]>
Commit | Line | Data |
---|---|---|
d66e34cd | 1 | /* Run time dynamic linker. |
0c5ecdc4 | 2 | Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc. |
afd4eb37 | 3 | This file is part of the GNU C Library. |
d66e34cd | 4 | |
afd4eb37 UD |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Library General Public License as | |
7 | published by the Free Software Foundation; either version 2 of the | |
8 | License, or (at your option) any later version. | |
d66e34cd | 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 | |
13 | Library General Public License for more details. | |
d66e34cd | 14 | |
afd4eb37 UD |
15 | You should have received a copy of the GNU Library General Public |
16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
d66e34cd RM |
19 | |
20 | #include <link.h> | |
d66e34cd RM |
21 | #include <stddef.h> |
22 | #include <stdlib.h> | |
f51d1dfd | 23 | #include <string.h> |
d66e34cd | 24 | #include <unistd.h> |
2064087b | 25 | #include <sys/mman.h> /* Check if MAP_ANON is defined. */ |
ce37fa88 | 26 | #include <stdio-common/_itoa.h> |
b1dbbaa4 | 27 | #include <assert.h> |
f21acc89 | 28 | #include <entry.h> |
f5348425 RM |
29 | #include "dynamic-link.h" |
30 | ||
31 | ||
d66e34cd RM |
32 | /* System-specific function to do initial startup for the dynamic linker. |
33 | After this, file access calls and getenv must work. This is responsible | |
cddcfecf | 34 | for setting __libc_enable_secure if we need to be secure (e.g. setuid), |
d66e34cd | 35 | and for setting _dl_argc and _dl_argv, and then calling _dl_main. */ |
266180eb RM |
36 | extern ElfW(Addr) _dl_sysdep_start (void **start_argptr, |
37 | void (*dl_main) (const ElfW(Phdr) *phdr, | |
38 | ElfW(Half) phent, | |
39 | ElfW(Addr) *user_entry)); | |
4cb20290 | 40 | extern void _dl_sysdep_start_cleanup (void); |
d66e34cd | 41 | |
14bab8de UD |
42 | /* System-dependent function to read a file's whole contents |
43 | in the most convenient manner available. */ | |
44 | extern void *_dl_sysdep_read_whole_file (const char *filename, | |
45 | size_t *filesize_ptr, | |
46 | int mmap_prot); | |
47 | ||
fd26970f | 48 | /* Helper function to handle errors while resolving symbols. */ |
c84142e8 UD |
49 | static void print_unresolved (int errcode, const char *objname, |
50 | const char *errsting); | |
51 | ||
52 | /* Helper function to handle errors when a version is missing. */ | |
53 | static void print_missing_version (int errcode, const char *objname, | |
54 | const char *errsting); | |
fd26970f | 55 | |
d66e34cd RM |
56 | int _dl_argc; |
57 | char **_dl_argv; | |
4cb20290 | 58 | const char *_dl_rpath; |
cf29ffbe | 59 | int _dl_verbose; |
0a54e401 UD |
60 | const char *_dl_platform; |
61 | size_t _dl_platformlen; | |
f41c8091 | 62 | unsigned long _dl_hwcap; |
0a54e401 | 63 | struct r_search_path *_dl_search_paths; |
3996f34b UD |
64 | const char *_dl_profile; |
65 | const char *_dl_profile_output; | |
66 | struct link_map *_dl_profile_map; | |
d66e34cd | 67 | |
39778c6c UD |
68 | /* Set nonzero during loading and initialization of executable and |
69 | libraries, cleared before the executable's entry point runs. This | |
70 | must not be initialized to nonzero, because the unused dynamic | |
71 | linker loaded in for libc.so's "ld.so.1" dep will provide the | |
72 | definition seen by libc.so's initializer; that value must be zero, | |
73 | and will be since that dynamic linker's _dl_start and dl_main will | |
74 | never be called. */ | |
75 | int _dl_starting_up; | |
76 | ||
266180eb RM |
77 | static void dl_main (const ElfW(Phdr) *phdr, |
78 | ElfW(Half) phent, | |
79 | ElfW(Addr) *user_entry); | |
d66e34cd | 80 | |
ee188d55 | 81 | struct link_map _dl_rtld_map; |
c84142e8 | 82 | struct libname_list _dl_rtld_libname; |
f41c8091 | 83 | struct libname_list _dl_rtld_libname2; |
86d2c878 | 84 | |
b1dbbaa4 RM |
85 | #ifdef RTLD_START |
86 | RTLD_START | |
87 | #else | |
88 | #error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START" | |
89 | #endif | |
90 | ||
ceb2d9aa | 91 | static ElfW(Addr) |
d66e34cd RM |
92 | _dl_start (void *arg) |
93 | { | |
86d2c878 | 94 | struct link_map bootstrap_map; |
d66e34cd | 95 | |
b1dbbaa4 RM |
96 | /* This #define produces dynamic linking inline functions for |
97 | bootstrap relocation instead of general-purpose relocation. */ | |
98 | #define RTLD_BOOTSTRAP | |
c84142e8 | 99 | #define RESOLVE(sym, version, flags) bootstrap_map.l_addr |
b1dbbaa4 RM |
100 | #include "dynamic-link.h" |
101 | ||
d66e34cd | 102 | /* Figure out the run-time load address of the dynamic linker itself. */ |
