newlib/newlib/libc/sys/linux/include/link.h - native_client/nacl-toolchain - Git at Google

 /* Data structure for communication from the run-time dynamic linker for
    loaded ELF shared objects.
    Copyright (C) 1995-1999, 2000, 2001 Free Software Foundation, Inc.
    This file is part of the GNU C Library.

    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    The GNU C Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; if not, write to the Free
    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
    02111-1307 USA.  */

 #ifndef	_LINK_H
 #define	_LINK_H	1

 #include <features.h>
 #include <elf.h>
 #include <dlfcn.h>
 #include <sys/types.h>

 #define DT_THISPROCNUM 0
 /* We use this macro to refer to ELF types independent of the native wordsize.
    `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'.  */
 #define ElfW(type)	_ElfW (Elf, __ELF_NATIVE_CLASS, type)
 #define _ElfW(e,w,t)	_ElfW_1 (e, w, _##t)
 #define _ElfW_1(e,w,t)	e##w##t

 #include <sys/elfclass.h>		/* Defines __ELF_NATIVE_CLASS.  */
 #include <sys/link.h>
 #include <dl-lookupcfg.h>

 /* Rendezvous structure used by the run-time dynamic linker to communicate
    details of shared object loading to the debugger.  If the executable's
    dynamic section has a DT_DEBUG element, the run-time linker sets that
    element's value to the address where this structure can be found.  */

 struct r_debug
   {
     int r_version;		/* Version number for this protocol.  */

     struct link_map *r_map;	/* Head of the chain of loaded objects.  */

     /* This is the address of a function internal to the run-time linker,
        that will always be called when the linker begins to map in a
        library or unmap it, and again when the mapping change is complete.
        The debugger can set a breakpoint at this address if it wants to
        notice shared object mapping changes.  */
     ElfW(Addr) r_brk;
     enum
       {
 	/* This state value describes the mapping change taking place when
 	   the `r_brk' address is called.  */
 	RT_CONSISTENT,		/* Mapping change is complete.  */
 	RT_ADD,			/* Beginning to add a new object.  */
 	RT_DELETE		/* Beginning to remove an object mapping.  */
       } r_state;

     ElfW(Addr) r_ldbase;	/* Base address the linker is loaded at.  */
   };

 /* This is the instance of that structure used by the dynamic linker.  */
 extern struct r_debug _r_debug;

 /* This symbol refers to the "dynamic structure" in the `.dynamic' section
    of whatever module refers to `_DYNAMIC'.  So, to find its own
    `struct r_debug', a program could do:
      for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn)
        if (dyn->d_tag == DT_DEBUG)
 	 r_debug = (struct r_debug *) dyn->d_un.d_ptr;
    */
 extern ElfW(Dyn) _DYNAMIC[];


 /* Some internal data structures of the dynamic linker used in the
    linker map.  We only provide forward declarations.  */
 struct libname_list;
 struct r_found_version;
 struct r_search_path_elem;

 /* Forward declaration.  */
 struct link_map;

 /* Structure to describe a single list of scope elements.  The lookup
    functions get passed an array of pointers to such structures.  */
 struct r_scope_elem
 {
   /* Array of maps for the scope.  */
   struct link_map **r_list;
   /* Number of entries in the scope.  */
   unsigned int r_nlist;
 };


 /* Structure to record search path and allocation mechanism.  */
 struct r_search_path_struct
   {
     struct r_search_path_elem **dirs;
     int malloced;
   };


 /* Structure describing a loaded shared object.  The `l_next' and `l_prev'
    members form a chain of all the shared objects loaded at startup.

    These data structures exist in space used by the run-time dynamic linker;
    modifying them may have disastrous results.

    This data structure might change in future, if necessary.  User-level
    programs must avoid defining objects of this type.  */

 struct link_map
   {
     /* These first few members are part of the protocol with the debugger.
        This is the same format used in SVR4.  */

     ElfW(Addr) l_addr;		/* Base address shared object is loaded at.  */
     char *l_name;		/* Absolute file name object was found in.  */
     ElfW(Dyn) *l_ld;		/* Dynamic section of the shared object.  */
     struct link_map *l_next, *l_prev; /* Chain of loaded objects.  */

