1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 44 #include <dlfcn.h> 45 #include <err.h> 46 #include <errno.h> 47 #include <fcntl.h> 48 #include <stdarg.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 #include "debug.h" 55 #include "rtld.h" 56 #include "libmap.h" 57 #include "rtld_tls.h" 58 59 #ifndef COMPAT_32BIT 60 #define PATH_RTLD "/libexec/ld-elf.so.1" 61 #else 62 #define PATH_RTLD "/libexec/ld-elf32.so.1" 63 #endif 64 65 /* Types. */ 66 typedef void (*func_ptr_type)(); 67 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 68 69 /* 70 * This structure provides a reentrant way to keep a list of objects and 71 * check which ones have already been processed in some way. 72 */ 73 typedef struct Struct_DoneList { 74 const Obj_Entry **objs; /* Array of object pointers */ 75 unsigned int num_alloc; /* Allocated size of the array */ 76 unsigned int num_used; /* Number of array slots used */ 77 } DoneList; 78 79 /* 80 * Function declarations. 81 */ 82 static const char *basename(const char *); 83 static void die(void) __dead2; 84 static void digest_dynamic(Obj_Entry *, int); 85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 86 static Obj_Entry *dlcheck(void *); 87 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *); 88 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 89 static bool donelist_check(DoneList *, const Obj_Entry *); 90 static void errmsg_restore(char *); 91 static char *errmsg_save(void); 92 static void *fill_search_info(const char *, size_t, void *); 93 static char *find_library(const char *, const Obj_Entry *); 94 static const char *gethints(void); 95 static void init_dag(Obj_Entry *); 96 static void init_dag1(Obj_Entry *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(const char *, const Obj_Entry *); 107 static Obj_Entry *obj_from_addr(const void *); 108 static void objlist_call_fini(Objlist *); 109 static void objlist_call_init(Objlist *); 110 static void objlist_clear(Objlist *); 111 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 112 static void objlist_init(Objlist *); 113 static void objlist_push_head(Objlist *, Obj_Entry *); 114 static void objlist_push_tail(Objlist *, Obj_Entry *); 115 static void objlist_remove(Objlist *, Obj_Entry *); 116 static void objlist_remove_unref(Objlist *); 117 static void *path_enumerate(const char *, path_enum_proc, void *); 118 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 119 static int rtld_dirname(const char *, char *); 120 static void rtld_exit(void); 121 static char *search_library_path(const char *, const char *); 122 static const void **get_program_var_addr(const char *); 123 static void set_program_var(const char *, const void *); 124 static const Elf_Sym *symlook_default(const char *, unsigned long, 125 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 126 static const Elf_Sym *symlook_list(const char *, unsigned long, Objlist *, 127 const Obj_Entry **, const Ver_Entry *, int flags, DoneList *); 128 static void trace_loaded_objects(Obj_Entry *obj); 129 static void unlink_object(Obj_Entry *); 130 static void unload_object(Obj_Entry *); 131 static void unref_dag(Obj_Entry *); 132 static void ref_dag(Obj_Entry *); 133 static int rtld_verify_versions(const Objlist *); 134 static int rtld_verify_object_versions(Obj_Entry *); 135 static void object_add_name(Obj_Entry *, const char *); 136 static int object_match_name(const Obj_Entry *, const char *); 137 138 void r_debug_state(struct r_debug*, struct link_map*); 139 140 /* 141 * Data declarations. 142 */ 143 static char *error_message; /* Message for dlerror(), or NULL */ 144 struct r_debug r_debug; /* for GDB; */ 145 static bool libmap_disable; /* Disable libmap */ 146 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 147 static bool trust; /* False for setuid and setgid programs */ 148 static bool dangerous_ld_env; /* True if environment variables have been 149 used to affect the libraries loaded */ 150 static char *ld_bind_now; /* Environment variable for immediate binding */ 151 static char *ld_debug; /* Environment variable for debugging */ 152 static char *ld_library_path; /* Environment variable for search path */ 153 static char *ld_preload; /* Environment variable for libraries to 154 load first */ 155 static char *ld_tracing; /* Called from ldd to print libs */ 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 *obj_main; /* The main program shared object */ 159 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 160 static unsigned int obj_count; /* Number of objects in obj_list */ 161 162 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 163 STAILQ_HEAD_INITIALIZER(list_global); 164 static Objlist list_main = /* Objects loaded at program startup */ 165 STAILQ_HEAD_INITIALIZER(list_main); 166 static Objlist list_fini = /* Objects needing fini() calls */ 167 STAILQ_HEAD_INITIALIZER(list_fini); 168 169 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 170 171 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 172 173 extern Elf_Dyn _DYNAMIC; 174 #pragma weak _DYNAMIC 175 #ifndef RTLD_IS_DYNAMIC 176 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 177 #endif 178 179 /* 180 * These are the functions the dynamic linker exports to application 181 * programs. They are the only symbols the dynamic linker is willing 182 * to export from itself. 183 */ 184 static func_ptr_type exports[] = { 185 (func_ptr_type) &_rtld_error, 186 (func_ptr_type) &dlclose, 187 (func_ptr_type) &dlerror, 188 (func_ptr_type) &dlopen, 189 (func_ptr_type) &dlsym, 190 (func_ptr_type) &dlvsym, 191 (func_ptr_type) &dladdr, 192 (func_ptr_type) &dllockinit, 193 (func_ptr_type) &dlinfo, 194 (func_ptr_type) &_rtld_thread_init, 195 #ifdef __i386__ 196 (func_ptr_type) &___tls_get_addr, 197 #endif 198 (func_ptr_type) &__tls_get_addr, 199 (func_ptr_type) &_rtld_allocate_tls, 200 (func_ptr_type) &_rtld_free_tls, 201 NULL 202 }; 203 204 /* 205 * Global declarations normally provided by crt1. The dynamic linker is 206 * not built with crt1, so we have to provide them ourselves. 207 */ 208 char *__progname; 209 char **environ; 210 211 /* 212 * Globals to control TLS allocation. 213 */ 214 size_t tls_last_offset; /* Static TLS offset of last module */ 215 size_t tls_last_size; /* Static TLS size of last module */ 216 size_t tls_static_space; /* Static TLS space allocated */ 217 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 218 int tls_max_index = 1; /* Largest module index allocated */ 219 220 /* 221 * Fill in a DoneList with an allocation large enough to hold all of 222 * the currently-loaded objects. Keep this as a macro since it calls 223 * alloca and we want that to occur within the scope of the caller. 224 */ 225 #define donelist_init(dlp) \ 226 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 227 assert((dlp)->objs != NULL), \ 228 (dlp)->num_alloc = obj_count, \ 229 (dlp)->num_used = 0) 230 231 /* 232 * Main entry point for dynamic linking. The first argument is the 233 * stack pointer. The stack is expected to be laid out as described 234 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 235 * Specifically, the stack pointer points to a word containing 236 * ARGC. Following that in the stack is a null-terminated sequence 237 * of pointers to argument strings. Then comes a null-terminated 238 * sequence of pointers to environment strings. Finally, there is a 239 * sequence of "auxiliary vector" entries. 240 * 241 * The second argument points to a place to store the dynamic linker's 242 * exit procedure pointer and the third to a place to store the main 243 * program's object. 244 * 245 * The return value is the main program's entry point. 246 */ 247 func_ptr_type 248 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 249 { 250 Elf_Auxinfo *aux_info[AT_COUNT]; 251 int i; 252 int argc; 253 char **argv; 254 char **env; 255 Elf_Auxinfo *aux; 256 Elf_Auxinfo *auxp; 257 const char *argv0; 258 Objlist_Entry *entry; 259 Obj_Entry *obj; 260 Obj_Entry **preload_tail; 261 Objlist initlist; 262 int lockstate; 263 264 /* 265 * On entry, the dynamic linker itself has not been relocated yet. 266 * Be very careful not to reference any global data until after 267 * init_rtld has returned. It is OK to reference file-scope statics 268 * and string constants, and to call static and global functions. 269 */ 270 271 /* Find the auxiliary vector on the stack. */ 272 argc = *sp++; 273 argv = (char **) sp; 274 sp += argc + 1; /* Skip over arguments and NULL terminator */ 275 env = (char **) sp; 276 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 277 ; 278 aux = (Elf_Auxinfo *) sp; 279 280 /* Digest the auxiliary vector. */ 281 for (i = 0; i < AT_COUNT; i++) 282 aux_info[i] = NULL; 283 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 284 if (auxp->a_type < AT_COUNT) 285 aux_info[auxp->a_type] = auxp; 286 } 287 288 /* Initialize and relocate ourselves. */ 289 assert(aux_info[AT_BASE] != NULL); 290 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 291 292 __progname = obj_rtld.path; 293 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 294 environ = env; 295 296 trust = !issetugid(); 297 298 ld_bind_now = getenv(LD_ "BIND_NOW"); 299 if (trust) { 300 ld_debug = getenv(LD_ "DEBUG"); 301 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 302 libmap_override = getenv(LD_ "LIBMAP"); 303 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 304 ld_preload = getenv(LD_ "PRELOAD"); 305 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 306 (ld_library_path != NULL) || (ld_preload != NULL); 307 } else 308 dangerous_ld_env = 0; 309 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 310 311 if (ld_debug != NULL && *ld_debug != '\0') 312 debug = 1; 313 dbg("%s is initialized, base address = %p", __progname, 314 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 315 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 316 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 317 318 /* 319 * Load the main program, or process its program header if it is 320 * already loaded. 