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/uio.h> 44 #include <sys/utsname.h> 45 #include <sys/ktrace.h> 46 47 #include <dlfcn.h> 48 #include <err.h> 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <stdarg.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 #include "debug.h" 58 #include "rtld.h" 59 #include "libmap.h" 60 #include "rtld_tls.h" 61 62 #ifndef COMPAT_32BIT 63 #define PATH_RTLD "/libexec/ld-elf.so.1" 64 #else 65 #define PATH_RTLD "/libexec/ld-elf32.so.1" 66 #endif 67 68 /* Types. */ 69 typedef void (*func_ptr_type)(); 70 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 71 72 /* 73 * This structure provides a reentrant way to keep a list of objects and 74 * check which ones have already been processed in some way. 75 */ 76 typedef struct Struct_DoneList { 77 const Obj_Entry **objs; /* Array of object pointers */ 78 unsigned int num_alloc; /* Allocated size of the array */ 79 unsigned int num_used; /* Number of array slots used */ 80 } DoneList; 81 82 /* 83 * Function declarations. 84 */ 85 static const char *basename(const char *); 86 static void die(void) __dead2; 87 static void digest_dynamic(Obj_Entry *, int); 88 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 89 static Obj_Entry *dlcheck(void *); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *); 97 static const char *gethints(void); 98 static void init_dag(Obj_Entry *); 99 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 100 static void init_rtld(caddr_t); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static bool is_exported(const Elf_Sym *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static int load_needed_objects(Obj_Entry *, int); 107 static int load_preload_objects(void); 108 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 109 static Obj_Entry *obj_from_addr(const void *); 110 static void objlist_call_fini(Objlist *, bool, int *); 111 static void objlist_call_init(Objlist *, int *); 112 static void objlist_clear(Objlist *); 113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114 static void objlist_init(Objlist *); 115 static void objlist_push_head(Objlist *, Obj_Entry *); 116 static void objlist_push_tail(Objlist *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 120 static int rtld_dirname(const char *, char *); 121 static int rtld_dirname_abs(const char *, char *); 122 static void rtld_exit(void); 123 static char *search_library_path(const char *, const char *); 124 static const void **get_program_var_addr(const char *); 125 static void set_program_var(const char *, const void *); 126 static const Elf_Sym *symlook_default(const char *, unsigned long, 127 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 128 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 129 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 130 static const Elf_Sym *symlook_needed(const char *, unsigned long, 131 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 132 int, DoneList *); 133 static void trace_loaded_objects(Obj_Entry *); 134 static void unlink_object(Obj_Entry *); 135 static void unload_object(Obj_Entry *); 136 static void unref_dag(Obj_Entry *); 137 static void ref_dag(Obj_Entry *); 138 static int origin_subst_one(char **, const char *, const char *, 139 const char *, char *); 140 static char *origin_subst(const char *, const char *); 141 static int rtld_verify_versions(const Objlist *); 142 static int rtld_verify_object_versions(Obj_Entry *); 143 static void object_add_name(Obj_Entry *, const char *); 144 static int object_match_name(const Obj_Entry *, const char *); 145 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 146 147 void r_debug_state(struct r_debug *, struct link_map *); 148 149 /* 150 * Data declarations. 151 */ 152 static char *error_message; /* Message for dlerror(), or NULL */ 153 struct r_debug r_debug; /* for GDB; */ 154 static bool libmap_disable; /* Disable libmap */ 155 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 156 static bool trust; /* False for setuid and setgid programs */ 157 static bool dangerous_ld_env; /* True if environment variables have been 158 used to affect the libraries loaded */ 159 static char *ld_bind_now; /* Environment variable for immediate binding */ 160 static char *ld_debug; /* Environment variable for debugging */ 161 static char *ld_library_path; /* Environment variable for search path */ 162 static char *ld_preload; /* Environment variable for libraries to 163 load first */ 164 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 165 static char *ld_tracing; /* Called from ldd to print libs */ 166 static char *ld_utrace; /* Use utrace() to log events. */ 167 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 168 static Obj_Entry **obj_tail; /* Link field of last object in list */ 169 static Obj_Entry *obj_main; /* The main program shared object */ 170 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 171 static unsigned int obj_count; /* Number of objects in obj_list */ 172 static unsigned int obj_loads; /* Number of objects in obj_list */ 173 174 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 175 STAILQ_HEAD_INITIALIZER(list_global); 176 static Objlist list_main = /* Objects loaded at program startup */ 177 STAILQ_HEAD_INITIALIZER(list_main); 178 static Objlist list_fini = /* Objects needing fini() calls */ 179 STAILQ_HEAD_INITIALIZER(list_fini); 180 181 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 182 183 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 184 185 extern Elf_Dyn _DYNAMIC; 186 #pragma weak _DYNAMIC 187 #ifndef RTLD_IS_DYNAMIC 188 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 189 #endif 190 191 /* 192 * These are the functions the dynamic linker exports to application 193 * programs. They are the only symbols the dynamic linker is willing 194 * to export from itself. 195 */ 196 static func_ptr_type exports[] = { 197 (func_ptr_type) &_rtld_error, 198 (func_ptr_type) &dlclose, 199 (func_ptr_type) &dlerror, 200 (func_ptr_type) &dlopen, 201 (func_ptr_type) &dlsym, 202 (func_ptr_type) &dlfunc, 203 (func_ptr_type) &dlvsym, 204 (func_ptr_type) &dladdr, 205 (func_ptr_type) &dllockinit, 206 (func_ptr_type) &dlinfo, 207 (func_ptr_type) &_rtld_thread_init, 208 #ifdef __i386__ 209 (func_ptr_type) &___tls_get_addr, 210 #endif 211 (func_ptr_type) &__tls_get_addr, 212 (func_ptr_type) &_rtld_allocate_tls, 213 (func_ptr_type) &_rtld_free_tls, 214 (func_ptr_type) &dl_iterate_phdr, 215 (func_ptr_type) &_rtld_atfork_pre, 216 (func_ptr_type) &_rtld_atfork_post, 217 NULL 218 }; 219 220 /* 221 * Global declarations normally provided by crt1. The dynamic linker is 222 * not built with crt1, so we have to provide them ourselves. 223 */ 224 char *__progname; 225 char **environ; 226 227 /* 228 * Globals to control TLS allocation. 229 */ 230 size_t tls_last_offset; /* Static TLS offset of last module */ 231 size_t tls_last_size; /* Static TLS size of last module */ 232 size_t tls_static_space; /* Static TLS space allocated */ 233 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 234 int tls_max_index = 1; /* Largest module index allocated */ 235 236 /* 237 * Fill in a DoneList with an allocation large enough to hold all of 238 * the currently-loaded objects. Keep this as a macro since it calls 239 * alloca and we want that to occur within the scope of the caller. 240 */ 241 #define donelist_init(dlp) \ 242 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 243 assert((dlp)->objs != NULL), \ 244 (dlp)->num_alloc = obj_count, \ 245 (dlp)->num_used = 0) 246 247 #define UTRACE_DLOPEN_START 1 248 #define UTRACE_DLOPEN_STOP 2 249 #define UTRACE_DLCLOSE_START 3 250 #define UTRACE_DLCLOSE_STOP 4 251 #define UTRACE_LOAD_OBJECT 5 252 #define UTRACE_UNLOAD_OBJECT 6 253 #define UTRACE_ADD_RUNDEP 7 254 #define UTRACE_PRELOAD_FINISHED 8 255 #define UTRACE_INIT_CALL 9 256 #define UTRACE_FINI_CALL 10 257 258 struct utrace_rtld { 259 char sig[4]; /* 'RTLD' */ 260 int event; 261 void *handle; 262 void *mapbase; /* Used for 'parent' and 'init/fini' */ 263 size_t mapsize; 264 int refcnt; /* Used for 'mode' */ 265 char name[MAXPATHLEN]; 266 }; 267 268 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 269 if (ld_utrace != NULL) \ 270 ld_utrace_log(e, h, mb, ms, r, n); \ 271 } while (0) 272 273 static void 274 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 275 int refcnt, const char *name) 276 { 277 struct utrace_rtld ut; 278 279 ut.sig[0] = 'R'; 280 ut.sig[1] = 'T'; 281 ut.sig[2] = 'L'; 282 ut.sig[3] = 'D'; 283 ut.event = event; 284 ut.handle = handle; 285 ut.mapbase = mapbase; 286 ut.mapsize = mapsize; 287 ut.refcnt = refcnt; 288 bzero(ut.name, sizeof(ut.name)); 289 if (name) 290 strlcpy(ut.name, name, sizeof(ut.name)); 291 utrace(&ut, sizeof(ut)); 292 } 293 294 /* 295 * Main entry point for dynamic linking. The first argument is the 296 * stack pointer. The stack is expected to be laid out as described 297 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 298 * Specifically, the stack pointer points to a word containing 299 * ARGC. Following that in the stack is a null-terminated sequence 300 * of pointers to argument strings. Then comes a null-terminated 301 * sequence of pointers to environment strings. Finally, there is a 302 * sequence of "auxiliary vector" entries. 303 * 304 * The second argument points to a place to store the dynamic linker's 305 * exit procedure pointer and the third to a place to store the main 306 * program's object. 307 * 308 * The return value is the main program's entry point. 309 */ 310 func_ptr_type 311 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 312 { 313 Elf_Auxinfo *aux_info[AT_COUNT]; 314 int i; 315 int argc; 316 char **argv; 317 char **env; 318 Elf_Auxinfo *aux; 319 Elf_Auxinfo *auxp; 320 const char *argv0; 321 Objlist_Entry *entry; 322 Obj_Entry *obj; 323 Obj_Entry **preload_tail; 324 Objlist initlist; 325 int lockstate; 326 327 /* 328 * On entry, the dynamic linker itself has not been relocated yet. 329 * Be very careful not to reference any global data until after 330 * init_rtld has returned. It is OK to reference file-scope statics 331 * and string constants, and to call static and global functions. 332 */ 333 334 /* Find the auxiliary vector on the stack. */ 335 argc = *sp++; 336 argv = (char **) sp; 337 sp += argc + 1; /* Skip over arguments and NULL terminator */ 338 env = (char **) sp; 339 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 340 ; 341 aux = (Elf_Auxinfo *) sp; 342 343 /* Digest the auxiliary vector. */ 344 for (i = 0; i < AT_COUNT; i++) 345 aux_info[i] = NULL; 346 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 347 if (auxp->a_type < AT_COUNT) 348 aux_info[auxp->a_type] = auxp; 349 } 350 351 /* Initialize and relocate ourselves. */ 352 assert(aux_info[AT_BASE] != NULL); 353 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 354 355 __progname = obj_rtld.path; 356 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 357 environ = env; 358 359 trust = !issetugid(); 360 361 ld_bind_now = getenv(LD_ "BIND_NOW"); 362 /* 363 * If the process is tainted, then we un-set the dangerous environment 364 * variables. The process will be marked as tainted until setuid(2) 365 * is called. If any child process calls setuid(2) we do not want any 366 * future processes to honor the potentially un-safe variables. 367 */ 368 if (!trust) { 369 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 370 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 371 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH")) { 372 _rtld_error("environment corrupt; aborting"); 373 die(); 374 } 375 } 376 ld_debug = getenv(LD_ "DEBUG"); 377 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 378 libmap_override = getenv(LD_ "LIBMAP"); 379 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 380 ld_preload = getenv(LD_ "PRELOAD"); 381 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 382 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 383 (ld_library_path != NULL) || (ld_preload != NULL) || 384 (ld_elf_hints_path != NULL); 385 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 386 ld_utrace = getenv(LD_ "UTRACE"); 387 388 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 389 ld_elf_hints_path = _PATH_ELF_HINTS; 390 391 if (ld_debug != NULL && *ld_debug != '\0') 392 debug = 1; 393 dbg("%s is initialized, base address = %p", __progname, 394 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 395 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 396 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 397 398 /* 399 * Load the main program, or process its program header if it is 400 * already loaded. 