1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/sysctl.h> 44 #include <sys/uio.h> 45 #include <sys/utsname.h> 46 #include <sys/ktrace.h> 47 48 #include <dlfcn.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <stdarg.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 #include "debug.h" 59 #include "rtld.h" 60 #include "libmap.h" 61 #include "rtld_tls.h" 62 63 #ifndef COMPAT_32BIT 64 #define PATH_RTLD "/libexec/ld-elf.so.1" 65 #else 66 #define PATH_RTLD "/libexec/ld-elf32.so.1" 67 #endif 68 69 /* Types. */ 70 typedef void (*func_ptr_type)(); 71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73 /* 74 * This structure provides a reentrant way to keep a list of objects and 75 * check which ones have already been processed in some way. 76 */ 77 typedef struct Struct_DoneList { 78 const Obj_Entry **objs; /* Array of object pointers */ 79 unsigned int num_alloc; /* Allocated size of the array */ 80 unsigned int num_used; /* Number of array slots used */ 81 } DoneList; 82 83 /* 84 * Function declarations. 85 */ 86 static const char *basename(const char *); 87 static void die(void) __dead2; 88 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 89 const Elf_Dyn **); 90 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 91 static void digest_dynamic(Obj_Entry *, int); 92 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 93 static Obj_Entry *dlcheck(void *); 94 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 95 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 96 static bool donelist_check(DoneList *, const Obj_Entry *); 97 static void errmsg_restore(char *); 98 static char *errmsg_save(void); 99 static void *fill_search_info(const char *, size_t, void *); 100 static char *find_library(const char *, const Obj_Entry *); 101 static const char *gethints(void); 102 static void init_dag(Obj_Entry *); 103 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 104 static void init_rtld(caddr_t, Elf_Auxinfo **); 105 static void initlist_add_neededs(Needed_Entry *, Objlist *); 106 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 107 static void linkmap_add(Obj_Entry *); 108 static void linkmap_delete(Obj_Entry *); 109 static int load_needed_objects(Obj_Entry *, int); 110 static int load_preload_objects(void); 111 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 112 static Obj_Entry *obj_from_addr(const void *); 113 static void objlist_call_fini(Objlist *, bool, int *); 114 static void objlist_call_init(Objlist *, int *); 115 static void objlist_clear(Objlist *); 116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117 static void objlist_init(Objlist *); 118 static void objlist_push_head(Objlist *, Obj_Entry *); 119 static void objlist_push_tail(Objlist *, Obj_Entry *); 120 static void objlist_remove(Objlist *, Obj_Entry *); 121 static void *path_enumerate(const char *, path_enum_proc, void *); 122 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 123 static int rtld_dirname(const char *, char *); 124 static int rtld_dirname_abs(const char *, char *); 125 static void rtld_exit(void); 126 static char *search_library_path(const char *, const char *); 127 static const void **get_program_var_addr(const char *); 128 static void set_program_var(const char *, const void *); 129 static const Elf_Sym *symlook_default(const char *, unsigned long, 130 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 131 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 132 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 133 static const Elf_Sym *symlook_needed(const char *, unsigned long, 134 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 135 int, DoneList *); 136 static void trace_loaded_objects(Obj_Entry *); 137 static void unlink_object(Obj_Entry *); 138 static void unload_object(Obj_Entry *); 139 static void unref_dag(Obj_Entry *); 140 static void ref_dag(Obj_Entry *); 141 static int origin_subst_one(char **, const char *, const char *, 142 const char *, char *); 143 static char *origin_subst(const char *, const char *); 144 static int rtld_verify_versions(const Objlist *); 145 static int rtld_verify_object_versions(Obj_Entry *); 146 static void object_add_name(Obj_Entry *, const char *); 147 static int object_match_name(const Obj_Entry *, const char *); 148 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 149 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 150 struct dl_phdr_info *phdr_info); 151 152 void r_debug_state(struct r_debug *, struct link_map *); 153 154 /* 155 * Data declarations. 156 */ 157 static char *error_message; /* Message for dlerror(), or NULL */ 158 struct r_debug r_debug; /* for GDB; */ 159 static bool libmap_disable; /* Disable libmap */ 160 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 161 static bool trust; /* False for setuid and setgid programs */ 162 static bool dangerous_ld_env; /* True if environment variables have been 163 used to affect the libraries loaded */ 164 static char *ld_bind_now; /* Environment variable for immediate binding */ 165 static char *ld_debug; /* Environment variable for debugging */ 166 static char *ld_library_path; /* Environment variable for search path */ 167 static char *ld_preload; /* Environment variable for libraries to 168 load first */ 169 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 170 static char *ld_tracing; /* Called from ldd to print libs */ 171 static char *ld_utrace; /* Use utrace() to log events. */ 172 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 173 static Obj_Entry **obj_tail; /* Link field of last object in list */ 174 static Obj_Entry *obj_main; /* The main program shared object */ 175 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 176 static unsigned int obj_count; /* Number of objects in obj_list */ 177 static unsigned int obj_loads; /* Number of objects in obj_list */ 178 179 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 180 STAILQ_HEAD_INITIALIZER(list_global); 181 static Objlist list_main = /* Objects loaded at program startup */ 182 STAILQ_HEAD_INITIALIZER(list_main); 183 static Objlist list_fini = /* Objects needing fini() calls */ 184 STAILQ_HEAD_INITIALIZER(list_fini); 185 186 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 187 188 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 189 190 extern Elf_Dyn _DYNAMIC; 191 #pragma weak _DYNAMIC 192 #ifndef RTLD_IS_DYNAMIC 193 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 194 #endif 195 196 int osreldate, pagesize; 197 198 /* 199 * Global declarations normally provided by crt1. The dynamic linker is 200 * not built with crt1, so we have to provide them ourselves. 201 */ 202 char *__progname; 203 char **environ; 204 205 /* 206 * Globals to control TLS allocation. 207 */ 208 size_t tls_last_offset; /* Static TLS offset of last module */ 209 size_t tls_last_size; /* Static TLS size of last module */ 210 size_t tls_static_space; /* Static TLS space allocated */ 211 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 212 int tls_max_index = 1; /* Largest module index allocated */ 213 214 /* 215 * Fill in a DoneList with an allocation large enough to hold all of 216 * the currently-loaded objects. Keep this as a macro since it calls 217 * alloca and we want that to occur within the scope of the caller. 218 */ 219 #define donelist_init(dlp) \ 220 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 221 assert((dlp)->objs != NULL), \ 222 (dlp)->num_alloc = obj_count, \ 223 (dlp)->num_used = 0) 224 225 #define UTRACE_DLOPEN_START 1 226 #define UTRACE_DLOPEN_STOP 2 227 #define UTRACE_DLCLOSE_START 3 228 #define UTRACE_DLCLOSE_STOP 4 229 #define UTRACE_LOAD_OBJECT 5 230 #define UTRACE_UNLOAD_OBJECT 6 231 #define UTRACE_ADD_RUNDEP 7 232 #define UTRACE_PRELOAD_FINISHED 8 233 #define UTRACE_INIT_CALL 9 234 #define UTRACE_FINI_CALL 10 235 236 struct utrace_rtld { 237 char sig[4]; /* 'RTLD' */ 238 int event; 239 void *handle; 240 void *mapbase; /* Used for 'parent' and 'init/fini' */ 241 size_t mapsize; 242 int refcnt; /* Used for 'mode' */ 243 char name[MAXPATHLEN]; 244 }; 245 246 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 247 if (ld_utrace != NULL) \ 248 ld_utrace_log(e, h, mb, ms, r, n); \ 249 } while (0) 250 251 static void 252 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 253 int refcnt, const char *name) 254 { 255 struct utrace_rtld ut; 256 257 ut.sig[0] = 'R'; 258 ut.sig[1] = 'T'; 259 ut.sig[2] = 'L'; 260 ut.sig[3] = 'D'; 261 ut.event = event; 262 ut.handle = handle; 263 ut.mapbase = mapbase; 264 ut.mapsize = mapsize; 265 ut.refcnt = refcnt; 266 bzero(ut.name, sizeof(ut.name)); 267 if (name) 268 strlcpy(ut.name, name, sizeof(ut.name)); 269 utrace(&ut, sizeof(ut)); 270 } 271 272 /* 273 * Main entry point for dynamic linking. The first argument is the 274 * stack pointer. The stack is expected to be laid out as described 275 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 276 * Specifically, the stack pointer points to a word containing 277 * ARGC. Following that in the stack is a null-terminated sequence 278 * of pointers to argument strings. Then comes a null-terminated 279 * sequence of pointers to environment strings. Finally, there is a 280 * sequence of "auxiliary vector" entries. 281 * 282 * The second argument points to a place to store the dynamic linker's 283 * exit procedure pointer and the third to a place to store the main 284 * program's object. 285 * 286 * The return value is the main program's entry point. 287 */ 288 func_ptr_type 289 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 290 { 291 Elf_Auxinfo *aux_info[AT_COUNT]; 292 int i; 293 int argc; 294 char **argv; 295 char **env; 296 Elf_Auxinfo *aux; 297 Elf_Auxinfo *auxp; 298 const char *argv0; 299 Objlist_Entry *entry; 300 Obj_Entry *obj; 301 Obj_Entry **preload_tail; 302 Objlist initlist; 303 int lockstate; 304 305 /* 306 * On entry, the dynamic linker itself has not been relocated yet. 307 * Be very careful not to reference any global data until after 308 * init_rtld has returned. It is OK to reference file-scope statics 309 * and string constants, and to call static and global functions. 310 */ 311 312 /* Find the auxiliary vector on the stack. */ 313 argc = *sp++; 314 argv = (char **) sp; 315 sp += argc + 1; /* Skip over arguments and NULL terminator */ 316 env = (char **) sp; 317 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 318 ; 319 aux = (Elf_Auxinfo *) sp; 320 321 /* Digest the auxiliary vector. */ 322 for (i = 0; i < AT_COUNT; i++) 323 aux_info[i] = NULL; 324 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 325 if (auxp->a_type < AT_COUNT) 326 aux_info[auxp->a_type] = auxp; 327 } 328 329 /* Initialize and relocate ourselves. */ 330 assert(aux_info[AT_BASE] != NULL); 331 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 332 333 __progname = obj_rtld.path; 334 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 335 environ = env; 336 337 trust = !issetugid(); 338 339 ld_bind_now = getenv(LD_ "BIND_NOW"); 340 /* 341 * If the process is tainted, then we un-set the dangerous environment 342 * variables. The process will be marked as tainted until setuid(2) 343 * is called. If any child process calls setuid(2) we do not want any 344 * future processes to honor the potentially un-safe variables. 345 */ 346 if (!trust) { 347 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 348 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 349 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH")) { 350 _rtld_error("environment corrupt; aborting"); 351 die(); 352 } 353 } 354 ld_debug = getenv(LD_ "DEBUG"); 355 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 356 libmap_override = getenv(LD_ "LIBMAP"); 357 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 358 ld_preload = getenv(LD_ "PRELOAD"); 359 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 360 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 361 (ld_library_path != NULL) || (ld_preload != NULL) || 362 (ld_elf_hints_path != NULL); 363 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 364 ld_utrace = getenv(LD_ "UTRACE"); 365 366 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 367 ld_elf_hints_path = _PATH_ELF_HINTS; 368 369 if (ld_debug != NULL && *ld_debug != '\0') 370 debug = 1; 371 dbg("%s is initialized, base address = %p", __progname, 372 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 373 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 374 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 375 376 /* 377 * Load the main program, or process its program header if it is 378 * already loaded. 