| /* |
| * (c) Copyright 1990-1996 OPEN SOFTWARE FOUNDATION, INC. |
| * (c) Copyright 1990-1996 HEWLETT-PACKARD COMPANY |
| * (c) Copyright 1990-1996 DIGITAL EQUIPMENT CORPORATION |
| * (c) Copyright 1991, 1992 Siemens-Nixdorf Information Systems |
| * To anyone who acknowledges that this file is provided "AS IS" without |
| * any express or implied warranty: permission to use, copy, modify, and |
| * distribute this file for any purpose is hereby granted without fee, |
| * provided that the above copyright notices and this notice appears in |
| * all source code copies, and that none of the names listed above be used |
| * in advertising or publicity pertaining to distribution of the software |
| * without specific, written prior permission. None of these organizations |
| * makes any representations about the suitability of this software for |
| * any purpose. |
| */ |
| /* |
| * Header file for thread synchrounous I/O |
| */ |
| |
| #ifndef CMA_THREAD_IO |
| #define CMA_THREAD_IO |
| |
| /* |
| * INCLUDE FILES |
| */ |
| |
| #include <cma_config.h> |
| #include <sys/file.h> |
| #include <cma.h> |
| #include <sys/types.h> |
| #include <sys/time.h> |
| #include <cma_init.h> |
| #include <cma_errors.h> |
| |
| /* |
| * CONSTANTS |
| */ |
| |
| /* |
| * Define symbols which indicate whether to compile code for obsolete |
| * "non-blocking mode" flags: FNDELAY and FNBLOCK. If the obsolete |
| * symbols are defined, and if their replacement symbols are defined |
| * and are different or if they are undefined, then define a symbol |
| * that says to compile the code in; otherwise no code will be compiled |
| * for these obsolete symbols. |
| */ |
| #ifdef FNDELAY |
| # ifdef O_NDELAY |
| # if O_NDELAY != FNDELAY |
| # define _CMA_FNDELAY_ |
| # endif |
| # else |
| # define _CMA_FNDELAY_ |
| # endif |
| #endif |
| |
| #ifdef FNBLOCK |
| # ifdef O_NONBLOCK |
| # if O_NONBLOCK != FNBLOCK |
| # define _CMA_FNBLOCK_ |
| # endif |
| # else |
| # define _CMA_FNBLOCK_ |
| # endif |
| #endif |
| |
| |
| extern cma_t_boolean cma_is_open(int); |
| /* |
| * Maximum number of files (ie, max_fd+1) |
| */ |
| #define cma__c_mx_file FD_SETSIZE |
| |
| /* |
| * Number of bits per file descriptor bit mask (ie number of bytes * bits/byte) |
| */ |
| #define cma__c_nbpm NFDBITS |
| |
| /* |
| * TYPE DEFINITIONS |
| */ |
| |
| typedef enum CMA__T_IO_TYPE { |
| cma__c_io_read = 0, |
| cma__c_io_write = 1, |
| cma__c_io_except = 2 |
| } cma__t_io_type; |
| #define cma__c_max_io_type 2 |
| |
| /* |
| * From our local <sys/types.h>: |
| * |
| * typedef long fd_mask; |
| * |
| * typedef struct fd_set { |
| * fd_mask fds_bits[howmany(FD_SETSIZE, NFDBITS)]; |
| * } fd_set; |
| * |
| */ |
| typedef fd_mask cma__t_mask; |
| typedef fd_set cma__t_file_mask; |
| |
| |
| /* |
| * GLOBAL DATA |
| */ |
| |
| /* |
| * Maximum number of files (ie, max_fd+1) as determined by getdtablesize(). |
| */ |
| extern int cma__g_mx_file; |
| |
| /* |
| * Number of submasks (ie "int" sized chunks) per file descriptor mask as |
| * determined by getdtablesize(). |
| */ |
| extern int cma__g_nspm; |
| |
| /* |
| * MACROS |
| */ |
| |
| /* |
| * Define a constant for the errno value which indicates that the requested |
| * operation was not performed because it would block the process. |
| */ |
| # define cma__is_blocking(s) \ |
| ((s == EAGAIN) || (s == EWOULDBLOCK) || (s == EINPROGRESS) || \ |
| (s == EALREADY) || (s == EDEADLK)) |
| |
| /* |
| * It is necessary to issue an I/O function, before calling cma__io_wait() |
