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 *); 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 *); 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 unsetenv(LD_ "PRELOAD"); 370 unsetenv(LD_ "LIBMAP"); 371 unsetenv(LD_ "LIBRARY_PATH"); 372 unsetenv(LD_ "LIBMAP_DISABLE"); 373 unsetenv(LD_ "DEBUG"); 374 unsetenv(LD_ "ELF_HINTS_PATH"); 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) == -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_1_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_ORIGIN) && trust) 936 obj->z_origin = true; 937 if (dynp->d_un.d_val & DF_1_GLOBAL) 938 /* XXX */; 939 if (dynp->d_un.d_val & DF_1_BIND_NOW) 940 obj->bind_now = true; 941 if (dynp->d_un.d_val & DF_1_NODELETE) 942 obj->z_nodelete = true; 943 break; 944 945 default: 946 if (!early) { 947 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 948 (long)dynp->d_tag); 949 } 950 break; 951 } 952 } 953 954 obj->traced = false; 955 956 if (plttype == DT_RELA) { 957 obj->pltrela = (const Elf_Rela *) obj->pltrel; 958 obj->pltrel = NULL; 959 obj->pltrelasize = obj->pltrelsize; 960 obj->pltrelsize = 0; 961 } 962 963 if (obj->z_origin && obj->origin_path == NULL) { 964 obj->origin_path = xmalloc(PATH_MAX); 965 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 966 die(); 967 } 968 969 if (dyn_rpath != NULL) { 970 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 971 if (obj->z_origin) 972 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 973 } 974 975 if (dyn_soname != NULL) 976 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 977 } 978 979 /* 980 * Process a shared object's program header. This is used only for the 981 * main program, when the kernel has already loaded the main program 982 * into memory before calling the dynamic linker. It creates and 983 * returns an Obj_Entry structure. 984 */ 985 static Obj_Entry * 986 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 987 { 988 Obj_Entry *obj; 989 const Elf_Phdr *phlimit = phdr + phnum; 990 const Elf_Phdr *ph; 991 int nsegs = 0; 992 993 obj = obj_new(); 994 for (ph = phdr; ph < phlimit; ph++) { 995 if (ph->p_type != PT_PHDR) 996 continue; 997 998 obj->phdr = phdr; 999 obj->phsize = ph->p_memsz; 1000 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1001 break; 1002 } 1003 1004 for (ph = phdr; ph < phlimit; ph++) { 1005 switch (ph->p_type) { 1006 1007 case PT_INTERP: 1008 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1009 break; 1010 1011 case PT_LOAD: 1012 if (nsegs == 0) { /* First load segment */ 1013 obj->vaddrbase = trunc_page(ph->p_vaddr); 1014 obj->mapbase = obj->vaddrbase + obj->relocbase; 1015 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1016 obj->vaddrbase; 1017 } else { /* Last load segment */ 1018 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1019 obj->vaddrbase; 1020 } 1021 nsegs++; 1022 break; 1023 1024 case PT_DYNAMIC: 1025 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1026 break; 1027 1028 case PT_TLS: 1029 obj->tlsindex = 1; 1030 obj->tlssize = ph->p_memsz; 1031 obj->tlsalign = ph->p_align; 1032 obj->tlsinitsize = ph->p_filesz; 1033 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1034 break; 1035 } 1036 } 1037 if (nsegs < 1) { 1038 _rtld_error("%s: too few PT_LOAD segments", path); 1039 return NULL; 1040 } 1041 1042 obj->entry = entry; 1043 return obj; 1044 } 1045 1046 static Obj_Entry * 1047 dlcheck(void *handle) 1048 { 1049 Obj_Entry *obj; 1050 1051 for (obj = obj_list; obj != NULL; obj = obj->next) 1052 if (obj == (Obj_Entry *) handle) 1053 break; 1054 1055 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1056 _rtld_error("Invalid shared object handle %p", handle); 1057 return NULL; 1058 } 1059 return obj; 1060 } 1061 1062 /* 1063 * If the given object is already in the donelist, return true. Otherwise 1064 * add the object to the list and return false. 1065 */ 1066 static bool 1067 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1068 { 1069 unsigned int i; 1070 1071 for (i = 0; i < dlp->num_used; i++) 1072 if (dlp->objs[i] == obj) 1073 return true; 1074 /* 1075 * Our donelist allocation should always be sufficient. But if 1076 * our threads locking isn't working properly, more shared objects 1077 * could have been loaded since we allocated the list. That should 1078 * never happen, but we'll handle it properly just in case it does. 1079 */ 1080 if (dlp->num_used < dlp->num_alloc) 1081 dlp->objs[dlp->num_used++] = obj; 1082 return false; 1083 } 1084 1085 /* 1086 * Hash function for symbol table lookup. Don't even think about changing 1087 * this. It is specified by the System V ABI. 1088 */ 1089 unsigned long 1090 elf_hash(const char *name) 1091 { 1092 const unsigned char *p = (const unsigned char *) name; 1093 unsigned long h = 0; 1094 unsigned long g; 1095 1096 while (*p != '\0') { 1097 h = (h << 4) + *p++; 1098 if ((g = h & 0xf0000000) != 0) 1099 h ^= g >> 24; 1100 h &= ~g; 1101 } 1102 return h; 1103 } 1104 1105 /* 1106 * Find the library with the given name, and return its full pathname. 1107 * The returned string is dynamically allocated. Generates an error 1108 * message and returns NULL if the library cannot be found. 1109 * 1110 * If the second argument is non-NULL, then it refers to an already- 1111 * loaded shared object, whose library search path will be searched. 1112 * 1113 * The search order is: 1114 * LD_LIBRARY_PATH 1115 * rpath in the referencing file 1116 * ldconfig hints 1117 * /lib:/usr/lib 1118 */ 1119 static char * 1120 find_library(const char *xname, const Obj_Entry *refobj) 1121 { 1122 char *pathname; 1123 char *name; 1124 1125 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1126 if (xname[0] != '/' && !trust) { 1127 _rtld_error("Absolute pathname required for shared object \"%s\"", 1128 xname); 1129 return NULL; 1130 } 1131 if (refobj != NULL && refobj->z_origin) 1132 return origin_subst(xname, refobj->origin_path); 1133 else 1134 return xstrdup(xname); 1135 } 1136 1137 if (libmap_disable || (refobj == NULL) || 1138 (name = lm_find(refobj->path, xname)) == NULL) 1139 name = (char *)xname; 1140 1141 dbg(" Searching for \"%s\"", name); 1142 1143 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1144 (refobj != NULL && 1145 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1146 (pathname = search_library_path(name, gethints())) != NULL || 1147 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1148 return pathname; 1149 1150 if(refobj != NULL && refobj->path != NULL) { 1151 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1152 name, basename(refobj->path)); 1153 } else { 1154 _rtld_error("Shared object \"%s\" not found", name); 1155 } 1156 return NULL; 1157 } 1158 1159 /* 1160 * Given a symbol number in a referencing object, find the corresponding 1161 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1162 * no definition was found. Returns a pointer to the Obj_Entry of the 1163 * defining object via the reference parameter DEFOBJ_OUT. 1164 */ 1165 const Elf_Sym * 1166 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1167 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1168 { 1169 const Elf_Sym *ref; 1170 const Elf_Sym *def; 1171 const Obj_Entry *defobj; 1172 const Ver_Entry *ventry; 1173 const char *name; 1174 unsigned long hash; 1175 1176 /* 1177 * If we have already found this symbol, get the information from 1178 * the cache. 1179 */ 1180 if (symnum >= refobj->nchains) 1181 return NULL; /* Bad object */ 1182 if (cache != NULL && cache[symnum].sym != NULL) { 1183 *defobj_out = cache[symnum].obj; 1184 return cache[symnum].sym; 1185 } 1186 1187 ref = refobj->symtab + symnum; 1188 name = refobj->strtab + ref->st_name; 1189 defobj = NULL; 1190 1191 /* 1192 * We don't have to do a full scale lookup if the symbol is local. 1193 * We know it will bind to the instance in this load module; to 1194 * which we already have a pointer (ie ref). By not doing a lookup, 1195 * we not only improve performance, but it also avoids unresolvable 1196 * symbols when local symbols are not in the hash table. This has 1197 * been seen with the ia64 toolchain. 1198 */ 1199 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1200 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1201 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1202 symnum); 1203 } 1204 ventry = fetch_ventry(refobj, symnum); 1205 hash = elf_hash(name); 1206 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1207 } else { 1208 def = ref; 1209 defobj = refobj; 1210 } 1211 1212 /* 1213 * If we found no definition and the reference is weak, treat the 1214 * symbol as having the value zero. 1215 */ 1216 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1217 def = &sym_zero; 1218 defobj = obj_main; 1219 } 1220 1221 if (def != NULL) { 1222 *defobj_out = defobj; 1223 /* Record the information in the cache to avoid subsequent lookups. */ 1224 if (cache != NULL) { 1225 cache[symnum].sym = def; 1226 cache[symnum].obj = defobj; 1227 } 1228 } else { 1229 if (refobj != &obj_rtld) 1230 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1231 } 1232 return def; 1233 } 1234 1235 /* 1236 * Return the search path from the ldconfig hints file, reading it if 1237 * necessary. Returns NULL if there are problems with the hints file, 1238 * or if the search path there is empty. 