ldso.c 28 KB

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  1. /* vi: set sw=4 ts=4: */
  2. /*
  3. * Program to load an ELF binary on a linux system, and run it
  4. * after resolving ELF shared library symbols
  5. *
  6. * Copyright (C) 2005 by Joakim Tjernlund
  7. * Copyright (C) 2000-2004 by Erik Andersen <andersen@codepoet.org>
  8. * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
  9. * David Engel, Hongjiu Lu and Mitch D'Souza
  10. *
  11. * Redistribution and use in source and binary forms, with or without
  12. * modification, are permitted provided that the following conditions
  13. * are met:
  14. * 1. Redistributions of source code must retain the above copyright
  15. * notice, this list of conditions and the following disclaimer.
  16. * 2. The name of the above contributors may not be
  17. * used to endorse or promote products derived from this software
  18. * without specific prior written permission.
  19. *
  20. * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
  21. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23. * ARE DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
  24. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30. * SUCH DAMAGE.
  31. */
  32. #include "ldso.h"
  33. #include "unsecvars.h"
  34. /* Pull in common debug code */
  35. #include "dl-debug.c"
  36. #define ALLOW_ZERO_PLTGOT
  37. /* Pull in the value of _dl_progname */
  38. #include LDSO_ELFINTERP
  39. /* Global variables used within the shared library loader */
  40. char *_dl_library_path = 0; /* Where we look for libraries */
  41. char *_dl_preload = 0; /* Things to be loaded before the libs */
  42. char *_dl_ldsopath = 0; /* Location of the shared lib loader */
  43. int _dl_secure = 1; /* Are we dealing with setuid stuff? */
  44. int _dl_errno = 0; /* We can't use the real errno in ldso */
  45. size_t _dl_pagesize = 0; /* Store the page size for use later */
  46. struct r_debug *_dl_debug_addr = NULL; /* Used to communicate with the gdb debugger */
  47. void *(*_dl_malloc_function) (size_t size) = NULL;
  48. #ifdef __SUPPORT_LD_DEBUG__
  49. char *_dl_debug = 0;
  50. char *_dl_debug_symbols = 0;
  51. char *_dl_debug_move = 0;
  52. char *_dl_debug_reloc = 0;
  53. char *_dl_debug_detail = 0;
  54. char *_dl_debug_nofixups = 0;
  55. char *_dl_debug_bindings = 0;
  56. int _dl_debug_file = 2;
  57. #endif
  58. /* Needed for standalone execution. */
  59. unsigned long attribute_hidden _dl_skip_args = 0;
  60. const char *_dl_progname = UCLIBC_LDSO; /* The name of the executable being run */
  61. #include "dl-startup.c"
  62. /* Forward function declarations */
  63. static int _dl_suid_ok(void);
  64. /*
  65. * This stub function is used by some debuggers. The idea is that they
  66. * can set an internal breakpoint on it, so that we are notified when the
  67. * address mapping is changed in some way.
  68. */
  69. void _dl_debug_state(void);
  70. void _dl_debug_state()
  71. {
  72. }
  73. static unsigned char *_dl_malloc_addr = 0; /* Lets _dl_malloc use the already allocated memory page */
  74. static unsigned char *_dl_mmap_zero = 0; /* Also used by _dl_malloc */
  75. static struct elf_resolve **init_fini_list;
  76. static unsigned int nlist; /* # items in init_fini_list */
  77. extern void _start(void);
  78. #ifdef __UCLIBC_HAS_SSP__
  79. #include <dl-osinfo.h>
  80. uintptr_t stack_chk_guard;
  81. #ifndef THREAD_SET_STACK_GUARD
  82. /* Only exported for architectures that don't store the stack guard canary
  83. * in local thread area. */
  84. uintptr_t __stack_chk_guard attribute_relro;
  85. strong_alias(__stack_chk_guard,__guard)
  86. #endif
  87. #endif
  88. static void _dl_run_array_forward(unsigned long array, unsigned long size,
  89. ElfW(Addr) loadaddr)
  90. {
  91. if (array != 0) {
  92. unsigned int j;
  93. unsigned int jm;
  94. ElfW(Addr) *addrs;
  95. jm = size / sizeof (ElfW(Addr));
  96. addrs = (ElfW(Addr) *) (array + loadaddr);
  97. for (j = 0; j < jm; ++j) {
  98. void (*dl_elf_func) (void);
  99. dl_elf_func = (void (*)(void)) (intptr_t) addrs[j];
  100. (*dl_elf_func) ();
  101. }
  102. }
  103. }
  104. void _dl_run_init_array(struct elf_resolve *tpnt);