321 */ 322 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 323 int fd = aux_info[AT_EXECFD]->a_un.a_val; 324 dbg("loading main program"); 325 obj_main = map_object(fd, argv0, NULL); 326 close(fd); 327 if (obj_main == NULL) 328 die(); 329 } else { /* Main program already loaded. */ 330 const Elf_Phdr *phdr; 331 int phnum; 332 caddr_t entry; 333 334 dbg("processing main program's program header"); 335 assert(aux_info[AT_PHDR] != NULL); 336 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 337 assert(aux_info[AT_PHNUM] != NULL); 338 phnum = aux_info[AT_PHNUM]->a_un.a_val; 339 assert(aux_info[AT_PHENT] != NULL); 340 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 341 assert(aux_info[AT_ENTRY] != NULL); 342 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 343 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 344 die(); 345 } 346 347 obj_main->path = xstrdup(argv0); 348 obj_main->mainprog = true; 349 350 /* 351 * Get the actual dynamic linker pathname from the executable if 352 * possible. (It should always be possible.) That ensures that 353 * gdb will find the right dynamic linker even if a non-standard 354 * one is being used. 355 */ 356 if (obj_main->interp != NULL && 357 strcmp(obj_main->interp, obj_rtld.path) != 0) { 358 free(obj_rtld.path); 359 obj_rtld.path = xstrdup(obj_main->interp); 360 __progname = obj_rtld.path; 361 } 362 363 digest_dynamic(obj_main, 0); 364 365 linkmap_add(obj_main); 366 linkmap_add(&obj_rtld); 367 368 /* Link the main program into the list of objects. */ 369 *obj_tail = obj_main; 370 obj_tail = &obj_main->next; 371 obj_count++; 372 /* Make sure we don't call the main program's init and fini functions. */ 373 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 374 375 /* Initialize a fake symbol for resolving undefined weak references. */ 376 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 377 sym_zero.st_shndx = SHN_UNDEF; 378 379 if (!libmap_disable) 380 libmap_disable = (bool)lm_init(libmap_override); 381 382 dbg("loading LD_PRELOAD libraries"); 383 if (load_preload_objects() == -1) 384 die(); 385 preload_tail = obj_tail; 386 387 dbg("loading needed objects"); 388 if (load_needed_objects(obj_main) == -1) 389 die(); 390 391 /* Make a list of all objects loaded at startup. */ 392 for (obj = obj_list; obj != NULL; obj = obj->next) { 393 objlist_push_tail(&list_main, obj); 394 obj->refcount++; 395 } 396 397 dbg("checking for required versions"); 398 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 399 die(); 400 401 if (ld_tracing) { /* We're done */ 402 trace_loaded_objects(obj_main); 403 exit(0); 404 } 405 406 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 407 dump_relocations(obj_main); 408 exit (0); 409 } 410 411 /* setup TLS for main thread */ 412 dbg("initializing initial thread local storage"); 413 STAILQ_FOREACH(entry, &list_main, link) { 414 /* 415 * Allocate all the initial objects out of the static TLS 416 * block even if they didn't ask for it. 417 */ 418 allocate_tls_offset(entry->obj); 419 } 420 allocate_initial_tls(obj_list); 421 422 if (relocate_objects(obj_main, 423 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 424 die(); 425 426 dbg("doing copy relocations"); 427 if (do_copy_relocations(obj_main) == -1) 428 die(); 429 430 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 431 dump_relocations(obj_main); 432 exit (0); 433 } 434 435 dbg("initializing key program variables"); 436 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 437 set_program_var("environ", env); 438 439 dbg("initializing thread locks"); 440 lockdflt_init(); 441 442 /* Make a list of init functions to call. */ 443 objlist_init(&initlist); 444 initlist_add_objects(obj_list, preload_tail, &initlist); 445 446 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 447 448 objlist_call_init(&initlist); 449 lockstate = wlock_acquire(rtld_bind_lock); 450 objlist_clear(&initlist); 451 wlock_release(rtld_bind_lock, lockstate); 452 453 dbg("transferring control to program entry point = %p", obj_main->entry); 454 455 /* Return the exit procedure and the program entry point. */ 456 *exit_proc = rtld_exit; 457 *objp = obj_main; 458 return (func_ptr_type) obj_main->entry; 459 } 460 461 Elf_Addr 462 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 463 { 464 const Elf_Rel *rel; 465 const Elf_Sym *def; 466 const Obj_Entry *defobj; 467 Elf_Addr *where; 468 Elf_Addr target; 469 int lockstate; 470 471 lockstate = rlock_acquire(rtld_bind_lock); 472 if (obj->pltrel) 473 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 474 else 475 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 476 477 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 478 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 479 if (def == NULL) 480 die(); 481 482 target = (Elf_Addr)(defobj->relocbase + def->st_value); 483 484 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 485 defobj->strtab + def->st_name, basename(obj->path), 486 (void *)target, basename(defobj->path)); 487 488 /* 489 * Write the new contents for the jmpslot. Note that depending on 490 * architecture, the value which we need to return back to the 491 * lazy binding trampoline may or may not be the target 492 * address. The value returned from reloc_jmpslot() is the value 493 * that the trampoline needs. 494 */ 495 target = reloc_jmpslot(where, target, defobj, obj, rel); 496 rlock_release(rtld_bind_lock, lockstate); 497 return target; 498 } 499 500 /* 501 * Error reporting function. Use it like printf. If formats the message 502 * into a buffer, and sets things up so that the next call to dlerror() 503 * will return the message. 504 */ 505 void 506 _rtld_error(const char *fmt, ...) 507 { 508 static char buf[512]; 509 va_list ap; 510 511 va_start(ap, fmt); 512 vsnprintf(buf, sizeof buf, fmt, ap); 513 error_message = buf; 514 va_end(ap); 515 } 516 517 /* 518 * Return a dynamically-allocated copy of the current error message, if any. 519 */ 520 static char * 521 errmsg_save(void) 522 { 523 return error_message == NULL ? NULL : xstrdup(error_message); 524 } 525 526 /* 527 * Restore the current error message from a copy which was previously saved 528 * by errmsg_save(). The copy is freed. 529 */ 530 static void 531 errmsg_restore(char *saved_msg) 532 { 533 if (saved_msg == NULL) 534 error_message = NULL; 535 else { 536 _rtld_error("%s", saved_msg); 537 free(saved_msg); 538 } 539 } 540 541 static const char * 542 basename(const char *name) 543 { 544 const char *p = strrchr(name, '/'); 545 return p != NULL ? p + 1 : name; 546 } 547 548 static void 549 die(void) 550 { 551 const char *msg = dlerror(); 552 553 if (msg == NULL) 554 msg = "Fatal error"; 555 errx(1, "%s", msg); 556 } 557 558 /* 559 * Process a shared object's DYNAMIC section, and save the important 560 * information in its Obj_Entry structure. 561 */ 562 static void 563 digest_dynamic(Obj_Entry *obj, int early) 564 { 565 const Elf_Dyn *dynp; 566 Needed_Entry **needed_tail = &obj->needed; 567 const Elf_Dyn *dyn_rpath = NULL; 568 const Elf_Dyn *dyn_soname = NULL; 569 int plttype = DT_REL; 570 571 obj->bind_now = false; 572 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 573 switch (dynp->d_tag) { 574 575 case DT_REL: 576 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 577 break; 578 579 case DT_RELSZ: 580 obj->relsize = dynp->d_un.d_val; 581 break; 582 583 case DT_RELENT: 584 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 585 break; 586 587 case DT_JMPREL: 588 obj->pltrel = (const Elf_Rel *) 589 (obj->relocbase + dynp->d_un.d_ptr); 590 break; 591 592 case DT_PLTRELSZ: 593 obj->pltrelsize = dynp->d_un.d_val; 594 break; 595 596 case DT_RELA: 597 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 598 break; 599 600 case DT_RELASZ: 601 obj->relasize = dynp->d_un.d_val; 602 break; 603 604 case DT_RELAENT: 605 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 606 break; 607 608 case DT_PLTREL: 609 plttype = dynp->d_un.d_val; 610 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 611 break; 612 613 case DT_SYMTAB: 614 obj->symtab = (const Elf_Sym *) 615 (obj->relocbase + dynp->d_un.d_ptr); 616 break; 617 618 case DT_SYMENT: 619 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 620 break; 621 622 case DT_STRTAB: 623 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 624 break; 625 626 case DT_STRSZ: 627 obj->strsize = dynp->d_un.d_val; 628 break; 629 630 case DT_VERNEED: 631 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 632 dynp->d_un.d_val); 633 break; 634 635 case DT_VERNEEDNUM: 636 obj->verneednum = dynp->d_un.d_val; 637 break; 638 639 case DT_VERDEF: 640 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 641 dynp->d_un.d_val); 642 break; 643 644 case DT_VERDEFNUM: 645 obj->verdefnum = dynp->d_un.d_val; 646 break; 647 648 case DT_VERSYM: 649 obj->versyms = (const Elf_Versym *)(obj->relocbase + 650 dynp->d_un.d_val); 651 break; 652 653 case DT_HASH: 654 { 655 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 656 (obj->relocbase + dynp->d_un.d_ptr); 657 obj->nbuckets = hashtab[0]; 658 obj->nchains = hashtab[1]; 659 obj->buckets = hashtab + 2; 660 obj->chains = obj->buckets + obj->nbuckets; 661 } 662 break; 663 664 case DT_NEEDED: 665 if (!obj->rtld) { 666 Needed_Entry *nep = NEW(Needed_Entry); 667 nep->name = dynp->d_un.d_val; 668 nep->obj = NULL; 669 nep->next = NULL; 670 671 *needed_tail = nep; 672 needed_tail = &nep->next; 673 } 674 break; 675 676 case DT_PLTGOT: 677 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 678 break; 679 680 case DT_TEXTREL: 681 obj->textrel = true; 682 break; 683 684 case DT_SYMBOLIC: 685 obj->symbolic = true; 686 break; 687 688 case DT_RPATH: 689 case DT_RUNPATH: /* XXX: process separately */ 690 /* 691 * We have to wait until later to process this, because we 692 * might not have gotten the address of the string table yet. 693 */ 694 dyn_rpath = dynp; 695 break; 696 697 case DT_SONAME: 698 dyn_soname = dynp; 699 break; 700 701 case DT_INIT: 702 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 703 break; 704 705 case DT_FINI: 706 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 707 break; 708 709 case DT_DEBUG: 710 /* XXX - not implemented yet */ 711 if (!early) 712 dbg("Filling in DT_DEBUG entry"); 713 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 714 break; 715 716 case DT_FLAGS: 717 if (dynp->d_un.d_val & DF_ORIGIN) { 718 obj->origin_path = xmalloc(PATH_MAX); 719 if (rtld_dirname(obj->path, obj->origin_path) == -1) 720 die(); 721 } 722 if (dynp->d_un.d_val & DF_SYMBOLIC) 723 obj->symbolic = true; 724 if (dynp->d_un.d_val & DF_TEXTREL) 725 obj->textrel = true; 726 if (dynp->d_un.d_val & DF_BIND_NOW) 727 obj->bind_now = true; 728 if (dynp->d_un.d_val & DF_STATIC_TLS) 729 ; 730 break; 731 732 default: 733 if (!early) { 734 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 735 (long)dynp->d_tag); 736 } 737 break; 738 } 739 } 740 741 obj->traced = false; 742 743 if (plttype == DT_RELA) { 744 obj->pltrela = (const Elf_Rela *) obj->pltrel; 745 obj->pltrel = NULL; 746 obj->pltrelasize = obj->pltrelsize; 747 obj->pltrelsize = 0; 748 } 749 750 if (dyn_rpath != NULL) 751 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val; 752 753 if (dyn_soname != NULL) 754 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 755 } 756 757 /* 758 * Process a shared object's program header. This is used only for the 759 * main program, when the kernel has already loaded the main program 760 * into memory before calling the dynamic linker. It creates and 761 * returns an Obj_Entry structure. 