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266180eb | 1 | /* Support for dynamic linking code in static libc. |
04277e02 | 2 | Copyright (C) 1996-2019 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> |
e054f494 | 27 | #include <stdint.h> |
a42195db | 28 | #include <ldsodefs.h> |
0a54e401 | 29 | #include <dl-machine.h> |
ec999b8e | 30 | #include <libc-lock.h> |
5688da55 | 31 | #include <dl-cache.h> |
74955460 | 32 | #include <dl-librecon.h> |
594d423a | 33 | #include <dl-procinfo.h> |
74955460 | 34 | #include <unsecvars.h> |
3b5c1b57 | 35 | #include <hp-timing.h> |
30950a5f | 36 | #include <stackinfo.h> |
b13927da | 37 | |
266180eb RM |
38 | extern char *__progname; |
39 | char **_dl_argv = &__progname; /* This is checked for some error messages. */ | |
40 | ||
0a54e401 UD |
41 | /* Name of the architecture. */ |
42 | const char *_dl_platform; | |
43 | size_t _dl_platformlen; | |
3c720987 | 44 | |
62dcee57 | 45 | int _dl_debug_mask; |
12b5b6b7 | 46 | int _dl_lazy; |
97fd3a30 | 47 | ElfW(Addr) _dl_use_load_bias = -2; |
dec126b4 | 48 | int _dl_dynamic_weak; |
0a54e401 | 49 | |
b13927da UD |
50 | /* If nonzero print warnings about problematic situations. */ |
51 | int _dl_verbose; | |
52 | ||
3996f34b UD |
53 | /* We never do profiling. */ |
54 | const char *_dl_profile; | |
53bfdc1c | 55 | const char *_dl_profile_output; |
3996f34b | 56 | |
fcf70d41 UD |
57 | /* Names of shared object for which the RUNPATHs and RPATHs should be |
58 | ignored. */ | |
b0a01055 | 59 | const char *_dl_inhibit_rpath; |
310930c1 | 60 | |
a3d6fb9b UD |
61 | /* The map for the object we will profile. */ |
62 | struct link_map *_dl_profile_map; | |
63 | ||
c0fb8a56 UD |
64 | /* This is the address of the last stack address ever used. */ |
65 | void *__libc_stack_end; | |
66 | ||
f787edde UD |
67 | /* Path where the binary is found. */ |
68 | const char *_dl_origin_path; | |
69 | ||
f53c03c2 UD |
70 | /* Nonzero if runtime lookup should not update the .got/.plt. */ |
71 | int _dl_bind_not; | |
72 | ||
f91f1c0f MR |
73 | /* A dummy link map for the executable, used by dlopen to access the global |
74 | scope. We don't export any symbols ourselves, so this can be minimal. */ | |
75 | static struct link_map _dl_main_map = | |
76 | { | |
77 | .l_name = (char *) "", | |
78 | .l_real = &_dl_main_map, | |
79 | .l_ns = LM_ID_BASE, | |
80 | .l_libname = &(struct libname_list) { .name = "", .dont_free = 1 }, | |
81 | .l_searchlist = | |
82 | { | |
83 | .r_list = &(struct link_map *) { &_dl_main_map }, | |
84 | .r_nlist = 1, | |
85 | }, | |
86 | .l_symbolic_searchlist = { .r_list = &(struct link_map *) { NULL } }, | |
87 | .l_type = lt_executable, | |
88 | .l_scope_mem = { &_dl_main_map.l_searchlist }, | |
89 | .l_scope_max = (sizeof (_dl_main_map.l_scope_mem) | |
90 | / sizeof (_dl_main_map.l_scope_mem[0])), | |
91 | .l_scope = _dl_main_map.l_scope_mem, | |
