1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/uio.h> 44 #include <sys/utsname.h> 45 #include <sys/ktrace.h> 46 47 #include <dlfcn.h> 48 #include <err.h> 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <stdarg.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #include "debug.h" 58 #include "rtld.h" 59 #include "libmap.h" 60 #include "rtld_tls.h" 61 62 #ifndef COMPAT_32BIT 63 #define PATH_RTLD "/libexec/ld-elf.so.1" 64 #else 65 #define PATH_RTLD "/libexec/ld-elf32.so.1" 66 #endif 67 68 /* Types. */ 69 typedef void (*func_ptr_type)(); 70 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 71 72 /* 73 * This structure provides a reentrant way to keep a list of objects and 74 * check which ones have already been processed in some way. 75 */ 76 typedef struct Struct_DoneList { 77 const Obj_Entry **objs; /* Array of object pointers */ 78 unsigned int num_alloc; /* Allocated size of the array */ 79 unsigned int num_used; /* Number of array slots used */ 80 } DoneList; 81 82 /* 83 * Function declarations. 84 */ 85 static const char *basename(const char *); 86 static void die(void) __dead2; 87 static void digest_dynamic(Obj_Entry *, int); 88 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 89 static Obj_Entry *dlcheck(void *); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *); 97 static const char *gethints(void); 98 static void init_dag(Obj_Entry *); 99 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 100 static void init_rtld(caddr_t); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static bool is_exported(const Elf_Sym *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static int load_needed_objects(Obj_Entry *); 107 static int load_preload_objects(void); 108 static Obj_Entry *load_object(const char *, const Obj_Entry *); 109 static Obj_Entry *obj_from_addr(const void *); 110 static void objlist_call_fini(Objlist *, int *lockstate); 111 static void objlist_call_init(Objlist *, int *lockstate); 112 static void objlist_clear(Objlist *); 113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114 static void objlist_init(Objlist *); 115 static void objlist_push_head(Objlist *, Obj_Entry *); 116 static void objlist_push_tail(Objlist *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static void objlist_remove_unref(Objlist *); 119 static void *path_enumerate(const char *, path_enum_proc, void *); 120 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 121 static int rtld_dirname(const char *, char *); 122 static int rtld_dirname_abs(const char *, char *); 123 static void rtld_exit(void); 124 static char *search_library_path(const char *, const char *); 125 static const void **get_program_var_addr(const char *); 126 static void set_program_var(const char *, const void *); 127 static const Elf_Sym *symlook_default(const char *, unsigned long, 128 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 129 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 130 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 131 static const Elf_Sym *symlook_needed(const char *, unsigned long, 132 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 133 int, DoneList *); 134 static void trace_loaded_objects(Obj_Entry *); 135 static void unlink_object(Obj_Entry *); 136 static void unload_object(Obj_Entry *); 137 static void unref_dag(Obj_Entry *); 138 static void ref_dag(Obj_Entry *); 139 static int origin_subst_one(char **res, const char *real, const char *kw, 140 const char *subst, char *may_free); 141 static char *origin_subst(const char *real, const char *origin_path); 142 static int rtld_verify_versions(const Objlist *); 143 static int rtld_verify_object_versions(Obj_Entry *); 144 static void object_add_name(Obj_Entry *, const char *); 145 static int object_match_name(const Obj_Entry *, const char *); 146 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 147 148 void r_debug_state(struct r_debug *, struct link_map *); 149 150 /* 151 * Data declarations. 152 */ 153 static char *error_message; /* Message for dlerror(), or NULL */ 154 struct r_debug r_debug; /* for GDB; */ 155 static bool libmap_disable; /* Disable libmap */ 156 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 157 static bool trust; /* False for setuid and setgid programs */ 158 static bool dangerous_ld_env; /* True if environment variables have been 159 used to affect the libraries loaded */ 160 static char *ld_bind_now; /* Environment variable for immediate binding */ 161 static char *ld_debug; /* Environment variable for debugging */ 162 static char *ld_library_path; /* Environment variable for search path */ 163 static char *ld_preload; /* Environment variable for libraries to 164 load first */ 165 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 166 static char *ld_tracing; /* Called from ldd to print libs */ 167 static char *ld_utrace; /* Use utrace() to log events. */ 168 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 169 static Obj_Entry **obj_tail; /* Link field of last object in list */ 170 static Obj_Entry *obj_main; /* The main program shared object */ 171 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 172 static unsigned int obj_count; /* Number of objects in obj_list */ 173 static unsigned int obj_loads; /* Number of objects in obj_list */ 174 175 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 176 STAILQ_HEAD_INITIALIZER(list_global); 177 static Objlist list_main = /* Objects loaded at program startup */ 178 STAILQ_HEAD_INITIALIZER(list_main); 179 static Objlist list_fini = /* Objects needing fini() calls */ 180 STAILQ_HEAD_INITIALIZER(list_fini); 181 182 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 183 184 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 185 186 extern Elf_Dyn _DYNAMIC; 187 #pragma weak _DYNAMIC 188 #ifndef RTLD_IS_DYNAMIC 189 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 190 #endif 191 192 /* 193 * These are the functions the dynamic linker exports to application 194 * programs. They are the only symbols the dynamic linker is willing 195 * to export from itself. 196 */ 197 static func_ptr_type exports[] = { 198 (func_ptr_type) &_rtld_error, 199 (func_ptr_type) &dlclose, 200 (func_ptr_type) &dlerror, 201 (func_ptr_type) &dlopen, 202 (func_ptr_type) &dlsym, 203 (func_ptr_type) &dlvsym, 204 (func_ptr_type) &dladdr, 205 (func_ptr_type) &dllockinit, 206 (func_ptr_type) &dlinfo, 207 (func_ptr_type) &_rtld_thread_init, 208 #ifdef __i386__ 209 (func_ptr_type) &___tls_get_addr, 210 #endif 211 (func_ptr_type) &__tls_get_addr, 212 (func_ptr_type) &_rtld_allocate_tls, 213 (func_ptr_type) &_rtld_free_tls, 214 (func_ptr_type) &dl_iterate_phdr, 215 (func_ptr_type) &_rtld_atfork_pre, 216 (func_ptr_type) &_rtld_atfork_post, 217 NULL 218 }; 219 220 /* 221 * Global declarations normally provided by crt1. The dynamic linker is 222 * not built with crt1, so we have to provide them ourselves. 223 */ 224 char *__progname; 225 char **environ; 226 227 /* 228 * Globals to control TLS allocation. 229 */ 230 size_t tls_last_offset; /* Static TLS offset of last module */ 231 size_t tls_last_size; /* Static TLS size of last module */ 232 size_t tls_static_space; /* Static TLS space allocated */ 233 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 234 int tls_max_index = 1; /* Largest module index allocated */ 235 236 /* 237 * Fill in a DoneList with an allocation large enough to hold all of 238 * the currently-loaded objects. Keep this as a macro since it calls 239 * alloca and we want that to occur within the scope of the caller. 240 */ 241 #define donelist_init(dlp) \ 242 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 243 assert((dlp)->objs != NULL), \ 244 (dlp)->num_alloc = obj_count, \ 245 (dlp)->num_used = 0) 246 247 #define UTRACE_DLOPEN_START 1 248 #define UTRACE_DLOPEN_STOP 2 249 #define UTRACE_DLCLOSE_START 3 250 #define UTRACE_DLCLOSE_STOP 4 251 #define UTRACE_LOAD_OBJECT 5 252 #define UTRACE_UNLOAD_OBJECT 6 253 #define UTRACE_ADD_RUNDEP 7 254 #define UTRACE_PRELOAD_FINISHED 8 255 #define UTRACE_INIT_CALL 9 256 #define UTRACE_FINI_CALL 10 257 258 struct utrace_rtld { 259 char sig[4]; /* 'RTLD' */ 260 int event; 261 void *handle; 262 void *mapbase; /* Used for 'parent' and 'init/fini' */ 263 size_t mapsize; 264 int refcnt; /* Used for 'mode' */ 265 char name[MAXPATHLEN]; 266 }; 267 268 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 269 if (ld_utrace != NULL) \ 270 ld_utrace_log(e, h, mb, ms, r, n); \ 271 } while (0) 272 273 static void 274 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 275 int refcnt, const char *name) 276 { 277 struct utrace_rtld ut; 278 279 ut.sig[0] = 'R'; 280 ut.sig[1] = 'T'; 281 ut.sig[2] = 'L'; 282 ut.sig[3] = 'D'; 283 ut.event = event; 284 ut.handle = handle; 285 ut.mapbase = mapbase; 286 ut.mapsize = mapsize; 287 ut.refcnt = refcnt; 288 bzero(ut.name, sizeof(ut.name)); 289 if (name) 290 strlcpy(ut.name, name, sizeof(ut.name)); 291 utrace(&ut, sizeof(ut)); 292 } 293 294 /* 295 * Main entry point for dynamic linking. The first argument is the 296 * stack pointer. The stack is expected to be laid out as described 297 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 298 * Specifically, the stack pointer points to a word containing 299 * ARGC. Following that in the stack is a null-terminated sequence 300 * of pointers to argument strings. Then comes a null-terminated 301 * sequence of pointers to environment strings. Finally, there is a 302 * sequence of "auxiliary vector" entries. 303 * 304 * The second argument points to a place to store the dynamic linker's 305 * exit procedure pointer and the third to a place to store the main 306 * program's object. 307 * 308 * The return value is the main program's entry point. 309 */ 310 func_ptr_type 311 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 312 { 313 Elf_Auxinfo *aux_info[AT_COUNT]; 314 int i; 315 int argc; 316 char **argv; 317 char **env; 318 Elf_Auxinfo *aux; 319 Elf_Auxinfo *auxp; 320 const char *argv0; 321 Objlist_Entry *entry; 322 Obj_Entry *obj; 323 Obj_Entry **preload_tail; 324 Objlist initlist; 325 int lockstate; 326 327 /* 328 * On entry, the dynamic linker itself has not been relocated yet. 329 * Be very careful not to reference any global data until after 330 * init_rtld has returned. It is OK to reference file-scope statics 331 * and string constants, and to call static and global functions. 332 */ 333 334 /* Find the auxiliary vector on the stack. */ 335 argc = *sp++; 336 argv = (char **) sp; 337 sp += argc + 1; /* Skip over arguments and NULL terminator */ 338 env = (char **) sp; 339 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 340 ; 341 aux = (Elf_Auxinfo *) sp; 342 343 /* Digest the auxiliary vector. */ 344 for (i = 0; i < AT_COUNT; i++) 345 aux_info[i] = NULL; 346 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 347 if (auxp->a_type < AT_COUNT) 348 aux_info[auxp->a_type] = auxp; 349 } 350 351 /* Initialize and relocate ourselves. */ 352 assert(aux_info[AT_BASE] != NULL); 353 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 354 355 __progname = obj_rtld.path; 356 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 357 environ = env; 358 359 trust = !issetugid(); 360 361 ld_bind_now = getenv(LD_ "BIND_NOW"); 362 /* 363 * If the process is tainted, then we un-set the dangerous environment 364 * variables. The process will be marked as tainted until setuid(2) 365 * is called. If any child process calls setuid(2) we do not want any 366 * future processes to honor the potentially un-safe variables. 367 */ 368 if (!trust) { 369 unsetenv(LD_ "PRELOAD"); 370 unsetenv(LD_ "LIBMAP"); 371 unsetenv(LD_ "LIBRARY_PATH"); 372 unsetenv(LD_ "LIBMAP_DISABLE"); 373 unsetenv(LD_ "DEBUG"); 374 unsetenv(LD_ "ELF_HINTS_PATH"); 375 } 376 ld_debug = getenv(LD_ "DEBUG"); 377 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 378 libmap_override = getenv(LD_ "LIBMAP"); 379 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 380 ld_preload = getenv(LD_ "PRELOAD"); 381 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 382 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 383 (ld_library_path != NULL) || (ld_preload != NULL) || 384 (ld_elf_hints_path != NULL); 385 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 386 ld_utrace = getenv(LD_ "UTRACE"); 387 388 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 389 ld_elf_hints_path = _PATH_ELF_HINTS; 390 391 if (ld_debug != NULL && *ld_debug != '\0') 392 debug = 1; 393 dbg("%s is initialized, base address = %p", __progname, 394 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 395 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 396 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 397 398 /* 399 * Load the main program, or process its program header if it is 400 * already loaded. 