1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/sysctl.h> 44 #include <sys/uio.h> 45 #include <sys/utsname.h> 46 #include <sys/ktrace.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 #include "libmap.h" 61 #include "rtld_tls.h" 62 63 #ifndef COMPAT_32BIT 64 #define PATH_RTLD "/libexec/ld-elf.so.1" 65 #else 66 #define PATH_RTLD "/libexec/ld-elf32.so.1" 67 #endif 68 69 /* Types. */ 70 typedef void (*func_ptr_type)(); 71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73 /* 74 * This structure provides a reentrant way to keep a list of objects and 75 * check which ones have already been processed in some way. 76 */ 77 typedef struct Struct_DoneList { 78 const Obj_Entry **objs; /* Array of object pointers */ 79 unsigned int num_alloc; /* Allocated size of the array */ 80 unsigned int num_used; /* Number of array slots used */ 81 } DoneList; 82 83 /* 84 * Function declarations. 85 */ 86 static const char *basename(const char *); 87 static void die(void) __dead2; 88 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 89 const Elf_Dyn **); 90 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 91 static void digest_dynamic(Obj_Entry *, int); 92 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 93 static Obj_Entry *dlcheck(void *); 94 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 95 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 96 static bool donelist_check(DoneList *, const Obj_Entry *); 97 static void errmsg_restore(char *); 98 static char *errmsg_save(void); 99 static void *fill_search_info(const char *, size_t, void *); 100 static char *find_library(const char *, const Obj_Entry *); 101 static const char *gethints(void); 102 static void init_dag(Obj_Entry *); 103 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 104 static void init_rtld(caddr_t, Elf_Auxinfo **); 105 static void initlist_add_neededs(Needed_Entry *, Objlist *); 106 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 107 static bool is_exported(const Elf_Sym *); 108 static void linkmap_add(Obj_Entry *); 109 static void linkmap_delete(Obj_Entry *); 110 static int load_needed_objects(Obj_Entry *, int); 111 static int load_preload_objects(void); 112 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 113 static Obj_Entry *obj_from_addr(const void *); 114 static void objlist_call_fini(Objlist *, bool, int *); 115 static void objlist_call_init(Objlist *, int *); 116 static void objlist_clear(Objlist *); 117 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 118 static void objlist_init(Objlist *); 119 static void objlist_push_head(Objlist *, Obj_Entry *); 120 static void objlist_push_tail(Objlist *, Obj_Entry *); 121 static void objlist_remove(Objlist *, Obj_Entry *); 122 static void *path_enumerate(const char *, path_enum_proc, void *); 123 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 124 static int rtld_dirname(const char *, char *); 125 static int rtld_dirname_abs(const char *, char *); 126 static void rtld_exit(void); 127 static char *search_library_path(const char *, const char *); 128 static const void **get_program_var_addr(const char *); 129 static void set_program_var(const char *, const void *); 130 static const Elf_Sym *symlook_default(const char *, unsigned long, 131 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 132 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 133 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 134 static const Elf_Sym *symlook_needed(const char *, unsigned long, 135 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 136 int, DoneList *); 137 static void trace_loaded_objects(Obj_Entry *); 138 static void unlink_object(Obj_Entry *); 139 static void unload_object(Obj_Entry *); 140 static void unref_dag(Obj_Entry *); 141 static void ref_dag(Obj_Entry *); 142 static int origin_subst_one(char **, const char *, const char *, 143 const char *, char *); 144 static char *origin_subst(const char *, const char *); 145 static int rtld_verify_versions(const Objlist *); 146 static int rtld_verify_object_versions(Obj_Entry *); 147 static void object_add_name(Obj_Entry *, const char *); 148 static int object_match_name(const Obj_Entry *, const char *); 149 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 150 151 void r_debug_state(struct r_debug *, struct link_map *); 152 153 /* 154 * Data declarations. 155 */ 156 static char *error_message; /* Message for dlerror(), or NULL */ 157 struct r_debug r_debug; /* for GDB; */ 158 static bool libmap_disable; /* Disable libmap */ 159 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 160 static bool trust; /* False for setuid and setgid programs */ 161 static bool dangerous_ld_env; /* True if environment variables have been 162 used to affect the libraries loaded */ 163 static char *ld_bind_now; /* Environment variable for immediate binding */ 164 static char *ld_debug; /* Environment variable for debugging */ 165 static char *ld_library_path; /* Environment variable for search path */ 166 static char *ld_preload; /* Environment variable for libraries to 167 load first */ 168 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 169 static char *ld_tracing; /* Called from ldd to print libs */ 170 static char *ld_utrace; /* Use utrace() to log events. */ 171 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 172 static Obj_Entry **obj_tail; /* Link field of last object in list */ 173 static Obj_Entry *obj_main; /* The main program shared object */ 174 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 175 static unsigned int obj_count; /* Number of objects in obj_list */ 176 static unsigned int obj_loads; /* Number of objects in obj_list */ 177 178 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 179 STAILQ_HEAD_INITIALIZER(list_global); 180 static Objlist list_main = /* Objects loaded at program startup */ 181 STAILQ_HEAD_INITIALIZER(list_main); 182 static Objlist list_fini = /* Objects needing fini() calls */ 183 STAILQ_HEAD_INITIALIZER(list_fini); 184 185 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 186 187 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 188 189 extern Elf_Dyn _DYNAMIC; 190 #pragma weak _DYNAMIC 191 #ifndef RTLD_IS_DYNAMIC 192 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 193 #endif 194 195 int osreldate, pagesize; 196 197 /* 198 * These are the functions the dynamic linker exports to application 199 * programs. They are the only symbols the dynamic linker is willing 200 * to export from itself. 201 */ 202 static func_ptr_type exports[] = { 203 (func_ptr_type) &_rtld_error, 204 (func_ptr_type) &dlclose, 205 (func_ptr_type) &dlerror, 206 (func_ptr_type) &dlopen, 207 (func_ptr_type) &dlsym, 208 (func_ptr_type) &dlfunc, 209 (func_ptr_type) &dlvsym, 210 (func_ptr_type) &dladdr, 211 (func_ptr_type) &dllockinit, 212 (func_ptr_type) &dlinfo, 213 (func_ptr_type) &_rtld_thread_init, 214 #ifdef __i386__ 215 (func_ptr_type) &___tls_get_addr, 216 #endif 217 (func_ptr_type) &__tls_get_addr, 218 (func_ptr_type) &_rtld_allocate_tls, 219 (func_ptr_type) &_rtld_free_tls, 220 (func_ptr_type) &dl_iterate_phdr, 221 (func_ptr_type) &_rtld_atfork_pre, 222 (func_ptr_type) &_rtld_atfork_post, 223 NULL 224 }; 225 226 /* 227 * Global declarations normally provided by crt1. The dynamic linker is 228 * not built with crt1, so we have to provide them ourselves. 229 */ 230 char *__progname; 231 char **environ; 232 233 /* 234 * Globals to control TLS allocation. 235 */ 236 size_t tls_last_offset; /* Static TLS offset of last module */ 237 size_t tls_last_size; /* Static TLS size of last module */ 238 size_t tls_static_space; /* Static TLS space allocated */ 239 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 240 int tls_max_index = 1; /* Largest module index allocated */ 241 242 /* 243 * Fill in a DoneList with an allocation large enough to hold all of 244 * the currently-loaded objects. Keep this as a macro since it calls 245 * alloca and we want that to occur within the scope of the caller. 246 */ 247 #define donelist_init(dlp) \ 248 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 249 assert((dlp)->objs != NULL), \ 250 (dlp)->num_alloc = obj_count, \ 251 (dlp)->num_used = 0) 252 253 #define UTRACE_DLOPEN_START 1 254 #define UTRACE_DLOPEN_STOP 2 255 #define UTRACE_DLCLOSE_START 3 256 #define UTRACE_DLCLOSE_STOP 4 257 #define UTRACE_LOAD_OBJECT 5 258 #define UTRACE_UNLOAD_OBJECT 6 259 #define UTRACE_ADD_RUNDEP 7 260 #define UTRACE_PRELOAD_FINISHED 8 261 #define UTRACE_INIT_CALL 9 262 #define UTRACE_FINI_CALL 10 263 264 struct utrace_rtld { 265 char sig[4]; /* 'RTLD' */ 266 int event; 267 void *handle; 268 void *mapbase; /* Used for 'parent' and 'init/fini' */ 269 size_t mapsize; 270 int refcnt; /* Used for 'mode' */ 271 char name[MAXPATHLEN]; 272 }; 273 274 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 275 if (ld_utrace != NULL) \ 276 ld_utrace_log(e, h, mb, ms, r, n); \ 277 } while (0) 278 279 static void 280 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 281 int refcnt, const char *name) 282 { 283 struct utrace_rtld ut; 284 285 ut.sig[0] = 'R'; 286 ut.sig[1] = 'T'; 287 ut.sig[2] = 'L'; 288 ut.sig[3] = 'D'; 289 ut.event = event; 290 ut.handle = handle; 291 ut.mapbase = mapbase; 292 ut.mapsize = mapsize; 293 ut.refcnt = refcnt; 294 bzero(ut.name, sizeof(ut.name)); 295 if (name) 296 strlcpy(ut.name, name, sizeof(ut.name)); 297 utrace(&ut, sizeof(ut)); 298 } 299 300 /* 301 * Main entry point for dynamic linking. The first argument is the 302 * stack pointer. The stack is expected to be laid out as described 303 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 304 * Specifically, the stack pointer points to a word containing 305 * ARGC. Following that in the stack is a null-terminated sequence 306 * of pointers to argument strings. Then comes a null-terminated 307 * sequence of pointers to environment strings. Finally, there is a 308 * sequence of "auxiliary vector" entries. 309 * 310 * The second argument points to a place to store the dynamic linker's 311 * exit procedure pointer and the third to a place to store the main 312 * program's object. 313 * 314 * The return value is the main program's entry point. 315 */ 316 func_ptr_type 317 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 318 { 319 Elf_Auxinfo *aux_info[AT_COUNT]; 320 int i; 321 int argc; 322 char **argv; 323 char **env; 324 Elf_Auxinfo *aux; 325 Elf_Auxinfo *auxp; 326 const char *argv0; 327 Objlist_Entry *entry; 328 Obj_Entry *obj; 329 Obj_Entry **preload_tail; 330 Objlist initlist; 331 int lockstate; 332 333 /* 334 * On entry, the dynamic linker itself has not been relocated yet. 335 * Be very careful not to reference any global data until after 336 * init_rtld has returned. It is OK to reference file-scope statics 337 * and string constants, and to call static and global functions. 338 */ 339 340 /* Find the auxiliary vector on the stack. */ 341 argc = *sp++; 342 argv = (char **) sp; 343 sp += argc + 1; /* Skip over arguments and NULL terminator */ 344 env = (char **) sp; 345 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 346 ; 347 aux = (Elf_Auxinfo *) sp; 348 349 /* Digest the auxiliary vector. */ 350 for (i = 0; i < AT_COUNT; i++) 351 aux_info[i] = NULL; 352 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 353 if (auxp->a_type < AT_COUNT) 354 aux_info[auxp->a_type] = auxp; 355 } 356 357 /* Initialize and relocate ourselves. */ 358 assert(aux_info[AT_BASE] != NULL); 359 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 360 361 __progname = obj_rtld.path; 362 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 363 environ = env; 364 365 trust = !issetugid(); 366 367 ld_bind_now = getenv(LD_ "BIND_NOW"); 368 /* 369 * If the process is tainted, then we un-set the dangerous environment 370 * variables. The process will be marked as tainted until setuid(2) 371 * is called. If any child process calls setuid(2) we do not want any 372 * future processes to honor the potentially un-safe variables. 373 */ 374 if (!trust) { 375 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 376 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 377 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH")) { 378 _rtld_error("environment corrupt; aborting"); 379 die(); 380 } 381 } 382 ld_debug = getenv(LD_ "DEBUG"); 383 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 384 libmap_override = getenv(LD_ "LIBMAP"); 385 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 386 ld_preload = getenv(LD_ "PRELOAD"); 387 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 388 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 389 (ld_library_path != NULL) || (ld_preload != NULL) || 390 (ld_elf_hints_path != NULL); 391 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 392 ld_utrace = getenv(LD_ "UTRACE"); 393 394 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 395 ld_elf_hints_path = _PATH_ELF_HINTS; 396 397 if (ld_debug != NULL && *ld_debug != '\0') 398 debug = 1; 399 dbg("%s is initialized, base address = %p", __progname, 400 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 401 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 402 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 403 404 /* 405 * Load the main program, or process its program header if it is 406 * already loaded. 