| * in the following cases: |
| * |
| * * This file descriptor has been set non-blocking by CMA |
| * * This file descriptor has been set non-blocking by the user. |
| */ |
| |
| #define cma__issue_io_call(fd) \ |
| ( (cma__g_file[fd]->non_blocking) || \ |
| (cma__g_file[fd]->user_fl.user_non_blocking) ) |
| |
| |
| #define cma__set_user_nonblocking(flags) \ |
| |
| /* |
| * Determine if the file is open |
| */ |
| /* |
| * If the file gets closed while waiting for the mutex cma__g_file[rfd] |
| * gets set to null. This results in a crash if NDEBUG is set to 0 |
| * since cma__int_lock tries to dereference it to set the mutex ownership |
| * after it gets the mutex. The following will still set the ownership |
| * in cma__int_lock so we'll set it back to noone if cma__g_file is null |
| * when we come back just in case it matters. It shouldn't since its no |
| * longer in use but..... |
| * Callers of this should recheck cma__g_file after the reservation to |
| * make sure continueing makes sense. |
| */ |
| #define cma__fd_reserve(rfd) \ |
| { \ |
| cma__t_int_mutex *__mutex__; \ |
| __mutex__ = cma__g_file[rfd]->mutex; \ |
| cma__int_lock (__mutex__); \ |
| if(cma__g_file[rfd] == (cma__t_file_obj *)cma_c_null_ptr) \ |
| cma__int_unlock(__mutex__); \ |
| } |
| |
| |
| /* |
| * Unreserve a file descriptor |
| */ |
| #define cma__fd_unreserve(ufd) cma__int_unlock (cma__g_file[ufd]->mutex) |
| |
| /* |
| * AND together two select file descriptor masks |
| */ |
| #define cma__fdm_and(target,a,b) \ |
| { \ |
| int __i__ = cma__g_nspm; \ |
| while (__i__--) \ |
| (target)->fds_bits[__i__] = \ |
| (a)->fds_bits[__i__] & (b)->fds_bits[__i__]; \ |
| } |
| |
| /* |
| * Clear a bit in a select file descriptor mask |
| * |
| * FD_CLR(n, p) := ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS))) |
| */ |
| #define cma__fdm_clr_bit(n,p) FD_CLR (n, p) |
| |
| /* |
| * Copy the contents of one file descriptor mask into another. If the |
| * destination operand is null, do nothing; if the source operand is null, |
| * simply zero the destination. |
| */ |
| #define cma__fdm_copy(src,dst,nfds) { \ |
| if (dst) \ |
| if (src) { \ |
| cma__t_mask *__s__ = (cma__t_mask *)(src); \ |
| cma__t_mask *__d__ = (cma__t_mask *)(dst); \ |
| int __i__; \ |
| for (__i__ = 0; __i__ < (nfds); __i__ += cma__c_nbpm) \ |
| *__d__++ = *__s__++; \ |
| } \ |
| else \ |
| cma__fdm_zero (dst); \ |
| } |
| |
| /* |
| * To increment count for each bit set in fd - mask |
| */ |
| #define cma__fdm_count_bits(map,count) \ |
| { \ |
| int __i__ = cma__g_nspm; \ |
| while (__i__--) { \ |
| cma__t_mask __tm__; \ |
| __tm__ = (map)->fds_bits[__i__]; \ |
| while(__tm__) { \ |
| (count)++; \ |
| __tm__ &= ~(__tm__ & (-__tm__)); /* Assumes 2's comp */ \ |
| } \ |
| } \ |
| } |
| |
| /* |
| * Test if a bit is set in a select file descriptor mask |
| * |
| * FD_ISSET(n,p) := ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS))) |
| */ |
| #define cma__fdm_is_set(n,p) FD_ISSET (n, p) |
| |
| /* |
| * OR together two select file descriptor masks |
| */ |
| #define cma__fdm_or(target,a,b) \ |
| { \ |
| int __i__ = cma__g_nspm; \ |
| while (__i__--) \ |
| (target)->fds_bits[__i__] = \ |
| (a)->fds_bits[__i__] | (b)->fds_bits[__i__]; \ |
| } |
| |
| /* |
| * Set a bit in a select file descriptor mask |
| * |
| * FD_SET(n,p) := ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS))) |
| */ |
| #define cma__fdm_set_bit(n,p) FD_SET (n, p) |
| |
| /* |
| * Clear a select file descriptor mask. |
| */ |
