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266180eb | 1 | /* Support for dynamic linking code in static libc. |
581c785b | 2 | Copyright (C) 1996-2022 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 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://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 | ||
47618209 SN |
22 | #include <string.h> |
23 | /* Mark symbols hidden in static PIE for early self relocation to work. | |
24 | Note: string.h may have ifuncs which cannot be hidden on i686. */ | |
25 | #if BUILD_PIE_DEFAULT | |
26 | # pragma GCC visibility push(hidden) | |
27 | #endif | |
3c720987 | 28 | #include <errno.h> |
8e17ea58 | 29 | #include <libintl.h> |
b13927da | 30 | #include <stdlib.h> |
0a54e401 | 31 | #include <unistd.h> |
32b4c839 | 32 | #include <sys/param.h> |
e054f494 | 33 | #include <stdint.h> |
a42195db | 34 | #include <ldsodefs.h> |
0a54e401 | 35 | #include <dl-machine.h> |
ec999b8e | 36 | #include <libc-lock.h> |
5688da55 | 37 | #include <dl-cache.h> |
74955460 | 38 | #include <dl-librecon.h> |
594d423a | 39 | #include <dl-procinfo.h> |
74955460 | 40 | #include <unsecvars.h> |
3b5c1b57 | 41 | #include <hp-timing.h> |
30950a5f | 42 | #include <stackinfo.h> |
1bdda52f AZ |
43 | #include <dl-vdso.h> |
44 | #include <dl-vdso-setup.h> | |
18363b4f | 45 | #include <dl-auxv.h> |
5d28a896 | 46 | #include <dl-find_object.h> |
73fc4e28 | 47 | #include <array_length.h> |
b13927da | 48 | |
266180eb RM |
49 | extern char *__progname; |
50 | char **_dl_argv = &__progname; /* This is checked for some error messages. */ | |
51 | ||
0a54e401 UD |
52 | /* Name of the architecture. */ |
53 | const char *_dl_platform; | |
54 | size_t _dl_platformlen; | |
3c720987 | 55 | |
62dcee57 | 56 | int _dl_debug_mask; |
12b5b6b7 | 57 | int _dl_lazy; |
dec126b4 | 58 | int _dl_dynamic_weak; |
0a54e401 | 59 | |
b13927da UD |
60 | /* If nonzero print warnings about problematic situations. */ |
61 | int _dl_verbose; | |
62 | ||
3996f34b UD |
63 | /* We never do profiling. */ |
64 | const char *_dl_profile; | |
53bfdc1c | 65 | const char *_dl_profile_output; |
3996f34b | 66 | |
fcf70d41 UD |
67 | /* Names of shared object for which the RUNPATHs and RPATHs should be |
68 | ignored. */ | |
b0a01055 | 69 | const char *_dl_inhibit_rpath; |
310930c1 | 70 | |
a3d6fb9b UD |
71 | /* The map for the object we will profile. */ |
72 | struct link_map *_dl_profile_map; | |
73 | ||
c0fb8a56 UD |
74 | /* This is the address of the last stack address ever used. */ |
75 | void *__libc_stack_end; | |
76 | ||
f787edde UD |
77 | /* Path where the binary is found. */ |
78 | const char *_dl_origin_path; | |
79 | ||
f53c03c2 UD |
80 | /* Nonzero if runtime lookup should not update the .got/.plt. */ |
81 | int _dl_bind_not; | |
82 | ||
f91f1c0f MR |
83 | /* A dummy link map for the executable, used by dlopen to access the global |
84 | scope. We don't export any symbols ourselves, so this can be minimal. */ | |
85 | static struct link_map _dl_main_map = | |
86 | { | |
87 | .l_name = (char *) "", | |
