mirror of git://sourceware.org/git/glibc.git
448 lines
17 KiB
C
448 lines
17 KiB
C
/* Run-time dynamic linker data structures for loaded ELF shared objects.
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Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#ifndef _LDSODEFS_H
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#define _LDSODEFS_H 1
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#include <features.h>
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#define __need_size_t
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#define __need_NULL
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#include <stddef.h>
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#include <elf.h>
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#include <dlfcn.h>
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#include <link.h>
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__BEGIN_DECLS
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/* We use this macro to refer to ELF types independent of the native wordsize.
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`ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
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#define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
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/* For the version handling we need an array with only names and their
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hash values. */
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struct r_found_version
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{
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const char *name;
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ElfW(Word) hash;
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int hidden;
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const char *filename;
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};
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/* We want to cache information about the searches for shared objects. */
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enum r_dir_status { unknown, nonexisting, existing };
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struct r_search_path_elem
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{
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/* This link is only used in the `all_dirs' member of `r_search_path'. */
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struct r_search_path_elem *next;
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/* Strings saying where the definition came from. */
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const char *what;
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const char *where;
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/* Basename for this search path element. The string must end with
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a slash character. */
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const char *dirname;
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size_t dirnamelen;
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enum r_dir_status status[0];
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};
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struct r_strlenpair
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{
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const char *str;
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size_t len;
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};
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/* A data structure for a simple single linked list of strings. */
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struct libname_list
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{
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const char *name; /* Name requested (before search). */
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struct libname_list *next; /* Link to next name for this object. */
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};
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/* Test whether given NAME matches any of the names of the given object. */
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static __inline int
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__attribute__ ((unused))
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_dl_name_match_p (const char *__name, struct link_map *__map)
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{
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int __found = strcmp (__name, __map->l_name) == 0;
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struct libname_list *__runp = __map->l_libname;
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while (! __found && __runp != NULL)
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if (strcmp (__name, __runp->name) == 0)
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__found = 1;
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else
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__runp = __runp->next;
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return __found;
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}
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/* Function used as argument for `_dl_receive_error' function. The
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arguments are the error code, error string, and the objname the
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error occurred in. */
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typedef void (*receiver_fct) (int, const char *, const char *);
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/* Internal functions of the run-time dynamic linker.
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These can be accessed if you link again the dynamic linker
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as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
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but are not normally of interest to user programs.
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The `-ldl' library functions in <dlfcn.h> provide a simple
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user interface to run-time dynamic linking. */
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/* Parameters passed to the dynamic linker. */
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extern char **_dl_argv;
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/* Cached value of `getpagesize ()'. */
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extern size_t _dl_pagesize;
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/* File descriptor referring to the zero-fill device. */
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extern int _dl_zerofd;
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/* Name of the shared object to be profiled (if any). */
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extern const char *_dl_profile;
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/* Map of shared object to be profiled. */
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extern struct link_map *_dl_profile_map;
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/* Filename of the output file. */
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extern const char *_dl_profile_output;
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/* If nonzero the appropriate debug information is printed. */
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extern int _dl_debug_libs;
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extern int _dl_debug_impcalls;
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extern int _dl_debug_bindings;
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extern int _dl_debug_symbols;
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extern int _dl_debug_versions;
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extern int _dl_debug_reloc;
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extern int _dl_debug_files;
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/* Expect cache ID. */
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extern int _dl_correct_cache_id;
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/* Mask for hardware capabilities that are available. */
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extern unsigned long int _dl_hwcap;
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/* Mask for important hardware capabilities we honour. */
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extern unsigned long int _dl_hwcap_mask;
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/* File deccriptor to write debug messages to. */
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extern int _dl_debug_fd;
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/* Names of shared object for which the RPATH should be ignored. */
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extern const char *_dl_inhibit_rpath;
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/* OS-dependent function to open the zero-fill device. */
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extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
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/* OS-dependent function to write a message on the specified
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descriptor FD. All arguments are `const char *'; args until a null
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pointer are concatenated to form the message to print. */
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extern void _dl_sysdep_output (int fd, const char *string, ...);
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/* OS-dependent function to write a debug message on the specified
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descriptor for this. All arguments are `const char *'; args until
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a null pointer are concatenated to form the message to print. If
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NEW_LINE is nonzero it is assumed that the message starts on a new
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line.*/
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extern void _dl_debug_message (int new_line, const char *string, ...);
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/* OS-dependent function to write a message on the standard output.
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All arguments are `const char *'; args until a null pointer
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are concatenated to form the message to print. */
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#define _dl_sysdep_message(string, args...) \
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_dl_sysdep_output (STDOUT_FILENO, string, ##args)
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/* OS-dependent function to write a message on the standard error.
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All arguments are `const char *'; args until a null pointer
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are concatenated to form the message to print. */
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#define _dl_sysdep_error(string, args...) \
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_dl_sysdep_output (STDERR_FILENO, string, ##args)
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/* OS-dependent function to give a fatal error message and exit
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when the dynamic linker fails before the program is fully linked.
