dl-elf.c 24 KB

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  1. /* vi: set sw=4 ts=4: */
  2. /*
  3. * This file contains the helper routines to load an ELF shared
  4. * library into memory and add the symbol table info to the chain.
  5. *
  6. * Copyright (C) 2000-2006 by Erik Andersen <andersen@codepoet.org>
  7. * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
  8. * David Engel, Hongjiu Lu and Mitch D'Souza
  9. *
  10. * Redistribution and use in source and binary forms, with or without
  11. * modification, are permitted provided that the following conditions
  12. * are met:
  13. * 1. Redistributions of source code must retain the above copyright
  14. * notice, this list of conditions and the following disclaimer.
  15. * 2. The name of the above contributors may not be
  16. * used to endorse or promote products derived from this software
  17. * without specific prior written permission.
  18. *
  19. * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
  20. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22. * ARE DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
  23. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29. * SUCH DAMAGE.
  30. */
  31. #include "ldso.h"
  32. #ifdef __LDSO_CACHE_SUPPORT__
  33. static caddr_t _dl_cache_addr = NULL;
  34. static size_t _dl_cache_size = 0;
  35. int _dl_map_cache(void)
  36. {
  37. int fd;
  38. struct stat st;
  39. header_t *header;
  40. libentry_t *libent;
  41. int i, strtabsize;
  42. if (_dl_cache_addr == (caddr_t) - 1)
  43. return -1;
  44. else if (_dl_cache_addr != NULL)
  45. return 0;
  46. if (_dl_stat(LDSO_CACHE, &st)
  47. || (fd = _dl_open(LDSO_CACHE, O_RDONLY, 0)) < 0) {
  48. _dl_cache_addr = (caddr_t) - 1; /* so we won't try again */
  49. return -1;
  50. }
  51. _dl_cache_size = st.st_size;
  52. _dl_cache_addr = _dl_mmap(0, _dl_cache_size, PROT_READ, LDSO_CACHE_MMAP_FLAGS, fd, 0);
  53. _dl_close(fd);
  54. if (_dl_mmap_check_error(_dl_cache_addr)) {
  55. _dl_dprintf(2, "%s:%i: can't map '%s'\n",
  56. _dl_progname, __LINE__, LDSO_CACHE);
  57. return -1;
  58. }
  59. header = (header_t *) _dl_cache_addr;
  60. if (_dl_cache_size < sizeof(header_t) ||
  61. _dl_memcmp(header->magic, LDSO_CACHE_MAGIC, LDSO_CACHE_MAGIC_LEN)
  62. || _dl_memcmp(header->version, LDSO_CACHE_VER, LDSO_CACHE_VER_LEN)
  63. || _dl_cache_size <
  64. (sizeof(header_t) + header->nlibs * sizeof(libentry_t))
  65. || _dl_cache_addr[_dl_cache_size - 1] != '\0')
  66. {
  67. _dl_dprintf(2, "%s: cache '%s' is corrupt\n", _dl_progname,
  68. LDSO_CACHE);
  69. goto fail;
  70. }
  71. strtabsize = _dl_cache_size - sizeof(header_t) -
  72. header->nlibs * sizeof(libentry_t);
  73. libent = (libentry_t *) & header[1];
  74. for (i = 0; i < header->nlibs; i++) {
  75. if (libent[i].sooffset >= strtabsize ||
  76. libent[i].liboffset >= strtabsize)
  77. {
  78. _dl_dprintf(2, "%s: cache '%s' is corrupt\n", _dl_progname, LDSO_CACHE);
  79. goto fail;
  80. }
  81. }
  82. return 0;
  83. fail:
  84. _dl_munmap(_dl_cache_addr, _dl_cache_size);
  85. _dl_cache_addr = (caddr_t) - 1;
  86. return -1;
  87. }
  88. int _dl_unmap_cache(void)
  89. {
  90. if (_dl_cache_addr == NULL || _dl_cache_addr == (caddr_t) - 1)
  91. return -1;
  92. #if 1
  93. _dl_munmap(_dl_cache_addr, _dl_cache_size);
  94. _dl_cache_addr = NULL;
  95. #endif
  96. return 0;
  97. }
  98. #endif
  99. void
  100. _dl_protect_relro (struct elf_resolve *l)
  101. {
  102. ElfW(Addr) base = (ElfW(Addr)) DL_RELOC_ADDR(l->loadaddr, l->relro_addr);
  103. ElfW(Addr) start = (base & ~(_dl_pagesize - 1));
  104. ElfW(Addr) end = ((base + l->relro_size) & ~(_dl_pagesize - 1));
  105. _dl_if_debug_dprint("RELRO protecting %s: start:%x, end:%x\n", l->libname, start, end);