| #define cma__fdm_zero(n) \ |
| cma__memset ((char *) n, 0, cma__g_nspm * sizeof(cma__t_mask)) |
| |
| |
| |
| /* |
| * CMA "thread-synchronous" I/O read/write operations |
| */ |
| |
| /* |
| * Since all CMA "thread-synchronous" I/O (read or write) operations on |
| * U*ix follow the exact same structure, the wrapper routines have been |
| * condensed into a macro. |
| * |
| * The steps performed are as follows: |
| * 1. Check that the file descriptor is a legitimate value. |
| * 2. Check that the entry in the CMA file "database" which corresponds to |
| * the file descriptor indicates that the "file" was "opened" by CMA. |
| * 3. Reserve the file, to serialized access to files. This not only |
| * simplifies things, but also defends against non-reentrancy. |
| * 4. If the "file" is "set" for non-blocking I/O, check if we |
| * have actually set the file non-blocking yet, and if not do so. |
| * Then, issue the I/O operantion. |
| * Success or failure is returned immediately, after unreserving the |
| * file. If the error indicates that the operation would have caused |
| * the process to block, continue to the next step. |
| * 5. The I/O prolog adds this "file" to the global bit mask, which |
| * represents all "files" which have threads waiting to perform I/O on |
| * them, and causes the thread to block on the condition variable for |
| * this "file". Periodically, a select is done on this global bit |
| * mask, and the condition variables corresponding to "files" which |
| * are ready for I/O are signaled, releasing those waiting threads to |
| * perform their I/O. |
| * 6. When the thread returns from the I/O prolog, it can (hopefully) |
| * perform its operation without blocking the process. |
| * 7. The I/O epilog clears the bit in the global mask and/or signals the |
| * the next thread waiting for this "file", as appropriate. |
| * 8. If the I/O failed, continue to loop. |
| * 9. Finally, the "file" is unreserved, as we're done with it, and the |
| * result of the operation is returned. |
| * |
| * |
| * Note: currently, we believe that timeslicing which is based on the |
| * virtual-time timer does not cause system calls to return EINTR. |
| * Threfore, any EINTR returns are relayed directly to the caller. |
| * On platforms which do not support a virtual-time timer, the code |
| * should probably catch EINTR returns and restart the system call. |
| */ |
| |
| /* |
| * This macro is used for both read-type and write-type functions. |
| * |
| * Note: the second call to "func" may require being bracketed in a |
| * cma__interrupt_disable/cma__interrupt_enable pair, but we'll |
| * wait and see if this is necessary. |
| */ |
| #define cma__ts_func(func,fd,arglist,type,post_process) { \ |
| cma_t_integer __res__; \ |
| cma_t_boolean __done__ = cma_c_false; \ |
| if ((fd < 0) || (fd >= cma__g_mx_file)) return (cma__set_errno (EBADF), -1); \ |
| if (!cma__is_open(fd)) return (cma__set_errno (EBADF), -1); \ |
| cma__fd_reserve (fd); \ |
| if (!cma__is_open(fd)) return (cma__set_errno (EBADF), -1); \ |
| if (cma__issue_io_call(fd)) {\ |
| if ((!cma__g_file[fd]->set_non_blocking) && \ |
| (cma__g_file[fd]->non_blocking == cma_c_true)) \ |
| cma__set_nonblocking(fd); \ |
| cma__interrupt_disable (0); \ |
| TRY { \ |
| __res__ = func arglist; \ |
| } \ |
| CATCH_ALL { \ |
| cma__interrupt_enable (0); \ |
| cma__fd_unreserve (fd); \ |
| RERAISE; \ |
| } \ |
| ENDTRY \ |
| cma__interrupt_enable (0); \ |
| if ((__res__ != -1) \ |
| || (!cma__is_blocking (errno)) \ |