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All arguments are `const char *'; args until a null pointer
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are concatenated to form the message to print. */
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#define _dl_sysdep_fatal(string, args...) \
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do \
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{ \
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_dl_sysdep_output (STDERR_FILENO, string, ##args); \
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_exit (127); \
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} \
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while (1)
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/* Nonzero if the program should be "secure" (i.e. it's setuid or somesuch).
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This tells the dynamic linker to ignore environment variables. */
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extern int _dl_secure;
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/* This function is called by all the internal dynamic linker functions
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when they encounter an error. ERRCODE is either an `errno' code or
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zero; OBJECT is the name of the problematical shared object, or null if
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it is a general problem; ERRSTRING is a string describing the specific
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problem. */
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extern void _dl_signal_error (int errcode,
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const char *object,
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const char *errstring)
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internal_function;
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/* Call OPERATE, catching errors from `dl_signal_error'. If there is no
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error, *ERRSTRING is set to null. If there is an error, *ERRSTRING is
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set to a string constructed from the strings passed to _dl_signal_error,
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and the error code passed is the return value. ERRSTRING if nonzero
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points to a malloc'ed string which the caller has to free after use.
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ARGS is passed as argument to OPERATE. */
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extern int _dl_catch_error (char **errstring,
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void (*operate) (void *),
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void *args)
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internal_function;
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/* Call OPERATE, receiving errors from `dl_signal_error'. Unlike
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`_dl_catch_error' the operation is resumed after the OPERATE
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function returns.
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ARGS is passed as argument to OPERATE. */
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extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
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void *args)
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internal_function;
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/* Helper function for <dlfcn.h> functions. Runs the OPERATE function via
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_dl_catch_error. Returns zero for success, nonzero for failure; and
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arranges for `dlerror' to return the error details.
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ARGS is passed as argument to OPERATE. */
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extern int _dlerror_run (void (*operate) (void *), void *args)
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internal_function;
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/* Open the shared object NAME and map in its segments.
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LOADER's DT_RPATH is used in searching for NAME.
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If the object is already opened, returns its existing map.
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For preloaded shared objects PRELOADED is set to a non-zero
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value to allow additional security checks. */
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extern struct link_map *_dl_map_object (struct link_map *loader,
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const char *name, int preloaded,
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int type, int trace_mode)
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internal_function;
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/* Call _dl_map_object on the dependencies of MAP, and set up
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MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
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loaded objects that will be inserted into MAP->l_searchlist after MAP
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but before its dependencies. */
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extern void _dl_map_object_deps (struct link_map *map,
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struct link_map **preloads,
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unsigned int npreloads, int trace_mode)
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internal_function;
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/* Cache the locations of MAP's hash table. */
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extern void _dl_setup_hash (struct link_map *map) internal_function;
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/* Open the shared object NAME, relocate it, and run its initializer if it
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hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
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the object is already opened, returns its existing map. */
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extern struct link_map *_dl_open (const char *name, int mode)
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internal_function;
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/* Close an object previously opened by _dl_open. */
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extern void _dl_close (struct link_map *map)
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internal_function;
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/* Search loaded objects' symbol tables for a definition of the symbol
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referred to by UNDEF. *SYM is the symbol table entry containing the
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reference; it is replaced with the defining symbol, and the base load
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address of the defining object is returned. SYMBOL_SCOPE is a
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null-terminated list of object scopes to search; each object's
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l_searchlist (i.e. the segment of the dependency tree starting at that
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object) is searched in turn. REFERENCE_NAME should name the object
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containing the reference; it is used in error messages.
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RELOC_TYPE is a machine-dependent reloc type, which is passed to
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the `elf_machine_lookup_*_p' macros in dl-machine.h to affect which
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symbols can be chosen. */
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extern ElfW(Addr) _dl_lookup_symbol (const char *undef,
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const ElfW(Sym) **sym,
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struct link_map *symbol_scope[],
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const char *reference_name,
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int reloc_type)
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internal_function;
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/* Lookup versioned symbol. */
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extern ElfW(Addr) _dl_lookup_versioned_symbol (const char *undef,
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const ElfW(Sym) **sym,
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struct link_map *symbol_scope[],
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const char *reference_name,
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const struct r_found_version *version,
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int reloc_type)
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internal_function;
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/* For handling RTLD_NEXT we must be able to skip shared objects. */
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extern ElfW(Addr) _dl_lookup_symbol_skip (const char *undef,
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const ElfW(Sym) **sym,
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struct link_map *symbol_scope[],
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const char *reference_name,
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struct link_map *skip_this)
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internal_function;
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/* For handling RTLD_NEXT with versioned symbols we must be able to
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skip shared objects. */
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extern ElfW(Addr) _dl_lookup_versioned_symbol_skip (const char *undef,
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const ElfW(Sym) **sym,
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struct link_map *symbol_scope[],
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const char *reference_name,
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const struct r_found_version *version,
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struct link_map *skip_this)
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internal_function;
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/* Locate shared object containing the given address. */
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extern int _dl_addr (const void *address, Dl_info *info)
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internal_function;
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/* Look up symbol NAME in MAP's scope and return its run-time address. */
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extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name)
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internal_function;
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/* Structure describing the dynamic linker itself. */
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extern struct link_map _dl_rtld_map;
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/* The list of objects currently loaded is the third element of the
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`_dl_default_scope' array, and the fourth element is always null.
