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 /* 296 * On entry, the dynamic linker itself has not been relocated yet. 297 * Be very careful not to reference any global data until after 298 * init_rtld has returned. It is OK to reference file-scope statics 299 * and string constants, and to call static and global functions. 300 */ 301 302 /* Find the auxiliary vector on the stack. */ 303 argc = *sp++; 304 argv = (char **) sp; 305 sp += argc + 1; /* Skip over arguments and NULL terminator */ 306 env = (char **) sp; 307 308 /* 309 * If we aren't already resident we have to dig out some more info. 310 * Note that auxinfo does not exist when we are resident. 311 * 312 * I'm not sure about the ld_resident check. It seems to read zero 313 * prior to relocation, which is what we want. When running from a 314 * resident copy everything will be relocated so we are definitely 315 * good there. 316 */ 317 if (ld_resident == 0) { 318 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 319 ; 320 aux = (Elf_Auxinfo *) sp; 321 322 /* Digest the auxiliary vector. */ 323 for (i = 0; i < AT_COUNT; i++) 324 aux_info[i] = NULL; 325 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 326 if (auxp->a_type < AT_COUNT) 327 aux_info[auxp->a_type] = auxp; 328 } 329 330 /* Initialize and relocate ourselves. */ 331 assert(aux_info[AT_BASE] != NULL); 332 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 333 } 334 335 ld_index = 0; /* don't use old env cache in case we are resident */ 336 __progname = obj_rtld.path; 337 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 338 environ = env; 339 340 trust = (geteuid() == getuid()) && (getegid() == getgid()); 341 342 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 343 if (trust) { 344 ld_debug = _getenv_ld("LD_DEBUG"); 345 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 346 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 347 } 348 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 349 350 if (ld_debug != NULL && *ld_debug != '\0') 351 debug = 1; 352 dbg("%s is initialized, base address = %p", __progname, 353 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 354 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 355 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 356 357 /* 358 * If we are resident we can skip work that we have already done. 359 * Note that the stack is reset and there is no Elf_Auxinfo 360 * when running from a resident image, and the static globals setup 361 * between here and resident_skip will have already been setup. 362 */ 363 if (ld_resident) 364 goto resident_skip1; 365 366 /* 367 * Load the main program, or process its program header if it is 368 * already loaded. 369 */ 370 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 371 int fd = aux_info[AT_EXECFD]->a_un.a_val; 372 dbg("loading main program"); 373 obj_main = map_object(fd, argv0, NULL); 374 close(fd); 375 if (obj_main == NULL) 376 die(); 377 } else { /* Main program already loaded. */ 378 const Elf_Phdr *phdr; 379 int phnum; 380 caddr_t entry; 381 382 dbg("processing main program's program header"); 383 assert(aux_info[AT_PHDR] != NULL); 384 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 385 assert(aux_info[AT_PHNUM] != NULL); 386 phnum = aux_info[AT_PHNUM]->a_un.a_val; 387 assert(aux_info[AT_PHENT] != NULL); 388 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 389 assert(aux_info[AT_ENTRY] != NULL); 390 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 391 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 392 die(); 393 } 394 395 obj_main->path = xstrdup(argv0); 396 obj_main->mainprog = true; 397 398 /* 399 * Get the actual dynamic linker pathname from the executable if 400 * possible. (It should always be possible.) That ensures that 401 * gdb will find the right dynamic linker even if a non-standard 402 * one is being used. 403 */ 404 if (obj_main->interp != NULL && 405 strcmp(obj_main->interp, obj_rtld.path) != 0) { 406 free(obj_rtld.path); 407 obj_rtld.path = xstrdup(obj_main->interp); 408 __progname = obj_rtld.path; 409 } 410 411 digest_dynamic(obj_main, 0); 412 413 linkmap_add(obj_main); 414 linkmap_add(&obj_rtld); 415 416 /* Link the main program into the list of objects. */ 417 *obj_tail = obj_main; 418 obj_tail = &obj_main->next; 419 obj_count++; 420 obj_main->refcount++; 421 /* Make sure we don't call the main program's init and fini functions. */ 422 obj_main->init = obj_main->fini = NULL; 423 424 /* Initialize a fake symbol for resolving undefined weak references. */ 425 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 426 sym_zero.st_shndx = SHN_ABS; 427 428 dbg("loading LD_PRELOAD libraries"); 429 if (load_preload_objects() == -1) 430 die(); 431 preload_tail = obj_tail; 432 433 dbg("loading needed objects"); 434 if (load_needed_objects(obj_main) == -1) 435 die(); 436 437 /* Make a list of all objects loaded at startup. */ 438 for (obj = obj_list; obj != NULL; obj = obj->next) 439 objlist_push_tail(&list_main, obj); 440 441 resident_skip1: 442 443 if (ld_tracing) { /* We're done */ 444 trace_loaded_objects(obj_main); 445 exit(0); 446 } 447 448 if (ld_resident) /* XXX clean this up! */ 449 goto resident_skip2; 450 451 if (getenv("LD_DUMP_REL_PRE") != NULL) { 452 dump_relocations(obj_main); 453 exit (0); 454 } 455 456 /* setup TLS for main thread */ 457 dbg("initializing initial thread local storage"); 458 STAILQ_FOREACH(entry, &list_main, link) { 459 /* 460 * Allocate all the initial objects out of the static TLS 461 * block even if they didn't ask for it. 462 */ 463 allocate_tls_offset(entry->obj); 464 } 465 466 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 467 468 /* 469 * Do not try to allocate the TLS here, let libc do it itself. 470 * (crt1 for the program will call _init_tls()) 471 */ 472 473 if (relocate_objects(obj_main, 474 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 475 die(); 476 477 dbg("doing copy relocations"); 478 if (do_copy_relocations(obj_main) == -1) 479 die(); 480 481 resident_skip2: 482 483 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 484 if (exec_sys_unregister(-1) < 0) { 485 dbg("exec_sys_unregister failed %d\n", errno); 486 exit(errno); 487 } 488 dbg("exec_sys_unregister success\n"); 489 exit(0); 490 } 491 492 if (getenv("LD_DUMP_REL_POST") != NULL) { 493 dump_relocations(obj_main); 494 exit (0); 495 } 496 497 dbg("initializing key program variables"); 498 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 499 set_program_var("environ", env); 500 501 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 502 extern void resident_start(void); 503 ld_resident = 1; 504 if (exec_sys_register(resident_start) < 0) { 505 dbg("exec_sys_register failed %d\n", errno); 506 exit(errno); 507 } 508 dbg("exec_sys_register success\n"); 509 exit(0); 510 } 511 512 dbg("initializing thread locks"); 513 lockdflt_init(&lockinfo); 514 lockinfo.thelock = lockinfo.lock_create(lockinfo.context); 515 516 /* Make a list of init functions to call. */ 517 objlist_init(&initlist); 518 initlist_add_objects(obj_list, preload_tail, &initlist); 519 520 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 521 522 /* 523 * Do NOT call the initlist here, give libc a chance to set up 524 * the initial TLS segment. crt1 will then call _rtld_call_init(). 525 */ 526 527 dbg("transferring control to program entry point = %p", obj_main->entry); 528 529 /* Return the exit procedure and the program entry point. */ 530 *exit_proc = rtld_exit; 531 *objp = obj_main; 532 return (func_ptr_type) obj_main->entry; 533 } 534 535 /* 536 * Call the initialization list for dynamically loaded libraries. 537 * (called from crt1.c). 538 */ 539 void 540 _rtld_call_init(void) 541 { 542 objlist_call_init(&initlist); 543 wlock_acquire(); 544 objlist_clear(&initlist); 545 wlock_release(); 546 } 547 548 Elf_Addr 549 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 550 { 551 const Elf_Rel *rel; 552 const Elf_Sym *def; 553 const Obj_Entry *defobj; 554 Elf_Addr *where; 555 Elf_Addr target; 556 int do_reloc = 1; 557 558 rlock_acquire(); 559 if (obj->pltrel) 560 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 561 else 562 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 563 564 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 565 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 566 if (def == NULL) 567 die(); 568 569 target = (Elf_Addr)(defobj->relocbase + def->st_value); 570 571 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 572 defobj->strtab + def->st_name, basename(obj->path), 573 (void *)target, basename(defobj->path)); 574 rlock_release(); 575 576 /* 577 * If we have a function call tracing hook, and the 578 * hook would like to keep tracing this one function, 579 * prevent the relocation so we will wind up here 580 * the next time again. 