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: src/libexec/rtld-elf/rtld.c,v 1.43.2.15 2003/02/20 20:42:46 kan Exp $ 27 * $DragonFly: src/libexec/rtld-elf/rtld.c,v 1.29 2008/01/08 00:02:04 corecode Exp $ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/resident.h> 44 #include <sys/tls.h> 45 46 #include <machine/tls.h> 47 48 #include <dlfcn.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <stdarg.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 #include "debug.h" 59 #include "rtld.h" 60 61 #define PATH_RTLD "/usr/libexec/ld-elf.so.2" 62 #define LD_ARY_CACHE 16 63 64 /* Types. */ 65 typedef void (*func_ptr_type)(); 66 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 67 68 /* 69 * This structure provides a reentrant way to keep a list of objects and 70 * check which ones have already been processed in some way. 71 */ 72 typedef struct Struct_DoneList { 73 const Obj_Entry **objs; /* Array of object pointers */ 74 unsigned int num_alloc; /* Allocated size of the array */ 75 unsigned int num_used; /* Number of array slots used */ 76 } DoneList; 77 78 /* 79 * Function declarations. 80 */ 81 static void die(void); 82 static void digest_dynamic(Obj_Entry *, int); 83 static const char *_getenv_ld(const char *id); 84 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 85 static Obj_Entry *dlcheck(void *); 86 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 87 static bool donelist_check(DoneList *, const Obj_Entry *); 88 static void errmsg_restore(char *); 89 static char *errmsg_save(void); 90 static void *fill_search_info(const char *, size_t, void *); 91 static char *find_library(const char *, const Obj_Entry *); 92 static Obj_Entry *find_object(const char *); 93 static Obj_Entry *find_object2(const char *, int *, struct stat *); 94 static const char *gethints(void); 95 static void init_dag(Obj_Entry *); 96 static void init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *); 97 static void init_rtld(caddr_t); 98 static void initlist_add_neededs(Needed_Entry *needed, Objlist *list); 99 static void initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, 100 Objlist *list); 101 static bool is_exported(const Elf_Sym *); 102 static void linkmap_add(Obj_Entry *); 103 static void linkmap_delete(Obj_Entry *); 104 static int load_needed_objects(Obj_Entry *); 105 static int load_preload_objects(void); 106 static Obj_Entry *load_object(char *); 107 static void lock_check(void); 108 static Obj_Entry *obj_from_addr(const void *); 109 static void objlist_call_fini(Objlist *); 110 static void objlist_call_init(Objlist *); 111 static void objlist_clear(Objlist *); 112 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 113 static void objlist_init(Objlist *); 114 static void objlist_push_head(Objlist *, Obj_Entry *); 115 static void objlist_push_tail(Objlist *, Obj_Entry *); 116 static void objlist_remove(Objlist *, Obj_Entry *); 117 static void objlist_remove_unref(Objlist *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 120 static int rtld_dirname(const char *, char *); 121 static void rtld_exit(void); 122 static char *search_library_path(const char *, const char *); 123 static const void **get_program_var_addr(const char *name); 124 static void set_program_var(const char *, const void *); 125 static const Elf_Sym *symlook_default(const char *, unsigned long hash, 126 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt); 127 static const Elf_Sym *symlook_list(const char *, unsigned long, 128 const Objlist *, const Obj_Entry **, bool in_plt, DoneList *); 129 static const Elf_Sym *symlook_needed(const char *, unsigned long, 130 const Needed_Entry *, const Obj_Entry **, bool in_plt, DoneList *); 131 static void trace_loaded_objects(Obj_Entry *obj); 132 static void unlink_object(Obj_Entry *); 133 static void unload_object(Obj_Entry *); 134 static void unref_dag(Obj_Entry *); 135 136 void r_debug_state(struct r_debug*, struct link_map*); 137 138 /* 139 * Data declarations. 140 */ 141 static char *error_message; /* Message for dlerror(), or NULL */ 142 struct r_debug r_debug; /* for GDB; */ 143 static bool trust; /* False for setuid and setgid programs */ 144 static const char *ld_bind_now; /* Environment variable for immediate binding */ 145 static const char *ld_debug; /* Environment variable for debugging */ 146 static const char *ld_library_path; /* Environment variable for search path */ 147 static char *ld_preload; /* Environment variable for libraries to 148 load first */ 149 static const char *ld_tracing; /* Called from ldd(1) to print libs */ 150 /* Optional function call tracing hook */ 151 static int (*rtld_functrace)(const char *caller_obj, 152 const char *callee_obj, 153 const char *callee_func, 154 void *stack); 155 static Obj_Entry *rtld_functrace_obj; /* Object thereof */ 156 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 157 static Obj_Entry **obj_tail; /* Link field of last object in list */ 158 static Obj_Entry **preload_tail; 159 static Obj_Entry *obj_main; /* The main program shared object */ 160 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 161 static unsigned int obj_count; /* Number of objects in obj_list */ 162 static int ld_resident; /* Non-zero if resident */ 163 static const char *ld_ary[LD_ARY_CACHE]; 164 static int ld_index; 165 static Objlist initlist; 166 167 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 168 STAILQ_HEAD_INITIALIZER(list_global); 169 static Objlist list_main = /* Objects loaded at program startup */ 170 STAILQ_HEAD_INITIALIZER(list_main); 171 static Objlist list_fini = /* Objects needing fini() calls */ 172 STAILQ_HEAD_INITIALIZER(list_fini); 173 174 static LockInfo lockinfo; 175 176 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 177 178 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 179 180 extern Elf_Dyn _DYNAMIC; 181 #pragma weak _DYNAMIC 182 183 /* 184 * These are the functions the dynamic linker exports to application 185 * programs. They are the only symbols the dynamic linker is willing 186 * to export from itself. 187 */ 188 static func_ptr_type exports[] = { 189 (func_ptr_type) &_rtld_error, 190 (func_ptr_type) &dlclose, 191 (func_ptr_type) &dlerror, 192 (func_ptr_type) &dlopen, 193 (func_ptr_type) &dlsym, 194 (func_ptr_type) &dladdr, 195 (func_ptr_type) &dlinfo, 196 #ifdef __i386__ 197 (func_ptr_type) &___tls_get_addr, 198 #endif 199 (func_ptr_type) &__tls_get_addr, 200 (func_ptr_type) &__tls_get_addr_tcb, 201 (func_ptr_type) &_rtld_allocate_tls, 202 (func_ptr_type) &_rtld_free_tls, 203 (func_ptr_type) &_rtld_call_init, 204 NULL 205 }; 206 207 /* 208 * Global declarations normally provided by crt1. The dynamic linker is 209 * not built with crt1, so we have to provide them ourselves. 210 */ 211 char *__progname; 212 char **environ; 213 214 /* 215 * Globals to control TLS allocation. 216 */ 217 size_t tls_last_offset; /* Static TLS offset of last module */ 218 size_t tls_last_size; /* Static TLS size of last module */ 219 size_t tls_static_space; /* Static TLS space allocated */ 220 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 221 int tls_max_index = 1; /* Largest module index allocated */ 222 223 /* 224 * Fill in a DoneList with an allocation large enough to hold all of 225 * the currently-loaded objects. Keep this as a macro since it calls 226 * alloca and we want that to occur within the scope of the caller. 227 */ 228 #define donelist_init(dlp) \ 229 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 230 assert((dlp)->objs != NULL), \ 231 (dlp)->num_alloc = obj_count, \ 232 (dlp)->num_used = 0) 233 234 static __inline void 235 rlock_acquire(void) 236 { 237 lockinfo.rlock_acquire(lockinfo.thelock); 238 atomic_incr_int(&lockinfo.rcount); 239 lock_check(); 240 } 241 242 static __inline void 243 wlock_acquire(void) 244 { 245 lockinfo.wlock_acquire(lockinfo.thelock); 246 atomic_incr_int(&lockinfo.wcount); 247 lock_check(); 248 } 249 250 static __inline void 251 rlock_release(void) 252 { 253 atomic_decr_int(&lockinfo.rcount); 254 lockinfo.rlock_release(lockinfo.thelock); 255 } 256 257 static __inline void 258 wlock_release(void) 259 { 260 atomic_decr_int(&lockinfo.wcount); 261 lockinfo.wlock_release(lockinfo.thelock); 262 } 263 264 /* 265 * Main entry point for dynamic linking. The first argument is the 266 * stack pointer. The stack is expected to be laid out as described 267 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 268 * Specifically, the stack pointer points to a word containing 269 * ARGC. Following that in the stack is a null-terminated sequence 270 * of pointers to argument strings. Then comes a null-terminated 271 * sequence of pointers to environment strings. Finally, there is a 272 * sequence of "auxiliary vector" entries. 273 * 274 * The second argument points to a place to store the dynamic linker's 275 * exit procedure pointer and the third to a place to store the main 276 * program's object. 277 * 278 * The return value is the main program's entry point. 279 */ 280 281 func_ptr_type 282 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 283 { 284 Elf_Auxinfo *aux_info[AT_COUNT]; 285 int i; 286 int argc; 287 char **argv; 288 char **env; 289 Elf_Auxinfo *aux; 290 Elf_Auxinfo *auxp; 291 const char *argv0; 292 Objlist_Entry *entry; 293 Obj_Entry *obj; 294 295 ld_index = 0; /* don't use old env cache in case we are resident */ 296 297 /* 298 * On entry, the dynamic linker itself has not been relocated yet. 299 * Be very careful not to reference any global data until after 300 * init_rtld has returned. It is OK to reference file-scope statics 301 * and string constants, and to call static and global functions. 302 */ 303 304 /* Find the auxiliary vector on the stack. */ 305 argc = *sp++; 306 argv = (char **) sp; 307 sp += argc + 1; /* Skip over arguments and NULL terminator */ 308 env = (char **) sp; 309 310 /* 311 * If we aren't already resident we have to dig out some more info. 312 * Note that auxinfo does not exist when we are resident. 