| 1 |
207 |
jeremybenn |
/* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
|
| 2 |
|
|
Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
|
| 3 |
|
|
This file is part of the GNU C Library.
|
| 4 |
|
|
|
| 5 |
|
|
The GNU C Library is free software; you can redistribute it and/or
|
| 6 |
|
|
modify it under the terms of the GNU Lesser General Public
|
| 7 |
|
|
License as published by the Free Software Foundation; either
|
| 8 |
|
|
version 2.1 of the License, or (at your option) any later version.
|
| 9 |
|
|
|
| 10 |
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
| 11 |
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
| 12 |
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
| 13 |
|
|
Lesser General Public License for more details.
|
| 14 |
|
|
|
| 15 |
|
|
You should have received a copy of the GNU Lesser General Public
|
| 16 |
|
|
License along with the GNU C Library; if not, write to the Free
|
| 17 |
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
| 18 |
|
|
02111-1307 USA. */
|
| 19 |
|
|
|
| 20 |
|
|
#include <assert.h>
|
| 21 |
|
|
#include <unistd.h>
|
| 22 |
|
|
#include <ldsodefs.h>
|
| 23 |
|
|
#include <sys/mman.h>
|
| 24 |
|
|
#include <dl-cache.h>
|
| 25 |
|
|
#include <machine/dl-procinfo.h>
|
| 26 |
|
|
#include <machine/weakalias.h>
|
| 27 |
|
|
|
| 28 |
|
|
extern const char *_dl_platform;
|
| 29 |
|
|
|
| 30 |
|
|
#ifndef _DL_PLATFORMS_COUNT
|
| 31 |
|
|
# define _DL_PLATFORMS_COUNT 0
|
| 32 |
|
|
#endif
|
| 33 |
|
|
|
| 34 |
|
|
/* This is the starting address and the size of the mmap()ed file. */
|
| 35 |
|
|
static struct cache_file *cache;
|
| 36 |
|
|
static struct cache_file_new *cache_new;
|
| 37 |
|
|
static size_t cachesize;
|
| 38 |
|
|
|
| 39 |
|
|
/* 1 if cache_data + PTR points into the cache. */
|
| 40 |
|
|
#define _dl_cache_verify_ptr(ptr) (ptr < cache_data_size)
|
| 41 |
|
|
|
| 42 |
|
|
/* This is the cache ID we expect. Normally it is 3 for glibc linked
|
| 43 |
|
|
binaries. */
|
| 44 |
|
|
int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID;
|
| 45 |
|
|
|
| 46 |
|
|
#define SEARCH_CACHE(cache) \
|
| 47 |
|
|
/* We use binary search since the table is sorted in the cache file. \
|
| 48 |
|
|
The first matching entry in the table is returned. \
|
| 49 |
|
|
It is important to use the same algorithm as used while generating \
|
| 50 |
|
|
the cache file. */ \
|
| 51 |
|
|
do \
|
| 52 |
|
|
{ \
|
| 53 |
|
|
left = 0; \
|
| 54 |
|
|
right = cache->nlibs - 1; \
|
| 55 |
|
|
\
|
| 56 |
|
|
while (left <= right) \
|
| 57 |
|
|
{ \
|
| 58 |
|
|
__typeof__ (cache->libs[0].key) key; \
|
| 59 |
|
|
\
|
| 60 |
|
|
middle = (left + right) / 2; \
|
| 61 |
|
|