581 * 582 * We don't want to functrace calls from the functracer 583 * to avoid recursive loops. 584 */ 585 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 586 if (rtld_functrace(obj->path, 587 defobj->path, 588 defobj->strtab + def->st_name, 589 stack)) 590 do_reloc = 0; 591 } 592 593 if (do_reloc) 594 reloc_jmpslot(where, target); 595 return target; 596 } 597 598 /* 599 * Error reporting function. Use it like printf. If formats the message 600 * into a buffer, and sets things up so that the next call to dlerror() 601 * will return the message. 602 */ 603 void 604 _rtld_error(const char *fmt, ...) 605 { 606 static char buf[512]; 607 va_list ap; 608 609 va_start(ap, fmt); 610 vsnprintf(buf, sizeof buf, fmt, ap); 611 error_message = buf; 612 va_end(ap); 613 } 614 615 /* 616 * Return a dynamically-allocated copy of the current error message, if any. 617 */ 618 static char * 619 errmsg_save(void) 620 { 621 return error_message == NULL ? NULL : xstrdup(error_message); 622 } 623 624 /* 625 * Restore the current error message from a copy which was previously saved 626 * by errmsg_save(). The copy is freed. 627 */ 628 static void 629 errmsg_restore(char *saved_msg) 630 { 631 if (saved_msg == NULL) 632 error_message = NULL; 633 else { 634 _rtld_error("%s", saved_msg); 635 free(saved_msg); 636 } 637 } 638 639 const char * 640 basename(const char *name) 641 { 642 const char *p = strrchr(name, '/'); 643 return p != NULL ? p + 1 : name; 644 } 645 646 static void 647 die(void) 648 { 649 const char *msg = dlerror(); 650 651 if (msg == NULL) 652 msg = "Fatal error"; 653 errx(1, "%s", msg); 654 } 655 656 /* 657 * Process a shared object's DYNAMIC section, and save the important 658 * information in its Obj_Entry structure. 659 */ 660 static void 661 digest_dynamic(Obj_Entry *obj, int early) 662 { 663 const Elf_Dyn *dynp; 664 Needed_Entry **needed_tail = &obj->needed; 665 const Elf_Dyn *dyn_rpath = NULL; 666 int plttype = DT_REL; 667 668 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 669 switch (dynp->d_tag) { 670 671 case DT_REL: 672 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 673 break; 674 675 case DT_RELSZ: 676 obj->relsize = dynp->d_un.d_val; 677 break; 678 679 case DT_RELENT: 680 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 681 break; 682 683 case DT_JMPREL: 684 obj->pltrel = (const Elf_Rel *) 685 (obj->relocbase + dynp->d_un.d_ptr); 686 break; 687 688 case DT_PLTRELSZ: 689 obj->pltrelsize = dynp->d_un.d_val; 690 break; 691 692 case DT_RELA: 693 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 694 break; 695 696 case DT_RELASZ: 697 obj->relasize = dynp->d_un.d_val; 698 break; 699 700 case DT_RELAENT: 701 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 702 break; 703 704 case DT_PLTREL: 705 plttype = dynp->d_un.d_val; 706 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 707 break; 708 709 case DT_SYMTAB: 710 obj->symtab = (const Elf_Sym *) 711 (obj->relocbase + dynp->d_un.d_ptr); 712 break; 713 714 case DT_SYMENT: 715 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 716 break; 717 718 case DT_STRTAB: 719 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 720 break; 721 722 case DT_STRSZ: 723 obj->strsize = dynp->d_un.d_val; 724 break; 725 726 case DT_HASH: 727 { 728 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 729 (obj->relocbase + dynp->d_un.d_ptr); 730 obj->nbuckets = hashtab[0]; 731 obj->nchains = hashtab[1]; 732 obj->buckets = hashtab + 2; 733 obj->chains = obj->buckets + obj->nbuckets; 734 } 735 break; 736 737 case DT_NEEDED: 738 if (!obj->rtld) { 739 Needed_Entry *nep = NEW(Needed_Entry); 740 nep->name = dynp->d_un.d_val; 741 nep->obj = NULL; 742 nep->next = NULL; 743 744 *needed_tail = nep; 745 needed_tail = &nep->next; 746 } 747 break; 748 749 case DT_PLTGOT: 750 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 751 break; 752 753 case DT_TEXTREL: 754 obj->textrel = true; 755 break; 756 757 case DT_SYMBOLIC: 758 obj->symbolic = true; 759 break; 760 761 case DT_RPATH: 762 case DT_RUNPATH: /* XXX: process separately */ 763 /* 764 * We have to wait until later to process this, because we 765 * might not have gotten the address of the string table yet. 766 */ 767 dyn_rpath = dynp; 768 break; 769 770 case DT_SONAME: 771 /* Not used by the dynamic linker. */ 772 break; 773 774 case DT_INIT: 775 obj->init = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr); 776 break; 777 778 case DT_FINI: 779 obj->fini = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr); 780 break; 781 782 case DT_DEBUG: 783 /* XXX - not implemented yet */ 784 if (!early) 785 dbg("Filling in DT_DEBUG entry"); 786 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 787 break; 788 789 case DT_FLAGS: 790 if (dynp->d_un.d_val & DF_ORIGIN) { 791 obj->origin_path = xmalloc(PATH_MAX); 792 if (rtld_dirname(obj->path, obj->origin_path) == -1) 793 die(); 794 } 795 if (dynp->d_un.d_val & DF_SYMBOLIC) 796 obj->symbolic = true; 797 if (dynp->d_un.d_val & DF_TEXTREL) 798 obj->textrel = true; 799 if (dynp->d_un.d_val & DF_BIND_NOW) 800 obj->bind_now = true; 801 if (dynp->d_un.d_val & DF_STATIC_TLS) 802 ; 803 break; 804 805 default: 806 if (!early) 807 dbg("Ignoring d_tag %d = %#x", dynp->d_tag, dynp->d_tag); 808 break; 809 } 810 } 811 812 obj->traced = false; 813 814 if (plttype == DT_RELA) { 815 obj->pltrela = (const Elf_Rela *) obj->pltrel; 816 obj->pltrel = NULL; 817 obj->pltrelasize = obj->pltrelsize; 818 obj->pltrelsize = 0; 819 } 820 821 if (dyn_rpath != NULL) 822 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val; 823 } 824 825 /* 826 * Process a shared object's program header. This is used only for the 827 * main program, when the kernel has already loaded the main program 828 * into memory before calling the dynamic linker. It creates and 829 * returns an Obj_Entry structure. 830 */ 831 static Obj_Entry * 832 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 833 { 834 Obj_Entry *obj; 835 const Elf_Phdr *phlimit = phdr + phnum; 836 const Elf_Phdr *ph; 837 int nsegs = 0; 838 839 obj = obj_new(); 840 for (ph = phdr; ph < phlimit; ph++) { 841 switch (ph->p_type) { 842 843 case PT_PHDR: 844 if ((const Elf_Phdr *)ph->p_vaddr != phdr) { 845 _rtld_error("%s: invalid PT_PHDR", path); 846 return NULL; 847 } 848 obj->phdr = (const Elf_Phdr *) ph->p_vaddr; 849 obj->phsize = ph->p_memsz; 850 break; 851 852 case PT_INTERP: 853 obj->interp = (const char *) ph->p_vaddr; 854 break; 855 856 case PT_LOAD: 857 if (nsegs == 0) { /* First load segment */ 858 obj->vaddrbase = trunc_page(ph->p_vaddr); 859 obj->mapbase = (caddr_t) obj->vaddrbase; 860 obj->relocbase = obj->mapbase - obj->vaddrbase; 861 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 862 obj->vaddrbase; 863 } else { /* Last load segment */ 864 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 865 obj->vaddrbase; 866 } 867 nsegs++; 868 break; 869 870 case PT_DYNAMIC: 871 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; 872 break; 873 874 case PT_TLS: 875 obj->tlsindex = 1; 876 obj->tlssize = ph->p_memsz; 877 obj->tlsalign = ph->p_align; 878 obj->tlsinitsize = ph->p_filesz; 879 obj->tlsinit = (void*) ph->p_vaddr; 880 break; 881 } 882 } 883 if (nsegs < 1) { 884 _rtld_error("%s: too few PT_LOAD segments", path); 885 return NULL; 886 } 887 888 obj->entry = entry; 889 return obj; 890 } 891 892 static Obj_Entry * 893 dlcheck(void *handle) 894 { 895 Obj_Entry *obj; 896 897 for (obj = obj_list; obj != NULL; obj = obj->next) 898 if (obj == (Obj_Entry *) handle) 899 break; 900 901 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 902 _rtld_error("Invalid shared object handle %p", handle); 903 return NULL; 904 } 905 return obj; 906 } 907 908 /* 909 * If the given object is already in the donelist, return true. Otherwise 910 * add the object to the list and return false. 911 */ 912 static bool 913 donelist_check(DoneList *dlp, const Obj_Entry *obj) 914 { 915 unsigned int i; 916 917 for (i = 0; i < dlp->num_used; i++) 918 if (dlp->objs[i] == obj) 919 return true; 920 /* 921 * Our donelist allocation should always be sufficient. But if 922 * our threads locking isn't working properly, more shared objects 923 * could have been loaded since we allocated the list. That should 924 * never happen, but we'll handle it properly just in case it does. 925 */ 926 if (dlp->num_used < dlp->num_alloc) 927 dlp->objs[dlp->num_used++] = obj; 928 return false; 929 } 930 931 /* 932 * Hash function for symbol table lookup. Don't even think about changing 933 * this. It is specified by the System V ABI. 934 */ 935 unsigned long 936 elf_hash(const char *name) 937 { 938 const unsigned char *p = (const unsigned char *) name; 939 unsigned long h = 0; 940 unsigned long g; 941 942 while (*p != '\0') { 943 h = (h << 4) + *p++; 944 if ((g = h & 0xf0000000) != 0) 945 h ^= g >> 24; 946 h &= ~g; 947 } 948 return h; 949 } 950 951 /* 952 * Find the library with the given name, and return its full pathname. 