313 */ 314 if (ld_resident == 0) { 315 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 316 ; 317 aux = (Elf_Auxinfo *) sp; 318 319 /* Digest the auxiliary vector. */ 320 for (i = 0; i < AT_COUNT; i++) 321 aux_info[i] = NULL; 322 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 323 if (auxp->a_type < AT_COUNT) 324 aux_info[auxp->a_type] = auxp; 325 } 326 327 /* Initialize and relocate ourselves. */ 328 assert(aux_info[AT_BASE] != NULL); 329 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 330 } 331 332 __progname = obj_rtld.path; 333 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 334 environ = env; 335 336 trust = (geteuid() == getuid()) && (getegid() == getgid()); 337 338 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 339 if (trust) { 340 ld_debug = _getenv_ld("LD_DEBUG"); 341 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 342 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 343 } 344 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 345 346 if (ld_debug != NULL && *ld_debug != '\0') 347 debug = 1; 348 dbg("%s is initialized, base address = %p", __progname, 349 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 350 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 351 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 352 353 /* 354 * If we are resident we can skip work that we have already done. 355 * Note that the stack is reset and there is no Elf_Auxinfo 356 * when running from a resident image, and the static globals setup 357 * between here and resident_skip will have already been setup. 358 */ 359 if (ld_resident) 360 goto resident_skip1; 361 362 /* 363 * Load the main program, or process its program header if it is 364 * already loaded. 365 */ 366 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 367 int fd = aux_info[AT_EXECFD]->a_un.a_val; 368 dbg("loading main program"); 369 obj_main = map_object(fd, argv0, NULL); 370 close(fd); 371 if (obj_main == NULL) 372 die(); 373 } else { /* Main program already loaded. */ 374 const Elf_Phdr *phdr; 375 int phnum; 376 caddr_t entry; 377 378 dbg("processing main program's program header"); 379 assert(aux_info[AT_PHDR] != NULL); 380 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 381 assert(aux_info[AT_PHNUM] != NULL); 382 phnum = aux_info[AT_PHNUM]->a_un.a_val; 383 assert(aux_info[AT_PHENT] != NULL); 384 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 385 assert(aux_info[AT_ENTRY] != NULL); 386 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 387 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 388 die(); 389 } 390 391 obj_main->path = xstrdup(argv0); 392 obj_main->mainprog = true; 393 394 /* 395 * Get the actual dynamic linker pathname from the executable if 396 * possible. (It should always be possible.) That ensures that 397 * gdb will find the right dynamic linker even if a non-standard 398 * one is being used. 399 */ 400 if (obj_main->interp != NULL && 401 strcmp(obj_main->interp, obj_rtld.path) != 0) { 402 free(obj_rtld.path); 403 obj_rtld.path = xstrdup(obj_main->interp); 404 __progname = obj_rtld.path; 405 } 406 407 digest_dynamic(obj_main, 0); 408 409 linkmap_add(obj_main); 410 linkmap_add(&obj_rtld); 411 412 /* Link the main program into the list of objects. */ 413 *obj_tail = obj_main; 414 obj_tail = &obj_main->next; 415 obj_count++; 416 obj_main->refcount++; 417 /* Make sure we don't call the main program's init and fini functions. */ 418 obj_main->init = obj_main->fini = NULL; 419 420 /* Initialize a fake symbol for resolving undefined weak references. */ 421 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 422 sym_zero.st_shndx = SHN_ABS; 423 424 dbg("loading LD_PRELOAD libraries"); 425 if (load_preload_objects() == -1) 426 die(); 427 preload_tail = obj_tail; 428 429 dbg("loading needed objects"); 430 if (load_needed_objects(obj_main) == -1) 431 die(); 432 433 /* Make a list of all objects loaded at startup. */ 434 for (obj = obj_list; obj != NULL; obj = obj->next) 435 objlist_push_tail(&list_main, obj); 436 437 resident_skip1: 438 439 if (ld_tracing) { /* We're done */ 440 trace_loaded_objects(obj_main); 441 exit(0); 442 } 443 444 if (ld_resident) /* XXX clean this up! */ 445 goto resident_skip2; 446 447 if (getenv("LD_DUMP_REL_PRE") != NULL) { 448 dump_relocations(obj_main); 449 exit (0); 450 } 451 452 /* setup TLS for main thread */ 453 dbg("initializing initial thread local storage"); 454 STAILQ_FOREACH(entry, &list_main, link) { 455 /* 456 * Allocate all the initial objects out of the static TLS 457 * block even if they didn't ask for it. 458 */ 459 allocate_tls_offset(entry->obj); 460 } 461 462 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 463 464 /* 465 * Do not try to allocate the TLS here, let libc do it itself. 466 * (crt1 for the program will call _init_tls()) 467 */ 468 469 if (relocate_objects(obj_main, 470 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 471 die(); 472 473 dbg("doing copy relocations"); 474 if (do_copy_relocations(obj_main) == -1) 475 die(); 476 477 resident_skip2: 478 479 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 480 if (exec_sys_unregister(-1) < 0) { 481 dbg("exec_sys_unregister failed %d\n", errno); 482 exit(errno); 483 } 484 dbg("exec_sys_unregister success\n"); 485 exit(0); 486 } 487 488 if (getenv("LD_DUMP_REL_POST") != NULL) { 489 dump_relocations(obj_main); 490 exit (0); 491 } 492 493 dbg("initializing key program variables"); 494 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 495 set_program_var("environ", env); 496 497 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 498 extern void resident_start(void); 499 ld_resident = 1; 500 if (exec_sys_register(resident_start) < 0) { 501 dbg("exec_sys_register failed %d\n", errno); 502 exit(errno); 503 } 504 dbg("exec_sys_register success\n"); 505 exit(0); 506 } 507 508 dbg("initializing thread locks"); 509 lockdflt_init(&lockinfo); 510 lockinfo.thelock = lockinfo.lock_create(lockinfo.context); 511 512 /* Make a list of init functions to call. */ 513 objlist_init(&initlist); 514 initlist_add_objects(obj_list, preload_tail, &initlist); 515 516 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 517 518 /* 519 * Do NOT call the initlist here, give libc a chance to set up 520 * the initial TLS segment. crt1 will then call _rtld_call_init(). 521 */ 522 523 dbg("transferring control to program entry point = %p", obj_main->entry); 524 525 /* Return the exit procedure and the program entry point. */ 526 *exit_proc = rtld_exit; 527 *objp = obj_main; 528 return (func_ptr_type) obj_main->entry; 529 } 530 531 /* 532 * Call the initialization list for dynamically loaded libraries. 533 * (called from crt1.c). 534 */ 535 void 536 _rtld_call_init(void) 537 { 538 objlist_call_init(&initlist); 539 wlock_acquire(); 540 objlist_clear(&initlist); 541 wlock_release(); 542 } 543 544 Elf_Addr 545 _rtld_bind(Obj_Entry *obj, Elf_Word reloff, void *stack) 546 { 547 const Elf_Rel *rel; 548 const Elf_Sym *def; 549 const Obj_Entry *defobj; 550 Elf_Addr *where; 551 Elf_Addr target; 552 int do_reloc = 1; 553 554 rlock_acquire(); 555 if (obj->pltrel) 556 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 557 else 558 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 559 560 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 561 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 562 if (def == NULL) 563 die(); 564 565 target = (Elf_Addr)(defobj->relocbase + def->st_value); 566 567 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 568 defobj->strtab + def->st_name, basename(obj->path), 569 (void *)target, basename(defobj->path)); 570 rlock_release(); 571 572 /* 573 * If we have a function call tracing hook, and the 574 * hook would like to keep tracing this one function, 575 * prevent the relocation so we will wind up here 576 * the next time again. 577 * 578 * We don't want to functrace calls from the functracer 579 * to avoid recursive loops. 580 */ 581 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 582 if (rtld_functrace(obj->path, 583 defobj->path, 584 defobj->strtab + def->st_name, 585 stack)) 586 do_reloc = 0; 587 } 588 589 if (do_reloc) 590 reloc_jmpslot(where, target); 591 return target; 592 } 593 594 /* 595 * Error reporting function. Use it like printf. If formats the message 596 * into a buffer, and sets things up so that the next call to dlerror() 597 * will return the message. 598 */ 599 void 600 _rtld_error(const char *fmt, ...) 601 { 602 static char buf[512]; 603 va_list ap; 604 605 va_start(ap, fmt); 606 vsnprintf(buf, sizeof buf, fmt, ap); 607 error_message = buf; 608 va_end(ap); 609 } 610 611 /* 612 * Return a dynamically-allocated copy of the current error message, if any. 613 */ 614 static char * 615 errmsg_save(void) 616 { 617 return error_message == NULL ? NULL : xstrdup(error_message); 618 } 619 620 /* 621 * Restore the current error message from a copy which was previously saved 622 * by errmsg_save(). The copy is freed. 623 */ 624 static void 625 errmsg_restore(char *saved_msg) 626 { 627 if (saved_msg == NULL) 628 error_message = NULL; 629 else { 630 _rtld_error("%s", saved_msg); 631 free(saved_msg); 632 } 633 } 634 635 const char * 636 basename(const char *name) 637 { 638 const char *p = strrchr(name, '/'); 639 return p != NULL ? p + 1 : name; 640 } 641 642 static void 643 die(void) 644 { 645 const char *msg = dlerror(); 646 647 if (msg == NULL) 648 msg = "Fatal error"; 649 errx(1, "%s", msg); 650 } 651 652 /* 653 * Process a shared object's DYNAMIC section, and save the important 654 * information in its Obj_Entry structure. 