  106. if (start != end &&
  107. _dl_mprotect ((void *) start, end - start, PROT_READ) < 0) {
  108. _dl_dprintf(2, "%s: cannot apply additional memory protection after relocation", l->libname);
  109. _dl_exit(0);
  110. }
  111. }
  112. /* This function's behavior must exactly match that
  113. * in uClibc/ldso/util/ldd.c */
  114. static struct elf_resolve *
  115. search_for_named_library(const char *name, int secure, const char *path_list,
  116. struct dyn_elf **rpnt)
  117. {
  118. char *path, *path_n, *mylibname;
  119. struct elf_resolve *tpnt;
  120. int done;
  121. if (path_list==NULL)
  122. return NULL;
  123. /* We need a writable copy of this string, but we don't
  124. * need this allocated permanently since we don't want
  125. * to leak memory, so use alloca to put path on the stack */
  126. done = _dl_strlen(path_list);
  127. path = alloca(done + 1);
  128. /* another bit of local storage */
  129. mylibname = alloca(2050);
  130. /* gcc inlines alloca using a single instruction adjusting
  131. * the stack pointer and no stack overflow check and thus
  132. * no NULL error return. No point leaving in dead code... */
  133. #if 0
  134. if (!path || !mylibname) {
  135. _dl_dprintf(2, "Out of memory!\n");
  136. _dl_exit(0);
  137. }
  138. #endif
  139. _dl_memcpy(path, path_list, done+1);
  140. /* Unlike ldd.c, don't bother to eliminate double //s */
  141. /* Replace colons with zeros in path_list */
  142. /* : at the beginning or end of path maps to CWD */
  143. /* :: anywhere maps CWD */
  144. /* "" maps to CWD */
  145. done = 0;
  146. path_n = path;
  147. do {
  148. if (*path == 0) {
  149. *path = ':';
  150. done = 1;
  151. }
  152. if (*path == ':') {
  153. *path = 0;
  154. if (*path_n)
  155. _dl_strcpy(mylibname, path_n);
  156. else
  157. _dl_strcpy(mylibname, "."); /* Assume current dir if empty path */
  158. _dl_strcat(mylibname, "/");
  159. _dl_strcat(mylibname, name);
  160. if ((tpnt = _dl_load_elf_shared_library(secure, rpnt, mylibname)) != NULL)
  161. return tpnt;
  162. path_n = path+1;
  163. }
  164. path++;
  165. } while (!done);
  166. return NULL;
  167. }
  168. /* Used to return error codes back to dlopen et. al. */
  169. unsigned long _dl_error_number;
  170. unsigned long _dl_internal_error_number;
  171. struct elf_resolve *_dl_load_shared_library(int secure, struct dyn_elf **rpnt,
  172. struct elf_resolve *tpnt, char *full_libname, int __attribute__((unused)) trace_loaded_objects)
  173. {
  174. char *pnt;
  175. struct elf_resolve *tpnt1;
  176. char *libname;
  177. _dl_internal_error_number = 0;
  178. libname = full_libname;
  179. /* quick hack to ensure mylibname buffer doesn't overflow. don't
  180. allow full_libname or any directory to be longer than 1024. */
  181. if (_dl_strlen(full_libname) > 1024)
  182. goto goof;
  183. /* Skip over any initial initial './' and '/' stuff to
  184. * get the short form libname with no path garbage */
  185. pnt = _dl_strrchr(libname, '/');
  186. if (pnt) {
  187. libname = pnt + 1;
  188. }
  189. _dl_if_debug_dprint("\tfind library='%s'; searching\n", libname);
  190. /* If the filename has any '/', try it straight and leave it at that.
  191. For IBCS2 compatibility under linux, we substitute the string
  192. /usr/i486-sysv4/lib for /usr/lib in library names. */
  193. if (libname != full_libname) {
  194. _dl_if_debug_dprint("\ttrying file='%s'\n", full_libname);
  195. tpnt1 = _dl_load_elf_shared_library(secure, rpnt, full_libname);
  196. if (tpnt1) {
  197. return tpnt1;
  198. }
  199. }
  200. /*
  201. * The ABI specifies that RPATH is searched before LD_LIBRARY_PATH or
  202. * the default path of /usr/lib. Check in rpath directories.
