |
| Copyright (C) 1988-2013 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being "Free Software" and "Free Software Needs Free |
| Documentation", with the Front-Cover Texts being "A GNU Manual," and |
| with the Back-Cover Texts as in (a) below. |
| |
| (a) The FSF's Back-Cover Text is: "You are free to copy and modify |
| this GNU Manual. Buying copies from GNU Press supports the FSF in |
| developing GNU and promoting software freedom." |
| |
| |
| File: gdb.info, Node: GDB/MI Miscellaneous Commands, Prev: GDB/MI Ada Exceptions Commands, Up: GDB/MI |
| |
| 27.23 Miscellaneous GDB/MI Commands |
| =================================== |
| |
| The `-gdb-exit' Command |
| ----------------------- |
| |
| Synopsis |
| ........ |
| |
| -gdb-exit |
| |
| Exit GDB immediately. |
| |
| GDB Command |
| ........... |
| |
| Approximately corresponds to `quit'. |
| |
| Example |
| ....... |
| |
| (gdb) |
| -gdb-exit |
| ^exit |
| |
| The `-gdb-set' Command |
| ---------------------- |
| |
| Synopsis |
| ........ |
| |
| -gdb-set |
| |
| Set an internal GDB variable. |
| |
| GDB Command |
| ........... |
| |
| The corresponding GDB command is `set'. |
| |
| Example |
| ....... |
| |
| (gdb) |
| -gdb-set $foo=3 |
| ^done |
| (gdb) |
| |
| The `-gdb-show' Command |
| ----------------------- |
| |
| Synopsis |
| ........ |
| |
| -gdb-show |
| |
| Show the current value of a GDB variable. |
| |
| GDB Command |
| ........... |
| |
| The corresponding GDB command is `show'. |
| |
| Example |
| ....... |
| |
| (gdb) |
| -gdb-show annotate |
| ^done,value="0" |
| (gdb) |
| |
| The `-gdb-version' Command |
| -------------------------- |
| |
| Synopsis |
| ........ |
| |
| -gdb-version |
| |
| Show version information for GDB. Used mostly in testing. |
| |
| GDB Command |
| ........... |
| |
| The GDB equivalent is `show version'. GDB by default shows this |
| information when you start an interactive session. |
| |
| Example |
| ....... |
| |
| (gdb) |
| -gdb-version |
| ~GNU gdb 5.2.1 |
| ~Copyright 2000 Free Software Foundation, Inc. |
| ~GDB is free software, covered by the GNU General Public License, and |
| ~you are welcome to change it and/or distribute copies of it under |
| ~ certain conditions. |
| ~Type "show copying" to see the conditions. |
| ~There is absolutely no warranty for GDB. Type "show warranty" for |
| ~ details. |
| ~This GDB was configured as |
| "--host=sparc-sun-solaris2.5.1 --target=ppc-eabi". |
| ^done |
| (gdb) |
| |
| The `-info-gdb-mi-command' Command |
| ---------------------------------- |
| |
| Synopsis |
| ........ |
| |
| -info-gdb-mi-command CMD_NAME |
| |
| Query support for the GDB/MI command named CMD_NAME. |
| |
| Note that the dash (`-') starting all GDB/MI commands is technically |
| not part of the command name (*note GDB/MI Input Syntax::), and thus |
| should be omitted in CMD_NAME. However, for ease of use, this command |
| also accepts the form with the leading dash. |
| |
| GDB Command |
| ........... |
| |
| There is no corresponding GDB command. |
| |
| Result |
| ...... |
| |
| The result is a tuple. There is currently only one field: |
| |
| `exists' |
| This field is equal to `"true"' if the GDB/MI command exists, |
| `"false"' otherwise. |
| |
| |
| Example |
| ....... |
| |
| Here is an example where the GDB/MI command does not exist: |
| |
| -info-gdb-mi-command unsupported-command |
| ^done,command={exists="false"} |
| |
| And here is an example where the GDB/MI command is known to the |
| debugger: |
| |
| -info-gdb-mi-command symbol-list-lines |
| ^done,command={exists="true"} |
| |
| The `-list-features' Command |
| ---------------------------- |
| |
| Returns a list of particular features of the MI protocol that this |
| version of gdb implements. A feature can be a command, or a new field |
| in an output of some command, or even an important bugfix. While a |
| frontend can sometimes detect presence of a feature at runtime, it is |
| easier to perform detection at debugger startup. |
| |
| The command returns a list of strings, with each string naming an |
| available feature. Each returned string is just a name, it does not |
| have any internal structure. The list of possible feature names is |
| given below. |
| |
| Example output: |
| |
| (gdb) -list-features |
| ^done,result=["feature1","feature2"] |
| |
| The current list of features is: |
| |
| `frozen-varobjs' |
| Indicates support for the `-var-set-frozen' command, as well as |
| possible presense of the `frozen' field in the output of |
| `-varobj-create'. |
| |
| `pending-breakpoints' |
| Indicates support for the `-f' option to the `-break-insert' |
| command. |
| |
| `python' |
| Indicates Python scripting support, Python-based pretty-printing |
| commands, and possible presence of the `display_hint' field in the |
| output of `-var-list-children' |
| |
| `thread-info' |
| Indicates support for the `-thread-info' command. |
| |
| `data-read-memory-bytes' |
| Indicates support for the `-data-read-memory-bytes' and the |
| `-data-write-memory-bytes' commands. |
| |
| `breakpoint-notifications' |
| Indicates that changes to breakpoints and breakpoints created via |
| the CLI will be announced via async records. |
| |
| `ada-task-info' |
| Indicates support for the `-ada-task-info' command. |
| |
| `language-option' |
| Indicates that all GDB/MI commands accept the `--language' option |
| (*note Context management::). |
| |
| `info-gdb-mi-command' |
| Indicates support for the `-info-gdb-mi-command' command. |
| |
| `undefined-command-error-code' |
| Indicates support for the "undefined-command" error code in error |
| result records, produced when trying to execute an undefined |
| GDB/MI command (*note GDB/MI Result Records::). |
| |
| `exec-run-start-option' |
| Indicates that the `-exec-run' command supports the `--start' |
| option (*note GDB/MI Program Execution::). |
| |
| The `-list-target-features' Command |
| ----------------------------------- |
| |
| Returns a list of particular features that are supported by the target. |
| Those features affect the permitted MI commands, but unlike the |
| features reported by the `-list-features' command, the features depend |
| on which target GDB is using at the moment. Whenever a target can |
| change, due to commands such as `-target-select', `-target-attach' or |
| `-exec-run', the list of target features may change, and the frontend |
| should obtain it again. Example output: |
| |
| (gdb) -list-target-features |
| ^done,result=["async"] |
| |
| The current list of features is: |
| |
| `async' |
| Indicates that the target is capable of asynchronous command |
| execution, which means that GDB will accept further commands while |
| the target is running. |
| |
| `reverse' |
| Indicates that the target is capable of reverse execution. *Note |
| Reverse Execution::, for more information. |
| |
| |
| The `-list-thread-groups' Command |
| --------------------------------- |
| |
| Synopsis |
| -------- |
| |
| -list-thread-groups [ --available ] [ --recurse 1 ] [ GROUP ... ] |
| |
| Lists thread groups (*note Thread groups::). When a single thread |
| group is passed as the argument, lists the children of that group. |
| When several thread group are passed, lists information about those |
| thread groups. Without any parameters, lists information about all |
| top-level thread groups. |
| |
| Normally, thread groups that are being debugged are reported. With |
| the `--available' option, GDB reports thread groups available on the |
| target. |
| |
| The output of this command may have either a `threads' result or a |
| `groups' result. The `thread' result has a list of tuples as value, |
| with each tuple describing a thread (*note GDB/MI Thread |
| Information::). The `groups' result has a list of tuples as value, |
| each tuple describing a thread group. If top-level groups are |
| requested (that is, no parameter is passed), or when several groups are |
| passed, the output always has a `groups' result. The format of the |
| `group' result is described below. |
| |
| To reduce the number of roundtrips it's possible to list thread |
| groups together with their children, by passing the `--recurse' option |
| and the recursion depth. Presently, only recursion depth of 1 is |
| permitted. If this option is present, then every reported thread group |
| will also include its children, either as `group' or `threads' field. |
| |
| In general, any combination of option and parameters is permitted, |
| with the following caveats: |
| |
| * When a single thread group is passed, the output will typically be |
| the `threads' result. Because threads may not contain anything, |
| the `recurse' option will be ignored. |
| |
| * When the `--available' option is passed, limited information may |
| be available. In particular, the list of threads of a process |
| might be inaccessible. Further, specifying specific thread groups |
| might not give any performance advantage over listing all thread |
| groups. The frontend should assume that `-list-thread-groups |
| --available' is always an expensive operation and cache the |
| results. |
| |
| |
| The `groups' result is a list of tuples, where each tuple may have |
| the following fields: |
| |
| `id' |
| Identifier of the thread group. This field is always present. |
| The identifier is an opaque string; frontends should not try to |
| convert it to an integer, even though it might look like one. |
| |
| `type' |
| The type of the thread group. At present, only `process' is a |
| valid type. |
| |
| `pid' |
| The target-specific process identifier. This field is only present |
| for thread groups of type `process' and only if the process exists. |
| |
| `num_children' |
| The number of children this thread group has. This field may be |
| absent for an available thread group. |
| |
| `threads' |
| This field has a list of tuples as value, each tuple describing a |
| thread. It may be present if the `--recurse' option is specified, |
| and it's actually possible to obtain the threads. |
| |
| `cores' |
| This field is a list of integers, each identifying a core that one |
| thread of the group is running on. This field may be absent if |
| such information is not available. |
| |
| `executable' |
| The name of the executable file that corresponds to this thread |
| group. The field is only present for thread groups of type |
| `process', and only if there is a corresponding executable file. |
| |
| |
| Example |
| ------- |
| |
| gdb |
| -list-thread-groups |
| ^done,groups=[{id="17",type="process",pid="yyy",num_children="2"}] |
| -list-thread-groups 17 |
| ^done,threads=[{id="2",target-id="Thread 0xb7e14b90 (LWP 21257)", |
| frame={level="0",addr="0xffffe410",func="__kernel_vsyscall",args=[]},state="running"}, |
| {id="1",target-id="Thread 0xb7e156b0 (LWP 21254)", |
| frame={level="0",addr="0x0804891f",func="foo",args=[{name="i",value="10"}], |
| file="/tmp/a.c",fullname="/tmp/a.c",line="158"},state="running"}]] |
| -list-thread-groups --available |
| ^done,groups=[{id="17",type="process",pid="yyy",num_children="2",cores=[1,2]}] |
| -list-thread-groups --available --recurse 1 |
| ^done,groups=[{id="17", types="process",pid="yyy",num_children="2",cores=[1,2], |
| threads=[{id="1",target-id="Thread 0xb7e14b90",cores=[1]}, |
| {id="2",target-id="Thread 0xb7e14b90",cores=[2]}]},..] |
| -list-thread-groups --available --recurse 1 17 18 |
| ^done,groups=[{id="17", types="process",pid="yyy",num_children="2",cores=[1,2], |
| threads=[{id="1",target-id="Thread 0xb7e14b90",cores=[1]}, |
| {id="2",target-id="Thread 0xb7e14b90",cores=[2]}]},...] |
| |
| The `-info-os' Command |
| ---------------------- |
| |
| Synopsis |
| ........ |
| |
| -info-os [ TYPE ] |
| |
| If no argument is supplied, the command returns a table of available |
| operating-system-specific information types. If one of these types is |
| supplied as an argument TYPE, then the command returns a table of data |
| of that type. |
| |
| The types of information available depend on the target operating |
| system. |
| |
| GDB Command |
| ........... |
| |
| The corresponding GDB command is `info os'. |
| |
| Example |
| ....... |
| |
| When run on a GNU/Linux system, the output will look something like |
| this: |
| |
| gdb |
| -info-os |
| ^done,OSDataTable={nr_rows="9",nr_cols="3", |
| hdr=[{width="10",alignment="-1",col_name="col0",colhdr="Type"}, |
| {width="10",alignment="-1",col_name="col1",colhdr="Description"}, |
| {width="10",alignment="-1",col_name="col2",colhdr="Title"}], |
| body=[item={col0="processes",col1="Listing of all processes", |
| col2="Processes"}, |
| item={col0="procgroups",col1="Listing of all process groups", |
| col2="Process groups"}, |
| item={col0="threads",col1="Listing of all threads", |
| col2="Threads"}, |
| item={col0="files",col1="Listing of all file descriptors", |
| col2="File descriptors"}, |
| item={col0="sockets",col1="Listing of all internet-domain sockets", |
| col2="Sockets"}, |
| item={col0="shm",col1="Listing of all shared-memory regions", |
| col2="Shared-memory regions"}, |
| item={col0="semaphores",col1="Listing of all semaphores", |
| col2="Semaphores"}, |
| item={col0="msg",col1="Listing of all message queues", |
| col2="Message queues"}, |
| item={col0="modules",col1="Listing of all loaded kernel modules", |
| col2="Kernel modules"}]} |
| gdb |
| -info-os processes |
| ^done,OSDataTable={nr_rows="190",nr_cols="4", |
| hdr=[{width="10",alignment="-1",col_name="col0",colhdr="pid"}, |
| {width="10",alignment="-1",col_name="col1",colhdr="user"}, |
| {width="10",alignment="-1",col_name="col2",colhdr="command"}, |
| {width="10",alignment="-1",col_name="col3",colhdr="cores"}], |
| body=[item={col0="1",col1="root",col2="/sbin/init",col3="0"}, |
| item={col0="2",col1="root",col2="[kthreadd]",col3="1"}, |
| item={col0="3",col1="root",col2="[ksoftirqd/0]",col3="0"}, |
| ... |
| item={col0="26446",col1="stan",col2="bash",col3="0"}, |
| item={col0="28152",col1="stan",col2="bash",col3="1"}]} |
| (gdb) |
| |
| (Note that the MI output here includes a `"Title"' column that does |
| not appear in command-line `info os'; this column is useful for MI |
| clients that want to enumerate the types of data, such as in a popup |
| menu, but is needless clutter on the command line, and `info os' omits |
| it.) |
| |
| The `-add-inferior' Command |
| --------------------------- |
| |
| Synopsis |
| -------- |
| |
| -add-inferior |
| |
| Creates a new inferior (*note Inferiors and Programs::). The created |
| inferior is not associated with any executable. Such association may |
| be established with the `-file-exec-and-symbols' command (*note GDB/MI |
| File Commands::). The command response has a single field, `inferior', |
| whose value is the identifier of the thread group corresponding to the |
| new inferior. |
| |
| Example |
| ------- |
| |
| gdb |
| -add-inferior |
| ^done,inferior="i3" |
| |
| The `-interpreter-exec' Command |
| ------------------------------- |
| |
| Synopsis |
| -------- |
| |
| -interpreter-exec INTERPRETER COMMAND |
| Execute the specified COMMAND in the given INTERPRETER. |
| |
| GDB Command |
| ----------- |
| |
| The corresponding GDB command is `interpreter-exec'. |
| |
| Example |
| ------- |
| |
| (gdb) |
| -interpreter-exec console "break main" |
| &"During symbol reading, couldn't parse type; debugger out of date?.\n" |
| &"During symbol reading, bad structure-type format.\n" |
| ~"Breakpoint 1 at 0x8074fc6: file ../../src/gdb/main.c, line 743.\n" |
| ^done |
| (gdb) |
| |
| The `-inferior-tty-set' Command |
| ------------------------------- |
| |
| Synopsis |
| -------- |
| |
| -inferior-tty-set /dev/pts/1 |
| |
| Set terminal for future runs of the program being debugged. |
| |
| GDB Command |
| ----------- |
| |
| The corresponding GDB command is `set inferior-tty' /dev/pts/1. |
| |
| Example |
| ------- |
| |
| (gdb) |
| -inferior-tty-set /dev/pts/1 |
| ^done |
| (gdb) |
| |
| The `-inferior-tty-show' Command |
| -------------------------------- |
| |
| Synopsis |
| -------- |
| |
| -inferior-tty-show |
| |
| Show terminal for future runs of program being debugged. |
| |
| GDB Command |
| ----------- |
| |
| The corresponding GDB command is `show inferior-tty'. |
| |
| Example |
| ------- |
| |
| (gdb) |
| -inferior-tty-set /dev/pts/1 |
| ^done |
| (gdb) |
| -inferior-tty-show |
| ^done,inferior_tty_terminal="/dev/pts/1" |
| (gdb) |
| |
| The `-enable-timings' Command |
| ----------------------------- |
| |
| Synopsis |
| -------- |
| |
| -enable-timings [yes | no] |
| |
| Toggle the printing of the wallclock, user and system times for an MI |
| command as a field in its output. This command is to help frontend |
| developers optimize the performance of their code. No argument is |
| equivalent to `yes'. |
| |
| GDB Command |
| ----------- |
| |
| No equivalent. |
| |
| Example |
| ------- |
| |
| (gdb) |
| -enable-timings |
| ^done |
| (gdb) |
| -break-insert main |
| ^done,bkpt={number="1",type="breakpoint",disp="keep",enabled="y", |
| addr="0x080484ed",func="main",file="myprog.c", |
| fullname="/home/nickrob/myprog.c",line="73",thread-groups=["i1"], |
| times="0"}, |
| time={wallclock="0.05185",user="0.00800",system="0.00000"} |
| (gdb) |
| -enable-timings no |
| ^done |
| (gdb) |
| -exec-run |
| ^running |
| (gdb) |
| *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",thread-id="0", |
| frame={addr="0x080484ed",func="main",args=[{name="argc",value="1"}, |
| {name="argv",value="0xbfb60364"}],file="myprog.c", |
| fullname="/home/nickrob/myprog.c",line="73"} |
| (gdb) |
| |
| |
| File: gdb.info, Node: Annotations, Next: JIT Interface, Prev: GDB/MI, Up: Top |
| |
| 28 GDB Annotations |
| ****************** |
| |
| This chapter describes annotations in GDB. Annotations were designed |
| to interface GDB to graphical user interfaces or other similar programs |
| which want to interact with GDB at a relatively high level. |
| |
| The annotation mechanism has largely been superseded by GDB/MI |
| (*note GDB/MI::). |
| |
| * Menu: |
| |
| * Annotations Overview:: What annotations are; the general syntax. |
| * Server Prefix:: Issuing a command without affecting user state. |
| * Prompting:: Annotations marking GDB's need for input. |
| * Errors:: Annotations for error messages. |
| * Invalidation:: Some annotations describe things now invalid. |
| * Annotations for Running:: |
| Whether the program is running, how it stopped, etc. |
| * Source Annotations:: Annotations describing source code. |
| |
| |
| File: gdb.info, Node: Annotations Overview, Next: Server Prefix, Up: Annotations |
| |
| 28.1 What is an Annotation? |
| =========================== |
| |
| Annotations start with a newline character, two `control-z' characters, |
| and the name of the annotation. If there is no additional information |
| associated with this annotation, the name of the annotation is followed |
| immediately by a newline. If there is additional information, the name |
| of the annotation is followed by a space, the additional information, |
| and a newline. The additional information cannot contain newline |
| characters. |
| |
| Any output not beginning with a newline and two `control-z' |
| characters denotes literal output from GDB. Currently there is no need |
| for GDB to output a newline followed by two `control-z' characters, but |
| if there was such a need, the annotations could be extended with an |
| `escape' annotation which means those three characters as output. |
| |
| The annotation LEVEL, which is specified using the `--annotate' |
| command line option (*note Mode Options::), controls how much |
| information GDB prints together with its prompt, values of expressions, |
| source lines, and other types of output. Level 0 is for no |
| annotations, level 1 is for use when GDB is run as a subprocess of GNU |
| Emacs, level 3 is the maximum annotation suitable for programs that |
| control GDB, and level 2 annotations have been made obsolete (*note |
| Limitations of the Annotation Interface: (annotate)Limitations.). |
| |
| `set annotate LEVEL' |
| The GDB command `set annotate' sets the level of annotations to |
| the specified LEVEL. |
| |
| `show annotate' |
| Show the current annotation level. |
| |
| This chapter describes level 3 annotations. |
| |
| A simple example of starting up GDB with annotations is: |
| |
| $ gdb --annotate=3 |
| GNU gdb 6.0 |
| Copyright 2003 Free Software Foundation, Inc. |
| GDB is free software, covered by the GNU General Public License, |
| and you are welcome to change it and/or distribute copies of it |
| under certain conditions. |
| Type "show copying" to see the conditions. |
| There is absolutely no warranty for GDB. Type "show warranty" |
| for details. |
| This GDB was configured as "i386-pc-linux-gnu" |
| |
| ^Z^Zpre-prompt |
| (gdb) |
| ^Z^Zprompt |
| quit |
| |
| ^Z^Zpost-prompt |
| $ |
| |
| Here `quit' is input to GDB; the rest is output from GDB. The three |
| lines beginning `^Z^Z' (where `^Z' denotes a `control-z' character) are |
| annotations; the rest is output from GDB. |
| |
| |
| File: gdb.info, Node: Server Prefix, Next: Prompting, Prev: Annotations Overview, Up: Annotations |
| |
| 28.2 The Server Prefix |
| ====================== |
| |
| If you prefix a command with `server ' then it will not affect the |
| command history, nor will it affect GDB's notion of which command to |
| repeat if <RET> is pressed on a line by itself. This means that |
| commands can be run behind a user's back by a front-end in a |
| transparent manner. |
| |
| The `server ' prefix does not affect the recording of values into |
| the value history; to print a value without recording it into the value |
| history, use the `output' command instead of the `print' command. |
| |
| Using this prefix also disables confirmation requests (*note |
| confirmation requests::). |
| |
| |
| File: gdb.info, Node: Prompting, Next: Errors, Prev: Server Prefix, Up: Annotations |
| |
| 28.3 Annotation for GDB Input |
| ============================= |
| |
| When GDB prompts for input, it annotates this fact so it is possible to |
| know when to send output, when the output from a given command is over, |
| etc. |
| |
| Different kinds of input each have a different "input type". Each |
| input type has three annotations: a `pre-' annotation, which denotes |
| the beginning of any prompt which is being output, a plain annotation, |
| which denotes the end of the prompt, and then a `post-' annotation |
| which denotes the end of any echo which may (or may not) be associated |
| with the input. For example, the `prompt' input type features the |
| following annotations: |
| |
| ^Z^Zpre-prompt |
| ^Z^Zprompt |
| ^Z^Zpost-prompt |
| |
| The input types are |
| |
| `prompt' |
| When GDB is prompting for a command (the main GDB prompt). |
| |
| `commands' |
| When GDB prompts for a set of commands, like in the `commands' |
| command. The annotations are repeated for each command which is |
| input. |
| |
| `overload-choice' |
| When GDB wants the user to select between various overloaded |
| functions. |
| |
| `query' |
| When GDB wants the user to confirm a potentially dangerous |
| operation. |
| |
| `prompt-for-continue' |
| When GDB is asking the user to press return to continue. Note: |
| Don't expect this to work well; instead use `set height 0' to |
| disable prompting. This is because the counting of lines is buggy |
| in the presence of annotations. |
| |
| |
| File: gdb.info, Node: Errors, Next: Invalidation, Prev: Prompting, Up: Annotations |
| |
| 28.4 Errors |
| =========== |
| |
| ^Z^Zquit |
| |
| This annotation occurs right before GDB responds to an interrupt. |
| |
| ^Z^Zerror |
| |
| This annotation occurs right before GDB responds to an error. |
| |
| Quit and error annotations indicate that any annotations which GDB |
| was in the middle of may end abruptly. For example, if a |
| `value-history-begin' annotation is followed by a `error', one cannot |
| expect to receive the matching `value-history-end'. One cannot expect |
| not to receive it either, however; an error annotation does not |
| necessarily mean that GDB is immediately returning all the way to the |
| top level. |
| |
| A quit or error annotation may be preceded by |
| |
| ^Z^Zerror-begin |
| |
| Any output between that and the quit or error annotation is the error |
| message. |
| |
| Warning messages are not yet annotated. |
| |
| |
| File: gdb.info, Node: Invalidation, Next: Annotations for Running, Prev: Errors, Up: Annotations |
| |
| 28.5 Invalidation Notices |
| ========================= |
| |
| The following annotations say that certain pieces of state may have |
| changed. |
| |
| `^Z^Zframes-invalid' |
| The frames (for example, output from the `backtrace' command) may |
| have changed. |
| |
| `^Z^Zbreakpoints-invalid' |
| The breakpoints may have changed. For example, the user just |
| added or deleted a breakpoint. |
| |
| |
| File: gdb.info, Node: Annotations for Running, Next: Source Annotations, Prev: Invalidation, Up: Annotations |
| |
| 28.6 Running the Program |
| ======================== |
| |
| When the program starts executing due to a GDB command such as `step' |
| or `continue', |
| |
| ^Z^Zstarting |
| |
| is output. When the program stops, |
| |
| ^Z^Zstopped |
| |
| is output. Before the `stopped' annotation, a variety of |
| annotations describe how the program stopped. |
| |
| `^Z^Zexited EXIT-STATUS' |
| The program exited, and EXIT-STATUS is the exit status (zero for |
| successful exit, otherwise nonzero). |
| |
| `^Z^Zsignalled' |
| The program exited with a signal. After the `^Z^Zsignalled', the |
| annotation continues: |
| |
| INTRO-TEXT |
| ^Z^Zsignal-name |
| NAME |
| ^Z^Zsignal-name-end |
| MIDDLE-TEXT |
| ^Z^Zsignal-string |
| STRING |
| ^Z^Zsignal-string-end |
| END-TEXT |
| |
| where NAME is the name of the signal, such as `SIGILL' or |
| `SIGSEGV', and STRING is the explanation of the signal, such as |
| `Illegal Instruction' or `Segmentation fault'. INTRO-TEXT, |
| MIDDLE-TEXT, and END-TEXT are for the user's benefit and have no |
| particular format. |
| |
| `^Z^Zsignal' |
| The syntax of this annotation is just like `signalled', but GDB is |
| just saying that the program received the signal, not that it was |
| terminated with it. |
| |
| `^Z^Zbreakpoint NUMBER' |
| The program hit breakpoint number NUMBER. |
| |
| `^Z^Zwatchpoint NUMBER' |
| The program hit watchpoint number NUMBER. |
| |
| |
| File: gdb.info, Node: Source Annotations, Prev: Annotations for Running, Up: Annotations |
| |
| 28.7 Displaying Source |
| ====================== |
| |
| The following annotation is used instead of displaying source code: |
| |
| ^Z^Zsource FILENAME:LINE:CHARACTER:MIDDLE:ADDR |
| |
| where FILENAME is an absolute file name indicating which source |
| file, LINE is the line number within that file (where 1 is the first |
| line in the file), CHARACTER is the character position within the file |
| (where 0 is the first character in the file) (for most debug formats |
| this will necessarily point to the beginning of a line), MIDDLE is |
| `middle' if ADDR is in the middle of the line, or `beg' if ADDR is at |
| the beginning of the line, and ADDR is the address in the target |
| program associated with the source which is being displayed. ADDR is |
| in the form `0x' followed by one or more lowercase hex digits (note |
| that this does not depend on the language). |
| |
| |
| File: gdb.info, Node: JIT Interface, Next: In-Process Agent, Prev: Annotations, Up: Top |
| |
| 29 JIT Compilation Interface |
| **************************** |
| |
| This chapter documents GDB's "just-in-time" (JIT) compilation |
| interface. A JIT compiler is a program or library that generates native |
| executable code at runtime and executes it, usually in order to achieve |
| good performance while maintaining platform independence. |
| |
| Programs that use JIT compilation are normally difficult to debug |
| because portions of their code are generated at runtime, instead of |
| being loaded from object files, which is where GDB normally finds the |
| program's symbols and debug information. In order to debug programs |
| that use JIT compilation, GDB has an interface that allows the program |
| to register in-memory symbol files with GDB at runtime. |
| |
| If you are using GDB to debug a program that uses this interface, |
| then it should work transparently so long as you have not stripped the |
| binary. If you are developing a JIT compiler, then the interface is |
| documented in the rest of this chapter. At this time, the only known |
| client of this interface is the LLVM JIT. |
| |
| Broadly speaking, the JIT interface mirrors the dynamic loader |
| interface. The JIT compiler communicates with GDB by writing data into |
| a global variable and calling a fuction at a well-known symbol. When |
| GDB attaches, it reads a linked list of symbol files from the global |
| variable to find existing code, and puts a breakpoint in the function |
| so that it can find out about additional code. |
| |
| * Menu: |
| |
| * Declarations:: Relevant C struct declarations |
| * Registering Code:: Steps to register code |
| * Unregistering Code:: Steps to unregister code |
| * Custom Debug Info:: Emit debug information in a custom format |
| |
| |
| File: gdb.info, Node: Declarations, Next: Registering Code, Up: JIT Interface |
| |
| 29.1 JIT Declarations |
| ===================== |
| |
| These are the relevant struct declarations that a C program should |
| include to implement the interface: |
| |
| typedef enum |
| { |
| JIT_NOACTION = 0, |
| JIT_REGISTER_FN, |
| JIT_UNREGISTER_FN |
| } jit_actions_t; |
| |
| struct jit_code_entry |
| { |
| struct jit_code_entry *next_entry; |
| struct jit_code_entry *prev_entry; |
| const char *symfile_addr; |
| uint64_t symfile_size; |
| }; |
| |
| struct jit_descriptor |
| { |
| uint32_t version; |
| /* This type should be jit_actions_t, but we use uint32_t |
| to be explicit about the bitwidth. */ |
| uint32_t action_flag; |
| struct jit_code_entry *relevant_entry; |
| struct jit_code_entry *first_entry; |
| }; |
| |
| /* GDB puts a breakpoint in this function. */ |
| void __attribute__((noinline)) __jit_debug_register_code() { }; |
| |
| /* Make sure to specify the version statically, because the |
| debugger may check the version before we can set it. */ |
| struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 }; |
| |
| If the JIT is multi-threaded, then it is important that the JIT |
| synchronize any modifications to this global data properly, which can |
| easily be done by putting a global mutex around modifications to these |
| structures. |
| |
| |
| File: gdb.info, Node: Registering Code, Next: Unregistering Code, Prev: Declarations, Up: JIT Interface |
| |
| 29.2 Registering Code |
| ===================== |
| |
| To register code with GDB, the JIT should follow this protocol: |
| |
| * Generate an object file in memory with symbols and other desired |
| debug information. The file must include the virtual addresses of |
| the sections. |
| |
| * Create a code entry for the file, which gives the start and size |
| of the symbol file. |
| |
| * Add it to the linked list in the JIT descriptor. |
| |
| * Point the relevant_entry field of the descriptor at the entry. |
| |
| * Set `action_flag' to `JIT_REGISTER' and call |
| `__jit_debug_register_code'. |
| |
| When GDB is attached and the breakpoint fires, GDB uses the |
| `relevant_entry' pointer so it doesn't have to walk the list looking for |
| new code. However, the linked list must still be maintained in order |
| to allow GDB to attach to a running process and still find the symbol |
| files. |
| |
| |
| File: gdb.info, Node: Unregistering Code, Next: Custom Debug Info, Prev: Registering Code, Up: JIT Interface |
| |
| 29.3 Unregistering Code |
| ======================= |
| |
| If code is freed, then the JIT should use the following protocol: |
| |
| * Remove the code entry corresponding to the code from the linked |
| list. |
| |
| * Point the `relevant_entry' field of the descriptor at the code |
| entry. |
| |
| * Set `action_flag' to `JIT_UNREGISTER' and call |
| `__jit_debug_register_code'. |
| |
| If the JIT frees or recompiles code without unregistering it, then |
| GDB and the JIT will leak the memory used for the associated symbol |
| files. |
| |
| |
| File: gdb.info, Node: Custom Debug Info, Prev: Unregistering Code, Up: JIT Interface |
| |
| 29.4 Custom Debug Info |
| ====================== |
| |
| Generating debug information in platform-native file formats (like ELF |
| or COFF) may be an overkill for JIT compilers; especially if all the |
| debug info is used for is displaying a meaningful backtrace. The issue |
| can be resolved by having the JIT writers decide on a debug info format |
| and also provide a reader that parses the debug info generated by the |
| JIT compiler. This section gives a brief overview on writing such a |
| parser. More specific details can be found in the source file |
| `gdb/jit-reader.in', which is also installed as a header at |
| `INCLUDEDIR/gdb/jit-reader.h' for easy inclusion. |
| |
| The reader is implemented as a shared object (so this functionality |
| is not available on platforms which don't allow loading shared objects |
| at runtime). Two GDB commands, `jit-reader-load' and |
| `jit-reader-unload' are provided, to be used to load and unload the |
| readers from a preconfigured directory. Once loaded, the shared object |
| is used the parse the debug information emitted by the JIT compiler. |
| |
| * Menu: |
| |
| * Using JIT Debug Info Readers:: How to use supplied readers correctly |
| * Writing JIT Debug Info Readers:: Creating a debug-info reader |
| |
| |
| File: gdb.info, Node: Using JIT Debug Info Readers, Next: Writing JIT Debug Info Readers, Up: Custom Debug Info |
| |
| 29.4.1 Using JIT Debug Info Readers |
| ----------------------------------- |
| |
| Readers can be loaded and unloaded using the `jit-reader-load' and |
| `jit-reader-unload' commands. |
| |
| `jit-reader-load READER' |
| Load the JIT reader named READER. READER is a shared object |
| specified as either an absolute or a relative file name. In the |
| latter case, GDB will try to load the reader from a pre-configured |
| directory, usually `LIBDIR/gdb/' on a UNIX system (here LIBDIR is |
| the system library directory, often `/usr/local/lib'). |
| |
| Only one reader can be active at a time; trying to load a second |
| reader when one is already loaded will result in GDB reporting an |
| error. A new JIT reader can be loaded by first unloading the |
| current one using `jit-reader-unload' and then invoking |
| `jit-reader-load'. |
| |
| `jit-reader-unload' |
| Unload the currently loaded JIT reader. |
| |
| |
| |
| File: gdb.info, Node: Writing JIT Debug Info Readers, Prev: Using JIT Debug Info Readers, Up: Custom Debug Info |
| |
| 29.4.2 Writing JIT Debug Info Readers |
| ------------------------------------- |
| |
| As mentioned, a reader is essentially a shared object conforming to a |
| certain ABI. This ABI is described in `jit-reader.h'. |
| |
| `jit-reader.h' defines the structures, macros and functions required |
| to write a reader. It is installed (along with GDB), in |
| `INCLUDEDIR/gdb' where INCLUDEDIR is the system include directory. |
| |
| Readers need to be released under a GPL compatible license. A reader |
| can be declared as released under such a license by placing the macro |
| `GDB_DECLARE_GPL_COMPATIBLE_READER' in a source file. |
| |
| The entry point for readers is the symbol `gdb_init_reader', which |
| is expected to be a function with the prototype |
| |
| extern struct gdb_reader_funcs *gdb_init_reader (void); |
| |
| `struct gdb_reader_funcs' contains a set of pointers to callback |
| functions. These functions are executed to read the debug info |
| generated by the JIT compiler (`read'), to unwind stack frames |
| (`unwind') and to create canonical frame IDs (`get_Frame_id'). It also |
| has a callback that is called when the reader is being unloaded |
| (`destroy'). The struct looks like this |
| |
| struct gdb_reader_funcs |
| { |
| /* Must be set to GDB_READER_INTERFACE_VERSION. */ |
| int reader_version; |
| |
| /* For use by the reader. */ |
| void *priv_data; |
| |
| gdb_read_debug_info *read; |
| gdb_unwind_frame *unwind; |
| gdb_get_frame_id *get_frame_id; |
| gdb_destroy_reader *destroy; |
| }; |
| |
| The callbacks are provided with another set of callbacks by GDB to |
| do their job. For `read', these callbacks are passed in a `struct |
| gdb_symbol_callbacks' and for `unwind' and `get_frame_id', in a `struct |
| gdb_unwind_callbacks'. `struct gdb_symbol_callbacks' has callbacks to |
| create new object files and new symbol tables inside those object |
| files. `struct gdb_unwind_callbacks' has callbacks to read registers |
| off the current frame and to write out the values of the registers in |
| the previous frame. Both have a callback (`target_read') to read bytes |
| off the target's address space. |
| |
| |
| File: gdb.info, Node: In-Process Agent, Next: GDB Bugs, Prev: JIT Interface, Up: Top |
| |
| 30 In-Process Agent |
