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authorRoland McGrath <roland@gnu.org>1996-07-17 23:09:43 +0000
committerRoland McGrath <roland@gnu.org>1996-07-17 23:09:43 +0000
commitf18edac3a387b956579f7a5ed0e46322c83432b2 (patch)
tree354b64ed298f71755f403674dfc0e7d8dd5abaf0 /elf
parent3867ee645cc03dba836667728d60cabbae111255 (diff)
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Wed Jul 17 21:53:45 1996 Roland McGrath <roland@delasyd.gnu.ai.mit.edu>
* elf/Makefile (dl-routines): Add dl-cache. * elf/dl-cache.c: New file. * elf/dl-load.c (_dl_map_object): Check cache before default path.
Diffstat (limited to 'elf')
-rw-r--r--elf/Makefile2
-rw-r--r--elf/dl-cache.c85
-rw-r--r--elf/dl-load.c23
3 files changed, 109 insertions, 1 deletions
diff --git a/elf/Makefile b/elf/Makefile
index 13fced3..3b3bd14 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -25,7 +25,7 @@ routines = $(dl-routines) dl-open dl-close dl-symbol dl-support
# The core dynamic linking functions are in libc for the static and
# profiled libraries.
-dl-routines = $(addprefix dl-,load lookup object reloc deps \
+dl-routines = $(addprefix dl-,load cache lookup object reloc deps \
runtime error init fini debug)
# But they are absent from the shared libc, because that code is in ld.so.
elide-routines.so = $(dl-routines) dl-support
diff --git a/elf/dl-cache.c b/elf/dl-cache.c
new file mode 100644
index 0000000..a282d31
--- /dev/null
+++ b/elf/dl-cache.c
@@ -0,0 +1,85 @@
+/* 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 <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;
+}
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 29ac0bf..fc27332 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -513,6 +513,29 @@ _dl_map_object (struct link_map *loader, const char *name, int type)
/* Try an environment variable (unless setuid). */
if (fd == -1 && ! _dl_secure)
trypath (getenv ("LD_LIBRARY_PATH"));
+ if (fd == -1)
+ {
+ /* Check the list of libraries in the file /etc/ld.so.cache,
+ for compatibility with Linux's ldconfig program. */
+ extern const char *_dl_load_cache_lookup (const char *name);
+ const char *cached = _dl_load_cache_lookup (name);
+ if (cached)
+ {
+ fd = __open (cached, O_RDONLY);
+ if (fd != -1)
+ {
+ size_t cl = strlen (cached) + 1;
+ realname = malloc (cl);
+ if (realname)
+ memcpy (realname, cached, cl);
+ else
+ {
+ __close (fd);
+ fd = -1;
+ }
+ }
+ }
+ }
/* Finally, try the default path. */
if (fd == -1)
{