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