407 */ 408 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 409 int fd = aux_info[AT_EXECFD]->a_un.a_val; 410 dbg("loading main program"); 411 obj_main = map_object(fd, argv0, NULL); 412 close(fd); 413 if (obj_main == NULL) 414 die(); 415 } else { /* Main program already loaded. */ 416 const Elf_Phdr *phdr; 417 int phnum; 418 caddr_t entry; 419 420 dbg("processing main program's program header"); 421 assert(aux_info[AT_PHDR] != NULL); 422 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 423 assert(aux_info[AT_PHNUM] != NULL); 424 phnum = aux_info[AT_PHNUM]->a_un.a_val; 425 assert(aux_info[AT_PHENT] != NULL); 426 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 427 assert(aux_info[AT_ENTRY] != NULL); 428 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 429 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 430 die(); 431 } 432 433 if (aux_info[AT_EXECPATH] != 0) { 434 char *kexecpath; 435 char buf[MAXPATHLEN]; 436 437 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 438 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 439 if (kexecpath[0] == '/') 440 obj_main->path = kexecpath; 441 else if (getcwd(buf, sizeof(buf)) == NULL || 442 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 443 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 444 obj_main->path = xstrdup(argv0); 445 else 446 obj_main->path = xstrdup(buf); 447 } else { 448 dbg("No AT_EXECPATH"); 449 obj_main->path = xstrdup(argv0); 450 } 451 dbg("obj_main path %s", obj_main->path); 452 obj_main->mainprog = true; 453 454 /* 455 * Get the actual dynamic linker pathname from the executable if 456 * possible. (It should always be possible.) That ensures that 457 * gdb will find the right dynamic linker even if a non-standard 458 * one is being used. 459 */ 460 if (obj_main->interp != NULL && 461 strcmp(obj_main->interp, obj_rtld.path) != 0) { 462 free(obj_rtld.path); 463 obj_rtld.path = xstrdup(obj_main->interp); 464 __progname = obj_rtld.path; 465 } 466 467 digest_dynamic(obj_main, 0); 468 469 linkmap_add(obj_main); 470 linkmap_add(&obj_rtld); 471 472 /* Link the main program into the list of objects. */ 473 *obj_tail = obj_main; 474 obj_tail = &obj_main->next; 475 obj_count++; 476 obj_loads++; 477 /* Make sure we don't call the main program's init and fini functions. */ 478 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 479 480 /* Initialize a fake symbol for resolving undefined weak references. */ 481 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 482 sym_zero.st_shndx = SHN_UNDEF; 483 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 484 485 if (!libmap_disable) 486 libmap_disable = (bool)lm_init(libmap_override); 487 488 dbg("loading LD_PRELOAD libraries"); 489 if (load_preload_objects() == -1) 490 die(); 491 preload_tail = obj_tail; 492 493 dbg("loading needed objects"); 494 if (load_needed_objects(obj_main, 0) == -1) 495 die(); 496 497 /* Make a list of all objects loaded at startup. */ 498 for (obj = obj_list; obj != NULL; obj = obj->next) { 499 objlist_push_tail(&list_main, obj); 500 obj->refcount++; 501 } 502 503 dbg("checking for required versions"); 504 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 505 die(); 506 507 if (ld_tracing) { /* We're done */ 508 trace_loaded_objects(obj_main); 509 exit(0); 510 } 511 512 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 513 dump_relocations(obj_main); 514 exit (0); 515 } 516 517 /* setup TLS for main thread */ 518 dbg("initializing initial thread local storage"); 519 STAILQ_FOREACH(entry, &list_main, link) { 520 /* 521 * Allocate all the initial objects out of the static TLS 522 * block even if they didn't ask for it. 523 */ 524 allocate_tls_offset(entry->obj); 525 } 526 allocate_initial_tls(obj_list); 527 528 if (relocate_objects(obj_main, 529 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 530 die(); 531 532 dbg("doing copy relocations"); 533 if (do_copy_relocations(obj_main) == -1) 534 die(); 535 536 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 537 dump_relocations(obj_main); 538 exit (0); 539 } 540 541 dbg("initializing key program variables"); 542 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 543 set_program_var("environ", env); 544 set_program_var("__elf_aux_vector", aux); 545 546 dbg("initializing thread locks"); 547 lockdflt_init(); 548 549 /* Make a list of init functions to call. */ 550 objlist_init(&initlist); 551 initlist_add_objects(obj_list, preload_tail, &initlist); 552 553 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 554 555 lockstate = wlock_acquire(rtld_bind_lock); 556 objlist_call_init(&initlist, &lockstate); 557 objlist_clear(&initlist); 558 wlock_release(rtld_bind_lock, lockstate); 559 560 dbg("transferring control to program entry point = %p", obj_main->entry); 561 562 /* Return the exit procedure and the program entry point. */ 563 *exit_proc = rtld_exit; 564 *objp = obj_main; 565 return (func_ptr_type) obj_main->entry; 566 } 567 568 Elf_Addr 569 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 570 { 571 const Elf_Rel *rel; 572 const Elf_Sym *def; 573 const Obj_Entry *defobj; 574 Elf_Addr *where; 575 Elf_Addr target; 576 int lockstate; 577 578 lockstate = rlock_acquire(rtld_bind_lock); 579 if (obj->pltrel) 580 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 581 else 582 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 583 584 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 585 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 586 if (def == NULL) 587 die(); 588 589 target = (Elf_Addr)(defobj->relocbase + def->st_value); 590 591 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 592 defobj->strtab + def->st_name, basename(obj->path), 593 (void *)target, basename(defobj->path)); 594 595 /* 596 * Write the new contents for the jmpslot. Note that depending on 597 * architecture, the value which we need to return back to the 598 * lazy binding trampoline may or may not be the target 599 * address. The value returned from reloc_jmpslot() is the value 600 * that the trampoline needs. 601 */ 602 target = reloc_jmpslot(where, target, defobj, obj, rel); 603 rlock_release(rtld_bind_lock, lockstate); 604 return target; 605 } 606 607 /* 608 * Error reporting function. Use it like printf. If formats the message 609 * into a buffer, and sets things up so that the next call to dlerror() 610 * will return the message. 611 */ 612 void 613 _rtld_error(const char *fmt, ...) 614 { 615 static char buf[512]; 616 va_list ap; 617 618 va_start(ap, fmt); 619 vsnprintf(buf, sizeof buf, fmt, ap); 620 error_message = buf; 621 va_end(ap); 622 } 623 624 /* 625 * Return a dynamically-allocated copy of the current error message, if any. 626 */ 627 static char * 628 errmsg_save(void) 629 { 630 return error_message == NULL ? NULL : xstrdup(error_message); 631 } 632 633 /* 634 * Restore the current error message from a copy which was previously saved 635 * by errmsg_save(). The copy is freed. 636 */ 637 static void 638 errmsg_restore(char *saved_msg) 639 { 640 if (saved_msg == NULL) 641 error_message = NULL; 642 else { 643 _rtld_error("%s", saved_msg); 644 free(saved_msg); 645 } 646 } 647 648 static const char * 649 basename(const char *name) 650 { 651 const char *p = strrchr(name, '/'); 652 return p != NULL ? p + 1 : name; 653 } 654 655 static struct utsname uts; 656 657 static int 658 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 659 char *may_free) 660 { 661 const char *p, *p1; 662 char *res1; 663 int subst_len; 664 int kw_len; 665 666 res1 = *res = NULL; 667 p = real; 668 subst_len = kw_len = 0; 669 for (;;) { 670 p1 = strstr(p, kw); 671 if (p1 != NULL) { 672 if (subst_len == 0) { 673 subst_len = strlen(subst); 674 kw_len = strlen(kw); 675 } 676 if (*res == NULL) { 677 *res = xmalloc(PATH_MAX); 678 res1 = *res; 679 } 680 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 681 _rtld_error("Substitution of %s in %s cannot be performed", 682 kw, real); 683 if (may_free != NULL) 684 free(may_free); 685 free(res); 686 return (false); 687 } 688 memcpy(res1, p, p1 - p); 689 res1 += p1 - p; 690 memcpy(res1, subst, subst_len); 691 res1 += subst_len; 692 p = p1 + kw_len; 693 } else { 694 if (*res == NULL) { 695 if (may_free != NULL) 696 *res = may_free; 697 else 698 *res = xstrdup(real); 699 return (true); 700 } 701 *res1 = '\0'; 702 if (may_free != NULL) 703 free(may_free); 704 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 705 free(res); 706 return (false); 707 } 708 return (true); 709 } 710 } 711 } 712 713 static char * 714 origin_subst(const char *real, const char *origin_path) 715 { 716 char *res1, *res2, *res3, *res4; 717 718 if (uts.sysname[0] == '\0') { 719 if (uname(&uts) != 0) { 720 _rtld_error("utsname failed: %d", errno); 721 return (NULL); 722 } 723 } 724 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 725 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 726 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 727 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 728 return (NULL); 729 return (res4); 730 } 731 732 static void 733 die(void) 734 { 735 const char *msg = dlerror(); 736 737 if (msg == NULL) 738 msg = "Fatal error"; 739 errx(1, "%s", msg); 740 } 741 742 /* 743 * Process a shared object's DYNAMIC section, and save the important 744 * information in its Obj_Entry structure. 745 */ 746 static void 747 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 748 const Elf_Dyn **dyn_soname) 749 { 750 const Elf_Dyn *dynp; 751 Needed_Entry **needed_tail = &obj->needed; 752 int plttype = DT_REL; 753 754 *dyn_rpath = NULL; 755 *dyn_soname = NULL; 756 757 obj->bind_now = false; 758 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 759 switch (dynp->d_tag) { 760 761 case DT_REL: 762 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 763 break; 764 765 case DT_RELSZ: 766 obj->relsize = dynp->d_un.d_val; 767 break; 768 769 case DT_RELENT: 770 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 771 break; 772 773 case DT_JMPREL: 774 obj->pltrel = (const Elf_Rel *) 775 (obj->relocbase + dynp->d_un.d_ptr); 776 break; 777 778 case DT_PLTRELSZ: 779 obj->pltrelsize = dynp->d_un.d_val; 780 break; 781 782 case DT_RELA: 783 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 784 break; 785 786 case DT_RELASZ: 787 obj->relasize = dynp->d_un.d_val; 788 break; 789 790 case DT_RELAENT: 791 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 792 break; 793 794 case DT_PLTREL: 795 plttype = dynp->d_un.d_val; 796 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 797 break; 798 799 case DT_SYMTAB: 800 obj->symtab = (const Elf_Sym *) 801 (obj->relocbase + dynp->d_un.d_ptr); 802 break; 803 804 case DT_SYMENT: 805 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 806 break; 807 808 case DT_STRTAB: 809 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 810 break; 811 812 case DT_STRSZ: 813 obj->strsize = dynp->d_un.d_val; 814 break; 815 816 case DT_VERNEED: 817 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 818 dynp->d_un.d_val); 819 break; 820 821 case DT_VERNEEDNUM: 822 obj->verneednum = dynp->d_un.d_val; 823 break; 824 825 case DT_VERDEF: 826 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 827 dynp->d_un.d_val); 828 break; 829 830 case DT_VERDEFNUM: 831 obj->verdefnum = dynp->d_un.d_val; 832 break; 833 834 case DT_VERSYM: 835 obj->versyms = (const Elf_Versym *)(obj->relocbase + 836 dynp->d_un.d_val); 837 break; 838 839 case DT_HASH: 840 { 841 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 842 (obj->relocbase + dynp->d_un.d_ptr); 843 obj->nbuckets = hashtab[0]; 844 obj->nchains = hashtab[1]; 845 obj->buckets = hashtab + 2; 846 obj->chains = obj->buckets + obj->nbuckets; 847 } 848 break; 849 850 case DT_NEEDED: 851 if (!obj->rtld) { 852 Needed_Entry *nep = NEW(Needed_Entry); 853 nep->name = dynp->d_un.d_val; 854 nep->obj = NULL; 855 nep->next = NULL; 856 857 *needed_tail = nep; 858 needed_tail = &nep->next; 859 } 860 break; 861 862 case DT_PLTGOT: 863 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 864 break; 865 866 case DT_TEXTREL: 867 obj->textrel = true; 868 break; 869 870 case DT_SYMBOLIC: 871 obj->symbolic = true; 872 break; 873 874 case DT_RPATH: 875 case DT_RUNPATH: /* XXX: process separately */ 876 /* 877 * We have to wait until later to process