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266180eb | 1 | /* Support for dynamic linking code in static libc. |
568035b7 | 2 | Copyright (C) 1996-2013 Free Software Foundation, Inc. |
afd4eb37 | 3 | This file is part of the GNU C Library. |
266180eb | 4 | |
afd4eb37 | 5 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
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. | |
266180eb | 9 | |
afd4eb37 UD |
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 | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
266180eb | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
266180eb | 18 | |
266180eb RM |
19 | /* This file defines some things that for the dynamic linker are defined in |
20 | rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking. */ | |
21 | ||
3c720987 | 22 | #include <errno.h> |
8e17ea58 | 23 | #include <libintl.h> |
b13927da | 24 | #include <stdlib.h> |
0a54e401 | 25 | #include <unistd.h> |
32b4c839 | 26 | #include <sys/param.h> |
a42195db | 27 | #include <ldsodefs.h> |
0a54e401 | 28 | #include <dl-machine.h> |
cf197e41 | 29 | #include <bits/libc-lock.h> |
5688da55 | 30 | #include <dl-cache.h> |
74955460 | 31 | #include <dl-librecon.h> |
594d423a | 32 | #include <dl-procinfo.h> |
74955460 | 33 | #include <unsecvars.h> |
3b5c1b57 | 34 | #include <hp-timing.h> |
30950a5f | 35 | #include <stackinfo.h> |
b13927da | 36 | |
266180eb RM |
37 | extern char *__progname; |
38 | char **_dl_argv = &__progname; /* This is checked for some error messages. */ | |
39 | ||
0a54e401 UD |
40 | /* Name of the architecture. */ |
41 | const char *_dl_platform; | |
42 | size_t _dl_platformlen; | |
3c720987 | 43 | |
62dcee57 | 44 | int _dl_debug_mask; |
12b5b6b7 | 45 | int _dl_lazy; |
97fd3a30 | 46 | ElfW(Addr) _dl_use_load_bias = -2; |
dec126b4 | 47 | int _dl_dynamic_weak; |
0a54e401 | 48 | |
b13927da UD |
49 | /* If nonzero print warnings about problematic situations. */ |
50 | int _dl_verbose; | |
51 | ||
3996f34b UD |
52 | /* We never do profiling. */ |
53 | const char *_dl_profile; | |
53bfdc1c | 54 | const char *_dl_profile_output; |
3996f34b | 55 | |
fcf70d41 UD |
56 | /* Names of shared object for which the RUNPATHs and RPATHs should be |
57 | ignored. */ | |
b0a01055 | 58 | const char *_dl_inhibit_rpath; |
310930c1 | 59 | |
a3d6fb9b UD |
60 | /* The map for the object we will profile. */ |
61 | struct link_map *_dl_profile_map; | |
62 | ||
c0fb8a56 UD |
63 | /* This is the address of the last stack address ever used. */ |
64 | void *__libc_stack_end; | |
65 | ||
f787edde UD |
66 | /* Path where the binary is found. */ |
67 | const char *_dl_origin_path; | |
68 | ||
f53c03c2 UD |
69 | /* Nonzero if runtime lookup should not update the .got/.plt. */ |
70 | int _dl_bind_not; | |
71 | ||
c0f62c56 UD |
72 | /* Namespace information. */ |
73 | struct link_namespaces _dl_ns[DL_NNS]; | |
22c83193 | 74 | size_t _dl_nns; |
be935610 | 75 | |
bed12f78 UD |
76 | /* Incremented whenever something may have been added to dl_loaded. */ |
77 | unsigned long long _dl_load_adds; | |
bed12f78 | 78 | |
be935610 | 79 | /* Fake scope. In dynamically linked binaries this is the scope of the |
604510f7 | 80 | main application but here we don't have something like this. So |
be935610 | 81 | create a fake scope containing nothing. */ |
604510f7 | 82 | struct r_scope_elem _dl_initial_searchlist; |
