1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/uio.h> 44 #include <sys/utsname.h> 45 #include <sys/ktrace.h> 46 47 #include <dlfcn.h> 48 #include <err.h> 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <stdarg.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #include "debug.h" 58 #include "rtld.h" 59 #include "libmap.h" 60 #include "rtld_tls.h" 61 62 #ifndef COMPAT_32BIT 63 #define PATH_RTLD "/libexec/ld-elf.so.1" 64 #else 65 #define PATH_RTLD "/libexec/ld-elf32.so.1" 66 #endif 67 68 /* Types. */ 69 typedef void (*func_ptr_type)(); 70 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 71 72 /* 73 * This structure provides a reentrant way to keep a list of objects and 74 * check which ones have already been processed in some way. 75 */ 76 typedef struct Struct_DoneList { 77 const Obj_Entry **objs; /* Array of object pointers */ 78 unsigned int num_alloc; /* Allocated size of the array */ 79 unsigned int num_used; /* Number of array slots used */ 80 } DoneList; 81 82 /* 83 * Function declarations. 84 */ 85 static const char *basename(const char *); 86 static void die(void) __dead2; 87 static void digest_dynamic(Obj_Entry *, int); 88 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 89 static Obj_Entry *dlcheck(void *); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *); 97 static const char *gethints(void); 98 static void init_dag(Obj_Entry *); 99 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 100 static void init_rtld(caddr_t); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static bool is_exported(const Elf_Sym *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static int load_needed_objects(Obj_Entry *); 107 static int load_preload_objects(void); 108 static Obj_Entry *load_object(const char *, const Obj_Entry *); 109 static Obj_Entry *obj_from_addr(const void *); 110 static void objlist_call_fini(Objlist *, int *lockstate); 111 static void objlist_call_init(Objlist *, int *lockstate); 112 static void objlist_clear(Objlist *); 113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114 static void objlist_init(Objlist *); 115 static void objlist_push_head(Objlist *, Obj_Entry *); 116 static void objlist_push_tail(Objlist *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static void objlist_remove_unref(Objlist *); 119 static void *path_enumerate(const char *, path_enum_proc, void *); 120 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 121 static int rtld_dirname(const char *, char *); 122 static int rtld_dirname_abs(const char *, char *); 123 static void rtld_exit(void); 124 static char *search_library_path(const char *, const char *); 125 static const void **get_program_var_addr(const char *); 126 static void set_program_var(const char *, const void *); 127 static const Elf_Sym *symlook_default(const char *, unsigned long, 128 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 129 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 130 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 131 static const Elf_Sym *symlook_needed(const char *, unsigned long, 132 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 133 int, DoneList *); 134 static void trace_loaded_objects(Obj_Entry *); 135 static void unlink_object(Obj_Entry *); 136 static void unload_object(Obj_Entry *); 137 static void unref_dag(Obj_Entry *); 138 static void ref_dag(Obj_Entry *); 139 static int origin_subst_one(char **res, const char *real, const char *kw, 140 const char *subst, char *may_free); 141 static char *origin_subst(const char *real, const char *origin_path); 142 static int rtld_verify_versions(const Objlist *); 143 static int rtld_verify_object_versions(Obj_Entry *); 144 static void object_add_name(Obj_Entry *, const char *); 145 static int object_match_name(const Obj_Entry *, const char *); 146 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 147 148 void r_debug_state(struct r_debug *, struct link_map *); 149 150 /* 151 * Data declarations. 152 */ 153 static char *error_message; /* Message for dlerror(), or NULL */ 154 struct r_debug r_debug; /* for GDB; */ 155 static bool libmap_disable; /* Disable libmap */ 156 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 157 static bool trust; /* False for setuid and setgid programs */ 158 static bool dangerous_ld_env; /* True if environment variables have been 159 used to affect the libraries loaded */ 160 static char *ld_bind_now; /* Environment variable for immediate binding */ 161 static char *ld_debug; /* Environment variable for debugging */ 162 static char *ld_library_path; /* Environment variable for search path */ 163 static char *ld_preload; /* Environment variable for libraries to 164 load first */ 165 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 166 static char *ld_tracing; /* Called from ldd to print libs */ 167 static char *ld_utrace; /* Use utrace() to log events. */ 168 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 169 static Obj_Entry **obj_tail; /* Link field of last object in list */ 170 static Obj_Entry *obj_main; /* The main program shared object */ 171 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 172 static unsigned int obj_count; /* Number of objects in obj_list */ 173 static unsigned int obj_loads; /* Number of objects in obj_list */ 174 175 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 176 STAILQ_HEAD_INITIALIZER(list_global); 177 static Objlist list_main = /* Objects loaded at program startup */ 178 STAILQ_HEAD_INITIALIZER(list_main); 179 static Objlist list_fini = /* Objects needing fini() calls */ 180 STAILQ_HEAD_INITIALIZER(list_fini); 181 182 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 183 184 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 185 186 extern Elf_Dyn _DYNAMIC; 187 #pragma weak _DYNAMIC 188 #ifndef RTLD_IS_DYNAMIC 189 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 190 #endif 191 192 /* 193 * These are the functions the dynamic linker exports to application 194 * programs. They are the only symbols the dynamic linker is willing 195 * to export from itself. 196 */ 197 static func_ptr_type exports[] = { 198 (func_ptr_type) &_rtld_error, 199 (func_ptr_type) &dlclose, 200 (func_ptr_type) &dlerror, 201 (func_ptr_type) &dlopen, 202 (func_ptr_type) &dlsym, 203 (func_ptr_type) &dlfunc, 204 (func_ptr_type) &dlvsym, 205 (func_ptr_type) &dladdr, 206 (func_ptr_type) &dllockinit, 207 (func_ptr_type) &dlinfo, 208 (func_ptr_type) &_rtld_thread_init, 209 #ifdef __i386__ 210 (func_ptr_type) &___tls_get_addr, 211 #endif 212 (func_ptr_type) &__tls_get_addr, 213 (func_ptr_type) &_rtld_allocate_tls, 214 (func_ptr_type) &_rtld_free_tls, 215 (func_ptr_type) &dl_iterate_phdr, 216 (func_ptr_type) &_rtld_atfork_pre, 217 (func_ptr_type) &_rtld_atfork_post, 218 NULL 219 }; 220 221 /* 222 * Global declarations normally provided by crt1. The dynamic linker is 223 * not built with crt1, so we have to provide them ourselves. 224 */ 225 char *__progname; 226 char **environ; 227 228 /* 229 * Globals to control TLS allocation. 230 */ 231 size_t tls_last_offset; /* Static TLS offset of last module */ 232 size_t tls_last_size; /* Static TLS size of last module */ 233 size_t tls_static_space; /* Static TLS space allocated */ 234 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 235 int tls_max_index = 1; /* Largest module index allocated */ 236 237 /* 238 * Fill in a DoneList with an allocation large enough to hold all of 239 * the currently-loaded objects. Keep this as a macro since it calls 240 * alloca and we want that to occur within the scope of the caller. 241 */ 242 #define donelist_init(dlp) \ 243 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 244 assert((dlp)->objs != NULL), \ 245 (dlp)->num_alloc = obj_count, \ 246 (dlp)->num_used = 0) 247 248 #define UTRACE_DLOPEN_START 1 249 #define UTRACE_DLOPEN_STOP 2 250 #define UTRACE_DLCLOSE_START 3 251 #define UTRACE_DLCLOSE_STOP 4 252 #define UTRACE_LOAD_OBJECT 5 253 #define UTRACE_UNLOAD_OBJECT 6 254 #define UTRACE_ADD_RUNDEP 7 255 #define UTRACE_PRELOAD_FINISHED 8 256 #define UTRACE_INIT_CALL 9 257 #define UTRACE_FINI_CALL 10 258 259 struct utrace_rtld { 260 char sig[4]; /* 'RTLD' */ 261 int event; 262 void *handle; 263 void *mapbase; /* Used for 'parent' and 'init/fini' */ 264 size_t mapsize; 265 int refcnt; /* Used for 'mode' */ 266 char name[MAXPATHLEN]; 267 }; 268 269 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 270 if (ld_utrace != NULL) \ 271 ld_utrace_log(e, h, mb, ms, r, n); \ 272 } while (0) 273 274 static void 275 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 276 int refcnt, const char *name) 277 { 278 struct utrace_rtld ut; 279 280 ut.sig[0] = 'R'; 281 ut.sig[1] = 'T'; 282 ut.sig[2] = 'L'; 283 ut.sig[3] = 'D'; 284 ut.event = event; 285 ut.handle = handle; 286 ut.mapbase = mapbase; 287 ut.mapsize = mapsize; 288 ut.refcnt = refcnt; 289 bzero(ut.name, sizeof(ut.name)); 290 if (name) 291 strlcpy(ut.name, name, sizeof(ut.name)); 292 utrace(&ut, sizeof(ut)); 293 } 294 295 /* 296 * Main entry point for dynamic linking. The first argument is the 297 * stack pointer. The stack is expected to be laid out as described 298 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 299 * Specifically, the stack pointer points to a word containing 300 * ARGC. Following that in the stack is a null-terminated sequence 301 * of pointers to argument strings. Then comes a null-terminated 302 * sequence of pointers to environment strings. Finally, there is a 303 * sequence of "auxiliary vector" entries. 304 * 305 * The second argument points to a place to store the dynamic linker's 306 * exit procedure pointer and the third to a place to store the main 307 * program's object. 308 * 309 * The return value is the main program's entry point. 310 */ 311 func_ptr_type 312 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 313 { 314 Elf_Auxinfo *aux_info[AT_COUNT]; 315 int i; 316 int argc; 317 char **argv; 318 char **env; 319 Elf_Auxinfo *aux; 320 Elf_Auxinfo *auxp; 321 const char *argv0; 322 Objlist_Entry *entry; 323 Obj_Entry *obj; 324 Obj_Entry **preload_tail; 325 Objlist initlist; 326 int lockstate; 327 328 /* 329 * On entry, the dynamic linker itself has not been relocated yet. 330 * Be very careful not to reference any global data until after 331 * init_rtld has returned. It is OK to reference file-scope statics 332 * and string constants, and to call static and global functions. 333 */ 334 335 /* Find the auxiliary vector on the stack. */ 336 argc = *sp++; 337 argv = (char **) sp; 338 sp += argc + 1; /* Skip over arguments and NULL terminator */ 339 env = (char **) sp; 340 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 341 ; 342 aux = (Elf_Auxinfo *) sp; 343 344 /* Digest the auxiliary vector. */ 345 for (i = 0; i < AT_COUNT; i++) 346 aux_info[i] = NULL; 347 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 348 if (auxp->a_type < AT_COUNT) 349 aux_info[auxp->a_type] = auxp; 350 } 351 352 /* Initialize and relocate ourselves. */ 353 assert(aux_info[AT_BASE] != NULL); 354 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 355 356 __progname = obj_rtld.path; 357 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 358 environ = env; 359 360 trust = !issetugid(); 361 362 ld_bind_now = getenv(LD_ "BIND_NOW"); 363 /* 364 * If the process is tainted, then we un-set the dangerous environment 365 * variables. The process will be marked as tainted until setuid(2) 366 * is called. If any child process calls setuid(2) we do not want any 367 * future processes to honor the potentially un-safe variables. 368 */ 369 if (!trust) { 370 unsetenv(LD_ "PRELOAD"); 371 unsetenv(LD_ "LIBMAP"); 372 unsetenv(LD_ "LIBRARY_PATH"); 373 unsetenv(LD_ "LIBMAP_DISABLE"); 374 unsetenv(LD_ "DEBUG"); 375 unsetenv(LD_ "ELF_HINTS_PATH"); 376 } 377 ld_debug = getenv(LD_ "DEBUG"); 378 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 379 libmap_override = getenv(LD_ "LIBMAP"); 380 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 381 ld_preload = getenv(LD_ "PRELOAD"); 382 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 383 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 384 (ld_library_path != NULL) || (ld_preload != NULL) || 385 (ld_elf_hints_path != NULL); 386 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 387 ld_utrace = getenv(LD_ "UTRACE"); 388 389 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 390 ld_elf_hints_path = _PATH_ELF_HINTS; 391 392 if (ld_debug != NULL && *ld_debug != '\0') 393 debug = 1; 394 dbg("%s is initialized, base address = %p", __progname, 395 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 396 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 397 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 398 399 /* 400 * Load the main program, or process its program header if it is 401 * already loaded. 