101 lines
3.0 KiB
C
101 lines
3.0 KiB
C
/* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
|
|
Copyright (C) 1996, 1997 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. */
|
|
|
|
#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);
|
|
|
|
#ifndef LD_SO_CACHE
|
|
# define LD_SO_CACHE "/etc/ld.so.cache"
|
|
#endif
|
|
|
|
#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;
|
|
const char *best;
|
|
|
|
if (cache == NULL)
|
|
{
|
|
/* Read the contents of the file. */
|
|
void *file = _dl_sysdep_read_whole_file (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;
|
|
}
|
|
}
|
|
|
|
if (cache == (void *) -1)
|
|
/* Previously looked for the cache file and didn't find it. */
|
|
return NULL;
|
|
|
|
best = NULL;
|
|
for (i = 0; i < cache->nlibs; ++i)
|
|
if ((cache->libs[i].flags == 1 ||
|
|
cache->libs[i].flags == 3) && /* 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)))
|
|
{
|
|
best = ((const char *) &cache->libs[cache->nlibs]
|
|
+ cache->libs[i].value);
|
|
|
|
if (cache->libs[i].flags == 3)
|
|
/* We've found an exact match for the shared object and no
|
|
general `ELF' release. Stop searching. */
|
|
break;
|
|
}
|
|
return best;
|
|
}
|