953 * The returned string is dynamically allocated. Generates an error 954 * message and returns NULL if the library cannot be found. 955 * 956 * If the second argument is non-NULL, then it refers to an already- 957 * loaded shared object, whose library search path will be searched. 958 * 959 * The search order is: 960 * LD_LIBRARY_PATH 961 * rpath in the referencing file 962 * ldconfig hints 963 * /usr/lib 964 */ 965 static char * 966 find_library(const char *name, const Obj_Entry *refobj) 967 { 968 char *pathname; 969 970 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 971 if (name[0] != '/' && !trust) { 972 _rtld_error("Absolute pathname required for shared object \"%s\"", 973 name); 974 return NULL; 975 } 976 return xstrdup(name); 977 } 978 979 dbg(" Searching for \"%s\"", name); 980 981 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 982 (refobj != NULL && 983 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 984 (pathname = search_library_path(name, gethints())) != NULL || 985 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 986 return pathname; 987 988 if(refobj != NULL && refobj->path != NULL) { 989 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 990 name, basename(refobj->path)); 991 } else { 992 _rtld_error("Shared object \"%s\" not found", name); 993 } 994 return NULL; 995 } 996 997 /* 998 * Given a symbol number in a referencing object, find the corresponding 999 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1000 * no definition was found. Returns a pointer to the Obj_Entry of the 1001 * defining object via the reference parameter DEFOBJ_OUT. 1002 */ 1003 const Elf_Sym * 1004 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1005 const Obj_Entry **defobj_out, bool in_plt, SymCache *cache) 1006 { 1007 const Elf_Sym *ref; 1008 const Elf_Sym *def; 1009 const Obj_Entry *defobj; 1010 const char *name; 1011 unsigned long hash; 1012 1013 /* 1014 * If we have already found this symbol, get the information from 1015 * the cache. 1016 */ 1017 if (symnum >= refobj->nchains) 1018 return NULL; /* Bad object */ 1019 if (cache != NULL && cache[symnum].sym != NULL) { 1020 *defobj_out = cache[symnum].obj; 1021 return cache[symnum].sym; 1022 } 1023 1024 ref = refobj->symtab + symnum; 1025 name = refobj->strtab + ref->st_name; 1026 defobj = NULL; 1027 1028 /* 1029 * We don't have to do a full scale lookup if the symbol is local. 1030 * We know it will bind to the instance in this load module; to 1031 * which we already have a pointer (ie ref). By not doing a lookup, 1032 * we not only improve performance, but it also avoids unresolvable 1033 * symbols when local symbols are not in the hash table. 1034 * 1035 * This might occur for TLS module relocations, which simply use 1036 * symbol 0. 1037 */ 1038 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1039 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1040 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1041 symnum); 1042 } 1043 hash = elf_hash(name); 1044 def = symlook_default(name, hash, refobj, &defobj, in_plt); 1045 } else { 1046 def = ref; 1047 defobj = refobj; 1048 } 1049 1050 /* 1051 * If we found no definition and the reference is weak, treat the 1052 * symbol as having the value zero. 1053 */ 1054 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1055 def = &sym_zero; 1056 defobj = obj_main; 1057 } 1058 1059 if (def != NULL) { 1060 *defobj_out = defobj; 1061 /* Record the information in the cache to avoid subsequent lookups. */ 1062 if (cache != NULL) { 1063 cache[symnum].sym = def; 1064 cache[symnum].obj = defobj; 1065 } 1066 } else 1067 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1068 return def; 1069 } 1070 1071 /* 1072 * Return the search path from the ldconfig hints file, reading it if 1073 * necessary. Returns NULL if there are problems with the hints file, 1074 * or if the search path there is empty. 1075 */ 1076 static const char * 1077 gethints(void) 1078 { 1079 static char *hints; 1080 1081 if (hints == NULL) { 1082 int fd; 1083 struct elfhints_hdr hdr; 1084 char *p; 1085 1086 /* Keep from trying again in case the hints file is bad. */ 1087 hints = ""; 1088 1089 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1) 1090 return NULL; 1091 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1092 hdr.magic != ELFHINTS_MAGIC || 1093 hdr.version != 1) { 1094 close(fd); 1095 return NULL; 1096 } 1097 p = xmalloc(hdr.dirlistlen + 1); 1098 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1099 read(fd, p, hdr.dirlistlen + 1) != hdr.dirlistlen + 1) { 1100 free(p); 1101 close(fd); 1102 return NULL; 1103 } 1104 hints = p; 1105 close(fd); 1106 } 1107 return hints[0] != '\0' ? hints : NULL; 1108 } 1109 1110 static void 1111 init_dag(Obj_Entry *root) 1112 { 1113 DoneList donelist; 1114 1115 donelist_init(&donelist); 1116 init_dag1(root, root, &donelist); 1117 } 1118 1119 static void 1120 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1121 { 1122 const Needed_Entry *needed; 1123 1124 if (donelist_check(dlp, obj)) 1125 return; 1126 objlist_push_tail(&obj->dldags, root); 1127 objlist_push_tail(&root->dagmembers, obj); 1128 for (needed = obj->needed; needed != NULL; needed = needed->next) 1129 if (needed->obj != NULL) 1130 init_dag1(root, needed->obj, dlp); 1131 } 1132 1133 /* 1134 * Initialize the dynamic linker. The argument is the address at which 1135 * the dynamic linker has been mapped into memory. The primary task of 1136 * this function is to relocate the dynamic linker. 1137 */ 1138 static void 1139 init_rtld(caddr_t mapbase) 1140 { 1141 Obj_Entry objtmp; /* Temporary rtld object */ 1142 1143 /* 1144 * Conjure up an Obj_Entry structure for the dynamic linker. 1145 * 1146 * The "path" member can't be initialized yet because string constatns 1147 * cannot yet be acessed. Below we will set it correctly. 1148 */ 1149 memset(&objtmp, 0, sizeof(objtmp)); 1150 objtmp.path = NULL; 1151 objtmp.rtld = true; 1152 objtmp.mapbase = mapbase; 1153 #ifdef PIC 1154 objtmp.relocbase = mapbase; 1155 #endif 1156 if (&_DYNAMIC != 0) { 1157 objtmp.dynamic = rtld_dynamic(&objtmp); 1158 digest_dynamic(&objtmp, 1); 1159 assert(objtmp.needed == NULL); 1160 assert(!objtmp.textrel); 1161 1162 /* 1163 * Temporarily put the dynamic linker entry into the object list, so 1164 * that symbols can be found. 1165 */ 1166 1167 relocate_objects(&objtmp, true, &objtmp); 1168 } 1169 1170 /* Initialize the object list. */ 1171 obj_tail = &obj_list; 1172 1173 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1174 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1175 1176 /* Replace the path with a dynamically allocated copy. */ 1177 obj_rtld.path = xstrdup(PATH_RTLD); 1178 1179 r_debug.r_brk = r_debug_state; 1180 r_debug.r_state = RT_CONSISTENT; 1181 } 1182 1183 /* 1184 * Add the init functions from a needed object list (and its recursive 1185 * needed objects) to "list". This is not used directly; it is a helper 1186 * function for initlist_add_objects(). The write lock must be held 1187 * when this function is called. 1188 */ 1189 static void 1190 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1191 { 1192 /* Recursively process the successor needed objects. */ 1193 if (needed->next != NULL) 1194 initlist_add_neededs(needed->next, list); 1195 1196 /* Process the current needed object. */ 1197 if (needed->obj != NULL) 1198 initlist_add_objects(needed->obj, &needed->obj->next, list); 1199 } 1200 1201 /* 1202 * Scan all of the DAGs rooted in the range of objects from "obj" to 1203 * "tail" and add their init functions to "list". This recurses over 1204 * the DAGs and ensure the proper init ordering such that each object's 1205 * needed libraries are initialized before the object itself. At the 1206 * same time, this function adds the objects to the global finalization 1207 * list "list_fini" in the opposite order. The write lock must be 1208 * held when this function is called. 