88 | .l_real = &_dl_main_map, | |
89 | .l_ns = LM_ID_BASE, | |
90 | .l_libname = &(struct libname_list) { .name = "", .dont_free = 1 }, | |
91 | .l_searchlist = | |
92 | { | |
93 | .r_list = &(struct link_map *) { &_dl_main_map }, | |
94 | .r_nlist = 1, | |
95 | }, | |
96 | .l_symbolic_searchlist = { .r_list = &(struct link_map *) { NULL } }, | |
97 | .l_type = lt_executable, | |
98 | .l_scope_mem = { &_dl_main_map.l_searchlist }, | |
99 | .l_scope_max = (sizeof (_dl_main_map.l_scope_mem) | |
100 | / sizeof (_dl_main_map.l_scope_mem[0])), | |
101 | .l_scope = _dl_main_map.l_scope_mem, | |
102 | .l_local_scope = { &_dl_main_map.l_searchlist }, | |
103 | .l_used = 1, | |
104 | .l_tls_offset = NO_TLS_OFFSET, | |
105 | .l_serial = 1, | |
106 | }; | |
107 | ||
c0f62c56 | 108 | /* Namespace information. */ |
f91f1c0f MR |
109 | struct link_namespaces _dl_ns[DL_NNS] = |
110 | { | |
111 | [LM_ID_BASE] = | |
112 | { | |
113 | ._ns_loaded = &_dl_main_map, | |
114 | ._ns_nloaded = 1, | |
115 | ._ns_main_searchlist = &_dl_main_map.l_searchlist, | |
116 | } | |
117 | }; | |
118 | size_t _dl_nns = 1; | |
be935610 | 119 | |
bed12f78 | 120 | /* Incremented whenever something may have been added to dl_loaded. */ |
f91f1c0f | 121 | unsigned long long _dl_load_adds = 1; |
bed12f78 | 122 | |
f91f1c0f MR |
123 | /* Fake scope of the main application. */ |
124 | struct r_scope_elem _dl_initial_searchlist = | |
125 | { | |
126 | .r_list = &(struct link_map *) { &_dl_main_map }, | |
127 | .r_nlist = 1, | |
128 | }; | |
be935610 | 129 | |
ce6e047f | 130 | #ifndef HAVE_INLINED_SYSCALLS |
9ad04ff7 UD |
131 | /* Nonzero during startup. */ |
132 | int _dl_starting_up = 1; | |
ce6e047f | 133 | #endif |
9ad04ff7 | 134 | |
965cb60a UD |
135 | /* Random data provided by the kernel. */ |
136 | void *_dl_random; | |
137 | ||
ccdf0cab | 138 | /* Get architecture specific initializer. */ |
4a306ef1 | 139 | #include <dl-procruntime.c> |
ccdf0cab UD |
140 | #include <dl-procinfo.c> |
141 | ||
32b4c839 | 142 | size_t _dl_pagesize = EXEC_PAGESIZE; |
d6b5d570 | 143 | |
6c57d320 L |
144 | size_t _dl_minsigstacksize = CONSTANT_MINSIGSTKSZ; |
145 | ||
73d65cc3 SP |
146 | int _dl_inhibit_cache; |
147 | ||
d6b5d570 UD |
148 | unsigned int _dl_osversion; |
149 | ||
150 | /* All known directories in sorted order. */ | |
151 | struct r_search_path_elem *_dl_all_dirs; | |
152 | ||
153 | /* All directories after startup. */ | |
154 | struct r_search_path_elem *_dl_init_all_dirs; | |
155 | ||
156 | /* The object to be initialized first. */ | |
157 | struct link_map *_dl_initfirst; | |
158 | ||
5688da55 UD |
159 | /* Descriptor to write debug messages to. */ |
160 | int _dl_debug_fd = STDERR_FILENO; | |
161 | ||
162 | int _dl_correct_cache_id = _DL_CACHE_DEFAULT_ID; | |
163 | ||
c7683a6d | 164 | ElfW(auxv_t) *_dl_auxv; |
dc0a0263 | 165 | const ElfW(Phdr) *_dl_phdr; |
fcda29e2 | 166 | size_t _dl_phnum; |
7c241325 FW |
167 | uint64_t _dl_hwcap; |
168 | uint64_t _dl_hwcap2; | |
172ce013 | 169 | |
15a0c573 CLT |
170 | enum dso_sort_algorithm _dl_dso_sort_algo; |