  105. void _dl_run_init_array(struct elf_resolve *tpnt)
  106. {
  107. _dl_run_array_forward(tpnt->dynamic_info[DT_INIT_ARRAY],
  108. tpnt->dynamic_info[DT_INIT_ARRAYSZ],
  109. tpnt->loadaddr);
  110. }
  111. void _dl_app_init_array(void);
  112. void _dl_app_init_array(void)
  113. {
  114. _dl_run_init_array(_dl_loaded_modules);
  115. }
  116. void _dl_run_fini_array(struct elf_resolve *tpnt);
  117. void _dl_run_fini_array(struct elf_resolve *tpnt)
  118. {
  119. if (tpnt->dynamic_info[DT_FINI_ARRAY]) {
  120. ElfW(Addr) *array = (ElfW(Addr) *) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI_ARRAY]);
  121. unsigned int i = (tpnt->dynamic_info[DT_FINI_ARRAYSZ] / sizeof(ElfW(Addr)));
  122. while (i-- > 0) {
  123. void (*dl_elf_func) (void);
  124. dl_elf_func = (void (*)(void)) (intptr_t) array[i];
  125. (*dl_elf_func) ();
  126. }
  127. }
  128. }
  129. void _dl_app_fini_array(void);
  130. void _dl_app_fini_array(void)
  131. {
  132. _dl_run_fini_array(_dl_loaded_modules);
  133. }
  134. static void __attribute__ ((destructor)) __attribute_used__ _dl_fini(void)
  135. {
  136. int i;
  137. struct elf_resolve * tpnt;
  138. for (i = 0; i < nlist; ++i) {
  139. tpnt = init_fini_list[i];
  140. if (tpnt->init_flag & FINI_FUNCS_CALLED)
  141. continue;
  142. tpnt->init_flag |= FINI_FUNCS_CALLED;
  143. _dl_run_fini_array(tpnt);
  144. if (tpnt->dynamic_info[DT_FINI]) {
  145. void (*dl_elf_func) (void);
  146. dl_elf_func = (void (*)(void)) (intptr_t) (tpnt->loadaddr + tpnt->dynamic_info[DT_FINI]);
  147. _dl_if_debug_dprint("\ncalling FINI: %s\n\n", tpnt->libname);
  148. (*dl_elf_func) ();
  149. }
  150. }
  151. }
  152. void _dl_get_ready_to_run(struct elf_resolve *tpnt, unsigned long load_addr,
  153. ElfW(auxv_t) auxvt[AT_EGID + 1], char **envp,
  154. char **argv)
  155. {
  156. ElfW(Phdr) *ppnt;
  157. ElfW(Dyn) *dpnt;
  158. char *lpntstr;
  159. unsigned int i;
  160. int unlazy = 0, trace_loaded_objects = 0;
  161. struct dyn_elf *rpnt;
  162. struct elf_resolve *tcurr;
  163. struct elf_resolve *tpnt1;
  164. struct elf_resolve app_tpnt_tmp;
  165. struct elf_resolve *app_tpnt = &app_tpnt_tmp;
  166. struct r_debug *debug_addr;
  167. unsigned long *lpnt;
  168. unsigned long *_dl_envp; /* The environment address */
  169. ElfW(Addr) relro_addr = 0;
  170. size_t relro_size = 0;
  171. /* Wahoo!!! We managed to make a function call! Get malloc
  172. * setup so we can use _dl_dprintf() to print debug noise
  173. * instead of the SEND_STDERR macros used in dl-startup.c */
  174. _dl_memset(app_tpnt, 0x00, sizeof(*app_tpnt));
  175. /* Store the page size for later use */
  176. _dl_pagesize = (auxvt[AT_PAGESZ].a_un.a_val) ? (size_t) auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
  177. /* Make it so _dl_malloc can use the page of memory we have already
  178. * allocated. We shouldn't need to grab any more memory. This must
  179. * be first since things like _dl_dprintf() use _dl_malloc()...
  180. */
  181. _dl_malloc_addr = (unsigned char *)_dl_pagesize;
  182. _dl_mmap_zero = 0;
  183. /* Wahoo!!! */
  184. _dl_debug_early("Cool, ldso survived making function calls\n");
  185. /* Now we have done the mandatory linking of some things. We are now
  186. * free to start using global variables, since these things have all
  187. * been fixed up by now. Still no function calls outside of this
  188. * library, since the dynamic resolver is not yet ready.
  189. */
  190. if (argv[0]) {
  191. _dl_progname = argv[0];
  192. }
  193. if (_start == (void *) auxvt[AT_ENTRY].a_un.a_val) {
  194. _dl_dprintf(_dl_debug_file, "Standalone execution is not supported yet\n");
  195. _dl_exit(1);
  196. }
  197. /* Start to build the tables of the modules that are required for
  198. * this beast to run. We start with the basic executable, and then
  199. * go from there. Eventually we will run across ourself, and we
  200. * will need to properly deal with that as well.
  201. */
  202. rpnt = NULL;
  203. if (_dl_getenv("LD_BIND_NOW", envp))
  204. unlazy = RTLD_NOW;
  205. /* Now we need to figure out what kind of options are selected.
  206. * Note that for SUID programs we ignore the settings in
  207. * LD_LIBRARY_PATH.
