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 *, bool, int *); 111 static void objlist_call_init(Objlist *, int *); 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 *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 120 static int rtld_dirname(const char *, char *); 121 static int rtld_dirname_abs(const char *, char *); 122 static void rtld_exit(void); 123 static char *search_library_path(const char *, const char *); 124 static const void **get_program_var_addr(const char *); 125 static void set_program_var(const char *, const void *); 126 static const Elf_Sym *symlook_default(const char *, unsigned long, 127 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 128 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 129 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 130 static const Elf_Sym *symlook_needed(const char *, unsigned long, 131 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 132 int, DoneList *); 133 static void trace_loaded_objects(Obj_Entry *); 134 static void unlink_object(Obj_Entry *); 135 static void unload_object(Obj_Entry *); 136 static void unref_dag(Obj_Entry *); 137 static void ref_dag(Obj_Entry *); 138 static int origin_subst_one(char **, const char *, const char *, 139 const char *, char *); 140 static char *origin_subst(const char *, const char *); 141 static int rtld_verify_versions(const Objlist *); 142 static int rtld_verify_object_versions(Obj_Entry *); 143 static void object_add_name(Obj_Entry *, const char *); 144 static int object_match_name(const Obj_Entry *, const char *); 145 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 146 147 void r_debug_state(struct r_debug *, struct link_map *); 148 149 /* 150 * Data declarations. 151 */ 152 static char *error_message; /* Message for dlerror(), or NULL */ 153 struct r_debug r_debug; /* for GDB; */ 154 static bool libmap_disable; /* Disable libmap */ 155 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 156 static bool trust; /* False for setuid and setgid programs */ 157 static bool dangerous_ld_env; /* True if environment variables have been 158 used to affect the libraries loaded */ 159 static char *ld_bind_now; /* Environment variable for immediate binding */ 160 static char *ld_debug; /* Environment variable for debugging */ 161 static char *ld_library_path; /* Environment variable for search path */ 162 static char *ld_preload; /* Environment variable for libraries to 163 load first */ 164 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 165 static char *ld_tracing; /* Called from ldd to print libs */ 166 static char *ld_utrace; /* Use utrace() to log events. */ 167 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 168 static Obj_Entry **obj_tail; /* Link field of last object in list */ 169 static Obj_Entry *obj_main; /* The main program shared object */ 170 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 171 static unsigned int obj_count; /* Number of objects in obj_list */ 172 static unsigned int obj_loads; /* Number of objects in obj_list */ 173 174 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 175 STAILQ_HEAD_INITIALIZER(list_global); 176 static Objlist list_main = /* Objects loaded at program startup */ 177 STAILQ_HEAD_INITIALIZER(list_main); 178 static Objlist list_fini = /* Objects needing fini() calls */ 179 STAILQ_HEAD_INITIALIZER(list_fini); 180 181 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 182 183 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 184 185 extern Elf_Dyn _DYNAMIC; 186 #pragma weak _DYNAMIC 187 #ifndef RTLD_IS_DYNAMIC 188 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 189 #endif 190 191 /* 192 * These are the functions the dynamic linker exports to application 193 * programs. They are the only symbols the dynamic linker is willing 194 * to export from itself. 195 */ 196 static func_ptr_type exports[] = { 197 (func_ptr_type) &_rtld_error, 198 (func_ptr_type) &dlclose, 199 (func_ptr_type) &dlerror, 200 (func_ptr_type) &dlopen, 201 (func_ptr_type) &dlsym, 202 (func_ptr_type) &dlfunc, 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 if (dynp->d_un.d_val & DF_1_NODELETE) 941 obj->z_nodelete = true; 942 break; 943 944 default: 945 if (!early) { 946 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 947 (long)dynp->d_tag); 948 } 949 break; 950 } 951 } 952 953 obj->traced = false; 954 955 if (plttype == DT_RELA) { 956 obj->pltrela = (const Elf_Rela *) obj->pltrel; 957 obj->pltrel = NULL; 958 obj->pltrelasize = obj->pltrelsize; 959 obj->pltrelsize = 0; 960 } 961 962 if (obj->z_origin && obj->origin_path == NULL) { 963 obj->origin_path = xmalloc(PATH_MAX); 964 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 965 die(); 966 } 967 968 if (dyn_rpath != NULL) { 969 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 970 if (obj->z_origin) 971 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 972 } 973 974 if (dyn_soname != NULL) 975 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 976 } 977 978 /* 979 * Process a shared object's program header. This is used only for the 980 * main program, when the kernel has already loaded the main program 981 * into memory before calling the dynamic linker. It creates and 982 * returns an Obj_Entry structure. 983 */ 984 static Obj_Entry * 985 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 986 { 987 Obj_Entry *obj; 988 const Elf_Phdr *phlimit = phdr + phnum; 989 const Elf_Phdr *ph; 990 int nsegs = 0; 991 992 obj = obj_new(); 993 for (ph = phdr; ph < phlimit; ph++) { 994 switch (ph->p_type) { 995 996 case PT_PHDR: 997 if ((const Elf_Phdr *)ph->p_vaddr != phdr) { 998 _rtld_error("%s: invalid PT_PHDR", path); 999 return NULL; 1000 } 1001 obj->phdr = (const Elf_Phdr *) ph->p_vaddr; 1002 obj->phsize = ph->p_memsz; 1003 break; 1004 1005 case PT_INTERP: 1006 obj->interp = (const char *) ph->p_vaddr; 1007 break; 1008 1009 case PT_LOAD: 1010 if (nsegs == 0) { /* First load segment */ 1011 obj->vaddrbase = trunc_page(ph->p_vaddr); 1012 obj->mapbase = (caddr_t) obj->vaddrbase; 1013 obj->relocbase = obj->mapbase - obj->vaddrbase; 1014 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1015 obj->vaddrbase; 1016 } else { /* Last load segment */ 1017 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1018 obj->vaddrbase; 1019 } 1020 nsegs++; 1021 break; 1022 1023 case PT_DYNAMIC: 1024 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; 1025 break; 1026 1027 case PT_TLS: 1028 obj->tlsindex = 1; 1029 obj->tlssize = ph->p_memsz; 1030 obj->tlsalign = ph->p_align; 1031 obj->tlsinitsize = ph->p_filesz; 1032 obj->tlsinit = (void*) ph->p_vaddr; 1033 break; 1034 } 1035 } 1036 if (nsegs < 1) { 1037 _rtld_error("%s: too few PT_LOAD segments", path); 1038 return NULL; 1039 } 1040 1041 obj->entry = entry; 1042 return obj; 1043 } 1044 1045 static Obj_Entry * 1046 dlcheck(void *handle) 1047 { 1048 Obj_Entry *obj; 1049 1050 for (obj = obj_list; obj != NULL; obj = obj->next) 1051 if (obj == (Obj_Entry *) handle) 1052 break; 1053 1054 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1055 _rtld_error("Invalid shared object handle %p", handle); 1056 return NULL; 1057 } 1058 return obj; 1059 } 1060 1061 /* 1062 * If the given object is already in the donelist, return true. Otherwise 1063 * add the object to the list and return false. 1064 */ 1065 static bool 1066 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1067 { 1068 unsigned int i; 1069 1070 for (i = 0; i < dlp->num_used; i++) 1071 if (dlp->objs[i] == obj) 1072 return true; 1073 /* 1074 * Our donelist allocation should always be sufficient. But if 1075 * our threads locking isn't working properly, more shared objects 1076 * could have been loaded since we allocated the list. That should 1077 * never happen, but we'll handle it properly just in case it does. 1078 */ 1079 if (dlp->num_used < dlp->num_alloc) 1080 dlp->objs[dlp->num_used++] = obj; 1081 return false; 1082 } 1083 1084 /* 1085 * Hash function for symbol table lookup. Don't even think about changing 1086 * this. It is specified by the System V ABI. 1087 */ 1088 unsigned long 1089 elf_hash(const char *name) 1090 { 1091 const unsigned char *p = (const unsigned char *) name; 1092 unsigned long h = 0; 1093 unsigned long g; 1094 1095 while (*p != '\0') { 1096 h = (h << 4) + *p++; 1097 if ((g = h & 0xf0000000) != 0) 1098 h ^= g >> 24; 1099 h &= ~g; 1100 } 1101 return h; 1102 } 1103 1104 /* 1105 * Find the library with the given name, and return its full pathname. 1106 * The returned string is dynamically allocated. Generates an error 1107 * message and returns NULL if the library cannot be found. 1108 * 1109 * If the second argument is non-NULL, then it refers to an already- 1110 * loaded shared object, whose library search path will be searched. 