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 *, int); 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 constants 1312 * cannot yet be accessed. 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 false); 1437 if (obj1 == NULL && !ld_tracing) 1438 return -1; 1439 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1440 dbg("obj %s nodelete", obj1->path); 1441 init_dag(obj1); 1442 ref_dag(obj1); 1443 obj1->ref_nodel = true; 1444 } 1445 } 1446 } 1447 1448 return 0; 1449 } 1450 1451 static int 1452 load_preload_objects(void) 1453 { 1454 char *p = ld_preload; 1455 static const char delim[] = " \t:;"; 1456 1457 if (p == NULL) 1458 return 0; 1459 1460 p += strspn(p, delim); 1461 while (*p != '\0') { 1462 size_t len = strcspn(p, delim); 1463 char savech; 1464 1465 savech = p[len]; 1466 p[len] = '\0'; 1467 if (load_object(p, NULL, false) == NULL) 1468 return -1; /* XXX - cleanup */ 1469 p[len] = savech; 1470 p += len; 1471 p += strspn(p, delim); 1472 } 1473 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1474 return 0; 1475 } 1476 1477 /* 1478 * Load a shared object into memory, if it is not already loaded. 1479 * 1480 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1481 * on failure. 1482 */ 1483 static Obj_Entry * 1484 load_object(const char *name, const Obj_Entry *refobj, int noload) 1485 { 1486 Obj_Entry *obj; 1487 int fd = -1; 1488 struct stat sb; 1489 char *path; 1490 1491 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1492 if (object_match_name(obj, name)) 1493 return obj; 1494 1495 path = find_library(name, refobj); 1496 if (path == NULL) 1497 return NULL; 1498 1499 /* 1500 * If we didn't find a match by pathname, open the file and check 1501 * again by device and inode. This avoids false mismatches caused 1502 * by multiple links or ".." in pathnames. 1503 * 1504 * To avoid a race, we open the file and use fstat() rather than 1505 * using stat(). 1506 */ 1507 if ((fd = open(path, O_RDONLY)) == -1) { 1508 _rtld_error("Cannot open \"%s\"", path); 1509 free(path); 1510 return NULL; 1511 } 1512 if (fstat(fd, &sb) == -1) { 1513 _rtld_error("Cannot fstat \"%s\"", path); 1514 close(fd); 1515 free(path); 1516 return NULL; 1517 } 1518 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1519 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1520 close(fd); 1521 break; 1522 } 1523 } 1524 if (obj != NULL) { 1525 object_add_name(obj, name); 1526 free(path); 1527 close(fd); 1528 return obj; 1529 } 1530 if (noload) 1531 return (NULL); 1532 1533 /* First use of this object, so we must map it in */ 1534 obj = do_load_object(fd, name, path, &sb); 1535 if (obj == NULL) 1536 free(path); 1537 close(fd); 1538 1539 return obj; 1540 } 1541 1542 static Obj_Entry * 1543 do_load_object(int fd, const char *name, char *path, struct stat *sbp) 1544 { 1545 Obj_Entry *obj; 1546 struct statfs fs; 1547 1548 /* 1549 * but first, make sure that environment variables haven't been 1550 * used to circumvent the noexec flag on a filesystem. 1551 */ 1552 if (dangerous_ld_env) { 1553 if (fstatfs(fd, &fs) != 0) { 1554 _rtld_error("Cannot fstatfs \"%s\"", path); 1555 return NULL; 1556 } 1557 if (fs.f_flags & MNT_NOEXEC) { 1558 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1559 return NULL; 1560 } 1561 } 1562 dbg("loading \"%s\"", path); 1563 obj = map_object(fd, path, sbp); 1564 if (obj == NULL) 1565 return NULL; 1566 1567 object_add_name(obj, name); 1568 obj->path = path; 1569 digest_dynamic(obj, 0); 1570 1571 *obj_tail = obj; 1572 obj_tail = &obj->next; 1573 obj_count++; 1574 obj_loads++; 1575 linkmap_add(obj); /* for GDB & dlinfo() */ 1576 1577 dbg(" %p .. %p: %s", obj->mapbase, 1578 obj->mapbase + obj->mapsize - 1, obj->path); 1579 if (obj->textrel) 1580 dbg(" WARNING: %s has impure text", obj->path); 1581 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1582 obj->path); 1583 1584 return obj; 1585 } 1586 1587 static Obj_Entry * 1588 obj_from_addr(const void *addr) 1589 { 1590 Obj_Entry *obj; 1591 1592 for (obj = obj_list; obj != NULL; obj = obj->next) { 1593 if (addr < (void *) obj->mapbase) 1594 continue; 1595 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1596 return obj; 1597 } 1598 return NULL; 1599 } 1600 1601 /* 1602 * Call the finalization functions for each of the objects in "list" 1603 * which are unreferenced. All of the objects are expected to have 1604 * non-NULL fini functions. 1605 */ 1606 static void 1607 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1608 { 1609 Objlist_Entry *elm, *elm_tmp; 1610 char *saved_msg; 1611 1612 /* 1613 * Preserve the current error message since a fini function might 1614 * call into the dynamic linker and overwrite it. 1615 */ 1616 saved_msg = errmsg_save(); 1617 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1618 if (elm->obj->refcount == 0 || force) { 1619 dbg("calling fini function for %s at %p", elm->obj->path, 1620 (void *)elm->obj->fini); 1621 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1622 elm->obj->path); 1623 /* Remove object from fini list to prevent recursive invocation. */ 1624 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1625 wlock_release(rtld_bind_lock, *lockstate); 1626 call_initfini_pointer(elm->obj, elm->obj->fini); 1627 *lockstate = wlock_acquire(rtld_bind_lock); 1628 /* No need to free anything if process is going down. */ 1629 if (!force) 1630 free(elm); 1631 } 1632 } 1633 errmsg_restore(saved_msg); 1634 } 1635 1636 /* 1637 * Call the initialization functions for each of the objects in 1638 * "list". All of the objects are expected to have non-NULL init 1639 * functions. 1640 */ 1641 static void 1642 objlist_call_init(Objlist *list, int *lockstate) 1643 { 1644 Objlist_Entry *elm; 1645 Obj_Entry *obj; 1646 char *saved_msg; 1647 1648 /* 1649 * Clean init_scanned flag so that objects can be rechecked and 1650 * possibly initialized earlier if any of vectors called below 1651 * cause the change by using dlopen. 1652 */ 1653 for (obj = obj_list; obj != NULL; obj = obj->next) 1654 obj->init_scanned = false; 1655 1656 /* 1657 * Preserve the current error message since an init function might 1658 * call into the dynamic linker and overwrite it. 1659 */ 1660 saved_msg = errmsg_save(); 1661 STAILQ_FOREACH(elm, list, link) { 1662 if (elm->obj->init_done) /* Initialized early. */ 1663 continue; 1664 dbg("calling init function for %s at %p", elm->obj->path, 1665 (void *)elm->obj->init); 1666 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1667 elm->obj->path); 1668 /* 1669 * Race: other thread might try to use this object before current 1670 * one completes the initilization. Not much can be done here 1671 * without better locking. 