\
|
| 62 |
|
|
key = cache->libs[middle].key; \
|
| 63 |
|
|
\
|
| 64 |
|
|
/* Make sure string table indices are not bogus before using \
|
| 65 |
|
|
them. */ \
|
| 66 |
|
|
if (! _dl_cache_verify_ptr (key)) \
|
| 67 |
|
|
{ \
|
| 68 |
|
|
cmpres = 1; \
|
| 69 |
|
|
break; \
|
| 70 |
|
|
} \
|
| 71 |
|
|
\
|
| 72 |
|
|
/* Actually compare the entry with the key. */ \
|
| 73 |
|
|
cmpres = _dl_cache_libcmp (name, cache_data + key); \
|
| 74 |
|
|
if (__builtin_expect (cmpres == 0, 0)) \
|
| 75 |
|
|
{ \
|
| 76 |
|
|
/* Found it. LEFT now marks the last entry for which we \
|
| 77 |
|
|
know the name is correct. */ \
|
| 78 |
|
|
left = middle; \
|
| 79 |
|
|
\
|
| 80 |
|
|
/* There might be entries with this name before the one we \
|
| 81 |
|
|
found. So we have to find the beginning. */ \
|
| 82 |
|
|
while (middle > 0) \
|
| 83 |
|
|
{ \
|
| 84 |
|
|
__typeof__ (cache->libs[0].key) key; \
|
| 85 |
|
|
\
|
| 86 |
|
|
key = cache->libs[middle - 1].key; \
|
| 87 |
|
|
/* Make sure string table indices are not bogus before \
|
| 88 |
|
|
using them. */ \
|
| 89 |
|
|
if (! _dl_cache_verify_ptr (key) \
|
| 90 |
|
|
/* Actually compare the entry. */ \
|
| 91 |
|
|
|| _dl_cache_libcmp (name, cache_data + key) != 0) \
|
| 92 |
|
|
break; \
|
| 93 |
|
|
--middle; \
|
| 94 |
|
|
} \
|
| 95 |
|
|
\
|
| 96 |
|
|
do \
|
| 97 |
|
|
{ \
|
| 98 |
|
|
int flags; \
|
| 99 |
|
|
__typeof__ (cache->libs[0]) *lib = &cache->libs[middle]; \
|
| 100 |
|
|
\
|
| 101 |
|
|
/* Only perform the name test if necessary. */ \
|
| 102 |
|
|
if (middle > left \
|
| 103 |
|
|
/* We haven't seen this string so far. Test whether the \
|
| 104 |
|
|
index is ok and whether the name matches. Otherwise \
|
| 105 |
|
|
we are done. */ \
|
| 106 |
|
|
&& (! _dl_cache_verify_ptr (lib->key) \
|
| 107 |
|
|
|| (_dl_cache_libcmp (name, cache_data + lib->key) \
|
| 108 |
|
|
!= 0))) \
|
| 109 |
|
|
break; \
|
| 110 |
|
|
\
|
| 111 |
|
|
flags = lib->flags; \
|
| 112 |
|
|
if (_dl_cache_check_flags (flags) \
|
| 113 |
|
|
&& _dl_cache_verify_ptr (lib->value)) \
|
| 114 |
|
|
{ \
|
| 115 |
|
|
if (best == NULL || flags == _dl_correct_cache_id) \
|
| 116 |
|
|
{ \
|
| 117 |
|
|
HWCAP_CHECK; \
|
| 118 |
|
|
best = cache_data + lib->value; \
|
| 119 |
|
|
\
|
| 120 |
|
|
if (flags == _dl_correct_cache_id) \
|
| 121 |
|
|
/* We've found an exact match for the shared \
|
| 122 |
|
|
object and no general `ELF' release. Stop \
|
| 123 |
|
|
searching. */ \
|
| 124 |
|
|
break; \
|
| 125 |
|
|
} \
|
| 126 |
|
|
} \
|
| 127 |
|
|
} \
|
| 128 |
|
|
while (++middle <= right); \
|
| 129 |
|
|
break; \
|
| 130 |
|
|
} \
|
| 131 |
|
|
\
|
| 132 |
|
|
if (cmpres < 0) \
|
| 133 |
|