379 */ 380 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 381 int fd = aux_info[AT_EXECFD]->a_un.a_val; 382 dbg("loading main program"); 383 obj_main = map_object(fd, argv0, NULL); 384 close(fd); 385 if (obj_main == NULL) 386 die(); 387 } else { /* Main program already loaded. */ 388 const Elf_Phdr *phdr; 389 int phnum; 390 caddr_t entry; 391 392 dbg("processing main program's program header"); 393 assert(aux_info[AT_PHDR] != NULL); 394 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 395 assert(aux_info[AT_PHNUM] != NULL); 396 phnum = aux_info[AT_PHNUM]->a_un.a_val; 397 assert(aux_info[AT_PHENT] != NULL); 398 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 399 assert(aux_info[AT_ENTRY] != NULL); 400 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 401 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 402 die(); 403 } 404 405 if (aux_info[AT_EXECPATH] != 0) { 406 char *kexecpath; 407 char buf[MAXPATHLEN]; 408 409 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 410 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 411 if (kexecpath[0] == '/') 412 obj_main->path = kexecpath; 413 else if (getcwd(buf, sizeof(buf)) == NULL || 414 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 415 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 416 obj_main->path = xstrdup(argv0); 417 else 418 obj_main->path = xstrdup(buf); 419 } else { 420 dbg("No AT_EXECPATH"); 421 obj_main->path = xstrdup(argv0); 422 } 423 dbg("obj_main path %s", obj_main->path); 424 obj_main->mainprog = true; 425 426 /* 427 * Get the actual dynamic linker pathname from the executable if 428 * possible. (It should always be possible.) That ensures that 429 * gdb will find the right dynamic linker even if a non-standard 430 * one is being used. 431 */ 432 if (obj_main->interp != NULL && 433 strcmp(obj_main->interp, obj_rtld.path) != 0) { 434 free(obj_rtld.path); 435 obj_rtld.path = xstrdup(obj_main->interp); 436 __progname = obj_rtld.path; 437 } 438 439 digest_dynamic(obj_main, 0); 440 441 linkmap_add(obj_main); 442 linkmap_add(&obj_rtld); 443 444 /* Link the main program into the list of objects. */ 445 *obj_tail = obj_main; 446 obj_tail = &obj_main->next; 447 obj_count++; 448 obj_loads++; 449 /* Make sure we don't call the main program's init and fini functions. */ 450 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 451 452 /* Initialize a fake symbol for resolving undefined weak references. */ 453 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 454 sym_zero.st_shndx = SHN_UNDEF; 455 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 456 457 if (!libmap_disable) 458 libmap_disable = (bool)lm_init(libmap_override); 459 460 dbg("loading LD_PRELOAD libraries"); 461 if (load_preload_objects() == -1) 462 die(); 463 preload_tail = obj_tail; 464 465 dbg("loading needed objects"); 466 if (load_needed_objects(obj_main, 0) == -1) 467 die(); 468 469 /* Make a list of all objects loaded at startup. */ 470 for (obj = obj_list; obj != NULL; obj = obj->next) { 471 objlist_push_tail(&list_main, obj); 472 obj->refcount++; 473 } 474 475 dbg("checking for required versions"); 476 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 477 die(); 478 479 if (ld_tracing) { /* We're done */ 480 trace_loaded_objects(obj_main); 481 exit(0); 482 } 483 484 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 485 dump_relocations(obj_main); 486 exit (0); 487 } 488 489 /* setup TLS for main thread */ 490 dbg("initializing initial thread local storage"); 491 STAILQ_FOREACH(entry, &list_main, link) { 492 /* 493 * Allocate all the initial objects out of the static TLS 494 * block even if they didn't ask for it. 495 */ 496 allocate_tls_offset(entry->obj); 497 } 498 allocate_initial_tls(obj_list); 499 500 if (relocate_objects(obj_main, 501 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 502 die(); 503 504 dbg("doing copy relocations"); 505 if (do_copy_relocations(obj_main) == -1) 506 die(); 507 508 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 509 dump_relocations(obj_main); 510 exit (0); 511 } 512 513 dbg("initializing key program variables"); 514 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 515 set_program_var("environ", env); 516 set_program_var("__elf_aux_vector", aux); 517 518 dbg("initializing thread locks"); 519 lockdflt_init(); 520 521 /* Make a list of init functions to call. */ 522 objlist_init(&initlist); 523 initlist_add_objects(obj_list, preload_tail, &initlist); 524 525 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 526 527 lockstate = wlock_acquire(rtld_bind_lock); 528 objlist_call_init(&initlist, &lockstate); 529 objlist_clear(&initlist); 530 wlock_release(rtld_bind_lock, lockstate); 531 532 dbg("transferring control to program entry point = %p", obj_main->entry); 533 534 /* Return the exit procedure and the program entry point. */ 535 *exit_proc = rtld_exit; 536 *objp = obj_main; 537 return (func_ptr_type) obj_main->entry; 538 } 539 540 Elf_Addr 541 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 542 { 543 const Elf_Rel *rel; 544 const Elf_Sym *def; 545 const Obj_Entry *defobj; 546 Elf_Addr *where; 547 Elf_Addr target; 548 int lockstate; 549 550 lockstate = rlock_acquire(rtld_bind_lock); 551 if (obj->pltrel) 552 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 553 else 554 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 555 556 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 557 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 558 if (def == NULL) 559 die(); 560 561 target = (Elf_Addr)(defobj->relocbase + def->st_value); 562 563 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 564 defobj->strtab + def->st_name, basename(obj->path), 565 (void *)target, basename(defobj->path)); 566 567 /* 568 * Write the new contents for the jmpslot. Note that depending on 569 * architecture, the value which we need to return back to the 570 * lazy binding trampoline may or may not be the target 571 * address. The value returned from reloc_jmpslot() is the value 572 * that the trampoline needs. 573 */ 574 target = reloc_jmpslot(where, target, defobj, obj, rel); 575 rlock_release(rtld_bind_lock, lockstate); 576 return target; 577 } 578 579 /* 580 * Error reporting function. Use it like printf. If formats the message 581 * into a buffer, and sets things up so that the next call to dlerror() 582 * will return the message. 583 */ 584 void 585 _rtld_error(const char *fmt, ...) 586 { 587 static char buf[512]; 588 va_list ap; 589 590 va_start(ap, fmt); 591 vsnprintf(buf, sizeof buf, fmt, ap); 592 error_message = buf; 593 va_end(ap); 594 } 595 596 /* 597 * Return a dynamically-allocated copy of the current error message, if any. 598 */ 599 static char * 600 errmsg_save(void) 601 { 602 return error_message == NULL ? NULL : xstrdup(error_message); 603 } 604 605 /* 606 * Restore the current error message from a copy which was previously saved 607 * by errmsg_save(). The copy is freed. 608 */ 609 static void 610 errmsg_restore(char *saved_msg) 611 { 612 if (saved_msg == NULL) 613 error_message = NULL; 614 else { 615 _rtld_error("%s", saved_msg); 616 free(saved_msg); 617 } 618 } 619 620 static const char * 621 basename(const char *name) 622 { 623 const char *p = strrchr(name, '/'); 624 return p != NULL ? p + 1 : name; 625 } 626 627 static struct utsname uts; 628 629 static int 630 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 631 char *may_free) 632 { 633 const char *p, *p1; 634 char *res1; 635 int subst_len; 636 int kw_len; 637 638 res1 = *res = NULL; 639 p = real; 640 subst_len = kw_len = 0; 641 for (;;) { 642 p1 = strstr(p, kw); 643 if (p1 != NULL) { 644 if (subst_len == 0) { 645 subst_len = strlen(subst); 646 kw_len = strlen(kw); 647 } 648 if (*res == NULL) { 649 *res = xmalloc(PATH_MAX); 650 res1 = *res; 651 } 652 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 653 _rtld_error("Substitution of %s in %s cannot be performed", 654 kw, real); 655 if (may_free != NULL) 656 free(may_free); 657 free(res); 658 return (false); 659 } 660 memcpy(res1, p, p1 - p); 661 res1 += p1 - p; 662 memcpy(res1, subst, subst_len); 663 res1 += subst_len; 664 p = p1 + kw_len; 665 } else { 666 if (*res == NULL) { 667 if (may_free != NULL) 668 *res = may_free; 669 else 670 *res = xstrdup(real); 671 return (true); 672 } 673 *res1 = '\0'; 674 if (may_free != NULL) 675 free(may_free); 676 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 677 free(res); 678 return (false); 679 } 680 return (true); 681 } 682 } 683 } 684 685 static char * 686 origin_subst(const char *real, const char *origin_path) 687 { 688 char *res1, *res2, *res3, *res4; 689 690 if (uts.sysname[0] == '\0') { 691 if (uname(&uts) != 0) { 692 _rtld_error("utsname failed: %d", errno); 693 return (NULL); 694 } 695 } 696 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 697 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 698 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 699 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 700 return (NULL); 701 return (res4); 702 } 703 704 static void 705 die(void) 706 { 707 const char *msg = dlerror(); 708 709 if (msg == NULL) 710 msg = "Fatal error"; 711 errx(1, "%s", msg); 712 } 713 714 /* 715 * Process a shared object's DYNAMIC section, and save the important 716 * information in its Obj_Entry structure. 717 */ 718 static void 719 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 720 const Elf_Dyn **dyn_soname) 721 { 722 const Elf_Dyn *dynp; 723 Needed_Entry **needed_tail = &obj->needed; 724 int plttype = DT_REL; 725 726 *dyn_rpath = NULL; 727 *dyn_soname = NULL; 728 729 obj->bind_now = false; 730 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 731 switch (dynp->d_tag) { 732 733 case DT_REL: 734 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 735 break; 736 737 case DT_RELSZ: 738 obj->relsize = dynp->d_un.d_val; 739 break; 740 741 case DT_RELENT: 742 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 743 break; 744 745 case DT_JMPREL: 746 obj->pltrel = (const Elf_Rel *) 747 (obj->relocbase + dynp->d_un.d_ptr); 748 break; 749 750 case DT_PLTRELSZ: 751 obj->pltrelsize = dynp->d_un.d_val; 752 break; 753 754 case DT_RELA: 755 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 756 break; 757 758 case DT_RELASZ: 759 obj->relasize = dynp->d_un.d_val; 760 break; 761 762 case DT_RELAENT: 763 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 764 break; 765 766 case DT_PLTREL: 767 plttype = dynp->d_un.d_val; 768 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 769 break; 770 771 case DT_SYMTAB: 772 obj->symtab = (const Elf_Sym *) 773 (obj->relocbase + dynp->d_un.d_ptr); 774 break; 775 776 case DT_SYMENT: 777 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 778 break; 779 780 case DT_STRTAB: 781 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 782 break; 783 784 case DT_STRSZ: 785 obj->strsize = dynp->d_un.d_val; 786 break; 787 788 case DT_VERNEED: 789 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 790 dynp->d_un.d_val); 791 break; 792 793 case DT_VERNEEDNUM: 794 obj->verneednum = dynp->d_un.d_val; 795 break; 796 797 case DT_VERDEF: 798 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 799 dynp->d_un.d_val); 800 break; 801 802 case DT_VERDEFNUM: 803 obj->verdefnum = dynp->d_un.d_val; 804 break; 805 806 case DT_VERSYM: 807 obj->versyms = (const Elf_Versym *)(obj->relocbase + 808 dynp->d_un.d_val); 809 break; 810 811 case DT_HASH: 812 { 813 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 814 (obj->relocbase + dynp->d_un.d_ptr); 815 obj->nbuckets = hashtab[0]; 816 obj->nchains = hashtab[1]; 817 obj->buckets = hashtab + 2; 818 obj->chains = obj->buckets + obj->nbuckets; 819 } 820 break; 821 822 case DT_NEEDED: 823 if (!obj->rtld) { 824 Needed_Entry *nep = NEW(Needed_Entry); 825 nep->name = dynp->d_un.d_val; 826 nep->obj = NULL; 827 nep->next = NULL; 828 829 *needed_tail = nep; 830 needed_tail = &nep->next; 831 } 832 break; 833 834 case DT_PLTGOT: 835 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 836 break; 837 838 case DT_TEXTREL: 839 obj->textrel = true; 840 break; 841 842 case DT_SYMBOLIC: 843 obj->symbolic = true; 844 break; 845 846 case DT_RPATH: 847 case DT_RUNPATH: /* XXX: process separately */ 848 /* 849 * We have to wait until later to process this, because we 850 * might not have gotten the address of the string table yet. 851 */ 852 *dyn_rpath = dynp; 853 break; 854 855 case DT_SONAME: 856 *dyn_soname = dynp; 857 break; 858 859 case DT_INIT: 860 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 861 break; 862 863 case DT_FINI: 864 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 865 break; 866 867 /* 868 * Don't process DT_DEBUG on MIPS as the dynamic section 869 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 870 */ 871 872 #ifndef __mips__ 873 case DT_DEBUG: 874 /* XXX - not implemented yet */ 875 if (!early) 876 dbg("Filling in DT_DEBUG entry"); 877 