86d2c878 | 103 | bootstrap_map.l_addr = elf_machine_load_address (); |
d66e34cd | 104 | |
47707456 UD |
105 | /* Read our own dynamic section and fill in the info array. */ |
106 | bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic (); | |
86d2c878 | 107 | elf_get_dynamic_info (bootstrap_map.l_ld, bootstrap_map.l_info); |
d66e34cd RM |
108 | |
109 | #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC | |
86d2c878 | 110 | ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map.l_info); |
d66e34cd RM |
111 | #endif |
112 | ||
113 | /* Relocate ourselves so we can do normal function calls and | |
114 | data access using the global offset table. */ | |
421f82e5 | 115 | |
3996f34b | 116 | ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, 0); |
421f82e5 | 117 | |
d66e34cd RM |
118 | /* Now life is sane; we can call functions and access global data. |
119 | Set up to use the operating system facilities, and find out from | |
120 | the operating system's program loader where to find the program | |
121 | header table in core. */ | |
122 | ||
86d2c878 | 123 | /* Transfer data about ourselves to the permanent link_map structure. */ |
ee188d55 RM |
124 | _dl_rtld_map.l_addr = bootstrap_map.l_addr; |
125 | _dl_rtld_map.l_ld = bootstrap_map.l_ld; | |
f41c8091 | 126 | _dl_rtld_map.l_opencount = 1; |
ee188d55 RM |
127 | memcpy (_dl_rtld_map.l_info, bootstrap_map.l_info, |
128 | sizeof _dl_rtld_map.l_info); | |
129 | _dl_setup_hash (&_dl_rtld_map); | |
86d2c878 | 130 | |
4cb20290 RM |
131 | /* Cache the DT_RPATH stored in ld.so itself; this will be |
132 | the default search path. */ | |
f41c8091 UD |
133 | if (_dl_rtld_map.l_info[DT_STRTAB] && _dl_rtld_map.l_info[DT_RPATH]) |
134 | { | |
135 | _dl_rpath = (void *) (_dl_rtld_map.l_addr + | |
136 | _dl_rtld_map.l_info[DT_STRTAB]->d_un.d_ptr + | |
137 | _dl_rtld_map.l_info[DT_RPATH]->d_un.d_val); | |
138 | } | |
d66e34cd RM |
139 | |
140 | /* Call the OS-dependent function to set up life so we can do things like | |
141 | file access. It will call `dl_main' (below) to do all the real work | |
142 | of the dynamic linker, and then unwind our frame and run the user | |
143 | entry point on the same stack we entered on. */ | |
8d6468d0 | 144 | return _dl_sysdep_start (arg, &dl_main); |
d66e34cd RM |
145 | } |
146 | ||
147 | ||
148 | /* Now life is peachy; we can do all normal operations. | |
149 | On to the real work. */ | |
150 | ||
f21acc89 | 151 | void ENTRY_POINT (void); |
d66e34cd | 152 | |
993b3242 UD |
153 | /* Some helper functions. */ |
154 | ||
155 | /* Arguments to relocate_doit. */ | |
156 | struct relocate_args | |
157 | { | |
158 | struct link_map *l; | |
159 | int lazy; | |
160 | }; | |
161 | ||
162 | struct map_args | |
163 | { | |
164 | /* Argument to map_doit. */ | |
165 | char *str; | |
166 | /* Return value of map_doit. */ | |
167 | struct link_map *main_map; | |
168 | }; | |
169 | ||
170 | /* Arguments to version_check_doit. */ | |
171 | struct version_check_args | |
172 | { | |
173 | struct link_map *main_map; | |
174 | int doexit; | |
175 | }; | |
176 | ||
177 | static void | |
178 | relocate_doit (void *a) | |
179 | { | |
180 | struct relocate_args *args = (struct relocate_args *) a; | |
181 | ||
182 | _dl_relocate_object (args->l, _dl_object_relocation_scope (args->l), | |
183 | args->lazy); | |
184 | } | |
185 | ||
186 | static void | |
187 | map_doit (void *a) | |
188 | { | |
189 | struct map_args *args = (struct map_args *)a; | |
190 | args->main_map = _dl_map_object (NULL, args->str, lt_library, 0); | |
191 | } | |
192 | ||
193 | static void | |
194 | version_check_doit (void *a) | |
195 | { | |
196 | struct version_check_args *args = (struct version_check_args *)a; | |
197 | if (_dl_check_all_versions (args->main_map, 1) && args->doexit) | |
198 | /* We cannot start the application. Abort now. */ | |
199 | _exit (1); | |
200 | } | |
201 | ||
ce37fa88 UD |
202 | |
203 | static inline struct link_map * | |
204 | find_needed (const char *name) | |
205 | { | |
206 | unsigned int n; | |
207 | ||
208 | for (n = 0; n < _dl_loaded->l_nsearchlist; ++n) | |
209 | if (_dl_name_match_p (name, _dl_loaded->l_searchlist[n])) | |
210 | return _dl_loaded->l_searchlist[n]; | |
211 | ||
212 | /* Should never happen. */ | |
213 | return NULL; | |
214 | } | |
215 | ||
216 | static int | |
217 | match_version (const char *string, struct link_map *map) | |
218 | { | |
219 | const char *strtab = (const char *) (map->l_addr | |
220 | + map->l_info[DT_STRTAB]->d_un.d_ptr); | |