1111 * 1112 * The search order is: 1113 * LD_LIBRARY_PATH 1114 * rpath in the referencing file 1115 * ldconfig hints 1116 * /lib:/usr/lib 1117 */ 1118 static char * 1119 find_library(const char *xname, const Obj_Entry *refobj) 1120 { 1121 char *pathname; 1122 char *name; 1123 1124 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1125 if (xname[0] != '/' && !trust) { 1126 _rtld_error("Absolute pathname required for shared object \"%s\"", 1127 xname); 1128 return NULL; 1129 } 1130 if (refobj != NULL && refobj->z_origin) 1131 return origin_subst(xname, refobj->origin_path); 1132 else 1133 return xstrdup(xname); 1134 } 1135 1136 if (libmap_disable || (refobj == NULL) || 1137 (name = lm_find(refobj->path, xname)) == NULL) 1138 name = (char *)xname; 1139 1140 dbg(" Searching for \"%s\"", name); 1141 1142 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1143 (refobj != NULL && 1144 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1145 (pathname = search_library_path(name, gethints())) != NULL || 1146 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1147 return pathname; 1148 1149 if(refobj != NULL && refobj->path != NULL) { 1150 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1151 name, basename(refobj->path)); 1152 } else { 1153 _rtld_error("Shared object \"%s\" not found", name); 1154 } 1155 return NULL; 1156 } 1157 1158 /* 1159 * Given a symbol number in a referencing object, find the corresponding 1160 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1161 * no definition was found. Returns a pointer to the Obj_Entry of the 1162 * defining object via the reference parameter DEFOBJ_OUT. 1163 */ 1164 const Elf_Sym * 1165 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1166 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1167 { 1168 const Elf_Sym *ref; 1169 const Elf_Sym *def; 1170 const Obj_Entry *defobj; 1171 const Ver_Entry *ventry; 1172 const char *name; 1173 unsigned long hash; 1174 1175 /* 1176 * If we have already found this symbol, get the information from 1177 * the cache. 1178 */ 1179 if (symnum >= refobj->nchains) 1180 return NULL; /* Bad object */ 1181 if (cache != NULL && cache[symnum].sym != NULL) { 1182 *defobj_out = cache[symnum].obj; 1183 return cache[symnum].sym; 1184 } 1185 1186 ref = refobj->symtab + symnum; 1187 name = refobj->strtab + ref->st_name; 1188 defobj = NULL; 1189 1190 /* 1191 * We don't have to do a full scale lookup if the symbol is local. 1192 * We know it will bind to the instance in this load module; to 1193 * which we already have a pointer (ie ref). By not doing a lookup, 1194 * we not only improve performance, but it also avoids unresolvable 1195 * symbols when local symbols are not in the hash table. This has 1196 * been seen with the ia64 toolchain. 1197 */ 1198 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1199 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1200 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1201 symnum); 1202 } 1203 ventry = fetch_ventry(refobj, symnum); 1204 hash = elf_hash(name); 1205 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1206 } else { 1207 def = ref; 1208 defobj = refobj; 1209 } 1210 1211 /* 1212 * If we found no definition and the reference is weak, treat the 1213 * symbol as having the value zero. 1214 */ 1215 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1216 def = &sym_zero; 1217 defobj = obj_main; 1218 } 1219 1220 if (def != NULL) { 1221 *defobj_out = defobj; 1222 /* Record the information in the cache to avoid subsequent lookups. */ 1223 if (cache != NULL) { 1224 cache[symnum].sym = def; 1225 cache[symnum].obj = defobj; 1226 } 1227 } else { 1228 if (refobj != &obj_rtld) 1229 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1230 } 1231 return def; 1232 } 1233 1234 /* 1235 * Return the search path from the ldconfig hints file, reading it if 1236 * necessary. Returns NULL if there are problems with the hints file, 1237 * or if the search path there is empty. 1238 */ 1239 static const char * 1240 gethints(void) 1241 { 1242 static char *hints; 1243 1244 if (hints == NULL) { 1245 int fd; 1246 struct elfhints_hdr hdr; 1247 char *p; 1248 1249 /* Keep from trying again in case the hints file is bad. */ 1250 hints = ""; 1251 1252 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1253 return NULL; 1254 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1255 hdr.magic != ELFHINTS_MAGIC || 1256 hdr.version != 1) { 1257 close(fd); 1258 return NULL; 1259 } 1260 p = xmalloc(hdr.dirlistlen + 1); 1261 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1262 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1263 free(p); 1264 close(fd); 1265 return NULL; 1266 } 1267 hints = p; 1268 close(fd); 1269 } 1270 return hints[0] != '\0' ? hints : NULL; 1271 } 1272 1273 static void 1274 init_dag(Obj_Entry *root) 1275 { 1276 DoneList donelist; 1277 1278 donelist_init(&donelist); 1279 init_dag1(root, root, &donelist); 1280 } 1281 1282 static void 1283 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1284 { 1285 const Needed_Entry *needed; 1286 1287 if (donelist_check(dlp, obj)) 1288 return; 1289 1290 obj->refcount++; 1291 objlist_push_tail(&obj->dldags, root); 1292 objlist_push_tail(&root->dagmembers, obj); 1293 for (needed = obj->needed; needed != NULL; needed = needed->next) 1294 if (needed->obj != NULL) 1295 init_dag1(root, needed->obj, dlp); 1296 } 1297 1298 /* 1299 * Initialize the dynamic linker. The argument is the address at which 1300 * the dynamic linker has been mapped into memory. The primary task of 1301 * this function is to relocate the dynamic linker. 1302 */ 1303 static void 1304 init_rtld(caddr_t mapbase) 1305 { 1306 Obj_Entry objtmp; /* Temporary rtld object */ 1307 1308 /* 1309 * Conjure up an Obj_Entry structure for the dynamic linker. 1310 * 1311 * The "path" member can't be initialized yet because string constatns 1312 * cannot yet be acessed. Below we will set it correctly. 1313 */ 1314 memset(&objtmp, 0, sizeof(objtmp)); 1315 objtmp.path = NULL; 1316 objtmp.rtld = true; 1317 objtmp.mapbase = mapbase; 1318 #ifdef PIC 1319 objtmp.relocbase = mapbase; 1320 #endif 1321 if (RTLD_IS_DYNAMIC()) { 1322 objtmp.dynamic = rtld_dynamic(&objtmp); 1323 digest_dynamic(&objtmp, 1); 1324 assert(objtmp.needed == NULL); 1325 #if !defined(__mips__) 1326 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1327 assert(!objtmp.textrel); 1328 #endif 1329 1330 /* 1331 * Temporarily put the dynamic linker entry into the object list, so 1332 * that symbols can be found. 1333 */ 1334 1335 relocate_objects(&objtmp, true, &objtmp); 1336 } 1337 1338 /* Initialize the object list. */ 1339 obj_tail = &obj_list; 1340 1341 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1342 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1343 1344 /* Replace the path with a dynamically allocated copy. */ 1345 obj_rtld.path = xstrdup(PATH_RTLD); 1346 1347 r_debug.r_brk = r_debug_state; 1348 r_debug.r_state = RT_CONSISTENT; 1349 } 1350 1351 /* 1352 * Add the init functions from a needed object list (and its recursive 1353 * needed objects) to "list". This is not used directly; it is a helper 1354 * function for initlist_add_objects(). The write lock must be held 1355 * when this function is called. 1356 */ 1357 static void 1358 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1359 { 1360 /* Recursively process the successor needed objects. */ 1361 if (needed->next != NULL) 1362 initlist_add_neededs(needed->next, list); 1363 1364 /* Process the current needed object. */ 1365 if (needed->obj != NULL) 1366 initlist_add_objects(needed->obj, &needed->obj->next, list); 1367 } 1368 1369 /* 1370 * Scan all of the DAGs rooted in the range of objects from "obj" to 1371 * "tail" and add their init functions to "list". This recurses over 1372 * the DAGs and ensure the proper init ordering such that each object's 1373 * needed libraries are initialized before the object itself. At the 1374 * same time, this function adds the objects to the global finalization 1375 * list "list_fini" in the opposite order. The write lock must be 1376 * held when this function is called. 1377 */ 1378 static void 1379 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1380 { 1381 if (obj->init_scanned || obj->init_done) 1382 return; 1383 obj->init_scanned = true; 1384 1385 /* Recursively process the successor objects. */ 1386 if (&obj->next != tail) 1387 initlist_add_objects(obj->next, tail, list); 1388 1389 /* Recursively process the needed objects. */ 1390 if (obj->needed != NULL) 1391 initlist_add_neededs(obj->needed, list); 1392 1393 /* Add the object to the init list. */ 1394 if (obj->init != (Elf_Addr)NULL) 1395 objlist_push_tail(list, obj); 1396 1397 /* Add the object to the global fini list in the reverse order. */ 1398 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1399 objlist_push_head(&list_fini, obj); 1400 obj->on_fini_list = true; 1401 } 1402 } 1403 1404 #ifndef FPTR_TARGET 1405 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1406 #endif 1407 1408 static bool 1409 is_exported(const Elf_Sym *def) 1410 { 1411 Elf_Addr value; 1412 const func_ptr_type *p; 1413 1414 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1415 for (p = exports; *p != NULL; p++) 1416 if (FPTR_TARGET(*p) == value) 1417 return true; 1418 return false; 1419 } 1420 1421 /* 1422 * Given a shared object, traverse its list of needed objects, and load 1423 * each of them. Returns 0 on success. Generates an error message and 1424 * returns -1 on failure. 1425 */ 1426 static int 1427 load_needed_objects(Obj_Entry *first) 1428 { 1429 Obj_Entry *obj, *obj1; 1430 1431 for (obj = first; obj != NULL; obj = obj->next) { 1432 Needed_Entry *needed; 1433 1434 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1435 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj); 1436 if (obj1 == NULL && !ld_tracing) 1437 return -1; 1438 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1439 dbg("obj %s nodelete", obj1->path); 1440 init_dag(obj1); 1441 ref_dag(obj1); 1442 obj1->ref_nodel = true; 1443 } 1444 } 1445 } 1446 1447 return 0; 1448 } 1449 1450 static int 1451 load_preload_objects(void) 1452 { 1453 char *p = ld_preload; 1454 static const char delim[] = " \t:;"; 1455 1456 if (p == NULL) 1457 return 0; 1458 1459 p += strspn(p, delim); 1460 while (*p != '\0') { 1461 size_t len = strcspn(p, delim); 1462 char savech; 1463 1464 savech = p[len]; 1465 p[len] = '\0'; 1466 if (load_object(p, NULL) == NULL) 1467 return -1; /* XXX - cleanup */ 1468 p[len] = savech; 1469 p += len; 1470 p += strspn(p, delim); 1471 } 1472 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1473 return 0; 1474 } 1475 1476 /* 1477 * Load a shared object into memory, if it is not already loaded. 