401 */ 402 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 403 int fd = aux_info[AT_EXECFD]->a_un.a_val; 404 dbg("loading main program"); 405 obj_main = map_object(fd, argv0, NULL); 406 close(fd); 407 if (obj_main == NULL) 408 die(); 409 } else { /* Main program already loaded. */ 410 const Elf_Phdr *phdr; 411 int phnum; 412 caddr_t entry; 413 414 dbg("processing main program's program header"); 415 assert(aux_info[AT_PHDR] != NULL); 416 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 417 assert(aux_info[AT_PHNUM] != NULL); 418 phnum = aux_info[AT_PHNUM]->a_un.a_val; 419 assert(aux_info[AT_PHENT] != NULL); 420 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 421 assert(aux_info[AT_ENTRY] != NULL); 422 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 423 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 424 die(); 425 } 426 427 if (aux_info[AT_EXECPATH] != 0) { 428 char *kexecpath; 429 char buf[MAXPATHLEN]; 430 431 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 432 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 433 if (kexecpath[0] == '/') 434 obj_main->path = kexecpath; 435 else if (getcwd(buf, sizeof(buf)) == NULL || 436 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 437 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 438 obj_main->path = xstrdup(argv0); 439 else 440 obj_main->path = xstrdup(buf); 441 } else { 442 dbg("No AT_EXECPATH"); 443 obj_main->path = xstrdup(argv0); 444 } 445 dbg("obj_main path %s", obj_main->path); 446 obj_main->mainprog = true; 447 448 /* 449 * Get the actual dynamic linker pathname from the executable if 450 * possible. (It should always be possible.) That ensures that 451 * gdb will find the right dynamic linker even if a non-standard 452 * one is being used. 453 */ 454 if (obj_main->interp != NULL && 455 strcmp(obj_main->interp, obj_rtld.path) != 0) { 456 free(obj_rtld.path); 457 obj_rtld.path = xstrdup(obj_main->interp); 458 __progname = obj_rtld.path; 459 } 460 461 digest_dynamic(obj_main, 0); 462 463 linkmap_add(obj_main); 464 linkmap_add(&obj_rtld); 465 466 /* Link the main program into the list of objects. */ 467 *obj_tail = obj_main; 468 obj_tail = &obj_main->next; 469 obj_count++; 470 obj_loads++; 471 /* Make sure we don't call the main program's init and fini functions. */ 472 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 473 474 /* Initialize a fake symbol for resolving undefined weak references. */ 475 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 476 sym_zero.st_shndx = SHN_UNDEF; 477 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 478 479 if (!libmap_disable) 480 libmap_disable = (bool)lm_init(libmap_override); 481 482 dbg("loading LD_PRELOAD libraries"); 483 if (load_preload_objects() == -1) 484 die(); 485 preload_tail = obj_tail; 486 487 dbg("loading needed objects"); 488 if (load_needed_objects(obj_main, 0) == -1) 489 die(); 490 491 /* Make a list of all objects loaded at startup. */ 492 for (obj = obj_list; obj != NULL; obj = obj->next) { 493 objlist_push_tail(&list_main, obj); 494 obj->refcount++; 495 } 496 497 dbg("checking for required versions"); 498 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 499 die(); 500 501 if (ld_tracing) { /* We're done */ 502 trace_loaded_objects(obj_main); 503 exit(0); 504 } 505 506 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 507 dump_relocations(obj_main); 508 exit (0); 509 } 510 511 /* setup TLS for main thread */ 512 dbg("initializing initial thread local storage"); 513 STAILQ_FOREACH(entry, &list_main, link) { 514 /* 515 * Allocate all the initial objects out of the static TLS 516 * block even if they didn't ask for it. 517 */ 518 allocate_tls_offset(entry->obj); 519 } 520 allocate_initial_tls(obj_list); 521 522 if (relocate_objects(obj_main, 523 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 524 die(); 525 526 dbg("doing copy relocations"); 527 if (do_copy_relocations(obj_main) == -1) 528 die(); 529 530 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 531 dump_relocations(obj_main); 532 exit (0); 533 } 534 535 dbg("initializing key program variables"); 536 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 537 set_program_var("environ", env); 538 539 dbg("initializing thread locks"); 540 lockdflt_init(); 541 542 /* Make a list of init functions to call. */ 543 objlist_init(&initlist); 544 initlist_add_objects(obj_list, preload_tail, &initlist); 545 546 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 547 548 lockstate = wlock_acquire(rtld_bind_lock); 549 objlist_call_init(&initlist, &lockstate); 550 objlist_clear(&initlist); 551 wlock_release(rtld_bind_lock, lockstate); 552 553 dbg("transferring control to program entry point = %p", obj_main->entry); 554 555 /* Return the exit procedure and the program entry point. */ 556 *exit_proc = rtld_exit; 557 *objp = obj_main; 558 return (func_ptr_type) obj_main->entry; 559 } 560 561 Elf_Addr 562 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 563 { 564 const Elf_Rel *rel; 565 const Elf_Sym *def; 566 const Obj_Entry *defobj; 567 Elf_Addr *where; 568 Elf_Addr target; 569 int lockstate; 570 571 lockstate = rlock_acquire(rtld_bind_lock); 572 if (obj->pltrel) 573 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 574 else 575 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 576 577 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 578 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 579 if (def == NULL) 580 die(); 581 582 target = (Elf_Addr)(defobj->relocbase + def->st_value); 583 584 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 585 defobj->strtab + def->st_name, basename(obj->path), 586 (void *)target, basename(defobj->path)); 587 588 /* 589 * Write the new contents for the jmpslot. Note that depending on 590 * architecture, the value which we need to return back to the 591 * lazy binding trampoline may or may not be the target 592 * address. The value returned from reloc_jmpslot() is the value 593 * that the trampoline needs. 594 */ 595 target = reloc_jmpslot(where, target, defobj, obj, rel); 596 rlock_release(rtld_bind_lock, lockstate); 597 return target; 598 } 599 600 /* 601 * Error reporting function. Use it like printf. If formats the message 602 * into a buffer, and sets things up so that the next call to dlerror() 603 * will return the message. 604 */ 605 void 606 _rtld_error(const char *fmt, ...) 607 { 608 static char buf[512]; 609 va_list ap; 610 611 va_start(ap, fmt); 612 vsnprintf(buf, sizeof buf, fmt, ap); 613 error_message = buf; 614 va_end(ap); 615 } 616 617 /* 618 * Return a dynamically-allocated copy of the current error message, if any. 619 */ 620 static char * 621 errmsg_save(void) 622 { 623 return error_message == NULL ? NULL : xstrdup(error_message); 624 } 625 626 /* 627 * Restore the current error message from a copy which was previously saved 628 * by errmsg_save(). The copy is freed. 629 */ 630 static void 631 errmsg_restore(char *saved_msg) 632 { 633 if (saved_msg == NULL) 634 error_message = NULL; 635 else { 636 _rtld_error("%s", saved_msg); 637 free(saved_msg); 638 } 639 } 640 641 static const char * 642 basename(const char *name) 643 { 644 const char *p = strrchr(name, '/'); 645 return p != NULL ? p + 1 : name; 646 } 647 648 static struct utsname uts; 649 650 static int 651 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 652 char *may_free) 653 { 654 const char *p, *p1; 655 char *res1; 656 int subst_len; 657 int kw_len; 658 659 res1 = *res = NULL; 660 p = real; 661 subst_len = kw_len = 0; 662 for (;;) { 663 p1 = strstr(p, kw); 664 if (p1 != NULL) { 665 if (subst_len == 0) { 666 subst_len = strlen(subst); 667 kw_len = strlen(kw); 668 } 669 if (*res == NULL) { 670 *res = xmalloc(PATH_MAX); 671 res1 = *res; 672 } 673 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 674 _rtld_error("Substitution of %s in %s cannot be performed", 675 kw, real); 676 if (may_free != NULL) 677 free(may_free); 678 free(res); 679 return (false); 680 } 681 memcpy(res1, p, p1 - p); 682 res1 += p1 - p; 683 memcpy(res1, subst, subst_len); 684 res1 += subst_len; 685 p = p1 + kw_len; 686 } else { 687 if (*res == NULL) { 688 if (may_free != NULL) 689 *res = may_free; 690 else 691 *res = xstrdup(real); 692 return (true); 693 } 694 *res1 = '\0'; 695 if (may_free != NULL) 696 free(may_free); 697 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 698 free(res); 699 return (false); 700 } 701 return (true); 702 } 703 } 704 } 705 706 static char * 707 origin_subst(const char *real, const char *origin_path) 708 { 709 char *res1, *res2, *res3, *res4; 710 711 if (uts.sysname[0] == '\0') { 712 if (uname(&uts) != 0) { 713 _rtld_error("utsname failed: %d", errno); 714 return (NULL); 715 } 716 } 717 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 718 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 719 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 720 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 721 return (NULL); 722 return (res4); 723 } 724 725 static void 726 die(void) 727 { 728 const char *msg = dlerror(); 729 730 if (msg == NULL) 731 msg = "Fatal error"; 732 errx(1, "%s", msg); 733 } 734 735 /* 736 * Process a shared object's DYNAMIC section, and save the important 737 * information in its Obj_Entry structure. 738 */ 739 static void 740 digest_dynamic(Obj_Entry *obj, int early) 741 { 742 const Elf_Dyn *dynp; 743 Needed_Entry **needed_tail = &obj->needed; 744 const Elf_Dyn *dyn_rpath = NULL; 745 const Elf_Dyn *dyn_soname = NULL; 746 int plttype = DT_REL; 747 748 obj->bind_now = false; 749 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 750 switch (dynp->d_tag) { 751 752 case DT_REL: 753 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 754 break; 755 756 case DT_RELSZ: 757 obj->relsize = dynp->d_un.d_val; 758 break; 759 760 case DT_RELENT: 761 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 762 break; 763 764 case DT_JMPREL: 765 obj->pltrel = (const Elf_Rel *) 766 (obj->relocbase + dynp->d_un.d_ptr); 767 break; 768 769 case DT_PLTRELSZ: 770 obj->pltrelsize = dynp->d_un.d_val; 771 break; 772 773 case DT_RELA: 774 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 775 break; 776 777 case DT_RELASZ: 778 obj->relasize = dynp->d_un.d_val; 779 break; 780 781 case DT_RELAENT: 782 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 783 break; 784 785 case DT_PLTREL: 786 plttype = dynp->d_un.d_val; 787 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 788 break; 789 790 case DT_SYMTAB: 791 obj->symtab = (const Elf_Sym *) 792 (obj->relocbase + dynp->d_un.d_ptr); 793 break; 794 795 case DT_SYMENT: 796 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 797 break; 798 799 case DT_STRTAB: 800 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 801 break; 802 803 case DT_STRSZ: 804 obj->strsize = dynp->d_un.d_val; 805 break; 806 807 case DT_VERNEED: 808 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 809 dynp->d_un.d_val); 810 break; 811 812 case DT_VERNEEDNUM: 813 obj->verneednum = dynp->d_un.d_val; 814 break; 815 816 case DT_VERDEF: 817 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 818 dynp->d_un.d_val); 819 break; 820 821 case DT_VERDEFNUM: 822 obj->verdefnum = dynp->d_un.d_val; 823 break; 824 825 case DT_VERSYM: 826 obj->versyms = (const Elf_Versym *)(obj->relocbase + 827 dynp->d_un.d_val); 828 break; 829 830 case DT_HASH: 831 { 832 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 833 (obj->relocbase + dynp->d_un.d_ptr); 834 obj->nbuckets = hashtab[0]; 835 obj->nchains = hashtab[1]; 836 obj->buckets = hashtab + 2; 837 obj->chains = obj->buckets + obj->nbuckets; 838 } 839 break; 840 841 case DT_NEEDED: 842 if (!obj->rtld) { 843 Needed_Entry *nep = NEW(Needed_Entry); 844 nep->name = dynp->d_un.d_val; 845 nep->obj = NULL; 846 nep->next = NULL; 847 848 *needed_tail = nep; 849 needed_tail = &nep->next; 850 } 851 break; 852 853 case DT_PLTGOT: 854 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 855 break; 856 857 case DT_TEXTREL: 858 obj->textrel = true; 859 break; 860 861 case DT_SYMBOLIC: 862 obj->symbolic = true; 863 break; 864 865 case DT_RPATH: 866 case DT_RUNPATH: /* XXX: process separately */ 867 /* 868 * We have to wait until later to process this, because we 869 * might not have gotten the address of the string table yet. 870 */ 871 dyn_rpath = dynp; 872 break; 873 874 case DT_SONAME: 875 dyn_soname = dynp; 876 break; 877 878 case DT_INIT: 879 