401 */ 402 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 403 int fd = aux_info[AT_EXECFD]->a_un.a_val; 404 dbg("loading main program"); 405 obj_main = map_object(fd, argv0, NULL); 406 close(fd); 407 if (obj_main == NULL) 408 die(); 409 } else { /* Main program already loaded. */ 410 const Elf_Phdr *phdr; 411 int phnum; 412 caddr_t entry; 413 414 dbg("processing main program's program header"); 415 assert(aux_info[AT_PHDR] != NULL); 416 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 417 assert(aux_info[AT_PHNUM] != NULL); 418 phnum = aux_info[AT_PHNUM]->a_un.a_val; 419 assert(aux_info[AT_PHENT] != NULL); 420 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 421 assert(aux_info[AT_ENTRY] != NULL); 422 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 423 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 424 die(); 425 } 426 427 if (aux_info[AT_EXECPATH] != 0) { 428 char *kexecpath; 429 char buf[MAXPATHLEN]; 430 431 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 432 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 433 if (kexecpath[0] == '/') 434 obj_main->path = kexecpath; 435 else if (getcwd(buf, sizeof(buf)) == NULL || 436 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 437 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 438 obj_main->path = xstrdup(argv0); 439 else 440 obj_main->path = xstrdup(buf); 441 } else { 442 dbg("No AT_EXECPATH"); 443 obj_main->path = xstrdup(argv0); 444 } 445 dbg("obj_main path %s", obj_main->path); 446 obj_main->mainprog = true; 447 448 /* 449 * Get the actual dynamic linker pathname from the executable if 450 * possible. (It should always be possible.) That ensures that 451 * gdb will find the right dynamic linker even if a non-standard 452 * one is being used. 453 */ 454 if (obj_main->interp != NULL && 455 strcmp(obj_main->interp, obj_rtld.path) != 0) { 456 free(obj_rtld.path); 457 obj_rtld.path = xstrdup(obj_main->interp); 458 __progname = obj_rtld.path; 459 } 460 461 digest_dynamic(obj_main, 0); 462 463 linkmap_add(obj_main); 464 linkmap_add(&obj_rtld); 465 466 /* Link the main program into the list of objects. */ 467 *obj_tail = obj_main; 468 obj_tail = &obj_main->next; 469 obj_count++; 470 obj_loads++; 471 /* Make sure we don't call the main program's init and fini functions. */ 472 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 473 474 /* Initialize a fake symbol for resolving undefined weak references. */ 475 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 476 sym_zero.st_shndx = SHN_UNDEF; 477 478 if (!libmap_disable) 479 libmap_disable = (bool)lm_init(libmap_override); 480 481 dbg("loading LD_PRELOAD libraries"); 482 if (load_preload_objects() == -1) 483 die(); 484 preload_tail = obj_tail; 485 486 dbg("loading needed objects"); 487 if (load_needed_objects(obj_main) == -1) 488 die(); 489 490 /* Make a list of all objects loaded at startup. */ 491 for (obj = obj_list; obj != NULL; obj = obj->next) { 492 objlist_push_tail(&list_main, obj); 493 obj->refcount++; 494 } 495 496 dbg("checking for required versions"); 497 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 498 die(); 499 500 if (ld_tracing) { /* We're done */ 501 trace_loaded_objects(obj_main); 502 exit(0); 503 } 504 505 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 506 dump_relocations(obj_main); 507 exit (0); 508 } 509 510 /* setup TLS for main thread */ 511 dbg("initializing initial thread local storage"); 512 STAILQ_FOREACH(entry, &list_main, link) { 513 /* 514 * Allocate all the initial objects out of the static TLS 515 * block even if they didn't ask for it. 516 */ 517 allocate_tls_offset(entry->obj); 518 } 519 allocate_initial_tls(obj_list); 520 521 if (relocate_objects(obj_main, 522 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 523 die(); 524 525 dbg("doing copy relocations"); 526 if (do_copy_relocations(obj_main) == -1) 527 die(); 528 529 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 530 dump_relocations(obj_main); 531 exit (0); 532 } 533 534 dbg("initializing key program variables"); 535 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 536 set_program_var("environ", env); 537 538 dbg("initializing thread locks"); 539 lockdflt_init(); 540 541 /* Make a list of init functions to call. */ 542 objlist_init(&initlist); 543 initlist_add_objects(obj_list, preload_tail, &initlist); 544 545 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 546 547 lockstate = wlock_acquire(rtld_bind_lock); 548 objlist_call_init(&initlist, &lockstate); 549 objlist_clear(&initlist); 550 wlock_release(rtld_bind_lock, lockstate); 551 552 dbg("transferring control to program entry point = %p", obj_main->entry); 553 554 /* Return the exit procedure and the program entry point. */ 555 *exit_proc = rtld_exit; 556 *objp = obj_main; 557 return (func_ptr_type) obj_main->entry; 558 } 559 560 Elf_Addr 561 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 562 { 563 const Elf_Rel *rel; 564 const Elf_Sym *def; 565 const Obj_Entry *defobj; 566 Elf_Addr *where; 567 Elf_Addr target; 568 int lockstate; 569 570 lockstate = rlock_acquire(rtld_bind_lock); 571 if (obj->pltrel) 572 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 573 else 574 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 575 576 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 577 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 578 if (def == NULL) 579 die(); 580 581 target = (Elf_Addr)(defobj->relocbase + def->st_value); 582 583 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 584 defobj->strtab + def->st_name, basename(obj->path), 585 (void *)target, basename(defobj->path)); 586 587 /* 588 * Write the new contents for the jmpslot. Note that depending on 589 * architecture, the value which we need to return back to the 590 * lazy binding trampoline may or may not be the target 591 * address. The value returned from reloc_jmpslot() is the value 592 * that the trampoline needs. 593 */ 594 target = reloc_jmpslot(where, target, defobj, obj, rel); 595 rlock_release(rtld_bind_lock, lockstate); 596 return target; 597 } 598 599 /* 600 * Error reporting function. Use it like printf. If formats the message 601 * into a buffer, and sets things up so that the next call to dlerror() 602 * will return the message. 603 */ 604 void 605 _rtld_error(const char *fmt, ...) 606 { 607 static char buf[512]; 608 va_list ap; 609 610 va_start(ap, fmt); 611 vsnprintf(buf, sizeof buf, fmt, ap); 612 error_message = buf; 613 va_end(ap); 614 } 615 616 /* 617 * Return a dynamically-allocated copy of the current error message, if any. 618 */ 619 static char * 620 errmsg_save(void) 621 { 622 return error_message == NULL ? NULL : xstrdup(error_message); 623 } 624 625 /* 626 * Restore the current error message from a copy which was previously saved 627 * by errmsg_save(). The copy is freed. 628 */ 629 static void 630 errmsg_restore(char *saved_msg) 631 { 632 if (saved_msg == NULL) 633 error_message = NULL; 634 else { 635 _rtld_error("%s", saved_msg); 636 free(saved_msg); 637 } 638 } 639 640 static const char * 641 basename(const char *name) 642 { 643 const char *p = strrchr(name, '/'); 644 return p != NULL ? p + 1 : name; 645 } 646 647 static struct utsname uts; 648 649 static int 650 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 651 char *may_free) 652 { 653 const char *p, *p1; 654 char *res1; 655 int subst_len; 656 int kw_len; 657 658 res1 = *res = NULL; 659 p = real; 660 subst_len = kw_len = 0; 661 for (;;) { 662 p1 = strstr(p, kw); 663 if (p1 != NULL) { 664 if (subst_len == 0) { 665 subst_len = strlen(subst); 666 kw_len = strlen(kw); 667 } 668 if (*res == NULL) { 669 *res = xmalloc(PATH_MAX); 670 res1 = *res; 671 } 672 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 673 _rtld_error("Substitution of %s in %s cannot be performed", 674 kw, real); 675 if (may_free != NULL) 676 free(may_free); 677 free(res); 678 return (false); 679 } 680 memcpy(res1, p, p1 - p); 681 res1 += p1 - p; 682 memcpy(res1, subst, subst_len); 683 res1 += subst_len; 684 p = p1 + kw_len; 685 } else { 686 if (*res == NULL) { 687 if (may_free != NULL) 688 *res = may_free; 689 else 690 *res = xstrdup(real); 691 return (true); 692 } 693 *res1 = '\0'; 694 if (may_free != NULL) 695 free(may_free); 696 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 697 free(res); 698 return (false); 699 } 700 return (true); 701 } 702 } 703 } 704 705 static char * 706 origin_subst(const char *real, const char *origin_path) 707 { 708 char *res1, *res2, *res3, *res4; 709 710 if (uts.sysname[0] == '\0') { 711 if (uname(&uts) != 0) { 712 _rtld_error("utsname failed: %d", errno); 713 return (NULL); 714 } 715 } 716 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 717 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 718 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 719 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 720 return (NULL); 721 return (res4); 722 } 723 724 static void 725 die(void) 726 { 727 const char *msg = dlerror(); 728 729 if (msg == NULL) 730 msg = "Fatal error"; 731 errx(1, "%s", msg); 732 } 733 734 /* 735 * Process a shared object's DYNAMIC section, and save the important 736 * information in its Obj_Entry structure. 737 */ 738 static void 739 digest_dynamic(Obj_Entry *obj, int early) 740 { 741 const Elf_Dyn *dynp; 742 Needed_Entry **needed_tail = &obj->needed; 743 const Elf_Dyn *dyn_rpath = NULL; 744 const Elf_Dyn *dyn_soname = NULL; 745 int plttype = DT_REL; 746 747 obj->bind_now = false; 748 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 749 switch (dynp->d_tag) { 750 751 case DT_REL: 752 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 753 break; 754 755 case DT_RELSZ: 756 obj->relsize = dynp->d_un.d_val; 757 break; 758 759 case DT_RELENT: 760 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 761 break; 762 763 case DT_JMPREL: 764 obj->pltrel = (const Elf_Rel *) 765 (obj->relocbase + dynp->d_un.d_ptr); 766 break; 767 768 case DT_PLTRELSZ: 769 obj->pltrelsize = dynp->d_un.d_val; 770 break; 771 772 case DT_RELA: 773 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 774 break; 775 776 case DT_RELASZ: 777 obj->relasize = dynp->d_un.d_val; 778 break; 779 780 case DT_RELAENT: 781 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 782 break; 783 784 case DT_PLTREL: 785 plttype = dynp->d_un.d_val; 786 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 787 break; 788 789 case DT_SYMTAB: 790 obj->symtab = (const Elf_Sym *) 791 (obj->relocbase + dynp->d_un.d_ptr); 792 break; 793 794 case DT_SYMENT: 795 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 796 break; 797 798 case DT_STRTAB: 799 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 800 break; 801 802 case DT_STRSZ: 803 obj->strsize = dynp->d_un.d_val; 804 break; 805 806 case DT_VERNEED: 807 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 808 dynp->d_un.d_val); 809 break; 810 811 case DT_VERNEEDNUM: 812 obj->verneednum = dynp->d_un.d_val; 813 break; 814 815 case DT_VERDEF: 816 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 817 dynp->d_un.d_val); 818 break; 819 820 case DT_VERDEFNUM: 821 obj->verdefnum = dynp->d_un.d_val; 822 break; 823 824 case DT_VERSYM: 825 obj->versyms = (const Elf_Versym *)(obj->relocbase + 826 dynp->d_un.d_val); 827 break; 828 829 case DT_HASH: 830 { 831 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 832 (obj->relocbase + dynp->d_un.d_ptr); 833 obj->nbuckets = hashtab[0]; 834 obj->nchains = hashtab[1]; 835 obj->buckets = hashtab + 2; 836 obj->chains = obj->buckets + obj->nbuckets; 837 } 838 break; 839 840 case DT_NEEDED: 841 if (!obj->rtld) { 842 Needed_Entry *nep = NEW(Needed_Entry); 843 nep->name = dynp->d_un.d_val; 844 nep->obj = NULL; 845 nep->next = NULL; 846 847 *needed_tail = nep; 848 needed_tail = &nep->next; 849 } 850 break; 851 852 case DT_PLTGOT: 853 