1239 */ 1240 static const char * 1241 gethints(void) 1242 { 1243 static char *hints; 1244 1245 if (hints == NULL) { 1246 int fd; 1247 struct elfhints_hdr hdr; 1248 char *p; 1249 1250 /* Keep from trying again in case the hints file is bad. */ 1251 hints = ""; 1252 1253 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1254 return NULL; 1255 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1256 hdr.magic != ELFHINTS_MAGIC || 1257 hdr.version != 1) { 1258 close(fd); 1259 return NULL; 1260 } 1261 p = xmalloc(hdr.dirlistlen + 1); 1262 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1263 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1264 free(p); 1265 close(fd); 1266 return NULL; 1267 } 1268 hints = p; 1269 close(fd); 1270 } 1271 return hints[0] != '\0' ? hints : NULL; 1272 } 1273 1274 static void 1275 init_dag(Obj_Entry *root) 1276 { 1277 DoneList donelist; 1278 1279 donelist_init(&donelist); 1280 init_dag1(root, root, &donelist); 1281 } 1282 1283 static void 1284 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1285 { 1286 const Needed_Entry *needed; 1287 1288 if (donelist_check(dlp, obj)) 1289 return; 1290 1291 obj->refcount++; 1292 objlist_push_tail(&obj->dldags, root); 1293 objlist_push_tail(&root->dagmembers, obj); 1294 for (needed = obj->needed; needed != NULL; needed = needed->next) 1295 if (needed->obj != NULL) 1296 init_dag1(root, needed->obj, dlp); 1297 } 1298 1299 /* 1300 * Initialize the dynamic linker. The argument is the address at which 1301 * the dynamic linker has been mapped into memory. The primary task of 1302 * this function is to relocate the dynamic linker. 1303 */ 1304 static void 1305 init_rtld(caddr_t mapbase) 1306 { 1307 Obj_Entry objtmp; /* Temporary rtld object */ 1308 1309 /* 1310 * Conjure up an Obj_Entry structure for the dynamic linker. 1311 * 1312 * The "path" member can't be initialized yet because string constants 1313 * cannot yet be accessed. Below we will set it correctly. 1314 */ 1315 memset(&objtmp, 0, sizeof(objtmp)); 1316 objtmp.path = NULL; 1317 objtmp.rtld = true; 1318 objtmp.mapbase = mapbase; 1319 #ifdef PIC 1320 objtmp.relocbase = mapbase; 1321 #endif 1322 if (RTLD_IS_DYNAMIC()) { 1323 objtmp.dynamic = rtld_dynamic(&objtmp); 1324 digest_dynamic(&objtmp, 1); 1325 assert(objtmp.needed == NULL); 1326 #if !defined(__mips__) 1327 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1328 assert(!objtmp.textrel); 1329 #endif 1330 1331 /* 1332 * Temporarily put the dynamic linker entry into the object list, so 1333 * that symbols can be found. 1334 */ 1335 1336 relocate_objects(&objtmp, true, &objtmp); 1337 } 1338 1339 /* Initialize the object list. */ 1340 obj_tail = &obj_list; 1341 1342 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1343 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1344 1345 /* Replace the path with a dynamically allocated copy. */ 1346 obj_rtld.path = xstrdup(PATH_RTLD); 1347 1348 r_debug.r_brk = r_debug_state; 1349 r_debug.r_state = RT_CONSISTENT; 1350 } 1351 1352 /* 1353 * Add the init functions from a needed object list (and its recursive 1354 * needed objects) to "list". This is not used directly; it is a helper 1355 * function for initlist_add_objects(). The write lock must be held 1356 * when this function is called. 1357 */ 1358 static void 1359 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1360 { 1361 /* Recursively process the successor needed objects. */ 1362 if (needed->next != NULL) 1363 initlist_add_neededs(needed->next, list); 1364 1365 /* Process the current needed object. */ 1366 if (needed->obj != NULL) 1367 initlist_add_objects(needed->obj, &needed->obj->next, list); 1368 } 1369 1370 /* 1371 * Scan all of the DAGs rooted in the range of objects from "obj" to 1372 * "tail" and add their init functions to "list". This recurses over 1373 * the DAGs and ensure the proper init ordering such that each object's 1374 * needed libraries are initialized before the object itself. At the 1375 * same time, this function adds the objects to the global finalization 1376 * list "list_fini" in the opposite order. The write lock must be 1377 * held when this function is called. 1378 */ 1379 static void 1380 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1381 { 1382 if (obj->init_scanned || obj->init_done) 1383 return; 1384 obj->init_scanned = true; 1385 1386 /* Recursively process the successor objects. */ 1387 if (&obj->next != tail) 1388 initlist_add_objects(obj->next, tail, list); 1389 1390 /* Recursively process the needed objects. */ 1391 if (obj->needed != NULL) 1392 initlist_add_neededs(obj->needed, list); 1393 1394 /* Add the object to the init list. */ 1395 if (obj->init != (Elf_Addr)NULL) 1396 objlist_push_tail(list, obj); 1397 1398 /* Add the object to the global fini list in the reverse order. */ 1399 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1400 objlist_push_head(&list_fini, obj); 1401 obj->on_fini_list = true; 1402 } 1403 } 1404 1405 #ifndef FPTR_TARGET 1406 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1407 #endif 1408 1409 static bool 1410 is_exported(const Elf_Sym *def) 1411 { 1412 Elf_Addr value; 1413 const func_ptr_type *p; 1414 1415 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1416 for (p = exports; *p != NULL; p++) 1417 if (FPTR_TARGET(*p) == value) 1418 return true; 1419 return false; 1420 } 1421 1422 /* 1423 * Given a shared object, traverse its list of needed objects, and load 1424 * each of them. Returns 0 on success. Generates an error message and 1425 * returns -1 on failure. 1426 */ 1427 static int 1428 load_needed_objects(Obj_Entry *first) 1429 { 1430 Obj_Entry *obj, *obj1; 1431 1432 for (obj = first; obj != NULL; obj = obj->next) { 1433 Needed_Entry *needed; 1434 1435 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1436 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1437 false); 1438 if (obj1 == NULL && !ld_tracing) 1439 return -1; 1440 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1441 dbg("obj %s nodelete", obj1->path); 1442 init_dag(obj1); 1443 ref_dag(obj1); 1444 obj1->ref_nodel = true; 1445 } 1446 } 1447 } 1448 1449 return 0; 1450 } 1451 1452 static int 1453 load_preload_objects(void) 1454 { 1455 char *p = ld_preload; 1456 static const char delim[] = " \t:;"; 1457 1458 if (p == NULL) 1459 return 0; 1460 1461 p += strspn(p, delim); 1462 while (*p != '\0') { 1463 size_t len = strcspn(p, delim); 1464 char savech; 1465 1466 savech = p[len]; 1467 p[len] = '\0'; 1468 if (load_object(p, NULL, false) == NULL) 1469 return -1; /* XXX - cleanup */ 1470 p[len] = savech; 1471 p += len; 1472 p += strspn(p, delim); 1473 } 1474 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1475 return 0; 1476 } 1477 1478 /* 1479 * Load a shared object into memory, if it is not already loaded. 1480 * 1481 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1482 * on failure. 1483 */ 1484 static Obj_Entry * 1485 load_object(const char *name, const Obj_Entry *refobj, int noload) 1486 { 1487 Obj_Entry *obj; 1488 int fd = -1; 1489 struct stat sb; 1490 char *path; 1491 1492 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1493 if (object_match_name(obj, name)) 1494 return obj; 1495 1496 path = find_library(name, refobj); 1497 if (path == NULL) 1498 return NULL; 1499 1500 /* 1501 * If we didn't find a match by pathname, open the file and check 1502 * again by device and inode. This avoids false mismatches caused 1503 * by multiple links or ".." in pathnames. 1504 * 1505 * To avoid a race, we open the file and use fstat() rather than 1506 * using stat(). 1507 */ 1508 if ((fd = open(path, O_RDONLY)) == -1) { 1509 _rtld_error("Cannot open \"%s\"", path); 1510 free(path); 1511 return NULL; 1512 } 1513 if (fstat(fd, &sb) == -1) { 1514 _rtld_error("Cannot fstat \"%s\"", path); 1515 close(fd); 1516 free(path); 1517 return NULL; 1518 } 1519 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1520 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1521 close(fd); 1522 break; 1523 } 1524 } 1525 if (obj != NULL) { 1526 object_add_name(obj, name); 1527 free(path); 1528 close(fd); 1529 return obj; 1530 } 1531 if (noload) 1532 return (NULL); 1533 1534 /* First use of this object, so we must map it in */ 1535 obj = do_load_object(fd, name, path, &sb); 1536 if (obj == NULL) 1537 free(path); 1538 close(fd); 1539 1540 return obj; 1541 } 1542 1543 static Obj_Entry * 1544 do_load_object(int fd, const char *name, char *path, struct stat *sbp) 1545 { 1546 Obj_Entry *obj; 1547 struct statfs fs; 1548 1549 /* 1550 * but first, make sure that environment variables haven't been 1551 * used to circumvent the noexec flag on a filesystem. 