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 878 break; 879 #endif 880 881 case DT_FLAGS: 882 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 883 obj->z_origin = true; 884 if (dynp->d_un.d_val & DF_SYMBOLIC) 885 obj->symbolic = true; 886 if (dynp->d_un.d_val & DF_TEXTREL) 887 obj->textrel = true; 888 if (dynp->d_un.d_val & DF_BIND_NOW) 889 obj->bind_now = true; 890 if (dynp->d_un.d_val & DF_STATIC_TLS) 891 ; 892 break; 893 #ifdef __mips__ 894 case DT_MIPS_LOCAL_GOTNO: 895 obj->local_gotno = dynp->d_un.d_val; 896 break; 897 898 case DT_MIPS_SYMTABNO: 899 obj->symtabno = dynp->d_un.d_val; 900 break; 901 902 case DT_MIPS_GOTSYM: 903 obj->gotsym = dynp->d_un.d_val; 904 break; 905 906 case DT_MIPS_RLD_MAP: 907 #ifdef notyet 908 if (!early) 909 dbg("Filling in DT_DEBUG entry"); 910 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 911 #endif 912 break; 913 #endif 914 915 case DT_FLAGS_1: 916 if (dynp->d_un.d_val & DF_1_NOOPEN) 917 obj->z_noopen = true; 918 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 919 obj->z_origin = true; 920 if (dynp->d_un.d_val & DF_1_GLOBAL) 921 /* XXX */; 922 if (dynp->d_un.d_val & DF_1_BIND_NOW) 923 obj->bind_now = true; 924 if (dynp->d_un.d_val & DF_1_NODELETE) 925 obj->z_nodelete = true; 926 break; 927 928 default: 929 if (!early) { 930 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 931 (long)dynp->d_tag); 932 } 933 break; 934 } 935 } 936 937 obj->traced = false; 938 939 if (plttype == DT_RELA) { 940 obj->pltrela = (const Elf_Rela *) obj->pltrel; 941 obj->pltrel = NULL; 942 obj->pltrelasize = obj->pltrelsize; 943 obj->pltrelsize = 0; 944 } 945 } 946 947 static void 948 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 949 const Elf_Dyn *dyn_soname) 950 { 951 952 if (obj->z_origin && obj->origin_path == NULL) { 953 obj->origin_path = xmalloc(PATH_MAX); 954 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 955 die(); 956 } 957 958 if (dyn_rpath != NULL) { 959 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 960 if (obj->z_origin) 961 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 962 } 963 964 if (dyn_soname != NULL) 965 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 966 } 967 968 static void 969 digest_dynamic(Obj_Entry *obj, int early) 970 { 971 const Elf_Dyn *dyn_rpath; 972 const Elf_Dyn *dyn_soname; 973 974 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 975 digest_dynamic2(obj, dyn_rpath, dyn_soname); 976 } 977 978 /* 979 * Process a shared object's program header. This is used only for the 980 * main program, when the kernel has already loaded the main program 981 * into memory before calling the dynamic linker. It creates and 982 * returns an Obj_Entry structure. 983 */ 984 static Obj_Entry * 985 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 986 { 987 Obj_Entry *obj; 988 const Elf_Phdr *phlimit = phdr + phnum; 989 const Elf_Phdr *ph; 990 int nsegs = 0; 991 992 obj = obj_new(); 993 for (ph = phdr; ph < phlimit; ph++) { 994 if (ph->p_type != PT_PHDR) 995 continue; 996 997 obj->phdr = phdr; 998 obj->phsize = ph->p_memsz; 999 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1000 break; 1001 } 1002 1003 for (ph = phdr; ph < phlimit; ph++) { 1004 switch (ph->p_type) { 1005 1006 case PT_INTERP: 1007 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1008 break; 1009 1010 case PT_LOAD: 1011 if (nsegs == 0) { /* First load segment */ 1012 obj->vaddrbase = trunc_page(ph->p_vaddr); 1013 obj->mapbase = obj->vaddrbase + obj->relocbase; 1014 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1015 obj->vaddrbase; 1016 } else { /* Last load segment */ 1017 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1018 obj->vaddrbase; 1019 } 1020 nsegs++; 1021 break; 1022 1023 case PT_DYNAMIC: 1024 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1025 break; 1026 1027 case PT_TLS: 1028 obj->tlsindex = 1; 1029 obj->tlssize = ph->p_memsz; 1030 obj->tlsalign = ph->p_align; 1031 obj->tlsinitsize = ph->p_filesz; 1032 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1033 break; 1034 } 1035 } 1036 if (nsegs < 1) { 1037 _rtld_error("%s: too few PT_LOAD segments", path); 1038 return NULL; 1039 } 1040 1041 obj->entry = entry; 1042 return obj; 1043 } 1044 1045 static Obj_Entry * 1046 dlcheck(void *handle) 1047 { 1048 Obj_Entry *obj; 1049 1050 for (obj = obj_list; obj != NULL; obj = obj->next) 1051 if (obj == (Obj_Entry *) handle) 1052 break; 1053 1054 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1055 _rtld_error("Invalid shared object handle %p", handle); 1056 return NULL; 1057 } 1058 return obj; 1059 } 1060 1061 /* 1062 * If the given object is already in the donelist, return true. Otherwise 1063 * add the object to the list and return false. 1064 */ 1065 static bool 1066 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1067 { 1068 unsigned int i; 1069 1070 for (i = 0; i < dlp->num_used; i++) 1071 if (dlp->objs[i] == obj) 1072 return true; 1073 /* 1074 * Our donelist allocation should always be sufficient. But if 1075 * our threads locking isn't working properly, more shared objects 1076 * could have been loaded since we allocated the list. That should 1077 * never happen, but we'll handle it properly just in case it does. 1078 */ 1079 if (dlp->num_used < dlp->num_alloc) 1080 dlp->objs[dlp->num_used++] = obj; 1081 return false; 1082 } 1083 1084 /* 1085 * Hash function for symbol table lookup. Don't even think about changing 1086 * this. It is specified by the System V ABI. 1087 */ 1088 unsigned long 1089 elf_hash(const char *name) 1090 { 1091 const unsigned char *p = (const unsigned char *) name; 1092 unsigned long h = 0; 1093 unsigned long g; 1094 1095 while (*p != '\0') { 1096 h = (h << 4) + *p++; 1097 if ((g = h & 0xf0000000) != 0) 1098 h ^= g >> 24; 1099 h &= ~g; 1100 } 1101 return h; 1102 } 1103 1104 /* 1105 * Find the library with the given name, and return its full pathname. 1106 * The returned string is dynamically allocated. Generates an error 1107 * message and returns NULL if the library cannot be found. 1108 * 1109 * If the second argument is non-NULL, then it refers to an already- 1110 * loaded shared object, whose library search path will be searched. 1111 * 1112 * The search order is: 1113 * LD_LIBRARY_PATH 1114 * rpath in the referencing file 1115 * ldconfig hints 1116 * /lib:/usr/lib 1117 */ 1118 static char * 1119 find_library(const char *xname, const Obj_Entry *refobj) 1120 { 1121 char *pathname; 1122 char *name; 1123 1124 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1125 if (xname[0] != '/' && !trust) { 1126 _rtld_error("Absolute pathname required for shared object \"%s\"", 1127 xname); 1128 return NULL; 1129 } 1130 if (refobj != NULL && refobj->z_origin) 1131 return origin_subst(xname, refobj->origin_path); 1132 else 1133 return xstrdup(xname); 1134 } 1135 1136 if (libmap_disable || (refobj == NULL) || 1137 (name = lm_find(refobj->path, xname)) == NULL) 1138 name = (char *)xname; 1139 1140 dbg(" Searching for \"%s\"", name); 1141 1142 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1143 (refobj != NULL && 1144 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1145 (pathname = search_library_path(name, gethints())) != NULL || 1146 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1147 return pathname; 1148 1149 if(refobj != NULL && refobj->path != NULL) { 1150 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1151 name, basename(refobj->path)); 1152 } else { 1153 _rtld_error("Shared object \"%s\" not found", name); 1154 } 1155 return NULL; 1156 } 1157 1158 /* 1159 * Given a symbol number in a referencing object, find the corresponding 1160 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1161 * no definition was found. Returns a pointer to the Obj_Entry of the 1162 * defining object via the reference parameter DEFOBJ_OUT. 1163 */ 1164 const Elf_Sym * 1165 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1166 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1167 { 1168 const Elf_Sym *ref; 1169 const Elf_Sym *def; 1170 const Obj_Entry *defobj; 1171 const Ver_Entry *ventry; 1172 const char *name; 1173 unsigned long hash; 1174 1175 /* 1176 * If we have already found this symbol, get the information from 1177 * the cache. 1178 */ 1179 if (symnum >= refobj->nchains) 1180 return NULL; /* Bad object */ 1181 if (cache != NULL && cache[symnum].sym != NULL) { 1182 *defobj_out = cache[symnum].obj; 1183 return cache[symnum].sym; 1184 } 1185 1186 ref = refobj->symtab + symnum; 1187 name = refobj->strtab + ref->st_name; 1188 defobj = NULL; 1189 1190 /* 1191 * We don't have to do a full scale lookup if the symbol is local. 1192 * We know it will bind to the instance in this load module; to 1193 * which we already have a pointer (ie ref). By not doing a lookup, 1194 * we not only improve performance, but it also avoids unresolvable 1195 * symbols when local symbols are not in the hash table. This has 1196 * been seen with the ia64 toolchain. 1197 */ 1198 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1199 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1200 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1201 symnum); 1202 } 1203 ventry = fetch_ventry(refobj, symnum); 1204 hash = elf_hash(name); 1205 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1206 } else { 1207 def = ref; 1208 defobj = refobj; 1209 } 1210 1211 /* 1212 * If we found no definition and the reference is weak, treat the 1213 * symbol as having the value zero. 1214 */ 1215 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1216 def = &sym_zero; 1217 defobj = obj_main; 1218 } 1219 1220 if (def != NULL) { 1221 *defobj_out = defobj; 1222 /* Record the information in the cache to avoid subsequent lookups. */ 1223 if (cache != NULL) { 1224 cache[symnum].sym = def; 1225 cache[symnum].obj = defobj; 1226 } 1227 } else { 1228 if (refobj != &obj_rtld) 1229 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1230 } 1231 return def; 1232 } 1233 1234 /* 1235 * Return the search path from the ldconfig hints file, reading it if 1236 * necessary. Returns NULL if there are problems with the hints file, 1237 * or if the search path there is empty. 1238 */ 1239 static const char * 1240 gethints(void) 1241 { 1242 static char *hints; 1243 1244 if (hints == NULL) { 1245 int fd; 1246 struct elfhints_hdr hdr; 1247 char *p; 1248 1249 /* Keep from trying again in case the hints file is bad. */ 1250 hints = ""; 1251 1252 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1253 return NULL; 1254 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1255 hdr.magic != ELFHINTS_MAGIC || 1256 hdr.version != 1) { 1257 close(fd); 1258 return NULL; 1259 } 1260 p = xmalloc(hdr.dirlistlen + 1); 1261 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1262 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1263 free(p); 1264 close(fd); 1265 return NULL; 1266 } 1267 hints = p; 1268 close(fd); 1269 } 1270 return hints[0] != '\0' ? hints : NULL; 1271 } 1272 1273 static void 1274 init_dag(Obj_Entry *root) 1275 { 1276 DoneList donelist; 1277 1278 if (root->dag_inited) 1279 return; 1280 donelist_init(&donelist); 1281 init_dag1(root, root, &donelist); 1282 root->dag_inited = true; 1283 } 1284 1285 static void 1286 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1287 { 1288 const Needed_Entry *needed; 1289 1290 if (donelist_check(dlp, obj)) 1291 return; 1292 1293 obj->refcount++; 1294 objlist_push_tail(&obj->dldags, root); 1295 objlist_push_tail(&root->dagmembers, obj); 1296 for (needed = obj->needed; needed != NULL; needed = needed->next) 1297 if (needed->obj != NULL) 1298 init_dag1(root, needed->obj, dlp); 1299 } 1300 1301 /* 1302 * Initialize the dynamic linker. The argument is the address at which 1303 * the dynamic linker has been mapped into memory. The primary task of 1304 * this function is to relocate the dynamic linker. 1305 */ 1306 static void 1307 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1308 { 1309 Obj_Entry objtmp; /* Temporary rtld object */ 1310 const Elf_Dyn *dyn_rpath; 1311 const Elf_Dyn *dyn_soname; 1312 1313 /* 1314 * Conjure up an Obj_Entry structure for the dynamic linker. 1315 * 1316 * The "path" member can't be initialized yet because string constants 1317 * cannot yet be accessed. Below we will set it correctly. 1318 */ 1319 memset(&objtmp, 0, sizeof(objtmp)); 1320 objtmp.path = NULL; 1321 objtmp.rtld = true; 1322 objtmp.mapbase = mapbase; 1323 #ifdef PIC 1324 objtmp.relocbase = mapbase; 1325 #endif 1326 if (RTLD_IS_DYNAMIC()) { 1327 objtmp.dynamic = rtld_dynamic(&objtmp); 1328 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1329 assert(objtmp.needed == NULL); 1330 #if !defined(__mips__) 1331 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1332 assert(!objtmp.textrel); 1333 #endif 1334 1335 /* 1336 * Temporarily put the dynamic linker entry into the object list, so 1337 * that symbols can be found. 