Missing server address again leads to localhost being used
[glibc.git] / elf / dl-cache.c
blob5a01c2ed1d27664f153ca690debca1502c0668de
1 /* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
2 Copyright (C) 1996-2002,2003,2004,2006,2010
3 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
21 #include <assert.h>
22 #include <unistd.h>
23 #include <ldsodefs.h>
24 #include <sys/mman.h>
25 #include <dl-cache.h>
26 #include <dl-procinfo.h>
28 #include <stdio-common/_itoa.h>
30 #ifndef _DL_PLATFORMS_COUNT
31 # define _DL_PLATFORMS_COUNT 0
32 #endif
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;
39 /* 1 if cache_data + PTR points into the cache. */
40 #define _dl_cache_verify_ptr(ptr) (ptr < cache_data_size)
42 #define SEARCH_CACHE(cache) \
43 /* We use binary search since the table is sorted in the cache file. \
44 The first matching entry in the table is returned. \
45 It is important to use the same algorithm as used while generating \
46 the cache file. */ \
47 do \
48 { \
49 left = 0; \
50 right = cache->nlibs - 1; \
52 while (left <= right) \
53 { \
54 __typeof__ (cache->libs[0].key) key; \
56 middle = (left + right) / 2; \
58 key = cache->libs[middle].key; \
60 /* Make sure string table indices are not bogus before using \
61 them. */ \
62 if (! _dl_cache_verify_ptr (key)) \
63 { \
64 cmpres = 1; \
65 break; \
66 } \
68 /* Actually compare the entry with the key. */ \
69 cmpres = _dl_cache_libcmp (name, cache_data + key); \
70 if (__builtin_expect (cmpres == 0, 0)) \
71 { \
72 /* Found it. LEFT now marks the last entry for which we \
73 know the name is correct. */ \
74 left = middle; \
76 /* There might be entries with this name before the one we \
77 found. So we have to find the beginning. */ \
78 while (middle > 0) \
79 { \
80 __typeof__ (cache->libs[0].key) key; \
82 key = cache->libs[middle - 1].key; \
83 /* Make sure string table indices are not bogus before \
84 using them. */ \
85 if (! _dl_cache_verify_ptr (key) \
86 /* Actually compare the entry. */ \
87 || _dl_cache_libcmp (name, cache_data + key) != 0) \
88 break; \
89 --middle; \
90 } \
92 do \
93 { \
94 int flags; \
95 __typeof__ (cache->libs[0]) *lib = &cache->libs[middle]; \
97 /* Only perform the name test if necessary. */ \
98 if (middle > left \
99 /* We haven't seen this string so far. Test whether the \
100 index is ok and whether the name matches. Otherwise \
101 we are done. */ \
102 && (! _dl_cache_verify_ptr (lib->key) \
103 || (_dl_cache_libcmp (name, cache_data + lib->key) \
104 != 0))) \
105 break; \
107 flags = lib->flags; \
108 if (_dl_cache_check_flags (flags) \
109 && _dl_cache_verify_ptr (lib->value)) \
111 if (best == NULL || flags == GLRO(dl_correct_cache_id)) \
113 HWCAP_CHECK; \
114 best = cache_data + lib->value; \
116 if (flags == GLRO(dl_correct_cache_id)) \
117 /* We've found an exact match for the shared \
118 object and no general `ELF' release. Stop \
119 searching. */ \
120 break; \
124 while (++middle <= right); \
125 break; \
128 if (cmpres < 0) \
129 left = middle + 1; \
130 else \
131 right = middle - 1; \
134 while (0)
138 internal_function
139 _dl_cache_libcmp (const char *p1, const char *p2)
141 while (*p1 != '\0')
143 if (*p1 >= '0' && *p1 <= '9')
145 if (*p2 >= '0' && *p2 <= '9')
147 /* Must compare this numerically. */
148 int val1;
149 int val2;
151 val1 = *p1++ - '0';
152 val2 = *p2++ - '0';
153 while (*p1 >= '0' && *p1 <= '9')
154 val1 = val1 * 10 + *p1++ - '0';
155 while (*p2 >= '0' && *p2 <= '9')
156 val2 = val2 * 10 + *p2++ - '0';
157 if (val1 != val2)
158 return val1 - val2;
160 else
161 return 1;
163 else if (*p2 >= '0' && *p2 <= '9')
164 return -1;
165 else if (*p1 != *p2)
166 return *p1 - *p2;
167 else
169 ++p1;
170 ++p2;
173 return *p1 - *p2;
177 /* Look up NAME in ld.so.cache and return the file name stored there,