1672 */ 1673 elm->obj->init_done = true; 1674 wlock_release(rtld_bind_lock, *lockstate); 1675 call_initfini_pointer(elm->obj, elm->obj->init); 1676 *lockstate = wlock_acquire(rtld_bind_lock); 1677 } 1678 errmsg_restore(saved_msg); 1679 } 1680 1681 static void 1682 objlist_clear(Objlist *list) 1683 { 1684 Objlist_Entry *elm; 1685 1686 while (!STAILQ_EMPTY(list)) { 1687 elm = STAILQ_FIRST(list); 1688 STAILQ_REMOVE_HEAD(list, link); 1689 free(elm); 1690 } 1691 } 1692 1693 static Objlist_Entry * 1694 objlist_find(Objlist *list, const Obj_Entry *obj) 1695 { 1696 Objlist_Entry *elm; 1697 1698 STAILQ_FOREACH(elm, list, link) 1699 if (elm->obj == obj) 1700 return elm; 1701 return NULL; 1702 } 1703 1704 static void 1705 objlist_init(Objlist *list) 1706 { 1707 STAILQ_INIT(list); 1708 } 1709 1710 static void 1711 objlist_push_head(Objlist *list, Obj_Entry *obj) 1712 { 1713 Objlist_Entry *elm; 1714 1715 elm = NEW(Objlist_Entry); 1716 elm->obj = obj; 1717 STAILQ_INSERT_HEAD(list, elm, link); 1718 } 1719 1720 static void 1721 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1722 { 1723 Objlist_Entry *elm; 1724 1725 elm = NEW(Objlist_Entry); 1726 elm->obj = obj; 1727 STAILQ_INSERT_TAIL(list, elm, link); 1728 } 1729 1730 static void 1731 objlist_remove(Objlist *list, Obj_Entry *obj) 1732 { 1733 Objlist_Entry *elm; 1734 1735 if ((elm = objlist_find(list, obj)) != NULL) { 1736 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1737 free(elm); 1738 } 1739 } 1740 1741 /* 1742 * Relocate newly-loaded shared objects. The argument is a pointer to 1743 * the Obj_Entry for the first such object. All objects from the first 1744 * to the end of the list of objects are relocated. Returns 0 on success, 1745 * or -1 on failure. 1746 */ 1747 static int 1748 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1749 { 1750 Obj_Entry *obj; 1751 1752 for (obj = first; obj != NULL; obj = obj->next) { 1753 if (obj != rtldobj) 1754 dbg("relocating \"%s\"", obj->path); 1755 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1756 obj->symtab == NULL || obj->strtab == NULL) { 1757 _rtld_error("%s: Shared object has no run-time symbol table", 1758 obj->path); 1759 return -1; 1760 } 1761 1762 if (obj->textrel) { 1763 /* There are relocations to the write-protected text segment. */ 1764 if (mprotect(obj->mapbase, obj->textsize, 1765 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1766 _rtld_error("%s: Cannot write-enable text segment: %s", 1767 obj->path, strerror(errno)); 1768 return -1; 1769 } 1770 } 1771 1772 /* Process the non-PLT relocations. */ 1773 if (reloc_non_plt(obj, rtldobj)) 1774 return -1; 1775 1776 if (obj->textrel) { /* Re-protected the text segment. */ 1777 if (mprotect(obj->mapbase, obj->textsize, 1778 PROT_READ|PROT_EXEC) == -1) { 1779 _rtld_error("%s: Cannot write-protect text segment: %s", 1780 obj->path, strerror(errno)); 1781 return -1; 1782 } 1783 } 1784 1785 /* Process the PLT relocations. */ 1786 if (reloc_plt(obj) == -1) 1787 return -1; 1788 /* Relocate the jump slots if we are doing immediate binding. */ 1789 if (obj->bind_now || bind_now) 1790 if (reloc_jmpslots(obj) == -1) 1791 return -1; 1792 1793 1794 /* 1795 * Set up the magic number and version in the Obj_Entry. These 1796 * were checked in the crt1.o from the original ElfKit, so we 1797 * set them for backward compatibility. 1798 */ 1799 obj->magic = RTLD_MAGIC; 1800 obj->version = RTLD_VERSION; 1801 1802 /* Set the special PLT or GOT entries. */ 1803 init_pltgot(obj); 1804 } 1805 1806 return 0; 1807 } 1808 1809 /* 1810 * Cleanup procedure. It will be called (by the atexit mechanism) just 1811 * before the process exits. 1812 */ 1813 static void 1814 rtld_exit(void) 1815 { 1816 int lockstate; 1817 1818 lockstate = wlock_acquire(rtld_bind_lock); 1819 dbg("rtld_exit()"); 1820 objlist_call_fini(&list_fini, true, &lockstate); 1821 /* No need to remove the items from the list, since we are exiting. */ 1822 if (!libmap_disable) 1823 lm_fini(); 1824 wlock_release(rtld_bind_lock, lockstate); 1825 } 1826 1827 static void * 1828 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1829 { 1830 #ifdef COMPAT_32BIT 1831 const char *trans; 1832 #endif 1833 if (path == NULL) 1834 return (NULL); 1835 1836 path += strspn(path, ":;"); 1837 while (*path != '\0') { 1838 size_t len; 1839 char *res; 1840 1841 len = strcspn(path, ":;"); 1842 #ifdef COMPAT_32BIT 1843 trans = lm_findn(NULL, path, len); 1844 if (trans) 1845 res = callback(trans, strlen(trans), arg); 1846 else 1847 #endif 1848 res = callback(path, len, arg); 1849 1850 if (res != NULL) 1851 return (res); 1852 1853 path += len; 1854 path += strspn(path, ":;"); 1855 } 1856 1857 return (NULL); 1858 } 1859 1860 struct try_library_args { 1861 const char *name; 1862 size_t namelen; 1863 char *buffer; 1864 size_t buflen; 1865 }; 1866 1867 static void * 1868 try_library_path(const char *dir, size_t dirlen, void *param) 1869 { 1870 struct try_library_args *arg; 1871 1872 arg = param; 1873 if (*dir == '/' || trust) { 1874 char *pathname; 1875 1876 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1877 return (NULL); 1878 1879 pathname = arg->buffer; 1880 strncpy(pathname, dir, dirlen); 1881 pathname[dirlen] = '/'; 1882 strcpy(pathname + dirlen + 1, arg->name); 1883 1884 dbg(" Trying \"%s\"", pathname); 1885 if (access(pathname, F_OK) == 0) { /* We found it */ 1886 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1887 strcpy(pathname, arg->buffer); 1888 return (pathname); 1889 } 1890 } 1891 return (NULL); 1892 } 1893 1894 static char * 1895 search_library_path(const char *name, const char *path) 1896 { 1897 char *p; 1898 struct try_library_args arg; 1899 1900 if (path == NULL) 1901 return NULL; 1902 1903 arg.name = name; 1904 arg.namelen = strlen(name); 1905 arg.buffer = xmalloc(PATH_MAX); 1906 arg.buflen = PATH_MAX; 1907 1908 p = path_enumerate(path, try_library_path, &arg); 1909 1910 free(arg.buffer); 1911 1912 return (p); 1913 } 1914 1915 int 1916 dlclose(void *handle) 1917 { 1918 Obj_Entry *root; 1919 int lockstate; 1920 1921 lockstate = wlock_acquire(rtld_bind_lock); 1922 root = dlcheck(handle); 1923 if (root == NULL) { 1924 wlock_release(rtld_bind_lock, lockstate); 1925 return -1; 1926 } 1927 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1928 root->path); 1929 1930 /* Unreference the object and its dependencies. */ 1931 root->dl_refcount--; 1932 1933 unref_dag(root); 1934 1935 if (root->refcount == 0) { 1936 /* 1937 * The object is no longer referenced, so we must unload it. 1938 * First, call the fini functions. 1939 */ 1940 objlist_call_fini(&list_fini, false, &lockstate); 1941 1942 /* Finish cleaning up the newly-unreferenced objects. */ 1943 GDB_STATE(RT_DELETE,&root->linkmap); 1944 unload_object(root); 1945 GDB_STATE(RT_CONSISTENT,NULL); 1946 } 1947 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1948 wlock_release(rtld_bind_lock, lockstate); 1949 return 0; 1950 } 1951 1952 const char * 1953 dlerror(void) 1954 { 1955 char *msg = error_message; 1956 error_message = NULL; 1957 return msg; 1958 } 1959 1960 /* 1961 * This function is deprecated and has no effect. 