  208. */
  209. if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && _dl_suid_ok()) ||
  210. (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
  211. auxvt[AT_UID].a_un.a_val == auxvt[AT_EUID].a_un.a_val &&
  212. auxvt[AT_GID].a_un.a_val == auxvt[AT_EGID].a_un.a_val)) {
  213. _dl_secure = 0;
  214. _dl_preload = _dl_getenv("LD_PRELOAD", envp);
  215. _dl_library_path = _dl_getenv("LD_LIBRARY_PATH", envp);
  216. } else {
  217. static const char unsecure_envvars[] =
  218. #ifdef EXTRA_UNSECURE_ENVVARS
  219. EXTRA_UNSECURE_ENVVARS
  220. #endif
  221. UNSECURE_ENVVARS;
  222. const char *nextp;
  223. _dl_secure = 1;
  224. nextp = unsecure_envvars;
  225. do {
  226. _dl_unsetenv (nextp, envp);
  227. /* We could use rawmemchr but this need not be fast. */
  228. nextp = (char *) _dl_strchr(nextp, '\0') + 1;
  229. } while (*nextp != '\0');
  230. _dl_preload = NULL;
  231. _dl_library_path = NULL;
  232. /* SUID binaries can be exploited if they do LAZY relocation. */
  233. unlazy = RTLD_NOW;
  234. }
  235. /* sjhill: your TLS init should go before this */
  236. #ifdef __UCLIBC_HAS_SSP__
  237. /* Set up the stack checker's canary. */
  238. stack_chk_guard = _dl_setup_stack_chk_guard ();
  239. # ifdef THREAD_SET_STACK_GUARD
  240. THREAD_SET_STACK_GUARD (stack_chk_guard);
  241. # else
  242. __stack_chk_guard = stack_chk_guard;
  243. # endif
  244. #endif
  245. /* At this point we are now free to examine the user application,
  246. * and figure out which libraries are supposed to be called. Until
  247. * we have this list, we will not be completely ready for dynamic
  248. * linking.
  249. */
  250. /* Find the runtime load address of the main executable. This may be
  251. * different from what the ELF header says for ET_DYN/PIE executables.
  252. */
  253. {
  254. unsigned int idx;
  255. ElfW(Phdr) *phdr = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
  256. for (idx = 0; idx < auxvt[AT_PHNUM].a_un.a_val; idx++, phdr++)
  257. if (phdr->p_type == PT_PHDR) {
  258. app_tpnt->loadaddr = (ElfW(Addr)) (auxvt[AT_PHDR].a_un.a_val - phdr->p_vaddr);
  259. break;
  260. }
  261. if (app_tpnt->loadaddr)
  262. _dl_debug_early("Position Independent Executable: "
  263. "app_tpnt->loadaddr=%x\n", app_tpnt->loadaddr);
  264. }
  265. /*
  266. * This is used by gdb to locate the chain of shared libraries that are
  267. * currently loaded.
  268. */
  269. debug_addr = _dl_malloc(sizeof(struct r_debug));
  270. _dl_memset(debug_addr, 0, sizeof(struct r_debug));
  271. ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
  272. for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
  273. if (ppnt->p_type == PT_GNU_RELRO) {
  274. relro_addr = ppnt->p_vaddr;
  275. relro_size = ppnt->p_memsz;
  276. }
  277. if (ppnt->p_type == PT_DYNAMIC) {
  278. dpnt = (ElfW(Dyn) *) (ppnt->p_vaddr + app_tpnt->loadaddr);
  279. _dl_parse_dynamic_info(dpnt, app_tpnt->dynamic_info, debug_addr, app_tpnt->loadaddr);
  280. #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
  281. /* Ugly, ugly. We need to call mprotect to change the
  282. * protection of the text pages so that we can do the
  283. * dynamic linking. We can set the protection back
  284. * again once we are done.