92 | .l_local_scope = { &_dl_main_map.l_searchlist }, | |
93 | .l_used = 1, | |
94 | .l_tls_offset = NO_TLS_OFFSET, | |
95 | .l_serial = 1, | |
96 | }; | |
97 | ||
c0f62c56 | 98 | /* Namespace information. */ |
f91f1c0f MR |
99 | struct link_namespaces _dl_ns[DL_NNS] = |
100 | { | |
101 | [LM_ID_BASE] = | |
102 | { | |
103 | ._ns_loaded = &_dl_main_map, | |
104 | ._ns_nloaded = 1, | |
105 | ._ns_main_searchlist = &_dl_main_map.l_searchlist, | |
106 | } | |
107 | }; | |
108 | size_t _dl_nns = 1; | |
be935610 | 109 | |
bed12f78 | 110 | /* Incremented whenever something may have been added to dl_loaded. */ |
f91f1c0f | 111 | unsigned long long _dl_load_adds = 1; |
bed12f78 | 112 | |
f91f1c0f MR |
113 | /* Fake scope of the main application. */ |
114 | struct r_scope_elem _dl_initial_searchlist = | |
115 | { | |
116 | .r_list = &(struct link_map *) { &_dl_main_map }, | |
117 | .r_nlist = 1, | |
118 | }; | |
be935610 | 119 | |
ce6e047f | 120 | #ifndef HAVE_INLINED_SYSCALLS |
9ad04ff7 UD |
121 | /* Nonzero during startup. */ |
122 | int _dl_starting_up = 1; | |
ce6e047f | 123 | #endif |
9ad04ff7 | 124 | |
965cb60a UD |
125 | /* Random data provided by the kernel. */ |
126 | void *_dl_random; | |
127 | ||
ccdf0cab | 128 | /* Get architecture specific initializer. */ |
4a306ef1 | 129 | #include <dl-procruntime.c> |
ccdf0cab UD |
130 | #include <dl-procinfo.c> |
131 | ||
adc12574 | 132 | void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls; |
adc12574 | 133 | |
32b4c839 | 134 | size_t _dl_pagesize = EXEC_PAGESIZE; |
d6b5d570 | 135 | |
73d65cc3 SP |
136 | int _dl_inhibit_cache; |
137 | ||
d6b5d570 UD |
138 | unsigned int _dl_osversion; |
139 | ||
140 | /* All known directories in sorted order. */ | |
141 | struct r_search_path_elem *_dl_all_dirs; | |
142 | ||
143 | /* All directories after startup. */ | |
144 | struct r_search_path_elem *_dl_init_all_dirs; | |
145 | ||
146 | /* The object to be initialized first. */ | |
147 | struct link_map *_dl_initfirst; | |
148 | ||
5688da55 UD |
149 | /* Descriptor to write debug messages to. */ |
150 | int _dl_debug_fd = STDERR_FILENO; | |
151 | ||
152 | int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID; | |
153 | ||
c7683a6d | 154 | ElfW(auxv_t) *_dl_auxv; |
dc0a0263 | 155 | const ElfW(Phdr) *_dl_phdr; |
fcda29e2 | 156 | size_t _dl_phnum; |
ab1d521d | 157 | uint64_t _dl_hwcap __attribute__ ((nocommon)); |
1ae8bfe0 | 158 | uint64_t _dl_hwcap2 __attribute__ ((nocommon)); |
172ce013 | 159 | |
95e7cf29 MR |
160 | /* The value of the FPU control word the kernel will preset in hardware. */ |
161 | fpu_control_t _dl_fpu_control = _FPU_DEFAULT; | |
162 | ||
ff08fc59 | 163 | #if !HAVE_TUNABLES |
7bfa311f RM |
164 | /* This is not initialized to HWCAP_IMPORTANT, matching the definition |
165 | of _dl_important_hwcaps, below, where no hwcap strings are ever | |
166 | used. This mask is still used to mediate the lookups in the cache | |