171 | ||
95e7cf29 MR |
172 | /* The value of the FPU control word the kernel will preset in hardware. */ |
173 | fpu_control_t _dl_fpu_control = _FPU_DEFAULT; | |
174 | ||
ff08fc59 | 175 | #if !HAVE_TUNABLES |
7bfa311f RM |
176 | /* This is not initialized to HWCAP_IMPORTANT, matching the definition |
177 | of _dl_important_hwcaps, below, where no hwcap strings are ever | |
178 | used. This mask is still used to mediate the lookups in the cache | |
179 | file. Since there is no way to set this nonzero (we don't grok the | |
180 | LD_HWCAP_MASK environment variable here), there is no real point in | |
181 | setting _dl_hwcap nonzero below, but we do anyway. */ | |
7c241325 | 182 | uint64_t _dl_hwcap_mask; |
ff08fc59 | 183 | #endif |
7bfa311f | 184 | |
30950a5f RA |
185 | /* Prevailing state of the stack. Generally this includes PF_X, indicating it's |
186 | * executable but this isn't true for all platforms. */ | |
187 | ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS; | |
ecdeaac0 | 188 | |
520a5887 | 189 | #if PTHREAD_IN_LIBC |
1daccf40 FW |
190 | list_t _dl_stack_used; |
191 | list_t _dl_stack_user; | |
9d124d81 FW |
192 | list_t _dl_stack_cache; |
193 | size_t _dl_stack_cache_actsize; | |
194 | uintptr_t _dl_in_flight_stack; | |
1daccf40 FW |
195 | int _dl_stack_cache_lock; |
196 | #else | |
2dd87703 FW |
197 | /* If loading a shared object requires that we make the stack executable |
198 | when it was not, we do it by calling this function. | |
199 | It returns an errno code or zero on success. */ | |
200 | int (*_dl_make_stack_executable_hook) (void **) = _dl_make_stack_executable; | |
7cbf1c84 | 201 | void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls; |
a5df0318 | 202 | #endif |
e4eb675d UD |
203 | struct dl_scope_free_list *_dl_scope_free_list; |
204 | ||
5e289179 | 205 | #ifdef NEED_DL_SYSINFO |
cabc8a29 L |
206 | /* Needed for improved syscall handling on at least x86/Linux. NB: Don't |
207 | initialize it here to avoid RELATIVE relocation in static PIE. */ | |
208 | uintptr_t _dl_sysinfo; | |
30e32d23 | 209 | #endif |
7775448e | 210 | #ifdef NEED_DL_SYSINFO_DSO |
f866314b UD |
211 | /* Address of the ELF headers in the vsyscall page. */ |
212 | const ElfW(Ehdr) *_dl_sysinfo_dso; | |
9cee5585 L |
213 | |
214 | struct link_map *_dl_sysinfo_map; | |
215 | ||
216 | # include "get-dynamic-info.h" | |
5e289179 | 217 | #endif |
d0d4f868 | 218 | #include "setup-vdso.h" |
1bdda52f AZ |
219 | /* Define the vDSO function pointers. */ |
220 | #include <dl-vdso-setup.c> | |
5e289179 | 221 | |
cf197e41 UD |
222 | /* During the program run we must not modify the global data of |
223 | loaded shared object simultanously in two threads. Therefore we | |
224 | protect `_dl_open' and `_dl_close' in dl-close.c. | |
225 | ||
226 | This must be a recursive lock since the initializer function of | |
227 | the loaded object might as well require a call to this function. | |
228 | At this time it is not anymore a problem to modify the tables. */ | |