402 */ 403 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 404 int fd = aux_info[AT_EXECFD]->a_un.a_val; 405 dbg("loading main program"); 406 obj_main = map_object(fd, argv0, NULL); 407 close(fd); 408 if (obj_main == NULL) 409 die(); 410 } else { /* Main program already loaded. */ 411 const Elf_Phdr *phdr; 412 int phnum; 413 caddr_t entry; 414 415 dbg("processing main program's program header"); 416 assert(aux_info[AT_PHDR] != NULL); 417 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 418 assert(aux_info[AT_PHNUM] != NULL); 419 phnum = aux_info[AT_PHNUM]->a_un.a_val; 420 assert(aux_info[AT_PHENT] != NULL); 421 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 422 assert(aux_info[AT_ENTRY] != NULL); 423 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 424 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 425 die(); 426 } 427 428 if (aux_info[AT_EXECPATH] != 0) { 429 char *kexecpath; 430 char buf[MAXPATHLEN]; 431 432 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 433 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 434 if (kexecpath[0] == '/') 435 obj_main->path = kexecpath; 436 else if (getcwd(buf, sizeof(buf)) == NULL || 437 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 438 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 439 obj_main->path = xstrdup(argv0); 440 else 441 obj_main->path = xstrdup(buf); 442 } else { 443 dbg("No AT_EXECPATH"); 444 obj_main->path = xstrdup(argv0); 445 } 446 dbg("obj_main path %s", obj_main->path); 447 obj_main->mainprog = true; 448 449 /* 450 * Get the actual dynamic linker pathname from the executable if 451 * possible. (It should always be possible.) That ensures that 452 * gdb will find the right dynamic linker even if a non-standard 453 * one is being used. 454 */ 455 if (obj_main->interp != NULL && 456 strcmp(obj_main->interp, obj_rtld.path) != 0) { 457 free(obj_rtld.path); 458 obj_rtld.path = xstrdup(obj_main->interp); 459 __progname = obj_rtld.path; 460 } 461 462 digest_dynamic(obj_main, 0); 463 464 linkmap_add(obj_main); 465 linkmap_add(&obj_rtld); 466 467 /* Link the main program into the list of objects. */ 468 *obj_tail = obj_main; 469 obj_tail = &obj_main->next; 470 obj_count++; 471 obj_loads++; 472 /* Make sure we don't call the main program's init and fini functions. */ 473 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 474 475 /* Initialize a fake symbol for resolving undefined weak references. */ 476 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 477 sym_zero.st_shndx = SHN_UNDEF; 478 479 if (!libmap_disable) 480 libmap_disable = (bool)lm_init(libmap_override); 481 482 dbg("loading LD_PRELOAD libraries"); 483 if (load_preload_objects() == -1) 484 die(); 485 preload_tail = obj_tail; 486 487 dbg("loading needed objects"); 488 if (load_needed_objects(obj_main) == -1) 489 die(); 490 491 /* Make a list of all objects loaded at startup. */ 492 for (obj = obj_list; obj != NULL; obj = obj->next) { 493 objlist_push_tail(&list_main, obj); 494 obj->refcount++; 495 } 496 497 dbg("checking for required versions"); 498 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 499 die(); 500 501 if (ld_tracing) { /* We're done */ 502 trace_loaded_objects(obj_main); 503 exit(0); 504 } 505 506 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 507 dump_relocations(obj_main); 508 exit (0); 509 } 510 511 /* setup TLS for main thread */ 512 dbg("initializing initial thread local storage"); 513 STAILQ_FOREACH(entry, &list_main, link) { 514 /* 515 * Allocate all the initial objects out of the static TLS 516 * block even if they didn't ask for it. 517 */ 518 allocate_tls_offset(entry->obj); 519 } 520 allocate_initial_tls(obj_list); 521 522 if (relocate_objects(obj_main, 523 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 524 die(); 525 526 dbg("doing copy relocations"); 527 if (do_copy_relocations(obj_main) == -1) 528 die(); 529 530 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 531 dump_relocations(obj_main); 532 exit (0); 533 } 534 535 dbg("initializing key program variables"); 536 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 537 set_program_var("environ", env); 538 539 dbg("initializing thread locks"); 540 lockdflt_init(); 541 542 /* Make a list of init functions to call. */ 543 objlist_init(&initlist); 544 initlist_add_objects(obj_list, preload_tail, &initlist); 545 546 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 547 548 lockstate = wlock_acquire(rtld_bind_lock); 549 objlist_call_init(&initlist, &lockstate); 550 objlist_clear(&initlist); 551 wlock_release(rtld_bind_lock, lockstate); 552 553 dbg("transferring control to program entry point = %p", obj_main->entry); 554 555 /* Return the exit procedure and the program entry point. */ 556 *exit_proc = rtld_exit; 557 *objp = obj_main; 558 return (func_ptr_type) obj_main->entry; 559 } 560 561 Elf_Addr 562 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 563 { 564 const Elf_Rel *rel; 565 const Elf_Sym *def; 566 const Obj_Entry *defobj; 567 Elf_Addr *where; 568 Elf_Addr target; 569 int lockstate; 570 571 lockstate = rlock_acquire(rtld_bind_lock); 572 if (obj->pltrel) 573 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 574 else 575 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 576 577 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 578 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 579 if (def == NULL) 580 die(); 581 582 target = (Elf_Addr)(defobj->relocbase + def->st_value); 583 584 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 585 defobj->strtab + def->st_name, basename(obj->path), 586 (void *)target, basename(defobj->path)); 587 588 /* 589 * Write the new contents for the jmpslot. Note that depending on 590 * architecture, the value which we need to return back to the 591 * lazy binding trampoline may or may not be the target 592 * address. The value returned from reloc_jmpslot() is the value 593 * that the trampoline needs. 594 */ 595 target = reloc_jmpslot(where, target, defobj, obj, rel); 596 rlock_release(rtld_bind_lock, lockstate); 597 return target; 598 } 599 600 /* 601 * Error reporting function. Use it like printf. If formats the message 602 * into a buffer, and sets things up so that the next call to dlerror() 603 * will return the message. 604 */ 605 void 606 _rtld_error(const char *fmt, ...) 607 { 608 static char buf[512]; 609 va_list ap; 610 611 va_start(ap, fmt); 612 vsnprintf(buf, sizeof buf, fmt, ap); 613 error_message = buf; 614 va_end(ap); 615 } 616 617 /* 618 * Return a dynamically-allocated copy of the current error message, if any. 619 */ 620 static char * 621 errmsg_save(void) 622 { 623 return error_message == NULL ? NULL : xstrdup(error_message); 624 } 625 626 /* 627 * Restore the current error message from a copy which was previously saved 628 * by errmsg_save(). The copy is freed. 629 */ 630 static void 631 errmsg_restore(char *saved_msg) 632 { 633 if (saved_msg == NULL) 634 error_message = NULL; 635 else { 636 _rtld_error("%s", saved_msg); 637 free(saved_msg); 638 } 639 } 640 641 static const char * 642 basename(const char *name) 643 { 644 const char *p = strrchr(name, '/'); 645 return p != NULL ? p + 1 : name; 646 } 647 648 static struct utsname uts; 649 650 static int 651 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 652 char *may_free) 653 { 654 const char *p, *p1; 655 char *res1; 656 int subst_len; 657 int kw_len; 658 659 res1 = *res = NULL; 660 p = real; 661 subst_len = kw_len = 0; 662 for (;;) { 663 p1 = strstr(p, kw); 664 if (p1 != NULL) { 665 if (subst_len == 0) { 666 subst_len = strlen(subst); 667 kw_len = strlen(kw); 668 } 669 if (*res == NULL) { 670 *res = xmalloc(PATH_MAX); 671 res1 = *res; 672 } 673 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 674 _rtld_error("Substitution of %s in %s cannot be performed", 675 kw, real); 676 if (may_free != NULL) 677 free(may_free); 678 free(res); 679 return (false); 680 } 681 memcpy(res1, p, p1 - p); 682 res1 += p1 - p; 683 memcpy(res1, subst, subst_len); 684 res1 += subst_len; 685 p = p1 + kw_len; 686 } else { 687 if (*res == NULL) { 688 if (may_free != NULL) 689 *res = may_free; 690 else 691 *res = xstrdup(real); 692 return (true); 693 } 694 *res1 = '\0'; 695 if (may_free != NULL) 696 free(may_free); 697 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 698 free(res); 699 return (false); 700 } 701 return (true); 702 } 703 } 704 } 705 706 static char * 707 origin_subst(const char *real, const char *origin_path) 708 { 709 char *res1, *res2, *res3, *res4; 710 711 if (uts.sysname[0] == '\0') { 712 if (uname(&uts) != 0) { 713 _rtld_error("utsname failed: %d", errno); 714 return (NULL); 715 } 716 } 717 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 718 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 719 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 720 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 721 return (NULL); 722 return (res4); 723 } 724 725 static void 726 die(void) 727 { 728 const char *msg = dlerror(); 729 730 if (msg == NULL) 731 msg = "Fatal error"; 732 errx(1, "%s", msg); 733 } 734 735 /* 736 * Process a shared object's DYNAMIC section, and save the important 737 * information in its Obj_Entry structure. 738 */ 739 static void 740 digest_dynamic(Obj_Entry *obj, int early) 741 { 742 const Elf_Dyn *dynp; 743 Needed_Entry **needed_tail = &obj->needed; 744 const Elf_Dyn *dyn_rpath = NULL; 745 const Elf_Dyn *dyn_soname = NULL; 746 int plttype = DT_REL; 747 748 obj->bind_now = false; 749 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 750 switch (dynp->d_tag) { 751 752 case DT_REL: 753 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 754 break; 755 756 case DT_RELSZ: 757 obj->relsize = dynp->d_un.d_val; 758 break; 759 760 case DT_RELENT: 761 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 762 break; 763 764 case DT_JMPREL: 765 obj->pltrel = (const Elf_Rel *) 766 (obj->relocbase + dynp->d_un.d_ptr); 767 break; 768 769 case DT_PLTRELSZ: 770 obj->pltrelsize = dynp->d_un.d_val; 771 break; 772 773 case DT_RELA: 774 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 775 break; 776 777 case DT_RELASZ: 778 obj->relasize = dynp->d_un.d_val; 779 break; 780 781 case DT_RELAENT: 782 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 783 break; 784 785 case DT_PLTREL: 786 plttype = dynp->d_un.d_val; 787 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 788 break; 789 790 case DT_SYMTAB: 791 obj->symtab = (const Elf_Sym *) 792 (obj->relocbase + dynp->d_un.d_ptr); 793 break; 794 795 case DT_SYMENT: 796 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 797 break; 798 799 case DT_STRTAB: 800 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 801 break; 802 803 case DT_STRSZ: 804 obj->strsize = dynp->d_un.d_val; 805 break; 806 807 case DT_VERNEED: 808 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 809 dynp->d_un.d_val); 810 break; 811 812 case DT_VERNEEDNUM: 813 obj->verneednum = dynp->d_un.d_val; 814 break; 815 816 case DT_VERDEF: 817 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 818 dynp->d_un.d_val); 819 break; 820 821 case DT_VERDEFNUM: 822 obj->verdefnum = dynp->d_un.d_val; 823 break; 824 825 case DT_VERSYM: 826 obj->versyms = (const Elf_Versym *)(obj->relocbase + 827 dynp->d_un.d_val); 828 break; 829 830 case DT_HASH: 831 { 832 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 833 (obj->relocbase + dynp->d_un.d_ptr); 834 obj->nbuckets = hashtab[0]; 835 obj->nchains = hashtab[1]; 836 obj->buckets = hashtab + 2; 837 obj->chains = obj->buckets + obj->nbuckets; 838 } 839 break; 840 841 case DT_NEEDED: 842 if (!obj->rtld) { 843 Needed_Entry *nep = NEW(Needed_Entry); 844 nep->name = dynp->d_un.d_val; 845 nep->obj = NULL; 846 nep->next = NULL; 847 848 *needed_tail = nep; 849 needed_tail = &nep->next; 850 } 851 break; 852 853 case DT_PLTGOT: 854 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 855 break; 856 857 case DT_TEXTREL: 858 obj->textrel = true; 859 break; 860 861 case DT_SYMBOLIC: 862 obj->symbolic = true; 863 break; 864 865 case DT_RPATH: 866 case DT_RUNPATH: /* XXX: process separately */ 867 /* 868 * We have to wait until later to process this, because we 869 * might not have gotten the address of the string table yet. 870 */ 871 dyn_rpath = dynp; 872 break; 873 874 case DT_SONAME: 875 dyn_soname = dynp; 876 break; 877 878 case DT_INIT: 879 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 880 break; 881 882 case DT_FINI: 883 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 884 break; 885 886 /* 887 * Don't process DT_DEBUG on MIPS as the dynamic section 888 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 889 */ 890 891 #ifndef __mips__ 892 case DT_DEBUG: 893 /* XXX - not implemented yet */ 894 if (!early) 895 dbg("Filling in DT_DEBUG entry"); 896 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 897 break; 898 #endif 899 900 case DT_FLAGS: 901 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 902 obj->z_origin = true; 903 if (dynp->d_un.d_val & DF_SYMBOLIC) 904 obj->symbolic = true; 905 if (dynp->d_un.d_val & DF_TEXTREL) 906 obj->textrel = true; 907 if (dynp->d_un.d_val & DF_BIND_NOW) 908 obj->bind_now = true; 909 if (dynp->d_un.d_val & DF_STATIC_TLS) 910 ; 911 break; 912 #ifdef __mips__ 913 case DT_MIPS_LOCAL_GOTNO: 914 obj->local_gotno = dynp->d_un.d_val; 915 break; 916 917 case DT_MIPS_SYMTABNO: 918 obj->symtabno = dynp->d_un.d_val; 919 break; 920 921 case DT_MIPS_GOTSYM: 922 obj->gotsym = dynp->d_un.d_val; 923 break; 924 925 case DT_MIPS_RLD_MAP: 926 #ifdef notyet 927 if (!early) 928 dbg("Filling in DT_DEBUG entry"); 929 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 930 #endif 931 break; 932 #endif 933 934 case DT_FLAGS_1: 935 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 936 obj->z_origin = true; 937 if (dynp->d_un.d_val & DF_1_GLOBAL) 938 /* XXX */; 939 if (dynp->d_un.d_val & DF_1_BIND_NOW) 940 obj->bind_now = true; 941 if (dynp->d_un.d_val & DF_1_NODELETE) 942 obj->z_nodelete = true; 943 break; 944 945 default: 946 if (!early) { 947 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 948 (long)dynp->d_tag); 949 } 950 break; 951 } 952 } 953 954 obj->traced = false; 955 956 if (plttype == DT_RELA) { 957 obj->pltrela = (const Elf_Rela *) obj->pltrel; 958 obj->pltrel = NULL; 959 obj->pltrelasize = obj->pltrelsize; 960 obj->pltrelsize = 0; 961 } 962 963 if (obj->z_origin && obj->origin_path == NULL) { 964 obj->origin_path = xmalloc(PATH_MAX); 965 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 966 die(); 967 } 968 969 if (dyn_rpath != NULL) { 970 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 971 if (obj->z_origin) 972 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 973 } 974 975 if (dyn_soname != NULL) 976 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 977 } 978 979 /* 980 * Process a shared object's program header. This is used only for the 981 * main program, when the kernel has already loaded the main program 982 * into memory before calling the dynamic linker. It creates and 983 * returns an Obj_Entry structure. 984 */ 985 static Obj_Entry * 986 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 987 { 988 Obj_Entry *obj; 989 const Elf_Phdr *phlimit = phdr + phnum; 990 const Elf_Phdr *ph; 991 int nsegs = 0; 992 993 obj = obj_new(); 994 for (ph = phdr; ph < phlimit; ph++) { 995 switch (ph->p_type) { 996 997 case PT_PHDR: 998 if ((const Elf_Phdr *)ph->p_vaddr != phdr) { 999 _rtld_error("%s: invalid PT_PHDR", path); 1000 return NULL; 1001 } 1002 obj->phdr = (const Elf_Phdr *) ph->p_vaddr; 1003 obj->phsize = ph->p_memsz; 1004 break; 1005 1006 case PT_INTERP: 1007 obj->interp = (const char *) ph->p_vaddr; 1008 break; 1009 1010 case PT_LOAD: 1011 if (nsegs == 0) { /* First load segment */ 1012 obj->vaddrbase = trunc_page(ph->p_vaddr); 1013 obj->mapbase = (caddr_t) obj->vaddrbase; 1014 obj->relocbase = obj->mapbase - obj->vaddrbase; 1015 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1016 obj->vaddrbase; 1017 } else { /* Last load segment */ 1018 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1019 obj->vaddrbase; 1020 } 1021 nsegs++; 1022 break; 1023 1024 case PT_DYNAMIC: 1025 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; 1026 break; 1027 1028 case PT_TLS: 1029 obj->tlsindex = 1; 1030 obj->tlssize = ph->p_memsz; 1031 obj->tlsalign = ph->p_align; 1032 obj->tlsinitsize = ph->p_filesz; 1033 obj->tlsinit = (void*) ph->p_vaddr; 1034 break; 1035 } 1036 } 1037 if (nsegs < 1) { 1038 _rtld_error("%s: too few PT_LOAD segments", path); 1039 return NULL; 1040 } 1041 1042 obj->entry = entry; 1043 return obj; 1044 } 1045 1046 static Obj_Entry * 1047 dlcheck(void *handle) 1048 { 1049 Obj_Entry *obj; 1050 1051 for (obj = obj_list; obj != NULL; obj = obj->next) 1052 if (obj == (Obj_Entry *) handle) 1053 break; 1054 1055 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1056 _rtld_error("Invalid shared object handle %p", handle); 1057 return NULL; 1058 } 1059 return obj; 1060 } 1061 1062 /* 1063 * If the given object is already in the donelist, return true. Otherwise 1064 * add the object to the list and return false. 1065 */ 1066 static bool 1067 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1068 { 1069 unsigned int i; 1070 1071 for (i = 0; i < dlp->num_used; i++) 1072 if (dlp->objs[i] == obj) 1073 return true; 1074 /* 1075 * Our donelist allocation should always be sufficient. But if 1076 * our threads locking isn't working properly, more shared objects 1077 * could have been loaded since we allocated the list. That should 1078 * never happen, but we'll handle it properly just in case it does. 1079 */ 1080 if (dlp->num_used < dlp->num_alloc) 1081 dlp->objs[dlp->num_used++] = obj; 1082 return false; 1083 } 1084 1085 /* 1086 * Hash function for symbol table lookup. Don't even think about changing 1087 * this. It is specified by the System V ABI. 1088 */ 1089 unsigned long 1090 elf_hash(const char *name) 1091 { 1092 const unsigned char *p = (const unsigned char *) name; 1093 unsigned long h = 0; 1094 unsigned long g; 1095 1096 while (*p != '\0') { 1097 h = (h << 4) + *p++; 1098 if ((g = h & 0xf0000000) != 0) 1099 h ^= g >> 24; 1100 h &= ~g; 1101 } 1102 return h; 1103 } 1104 1105 /* 1106 * Find the library with the given name, and return its full pathname. 1107 * The returned string is dynamically allocated. Generates an error 1108 * message and returns NULL if the library cannot be found. 1109 * 1110 * If the second argument is non-NULL, then it refers to an already- 1111 * loaded shared object, whose library search path will be searched. 1112 * 1113 * The search order is: 1114 * LD_LIBRARY_PATH 1115 * rpath in the referencing file 1116 * ldconfig hints 1117 * /lib:/usr/lib 1118 */ 1119 static char * 1120 find_library(const char *xname, const Obj_Entry *refobj) 1121 { 1122 char *pathname; 1123 char *name; 1124 1125 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1126 if (xname[0] != '/' && !trust) { 1127 _rtld_error("Absolute pathname required for shared object \"%s\"", 1128 xname); 1129 return NULL; 1130 } 1131 if (refobj != NULL && refobj->z_origin) 1132 return origin_subst(xname, refobj->origin_path); 1133 else 1134 return xstrdup(xname); 1135 } 1136 1137 if (libmap_disable || (refobj == NULL) || 1138 (name = lm_find(refobj->path, xname)) == NULL) 1139 name = (char *)xname; 1140 1141 dbg(" Searching for \"%s\"", name); 1142 1143 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1144 (refobj != NULL && 1145 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1146 (pathname = search_library_path(name, gethints())) != NULL || 1147 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1148 return pathname; 1149 1150 if(refobj != NULL && refobj->path != NULL) { 1151 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1152 name, basename(refobj->path)); 1153 } else { 1154 _rtld_error("Shared object \"%s\" not found", name); 1155 } 1156 return NULL; 1157 } 1158 1159 /* 1160 * Given a symbol number in a referencing object, find the corresponding 1161 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1162 * no definition was found. Returns a pointer to the Obj_Entry of the 1163 * defining object via the reference parameter DEFOBJ_OUT. 1164 */ 1165 const Elf_Sym * 1166 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1167 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1168 { 1169 const Elf_Sym *ref; 1170 const Elf_Sym *def; 1171 const Obj_Entry *defobj; 1172 const Ver_Entry *ventry; 1173 const char *name; 1174 unsigned long hash; 1175 1176 /* 1177 * If we have already found this symbol, get the information from 1178 * the cache. 1179 */ 1180 if (symnum >= refobj->nchains) 1181 return NULL; /* Bad object */ 1182 if (cache != NULL && cache[symnum].sym != NULL) { 1183 *defobj_out = cache[symnum].obj; 1184 return cache[symnum].sym; 1185 } 1186 1187 ref = refobj->symtab + symnum; 1188 name = refobj->strtab + ref->st_name; 1189 defobj = NULL; 1190 1191 /* 1192 * We don't have to do a full scale lookup if the symbol is local. 1193 * We know it will bind to the instance in this load module; to 1194 * which we already have a pointer (ie ref). By not doing a lookup, 1195 * we not only improve performance, but it also avoids unresolvable 1196 * symbols when local symbols are not in the hash table. This has 1197 * been seen with the ia64 toolchain. 1198 */ 1199 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1200 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1201 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1202 symnum); 1203 } 1204 ventry = fetch_ventry(refobj, symnum); 1205 hash = elf_hash(name); 1206 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1207 } else { 1208 def = ref; 1209 defobj = refobj; 1210 } 1211 1212 /* 1213 * If we found no definition and the reference is weak, treat the 1214 * symbol as having the value zero. 1215 */ 1216 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1217 def = &sym_zero; 1218 defobj = obj_main; 1219 } 1220 1221 if (def != NULL) { 1222 *defobj_out = defobj; 1223 /* Record the information in the cache to avoid subsequent lookups. */ 1224 if (cache != NULL) { 1225 cache[symnum].sym = def; 1226 cache[symnum].obj = defobj; 1227 } 1228 } else { 1229 if (refobj != &obj_rtld) 1230 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1231 } 1232 return def; 1233 } 1234 1235 /* 1236 * Return the search path from the ldconfig hints file, reading it if 1237 * necessary. Returns NULL if there are problems with the hints file, 1238 * or if the search path there is empty. 1239 */ 1240 static const char * 1241 gethints(void) 1242 { 1243 static char *hints; 1244 1245 if (hints == NULL) { 1246 int fd; 1247 struct elfhints_hdr hdr; 1248 char *p; 1249 1250 /* Keep from trying again in case the hints file is bad. */ 1251 hints = ""; 1252 1253 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1254 return NULL; 1255 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1256 hdr.magic != ELFHINTS_MAGIC || 1257 hdr.version != 1) { 1258 close(fd); 1259 return NULL; 1260 } 1261 p = xmalloc(hdr.dirlistlen + 1); 1262 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1263 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1264 free(p); 1265 close(fd); 1266 return NULL; 1267 } 1268 hints = p; 1269 close(fd); 1270 } 1271 return hints[0] != '\0' ? hints : NULL; 1272 } 1273 1274 static void 1275 init_dag(Obj_Entry *root) 1276 { 1277 DoneList donelist; 1278 1279 donelist_init(&donelist); 1280 init_dag1(root, root, &donelist); 1281 } 1282 1283 static void 1284 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1285 { 1286 const Needed_Entry *needed; 1287 1288 if (donelist_check(dlp, obj)) 1289 return; 1290 1291 obj->refcount++; 1292 objlist_push_tail(&obj->dldags, root); 1293 objlist_push_tail(&root->dagmembers, obj); 1294 for (needed = obj->needed; needed != NULL; needed = needed->next) 1295 if (needed->obj != NULL) 1296 init_dag1(root, needed->obj, dlp); 1297 } 1298 1299 /* 1300 * Initialize the dynamic linker. The argument is the address at which 1301 * the dynamic linker has been mapped into memory. The primary task of 1302 * this function is to relocate the dynamic linker. 