  203. */
  204. #ifdef __LDSO_RUNPATH__
  205. pnt = (tpnt ? (char *) tpnt->dynamic_info[DT_RPATH] : NULL);
  206. if (pnt) {
  207. pnt += (unsigned long) tpnt->dynamic_info[DT_STRTAB];
  208. _dl_if_debug_dprint("\tsearching RPATH='%s'\n", pnt);
  209. if ((tpnt1 = search_for_named_library(libname, secure, pnt, rpnt)) != NULL)
  210. return tpnt1;
  211. }
  212. #endif
  213. /* Check in LD_{ELF_}LIBRARY_PATH, if specified and allowed */
  214. if (_dl_library_path) {
  215. _dl_if_debug_dprint("\tsearching LD_LIBRARY_PATH='%s'\n", _dl_library_path);
  216. if ((tpnt1 = search_for_named_library(libname, secure, _dl_library_path, rpnt)) != NULL)
  217. {
  218. return tpnt1;
  219. }
  220. }
  221. /*
  222. * The ABI specifies that RUNPATH is searched after LD_LIBRARY_PATH.
  223. */
  224. #ifdef __LDSO_RUNPATH__
  225. pnt = (tpnt ? (char *)tpnt->dynamic_info[DT_RUNPATH] : NULL);
  226. if (pnt) {
  227. pnt += (unsigned long) tpnt->dynamic_info[DT_STRTAB];
  228. _dl_if_debug_dprint("\tsearching RUNPATH='%s'\n", pnt);
  229. if ((tpnt1 = search_for_named_library(libname, secure, pnt, rpnt)) != NULL)
  230. return tpnt1;
  231. }
  232. #endif
  233. /*
  234. * Where should the cache be searched? There is no such concept in the
  235. * ABI, so we have some flexibility here. For now, search it before
  236. * the hard coded paths that follow (i.e before /lib and /usr/lib).
  237. */
  238. #ifdef __LDSO_CACHE_SUPPORT__
  239. if (_dl_cache_addr != NULL && _dl_cache_addr != (caddr_t) - 1) {
  240. int i;
  241. header_t *header = (header_t *) _dl_cache_addr;
  242. libentry_t *libent = (libentry_t *) & header[1];
  243. char *strs = (char *) &libent[header->nlibs];
  244. _dl_if_debug_dprint("\tsearching cache='%s'\n", LDSO_CACHE);
  245. for (i = 0; i < header->nlibs; i++) {
  246. if ((libent[i].flags == LIB_ELF ||
  247. libent[i].flags == LIB_ELF_LIBC0 ||
  248. libent[i].flags == LIB_ELF_LIBC5) &&
  249. _dl_strcmp(libname, strs + libent[i].sooffset) == 0 &&
  250. (tpnt1 = _dl_load_elf_shared_library(secure,
  251. rpnt, strs + libent[i].liboffset)))
  252. return tpnt1;
  253. }
  254. }
  255. #endif
  256. /* Look for libraries wherever the shared library loader
  257. * was installed */
  258. _dl_if_debug_dprint("\tsearching ldso dir='%s'\n", _dl_ldsopath);
  259. if ((tpnt1 = search_for_named_library(libname, secure, _dl_ldsopath, rpnt)) != NULL)
  260. {
  261. return tpnt1;
  262. }
  263. /* Lastly, search the standard list of paths for the library.
  264. This list must exactly match the list in uClibc/ldso/util/ldd.c */
  265. _dl_if_debug_dprint("\tsearching full lib path list\n");
  266. if ((tpnt1 = search_for_named_library(libname, secure,
  267. UCLIBC_RUNTIME_PREFIX "lib:"
  268. UCLIBC_RUNTIME_PREFIX "usr/lib"
  269. #ifndef __LDSO_CACHE_SUPPORT__
  270. ":" UCLIBC_RUNTIME_PREFIX "usr/X11R6/lib"
  271. #endif
  272. , rpnt)
  273. ) != NULL)
  274. {
  275. return tpnt1;
  276. }
  277. goof:
  278. /* Well, we shot our wad on that one. All we can do now is punt */
  279. if (_dl_internal_error_number)
  280. _dl_error_number = _dl_internal_error_number;
  281. else
  282. _dl_error_number = LD_ERROR_NOFILE;
  283. _dl_if_debug_dprint("Bummer: could not find '%s'!\n", libname);
  284. return NULL;
  285. }
  286. /*
  287. * Read one ELF library into memory, mmap it into the correct locations and
  288. * add the symbol info to the symbol chain. Perform any relocations that
  289. * are required.
