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 objlist_push_tail(&obj->dldags, root); 1294 objlist_push_tail(&root->dagmembers, obj); 1295 for (needed = obj->needed; needed != NULL; needed = needed->next) 1296 if (needed->obj != NULL) 1297 init_dag1(root, needed->obj, dlp); 1298 } 1299 1300 /* 1301 * Initialize the dynamic linker. The argument is the address at which 1302 * the dynamic linker has been mapped into memory. The primary task of 1303 * this function is to relocate the dynamic linker. 1304 */ 1305 static void 1306 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1307 { 1308 Obj_Entry objtmp; /* Temporary rtld object */ 1309 const Elf_Dyn *dyn_rpath; 1310 const Elf_Dyn *dyn_soname; 1311 1312 /* 1313 * Conjure up an Obj_Entry structure for the dynamic linker. 1314 * 1315 * The "path" member can't be initialized yet because string constants 1316 * cannot yet be accessed. Below we will set it correctly. 1317 */ 1318 memset(&objtmp, 0, sizeof(objtmp)); 1319 objtmp.path = NULL; 1320 objtmp.rtld = true; 1321 objtmp.mapbase = mapbase; 1322 #ifdef PIC 1323 objtmp.relocbase = mapbase; 1324 #endif 1325 if (RTLD_IS_DYNAMIC()) { 1326 objtmp.dynamic = rtld_dynamic(&objtmp); 1327 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1328 assert(objtmp.needed == NULL); 1329 #if !defined(__mips__) 1330 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1331 assert(!objtmp.textrel); 1332 #endif 1333 1334 /* 1335 * Temporarily put the dynamic linker entry into the object list, so 1336 * that symbols can be found. 1337 */ 1338 1339 relocate_objects(&objtmp, true, &objtmp); 1340 } 1341 1342 /* Initialize the object list. */ 1343 obj_tail = &obj_list; 1344 1345 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1346 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1347 1348 if (aux_info[AT_PAGESZ] != NULL) 1349 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1350 if (aux_info[AT_OSRELDATE] != NULL) 1351 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1352 1353 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1354 1355 /* Replace the path with a dynamically allocated copy. */ 1356 obj_rtld.path = xstrdup(PATH_RTLD); 1357 1358 r_debug.r_brk = r_debug_state; 1359 r_debug.r_state = RT_CONSISTENT; 1360 } 1361 1362 /* 1363 * Add the init functions from a needed object list (and its recursive 1364 * needed objects) to "list". This is not used directly; it is a helper 1365 * function for initlist_add_objects(). The write lock must be held 1366 * when this function is called. 1367 */ 1368 static void 1369 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1370 { 1371 /* Recursively process the successor needed objects. */ 1372 if (needed->next != NULL) 1373 initlist_add_neededs(needed->next, list); 1374 1375 /* Process the current needed object. */ 1376 if (needed->obj != NULL) 1377 initlist_add_objects(needed->obj, &needed->obj->next, list); 1378 } 1379 1380 /* 1381 * Scan all of the DAGs rooted in the range of objects from "obj" to 1382 * "tail" and add their init functions to "list". This recurses over 1383 * the DAGs and ensure the proper init ordering such that each object's 1384 * needed libraries are initialized before the object itself. At the 1385 * same time, this function adds the objects to the global finalization 1386 * list "list_fini" in the opposite order. The write lock must be 1387 * held when this function is called. 