1552 */ 1553 if (dangerous_ld_env) { 1554 if (fstatfs(fd, &fs) != 0) { 1555 _rtld_error("Cannot fstatfs \"%s\"", path); 1556 return NULL; 1557 } 1558 if (fs.f_flags & MNT_NOEXEC) { 1559 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1560 return NULL; 1561 } 1562 } 1563 dbg("loading \"%s\"", path); 1564 obj = map_object(fd, path, sbp); 1565 if (obj == NULL) 1566 return NULL; 1567 1568 object_add_name(obj, name); 1569 obj->path = path; 1570 digest_dynamic(obj, 0); 1571 1572 *obj_tail = obj; 1573 obj_tail = &obj->next; 1574 obj_count++; 1575 obj_loads++; 1576 linkmap_add(obj); /* for GDB & dlinfo() */ 1577 1578 dbg(" %p .. %p: %s", obj->mapbase, 1579 obj->mapbase + obj->mapsize - 1, obj->path); 1580 if (obj->textrel) 1581 dbg(" WARNING: %s has impure text", obj->path); 1582 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1583 obj->path); 1584 1585 return obj; 1586 } 1587 1588 static Obj_Entry * 1589 obj_from_addr(const void *addr) 1590 { 1591 Obj_Entry *obj; 1592 1593 for (obj = obj_list; obj != NULL; obj = obj->next) { 1594 if (addr < (void *) obj->mapbase) 1595 continue; 1596 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1597 return obj; 1598 } 1599 return NULL; 1600 } 1601 1602 /* 1603 * Call the finalization functions for each of the objects in "list" 1604 * which are unreferenced. All of the objects are expected to have 1605 * non-NULL fini functions. 1606 */ 1607 static void 1608 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1609 { 1610 Objlist_Entry *elm, *elm_tmp; 1611 char *saved_msg; 1612 1613 /* 1614 * Preserve the current error message since a fini function might 1615 * call into the dynamic linker and overwrite it. 1616 */ 1617 saved_msg = errmsg_save(); 1618 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1619 if (elm->obj->refcount == 0 || force) { 1620 dbg("calling fini function for %s at %p", elm->obj->path, 1621 (void *)elm->obj->fini); 1622 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1623 elm->obj->path); 1624 /* Remove object from fini list to prevent recursive invocation. */ 1625 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1626 wlock_release(rtld_bind_lock, *lockstate); 1627 call_initfini_pointer(elm->obj, elm->obj->fini); 1628 *lockstate = wlock_acquire(rtld_bind_lock); 1629 /* No need to free anything if process is going down. */ 1630 if (!force) 1631 free(elm); 1632 } 1633 } 1634 errmsg_restore(saved_msg); 1635 } 1636 1637 /* 1638 * Call the initialization functions for each of the objects in 1639 * "list". All of the objects are expected to have non-NULL init 1640 * functions. 1641 */ 1642 static void 1643 objlist_call_init(Objlist *list, int *lockstate) 1644 { 1645 Objlist_Entry *elm; 1646 Obj_Entry *obj; 1647 char *saved_msg; 1648 1649 /* 1650 * Clean init_scanned flag so that objects can be rechecked and 1651 * possibly initialized earlier if any of vectors called below 1652 * cause the change by using dlopen. 1653 */ 1654 for (obj = obj_list; obj != NULL; obj = obj->next) 1655 obj->init_scanned = false; 1656 1657 /* 1658 * Preserve the current error message since an init function might 1659 * call into the dynamic linker and overwrite it. 1660 */ 1661 saved_msg = errmsg_save(); 1662 STAILQ_FOREACH(elm, list, link) { 1663 if (elm->obj->init_done) /* Initialized early. */ 1664 continue; 1665 dbg("calling init function for %s at %p", elm->obj->path, 1666 (void *)elm->obj->init); 1667 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1668 elm->obj->path); 1669 /* 1670 * Race: other thread might try to use this object before current 1671 * one completes the initilization. Not much can be done here 1672 * without better locking. 1673 */ 1674 elm->obj->init_done = true; 1675 wlock_release(rtld_bind_lock, *lockstate); 1676 call_initfini_pointer(elm->obj, elm->obj->init); 1677 *lockstate = wlock_acquire(rtld_bind_lock); 1678 } 1679 errmsg_restore(saved_msg); 1680 } 1681 1682 static void 1683 objlist_clear(Objlist *list) 1684 { 1685 Objlist_Entry *elm; 1686 1687 while (!STAILQ_EMPTY(list)) { 1688 elm = STAILQ_FIRST(list); 1689 STAILQ_REMOVE_HEAD(list, link); 1690 free(elm); 1691 } 1692 } 1693 1694 static Objlist_Entry * 1695 objlist_find(Objlist *list, const Obj_Entry *obj) 1696 { 1697 Objlist_Entry *elm; 1698 1699 STAILQ_FOREACH(elm, list, link) 1700 if (elm->obj == obj) 1701 return elm; 1702 return NULL; 1703 } 1704 1705 static void 1706 objlist_init(Objlist *list) 1707 { 1708 STAILQ_INIT(list); 1709 } 1710 1711 static void 1712 objlist_push_head(Objlist *list, Obj_Entry *obj) 1713 { 1714 Objlist_Entry *elm; 1715 1716 elm = NEW(Objlist_Entry); 1717 elm->obj = obj; 1718 STAILQ_INSERT_HEAD(list, elm, link); 1719 } 1720 1721 static void 1722 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1723 { 1724 Objlist_Entry *elm; 1725 1726 elm = NEW(Objlist_Entry); 1727 elm->obj = obj; 1728 STAILQ_INSERT_TAIL(list, elm, link); 1729 } 1730 1731 static void 1732 objlist_remove(Objlist *list, Obj_Entry *obj) 1733 { 1734 Objlist_Entry *elm; 1735 1736 if ((elm = objlist_find(list, obj)) != NULL) { 1737 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1738 free(elm); 1739 } 1740 } 1741 1742 /* 1743 * Relocate newly-loaded shared objects. The argument is a pointer to 1744 * the Obj_Entry for the first such object. All objects from the first 1745 * to the end of the list of objects are relocated. Returns 0 on success, 1746 * or -1 on failure. 1747 */ 1748 static int 1749 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1750 { 1751 Obj_Entry *obj; 1752 1753 for (obj = first; obj != NULL; obj = obj->next) { 1754 if (obj != rtldobj) 1755 dbg("relocating \"%s\"", obj->path); 1756 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1757 obj->symtab == NULL || obj->strtab == NULL) { 1758 _rtld_error("%s: Shared object has no run-time symbol table", 1759 obj->path); 1760 return -1; 1761 } 1762 1763 if (obj->textrel) { 1764 /* There are relocations to the write-protected text segment. */ 1765 if (mprotect(obj->mapbase, obj->textsize, 1766 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1767 _rtld_error("%s: Cannot write-enable text segment: %s", 1768 obj->path, strerror(errno)); 1769 return -1; 1770 } 1771 } 1772 1773 /* Process the non-PLT relocations. */ 1774 if (reloc_non_plt(obj, rtldobj)) 1775 return -1; 1776 1777 if (obj->textrel) { /* Re-protected the text segment. */ 1778 if (mprotect(obj->mapbase, obj->textsize, 1779 PROT_READ|PROT_EXEC) == -1) { 1780 _rtld_error("%s: Cannot write-protect text segment: %s", 1781 obj->path, strerror(errno)); 1782 return -1; 1783 } 1784 } 1785 1786 /* Process the PLT relocations. */ 1787 if (reloc_plt(obj) == -1) 1788 return -1; 1789 /* Relocate the jump slots if we are doing immediate binding. */ 1790 if (obj->bind_now || bind_now) 1791 if (reloc_jmpslots(obj) == -1) 1792 return -1; 1793 1794 1795 /* 1796 * Set up the magic number and version in the Obj_Entry. These 1797 * were checked in the crt1.o from the original ElfKit, so we 1798 * set them for backward compatibility. 1799 */ 1800 obj->magic = RTLD_MAGIC; 1801 obj->version = RTLD_VERSION; 1802 1803 /* Set the special PLT or GOT entries. */ 1804 init_pltgot(obj); 1805 } 1806 1807 return 0; 1808 } 1809 1810 /* 1811 * Cleanup procedure. It will be called (by the atexit mechanism) just 1812 * before the process exits. 1813 */ 1814 static void 1815 rtld_exit(void) 1816 { 1817 int lockstate; 1818 1819 lockstate = wlock_acquire(rtld_bind_lock); 1820 dbg("rtld_exit()"); 1821 objlist_call_fini(&list_fini, true, &lockstate); 1822 /* No need to remove the items from the list, since we are exiting. */ 1823 if (!libmap_disable) 1824 lm_fini(); 1825 wlock_release(rtld_bind_lock, lockstate); 1826 } 1827 1828 static void * 1829 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1830 { 1831 #ifdef COMPAT_32BIT 1832 const char *trans; 1833 #endif 1834 if (path == NULL) 1835 return (NULL); 1836 1837 path += strspn(path, ":;"); 1838 while (*path != '\0') { 1839 size_t len; 1840 char *res; 1841 1842 len = strcspn(path, ":;"); 1843 #ifdef COMPAT_32BIT 1844 trans = lm_findn(NULL, path, len); 1845 if (trans) 1846 res = callback(trans, strlen(trans), arg); 1847 else 1848 #endif 1849 res = callback(path, len, arg); 1850 1851 if (res != NULL) 1852 return (res); 1853 1854 path += len; 1855 path += strspn(path, ":;"); 1856 } 1857 1858 return (NULL); 1859 } 1860 1861 struct try_library_args { 1862 const char *name; 1863 size_t namelen; 1864 char *buffer; 1865 size_t buflen; 1866 }; 1867 1868 static void * 1869 try_library_path(const char *dir, size_t dirlen, void *param) 1870 { 1871 struct try_library_args *arg; 1872 1873 arg = param; 1874 if (*dir == '/' || trust) { 1875 char *pathname; 1876 1877 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1878 return (NULL); 1879 1880 pathname = arg->buffer; 1881 strncpy(pathname, dir, dirlen); 1882 pathname[dirlen] = '/'; 1883 strcpy(pathname + dirlen + 1, arg->name); 1884 1885 dbg(" Trying \"%s\"", pathname); 1886 if (access(pathname, F_OK) == 0) { /* We found it */ 1887 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1888 strcpy(pathname, arg->buffer); 1889 return (pathname); 1890 } 1891 } 1892 return (NULL); 1893 } 1894 1895 static char * 1896 search_library_path(const char *name, const char *path) 1897 { 1898 char *p; 1899 struct try_library_args arg; 1900 1901 if (path == NULL) 1902 return NULL; 1903 1904 arg.name = name; 1905 arg.namelen = strlen(name); 1906 arg.buffer = xmalloc(PATH_MAX); 1907 arg.buflen = PATH_MAX; 1908 1909 p = path_enumerate(path, try_library_path, &arg); 1910 1911 free(arg.buffer); 1912 1913 return (p); 1914 } 1915 1916 int 1917 dlclose(void *handle) 1918 { 1919 Obj_Entry *root; 1920 int lockstate; 1921 1922 lockstate = wlock_acquire(rtld_bind_lock); 1923 root = dlcheck(handle); 1924 if (root == NULL) { 1925 wlock_release(rtld_bind_lock, lockstate); 1926 return -1; 1927 } 1928 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1929 root->path); 1930 1931 /* Unreference the object and its dependencies. */ 1932 root->dl_refcount--; 1933 1934 unref_dag(root); 1935 1936 if (root->refcount == 0) { 1937 /* 1938 * The object is no longer referenced, so we must unload it. 1939 * First, call the fini functions. 