  290. */
  291. struct elf_resolve *_dl_load_elf_shared_library(int secure,
  292. struct dyn_elf **rpnt, char *libname)
  293. {
  294. ElfW(Ehdr) *epnt;
  295. unsigned long dynamic_addr = 0;
  296. ElfW(Dyn) *dpnt;
  297. struct elf_resolve *tpnt;
  298. ElfW(Phdr) *ppnt;
  299. char *status, *header;
  300. unsigned long dynamic_info[DYNAMIC_SIZE];
  301. unsigned long *lpnt;
  302. unsigned long libaddr;
  303. unsigned long minvma = 0xffffffff, maxvma = 0;
  304. int i, flags, piclib, infile;
  305. ElfW(Addr) relro_addr = 0;
  306. size_t relro_size = 0;
  307. struct stat st;
  308. DL_LOADADDR_TYPE lib_loadaddr;
  309. DL_INIT_LOADADDR_EXTRA_DECLS
  310. infile = _dl_open(libname, O_RDONLY, 0);
  311. if (infile < 0) {
  312. _dl_internal_error_number = LD_ERROR_NOFILE;
  313. return NULL;
  314. }
  315. if (_dl_fstat(infile, &st) < 0) {
  316. _dl_internal_error_number = LD_ERROR_NOFILE;
  317. _dl_close(infile);
  318. return NULL;
  319. }
  320. /* If we are in secure mode (i.e. a setu/gid binary using LD_PRELOAD),
  321. we don't load the library if it isn't setuid. */
  322. if (secure)
  323. if (!(st.st_mode & S_ISUID)) {
  324. _dl_close(infile);
  325. return NULL;
  326. }
  327. /* Check if file is already loaded */
  328. for (tpnt = _dl_loaded_modules; tpnt; tpnt = tpnt->next) {
  329. if (tpnt->st_dev == st.st_dev && tpnt->st_ino == st.st_ino) {
  330. /* Already loaded */
  331. tpnt->usage_count++;
  332. _dl_close(infile);
  333. return tpnt;
  334. }
  335. }
  336. header = _dl_mmap((void *) 0, _dl_pagesize, PROT_READ | PROT_WRITE,
  337. MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  338. if (_dl_mmap_check_error(header)) {
  339. _dl_dprintf(2, "%s:%i: can't map '%s'\n", _dl_progname, __LINE__, libname);
  340. _dl_internal_error_number = LD_ERROR_MMAP_FAILED;
  341. _dl_close(infile);
  342. return NULL;
  343. }
  344. _dl_read(infile, header, _dl_pagesize);
  345. epnt = (ElfW(Ehdr) *) (intptr_t) header;
  346. if (epnt->e_ident[0] != 0x7f ||
  347. epnt->e_ident[1] != 'E' ||
  348. epnt->e_ident[2] != 'L' ||
  349. epnt->e_ident[3] != 'F')
  350. {
  351. _dl_dprintf(2, "%s: '%s' is not an ELF file\n", _dl_progname,
  352. libname);
  353. _dl_internal_error_number = LD_ERROR_NOTELF;
  354. _dl_close(infile);
  355. _dl_munmap(header, _dl_pagesize);
  356. return NULL;
  357. }
  358. if ((epnt->e_type != ET_DYN) || (epnt->e_machine != MAGIC1
  359. #ifdef MAGIC2
  360. && epnt->e_machine != MAGIC2
  361. #endif
  362. ))
  363. {
  364. _dl_internal_error_number =
  365. (epnt->e_type != ET_DYN ? LD_ERROR_NOTDYN : LD_ERROR_NOTMAGIC);
  366. _dl_dprintf(2, "%s: '%s' is not an ELF executable for " ELF_TARGET
  367. "\n", _dl_progname, libname);
  368. _dl_close(infile);
  369. _dl_munmap(header, _dl_pagesize);
  370. return NULL;
  371. }
  372. ppnt = (ElfW(Phdr) *)(intptr_t) & header[epnt->e_phoff];
  373. piclib = 1;
  374. for (i = 0; i < epnt->e_phnum; i++) {
  375. if (ppnt->p_type == PT_DYNAMIC) {
  376. if (dynamic_addr)
  377. _dl_dprintf(2, "%s: '%s' has more than one dynamic section\n",
  378. _dl_progname, libname);
  379. dynamic_addr = ppnt->p_vaddr;
  380. }
  381. if (ppnt->p_type == PT_LOAD) {
  382. /* See if this is a PIC library. */
  383. if (i == 0 && ppnt->p_vaddr > 0x1000000) {
  384. piclib = 0;
  385. minvma = ppnt->p_vaddr;
  386. }
  387. if (piclib && ppnt->p_vaddr < minvma) {
  388. minvma = ppnt->p_vaddr;
  389. }
  390. if (((unsigned long) ppnt->p_vaddr + ppnt->p_memsz) > maxvma) {
  391. maxvma = ppnt->p_vaddr + ppnt->p_memsz;
  392. }
  393. }
  394. ppnt++;
  395. }
  396. maxvma = (maxvma + ADDR_ALIGN) & ~ADDR_ALIGN;
  397. minvma = minvma & ~0xffffU;