1209 */ 1210 static void 1211 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1212 { 1213 if (obj->init_done) 1214 return; 1215 obj->init_done = true; 1216 1217 /* Recursively process the successor objects. */ 1218 if (&obj->next != tail) 1219 initlist_add_objects(obj->next, tail, list); 1220 1221 /* Recursively process the needed objects. */ 1222 if (obj->needed != NULL) 1223 initlist_add_neededs(obj->needed, list); 1224 1225 /* Add the object to the init list. */ 1226 if (obj->init != NULL) 1227 objlist_push_tail(list, obj); 1228 1229 /* Add the object to the global fini list in the reverse order. */ 1230 if (obj->fini != NULL) 1231 objlist_push_head(&list_fini, obj); 1232 } 1233 1234 static bool 1235 is_exported(const Elf_Sym *def) 1236 { 1237 Elf_Addr value; 1238 const func_ptr_type *p; 1239 1240 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1241 for (p = exports; *p != NULL; p++) { 1242 if ((Elf_Addr)(*p) == value) 1243 return true; 1244 } 1245 return false; 1246 } 1247 1248 /* 1249 * Given a shared object, traverse its list of needed objects, and load 1250 * each of them. Returns 0 on success. Generates an error message and 1251 * returns -1 on failure. 1252 */ 1253 static int 1254 load_needed_objects(Obj_Entry *first) 1255 { 1256 Obj_Entry *obj; 1257 1258 for (obj = first; obj != NULL; obj = obj->next) { 1259 Needed_Entry *needed; 1260 1261 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1262 const char *name = obj->strtab + needed->name; 1263 char *path = find_library(name, obj); 1264 1265 needed->obj = NULL; 1266 if (path == NULL && !ld_tracing) 1267 return -1; 1268 1269 if (path) { 1270 needed->obj = load_object(path); 1271 if (needed->obj == NULL && !ld_tracing) 1272 return -1; /* XXX - cleanup */ 1273 } 1274 } 1275 } 1276 1277 return 0; 1278 } 1279 1280 #define RTLD_FUNCTRACE "_rtld_functrace" 1281 1282 static int 1283 load_preload_objects(void) 1284 { 1285 char *p = ld_preload; 1286 static const char delim[] = " \t:;"; 1287 1288 if (p == NULL) 1289 return 0; 1290 1291 p += strspn(p, delim); 1292 while (*p != '\0') { 1293 size_t len = strcspn(p, delim); 1294 char *path; 1295 char savech; 1296 Obj_Entry *obj; 1297 const Elf_Sym *sym; 1298 1299 savech = p[len]; 1300 p[len] = '\0'; 1301 if ((path = find_library(p, NULL)) == NULL) 1302 return -1; 1303 obj = load_object(path); 1304 if (obj == NULL) 1305 return -1; /* XXX - cleanup */ 1306 p[len] = savech; 1307 p += len; 1308 p += strspn(p, delim); 1309 1310 /* Check for the magic tracing function */ 1311 sym = symlook_obj(RTLD_FUNCTRACE, elf_hash(RTLD_FUNCTRACE), obj, true); 1312 if (sym != NULL) { 1313 rtld_functrace = (void *)(obj->relocbase + sym->st_value); 1314 rtld_functrace_obj = obj; 1315 } 1316 } 1317 return 0; 1318 } 1319 1320 /* 1321 * Returns a pointer to the Obj_Entry for the object with the given path. 1322 * Returns NULL if no matching object was found. 1323 */ 1324 static Obj_Entry * 1325 find_object(const char *path) 1326 { 1327 Obj_Entry *obj; 1328 1329 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1330 if (strcmp(obj->path, path) == 0) 1331 return(obj); 1332 } 1333 return(NULL); 1334 } 1335 1336 /* 1337 * Returns a pointer to the Obj_Entry for the object matching device and 1338 * inode of the given path. If no matching object was found, the descriptor 1339 * is returned in fd. 1340 * Returns with obj == NULL && fd == -1 on error. 1341 */ 1342 static Obj_Entry * 1343 find_object2(const char *path, int *fd, struct stat *sb) 1344 { 1345 Obj_Entry *obj; 1346 1347 if ((*fd = open(path, O_RDONLY)) == -1) { 1348 _rtld_error("Cannot open \"%s\"", path); 1349 return(NULL); 1350 } 1351 1352 if (fstat(*fd, sb) == -1) { 1353 _rtld_error("Cannot fstat \"%s\"", path); 1354 close(*fd); 1355 *fd = -1; 1356 return NULL; 1357 } 1358 1359 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1360 if (obj->ino == sb->st_ino && obj->dev == sb->st_dev) { 1361 close(*fd); 1362 break; 1363 } 1364 } 1365 1366 return(obj); 1367 } 1368 1369 /* 1370 * Load a shared object into memory, if it is not already loaded. The 1371 * argument must be a string allocated on the heap. This function assumes 1372 * responsibility for freeing it when necessary. 1373 * 1374 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1375 * on failure. 1376 */ 1377 static Obj_Entry * 1378 load_object(char *path) 1379 { 1380 Obj_Entry *obj; 1381 int fd = -1; 1382 struct stat sb; 1383 1384 obj = find_object(path); 1385 if (obj != NULL) { 1386 obj->refcount++; 1387 free(path); 1388 return(obj); 1389 } 1390 1391 obj = find_object2(path, &fd, &sb); 1392 if (obj != NULL) { 1393 obj->refcount++; 1394 free(path); 1395 return(obj); 1396 } else if (fd == -1) { 1397 free(path); 1398 return(NULL); 1399 } 1400 1401 dbg("loading \"%s\"", path); 1402 obj = map_object(fd, path, &sb); 1403 close(fd); 1404 if (obj == NULL) { 1405 free(path); 1406 return NULL; 1407 } 1408 1409 obj->path = path; 1410 digest_dynamic(obj, 0); 1411 1412 *obj_tail = obj; 1413 obj_tail = &obj->next; 1414 obj_count++; 1415 linkmap_add(obj); /* for GDB & dlinfo() */ 1416 1417 dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1, 1418 obj->path); 1419 if (obj->textrel) 1420 dbg(" WARNING: %s has impure text", obj->path); 1421 1422 obj->refcount++; 1423 return obj; 1424 } 1425 1426 /* 1427 * Check for locking violations and die if one is found. 1428 */ 1429 static void 1430 lock_check(void) 1431 { 1432 int rcount, wcount; 1433 1434 rcount = lockinfo.rcount; 1435 wcount = lockinfo.wcount; 1436 assert(rcount >= 0); 1437 assert(wcount >= 0); 1438 if (wcount > 1 || (wcount != 0 && rcount != 0)) { 1439 _rtld_error("Application locking error: %d readers and %d writers" 1440 " in dynamic linker. See DLLOCKINIT(3) in manual pages.", 1441 rcount, wcount); 1442 die(); 1443 } 1444 } 1445 1446 static Obj_Entry * 1447 obj_from_addr(const void *addr) 1448 { 1449 Obj_Entry *obj; 1450 1451 for (obj = obj_list; obj != NULL; obj = obj->next) { 1452 if (addr < (void *) obj->mapbase) 1453 continue; 1454 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1455 return obj; 1456 } 1457 return NULL; 1458 } 1459 1460 /* 1461 * Call the finalization functions for each of the objects in "list" 1462 * which are unreferenced. All of the objects are expected to have 1463 * non-NULL fini functions. 1464 */ 1465 static void 1466 objlist_call_fini(Objlist *list) 1467 { 1468 Objlist_Entry *elm; 1469 char *saved_msg; 1470 1471 /* 1472 * Preserve the current error message since a fini function might 1473 * call into the dynamic linker and overwrite it. 1474 */ 1475 saved_msg = errmsg_save(); 1476 STAILQ_FOREACH(elm, list, link) { 1477 if (elm->obj->refcount == 0) { 1478 dbg("calling fini function for %s", elm->obj->path); 1479 (*elm->obj->fini)(); 1480 } 1481 } 1482 errmsg_restore(saved_msg); 1483 } 1484 1485 /* 1486 * Call the initialization functions for each of the objects in 1487 * "list". All of the objects are expected to have non-NULL init 1488 * functions. 1489 */ 1490 static void 1491 objlist_call_init(Objlist *list) 1492 { 1493 Objlist_Entry *elm; 1494 char *saved_msg; 1495 1496 /* 1497 * Preserve the current error message since an init function might 1498 * call into the dynamic linker and overwrite it. 1499 */ 1500 saved_msg = errmsg_save(); 1501 STAILQ_FOREACH(elm, list, link) { 1502 dbg("calling init function for %s", elm->obj->path); 1503 (*elm->obj->init)(); 1504 } 1505 errmsg_restore(saved_msg); 1506 } 1507 1508 static void 1509 objlist_clear(Objlist *list) 1510 { 1511 Objlist_Entry *elm; 1512 1513 while (!STAILQ_EMPTY(list)) { 1514 elm = STAILQ_FIRST(list); 1515 STAILQ_REMOVE_HEAD(list, link); 1516 free(elm); 1517 } 1518 } 1519 1520 static Objlist_Entry * 1521 objlist_find(Objlist *list, const Obj_Entry *obj) 1522 { 1523 Objlist_Entry *elm; 1524 1525 STAILQ_FOREACH(elm, list, link) 1526 if (elm->obj == obj) 1527 return elm; 1528 return NULL; 1529 } 1530 1531 static void 1532 objlist_init(Objlist *list) 1533 { 1534 STAILQ_INIT(list); 1535 } 1536 1537 static void 1538 objlist_push_head(Objlist *list, Obj_Entry *obj) 1539 { 1540 Objlist_Entry *elm; 1541 1542 elm = NEW(Objlist_Entry); 1543 elm->obj = obj; 1544 STAILQ_INSERT_HEAD(list, elm, link); 1545 } 1546 1547 static void 1548 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1549 { 1550 Objlist_Entry *elm; 1551 1552 elm = NEW(Objlist_Entry); 1553 elm->obj = obj; 1554 STAILQ_INSERT_TAIL(list, elm, link); 1555 } 1556 1557 static void 1558 objlist_remove(Objlist *list, Obj_Entry *obj) 1559 { 1560 Objlist_Entry *elm; 1561 1562 if ((elm = objlist_find(list, obj)) != NULL) { 1563 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1564 free(elm); 1565 } 1566 } 1567 1568 /* 1569 * Remove all of the unreferenced objects from "list". 1570 */ 1571 static void 1572 objlist_remove_unref(Objlist *list) 1573 { 1574 Objlist newlist; 1575 Objlist_Entry *elm; 1576 1577 STAILQ_INIT(&newlist); 1578 while (!STAILQ_EMPTY(list)) { 1579 elm = STAILQ_FIRST(list); 1580 STAILQ_REMOVE_HEAD(list, link); 1581 if (elm->obj->refcount == 0) 1582 free(elm); 1583 else 1584 STAILQ_INSERT_TAIL(&newlist, elm, link); 1585 } 1586 *list = newlist; 1587 } 1588 1589 /* 1590 * Relocate newly-loaded shared objects. The argument is a pointer to 1591 * the Obj_Entry for the first such object. All objects from the first 1592 * to the end of the list of objects are relocated. Returns 0 on success, 1593 * or -1 on failure. 