762 */ 763 static Obj_Entry * 764 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 765 { 766 Obj_Entry *obj; 767 const Elf_Phdr *phlimit = phdr + phnum; 768 const Elf_Phdr *ph; 769 int nsegs = 0; 770 771 obj = obj_new(); 772 for (ph = phdr; ph < phlimit; ph++) { 773 switch (ph->p_type) { 774 775 case PT_PHDR: 776 if ((const Elf_Phdr *)ph->p_vaddr != phdr) { 777 _rtld_error("%s: invalid PT_PHDR", path); 778 return NULL; 779 } 780 obj->phdr = (const Elf_Phdr *) ph->p_vaddr; 781 obj->phsize = ph->p_memsz; 782 break; 783 784 case PT_INTERP: 785 obj->interp = (const char *) ph->p_vaddr; 786 break; 787 788 case PT_LOAD: 789 if (nsegs == 0) { /* First load segment */ 790 obj->vaddrbase = trunc_page(ph->p_vaddr); 791 obj->mapbase = (caddr_t) obj->vaddrbase; 792 obj->relocbase = obj->mapbase - obj->vaddrbase; 793 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 794 obj->vaddrbase; 795 } else { /* Last load segment */ 796 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 797 obj->vaddrbase; 798 } 799 nsegs++; 800 break; 801 802 case PT_DYNAMIC: 803 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; 804 break; 805 806 case PT_TLS: 807 obj->tlsindex = 1; 808 obj->tlssize = ph->p_memsz; 809 obj->tlsalign = ph->p_align; 810 obj->tlsinitsize = ph->p_filesz; 811 obj->tlsinit = (void*) ph->p_vaddr; 812 break; 813 } 814 } 815 if (nsegs < 1) { 816 _rtld_error("%s: too few PT_LOAD segments", path); 817 return NULL; 818 } 819 820 obj->entry = entry; 821 return obj; 822 } 823 824 static Obj_Entry * 825 dlcheck(void *handle) 826 { 827 Obj_Entry *obj; 828 829 for (obj = obj_list; obj != NULL; obj = obj->next) 830 if (obj == (Obj_Entry *) handle) 831 break; 832 833 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 834 _rtld_error("Invalid shared object handle %p", handle); 835 return NULL; 836 } 837 return obj; 838 } 839 840 /* 841 * If the given object is already in the donelist, return true. Otherwise 842 * add the object to the list and return false. 843 */ 844 static bool 845 donelist_check(DoneList *dlp, const Obj_Entry *obj) 846 { 847 unsigned int i; 848 849 for (i = 0; i < dlp->num_used; i++) 850 if (dlp->objs[i] == obj) 851 return true; 852 /* 853 * Our donelist allocation should always be sufficient. But if 854 * our threads locking isn't working properly, more shared objects 855 * could have been loaded since we allocated the list. That should 856 * never happen, but we'll handle it properly just in case it does. 857 */ 858 if (dlp->num_used < dlp->num_alloc) 859 dlp->objs[dlp->num_used++] = obj; 860 return false; 861 } 862 863 /* 864 * Hash function for symbol table lookup. Don't even think about changing 865 * this. It is specified by the System V ABI. 866 */ 867 unsigned long 868 elf_hash(const char *name) 869 { 870 const unsigned char *p = (const unsigned char *) name; 871 unsigned long h = 0; 872 unsigned long g; 873 874 while (*p != '\0') { 875 h = (h << 4) + *p++; 876 if ((g = h & 0xf0000000) != 0) 877 h ^= g >> 24; 878 h &= ~g; 879 } 880 return h; 881 } 882 883 /* 884 * Find the library with the given name, and return its full pathname. 885 * The returned string is dynamically allocated. Generates an error 886 * message and returns NULL if the library cannot be found. 887 * 888 * If the second argument is non-NULL, then it refers to an already- 889 * loaded shared object, whose library search path will be searched. 890 * 891 * The search order is: 892 * LD_LIBRARY_PATH 893 * rpath in the referencing file 894 * ldconfig hints 895 * /lib:/usr/lib 896 */ 897 static char * 898 find_library(const char *xname, const Obj_Entry *refobj) 899 { 900 char *pathname; 901 char *name; 902 903 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 904 if (xname[0] != '/' && !trust) { 905 _rtld_error("Absolute pathname required for shared object \"%s\"", 906 xname); 907 return NULL; 908 } 909 return xstrdup(xname); 910 } 911 912 if (libmap_disable || (refobj == NULL) || 913 (name = lm_find(refobj->path, xname)) == NULL) 914 name = (char *)xname; 915 916 dbg(" Searching for \"%s\"", name); 917 918 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 919 (refobj != NULL && 920 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 921 (pathname = search_library_path(name, gethints())) != NULL || 922 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 923 return pathname; 924 925 if(refobj != NULL && refobj->path != NULL) { 926 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 927 name, basename(refobj->path)); 928 } else { 929 _rtld_error("Shared object \"%s\" not found", name); 930 } 931 return NULL; 932 } 933 934 /* 935 * Given a symbol number in a referencing object, find the corresponding 936 * definition of the symbol. Returns a pointer to the symbol, or NULL if 937 * no definition was found. Returns a pointer to the Obj_Entry of the 938 * defining object via the reference parameter DEFOBJ_OUT. 939 */ 940 const Elf_Sym * 941 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 942 const Obj_Entry **defobj_out, int flags, SymCache *cache) 943 { 944 const Elf_Sym *ref; 945 const Elf_Sym *def; 946 const Obj_Entry *defobj; 947 const Ver_Entry *ventry; 948 const char *name; 949 unsigned long hash; 950 951 /* 952 * If we have already found this symbol, get the information from 953 * the cache. 954 */ 955 if (symnum >= refobj->nchains) 956 return NULL; /* Bad object */ 957 if (cache != NULL && cache[symnum].sym != NULL) { 958 *defobj_out = cache[symnum].obj; 959 return cache[symnum].sym; 960 } 961 962 ref = refobj->symtab + symnum; 963 name = refobj->strtab + ref->st_name; 964 defobj = NULL; 965 966 /* 967 * We don't have to do a full scale lookup if the symbol is local. 968 * We know it will bind to the instance in this load module; to 969 * which we already have a pointer (ie ref). By not doing a lookup, 970 * we not only improve performance, but it also avoids unresolvable 971 * symbols when local symbols are not in the hash table. This has 972 * been seen with the ia64 toolchain. 973 */ 974 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 975 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 976 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 977 symnum); 978 } 979 ventry = fetch_ventry(refobj, symnum); 980 hash = elf_hash(name); 981 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 982 } else { 983 def = ref; 984 defobj = refobj; 985 } 986 987 /* 988 * If we found no definition and the reference is weak, treat the 989 * symbol as having the value zero. 990 */ 991 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 992 def = &sym_zero; 993 defobj = obj_main; 994 } 995 996 if (def != NULL) { 997 *defobj_out = defobj; 998 /* Record the information in the cache to avoid subsequent lookups. */ 999 if (cache != NULL) { 1000 cache[symnum].sym = def; 1001 cache[symnum].obj = defobj; 1002 } 1003 } else { 1004 if (refobj != &obj_rtld) 1005 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1006 } 1007 return def; 1008 } 1009 1010 /* 1011 * Return the search path from the ldconfig hints file, reading it if 1012 * necessary. Returns NULL if there are problems with the hints file, 1013 * or if the search path there is empty. 1014 */ 1015 static const char * 1016 gethints(void) 1017 { 1018 static char *hints; 1019 1020 if (hints == NULL) { 1021 int fd; 1022 struct elfhints_hdr hdr; 1023 char *p; 1024 1025 /* Keep from trying again in case the hints file is bad. */ 1026 hints = ""; 1027 1028 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1) 1029 return NULL; 1030 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1031 hdr.magic != ELFHINTS_MAGIC || 1032 hdr.version != 1) { 1033 close(fd); 1034 return NULL; 1035 } 1036 p = xmalloc(hdr.dirlistlen + 1); 1037 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1038 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1039 free(p); 1040 close(fd); 1041 return NULL; 1042 } 1043 hints = p; 1044 close(fd); 1045 } 1046 return hints[0] != '\0' ? hints : NULL; 1047 } 1048 1049 static void 1050 init_dag(Obj_Entry *root) 1051 { 1052 DoneList donelist; 1053 1054 donelist_init(&donelist); 1055 init_dag1(root, root, &donelist); 1056 } 1057 1058 static void 1059 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1060 { 1061 const Needed_Entry *needed; 1062 1063 if (donelist_check(dlp, obj)) 1064 return; 1065 1066 obj->refcount++; 1067 objlist_push_tail(&obj->dldags, root); 1068 objlist_push_tail(&root->dagmembers, obj); 1069 for (needed = obj->needed; needed != NULL; needed = needed->next) 1070 if (needed->obj != NULL) 1071 init_dag1(root, needed->obj, dlp); 1072 } 1073 1074 /* 1075 * Initialize the dynamic linker. The argument is the address at which 1076 * the dynamic linker has been mapped into memory. The primary task of 1077 * this function is to relocate the dynamic linker. 1078 */ 1079 static void 1080 init_rtld(caddr_t mapbase) 1081 { 1082 Obj_Entry objtmp; /* Temporary rtld object */ 1083 1084 /* 1085 * Conjure up an Obj_Entry structure for the dynamic linker. 1086 * 1087 * The "path" member can't be initialized yet because string constatns 1088 * cannot yet be acessed. Below we will set it correctly. 1089 */ 1090 memset(&objtmp, 0, sizeof(objtmp)); 1091 objtmp.path = NULL; 1092 objtmp.rtld = true; 1093 objtmp.mapbase = mapbase; 1094 #ifdef PIC 1095 objtmp.relocbase = mapbase; 1096 #endif 1097 if (RTLD_IS_DYNAMIC()) { 1098 objtmp.dynamic = rtld_dynamic(&objtmp); 1099 digest_dynamic(&objtmp, 1); 1100 assert(objtmp.needed == NULL); 1101 assert(!objtmp.textrel); 1102 1103 /* 1104 * Temporarily put the dynamic linker entry into the object list, so 1105 * that symbols can be found. 1106 */ 1107 1108 relocate_objects(&objtmp, true, &objtmp); 1109 } 1110 1111 /* Initialize the object list. */ 1112 obj_tail = &obj_list; 1113 1114 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1115 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1116 1117 /* Replace the path with a dynamically allocated copy. */ 1118 obj_rtld.path = xstrdup(PATH_RTLD); 1119 1120 r_debug.r_brk = r_debug_state; 1121 r_debug.r_state = RT_CONSISTENT; 1122 } 1123 1124 /* 1125 * Add the init functions from a needed object list (and its recursive 1126 * needed objects) to "list". This is not used directly; it is a helper 1127 * function for initlist_add_objects(). The write lock must be held 1128 * when this function is called. 1129 */ 1130 static void 1131 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1132 { 1133 /* Recursively process the successor needed objects. */ 1134 if (needed->next != NULL) 1135 initlist_add_neededs(needed->next, list); 1136 1137 /* Process the current needed object. */ 1138 if (needed->obj != NULL) 1139 initlist_add_objects(needed->obj, &needed->obj->next, list); 1140 } 1141 1142 /* 1143 * Scan all of the DAGs rooted in the range of objects from "obj" to 1144 * "tail" and add their init functions to "list". This recurses over 1145 * the DAGs and ensure the proper init ordering such that each object's 1146 * needed libraries are initialized before the object itself. At the 1147 * same time, this function adds the objects to the global finalization 1148 * list "list_fini" in the opposite order. The write lock must be 1149 * held when this function is called. 