|
left = middle + 1; \
|
| 134 |
|
|
else \
|
| 135 |
|
|
right = middle - 1; \
|
| 136 |
|
|
} \
|
| 137 |
|
|
} \
|
| 138 |
|
|
while (0)
|
| 139 |
|
|
|
| 140 |
|
|
|
| 141 |
|
|
|
| 142 |
|
|
/* Look up NAME in ld.so.cache and return the file name stored there,
|
| 143 |
|
|
or null if none is found. */
|
| 144 |
|
|
|
| 145 |
|
|
const char *
|
| 146 |
|
|
internal_function
|
| 147 |
|
|
_dl_load_cache_lookup (const char *name)
|
| 148 |
|
|
{
|
| 149 |
|
|
int left, right, middle;
|
| 150 |
|
|
int cmpres;
|
| 151 |
|
|
const char *cache_data;
|
| 152 |
|
|
uint32_t cache_data_size;
|
| 153 |
|
|
const char *best;
|
| 154 |
|
|
|
| 155 |
|
|
if (cache == NULL)
|
| 156 |
|
|
{
|
| 157 |
|
|
/* Read the contents of the file. */
|
| 158 |
|
|
void *file = _dl_sysdep_read_whole_file (LD_SO_CACHE, &cachesize,
|
| 159 |
|
|
PROT_READ);
|
| 160 |
|
|
|
| 161 |
|
|
/* We can handle three different cache file formats here:
|
| 162 |
|
|
- the old libc5/glibc2.0/2.1 format
|
| 163 |
|
|
- the old format with the new format in it
|
| 164 |
|
|
- only the new format
|
| 165 |
|
|
The following checks if the cache contains any of these formats. */
|
| 166 |
|
|
if (file != MAP_FAILED && cachesize > sizeof *cache
|
| 167 |
|
|
&& memcmp (file, CACHEMAGIC, sizeof CACHEMAGIC - 1) == 0)
|
| 168 |
|
|
{
|
| 169 |
|
|
size_t offset;
|
| 170 |
|
|
/* Looks ok. */
|
| 171 |
|
|
cache = file;
|
| 172 |
|
|
|
| 173 |
|
|
/* Check for new version. */
|
| 174 |
|
|
offset = ALIGN_CACHE (sizeof (struct cache_file)
|
| 175 |
|
|
+ cache->nlibs * sizeof (struct file_entry));
|
| 176 |
|
|
|
| 177 |
|
|
cache_new = (struct cache_file_new *) ((void *) cache + offset);
|
| 178 |
|
|
if (cachesize < (offset + sizeof (struct cache_file_new))
|
| 179 |
|
|
|| memcmp (cache_new->magic, CACHEMAGIC_VERSION_NEW,
|
| 180 |
|
|
sizeof CACHEMAGIC_VERSION_NEW - 1) != 0)
|
| 181 |
|
|
cache_new = (void *) -1;
|
| 182 |
|
|
}
|
| 183 |
|
|
else if (file != MAP_FAILED && cachesize > sizeof *cache_new
|
| 184 |
|
|
&& memcmp (file, CACHEMAGIC_VERSION_NEW,
|
| 185 |
|
|
sizeof CACHEMAGIC_VERSION_NEW - 1) == 0)
|
| 186 |
|
|
{
|
| 187 |
|
|
cache_new = file;
|
| 188 |
|
|
cache = file;
|
| 189 |
|
|
}
|
| 190 |
|
|
else
|
| 191 |
|
|
{
|
| 192 |
|
|
if (file != MAP_FAILED)
|
| 193 |
|
|
munmap (file, cachesize);
|
| 194 |
|
|
cache = (void *) -1;
|
| 195 |
|
|
}
|
| 196 |
|
|
|
| 197 |
|
|
assert (cache != NULL);
|
| 198 |
|
|
}
|
| 199 |
|
|
|
| 200 |
|
|
if (cache == (void *) -1)
|
| 201 |
|
|
/* Previously looked for the cache file and didn't find it. */
|
| 202 |
|
|
return NULL;
|
| 203 |
|
|
|
| 204 |
|
|
best = NULL;
|
| 205 |
|
|
|
| 206 |
|
|