  398. flags = MAP_PRIVATE /*| MAP_DENYWRITE */ ;
  399. if (!piclib)
  400. flags |= MAP_FIXED;
  401. status = (char *) _dl_mmap((char *) (piclib ? 0 : minvma),
  402. maxvma - minvma, PROT_NONE, flags | MAP_ANONYMOUS, -1, 0);
  403. if (_dl_mmap_check_error(status)) {
  404. _dl_dprintf(2, "%s:%i: can't map '%s'\n", _dl_progname, __LINE__, libname);
  405. _dl_internal_error_number = LD_ERROR_MMAP_FAILED;
  406. _dl_close(infile);
  407. _dl_munmap(header, _dl_pagesize);
  408. return NULL;
  409. }
  410. libaddr = (unsigned long) status;
  411. flags |= MAP_FIXED;
  412. /* Get the memory to store the library */
  413. ppnt = (ElfW(Phdr) *)(intptr_t) & header[epnt->e_phoff];
  414. DL_INIT_LOADADDR(lib_loadaddr, libaddr, ppnt, epnt->e_phnum);
  415. for (i = 0; i < epnt->e_phnum; i++) {
  416. if (ppnt->p_type == PT_GNU_RELRO) {
  417. relro_addr = ppnt->p_vaddr;
  418. relro_size = ppnt->p_memsz;
  419. }
  420. if (ppnt->p_type == PT_LOAD) {
  421. /* See if this is a PIC library. */
  422. if (i == 0 && ppnt->p_vaddr > 0x1000000) {
  423. piclib = 0;
  424. /* flags |= MAP_FIXED; */
  425. }
  426. if (ppnt->p_flags & PF_W) {
  427. unsigned long map_size;
  428. char *cpnt;
  429. status = (char *) _dl_mmap((char *) ((piclib ? libaddr : 0) +
  430. (ppnt->p_vaddr & PAGE_ALIGN)), (ppnt->p_vaddr & ADDR_ALIGN)
  431. + ppnt->p_filesz, LXFLAGS(ppnt->p_flags), flags, infile,
  432. ppnt->p_offset & OFFS_ALIGN);
  433. if (_dl_mmap_check_error(status)) {
  434. _dl_dprintf(2, "%s:%i: can't map '%s'\n",
  435. _dl_progname, __LINE__, libname);
  436. _dl_internal_error_number = LD_ERROR_MMAP_FAILED;
  437. _dl_munmap((char *) libaddr, maxvma - minvma);
  438. _dl_close(infile);
  439. _dl_munmap(header, _dl_pagesize);
  440. return NULL;
  441. }
  442. /* Pad the last page with zeroes. */
  443. cpnt = (char *) (status + (ppnt->p_vaddr & ADDR_ALIGN) +
  444. ppnt->p_filesz);
  445. while (((unsigned long) cpnt) & ADDR_ALIGN)
  446. *cpnt++ = 0;
  447. /* I am not quite sure if this is completely
  448. * correct to do or not, but the basic way that
  449. * we handle bss segments is that we mmap
  450. * /dev/zero if there are any pages left over
  451. * that are not mapped as part of the file */
  452. map_size = (ppnt->p_vaddr + ppnt->p_filesz + ADDR_ALIGN) & PAGE_ALIGN;
  453. if (map_size < ppnt->p_vaddr + ppnt->p_memsz)
  454. status = (char *) _dl_mmap((char *) map_size +
  455. (piclib ? libaddr : 0),
  456. ppnt->p_vaddr + ppnt->p_memsz - map_size,
  457. LXFLAGS(ppnt->p_flags), flags | MAP_ANONYMOUS, -1, 0);
  458. } else
  459. status = (char *) _dl_mmap((char *) (ppnt->p_vaddr & PAGE_ALIGN)
  460. + (piclib ? libaddr : 0), (ppnt->p_vaddr & ADDR_ALIGN) +
  461. ppnt->p_filesz, LXFLAGS(ppnt->p_flags), flags,
  462. infile, ppnt->p_offset & OFFS_ALIGN);
  463. if (_dl_mmap_check_error(status)) {
  464. _dl_dprintf(2, "%s:%i: can't map '%s'\n", _dl_progname, __LINE__, libname);
  465. _dl_internal_error_number = LD_ERROR_MMAP_FAILED;
  466. _dl_munmap((char *) libaddr, maxvma - minvma);
  467. _dl_close(infile);
  468. _dl_munmap(header, _dl_pagesize);
  469. return NULL;
  470. }
  471. /* if (libaddr == 0 && piclib) {
  472. libaddr = (unsigned long) status;
  473. flags |= MAP_FIXED;
  474. } */
  475. }
  476. ppnt++;
  477. }
  478. _dl_close(infile);
  479. /* For a non-PIC library, the addresses are all absolute */
  480. if (piclib) {
  481. dynamic_addr = (unsigned long) DL_RELOC_ADDR(lib_loadaddr, dynamic_addr);
  482. }
  483. /*
  484. * OK, the ELF library is now loaded into VM in the correct locations
  485. * The next step is to go through and do the dynamic linking (if needed).