1388 */ 1389 static void 1390 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1391 { 1392 if (obj->init_scanned || obj->init_done) 1393 return; 1394 obj->init_scanned = true; 1395 1396 /* Recursively process the successor objects. */ 1397 if (&obj->next != tail) 1398 initlist_add_objects(obj->next, tail, list); 1399 1400 /* Recursively process the needed objects. */ 1401 if (obj->needed != NULL) 1402 initlist_add_neededs(obj->needed, list); 1403 1404 /* Add the object to the init list. */ 1405 if (obj->init != (Elf_Addr)NULL) 1406 objlist_push_tail(list, obj); 1407 1408 /* Add the object to the global fini list in the reverse order. */ 1409 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1410 objlist_push_head(&list_fini, obj); 1411 obj->on_fini_list = true; 1412 } 1413 } 1414 1415 #ifndef FPTR_TARGET 1416 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1417 #endif 1418 1419 /* 1420 * Given a shared object, traverse its list of needed objects, and load 1421 * each of them. Returns 0 on success. Generates an error message and 1422 * returns -1 on failure. 1423 */ 1424 static int 1425 load_needed_objects(Obj_Entry *first, int flags) 1426 { 1427 Obj_Entry *obj, *obj1; 1428 1429 for (obj = first; obj != NULL; obj = obj->next) { 1430 Needed_Entry *needed; 1431 1432 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1433 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1434 flags & ~RTLD_LO_NOLOAD); 1435 if (obj1 == NULL && !ld_tracing) 1436 return -1; 1437 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1438 dbg("obj %s nodelete", obj1->path); 1439 init_dag(obj1); 1440 ref_dag(obj1); 1441 obj1->ref_nodel = true; 1442 } 1443 } 1444 } 1445 1446 return 0; 1447 } 1448 1449 static int 1450 load_preload_objects(void) 1451 { 1452 char *p = ld_preload; 1453 static const char delim[] = " \t:;"; 1454 1455 if (p == NULL) 1456 return 0; 1457 1458 p += strspn(p, delim); 1459 while (*p != '\0') { 1460 size_t len = strcspn(p, delim); 1461 char savech; 1462 1463 savech = p[len]; 1464 p[len] = '\0'; 1465 if (load_object(p, NULL, 0) == NULL) 1466 return -1; /* XXX - cleanup */ 1467 p[len] = savech; 1468 p += len; 1469 p += strspn(p, delim); 1470 } 1471 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1472 return 0; 1473 } 1474 1475 /* 1476 * Load a shared object into memory, if it is not already loaded. 1477 * 1478 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1479 * on failure. 1480 */ 1481 static Obj_Entry * 1482 load_object(const char *name, const Obj_Entry *refobj, int flags) 1483 { 1484 Obj_Entry *obj; 1485 int fd = -1; 1486 struct stat sb; 1487 char *path; 1488 1489 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1490 if (object_match_name(obj, name)) 1491 return obj; 1492 1493 path = find_library(name, refobj); 1494 if (path == NULL) 1495 return NULL; 1496 1497 /* 1498 * If we didn't find a match by pathname, open the file and check 1499 * again by device and inode. This avoids false mismatches caused 1500 * by multiple links or ".." in pathnames. 1501 * 1502 * To avoid a race, we open the file and use fstat() rather than 1503 * using stat(). 