1303 */ 1304 static void 1305 init_rtld(caddr_t mapbase) 1306 { 1307 Obj_Entry objtmp; /* Temporary rtld object */ 1308 1309 /* 1310 * Conjure up an Obj_Entry structure for the dynamic linker. 1311 * 1312 * The "path" member can't be initialized yet because string constatns 1313 * cannot yet be acessed. Below we will set it correctly. 1314 */ 1315 memset(&objtmp, 0, sizeof(objtmp)); 1316 objtmp.path = NULL; 1317 objtmp.rtld = true; 1318 objtmp.mapbase = mapbase; 1319 #ifdef PIC 1320 objtmp.relocbase = mapbase; 1321 #endif 1322 if (RTLD_IS_DYNAMIC()) { 1323 objtmp.dynamic = rtld_dynamic(&objtmp); 1324 digest_dynamic(&objtmp, 1); 1325 assert(objtmp.needed == NULL); 1326 #if !defined(__mips__) 1327 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1328 assert(!objtmp.textrel); 1329 #endif 1330 1331 /* 1332 * Temporarily put the dynamic linker entry into the object list, so 1333 * that symbols can be found. 1334 */ 1335 1336 relocate_objects(&objtmp, true, &objtmp); 1337 } 1338 1339 /* Initialize the object list. */ 1340 obj_tail = &obj_list; 1341 1342 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1343 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1344 1345 /* Replace the path with a dynamically allocated copy. */ 1346 obj_rtld.path = xstrdup(PATH_RTLD); 1347 1348 r_debug.r_brk = r_debug_state; 1349 r_debug.r_state = RT_CONSISTENT; 1350 } 1351 1352 /* 1353 * Add the init functions from a needed object list (and its recursive 1354 * needed objects) to "list". This is not used directly; it is a helper 1355 * function for initlist_add_objects(). The write lock must be held 1356 * when this function is called. 1357 */ 1358 static void 1359 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1360 { 1361 /* Recursively process the successor needed objects. */ 1362 if (needed->next != NULL) 1363 initlist_add_neededs(needed->next, list); 1364 1365 /* Process the current needed object. */ 1366 if (needed->obj != NULL) 1367 initlist_add_objects(needed->obj, &needed->obj->next, list); 1368 } 1369 1370 /* 1371 * Scan all of the DAGs rooted in the range of objects from "obj" to 1372 * "tail" and add their init functions to "list". This recurses over 1373 * the DAGs and ensure the proper init ordering such that each object's 1374 * needed libraries are initialized before the object itself. At the 1375 * same time, this function adds the objects to the global finalization 1376 * list "list_fini" in the opposite order. The write lock must be 1377 * held when this function is called. 1378 */ 1379 static void 1380 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1381 { 1382 if (obj->init_done) 1383 return; 1384 obj->init_done = true; 1385 1386 /* Recursively process the successor objects. */ 1387 if (&obj->next != tail) 1388 initlist_add_objects(obj->next, tail, list); 1389 1390 /* Recursively process the needed objects. */ 1391 if (obj->needed != NULL) 1392 initlist_add_neededs(obj->needed, list); 1393 1394 /* Add the object to the init list. */ 1395 if (obj->init != (Elf_Addr)NULL) 1396 objlist_push_tail(list, obj); 1397 1398 /* Add the object to the global fini list in the reverse order. */ 1399 if (obj->fini != (Elf_Addr)NULL) 1400 objlist_push_head(&list_fini, obj); 1401 } 1402 1403 #ifndef FPTR_TARGET 1404 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1405 #endif 1406 1407 static bool 1408 is_exported(const Elf_Sym *def) 1409 { 1410 Elf_Addr value; 1411 const func_ptr_type *p; 1412 1413 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1414 for (p = exports; *p != NULL; p++) 1415 if (FPTR_TARGET(*p) == value) 1416 return true; 1417 return false; 1418 } 1419 1420 /* 1421 * Given a shared object, traverse its list of needed objects, and load 1422 * each of them. Returns 0 on success. Generates an error message and 1423 * returns -1 on failure. 1424 */ 1425 static int 1426 load_needed_objects(Obj_Entry *first) 1427 { 1428 Obj_Entry *obj, *obj1; 1429 1430 for (obj = first; obj != NULL; obj = obj->next) { 1431 Needed_Entry *needed; 1432 1433 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1434 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj); 1435 if (obj1 == NULL && !ld_tracing) 1436 return -1; 1437 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1438 dbg("obj %s nodelete", obj1->path); 1439 init_dag(obj1); 1440 ref_dag(obj1); 1441 obj1->ref_nodel = true; 1442 } 1443 } 1444 } 1445 1446 return 0; 1447 } 1448 1449 static int 1450 load_preload_objects(void) 1451 { 1452 char *p = ld_preload; 1453 static const char delim[] = " \t:;"; 1454 1455 if (p == NULL) 1456 return 0; 1457 1458 p += strspn(p, delim); 1459 while (*p != '\0') { 1460 size_t len = strcspn(p, delim); 1461 char savech; 1462 1463 savech = p[len]; 1464 p[len] = '\0'; 1465 if (load_object(p, NULL) == NULL) 1466 return -1; /* XXX - cleanup */ 1467 p[len] = savech; 1468 p += len; 1469 p += strspn(p, delim); 1470 } 1471 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1472 return 0; 1473 } 1474 1475 /* 1476 * Load a shared object into memory, if it is not already loaded. 1477 * 1478 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1479 * on failure. 1480 */ 1481 static Obj_Entry * 1482 load_object(const char *name, const Obj_Entry *refobj) 1483 { 1484 Obj_Entry *obj; 1485 int fd = -1; 1486 struct stat sb; 1487 char *path; 1488 1489 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1490 if (object_match_name(obj, name)) 1491 return obj; 1492 1493 path = find_library(name, refobj); 1494 if (path == NULL) 1495 return NULL; 1496 1497 /* 1498 * If we didn't find a match by pathname, open the file and check 1499 * again by device and inode. This avoids false mismatches caused 1500 * by multiple links or ".." in pathnames. 1501 * 1502 * To avoid a race, we open the file and use fstat() rather than 1503 * using stat(). 1504 */ 1505 if ((fd = open(path, O_RDONLY)) == -1) { 1506 _rtld_error("Cannot open \"%s\"", path); 1507 free(path); 1508 return NULL; 1509 } 1510 if (fstat(fd, &sb) == -1) { 1511 _rtld_error("Cannot fstat \"%s\"", path); 1512 close(fd); 1513 free(path); 1514 return NULL; 1515 } 1516 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1517 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1518 close(fd); 1519 break; 1520 } 1521 } 1522 if (obj != NULL) { 1523 object_add_name(obj, name); 1524 free(path); 1525 close(fd); 1526 return obj; 1527 } 1528 1529 /* First use of this object, so we must map it in */ 1530 obj = do_load_object(fd, name, path, &sb); 1531 if (obj == NULL) 1532 free(path); 1533 close(fd); 1534 1535 return obj; 1536 } 1537 1538 static Obj_Entry * 1539 do_load_object(int fd, const char *name, char *path, struct stat *sbp) 1540 { 1541 Obj_Entry *obj; 1542 struct statfs fs; 1543 1544 /* 1545 * but first, make sure that environment variables haven't been 1546 * used to circumvent the noexec flag on a filesystem. 1547 */ 1548 if (dangerous_ld_env) { 1549 if (fstatfs(fd, &fs) != 0) { 1550 _rtld_error("Cannot fstatfs \"%s\"", path); 1551 return NULL; 1552 } 1553 if (fs.f_flags & MNT_NOEXEC) { 1554 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1555 return NULL; 1556 } 1557 } 1558 dbg("loading \"%s\"", path); 1559 obj = map_object(fd, path, sbp); 1560 if (obj == NULL) 1561 return NULL; 1562 1563 object_add_name(obj, name); 1564 obj->path = path; 1565 digest_dynamic(obj, 0); 1566 1567 *obj_tail = obj; 1568 obj_tail = &obj->next; 1569 obj_count++; 1570 obj_loads++; 1571 linkmap_add(obj); /* for GDB & dlinfo() */ 1572 1573 dbg(" %p .. %p: %s", obj->mapbase, 1574 obj->mapbase + obj->mapsize - 1, obj->path); 1575 if (obj->textrel) 1576 dbg(" WARNING: %s has impure text", obj->path); 1577 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1578 obj->path); 1579 1580 return obj; 1581 } 1582 1583 static Obj_Entry * 1584 obj_from_addr(const void *addr) 1585 { 1586 Obj_Entry *obj; 1587 1588 for (obj = obj_list; obj != NULL; obj = obj->next) { 1589 if (addr < (void *) obj->mapbase) 1590 continue; 1591 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1592 return obj; 1593 } 1594 return NULL; 1595 } 1596 1597 /* 1598 * Call the finalization functions for each of the objects in "list" 1599 * which are unreferenced. All of the objects are expected to have 1600 * non-NULL fini functions. 1601 */ 1602 static void 1603 objlist_call_fini(Objlist *list, int *lockstate) 1604 { 1605 Objlist_Entry *elm; 1606 char *saved_msg; 1607 1608 /* 1609 * Preserve the current error message since a fini function might 1610 * call into the dynamic linker and overwrite it. 1611 */ 1612 saved_msg = errmsg_save(); 1613 wlock_release(rtld_bind_lock, *lockstate); 1614 STAILQ_FOREACH(elm, list, link) { 1615 if (elm->obj->refcount == 0) { 1616 dbg("calling fini function for %s at %p", elm->obj->path, 1617 (void *)elm->obj->fini); 1618 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1619 elm->obj->path); 1620 call_initfini_pointer(elm->obj, elm->obj->fini); 1621 } 1622 } 1623 *lockstate = wlock_acquire(rtld_bind_lock); 1624 errmsg_restore(saved_msg); 1625 } 1626 1627 /* 1628 * Call the initialization functions for each of the objects in 1629 * "list". All of the objects are expected to have non-NULL init 1630 * functions. 1631 */ 1632 static void 1633 objlist_call_init(Objlist *list, int *lockstate) 1634 { 1635 Objlist_Entry *elm; 1636 char *saved_msg; 1637 1638 /* 1639 * Preserve the current error message since an init function might 1640 * call into the dynamic linker and overwrite it. 1641 */ 1642 saved_msg = errmsg_save(); 1643 wlock_release(rtld_bind_lock, *lockstate); 1644 STAILQ_FOREACH(elm, list, link) { 1645 dbg("calling init function for %s at %p", elm->obj->path, 1646 (void *)elm->obj->init); 1647 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1648 elm->obj->path); 1649 call_initfini_pointer(elm->obj, elm->obj->init); 1650 } 1651 *lockstate = wlock_acquire(rtld_bind_lock); 1652 errmsg_restore(saved_msg); 1653 } 1654 1655 static void 1656 objlist_clear(Objlist *list) 1657 { 1658 Objlist_Entry *elm; 1659 1660 while (!STAILQ_EMPTY(list)) { 1661 elm = STAILQ_FIRST(list); 1662 STAILQ_REMOVE_HEAD(list, link); 1663 free(elm); 1664 } 1665 } 1666 1667 static Objlist_Entry * 1668 objlist_find(Objlist *list, const Obj_Entry *obj) 1669 { 1670 Objlist_Entry *elm; 1671 1672 STAILQ_FOREACH(elm, list, link) 1673 if (elm->obj == obj) 1674 return elm; 1675 return NULL; 1676 } 1677 1678 static void 1679 objlist_init(Objlist *list) 1680 { 1681 STAILQ_INIT(list); 1682 } 1683 1684 static void 1685 objlist_push_head(Objlist *list, Obj_Entry *obj) 1686 { 1687 Objlist_Entry *elm; 1688 1689 elm = NEW(Objlist_Entry); 1690 elm->obj = obj; 1691 STAILQ_INSERT_HEAD(list, elm, link); 1692 } 1693 1694 static void 1695 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1696 { 1697 Objlist_Entry *elm; 1698 1699 elm = NEW(Objlist_Entry); 1700 elm->obj = obj; 1701 STAILQ_INSERT_TAIL(list, elm, link); 1702 } 1703 1704 static void 1705 objlist_remove(Objlist *list, Obj_Entry *obj) 1706 { 1707 Objlist_Entry *elm; 1708 1709 if ((elm = objlist_find(list, obj)) != NULL) { 1710 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1711 free(elm); 1712 } 1713 } 1714 1715 /* 1716 * Remove all of the unreferenced objects from "list". 1717 */ 1718 static void 1719 objlist_remove_unref(Objlist *list) 1720 { 1721 Objlist newlist; 1722 Objlist_Entry *elm; 1723 1724 STAILQ_INIT(&newlist); 1725 while (!STAILQ_EMPTY(list)) { 1726 elm = STAILQ_FIRST(list); 1727 STAILQ_REMOVE_HEAD(list, link); 1728 if (elm->obj->refcount == 0) 1729 free(elm); 1730 else 1731 STAILQ_INSERT_TAIL(&newlist, elm, link); 1732 } 1733 *list = newlist; 1734 } 1735 1736 /* 1737 * Relocate newly-loaded shared objects. The argument is a pointer to 1738 * the Obj_Entry for the first such object. All objects from the first 1739 * to the end of the list of objects are relocated. Returns 0 on success, 1740 * or -1 on failure. 