]>
Commit | Line | Data |
---|---|---|
1 | /* Support for dynamic linking code in static libc. | |
2 | Copyright (C) 1996-2019 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
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. | |
9 | ||
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 | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
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 | ||
22 | #include <errno.h> | |
23 | #include <libintl.h> | |
24 | #include <stdlib.h> | |
25 | #include <unistd.h> | |
26 | #include <sys/param.h> | |
27 | #include <stdint.h> | |
28 | #include <ldsodefs.h> | |
29 | #include <dl-machine.h> | |
30 | #include <libc-lock.h> | |
31 | #include <dl-cache.h> | |
32 | #include <dl-librecon.h> | |
33 | #include <dl-procinfo.h> | |
34 | #include <unsecvars.h> | |
35 | #include <hp-timing.h> | |
36 | #include <stackinfo.h> | |
37 | ||
38 | extern char *__progname; | |
39 | char **_dl_argv = &__progname; /* This is checked for some error messages. */ | |
40 | ||
41 | /* Name of the architecture. */ | |
42 | const char *_dl_platform; | |
43 | size_t _dl_platformlen; | |
44 | ||
45 | int _dl_debug_mask; | |
46 | int _dl_lazy; | |
47 | ElfW(Addr) _dl_use_load_bias = -2; | |
48 | int _dl_dynamic_weak; | |
49 | ||
50 | /* If nonzero print warnings about problematic situations. */ | |
51 | int _dl_verbose; | |
52 | ||
53 | /* We never do profiling. */ | |
54 | const char *_dl_profile; | |
55 | const char *_dl_profile_output; | |
56 | ||
57 | /* Names of shared object for which the RUNPATHs and RPATHs should be | |
58 | ignored. */ | |
59 | const char *_dl_inhibit_rpath; | |
60 | ||
61 | /* The map for the object we will profile. */ | |
62 | struct link_map *_dl_profile_map; | |
63 | ||
64 | /* This is the address of the last stack address ever used. */ | |
65 | void *__libc_stack_end; | |
66 | ||
67 | /* Path where the binary is found. */ | |
68 | const char *_dl_origin_path; | |
69 | ||
70 | /* Nonzero if runtime lookup should not update the .got/.plt. */ | |
71 | int _dl_bind_not; | |
72 | ||
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 | ||
98 | /* Namespace information. */ | |
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; | |
109 | ||
110 | /* Incremented whenever something may have been added to dl_loaded. */ | |
111 | unsigned long long _dl_load_adds = 1; | |
112 | ||
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 | }; | |
119 | ||
120 | #ifndef HAVE_INLINED_SYSCALLS | |
121 | /* Nonzero during startup. */ | |
122 | int _dl_starting_up = 1; | |
123 | #endif | |
124 | ||
125 | /* Random data provided by the kernel. */ | |
126 | void *_dl_random; | |
127 | ||
128 | /* Get architecture specific initializer. */ | |
129 | #include <dl-procruntime.c> | |
130 | #include <dl-procinfo.c> | |
131 | ||
132 | void (*_dl_init_static_tls) (struct link_map *) = &_dl_nothread_init_static_tls; | |
133 | ||
134 | size_t _dl_pagesize = EXEC_PAGESIZE; | |
135 | ||
136 | int _dl_inhibit_cache; | |
137 | ||
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 | ||
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 | ||
154 | ElfW(auxv_t) *_dl_auxv; | |
155 | const ElfW(Phdr) *_dl_phdr; | |
156 | size_t _dl_phnum; | |
157 | uint64_t _dl_hwcap __attribute__ ((nocommon)); | |
158 | uint64_t _dl_hwcap2 __attribute__ ((nocommon)); | |
159 | ||
160 | /* The value of the FPU control word the kernel will preset in hardware. */ | |
161 | fpu_control_t _dl_fpu_control = _FPU_DEFAULT; | |
162 | ||
163 | #if !HAVE_TUNABLES | |
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)); | |
171 | #endif | |
172 | ||
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; | |
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. */ | |
180 | int (*_dl_make_stack_executable_hook) (void **) = _dl_make_stack_executable; | |
181 | ||
182 | ||
183 | /* Function in libpthread to wait for termination of lookups. */ | |
184 | void (*_dl_wait_lookup_done) (void); | |
185 | ||
186 | #if !THREAD_GSCOPE_IN_TCB | |
187 | int _dl_thread_gscope_count; | |
188 | #endif | |
189 | struct dl_scope_free_list *_dl_scope_free_list; | |
190 | ||
191 | #ifdef NEED_DL_SYSINFO | |
192 | /* Needed for improved syscall handling on at least x86/Linux. */ | |
193 | uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT; | |
194 | #endif | |
195 | #ifdef NEED_DL_SYSINFO_DSO | |
196 | /* Address of the ELF headers in the vsyscall page. */ | |
197 | const ElfW(Ehdr) *_dl_sysinfo_dso; | |
198 | ||