1478 * 1479 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1480 * on failure. 1481 */ 1482 static Obj_Entry * 1483 load_object(const char *name, const Obj_Entry *refobj) 1484 { 1485 Obj_Entry *obj; 1486 int fd = -1; 1487 struct stat sb; 1488 char *path; 1489 1490 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1491 if (object_match_name(obj, name)) 1492 return obj; 1493 1494 path = find_library(name, refobj); 1495 if (path == NULL) 1496 return NULL; 1497 1498 /* 1499 * If we didn't find a match by pathname, open the file and check 1500 * again by device and inode. This avoids false mismatches caused 1501 * by multiple links or ".." in pathnames. 1502 * 1503 * To avoid a race, we open the file and use fstat() rather than 1504 * using stat(). 1505 */ 1506 if ((fd = open(path, O_RDONLY)) == -1) { 1507 _rtld_error("Cannot open \"%s\"", path); 1508 free(path); 1509 return NULL; 1510 } 1511 if (fstat(fd, &sb) == -1) { 1512 _rtld_error("Cannot fstat \"%s\"", path); 1513 close(fd); 1514 free(path); 1515 return NULL; 1516 } 1517 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1518 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1519 close(fd); 1520 break; 1521 } 1522 } 1523 if (obj != NULL) { 1524 object_add_name(obj, name); 1525 free(path); 1526 close(fd); 1527 return obj; 1528 } 1529 1530 /* First use of this object, so we must map it in */ 1531 obj = do_load_object(fd, name, path, &sb); 1532 if (obj == NULL) 1533 free(path); 1534 close(fd); 1535 1536 return obj; 1537 } 1538 1539 static Obj_Entry * 1540 do_load_object(int fd, const char *name, char *path, struct stat *sbp) 1541 { 1542 Obj_Entry *obj; 1543 struct statfs fs; 1544 1545 /* 1546 * but first, make sure that environment variables haven't been 1547 * used to circumvent the noexec flag on a filesystem. 1548 */ 1549 if (dangerous_ld_env) { 1550 if (fstatfs(fd, &fs) != 0) { 1551 _rtld_error("Cannot fstatfs \"%s\"", path); 1552 return NULL; 1553 } 1554 if (fs.f_flags & MNT_NOEXEC) { 1555 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1556 return NULL; 1557 } 1558 } 1559 dbg("loading \"%s\"", path); 1560 obj = map_object(fd, path, sbp); 1561 if (obj == NULL) 1562 return NULL; 1563 1564 object_add_name(obj, name); 1565 obj->path = path; 1566 digest_dynamic(obj, 0); 1567 1568 *obj_tail = obj; 1569 obj_tail = &obj->next; 1570 obj_count++; 1571 obj_loads++; 1572 linkmap_add(obj); /* for GDB & dlinfo() */ 1573 1574 dbg(" %p .. %p: %s", obj->mapbase, 1575 obj->mapbase + obj->mapsize - 1, obj->path); 1576 if (obj->textrel) 1577 dbg(" WARNING: %s has impure text", obj->path); 1578 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1579 obj->path); 1580 1581 return obj; 1582 } 1583 1584 static Obj_Entry * 1585 obj_from_addr(const void *addr) 1586 { 1587 Obj_Entry *obj; 1588 1589 for (obj = obj_list; obj != NULL; obj = obj->next) { 1590 if (addr < (void *) obj->mapbase) 1591 continue; 1592 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1593 return obj; 1594 } 1595 return NULL; 1596 } 1597 1598 /* 1599 * Call the finalization functions for each of the objects in "list" 1600 * which are unreferenced. All of the objects are expected to have 1601 * non-NULL fini functions. 1602 */ 1603 static void 1604 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1605 { 1606 Objlist_Entry *elm, *elm_tmp; 1607 char *saved_msg; 1608 1609 /* 1610 * Preserve the current error message since a fini function might 1611 * call into the dynamic linker and overwrite it. 1612 */ 1613 saved_msg = errmsg_save(); 1614 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1615 if (elm->obj->refcount == 0 || force) { 1616 dbg("calling fini function for %s at %p", elm->obj->path, 1617 (void *)elm->obj->fini); 1618 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1619 elm->obj->path); 1620 /* Remove object from fini list to prevent recursive invocation. */ 1621 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1622 wlock_release(rtld_bind_lock, *lockstate); 1623 call_initfini_pointer(elm->obj, elm->obj->fini); 1624 *lockstate = wlock_acquire(rtld_bind_lock); 1625 /* No need to free anything if process is going down. */ 1626 if (!force) 1627 free(elm); 1628 } 1629 } 1630 errmsg_restore(saved_msg); 1631 } 1632 1633 /* 1634 * Call the initialization functions for each of the objects in 1635 * "list". All of the objects are expected to have non-NULL init 1636 * functions. 1637 */ 1638 static void 1639 objlist_call_init(Objlist *list, int *lockstate) 1640 { 1641 Objlist_Entry *elm; 1642 Obj_Entry *obj; 1643 char *saved_msg; 1644 1645 /* 1646 * Clean init_scanned flag so that objects can be rechecked and 1647 * possibly initialized earlier if any of vectors called below 1648 * cause the change by using dlopen. 1649 */ 1650 for (obj = obj_list; obj != NULL; obj = obj->next) 1651 obj->init_scanned = false; 1652 1653 /* 1654 * Preserve the current error message since an init function might 1655 * call into the dynamic linker and overwrite it. 1656 */ 1657 saved_msg = errmsg_save(); 1658 STAILQ_FOREACH(elm, list, link) { 1659 if (elm->obj->init_done) /* Initialized early. */ 1660 continue; 1661 dbg("calling init function for %s at %p", elm->obj->path, 1662 (void *)elm->obj->init); 1663 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1664 elm->obj->path); 1665 /* 1666 * Race: other thread might try to use this object before current 1667 * one completes the initilization. Not much can be done here 1668 * without better locking. 1669 */ 1670 elm->obj->init_done = true; 1671 wlock_release(rtld_bind_lock, *lockstate); 1672 call_initfini_pointer(elm->obj, elm->obj->init); 1673 *lockstate = wlock_acquire(rtld_bind_lock); 1674 } 1675 errmsg_restore(saved_msg); 1676 } 1677 1678 static void 1679 objlist_clear(Objlist *list) 1680 { 1681 Objlist_Entry *elm; 1682 1683 while (!STAILQ_EMPTY(list)) { 1684 elm = STAILQ_FIRST(list); 1685 STAILQ_REMOVE_HEAD(list, link); 1686 free(elm); 1687 } 1688 } 1689 1690 static Objlist_Entry * 1691 objlist_find(Objlist *list, const Obj_Entry *obj) 1692 { 1693 Objlist_Entry *elm; 1694 1695 STAILQ_FOREACH(elm, list, link) 1696 if (elm->obj == obj) 1697 return elm; 1698 return NULL; 1699 } 1700 1701 static void 1702 objlist_init(Objlist *list) 1703 { 1704 STAILQ_INIT(list); 1705 } 1706 1707 static void 1708 objlist_push_head(Objlist *list, Obj_Entry *obj) 1709 { 1710 Objlist_Entry *elm; 1711 1712 elm = NEW(Objlist_Entry); 1713 elm->obj = obj; 1714 STAILQ_INSERT_HEAD(list, elm, link); 1715 } 1716 1717 static void 1718 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1719 { 1720 Objlist_Entry *elm; 1721 1722 elm = NEW(Objlist_Entry); 1723 elm->obj = obj; 1724 STAILQ_INSERT_TAIL(list, elm, link); 1725 } 1726 1727 static void 1728 objlist_remove(Objlist *list, Obj_Entry *obj) 1729 { 1730 Objlist_Entry *elm; 1731 1732 if ((elm = objlist_find(list, obj)) != NULL) { 1733 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1734 free(elm); 1735 } 1736 } 1737 1738 /* 1739 * Relocate newly-loaded shared objects. The argument is a pointer to 1740 * the Obj_Entry for the first such object. All objects from the first 1741 * to the end of the list of objects are relocated. Returns 0 on success, 1742 * or -1 on failure. 1743 */ 1744 static int 1745 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1746 { 1747 Obj_Entry *obj; 1748 1749 for (obj = first; obj != NULL; obj = obj->next) { 1750 if (obj != rtldobj) 1751 dbg("relocating \"%s\"", obj->path); 1752 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1753 obj->symtab == NULL || obj->strtab == NULL) { 1754 _rtld_error("%s: Shared object has no run-time symbol table", 1755 obj->path); 1756 return -1; 1757 } 1758 1759 if (obj->textrel) { 1760 /* There are relocations to the write-protected text segment. */ 1761 if (mprotect(obj->mapbase, obj->textsize, 1762 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1763 _rtld_error("%s: Cannot write-enable text segment: %s", 1764 obj->path, strerror(errno)); 1765 return -1; 1766 } 1767 } 1768 1769 /* Process the non-PLT relocations. */ 1770 if (reloc_non_plt(obj, rtldobj)) 1771 return -1; 1772 1773 if (obj->textrel) { /* Re-protected the text segment. */ 1774 if (mprotect(obj->mapbase, obj->textsize, 1775 PROT_READ|PROT_EXEC) == -1) { 1776 _rtld_error("%s: Cannot write-protect text segment: %s", 1777 obj->path, strerror(errno)); 1778 return -1; 1779 } 1780 } 1781 1782 /* Process the PLT relocations. */ 1783 if (reloc_plt(obj) == -1) 1784 return -1; 1785 /* Relocate the jump slots if we are doing immediate binding. */ 1786 if (obj->bind_now || bind_now) 1787 if (reloc_jmpslots(obj) == -1) 1788 return -1; 1789 1790 1791 /* 1792 * Set up the magic number and version in the Obj_Entry. These 1793 * were checked in the crt1.o from the original ElfKit, so we 1794 * set them for backward compatibility. 1795 */ 1796 obj->magic = RTLD_MAGIC; 1797 obj->version = RTLD_VERSION; 1798 1799 /* Set the special PLT or GOT entries. */ 1800 init_pltgot(obj); 1801 } 1802 1803 return 0; 1804 } 1805 1806 /* 1807 * Cleanup procedure. It will be called (by the atexit mechanism) just 1808 * before the process exits. 