1594 */ 1595 static int 1596 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1597 { 1598 Obj_Entry *obj; 1599 1600 for (obj = first; obj != NULL; obj = obj->next) { 1601 if (obj != rtldobj) 1602 dbg("relocating \"%s\"", obj->path); 1603 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1604 obj->symtab == NULL || obj->strtab == NULL) { 1605 _rtld_error("%s: Shared object has no run-time symbol table", 1606 obj->path); 1607 return -1; 1608 } 1609 1610 if (obj->textrel) { 1611 /* There are relocations to the write-protected text segment. */ 1612 if (mprotect(obj->mapbase, obj->textsize, 1613 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1614 _rtld_error("%s: Cannot write-enable text segment: %s", 1615 obj->path, strerror(errno)); 1616 return -1; 1617 } 1618 } 1619 1620 /* Process the non-PLT relocations. */ 1621 if (reloc_non_plt(obj, rtldobj)) 1622 return -1; 1623 1624 /* 1625 * Reprotect the text segment. Make sure it is included in the 1626 * core dump since we modified it. This unfortunately causes the 1627 * entire text segment to core-out but we don't have much of a 1628 * choice. We could try to only reenable core dumps on pages 1629 * in which relocations occured but that is likely most of the text 1630 * pages anyway, and even that would not work because the rest of 1631 * the text pages would wind up as a read-only OBJT_DEFAULT object 1632 * (created due to our modifications) backed by the original OBJT_VNODE 1633 * object, and the ELF coredump code is currently only able to dump 1634 * vnode records for pure vnode-backed mappings, not vnode backings 1635 * to memory objects. 1636 */ 1637 if (obj->textrel) { 1638 madvise(obj->mapbase, obj->textsize, MADV_CORE); 1639 if (mprotect(obj->mapbase, obj->textsize, 1640 PROT_READ|PROT_EXEC) == -1) { 1641 _rtld_error("%s: Cannot write-protect text segment: %s", 1642 obj->path, strerror(errno)); 1643 return -1; 1644 } 1645 } 1646 1647 /* Process the PLT relocations. */ 1648 if (reloc_plt(obj) == -1) 1649 return -1; 1650 /* Relocate the jump slots if we are doing immediate binding. */ 1651 if (obj->bind_now || bind_now) 1652 if (reloc_jmpslots(obj) == -1) 1653 return -1; 1654 1655 1656 /* 1657 * Set up the magic number and version in the Obj_Entry. These 1658 * were checked in the crt1.o from the original ElfKit, so we 1659 * set them for backward compatibility. 1660 */ 1661 obj->magic = RTLD_MAGIC; 1662 obj->version = RTLD_VERSION; 1663 1664 /* Set the special PLT or GOT entries. */ 1665 init_pltgot(obj); 1666 } 1667 1668 return 0; 1669 } 1670 1671 /* 1672 * Cleanup procedure. It will be called (by the atexit mechanism) just 1673 * before the process exits. 1674 */ 1675 static void 1676 rtld_exit(void) 1677 { 1678 Obj_Entry *obj; 1679 1680 dbg("rtld_exit()"); 1681 /* Clear all the reference counts so the fini functions will be called. */ 1682 for (obj = obj_list; obj != NULL; obj = obj->next) 1683 obj->refcount = 0; 1684 objlist_call_fini(&list_fini); 1685 /* No need to remove the items from the list, since we are exiting. */ 1686 } 1687 1688 static void * 1689 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1690 { 1691 if (path == NULL) 1692 return (NULL); 1693 1694 path += strspn(path, ":;"); 1695 while (*path != '\0') { 1696 size_t len; 1697 char *res; 1698 1699 len = strcspn(path, ":;"); 1700 res = callback(path, len, arg); 1701 1702 if (res != NULL) 1703 return (res); 1704 1705 path += len; 1706 path += strspn(path, ":;"); 1707 } 1708 1709 return (NULL); 1710 } 1711 1712 struct try_library_args { 1713 const char *name; 1714 size_t namelen; 1715 char *buffer; 1716 size_t buflen; 1717 }; 1718 1719 static void * 1720 try_library_path(const char *dir, size_t dirlen, void *param) 1721 { 1722 struct try_library_args *arg; 1723 1724 arg = param; 1725 if (*dir == '/' || trust) { 1726 char *pathname; 1727 1728 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1729 return (NULL); 1730 1731 pathname = arg->buffer; 1732 strncpy(pathname, dir, dirlen); 1733 pathname[dirlen] = '/'; 1734 strcpy(pathname + dirlen + 1, arg->name); 1735 1736 dbg(" Trying \"%s\"", pathname); 1737 if (access(pathname, F_OK) == 0) { /* We found it */ 1738 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1739 strcpy(pathname, arg->buffer); 1740 return (pathname); 1741 } 1742 } 1743 return (NULL); 1744 } 1745 1746 static char * 1747 search_library_path(const char *name, const char *path) 1748 { 1749 char *p; 1750 struct try_library_args arg; 1751 1752 if (path == NULL) 1753 return NULL; 1754 1755 arg.name = name; 1756 arg.namelen = strlen(name); 1757 arg.buffer = xmalloc(PATH_MAX); 1758 arg.buflen = PATH_MAX; 1759 1760 p = path_enumerate(path, try_library_path, &arg); 1761 1762 free(arg.buffer); 1763 1764 return (p); 1765 } 1766 1767 int 1768 dlclose(void *handle) 1769 { 1770 Obj_Entry *root; 1771 1772 wlock_acquire(); 1773 root = dlcheck(handle); 1774 if (root == NULL) { 1775 wlock_release(); 1776 return -1; 1777 } 1778 1779 /* Unreference the object and its dependencies. */ 1780 root->dl_refcount--; 1781 unref_dag(root); 1782 1783 if (root->refcount == 0) { 1784 /* 1785 * The object is no longer referenced, so we must unload it. 1786 * First, call the fini functions with no locks held. 1787 */ 1788 wlock_release(); 1789 objlist_call_fini(&list_fini); 1790 wlock_acquire(); 1791 objlist_remove_unref(&list_fini); 1792 1793 /* Finish cleaning up the newly-unreferenced objects. */ 1794 GDB_STATE(RT_DELETE,&root->linkmap); 1795 unload_object(root); 1796 GDB_STATE(RT_CONSISTENT,NULL); 1797 } 1798 wlock_release(); 1799 return 0; 1800 } 1801 1802 const char * 1803 dlerror(void) 1804 { 1805 char *msg = error_message; 1806 error_message = NULL; 1807 return msg; 1808 } 1809 1810 void * 1811 dlopen(const char *name, int mode) 1812 { 1813 Obj_Entry **old_obj_tail; 1814 Obj_Entry *obj; 1815 Objlist initlist; 1816 int result; 1817 1818 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1819 if (ld_tracing != NULL) 1820 environ = (char **)*get_program_var_addr("environ"); 1821 1822 objlist_init(&initlist); 1823 1824 wlock_acquire(); 1825 GDB_STATE(RT_ADD,NULL); 1826 1827 old_obj_tail = obj_tail; 1828 obj = NULL; 1829 if (name == NULL) { 1830 obj = obj_main; 1831 obj->refcount++; 1832 } else { 1833 char *path = find_library(name, obj_main); 1834 if (path != NULL) 1835 obj = load_object(path); 1836 } 1837 1838 if (obj) { 1839 obj->dl_refcount++; 1840 if ((mode & RTLD_GLOBAL) && objlist_find(&list_global, obj) == NULL) 1841 objlist_push_tail(&list_global, obj); 1842 mode &= RTLD_MODEMASK; 1843 if (*old_obj_tail != NULL) { /* We loaded something new. */ 1844 assert(*old_obj_tail == obj); 1845 1846 result = load_needed_objects(obj); 1847 if (result != -1 && ld_tracing) 1848 goto trace; 1849 1850 if (result == -1 || 1851 (init_dag(obj), relocate_objects(obj, mode == RTLD_NOW, 1852 &obj_rtld)) == -1) { 1853 obj->dl_refcount--; 1854 unref_dag(obj); 1855 if (obj->refcount == 0) 1856 unload_object(obj); 1857 obj = NULL; 1858 } else { 1859 /* Make list of init functions to call. */ 1860 initlist_add_objects(obj, &obj->next, &initlist); 1861 } 1862 } else if (ld_tracing) 1863 goto trace; 1864 } 1865 1866 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 1867 1868 /* Call the init functions with no locks held. */ 1869 wlock_release(); 1870 objlist_call_init(&initlist); 1871 wlock_acquire(); 1872 objlist_clear(&initlist); 1873 wlock_release(); 1874 return obj; 1875 trace: 1876 trace_loaded_objects(obj); 1877 wlock_release(); 1878 exit(0); 1879 } 1880 1881 void * 1882 dlsym(void *handle, const char *name) 1883 { 1884 const Obj_Entry *obj; 1885 unsigned long hash; 1886 const Elf_Sym *def; 1887 const Obj_Entry *defobj; 1888 1889 hash = elf_hash(name); 1890 def = NULL; 1891 defobj = NULL; 1892 1893 rlock_acquire(); 1894 if (handle == NULL || handle == RTLD_NEXT || 1895 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 1896 void *retaddr; 1897 1898 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 1899 if ((obj = obj_from_addr(retaddr)) == NULL) { 1900 _rtld_error("Cannot determine caller's shared object"); 1901 rlock_release(); 1902 return NULL; 1903 } 1904 if (handle == NULL) { /* Just the caller's shared object. */ 1905 def = symlook_obj(name, hash, obj, true); 1906 defobj = obj; 1907 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 1908 handle == RTLD_SELF) { /* ... caller included */ 1909 if (handle == RTLD_NEXT) 1910 obj = obj->next; 1911 for (; obj != NULL; obj = obj->next) { 1912 if ((def = symlook_obj(name, hash, obj, true)) != NULL) { 1913 defobj = obj; 