d3c9f895 | 229 | __rtld_lock_define_initialized_recursive (, _dl_load_lock) |
5a2a1d75 AS |
230 | /* This lock is used to keep __dl_iterate_phdr from inspecting the |
231 | list of loaded objects while an object is added to or removed from | |
232 | that list. */ | |
233 | __rtld_lock_define_initialized_recursive (, _dl_load_write_lock) | |
83b53232 SN |
234 | /* This lock protects global and module specific TLS related data. |
235 | E.g. it is held in dlopen and dlclose when GL(dl_tls_generation), | |
236 | GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are | |
237 | accessed and when TLS related relocations are processed for a | |
238 | module. It was introduced to keep pthread_create accessing TLS | |
239 | state that is being set up. */ | |
240 | __rtld_lock_define_initialized_recursive (, _dl_load_tls_lock) | |
cf197e41 | 241 | |
f8f900ec | 242 | |
e4a5f77d | 243 | #ifdef HAVE_AUX_VECTOR |
73fc4e28 FW |
244 | #include <dl-parse_auxv.h> |
245 | ||
d6b5d570 | 246 | int _dl_clktck; |
0a54e401 | 247 | |
e4a5f77d | 248 | void |
e4a5f77d | 249 | _dl_aux_init (ElfW(auxv_t) *av) |
b13927da | 250 | { |
cabc8a29 L |
251 | #ifdef NEED_DL_SYSINFO |
252 | /* NB: Avoid RELATIVE relocation in static PIE. */ | |
253 | GL(dl_sysinfo) = DL_SYSINFO_DEFAULT; | |
254 | #endif | |
255 | ||
c7683a6d | 256 | _dl_auxv = av; |
73fc4e28 FW |
257 | dl_parse_auxv_t auxv_values; |
258 | /* Use an explicit initialization loop here because memset may not | |
259 | be available yet. */ | |
260 | for (int i = 0; i < array_length (auxv_values); ++i) | |
261 | auxv_values[i] = 0; | |
262 | _dl_parse_auxv (av, auxv_values); | |
e4a5f77d | 263 | } |
155fd00c | 264 | #endif |
f8f900ec | 265 | |
e4a5f77d | 266 | |
d417e0ff | 267 | void |
d417e0ff | 268 | _dl_non_dynamic_init (void) |
e4a5f77d | 269 | { |
f91f1c0f | 270 | _dl_main_map.l_origin = _dl_get_origin (); |
0d23a5c1 MR |
271 | _dl_main_map.l_phdr = GL(dl_phdr); |
272 | _dl_main_map.l_phnum = GL(dl_phnum); | |
f91f1c0f | 273 | |
f8f900ec | 274 | _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1; |
e34b0f29 | 275 | |
9cee5585 L |
276 | /* Set up the data structures for the system-supplied DSO early, |
277 | so they can influence _dl_init_paths. */ | |
278 | setup_vdso (NULL, NULL); | |
279 | ||
1bdda52f AZ |
280 | /* With vDSO setup we can initialize the function pointers. */ |
281 | setup_vdso_pointers (); | |
282 | ||
0a54e401 UD |
283 | /* Initialize the data structures for the search paths for shared |
284 | objects. */ | |
dad90d52 FW |
285 | _dl_init_paths (getenv ("LD_LIBRARY_PATH"), "LD_LIBRARY_PATH", |
286 | /* No glibc-hwcaps selection support in statically | |
287 | linked binaries. */ | |
288 | NULL, NULL); | |
0a54e401 | 289 | |
bc5fb037 AS |
290 | /* Remember the last search directory added at startup. */ |
291 | _dl_init_all_dirs = GL(dl_all_dirs); | |
292 | ||
12b5b6b7 UD |
293 | _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0'; |
294 | ||
f53c03c2 UD |
295 | _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0'; |
296 | ||
dec126b4 UD |