1338 */ 1339 1340 relocate_objects(&objtmp, true, &objtmp); 1341 } 1342 1343 /* Initialize the object list. */ 1344 obj_tail = &obj_list; 1345 1346 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1347 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1348 1349 if (aux_info[AT_PAGESZ] != NULL) 1350 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1351 if (aux_info[AT_OSRELDATE] != NULL) 1352 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1353 1354 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1355 1356 /* Replace the path with a dynamically allocated copy. */ 1357 obj_rtld.path = xstrdup(PATH_RTLD); 1358 1359 r_debug.r_brk = r_debug_state; 1360 r_debug.r_state = RT_CONSISTENT; 1361 } 1362 1363 /* 1364 * Add the init functions from a needed object list (and its recursive 1365 * needed objects) to "list". This is not used directly; it is a helper 1366 * function for initlist_add_objects(). The write lock must be held 1367 * when this function is called. 1368 */ 1369 static void 1370 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1371 { 1372 /* Recursively process the successor needed objects. */ 1373 if (needed->next != NULL) 1374 initlist_add_neededs(needed->next, list); 1375 1376 /* Process the current needed object. */ 1377 if (needed->obj != NULL) 1378 initlist_add_objects(needed->obj, &needed->obj->next, list); 1379 } 1380 1381 /* 1382 * Scan all of the DAGs rooted in the range of objects from "obj" to 1383 * "tail" and add their init functions to "list". This recurses over 1384 * the DAGs and ensure the proper init ordering such that each object's 1385 * needed libraries are initialized before the object itself. At the 1386 * same time, this function adds the objects to the global finalization 1387 * list "list_fini" in the opposite order. The write lock must be 1388 * held when this function is called. 1389 */ 1390 static void 1391 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1392 { 1393 if (obj->init_scanned || obj->init_done) 1394 return; 1395 obj->init_scanned = true; 1396 1397 /* Recursively process the successor objects. */ 1398 if (&obj->next != tail) 1399 initlist_add_objects(obj->next, tail, list); 1400 1401 /* Recursively process the needed objects. */ 1402 if (obj->needed != NULL) 1403 initlist_add_neededs(obj->needed, list); 1404 1405 /* Add the object to the init list. */ 1406 if (obj->init != (Elf_Addr)NULL) 1407 objlist_push_tail(list, obj); 1408 1409 /* Add the object to the global fini list in the reverse order. */ 1410 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1411 objlist_push_head(&list_fini, obj); 1412 obj->on_fini_list = true; 1413 } 1414 } 1415 1416 #ifndef FPTR_TARGET 1417 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1418 #endif 1419 1420 /* 1421 * Given a shared object, traverse its list of needed objects, and load 1422 * each of them. Returns 0 on success. Generates an error message and 1423 * returns -1 on failure. 1424 */ 1425 static int 1426 load_needed_objects(Obj_Entry *first, int flags) 1427 { 1428 Obj_Entry *obj, *obj1; 1429 1430 for (obj = first; obj != NULL; obj = obj->next) { 1431 Needed_Entry *needed; 1432 1433 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1434 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1435 flags & ~RTLD_LO_NOLOAD); 1436 if (obj1 == NULL && !ld_tracing) 1437 return -1; 1438 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1439 dbg("obj %s nodelete", obj1->path); 1440 init_dag(obj1); 1441 ref_dag(obj1); 1442 obj1->ref_nodel = true; 1443 } 1444 } 1445 } 1446 1447 return 0; 1448 } 1449 1450 static int 1451 load_preload_objects(void) 1452 { 1453 char *p = ld_preload; 1454 static const char delim[] = " \t:;"; 1455 1456 if (p == NULL) 1457 return 0; 1458 1459 p += strspn(p, delim); 1460 while (*p != '\0') { 1461 size_t len = strcspn(p, delim); 1462 char savech; 1463 1464 savech = p[len]; 1465 p[len] = '\0'; 1466 if (load_object(p, NULL, 0) == NULL) 1467 return -1; /* XXX - cleanup */ 1468 p[len] = savech; 1469 p += len; 1470 p += strspn(p, delim); 1471 } 1472 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1473 return 0; 1474 } 1475 1476 /* 1477 * Load a shared object into memory, if it is not already loaded. 1478 * 1479 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1480 * on failure. 1481 */ 1482 static Obj_Entry * 1483 load_object(const char *name, const Obj_Entry *refobj, int flags) 1484 { 1485 Obj_Entry *obj; 1486 int fd = -1; 1487 struct stat sb; 1488 char *path; 1489 1490 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1491 if (object_match_name(obj, name)) 1492 return obj; 1493 1494 path = find_library(name, refobj); 1495 if (path == NULL) 1496 return NULL; 1497 1498 /* 1499 * If we didn't find a match by pathname, open the file and check 1500 * again by device and inode. This avoids false mismatches caused 1501 * by multiple links or ".." in pathnames. 1502 * 1503 * To avoid a race, we open the file and use fstat() rather than 1504 * using stat(). 1505 */ 1506 if ((fd = open(path, O_RDONLY)) == -1) { 1507 _rtld_error("Cannot open \"%s\"", path); 1508 free(path); 1509 return NULL; 1510 } 1511 if (fstat(fd, &sb) == -1) { 1512 _rtld_error("Cannot fstat \"%s\"", path); 1513 close(fd); 1514 free(path); 1515 return NULL; 1516 } 1517 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1518 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1519 close(fd); 1520 break; 1521 } 1522 } 1523 if (obj != NULL) { 1524 object_add_name(obj, name); 1525 free(path); 1526 close(fd); 1527 return obj; 1528 } 1529 if (flags & RTLD_LO_NOLOAD) { 1530 free(path); 1531 return (NULL); 1532 } 1533 1534 /* First use of this object, so we must map it in */ 1535 obj = do_load_object(fd, name, path, &sb, flags); 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 int flags) 1546 { 1547 Obj_Entry *obj; 1548 struct statfs fs; 1549 1550 /* 1551 * but first, make sure that environment variables haven't been 1552 * used to circumvent the noexec flag on a filesystem. 1553 */ 1554 if (dangerous_ld_env) { 1555 if (fstatfs(fd, &fs) != 0) { 1556 _rtld_error("Cannot fstatfs \"%s\"", path); 1557 return NULL; 1558 } 1559 if (fs.f_flags & MNT_NOEXEC) { 1560 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1561 return NULL; 1562 } 1563 } 1564 dbg("loading \"%s\"", path); 1565 obj = map_object(fd, path, sbp); 1566 if (obj == NULL) 1567 return NULL; 1568 1569 object_add_name(obj, name); 1570 obj->path = path; 1571 digest_dynamic(obj, 0); 1572 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1573 RTLD_LO_DLOPEN) { 1574 dbg("refusing to load non-loadable \"%s\"", obj->path); 1575 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1576 munmap(obj->mapbase, obj->mapsize); 1577 obj_free(obj); 1578 return (NULL); 1579 } 1580 1581 *obj_tail = obj; 1582 obj_tail = &obj->next; 1583 obj_count++; 1584 obj_loads++; 1585 linkmap_add(obj); /* for GDB & dlinfo() */ 1586 1587 dbg(" %p .. %p: %s", obj->mapbase, 1588 obj->mapbase + obj->mapsize - 1, obj->path); 1589 if (obj->textrel) 1590 dbg(" WARNING: %s has impure text", obj->path); 1591 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1592 obj->path); 1593 1594 return obj; 1595 } 1596 1597 static Obj_Entry * 1598 obj_from_addr(const void *addr) 1599 { 1600 Obj_Entry *obj; 1601 1602 for (obj = obj_list; obj != NULL; obj = obj->next) { 1603 if (addr < (void *) obj->mapbase) 1604 continue; 1605 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1606 return obj; 1607 } 1608 return NULL; 1609 } 1610 1611 /* 1612 * Call the finalization functions for each of the objects in "list" 1613 * which are unreferenced. All of the objects are expected to have 1614 * non-NULL fini functions. 1615 */ 1616 static void 1617 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1618 { 1619 Objlist_Entry *elm, *elm_tmp; 1620 char *saved_msg; 1621 1622 /* 1623 * Preserve the current error message since a fini function might 1624 * call into the dynamic linker and overwrite it. 1625 */ 1626 saved_msg = errmsg_save(); 1627 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1628 if (elm->obj->refcount == 0 || force) { 1629 dbg("calling fini function for %s at %p", elm->obj->path, 1630 (void *)elm->obj->fini); 1631 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1632 elm->obj->path); 1633 /* Remove object from fini list to prevent recursive invocation. */ 1634 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1635 wlock_release(rtld_bind_lock, *lockstate); 1636 call_initfini_pointer(elm->obj, elm->obj->fini); 1637 *lockstate = wlock_acquire(rtld_bind_lock); 1638 /* No need to free anything if process is going down. */ 1639 if (!force) 1640 free(elm); 1641 } 1642 } 1643 errmsg_restore(saved_msg); 1644 } 1645 1646 /* 1647 * Call the initialization functions for each of the objects in 1648 * "list". All of the objects are expected to have non-NULL init 1649 * functions. 1650 */ 1651 static void 1652 objlist_call_init(Objlist *list, int *lockstate) 1653 { 1654 Objlist_Entry *elm; 1655 Obj_Entry *obj; 1656 char *saved_msg; 1657 1658 /* 1659 * Clean init_scanned flag so that objects can be rechecked and 1660 * possibly initialized earlier if any of vectors called below 1661 * cause the change by using dlopen. 1662 */ 1663 for (obj = obj_list; obj != NULL; obj = obj->next) 1664 obj->init_scanned = false; 1665 1666 /* 1667 * Preserve the current error message since an init function might 1668 * call into the dynamic linker and overwrite it. 1669 */ 1670 saved_msg = errmsg_save(); 1671 STAILQ_FOREACH(elm, list, link) { 1672 if (elm->obj->init_done) /* Initialized early. */ 1673 continue; 1674 dbg("calling init function for %s at %p", elm->obj->path, 1675 (void *)elm->obj->init); 1676 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1677 elm->obj->path); 1678 /* 1679 * Race: other thread might try to use this object before current 1680 * one completes the initilization. Not much can be done here 1681 * without better locking. 1682 */ 1683 elm->obj->init_done = true; 1684 wlock_release(rtld_bind_lock, *lockstate); 1685 call_initfini_pointer(elm->obj, elm->obj->init); 1686 *lockstate = wlock_acquire(rtld_bind_lock); 1687 } 1688 errmsg_restore(saved_msg); 1689 } 1690 1691 static void 1692 objlist_clear(Objlist *list) 1693 { 1694 Objlist_Entry *elm; 1695 1696 while (!STAILQ_EMPTY(list)) { 1697 elm = STAILQ_FIRST(list); 1698 STAILQ_REMOVE_HEAD(list, link); 1699 free(elm); 1700 } 1701 } 1702 1703 static Objlist_Entry * 1704 objlist_find(Objlist *list, const Obj_Entry *obj) 1705 { 1706 Objlist_Entry *elm; 1707 1708 STAILQ_FOREACH(elm, list, link) 1709 if (elm->obj == obj) 1710 return elm; 1711 return NULL; 1712 } 1713 1714 static void 1715 objlist_init(Objlist *list) 1716 { 1717 STAILQ_INIT(list); 1718 } 1719 1720 static void 1721 objlist_push_head(Objlist *list, Obj_Entry *obj) 1722 { 1723 Objlist_Entry *elm; 1724 1725 elm = NEW(Objlist_Entry); 1726 elm->obj = obj; 1727 STAILQ_INSERT_HEAD(list, elm, link); 1728 } 1729 1730 static void 1731 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1732 { 1733 Objlist_Entry *elm; 1734 1735 elm = NEW(Objlist_Entry); 1736 elm->obj = obj; 1737 STAILQ_INSERT_TAIL(list, elm, link); 1738 } 1739 1740 static void 1741 objlist_remove(Objlist *list, Obj_Entry *obj) 1742 { 1743 Objlist_Entry *elm; 1744 1745 if ((elm = objlist_find(list, obj)) != NULL) { 1746 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1747 free(elm); 1748 } 1749 } 1750 1751 /* 1752 * Relocate newly-loaded shared objects. The argument is a pointer to 1753 * the Obj_Entry for the first such object. All objects from the first 1754 * to the end of the list of objects are relocated. Returns 0 on success, 1755 * or -1 on failure. 1756 */ 1757 static int 1758 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1759 { 1760 Obj_Entry *obj; 1761 1762 for (obj = first; obj != NULL; obj = obj->next) { 1763 if (obj != rtldobj) 1764 dbg("relocating \"%s\"", obj->path); 1765 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1766 obj->symtab == NULL || obj->strtab == NULL) { 1767 _rtld_error("%s: Shared object has no run-time symbol table", 1768 obj->path); 1769 return -1; 1770 } 1771 1772 if (obj->textrel) { 1773 /* There are relocations to the write-protected text segment. */ 1774 if (mprotect(obj->mapbase, obj->textsize, 1775 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1776 _rtld_error("%s: Cannot write-enable text segment: %s", 1777 obj->path, strerror(errno)); 1778 return -1; 1779 } 1780 } 1781 1782 /* Process the non-PLT relocations. */ 1783 if (reloc_non_plt(obj, rtldobj)) 1784 return -1; 1785 1786 if (obj->textrel) { /* Re-protected the text segment. */ 1787 if (mprotect(obj->mapbase, obj->textsize, 1788 PROT_READ|PROT_EXEC) == -1) { 1789 _rtld_error("%s: Cannot write-protect text segment: %s", 1790 obj->path, strerror(errno)); 1791 return -1; 1792 } 1793 } 1794 1795 /* Process the PLT relocations. */ 1796 if (reloc_plt(obj) == -1) 1797 return -1; 1798 /* Relocate the jump slots if we are doing immediate binding. */ 1799 if (obj->bind_now || bind_now) 1800 if (reloc_jmpslots(obj) == -1) 1801 return -1; 1802 1803 1804 /* 1805 * Set up the magic number and version in the Obj_Entry. These 1806 * were checked in the crt1.o from the original ElfKit, so we 1807 * set them for backward compatibility. 