  285. */
  286. _dl_debug_early("calling mprotect on the application program\n");
  287. /* Now cover the application program. */
  288. if (app_tpnt->dynamic_info[DT_TEXTREL]) {
  289. ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
  290. for (i = 0; i < auxvt[AT_PHNUM].a_un.a_val; i++, ppnt++) {
  291. if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
  292. _dl_mprotect((void *) ((ppnt->p_vaddr + app_tpnt->loadaddr) & PAGE_ALIGN),
  293. ((ppnt->p_vaddr + app_tpnt->loadaddr) & ADDR_ALIGN) +
  294. (unsigned long) ppnt->p_filesz,
  295. PROT_READ | PROT_WRITE | PROT_EXEC);
  296. }
  297. }
  298. #endif
  299. #ifndef ALLOW_ZERO_PLTGOT
  300. /* make sure it's really there. */
  301. if (app_tpnt->dynamic_info[DT_PLTGOT] == 0)
  302. continue;
  303. #endif
  304. /* OK, we have what we need - slip this one into the list. */
  305. app_tpnt = _dl_add_elf_hash_table(_dl_progname, (char *)app_tpnt->loadaddr,
  306. app_tpnt->dynamic_info, ppnt->p_vaddr + app_tpnt->loadaddr, ppnt->p_filesz);
  307. _dl_loaded_modules->libtype = elf_executable;
  308. _dl_loaded_modules->ppnt = (ElfW(Phdr) *) auxvt[AT_PHDR].a_un.a_val;
  309. _dl_loaded_modules->n_phent = auxvt[AT_PHNUM].a_un.a_val;
  310. _dl_symbol_tables = rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
  311. _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
  312. rpnt->dyn = _dl_loaded_modules;
  313. app_tpnt->rtld_flags = unlazy | RTLD_GLOBAL;
  314. app_tpnt->usage_count++;
  315. app_tpnt->symbol_scope = _dl_symbol_tables;
  316. lpnt = (unsigned long *) (app_tpnt->dynamic_info[DT_PLTGOT]);
  317. #ifdef ALLOW_ZERO_PLTGOT
  318. if (lpnt)
  319. #endif
  320. INIT_GOT(lpnt, _dl_loaded_modules);
  321. }
  322. /* OK, fill this in - we did not have this before */
  323. if (ppnt->p_type == PT_INTERP) {
  324. char *ptmp;
  325. tpnt->libname = (char *) ppnt->p_vaddr + app_tpnt->loadaddr;
  326. /* Store the path where the shared lib loader was found
  327. * for later use
  328. */
  329. _dl_ldsopath = _dl_strdup(tpnt->libname);
  330. ptmp = _dl_strrchr(_dl_ldsopath, '/');
  331. if (ptmp != _dl_ldsopath)
  332. *ptmp = '\0';
  333. _dl_debug_early("Lib Loader: (%x) %s\n", tpnt->loadaddr, tpnt->libname);
  334. }
  335. }
  336. app_tpnt->relro_addr = relro_addr;
  337. app_tpnt->relro_size = relro_size;
  338. #ifdef __SUPPORT_LD_DEBUG__
  339. _dl_debug = _dl_getenv("LD_DEBUG", envp);
  340. if (_dl_debug) {
  341. if (_dl_strstr(_dl_debug, "all")) {
  342. _dl_debug_detail = _dl_debug_move = _dl_debug_symbols
  343. = _dl_debug_reloc = _dl_debug_bindings = _dl_debug_nofixups = (void*)1;
  344. } else {
  345. _dl_debug_detail = _dl_strstr(_dl_debug, "detail");
  346. _dl_debug_move = _dl_strstr(_dl_debug, "move");
  347. _dl_debug_symbols = _dl_strstr(_dl_debug, "sym");
  348. _dl_debug_reloc = _dl_strstr(_dl_debug, "reloc");
  349. _dl_debug_nofixups = _dl_strstr(_dl_debug, "nofix");
  350. _dl_debug_bindings = _dl_strstr(_dl_debug, "bind");
  351. }
  352. }
  353. {
  354. const char *dl_debug_output;
  355. dl_debug_output = _dl_getenv("LD_DEBUG_OUTPUT", envp);
  356. if (dl_debug_output) {
  357. char tmp[22], *tmp1, *filename;
  358. int len1, len2;
  359. _dl_memset(tmp, 0, sizeof(tmp));
  360. tmp1 = _dl_simple_ltoa( tmp, (unsigned long)_dl_getpid());
  361. len1 = _dl_strlen(dl_debug_output);
  362. len2 = _dl_strlen(tmp1);
  363. filename = _dl_malloc(len1+len2+2);
  364. if (filename) {
  365. _dl_strcpy (filename, dl_debug_output);
  366. filename[len1] = '.';
  367. _dl_strcpy (&filename[len1+1], tmp1);
  368. _dl_debug_file= _dl_open(filename, O_WRONLY|O_CREAT, 0644);
  369. if (_dl_debug_file < 0) {
  370. _dl_debug_file = 2;
  371. _dl_dprintf(_dl_debug_file, "can't open file: '%s'\n",filename);
  372. }
  373. }
  374. }
  375. }
  376. #endif
  377. if (_dl_getenv("LD_TRACE_LOADED_OBJECTS", envp) != NULL) {
  378. trace_loaded_objects++;
  379. }
  380. #ifndef __LDSO_LDD_SUPPORT__
  381. if (trace_loaded_objects) {
  382. _dl_dprintf(_dl_debug_file, "Use the ldd provided by uClibc\n");
  383. _dl_exit(1);
  384. }
  385. #endif
  386. /*
  387. * OK, fix one more thing - set up debug_addr so it will point
  388. * to our chain. Later we may need to fill in more fields, but this
  389. * should be enough for now.