655 */ 656 static void 657 digest_dynamic(Obj_Entry *obj, int early) 658 { 659 const Elf_Dyn *dynp; 660 Needed_Entry **needed_tail = &obj->needed; 661 const Elf_Dyn *dyn_rpath = NULL; 662 int plttype = DT_REL; 663 664 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 665 switch (dynp->d_tag) { 666 667 case DT_REL: 668 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 669 break; 670 671 case DT_RELSZ: 672 obj->relsize = dynp->d_un.d_val; 673 break; 674 675 case DT_RELENT: 676 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 677 break; 678 679 case DT_JMPREL: 680 obj->pltrel = (const Elf_Rel *) 681 (obj->relocbase + dynp->d_un.d_ptr); 682 break; 683 684 case DT_PLTRELSZ: 685 obj->pltrelsize = dynp->d_un.d_val; 686 break; 687 688 case DT_RELA: 689 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 690 break; 691 692 case DT_RELASZ: 693 obj->relasize = dynp->d_un.d_val; 694 break; 695 696 case DT_RELAENT: 697 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 698 break; 699 700 case DT_PLTREL: 701 plttype = dynp->d_un.d_val; 702 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 703 break; 704 705 case DT_SYMTAB: 706 obj->symtab = (const Elf_Sym *) 707 (obj->relocbase + dynp->d_un.d_ptr); 708 break; 709 710 case DT_SYMENT: 711 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 712 break; 713 714 case DT_STRTAB: 715 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 716 break; 717 718 case DT_STRSZ: 719 obj->strsize = dynp->d_un.d_val; 720 break; 721 722 case DT_HASH: 723 { 724 const Elf_Addr *hashtab = (const Elf_Addr *) 725 (obj->relocbase + dynp->d_un.d_ptr); 726 obj->nbuckets = hashtab[0]; 727 obj->nchains = hashtab[1]; 728 obj->buckets = hashtab + 2; 729 obj->chains = obj->buckets + obj->nbuckets; 730 } 731 break; 732 733 case DT_NEEDED: 734 if (!obj->rtld) { 735 Needed_Entry *nep = NEW(Needed_Entry); 736 nep->name = dynp->d_un.d_val; 737 nep->obj = NULL; 738 nep->next = NULL; 739 740 *needed_tail = nep; 741 needed_tail = &nep->next; 742 } 743 break; 744 745 case DT_PLTGOT: 746 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 747 break; 748 749 case DT_TEXTREL: 750 obj->textrel = true; 751 break; 752 753 case DT_SYMBOLIC: 754 obj->symbolic = true; 755 break; 756 757 case DT_RPATH: 758 case DT_RUNPATH: /* XXX: process separately */ 759 /* 760 * We have to wait until later to process this, because we 761 * might not have gotten the address of the string table yet. 762 */ 763 dyn_rpath = dynp; 764 break; 765 766 case DT_SONAME: 767 /* Not used by the dynamic linker. */ 768 break; 769 770 case DT_INIT: 771 obj->init = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr); 772 break; 773 774 case DT_FINI: 775 obj->fini = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr); 776 break; 777 778 case DT_DEBUG: 779 /* XXX - not implemented yet */ 780 if (!early) 781 dbg("Filling in DT_DEBUG entry"); 782 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 783 break; 784 785 case DT_FLAGS: 786 if (dynp->d_un.d_val & DF_ORIGIN) { 787 obj->origin_path = xmalloc(PATH_MAX); 788 if (rtld_dirname(obj->path, obj->origin_path) == -1) 789 die(); 790 } 791 if (dynp->d_un.d_val & DF_SYMBOLIC) 792 obj->symbolic = true; 793 if (dynp->d_un.d_val & DF_TEXTREL) 794 obj->textrel = true; 795 if (dynp->d_un.d_val & DF_BIND_NOW) 796 obj->bind_now = true; 797 if (dynp->d_un.d_val & DF_STATIC_TLS) 798 ; 799 break; 800 801 default: 802 if (!early) 803 dbg("Ignoring d_tag %d = %#x", dynp->d_tag, dynp->d_tag); 804 break; 805 } 806 } 807 808 obj->traced = false; 809 810 if (plttype == DT_RELA) { 811 obj->pltrela = (const Elf_Rela *) obj->pltrel; 812 obj->pltrel = NULL; 813 obj->pltrelasize = obj->pltrelsize; 814 obj->pltrelsize = 0; 815 } 816 817 if (dyn_rpath != NULL) 818 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val; 819 } 820 821 /* 822 * Process a shared object's program header. This is used only for the 823 * main program, when the kernel has already loaded the main program 824 * into memory before calling the dynamic linker. It creates and 825 * returns an Obj_Entry structure. 826 */ 827 static Obj_Entry * 828 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 829 { 830 Obj_Entry *obj; 831 const Elf_Phdr *phlimit = phdr + phnum; 832 const Elf_Phdr *ph; 833 int nsegs = 0; 834 835 obj = obj_new(); 836 for (ph = phdr; ph < phlimit; ph++) { 837 switch (ph->p_type) { 838 839 case PT_PHDR: 840 if ((const Elf_Phdr *)ph->p_vaddr != phdr) { 841 _rtld_error("%s: invalid PT_PHDR", path); 842 return NULL; 843 } 844 obj->phdr = (const Elf_Phdr *) ph->p_vaddr; 845 obj->phsize = ph->p_memsz; 846 break; 847 848 case PT_INTERP: 849 obj->interp = (const char *) ph->p_vaddr; 850 break; 851 852 case PT_LOAD: 853 if (nsegs == 0) { /* First load segment */ 854 obj->vaddrbase = trunc_page(ph->p_vaddr); 855 obj->mapbase = (caddr_t) obj->vaddrbase; 856 obj->relocbase = obj->mapbase - obj->vaddrbase; 857 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 858 obj->vaddrbase; 859 } else { /* Last load segment */ 860 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 861 obj->vaddrbase; 862 } 863 nsegs++; 864 break; 865 866 case PT_DYNAMIC: 867 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; 868 break; 869 870 case PT_TLS: 871 obj->tlsindex = 1; 872 obj->tlssize = ph->p_memsz; 873 obj->tlsalign = ph->p_align; 874 obj->tlsinitsize = ph->p_filesz; 875 obj->tlsinit = (void*) ph->p_vaddr; 876 break; 877 } 878 } 879 if (nsegs < 1) { 880 _rtld_error("%s: too few PT_LOAD segments", path); 881 return NULL; 882 } 883 884 obj->entry = entry; 885 return obj; 886 } 887 888 static Obj_Entry * 889 dlcheck(void *handle) 890 { 891 Obj_Entry *obj; 892 893 for (obj = obj_list; obj != NULL; obj = obj->next) 894 if (obj == (Obj_Entry *) handle) 895 break; 896 897 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 898 _rtld_error("Invalid shared object handle %p", handle); 899 return NULL; 900 } 901 return obj; 902 } 903 904 /* 905 * If the given object is already in the donelist, return true. Otherwise 906 * add the object to the list and return false. 907 */ 908 static bool 909 donelist_check(DoneList *dlp, const Obj_Entry *obj) 910 { 911 unsigned int i; 912 913 for (i = 0; i < dlp->num_used; i++) 914 if (dlp->objs[i] == obj) 915 return true; 916 /* 917 * Our donelist allocation should always be sufficient. But if 918 * our threads locking isn't working properly, more shared objects 919 * could have been loaded since we allocated the list. That should 920 * never happen, but we'll handle it properly just in case it does. 921 */ 922 if (dlp->num_used < dlp->num_alloc) 923 dlp->objs[dlp->num_used++] = obj; 924 return false; 925 } 926 927 /* 928 * Hash function for symbol table lookup. Don't even think about changing 929 * this. It is specified by the System V ABI. 930 */ 931 unsigned long 932 elf_hash(const char *name) 933 { 934 const unsigned char *p = (const unsigned char *) name; 935 unsigned long h = 0; 936 unsigned long g; 937 938 while (*p != '\0') { 939 h = (h << 4) + *p++; 940 if ((g = h & 0xf0000000) != 0) 941 h ^= g >> 24; 942 h &= ~g; 943 } 944 return h; 945 } 946 947 /* 948 * Find the library with the given name, and return its full pathname. 949 * The returned string is dynamically allocated. Generates an error 950 * message and returns NULL if the library cannot be found. 951 * 952 * If the second argument is non-NULL, then it refers to an already- 953 * loaded shared object, whose library search path will be searched. 954 * 955 * The search order is: 956 * LD_LIBRARY_PATH 957 * rpath in the referencing file 958 * ldconfig hints 959 * /usr/lib 960 */ 961 static char * 962 find_library(const char *name, const Obj_Entry *refobj) 963 { 964 char *pathname; 965 966 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 967 if (name[0] != '/' && !trust) { 968 _rtld_error("Absolute pathname required for shared object \"%s\"", 969 name); 970 return NULL; 971 } 972 return xstrdup(name); 973 } 974 975 dbg(" Searching for \"%s\"", name); 976 977 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 978 (refobj != NULL && 979 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 980 (pathname = search_library_path(name, gethints())) != NULL || 981 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 982 return pathname; 983 984 if(refobj != NULL && refobj->path != NULL) { 985 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 986 name, basename(refobj->path)); 987 } else { 988 _rtld_error("Shared object \"%s\" not found", name); 989 } 990 return NULL; 991 } 992 993 /* 994 * Given a symbol number in a referencing object, find the corresponding 995 * definition of the symbol. Returns a pointer to the symbol, or NULL if 996 * no definition was found. Returns a pointer to the Obj_Entry of the 997 * defining object via the reference parameter DEFOBJ_OUT. 998 */ 999 const Elf_Sym * 1000 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1001 const Obj_Entry **defobj_out, bool in_plt, SymCache *cache) 1002 { 1003 const Elf_Sym *ref; 1004 const Elf_Sym *def; 1005 const Obj_Entry *defobj; 1006 const char *name; 1007 unsigned long hash; 1008 1009 /* 1010 * If we have already found this symbol, get the information from 1011 * the cache. 1012 */ 1013 if (symnum >= refobj->nchains) 1014 return NULL; /* Bad object */ 1015 if (cache != NULL && cache[symnum].sym != NULL) { 1016 *defobj_out = cache[symnum].obj; 1017 return cache[symnum].sym; 1018 } 1019 1020 ref = refobj->symtab + symnum; 1021 name = refobj->strtab + ref->st_name; 1022 defobj = NULL; 1023 1024 /* 1025 * We don't have to do a full scale lookup if the symbol is local. 1026 * We know it will bind to the instance in this load module; to 1027 * which we already have a pointer (ie ref). By not doing a lookup, 1028 * we not only improve performance, but it also avoids unresolvable 1029 * symbols when local symbols are not in the hash table. 1030 * 1031 * This might occur for TLS module relocations, which simply use 1032 * symbol 0. 