| ******************* |
| |
| The traditional debugging model is conceptually low-speed, but works |
| fine, because most bugs can be reproduced in debugging-mode execution. |
| However, as multi-core or many-core processors are becoming mainstream, |
| and multi-threaded programs become more and more popular, there should |
| be more and more bugs that only manifest themselves at normal-mode |
| execution, for example, thread races, because debugger's interference |
| with the program's timing may conceal the bugs. On the other hand, in |
| some applications, it is not feasible for the debugger to interrupt the |
| program's execution long enough for the developer to learn anything |
| helpful about its behavior. If the program's correctness depends on |
| its real-time behavior, delays introduced by a debugger might cause the |
| program to fail, even when the code itself is correct. It is useful to |
| be able to observe the program's behavior without interrupting it. |
| |
| Therefore, traditional debugging model is too intrusive to reproduce |
| some bugs. In order to reduce the interference with the program, we can |
| reduce the number of operations performed by debugger. The "In-Process |
| Agent", a shared library, is running within the same process with |
| inferior, and is able to perform some debugging operations itself. As |
| a result, debugger is only involved when necessary, and performance of |
| debugging can be improved accordingly. Note that interference with |
| program can be reduced but can't be removed completely, because the |
| in-process agent will still stop or slow down the program. |
| |
| The in-process agent can interpret and execute Agent Expressions |
| (*note Agent Expressions::) during performing debugging operations. The |
| agent expressions can be used for different purposes, such as collecting |
| data in tracepoints, and condition evaluation in breakpoints. |
| |
| You can control whether the in-process agent is used as an aid for |
| debugging with the following commands: |
| |
| `set agent on' |
| Causes the in-process agent to perform some operations on behalf |
| of the debugger. Just which operations requested by the user will |
| be done by the in-process agent depends on the its capabilities. |
| For example, if you request to evaluate breakpoint conditions in |
| the in-process agent, and the in-process agent has such capability |
| as well, then breakpoint conditions will be evaluated in the |
| in-process agent. |
| |
| `set agent off' |
| Disables execution of debugging operations by the in-process |
| agent. All of the operations will be performed by GDB. |
| |
| `show agent' |
| Display the current setting of execution of debugging operations by |
| the in-process agent. |
| |
| * Menu: |
| |
| * In-Process Agent Protocol:: |
| |
| |
| File: gdb.info, Node: In-Process Agent Protocol, Up: In-Process Agent |
| |
| 30.1 In-Process Agent Protocol |
| ============================== |
| |
| The in-process agent is able to communicate with both GDB and GDBserver |
| (*note In-Process Agent::). This section documents the protocol used |
| for communications between GDB or GDBserver and the IPA. In general, |
| GDB or GDBserver sends commands (*note IPA Protocol Commands::) and |
| data to in-process agent, and then in-process agent replies back with |
| the return result of the command, or some other information. The data |
| sent to in-process agent is composed of primitive data types, such as |
| 4-byte or 8-byte type, and composite types, which are called objects |
| (*note IPA Protocol Objects::). |
| |
| * Menu: |
| |
| * IPA Protocol Objects:: |
| * IPA Protocol Commands:: |
| |
| |
| File: gdb.info, Node: IPA Protocol Objects, Next: IPA Protocol Commands, Up: In-Process Agent Protocol |
| |
| 30.1.1 IPA Protocol Objects |
| --------------------------- |
| |
| The commands sent to and results received from agent may contain some |
| complex data types called "objects". |
| |
| The in-process agent is running on the same machine with GDB or |
| GDBserver, so it doesn't have to handle as much differences between two |
| ends as remote protocol (*note Remote Protocol::) tries to handle. |
| However, there are still some differences of two ends in two processes: |
| |
| 1. word size. On some 64-bit machines, GDB or GDBserver can be |
| compiled as a 64-bit executable, while in-process agent is a |
| 32-bit one. |
| |
| 2. ABI. Some machines may have multiple types of ABI, GDB or |
| GDBserver is compiled with one, and in-process agent is compiled |
| with the other one. |
| |
| Here are the IPA Protocol Objects: |
| |
| 1. agent expression object. It represents an agent expression (*note |
| Agent Expressions::). |
| |
| 2. tracepoint action object. It represents a tracepoint action |
| (*note Tracepoint Action Lists: Tracepoint Actions.) to collect |
| registers, memory, static trace data and to evaluate expression. |
| |
| 3. tracepoint object. It represents a tracepoint (*note |
| Tracepoints::). |
| |
| The following table describes important attributes of each IPA |
| protocol object: |
| |
| Name Size Description |
| --------------------------------------------------------------------------- |
| _agent expression |
| object_ |
| length 4 length of bytes code |
| byte code LENGTH contents of byte code |
| _tracepoint action |
| for collecting |
| memory_ |
| 'M' 1 type of tracepoint action |
| addr 8 if BASEREG is `-1', ADDR is the |
| address of the lowest byte to |
| collect, otherwise ADDR is the |
| offset of BASEREG for memory |
| collecting. |
| len 8 length of memory for collecting |
| basereg 4 the register number containing the |
| starting memory address for |
| collecting. |
| _tracepoint action |
| for collecting |
| registers_ |
| 'R' 1 type of tracepoint action |
| _tracepoint action |
| for collecting static |
| trace data_ |
| 'L' 1 type of tracepoint action |
| _tracepoint action |
| for expression |
| evaluation_ |
| 'X' 1 type of tracepoint action |
| agent expression length of *note agent expression object:: |
| _tracepoint object_ |
| number 4 number of tracepoint |
| address 8 address of tracepoint inserted on |
| type 4 type of tracepoint |
| enabled 1 enable or disable of tracepoint |
| step_count 8 step |
| pass_count 8 pass |
| numactions 4 number of tracepoint actions |
| hit count 8 hit count |
| trace frame usage 8 trace frame usage |
| compiled_cond 8 compiled condition |
| orig_size 8 orig size |
| condition 4 if zero if condition is NULL, |
| condition is otherwise is *note agent expression |
| NULL object:: |
| otherwise |
| length of |
| *note agent |
| expression |
| object:: |
| actions variable numactions number of *note |
| tracepoint action object:: |
| |
| |
| File: gdb.info, Node: IPA Protocol Commands, Prev: IPA Protocol Objects, Up: In-Process Agent Protocol |
| |
| 30.1.2 IPA Protocol Commands |
| ---------------------------- |
| |
| The spaces in each command are delimiters to ease reading this commands |
| specification. They don't exist in real commands. |
| |
| `FastTrace:TRACEPOINT_OBJECT GDB_JUMP_PAD_HEAD' |
| Installs a new fast tracepoint described by TRACEPOINT_OBJECT |
| (*note tracepoint object::). GDB_JUMP_PAD_HEAD, 8-byte long, is |
| the head of "jumppad", which is used to jump to data collection |
| routine in IPA finally. |
| |
| Replies: |
| `OK TARGET_ADDRESS GDB_JUMP_PAD_HEAD FJUMP_SIZE FJUMP' |
| TARGET_ADDRESS is address of tracepoint in the inferior. |
| GDB_JUMP_PAD_HEAD is updated head of jumppad. Both of |
| TARGET_ADDRESS and GDB_JUMP_PAD_HEAD are 8-byte long. FJUMP |
| contains a sequence of instructions jump to jumppad entry. |
| FJUMP_SIZE, 4-byte long, is the size of FJUMP. |
| |
| `E NN' |
| for an error |
| |
| |
| `close' |
| Closes the in-process agent. This command is sent when GDB or |
| GDBserver is about to kill inferiors. |
| |
| `qTfSTM' |
| *Note qTfSTM::. |
| |
| `qTsSTM' |
| *Note qTsSTM::. |
| |
| `qTSTMat' |
| *Note qTSTMat::. |
| |
| `probe_marker_at:ADDRESS' |
| Asks in-process agent to probe the marker at ADDRESS. |
| |
| Replies: |
| `E NN' |
| for an error |
| |
| `unprobe_marker_at:ADDRESS' |
| Asks in-process agent to unprobe the marker at ADDRESS. |
| |
| |
| File: gdb.info, Node: GDB Bugs, Next: Command Line Editing, Prev: In-Process Agent, Up: Top |
| |
| 31 Reporting Bugs in GDB |
| ************************ |
| |
| Your bug reports play an essential role in making GDB reliable. |
| |
| Reporting a bug may help you by bringing a solution to your problem, |
| or it may not. But in any case the principal function of a bug report |
| is to help the entire community by making the next version of GDB work |
| better. Bug reports are your contribution to the maintenance of GDB. |
| |
| In order for a bug report to serve its purpose, you must include the |
| information that enables us to fix the bug. |
| |
| * Menu: |
| |
| * Bug Criteria:: Have you found a bug? |
| * Bug Reporting:: How to report bugs |
| |
| |
| File: gdb.info, Node: Bug Criteria, Next: Bug Reporting, Up: GDB Bugs |
| |
| 31.1 Have You Found a Bug? |
| ========================== |
| |
| If you are not sure whether you have found a bug, here are some |
| guidelines: |
| |
| * If the debugger gets a fatal signal, for any input whatever, that |
| is a GDB bug. Reliable debuggers never crash. |
| |
| * If GDB produces an error message for valid input, that is a bug. |
| (Note that if you're cross debugging, the problem may also be |
| somewhere in the connection to the target.) |
| |
| * If GDB does not produce an error message for invalid input, that |
| is a bug. However, you should note that your idea of "invalid |
| input" might be our idea of "an extension" or "support for |
| traditional practice". |
| |
| * If you are an experienced user of debugging tools, your suggestions |
| for improvement of GDB are welcome in any case. |
| |
| |
| File: gdb.info, Node: Bug Reporting, Prev: Bug Criteria, Up: GDB Bugs |
| |
| 31.2 How to Report Bugs |
| ======================= |
| |
| A number of companies and individuals offer support for GNU products. |
| If you obtained GDB from a support organization, we recommend you |
| contact that organization first. |
| |
| You can find contact information for many support companies and |
| individuals in the file `etc/SERVICE' in the GNU Emacs distribution. |
| |
| In any event, we also recommend that you submit bug reports for GDB. |
| The preferred method is to submit them directly using GDB's Bugs web |
| page (http://www.gnu.org/software/gdb/bugs/). Alternatively, the |
| e-mail gateway <bug-gdb@gnu.org> can be used. |
| |
| *Do not send bug reports to `info-gdb', or to `help-gdb', or to any |
| newsgroups.* Most users of GDB do not want to receive bug reports. |
| Those that do have arranged to receive `bug-gdb'. |
| |
| The mailing list `bug-gdb' has a newsgroup `gnu.gdb.bug' which |
| serves as a repeater. The mailing list and the newsgroup carry exactly |
| the same messages. Often people think of posting bug reports to the |
| newsgroup instead of mailing them. This appears to work, but it has one |
| problem which can be crucial: a newsgroup posting often lacks a mail |
| path back to the sender. Thus, if we need to ask for more information, |
| we may be unable to reach you. For this reason, it is better to send |
| bug reports to the mailing list. |
| |
| The fundamental principle of reporting bugs usefully is this: |
| *report all the facts*. If you are not sure whether to state a fact or |
| leave it out, state it! |
| |
| Often people omit facts because they think they know what causes the |
| problem and assume that some details do not matter. Thus, you might |
| assume that the name of the variable you use in an example does not |
| matter. Well, probably it does not, but one cannot be sure. Perhaps |
| the bug is a stray memory reference which happens to fetch from the |
| location where that name is stored in memory; perhaps, if the name were |
| different, the contents of that location would fool the debugger into |
| doing the right thing despite the bug. Play it safe and give a |
| specific, complete example. That is the easiest thing for you to do, |
| and the most helpful. |
| |
| Keep in mind that the purpose of a bug report is to enable us to fix |
| the bug. It may be that the bug has been reported previously, but |
| neither you nor we can know that unless your bug report is complete and |
| self-contained. |
| |
| Sometimes people give a few sketchy facts and ask, "Does this ring a |
| bell?" Those bug reports are useless, and we urge everyone to _refuse |
| to respond to them_ except to chide the sender to report bugs properly. |
| |
| To enable us to fix the bug, you should include all these things: |
| |
| * The version of GDB. GDB announces it if you start with no |
| arguments; you can also print it at any time using `show version'. |
| |
| Without this, we will not know whether there is any point in |
| looking for the bug in the current version of GDB. |
| |
| * The type of machine you are using, and the operating system name |
| and version number. |
| |
| * The details of the GDB build-time configuration. GDB shows these |
| details if you invoke it with the `--configuration' command-line |
| option, or if you type `show configuration' at GDB's prompt. |
| |
| * What compiler (and its version) was used to compile GDB--e.g. |
| "gcc-2.8.1". |
| |
| * What compiler (and its version) was used to compile the program |
| you are debugging--e.g. "gcc-2.8.1", or "HP92453-01 A.10.32.03 HP |
| C Compiler". For GCC, you can say `gcc --version' to get this |
| information; for other compilers, see the documentation for those |
| compilers. |
| |
| * The command arguments you gave the compiler to compile your |
| example and observe the bug. For example, did you use `-O'? To |
| guarantee you will not omit something important, list them all. A |
| copy of the Makefile (or the output from make) is sufficient. |
| |
| If we were to try to guess the arguments, we would probably guess |
| wrong and then we might not encounter the bug. |
| |
| * A complete input script, and all necessary source files, that will |
| reproduce the bug. |
| |
| * A description of what behavior you observe that you believe is |
| incorrect. For example, "It gets a fatal signal." |
| |
| Of course, if the bug is that GDB gets a fatal signal, then we |
| will certainly notice it. But if the bug is incorrect output, we |
| might not notice unless it is glaringly wrong. You might as well |
| not give us a chance to make a mistake. |
| |
| Even if the problem you experience is a fatal signal, you should |
| still say so explicitly. Suppose something strange is going on, |
| such as, your copy of GDB is out of synch, or you have encountered |
| a bug in the C library on your system. (This has happened!) Your |
| copy might crash and ours would not. If you told us to expect a |
| crash, then when ours fails to crash, we would know that the bug |
| was not happening for us. If you had not told us to expect a |
| crash, then we would not be able to draw any conclusion from our |
| observations. |
| |
| To collect all this information, you can use a session recording |
| program such as `script', which is available on many Unix systems. |
| Just run your GDB session inside `script' and then include the |
| `typescript' file with your bug report. |
| |
| Another way to record a GDB session is to run GDB inside Emacs and |
| then save the entire buffer to a file. |
| |
| * If you wish to suggest changes to the GDB source, send us context |
| diffs. If you even discuss something in the GDB source, refer to |
| it by context, not by line number. |
| |
| The line numbers in our development sources will not match those |
| in your sources. Your line numbers would convey no useful |
| information to us. |
| |
| |
| Here are some things that are not necessary: |
| |
| * A description of the envelope of the bug. |
| |
| Often people who encounter a bug spend a lot of time investigating |
| which changes to the input file will make the bug go away and which |
| changes will not affect it. |
| |
| This is often time consuming and not very useful, because the way |
| we will find the bug is by running a single example under the |
| debugger with breakpoints, not by pure deduction from a series of |
| examples. We recommend that you save your time for something else. |
| |
| Of course, if you can find a simpler example to report _instead_ |
| of the original one, that is a convenience for us. Errors in the |
| output will be easier to spot, running under the debugger will take |
| less time, and so on. |
| |
| However, simplification is not vital; if you do not want to do |
| this, report the bug anyway and send us the entire test case you |
| used. |
| |
| * A patch for the bug. |
| |
| A patch for the bug does help us if it is a good one. But do not |
| omit the necessary information, such as the test case, on the |
| assumption that a patch is all we need. We might see problems |
| with your patch and decide to fix the problem another way, or we |
| might not understand it at all. |
| |
| Sometimes with a program as complicated as GDB it is very hard to |
| construct an example that will make the program follow a certain |
| path through the code. If you do not send us the example, we will |
| not be able to construct one, so we will not be able to verify |
| that the bug is fixed. |
| |
| And if we cannot understand what bug you are trying to fix, or why |
| your patch should be an improvement, we will not install it. A |
| test case will help us to understand. |
| |
| * A guess about what the bug is or what it depends on. |
| |
| Such guesses are usually wrong. Even we cannot guess right about |
| such things without first using the debugger to find the facts. |
| |
| |
| File: gdb.info, Node: Command Line Editing, Next: Using History Interactively, Prev: GDB Bugs, Up: Top |
| |
| 32 Command Line Editing |
| *********************** |
| |
| This chapter describes the basic features of the GNU command line |
| editing interface. |
| |
| * Menu: |
| |
| * Introduction and Notation:: Notation used in this text. |
| * Readline Interaction:: The minimum set of commands for editing a line. |
| * Readline Init File:: Customizing Readline from a user's view. |
| * Bindable Readline Commands:: A description of most of the Readline commands |
| available for binding |
| * Readline vi Mode:: A short description of how to make Readline |
| behave like the vi editor. |
| |
| |
| File: gdb.info, Node: Introduction and Notation, Next: Readline Interaction, Up: Command Line Editing |
| |
| 32.1 Introduction to Line Editing |
| ================================= |
| |
| The following paragraphs describe the notation used to represent |
| keystrokes. |
| |
| The text `C-k' is read as `Control-K' and describes the character |
| produced when the <k> key is pressed while the Control key is depressed. |
| |
| The text `M-k' is read as `Meta-K' and describes the character |
| produced when the Meta key (if you have one) is depressed, and the <k> |
| key is pressed. The Meta key is labeled <ALT> on many keyboards. On |
| keyboards with two keys labeled <ALT> (usually to either side of the |
| space bar), the <ALT> on the left side is generally set to work as a |
| Meta key. The <ALT> key on the right may also be configured to work as |
| a Meta key or may be configured as some other modifier, such as a |
| Compose key for typing accented characters. |
| |
| If you do not have a Meta or <ALT> key, or another key working as a |
| Meta key, the identical keystroke can be generated by typing <ESC> |
| _first_, and then typing <k>. Either process is known as "metafying" |
| the <k> key. |
| |
| The text `M-C-k' is read as `Meta-Control-k' and describes the |
| character produced by "metafying" `C-k'. |
| |
| In addition, several keys have their own names. Specifically, |
| <DEL>, <ESC>, <LFD>, <SPC>, <RET>, and <TAB> all stand for themselves |
| when seen in this text, or in an init file (*note Readline Init File::). |
| If your keyboard lacks a <LFD> key, typing <C-j> will produce the |
| desired character. The <RET> key may be labeled <Return> or <Enter> on |
| some keyboards. |
| |
| |
| File: gdb.info, Node: Readline Interaction, Next: Readline Init File, Prev: Introduction and Notation, Up: Command Line Editing |
| |
| 32.2 Readline Interaction |
| ========================= |
| |
| Often during an interactive session you type in a long line of text, |
| only to notice that the first word on the line is misspelled. The |
| Readline library gives you a set of commands for manipulating the text |
| as you type it in, allowing you to just fix your typo, and not forcing |
| you to retype the majority of the line. Using these editing commands, |
| you move the cursor to the place that needs correction, and delete or |
| insert the text of the corrections. Then, when you are satisfied with |
| the line, you simply press <RET>. You do not have to be at the end of |
| the line to press <RET>; the entire line is accepted regardless of the |
| location of the cursor within the line. |
| |
| * Menu: |
| |
| * Readline Bare Essentials:: The least you need to know about Readline. |
| * Readline Movement Commands:: Moving about the input line. |
| * Readline Killing Commands:: How to delete text, and how to get it back! |
| * Readline Arguments:: Giving numeric arguments to commands. |
| * Searching:: Searching through previous lines. |
| |
| |
| File: gdb.info, Node: Readline Bare Essentials, Next: Readline Movement Commands, Up: Readline Interaction |
| |
| 32.2.1 Readline Bare Essentials |
| ------------------------------- |
| |
| In order to enter characters into the line, simply type them. The typed |
| character appears where the cursor was, and then the cursor moves one |
| space to the right. If you mistype a character, you can use your erase |
| character to back up and delete the mistyped character. |
| |
| Sometimes you may mistype a character, and not notice the error |
| until you have typed several other characters. In that case, you can |
| type `C-b' to move the cursor to the left, and then correct your |
| mistake. Afterwards, you can move the cursor to the right with `C-f'. |
| |
| When you add text in the middle of a line, you will notice that |
| characters to the right of the cursor are `pushed over' to make room |
| for the text that you have inserted. Likewise, when you delete text |
| behind the cursor, characters to the right of the cursor are `pulled |
| back' to fill in the blank space created by the removal of the text. A |
| list of the bare essentials for editing the text of an input line |
| follows. |
| |
| `C-b' |
| Move back one character. |
| |
| `C-f' |
| Move forward one character. |
| |
| <DEL> or <Backspace> |
| Delete the character to the left of the cursor. |
| |
| `C-d' |
| Delete the character underneath the cursor. |
| |
| Printing characters |
| Insert the character into the line at the cursor. |
| |
| `C-_' or `C-x C-u' |
| Undo the last editing command. You can undo all the way back to an |
| empty line. |
| |
| (Depending on your configuration, the <Backspace> key be set to delete |
| the character to the left of the cursor and the <DEL> key set to delete |
| the character underneath the cursor, like `C-d', rather than the |
| character to the left of the cursor.) |
| |
| |
| File: gdb.info, Node: Readline Movement Commands, Next: Readline Killing Commands, Prev: Readline Bare Essentials, Up: Readline Interaction |
| |
| 32.2.2 Readline Movement Commands |
| --------------------------------- |
| |
| The above table describes the most basic keystrokes that you need in |
| order to do editing of the input line. For your convenience, many |
| other commands have been added in addition to `C-b', `C-f', `C-d', and |
| <DEL>. Here are some commands for moving more rapidly about the line. |
| |
| `C-a' |
| Move to the start of the line. |
| |
| `C-e' |
| Move to the end of the line. |
| |
| `M-f' |
| Move forward a word, where a word is composed of letters and |
| digits. |
| |
| `M-b' |
| Move backward a word. |
| |
| `C-l' |
| Clear the screen, reprinting the current line at the top. |
| |
| Notice how `C-f' moves forward a character, while `M-f' moves |
| forward a word. It is a loose convention that control keystrokes |
| operate on characters while meta keystrokes operate on words. |
| |
| |
| File: gdb.info, Node: Readline Killing Commands, Next: Readline Arguments, Prev: Readline Movement Commands, Up: Readline Interaction |
| |
| 32.2.3 Readline Killing Commands |
| -------------------------------- |
| |
| "Killing" text means to delete the text from the line, but to save it |
| away for later use, usually by "yanking" (re-inserting) it back into |
| the line. (`Cut' and `paste' are more recent jargon for `kill' and |
| `yank'.) |
| |
| If the description for a command says that it `kills' text, then you |
| can be sure that you can get the text back in a different (or the same) |
| place later. |
| |
| When you use a kill command, the text is saved in a "kill-ring". |
| Any number of consecutive kills save all of the killed text together, so |
| that when you yank it back, you get it all. The kill ring is not line |
| specific; the text that you killed on a previously typed line is |
| available to be yanked back later, when you are typing another line. |
| |
| Here is the list of commands for killing text. |
| |
| `C-k' |
| Kill the text from the current cursor position to the end of the |
| line. |
| |
| `M-d' |
| Kill from the cursor to the end of the current word, or, if between |
| words, to the end of the next word. Word boundaries are the same |
| as those used by `M-f'. |
| |
| `M-<DEL>' |
| Kill from the cursor the start of the current word, or, if between |
| words, to the start of the previous word. Word boundaries are the |
| same as those used by `M-b'. |
| |
| `C-w' |
| Kill from the cursor to the previous whitespace. This is |
| different than `M-<DEL>' because the word boundaries differ. |
| |
| |
| Here is how to "yank" the text back into the line. Yanking means to |
| copy the most-recently-killed text from the kill buffer. |
| |
| `C-y' |
| Yank the most recently killed text back into the buffer at the |
| cursor. |
| |
| `M-y' |
| Rotate the kill-ring, and yank the new top. You can only do this |
| if the prior command is `C-y' or `M-y'. |
| |
| |
| File: gdb.info, Node: Readline Arguments, Next: Searching, Prev: Readline Killing Commands, Up: Readline Interaction |
| |
| 32.2.4 Readline Arguments |
| ------------------------- |
| |
| You can pass numeric arguments to Readline commands. Sometimes the |
| argument acts as a repeat count, other times it is the sign of the |
| argument that is significant. If you pass a negative argument to a |
| command which normally acts in a forward direction, that command will |
| act in a backward direction. For example, to kill text back to the |
| start of the line, you might type `M-- C-k'. |
| |
| The general way to pass numeric arguments to a command is to type |
| meta digits before the command. If the first `digit' typed is a minus |
| sign (`-'), then the sign of the argument will be negative. Once you |
| have typed one meta digit to get the argument started, you can type the |
| remainder of the digits, and then the command. For example, to give |
| the `C-d' command an argument of 10, you could type `M-1 0 C-d', which |
| will delete the next ten characters on the input line. |
| |
| |
| File: gdb.info, Node: Searching, Prev: Readline Arguments, Up: Readline Interaction |
| |
| 32.2.5 Searching for Commands in the History |
| -------------------------------------------- |
| |
| Readline provides commands for searching through the command history |
| for lines containing a specified string. There are two search modes: |
| "incremental" and "non-incremental". |
| |
| Incremental searches begin before the user has finished typing the |
| search string. As each character of the search string is typed, |
| Readline displays the next entry from the history matching the string |
| typed so far. An incremental search requires only as many characters |
| as needed to find the desired history entry. To search backward in the |
| history for a particular string, type `C-r'. Typing `C-s' searches |
| forward through the history. The characters present in the value of |
| the `isearch-terminators' variable are used to terminate an incremental |
| search. If that variable has not been assigned a value, the <ESC> and |
| `C-J' characters will terminate an incremental search. `C-g' will |
| abort an incremental search and restore the original line. When the |
| search is terminated, the history entry containing the search string |
| becomes the current line. |
| |
| To find other matching entries in the history list, type `C-r' or |
| `C-s' as appropriate. This will search backward or forward in the |
| history for the next entry matching the search string typed so far. |
| Any other key sequence bound to a Readline command will terminate the |
| search and execute that command. For instance, a <RET> will terminate |
| the search and accept the line, thereby executing the command from the |
| history list. A movement command will terminate the search, make the |
| last line found the current line, and begin editing. |
| |
| Readline remembers the last incremental search string. If two |
| `C-r's are typed without any intervening characters defining a new |
| search string, any remembered search string is used. |
| |
| Non-incremental searches read the entire search string before |
| starting to search for matching history lines. The search string may be |
| typed by the user or be part of the contents of the current line. |
| |
| |
| File: gdb.info, Node: Readline Init File, Next: Bindable Readline Commands, Prev: Readline Interaction, Up: Command Line Editing |
| |
| 32.3 Readline Init File |
| ======================= |
| |
| Although the Readline library comes with a set of Emacs-like |
| keybindings installed by default, it is possible to use a different set |
| of keybindings. Any user can customize programs that use Readline by |
| putting commands in an "inputrc" file, conventionally in his home |
| directory. The name of this file is taken from the value of the |
| environment variable `INPUTRC'. If that variable is unset, the default |
| is `~/.inputrc'. If that file does not exist or cannot be read, the |
| ultimate default is `/etc/inputrc'. |
| |
| When a program which uses the Readline library starts up, the init |
| file is read, and the key bindings are set. |
| |
| In addition, the `C-x C-r' command re-reads this init file, thus |
| incorporating any changes that you might have made to it. |
| |
| * Menu: |
| |
| * Readline Init File Syntax:: Syntax for the commands in the inputrc file. |
| |
| * Conditional Init Constructs:: Conditional key bindings in the inputrc file. |
| |
| * Sample Init File:: An example inputrc file. |
| |
| |
| File: gdb.info, Node: Readline Init File Syntax, Next: Conditional Init Constructs, Up: Readline Init File |
| |
| 32.3.1 Readline Init File Syntax |
| -------------------------------- |
| |
| There are only a few basic constructs allowed in the Readline init |
| file. Blank lines are ignored. Lines beginning with a `#' are |
| comments. Lines beginning with a `$' indicate conditional constructs |
| (*note Conditional Init Constructs::). Other lines denote variable |
| settings and key bindings. |
| |
| Variable Settings |
| You can modify the run-time behavior of Readline by altering the |
| values of variables in Readline using the `set' command within the |
| init file. The syntax is simple: |
| |
| set VARIABLE VALUE |
| |
| Here, for example, is how to change from the default Emacs-like |
| key binding to use `vi' line editing commands: |
| |
| set editing-mode vi |
| |
| Variable names and values, where appropriate, are recognized |
| without regard to case. Unrecognized variable names are ignored. |
| |
| Boolean variables (those that can be set to on or off) are set to |
| on if the value is null or empty, ON (case-insensitive), or 1. |
| Any other value results in the variable being set to off. |
| |
| A great deal of run-time behavior is changeable with the following |
| variables. |
| |
| `bell-style' |
| Controls what happens when Readline wants to ring the |
| terminal bell. If set to `none', Readline never rings the |
| bell. If set to `visible', Readline uses a visible bell if |
| one is available. If set to `audible' (the default), |
| Readline attempts to ring the terminal's bell. |
| |
| `bind-tty-special-chars' |
| If set to `on', Readline attempts to bind the control |
| characters treated specially by the kernel's terminal driver |
| to their Readline equivalents. |
| |
| `comment-begin' |
| The string to insert at the beginning of the line when the |
| `insert-comment' command is executed. The default value is |
| `"#"'. |
| |
| `completion-display-width' |
| The number of screen columns used to display possible matches |
| when performing completion. The value is ignored if it is |
| less than 0 or greater than the terminal screen width. A |
| value of 0 will cause matches to be displayed one per line. |
| The default value is -1. |
| |
| `completion-ignore-case' |
| If set to `on', Readline performs filename matching and |
| completion in a case-insensitive fashion. The default value |
| is `off'. |
| |
| `completion-map-case' |
| If set to `on', and COMPLETION-IGNORE-CASE is enabled, |
| Readline treats hyphens (`-') and underscores (`_') as |
| equivalent when performing case-insensitive filename matching |
| and completion. |
| |
| `completion-prefix-display-length' |
| The length in characters of the common prefix of a list of |
| possible completions that is displayed without modification. |
| When set to a value greater than zero, common prefixes longer |
| than this value are replaced with an ellipsis when displaying |
| possible completions. |
| |
| `completion-query-items' |
| The number of possible completions that determines when the |
| user is asked whether the list of possibilities should be |
| displayed. If the number of possible completions is greater |
| than this value, Readline will ask the user whether or not he |
| wishes to view them; otherwise, they are simply listed. This |
| variable must be set to an integer value greater than or |
| equal to 0. A negative value means Readline should never ask. |
| The default limit is `100'. |
| |
| `convert-meta' |
| If set to `on', Readline will convert characters with the |
| eighth bit set to an ASCII key sequence by stripping the |
| eighth bit and prefixing an <ESC> character, converting them |
| to a meta-prefixed key sequence. The default value is `on'. |
| |
| `disable-completion' |
| If set to `On', Readline will inhibit word completion. |
| Completion characters will be inserted into the line as if |
| they had been mapped to `self-insert'. The default is `off'. |
| |
| `editing-mode' |
| The `editing-mode' variable controls which default set of key |
| bindings is used. By default, Readline starts up in Emacs |
| editing mode, where the keystrokes are most similar to Emacs. |
| This variable can be set to either `emacs' or `vi'. |
| |
| `echo-control-characters' |
| When set to `on', on operating systems that indicate they |
| support it, readline echoes a character corresponding to a |
| signal generated from the keyboard. The default is `on'. |
| |
| `enable-keypad' |
| When set to `on', Readline will try to enable the application |
| keypad when it is called. Some systems need this to enable |
| the arrow keys. The default is `off'. |
| |
| `enable-meta-key' |
| When set to `on', Readline will try to enable any meta |
| modifier key the terminal claims to support when it is |
| called. On many terminals, the meta key is used to send |
| eight-bit characters. The default is `on'. |
| |
| `expand-tilde' |
| If set to `on', tilde expansion is performed when Readline |
| attempts word completion. The default is `off'. |
| |
| `history-preserve-point' |
| If set to `on', the history code attempts to place the point |
| (the current cursor position) at the same location on each |
| history line retrieved with `previous-history' or |
| `next-history'. The default is `off'. |
| |
| `history-size' |
| Set the maximum number of history entries saved in the |
| history list. If set to zero, the number of entries in the |
| history list is not limited. |
| |
| `horizontal-scroll-mode' |
| This variable can be set to either `on' or `off'. Setting it |
| to `on' means that the text of the lines being edited will |
| scroll horizontally on a single screen line when they are |
| longer than the width of the screen, instead of wrapping onto |
| a new screen line. By default, this variable is set to `off'. |
| |
| `input-meta' |
| If set to `on', Readline will enable eight-bit input (it will |
| not clear the eighth bit in the characters it reads), |
| regardless of what the terminal claims it can support. The |