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This leaves two slots before it that are used when resolving
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DT_SYMBOLIC objects' references one after it for normal references
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(see below). */
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#define _dl_loaded (_dl_default_scope[2])
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extern struct link_map *_dl_default_scope[5];
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/* Null-terminated list of objects in the dynamic `global scope'. The
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list starts at [2]; i.e. &_dl_global_scope[2] is the argument
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passed to _dl_lookup_symbol to search the global scope. To search
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a specific object and its dependencies in preference to the global
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scope, fill in the [1] slot and pass its address; for two specific
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object scopes, fill [0] and [1]. The list is double-terminated; to
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search the global scope and then a specific object and its
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dependencies, set *_dl_global_scope_end. This variable initially
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points to _dl_default_scope, and _dl_loaded is always kept in [2]
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of this list. A new list is malloc'd when new objects are loaded
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with RTLD_GLOBAL. */
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extern struct link_map **_dl_global_scope, **_dl_global_scope_end;
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extern size_t _dl_global_scope_alloc; /* Number of slots malloc'd. */
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/* Hack _dl_global_scope[0] and [1] as necessary, and return a pointer into
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_dl_global_scope that should be passed to _dl_lookup_symbol for symbol
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references made in the object MAP's relocations. */
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extern struct link_map **_dl_object_relocation_scope (struct link_map *map)
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internal_function;
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/* Allocate a `struct link_map' for a new object being loaded,
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and enter it into the _dl_loaded list. */
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extern struct link_map *_dl_new_object (char *realname, const char *libname,
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int type) internal_function;
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/* Relocate the given object (if it hasn't already been).
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SCOPE is passed to _dl_lookup_symbol in symbol lookups.
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If LAZY is nonzero, don't relocate its PLT. */
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extern void _dl_relocate_object (struct link_map *map,
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struct link_map *scope[],
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int lazy, int consider_profiling);
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/* Check the version dependencies of all objects available through
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MAP. If VERBOSE print some more diagnostics. */
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extern int _dl_check_all_versions (struct link_map *map, int verbose)
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internal_function;
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/* Check the version dependencies for MAP. If VERBOSE print some more
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diagnostics. */
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extern int _dl_check_map_versions (struct link_map *map, int verbose)
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internal_function;
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/* Return the address of the next initializer function for MAP or one of
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its dependencies that has not yet been run. When there are no more
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initializers to be run, this returns zero. The functions are returned
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in the order they should be called. */
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extern ElfW(Addr) _dl_init_next (struct link_map *map) internal_function;
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/* Call the finalizer functions of all shared objects whose
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initializer functions have completed. */
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extern void _dl_fini (void) internal_function;
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/* The dynamic linker calls this function before and having changing
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any shared object mappings. The `r_state' member of `struct r_debug'
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says what change is taking place. This function's address is
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the value of the `r_brk' member. */
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extern void _dl_debug_state (void);
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/* Initialize `struct r_debug' if it has not already been done. The
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argument is the run-time load address of the dynamic linker, to be put
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in the `r_ldbase' member. Returns the address of the structure. */
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extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase)
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internal_function;
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/* Initialize the basic data structure for the search paths. */
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extern void _dl_init_paths (const char *library_path) internal_function;
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/* Gather the information needed to install the profiling tables and start
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the timers. */
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extern void _dl_start_profile (struct link_map *map, const char *output_dir)
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internal_function;
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/* The actual functions used to keep book on the calls. */
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extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
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/* This function is simply a wrapper around the _dl_mcount function
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which does not require a FROMPC parameter since this is the
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calling function. */
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extern void _dl_mcount_wrapper (ElfW(Addr) selfpc);
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/* Show the members of the auxiliary array passed up from the kernel. */
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extern void _dl_show_auxv (void) internal_function;
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/* Return all environment variables starting with `LD_', one after the
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other. */
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extern char *_dl_next_ld_env_entry (char ***position) internal_function;
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/* Return an array with the names of the important hardware capabilities. */
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extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
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size_t paltform_len,
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size_t *sz,
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size_t *max_capstrlen)
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internal_function;
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/* When we do profiling we have the problem that uses of `dlopen'ed
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objects don't use the PLT but instead use a pointer to the function.
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We still want to have profiling data and in these cases we must do
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the work of calling `_dl_mcount' ourself. The following macros
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helps do it. */
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#define _CALL_DL_FCT(fctp, args) \
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({ if (_dl_profile_map != NULL) \
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_dl_mcount_wrapper ((ElfW(Addr)) fctp); \
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(*fctp) args; \
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})
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__END_DECLS
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#endif /* ldsodefs.h */
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