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 854 break; 855 856 case DT_TEXTREL: 857 obj->textrel = true; 858 break; 859 860 case DT_SYMBOLIC: 861 obj->symbolic = true; 862 break; 863 864 case DT_RPATH: 865 case DT_RUNPATH: /* XXX: process separately */ 866 /* 867 * We have to wait until later to process this, because we 868 * might not have gotten the address of the string table yet. 869 */ 870 dyn_rpath = dynp; 871 break; 872 873 case DT_SONAME: 874 dyn_soname = dynp; 875 break; 876 877 case DT_INIT: 878 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 879 break; 880 881 case DT_FINI: 882 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 883 break; 884 885 /* 886 * Don't process DT_DEBUG on MIPS as the dynamic section 887 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 888 */ 889 890 #ifndef __mips__ 891 case DT_DEBUG: 892 /* XXX - not implemented yet */ 893 if (!early) 894 dbg("Filling in DT_DEBUG entry"); 895 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 896 break; 897 #endif 898 899 case DT_FLAGS: 900 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 901 obj->z_origin = true; 902 if (dynp->d_un.d_val & DF_SYMBOLIC) 903 obj->symbolic = true; 904 if (dynp->d_un.d_val & DF_TEXTREL) 905 obj->textrel = true; 906 if (dynp->d_un.d_val & DF_BIND_NOW) 907 obj->bind_now = true; 908 if (dynp->d_un.d_val & DF_STATIC_TLS) 909 ; 910 break; 911 #ifdef __mips__ 912 case DT_MIPS_LOCAL_GOTNO: 913 obj->local_gotno = dynp->d_un.d_val; 914 break; 915 916 case DT_MIPS_SYMTABNO: 917 obj->symtabno = dynp->d_un.d_val; 918 break; 919 920 case DT_MIPS_GOTSYM: 921 obj->gotsym = dynp->d_un.d_val; 922 break; 923 924 case DT_MIPS_RLD_MAP: 925 #ifdef notyet 926 if (!early) 927 dbg("Filling in DT_DEBUG entry"); 928 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 929 #endif 930 break; 931 #endif 932 933 case DT_FLAGS_1: 934 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 935 obj->z_origin = true; 936 if (dynp->d_un.d_val & DF_1_GLOBAL) 937 /* XXX */; 938 if (dynp->d_un.d_val & DF_1_BIND_NOW) 939 obj->bind_now = true; 940 break; 941 942 default: 943 if (!early) { 944 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 945 (long)dynp->d_tag); 946 } 947 break; 948 } 949 } 950 951 obj->traced = false; 952 953 if (plttype == DT_RELA) { 954 obj->pltrela = (const Elf_Rela *) obj->pltrel; 955 obj->pltrel = NULL; 956 obj->pltrelasize = obj->pltrelsize; 957 obj->pltrelsize = 0; 958 } 959 960 if (obj->z_origin && obj->origin_path == NULL) { 961 obj->origin_path = xmalloc(PATH_MAX); 962 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 963 die(); 964 } 965 966 if (dyn_rpath != NULL) { 967 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 968 if (obj->z_origin) 969 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 970 } 971 972 if (dyn_soname != NULL) 973 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 974 } 975 976 /* 977 * Process a shared object's program header. This is used only for the 978 * main program, when the kernel has already loaded the main program 979 * into memory before calling the dynamic linker. It creates and 980 * returns an Obj_Entry structure. 981 */ 982 static Obj_Entry * 983 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 984 { 985 Obj_Entry *obj; 986 const Elf_Phdr *phlimit = phdr + phnum; 987 const Elf_Phdr *ph; 988 int nsegs = 0; 989 990 obj = obj_new(); 991 for (ph = phdr; ph < phlimit; ph++) { 992 switch (ph->p_type) { 993 994 case PT_PHDR: 995 if ((const Elf_Phdr *)ph->p_vaddr != phdr) { 996 _rtld_error("%s: invalid PT_PHDR", path); 997 return NULL; 998 } 999 obj->phdr = (const Elf_Phdr *) ph->p_vaddr; 1000 obj->phsize = ph->p_memsz; 1001 break; 1002 1003 case PT_INTERP: 1004 obj->interp = (const char *) ph->p_vaddr; 1005 break; 1006 1007 case PT_LOAD: 1008 if (nsegs == 0) { /* First load segment */ 1009 obj->vaddrbase = trunc_page(ph->p_vaddr); 1010 obj->mapbase = (caddr_t) obj->vaddrbase; 1011 obj->relocbase = obj->mapbase - obj->vaddrbase; 1012 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1013 obj->vaddrbase; 1014 } else { /* Last load segment */ 1015 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1016 obj->vaddrbase; 1017 } 1018 nsegs++; 1019 break; 1020 1021 case PT_DYNAMIC: 1022 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; 1023 break; 1024 1025 case PT_TLS: 1026 obj->tlsindex = 1; 1027 obj->tlssize = ph->p_memsz; 1028 obj->tlsalign = ph->p_align; 1029 obj->tlsinitsize = ph->p_filesz; 1030 obj->tlsinit = (void*) ph->p_vaddr; 1031 break; 1032 } 1033 } 1034 if (nsegs < 1) { 1035 _rtld_error("%s: too few PT_LOAD segments", path); 1036 return NULL; 1037 } 1038 1039 obj->entry = entry; 1040 return obj; 1041 } 1042 1043 static Obj_Entry * 1044 dlcheck(void *handle) 1045 { 1046 Obj_Entry *obj; 1047 1048 for (obj = obj_list; obj != NULL; obj = obj->next) 1049 if (obj == (Obj_Entry *) handle) 1050 break; 1051 1052 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1053 _rtld_error("Invalid shared object handle %p", handle); 1054 return NULL; 1055 } 1056 return obj; 1057 } 1058 1059 /* 1060 * If the given object is already in the donelist, return true. Otherwise 1061 * add the object to the list and return false. 1062 */ 1063 static bool 1064 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1065 { 1066 unsigned int i; 1067 1068 for (i = 0; i < dlp->num_used; i++) 1069 if (dlp->objs[i] == obj) 1070 return true; 1071 /* 1072 * Our donelist allocation should always be sufficient. But if 1073 * our threads locking isn't working properly, more shared objects 1074 * could have been loaded since we allocated the list. That should 1075 * never happen, but we'll handle it properly just in case it does. 1076 */ 1077 if (dlp->num_used < dlp->num_alloc) 1078 dlp->objs[dlp->num_used++] = obj; 1079 return false; 1080 } 1081 1082 /* 1083 * Hash function for symbol table lookup. Don't even think about changing 1084 * this. It is specified by the System V ABI. 1085 */ 1086 unsigned long 1087 elf_hash(const char *name) 1088 { 1089 const unsigned char *p = (const unsigned char *) name; 1090 unsigned long h = 0; 1091 unsigned long g; 1092 1093 while (*p != '\0') { 1094 h = (h << 4) + *p++; 1095 if ((g = h & 0xf0000000) != 0) 1096 h ^= g >> 24; 1097 h &= ~g; 1098 } 1099 return h; 1100 } 1101 1102 /* 1103 * Find the library with the given name, and return its full pathname. 1104 * The returned string is dynamically allocated. Generates an error 1105 * message and returns NULL if the library cannot be found. 1106 * 1107 * If the second argument is non-NULL, then it refers to an already- 1108 * loaded shared object, whose library search path will be searched. 1109 * 1110 * The search order is: 1111 * LD_LIBRARY_PATH 1112 * rpath in the referencing file 1113 * ldconfig hints 1114 * /lib:/usr/lib 1115 */ 1116 static char * 1117 find_library(const char *xname, const Obj_Entry *refobj) 1118 { 1119 char *pathname; 1120 char *name; 1121 1122 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1123 if (xname[0] != '/' && !trust) { 1124 _rtld_error("Absolute pathname required for shared object \"%s\"", 1125 xname); 1126 return NULL; 1127 } 1128 if (refobj->z_origin) 1129 return origin_subst(xname, refobj->origin_path); 1130 else 1131 return xstrdup(xname); 1132 } 1133 1134 if (libmap_disable || (refobj == NULL) || 1135 (name = lm_find(refobj->path, xname)) == NULL) 1136 name = (char *)xname; 1137 1138 dbg(" Searching for \"%s\"", name); 1139 1140 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1141 (refobj != NULL && 1142 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1143 (pathname = search_library_path(name, gethints())) != NULL || 1144 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1145 return pathname; 1146 1147 if(refobj != NULL && refobj->path != NULL) { 1148 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1149 name, basename(refobj->path)); 1150 } else { 1151 _rtld_error("Shared object \"%s\" not found", name); 1152 } 1153 return NULL; 1154 } 1155 1156 /* 1157 * Given a symbol number in a referencing object, find the corresponding 1158 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1159 * no definition was found. Returns a pointer to the Obj_Entry of the 1160 * defining object via the reference parameter DEFOBJ_OUT. 1161 */ 1162 const Elf_Sym * 1163 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1164 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1165 { 1166 const Elf_Sym *ref; 1167 const Elf_Sym *def; 1168 const Obj_Entry *defobj; 1169 const Ver_Entry *ventry; 1170 const char *name; 1171 unsigned long hash; 1172 1173 /* 1174 * If we have already found this symbol, get the information from 1175 * the cache. 1176 */ 1177 if (symnum >= refobj->nchains) 1178 return NULL; /* Bad object */ 1179 if (cache != NULL && cache[symnum].sym != NULL) { 1180 *defobj_out = cache[symnum].obj; 1181 return cache[symnum].sym; 1182 } 1183 1184 ref = refobj->symtab + symnum; 1185 name = refobj->strtab + ref->st_name; 1186 defobj = NULL; 1187 1188 /* 1189 * We don't have to do a full scale lookup if the symbol is local. 1190 * We know it will bind to the instance in this load module; to 1191 * which we already have a pointer (ie ref). By not doing a lookup, 1192 * we not only improve performance, but it also avoids unresolvable 1193 * symbols when local symbols are not in the hash table. This has 1194 * been seen with the ia64 toolchain. 1195 */ 1196 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1197 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1198 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1199 symnum); 1200 } 1201 ventry = fetch_ventry(refobj, symnum); 1202 hash = elf_hash(name); 1203 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1204 } else { 1205 def = ref; 1206 defobj = refobj; 1207 } 1208 1209 /* 1210 * If we found no definition and the reference is weak, treat the 1211 * symbol as having the value zero. 1212 */ 1213 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1214 def = &sym_zero; 1215 defobj = obj_main; 1216 } 1217 1218 if (def != NULL) { 1219 *defobj_out = defobj; 1220 /* Record the information in the cache to avoid subsequent lookups. */ 1221 if (cache != NULL) { 1222 cache[symnum].sym = def; 1223 cache[symnum].obj = defobj; 1224 } 1225 } else { 1226 if (refobj != &obj_rtld) 1227 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1228 } 1229 return def; 1230 } 1231 1232 /* 1233 * Return the search path from the ldconfig hints file, reading it if 1234 * necessary. Returns NULL if there are problems with the hints file, 1235 * or if the search path there is empty. 1236 */ 1237 static const char * 1238 gethints(void) 1239 { 1240 static char *hints; 1241 1242 if (hints == NULL) { 1243 int fd; 1244 struct elfhints_hdr hdr; 1245 char *p; 1246 1247 /* Keep from trying again in case the hints file is bad. */ 1248 hints = ""; 1249 1250 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1251 return NULL; 1252 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1253 hdr.magic != ELFHINTS_MAGIC || 1254 hdr.version != 1) { 1255 close(fd); 1256 return NULL; 1257 } 1258 p = xmalloc(hdr.dirlistlen + 1); 1259 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1260 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1261 free(p); 1262 close(fd); 1263 return NULL; 1264 } 1265 hints = p; 1266 close(fd); 1267 } 1268 return hints[0] != '\0' ? hints : NULL; 1269 } 1270 1271 static void 1272 init_dag(Obj_Entry *root) 1273 { 1274 DoneList donelist; 1275 1276 donelist_init(&donelist); 1277 init_dag1(root, root, &donelist); 1278 } 1279 1280 static void 1281 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1282 { 1283 const Needed_Entry *needed; 1284 1285 if (donelist_check(dlp, obj)) 1286 return; 1287 1288 obj->refcount++; 1289 objlist_push_tail(&obj->dldags, root); 1290 objlist_push_tail(&root->dagmembers, obj); 1291 for (needed = obj->needed; needed != NULL; needed = needed->next) 1292 if (needed->obj != NULL) 1293 init_dag1(root, needed->obj, dlp); 1294 } 1295 1296 /* 1297 * Initialize the dynamic linker. The argument is the address at which 1298 * the dynamic linker has been mapped into memory. The primary task of 1299 * this function is to relocate the dynamic linker. 