221 | ElfW(Verdef) *def; | |
222 | ||
223 | #define VERDEFTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (DT_VERDEF)) | |
224 | if (map->l_info[VERDEFTAG] == NULL) | |
225 | /* The file has no symbol versioning. */ | |
226 | return 0; | |
227 | ||
228 | def = (ElfW(Verdef) *) ((char *) map->l_addr | |
229 | + map->l_info[VERDEFTAG]->d_un.d_ptr); | |
230 | while (1) | |
231 | { | |
232 | ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux); | |
233 | ||
234 | /* Compare the version strings. */ | |
235 | if (strcmp (string, strtab + aux->vda_name) == 0) | |
236 | /* Bingo! */ | |
237 | return 1; | |
238 | ||
239 | /* If no more definitions we failed to find what we want. */ | |
240 | if (def->vd_next == 0) | |
241 | break; | |
242 | ||
243 | /* Next definition. */ | |
244 | def = (ElfW(Verdef) *) ((char *) def + def->vd_next); | |
245 | } | |
246 | ||
247 | return 0; | |
248 | } | |
249 | ||
91f62ce6 | 250 | unsigned int _dl_skip_args; /* Nonzero if we were run directly. */ |
a1a9d215 | 251 | |
d66e34cd | 252 | static void |
266180eb RM |
253 | dl_main (const ElfW(Phdr) *phdr, |
254 | ElfW(Half) phent, | |
255 | ElfW(Addr) *user_entry) | |
d66e34cd | 256 | { |
266180eb | 257 | const ElfW(Phdr) *ph; |
ceb2d9aa | 258 | struct link_map *main_map; |
0200214b | 259 | int lazy; |
2de99474 | 260 | enum { normal, list, verify, trace } mode; |
2064087b RM |
261 | struct link_map **preloads; |
262 | unsigned int npreloads; | |
fd26970f | 263 | const char *preloadlist; |
14bab8de UD |
264 | size_t file_size; |
265 | char *file; | |
2f6d1f1b | 266 | int has_interp = 0; |
d66e34cd | 267 | |
ca34d7a7 UD |
268 | /* Test whether we want to see the content of the auxiliary array passed |
269 | up from the kernel. */ | |
270 | if (getenv ("LD_SHOW_AUXV") != NULL) | |
271 | _dl_show_auxv (); | |
272 | ||
2de99474 | 273 | mode = getenv ("LD_TRACE_LOADED_OBJECTS") != NULL ? trace : normal; |
cf29ffbe | 274 | _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1; |
2de99474 | 275 | |
cf29ffbe UD |
276 | /* LAZY is determined by the environment variable LD_WARN and |
277 | LD_BIND_NOW if we trace the binary. */ | |
fd26970f | 278 | if (mode == trace) |
cf29ffbe UD |
279 | lazy = (_dl_verbose |
280 | ? (*(getenv ("LD_BIND_NOW") ?: "") == '\0' ? 1 : 0) : -1); | |
fd26970f UD |
281 | else |
282 | lazy = !__libc_enable_secure && *(getenv ("LD_BIND_NOW") ?: "") == '\0'; | |
283 | ||
3996f34b UD |
284 | /* See whether we want to use profiling. */ |
285 | _dl_profile = getenv ("LD_PROFILE"); | |
286 | if (_dl_profile != NULL) | |
287 | if (_dl_profile[0] == '\0') | |
288 | /* An empty string is of not much help. Disable profiling. */ | |
289 | _dl_profile = NULL; | |
290 | else | |
291 | { | |
292 | /* OK, we have the name of a shared object we want to | |
293 | profile. It's up to the user to provide a good name, it | |
294 | must match the file name or soname of one of the loaded | |
295 | objects. Now let's see where we are supposed to place the | |
296 | result. */ | |
297 | _dl_profile_output = getenv ("LD_PROFILE_OUTPUT"); | |
298 | ||
299 | if (_dl_profile_output == NULL || _dl_profile_output[0] == '\0') | |
300 | /* This is the default place. */ | |
301 | _dl_profile_output = "/var/tmp"; | |
302 | } | |
303 | ||
46ec036d UD |
304 | /* Set up a flag which tells we are just starting. */ |
305 | _dl_starting_up = 1; | |
306 | ||
f21acc89 | 307 | if (*user_entry == (ElfW(Addr)) &ENTRY_POINT) |
0200214b RM |
308 | { |
309 | /* Ho ho. We are not the program interpreter! We are the program | |
310 | itself! This means someone ran ld.so as a command. Well, that | |
311 | might be convenient to do sometimes. We support it by | |
312 | interpreting the args like this: | |
313 | ||
314 | ld.so PROGRAM ARGS... | |
315 | ||
316 | The first argument is the name of a file containing an ELF | |
317 | executable we will load and run with the following arguments. | |
318 | To simplify life here, PROGRAM is searched for using the | |
319 | normal rules for shared objects, rather than $PATH or anything | |
320 | like that. We just load it and use its entry point; we don't | |
321 | pay attention to its PT_INTERP command (we are the interpreter | |
322 | ourselves). This is an easy way to test a new ld.so before | |
323 | installing it. */ | |
421f82e5 | 324 | |
ffee1316 RM |
325 | /* Note the place where the dynamic linker actually came from. */ |
326 | _dl_rtld_map.l_name = _dl_argv[0]; | |
6a76c115 | 327 | |
fd26970f UD |
328 | while (_dl_argc > 1) |