1962 */ 1963 void 1964 dllockinit(void *context, 1965 void *(*lock_create)(void *context), 1966 void (*rlock_acquire)(void *lock), 1967 void (*wlock_acquire)(void *lock), 1968 void (*lock_release)(void *lock), 1969 void (*lock_destroy)(void *lock), 1970 void (*context_destroy)(void *context)) 1971 { 1972 static void *cur_context; 1973 static void (*cur_context_destroy)(void *); 1974 1975 /* Just destroy the context from the previous call, if necessary. */ 1976 if (cur_context_destroy != NULL) 1977 cur_context_destroy(cur_context); 1978 cur_context = context; 1979 cur_context_destroy = context_destroy; 1980 } 1981 1982 void * 1983 dlopen(const char *name, int mode) 1984 { 1985 Obj_Entry **old_obj_tail; 1986 Obj_Entry *obj; 1987 Objlist initlist; 1988 int result, lockstate, nodelete, noload; 1989 1990 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 1991 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1992 if (ld_tracing != NULL) 1993 environ = (char **)*get_program_var_addr("environ"); 1994 nodelete = mode & RTLD_NODELETE; 1995 noload = mode & RTLD_NOLOAD; 1996 1997 objlist_init(&initlist); 1998 1999 lockstate = wlock_acquire(rtld_bind_lock); 2000 GDB_STATE(RT_ADD,NULL); 2001 2002 old_obj_tail = obj_tail; 2003 obj = NULL; 2004 if (name == NULL) { 2005 obj = obj_main; 2006 obj->refcount++; 2007 } else { 2008 obj = load_object(name, obj_main, noload); 2009 } 2010 2011 if (obj) { 2012 obj->dl_refcount++; 2013 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2014 objlist_push_tail(&list_global, obj); 2015 mode &= RTLD_MODEMASK; 2016 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2017 assert(*old_obj_tail == obj); 2018 result = load_needed_objects(obj); 2019 init_dag(obj); 2020 if (result != -1) 2021 result = rtld_verify_versions(&obj->dagmembers); 2022 if (result != -1 && ld_tracing) 2023 goto trace; 2024 if (result == -1 || 2025 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2026 obj->dl_refcount--; 2027 unref_dag(obj); 2028 if (obj->refcount == 0) 2029 unload_object(obj); 2030 obj = NULL; 2031 } else { 2032 /* Make list of init functions to call. */ 2033 initlist_add_objects(obj, &obj->next, &initlist); 2034 } 2035 } else { 2036 2037 /* Bump the reference counts for objects on this DAG. */ 2038 ref_dag(obj); 2039 2040 if (ld_tracing) 2041 goto trace; 2042 } 2043 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2044 dbg("obj %s nodelete", obj->path); 2045 ref_dag(obj); 2046 obj->z_nodelete = obj->ref_nodel = true; 2047 } 2048 } 2049 2050 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2051 name); 2052 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2053 2054 /* Call the init functions. */ 2055 objlist_call_init(&initlist, &lockstate); 2056 objlist_clear(&initlist); 2057 wlock_release(rtld_bind_lock, lockstate); 2058 return obj; 2059 trace: 2060 trace_loaded_objects(obj); 2061 wlock_release(rtld_bind_lock, lockstate); 2062 exit(0); 2063 } 2064 2065 static void * 2066 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2067 int flags) 2068 { 2069 DoneList donelist; 2070 const Obj_Entry *obj, *defobj; 2071 const Elf_Sym *def, *symp; 2072 unsigned long hash; 2073 int lockstate; 2074 2075 hash = elf_hash(name); 2076 def = NULL; 2077 defobj = NULL; 2078 flags |= SYMLOOK_IN_PLT; 2079 2080 lockstate = rlock_acquire(rtld_bind_lock); 2081 if (handle == NULL || handle == RTLD_NEXT || 2082 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2083 2084 if ((obj = obj_from_addr(retaddr)) == NULL) { 2085 _rtld_error("Cannot determine caller's shared object"); 2086 rlock_release(rtld_bind_lock, lockstate); 2087 return NULL; 2088 } 2089 if (handle == NULL) { /* Just the caller's shared object. */ 2090 def = symlook_obj(name, hash, obj, ve, flags); 2091 defobj = obj; 2092 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2093 handle == RTLD_SELF) { /* ... caller included */ 2094 if (handle == RTLD_NEXT) 2095 obj = obj->next; 2096 for (; obj != NULL; obj = obj->next) { 2097 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2098 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2099 def = symp; 2100 defobj = obj; 2101 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2102 break; 2103 } 2104 } 2105 } 2106 /* 2107 * Search the dynamic linker itself, and possibly resolve the 2108 * symbol from there. This is how the application links to 2109 * dynamic linker services such as dlopen. Only the values listed 2110 * in the "exports" array can be resolved from the dynamic linker. 2111 */ 2112 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2113 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2114 if (symp != NULL && is_exported(symp)) { 2115 def = symp; 2116 defobj = &obj_rtld; 2117 } 2118 } 2119 } else { 2120 assert(handle == RTLD_DEFAULT); 2121 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2122 } 2123 } else { 2124 if ((obj = dlcheck(handle)) == NULL) { 2125 rlock_release(rtld_bind_lock, lockstate); 2126 return NULL; 2127 } 2128 2129 donelist_init(&donelist); 2130 if (obj->mainprog) { 2131 /* Search main program and all libraries loaded by it. */ 2132 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2133 &donelist); 2134 2135 /* 2136 * We do not distinguish between 'main' object and global scope. 2137 * If symbol is not defined by objects loaded at startup, continue 2138 * search among dynamically loaded objects with RTLD_GLOBAL 2139 * scope. 2140 */ 2141 if (def == NULL) 2142 def = symlook_list(name, hash, &list_global, &defobj, ve, 2143 flags, &donelist); 2144 } else { 2145 Needed_Entry fake; 2146 2147 /* Search the whole DAG rooted at the given object. */ 2148 fake.next = NULL; 2149 fake.obj = (Obj_Entry *)obj; 2150 fake.name = 0; 2151 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2152 &donelist); 2153 } 2154 } 2155 2156 if (def != NULL) { 2157 rlock_release(rtld_bind_lock, lockstate); 2158 2159 /* 2160 * The value required by the caller is derived from the value 2161 * of the symbol. For the ia64 architecture, we need to 2162 * construct a function descriptor which the caller can use to 2163 * call the function with the right 'gp' value. For other 2164 * architectures and for non-functions, the value is simply 2165 * the relocated value of the symbol. 2166 */ 2167 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2168 return make_function_pointer(def, defobj); 2169 else 2170 return defobj->relocbase + def->st_value; 2171 } 2172 2173 _rtld_error("Undefined symbol \"%s\"", name); 2174 rlock_release(rtld_bind_lock, lockstate); 2175 return NULL; 2176 } 2177 2178 void * 2179 dlsym(void *handle, const char *name) 2180 { 2181 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2182 SYMLOOK_DLSYM); 2183 } 2184 2185 dlfunc_t 2186 dlfunc(void *handle, const char *name) 2187 { 2188 union { 2189 void *d; 2190 dlfunc_t f; 2191 } rv; 2192 2193 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2194 SYMLOOK_DLSYM); 2195 return (rv.f); 2196 } 2197 2198 void * 2199 dlvsym(void *handle, const char *name, const char *version) 2200 { 2201 Ver_Entry ventry; 2202 2203 ventry.name = version; 2204 ventry.file = NULL; 2205 ventry.hash = elf_hash(version); 2206 ventry.flags= 0; 2207 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2208 SYMLOOK_DLSYM); 2209 } 2210 2211 int 2212 dladdr(const void *addr, Dl_info *info) 2213 { 2214 const Obj_Entry *obj; 2215 const Elf_Sym *def; 2216 void *symbol_addr; 2217 unsigned long symoffset; 2218 int lockstate; 2219 2220 lockstate = rlock_acquire(rtld_bind_lock); 2221 obj = obj_from_addr(addr); 2222 if (obj == NULL) { 2223 _rtld_error("No shared object contains address"); 2224 rlock_release(rtld_bind_lock, lockstate); 2225 return 0; 2226 } 2227 info->dli_fname = obj->path; 2228 info->dli_fbase = obj->mapbase; 2229 info->dli_saddr = (void *)0; 2230 info->dli_sname = NULL; 2231 2232 /* 2233 * Walk the symbol list looking for the symbol whose address is 2234 * closest to the address sent in. 2235 */ 2236 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2237 def = obj->symtab + symoffset; 2238 2239 /* 2240 * For skip the symbol if st_shndx is either SHN_UNDEF or 2241 * SHN_COMMON. 