this, because we 878 * might not have gotten the address of the string table yet. 879 */ 880 *dyn_rpath = dynp; 881 break; 882 883 case DT_SONAME: 884 *dyn_soname = dynp; 885 break; 886 887 case DT_INIT: 888 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 889 break; 890 891 case DT_FINI: 892 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 893 break; 894 895 /* 896 * Don't process DT_DEBUG on MIPS as the dynamic section 897 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 898 */ 899 900 #ifndef __mips__ 901 case DT_DEBUG: 902 /* XXX - not implemented yet */ 903 if (!early) 904 dbg("Filling in DT_DEBUG entry"); 905 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 906 break; 907 #endif 908 909 case DT_FLAGS: 910 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 911 obj->z_origin = true; 912 if (dynp->d_un.d_val & DF_SYMBOLIC) 913 obj->symbolic = true; 914 if (dynp->d_un.d_val & DF_TEXTREL) 915 obj->textrel = true; 916 if (dynp->d_un.d_val & DF_BIND_NOW) 917 obj->bind_now = true; 918 if (dynp->d_un.d_val & DF_STATIC_TLS) 919 ; 920 break; 921 #ifdef __mips__ 922 case DT_MIPS_LOCAL_GOTNO: 923 obj->local_gotno = dynp->d_un.d_val; 924 break; 925 926 case DT_MIPS_SYMTABNO: 927 obj->symtabno = dynp->d_un.d_val; 928 break; 929 930 case DT_MIPS_GOTSYM: 931 obj->gotsym = dynp->d_un.d_val; 932 break; 933 934 case DT_MIPS_RLD_MAP: 935 #ifdef notyet 936 if (!early) 937 dbg("Filling in DT_DEBUG entry"); 938 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 939 #endif 940 break; 941 #endif 942 943 case DT_FLAGS_1: 944 if (dynp->d_un.d_val & DF_1_NOOPEN) 945 obj->z_noopen = true; 946 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 947 obj->z_origin = true; 948 if (dynp->d_un.d_val & DF_1_GLOBAL) 949 /* XXX */; 950 if (dynp->d_un.d_val & DF_1_BIND_NOW) 951 obj->bind_now = true; 952 if (dynp->d_un.d_val & DF_1_NODELETE) 953 obj->z_nodelete = true; 954 break; 955 956 default: 957 if (!early) { 958 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 959 (long)dynp->d_tag); 960 } 961 break; 962 } 963 } 964 965 obj->traced = false; 966 967 if (plttype == DT_RELA) { 968 obj->pltrela = (const Elf_Rela *) obj->pltrel; 969 obj->pltrel = NULL; 970 obj->pltrelasize = obj->pltrelsize; 971 obj->pltrelsize = 0; 972 } 973 } 974 975 static void 976 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 977 const Elf_Dyn *dyn_soname) 978 { 979 980 if (obj->z_origin && obj->origin_path == NULL) { 981 obj->origin_path = xmalloc(PATH_MAX); 982 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 983 die(); 984 } 985 986 if (dyn_rpath != NULL) { 987 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 988 if (obj->z_origin) 989 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 990 } 991 992 if (dyn_soname != NULL) 993 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 994 } 995 996 static void 997 digest_dynamic(Obj_Entry *obj, int early) 998 { 999 const Elf_Dyn *dyn_rpath; 1000 const Elf_Dyn *dyn_soname; 1001 1002 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1003 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1004 } 1005 1006 /* 1007 * Process a shared object's program header. This is used only for the 1008 * main program, when the kernel has already loaded the main program 1009 * into memory before calling the dynamic linker. It creates and 1010 * returns an Obj_Entry structure. 1011 */ 1012 static Obj_Entry * 1013 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1014 { 1015 Obj_Entry *obj; 1016 const Elf_Phdr *phlimit = phdr + phnum; 1017 const Elf_Phdr *ph; 1018 int nsegs = 0; 1019 1020 obj = obj_new(); 1021 for (ph = phdr; ph < phlimit; ph++) { 1022 if (ph->p_type != PT_PHDR) 1023 continue; 1024 1025 obj->phdr = phdr; 1026 obj->phsize = ph->p_memsz; 1027 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1028 break; 1029 } 1030 1031 for (ph = phdr; ph < phlimit; ph++) { 1032 switch (ph->p_type) { 1033 1034 case PT_INTERP: 1035 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1036 break; 1037 1038 case PT_LOAD: 1039 if (nsegs == 0) { /* First load segment */ 1040 obj->vaddrbase = trunc_page(ph->p_vaddr); 1041 obj->mapbase = obj->vaddrbase + obj->relocbase; 1042 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1043 obj->vaddrbase; 1044 } else { /* Last load segment */ 1045 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1046 obj->vaddrbase; 1047 } 1048 nsegs++; 1049 break; 1050 1051 case PT_DYNAMIC: 1052 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1053 break; 1054 1055 case PT_TLS: 1056 obj->tlsindex = 1; 1057 obj->tlssize = ph->p_memsz; 1058 obj->tlsalign = ph->p_align; 1059 obj->tlsinitsize = ph->p_filesz; 1060 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1061 break; 1062 } 1063 } 1064 if (nsegs < 1) { 1065 _rtld_error("%s: too few PT_LOAD segments", path); 1066 return NULL; 1067 } 1068 1069 obj->entry = entry; 1070 return obj; 1071 } 1072 1073 static Obj_Entry * 1074 dlcheck(void *handle) 1075 { 1076 Obj_Entry *obj; 1077 1078 for (obj = obj_list; obj != NULL; obj = obj->next) 1079 if (obj == (Obj_Entry *) handle) 1080 break; 1081 1082 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1083 _rtld_error("Invalid shared object handle %p", handle); 1084 return NULL; 1085 } 1086 return obj; 1087 } 1088 1089 /* 1090 * If the given object is already in the donelist, return true. Otherwise 1091 * add the object to the list and return false. 1092 */ 1093 static bool 1094 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1095 { 1096 unsigned int i; 1097 1098 for (i = 0; i < dlp->num_used; i++) 1099 if (dlp->objs[i] == obj) 1100 return true; 1101 /* 1102 * Our donelist allocation should always be sufficient. But if 1103 * our threads locking isn't working properly, more shared objects 1104 * could have been loaded since we allocated the list. That should 1105 * never happen, but we'll handle it properly just in case it does. 1106 */ 1107 if (dlp->num_used < dlp->num_alloc) 1108 dlp->objs[dlp->num_used++] = obj; 1109 return false; 1110 } 1111 1112 /* 1113 * Hash function for symbol table lookup. Don't even think about changing 1114 * this. It is specified by the System V ABI. 1115 */ 1116 unsigned long 1117 elf_hash(const char *name) 1118 { 1119 const unsigned char *p = (const unsigned char *) name; 1120 unsigned long h = 0; 1121 unsigned long g; 1122 1123 while (*p != '\0') { 1124 h = (h << 4) + *p++; 1125 if ((g = h & 0xf0000000) != 0) 1126 h ^= g >> 24; 1127 h &= ~g; 1128 } 1129 return h; 1130 } 1131 1132 /* 1133 * Find the library with the given name, and return its full pathname. 1134 * The returned string is dynamically allocated. Generates an error 1135 * message and returns NULL if the library cannot be found. 1136 * 1137 * If the second argument is non-NULL, then it refers to an already- 1138 * loaded shared object, whose library search path will be searched. 1139 * 1140 * The search order is: 1141 * LD_LIBRARY_PATH 1142 * rpath in the referencing file 1143 * ldconfig hints 1144 * /lib:/usr/lib 1145 */ 1146 static char * 1147 find_library(const char *xname, const Obj_Entry *refobj) 1148 { 1149 char *pathname; 1150 char *name; 1151 1152 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1153 if (xname[0] != '/' && !trust) { 1154 _rtld_error("Absolute pathname required for shared object \"%s\"", 1155 xname); 1156 return NULL; 1157 } 1158 if (refobj != NULL && refobj->z_origin) 1159 return origin_subst(xname, refobj->origin_path); 1160 else 1161 return xstrdup(xname); 1162 } 1163 1164 if (libmap_disable || (refobj == NULL) || 1165 (name = lm_find(refobj->path, xname)) == NULL) 1166 name = (char *)xname; 1167 1168 dbg(" Searching for \"%s\"", name); 1169 1170 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1171 (refobj != NULL && 1172 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1173 (pathname = search_library_path(name, gethints())) != NULL || 1174 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1175 return pathname; 1176 1177 if(refobj != NULL && refobj->path != NULL) { 1178 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1179 name, basename(refobj->path)); 1180 } else { 1181 _rtld_error("Shared object \"%s\" not found", name); 1182 } 1183 return NULL; 1184 } 1185 1186 /* 1187 * Given a symbol number in a referencing object, find the corresponding 1188 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1189 * no definition was found. Returns a pointer to the Obj_Entry of the 1190 * defining object via the reference parameter DEFOBJ_OUT. 1191 */ 1192 const Elf_Sym * 1193 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1194 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1195 { 1196 const Elf_Sym *ref; 1197 const Elf_Sym *def; 1198 const Obj_Entry *defobj; 1199 const Ver_Entry *ventry; 1200 const char *name; 1201 unsigned long hash; 1202 1203 /* 1204 * If we have already found this symbol, get the information from 1205 * the cache. 1206 */ 1207 if (symnum >= refobj->nchains) 1208 return NULL; /* Bad object */ 1209 if (cache != NULL && cache[symnum].sym != NULL) { 1210 *defobj_out = cache[symnum].obj; 1211 return cache[symnum].sym; 1212 } 1213 1214 ref = refobj->symtab + symnum; 1215 name = refobj->strtab + ref->st_name; 1216 defobj = NULL; 1217 1218 /* 1219 * We don't have to do a full scale lookup if the symbol is local. 1220 * We know it will bind to the instance in this load module; to 1221 * which we already have a pointer (ie ref). By not doing a lookup, 1222 * we not only improve performance, but it also avoids unresolvable 1223 * symbols when local symbols are not in the hash table. This has 1224 * been seen with the ia64 toolchain. 1225 */ 1226 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1227 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1228 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1229 symnum); 1230 } 1231 ventry = fetch_ventry(refobj, symnum); 1232 hash = elf_hash(name); 1233 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1234 } else { 1235 def = ref; 1236 defobj = refobj; 1237 } 1238 1239 /* 1240 * If we found no definition and the reference is weak, treat the 1241 * symbol as having the value zero. 1242 */ 1243 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1244 def = &sym_zero; 1245 defobj = obj_main; 1246 } 1247 1248 if (def != NULL) { 1249 *defobj_out = defobj; 1250 /* Record the information in the cache to avoid subsequent lookups. */ 1251 if (cache != NULL) { 1252 cache[symnum].sym = def; 1253 cache[symnum].obj = defobj; 1254 } 1255 } else { 1256 if (refobj != &obj_rtld) 1257 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1258 } 1259 return def; 1260 } 1261 1262 /* 1263 * Return the search path from the ldconfig hints file, reading it if 1264 * necessary. Returns NULL if there are problems with the hints file, 1265 * or if the search path there is empty. 1266 */ 1267 static const char * 1268 gethints(void) 1269 { 1270 static char *hints; 1271 1272 if (hints == NULL) { 1273 int fd; 1274 struct elfhints_hdr hdr; 1275 char *p; 1276 1277 /* Keep from trying again in case the hints file is bad. */ 1278 hints = ""; 1279 1280 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1281 return NULL; 1282 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1283 hdr.magic != ELFHINTS_MAGIC || 1284 hdr.version != 1) { 1285 close(fd); 1286 return NULL; 1287 } 1288 p = xmalloc(hdr.dirlistlen + 1); 1289 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1290 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1291 free(p); 1292 close(fd); 1293 return NULL; 1294 } 1295 hints = p; 1296 close(fd); 1297 } 1298 return hints[0] != '\0' ? hints : NULL; 1299 } 1300 1301 static void 1302 init_dag(Obj_Entry *root) 1303 { 1304 DoneList donelist; 1305 1306 donelist_init(&donelist); 1307 init_dag1(root, root, &donelist); 1308 } 1309 1310 static void 1311 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1312 { 1313 const Needed_Entry *needed; 1314 1315 if (donelist_check(dlp, obj)) 1316 return; 1317 1318 obj->refcount++; 1319 objlist_push_tail(&obj->dldags, root); 1320 objlist_push_tail(&root->dagmembers, obj); 1321 for (needed = obj->needed; needed != NULL; needed = needed->next) 1322 if (needed->obj != NULL) 1323 init_dag1(root, needed->obj, dlp); 1324 } 1325 1326 /* 1327 * Initialize the dynamic linker. The argument is the address at which 1328 * the dynamic linker has been mapped into memory. The primary task of 1329 * this function is to relocate the dynamic linker. 1330 */ 1331 static void 1332 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1333 { 1334 Obj_Entry objtmp; /* Temporary rtld object */ 1335 const Elf_Dyn *dyn_rpath; 1336 const Elf_Dyn *dyn_soname; 1337 1338 /* 1339 * Conjure up an Obj_Entry structure for the dynamic linker. 