1809 */ 1810 static void 1811 rtld_exit(void) 1812 { 1813 int lockstate; 1814 1815 lockstate = wlock_acquire(rtld_bind_lock); 1816 dbg("rtld_exit()"); 1817 objlist_call_fini(&list_fini, true, &lockstate); 1818 /* No need to remove the items from the list, since we are exiting. */ 1819 if (!libmap_disable) 1820 lm_fini(); 1821 wlock_release(rtld_bind_lock, lockstate); 1822 } 1823 1824 static void * 1825 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1826 { 1827 #ifdef COMPAT_32BIT 1828 const char *trans; 1829 #endif 1830 if (path == NULL) 1831 return (NULL); 1832 1833 path += strspn(path, ":;"); 1834 while (*path != '\0') { 1835 size_t len; 1836 char *res; 1837 1838 len = strcspn(path, ":;"); 1839 #ifdef COMPAT_32BIT 1840 trans = lm_findn(NULL, path, len); 1841 if (trans) 1842 res = callback(trans, strlen(trans), arg); 1843 else 1844 #endif 1845 res = callback(path, len, arg); 1846 1847 if (res != NULL) 1848 return (res); 1849 1850 path += len; 1851 path += strspn(path, ":;"); 1852 } 1853 1854 return (NULL); 1855 } 1856 1857 struct try_library_args { 1858 const char *name; 1859 size_t namelen; 1860 char *buffer; 1861 size_t buflen; 1862 }; 1863 1864 static void * 1865 try_library_path(const char *dir, size_t dirlen, void *param) 1866 { 1867 struct try_library_args *arg; 1868 1869 arg = param; 1870 if (*dir == '/' || trust) { 1871 char *pathname; 1872 1873 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1874 return (NULL); 1875 1876 pathname = arg->buffer; 1877 strncpy(pathname, dir, dirlen); 1878 pathname[dirlen] = '/'; 1879 strcpy(pathname + dirlen + 1, arg->name); 1880 1881 dbg(" Trying \"%s\"", pathname); 1882 if (access(pathname, F_OK) == 0) { /* We found it */ 1883 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1884 strcpy(pathname, arg->buffer); 1885 return (pathname); 1886 } 1887 } 1888 return (NULL); 1889 } 1890 1891 static char * 1892 search_library_path(const char *name, const char *path) 1893 { 1894 char *p; 1895 struct try_library_args arg; 1896 1897 if (path == NULL) 1898 return NULL; 1899 1900 arg.name = name; 1901 arg.namelen = strlen(name); 1902 arg.buffer = xmalloc(PATH_MAX); 1903 arg.buflen = PATH_MAX; 1904 1905 p = path_enumerate(path, try_library_path, &arg); 1906 1907 free(arg.buffer); 1908 1909 return (p); 1910 } 1911 1912 int 1913 dlclose(void *handle) 1914 { 1915 Obj_Entry *root; 1916 int lockstate; 1917 1918 lockstate = wlock_acquire(rtld_bind_lock); 1919 root = dlcheck(handle); 1920 if (root == NULL) { 1921 wlock_release(rtld_bind_lock, lockstate); 1922 return -1; 1923 } 1924 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1925 root->path); 1926 1927 /* Unreference the object and its dependencies. */ 1928 root->dl_refcount--; 1929 1930 unref_dag(root); 1931 1932 if (root->refcount == 0) { 1933 /* 1934 * The object is no longer referenced, so we must unload it. 1935 * First, call the fini functions. 1936 */ 1937 objlist_call_fini(&list_fini, false, &lockstate); 1938 1939 /* Finish cleaning up the newly-unreferenced objects. */ 1940 GDB_STATE(RT_DELETE,&root->linkmap); 1941 unload_object(root); 1942 GDB_STATE(RT_CONSISTENT,NULL); 1943 } 1944 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1945 wlock_release(rtld_bind_lock, lockstate); 1946 return 0; 1947 } 1948 1949 const char * 1950 dlerror(void) 1951 { 1952 char *msg = error_message; 1953 error_message = NULL; 1954 return msg; 1955 } 1956 1957 /* 1958 * This function is deprecated and has no effect. 1959 */ 1960 void 1961 dllockinit(void *context, 1962 void *(*lock_create)(void *context), 1963 void (*rlock_acquire)(void *lock), 1964 void (*wlock_acquire)(void *lock), 1965 void (*lock_release)(void *lock), 1966 void (*lock_destroy)(void *lock), 1967 void (*context_destroy)(void *context)) 1968 { 1969 static void *cur_context; 1970 static void (*cur_context_destroy)(void *); 1971 1972 /* Just destroy the context from the previous call, if necessary. */ 1973 if (cur_context_destroy != NULL) 1974 cur_context_destroy(cur_context); 1975 cur_context = context; 1976 cur_context_destroy = context_destroy; 1977 } 1978 1979 void * 1980 dlopen(const char *name, int mode) 1981 { 1982 Obj_Entry **old_obj_tail; 1983 Obj_Entry *obj; 1984 Objlist initlist; 1985 int result, lockstate, nodelete; 1986 1987 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 1988 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1989 if (ld_tracing != NULL) 1990 environ = (char **)*get_program_var_addr("environ"); 1991 nodelete = mode & RTLD_NODELETE; 1992 1993 objlist_init(&initlist); 1994 1995 lockstate = wlock_acquire(rtld_bind_lock); 1996 GDB_STATE(RT_ADD,NULL); 1997 1998 old_obj_tail = obj_tail; 1999 obj = NULL; 2000 if (name == NULL) { 2001 obj = obj_main; 2002 obj->refcount++; 2003 } else { 2004 obj = load_object(name, obj_main); 2005 } 2006 2007 if (obj) { 2008 obj->dl_refcount++; 2009 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2010 objlist_push_tail(&list_global, obj); 2011 mode &= RTLD_MODEMASK; 2012 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2013 assert(*old_obj_tail == obj); 2014 result = load_needed_objects(obj); 2015 init_dag(obj); 2016 if (result != -1) 2017 result = rtld_verify_versions(&obj->dagmembers); 2018 if (result != -1 && ld_tracing) 2019 goto trace; 2020 if (result == -1 || 2021 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2022 obj->dl_refcount--; 2023 unref_dag(obj); 2024 if (obj->refcount == 0) 2025 unload_object(obj); 2026 obj = NULL; 2027 } else { 2028 /* Make list of init functions to call. */ 2029 initlist_add_objects(obj, &obj->next, &initlist); 2030 } 2031 } else { 2032 2033 /* Bump the reference counts for objects on this DAG. */ 2034 ref_dag(obj); 2035 2036 if (ld_tracing) 2037 goto trace; 2038 } 2039 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2040 dbg("obj %s nodelete", obj->path); 2041 ref_dag(obj); 2042 obj->z_nodelete = obj->ref_nodel = true; 2043 } 2044 } 2045 2046 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2047 name); 2048 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2049 2050 /* Call the init functions. */ 2051 objlist_call_init(&initlist, &lockstate); 2052 objlist_clear(&initlist); 2053 wlock_release(rtld_bind_lock, lockstate); 2054 return obj; 2055 trace: 2056 trace_loaded_objects(obj); 2057 wlock_release(rtld_bind_lock, lockstate); 2058 exit(0); 2059 } 2060 2061 static void * 2062 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2063 int flags) 2064 { 2065 DoneList donelist; 2066 const Obj_Entry *obj, *defobj; 2067 const Elf_Sym *def, *symp; 2068 unsigned long hash; 2069 int lockstate; 2070 2071 hash = elf_hash(name); 2072 def = NULL; 2073 defobj = NULL; 2074 flags |= SYMLOOK_IN_PLT; 2075 2076 lockstate = rlock_acquire(rtld_bind_lock); 2077 if (handle == NULL || handle == RTLD_NEXT || 2078 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2079 2080 if ((obj = obj_from_addr(retaddr)) == NULL) { 2081 _rtld_error("Cannot determine caller's shared object"); 2082 rlock_release(rtld_bind_lock, lockstate); 2083 return NULL; 2084 } 2085 if (handle == NULL) { /* Just the caller's shared object. */ 2086 def = symlook_obj(name, hash, obj, ve, flags); 2087 defobj = obj; 2088 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2089 handle == RTLD_SELF) { /* ... caller included */ 2090 if (handle == RTLD_NEXT) 2091 obj = obj->next; 2092 for (; obj != NULL; obj = obj->next) { 2093 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2094 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2095 def = symp; 2096 defobj = obj; 2097 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2098 break; 2099 } 2100 } 2101 } 2102 /* 2103 * Search the dynamic linker itself, and possibly resolve the 2104 * symbol from there. This is how the application links to 2105 * dynamic linker services such as dlopen. Only the values listed 2106 * in the "exports" array can be resolved from the dynamic linker. 2107 */ 2108 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2109 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2110 if (symp != NULL && is_exported(symp)) { 2111 def = symp; 2112 defobj = &obj_rtld; 2113 } 2114 } 2115 } else { 2116 assert(handle == RTLD_DEFAULT); 2117 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2118 } 2119 } else { 2120 if ((obj = dlcheck(handle)) == NULL) { 2121 rlock_release(rtld_bind_lock, lockstate); 2122 return NULL; 2123 } 2124 2125 donelist_init(&donelist); 2126 if (obj->mainprog) { 2127 /* Search main program and all libraries loaded by it. */ 2128 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2129 &donelist); 2130 2131 /* 2132 * We do not distinguish between 'main' object and global scope. 2133 * If symbol is not defined by objects loaded at startup, continue 2134 * search among dynamically loaded objects with RTLD_GLOBAL 2135 * scope. 2136 */ 2137 if (def == NULL) 2138 def = symlook_list(name, hash, &list_global, &defobj, ve, 2139 flags, &donelist); 2140 } else { 2141 Needed_Entry fake; 2142 2143 /* Search the whole DAG rooted at the given object. */ 2144 fake.next = NULL; 2145 fake.obj = (Obj_Entry *)obj; 2146 fake.name = 0; 2147 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2148 &donelist); 2149 } 2150 } 2151 2152 if (def != NULL) { 2153 rlock_release(rtld_bind_lock, lockstate); 2154 2155 /* 2156 * The value required by the caller is derived from the value 2157 * of the symbol. For the ia64 architecture, we need to 2158 * construct a function descriptor which the caller can use to 2159 * call the function with the right 'gp' value. For other 2160 * architectures and for non-functions, the value is simply 2161 * the relocated value of the symbol. 