1741 */ 1742 static int 1743 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1744 { 1745 Obj_Entry *obj; 1746 1747 for (obj = first; obj != NULL; obj = obj->next) { 1748 if (obj != rtldobj) 1749 dbg("relocating \"%s\"", obj->path); 1750 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1751 obj->symtab == NULL || obj->strtab == NULL) { 1752 _rtld_error("%s: Shared object has no run-time symbol table", 1753 obj->path); 1754 return -1; 1755 } 1756 1757 if (obj->textrel) { 1758 /* There are relocations to the write-protected text segment. */ 1759 if (mprotect(obj->mapbase, obj->textsize, 1760 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1761 _rtld_error("%s: Cannot write-enable text segment: %s", 1762 obj->path, strerror(errno)); 1763 return -1; 1764 } 1765 } 1766 1767 /* Process the non-PLT relocations. */ 1768 if (reloc_non_plt(obj, rtldobj)) 1769 return -1; 1770 1771 if (obj->textrel) { /* Re-protected the text segment. */ 1772 if (mprotect(obj->mapbase, obj->textsize, 1773 PROT_READ|PROT_EXEC) == -1) { 1774 _rtld_error("%s: Cannot write-protect text segment: %s", 1775 obj->path, strerror(errno)); 1776 return -1; 1777 } 1778 } 1779 1780 /* Process the PLT relocations. */ 1781 if (reloc_plt(obj) == -1) 1782 return -1; 1783 /* Relocate the jump slots if we are doing immediate binding. */ 1784 if (obj->bind_now || bind_now) 1785 if (reloc_jmpslots(obj) == -1) 1786 return -1; 1787 1788 1789 /* 1790 * Set up the magic number and version in the Obj_Entry. These 1791 * were checked in the crt1.o from the original ElfKit, so we 1792 * set them for backward compatibility. 1793 */ 1794 obj->magic = RTLD_MAGIC; 1795 obj->version = RTLD_VERSION; 1796 1797 /* Set the special PLT or GOT entries. */ 1798 init_pltgot(obj); 1799 } 1800 1801 return 0; 1802 } 1803 1804 /* 1805 * Cleanup procedure. It will be called (by the atexit mechanism) just 1806 * before the process exits. 1807 */ 1808 static void 1809 rtld_exit(void) 1810 { 1811 Obj_Entry *obj; 1812 int lockstate; 1813 1814 lockstate = wlock_acquire(rtld_bind_lock); 1815 dbg("rtld_exit()"); 1816 /* Clear all the reference counts so the fini functions will be called. */ 1817 for (obj = obj_list; obj != NULL; obj = obj->next) 1818 obj->refcount = 0; 1819 objlist_call_fini(&list_fini, &lockstate); 1820 /* No need to remove the items from the list, since we are exiting. */ 1821 if (!libmap_disable) 1822 lm_fini(); 1823 wlock_release(rtld_bind_lock, lockstate); 1824 } 1825 1826 static void * 1827 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1828 { 1829 #ifdef COMPAT_32BIT 1830 const char *trans; 1831 #endif 1832 if (path == NULL) 1833 return (NULL); 1834 1835 path += strspn(path, ":;"); 1836 while (*path != '\0') { 1837 size_t len; 1838 char *res; 1839 1840 len = strcspn(path, ":;"); 1841 #ifdef COMPAT_32BIT 1842 trans = lm_findn(NULL, path, len); 1843 if (trans) 1844 res = callback(trans, strlen(trans), arg); 1845 else 1846 #endif 1847 res = callback(path, len, arg); 1848 1849 if (res != NULL) 1850 return (res); 1851 1852 path += len; 1853 path += strspn(path, ":;"); 1854 } 1855 1856 return (NULL); 1857 } 1858 1859 struct try_library_args { 1860 const char *name; 1861 size_t namelen; 1862 char *buffer; 1863 size_t buflen; 1864 }; 1865 1866 static void * 1867 try_library_path(const char *dir, size_t dirlen, void *param) 1868 { 1869 struct try_library_args *arg; 1870 1871 arg = param; 1872 if (*dir == '/' || trust) { 1873 char *pathname; 1874 1875 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1876 return (NULL); 1877 1878 pathname = arg->buffer; 1879 strncpy(pathname, dir, dirlen); 1880 pathname[dirlen] = '/'; 1881 strcpy(pathname + dirlen + 1, arg->name); 1882 1883 dbg(" Trying \"%s\"", pathname); 1884 if (access(pathname, F_OK) == 0) { /* We found it */ 1885 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1886 strcpy(pathname, arg->buffer); 1887 return (pathname); 1888 } 1889 } 1890 return (NULL); 1891 } 1892 1893 static char * 1894 search_library_path(const char *name, const char *path) 1895 { 1896 char *p; 1897 struct try_library_args arg; 1898 1899 if (path == NULL) 1900 return NULL; 1901 1902 arg.name = name; 1903 arg.namelen = strlen(name); 1904 arg.buffer = xmalloc(PATH_MAX); 1905 arg.buflen = PATH_MAX; 1906 1907 p = path_enumerate(path, try_library_path, &arg); 1908 1909 free(arg.buffer); 1910 1911 return (p); 1912 } 1913 1914 int 1915 dlclose(void *handle) 1916 { 1917 Obj_Entry *root; 1918 int lockstate; 1919 1920 lockstate = wlock_acquire(rtld_bind_lock); 1921 root = dlcheck(handle); 1922 if (root == NULL) { 1923 wlock_release(rtld_bind_lock, lockstate); 1924 return -1; 1925 } 1926 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1927 root->path); 1928 1929 /* Unreference the object and its dependencies. */ 1930 root->dl_refcount--; 1931 1932 unref_dag(root); 1933 1934 if (root->refcount == 0) { 1935 /* 1936 * The object is no longer referenced, so we must unload it. 1937 * First, call the fini functions. 1938 */ 1939 objlist_call_fini(&list_fini, &lockstate); 1940 objlist_remove_unref(&list_fini); 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; 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 1996 objlist_init(&initlist); 1997 1998 lockstate = wlock_acquire(rtld_bind_lock); 1999 GDB_STATE(RT_ADD,NULL); 2000 2001 old_obj_tail = obj_tail; 2002 obj = NULL; 2003 if (name == NULL) { 2004 obj = obj_main; 2005 obj->refcount++; 2006 } else { 2007 obj = load_object(name, obj_main); 2008 } 2009 2010 if (obj) { 2011 obj->dl_refcount++; 2012 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2013 objlist_push_tail(&list_global, obj); 2014 mode &= RTLD_MODEMASK; 2015 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2016 assert(*old_obj_tail == obj); 2017 result = load_needed_objects(obj); 2018 init_dag(obj); 2019 if (result != -1) 2020 result = rtld_verify_versions(&obj->dagmembers); 2021 if (result != -1 && ld_tracing) 2022 goto trace; 2023 if (result == -1 || 2024 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2025 obj->dl_refcount--; 2026 unref_dag(obj); 2027 if (obj->refcount == 0) 2028 unload_object(obj); 2029 obj = NULL; 2030 } else { 2031 /* Make list of init functions to call. */ 2032 initlist_add_objects(obj, &obj->next, &initlist); 2033 } 2034 } else { 2035 2036 /* Bump the reference counts for objects on this DAG. */ 2037 ref_dag(obj); 2038 2039 if (ld_tracing) 2040 goto trace; 2041 } 2042 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2043 dbg("obj %s nodelete", obj->path); 2044 ref_dag(obj); 2045 obj->z_nodelete = obj->ref_nodel = true; 2046 } 2047 } 2048 2049 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2050 name); 2051 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2052 2053 /* Call the init functions. */ 2054 objlist_call_init(&initlist, &lockstate); 2055 objlist_clear(&initlist); 2056 wlock_release(rtld_bind_lock, lockstate); 2057 return obj; 2058 trace: 2059 trace_loaded_objects(obj); 2060 wlock_release(rtld_bind_lock, lockstate); 2061 exit(0); 2062 } 2063 2064 static void * 2065 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2066 int flags) 2067 { 2068 DoneList donelist; 2069 const Obj_Entry *obj, *defobj; 2070 const Elf_Sym *def, *symp; 2071 unsigned long hash; 2072 int lockstate; 2073 2074 hash = elf_hash(name); 2075 def = NULL; 2076 defobj = NULL; 2077 flags |= SYMLOOK_IN_PLT; 2078 2079 lockstate = rlock_acquire(rtld_bind_lock); 2080 if (handle == NULL || handle == RTLD_NEXT || 2081 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2082 2083 if ((obj = obj_from_addr(retaddr)) == NULL) { 2084 _rtld_error("Cannot determine caller's shared object"); 2085 rlock_release(rtld_bind_lock, lockstate); 2086 return NULL; 2087 } 2088 if (handle == NULL) { /* Just the caller's shared object. */ 2089 def = symlook_obj(name, hash, obj, ve, flags); 2090 defobj = obj; 2091 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2092 handle == RTLD_SELF) { /* ... caller included */ 2093 if (handle == RTLD_NEXT) 2094 obj = obj->next; 2095 for (; obj != NULL; obj = obj->next) { 2096 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2097 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2098 def = symp; 2099 defobj = obj; 2100 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2101 break; 2102 } 2103 } 2104 } 2105 /* 2106 * Search the dynamic linker itself, and possibly resolve the 2107 * symbol from there. This is how the application links to 2108 * dynamic linker services such as dlopen. Only the values listed 2109 * in the "exports" array can be resolved from the dynamic linker. 2110 */ 2111 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2112 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2113 if (symp != NULL && is_exported(symp)) { 2114 def = symp; 2115 defobj = &obj_rtld; 2116 } 2117 } 2118 } else { 2119 assert(handle == RTLD_DEFAULT); 2120 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2121 } 2122 } else { 2123 if ((obj = dlcheck(handle)) == NULL) { 2124 rlock_release(rtld_bind_lock, lockstate); 2125 return NULL; 2126 } 2127 2128 donelist_init(&donelist); 2129 if (obj->mainprog) { 2130 /* Search main program and all libraries loaded by it. */ 2131 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2132 &donelist); 2133 } else { 2134 Needed_Entry fake; 2135 2136 /* Search the whole DAG rooted at the given object. */ 2137 fake.next = NULL; 2138 fake.obj = (Obj_Entry *)obj; 2139 fake.name = 0; 2140 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2141 &donelist); 2142 } 2143 } 2144 2145 if (def != NULL) { 2146 rlock_release(rtld_bind_lock, lockstate); 2147 2148 /* 2149 * The value required by the caller is derived from the value 2150 * of the symbol. For the ia64 architecture, we need to 2151 * construct a function descriptor which the caller can use to 2152 * call the function with the right 'gp' value. For other 2153 * architectures and for non-functions, the value is simply 2154 * the relocated value of the symbol. 2155 */ 2156 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2157 return make_function_pointer(def, defobj); 2158 else 2159 return defobj->relocbase + def->st_value; 2160 } 2161 2162 _rtld_error("Undefined symbol \"%s\"", name); 2163 rlock_release(rtld_bind_lock, lockstate); 2164 return NULL; 2165 } 2166 2167 void * 2168 dlsym(void *handle, const char *name) 2169 { 2170 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2171 SYMLOOK_DLSYM); 2172 } 2173 2174 dlfunc_t 2175 dlfunc(void *handle, const char *name) 2176 { 2177 union { 2178 void *d; 2179 dlfunc_t f; 2180 } rv; 2181 2182 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2183 SYMLOOK_DLSYM); 2184 return (rv.f); 2185 } 2186 2187 void * 2188 dlvsym(void *handle, const char *name, const char *version) 2189 { 2190 Ver_Entry ventry; 2191 2192 ventry.name = version; 2193 ventry.file = NULL; 2194 ventry.hash = elf_hash(version); 2195 ventry.flags= 0; 2196 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2197 SYMLOOK_DLSYM); 2198 } 2199 2200 int 2201 dladdr(const void *addr, Dl_info *info) 2202 { 2203 const Obj_Entry *obj; 2204 const Elf_Sym *def; 2205 void *symbol_addr; 2206 unsigned long symoffset; 2207 int lockstate; 2208 2209 lockstate = rlock_acquire(rtld_bind_lock); 2210 obj = obj_from_addr(addr); 2211 if (obj == NULL) { 2212 _rtld_error("No shared object contains address"); 2213 rlock_release(rtld_bind_lock, lockstate); 2214 return 0; 2215 } 2216 info->dli_fname = obj->path; 2217 info->dli_fbase = obj->mapbase; 2218 info->dli_saddr = (void *)0; 2219 info->dli_sname = NULL; 2220 2221 /* 2222 * Walk the symbol list looking for the symbol whose address is 2223 * closest to the address sent in. 2224 */ 2225 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2226 def = obj->symtab + symoffset; 2227 2228 /* 2229 * For skip the symbol if st_shndx is either SHN_UNDEF or 2230 * SHN_COMMON. 