1340 * 1341 * The "path" member can't be initialized yet because string constants 1342 * cannot yet be accessed. Below we will set it correctly. 1343 */ 1344 memset(&objtmp, 0, sizeof(objtmp)); 1345 objtmp.path = NULL; 1346 objtmp.rtld = true; 1347 objtmp.mapbase = mapbase; 1348 #ifdef PIC 1349 objtmp.relocbase = mapbase; 1350 #endif 1351 if (RTLD_IS_DYNAMIC()) { 1352 objtmp.dynamic = rtld_dynamic(&objtmp); 1353 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1354 assert(objtmp.needed == NULL); 1355 #if !defined(__mips__) 1356 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1357 assert(!objtmp.textrel); 1358 #endif 1359 1360 /* 1361 * Temporarily put the dynamic linker entry into the object list, so 1362 * that symbols can be found. 1363 */ 1364 1365 relocate_objects(&objtmp, true, &objtmp); 1366 } 1367 1368 /* Initialize the object list. */ 1369 obj_tail = &obj_list; 1370 1371 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1372 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1373 1374 if (aux_info[AT_PAGESZ] != NULL) 1375 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1376 if (aux_info[AT_OSRELDATE] != NULL) 1377 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1378 1379 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1380 1381 /* Replace the path with a dynamically allocated copy. */ 1382 obj_rtld.path = xstrdup(PATH_RTLD); 1383 1384 r_debug.r_brk = r_debug_state; 1385 r_debug.r_state = RT_CONSISTENT; 1386 } 1387 1388 /* 1389 * Add the init functions from a needed object list (and its recursive 1390 * needed objects) to "list". This is not used directly; it is a helper 1391 * function for initlist_add_objects(). The write lock must be held 1392 * when this function is called. 1393 */ 1394 static void 1395 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1396 { 1397 /* Recursively process the successor needed objects. */ 1398 if (needed->next != NULL) 1399 initlist_add_neededs(needed->next, list); 1400 1401 /* Process the current needed object. */ 1402 if (needed->obj != NULL) 1403 initlist_add_objects(needed->obj, &needed->obj->next, list); 1404 } 1405 1406 /* 1407 * Scan all of the DAGs rooted in the range of objects from "obj" to 1408 * "tail" and add their init functions to "list". This recurses over 1409 * the DAGs and ensure the proper init ordering such that each object's 1410 * needed libraries are initialized before the object itself. At the 1411 * same time, this function adds the objects to the global finalization 1412 * list "list_fini" in the opposite order. The write lock must be 1413 * held when this function is called. 1414 */ 1415 static void 1416 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1417 { 1418 if (obj->init_scanned || obj->init_done) 1419 return; 1420 obj->init_scanned = true; 1421 1422 /* Recursively process the successor objects. */ 1423 if (&obj->next != tail) 1424 initlist_add_objects(obj->next, tail, list); 1425 1426 /* Recursively process the needed objects. */ 1427 if (obj->needed != NULL) 1428 initlist_add_neededs(obj->needed, list); 1429 1430 /* Add the object to the init list. */ 1431 if (obj->init != (Elf_Addr)NULL) 1432 objlist_push_tail(list, obj); 1433 1434 /* Add the object to the global fini list in the reverse order. */ 1435 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1436 objlist_push_head(&list_fini, obj); 1437 obj->on_fini_list = true; 1438 } 1439 } 1440 1441 #ifndef FPTR_TARGET 1442 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1443 #endif 1444 1445 static bool 1446 is_exported(const Elf_Sym *def) 1447 { 1448 Elf_Addr value; 1449 const func_ptr_type *p; 1450 1451 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1452 for (p = exports; *p != NULL; p++) 1453 if (FPTR_TARGET(*p) == value) 1454 return true; 1455 return false; 1456 } 1457 1458 /* 1459 * Given a shared object, traverse its list of needed objects, and load 1460 * each of them. Returns 0 on success. Generates an error message and 1461 * returns -1 on failure. 1462 */ 1463 static int 1464 load_needed_objects(Obj_Entry *first, int flags) 1465 { 1466 Obj_Entry *obj, *obj1; 1467 1468 for (obj = first; obj != NULL; obj = obj->next) { 1469 Needed_Entry *needed; 1470 1471 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1472 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1473 flags & ~RTLD_LO_NOLOAD); 1474 if (obj1 == NULL && !ld_tracing) 1475 return -1; 1476 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1477 dbg("obj %s nodelete", obj1->path); 1478 init_dag(obj1); 1479 ref_dag(obj1); 1480 obj1->ref_nodel = true; 1481 } 1482 } 1483 } 1484 1485 return 0; 1486 } 1487 1488 static int 1489 load_preload_objects(void) 1490 { 1491 char *p = ld_preload; 1492 static const char delim[] = " \t:;"; 1493 1494 if (p == NULL) 1495 return 0; 1496 1497 p += strspn(p, delim); 1498 while (*p != '\0') { 1499 size_t len = strcspn(p, delim); 1500 char savech; 1501 1502 savech = p[len]; 1503 p[len] = '\0'; 1504 if (load_object(p, NULL, 0) == NULL) 1505 return -1; /* XXX - cleanup */ 1506 p[len] = savech; 1507 p += len; 1508 p += strspn(p, delim); 1509 } 1510 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1511 return 0; 1512 } 1513 1514 /* 1515 * Load a shared object into memory, if it is not already loaded. 1516 * 1517 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1518 * on failure. 1519 */ 1520 static Obj_Entry * 1521 load_object(const char *name, const Obj_Entry *refobj, int flags) 1522 { 1523 Obj_Entry *obj; 1524 int fd = -1; 1525 struct stat sb; 1526 char *path; 1527 1528 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1529 if (object_match_name(obj, name)) 1530 return obj; 1531 1532 path = find_library(name, refobj); 1533 if (path == NULL) 1534 return NULL; 1535 1536 /* 1537 * If we didn't find a match by pathname, open the file and check 1538 * again by device and inode. This avoids false mismatches caused 1539 * by multiple links or ".." in pathnames. 1540 * 1541 * To avoid a race, we open the file and use fstat() rather than 1542 * using stat(). 1543 */ 1544 if ((fd = open(path, O_RDONLY)) == -1) { 1545 _rtld_error("Cannot open \"%s\"", path); 1546 free(path); 1547 return NULL; 1548 } 1549 if (fstat(fd, &sb) == -1) { 1550 _rtld_error("Cannot fstat \"%s\"", path); 1551 close(fd); 1552 free(path); 1553 return NULL; 1554 } 1555 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1556 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1557 close(fd); 1558 break; 1559 } 1560 } 1561 if (obj != NULL) { 1562 object_add_name(obj, name); 1563 free(path); 1564 close(fd); 1565 return obj; 1566 } 1567 if (flags & RTLD_LO_NOLOAD) { 1568 free(path); 1569 return (NULL); 1570 } 1571 1572 /* First use of this object, so we must map it in */ 1573 obj = do_load_object(fd, name, path, &sb, flags); 1574 if (obj == NULL) 1575 free(path); 1576 close(fd); 1577 1578 return obj; 1579 } 1580 1581 static Obj_Entry * 1582 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1583 int flags) 1584 { 1585 Obj_Entry *obj; 1586 struct statfs fs; 1587 1588 /* 1589 * but first, make sure that environment variables haven't been 1590 * used to circumvent the noexec flag on a filesystem. 1591 */ 1592 if (dangerous_ld_env) { 1593 if (fstatfs(fd, &fs) != 0) { 1594 _rtld_error("Cannot fstatfs \"%s\"", path); 1595 return NULL; 1596 } 1597 if (fs.f_flags & MNT_NOEXEC) { 1598 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1599 return NULL; 1600 } 1601 } 1602 dbg("loading \"%s\"", path); 1603 obj = map_object(fd, path, sbp); 1604 if (obj == NULL) 1605 return NULL; 1606 1607 object_add_name(obj, name); 1608 obj->path = path; 1609 digest_dynamic(obj, 0); 1610 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1611 RTLD_LO_DLOPEN) { 1612 dbg("refusing to load non-loadable \"%s\"", obj->path); 1613 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1614 munmap(obj->mapbase, obj->mapsize); 1615 obj_free(obj); 1616 return (NULL); 1617 } 1618 1619 *obj_tail = obj; 1620 obj_tail = &obj->next; 1621 obj_count++; 1622 obj_loads++; 1623 linkmap_add(obj); /* for GDB & dlinfo() */ 1624 1625 dbg(" %p .. %p: %s", obj->mapbase, 1626 obj->mapbase + obj->mapsize - 1, obj->path); 1627 if (obj->textrel) 1628 dbg(" WARNING: %s has impure text", obj->path); 1629 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1630 obj->path); 1631 1632 return obj; 1633 } 1634 1635 static Obj_Entry * 1636 obj_from_addr(const void *addr) 1637 { 1638 Obj_Entry *obj; 1639 1640 for (obj = obj_list; obj != NULL; obj = obj->next) { 1641 if (addr < (void *) obj->mapbase) 1642 continue; 1643 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1644 return obj; 1645 } 1646 return NULL; 1647 } 1648 1649 /* 1650 * Call the finalization functions for each of the objects in "list" 1651 * which are unreferenced. All of the objects are expected to have 1652 * non-NULL fini functions. 1653 */ 1654 static void 1655 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1656 { 1657 Objlist_Entry *elm, *elm_tmp; 1658 char *saved_msg; 1659 1660 /* 1661 * Preserve the current error message since a fini function might 1662 * call into the dynamic linker and overwrite it. 1663 */ 1664 saved_msg = errmsg_save(); 1665 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1666 if (elm->obj->refcount == 0 || force) { 1667 dbg("calling fini function for %s at %p", elm->obj->path, 1668 (void *)elm->obj->fini); 1669 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1670 elm->obj->path); 1671 /* Remove object from fini list to prevent recursive invocation. */ 1672 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1673 wlock_release(rtld_bind_lock, *lockstate); 1674 call_initfini_pointer(elm->obj, elm->obj->fini); 1675 *lockstate = wlock_acquire(rtld_bind_lock); 1676 /* No need to free anything if process is going down. */ 1677 if (!force) 1678 free(elm); 1679 } 1680 } 1681 errmsg_restore(saved_msg); 1682 } 1683 1684 /* 1685 * Call the initialization functions for each of the objects in 1686 * "list". All of the objects are expected to have non-NULL init 1687 * functions. 1688 */ 1689 static void 1690 objlist_call_init(Objlist *list, int *lockstate) 1691 { 1692 Objlist_Entry *elm; 1693 Obj_Entry *obj; 1694 char *saved_msg; 1695 1696 /* 1697 * Clean init_scanned flag so that objects can be rechecked and 1698 * possibly initialized earlier if any of vectors called below 1699 * cause the change by using dlopen. 1700 */ 1701 for (obj = obj_list; obj != NULL; obj = obj->next) 1702 obj->init_scanned = false; 1703 1704 /* 1705 * Preserve the current error message since an init function might 1706 * call into the dynamic linker and overwrite it. 1707 */ 1708 saved_msg = errmsg_save(); 1709 STAILQ_FOREACH(elm, list, link) { 1710 if (elm->obj->init_done) /* Initialized early. */ 1711 continue; 1712 dbg("calling init function for %s at %p", elm->obj->path, 1713 (void *)elm->obj->init); 1714 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1715 elm->obj->path); 1716 /* 1717 * Race: other thread might try to use this object before current 1718 * one completes the initilization. Not much can be done here 1719 * without better locking. 1720 */ 1721 elm->obj->init_done = true; 1722 wlock_release(rtld_bind_lock, *lockstate); 1723 call_initfini_pointer(elm->obj, elm->obj->init); 1724 *lockstate = wlock_acquire(rtld_bind_lock); 1725 } 1726 errmsg_restore(saved_msg); 1727 } 1728 1729 static void 1730 objlist_clear(Objlist *list) 1731 { 1732 Objlist_Entry *elm; 1733 1734 while (!STAILQ_EMPTY(list)) { 1735 elm = STAILQ_FIRST(list); 1736 STAILQ_REMOVE_HEAD(list, link); 1737 free(elm); 1738 } 1739 } 1740 1741 static Objlist_Entry * 1742 objlist_find(Objlist *list, const Obj_Entry *obj) 1743 { 1744 Objlist_Entry *elm; 1745 1746 STAILQ_FOREACH(elm, list, link) 1747 if (elm->obj == obj) 1748 return elm; 1749 return NULL; 1750 } 1751 1752 static void 1753 objlist_init(Objlist *list) 1754 { 1755 STAILQ_INIT(list); 1756 } 1757 1758 static void 1759 objlist_push_head(Objlist *list, Obj_Entry *obj) 1760 { 1761 Objlist_Entry *elm; 1762 1763 elm = NEW(Objlist_Entry); 1764 elm->obj = obj; 1765 STAILQ_INSERT_HEAD(list, elm, link); 1766 } 1767 1768 static void 1769 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1770 { 1771 Objlist_Entry *elm; 1772 1773 elm = NEW(Objlist_Entry); 1774 elm->obj = obj; 1775 STAILQ_INSERT_TAIL(list, elm, link); 1776 } 1777 1778 static void 1779 objlist_remove(Objlist *list, Obj_Entry *obj) 1780 { 1781 Objlist_Entry *elm; 1782 1783 if ((elm = objlist_find(list, obj)) != NULL) { 1784 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1785 free(elm); 1786 } 1787 } 1788 1789 /* 1790 * Relocate newly-loaded shared objects. The argument is a pointer to 1791 * the Obj_Entry for the first such object. All objects from the first 1792 * to the end of the list of objects are relocated. Returns 0 on success, 1793 * or -1 on failure. 