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 880 break; 881 882 case DT_FINI: 883 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 884 break; 885 886 /* 887 * Don't process DT_DEBUG on MIPS as the dynamic section 888 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 889 */ 890 891 #ifndef __mips__ 892 case DT_DEBUG: 893 /* XXX - not implemented yet */ 894 if (!early) 895 dbg("Filling in DT_DEBUG entry"); 896 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 897 break; 898 #endif 899 900 case DT_FLAGS: 901 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 902 obj->z_origin = true; 903 if (dynp->d_un.d_val & DF_SYMBOLIC) 904 obj->symbolic = true; 905 if (dynp->d_un.d_val & DF_TEXTREL) 906 obj->textrel = true; 907 if (dynp->d_un.d_val & DF_BIND_NOW) 908 obj->bind_now = true; 909 if (dynp->d_un.d_val & DF_STATIC_TLS) 910 ; 911 break; 912 #ifdef __mips__ 913 case DT_MIPS_LOCAL_GOTNO: 914 obj->local_gotno = dynp->d_un.d_val; 915 break; 916 917 case DT_MIPS_SYMTABNO: 918 obj->symtabno = dynp->d_un.d_val; 919 break; 920 921 case DT_MIPS_GOTSYM: 922 obj->gotsym = dynp->d_un.d_val; 923 break; 924 925 case DT_MIPS_RLD_MAP: 926 #ifdef notyet 927 if (!early) 928 dbg("Filling in DT_DEBUG entry"); 929 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 930 #endif 931 break; 932 #endif 933 934 case DT_FLAGS_1: 935 if (dynp->d_un.d_val & DF_1_NOOPEN) 936 obj->z_noopen = true; 937 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 938 obj->z_origin = true; 939 if (dynp->d_un.d_val & DF_1_GLOBAL) 940 /* XXX */; 941 if (dynp->d_un.d_val & DF_1_BIND_NOW) 942 obj->bind_now = true; 943 if (dynp->d_un.d_val & DF_1_NODELETE) 944 obj->z_nodelete = true; 945 break; 946 947 default: 948 if (!early) { 949 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 950 (long)dynp->d_tag); 951 } 952 break; 953 } 954 } 955 956 obj->traced = false; 957 958 if (plttype == DT_RELA) { 959 obj->pltrela = (const Elf_Rela *) obj->pltrel; 960 obj->pltrel = NULL; 961 obj->pltrelasize = obj->pltrelsize; 962 obj->pltrelsize = 0; 963 } 964 965 if (obj->z_origin && obj->origin_path == NULL) { 966 obj->origin_path = xmalloc(PATH_MAX); 967 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 968 die(); 969 } 970 971 if (dyn_rpath != NULL) { 972 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 973 if (obj->z_origin) 974 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 975 } 976 977 if (dyn_soname != NULL) 978 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 979 } 980 981 /* 982 * Process a shared object's program header. This is used only for the 983 * main program, when the kernel has already loaded the main program 984 * into memory before calling the dynamic linker. It creates and 985 * returns an Obj_Entry structure. 986 */ 987 static Obj_Entry * 988 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 989 { 990 Obj_Entry *obj; 991 const Elf_Phdr *phlimit = phdr + phnum; 992 const Elf_Phdr *ph; 993 int nsegs = 0; 994 995 obj = obj_new(); 996 for (ph = phdr; ph < phlimit; ph++) { 997 if (ph->p_type != PT_PHDR) 998 continue; 999 1000 obj->phdr = phdr; 1001 obj->phsize = ph->p_memsz; 1002 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1003 break; 1004 } 1005 1006 for (ph = phdr; ph < phlimit; ph++) { 1007 switch (ph->p_type) { 1008 1009 case PT_INTERP: 1010 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1011 break; 1012 1013 case PT_LOAD: 1014 if (nsegs == 0) { /* First load segment */ 1015 obj->vaddrbase = trunc_page(ph->p_vaddr); 1016 obj->mapbase = obj->vaddrbase + obj->relocbase; 1017 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1018 obj->vaddrbase; 1019 } else { /* Last load segment */ 1020 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1021 obj->vaddrbase; 1022 } 1023 nsegs++; 1024 break; 1025 1026 case PT_DYNAMIC: 1027 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1028 break; 1029 1030 case PT_TLS: 1031 obj->tlsindex = 1; 1032 obj->tlssize = ph->p_memsz; 1033 obj->tlsalign = ph->p_align; 1034 obj->tlsinitsize = ph->p_filesz; 1035 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1036 break; 1037 } 1038 } 1039 if (nsegs < 1) { 1040 _rtld_error("%s: too few PT_LOAD segments", path); 1041 return NULL; 1042 } 1043 1044 obj->entry = entry; 1045 return obj; 1046 } 1047 1048 static Obj_Entry * 1049 dlcheck(void *handle) 1050 { 1051 Obj_Entry *obj; 1052 1053 for (obj = obj_list; obj != NULL; obj = obj->next) 1054 if (obj == (Obj_Entry *) handle) 1055 break; 1056 1057 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1058 _rtld_error("Invalid shared object handle %p", handle); 1059 return NULL; 1060 } 1061 return obj; 1062 } 1063 1064 /* 1065 * If the given object is already in the donelist, return true. Otherwise 1066 * add the object to the list and return false. 1067 */ 1068 static bool 1069 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1070 { 1071 unsigned int i; 1072 1073 for (i = 0; i < dlp->num_used; i++) 1074 if (dlp->objs[i] == obj) 1075 return true; 1076 /* 1077 * Our donelist allocation should always be sufficient. But if 1078 * our threads locking isn't working properly, more shared objects 1079 * could have been loaded since we allocated the list. That should 1080 * never happen, but we'll handle it properly just in case it does. 1081 */ 1082 if (dlp->num_used < dlp->num_alloc) 1083 dlp->objs[dlp->num_used++] = obj; 1084 return false; 1085 } 1086 1087 /* 1088 * Hash function for symbol table lookup. Don't even think about changing 1089 * this. It is specified by the System V ABI. 1090 */ 1091 unsigned long 1092 elf_hash(const char *name) 1093 { 1094 const unsigned char *p = (const unsigned char *) name; 1095 unsigned long h = 0; 1096 unsigned long g; 1097 1098 while (*p != '\0') { 1099 h = (h << 4) + *p++; 1100 if ((g = h & 0xf0000000) != 0) 1101 h ^= g >> 24; 1102 h &= ~g; 1103 } 1104 return h; 1105 } 1106 1107 /* 1108 * Find the library with the given name, and return its full pathname. 1109 * The returned string is dynamically allocated. Generates an error 1110 * message and returns NULL if the library cannot be found. 1111 * 1112 * If the second argument is non-NULL, then it refers to an already- 1113 * loaded shared object, whose library search path will be searched. 1114 * 1115 * The search order is: 1116 * LD_LIBRARY_PATH 1117 * rpath in the referencing file 1118 * ldconfig hints 1119 * /lib:/usr/lib 1120 */ 1121 static char * 1122 find_library(const char *xname, const Obj_Entry *refobj) 1123 { 1124 char *pathname; 1125 char *name; 1126 1127 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1128 if (xname[0] != '/' && !trust) { 1129 _rtld_error("Absolute pathname required for shared object \"%s\"", 1130 xname); 1131 return NULL; 1132 } 1133 if (refobj != NULL && refobj->z_origin) 1134 return origin_subst(xname, refobj->origin_path); 1135 else 1136 return xstrdup(xname); 1137 } 1138 1139 if (libmap_disable || (refobj == NULL) || 1140 (name = lm_find(refobj->path, xname)) == NULL) 1141 name = (char *)xname; 1142 1143 dbg(" Searching for \"%s\"", name); 1144 1145 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1146 (refobj != NULL && 1147 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1148 (pathname = search_library_path(name, gethints())) != NULL || 1149 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1150 return pathname; 1151 1152 if(refobj != NULL && refobj->path != NULL) { 1153 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1154 name, basename(refobj->path)); 1155 } else { 1156 _rtld_error("Shared object \"%s\" not found", name); 1157 } 1158 return NULL; 1159 } 1160 1161 /* 1162 * Given a symbol number in a referencing object, find the corresponding 1163 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1164 * no definition was found. Returns a pointer to the Obj_Entry of the 1165 * defining object via the reference parameter DEFOBJ_OUT. 1166 */ 1167 const Elf_Sym * 1168 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1169 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1170 { 1171 const Elf_Sym *ref; 1172 const Elf_Sym *def; 1173 const Obj_Entry *defobj; 1174 const Ver_Entry *ventry; 1175 const char *name; 1176 unsigned long hash; 1177 1178 /* 1179 * If we have already found this symbol, get the information from 1180 * the cache. 1181 */ 1182 if (symnum >= refobj->nchains) 1183 return NULL; /* Bad object */ 1184 if (cache != NULL && cache[symnum].sym != NULL) { 1185 *defobj_out = cache[symnum].obj; 1186 return cache[symnum].sym; 1187 } 1188 1189 ref = refobj->symtab + symnum; 1190 name = refobj->strtab + ref->st_name; 1191 defobj = NULL; 1192 1193 /* 1194 * We don't have to do a full scale lookup if the symbol is local. 1195 * We know it will bind to the instance in this load module; to 1196 * which we already have a pointer (ie ref). By not doing a lookup, 1197 * we not only improve performance, but it also avoids unresolvable 1198 * symbols when local symbols are not in the hash table. This has 1199 * been seen with the ia64 toolchain. 1200 */ 1201 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1202 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1203 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1204 symnum); 1205 } 1206 ventry = fetch_ventry(refobj, symnum); 1207 hash = elf_hash(name); 1208 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1209 } else { 1210 def = ref; 1211 defobj = refobj; 1212 } 1213 1214 /* 1215 * If we found no definition and the reference is weak, treat the 1216 * symbol as having the value zero. 1217 */ 1218 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1219 def = &sym_zero; 1220 defobj = obj_main; 1221 } 1222 1223 if (def != NULL) { 1224 *defobj_out = defobj; 1225 /* Record the information in the cache to avoid subsequent lookups. */ 1226 if (cache != NULL) { 1227 cache[symnum].sym = def; 1228 cache[symnum].obj = defobj; 1229 } 1230 } else { 1231 if (refobj != &obj_rtld) 1232 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1233 } 1234 return def; 1235 } 1236 1237 /* 1238 * Return the search path from the ldconfig hints file, reading it if 1239 * necessary. Returns NULL if there are problems with the hints file, 1240 * or if the search path there is empty. 1241 */ 1242 static const char * 1243 gethints(void) 1244 { 1245 static char *hints; 1246 1247 if (hints == NULL) { 1248 int fd; 1249 struct elfhints_hdr hdr; 1250 char *p; 1251 1252 /* Keep from trying again in case the hints file is bad. */ 1253 hints = ""; 1254 1255 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1256 return NULL; 1257 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1258 hdr.magic != ELFHINTS_MAGIC || 1259 hdr.version != 1) { 1260 close(fd); 1261 return NULL; 1262 } 1263 p = xmalloc(hdr.dirlistlen + 1); 1264 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1265 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1266 free(p); 1267 close(fd); 1268 return NULL; 1269 } 1270 hints = p; 1271 close(fd); 1272 } 1273 return hints[0] != '\0' ? hints : NULL; 1274 } 1275 1276 static void 1277 init_dag(Obj_Entry *root) 1278 { 1279 DoneList donelist; 1280 1281 donelist_init(&donelist); 1282 init_dag1(root, root, &donelist); 1283 } 1284 1285 static void 1286 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1287 { 1288 const Needed_Entry *needed; 1289 1290 if (donelist_check(dlp, obj)) 1291 return; 1292 1293 obj->refcount++; 1294 objlist_push_tail(&obj->dldags, root); 1295 objlist_push_tail(&root->dagmembers, obj); 1296 for (needed = obj->needed; needed != NULL; needed = needed->next) 1297 if (needed->obj != NULL) 1298 init_dag1(root, needed->obj, dlp); 1299 } 1300 1301 /* 1302 * Initialize the dynamic linker. The argument is the address at which 1303 * the dynamic linker has been mapped into memory. The primary task of 1304 * this function is to relocate the dynamic linker. 1305 */ 1306 static void 1307 init_rtld(caddr_t mapbase) 1308 { 1309 Obj_Entry objtmp; /* Temporary rtld object */ 1310 1311 /* 1312 * Conjure up an Obj_Entry structure for the dynamic linker. 1313 * 1314 * The "path" member can't be initialized yet because string constants 1315 * cannot yet be accessed. Below we will set it correctly. 1316 */ 1317 memset(&objtmp, 0, sizeof(objtmp)); 1318 objtmp.path = NULL; 1319 objtmp.rtld = true; 1320 objtmp.mapbase = mapbase; 1321 #ifdef PIC 1322 objtmp.relocbase = mapbase; 1323 #endif 1324 if (RTLD_IS_DYNAMIC()) { 1325 objtmp.dynamic = rtld_dynamic(&objtmp); 1326 digest_dynamic(&objtmp, 1); 1327 assert(objtmp.needed == NULL); 1328 #if !defined(__mips__) 1329 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1330 assert(!objtmp.textrel); 1331 #endif 1332 1333 /* 1334 * Temporarily put the dynamic linker entry into the object list, so 1335 * that symbols can be found. 