1033 */ 1034 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1035 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1036 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1037 symnum); 1038 } 1039 hash = elf_hash(name); 1040 def = symlook_default(name, hash, refobj, &defobj, in_plt); 1041 } else { 1042 def = ref; 1043 defobj = refobj; 1044 } 1045 1046 /* 1047 * If we found no definition and the reference is weak, treat the 1048 * symbol as having the value zero. 1049 */ 1050 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1051 def = &sym_zero; 1052 defobj = obj_main; 1053 } 1054 1055 if (def != NULL) { 1056 *defobj_out = defobj; 1057 /* Record the information in the cache to avoid subsequent lookups. */ 1058 if (cache != NULL) { 1059 cache[symnum].sym = def; 1060 cache[symnum].obj = defobj; 1061 } 1062 } else 1063 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1064 return def; 1065 } 1066 1067 /* 1068 * Return the search path from the ldconfig hints file, reading it if 1069 * necessary. Returns NULL if there are problems with the hints file, 1070 * or if the search path there is empty. 1071 */ 1072 static const char * 1073 gethints(void) 1074 { 1075 static char *hints; 1076 1077 if (hints == NULL) { 1078 int fd; 1079 struct elfhints_hdr hdr; 1080 char *p; 1081 1082 /* Keep from trying again in case the hints file is bad. */ 1083 hints = ""; 1084 1085 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1) 1086 return NULL; 1087 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1088 hdr.magic != ELFHINTS_MAGIC || 1089 hdr.version != 1) { 1090 close(fd); 1091 return NULL; 1092 } 1093 p = xmalloc(hdr.dirlistlen + 1); 1094 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1095 read(fd, p, hdr.dirlistlen + 1) != hdr.dirlistlen + 1) { 1096 free(p); 1097 close(fd); 1098 return NULL; 1099 } 1100 hints = p; 1101 close(fd); 1102 } 1103 return hints[0] != '\0' ? hints : NULL; 1104 } 1105 1106 static void 1107 init_dag(Obj_Entry *root) 1108 { 1109 DoneList donelist; 1110 1111 donelist_init(&donelist); 1112 init_dag1(root, root, &donelist); 1113 } 1114 1115 static void 1116 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1117 { 1118 const Needed_Entry *needed; 1119 1120 if (donelist_check(dlp, obj)) 1121 return; 1122 objlist_push_tail(&obj->dldags, root); 1123 objlist_push_tail(&root->dagmembers, obj); 1124 for (needed = obj->needed; needed != NULL; needed = needed->next) 1125 if (needed->obj != NULL) 1126 init_dag1(root, needed->obj, dlp); 1127 } 1128 1129 /* 1130 * Initialize the dynamic linker. The argument is the address at which 1131 * the dynamic linker has been mapped into memory. The primary task of 1132 * this function is to relocate the dynamic linker. 1133 */ 1134 static void 1135 init_rtld(caddr_t mapbase) 1136 { 1137 Obj_Entry objtmp; /* Temporary rtld object */ 1138 1139 /* 1140 * Conjure up an Obj_Entry structure for the dynamic linker. 1141 * 1142 * The "path" member can't be initialized yet because string constatns 1143 * cannot yet be acessed. Below we will set it correctly. 1144 */ 1145 objtmp.path = NULL; 1146 objtmp.rtld = true; 1147 objtmp.mapbase = mapbase; 1148 #ifdef PIC 1149 objtmp.relocbase = mapbase; 1150 #endif 1151 if (&_DYNAMIC != 0) { 1152 objtmp.dynamic = rtld_dynamic(&objtmp); 1153 digest_dynamic(&objtmp, 1); 1154 assert(objtmp.needed == NULL); 1155 assert(!objtmp.textrel); 1156 1157 /* 1158 * Temporarily put the dynamic linker entry into the object list, so 1159 * that symbols can be found. 1160 */ 1161 1162 relocate_objects(&objtmp, true, &objtmp); 1163 } 1164 1165 /* Initialize the object list. */ 1166 obj_tail = &obj_list; 1167 1168 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1169 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1170 1171 /* Replace the path with a dynamically allocated copy. */ 1172 obj_rtld.path = xstrdup(PATH_RTLD); 1173 1174 r_debug.r_brk = r_debug_state; 1175 r_debug.r_state = RT_CONSISTENT; 1176 } 1177 1178 /* 1179 * Add the init functions from a needed object list (and its recursive 1180 * needed objects) to "list". This is not used directly; it is a helper 1181 * function for initlist_add_objects(). The write lock must be held 1182 * when this function is called. 1183 */ 1184 static void 1185 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1186 { 1187 /* Recursively process the successor needed objects. */ 1188 if (needed->next != NULL) 1189 initlist_add_neededs(needed->next, list); 1190 1191 /* Process the current needed object. */ 1192 if (needed->obj != NULL) 1193 initlist_add_objects(needed->obj, &needed->obj->next, list); 1194 } 1195 1196 /* 1197 * Scan all of the DAGs rooted in the range of objects from "obj" to 1198 * "tail" and add their init functions to "list". This recurses over 1199 * the DAGs and ensure the proper init ordering such that each object's 1200 * needed libraries are initialized before the object itself. At the 1201 * same time, this function adds the objects to the global finalization 1202 * list "list_fini" in the opposite order. The write lock must be 1203 * held when this function is called. 1204 */ 1205 static void 1206 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1207 { 1208 if (obj->init_done) 1209 return; 1210 obj->init_done = true; 1211 1212 /* Recursively process the successor objects. */ 1213 if (&obj->next != tail) 1214 initlist_add_objects(obj->next, tail, list); 1215 1216 /* Recursively process the needed objects. */ 1217 if (obj->needed != NULL) 1218 initlist_add_neededs(obj->needed, list); 1219 1220 /* Add the object to the init list. */ 1221 if (obj->init != NULL) 1222 objlist_push_tail(list, obj); 1223 1224 /* Add the object to the global fini list in the reverse order. */ 1225 if (obj->fini != NULL) 1226 objlist_push_head(&list_fini, obj); 1227 } 1228 1229 static bool 1230 is_exported(const Elf_Sym *def) 1231 { 1232 func_ptr_type value; 1233 const func_ptr_type *p; 1234 1235 value = (func_ptr_type)(obj_rtld.relocbase + def->st_value); 1236 for (p = exports; *p != NULL; p++) 1237 if (*p == value) 1238 return true; 1239 return false; 1240 } 1241 1242 /* 1243 * Given a shared object, traverse its list of needed objects, and load 1244 * each of them. Returns 0 on success. Generates an error message and 1245 * returns -1 on failure. 1246 */ 1247 static int 1248 load_needed_objects(Obj_Entry *first) 1249 { 1250 Obj_Entry *obj; 1251 1252 for (obj = first; obj != NULL; obj = obj->next) { 1253 Needed_Entry *needed; 1254 1255 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1256 const char *name = obj->strtab + needed->name; 1257 char *path = find_library(name, obj); 1258 1259 needed->obj = NULL; 1260 if (path == NULL && !ld_tracing) 1261 return -1; 1262 1263 if (path) { 1264 needed->obj = load_object(path); 1265 if (needed->obj == NULL && !ld_tracing) 1266 return -1; /* XXX - cleanup */ 1267 } 1268 } 1269 } 1270 1271 return 0; 1272 } 1273 1274 #define RTLD_FUNCTRACE "_rtld_functrace" 1275 1276 static int 1277 load_preload_objects(void) 1278 { 1279 char *p = ld_preload; 1280 static const char delim[] = " \t:;"; 1281 1282 if (p == NULL) 1283 return 0; 1284 1285 p += strspn(p, delim); 1286 while (*p != '\0') { 1287 size_t len = strcspn(p, delim); 1288 char *path; 1289 char savech; 1290 Obj_Entry *obj; 1291 const Elf_Sym *sym; 1292 1293 savech = p[len]; 1294 p[len] = '\0'; 1295 if ((path = find_library(p, NULL)) == NULL) 1296 return -1; 1297 obj = load_object(path); 1298 if (obj == NULL) 1299 return -1; /* XXX - cleanup */ 1300 p[len] = savech; 1301 p += len; 1302 p += strspn(p, delim); 1303 1304 /* Check for the magic tracing function */ 1305 sym = symlook_obj(RTLD_FUNCTRACE, elf_hash(RTLD_FUNCTRACE), obj, true); 1306 if (sym != NULL) { 1307 rtld_functrace = (void *)(obj->relocbase + sym->st_value); 1308 rtld_functrace_obj = obj; 1309 } 1310 } 1311 return 0; 1312 } 1313 1314 /* 1315 * Returns a pointer to the Obj_Entry for the object with the given path. 1316 * Returns NULL if no matching object was found. 1317 */ 1318 static Obj_Entry * 1319 find_object(const char *path) 1320 { 1321 Obj_Entry *obj; 1322 1323 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1324 if (strcmp(obj->path, path) == 0) 1325 return(obj); 1326 } 1327 return(NULL); 1328 } 1329 1330 /* 1331 * Returns a pointer to the Obj_Entry for the object matching device and 1332 * inode of the given path. If no matching object was found, the descriptor 1333 * is returned in fd. 1334 * Returns with obj == NULL && fd == -1 on error. 1335 */ 1336 static Obj_Entry * 1337 find_object2(const char *path, int *fd, struct stat *sb) 1338 { 1339 Obj_Entry *obj; 1340 1341 if ((*fd = open(path, O_RDONLY)) == -1) { 1342 _rtld_error("Cannot open \"%s\"", path); 1343 return(NULL); 1344 } 1345 1346 if (fstat(*fd, sb) == -1) { 1347 _rtld_error("Cannot fstat \"%s\"", path); 1348 close(*fd); 1349 *fd = -1; 1350 return NULL; 1351 } 1352 1353 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1354 if (obj->ino == sb->st_ino && obj->dev == sb->st_dev) { 1355 close(*fd); 1356 break; 1357 } 1358 } 1359 1360 return(obj); 1361 } 1362 1363 /* 1364 * Load a shared object into memory, if it is not already loaded. The 1365 * argument must be a string allocated on the heap. This function assumes 1366 * responsibility for freeing it when necessary. 1367 * 1368 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1369 * on failure. 