1914 break; 1915 } 1916 } 1917 } else { 1918 assert(handle == RTLD_DEFAULT); 1919 def = symlook_default(name, hash, obj, &defobj, true); 1920 } 1921 } else { 1922 DoneList donelist; 1923 1924 if ((obj = dlcheck(handle)) == NULL) { 1925 rlock_release(); 1926 return NULL; 1927 } 1928 1929 donelist_init(&donelist); 1930 if (obj->mainprog) { 1931 /* Search main program and all libraries loaded by it. */ 1932 def = symlook_list(name, hash, &list_main, &defobj, true, 1933 &donelist); 1934 } else { 1935 Needed_Entry fake; 1936 1937 /* Search the given object and its needed objects. */ 1938 fake.next = NULL; 1939 fake.obj = (Obj_Entry *)obj; 1940 fake.name = 0; 1941 def = symlook_needed(name, hash, &fake, &defobj, true, 1942 &donelist); 1943 } 1944 } 1945 1946 if (def != NULL) { 1947 rlock_release(); 1948 return defobj->relocbase + def->st_value; 1949 } 1950 1951 _rtld_error("Undefined symbol \"%s\"", name); 1952 rlock_release(); 1953 return NULL; 1954 } 1955 1956 int 1957 dladdr(const void *addr, Dl_info *info) 1958 { 1959 const Obj_Entry *obj; 1960 const Elf_Sym *def; 1961 void *symbol_addr; 1962 unsigned long symoffset; 1963 1964 rlock_acquire(); 1965 obj = obj_from_addr(addr); 1966 if (obj == NULL) { 1967 _rtld_error("No shared object contains address"); 1968 rlock_release(); 1969 return 0; 1970 } 1971 info->dli_fname = obj->path; 1972 info->dli_fbase = obj->mapbase; 1973 info->dli_saddr = NULL; 1974 info->dli_sname = NULL; 1975 1976 /* 1977 * Walk the symbol list looking for the symbol whose address is 1978 * closest to the address sent in. 1979 */ 1980 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 1981 def = obj->symtab + symoffset; 1982 1983 /* 1984 * For skip the symbol if st_shndx is either SHN_UNDEF or 1985 * SHN_COMMON. 1986 */ 1987 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 1988 continue; 1989 1990 /* 1991 * If the symbol is greater than the specified address, or if it 1992 * is further away from addr than the current nearest symbol, 1993 * then reject it. 1994 */ 1995 symbol_addr = obj->relocbase + def->st_value; 1996 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 1997 continue; 1998 1999 /* Update our idea of the nearest symbol. */ 2000 info->dli_sname = obj->strtab + def->st_name; 2001 info->dli_saddr = symbol_addr; 2002 2003 /* Exact match? */ 2004 if (info->dli_saddr == addr) 2005 break; 2006 } 2007 rlock_release(); 2008 return 1; 2009 } 2010 2011 int 2012 dlinfo(void *handle, int request, void *p) 2013 { 2014 const Obj_Entry *obj; 2015 int error; 2016 2017 rlock_acquire(); 2018 2019 if (handle == NULL || handle == RTLD_SELF) { 2020 void *retaddr; 2021 2022 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2023 if ((obj = obj_from_addr(retaddr)) == NULL) 2024 _rtld_error("Cannot determine caller's shared object"); 2025 } else 2026 obj = dlcheck(handle); 2027 2028 if (obj == NULL) { 2029 rlock_release(); 2030 return (-1); 2031 } 2032 2033 error = 0; 2034 switch (request) { 2035 case RTLD_DI_LINKMAP: 2036 *((struct link_map const **)p) = &obj->linkmap; 2037 break; 2038 case RTLD_DI_ORIGIN: 2039 error = rtld_dirname(obj->path, p); 2040 break; 2041 2042 case RTLD_DI_SERINFOSIZE: 2043 case RTLD_DI_SERINFO: 2044 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2045 break; 2046 2047 default: 2048 _rtld_error("Invalid request %d passed to dlinfo()", request); 2049 error = -1; 2050 } 2051 2052 rlock_release(); 2053 2054 return (error); 2055 } 2056 2057 struct fill_search_info_args { 2058 int request; 2059 unsigned int flags; 2060 Dl_serinfo *serinfo; 2061 Dl_serpath *serpath; 2062 char *strspace; 2063 }; 2064 2065 static void * 2066 fill_search_info(const char *dir, size_t dirlen, void *param) 2067 { 2068 struct fill_search_info_args *arg; 2069 2070 arg = param; 2071 2072 if (arg->request == RTLD_DI_SERINFOSIZE) { 2073 arg->serinfo->dls_cnt ++; 2074 arg->serinfo->dls_size += dirlen + 1; 2075 } else { 2076 struct dl_serpath *s_entry; 2077 2078 s_entry = arg->serpath; 2079 s_entry->dls_name = arg->strspace; 2080 s_entry->dls_flags = arg->flags; 2081 2082 strncpy(arg->strspace, dir, dirlen); 2083 arg->strspace[dirlen] = '\0'; 2084 2085 arg->strspace += dirlen + 1; 2086 arg->serpath++; 2087 } 2088 2089 return (NULL); 2090 } 2091 2092 static int 2093 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2094 { 2095 struct dl_serinfo _info; 2096 struct fill_search_info_args args; 2097 2098 args.request = RTLD_DI_SERINFOSIZE; 2099 args.serinfo = &_info; 2100 2101 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2102 _info.dls_cnt = 0; 2103 2104 path_enumerate(ld_library_path, fill_search_info, &args); 2105 path_enumerate(obj->rpath, fill_search_info, &args); 2106 path_enumerate(gethints(), fill_search_info, &args); 2107 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2108 2109 2110 if (request == RTLD_DI_SERINFOSIZE) { 2111 info->dls_size = _info.dls_size; 2112 info->dls_cnt = _info.dls_cnt; 2113 return (0); 2114 } 2115 2116 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2117 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2118 return (-1); 2119 } 2120 2121 args.request = RTLD_DI_SERINFO; 2122 args.serinfo = info; 2123 args.serpath = &info->dls_serpath[0]; 2124 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2125 2126 args.flags = LA_SER_LIBPATH; 2127 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2128 return (-1); 2129 2130 args.flags = LA_SER_RUNPATH; 2131 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2132 return (-1); 2133 2134 args.flags = LA_SER_CONFIG; 2135 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2136 return (-1); 2137 2138 args.flags = LA_SER_DEFAULT; 2139 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2140 return (-1); 2141 return (0); 2142 } 2143 2144 static int 2145 rtld_dirname(const char *path, char *bname) 2146 { 2147 const char *endp; 2148 2149 /* Empty or NULL string gets treated as "." */ 2150 if (path == NULL || *path == '\0') { 2151 bname[0] = '.'; 2152 bname[1] = '\0'; 2153 return (0); 2154 } 2155 2156 /* Strip trailing slashes */ 2157 endp = path + strlen(path) - 1; 2158 while (endp > path && *endp == '/') 2159 endp--; 2160 2161 /* Find the start of the dir */ 2162 while (endp > path && *endp != '/') 2163 endp--; 2164 2165 /* Either the dir is "/" or there are no slashes */ 2166 if (endp == path) { 2167 bname[0] = *endp == '/' ? '/' : '.'; 2168 bname[1] = '\0'; 2169 return (0); 2170 } else { 2171 do { 2172 endp--; 2173 } while (endp > path && *endp == '/'); 2174 } 2175 2176 if (endp - path + 2 > PATH_MAX) 2177 { 2178 _rtld_error("Filename is too long: %s", path); 2179 return(-1); 2180 } 2181 2182 strncpy(bname, path, endp - path + 1); 2183 bname[endp - path + 1] = '\0'; 2184 return (0); 2185 } 2186 2187 static void 2188 linkmap_add(Obj_Entry *obj) 2189 { 2190 struct link_map *l = &obj->linkmap; 2191 struct link_map *prev; 2192 2193 obj->linkmap.l_name = obj->path; 2194 obj->linkmap.l_addr = obj->mapbase; 2195 obj->linkmap.l_ld = obj->dynamic; 2196 #ifdef __mips__ 2197 /* GDB needs load offset on MIPS to use the symbols */ 2198 obj->linkmap.l_offs = obj->relocbase; 2199 #endif 2200 2201 if (r_debug.r_map == NULL) { 2202 r_debug.r_map = l; 2203 return; 2204 } 2205 2206 /* 2207 * Scan to the end of the list, but not past the entry for the 2208 * dynamic linker, which we want to keep at the very end. 2209 */ 2210 for (prev = r_debug.r_map; 2211 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2212 prev = prev->l_next) 2213 ; 2214 2215 /* Link in the new entry. */ 2216 l->l_prev = prev; 2217 l->l_next = prev->l_next; 2218 if (l->l_next != NULL) 2219 l->l_next->l_prev = l; 2220 prev->l_next = l; 2221 } 2222 2223 static void 2224 linkmap_delete(Obj_Entry *obj) 2225 { 2226 struct link_map *l = &obj->linkmap; 2227 2228 if (l->l_prev == NULL) { 2229 if ((r_debug.r_map = l->l_next) != NULL) 2230 l->l_next->l_prev = NULL; 2231 return; 2232 } 2233 2234 if ((l->l_prev->l_next = l->l_next) != NULL) 2235 l->l_next->l_prev = l->l_prev; 2236 } 2237 2238 /* 2239 * Function for the debugger to set a breakpoint on to gain control. 2240 * 2241 * The two parameters allow the debugger to easily find and determine 2242 * what the runtime loader is doing and to whom it is doing it. 2243 * 2244 * When the loadhook trap is hit (r_debug_state, set at program 2245 * initialization), the arguments can be found on the stack: 2246 * 2247 * +8 struct link_map *m 2248 * +4 struct r_debug *rd 2249 * +0 RetAddr 2250 */ 2251 void 2252 r_debug_state(struct r_debug* rd, struct link_map *m) 2253 { 2254 } 2255 2256 /* 2257 * Get address of the pointer variable in the main program. 