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glibc/elf/ldsodefs.h

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/* Run-time dynamic linker data structures for loaded ELF shared objects.
Copyright (C) 1995, 1996, 1997, 1998 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifndef _LDSODEFS_H
#define _LDSODEFS_H 1
#include <features.h>
#define __need_size_t
#define __need_NULL
#include <stddef.h>
#include <elf.h>
#include <dlfcn.h>
#include <link.h>
__BEGIN_DECLS
/* 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)
/* For the version handling we need an array with only names and their
hash values. */
struct r_found_version
{
const char *name;
ElfW(Word) hash;
int hidden;
const char *filename;
};
/* We want to cache information about the searches for shared objects. */
enum r_dir_status { unknown, nonexisting, existing };
struct r_search_path_elem
{
const char *dirname;
size_t dirnamelen;
enum r_dir_status dirstatus;
size_t machdirnamelen;
enum r_dir_status machdirstatus;
/* Strings saying where the definition came from. */
const char *what;
const char *where;
/* This link is only used in the `all_dirs' member of `r_search_path'. */
struct r_search_path_elem *next;
};
/* A data structure for a simple single linked list of strings. */
struct libname_list
{
const char *name; /* Name requested (before search). */
struct libname_list *next; /* Link to next name for this object. */
};
/* Test whether given NAME matches any of the names of the given object. */
static __inline int
__attribute__ ((unused))
_dl_name_match_p (const char *__name, struct link_map *__map)
{
int __found = strcmp (__name, __map->l_name) == 0;
struct libname_list *__runp = __map->l_libname;
while (! __found && __runp != NULL)
if (strcmp (__name, __runp->name) == 0)
__found = 1;
else
__runp = __runp->next;
return __found;
}
/* Function used as argument for `_dl_receive_error' function. The
arguments are the error code, error string, and the objname the
error occurred in. */
typedef void (*receiver_fct) (int, const char *, const char *);
/* Internal functions of the run-time dynamic linker.
These can be accessed if you link again the dynamic linker
as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
but are not normally of interest to user programs.
The `-ldl' library functions in <dlfcn.h> provide a simple
user interface to run-time dynamic linking. */
/* Parameters passed to the dynamic linker. */
extern char **_dl_argv;
/* Cached value of `getpagesize ()'. */
extern size_t _dl_pagesize;
/* File descriptor referring to the zero-fill device. */
extern int _dl_zerofd;
/* Name of the shared object to be profiled (if any). */
extern const char *_dl_profile;
/* Map of shared object to be profiled. */
extern struct link_map *_dl_profile_map;
/* If nonzero the appropriate debug information is printed. */
extern int _dl_debug_libs;
extern int _dl_debug_impcalls;
extern int _dl_debug_bindings;
extern int _dl_debug_symbols;
extern int _dl_debug_versions;
extern int _dl_debug_reloc;
extern int _dl_debug_files;
/* Expect cache ID. */
extern int _dl_correct_cache_id;
/* File deccriptor to write debug messages to. */
extern int _dl_debug_fd;
/* OS-dependent function to open the zero-fill device. */
extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
/* OS-dependent function to write a message on the specified
descriptor FD. All arguments are `const char *'; args until a null
pointer are concatenated to form the message to print. */
extern void _dl_sysdep_output (int fd, const char *string, ...);
/* OS-dependent function to write a debug message on the specified
descriptor for this. All arguments are `const char *'; args until
a null pointer are concatenated to form the message to print. If
NEW_LINE is nonzero it is assumed that the message starts on a new
line.*/
extern void _dl_debug_message (int new_line, const char *string, ...);
/* OS-dependent function to write a message on the standard output.
All arguments are `const char *'; args until a null pointer
are concatenated to form the message to print. */
#define _dl_sysdep_message(string, args...) \
_dl_sysdep_output (STDOUT_FILENO, string, ##args)
/* OS-dependent function to write a message on the standard error.
All arguments are `const char *'; args until a null pointer
are concatenated to form the message to print. */
#define _dl_sysdep_error(string, args...) \
_dl_sysdep_output (STDERR_FILENO, string, ##args)
/* OS-dependent function to give a fatal error message and exit
when the dynamic linker fails before the program is fully linked.