2162 */ 2163 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2164 return make_function_pointer(def, defobj); 2165 else 2166 return defobj->relocbase + def->st_value; 2167 } 2168 2169 _rtld_error("Undefined symbol \"%s\"", name); 2170 rlock_release(rtld_bind_lock, lockstate); 2171 return NULL; 2172 } 2173 2174 void * 2175 dlsym(void *handle, const char *name) 2176 { 2177 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2178 SYMLOOK_DLSYM); 2179 } 2180 2181 dlfunc_t 2182 dlfunc(void *handle, const char *name) 2183 { 2184 union { 2185 void *d; 2186 dlfunc_t f; 2187 } rv; 2188 2189 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2190 SYMLOOK_DLSYM); 2191 return (rv.f); 2192 } 2193 2194 void * 2195 dlvsym(void *handle, const char *name, const char *version) 2196 { 2197 Ver_Entry ventry; 2198 2199 ventry.name = version; 2200 ventry.file = NULL; 2201 ventry.hash = elf_hash(version); 2202 ventry.flags= 0; 2203 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2204 SYMLOOK_DLSYM); 2205 } 2206 2207 int 2208 dladdr(const void *addr, Dl_info *info) 2209 { 2210 const Obj_Entry *obj; 2211 const Elf_Sym *def; 2212 void *symbol_addr; 2213 unsigned long symoffset; 2214 int lockstate; 2215 2216 lockstate = rlock_acquire(rtld_bind_lock); 2217 obj = obj_from_addr(addr); 2218 if (obj == NULL) { 2219 _rtld_error("No shared object contains address"); 2220 rlock_release(rtld_bind_lock, lockstate); 2221 return 0; 2222 } 2223 info->dli_fname = obj->path; 2224 info->dli_fbase = obj->mapbase; 2225 info->dli_saddr = (void *)0; 2226 info->dli_sname = NULL; 2227 2228 /* 2229 * Walk the symbol list looking for the symbol whose address is 2230 * closest to the address sent in. 2231 */ 2232 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2233 def = obj->symtab + symoffset; 2234 2235 /* 2236 * For skip the symbol if st_shndx is either SHN_UNDEF or 2237 * SHN_COMMON. 2238 */ 2239 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2240 continue; 2241 2242 /* 2243 * If the symbol is greater than the specified address, or if it 2244 * is further away from addr than the current nearest symbol, 2245 * then reject it. 2246 */ 2247 symbol_addr = obj->relocbase + def->st_value; 2248 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2249 continue; 2250 2251 /* Update our idea of the nearest symbol. */ 2252 info->dli_sname = obj->strtab + def->st_name; 2253 info->dli_saddr = symbol_addr; 2254 2255 /* Exact match? */ 2256 if (info->dli_saddr == addr) 2257 break; 2258 } 2259 rlock_release(rtld_bind_lock, lockstate); 2260 return 1; 2261 } 2262 2263 int 2264 dlinfo(void *handle, int request, void *p) 2265 { 2266 const Obj_Entry *obj; 2267 int error, lockstate; 2268 2269 lockstate = rlock_acquire(rtld_bind_lock); 2270 2271 if (handle == NULL || handle == RTLD_SELF) { 2272 void *retaddr; 2273 2274 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2275 if ((obj = obj_from_addr(retaddr)) == NULL) 2276 _rtld_error("Cannot determine caller's shared object"); 2277 } else 2278 obj = dlcheck(handle); 2279 2280 if (obj == NULL) { 2281 rlock_release(rtld_bind_lock, lockstate); 2282 return (-1); 2283 } 2284 2285 error = 0; 2286 switch (request) { 2287 case RTLD_DI_LINKMAP: 2288 *((struct link_map const **)p) = &obj->linkmap; 2289 break; 2290 case RTLD_DI_ORIGIN: 2291 error = rtld_dirname(obj->path, p); 2292 break; 2293 2294 case RTLD_DI_SERINFOSIZE: 2295 case RTLD_DI_SERINFO: 2296 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2297 break; 2298 2299 default: 2300 _rtld_error("Invalid request %d passed to dlinfo()", request); 2301 error = -1; 2302 } 2303 2304 rlock_release(rtld_bind_lock, lockstate); 2305 2306 return (error); 2307 } 2308 2309 int 2310 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2311 { 2312 struct dl_phdr_info phdr_info; 2313 const Obj_Entry *obj; 2314 int error, bind_lockstate, phdr_lockstate; 2315 2316 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2317 bind_lockstate = rlock_acquire(rtld_bind_lock); 2318 2319 error = 0; 2320 2321 for (obj = obj_list; obj != NULL; obj = obj->next) { 2322 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2323 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2324 STAILQ_FIRST(&obj->names)->name : obj->path; 2325 phdr_info.dlpi_phdr = obj->phdr; 2326 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2327 phdr_info.dlpi_tls_modid = obj->tlsindex; 2328 phdr_info.dlpi_tls_data = obj->tlsinit; 2329 phdr_info.dlpi_adds = obj_loads; 2330 phdr_info.dlpi_subs = obj_loads - obj_count; 2331 2332 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2333 break; 2334 2335 } 2336 rlock_release(rtld_bind_lock, bind_lockstate); 2337 wlock_release(rtld_phdr_lock, phdr_lockstate); 2338 2339 return (error); 2340 } 2341 2342 struct fill_search_info_args { 2343 int request; 2344 unsigned int flags; 2345 Dl_serinfo *serinfo; 2346 Dl_serpath *serpath; 2347 char *strspace; 2348 }; 2349 2350 static void * 2351 fill_search_info(const char *dir, size_t dirlen, void *param) 2352 { 2353 struct fill_search_info_args *arg; 2354 2355 arg = param; 2356 2357 if (arg->request == RTLD_DI_SERINFOSIZE) { 2358 arg->serinfo->dls_cnt ++; 2359 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2360 } else { 2361 struct dl_serpath *s_entry; 2362 2363 s_entry = arg->serpath; 2364 s_entry->dls_name = arg->strspace; 2365 s_entry->dls_flags = arg->flags; 2366 2367 strncpy(arg->strspace, dir, dirlen); 2368 arg->strspace[dirlen] = '\0'; 2369 2370 arg->strspace += dirlen + 1; 2371 arg->serpath++; 2372 } 2373 2374 return (NULL); 2375 } 2376 2377 static int 2378 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2379 { 2380 struct dl_serinfo _info; 2381 struct fill_search_info_args args; 2382 2383 args.request = RTLD_DI_SERINFOSIZE; 2384 args.serinfo = &_info; 2385 2386 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2387 _info.dls_cnt = 0; 2388 2389 path_enumerate(ld_library_path, fill_search_info, &args); 2390 path_enumerate(obj->rpath, fill_search_info, &args); 2391 path_enumerate(gethints(), fill_search_info, &args); 2392 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2393 2394 2395 if (request == RTLD_DI_SERINFOSIZE) { 2396 info->dls_size = _info.dls_size; 2397 info->dls_cnt = _info.dls_cnt; 2398 return (0); 2399 } 2400 2401 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2402 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2403 return (-1); 2404 } 2405 2406 args.request = RTLD_DI_SERINFO; 2407 args.serinfo = info; 2408 args.serpath = &info->dls_serpath[0]; 2409 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2410 2411 args.flags = LA_SER_LIBPATH; 2412 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2413 return (-1); 2414 2415 args.flags = LA_SER_RUNPATH; 2416 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2417 return (-1); 2418 2419 args.flags = LA_SER_CONFIG; 2420 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2421 return (-1); 2422 2423 args.flags = LA_SER_DEFAULT; 2424 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2425 return (-1); 2426 return (0); 2427 } 2428 2429 static int 2430 rtld_dirname(const char *path, char *bname) 2431 { 2432 const char *endp; 2433 2434 /* Empty or NULL string gets treated as "." */ 2435 if (path == NULL || *path == '\0') { 2436 bname[0] = '.'; 2437 bname[1] = '\0'; 2438 return (0); 2439 } 2440 2441 /* Strip trailing slashes */ 2442 endp = path + strlen(path) - 1; 2443 while (endp > path && *endp == '/') 2444 endp--; 2445 2446 /* Find the start of the dir */ 2447 while (endp > path && *endp != '/') 2448 endp--; 2449 2450 /* Either the dir is "/" or there are no slashes */ 2451 if (endp == path) { 2452 bname[0] = *endp == '/' ? '/' : '.'; 2453 bname[1] = '\0'; 2454 return (0); 2455 } else { 2456 do { 2457 endp--; 2458 } while (endp > path && *endp == '/'); 2459 } 2460 2461 if (endp - path + 2 > PATH_MAX) 2462 { 2463 _rtld_error("Filename is too long: %s", path); 2464 return(-1); 2465 } 2466 2467 strncpy(bname, path, endp - path + 1); 2468 bname[endp - path + 1] = '\0'; 2469 return (0); 2470 } 2471 2472 static int 2473 rtld_dirname_abs(const char *path, char *base) 2474 { 2475 char base_rel[PATH_MAX]; 2476 2477 if (rtld_dirname(path, base) == -1) 2478 return (-1); 2479 if (base[0] == '/') 2480 return (0); 2481 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2482 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2483 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2484 return (-1); 2485 strcpy(base, base_rel); 2486 return (0); 2487 } 2488 2489 static void 2490 linkmap_add(Obj_Entry *obj) 2491 { 2492 struct link_map *l = &obj->linkmap; 2493 struct link_map *prev; 2494 2495 obj->linkmap.l_name = obj->path; 2496 obj->linkmap.l_addr = obj->mapbase; 2497 obj->linkmap.l_ld = obj->dynamic; 2498 #ifdef __mips__ 2499 /* GDB needs load offset on MIPS to use the symbols */ 2500 obj->linkmap.l_offs = obj->relocbase; 2501 #endif 2502 2503 if (r_debug.r_map == NULL) { 2504 r_debug.r_map = l; 2505 return; 2506 } 2507 2508 /* 2509 * Scan to the end of the list, but not past the entry for the 2510 * dynamic linker, which we want to keep at the very end. 2511 */ 2512 for (prev = r_debug.r_map; 2513 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2514 prev = prev->l_next) 2515 ; 2516 2517 /* Link in the new entry. */ 2518 l->l_prev = prev; 2519 l->l_next = prev->l_next; 2520 if (l->l_next != NULL) 2521 l->l_next->l_prev = l; 2522 prev->l_next = l; 2523 } 2524 2525 static void 2526 linkmap_delete(Obj_Entry *obj) 2527 { 2528 struct link_map *l = &obj->linkmap; 2529 2530 if (l->l_prev == NULL) { 2531 if ((r_debug.r_map = l->l_next) != NULL) 2532 l->l_next->l_prev = NULL; 2533 return; 2534 } 2535 2536 if ((l->l_prev->l_next = l->l_next) != NULL) 2537 l->l_next->l_prev = l->l_prev; 2538 } 2539 2540 /* 2541 * Function for the debugger to set a breakpoint on to gain control. 