1940 */ 1941 objlist_call_fini(&list_fini, false, &lockstate); 1942 1943 /* Finish cleaning up the newly-unreferenced objects. */ 1944 GDB_STATE(RT_DELETE,&root->linkmap); 1945 unload_object(root); 1946 GDB_STATE(RT_CONSISTENT,NULL); 1947 } 1948 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1949 wlock_release(rtld_bind_lock, lockstate); 1950 return 0; 1951 } 1952 1953 const char * 1954 dlerror(void) 1955 { 1956 char *msg = error_message; 1957 error_message = NULL; 1958 return msg; 1959 } 1960 1961 /* 1962 * This function is deprecated and has no effect. 1963 */ 1964 void 1965 dllockinit(void *context, 1966 void *(*lock_create)(void *context), 1967 void (*rlock_acquire)(void *lock), 1968 void (*wlock_acquire)(void *lock), 1969 void (*lock_release)(void *lock), 1970 void (*lock_destroy)(void *lock), 1971 void (*context_destroy)(void *context)) 1972 { 1973 static void *cur_context; 1974 static void (*cur_context_destroy)(void *); 1975 1976 /* Just destroy the context from the previous call, if necessary. */ 1977 if (cur_context_destroy != NULL) 1978 cur_context_destroy(cur_context); 1979 cur_context = context; 1980 cur_context_destroy = context_destroy; 1981 } 1982 1983 void * 1984 dlopen(const char *name, int mode) 1985 { 1986 Obj_Entry **old_obj_tail; 1987 Obj_Entry *obj; 1988 Objlist initlist; 1989 int result, lockstate, nodelete, noload; 1990 1991 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 1992 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1993 if (ld_tracing != NULL) 1994 environ = (char **)*get_program_var_addr("environ"); 1995 nodelete = mode & RTLD_NODELETE; 1996 noload = mode & RTLD_NOLOAD; 1997 1998 objlist_init(&initlist); 1999 2000 lockstate = wlock_acquire(rtld_bind_lock); 2001 GDB_STATE(RT_ADD,NULL); 2002 2003 old_obj_tail = obj_tail; 2004 obj = NULL; 2005 if (name == NULL) { 2006 obj = obj_main; 2007 obj->refcount++; 2008 } else { 2009 obj = load_object(name, obj_main, noload); 2010 } 2011 2012 if (obj) { 2013 obj->dl_refcount++; 2014 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2015 objlist_push_tail(&list_global, obj); 2016 mode &= RTLD_MODEMASK; 2017 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2018 assert(*old_obj_tail == obj); 2019 result = load_needed_objects(obj); 2020 init_dag(obj); 2021 if (result != -1) 2022 result = rtld_verify_versions(&obj->dagmembers); 2023 if (result != -1 && ld_tracing) 2024 goto trace; 2025 if (result == -1 || 2026 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2027 obj->dl_refcount--; 2028 unref_dag(obj); 2029 if (obj->refcount == 0) 2030 unload_object(obj); 2031 obj = NULL; 2032 } else { 2033 /* Make list of init functions to call. */ 2034 initlist_add_objects(obj, &obj->next, &initlist); 2035 } 2036 } else { 2037 2038 /* Bump the reference counts for objects on this DAG. */ 2039 ref_dag(obj); 2040 2041 if (ld_tracing) 2042 goto trace; 2043 } 2044 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2045 dbg("obj %s nodelete", obj->path); 2046 ref_dag(obj); 2047 obj->z_nodelete = obj->ref_nodel = true; 2048 } 2049 } 2050 2051 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2052 name); 2053 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2054 2055 /* Call the init functions. */ 2056 objlist_call_init(&initlist, &lockstate); 2057 objlist_clear(&initlist); 2058 wlock_release(rtld_bind_lock, lockstate); 2059 return obj; 2060 trace: 2061 trace_loaded_objects(obj); 2062 wlock_release(rtld_bind_lock, lockstate); 2063 exit(0); 2064 } 2065 2066 static void * 2067 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2068 int flags) 2069 { 2070 DoneList donelist; 2071 const Obj_Entry *obj, *defobj; 2072 const Elf_Sym *def, *symp; 2073 unsigned long hash; 2074 int lockstate; 2075 2076 hash = elf_hash(name); 2077 def = NULL; 2078 defobj = NULL; 2079 flags |= SYMLOOK_IN_PLT; 2080 2081 lockstate = rlock_acquire(rtld_bind_lock); 2082 if (handle == NULL || handle == RTLD_NEXT || 2083 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2084 2085 if ((obj = obj_from_addr(retaddr)) == NULL) { 2086 _rtld_error("Cannot determine caller's shared object"); 2087 rlock_release(rtld_bind_lock, lockstate); 2088 return NULL; 2089 } 2090 if (handle == NULL) { /* Just the caller's shared object. */ 2091 def = symlook_obj(name, hash, obj, ve, flags); 2092 defobj = obj; 2093 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2094 handle == RTLD_SELF) { /* ... caller included */ 2095 if (handle == RTLD_NEXT) 2096 obj = obj->next; 2097 for (; obj != NULL; obj = obj->next) { 2098 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2099 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2100 def = symp; 2101 defobj = obj; 2102 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2103 break; 2104 } 2105 } 2106 } 2107 /* 2108 * Search the dynamic linker itself, and possibly resolve the 2109 * symbol from there. This is how the application links to 2110 * dynamic linker services such as dlopen. Only the values listed 2111 * in the "exports" array can be resolved from the dynamic linker. 2112 */ 2113 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2114 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2115 if (symp != NULL && is_exported(symp)) { 2116 def = symp; 2117 defobj = &obj_rtld; 2118 } 2119 } 2120 } else { 2121 assert(handle == RTLD_DEFAULT); 2122 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2123 } 2124 } else { 2125 if ((obj = dlcheck(handle)) == NULL) { 2126 rlock_release(rtld_bind_lock, lockstate); 2127 return NULL; 2128 } 2129 2130 donelist_init(&donelist); 2131 if (obj->mainprog) { 2132 /* Search main program and all libraries loaded by it. */ 2133 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2134 &donelist); 2135 2136 /* 2137 * We do not distinguish between 'main' object and global scope. 2138 * If symbol is not defined by objects loaded at startup, continue 2139 * search among dynamically loaded objects with RTLD_GLOBAL 2140 * scope. 2141 */ 2142 if (def == NULL) 2143 def = symlook_list(name, hash, &list_global, &defobj, ve, 2144 flags, &donelist); 2145 } else { 2146 Needed_Entry fake; 2147 2148 /* Search the whole DAG rooted at the given object. */ 2149 fake.next = NULL; 2150 fake.obj = (Obj_Entry *)obj; 2151 fake.name = 0; 2152 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2153 &donelist); 2154 } 2155 } 2156 2157 if (def != NULL) { 2158 rlock_release(rtld_bind_lock, lockstate); 2159 2160 /* 2161 * The value required by the caller is derived from the value 2162 * of the symbol. For the ia64 architecture, we need to 2163 * construct a function descriptor which the caller can use to 2164 * call the function with the right 'gp' value. For other 2165 * architectures and for non-functions, the value is simply 2166 * the relocated value of the symbol. 2167 */ 2168 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2169 return make_function_pointer(def, defobj); 2170 else 2171 return defobj->relocbase + def->st_value; 2172 } 2173 2174 _rtld_error("Undefined symbol \"%s\"", name); 2175 rlock_release(rtld_bind_lock, lockstate); 2176 return NULL; 2177 } 2178 2179 void * 2180 dlsym(void *handle, const char *name) 2181 { 2182 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2183 SYMLOOK_DLSYM); 2184 } 2185 2186 dlfunc_t 2187 dlfunc(void *handle, const char *name) 2188 { 2189 union { 2190 void *d; 2191 dlfunc_t f; 2192 } rv; 2193 2194 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2195 SYMLOOK_DLSYM); 2196 return (rv.f); 2197 } 2198 2199 void * 2200 dlvsym(void *handle, const char *name, const char *version) 2201 { 2202 Ver_Entry ventry; 2203 2204 ventry.name = version; 2205 ventry.file = NULL; 2206 ventry.hash = elf_hash(version); 2207 ventry.flags= 0; 2208 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2209 SYMLOOK_DLSYM); 2210 } 2211 2212 int 2213 dladdr(const void *addr, Dl_info *info) 2214 { 2215 const Obj_Entry *obj; 2216 const Elf_Sym *def; 2217 void *symbol_addr; 2218 unsigned long symoffset; 2219 int lockstate; 2220 2221 lockstate = rlock_acquire(rtld_bind_lock); 2222 obj = obj_from_addr(addr); 2223 if (obj == NULL) { 2224 _rtld_error("No shared object contains address"); 2225 rlock_release(rtld_bind_lock, lockstate); 2226 return 0; 2227 } 2228 info->dli_fname = obj->path; 2229 info->dli_fbase = obj->mapbase; 2230 info->dli_saddr = (void *)0; 2231 info->dli_sname = NULL; 2232 2233 /* 2234 * Walk the symbol list looking for the symbol whose address is 2235 * closest to the address sent in. 2236 */ 2237 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2238 def = obj->symtab + symoffset; 2239 2240 /* 2241 * For skip the symbol if st_shndx is either SHN_UNDEF or 2242 * SHN_COMMON. 