1808 */ 1809 obj->magic = RTLD_MAGIC; 1810 obj->version = RTLD_VERSION; 1811 1812 /* Set the special PLT or GOT entries. */ 1813 init_pltgot(obj); 1814 } 1815 1816 return 0; 1817 } 1818 1819 /* 1820 * Cleanup procedure. It will be called (by the atexit mechanism) just 1821 * before the process exits. 1822 */ 1823 static void 1824 rtld_exit(void) 1825 { 1826 int lockstate; 1827 1828 lockstate = wlock_acquire(rtld_bind_lock); 1829 dbg("rtld_exit()"); 1830 objlist_call_fini(&list_fini, true, &lockstate); 1831 /* No need to remove the items from the list, since we are exiting. */ 1832 if (!libmap_disable) 1833 lm_fini(); 1834 wlock_release(rtld_bind_lock, lockstate); 1835 } 1836 1837 static void * 1838 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1839 { 1840 #ifdef COMPAT_32BIT 1841 const char *trans; 1842 #endif 1843 if (path == NULL) 1844 return (NULL); 1845 1846 path += strspn(path, ":;"); 1847 while (*path != '\0') { 1848 size_t len; 1849 char *res; 1850 1851 len = strcspn(path, ":;"); 1852 #ifdef COMPAT_32BIT 1853 trans = lm_findn(NULL, path, len); 1854 if (trans) 1855 res = callback(trans, strlen(trans), arg); 1856 else 1857 #endif 1858 res = callback(path, len, arg); 1859 1860 if (res != NULL) 1861 return (res); 1862 1863 path += len; 1864 path += strspn(path, ":;"); 1865 } 1866 1867 return (NULL); 1868 } 1869 1870 struct try_library_args { 1871 const char *name; 1872 size_t namelen; 1873 char *buffer; 1874 size_t buflen; 1875 }; 1876 1877 static void * 1878 try_library_path(const char *dir, size_t dirlen, void *param) 1879 { 1880 struct try_library_args *arg; 1881 1882 arg = param; 1883 if (*dir == '/' || trust) { 1884 char *pathname; 1885 1886 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1887 return (NULL); 1888 1889 pathname = arg->buffer; 1890 strncpy(pathname, dir, dirlen); 1891 pathname[dirlen] = '/'; 1892 strcpy(pathname + dirlen + 1, arg->name); 1893 1894 dbg(" Trying \"%s\"", pathname); 1895 if (access(pathname, F_OK) == 0) { /* We found it */ 1896 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1897 strcpy(pathname, arg->buffer); 1898 return (pathname); 1899 } 1900 } 1901 return (NULL); 1902 } 1903 1904 static char * 1905 search_library_path(const char *name, const char *path) 1906 { 1907 char *p; 1908 struct try_library_args arg; 1909 1910 if (path == NULL) 1911 return NULL; 1912 1913 arg.name = name; 1914 arg.namelen = strlen(name); 1915 arg.buffer = xmalloc(PATH_MAX); 1916 arg.buflen = PATH_MAX; 1917 1918 p = path_enumerate(path, try_library_path, &arg); 1919 1920 free(arg.buffer); 1921 1922 return (p); 1923 } 1924 1925 int 1926 dlclose(void *handle) 1927 { 1928 Obj_Entry *root; 1929 int lockstate; 1930 1931 lockstate = wlock_acquire(rtld_bind_lock); 1932 root = dlcheck(handle); 1933 if (root == NULL) { 1934 wlock_release(rtld_bind_lock, lockstate); 1935 return -1; 1936 } 1937 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1938 root->path); 1939 1940 /* Unreference the object and its dependencies. */ 1941 root->dl_refcount--; 1942 1943 unref_dag(root); 1944 1945 if (root->refcount == 0) { 1946 /* 1947 * The object is no longer referenced, so we must unload it. 1948 * First, call the fini functions. 1949 */ 1950 objlist_call_fini(&list_fini, false, &lockstate); 1951 1952 /* Finish cleaning up the newly-unreferenced objects. */ 1953 GDB_STATE(RT_DELETE,&root->linkmap); 1954 unload_object(root); 1955 GDB_STATE(RT_CONSISTENT,NULL); 1956 } 1957 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1958 wlock_release(rtld_bind_lock, lockstate); 1959 return 0; 1960 } 1961 1962 char * 1963 dlerror(void) 1964 { 1965 char *msg = error_message; 1966 error_message = NULL; 1967 return msg; 1968 } 1969 1970 /* 1971 * This function is deprecated and has no effect. 1972 */ 1973 void 1974 dllockinit(void *context, 1975 void *(*lock_create)(void *context), 1976 void (*rlock_acquire)(void *lock), 1977 void (*wlock_acquire)(void *lock), 1978 void (*lock_release)(void *lock), 1979 void (*lock_destroy)(void *lock), 1980 void (*context_destroy)(void *context)) 1981 { 1982 static void *cur_context; 1983 static void (*cur_context_destroy)(void *); 1984 1985 /* Just destroy the context from the previous call, if necessary. */ 1986 if (cur_context_destroy != NULL) 1987 cur_context_destroy(cur_context); 1988 cur_context = context; 1989 cur_context_destroy = context_destroy; 1990 } 1991 1992 void * 1993 dlopen(const char *name, int mode) 1994 { 1995 Obj_Entry **old_obj_tail; 1996 Obj_Entry *obj; 1997 Objlist initlist; 1998 int result, lockstate, nodelete, lo_flags; 1999 2000 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2001 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2002 if (ld_tracing != NULL) 2003 environ = (char **)*get_program_var_addr("environ"); 2004 nodelete = mode & RTLD_NODELETE; 2005 lo_flags = RTLD_LO_DLOPEN; 2006 if (mode & RTLD_NOLOAD) 2007 lo_flags |= RTLD_LO_NOLOAD; 2008 if (ld_tracing != NULL) 2009 lo_flags |= RTLD_LO_TRACE; 2010 2011 objlist_init(&initlist); 2012 2013 lockstate = wlock_acquire(rtld_bind_lock); 2014 GDB_STATE(RT_ADD,NULL); 2015 2016 old_obj_tail = obj_tail; 2017 obj = NULL; 2018 if (name == NULL) { 2019 obj = obj_main; 2020 obj->refcount++; 2021 } else { 2022 obj = load_object(name, obj_main, lo_flags); 2023 } 2024 2025 if (obj) { 2026 obj->dl_refcount++; 2027 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2028 objlist_push_tail(&list_global, obj); 2029 mode &= RTLD_MODEMASK; 2030 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2031 assert(*old_obj_tail == obj); 2032 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2033 init_dag(obj); 2034 if (result != -1) 2035 result = rtld_verify_versions(&obj->dagmembers); 2036 if (result != -1 && ld_tracing) 2037 goto trace; 2038 if (result == -1 || 2039 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2040 obj->dl_refcount--; 2041 unref_dag(obj); 2042 if (obj->refcount == 0) 2043 unload_object(obj); 2044 obj = NULL; 2045 } else { 2046 /* Make list of init functions to call. */ 2047 initlist_add_objects(obj, &obj->next, &initlist); 2048 } 2049 } else { 2050 2051 /* 2052 * Bump the reference counts for objects on this DAG. If 2053 * this is the first dlopen() call for the object that was 2054 * already loaded as a dependency, initialize the dag 2055 * starting at it. 2056 */ 2057 if (obj->dl_refcount == 1) 2058 init_dag(obj); 2059 else 2060 ref_dag(obj); 2061 2062 if (ld_tracing) 2063 goto trace; 2064 } 2065 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2066 dbg("obj %s nodelete", obj->path); 2067 ref_dag(obj); 2068 obj->z_nodelete = obj->ref_nodel = true; 2069 } 2070 } 2071 2072 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2073 name); 2074 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2075 2076 /* Call the init functions. */ 2077 objlist_call_init(&initlist, &lockstate); 2078 objlist_clear(&initlist); 2079 wlock_release(rtld_bind_lock, lockstate); 2080 return obj; 2081 trace: 2082 trace_loaded_objects(obj); 2083 wlock_release(rtld_bind_lock, lockstate); 2084 exit(0); 2085 } 2086 2087 static void * 2088 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2089 int flags) 2090 { 2091 DoneList donelist; 2092 const Obj_Entry *obj, *defobj; 2093 const Elf_Sym *def, *symp; 2094 unsigned long hash; 2095 int lockstate; 2096 2097 hash = elf_hash(name); 2098 def = NULL; 2099 defobj = NULL; 2100 flags |= SYMLOOK_IN_PLT; 2101 2102 lockstate = rlock_acquire(rtld_bind_lock); 2103 if (handle == NULL || handle == RTLD_NEXT || 2104 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2105 2106 if ((obj = obj_from_addr(retaddr)) == NULL) { 2107 _rtld_error("Cannot determine caller's shared object"); 2108 rlock_release(rtld_bind_lock, lockstate); 2109 return NULL; 2110 } 2111 if (handle == NULL) { /* Just the caller's shared object. */ 2112 def = symlook_obj(name, hash, obj, ve, flags); 2113 defobj = obj; 2114 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2115 handle == RTLD_SELF) { /* ... caller included */ 2116 if (handle == RTLD_NEXT) 2117 obj = obj->next; 2118 for (; obj != NULL; obj = obj->next) { 2119 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2120 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2121 def = symp; 2122 defobj = obj; 2123 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2124 break; 2125 } 2126 } 2127 } 2128 /* 2129 * Search the dynamic linker itself, and possibly resolve the 2130 * symbol from there. This is how the application links to 2131 * dynamic linker services such as dlopen. 2132 */ 2133 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2134 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2135 if (symp != NULL) { 2136 def = symp; 2137 defobj = &obj_rtld; 2138 } 2139 } 2140 } else { 2141 assert(handle == RTLD_DEFAULT); 2142 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2143 } 2144 } else { 2145 if ((obj = dlcheck(handle)) == NULL) { 2146 rlock_release(rtld_bind_lock, lockstate); 2147 return NULL; 2148 } 2149 2150 donelist_init(&donelist); 2151 if (obj->mainprog) { 2152 /* Search main program and all libraries loaded by it. */ 2153 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2154 &donelist); 2155 2156 /* 2157 * We do not distinguish between 'main' object and global scope. 2158 * If symbol is not defined by objects loaded at startup, continue 2159 * search among dynamically loaded objects with RTLD_GLOBAL 2160 * scope. 2161 */ 2162 if (def == NULL) 2163 def = symlook_list(name, hash, &list_global, &defobj, ve, 2164 flags, &donelist); 2165 } else { 2166 Needed_Entry fake; 2167 2168 /* Search the whole DAG rooted at the given object. */ 2169 fake.next = NULL; 2170 fake.obj = (Obj_Entry *)obj; 2171 fake.name = 0; 2172 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2173 &donelist); 2174 } 2175 } 2176 2177 if (def != NULL) { 2178 rlock_release(rtld_bind_lock, lockstate); 2179 2180 /* 2181 * The value required by the caller is derived from the value 2182 * of the symbol. For the ia64 architecture, we need to 2183 * construct a function descriptor which the caller can use to 2184 * call the function with the right 'gp' value. For other 2185 * architectures and for non-functions, the value is simply 2186 * the relocated value of the symbol. 2187 */ 2188 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2189 return make_function_pointer(def, defobj); 2190 else 2191 return defobj->relocbase + def->st_value; 2192 } 2193 2194 _rtld_error("Undefined symbol \"%s\"", name); 2195 rlock_release(rtld_bind_lock, lockstate); 2196 return NULL; 2197 } 2198 2199 void * 2200 dlsym(void *handle, const char *name) 2201 { 2202 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2203 SYMLOOK_DLSYM); 2204 } 2205 2206 dlfunc_t 2207 dlfunc(void *handle, const char *name) 2208 { 2209 union { 2210 void *d; 2211 dlfunc_t f; 2212 } rv; 2213 2214 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2215 SYMLOOK_DLSYM); 2216 return (rv.f); 2217 } 2218 2219 void * 2220 dlvsym(void *handle, const char *name, const char *version) 2221 { 2222 Ver_Entry ventry; 2223 2224 ventry.name = version; 2225 ventry.file = NULL; 2226 ventry.hash = elf_hash(version); 2227 ventry.flags= 0; 2228 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2229 SYMLOOK_DLSYM); 2230 } 2231 2232 int 2233 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2234 { 2235 const Obj_Entry *obj; 2236 int lockstate; 2237 2238 lockstate = rlock_acquire(rtld_bind_lock); 2239 obj = obj_from_addr(addr); 2240 if (obj == NULL) { 2241 _rtld_error("No shared object contains address"); 2242 rlock_release(rtld_bind_lock, lockstate); 2243 return (0); 2244 } 2245 rtld_fill_dl_phdr_info(obj, phdr_info); 2246 rlock_release(rtld_bind_lock, lockstate); 2247 return (1); 2248 } 2249 2250 int 2251 dladdr(const void *addr, Dl_info *info) 2252 { 2253 const Obj_Entry *obj; 2254 const Elf_Sym *def; 2255 void *symbol_addr; 2256 unsigned long symoffset; 2257 int lockstate; 2258 2259 lockstate = rlock_acquire(rtld_bind_lock); 2260 obj = obj_from_addr(addr); 2261 if (obj == NULL) { 2262 _rtld_error("No shared object contains address"); 2263 rlock_release(rtld_bind_lock, lockstate); 2264 return 0; 2265 } 2266 info->dli_fname = obj->path; 2267 info->dli_fbase = obj->mapbase; 2268 info->dli_saddr = (void *)0; 2269 info->dli_sname = NULL; 2270 2271 /* 2272 * Walk the symbol list looking for the symbol whose address is 2273 * closest to the address sent in. 2274 */ 2275 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2276 def = obj->symtab + symoffset; 2277 2278 /* 2279 * For skip the symbol if st_shndx is either SHN_UNDEF or 2280 * SHN_COMMON. 