199 | struct link_map *_dl_sysinfo_map; | |
200 | ||
201 | # include "get-dynamic-info.h" | |
202 | #endif | |
203 | #include "setup-vdso.h" | |
204 | ||
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. */ | |
212 | __rtld_lock_define_initialized_recursive (, _dl_load_lock) | |
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) | |
217 | ||
218 | ||
219 | #ifdef HAVE_AUX_VECTOR | |
220 | int _dl_clktck; | |
221 | ||
222 | void | |
223 | _dl_aux_init (ElfW(auxv_t) *av) | |
224 | { | |
225 | int seen = 0; | |
226 | uid_t uid = 0; | |
227 | gid_t gid = 0; | |
228 | ||
229 | _dl_auxv = av; | |
230 | for (; av->a_type != AT_NULL; ++av) | |
231 | switch (av->a_type) | |
232 | { | |
233 | case AT_PAGESZ: | |
234 | if (av->a_un.a_val != 0) | |
235 | GLRO(dl_pagesize) = av->a_un.a_val; | |
236 | break; | |
237 | case AT_CLKTCK: | |
238 | GLRO(dl_clktck) = av->a_un.a_val; | |
239 | break; | |
240 | case AT_PHDR: | |
241 | GL(dl_phdr) = (const void *) av->a_un.a_val; | |
242 | break; | |
243 | case AT_PHNUM: | |
244 | GL(dl_phnum) = av->a_un.a_val; | |
245 | break; | |
246 | case AT_PLATFORM: | |
247 | GLRO(dl_platform) = (void *) av->a_un.a_val; | |
248 | break; | |
249 | case AT_HWCAP: | |
250 | GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; | |
251 | break; | |
252 | case AT_HWCAP2: | |
253 | GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val; | |
254 | break; | |
255 | case AT_FPUCW: | |
256 | GLRO(dl_fpu_control) = av->a_un.a_val; | |
257 | break; | |
258 | #ifdef NEED_DL_SYSINFO | |
259 | case AT_SYSINFO: | |
260 | GL(dl_sysinfo) = av->a_un.a_val; | |
261 | break; | |
262 | #endif | |
263 | #ifdef NEED_DL_SYSINFO_DSO | |
264 | case AT_SYSINFO_EHDR: | |
265 | GL(dl_sysinfo_dso) = (void *) av->a_un.a_val; | |
266 | break; | |
267 | #endif | |
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; | |
284 | case AT_SECURE: | |
285 | seen = -1; | |
286 | __libc_enable_secure = av->a_un.a_val; | |
287 | __libc_enable_secure_decided = 1; | |
288 | break; | |
289 | case AT_RANDOM: | |
290 | _dl_random = (void *) av->a_un.a_val; | |
291 | break; | |
292 | # ifdef DL_PLATFORM_AUXV | |
293 | DL_PLATFORM_AUXV | |
294 | # endif | |
295 | } | |
296 | if (seen == 0xf) | |
297 | { | |
298 | __libc_enable_secure = uid != 0 || gid != 0; | |
299 | __libc_enable_secure_decided = 1; | |
300 | } | |
301 | } | |
302 | #endif | |
303 | ||
304 | ||
305 | void | |
306 | _dl_non_dynamic_init (void) | |
307 | { | |
308 | _dl_main_map.l_origin = _dl_get_origin (); | |
309 | _dl_main_map.l_phdr = GL(dl_phdr); | |
310 | _dl_main_map.l_phnum = GL(dl_phnum); | |
311 | ||
312 | _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1; | |
313 | ||
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 | ||
318 | /* Initialize the data structures for the search paths for shared | |
319 | objects. */ | |
320 | _dl_init_paths (getenv ("LD_LIBRARY_PATH")); | |
321 | ||
322 | /* Remember the last search directory added at startup. */ | |
323 | _dl_init_all_dirs = GL(dl_all_dirs); | |
324 | ||
325 | _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0'; | |
326 | ||
327 | _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0'; | |
328 | ||
329 | _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0'; | |
330 | ||
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 | ||
336 | if (__libc_enable_secure) | |
337 | { | |
338 | static const char unsecure_envvars[] = | |
339 | UNSECURE_ENVVARS | |
340 | #ifdef EXTRA_UNSECURE_ENVVARS | |
341 | EXTRA_UNSECURE_ENVVARS | |
342 | #endif | |
343 | ; | |
344 | const char *cp = unsecure_envvars; | |
345 | ||
346 | while (cp < unsecure_envvars + sizeof (unsecure_envvars)) | |
347 | { | |
348 | __unsetenv (cp); | |
349 | cp = (const char *) __rawmemchr (cp, '\0') + 1; | |
350 | } | |
351 | ||
352 | #if !HAVE_TUNABLES | |
353 | if (__access ("/etc/suid-debug", F_OK) != 0) | |
354 | __unsetenv ("MALLOC_CHECK_"); | |
355 | #endif | |
356 | } | |
357 | ||
358 | #ifdef DL_PLATFORM_INIT | |
359 | DL_PLATFORM_INIT; | |
360 | #endif | |
361 | ||
362 | #ifdef DL_OSVERSION_INIT | |
363 | DL_OSVERSION_INIT; | |
364 | #endif | |
365 | ||
366 | /* Now determine the length of the platform string. */ | |
367 | if (_dl_platform != NULL) | |
368 | _dl_platformlen = strlen (_dl_platform); | |
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 | } | |
378 | } | |
379 | ||
380 | #ifdef DL_SYSINFO_IMPLEMENTATION | |
381 | DL_SYSINFO_IMPLEMENTATION | |
382 | #endif | |
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 |