1150 */ 1151 static void 1152 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1153 { 1154 if (obj->init_done) 1155 return; 1156 obj->init_done = true; 1157 1158 /* Recursively process the successor objects. */ 1159 if (&obj->next != tail) 1160 initlist_add_objects(obj->next, tail, list); 1161 1162 /* Recursively process the needed objects. */ 1163 if (obj->needed != NULL) 1164 initlist_add_neededs(obj->needed, list); 1165 1166 /* Add the object to the init list. */ 1167 if (obj->init != (Elf_Addr)NULL) 1168 objlist_push_tail(list, obj); 1169 1170 /* Add the object to the global fini list in the reverse order. */ 1171 if (obj->fini != (Elf_Addr)NULL) 1172 objlist_push_head(&list_fini, obj); 1173 } 1174 1175 #ifndef FPTR_TARGET 1176 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1177 #endif 1178 1179 static bool 1180 is_exported(const Elf_Sym *def) 1181 { 1182 Elf_Addr value; 1183 const func_ptr_type *p; 1184 1185 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1186 for (p = exports; *p != NULL; p++) 1187 if (FPTR_TARGET(*p) == value) 1188 return true; 1189 return false; 1190 } 1191 1192 /* 1193 * Given a shared object, traverse its list of needed objects, and load 1194 * each of them. Returns 0 on success. Generates an error message and 1195 * returns -1 on failure. 1196 */ 1197 static int 1198 load_needed_objects(Obj_Entry *first) 1199 { 1200 Obj_Entry *obj; 1201 1202 for (obj = first; obj != NULL; obj = obj->next) { 1203 Needed_Entry *needed; 1204 1205 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1206 needed->obj = load_object(obj->strtab + needed->name, obj); 1207 if (needed->obj == NULL && !ld_tracing) 1208 return -1; 1209 } 1210 } 1211 1212 return 0; 1213 } 1214 1215 static int 1216 load_preload_objects(void) 1217 { 1218 char *p = ld_preload; 1219 static const char delim[] = " \t:;"; 1220 1221 if (p == NULL) 1222 return 0; 1223 1224 p += strspn(p, delim); 1225 while (*p != '\0') { 1226 size_t len = strcspn(p, delim); 1227 char savech; 1228 1229 savech = p[len]; 1230 p[len] = '\0'; 1231 if (load_object(p, NULL) == NULL) 1232 return -1; /* XXX - cleanup */ 1233 p[len] = savech; 1234 p += len; 1235 p += strspn(p, delim); 1236 } 1237 return 0; 1238 } 1239 1240 /* 1241 * Load a shared object into memory, if it is not already loaded. 1242 * 1243 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1244 * on failure. 1245 */ 1246 static Obj_Entry * 1247 load_object(const char *name, const Obj_Entry *refobj) 1248 { 1249 Obj_Entry *obj; 1250 int fd = -1; 1251 struct stat sb; 1252 char *path; 1253 1254 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1255 if (object_match_name(obj, name)) 1256 return obj; 1257 1258 path = find_library(name, refobj); 1259 if (path == NULL) 1260 return NULL; 1261 1262 /* 1263 * If we didn't find a match by pathname, open the file and check 1264 * again by device and inode. This avoids false mismatches caused 1265 * by multiple links or ".." in pathnames. 1266 * 1267 * To avoid a race, we open the file and use fstat() rather than 1268 * using stat(). 1269 */ 1270 if ((fd = open(path, O_RDONLY)) == -1) { 1271 _rtld_error("Cannot open \"%s\"", path); 1272 free(path); 1273 return NULL; 1274 } 1275 if (fstat(fd, &sb) == -1) { 1276 _rtld_error("Cannot fstat \"%s\"", path); 1277 close(fd); 1278 free(path); 1279 return NULL; 1280 } 1281 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1282 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1283 close(fd); 1284 break; 1285 } 1286 } 1287 if (obj != NULL) { 1288 object_add_name(obj, name); 1289 free(path); 1290 close(fd); 1291 return obj; 1292 } 1293 1294 /* First use of this object, so we must map it in */ 1295 obj = do_load_object(fd, name, path, &sb); 1296 if (obj == NULL) 1297 free(path); 1298 close(fd); 1299 1300 return obj; 1301 } 1302 1303 static Obj_Entry * 1304 do_load_object(int fd, const char *name, char *path, struct stat *sbp) 1305 { 1306 Obj_Entry *obj; 1307 struct statfs fs; 1308 1309 /* 1310 * but first, make sure that environment variables haven't been 1311 * used to circumvent the noexec flag on a filesystem. 1312 */ 1313 if (dangerous_ld_env) { 1314 if (fstatfs(fd, &fs) != 0) { 1315 _rtld_error("Cannot fstatfs \"%s\"", path); 1316 return NULL; 1317 } 1318 if (fs.f_flags & MNT_NOEXEC) { 1319 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1320 return NULL; 1321 } 1322 } 1323 dbg("loading \"%s\"", path); 1324 obj = map_object(fd, path, sbp); 1325 if (obj == NULL) 1326 return NULL; 1327 1328 object_add_name(obj, name); 1329 obj->path = path; 1330 digest_dynamic(obj, 0); 1331 1332 *obj_tail = obj; 1333 obj_tail = &obj->next; 1334 obj_count++; 1335 linkmap_add(obj); /* for GDB & dlinfo() */ 1336 1337 dbg(" %p .. %p: %s", obj->mapbase, 1338 obj->mapbase + obj->mapsize - 1, obj->path); 1339 if (obj->textrel) 1340 dbg(" WARNING: %s has impure text", obj->path); 1341 1342 return obj; 1343 } 1344 1345 static Obj_Entry * 1346 obj_from_addr(const void *addr) 1347 { 1348 Obj_Entry *obj; 1349 1350 for (obj = obj_list; obj != NULL; obj = obj->next) { 1351 if (addr < (void *) obj->mapbase) 1352 continue; 1353 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1354 return obj; 1355 } 1356 return NULL; 1357 } 1358 1359 /* 1360 * Call the finalization functions for each of the objects in "list" 1361 * which are unreferenced. All of the objects are expected to have 1362 * non-NULL fini functions. 1363 */ 1364 static void 1365 objlist_call_fini(Objlist *list) 1366 { 1367 Objlist_Entry *elm; 1368 char *saved_msg; 1369 1370 /* 1371 * Preserve the current error message since a fini function might 1372 * call into the dynamic linker and overwrite it. 1373 */ 1374 saved_msg = errmsg_save(); 1375 STAILQ_FOREACH(elm, list, link) { 1376 if (elm->obj->refcount == 0) { 1377 dbg("calling fini function for %s at %p", elm->obj->path, 1378 (void *)elm->obj->fini); 1379 call_initfini_pointer(elm->obj, elm->obj->fini); 1380 } 1381 } 1382 errmsg_restore(saved_msg); 1383 } 1384 1385 /* 1386 * Call the initialization functions for each of the objects in 1387 * "list". All of the objects are expected to have non-NULL init 1388 * functions. 1389 */ 1390 static void 1391 objlist_call_init(Objlist *list) 1392 { 1393 Objlist_Entry *elm; 1394 char *saved_msg; 1395 1396 /* 1397 * Preserve the current error message since an init function might 1398 * call into the dynamic linker and overwrite it. 1399 */ 1400 saved_msg = errmsg_save(); 1401 STAILQ_FOREACH(elm, list, link) { 1402 dbg("calling init function for %s at %p", elm->obj->path, 1403 (void *)elm->obj->init); 1404 call_initfini_pointer(elm->obj, elm->obj->init); 1405 } 1406 errmsg_restore(saved_msg); 1407 } 1408 1409 static void 1410 objlist_clear(Objlist *list) 1411 { 1412 Objlist_Entry *elm; 1413 1414 while (!STAILQ_EMPTY(list)) { 1415 elm = STAILQ_FIRST(list); 1416 STAILQ_REMOVE_HEAD(list, link); 1417 free(elm); 1418 } 1419 } 1420 1421 static Objlist_Entry * 1422 objlist_find(Objlist *list, const Obj_Entry *obj) 1423 { 1424 Objlist_Entry *elm; 1425 1426 STAILQ_FOREACH(elm, list, link) 1427 if (elm->obj == obj) 1428 return elm; 1429 return NULL; 1430 } 1431 1432 static void 1433 objlist_init(Objlist *list) 1434 { 1435 STAILQ_INIT(list); 1436 } 1437 1438 static void 1439 objlist_push_head(Objlist *list, Obj_Entry *obj) 1440 { 1441 Objlist_Entry *elm; 1442 1443 elm = NEW(Objlist_Entry); 1444 elm->obj = obj; 1445 STAILQ_INSERT_HEAD(list, elm, link); 1446 } 1447 1448 static void 1449 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1450 { 1451 Objlist_Entry *elm; 1452 1453 elm = NEW(Objlist_Entry); 1454 elm->obj = obj; 1455 STAILQ_INSERT_TAIL(list, elm, link); 1456 } 1457 1458 static void 1459 objlist_remove(Objlist *list, Obj_Entry *obj) 1460 { 1461 Objlist_Entry *elm; 1462 1463 if ((elm = objlist_find(list, obj)) != NULL) { 1464 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1465 free(elm); 1466 } 1467 } 1468 1469 /* 1470 * Remove all of the unreferenced objects from "list". 1471 */ 1472 static void 1473 objlist_remove_unref(Objlist *list) 1474 { 1475 Objlist newlist; 1476 Objlist_Entry *elm; 1477 1478 STAILQ_INIT(&newlist); 1479 while (!STAILQ_EMPTY(list)) { 1480 elm = STAILQ_FIRST(list); 1481 STAILQ_REMOVE_HEAD(list, link); 1482 if (elm->obj->refcount == 0) 1483 free(elm); 1484 else 1485 STAILQ_INSERT_TAIL(&newlist, elm, link); 1486 } 1487 *list = newlist; 1488 } 1489 1490 /* 1491 * Relocate newly-loaded shared objects. The argument is a pointer to 1492 * the Obj_Entry for the first such object. All objects from the first 1493 * to the end of the list of objects are relocated. Returns 0 on success, 1494 * or -1 on failure. 1495 */ 1496 static int 1497 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1498 { 1499 Obj_Entry *obj; 1500 1501 for (obj = first; obj != NULL; obj = obj->next) { 1502 if (obj != rtldobj) 1503 dbg("relocating \"%s\"", obj->path); 1504 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1505 obj->symtab == NULL || obj->strtab == NULL) { 1506 _rtld_error("%s: Shared object has no run-time symbol table", 1507 obj->path); 1508 return -1; 1509 } 1510 1511 if (obj->textrel) { 1512 /* There are relocations to the write-protected text segment. */ 1513 if (mprotect(obj->mapbase, obj->textsize, 1514 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1515 _rtld_error("%s: Cannot write-enable text segment: %s", 1516 obj->path, strerror(errno)); 1517 return -1; 1518 } 1519 } 1520 1521 /* Process the non-PLT relocations. */ 1522 if (reloc_non_plt(obj, rtldobj)) 1523 return -1; 1524 1525 if (obj->textrel) { /* Re-protected the text segment. */ 1526 if (mprotect(obj->mapbase, obj->textsize, 1527 PROT_READ|PROT_EXEC) == -1) { 1528 _rtld_error("%s: Cannot write-protect text segment: %s", 1529 obj->path, strerror(errno)); 1530 return -1; 1531 } 1532 } 1533 1534 /* Process the PLT relocations. */ 1535 if (reloc_plt(obj) == -1) 1536 return -1; 1537 /* Relocate the jump slots if we are doing immediate binding. */ 1538 if (obj->bind_now || bind_now) 1539 if (reloc_jmpslots(obj) == -1) 1540 return -1; 1541 1542 1543 /* 1544 * Set up the magic number and version in the Obj_Entry. These 1545 * were checked in the crt1.o from the original ElfKit, so we 1546 * set them for backward compatibility. 1547 */ 1548 obj->magic = RTLD_MAGIC; 1549 obj->version = RTLD_VERSION; 1550 1551 /* Set the special PLT or GOT entries. */ 1552 init_pltgot(obj); 1553 } 1554 1555 return 0; 1556 } 1557 1558 /* 1559 * Cleanup procedure. It will be called (by the atexit mechanism) just 1560 * before the process exits. 