1794 */ 1795 static int 1796 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1797 { 1798 Obj_Entry *obj; 1799 1800 for (obj = first; obj != NULL; obj = obj->next) { 1801 if (obj != rtldobj) 1802 dbg("relocating \"%s\"", obj->path); 1803 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1804 obj->symtab == NULL || obj->strtab == NULL) { 1805 _rtld_error("%s: Shared object has no run-time symbol table", 1806 obj->path); 1807 return -1; 1808 } 1809 1810 if (obj->textrel) { 1811 /* There are relocations to the write-protected text segment. */ 1812 if (mprotect(obj->mapbase, obj->textsize, 1813 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1814 _rtld_error("%s: Cannot write-enable text segment: %s", 1815 obj->path, strerror(errno)); 1816 return -1; 1817 } 1818 } 1819 1820 /* Process the non-PLT relocations. */ 1821 if (reloc_non_plt(obj, rtldobj)) 1822 return -1; 1823 1824 if (obj->textrel) { /* Re-protected the text segment. */ 1825 if (mprotect(obj->mapbase, obj->textsize, 1826 PROT_READ|PROT_EXEC) == -1) { 1827 _rtld_error("%s: Cannot write-protect text segment: %s", 1828 obj->path, strerror(errno)); 1829 return -1; 1830 } 1831 } 1832 1833 /* Process the PLT relocations. */ 1834 if (reloc_plt(obj) == -1) 1835 return -1; 1836 /* Relocate the jump slots if we are doing immediate binding. */ 1837 if (obj->bind_now || bind_now) 1838 if (reloc_jmpslots(obj) == -1) 1839 return -1; 1840 1841 1842 /* 1843 * Set up the magic number and version in the Obj_Entry. These 1844 * were checked in the crt1.o from the original ElfKit, so we 1845 * set them for backward compatibility. 1846 */ 1847 obj->magic = RTLD_MAGIC; 1848 obj->version = RTLD_VERSION; 1849 1850 /* Set the special PLT or GOT entries. */ 1851 init_pltgot(obj); 1852 } 1853 1854 return 0; 1855 } 1856 1857 /* 1858 * Cleanup procedure. It will be called (by the atexit mechanism) just 1859 * before the process exits. 1860 */ 1861 static void 1862 rtld_exit(void) 1863 { 1864 int lockstate; 1865 1866 lockstate = wlock_acquire(rtld_bind_lock); 1867 dbg("rtld_exit()"); 1868 objlist_call_fini(&list_fini, true, &lockstate); 1869 /* No need to remove the items from the list, since we are exiting. */ 1870 if (!libmap_disable) 1871 lm_fini(); 1872 wlock_release(rtld_bind_lock, lockstate); 1873 } 1874 1875 static void * 1876 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1877 { 1878 #ifdef COMPAT_32BIT 1879 const char *trans; 1880 #endif 1881 if (path == NULL) 1882 return (NULL); 1883 1884 path += strspn(path, ":;"); 1885 while (*path != '\0') { 1886 size_t len; 1887 char *res; 1888 1889 len = strcspn(path, ":;"); 1890 #ifdef COMPAT_32BIT 1891 trans = lm_findn(NULL, path, len); 1892 if (trans) 1893 res = callback(trans, strlen(trans), arg); 1894 else 1895 #endif 1896 res = callback(path, len, arg); 1897 1898 if (res != NULL) 1899 return (res); 1900 1901 path += len; 1902 path += strspn(path, ":;"); 1903 } 1904 1905 return (NULL); 1906 } 1907 1908 struct try_library_args { 1909 const char *name; 1910 size_t namelen; 1911 char *buffer; 1912 size_t buflen; 1913 }; 1914 1915 static void * 1916 try_library_path(const char *dir, size_t dirlen, void *param) 1917 { 1918 struct try_library_args *arg; 1919 1920 arg = param; 1921 if (*dir == '/' || trust) { 1922 char *pathname; 1923 1924 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1925 return (NULL); 1926 1927 pathname = arg->buffer; 1928 strncpy(pathname, dir, dirlen); 1929 pathname[dirlen] = '/'; 1930 strcpy(pathname + dirlen + 1, arg->name); 1931 1932 dbg(" Trying \"%s\"", pathname); 1933 if (access(pathname, F_OK) == 0) { /* We found it */ 1934 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1935 strcpy(pathname, arg->buffer); 1936 return (pathname); 1937 } 1938 } 1939 return (NULL); 1940 } 1941 1942 static char * 1943 search_library_path(const char *name, const char *path) 1944 { 1945 char *p; 1946 struct try_library_args arg; 1947 1948 if (path == NULL) 1949 return NULL; 1950 1951 arg.name = name; 1952 arg.namelen = strlen(name); 1953 arg.buffer = xmalloc(PATH_MAX); 1954 arg.buflen = PATH_MAX; 1955 1956 p = path_enumerate(path, try_library_path, &arg); 1957 1958 free(arg.buffer); 1959 1960 return (p); 1961 } 1962 1963 int 1964 dlclose(void *handle) 1965 { 1966 Obj_Entry *root; 1967 int lockstate; 1968 1969 lockstate = wlock_acquire(rtld_bind_lock); 1970 root = dlcheck(handle); 1971 if (root == NULL) { 1972 wlock_release(rtld_bind_lock, lockstate); 1973 return -1; 1974 } 1975 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1976 root->path); 1977 1978 /* Unreference the object and its dependencies. */ 1979 root->dl_refcount--; 1980 1981 unref_dag(root); 1982 1983 if (root->refcount == 0) { 1984 /* 1985 * The object is no longer referenced, so we must unload it. 1986 * First, call the fini functions. 1987 */ 1988 objlist_call_fini(&list_fini, false, &lockstate); 1989 1990 /* Finish cleaning up the newly-unreferenced objects. */ 1991 GDB_STATE(RT_DELETE,&root->linkmap); 1992 unload_object(root); 1993 GDB_STATE(RT_CONSISTENT,NULL); 1994 } 1995 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1996 wlock_release(rtld_bind_lock, lockstate); 1997 return 0; 1998 } 1999 2000 char * 2001 dlerror(void) 2002 { 2003 char *msg = error_message; 2004 error_message = NULL; 2005 return msg; 2006 } 2007 2008 /* 2009 * This function is deprecated and has no effect. 2010 */ 2011 void 2012 dllockinit(void *context, 2013 void *(*lock_create)(void *context), 2014 void (*rlock_acquire)(void *lock), 2015 void (*wlock_acquire)(void *lock), 2016 void (*lock_release)(void *lock), 2017 void (*lock_destroy)(void *lock), 2018 void (*context_destroy)(void *context)) 2019 { 2020 static void *cur_context; 2021 static void (*cur_context_destroy)(void *); 2022 2023 /* Just destroy the context from the previous call, if necessary. */ 2024 if (cur_context_destroy != NULL) 2025 cur_context_destroy(cur_context); 2026 cur_context = context; 2027 cur_context_destroy = context_destroy; 2028 } 2029 2030 void * 2031 dlopen(const char *name, int mode) 2032 { 2033 Obj_Entry **old_obj_tail; 2034 Obj_Entry *obj; 2035 Objlist initlist; 2036 int result, lockstate, nodelete, lo_flags; 2037 2038 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2039 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2040 if (ld_tracing != NULL) 2041 environ = (char **)*get_program_var_addr("environ"); 2042 nodelete = mode & RTLD_NODELETE; 2043 lo_flags = RTLD_LO_DLOPEN; 2044 if (mode & RTLD_NOLOAD) 2045 lo_flags |= RTLD_LO_NOLOAD; 2046 if (ld_tracing != NULL) 2047 lo_flags |= RTLD_LO_TRACE; 2048 2049 objlist_init(&initlist); 2050 2051 lockstate = wlock_acquire(rtld_bind_lock); 2052 GDB_STATE(RT_ADD,NULL); 2053 2054 old_obj_tail = obj_tail; 2055 obj = NULL; 2056 if (name == NULL) { 2057 obj = obj_main; 2058 obj->refcount++; 2059 } else { 2060 obj = load_object(name, obj_main, lo_flags); 2061 } 2062 2063 if (obj) { 2064 obj->dl_refcount++; 2065 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2066 objlist_push_tail(&list_global, obj); 2067 mode &= RTLD_MODEMASK; 2068 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2069 assert(*old_obj_tail == obj); 2070 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2071 init_dag(obj); 2072 if (result != -1) 2073 result = rtld_verify_versions(&obj->dagmembers); 2074 if (result != -1 && ld_tracing) 2075 goto trace; 2076 if (result == -1 || 2077 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2078 obj->dl_refcount--; 2079 unref_dag(obj); 2080 if (obj->refcount == 0) 2081 unload_object(obj); 2082 obj = NULL; 2083 } else { 2084 /* Make list of init functions to call. */ 2085 initlist_add_objects(obj, &obj->next, &initlist); 2086 } 2087 } else { 2088 2089 /* Bump the reference counts for objects on this DAG. */ 2090 ref_dag(obj); 2091 2092 if (ld_tracing) 2093 goto trace; 2094 } 2095 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2096 dbg("obj %s nodelete", obj->path); 2097 ref_dag(obj); 2098 obj->z_nodelete = obj->ref_nodel = true; 2099 } 2100 } 2101 2102 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2103 name); 2104 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2105 2106 /* Call the init functions. */ 2107 objlist_call_init(&initlist, &lockstate); 2108 objlist_clear(&initlist); 2109 wlock_release(rtld_bind_lock, lockstate); 2110 return obj; 2111 trace: 2112 trace_loaded_objects(obj); 2113 wlock_release(rtld_bind_lock, lockstate); 2114 exit(0); 2115 } 2116 2117 static void * 2118 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2119 int flags) 2120 { 2121 DoneList donelist; 2122 const Obj_Entry *obj, *defobj; 2123 const Elf_Sym *def, *symp; 2124 unsigned long hash; 2125 int lockstate; 2126 2127 hash = elf_hash(name); 2128 def = NULL; 2129 defobj = NULL; 2130 flags |= SYMLOOK_IN_PLT; 2131 2132 lockstate = rlock_acquire(rtld_bind_lock); 2133 if (handle == NULL || handle == RTLD_NEXT || 2134 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2135 2136 if ((obj = obj_from_addr(retaddr)) == NULL) { 2137 _rtld_error("Cannot determine caller's shared object"); 2138 rlock_release(rtld_bind_lock, lockstate); 2139 return NULL; 2140 } 2141 if (handle == NULL) { /* Just the caller's shared object. */ 2142 def = symlook_obj(name, hash, obj, ve, flags); 2143 defobj = obj; 2144 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2145 handle == RTLD_SELF) { /* ... caller included */ 2146 if (handle == RTLD_NEXT) 2147 obj = obj->next; 2148 for (; obj != NULL; obj = obj->next) { 2149 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2150 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2151 def = symp; 2152 defobj = obj; 2153 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2154 break; 2155 } 2156 } 2157 } 2158 /* 2159 * Search the dynamic linker itself, and possibly resolve the 2160 * symbol from there. This is how the application links to 2161 * dynamic linker services such as dlopen. Only the values listed 2162 * in the "exports" array can be resolved from the dynamic linker. 2163 */ 2164 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2165 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2166 if (symp != NULL && is_exported(symp)) { 2167 def = symp; 2168 defobj = &obj_rtld; 2169 } 2170 } 2171 } else { 2172 assert(handle == RTLD_DEFAULT); 2173 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2174 } 2175 } else { 2176 if ((obj = dlcheck(handle)) == NULL) { 2177 rlock_release(rtld_bind_lock, lockstate); 2178 return NULL; 2179 } 2180 2181 donelist_init(&donelist); 2182 if (obj->mainprog) { 2183 /* Search main program and all libraries loaded by it. */ 2184 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2185 &donelist); 2186 2187 /* 2188 * We do not distinguish between 'main' object and global scope. 2189 * If symbol is not defined by objects loaded at startup, continue 2190 * search among dynamically loaded objects with RTLD_GLOBAL 2191 * scope. 2192 */ 2193 if (def == NULL) 2194 def = symlook_list(name, hash, &list_global, &defobj, ve, 2195 flags, &donelist); 2196 } else { 2197 Needed_Entry fake; 2198 2199 /* Search the whole DAG rooted at the given object. */ 2200 fake.next = NULL; 2201 fake.obj = (Obj_Entry *)obj; 2202 fake.name = 0; 2203 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2204 &donelist); 2205 } 2206 } 2207 2208 if (def != NULL) { 2209 rlock_release(rtld_bind_lock, lockstate); 2210 2211 /* 2212 * The value required by the caller is derived from the value 2213 * of the symbol. For the ia64 architecture, we need to 2214 * construct a function descriptor which the caller can use to 2215 * call the function with the right 'gp' value. For other 2216 * architectures and for non-functions, the value is simply 2217 * the relocated value of the symbol. 2218 */ 2219 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2220 return make_function_pointer(def, defobj); 2221 else 2222 return defobj->relocbase + def->st_value; 2223 } 2224 2225 _rtld_error("Undefined symbol \"%s\"", name); 2226 rlock_release(rtld_bind_lock, lockstate); 2227 return NULL; 2228 } 2229 2230 void * 2231 dlsym(void *handle, const char *name) 2232 { 2233 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2234 SYMLOOK_DLSYM); 2235 } 2236 2237 dlfunc_t 2238 dlfunc(void *handle, const char *name) 2239 { 2240 union { 2241 void *d; 2242 dlfunc_t f; 2243 } rv; 2244 2245 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2246 SYMLOOK_DLSYM); 2247 return (rv.f); 2248 } 2249 2250 void * 2251 dlvsym(void *handle, const char *name, const char *version) 2252 { 2253 Ver_Entry ventry; 2254 2255 ventry.name = version; 2256 ventry.file = NULL; 2257 ventry.hash = elf_hash(version); 2258 ventry.flags= 0; 2259 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2260 SYMLOOK_DLSYM); 2261 } 2262 2263 int 2264 dladdr(const void *addr, Dl_info *info) 2265 { 2266 const Obj_Entry *obj; 2267 const Elf_Sym *def; 2268 void *symbol_addr; 2269 unsigned long symoffset; 2270 int lockstate; 2271 2272 lockstate = rlock_acquire(rtld_bind_lock); 2273 obj = obj_from_addr(addr); 2274 if (obj == NULL) { 2275 _rtld_error("No shared object contains address"); 2276 rlock_release(rtld_bind_lock, lockstate); 2277 return 0; 2278 } 2279 info->dli_fname = obj->path; 2280 info->dli_fbase = obj->mapbase; 2281 info->dli_saddr = (void *)0; 2282 info->dli_sname = NULL; 2283 2284 /* 2285 * Walk the symbol list looking for the symbol whose address is 2286 * closest to the address sent in. 2287 */ 2288 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2289 def = obj->symtab + symoffset; 2290 2291 /* 2292 * For skip the symbol if st_shndx is either SHN_UNDEF or 2293 * SHN_COMMON. 