| default value is `off'. The name `meta-flag' is a synonym |
| for this variable. |
| |
| `isearch-terminators' |
| The string of characters that should terminate an incremental |
| search without subsequently executing the character as a |
| command (*note Searching::). If this variable has not been |
| given a value, the characters <ESC> and `C-J' will terminate |
| an incremental search. |
| |
| `keymap' |
| Sets Readline's idea of the current keymap for key binding |
| commands. Acceptable `keymap' names are `emacs', |
| `emacs-standard', `emacs-meta', `emacs-ctlx', `vi', `vi-move', |
| `vi-command', and `vi-insert'. `vi' is equivalent to |
| `vi-command'; `emacs' is equivalent to `emacs-standard'. The |
| default value is `emacs'. The value of the `editing-mode' |
| variable also affects the default keymap. |
| |
| `mark-directories' |
| If set to `on', completed directory names have a slash |
| appended. The default is `on'. |
| |
| `mark-modified-lines' |
| This variable, when set to `on', causes Readline to display an |
| asterisk (`*') at the start of history lines which have been |
| modified. This variable is `off' by default. |
| |
| `mark-symlinked-directories' |
| If set to `on', completed names which are symbolic links to |
| directories have a slash appended (subject to the value of |
| `mark-directories'). The default is `off'. |
| |
| `match-hidden-files' |
| This variable, when set to `on', causes Readline to match |
| files whose names begin with a `.' (hidden files) when |
| performing filename completion. If set to `off', the leading |
| `.' must be supplied by the user in the filename to be |
| completed. This variable is `on' by default. |
| |
| `menu-complete-display-prefix' |
| If set to `on', menu completion displays the common prefix of |
| the list of possible completions (which may be empty) before |
| cycling through the list. The default is `off'. |
| |
| `output-meta' |
| If set to `on', Readline will display characters with the |
| eighth bit set directly rather than as a meta-prefixed escape |
| sequence. The default is `off'. |
| |
| `page-completions' |
| If set to `on', Readline uses an internal `more'-like pager |
| to display a screenful of possible completions at a time. |
| This variable is `on' by default. |
| |
| `print-completions-horizontally' |
| If set to `on', Readline will display completions with matches |
| sorted horizontally in alphabetical order, rather than down |
| the screen. The default is `off'. |
| |
| `revert-all-at-newline' |
| If set to `on', Readline will undo all changes to history |
| lines before returning when `accept-line' is executed. By |
| default, history lines may be modified and retain individual |
| undo lists across calls to `readline'. The default is `off'. |
| |
| `show-all-if-ambiguous' |
| This alters the default behavior of the completion functions. |
| If set to `on', words which have more than one possible |
| completion cause the matches to be listed immediately instead |
| of ringing the bell. The default value is `off'. |
| |
| `show-all-if-unmodified' |
| This alters the default behavior of the completion functions |
| in a fashion similar to SHOW-ALL-IF-AMBIGUOUS. If set to |
| `on', words which have more than one possible completion |
| without any possible partial completion (the possible |
| completions don't share a common prefix) cause the matches to |
| be listed immediately instead of ringing the bell. The |
| default value is `off'. |
| |
| `skip-completed-text' |
| If set to `on', this alters the default completion behavior |
| when inserting a single match into the line. It's only |
| active when performing completion in the middle of a word. |
| If enabled, readline does not insert characters from the |
| completion that match characters after point in the word |
| being completed, so portions of the word following the cursor |
| are not duplicated. For instance, if this is enabled, |
| attempting completion when the cursor is after the `e' in |
| `Makefile' will result in `Makefile' rather than |
| `Makefilefile', assuming there is a single possible |
| completion. The default value is `off'. |
| |
| `visible-stats' |
| If set to `on', a character denoting a file's type is |
| appended to the filename when listing possible completions. |
| The default is `off'. |
| |
| |
| Key Bindings |
| The syntax for controlling key bindings in the init file is |
| simple. First you need to find the name of the command that you |
| want to change. The following sections contain tables of the |
| command name, the default keybinding, if any, and a short |
| description of what the command does. |
| |
| Once you know the name of the command, simply place on a line in |
| the init file the name of the key you wish to bind the command to, |
| a colon, and then the name of the command. There can be no space |
| between the key name and the colon - that will be interpreted as |
| part of the key name. The name of the key can be expressed in |
| different ways, depending on what you find most comfortable. |
| |
| In addition to command names, readline allows keys to be bound to |
| a string that is inserted when the key is pressed (a MACRO). |
| |
| KEYNAME: FUNCTION-NAME or MACRO |
| KEYNAME is the name of a key spelled out in English. For |
| example: |
| Control-u: universal-argument |
| Meta-Rubout: backward-kill-word |
| Control-o: "> output" |
| |
| In the above example, `C-u' is bound to the function |
| `universal-argument', `M-DEL' is bound to the function |
| `backward-kill-word', and `C-o' is bound to run the macro |
| expressed on the right hand side (that is, to insert the text |
| `> output' into the line). |
| |
| A number of symbolic character names are recognized while |
| processing this key binding syntax: DEL, ESC, ESCAPE, LFD, |
| NEWLINE, RET, RETURN, RUBOUT, SPACE, SPC, and TAB. |
| |
| "KEYSEQ": FUNCTION-NAME or MACRO |
| KEYSEQ differs from KEYNAME above in that strings denoting an |
| entire key sequence can be specified, by placing the key |
| sequence in double quotes. Some GNU Emacs style key escapes |
| can be used, as in the following example, but the special |
| character names are not recognized. |
| |
| "\C-u": universal-argument |
| "\C-x\C-r": re-read-init-file |
| "\e[11~": "Function Key 1" |
| |
| In the above example, `C-u' is again bound to the function |
| `universal-argument' (just as it was in the first example), |
| `C-x C-r' is bound to the function `re-read-init-file', and |
| `<ESC> <[> <1> <1> <~>' is bound to insert the text `Function |
| Key 1'. |
| |
| |
| The following GNU Emacs style escape sequences are available when |
| specifying key sequences: |
| |
| `\C-' |
| control prefix |
| |
| `\M-' |
| meta prefix |
| |
| `\e' |
| an escape character |
| |
| `\\' |
| backslash |
| |
| `\"' |
| <">, a double quotation mark |
| |
| `\'' |
| <'>, a single quote or apostrophe |
| |
| In addition to the GNU Emacs style escape sequences, a second set |
| of backslash escapes is available: |
| |
| `\a' |
| alert (bell) |
| |
| `\b' |
| backspace |
| |
| `\d' |
| delete |
| |
| `\f' |
| form feed |
| |
| `\n' |
| newline |
| |
| `\r' |
| carriage return |
| |
| `\t' |
| horizontal tab |
| |
| `\v' |
| vertical tab |
| |
| `\NNN' |
| the eight-bit character whose value is the octal value NNN |
| (one to three digits) |
| |
| `\xHH' |
| the eight-bit character whose value is the hexadecimal value |
| HH (one or two hex digits) |
| |
| When entering the text of a macro, single or double quotes must be |
| used to indicate a macro definition. Unquoted text is assumed to |
| be a function name. In the macro body, the backslash escapes |
| described above are expanded. Backslash will quote any other |
| character in the macro text, including `"' and `''. For example, |
| the following binding will make `C-x \' insert a single `\' into |
| the line: |
| "\C-x\\": "\\" |
| |
| |
| |
| File: gdb.info, Node: Conditional Init Constructs, Next: Sample Init File, Prev: Readline Init File Syntax, Up: Readline Init File |
| |
| 32.3.2 Conditional Init Constructs |
| ---------------------------------- |
| |
| Readline implements a facility similar in spirit to the conditional |
| compilation features of the C preprocessor which allows key bindings |
| and variable settings to be performed as the result of tests. There |
| are four parser directives used. |
| |
| `$if' |
| The `$if' construct allows bindings to be made based on the |
| editing mode, the terminal being used, or the application using |
| Readline. The text of the test extends to the end of the line; no |
| characters are required to isolate it. |
| |
| `mode' |
| The `mode=' form of the `$if' directive is used to test |
| whether Readline is in `emacs' or `vi' mode. This may be |
| used in conjunction with the `set keymap' command, for |
| instance, to set bindings in the `emacs-standard' and |
| `emacs-ctlx' keymaps only if Readline is starting out in |
| `emacs' mode. |
| |
| `term' |
| The `term=' form may be used to include terminal-specific key |
| bindings, perhaps to bind the key sequences output by the |
| terminal's function keys. The word on the right side of the |
| `=' is tested against both the full name of the terminal and |
| the portion of the terminal name before the first `-'. This |
| allows `sun' to match both `sun' and `sun-cmd', for instance. |
| |
| `application' |
| The APPLICATION construct is used to include |
| application-specific settings. Each program using the |
| Readline library sets the APPLICATION NAME, and you can test |
| for a particular value. This could be used to bind key |
| sequences to functions useful for a specific program. For |
| instance, the following command adds a key sequence that |
| quotes the current or previous word in Bash: |
| $if Bash |
| # Quote the current or previous word |
| "\C-xq": "\eb\"\ef\"" |
| $endif |
| |
| `$endif' |
| This command, as seen in the previous example, terminates an `$if' |
| command. |
| |
| `$else' |
| Commands in this branch of the `$if' directive are executed if the |
| test fails. |
| |
| `$include' |
| This directive takes a single filename as an argument and reads |
| commands and bindings from that file. For example, the following |
| directive reads from `/etc/inputrc': |
| $include /etc/inputrc |
| |
| |
| File: gdb.info, Node: Sample Init File, Prev: Conditional Init Constructs, Up: Readline Init File |
| |
| 32.3.3 Sample Init File |
| ----------------------- |
| |
| Here is an example of an INPUTRC file. This illustrates key binding, |
| variable assignment, and conditional syntax. |
| |
| |
| # This file controls the behaviour of line input editing for |
| # programs that use the GNU Readline library. Existing |
| # programs include FTP, Bash, and GDB. |
| # |
| # You can re-read the inputrc file with C-x C-r. |
| # Lines beginning with '#' are comments. |
| # |
| # First, include any systemwide bindings and variable |
| # assignments from /etc/Inputrc |
| $include /etc/Inputrc |
| |
| # |
| # Set various bindings for emacs mode. |
| |
| set editing-mode emacs |
| |
| $if mode=emacs |
| |
| Meta-Control-h: backward-kill-word Text after the function name is ignored |
| |
| # |
| # Arrow keys in keypad mode |
| # |
| #"\M-OD": backward-char |
| #"\M-OC": forward-char |
| #"\M-OA": previous-history |
| #"\M-OB": next-history |
| # |
| # Arrow keys in ANSI mode |
| # |
| "\M-[D": backward-char |
| "\M-[C": forward-char |
| "\M-[A": previous-history |
| "\M-[B": next-history |
| # |
| # Arrow keys in 8 bit keypad mode |
| # |
| #"\M-\C-OD": backward-char |
| #"\M-\C-OC": forward-char |
| #"\M-\C-OA": previous-history |
| #"\M-\C-OB": next-history |
| # |
| # Arrow keys in 8 bit ANSI mode |
| # |
| #"\M-\C-[D": backward-char |
| #"\M-\C-[C": forward-char |
| #"\M-\C-[A": previous-history |
| #"\M-\C-[B": next-history |
| |
| C-q: quoted-insert |
| |
| $endif |
| |
| # An old-style binding. This happens to be the default. |
| TAB: complete |
| |
| # Macros that are convenient for shell interaction |
| $if Bash |
| # edit the path |
| "\C-xp": "PATH=${PATH}\e\C-e\C-a\ef\C-f" |
| # prepare to type a quoted word -- |
| # insert open and close double quotes |
| # and move to just after the open quote |
| "\C-x\"": "\"\"\C-b" |
| # insert a backslash (testing backslash escapes |
| # in sequences and macros) |
| "\C-x\\": "\\" |
| # Quote the current or previous word |
| "\C-xq": "\eb\"\ef\"" |
| # Add a binding to refresh the line, which is unbound |
| "\C-xr": redraw-current-line |
| # Edit variable on current line. |
| "\M-\C-v": "\C-a\C-k$\C-y\M-\C-e\C-a\C-y=" |
| $endif |
| |
| # use a visible bell if one is available |
| set bell-style visible |
| |
| # don't strip characters to 7 bits when reading |
| set input-meta on |
| |
| # allow iso-latin1 characters to be inserted rather |
| # than converted to prefix-meta sequences |
| set convert-meta off |
| |
| # display characters with the eighth bit set directly |
| # rather than as meta-prefixed characters |
| set output-meta on |
| |
| # if there are more than 150 possible completions for |
| # a word, ask the user if he wants to see all of them |
| set completion-query-items 150 |
| |
| # For FTP |
| $if Ftp |
| "\C-xg": "get \M-?" |
| "\C-xt": "put \M-?" |
| "\M-.": yank-last-arg |
| $endif |
| |
| |
| File: gdb.info, Node: Bindable Readline Commands, Next: Readline vi Mode, Prev: Readline Init File, Up: Command Line Editing |
| |
| 32.4 Bindable Readline Commands |
| =============================== |
| |
| * Menu: |
| |
| * Commands For Moving:: Moving about the line. |
| * Commands For History:: Getting at previous lines. |
| * Commands For Text:: Commands for changing text. |
| * Commands For Killing:: Commands for killing and yanking. |
| * Numeric Arguments:: Specifying numeric arguments, repeat counts. |
| * Commands For Completion:: Getting Readline to do the typing for you. |
| * Keyboard Macros:: Saving and re-executing typed characters |
| * Miscellaneous Commands:: Other miscellaneous commands. |
| |
| This section describes Readline commands that may be bound to key |
| sequences. Command names without an accompanying key sequence are |
| unbound by default. |
| |
| In the following descriptions, "point" refers to the current cursor |
| position, and "mark" refers to a cursor position saved by the |
| `set-mark' command. The text between the point and mark is referred to |
| as the "region". |
| |
| |
| File: gdb.info, Node: Commands For Moving, Next: Commands For History, Up: Bindable Readline Commands |
| |
| 32.4.1 Commands For Moving |
| -------------------------- |
| |
| `beginning-of-line (C-a)' |
| Move to the start of the current line. |
| |
| `end-of-line (C-e)' |
| Move to the end of the line. |
| |
| `forward-char (C-f)' |
| Move forward a character. |
| |
| `backward-char (C-b)' |
| Move back a character. |
| |
| `forward-word (M-f)' |
| Move forward to the end of the next word. Words are composed of |
| letters and digits. |
| |
| `backward-word (M-b)' |
| Move back to the start of the current or previous word. Words are |
| composed of letters and digits. |
| |
| `clear-screen (C-l)' |
| Clear the screen and redraw the current line, leaving the current |
| line at the top of the screen. |
| |
| `redraw-current-line ()' |
| Refresh the current line. By default, this is unbound. |
| |
| |
| |
| File: gdb.info, Node: Commands For History, Next: Commands For Text, Prev: Commands For Moving, Up: Bindable Readline Commands |
| |
| 32.4.2 Commands For Manipulating The History |
| -------------------------------------------- |
| |
| `accept-line (Newline or Return)' |
| Accept the line regardless of where the cursor is. If this line is |
| non-empty, it may be added to the history list for future recall |
| with `add_history()'. If this line is a modified history line, |
| the history line is restored to its original state. |
| |
| `previous-history (C-p)' |
| Move `back' through the history list, fetching the previous |
| command. |
| |
| `next-history (C-n)' |
| Move `forward' through the history list, fetching the next command. |
| |
| `beginning-of-history (M-<)' |
| Move to the first line in the history. |
| |
| `end-of-history (M->)' |
| Move to the end of the input history, i.e., the line currently |
| being entered. |
| |
| `reverse-search-history (C-r)' |
| Search backward starting at the current line and moving `up' |
| through the history as necessary. This is an incremental search. |
| |
| `forward-search-history (C-s)' |
| Search forward starting at the current line and moving `down' |
| through the the history as necessary. This is an incremental |
| search. |
| |
| `non-incremental-reverse-search-history (M-p)' |
| Search backward starting at the current line and moving `up' |
| through the history as necessary using a non-incremental search |
| for a string supplied by the user. |
| |
| `non-incremental-forward-search-history (M-n)' |
| Search forward starting at the current line and moving `down' |
| through the the history as necessary using a non-incremental search |
| for a string supplied by the user. |
| |
| `history-search-forward ()' |
| Search forward through the history for the string of characters |
| between the start of the current line and the point. This is a |
| non-incremental search. By default, this command is unbound. |
| |
| `history-search-backward ()' |
| Search backward through the history for the string of characters |
| between the start of the current line and the point. This is a |
| non-incremental search. By default, this command is unbound. |
| |
| `yank-nth-arg (M-C-y)' |
| Insert the first argument to the previous command (usually the |
| second word on the previous line) at point. With an argument N, |
| insert the Nth word from the previous command (the words in the |
| previous command begin with word 0). A negative argument inserts |
| the Nth word from the end of the previous command. Once the |
| argument N is computed, the argument is extracted as if the `!N' |
| history expansion had been specified. |
| |
| `yank-last-arg (M-. or M-_)' |
| Insert last argument to the previous command (the last word of the |
| previous history entry). With a numeric argument, behave exactly |
| like `yank-nth-arg'. Successive calls to `yank-last-arg' move |
| back through the history list, inserting the last word (or the |
| word specified by the argument to the first call) of each line in |
| turn. Any numeric argument supplied to these successive calls |
| determines the direction to move through the history. A negative |
| argument switches the direction through the history (back or |
| forward). The history expansion facilities are used to extract |
| the last argument, as if the `!$' history expansion had been |
| specified. |
| |
| |
| |
| File: gdb.info, Node: Commands For Text, Next: Commands For Killing, Prev: Commands For History, Up: Bindable Readline Commands |
| |
| 32.4.3 Commands For Changing Text |
| --------------------------------- |
| |
| `delete-char (C-d)' |
| Delete the character at point. If point is at the beginning of |
| the line, there are no characters in the line, and the last |
| character typed was not bound to `delete-char', then return EOF. |
| |
| `backward-delete-char (Rubout)' |
| Delete the character behind the cursor. A numeric argument means |
| to kill the characters instead of deleting them. |
| |
| `forward-backward-delete-char ()' |
| Delete the character under the cursor, unless the cursor is at the |
| end of the line, in which case the character behind the cursor is |
| deleted. By default, this is not bound to a key. |
| |
| `quoted-insert (C-q or C-v)' |
| Add the next character typed to the line verbatim. This is how to |
| insert key sequences like `C-q', for example. |
| |
| `tab-insert (M-<TAB>)' |
| Insert a tab character. |
| |
| `self-insert (a, b, A, 1, !, ...)' |
| Insert yourself. |
| |
| `transpose-chars (C-t)' |
| Drag the character before the cursor forward over the character at |
| the cursor, moving the cursor forward as well. If the insertion |
| point is at the end of the line, then this transposes the last two |
| characters of the line. Negative arguments have no effect. |
| |
| `transpose-words (M-t)' |
| Drag the word before point past the word after point, moving point |
| past that word as well. If the insertion point is at the end of |
| the line, this transposes the last two words on the line. |
| |
| `upcase-word (M-u)' |
| Uppercase the current (or following) word. With a negative |
| argument, uppercase the previous word, but do not move the cursor. |
| |
| `downcase-word (M-l)' |
| Lowercase the current (or following) word. With a negative |
| argument, lowercase the previous word, but do not move the cursor. |
| |
| `capitalize-word (M-c)' |
| Capitalize the current (or following) word. With a negative |
| argument, capitalize the previous word, but do not move the cursor. |
| |
| `overwrite-mode ()' |
| Toggle overwrite mode. With an explicit positive numeric argument, |
| switches to overwrite mode. With an explicit non-positive numeric |
| argument, switches to insert mode. This command affects only |
| `emacs' mode; `vi' mode does overwrite differently. Each call to |
| `readline()' starts in insert mode. |
| |
| In overwrite mode, characters bound to `self-insert' replace the |
| text at point rather than pushing the text to the right. |
| Characters bound to `backward-delete-char' replace the character |
| before point with a space. |
| |
| By default, this command is unbound. |
| |
| |
| |
| File: gdb.info, Node: Commands For Killing, Next: Numeric Arguments, Prev: Commands For Text, Up: Bindable Readline Commands |
| |
| 32.4.4 Killing And Yanking |
| -------------------------- |
| |
| `kill-line (C-k)' |
| Kill the text from point to the end of the line. |
| |
| `backward-kill-line (C-x Rubout)' |
| Kill backward to the beginning of the line. |
| |
| `unix-line-discard (C-u)' |
| Kill backward from the cursor to the beginning of the current line. |
| |
| `kill-whole-line ()' |
| Kill all characters on the current line, no matter where point is. |
| By default, this is unbound. |
| |
| `kill-word (M-d)' |
| Kill from point to the end of the current word, or if between |
| words, to the end of the next word. Word boundaries are the same |
| as `forward-word'. |
| |
| `backward-kill-word (M-<DEL>)' |
| Kill the word behind point. Word boundaries are the same as |
| `backward-word'. |
| |
| `unix-word-rubout (C-w)' |
| Kill the word behind point, using white space as a word boundary. |
| The killed text is saved on the kill-ring. |
| |
| `unix-filename-rubout ()' |
| Kill the word behind point, using white space and the slash |
| character as the word boundaries. The killed text is saved on the |
| kill-ring. |
| |
| `delete-horizontal-space ()' |
| Delete all spaces and tabs around point. By default, this is |
| unbound. |
| |
| `kill-region ()' |
| Kill the text in the current region. By default, this command is |
| unbound. |
| |
| `copy-region-as-kill ()' |
| Copy the text in the region to the kill buffer, so it can be yanked |
| right away. By default, this command is unbound. |
| |
| `copy-backward-word ()' |
| Copy the word before point to the kill buffer. The word |
| boundaries are the same as `backward-word'. By default, this |
| command is unbound. |
| |
| `copy-forward-word ()' |
| Copy the word following point to the kill buffer. The word |
| boundaries are the same as `forward-word'. By default, this |
| command is unbound. |
| |
| `yank (C-y)' |
| Yank the top of the kill ring into the buffer at point. |
| |
| `yank-pop (M-y)' |
| Rotate the kill-ring, and yank the new top. You can only do this |
| if the prior command is `yank' or `yank-pop'. |
| |
| |
| File: gdb.info, Node: Numeric Arguments, Next: Commands For Completion, Prev: Commands For Killing, Up: Bindable Readline Commands |
| |
| 32.4.5 Specifying Numeric Arguments |
| ----------------------------------- |
| |
| `digit-argument (M-0, M-1, ... M--)' |
| Add this digit to the argument already accumulating, or start a new |
| argument. `M--' starts a negative argument. |
| |
| `universal-argument ()' |
| This is another way to specify an argument. If this command is |
| followed by one or more digits, optionally with a leading minus |
| sign, those digits define the argument. If the command is |
| followed by digits, executing `universal-argument' again ends the |
| numeric argument, but is otherwise ignored. As a special case, if |
| this command is immediately followed by a character that is |
| neither a digit or minus sign, the argument count for the next |
| command is multiplied by four. The argument count is initially |
| one, so executing this function the first time makes the argument |
| count four, a second time makes the argument count sixteen, and so |
| on. By default, this is not bound to a key. |
| |
| |
| File: gdb.info, Node: Commands For Completion, Next: Keyboard Macros, Prev: Numeric Arguments, Up: Bindable Readline Commands |
| |
| 32.4.6 Letting Readline Type For You |
| ------------------------------------ |
| |
| `complete (<TAB>)' |
| Attempt to perform completion on the text before point. The |
| actual completion performed is application-specific. The default |
| is filename completion. |
| |
| `possible-completions (M-?)' |
| List the possible completions of the text before point. When |
| displaying completions, Readline sets the number of columns used |
| for display to the value of `completion-display-width', the value |
| of the environment variable `COLUMNS', or the screen width, in |
| that order. |
| |
| `insert-completions (M-*)' |
| Insert all completions of the text before point that would have |
| been generated by `possible-completions'. |
| |
| `menu-complete ()' |
| Similar to `complete', but replaces the word to be completed with |
| a single match from the list of possible completions. Repeated |
| execution of `menu-complete' steps through the list of possible |
| completions, inserting each match in turn. At the end of the list |
| of completions, the bell is rung (subject to the setting of |
| `bell-style') and the original text is restored. An argument of N |
| moves N positions forward in the list of matches; a negative |
| argument may be used to move backward through the list. This |
| command is intended to be bound to <TAB>, but is unbound by |
| default. |
| |
| `menu-complete-backward ()' |
| Identical to `menu-complete', but moves backward through the list |
| of possible completions, as if `menu-complete' had been given a |
| negative argument. |
| |
| `delete-char-or-list ()' |
| Deletes the character under the cursor if not at the beginning or |
| end of the line (like `delete-char'). If at the end of the line, |
| behaves identically to `possible-completions'. This command is |
| unbound by default. |
| |
| |
| |
| File: gdb.info, Node: Keyboard Macros, Next: Miscellaneous Commands, Prev: Commands For Completion, Up: Bindable Readline Commands |
| |
| 32.4.7 Keyboard Macros |
| ---------------------- |
| |
| `start-kbd-macro (C-x ()' |
| Begin saving the characters typed into the current keyboard macro. |
| |
| `end-kbd-macro (C-x ))' |
| Stop saving the characters typed into the current keyboard macro |
| and save the definition. |
| |
| `call-last-kbd-macro (C-x e)' |
| Re-execute the last keyboard macro defined, by making the |
| characters in the macro appear as if typed at the keyboard. |
| |
| |
| |
| File: gdb.info, Node: Miscellaneous Commands, Prev: Keyboard Macros, Up: Bindable Readline Commands |
| |
| 32.4.8 Some Miscellaneous Commands |
| ---------------------------------- |
| |
| `re-read-init-file (C-x C-r)' |
| Read in the contents of the INPUTRC file, and incorporate any |
| bindings or variable assignments found there. |
| |
| `abort (C-g)' |
| Abort the current editing command and ring the terminal's bell |
| (subject to the setting of `bell-style'). |
| |
| `do-uppercase-version (M-a, M-b, M-X, ...)' |
| If the metafied character X is lowercase, run the command that is |
| bound to the corresponding uppercase character. |
| |
| `prefix-meta (<ESC>)' |
| Metafy the next character typed. This is for keyboards without a |
| meta key. Typing `<ESC> f' is equivalent to typing `M-f'. |
| |
| `undo (C-_ or C-x C-u)' |
| Incremental undo, separately remembered for each line. |
| |
| `revert-line (M-r)' |
| Undo all changes made to this line. This is like executing the |
| `undo' command enough times to get back to the beginning. |
| |
| `tilde-expand (M-~)' |
| Perform tilde expansion on the current word. |
| |
| `set-mark (C-@)' |
| Set the mark to the point. If a numeric argument is supplied, the |
| mark is set to that position. |
| |
| `exchange-point-and-mark (C-x C-x)' |
| Swap the point with the mark. The current cursor position is set |
| to the saved position, and the old cursor position is saved as the |
| mark. |
| |
| `character-search (C-])' |
| A character is read and point is moved to the next occurrence of |
| that character. A negative count searches for previous |
| occurrences. |
| |
| `character-search-backward (M-C-])' |
| A character is read and point is moved to the previous occurrence |
| of that character. A negative count searches for subsequent |
| occurrences. |
| |
| `skip-csi-sequence ()' |
| Read enough characters to consume a multi-key sequence such as |
| those defined for keys like Home and End. Such sequences begin |
| with a Control Sequence Indicator (CSI), usually ESC-[. If this |
| sequence is bound to "\e[", keys producing such sequences will |
| have no effect unless explicitly bound to a readline command, |
| instead of inserting stray characters into the editing buffer. |
| This is unbound by default, but usually bound to ESC-[. |
| |
| `insert-comment (M-#)' |
| Without a numeric argument, the value of the `comment-begin' |
| variable is inserted at the beginning of the current line. If a |
| numeric argument is supplied, this command acts as a toggle: if |
| the characters at the beginning of the line do not match the value |
| of `comment-begin', the value is inserted, otherwise the |
| characters in `comment-begin' are deleted from the beginning of |
| the line. In either case, the line is accepted as if a newline |
| had been typed. |
| |
| `dump-functions ()' |
| Print all of the functions and their key bindings to the Readline |
| output stream. If a numeric argument is supplied, the output is |
| formatted in such a way that it can be made part of an INPUTRC |
| file. This command is unbound by default. |
| |
| `dump-variables ()' |
| Print all of the settable variables and their values to the |
| Readline output stream. If a numeric argument is supplied, the |
| output is formatted in such a way that it can be made part of an |
| INPUTRC file. This command is unbound by default. |
| |
| `dump-macros ()' |
| Print all of the Readline key sequences bound to macros and the |
| strings they output. If a numeric argument is supplied, the |
| output is formatted in such a way that it can be made part of an |
| INPUTRC file. This command is unbound by default. |
| |
| `emacs-editing-mode (C-e)' |
| When in `vi' command mode, this causes a switch to `emacs' editing |
| mode. |
| |
| `vi-editing-mode (M-C-j)' |
| When in `emacs' editing mode, this causes a switch to `vi' editing |
| mode. |
| |
| |
| |
| File: gdb.info, Node: Readline vi Mode, Prev: Bindable Readline Commands, Up: Command Line Editing |
| |
| 32.5 Readline vi Mode |
| ===================== |
| |
| While the Readline library does not have a full set of `vi' editing |
| functions, it does contain enough to allow simple editing of the line. |
| The Readline `vi' mode behaves as specified in the POSIX standard. |
| |
| In order to switch interactively between `emacs' and `vi' editing |
| modes, use the command `M-C-j' (bound to emacs-editing-mode when in |
| `vi' mode and to vi-editing-mode in `emacs' mode). The Readline |
| default is `emacs' mode. |
| |
| When you enter a line in `vi' mode, you are already placed in |
| `insertion' mode, as if you had typed an `i'. Pressing <ESC> switches |
| you into `command' mode, where you can edit the text of the line with |
| the standard `vi' movement keys, move to previous history lines with |
| `k' and subsequent lines with `j', and so forth. |
| |
| |
| File: gdb.info, Node: Using History Interactively, Next: In Memoriam, Prev: Command Line Editing, Up: Top |
| |
| 33 Using History Interactively |
| ****************************** |
| |
| This chapter describes how to use the GNU History Library interactively, |
| from a user's standpoint. It should be considered a user's guide. For |
| information on using the GNU History Library in your own programs, |
| *note Programming with GNU History: (history)Programming with GNU |
| History. |
| |
| * Menu: |
| |
| * History Interaction:: What it feels like using History as a user. |
| |
| |
| File: gdb.info, Node: History Interaction, Up: Using History Interactively |
| |
| 33.1 History Expansion |
| ====================== |
| |
| The History library provides a history expansion feature that is similar |
| to the history expansion provided by `csh'. This section describes the |
| syntax used to manipulate the history information. |
| |
| History expansions introduce words from the history list into the |
| input stream, making it easy to repeat commands, insert the arguments |
| to a previous command into the current input line, or fix errors in |
| previous commands quickly. |
| |
| History expansion takes place in two parts. The first is to |
| determine which line from the history list should be used during |
| substitution. The second is to select portions of that line for |
| inclusion into the current one. The line selected from the history is |
| called the "event", and the portions of that line that are acted upon |
| are called "words". Various "modifiers" are available to manipulate |
| the selected words. The line is broken into words in the same fashion |
| that Bash does, so that several words surrounded by quotes are |
| considered one word. History expansions are introduced by the |
| appearance of the history expansion character, which is `!' by default. |
| |
| * Menu: |
| |
| * Event Designators:: How to specify which history line to use. |
| * Word Designators:: Specifying which words are of interest. |
| * Modifiers:: Modifying the results of substitution. |
| |
| |
| File: gdb.info, Node: Event Designators, Next: Word Designators, Up: History Interaction |
| |
| 33.1.1 Event Designators |
| ------------------------ |
| |
| An event designator is a reference to a command line entry in the |
| history list. Unless the reference is absolute, events are relative to |
| the current position in the history list. |
| |
| `!' |
| Start a history substitution, except when followed by a space, tab, |
| the end of the line, or `='. |
| |
| `!N' |
| Refer to command line N. |
| |
| `!-N' |
| Refer to the command N lines back. |
| |
| `!!' |
| Refer to the previous command. This is a synonym for `!-1'. |
| |
| `!STRING' |
| Refer to the most recent command preceding the current position in |
| the history list starting with STRING. |
| |
| `!?STRING[?]' |
| Refer to the most recent command preceding the current position in |
| the history list containing STRING. The trailing `?' may be |
| omitted if the STRING is followed immediately by a newline. |
| |
| `^STRING1^STRING2^' |
| Quick Substitution. Repeat the last command, replacing STRING1 |
| with STRING2. Equivalent to `!!:s/STRING1/STRING2/'. |
| |
| `!#' |
| The entire command line typed so far. |
| |
| |
| |
| File: gdb.info, Node: Word Designators, Next: Modifiers, Prev: Event Designators, Up: History Interaction |
| |
| 33.1.2 Word Designators |
| ----------------------- |
| |
| Word designators are used to select desired words from the event. A |
| `:' separates the event specification from the word designator. It may |
| be omitted if the word designator begins with a `^', `$', `*', `-', or |
| `%'. Words are numbered from the beginning of the line, with the first |
| word being denoted by 0 (zero). Words are inserted into the current |
| line separated by single spaces. |
| |
| For example, |
| |
| `!!' |
| designates the preceding command. When you type this, the |
| preceding command is repeated in toto. |
| |
| `!!:$' |
| designates the last argument of the preceding command. This may be |
| shortened to `!$'. |
| |
| `!fi:2' |
| designates the second argument of the most recent command starting |
| with the letters `fi'. |
| |
| Here are the word designators: |
| |
| `0 (zero)' |
| The `0'th word. For many applications, this is the command word. |
| |
| `N' |
| The Nth word. |
| |
| `^' |
| The first argument; that is, word 1. |
| |
| `$' |
| The last argument. |
| |
| `%' |
| The word matched by the most recent `?STRING?' search. |
| |
| `X-Y' |
| A range of words; `-Y' abbreviates `0-Y'. |
| |
| `*' |
| All of the words, except the `0'th. This is a synonym for `1-$'. |
| It is not an error to use `*' if there is just one word in the |