  390. */
  391. debug_addr->r_map = (struct link_map *) _dl_loaded_modules;
  392. debug_addr->r_version = 1;
  393. debug_addr->r_ldbase = load_addr;
  394. debug_addr->r_brk = (unsigned long) &_dl_debug_state;
  395. _dl_debug_addr = debug_addr;
  396. /* Notify the debugger we are in a consistant state */
  397. _dl_debug_addr->r_state = RT_CONSISTENT;
  398. _dl_debug_state();
  399. /* OK, we now have the application in the list, and we have some
  400. * basic stuff in place. Now search through the list for other shared
  401. * libraries that should be loaded, and insert them on the list in the
  402. * correct order.
  403. */
  404. _dl_map_cache();
  405. if (_dl_preload) {
  406. char c, *str, *str2;
  407. str = _dl_preload;
  408. while (*str == ':' || *str == ' ' || *str == '\t')
  409. str++;
  410. while (*str) {
  411. str2 = str;
  412. while (*str2 && *str2 != ':' && *str2 != ' ' && *str2 != '\t')
  413. str2++;
  414. c = *str2;
  415. *str2 = '\0';
  416. if (!_dl_secure || _dl_strchr(str, '/') == NULL) {
  417. _dl_if_debug_dprint("\tfile='%s'; needed by '%s'\n", str, _dl_progname);
  418. tpnt1 = _dl_load_shared_library(_dl_secure, &rpnt, NULL, str, trace_loaded_objects);
  419. if (!tpnt1) {
  420. #ifdef __LDSO_LDD_SUPPORT__
  421. if (trace_loaded_objects)
  422. _dl_dprintf(1, "\t%s => not found\n", str);
  423. else
  424. #endif
  425. {
  426. _dl_dprintf(_dl_debug_file, "%s: can't load " "library '%s'\n", _dl_progname, str);
  427. _dl_exit(15);
  428. }
  429. } else {
  430. tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
  431. _dl_debug_early("Loading: (%x) %s\n", tpnt1->loadaddr, tpnt1->libname);
  432. #ifdef __LDSO_LDD_SUPPORT__
  433. if (trace_loaded_objects &&
  434. tpnt1->usage_count == 1) {
  435. /* This is a real hack to make
  436. * ldd not print the library
  437. * itself when run on a
  438. * library.
  439. */
  440. if (_dl_strcmp(_dl_progname, str) != 0)
  441. _dl_dprintf(1, "\t%s => %s (%x)\n", str, tpnt1->libname,
  442. tpnt1->loadaddr);
  443. }
  444. #endif
  445. }
  446. }
  447. *str2 = c;
  448. str = str2;
  449. while (*str == ':' || *str == ' ' || *str == '\t')
  450. str++;
  451. }
  452. }
  453. #ifdef __LDSO_PRELOAD_FILE_SUPPORT__
  454. do {
  455. struct stat st;
  456. char *preload;
  457. int fd;
  458. char c, *cp, *cp2;
  459. if (_dl_stat(LDSO_PRELOAD, &st) || st.st_size == 0) {
  460. break;
  461. }
  462. if ((fd = _dl_open(LDSO_PRELOAD, O_RDONLY, 0)) < 0) {
  463. _dl_dprintf(_dl_debug_file, "%s: can't open file '%s'\n",
  464. _dl_progname, LDSO_PRELOAD);
  465. break;
  466. }
  467. preload = (caddr_t) _dl_mmap(0, st.st_size + 1,
  468. PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
  469. _dl_close(fd);
  470. if (preload == (caddr_t) -1) {
  471. _dl_dprintf(_dl_debug_file, "%s: can't map file '%s'\n",
  472. _dl_progname, LDSO_PRELOAD);
  473. break;
  474. }
  475. /* convert all separators and comments to spaces */
  476. for (cp = preload; *cp; /*nada */ ) {
  477. if (*cp == ':' || *cp == '\t' || *cp == '\n') {
  478. *cp++ = ' ';
  479. } else if (*cp == '#') {
  480. do {
  481. *cp++ = ' ';
  482. } while (*cp != '\n' && *cp != '\0');
  483. } else {
  484. cp++;
  485. }
  486. }
  487. /* find start of first library */
  488. for (cp = preload; *cp && *cp == ' '; cp++)
  489. /*nada */ ;
  490. while (*cp) {
  491. /* find end of library */
  492. for (cp2 = cp; *cp && *cp != ' '; cp++)
  493. /*nada */ ;
  494. c = *cp;
  495. *cp = '\0';
  496. _dl_if_debug_dprint("\tfile='%s'; needed by '%s'\n", cp2, _dl_progname);
  497. tpnt1 = _dl_load_shared_library(0, &rpnt, NULL, cp2, trace_loaded_objects);
  498. if (!tpnt1) {
  499. #ifdef __LDSO_LDD_SUPPORT__
  500. if (trace_loaded_objects)
  501. _dl_dprintf(1, "\t%s => not found\n", cp2);
  502. else
  503. #endif
  504. {
  505. _dl_dprintf(_dl_debug_file, "%s: can't load library '%s'\n", _dl_progname, cp2);