     /* All following members are internal to the dynamic linker.
        They may change without notice.  */

     struct libname_list *l_libname;
     /* Indexed pointers to dynamic section.
        [0,DT_NUM) are indexed by the processor-independent tags.
        [DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC.
        [DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_EXTRANUM) are indexed
        by DT_EXTRATAGIDX(tagvalue) and
        [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM,
         DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM)
        are indexed by DT_EXTRATAGIDX(tagvalue) (see <elf.h>).  */

     ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM
 		     + DT_EXTRANUM];
     const ElfW(Phdr) *l_phdr;	/* Pointer to program header table in core.  */
     ElfW(Addr) l_entry;		/* Entry point location.  */
     ElfW(Half) l_phnum;		/* Number of program header entries.  */
     ElfW(Half) l_ldnum;	/* Number of dynamic segment entries.  */

     /* Array of DT_NEEDED dependencies and their dependencies, in
        dependency order for symbol lookup (with and without
        duplicates).  There is no entry before the dependencies have
        been loaded.  */
     struct r_scope_elem l_searchlist;

     /* We need a special searchlist to process objects marked with
        DT_SYMBOLIC.  */
     struct r_scope_elem l_symbolic_searchlist;

     /* Dependent object that first caused this object to be loaded.  */
     struct link_map *l_loader;

     /* Symbol hash table.  */
     Elf_Symndx l_nbuckets;
     const Elf_Symndx *l_buckets, *l_chain;

     unsigned int l_opencount;	/* Reference count for dlopen/dlclose.  */
     enum			/* Where this object came from.  */
       {
 	lt_executable,		/* The main executable program.  */
 	lt_library,		/* Library needed by main executable.  */
 	lt_loaded		/* Extra run-time loaded shared object.  */
       } l_type:2;
     unsigned int l_relocated:1;	/* Nonzero if object's relocations done.  */
     unsigned int l_init_called:1; /* Nonzero if DT_INIT function called.  */
     unsigned int l_global:1;	/* Nonzero if object in _dl_global_scope.  */
     unsigned int l_reserved:2;	/* Reserved for internal use.  */
     unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed
 					to by `l_phdr' is allocated.  */
     unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in
 				      the l_libname list.  */
     unsigned int l_faked:1;	/* Nonzero if this is a faked descriptor
 				   without associated file.  */

     /* Array with version names.  */
     unsigned int l_nversions;
     struct r_found_version *l_versions;

     /* Collected information about own RPATH directories.  */
     struct r_search_path_struct l_rpath_dirs;

     /* Collected results of relocation while profiling.  */
     ElfW(Addr) *l_reloc_result;

     /* Pointer to the version information if available.  */
     ElfW(Versym) *l_versyms;

     /* String specifying the path where this object was found.  */
     const char *l_origin;

     /* Start and finish of memory map for this object.  l_map_start
        need not be the same as l_addr.  */
     ElfW(Addr) l_map_start, l_map_end;

     /* Default array for 'l_scope'.  */
     struct r_scope_elem *l_scope_mem[4];
     /* Size of array allocated for 'l_scope'.  */
     size_t l_scope_max;
     /* This is an array defining the lookup scope for this link map.
        There are at most three different scope lists.  */
     struct r_scope_elem **l_scope;

     /* A similar array, this time only with the local scope.  This is
        used occasionally.  */
     struct r_scope_elem *l_local_scope[2];

     /* This information is kept to check for sure whether a shared
        object is the same as one already loaded.  */
     dev_t l_dev;
     ino64_t l_ino;

     /* Collected information about own RUNPATH directories.  */
     struct r_search_path_struct l_runpath_dirs;

     /* List of object in order of the init and fini calls.  */
     struct link_map **l_initfini;

     /* List of the dependencies introduced through symbol binding.  */
     unsigned int l_reldepsmax;
     unsigned int l_reldepsact;
     struct link_map **l_reldeps;

     /* Various flag words.  */
     ElfW(Word) l_feature_1;
     ElfW(Word) l_flags_1;

     /* Temporarily used in `dl_close'.  */
     unsigned int l_idx;

     struct link_map_machine l_mach;

     struct
     {
       const ElfW(Sym) *sym;
       int type_class;
 #ifdef DL_LOOKUP_RETURNS_MAP
       struct link_map *value;
 #else
       ElfW(Addr) value;
 #endif
       const ElfW(Sym) *ret;
     } l_lookup_cache;
   };

 struct dl_phdr_info
   {
     ElfW(Addr) dlpi_addr;
     const char *dlpi_name;
     const ElfW(Phdr) *dlpi_phdr;
     ElfW(Half) dlpi_phnum;
   };

 extern int dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
 					     size_t size, void *data),
 			    void *data);
 extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info,
 					       size_t size, void *data),
 			      void *data);

 #endif /* link.h */
	/* Data structure for communication from the run-time dynamic linker for
	loaded ELF shared objects.
	Copyright (C) 1995-1999, 2000, 2001 Free Software Foundation, Inc.
	This file is part of the GNU C Library.