| event; the empty string is returned in that case. |
| |
| `X*' |
| Abbreviates `X-$' |
| |
| `X-' |
| Abbreviates `X-$' like `X*', but omits the last word. |
| |
| |
| If a word designator is supplied without an event specification, the |
| previous command is used as the event. |
| |
| |
| File: gdb.info, Node: Modifiers, Prev: Word Designators, Up: History Interaction |
| |
| 33.1.3 Modifiers |
| ---------------- |
| |
| After the optional word designator, you can add a sequence of one or |
| more of the following modifiers, each preceded by a `:'. |
| |
| `h' |
| Remove a trailing pathname component, leaving only the head. |
| |
| `t' |
| Remove all leading pathname components, leaving the tail. |
| |
| `r' |
| Remove a trailing suffix of the form `.SUFFIX', leaving the |
| basename. |
| |
| `e' |
| Remove all but the trailing suffix. |
| |
| `p' |
| Print the new command but do not execute it. |
| |
| `s/OLD/NEW/' |
| Substitute NEW for the first occurrence of OLD in the event line. |
| Any delimiter may be used in place of `/'. The delimiter may be |
| quoted in OLD and NEW with a single backslash. If `&' appears in |
| NEW, it is replaced by OLD. A single backslash will quote the |
| `&'. The final delimiter is optional if it is the last character |
| on the input line. |
| |
| `&' |
| Repeat the previous substitution. |
| |
| `g' |
| `a' |
| Cause changes to be applied over the entire event line. Used in |
| conjunction with `s', as in `gs/OLD/NEW/', or with `&'. |
| |
| `G' |
| Apply the following `s' modifier once to each word in the event. |
| |
| |
| |
| File: gdb.info, Node: In Memoriam, Next: Formatting Documentation, Prev: Using History Interactively, Up: Top |
| |
| Appendix A In Memoriam |
| ********************** |
| |
| The GDB project mourns the loss of the following long-time contributors: |
| |
| `Fred Fish' |
| Fred was a long-standing contributor to GDB (1991-2006), and to |
| Free Software in general. Outside of GDB, he was known in the |
| Amiga world for his series of Fish Disks, and the GeekGadget |
| project. |
| |
| `Michael Snyder' |
| Michael was one of the Global Maintainers of the GDB project, with |
| contributions recorded as early as 1996, until 2011. In addition |
| to his day to day participation, he was a large driving force |
| behind adding Reverse Debugging to GDB. |
| |
| Beyond their technical contributions to the project, they were also |
| enjoyable members of the Free Software Community. We will miss them. |
| |
| |
| File: gdb.info, Node: Formatting Documentation, Next: Installing GDB, Prev: In Memoriam, Up: Top |
| |
| Appendix B Formatting Documentation |
| *********************************** |
| |
| The GDB 4 release includes an already-formatted reference card, ready |
| for printing with PostScript or Ghostscript, in the `gdb' subdirectory |
| of the main source directory(1). If you can use PostScript or |
| Ghostscript with your printer, you can print the reference card |
| immediately with `refcard.ps'. |
| |
| The release also includes the source for the reference card. You |
| can format it, using TeX, by typing: |
| |
| make refcard.dvi |
| |
| The GDB reference card is designed to print in "landscape" mode on |
| US "letter" size paper; that is, on a sheet 11 inches wide by 8.5 inches |
| high. You will need to specify this form of printing as an option to |
| your DVI output program. |
| |
| All the documentation for GDB comes as part of the machine-readable |
| distribution. The documentation is written in Texinfo format, which is |
| a documentation system that uses a single source file to produce both |
| on-line information and a printed manual. You can use one of the Info |
| formatting commands to create the on-line version of the documentation |
| and TeX (or `texi2roff') to typeset the printed version. |
| |
| GDB includes an already formatted copy of the on-line Info version |
| of this manual in the `gdb' subdirectory. The main Info file is |
| `gdb-7.6.50.20131211-cvs/gdb/gdb.info', and it refers to subordinate |
| files matching `gdb.info*' in the same directory. If necessary, you |
| can print out these files, or read them with any editor; but they are |
| easier to read using the `info' subsystem in GNU Emacs or the |
| standalone `info' program, available as part of the GNU Texinfo |
| distribution. |
| |
| If you want to format these Info files yourself, you need one of the |
| Info formatting programs, such as `texinfo-format-buffer' or `makeinfo'. |
| |
| If you have `makeinfo' installed, and are in the top level GDB |
| source directory (`gdb-7.6.50.20131211-cvs', in the case of version |
| 7.6.50.20131211-cvs), you can make the Info file by typing: |
| |
| cd gdb |
| make gdb.info |
| |
| If you want to typeset and print copies of this manual, you need TeX, |
| a program to print its DVI output files, and `texinfo.tex', the Texinfo |
| definitions file. |
| |
| TeX is a typesetting program; it does not print files directly, but |
| produces output files called DVI files. To print a typeset document, |
| you need a program to print DVI files. If your system has TeX |
| installed, chances are it has such a program. The precise command to |
| use depends on your system; `lpr -d' is common; another (for PostScript |
| devices) is `dvips'. The DVI print command may require a file name |
| without any extension or a `.dvi' extension. |
| |
| TeX also requires a macro definitions file called `texinfo.tex'. |
| This file tells TeX how to typeset a document written in Texinfo |
| format. On its own, TeX cannot either read or typeset a Texinfo file. |
| `texinfo.tex' is distributed with GDB and is located in the |
| `gdb-VERSION-NUMBER/texinfo' directory. |
| |
| If you have TeX and a DVI printer program installed, you can typeset |
| and print this manual. First switch to the `gdb' subdirectory of the |
| main source directory (for example, to `gdb-7.6.50.20131211-cvs/gdb') |
| and type: |
| |
| make gdb.dvi |
| |
| Then give `gdb.dvi' to your DVI printing program. |
| |
| ---------- Footnotes ---------- |
| |
| (1) In `gdb-7.6.50.20131211-cvs/gdb/refcard.ps' of the version |
| 7.6.50.20131211-cvs release. |
| |
| |
| File: gdb.info, Node: Installing GDB, Next: Maintenance Commands, Prev: Formatting Documentation, Up: Top |
| |
| Appendix C Installing GDB |
| ************************* |
| |
| * Menu: |
| |
| * Requirements:: Requirements for building GDB |
| * Running Configure:: Invoking the GDB `configure' script |
| * Separate Objdir:: Compiling GDB in another directory |
| * Config Names:: Specifying names for hosts and targets |
| * Configure Options:: Summary of options for configure |
| * System-wide configuration:: Having a system-wide init file |
| |
| |
| File: gdb.info, Node: Requirements, Next: Running Configure, Up: Installing GDB |
| |
| C.1 Requirements for Building GDB |
| ================================= |
| |
| Building GDB requires various tools and packages to be available. |
| Other packages will be used only if they are found. |
| |
| Tools/Packages Necessary for Building GDB |
| ========================================= |
| |
| ISO C90 compiler |
| GDB is written in ISO C90. It should be buildable with any |
| working C90 compiler, e.g. GCC. |
| |
| |
| Tools/Packages Optional for Building GDB |
| ======================================== |
| |
| Expat |
| GDB can use the Expat XML parsing library. This library may be |
| included with your operating system distribution; if it is not, you |
| can get the latest version from `http://expat.sourceforge.net'. |
| The `configure' script will search for this library in several |
| standard locations; if it is installed in an unusual path, you can |
| use the `--with-libexpat-prefix' option to specify its location. |
| |
| Expat is used for: |
| |
| * Remote protocol memory maps (*note Memory Map Format::) |
| |
| * Target descriptions (*note Target Descriptions::) |
| |
| * Remote shared library lists (*Note Library List Format::, or |
| alternatively *note Library List Format for SVR4 Targets::) |
| |
| * MS-Windows shared libraries (*note Shared Libraries::) |
| |
| * Traceframe info (*note Traceframe Info Format::) |
| |
| * Branch trace (*note Branch Trace Format::) |
| |
| zlib |
| GDB will use the `zlib' library, if available, to read compressed |
| debug sections. Some linkers, such as GNU gold, are capable of |
| producing binaries with compressed debug sections. If GDB is |
| compiled with `zlib', it will be able to read the debug |
| information in such binaries. |
| |
| The `zlib' library is likely included with your operating system |
| distribution; if it is not, you can get the latest version from |
| `http://zlib.net'. |
| |
| iconv |
| GDB's features related to character sets (*note Character Sets::) |
| require a functioning `iconv' implementation. If you are on a GNU |
| system, then this is provided by the GNU C Library. Some other |
| systems also provide a working `iconv'. |
| |
| If GDB is using the `iconv' program which is installed in a |
| non-standard place, you will need to tell GDB where to find it. |
| This is done with `--with-iconv-bin' which specifies the directory |
| that contains the `iconv' program. |
| |
| On systems without `iconv', you can install GNU Libiconv. If you |
| have previously installed Libiconv, you can use the |
| `--with-libiconv-prefix' option to configure. |
| |
| GDB's top-level `configure' and `Makefile' will arrange to build |
| Libiconv if a directory named `libiconv' appears in the top-most |
| source directory. If Libiconv is built this way, and if the |
| operating system does not provide a suitable `iconv' |
| implementation, then the just-built library will automatically be |
| used by GDB. One easy way to set this up is to download GNU |
| Libiconv, unpack it, and then rename the directory holding the |
| Libiconv source code to `libiconv'. |
| |
| |
| File: gdb.info, Node: Running Configure, Next: Separate Objdir, Prev: Requirements, Up: Installing GDB |
| |
| C.2 Invoking the GDB `configure' Script |
| ======================================= |
| |
| GDB comes with a `configure' script that automates the process of |
| preparing GDB for installation; you can then use `make' to build the |
| `gdb' program. |
| |
| The GDB distribution includes all the source code you need for GDB |
| in a single directory, whose name is usually composed by appending the |
| version number to `gdb'. |
| |
| For example, the GDB version 7.6.50.20131211-cvs distribution is in |
| the `gdb-7.6.50.20131211-cvs' directory. That directory contains: |
| |
| `gdb-7.6.50.20131211-cvs/configure (and supporting files)' |
| script for configuring GDB and all its supporting libraries |
| |
| `gdb-7.6.50.20131211-cvs/gdb' |
| the source specific to GDB itself |
| |
| `gdb-7.6.50.20131211-cvs/bfd' |
| source for the Binary File Descriptor library |
| |
| `gdb-7.6.50.20131211-cvs/include' |
| GNU include files |
| |
| `gdb-7.6.50.20131211-cvs/libiberty' |
| source for the `-liberty' free software library |
| |
| `gdb-7.6.50.20131211-cvs/opcodes' |
| source for the library of opcode tables and disassemblers |
| |
| `gdb-7.6.50.20131211-cvs/readline' |
| source for the GNU command-line interface |
| |
| `gdb-7.6.50.20131211-cvs/glob' |
| source for the GNU filename pattern-matching subroutine |
| |
| `gdb-7.6.50.20131211-cvs/mmalloc' |
| source for the GNU memory-mapped malloc package |
| |
| The simplest way to configure and build GDB is to run `configure' |
| from the `gdb-VERSION-NUMBER' source directory, which in this example |
| is the `gdb-7.6.50.20131211-cvs' directory. |
| |
| First switch to the `gdb-VERSION-NUMBER' source directory if you are |
| not already in it; then run `configure'. Pass the identifier for the |
| platform on which GDB will run as an argument. |
| |
| For example: |
| |
| cd gdb-7.6.50.20131211-cvs |
| ./configure HOST |
| make |
| |
| where HOST is an identifier such as `sun4' or `decstation', that |
| identifies the platform where GDB will run. (You can often leave off |
| HOST; `configure' tries to guess the correct value by examining your |
| system.) |
| |
| Running `configure HOST' and then running `make' builds the `bfd', |
| `readline', `mmalloc', and `libiberty' libraries, then `gdb' itself. |
| The configured source files, and the binaries, are left in the |
| corresponding source directories. |
| |
| `configure' is a Bourne-shell (`/bin/sh') script; if your system |
| does not recognize this automatically when you run a different shell, |
| you may need to run `sh' on it explicitly: |
| |
| sh configure HOST |
| |
| If you run `configure' from a directory that contains source |
| directories for multiple libraries or programs, such as the |
| `gdb-7.6.50.20131211-cvs' source directory for version |
| 7.6.50.20131211-cvs, `configure' creates configuration files for every |
| directory level underneath (unless you tell it not to, with the |
| `--norecursion' option). |
| |
| You should run the `configure' script from the top directory in the |
| source tree, the `gdb-VERSION-NUMBER' directory. If you run |
| `configure' from one of the subdirectories, you will configure only |
| that subdirectory. That is usually not what you want. In particular, |
| if you run the first `configure' from the `gdb' subdirectory of the |
| `gdb-VERSION-NUMBER' directory, you will omit the configuration of |
| `bfd', `readline', and other sibling directories of the `gdb' |
| subdirectory. This leads to build errors about missing include files |
| such as `bfd/bfd.h'. |
| |
| You can install `gdb' anywhere; it has no hardwired paths. However, |
| you should make sure that the shell on your path (named by the `SHELL' |
| environment variable) is publicly readable. Remember that GDB uses the |
| shell to start your program--some systems refuse to let GDB debug child |
| processes whose programs are not readable. |
| |
| |
| File: gdb.info, Node: Separate Objdir, Next: Config Names, Prev: Running Configure, Up: Installing GDB |
| |
| C.3 Compiling GDB in Another Directory |
| ====================================== |
| |
| If you want to run GDB versions for several host or target machines, |
| you need a different `gdb' compiled for each combination of host and |
| target. `configure' is designed to make this easy by allowing you to |
| generate each configuration in a separate subdirectory, rather than in |
| the source directory. If your `make' program handles the `VPATH' |
| feature (GNU `make' does), running `make' in each of these directories |
| builds the `gdb' program specified there. |
| |
| To build `gdb' in a separate directory, run `configure' with the |
| `--srcdir' option to specify where to find the source. (You also need |
| to specify a path to find `configure' itself from your working |
| directory. If the path to `configure' would be the same as the |
| argument to `--srcdir', you can leave out the `--srcdir' option; it is |
| assumed.) |
| |
| For example, with version 7.6.50.20131211-cvs, you can build GDB in a |
| separate directory for a Sun 4 like this: |
| |
| cd gdb-7.6.50.20131211-cvs |
| mkdir ../gdb-sun4 |
| cd ../gdb-sun4 |
| ../gdb-7.6.50.20131211-cvs/configure sun4 |
| make |
| |
| When `configure' builds a configuration using a remote source |
| directory, it creates a tree for the binaries with the same structure |
| (and using the same names) as the tree under the source directory. In |
| the example, you'd find the Sun 4 library `libiberty.a' in the |
| directory `gdb-sun4/libiberty', and GDB itself in `gdb-sun4/gdb'. |
| |
| Make sure that your path to the `configure' script has just one |
| instance of `gdb' in it. If your path to `configure' looks like |
| `../gdb-7.6.50.20131211-cvs/gdb/configure', you are configuring only |
| one subdirectory of GDB, not the whole package. This leads to build |
| errors about missing include files such as `bfd/bfd.h'. |
| |
| One popular reason to build several GDB configurations in separate |
| directories is to configure GDB for cross-compiling (where GDB runs on |
| one machine--the "host"--while debugging programs that run on another |
| machine--the "target"). You specify a cross-debugging target by giving |
| the `--target=TARGET' option to `configure'. |
| |
| When you run `make' to build a program or library, you must run it |
| in a configured directory--whatever directory you were in when you |
| called `configure' (or one of its subdirectories). |
| |
| The `Makefile' that `configure' generates in each source directory |
| also runs recursively. If you type `make' in a source directory such |
| as `gdb-7.6.50.20131211-cvs' (or in a separate configured directory |
| configured with `--srcdir=DIRNAME/gdb-7.6.50.20131211-cvs'), you will |
| build all the required libraries, and then build GDB. |
| |
| When you have multiple hosts or targets configured in separate |
| directories, you can run `make' on them in parallel (for example, if |
| they are NFS-mounted on each of the hosts); they will not interfere |
| with each other. |
| |
| |
| File: gdb.info, Node: Config Names, Next: Configure Options, Prev: Separate Objdir, Up: Installing GDB |
| |
| C.4 Specifying Names for Hosts and Targets |
| ========================================== |
| |
| The specifications used for hosts and targets in the `configure' script |
| are based on a three-part naming scheme, but some short predefined |
| aliases are also supported. The full naming scheme encodes three pieces |
| of information in the following pattern: |
| |
| ARCHITECTURE-VENDOR-OS |
| |
| For example, you can use the alias `sun4' as a HOST argument, or as |
| the value for TARGET in a `--target=TARGET' option. The equivalent |
| full name is `sparc-sun-sunos4'. |
| |
| The `configure' script accompanying GDB does not provide any query |
| facility to list all supported host and target names or aliases. |
| `configure' calls the Bourne shell script `config.sub' to map |
| abbreviations to full names; you can read the script, if you wish, or |
| you can use it to test your guesses on abbreviations--for example: |
| |
| % sh config.sub i386-linux |
| i386-pc-linux-gnu |
| % sh config.sub alpha-linux |
| alpha-unknown-linux-gnu |
| % sh config.sub hp9k700 |
| hppa1.1-hp-hpux |
| % sh config.sub sun4 |
| sparc-sun-sunos4.1.1 |
| % sh config.sub sun3 |
| m68k-sun-sunos4.1.1 |
| % sh config.sub i986v |
| Invalid configuration `i986v': machine `i986v' not recognized |
| |
| `config.sub' is also distributed in the GDB source directory |
| (`gdb-7.6.50.20131211-cvs', for version 7.6.50.20131211-cvs). |
| |
| |
| File: gdb.info, Node: Configure Options, Next: System-wide configuration, Prev: Config Names, Up: Installing GDB |
| |
| C.5 `configure' Options |
| ======================= |
| |
| Here is a summary of the `configure' options and arguments that are |
| most often useful for building GDB. `configure' also has several other |
| options not listed here. *note (configure.info)What Configure Does::, |
| for a full explanation of `configure'. |
| |
| configure [--help] |
| [--prefix=DIR] |
| [--exec-prefix=DIR] |
| [--srcdir=DIRNAME] |
| [--norecursion] [--rm] |
| [--target=TARGET] |
| HOST |
| |
| You may introduce options with a single `-' rather than `--' if you |
| prefer; but you may abbreviate option names if you use `--'. |
| |
| `--help' |
| Display a quick summary of how to invoke `configure'. |
| |
| `--prefix=DIR' |
| Configure the source to install programs and files under directory |
| `DIR'. |
| |
| `--exec-prefix=DIR' |
| Configure the source to install programs under directory `DIR'. |
| |
| `--srcdir=DIRNAME' |
| *Warning: using this option requires GNU `make', or another `make' |
| that implements the `VPATH' feature.* |
| Use this option to make configurations in directories separate |
| from the GDB source directories. Among other things, you can use |
| this to build (or maintain) several configurations simultaneously, |
| in separate directories. `configure' writes |
| configuration-specific files in the current directory, but |
| arranges for them to use the source in the directory DIRNAME. |
| `configure' creates directories under the working directory in |
| parallel to the source directories below DIRNAME. |
| |
| `--norecursion' |
| Configure only the directory level where `configure' is executed; |
| do not propagate configuration to subdirectories. |
| |
| `--target=TARGET' |
| Configure GDB for cross-debugging programs running on the specified |
| TARGET. Without this option, GDB is configured to debug programs |
| that run on the same machine (HOST) as GDB itself. |
| |
| There is no convenient way to generate a list of all available |
| targets. |
| |
| `HOST ...' |
| Configure GDB to run on the specified HOST. |
| |
| There is no convenient way to generate a list of all available |
| hosts. |
| |
| There are many other options available as well, but they are |
| generally needed for special purposes only. |
| |
| |
| File: gdb.info, Node: System-wide configuration, Prev: Configure Options, Up: Installing GDB |
| |
| C.6 System-wide configuration and settings |
| ========================================== |
| |
| GDB can be configured to have a system-wide init file; this file will |
| be read and executed at startup (*note What GDB does during startup: |
| Startup.). |
| |
| Here is the corresponding configure option: |
| |
| `--with-system-gdbinit=FILE' |
| Specify that the default location of the system-wide init file is |
| FILE. |
| |
| If GDB has been configured with the option `--prefix=$prefix', it |
| may be subject to relocation. Two possible cases: |
| |
| * If the default location of this init file contains `$prefix', it |
| will be subject to relocation. Suppose that the configure options |
| are `--prefix=$prefix --with-system-gdbinit=$prefix/etc/gdbinit'; |
| if GDB is moved from `$prefix' to `$install', the system init file |
| is looked for as `$install/etc/gdbinit' instead of |
| `$prefix/etc/gdbinit'. |
| |
| * By contrast, if the default location does not contain the prefix, |
| it will not be relocated. E.g. if GDB has been configured with |
| `--prefix=/usr/local --with-system-gdbinit=/usr/share/gdb/gdbinit', |
| then GDB will always look for `/usr/share/gdb/gdbinit', wherever |
| GDB is installed. |
| |
| If the configured location of the system-wide init file (as given by |
| the `--with-system-gdbinit' option at configure time) is in the |
| data-directory (as specified by `--with-gdb-datadir' at configure time) |
| or in one of its subdirectories, then GDB will look for the system-wide |
| init file in the directory specified by the `--data-directory' |
| command-line option. Note that the system-wide init file is only read |
| once, during GDB initialization. If the data-directory is changed |
| after GDB has started with the `set data-directory' command, the file |
| will not be reread. |
| |
| * Menu: |
| |
| * System-wide Configuration Scripts:: Installed System-wide Configuration Scripts |
| |
| |
| File: gdb.info, Node: System-wide Configuration Scripts, Up: System-wide configuration |
| |
| C.6.1 Installed System-wide Configuration Scripts |
| ------------------------------------------------- |
| |
| The `system-gdbinit' directory, located inside the data-directory (as |
| specified by `--with-gdb-datadir' at configure time) contains a number |
| of scripts which can be used as system-wide init files. To |
| automatically source those scripts at startup, GDB should be configured |
| with `--with-system-gdbinit'. Otherwise, any user should be able to |
| source them by hand as needed. |
| |
| The following scripts are currently available: |
| * `elinos.py' This script is useful when debugging a program on an |
| ELinOS target. It takes advantage of the environment variables |
| defined in a standard ELinOS environment in order to determine the |
| location of the system shared libraries, and then sets the |
| `solib-absolute-prefix' and `solib-search-path' variables |
| appropriately. |
| |
| * `wrs-linux.py' This script is useful when debugging a program on a |
| target running Wind River Linux. It expects the `ENV_PREFIX' to |
| be set to the host-side sysroot used by the target system. |
| |
| |
| |
| File: gdb.info, Node: Maintenance Commands, Next: Remote Protocol, Prev: Installing GDB, Up: Top |
| |
| Appendix D Maintenance Commands |
| ******************************* |
| |
| In addition to commands intended for GDB users, GDB includes a number |
| of commands intended for GDB developers, that are not documented |
| elsewhere in this manual. These commands are provided here for |
| reference. (For commands that turn on debugging messages, see *note |
| Debugging Output::.) |
| |
| `maint agent [-at LOCATION,] EXPRESSION' |
| `maint agent-eval [-at LOCATION,] EXPRESSION' |
| Translate the given EXPRESSION into remote agent bytecodes. This |
| command is useful for debugging the Agent Expression mechanism |
| (*note Agent Expressions::). The `agent' version produces an |
| expression useful for data collection, such as by tracepoints, |
| while `maint agent-eval' produces an expression that evaluates |
| directly to a result. For instance, a collection expression for |
| `globa + globb' will include bytecodes to record four bytes of |
| memory at each of the addresses of `globa' and `globb', while |
| discarding the result of the addition, while an evaluation |
| expression will do the addition and return the sum. If `-at' is |
| given, generate remote agent bytecode for LOCATION. If not, |
| generate remote agent bytecode for current frame PC address. |
| |
| `maint agent-printf FORMAT,EXPR,...' |
| Translate the given format string and list of argument expressions |
| into remote agent bytecodes and display them as a disassembled |
| list. This command is useful for debugging the agent version of |
| dynamic printf (*note Dynamic Printf::). |
| |
| `maint info breakpoints' |
| Using the same format as `info breakpoints', display both the |
| breakpoints you've set explicitly, and those GDB is using for |
| internal purposes. Internal breakpoints are shown with negative |
| breakpoint numbers. The type column identifies what kind of |
| breakpoint is shown: |
| |
| `breakpoint' |
| Normal, explicitly set breakpoint. |
| |
| `watchpoint' |
| Normal, explicitly set watchpoint. |
| |
| `longjmp' |
| Internal breakpoint, used to handle correctly stepping through |
| `longjmp' calls. |
| |
| `longjmp resume' |
| Internal breakpoint at the target of a `longjmp'. |
| |
| `until' |
| Temporary internal breakpoint used by the GDB `until' command. |
| |
| `finish' |
| Temporary internal breakpoint used by the GDB `finish' |
| command. |
| |
| `shlib events' |
| Shared library events. |
| |
| |
| `maint info bfds' |
| This prints information about each `bfd' object that is known to |
| GDB. *Note BFD: (bfd)Top. |
| |
| `set displaced-stepping' |
| `show displaced-stepping' |
| Control whether or not GDB will do "displaced stepping" if the |
| target supports it. Displaced stepping is a way to single-step |
| over breakpoints without removing them from the inferior, by |
| executing an out-of-line copy of the instruction that was |
| originally at the breakpoint location. It is also known as |
| out-of-line single-stepping. |
| |
| `set displaced-stepping on' |
| If the target architecture supports it, GDB will use |
| displaced stepping to step over breakpoints. |
| |
| `set displaced-stepping off' |
| GDB will not use displaced stepping to step over breakpoints, |
| even if such is supported by the target architecture. |
| |
| `set displaced-stepping auto' |
| This is the default mode. GDB will use displaced stepping |
| only if non-stop mode is active (*note Non-Stop Mode::) and |
| the target architecture supports displaced stepping. |
| |
| `maint check-psymtabs' |
| Check the consistency of currently expanded psymtabs versus |
| symtabs. Use this to check, for example, whether a symbol is in |
| one but not the other. |
| |
| `maint check-symtabs' |
| Check the consistency of currently expanded symtabs. |
| |
| `maint expand-symtabs [REGEXP]' |
| Expand symbol tables. If REGEXP is specified, only expand symbol |
| tables for file names matching REGEXP. |
| |
| `maint cplus first_component NAME' |
| Print the first C++ class/namespace component of NAME. |
| |
| `maint cplus namespace' |
| Print the list of possible C++ namespaces. |
| |
| `maint demangle NAME' |
| Demangle a C++ or Objective-C mangled NAME. |
| |
| `maint deprecate COMMAND [REPLACEMENT]' |
| `maint undeprecate COMMAND' |
| Deprecate or undeprecate the named COMMAND. Deprecated commands |
| cause GDB to issue a warning when you use them. The optional |
| argument REPLACEMENT says which newer command should be used in |
| favor of the deprecated one; if it is given, GDB will mention the |
| replacement as part of the warning. |
| |
| `maint dump-me' |
| Cause a fatal signal in the debugger and force it to dump its core. |
| This is supported only on systems which support aborting a program |
| with the `SIGQUIT' signal. |
| |
| `maint internal-error [MESSAGE-TEXT]' |
| `maint internal-warning [MESSAGE-TEXT]' |
| Cause GDB to call the internal function `internal_error' or |
| `internal_warning' and hence behave as though an internal error or |
| internal warning has been detected. In addition to reporting the |
| internal problem, these functions give the user the opportunity to |
| either quit GDB or create a core file of the current GDB session. |
| |
| These commands take an optional parameter MESSAGE-TEXT that is |
| used as the text of the error or warning message. |
| |
| Here's an example of using `internal-error': |
| |
| (gdb) maint internal-error testing, 1, 2 |
| .../maint.c:121: internal-error: testing, 1, 2 |
| A problem internal to GDB has been detected. Further |
| debugging may prove unreliable. |
| Quit this debugging session? (y or n) n |
| Create a core file? (y or n) n |
| (gdb) |
| |
| `maint set internal-error ACTION [ask|yes|no]' |
| `maint show internal-error ACTION' |
| `maint set internal-warning ACTION [ask|yes|no]' |
| `maint show internal-warning ACTION' |
| When GDB reports an internal problem (error or warning) it gives |
| the user the opportunity to both quit GDB and create a core file |
| of the current GDB session. These commands let you override the |
| default behaviour for each particular ACTION, described in the |
| table below. |
| |
| `quit' |
| You can specify that GDB should always (yes) or never (no) |
| quit. The default is to ask the user what to do. |
| |
| `corefile' |
| You can specify that GDB should always (yes) or never (no) |
| create a core file. The default is to ask the user what to |
| do. |
| |
| `maint packet TEXT' |
| If GDB is talking to an inferior via the serial protocol, then |
| this command sends the string TEXT to the inferior, and displays |
| the response packet. GDB supplies the initial `$' character, the |
| terminating `#' character, and the checksum. |
| |
| `maint print architecture [FILE]' |
| Print the entire architecture configuration. The optional argument |
| FILE names the file where the output goes. |
| |
| `maint print c-tdesc' |
| Print the current target description (*note Target Descriptions::) |
| as a C source file. The created source file can be used in GDB |
| when an XML parser is not available to parse the description. |
| |
| `maint print dummy-frames' |
| Prints the contents of GDB's internal dummy-frame stack. |
| |
| (gdb) b add |
| ... |
| (gdb) print add(2,3) |
| Breakpoint 2, add (a=2, b=3) at ... |
| 58 return (a + b); |
| The program being debugged stopped while in a function called from GDB. |
| ... |
| (gdb) maint print dummy-frames |
| 0x1a57c80: pc=0x01014068 fp=0x0200bddc sp=0x0200bdd6 |
| top=0x0200bdd4 id={stack=0x200bddc,code=0x101405c} |
| call_lo=0x01014000 call_hi=0x01014001 |
| (gdb) |
| |
| Takes an optional file parameter. |
| |
| `maint print registers [FILE]' |
| `maint print raw-registers [FILE]' |
| `maint print cooked-registers [FILE]' |
| `maint print register-groups [FILE]' |
| `maint print remote-registers [FILE]' |
| Print GDB's internal register data structures. |
| |
| The command `maint print raw-registers' includes the contents of |
| the raw register cache; the command `maint print cooked-registers' |
| includes the (cooked) value of all registers, including registers |
| which aren't available on the target nor visible to user; the |
| command `maint print register-groups' includes the groups that |
| each register is a member of; and the command `maint print |
| remote-registers' includes the remote target's register numbers |
| and offsets in the `G' packets. |
| |
| These commands take an optional parameter, a file name to which to |
| write the information. |
| |
| `maint print reggroups [FILE]' |
| Print GDB's internal register group data structures. The optional |
| argument FILE tells to what file to write the information. |
| |
| The register groups info looks like this: |
| |
| (gdb) maint print reggroups |
| Group Type |
| general user |
| float user |
| all user |
| vector user |
| system user |
| save internal |
| restore internal |
| |
| `flushregs' |
| This command forces GDB to flush its internal register cache. |
| |
| `maint print objfiles [REGEXP]' |
| Print a dump of all known object files. If REGEXP is specified, |
| only print object files whose names match REGEXP. For each object |
| file, this command prints its name, address in memory, and all of |
| its psymtabs and symtabs. |
| |
| `maint print section-scripts [REGEXP]' |
| Print a dump of scripts specified in the `.debug_gdb_section' |
| section. If REGEXP is specified, only print scripts loaded by |
| object files matching REGEXP. For each script, this command |
| prints its name as specified in the objfile, and the full path if |
| known. *Note dotdebug_gdb_scripts section::. |
| |
| `maint print statistics' |
| This command prints, for each object file in the program, various |
| data about that object file followed by the byte cache ("bcache") |
| statistics for the object file. The objfile data includes the |
| number of minimal, partial, full, and stabs symbols, the number of |
| types defined by the objfile, the number of as yet unexpanded psym |
| tables, the number of line tables and string tables, and the |
| amount of memory used by the various tables. The bcache |
| statistics include the counts, sizes, and counts of duplicates of |
| all and unique objects, max, average, and median entry size, total |
| memory used and its overhead and savings, and various measures of |
| the hash table size and chain lengths. |
| |
| `maint print target-stack' |
| A "target" is an interface between the debugger and a particular |
| kind of file or process. Targets can be stacked in "strata", so |
| that more than one target can potentially respond to a request. |
| In particular, memory accesses will walk down the stack of targets |
| until they find a target that is interested in handling that |
| particular address. |
| |
| This command prints a short description of each layer that was |
| pushed on the "target stack", starting from the top layer down to |
| the bottom one. |
| |
| `maint print type EXPR' |
| Print the type chain for a type specified by EXPR. The argument |
| can be either a type name or a symbol. If it is a symbol, the |
| type of that symbol is described. The type chain produced by this |
| command is a recursive definition of the data type as stored in |
| GDB's data structures, including its flags and contained types. |
| |
| `maint set dwarf2 always-disassemble' |
| |
| `maint show dwarf2 always-disassemble' |
| Control the behavior of `info address' when using DWARF debugging |
| information. |
| |
| The default is `off', which means that GDB should try to describe |
| a variable's location in an easily readable format. When `on', |
| GDB will instead display the DWARF location expression in an |
| assembly-like format. Note that some locations are too complex |
| for GDB to describe simply; in this case you will always see the |
| disassembly form. |
| |
| Here is an example of the resulting disassembly: |
| |
| (gdb) info addr argc |
| Symbol "argc" is a complex DWARF expression: |
| 1: DW_OP_fbreg 0 |
| |
| For more information on these expressions, see the DWARF standard |
| (http://www.dwarfstd.org/). |
| |
| `maint set dwarf2 max-cache-age' |
| `maint show dwarf2 max-cache-age' |
| Control the DWARF 2 compilation unit cache. |
| |
| In object files with inter-compilation-unit references, such as |
| those produced by the GCC option `-feliminate-dwarf2-dups', the |
| DWARF 2 reader needs to frequently refer to previously read |
| compilation units. This setting controls how long a compilation |
| unit will remain in the cache if it is not referenced. A higher |
| limit means that cached compilation units will be stored in memory |
| longer, and more total memory will be used. Setting it to zero |
| disables caching, which will slow down GDB startup, but reduce |
| memory consumption. |
| |
| `maint set profile' |
| `maint show profile' |
