diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/Makefile | 2 | ||||
| -rw-r--r-- | elf/dl-cache.c | 85 | ||||
| -rw-r--r-- | elf/dl-load.c | 23 |
3 files changed, 109 insertions, 1 deletions
diff --git a/elf/Makefile b/elf/Makefile index 13fced3b85..3b3bd1457b 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 0000000000..a282d313cf --- /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 29ac0bfd87..fc2733252a 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) { |