329 | if (! strcmp (_dl_argv[1], "--list")) | |
330 | { | |
331 | mode = list; | |
332 | lazy = -1; /* This means do no dependency analysis. */ | |
61965e9b | 333 | |
fd26970f UD |
334 | ++_dl_skip_args; |
335 | --_dl_argc; | |
336 | ++_dl_argv; | |
337 | } | |
338 | else if (! strcmp (_dl_argv[1], "--verify")) | |
339 | { | |
340 | mode = verify; | |
6a76c115 | 341 | |
fd26970f UD |
342 | ++_dl_skip_args; |
343 | --_dl_argc; | |
344 | ++_dl_argv; | |
345 | } | |
346 | else | |
347 | break; | |
d66e34cd | 348 | |
61eb22d3 UD |
349 | /* If we have no further argument the program was called incorrectly. |
350 | Grant the user some education. */ | |
351 | if (_dl_argc < 2) | |
352 | _dl_sysdep_fatal ("\ | |
353 | Usage: ld.so [--list|--verify] EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\ | |
354 | You have invoked `ld.so', the helper program for shared library executables.\n\ | |
355 | This program usually lives in the file `/lib/ld.so', and special directives\n\ | |
356 | in executable files using ELF shared libraries tell the system's program\n\ | |
357 | loader to load the helper program from this file. This helper program loads\n\ | |
358 | the shared libraries needed by the program executable, prepares the program\n\ | |
359 | to run, and runs it. You may invoke this helper program directly from the\n\ | |
360 | command line to load and run an ELF executable file; this is like executing\n\ | |
361 | that file itself, but always uses this helper program from the file you\n\ | |
362 | specified, instead of the helper program file specified in the executable\n\ | |
363 | file you run. This is mostly of use for maintainers to test new versions\n\ | |
364 | of this helper program; chances are you did not intend to run this program.\n", | |
365 | NULL); | |
366 | ||
0200214b RM |
367 | ++_dl_skip_args; |
368 | --_dl_argc; | |
369 | ++_dl_argv; | |
91f62ce6 | 370 | |
2de99474 UD |
371 | if (mode == verify) |
372 | { | |
dcf0671d | 373 | char *err_str = NULL; |
2de99474 | 374 | const char *obj_name __attribute__ ((unused)); |
993b3242 | 375 | struct map_args args; |
2de99474 | 376 | |
993b3242 UD |
377 | args.str = _dl_argv[0]; |
378 | (void) _dl_catch_error (&err_str, &obj_name, map_doit, &args); | |
379 | main_map = args.main_map; | |
2de99474 | 380 | if (err_str != NULL) |
dcf0671d UD |
381 | { |
382 | free (err_str); | |
383 | _exit (EXIT_FAILURE); | |
384 | } | |
2de99474 UD |
385 | } |
386 | else | |
ceb2d9aa | 387 | main_map = _dl_map_object (NULL, _dl_argv[0], lt_library, 0); |
2de99474 | 388 | |
ceb2d9aa UD |
389 | phdr = main_map->l_phdr; |
390 | phent = main_map->l_phnum; | |
391 | main_map->l_name = (char *) ""; | |
392 | *user_entry = main_map->l_entry; | |
0200214b RM |
393 | } |
394 | else | |
395 | { | |
396 | /* Create a link_map for the executable itself. | |
397 | This will be what dlopen on "" returns. */ | |
f2ea0f5b UD |
398 | main_map = _dl_new_object (_dl_argv[0] ?: (char *) "<main program>", |
399 | "", lt_executable); | |
ceb2d9aa | 400 | if (main_map == NULL) |
762a2918 | 401 | _dl_sysdep_fatal ("cannot allocate memory for link map\n", NULL); |
ceb2d9aa UD |
402 | main_map->l_phdr = phdr; |
403 | main_map->l_phnum = phent; | |
404 | main_map->l_entry = *user_entry; | |
3e5f5557 | 405 | main_map->l_opencount = 1; |
0200214b RM |
406 | } |
407 | ||
408 | /* Scan the program header table for the dynamic section. */ | |
409 | for (ph = phdr; ph < &phdr[phent]; ++ph) | |
410 | switch (ph->p_type) | |
411 | { | |
412 | case PT_DYNAMIC: | |
413 | /* This tells us where to find the dynamic section, | |
414 | which tells us everything we need to do. */ | |
ceb2d9aa | 415 | main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr; |
0200214b RM |
416 | break; |
417 | case PT_INTERP: | |
418 | /* This "interpreter segment" was used by the program loader to | |
419 | find the program interpreter, which is this program itself, the | |
420 | dynamic linker. We note what name finds us, so that a future | |
421 | dlopen call or DT_NEEDED entry, for something that wants to link | |
422 | against the dynamic linker as a shared library, will know that | |
423 | the shared object is already loaded. */ | |
ceb2d9aa | 424 | _dl_rtld_libname.name = (const char *) main_map->l_addr + ph->p_vaddr; |
c84142e8 UD |
425 | _dl_rtld_libname.next = NULL; |
426 | _dl_rtld_map.l_libname = &_dl_rtld_libname; | |
f41c8091 UD |
427 | |
428 | /* Ordinarilly, we would get additional names for the loader from | |
429 | our DT_SONAME. This can't happen if we were actually linked as | |