1300 */ 1301 static void 1302 init_rtld(caddr_t mapbase) 1303 { 1304 Obj_Entry objtmp; /* Temporary rtld object */ 1305 1306 /* 1307 * Conjure up an Obj_Entry structure for the dynamic linker. 1308 * 1309 * The "path" member can't be initialized yet because string constatns 1310 * cannot yet be acessed. Below we will set it correctly. 1311 */ 1312 memset(&objtmp, 0, sizeof(objtmp)); 1313 objtmp.path = NULL; 1314 objtmp.rtld = true; 1315 objtmp.mapbase = mapbase; 1316 #ifdef PIC 1317 objtmp.relocbase = mapbase; 1318 #endif 1319 if (RTLD_IS_DYNAMIC()) { 1320 objtmp.dynamic = rtld_dynamic(&objtmp); 1321 digest_dynamic(&objtmp, 1); 1322 assert(objtmp.needed == NULL); 1323 #if !defined(__mips__) 1324 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1325 assert(!objtmp.textrel); 1326 #endif 1327 1328 /* 1329 * Temporarily put the dynamic linker entry into the object list, so 1330 * that symbols can be found. 1331 */ 1332 1333 relocate_objects(&objtmp, true, &objtmp); 1334 } 1335 1336 /* Initialize the object list. */ 1337 obj_tail = &obj_list; 1338 1339 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1340 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1341 1342 /* Replace the path with a dynamically allocated copy. */ 1343 obj_rtld.path = xstrdup(PATH_RTLD); 1344 1345 r_debug.r_brk = r_debug_state; 1346 r_debug.r_state = RT_CONSISTENT; 1347 } 1348 1349 /* 1350 * Add the init functions from a needed object list (and its recursive 1351 * needed objects) to "list". This is not used directly; it is a helper 1352 * function for initlist_add_objects(). The write lock must be held 1353 * when this function is called. 1354 */ 1355 static void 1356 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1357 { 1358 /* Recursively process the successor needed objects. */ 1359 if (needed->next != NULL) 1360 initlist_add_neededs(needed->next, list); 1361 1362 /* Process the current needed object. */ 1363 if (needed->obj != NULL) 1364 initlist_add_objects(needed->obj, &needed->obj->next, list); 1365 } 1366 1367 /* 1368 * Scan all of the DAGs rooted in the range of objects from "obj" to 1369 * "tail" and add their init functions to "list". This recurses over 1370 * the DAGs and ensure the proper init ordering such that each object's 1371 * needed libraries are initialized before the object itself. At the 1372 * same time, this function adds the objects to the global finalization 1373 * list "list_fini" in the opposite order. The write lock must be 1374 * held when this function is called. 1375 */ 1376 static void 1377 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1378 { 1379 if (obj->init_done) 1380 return; 1381 obj->init_done = true; 1382 1383 /* Recursively process the successor objects. */ 1384 if (&obj->next != tail) 1385 initlist_add_objects(obj->next, tail, list); 1386 1387 /* Recursively process the needed objects. */ 1388 if (obj->needed != NULL) 1389 initlist_add_neededs(obj->needed, list); 1390 1391 /* Add the object to the init list. */ 1392 if (obj->init != (Elf_Addr)NULL) 1393 objlist_push_tail(list, obj); 1394 1395 /* Add the object to the global fini list in the reverse order. */ 1396 if (obj->fini != (Elf_Addr)NULL) 1397 objlist_push_head(&list_fini, obj); 1398 } 1399 1400 #ifndef FPTR_TARGET 1401 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1402 #endif 1403 1404 static bool 1405 is_exported(const Elf_Sym *def) 1406 { 1407 Elf_Addr value; 1408 const func_ptr_type *p; 1409 1410 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1411 for (p = exports; *p != NULL; p++) 1412 if (FPTR_TARGET(*p) == value) 1413 return true; 1414 return false; 1415 } 1416 1417 /* 1418 * Given a shared object, traverse its list of needed objects, and load 1419 * each of them. Returns 0 on success. Generates an error message and 1420 * returns -1 on failure. 1421 */ 1422 static int 1423 load_needed_objects(Obj_Entry *first) 1424 { 1425 Obj_Entry *obj; 1426 1427 for (obj = first; obj != NULL; obj = obj->next) { 1428 Needed_Entry *needed; 1429 1430 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1431 needed->obj = load_object(obj->strtab + needed->name, obj); 1432 if (needed->obj == NULL && !ld_tracing) 1433 return -1; 1434 } 1435 } 1436 1437 return 0; 1438 } 1439 1440 static int 1441 load_preload_objects(void) 1442 { 1443 char *p = ld_preload; 1444 static const char delim[] = " \t:;"; 1445 1446 if (p == NULL) 1447 return 0; 1448 1449 p += strspn(p, delim); 1450 while (*p != '\0') { 1451 size_t len = strcspn(p, delim); 1452 char savech; 1453 1454 savech = p[len]; 1455 p[len] = '\0'; 1456 if (load_object(p, NULL) == NULL) 1457 return -1; /* XXX - cleanup */ 1458 p[len] = savech; 1459 p += len; 1460 p += strspn(p, delim); 1461 } 1462 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1463 return 0; 1464 } 1465 1466 /* 1467 * Load a shared object into memory, if it is not already loaded. 1468 * 1469 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1470 * on failure. 1471 */ 1472 static Obj_Entry * 1473 load_object(const char *name, const Obj_Entry *refobj) 1474 { 1475 Obj_Entry *obj; 1476 int fd = -1; 1477 struct stat sb; 1478 char *path; 1479 1480 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1481 if (object_match_name(obj, name)) 1482 return obj; 1483 1484 path = find_library(name, refobj); 1485 if (path == NULL) 1486 return NULL; 1487 1488 /* 1489 * If we didn't find a match by pathname, open the file and check 1490 * again by device and inode. This avoids false mismatches caused 1491 * by multiple links or ".." in pathnames. 1492 * 1493 * To avoid a race, we open the file and use fstat() rather than 1494 * using stat(). 1495 */ 1496 if ((fd = open(path, O_RDONLY)) == -1) { 1497 _rtld_error("Cannot open \"%s\"", path); 1498 free(path); 1499 return NULL; 1500 } 1501 if (fstat(fd, &sb) == -1) { 1502 _rtld_error("Cannot fstat \"%s\"", path); 1503 close(fd); 1504 free(path); 1505 return NULL; 1506 } 1507 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1508 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1509 close(fd); 1510 break; 1511 } 1512 } 1513 if (obj != NULL) { 1514 object_add_name(obj, name); 1515 free(path); 1516 close(fd); 1517 return obj; 1518 } 1519 1520 /* First use of this object, so we must map it in */ 1521 obj = do_load_object(fd, name, path, &sb); 1522 if (obj == NULL) 1523 free(path); 1524 close(fd); 1525 1526 return obj; 1527 } 1528 1529 static Obj_Entry * 1530 do_load_object(int fd, const char *name, char *path, struct stat *sbp) 1531 { 1532 Obj_Entry *obj; 1533 struct statfs fs; 1534 1535 /* 1536 * but first, make sure that environment variables haven't been 1537 * used to circumvent the noexec flag on a filesystem. 1538 */ 1539 if (dangerous_ld_env) { 1540 if (fstatfs(fd, &fs) != 0) { 1541 _rtld_error("Cannot fstatfs \"%s\"", path); 1542 return NULL; 1543 } 1544 if (fs.f_flags & MNT_NOEXEC) { 1545 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1546 return NULL; 1547 } 1548 } 1549 dbg("loading \"%s\"", path); 1550 obj = map_object(fd, path, sbp); 1551 if (obj == NULL) 1552 return NULL; 1553 1554 object_add_name(obj, name); 1555 obj->path = path; 1556 digest_dynamic(obj, 0); 1557 1558 *obj_tail = obj; 1559 obj_tail = &obj->next; 1560 obj_count++; 1561 obj_loads++; 1562 linkmap_add(obj); /* for GDB & dlinfo() */ 1563 1564 dbg(" %p .. %p: %s", obj->mapbase, 1565 obj->mapbase + obj->mapsize - 1, obj->path); 1566 if (obj->textrel) 1567 dbg(" WARNING: %s has impure text", obj->path); 1568 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1569 obj->path); 1570 1571 return obj; 1572 } 1573 1574 static Obj_Entry * 1575 obj_from_addr(const void *addr) 1576 { 1577 Obj_Entry *obj; 1578 1579 for (obj = obj_list; obj != NULL; obj = obj->next) { 1580 if (addr < (void *) obj->mapbase) 1581 continue; 1582 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1583 return obj; 1584 } 1585 return NULL; 1586 } 1587 1588 /* 1589 * Call the finalization functions for each of the objects in "list" 1590 * which are unreferenced. All of the objects are expected to have 1591 * non-NULL fini functions. 1592 */ 1593 static void 1594 objlist_call_fini(Objlist *list, int *lockstate) 1595 { 1596 Objlist_Entry *elm; 1597 char *saved_msg; 1598 1599 /* 1600 * Preserve the current error message since a fini function might 1601 * call into the dynamic linker and overwrite it. 1602 */ 1603 saved_msg = errmsg_save(); 1604 wlock_release(rtld_bind_lock, *lockstate); 1605 STAILQ_FOREACH(elm, list, link) { 1606 if (elm->obj->refcount == 0) { 1607 dbg("calling fini function for %s at %p", elm->obj->path, 1608 (void *)elm->obj->fini); 1609 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1610 elm->obj->path); 1611 call_initfini_pointer(elm->obj, elm->obj->fini); 1612 } 1613 } 1614 *lockstate = wlock_acquire(rtld_bind_lock); 1615 errmsg_restore(saved_msg); 1616 } 1617 1618 /* 1619 * Call the initialization functions for each of the objects in 1620 * "list". All of the objects are expected to have non-NULL init 1621 * functions. 1622 */ 1623 static void 1624 objlist_call_init(Objlist *list, int *lockstate) 1625 { 1626 Objlist_Entry *elm; 1627 char *saved_msg; 1628 1629 /* 1630 * Preserve the current error message since an init function might 1631 * call into the dynamic linker and overwrite it. 1632 */ 1633 saved_msg = errmsg_save(); 1634 wlock_release(rtld_bind_lock, *lockstate); 1635 STAILQ_FOREACH(elm, list, link) { 1636 dbg("calling init function for %s at %p", elm->obj->path, 1637 (void *)elm->obj->init); 1638 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1639 elm->obj->path); 1640 call_initfini_pointer(elm->obj, elm->obj->init); 1641 } 1642 *lockstate = wlock_acquire(rtld_bind_lock); 1643 errmsg_restore(saved_msg); 1644 } 1645 1646 static void 1647 objlist_clear(Objlist *list) 1648 { 1649 Objlist_Entry *elm; 1650 1651 while (!STAILQ_EMPTY(list)) { 1652 elm = STAILQ_FIRST(list); 1653 STAILQ_REMOVE_HEAD(list, link); 1654 free(elm); 1655 } 1656 } 1657 1658 static Objlist_Entry * 1659 objlist_find(Objlist *list, const Obj_Entry *obj) 1660 { 1661 Objlist_Entry *elm; 1662 1663 STAILQ_FOREACH(elm, list, link) 1664 if (elm->obj == obj) 1665 return elm; 1666 return NULL; 1667 } 1668 1669 static void 1670 objlist_init(Objlist *list) 1671 { 1672 STAILQ_INIT(list); 1673 } 1674 1675 static void 1676 objlist_push_head(Objlist *list, Obj_Entry *obj) 1677 { 1678 Objlist_Entry *elm; 1679 1680 elm = NEW(Objlist_Entry); 1681 elm->obj = obj; 1682 STAILQ_INSERT_HEAD(list, elm, link); 1683 } 1684 1685 static void 1686 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1687 { 1688 Objlist_Entry *elm; 1689 1690 elm = NEW(Objlist_Entry); 1691 elm->obj = obj; 1692 STAILQ_INSERT_TAIL(list, elm, link); 1693 } 1694 1695 static void 1696 objlist_remove(Objlist *list, Obj_Entry *obj) 1697 { 1698 Objlist_Entry *elm; 1699 1700 if ((elm = objlist_find(list, obj)) != NULL) { 1701 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1702 free(elm); 1703 } 1704 } 1705 1706 /* 1707 * Remove all of the unreferenced objects from "list". 1708 */ 1709 static void 1710 objlist_remove_unref(Objlist *list) 1711 { 1712 Objlist newlist; 1713 Objlist_Entry *elm; 1714 1715 STAILQ_INIT(&newlist); 1716 while (!STAILQ_EMPTY(list)) { 1717 elm = STAILQ_FIRST(list); 1718 STAILQ_REMOVE_HEAD(list, link); 1719 if (elm->obj->refcount == 0) 1720 free(elm); 1721 else 1722 STAILQ_INSERT_TAIL(&newlist, elm, link); 1723 } 1724 *list = newlist; 1725 } 1726 1727 /* 1728 * Relocate newly-loaded shared objects. The argument is a pointer to 1729 * the Obj_Entry for the first such object. All objects from the first 1730 * to the end of the list of objects are relocated. Returns 0 on success, 1731 * or -1 on failure. 