| Control profiling of GDB. |
| |
| Profiling will be disabled until you use the `maint set profile' |
| command to enable it. When you enable profiling, the system will |
| begin collecting timing and execution count data; when you disable |
| profiling or exit GDB, the results will be written to a log file. |
| Remember that if you use profiling, GDB will overwrite the |
| profiling log file (often called `gmon.out'). If you have a |
| record of important profiling data in a `gmon.out' file, be sure |
| to move it to a safe location. |
| |
| Configuring with `--enable-profiling' arranges for GDB to be |
| compiled with the `-pg' compiler option. |
| |
| `maint set show-debug-regs' |
| `maint show show-debug-regs' |
| Control whether to show variables that mirror the hardware debug |
| registers. Use `on' to enable, `off' to disable. If enabled, the |
| debug registers values are shown when GDB inserts or removes a |
| hardware breakpoint or watchpoint, and when the inferior triggers |
| a hardware-assisted breakpoint or watchpoint. |
| |
| `maint set show-all-tib' |
| `maint show show-all-tib' |
| Control whether to show all non zero areas within a 1k block |
| starting at thread local base, when using the `info w32 |
| thread-information-block' command. |
| |
| `maint set per-command' |
| `maint show per-command' |
| GDB can display the resources used by each command. This is |
| useful in debugging performance problems. |
| |
| `maint set per-command space [on|off]' |
| `maint show per-command space' |
| Enable or disable the printing of the memory used by GDB for |
| each command. If enabled, GDB will display how much memory |
| each command took, following the command's own output. This |
| can also be requested by invoking GDB with the `--statistics' |
| command-line switch (*note Mode Options::). |
| |
| `maint set per-command time [on|off]' |
| `maint show per-command time' |
| Enable or disable the printing of the execution time of GDB |
| for each command. If enabled, GDB will display how much time |
| it took to execute each command, following the command's own |
| output. Both CPU time and wallclock time are printed. |
| Printing both is useful when trying to determine whether the |
| cost is CPU or, e.g., disk/network latency. Note that the |
| CPU time printed is for GDB only, it does not include the |
| execution time of the inferior because there's no mechanism |
| currently to compute how much time was spent by GDB and how |
| much time was spent by the program been debugged. This can |
| also be requested by invoking GDB with the `--statistics' |
| command-line switch (*note Mode Options::). |
| |
| `maint set per-command symtab [on|off]' |
| `maint show per-command symtab' |
| Enable or disable the printing of basic symbol table |
| statistics for each command. If enabled, GDB will display |
| the following information: |
| |
| a. number of symbol tables |
| |
| b. number of primary symbol tables |
| |
| c. number of blocks in the blockvector |
| |
| `maint space VALUE' |
| An alias for `maint set per-command space'. A non-zero value |
| enables it, zero disables it. |
| |
| `maint time VALUE' |
| An alias for `maint set per-command time'. A non-zero value |
| enables it, zero disables it. |
| |
| `maint translate-address [SECTION] ADDR' |
| Find the symbol stored at the location specified by the address |
| ADDR and an optional section name SECTION. If found, GDB prints |
| the name of the closest symbol and an offset from the symbol's |
| location to the specified address. This is similar to the `info |
| address' command (*note Symbols::), except that this command also |
| allows to find symbols in other sections. |
| |
| If section was not specified, the section in which the symbol was |
| found is also printed. For dynamically linked executables, the |
| name of executable or shared library containing the symbol is |
| printed as well. |
| |
| |
| The following command is useful for non-interactive invocations of |
| GDB, such as in the test suite. |
| |
| `set watchdog NSEC' |
| Set the maximum number of seconds GDB will wait for the target |
| operation to finish. If this time expires, GDB reports and error |
| and the command is aborted. |
| |
| `show watchdog' |
| Show the current setting of the target wait timeout. |
| |
| |
| File: gdb.info, Node: Remote Protocol, Next: Agent Expressions, Prev: Maintenance Commands, Up: Top |
| |
| Appendix E GDB Remote Serial Protocol |
| ************************************* |
| |
| * Menu: |
| |
| * Overview:: |
| * Packets:: |
| * Stop Reply Packets:: |
| * General Query Packets:: |
| * Architecture-Specific Protocol Details:: |
| * Tracepoint Packets:: |
| * Host I/O Packets:: |
| * Interrupts:: |
| * Notification Packets:: |
| * Remote Non-Stop:: |
| * Packet Acknowledgment:: |
| * Examples:: |
| * File-I/O Remote Protocol Extension:: |
| * Library List Format:: |
| * Library List Format for SVR4 Targets:: |
| * Memory Map Format:: |
| * Thread List Format:: |
| * Traceframe Info Format:: |
| * Branch Trace Format:: |
| |
| |
| File: gdb.info, Node: Overview, Next: Packets, Up: Remote Protocol |
| |
| E.1 Overview |
| ============ |
| |
| There may be occasions when you need to know something about the |
| protocol--for example, if there is only one serial port to your target |
| machine, you might want your program to do something special if it |
| recognizes a packet meant for GDB. |
| |
| In the examples below, `->' and `<-' are used to indicate |
| transmitted and received data, respectively. |
| |
| All GDB commands and responses (other than acknowledgments and |
| notifications, see *note Notification Packets::) are sent as a PACKET. |
| A PACKET is introduced with the character `$', the actual PACKET-DATA, |
| and the terminating character `#' followed by a two-digit CHECKSUM: |
| |
| `$'PACKET-DATA`#'CHECKSUM |
| The two-digit CHECKSUM is computed as the modulo 256 sum of all |
| characters between the leading `$' and the trailing `#' (an eight bit |
| unsigned checksum). |
| |
| Implementors should note that prior to GDB 5.0 the protocol |
| specification also included an optional two-digit SEQUENCE-ID: |
| |
| `$'SEQUENCE-ID`:'PACKET-DATA`#'CHECKSUM |
| |
| That SEQUENCE-ID was appended to the acknowledgment. GDB has never |
| output SEQUENCE-IDs. Stubs that handle packets added since GDB 5.0 |
| must not accept SEQUENCE-ID. |
| |
| When either the host or the target machine receives a packet, the |
| first response expected is an acknowledgment: either `+' (to indicate |
| the package was received correctly) or `-' (to request retransmission): |
| |
| -> `$'PACKET-DATA`#'CHECKSUM |
| <- `+' |
| The `+'/`-' acknowledgments can be disabled once a connection is |
| established. *Note Packet Acknowledgment::, for details. |
| |
| The host (GDB) sends COMMANDs, and the target (the debugging stub |
| incorporated in your program) sends a RESPONSE. In the case of step |
| and continue COMMANDs, the response is only sent when the operation has |
| completed, and the target has again stopped all threads in all attached |
| processes. This is the default all-stop mode behavior, but the remote |
| protocol also supports GDB's non-stop execution mode; see *note Remote |
| Non-Stop::, for details. |
| |
| PACKET-DATA consists of a sequence of characters with the exception |
| of `#' and `$' (see `X' packet for additional exceptions). |
| |
| Fields within the packet should be separated using `,' `;' or `:'. |
| Except where otherwise noted all numbers are represented in HEX with |
| leading zeros suppressed. |
| |
| Implementors should note that prior to GDB 5.0, the character `:' |
| could not appear as the third character in a packet (as it would |
| potentially conflict with the SEQUENCE-ID). |
| |
| Binary data in most packets is encoded either as two hexadecimal |
| digits per byte of binary data. This allowed the traditional remote |
| protocol to work over connections which were only seven-bit clean. |
| Some packets designed more recently assume an eight-bit clean |
| connection, and use a more efficient encoding to send and receive |
| binary data. |
| |
| The binary data representation uses `7d' (ASCII `}') as an escape |
| character. Any escaped byte is transmitted as the escape character |
| followed by the original character XORed with `0x20'. For example, the |
| byte `0x7d' would be transmitted as the two bytes `0x7d 0x5d'. The |
| bytes `0x23' (ASCII `#'), `0x24' (ASCII `$'), and `0x7d' (ASCII `}') |
| must always be escaped. Responses sent by the stub must also escape |
| `0x2a' (ASCII `*'), so that it is not interpreted as the start of a |
| run-length encoded sequence (described next). |
| |
| Response DATA can be run-length encoded to save space. Run-length |
| encoding replaces runs of identical characters with one instance of the |
| repeated character, followed by a `*' and a repeat count. The repeat |
| count is itself sent encoded, to avoid binary characters in DATA: a |
| value of N is sent as `N+29'. For a repeat count greater or equal to |
| 3, this produces a printable ASCII character, e.g. a space (ASCII code |
| 32) for a repeat count of 3. (This is because run-length encoding |
| starts to win for counts 3 or more.) Thus, for example, `0* ' is a |
| run-length encoding of "0000": the space character after `*' means |
| repeat the leading `0' `32 - 29 = 3' more times. |
| |
| The printable characters `#' and `$' or with a numeric value greater |
| than 126 must not be used. Runs of six repeats (`#') or seven repeats |
| (`$') can be expanded using a repeat count of only five (`"'). For |
| example, `00000000' can be encoded as `0*"00'. |
| |
| The error response returned for some packets includes a two character |
| error number. That number is not well defined. |
| |
| For any COMMAND not supported by the stub, an empty response |
| (`$#00') should be returned. That way it is possible to extend the |
| protocol. A newer GDB can tell if a packet is supported based on that |
| response. |
| |
| At a minimum, a stub is required to support the `g' and `G' commands |
| for register access, and the `m' and `M' commands for memory access. |
| Stubs that only control single-threaded targets can implement run |
| control with the `c' (continue), and `s' (step) commands. Stubs that |
| support multi-threading targets should support the `vCont' command. |
| All other commands are optional. |
| |
| |
| File: gdb.info, Node: Packets, Next: Stop Reply Packets, Prev: Overview, Up: Remote Protocol |
| |
| E.2 Packets |
| =========== |
| |
| The following table provides a complete list of all currently defined |
| COMMANDs and their corresponding response DATA. *Note File-I/O Remote |
| Protocol Extension::, for details about the File I/O extension of the |
| remote protocol. |
| |
| Each packet's description has a template showing the packet's overall |
| syntax, followed by an explanation of the packet's meaning. We include |
| spaces in some of the templates for clarity; these are not part of the |
| packet's syntax. No GDB packet uses spaces to separate its components. |
| For example, a template like `foo BAR BAZ' describes a packet beginning |
| with the three ASCII bytes `foo', followed by a BAR, followed directly |
| by a BAZ. GDB does not transmit a space character between the `foo' |
| and the BAR, or between the BAR and the BAZ. |
| |
| Several packets and replies include a THREAD-ID field to identify a |
| thread. Normally these are positive numbers with a target-specific |
| interpretation, formatted as big-endian hex strings. A THREAD-ID can |
| also be a literal `-1' to indicate all threads, or `0' to pick any |
| thread. |
| |
| In addition, the remote protocol supports a multiprocess feature in |
| which the THREAD-ID syntax is extended to optionally include both |
| process and thread ID fields, as `pPID.TID'. The PID (process) and TID |
| (thread) components each have the format described above: a positive |
| number with target-specific interpretation formatted as a big-endian |
| hex string, literal `-1' to indicate all processes or threads |
| (respectively), or `0' to indicate an arbitrary process or thread. |
| Specifying just a process, as `pPID', is equivalent to `pPID.-1'. It |
| is an error to specify all processes but a specific thread, such as |
| `p-1.TID'. Note that the `p' prefix is _not_ used for those packets |
| and replies explicitly documented to include a process ID, rather than |
| a THREAD-ID. |
| |
| The multiprocess THREAD-ID syntax extensions are only used if both |
| GDB and the stub report support for the `multiprocess' feature using |
| `qSupported'. *Note multiprocess extensions::, for more information. |
| |
| Note that all packet forms beginning with an upper- or lower-case |
| letter, other than those described here, are reserved for future use. |
| |
| Here are the packet descriptions. |
| |
| `!' |
| Enable extended mode. In extended mode, the remote server is made |
| persistent. The `R' packet is used to restart the program being |
| debugged. |
| |
| Reply: |
| `OK' |
| The remote target both supports and has enabled extended mode. |
| |
| `?' |
| Indicate the reason the target halted. The reply is the same as |
| for step and continue. This packet has a special interpretation |
| when the target is in non-stop mode; see *note Remote Non-Stop::. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `A ARGLEN,ARGNUM,ARG,...' |
| Initialized `argv[]' array passed into program. ARGLEN specifies |
| the number of bytes in the hex encoded byte stream ARG. See |
| `gdbserver' for more details. |
| |
| Reply: |
| `OK' |
| The arguments were set. |
| |
| `E NN' |
| An error occurred. |
| |
| `b BAUD' |
| (Don't use this packet; its behavior is not well-defined.) Change |
| the serial line speed to BAUD. |
| |
| JTC: _When does the transport layer state change? When it's |
| received, or after the ACK is transmitted. In either case, there |
| are problems if the command or the acknowledgment packet is |
| dropped._ |
| |
| Stan: _If people really wanted to add something like this, and get |
| it working for the first time, they ought to modify ser-unix.c to |
| send some kind of out-of-band message to a specially-setup stub |
| and have the switch happen "in between" packets, so that from |
| remote protocol's point of view, nothing actually happened._ |
| |
| `B ADDR,MODE' |
| Set (MODE is `S') or clear (MODE is `C') a breakpoint at ADDR. |
| |
| Don't use this packet. Use the `Z' and `z' packets instead (*note |
| insert breakpoint or watchpoint packet::). |
| |
| `bc' |
| Backward continue. Execute the target system in reverse. No |
| parameter. *Note Reverse Execution::, for more information. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `bs' |
| Backward single step. Execute one instruction in reverse. No |
| parameter. *Note Reverse Execution::, for more information. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `c [ADDR]' |
| Continue. ADDR is address to resume. If ADDR is omitted, resume |
| at current address. |
| |
| This packet is deprecated for multi-threading support. *Note |
| vCont packet::. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `C SIG[;ADDR]' |
| Continue with signal SIG (hex signal number). If `;ADDR' is |
| omitted, resume at same address. |
| |
| This packet is deprecated for multi-threading support. *Note |
| vCont packet::. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `d' |
| Toggle debug flag. |
| |
| Don't use this packet; instead, define a general set packet (*note |
| General Query Packets::). |
| |
| `D' |
| `D;PID' |
| The first form of the packet is used to detach GDB from the remote |
| system. It is sent to the remote target before GDB disconnects |
| via the `detach' command. |
| |
| The second form, including a process ID, is used when multiprocess |
| protocol extensions are enabled (*note multiprocess extensions::), |
| to detach only a specific process. The PID is specified as a |
| big-endian hex string. |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E NN' |
| for an error |
| |
| `F RC,EE,CF;XX' |
| A reply from GDB to an `F' packet sent by the target. This is |
| part of the File-I/O protocol extension. *Note File-I/O Remote |
| Protocol Extension::, for the specification. |
| |
| `g' |
| Read general registers. |
| |
| Reply: |
| `XX...' |
| Each byte of register data is described by two hex digits. |
| The bytes with the register are transmitted in target byte |
| order. The size of each register and their position within |
| the `g' packet are determined by the GDB internal gdbarch |
| functions `DEPRECATED_REGISTER_RAW_SIZE' and |
| `gdbarch_register_name'. The specification of several |
| standard `g' packets is specified below. |
| |
| When reading registers from a trace frame (*note Using the |
| Collected Data: Analyze Collected Data.), the stub may also |
| return a string of literal `x''s in place of the register |
| data digits, to indicate that the corresponding register has |
| not been collected, thus its value is unavailable. For |
| example, for an architecture with 4 registers of 4 bytes |
| each, the following reply indicates to GDB that registers 0 |
| and 2 have not been collected, while registers 1 and 3 have |
| been collected, and both have zero value: |
| |
| -> `g' |
| <- `xxxxxxxx00000000xxxxxxxx00000000' |
| |
| `E NN' |
| for an error. |
| |
| `G XX...' |
| Write general registers. *Note read registers packet::, for a |
| description of the XX... data. |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E NN' |
| for an error |
| |
| `H OP THREAD-ID' |
| Set thread for subsequent operations (`m', `M', `g', `G', et.al.). |
| OP depends on the operation to be performed: it should be `c' for |
| step and continue operations (note that this is deprecated, |
| supporting the `vCont' command is a better option), `g' for other |
| operations. The thread designator THREAD-ID has the format and |
| interpretation described in *note thread-id syntax::. |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E NN' |
| for an error |
| |
| `i [ADDR[,NNN]]' |
| Step the remote target by a single clock cycle. If `,NNN' is |
| present, cycle step NNN cycles. If ADDR is present, cycle step |
| starting at that address. |
| |
| `I' |
| Signal, then cycle step. *Note step with signal packet::. *Note |
| cycle step packet::. |
| |
| `k' |
| Kill request. |
| |
| FIXME: _There is no description of how to operate when a specific |
| thread context has been selected (i.e. does 'k' kill only that |
| thread?)_. |
| |
| `m ADDR,LENGTH' |
| Read LENGTH bytes of memory starting at address ADDR. Note that |
| ADDR may not be aligned to any particular boundary. |
| |
| The stub need not use any particular size or alignment when |
| gathering data from memory for the response; even if ADDR is |
| word-aligned and LENGTH is a multiple of the word size, the stub |
| is free to use byte accesses, or not. For this reason, this |
| packet may not be suitable for accessing memory-mapped I/O devices. |
| |
| Reply: |
| `XX...' |
| Memory contents; each byte is transmitted as a two-digit |
| hexadecimal number. The reply may contain fewer bytes than |
| requested if the server was able to read only part of the |
| region of memory. |
| |
| `E NN' |
| NN is errno |
| |
| `M ADDR,LENGTH:XX...' |
| Write LENGTH bytes of memory starting at address ADDR. XX... is |
| the data; each byte is transmitted as a two-digit hexadecimal |
| number. |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E NN' |
| for an error (this includes the case where only part of the |
| data was written). |
| |
| `p N' |
| Read the value of register N; N is in hex. *Note read registers |
| packet::, for a description of how the returned register value is |
| encoded. |
| |
| Reply: |
| `XX...' |
| the register's value |
| |
| `E NN' |
| for an error |
| |
| `' |
| Indicating an unrecognized QUERY. |
| |
| `P N...=R...' |
| Write register N... with value R.... The register number N is in |
| hexadecimal, and R... contains two hex digits for each byte in the |
| register (target byte order). |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E NN' |
| for an error |
| |
| `q NAME PARAMS...' |
| `Q NAME PARAMS...' |
| General query (`q') and set (`Q'). These packets are described |
| fully in *note General Query Packets::. |
| |
| `r' |
| Reset the entire system. |
| |
| Don't use this packet; use the `R' packet instead. |
| |
| `R XX' |
| Restart the program being debugged. XX, while needed, is ignored. |
| This packet is only available in extended mode (*note extended |
| mode::). |
| |
| The `R' packet has no reply. |
| |
| `s [ADDR]' |
| Single step. ADDR is the address at which to resume. If ADDR is |
| omitted, resume at same address. |
| |
| This packet is deprecated for multi-threading support. *Note |
| vCont packet::. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `S SIG[;ADDR]' |
| Step with signal. This is analogous to the `C' packet, but |
| requests a single-step, rather than a normal resumption of |
| execution. |
| |
| This packet is deprecated for multi-threading support. *Note |
| vCont packet::. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `t ADDR:PP,MM' |
| Search backwards starting at address ADDR for a match with pattern |
| PP and mask MM. PP and MM are 4 bytes. ADDR must be at least 3 |
| digits. |
| |
| `T THREAD-ID' |
| Find out if the thread THREAD-ID is alive. *Note thread-id |
| syntax::. |
| |
| Reply: |
| `OK' |
| thread is still alive |
| |
| `E NN' |
| thread is dead |
| |
| `v' |
| Packets starting with `v' are identified by a multi-letter name, |
| up to the first `;' or `?' (or the end of the packet). |
| |
| `vAttach;PID' |
| Attach to a new process with the specified process ID PID. The |
| process ID is a hexadecimal integer identifying the process. In |
| all-stop mode, all threads in the attached process are stopped; in |
| non-stop mode, it may be attached without being stopped if that is |
| supported by the target. |
| |
| This packet is only available in extended mode (*note extended |
| mode::). |
| |
| Reply: |
| `E NN' |
| for an error |
| |
| `Any stop packet' |
| for success in all-stop mode (*note Stop Reply Packets::) |
| |
| `OK' |
| for success in non-stop mode (*note Remote Non-Stop::) |
| |
| `vCont[;ACTION[:THREAD-ID]]...' |
| Resume the inferior, specifying different actions for each thread. |
| If an action is specified with no THREAD-ID, then it is applied to |
| any threads that don't have a specific action specified; if no |
| default action is specified then other threads should remain |
| stopped in all-stop mode and in their current state in non-stop |
| mode. Specifying multiple default actions is an error; specifying |
| no actions is also an error. Thread IDs are specified using the |
| syntax described in *note thread-id syntax::. |
| |
| Currently supported actions are: |
| |
| `c' |
| Continue. |
| |
| `C SIG' |
| Continue with signal SIG. The signal SIG should be two hex |
| digits. |
| |
| `s' |
| Step. |
| |
| `S SIG' |
| Step with signal SIG. The signal SIG should be two hex |
| digits. |
| |
| `t' |
| Stop. |
| |
| `r START,END' |
| Step once, and then keep stepping as long as the thread stops |
| at addresses between START (inclusive) and END (exclusive). |
| The remote stub reports a stop reply when either the thread |
| goes out of the range or is stopped due to an unrelated |
| reason, such as hitting a breakpoint. *Note range stepping::. |
| |
| If the range is empty (START == END), then the action becomes |
| equivalent to the `s' action. In other words, single-step |
| once, and report the stop (even if the stepped instruction |
| jumps to START). |
| |
| (A stop reply may be sent at any point even if the PC is |
| still within the stepping range; for example, it is valid to |
| implement this packet in a degenerate way as a single |
| instruction step operation.) |
| |
| |
| The optional argument ADDR normally associated with the `c', `C', |
| `s', and `S' packets is not supported in `vCont'. |
| |
| The `t' action is only relevant in non-stop mode (*note Remote |
| Non-Stop::) and may be ignored by the stub otherwise. A stop |
| reply should be generated for any affected thread not already |
| stopped. When a thread is stopped by means of a `t' action, the |
| corresponding stop reply should indicate that the thread has |
| stopped with signal `0', regardless of whether the target uses |
| some other signal as an implementation detail. |
| |
| The stub must support `vCont' if it reports support for |
| multiprocess extensions (*note multiprocess extensions::). Note |
| that in this case `vCont' actions can be specified to apply to all |
| threads in a process by using the `pPID.-1' form of the THREAD-ID. |
| |
| Reply: *Note Stop Reply Packets::, for the reply specifications. |
| |
| `vCont?' |
| Request a list of actions supported by the `vCont' packet. |
| |
| Reply: |
| `vCont[;ACTION...]' |
| The `vCont' packet is supported. Each ACTION is a supported |
| command in the `vCont' packet. |
| |
| `' |
| The `vCont' packet is not supported. |
| |
| `vFile:OPERATION:PARAMETER...' |
| Perform a file operation on the target system. For details, see |
| *note Host I/O Packets::. |
| |
| `vFlashErase:ADDR,LENGTH' |
| Direct the stub to erase LENGTH bytes of flash starting at ADDR. |
| The region may enclose any number of flash blocks, but its start |
| and end must fall on block boundaries, as indicated by the flash |
| block size appearing in the memory map (*note Memory Map |
| Format::). GDB groups flash memory programming operations |
| together, and sends a `vFlashDone' request after each group; the |
| stub is allowed to delay erase operation until the `vFlashDone' |
| packet is received. |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E NN' |
| for an error |
| |
| `vFlashWrite:ADDR:XX...' |
| Direct the stub to write data to flash address ADDR. The data is |
| passed in binary form using the same encoding as for the `X' |
| packet (*note Binary Data::). The memory ranges specified by |
| `vFlashWrite' packets preceding a `vFlashDone' packet must not |
| overlap, and must appear in order of increasing addresses |
| (although `vFlashErase' packets for higher addresses may already |
| have been received; the ordering is guaranteed only between |
| `vFlashWrite' packets). If a packet writes to an address that was |
| neither erased by a preceding `vFlashErase' packet nor by some |
| other target-specific method, the results are unpredictable. |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E.memtype' |
| for vFlashWrite addressing non-flash memory |
| |
| `E NN' |
| for an error |
| |
| `vFlashDone' |
| Indicate to the stub that flash programming operation is finished. |
| The stub is permitted to delay or batch the effects of a group of |
| `vFlashErase' and `vFlashWrite' packets until a `vFlashDone' |
| packet is received. The contents of the affected regions of flash |
| memory are unpredictable until the `vFlashDone' request is |
| completed. |
| |
| `vKill;PID' |
| Kill the process with the specified process ID. PID is a |
| hexadecimal integer identifying the process. This packet is used |
| in preference to `k' when multiprocess protocol extensions are |
| supported; see *note multiprocess extensions::. |
| |
| Reply: |
| `E NN' |
| for an error |
| |
| `OK' |
| for success |
| |
| `vRun;FILENAME[;ARGUMENT]...' |
| Run the program FILENAME, passing it each ARGUMENT on its command |
| line. The file and arguments are hex-encoded strings. If |
| FILENAME is an empty string, the stub may use a default program |
| (e.g. the last program run). The program is created in the stopped |
| state. |
| |
| This packet is only available in extended mode (*note extended |
| mode::). |
| |
| Reply: |
| `E NN' |
| for an error |
| |
| `Any stop packet' |
| for success (*note Stop Reply Packets::) |
| |
| `vStopped' |
| *Note Notification Packets::. |
| |
| `X ADDR,LENGTH:XX...' |
| Write data to memory, where the data is transmitted in binary. |
| ADDR is address, LENGTH is number of bytes, `XX...' is binary data |
| (*note Binary Data::). |
| |
| Reply: |
| `OK' |
| for success |
| |
| `E NN' |
| for an error |
| |
| `z TYPE,ADDR,KIND' |
| `Z TYPE,ADDR,KIND' |
| Insert (`Z') or remove (`z') a TYPE breakpoint or watchpoint |
| starting at address ADDRESS of kind KIND. |
| |
| Each breakpoint and watchpoint packet TYPE is documented |
| separately. |
| |
| _Implementation notes: A remote target shall return an empty string |
| for an unrecognized breakpoint or watchpoint packet TYPE. A |
| remote target shall support either both or neither of a given |
| `ZTYPE...' and `zTYPE...' packet pair. To avoid potential |
| problems with duplicate packets, the operations should be |
| implemented in an idempotent way._ |
| |
| `z0,ADDR,KIND' |
| `Z0,ADDR,KIND[;COND_LIST...][;cmds:PERSIST,CMD_LIST...]' |
| Insert (`Z0') or remove (`z0') a memory breakpoint at address ADDR |
| of type KIND. |
| |
| A memory breakpoint is implemented by replacing the instruction at |
| ADDR with a software breakpoint or trap instruction. The KIND is |
| target-specific and typically indicates the size of the breakpoint |
| in bytes that should be inserted. E.g., the ARM and MIPS can |
| insert either a 2 or 4 byte breakpoint. Some architectures have |
| additional meanings for KIND; COND_LIST is an optional list of |
| conditional expressions in bytecode form that should be evaluated |
| on the target's side. These are the conditions that should be |
| taken into consideration when deciding if the breakpoint trigger |
| should be reported back to GDBN. |
| |
| The COND_LIST parameter is comprised of a series of expressions, |
| concatenated without separators. Each expression has the following |
| form: |
| |
| `X LEN,EXPR' |
| LEN is the length of the bytecode expression and EXPR is the |
| actual conditional expression in bytecode form. |
| |
| |
| The optional CMD_LIST parameter introduces commands that may be |
| run on the target, rather than being reported back to GDB. The |
| parameter starts with a numeric flag PERSIST; if the flag is |
| nonzero, then the breakpoint may remain active and the commands |
| continue to be run even when GDB disconnects from the target. |
| Following this flag is a series of expressions concatenated with no |
| separators. Each expression has the following form: |
| |
| `X LEN,EXPR' |
| LEN is the length of the bytecode expression and EXPR is the |
| actual conditional expression in bytecode form. |
| |
| |
| see *note Architecture-Specific Protocol Details::. |
| |
| _Implementation note: It is possible for a target to copy or move |
| code that contains memory breakpoints (e.g., when implementing |
| overlays). The behavior of this packet, in the presence of such a |
| target, is not defined._ |
| |
| Reply: |
| `OK' |
| success |
| |
| `' |
| not supported |
| |
| `E NN' |
| for an error |
| |
| `z1,ADDR,KIND' |
| `Z1,ADDR,KIND[;COND_LIST...]' |
| Insert (`Z1') or remove (`z1') a hardware breakpoint at address |
| ADDR. |
| |
| A hardware breakpoint is implemented using a mechanism that is not |
| dependant on being able to modify the target's memory. KIND and |
| COND_LIST have the same meaning as in `Z0' packets. |
| |
| _Implementation note: A hardware breakpoint is not affected by code |
| movement._ |
| |
| Reply: |
| `OK' |
| success |
| |
| `' |
| not supported |
| |
| `E NN' |
| for an error |
| |
| `z2,ADDR,KIND' |
| `Z2,ADDR,KIND' |
| Insert (`Z2') or remove (`z2') a write watchpoint at ADDR. KIND |
| is interpreted as the number of bytes to watch. |
| |
| Reply: |
| `OK' |
| success |
| |
| `' |
| not supported |
| |
| `E NN' |
| for an error |
| |
| `z3,ADDR,KIND' |
| `Z3,ADDR,KIND' |
| Insert (`Z3') or remove (`z3') a read watchpoint at ADDR. KIND is |
| interpreted as the number of bytes to watch. |
| |
| Reply: |
| `OK' |
| success |
| |
| `' |
| not supported |
| |
| `E NN' |
| for an error |
| |
| `z4,ADDR,KIND' |
| `Z4,ADDR,KIND' |
| Insert (`Z4') or remove (`z4') an access watchpoint at ADDR. KIND |
| is interpreted as the number of bytes to watch. |
| |
| Reply: |
| `OK' |
| success |
| |
| `' |
| not supported |
| |
| `E NN' |
| for an error |
| |
| |
| |
| File: gdb.info, Node: Stop Reply Packets, Next: General Query Packets, Prev: Packets, Up: Remote Protocol |
| |
| E.3 Stop Reply Packets |
| ====================== |
| |
| The `C', `c', `S', `s', `vCont', `vAttach', `vRun', `vStopped', and `?' |
| packets can receive any of the below as a reply. Except for `?' and |
| `vStopped', that reply is only returned when the target halts. In the |
| below the exact meaning of "signal number" is defined by the header |
| `include/gdb/signals.h' in the GDB source code. |
| |
| As in the description of request packets, we include spaces in the |
| reply templates for clarity; these are not part of the reply packet's |
| syntax. No GDB stop reply packet uses spaces to separate its |
| components. |
| |
| `S AA' |
| The program received signal number AA (a two-digit hexadecimal |
| number). This is equivalent to a `T' response with no N:R pairs. |
| |
| `T AA N1:R1;N2:R2;...' |
| The program received signal number AA (a two-digit hexadecimal |
| number). This is equivalent to an `S' response, except that the |
| `N:R' pairs can carry values of important registers and other |
| information directly in the stop reply packet, reducing round-trip |
| latency. Single-step and breakpoint traps are reported this way. |
| Each `N:R' pair is interpreted as follows: |
| |
| * If N is a hexadecimal number, it is a register number, and the |
| corresponding R gives that register's value. R is a series |
| of bytes in target byte order, with each byte given by a |
| two-digit hex number. |
| |
| * If N is `thread', then R is the THREAD-ID of the stopped |
| thread, as specified in *note thread-id syntax::. |
| |
| * If N is `core', then R is the hexadecimal number of the core |
| on which the stop event was detected. |
| |
| * If N is a recognized "stop reason", it describes a more |
| specific event that stopped the target. The currently |
| defined stop reasons are listed below. AA should be `05', |
| the trap signal. At most one stop reason should be present. |
| |
| * Otherwise, GDB should ignore this `N:R' pair and go on to the |
| next; this allows us to extend the protocol in the future. |
| |
| The currently defined stop reasons are: |
| |
| `watch' |
| `rwatch' |
| `awatch' |
| The packet indicates a watchpoint hit, and R is the data |
| address, in hex. |
| |
| `library' |
| The packet indicates that the loaded libraries have changed. |
| GDB should use `qXfer:libraries:read' to fetch a new list of |
| loaded libraries. R is ignored. |
| |
| `replaylog' |
| The packet indicates that the target cannot continue replaying |
| logged execution events, because it has reached the end (or |
| the beginning when executing backward) of the log. The value |
| of R will be either `begin' or `end'. *Note Reverse |
| Execution::, for more information. |
| |
| `W AA' |
| `W AA ; process:PID' |
| The process exited, and AA is the exit status. This is only |
| applicable to certain targets. |
| |
| The second form of the response, including the process ID of the |
| exited process, can be used only when GDB has reported support for |
| multiprocess protocol extensions; see *note multiprocess |
| extensions::. The PID is formatted as a big-endian hex string. |
| |
| `X AA' |
| `X AA ; process:PID' |
| The process terminated with signal AA. |
| |
| The second form of the response, including the process ID of the |
| terminated process, can be used only when GDB has reported support |
| for multiprocess protocol extensions; see *note multiprocess |
| extensions::. The PID is formatted as a big-endian hex string. |
| |
| `O XX...' |
| `XX...' is hex encoding of ASCII data, to be written as the |
| program's console output. This can happen at any time while the |
| program is running and the debugger should continue to wait for |
| `W', `T', etc. This reply is not permitted in non-stop mode. |
| |
| `F CALL-ID,PARAMETER...' |
| CALL-ID is the identifier which says which host system call should |
| be called. This is just the name of the function. Translation |
| into the correct system call is only applicable as it's defined in |
| GDB. *Note File-I/O Remote Protocol Extension::, for a list of |
| implemented system calls. |
| |
| `PARAMETER...' is a list of parameters as defined for this very |
| system call. |
| |
| The target replies with this packet when it expects GDB to call a |
| host system call on behalf of the target. GDB replies with an |
| appropriate `F' packet and keeps up waiting for the next reply |
| packet from the target. The latest `C', `c', `S' or `s' action is |
| expected to be continued. *Note File-I/O Remote Protocol |
| Extension::, for more details. |
| |
| |
| |
| File: gdb.info, Node: General Query Packets, Next: Architecture-Specific Protocol Details, Prev: Stop Reply Packets, Up: Remote Protocol |
| |