1504 */ 1505 if ((fd = open(path, O_RDONLY)) == -1) { 1506 _rtld_error("Cannot open \"%s\"", path); 1507 free(path); 1508 return NULL; 1509 } 1510 if (fstat(fd, &sb) == -1) { 1511 _rtld_error("Cannot fstat \"%s\"", path); 1512 close(fd); 1513 free(path); 1514 return NULL; 1515 } 1516 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1517 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1518 close(fd); 1519 break; 1520 } 1521 } 1522 if (obj != NULL) { 1523 object_add_name(obj, name); 1524 free(path); 1525 close(fd); 1526 return obj; 1527 } 1528 if (flags & RTLD_LO_NOLOAD) { 1529 free(path); 1530 return (NULL); 1531 } 1532 1533 /* First use of this object, so we must map it in */ 1534 obj = do_load_object(fd, name, path, &sb, flags); 1535 if (obj == NULL) 1536 free(path); 1537 close(fd); 1538 1539 return obj; 1540 } 1541 1542 static Obj_Entry * 1543 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1544 int flags) 1545 { 1546 Obj_Entry *obj; 1547 struct statfs fs; 1548 1549 /* 1550 * but first, make sure that environment variables haven't been 1551 * used to circumvent the noexec flag on a filesystem. 1552 */ 1553 if (dangerous_ld_env) { 1554 if (fstatfs(fd, &fs) != 0) { 1555 _rtld_error("Cannot fstatfs \"%s\"", path); 1556 return NULL; 1557 } 1558 if (fs.f_flags & MNT_NOEXEC) { 1559 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1560 return NULL; 1561 } 1562 } 1563 dbg("loading \"%s\"", path); 1564 obj = map_object(fd, path, sbp); 1565 if (obj == NULL) 1566 return NULL; 1567 1568 object_add_name(obj, name); 1569 obj->path = path; 1570 digest_dynamic(obj, 0); 1571 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1572 RTLD_LO_DLOPEN) { 1573 dbg("refusing to load non-loadable \"%s\"", obj->path); 1574 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1575 munmap(obj->mapbase, obj->mapsize); 1576 obj_free(obj); 1577 return (NULL); 1578 } 1579 1580 *obj_tail = obj; 1581 obj_tail = &obj->next; 1582 obj_count++; 1583 obj_loads++; 1584 linkmap_add(obj); /* for GDB & dlinfo() */ 1585 1586 dbg(" %p .. %p: %s", obj->mapbase, 1587 obj->mapbase + obj->mapsize - 1, obj->path); 1588 if (obj->textrel) 1589 dbg(" WARNING: %s has impure text", obj->path); 1590 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1591 obj->path); 1592 1593 return obj; 1594 } 1595 1596 static Obj_Entry * 1597 obj_from_addr(const void *addr) 1598 { 1599 Obj_Entry *obj; 1600 1601 for (obj = obj_list; obj != NULL; obj = obj->next) { 1602 if (addr < (void *) obj->mapbase) 1603 continue; 1604 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1605 return obj; 1606 } 1607 return NULL; 1608 } 1609 1610 /* 1611 * Call the finalization functions for each of the objects in "list" 1612 * which are unreferenced. All of the objects are expected to have 1613 * non-NULL fini functions. 1614 */ 1615 static void 1616 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1617 { 1618 Objlist_Entry *elm, *elm_tmp; 1619 char *saved_msg; 1620 1621 /* 1622 * Preserve the current error message since a fini function might 1623 * call into the dynamic linker and overwrite it. 1624 */ 1625 saved_msg = errmsg_save(); 1626 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1627 if (elm->obj->refcount == 0 || force) { 1628 dbg("calling fini function for %s at %p", elm->obj->path, 1629 (void *)elm->obj->fini); 1630 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1631 elm->obj->path); 1632 /* Remove object from fini list to prevent recursive invocation. */ 1633 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1634 wlock_release(rtld_bind_lock, *lockstate); 1635 call_initfini_pointer(elm->obj, elm->obj->fini); 1636 *lockstate = wlock_acquire(rtld_bind_lock); 1637 /* No need to free anything if process is going down. */ 1638 if (!force) 1639 free(elm); 1640 } 1641 } 1642 errmsg_restore(saved_msg); 1643 } 1644 1645 /* 1646 * Call the initialization functions for each of the objects in 1647 * "list". All of the objects are expected to have non-NULL init 1648 * functions. 