167 | file. Since there is no way to set this nonzero (we don't grok the | |
168 | LD_HWCAP_MASK environment variable here), there is no real point in | |
169 | setting _dl_hwcap nonzero below, but we do anyway. */ | |
170 | uint64_t _dl_hwcap_mask __attribute__ ((nocommon)); | |
ff08fc59 | 171 | #endif |
7bfa311f | 172 | |
30950a5f RA |
173 | /* Prevailing state of the stack. Generally this includes PF_X, indicating it's |
174 | * executable but this isn't true for all platforms. */ | |
175 | ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS; | |
ecdeaac0 RM |
176 | |
177 | /* If loading a shared object requires that we make the stack executable | |
178 | when it was not, we do it by calling this function. | |
179 | It returns an errno code or zero on success. */ | |
e1d2ae8d | 180 | int (*_dl_make_stack_executable_hook) (void **) = _dl_make_stack_executable; |
ecdeaac0 RM |
181 | |
182 | ||
df94b641 UD |
183 | /* Function in libpthread to wait for termination of lookups. */ |
184 | void (*_dl_wait_lookup_done) (void); | |
185 | ||
a5df0318 ST |
186 | #if !THREAD_GSCOPE_IN_TCB |
187 | int _dl_thread_gscope_count; | |
188 | #endif | |
e4eb675d UD |
189 | struct dl_scope_free_list *_dl_scope_free_list; |
190 | ||
5e289179 UD |
191 | #ifdef NEED_DL_SYSINFO |
192 | /* Needed for improved syscall handling on at least x86/Linux. */ | |
193 | uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT; | |
30e32d23 | 194 | #endif |
7775448e | 195 | #ifdef NEED_DL_SYSINFO_DSO |
f866314b UD |
196 | /* Address of the ELF headers in the vsyscall page. */ |
197 | const ElfW(Ehdr) *_dl_sysinfo_dso; | |
9cee5585 L |
198 | |
199 | struct link_map *_dl_sysinfo_map; | |
200 | ||
201 | # include "get-dynamic-info.h" | |
5e289179 | 202 | #endif |
d0d4f868 | 203 | #include "setup-vdso.h" |
5e289179 | 204 | |
cf197e41 UD |
205 | /* During the program run we must not modify the global data of |
206 | loaded shared object simultanously in two threads. Therefore we | |
207 | protect `_dl_open' and `_dl_close' in dl-close.c. | |
208 | ||
209 | This must be a recursive lock since the initializer function of | |
210 | the loaded object might as well require a call to this function. | |
211 | At this time it is not anymore a problem to modify the tables. */ | |
d3c9f895 | 212 | __rtld_lock_define_initialized_recursive (, _dl_load_lock) |
5a2a1d75 AS |
213 | /* This lock is used to keep __dl_iterate_phdr from inspecting the |
214 | list of loaded objects while an object is added to or removed from | |
215 | that list. */ | |
216 | __rtld_lock_define_initialized_recursive (, _dl_load_write_lock) | |
cf197e41 | 217 | |
f8f900ec | 218 | |
e4a5f77d | 219 | #ifdef HAVE_AUX_VECTOR |
d6b5d570 | 220 | int _dl_clktck; |
0a54e401 | 221 | |
e4a5f77d | 222 | void |
e4a5f77d | 223 | _dl_aux_init (ElfW(auxv_t) *av) |
b13927da | 224 | { |
be4d8038 UD |
225 | int seen = 0; |
226 | uid_t uid = 0; | |
227 | gid_t gid = 0; | |