1732 */ 1733 static int 1734 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1735 { 1736 Obj_Entry *obj; 1737 1738 for (obj = first; obj != NULL; obj = obj->next) { 1739 if (obj != rtldobj) 1740 dbg("relocating \"%s\"", obj->path); 1741 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1742 obj->symtab == NULL || obj->strtab == NULL) { 1743 _rtld_error("%s: Shared object has no run-time symbol table", 1744 obj->path); 1745 return -1; 1746 } 1747 1748 if (obj->textrel) { 1749 /* There are relocations to the write-protected text segment. */ 1750 if (mprotect(obj->mapbase, obj->textsize, 1751 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1752 _rtld_error("%s: Cannot write-enable text segment: %s", 1753 obj->path, strerror(errno)); 1754 return -1; 1755 } 1756 } 1757 1758 /* Process the non-PLT relocations. */ 1759 if (reloc_non_plt(obj, rtldobj)) 1760 return -1; 1761 1762 if (obj->textrel) { /* Re-protected the text segment. */ 1763 if (mprotect(obj->mapbase, obj->textsize, 1764 PROT_READ|PROT_EXEC) == -1) { 1765 _rtld_error("%s: Cannot write-protect text segment: %s", 1766 obj->path, strerror(errno)); 1767 return -1; 1768 } 1769 } 1770 1771 /* Process the PLT relocations. */ 1772 if (reloc_plt(obj) == -1) 1773 return -1; 1774 /* Relocate the jump slots if we are doing immediate binding. */ 1775 if (obj->bind_now || bind_now) 1776 if (reloc_jmpslots(obj) == -1) 1777 return -1; 1778 1779 1780 /* 1781 * Set up the magic number and version in the Obj_Entry. These 1782 * were checked in the crt1.o from the original ElfKit, so we 1783 * set them for backward compatibility. 1784 */ 1785 obj->magic = RTLD_MAGIC; 1786 obj->version = RTLD_VERSION; 1787 1788 /* Set the special PLT or GOT entries. */ 1789 init_pltgot(obj); 1790 } 1791 1792 return 0; 1793 } 1794 1795 /* 1796 * Cleanup procedure. It will be called (by the atexit mechanism) just 1797 * before the process exits. 1798 */ 1799 static void 1800 rtld_exit(void) 1801 { 1802 Obj_Entry *obj; 1803 int lockstate; 1804 1805 lockstate = wlock_acquire(rtld_bind_lock); 1806 dbg("rtld_exit()"); 1807 /* Clear all the reference counts so the fini functions will be called. */ 1808 for (obj = obj_list; obj != NULL; obj = obj->next) 1809 obj->refcount = 0; 1810 objlist_call_fini(&list_fini, &lockstate); 1811 /* No need to remove the items from the list, since we are exiting. */ 1812 if (!libmap_disable) 1813 lm_fini(); 1814 wlock_release(rtld_bind_lock, lockstate); 1815 } 1816 1817 static void * 1818 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1819 { 1820 #ifdef COMPAT_32BIT 1821 const char *trans; 1822 #endif 1823 if (path == NULL) 1824 return (NULL); 1825 1826 path += strspn(path, ":;"); 1827 while (*path != '\0') { 1828 size_t len; 1829 char *res; 1830 1831 len = strcspn(path, ":;"); 1832 #ifdef COMPAT_32BIT 1833 trans = lm_findn(NULL, path, len); 1834 if (trans) 1835 res = callback(trans, strlen(trans), arg); 1836 else 1837 #endif 1838 res = callback(path, len, arg); 1839 1840 if (res != NULL) 1841 return (res); 1842 1843 path += len; 1844 path += strspn(path, ":;"); 1845 } 1846 1847 return (NULL); 1848 } 1849 1850 struct try_library_args { 1851 const char *name; 1852 size_t namelen; 1853 char *buffer; 1854 size_t buflen; 1855 }; 1856 1857 static void * 1858 try_library_path(const char *dir, size_t dirlen, void *param) 1859 { 1860 struct try_library_args *arg; 1861 1862 arg = param; 1863 if (*dir == '/' || trust) { 1864 char *pathname; 1865 1866 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1867 return (NULL); 1868 1869 pathname = arg->buffer; 1870 strncpy(pathname, dir, dirlen); 1871 pathname[dirlen] = '/'; 1872 strcpy(pathname + dirlen + 1, arg->name); 1873 1874 dbg(" Trying \"%s\"", pathname); 1875 if (access(pathname, F_OK) == 0) { /* We found it */ 1876 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1877 strcpy(pathname, arg->buffer); 1878 return (pathname); 1879 } 1880 } 1881 return (NULL); 1882 } 1883 1884 static char * 1885 search_library_path(const char *name, const char *path) 1886 { 1887 char *p; 1888 struct try_library_args arg; 1889 1890 if (path == NULL) 1891 return NULL; 1892 1893 arg.name = name; 1894 arg.namelen = strlen(name); 1895 arg.buffer = xmalloc(PATH_MAX); 1896 arg.buflen = PATH_MAX; 1897 1898 p = path_enumerate(path, try_library_path, &arg); 1899 1900 free(arg.buffer); 1901 1902 return (p); 1903 } 1904 1905 int 1906 dlclose(void *handle) 1907 { 1908 Obj_Entry *root; 1909 int lockstate; 1910 1911 lockstate = wlock_acquire(rtld_bind_lock); 1912 root = dlcheck(handle); 1913 if (root == NULL) { 1914 wlock_release(rtld_bind_lock, lockstate); 1915 return -1; 1916 } 1917 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1918 root->path); 1919 1920 /* Unreference the object and its dependencies. */ 1921 root->dl_refcount--; 1922 1923 unref_dag(root); 1924 1925 if (root->refcount == 0) { 1926 /* 1927 * The object is no longer referenced, so we must unload it. 1928 * First, call the fini functions. 1929 */ 1930 objlist_call_fini(&list_fini, &lockstate); 1931 objlist_remove_unref(&list_fini); 1932 1933 /* Finish cleaning up the newly-unreferenced objects. */ 1934 GDB_STATE(RT_DELETE,&root->linkmap); 1935 unload_object(root); 1936 GDB_STATE(RT_CONSISTENT,NULL); 1937 } 1938 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1939 wlock_release(rtld_bind_lock, lockstate); 1940 return 0; 1941 } 1942 1943 const char * 1944 dlerror(void) 1945 { 1946 char *msg = error_message; 1947 error_message = NULL; 1948 return msg; 1949 } 1950 1951 /* 1952 * This function is deprecated and has no effect. 1953 */ 1954 void 1955 dllockinit(void *context, 1956 void *(*lock_create)(void *context), 1957 void (*rlock_acquire)(void *lock), 1958 void (*wlock_acquire)(void *lock), 1959 void (*lock_release)(void *lock), 1960 void (*lock_destroy)(void *lock), 1961 void (*context_destroy)(void *context)) 1962 { 1963 static void *cur_context; 1964 static void (*cur_context_destroy)(void *); 1965 1966 /* Just destroy the context from the previous call, if necessary. */ 1967 if (cur_context_destroy != NULL) 1968 cur_context_destroy(cur_context); 1969 cur_context = context; 1970 cur_context_destroy = context_destroy; 1971 } 1972 1973 void * 1974 dlopen(const char *name, int mode) 1975 { 1976 Obj_Entry **old_obj_tail; 1977 Obj_Entry *obj; 1978 Objlist initlist; 1979 int result, lockstate; 1980 1981 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 1982 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1983 if (ld_tracing != NULL) 1984 environ = (char **)*get_program_var_addr("environ"); 1985 1986 objlist_init(&initlist); 1987 1988 lockstate = wlock_acquire(rtld_bind_lock); 1989 GDB_STATE(RT_ADD,NULL); 1990 1991 old_obj_tail = obj_tail; 1992 obj = NULL; 1993 if (name == NULL) { 1994 obj = obj_main; 1995 obj->refcount++; 1996 } else { 1997 obj = load_object(name, obj_main); 1998 } 1999 2000 if (obj) { 2001 obj->dl_refcount++; 2002 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2003 objlist_push_tail(&list_global, obj); 2004 mode &= RTLD_MODEMASK; 2005 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2006 assert(*old_obj_tail == obj); 2007 result = load_needed_objects(obj); 2008 init_dag(obj); 2009 if (result != -1) 2010 result = rtld_verify_versions(&obj->dagmembers); 2011 if (result != -1 && ld_tracing) 2012 goto trace; 2013 if (result == -1 || 2014 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2015 obj->dl_refcount--; 2016 unref_dag(obj); 2017 if (obj->refcount == 0) 2018 unload_object(obj); 2019 obj = NULL; 2020 } else { 2021 /* Make list of init functions to call. */ 2022 initlist_add_objects(obj, &obj->next, &initlist); 2023 } 2024 } else { 2025 2026 /* Bump the reference counts for objects on this DAG. */ 2027 ref_dag(obj); 2028 2029 if (ld_tracing) 2030 goto trace; 2031 } 2032 } 2033 2034 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2035 name); 2036 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2037 2038 /* Call the init functions. */ 2039 objlist_call_init(&initlist, &lockstate); 2040 objlist_clear(&initlist); 2041 wlock_release(rtld_bind_lock, lockstate); 2042 return obj; 2043 trace: 2044 trace_loaded_objects(obj); 2045 wlock_release(rtld_bind_lock, lockstate); 2046 exit(0); 2047 } 2048 2049 static void * 2050 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2051 int flags) 2052 { 2053 DoneList donelist; 2054 const Obj_Entry *obj, *defobj; 2055 const Elf_Sym *def, *symp; 2056 unsigned long hash; 2057 int lockstate; 2058 2059 hash = elf_hash(name); 2060 def = NULL; 2061 defobj = NULL; 2062 flags |= SYMLOOK_IN_PLT; 2063 2064 lockstate = rlock_acquire(rtld_bind_lock); 2065 if (handle == NULL || handle == RTLD_NEXT || 2066 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2067 2068 if ((obj = obj_from_addr(retaddr)) == NULL) { 2069 _rtld_error("Cannot determine caller's shared object"); 2070 rlock_release(rtld_bind_lock, lockstate); 2071 return NULL; 2072 } 2073 if (handle == NULL) { /* Just the caller's shared object. */ 2074 def = symlook_obj(name, hash, obj, ve, flags); 2075 defobj = obj; 2076 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2077 handle == RTLD_SELF) { /* ... caller included */ 2078 if (handle == RTLD_NEXT) 2079 obj = obj->next; 2080 for (; obj != NULL; obj = obj->next) { 2081 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2082 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2083 def = symp; 2084 defobj = obj; 2085 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2086 break; 2087 } 2088 } 2089 } 2090 /* 2091 * Search the dynamic linker itself, and possibly resolve the 2092 * symbol from there. This is how the application links to 2093 * dynamic linker services such as dlopen. Only the values listed 2094 * in the "exports" array can be resolved from the dynamic linker. 2095 */ 2096 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2097 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2098 if (symp != NULL && is_exported(symp)) { 2099 def = symp; 2100 defobj = &obj_rtld; 2101 } 2102 } 2103 } else { 2104 assert(handle == RTLD_DEFAULT); 2105 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2106 } 2107 } else { 2108 if ((obj = dlcheck(handle)) == NULL) { 2109 rlock_release(rtld_bind_lock, lockstate); 2110 return NULL; 2111 } 2112 2113 donelist_init(&donelist); 2114 if (obj->mainprog) { 2115 /* Search main program and all libraries loaded by it. */ 2116 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2117 &donelist); 2118 } else { 2119 Needed_Entry fake; 2120 2121 /* Search the whole DAG rooted at the given object. */ 2122 fake.next = NULL; 2123 fake.obj = (Obj_Entry *)obj; 2124 fake.name = 0; 2125 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2126 &donelist); 2127 } 2128 } 2129 2130 if (def != NULL) { 2131 rlock_release(rtld_bind_lock, lockstate); 2132 2133 /* 2134 * The value required by the caller is derived from the value 2135 * of the symbol. For the ia64 architecture, we need to 2136 * construct a function descriptor which the caller can use to 2137 * call the function with the right 'gp' value. For other 2138 * architectures and for non-functions, the value is simply 2139 * the relocated value of the symbol. 2140 */ 2141 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2142 return make_function_pointer(def, defobj); 2143 else 2144 return defobj->relocbase + def->st_value; 2145 } 2146 2147 _rtld_error("Undefined symbol \"%s\"", name); 2148 rlock_release(rtld_bind_lock, lockstate); 2149 return NULL; 2150 } 2151 2152 void * 2153 dlsym(void *handle, const char *name) 2154 { 2155 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2156 SYMLOOK_DLSYM); 2157 } 2158 2159 void * 2160 dlvsym(void *handle, const char *name, const char *version) 2161 { 2162 Ver_Entry ventry; 2163 2164 ventry.name = version; 2165 ventry.file = NULL; 2166 ventry.hash = elf_hash(version); 2167 ventry.flags= 0; 2168 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2169 SYMLOOK_DLSYM); 2170 } 2171 2172 int 2173 dladdr(const void *addr, Dl_info *info) 2174 { 2175 const Obj_Entry *obj; 2176 const Elf_Sym *def; 2177 void *symbol_addr; 2178 unsigned long symoffset; 2179 int lockstate; 2180 2181 lockstate = rlock_acquire(rtld_bind_lock); 2182 obj = obj_from_addr(addr); 2183 if (obj == NULL) { 2184 _rtld_error("No shared object contains address"); 2185 rlock_release(rtld_bind_lock, lockstate); 2186 return 0; 2187 } 2188 info->dli_fname = obj->path; 2189 info->dli_fbase = obj->mapbase; 2190 info->dli_saddr = (void *)0; 2191 info->dli_sname = NULL; 2192 2193 /* 2194 * Walk the symbol list looking for the symbol whose address is 2195 * closest to the address sent in. 2196 */ 2197 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2198 def = obj->symtab + symoffset; 2199 2200 /* 2201 * For skip the symbol if st_shndx is either SHN_UNDEF or 2202 * SHN_COMMON. 