  506. _dl_exit(15);
  507. }
  508. } else {
  509. tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
  510. _dl_debug_early("Loading: (%x) %s\n", tpnt1->loadaddr, tpnt1->libname);
  511. #ifdef __LDSO_LDD_SUPPORT__
  512. if (trace_loaded_objects &&
  513. tpnt1->usage_count == 1) {
  514. _dl_dprintf(1, "\t%s => %s (%x)\n",
  515. cp2, tpnt1->libname,
  516. (unsigned)tpnt1->loadaddr);
  517. }
  518. #endif
  519. }
  520. /* find start of next library */
  521. *cp = c;
  522. for ( /*nada */ ; *cp && *cp == ' '; cp++)
  523. /*nada */ ;
  524. }
  525. _dl_munmap(preload, st.st_size + 1);
  526. } while (0);
  527. #endif /* __LDSO_PRELOAD_FILE_SUPPORT__ */
  528. nlist = 0;
  529. for (tcurr = _dl_loaded_modules; tcurr; tcurr = tcurr->next) {
  530. ElfW(Dyn) *this_dpnt;
  531. nlist++;
  532. for (this_dpnt = (ElfW(Dyn) *) tcurr->dynamic_addr; this_dpnt->d_tag; this_dpnt++) {
  533. if (this_dpnt->d_tag == DT_NEEDED) {
  534. char *name;
  535. struct init_fini_list *tmp;
  536. lpntstr = (char*) (tcurr->dynamic_info[DT_STRTAB] + this_dpnt->d_un.d_val);
  537. name = _dl_get_last_path_component(lpntstr);
  538. if (_dl_strcmp(name, UCLIBC_LDSO) == 0)
  539. continue;
  540. _dl_if_debug_dprint("\tfile='%s'; needed by '%s'\n", lpntstr, _dl_progname);
  541. if (!(tpnt1 = _dl_load_shared_library(0, &rpnt, tcurr, lpntstr, trace_loaded_objects))) {
  542. #ifdef __LDSO_LDD_SUPPORT__
  543. if (trace_loaded_objects) {
  544. _dl_dprintf(1, "\t%s => not found\n", lpntstr);
  545. continue;
  546. } else
  547. #endif
  548. {
  549. _dl_dprintf(_dl_debug_file, "%s: can't load library '%s'\n", _dl_progname, lpntstr);
  550. _dl_exit(16);
  551. }
  552. }
  553. tmp = alloca(sizeof(struct init_fini_list)); /* Allocates on stack, no need to free this memory */
  554. tmp->tpnt = tpnt1;
  555. tmp->next = tcurr->init_fini;
  556. tcurr->init_fini = tmp;
  557. tpnt1->rtld_flags = unlazy | RTLD_GLOBAL;
  558. _dl_debug_early("Loading: (%x) %s\n", tpnt1->loadaddr, tpnt1->libname);
  559. #ifdef __LDSO_LDD_SUPPORT__
  560. if (trace_loaded_objects &&
  561. tpnt1->usage_count == 1) {
  562. _dl_dprintf(1, "\t%s => %s (%x)\n",
  563. lpntstr, tpnt1->libname,
  564. (unsigned)tpnt1->loadaddr);
  565. }
  566. #endif
  567. }
  568. }
  569. }
  570. _dl_unmap_cache();
  571. --nlist; /* Exclude the application. */
  572. init_fini_list = _dl_malloc(nlist * sizeof(struct elf_resolve *));
  573. i = 0;
  574. for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
  575. init_fini_list[i++] = tcurr;
  576. }
  577. /* Sort the INIT/FINI list in dependency order. */
  578. for (tcurr = _dl_loaded_modules->next; tcurr; tcurr = tcurr->next) {
  579. int j, k;
  580. for (j = 0; init_fini_list[j] != tcurr; ++j)
  581. /* Empty */;
  582. for (k = j + 1; k < nlist; ++k) {
  583. struct init_fini_list *runp = init_fini_list[k]->init_fini;
  584. for (; runp; runp = runp->next) {
  585. if (runp->tpnt == tcurr) {
  586. struct elf_resolve *here = init_fini_list[k];
  587. _dl_if_debug_dprint("Move %s from pos %d to %d in INIT/FINI list\n", here->libname, k, j);
  588. for (i = (k - j); i; --i)
  589. init_fini_list[i+j] = init_fini_list[i+j-1];
  590. init_fini_list[j] = here;
  591. ++j;
  592. break;
  593. }
  594. }
  595. }
  596. }
  597. #ifdef __SUPPORT_LD_DEBUG__
  598. if(_dl_debug) {
  599. _dl_dprintf(_dl_debug_file, "\nINIT/FINI order and dependencies:\n");
  600. for (i = 0; i < nlist; i++) {
  601. struct init_fini_list *tmp;
  602. _dl_dprintf(_dl_debug_file, "lib: %s has deps:\n",
  603. init_fini_list[i]->libname);
  604. tmp = init_fini_list[i]->init_fini;
  605. for (; tmp; tmp = tmp->next)
  606. _dl_dprintf(_dl_debug_file, " %s ", tmp->tpnt->libname);
  607. _dl_dprintf(_dl_debug_file, "\n");
  608. }
  609. }
  610. #endif
  611. /*
  612. * If the program interpreter is not in the module chain, add it.