430 | a static executable (detect this case when we have no DYNAMIC). | |
431 | If so, assume the filename component of the interpreter path to | |
432 | be our SONAME, and add it to our name list. */ | |
433 | if (_dl_rtld_map.l_ld == NULL) | |
434 | { | |
435 | char *p = strrchr (_dl_rtld_libname.name, '/'); | |
436 | if (p) | |
437 | { | |
438 | _dl_rtld_libname2.name = p+1; | |
439 | _dl_rtld_libname2.next = NULL; | |
440 | _dl_rtld_libname.next = &_dl_rtld_libname2; | |
441 | } | |
442 | } | |
443 | ||
2f6d1f1b | 444 | has_interp = 1; |
0200214b RM |
445 | break; |
446 | } | |
ffee1316 | 447 | if (! _dl_rtld_map.l_libname && _dl_rtld_map.l_name) |
c84142e8 UD |
448 | { |
449 | /* We were invoked directly, so the program might not have a | |
450 | PT_INTERP. */ | |
451 | _dl_rtld_libname.name = _dl_rtld_map.l_name; | |
452 | _dl_rtld_libname.next = NULL; | |
453 | _dl_rtld_map.l_libname = &_dl_rtld_libname; | |
454 | } | |
ffee1316 RM |
455 | else |
456 | assert (_dl_rtld_map.l_libname); /* How else did we get here? */ | |
0200214b | 457 | |
61965e9b RM |
458 | if (mode == verify) |
459 | /* We were called just to verify that this is a dynamic executable | |
460 | using us as the program interpreter. */ | |
ceb2d9aa | 461 | _exit (main_map->l_ld == NULL ? 1 : has_interp ? 0 : 2); |
61965e9b | 462 | |
0200214b | 463 | /* Extract the contents of the dynamic section for easy access. */ |
ceb2d9aa UD |
464 | elf_get_dynamic_info (main_map->l_ld, main_map->l_info); |
465 | if (main_map->l_info[DT_HASH]) | |
0200214b | 466 | /* Set up our cache of pointers into the hash table. */ |
ceb2d9aa | 467 | _dl_setup_hash (main_map); |
0200214b | 468 | |
0200214b | 469 | /* Put the link_map for ourselves on the chain so it can be found by |
ceb2d9aa UD |
470 | name. Note that at this point the global chain of link maps contains |
471 | exactly one element, which is pointed to by main_map. */ | |
ffee1316 RM |
472 | if (! _dl_rtld_map.l_name) |
473 | /* If not invoked directly, the dynamic linker shared object file was | |
474 | found by the PT_INTERP name. */ | |
c84142e8 | 475 | _dl_rtld_map.l_name = (char *) _dl_rtld_map.l_libname->name; |
ba79d61b | 476 | _dl_rtld_map.l_type = lt_library; |
ceb2d9aa UD |
477 | main_map->l_next = &_dl_rtld_map; |
478 | _dl_rtld_map.l_prev = main_map; | |
0200214b | 479 | |
14bab8de UD |
480 | /* We have two ways to specify objects to preload: via environment |
481 | variable and via the file /etc/ld.so.preload. The later can also | |
482 | be used when security is enabled. */ | |
2064087b RM |
483 | preloads = NULL; |
484 | npreloads = 0; | |
14bab8de | 485 | |
fd26970f UD |
486 | preloadlist = getenv ("LD_PRELOAD"); |
487 | if (preloadlist) | |
c4029823 | 488 | { |
fd26970f UD |
489 | /* The LD_PRELOAD environment variable gives a white space |
490 | separated list of libraries that are loaded before the | |
491 | executable's dependencies and prepended to the global scope | |
492 | list. If the binary is running setuid all elements | |
493 | containing a '/' are ignored since it is insecure. */ | |
494 | char *list = strdupa (preloadlist); | |
495 | char *p; | |
496 | while ((p = strsep (&list, " ")) != NULL) | |
497 | if (! __libc_enable_secure || strchr (p, '/') == NULL) | |
498 | { | |
499 | (void) _dl_map_object (NULL, p, lt_library, 0); | |
500 | ++npreloads; | |
501 | } | |
c4029823 UD |
502 | } |
503 | ||
14bab8de UD |
504 | /* Read the contents of the file. */ |
505 | file = _dl_sysdep_read_whole_file ("/etc/ld.so.preload", &file_size, | |
506 | PROT_READ | PROT_WRITE); | |
507 | if (file) | |
508 | { | |
509 | /* Parse the file. It contains names of libraries to be loaded, | |
510 | separated by white spaces or `:'. It may also contain | |
511 | comments introduced by `#'. */ | |
512 | char *problem; | |
513 | char *runp; | |
514 | size_t rest; | |
515 | ||
516 | /* Eliminate comments. */ | |
517 | runp = file; | |
518 | rest = file_size; | |
519 | while (rest > 0) | |
520 | { | |
521 | char *comment = memchr (runp, '#', rest); | |
522 | if (comment == NULL) | |
523 | break; | |
524 | ||
525 | rest -= comment - runp; | |
526 | do | |
527 | *comment = ' '; | |
528 | while (--rest > 0 && *++comment != '\n'); | |
529 | } | |
530 | ||
531 | /* We have one problematic case: if we have a name at the end of | |
532 | the file without a trailing terminating characters, we cannot | |
533 | place the \0. Handle the case separately. */ | |
534 | if (file[file_size - 1] != ' ' && file[file_size] != '\t' | |