2203 */ 2204 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2205 continue; 2206 2207 /* 2208 * If the symbol is greater than the specified address, or if it 2209 * is further away from addr than the current nearest symbol, 2210 * then reject it. 2211 */ 2212 symbol_addr = obj->relocbase + def->st_value; 2213 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2214 continue; 2215 2216 /* Update our idea of the nearest symbol. */ 2217 info->dli_sname = obj->strtab + def->st_name; 2218 info->dli_saddr = symbol_addr; 2219 2220 /* Exact match? */ 2221 if (info->dli_saddr == addr) 2222 break; 2223 } 2224 rlock_release(rtld_bind_lock, lockstate); 2225 return 1; 2226 } 2227 2228 int 2229 dlinfo(void *handle, int request, void *p) 2230 { 2231 const Obj_Entry *obj; 2232 int error, lockstate; 2233 2234 lockstate = rlock_acquire(rtld_bind_lock); 2235 2236 if (handle == NULL || handle == RTLD_SELF) { 2237 void *retaddr; 2238 2239 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2240 if ((obj = obj_from_addr(retaddr)) == NULL) 2241 _rtld_error("Cannot determine caller's shared object"); 2242 } else 2243 obj = dlcheck(handle); 2244 2245 if (obj == NULL) { 2246 rlock_release(rtld_bind_lock, lockstate); 2247 return (-1); 2248 } 2249 2250 error = 0; 2251 switch (request) { 2252 case RTLD_DI_LINKMAP: 2253 *((struct link_map const **)p) = &obj->linkmap; 2254 break; 2255 case RTLD_DI_ORIGIN: 2256 error = rtld_dirname(obj->path, p); 2257 break; 2258 2259 case RTLD_DI_SERINFOSIZE: 2260 case RTLD_DI_SERINFO: 2261 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2262 break; 2263 2264 default: 2265 _rtld_error("Invalid request %d passed to dlinfo()", request); 2266 error = -1; 2267 } 2268 2269 rlock_release(rtld_bind_lock, lockstate); 2270 2271 return (error); 2272 } 2273 2274 int 2275 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2276 { 2277 struct dl_phdr_info phdr_info; 2278 const Obj_Entry *obj; 2279 int error, bind_lockstate, phdr_lockstate; 2280 2281 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2282 bind_lockstate = rlock_acquire(rtld_bind_lock); 2283 2284 error = 0; 2285 2286 for (obj = obj_list; obj != NULL; obj = obj->next) { 2287 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2288 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2289 STAILQ_FIRST(&obj->names)->name : obj->path; 2290 phdr_info.dlpi_phdr = obj->phdr; 2291 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2292 phdr_info.dlpi_tls_modid = obj->tlsindex; 2293 phdr_info.dlpi_tls_data = obj->tlsinit; 2294 phdr_info.dlpi_adds = obj_loads; 2295 phdr_info.dlpi_subs = obj_loads - obj_count; 2296 2297 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2298 break; 2299 2300 } 2301 rlock_release(rtld_bind_lock, bind_lockstate); 2302 wlock_release(rtld_phdr_lock, phdr_lockstate); 2303 2304 return (error); 2305 } 2306 2307 struct fill_search_info_args { 2308 int request; 2309 unsigned int flags; 2310 Dl_serinfo *serinfo; 2311 Dl_serpath *serpath; 2312 char *strspace; 2313 }; 2314 2315 static void * 2316 fill_search_info(const char *dir, size_t dirlen, void *param) 2317 { 2318 struct fill_search_info_args *arg; 2319 2320 arg = param; 2321 2322 if (arg->request == RTLD_DI_SERINFOSIZE) { 2323 arg->serinfo->dls_cnt ++; 2324 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2325 } else { 2326 struct dl_serpath *s_entry; 2327 2328 s_entry = arg->serpath; 2329 s_entry->dls_name = arg->strspace; 2330 s_entry->dls_flags = arg->flags; 2331 2332 strncpy(arg->strspace, dir, dirlen); 2333 arg->strspace[dirlen] = '\0'; 2334 2335 arg->strspace += dirlen + 1; 2336 arg->serpath++; 2337 } 2338 2339 return (NULL); 2340 } 2341 2342 static int 2343 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2344 { 2345 struct dl_serinfo _info; 2346 struct fill_search_info_args args; 2347 2348 args.request = RTLD_DI_SERINFOSIZE; 2349 args.serinfo = &_info; 2350 2351 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2352 _info.dls_cnt = 0; 2353 2354 path_enumerate(ld_library_path, fill_search_info, &args); 2355 path_enumerate(obj->rpath, fill_search_info, &args); 2356 path_enumerate(gethints(), fill_search_info, &args); 2357 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2358 2359 2360 if (request == RTLD_DI_SERINFOSIZE) { 2361 info->dls_size = _info.dls_size; 2362 info->dls_cnt = _info.dls_cnt; 2363 return (0); 2364 } 2365 2366 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2367 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2368 return (-1); 2369 } 2370 2371 args.request = RTLD_DI_SERINFO; 2372 args.serinfo = info; 2373 args.serpath = &info->dls_serpath[0]; 2374 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2375 2376 args.flags = LA_SER_LIBPATH; 2377 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2378 return (-1); 2379 2380 args.flags = LA_SER_RUNPATH; 2381 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2382 return (-1); 2383 2384 args.flags = LA_SER_CONFIG; 2385 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2386 return (-1); 2387 2388 args.flags = LA_SER_DEFAULT; 2389 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2390 return (-1); 2391 return (0); 2392 } 2393 2394 static int 2395 rtld_dirname(const char *path, char *bname) 2396 { 2397 const char *endp; 2398 2399 /* Empty or NULL string gets treated as "." */ 2400 if (path == NULL || *path == '\0') { 2401 bname[0] = '.'; 2402 bname[1] = '\0'; 2403 return (0); 2404 } 2405 2406 /* Strip trailing slashes */ 2407 endp = path + strlen(path) - 1; 2408 while (endp > path && *endp == '/') 2409 endp--; 2410 2411 /* Find the start of the dir */ 2412 while (endp > path && *endp != '/') 2413 endp--; 2414 2415 /* Either the dir is "/" or there are no slashes */ 2416 if (endp == path) { 2417 bname[0] = *endp == '/' ? '/' : '.'; 2418 bname[1] = '\0'; 2419 return (0); 2420 } else { 2421 do { 2422 endp--; 2423 } while (endp > path && *endp == '/'); 2424 } 2425 2426 if (endp - path + 2 > PATH_MAX) 2427 { 2428 _rtld_error("Filename is too long: %s", path); 2429 return(-1); 2430 } 2431 2432 strncpy(bname, path, endp - path + 1); 2433 bname[endp - path + 1] = '\0'; 2434 return (0); 2435 } 2436 2437 static int 2438 rtld_dirname_abs(const char *path, char *base) 2439 { 2440 char base_rel[PATH_MAX]; 2441 2442 if (rtld_dirname(path, base) == -1) 2443 return (-1); 2444 if (base[0] == '/') 2445 return (0); 2446 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2447 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2448 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2449 return (-1); 2450 strcpy(base, base_rel); 2451 return (0); 2452 } 2453 2454 static void 2455 linkmap_add(Obj_Entry *obj) 2456 { 2457 struct link_map *l = &obj->linkmap; 2458 struct link_map *prev; 2459 2460 obj->linkmap.l_name = obj->path; 2461 obj->linkmap.l_addr = obj->mapbase; 2462 obj->linkmap.l_ld = obj->dynamic; 2463 #ifdef __mips__ 2464 /* GDB needs load offset on MIPS to use the symbols */ 2465 obj->linkmap.l_offs = obj->relocbase; 2466 #endif 2467 2468 if (r_debug.r_map == NULL) { 2469 r_debug.r_map = l; 2470 return; 2471 } 2472 2473 /* 2474 * Scan to the end of the list, but not past the entry for the 2475 * dynamic linker, which we want to keep at the very end. 2476 */ 2477 for (prev = r_debug.r_map; 2478 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2479 prev = prev->l_next) 2480 ; 2481 2482 /* Link in the new entry. */ 2483 l->l_prev = prev; 2484 l->l_next = prev->l_next; 2485 if (l->l_next != NULL) 2486 l->l_next->l_prev = l; 2487 prev->l_next = l; 2488 } 2489 2490 static void 2491 linkmap_delete(Obj_Entry *obj) 2492 { 2493 struct link_map *l = &obj->linkmap; 2494 2495 if (l->l_prev == NULL) { 2496 if ((r_debug.r_map = l->l_next) != NULL) 2497 l->l_next->l_prev = NULL; 2498 return; 2499 } 2500 2501 if ((l->l_prev->l_next = l->l_next) != NULL) 2502 l->l_next->l_prev = l->l_prev; 2503 } 2504 2505 /* 2506 * Function for the debugger to set a breakpoint on to gain control. 2507 * 2508 * The two parameters allow the debugger to easily find and determine 2509 * what the runtime loader is doing and to whom it is doing it. 2510 * 2511 * When the loadhook trap is hit (r_debug_state, set at program 2512 * initialization), the arguments can be found on the stack: 2513 * 2514 * +8 struct link_map *m 2515 * +4 struct r_debug *rd 2516 * +0 RetAddr 2517 */ 2518 void 2519 r_debug_state(struct r_debug* rd, struct link_map *m) 2520 { 2521 } 2522 2523 /* 2524 * Get address of the pointer variable in the main program. 2525 */ 2526 static const void ** 2527 get_program_var_addr(const char *name) 2528 { 2529 const Obj_Entry *obj; 2530 unsigned long hash; 2531 2532 hash = elf_hash(name); 2533 for (obj = obj_main; obj != NULL; obj = obj->next) { 2534 const Elf_Sym *def; 2535 2536 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2537 const void **addr; 2538 2539 addr = (const void **)(obj->relocbase + def->st_value); 2540 return addr; 2541 } 2542 } 2543 return NULL; 2544 } 2545 2546 /* 2547 * Set a pointer variable in the main program to the given value. This 2548 * is used to set key variables such as "environ" before any of the 2549 * init functions are called. 2550 */ 2551 static void 2552 set_program_var(const char *name, const void *value) 2553 { 2554 const void **addr; 2555 2556 if ((addr = get_program_var_addr(name)) != NULL) { 2557 dbg("\"%s\": *%p <-- %p", name, addr, value); 2558 *addr = value; 2559 } 2560 } 2561 2562 /* 2563 * Given a symbol name in a referencing object, find the corresponding 2564 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2565 * no definition was found. Returns a pointer to the Obj_Entry of the 2566 * defining object via the reference parameter DEFOBJ_OUT. 2567 */ 2568 static const Elf_Sym * 2569 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2570 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2571 { 2572 DoneList donelist; 2573 const Elf_Sym *def; 2574 const Elf_Sym *symp; 2575 const Obj_Entry *obj; 2576 const Obj_Entry *defobj; 2577 const Objlist_Entry *elm; 2578 def = NULL; 2579 defobj = NULL; 2580 donelist_init(&donelist); 2581 2582 /* Look first in the referencing object if linked symbolically. */ 2583 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2584 symp = symlook_obj(name, hash, refobj, ventry, flags); 2585 if (symp != NULL) { 2586 def = symp; 2587 defobj = refobj; 2588 } 2589 } 2590 2591 /* Search all objects loaded at program start up. */ 2592 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2593 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2594 &donelist); 2595 if (symp != NULL && 2596 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2597 def = symp; 2598 defobj = obj; 2599 } 2600 } 2601 2602 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2603 STAILQ_FOREACH(elm, &list_global, link) { 2604 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2605 break; 2606 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2607 flags, &donelist); 2608 if (symp != NULL && 2609 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2610 def = symp; 2611 defobj = obj; 2612 } 2613 } 2614 2615 /* Search all dlopened DAGs containing the referencing object. */ 2616 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2617 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2618 break; 2619 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2620 flags, &donelist); 2621 if (symp != NULL && 2622 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2623 def = symp; 2624 defobj = obj; 2625 } 2626 } 2627 2628 /* 2629 * Search the dynamic linker itself, and possibly resolve the 2630 * symbol from there. This is how the application links to 2631 * dynamic linker services such as dlopen. Only the values listed 2632 * in the "exports" array can be resolved from the dynamic linker. 2633 */ 2634 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2635 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2636 if (symp != NULL && is_exported(symp)) { 2637 def = symp; 2638 defobj = &obj_rtld; 2639 } 2640 } 2641 2642 if (def != NULL) 2643 *defobj_out = defobj; 2644 return def; 2645 } 2646 2647 static const Elf_Sym * 2648 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2649 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2650 DoneList *dlp) 2651 { 2652 const Elf_Sym *symp; 2653 const Elf_Sym *def; 2654 const Obj_Entry *defobj; 2655 const Objlist_Entry *elm; 2656 2657 def = NULL; 2658 defobj = NULL; 2659 STAILQ_FOREACH(elm, objlist, link) { 2660 if (donelist_check(dlp, elm->obj)) 2661 continue; 2662 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2663 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2664 def = symp; 2665 defobj = elm->obj; 2666 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2667 break; 2668 } 2669 } 2670 } 2671 if (def != NULL) 2672 *defobj_out = defobj; 2673 return def; 2674 } 2675 2676 /* 2677 * Search the symbol table of a shared object and all objects needed 2678 * by it for a symbol of the given name. Search order is 2679 * breadth-first. Returns a pointer to the symbol, or NULL if no 2680 * definition was found. 