178 or null if none is found. */
180 const char *
181 internal_function
182 _dl_load_cache_lookup (const char *name)
184 int left, right, middle;
185 int cmpres;
186 const char *cache_data;
187 uint32_t cache_data_size;
188 const char *best;
190 /* Print a message if the loading of libs is traced. */
191 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0))
192 _dl_debug_printf (" search cache=%s\n", LD_SO_CACHE);
194 if (cache == NULL)
196 /* Read the contents of the file. */
197 void *file = _dl_sysdep_read_whole_file (LD_SO_CACHE, &cachesize,
198 PROT_READ);
200 /* We can handle three different cache file formats here:
201 - the old libc5/glibc2.0/2.1 format
202 - the old format with the new format in it
203 - only the new format
204 The following checks if the cache contains any of these formats. */
205 if (file != MAP_FAILED && cachesize > sizeof *cache
206 && memcmp (file, CACHEMAGIC, sizeof CACHEMAGIC - 1) == 0)
208 size_t offset;
209 /* Looks ok. */
210 cache = file;
212 /* Check for new version. */
213 offset = ALIGN_CACHE (sizeof (struct cache_file)
214 + cache->nlibs * sizeof (struct file_entry));
216 cache_new = (struct cache_file_new *) ((void *) cache + offset);
217 if (cachesize < (offset + sizeof (struct cache_file_new))
218 || memcmp (cache_new->magic, CACHEMAGIC_VERSION_NEW,
219 sizeof CACHEMAGIC_VERSION_NEW - 1) != 0)
220 cache_new = (void *) -1;
222 else if (file != MAP_FAILED && cachesize > sizeof *cache_new
223 && memcmp (file, CACHEMAGIC_VERSION_NEW,
224 sizeof CACHEMAGIC_VERSION_NEW - 1) == 0)
226 cache_new = file;
227 cache = file;
229 else
231 if (file != MAP_FAILED)
232 __munmap (file, cachesize);
233 cache = (void *) -1;
236 assert (cache != NULL);
239 if (cache == (void *) -1)
240 /* Previously looked for the cache file and didn't find it. */
241 return NULL;
243 best = NULL;
245 if (cache_new != (void *) -1)
247 uint64_t platform;
249 /* This is where the strings start. */
250 cache_data = (const char *) cache_new;
252 /* Now we can compute how large the string table is. */
253 cache_data_size = (const char *) cache + cachesize - cache_data;
255 platform = _dl_string_platform (GLRO(dl_platform));
256 if (platform != (uint64_t) -1)
257 platform = 1ULL << platform;
259 #define _DL_HWCAP_TLS_MASK (1LL << 63)
260 uint64_t hwcap_exclude = ~((GLRO(dl_hwcap) & GLRO(dl_hwcap_mask))
261 | _DL_HWCAP_PLATFORM | _DL_HWCAP_TLS_MASK);
263 /* Only accept hwcap if it's for the right platform. */
264 #define HWCAP_CHECK \
265 if (lib->hwcap & hwcap_exclude) \
266 continue; \
267 if (GLRO(dl_osversion) && lib->osversion > GLRO(dl_osversion)) \
268 continue; \
269 if (_DL_PLATFORMS_COUNT \
270 && (lib->hwcap & _DL_HWCAP_PLATFORM) != 0 \
271 && (lib->hwcap & _DL_HWCAP_PLATFORM) != platform) \
272 continue
273 SEARCH_CACHE (cache_new);
275 else
277 /* This is where the strings start. */
278 cache_data = (const char *) &cache->libs[cache->nlibs];
280 /* Now we can compute how large the string table is. */
281 cache_data_size = (const char *) cache + cachesize - cache_data;
283 #undef HWCAP_CHECK
284 #define HWCAP_CHECK do {} while (0)
285 SEARCH_CACHE (cache);
288 /* Print our result if wanted. */
289 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0)
290 && best != NULL)
291 _dl_debug_printf (" trying file=%s\n", best);
293 return best;
296 #ifndef MAP_COPY
297 /* If the system does not support MAP_COPY we cannot leave the file open
298 all the time since this would create problems when the file is replaced.
299 Therefore we provide this function to close the file and open it again
300 once needed. */
301 void
302 _dl_unload_cache (void)
304 if (cache != NULL && cache != (struct cache_file *) -1)
306 __munmap (cache, cachesize);
307 cache = NULL;
310 #endif