2258 */ 2259 static const void ** 2260 get_program_var_addr(const char *name) 2261 { 2262 const Obj_Entry *obj; 2263 unsigned long hash; 2264 2265 hash = elf_hash(name); 2266 for (obj = obj_main; obj != NULL; obj = obj->next) { 2267 const Elf_Sym *def; 2268 2269 if ((def = symlook_obj(name, hash, obj, false)) != NULL) { 2270 const void **addr; 2271 2272 addr = (const void **)(obj->relocbase + def->st_value); 2273 return addr; 2274 } 2275 } 2276 return NULL; 2277 } 2278 2279 /* 2280 * Set a pointer variable in the main program to the given value. This 2281 * is used to set key variables such as "environ" before any of the 2282 * init functions are called. 2283 */ 2284 static void 2285 set_program_var(const char *name, const void *value) 2286 { 2287 const void **addr; 2288 2289 if ((addr = get_program_var_addr(name)) != NULL) { 2290 dbg("\"%s\": *%p <-- %p", name, addr, value); 2291 *addr = value; 2292 } 2293 } 2294 2295 /* 2296 * This is a special version of getenv which is far more efficient 2297 * at finding LD_ environment vars. 2298 */ 2299 static 2300 const char * 2301 _getenv_ld(const char *id) 2302 { 2303 const char *envp; 2304 int i, j; 2305 int idlen = strlen(id); 2306 2307 if (ld_index == LD_ARY_CACHE) 2308 return(getenv(id)); 2309 if (ld_index == 0) { 2310 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 2311 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 2312 ld_ary[j++] = envp; 2313 } 2314 if (j == 0) 2315 ld_ary[j++] = ""; 2316 ld_index = j; 2317 } 2318 for (i = ld_index - 1; i >= 0; --i) { 2319 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 2320 return(ld_ary[i] + idlen + 1); 2321 } 2322 return(NULL); 2323 } 2324 2325 /* 2326 * Given a symbol name in a referencing object, find the corresponding 2327 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2328 * no definition was found. Returns a pointer to the Obj_Entry of the 2329 * defining object via the reference parameter DEFOBJ_OUT. 2330 */ 2331 static const Elf_Sym * 2332 symlook_default(const char *name, unsigned long hash, 2333 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt) 2334 { 2335 DoneList donelist; 2336 const Elf_Sym *def; 2337 const Elf_Sym *symp; 2338 const Obj_Entry *obj; 2339 const Obj_Entry *defobj; 2340 const Objlist_Entry *elm; 2341 def = NULL; 2342 defobj = NULL; 2343 donelist_init(&donelist); 2344 2345 /* Look first in the referencing object if linked symbolically. */ 2346 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2347 symp = symlook_obj(name, hash, refobj, in_plt); 2348 if (symp != NULL) { 2349 def = symp; 2350 defobj = refobj; 2351 } 2352 } 2353 2354 /* Search all objects loaded at program start up. */ 2355 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2356 symp = symlook_list(name, hash, &list_main, &obj, in_plt, &donelist); 2357 if (symp != NULL && 2358 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2359 def = symp; 2360 defobj = obj; 2361 } 2362 } 2363 2364 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2365 STAILQ_FOREACH(elm, &list_global, link) { 2366 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2367 break; 2368 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt, 2369 &donelist); 2370 if (symp != NULL && 2371 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2372 def = symp; 2373 defobj = obj; 2374 } 2375 } 2376 2377 /* Search all dlopened DAGs containing the referencing object. */ 2378 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2379 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2380 break; 2381 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt, 2382 &donelist); 2383 if (symp != NULL && 2384 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2385 def = symp; 2386 defobj = obj; 2387 } 2388 } 2389 2390 /* 2391 * Search the dynamic linker itself, and possibly resolve the 2392 * symbol from there. This is how the application links to 2393 * dynamic linker services such as dlopen. Only the values listed 2394 * in the "exports" array can be resolved from the dynamic linker. 2395 */ 2396 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2397 symp = symlook_obj(name, hash, &obj_rtld, in_plt); 2398 if (symp != NULL && is_exported(symp)) { 2399 def = symp; 2400 defobj = &obj_rtld; 2401 } 2402 } 2403 2404 if (def != NULL) 2405 *defobj_out = defobj; 2406 return def; 2407 } 2408 2409 static const Elf_Sym * 2410 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2411 const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp) 2412 { 2413 const Elf_Sym *symp; 2414 const Elf_Sym *def; 2415 const Obj_Entry *defobj; 2416 const Objlist_Entry *elm; 2417 2418 def = NULL; 2419 defobj = NULL; 2420 STAILQ_FOREACH(elm, objlist, link) { 2421 if (donelist_check(dlp, elm->obj)) 2422 continue; 2423 if ((symp = symlook_obj(name, hash, elm->obj, in_plt)) != NULL) { 2424 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2425 def = symp; 2426 defobj = elm->obj; 2427 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2428 break; 2429 } 2430 } 2431 } 2432 if (def != NULL) 2433 *defobj_out = defobj; 2434 return def; 2435 } 2436 2437 /* 2438 * Search the symbol table of a shared object and all objects needed 2439 * by it for a symbol of the given name. Search order is 2440 * breadth-first. Returns a pointer to the symbol, or NULL if no 2441 * definition was found. 2442 */ 2443 static const Elf_Sym * 2444 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2445 const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp) 2446 { 2447 const Elf_Sym *def, *def_w; 2448 const Needed_Entry *n; 2449 const Obj_Entry *obj, *defobj, *defobj1; 2450 2451 def = def_w = NULL; 2452 defobj = NULL; 2453 for (n = needed; n != NULL; n = n->next) { 2454 if ((obj = n->obj) == NULL || 2455 donelist_check(dlp, obj) || 2456 (def = symlook_obj(name, hash, obj, in_plt)) == NULL) 2457 continue; 2458 defobj = obj; 2459 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2460 *defobj_out = defobj; 2461 return (def); 2462 } 2463 } 2464 /* 2465 * There we come when either symbol definition is not found in 2466 * directly needed objects, or found symbol is weak. 2467 */ 2468 for (n = needed; n != NULL; n = n->next) { 2469 if ((obj = n->obj) == NULL) 2470 continue; 2471 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2472 in_plt, dlp); 2473 if (def_w == NULL) 2474 continue; 2475 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2476 def = def_w; 2477 defobj = defobj1; 2478 } 2479 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2480 break; 2481 } 2482 if (def != NULL) 2483 *defobj_out = defobj; 2484 return def; 2485 } 2486 2487 /* 2488 * Search the symbol table of a single shared object for a symbol of 2489 * the given name. Returns a pointer to the symbol, or NULL if no 2490 * definition was found. 2491 * 2492 * The symbol's hash value is passed in for efficiency reasons; that 2493 * eliminates many recomputations of the hash value. 2494 */ 2495 const Elf_Sym * 2496 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2497 bool in_plt) 2498 { 2499 if (obj->buckets != NULL) { 2500 unsigned long symnum = obj->buckets[hash % obj->nbuckets]; 2501 2502 while (symnum != STN_UNDEF) { 2503 const Elf_Sym *symp; 2504 const char *strp; 2505 2506 if (symnum >= obj->nchains) 2507 return NULL; /* Bad object */ 2508 symp = obj->symtab + symnum; 2509 strp = obj->strtab + symp->st_name; 2510 2511 if (name[0] == strp[0] && strcmp(name, strp) == 0) 2512 return symp->st_shndx != SHN_UNDEF || 2513 (!in_plt && symp->st_value != 0 && 2514 ELF_ST_TYPE(symp->st_info) == STT_FUNC) ? symp : NULL; 2515 2516 symnum = obj->chains[symnum]; 2517 } 2518 } 2519 return NULL; 2520 } 2521 2522 static void 2523 trace_loaded_objects(Obj_Entry *obj) 2524 { 2525 const char *fmt1, *fmt2, *fmt, *main_local; 2526 int c; 2527 2528 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2529 main_local = ""; 2530 2531 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2532 fmt1 = "\t%o => %p (%x)\n"; 2533 2534 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2535 fmt2 = "\t%o (%x)\n"; 2536 2537 for (; obj; obj = obj->next) { 2538 Needed_Entry *needed; 2539 char *name, *path; 2540 bool is_lib; 2541 2542 for (needed = obj->needed; needed; needed = needed->next) { 2543 if (needed->obj != NULL) { 2544 if (needed->obj->traced) 2545 continue; 2546 needed->obj->traced = true; 2547 path = needed->obj->path; 2548 } else 2549 path = "not found"; 2550 2551 name = (char *)obj->strtab + needed->name; 2552 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2553 2554 fmt = is_lib ? fmt1 : fmt2; 2555 while ((c = *fmt++) != '\0') { 2556 switch (c) { 2557 default: 2558 putchar(c); 2559 continue; 2560 case '\\': 2561 switch (c = *fmt) { 2562 case '\0': 2563 continue; 2564 case 'n': 2565 putchar('\n'); 2566 break; 2567 case 't': 2568 putchar('\t'); 2569 break; 2570 } 2571 break; 2572 case '%': 2573 switch (c = *fmt) { 2574 case '\0': 2575 continue; 2576 case '%': 2577 default: 2578 putchar(c); 2579 break; 2580 case 'A': 2581 printf("%s", main_local); 2582 break; 2583 case 'a': 2584 printf("%s", obj_main->path); 2585 break; 2586 case 'o': 2587 printf("%s", name); 2588 break; 2589 #if 0 2590 case 'm': 2591 printf("%d", sodp->sod_major); 2592 break; 2593 case 'n': 2594 printf("%d", sodp->sod_minor); 2595 break; 2596 #endif 2597 case 'p': 2598 printf("%s", path); 2599 break; 2600 case 'x': 2601 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2602 break; 2603 } 2604 break; 2605 } 2606 ++fmt; 2607 } 2608 } 2609 } 2610 } 2611 2612 /* 2613 * Unload a dlopened object and its dependencies from memory and from 2614 * our data structures. It is assumed that the DAG rooted in the 2615 * object has already been unreferenced, and that the object has a 2616 * reference count of 0. 