1336 */ 1337 1338 relocate_objects(&objtmp, true, &objtmp); 1339 } 1340 1341 /* Initialize the object list. */ 1342 obj_tail = &obj_list; 1343 1344 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1345 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1346 1347 /* Replace the path with a dynamically allocated copy. */ 1348 obj_rtld.path = xstrdup(PATH_RTLD); 1349 1350 r_debug.r_brk = r_debug_state; 1351 r_debug.r_state = RT_CONSISTENT; 1352 } 1353 1354 /* 1355 * Add the init functions from a needed object list (and its recursive 1356 * needed objects) to "list". This is not used directly; it is a helper 1357 * function for initlist_add_objects(). The write lock must be held 1358 * when this function is called. 1359 */ 1360 static void 1361 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1362 { 1363 /* Recursively process the successor needed objects. */ 1364 if (needed->next != NULL) 1365 initlist_add_neededs(needed->next, list); 1366 1367 /* Process the current needed object. */ 1368 if (needed->obj != NULL) 1369 initlist_add_objects(needed->obj, &needed->obj->next, list); 1370 } 1371 1372 /* 1373 * Scan all of the DAGs rooted in the range of objects from "obj" to 1374 * "tail" and add their init functions to "list". This recurses over 1375 * the DAGs and ensure the proper init ordering such that each object's 1376 * needed libraries are initialized before the object itself. At the 1377 * same time, this function adds the objects to the global finalization 1378 * list "list_fini" in the opposite order. The write lock must be 1379 * held when this function is called. 1380 */ 1381 static void 1382 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1383 { 1384 if (obj->init_scanned || obj->init_done) 1385 return; 1386 obj->init_scanned = true; 1387 1388 /* Recursively process the successor objects. */ 1389 if (&obj->next != tail) 1390 initlist_add_objects(obj->next, tail, list); 1391 1392 /* Recursively process the needed objects. */ 1393 if (obj->needed != NULL) 1394 initlist_add_neededs(obj->needed, list); 1395 1396 /* Add the object to the init list. */ 1397 if (obj->init != (Elf_Addr)NULL) 1398 objlist_push_tail(list, obj); 1399 1400 /* Add the object to the global fini list in the reverse order. */ 1401 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1402 objlist_push_head(&list_fini, obj); 1403 obj->on_fini_list = true; 1404 } 1405 } 1406 1407 #ifndef FPTR_TARGET 1408 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1409 #endif 1410 1411 static bool 1412 is_exported(const Elf_Sym *def) 1413 { 1414 Elf_Addr value; 1415 const func_ptr_type *p; 1416 1417 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1418 for (p = exports; *p != NULL; p++) 1419 if (FPTR_TARGET(*p) == value) 1420 return true; 1421 return false; 1422 } 1423 1424 /* 1425 * Given a shared object, traverse its list of needed objects, and load 1426 * each of them. Returns 0 on success. Generates an error message and 1427 * returns -1 on failure. 1428 */ 1429 static int 1430 load_needed_objects(Obj_Entry *first, int flags) 1431 { 1432 Obj_Entry *obj, *obj1; 1433 1434 for (obj = first; obj != NULL; obj = obj->next) { 1435 Needed_Entry *needed; 1436 1437 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1438 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1439 flags & ~RTLD_LO_NOLOAD); 1440 if (obj1 == NULL && !ld_tracing) 1441 return -1; 1442 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1443 dbg("obj %s nodelete", obj1->path); 1444 init_dag(obj1); 1445 ref_dag(obj1); 1446 obj1->ref_nodel = true; 1447 } 1448 } 1449 } 1450 1451 return 0; 1452 } 1453 1454 static int 1455 load_preload_objects(void) 1456 { 1457 char *p = ld_preload; 1458 static const char delim[] = " \t:;"; 1459 1460 if (p == NULL) 1461 return 0; 1462 1463 p += strspn(p, delim); 1464 while (*p != '\0') { 1465 size_t len = strcspn(p, delim); 1466 char savech; 1467 1468 savech = p[len]; 1469 p[len] = '\0'; 1470 if (load_object(p, NULL, 0) == NULL) 1471 return -1; /* XXX - cleanup */ 1472 p[len] = savech; 1473 p += len; 1474 p += strspn(p, delim); 1475 } 1476 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1477 return 0; 1478 } 1479 1480 /* 1481 * Load a shared object into memory, if it is not already loaded. 1482 * 1483 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1484 * on failure. 1485 */ 1486 static Obj_Entry * 1487 load_object(const char *name, const Obj_Entry *refobj, int flags) 1488 { 1489 Obj_Entry *obj; 1490 int fd = -1; 1491 struct stat sb; 1492 char *path; 1493 1494 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1495 if (object_match_name(obj, name)) 1496 return obj; 1497 1498 path = find_library(name, refobj); 1499 if (path == NULL) 1500 return NULL; 1501 1502 /* 1503 * If we didn't find a match by pathname, open the file and check 1504 * again by device and inode. This avoids false mismatches caused 1505 * by multiple links or ".." in pathnames. 1506 * 1507 * To avoid a race, we open the file and use fstat() rather than 1508 * using stat(). 1509 */ 1510 if ((fd = open(path, O_RDONLY)) == -1) { 1511 _rtld_error("Cannot open \"%s\"", path); 1512 free(path); 1513 return NULL; 1514 } 1515 if (fstat(fd, &sb) == -1) { 1516 _rtld_error("Cannot fstat \"%s\"", path); 1517 close(fd); 1518 free(path); 1519 return NULL; 1520 } 1521 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1522 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1523 close(fd); 1524 break; 1525 } 1526 } 1527 if (obj != NULL) { 1528 object_add_name(obj, name); 1529 free(path); 1530 close(fd); 1531 return obj; 1532 } 1533 if (flags & RTLD_LO_NOLOAD) { 1534 free(path); 1535 return (NULL); 1536 } 1537 1538 /* First use of this object, so we must map it in */ 1539 obj = do_load_object(fd, name, path, &sb, flags); 1540 if (obj == NULL) 1541 free(path); 1542 close(fd); 1543 1544 return obj; 1545 } 1546 1547 static Obj_Entry * 1548 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1549 int flags) 1550 { 1551 Obj_Entry *obj; 1552 struct statfs fs; 1553 1554 /* 1555 * but first, make sure that environment variables haven't been 1556 * used to circumvent the noexec flag on a filesystem. 1557 */ 1558 if (dangerous_ld_env) { 1559 if (fstatfs(fd, &fs) != 0) { 1560 _rtld_error("Cannot fstatfs \"%s\"", path); 1561 return NULL; 1562 } 1563 if (fs.f_flags & MNT_NOEXEC) { 1564 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1565 return NULL; 1566 } 1567 } 1568 dbg("loading \"%s\"", path); 1569 obj = map_object(fd, path, sbp); 1570 if (obj == NULL) 1571 return NULL; 1572 1573 object_add_name(obj, name); 1574 obj->path = path; 1575 digest_dynamic(obj, 0); 1576 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1577 RTLD_LO_DLOPEN) { 1578 dbg("refusing to load non-loadable \"%s\"", obj->path); 1579 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1580 munmap(obj->mapbase, obj->mapsize); 1581 obj_free(obj); 1582 return (NULL); 1583 } 1584 1585 *obj_tail = obj; 1586 obj_tail = &obj->next; 1587 obj_count++; 1588 obj_loads++; 1589 linkmap_add(obj); /* for GDB & dlinfo() */ 1590 1591 dbg(" %p .. %p: %s", obj->mapbase, 1592 obj->mapbase + obj->mapsize - 1, obj->path); 1593 if (obj->textrel) 1594 dbg(" WARNING: %s has impure text", obj->path); 1595 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1596 obj->path); 1597 1598 return obj; 1599 } 1600 1601 static Obj_Entry * 1602 obj_from_addr(const void *addr) 1603 { 1604 Obj_Entry *obj; 1605 1606 for (obj = obj_list; obj != NULL; obj = obj->next) { 1607 if (addr < (void *) obj->mapbase) 1608 continue; 1609 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1610 return obj; 1611 } 1612 return NULL; 1613 } 1614 1615 /* 1616 * Call the finalization functions for each of the objects in "list" 1617 * which are unreferenced. All of the objects are expected to have 1618 * non-NULL fini functions. 1619 */ 1620 static void 1621 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1622 { 1623 Objlist_Entry *elm, *elm_tmp; 1624 char *saved_msg; 1625 1626 /* 1627 * Preserve the current error message since a fini function might 1628 * call into the dynamic linker and overwrite it. 1629 */ 1630 saved_msg = errmsg_save(); 1631 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1632 if (elm->obj->refcount == 0 || force) { 1633 dbg("calling fini function for %s at %p", elm->obj->path, 1634 (void *)elm->obj->fini); 1635 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1636 elm->obj->path); 1637 /* Remove object from fini list to prevent recursive invocation. */ 1638 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1639 wlock_release(rtld_bind_lock, *lockstate); 1640 call_initfini_pointer(elm->obj, elm->obj->fini); 1641 *lockstate = wlock_acquire(rtld_bind_lock); 1642 /* No need to free anything if process is going down. */ 1643 if (!force) 1644 free(elm); 1645 } 1646 } 1647 errmsg_restore(saved_msg); 1648 } 1649 1650 /* 1651 * Call the initialization functions for each of the objects in 1652 * "list". All of the objects are expected to have non-NULL init 1653 * functions. 1654 */ 1655 static void 1656 objlist_call_init(Objlist *list, int *lockstate) 1657 { 1658 Objlist_Entry *elm; 1659 Obj_Entry *obj; 1660 char *saved_msg; 1661 1662 /* 1663 * Clean init_scanned flag so that objects can be rechecked and 1664 * possibly initialized earlier if any of vectors called below 1665 * cause the change by using dlopen. 1666 */ 1667 for (obj = obj_list; obj != NULL; obj = obj->next) 1668 obj->init_scanned = false; 1669 1670 /* 1671 * Preserve the current error message since an init function might 1672 * call into the dynamic linker and overwrite it. 1673 */ 1674 saved_msg = errmsg_save(); 1675 STAILQ_FOREACH(elm, list, link) { 1676 if (elm->obj->init_done) /* Initialized early. */ 1677 continue; 1678 dbg("calling init function for %s at %p", elm->obj->path, 1679 (void *)elm->obj->init); 1680 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1681 elm->obj->path); 1682 /* 1683 * Race: other thread might try to use this object before current 1684 * one completes the initilization. Not much can be done here 1685 * without better locking. 1686 */ 1687 elm->obj->init_done = true; 1688 wlock_release(rtld_bind_lock, *lockstate); 1689 call_initfini_pointer(elm->obj, elm->obj->init); 1690 *lockstate = wlock_acquire(rtld_bind_lock); 1691 } 1692 errmsg_restore(saved_msg); 1693 } 1694 1695 static void 1696 objlist_clear(Objlist *list) 1697 { 1698 Objlist_Entry *elm; 1699 1700 while (!STAILQ_EMPTY(list)) { 1701 elm = STAILQ_FIRST(list); 1702 STAILQ_REMOVE_HEAD(list, link); 1703 free(elm); 1704 } 1705 } 1706 1707 static Objlist_Entry * 1708 objlist_find(Objlist *list, const Obj_Entry *obj) 1709 { 1710 Objlist_Entry *elm; 1711 1712 STAILQ_FOREACH(elm, list, link) 1713 if (elm->obj == obj) 1714 return elm; 1715 return NULL; 1716 } 1717 1718 static void 1719 objlist_init(Objlist *list) 1720 { 1721 STAILQ_INIT(list); 1722 } 1723 1724 static void 1725 objlist_push_head(Objlist *list, Obj_Entry *obj) 1726 { 1727 Objlist_Entry *elm; 1728 1729 elm = NEW(Objlist_Entry); 1730 elm->obj = obj; 1731 STAILQ_INSERT_HEAD(list, elm, link); 1732 } 1733 1734 static void 1735 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1736 { 1737 Objlist_Entry *elm; 1738 1739 elm = NEW(Objlist_Entry); 1740 elm->obj = obj; 1741 STAILQ_INSERT_TAIL(list, elm, link); 1742 } 1743 1744 static void 1745 objlist_remove(Objlist *list, Obj_Entry *obj) 1746 { 1747 Objlist_Entry *elm; 1748 1749 if ((elm = objlist_find(list, obj)) != NULL) { 1750 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1751 free(elm); 1752 } 1753 } 1754 1755 /* 1756 * Relocate newly-loaded shared objects. The argument is a pointer to 1757 * the Obj_Entry for the first such object. All objects from the first 1758 * to the end of the list of objects are relocated. Returns 0 on success, 1759 * or -1 on failure. 