2242 */ 2243 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2244 continue; 2245 2246 /* 2247 * If the symbol is greater than the specified address, or if it 2248 * is further away from addr than the current nearest symbol, 2249 * then reject it. 2250 */ 2251 symbol_addr = obj->relocbase + def->st_value; 2252 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2253 continue; 2254 2255 /* Update our idea of the nearest symbol. */ 2256 info->dli_sname = obj->strtab + def->st_name; 2257 info->dli_saddr = symbol_addr; 2258 2259 /* Exact match? */ 2260 if (info->dli_saddr == addr) 2261 break; 2262 } 2263 rlock_release(rtld_bind_lock, lockstate); 2264 return 1; 2265 } 2266 2267 int 2268 dlinfo(void *handle, int request, void *p) 2269 { 2270 const Obj_Entry *obj; 2271 int error, lockstate; 2272 2273 lockstate = rlock_acquire(rtld_bind_lock); 2274 2275 if (handle == NULL || handle == RTLD_SELF) { 2276 void *retaddr; 2277 2278 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2279 if ((obj = obj_from_addr(retaddr)) == NULL) 2280 _rtld_error("Cannot determine caller's shared object"); 2281 } else 2282 obj = dlcheck(handle); 2283 2284 if (obj == NULL) { 2285 rlock_release(rtld_bind_lock, lockstate); 2286 return (-1); 2287 } 2288 2289 error = 0; 2290 switch (request) { 2291 case RTLD_DI_LINKMAP: 2292 *((struct link_map const **)p) = &obj->linkmap; 2293 break; 2294 case RTLD_DI_ORIGIN: 2295 error = rtld_dirname(obj->path, p); 2296 break; 2297 2298 case RTLD_DI_SERINFOSIZE: 2299 case RTLD_DI_SERINFO: 2300 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2301 break; 2302 2303 default: 2304 _rtld_error("Invalid request %d passed to dlinfo()", request); 2305 error = -1; 2306 } 2307 2308 rlock_release(rtld_bind_lock, lockstate); 2309 2310 return (error); 2311 } 2312 2313 int 2314 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2315 { 2316 struct dl_phdr_info phdr_info; 2317 const Obj_Entry *obj; 2318 int error, bind_lockstate, phdr_lockstate; 2319 2320 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2321 bind_lockstate = rlock_acquire(rtld_bind_lock); 2322 2323 error = 0; 2324 2325 for (obj = obj_list; obj != NULL; obj = obj->next) { 2326 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2327 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2328 STAILQ_FIRST(&obj->names)->name : obj->path; 2329 phdr_info.dlpi_phdr = obj->phdr; 2330 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2331 phdr_info.dlpi_tls_modid = obj->tlsindex; 2332 phdr_info.dlpi_tls_data = obj->tlsinit; 2333 phdr_info.dlpi_adds = obj_loads; 2334 phdr_info.dlpi_subs = obj_loads - obj_count; 2335 2336 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2337 break; 2338 2339 } 2340 rlock_release(rtld_bind_lock, bind_lockstate); 2341 wlock_release(rtld_phdr_lock, phdr_lockstate); 2342 2343 return (error); 2344 } 2345 2346 struct fill_search_info_args { 2347 int request; 2348 unsigned int flags; 2349 Dl_serinfo *serinfo; 2350 Dl_serpath *serpath; 2351 char *strspace; 2352 }; 2353 2354 static void * 2355 fill_search_info(const char *dir, size_t dirlen, void *param) 2356 { 2357 struct fill_search_info_args *arg; 2358 2359 arg = param; 2360 2361 if (arg->request == RTLD_DI_SERINFOSIZE) { 2362 arg->serinfo->dls_cnt ++; 2363 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2364 } else { 2365 struct dl_serpath *s_entry; 2366 2367 s_entry = arg->serpath; 2368 s_entry->dls_name = arg->strspace; 2369 s_entry->dls_flags = arg->flags; 2370 2371 strncpy(arg->strspace, dir, dirlen); 2372 arg->strspace[dirlen] = '\0'; 2373 2374 arg->strspace += dirlen + 1; 2375 arg->serpath++; 2376 } 2377 2378 return (NULL); 2379 } 2380 2381 static int 2382 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2383 { 2384 struct dl_serinfo _info; 2385 struct fill_search_info_args args; 2386 2387 args.request = RTLD_DI_SERINFOSIZE; 2388 args.serinfo = &_info; 2389 2390 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2391 _info.dls_cnt = 0; 2392 2393 path_enumerate(ld_library_path, fill_search_info, &args); 2394 path_enumerate(obj->rpath, fill_search_info, &args); 2395 path_enumerate(gethints(), fill_search_info, &args); 2396 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2397 2398 2399 if (request == RTLD_DI_SERINFOSIZE) { 2400 info->dls_size = _info.dls_size; 2401 info->dls_cnt = _info.dls_cnt; 2402 return (0); 2403 } 2404 2405 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2406 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2407 return (-1); 2408 } 2409 2410 args.request = RTLD_DI_SERINFO; 2411 args.serinfo = info; 2412 args.serpath = &info->dls_serpath[0]; 2413 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2414 2415 args.flags = LA_SER_LIBPATH; 2416 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2417 return (-1); 2418 2419 args.flags = LA_SER_RUNPATH; 2420 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2421 return (-1); 2422 2423 args.flags = LA_SER_CONFIG; 2424 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2425 return (-1); 2426 2427 args.flags = LA_SER_DEFAULT; 2428 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2429 return (-1); 2430 return (0); 2431 } 2432 2433 static int 2434 rtld_dirname(const char *path, char *bname) 2435 { 2436 const char *endp; 2437 2438 /* Empty or NULL string gets treated as "." */ 2439 if (path == NULL || *path == '\0') { 2440 bname[0] = '.'; 2441 bname[1] = '\0'; 2442 return (0); 2443 } 2444 2445 /* Strip trailing slashes */ 2446 endp = path + strlen(path) - 1; 2447 while (endp > path && *endp == '/') 2448 endp--; 2449 2450 /* Find the start of the dir */ 2451 while (endp > path && *endp != '/') 2452 endp--; 2453 2454 /* Either the dir is "/" or there are no slashes */ 2455 if (endp == path) { 2456 bname[0] = *endp == '/' ? '/' : '.'; 2457 bname[1] = '\0'; 2458 return (0); 2459 } else { 2460 do { 2461 endp--; 2462 } while (endp > path && *endp == '/'); 2463 } 2464 2465 if (endp - path + 2 > PATH_MAX) 2466 { 2467 _rtld_error("Filename is too long: %s", path); 2468 return(-1); 2469 } 2470 2471 strncpy(bname, path, endp - path + 1); 2472 bname[endp - path + 1] = '\0'; 2473 return (0); 2474 } 2475 2476 static int 2477 rtld_dirname_abs(const char *path, char *base) 2478 { 2479 char base_rel[PATH_MAX]; 2480 2481 if (rtld_dirname(path, base) == -1) 2482 return (-1); 2483 if (base[0] == '/') 2484 return (0); 2485 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2486 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2487 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2488 return (-1); 2489 strcpy(base, base_rel); 2490 return (0); 2491 } 2492 2493 static void 2494 linkmap_add(Obj_Entry *obj) 2495 { 2496 struct link_map *l = &obj->linkmap; 2497 struct link_map *prev; 2498 2499 obj->linkmap.l_name = obj->path; 2500 obj->linkmap.l_addr = obj->mapbase; 2501 obj->linkmap.l_ld = obj->dynamic; 2502 #ifdef __mips__ 2503 /* GDB needs load offset on MIPS to use the symbols */ 2504 obj->linkmap.l_offs = obj->relocbase; 2505 #endif 2506 2507 if (r_debug.r_map == NULL) { 2508 r_debug.r_map = l; 2509 return; 2510 } 2511 2512 /* 2513 * Scan to the end of the list, but not past the entry for the 2514 * dynamic linker, which we want to keep at the very end. 2515 */ 2516 for (prev = r_debug.r_map; 2517 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2518 prev = prev->l_next) 2519 ; 2520 2521 /* Link in the new entry. */ 2522 l->l_prev = prev; 2523 l->l_next = prev->l_next; 2524 if (l->l_next != NULL) 2525 l->l_next->l_prev = l; 2526 prev->l_next = l; 2527 } 2528 2529 static void 2530 linkmap_delete(Obj_Entry *obj) 2531 { 2532 struct link_map *l = &obj->linkmap; 2533 2534 if (l->l_prev == NULL) { 2535 if ((r_debug.r_map = l->l_next) != NULL) 2536 l->l_next->l_prev = NULL; 2537 return; 2538 } 2539 2540 if ((l->l_prev->l_next = l->l_next) != NULL) 2541 l->l_next->l_prev = l->l_prev; 2542 } 2543 2544 /* 2545 * Function for the debugger to set a breakpoint on to gain control. 