297 | _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0'; |
298 | ||
53bfdc1c UD |
299 | _dl_profile_output = getenv ("LD_PROFILE_OUTPUT"); |
300 | if (_dl_profile_output == NULL || _dl_profile_output[0] == '\0') | |
301 | _dl_profile_output | |
302 | = &"/var/tmp\0/var/profile"[__libc_enable_secure ? 9 : 0]; | |
303 | ||
74955460 UD |
304 | if (__libc_enable_secure) |
305 | { | |
c4e328a1 UD |
306 | static const char unsecure_envvars[] = |
307 | UNSECURE_ENVVARS | |
74955460 UD |
308 | #ifdef EXTRA_UNSECURE_ENVVARS |
309 | EXTRA_UNSECURE_ENVVARS | |
310 | #endif | |
c4e328a1 UD |
311 | ; |
312 | const char *cp = unsecure_envvars; | |
74955460 | 313 | |
c4e328a1 UD |
314 | while (cp < unsecure_envvars + sizeof (unsecure_envvars)) |
315 | { | |
316 | __unsetenv (cp); | |
317 | cp = (const char *) __rawmemchr (cp, '\0') + 1; | |
318 | } | |
74955460 | 319 | |
67e58f39 | 320 | #if !HAVE_TUNABLES |
74955460 | 321 | if (__access ("/etc/suid-debug", F_OK) != 0) |
c4e328a1 | 322 | __unsetenv ("MALLOC_CHECK_"); |
67e58f39 | 323 | #endif |
74955460 UD |
324 | } |
325 | ||
0a54e401 UD |
326 | #ifdef DL_PLATFORM_INIT |
327 | DL_PLATFORM_INIT; | |
328 | #endif | |
329 | ||
2402cdf3 RM |
330 | #ifdef DL_OSVERSION_INIT |
331 | DL_OSVERSION_INIT; | |
332 | #endif | |
333 | ||
0a54e401 UD |
334 | /* Now determine the length of the platform string. */ |
335 | if (_dl_platform != NULL) | |
336 | _dl_platformlen = strlen (_dl_platform); | |
ecdeaac0 | 337 | |
ecdeaac0 | 338 | if (_dl_phdr != NULL) |
57013650 AZ |
339 | for (const ElfW(Phdr) *ph = _dl_phdr; ph < &_dl_phdr[_dl_phnum]; ++ph) |
340 | switch (ph->p_type) | |
ecdeaac0 | 341 | { |
57013650 AZ |
342 | /* Check if the stack is nonexecutable. */ |
343 | case PT_GNU_STACK: | |
344 | _dl_stack_flags = ph->p_flags; | |
345 | break; | |
346 | ||
347 | case PT_GNU_RELRO: | |
348 | _dl_main_map.l_relro_addr = ph->p_vaddr; | |
349 | _dl_main_map.l_relro_size = ph->p_memsz; | |
ecdeaac0 RM |
350 | break; |
351 | } | |
57013650 | 352 | |
5d28a896 FW |
353 | call_function_static_weak (_dl_find_object_init); |
354 | ||
57013650 AZ |
355 | /* Setup relro on the binary itself. */ |
356 | if (_dl_main_map.l_relro_size != 0) | |
357 | _dl_protect_relro (&_dl_main_map); | |
b13927da | 358 | } |
d417e0ff | 359 | |
5e289179 UD |
360 | #ifdef DL_SYSINFO_IMPLEMENTATION |
361 | DL_SYSINFO_IMPLEMENTATION | |
362 | #endif | |
9d7a3741 L |
363 | |
364 | #if ENABLE_STATIC_PIE | |
365 | /* Since relocation to hidden _dl_main_map causes relocation overflow on | |
366 | aarch64, a function is used to get the address of _dl_main_map. */ | |
367 | ||
368 | struct link_map * | |
369 | _dl_get_dl_main_map (void) | |
370 | { | |
371 | return &_dl_main_map; | |
372 | } | |
373 | #endif | |
8c0664e2 AZ |
374 | |
375 | /* This is used by _dl_runtime_profile, not used on static code. */ | |
376 | void | |
377 | DL_ARCH_FIXUP_ATTRIBUTE | |
378 | _dl_audit_pltexit (struct link_map *l, ElfW(Word) reloc_arg, | |
379 | const void *inregs, void *outregs) | |
380 | { | |
381 | } |