2231 */ 2232 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2233 continue; 2234 2235 /* 2236 * If the symbol is greater than the specified address, or if it 2237 * is further away from addr than the current nearest symbol, 2238 * then reject it. 2239 */ 2240 symbol_addr = obj->relocbase + def->st_value; 2241 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2242 continue; 2243 2244 /* Update our idea of the nearest symbol. */ 2245 info->dli_sname = obj->strtab + def->st_name; 2246 info->dli_saddr = symbol_addr; 2247 2248 /* Exact match? */ 2249 if (info->dli_saddr == addr) 2250 break; 2251 } 2252 rlock_release(rtld_bind_lock, lockstate); 2253 return 1; 2254 } 2255 2256 int 2257 dlinfo(void *handle, int request, void *p) 2258 { 2259 const Obj_Entry *obj; 2260 int error, lockstate; 2261 2262 lockstate = rlock_acquire(rtld_bind_lock); 2263 2264 if (handle == NULL || handle == RTLD_SELF) { 2265 void *retaddr; 2266 2267 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2268 if ((obj = obj_from_addr(retaddr)) == NULL) 2269 _rtld_error("Cannot determine caller's shared object"); 2270 } else 2271 obj = dlcheck(handle); 2272 2273 if (obj == NULL) { 2274 rlock_release(rtld_bind_lock, lockstate); 2275 return (-1); 2276 } 2277 2278 error = 0; 2279 switch (request) { 2280 case RTLD_DI_LINKMAP: 2281 *((struct link_map const **)p) = &obj->linkmap; 2282 break; 2283 case RTLD_DI_ORIGIN: 2284 error = rtld_dirname(obj->path, p); 2285 break; 2286 2287 case RTLD_DI_SERINFOSIZE: 2288 case RTLD_DI_SERINFO: 2289 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2290 break; 2291 2292 default: 2293 _rtld_error("Invalid request %d passed to dlinfo()", request); 2294 error = -1; 2295 } 2296 2297 rlock_release(rtld_bind_lock, lockstate); 2298 2299 return (error); 2300 } 2301 2302 int 2303 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2304 { 2305 struct dl_phdr_info phdr_info; 2306 const Obj_Entry *obj; 2307 int error, bind_lockstate, phdr_lockstate; 2308 2309 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2310 bind_lockstate = rlock_acquire(rtld_bind_lock); 2311 2312 error = 0; 2313 2314 for (obj = obj_list; obj != NULL; obj = obj->next) { 2315 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2316 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2317 STAILQ_FIRST(&obj->names)->name : obj->path; 2318 phdr_info.dlpi_phdr = obj->phdr; 2319 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2320 phdr_info.dlpi_tls_modid = obj->tlsindex; 2321 phdr_info.dlpi_tls_data = obj->tlsinit; 2322 phdr_info.dlpi_adds = obj_loads; 2323 phdr_info.dlpi_subs = obj_loads - obj_count; 2324 2325 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2326 break; 2327 2328 } 2329 rlock_release(rtld_bind_lock, bind_lockstate); 2330 wlock_release(rtld_phdr_lock, phdr_lockstate); 2331 2332 return (error); 2333 } 2334 2335 struct fill_search_info_args { 2336 int request; 2337 unsigned int flags; 2338 Dl_serinfo *serinfo; 2339 Dl_serpath *serpath; 2340 char *strspace; 2341 }; 2342 2343 static void * 2344 fill_search_info(const char *dir, size_t dirlen, void *param) 2345 { 2346 struct fill_search_info_args *arg; 2347 2348 arg = param; 2349 2350 if (arg->request == RTLD_DI_SERINFOSIZE) { 2351 arg->serinfo->dls_cnt ++; 2352 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2353 } else { 2354 struct dl_serpath *s_entry; 2355 2356 s_entry = arg->serpath; 2357 s_entry->dls_name = arg->strspace; 2358 s_entry->dls_flags = arg->flags; 2359 2360 strncpy(arg->strspace, dir, dirlen); 2361 arg->strspace[dirlen] = '\0'; 2362 2363 arg->strspace += dirlen + 1; 2364 arg->serpath++; 2365 } 2366 2367 return (NULL); 2368 } 2369 2370 static int 2371 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2372 { 2373 struct dl_serinfo _info; 2374 struct fill_search_info_args args; 2375 2376 args.request = RTLD_DI_SERINFOSIZE; 2377 args.serinfo = &_info; 2378 2379 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2380 _info.dls_cnt = 0; 2381 2382 path_enumerate(ld_library_path, fill_search_info, &args); 2383 path_enumerate(obj->rpath, fill_search_info, &args); 2384 path_enumerate(gethints(), fill_search_info, &args); 2385 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2386 2387 2388 if (request == RTLD_DI_SERINFOSIZE) { 2389 info->dls_size = _info.dls_size; 2390 info->dls_cnt = _info.dls_cnt; 2391 return (0); 2392 } 2393 2394 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2395 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2396 return (-1); 2397 } 2398 2399 args.request = RTLD_DI_SERINFO; 2400 args.serinfo = info; 2401 args.serpath = &info->dls_serpath[0]; 2402 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2403 2404 args.flags = LA_SER_LIBPATH; 2405 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2406 return (-1); 2407 2408 args.flags = LA_SER_RUNPATH; 2409 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2410 return (-1); 2411 2412 args.flags = LA_SER_CONFIG; 2413 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2414 return (-1); 2415 2416 args.flags = LA_SER_DEFAULT; 2417 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2418 return (-1); 2419 return (0); 2420 } 2421 2422 static int 2423 rtld_dirname(const char *path, char *bname) 2424 { 2425 const char *endp; 2426 2427 /* Empty or NULL string gets treated as "." */ 2428 if (path == NULL || *path == '\0') { 2429 bname[0] = '.'; 2430 bname[1] = '\0'; 2431 return (0); 2432 } 2433 2434 /* Strip trailing slashes */ 2435 endp = path + strlen(path) - 1; 2436 while (endp > path && *endp == '/') 2437 endp--; 2438 2439 /* Find the start of the dir */ 2440 while (endp > path && *endp != '/') 2441 endp--; 2442 2443 /* Either the dir is "/" or there are no slashes */ 2444 if (endp == path) { 2445 bname[0] = *endp == '/' ? '/' : '.'; 2446 bname[1] = '\0'; 2447 return (0); 2448 } else { 2449 do { 2450 endp--; 2451 } while (endp > path && *endp == '/'); 2452 } 2453 2454 if (endp - path + 2 > PATH_MAX) 2455 { 2456 _rtld_error("Filename is too long: %s", path); 2457 return(-1); 2458 } 2459 2460 strncpy(bname, path, endp - path + 1); 2461 bname[endp - path + 1] = '\0'; 2462 return (0); 2463 } 2464 2465 static int 2466 rtld_dirname_abs(const char *path, char *base) 2467 { 2468 char base_rel[PATH_MAX]; 2469 2470 if (rtld_dirname(path, base) == -1) 2471 return (-1); 2472 if (base[0] == '/') 2473 return (0); 2474 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2475 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2476 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2477 return (-1); 2478 strcpy(base, base_rel); 2479 return (0); 2480 } 2481 2482 static void 2483 linkmap_add(Obj_Entry *obj) 2484 { 2485 struct link_map *l = &obj->linkmap; 2486 struct link_map *prev; 2487 2488 obj->linkmap.l_name = obj->path; 2489 obj->linkmap.l_addr = obj->mapbase; 2490 obj->linkmap.l_ld = obj->dynamic; 2491 #ifdef __mips__ 2492 /* GDB needs load offset on MIPS to use the symbols */ 2493 obj->linkmap.l_offs = obj->relocbase; 2494 #endif 2495 2496 if (r_debug.r_map == NULL) { 2497 r_debug.r_map = l; 2498 return; 2499 } 2500 2501 /* 2502 * Scan to the end of the list, but not past the entry for the 2503 * dynamic linker, which we want to keep at the very end. 2504 */ 2505 for (prev = r_debug.r_map; 2506 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2507 prev = prev->l_next) 2508 ; 2509 2510 /* Link in the new entry. */ 2511 l->l_prev = prev; 2512 l->l_next = prev->l_next; 2513 if (l->l_next != NULL) 2514 l->l_next->l_prev = l; 2515 prev->l_next = l; 2516 } 2517 2518 static void 2519 linkmap_delete(Obj_Entry *obj) 2520 { 2521 struct link_map *l = &obj->linkmap; 2522 2523 if (l->l_prev == NULL) { 2524 if ((r_debug.r_map = l->l_next) != NULL) 2525 l->l_next->l_prev = NULL; 2526 return; 2527 } 2528 2529 if ((l->l_prev->l_next = l->l_next) != NULL) 2530 l->l_next->l_prev = l->l_prev; 2531 } 2532 2533 /* 2534 * Function for the debugger to set a breakpoint on to gain control. 2535 * 2536 * The two parameters allow the debugger to easily find and determine 2537 * what the runtime loader is doing and to whom it is doing it. 2538 * 2539 * When the loadhook trap is hit (r_debug_state, set at program 2540 * initialization), the arguments can be found on the stack: 2541 * 2542 * +8 struct link_map *m 2543 * +4 struct r_debug *rd 2544 * +0 RetAddr 2545 */ 2546 void 2547 r_debug_state(struct r_debug* rd, struct link_map *m) 2548 { 2549 } 2550 2551 /* 2552 * Get address of the pointer variable in the main program. 2553 */ 2554 static const void ** 2555 get_program_var_addr(const char *name) 2556 { 2557 const Obj_Entry *obj; 2558 unsigned long hash; 2559 2560 hash = elf_hash(name); 2561 for (obj = obj_main; obj != NULL; obj = obj->next) { 2562 const Elf_Sym *def; 2563 2564 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2565 const void **addr; 2566 2567 addr = (const void **)(obj->relocbase + def->st_value); 2568 return addr; 2569 } 2570 } 2571 return NULL; 2572 } 2573 2574 /* 2575 * Set a pointer variable in the main program to the given value. This 2576 * is used to set key variables such as "environ" before any of the 2577 * init functions are called. 2578 */ 2579 static void 2580 set_program_var(const char *name, const void *value) 2581 { 2582 const void **addr; 2583 2584 if ((addr = get_program_var_addr(name)) != NULL) { 2585 dbg("\"%s\": *%p <-- %p", name, addr, value); 2586 *addr = value; 2587 } 2588 } 2589 2590 /* 2591 * Given a symbol name in a referencing object, find the corresponding 2592 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2593 * no definition was found. Returns a pointer to the Obj_Entry of the 2594 * defining object via the reference parameter DEFOBJ_OUT. 2595 */ 2596 static const Elf_Sym * 2597 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2598 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2599 { 2600 DoneList donelist; 2601 const Elf_Sym *def; 2602 const Elf_Sym *symp; 2603 const Obj_Entry *obj; 2604 const Obj_Entry *defobj; 2605 const Objlist_Entry *elm; 2606 def = NULL; 2607 defobj = NULL; 2608 donelist_init(&donelist); 2609 2610 /* Look first in the referencing object if linked symbolically. */ 2611 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2612 symp = symlook_obj(name, hash, refobj, ventry, flags); 2613 if (symp != NULL) { 2614 def = symp; 2615 defobj = refobj; 2616 } 2617 } 2618 2619 /* Search all objects loaded at program start up. */ 2620 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2621 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2622 &donelist); 2623 if (symp != NULL && 2624 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2625 def = symp; 2626 defobj = obj; 2627 } 2628 } 2629 2630 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2631 STAILQ_FOREACH(elm, &list_global, link) { 2632 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2633 break; 2634 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2635 flags, &donelist); 2636 if (symp != NULL && 2637 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2638 def = symp; 2639 defobj = obj; 2640 } 2641 } 2642 2643 /* Search all dlopened DAGs containing the referencing object. */ 2644 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2645 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2646 break; 2647 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2648 flags, &donelist); 2649 if (symp != NULL && 2650 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2651 def = symp; 2652 defobj = obj; 2653 } 2654 } 2655 2656 /* 2657 * Search the dynamic linker itself, and possibly resolve the 2658 * symbol from there. This is how the application links to 2659 * dynamic linker services such as dlopen. Only the values listed 2660 * in the "exports" array can be resolved from the dynamic linker. 2661 */ 2662 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2663 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2664 if (symp != NULL && is_exported(symp)) { 2665 def = symp; 2666 defobj = &obj_rtld; 2667 } 2668 } 2669 2670 if (def != NULL) 2671 *defobj_out = defobj; 2672 return def; 2673 } 2674 2675 static const Elf_Sym * 2676 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2677 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2678 DoneList *dlp) 2679 { 2680 const Elf_Sym *symp; 2681 const Elf_Sym *def; 2682 const Obj_Entry *defobj; 2683 const Objlist_Entry *elm; 2684 2685 def = NULL; 2686 defobj = NULL; 2687 STAILQ_FOREACH(elm, objlist, link) { 2688 if (donelist_check(dlp, elm->obj)) 2689 continue; 2690 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2691 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2692 def = symp; 2693 defobj = elm->obj; 2694 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2695 break; 2696 } 2697 } 2698 } 2699 if (def != NULL) 2700 *defobj_out = defobj; 2701 return def; 2702 } 2703 2704 /* 2705 * Search the symbol table of a shared object and all objects needed 2706 * by it for a symbol of the given name. Search order is 2707 * breadth-first. Returns a pointer to the symbol, or NULL if no 2708 * definition was found. 