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