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/* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
Copyright (C) 1996 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., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <link.h>
#include <stddef.h>
#include <sys/mman.h>
/* System-dependent function to read a file's whole contents
in the most convenient manner available. */
extern void *_dl_sysdep_read_whole_file (const char *filename,
size_t *filesize_ptr,
int mmap_prot);
#define CACHEMAGIC "ld.so-1.7.0"
struct cache_file
{
char magic[sizeof CACHEMAGIC - 1];
unsigned int nlibs;
struct
{
int flags; /* This is 1 for an ELF library. */
unsigned int key, value; /* String table indices. */
} libs[0];
};
/* Look up NAME in ld.so.cache and return the file name stored there,
or null if none is found. */
const char *
_dl_load_cache_lookup (const char *name)
{
static struct cache_file *cache;
static size_t cachesize;
unsigned int i;
if (cache == (void *) -1)
/* Previously looked for the cache file and didn't find it. */
return NULL;
if (cache == NULL)
{
/* Read the contents of the file. */
void *file = _dl_sysdep_read_whole_file ("/etc/ld.so.cache", &cachesize,
PROT_READ);
if (file && cachesize > sizeof *cache &&
!memcmp (file, CACHEMAGIC, sizeof CACHEMAGIC - 1))
/* Looks ok. */
cache = file;
else
{
if (file)
__munmap (file, cachesize);
cache = (void *) -1;
return NULL;
}
}
for (i = 0; i < cache->nlibs; ++i)
if (cache->libs[i].flags == 1 && /* ELF library entry. */
/* Make sure string table indices are not bogus before using them. */
cache->libs[i].key < cachesize - sizeof *cache &&
cache->libs[i].value < cachesize - sizeof *cache &&
/* Does the name match? */
! strcmp (name, ((const char *) &cache->libs[cache->nlibs] +
cache->libs[i].key)))
return (const char *) &cache->libs[cache->nlibs] + cache->libs[i].value;
return NULL;
}
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