228 | ||
c7683a6d | 229 | _dl_auxv = av; |
f8f900ec UD |
230 | for (; av->a_type != AT_NULL; ++av) |
231 | switch (av->a_type) | |
232 | { | |
233 | case AT_PAGESZ: | |
aefc9b8c RM |
234 | if (av->a_un.a_val != 0) |
235 | GLRO(dl_pagesize) = av->a_un.a_val; | |
f8f900ec | 236 | break; |
f8f900ec | 237 | case AT_CLKTCK: |
afdca0f2 | 238 | GLRO(dl_clktck) = av->a_un.a_val; |
f8f900ec | 239 | break; |
fcda29e2 | 240 | case AT_PHDR: |
dc0a0263 | 241 | GL(dl_phdr) = (const void *) av->a_un.a_val; |
fcda29e2 UD |
242 | break; |
243 | case AT_PHNUM: | |
244 | GL(dl_phnum) = av->a_un.a_val; | |
245 | break; | |
76c5ae00 CES |
246 | case AT_PLATFORM: |
247 | GLRO(dl_platform) = (void *) av->a_un.a_val; | |
248 | break; | |
11bf8ce1 | 249 | case AT_HWCAP: |
ab1d521d | 250 | GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; |
11bf8ce1 | 251 | break; |
1ae8bfe0 RA |
252 | case AT_HWCAP2: |
253 | GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; | |
254 | break; | |
95e7cf29 MR |
255 | case AT_FPUCW: |
256 | GLRO(dl_fpu_control) = av->a_un.a_val; | |
257 | break; | |
5df8349b UD |
258 | #ifdef NEED_DL_SYSINFO |
259 | case AT_SYSINFO: | |
260 | GL(dl_sysinfo) = av->a_un.a_val; | |
261 | break; | |
30e32d23 | 262 | #endif |
7775448e | 263 | #ifdef NEED_DL_SYSINFO_DSO |
30e32d23 | 264 | case AT_SYSINFO_EHDR: |
39fb308f | 265 | GL(dl_sysinfo_dso) = (void *) av->a_un.a_val; |
30e32d23 | 266 | break; |
5df8349b | 267 | #endif |
be4d8038 UD |
268 | case AT_UID: |
269 | uid ^= av->a_un.a_val; | |
270 | seen |= 1; | |
271 | break; | |
272 | case AT_EUID: | |
273 | uid ^= av->a_un.a_val; | |
274 | seen |= 2; | |
275 | break; | |
276 | case AT_GID: | |
277 | gid ^= av->a_un.a_val; | |
278 | seen |= 4; | |
279 | break; | |
280 | case AT_EGID: | |
281 | gid ^= av->a_un.a_val; | |
282 | seen |= 8; | |
283 | break; | |
c801e765 RM |
284 | case AT_SECURE: |
285 | seen = -1; | |
286 | __libc_enable_secure = av->a_un.a_val; | |
287 | __libc_enable_secure_decided = 1; | |
288 | break; | |
965cb60a UD |
289 | case AT_RANDOM: |
290 | _dl_random = (void *) av->a_un.a_val; | |
291 | break; | |
47dbe62b RH |
292 | # ifdef DL_PLATFORM_AUXV |
293 | DL_PLATFORM_AUXV | |
294 | # endif | |
f8f900ec | 295 | } |
be4d8038 UD |
296 | if (seen == 0xf) |
297 | { | |
298 | __libc_enable_secure = uid != 0 || gid != 0; | |
299 | __libc_enable_secure_decided = 1; | |
300 | } | |
e4a5f77d | 301 | } |
155fd00c | 302 | #endif |
f8f900ec | 303 | |
e4a5f77d | 304 | |
d417e0ff | 305 | void |
d417e0ff | 306 | _dl_non_dynamic_init (void) |
e4a5f77d | 307 | { |
f91f1c0f | 308 | _dl_main_map.l_origin = _dl_get_origin (); |
0d23a5c1 MR |
309 | _dl_main_map.l_phdr = GL(dl_phdr); |
310 | _dl_main_map.l_phnum = GL(dl_phnum); | |
f91f1c0f | 311 | |
f8f900ec | 312 | _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1; |
e34b0f29 | 313 | |
9cee5585 L |
314 | /* Set up the data structures for the system-supplied DSO early, |