1561 */ 1562 static void 1563 rtld_exit(void) 1564 { 1565 Obj_Entry *obj; 1566 1567 dbg("rtld_exit()"); 1568 /* Clear all the reference counts so the fini functions will be called. */ 1569 for (obj = obj_list; obj != NULL; obj = obj->next) 1570 obj->refcount = 0; 1571 objlist_call_fini(&list_fini); 1572 /* No need to remove the items from the list, since we are exiting. */ 1573 if (!libmap_disable) 1574 lm_fini(); 1575 } 1576 1577 static void * 1578 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1579 { 1580 #ifdef COMPAT_32BIT 1581 const char *trans; 1582 #endif 1583 if (path == NULL) 1584 return (NULL); 1585 1586 path += strspn(path, ":;"); 1587 while (*path != '\0') { 1588 size_t len; 1589 char *res; 1590 1591 len = strcspn(path, ":;"); 1592 #ifdef COMPAT_32BIT 1593 trans = lm_findn(NULL, path, len); 1594 if (trans) 1595 res = callback(trans, strlen(trans), arg); 1596 else 1597 #endif 1598 res = callback(path, len, arg); 1599 1600 if (res != NULL) 1601 return (res); 1602 1603 path += len; 1604 path += strspn(path, ":;"); 1605 } 1606 1607 return (NULL); 1608 } 1609 1610 struct try_library_args { 1611 const char *name; 1612 size_t namelen; 1613 char *buffer; 1614 size_t buflen; 1615 }; 1616 1617 static void * 1618 try_library_path(const char *dir, size_t dirlen, void *param) 1619 { 1620 struct try_library_args *arg; 1621 1622 arg = param; 1623 if (*dir == '/' || trust) { 1624 char *pathname; 1625 1626 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1627 return (NULL); 1628 1629 pathname = arg->buffer; 1630 strncpy(pathname, dir, dirlen); 1631 pathname[dirlen] = '/'; 1632 strcpy(pathname + dirlen + 1, arg->name); 1633 1634 dbg(" Trying \"%s\"", pathname); 1635 if (access(pathname, F_OK) == 0) { /* We found it */ 1636 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1637 strcpy(pathname, arg->buffer); 1638 return (pathname); 1639 } 1640 } 1641 return (NULL); 1642 } 1643 1644 static char * 1645 search_library_path(const char *name, const char *path) 1646 { 1647 char *p; 1648 struct try_library_args arg; 1649 1650 if (path == NULL) 1651 return NULL; 1652 1653 arg.name = name; 1654 arg.namelen = strlen(name); 1655 arg.buffer = xmalloc(PATH_MAX); 1656 arg.buflen = PATH_MAX; 1657 1658 p = path_enumerate(path, try_library_path, &arg); 1659 1660 free(arg.buffer); 1661 1662 return (p); 1663 } 1664 1665 int 1666 dlclose(void *handle) 1667 { 1668 Obj_Entry *root; 1669 int lockstate; 1670 1671 lockstate = wlock_acquire(rtld_bind_lock); 1672 root = dlcheck(handle); 1673 if (root == NULL) { 1674 wlock_release(rtld_bind_lock, lockstate); 1675 return -1; 1676 } 1677 1678 /* Unreference the object and its dependencies. */ 1679 root->dl_refcount--; 1680 1681 unref_dag(root); 1682 1683 if (root->refcount == 0) { 1684 /* 1685 * The object is no longer referenced, so we must unload it. 1686 * First, call the fini functions with no locks held. 1687 */ 1688 wlock_release(rtld_bind_lock, lockstate); 1689 objlist_call_fini(&list_fini); 1690 lockstate = wlock_acquire(rtld_bind_lock); 1691 objlist_remove_unref(&list_fini); 1692 1693 /* Finish cleaning up the newly-unreferenced objects. */ 1694 GDB_STATE(RT_DELETE,&root->linkmap); 1695 unload_object(root); 1696 GDB_STATE(RT_CONSISTENT,NULL); 1697 } 1698 wlock_release(rtld_bind_lock, lockstate); 1699 return 0; 1700 } 1701 1702 const char * 1703 dlerror(void) 1704 { 1705 char *msg = error_message; 1706 error_message = NULL; 1707 return msg; 1708 } 1709 1710 /* 1711 * This function is deprecated and has no effect. 1712 */ 1713 void 1714 dllockinit(void *context, 1715 void *(*lock_create)(void *context), 1716 void (*rlock_acquire)(void *lock), 1717 void (*wlock_acquire)(void *lock), 1718 void (*lock_release)(void *lock), 1719 void (*lock_destroy)(void *lock), 1720 void (*context_destroy)(void *context)) 1721 { 1722 static void *cur_context; 1723 static void (*cur_context_destroy)(void *); 1724 1725 /* Just destroy the context from the previous call, if necessary. */ 1726 if (cur_context_destroy != NULL) 1727 cur_context_destroy(cur_context); 1728 cur_context = context; 1729 cur_context_destroy = context_destroy; 1730 } 1731 1732 void * 1733 dlopen(const char *name, int mode) 1734 { 1735 Obj_Entry **old_obj_tail; 1736 Obj_Entry *obj; 1737 Objlist initlist; 1738 int result, lockstate; 1739 1740 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1741 if (ld_tracing != NULL) 1742 environ = (char **)*get_program_var_addr("environ"); 1743 1744 objlist_init(&initlist); 1745 1746 lockstate = wlock_acquire(rtld_bind_lock); 1747 GDB_STATE(RT_ADD,NULL); 1748 1749 old_obj_tail = obj_tail; 1750 obj = NULL; 1751 if (name == NULL) { 1752 obj = obj_main; 1753 obj->refcount++; 1754 } else { 1755 obj = load_object(name, obj_main); 1756 } 1757 1758 if (obj) { 1759 obj->dl_refcount++; 1760 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 1761 objlist_push_tail(&list_global, obj); 1762 mode &= RTLD_MODEMASK; 1763 if (*old_obj_tail != NULL) { /* We loaded something new. */ 1764 assert(*old_obj_tail == obj); 1765 result = load_needed_objects(obj); 1766 init_dag(obj); 1767 if (result != -1) 1768 result = rtld_verify_versions(&obj->dagmembers); 1769 if (result != -1 && ld_tracing) 1770 goto trace; 1771 if (result == -1 || 1772 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 1773 obj->dl_refcount--; 1774 unref_dag(obj); 1775 if (obj->refcount == 0) 1776 unload_object(obj); 1777 obj = NULL; 1778 } else { 1779 /* Make list of init functions to call. */ 1780 initlist_add_objects(obj, &obj->next, &initlist); 1781 } 1782 } else { 1783 1784 /* Bump the reference counts for objects on this DAG. */ 1785 ref_dag(obj); 1786 1787 if (ld_tracing) 1788 goto trace; 1789 } 1790 } 1791 1792 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 1793 1794 /* Call the init functions with no locks held. */ 1795 wlock_release(rtld_bind_lock, lockstate); 1796 objlist_call_init(&initlist); 1797 lockstate = wlock_acquire(rtld_bind_lock); 1798 objlist_clear(&initlist); 1799 wlock_release(rtld_bind_lock, lockstate); 1800 return obj; 1801 trace: 1802 trace_loaded_objects(obj); 1803 wlock_release(rtld_bind_lock, lockstate); 1804 exit(0); 1805 } 1806 1807 static void * 1808 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 1809 int flags) 1810 { 1811 const Obj_Entry *obj; 1812 unsigned long hash; 1813 const Elf_Sym *def; 1814 const Obj_Entry *defobj; 1815 int lockstate; 1816 1817 hash = elf_hash(name); 1818 def = NULL; 1819 defobj = NULL; 1820 flags |= SYMLOOK_IN_PLT; 1821 1822 lockstate = rlock_acquire(rtld_bind_lock); 1823 if (handle == NULL || handle == RTLD_NEXT || 1824 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 1825 1826 if ((obj = obj_from_addr(retaddr)) == NULL) { 1827 _rtld_error("Cannot determine caller's shared object"); 1828 rlock_release(rtld_bind_lock, lockstate); 1829 return NULL; 1830 } 1831 if (handle == NULL) { /* Just the caller's shared object. */ 1832 def = symlook_obj(name, hash, obj, ve, flags); 1833 defobj = obj; 1834 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 1835 handle == RTLD_SELF) { /* ... caller included */ 1836 if (handle == RTLD_NEXT) 1837 obj = obj->next; 1838 for (; obj != NULL; obj = obj->next) { 1839 if ((def = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 1840 defobj = obj; 1841 break; 1842 } 1843 } 1844 } else { 1845 assert(handle == RTLD_DEFAULT); 1846 def = symlook_default(name, hash, obj, &defobj, ve, flags); 1847 } 1848 } else { 1849 if ((obj = dlcheck(handle)) == NULL) { 1850 rlock_release(rtld_bind_lock, lockstate); 1851 return NULL; 1852 } 1853 1854 if (obj->mainprog) { 1855 DoneList donelist; 1856 1857 /* Search main program and all libraries loaded by it. */ 1858 donelist_init(&donelist); 1859 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 1860 &donelist); 1861 } else { 1862 /* 1863 * XXX - This isn't correct. The search should include the whole 1864 * DAG rooted at the given object. 1865 */ 1866 def = symlook_obj(name, hash, obj, ve, flags); 1867 defobj = obj; 1868 } 1869 } 1870 1871 if (def != NULL) { 1872 rlock_release(rtld_bind_lock, lockstate); 1873 1874 /* 1875 * The value required by the caller is derived from the value 1876 * of the symbol. For the ia64 architecture, we need to 1877 * construct a function descriptor which the caller can use to 1878 * call the function with the right 'gp' value. For other 1879 * architectures and for non-functions, the value is simply 1880 * the relocated value of the symbol. 1881 */ 1882 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 1883 return make_function_pointer(def, defobj); 1884 else 1885 return defobj->relocbase + def->st_value; 1886 } 1887 1888 _rtld_error("Undefined symbol \"%s\"", name); 1889 rlock_release(rtld_bind_lock, lockstate); 1890 return NULL; 1891 } 1892 1893 void * 1894 dlsym(void *handle, const char *name) 1895 { 1896 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 1897 SYMLOOK_DLSYM); 1898 } 1899 1900 void * 1901 dlvsym(void *handle, const char *name, const char *version) 1902 { 1903 Ver_Entry ventry; 1904 1905 ventry.name = version; 1906 ventry.file = NULL; 1907 ventry.hash = elf_hash(version); 1908 ventry.flags= 0; 1909 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 1910 SYMLOOK_DLSYM); 1911 } 1912 1913 int 1914 dladdr(const void *addr, Dl_info *info) 1915 { 1916 const Obj_Entry *obj; 1917 const Elf_Sym *def; 1918 void *symbol_addr; 1919 unsigned long symoffset; 1920 int lockstate; 1921 1922 lockstate = rlock_acquire(rtld_bind_lock); 1923 obj = obj_from_addr(addr); 1924 if (obj == NULL) { 1925 _rtld_error("No shared object contains address"); 1926 rlock_release(rtld_bind_lock, lockstate); 1927 return 0; 1928 } 1929 info->dli_fname = obj->path; 1930 info->dli_fbase = obj->mapbase; 1931 info->dli_saddr = (void *)0; 1932 info->dli_sname = NULL; 1933 1934 /* 1935 * Walk the symbol list looking for the symbol whose address is 1936 * closest to the address sent in. 1937 */ 1938 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 1939 def = obj->symtab + symoffset; 1940 1941 /* 1942 * For skip the symbol if st_shndx is either SHN_UNDEF or 1943 * SHN_COMMON. 