1760 */ 1761 static int 1762 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1763 { 1764 Obj_Entry *obj; 1765 1766 for (obj = first; obj != NULL; obj = obj->next) { 1767 if (obj != rtldobj) 1768 dbg("relocating \"%s\"", obj->path); 1769 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1770 obj->symtab == NULL || obj->strtab == NULL) { 1771 _rtld_error("%s: Shared object has no run-time symbol table", 1772 obj->path); 1773 return -1; 1774 } 1775 1776 if (obj->textrel) { 1777 /* There are relocations to the write-protected text segment. */ 1778 if (mprotect(obj->mapbase, obj->textsize, 1779 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1780 _rtld_error("%s: Cannot write-enable text segment: %s", 1781 obj->path, strerror(errno)); 1782 return -1; 1783 } 1784 } 1785 1786 /* Process the non-PLT relocations. */ 1787 if (reloc_non_plt(obj, rtldobj)) 1788 return -1; 1789 1790 if (obj->textrel) { /* Re-protected the text segment. */ 1791 if (mprotect(obj->mapbase, obj->textsize, 1792 PROT_READ|PROT_EXEC) == -1) { 1793 _rtld_error("%s: Cannot write-protect text segment: %s", 1794 obj->path, strerror(errno)); 1795 return -1; 1796 } 1797 } 1798 1799 /* Process the PLT relocations. */ 1800 if (reloc_plt(obj) == -1) 1801 return -1; 1802 /* Relocate the jump slots if we are doing immediate binding. */ 1803 if (obj->bind_now || bind_now) 1804 if (reloc_jmpslots(obj) == -1) 1805 return -1; 1806 1807 1808 /* 1809 * Set up the magic number and version in the Obj_Entry. These 1810 * were checked in the crt1.o from the original ElfKit, so we 1811 * set them for backward compatibility. 1812 */ 1813 obj->magic = RTLD_MAGIC; 1814 obj->version = RTLD_VERSION; 1815 1816 /* Set the special PLT or GOT entries. */ 1817 init_pltgot(obj); 1818 } 1819 1820 return 0; 1821 } 1822 1823 /* 1824 * Cleanup procedure. It will be called (by the atexit mechanism) just 1825 * before the process exits. 1826 */ 1827 static void 1828 rtld_exit(void) 1829 { 1830 int lockstate; 1831 1832 lockstate = wlock_acquire(rtld_bind_lock); 1833 dbg("rtld_exit()"); 1834 objlist_call_fini(&list_fini, true, &lockstate); 1835 /* No need to remove the items from the list, since we are exiting. */ 1836 if (!libmap_disable) 1837 lm_fini(); 1838 wlock_release(rtld_bind_lock, lockstate); 1839 } 1840 1841 static void * 1842 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1843 { 1844 #ifdef COMPAT_32BIT 1845 const char *trans; 1846 #endif 1847 if (path == NULL) 1848 return (NULL); 1849 1850 path += strspn(path, ":;"); 1851 while (*path != '\0') { 1852 size_t len; 1853 char *res; 1854 1855 len = strcspn(path, ":;"); 1856 #ifdef COMPAT_32BIT 1857 trans = lm_findn(NULL, path, len); 1858 if (trans) 1859 res = callback(trans, strlen(trans), arg); 1860 else 1861 #endif 1862 res = callback(path, len, arg); 1863 1864 if (res != NULL) 1865 return (res); 1866 1867 path += len; 1868 path += strspn(path, ":;"); 1869 } 1870 1871 return (NULL); 1872 } 1873 1874 struct try_library_args { 1875 const char *name; 1876 size_t namelen; 1877 char *buffer; 1878 size_t buflen; 1879 }; 1880 1881 static void * 1882 try_library_path(const char *dir, size_t dirlen, void *param) 1883 { 1884 struct try_library_args *arg; 1885 1886 arg = param; 1887 if (*dir == '/' || trust) { 1888 char *pathname; 1889 1890 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1891 return (NULL); 1892 1893 pathname = arg->buffer; 1894 strncpy(pathname, dir, dirlen); 1895 pathname[dirlen] = '/'; 1896 strcpy(pathname + dirlen + 1, arg->name); 1897 1898 dbg(" Trying \"%s\"", pathname); 1899 if (access(pathname, F_OK) == 0) { /* We found it */ 1900 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1901 strcpy(pathname, arg->buffer); 1902 return (pathname); 1903 } 1904 } 1905 return (NULL); 1906 } 1907 1908 static char * 1909 search_library_path(const char *name, const char *path) 1910 { 1911 char *p; 1912 struct try_library_args arg; 1913 1914 if (path == NULL) 1915 return NULL; 1916 1917 arg.name = name; 1918 arg.namelen = strlen(name); 1919 arg.buffer = xmalloc(PATH_MAX); 1920 arg.buflen = PATH_MAX; 1921 1922 p = path_enumerate(path, try_library_path, &arg); 1923 1924 free(arg.buffer); 1925 1926 return (p); 1927 } 1928 1929 int 1930 dlclose(void *handle) 1931 { 1932 Obj_Entry *root; 1933 int lockstate; 1934 1935 lockstate = wlock_acquire(rtld_bind_lock); 1936 root = dlcheck(handle); 1937 if (root == NULL) { 1938 wlock_release(rtld_bind_lock, lockstate); 1939 return -1; 1940 } 1941 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1942 root->path); 1943 1944 /* Unreference the object and its dependencies. */ 1945 root->dl_refcount--; 1946 1947 unref_dag(root); 1948 1949 if (root->refcount == 0) { 1950 /* 1951 * The object is no longer referenced, so we must unload it. 1952 * First, call the fini functions. 1953 */ 1954 objlist_call_fini(&list_fini, false, &lockstate); 1955 1956 /* Finish cleaning up the newly-unreferenced objects. */ 1957 GDB_STATE(RT_DELETE,&root->linkmap); 1958 unload_object(root); 1959 GDB_STATE(RT_CONSISTENT,NULL); 1960 } 1961 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1962 wlock_release(rtld_bind_lock, lockstate); 1963 return 0; 1964 } 1965 1966 char * 1967 dlerror(void) 1968 { 1969 char *msg = error_message; 1970 error_message = NULL; 1971 return msg; 1972 } 1973 1974 /* 1975 * This function is deprecated and has no effect. 1976 */ 1977 void 1978 dllockinit(void *context, 1979 void *(*lock_create)(void *context), 1980 void (*rlock_acquire)(void *lock), 1981 void (*wlock_acquire)(void *lock), 1982 void (*lock_release)(void *lock), 1983 void (*lock_destroy)(void *lock), 1984 void (*context_destroy)(void *context)) 1985 { 1986 static void *cur_context; 1987 static void (*cur_context_destroy)(void *); 1988 1989 /* Just destroy the context from the previous call, if necessary. */ 1990 if (cur_context_destroy != NULL) 1991 cur_context_destroy(cur_context); 1992 cur_context = context; 1993 cur_context_destroy = context_destroy; 1994 } 1995 1996 void * 1997 dlopen(const char *name, int mode) 1998 { 1999 Obj_Entry **old_obj_tail; 2000 Obj_Entry *obj; 2001 Objlist initlist; 2002 int result, lockstate, nodelete, lo_flags; 2003 2004 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2005 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2006 if (ld_tracing != NULL) 2007 environ = (char **)*get_program_var_addr("environ"); 2008 nodelete = mode & RTLD_NODELETE; 2009 lo_flags = RTLD_LO_DLOPEN; 2010 if (mode & RTLD_NOLOAD) 2011 lo_flags |= RTLD_LO_NOLOAD; 2012 if (ld_tracing != NULL) 2013 lo_flags |= RTLD_LO_TRACE; 2014 2015 objlist_init(&initlist); 2016 2017 lockstate = wlock_acquire(rtld_bind_lock); 2018 GDB_STATE(RT_ADD,NULL); 2019 2020 old_obj_tail = obj_tail; 2021 obj = NULL; 2022 if (name == NULL) { 2023 obj = obj_main; 2024 obj->refcount++; 2025 } else { 2026 obj = load_object(name, obj_main, lo_flags); 2027 } 2028 2029 if (obj) { 2030 obj->dl_refcount++; 2031 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2032 objlist_push_tail(&list_global, obj); 2033 mode &= RTLD_MODEMASK; 2034 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2035 assert(*old_obj_tail == obj); 2036 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2037 init_dag(obj); 2038 if (result != -1) 2039 result = rtld_verify_versions(&obj->dagmembers); 2040 if (result != -1 && ld_tracing) 2041 goto trace; 2042 if (result == -1 || 2043 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2044 obj->dl_refcount--; 2045 unref_dag(obj); 2046 if (obj->refcount == 0) 2047 unload_object(obj); 2048 obj = NULL; 2049 } else { 2050 /* Make list of init functions to call. */ 2051 initlist_add_objects(obj, &obj->next, &initlist); 2052 } 2053 } else { 2054 2055 /* Bump the reference counts for objects on this DAG. */ 2056 ref_dag(obj); 2057 2058 if (ld_tracing) 2059 goto trace; 2060 } 2061 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2062 dbg("obj %s nodelete", obj->path); 2063 ref_dag(obj); 2064 obj->z_nodelete = obj->ref_nodel = true; 2065 } 2066 } 2067 2068 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2069 name); 2070 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2071 2072 /* Call the init functions. */ 2073 objlist_call_init(&initlist, &lockstate); 2074 objlist_clear(&initlist); 2075 wlock_release(rtld_bind_lock, lockstate); 2076 return obj; 2077 trace: 2078 trace_loaded_objects(obj); 2079 wlock_release(rtld_bind_lock, lockstate); 2080 exit(0); 2081 } 2082 2083 static void * 2084 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2085 int flags) 2086 { 2087 DoneList donelist; 2088 const Obj_Entry *obj, *defobj; 2089 const Elf_Sym *def, *symp; 2090 unsigned long hash; 2091 int lockstate; 2092 2093 hash = elf_hash(name); 2094 def = NULL; 2095 defobj = NULL; 2096 flags |= SYMLOOK_IN_PLT; 2097 2098 lockstate = rlock_acquire(rtld_bind_lock); 2099 if (handle == NULL || handle == RTLD_NEXT || 2100 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2101 2102 if ((obj = obj_from_addr(retaddr)) == NULL) { 2103 _rtld_error("Cannot determine caller's shared object"); 2104 rlock_release(rtld_bind_lock, lockstate); 2105 return NULL; 2106 } 2107 if (handle == NULL) { /* Just the caller's shared object. */ 2108 def = symlook_obj(name, hash, obj, ve, flags); 2109 defobj = obj; 2110 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2111 handle == RTLD_SELF) { /* ... caller included */ 2112 if (handle == RTLD_NEXT) 2113 obj = obj->next; 2114 for (; obj != NULL; obj = obj->next) { 2115 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2116 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2117 def = symp; 2118 defobj = obj; 2119 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2120 break; 2121 } 2122 } 2123 } 2124 /* 2125 * Search the dynamic linker itself, and possibly resolve the 2126 * symbol from there. This is how the application links to 2127 * dynamic linker services such as dlopen. Only the values listed 2128 * in the "exports" array can be resolved from the dynamic linker. 2129 */ 2130 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2131 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2132 if (symp != NULL && is_exported(symp)) { 2133 def = symp; 2134 defobj = &obj_rtld; 2135 } 2136 } 2137 } else { 2138 assert(handle == RTLD_DEFAULT); 2139 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2140 } 2141 } else { 2142 if ((obj = dlcheck(handle)) == NULL) { 2143 rlock_release(rtld_bind_lock, lockstate); 2144 return NULL; 2145 } 2146 2147 donelist_init(&donelist); 2148 if (obj->mainprog) { 2149 /* Search main program and all libraries loaded by it. */ 2150 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2151 &donelist); 2152 2153 /* 2154 * We do not distinguish between 'main' object and global scope. 2155 * If symbol is not defined by objects loaded at startup, continue 2156 * search among dynamically loaded objects with RTLD_GLOBAL 2157 * scope. 2158 */ 2159 if (def == NULL) 2160 def = symlook_list(name, hash, &list_global, &defobj, ve, 2161 flags, &donelist); 2162 } else { 2163 Needed_Entry fake; 2164 2165 /* Search the whole DAG rooted at the given object. */ 2166 fake.next = NULL; 2167 fake.obj = (Obj_Entry *)obj; 2168 fake.name = 0; 2169 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2170 &donelist); 2171 } 2172 } 2173 2174 if (def != NULL) { 2175 rlock_release(rtld_bind_lock, lockstate); 2176 2177 /* 2178 * The value required by the caller is derived from the value 2179 * of the symbol. For the ia64 architecture, we need to 2180 * construct a function descriptor which the caller can use to 2181 * call the function with the right 'gp' value. For other 2182 * architectures and for non-functions, the value is simply 2183 * the relocated value of the symbol. 2184 */ 2185 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2186 return make_function_pointer(def, defobj); 2187 else 2188 return defobj->relocbase + def->st_value; 2189 } 2190 2191 _rtld_error("Undefined symbol \"%s\"", name); 2192 rlock_release(rtld_bind_lock, lockstate); 2193 return NULL; 2194 } 2195 2196 void * 2197 dlsym(void *handle, const char *name) 2198 { 2199 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2200 SYMLOOK_DLSYM); 2201 } 2202 2203 dlfunc_t 2204 dlfunc(void *handle, const char *name) 2205 { 2206 union { 2207 void *d; 2208 dlfunc_t f; 2209 } rv; 2210 2211 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2212 SYMLOOK_DLSYM); 2213 return (rv.f); 2214 } 2215 2216 void * 2217 dlvsym(void *handle, const char *name, const char *version) 2218 { 2219 Ver_Entry ventry; 2220 2221 ventry.name = version; 2222 ventry.file = NULL; 2223 ventry.hash = elf_hash(version); 2224 ventry.flags= 0; 2225 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2226 SYMLOOK_DLSYM); 2227 } 2228 2229 int 2230 dladdr(const void *addr, Dl_info *info) 2231 { 2232 const Obj_Entry *obj; 2233 const Elf_Sym *def; 2234 void *symbol_addr; 2235 unsigned long symoffset; 2236 int lockstate; 2237 2238 lockstate = rlock_acquire(rtld_bind_lock); 2239 obj = obj_from_addr(addr); 2240 if (obj == NULL) { 2241 _rtld_error("No shared object contains address"); 2242 rlock_release(rtld_bind_lock, lockstate); 2243 return 0; 2244 } 2245 info->dli_fname = obj->path; 2246 info->dli_fbase = obj->mapbase; 2247 info->dli_saddr = (void *)0; 2248 info->dli_sname = NULL; 2249 2250 /* 2251 * Walk the symbol list looking for the symbol whose address is 2252 * closest to the address sent in. 2253 */ 2254 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2255 def = obj->symtab + symoffset; 2256 2257 /* 2258 * For skip the symbol if st_shndx is either SHN_UNDEF or 2259 * SHN_COMMON. 