2294 */ 2295 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2296 continue; 2297 2298 /* 2299 * If the symbol is greater than the specified address, or if it 2300 * is further away from addr than the current nearest symbol, 2301 * then reject it. 2302 */ 2303 symbol_addr = obj->relocbase + def->st_value; 2304 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2305 continue; 2306 2307 /* Update our idea of the nearest symbol. */ 2308 info->dli_sname = obj->strtab + def->st_name; 2309 info->dli_saddr = symbol_addr; 2310 2311 /* Exact match? */ 2312 if (info->dli_saddr == addr) 2313 break; 2314 } 2315 rlock_release(rtld_bind_lock, lockstate); 2316 return 1; 2317 } 2318 2319 int 2320 dlinfo(void *handle, int request, void *p) 2321 { 2322 const Obj_Entry *obj; 2323 int error, lockstate; 2324 2325 lockstate = rlock_acquire(rtld_bind_lock); 2326 2327 if (handle == NULL || handle == RTLD_SELF) { 2328 void *retaddr; 2329 2330 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2331 if ((obj = obj_from_addr(retaddr)) == NULL) 2332 _rtld_error("Cannot determine caller's shared object"); 2333 } else 2334 obj = dlcheck(handle); 2335 2336 if (obj == NULL) { 2337 rlock_release(rtld_bind_lock, lockstate); 2338 return (-1); 2339 } 2340 2341 error = 0; 2342 switch (request) { 2343 case RTLD_DI_LINKMAP: 2344 *((struct link_map const **)p) = &obj->linkmap; 2345 break; 2346 case RTLD_DI_ORIGIN: 2347 error = rtld_dirname(obj->path, p); 2348 break; 2349 2350 case RTLD_DI_SERINFOSIZE: 2351 case RTLD_DI_SERINFO: 2352 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2353 break; 2354 2355 default: 2356 _rtld_error("Invalid request %d passed to dlinfo()", request); 2357 error = -1; 2358 } 2359 2360 rlock_release(rtld_bind_lock, lockstate); 2361 2362 return (error); 2363 } 2364 2365 int 2366 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2367 { 2368 struct dl_phdr_info phdr_info; 2369 const Obj_Entry *obj; 2370 int error, bind_lockstate, phdr_lockstate; 2371 2372 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2373 bind_lockstate = rlock_acquire(rtld_bind_lock); 2374 2375 error = 0; 2376 2377 for (obj = obj_list; obj != NULL; obj = obj->next) { 2378 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2379 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2380 STAILQ_FIRST(&obj->names)->name : obj->path; 2381 phdr_info.dlpi_phdr = obj->phdr; 2382 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2383 phdr_info.dlpi_tls_modid = obj->tlsindex; 2384 phdr_info.dlpi_tls_data = obj->tlsinit; 2385 phdr_info.dlpi_adds = obj_loads; 2386 phdr_info.dlpi_subs = obj_loads - obj_count; 2387 2388 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2389 break; 2390 2391 } 2392 rlock_release(rtld_bind_lock, bind_lockstate); 2393 wlock_release(rtld_phdr_lock, phdr_lockstate); 2394 2395 return (error); 2396 } 2397 2398 struct fill_search_info_args { 2399 int request; 2400 unsigned int flags; 2401 Dl_serinfo *serinfo; 2402 Dl_serpath *serpath; 2403 char *strspace; 2404 }; 2405 2406 static void * 2407 fill_search_info(const char *dir, size_t dirlen, void *param) 2408 { 2409 struct fill_search_info_args *arg; 2410 2411 arg = param; 2412 2413 if (arg->request == RTLD_DI_SERINFOSIZE) { 2414 arg->serinfo->dls_cnt ++; 2415 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2416 } else { 2417 struct dl_serpath *s_entry; 2418 2419 s_entry = arg->serpath; 2420 s_entry->dls_name = arg->strspace; 2421 s_entry->dls_flags = arg->flags; 2422 2423 strncpy(arg->strspace, dir, dirlen); 2424 arg->strspace[dirlen] = '\0'; 2425 2426 arg->strspace += dirlen + 1; 2427 arg->serpath++; 2428 } 2429 2430 return (NULL); 2431 } 2432 2433 static int 2434 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2435 { 2436 struct dl_serinfo _info; 2437 struct fill_search_info_args args; 2438 2439 args.request = RTLD_DI_SERINFOSIZE; 2440 args.serinfo = &_info; 2441 2442 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2443 _info.dls_cnt = 0; 2444 2445 path_enumerate(ld_library_path, fill_search_info, &args); 2446 path_enumerate(obj->rpath, fill_search_info, &args); 2447 path_enumerate(gethints(), fill_search_info, &args); 2448 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2449 2450 2451 if (request == RTLD_DI_SERINFOSIZE) { 2452 info->dls_size = _info.dls_size; 2453 info->dls_cnt = _info.dls_cnt; 2454 return (0); 2455 } 2456 2457 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2458 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2459 return (-1); 2460 } 2461 2462 args.request = RTLD_DI_SERINFO; 2463 args.serinfo = info; 2464 args.serpath = &info->dls_serpath[0]; 2465 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2466 2467 args.flags = LA_SER_LIBPATH; 2468 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2469 return (-1); 2470 2471 args.flags = LA_SER_RUNPATH; 2472 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2473 return (-1); 2474 2475 args.flags = LA_SER_CONFIG; 2476 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2477 return (-1); 2478 2479 args.flags = LA_SER_DEFAULT; 2480 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2481 return (-1); 2482 return (0); 2483 } 2484 2485 static int 2486 rtld_dirname(const char *path, char *bname) 2487 { 2488 const char *endp; 2489 2490 /* Empty or NULL string gets treated as "." */ 2491 if (path == NULL || *path == '\0') { 2492 bname[0] = '.'; 2493 bname[1] = '\0'; 2494 return (0); 2495 } 2496 2497 /* Strip trailing slashes */ 2498 endp = path + strlen(path) - 1; 2499 while (endp > path && *endp == '/') 2500 endp--; 2501 2502 /* Find the start of the dir */ 2503 while (endp > path && *endp != '/') 2504 endp--; 2505 2506 /* Either the dir is "/" or there are no slashes */ 2507 if (endp == path) { 2508 bname[0] = *endp == '/' ? '/' : '.'; 2509 bname[1] = '\0'; 2510 return (0); 2511 } else { 2512 do { 2513 endp--; 2514 } while (endp > path && *endp == '/'); 2515 } 2516 2517 if (endp - path + 2 > PATH_MAX) 2518 { 2519 _rtld_error("Filename is too long: %s", path); 2520 return(-1); 2521 } 2522 2523 strncpy(bname, path, endp - path + 1); 2524 bname[endp - path + 1] = '\0'; 2525 return (0); 2526 } 2527 2528 static int 2529 rtld_dirname_abs(const char *path, char *base) 2530 { 2531 char base_rel[PATH_MAX]; 2532 2533 if (rtld_dirname(path, base) == -1) 2534 return (-1); 2535 if (base[0] == '/') 2536 return (0); 2537 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2538 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2539 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2540 return (-1); 2541 strcpy(base, base_rel); 2542 return (0); 2543 } 2544 2545 static void 2546 linkmap_add(Obj_Entry *obj) 2547 { 2548 struct link_map *l = &obj->linkmap; 2549 struct link_map *prev; 2550 2551 obj->linkmap.l_name = obj->path; 2552 obj->linkmap.l_addr = obj->mapbase; 2553 obj->linkmap.l_ld = obj->dynamic; 2554 #ifdef __mips__ 2555 /* GDB needs load offset on MIPS to use the symbols */ 2556 obj->linkmap.l_offs = obj->relocbase; 2557 #endif 2558 2559 if (r_debug.r_map == NULL) { 2560 r_debug.r_map = l; 2561 return; 2562 } 2563 2564 /* 2565 * Scan to the end of the list, but not past the entry for the 2566 * dynamic linker, which we want to keep at the very end. 2567 */ 2568 for (prev = r_debug.r_map; 2569 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2570 prev = prev->l_next) 2571 ; 2572 2573 /* Link in the new entry. */ 2574 l->l_prev = prev; 2575 l->l_next = prev->l_next; 2576 if (l->l_next != NULL) 2577 l->l_next->l_prev = l; 2578 prev->l_next = l; 2579 } 2580 2581 static void 2582 linkmap_delete(Obj_Entry *obj) 2583 { 2584 struct link_map *l = &obj->linkmap; 2585 2586 if (l->l_prev == NULL) { 2587 if ((r_debug.r_map = l->l_next) != NULL) 2588 l->l_next->l_prev = NULL; 2589 return; 2590 } 2591 2592 if ((l->l_prev->l_next = l->l_next) != NULL) 2593 l->l_next->l_prev = l->l_prev; 2594 } 2595 2596 /* 2597 * Function for the debugger to set a breakpoint on to gain control. 2598 * 2599 * The two parameters allow the debugger to easily find and determine 2600 * what the runtime loader is doing and to whom it is doing it. 2601 * 2602 * When the loadhook trap is hit (r_debug_state, set at program 2603 * initialization), the arguments can be found on the stack: 2604 * 2605 * +8 struct link_map *m 2606 * +4 struct r_debug *rd 2607 * +0 RetAddr 2608 */ 2609 void 2610 r_debug_state(struct r_debug* rd, struct link_map *m) 2611 { 2612 } 2613 2614 /* 2615 * Get address of the pointer variable in the main program. 2616 */ 2617 static const void ** 2618 get_program_var_addr(const char *name) 2619 { 2620 const Obj_Entry *obj; 2621 unsigned long hash; 2622 2623 hash = elf_hash(name); 2624 for (obj = obj_main; obj != NULL; obj = obj->next) { 2625 const Elf_Sym *def; 2626 2627 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2628 const void **addr; 2629 2630 addr = (const void **)(obj->relocbase + def->st_value); 2631 return addr; 2632 } 2633 } 2634 return NULL; 2635 } 2636 2637 /* 2638 * Set a pointer variable in the main program to the given value. This 2639 * is used to set key variables such as "environ" before any of the 2640 * init functions are called. 2641 */ 2642 static void 2643 set_program_var(const char *name, const void *value) 2644 { 2645 const void **addr; 2646 2647 if ((addr = get_program_var_addr(name)) != NULL) { 2648 dbg("\"%s\": *%p <-- %p", name, addr, value); 2649 *addr = value; 2650 } 2651 } 2652 2653 /* 2654 * Given a symbol name in a referencing object, find the corresponding 2655 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2656 * no definition was found. Returns a pointer to the Obj_Entry of the 2657 * defining object via the reference parameter DEFOBJ_OUT. 2658 */ 2659 static const Elf_Sym * 2660 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2661 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2662 { 2663 DoneList donelist; 2664 const Elf_Sym *def; 2665 const Elf_Sym *symp; 2666 const Obj_Entry *obj; 2667 const Obj_Entry *defobj; 2668 const Objlist_Entry *elm; 2669 def = NULL; 2670 defobj = NULL; 2671 donelist_init(&donelist); 2672 2673 /* Look first in the referencing object if linked symbolically. */ 2674 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2675 symp = symlook_obj(name, hash, refobj, ventry, flags); 2676 if (symp != NULL) { 2677 def = symp; 2678 defobj = refobj; 2679 } 2680 } 2681 2682 /* Search all objects loaded at program start up. */ 2683 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2684 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2685 &donelist); 2686 if (symp != NULL && 2687 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2688 def = symp; 2689 defobj = obj; 2690 } 2691 } 2692 2693 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2694 STAILQ_FOREACH(elm, &list_global, link) { 2695 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2696 break; 2697 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2698 flags, &donelist); 2699 if (symp != NULL && 2700 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2701 def = symp; 2702 defobj = obj; 2703 } 2704 } 2705 2706 /* Search all dlopened DAGs containing the referencing object. */ 2707 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2708 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2709 break; 2710 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2711 flags, &donelist); 2712 if (symp != NULL && 2713 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2714 def = symp; 2715 defobj = obj; 2716 } 2717 } 2718 2719 /* 2720 * Search the dynamic linker itself, and possibly resolve the 2721 * symbol from there. This is how the application links to 2722 * dynamic linker services such as dlopen. Only the values listed 2723 * in the "exports" array can be resolved from the dynamic linker. 