1944 */ 1945 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 1946 continue; 1947 1948 /* 1949 * If the symbol is greater than the specified address, or if it 1950 * is further away from addr than the current nearest symbol, 1951 * then reject it. 1952 */ 1953 symbol_addr = obj->relocbase + def->st_value; 1954 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 1955 continue; 1956 1957 /* Update our idea of the nearest symbol. */ 1958 info->dli_sname = obj->strtab + def->st_name; 1959 info->dli_saddr = symbol_addr; 1960 1961 /* Exact match? */ 1962 if (info->dli_saddr == addr) 1963 break; 1964 } 1965 rlock_release(rtld_bind_lock, lockstate); 1966 return 1; 1967 } 1968 1969 int 1970 dlinfo(void *handle, int request, void *p) 1971 { 1972 const Obj_Entry *obj; 1973 int error, lockstate; 1974 1975 lockstate = rlock_acquire(rtld_bind_lock); 1976 1977 if (handle == NULL || handle == RTLD_SELF) { 1978 void *retaddr; 1979 1980 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 1981 if ((obj = obj_from_addr(retaddr)) == NULL) 1982 _rtld_error("Cannot determine caller's shared object"); 1983 } else 1984 obj = dlcheck(handle); 1985 1986 if (obj == NULL) { 1987 rlock_release(rtld_bind_lock, lockstate); 1988 return (-1); 1989 } 1990 1991 error = 0; 1992 switch (request) { 1993 case RTLD_DI_LINKMAP: 1994 *((struct link_map const **)p) = &obj->linkmap; 1995 break; 1996 case RTLD_DI_ORIGIN: 1997 error = rtld_dirname(obj->path, p); 1998 break; 1999 2000 case RTLD_DI_SERINFOSIZE: 2001 case RTLD_DI_SERINFO: 2002 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2003 break; 2004 2005 default: 2006 _rtld_error("Invalid request %d passed to dlinfo()", request); 2007 error = -1; 2008 } 2009 2010 rlock_release(rtld_bind_lock, lockstate); 2011 2012 return (error); 2013 } 2014 2015 struct fill_search_info_args { 2016 int request; 2017 unsigned int flags; 2018 Dl_serinfo *serinfo; 2019 Dl_serpath *serpath; 2020 char *strspace; 2021 }; 2022 2023 static void * 2024 fill_search_info(const char *dir, size_t dirlen, void *param) 2025 { 2026 struct fill_search_info_args *arg; 2027 2028 arg = param; 2029 2030 if (arg->request == RTLD_DI_SERINFOSIZE) { 2031 arg->serinfo->dls_cnt ++; 2032 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2033 } else { 2034 struct dl_serpath *s_entry; 2035 2036 s_entry = arg->serpath; 2037 s_entry->dls_name = arg->strspace; 2038 s_entry->dls_flags = arg->flags; 2039 2040 strncpy(arg->strspace, dir, dirlen); 2041 arg->strspace[dirlen] = '\0'; 2042 2043 arg->strspace += dirlen + 1; 2044 arg->serpath++; 2045 } 2046 2047 return (NULL); 2048 } 2049 2050 static int 2051 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2052 { 2053 struct dl_serinfo _info; 2054 struct fill_search_info_args args; 2055 2056 args.request = RTLD_DI_SERINFOSIZE; 2057 args.serinfo = &_info; 2058 2059 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2060 _info.dls_cnt = 0; 2061 2062 path_enumerate(ld_library_path, fill_search_info, &args); 2063 path_enumerate(obj->rpath, fill_search_info, &args); 2064 path_enumerate(gethints(), fill_search_info, &args); 2065 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2066 2067 2068 if (request == RTLD_DI_SERINFOSIZE) { 2069 info->dls_size = _info.dls_size; 2070 info->dls_cnt = _info.dls_cnt; 2071 return (0); 2072 } 2073 2074 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2075 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2076 return (-1); 2077 } 2078 2079 args.request = RTLD_DI_SERINFO; 2080 args.serinfo = info; 2081 args.serpath = &info->dls_serpath[0]; 2082 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2083 2084 args.flags = LA_SER_LIBPATH; 2085 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2086 return (-1); 2087 2088 args.flags = LA_SER_RUNPATH; 2089 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2090 return (-1); 2091 2092 args.flags = LA_SER_CONFIG; 2093 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2094 return (-1); 2095 2096 args.flags = LA_SER_DEFAULT; 2097 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2098 return (-1); 2099 return (0); 2100 } 2101 2102 static int 2103 rtld_dirname(const char *path, char *bname) 2104 { 2105 const char *endp; 2106 2107 /* Empty or NULL string gets treated as "." */ 2108 if (path == NULL || *path == '\0') { 2109 bname[0] = '.'; 2110 bname[1] = '\0'; 2111 return (0); 2112 } 2113 2114 /* Strip trailing slashes */ 2115 endp = path + strlen(path) - 1; 2116 while (endp > path && *endp == '/') 2117 endp--; 2118 2119 /* Find the start of the dir */ 2120 while (endp > path && *endp != '/') 2121 endp--; 2122 2123 /* Either the dir is "/" or there are no slashes */ 2124 if (endp == path) { 2125 bname[0] = *endp == '/' ? '/' : '.'; 2126 bname[1] = '\0'; 2127 return (0); 2128 } else { 2129 do { 2130 endp--; 2131 } while (endp > path && *endp == '/'); 2132 } 2133 2134 if (endp - path + 2 > PATH_MAX) 2135 { 2136 _rtld_error("Filename is too long: %s", path); 2137 return(-1); 2138 } 2139 2140 strncpy(bname, path, endp - path + 1); 2141 bname[endp - path + 1] = '\0'; 2142 return (0); 2143 } 2144 2145 static void 2146 linkmap_add(Obj_Entry *obj) 2147 { 2148 struct link_map *l = &obj->linkmap; 2149 struct link_map *prev; 2150 2151 obj->linkmap.l_name = obj->path; 2152 obj->linkmap.l_addr = obj->mapbase; 2153 obj->linkmap.l_ld = obj->dynamic; 2154 #ifdef __mips__ 2155 /* GDB needs load offset on MIPS to use the symbols */ 2156 obj->linkmap.l_offs = obj->relocbase; 2157 #endif 2158 2159 if (r_debug.r_map == NULL) { 2160 r_debug.r_map = l; 2161 return; 2162 } 2163 2164 /* 2165 * Scan to the end of the list, but not past the entry for the 2166 * dynamic linker, which we want to keep at the very end. 2167 */ 2168 for (prev = r_debug.r_map; 2169 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2170 prev = prev->l_next) 2171 ; 2172 2173 /* Link in the new entry. */ 2174 l->l_prev = prev; 2175 l->l_next = prev->l_next; 2176 if (l->l_next != NULL) 2177 l->l_next->l_prev = l; 2178 prev->l_next = l; 2179 } 2180 2181 static void 2182 linkmap_delete(Obj_Entry *obj) 2183 { 2184 struct link_map *l = &obj->linkmap; 2185 2186 if (l->l_prev == NULL) { 2187 if ((r_debug.r_map = l->l_next) != NULL) 2188 l->l_next->l_prev = NULL; 2189 return; 2190 } 2191 2192 if ((l->l_prev->l_next = l->l_next) != NULL) 2193 l->l_next->l_prev = l->l_prev; 2194 } 2195 2196 /* 2197 * Function for the debugger to set a breakpoint on to gain control. 2198 * 2199 * The two parameters allow the debugger to easily find and determine 2200 * what the runtime loader is doing and to whom it is doing it. 2201 * 2202 * When the loadhook trap is hit (r_debug_state, set at program 2203 * initialization), the arguments can be found on the stack: 2204 * 2205 * +8 struct link_map *m 2206 * +4 struct r_debug *rd 2207 * +0 RetAddr 2208 */ 2209 void 2210 r_debug_state(struct r_debug* rd, struct link_map *m) 2211 { 2212 } 2213 2214 /* 2215 * Get address of the pointer variable in the main program. 2216 */ 2217 static const void ** 2218 get_program_var_addr(const char *name) 2219 { 2220 const Obj_Entry *obj; 2221 unsigned long hash; 2222 2223 hash = elf_hash(name); 2224 for (obj = obj_main; obj != NULL; obj = obj->next) { 2225 const Elf_Sym *def; 2226 2227 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2228 const void **addr; 2229 2230 addr = (const void **)(obj->relocbase + def->st_value); 2231 return addr; 2232 } 2233 } 2234 return NULL; 2235 } 2236 2237 /* 2238 * Set a pointer variable in the main program to the given value. This 2239 * is used to set key variables such as "environ" before any of the 2240 * init functions are called. 2241 */ 2242 static void 2243 set_program_var(const char *name, const void *value) 2244 { 2245 const void **addr; 2246 2247 if ((addr = get_program_var_addr(name)) != NULL) { 2248 dbg("\"%s\": *%p <-- %p", name, addr, value); 2249 *addr = value; 2250 } 2251 } 2252 2253 /* 2254 * Given a symbol name in a referencing object, find the corresponding 2255 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2256 * no definition was found. Returns a pointer to the Obj_Entry of the 2257 * defining object via the reference parameter DEFOBJ_OUT. 2258 */ 2259 static const Elf_Sym * 2260 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2261 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2262 { 2263 DoneList donelist; 2264 const Elf_Sym *def; 2265 const Elf_Sym *symp; 2266 const Obj_Entry *obj; 2267 const Obj_Entry *defobj; 2268 const Objlist_Entry *elm; 2269 def = NULL; 2270 defobj = NULL; 2271 donelist_init(&donelist); 2272 2273 /* Look first in the referencing object if linked symbolically. */ 2274 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2275 symp = symlook_obj(name, hash, refobj, ventry, flags); 2276 if (symp != NULL) { 2277 def = symp; 2278 defobj = refobj; 2279 } 2280 } 2281 2282 /* Search all objects loaded at program start up. */ 2283 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2284 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2285 &donelist); 2286 if (symp != NULL && 2287 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2288 def = symp; 2289 defobj = obj; 2290 } 2291 } 2292 2293 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2294 STAILQ_FOREACH(elm, &list_global, link) { 2295 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2296 break; 2297 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2298 flags, &donelist); 2299 if (symp != NULL && 2300 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2301 def = symp; 2302 defobj = obj; 2303 } 2304 } 2305 2306 /* Search all dlopened DAGs containing the referencing object. */ 2307 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2308 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2309 break; 2310 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2311 flags, &donelist); 2312 if (symp != NULL && 2313 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2314 def = symp; 2315 defobj = obj; 2316 } 2317 } 2318 2319 /* 2320 * Search the dynamic linker itself, and possibly resolve the 2321 * symbol from there. This is how the application links to 2322 * dynamic linker services such as dlopen. Only the values listed 2323 * in the "exports" array can be resolved from the dynamic linker. 2324 */ 2325 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2326 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2327 if (symp != NULL && is_exported(symp)) { 2328 def = symp; 2329 defobj = &obj_rtld; 2330 } 2331 } 2332 2333 if (def != NULL) 2334 *defobj_out = defobj; 2335 return def; 2336 } 2337 2338 static const Elf_Sym * 2339 symlook_list(const char *name, unsigned long hash, Objlist *objlist, 2340 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2341 DoneList *dlp) 2342 { 2343 const Elf_Sym *symp; 2344 const Elf_Sym *def; 2345 const Obj_Entry *defobj; 2346 const Objlist_Entry *elm; 2347 2348 def = NULL; 2349 defobj = NULL; 2350 STAILQ_FOREACH(elm, objlist, link) { 2351 if (donelist_check(dlp, elm->obj)) 2352 continue; 2353 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2354 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2355 def = symp; 2356 defobj = elm->obj; 2357 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2358 break; 2359 } 2360 } 2361 } 2362 if (def != NULL) 2363 *defobj_out = defobj; 2364 return def; 2365 } 2366 2367 /* 2368 * Search the symbol table of a single shared object for a symbol of 2369 * the given name and version, if requested. Returns a pointer to the 2370 * symbol, or NULL if no definition was found. 2371 * 2372 * The symbol's hash value is passed in for efficiency reasons; that 2373 * eliminates many recomputations of the hash value. 