be935610 | 83 | |
ce6e047f | 84 | #ifndef HAVE_INLINED_SYSCALLS |
9ad04ff7 UD |
85 | /* Nonzero during startup. */ |
86 | int _dl_starting_up = 1; | |
ce6e047f | 87 | #endif |
9ad04ff7 | 88 | |
965cb60a UD |
89 | /* Random data provided by the kernel. */ |
90 | void *_dl_random; | |
91 | ||
ccdf0cab UD |
92 | /* Get architecture specific initializer. */ |
93 | #include <dl-procinfo.c> | |
94 | ||
eaad82e0 UD |
95 | /* We expect less than a second for relocation. */ |
96 | #ifdef HP_SMALL_TIMING_AVAIL | |
97 | # undef HP_TIMING_AVAIL | |
98 | # define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL | |
99 | #endif | |
100 | ||
5fc48cd7 | 101 | /* Initial value of the CPU clock. */ |
eaad82e0 | 102 | #ifndef HP_TIMING_NONAVAIL |
3b5c1b57 | 103 | hp_timing_t _dl_cpuclock_offset; |
5fc48cd7 UD |
104 | #endif |
105 | ||
adc12574 | 106 | void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls; |
adc12574 | 107 | |
32b4c839 | 108 | size_t _dl_pagesize = EXEC_PAGESIZE; |
d6b5d570 | 109 | |
73d65cc3 SP |
110 | int _dl_inhibit_cache; |
111 | ||
d6b5d570 UD |
112 | unsigned int _dl_osversion; |
113 | ||
114 | /* All known directories in sorted order. */ | |
115 | struct r_search_path_elem *_dl_all_dirs; | |
116 | ||
117 | /* All directories after startup. */ | |
118 | struct r_search_path_elem *_dl_init_all_dirs; | |
119 | ||
120 | /* The object to be initialized first. */ | |
121 | struct link_map *_dl_initfirst; | |
122 | ||
5688da55 UD |
123 | /* Descriptor to write debug messages to. */ |
124 | int _dl_debug_fd = STDERR_FILENO; | |
125 | ||
126 | int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID; | |
127 | ||
c7683a6d | 128 | ElfW(auxv_t) *_dl_auxv; |
172ce013 | 129 | ElfW(Phdr) *_dl_phdr; |
fcda29e2 | 130 | size_t _dl_phnum; |
ab1d521d | 131 | uint64_t _dl_hwcap __attribute__ ((nocommon)); |
172ce013 | 132 | |
7bfa311f RM |
133 | /* This is not initialized to HWCAP_IMPORTANT, matching the definition |
134 | of _dl_important_hwcaps, below, where no hwcap strings are ever | |
135 | used. This mask is still used to mediate the lookups in the cache | |
136 | file. Since there is no way to set this nonzero (we don't grok the | |
137 | LD_HWCAP_MASK environment variable here), there is no real point in | |
138 | setting _dl_hwcap nonzero below, but we do anyway. */ | |
139 | uint64_t _dl_hwcap_mask __attribute__ ((nocommon)); | |
140 | ||
30950a5f RA |
141 | /* Prevailing state of the stack. Generally this includes PF_X, indicating it's |
142 | * executable but this isn't true for all platforms. */ | |
143 | ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS; | |
ecdeaac0 RM |
144 | |
145 | /* If loading a shared object requires that we make the stack executable | |
146 | when it was not, we do it by calling this function. | |
147 | It returns an errno code or zero on success. */ | |
d1fc817e | 148 | int (*_dl_make_stack_executable_hook) (void **) internal_function |
ecdeaac0 RM |
149 | = _dl_make_stack_executable; |
150 | ||
151 | ||
df94b641 UD |
152 | /* Function in libpthread to wait for termination of lookups. */ |
153 | void (*_dl_wait_lookup_done) (void); | |
154 | ||
e4eb675d UD |
155 | struct dl_scope_free_list *_dl_scope_free_list; |
156 | ||
5e289179 UD |
157 | #ifdef NEED_DL_SYSINFO |
158 | /* Needed for improved syscall handling on at least x86/Linux. */ | |