535 | && file[file_size] != '\n') | |
536 | { | |
537 | problem = &file[file_size]; | |
538 | while (problem > file && problem[-1] != ' ' && problem[-1] != '\t' | |
539 | && problem[-1] != '\n') | |
540 | --problem; | |
541 | ||
542 | if (problem > file) | |
543 | problem[-1] = '\0'; | |
544 | } | |
545 | else | |
546 | problem = NULL; | |
547 | ||
548 | if (file != problem) | |
549 | { | |
550 | char *p; | |
551 | runp = file; | |
552 | while ((p = strsep (&runp, ": \t\n")) != NULL) | |
553 | { | |
46ec036d | 554 | (void) _dl_map_object (NULL, p, lt_library, 0); |
14bab8de UD |
555 | ++npreloads; |
556 | } | |
557 | } | |
558 | ||
559 | if (problem != NULL) | |
560 | { | |
561 | char *p = strndupa (problem, file_size - (problem - file)); | |
46ec036d | 562 | (void) _dl_map_object (NULL, p, lt_library, 0); |
14bab8de UD |
563 | } |
564 | ||
565 | /* We don't need the file anymore. */ | |
566 | __munmap (file, file_size); | |
567 | } | |
568 | ||
14bab8de UD |
569 | if (npreloads != 0) |
570 | { | |
571 | /* Set up PRELOADS with a vector of the preloaded libraries. */ | |
572 | struct link_map *l; | |
573 | unsigned int i; | |
574 | preloads = __alloca (npreloads * sizeof preloads[0]); | |
575 | l = _dl_rtld_map.l_next; /* End of the chain before preloads. */ | |
576 | i = 0; | |
577 | do | |
578 | { | |
579 | preloads[i++] = l; | |
580 | l = l->l_next; | |
581 | } while (l); | |
582 | assert (i == npreloads); | |
583 | } | |
584 | ||
0a54e401 UD |
585 | /* Initialize the data structures for the search paths for shared |
586 | objects. */ | |
587 | _dl_init_paths (); | |
588 | ||
2064087b RM |
589 | /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD |
590 | specified some libraries to load, these are inserted before the actual | |
591 | dependencies in the executable's searchlist for symbol resolution. */ | |
ceb2d9aa | 592 | _dl_map_object_deps (main_map, preloads, npreloads, mode == trace); |
d66e34cd | 593 | |
2064087b | 594 | #ifndef MAP_ANON |
f332db02 RM |
595 | /* We are done mapping things, so close the zero-fill descriptor. */ |
596 | __close (_dl_zerofd); | |
597 | _dl_zerofd = -1; | |
2064087b | 598 | #endif |
f332db02 | 599 | |
f9496a7b RM |
600 | /* Remove _dl_rtld_map from the chain. */ |
601 | _dl_rtld_map.l_prev->l_next = _dl_rtld_map.l_next; | |
602 | if (_dl_rtld_map.l_next) | |
603 | _dl_rtld_map.l_next->l_prev = _dl_rtld_map.l_prev; | |
604 | ||
605 | if (_dl_rtld_map.l_opencount) | |
0200214b | 606 | { |
f9496a7b RM |
607 | /* Some DT_NEEDED entry referred to the interpreter object itself, so |
608 | put it back in the list of visible objects. We insert it into the | |
609 | chain in symbol search order because gdb uses the chain's order as | |
610 | its symbol search order. */ | |
611 | unsigned int i = 1; | |
ceb2d9aa | 612 | while (main_map->l_searchlist[i] != &_dl_rtld_map) |
f9496a7b | 613 | ++i; |
ceb2d9aa UD |
614 | _dl_rtld_map.l_prev = main_map->l_searchlist[i - 1]; |
615 | _dl_rtld_map.l_next = (i + 1 < main_map->l_nsearchlist ? | |
616 | main_map->l_searchlist[i + 1] : NULL); | |
f9496a7b RM |
617 | assert (_dl_rtld_map.l_prev->l_next == _dl_rtld_map.l_next); |
618 | _dl_rtld_map.l_prev->l_next = &_dl_rtld_map; | |
4d02a5b1 | 619 | if (_dl_rtld_map.l_next) |
f9496a7b RM |
620 | { |
621 | assert (_dl_rtld_map.l_next->l_prev == _dl_rtld_map.l_prev); | |
622 | _dl_rtld_map.l_next->l_prev = &_dl_rtld_map; | |
623 | } | |
0200214b | 624 | } |
d66e34cd | 625 | |
c84142e8 UD |
626 | /* Now let us see whether all libraries are available in the |
627 | versions we need. */ | |
628 | { | |
993b3242 UD |
629 | struct version_check_args args; |
630 | args.doexit = mode == normal; | |
631 | args.main_map = main_map; | |
632 | _dl_receive_error (print_missing_version, version_check_doit, &args); | |
c84142e8 UD |
633 | } |
634 | ||
2de99474 | 635 | if (mode != normal) |
0200214b RM |
636 | { |
637 | /* We were run just to list the shared libraries. It is | |
638 | important that we do this before real relocation, because the | |
639 | functions we call below for output may no longer work properly | |
640 | after relocation. */ | |
1a3a58fd | 641 | |
0200214b | 642 | int i; |
fd861379 | 643 | |
0200214b RM |
644 | if (! _dl_loaded->l_info[DT_NEEDED]) |
645 | _dl_sysdep_message ("\t", "statically linked\n", NULL); | |
646 | else | |
ceb2d9aa UD |
647 | { |
648 | struct link_map *l; | |
649 | ||
650 | for (l = _dl_loaded->l_next; l; l = l->l_next) | |
651 | if (l->l_opencount == 0) | |
652 | /* The library was not found. */ | |