2243 */ 2244 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2245 continue; 2246 2247 /* 2248 * If the symbol is greater than the specified address, or if it 2249 * is further away from addr than the current nearest symbol, 2250 * then reject it. 2251 */ 2252 symbol_addr = obj->relocbase + def->st_value; 2253 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2254 continue; 2255 2256 /* Update our idea of the nearest symbol. */ 2257 info->dli_sname = obj->strtab + def->st_name; 2258 info->dli_saddr = symbol_addr; 2259 2260 /* Exact match? */ 2261 if (info->dli_saddr == addr) 2262 break; 2263 } 2264 rlock_release(rtld_bind_lock, lockstate); 2265 return 1; 2266 } 2267 2268 int 2269 dlinfo(void *handle, int request, void *p) 2270 { 2271 const Obj_Entry *obj; 2272 int error, lockstate; 2273 2274 lockstate = rlock_acquire(rtld_bind_lock); 2275 2276 if (handle == NULL || handle == RTLD_SELF) { 2277 void *retaddr; 2278 2279 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2280 if ((obj = obj_from_addr(retaddr)) == NULL) 2281 _rtld_error("Cannot determine caller's shared object"); 2282 } else 2283 obj = dlcheck(handle); 2284 2285 if (obj == NULL) { 2286 rlock_release(rtld_bind_lock, lockstate); 2287 return (-1); 2288 } 2289 2290 error = 0; 2291 switch (request) { 2292 case RTLD_DI_LINKMAP: 2293 *((struct link_map const **)p) = &obj->linkmap; 2294 break; 2295 case RTLD_DI_ORIGIN: 2296 error = rtld_dirname(obj->path, p); 2297 break; 2298 2299 case RTLD_DI_SERINFOSIZE: 2300 case RTLD_DI_SERINFO: 2301 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2302 break; 2303 2304 default: 2305 _rtld_error("Invalid request %d passed to dlinfo()", request); 2306 error = -1; 2307 } 2308 2309 rlock_release(rtld_bind_lock, lockstate); 2310 2311 return (error); 2312 } 2313 2314 int 2315 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2316 { 2317 struct dl_phdr_info phdr_info; 2318 const Obj_Entry *obj; 2319 int error, bind_lockstate, phdr_lockstate; 2320 2321 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2322 bind_lockstate = rlock_acquire(rtld_bind_lock); 2323 2324 error = 0; 2325 2326 for (obj = obj_list; obj != NULL; obj = obj->next) { 2327 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2328 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2329 STAILQ_FIRST(&obj->names)->name : obj->path; 2330 phdr_info.dlpi_phdr = obj->phdr; 2331 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2332 phdr_info.dlpi_tls_modid = obj->tlsindex; 2333 phdr_info.dlpi_tls_data = obj->tlsinit; 2334 phdr_info.dlpi_adds = obj_loads; 2335 phdr_info.dlpi_subs = obj_loads - obj_count; 2336 2337 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2338 break; 2339 2340 } 2341 rlock_release(rtld_bind_lock, bind_lockstate); 2342 wlock_release(rtld_phdr_lock, phdr_lockstate); 2343 2344 return (error); 2345 } 2346 2347 struct fill_search_info_args { 2348 int request; 2349 unsigned int flags; 2350 Dl_serinfo *serinfo; 2351 Dl_serpath *serpath; 2352 char *strspace; 2353 }; 2354 2355 static void * 2356 fill_search_info(const char *dir, size_t dirlen, void *param) 2357 { 2358 struct fill_search_info_args *arg; 2359 2360 arg = param; 2361 2362 if (arg->request == RTLD_DI_SERINFOSIZE) { 2363 arg->serinfo->dls_cnt ++; 2364 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2365 } else { 2366 struct dl_serpath *s_entry; 2367 2368 s_entry = arg->serpath; 2369 s_entry->dls_name = arg->strspace; 2370 s_entry->dls_flags = arg->flags; 2371 2372 strncpy(arg->strspace, dir, dirlen); 2373 arg->strspace[dirlen] = '\0'; 2374 2375 arg->strspace += dirlen + 1; 2376 arg->serpath++; 2377 } 2378 2379 return (NULL); 2380 } 2381 2382 static int 2383 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2384 { 2385 struct dl_serinfo _info; 2386 struct fill_search_info_args args; 2387 2388 args.request = RTLD_DI_SERINFOSIZE; 2389 args.serinfo = &_info; 2390 2391 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2392 _info.dls_cnt = 0; 2393 2394 path_enumerate(ld_library_path, fill_search_info, &args); 2395 path_enumerate(obj->rpath, fill_search_info, &args); 2396 path_enumerate(gethints(), fill_search_info, &args); 2397 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2398 2399 2400 if (request == RTLD_DI_SERINFOSIZE) { 2401 info->dls_size = _info.dls_size; 2402 info->dls_cnt = _info.dls_cnt; 2403 return (0); 2404 } 2405 2406 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2407 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2408 return (-1); 2409 } 2410 2411 args.request = RTLD_DI_SERINFO; 2412 args.serinfo = info; 2413 args.serpath = &info->dls_serpath[0]; 2414 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2415 2416 args.flags = LA_SER_LIBPATH; 2417 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2418 return (-1); 2419 2420 args.flags = LA_SER_RUNPATH; 2421 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2422 return (-1); 2423 2424 args.flags = LA_SER_CONFIG; 2425 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2426 return (-1); 2427 2428 args.flags = LA_SER_DEFAULT; 2429 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2430 return (-1); 2431 return (0); 2432 } 2433 2434 static int 2435 rtld_dirname(const char *path, char *bname) 2436 { 2437 const char *endp; 2438 2439 /* Empty or NULL string gets treated as "." */ 2440 if (path == NULL || *path == '\0') { 2441 bname[0] = '.'; 2442 bname[1] = '\0'; 2443 return (0); 2444 } 2445 2446 /* Strip trailing slashes */ 2447 endp = path + strlen(path) - 1; 2448 while (endp > path && *endp == '/') 2449 endp--; 2450 2451 /* Find the start of the dir */ 2452 while (endp > path && *endp != '/') 2453 endp--; 2454 2455 /* Either the dir is "/" or there are no slashes */ 2456 if (endp == path) { 2457 bname[0] = *endp == '/' ? '/' : '.'; 2458 bname[1] = '\0'; 2459 return (0); 2460 } else { 2461 do { 2462 endp--; 2463 } while (endp > path && *endp == '/'); 2464 } 2465 2466 if (endp - path + 2 > PATH_MAX) 2467 { 2468 _rtld_error("Filename is too long: %s", path); 2469 return(-1); 2470 } 2471 2472 strncpy(bname, path, endp - path + 1); 2473 bname[endp - path + 1] = '\0'; 2474 return (0); 2475 } 2476 2477 static int 2478 rtld_dirname_abs(const char *path, char *base) 2479 { 2480 char base_rel[PATH_MAX]; 2481 2482 if (rtld_dirname(path, base) == -1) 2483 return (-1); 2484 if (base[0] == '/') 2485 return (0); 2486 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2487 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2488 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2489 return (-1); 2490 strcpy(base, base_rel); 2491 return (0); 2492 } 2493 2494 static void 2495 linkmap_add(Obj_Entry *obj) 2496 { 2497 struct link_map *l = &obj->linkmap; 2498 struct link_map *prev; 2499 2500 obj->linkmap.l_name = obj->path; 2501 obj->linkmap.l_addr = obj->mapbase; 2502 obj->linkmap.l_ld = obj->dynamic; 2503 #ifdef __mips__ 2504 /* GDB needs load offset on MIPS to use the symbols */ 2505 obj->linkmap.l_offs = obj->relocbase; 2506 #endif 2507 2508 if (r_debug.r_map == NULL) { 2509 r_debug.r_map = l; 2510 return; 2511 } 2512 2513 /* 2514 * Scan to the end of the list, but not past the entry for the 2515 * dynamic linker, which we want to keep at the very end. 2516 */ 2517 for (prev = r_debug.r_map; 2518 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2519 prev = prev->l_next) 2520 ; 2521 2522 /* Link in the new entry. */ 2523 l->l_prev = prev; 2524 l->l_next = prev->l_next; 2525 if (l->l_next != NULL) 2526 l->l_next->l_prev = l; 2527 prev->l_next = l; 2528 } 2529 2530 static void 2531 linkmap_delete(Obj_Entry *obj) 2532 { 2533 struct link_map *l = &obj->linkmap; 2534 2535 if (l->l_prev == NULL) { 2536 if ((r_debug.r_map = l->l_next) != NULL) 2537 l->l_next->l_prev = NULL; 2538 return; 2539 } 2540 2541 if ((l->l_prev->l_next = l->l_next) != NULL) 2542 l->l_next->l_prev = l->l_prev; 2543 } 2544 2545 /* 2546 * Function for the debugger to set a breakpoint on to gain control. 2547 * 2548 * The two parameters allow the debugger to easily find and determine 2549 * what the runtime loader is doing and to whom it is doing it. 2550 * 2551 * When the loadhook trap is hit (r_debug_state, set at program 2552 * initialization), the arguments can be found on the stack: 2553 * 2554 * +8 struct link_map *m 2555 * +4 struct r_debug *rd 2556 * +0 RetAddr 2557 */ 2558 void 2559 r_debug_state(struct r_debug* rd, struct link_map *m) 2560 { 2561 } 2562 2563 /* 2564 * Get address of the pointer variable in the main program. 2565 */ 2566 static const void ** 2567 get_program_var_addr(const char *name) 2568 { 2569 const Obj_Entry *obj; 2570 unsigned long hash; 2571 2572 hash = elf_hash(name); 2573 for (obj = obj_main; obj != NULL; obj = obj->next) { 2574 const Elf_Sym *def; 2575 2576 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2577 const void **addr; 2578 2579 addr = (const void **)(obj->relocbase + def->st_value); 2580 return addr; 2581 } 2582 } 2583 return NULL; 2584 } 2585 2586 /* 2587 * Set a pointer variable in the main program to the given value. This 2588 * is used to set key variables such as "environ" before any of the 2589 * init functions are called. 