2281 */ 2282 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2283 continue; 2284 2285 /* 2286 * If the symbol is greater than the specified address, or if it 2287 * is further away from addr than the current nearest symbol, 2288 * then reject it. 2289 */ 2290 symbol_addr = obj->relocbase + def->st_value; 2291 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2292 continue; 2293 2294 /* Update our idea of the nearest symbol. */ 2295 info->dli_sname = obj->strtab + def->st_name; 2296 info->dli_saddr = symbol_addr; 2297 2298 /* Exact match? */ 2299 if (info->dli_saddr == addr) 2300 break; 2301 } 2302 rlock_release(rtld_bind_lock, lockstate); 2303 return 1; 2304 } 2305 2306 int 2307 dlinfo(void *handle, int request, void *p) 2308 { 2309 const Obj_Entry *obj; 2310 int error, lockstate; 2311 2312 lockstate = rlock_acquire(rtld_bind_lock); 2313 2314 if (handle == NULL || handle == RTLD_SELF) { 2315 void *retaddr; 2316 2317 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2318 if ((obj = obj_from_addr(retaddr)) == NULL) 2319 _rtld_error("Cannot determine caller's shared object"); 2320 } else 2321 obj = dlcheck(handle); 2322 2323 if (obj == NULL) { 2324 rlock_release(rtld_bind_lock, lockstate); 2325 return (-1); 2326 } 2327 2328 error = 0; 2329 switch (request) { 2330 case RTLD_DI_LINKMAP: 2331 *((struct link_map const **)p) = &obj->linkmap; 2332 break; 2333 case RTLD_DI_ORIGIN: 2334 error = rtld_dirname(obj->path, p); 2335 break; 2336 2337 case RTLD_DI_SERINFOSIZE: 2338 case RTLD_DI_SERINFO: 2339 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2340 break; 2341 2342 default: 2343 _rtld_error("Invalid request %d passed to dlinfo()", request); 2344 error = -1; 2345 } 2346 2347 rlock_release(rtld_bind_lock, lockstate); 2348 2349 return (error); 2350 } 2351 2352 static void 2353 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2354 { 2355 2356 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2357 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2358 STAILQ_FIRST(&obj->names)->name : obj->path; 2359 phdr_info->dlpi_phdr = obj->phdr; 2360 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2361 phdr_info->dlpi_tls_modid = obj->tlsindex; 2362 phdr_info->dlpi_tls_data = obj->tlsinit; 2363 phdr_info->dlpi_adds = obj_loads; 2364 phdr_info->dlpi_subs = obj_loads - obj_count; 2365 } 2366 2367 int 2368 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2369 { 2370 struct dl_phdr_info phdr_info; 2371 const Obj_Entry *obj; 2372 int error, bind_lockstate, phdr_lockstate; 2373 2374 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2375 bind_lockstate = rlock_acquire(rtld_bind_lock); 2376 2377 error = 0; 2378 2379 for (obj = obj_list; obj != NULL; obj = obj->next) { 2380 rtld_fill_dl_phdr_info(obj, &phdr_info); 2381 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2382 break; 2383 2384 } 2385 rlock_release(rtld_bind_lock, bind_lockstate); 2386 wlock_release(rtld_phdr_lock, phdr_lockstate); 2387 2388 return (error); 2389 } 2390 2391 struct fill_search_info_args { 2392 int request; 2393 unsigned int flags; 2394 Dl_serinfo *serinfo; 2395 Dl_serpath *serpath; 2396 char *strspace; 2397 }; 2398 2399 static void * 2400 fill_search_info(const char *dir, size_t dirlen, void *param) 2401 { 2402 struct fill_search_info_args *arg; 2403 2404 arg = param; 2405 2406 if (arg->request == RTLD_DI_SERINFOSIZE) { 2407 arg->serinfo->dls_cnt ++; 2408 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2409 } else { 2410 struct dl_serpath *s_entry; 2411 2412 s_entry = arg->serpath; 2413 s_entry->dls_name = arg->strspace; 2414 s_entry->dls_flags = arg->flags; 2415 2416 strncpy(arg->strspace, dir, dirlen); 2417 arg->strspace[dirlen] = '\0'; 2418 2419 arg->strspace += dirlen + 1; 2420 arg->serpath++; 2421 } 2422 2423 return (NULL); 2424 } 2425 2426 static int 2427 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2428 { 2429 struct dl_serinfo _info; 2430 struct fill_search_info_args args; 2431 2432 args.request = RTLD_DI_SERINFOSIZE; 2433 args.serinfo = &_info; 2434 2435 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2436 _info.dls_cnt = 0; 2437 2438 path_enumerate(ld_library_path, fill_search_info, &args); 2439 path_enumerate(obj->rpath, fill_search_info, &args); 2440 path_enumerate(gethints(), fill_search_info, &args); 2441 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2442 2443 2444 if (request == RTLD_DI_SERINFOSIZE) { 2445 info->dls_size = _info.dls_size; 2446 info->dls_cnt = _info.dls_cnt; 2447 return (0); 2448 } 2449 2450 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2451 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2452 return (-1); 2453 } 2454 2455 args.request = RTLD_DI_SERINFO; 2456 args.serinfo = info; 2457 args.serpath = &info->dls_serpath[0]; 2458 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2459 2460 args.flags = LA_SER_LIBPATH; 2461 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2462 return (-1); 2463 2464 args.flags = LA_SER_RUNPATH; 2465 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2466 return (-1); 2467 2468 args.flags = LA_SER_CONFIG; 2469 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2470 return (-1); 2471 2472 args.flags = LA_SER_DEFAULT; 2473 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2474 return (-1); 2475 return (0); 2476 } 2477 2478 static int 2479 rtld_dirname(const char *path, char *bname) 2480 { 2481 const char *endp; 2482 2483 /* Empty or NULL string gets treated as "." */ 2484 if (path == NULL || *path == '\0') { 2485 bname[0] = '.'; 2486 bname[1] = '\0'; 2487 return (0); 2488 } 2489 2490 /* Strip trailing slashes */ 2491 endp = path + strlen(path) - 1; 2492 while (endp > path && *endp == '/') 2493 endp--; 2494 2495 /* Find the start of the dir */ 2496 while (endp > path && *endp != '/') 2497 endp--; 2498 2499 /* Either the dir is "/" or there are no slashes */ 2500 if (endp == path) { 2501 bname[0] = *endp == '/' ? '/' : '.'; 2502 bname[1] = '\0'; 2503 return (0); 2504 } else { 2505 do { 2506 endp--; 2507 } while (endp > path && *endp == '/'); 2508 } 2509 2510 if (endp - path + 2 > PATH_MAX) 2511 { 2512 _rtld_error("Filename is too long: %s", path); 2513 return(-1); 2514 } 2515 2516 strncpy(bname, path, endp - path + 1); 2517 bname[endp - path + 1] = '\0'; 2518 return (0); 2519 } 2520 2521 static int 2522 rtld_dirname_abs(const char *path, char *base) 2523 { 2524 char base_rel[PATH_MAX]; 2525 2526 if (rtld_dirname(path, base) == -1) 2527 return (-1); 2528 if (base[0] == '/') 2529 return (0); 2530 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2531 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2532 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2533 return (-1); 2534 strcpy(base, base_rel); 2535 return (0); 2536 } 2537 2538 static void 2539 linkmap_add(Obj_Entry *obj) 2540 { 2541 struct link_map *l = &obj->linkmap; 2542 struct link_map *prev; 2543 2544 obj->linkmap.l_name = obj->path; 2545 obj->linkmap.l_addr = obj->mapbase; 2546 obj->linkmap.l_ld = obj->dynamic; 2547 #ifdef __mips__ 2548 /* GDB needs load offset on MIPS to use the symbols */ 2549 obj->linkmap.l_offs = obj->relocbase; 2550 #endif 2551 2552 if (r_debug.r_map == NULL) { 2553 r_debug.r_map = l; 2554 return; 2555 } 2556 2557 /* 2558 * Scan to the end of the list, but not past the entry for the 2559 * dynamic linker, which we want to keep at the very end. 2560 */ 2561 for (prev = r_debug.r_map; 2562 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2563 prev = prev->l_next) 2564 ; 2565 2566 /* Link in the new entry. */ 2567 l->l_prev = prev; 2568 l->l_next = prev->l_next; 2569 if (l->l_next != NULL) 2570 l->l_next->l_prev = l; 2571 prev->l_next = l; 2572 } 2573 2574 static void 2575 linkmap_delete(Obj_Entry *obj) 2576 { 2577 struct link_map *l = &obj->linkmap; 2578 2579 if (l->l_prev == NULL) { 2580 if ((r_debug.r_map = l->l_next) != NULL) 2581 l->l_next->l_prev = NULL; 2582 return; 2583 } 2584 2585 if ((l->l_prev->l_next = l->l_next) != NULL) 2586 l->l_next->l_prev = l->l_prev; 2587 } 2588 2589 /* 2590 * Function for the debugger to set a breakpoint on to gain control. 2591 * 2592 * The two parameters allow the debugger to easily find and determine 2593 * what the runtime loader is doing and to whom it is doing it. 2594 * 2595 * When the loadhook trap is hit (r_debug_state, set at program 2596 * initialization), the arguments can be found on the stack: 2597 * 2598 * +8 struct link_map *m 2599 * +4 struct r_debug *rd 2600 * +0 RetAddr 2601 */ 2602 void 2603 r_debug_state(struct r_debug* rd, struct link_map *m) 2604 { 2605 } 2606 2607 /* 2608 * Get address of the pointer variable in the main program. 2609 */ 2610 static const void ** 2611 get_program_var_addr(const char *name) 2612 { 2613 const Obj_Entry *obj; 2614 unsigned long hash; 2615 2616 hash = elf_hash(name); 2617 for (obj = obj_main; obj != NULL; obj = obj->next) { 2618 const Elf_Sym *def; 2619 2620 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2621 const void **addr; 2622 2623 addr = (const void **)(obj->relocbase + def->st_value); 2624 return addr; 2625 } 2626 } 2627 return NULL; 2628 } 2629 2630 /* 2631 * Set a pointer variable in the main program to the given value. This 2632 * is used to set key variables such as "environ" before any of the 2633 * init functions are called. 2634 */ 2635 static void 2636 set_program_var(const char *name, const void *value) 2637 { 2638 const void **addr; 2639 2640 if ((addr = get_program_var_addr(name)) != NULL) { 2641 dbg("\"%s\": *%p <-- %p", name, addr, value); 2642 *addr = value; 2643 } 2644 } 2645 2646 /* 2647 * Given a symbol name in a referencing object, find the corresponding 2648 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2649 * no definition was found. Returns a pointer to the Obj_Entry of the 2650 * defining object via the reference parameter DEFOBJ_OUT. 2651 */ 2652 static const Elf_Sym * 2653 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2654 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2655 { 2656 DoneList donelist; 2657 const Elf_Sym *def; 2658 const Elf_Sym *symp; 2659 const Obj_Entry *obj; 2660 const Obj_Entry *defobj; 2661 const Objlist_Entry *elm; 2662 def = NULL; 2663 defobj = NULL; 2664 donelist_init(&donelist); 2665 2666 /* Look first in the referencing object if linked symbolically. */ 2667 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2668 symp = symlook_obj(name, hash, refobj, ventry, flags); 2669 if (symp != NULL) { 2670 def = symp; 2671 defobj = refobj; 2672 } 2673 } 2674 2675 /* Search all objects loaded at program start up. */ 2676 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2677 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2678 &donelist); 2679 if (symp != NULL && 2680 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2681 def = symp; 2682 defobj = obj; 2683 } 2684 } 2685 2686 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2687 STAILQ_FOREACH(elm, &list_global, link) { 2688 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2689 break; 2690 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2691 flags, &donelist); 2692 if (symp != NULL && 2693 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2694 def = symp; 2695 defobj = obj; 2696 } 2697 } 2698 2699 /* Search all dlopened DAGs containing the referencing object. */ 2700 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2701 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2702 break; 2703 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2704 flags, &donelist); 2705 if (symp != NULL && 2706 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2707 def = symp; 2708 defobj = obj; 2709 } 2710 } 2711 2712 /* 2713 * Search the dynamic linker itself, and possibly resolve the 2714 * symbol from there. This is how the application links to 2715 * dynamic linker services such as dlopen. 