All arguments are `const char *'; args until a null pointer
are concatenated to form the message to print. */
#define _dl_sysdep_fatal(string, args...) \
do \
{ \
_dl_sysdep_output (STDERR_FILENO, string, ##args); \
_exit (127); \
} \
while (1)
/* Nonzero if the program should be "secure" (i.e. it's setuid or somesuch).
This tells the dynamic linker to ignore environment variables. */
extern int _dl_secure;
/* This function is called by all the internal dynamic linker functions
when they encounter an error. ERRCODE is either an `errno' code or
zero; OBJECT is the name of the problematical shared object, or null if
it is a general problem; ERRSTRING is a string describing the specific
problem. */
extern void _dl_signal_error (int errcode,
const char *object,
const char *errstring);
/* Call OPERATE, catching errors from `dl_signal_error'. If there is no
error, *ERRSTRING is set to null. If there is an error, *ERRSTRING is
set to a string constructed from the strings passed to _dl_signal_error,
and the error code passed is the return value. ERRSTRING if nonzero
points to a malloc'ed string which the caller has to free after use.
ARGS is passed as argument to OPERATE. */
extern int _dl_catch_error (char **errstring,
void (*operate) (void *),
void *args);
/* Call OPERATE, receiving errors from `dl_signal_error'. Unlike
`_dl_catch_error' the operation is resumed after the OPERATE
function returns.
ARGS is passed as argument to OPERATE. */
extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
void *args);
/* Helper function for <dlfcn.h> functions. Runs the OPERATE function via
_dl_catch_error. Returns zero for success, nonzero for failure; and
arranges for `dlerror' to return the error details.
ARGS is passed as argument to OPERATE. */
extern int _dlerror_run (void (*operate) (void *), void *args);
/* Open the shared object NAME and map in its segments.
LOADER's DT_RPATH is used in searching for NAME.
If the object is already opened, returns its existing map.
For preloaded shared objects PRELOADED is set to a non-zero
value to allow additional security checks. */
extern struct link_map *_dl_map_object (struct link_map *loader,
const char *name, int preloaded,
int type, int trace_mode);
/* Call _dl_map_object on the dependencies of MAP, and set up
MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
loaded objects that will be inserted into MAP->l_searchlist after MAP
but before its dependencies. */
extern void _dl_map_object_deps (struct link_map *map,
struct link_map **preloads,
unsigned int npreloads, int trace_mode);
/* Cache the locations of MAP's hash table. */
extern void _dl_setup_hash (struct link_map *map);
/* Open the shared object NAME, relocate it, and run its initializer if it
hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
the object is already opened, returns its existing map. */
extern struct link_map *_dl_open (const char *name, int mode);
/* Close an object previously opened by _dl_open. */
extern void _dl_close (struct link_map *map);
/* Search loaded objects' symbol tables for a definition of the symbol
referred to by UNDEF. *SYM is the symbol table entry containing the
reference; it is replaced with the defining symbol, and the base load
address of the defining object is returned. SYMBOL_SCOPE is a
null-terminated list of object scopes to search; each object's
l_searchlist (i.e. the segment of the dependency tree starting at that
object) is searched in turn. REFERENCE_NAME should name the object
containing the reference; it is used in error messages.
RELOC_TYPE is a machine-dependent reloc type, which is passed to
the `elf_machine_lookup_*_p' macros in dl-machine.h to affect which
symbols can be chosen. */
extern ElfW(Addr) _dl_lookup_symbol (const char *undef,
const ElfW(Sym) **sym,
struct link_map *symbol_scope[],
const char *reference_name,
int reloc_type);
/* Lookup versioned symbol. */
extern ElfW(Addr) _dl_lookup_versioned_symbol (const char *undef,
const ElfW(Sym) **sym,
struct link_map *symbol_scope[],
const char *reference_name,
const struct r_found_version *version,
int reloc_type);
/* For handling RTLD_NEXT we must be able to skip shared objects. */
extern ElfW(Addr) _dl_lookup_symbol_skip (const char *undef,
const ElfW(Sym) **sym,
struct link_map *symbol_scope[],
const char *reference_name,
struct link_map *skip_this);
/* For handling RTLD_NEXT with versioned symbols we must be able to
skip shared objects. */
extern ElfW(Addr) _dl_lookup_versioned_symbol_skip (const char *undef,
const ElfW(Sym) **sym,
struct link_map *symbol_scope[],
const char *reference_name,
const struct r_found_version *version,
struct link_map *skip_this);
/* Locate shared object containing the given address. */
extern int _dl_addr (const void *address, Dl_info *info);
/* Look up symbol NAME in MAP's scope and return its run-time address. */
extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name);
/* Structure describing the dynamic linker itself. */
extern struct link_map _dl_rtld_map;
/* The list of objects currently loaded is the third element of the
`_dl_default_scope' array, and the fourth element is always null.