2681 */ 2682 static const Elf_Sym * 2683 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2684 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2685 DoneList *dlp) 2686 { 2687 const Elf_Sym *def, *def_w; 2688 const Needed_Entry *n; 2689 const Obj_Entry *obj, *defobj, *defobj1; 2690 2691 def = def_w = NULL; 2692 defobj = NULL; 2693 for (n = needed; n != NULL; n = n->next) { 2694 if ((obj = n->obj) == NULL || 2695 donelist_check(dlp, obj) || 2696 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2697 continue; 2698 defobj = obj; 2699 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2700 *defobj_out = defobj; 2701 return (def); 2702 } 2703 } 2704 /* 2705 * There we come when either symbol definition is not found in 2706 * directly needed objects, or found symbol is weak. 2707 */ 2708 for (n = needed; n != NULL; n = n->next) { 2709 if ((obj = n->obj) == NULL) 2710 continue; 2711 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2712 ventry, flags, dlp); 2713 if (def_w == NULL) 2714 continue; 2715 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2716 def = def_w; 2717 defobj = defobj1; 2718 } 2719 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2720 break; 2721 } 2722 if (def != NULL) 2723 *defobj_out = defobj; 2724 return (def); 2725 } 2726 2727 /* 2728 * Search the symbol table of a single shared object for a symbol of 2729 * the given name and version, if requested. Returns a pointer to the 2730 * symbol, or NULL if no definition was found. 2731 * 2732 * The symbol's hash value is passed in for efficiency reasons; that 2733 * eliminates many recomputations of the hash value. 2734 */ 2735 const Elf_Sym * 2736 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2737 const Ver_Entry *ventry, int flags) 2738 { 2739 unsigned long symnum; 2740 const Elf_Sym *vsymp; 2741 Elf_Versym verndx; 2742 int vcount; 2743 2744 if (obj->buckets == NULL) 2745 return NULL; 2746 2747 vsymp = NULL; 2748 vcount = 0; 2749 symnum = obj->buckets[hash % obj->nbuckets]; 2750 2751 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2752 const Elf_Sym *symp; 2753 const char *strp; 2754 2755 if (symnum >= obj->nchains) 2756 return NULL; /* Bad object */ 2757 2758 symp = obj->symtab + symnum; 2759 strp = obj->strtab + symp->st_name; 2760 2761 switch (ELF_ST_TYPE(symp->st_info)) { 2762 case STT_FUNC: 2763 case STT_NOTYPE: 2764 case STT_OBJECT: 2765 if (symp->st_value == 0) 2766 continue; 2767 /* fallthrough */ 2768 case STT_TLS: 2769 if (symp->st_shndx != SHN_UNDEF) 2770 break; 2771 #ifndef __mips__ 2772 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2773 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2774 break; 2775 /* fallthrough */ 2776 #endif 2777 default: 2778 continue; 2779 } 2780 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2781 continue; 2782 2783 if (ventry == NULL) { 2784 if (obj->versyms != NULL) { 2785 verndx = VER_NDX(obj->versyms[symnum]); 2786 if (verndx > obj->vernum) { 2787 _rtld_error("%s: symbol %s references wrong version %d", 2788 obj->path, obj->strtab + symnum, verndx); 2789 continue; 2790 } 2791 /* 2792 * If we are not called from dlsym (i.e. this is a normal 2793 * relocation from unversioned binary, accept the symbol 2794 * immediately if it happens to have first version after 2795 * this shared object became versioned. Otherwise, if 2796 * symbol is versioned and not hidden, remember it. If it 2797 * is the only symbol with this name exported by the 2798 * shared object, it will be returned as a match at the 2799 * end of the function. If symbol is global (verndx < 2) 2800 * accept it unconditionally. 2801 */ 2802 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2803 return symp; 2804 else if (verndx >= VER_NDX_GIVEN) { 2805 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2806 if (vsymp == NULL) 2807 vsymp = symp; 2808 vcount ++; 2809 } 2810 continue; 2811 } 2812 } 2813 return symp; 2814 } else { 2815 if (obj->versyms == NULL) { 2816 if (object_match_name(obj, ventry->name)) { 2817 _rtld_error("%s: object %s should provide version %s for " 2818 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2819 obj->strtab + symnum); 2820 continue; 2821 } 2822 } else { 2823 verndx = VER_NDX(obj->versyms[symnum]); 2824 if (verndx > obj->vernum) { 2825 _rtld_error("%s: symbol %s references wrong version %d", 2826 obj->path, obj->strtab + symnum, verndx); 2827 continue; 2828 } 2829 if (obj->vertab[verndx].hash != ventry->hash || 2830 strcmp(obj->vertab[verndx].name, ventry->name)) { 2831 /* 2832 * Version does not match. Look if this is a global symbol 2833 * and if it is not hidden. If global symbol (verndx < 2) 2834 * is available, use it. Do not return symbol if we are 2835 * called by dlvsym, because dlvsym looks for a specific 2836 * version and default one is not what dlvsym wants. 2837 */ 2838 if ((flags & SYMLOOK_DLSYM) || 2839 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2840 (verndx >= VER_NDX_GIVEN)) 2841 continue; 2842 } 2843 } 2844 return symp; 2845 } 2846 } 2847 return (vcount == 1) ? vsymp : NULL; 2848 } 2849 2850 static void 2851 trace_loaded_objects(Obj_Entry *obj) 2852 { 2853 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2854 int c; 2855 2856 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2857 main_local = ""; 2858 2859 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2860 fmt1 = "\t%o => %p (%x)\n"; 2861 2862 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2863 fmt2 = "\t%o (%x)\n"; 2864 2865 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2866 2867 for (; obj; obj = obj->next) { 2868 Needed_Entry *needed; 2869 char *name, *path; 2870 bool is_lib; 2871 2872 if (list_containers && obj->needed != NULL) 2873 printf("%s:\n", obj->path); 2874 for (needed = obj->needed; needed; needed = needed->next) { 2875 if (needed->obj != NULL) { 2876 if (needed->obj->traced && !list_containers) 2877 continue; 2878 needed->obj->traced = true; 2879 path = needed->obj->path; 2880 } else 2881 path = "not found"; 2882 2883 name = (char *)obj->strtab + needed->name; 2884 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2885 2886 fmt = is_lib ? fmt1 : fmt2; 2887 while ((c = *fmt++) != '\0') { 2888 switch (c) { 2889 default: 2890 putchar(c); 2891 continue; 2892 case '\\': 2893 switch (c = *fmt) { 2894 case '\0': 2895 continue; 2896 case 'n': 2897 putchar('\n'); 2898 break; 2899 case 't': 2900 putchar('\t'); 2901 break; 2902 } 2903 break; 2904 case '%': 2905 switch (c = *fmt) { 2906 case '\0': 2907 continue; 2908 case '%': 2909 default: 2910 putchar(c); 2911 break; 2912 case 'A': 2913 printf("%s", main_local); 2914 break; 2915 case 'a': 2916 printf("%s", obj_main->path); 2917 break; 2918 case 'o': 2919 printf("%s", name); 2920 break; 2921 #if 0 2922 case 'm': 2923 printf("%d", sodp->sod_major); 2924 break; 2925 case 'n': 2926 printf("%d", sodp->sod_minor); 2927 break; 2928 #endif 2929 case 'p': 2930 printf("%s", path); 2931 break; 2932 case 'x': 2933 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2934 break; 2935 } 2936 break; 2937 } 2938 ++fmt; 2939 } 2940 } 2941 } 2942 } 2943 2944 /* 2945 * Unload a dlopened object and its dependencies from memory and from 2946 * our data structures. It is assumed that the DAG rooted in the 2947 * object has already been unreferenced, and that the object has a 2948 * reference count of 0. 2949 */ 2950 static void 2951 unload_object(Obj_Entry *root) 2952 { 2953 Obj_Entry *obj; 2954 Obj_Entry **linkp; 2955 2956 assert(root->refcount == 0); 2957 2958 /* 2959 * Pass over the DAG removing unreferenced objects from 2960 * appropriate lists. 2961 */ 2962 unlink_object(root); 2963 2964 /* Unmap all objects that are no longer referenced. */ 2965 linkp = &obj_list->next; 2966 while ((obj = *linkp) != NULL) { 2967 if (obj->refcount == 0) { 2968 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2969 obj->path); 2970 dbg("unloading \"%s\"", obj->path); 2971 munmap(obj->mapbase, obj->mapsize); 2972 linkmap_delete(obj); 2973 *linkp = obj->next; 2974 obj_count--; 2975 obj_free(obj); 2976 } else 2977 linkp = &obj->next; 2978 } 2979 obj_tail = linkp; 2980 } 2981 2982 static void 2983 unlink_object(Obj_Entry *root) 2984 { 2985 Objlist_Entry *elm; 2986 2987 if (root->refcount == 0) { 2988 /* Remove the object from the RTLD_GLOBAL list. */ 2989 objlist_remove(&list_global, root); 2990 2991 /* Remove the object from all objects' DAG lists. */ 2992 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2993 objlist_remove(&elm->obj->dldags, root); 2994 if (elm->obj != root) 2995 unlink_object(elm->obj); 2996 } 2997 } 2998 } 2999 3000 static void 3001 ref_dag(Obj_Entry *root) 3002 { 3003 Objlist_Entry *elm; 3004 3005 STAILQ_FOREACH(elm, &root->dagmembers, link) 3006 elm->obj->refcount++; 3007 } 3008 3009 static void 3010 unref_dag(Obj_Entry *root) 3011 { 3012 Objlist_Entry *elm; 3013 3014 STAILQ_FOREACH(elm, &root->dagmembers, link) 3015 elm->obj->refcount--; 3016 } 3017 3018 /* 3019 * Common code for MD __tls_get_addr(). 3020 */ 3021 void * 3022 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3023 { 3024 Elf_Addr* dtv = *dtvp; 3025 int lockstate; 3026 3027 /* Check dtv generation in case new modules have arrived */ 3028 if (dtv[0] != tls_dtv_generation) { 3029 Elf_Addr* newdtv; 3030 int to_copy; 3031 3032 lockstate = wlock_acquire(rtld_bind_lock); 3033 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3034 to_copy = dtv[1]; 3035 if (to_copy > tls_max_index) 3036 to_copy = tls_max_index; 3037 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3038 newdtv[0] = tls_dtv_generation; 3039 newdtv[1] = tls_max_index; 3040 free(dtv); 3041 wlock_release(rtld_bind_lock, lockstate); 3042 *dtvp = newdtv; 3043 } 3044 3045 /* Dynamically allocate module TLS if necessary */ 3046 if (!dtv[index + 1]) { 3047 /* Signal safe, wlock will block out signals. */ 3048 lockstate = wlock_acquire(rtld_bind_lock); 3049 if (!dtv[index + 1]) 3050 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3051 wlock_release(rtld_bind_lock, lockstate); 3052 } 3053 return (void*) (dtv[index + 1] + offset); 3054 } 3055 3056 /* XXX not sure what variants to use for arm. */ 3057 3058 #if defined(__ia64__) || defined(__powerpc__) 3059 3060 /* 3061 * Allocate Static TLS using the Variant I method. 3062 */ 3063 void * 3064 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3065 { 3066 Obj_Entry *obj; 3067 char *tcb; 3068 Elf_Addr **tls; 3069 Elf_Addr *dtv; 3070 Elf_Addr addr; 3071 int i; 3072 3073 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3074 return (oldtcb); 3075 3076 assert(tcbsize >= TLS_TCB_SIZE); 3077 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3078 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3079 3080 if (oldtcb != NULL) { 3081 memcpy(tls, oldtcb, tls_static_space); 3082 free(oldtcb); 3083 3084 /* Adjust the DTV. */ 3085 dtv = tls[0]; 3086 for (i = 0; i < dtv[1]; i++) { 3087 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3088 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3089 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3090 } 3091 } 3092 } else { 3093 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3094 tls[0] = dtv; 3095 dtv[0] = tls_dtv_generation; 3096 dtv[1] = tls_max_index; 3097 3098 for (obj = objs; obj; obj = obj->next) { 3099 if (obj->tlsoffset) { 3100 addr = (Elf_Addr)tls + obj->tlsoffset; 3101 memset((void*) (addr + obj->tlsinitsize), 3102 0, obj->tlssize - obj->tlsinitsize); 3103 if (obj->tlsinit) 3104 memcpy((void*) addr, obj->tlsinit, 3105 obj->tlsinitsize); 3106 dtv[obj->tlsindex + 1] = addr; 3107 } 3108 } 3109 } 3110 3111 return (tcb); 3112 } 3113 3114 void 3115 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3116 { 3117 Elf_Addr *dtv; 3118 Elf_Addr tlsstart, tlsend; 3119 int dtvsize, i; 3120 3121 assert(tcbsize >= TLS_TCB_SIZE); 3122 3123 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3124 tlsend = tlsstart + tls_static_space; 3125 3126 dtv = *(Elf_Addr **)tlsstart; 3127 dtvsize = dtv[1]; 3128 for (i = 0; i < dtvsize; i++) { 3129 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3130 free((void*)dtv[i+2]); 3131 } 3132 } 3133 free(dtv); 3134 free(tcb); 3135 } 3136 3137 #endif 3138 3139 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3140 defined(__arm__) || defined(__mips__) 3141 3142 /* 3143 * Allocate Static TLS using the Variant II method. 