653 | _dl_sysdep_message ("\t", l->l_libname->name, " => not found\n", | |
654 | NULL); | |
655 | else | |
656 | { | |
657 | char buf[20], *bp; | |
658 | buf[sizeof buf - 1] = '\0'; | |
659 | bp = _itoa (l->l_addr, &buf[sizeof buf - 1], 16, 0); | |
660 | while ((size_t) (&buf[sizeof buf - 1] - bp) | |
661 | < sizeof l->l_addr * 2) | |
662 | *--bp = '0'; | |
663 | _dl_sysdep_message ("\t", l->l_libname->name, " => ", | |
664 | l->l_name, " (0x", bp, ")\n", NULL); | |
665 | } | |
666 | } | |
1a3a58fd | 667 | |
2de99474 | 668 | if (mode != trace) |
cddcfecf RM |
669 | for (i = 1; i < _dl_argc; ++i) |
670 | { | |
671 | const ElfW(Sym) *ref = NULL; | |
672 | ElfW(Addr) loadbase = _dl_lookup_symbol (_dl_argv[i], &ref, | |
673 | &_dl_default_scope[2], | |
dcf0671d | 674 | "argument", |
a2b08ee5 | 675 | ELF_MACHINE_JMP_SLOT); |
cddcfecf RM |
676 | char buf[20], *bp; |
677 | buf[sizeof buf - 1] = '\0'; | |
678 | bp = _itoa (ref->st_value, &buf[sizeof buf - 1], 16, 0); | |
14bab8de | 679 | while ((size_t) (&buf[sizeof buf - 1] - bp) < sizeof loadbase * 2) |
cddcfecf RM |
680 | *--bp = '0'; |
681 | _dl_sysdep_message (_dl_argv[i], " found at 0x", bp, NULL); | |
682 | buf[sizeof buf - 1] = '\0'; | |
683 | bp = _itoa (loadbase, &buf[sizeof buf - 1], 16, 0); | |
14bab8de | 684 | while ((size_t) (&buf[sizeof buf - 1] - bp) < sizeof loadbase * 2) |
cddcfecf RM |
685 | *--bp = '0'; |
686 | _dl_sysdep_message (" in object at 0x", bp, "\n", NULL); | |
687 | } | |
ce37fa88 | 688 | else |
fd26970f | 689 | { |
ce37fa88 UD |
690 | if (lazy >= 0) |
691 | { | |
692 | /* We have to do symbol dependency testing. */ | |
693 | struct relocate_args args; | |
694 | struct link_map *l; | |
993b3242 | 695 | |
ce37fa88 | 696 | args.lazy = lazy; |
fd26970f | 697 | |
ce37fa88 UD |
698 | l = _dl_loaded; |
699 | while (l->l_next) | |
700 | l = l->l_next; | |
701 | do | |
702 | { | |
703 | if (l != &_dl_rtld_map && l->l_opencount > 0) | |
704 | { | |
705 | args.l = l; | |
706 | _dl_receive_error (print_unresolved, relocate_doit, | |
707 | &args); | |
708 | *_dl_global_scope_end = NULL; | |
709 | } | |
710 | l = l->l_prev; | |
711 | } while (l); | |
712 | } | |
713 | ||
714 | #define VERNEEDTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (DT_VERNEED)) | |
715 | if (*(getenv ("LD_VERBOSE") ?: "") != '\0') | |
fd26970f | 716 | { |
ce37fa88 UD |
717 | /* Print more information. This means here, print information |
718 | about the versions needed. */ | |
719 | int first = 1; | |
720 | struct link_map *map = _dl_loaded; | |
721 | ||
722 | for (map = _dl_loaded; map != NULL; map = map->l_next) | |
fd26970f | 723 | { |
f41c8091 | 724 | const char *strtab; |
ce37fa88 | 725 | ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG]; |
f41c8091 UD |
726 | ElfW(Verneed) *ent; |
727 | ||
728 | if (dyn == NULL) | |
729 | continue; | |
730 | ||
731 | strtab = (const char *) | |
732 | (map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr); | |
733 | ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr); | |
ce37fa88 | 734 | |
f41c8091 | 735 | if (first) |
ce37fa88 | 736 | { |
f41c8091 UD |
737 | _dl_sysdep_message ("\n\tVersion information:\n", NULL); |
738 | first = 0; | |
739 | } | |
ce37fa88 | 740 | |
f41c8091 UD |
741 | _dl_sysdep_message ("\t", (map->l_name[0] |
742 | ? map->l_name : _dl_argv[0]), | |
743 | ":\n", NULL); | |
744 | ||
745 | while (1) | |
746 | { | |
747 | ElfW(Vernaux) *aux; | |
748 | struct link_map *needed; | |
ce37fa88 | 749 | |
f41c8091 UD |
750 | needed = find_needed (strtab + ent->vn_file); |
751 | aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux); | |
ce37fa88 UD |
752 | |
753 | while (1) | |
754 | { | |
f41c8091 UD |
755 | const char *fname = NULL; |
756 | ||
757 | _dl_sysdep_message ("\t\t", | |
758 | strtab + ent->vn_file, | |
759 | " (", strtab + aux->vna_name, | |
760 | ") ", | |
761 | (aux->vna_flags | |
762 | & VER_FLG_WEAK | |
763 | ? "[WEAK] " : ""), | |
764 | "=> ", NULL); | |
765 | ||
766 | if (needed != NULL | |
767 | && match_version (strtab+aux->vna_name, needed)) | |
768 | fname = needed->l_name; | |
769 | ||
770 | _dl_sysdep_message (fname ?: "not found", "\n", | |
771 | NULL); | |
ce37fa88 | 772 | |
f41c8091 UD |
773 | if (aux->vna_next == 0) |
774 | /* No more symbols. */ | |
ce37fa88 UD |
775 | break; |
776 | ||
f41c8091 UD |
777 | /* Next symbol. */ |
778 | aux = (ElfW(Vernaux) *) ((char *) aux | |
779 | + aux->vna_next); | |
ce37fa88 | 780 | } |
f41c8091 UD |
781 | |
782 | if (ent->vn_next == 0) | |
783 | /* No more dependencies. */ | |
784 | break; | |
785 | ||