159 | uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT; | |
30e32d23 RM |
160 | #endif |
161 | #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO | |
f866314b UD |
162 | /* Address of the ELF headers in the vsyscall page. */ |
163 | const ElfW(Ehdr) *_dl_sysinfo_dso; | |
9cee5585 L |
164 | |
165 | struct link_map *_dl_sysinfo_map; | |
166 | ||
167 | # include "get-dynamic-info.h" | |
5e289179 | 168 | #endif |
d0d4f868 | 169 | #include "setup-vdso.h" |
5e289179 | 170 | |
cf197e41 UD |
171 | /* During the program run we must not modify the global data of |
172 | loaded shared object simultanously in two threads. Therefore we | |
173 | protect `_dl_open' and `_dl_close' in dl-close.c. | |
174 | ||
175 | This must be a recursive lock since the initializer function of | |
176 | the loaded object might as well require a call to this function. | |
177 | At this time it is not anymore a problem to modify the tables. */ | |
d3c9f895 | 178 | __rtld_lock_define_initialized_recursive (, _dl_load_lock) |
5a2a1d75 AS |
179 | /* This lock is used to keep __dl_iterate_phdr from inspecting the |
180 | list of loaded objects while an object is added to or removed from | |
181 | that list. */ | |
182 | __rtld_lock_define_initialized_recursive (, _dl_load_write_lock) | |
cf197e41 | 183 | |
f8f900ec | 184 | |
e4a5f77d | 185 | #ifdef HAVE_AUX_VECTOR |
d6b5d570 | 186 | int _dl_clktck; |
0a54e401 | 187 | |
e4a5f77d UD |
188 | void |
189 | internal_function | |
190 | _dl_aux_init (ElfW(auxv_t) *av) | |
b13927da | 191 | { |
be4d8038 UD |
192 | int seen = 0; |
193 | uid_t uid = 0; | |
194 | gid_t gid = 0; | |
195 | ||
c7683a6d | 196 | _dl_auxv = av; |
f8f900ec UD |
197 | for (; av->a_type != AT_NULL; ++av) |
198 | switch (av->a_type) | |
199 | { | |
200 | case AT_PAGESZ: | |
afdca0f2 | 201 | GLRO(dl_pagesize) = av->a_un.a_val; |
f8f900ec | 202 | break; |
f8f900ec | 203 | case AT_CLKTCK: |
afdca0f2 | 204 | GLRO(dl_clktck) = av->a_un.a_val; |
f8f900ec | 205 | break; |
fcda29e2 | 206 | case AT_PHDR: |
39fb308f | 207 | GL(dl_phdr) = (void *) av->a_un.a_val; |
fcda29e2 UD |
208 | break; |
209 | case AT_PHNUM: | |
210 | GL(dl_phnum) = av->a_un.a_val; | |
211 | break; | |
11bf8ce1 | 212 | case AT_HWCAP: |
ab1d521d | 213 | GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; |
11bf8ce1 | 214 | break; |
5df8349b UD |
215 | #ifdef NEED_DL_SYSINFO |
216 | case AT_SYSINFO: | |
217 | GL(dl_sysinfo) = av->a_un.a_val; | |
218 | break; | |
30e32d23 RM |
219 | #endif |
220 | #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO | |
221 | case AT_SYSINFO_EHDR: | |
39fb308f | 222 | GL(dl_sysinfo_dso) = (void *) av->a_un.a_val; |
30e32d23 | 223 | break; |
5df8349b | 224 | #endif |
be4d8038 UD |
225 | case AT_UID: |
226 | uid ^= av->a_un.a_val; | |
227 | seen |= 1; | |
228 | break; | |
229 | case AT_EUID: | |
230 | uid ^= av->a_un.a_val; | |
231 | seen |= 2; | |
232 | break; | |
233 | case AT_GID: | |
234 | gid ^= av->a_un.a_val; | |
235 | seen |= 4; | |
236 | break; | |
237 | case AT_EGID: | |
238 | gid ^= av->a_un.a_val; | |
239 | seen |= 8; | |
240 | break; | |
c801e765 RM |
241 | case AT_SECURE: |
242 | seen = -1; | |
243 | __libc_enable_secure = av->a_un.a_val; | |
244 | __libc_enable_secure_decided = 1; | |
245 | break; | |
965cb60a UD |
246 | case AT_RANDOM: |
247 | _dl_random = (void *) av->a_un.a_val; | |