  613. * This will be required for dlopen to be able to access the internal
  614. * functions in the dynamic linker and to relocate the interpreter
  615. * again once all libs are loaded.
  616. */
  617. if (tpnt) {
  618. ElfW(Ehdr) *epnt = (ElfW(Ehdr) *) auxvt[AT_BASE].a_un.a_val;
  619. ElfW(Phdr) *myppnt = (ElfW(Phdr) *) (load_addr + epnt->e_phoff);
  620. int j;
  621. tpnt = _dl_add_elf_hash_table(tpnt->libname, (char *)load_addr,
  622. tpnt->dynamic_info,
  623. (unsigned long)tpnt->dynamic_addr,
  624. 0);
  625. tpnt->n_phent = epnt->e_phnum;
  626. tpnt->ppnt = myppnt;
  627. for (j = 0; j < epnt->e_phnum; j++, myppnt++) {
  628. if (myppnt->p_type == PT_GNU_RELRO) {
  629. tpnt->relro_addr = myppnt->p_vaddr;
  630. tpnt->relro_size = myppnt->p_memsz;
  631. break;
  632. }
  633. }
  634. tpnt->libtype = program_interpreter;
  635. tpnt->usage_count++;
  636. tpnt->symbol_scope = _dl_symbol_tables;
  637. if (rpnt) {
  638. rpnt->next = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
  639. _dl_memset(rpnt->next, 0, sizeof(struct dyn_elf));
  640. rpnt->next->prev = rpnt;
  641. rpnt = rpnt->next;
  642. } else {
  643. rpnt = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
  644. _dl_memset(rpnt, 0, sizeof(struct dyn_elf));
  645. }
  646. rpnt->dyn = tpnt;
  647. tpnt->rtld_flags = RTLD_NOW | RTLD_GLOBAL; /* Must not be LAZY */
  648. #ifdef RERELOCATE_LDSO
  649. /* Only rerelocate functions for now. */
  650. tpnt->init_flag = RELOCS_DONE;
  651. lpnt = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT]);
  652. # ifdef ALLOW_ZERO_PLTGOT
  653. if (tpnt->dynamic_info[DT_PLTGOT])
  654. # endif
  655. INIT_GOT(lpnt, tpnt);
  656. #else
  657. tpnt->init_flag = RELOCS_DONE | JMP_RELOCS_DONE;
  658. #endif
  659. tpnt = NULL;
  660. }
  661. #ifdef __LDSO_LDD_SUPPORT__
  662. /* End of the line for ldd.... */
  663. if (trace_loaded_objects) {
  664. _dl_dprintf(1, "\t%s => %s (%x)\n",
  665. rpnt->dyn->libname + _dl_strlen(_dl_ldsopath) + 1,
  666. rpnt->dyn->libname, rpnt->dyn->loadaddr);
  667. _dl_exit(0);
  668. }
  669. #endif
  670. _dl_debug_early("Beginning relocation fixups\n");
  671. #ifdef __mips__
  672. /*
  673. * Relocation of the GOT entries for MIPS have to be done
  674. * after all the libraries have been loaded.
  675. */
  676. _dl_perform_mips_global_got_relocations(_dl_loaded_modules, !unlazy);
  677. #endif
  678. /*
  679. * OK, now all of the kids are tucked into bed in their proper
  680. * addresses. Now we go through and look for REL and RELA records that
  681. * indicate fixups to the GOT tables. We need to do this in reverse
  682. * order so that COPY directives work correctly.
  683. */
  684. if (_dl_symbol_tables)
  685. if (_dl_fixup(_dl_symbol_tables, unlazy))
  686. _dl_exit(-1);
  687. for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
  688. if (tpnt->relro_size)
  689. _dl_protect_relro (tpnt);
  690. }
  691. /* OK, at this point things are pretty much ready to run. Now we need
  692. * to touch up a few items that are required, and then we can let the
  693. * user application have at it. Note that the dynamic linker itself
  694. * is not guaranteed to be fully dynamicly linked if we are using
  695. * ld.so.1, so we have to look up each symbol individually.
  696. */
  697. _dl_envp = (unsigned long *) (intptr_t) _dl_find_hash("__environ", _dl_symbol_tables, NULL, 0);
  698. if (_dl_envp)
  699. *_dl_envp = (unsigned long) envp;
  700. #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
  701. {
  702. unsigned int j;
  703. ElfW(Phdr) *myppnt;
  704. /* We had to set the protections of all pages to R/W for
  705. * dynamic linking. Set text pages back to R/O.