  486. */
  487. /* Start by scanning the dynamic section to get all of the pointers */
  488. if (!dynamic_addr) {
  489. _dl_internal_error_number = LD_ERROR_NODYNAMIC;
  490. _dl_dprintf(2, "%s: '%s' is missing a dynamic section\n",
  491. _dl_progname, libname);
  492. _dl_munmap(header, _dl_pagesize);
  493. return NULL;
  494. }
  495. dpnt = (ElfW(Dyn) *) dynamic_addr;
  496. _dl_memset(dynamic_info, 0, sizeof(dynamic_info));
  497. _dl_parse_dynamic_info(dpnt, dynamic_info, NULL, lib_loadaddr);
  498. /* If the TEXTREL is set, this means that we need to make the pages
  499. writable before we perform relocations. Do this now. They get set
  500. back again later. */
  501. if (dynamic_info[DT_TEXTREL]) {
  502. #ifndef __FORCE_SHAREABLE_TEXT_SEGMENTS__
  503. ppnt = (ElfW(Phdr) *)(intptr_t) & header[epnt->e_phoff];
  504. for (i = 0; i < epnt->e_phnum; i++, ppnt++) {
  505. if (ppnt->p_type == PT_LOAD && !(ppnt->p_flags & PF_W))
  506. _dl_mprotect((void *) ((piclib ? libaddr : 0) +
  507. (ppnt->p_vaddr & PAGE_ALIGN)),
  508. (ppnt->p_vaddr & ADDR_ALIGN) + (unsigned long) ppnt->p_filesz,
  509. PROT_READ | PROT_WRITE | PROT_EXEC);
  510. }
  511. #else
  512. _dl_dprintf(_dl_debug_file, "Can't modify %s's text section. Use GCC option -fPIC for shared objects, please.\n",libname);
  513. _dl_exit(1);
  514. #endif
  515. }
  516. tpnt = _dl_add_elf_hash_table(libname, lib_loadaddr, dynamic_info,
  517. dynamic_addr, 0);
  518. tpnt->relro_addr = relro_addr;
  519. tpnt->relro_size = relro_size;
  520. tpnt->st_dev = st.st_dev;
  521. tpnt->st_ino = st.st_ino;
  522. tpnt->ppnt = (ElfW(Phdr) *) DL_RELOC_ADDR(tpnt->loadaddr, epnt->e_phoff);
  523. tpnt->n_phent = epnt->e_phnum;
  524. /*
  525. * Add this object into the symbol chain
  526. */
  527. if (*rpnt) {
  528. (*rpnt)->next = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
  529. _dl_memset((*rpnt)->next, 0, sizeof(struct dyn_elf));
  530. (*rpnt)->next->prev = (*rpnt);
  531. *rpnt = (*rpnt)->next;
  532. }
  533. #ifndef SHARED
  534. /* When statically linked, the first time we dlopen a DSO
  535. * the *rpnt is NULL, so we need to allocate memory for it,
  536. * and initialize the _dl_symbol_table.