1370 */ 1371 static Obj_Entry * 1372 load_object(char *path) 1373 { 1374 Obj_Entry *obj; 1375 int fd = -1; 1376 struct stat sb; 1377 1378 obj = find_object(path); 1379 if (obj != NULL) { 1380 obj->refcount++; 1381 free(path); 1382 return(obj); 1383 } 1384 1385 obj = find_object2(path, &fd, &sb); 1386 if (obj != NULL) { 1387 obj->refcount++; 1388 free(path); 1389 return(obj); 1390 } else if (fd == -1) { 1391 free(path); 1392 return(NULL); 1393 } 1394 1395 dbg("loading \"%s\"", path); 1396 obj = map_object(fd, path, &sb); 1397 close(fd); 1398 if (obj == NULL) { 1399 free(path); 1400 return NULL; 1401 } 1402 1403 obj->path = path; 1404 digest_dynamic(obj, 0); 1405 1406 *obj_tail = obj; 1407 obj_tail = &obj->next; 1408 obj_count++; 1409 linkmap_add(obj); /* for GDB & dlinfo() */ 1410 1411 dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1, 1412 obj->path); 1413 if (obj->textrel) 1414 dbg(" WARNING: %s has impure text", obj->path); 1415 1416 obj->refcount++; 1417 return obj; 1418 } 1419 1420 /* 1421 * Check for locking violations and die if one is found. 1422 */ 1423 static void 1424 lock_check(void) 1425 { 1426 int rcount, wcount; 1427 1428 rcount = lockinfo.rcount; 1429 wcount = lockinfo.wcount; 1430 assert(rcount >= 0); 1431 assert(wcount >= 0); 1432 if (wcount > 1 || (wcount != 0 && rcount != 0)) { 1433 _rtld_error("Application locking error: %d readers and %d writers" 1434 " in dynamic linker. See DLLOCKINIT(3) in manual pages.", 1435 rcount, wcount); 1436 die(); 1437 } 1438 } 1439 1440 static Obj_Entry * 1441 obj_from_addr(const void *addr) 1442 { 1443 Obj_Entry *obj; 1444 1445 for (obj = obj_list; obj != NULL; obj = obj->next) { 1446 if (addr < (void *) obj->mapbase) 1447 continue; 1448 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1449 return obj; 1450 } 1451 return NULL; 1452 } 1453 1454 /* 1455 * Call the finalization functions for each of the objects in "list" 1456 * which are unreferenced. All of the objects are expected to have 1457 * non-NULL fini functions. 1458 */ 1459 static void 1460 objlist_call_fini(Objlist *list) 1461 { 1462 Objlist_Entry *elm; 1463 char *saved_msg; 1464 1465 /* 1466 * Preserve the current error message since a fini function might 1467 * call into the dynamic linker and overwrite it. 1468 */ 1469 saved_msg = errmsg_save(); 1470 STAILQ_FOREACH(elm, list, link) { 1471 if (elm->obj->refcount == 0) { 1472 dbg("calling fini function for %s", elm->obj->path); 1473 (*elm->obj->fini)(); 1474 } 1475 } 1476 errmsg_restore(saved_msg); 1477 } 1478 1479 /* 1480 * Call the initialization functions for each of the objects in 1481 * "list". All of the objects are expected to have non-NULL init 1482 * functions. 1483 */ 1484 static void 1485 objlist_call_init(Objlist *list) 1486 { 1487 Objlist_Entry *elm; 1488 char *saved_msg; 1489 1490 /* 1491 * Preserve the current error message since an init function might 1492 * call into the dynamic linker and overwrite it. 1493 */ 1494 saved_msg = errmsg_save(); 1495 STAILQ_FOREACH(elm, list, link) { 1496 dbg("calling init function for %s", elm->obj->path); 1497 (*elm->obj->init)(); 1498 } 1499 errmsg_restore(saved_msg); 1500 } 1501 1502 static void 1503 objlist_clear(Objlist *list) 1504 { 1505 Objlist_Entry *elm; 1506 1507 while (!STAILQ_EMPTY(list)) { 1508 elm = STAILQ_FIRST(list); 1509 STAILQ_REMOVE_HEAD(list, link); 1510 free(elm); 1511 } 1512 } 1513 1514 static Objlist_Entry * 1515 objlist_find(Objlist *list, const Obj_Entry *obj) 1516 { 1517 Objlist_Entry *elm; 1518 1519 STAILQ_FOREACH(elm, list, link) 1520 if (elm->obj == obj) 1521 return elm; 1522 return NULL; 1523 } 1524 1525 static void 1526 objlist_init(Objlist *list) 1527 { 1528 STAILQ_INIT(list); 1529 } 1530 1531 static void 1532 objlist_push_head(Objlist *list, Obj_Entry *obj) 1533 { 1534 Objlist_Entry *elm; 1535 1536 elm = NEW(Objlist_Entry); 1537 elm->obj = obj; 1538 STAILQ_INSERT_HEAD(list, elm, link); 1539 } 1540 1541 static void 1542 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1543 { 1544 Objlist_Entry *elm; 1545 1546 elm = NEW(Objlist_Entry); 1547 elm->obj = obj; 1548 STAILQ_INSERT_TAIL(list, elm, link); 1549 } 1550 1551 static void 1552 objlist_remove(Objlist *list, Obj_Entry *obj) 1553 { 1554 Objlist_Entry *elm; 1555 1556 if ((elm = objlist_find(list, obj)) != NULL) { 1557 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1558 free(elm); 1559 } 1560 } 1561 1562 /* 1563 * Remove all of the unreferenced objects from "list". 1564 */ 1565 static void 1566 objlist_remove_unref(Objlist *list) 1567 { 1568 Objlist newlist; 1569 Objlist_Entry *elm; 1570 1571 STAILQ_INIT(&newlist); 1572 while (!STAILQ_EMPTY(list)) { 1573 elm = STAILQ_FIRST(list); 1574 STAILQ_REMOVE_HEAD(list, link); 1575 if (elm->obj->refcount == 0) 1576 free(elm); 1577 else 1578 STAILQ_INSERT_TAIL(&newlist, elm, link); 1579 } 1580 *list = newlist; 1581 } 1582 1583 /* 1584 * Relocate newly-loaded shared objects. The argument is a pointer to 1585 * the Obj_Entry for the first such object. All objects from the first 1586 * to the end of the list of objects are relocated. Returns 0 on success, 1587 * or -1 on failure. 1588 */ 1589 static int 1590 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1591 { 1592 Obj_Entry *obj; 1593 1594 for (obj = first; obj != NULL; obj = obj->next) { 1595 if (obj != rtldobj) 1596 dbg("relocating \"%s\"", obj->path); 1597 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1598 obj->symtab == NULL || obj->strtab == NULL) { 1599 _rtld_error("%s: Shared object has no run-time symbol table", 1600 obj->path); 1601 return -1; 1602 } 1603 1604 if (obj->textrel) { 1605 /* There are relocations to the write-protected text segment. */ 1606 if (mprotect(obj->mapbase, obj->textsize, 1607 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1608 _rtld_error("%s: Cannot write-enable text segment: %s", 1609 obj->path, strerror(errno)); 1610 return -1; 1611 } 1612 } 1613 1614 /* Process the non-PLT relocations. */ 1615 if (reloc_non_plt(obj, rtldobj)) 1616 return -1; 1617 1618 /* 1619 * Reprotect the text segment. Make sure it is included in the 1620 * core dump since we modified it. This unfortunately causes the 1621 * entire text segment to core-out but we don't have much of a 1622 * choice. We could try to only reenable core dumps on pages 1623 * in which relocations occured but that is likely most of the text 1624 * pages anyway, and even that would not work because the rest of 1625 * the text pages would wind up as a read-only OBJT_DEFAULT object 1626 * (created due to our modifications) backed by the original OBJT_VNODE 1627 * object, and the ELF coredump code is currently only able to dump 1628 * vnode records for pure vnode-backed mappings, not vnode backings 1629 * to memory objects. 1630 */ 1631 if (obj->textrel) { 1632 madvise(obj->mapbase, obj->textsize, MADV_CORE); 1633 if (mprotect(obj->mapbase, obj->textsize, 1634 PROT_READ|PROT_EXEC) == -1) { 1635 _rtld_error("%s: Cannot write-protect text segment: %s", 1636 obj->path, strerror(errno)); 1637 return -1; 1638 } 1639 } 1640 1641 /* Process the PLT relocations. */ 1642 if (reloc_plt(obj) == -1) 1643 return -1; 1644 /* Relocate the jump slots if we are doing immediate binding. */ 1645 if (obj->bind_now || bind_now) 1646 if (reloc_jmpslots(obj) == -1) 1647 return -1; 1648 1649 1650 /* 1651 * Set up the magic number and version in the Obj_Entry. These 1652 * were checked in the crt1.o from the original ElfKit, so we 1653 * set them for backward compatibility. 1654 */ 1655 obj->magic = RTLD_MAGIC; 1656 obj->version = RTLD_VERSION; 1657 1658 /* Set the special PLT or GOT entries. */ 1659 init_pltgot(obj); 1660 } 1661 1662 return 0; 1663 } 1664 1665 /* 1666 * Cleanup procedure. It will be called (by the atexit mechanism) just 1667 * before the process exits. 1668 */ 1669 static void 1670 rtld_exit(void) 1671 { 1672 Obj_Entry *obj; 1673 1674 dbg("rtld_exit()"); 1675 /* Clear all the reference counts so the fini functions will be called. */ 1676 for (obj = obj_list; obj != NULL; obj = obj->next) 1677 obj->refcount = 0; 1678 objlist_call_fini(&list_fini); 1679 /* No need to remove the items from the list, since we are exiting. */ 1680 } 1681 1682 static void * 1683 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1684 { 1685 if (path == NULL) 1686 return (NULL); 1687 1688 path += strspn(path, ":;"); 1689 while (*path != '\0') { 1690 size_t len; 1691 char *res; 1692 1693 len = strcspn(path, ":;"); 1694 res = callback(path, len, arg); 1695 1696 if (res != NULL) 1697 return (res); 1698 1699 path += len; 1700 path += strspn(path, ":;"); 1701 } 1702 1703 return (NULL); 1704 } 1705 1706 struct try_library_args { 1707 const char *name; 1708 size_t namelen; 1709 char *buffer; 1710 size_t buflen; 1711 }; 1712 1713 static void * 1714 try_library_path(const char *dir, size_t dirlen, void *param) 1715 { 1716 struct try_library_args *arg; 1717 1718 arg = param; 1719 if (*dir == '/' || trust) { 1720 char *pathname; 1721 1722 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1723 return (NULL); 1724 1725 pathname = arg->buffer; 1726 strncpy(pathname, dir, dirlen); 1727 pathname[dirlen] = '/'; 1728 strcpy(pathname + dirlen + 1, arg->name); 1729 1730 dbg(" Trying \"%s\"", pathname); 1731 if (access(pathname, F_OK) == 0) { /* We found it */ 1732 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1733 strcpy(pathname, arg->buffer); 1734 return (pathname); 1735 } 1736 } 1737 return (NULL); 1738 } 1739 1740 static char * 1741 search_library_path(const char *name, const char *path) 1742 { 1743 char *p; 1744 struct try_library_args arg; 1745 1746 if (path == NULL) 1747 return NULL; 1748 1749 arg.name = name; 1750 arg.namelen = strlen(name); 1751 arg.buffer = xmalloc(PATH_MAX); 1752 arg.buflen = PATH_MAX; 1753 1754 p = path_enumerate(path, try_library_path, &arg); 1755 1756 free(arg.buffer); 1757 1758 return (p); 1759 } 1760 1761 int 1762 dlclose(void *handle) 1763 { 1764 Obj_Entry *root; 1765 1766 wlock_acquire(); 1767 root = dlcheck(handle); 1768 if (root == NULL) { 1769 wlock_release(); 1770 return -1; 1771 } 1772 1773 /* Unreference the object and its dependencies. */ 1774 root->dl_refcount--; 1775 unref_dag(root); 1776 1777 if (root->refcount == 0) { 1778 /* 1779 * The object is no longer referenced, so we must unload it. 1780 * First, call the fini