2546 * 2547 * The two parameters allow the debugger to easily find and determine 2548 * what the runtime loader is doing and to whom it is doing it. 2549 * 2550 * When the loadhook trap is hit (r_debug_state, set at program 2551 * initialization), the arguments can be found on the stack: 2552 * 2553 * +8 struct link_map *m 2554 * +4 struct r_debug *rd 2555 * +0 RetAddr 2556 */ 2557 void 2558 r_debug_state(struct r_debug* rd, struct link_map *m) 2559 { 2560 } 2561 2562 /* 2563 * Get address of the pointer variable in the main program. 2564 */ 2565 static const void ** 2566 get_program_var_addr(const char *name) 2567 { 2568 const Obj_Entry *obj; 2569 unsigned long hash; 2570 2571 hash = elf_hash(name); 2572 for (obj = obj_main; obj != NULL; obj = obj->next) { 2573 const Elf_Sym *def; 2574 2575 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2576 const void **addr; 2577 2578 addr = (const void **)(obj->relocbase + def->st_value); 2579 return addr; 2580 } 2581 } 2582 return NULL; 2583 } 2584 2585 /* 2586 * Set a pointer variable in the main program to the given value. This 2587 * is used to set key variables such as "environ" before any of the 2588 * init functions are called. 2589 */ 2590 static void 2591 set_program_var(const char *name, const void *value) 2592 { 2593 const void **addr; 2594 2595 if ((addr = get_program_var_addr(name)) != NULL) { 2596 dbg("\"%s\": *%p <-- %p", name, addr, value); 2597 *addr = value; 2598 } 2599 } 2600 2601 /* 2602 * Given a symbol name in a referencing object, find the corresponding 2603 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2604 * no definition was found. Returns a pointer to the Obj_Entry of the 2605 * defining object via the reference parameter DEFOBJ_OUT. 2606 */ 2607 static const Elf_Sym * 2608 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2609 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2610 { 2611 DoneList donelist; 2612 const Elf_Sym *def; 2613 const Elf_Sym *symp; 2614 const Obj_Entry *obj; 2615 const Obj_Entry *defobj; 2616 const Objlist_Entry *elm; 2617 def = NULL; 2618 defobj = NULL; 2619 donelist_init(&donelist); 2620 2621 /* Look first in the referencing object if linked symbolically. */ 2622 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2623 symp = symlook_obj(name, hash, refobj, ventry, flags); 2624 if (symp != NULL) { 2625 def = symp; 2626 defobj = refobj; 2627 } 2628 } 2629 2630 /* Search all objects loaded at program start up. */ 2631 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2632 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2633 &donelist); 2634 if (symp != NULL && 2635 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2636 def = symp; 2637 defobj = obj; 2638 } 2639 } 2640 2641 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2642 STAILQ_FOREACH(elm, &list_global, link) { 2643 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2644 break; 2645 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2646 flags, &donelist); 2647 if (symp != NULL && 2648 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2649 def = symp; 2650 defobj = obj; 2651 } 2652 } 2653 2654 /* Search all dlopened DAGs containing the referencing object. */ 2655 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2656 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2657 break; 2658 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2659 flags, &donelist); 2660 if (symp != NULL && 2661 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2662 def = symp; 2663 defobj = obj; 2664 } 2665 } 2666 2667 /* 2668 * Search the dynamic linker itself, and possibly resolve the 2669 * symbol from there. This is how the application links to 2670 * dynamic linker services such as dlopen. Only the values listed 2671 * in the "exports" array can be resolved from the dynamic linker. 2672 */ 2673 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2674 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2675 if (symp != NULL && is_exported(symp)) { 2676 def = symp; 2677 defobj = &obj_rtld; 2678 } 2679 } 2680 2681 if (def != NULL) 2682 *defobj_out = defobj; 2683 return def; 2684 } 2685 2686 static const Elf_Sym * 2687 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2688 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2689 DoneList *dlp) 2690 { 2691 const Elf_Sym *symp; 2692 const Elf_Sym *def; 2693 const Obj_Entry *defobj; 2694 const Objlist_Entry *elm; 2695 2696 def = NULL; 2697 defobj = NULL; 2698 STAILQ_FOREACH(elm, objlist, link) { 2699 if (donelist_check(dlp, elm->obj)) 2700 continue; 2701 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2702 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2703 def = symp; 2704 defobj = elm->obj; 2705 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2706 break; 2707 } 2708 } 2709 } 2710 if (def != NULL) 2711 *defobj_out = defobj; 2712 return def; 2713 } 2714 2715 /* 2716 * Search the symbol table of a shared object and all objects needed 2717 * by it for a symbol of the given name. Search order is 2718 * breadth-first. Returns a pointer to the symbol, or NULL if no 2719 * definition was found. 2720 */ 2721 static const Elf_Sym * 2722 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2723 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2724 DoneList *dlp) 2725 { 2726 const Elf_Sym *def, *def_w; 2727 const Needed_Entry *n; 2728 const Obj_Entry *obj, *defobj, *defobj1; 2729 2730 def = def_w = NULL; 2731 defobj = NULL; 2732 for (n = needed; n != NULL; n = n->next) { 2733 if ((obj = n->obj) == NULL || 2734 donelist_check(dlp, obj) || 2735 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2736 continue; 2737 defobj = obj; 2738 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2739 *defobj_out = defobj; 2740 return (def); 2741 } 2742 } 2743 /* 2744 * There we come when either symbol definition is not found in 2745 * directly needed objects, or found symbol is weak. 2746 */ 2747 for (n = needed; n != NULL; n = n->next) { 2748 if ((obj = n->obj) == NULL) 2749 continue; 2750 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2751 ventry, flags, dlp); 2752 if (def_w == NULL) 2753 continue; 2754 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2755 def = def_w; 2756 defobj = defobj1; 2757 } 2758 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2759 break; 2760 } 2761 if (def != NULL) 2762 *defobj_out = defobj; 2763 return (def); 2764 } 2765 2766 /* 2767 * Search the symbol table of a single shared object for a symbol of 2768 * the given name and version, if requested. Returns a pointer to the 2769 * symbol, or NULL if no definition was found. 2770 * 2771 * The symbol's hash value is passed in for efficiency reasons; that 2772 * eliminates many recomputations of the hash value. 