786 | /* Next dependency. */ | |
787 | ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next); | |
ce37fa88 | 788 | } |
fd26970f | 789 | } |
ce37fa88 | 790 | } |
fd26970f | 791 | } |
d66e34cd | 792 | |
0200214b RM |
793 | _exit (0); |
794 | } | |
86d2c878 | 795 | |
ba79d61b RM |
796 | { |
797 | /* Now we have all the objects loaded. Relocate them all except for | |
798 | the dynamic linker itself. We do this in reverse order so that copy | |
799 | relocs of earlier objects overwrite the data written by later | |
800 | objects. We do not re-relocate the dynamic linker itself in this | |
801 | loop because that could result in the GOT entries for functions we | |
802 | call being changed, and that would break us. It is safe to relocate | |
803 | the dynamic linker out of order because it has no copy relocs (we | |
804 | know that because it is self-contained). */ | |
805 | ||
ceb2d9aa | 806 | struct link_map *l; |
ba79d61b RM |
807 | l = _dl_loaded; |
808 | while (l->l_next) | |
809 | l = l->l_next; | |
810 | do | |
811 | { | |
812 | if (l != &_dl_rtld_map) | |
813 | { | |
814 | _dl_relocate_object (l, _dl_object_relocation_scope (l), lazy); | |
815 | *_dl_global_scope_end = NULL; | |
816 | } | |
817 | l = l->l_prev; | |
818 | } while (l); | |
819 | ||
820 | /* Do any necessary cleanups for the startup OS interface code. | |
821 | We do these now so that no calls are made after rtld re-relocation | |
822 | which might be resolved to different functions than we expect. | |
823 | We cannot do this before relocating the other objects because | |
824 | _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */ | |
825 | _dl_sysdep_start_cleanup (); | |
826 | ||
827 | if (_dl_rtld_map.l_opencount > 0) | |
828 | /* There was an explicit ref to the dynamic linker as a shared lib. | |
829 | Re-relocate ourselves with user-controlled symbol definitions. */ | |
830 | _dl_relocate_object (&_dl_rtld_map, &_dl_default_scope[2], 0); | |
831 | } | |
0200214b | 832 | |
4d6acc61 RM |
833 | { |
834 | /* Initialize _r_debug. */ | |
835 | struct r_debug *r = _dl_debug_initialize (_dl_rtld_map.l_addr); | |
ceb2d9aa | 836 | struct link_map *l; |
4d6acc61 RM |
837 | |
838 | l = _dl_loaded; | |
ec42724d RM |
839 | |
840 | #ifdef ELF_MACHINE_DEBUG_SETUP | |
841 | ||
842 | /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */ | |
843 | ||
844 | ELF_MACHINE_DEBUG_SETUP (l, r); | |
845 | ELF_MACHINE_DEBUG_SETUP (&_dl_rtld_map, r); | |
846 | ||
847 | #else | |
848 | ||
4d6acc61 RM |
849 | if (l->l_info[DT_DEBUG]) |
850 | /* There is a DT_DEBUG entry in the dynamic section. Fill it in | |
851 | with the run-time address of the r_debug structure */ | |
852 | l->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r; | |
853 | ||
d746b89c RM |
854 | /* Fill in the pointer in the dynamic linker's own dynamic section, in |
855 | case you run gdb on the dynamic linker directly. */ | |
856 | if (_dl_rtld_map.l_info[DT_DEBUG]) | |
857 | _dl_rtld_map.l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r; | |
858 | ||
ec42724d RM |
859 | #endif |
860 | ||
4d6acc61 RM |
861 | /* Notify the debugger that all objects are now mapped in. */ |
862 | r->r_state = RT_ADD; | |
863 | _dl_debug_state (); | |
864 | } | |
0200214b | 865 | |
3996f34b UD |
866 | /* Now enable profiling if needed. */ |
867 | if (_dl_profile_map != NULL) | |
868 | /* We must prepare the profiling. */ | |
869 | _dl_start_profile (_dl_profile_map, _dl_profile_output); | |
870 | ||
d66e34cd RM |
871 | /* Once we return, _dl_sysdep_start will invoke |
872 | the DT_INIT functions and then *USER_ENTRY. */ | |
873 | } | |
fd26970f UD |
874 | \f |
875 | /* This is a little helper function for resolving symbols while | |
876 | tracing the binary. */ | |
877 | static void | |
c84142e8 UD |
878 | print_unresolved (int errcode __attribute__ ((unused)), const char *objname, |
879 | const char *errstring) | |
fd26970f | 880 | { |
3996f34b UD |
881 | if (objname[0] == '\0') |
882 | objname = _dl_argv[0] ?: "<main program>"; | |
fd26970f UD |
883 | _dl_sysdep_error (errstring, " (", objname, ")\n", NULL); |
884 | } | |
c84142e8 UD |
885 | \f |
886 | /* This is a little helper function for resolving symbols while | |
887 | tracing the binary. */ | |
888 | static void | |
889 | print_missing_version (int errcode __attribute__ ((unused)), | |
890 | const char *objname, const char *errstring) | |
891 | { | |
892 | _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>", ": ", | |
893 | objname, ": ", errstring, "\n", NULL); | |
894 | } |