2590 */ 2591 static void 2592 set_program_var(const char *name, const void *value) 2593 { 2594 const void **addr; 2595 2596 if ((addr = get_program_var_addr(name)) != NULL) { 2597 dbg("\"%s\": *%p <-- %p", name, addr, value); 2598 *addr = value; 2599 } 2600 } 2601 2602 /* 2603 * Given a symbol name in a referencing object, find the corresponding 2604 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2605 * no definition was found. Returns a pointer to the Obj_Entry of the 2606 * defining object via the reference parameter DEFOBJ_OUT. 2607 */ 2608 static const Elf_Sym * 2609 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2610 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2611 { 2612 DoneList donelist; 2613 const Elf_Sym *def; 2614 const Elf_Sym *symp; 2615 const Obj_Entry *obj; 2616 const Obj_Entry *defobj; 2617 const Objlist_Entry *elm; 2618 def = NULL; 2619 defobj = NULL; 2620 donelist_init(&donelist); 2621 2622 /* Look first in the referencing object if linked symbolically. */ 2623 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2624 symp = symlook_obj(name, hash, refobj, ventry, flags); 2625 if (symp != NULL) { 2626 def = symp; 2627 defobj = refobj; 2628 } 2629 } 2630 2631 /* Search all objects loaded at program start up. */ 2632 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2633 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2634 &donelist); 2635 if (symp != NULL && 2636 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2637 def = symp; 2638 defobj = obj; 2639 } 2640 } 2641 2642 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2643 STAILQ_FOREACH(elm, &list_global, link) { 2644 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2645 break; 2646 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2647 flags, &donelist); 2648 if (symp != NULL && 2649 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2650 def = symp; 2651 defobj = obj; 2652 } 2653 } 2654 2655 /* Search all dlopened DAGs containing the referencing object. */ 2656 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2657 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2658 break; 2659 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2660 flags, &donelist); 2661 if (symp != NULL && 2662 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2663 def = symp; 2664 defobj = obj; 2665 } 2666 } 2667 2668 /* 2669 * Search the dynamic linker itself, and possibly resolve the 2670 * symbol from there. This is how the application links to 2671 * dynamic linker services such as dlopen. Only the values listed 2672 * in the "exports" array can be resolved from the dynamic linker. 2673 */ 2674 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2675 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2676 if (symp != NULL && is_exported(symp)) { 2677 def = symp; 2678 defobj = &obj_rtld; 2679 } 2680 } 2681 2682 if (def != NULL) 2683 *defobj_out = defobj; 2684 return def; 2685 } 2686 2687 static const Elf_Sym * 2688 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2689 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2690 DoneList *dlp) 2691 { 2692 const Elf_Sym *symp; 2693 const Elf_Sym *def; 2694 const Obj_Entry *defobj; 2695 const Objlist_Entry *elm; 2696 2697 def = NULL; 2698 defobj = NULL; 2699 STAILQ_FOREACH(elm, objlist, link) { 2700 if (donelist_check(dlp, elm->obj)) 2701 continue; 2702 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2703 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2704 def = symp; 2705 defobj = elm->obj; 2706 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2707 break; 2708 } 2709 } 2710 } 2711 if (def != NULL) 2712 *defobj_out = defobj; 2713 return def; 2714 } 2715 2716 /* 2717 * Search the symbol table of a shared object and all objects needed 2718 * by it for a symbol of the given name. Search order is 2719 * breadth-first. Returns a pointer to the symbol, or NULL if no 2720 * definition was found. 2721 */ 2722 static const Elf_Sym * 2723 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2724 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2725 DoneList *dlp) 2726 { 2727 const Elf_Sym *def, *def_w; 2728 const Needed_Entry *n; 2729 const Obj_Entry *obj, *defobj, *defobj1; 2730 2731 def = def_w = NULL; 2732 defobj = NULL; 2733 for (n = needed; n != NULL; n = n->next) { 2734 if ((obj = n->obj) == NULL || 2735 donelist_check(dlp, obj) || 2736 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2737 continue; 2738 defobj = obj; 2739 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2740 *defobj_out = defobj; 2741 return (def); 2742 } 2743 } 2744 /* 2745 * There we come when either symbol definition is not found in 2746 * directly needed objects, or found symbol is weak. 2747 */ 2748 for (n = needed; n != NULL; n = n->next) { 2749 if ((obj = n->obj) == NULL) 2750 continue; 2751 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2752 ventry, flags, dlp); 2753 if (def_w == NULL) 2754 continue; 2755 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2756 def = def_w; 2757 defobj = defobj1; 2758 } 2759 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2760 break; 2761 } 2762 if (def != NULL) 2763 *defobj_out = defobj; 2764 return (def); 2765 } 2766 2767 /* 2768 * Search the symbol table of a single shared object for a symbol of 2769 * the given name and version, if requested. Returns a pointer to the 2770 * symbol, or NULL if no definition was found. 2771 * 2772 * The symbol's hash value is passed in for efficiency reasons; that 2773 * eliminates many recomputations of the hash value. 2774 */ 2775 const Elf_Sym * 2776 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2777 const Ver_Entry *ventry, int flags) 2778 { 2779 unsigned long symnum; 2780 const Elf_Sym *vsymp; 2781 Elf_Versym verndx; 2782 int vcount; 2783 2784 if (obj->buckets == NULL) 2785 return NULL; 2786 2787 vsymp = NULL; 2788 vcount = 0; 2789 symnum = obj->buckets[hash % obj->nbuckets]; 2790 2791 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2792 const Elf_Sym *symp; 2793 const char *strp; 2794 2795 if (symnum >= obj->nchains) 2796 return NULL; /* Bad object */ 2797 2798 symp = obj->symtab + symnum; 2799 strp = obj->strtab + symp->st_name; 2800 2801 switch (ELF_ST_TYPE(symp->st_info)) { 2802 case STT_FUNC: 2803 case STT_NOTYPE: 2804 case STT_OBJECT: 2805 if (symp->st_value == 0) 2806 continue; 2807 /* fallthrough */ 2808 case STT_TLS: 2809 if (symp->st_shndx != SHN_UNDEF) 2810 break; 2811 #ifndef __mips__ 2812 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2813 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2814 break; 2815 /* fallthrough */ 2816 #endif 2817 default: 2818 continue; 2819 } 2820 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2821 continue; 2822 2823 if (ventry == NULL) { 2824 if (obj->versyms != NULL) { 2825 verndx = VER_NDX(obj->versyms[symnum]); 2826 if (verndx > obj->vernum) { 2827 _rtld_error("%s: symbol %s references wrong version %d", 2828 obj->path, obj->strtab + symnum, verndx); 2829 continue; 2830 } 2831 /* 2832 * If we are not called from dlsym (i.e. this is a normal 2833 * relocation from unversioned binary, accept the symbol 2834 * immediately if it happens to have first version after 2835 * this shared object became versioned. Otherwise, if 2836 * symbol is versioned and not hidden, remember it. If it 2837 * is the only symbol with this name exported by the 2838 * shared object, it will be returned as a match at the 2839 * end of the function. If symbol is global (verndx < 2) 2840 * accept it unconditionally. 2841 */ 2842 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2843 return symp; 2844 else if (verndx >= VER_NDX_GIVEN) { 2845 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2846 if (vsymp == NULL) 2847 vsymp = symp; 2848 vcount ++; 2849 } 2850 continue; 2851 } 2852 } 2853 return symp; 2854 } else { 2855 if (obj->versyms == NULL) { 2856 if (object_match_name(obj, ventry->name)) { 2857 _rtld_error("%s: object %s should provide version %s for " 2858 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2859 obj->strtab + symnum); 2860 continue; 2861 } 2862 } else { 2863 verndx = VER_NDX(obj->versyms[symnum]); 2864 if (verndx > obj->vernum) { 2865 _rtld_error("%s: symbol %s references wrong version %d", 2866 obj->path, obj->strtab + symnum, verndx); 2867 continue; 2868 } 2869 if (obj->vertab[verndx].hash != ventry->hash || 2870 strcmp(obj->vertab[verndx].name, ventry->name)) { 2871 /* 2872 * Version does not match. Look if this is a global symbol 2873 * and if it is not hidden. If global symbol (verndx < 2) 2874 * is available, use it. Do not return symbol if we are 2875 * called by dlvsym, because dlvsym looks for a specific 2876 * version and default one is not what dlvsym wants. 