This leaves two slots before it that are used when resolving
DT_SYMBOLIC objects' references one after it for normal references
(see below). */
#define _dl_loaded (_dl_default_scope[2])
extern struct link_map *_dl_default_scope[5];
/* Null-terminated list of objects in the dynamic `global scope'. The
list starts at [2]; i.e. &_dl_global_scope[2] is the argument
passed to _dl_lookup_symbol to search the global scope. To search
a specific object and its dependencies in preference to the global
scope, fill in the [1] slot and pass its address; for two specific
object scopes, fill [0] and [1]. The list is double-terminated; to
search the global scope and then a specific object and its
dependencies, set *_dl_global_scope_end. This variable initially
points to _dl_default_scope, and _dl_loaded is always kept in [2]
of this list. A new list is malloc'd when new objects are loaded
with RTLD_GLOBAL. */
extern struct link_map **_dl_global_scope, **_dl_global_scope_end;
extern size_t _dl_global_scope_alloc; /* Number of slots malloc'd. */
/* Hack _dl_global_scope[0] and [1] as necessary, and return a pointer into
_dl_global_scope that should be passed to _dl_lookup_symbol for symbol
references made in the object MAP's relocations. */
extern struct link_map **_dl_object_relocation_scope (struct link_map *map);
/* Allocate a `struct link_map' for a new object being loaded,
and enter it into the _dl_loaded list. */
extern struct link_map *_dl_new_object (char *realname, const char *libname,
int type);
/* Relocate the given object (if it hasn't already been).
SCOPE is passed to _dl_lookup_symbol in symbol lookups.
If LAZY is nonzero, don't relocate its PLT. */
extern void _dl_relocate_object (struct link_map *map,
struct link_map *scope[],
int lazy);
/* Check the version dependencies of all objects available through
MAP. If VERBOSE print some more diagnostics. */
extern int _dl_check_all_versions (struct link_map *map, int verbose);
/* Check the version dependencies for MAP. If VERBOSE print some more
diagnostics. */
extern int _dl_check_map_versions (struct link_map *map, int verbose);
/* Return the address of the next initializer function for MAP or one of
its dependencies that has not yet been run. When there are no more
initializers to be run, this returns zero. The functions are returned
in the order they should be called. */
extern ElfW(Addr) _dl_init_next (struct link_map *map);
/* Call the finalizer functions of all shared objects whose
initializer functions have completed. */
extern void _dl_fini (void);
/* The dynamic linker calls this function before and having changing
any shared object mappings. The `r_state' member of `struct r_debug'
says what change is taking place. This function's address is
the value of the `r_brk' member. */
extern void _dl_debug_state (void);
/* Initialize `struct r_debug' if it has not already been done. The
argument is the run-time load address of the dynamic linker, to be put
in the `r_ldbase' member. Returns the address of the structure. */
extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase);
/* Initialize the basic data structure for the search paths. */
extern void _dl_init_paths (const char *library_path);
/* Gather the information needed to install the profiling tables and start
the timers. */
extern void _dl_start_profile (struct link_map *map, const char *output_dir);
/* The actual functions used to keep book on the calls. */
extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
/* Show the members of the auxiliary array passed up from the kernel. */
extern void _dl_show_auxv (void);
/* Return all environment variables starting with `LD_', one after the
other. */
extern char *_dl_next_ld_env_entry (char ***position);
__END_DECLS
#endif /* ldsodefs.h */
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