2773 */ 2774 const Elf_Sym * 2775 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2776 const Ver_Entry *ventry, int flags) 2777 { 2778 unsigned long symnum; 2779 const Elf_Sym *vsymp; 2780 Elf_Versym verndx; 2781 int vcount; 2782 2783 if (obj->buckets == NULL) 2784 return NULL; 2785 2786 vsymp = NULL; 2787 vcount = 0; 2788 symnum = obj->buckets[hash % obj->nbuckets]; 2789 2790 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2791 const Elf_Sym *symp; 2792 const char *strp; 2793 2794 if (symnum >= obj->nchains) 2795 return NULL; /* Bad object */ 2796 2797 symp = obj->symtab + symnum; 2798 strp = obj->strtab + symp->st_name; 2799 2800 switch (ELF_ST_TYPE(symp->st_info)) { 2801 case STT_FUNC: 2802 case STT_NOTYPE: 2803 case STT_OBJECT: 2804 if (symp->st_value == 0) 2805 continue; 2806 /* fallthrough */ 2807 case STT_TLS: 2808 if (symp->st_shndx != SHN_UNDEF) 2809 break; 2810 #ifndef __mips__ 2811 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2812 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2813 break; 2814 /* fallthrough */ 2815 #endif 2816 default: 2817 continue; 2818 } 2819 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2820 continue; 2821 2822 if (ventry == NULL) { 2823 if (obj->versyms != NULL) { 2824 verndx = VER_NDX(obj->versyms[symnum]); 2825 if (verndx > obj->vernum) { 2826 _rtld_error("%s: symbol %s references wrong version %d", 2827 obj->path, obj->strtab + symnum, verndx); 2828 continue; 2829 } 2830 /* 2831 * If we are not called from dlsym (i.e. this is a normal 2832 * relocation from unversioned binary, accept the symbol 2833 * immediately if it happens to have first version after 2834 * this shared object became versioned. Otherwise, if 2835 * symbol is versioned and not hidden, remember it. If it 2836 * is the only symbol with this name exported by the 2837 * shared object, it will be returned as a match at the 2838 * end of the function. If symbol is global (verndx < 2) 2839 * accept it unconditionally. 2840 */ 2841 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2842 return symp; 2843 else if (verndx >= VER_NDX_GIVEN) { 2844 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2845 if (vsymp == NULL) 2846 vsymp = symp; 2847 vcount ++; 2848 } 2849 continue; 2850 } 2851 } 2852 return symp; 2853 } else { 2854 if (obj->versyms == NULL) { 2855 if (object_match_name(obj, ventry->name)) { 2856 _rtld_error("%s: object %s should provide version %s for " 2857 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2858 obj->strtab + symnum); 2859 continue; 2860 } 2861 } else { 2862 verndx = VER_NDX(obj->versyms[symnum]); 2863 if (verndx > obj->vernum) { 2864 _rtld_error("%s: symbol %s references wrong version %d", 2865 obj->path, obj->strtab + symnum, verndx); 2866 continue; 2867 } 2868 if (obj->vertab[verndx].hash != ventry->hash || 2869 strcmp(obj->vertab[verndx].name, ventry->name)) { 2870 /* 2871 * Version does not match. Look if this is a global symbol 2872 * and if it is not hidden. If global symbol (verndx < 2) 2873 * is available, use it. Do not return symbol if we are 2874 * called by dlvsym, because dlvsym looks for a specific 2875 * version and default one is not what dlvsym wants. 2876 */ 2877 if ((flags & SYMLOOK_DLSYM) || 2878 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2879 (verndx >= VER_NDX_GIVEN)) 2880 continue; 2881 } 2882 } 2883 return symp; 2884 } 2885 } 2886 return (vcount == 1) ? vsymp : NULL; 2887 } 2888 2889 static void 2890 trace_loaded_objects(Obj_Entry *obj) 2891 { 2892 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2893 int c; 2894 2895 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2896 main_local = ""; 2897 2898 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2899 fmt1 = "\t%o => %p (%x)\n"; 2900 2901 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2902 fmt2 = "\t%o (%x)\n"; 2903 2904 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2905 2906 for (; obj; obj = obj->next) { 2907 Needed_Entry *needed; 2908 char *name, *path; 2909 bool is_lib; 2910 2911 if (list_containers && obj->needed != NULL) 2912 printf("%s:\n", obj->path); 2913 for (needed = obj->needed; needed; needed = needed->next) { 2914 if (needed->obj != NULL) { 2915 if (needed->obj->traced && !list_containers) 2916 continue; 2917 needed->obj->traced = true; 2918 path = needed->obj->path; 2919 } else 2920 path = "not found"; 2921 2922 name = (char *)obj->strtab + needed->name; 2923 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2924 2925 fmt = is_lib ? fmt1 : fmt2; 2926 while ((c = *fmt++) != '\0') { 2927 switch (c) { 2928 default: 2929 putchar(c); 2930 continue; 2931 case '\\': 2932 switch (c = *fmt) { 2933 case '\0': 2934 continue; 2935 case 'n': 2936 putchar('\n'); 2937 break; 2938 case 't': 2939 putchar('\t'); 2940 break; 2941 } 2942 break; 2943 case '%': 2944 switch (c = *fmt) { 2945 case '\0': 2946 continue; 2947 case '%': 2948 default: 2949 putchar(c); 2950 break; 2951 case 'A': 2952 printf("%s", main_local); 2953 break; 2954 case 'a': 2955 printf("%s", obj_main->path); 2956 break; 2957 case 'o': 2958 printf("%s", name); 2959 break; 2960 #if 0 2961 case 'm': 2962 printf("%d", sodp->sod_major); 2963 break; 2964 case 'n': 2965 printf("%d", sodp->sod_minor); 2966 break; 2967 #endif 2968 case 'p': 2969 printf("%s", path); 2970 break; 2971 case 'x': 2972 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2973 break; 2974 } 2975 break; 2976 } 2977 ++fmt; 2978 } 2979 } 2980 } 2981 } 2982 2983 /* 2984 * Unload a dlopened object and its dependencies from memory and from 2985 * our data structures. It is assumed that the DAG rooted in the 2986 * object has already been unreferenced, and that the object has a 2987 * reference count of 0. 2988 */ 2989 static void 2990 unload_object(Obj_Entry *root) 2991 { 2992 Obj_Entry *obj; 2993 Obj_Entry **linkp; 2994 2995 assert(root->refcount == 0); 2996 2997 /* 2998 * Pass over the DAG removing unreferenced objects from 2999 * appropriate lists. 3000 */ 3001 unlink_object(root); 3002 3003 /* Unmap all objects that are no longer referenced. */ 3004 linkp = &obj_list->next; 3005 while ((obj = *linkp) != NULL) { 3006 if (obj->refcount == 0) { 3007 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3008 obj->path); 3009 dbg("unloading \"%s\"", obj->path); 3010 munmap(obj->mapbase, obj->mapsize); 3011 linkmap_delete(obj); 3012 *linkp = obj->next; 3013 obj_count--; 3014 obj_free(obj); 3015 } else 3016 linkp = &obj->next; 3017 } 3018 obj_tail = linkp; 3019 } 3020 3021 static void 3022 unlink_object(Obj_Entry *root) 3023 { 3024 Objlist_Entry *elm; 3025 3026 if (root->refcount == 0) { 3027 /* Remove the object from the RTLD_GLOBAL list. */ 3028 objlist_remove(&list_global, root); 3029 3030 /* Remove the object from all objects' DAG lists. */ 3031 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3032 objlist_remove(&elm->obj->dldags, root); 3033 if (elm->obj != root) 3034 unlink_object(elm->obj); 3035 } 3036 } 3037 } 3038 3039 static void 3040 ref_dag(Obj_Entry *root) 3041 { 3042 Objlist_Entry *elm; 3043 3044 STAILQ_FOREACH(elm, &root->dagmembers, link) 3045 elm->obj->refcount++; 3046 } 3047 3048 static void 3049 unref_dag(Obj_Entry *root) 3050 { 3051 Objlist_Entry *elm; 3052 3053 STAILQ_FOREACH(elm, &root->dagmembers, link) 3054 elm->obj->refcount--; 3055 } 3056 3057 /* 3058 * Common code for MD __tls_get_addr(). 