2724 */ 2725 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2726 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2727 if (symp != NULL && is_exported(symp)) { 2728 def = symp; 2729 defobj = &obj_rtld; 2730 } 2731 } 2732 2733 if (def != NULL) 2734 *defobj_out = defobj; 2735 return def; 2736 } 2737 2738 static const Elf_Sym * 2739 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2740 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2741 DoneList *dlp) 2742 { 2743 const Elf_Sym *symp; 2744 const Elf_Sym *def; 2745 const Obj_Entry *defobj; 2746 const Objlist_Entry *elm; 2747 2748 def = NULL; 2749 defobj = NULL; 2750 STAILQ_FOREACH(elm, objlist, link) { 2751 if (donelist_check(dlp, elm->obj)) 2752 continue; 2753 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2754 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2755 def = symp; 2756 defobj = elm->obj; 2757 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2758 break; 2759 } 2760 } 2761 } 2762 if (def != NULL) 2763 *defobj_out = defobj; 2764 return def; 2765 } 2766 2767 /* 2768 * Search the symbol table of a shared object and all objects needed 2769 * by it for a symbol of the given name. Search order is 2770 * breadth-first. Returns a pointer to the symbol, or NULL if no 2771 * definition was found. 2772 */ 2773 static const Elf_Sym * 2774 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2775 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2776 DoneList *dlp) 2777 { 2778 const Elf_Sym *def, *def_w; 2779 const Needed_Entry *n; 2780 const Obj_Entry *obj, *defobj, *defobj1; 2781 2782 def = def_w = NULL; 2783 defobj = NULL; 2784 for (n = needed; n != NULL; n = n->next) { 2785 if ((obj = n->obj) == NULL || 2786 donelist_check(dlp, obj) || 2787 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2788 continue; 2789 defobj = obj; 2790 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2791 *defobj_out = defobj; 2792 return (def); 2793 } 2794 } 2795 /* 2796 * There we come when either symbol definition is not found in 2797 * directly needed objects, or found symbol is weak. 2798 */ 2799 for (n = needed; n != NULL; n = n->next) { 2800 if ((obj = n->obj) == NULL) 2801 continue; 2802 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2803 ventry, flags, dlp); 2804 if (def_w == NULL) 2805 continue; 2806 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2807 def = def_w; 2808 defobj = defobj1; 2809 } 2810 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2811 break; 2812 } 2813 if (def != NULL) 2814 *defobj_out = defobj; 2815 return (def); 2816 } 2817 2818 /* 2819 * Search the symbol table of a single shared object for a symbol of 2820 * the given name and version, if requested. Returns a pointer to the 2821 * symbol, or NULL if no definition was found. 2822 * 2823 * The symbol's hash value is passed in for efficiency reasons; that 2824 * eliminates many recomputations of the hash value. 2825 */ 2826 const Elf_Sym * 2827 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2828 const Ver_Entry *ventry, int flags) 2829 { 2830 unsigned long symnum; 2831 const Elf_Sym *vsymp; 2832 Elf_Versym verndx; 2833 int vcount; 2834 2835 if (obj->buckets == NULL) 2836 return NULL; 2837 2838 vsymp = NULL; 2839 vcount = 0; 2840 symnum = obj->buckets[hash % obj->nbuckets]; 2841 2842 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2843 const Elf_Sym *symp; 2844 const char *strp; 2845 2846 if (symnum >= obj->nchains) 2847 return NULL; /* Bad object */ 2848 2849 symp = obj->symtab + symnum; 2850 strp = obj->strtab + symp->st_name; 2851 2852 switch (ELF_ST_TYPE(symp->st_info)) { 2853 case STT_FUNC: 2854 case STT_NOTYPE: 2855 case STT_OBJECT: 2856 if (symp->st_value == 0) 2857 continue; 2858 /* fallthrough */ 2859 case STT_TLS: 2860 if (symp->st_shndx != SHN_UNDEF) 2861 break; 2862 #ifndef __mips__ 2863 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2864 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2865 break; 2866 /* fallthrough */ 2867 #endif 2868 default: 2869 continue; 2870 } 2871 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2872 continue; 2873 2874 if (ventry == NULL) { 2875 if (obj->versyms != NULL) { 2876 verndx = VER_NDX(obj->versyms[symnum]); 2877 if (verndx > obj->vernum) { 2878 _rtld_error("%s: symbol %s references wrong version %d", 2879 obj->path, obj->strtab + symnum, verndx); 2880 continue; 2881 } 2882 /* 2883 * If we are not called from dlsym (i.e. this is a normal 2884 * relocation from unversioned binary, accept the symbol 2885 * immediately if it happens to have first version after 2886 * this shared object became versioned. Otherwise, if 2887 * symbol is versioned and not hidden, remember it. If it 2888 * is the only symbol with this name exported by the 2889 * shared object, it will be returned as a match at the 2890 * end of the function. If symbol is global (verndx < 2) 2891 * accept it unconditionally. 2892 */ 2893 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2894 return symp; 2895 else if (verndx >= VER_NDX_GIVEN) { 2896 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2897 if (vsymp == NULL) 2898 vsymp = symp; 2899 vcount ++; 2900 } 2901 continue; 2902 } 2903 } 2904 return symp; 2905 } else { 2906 if (obj->versyms == NULL) { 2907 if (object_match_name(obj, ventry->name)) { 2908 _rtld_error("%s: object %s should provide version %s for " 2909 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2910 obj->strtab + symnum); 2911 continue; 2912 } 2913 } else { 2914 verndx = VER_NDX(obj->versyms[symnum]); 2915 if (verndx > obj->vernum) { 2916 _rtld_error("%s: symbol %s references wrong version %d", 2917 obj->path, obj->strtab + symnum, verndx); 2918 continue; 2919 } 2920 if (obj->vertab[verndx].hash != ventry->hash || 2921 strcmp(obj->vertab[verndx].name, ventry->name)) { 2922 /* 2923 * Version does not match. Look if this is a global symbol 2924 * and if it is not hidden. If global symbol (verndx < 2) 2925 * is available, use it. Do not return symbol if we are 2926 * called by dlvsym, because dlvsym looks for a specific 2927 * version and default one is not what dlvsym wants. 2928 */ 2929 if ((flags & SYMLOOK_DLSYM) || 2930 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2931 (verndx >= VER_NDX_GIVEN)) 2932 continue; 2933 } 2934 } 2935 return symp; 2936 } 2937 } 2938 return (vcount == 1) ? vsymp : NULL; 2939 } 2940 2941 static void 2942 trace_loaded_objects(Obj_Entry *obj) 2943 { 2944 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2945 int c; 2946 2947 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2948 main_local = ""; 2949 2950 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2951 fmt1 = "\t%o => %p (%x)\n"; 2952 2953 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2954 fmt2 = "\t%o (%x)\n"; 2955 2956 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2957 2958 for (; obj; obj = obj->next) { 2959 Needed_Entry *needed; 2960 char *name, *path; 2961 bool is_lib; 2962 2963 if (list_containers && obj->needed != NULL) 2964 printf("%s:\n", obj->path); 2965 for (needed = obj->needed; needed; needed = needed->next) { 2966 if (needed->obj != NULL) { 2967 if (needed->obj->traced && !list_containers) 2968 continue; 2969 needed->obj->traced = true; 2970 path = needed->obj->path; 2971 } else 2972 path = "not found"; 2973 2974 name = (char *)obj->strtab + needed->name; 2975 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2976 2977 fmt = is_lib ? fmt1 : fmt2; 2978 while ((c = *fmt++) != '\0') { 2979 switch (c) { 2980 default: 2981 putchar(c); 2982 continue; 2983 case '\\': 2984 switch (c = *fmt) { 2985 case '\0': 2986 continue; 2987 case 'n': 2988 putchar('\n'); 2989 break; 2990 case 't': 2991 putchar('\t'); 2992 break; 2993 } 2994 break; 2995 case '%': 2996 switch (c = *fmt) { 2997 case '\0': 2998 continue; 2999 case '%': 3000 default: 3001 putchar(c); 3002 break; 3003 case 'A': 3004 printf("%s", main_local); 3005 break; 3006 case 'a': 3007 printf("%s", obj_main->path); 3008 break; 3009 case 'o': 3010 printf("%s", name); 3011 break; 3012 #if 0 3013 case 'm': 3014 printf("%d", sodp->sod_major); 3015 break; 3016 case 'n': 3017 printf("%d", sodp->sod_minor); 3018 break; 3019 #endif 3020 case 'p': 3021 printf("%s", path); 3022 break; 3023 case 'x': 3024 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3025 break; 3026 } 3027 break; 3028 } 3029 ++fmt; 3030 } 3031 } 3032 } 3033 } 3034 3035 /* 3036 * Unload a dlopened object and its dependencies from memory and from 3037 * our data structures. It is assumed that the DAG rooted in the 3038 * object has already been unreferenced, and that the object has a 3039 * reference count of 0. 3040 */ 3041 static void 3042 unload_object(Obj_Entry *root) 3043 { 3044 Obj_Entry *obj; 3045 Obj_Entry **linkp; 3046 3047 assert(root->refcount == 0); 3048 3049 /* 3050 * Pass over the DAG removing unreferenced objects from 3051 * appropriate lists. 3052 */ 3053 unlink_object(root); 3054 3055 /* Unmap all objects that are no longer referenced. */ 3056 linkp = &obj_list->next; 3057 while ((obj = *linkp) != NULL) { 3058 if (obj->refcount == 0) { 3059 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3060 obj->path); 3061 dbg("unloading \"%s\"", obj->path); 3062 munmap(obj->mapbase, obj->mapsize); 3063 linkmap_delete(obj); 3064 *linkp = obj->next; 3065 obj_count--; 3066 obj_free(obj); 3067 } else 3068 linkp = &obj->next; 3069 } 3070 obj_tail = linkp; 3071 } 3072 3073 static void 3074 unlink_object(Obj_Entry *root) 3075 { 3076 Objlist_Entry *elm; 3077 3078 if (root->refcount == 0) { 3079 /* Remove the object from the RTLD_GLOBAL list. */ 3080 objlist_remove(&list_global, root); 3081 3082 /* Remove the object from all objects' DAG lists. */ 3083 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3084 objlist_remove(&elm->obj->dldags, root); 3085 if (elm->obj != root) 3086 unlink_object(elm->obj); 3087 } 3088 } 3089 } 3090 3091 static void 3092 ref_dag(Obj_Entry *root) 3093 { 3094 Objlist_Entry *elm; 3095 3096 STAILQ_FOREACH(elm, &root->dagmembers, link) 3097 elm->obj->refcount++; 3098 } 3099 3100 static void 3101 unref_dag(Obj_Entry *root) 3102 { 3103 Objlist_Entry *elm; 3104 3105 STAILQ_FOREACH(elm, &root->dagmembers, link) 3106 elm->obj->refcount--; 3107 } 3108 3109 /* 3110 * Common code for MD __tls_get_addr(). 3111 */ 3112 void * 3113 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3114 { 3115 Elf_Addr* dtv = *dtvp; 3116 int lockstate; 3117 3118 /* Check dtv generation in case new modules have arrived */ 3119 if (dtv[0] != tls_dtv_generation) { 3120 Elf_Addr* newdtv; 3121 int to_copy; 3122 3123 lockstate = wlock_acquire(rtld_bind_lock); 3124 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3125 to_copy = dtv[1]; 3126 if (to_copy > tls_max_index) 3127 to_copy = tls_max_index; 3128 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3129 newdtv[0] = tls_dtv_generation; 3130 newdtv[1] = tls_max_index; 3131 free(dtv); 3132 wlock_release(rtld_bind_lock, lockstate); 3133 *dtvp = newdtv; 3134 } 3135 3136 /* Dynamically allocate module TLS if necessary */ 3137 if (!dtv[index + 1]) { 3138 /* Signal safe, wlock will block out signals. */ 3139 lockstate = wlock_acquire(rtld_bind_lock); 3140 if (!dtv[index + 1]) 3141 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3142 wlock_release(rtld_bind_lock, lockstate); 3143 } 3144 return (void*) (dtv[index + 1] + offset); 3145 } 3146 3147 /* XXX not sure what variants to use for arm. */ 3148 3149 #if defined(__ia64__) || defined(__powerpc__) 3150 3151 /* 3152 * Allocate Static TLS using the Variant I method. 3153 */ 3154 void * 3155 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3156 { 3157 Obj_Entry *obj; 3158 char *tcb; 3159 Elf_Addr **tls; 3160 Elf_Addr *dtv; 3161 Elf_Addr addr; 3162 int i; 3163 3164 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3165 return (oldtcb); 3166 3167 assert(tcbsize >= TLS_TCB_SIZE); 3168 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3169 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3170 3171 if (oldtcb != NULL) { 3172 memcpy(tls, oldtcb, tls_static_space); 3173 free(oldtcb); 3174 3175 /* Adjust the DTV. */ 3176 dtv = tls[0]; 3177 for (i = 0; i < dtv[1]; i++) { 3178 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3179 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3180 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3181 } 3182 } 3183 } else { 3184 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3185 tls[0] = dtv; 3186 dtv[0] = tls_dtv_generation; 3187 dtv[1] = tls_max_index; 3188 3189 for (obj = objs; obj; obj = obj->next) { 3190 if (obj->tlsoffset > 0) { 3191 addr = (Elf_Addr)tls + obj->tlsoffset; 3192 if (obj->tlsinitsize > 0) 3193 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3194 if (obj->tlssize > obj->tlsinitsize) 3195 memset((void*) (addr + obj->tlsinitsize), 0, 3196 obj->tlssize - obj->tlsinitsize); 3197 dtv[obj->tlsindex + 1] = addr; 3198 } 3199 } 3200 } 3201 3202 return (tcb); 3203 } 3204 3205 void 3206 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3207 { 3208 Elf_Addr *dtv; 3209 Elf_Addr tlsstart, tlsend; 3210 int dtvsize, i; 3211 3212 assert(tcbsize >= TLS_TCB_SIZE); 3213 3214 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3215 tlsend = tlsstart + tls_static_space; 3216 3217 dtv = *(Elf_Addr **)tlsstart; 3218 dtvsize = dtv[1]; 3219 for (i = 0; i < dtvsize; i++) { 3220 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3221 free((void*)dtv[i+2]); 3222 } 3223 } 3224 free(dtv); 3225 free(tcb); 3226 } 3227 3228 #endif 3229 3230 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3231 defined(__arm__) || defined(__mips__) 3232 3233 /* 3234 * Allocate Static TLS using the Variant II method. 