  537. */
  538. else {
  539. *rpnt = _dl_symbol_tables = (struct dyn_elf *) _dl_malloc(sizeof(struct dyn_elf));
  540. _dl_memset(*rpnt, 0, sizeof(struct dyn_elf));
  541. }
  542. #endif
  543. (*rpnt)->dyn = tpnt;
  544. tpnt->symbol_scope = _dl_symbol_tables;
  545. tpnt->usage_count++;
  546. tpnt->libtype = elf_lib;
  547. /*
  548. * OK, the next thing we need to do is to insert the dynamic linker into
  549. * the proper entry in the GOT so that the PLT symbols can be properly
  550. * resolved.
  551. */
  552. lpnt = (unsigned long *) dynamic_info[DT_PLTGOT];
  553. if (lpnt) {
  554. lpnt = (unsigned long *) (dynamic_info[DT_PLTGOT]);
  555. INIT_GOT(lpnt, tpnt);
  556. }
  557. _dl_if_debug_dprint("\n\tfile='%s'; generating link map\n", libname);
  558. _dl_if_debug_dprint("\t\tdynamic: %x base: %x\n", dynamic_addr, DL_LOADADDR_BASE(lib_loadaddr));
  559. _dl_if_debug_dprint("\t\t entry: %x phdr: %x phnum: %x\n\n",
  560. DL_RELOC_ADDR(lib_loadaddr, epnt->e_entry), tpnt->ppnt, tpnt->n_phent);
  561. _dl_munmap(header, _dl_pagesize);
  562. return tpnt;
  563. }
  564. /* now_flag must be RTLD_NOW or zero */
  565. int _dl_fixup(struct dyn_elf *rpnt, int now_flag)
  566. {
  567. int goof = 0;
  568. struct elf_resolve *tpnt;
  569. ElfW(Word) reloc_size, relative_count;
  570. ElfW(Addr) reloc_addr;
  571. if (rpnt->next)
  572. goof = _dl_fixup(rpnt->next, now_flag);
  573. if (goof)
  574. return goof;
  575. tpnt = rpnt->dyn;
  576. if (!(tpnt->init_flag & RELOCS_DONE))
  577. _dl_if_debug_dprint("relocation processing: %s\n", tpnt->libname);
  578. if (unlikely(tpnt->dynamic_info[UNSUPPORTED_RELOC_TYPE])) {
  579. _dl_if_debug_dprint("%s: can't handle %s relocation records\n",
  580. _dl_progname, UNSUPPORTED_RELOC_STR);
  581. goof++;
  582. return goof;
  583. }
  584. reloc_size = tpnt->dynamic_info[DT_RELOC_TABLE_SIZE];
  585. /* On some machines, notably SPARC & PPC, DT_REL* includes DT_JMPREL in its
  586. range. Note that according to the ELF spec, this is completely legal! */
  587. #ifdef ELF_MACHINE_PLTREL_OVERLAP
  588. reloc_size -= tpnt->dynamic_info [DT_PLTRELSZ];
  589. #endif
  590. if (tpnt->dynamic_info[DT_RELOC_TABLE_ADDR] &&
  591. !(tpnt->init_flag & RELOCS_DONE)) {
  592. reloc_addr = tpnt->dynamic_info[DT_RELOC_TABLE_ADDR];
  593. relative_count = tpnt->dynamic_info[DT_RELCONT_IDX];
  594. if (relative_count) { /* Optimize the XX_RELATIVE relocations if possible */
  595. reloc_size -= relative_count * sizeof(ELF_RELOC);
  596. elf_machine_relative(tpnt->loadaddr, reloc_addr, relative_count);
  597. reloc_addr += relative_count * sizeof(ELF_RELOC);
  598. }
  599. goof += _dl_parse_relocation_information(rpnt,
  600. reloc_addr,
  601. reloc_size);
  602. tpnt->init_flag |= RELOCS_DONE;
  603. }
  604. if (tpnt->dynamic_info[DT_BIND_NOW])
  605. now_flag = RTLD_NOW;
  606. if (tpnt->dynamic_info[DT_JMPREL] &&
  607. (!(tpnt->init_flag & JMP_RELOCS_DONE) ||
  608. (now_flag && !(tpnt->rtld_flags & now_flag)))) {
  609. tpnt->rtld_flags |= now_flag;
  610. if (!(tpnt->rtld_flags & RTLD_NOW)) {
  611. _dl_parse_lazy_relocation_information(rpnt,
  612. tpnt->dynamic_info[DT_JMPREL],
  613. tpnt->dynamic_info [DT_PLTRELSZ]);
  614. } else {
  615. goof += _dl_parse_relocation_information(rpnt,
  616. tpnt->dynamic_info[DT_JMPREL],
  617. tpnt->dynamic_info[DT_PLTRELSZ]);
  618. }
  619. tpnt->init_flag |= JMP_RELOCS_DONE;
  620. }
  621. return goof;
  622. }
  623. /* Minimal printf which handles only %s, %d, and %x */
  624. void _dl_dprintf(int fd, const char *fmt, ...)