	The GNU C Library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	The GNU C Library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with the GNU C Library; if not, write to the Free
	Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
	02111-1307 USA. */

	#ifndef _LINK_H
	#define _LINK_H 1

	#include <features.h>
	#include <elf.h>
	#include <dlfcn.h>
	#include <sys/types.h>

	#define DT_THISPROCNUM 0
	/* We use this macro to refer to ELF types independent of the native wordsize.
	`ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
	#define ElfW(type) _ElfW (Elf, __ELF_NATIVE_CLASS, type)
	#define _ElfW(e,w,t) _ElfW_1 (e, w, _##t)
	#define _ElfW_1(e,w,t) e##w##t

	#include <sys/elfclass.h> /* Defines __ELF_NATIVE_CLASS. */
	#include <sys/link.h>
	#include <dl-lookupcfg.h>

	/* Rendezvous structure used by the run-time dynamic linker to communicate
	details of shared object loading to the debugger. If the executable's
	dynamic section has a DT_DEBUG element, the run-time linker sets that
	element's value to the address where this structure can be found. */

	struct r_debug
	{
	int r_version; /* Version number for this protocol. */

	struct link_map r_map; / Head of the chain of loaded objects. */

	/* This is the address of a function internal to the run-time linker,
	that will always be called when the linker begins to map in a
	library or unmap it, and again when the mapping change is complete.
	The debugger can set a breakpoint at this address if it wants to
	notice shared object mapping changes. */
	ElfW(Addr) r_brk;
	enum
	{
	/* This state value describes the mapping change taking place when
	the `r_brk' address is called. */
	RT_CONSISTENT, /* Mapping change is complete. */
	RT_ADD, /* Beginning to add a new object. */
	RT_DELETE /* Beginning to remove an object mapping. */
	} r_state;

	ElfW(Addr) r_ldbase; /* Base address the linker is loaded at. */
	};

	/* This is the instance of that structure used by the dynamic linker. */
	extern struct r_debug _r_debug;

	/* This symbol refers to the "dynamic structure" in the `.dynamic' section
	of whatever module refers to `_DYNAMIC'. So, to find its own
	`struct r_debug', a program could do:
	for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn)
	if (dyn->d_tag == DT_DEBUG)
	r_debug = (struct r_debug *) dyn->d_un.d_ptr;
	*/
	extern ElfW(Dyn) _DYNAMIC[];


	/* Some internal data structures of the dynamic linker used in the
	linker map. We only provide forward declarations. */
	struct libname_list;
	struct r_found_version;
	struct r_search_path_elem;

	/* Forward declaration. */
	struct link_map;

	/* Structure to describe a single list of scope elements. The lookup
	functions get passed an array of pointers to such structures. */
	struct r_scope_elem
	{
	/* Array of maps for the scope. */
	struct link_map **r_list;
	/* Number of entries in the scope. */
	unsigned int r_nlist;
	};


	/* Structure to record search path and allocation mechanism. */
	struct r_search_path_struct
	{
	struct r_search_path_elem **dirs;
	int malloced;
	};


	/* Structure describing a loaded shared object. The `l_next' and `l_prev'
	members form a chain of all the shared objects loaded at startup.

	These data structures exist in space used by the run-time dynamic linker;
	modifying them may have disastrous results.

	This data structure might change in future, if necessary. User-level
	programs must avoid defining objects of this type. */

	struct link_map
	{
	/* These first few members are part of the protocol with the debugger.
	This is the same format used in SVR4. */

	ElfW(Addr) l_addr; /* Base address shared object is loaded at. */
	char l_name; / Absolute file name object was found in. */
	ElfW(Dyn) l_ld; / Dynamic section of the shared object. */
	struct link_map l_next, l_prev; /* Chain of loaded objects. */