3235 */ 3236 void * 3237 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3238 { 3239 Obj_Entry *obj; 3240 size_t size; 3241 char *tls; 3242 Elf_Addr *dtv, *olddtv; 3243 Elf_Addr segbase, oldsegbase, addr; 3244 int i; 3245 3246 size = round(tls_static_space, tcbalign); 3247 3248 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3249 tls = calloc(1, size + tcbsize); 3250 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3251 3252 segbase = (Elf_Addr)(tls + size); 3253 ((Elf_Addr*)segbase)[0] = segbase; 3254 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3255 3256 dtv[0] = tls_dtv_generation; 3257 dtv[1] = tls_max_index; 3258 3259 if (oldtls) { 3260 /* 3261 * Copy the static TLS block over whole. 3262 */ 3263 oldsegbase = (Elf_Addr) oldtls; 3264 memcpy((void *)(segbase - tls_static_space), 3265 (const void *)(oldsegbase - tls_static_space), 3266 tls_static_space); 3267 3268 /* 3269 * If any dynamic TLS blocks have been created tls_get_addr(), 3270 * move them over. 3271 */ 3272 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3273 for (i = 0; i < olddtv[1]; i++) { 3274 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3275 dtv[i+2] = olddtv[i+2]; 3276 olddtv[i+2] = 0; 3277 } 3278 } 3279 3280 /* 3281 * We assume that this block was the one we created with 3282 * allocate_initial_tls(). 3283 */ 3284 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3285 } else { 3286 for (obj = objs; obj; obj = obj->next) { 3287 if (obj->tlsoffset) { 3288 addr = segbase - obj->tlsoffset; 3289 memset((void*) (addr + obj->tlsinitsize), 3290 0, obj->tlssize - obj->tlsinitsize); 3291 if (obj->tlsinit) 3292 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3293 dtv[obj->tlsindex + 1] = addr; 3294 } 3295 } 3296 } 3297 3298 return (void*) segbase; 3299 } 3300 3301 void 3302 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3303 { 3304 size_t size; 3305 Elf_Addr* dtv; 3306 int dtvsize, i; 3307 Elf_Addr tlsstart, tlsend; 3308 3309 /* 3310 * Figure out the size of the initial TLS block so that we can 3311 * find stuff which ___tls_get_addr() allocated dynamically. 3312 */ 3313 size = round(tls_static_space, tcbalign); 3314 3315 dtv = ((Elf_Addr**)tls)[1]; 3316 dtvsize = dtv[1]; 3317 tlsend = (Elf_Addr) tls; 3318 tlsstart = tlsend - size; 3319 for (i = 0; i < dtvsize; i++) { 3320 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3321 free((void*) dtv[i+2]); 3322 } 3323 } 3324 3325 free((void*) tlsstart); 3326 free((void*) dtv); 3327 } 3328 3329 #endif 3330 3331 /* 3332 * Allocate TLS block for module with given index. 3333 */ 3334 void * 3335 allocate_module_tls(int index) 3336 { 3337 Obj_Entry* obj; 3338 char* p; 3339 3340 for (obj = obj_list; obj; obj = obj->next) { 3341 if (obj->tlsindex == index) 3342 break; 3343 } 3344 if (!obj) { 3345 _rtld_error("Can't find module with TLS index %d", index); 3346 die(); 3347 } 3348 3349 p = malloc(obj->tlssize); 3350 if (p == NULL) { 3351 _rtld_error("Cannot allocate TLS block for index %d", index); 3352 die(); 3353 } 3354 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3355 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3356 3357 return p; 3358 } 3359 3360 bool 3361 allocate_tls_offset(Obj_Entry *obj) 3362 { 3363 size_t off; 3364 3365 if (obj->tls_done) 3366 return true; 3367 3368 if (obj->tlssize == 0) { 3369 obj->tls_done = true; 3370 return true; 3371 } 3372 3373 if (obj->tlsindex == 1) 3374 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3375 else 3376 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3377 obj->tlssize, obj->tlsalign); 3378 3379 /* 3380 * If we have already fixed the size of the static TLS block, we 3381 * must stay within that size. When allocating the static TLS, we 3382 * leave a small amount of space spare to be used for dynamically 3383 * loading modules which use static TLS. 3384 */ 3385 if (tls_static_space) { 3386 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3387 return false; 3388 } 3389 3390 tls_last_offset = obj->tlsoffset = off; 3391 tls_last_size = obj->tlssize; 3392 obj->tls_done = true; 3393 3394 return true; 3395 } 3396 3397 void 3398 free_tls_offset(Obj_Entry *obj) 3399 { 3400 3401 /* 3402 * If we were the last thing to allocate out of the static TLS 3403 * block, we give our space back to the 'allocator'. This is a 3404 * simplistic workaround to allow libGL.so.1 to be loaded and 3405 * unloaded multiple times. 3406 */ 3407 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3408 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3409 tls_last_offset -= obj->tlssize; 3410 tls_last_size = 0; 3411 } 3412 } 3413 3414 void * 3415 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3416 { 3417 void *ret; 3418 int lockstate; 3419 3420 lockstate = wlock_acquire(rtld_bind_lock); 3421 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3422 wlock_release(rtld_bind_lock, lockstate); 3423 return (ret); 3424 } 3425 3426 void 3427 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3428 { 3429 int lockstate; 3430 3431 lockstate = wlock_acquire(rtld_bind_lock); 3432 free_tls(tcb, tcbsize, tcbalign); 3433 wlock_release(rtld_bind_lock, lockstate); 3434 } 3435 3436 static void 3437 object_add_name(Obj_Entry *obj, const char *name) 3438 { 3439 Name_Entry *entry; 3440 size_t len; 3441 3442 len = strlen(name); 3443 entry = malloc(sizeof(Name_Entry) + len); 3444 3445 if (entry != NULL) { 3446 strcpy(entry->name, name); 3447 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3448 } 3449 } 3450 3451 static int 3452 object_match_name(const Obj_Entry *obj, const char *name) 3453 { 3454 Name_Entry *entry; 3455 3456 STAILQ_FOREACH(entry, &obj->names, link) { 3457 if (strcmp(name, entry->name) == 0) 3458 return (1); 3459 } 3460 return (0); 3461 } 3462 3463 static Obj_Entry * 3464 locate_dependency(const Obj_Entry *obj, const char *name) 3465 { 3466 const Objlist_Entry *entry; 3467 const Needed_Entry *needed; 3468 3469 STAILQ_FOREACH(entry, &list_main, link) { 3470 if (object_match_name(entry->obj, name)) 3471 return entry->obj; 3472 } 3473 3474 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3475 if (needed->obj == NULL) 3476 continue; 3477 if (object_match_name(needed->obj, name)) 3478 return needed->obj; 3479 } 3480 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3481 obj->path, name); 3482 die(); 3483 } 3484 3485 static int 3486 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3487 const Elf_Vernaux *vna) 3488 { 3489 const Elf_Verdef *vd; 3490 const char *vername; 3491 3492 vername = refobj->strtab + vna->vna_name; 3493 vd = depobj->verdef; 3494 if (vd == NULL) { 3495 _rtld_error("%s: version %s required by %s not defined", 3496 depobj->path, vername, refobj->path); 3497 return (-1); 3498 } 3499 for (;;) { 3500 if (vd->vd_version != VER_DEF_CURRENT) { 3501 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3502 depobj->path, vd->vd_version); 3503 return (-1); 3504 } 3505 if (vna->vna_hash == vd->vd_hash) { 3506 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3507 ((char *)vd + vd->vd_aux); 3508 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3509 return (0); 3510 } 3511 if (vd->vd_next == 0) 3512 break; 3513 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3514 } 3515 if (vna->vna_flags & VER_FLG_WEAK) 3516 return (0); 3517 _rtld_error("%s: version %s required by %s not found", 3518 depobj->path, vername, refobj->path); 3519 return (-1); 3520 } 3521 3522 static int 3523 rtld_verify_object_versions(Obj_Entry *obj) 3524 { 3525 const Elf_Verneed *vn; 3526 const Elf_Verdef *vd; 3527 const Elf_Verdaux *vda; 3528 const Elf_Vernaux *vna; 3529 const Obj_Entry *depobj; 3530 int maxvernum, vernum; 3531 3532 maxvernum = 0; 3533 /* 3534 * Walk over defined and required version records and figure out 3535 * max index used by any of them. Do very basic sanity checking 3536 * while there. 3537 */ 3538 vn = obj->verneed; 3539 while (vn != NULL) { 3540 if (vn->vn_version != VER_NEED_CURRENT) { 3541 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3542 obj->path, vn->vn_version); 3543 return (-1); 3544 } 3545 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3546 for (;;) { 3547 vernum = VER_NEED_IDX(vna->vna_other); 3548 if (vernum > maxvernum) 3549 maxvernum = vernum; 3550 if (vna->vna_next == 0) 3551 break; 3552 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3553 } 3554 if (vn->vn_next == 0) 3555 break; 3556 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3557 } 3558 3559 vd = obj->verdef; 3560 while (vd != NULL) { 3561 if (vd->vd_version != VER_DEF_CURRENT) { 3562 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3563 obj->path, vd->vd_version); 3564 return (-1); 3565 } 3566 vernum = VER_DEF_IDX(vd->vd_ndx); 3567 if (vernum > maxvernum) 3568 maxvernum = vernum; 3569 if (vd->vd_next == 0) 3570 break; 3571 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3572 } 3573 3574 if (maxvernum == 0) 3575 return (0); 3576 3577 /* 3578 * Store version information in array indexable by version index. 3579 * Verify that object version requirements are satisfied along the 3580 * way. 3581 */ 3582 obj->vernum = maxvernum + 1; 3583 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3584 3585 vd = obj->verdef; 3586 while (vd != NULL) { 3587 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3588 vernum = VER_DEF_IDX(vd->vd_ndx); 3589 assert(vernum <= maxvernum); 3590 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3591 obj->vertab[vernum].hash = vd->vd_hash; 3592 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3593 obj->vertab[vernum].file = NULL; 3594 obj->vertab[vernum].flags = 0; 3595 } 3596 if (vd->vd_next == 0) 3597 break; 3598 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3599 } 3600 3601 vn = obj->verneed; 3602 while (vn != NULL) { 3603 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3604 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3605 for (;;) { 3606 if (check_object_provided_version(obj, depobj, vna)) 3607 return (-1); 3608 vernum = VER_NEED_IDX(vna->vna_other); 3609 assert(vernum <= maxvernum); 3610 obj->vertab[vernum].hash = vna->vna_hash; 3611 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3612 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3613 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3614 VER_INFO_HIDDEN : 0; 3615 if (vna->vna_next == 0) 3616 break; 3617 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3618 } 3619 if (vn->vn_next == 0) 3620 break; 3621 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3622 } 3623 return 0; 3624 } 3625 3626 static int 3627 rtld_verify_versions(const Objlist *objlist) 3628 { 3629 Objlist_Entry *entry; 3630 int rc; 3631 3632 rc = 0; 3633 STAILQ_FOREACH(entry, objlist, link) { 3634 /* 3635 * Skip dummy objects or objects that have their version requirements 3636 * already checked. 3637 */ 3638 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3639 continue; 3640 if (rtld_verify_object_versions(entry->obj) == -1) { 3641 rc = -1; 3642 if (ld_tracing == NULL) 3643 break; 3644 } 3645 } 3646 if (rc == 0 || ld_tracing != NULL) 3647 rc = rtld_verify_object_versions(&obj_rtld); 3648 return rc; 3649 } 3650 3651 const Ver_Entry * 3652 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3653 { 3654 Elf_Versym vernum; 3655 3656 if (obj->vertab) { 3657 vernum = VER_NDX(obj->versyms[symnum]); 3658 if (vernum >= obj->vernum) { 3659 _rtld_error("%s: symbol %s has wrong verneed value %d", 3660 obj->path, obj->strtab + symnum, vernum); 3661 } else if (obj->vertab[vernum].hash != 0) { 3662 return &obj->vertab[vernum]; 3663 } 3664 } 3665 return NULL; 3666 } 3667 3668 int 3669 __getosreldate(void) 3670 { 3671 size_t len; 3672 int oid[2]; 3673 int error, osrel; 3674 3675 if (osreldate != 0) 3676 return (osreldate); 3677 3678 oid[0] = CTL_KERN; 3679 oid[1] = KERN_OSRELDATE; 3680 osrel = 0; 3681 len = sizeof(osrel); 3682 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 3683 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 3684 osreldate = osrel; 3685 return (osreldate); 3686 } 3687