2542 * 2543 * The two parameters allow the debugger to easily find and determine 2544 * what the runtime loader is doing and to whom it is doing it. 2545 * 2546 * When the loadhook trap is hit (r_debug_state, set at program 2547 * initialization), the arguments can be found on the stack: 2548 * 2549 * +8 struct link_map *m 2550 * +4 struct r_debug *rd 2551 * +0 RetAddr 2552 */ 2553 void 2554 r_debug_state(struct r_debug* rd, struct link_map *m) 2555 { 2556 } 2557 2558 /* 2559 * Get address of the pointer variable in the main program. 2560 */ 2561 static const void ** 2562 get_program_var_addr(const char *name) 2563 { 2564 const Obj_Entry *obj; 2565 unsigned long hash; 2566 2567 hash = elf_hash(name); 2568 for (obj = obj_main; obj != NULL; obj = obj->next) { 2569 const Elf_Sym *def; 2570 2571 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2572 const void **addr; 2573 2574 addr = (const void **)(obj->relocbase + def->st_value); 2575 return addr; 2576 } 2577 } 2578 return NULL; 2579 } 2580 2581 /* 2582 * Set a pointer variable in the main program to the given value. This 2583 * is used to set key variables such as "environ" before any of the 2584 * init functions are called. 2585 */ 2586 static void 2587 set_program_var(const char *name, const void *value) 2588 { 2589 const void **addr; 2590 2591 if ((addr = get_program_var_addr(name)) != NULL) { 2592 dbg("\"%s\": *%p <-- %p", name, addr, value); 2593 *addr = value; 2594 } 2595 } 2596 2597 /* 2598 * Given a symbol name in a referencing object, find the corresponding 2599 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2600 * no definition was found. Returns a pointer to the Obj_Entry of the 2601 * defining object via the reference parameter DEFOBJ_OUT. 2602 */ 2603 static const Elf_Sym * 2604 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2605 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2606 { 2607 DoneList donelist; 2608 const Elf_Sym *def; 2609 const Elf_Sym *symp; 2610 const Obj_Entry *obj; 2611 const Obj_Entry *defobj; 2612 const Objlist_Entry *elm; 2613 def = NULL; 2614 defobj = NULL; 2615 donelist_init(&donelist); 2616 2617 /* Look first in the referencing object if linked symbolically. */ 2618 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2619 symp = symlook_obj(name, hash, refobj, ventry, flags); 2620 if (symp != NULL) { 2621 def = symp; 2622 defobj = refobj; 2623 } 2624 } 2625 2626 /* Search all objects loaded at program start up. */ 2627 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2628 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2629 &donelist); 2630 if (symp != NULL && 2631 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2632 def = symp; 2633 defobj = obj; 2634 } 2635 } 2636 2637 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2638 STAILQ_FOREACH(elm, &list_global, link) { 2639 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2640 break; 2641 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2642 flags, &donelist); 2643 if (symp != NULL && 2644 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2645 def = symp; 2646 defobj = obj; 2647 } 2648 } 2649 2650 /* Search all dlopened DAGs containing the referencing object. */ 2651 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2652 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2653 break; 2654 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2655 flags, &donelist); 2656 if (symp != NULL && 2657 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2658 def = symp; 2659 defobj = obj; 2660 } 2661 } 2662 2663 /* 2664 * Search the dynamic linker itself, and possibly resolve the 2665 * symbol from there. This is how the application links to 2666 * dynamic linker services such as dlopen. Only the values listed 2667 * in the "exports" array can be resolved from the dynamic linker. 2668 */ 2669 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2670 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2671 if (symp != NULL && is_exported(symp)) { 2672 def = symp; 2673 defobj = &obj_rtld; 2674 } 2675 } 2676 2677 if (def != NULL) 2678 *defobj_out = defobj; 2679 return def; 2680 } 2681 2682 static const Elf_Sym * 2683 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2684 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2685 DoneList *dlp) 2686 { 2687 const Elf_Sym *symp; 2688 const Elf_Sym *def; 2689 const Obj_Entry *defobj; 2690 const Objlist_Entry *elm; 2691 2692 def = NULL; 2693 defobj = NULL; 2694 STAILQ_FOREACH(elm, objlist, link) { 2695 if (donelist_check(dlp, elm->obj)) 2696 continue; 2697 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2698 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2699 def = symp; 2700 defobj = elm->obj; 2701 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2702 break; 2703 } 2704 } 2705 } 2706 if (def != NULL) 2707 *defobj_out = defobj; 2708 return def; 2709 } 2710 2711 /* 2712 * Search the symbol table of a shared object and all objects needed 2713 * by it for a symbol of the given name. Search order is 2714 * breadth-first. Returns a pointer to the symbol, or NULL if no 2715 * definition was found. 2716 */ 2717 static const Elf_Sym * 2718 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2719 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2720 DoneList *dlp) 2721 { 2722 const Elf_Sym *def, *def_w; 2723 const Needed_Entry *n; 2724 const Obj_Entry *obj, *defobj, *defobj1; 2725 2726 def = def_w = NULL; 2727 defobj = NULL; 2728 for (n = needed; n != NULL; n = n->next) { 2729 if ((obj = n->obj) == NULL || 2730 donelist_check(dlp, obj) || 2731 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2732 continue; 2733 defobj = obj; 2734 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2735 *defobj_out = defobj; 2736 return (def); 2737 } 2738 } 2739 /* 2740 * There we come when either symbol definition is not found in 2741 * directly needed objects, or found symbol is weak. 2742 */ 2743 for (n = needed; n != NULL; n = n->next) { 2744 if ((obj = n->obj) == NULL) 2745 continue; 2746 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2747 ventry, flags, dlp); 2748 if (def_w == NULL) 2749 continue; 2750 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2751 def = def_w; 2752 defobj = defobj1; 2753 } 2754 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2755 break; 2756 } 2757 if (def != NULL) 2758 *defobj_out = defobj; 2759 return (def); 2760 } 2761 2762 /* 2763 * Search the symbol table of a single shared object for a symbol of 2764 * the given name and version, if requested. Returns a pointer to the 2765 * symbol, or NULL if no definition was found. 2766 * 2767 * The symbol's hash value is passed in for efficiency reasons; that 2768 * eliminates many recomputations of the hash value. 2769 */ 2770 const Elf_Sym * 2771 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2772 const Ver_Entry *ventry, int flags) 2773 { 2774 unsigned long symnum; 2775 const Elf_Sym *vsymp; 2776 Elf_Versym verndx; 2777 int vcount; 2778 2779 if (obj->buckets == NULL) 2780 return NULL; 2781 2782 vsymp = NULL; 2783 vcount = 0; 2784 symnum = obj->buckets[hash % obj->nbuckets]; 2785 2786 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2787 const Elf_Sym *symp; 2788 const char *strp; 2789 2790 if (symnum >= obj->nchains) 2791 return NULL; /* Bad object */ 2792 2793 symp = obj->symtab + symnum; 2794 strp = obj->strtab + symp->st_name; 2795 2796 switch (ELF_ST_TYPE(symp->st_info)) { 2797 case STT_FUNC: 2798 case STT_NOTYPE: 2799 case STT_OBJECT: 2800 if (symp->st_value == 0) 2801 continue; 2802 /* fallthrough */ 2803 case STT_TLS: 2804 if (symp->st_shndx != SHN_UNDEF) 2805 break; 2806 #ifndef __mips__ 2807 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2808 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2809 break; 2810 /* fallthrough */ 2811 #endif 2812 default: 2813 continue; 2814 } 2815 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2816 continue; 2817 2818 if (ventry == NULL) { 2819 if (obj->versyms != NULL) { 2820 verndx = VER_NDX(obj->versyms[symnum]); 2821 if (verndx > obj->vernum) { 2822 _rtld_error("%s: symbol %s references wrong version %d", 2823 obj->path, obj->strtab + symnum, verndx); 2824 continue; 2825 } 2826 /* 2827 * If we are not called from dlsym (i.e. this is a normal 2828 * relocation from unversioned binary, accept the symbol 2829 * immediately if it happens to have first version after 2830 * this shared object became versioned. Otherwise, if 2831 * symbol is versioned and not hidden, remember it. If it 2832 * is the only symbol with this name exported by the 2833 * shared object, it will be returned as a match at the 2834 * end of the function. If symbol is global (verndx < 2) 2835 * accept it unconditionally. 2836 */ 2837 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2838 return symp; 2839 else if (verndx >= VER_NDX_GIVEN) { 2840 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2841 if (vsymp == NULL) 2842 vsymp = symp; 2843 vcount ++; 2844 } 2845 continue; 2846 } 2847 } 2848 return symp; 2849 } else { 2850 if (obj->versyms == NULL) { 2851 if (object_match_name(obj, ventry->name)) { 2852 _rtld_error("%s: object %s should provide version %s for " 2853 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2854 obj->strtab + symnum); 2855 continue; 2856 } 2857 } else { 2858 verndx = VER_NDX(obj->versyms[symnum]); 2859 if (verndx > obj->vernum) { 2860 _rtld_error("%s: symbol %s references wrong version %d", 2861 obj->path, obj->strtab + symnum, verndx); 2862 continue; 2863 } 2864 if (obj->vertab[verndx].hash != ventry->hash || 2865 strcmp(obj->vertab[verndx].name, ventry->name)) { 2866 /* 2867 * Version does not match. Look if this is a global symbol 2868 * and if it is not hidden. If global symbol (verndx < 2) 2869 * is available, use it. Do not return symbol if we are 2870 * called by dlvsym, because dlvsym looks for a specific 2871 * version and default one is not what dlvsym wants. 