  625. {
  626. #if __WORDSIZE > 32
  627. long int num;
  628. #else
  629. int num;
  630. #endif
  631. va_list args;
  632. char *start, *ptr, *string;
  633. static char *buf;
  634. if (!fmt)
  635. return;
  636. buf = _dl_mmap((void *) 0, _dl_pagesize, PROT_READ | PROT_WRITE,
  637. MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  638. if (_dl_mmap_check_error(buf)) {
  639. _dl_write(fd, "mmap of a spare page failed!\n", 29);
  640. _dl_exit(20);
  641. }
  642. start = ptr = buf;
  643. if (_dl_strlen(fmt) >= (_dl_pagesize - 1)) {
  644. _dl_write(fd, "overflow\n", 11);
  645. _dl_exit(20);
  646. }
  647. _dl_strcpy(buf, fmt);
  648. va_start(args, fmt);
  649. while (start) {
  650. while (*ptr != '%' && *ptr) {
  651. ptr++;
  652. }
  653. if (*ptr == '%') {
  654. *ptr++ = '\0';
  655. _dl_write(fd, start, _dl_strlen(start));
  656. switch (*ptr++) {
  657. case 's':
  658. string = va_arg(args, char *);
  659. if (!string)
  660. _dl_write(fd, "(null)", 6);
  661. else
  662. _dl_write(fd, string, _dl_strlen(string));
  663. break;
  664. case 'i':
  665. case 'd':
  666. {
  667. char tmp[22];
  668. #if __WORDSIZE > 32
  669. num = va_arg(args, long int);
  670. #else
  671. num = va_arg(args, int);
  672. #endif
  673. string = _dl_simple_ltoa(tmp, num);
  674. _dl_write(fd, string, _dl_strlen(string));
  675. break;
  676. }
  677. case 'x':
  678. case 'X':
  679. {
  680. char tmp[22];
  681. #if __WORDSIZE > 32
  682. num = va_arg(args, long int);
  683. #else
  684. num = va_arg(args, int);
  685. #endif
  686. string = _dl_simple_ltoahex(tmp, num);
  687. _dl_write(fd, string, _dl_strlen(string));
  688. break;
  689. }
  690. default:
  691. _dl_write(fd, "(null)", 6);
  692. break;
  693. }
  694. start = ptr;
  695. } else {
  696. _dl_write(fd, start, _dl_strlen(start));
  697. start = NULL;
  698. }
  699. }
  700. _dl_munmap(buf, _dl_pagesize);
  701. return;
  702. }
  703. char *_dl_strdup(const char *string)
  704. {
  705. char *retval;
  706. int len;
  707. len = _dl_strlen(string);
  708. retval = _dl_malloc(len + 1);
  709. _dl_strcpy(retval, string);
  710. return retval;
  711. }
  712. void _dl_parse_dynamic_info(ElfW(Dyn) *dpnt, unsigned long dynamic_info[],
  713. void *debug_addr, DL_LOADADDR_TYPE load_off)
  714. {
  715. __dl_parse_dynamic_info(dpnt, dynamic_info, debug_addr, load_off);
  716. }
  717. /* we want this in ldso.so and libdl.a but nowhere else */
  718. #ifdef __USE_GNU
  719. #if defined IS_IN_rtld || (defined IS_IN_libdl && ! defined SHARED)
  720. extern __typeof(dl_iterate_phdr) __dl_iterate_phdr;
  721. int
  722. __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info, size_t size, void *data), void *data)
  723. {
  724. struct elf_resolve *l;
  725. struct dl_phdr_info info;
  726. int ret = 0;
  727. for (l = _dl_loaded_modules; l != NULL; l = l->next) {
  728. info.dlpi_addr = l->loadaddr;
  729. info.dlpi_name = l->libname;
  730. info.dlpi_phdr = l->ppnt;
  731. info.dlpi_phnum = l->n_phent;
  732. ret = callback (&info, sizeof (struct dl_phdr_info), data);
  733. if (ret)
  734. break;
  735. }
  736. return ret;
  737. }
  738. strong_alias(__dl_iterate_phdr, dl_iterate_phdr)
  739. #endif
  740. #endif