2709 */ 2710 static const Elf_Sym * 2711 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2712 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2713 DoneList *dlp) 2714 { 2715 const Elf_Sym *def, *def_w; 2716 const Needed_Entry *n; 2717 const Obj_Entry *obj, *defobj, *defobj1; 2718 2719 def = def_w = NULL; 2720 defobj = NULL; 2721 for (n = needed; n != NULL; n = n->next) { 2722 if ((obj = n->obj) == NULL || 2723 donelist_check(dlp, obj) || 2724 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2725 continue; 2726 defobj = obj; 2727 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2728 *defobj_out = defobj; 2729 return (def); 2730 } 2731 } 2732 /* 2733 * There we come when either symbol definition is not found in 2734 * directly needed objects, or found symbol is weak. 2735 */ 2736 for (n = needed; n != NULL; n = n->next) { 2737 if ((obj = n->obj) == NULL) 2738 continue; 2739 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2740 ventry, flags, dlp); 2741 if (def_w == NULL) 2742 continue; 2743 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2744 def = def_w; 2745 defobj = defobj1; 2746 } 2747 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2748 break; 2749 } 2750 if (def != NULL) 2751 *defobj_out = defobj; 2752 return (def); 2753 } 2754 2755 /* 2756 * Search the symbol table of a single shared object for a symbol of 2757 * the given name and version, if requested. Returns a pointer to the 2758 * symbol, or NULL if no definition was found. 2759 * 2760 * The symbol's hash value is passed in for efficiency reasons; that 2761 * eliminates many recomputations of the hash value. 2762 */ 2763 const Elf_Sym * 2764 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2765 const Ver_Entry *ventry, int flags) 2766 { 2767 unsigned long symnum; 2768 const Elf_Sym *vsymp; 2769 Elf_Versym verndx; 2770 int vcount; 2771 2772 if (obj->buckets == NULL) 2773 return NULL; 2774 2775 vsymp = NULL; 2776 vcount = 0; 2777 symnum = obj->buckets[hash % obj->nbuckets]; 2778 2779 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2780 const Elf_Sym *symp; 2781 const char *strp; 2782 2783 if (symnum >= obj->nchains) 2784 return NULL; /* Bad object */ 2785 2786 symp = obj->symtab + symnum; 2787 strp = obj->strtab + symp->st_name; 2788 2789 switch (ELF_ST_TYPE(symp->st_info)) { 2790 case STT_FUNC: 2791 case STT_NOTYPE: 2792 case STT_OBJECT: 2793 if (symp->st_value == 0) 2794 continue; 2795 /* fallthrough */ 2796 case STT_TLS: 2797 if (symp->st_shndx != SHN_UNDEF) 2798 break; 2799 #ifndef __mips__ 2800 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2801 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2802 break; 2803 /* fallthrough */ 2804 #endif 2805 default: 2806 continue; 2807 } 2808 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2809 continue; 2810 2811 if (ventry == NULL) { 2812 if (obj->versyms != NULL) { 2813 verndx = VER_NDX(obj->versyms[symnum]); 2814 if (verndx > obj->vernum) { 2815 _rtld_error("%s: symbol %s references wrong version %d", 2816 obj->path, obj->strtab + symnum, verndx); 2817 continue; 2818 } 2819 /* 2820 * If we are not called from dlsym (i.e. this is a normal 2821 * relocation from unversioned binary, accept the symbol 2822 * immediately if it happens to have first version after 2823 * this shared object became versioned. Otherwise, if 2824 * symbol is versioned and not hidden, remember it. If it 2825 * is the only symbol with this name exported by the 2826 * shared object, it will be returned as a match at the 2827 * end of the function. If symbol is global (verndx < 2) 2828 * accept it unconditionally. 2829 */ 2830 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2831 return symp; 2832 else if (verndx >= VER_NDX_GIVEN) { 2833 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2834 if (vsymp == NULL) 2835 vsymp = symp; 2836 vcount ++; 2837 } 2838 continue; 2839 } 2840 } 2841 return symp; 2842 } else { 2843 if (obj->versyms == NULL) { 2844 if (object_match_name(obj, ventry->name)) { 2845 _rtld_error("%s: object %s should provide version %s for " 2846 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2847 obj->strtab + symnum); 2848 continue; 2849 } 2850 } else { 2851 verndx = VER_NDX(obj->versyms[symnum]); 2852 if (verndx > obj->vernum) { 2853 _rtld_error("%s: symbol %s references wrong version %d", 2854 obj->path, obj->strtab + symnum, verndx); 2855 continue; 2856 } 2857 if (obj->vertab[verndx].hash != ventry->hash || 2858 strcmp(obj->vertab[verndx].name, ventry->name)) { 2859 /* 2860 * Version does not match. Look if this is a global symbol 2861 * and if it is not hidden. If global symbol (verndx < 2) 2862 * is available, use it. Do not return symbol if we are 2863 * called by dlvsym, because dlvsym looks for a specific 2864 * version and default one is not what dlvsym wants. 2865 */ 2866 if ((flags & SYMLOOK_DLSYM) || 2867 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2868 (verndx >= VER_NDX_GIVEN)) 2869 continue; 2870 } 2871 } 2872 return symp; 2873 } 2874 } 2875 return (vcount == 1) ? vsymp : NULL; 2876 } 2877 2878 static void 2879 trace_loaded_objects(Obj_Entry *obj) 2880 { 2881 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2882 int c; 2883 2884 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2885 main_local = ""; 2886 2887 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2888 fmt1 = "\t%o => %p (%x)\n"; 2889 2890 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2891 fmt2 = "\t%o (%x)\n"; 2892 2893 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2894 2895 for (; obj; obj = obj->next) { 2896 Needed_Entry *needed; 2897 char *name, *path; 2898 bool is_lib; 2899 2900 if (list_containers && obj->needed != NULL) 2901 printf("%s:\n", obj->path); 2902 for (needed = obj->needed; needed; needed = needed->next) { 2903 if (needed->obj != NULL) { 2904 if (needed->obj->traced && !list_containers) 2905 continue; 2906 needed->obj->traced = true; 2907 path = needed->obj->path; 2908 } else 2909 path = "not found"; 2910 2911 name = (char *)obj->strtab + needed->name; 2912 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2913 2914 fmt = is_lib ? fmt1 : fmt2; 2915 while ((c = *fmt++) != '\0') { 2916 switch (c) { 2917 default: 2918 putchar(c); 2919 continue; 2920 case '\\': 2921 switch (c = *fmt) { 2922 case '\0': 2923 continue; 2924 case 'n': 2925 putchar('\n'); 2926 break; 2927 case 't': 2928 putchar('\t'); 2929 break; 2930 } 2931 break; 2932 case '%': 2933 switch (c = *fmt) { 2934 case '\0': 2935 continue; 2936 case '%': 2937 default: 2938 putchar(c); 2939 break; 2940 case 'A': 2941 printf("%s", main_local); 2942 break; 2943 case 'a': 2944 printf("%s", obj_main->path); 2945 break; 2946 case 'o': 2947 printf("%s", name); 2948 break; 2949 #if 0 2950 case 'm': 2951 printf("%d", sodp->sod_major); 2952 break; 2953 case 'n': 2954 printf("%d", sodp->sod_minor); 2955 break; 2956 #endif 2957 case 'p': 2958 printf("%s", path); 2959 break; 2960 case 'x': 2961 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2962 break; 2963 } 2964 break; 2965 } 2966 ++fmt; 2967 } 2968 } 2969 } 2970 } 2971 2972 /* 2973 * Unload a dlopened object and its dependencies from memory and from 2974 * our data structures. It is assumed that the DAG rooted in the 2975 * object has already been unreferenced, and that the object has a 2976 * reference count of 0. 2977 */ 2978 static void 2979 unload_object(Obj_Entry *root) 2980 { 2981 Obj_Entry *obj; 2982 Obj_Entry **linkp; 2983 2984 assert(root->refcount == 0); 2985 2986 /* 2987 * Pass over the DAG removing unreferenced objects from 2988 * appropriate lists. 2989 */ 2990 unlink_object(root); 2991 2992 /* Unmap all objects that are no longer referenced. */ 2993 linkp = &obj_list->next; 2994 while ((obj = *linkp) != NULL) { 2995 if (obj->refcount == 0) { 2996 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2997 obj->path); 2998 dbg("unloading \"%s\"", obj->path); 2999 munmap(obj->mapbase, obj->mapsize); 3000 linkmap_delete(obj); 3001 *linkp = obj->next; 3002 obj_count--; 3003 obj_free(obj); 3004 } else 3005 linkp = &obj->next; 3006 } 3007 obj_tail = linkp; 3008 } 3009 3010 static void 3011 unlink_object(Obj_Entry *root) 3012 { 3013 Objlist_Entry *elm; 3014 3015 if (root->refcount == 0) { 3016 /* Remove the object from the RTLD_GLOBAL list. */ 3017 objlist_remove(&list_global, root); 3018 3019 /* Remove the object from all objects' DAG lists. */ 3020 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3021 objlist_remove(&elm->obj->dldags, root); 3022 if (elm->obj != root) 3023 unlink_object(elm->obj); 3024 } 3025 } 3026 } 3027 3028 static void 3029 ref_dag(Obj_Entry *root) 3030 { 3031 Objlist_Entry *elm; 3032 3033 STAILQ_FOREACH(elm, &root->dagmembers, link) 3034 elm->obj->refcount++; 3035 } 3036 3037 static void 3038 unref_dag(Obj_Entry *root) 3039 { 3040 Objlist_Entry *elm; 3041 3042 STAILQ_FOREACH(elm, &root->dagmembers, link) 3043 elm->obj->refcount--; 3044 } 3045 3046 /* 3047 * Common code for MD __tls_get_addr(). 3048 */ 3049 void * 3050 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3051 { 3052 Elf_Addr* dtv = *dtvp; 3053 int lockstate; 3054 3055 /* Check dtv generation in case new modules have arrived */ 3056 if (dtv[0] != tls_dtv_generation) { 3057 Elf_Addr* newdtv; 3058 int to_copy; 3059 3060 lockstate = wlock_acquire(rtld_bind_lock); 3061 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3062 to_copy = dtv[1]; 3063 if (to_copy > tls_max_index) 3064 to_copy = tls_max_index; 3065 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3066 newdtv[0] = tls_dtv_generation; 3067 newdtv[1] = tls_max_index; 3068 free(dtv); 3069 wlock_release(rtld_bind_lock, lockstate); 3070 *dtvp = newdtv; 3071 } 3072 3073 /* Dynamically allocate module TLS if necessary */ 3074 if (!dtv[index + 1]) { 3075 /* Signal safe, wlock will block out signals. */ 3076 lockstate = wlock_acquire(rtld_bind_lock); 3077 if (!dtv[index + 1]) 3078 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3079 wlock_release(rtld_bind_lock, lockstate); 3080 } 3081 return (void*) (dtv[index + 1] + offset); 3082 } 3083 3084 /* XXX not sure what variants to use for arm. */ 3085 3086 #if defined(__ia64__) || defined(__powerpc__) 3087 3088 /* 3089 * Allocate Static TLS using the Variant I method. 3090 */ 3091 void * 3092 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3093 { 3094 Obj_Entry *obj; 3095 char *tcb; 3096 Elf_Addr **tls; 3097 Elf_Addr *dtv; 3098 Elf_Addr addr; 3099 int i; 3100 3101 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3102 return (oldtcb); 3103 3104 assert(tcbsize >= TLS_TCB_SIZE); 3105 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3106 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3107 3108 if (oldtcb != NULL) { 3109 memcpy(tls, oldtcb, tls_static_space); 3110 free(oldtcb); 3111 3112 /* Adjust the DTV. */ 3113 dtv = tls[0]; 3114 for (i = 0; i < dtv[1]; i++) { 3115 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3116 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3117 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3118 } 3119 } 3120 } else { 3121 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3122 tls[0] = dtv; 3123 dtv[0] = tls_dtv_generation; 3124 dtv[1] = tls_max_index; 3125 3126 for (obj = objs; obj; obj = obj->next) { 3127 if (obj->tlsoffset) { 3128 addr = (Elf_Addr)tls + obj->tlsoffset; 3129 memset((void*) (addr + obj->tlsinitsize), 3130 0, obj->tlssize - obj->tlsinitsize); 3131 if (obj->tlsinit) 3132 memcpy((void*) addr, obj->tlsinit, 3133 obj->tlsinitsize); 3134 dtv[obj->tlsindex + 1] = addr; 3135 } 3136 } 3137 } 3138 3139 return (tcb); 3140 } 3141 3142 void 3143 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3144 { 3145 Elf_Addr *dtv; 3146 Elf_Addr tlsstart, tlsend; 3147 int dtvsize, i; 3148 3149 assert(tcbsize >= TLS_TCB_SIZE); 3150 3151 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3152 tlsend = tlsstart + tls_static_space; 3153 3154 dtv = *(Elf_Addr **)tlsstart; 3155 dtvsize = dtv[1]; 3156 for (i = 0; i < dtvsize; i++) { 3157 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3158 free((void*)dtv[i+2]); 3159 } 3160 } 3161 free(dtv); 3162 free(tcb); 3163 } 3164 3165 #endif 3166 3167 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3168 defined(__arm__) || defined(__mips__) 3169 3170 /* 3171 * Allocate Static TLS using the Variant II method. 