aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/generic/dl-cache.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/generic/dl-cache.c')
-rw-r--r--sysdeps/generic/dl-cache.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/sysdeps/generic/dl-cache.c b/sysdeps/generic/dl-cache.c
new file mode 100644
index 0000000000..6cd454c7ac
--- /dev/null
+++ b/sysdeps/generic/dl-cache.c
@@ -0,0 +1,86 @@
+/* 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;
+}