if (cache_new != (void *) -1)
|
| 207 |
|
|
{
|
| 208 |
|
|
/* This file ends in static libraries where we don't have a hwcap. */
|
| 209 |
|
|
unsigned long int *hwcap;
|
| 210 |
|
|
uint64_t platform;
|
| 211 |
|
|
#pragma weak _dl_hwcap
|
| 212 |
|
|
|
| 213 |
|
|
/* This is where the strings start. */
|
| 214 |
|
|
cache_data = (const char *) cache_new;
|
| 215 |
|
|
|
| 216 |
|
|
/* Now we can compute how large the string table is. */
|
| 217 |
|
|
cache_data_size = (const char *) cache + cachesize - cache_data;
|
| 218 |
|
|
|
| 219 |
|
|
hwcap = &_dl_hwcap;
|
| 220 |
|
|
platform = _dl_string_platform (_dl_platform);
|
| 221 |
|
|
if (platform != -1)
|
| 222 |
|
|
platform = 1ULL << platform;
|
| 223 |
|
|
|
| 224 |
|
|
/* Only accept hwcap if it's for the right platform. */
|
| 225 |
|
|
#define HWCAP_CHECK \
|
| 226 |
|
|
if (_dl_osversion && cache_new->libs[middle].osversion > _dl_osversion) \
|
| 227 |
|
|
continue; \
|
| 228 |
|
|
if (_DL_PLATFORMS_COUNT && platform != -1 \
|
| 229 |
|
|
&& (lib->hwcap & _DL_HWCAP_PLATFORM) != 0 \
|
| 230 |
|
|
&& (lib->hwcap & _DL_HWCAP_PLATFORM) != platform) \
|
| 231 |
|
|
continue; \
|
| 232 |
|
|
if (hwcap \
|
| 233 |
|
|
&& ((lib->hwcap & *hwcap & ~_DL_HWCAP_PLATFORM) > *hwcap)) \
|
| 234 |
|
|
continue
|
| 235 |
|
|
SEARCH_CACHE (cache_new);
|
| 236 |
|
|
}
|
| 237 |
|
|
else
|
| 238 |
|
|
{
|
| 239 |
|
|
/* This is where the strings start. */
|
| 240 |
|
|
cache_data = (const char *) &cache->libs[cache->nlibs];
|
| 241 |
|
|
|
| 242 |
|
|
/* Now we can compute how large the string table is. */
|
| 243 |
|
|
cache_data_size = (const char *) cache + cachesize - cache_data;
|
| 244 |
|
|
|
| 245 |
|
|
#undef HWCAP_CHECK
|
| 246 |
|
|
#define HWCAP_CHECK do {} while (0)
|
| 247 |
|
|
SEARCH_CACHE (cache);
|
| 248 |
|
|
}
|
| 249 |
|
|
|
| 250 |
|
|
/* Print our result if wanted. */
|
| 251 |
|
|
if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0) && best != NULL)
|
| 252 |
|
|
_dl_debug_printf (" trying file=%s\n", best);
|
| 253 |
|
|
|
| 254 |
|
|
return best;
|
| 255 |
|
|
}
|
| 256 |
|
|
|
| 257 |
|
|
#ifndef MAP_COPY
|
| 258 |
|
|
/* If the system does not support MAP_COPY we cannot leave the file open
|
| 259 |
|
|
all the time since this would create problems when the file is replaced.
|
| 260 |
|
|
Therefore we provide this function to close the file and open it again
|
| 261 |
|
|
once needed. */
|
| 262 |
|
|
void
|
| 263 |
|
|
_dl_unload_cache (void)
|
| 264 |
|
|
{
|
| 265 |
|
|
if (cache != NULL && cache != (struct cache_file *) -1)
|
| 266 |
|
|
{
|
| 267 |
|
|
munmap (cache, cachesize);
|
| 268 |
|
|
cache = NULL;
|
| 269 |
|
|
}
|
| 270 |
|
|
}
|
| 271 |
|
|
#endif
|