248 | break; | |
47dbe62b RH |
249 | # ifdef DL_PLATFORM_AUXV |
250 | DL_PLATFORM_AUXV | |
251 | # endif | |
f8f900ec | 252 | } |
be4d8038 UD |
253 | if (seen == 0xf) |
254 | { | |
255 | __libc_enable_secure = uid != 0 || gid != 0; | |
256 | __libc_enable_secure_decided = 1; | |
257 | } | |
e4a5f77d | 258 | } |
155fd00c | 259 | #endif |
f8f900ec | 260 | |
e4a5f77d | 261 | |
d417e0ff UD |
262 | void |
263 | internal_function | |
264 | _dl_non_dynamic_init (void) | |
e4a5f77d | 265 | { |
eaad82e0 UD |
266 | if (HP_TIMING_AVAIL) |
267 | HP_TIMING_NOW (_dl_cpuclock_offset); | |
5fc48cd7 | 268 | |
f8f900ec UD |
269 | if (!_dl_pagesize) |
270 | _dl_pagesize = __getpagesize (); | |
271 | ||
272 | _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1; | |
e34b0f29 | 273 | |
9cee5585 L |
274 | /* Set up the data structures for the system-supplied DSO early, |
275 | so they can influence _dl_init_paths. */ | |
276 | setup_vdso (NULL, NULL); | |
277 | ||
0a54e401 UD |
278 | /* Initialize the data structures for the search paths for shared |
279 | objects. */ | |
b4debac9 | 280 | _dl_init_paths (getenv ("LD_LIBRARY_PATH")); |
0a54e401 | 281 | |
bc5fb037 AS |
282 | /* Remember the last search directory added at startup. */ |
283 | _dl_init_all_dirs = GL(dl_all_dirs); | |
284 | ||
12b5b6b7 UD |
285 | _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0'; |
286 | ||
f53c03c2 UD |
287 | _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0'; |
288 | ||
dec126b4 UD |
289 | _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0'; |
290 | ||
53bfdc1c UD |
291 | _dl_profile_output = getenv ("LD_PROFILE_OUTPUT"); |
292 | if (_dl_profile_output == NULL || _dl_profile_output[0] == '\0') | |
293 | _dl_profile_output | |
294 | = &"/var/tmp\0/var/profile"[__libc_enable_secure ? 9 : 0]; | |
295 | ||
74955460 UD |
296 | if (__libc_enable_secure) |
297 | { | |
c4e328a1 UD |
298 | static const char unsecure_envvars[] = |
299 | UNSECURE_ENVVARS | |
74955460 UD |
300 | #ifdef EXTRA_UNSECURE_ENVVARS |
301 | EXTRA_UNSECURE_ENVVARS | |
302 | #endif | |
c4e328a1 UD |
303 | ; |
304 | const char *cp = unsecure_envvars; | |
74955460 | 305 | |
c4e328a1 UD |
306 | while (cp < unsecure_envvars + sizeof (unsecure_envvars)) |
307 | { | |
308 | __unsetenv (cp); | |
309 | cp = (const char *) __rawmemchr (cp, '\0') + 1; | |
310 | } | |
74955460 UD |
311 | |
312 | if (__access ("/etc/suid-debug", F_OK) != 0) | |
c4e328a1 | 313 | __unsetenv ("MALLOC_CHECK_"); |
74955460 UD |
314 | } |
315 | ||
0a54e401 UD |
316 | #ifdef DL_PLATFORM_INIT |
317 | DL_PLATFORM_INIT; | |
318 | #endif | |
319 | ||
2402cdf3 RM |
320 | #ifdef DL_OSVERSION_INIT |
321 | DL_OSVERSION_INIT; | |
322 | #endif | |
323 | ||
0a54e401 UD |
324 | /* Now determine the length of the platform string. */ |
325 | if (_dl_platform != NULL) | |
326 | _dl_platformlen = strlen (_dl_platform); | |
ecdeaac0 RM |
327 | |
328 | /* Scan for a program header telling us the stack is nonexecutable. */ | |
329 | if (_dl_phdr != NULL) | |
330 | for (uint_fast16_t i = 0; i < _dl_phnum; ++i) | |
331 | if (_dl_phdr[i].p_type == PT_GNU_STACK) | |
332 | { | |
333 | _dl_stack_flags = _dl_phdr[i].p_flags; | |
334 | break; | |
335 | } | |
b13927da | 336 | } |
d417e0ff | 337 | |
5e289179 UD |
338 | #ifdef DL_SYSINFO_IMPLEMENTATION |
339 | DL_SYSINFO_IMPLEMENTATION | |
340 | #endif |