3172 */ 3173 void * 3174 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3175 { 3176 Obj_Entry *obj; 3177 size_t size; 3178 char *tls; 3179 Elf_Addr *dtv, *olddtv; 3180 Elf_Addr segbase, oldsegbase, addr; 3181 int i; 3182 3183 size = round(tls_static_space, tcbalign); 3184 3185 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3186 tls = calloc(1, size + tcbsize); 3187 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3188 3189 segbase = (Elf_Addr)(tls + size); 3190 ((Elf_Addr*)segbase)[0] = segbase; 3191 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3192 3193 dtv[0] = tls_dtv_generation; 3194 dtv[1] = tls_max_index; 3195 3196 if (oldtls) { 3197 /* 3198 * Copy the static TLS block over whole. 3199 */ 3200 oldsegbase = (Elf_Addr) oldtls; 3201 memcpy((void *)(segbase - tls_static_space), 3202 (const void *)(oldsegbase - tls_static_space), 3203 tls_static_space); 3204 3205 /* 3206 * If any dynamic TLS blocks have been created tls_get_addr(), 3207 * move them over. 3208 */ 3209 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3210 for (i = 0; i < olddtv[1]; i++) { 3211 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3212 dtv[i+2] = olddtv[i+2]; 3213 olddtv[i+2] = 0; 3214 } 3215 } 3216 3217 /* 3218 * We assume that this block was the one we created with 3219 * allocate_initial_tls(). 3220 */ 3221 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3222 } else { 3223 for (obj = objs; obj; obj = obj->next) { 3224 if (obj->tlsoffset) { 3225 addr = segbase - obj->tlsoffset; 3226 memset((void*) (addr + obj->tlsinitsize), 3227 0, obj->tlssize - obj->tlsinitsize); 3228 if (obj->tlsinit) 3229 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3230 dtv[obj->tlsindex + 1] = addr; 3231 } 3232 } 3233 } 3234 3235 return (void*) segbase; 3236 } 3237 3238 void 3239 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3240 { 3241 size_t size; 3242 Elf_Addr* dtv; 3243 int dtvsize, i; 3244 Elf_Addr tlsstart, tlsend; 3245 3246 /* 3247 * Figure out the size of the initial TLS block so that we can 3248 * find stuff which ___tls_get_addr() allocated dynamically. 3249 */ 3250 size = round(tls_static_space, tcbalign); 3251 3252 dtv = ((Elf_Addr**)tls)[1]; 3253 dtvsize = dtv[1]; 3254 tlsend = (Elf_Addr) tls; 3255 tlsstart = tlsend - size; 3256 for (i = 0; i < dtvsize; i++) { 3257 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3258 free((void*) dtv[i+2]); 3259 } 3260 } 3261 3262 free((void*) tlsstart); 3263 free((void*) dtv); 3264 } 3265 3266 #endif 3267 3268 /* 3269 * Allocate TLS block for module with given index. 3270 */ 3271 void * 3272 allocate_module_tls(int index) 3273 { 3274 Obj_Entry* obj; 3275 char* p; 3276 3277 for (obj = obj_list; obj; obj = obj->next) { 3278 if (obj->tlsindex == index) 3279 break; 3280 } 3281 if (!obj) { 3282 _rtld_error("Can't find module with TLS index %d", index); 3283 die(); 3284 } 3285 3286 p = malloc(obj->tlssize); 3287 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3288 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3289 3290 return p; 3291 } 3292 3293 bool 3294 allocate_tls_offset(Obj_Entry *obj) 3295 { 3296 size_t off; 3297 3298 if (obj->tls_done) 3299 return true; 3300 3301 if (obj->tlssize == 0) { 3302 obj->tls_done = true; 3303 return true; 3304 } 3305 3306 if (obj->tlsindex == 1) 3307 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3308 else 3309 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3310 obj->tlssize, obj->tlsalign); 3311 3312 /* 3313 * If we have already fixed the size of the static TLS block, we 3314 * must stay within that size. When allocating the static TLS, we 3315 * leave a small amount of space spare to be used for dynamically 3316 * loading modules which use static TLS. 3317 */ 3318 if (tls_static_space) { 3319 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3320 return false; 3321 } 3322 3323 tls_last_offset = obj->tlsoffset = off; 3324 tls_last_size = obj->tlssize; 3325 obj->tls_done = true; 3326 3327 return true; 3328 } 3329 3330 void 3331 free_tls_offset(Obj_Entry *obj) 3332 { 3333 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3334 defined(__arm__) || defined(__mips__) 3335 /* 3336 * If we were the last thing to allocate out of the static TLS 3337 * block, we give our space back to the 'allocator'. This is a 3338 * simplistic workaround to allow libGL.so.1 to be loaded and 3339 * unloaded multiple times. We only handle the Variant II 3340 * mechanism for now - this really needs a proper allocator. 3341 */ 3342 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3343 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3344 tls_last_offset -= obj->tlssize; 3345 tls_last_size = 0; 3346 } 3347 #endif 3348 } 3349 3350 void * 3351 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3352 { 3353 void *ret; 3354 int lockstate; 3355 3356 lockstate = wlock_acquire(rtld_bind_lock); 3357 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3358 wlock_release(rtld_bind_lock, lockstate); 3359 return (ret); 3360 } 3361 3362 void 3363 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3364 { 3365 int lockstate; 3366 3367 lockstate = wlock_acquire(rtld_bind_lock); 3368 free_tls(tcb, tcbsize, tcbalign); 3369 wlock_release(rtld_bind_lock, lockstate); 3370 } 3371 3372 static void 3373 object_add_name(Obj_Entry *obj, const char *name) 3374 { 3375 Name_Entry *entry; 3376 size_t len; 3377 3378 len = strlen(name); 3379 entry = malloc(sizeof(Name_Entry) + len); 3380 3381 if (entry != NULL) { 3382 strcpy(entry->name, name); 3383 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3384 } 3385 } 3386 3387 static int 3388 object_match_name(const Obj_Entry *obj, const char *name) 3389 { 3390 Name_Entry *entry; 3391 3392 STAILQ_FOREACH(entry, &obj->names, link) { 3393 if (strcmp(name, entry->name) == 0) 3394 return (1); 3395 } 3396 return (0); 3397 } 3398 3399 static Obj_Entry * 3400 locate_dependency(const Obj_Entry *obj, const char *name) 3401 { 3402 const Objlist_Entry *entry; 3403 const Needed_Entry *needed; 3404 3405 STAILQ_FOREACH(entry, &list_main, link) { 3406 if (object_match_name(entry->obj, name)) 3407 return entry->obj; 3408 } 3409 3410 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3411 if (needed->obj == NULL) 3412 continue; 3413 if (object_match_name(needed->obj, name)) 3414 return needed->obj; 3415 } 3416 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3417 obj->path, name); 3418 die(); 3419 } 3420 3421 static int 3422 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3423 const Elf_Vernaux *vna) 3424 { 3425 const Elf_Verdef *vd; 3426 const char *vername; 3427 3428 vername = refobj->strtab + vna->vna_name; 3429 vd = depobj->verdef; 3430 if (vd == NULL) { 3431 _rtld_error("%s: version %s required by %s not defined", 3432 depobj->path, vername, refobj->path); 3433 return (-1); 3434 } 3435 for (;;) { 3436 if (vd->vd_version != VER_DEF_CURRENT) { 3437 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3438 depobj->path, vd->vd_version); 3439 return (-1); 3440 } 3441 if (vna->vna_hash == vd->vd_hash) { 3442 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3443 ((char *)vd + vd->vd_aux); 3444 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3445 return (0); 3446 } 3447 if (vd->vd_next == 0) 3448 break; 3449 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3450 } 3451 if (vna->vna_flags & VER_FLG_WEAK) 3452 return (0); 3453 _rtld_error("%s: version %s required by %s not found", 3454 depobj->path, vername, refobj->path); 3455 return (-1); 3456 } 3457 3458 static int 3459 rtld_verify_object_versions(Obj_Entry *obj) 3460 { 3461 const Elf_Verneed *vn; 3462 const Elf_Verdef *vd; 3463 const Elf_Verdaux *vda; 3464 const Elf_Vernaux *vna; 3465 const Obj_Entry *depobj; 3466 int maxvernum, vernum; 3467 3468 maxvernum = 0; 3469 /* 3470 * Walk over defined and required version records and figure out 3471 * max index used by any of them. Do very basic sanity checking 3472 * while there. 3473 */ 3474 vn = obj->verneed; 3475 while (vn != NULL) { 3476 if (vn->vn_version != VER_NEED_CURRENT) { 3477 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3478 obj->path, vn->vn_version); 3479 return (-1); 3480 } 3481 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3482 for (;;) { 3483 vernum = VER_NEED_IDX(vna->vna_other); 3484 if (vernum > maxvernum) 3485 maxvernum = vernum; 3486 if (vna->vna_next == 0) 3487 break; 3488 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3489 } 3490 if (vn->vn_next == 0) 3491 break; 3492 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3493 } 3494 3495 vd = obj->verdef; 3496 while (vd != NULL) { 3497 if (vd->vd_version != VER_DEF_CURRENT) { 3498 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3499 obj->path, vd->vd_version); 3500 return (-1); 3501 } 3502 vernum = VER_DEF_IDX(vd->vd_ndx); 3503 if (vernum > maxvernum) 3504 maxvernum = vernum; 3505 if (vd->vd_next == 0) 3506 break; 3507 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3508 } 3509 3510 if (maxvernum == 0) 3511 return (0); 3512 3513 /* 3514 * Store version information in array indexable by version index. 3515 * Verify that object version requirements are satisfied along the 3516 * way. 3517 */ 3518 obj->vernum = maxvernum + 1; 3519 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3520 3521 vd = obj->verdef; 3522 while (vd != NULL) { 3523 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3524 vernum = VER_DEF_IDX(vd->vd_ndx); 3525 assert(vernum <= maxvernum); 3526 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3527 obj->vertab[vernum].hash = vd->vd_hash; 3528 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3529 obj->vertab[vernum].file = NULL; 3530 obj->vertab[vernum].flags = 0; 3531 } 3532 if (vd->vd_next == 0) 3533 break; 3534 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3535 } 3536 3537 vn = obj->verneed; 3538 while (vn != NULL) { 3539 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3540 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3541 for (;;) { 3542 if (check_object_provided_version(obj, depobj, vna)) 3543 return (-1); 3544 vernum = VER_NEED_IDX(vna->vna_other); 3545 assert(vernum <= maxvernum); 3546 obj->vertab[vernum].hash = vna->vna_hash; 3547 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3548 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3549 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3550 VER_INFO_HIDDEN : 0; 3551 if (vna->vna_next == 0) 3552 break; 3553 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3554 } 3555 if (vn->vn_next == 0) 3556 break; 3557 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3558 } 3559 return 0; 3560 } 3561 3562 static int 3563 rtld_verify_versions(const Objlist *objlist) 3564 { 3565 Objlist_Entry *entry; 3566 int rc; 3567 3568 rc = 0; 3569 STAILQ_FOREACH(entry, objlist, link) { 3570 /* 3571 * Skip dummy objects or objects that have their version requirements 3572 * already checked. 3573 */ 3574 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3575 continue; 3576 if (rtld_verify_object_versions(entry->obj) == -1) { 3577 rc = -1; 3578 if (ld_tracing == NULL) 3579 break; 3580 } 3581 } 3582 if (rc == 0 || ld_tracing != NULL) 3583 rc = rtld_verify_object_versions(&obj_rtld); 3584 return rc; 3585 } 3586 3587 const Ver_Entry * 3588 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3589 { 3590 Elf_Versym vernum; 3591 3592 if (obj->vertab) { 3593 vernum = VER_NDX(obj->versyms[symnum]); 3594 if (vernum >= obj->vernum) { 3595 _rtld_error("%s: symbol %s has wrong verneed value %d", 3596 obj->path, obj->strtab + symnum, vernum); 3597 } else if (obj->vertab[vernum].hash != 0) { 3598 return &obj->vertab[vernum]; 3599 } 3600 } 3601 return NULL; 3602 } 3603