1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
|
/* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
Copyright (C) 1996-2002, 2003, 2004 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <assert.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <sys/mman.h>
#include <dl-cache.h>
#include <dl-procinfo.h>
#include <stdio-common/_itoa.h>
#ifndef _DL_PLATFORMS_COUNT
# define _DL_PLATFORMS_COUNT 0
#endif
/* This is the starting address and the size of the mmap()ed file. */
static struct cache_file *cache;
static struct cache_file_new *cache_new;
static size_t cachesize;
/* 1 if cache_data + PTR points into the cache. */
#define _dl_cache_verify_ptr(ptr) (ptr < cache_data_size)
#define SEARCH_CACHE(cache) \
/* We use binary search since the table is sorted in the cache file. \
The first matching entry in the table is returned. \
It is important to use the same algorithm as used while generating \
the cache file. */ \
do \
{ \
left = 0; \
right = cache->nlibs - 1; \
\
while (left <= right) \
{ \
__typeof__ (cache->libs[0].key) key; \
\
middle = (left + right) / 2; \
\
key = cache->libs[middle].key; \
\
/* Make sure string table indices are not bogus before using \
them. */ \
if (! _dl_cache_verify_ptr (key)) \
{ \
cmpres = 1; \
break; \
} \
\
/* Actually compare the entry with the key. */ \
cmpres = _dl_cache_libcmp (name, cache_data + key); \
if (__builtin_expect (cmpres == 0, 0)) \
{ \
/* Found it. LEFT now marks the last entry for which we \
know the name is correct. */ \
left = middle; \
\
/* There might be entries with this name before the one we \
found. So we have to find the beginning. */ \
while (middle > 0) \
{ \
__typeof__ (cache->libs[0].key) key; \
\
key = cache->libs[middle - 1].key; \
/* Make sure string table indices are not bogus before \
using them. */ \
if (! _dl_cache_verify_ptr (key) \
/* Actually compare the entry. */ \
|| _dl_cache_libcmp (name, cache_data + key) != 0) \
break; \
--middle; \
} \
\
do \
{ \
int flags; \
__typeof__ (cache->libs[0]) *lib = &cache->libs[middle]; \
\
/* Only perform the name test if necessary. */ \
if (middle > left \
/* We haven't seen this string so far. Test whether the \
index is ok and whether the name matches. Otherwise \
we are done. */ \
&& (! _dl_cache_verify_ptr (lib->key) \
|| (_dl_cache_libcmp (name, cache_data + lib->key) \
!= 0))) \
break; \
\
flags = lib->flags; \
if (_dl_cache_check_flags (flags) \
&& _dl_cache_verify_ptr (lib->value)) \
{ \
if (best == NULL || flags == GLRO(dl_correct_cache_id)) \
{ \
HWCAP_CHECK; \
best = cache_data + lib->value; \
\
if (flags == GLRO(dl_correct_cache_id)) \
/* We've found an exact match for the shared \
object and no general `ELF' release. Stop \
searching. */ \
break; \
} \
} \
} \
while (++middle <= right); \
break; \
} \
\
if (cmpres < 0) \
left = middle + 1; \
else \
right = middle - 1; \
} \
} \
while (0)
int
internal_function
_dl_cache_libcmp (const char *p1, const char *p2)
{
while (*p1 != '\0')
{
if (*p1 >= '0' && *p1 <= '9')
{
if (*p2 >= '0' && *p2 <= '9')
{
/* Must compare this numerically. */
int val1;
int val2;
val1 = *p1++ - '0';
val2 = *p2++ - '0';
while (*p1 >= '0' && *p1 <= '9')
val1 = val1 * 10 + *p1++ - '0';
while (*p2 >= '0' && *p2 <= '9')
val2 = val2 * 10 + *p2++ - '0';
if (val1 != val2)
return val1 - val2;
}
else
return 1;
}
else if (*p2 >= '0' && *p2 <= '9')
return -1;
else if (*p1 != *p2)
return *p1 - *p2;
else
{
++p1;
++p2;
}
}
return *p1 - *p2;
}
/* Look up NAME in ld.so.cache and return the file name stored there,