functions with no locks held. 1781 */ 1782 wlock_release(); 1783 objlist_call_fini(&list_fini); 1784 wlock_acquire(); 1785 objlist_remove_unref(&list_fini); 1786 1787 /* Finish cleaning up the newly-unreferenced objects. */ 1788 GDB_STATE(RT_DELETE,&root->linkmap); 1789 unload_object(root); 1790 GDB_STATE(RT_CONSISTENT,NULL); 1791 } 1792 wlock_release(); 1793 return 0; 1794 } 1795 1796 const char * 1797 dlerror(void) 1798 { 1799 char *msg = error_message; 1800 error_message = NULL; 1801 return msg; 1802 } 1803 1804 void * 1805 dlopen(const char *name, int mode) 1806 { 1807 Obj_Entry **old_obj_tail; 1808 Obj_Entry *obj; 1809 Objlist initlist; 1810 int result; 1811 1812 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1813 if (ld_tracing != NULL) 1814 environ = (char **)*get_program_var_addr("environ"); 1815 1816 objlist_init(&initlist); 1817 1818 wlock_acquire(); 1819 GDB_STATE(RT_ADD,NULL); 1820 1821 old_obj_tail = obj_tail; 1822 obj = NULL; 1823 if (name == NULL) { 1824 obj = obj_main; 1825 obj->refcount++; 1826 } else { 1827 char *path = find_library(name, obj_main); 1828 if (path != NULL) 1829 obj = load_object(path); 1830 } 1831 1832 if (obj) { 1833 obj->dl_refcount++; 1834 if ((mode & RTLD_GLOBAL) && objlist_find(&list_global, obj) == NULL) 1835 objlist_push_tail(&list_global, obj); 1836 mode &= RTLD_MODEMASK; 1837 if (*old_obj_tail != NULL) { /* We loaded something new. */ 1838 assert(*old_obj_tail == obj); 1839 1840 result = load_needed_objects(obj); 1841 if (result != -1 && ld_tracing) 1842 goto trace; 1843 1844 if (result == -1 || 1845 (init_dag(obj), relocate_objects(obj, mode == RTLD_NOW, 1846 &obj_rtld)) == -1) { 1847 obj->dl_refcount--; 1848 unref_dag(obj); 1849 if (obj->refcount == 0) 1850 unload_object(obj); 1851 obj = NULL; 1852 } else { 1853 /* Make list of init functions to call. */ 1854 initlist_add_objects(obj, &obj->next, &initlist); 1855 } 1856 } else if (ld_tracing) 1857 goto trace; 1858 } 1859 1860 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 1861 1862 /* Call the init functions with no locks held. */ 1863 wlock_release(); 1864 objlist_call_init(&initlist); 1865 wlock_acquire(); 1866 objlist_clear(&initlist); 1867 wlock_release(); 1868 return obj; 1869 trace: 1870 trace_loaded_objects(obj); 1871 wlock_release(); 1872 exit(0); 1873 } 1874 1875 void * 1876 dlsym(void *handle, const char *name) 1877 { 1878 const Obj_Entry *obj; 1879 unsigned long hash; 1880 const Elf_Sym *def; 1881 const Obj_Entry *defobj; 1882 1883 hash = elf_hash(name); 1884 def = NULL; 1885 defobj = NULL; 1886 1887 rlock_acquire(); 1888 if (handle == NULL || handle == RTLD_NEXT || 1889 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 1890 void *retaddr; 1891 1892 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 1893 if ((obj = obj_from_addr(retaddr)) == NULL) { 1894 _rtld_error("Cannot determine caller's shared object"); 1895 rlock_release(); 1896 return NULL; 1897 } 1898 if (handle == NULL) { /* Just the caller's shared object. */ 1899 def = symlook_obj(name, hash, obj, true); 1900 defobj = obj; 1901 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 1902 handle == RTLD_SELF) { /* ... caller included */ 1903 if (handle == RTLD_NEXT) 1904 obj = obj->next; 1905 for (; obj != NULL; obj = obj->next) { 1906 if ((def = symlook_obj(name, hash, obj, true)) != NULL) { 1907 defobj = obj; 1908 break; 1909 } 1910 } 1911 } else { 1912 assert(handle == RTLD_DEFAULT); 1913 def = symlook_default(name, hash, obj, &defobj, true); 1914 } 1915 } else { 1916 DoneList donelist; 1917 1918 if ((obj = dlcheck(handle)) == NULL) { 1919 rlock_release(); 1920 return NULL; 1921 } 1922 1923 donelist_init(&donelist); 1924 if (obj->mainprog) { 1925 /* Search main program and all libraries loaded by it. */ 1926 def = symlook_list(name, hash, &list_main, &defobj, true, 1927 &donelist); 1928 } else { 1929 Needed_Entry fake; 1930 1931 /* Search the given object and its needed objects. */ 1932 fake.next = NULL; 1933 fake.obj = (Obj_Entry *)obj; 1934 fake.name = 0; 1935 def = symlook_needed(name, hash, &fake, &defobj, true, 1936 &donelist); 1937 } 1938 } 1939 1940 if (def != NULL) { 1941 rlock_release(); 1942 return defobj->relocbase + def->st_value; 1943 } 1944 1945 _rtld_error("Undefined symbol \"%s\"", name); 1946 rlock_release(); 1947 return NULL; 1948 } 1949 1950 int 1951 dladdr(const void *addr, Dl_info *info) 1952 { 1953 const Obj_Entry *obj; 1954 const Elf_Sym *def; 1955 void *symbol_addr; 1956 unsigned long symoffset; 1957 1958 rlock_acquire(); 1959 obj = obj_from_addr(addr); 1960 if (obj == NULL) { 1961 _rtld_error("No shared object contains address"); 1962 rlock_release(); 1963 return 0; 1964 } 1965 info->dli_fname = obj->path; 1966 info->dli_fbase = obj->mapbase; 1967 info->dli_saddr = (void *)0; 1968 info->dli_sname = NULL; 1969 1970 /* 1971 * Walk the symbol list looking for the symbol whose address is 1972 * closest to the address sent in. 1973 */ 1974 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 1975 def = obj->symtab + symoffset; 1976 1977 /* 1978 * For skip the symbol if st_shndx is either SHN_UNDEF or 1979 * SHN_COMMON. 1980 */ 1981 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 1982 continue; 1983 1984 /* 1985 * If the symbol is greater than the specified address, or if it 1986 * is further away from addr than the current nearest symbol, 1987 * then reject it. 1988 */ 1989 symbol_addr = obj->relocbase + def->st_value; 1990 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 1991 continue; 1992 1993 /* Update our idea of the nearest symbol. */ 1994 info->dli_sname = obj->strtab + def->st_name; 1995 info->dli_saddr = symbol_addr; 1996 1997 /* Exact match? */ 1998 if (info->dli_saddr == addr) 1999 break; 2000 } 2001 rlock_release(); 2002 return 1; 2003 } 2004 2005 int 2006 dlinfo(void *handle, int request, void *p) 2007 { 2008 const Obj_Entry *obj; 2009 int error; 2010 2011 rlock_acquire(); 2012 2013 if (handle == NULL || handle == RTLD_SELF) { 2014 void *retaddr; 2015 2016 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2017 if ((obj = obj_from_addr(retaddr)) == NULL) 2018 _rtld_error("Cannot determine caller's shared object"); 2019 } else 2020 obj = dlcheck(handle); 2021 2022 if (obj == NULL) { 2023 rlock_release(); 2024 return (-1); 2025 } 2026 2027 error = 0; 2028 switch (request) { 2029 case RTLD_DI_LINKMAP: 2030 *((struct link_map const **)p) = &obj->linkmap; 2031 break; 2032 case RTLD_DI_ORIGIN: 2033 error = rtld_dirname(obj->path, p); 2034 break; 2035 2036 case RTLD_DI_SERINFOSIZE: 2037 case RTLD_DI_SERINFO: 2038 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2039 break; 2040 2041 default: 2042 _rtld_error("Invalid request %d passed to dlinfo()", request); 2043 error = -1; 2044 } 2045 2046 rlock_release(); 2047 2048 return (error); 2049 } 2050 2051 struct fill_search_info_args { 2052 int request; 2053 unsigned int flags; 2054 Dl_serinfo *serinfo; 2055 Dl_serpath *serpath; 2056 char *strspace; 2057 }; 2058 2059 static void * 2060 fill_search_info(const char *dir, size_t dirlen, void *param) 2061 { 2062 struct fill_search_info_args *arg; 2063 2064 arg = param; 2065 2066 if (arg->request == RTLD_DI_SERINFOSIZE) { 2067 arg->serinfo->dls_cnt ++; 2068 arg->serinfo->dls_size += dirlen + 1; 2069 } else { 2070 struct dl_serpath *s_entry; 2071 2072 s_entry = arg->serpath; 2073 s_entry->dls_name = arg->strspace; 2074 s_entry->dls_flags = arg->flags; 2075 2076 strncpy(arg->strspace, dir, dirlen); 2077 arg->strspace[dirlen] = '\0'; 2078 2079 arg->strspace += dirlen + 1; 2080 arg->serpath++; 2081 } 2082 2083 return (NULL); 2084 } 2085 2086 static int 2087 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2088 { 2089 struct dl_serinfo _info; 2090 struct fill_search_info_args args; 2091 2092 args.request = RTLD_DI_SERINFOSIZE; 2093 args.serinfo = &_info; 2094 2095 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2096 _info.dls_cnt = 0; 2097 2098 path_enumerate(ld_library_path, fill_search_info, &args); 2099 path_enumerate(obj->rpath, fill_search_info, &args); 2100 path_enumerate(gethints(), fill_search_info, &args); 2101 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2102 2103 2104 if (request == RTLD_DI_SERINFOSIZE) { 2105 info->dls_size = _info.dls_size; 2106 info->dls_cnt = _info.dls_cnt; 2107 return (0); 2108 } 2109 2110 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2111 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2112 return (-1); 2113 } 2114 2115 args.request = RTLD_DI_SERINFO; 2116 args.serinfo = info; 2117 args.serpath = &info->dls_serpath[0]; 2118 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2119 2120 args.flags = LA_SER_LIBPATH; 2121 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2122 return (-1); 2123 2124 args.flags = LA_SER_RUNPATH; 2125 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2126 return (-1); 2127 2128 args.flags = LA_SER_CONFIG; 2129 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2130 return (-1); 2131 2132 args.flags = LA_SER_DEFAULT; 2133 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2134 return (-1); 2135 return (0); 2136 } 2137 2138 static int 2139 rtld_dirname(const char *path, char *bname) 2140 { 2141 const char *endp; 2142 2143 /* Empty or NULL string gets treated as "." */ 2144 if (path == NULL || *path == '\0') { 2145 bname[0] = '.'; 2146 bname[1] = '\0'; 2147 return (0); 2148 } 2149 2150 /* Strip trailing slashes */ 2151 endp = path + strlen(path) - 1; 2152 while (endp > path && *endp == '/') 2153 endp--; 2154 2155 /* Find the start of the dir */ 2156 while (endp > path && *endp != '/') 2157 endp--; 2158 2159 /* Either the dir is "/" or there are no slashes */ 2160 if (endp == path) { 2161 bname[0] = *endp == '/' ? '/' : '.'; 2162 bname[1] = '\0'; 2163 return (0); 2164 } else { 2165 do { 2166 endp--; 2167 } while (endp > path && *endp == '/'); 2168 } 2169 2170 if (endp - path + 2 > PATH_MAX) 2171 { 2172 _rtld_error("Filename is too long: %s", path); 2173 return(-1); 2174 } 2175 2176 strncpy(bname, path, endp - path + 1); 2177 bname[endp - path + 1] = '\0'; 2178 return (0); 2179 } 2180 2181 static void 2182 linkmap_add(Obj_Entry *obj) 2183 { 2184 struct link_map *l = &obj->linkmap; 2185 struct link_map *prev; 2186 2187 obj->linkmap.l_name = obj->path; 2188 obj->linkmap.l_addr = obj->mapbase; 2189 obj->linkmap.l_ld = obj->dynamic; 2190 #ifdef __mips__ 2191 /* GDB needs load offset on MIPS to use the symbols */ 2192 obj->linkmap.l_offs = obj->relocbase; 2193 #endif 2194 2195 if (r_debug.r_map == NULL) { 2196 r_debug.r_map = l; 2197 return; 2198 } 2199 2200 /* 2201 * Scan to the end of the list, but not past the entry for the 2202 * dynamic linker, which we want to keep at the very end. 2203 */ 2204 for (prev = r_debug.r_map; 2205 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2206 prev = prev->l_next) 2207 ; 2208 2209 /* Link in the new entry. */ 2210 l->l_prev = prev; 2211 l->l_next = prev->l_next; 2212 if (l->l_next != NULL) 2213 l->l_next->l_prev = l; 2214 prev->l_next = l; 2215 } 2216 2217 static void 2218 linkmap_delete(Obj_Entry *obj) 2219 { 2220 struct link_map *l = &obj->linkmap; 2221 2222 if (l->l_prev == NULL) { 2223 if ((r_debug.r_map = l->l_next) != NULL) 2224 l->l_next->l_prev = NULL; 2225 return; 2226 } 2227 2228 if ((l->l_prev->l_next = l->l_next) != NULL) 2229 l->l_next->l_prev = l->l_prev; 2230 } 2231 2232 /* 2233 * Function for the debugger to set a breakpoint on to gain control. 2234 * 2235 * The two parameters allow the debugger to easily find and determine 2236 * what the runtime loader is doing and to whom it is doing it. 2237 * 2238 * When the loadhook trap is hit (r_debug_state, set at program 2239 * initialization), the arguments can be found on the stack: 2240 * 2241 * +8 struct link_map *m 2242 * +4 struct r_debug *rd 2243 * +0 RetAddr 2244 */ 2245 void 2246 r_debug_state(struct r_debug* rd, struct link_map *m) 2247 { 2248 } 2249 2250 /* 2251 * Get address of the pointer variable in the main program. 2252 */ 2253 static const void ** 2254 get_program_var_addr(const char *name) 2255 { 2256 const Obj_Entry *obj; 2257 unsigned long hash; 2258 2259 hash = elf_hash(name); 2260 for (obj = obj_main; obj != NULL; obj = obj->next) { 2261 const Elf_Sym *def; 2262 2263 if ((def = symlook_obj(name, hash, obj, false)) != NULL) { 2264 const void **addr; 2265 2266 addr = (const void **)(obj->relocbase + def->st_value); 2267 return addr; 2268 } 2269 } 2270 return NULL; 2271 } 2272 2273 /* 2274 * Set a pointer variable in the main program to the given value. This 2275 * is used to set key variables such as "environ" before any of the 2276 * init functions are called. 2277 */ 2278 static void 2279 set_program_var(const char *name, const void *value) 2280 { 2281 const void **addr; 2282 2283 if ((addr = get_program_var_addr(name)) != NULL) { 2284 dbg("\"%s\": *%p <-- %p", name, addr, value); 2285 *addr = value; 2286 } 2287 } 2288 2289 /* 2290 * This is a special version of getenv which is far more efficient 2291 * at finding LD_ environment vars. 2292 */ 2293 static 2294 const char * 2295 _getenv_ld(const char *id) 2296 { 2297 const char *envp; 2298 int i, j; 2299 int idlen = strlen(id); 2300 2301 if (ld_index == LD_ARY_CACHE) 2302 return(getenv(id)); 2303 if (ld_index == 0) { 2304 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 2305 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 2306 ld_ary[j++] = envp; 2307 } 2308 if (j == 0) 2309 ld_ary[j++] = ""; 2310 ld_index = j; 2311 } 2312 for (i = ld_index - 1; i >= 0; --i) { 2313 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 2314 return(ld_ary[i] + idlen + 1); 2315 } 2316 return(NULL); 2317 } 2318 2319 /* 2320 * Given a symbol name in a referencing object, find the corresponding 2321 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2322 * no definition was found. Returns a pointer to the Obj_Entry of the 2323 * defining object via the reference parameter DEFOBJ_OUT. 2324 */ 2325 static const Elf_Sym * 2326 symlook_default(const char *name, unsigned long hash, 2327 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt) 2328 { 2329 DoneList donelist; 2330 const Elf_Sym *def; 2331 const Elf_Sym *symp; 2332 const Obj_Entry *obj; 2333 const Obj_Entry *defobj; 2334 const Objlist_Entry *elm; 2335 def = NULL; 2336 defobj = NULL; 2337 donelist_init(&donelist); 2338 2339 /* Look first in the referencing object if linked symbolically. */ 2340 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2341 symp = symlook_obj(name, hash, refobj, in_plt); 2342 if (symp != NULL) { 2343 def = symp; 2344 defobj = refobj; 2345 } 2346 } 2347 2348 /* Search all objects loaded at program start up. */ 2349 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2350 symp = symlook_list(name, hash, &list_main, &obj, in_plt, &donelist); 2351 if (symp != NULL && 2352 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2353 def = symp; 2354 defobj = obj; 2355 } 2356 } 2357 2358 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2359 STAILQ_FOREACH(elm, &list_global, link) { 2360 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2361 break; 2362 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt, 2363 &donelist); 2364 if (symp != NULL && 2365 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2366 def = symp; 2367 defobj = obj; 2368 } 2369 } 2370 2371 /* Search all dlopened DAGs containing the referencing object. */ 2372 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2373 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2374 break; 2375 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt, 2376 &donelist); 2377 if (symp != NULL && 2378 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2379 def = symp; 2380 defobj = obj; 2381 } 2382 } 2383 2384 /* 2385 * Search the dynamic linker itself, and possibly resolve the 2386 * symbol from there. This is how the application links to 2387 * dynamic linker services such as dlopen. Only the values listed 2388 * in the "exports" array can be resolved from the dynamic linker. 2389 */ 2390 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2391 symp = symlook_obj(name, hash, &obj_rtld, in_plt); 2392 if (symp != NULL && is_exported(symp)) { 2393 def = symp; 2394 defobj = &obj_rtld; 2395 } 2396 } 2397 2398 if (def != NULL) 2399 *defobj_out = defobj; 2400 return def; 2401 } 2402 2403 static const Elf_Sym * 2404 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2405 const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp) 2406 { 2407 const Elf_Sym *symp; 2408 const Elf_Sym *def; 2409 const Obj_Entry *defobj; 2410 const Objlist_Entry *elm; 2411 2412 def = NULL; 2413 defobj = NULL; 2414 STAILQ_FOREACH(elm, objlist, link) { 2415 if (donelist_check(dlp, elm->obj)) 2416 continue; 2417 if ((symp = symlook_obj(name, hash, elm->obj, in_plt)) != NULL) { 2418 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2419 def = symp; 2420 defobj = elm->obj; 2421 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2422 break; 2423 } 2424 } 2425 } 2426 if (def != NULL) 2427 *defobj_out = defobj; 2428 return def; 2429 } 2430 2431 /* 2432 * Search the symbol table of a shared object and all objects needed 2433 * by it for a symbol of the given name. Search order is 2434 * breadth-first. Returns a pointer to the symbol, or NULL if no 2435 * definition was found. 2436 */ 2437 static const Elf_Sym * 2438 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2439 const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp) 2440 { 2441 const Elf_Sym *def, *def_w; 2442 const Needed_Entry *n; 2443 const Obj_Entry *obj, *defobj, *defobj1; 2444 2445 def = def_w = NULL; 2446 defobj = NULL; 2447 for (n = needed; n != NULL; n = n->next) { 2448 if ((obj = n->obj) == NULL || 2449 donelist_check(dlp, obj) || 2450 (def = symlook_obj(name, hash, obj, in_plt)) == NULL) 2451 continue; 2452 defobj = obj; 2453 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2454 *defobj_out = defobj; 2455 return (def); 2456 } 2457 } 2458 /* 2459 * There we come when either symbol definition is not found in 2460 * directly needed objects, or found symbol is weak. 2461 */ 2462 for (n = needed; n != NULL; n = n->next) { 2463 if ((obj = n->obj) == NULL) 2464 continue; 2465 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2466 in_plt, dlp); 2467 if (def_w == NULL) 2468 continue; 2469 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2470 def = def_w; 2471 defobj = defobj1; 2472 } 2473 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2474 break; 2475 } 2476 if (def != NULL) 2477 *defobj_out = defobj; 2478 return def; 2479 } 2480 2481 /* 2482 * Search the symbol table of a single shared object for a symbol of 2483 * the given name. Returns a pointer to the symbol, or NULL if no 2484 * definition was found. 2485 * 2486 * The symbol's hash value is passed in for efficiency reasons; that 2487 * eliminates many recomputations of the hash value. 