2260 */ 2261 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2262 continue; 2263 2264 /* 2265 * If the symbol is greater than the specified address, or if it 2266 * is further away from addr than the current nearest symbol, 2267 * then reject it. 2268 */ 2269 symbol_addr = obj->relocbase + def->st_value; 2270 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2271 continue; 2272 2273 /* Update our idea of the nearest symbol. */ 2274 info->dli_sname = obj->strtab + def->st_name; 2275 info->dli_saddr = symbol_addr; 2276 2277 /* Exact match? */ 2278 if (info->dli_saddr == addr) 2279 break; 2280 } 2281 rlock_release(rtld_bind_lock, lockstate); 2282 return 1; 2283 } 2284 2285 int 2286 dlinfo(void *handle, int request, void *p) 2287 { 2288 const Obj_Entry *obj; 2289 int error, lockstate; 2290 2291 lockstate = rlock_acquire(rtld_bind_lock); 2292 2293 if (handle == NULL || handle == RTLD_SELF) { 2294 void *retaddr; 2295 2296 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2297 if ((obj = obj_from_addr(retaddr)) == NULL) 2298 _rtld_error("Cannot determine caller's shared object"); 2299 } else 2300 obj = dlcheck(handle); 2301 2302 if (obj == NULL) { 2303 rlock_release(rtld_bind_lock, lockstate); 2304 return (-1); 2305 } 2306 2307 error = 0; 2308 switch (request) { 2309 case RTLD_DI_LINKMAP: 2310 *((struct link_map const **)p) = &obj->linkmap; 2311 break; 2312 case RTLD_DI_ORIGIN: 2313 error = rtld_dirname(obj->path, p); 2314 break; 2315 2316 case RTLD_DI_SERINFOSIZE: 2317 case RTLD_DI_SERINFO: 2318 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2319 break; 2320 2321 default: 2322 _rtld_error("Invalid request %d passed to dlinfo()", request); 2323 error = -1; 2324 } 2325 2326 rlock_release(rtld_bind_lock, lockstate); 2327 2328 return (error); 2329 } 2330 2331 int 2332 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2333 { 2334 struct dl_phdr_info phdr_info; 2335 const Obj_Entry *obj; 2336 int error, bind_lockstate, phdr_lockstate; 2337 2338 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2339 bind_lockstate = rlock_acquire(rtld_bind_lock); 2340 2341 error = 0; 2342 2343 for (obj = obj_list; obj != NULL; obj = obj->next) { 2344 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2345 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2346 STAILQ_FIRST(&obj->names)->name : obj->path; 2347 phdr_info.dlpi_phdr = obj->phdr; 2348 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2349 phdr_info.dlpi_tls_modid = obj->tlsindex; 2350 phdr_info.dlpi_tls_data = obj->tlsinit; 2351 phdr_info.dlpi_adds = obj_loads; 2352 phdr_info.dlpi_subs = obj_loads - obj_count; 2353 2354 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2355 break; 2356 2357 } 2358 rlock_release(rtld_bind_lock, bind_lockstate); 2359 wlock_release(rtld_phdr_lock, phdr_lockstate); 2360 2361 return (error); 2362 } 2363 2364 struct fill_search_info_args { 2365 int request; 2366 unsigned int flags; 2367 Dl_serinfo *serinfo; 2368 Dl_serpath *serpath; 2369 char *strspace; 2370 }; 2371 2372 static void * 2373 fill_search_info(const char *dir, size_t dirlen, void *param) 2374 { 2375 struct fill_search_info_args *arg; 2376 2377 arg = param; 2378 2379 if (arg->request == RTLD_DI_SERINFOSIZE) { 2380 arg->serinfo->dls_cnt ++; 2381 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2382 } else { 2383 struct dl_serpath *s_entry; 2384 2385 s_entry = arg->serpath; 2386 s_entry->dls_name = arg->strspace; 2387 s_entry->dls_flags = arg->flags; 2388 2389 strncpy(arg->strspace, dir, dirlen); 2390 arg->strspace[dirlen] = '\0'; 2391 2392 arg->strspace += dirlen + 1; 2393 arg->serpath++; 2394 } 2395 2396 return (NULL); 2397 } 2398 2399 static int 2400 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2401 { 2402 struct dl_serinfo _info; 2403 struct fill_search_info_args args; 2404 2405 args.request = RTLD_DI_SERINFOSIZE; 2406 args.serinfo = &_info; 2407 2408 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2409 _info.dls_cnt = 0; 2410 2411 path_enumerate(ld_library_path, fill_search_info, &args); 2412 path_enumerate(obj->rpath, fill_search_info, &args); 2413 path_enumerate(gethints(), fill_search_info, &args); 2414 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2415 2416 2417 if (request == RTLD_DI_SERINFOSIZE) { 2418 info->dls_size = _info.dls_size; 2419 info->dls_cnt = _info.dls_cnt; 2420 return (0); 2421 } 2422 2423 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2424 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2425 return (-1); 2426 } 2427 2428 args.request = RTLD_DI_SERINFO; 2429 args.serinfo = info; 2430 args.serpath = &info->dls_serpath[0]; 2431 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2432 2433 args.flags = LA_SER_LIBPATH; 2434 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2435 return (-1); 2436 2437 args.flags = LA_SER_RUNPATH; 2438 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2439 return (-1); 2440 2441 args.flags = LA_SER_CONFIG; 2442 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2443 return (-1); 2444 2445 args.flags = LA_SER_DEFAULT; 2446 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2447 return (-1); 2448 return (0); 2449 } 2450 2451 static int 2452 rtld_dirname(const char *path, char *bname) 2453 { 2454 const char *endp; 2455 2456 /* Empty or NULL string gets treated as "." */ 2457 if (path == NULL || *path == '\0') { 2458 bname[0] = '.'; 2459 bname[1] = '\0'; 2460 return (0); 2461 } 2462 2463 /* Strip trailing slashes */ 2464 endp = path + strlen(path) - 1; 2465 while (endp > path && *endp == '/') 2466 endp--; 2467 2468 /* Find the start of the dir */ 2469 while (endp > path && *endp != '/') 2470 endp--; 2471 2472 /* Either the dir is "/" or there are no slashes */ 2473 if (endp == path) { 2474 bname[0] = *endp == '/' ? '/' : '.'; 2475 bname[1] = '\0'; 2476 return (0); 2477 } else { 2478 do { 2479 endp--; 2480 } while (endp > path && *endp == '/'); 2481 } 2482 2483 if (endp - path + 2 > PATH_MAX) 2484 { 2485 _rtld_error("Filename is too long: %s", path); 2486 return(-1); 2487 } 2488 2489 strncpy(bname, path, endp - path + 1); 2490 bname[endp - path + 1] = '\0'; 2491 return (0); 2492 } 2493 2494 static int 2495 rtld_dirname_abs(const char *path, char *base) 2496 { 2497 char base_rel[PATH_MAX]; 2498 2499 if (rtld_dirname(path, base) == -1) 2500 return (-1); 2501 if (base[0] == '/') 2502 return (0); 2503 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2504 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2505 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2506 return (-1); 2507 strcpy(base, base_rel); 2508 return (0); 2509 } 2510 2511 static void 2512 linkmap_add(Obj_Entry *obj) 2513 { 2514 struct link_map *l = &obj->linkmap; 2515 struct link_map *prev; 2516 2517 obj->linkmap.l_name = obj->path; 2518 obj->linkmap.l_addr = obj->mapbase; 2519 obj->linkmap.l_ld = obj->dynamic; 2520 #ifdef __mips__ 2521 /* GDB needs load offset on MIPS to use the symbols */ 2522 obj->linkmap.l_offs = obj->relocbase; 2523 #endif 2524 2525 if (r_debug.r_map == NULL) { 2526 r_debug.r_map = l; 2527 return; 2528 } 2529 2530 /* 2531 * Scan to the end of the list, but not past the entry for the 2532 * dynamic linker, which we want to keep at the very end. 2533 */ 2534 for (prev = r_debug.r_map; 2535 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2536 prev = prev->l_next) 2537 ; 2538 2539 /* Link in the new entry. */ 2540 l->l_prev = prev; 2541 l->l_next = prev->l_next; 2542 if (l->l_next != NULL) 2543 l->l_next->l_prev = l; 2544 prev->l_next = l; 2545 } 2546 2547 static void 2548 linkmap_delete(Obj_Entry *obj) 2549 { 2550 struct link_map *l = &obj->linkmap; 2551 2552 if (l->l_prev == NULL) { 2553 if ((r_debug.r_map = l->l_next) != NULL) 2554 l->l_next->l_prev = NULL; 2555 return; 2556 } 2557 2558 if ((l->l_prev->l_next = l->l_next) != NULL) 2559 l->l_next->l_prev = l->l_prev; 2560 } 2561 2562 /* 2563 * Function for the debugger to set a breakpoint on to gain control. 2564 * 2565 * The two parameters allow the debugger to easily find and determine 2566 * what the runtime loader is doing and to whom it is doing it. 2567 * 2568 * When the loadhook trap is hit (r_debug_state, set at program 2569 * initialization), the arguments can be found on the stack: 2570 * 2571 * +8 struct link_map *m 2572 * +4 struct r_debug *rd 2573 * +0 RetAddr 2574 */ 2575 void 2576 r_debug_state(struct r_debug* rd, struct link_map *m) 2577 { 2578 } 2579 2580 /* 2581 * Get address of the pointer variable in the main program. 2582 */ 2583 static const void ** 2584 get_program_var_addr(const char *name) 2585 { 2586 const Obj_Entry *obj; 2587 unsigned long hash; 2588 2589 hash = elf_hash(name); 2590 for (obj = obj_main; obj != NULL; obj = obj->next) { 2591 const Elf_Sym *def; 2592 2593 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2594 const void **addr; 2595 2596 addr = (const void **)(obj->relocbase + def->st_value); 2597 return addr; 2598 } 2599 } 2600 return NULL; 2601 } 2602 2603 /* 2604 * Set a pointer variable in the main program to the given value. This 2605 * is used to set key variables such as "environ" before any of the 2606 * init functions are called. 2607 */ 2608 static void 2609 set_program_var(const char *name, const void *value) 2610 { 2611 const void **addr; 2612 2613 if ((addr = get_program_var_addr(name)) != NULL) { 2614 dbg("\"%s\": *%p <-- %p", name, addr, value); 2615 *addr = value; 2616 } 2617 } 2618 2619 /* 2620 * Given a symbol name in a referencing object, find the corresponding 2621 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2622 * no definition was found. Returns a pointer to the Obj_Entry of the 2623 * defining object via the reference parameter DEFOBJ_OUT. 2624 */ 2625 static const Elf_Sym * 2626 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2627 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2628 { 2629 DoneList donelist; 2630 const Elf_Sym *def; 2631 const Elf_Sym *symp; 2632 const Obj_Entry *obj; 2633 const Obj_Entry *defobj; 2634 const Objlist_Entry *elm; 2635 def = NULL; 2636 defobj = NULL; 2637 donelist_init(&donelist); 2638 2639 /* Look first in the referencing object if linked symbolically. */ 2640 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2641 symp = symlook_obj(name, hash, refobj, ventry, flags); 2642 if (symp != NULL) { 2643 def = symp; 2644 defobj = refobj; 2645 } 2646 } 2647 2648 /* Search all objects loaded at program start up. */ 2649 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2650 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2651 &donelist); 2652 if (symp != NULL && 2653 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2654 def = symp; 2655 defobj = obj; 2656 } 2657 } 2658 2659 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2660 STAILQ_FOREACH(elm, &list_global, link) { 2661 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2662 break; 2663 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2664 flags, &donelist); 2665 if (symp != NULL && 2666 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2667 def = symp; 2668 defobj = obj; 2669 } 2670 } 2671 2672 /* Search all dlopened DAGs containing the referencing object. */ 2673 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2674 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2675 break; 2676 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2677 flags, &donelist); 2678 if (symp != NULL && 2679 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2680 def = symp; 2681 defobj = obj; 2682 } 2683 } 2684 2685 /* 2686 * Search the dynamic linker itself, and possibly resolve the 2687 * symbol from there. This is how the application links to 2688 * dynamic linker services such as dlopen. Only the values listed 2689 * in the "exports" array can be resolved from the dynamic linker. 