  706. */
  707. for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
  708. for (myppnt = tpnt->ppnt, j = 0; j < tpnt->n_phent; j++, myppnt++) {
  709. if (myppnt->p_type == PT_LOAD && !(myppnt->p_flags & PF_W) && tpnt->dynamic_info[DT_TEXTREL]) {
  710. _dl_mprotect((void *) (tpnt->loadaddr + (myppnt->p_vaddr & PAGE_ALIGN)),
  711. (myppnt->p_vaddr & ADDR_ALIGN) + (unsigned long) myppnt->p_filesz, LXFLAGS(myppnt->p_flags));
  712. }
  713. }
  714. }
  715. }
  716. #endif
  717. /* Notify the debugger we have added some objects. */
  718. _dl_debug_addr->r_state = RT_ADD;
  719. _dl_debug_state();
  720. /* Run pre-initialization functions for the executable. */
  721. _dl_run_array_forward(_dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAY],
  722. _dl_loaded_modules->dynamic_info[DT_PREINIT_ARRAYSZ],
  723. _dl_loaded_modules->loadaddr);
  724. /* Run initialization functions for loaded objects. For the
  725. main executable, they will be run from __uClibc_main. */
  726. for (i = nlist; i; --i) {
  727. tpnt = init_fini_list[i-1];
  728. tpnt->init_fini = NULL; /* Clear, since alloca was used */
  729. if (tpnt->init_flag & INIT_FUNCS_CALLED)
  730. continue;
  731. tpnt->init_flag |= INIT_FUNCS_CALLED;
  732. if (tpnt->dynamic_info[DT_INIT]) {
  733. void (*dl_elf_func) (void);
  734. dl_elf_func = (void (*)(void)) (intptr_t) (tpnt->loadaddr + tpnt->dynamic_info[DT_INIT]);
  735. _dl_if_debug_dprint("calling INIT: %s\n\n", tpnt->libname);
  736. (*dl_elf_func) ();
  737. }
  738. _dl_run_init_array(tpnt);
  739. }
  740. /* Find the real malloc function and make ldso functions use that from now on */
  741. _dl_malloc_function = (void* (*)(size_t)) (intptr_t) _dl_find_hash("malloc",
  742. _dl_symbol_tables, NULL, ELF_RTYPE_CLASS_PLT);
  743. /* Notify the debugger that all objects are now mapped in. */
  744. _dl_debug_addr->r_state = RT_CONSISTENT;
  745. _dl_debug_state();
  746. }
  747. char *_dl_getenv(const char *symbol, char **envp)
  748. {
  749. char *pnt;
  750. const char *pnt1;
  751. while ((pnt = *envp++)) {
  752. pnt1 = symbol;
  753. while (*pnt && *pnt == *pnt1)
  754. pnt1++, pnt++;
  755. if (!*pnt || *pnt != '=' || *pnt1)
  756. continue;
  757. return pnt + 1;
  758. }
  759. return 0;
  760. }
  761. void _dl_unsetenv(const char *symbol, char **envp)
  762. {
  763. char *pnt;
  764. const char *pnt1;
  765. char **newenvp = envp;
  766. for (pnt = *envp; pnt; pnt = *++envp) {
  767. pnt1 = symbol;
  768. while (*pnt && *pnt == *pnt1)
  769. pnt1++, pnt++;
  770. if (!*pnt || *pnt != '=' || *pnt1)
  771. *newenvp++ = *envp;
  772. }
  773. *newenvp++ = *envp;
  774. return;
  775. }
  776. static int _dl_suid_ok(void)
  777. {
  778. __kernel_uid_t uid, euid;
  779. __kernel_gid_t gid, egid;
  780. uid = _dl_getuid();
  781. euid = _dl_geteuid();
  782. gid = _dl_getgid();
  783. egid = _dl_getegid();
  784. if(uid == euid && gid == egid) {
  785. return 1;
  786. }
  787. return 0;
  788. }
  789. void *_dl_malloc(int size)
  790. {
  791. void *retval;
  792. #if 0
  793. _dl_debug_early("request for %d bytes\n", size);
  794. #endif
  795. if (_dl_malloc_function)
  796. return (*_dl_malloc_function) (size);
  797. if (_dl_malloc_addr - _dl_mmap_zero + (unsigned)size > _dl_pagesize) {
  798. _dl_debug_early("mmapping more memory\n");
  799. _dl_mmap_zero = _dl_malloc_addr = _dl_mmap((void *) 0, size,
  800. PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  801. if (_dl_mmap_check_error(_dl_mmap_zero)) {
  802. _dl_dprintf(_dl_debug_file, "%s: mmap of a spare page failed!\n", _dl_progname);
  803. _dl_exit(20);
  804. }
  805. }
  806. retval = _dl_malloc_addr;
  807. _dl_malloc_addr += size;
  808. /*
  809. * Align memory to 4 byte boundary. Some platforms require this,
  810. * others simply get better performance.
  811. */
  812. _dl_malloc_addr = (unsigned char *) (((unsigned long) _dl_malloc_addr + 3) & ~(3));
  813. return retval;
  814. }
  815. #include "dl-hash.c"
  816. #include "dl-elf.c"