	/* All following members are internal to the dynamic linker.
	They may change without notice. */

	struct libname_list *l_libname;
	/* Indexed pointers to dynamic section.
	[0,DT_NUM) are indexed by the processor-independent tags.
	[DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC.
	[DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_EXTRANUM) are indexed
	by DT_EXTRATAGIDX(tagvalue) and
	[DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM,
	DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM)
	are indexed by DT_EXTRATAGIDX(tagvalue) (see <elf.h>). */

	ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM
	+ DT_EXTRANUM];
	const ElfW(Phdr) l_phdr; / Pointer to program header table in core. */
	ElfW(Addr) l_entry; /* Entry point location. */
	ElfW(Half) l_phnum; /* Number of program header entries. */
	ElfW(Half) l_ldnum; /* Number of dynamic segment entries. */

	/* Array of DT_NEEDED dependencies and their dependencies, in
	dependency order for symbol lookup (with and without
	duplicates). There is no entry before the dependencies have
	been loaded. */
	struct r_scope_elem l_searchlist;

	/* We need a special searchlist to process objects marked with
	DT_SYMBOLIC. */
	struct r_scope_elem l_symbolic_searchlist;

	/* Dependent object that first caused this object to be loaded. */
	struct link_map *l_loader;

	/* Symbol hash table. */
	Elf_Symndx l_nbuckets;
	const Elf_Symndx l_buckets, l_chain;

	unsigned int l_opencount; /* Reference count for dlopen/dlclose. */
	enum /* Where this object came from. */
	{
	lt_executable, /* The main executable program. */
	lt_library, /* Library needed by main executable. */
	lt_loaded /* Extra run-time loaded shared object. */
	} l_type:2;
	unsigned int l_relocated:1; /* Nonzero if object's relocations done. */
	unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */
	unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */
	unsigned int l_reserved:2; /* Reserved for internal use. */
	unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed
	to by `l_phdr' is allocated. */
	unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in
	the l_libname list. */
	unsigned int l_faked:1; /* Nonzero if this is a faked descriptor
	without associated file. */

	/* Array with version names. */
	unsigned int l_nversions;
	struct r_found_version *l_versions;

	/* Collected information about own RPATH directories. */
	struct r_search_path_struct l_rpath_dirs;

	/* Collected results of relocation while profiling. */
	ElfW(Addr) *l_reloc_result;

	/* Pointer to the version information if available. */
	ElfW(Versym) *l_versyms;

	/* String specifying the path where this object was found. */
	const char *l_origin;

	/* Start and finish of memory map for this object. l_map_start
	need not be the same as l_addr. */
	ElfW(Addr) l_map_start, l_map_end;

	/* Default array for 'l_scope'. */
	struct r_scope_elem *l_scope_mem[4];
	/* Size of array allocated for 'l_scope'. */
	size_t l_scope_max;
	/* This is an array defining the lookup scope for this link map.
	There are at most three different scope lists. */
	struct r_scope_elem **l_scope;

	/* A similar array, this time only with the local scope. This is
	used occasionally. */
	struct r_scope_elem *l_local_scope[2];

	/* This information is kept to check for sure whether a shared
	object is the same as one already loaded. */
	dev_t l_dev;
	ino64_t l_ino;

	/* Collected information about own RUNPATH directories. */
	struct r_search_path_struct l_runpath_dirs;

	/* List of object in order of the init and fini calls. */
	struct link_map **l_initfini;

	/* List of the dependencies introduced through symbol binding. */
	unsigned int l_reldepsmax;
	unsigned int l_reldepsact;
	struct link_map **l_reldeps;

	/* Various flag words. */
	ElfW(Word) l_feature_1;
	ElfW(Word) l_flags_1;

	/* Temporarily used in `dl_close'. */
	unsigned int l_idx;

	struct link_map_machine l_mach;

	struct
	{
	const ElfW(Sym) *sym;
	int type_class;
	#ifdef DL_LOOKUP_RETURNS_MAP
	struct link_map *value;
	#else
	ElfW(Addr) value;
	#endif
	const ElfW(Sym) *ret;
	} l_lookup_cache;
	};

	struct dl_phdr_info
	{
	ElfW(Addr) dlpi_addr;
	const char *dlpi_name;
	const ElfW(Phdr) *dlpi_phdr;
	ElfW(Half) dlpi_phnum;
	};

	extern int dl_iterate_phdr (int (callback) (struct dl_phdr_info info,
	size_t size, void *data),
	void *data);
	extern int __dl_iterate_phdr (int (callback) (struct dl_phdr_info info,
	size_t size, void *data),
	void *data);

	#endif /* link.h */