315 | so they can influence _dl_init_paths. */ | |
316 | setup_vdso (NULL, NULL); | |
317 | ||
0a54e401 UD |
318 | /* Initialize the data structures for the search paths for shared |
319 | objects. */ | |
b4debac9 | 320 | _dl_init_paths (getenv ("LD_LIBRARY_PATH")); |
0a54e401 | 321 | |
bc5fb037 AS |
322 | /* Remember the last search directory added at startup. */ |
323 | _dl_init_all_dirs = GL(dl_all_dirs); | |
324 | ||
12b5b6b7 UD |
325 | _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0'; |
326 | ||
f53c03c2 UD |
327 | _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0'; |
328 | ||
dec126b4 UD |
329 | _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0'; |
330 | ||
53bfdc1c UD |
331 | _dl_profile_output = getenv ("LD_PROFILE_OUTPUT"); |
332 | if (_dl_profile_output == NULL || _dl_profile_output[0] == '\0') | |
333 | _dl_profile_output | |
334 | = &"/var/tmp\0/var/profile"[__libc_enable_secure ? 9 : 0]; | |
335 | ||
74955460 UD |
336 | if (__libc_enable_secure) |
337 | { | |
c4e328a1 UD |
338 | static const char unsecure_envvars[] = |
339 | UNSECURE_ENVVARS | |
74955460 UD |
340 | #ifdef EXTRA_UNSECURE_ENVVARS |
341 | EXTRA_UNSECURE_ENVVARS | |
342 | #endif | |
c4e328a1 UD |
343 | ; |
344 | const char *cp = unsecure_envvars; | |
74955460 | 345 | |
c4e328a1 UD |
346 | while (cp < unsecure_envvars + sizeof (unsecure_envvars)) |
347 | { | |
348 | __unsetenv (cp); | |
349 | cp = (const char *) __rawmemchr (cp, '\0') + 1; | |
350 | } | |
74955460 | 351 | |
67e58f39 | 352 | #if !HAVE_TUNABLES |
74955460 | 353 | if (__access ("/etc/suid-debug", F_OK) != 0) |
c4e328a1 | 354 | __unsetenv ("MALLOC_CHECK_"); |
67e58f39 | 355 | #endif |
74955460 UD |
356 | } |
357 | ||
0a54e401 UD |
358 | #ifdef DL_PLATFORM_INIT |
359 | DL_PLATFORM_INIT; | |
360 | #endif | |
361 | ||
2402cdf3 RM |
362 | #ifdef DL_OSVERSION_INIT |
363 | DL_OSVERSION_INIT; | |
364 | #endif | |
365 | ||
0a54e401 UD |
366 | /* Now determine the length of the platform string. */ |
367 | if (_dl_platform != NULL) | |
368 | _dl_platformlen = strlen (_dl_platform); | |
ecdeaac0 RM |
369 | |
370 | /* Scan for a program header telling us the stack is nonexecutable. */ | |
371 | if (_dl_phdr != NULL) | |
372 | for (uint_fast16_t i = 0; i < _dl_phnum; ++i) | |
373 | if (_dl_phdr[i].p_type == PT_GNU_STACK) | |
374 | { | |
375 | _dl_stack_flags = _dl_phdr[i].p_flags; | |
376 | break; | |
377 | } | |
b13927da | 378 | } |
d417e0ff | 379 | |
5e289179 UD |
380 | #ifdef DL_SYSINFO_IMPLEMENTATION |
381 | DL_SYSINFO_IMPLEMENTATION | |
382 | #endif | |
9d7a3741 L |
383 | |
384 | #if ENABLE_STATIC_PIE | |
385 | /* Since relocation to hidden _dl_main_map causes relocation overflow on | |
386 | aarch64, a function is used to get the address of _dl_main_map. */ | |
387 | ||
388 | struct link_map * | |
389 | _dl_get_dl_main_map (void) | |
390 | { | |
391 | return &_dl_main_map; | |
392 | } | |
393 | #endif |