2716 */ 2717 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2718 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2719 if (symp != NULL) { 2720 def = symp; 2721 defobj = &obj_rtld; 2722 } 2723 } 2724 2725 if (def != NULL) 2726 *defobj_out = defobj; 2727 return def; 2728 } 2729 2730 static const Elf_Sym * 2731 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2732 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2733 DoneList *dlp) 2734 { 2735 const Elf_Sym *symp; 2736 const Elf_Sym *def; 2737 const Obj_Entry *defobj; 2738 const Objlist_Entry *elm; 2739 2740 def = NULL; 2741 defobj = NULL; 2742 STAILQ_FOREACH(elm, objlist, link) { 2743 if (donelist_check(dlp, elm->obj)) 2744 continue; 2745 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2746 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2747 def = symp; 2748 defobj = elm->obj; 2749 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2750 break; 2751 } 2752 } 2753 } 2754 if (def != NULL) 2755 *defobj_out = defobj; 2756 return def; 2757 } 2758 2759 /* 2760 * Search the symbol table of a shared object and all objects needed 2761 * by it for a symbol of the given name. Search order is 2762 * breadth-first. Returns a pointer to the symbol, or NULL if no 2763 * definition was found. 2764 */ 2765 static const Elf_Sym * 2766 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2767 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2768 DoneList *dlp) 2769 { 2770 const Elf_Sym *def, *def_w; 2771 const Needed_Entry *n; 2772 const Obj_Entry *obj, *defobj, *defobj1; 2773 2774 def = def_w = NULL; 2775 defobj = NULL; 2776 for (n = needed; n != NULL; n = n->next) { 2777 if ((obj = n->obj) == NULL || 2778 donelist_check(dlp, obj) || 2779 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2780 continue; 2781 defobj = obj; 2782 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2783 *defobj_out = defobj; 2784 return (def); 2785 } 2786 } 2787 /* 2788 * There we come when either symbol definition is not found in 2789 * directly needed objects, or found symbol is weak. 2790 */ 2791 for (n = needed; n != NULL; n = n->next) { 2792 if ((obj = n->obj) == NULL) 2793 continue; 2794 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2795 ventry, flags, dlp); 2796 if (def_w == NULL) 2797 continue; 2798 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2799 def = def_w; 2800 defobj = defobj1; 2801 } 2802 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2803 break; 2804 } 2805 if (def != NULL) 2806 *defobj_out = defobj; 2807 return (def); 2808 } 2809 2810 /* 2811 * Search the symbol table of a single shared object for a symbol of 2812 * the given name and version, if requested. Returns a pointer to the 2813 * symbol, or NULL if no definition was found. 2814 * 2815 * The symbol's hash value is passed in for efficiency reasons; that 2816 * eliminates many recomputations of the hash value. 2817 */ 2818 const Elf_Sym * 2819 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2820 const Ver_Entry *ventry, int flags) 2821 { 2822 unsigned long symnum; 2823 const Elf_Sym *vsymp; 2824 Elf_Versym verndx; 2825 int vcount; 2826 2827 if (obj->buckets == NULL) 2828 return NULL; 2829 2830 vsymp = NULL; 2831 vcount = 0; 2832 symnum = obj->buckets[hash % obj->nbuckets]; 2833 2834 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2835 const Elf_Sym *symp; 2836 const char *strp; 2837 2838 if (symnum >= obj->nchains) 2839 return NULL; /* Bad object */ 2840 2841 symp = obj->symtab + symnum; 2842 strp = obj->strtab + symp->st_name; 2843 2844 switch (ELF_ST_TYPE(symp->st_info)) { 2845 case STT_FUNC: 2846 case STT_NOTYPE: 2847 case STT_OBJECT: 2848 if (symp->st_value == 0) 2849 continue; 2850 /* fallthrough */ 2851 case STT_TLS: 2852 if (symp->st_shndx != SHN_UNDEF) 2853 break; 2854 #ifndef __mips__ 2855 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2856 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2857 break; 2858 /* fallthrough */ 2859 #endif 2860 default: 2861 continue; 2862 } 2863 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2864 continue; 2865 2866 if (ventry == NULL) { 2867 if (obj->versyms != NULL) { 2868 verndx = VER_NDX(obj->versyms[symnum]); 2869 if (verndx > obj->vernum) { 2870 _rtld_error("%s: symbol %s references wrong version %d", 2871 obj->path, obj->strtab + symnum, verndx); 2872 continue; 2873 } 2874 /* 2875 * If we are not called from dlsym (i.e. this is a normal 2876 * relocation from unversioned binary, accept the symbol 2877 * immediately if it happens to have first version after 2878 * this shared object became versioned. Otherwise, if 2879 * symbol is versioned and not hidden, remember it. If it 2880 * is the only symbol with this name exported by the 2881 * shared object, it will be returned as a match at the 2882 * end of the function. If symbol is global (verndx < 2) 2883 * accept it unconditionally. 2884 */ 2885 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2886 return symp; 2887 else if (verndx >= VER_NDX_GIVEN) { 2888 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2889 if (vsymp == NULL) 2890 vsymp = symp; 2891 vcount ++; 2892 } 2893 continue; 2894 } 2895 } 2896 return symp; 2897 } else { 2898 if (obj->versyms == NULL) { 2899 if (object_match_name(obj, ventry->name)) { 2900 _rtld_error("%s: object %s should provide version %s for " 2901 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2902 obj->strtab + symnum); 2903 continue; 2904 } 2905 } else { 2906 verndx = VER_NDX(obj->versyms[symnum]); 2907 if (verndx > obj->vernum) { 2908 _rtld_error("%s: symbol %s references wrong version %d", 2909 obj->path, obj->strtab + symnum, verndx); 2910 continue; 2911 } 2912 if (obj->vertab[verndx].hash != ventry->hash || 2913 strcmp(obj->vertab[verndx].name, ventry->name)) { 2914 /* 2915 * Version does not match. Look if this is a global symbol 2916 * and if it is not hidden. If global symbol (verndx < 2) 2917 * is available, use it. Do not return symbol if we are 2918 * called by dlvsym, because dlvsym looks for a specific 2919 * version and default one is not what dlvsym wants. 2920 */ 2921 if ((flags & SYMLOOK_DLSYM) || 2922 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2923 (verndx >= VER_NDX_GIVEN)) 2924 continue; 2925 } 2926 } 2927 return symp; 2928 } 2929 } 2930 return (vcount == 1) ? vsymp : NULL; 2931 } 2932 2933 static void 2934 trace_loaded_objects(Obj_Entry *obj) 2935 { 2936 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2937 int c; 2938 2939 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2940 main_local = ""; 2941 2942 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2943 fmt1 = "\t%o => %p (%x)\n"; 2944 2945 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2946 fmt2 = "\t%o (%x)\n"; 2947 2948 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2949 2950 for (; obj; obj = obj->next) { 2951 Needed_Entry *needed; 2952 char *name, *path; 2953 bool is_lib; 2954 2955 if (list_containers && obj->needed != NULL) 2956 printf("%s:\n", obj->path); 2957 for (needed = obj->needed; needed; needed = needed->next) { 2958 if (needed->obj != NULL) { 2959 if (needed->obj->traced && !list_containers) 2960 continue; 2961 needed->obj->traced = true; 2962 path = needed->obj->path; 2963 } else 2964 path = "not found"; 2965 2966 name = (char *)obj->strtab + needed->name; 2967 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2968 2969 fmt = is_lib ? fmt1 : fmt2; 2970 while ((c = *fmt++) != '\0') { 2971 switch (c) { 2972 default: 2973 putchar(c); 2974 continue; 2975 case '\\': 2976 switch (c = *fmt) { 2977 case '\0': 2978 continue; 2979 case 'n': 2980 putchar('\n'); 2981 break; 2982 case 't': 2983 putchar('\t'); 2984 break; 2985 } 2986 break; 2987 case '%': 2988 switch (c = *fmt) { 2989 case '\0': 2990 continue; 2991 case '%': 2992 default: 2993 putchar(c); 2994 break; 2995 case 'A': 2996 printf("%s", main_local); 2997 break; 2998 case 'a': 2999 printf("%s", obj_main->path); 3000 break; 3001 case 'o': 3002 printf("%s", name); 3003 break; 3004 #if 0 3005 case 'm': 3006 printf("%d", sodp->sod_major); 3007 break; 3008 case 'n': 3009 printf("%d", sodp->sod_minor); 3010 break; 3011 #endif 3012 case 'p': 3013 printf("%s", path); 3014 break; 3015 case 'x': 3016 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3017 break; 3018 } 3019 break; 3020 } 3021 ++fmt; 3022 } 3023 } 3024 } 3025 } 3026 3027 /* 3028 * Unload a dlopened object and its dependencies from memory and from 3029 * our data structures. It is assumed that the DAG rooted in the 3030 * object has already been unreferenced, and that the object has a 3031 * reference count of 0. 3032 */ 3033 static void 3034 unload_object(Obj_Entry *root) 3035 { 3036 Obj_Entry *obj; 3037 Obj_Entry **linkp; 3038 3039 assert(root->refcount == 0); 3040 3041 /* 3042 * Pass over the DAG removing unreferenced objects from 3043 * appropriate lists. 3044 */ 3045 unlink_object(root); 3046 3047 /* Unmap all objects that are no longer referenced. */ 3048 linkp = &obj_list->next; 3049 while ((obj = *linkp) != NULL) { 3050 if (obj->refcount == 0) { 3051 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3052 obj->path); 3053 dbg("unloading \"%s\"", obj->path); 3054 munmap(obj->mapbase, obj->mapsize); 3055 linkmap_delete(obj); 3056 *linkp = obj->next; 3057 obj_count--; 3058 obj_free(obj); 3059 } else 3060 linkp = &obj->next; 3061 } 3062 obj_tail = linkp; 3063 } 3064 3065 static void 3066 unlink_object(Obj_Entry *root) 3067 { 3068 Objlist_Entry *elm; 3069 3070 if (root->refcount == 0) { 3071 /* Remove the object from the RTLD_GLOBAL list. */ 3072 objlist_remove(&list_global, root); 3073 3074 /* Remove the object from all objects' DAG lists. */ 3075 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3076 objlist_remove(&elm->obj->dldags, root); 3077 if (elm->obj != root) 3078 unlink_object(elm->obj); 3079 } 3080 } 3081 } 3082 3083 static void 3084 ref_dag(Obj_Entry *root) 3085 { 3086 Objlist_Entry *elm; 3087 3088 STAILQ_FOREACH(elm, &root->dagmembers, link) 3089 elm->obj->refcount++; 3090 } 3091 3092 static void 3093 unref_dag(Obj_Entry *root) 3094 { 3095 Objlist_Entry *elm; 3096 3097 STAILQ_FOREACH(elm, &root->dagmembers, link) 3098 elm->obj->refcount--; 3099 } 3100 3101 /* 3102 * Common code for MD __tls_get_addr(). 3103 */ 3104 void * 3105 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3106 { 3107 Elf_Addr* dtv = *dtvp; 3108 int lockstate; 3109 3110 /* Check dtv generation in case new modules have arrived */ 3111 if (dtv[0] != tls_dtv_generation) { 3112 Elf_Addr* newdtv; 3113 int to_copy; 3114 3115 lockstate = wlock_acquire(rtld_bind_lock); 3116 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3117 to_copy = dtv[1]; 3118 if (to_copy > tls_max_index) 3119 to_copy = tls_max_index; 3120 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3121 newdtv[0] = tls_dtv_generation; 3122 newdtv[1] = tls_max_index; 3123 free(dtv); 3124 wlock_release(rtld_bind_lock, lockstate); 3125 *dtvp = newdtv; 3126 } 3127 3128 /* Dynamically allocate module TLS if necessary */ 3129 if (!dtv[index + 1]) { 3130 /* Signal safe, wlock will block out signals. */ 3131 lockstate = wlock_acquire(rtld_bind_lock); 3132 if (!dtv[index + 1]) 3133 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3134 wlock_release(rtld_bind_lock, lockstate); 3135 } 3136 return (void*) (dtv[index + 1] + offset); 3137 } 3138 3139 /* XXX not sure what variants to use for arm. */ 3140 3141 #if defined(__ia64__) || defined(__powerpc__) 3142 3143 /* 3144 * Allocate Static TLS using the Variant I method. 3145 */ 3146 void * 3147 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3148 { 3149 Obj_Entry *obj; 3150 char *tcb; 3151 Elf_Addr **tls; 3152 Elf_Addr *dtv; 3153 Elf_Addr addr; 3154 int i; 3155 3156 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3157 return (oldtcb); 3158 3159 assert(tcbsize >= TLS_TCB_SIZE); 3160 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3161 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3162 3163 if (oldtcb != NULL) { 3164 memcpy(tls, oldtcb, tls_static_space); 3165 free(oldtcb); 3166 3167 /* Adjust the DTV. */ 3168 dtv = tls[0]; 3169 for (i = 0; i < dtv[1]; i++) { 3170 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3171 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3172 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3173 } 3174 } 3175 } else { 3176 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3177 tls[0] = dtv; 3178 dtv[0] = tls_dtv_generation; 3179 dtv[1] = tls_max_index; 3180 3181 for (obj = objs; obj; obj = obj->next) { 3182 if (obj->tlsoffset > 0) { 3183 addr = (Elf_Addr)tls + obj->tlsoffset; 3184 if (obj->tlsinitsize > 0) 3185 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3186 if (obj->tlssize > obj->tlsinitsize) 3187 memset((void*) (addr + obj->tlsinitsize), 0, 3188 obj->tlssize - obj->tlsinitsize); 3189 dtv[obj->tlsindex + 1] = addr; 3190 } 3191 } 3192 } 3193 3194 return (tcb); 3195 } 3196 3197 void 3198 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3199 { 3200 Elf_Addr *dtv; 3201 Elf_Addr tlsstart, tlsend; 3202 int dtvsize, i; 3203 3204 assert(tcbsize >= TLS_TCB_SIZE); 3205 3206 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3207 tlsend = tlsstart + tls_static_space; 3208 3209 dtv = *(Elf_Addr **)tlsstart; 3210 dtvsize = dtv[1]; 3211 for (i = 0; i < dtvsize; i++) { 3212 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3213 free((void*)dtv[i+2]); 3214 } 3215 } 3216 free(dtv); 3217 free(tcb); 3218 } 3219 3220 #endif 3221 3222 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3223 defined(__arm__) || defined(__mips__) 3224 3225 /* 3226 * Allocate Static TLS using the Variant II method. 