2877 */ 2878 if ((flags & SYMLOOK_DLSYM) || 2879 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2880 (verndx >= VER_NDX_GIVEN)) 2881 continue; 2882 } 2883 } 2884 return symp; 2885 } 2886 } 2887 return (vcount == 1) ? vsymp : NULL; 2888 } 2889 2890 static void 2891 trace_loaded_objects(Obj_Entry *obj) 2892 { 2893 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2894 int c; 2895 2896 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2897 main_local = ""; 2898 2899 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2900 fmt1 = "\t%o => %p (%x)\n"; 2901 2902 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2903 fmt2 = "\t%o (%x)\n"; 2904 2905 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2906 2907 for (; obj; obj = obj->next) { 2908 Needed_Entry *needed; 2909 char *name, *path; 2910 bool is_lib; 2911 2912 if (list_containers && obj->needed != NULL) 2913 printf("%s:\n", obj->path); 2914 for (needed = obj->needed; needed; needed = needed->next) { 2915 if (needed->obj != NULL) { 2916 if (needed->obj->traced && !list_containers) 2917 continue; 2918 needed->obj->traced = true; 2919 path = needed->obj->path; 2920 } else 2921 path = "not found"; 2922 2923 name = (char *)obj->strtab + needed->name; 2924 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2925 2926 fmt = is_lib ? fmt1 : fmt2; 2927 while ((c = *fmt++) != '\0') { 2928 switch (c) { 2929 default: 2930 putchar(c); 2931 continue; 2932 case '\\': 2933 switch (c = *fmt) { 2934 case '\0': 2935 continue; 2936 case 'n': 2937 putchar('\n'); 2938 break; 2939 case 't': 2940 putchar('\t'); 2941 break; 2942 } 2943 break; 2944 case '%': 2945 switch (c = *fmt) { 2946 case '\0': 2947 continue; 2948 case '%': 2949 default: 2950 putchar(c); 2951 break; 2952 case 'A': 2953 printf("%s", main_local); 2954 break; 2955 case 'a': 2956 printf("%s", obj_main->path); 2957 break; 2958 case 'o': 2959 printf("%s", name); 2960 break; 2961 #if 0 2962 case 'm': 2963 printf("%d", sodp->sod_major); 2964 break; 2965 case 'n': 2966 printf("%d", sodp->sod_minor); 2967 break; 2968 #endif 2969 case 'p': 2970 printf("%s", path); 2971 break; 2972 case 'x': 2973 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2974 break; 2975 } 2976 break; 2977 } 2978 ++fmt; 2979 } 2980 } 2981 } 2982 } 2983 2984 /* 2985 * Unload a dlopened object and its dependencies from memory and from 2986 * our data structures. It is assumed that the DAG rooted in the 2987 * object has already been unreferenced, and that the object has a 2988 * reference count of 0. 2989 */ 2990 static void 2991 unload_object(Obj_Entry *root) 2992 { 2993 Obj_Entry *obj; 2994 Obj_Entry **linkp; 2995 2996 assert(root->refcount == 0); 2997 2998 /* 2999 * Pass over the DAG removing unreferenced objects from 3000 * appropriate lists. 3001 */ 3002 unlink_object(root); 3003 3004 /* Unmap all objects that are no longer referenced. */ 3005 linkp = &obj_list->next; 3006 while ((obj = *linkp) != NULL) { 3007 if (obj->refcount == 0) { 3008 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3009 obj->path); 3010 dbg("unloading \"%s\"", obj->path); 3011 munmap(obj->mapbase, obj->mapsize); 3012 linkmap_delete(obj); 3013 *linkp = obj->next; 3014 obj_count--; 3015 obj_free(obj); 3016 } else 3017 linkp = &obj->next; 3018 } 3019 obj_tail = linkp; 3020 } 3021 3022 static void 3023 unlink_object(Obj_Entry *root) 3024 { 3025 Objlist_Entry *elm; 3026 3027 if (root->refcount == 0) { 3028 /* Remove the object from the RTLD_GLOBAL list. */ 3029 objlist_remove(&list_global, root); 3030 3031 /* Remove the object from all objects' DAG lists. */ 3032 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3033 objlist_remove(&elm->obj->dldags, root); 3034 if (elm->obj != root) 3035 unlink_object(elm->obj); 3036 } 3037 } 3038 } 3039 3040 static void 3041 ref_dag(Obj_Entry *root) 3042 { 3043 Objlist_Entry *elm; 3044 3045 STAILQ_FOREACH(elm, &root->dagmembers, link) 3046 elm->obj->refcount++; 3047 } 3048 3049 static void 3050 unref_dag(Obj_Entry *root) 3051 { 3052 Objlist_Entry *elm; 3053 3054 STAILQ_FOREACH(elm, &root->dagmembers, link) 3055 elm->obj->refcount--; 3056 } 3057 3058 /* 3059 * Common code for MD __tls_get_addr(). 3060 */ 3061 void * 3062 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3063 { 3064 Elf_Addr* dtv = *dtvp; 3065 int lockstate; 3066 3067 /* Check dtv generation in case new modules have arrived */ 3068 if (dtv[0] != tls_dtv_generation) { 3069 Elf_Addr* newdtv; 3070 int to_copy; 3071 3072 lockstate = wlock_acquire(rtld_bind_lock); 3073 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3074 to_copy = dtv[1]; 3075 if (to_copy > tls_max_index) 3076 to_copy = tls_max_index; 3077 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3078 newdtv[0] = tls_dtv_generation; 3079 newdtv[1] = tls_max_index; 3080 free(dtv); 3081 wlock_release(rtld_bind_lock, lockstate); 3082 *dtvp = newdtv; 3083 } 3084 3085 /* Dynamically allocate module TLS if necessary */ 3086 if (!dtv[index + 1]) { 3087 /* Signal safe, wlock will block out signals. */ 3088 lockstate = wlock_acquire(rtld_bind_lock); 3089 if (!dtv[index + 1]) 3090 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3091 wlock_release(rtld_bind_lock, lockstate); 3092 } 3093 return (void*) (dtv[index + 1] + offset); 3094 } 3095 3096 /* XXX not sure what variants to use for arm. */ 3097 3098 #if defined(__ia64__) || defined(__powerpc__) 3099 3100 /* 3101 * Allocate Static TLS using the Variant I method. 3102 */ 3103 void * 3104 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3105 { 3106 Obj_Entry *obj; 3107 char *tcb; 3108 Elf_Addr **tls; 3109 Elf_Addr *dtv; 3110 Elf_Addr addr; 3111 int i; 3112 3113 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3114 return (oldtcb); 3115 3116 assert(tcbsize >= TLS_TCB_SIZE); 3117 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3118 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3119 3120 if (oldtcb != NULL) { 3121 memcpy(tls, oldtcb, tls_static_space); 3122 free(oldtcb); 3123 3124 /* Adjust the DTV. */ 3125 dtv = tls[0]; 3126 for (i = 0; i < dtv[1]; i++) { 3127 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3128 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3129 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3130 } 3131 } 3132 } else { 3133 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3134 tls[0] = dtv; 3135 dtv[0] = tls_dtv_generation; 3136 dtv[1] = tls_max_index; 3137 3138 for (obj = objs; obj; obj = obj->next) { 3139 if (obj->tlsoffset) { 3140 addr = (Elf_Addr)tls + obj->tlsoffset; 3141 memset((void*) (addr + obj->tlsinitsize), 3142 0, obj->tlssize - obj->tlsinitsize); 3143 if (obj->tlsinit) 3144 memcpy((void*) addr, obj->tlsinit, 3145 obj->tlsinitsize); 3146 dtv[obj->tlsindex + 1] = addr; 3147 } 3148 } 3149 } 3150 3151 return (tcb); 3152 } 3153 3154 void 3155 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3156 { 3157 Elf_Addr *dtv; 3158 Elf_Addr tlsstart, tlsend; 3159 int dtvsize, i; 3160 3161 assert(tcbsize >= TLS_TCB_SIZE); 3162 3163 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3164 tlsend = tlsstart + tls_static_space; 3165 3166 dtv = *(Elf_Addr **)tlsstart; 3167 dtvsize = dtv[1]; 3168 for (i = 0; i < dtvsize; i++) { 3169 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3170 free((void*)dtv[i+2]); 3171 } 3172 } 3173 free(dtv); 3174 free(tcb); 3175 } 3176 3177 #endif 3178 3179 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3180 defined(__arm__) || defined(__mips__) 3181 3182 /* 3183 * Allocate Static TLS using the Variant II method. 3184 */ 3185 void * 3186 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3187 { 3188 Obj_Entry *obj; 3189 size_t size; 3190 char *tls; 3191 Elf_Addr *dtv, *olddtv; 3192 Elf_Addr segbase, oldsegbase, addr; 3193 int i; 3194 3195 size = round(tls_static_space, tcbalign); 3196 3197 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3198 tls = calloc(1, size + tcbsize); 3199 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3200 3201 segbase = (Elf_Addr)(tls + size); 3202 ((Elf_Addr*)segbase)[0] = segbase; 3203 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3204 3205 dtv[0] = tls_dtv_generation; 3206 dtv[1] = tls_max_index; 3207 3208 if (oldtls) { 3209 /* 3210 * Copy the static TLS block over whole. 3211 */ 3212 oldsegbase = (Elf_Addr) oldtls; 3213 memcpy((void *)(segbase - tls_static_space), 3214 (const void *)(oldsegbase - tls_static_space), 3215 tls_static_space); 3216 3217 /* 3218 * If any dynamic TLS blocks have been created tls_get_addr(), 3219 * move them over. 3220 */ 3221 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3222 for (i = 0; i < olddtv[1]; i++) { 3223 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3224 dtv[i+2] = olddtv[i+2]; 3225 olddtv[i+2] = 0; 3226 } 3227 } 3228 3229 /* 3230 * We assume that this block was the one we created with 3231 * allocate_initial_tls(). 3232 */ 3233 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3234 } else { 3235 for (obj = objs; obj; obj = obj->next) { 3236 if (obj->tlsoffset) { 3237 addr = segbase - obj->tlsoffset; 3238 memset((void*) (addr + obj->tlsinitsize), 3239 0, obj->tlssize - obj->tlsinitsize); 3240 if (obj->tlsinit) 3241 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3242 dtv[obj->tlsindex + 1] = addr; 3243 } 3244 } 3245 } 3246 3247 return (void*) segbase; 3248 } 3249 3250 void 3251 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3252 { 3253 size_t size; 3254 Elf_Addr* dtv; 3255 int dtvsize, i; 3256 Elf_Addr tlsstart, tlsend; 3257 3258 /* 3259 * Figure out the size of the initial TLS block so that we can 3260 * find stuff which ___tls_get_addr() allocated dynamically. 3261 */ 3262 size = round(tls_static_space, tcbalign); 3263 3264 dtv = ((Elf_Addr**)tls)[1]; 3265 dtvsize = dtv[1]; 3266 tlsend = (Elf_Addr) tls; 3267 tlsstart = tlsend - size; 3268 for (i = 0; i < dtvsize; i++) { 3269 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3270 free((void*) dtv[i+2]); 3271 } 3272 } 3273 3274 free((void*) tlsstart); 3275 free((void*) dtv); 3276 } 3277 3278 #endif 3279 3280 /* 3281 * Allocate TLS block for module with given index. 