2617 */ 2618 static void 2619 unload_object(Obj_Entry *root) 2620 { 2621 Obj_Entry *obj; 2622 Obj_Entry **linkp; 2623 2624 assert(root->refcount == 0); 2625 2626 /* 2627 * Pass over the DAG removing unreferenced objects from 2628 * appropriate lists. 2629 */ 2630 unlink_object(root); 2631 2632 /* Unmap all objects that are no longer referenced. */ 2633 linkp = &obj_list->next; 2634 while ((obj = *linkp) != NULL) { 2635 if (obj->refcount == 0) { 2636 dbg("unloading \"%s\"", obj->path); 2637 munmap(obj->mapbase, obj->mapsize); 2638 linkmap_delete(obj); 2639 *linkp = obj->next; 2640 obj_count--; 2641 obj_free(obj); 2642 } else 2643 linkp = &obj->next; 2644 } 2645 obj_tail = linkp; 2646 } 2647 2648 static void 2649 unlink_object(Obj_Entry *root) 2650 { 2651 const Needed_Entry *needed; 2652 Objlist_Entry *elm; 2653 2654 if (root->refcount == 0) { 2655 /* Remove the object from the RTLD_GLOBAL list. */ 2656 objlist_remove(&list_global, root); 2657 2658 /* Remove the object from all objects' DAG lists. */ 2659 STAILQ_FOREACH(elm, &root->dagmembers , link) 2660 objlist_remove(&elm->obj->dldags, root); 2661 } 2662 2663 for (needed = root->needed; needed != NULL; needed = needed->next) 2664 if (needed->obj != NULL) 2665 unlink_object(needed->obj); 2666 } 2667 2668 static void 2669 unref_dag(Obj_Entry *root) 2670 { 2671 const Needed_Entry *needed; 2672 2673 if (root->refcount == 0) 2674 return; 2675 root->refcount--; 2676 if (root->refcount == 0) 2677 for (needed = root->needed; needed != NULL; needed = needed->next) 2678 if (needed->obj != NULL) 2679 unref_dag(needed->obj); 2680 } 2681 2682 /* 2683 * Common code for MD __tls_get_addr(). 2684 */ 2685 void * 2686 tls_get_addr_common(void **dtvp, int index, size_t offset) 2687 { 2688 Elf_Addr* dtv = *dtvp; 2689 2690 /* Check dtv generation in case new modules have arrived */ 2691 if (dtv[0] != tls_dtv_generation) { 2692 Elf_Addr* newdtv; 2693 int to_copy; 2694 2695 wlock_acquire(); 2696 2697 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 2698 to_copy = dtv[1]; 2699 if (to_copy > tls_max_index) 2700 to_copy = tls_max_index; 2701 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 2702 newdtv[0] = tls_dtv_generation; 2703 newdtv[1] = tls_max_index; 2704 free(dtv); 2705 *dtvp = newdtv; 2706 2707 wlock_release(); 2708 } 2709 2710 /* Dynamically allocate module TLS if necessary */ 2711 if (!dtv[index + 1]) { 2712 /* XXX 2713 * here we should avoid to be re-entered by signal handler 2714 * code, I assume wlock_acquire will masked all signals, 2715 * otherwise there is race and dead lock thread itself. 2716 */ 2717 wlock_acquire(); 2718 if (!dtv[index + 1]) 2719 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 2720 wlock_release(); 2721 } 2722 2723 return (void*) (dtv[index + 1] + offset); 2724 } 2725 2726 #if defined(RTLD_STATIC_TLS_VARIANT_II) 2727 2728 /* 2729 * Allocate the static TLS area. Return a pointer to the TCB. The 2730 * static area is based on negative offsets relative to the tcb. 2731 * 2732 * The TCB contains an errno pointer for the system call layer, but because 2733 * we are the RTLD we really have no idea how the caller was compiled so 2734 * the information has to be passed in. errno can either be: 2735 * 2736 * type 0 errno is a simple non-TLS global pointer. 2737 * (special case for e.g. libc_rtld) 2738 * type 1 errno accessed by GOT entry (dynamically linked programs) 2739 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 2740 */ 2741 struct tls_tcb * 2742 allocate_tls(Obj_Entry *objs) 2743 { 2744 Obj_Entry *obj; 2745 size_t data_size; 2746 size_t dtv_size; 2747 struct tls_tcb *tcb; 2748 Elf_Addr *dtv; 2749 Elf_Addr addr; 2750 2751 /* 2752 * Allocate the new TCB. static TLS storage is placed just before the 2753 * TCB to support the %gs:OFFSET (negative offset) model. 2754 */ 2755 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 2756 ~RTLD_STATIC_TLS_ALIGN_MASK; 2757 tcb = malloc(data_size + sizeof(*tcb)); 2758 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 2759 2760 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 2761 dtv = malloc(dtv_size); 2762 bzero(dtv, dtv_size); 2763 2764 #ifdef RTLD_TCB_HAS_SELF_POINTER 2765 tcb->tcb_self = tcb; 2766 #endif 2767 tcb->tcb_dtv = dtv; 2768 tcb->tcb_pthread = NULL; 2769 2770 dtv[0] = tls_dtv_generation; 2771 dtv[1] = tls_max_index; 2772 2773 for (obj = objs; obj; obj = obj->next) { 2774 if (obj->tlsoffset) { 2775 addr = (Elf_Addr)tcb - obj->tlsoffset; 2776 memset((void *)(addr + obj->tlsinitsize), 2777 0, obj->tlssize - obj->tlsinitsize); 2778 if (obj->tlsinit) 2779 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 2780 dtv[obj->tlsindex + 1] = addr; 2781 } 2782 } 2783 return(tcb); 2784 } 2785 2786 void 2787 free_tls(struct tls_tcb *tcb) 2788 { 2789 Elf_Addr *dtv; 2790 int dtv_size, i; 2791 Elf_Addr tls_start, tls_end; 2792 size_t data_size; 2793 2794 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 2795 ~RTLD_STATIC_TLS_ALIGN_MASK; 2796 dtv = tcb->tcb_dtv; 2797 dtv_size = dtv[1]; 2798 tls_end = (Elf_Addr)tcb; 2799 tls_start = (Elf_Addr)tcb - data_size; 2800 for (i = 0; i < dtv_size; i++) { 2801 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 2802 free((void *)dtv[i+2]); 2803 } 2804 } 2805 free((void *)tls_start); 2806 } 2807 2808 #else 2809 #error "Unsupported TLS layout" 2810 #endif 2811 2812 /* 2813 * Allocate TLS block for module with given index. 2814 */ 2815 void * 2816 allocate_module_tls(int index) 2817 { 2818 Obj_Entry* obj; 2819 char* p; 2820 2821 for (obj = obj_list; obj; obj = obj->next) { 2822 if (obj->tlsindex == index) 2823 break; 2824 } 2825 if (!obj) { 2826 _rtld_error("Can't find module with TLS index %d", index); 2827 die(); 2828 } 2829 2830 p = malloc(obj->tlssize); 2831 memcpy(p, obj->tlsinit, obj->tlsinitsize); 2832 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 2833 2834 return p; 2835 } 2836 2837 bool 2838 allocate_tls_offset(Obj_Entry *obj) 2839 { 2840 size_t off; 2841 2842 if (obj->tls_done) 2843 return true; 2844 2845 if (obj->tlssize == 0) { 2846 obj->tls_done = true; 2847 return true; 2848 } 2849 2850 if (obj->tlsindex == 1) 2851 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 2852 else 2853 off = calculate_tls_offset(tls_last_offset, tls_last_size, 2854 obj->tlssize, obj->tlsalign); 2855 2856 /* 2857 * If we have already fixed the size of the static TLS block, we 2858 * must stay within that size. When allocating the static TLS, we 2859 * leave a small amount of space spare to be used for dynamically 2860 * loading modules which use static TLS. 2861 */ 2862 if (tls_static_space) { 2863 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 2864 return false; 2865 } 2866 2867 tls_last_offset = obj->tlsoffset = off; 2868 tls_last_size = obj->tlssize; 2869 obj->tls_done = true; 2870 2871 return true; 2872 } 2873 2874 void 2875 free_tls_offset(Obj_Entry *obj) 2876 { 2877 #ifdef RTLD_STATIC_TLS_VARIANT_II 2878 /* 2879 * If we were the last thing to allocate out of the static TLS 2880 * block, we give our space back to the 'allocator'. This is a 2881 * simplistic workaround to allow libGL.so.1 to be loaded and 2882 * unloaded multiple times. We only handle the Variant II 2883 * mechanism for now - this really needs a proper allocator. 2884 */ 2885 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 2886 == calculate_tls_end(tls_last_offset, tls_last_size)) { 2887 tls_last_offset -= obj->tlssize; 2888 tls_last_size = 0; 2889 } 2890 #endif 2891 } 2892 2893 struct tls_tcb * 2894 _rtld_allocate_tls(void) 2895 { 2896 struct tls_tcb *new_tcb; 2897 2898 wlock_acquire(); 2899 new_tcb = allocate_tls(obj_list); 2900 wlock_release(); 2901 2902 return (new_tcb); 2903 } 2904 2905 void 2906 _rtld_free_tls(struct tls_tcb *tcb) 2907 { 2908 wlock_acquire(); 2909 free_tls(tcb); 2910 wlock_release(); 2911 } 2912 2913