2872 */ 2873 if ((flags & SYMLOOK_DLSYM) || 2874 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2875 (verndx >= VER_NDX_GIVEN)) 2876 continue; 2877 } 2878 } 2879 return symp; 2880 } 2881 } 2882 return (vcount == 1) ? vsymp : NULL; 2883 } 2884 2885 static void 2886 trace_loaded_objects(Obj_Entry *obj) 2887 { 2888 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2889 int c; 2890 2891 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2892 main_local = ""; 2893 2894 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2895 fmt1 = "\t%o => %p (%x)\n"; 2896 2897 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2898 fmt2 = "\t%o (%x)\n"; 2899 2900 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2901 2902 for (; obj; obj = obj->next) { 2903 Needed_Entry *needed; 2904 char *name, *path; 2905 bool is_lib; 2906 2907 if (list_containers && obj->needed != NULL) 2908 printf("%s:\n", obj->path); 2909 for (needed = obj->needed; needed; needed = needed->next) { 2910 if (needed->obj != NULL) { 2911 if (needed->obj->traced && !list_containers) 2912 continue; 2913 needed->obj->traced = true; 2914 path = needed->obj->path; 2915 } else 2916 path = "not found"; 2917 2918 name = (char *)obj->strtab + needed->name; 2919 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2920 2921 fmt = is_lib ? fmt1 : fmt2; 2922 while ((c = *fmt++) != '\0') { 2923 switch (c) { 2924 default: 2925 putchar(c); 2926 continue; 2927 case '\\': 2928 switch (c = *fmt) { 2929 case '\0': 2930 continue; 2931 case 'n': 2932 putchar('\n'); 2933 break; 2934 case 't': 2935 putchar('\t'); 2936 break; 2937 } 2938 break; 2939 case '%': 2940 switch (c = *fmt) { 2941 case '\0': 2942 continue; 2943 case '%': 2944 default: 2945 putchar(c); 2946 break; 2947 case 'A': 2948 printf("%s", main_local); 2949 break; 2950 case 'a': 2951 printf("%s", obj_main->path); 2952 break; 2953 case 'o': 2954 printf("%s", name); 2955 break; 2956 #if 0 2957 case 'm': 2958 printf("%d", sodp->sod_major); 2959 break; 2960 case 'n': 2961 printf("%d", sodp->sod_minor); 2962 break; 2963 #endif 2964 case 'p': 2965 printf("%s", path); 2966 break; 2967 case 'x': 2968 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2969 break; 2970 } 2971 break; 2972 } 2973 ++fmt; 2974 } 2975 } 2976 } 2977 } 2978 2979 /* 2980 * Unload a dlopened object and its dependencies from memory and from 2981 * our data structures. It is assumed that the DAG rooted in the 2982 * object has already been unreferenced, and that the object has a 2983 * reference count of 0. 2984 */ 2985 static void 2986 unload_object(Obj_Entry *root) 2987 { 2988 Obj_Entry *obj; 2989 Obj_Entry **linkp; 2990 2991 assert(root->refcount == 0); 2992 2993 /* 2994 * Pass over the DAG removing unreferenced objects from 2995 * appropriate lists. 2996 */ 2997 unlink_object(root); 2998 2999 /* Unmap all objects that are no longer referenced. */ 3000 linkp = &obj_list->next; 3001 while ((obj = *linkp) != NULL) { 3002 if (obj->refcount == 0) { 3003 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3004 obj->path); 3005 dbg("unloading \"%s\"", obj->path); 3006 munmap(obj->mapbase, obj->mapsize); 3007 linkmap_delete(obj); 3008 *linkp = obj->next; 3009 obj_count--; 3010 obj_free(obj); 3011 } else 3012 linkp = &obj->next; 3013 } 3014 obj_tail = linkp; 3015 } 3016 3017 static void 3018 unlink_object(Obj_Entry *root) 3019 { 3020 Objlist_Entry *elm; 3021 3022 if (root->refcount == 0) { 3023 /* Remove the object from the RTLD_GLOBAL list. */ 3024 objlist_remove(&list_global, root); 3025 3026 /* Remove the object from all objects' DAG lists. */ 3027 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3028 objlist_remove(&elm->obj->dldags, root); 3029 if (elm->obj != root) 3030 unlink_object(elm->obj); 3031 } 3032 } 3033 } 3034 3035 static void 3036 ref_dag(Obj_Entry *root) 3037 { 3038 Objlist_Entry *elm; 3039 3040 STAILQ_FOREACH(elm, &root->dagmembers, link) 3041 elm->obj->refcount++; 3042 } 3043 3044 static void 3045 unref_dag(Obj_Entry *root) 3046 { 3047 Objlist_Entry *elm; 3048 3049 STAILQ_FOREACH(elm, &root->dagmembers, link) 3050 elm->obj->refcount--; 3051 } 3052 3053 /* 3054 * Common code for MD __tls_get_addr(). 3055 */ 3056 void * 3057 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3058 { 3059 Elf_Addr* dtv = *dtvp; 3060 int lockstate; 3061 3062 /* Check dtv generation in case new modules have arrived */ 3063 if (dtv[0] != tls_dtv_generation) { 3064 Elf_Addr* newdtv; 3065 int to_copy; 3066 3067 lockstate = wlock_acquire(rtld_bind_lock); 3068 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3069 to_copy = dtv[1]; 3070 if (to_copy > tls_max_index) 3071 to_copy = tls_max_index; 3072 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3073 newdtv[0] = tls_dtv_generation; 3074 newdtv[1] = tls_max_index; 3075 free(dtv); 3076 wlock_release(rtld_bind_lock, lockstate); 3077 *dtvp = newdtv; 3078 } 3079 3080 /* Dynamically allocate module TLS if necessary */ 3081 if (!dtv[index + 1]) { 3082 /* Signal safe, wlock will block out signals. */ 3083 lockstate = wlock_acquire(rtld_bind_lock); 3084 if (!dtv[index + 1]) 3085 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3086 wlock_release(rtld_bind_lock, lockstate); 3087 } 3088 return (void*) (dtv[index + 1] + offset); 3089 } 3090 3091 /* XXX not sure what variants to use for arm. */ 3092 3093 #if defined(__ia64__) || defined(__powerpc__) 3094 3095 /* 3096 * Allocate Static TLS using the Variant I method. 3097 */ 3098 void * 3099 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3100 { 3101 Obj_Entry *obj; 3102 char *tcb; 3103 Elf_Addr **tls; 3104 Elf_Addr *dtv; 3105 Elf_Addr addr; 3106 int i; 3107 3108 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3109 return (oldtcb); 3110 3111 assert(tcbsize >= TLS_TCB_SIZE); 3112 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3113 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3114 3115 if (oldtcb != NULL) { 3116 memcpy(tls, oldtcb, tls_static_space); 3117 free(oldtcb); 3118 3119 /* Adjust the DTV. */ 3120 dtv = tls[0]; 3121 for (i = 0; i < dtv[1]; i++) { 3122 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3123 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3124 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3125 } 3126 } 3127 } else { 3128 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3129 tls[0] = dtv; 3130 dtv[0] = tls_dtv_generation; 3131 dtv[1] = tls_max_index; 3132 3133 for (obj = objs; obj; obj = obj->next) { 3134 if (obj->tlsoffset) { 3135 addr = (Elf_Addr)tls + obj->tlsoffset; 3136 memset((void*) (addr + obj->tlsinitsize), 3137 0, obj->tlssize - obj->tlsinitsize); 3138 if (obj->tlsinit) 3139 memcpy((void*) addr, obj->tlsinit, 3140 obj->tlsinitsize); 3141 dtv[obj->tlsindex + 1] = addr; 3142 } 3143 } 3144 } 3145 3146 return (tcb); 3147 } 3148 3149 void 3150 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3151 { 3152 Elf_Addr *dtv; 3153 Elf_Addr tlsstart, tlsend; 3154 int dtvsize, i; 3155 3156 assert(tcbsize >= TLS_TCB_SIZE); 3157 3158 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3159 tlsend = tlsstart + tls_static_space; 3160 3161 dtv = *(Elf_Addr **)tlsstart; 3162 dtvsize = dtv[1]; 3163 for (i = 0; i < dtvsize; i++) { 3164 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3165 free((void*)dtv[i+2]); 3166 } 3167 } 3168 free(dtv); 3169 free(tcb); 3170 } 3171 3172 #endif 3173 3174 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3175 defined(__arm__) || defined(__mips__) 3176 3177 /* 3178 * Allocate Static TLS using the Variant II method. 3179 */ 3180 void * 3181 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3182 { 3183 Obj_Entry *obj; 3184 size_t size; 3185 char *tls; 3186 Elf_Addr *dtv, *olddtv; 3187 Elf_Addr segbase, oldsegbase, addr; 3188 int i; 3189 3190 size = round(tls_static_space, tcbalign); 3191 3192 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3193 tls = calloc(1, size + tcbsize); 3194 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3195 3196 segbase = (Elf_Addr)(tls + size); 3197 ((Elf_Addr*)segbase)[0] = segbase; 3198 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3199 3200 dtv[0] = tls_dtv_generation; 3201 dtv[1] = tls_max_index; 3202 3203 if (oldtls) { 3204 /* 3205 * Copy the static TLS block over whole. 3206 */ 3207 oldsegbase = (Elf_Addr) oldtls; 3208 memcpy((void *)(segbase - tls_static_space), 3209 (const void *)(oldsegbase - tls_static_space), 3210 tls_static_space); 3211 3212 /* 3213 * If any dynamic TLS blocks have been created tls_get_addr(), 3214 * move them over. 3215 */ 3216 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3217 for (i = 0; i < olddtv[1]; i++) { 3218 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3219 dtv[i+2] = olddtv[i+2]; 3220 olddtv[i+2] = 0; 3221 } 3222 } 3223 3224 /* 3225 * We assume that this block was the one we created with 3226 * allocate_initial_tls(). 3227 */ 3228 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3229 } else { 3230 for (obj = objs; obj; obj = obj->next) { 3231 if (obj->tlsoffset) { 3232 addr = segbase - obj->tlsoffset; 3233 memset((void*) (addr + obj->tlsinitsize), 3234 0, obj->tlssize - obj->tlsinitsize); 3235 if (obj->tlsinit) 3236 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3237 dtv[obj->tlsindex + 1] = addr; 3238 } 3239 } 3240 } 3241 3242 return (void*) segbase; 3243 } 3244 3245 void 3246 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3247 { 3248 size_t size; 3249 Elf_Addr* dtv; 3250 int dtvsize, i; 3251 Elf_Addr tlsstart, tlsend; 3252 3253 /* 3254 * Figure out the size of the initial TLS block so that we can 3255 * find stuff which ___tls_get_addr() allocated dynamically. 