2690 */ 2691 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2692 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2693 if (symp != NULL && is_exported(symp)) { 2694 def = symp; 2695 defobj = &obj_rtld; 2696 } 2697 } 2698 2699 if (def != NULL) 2700 *defobj_out = defobj; 2701 return def; 2702 } 2703 2704 static const Elf_Sym * 2705 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2706 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2707 DoneList *dlp) 2708 { 2709 const Elf_Sym *symp; 2710 const Elf_Sym *def; 2711 const Obj_Entry *defobj; 2712 const Objlist_Entry *elm; 2713 2714 def = NULL; 2715 defobj = NULL; 2716 STAILQ_FOREACH(elm, objlist, link) { 2717 if (donelist_check(dlp, elm->obj)) 2718 continue; 2719 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2720 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2721 def = symp; 2722 defobj = elm->obj; 2723 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2724 break; 2725 } 2726 } 2727 } 2728 if (def != NULL) 2729 *defobj_out = defobj; 2730 return def; 2731 } 2732 2733 /* 2734 * Search the symbol table of a shared object and all objects needed 2735 * by it for a symbol of the given name. Search order is 2736 * breadth-first. Returns a pointer to the symbol, or NULL if no 2737 * definition was found. 2738 */ 2739 static const Elf_Sym * 2740 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2741 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2742 DoneList *dlp) 2743 { 2744 const Elf_Sym *def, *def_w; 2745 const Needed_Entry *n; 2746 const Obj_Entry *obj, *defobj, *defobj1; 2747 2748 def = def_w = NULL; 2749 defobj = NULL; 2750 for (n = needed; n != NULL; n = n->next) { 2751 if ((obj = n->obj) == NULL || 2752 donelist_check(dlp, obj) || 2753 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2754 continue; 2755 defobj = obj; 2756 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2757 *defobj_out = defobj; 2758 return (def); 2759 } 2760 } 2761 /* 2762 * There we come when either symbol definition is not found in 2763 * directly needed objects, or found symbol is weak. 2764 */ 2765 for (n = needed; n != NULL; n = n->next) { 2766 if ((obj = n->obj) == NULL) 2767 continue; 2768 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2769 ventry, flags, dlp); 2770 if (def_w == NULL) 2771 continue; 2772 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2773 def = def_w; 2774 defobj = defobj1; 2775 } 2776 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2777 break; 2778 } 2779 if (def != NULL) 2780 *defobj_out = defobj; 2781 return (def); 2782 } 2783 2784 /* 2785 * Search the symbol table of a single shared object for a symbol of 2786 * the given name and version, if requested. Returns a pointer to the 2787 * symbol, or NULL if no definition was found. 2788 * 2789 * The symbol's hash value is passed in for efficiency reasons; that 2790 * eliminates many recomputations of the hash value. 2791 */ 2792 const Elf_Sym * 2793 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2794 const Ver_Entry *ventry, int flags) 2795 { 2796 unsigned long symnum; 2797 const Elf_Sym *vsymp; 2798 Elf_Versym verndx; 2799 int vcount; 2800 2801 if (obj->buckets == NULL) 2802 return NULL; 2803 2804 vsymp = NULL; 2805 vcount = 0; 2806 symnum = obj->buckets[hash % obj->nbuckets]; 2807 2808 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2809 const Elf_Sym *symp; 2810 const char *strp; 2811 2812 if (symnum >= obj->nchains) 2813 return NULL; /* Bad object */ 2814 2815 symp = obj->symtab + symnum; 2816 strp = obj->strtab + symp->st_name; 2817 2818 switch (ELF_ST_TYPE(symp->st_info)) { 2819 case STT_FUNC: 2820 case STT_NOTYPE: 2821 case STT_OBJECT: 2822 if (symp->st_value == 0) 2823 continue; 2824 /* fallthrough */ 2825 case STT_TLS: 2826 if (symp->st_shndx != SHN_UNDEF) 2827 break; 2828 #ifndef __mips__ 2829 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2830 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2831 break; 2832 /* fallthrough */ 2833 #endif 2834 default: 2835 continue; 2836 } 2837 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2838 continue; 2839 2840 if (ventry == NULL) { 2841 if (obj->versyms != NULL) { 2842 verndx = VER_NDX(obj->versyms[symnum]); 2843 if (verndx > obj->vernum) { 2844 _rtld_error("%s: symbol %s references wrong version %d", 2845 obj->path, obj->strtab + symnum, verndx); 2846 continue; 2847 } 2848 /* 2849 * If we are not called from dlsym (i.e. this is a normal 2850 * relocation from unversioned binary, accept the symbol 2851 * immediately if it happens to have first version after 2852 * this shared object became versioned. Otherwise, if 2853 * symbol is versioned and not hidden, remember it. If it 2854 * is the only symbol with this name exported by the 2855 * shared object, it will be returned as a match at the 2856 * end of the function. If symbol is global (verndx < 2) 2857 * accept it unconditionally. 2858 */ 2859 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2860 return symp; 2861 else if (verndx >= VER_NDX_GIVEN) { 2862 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2863 if (vsymp == NULL) 2864 vsymp = symp; 2865 vcount ++; 2866 } 2867 continue; 2868 } 2869 } 2870 return symp; 2871 } else { 2872 if (obj->versyms == NULL) { 2873 if (object_match_name(obj, ventry->name)) { 2874 _rtld_error("%s: object %s should provide version %s for " 2875 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2876 obj->strtab + symnum); 2877 continue; 2878 } 2879 } else { 2880 verndx = VER_NDX(obj->versyms[symnum]); 2881 if (verndx > obj->vernum) { 2882 _rtld_error("%s: symbol %s references wrong version %d", 2883 obj->path, obj->strtab + symnum, verndx); 2884 continue; 2885 } 2886 if (obj->vertab[verndx].hash != ventry->hash || 2887 strcmp(obj->vertab[verndx].name, ventry->name)) { 2888 /* 2889 * Version does not match. Look if this is a global symbol 2890 * and if it is not hidden. If global symbol (verndx < 2) 2891 * is available, use it. Do not return symbol if we are 2892 * called by dlvsym, because dlvsym looks for a specific 2893 * version and default one is not what dlvsym wants. 2894 */ 2895 if ((flags & SYMLOOK_DLSYM) || 2896 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2897 (verndx >= VER_NDX_GIVEN)) 2898 continue; 2899 } 2900 } 2901 return symp; 2902 } 2903 } 2904 return (vcount == 1) ? vsymp : NULL; 2905 } 2906 2907 static void 2908 trace_loaded_objects(Obj_Entry *obj) 2909 { 2910 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2911 int c; 2912 2913 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2914 main_local = ""; 2915 2916 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2917 fmt1 = "\t%o => %p (%x)\n"; 2918 2919 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2920 fmt2 = "\t%o (%x)\n"; 2921 2922 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2923 2924 for (; obj; obj = obj->next) { 2925 Needed_Entry *needed; 2926 char *name, *path; 2927 bool is_lib; 2928 2929 if (list_containers && obj->needed != NULL) 2930 printf("%s:\n", obj->path); 2931 for (needed = obj->needed; needed; needed = needed->next) { 2932 if (needed->obj != NULL) { 2933 if (needed->obj->traced && !list_containers) 2934 continue; 2935 needed->obj->traced = true; 2936 path = needed->obj->path; 2937 } else 2938 path = "not found"; 2939 2940 name = (char *)obj->strtab + needed->name; 2941 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2942 2943 fmt = is_lib ? fmt1 : fmt2; 2944 while ((c = *fmt++) != '\0') { 2945 switch (c) { 2946 default: 2947 putchar(c); 2948 continue; 2949 case '\\': 2950 switch (c = *fmt) { 2951 case '\0': 2952 continue; 2953 case 'n': 2954 putchar('\n'); 2955 break; 2956 case 't': 2957 putchar('\t'); 2958 break; 2959 } 2960 break; 2961 case '%': 2962 switch (c = *fmt) { 2963 case '\0': 2964 continue; 2965 case '%': 2966 default: 2967 putchar(c); 2968 break; 2969 case 'A': 2970 printf("%s", main_local); 2971 break; 2972 case 'a': 2973 printf("%s", obj_main->path); 2974 break; 2975 case 'o': 2976 printf("%s", name); 2977 break; 2978 #if 0 2979 case 'm': 2980 printf("%d", sodp->sod_major); 2981 break; 2982 case 'n': 2983 printf("%d", sodp->sod_minor); 2984 break; 2985 #endif 2986 case 'p': 2987 printf("%s", path); 2988 break; 2989 case 'x': 2990 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2991 break; 2992 } 2993 break; 2994 } 2995 ++fmt; 2996 } 2997 } 2998 } 2999 } 3000 3001 /* 3002 * Unload a dlopened object and its dependencies from memory and from 3003 * our data structures. It is assumed that the DAG rooted in the 3004 * object has already been unreferenced, and that the object has a 3005 * reference count of 0. 3006 */ 3007 static void 3008 unload_object(Obj_Entry *root) 3009 { 3010 Obj_Entry *obj; 3011 Obj_Entry **linkp; 3012 3013 assert(root->refcount == 0); 3014 3015 /* 3016 * Pass over the DAG removing unreferenced objects from 3017 * appropriate lists. 3018 */ 3019 unlink_object(root); 3020 3021 /* Unmap all objects that are no longer referenced. */ 3022 linkp = &obj_list->next; 3023 while ((obj = *linkp) != NULL) { 3024 if (obj->refcount == 0) { 3025 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3026 obj->path); 3027 dbg("unloading \"%s\"", obj->path); 3028 munmap(obj->mapbase, obj->mapsize); 3029 linkmap_delete(obj); 3030 *linkp = obj->next; 3031 obj_count--; 3032 obj_free(obj); 3033 } else 3034 linkp = &obj->next; 3035 } 3036 obj_tail = linkp; 3037 } 3038 3039 static void 3040 unlink_object(Obj_Entry *root) 3041 { 3042 Objlist_Entry *elm; 3043 3044 if (root->refcount == 0) { 3045 /* Remove the object from the RTLD_GLOBAL list. */ 3046 objlist_remove(&list_global, root); 3047 3048 /* Remove the object from all objects' DAG lists. */ 3049 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3050 objlist_remove(&elm->obj->dldags, root); 3051 if (elm->obj != root) 3052 unlink_object(elm->obj); 3053 } 3054 } 3055 } 3056 3057 static void 3058 ref_dag(Obj_Entry *root) 3059 { 3060 Objlist_Entry *elm; 3061 3062 STAILQ_FOREACH(elm, &root->dagmembers, link) 3063 elm->obj->refcount++; 3064 } 3065 3066 static void 3067 unref_dag(Obj_Entry *root) 3068 { 3069 Objlist_Entry *elm; 3070 3071 STAILQ_FOREACH(elm, &root->dagmembers, link) 3072 elm->obj->refcount--; 3073 } 3074 3075 /* 3076 * Common code for MD __tls_get_addr(). 3077 */ 3078 void * 3079 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3080 { 3081 Elf_Addr* dtv = *dtvp; 3082 int lockstate; 3083 3084 /* Check dtv generation in case new modules have arrived */ 3085 if (dtv[0] != tls_dtv_generation) { 3086 Elf_Addr* newdtv; 3087 int to_copy; 3088 3089 lockstate = wlock_acquire(rtld_bind_lock); 3090 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3091 to_copy = dtv[1]; 3092 if (to_copy > tls_max_index) 3093 to_copy = tls_max_index; 3094 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3095 newdtv[0] = tls_dtv_generation; 3096 newdtv[1] = tls_max_index; 3097 free(dtv); 3098 wlock_release(rtld_bind_lock, lockstate); 3099 *dtvp = newdtv; 3100 } 3101 3102 /* Dynamically allocate module TLS if necessary */ 3103 if (!dtv[index + 1]) { 3104 /* Signal safe, wlock will block out signals. */ 3105 lockstate = wlock_acquire(rtld_bind_lock); 3106 if (!dtv[index + 1]) 3107 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3108 wlock_release(rtld_bind_lock, lockstate); 3109 } 3110 return (void*) (dtv[index + 1] + offset); 3111 } 3112 3113 /* XXX not sure what variants to use for arm. */ 3114 3115 #if defined(__ia64__) || defined(__powerpc__) 3116 3117 /* 3118 * Allocate Static TLS using the Variant I method. 3119 */ 3120 void * 3121 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3122 { 3123 Obj_Entry *obj; 3124 char *tcb; 3125 Elf_Addr **tls; 3126 Elf_Addr *dtv; 3127 Elf_Addr addr; 3128 int i; 3129 3130 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3131 return (oldtcb); 3132 3133 assert(tcbsize >= TLS_TCB_SIZE); 3134 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3135 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3136 3137 if (oldtcb != NULL) { 3138 memcpy(tls, oldtcb, tls_static_space); 3139 free(oldtcb); 3140 3141 /* Adjust the DTV. */ 3142 dtv = tls[0]; 3143 for (i = 0; i < dtv[1]; i++) { 3144 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3145 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3146 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3147 } 3148 } 3149 } else { 3150 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3151 tls[0] = dtv; 3152 dtv[0] = tls_dtv_generation; 3153 dtv[1] = tls_max_index; 3154 3155 for (obj = objs; obj; obj = obj->next) { 3156 if (obj->tlsoffset > 0) { 3157 addr = (Elf_Addr)tls + obj->tlsoffset; 3158 if (obj->tlsinitsize > 0) 3159 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3160 if (obj->tlssize > obj->tlsinitsize) 3161 memset((void*) (addr + obj->tlsinitsize), 0, 3162 obj->tlssize - obj->tlsinitsize); 3163 dtv[obj->tlsindex + 1] = addr; 3164 } 3165 } 3166 } 3167 3168 return (tcb); 3169 } 3170 3171 void 3172 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3173 { 3174 Elf_Addr *dtv; 3175 Elf_Addr tlsstart, tlsend; 3176 int dtvsize, i; 3177 3178 assert(tcbsize >= TLS_TCB_SIZE); 3179 3180 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3181 tlsend = tlsstart + tls_static_space; 3182 3183 dtv = *(Elf_Addr **)tlsstart; 3184 dtvsize = dtv[1]; 3185 for (i = 0; i < dtvsize; i++) { 3186 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3187 free((void*)dtv[i+2]); 3188 } 3189 } 3190 free(dtv); 3191 free(tcb); 3192 } 3193 3194 #endif 3195 3196 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3197 defined(__arm__) || defined(__mips__) 3198 3199 /* 3200 * Allocate Static TLS using the Variant II method. 