2374 */ 2375 const Elf_Sym * 2376 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2377 const Ver_Entry *ventry, int flags) 2378 { 2379 unsigned long symnum; 2380 const Elf_Sym *vsymp; 2381 Elf_Versym verndx; 2382 int vcount; 2383 2384 if (obj->buckets == NULL) 2385 return NULL; 2386 2387 vsymp = NULL; 2388 vcount = 0; 2389 symnum = obj->buckets[hash % obj->nbuckets]; 2390 2391 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2392 const Elf_Sym *symp; 2393 const char *strp; 2394 2395 if (symnum >= obj->nchains) 2396 return NULL; /* Bad object */ 2397 2398 symp = obj->symtab + symnum; 2399 strp = obj->strtab + symp->st_name; 2400 2401 switch (ELF_ST_TYPE(symp->st_info)) { 2402 case STT_FUNC: 2403 case STT_NOTYPE: 2404 case STT_OBJECT: 2405 if (symp->st_value == 0) 2406 continue; 2407 /* fallthrough */ 2408 case STT_TLS: 2409 if (symp->st_shndx != SHN_UNDEF || 2410 ((flags & SYMLOOK_IN_PLT) == 0 && 2411 ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2412 break; 2413 /* fallthrough */ 2414 default: 2415 continue; 2416 } 2417 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2418 continue; 2419 2420 if (ventry == NULL) { 2421 if (obj->versyms != NULL) { 2422 verndx = VER_NDX(obj->versyms[symnum]); 2423 if (verndx > obj->vernum) { 2424 _rtld_error("%s: symbol %s references wrong version %d", 2425 obj->path, obj->strtab + symnum, verndx); 2426 continue; 2427 } 2428 /* 2429 * If we are not called from dlsym (i.e. this is a normal 2430 * relocation from unversioned binary, accept the symbol 2431 * immediately if it happens to have first version after 2432 * this shared object became versioned. Otherwise, if 2433 * symbol is versioned and not hidden, remember it. If it 2434 * is the only symbol with this name exported by the 2435 * shared object, it will be returned as a match at the 2436 * end of the function. If symbol is global (verndx < 2) 2437 * accept it unconditionally. 2438 */ 2439 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2440 return symp; 2441 else if (verndx >= VER_NDX_GIVEN) { 2442 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2443 if (vsymp == NULL) 2444 vsymp = symp; 2445 vcount ++; 2446 } 2447 continue; 2448 } 2449 } 2450 return symp; 2451 } else { 2452 if (obj->versyms == NULL) { 2453 if (object_match_name(obj, ventry->name)) { 2454 _rtld_error("%s: object %s should provide version %s for ", 2455 "symbol %s", obj->path, ventry->name, 2456 obj->strtab + symnum); 2457 continue; 2458 } 2459 } else { 2460 verndx = VER_NDX(obj->versyms[symnum]); 2461 if (verndx > obj->vernum) { 2462 _rtld_error("%s: symbol %s references wrong version %d", 2463 obj->path, obj->strtab + symnum, verndx); 2464 continue; 2465 } 2466 if (obj->vertab[verndx].hash != ventry->hash || 2467 strcmp(obj->vertab[verndx].name, ventry->name)) { 2468 /* 2469 * Version does not match. Look if this is a global symbol 2470 * and if it is not hidden. If global symbol (verndx < 2) 2471 * is available, use it. Do not return symbol if we are 2472 * called by dlvsym, because dlvsym looks for a specific 2473 * version and default one is not what dlvsym wants. 2474 */ 2475 if ((flags & SYMLOOK_DLSYM) || 2476 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2477 (verndx >= VER_NDX_GIVEN)) 2478 continue; 2479 } 2480 } 2481 return symp; 2482 } 2483 } 2484 return (vcount == 1) ? vsymp : NULL; 2485 } 2486 2487 static void 2488 trace_loaded_objects(Obj_Entry *obj) 2489 { 2490 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2491 int c; 2492 2493 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2494 main_local = ""; 2495 2496 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2497 fmt1 = "\t%o => %p (%x)\n"; 2498 2499 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2500 fmt2 = "\t%o (%x)\n"; 2501 2502 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2503 2504 for (; obj; obj = obj->next) { 2505 Needed_Entry *needed; 2506 char *name, *path; 2507 bool is_lib; 2508 2509 if (list_containers && obj->needed != NULL) 2510 printf("%s:\n", obj->path); 2511 for (needed = obj->needed; needed; needed = needed->next) { 2512 if (needed->obj != NULL) { 2513 if (needed->obj->traced && !list_containers) 2514 continue; 2515 needed->obj->traced = true; 2516 path = needed->obj->path; 2517 } else 2518 path = "not found"; 2519 2520 name = (char *)obj->strtab + needed->name; 2521 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2522 2523 fmt = is_lib ? fmt1 : fmt2; 2524 while ((c = *fmt++) != '\0') { 2525 switch (c) { 2526 default: 2527 putchar(c); 2528 continue; 2529 case '\\': 2530 switch (c = *fmt) { 2531 case '\0': 2532 continue; 2533 case 'n': 2534 putchar('\n'); 2535 break; 2536 case 't': 2537 putchar('\t'); 2538 break; 2539 } 2540 break; 2541 case '%': 2542 switch (c = *fmt) { 2543 case '\0': 2544 continue; 2545 case '%': 2546 default: 2547 putchar(c); 2548 break; 2549 case 'A': 2550 printf("%s", main_local); 2551 break; 2552 case 'a': 2553 printf("%s", obj_main->path); 2554 break; 2555 case 'o': 2556 printf("%s", name); 2557 break; 2558 #if 0 2559 case 'm': 2560 printf("%d", sodp->sod_major); 2561 break; 2562 case 'n': 2563 printf("%d", sodp->sod_minor); 2564 break; 2565 #endif 2566 case 'p': 2567 printf("%s", path); 2568 break; 2569 case 'x': 2570 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2571 break; 2572 } 2573 break; 2574 } 2575 ++fmt; 2576 } 2577 } 2578 } 2579 } 2580 2581 /* 2582 * Unload a dlopened object and its dependencies from memory and from 2583 * our data structures. It is assumed that the DAG rooted in the 2584 * object has already been unreferenced, and that the object has a 2585 * reference count of 0. 2586 */ 2587 static void 2588 unload_object(Obj_Entry *root) 2589 { 2590 Obj_Entry *obj; 2591 Obj_Entry **linkp; 2592 2593 assert(root->refcount == 0); 2594 2595 /* 2596 * Pass over the DAG removing unreferenced objects from 2597 * appropriate lists. 2598 */ 2599 unlink_object(root); 2600 2601 /* Unmap all objects that are no longer referenced. */ 2602 linkp = &obj_list->next; 2603 while ((obj = *linkp) != NULL) { 2604 if (obj->refcount == 0) { 2605 dbg("unloading \"%s\"", obj->path); 2606 munmap(obj->mapbase, obj->mapsize); 2607 linkmap_delete(obj); 2608 *linkp = obj->next; 2609 obj_count--; 2610 obj_free(obj); 2611 } else 2612 linkp = &obj->next; 2613 } 2614 obj_tail = linkp; 2615 } 2616 2617 static void 2618 unlink_object(Obj_Entry *root) 2619 { 2620 Objlist_Entry *elm; 2621 2622 if (root->refcount == 0) { 2623 /* Remove the object from the RTLD_GLOBAL list. */ 2624 objlist_remove(&list_global, root); 2625 2626 /* Remove the object from all objects' DAG lists. */ 2627 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2628 objlist_remove(&elm->obj->dldags, root); 2629 if (elm->obj != root) 2630 unlink_object(elm->obj); 2631 } 2632 } 2633 } 2634 2635 static void 2636 ref_dag(Obj_Entry *root) 2637 { 2638 Objlist_Entry *elm; 2639 2640 STAILQ_FOREACH(elm, &root->dagmembers, link) 2641 elm->obj->refcount++; 2642 } 2643 2644 static void 2645 unref_dag(Obj_Entry *root) 2646 { 2647 Objlist_Entry *elm; 2648 2649 STAILQ_FOREACH(elm, &root->dagmembers, link) 2650 elm->obj->refcount--; 2651 } 2652 2653 /* 2654 * Common code for MD __tls_get_addr(). 2655 */ 2656 void * 2657 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 2658 { 2659 Elf_Addr* dtv = *dtvp; 2660 int lockstate; 2661 2662 /* Check dtv generation in case new modules have arrived */ 2663 if (dtv[0] != tls_dtv_generation) { 2664 Elf_Addr* newdtv; 2665 int to_copy; 2666 2667 lockstate = wlock_acquire(rtld_bind_lock); 2668 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 2669 to_copy = dtv[1]; 2670 if (to_copy > tls_max_index) 2671 to_copy = tls_max_index; 2672 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 2673 newdtv[0] = tls_dtv_generation; 2674 newdtv[1] = tls_max_index; 2675 free(dtv); 2676 wlock_release(rtld_bind_lock, lockstate); 2677 *dtvp = newdtv; 2678 } 2679 2680 /* Dynamically allocate module TLS if necessary */ 2681 if (!dtv[index + 1]) { 2682 /* Signal safe, wlock will block out signals. */ 2683 lockstate = wlock_acquire(rtld_bind_lock); 2684 if (!dtv[index + 1]) 2685 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 2686 wlock_release(rtld_bind_lock, lockstate); 2687 } 2688 return (void*) (dtv[index + 1] + offset); 2689 } 2690 2691 /* XXX not sure what variants to use for arm. */ 2692 2693 #if defined(__ia64__) || defined(__alpha__) || defined(__powerpc__) 2694 2695 /* 2696 * Allocate Static TLS using the Variant I method. 2697 */ 2698 void * 2699 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 2700 { 2701 Obj_Entry *obj; 2702 size_t size; 2703 char *tls; 2704 Elf_Addr *dtv, *olddtv; 2705 Elf_Addr addr; 2706 int i; 2707 2708 size = tls_static_space; 2709 2710 tls = malloc(size); 2711 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 2712 2713 *(Elf_Addr**) tls = dtv; 2714 2715 dtv[0] = tls_dtv_generation; 2716 dtv[1] = tls_max_index; 2717 2718 if (oldtls) { 2719 /* 2720 * Copy the static TLS block over whole. 2721 */ 2722 memcpy(tls + tcbsize, oldtls + tcbsize, tls_static_space - tcbsize); 2723 2724 /* 2725 * If any dynamic TLS blocks have been created tls_get_addr(), 2726 * move them over. 2727 */ 2728 olddtv = *(Elf_Addr**) oldtls; 2729 for (i = 0; i < olddtv[1]; i++) { 2730 if (olddtv[i+2] < (Elf_Addr)oldtls || 2731 olddtv[i+2] > (Elf_Addr)oldtls + tls_static_space) { 2732 dtv[i+2] = olddtv[i+2]; 2733 olddtv[i+2] = 0; 2734 } 2735 } 2736 2737 /* 2738 * We assume that all tls blocks are allocated with the same 2739 * size and alignment. 2740 */ 2741 free_tls(oldtls, tcbsize, tcbalign); 2742 } else { 2743 for (obj = objs; obj; obj = obj->next) { 2744 if (obj->tlsoffset) { 2745 addr = (Elf_Addr)tls + obj->tlsoffset; 2746 memset((void*) (addr + obj->tlsinitsize), 2747 0, obj->tlssize - obj->tlsinitsize); 2748 if (obj->tlsinit) 2749 memcpy((void*) addr, obj->tlsinit, 2750 obj->tlsinitsize); 2751 dtv[obj->tlsindex + 1] = addr; 2752 } 2753 } 2754 } 2755 2756 return tls; 2757 } 2758 2759 void 2760 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 2761 { 2762 size_t size; 2763 Elf_Addr* dtv; 2764 int dtvsize, i; 2765 Elf_Addr tlsstart, tlsend; 2766 2767 /* 2768 * Figure out the size of the initial TLS block so that we can 2769 * find stuff which __tls_get_addr() allocated dynamically. 2770 */ 2771 size = tls_static_space; 2772 2773 dtv = ((Elf_Addr**)tls)[0]; 2774 dtvsize = dtv[1]; 2775 tlsstart = (Elf_Addr) tls; 2776 tlsend = tlsstart + size; 2777 for (i = 0; i < dtvsize; i++) { 2778 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 2779 free((void*) dtv[i+2]); 2780 } 2781 } 2782 2783 free((void*) tlsstart); 2784 } 2785 2786 #endif 2787 2788 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 2789 defined(__arm__) 2790 2791 /* 2792 * Allocate Static TLS using the Variant II method. 2793 */ 2794 void * 2795 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 2796 { 2797 Obj_Entry *obj; 2798 size_t size; 2799 char *tls; 2800 Elf_Addr *dtv, *olddtv; 2801 Elf_Addr segbase, oldsegbase, addr; 2802 int i; 2803 2804 size = round(tls_static_space, tcbalign); 2805 2806 assert(tcbsize >= 2*sizeof(Elf_Addr)); 2807 tls = malloc(size + tcbsize); 2808 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 2809 2810 segbase = (Elf_Addr)(tls + size); 2811 ((Elf_Addr*)segbase)[0] = segbase; 2812 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 2813 2814 dtv[0] = tls_dtv_generation; 2815 dtv[1] = tls_max_index; 2816 2817 if (oldtls) { 2818 /* 2819 * Copy the static TLS block over whole. 