3256 */ 3257 size = round(tls_static_space, tcbalign); 3258 3259 dtv = ((Elf_Addr**)tls)[1]; 3260 dtvsize = dtv[1]; 3261 tlsend = (Elf_Addr) tls; 3262 tlsstart = tlsend - size; 3263 for (i = 0; i < dtvsize; i++) { 3264 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3265 free((void*) dtv[i+2]); 3266 } 3267 } 3268 3269 free((void*) tlsstart); 3270 free((void*) dtv); 3271 } 3272 3273 #endif 3274 3275 /* 3276 * Allocate TLS block for module with given index. 3277 */ 3278 void * 3279 allocate_module_tls(int index) 3280 { 3281 Obj_Entry* obj; 3282 char* p; 3283 3284 for (obj = obj_list; obj; obj = obj->next) { 3285 if (obj->tlsindex == index) 3286 break; 3287 } 3288 if (!obj) { 3289 _rtld_error("Can't find module with TLS index %d", index); 3290 die(); 3291 } 3292 3293 p = malloc(obj->tlssize); 3294 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3295 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3296 3297 return p; 3298 } 3299 3300 bool 3301 allocate_tls_offset(Obj_Entry *obj) 3302 { 3303 size_t off; 3304 3305 if (obj->tls_done) 3306 return true; 3307 3308 if (obj->tlssize == 0) { 3309 obj->tls_done = true; 3310 return true; 3311 } 3312 3313 if (obj->tlsindex == 1) 3314 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3315 else 3316 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3317 obj->tlssize, obj->tlsalign); 3318 3319 /* 3320 * If we have already fixed the size of the static TLS block, we 3321 * must stay within that size. When allocating the static TLS, we 3322 * leave a small amount of space spare to be used for dynamically 3323 * loading modules which use static TLS. 3324 */ 3325 if (tls_static_space) { 3326 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3327 return false; 3328 } 3329 3330 tls_last_offset = obj->tlsoffset = off; 3331 tls_last_size = obj->tlssize; 3332 obj->tls_done = true; 3333 3334 return true; 3335 } 3336 3337 void 3338 free_tls_offset(Obj_Entry *obj) 3339 { 3340 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3341 defined(__arm__) || defined(__mips__) 3342 /* 3343 * If we were the last thing to allocate out of the static TLS 3344 * block, we give our space back to the 'allocator'. This is a 3345 * simplistic workaround to allow libGL.so.1 to be loaded and 3346 * unloaded multiple times. We only handle the Variant II 3347 * mechanism for now - this really needs a proper allocator. 3348 */ 3349 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3350 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3351 tls_last_offset -= obj->tlssize; 3352 tls_last_size = 0; 3353 } 3354 #endif 3355 } 3356 3357 void * 3358 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3359 { 3360 void *ret; 3361 int lockstate; 3362 3363 lockstate = wlock_acquire(rtld_bind_lock); 3364 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3365 wlock_release(rtld_bind_lock, lockstate); 3366 return (ret); 3367 } 3368 3369 void 3370 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3371 { 3372 int lockstate; 3373 3374 lockstate = wlock_acquire(rtld_bind_lock); 3375 free_tls(tcb, tcbsize, tcbalign); 3376 wlock_release(rtld_bind_lock, lockstate); 3377 } 3378 3379 static void 3380 object_add_name(Obj_Entry *obj, const char *name) 3381 { 3382 Name_Entry *entry; 3383 size_t len; 3384 3385 len = strlen(name); 3386 entry = malloc(sizeof(Name_Entry) + len); 3387 3388 if (entry != NULL) { 3389 strcpy(entry->name, name); 3390 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3391 } 3392 } 3393 3394 static int 3395 object_match_name(const Obj_Entry *obj, const char *name) 3396 { 3397 Name_Entry *entry; 3398 3399 STAILQ_FOREACH(entry, &obj->names, link) { 3400 if (strcmp(name, entry->name) == 0) 3401 return (1); 3402 } 3403 return (0); 3404 } 3405 3406 static Obj_Entry * 3407 locate_dependency(const Obj_Entry *obj, const char *name) 3408 { 3409 const Objlist_Entry *entry; 3410 const Needed_Entry *needed; 3411 3412 STAILQ_FOREACH(entry, &list_main, link) { 3413 if (object_match_name(entry->obj, name)) 3414 return entry->obj; 3415 } 3416 3417 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3418 if (needed->obj == NULL) 3419 continue; 3420 if (object_match_name(needed->obj, name)) 3421 return needed->obj; 3422 } 3423 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3424 obj->path, name); 3425 die(); 3426 } 3427 3428 static int 3429 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3430 const Elf_Vernaux *vna) 3431 { 3432 const Elf_Verdef *vd; 3433 const char *vername; 3434 3435 vername = refobj->strtab + vna->vna_name; 3436 vd = depobj->verdef; 3437 if (vd == NULL) { 3438 _rtld_error("%s: version %s required by %s not defined", 3439 depobj->path, vername, refobj->path); 3440 return (-1); 3441 } 3442 for (;;) { 3443 if (vd->vd_version != VER_DEF_CURRENT) { 3444 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3445 depobj->path, vd->vd_version); 3446 return (-1); 3447 } 3448 if (vna->vna_hash == vd->vd_hash) { 3449 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3450 ((char *)vd + vd->vd_aux); 3451 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3452 return (0); 3453 } 3454 if (vd->vd_next == 0) 3455 break; 3456 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3457 } 3458 if (vna->vna_flags & VER_FLG_WEAK) 3459 return (0); 3460 _rtld_error("%s: version %s required by %s not found", 3461 depobj->path, vername, refobj->path); 3462 return (-1); 3463 } 3464 3465 static int 3466 rtld_verify_object_versions(Obj_Entry *obj) 3467 { 3468 const Elf_Verneed *vn; 3469 const Elf_Verdef *vd; 3470 const Elf_Verdaux *vda; 3471 const Elf_Vernaux *vna; 3472 const Obj_Entry *depobj; 3473 int maxvernum, vernum; 3474 3475 maxvernum = 0; 3476 /* 3477 * Walk over defined and required version records and figure out 3478 * max index used by any of them. Do very basic sanity checking 3479 * while there. 3480 */ 3481 vn = obj->verneed; 3482 while (vn != NULL) { 3483 if (vn->vn_version != VER_NEED_CURRENT) { 3484 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3485 obj->path, vn->vn_version); 3486 return (-1); 3487 } 3488 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3489 for (;;) { 3490 vernum = VER_NEED_IDX(vna->vna_other); 3491 if (vernum > maxvernum) 3492 maxvernum = vernum; 3493 if (vna->vna_next == 0) 3494 break; 3495 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3496 } 3497 if (vn->vn_next == 0) 3498 break; 3499 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3500 } 3501 3502 vd = obj->verdef; 3503 while (vd != NULL) { 3504 if (vd->vd_version != VER_DEF_CURRENT) { 3505 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3506 obj->path, vd->vd_version); 3507 return (-1); 3508 } 3509 vernum = VER_DEF_IDX(vd->vd_ndx); 3510 if (vernum > maxvernum) 3511 maxvernum = vernum; 3512 if (vd->vd_next == 0) 3513 break; 3514 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3515 } 3516 3517 if (maxvernum == 0) 3518 return (0); 3519 3520 /* 3521 * Store version information in array indexable by version index. 3522 * Verify that object version requirements are satisfied along the 3523 * way. 3524 */ 3525 obj->vernum = maxvernum + 1; 3526 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3527 3528 vd = obj->verdef; 3529 while (vd != NULL) { 3530 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3531 vernum = VER_DEF_IDX(vd->vd_ndx); 3532 assert(vernum <= maxvernum); 3533 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3534 obj->vertab[vernum].hash = vd->vd_hash; 3535 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3536 obj->vertab[vernum].file = NULL; 3537 obj->vertab[vernum].flags = 0; 3538 } 3539 if (vd->vd_next == 0) 3540 break; 3541 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3542 } 3543 3544 vn = obj->verneed; 3545 while (vn != NULL) { 3546 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3547 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3548 for (;;) { 3549 if (check_object_provided_version(obj, depobj, vna)) 3550 return (-1); 3551 vernum = VER_NEED_IDX(vna->vna_other); 3552 assert(vernum <= maxvernum); 3553 obj->vertab[vernum].hash = vna->vna_hash; 3554 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3555 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3556 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3557 VER_INFO_HIDDEN : 0; 3558 if (vna->vna_next == 0) 3559 break; 3560 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3561 } 3562 if (vn->vn_next == 0) 3563 break; 3564 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3565 } 3566 return 0; 3567 } 3568 3569 static int 3570 rtld_verify_versions(const Objlist *objlist) 3571 { 3572 Objlist_Entry *entry; 3573 int rc; 3574 3575 rc = 0; 3576 STAILQ_FOREACH(entry, objlist, link) { 3577 /* 3578 * Skip dummy objects or objects that have their version requirements 3579 * already checked. 3580 */ 3581 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3582 continue; 3583 if (rtld_verify_object_versions(entry->obj) == -1) { 3584 rc = -1; 3585 if (ld_tracing == NULL) 3586 break; 3587 } 3588 } 3589 if (rc == 0 || ld_tracing != NULL) 3590 rc = rtld_verify_object_versions(&obj_rtld); 3591 return rc; 3592 } 3593 3594 const Ver_Entry * 3595 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3596 { 3597 Elf_Versym vernum; 3598 3599 if (obj->vertab) { 3600 vernum = VER_NDX(obj->versyms[symnum]); 3601 if (vernum >= obj->vernum) { 3602 _rtld_error("%s: symbol %s has wrong verneed value %d", 3603 obj->path, obj->strtab + symnum, vernum); 3604 } else if (obj->vertab[vernum].hash != 0) { 3605 return &obj->vertab[vernum]; 3606 } 3607 } 3608 return NULL; 3609 } 3610