3201 */ 3202 void * 3203 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3204 { 3205 Obj_Entry *obj; 3206 size_t size; 3207 char *tls; 3208 Elf_Addr *dtv, *olddtv; 3209 Elf_Addr segbase, oldsegbase, addr; 3210 int i; 3211 3212 size = round(tls_static_space, tcbalign); 3213 3214 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3215 tls = calloc(1, size + tcbsize); 3216 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3217 3218 segbase = (Elf_Addr)(tls + size); 3219 ((Elf_Addr*)segbase)[0] = segbase; 3220 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3221 3222 dtv[0] = tls_dtv_generation; 3223 dtv[1] = tls_max_index; 3224 3225 if (oldtls) { 3226 /* 3227 * Copy the static TLS block over whole. 3228 */ 3229 oldsegbase = (Elf_Addr) oldtls; 3230 memcpy((void *)(segbase - tls_static_space), 3231 (const void *)(oldsegbase - tls_static_space), 3232 tls_static_space); 3233 3234 /* 3235 * If any dynamic TLS blocks have been created tls_get_addr(), 3236 * move them over. 3237 */ 3238 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3239 for (i = 0; i < olddtv[1]; i++) { 3240 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3241 dtv[i+2] = olddtv[i+2]; 3242 olddtv[i+2] = 0; 3243 } 3244 } 3245 3246 /* 3247 * We assume that this block was the one we created with 3248 * allocate_initial_tls(). 3249 */ 3250 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3251 } else { 3252 for (obj = objs; obj; obj = obj->next) { 3253 if (obj->tlsoffset) { 3254 addr = segbase - obj->tlsoffset; 3255 memset((void*) (addr + obj->tlsinitsize), 3256 0, obj->tlssize - obj->tlsinitsize); 3257 if (obj->tlsinit) 3258 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3259 dtv[obj->tlsindex + 1] = addr; 3260 } 3261 } 3262 } 3263 3264 return (void*) segbase; 3265 } 3266 3267 void 3268 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3269 { 3270 size_t size; 3271 Elf_Addr* dtv; 3272 int dtvsize, i; 3273 Elf_Addr tlsstart, tlsend; 3274 3275 /* 3276 * Figure out the size of the initial TLS block so that we can 3277 * find stuff which ___tls_get_addr() allocated dynamically. 3278 */ 3279 size = round(tls_static_space, tcbalign); 3280 3281 dtv = ((Elf_Addr**)tls)[1]; 3282 dtvsize = dtv[1]; 3283 tlsend = (Elf_Addr) tls; 3284 tlsstart = tlsend - size; 3285 for (i = 0; i < dtvsize; i++) { 3286 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3287 free((void*) dtv[i+2]); 3288 } 3289 } 3290 3291 free((void*) tlsstart); 3292 free((void*) dtv); 3293 } 3294 3295 #endif 3296 3297 /* 3298 * Allocate TLS block for module with given index. 3299 */ 3300 void * 3301 allocate_module_tls(int index) 3302 { 3303 Obj_Entry* obj; 3304 char* p; 3305 3306 for (obj = obj_list; obj; obj = obj->next) { 3307 if (obj->tlsindex == index) 3308 break; 3309 } 3310 if (!obj) { 3311 _rtld_error("Can't find module with TLS index %d", index); 3312 die(); 3313 } 3314 3315 p = malloc(obj->tlssize); 3316 if (p == NULL) { 3317 _rtld_error("Cannot allocate TLS block for index %d", index); 3318 die(); 3319 } 3320 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3321 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3322 3323 return p; 3324 } 3325 3326 bool 3327 allocate_tls_offset(Obj_Entry *obj) 3328 { 3329 size_t off; 3330 3331 if (obj->tls_done) 3332 return true; 3333 3334 if (obj->tlssize == 0) { 3335 obj->tls_done = true; 3336 return true; 3337 } 3338 3339 if (obj->tlsindex == 1) 3340 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3341 else 3342 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3343 obj->tlssize, obj->tlsalign); 3344 3345 /* 3346 * If we have already fixed the size of the static TLS block, we 3347 * must stay within that size. When allocating the static TLS, we 3348 * leave a small amount of space spare to be used for dynamically 3349 * loading modules which use static TLS. 3350 */ 3351 if (tls_static_space) { 3352 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3353 return false; 3354 } 3355 3356 tls_last_offset = obj->tlsoffset = off; 3357 tls_last_size = obj->tlssize; 3358 obj->tls_done = true; 3359 3360 return true; 3361 } 3362 3363 void 3364 free_tls_offset(Obj_Entry *obj) 3365 { 3366 3367 /* 3368 * If we were the last thing to allocate out of the static TLS 3369 * block, we give our space back to the 'allocator'. This is a 3370 * simplistic workaround to allow libGL.so.1 to be loaded and 3371 * unloaded multiple times. 3372 */ 3373 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3374 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3375 tls_last_offset -= obj->tlssize; 3376 tls_last_size = 0; 3377 } 3378 } 3379 3380 void * 3381 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3382 { 3383 void *ret; 3384 int lockstate; 3385 3386 lockstate = wlock_acquire(rtld_bind_lock); 3387 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3388 wlock_release(rtld_bind_lock, lockstate); 3389 return (ret); 3390 } 3391 3392 void 3393 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3394 { 3395 int lockstate; 3396 3397 lockstate = wlock_acquire(rtld_bind_lock); 3398 free_tls(tcb, tcbsize, tcbalign); 3399 wlock_release(rtld_bind_lock, lockstate); 3400 } 3401 3402 static void 3403 object_add_name(Obj_Entry *obj, const char *name) 3404 { 3405 Name_Entry *entry; 3406 size_t len; 3407 3408 len = strlen(name); 3409 entry = malloc(sizeof(Name_Entry) + len); 3410 3411 if (entry != NULL) { 3412 strcpy(entry->name, name); 3413 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3414 } 3415 } 3416 3417 static int 3418 object_match_name(const Obj_Entry *obj, const char *name) 3419 { 3420 Name_Entry *entry; 3421 3422 STAILQ_FOREACH(entry, &obj->names, link) { 3423 if (strcmp(name, entry->name) == 0) 3424 return (1); 3425 } 3426 return (0); 3427 } 3428 3429 static Obj_Entry * 3430 locate_dependency(const Obj_Entry *obj, const char *name) 3431 { 3432 const Objlist_Entry *entry; 3433 const Needed_Entry *needed; 3434 3435 STAILQ_FOREACH(entry, &list_main, link) { 3436 if (object_match_name(entry->obj, name)) 3437 return entry->obj; 3438 } 3439 3440 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3441 if (needed->obj == NULL) 3442 continue; 3443 if (object_match_name(needed->obj, name)) 3444 return needed->obj; 3445 } 3446 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3447 obj->path, name); 3448 die(); 3449 } 3450 3451 static int 3452 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3453 const Elf_Vernaux *vna) 3454 { 3455 const Elf_Verdef *vd; 3456 const char *vername; 3457 3458 vername = refobj->strtab + vna->vna_name; 3459 vd = depobj->verdef; 3460 if (vd == NULL) { 3461 _rtld_error("%s: version %s required by %s not defined", 3462 depobj->path, vername, refobj->path); 3463 return (-1); 3464 } 3465 for (;;) { 3466 if (vd->vd_version != VER_DEF_CURRENT) { 3467 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3468 depobj->path, vd->vd_version); 3469 return (-1); 3470 } 3471 if (vna->vna_hash == vd->vd_hash) { 3472 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3473 ((char *)vd + vd->vd_aux); 3474 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3475 return (0); 3476 } 3477 if (vd->vd_next == 0) 3478 break; 3479 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3480 } 3481 if (vna->vna_flags & VER_FLG_WEAK) 3482 return (0); 3483 _rtld_error("%s: version %s required by %s not found", 3484 depobj->path, vername, refobj->path); 3485 return (-1); 3486 } 3487 3488 static int 3489 rtld_verify_object_versions(Obj_Entry *obj) 3490 { 3491 const Elf_Verneed *vn; 3492 const Elf_Verdef *vd; 3493 const Elf_Verdaux *vda; 3494 const Elf_Vernaux *vna; 3495 const Obj_Entry *depobj; 3496 int maxvernum, vernum; 3497 3498 maxvernum = 0; 3499 /* 3500 * Walk over defined and required version records and figure out 3501 * max index used by any of them. Do very basic sanity checking 3502 * while there. 3503 */ 3504 vn = obj->verneed; 3505 while (vn != NULL) { 3506 if (vn->vn_version != VER_NEED_CURRENT) { 3507 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3508 obj->path, vn->vn_version); 3509 return (-1); 3510 } 3511 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3512 for (;;) { 3513 vernum = VER_NEED_IDX(vna->vna_other); 3514 if (vernum > maxvernum) 3515 maxvernum = vernum; 3516 if (vna->vna_next == 0) 3517 break; 3518 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3519 } 3520 if (vn->vn_next == 0) 3521 break; 3522 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3523 } 3524 3525 vd = obj->verdef; 3526 while (vd != NULL) { 3527 if (vd->vd_version != VER_DEF_CURRENT) { 3528 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3529 obj->path, vd->vd_version); 3530 return (-1); 3531 } 3532 vernum = VER_DEF_IDX(vd->vd_ndx); 3533 if (vernum > maxvernum) 3534 maxvernum = vernum; 3535 if (vd->vd_next == 0) 3536 break; 3537 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3538 } 3539 3540 if (maxvernum == 0) 3541 return (0); 3542 3543 /* 3544 * Store version information in array indexable by version index. 3545 * Verify that object version requirements are satisfied along the 3546 * way. 3547 */ 3548 obj->vernum = maxvernum + 1; 3549 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3550 3551 vd = obj->verdef; 3552 while (vd != NULL) { 3553 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3554 vernum = VER_DEF_IDX(vd->vd_ndx); 3555 assert(vernum <= maxvernum); 3556 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3557 obj->vertab[vernum].hash = vd->vd_hash; 3558 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3559 obj->vertab[vernum].file = NULL; 3560 obj->vertab[vernum].flags = 0; 3561 } 3562 if (vd->vd_next == 0) 3563 break; 3564 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3565 } 3566 3567 vn = obj->verneed; 3568 while (vn != NULL) { 3569 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3570 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3571 for (;;) { 3572 if (check_object_provided_version(obj, depobj, vna)) 3573 return (-1); 3574 vernum = VER_NEED_IDX(vna->vna_other); 3575 assert(vernum <= maxvernum); 3576 obj->vertab[vernum].hash = vna->vna_hash; 3577 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3578 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3579 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3580 VER_INFO_HIDDEN : 0; 3581 if (vna->vna_next == 0) 3582 break; 3583 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3584 } 3585 if (vn->vn_next == 0) 3586 break; 3587 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3588 } 3589 return 0; 3590 } 3591 3592 static int 3593 rtld_verify_versions(const Objlist *objlist) 3594 { 3595 Objlist_Entry *entry; 3596 int rc; 3597 3598 rc = 0; 3599 STAILQ_FOREACH(entry, objlist, link) { 3600 /* 3601 * Skip dummy objects or objects that have their version requirements 3602 * already checked. 3603 */ 3604 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3605 continue; 3606 if (rtld_verify_object_versions(entry->obj) == -1) { 3607 rc = -1; 3608 if (ld_tracing == NULL) 3609 break; 3610 } 3611 } 3612 if (rc == 0 || ld_tracing != NULL) 3613 rc = rtld_verify_object_versions(&obj_rtld); 3614 return rc; 3615 } 3616 3617 const Ver_Entry * 3618 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3619 { 3620 Elf_Versym vernum; 3621 3622 if (obj->vertab) { 3623 vernum = VER_NDX(obj->versyms[symnum]); 3624 if (vernum >= obj->vernum) { 3625 _rtld_error("%s: symbol %s has wrong verneed value %d", 3626 obj->path, obj->strtab + symnum, vernum); 3627 } else if (obj->vertab[vernum].hash != 0) { 3628 return &obj->vertab[vernum]; 3629 } 3630 } 3631 return NULL; 3632 } 3633