3144 */ 3145 void * 3146 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3147 { 3148 Obj_Entry *obj; 3149 size_t size; 3150 char *tls; 3151 Elf_Addr *dtv, *olddtv; 3152 Elf_Addr segbase, oldsegbase, addr; 3153 int i; 3154 3155 size = round(tls_static_space, tcbalign); 3156 3157 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3158 tls = calloc(1, size + tcbsize); 3159 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3160 3161 segbase = (Elf_Addr)(tls + size); 3162 ((Elf_Addr*)segbase)[0] = segbase; 3163 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3164 3165 dtv[0] = tls_dtv_generation; 3166 dtv[1] = tls_max_index; 3167 3168 if (oldtls) { 3169 /* 3170 * Copy the static TLS block over whole. 3171 */ 3172 oldsegbase = (Elf_Addr) oldtls; 3173 memcpy((void *)(segbase - tls_static_space), 3174 (const void *)(oldsegbase - tls_static_space), 3175 tls_static_space); 3176 3177 /* 3178 * If any dynamic TLS blocks have been created tls_get_addr(), 3179 * move them over. 3180 */ 3181 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3182 for (i = 0; i < olddtv[1]; i++) { 3183 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3184 dtv[i+2] = olddtv[i+2]; 3185 olddtv[i+2] = 0; 3186 } 3187 } 3188 3189 /* 3190 * We assume that this block was the one we created with 3191 * allocate_initial_tls(). 3192 */ 3193 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3194 } else { 3195 for (obj = objs; obj; obj = obj->next) { 3196 if (obj->tlsoffset) { 3197 addr = segbase - obj->tlsoffset; 3198 memset((void*) (addr + obj->tlsinitsize), 3199 0, obj->tlssize - obj->tlsinitsize); 3200 if (obj->tlsinit) 3201 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3202 dtv[obj->tlsindex + 1] = addr; 3203 } 3204 } 3205 } 3206 3207 return (void*) segbase; 3208 } 3209 3210 void 3211 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3212 { 3213 size_t size; 3214 Elf_Addr* dtv; 3215 int dtvsize, i; 3216 Elf_Addr tlsstart, tlsend; 3217 3218 /* 3219 * Figure out the size of the initial TLS block so that we can 3220 * find stuff which ___tls_get_addr() allocated dynamically. 3221 */ 3222 size = round(tls_static_space, tcbalign); 3223 3224 dtv = ((Elf_Addr**)tls)[1]; 3225 dtvsize = dtv[1]; 3226 tlsend = (Elf_Addr) tls; 3227 tlsstart = tlsend - size; 3228 for (i = 0; i < dtvsize; i++) { 3229 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3230 free((void*) dtv[i+2]); 3231 } 3232 } 3233 3234 free((void*) tlsstart); 3235 free((void*) dtv); 3236 } 3237 3238 #endif 3239 3240 /* 3241 * Allocate TLS block for module with given index. 3242 */ 3243 void * 3244 allocate_module_tls(int index) 3245 { 3246 Obj_Entry* obj; 3247 char* p; 3248 3249 for (obj = obj_list; obj; obj = obj->next) { 3250 if (obj->tlsindex == index) 3251 break; 3252 } 3253 if (!obj) { 3254 _rtld_error("Can't find module with TLS index %d", index); 3255 die(); 3256 } 3257 3258 p = malloc(obj->tlssize); 3259 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3260 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3261 3262 return p; 3263 } 3264 3265 bool 3266 allocate_tls_offset(Obj_Entry *obj) 3267 { 3268 size_t off; 3269 3270 if (obj->tls_done) 3271 return true; 3272 3273 if (obj->tlssize == 0) { 3274 obj->tls_done = true; 3275 return true; 3276 } 3277 3278 if (obj->tlsindex == 1) 3279 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3280 else 3281 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3282 obj->tlssize, obj->tlsalign); 3283 3284 /* 3285 * If we have already fixed the size of the static TLS block, we 3286 * must stay within that size. When allocating the static TLS, we 3287 * leave a small amount of space spare to be used for dynamically 3288 * loading modules which use static TLS. 3289 */ 3290 if (tls_static_space) { 3291 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3292 return false; 3293 } 3294 3295 tls_last_offset = obj->tlsoffset = off; 3296 tls_last_size = obj->tlssize; 3297 obj->tls_done = true; 3298 3299 return true; 3300 } 3301 3302 void 3303 free_tls_offset(Obj_Entry *obj) 3304 { 3305 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3306 defined(__arm__) || defined(__mips__) 3307 /* 3308 * If we were the last thing to allocate out of the static TLS 3309 * block, we give our space back to the 'allocator'. This is a 3310 * simplistic workaround to allow libGL.so.1 to be loaded and 3311 * unloaded multiple times. We only handle the Variant II 3312 * mechanism for now - this really needs a proper allocator. 3313 */ 3314 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3315 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3316 tls_last_offset -= obj->tlssize; 3317 tls_last_size = 0; 3318 } 3319 #endif 3320 } 3321 3322 void * 3323 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3324 { 3325 void *ret; 3326 int lockstate; 3327 3328 lockstate = wlock_acquire(rtld_bind_lock); 3329 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3330 wlock_release(rtld_bind_lock, lockstate); 3331 return (ret); 3332 } 3333 3334 void 3335 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3336 { 3337 int lockstate; 3338 3339 lockstate = wlock_acquire(rtld_bind_lock); 3340 free_tls(tcb, tcbsize, tcbalign); 3341 wlock_release(rtld_bind_lock, lockstate); 3342 } 3343 3344 static void 3345 object_add_name(Obj_Entry *obj, const char *name) 3346 { 3347 Name_Entry *entry; 3348 size_t len; 3349 3350 len = strlen(name); 3351 entry = malloc(sizeof(Name_Entry) + len); 3352 3353 if (entry != NULL) { 3354 strcpy(entry->name, name); 3355 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3356 } 3357 } 3358 3359 static int 3360 object_match_name(const Obj_Entry *obj, const char *name) 3361 { 3362 Name_Entry *entry; 3363 3364 STAILQ_FOREACH(entry, &obj->names, link) { 3365 if (strcmp(name, entry->name) == 0) 3366 return (1); 3367 } 3368 return (0); 3369 } 3370 3371 static Obj_Entry * 3372 locate_dependency(const Obj_Entry *obj, const char *name) 3373 { 3374 const Objlist_Entry *entry; 3375 const Needed_Entry *needed; 3376 3377 STAILQ_FOREACH(entry, &list_main, link) { 3378 if (object_match_name(entry->obj, name)) 3379 return entry->obj; 3380 } 3381 3382 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3383 if (needed->obj == NULL) 3384 continue; 3385 if (object_match_name(needed->obj, name)) 3386 return needed->obj; 3387 } 3388 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3389 obj->path, name); 3390 die(); 3391 } 3392 3393 static int 3394 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3395 const Elf_Vernaux *vna) 3396 { 3397 const Elf_Verdef *vd; 3398 const char *vername; 3399 3400 vername = refobj->strtab + vna->vna_name; 3401 vd = depobj->verdef; 3402 if (vd == NULL) { 3403 _rtld_error("%s: version %s required by %s not defined", 3404 depobj->path, vername, refobj->path); 3405 return (-1); 3406 } 3407 for (;;) { 3408 if (vd->vd_version != VER_DEF_CURRENT) { 3409 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3410 depobj->path, vd->vd_version); 3411 return (-1); 3412 } 3413 if (vna->vna_hash == vd->vd_hash) { 3414 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3415 ((char *)vd + vd->vd_aux); 3416 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3417 return (0); 3418 } 3419 if (vd->vd_next == 0) 3420 break; 3421 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3422 } 3423 if (vna->vna_flags & VER_FLG_WEAK) 3424 return (0); 3425 _rtld_error("%s: version %s required by %s not found", 3426 depobj->path, vername, refobj->path); 3427 return (-1); 3428 } 3429 3430 static int 3431 rtld_verify_object_versions(Obj_Entry *obj) 3432 { 3433 const Elf_Verneed *vn; 3434 const Elf_Verdef *vd; 3435 const Elf_Verdaux *vda; 3436 const Elf_Vernaux *vna; 3437 const Obj_Entry *depobj; 3438 int maxvernum, vernum; 3439 3440 maxvernum = 0; 3441 /* 3442 * Walk over defined and required version records and figure out 3443 * max index used by any of them. Do very basic sanity checking 3444 * while there. 3445 */ 3446 vn = obj->verneed; 3447 while (vn != NULL) { 3448 if (vn->vn_version != VER_NEED_CURRENT) { 3449 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3450 obj->path, vn->vn_version); 3451 return (-1); 3452 } 3453 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3454 for (;;) { 3455 vernum = VER_NEED_IDX(vna->vna_other); 3456 if (vernum > maxvernum) 3457 maxvernum = vernum; 3458 if (vna->vna_next == 0) 3459 break; 3460 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3461 } 3462 if (vn->vn_next == 0) 3463 break; 3464 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3465 } 3466 3467 vd = obj->verdef; 3468 while (vd != NULL) { 3469 if (vd->vd_version != VER_DEF_CURRENT) { 3470 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3471 obj->path, vd->vd_version); 3472 return (-1); 3473 } 3474 vernum = VER_DEF_IDX(vd->vd_ndx); 3475 if (vernum > maxvernum) 3476 maxvernum = vernum; 3477 if (vd->vd_next == 0) 3478 break; 3479 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3480 } 3481 3482 if (maxvernum == 0) 3483 return (0); 3484 3485 /* 3486 * Store version information in array indexable by version index. 3487 * Verify that object version requirements are satisfied along the 3488 * way. 3489 */ 3490 obj->vernum = maxvernum + 1; 3491 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3492 3493 vd = obj->verdef; 3494 while (vd != NULL) { 3495 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3496 vernum = VER_DEF_IDX(vd->vd_ndx); 3497 assert(vernum <= maxvernum); 3498 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3499 obj->vertab[vernum].hash = vd->vd_hash; 3500 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3501 obj->vertab[vernum].file = NULL; 3502 obj->vertab[vernum].flags = 0; 3503 } 3504 if (vd->vd_next == 0) 3505 break; 3506 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3507 } 3508 3509 vn = obj->verneed; 3510 while (vn != NULL) { 3511 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3512 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3513 for (;;) { 3514 if (check_object_provided_version(obj, depobj, vna)) 3515 return (-1); 3516 vernum = VER_NEED_IDX(vna->vna_other); 3517 assert(vernum <= maxvernum); 3518 obj->vertab[vernum].hash = vna->vna_hash; 3519 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3520 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3521 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3522 VER_INFO_HIDDEN : 0; 3523 if (vna->vna_next == 0) 3524 break; 3525 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3526 } 3527 if (vn->vn_next == 0) 3528 break; 3529 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3530 } 3531 return 0; 3532 } 3533 3534 static int 3535 rtld_verify_versions(const Objlist *objlist) 3536 { 3537 Objlist_Entry *entry; 3538 int rc; 3539 3540 rc = 0; 3541 STAILQ_FOREACH(entry, objlist, link) { 3542 /* 3543 * Skip dummy objects or objects that have their version requirements 3544 * already checked. 3545 */ 3546 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3547 continue; 3548 if (rtld_verify_object_versions(entry->obj) == -1) { 3549 rc = -1; 3550 if (ld_tracing == NULL) 3551 break; 3552 } 3553 } 3554 if (rc == 0 || ld_tracing != NULL) 3555 rc = rtld_verify_object_versions(&obj_rtld); 3556 return rc; 3557 } 3558 3559 const Ver_Entry * 3560 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3561 { 3562 Elf_Versym vernum; 3563 3564 if (obj->vertab) { 3565 vernum = VER_NDX(obj->versyms[symnum]); 3566 if (vernum >= obj->vernum) { 3567 _rtld_error("%s: symbol %s has wrong verneed value %d", 3568 obj->path, obj->strtab + symnum, vernum); 3569 } else if (obj->vertab[vernum].hash != 0) { 3570 return &obj->vertab[vernum]; 3571 } 3572 } 3573 return NULL; 3574 } 3575