3059 */ 3060 void * 3061 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3062 { 3063 Elf_Addr* dtv = *dtvp; 3064 int lockstate; 3065 3066 /* Check dtv generation in case new modules have arrived */ 3067 if (dtv[0] != tls_dtv_generation) { 3068 Elf_Addr* newdtv; 3069 int to_copy; 3070 3071 lockstate = wlock_acquire(rtld_bind_lock); 3072 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3073 to_copy = dtv[1]; 3074 if (to_copy > tls_max_index) 3075 to_copy = tls_max_index; 3076 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3077 newdtv[0] = tls_dtv_generation; 3078 newdtv[1] = tls_max_index; 3079 free(dtv); 3080 wlock_release(rtld_bind_lock, lockstate); 3081 *dtvp = newdtv; 3082 } 3083 3084 /* Dynamically allocate module TLS if necessary */ 3085 if (!dtv[index + 1]) { 3086 /* Signal safe, wlock will block out signals. */ 3087 lockstate = wlock_acquire(rtld_bind_lock); 3088 if (!dtv[index + 1]) 3089 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3090 wlock_release(rtld_bind_lock, lockstate); 3091 } 3092 return (void*) (dtv[index + 1] + offset); 3093 } 3094 3095 /* XXX not sure what variants to use for arm. */ 3096 3097 #if defined(__ia64__) || defined(__powerpc__) 3098 3099 /* 3100 * Allocate Static TLS using the Variant I method. 3101 */ 3102 void * 3103 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3104 { 3105 Obj_Entry *obj; 3106 char *tcb; 3107 Elf_Addr **tls; 3108 Elf_Addr *dtv; 3109 Elf_Addr addr; 3110 int i; 3111 3112 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3113 return (oldtcb); 3114 3115 assert(tcbsize >= TLS_TCB_SIZE); 3116 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3117 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3118 3119 if (oldtcb != NULL) { 3120 memcpy(tls, oldtcb, tls_static_space); 3121 free(oldtcb); 3122 3123 /* Adjust the DTV. */ 3124 dtv = tls[0]; 3125 for (i = 0; i < dtv[1]; i++) { 3126 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3127 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3128 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3129 } 3130 } 3131 } else { 3132 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3133 tls[0] = dtv; 3134 dtv[0] = tls_dtv_generation; 3135 dtv[1] = tls_max_index; 3136 3137 for (obj = objs; obj; obj = obj->next) { 3138 if (obj->tlsoffset) { 3139 addr = (Elf_Addr)tls + obj->tlsoffset; 3140 memset((void*) (addr + obj->tlsinitsize), 3141 0, obj->tlssize - obj->tlsinitsize); 3142 if (obj->tlsinit) 3143 memcpy((void*) addr, obj->tlsinit, 3144 obj->tlsinitsize); 3145 dtv[obj->tlsindex + 1] = addr; 3146 } 3147 } 3148 } 3149 3150 return (tcb); 3151 } 3152 3153 void 3154 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3155 { 3156 Elf_Addr *dtv; 3157 Elf_Addr tlsstart, tlsend; 3158 int dtvsize, i; 3159 3160 assert(tcbsize >= TLS_TCB_SIZE); 3161 3162 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3163 tlsend = tlsstart + tls_static_space; 3164 3165 dtv = *(Elf_Addr **)tlsstart; 3166 dtvsize = dtv[1]; 3167 for (i = 0; i < dtvsize; i++) { 3168 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3169 free((void*)dtv[i+2]); 3170 } 3171 } 3172 free(dtv); 3173 free(tcb); 3174 } 3175 3176 #endif 3177 3178 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3179 defined(__arm__) || defined(__mips__) 3180 3181 /* 3182 * Allocate Static TLS using the Variant II method. 3183 */ 3184 void * 3185 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3186 { 3187 Obj_Entry *obj; 3188 size_t size; 3189 char *tls; 3190 Elf_Addr *dtv, *olddtv; 3191 Elf_Addr segbase, oldsegbase, addr; 3192 int i; 3193 3194 size = round(tls_static_space, tcbalign); 3195 3196 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3197 tls = calloc(1, size + tcbsize); 3198 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3199 3200 segbase = (Elf_Addr)(tls + size); 3201 ((Elf_Addr*)segbase)[0] = segbase; 3202 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3203 3204 dtv[0] = tls_dtv_generation; 3205 dtv[1] = tls_max_index; 3206 3207 if (oldtls) { 3208 /* 3209 * Copy the static TLS block over whole. 3210 */ 3211 oldsegbase = (Elf_Addr) oldtls; 3212 memcpy((void *)(segbase - tls_static_space), 3213 (const void *)(oldsegbase - tls_static_space), 3214 tls_static_space); 3215 3216 /* 3217 * If any dynamic TLS blocks have been created tls_get_addr(), 3218 * move them over. 3219 */ 3220 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3221 for (i = 0; i < olddtv[1]; i++) { 3222 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3223 dtv[i+2] = olddtv[i+2]; 3224 olddtv[i+2] = 0; 3225 } 3226 } 3227 3228 /* 3229 * We assume that this block was the one we created with 3230 * allocate_initial_tls(). 3231 */ 3232 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3233 } else { 3234 for (obj = objs; obj; obj = obj->next) { 3235 if (obj->tlsoffset) { 3236 addr = segbase - obj->tlsoffset; 3237 memset((void*) (addr + obj->tlsinitsize), 3238 0, obj->tlssize - obj->tlsinitsize); 3239 if (obj->tlsinit) 3240 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3241 dtv[obj->tlsindex + 1] = addr; 3242 } 3243 } 3244 } 3245 3246 return (void*) segbase; 3247 } 3248 3249 void 3250 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3251 { 3252 size_t size; 3253 Elf_Addr* dtv; 3254 int dtvsize, i; 3255 Elf_Addr tlsstart, tlsend; 3256 3257 /* 3258 * Figure out the size of the initial TLS block so that we can 3259 * find stuff which ___tls_get_addr() allocated dynamically. 3260 */ 3261 size = round(tls_static_space, tcbalign); 3262 3263 dtv = ((Elf_Addr**)tls)[1]; 3264 dtvsize = dtv[1]; 3265 tlsend = (Elf_Addr) tls; 3266 tlsstart = tlsend - size; 3267 for (i = 0; i < dtvsize; i++) { 3268 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3269 free((void*) dtv[i+2]); 3270 } 3271 } 3272 3273 free((void*) tlsstart); 3274 free((void*) dtv); 3275 } 3276 3277 #endif 3278 3279 /* 3280 * Allocate TLS block for module with given index. 3281 */ 3282 void * 3283 allocate_module_tls(int index) 3284 { 3285 Obj_Entry* obj; 3286 char* p; 3287 3288 for (obj = obj_list; obj; obj = obj->next) { 3289 if (obj->tlsindex == index) 3290 break; 3291 } 3292 if (!obj) { 3293 _rtld_error("Can't find module with TLS index %d", index); 3294 die(); 3295 } 3296 3297 p = malloc(obj->tlssize); 3298 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3299 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3300 3301 return p; 3302 } 3303 3304 bool 3305 allocate_tls_offset(Obj_Entry *obj) 3306 { 3307 size_t off; 3308 3309 if (obj->tls_done) 3310 return true; 3311 3312 if (obj->tlssize == 0) { 3313 obj->tls_done = true; 3314 return true; 3315 } 3316 3317 if (obj->tlsindex == 1) 3318 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3319 else 3320 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3321 obj->tlssize, obj->tlsalign); 3322 3323 /* 3324 * If we have already fixed the size of the static TLS block, we 3325 * must stay within that size. When allocating the static TLS, we 3326 * leave a small amount of space spare to be used for dynamically 3327 * loading modules which use static TLS. 3328 */ 3329 if (tls_static_space) { 3330 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3331 return false; 3332 } 3333 3334 tls_last_offset = obj->tlsoffset = off; 3335 tls_last_size = obj->tlssize; 3336 obj->tls_done = true; 3337 3338 return true; 3339 } 3340 3341 void 3342 free_tls_offset(Obj_Entry *obj) 3343 { 3344 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3345 defined(__arm__) || defined(__mips__) 3346 /* 3347 * If we were the last thing to allocate out of the static TLS 3348 * block, we give our space back to the 'allocator'. This is a 3349 * simplistic workaround to allow libGL.so.1 to be loaded and 3350 * unloaded multiple times. We only handle the Variant II 3351 * mechanism for now - this really needs a proper allocator. 