| || (cma__g_file[fd]->user_fl.user_non_blocking)) \ |
| __done__ = cma_c_true; \ |
| } \ |
| if (__done__) { \ |
| cma__fd_unreserve (fd); \ |
| } \ |
| else { \ |
| TRY { \ |
| cma__io_prolog (type, fd); \ |
| while (!__done__) { \ |
| cma__io_wait (type, fd); \ |
| __res__ = func arglist; \ |
| if ((__res__ != -1) \ |
| || (!cma__is_blocking (errno)) \ |
| || (cma__g_file[fd]->user_fl.user_non_blocking)) \ |
| __done__ = cma_c_true; \ |
| } \ |
| } \ |
| FINALLY { \ |
| cma__io_epilog (type, fd); \ |
| cma__fd_unreserve (fd); \ |
| } \ |
| ENDTRY \ |
| } \ |
| if (__res__ != -1) post_process; \ |
| return __res__; \ |
| } |
| |
| /* |
| * Since most CMA "thread-synchronous" I/O ("open"-type) operations on |
| * U*ix follow the exact same structure, the wrapper routines have been |
| * condensed into a macro. |
| * |
| * The steps performed are as follows: |
| * 1. Issue the open function. |
| * 2. If the value returned indicates an error, return it to the caller. |
| * 3. If the file descriptor returned is larger than what we think is the |
| * maximum value (ie if it is too big for our database) then bugcheck. |
| * 4. "Open" the "file" in the CMA file database. |
| * 5. Return the file descriptor value to the caller. |
| * |
| * FIX-ME: for the time being, if the I/O operation returns EINTR, we |
| * simply return it to the caller; eventually, we should catch this |
| * and "do the right thing" (if we can figure out what that is). |
| */ |
| |
| /* |
| * This macro is used for all "open"-type functions which return a single file |
| * desciptor by immediate value. |
| */ |
| #define cma__ts_open(func,arglist,post_process) { \ |
| int __fd__; \ |
| TRY { \ |
| cma__int_init (); \ |
| cma__int_lock (cma__g_io_data_mutex); \ |
| __fd__ = func arglist; \ |
| cma__int_unlock (cma__g_io_data_mutex); \ |
| if (__fd__ >= 0 && __fd__ < cma__g_mx_file) \ |
| post_process; \ |
| } \ |
| CATCH_ALL \ |
| { \ |
| cma__set_errno (EBADF); \ |
| __fd__ = -1; \ |
| } \ |
| ENDTRY \ |
| if (__fd__ >= cma__g_mx_file) \ |
| cma__bugcheck ("cma__ts_open: fd is too large"); \ |
| return __fd__; \ |
| } |
| /* |
| * This macro is used for all "open"-type functions which return a pair of file |
| * desciptors by reference parameter. |
| */ |
| #define cma__ts_open2(func,fdpair,arglist,post_process) { \ |
| int __res__; \ |
| TRY { \ |
| cma__int_init (); \ |
| cma__int_lock (cma__g_io_data_mutex); \ |
| __res__ = func arglist; \ |
| cma__int_unlock (cma__g_io_data_mutex); \ |
| if (__res__ >= 0 && fdpair[0] < cma__g_mx_file \ |
| && fdpair[1] < cma__g_mx_file) \ |
| post_process; \ |
| } \ |
| CATCH_ALL \ |
| { \ |
| cma__set_errno (EBADF); \ |
| __res__ = -1; \ |
| } \ |
| ENDTRY \ |
| if ((fdpair[0] >= cma__g_mx_file) || (fdpair[1] >= cma__g_mx_file)) \ |
| cma__bugcheck ("cma__ts_open2: one of fd's is too large"); \ |
| return __res__; \ |
| } |
| |
| /* |
| * INTERNAL INTERFACES |
| */ |
| extern void cma__close_general (int); |
| |
| extern void cma__init_thread_io (void); |
| |
| extern cma_t_boolean cma__io_available (cma__t_io_type,int,struct timeval *); |
| |
| extern void cma__io_epilog (cma__t_io_type,int); |
| |
| extern void cma__io_prolog (cma__t_io_type,int); |
| |
| extern void cma__io_wait (cma__t_io_type,int); |
| |
| extern void cma__open_general (int); |
| |
| extern void cma__reinit_thread_io (int); |
| |
| extern void cma__set_nonblocking (int); |
| |
| extern void cma__set_user_nonblock_flags (int,int); |
| |
| extern cma_t_boolean cma__is_open (int); |
| |
| |
| #endif |