or null if none is found. */
const char *
internal_function
_dl_load_cache_lookup (const char *name)
{
int left, right, middle;
int cmpres;
const char *cache_data;
uint32_t cache_data_size;
const char *best;
/* Print a message if the loading of libs is traced. */
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0))
_dl_debug_printf (" search cache=%s\n", LD_SO_CACHE);
if (cache == NULL)
{
/* Read the contents of the file. */
void *file = _dl_sysdep_read_whole_file (LD_SO_CACHE, &cachesize,
PROT_READ);
/* We can handle three different cache file formats here:
- the old libc5/glibc2.0/2.1 format
- the old format with the new format in it
- only the new format
The following checks if the cache contains any of these formats. */
if (file != MAP_FAILED && cachesize > sizeof *cache
&& memcmp (file, CACHEMAGIC, sizeof CACHEMAGIC - 1) == 0)
{
size_t offset;
/* Looks ok. */
cache = file;
/* Check for new version. */
offset = ALIGN_CACHE (sizeof (struct cache_file)
+ cache->nlibs * sizeof (struct file_entry));
cache_new = (struct cache_file_new *) ((void *) cache + offset);
if (cachesize < (offset + sizeof (struct cache_file_new))
|| memcmp (cache_new->magic, CACHEMAGIC_VERSION_NEW,
sizeof CACHEMAGIC_VERSION_NEW - 1) != 0)
cache_new = (void *) -1;
}
else if (file != MAP_FAILED && cachesize > sizeof *cache_new
&& memcmp (file, CACHEMAGIC_VERSION_NEW,
sizeof CACHEMAGIC_VERSION_NEW - 1) == 0)
{
cache_new = file;
cache = file;
}
else
{
if (file != MAP_FAILED)
__munmap (file, cachesize);
cache = (void *) -1;
}
assert (cache != NULL);
}
if (cache == (void *) -1)
/* Previously looked for the cache file and didn't find it. */
return NULL;
best = NULL;
if (cache_new != (void *) -1)
{
/* This file ends in static libraries where we don't have a hwcap. */
unsigned long int *hwcap;
uint64_t platform;
#ifndef SHARED
weak_extern (_dl_hwcap);
#endif
/* This is where the strings start. */
cache_data = (const char *) cache_new;
/* Now we can compute how large the string table is. */
cache_data_size = (const char *) cache + cachesize - cache_data;
hwcap = &GLRO(dl_hwcap);
platform = _dl_string_platform (GLRO(dl_platform));
if (platform != (uint64_t) -1)
platform = 1ULL << platform;
/* Only accept hwcap if it's for the right platform. */
#define HWCAP_CHECK \
if (GLRO(dl_osversion) \
&& cache_new->libs[middle].osversion > GLRO(dl_osversion)) \
continue; \
if (_DL_PLATFORMS_COUNT && platform != -1 \
&& (lib->hwcap & _DL_HWCAP_PLATFORM) != 0 \
&& (lib->hwcap & _DL_HWCAP_PLATFORM) != platform) \
continue; \
if (hwcap \
&& ((lib->hwcap & *hwcap & ~_DL_HWCAP_PLATFORM) > *hwcap)) \
continue
SEARCH_CACHE (cache_new);
}
else
{
/* This is where the strings start. */
cache_data = (const char *) &cache->libs[cache->nlibs];
/* Now we can compute how large the string table is. */
cache_data_size = (const char *) cache + cachesize - cache_data;
#undef HWCAP_CHECK
#define HWCAP_CHECK do {} while (0)
SEARCH_CACHE (cache);
}
/* Print our result if wanted. */
if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0)
&& best != NULL)
_dl_debug_printf (" trying file=%s\n", best);
return best;
}
#ifndef MAP_COPY
/* If the system does not support MAP_COPY we cannot leave the file open
all the time since this would create problems when the file is replaced.
Therefore we provide this function to close the file and open it again
once needed. */
void
_dl_unload_cache (void)
{
if (cache != NULL && cache != (struct cache_file *) -1)
{
__munmap (cache, cachesize);
cache = NULL;
}
}
#endif
|