| E.4 General Query Packets |
| ========================= |
| |
| Packets starting with `q' are "general query packets"; packets starting |
| with `Q' are "general set packets". General query and set packets are |
| a semi-unified form for retrieving and sending information to and from |
| the stub. |
| |
| The initial letter of a query or set packet is followed by a name |
| indicating what sort of thing the packet applies to. For example, GDB |
| may use a `qSymbol' packet to exchange symbol definitions with the |
| stub. These packet names follow some conventions: |
| |
| * The name must not contain commas, colons or semicolons. |
| |
| * Most GDB query and set packets have a leading upper case letter. |
| |
| * The names of custom vendor packets should use a company prefix, in |
| lower case, followed by a period. For example, packets designed at |
| the Acme Corporation might begin with `qacme.foo' (for querying |
| foos) or `Qacme.bar' (for setting bars). |
| |
| The name of a query or set packet should be separated from any |
| parameters by a `:'; the parameters themselves should be separated by |
| `,' or `;'. Stubs must be careful to match the full packet name, and |
| check for a separator or the end of the packet, in case two packet |
| names share a common prefix. New packets should not begin with `qC', |
| `qP', or `qL'(1). |
| |
| Like the descriptions of the other packets, each description here |
| has a template showing the packet's overall syntax, followed by an |
| explanation of the packet's meaning. We include spaces in some of the |
| templates for clarity; these are not part of the packet's syntax. No |
| GDB packet uses spaces to separate its components. |
| |
| Here are the currently defined query and set packets: |
| |
| `QAgent:1' |
| `QAgent:0' |
| Turn on or off the agent as a helper to perform some debugging |
| operations delegated from GDB (*note Control Agent::). |
| |
| `QAllow:OP:VAL...' |
| Specify which operations GDB expects to request of the target, as |
| a semicolon-separated list of operation name and value pairs. |
| Possible values for OP include `WriteReg', `WriteMem', |
| `InsertBreak', `InsertTrace', `InsertFastTrace', and `Stop'. VAL |
| is either 0, indicating that GDB will not request the operation, |
| or 1, indicating that it may. (The target can then use this to |
| set up its own internals optimally, for instance if the debugger |
| never expects to insert breakpoints, it may not need to install |
| its own trap handler.) |
| |
| `qC' |
| Return the current thread ID. |
| |
| Reply: |
| `QC THREAD-ID' |
| Where THREAD-ID is a thread ID as documented in *note |
| thread-id syntax::. |
| |
| `(anything else)' |
| Any other reply implies the old thread ID. |
| |
| `qCRC:ADDR,LENGTH' |
| Compute the CRC checksum of a block of memory using CRC-32 defined |
| in IEEE 802.3. The CRC is computed byte at a time, taking the most |
| significant bit of each byte first. The initial pattern code |
| `0xffffffff' is used to ensure leading zeros affect the CRC. |
| |
| _Note:_ This is the same CRC used in validating separate debug |
| files (*note Debugging Information in Separate Files: Separate |
| Debug Files.). However the algorithm is slightly different. When |
| validating separate debug files, the CRC is computed taking the |
| _least_ significant bit of each byte first, and the final result |
| is inverted to detect trailing zeros. |
| |
| Reply: |
| `E NN' |
| An error (such as memory fault) |
| |
| `C CRC32' |
| The specified memory region's checksum is CRC32. |
| |
| `QDisableRandomization:VALUE' |
| Some target operating systems will randomize the virtual address |
| space of the inferior process as a security feature, but provide a |
| feature to disable such randomization, e.g. to allow for a more |
| deterministic debugging experience. On such systems, this packet |
| with a VALUE of 1 directs the target to disable address space |
| randomization for processes subsequently started via `vRun' |
| packets, while a packet with a VALUE of 0 tells the target to |
| enable address space randomization. |
| |
| This packet is only available in extended mode (*note extended |
| mode::). |
| |
| Reply: |
| `OK' |
| The request succeeded. |
| |
| `E NN' |
| An error occurred. NN are hex digits. |
| |
| `' |
| An empty reply indicates that `QDisableRandomization' is not |
| supported by the stub. |
| |
| This packet is not probed by default; the remote stub must request |
| it, by supplying an appropriate `qSupported' response (*note |
| qSupported::). This should only be done on targets that actually |
| support disabling address space randomization. |
| |
| `qfThreadInfo' |
| `qsThreadInfo' |
| Obtain a list of all active thread IDs from the target (OS). |
| Since there may be too many active threads to fit into one reply |
| packet, this query works iteratively: it may require more than one |
| query/reply sequence to obtain the entire list of threads. The |
| first query of the sequence will be the `qfThreadInfo' query; |
| subsequent queries in the sequence will be the `qsThreadInfo' |
| query. |
| |
| NOTE: This packet replaces the `qL' query (see below). |
| |
| Reply: |
| `m THREAD-ID' |
| A single thread ID |
| |
| `m THREAD-ID,THREAD-ID...' |
| a comma-separated list of thread IDs |
| |
| `l' |
| (lower case letter `L') denotes end of list. |
| |
| In response to each query, the target will reply with a list of |
| one or more thread IDs, separated by commas. GDB will respond to |
| each reply with a request for more thread ids (using the `qs' form |
| of the query), until the target responds with `l' (lower-case ell, |
| for "last"). Refer to *note thread-id syntax::, for the format of |
| the THREAD-ID fields. |
| |
| `qGetTLSAddr:THREAD-ID,OFFSET,LM' |
| Fetch the address associated with thread local storage specified |
| by THREAD-ID, OFFSET, and LM. |
| |
| THREAD-ID is the thread ID associated with the thread for which to |
| fetch the TLS address. *Note thread-id syntax::. |
| |
| OFFSET is the (big endian, hex encoded) offset associated with the |
| thread local variable. (This offset is obtained from the debug |
| information associated with the variable.) |
| |
| LM is the (big endian, hex encoded) OS/ABI-specific encoding of the |
| load module associated with the thread local storage. For example, |
| a GNU/Linux system will pass the link map address of the shared |
| object associated with the thread local storage under |
| consideration. Other operating environments may choose to |
| represent the load module differently, so the precise meaning of |
| this parameter will vary. |
| |
| Reply: |
| `XX...' |
| Hex encoded (big endian) bytes representing the address of |
| the thread local storage requested. |
| |
| `E NN' |
| An error occurred. NN are hex digits. |
| |
| `' |
| An empty reply indicates that `qGetTLSAddr' is not supported |
| by the stub. |
| |
| `qGetTIBAddr:THREAD-ID' |
| Fetch address of the Windows OS specific Thread Information Block. |
| |
| THREAD-ID is the thread ID associated with the thread. |
| |
| Reply: |
| `XX...' |
| Hex encoded (big endian) bytes representing the linear |
| address of the thread information block. |
| |
| `E NN' |
| An error occured. This means that either the thread was not |
| found, or the address could not be retrieved. |
| |
| `' |
| An empty reply indicates that `qGetTIBAddr' is not supported |
| by the stub. |
| |
| `qL STARTFLAG THREADCOUNT NEXTTHREAD' |
| Obtain thread information from RTOS. Where: STARTFLAG (one hex |
| digit) is one to indicate the first query and zero to indicate a |
| subsequent query; THREADCOUNT (two hex digits) is the maximum |
| number of threads the response packet can contain; and NEXTTHREAD |
| (eight hex digits), for subsequent queries (STARTFLAG is zero), is |
| returned in the response as ARGTHREAD. |
| |
| Don't use this packet; use the `qfThreadInfo' query instead (see |
| above). |
| |
| Reply: |
| `qM COUNT DONE ARGTHREAD THREAD...' |
| Where: COUNT (two hex digits) is the number of threads being |
| returned; DONE (one hex digit) is zero to indicate more |
| threads and one indicates no further threads; ARGTHREADID |
| (eight hex digits) is NEXTTHREAD from the request packet; |
| THREAD... is a sequence of thread IDs from the target. |
| THREADID (eight hex digits). See |
| `remote.c:parse_threadlist_response()'. |
| |
| `qOffsets' |
| Get section offsets that the target used when relocating the |
| downloaded image. |
| |
| Reply: |
| `Text=XXX;Data=YYY[;Bss=ZZZ]' |
| Relocate the `Text' section by XXX from its original address. |
| Relocate the `Data' section by YYY from its original address. |
| If the object file format provides segment information (e.g. |
| ELF `PT_LOAD' program headers), GDB will relocate entire |
| segments by the supplied offsets. |
| |
| _Note: while a `Bss' offset may be included in the response, |
| GDB ignores this and instead applies the `Data' offset to the |
| `Bss' section._ |
| |
| `TextSeg=XXX[;DataSeg=YYY]' |
| Relocate the first segment of the object file, which |
| conventionally contains program code, to a starting address |
| of XXX. If `DataSeg' is specified, relocate the second |
| segment, which conventionally contains modifiable data, to a |
| starting address of YYY. GDB will report an error if the |
| object file does not contain segment information, or does not |
| contain at least as many segments as mentioned in the reply. |
| Extra segments are kept at fixed offsets relative to the last |
| relocated segment. |
| |
| `qP MODE THREAD-ID' |
| Returns information on THREAD-ID. Where: MODE is a hex encoded 32 |
| bit mode; THREAD-ID is a thread ID (*note thread-id syntax::). |
| |
| Don't use this packet; use the `qThreadExtraInfo' query instead |
| (see below). |
| |
| Reply: see `remote.c:remote_unpack_thread_info_response()'. |
| |
| `QNonStop:1' |
| `QNonStop:0' |
| Enter non-stop (`QNonStop:1') or all-stop (`QNonStop:0') mode. |
| *Note Remote Non-Stop::, for more information. |
| |
| Reply: |
| `OK' |
| The request succeeded. |
| |
| `E NN' |
| An error occurred. NN are hex digits. |
| |
| `' |
| An empty reply indicates that `QNonStop' is not supported by |
| the stub. |
| |
| This packet is not probed by default; the remote stub must request |
| it, by supplying an appropriate `qSupported' response (*note |
| qSupported::). Use of this packet is controlled by the `set |
| non-stop' command; *note Non-Stop Mode::. |
| |
| `QPassSignals: SIGNAL [;SIGNAL]...' |
| Each listed SIGNAL should be passed directly to the inferior |
| process. Signals are numbered identically to continue packets and |
| stop replies (*note Stop Reply Packets::). Each SIGNAL list item |
| should be strictly greater than the previous item. These signals |
| do not need to stop the inferior, or be reported to GDB. All |
| other signals should be reported to GDB. Multiple `QPassSignals' |
| packets do not combine; any earlier `QPassSignals' list is |
| completely replaced by the new list. This packet improves |
| performance when using `handle SIGNAL nostop noprint pass'. |
| |
| Reply: |
| `OK' |
| The request succeeded. |
| |
| `E NN' |
| An error occurred. NN are hex digits. |
| |
| `' |
| An empty reply indicates that `QPassSignals' is not supported |
| by the stub. |
| |
| Use of this packet is controlled by the `set remote pass-signals' |
| command (*note set remote pass-signals: Remote Configuration.). |
| This packet is not probed by default; the remote stub must request |
| it, by supplying an appropriate `qSupported' response (*note |
| qSupported::). |
| |
| `QProgramSignals: SIGNAL [;SIGNAL]...' |
| Each listed SIGNAL may be delivered to the inferior process. |
| Others should be silently discarded. |
| |
| In some cases, the remote stub may need to decide whether to |
| deliver a signal to the program or not without GDB involvement. |
| One example of that is while detaching -- the program's threads |
| may have stopped for signals that haven't yet had a chance of |
| being reported to GDB, and so the remote stub can use the signal |
| list specified by this packet to know whether to deliver or ignore |
| those pending signals. |
| |
| This does not influence whether to deliver a signal as requested |
| by a resumption packet (*note vCont packet::). |
| |
| Signals are numbered identically to continue packets and stop |
| replies (*note Stop Reply Packets::). Each SIGNAL list item |
| should be strictly greater than the previous item. Multiple |
| `QProgramSignals' packets do not combine; any earlier |
| `QProgramSignals' list is completely replaced by the new list. |
| |
| Reply: |
| `OK' |
| The request succeeded. |
| |
| `E NN' |
| An error occurred. NN are hex digits. |
| |
| `' |
| An empty reply indicates that `QProgramSignals' is not |
| supported by the stub. |
| |
| Use of this packet is controlled by the `set remote |
| program-signals' command (*note set remote program-signals: Remote |
| Configuration.). This packet is not probed by default; the remote |
| stub must request it, by supplying an appropriate `qSupported' |
| response (*note qSupported::). |
| |
| `qRcmd,COMMAND' |
| COMMAND (hex encoded) is passed to the local interpreter for |
| execution. Invalid commands should be reported using the output |
| string. Before the final result packet, the target may also |
| respond with a number of intermediate `OOUTPUT' console output |
| packets. _Implementors should note that providing access to a |
| stubs's interpreter may have security implications_. |
| |
| Reply: |
| `OK' |
| A command response with no output. |
| |
| `OUTPUT' |
| A command response with the hex encoded output string OUTPUT. |
| |
| `E NN' |
| Indicate a badly formed request. |
| |
| `' |
| An empty reply indicates that `qRcmd' is not recognized. |
| |
| (Note that the `qRcmd' packet's name is separated from the command |
| by a `,', not a `:', contrary to the naming conventions above. |
| Please don't use this packet as a model for new packets.) |
| |
| `qSearch:memory:ADDRESS;LENGTH;SEARCH-PATTERN' |
| Search LENGTH bytes at ADDRESS for SEARCH-PATTERN. ADDRESS and |
| LENGTH are encoded in hex. SEARCH-PATTERN is a sequence of bytes, |
| hex encoded. |
| |
| Reply: |
| `0' |
| The pattern was not found. |
| |
| `1,address' |
| The pattern was found at ADDRESS. |
| |
| `E NN' |
| A badly formed request or an error was encountered while |
| searching memory. |
| |
| `' |
| An empty reply indicates that `qSearch:memory' is not |
| recognized. |
| |
| `QStartNoAckMode' |
| Request that the remote stub disable the normal `+'/`-' protocol |
| acknowledgments (*note Packet Acknowledgment::). |
| |
| Reply: |
| `OK' |
| The stub has switched to no-acknowledgment mode. GDB |
| acknowledges this reponse, but neither the stub nor GDB shall |
| send or expect further `+'/`-' acknowledgments in the current |
| connection. |
| |
| `' |
| An empty reply indicates that the stub does not support |
| no-acknowledgment mode. |
| |
| `qSupported [:GDBFEATURE [;GDBFEATURE]... ]' |
| Tell the remote stub about features supported by GDB, and query |
| the stub for features it supports. This packet allows GDB and the |
| remote stub to take advantage of each others' features. |
| `qSupported' also consolidates multiple feature probes at startup, |
| to improve GDB performance--a single larger packet performs better |
| than multiple smaller probe packets on high-latency links. Some |
| features may enable behavior which must not be on by default, e.g. |
| because it would confuse older clients or stubs. Other features |
| may describe packets which could be automatically probed for, but |
| are not. These features must be reported before GDB will use |
| them. This "default unsupported" behavior is not appropriate for |
| all packets, but it helps to keep the initial connection time |
| under control with new versions of GDB which support increasing |
| numbers of packets. |
| |
| Reply: |
| `STUBFEATURE [;STUBFEATURE]...' |
| The stub supports or does not support each returned |
| STUBFEATURE, depending on the form of each STUBFEATURE (see |
| below for the possible forms). |
| |
| `' |
| An empty reply indicates that `qSupported' is not recognized, |
| or that no features needed to be reported to GDB. |
| |
| The allowed forms for each feature (either a GDBFEATURE in the |
| `qSupported' packet, or a STUBFEATURE in the response) are: |
| |
| `NAME=VALUE' |
| The remote protocol feature NAME is supported, and associated |
| with the specified VALUE. The format of VALUE depends on the |
| feature, but it must not include a semicolon. |
| |
| `NAME+' |
| The remote protocol feature NAME is supported, and does not |
| need an associated value. |
| |
| `NAME-' |
| The remote protocol feature NAME is not supported. |
| |
| `NAME?' |
| The remote protocol feature NAME may be supported, and GDB |
| should auto-detect support in some other way when it is |
| needed. This form will not be used for GDBFEATURE |
| notifications, but may be used for STUBFEATURE responses. |
| |
| Whenever the stub receives a `qSupported' request, the supplied |
| set of GDB features should override any previous request. This |
| allows GDB to put the stub in a known state, even if the stub had |
| previously been communicating with a different version of GDB. |
| |
| The following values of GDBFEATURE (for the packet sent by GDB) |
| are defined: |
| |
| `multiprocess' |
| This feature indicates whether GDB supports multiprocess |
| extensions to the remote protocol. GDB does not use such |
| extensions unless the stub also reports that it supports them |
| by including `multiprocess+' in its `qSupported' reply. |
| *Note multiprocess extensions::, for details. |
| |
| `xmlRegisters' |
| This feature indicates that GDB supports the XML target |
| description. If the stub sees `xmlRegisters=' with target |
| specific strings separated by a comma, it will report register |
| description. |
| |
| `qRelocInsn' |
| This feature indicates whether GDB supports the `qRelocInsn' |
| packet (*note Relocate instruction reply packet: Tracepoint |
| Packets.). |
| |
| Stubs should ignore any unknown values for GDBFEATURE. Any GDB |
| which sends a `qSupported' packet supports receiving packets of |
| unlimited length (earlier versions of GDB may reject overly long |
| responses). Additional values for GDBFEATURE may be defined in |
| the future to let the stub take advantage of new features in GDB, |
| e.g. incompatible improvements in the remote protocol--the |
| `multiprocess' feature is an example of such a feature. The |
| stub's reply should be independent of the GDBFEATURE entries sent |
| by GDB; first GDB describes all the features it supports, and then |
| the stub replies with all the features it supports. |
| |
| Similarly, GDB will silently ignore unrecognized stub feature |
| responses, as long as each response uses one of the standard forms. |
| |
| Some features are flags. A stub which supports a flag feature |
| should respond with a `+' form response. Other features require |
| values, and the stub should respond with an `=' form response. |
| |
| Each feature has a default value, which GDB will use if |
| `qSupported' is not available or if the feature is not mentioned |
| in the `qSupported' response. The default values are fixed; a |
| stub is free to omit any feature responses that match the defaults. |
| |
| Not all features can be probed, but for those which can, the |
| probing mechanism is useful: in some cases, a stub's internal |
| architecture may not allow the protocol layer to know some |
| information about the underlying target in advance. This is |
| especially common in stubs which may be configured for multiple |
| targets. |
| |
| These are the currently defined stub features and their properties: |
| |
| Feature Name Value Default Probe Allowed |
| Required |
| `PacketSize' Yes `-' No |
| `qXfer:auxv:read' No `-' Yes |
| `qXfer:btrace:read' No `-' Yes |
| `qXfer:features:read' No `-' Yes |
| `qXfer:libraries:read' No `-' Yes |
| `qXfer:libraries-svr4:read'No `-' Yes |
| `augmented-libraries-svr4-read'No `-' No |
| `qXfer:memory-map:read' No `-' Yes |
| `qXfer:sdata:read' No `-' Yes |
| `qXfer:spu:read' No `-' Yes |
| `qXfer:spu:write' No `-' Yes |
| `qXfer:siginfo:read' No `-' Yes |
| `qXfer:siginfo:write' No `-' Yes |
| `qXfer:threads:read' No `-' Yes |
| `qXfer:traceframe-info:read'No `-' Yes |
| `qXfer:uib:read' No `-' Yes |
| `qXfer:fdpic:read' No `-' Yes |
| `Qbtrace:off' Yes `-' Yes |
| `Qbtrace:bts' Yes `-' Yes |
| `QNonStop' No `-' Yes |
| `QPassSignals' No `-' Yes |
| `QStartNoAckMode' No `-' Yes |
| `multiprocess' No `-' No |
| `ConditionalBreakpoints'No `-' No |
| `ConditionalTracepoints'No `-' No |
| `ReverseContinue' No `-' No |
| `ReverseStep' No `-' No |
| `TracepointSource' No `-' No |
| `QAgent' No `-' No |
| `QAllow' No `-' No |
| `QDisableRandomization' No `-' No |
| `EnableDisableTracepoints'No `-' No |
| `QTBuffer:size' No `-' No |
| `tracenz' No `-' No |
| `BreakpointCommands' No `-' No |
| |
| These are the currently defined stub features, in more detail: |
| |
| `PacketSize=BYTES' |
| The remote stub can accept packets up to at least BYTES in |
| length. GDB will send packets up to this size for bulk |
| transfers, and will never send larger packets. This is a |
| limit on the data characters in the packet, including the |
| frame and checksum. There is no trailing NUL byte in a |
| remote protocol packet; if the stub stores packets in a |
| NUL-terminated format, it should allow an extra byte in its |
| buffer for the NUL. If this stub feature is not supported, |
| GDB guesses based on the size of the `g' packet response. |
| |
| `qXfer:auxv:read' |
| The remote stub understands the `qXfer:auxv:read' packet |
| (*note qXfer auxiliary vector read::). |
| |
| `qXfer:btrace:read' |
| The remote stub understands the `qXfer:btrace:read' packet |
| (*note qXfer btrace read::). |
| |
| `qXfer:features:read' |
| The remote stub understands the `qXfer:features:read' packet |
| (*note qXfer target description read::). |
| |
| `qXfer:libraries:read' |
| The remote stub understands the `qXfer:libraries:read' packet |
| (*note qXfer library list read::). |
| |
| `qXfer:libraries-svr4:read' |
| The remote stub understands the `qXfer:libraries-svr4:read' |
| packet (*note qXfer svr4 library list read::). |
| |
| `augmented-libraries-svr4-read' |
| The remote stub understands the augmented form of the |
| `qXfer:libraries-svr4:read' packet (*note qXfer svr4 library |
| list read::). |
| |
| `qXfer:memory-map:read' |
| The remote stub understands the `qXfer:memory-map:read' packet |
| (*note qXfer memory map read::). |
| |
| `qXfer:sdata:read' |
| The remote stub understands the `qXfer:sdata:read' packet |
| (*note qXfer sdata read::). |
| |
| `qXfer:spu:read' |
| The remote stub understands the `qXfer:spu:read' packet |
| (*note qXfer spu read::). |
| |
| `qXfer:spu:write' |
| The remote stub understands the `qXfer:spu:write' packet |
| (*note qXfer spu write::). |
| |
| `qXfer:siginfo:read' |
| The remote stub understands the `qXfer:siginfo:read' packet |
| (*note qXfer siginfo read::). |
| |
| `qXfer:siginfo:write' |
| The remote stub understands the `qXfer:siginfo:write' packet |
| (*note qXfer siginfo write::). |
| |
| `qXfer:threads:read' |
| The remote stub understands the `qXfer:threads:read' packet |
| (*note qXfer threads read::). |
| |
| `qXfer:traceframe-info:read' |
| The remote stub understands the `qXfer:traceframe-info:read' |
| packet (*note qXfer traceframe info read::). |
| |
| `qXfer:uib:read' |
| The remote stub understands the `qXfer:uib:read' packet |
| (*note qXfer unwind info block::). |
| |
| `qXfer:fdpic:read' |
| The remote stub understands the `qXfer:fdpic:read' packet |
| (*note qXfer fdpic loadmap read::). |
| |
| `QNonStop' |
| The remote stub understands the `QNonStop' packet (*note |
| QNonStop::). |
| |
| `QPassSignals' |
| The remote stub understands the `QPassSignals' packet (*note |
| QPassSignals::). |
| |
| `QStartNoAckMode' |
| The remote stub understands the `QStartNoAckMode' packet and |
| prefers to operate in no-acknowledgment mode. *Note Packet |
| Acknowledgment::. |
| |
| `multiprocess' |
| The remote stub understands the multiprocess extensions to |
| the remote protocol syntax. The multiprocess extensions |
| affect the syntax of thread IDs in both packets and replies |
| (*note thread-id syntax::), and add process IDs to the `D' |
| packet and `W' and `X' replies. Note that reporting this |
| feature indicates support for the syntactic extensions only, |
| not that the stub necessarily supports debugging of more than |
| one process at a time. The stub must not use multiprocess |
| extensions in packet replies unless GDB has also indicated it |
| supports them in its `qSupported' request. |
| |
| `qXfer:osdata:read' |
| The remote stub understands the `qXfer:osdata:read' packet |
| ((*note qXfer osdata read::). |
| |
| `ConditionalBreakpoints' |
| The target accepts and implements evaluation of conditional |
| expressions defined for breakpoints. The target will only |
| report breakpoint triggers when such conditions are true |
| (*note Break Conditions: Conditions.). |
| |
| `ConditionalTracepoints' |
| The remote stub accepts and implements conditional |
| expressions defined for tracepoints (*note Tracepoint |
| Conditions::). |
| |
| `ReverseContinue' |
| The remote stub accepts and implements the reverse continue |
| packet (*note bc::). |
| |
| `ReverseStep' |
| The remote stub accepts and implements the reverse step packet |
| (*note bs::). |
| |
| `TracepointSource' |
| The remote stub understands the `QTDPsrc' packet that supplies |
| the source form of tracepoint definitions. |
| |
| `QAgent' |
| The remote stub understands the `QAgent' packet. |
| |
| `QAllow' |
| The remote stub understands the `QAllow' packet. |
| |
| `QDisableRandomization' |
| The remote stub understands the `QDisableRandomization' |
| packet. |
| |
| `StaticTracepoint' |
| The remote stub supports static tracepoints. |
| |
| `InstallInTrace' |
| The remote stub supports installing tracepoint in tracing. |
| |
| `EnableDisableTracepoints' |
| The remote stub supports the `QTEnable' (*note QTEnable::) and |
| `QTDisable' (*note QTDisable::) packets that allow tracepoints |
| to be enabled and disabled while a trace experiment is |
| running. |
| |
| `QTBuffer:size' |
| The remote stub supports the `QTBuffer:size' (*note |
| QTBuffer-size::) packet that allows to change the size of the |
| trace buffer. |
| |
| `tracenz' |
| The remote stub supports the `tracenz' bytecode for |
| collecting strings. See *note Bytecode Descriptions:: for |
| details about the bytecode. |
| |
| `BreakpointCommands' |
| The remote stub supports running a breakpoint's command list |
| itself, rather than reporting the hit to GDB. |
| |
| `Qbtrace:off' |
| The remote stub understands the `Qbtrace:off' packet. |
| |
| `Qbtrace:bts' |
| The remote stub understands the `Qbtrace:bts' packet. |
| |
| |
| `qSymbol::' |
| Notify the target that GDB is prepared to serve symbol lookup |
| requests. Accept requests from the target for the values of |
| symbols. |
| |
| Reply: |
| `OK' |
| The target does not need to look up any (more) symbols. |
| |
| `qSymbol:SYM_NAME' |
| The target requests the value of symbol SYM_NAME (hex |
| encoded). GDB may provide the value by using the |
| `qSymbol:SYM_VALUE:SYM_NAME' message, described below. |
| |
| `qSymbol:SYM_VALUE:SYM_NAME' |
| Set the value of SYM_NAME to SYM_VALUE. |
| |
| SYM_NAME (hex encoded) is the name of a symbol whose value the |
| target has previously requested. |
| |
| SYM_VALUE (hex) is the value for symbol SYM_NAME. If GDB cannot |
| supply a value for SYM_NAME, then this field will be empty. |
| |
| Reply: |
| `OK' |
| The target does not need to look up any (more) symbols. |
| |
| `qSymbol:SYM_NAME' |
| The target requests the value of a new symbol SYM_NAME (hex |
| encoded). GDB will continue to supply the values of symbols |
| (if available), until the target ceases to request them. |
| |
| `qTBuffer' |
| `QTBuffer' |
| `QTDisconnected' |
| `QTDP' |
| `QTDPsrc' |
| `QTDV' |
| `qTfP' |
| `qTfV' |
| `QTFrame' |
| `qTMinFTPILen' |
| *Note Tracepoint Packets::. |
| |
| `qThreadExtraInfo,THREAD-ID' |
| Obtain a printable string description of a thread's attributes from |
| the target OS. THREAD-ID is a thread ID; see *note thread-id |
| syntax::. This string may contain anything that the target OS |
| thinks is interesting for GDB to tell the user about the thread. |
| The string is displayed in GDB's `info threads' display. Some |
| examples of possible thread extra info strings are `Runnable', or |
| `Blocked on Mutex'. |
| |
| Reply: |
| `XX...' |
| Where `XX...' is a hex encoding of ASCII data, comprising the |
| printable string containing the extra information about the |
| thread's attributes. |
| |
| (Note that the `qThreadExtraInfo' packet's name is separated from |
| the command by a `,', not a `:', contrary to the naming |
| conventions above. Please don't use this packet as a model for new |
| packets.) |
| |
| `QTNotes' |
| `qTP' |
| `QTSave' |
| `qTsP' |
| `qTsV' |
| `QTStart' |
| `QTStop' |
| `QTEnable' |
| `QTDisable' |
| `QTinit' |
| `QTro' |
| `qTStatus' |
| `qTV' |
| `qTfSTM' |
| `qTsSTM' |
| `qTSTMat' |
| *Note Tracepoint Packets::. |
| |
| `qXfer:OBJECT:read:ANNEX:OFFSET,LENGTH' |
| Read uninterpreted bytes from the target's special data area |
| identified by the keyword OBJECT. Request LENGTH bytes starting |
| at OFFSET bytes into the data. The content and encoding of ANNEX |
| is specific to OBJECT; it can supply additional details about what |
| data to access. |
| |
| Here are the specific requests of this form defined so far. All |
| `qXfer:OBJECT:read:...' requests use the same reply formats, |
| listed below. |
| |
| `qXfer:auxv:read::OFFSET,LENGTH' |
| Access the target's "auxiliary vector". *Note auxiliary |
| vector: OS Information. Note ANNEX must be empty. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:btrace:read:ANNEX:OFFSET,LENGTH' |
| Return a description of the current branch trace. *Note |
| Branch Trace Format::. The annex part of the generic `qXfer' |
| packet may have one of the following values: |
| |
| `all' |
| Returns all available branch trace. |
| |
| `new' |
| Returns all available branch trace if the branch trace |
| changed since the last read request. |
| |
| This packet is not probed by default; the remote stub must |
| request it by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:features:read:ANNEX:OFFSET,LENGTH' |
| Access the "target description". *Note Target |
| Descriptions::. The annex specifies which XML document to |
| access. The main description is always loaded from the |
| `target.xml' annex. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:libraries:read:ANNEX:OFFSET,LENGTH' |
| Access the target's list of loaded libraries. *Note Library |
| List Format::. The annex part of the generic `qXfer' packet |
| must be empty (*note qXfer read::). |
| |
| Targets which maintain a list of libraries in the program's |
| memory do not need to implement this packet; it is designed |
| for platforms where the operating system manages the list of |
| loaded libraries. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:libraries-svr4:read:ANNEX:OFFSET,LENGTH' |
| Access the target's list of loaded libraries when the target |
| is an SVR4 platform. *Note Library List Format for SVR4 |
| Targets::. The annex part of the generic `qXfer' packet must |
| be empty unless the remote stub indicated it supports the |
| augmented form of this packet by supplying an appropriate |
| `qSupported' response (*note qXfer read::, *note |
| qSupported::). |
| |
| This packet is optional for better performance on SVR4 |
| targets. GDB uses memory read packets to read the SVR4 |
| library list otherwise. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| If the remote stub indicates it supports the augmented form |
| of this packet then the annex part of the generic `qXfer' |
| packet may contain a semicolon-separated list of `NAME=VALUE' |
| arguments. The currently supported arguments are: |
| |
| `start=ADDRESS' |
| A hexadecimal number specifying the address of the |
| `struct link_map' to start reading the library list |
| from. If unset or zero then the first `struct link_map' |
| in the library list will be chosen as the starting point. |
| |
| `prev=ADDRESS' |
| A hexadecimal number specifying the address of the |
| `struct link_map' immediately preceding the `struct |
| link_map' specified by the `start' argument. If unset |
| or zero then the remote stub will expect that no `struct |
| link_map' exists prior to the starting point. |
| |
| |
| Arguments that are not understood by the remote stub will be |
| silently ignored. |
| |
| `qXfer:memory-map:read::OFFSET,LENGTH' |
| Access the target's "memory-map". *Note Memory Map Format::. |
| The annex part of the generic `qXfer' packet must be empty |
| (*note qXfer read::). |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:sdata:read::OFFSET,LENGTH' |
| Read contents of the extra collected static tracepoint marker |
| information. The annex part of the generic `qXfer' packet |
| must be empty (*note qXfer read::). *Note Tracepoint Action |
| Lists: Tracepoint Actions. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:siginfo:read::OFFSET,LENGTH' |
| Read contents of the extra signal information on the target |
| system. The annex part of the generic `qXfer' packet must be |
| empty (*note qXfer read::). |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:spu:read:ANNEX:OFFSET,LENGTH' |
| Read contents of an `spufs' file on the target system. The |
| annex specifies which file to read; it must be of the form |
| `ID/NAME', where ID specifies an SPU context ID in the target |
| process, and NAME identifes the `spufs' file in that context |
| to be accessed. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:threads:read::OFFSET,LENGTH' |
| Access the list of threads on target. *Note Thread List |
| Format::. The annex part of the generic `qXfer' packet must |
| be empty (*note qXfer read::). |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:traceframe-info:read::OFFSET,LENGTH' |
| Return a description of the current traceframe's contents. |
| *Note Traceframe Info Format::. The annex part of the generic |
| `qXfer' packet must be empty (*note qXfer read::). |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:uib:read:PC:OFFSET,LENGTH' |
| Return the unwind information block for PC. This packet is |
| used on OpenVMS/ia64 to ask the kernel unwind information. |
| |
| This packet is not probed by default. |
| |
| `qXfer:fdpic:read:ANNEX:OFFSET,LENGTH' |
| Read contents of `loadmap's on the target system. The annex, |
| either `exec' or `interp', specifies which `loadmap', |
| executable `loadmap' or interpreter `loadmap' to read. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:osdata:read::OFFSET,LENGTH' |
| Access the target's "operating system information". *Note |
| Operating System Information::. |
| |
| |
| Reply: |
| `m DATA' |
| Data DATA (*note Binary Data::) has been read from the |
| target. There may be more data at a higher address (although |
| it is permitted to return `m' even for the last valid block |
| of data, as long as at least one byte of data was read). |
| DATA may have fewer bytes than the LENGTH in the request. |
| |
| `l DATA' |
| Data DATA (*note Binary Data::) has been read from the target. |
| There is no more data to be read. DATA may have fewer bytes |
| than the LENGTH in the request. |
| |
| `l' |
| The OFFSET in the request is at the end of the data. There |
| is no more data to be read. |
| |
| `E00' |
| The request was malformed, or ANNEX was invalid. |
| |
| `E NN' |
| The offset was invalid, or there was an error encountered |
| reading the data. NN is a hex-encoded `errno' value. |
| |
| `' |
| An empty reply indicates the OBJECT string was not recognized |
| by the stub, or that the object does not support reading. |
| |
| `qXfer:OBJECT:write:ANNEX:OFFSET:DATA...' |
| Write uninterpreted bytes into the target's special data area |
| identified by the keyword OBJECT, starting at OFFSET bytes into |
| the data. DATA... is the binary-encoded data (*note Binary |
| Data::) to be written. The content and encoding of ANNEX is |
| specific to OBJECT; it can supply additional details about what |
| data to access. |
| |
| Here are the specific requests of this form defined so far. All |
| `qXfer:OBJECT:write:...' requests use the same reply formats, |
| listed below. |
| |
| `qXfer:siginfo:write::OFFSET:DATA...' |
| Write DATA to the extra signal information on the target |
| system. The annex part of the generic `qXfer' packet must be |
| empty (*note qXfer write::). |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| `qXfer:spu:write:ANNEX:OFFSET:DATA...' |
| Write DATA to an `spufs' file on the target system. The |
| annex specifies which file to write; it must be of the form |
| `ID/NAME', where ID specifies an SPU context ID in the target |