3227 */ 3228 void * 3229 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3230 { 3231 Obj_Entry *obj; 3232 size_t size; 3233 char *tls; 3234 Elf_Addr *dtv, *olddtv; 3235 Elf_Addr segbase, oldsegbase, addr; 3236 int i; 3237 3238 size = round(tls_static_space, tcbalign); 3239 3240 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3241 tls = calloc(1, size + tcbsize); 3242 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3243 3244 segbase = (Elf_Addr)(tls + size); 3245 ((Elf_Addr*)segbase)[0] = segbase; 3246 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3247 3248 dtv[0] = tls_dtv_generation; 3249 dtv[1] = tls_max_index; 3250 3251 if (oldtls) { 3252 /* 3253 * Copy the static TLS block over whole. 3254 */ 3255 oldsegbase = (Elf_Addr) oldtls; 3256 memcpy((void *)(segbase - tls_static_space), 3257 (const void *)(oldsegbase - tls_static_space), 3258 tls_static_space); 3259 3260 /* 3261 * If any dynamic TLS blocks have been created tls_get_addr(), 3262 * move them over. 3263 */ 3264 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3265 for (i = 0; i < olddtv[1]; i++) { 3266 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3267 dtv[i+2] = olddtv[i+2]; 3268 olddtv[i+2] = 0; 3269 } 3270 } 3271 3272 /* 3273 * We assume that this block was the one we created with 3274 * allocate_initial_tls(). 3275 */ 3276 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3277 } else { 3278 for (obj = objs; obj; obj = obj->next) { 3279 if (obj->tlsoffset) { 3280 addr = segbase - obj->tlsoffset; 3281 memset((void*) (addr + obj->tlsinitsize), 3282 0, obj->tlssize - obj->tlsinitsize); 3283 if (obj->tlsinit) 3284 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3285 dtv[obj->tlsindex + 1] = addr; 3286 } 3287 } 3288 } 3289 3290 return (void*) segbase; 3291 } 3292 3293 void 3294 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3295 { 3296 size_t size; 3297 Elf_Addr* dtv; 3298 int dtvsize, i; 3299 Elf_Addr tlsstart, tlsend; 3300 3301 /* 3302 * Figure out the size of the initial TLS block so that we can 3303 * find stuff which ___tls_get_addr() allocated dynamically. 3304 */ 3305 size = round(tls_static_space, tcbalign); 3306 3307 dtv = ((Elf_Addr**)tls)[1]; 3308 dtvsize = dtv[1]; 3309 tlsend = (Elf_Addr) tls; 3310 tlsstart = tlsend - size; 3311 for (i = 0; i < dtvsize; i++) { 3312 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3313 free((void*) dtv[i+2]); 3314 } 3315 } 3316 3317 free((void*) tlsstart); 3318 free((void*) dtv); 3319 } 3320 3321 #endif 3322 3323 /* 3324 * Allocate TLS block for module with given index. 3325 */ 3326 void * 3327 allocate_module_tls(int index) 3328 { 3329 Obj_Entry* obj; 3330 char* p; 3331 3332 for (obj = obj_list; obj; obj = obj->next) { 3333 if (obj->tlsindex == index) 3334 break; 3335 } 3336 if (!obj) { 3337 _rtld_error("Can't find module with TLS index %d", index); 3338 die(); 3339 } 3340 3341 p = malloc(obj->tlssize); 3342 if (p == NULL) { 3343 _rtld_error("Cannot allocate TLS block for index %d", index); 3344 die(); 3345 } 3346 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3347 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3348 3349 return p; 3350 } 3351 3352 bool 3353 allocate_tls_offset(Obj_Entry *obj) 3354 { 3355 size_t off; 3356 3357 if (obj->tls_done) 3358 return true; 3359 3360 if (obj->tlssize == 0) { 3361 obj->tls_done = true; 3362 return true; 3363 } 3364 3365 if (obj->tlsindex == 1) 3366 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3367 else 3368 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3369 obj->tlssize, obj->tlsalign); 3370 3371 /* 3372 * If we have already fixed the size of the static TLS block, we 3373 * must stay within that size. When allocating the static TLS, we 3374 * leave a small amount of space spare to be used for dynamically 3375 * loading modules which use static TLS. 3376 */ 3377 if (tls_static_space) { 3378 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3379 return false; 3380 } 3381 3382 tls_last_offset = obj->tlsoffset = off; 3383 tls_last_size = obj->tlssize; 3384 obj->tls_done = true; 3385 3386 return true; 3387 } 3388 3389 void 3390 free_tls_offset(Obj_Entry *obj) 3391 { 3392 3393 /* 3394 * If we were the last thing to allocate out of the static TLS 3395 * block, we give our space back to the 'allocator'. This is a 3396 * simplistic workaround to allow libGL.so.1 to be loaded and 3397 * unloaded multiple times. 3398 */ 3399 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3400 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3401 tls_last_offset -= obj->tlssize; 3402 tls_last_size = 0; 3403 } 3404 } 3405 3406 void * 3407 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3408 { 3409 void *ret; 3410 int lockstate; 3411 3412 lockstate = wlock_acquire(rtld_bind_lock); 3413 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3414 wlock_release(rtld_bind_lock, lockstate); 3415 return (ret); 3416 } 3417 3418 void 3419 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3420 { 3421 int lockstate; 3422 3423 lockstate = wlock_acquire(rtld_bind_lock); 3424 free_tls(tcb, tcbsize, tcbalign); 3425 wlock_release(rtld_bind_lock, lockstate); 3426 } 3427 3428 static void 3429 object_add_name(Obj_Entry *obj, const char *name) 3430 { 3431 Name_Entry *entry; 3432 size_t len; 3433 3434 len = strlen(name); 3435 entry = malloc(sizeof(Name_Entry) + len); 3436 3437 if (entry != NULL) { 3438 strcpy(entry->name, name); 3439 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3440 } 3441 } 3442 3443 static int 3444 object_match_name(const Obj_Entry *obj, const char *name) 3445 { 3446 Name_Entry *entry; 3447 3448 STAILQ_FOREACH(entry, &obj->names, link) { 3449 if (strcmp(name, entry->name) == 0) 3450 return (1); 3451 } 3452 return (0); 3453 } 3454 3455 static Obj_Entry * 3456 locate_dependency(const Obj_Entry *obj, const char *name) 3457 { 3458 const Objlist_Entry *entry; 3459 const Needed_Entry *needed; 3460 3461 STAILQ_FOREACH(entry, &list_main, link) { 3462 if (object_match_name(entry->obj, name)) 3463 return entry->obj; 3464 } 3465 3466 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3467 if (needed->obj == NULL) 3468 continue; 3469 if (object_match_name(needed->obj, name)) 3470 return needed->obj; 3471 } 3472 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3473 obj->path, name); 3474 die(); 3475 } 3476 3477 static int 3478 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3479 const Elf_Vernaux *vna) 3480 { 3481 const Elf_Verdef *vd; 3482 const char *vername; 3483 3484 vername = refobj->strtab + vna->vna_name; 3485 vd = depobj->verdef; 3486 if (vd == NULL) { 3487 _rtld_error("%s: version %s required by %s not defined", 3488 depobj->path, vername, refobj->path); 3489 return (-1); 3490 } 3491 for (;;) { 3492 if (vd->vd_version != VER_DEF_CURRENT) { 3493 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3494 depobj->path, vd->vd_version); 3495 return (-1); 3496 } 3497 if (vna->vna_hash == vd->vd_hash) { 3498 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3499 ((char *)vd + vd->vd_aux); 3500 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3501 return (0); 3502 } 3503 if (vd->vd_next == 0) 3504 break; 3505 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3506 } 3507 if (vna->vna_flags & VER_FLG_WEAK) 3508 return (0); 3509 _rtld_error("%s: version %s required by %s not found", 3510 depobj->path, vername, refobj->path); 3511 return (-1); 3512 } 3513 3514 static int 3515 rtld_verify_object_versions(Obj_Entry *obj) 3516 { 3517 const Elf_Verneed *vn; 3518 const Elf_Verdef *vd; 3519 const Elf_Verdaux *vda; 3520 const Elf_Vernaux *vna; 3521 const Obj_Entry *depobj; 3522 int maxvernum, vernum; 3523 3524 maxvernum = 0; 3525 /* 3526 * Walk over defined and required version records and figure out 3527 * max index used by any of them. Do very basic sanity checking 3528 * while there. 3529 */ 3530 vn = obj->verneed; 3531 while (vn != NULL) { 3532 if (vn->vn_version != VER_NEED_CURRENT) { 3533 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3534 obj->path, vn->vn_version); 3535 return (-1); 3536 } 3537 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3538 for (;;) { 3539 vernum = VER_NEED_IDX(vna->vna_other); 3540 if (vernum > maxvernum) 3541 maxvernum = vernum; 3542 if (vna->vna_next == 0) 3543 break; 3544 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3545 } 3546 if (vn->vn_next == 0) 3547 break; 3548 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3549 } 3550 3551 vd = obj->verdef; 3552 while (vd != NULL) { 3553 if (vd->vd_version != VER_DEF_CURRENT) { 3554 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3555 obj->path, vd->vd_version); 3556 return (-1); 3557 } 3558 vernum = VER_DEF_IDX(vd->vd_ndx); 3559 if (vernum > maxvernum) 3560 maxvernum = vernum; 3561 if (vd->vd_next == 0) 3562 break; 3563 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3564 } 3565 3566 if (maxvernum == 0) 3567 return (0); 3568 3569 /* 3570 * Store version information in array indexable by version index. 3571 * Verify that object version requirements are satisfied along the 3572 * way. 3573 */ 3574 obj->vernum = maxvernum + 1; 3575 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3576 3577 vd = obj->verdef; 3578 while (vd != NULL) { 3579 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3580 vernum = VER_DEF_IDX(vd->vd_ndx); 3581 assert(vernum <= maxvernum); 3582 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3583 obj->vertab[vernum].hash = vd->vd_hash; 3584 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3585 obj->vertab[vernum].file = NULL; 3586 obj->vertab[vernum].flags = 0; 3587 } 3588 if (vd->vd_next == 0) 3589 break; 3590 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3591 } 3592 3593 vn = obj->verneed; 3594 while (vn != NULL) { 3595 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3596 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3597 for (;;) { 3598 if (check_object_provided_version(obj, depobj, vna)) 3599 return (-1); 3600 vernum = VER_NEED_IDX(vna->vna_other); 3601 assert(vernum <= maxvernum); 3602 obj->vertab[vernum].hash = vna->vna_hash; 3603 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3604 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3605 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3606 VER_INFO_HIDDEN : 0; 3607 if (vna->vna_next == 0) 3608 break; 3609 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3610 } 3611 if (vn->vn_next == 0) 3612 break; 3613 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3614 } 3615 return 0; 3616 } 3617 3618 static int 3619 rtld_verify_versions(const Objlist *objlist) 3620 { 3621 Objlist_Entry *entry; 3622 int rc; 3623 3624 rc = 0; 3625 STAILQ_FOREACH(entry, objlist, link) { 3626 /* 3627 * Skip dummy objects or objects that have their version requirements 3628 * already checked. 3629 */ 3630 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3631 continue; 3632 if (rtld_verify_object_versions(entry->obj) == -1) { 3633 rc = -1; 3634 if (ld_tracing == NULL) 3635 break; 3636 } 3637 } 3638 if (rc == 0 || ld_tracing != NULL) 3639 rc = rtld_verify_object_versions(&obj_rtld); 3640 return rc; 3641 } 3642 3643 const Ver_Entry * 3644 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3645 { 3646 Elf_Versym vernum; 3647 3648 if (obj->vertab) { 3649 vernum = VER_NDX(obj->versyms[symnum]); 3650 if (vernum >= obj->vernum) { 3651 _rtld_error("%s: symbol %s has wrong verneed value %d", 3652 obj->path, obj->strtab + symnum, vernum); 3653 } else if (obj->vertab[vernum].hash != 0) { 3654 return &obj->vertab[vernum]; 3655 } 3656 } 3657 return NULL; 3658 } 3659 3660 /* 3661 * Overrides for libc_pic-provided functions. 3662 */ 3663 3664 int 3665 __getosreldate(void) 3666 { 3667 size_t len; 3668 int oid[2]; 3669 int error, osrel; 3670 3671 if (osreldate != 0) 3672 return (osreldate); 3673 3674 oid[0] = CTL_KERN; 3675 oid[1] = KERN_OSRELDATE; 3676 osrel = 0; 3677 len = sizeof(osrel); 3678 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 3679 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 3680 osreldate = osrel; 3681 return (osreldate); 3682 } 3683 3684 /* 3685 * No unresolved symbols for rtld. 3686 */ 3687 void 3688 __pthread_cxa_finalize(struct dl_phdr_info *a) 3689 { 3690 } 3691