2488 */ 2489 const Elf_Sym * 2490 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2491 bool in_plt) 2492 { 2493 if (obj->buckets != NULL) { 2494 unsigned long symnum = obj->buckets[hash % obj->nbuckets]; 2495 2496 while (symnum != STN_UNDEF) { 2497 const Elf_Sym *symp; 2498 const char *strp; 2499 2500 if (symnum >= obj->nchains) 2501 return NULL; /* Bad object */ 2502 symp = obj->symtab + symnum; 2503 strp = obj->strtab + symp->st_name; 2504 2505 if (name[0] == strp[0] && strcmp(name, strp) == 0) 2506 return symp->st_shndx != SHN_UNDEF || 2507 (!in_plt && symp->st_value != 0 && 2508 ELF_ST_TYPE(symp->st_info) == STT_FUNC) ? symp : NULL; 2509 2510 symnum = obj->chains[symnum]; 2511 } 2512 } 2513 return NULL; 2514 } 2515 2516 static void 2517 trace_loaded_objects(Obj_Entry *obj) 2518 { 2519 const char *fmt1, *fmt2, *fmt, *main_local; 2520 int c; 2521 2522 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2523 main_local = ""; 2524 2525 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2526 fmt1 = "\t%o => %p (%x)\n"; 2527 2528 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2529 fmt2 = "\t%o (%x)\n"; 2530 2531 for (; obj; obj = obj->next) { 2532 Needed_Entry *needed; 2533 char *name, *path; 2534 bool is_lib; 2535 2536 for (needed = obj->needed; needed; needed = needed->next) { 2537 if (needed->obj != NULL) { 2538 if (needed->obj->traced) 2539 continue; 2540 needed->obj->traced = true; 2541 path = needed->obj->path; 2542 } else 2543 path = "not found"; 2544 2545 name = (char *)obj->strtab + needed->name; 2546 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2547 2548 fmt = is_lib ? fmt1 : fmt2; 2549 while ((c = *fmt++) != '\0') { 2550 switch (c) { 2551 default: 2552 putchar(c); 2553 continue; 2554 case '\\': 2555 switch (c = *fmt) { 2556 case '\0': 2557 continue; 2558 case 'n': 2559 putchar('\n'); 2560 break; 2561 case 't': 2562 putchar('\t'); 2563 break; 2564 } 2565 break; 2566 case '%': 2567 switch (c = *fmt) { 2568 case '\0': 2569 continue; 2570 case '%': 2571 default: 2572 putchar(c); 2573 break; 2574 case 'A': 2575 printf("%s", main_local); 2576 break; 2577 case 'a': 2578 printf("%s", obj_main->path); 2579 break; 2580 case 'o': 2581 printf("%s", name); 2582 break; 2583 #if 0 2584 case 'm': 2585 printf("%d", sodp->sod_major); 2586 break; 2587 case 'n': 2588 printf("%d", sodp->sod_minor); 2589 break; 2590 #endif 2591 case 'p': 2592 printf("%s", path); 2593 break; 2594 case 'x': 2595 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2596 break; 2597 } 2598 break; 2599 } 2600 ++fmt; 2601 } 2602 } 2603 } 2604 } 2605 2606 /* 2607 * Unload a dlopened object and its dependencies from memory and from 2608 * our data structures. It is assumed that the DAG rooted in the 2609 * object has already been unreferenced, and that the object has a 2610 * reference count of 0. 2611 */ 2612 static void 2613 unload_object(Obj_Entry *root) 2614 { 2615 Obj_Entry *obj; 2616 Obj_Entry **linkp; 2617 2618 assert(root->refcount == 0); 2619 2620 /* 2621 * Pass over the DAG removing unreferenced objects from 2622 * appropriate lists. 2623 */ 2624 unlink_object(root); 2625 2626 /* Unmap all objects that are no longer referenced. */ 2627 linkp = &obj_list->next; 2628 while ((obj = *linkp) != NULL) { 2629 if (obj->refcount == 0) { 2630 dbg("unloading \"%s\"", obj->path); 2631 munmap(obj->mapbase, obj->mapsize); 2632 linkmap_delete(obj); 2633 *linkp = obj->next; 2634 obj_count--; 2635 obj_free(obj); 2636 } else 2637 linkp = &obj->next; 2638 } 2639 obj_tail = linkp; 2640 } 2641 2642 static void 2643 unlink_object(Obj_Entry *root) 2644 { 2645 const Needed_Entry *needed; 2646 Objlist_Entry *elm; 2647 2648 if (root->refcount == 0) { 2649 /* Remove the object from the RTLD_GLOBAL list. */ 2650 objlist_remove(&list_global, root); 2651 2652 /* Remove the object from all objects' DAG lists. */ 2653 STAILQ_FOREACH(elm, &root->dagmembers , link) 2654 objlist_remove(&elm->obj->dldags, root); 2655 } 2656 2657 for (needed = root->needed; needed != NULL; needed = needed->next) 2658 if (needed->obj != NULL) 2659 unlink_object(needed->obj); 2660 } 2661 2662 static void 2663 unref_dag(Obj_Entry *root) 2664 { 2665 const Needed_Entry *needed; 2666 2667 if (root->refcount == 0) 2668 return; 2669 root->refcount--; 2670 if (root->refcount == 0) 2671 for (needed = root->needed; needed != NULL; needed = needed->next) 2672 if (needed->obj != NULL) 2673 unref_dag(needed->obj); 2674 } 2675 2676 /* 2677 * Common code for MD __tls_get_addr(). 2678 */ 2679 void * 2680 tls_get_addr_common(void **dtvp, int index, size_t offset) 2681 { 2682 Elf_Addr* dtv = *dtvp; 2683 2684 /* Check dtv generation in case new modules have arrived */ 2685 if (dtv[0] != tls_dtv_generation) { 2686 Elf_Addr* newdtv; 2687 int to_copy; 2688 2689 wlock_acquire(); 2690 2691 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 2692 to_copy = dtv[1]; 2693 if (to_copy > tls_max_index) 2694 to_copy = tls_max_index; 2695 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 2696 newdtv[0] = tls_dtv_generation; 2697 newdtv[1] = tls_max_index; 2698 free(dtv); 2699 *dtvp = newdtv; 2700 2701 wlock_release(); 2702 } 2703 2704 /* Dynamically allocate module TLS if necessary */ 2705 if (!dtv[index + 1]) { 2706 /* XXX 2707 * here we should avoid to be re-entered by signal handler 2708 * code, I assume wlock_acquire will masked all signals, 2709 * otherwise there is race and dead lock thread itself. 2710 */ 2711 wlock_acquire(); 2712 if (!dtv[index + 1]) 2713 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 2714 wlock_release(); 2715 } 2716 2717 return (void*) (dtv[index + 1] + offset); 2718 } 2719 2720 #if defined(RTLD_STATIC_TLS_VARIANT_II) 2721 2722 /* 2723 * Allocate the static TLS area. Return a pointer to the TCB. The 2724 * static area is based on negative offsets relative to the tcb. 2725 * 2726 * The TCB contains an errno pointer for the system call layer, but because 2727 * we are the RTLD we really have no idea how the caller was compiled so 2728 * the information has to be passed in. errno can either be: 2729 * 2730 * type 0 errno is a simple non-TLS global pointer. 2731 * (special case for e.g. libc_rtld) 2732 * type 1 errno accessed by GOT entry (dynamically linked programs) 2733 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 2734 */ 2735 struct tls_tcb * 2736 allocate_tls(Obj_Entry *objs) 2737 { 2738 Obj_Entry *obj; 2739 size_t data_size; 2740 size_t dtv_size; 2741 struct tls_tcb *tcb; 2742 Elf_Addr *dtv; 2743 Elf_Addr addr; 2744 2745 /* 2746 * Allocate the new TCB. static TLS storage is placed just before the 2747 * TCB to support the %gs:OFFSET (negative offset) model. 2748 */ 2749 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 2750 ~RTLD_STATIC_TLS_ALIGN_MASK; 2751 tcb = malloc(data_size + sizeof(*tcb)); 2752 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 2753 2754 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 2755 dtv = malloc(dtv_size); 2756 bzero(dtv, dtv_size); 2757 2758 #ifdef RTLD_TCB_HAS_SELF_POINTER 2759 tcb->tcb_self = tcb; 2760 #endif 2761 tcb->tcb_dtv = dtv; 2762 tcb->tcb_pthread = NULL; 2763 2764 dtv[0] = tls_dtv_generation; 2765 dtv[1] = tls_max_index; 2766 2767 for (obj = objs; obj; obj = obj->next) { 2768 if (obj->tlsoffset) { 2769 addr = (Elf_Addr)tcb - obj->tlsoffset; 2770 memset((void *)(addr + obj->tlsinitsize), 2771 0, obj->tlssize - obj->tlsinitsize); 2772 if (obj->tlsinit) 2773 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 2774 dtv[obj->tlsindex + 1] = addr; 2775 } 2776 } 2777 return(tcb); 2778 } 2779 2780 void 2781 free_tls(struct tls_tcb *tcb) 2782 { 2783 Elf_Addr *dtv; 2784 int dtv_size, i; 2785 Elf_Addr tls_start, tls_end; 2786 size_t data_size; 2787 2788 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 2789 ~RTLD_STATIC_TLS_ALIGN_MASK; 2790 dtv = tcb->tcb_dtv; 2791 dtv_size = dtv[1]; 2792 tls_end = (Elf_Addr)tcb; 2793 tls_start = (Elf_Addr)tcb - data_size; 2794 for (i = 0; i < dtv_size; i++) { 2795 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 2796 free((void *)dtv[i+2]); 2797 } 2798 } 2799 free((void *)tls_start); 2800 } 2801 2802 #else 2803 #error "Unsupported TLS layout" 2804 #endif 2805 2806 /* 2807 * Allocate TLS block for module with given index. 2808 */ 2809 void * 2810 allocate_module_tls(int index) 2811 { 2812 Obj_Entry* obj; 2813 char* p; 2814 2815 for (obj = obj_list; obj; obj = obj->next) { 2816 if (obj->tlsindex == index) 2817 break; 2818 } 2819 if (!obj) { 2820 _rtld_error("Can't find module with TLS index %d", index); 2821 die(); 2822 } 2823 2824 p = malloc(obj->tlssize); 2825 memcpy(p, obj->tlsinit, obj->tlsinitsize); 2826 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 2827 2828 return p; 2829 } 2830 2831 bool 2832 allocate_tls_offset(Obj_Entry *obj) 2833 { 2834 size_t off; 2835 2836 if (obj->tls_done) 2837 return true; 2838 2839 if (obj->tlssize == 0) { 2840 obj->tls_done = true; 2841 return true; 2842 } 2843 2844 if (obj->tlsindex == 1) 2845 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 2846 else 2847 off = calculate_tls_offset(tls_last_offset, tls_last_size, 2848 obj->tlssize, obj->tlsalign); 2849 2850 /* 2851 * If we have already fixed the size of the static TLS block, we 2852 * must stay within that size. When allocating the static TLS, we 2853 * leave a small amount of space spare to be used for dynamically 2854 * loading modules which use static TLS. 2855 */ 2856 if (tls_static_space) { 2857 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 2858 return false; 2859 } 2860 2861 tls_last_offset = obj->tlsoffset = off; 2862 tls_last_size = obj->tlssize; 2863 obj->tls_done = true; 2864 2865 return true; 2866 } 2867 2868 void 2869 free_tls_offset(Obj_Entry *obj) 2870 { 2871 #ifdef RTLD_STATIC_TLS_VARIANT_II 2872 /* 2873 * If we were the last thing to allocate out of the static TLS 2874 * block, we give our space back to the 'allocator'. This is a 2875 * simplistic workaround to allow libGL.so.1 to be loaded and 2876 * unloaded multiple times. We only handle the Variant II 2877 * mechanism for now - this really needs a proper allocator. 2878 */ 2879 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 2880 == calculate_tls_end(tls_last_offset, tls_last_size)) { 2881 tls_last_offset -= obj->tlssize; 2882 tls_last_size = 0; 2883 } 2884 #endif 2885 } 2886 2887 struct tls_tcb * 2888 _rtld_allocate_tls(void) 2889 { 2890 struct tls_tcb *new_tcb; 2891 2892 wlock_acquire(); 2893 new_tcb = allocate_tls(obj_list); 2894 wlock_release(); 2895 2896 return (new_tcb); 2897 } 2898 2899 void 2900 _rtld_free_tls(struct tls_tcb *tcb) 2901 { 2902 wlock_acquire(); 2903 free_tls(tcb); 2904 wlock_release(); 2905 } 2906 2907