| process, and NAME identifes the `spufs' file in that context |
| to be accessed. |
| |
| This packet is not probed by default; the remote stub must |
| request it, by supplying an appropriate `qSupported' response |
| (*note qSupported::). |
| |
| Reply: |
| `NN' |
| NN (hex encoded) is the number of bytes written. This may be |
| fewer bytes than supplied in the request. |
| |
| `E00' |
| The request was malformed, or ANNEX was invalid. |
| |
| `E NN' |
| The offset was invalid, or there was an error encountered |
| writing the data. NN is a hex-encoded `errno' value. |
| |
| `' |
| An empty reply indicates the OBJECT string was not recognized |
| by the stub, or that the object does not support writing. |
| |
| `qXfer:OBJECT:OPERATION:...' |
| Requests of this form may be added in the future. When a stub does |
| not recognize the OBJECT keyword, or its support for OBJECT does |
| not recognize the OPERATION keyword, the stub must respond with an |
| empty packet. |
| |
| `qAttached:PID' |
| Return an indication of whether the remote server attached to an |
| existing process or created a new process. When the multiprocess |
| protocol extensions are supported (*note multiprocess |
| extensions::), PID is an integer in hexadecimal format identifying |
| the target process. Otherwise, GDB will omit the PID field and |
| the query packet will be simplified as `qAttached'. |
| |
| This query is used, for example, to know whether the remote process |
| should be detached or killed when a GDB session is ended with the |
| `quit' command. |
| |
| Reply: |
| `1' |
| The remote server attached to an existing process. |
| |
| `0' |
| The remote server created a new process. |
| |
| `E NN' |
| A badly formed request or an error was encountered. |
| |
| `Qbtrace:bts' |
| Enable branch tracing for the current thread using bts tracing. |
| |
| Reply: |
| `OK' |
| Branch tracing has been enabled. |
| |
| `E.errtext' |
| A badly formed request or an error was encountered. |
| |
| `Qbtrace:off' |
| Disable branch tracing for the current thread. |
| |
| Reply: |
| `OK' |
| Branch tracing has been disabled. |
| |
| `E.errtext' |
| A badly formed request or an error was encountered. |
| |
| |
| ---------- Footnotes ---------- |
| |
| (1) The `qP' and `qL' packets predate these conventions, and have |
| arguments without any terminator for the packet name; we suspect they |
| are in widespread use in places that are difficult to upgrade. The |
| `qC' packet has no arguments, but some existing stubs (e.g. RedBoot) |
| are known to not check for the end of the packet. |
| |
| |
| File: gdb.info, Node: Architecture-Specific Protocol Details, Next: Tracepoint Packets, Prev: General Query Packets, Up: Remote Protocol |
| |
| E.5 Architecture-Specific Protocol Details |
| ========================================== |
| |
| This section describes how the remote protocol is applied to specific |
| target architectures. Also see *note Standard Target Features::, for |
| details of XML target descriptions for each architecture. |
| |
| * Menu: |
| |
| * ARM-Specific Protocol Details:: |
| * MIPS-Specific Protocol Details:: |
| |
| |
| File: gdb.info, Node: ARM-Specific Protocol Details, Next: MIPS-Specific Protocol Details, Up: Architecture-Specific Protocol Details |
| |
| E.5.1 ARM-specific Protocol Details |
| ----------------------------------- |
| |
| * Menu: |
| |
| * ARM Breakpoint Kinds:: |
| |
| |
| File: gdb.info, Node: ARM Breakpoint Kinds, Up: ARM-Specific Protocol Details |
| |
| E.5.1.1 ARM Breakpoint Kinds |
| ............................ |
| |
| These breakpoint kinds are defined for the `Z0' and `Z1' packets. |
| |
| 2 |
| 16-bit Thumb mode breakpoint. |
| |
| 3 |
| 32-bit Thumb mode (Thumb-2) breakpoint. |
| |
| 4 |
| 32-bit ARM mode breakpoint. |
| |
| |
| |
| File: gdb.info, Node: MIPS-Specific Protocol Details, Prev: ARM-Specific Protocol Details, Up: Architecture-Specific Protocol Details |
| |
| E.5.2 MIPS-specific Protocol Details |
| ------------------------------------ |
| |
| * Menu: |
| |
| * MIPS Register packet Format:: |
| * MIPS Breakpoint Kinds:: |
| |
| |
| File: gdb.info, Node: MIPS Register packet Format, Next: MIPS Breakpoint Kinds, Up: MIPS-Specific Protocol Details |
| |
| E.5.2.1 MIPS Register Packet Format |
| ................................... |
| |
| The following `g'/`G' packets have previously been defined. In the |
| below, some thirty-two bit registers are transferred as sixty-four |
| bits. Those registers should be zero/sign extended (which?) to fill |
| the space allocated. Register bytes are transferred in target byte |
| order. The two nibbles within a register byte are transferred |
| most-significant - least-significant. |
| |
| MIPS32 |
| All registers are transferred as thirty-two bit quantities in the |
| order: 32 general-purpose; sr; lo; hi; bad; cause; pc; 32 |
| floating-point registers; fsr; fir; fp. |
| |
| MIPS64 |
| All registers are transferred as sixty-four bit quantities |
| (including thirty-two bit registers such as `sr'). The ordering |
| is the same as `MIPS32'. |
| |
| |
| |
| File: gdb.info, Node: MIPS Breakpoint Kinds, Prev: MIPS Register packet Format, Up: MIPS-Specific Protocol Details |
| |
| E.5.2.2 MIPS Breakpoint Kinds |
| ............................. |
| |
| These breakpoint kinds are defined for the `Z0' and `Z1' packets. |
| |
| 2 |
| 16-bit MIPS16 mode breakpoint. |
| |
| 3 |
| 16-bit microMIPS mode breakpoint. |
| |
| 4 |
| 32-bit standard MIPS mode breakpoint. |
| |
| 5 |
| 32-bit microMIPS mode breakpoint. |
| |
| |
| |
| File: gdb.info, Node: Tracepoint Packets, Next: Host I/O Packets, Prev: Architecture-Specific Protocol Details, Up: Remote Protocol |
| |
| E.6 Tracepoint Packets |
| ====================== |
| |
| Here we describe the packets GDB uses to implement tracepoints (*note |
| Tracepoints::). |
| |
| `QTDP:N:ADDR:ENA:STEP:PASS[:FFLEN][:XLEN,BYTES][-]' |
| Create a new tracepoint, number N, at ADDR. If ENA is `E', then |
| the tracepoint is enabled; if it is `D', then the tracepoint is |
| disabled. STEP is the tracepoint's step count, and PASS is its |
| pass count. If an `F' is present, then the tracepoint is to be a |
| fast tracepoint, and the FLEN is the number of bytes that the |
| target should copy elsewhere to make room for the tracepoint. If |
| an `X' is present, it introduces a tracepoint condition, which |
| consists of a hexadecimal length, followed by a comma and |
| hex-encoded bytes, in a manner similar to action encodings as |
| described below. If the trailing `-' is present, further `QTDP' |
| packets will follow to specify this tracepoint's actions. |
| |
| Replies: |
| `OK' |
| The packet was understood and carried out. |
| |
| `qRelocInsn' |
| *Note Relocate instruction reply packet: Tracepoint Packets. |
| |
| `' |
| The packet was not recognized. |
| |
| `QTDP:-N:ADDR:[S]ACTION...[-]' |
| Define actions to be taken when a tracepoint is hit. N and ADDR |
| must be the same as in the initial `QTDP' packet for this |
| tracepoint. This packet may only be sent immediately after |
| another `QTDP' packet that ended with a `-'. If the trailing `-' |
| is present, further `QTDP' packets will follow, specifying more |
| actions for this tracepoint. |
| |
| In the series of action packets for a given tracepoint, at most one |
| can have an `S' before its first ACTION. If such a packet is |
| sent, it and the following packets define "while-stepping" |
| actions. Any prior packets define ordinary actions -- that is, |
| those taken when the tracepoint is first hit. If no action packet |
| has an `S', then all the packets in the series specify ordinary |
| tracepoint actions. |
| |
| The `ACTION...' portion of the packet is a series of actions, |
| concatenated without separators. Each action has one of the |
| following forms: |
| |
| `R MASK' |
| Collect the registers whose bits are set in MASK. MASK is a |
| hexadecimal number whose I'th bit is set if register number I |
| should be collected. (The least significant bit is numbered |
| zero.) Note that MASK may be any number of digits long; it |
| may not fit in a 32-bit word. |
| |
| `M BASEREG,OFFSET,LEN' |
| Collect LEN bytes of memory starting at the address in |
| register number BASEREG, plus OFFSET. If BASEREG is `-1', |
| then the range has a fixed address: OFFSET is the address of |
| the lowest byte to collect. The BASEREG, OFFSET, and LEN |
| parameters are all unsigned hexadecimal values (the `-1' |
| value for BASEREG is a special case). |
| |
| `X LEN,EXPR' |
| Evaluate EXPR, whose length is LEN, and collect memory as it |
| directs. EXPR is an agent expression, as described in *note |
| Agent Expressions::. Each byte of the expression is encoded |
| as a two-digit hex number in the packet; LEN is the number of |
| bytes in the expression (and thus one-half the number of hex |
| digits in the packet). |
| |
| |
| Any number of actions may be packed together in a single `QTDP' |
| packet, as long as the packet does not exceed the maximum packet |
| length (400 bytes, for many stubs). There may be only one `R' |
| action per tracepoint, and it must precede any `M' or `X' actions. |
| Any registers referred to by `M' and `X' actions must be collected |
| by a preceding `R' action. (The "while-stepping" actions are |
| treated as if they were attached to a separate tracepoint, as far |
| as these restrictions are concerned.) |
| |
| Replies: |
| `OK' |
| The packet was understood and carried out. |
| |
| `qRelocInsn' |
| *Note Relocate instruction reply packet: Tracepoint Packets. |
| |
| `' |
| The packet was not recognized. |
| |
| `QTDPsrc:N:ADDR:TYPE:START:SLEN:BYTES' |
| Specify a source string of tracepoint N at address ADDR. This is |
| useful to get accurate reproduction of the tracepoints originally |
| downloaded at the beginning of the trace run. TYPE is the name of |
| the tracepoint part, such as `cond' for the tracepoint's |
| conditional expression (see below for a list of types), while |
| BYTES is the string, encoded in hexadecimal. |
| |
| START is the offset of the BYTES within the overall source string, |
| while SLEN is the total length of the source string. This is |
| intended for handling source strings that are longer than will fit |
| in a single packet. |
| |
| The available string types are `at' for the location, `cond' for |
| the conditional, and `cmd' for an action command. GDB sends a |
| separate packet for each command in the action list, in the same |
| order in which the commands are stored in the list. |
| |
| The target does not need to do anything with source strings except |
| report them back as part of the replies to the `qTfP'/`qTsP' query |
| packets. |
| |
| Although this packet is optional, and GDB will only send it if the |
| target replies with `TracepointSource' *Note General Query |
| Packets::, it makes both disconnected tracing and trace files much |
| easier to use. Otherwise the user must be careful that the |
| tracepoints in effect while looking at trace frames are identical |
| to the ones in effect during the trace run; even a small |
| discrepancy could cause `tdump' not to work, or a particular trace |
| frame not be found. |
| |
| `QTDV:N:VALUE' |
| Create a new trace state variable, number N, with an initial value |
| of VALUE, which is a 64-bit signed integer. Both N and VALUE are |
| encoded as hexadecimal values. GDB has the option of not using |
| this packet for initial values of zero; the target should simply |
| create the trace state variables as they are mentioned in |
| expressions. |
| |
| `QTFrame:N' |
| Select the N'th tracepoint frame from the buffer, and use the |
| register and memory contents recorded there to answer subsequent |
| request packets from GDB. |
| |
| A successful reply from the stub indicates that the stub has found |
| the requested frame. The response is a series of parts, |
| concatenated without separators, describing the frame we selected. |
| Each part has one of the following forms: |
| |
| `F F' |
| The selected frame is number N in the trace frame buffer; F |
| is a hexadecimal number. If F is `-1', then there was no |
| frame matching the criteria in the request packet. |
| |
| `T T' |
| The selected trace frame records a hit of tracepoint number T; |
| T is a hexadecimal number. |
| |
| |
| `QTFrame:pc:ADDR' |
| Like `QTFrame:N', but select the first tracepoint frame after the |
| currently selected frame whose PC is ADDR; ADDR is a hexadecimal |
| number. |
| |
| `QTFrame:tdp:T' |
| Like `QTFrame:N', but select the first tracepoint frame after the |
| currently selected frame that is a hit of tracepoint T; T is a |
| hexadecimal number. |
| |
| `QTFrame:range:START:END' |
| Like `QTFrame:N', but select the first tracepoint frame after the |
| currently selected frame whose PC is between START (inclusive) and |
| END (inclusive); START and END are hexadecimal numbers. |
| |
| `QTFrame:outside:START:END' |
| Like `QTFrame:range:START:END', but select the first frame |
| _outside_ the given range of addresses (exclusive). |
| |
| `qTMinFTPILen' |
| This packet requests the minimum length of instruction at which a |
| fast tracepoint (*note Set Tracepoints::) may be placed. For |
| instance, on the 32-bit x86 architecture, it is possible to use a |
| 4-byte jump, but it depends on the target system being able to |
| create trampolines in the first 64K of memory, which might or |
| might not be possible for that system. So the reply to this |
| packet will be 4 if it is able to arrange for that. |
| |
| Replies: |
| |
| `0' |
| The minimum instruction length is currently unknown. |
| |
| `LENGTH' |
| The minimum instruction length is LENGTH, where LENGTH is |
| greater or equal to 1. LENGTH is a hexadecimal number. A |
| reply of 1 means that a fast tracepoint may be placed on any |
| instruction regardless of size. |
| |
| `E' |
| An error has occurred. |
| |
| `' |
| An empty reply indicates that the request is not supported by |
| the stub. |
| |
| `QTStart' |
| Begin the tracepoint experiment. Begin collecting data from |
| tracepoint hits in the trace frame buffer. This packet supports |
| the `qRelocInsn' reply (*note Relocate instruction reply packet: |
| Tracepoint Packets.). |
| |
| `QTStop' |
| End the tracepoint experiment. Stop collecting trace frames. |
| |
| `QTEnable:N:ADDR' |
| Enable tracepoint N at address ADDR in a started tracepoint |
| experiment. If the tracepoint was previously disabled, then |
| collection of data from it will resume. |
| |
| `QTDisable:N:ADDR' |
| Disable tracepoint N at address ADDR in a started tracepoint |
| experiment. No more data will be collected from the tracepoint |
| unless `QTEnable:N:ADDR' is subsequently issued. |
| |
| `QTinit' |
| Clear the table of tracepoints, and empty the trace frame buffer. |
| |
| `QTro:START1,END1:START2,END2:...' |
| Establish the given ranges of memory as "transparent". The stub |
| will answer requests for these ranges from memory's current |
| contents, if they were not collected as part of the tracepoint hit. |
| |
| GDB uses this to mark read-only regions of memory, like those |
| containing program code. Since these areas never change, they |
| should still have the same contents they did when the tracepoint |
| was hit, so there's no reason for the stub to refuse to provide |
| their contents. |
| |
| `QTDisconnected:VALUE' |
| Set the choice to what to do with the tracing run when GDB |
| disconnects from the target. A VALUE of 1 directs the target to |
| continue the tracing run, while 0 tells the target to stop tracing |
| if GDB is no longer in the picture. |
| |
| `qTStatus' |
| Ask the stub if there is a trace experiment running right now. |
| |
| The reply has the form: |
| |
| `TRUNNING[;FIELD]...' |
| RUNNING is a single digit `1' if the trace is presently |
| running, or `0' if not. It is followed by semicolon-separated |
| optional fields that an agent may use to report additional |
| status. |
| |
| |
| If the trace is not running, the agent may report any of several |
| explanations as one of the optional fields: |
| |
| `tnotrun:0' |
| No trace has been run yet. |
| |
| `tstop[:TEXT]:0' |
| The trace was stopped by a user-originated stop command. The |
| optional TEXT field is a user-supplied string supplied as |
| part of the stop command (for instance, an explanation of why |
| the trace was stopped manually). It is hex-encoded. |
| |
| `tfull:0' |
| The trace stopped because the trace buffer filled up. |
| |
| `tdisconnected:0' |
| The trace stopped because GDB disconnected from the target. |
| |
| `tpasscount:TPNUM' |
| The trace stopped because tracepoint TPNUM exceeded its pass |
| count. |
| |
| `terror:TEXT:TPNUM' |
| The trace stopped because tracepoint TPNUM had an error. The |
| string TEXT is available to describe the nature of the error |
| (for instance, a divide by zero in the condition expression). |
| TEXT is hex encoded. |
| |
| `tunknown:0' |
| The trace stopped for some other reason. |
| |
| |
| Additional optional fields supply statistical and other |
| information. Although not required, they are extremely useful for |
| users monitoring the progress of a trace run. If a trace has |
| stopped, and these numbers are reported, they must reflect the |
| state of the just-stopped trace. |
| |
| `tframes:N' |
| The number of trace frames in the buffer. |
| |
| `tcreated:N' |
| The total number of trace frames created during the run. This |
| may be larger than the trace frame count, if the buffer is |
| circular. |
| |
| `tsize:N' |
| The total size of the trace buffer, in bytes. |
| |
| `tfree:N' |
| The number of bytes still unused in the buffer. |
| |
| `circular:N' |
| The value of the circular trace buffer flag. `1' means that |
| the trace buffer is circular and old trace frames will be |
| discarded if necessary to make room, `0' means that the trace |
| buffer is linear and may fill up. |
| |
| `disconn:N' |
| The value of the disconnected tracing flag. `1' means that |
| tracing will continue after GDB disconnects, `0' means that |
| the trace run will stop. |
| |
| |
| `qTP:TP:ADDR' |
| Ask the stub for the current state of tracepoint number TP at |
| address ADDR. |
| |
| Replies: |
| `VHITS:USAGE' |
| The tracepoint has been hit HITS times so far during the trace |
| run, and accounts for USAGE in the trace buffer. Note that |
| `while-stepping' steps are not counted as separate hits, but |
| the steps' space consumption is added into the usage number. |
| |
| |
| `qTV:VAR' |
| Ask the stub for the value of the trace state variable number VAR. |
| |
| Replies: |
| `VVALUE' |
| The value of the variable is VALUE. This will be the current |
| value of the variable if the user is examining a running |
| target, or a saved value if the variable was collected in the |
| trace frame that the user is looking at. Note that multiple |
| requests may result in different reply values, such as when |
| requesting values while the program is running. |
| |
| `U' |
| The value of the variable is unknown. This would occur, for |
| example, if the user is examining a trace frame in which the |
| requested variable was not collected. |
| |
| `qTfP' |
| `qTsP' |
| These packets request data about tracepoints that are being used by |
| the target. GDB sends `qTfP' to get the first piece of data, and |
| multiple `qTsP' to get additional pieces. Replies to these |
| packets generally take the form of the `QTDP' packets that define |
| tracepoints. (FIXME add detailed syntax) |
| |
| `qTfV' |
| `qTsV' |
| These packets request data about trace state variables that are on |
| the target. GDB sends `qTfV' to get the first vari of data, and |
| multiple `qTsV' to get additional variables. Replies to these |
| packets follow the syntax of the `QTDV' packets that define trace |
| state variables. |
| |
| `qTfSTM' |
| `qTsSTM' |
| These packets request data about static tracepoint markers that |
| exist in the target program. GDB sends `qTfSTM' to get the first |
| piece of data, and multiple `qTsSTM' to get additional pieces. |
| Replies to these packets take the following form: |
| |
| Reply: |
| `m ADDRESS:ID:EXTRA' |
| A single marker |
| |
| `m ADDRESS:ID:EXTRA,ADDRESS:ID:EXTRA...' |
| a comma-separated list of markers |
| |
| `l' |
| (lower case letter `L') denotes end of list. |
| |
| `E NN' |
| An error occurred. NN are hex digits. |
| |
| `' |
| An empty reply indicates that the request is not supported by |
| the stub. |
| |
| ADDRESS is encoded in hex. ID and EXTRA are strings encoded in |
| hex. |
| |
| In response to each query, the target will reply with a list of |
| one or more markers, separated by commas. GDB will respond to each |
| reply with a request for more markers (using the `qs' form of the |
| query), until the target responds with `l' (lower-case ell, for |
| "last"). |
| |
| `qTSTMat:ADDRESS' |
| This packets requests data about static tracepoint markers in the |
| target program at ADDRESS. Replies to this packet follow the |
| syntax of the `qTfSTM' and `qTsSTM' packets that list static |
| tracepoint markers. |
| |
| `QTSave:FILENAME' |
| This packet directs the target to save trace data to the file name |
| FILENAME in the target's filesystem. FILENAME is encoded as a hex |
| string; the interpretation of the file name (relative vs absolute, |
| wild cards, etc) is up to the target. |
| |
| `qTBuffer:OFFSET,LEN' |
| Return up to LEN bytes of the current contents of trace buffer, |
| starting at OFFSET. The trace buffer is treated as if it were a |
| contiguous collection of traceframes, as per the trace file format. |
| The reply consists as many hex-encoded bytes as the target can |
| deliver in a packet; it is not an error to return fewer than were |
| asked for. A reply consisting of just `l' indicates that no bytes |
| are available. |
| |
| `QTBuffer:circular:VALUE' |
| This packet directs the target to use a circular trace buffer if |
| VALUE is 1, or a linear buffer if the value is 0. |
| |
| `QTBuffer:size:SIZE' |
| This packet directs the target to make the trace buffer be of size |
| SIZE if possible. A value of `-1' tells the target to use |
| whatever size it prefers. |
| |
| `QTNotes:[TYPE:TEXT][;TYPE:TEXT]...' |
| This packet adds optional textual notes to the trace run. |
| Allowable types include `user', `notes', and `tstop', the TEXT |
| fields are arbitrary strings, hex-encoded. |
| |
| |
| E.6.1 Relocate instruction reply packet |
| --------------------------------------- |
| |
| When installing fast tracepoints in memory, the target may need to |
| relocate the instruction currently at the tracepoint address to a |
| different address in memory. For most instructions, a simple copy is |
| enough, but, for example, call instructions that implicitly push the |
| return address on the stack, and relative branches or other PC-relative |
| instructions require offset adjustment, so that the effect of executing |
| the instruction at a different address is the same as if it had |
| executed in the original location. |
| |
| In response to several of the tracepoint packets, the target may also |
| respond with a number of intermediate `qRelocInsn' request packets |
| before the final result packet, to have GDB handle this relocation |
| operation. If a packet supports this mechanism, its documentation will |
| explicitly say so. See for example the above descriptions for the |
| `QTStart' and `QTDP' packets. The format of the request is: |
| |
| `qRelocInsn:FROM;TO' |
| This requests GDB to copy instruction at address FROM to address |
| TO, possibly adjusted so that executing the instruction at TO has |
| the same effect as executing it at FROM. GDB writes the adjusted |
| instruction to target memory starting at TO. |
| |
| Replies: |
| `qRelocInsn:ADJUSTED_SIZE' |
| Informs the stub the relocation is complete. ADJUSTED_SIZE is the |
| length in bytes of resulting relocated instruction sequence. |
| |
| `E NN' |
| A badly formed request was detected, or an error was encountered |
| while relocating the instruction. |
| |
| |
| File: gdb.info, Node: Host I/O Packets, Next: Interrupts, Prev: Tracepoint Packets, Up: Remote Protocol |
| |
| E.7 Host I/O Packets |
| ==================== |
| |
| The "Host I/O" packets allow GDB to perform I/O operations on the far |
| side of a remote link. For example, Host I/O is used to upload and |
| download files to a remote target with its own filesystem. Host I/O |
| uses the same constant values and data structure layout as the |
| target-initiated File-I/O protocol. However, the Host I/O packets are |
| structured differently. The target-initiated protocol relies on target |
| memory to store parameters and buffers. Host I/O requests are |
| initiated by GDB, and the target's memory is not involved. *Note |
| File-I/O Remote Protocol Extension::, for more details on the |
| target-initiated protocol. |
| |
| The Host I/O request packets all encode a single operation along with |
| its arguments. They have this format: |
| |
| `vFile:OPERATION: PARAMETER...' |
| OPERATION is the name of the particular request; the target should |
| compare the entire packet name up to the second colon when checking |
| for a supported operation. The format of PARAMETER depends on the |
| operation. Numbers are always passed in hexadecimal. Negative |
| numbers have an explicit minus sign (i.e. two's complement is not |
| used). Strings (e.g. filenames) are encoded as a series of |
| hexadecimal bytes. The last argument to a system call may be a |
| buffer of escaped binary data (*note Binary Data::). |
| |
| |
| The valid responses to Host I/O packets are: |
| |
| `F RESULT [, ERRNO] [; ATTACHMENT]' |
| RESULT is the integer value returned by this operation, usually |
| non-negative for success and -1 for errors. If an error has |
| occured, ERRNO will be included in the result. ERRNO will have a |
| value defined by the File-I/O protocol (*note Errno Values::). For |
| operations which return data, ATTACHMENT supplies the data as a |
| binary buffer. Binary buffers in response packets are escaped in |
| the normal way (*note Binary Data::). See the individual packet |
| documentation for the interpretation of RESULT and ATTACHMENT. |
| |
| `' |
| An empty response indicates that this operation is not recognized. |
| |
| |
| These are the supported Host I/O operations: |
| |
| `vFile:open: PATHNAME, FLAGS, MODE' |
| Open a file at PATHNAME and return a file descriptor for it, or |
| return -1 if an error occurs. PATHNAME is a string, FLAGS is an |
| integer indicating a mask of open flags (*note Open Flags::), and |
| MODE is an integer indicating a mask of mode bits to use if the |
| file is created (*note mode_t Values::). *Note open::, for |
| details of the open flags and mode values. |
| |
| `vFile:close: FD' |
| Close the open file corresponding to FD and return 0, or -1 if an |
| error occurs. |
| |
| `vFile:pread: FD, COUNT, OFFSET' |
| Read data from the open file corresponding to FD. Up to COUNT |
| bytes will be read from the file, starting at OFFSET relative to |
| the start of the file. The target may read fewer bytes; common |
| reasons include packet size limits and an end-of-file condition. |
| The number of bytes read is returned. Zero should only be |
| returned for a successful read at the end of the file, or if COUNT |
| was zero. |
| |
| The data read should be returned as a binary attachment on success. |
| If zero bytes were read, the response should include an empty |
| binary attachment (i.e. a trailing semicolon). The return value |
| is the number of target bytes read; the binary attachment may be |
| longer if some characters were escaped. |
| |
| `vFile:pwrite: FD, OFFSET, DATA' |
| Write DATA (a binary buffer) to the open file corresponding to FD. |
| Start the write at OFFSET from the start of the file. Unlike many |
| `write' system calls, there is no separate COUNT argument; the |
| length of DATA in the packet is used. `vFile:write' returns the |
| number of bytes written, which may be shorter than the length of |
| DATA, or -1 if an error occurred. |
| |
| `vFile:unlink: PATHNAME' |
| Delete the file at PATHNAME on the target. Return 0, or -1 if an |
| error occurs. PATHNAME is a string. |
| |
| `vFile:readlink: FILENAME' |
| Read value of symbolic link FILENAME on the target. Return the |
| number of bytes read, or -1 if an error occurs. |
| |
| The data read should be returned as a binary attachment on success. |
| If zero bytes were read, the response should include an empty |
| binary attachment (i.e. a trailing semicolon). The return value |
| is the number of target bytes read; the binary attachment may be |
| longer if some characters were escaped. |
| |
| |
| |
| File: gdb.info, Node: Interrupts, Next: Notification Packets, Prev: Host I/O Packets, Up: Remote Protocol |
| |
| E.8 Interrupts |
| ============== |
| |
| When a program on the remote target is running, GDB may attempt to |
| interrupt it by sending a `Ctrl-C', `BREAK' or a `BREAK' followed by |
| `g', control of which is specified via GDB's `interrupt-sequence'. |
| |
| The precise meaning of `BREAK' is defined by the transport mechanism |
| and may, in fact, be undefined. GDB does not currently define a |
| `BREAK' mechanism for any of the network interfaces except for TCP, in |
| which case GDB sends the `telnet' BREAK sequence. |
| |
| `Ctrl-C', on the other hand, is defined and implemented for all |
| transport mechanisms. It is represented by sending the single byte |
| `0x03' without any of the usual packet overhead described in the |
| Overview section (*note Overview::). When a `0x03' byte is transmitted |
| as part of a packet, it is considered to be packet data and does _not_ |
| represent an interrupt. E.g., an `X' packet (*note X packet::), used |
| for binary downloads, may include an unescaped `0x03' as part of its |
| packet. |
| |
| `BREAK' followed by `g' is also known as Magic SysRq g. When Linux |
| kernel receives this sequence from serial port, it stops execution and |
| connects to gdb. |
| |
| Stubs are not required to recognize these interrupt mechanisms and |
| the precise meaning associated with receipt of the interrupt is |
| implementation defined. If the target supports debugging of multiple |
| threads and/or processes, it should attempt to interrupt all |
| currently-executing threads and processes. If the stub is successful |
| at interrupting the running program, it should send one of the stop |
| reply packets (*note Stop Reply Packets::) to GDB as a result of |
| successfully stopping the program in all-stop mode, and a stop reply |
| for each stopped thread in non-stop mode. Interrupts received while the |
| program is stopped are discarded. |
| |
| |
| File: gdb.info, Node: Notification Packets, Next: Remote Non-Stop, Prev: Interrupts, Up: Remote Protocol |
| |
| E.9 Notification Packets |
| ======================== |
| |
| The GDB remote serial protocol includes "notifications", packets that |
| require no acknowledgment. Both the GDB and the stub may send |
| notifications (although the only notifications defined at present are |
| sent by the stub). Notifications carry information without incurring |
| the round-trip latency of an acknowledgment, and so are useful for |
| low-impact communications where occasional packet loss is not a problem. |
| |
| A notification packet has the form `% DATA # CHECKSUM', where DATA |
| is the content of the notification, and CHECKSUM is a checksum of DATA, |
| computed and formatted as for ordinary GDB packets. A notification's |
| DATA never contains `$', `%' or `#' characters. Upon receiving a |
| notification, the recipient sends no `+' or `-' to acknowledge the |
| notification's receipt or to report its corruption. |
| |
| Every notification's DATA begins with a name, which contains no |
| colon characters, followed by a colon character. |
| |
| Recipients should silently ignore corrupted notifications and |
| notifications they do not understand. Recipients should restart |
| timeout periods on receipt of a well-formed notification, whether or |
| not they understand it. |
| |
| Senders should only send the notifications described here when this |
| protocol description specifies that they are permitted. In the future, |
| we may extend the protocol to permit existing notifications in new |
| contexts; this rule helps older senders avoid confusing newer |
| recipients. |
| |
| (Older versions of GDB ignore bytes received until they see the `$' |
| byte that begins an ordinary packet, so new stubs may transmit |
| notifications without fear of confusing older clients. There are no |
| notifications defined for GDB to send at the moment, but we assume that |
| most older stubs would ignore them, as well.) |
| |
| Each notification is comprised of three parts: |
| `NAME:EVENT' |
| The notification packet is sent by the side that initiates the |
| exchange (currently, only the stub does that), with EVENT carrying |
| the specific information about the notification. NAME is the name |
| of the notification. |
| |
| `ACK' |
| The acknowledge sent by the other side, usually GDB, to |
| acknowledge the exchange and request the event. |
| |
| The purpose of an asynchronous notification mechanism is to report to |
| GDB that something interesting happened in the remote stub. |
| |
| The remote stub may send notification NAME:EVENT at any time, but |
| GDB acknowledges the notification when appropriate. The notification |
| event is pending before GDB acknowledges. Only one notification at a |
| time may be pending; if additional events occur before GDB has |
| acknowledged the previous notification, they must be queued by the stub |
| for later synchronous transmission in response to ACK packets from GDB. |
| Because the notification mechanism is unreliable, the stub is permitted |
| to resend a notification if it believes GDB may not have received it. |
| |
| Specifically, notifications may appear when GDB is not otherwise |
| reading input from the stub, or when GDB is expecting to read a normal |
| synchronous response or a `+'/`-' acknowledgment to a packet it has |
| sent. Notification packets are distinct from any other communication |
| from the stub so there is no ambiguity. |
| |
| After receiving a notification, GDB shall acknowledge it by sending |
| a ACK packet as a regular, synchronous request to the stub. Such |
| acknowledgment is not required to happen immediately, as GDB is |
| permitted to send other, unrelated packets to the stub first, which the |
| stub should process normally. |
| |
| Upon receiving a ACK packet, if the stub has other queued events to |
| report to GDB, it shall respond by sending a normal EVENT. GDB shall |
| then send another ACK packet to solicit further responses; again, it is |
| permitted to send other, unrelated packets as well which the stub |
| should process normally. |
| |
| If the stub receives a ACK packet and there are no additional EVENT |
| to report, the stub shall return an `OK' response. At this point, GDB |
| has finished processing a notification and the stub has completed |
| sending any queued events. GDB won't accept any new notifications |
| until the final `OK' is received . If further notification events |
| occur, the stub shall send a new notification, GDB shall accept the |
| notification, and the process shall be repeated. |
| |
| The process of asynchronous notification can be illustrated by the |
| following example: |
| <- `%%Stop:T0505:98e7ffbf;04:4ce6ffbf;08:b1b6e54c;thread:p7526.7526;core:0;' |
| `...' |
| -> `vStopped' |
| <- `T0505:68f37db7;04:40f37db7;08:63850408;thread:p7526.7528;core:0;' |
| -> `vStopped' |
| <- `T0505:68e3fdb6;04:40e3fdb6;08:63850408;thread:p7526.7529;core:0;' |
| -> `vStopped' |
| <- `OK' |
| |
| The following notifications are defined: |
| NotificationAck Event Description |
| Stop vStopped REPLY. The REPLY has the Report an asynchronous |
| form of a stop reply, as stop event in non-stop |
| described in *note Stop mode. |
| Reply Packets::. Refer to |
| *note Remote Non-Stop::, |
| for information on how |
| these notifications are |
| acknowledged by GDB. |
| |
| |
| File: gdb.info, Node: Remote Non-Stop, Next: Packet Acknowledgment, Prev: Notification Packets, Up: Remote Protocol |
| |
| E.10 Remote Protocol Support for Non-Stop Mode |
| ============================================== |
| |
| GDB's remote protocol supports non-stop debugging of multi-threaded |
| programs, as described in *note Non-Stop Mode::. If the stub supports |
| non-stop mode, it should report that to GDB by including `QNonStop+' in |
| its `qSupported' response (*note qSupported::). |
| |
| GDB typically sends a `QNonStop' packet only when establishing a new |
| connection with the stub. Entering non-stop mode does not alter the |
| state of any currently-running threads, but targets must stop all |
| threads in any already-attached processes when entering all-stop mode. |
| GDB uses the `?' packet as necessary to probe the target state after a |
| mode change. |
| |
| In non-stop mode, when an attached process encounters an event that |