3282 */ 3283 void * 3284 allocate_module_tls(int index) 3285 { 3286 Obj_Entry* obj; 3287 char* p; 3288 3289 for (obj = obj_list; obj; obj = obj->next) { 3290 if (obj->tlsindex == index) 3291 break; 3292 } 3293 if (!obj) { 3294 _rtld_error("Can't find module with TLS index %d", index); 3295 die(); 3296 } 3297 3298 p = malloc(obj->tlssize); 3299 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3300 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3301 3302 return p; 3303 } 3304 3305 bool 3306 allocate_tls_offset(Obj_Entry *obj) 3307 { 3308 size_t off; 3309 3310 if (obj->tls_done) 3311 return true; 3312 3313 if (obj->tlssize == 0) { 3314 obj->tls_done = true; 3315 return true; 3316 } 3317 3318 if (obj->tlsindex == 1) 3319 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3320 else 3321 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3322 obj->tlssize, obj->tlsalign); 3323 3324 /* 3325 * If we have already fixed the size of the static TLS block, we 3326 * must stay within that size. When allocating the static TLS, we 3327 * leave a small amount of space spare to be used for dynamically 3328 * loading modules which use static TLS. 3329 */ 3330 if (tls_static_space) { 3331 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3332 return false; 3333 } 3334 3335 tls_last_offset = obj->tlsoffset = off; 3336 tls_last_size = obj->tlssize; 3337 obj->tls_done = true; 3338 3339 return true; 3340 } 3341 3342 void 3343 free_tls_offset(Obj_Entry *obj) 3344 { 3345 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3346 defined(__arm__) || defined(__mips__) 3347 /* 3348 * If we were the last thing to allocate out of the static TLS 3349 * block, we give our space back to the 'allocator'. This is a 3350 * simplistic workaround to allow libGL.so.1 to be loaded and 3351 * unloaded multiple times. We only handle the Variant II 3352 * mechanism for now - this really needs a proper allocator. 3353 */ 3354 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3355 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3356 tls_last_offset -= obj->tlssize; 3357 tls_last_size = 0; 3358 } 3359 #endif 3360 } 3361 3362 void * 3363 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3364 { 3365 void *ret; 3366 int lockstate; 3367 3368 lockstate = wlock_acquire(rtld_bind_lock); 3369 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3370 wlock_release(rtld_bind_lock, lockstate); 3371 return (ret); 3372 } 3373 3374 void 3375 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3376 { 3377 int lockstate; 3378 3379 lockstate = wlock_acquire(rtld_bind_lock); 3380 free_tls(tcb, tcbsize, tcbalign); 3381 wlock_release(rtld_bind_lock, lockstate); 3382 } 3383 3384 static void 3385 object_add_name(Obj_Entry *obj, const char *name) 3386 { 3387 Name_Entry *entry; 3388 size_t len; 3389 3390 len = strlen(name); 3391 entry = malloc(sizeof(Name_Entry) + len); 3392 3393 if (entry != NULL) { 3394 strcpy(entry->name, name); 3395 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3396 } 3397 } 3398 3399 static int 3400 object_match_name(const Obj_Entry *obj, const char *name) 3401 { 3402 Name_Entry *entry; 3403 3404 STAILQ_FOREACH(entry, &obj->names, link) { 3405 if (strcmp(name, entry->name) == 0) 3406 return (1); 3407 } 3408 return (0); 3409 } 3410 3411 static Obj_Entry * 3412 locate_dependency(const Obj_Entry *obj, const char *name) 3413 { 3414 const Objlist_Entry *entry; 3415 const Needed_Entry *needed; 3416 3417 STAILQ_FOREACH(entry, &list_main, link) { 3418 if (object_match_name(entry->obj, name)) 3419 return entry->obj; 3420 } 3421 3422 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3423 if (needed->obj == NULL) 3424 continue; 3425 if (object_match_name(needed->obj, name)) 3426 return needed->obj; 3427 } 3428 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3429 obj->path, name); 3430 die(); 3431 } 3432 3433 static int 3434 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3435 const Elf_Vernaux *vna) 3436 { 3437 const Elf_Verdef *vd; 3438 const char *vername; 3439 3440 vername = refobj->strtab + vna->vna_name; 3441 vd = depobj->verdef; 3442 if (vd == NULL) { 3443 _rtld_error("%s: version %s required by %s not defined", 3444 depobj->path, vername, refobj->path); 3445 return (-1); 3446 } 3447 for (;;) { 3448 if (vd->vd_version != VER_DEF_CURRENT) { 3449 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3450 depobj->path, vd->vd_version); 3451 return (-1); 3452 } 3453 if (vna->vna_hash == vd->vd_hash) { 3454 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3455 ((char *)vd + vd->vd_aux); 3456 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3457 return (0); 3458 } 3459 if (vd->vd_next == 0) 3460 break; 3461 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3462 } 3463 if (vna->vna_flags & VER_FLG_WEAK) 3464 return (0); 3465 _rtld_error("%s: version %s required by %s not found", 3466 depobj->path, vername, refobj->path); 3467 return (-1); 3468 } 3469 3470 static int 3471 rtld_verify_object_versions(Obj_Entry *obj) 3472 { 3473 const Elf_Verneed *vn; 3474 const Elf_Verdef *vd; 3475 const Elf_Verdaux *vda; 3476 const Elf_Vernaux *vna; 3477 const Obj_Entry *depobj; 3478 int maxvernum, vernum; 3479 3480 maxvernum = 0; 3481 /* 3482 * Walk over defined and required version records and figure out 3483 * max index used by any of them. Do very basic sanity checking 3484 * while there. 3485 */ 3486 vn = obj->verneed; 3487 while (vn != NULL) { 3488 if (vn->vn_version != VER_NEED_CURRENT) { 3489 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3490 obj->path, vn->vn_version); 3491 return (-1); 3492 } 3493 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3494 for (;;) { 3495 vernum = VER_NEED_IDX(vna->vna_other); 3496 if (vernum > maxvernum) 3497 maxvernum = vernum; 3498 if (vna->vna_next == 0) 3499 break; 3500 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3501 } 3502 if (vn->vn_next == 0) 3503 break; 3504 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3505 } 3506 3507 vd = obj->verdef; 3508 while (vd != NULL) { 3509 if (vd->vd_version != VER_DEF_CURRENT) { 3510 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3511 obj->path, vd->vd_version); 3512 return (-1); 3513 } 3514 vernum = VER_DEF_IDX(vd->vd_ndx); 3515 if (vernum > maxvernum) 3516 maxvernum = vernum; 3517 if (vd->vd_next == 0) 3518 break; 3519 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3520 } 3521 3522 if (maxvernum == 0) 3523 return (0); 3524 3525 /* 3526 * Store version information in array indexable by version index. 3527 * Verify that object version requirements are satisfied along the 3528 * way. 3529 */ 3530 obj->vernum = maxvernum + 1; 3531 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3532 3533 vd = obj->verdef; 3534 while (vd != NULL) { 3535 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3536 vernum = VER_DEF_IDX(vd->vd_ndx); 3537 assert(vernum <= maxvernum); 3538 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3539 obj->vertab[vernum].hash = vd->vd_hash; 3540 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3541 obj->vertab[vernum].file = NULL; 3542 obj->vertab[vernum].flags = 0; 3543 } 3544 if (vd->vd_next == 0) 3545 break; 3546 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3547 } 3548 3549 vn = obj->verneed; 3550 while (vn != NULL) { 3551 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3552 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3553 for (;;) { 3554 if (check_object_provided_version(obj, depobj, vna)) 3555 return (-1); 3556 vernum = VER_NEED_IDX(vna->vna_other); 3557 assert(vernum <= maxvernum); 3558 obj->vertab[vernum].hash = vna->vna_hash; 3559 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3560 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3561 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3562 VER_INFO_HIDDEN : 0; 3563 if (vna->vna_next == 0) 3564 break; 3565 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3566 } 3567 if (vn->vn_next == 0) 3568 break; 3569 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3570 } 3571 return 0; 3572 } 3573 3574 static int 3575 rtld_verify_versions(const Objlist *objlist) 3576 { 3577 Objlist_Entry *entry; 3578 int rc; 3579 3580 rc = 0; 3581 STAILQ_FOREACH(entry, objlist, link) { 3582 /* 3583 * Skip dummy objects or objects that have their version requirements 3584 * already checked. 3585 */ 3586 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3587 continue; 3588 if (rtld_verify_object_versions(entry->obj) == -1) { 3589 rc = -1; 3590 if (ld_tracing == NULL) 3591 break; 3592 } 3593 } 3594 if (rc == 0 || ld_tracing != NULL) 3595 rc = rtld_verify_object_versions(&obj_rtld); 3596 return rc; 3597 } 3598 3599 const Ver_Entry * 3600 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3601 { 3602 Elf_Versym vernum; 3603 3604 if (obj->vertab) { 3605 vernum = VER_NDX(obj->versyms[symnum]); 3606 if (vernum >= obj->vernum) { 3607 _rtld_error("%s: symbol %s has wrong verneed value %d", 3608 obj->path, obj->strtab + symnum, vernum); 3609 } else if (obj->vertab[vernum].hash != 0) { 3610 return &obj->vertab[vernum]; 3611 } 3612 } 3613 return NULL; 3614 } 3615