3352 */ 3353 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3354 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3355 tls_last_offset -= obj->tlssize; 3356 tls_last_size = 0; 3357 } 3358 #endif 3359 } 3360 3361 void * 3362 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3363 { 3364 void *ret; 3365 int lockstate; 3366 3367 lockstate = wlock_acquire(rtld_bind_lock); 3368 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3369 wlock_release(rtld_bind_lock, lockstate); 3370 return (ret); 3371 } 3372 3373 void 3374 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3375 { 3376 int lockstate; 3377 3378 lockstate = wlock_acquire(rtld_bind_lock); 3379 free_tls(tcb, tcbsize, tcbalign); 3380 wlock_release(rtld_bind_lock, lockstate); 3381 } 3382 3383 static void 3384 object_add_name(Obj_Entry *obj, const char *name) 3385 { 3386 Name_Entry *entry; 3387 size_t len; 3388 3389 len = strlen(name); 3390 entry = malloc(sizeof(Name_Entry) + len); 3391 3392 if (entry != NULL) { 3393 strcpy(entry->name, name); 3394 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3395 } 3396 } 3397 3398 static int 3399 object_match_name(const Obj_Entry *obj, const char *name) 3400 { 3401 Name_Entry *entry; 3402 3403 STAILQ_FOREACH(entry, &obj->names, link) { 3404 if (strcmp(name, entry->name) == 0) 3405 return (1); 3406 } 3407 return (0); 3408 } 3409 3410 static Obj_Entry * 3411 locate_dependency(const Obj_Entry *obj, const char *name) 3412 { 3413 const Objlist_Entry *entry; 3414 const Needed_Entry *needed; 3415 3416 STAILQ_FOREACH(entry, &list_main, link) { 3417 if (object_match_name(entry->obj, name)) 3418 return entry->obj; 3419 } 3420 3421 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3422 if (needed->obj == NULL) 3423 continue; 3424 if (object_match_name(needed->obj, name)) 3425 return needed->obj; 3426 } 3427 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3428 obj->path, name); 3429 die(); 3430 } 3431 3432 static int 3433 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3434 const Elf_Vernaux *vna) 3435 { 3436 const Elf_Verdef *vd; 3437 const char *vername; 3438 3439 vername = refobj->strtab + vna->vna_name; 3440 vd = depobj->verdef; 3441 if (vd == NULL) { 3442 _rtld_error("%s: version %s required by %s not defined", 3443 depobj->path, vername, refobj->path); 3444 return (-1); 3445 } 3446 for (;;) { 3447 if (vd->vd_version != VER_DEF_CURRENT) { 3448 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3449 depobj->path, vd->vd_version); 3450 return (-1); 3451 } 3452 if (vna->vna_hash == vd->vd_hash) { 3453 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3454 ((char *)vd + vd->vd_aux); 3455 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3456 return (0); 3457 } 3458 if (vd->vd_next == 0) 3459 break; 3460 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3461 } 3462 if (vna->vna_flags & VER_FLG_WEAK) 3463 return (0); 3464 _rtld_error("%s: version %s required by %s not found", 3465 depobj->path, vername, refobj->path); 3466 return (-1); 3467 } 3468 3469 static int 3470 rtld_verify_object_versions(Obj_Entry *obj) 3471 { 3472 const Elf_Verneed *vn; 3473 const Elf_Verdef *vd; 3474 const Elf_Verdaux *vda; 3475 const Elf_Vernaux *vna; 3476 const Obj_Entry *depobj; 3477 int maxvernum, vernum; 3478 3479 maxvernum = 0; 3480 /* 3481 * Walk over defined and required version records and figure out 3482 * max index used by any of them. Do very basic sanity checking 3483 * while there. 3484 */ 3485 vn = obj->verneed; 3486 while (vn != NULL) { 3487 if (vn->vn_version != VER_NEED_CURRENT) { 3488 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3489 obj->path, vn->vn_version); 3490 return (-1); 3491 } 3492 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3493 for (;;) { 3494 vernum = VER_NEED_IDX(vna->vna_other); 3495 if (vernum > maxvernum) 3496 maxvernum = vernum; 3497 if (vna->vna_next == 0) 3498 break; 3499 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3500 } 3501 if (vn->vn_next == 0) 3502 break; 3503 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3504 } 3505 3506 vd = obj->verdef; 3507 while (vd != NULL) { 3508 if (vd->vd_version != VER_DEF_CURRENT) { 3509 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3510 obj->path, vd->vd_version); 3511 return (-1); 3512 } 3513 vernum = VER_DEF_IDX(vd->vd_ndx); 3514 if (vernum > maxvernum) 3515 maxvernum = vernum; 3516 if (vd->vd_next == 0) 3517 break; 3518 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3519 } 3520 3521 if (maxvernum == 0) 3522 return (0); 3523 3524 /* 3525 * Store version information in array indexable by version index. 3526 * Verify that object version requirements are satisfied along the 3527 * way. 3528 */ 3529 obj->vernum = maxvernum + 1; 3530 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3531 3532 vd = obj->verdef; 3533 while (vd != NULL) { 3534 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3535 vernum = VER_DEF_IDX(vd->vd_ndx); 3536 assert(vernum <= maxvernum); 3537 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3538 obj->vertab[vernum].hash = vd->vd_hash; 3539 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3540 obj->vertab[vernum].file = NULL; 3541 obj->vertab[vernum].flags = 0; 3542 } 3543 if (vd->vd_next == 0) 3544 break; 3545 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3546 } 3547 3548 vn = obj->verneed; 3549 while (vn != NULL) { 3550 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3551 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3552 for (;;) { 3553 if (check_object_provided_version(obj, depobj, vna)) 3554 return (-1); 3555 vernum = VER_NEED_IDX(vna->vna_other); 3556 assert(vernum <= maxvernum); 3557 obj->vertab[vernum].hash = vna->vna_hash; 3558 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3559 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3560 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3561 VER_INFO_HIDDEN : 0; 3562 if (vna->vna_next == 0) 3563 break; 3564 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3565 } 3566 if (vn->vn_next == 0) 3567 break; 3568 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3569 } 3570 return 0; 3571 } 3572 3573 static int 3574 rtld_verify_versions(const Objlist *objlist) 3575 { 3576 Objlist_Entry *entry; 3577 int rc; 3578 3579 rc = 0; 3580 STAILQ_FOREACH(entry, objlist, link) { 3581 /* 3582 * Skip dummy objects or objects that have their version requirements 3583 * already checked. 3584 */ 3585 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3586 continue; 3587 if (rtld_verify_object_versions(entry->obj) == -1) { 3588 rc = -1; 3589 if (ld_tracing == NULL) 3590 break; 3591 } 3592 } 3593 if (rc == 0 || ld_tracing != NULL) 3594 rc = rtld_verify_object_versions(&obj_rtld); 3595 return rc; 3596 } 3597 3598 const Ver_Entry * 3599 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3600 { 3601 Elf_Versym vernum; 3602 3603 if (obj->vertab) { 3604 vernum = VER_NDX(obj->versyms[symnum]); 3605 if (vernum >= obj->vernum) { 3606 _rtld_error("%s: symbol %s has wrong verneed value %d", 3607 obj->path, obj->strtab + symnum, vernum); 3608 } else if (obj->vertab[vernum].hash != 0) { 3609 return &obj->vertab[vernum]; 3610 } 3611 } 3612 return NULL; 3613 } 3614