| would otherwise be reported with a stop reply, it uses the asynchronous |
| notification mechanism (*note Notification Packets::) to inform GDB. |
| In contrast to all-stop mode, where all threads in all processes are |
| stopped when a stop reply is sent, in non-stop mode only the thread |
| reporting the stop event is stopped. That is, when reporting a `S' or |
| `T' response to indicate completion of a step operation, hitting a |
| breakpoint, or a fault, only the affected thread is stopped; any other |
| still-running threads continue to run. When reporting a `W' or `X' |
| response, all running threads belonging to other attached processes |
| continue to run. |
| |
| In non-stop mode, the target shall respond to the `?' packet as |
| follows. First, any incomplete stop reply notification/`vStopped' |
| sequence in progress is abandoned. The target must begin a new |
| sequence reporting stop events for all stopped threads, whether or not |
| it has previously reported those events to GDB. The first stop reply |
| is sent as a synchronous reply to the `?' packet, and subsequent stop |
| replies are sent as responses to `vStopped' packets using the mechanism |
| described above. The target must not send asynchronous stop reply |
| notifications until the sequence is complete. If all threads are |
| running when the target receives the `?' packet, or if the target is |
| not attached to any process, it shall respond `OK'. |
| |
| |
| File: gdb.info, Node: Packet Acknowledgment, Next: Examples, Prev: Remote Non-Stop, Up: Remote Protocol |
| |
| E.11 Packet Acknowledgment |
| ========================== |
| |
| By default, when either the host or the target machine receives a |
| packet, the first response expected is an acknowledgment: either `+' |
| (to indicate the package was received correctly) or `-' (to request |
| retransmission). This mechanism allows the GDB remote protocol to |
| operate over unreliable transport mechanisms, such as a serial line. |
| |
| In cases where the transport mechanism is itself reliable (such as a |
| pipe or TCP connection), the `+'/`-' acknowledgments are redundant. It |
| may be desirable to disable them in that case to reduce communication |
| overhead, or for other reasons. This can be accomplished by means of |
| the `QStartNoAckMode' packet; *note QStartNoAckMode::. |
| |
| When in no-acknowledgment mode, neither the stub nor GDB shall send |
| or expect `+'/`-' protocol acknowledgments. The packet and response |
| format still includes the normal checksum, as described in *note |
| Overview::, but the checksum may be ignored by the receiver. |
| |
| If the stub supports `QStartNoAckMode' and prefers to operate in |
| no-acknowledgment mode, it should report that to GDB by including |
| `QStartNoAckMode+' in its response to `qSupported'; *note qSupported::. |
| If GDB also supports `QStartNoAckMode' and it has not been disabled via |
| the `set remote noack-packet off' command (*note Remote |
| Configuration::), GDB may then send a `QStartNoAckMode' packet to the |
| stub. Only then may the stub actually turn off packet acknowledgments. |
| GDB sends a final `+' acknowledgment of the stub's `OK' response, which |
| can be safely ignored by the stub. |
| |
| Note that `set remote noack-packet' command only affects negotiation |
| between GDB and the stub when subsequent connections are made; it does |
| not affect the protocol acknowledgment state for any current connection. |
| Since `+'/`-' acknowledgments are enabled by default when a new |
| connection is established, there is also no protocol request to |
| re-enable the acknowledgments for the current connection, once disabled. |
| |
| |
| File: gdb.info, Node: Examples, Next: File-I/O Remote Protocol Extension, Prev: Packet Acknowledgment, Up: Remote Protocol |
| |
| E.12 Examples |
| ============= |
| |
| Example sequence of a target being re-started. Notice how the restart |
| does not get any direct output: |
| |
| -> `R00' |
| <- `+' |
| _target restarts_ |
| -> `?' |
| <- `+' |
| <- `T001:1234123412341234' |
| -> `+' |
| |
| Example sequence of a target being stepped by a single instruction: |
| |
| -> `G1445...' |
| <- `+' |
| -> `s' |
| <- `+' |
| _time passes_ |
| <- `T001:1234123412341234' |
| -> `+' |
| -> `g' |
| <- `+' |
| <- `1455...' |
| -> `+' |
| |
| |
| File: gdb.info, Node: File-I/O Remote Protocol Extension, Next: Library List Format, Prev: Examples, Up: Remote Protocol |
| |
| E.13 File-I/O Remote Protocol Extension |
| ======================================= |
| |
| * Menu: |
| |
| * File-I/O Overview:: |
| * Protocol Basics:: |
| * The F Request Packet:: |
| * The F Reply Packet:: |
| * The Ctrl-C Message:: |
| * Console I/O:: |
| * List of Supported Calls:: |
| * Protocol-specific Representation of Datatypes:: |
| * Constants:: |
| * File-I/O Examples:: |
| |
| |
| File: gdb.info, Node: File-I/O Overview, Next: Protocol Basics, Up: File-I/O Remote Protocol Extension |
| |
| E.13.1 File-I/O Overview |
| ------------------------ |
| |
| The "File I/O remote protocol extension" (short: File-I/O) allows the |
| target to use the host's file system and console I/O to perform various |
| system calls. System calls on the target system are translated into a |
| remote protocol packet to the host system, which then performs the |
| needed actions and returns a response packet to the target system. |
| This simulates file system operations even on targets that lack file |
| systems. |
| |
| The protocol is defined to be independent of both the host and |
| target systems. It uses its own internal representation of datatypes |
| and values. Both GDB and the target's GDB stub are responsible for |
| translating the system-dependent value representations into the internal |
| protocol representations when data is transmitted. |
| |
| The communication is synchronous. A system call is possible only |
| when GDB is waiting for a response from the `C', `c', `S' or `s' |
| packets. While GDB handles the request for a system call, the target |
| is stopped to allow deterministic access to the target's memory. |
| Therefore File-I/O is not interruptible by target signals. On the |
| other hand, it is possible to interrupt File-I/O by a user interrupt |
| (`Ctrl-C') within GDB. |
| |
| The target's request to perform a host system call does not finish |
| the latest `C', `c', `S' or `s' action. That means, after finishing |
| the system call, the target returns to continuing the previous activity |
| (continue, step). No additional continue or step request from GDB is |
| required. |
| |
| (gdb) continue |
| <- target requests 'system call X' |
| target is stopped, GDB executes system call |
| -> GDB returns result |
| ... target continues, GDB returns to wait for the target |
| <- target hits breakpoint and sends a Txx packet |
| |
| The protocol only supports I/O on the console and to regular files on |
| the host file system. Character or block special devices, pipes, named |
| pipes, sockets or any other communication method on the host system are |
| not supported by this protocol. |
| |
| File I/O is not supported in non-stop mode. |
| |
| |
| File: gdb.info, Node: Protocol Basics, Next: The F Request Packet, Prev: File-I/O Overview, Up: File-I/O Remote Protocol Extension |
| |
| E.13.2 Protocol Basics |
| ---------------------- |
| |
| The File-I/O protocol uses the `F' packet as the request as well as |
| reply packet. Since a File-I/O system call can only occur when GDB is |
| waiting for a response from the continuing or stepping target, the |
| File-I/O request is a reply that GDB has to expect as a result of a |
| previous `C', `c', `S' or `s' packet. This `F' packet contains all |
| information needed to allow GDB to call the appropriate host system |
| call: |
| |
| * A unique identifier for the requested system call. |
| |
| * All parameters to the system call. Pointers are given as addresses |
| in the target memory address space. Pointers to strings are given |
| as pointer/length pair. Numerical values are given as they are. |
| Numerical control flags are given in a protocol-specific |
| representation. |
| |
| |
| At this point, GDB has to perform the following actions. |
| |
| * If the parameters include pointer values to data needed as input |
| to a system call, GDB requests this data from the target with a |
| standard `m' packet request. This additional communication has to |
| be expected by the target implementation and is handled as any |
| other `m' packet. |
| |
| * GDB translates all value from protocol representation to host |
| representation as needed. Datatypes are coerced into the host |
| types. |
| |
| * GDB calls the system call. |
| |
| * It then coerces datatypes back to protocol representation. |
| |
| * If the system call is expected to return data in buffer space |
| specified by pointer parameters to the call, the data is |
| transmitted to the target using a `M' or `X' packet. This packet |
| has to be expected by the target implementation and is handled as |
| any other `M' or `X' packet. |
| |
| |
| Eventually GDB replies with another `F' packet which contains all |
| necessary information for the target to continue. This at least |
| contains |
| |
| * Return value. |
| |
| * `errno', if has been changed by the system call. |
| |
| * "Ctrl-C" flag. |
| |
| |
| After having done the needed type and value coercion, the target |
| continues the latest continue or step action. |
| |
| |
| File: gdb.info, Node: The F Request Packet, Next: The F Reply Packet, Prev: Protocol Basics, Up: File-I/O Remote Protocol Extension |
| |
| E.13.3 The `F' Request Packet |
| ----------------------------- |
| |
| The `F' request packet has the following format: |
| |
| `FCALL-ID,PARAMETER...' |
| CALL-ID is the identifier to indicate the host system call to be |
| called. This is just the name of the function. |
| |
| PARAMETER... are the parameters to the system call. Parameters |
| are hexadecimal integer values, either the actual values in case |
| of scalar datatypes, pointers to target buffer space in case of |
| compound datatypes and unspecified memory areas, or pointer/length |
| pairs in case of string parameters. These are appended to the |
| CALL-ID as a comma-delimited list. All values are transmitted in |
| ASCII string representation, pointer/length pairs separated by a |
| slash. |
| |
| |
| |
| File: gdb.info, Node: The F Reply Packet, Next: The Ctrl-C Message, Prev: The F Request Packet, Up: File-I/O Remote Protocol Extension |
| |
| E.13.4 The `F' Reply Packet |
| --------------------------- |
| |
| The `F' reply packet has the following format: |
| |
| `FRETCODE,ERRNO,CTRL-C FLAG;CALL-SPECIFIC ATTACHMENT' |
| RETCODE is the return code of the system call as hexadecimal value. |
| |
| ERRNO is the `errno' set by the call, in protocol-specific |
| representation. This parameter can be omitted if the call was |
| successful. |
| |
| CTRL-C FLAG is only sent if the user requested a break. In this |
| case, ERRNO must be sent as well, even if the call was successful. |
| The CTRL-C FLAG itself consists of the character `C': |
| |
| F0,0,C |
| |
| or, if the call was interrupted before the host call has been |
| performed: |
| |
| F-1,4,C |
| |
| assuming 4 is the protocol-specific representation of `EINTR'. |
| |
| |
| |
| File: gdb.info, Node: The Ctrl-C Message, Next: Console I/O, Prev: The F Reply Packet, Up: File-I/O Remote Protocol Extension |
| |
| E.13.5 The `Ctrl-C' Message |
| --------------------------- |
| |
| If the `Ctrl-C' flag is set in the GDB reply packet (*note The F Reply |
| Packet::), the target should behave as if it had gotten a break |
| message. The meaning for the target is "system call interrupted by |
| `SIGINT'". Consequentially, the target should actually stop (as with a |
| break message) and return to GDB with a `T02' packet. |
| |
| It's important for the target to know in which state the system call |
| was interrupted. There are two possible cases: |
| |
| * The system call hasn't been performed on the host yet. |
| |
| * The system call on the host has been finished. |
| |
| |
| These two states can be distinguished by the target by the value of |
| the returned `errno'. If it's the protocol representation of `EINTR', |
| the system call hasn't been performed. This is equivalent to the |
| `EINTR' handling on POSIX systems. In any other case, the target may |
| presume that the system call has been finished -- successfully or not |
| -- and should behave as if the break message arrived right after the |
| system call. |
| |
| GDB must behave reliably. If the system call has not been called |
| yet, GDB may send the `F' reply immediately, setting `EINTR' as `errno' |
| in the packet. If the system call on the host has been finished before |
| the user requests a break, the full action must be finished by GDB. |
| This requires sending `M' or `X' packets as necessary. The `F' packet |
| may only be sent when either nothing has happened or the full action |
| has been completed. |
| |
| |
| File: gdb.info, Node: Console I/O, Next: List of Supported Calls, Prev: The Ctrl-C Message, Up: File-I/O Remote Protocol Extension |
| |
| E.13.6 Console I/O |
| ------------------ |
| |
| By default and if not explicitly closed by the target system, the file |
| descriptors 0, 1 and 2 are connected to the GDB console. Output on the |
| GDB console is handled as any other file output operation (`write(1, |
| ...)' or `write(2, ...)'). Console input is handled by GDB so that |
| after the target read request from file descriptor 0 all following |
| typing is buffered until either one of the following conditions is met: |
| |
| * The user types `Ctrl-c'. The behaviour is as explained above, and |
| the `read' system call is treated as finished. |
| |
| * The user presses <RET>. This is treated as end of input with a |
| trailing newline. |
| |
| * The user types `Ctrl-d'. This is treated as end of input. No |
| trailing character (neither newline nor `Ctrl-D') is appended to |
| the input. |
| |
| |
| If the user has typed more characters than fit in the buffer given to |
| the `read' call, the trailing characters are buffered in GDB until |
| either another `read(0, ...)' is requested by the target, or debugging |
| is stopped at the user's request. |
| |
| |
| File: gdb.info, Node: List of Supported Calls, Next: Protocol-specific Representation of Datatypes, Prev: Console I/O, Up: File-I/O Remote Protocol Extension |
| |
| E.13.7 List of Supported Calls |
| ------------------------------ |
| |
| * Menu: |
| |
| * open:: |
| * close:: |
| * read:: |
| * write:: |
| * lseek:: |
| * rename:: |
| * unlink:: |
| * stat/fstat:: |
| * gettimeofday:: |
| * isatty:: |
| * system:: |
| |
| |
| File: gdb.info, Node: open, Next: close, Up: List of Supported Calls |
| |
| open |
| .... |
| |
| Synopsis: |
| int open(const char *pathname, int flags); |
| int open(const char *pathname, int flags, mode_t mode); |
| |
| Request: |
| `Fopen,PATHPTR/LEN,FLAGS,MODE' |
| |
| FLAGS is the bitwise `OR' of the following values: |
| |
| `O_CREAT' |
| If the file does not exist it will be created. The host |
| rules apply as far as file ownership and time stamps are |
| concerned. |
| |
| `O_EXCL' |
| When used with `O_CREAT', if the file already exists it is an |
| error and open() fails. |
| |
| `O_TRUNC' |
| If the file already exists and the open mode allows writing |
| (`O_RDWR' or `O_WRONLY' is given) it will be truncated to |
| zero length. |
| |
| `O_APPEND' |
| The file is opened in append mode. |
| |
| `O_RDONLY' |
| The file is opened for reading only. |
| |
| `O_WRONLY' |
| The file is opened for writing only. |
| |
| `O_RDWR' |
| The file is opened for reading and writing. |
| |
| Other bits are silently ignored. |
| |
| MODE is the bitwise `OR' of the following values: |
| |
| `S_IRUSR' |
| User has read permission. |
| |
| `S_IWUSR' |
| User has write permission. |
| |
| `S_IRGRP' |
| Group has read permission. |
| |
| `S_IWGRP' |
| Group has write permission. |
| |
| `S_IROTH' |
| Others have read permission. |
| |
| `S_IWOTH' |
| Others have write permission. |
| |
| Other bits are silently ignored. |
| |
| Return value: |
| `open' returns the new file descriptor or -1 if an error occurred. |
| |
| Errors: |
| |
| `EEXIST' |
| PATHNAME already exists and `O_CREAT' and `O_EXCL' were used. |
| |
| `EISDIR' |
| PATHNAME refers to a directory. |
| |
| `EACCES' |
| The requested access is not allowed. |
| |
| `ENAMETOOLONG' |
| PATHNAME was too long. |
| |
| `ENOENT' |
| A directory component in PATHNAME does not exist. |
| |
| `ENODEV' |
| PATHNAME refers to a device, pipe, named pipe or socket. |
| |
| `EROFS' |
| PATHNAME refers to a file on a read-only filesystem and write |
| access was requested. |
| |
| `EFAULT' |
| PATHNAME is an invalid pointer value. |
| |
| `ENOSPC' |
| No space on device to create the file. |
| |
| `EMFILE' |
| The process already has the maximum number of files open. |
| |
| `ENFILE' |
| The limit on the total number of files open on the system has |
| been reached. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: close, Next: read, Prev: open, Up: List of Supported Calls |
| |
| close |
| ..... |
| |
| Synopsis: |
| int close(int fd); |
| |
| Request: |
| `Fclose,FD' |
| |
| Return value: |
| `close' returns zero on success, or -1 if an error occurred. |
| |
| Errors: |
| |
| `EBADF' |
| FD isn't a valid open file descriptor. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: read, Next: write, Prev: close, Up: List of Supported Calls |
| |
| read |
| .... |
| |
| Synopsis: |
| int read(int fd, void *buf, unsigned int count); |
| |
| Request: |
| `Fread,FD,BUFPTR,COUNT' |
| |
| Return value: |
| On success, the number of bytes read is returned. Zero indicates |
| end of file. If count is zero, read returns zero as well. On |
| error, -1 is returned. |
| |
| Errors: |
| |
| `EBADF' |
| FD is not a valid file descriptor or is not open for reading. |
| |
| `EFAULT' |
| BUFPTR is an invalid pointer value. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: write, Next: lseek, Prev: read, Up: List of Supported Calls |
| |
| write |
| ..... |
| |
| Synopsis: |
| int write(int fd, const void *buf, unsigned int count); |
| |
| Request: |
| `Fwrite,FD,BUFPTR,COUNT' |
| |
| Return value: |
| On success, the number of bytes written are returned. Zero |
| indicates nothing was written. On error, -1 is returned. |
| |
| Errors: |
| |
| `EBADF' |
| FD is not a valid file descriptor or is not open for writing. |
| |
| `EFAULT' |
| BUFPTR is an invalid pointer value. |
| |
| `EFBIG' |
| An attempt was made to write a file that exceeds the |
| host-specific maximum file size allowed. |
| |
| `ENOSPC' |
| No space on device to write the data. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: lseek, Next: rename, Prev: write, Up: List of Supported Calls |
| |
| lseek |
| ..... |
| |
| Synopsis: |
| long lseek (int fd, long offset, int flag); |
| |
| Request: |
| `Flseek,FD,OFFSET,FLAG' |
| |
| FLAG is one of: |
| |
| `SEEK_SET' |
| The offset is set to OFFSET bytes. |
| |
| `SEEK_CUR' |
| The offset is set to its current location plus OFFSET bytes. |
| |
| `SEEK_END' |
| The offset is set to the size of the file plus OFFSET bytes. |
| |
| Return value: |
| On success, the resulting unsigned offset in bytes from the |
| beginning of the file is returned. Otherwise, a value of -1 is |
| returned. |
| |
| Errors: |
| |
| `EBADF' |
| FD is not a valid open file descriptor. |
| |
| `ESPIPE' |
| FD is associated with the GDB console. |
| |
| `EINVAL' |
| FLAG is not a proper value. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: rename, Next: unlink, Prev: lseek, Up: List of Supported Calls |
| |
| rename |
| ...... |
| |
| Synopsis: |
| int rename(const char *oldpath, const char *newpath); |
| |
| Request: |
| `Frename,OLDPATHPTR/LEN,NEWPATHPTR/LEN' |
| |
| Return value: |
| On success, zero is returned. On error, -1 is returned. |
| |
| Errors: |
| |
| `EISDIR' |
| NEWPATH is an existing directory, but OLDPATH is not a |
| directory. |
| |
| `EEXIST' |
| NEWPATH is a non-empty directory. |
| |
| `EBUSY' |
| OLDPATH or NEWPATH is a directory that is in use by some |
| process. |
| |
| `EINVAL' |
| An attempt was made to make a directory a subdirectory of |
| itself. |
| |
| `ENOTDIR' |
| A component used as a directory in OLDPATH or new path is |
| not a directory. Or OLDPATH is a directory and NEWPATH |
| exists but is not a directory. |
| |
| `EFAULT' |
| OLDPATHPTR or NEWPATHPTR are invalid pointer values. |
| |
| `EACCES' |
| No access to the file or the path of the file. |
| |
| `ENAMETOOLONG' |
| OLDPATH or NEWPATH was too long. |
| |
| `ENOENT' |
| A directory component in OLDPATH or NEWPATH does not exist. |
| |
| `EROFS' |
| The file is on a read-only filesystem. |
| |
| `ENOSPC' |
| The device containing the file has no room for the new |
| directory entry. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: unlink, Next: stat/fstat, Prev: rename, Up: List of Supported Calls |
| |
| unlink |
| ...... |
| |
| Synopsis: |
| int unlink(const char *pathname); |
| |
| Request: |
| `Funlink,PATHNAMEPTR/LEN' |
| |
| Return value: |
| On success, zero is returned. On error, -1 is returned. |
| |
| Errors: |
| |
| `EACCES' |
| No access to the file or the path of the file. |
| |
| `EPERM' |
| The system does not allow unlinking of directories. |
| |
| `EBUSY' |
| The file PATHNAME cannot be unlinked because it's being used |
| by another process. |
| |
| `EFAULT' |
| PATHNAMEPTR is an invalid pointer value. |
| |
| `ENAMETOOLONG' |
| PATHNAME was too long. |
| |
| `ENOENT' |
| A directory component in PATHNAME does not exist. |
| |
| `ENOTDIR' |
| A component of the path is not a directory. |
| |
| `EROFS' |
| The file is on a read-only filesystem. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: stat/fstat, Next: gettimeofday, Prev: unlink, Up: List of Supported Calls |
| |
| stat/fstat |
| .......... |
| |
| Synopsis: |
| int stat(const char *pathname, struct stat *buf); |
| int fstat(int fd, struct stat *buf); |
| |
| Request: |
| `Fstat,PATHNAMEPTR/LEN,BUFPTR' |
| `Ffstat,FD,BUFPTR' |
| |
| Return value: |
| On success, zero is returned. On error, -1 is returned. |
| |
| Errors: |
| |
| `EBADF' |
| FD is not a valid open file. |
| |
| `ENOENT' |
| A directory component in PATHNAME does not exist or the path |
| is an empty string. |
| |
| `ENOTDIR' |
| A component of the path is not a directory. |
| |
| `EFAULT' |
| PATHNAMEPTR is an invalid pointer value. |
| |
| `EACCES' |
| No access to the file or the path of the file. |
| |
| `ENAMETOOLONG' |
| PATHNAME was too long. |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| |
| File: gdb.info, Node: gettimeofday, Next: isatty, Prev: stat/fstat, Up: List of Supported Calls |
| |
| gettimeofday |
| ............ |
| |
| Synopsis: |
| int gettimeofday(struct timeval *tv, void *tz); |
| |
| Request: |
| `Fgettimeofday,TVPTR,TZPTR' |
| |
| Return value: |
| On success, 0 is returned, -1 otherwise. |
| |
| Errors: |
| |
| `EINVAL' |
| TZ is a non-NULL pointer. |
| |
| `EFAULT' |
| TVPTR and/or TZPTR is an invalid pointer value. |
| |
| |
| |
| File: gdb.info, Node: isatty, Next: system, Prev: gettimeofday, Up: List of Supported Calls |
| |
| isatty |
| ...... |
| |
| Synopsis: |
| int isatty(int fd); |
| |
| Request: |
| `Fisatty,FD' |
| |
| Return value: |
| Returns 1 if FD refers to the GDB console, 0 otherwise. |
| |
| Errors: |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| Note that the `isatty' call is treated as a special case: it returns |
| 1 to the target if the file descriptor is attached to the GDB console, |
| 0 otherwise. Implementing through system calls would require |
| implementing `ioctl' and would be more complex than needed. |
| |
| |
| File: gdb.info, Node: system, Prev: isatty, Up: List of Supported Calls |
| |
| system |
| ...... |
| |
| Synopsis: |
| int system(const char *command); |
| |
| Request: |
| `Fsystem,COMMANDPTR/LEN' |
| |
| Return value: |
| If LEN is zero, the return value indicates whether a shell is |
| available. A zero return value indicates a shell is not available. |
| For non-zero LEN, the value returned is -1 on error and the return |
| status of the command otherwise. Only the exit status of the |
| command is returned, which is extracted from the host's `system' |
| return value by calling `WEXITSTATUS(retval)'. In case `/bin/sh' |
| could not be executed, 127 is returned. |
| |
| Errors: |
| |
| `EINTR' |
| The call was interrupted by the user. |
| |
| |
| GDB takes over the full task of calling the necessary host calls to |
| perform the `system' call. The return value of `system' on the host is |
| simplified before it's returned to the target. Any termination signal |
| information from the child process is discarded, and the return value |
| consists entirely of the exit status of the called command. |
| |
| Due to security concerns, the `system' call is by default refused by |
| GDB. The user has to allow this call explicitly with the `set remote |
| system-call-allowed 1' command. |
| |
| `set remote system-call-allowed' |
| Control whether to allow the `system' calls in the File I/O |
| protocol for the remote target. The default is zero (disabled). |
| |
| `show remote system-call-allowed' |
| Show whether the `system' calls are allowed in the File I/O |
| protocol. |
| |
| |
| File: gdb.info, Node: Protocol-specific Representation of Datatypes, Next: Constants, Prev: List of Supported Calls, Up: File-I/O Remote Protocol Extension |
| |
| E.13.8 Protocol-specific Representation of Datatypes |
| ---------------------------------------------------- |
| |
| * Menu: |
| |
| * Integral Datatypes:: |
| * Pointer Values:: |
| * Memory Transfer:: |
| * struct stat:: |
| * struct timeval:: |
| |
| |
| File: gdb.info, Node: Integral Datatypes, Next: Pointer Values, Up: Protocol-specific Representation of Datatypes |
| |
| Integral Datatypes |
| .................. |
| |
| The integral datatypes used in the system calls are `int', `unsigned |
| int', `long', `unsigned long', `mode_t', and `time_t'. |
| |
| `int', `unsigned int', `mode_t' and `time_t' are implemented as 32 |
| bit values in this protocol. |
| |
| `long' and `unsigned long' are implemented as 64 bit types. |
| |
| *Note Limits::, for corresponding MIN and MAX values (similar to |
| those in `limits.h') to allow range checking on host and target. |
| |
| `time_t' datatypes are defined as seconds since the Epoch. |
| |
| All integral datatypes transferred as part of a memory read or write |
| of a structured datatype e.g. a `struct stat' have to be given in big |
| endian byte order. |
| |
| |
| File: gdb.info, Node: Pointer Values, Next: Memory Transfer, Prev: Integral Datatypes, Up: Protocol-specific Representation of Datatypes |
| |
| Pointer Values |
| .............. |
| |
| Pointers to target data are transmitted as they are. An exception is |
| made for pointers to buffers for which the length isn't transmitted as |
| part of the function call, namely strings. Strings are transmitted as |
| a pointer/length pair, both as hex values, e.g. |
| |
| `1aaf/12' |
| |
| which is a pointer to data of length 18 bytes at position 0x1aaf. The |
| length is defined as the full string length in bytes, including the |
| trailing null byte. For example, the string `"hello world"' at address |
| 0x123456 is transmitted as |
| |
| `123456/d' |
| |
| |
| File: gdb.info, Node: Memory Transfer, Next: struct stat, Prev: Pointer Values, Up: Protocol-specific Representation of Datatypes |
| |
| Memory Transfer |
| ............... |
| |
| Structured data which is transferred using a memory read or write (for |
| example, a `struct stat') is expected to be in a protocol-specific |
| format with all scalar multibyte datatypes being big endian. |
| Translation to this representation needs to be done both by the target |
| before the `F' packet is sent, and by GDB before it transfers memory to |
| the target. Transferred pointers to structured data should point to |
| the already-coerced data at any time. |
| |
| |
| File: gdb.info, Node: struct stat, Next: struct timeval, Prev: Memory Transfer, Up: Protocol-specific Representation of Datatypes |
| |
| struct stat |
| ........... |
| |
| The buffer of type `struct stat' used by the target and GDB is defined |
| as follows: |
| |
| struct stat { |
| unsigned int st_dev; /* device */ |
| unsigned int st_ino; /* inode */ |
| mode_t st_mode; /* protection */ |
| unsigned int st_nlink; /* number of hard links */ |
| unsigned int st_uid; /* user ID of owner */ |
| unsigned int st_gid; /* group ID of owner */ |
| unsigned int st_rdev; /* device type (if inode device) */ |
| unsigned long st_size; /* total size, in bytes */ |
| unsigned long st_blksize; /* blocksize for filesystem I/O */ |
| unsigned long st_blocks; /* number of blocks allocated */ |
| time_t st_atime; /* time of last access */ |
| time_t st_mtime; /* time of last modification */ |
| time_t st_ctime; /* time of last change */ |
| }; |
| |
| The integral datatypes conform to the definitions given in the |
| appropriate section (see *note Integral Datatypes::, for details) so |
| this structure is of size 64 bytes. |
| |
| The values of several fields have a restricted meaning and/or range |
| of values. |
| |
| `st_dev' |
| A value of 0 represents a file, 1 the console. |
| |
| `st_ino' |
| No valid meaning for the target. Transmitted unchanged. |
| |
| `st_mode' |
| Valid mode bits are described in *note Constants::. Any other |
| bits have currently no meaning for the target. |
| |
| `st_uid' |
| `st_gid' |
| `st_rdev' |
| No valid meaning for the target. Transmitted unchanged. |
| |
| `st_atime' |
| `st_mtime' |
| `st_ctime' |
| These values have a host and file system dependent accuracy. |
| Especially on Windows hosts, the file system may not support exact |
| timing values. |
| |
| The target gets a `struct stat' of the above representation and is |
| responsible for coercing it to the target representation before |
| continuing. |
| |
| Note that due to size differences between the host, target, and |
| protocol representations of `struct stat' members, these members could |
| eventually get truncated on the target. |
| |
| |
| File: gdb.info, Node: struct timeval, Prev: struct stat, Up: Protocol-specific Representation of Datatypes |
| |
| struct timeval |
| .............. |
| |
| The buffer of type `struct timeval' used by the File-I/O protocol is |
| defined as follows: |
| |
| struct timeval { |
| time_t tv_sec; /* second */ |
| long tv_usec; /* microsecond */ |
| }; |
| |
| The integral datatypes conform to the definitions given in the |
| appropriate section (see *note Integral Datatypes::, for details) so |
| this structure is of size 8 bytes. |
| |
| |
| File: gdb.info, Node: Constants, Next: File-I/O Examples, Prev: Protocol-specific Representation of Datatypes, Up: File-I/O Remote Protocol Extension |
| |
| E.13.9 Constants |
| ---------------- |
| |
| The following values are used for the constants inside of the protocol. |
| GDB and target are responsible for translating these values before and |
| after the call as needed. |
| |
| * Menu: |
| |
| * Open Flags:: |
| * mode_t Values:: |
| * Errno Values:: |
| * Lseek Flags:: |
| * Limits:: |
| |
| |
| File: gdb.info, Node: Open Flags, Next: mode_t Values, Up: Constants |
| |
| Open Flags |
| .......... |
| |
| All values are given in hexadecimal representation. |
| |
| O_RDONLY 0x0 |
| O_WRONLY 0x1 |
| O_RDWR 0x2 |
| O_APPEND 0x8 |
| O_CREAT 0x200 |
| O_TRUNC 0x400 |
| O_EXCL 0x800 |
| |
| |
| File: gdb.info, Node: mode_t Values, Next: Errno Values, Prev: Open Flags, Up: Constants |
| |
| mode_t Values |
| ............. |
| |
| All values are given in octal representation. |
| |
| S_IFREG 0100000 |
| S_IFDIR 040000 |
| S_IRUSR 0400 |
| S_IWUSR 0200 |
| S_IXUSR 0100 |
| S_IRGRP 040 |
| S_IWGRP 020 |
| S_IXGRP 010 |
| S_IROTH 04 |
| S_IWOTH 02 |
| S_IXOTH 01 |
| |
| |
| File: gdb.info, Node: Errno Values, Next: Lseek Flags, Prev: mode_t Values, Up: Constants |
| |
| Errno Values |
| ............ |
| |
| All values are given in decimal representation. |
| |
| EPERM 1 |
| ENOENT 2 |
| EINTR 4 |
| EBADF 9 |
| EACCES 13 |
| EFAULT 14 |
| EBUSY 16 |
| EEXIST 17 |
| ENODEV 19 |
| ENOTDIR 20 |
| EISDIR 21 |
| EINVAL 22 |
| ENFILE 23 |
| EMFILE 24 |
| EFBIG 27 |
| ENOSPC 28 |
| ESPIPE 29 |
| EROFS 30 |
| ENAMETOOLONG 91 |
| EUNKNOWN 9999 |
| |
| `EUNKNOWN' is used as a fallback error value if a host system returns |
| any error value not in the list of supported error numbers. |
| |
| |
| File: gdb.info, Node: Lseek Flags, Next: Limits, Prev: Errno Values, Up: Constants |
| |
| Lseek Flags |
| ........... |
| |
| SEEK_SET 0 |
| SEEK_CUR 1 |
| SEEK_END 2 |
| |
| |
| File: gdb.info, Node: Limits, Prev: Lseek Flags, Up: Constants |
| |
| Limits |
| ...... |
| |
| All values are given in decimal representation. |
| |
| INT_MIN -2147483648 |
| INT_MAX 2147483647 |
| UINT_MAX 4294967295 |
| LONG_MIN -9223372036854775808 |
| LONG_MAX 9223372036854775807 |
| ULONG_MAX 18446744073709551615 |
| |
| |
| File: gdb.info, Node: File-I/O Examples, Prev: Constants, Up: File-I/O Remote Protocol Extension |
| |
| E.13.10 File-I/O Examples |
| ------------------------- |
| |
| Example sequence of a write call, file descriptor 3, buffer is at target |
| address 0x1234, 6 bytes should be written: |
| |
| <- `Fwrite,3,1234,6' |
| _request memory read from target_ |
| -> `m1234,6' |
| <- XXXXXX |
| _return "6 bytes written"_ |
| -> `F6' |
| |
| Example sequence of a read call, file descriptor 3, buffer is at |
| target address 0x1234, 6 bytes should be read: |
| |
| <- `Fread,3,1234,6' |
| _request memory write to target_ |
| -> `X1234,6:XXXXXX' |
| _return "6 bytes read"_ |
| -> `F6' |
| |
| Example sequence of a read call, call fails on the host due to |
| invalid file descriptor (`EBADF'): |
| |
| <- `Fread,3,1234,6' |
| -> `F-1,9' |
| |
| Example sequence of a read call, user presses `Ctrl-c' before |
| syscall on host is called: |
| |
| <- `Fread,3,1234,6' |
| -> `F-1,4,C' |
| <- `T02' |
| |
| Example sequence of a read call, user presses `Ctrl-c' after syscall |
| on host is called: |
| |
| <- `Fread,3,1234,6' |
| -> `X1234,6:XXXXXX' |
| <- `T02' |
| |
| |
| File: gdb.info, Node: Library List Format, Next: Library List Format for SVR4 Targets, Prev: File-I/O Remote Protocol Extension, Up: Remote Protocol |
| |
| E.14 Library List Format |
| ======================== |
| |
| On some platforms, a dynamic loader (e.g. `ld.so') runs in the same |
| process as your application to manage libraries. In this case, GDB can |
| use the loader's symbol table and normal memory operations to maintain |
| a list of shared libraries. On other platforms, the operating system |
| manages loaded libraries. GDB can not retrieve the list of currently |
| loaded libraries through memory operations, so it uses the |
| `qXfer:libraries:read' packet (*note qXfer library list read::) |
| instead. The remote stub queries the target's operating system and |
| reports which libraries are loaded. |
| |
| The `qXfer:libraries:read' packet returns an XML document which |
| lists loaded libraries and their offsets. Each library has an |
| associated name and one or more segment or section base addresses, |
| which report where the library was loaded in memory. |
| |
| For the common case of libraries that are fully linked binaries, the |
| library should have a list of segments. If the target supports dynamic |
| linking of a relocatable object file, its library XML element should |
| instead include a list of allocated sections. The segment or section |
| bases are start addresses, not relocation offsets; they do not depend |
| on the library's link-time base addresses. |
| |
| GDB must be linked with the Expat library to support XML library |
| lists. *Note Expat::. |
| |
| A simple memory map, with one loaded library relocated by a single |
| offset, looks like this: |
| |
| <library-list> |
| <library name="/lib/libc.so.6"> |
| <segment address="0x10000000"/> |
| </library> |
| </library-list> |
| |
| Another simple memory map, with one loaded library with three |
| allocated sections (.text, .data, .bss), looks like this: |
| |
| <library-list> |
| <library name="sharedlib.o"> |
| <section address="0x10000000"/> |
| <section address="0x20000000"/> |
| <section address="0x30000000"/> |
| </library> |
| </library-list> |
| |
| The format of a library list is described by this DTD: |
| |
| <!-- library-list: Root element with versioning --> |
| <!ELEMENT library-list (library)*> |
| <!ATTLIST library-list version CDATA #FIXED "1.0"> |
| <!ELEMENT library (segment*, section*)> |
| <!ATTLIST library name CDATA #REQUIRED> |
| <!ELEMENT segment EMPTY> |
| <!ATTLIST segment address CDATA #REQUIRED> |
| <!ELEMENT section EMPTY> |
| <!ATTLIST section address CDATA #REQUIRED> |
| |
| In addition, segments and section descriptors cannot be mixed within |
| a single library element, and you must supply at least one segment or |
| section for each library. |
| |