2820 */ 2821 oldsegbase = (Elf_Addr) oldtls; 2822 memcpy((void *)(segbase - tls_static_space), 2823 (const void *)(oldsegbase - tls_static_space), 2824 tls_static_space); 2825 2826 /* 2827 * If any dynamic TLS blocks have been created tls_get_addr(), 2828 * move them over. 2829 */ 2830 olddtv = ((Elf_Addr**)oldsegbase)[1]; 2831 for (i = 0; i < olddtv[1]; i++) { 2832 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 2833 dtv[i+2] = olddtv[i+2]; 2834 olddtv[i+2] = 0; 2835 } 2836 } 2837 2838 /* 2839 * We assume that this block was the one we created with 2840 * allocate_initial_tls(). 2841 */ 2842 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 2843 } else { 2844 for (obj = objs; obj; obj = obj->next) { 2845 if (obj->tlsoffset) { 2846 addr = segbase - obj->tlsoffset; 2847 memset((void*) (addr + obj->tlsinitsize), 2848 0, obj->tlssize - obj->tlsinitsize); 2849 if (obj->tlsinit) 2850 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 2851 dtv[obj->tlsindex + 1] = addr; 2852 } 2853 } 2854 } 2855 2856 return (void*) segbase; 2857 } 2858 2859 void 2860 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 2861 { 2862 size_t size; 2863 Elf_Addr* dtv; 2864 int dtvsize, i; 2865 Elf_Addr tlsstart, tlsend; 2866 2867 /* 2868 * Figure out the size of the initial TLS block so that we can 2869 * find stuff which ___tls_get_addr() allocated dynamically. 2870 */ 2871 size = round(tls_static_space, tcbalign); 2872 2873 dtv = ((Elf_Addr**)tls)[1]; 2874 dtvsize = dtv[1]; 2875 tlsend = (Elf_Addr) tls; 2876 tlsstart = tlsend - size; 2877 for (i = 0; i < dtvsize; i++) { 2878 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 2879 free((void*) dtv[i+2]); 2880 } 2881 } 2882 2883 free((void*) tlsstart); 2884 } 2885 2886 #endif 2887 2888 /* 2889 * Allocate TLS block for module with given index. 2890 */ 2891 void * 2892 allocate_module_tls(int index) 2893 { 2894 Obj_Entry* obj; 2895 char* p; 2896 2897 for (obj = obj_list; obj; obj = obj->next) { 2898 if (obj->tlsindex == index) 2899 break; 2900 } 2901 if (!obj) { 2902 _rtld_error("Can't find module with TLS index %d", index); 2903 die(); 2904 } 2905 2906 p = malloc(obj->tlssize); 2907 memcpy(p, obj->tlsinit, obj->tlsinitsize); 2908 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 2909 2910 return p; 2911 } 2912 2913 bool 2914 allocate_tls_offset(Obj_Entry *obj) 2915 { 2916 size_t off; 2917 2918 if (obj->tls_done) 2919 return true; 2920 2921 if (obj->tlssize == 0) { 2922 obj->tls_done = true; 2923 return true; 2924 } 2925 2926 if (obj->tlsindex == 1) 2927 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 2928 else 2929 off = calculate_tls_offset(tls_last_offset, tls_last_size, 2930 obj->tlssize, obj->tlsalign); 2931 2932 /* 2933 * If we have already fixed the size of the static TLS block, we 2934 * must stay within that size. When allocating the static TLS, we 2935 * leave a small amount of space spare to be used for dynamically 2936 * loading modules which use static TLS. 2937 */ 2938 if (tls_static_space) { 2939 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 2940 return false; 2941 } 2942 2943 tls_last_offset = obj->tlsoffset = off; 2944 tls_last_size = obj->tlssize; 2945 obj->tls_done = true; 2946 2947 return true; 2948 } 2949 2950 void 2951 free_tls_offset(Obj_Entry *obj) 2952 { 2953 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 2954 defined(__arm__) 2955 /* 2956 * If we were the last thing to allocate out of the static TLS 2957 * block, we give our space back to the 'allocator'. This is a 2958 * simplistic workaround to allow libGL.so.1 to be loaded and 2959 * unloaded multiple times. We only handle the Variant II 2960 * mechanism for now - this really needs a proper allocator. 2961 */ 2962 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 2963 == calculate_tls_end(tls_last_offset, tls_last_size)) { 2964 tls_last_offset -= obj->tlssize; 2965 tls_last_size = 0; 2966 } 2967 #endif 2968 } 2969 2970 void * 2971 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 2972 { 2973 void *ret; 2974 int lockstate; 2975 2976 lockstate = wlock_acquire(rtld_bind_lock); 2977 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 2978 wlock_release(rtld_bind_lock, lockstate); 2979 return (ret); 2980 } 2981 2982 void 2983 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 2984 { 2985 int lockstate; 2986 2987 lockstate = wlock_acquire(rtld_bind_lock); 2988 free_tls(tcb, tcbsize, tcbalign); 2989 wlock_release(rtld_bind_lock, lockstate); 2990 } 2991 2992 static void 2993 object_add_name(Obj_Entry *obj, const char *name) 2994 { 2995 Name_Entry *entry; 2996 size_t len; 2997 2998 len = strlen(name); 2999 entry = malloc(sizeof(Name_Entry) + len); 3000 3001 if (entry != NULL) { 3002 strcpy(entry->name, name); 3003 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3004 } 3005 } 3006 3007 static int 3008 object_match_name(const Obj_Entry *obj, const char *name) 3009 { 3010 Name_Entry *entry; 3011 3012 STAILQ_FOREACH(entry, &obj->names, link) { 3013 if (strcmp(name, entry->name) == 0) 3014 return (1); 3015 } 3016 return (0); 3017 } 3018 3019 static Obj_Entry * 3020 locate_dependency(const Obj_Entry *obj, const char *name) 3021 { 3022 const Objlist_Entry *entry; 3023 const Needed_Entry *needed; 3024 3025 STAILQ_FOREACH(entry, &list_main, link) { 3026 if (object_match_name(entry->obj, name)) 3027 return entry->obj; 3028 } 3029 3030 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3031 if (needed->obj == NULL) 3032 continue; 3033 if (object_match_name(needed->obj, name)) 3034 return needed->obj; 3035 } 3036 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3037 obj->path, name); 3038 die(); 3039 } 3040 3041 static int 3042 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3043 const Elf_Vernaux *vna) 3044 { 3045 const Elf_Verdef *vd; 3046 const char *vername; 3047 3048 vername = refobj->strtab + vna->vna_name; 3049 vd = depobj->verdef; 3050 if (vd == NULL) { 3051 _rtld_error("%s: version %s required by %s not defined", 3052 depobj->path, vername, refobj->path); 3053 return (-1); 3054 } 3055 for (;;) { 3056 if (vd->vd_version != VER_DEF_CURRENT) { 3057 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3058 depobj->path, vd->vd_version); 3059 return (-1); 3060 } 3061 if (vna->vna_hash == vd->vd_hash) { 3062 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3063 ((char *)vd + vd->vd_aux); 3064 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3065 return (0); 3066 } 3067 if (vd->vd_next == 0) 3068 break; 3069 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3070 } 3071 if (vna->vna_flags & VER_FLG_WEAK) 3072 return (0); 3073 _rtld_error("%s: version %s required by %s not found", 3074 depobj->path, vername, refobj->path); 3075 return (-1); 3076 } 3077 3078 static int 3079 rtld_verify_object_versions(Obj_Entry *obj) 3080 { 3081 const Elf_Verneed *vn; 3082 const Elf_Verdef *vd; 3083 const Elf_Verdaux *vda; 3084 const Elf_Vernaux *vna; 3085 const Obj_Entry *depobj; 3086 int maxvernum, vernum; 3087 3088 maxvernum = 0; 3089 /* 3090 * Walk over defined and required version records and figure out 3091 * max index used by any of them. Do very basic sanity checking 3092 * while there. 3093 */ 3094 vn = obj->verneed; 3095 while (vn != NULL) { 3096 if (vn->vn_version != VER_NEED_CURRENT) { 3097 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3098 obj->path, vn->vn_version); 3099 return (-1); 3100 } 3101 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3102 for (;;) { 3103 vernum = VER_NEED_IDX(vna->vna_other); 3104 if (vernum > maxvernum) 3105 maxvernum = vernum; 3106 if (vna->vna_next == 0) 3107 break; 3108 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3109 } 3110 if (vn->vn_next == 0) 3111 break; 3112 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3113 } 3114 3115 vd = obj->verdef; 3116 while (vd != NULL) { 3117 if (vd->vd_version != VER_DEF_CURRENT) { 3118 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3119 obj->path, vd->vd_version); 3120 return (-1); 3121 } 3122 vernum = VER_DEF_IDX(vd->vd_ndx); 3123 if (vernum > maxvernum) 3124 maxvernum = vernum; 3125 if (vd->vd_next == 0) 3126 break; 3127 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3128 } 3129 3130 if (maxvernum == 0) 3131 return (0); 3132 3133 /* 3134 * Store version information in array indexable by version index. 3135 * Verify that object version requirements are satisfied along the 3136 * way. 3137 */ 3138 obj->vernum = maxvernum + 1; 3139 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3140 3141 vd = obj->verdef; 3142 while (vd != NULL) { 3143 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3144 vernum = VER_DEF_IDX(vd->vd_ndx); 3145 assert(vernum <= maxvernum); 3146 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3147 obj->vertab[vernum].hash = vd->vd_hash; 3148 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3149 obj->vertab[vernum].file = NULL; 3150 obj->vertab[vernum].flags = 0; 3151 } 3152 if (vd->vd_next == 0) 3153 break; 3154 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3155 } 3156 3157 vn = obj->verneed; 3158 while (vn != NULL) { 3159 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3160 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3161 for (;;) { 3162 if (check_object_provided_version(obj, depobj, vna)) 3163 return (-1); 3164 vernum = VER_NEED_IDX(vna->vna_other); 3165 assert(vernum <= maxvernum); 3166 obj->vertab[vernum].hash = vna->vna_hash; 3167 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3168 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3169 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3170 VER_INFO_HIDDEN : 0; 3171 if (vna->vna_next == 0) 3172 break; 3173 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3174 } 3175 if (vn->vn_next == 0) 3176 break; 3177 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3178 } 3179 return 0; 3180 } 3181 3182 static int 3183 rtld_verify_versions(const Objlist *objlist) 3184 { 3185 Objlist_Entry *entry; 3186 int rc; 3187 3188 rc = 0; 3189 STAILQ_FOREACH(entry, objlist, link) { 3190 /* 3191 * Skip dummy objects or objects that have their version requirements 3192 * already checked. 3193 */ 3194 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3195 continue; 3196 if (rtld_verify_object_versions(entry->obj) == -1) { 3197 rc = -1; 3198 if (ld_tracing == NULL) 3199 break; 3200 } 3201 } 3202 return rc; 3203 } 3204 3205 const Ver_Entry * 3206 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3207 { 3208 Elf_Versym vernum; 3209 3210 if (obj->vertab) { 3211 vernum = VER_NDX(obj->versyms[symnum]); 3212 if (vernum >= obj->vernum) { 3213 _rtld_error("%s: symbol %s has wrong verneed value %d", 3214 obj->path, obj->strtab + symnum, vernum); 3215 } else if (obj->vertab[vernum].hash != 0) { 3216 return &obj->vertab[vernum]; 3217 } 3218 } 3219 return NULL; 3220 } 3221