1649 */ 1650 static void 1651 objlist_call_init(Objlist *list, int *lockstate) 1652 { 1653 Objlist_Entry *elm; 1654 Obj_Entry *obj; 1655 char *saved_msg; 1656 1657 /* 1658 * Clean init_scanned flag so that objects can be rechecked and 1659 * possibly initialized earlier if any of vectors called below 1660 * cause the change by using dlopen. 1661 */ 1662 for (obj = obj_list; obj != NULL; obj = obj->next) 1663 obj->init_scanned = false; 1664 1665 /* 1666 * Preserve the current error message since an init function might 1667 * call into the dynamic linker and overwrite it. 1668 */ 1669 saved_msg = errmsg_save(); 1670 STAILQ_FOREACH(elm, list, link) { 1671 if (elm->obj->init_done) /* Initialized early. */ 1672 continue; 1673 dbg("calling init function for %s at %p", elm->obj->path, 1674 (void *)elm->obj->init); 1675 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1676 elm->obj->path); 1677 /* 1678 * Race: other thread might try to use this object before current 1679 * one completes the initilization. Not much can be done here 1680 * without better locking. 1681 */ 1682 elm->obj->init_done = true; 1683 wlock_release(rtld_bind_lock, *lockstate); 1684 call_initfini_pointer(elm->obj, elm->obj->init); 1685 *lockstate = wlock_acquire(rtld_bind_lock); 1686 } 1687 errmsg_restore(saved_msg); 1688 } 1689 1690 static void 1691 objlist_clear(Objlist *list) 1692 { 1693 Objlist_Entry *elm; 1694 1695 while (!STAILQ_EMPTY(list)) { 1696 elm = STAILQ_FIRST(list); 1697 STAILQ_REMOVE_HEAD(list, link); 1698 free(elm); 1699 } 1700 } 1701 1702 static Objlist_Entry * 1703 objlist_find(Objlist *list, const Obj_Entry *obj) 1704 { 1705 Objlist_Entry *elm; 1706 1707 STAILQ_FOREACH(elm, list, link) 1708 if (elm->obj == obj) 1709 return elm; 1710 return NULL; 1711 } 1712 1713 static void 1714 objlist_init(Objlist *list) 1715 { 1716 STAILQ_INIT(list); 1717 } 1718 1719 static void 1720 objlist_push_head(Objlist *list, Obj_Entry *obj) 1721 { 1722 Objlist_Entry *elm; 1723 1724 elm = NEW(Objlist_Entry); 1725 elm->obj = obj; 1726 STAILQ_INSERT_HEAD(list, elm, link); 1727 } 1728 1729 static void 1730 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1731 { 1732 Objlist_Entry *elm; 1733 1734 elm = NEW(Objlist_Entry); 1735 elm->obj = obj; 1736 STAILQ_INSERT_TAIL(list, elm, link); 1737 } 1738 1739 static void 1740 objlist_remove(Objlist *list, Obj_Entry *obj) 1741 { 1742 Objlist_Entry *elm; 1743 1744 if ((elm = objlist_find(list, obj)) != NULL) { 1745 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1746 free(elm); 1747 } 1748 } 1749 1750 /* 1751 * Relocate newly-loaded shared objects. The argument is a pointer to 1752 * the Obj_Entry for the first such object. All objects from the first 1753 * to the end of the list of objects are relocated. Returns 0 on success, 1754 * or -1 on failure. 1755 */ 1756 static int 1757 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1758 { 1759 Obj_Entry *obj; 1760 1761 for (obj = first; obj != NULL; obj = obj->next) { 1762 if (obj != rtldobj) 1763 dbg("relocating \"%s\"", obj->path); 1764 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1765 obj->symtab == NULL || obj->strtab == NULL) { 1766 _rtld_error("%s: Shared object has no run-time symbol table", 1767 obj->path); 1768 return -1; 1769 } 1770 1771 if (obj->textrel) { 1772 /* There are relocations to the write-protected text segment. */ 1773 if (mprotect(obj->mapbase, obj->textsize, 1774 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1775 _rtld_error("%s: Cannot write-enable text segment: %s", 1776 obj->path, strerror(errno)); 1777 return -1; 1778 } 1779 } 1780 1781 /* Process the non-PLT relocations. */ 1782 if (reloc_non_plt(obj, rtldobj)) 1783 return -1; 1784 1785 if (obj->textrel) { /* Re-protected the text segment. */ 1786 if (mprotect(obj->mapbase, obj->textsize, 1787 PROT_READ|PROT_EXEC) == -1) { 1788 _rtld_error("%s: Cannot write-protect text segment: %s", 1789 obj->path, strerror(errno)); 1790 return -1; 1791 } 1792 } 1793 1794 /* Process the PLT relocations. */ 1795 if (reloc_plt(obj) == -1) 1796 return -1; 1797 /* Relocate the jump slots if we are doing immediate binding. */ 1798 if (obj->bind_now || bind_now) 1799 if (reloc_jmpslots(obj) == -1) 1800 return -1; 1801 1802 1803 /* 1804 * Set up the magic number and version in the Obj_Entry. These 1805 * were checked in the crt1.o from the original ElfKit, so we 1806 * set them for backward compatibility. 1807 */ 1808 obj->magic = RTLD_MAGIC; 1809 obj->version = RTLD_VERSION; 1810 1811 /* Set the special PLT or GOT entries. */ 1812 init_pltgot(obj); 1813 } 1814 1815 return 0; 1816 } 1817 1818 /* 1819 * Cleanup procedure. It will be called (by the atexit mechanism) just 1820 * before the process exits. 1821 */ 1822 static void 1823 rtld_exit(void) 1824 { 1825 int lockstate; 1826 1827 lockstate = wlock_acquire(rtld_bind_lock); 1828 dbg("rtld_exit()"); 1829 objlist_call_fini(&list_fini, true, &lockstate); 1830 /* No need to remove the items from the list, since we are exiting. */ 1831 if (!libmap_disable) 1832 lm_fini(); 1833 wlock_release(rtld_bind_lock, lockstate); 1834 } 1835 1836 static void * 1837 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1838 { 1839 #ifdef COMPAT_32BIT 1840 const char *trans; 1841 #endif 1842 if (path == NULL) 1843 return (NULL); 1844 1845 path += strspn(path, ":;"); 1846 while (*path != '\0') { 1847 size_t len; 1848 char *res; 1849 1850 len = strcspn(path, ":;"); 1851 #ifdef COMPAT_32BIT 1852 trans = lm_findn(NULL, path, len); 1853 if (trans) 1854 res = callback(trans, strlen(trans), arg); 1855 else 1856 #endif 1857 res = callback(path, len, arg); 1858 1859 if (res != NULL) 1860 return (res); 1861 1862 path += len; 1863 path += strspn(path, ":;"); 1864 } 1865 1866 return (NULL); 1867 } 1868 1869 struct try_library_args { 1870 const char *name; 1871 size_t namelen; 1872 char *buffer; 1873 size_t buflen; 1874 }; 1875 1876 static void * 1877 try_library_path(const char *dir, size_t dirlen, void *param) 1878 { 1879 struct try_library_args *arg; 1880 1881 arg = param; 1882 if (*dir == '/' || trust) { 1883 char *pathname; 1884 1885 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1886 return (NULL); 1887 1888 pathname = arg->buffer; 1889 strncpy(pathname, dir, dirlen); 1890 pathname[dirlen] = '/'; 1891 strcpy(pathname + dirlen + 1, arg->name); 1892 1893 dbg(" Trying \"%s\"", pathname); 1894 if (access(pathname, F_OK) == 0) { /* We found it */ 1895 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1896 strcpy(pathname, arg->buffer); 1897 return (pathname); 1898 } 1899 } 1900 return (NULL); 1901 } 1902 1903 static char * 1904 search_library_path(const char *name, const char *path) 1905 { 1906 char *p; 1907 struct try_library_args arg; 1908 1909 if (path == NULL) 1910 return NULL; 1911 1912 arg.name = name; 1913 arg.namelen = strlen(name); 1914 arg.buffer = xmalloc(PATH_MAX); 1915 arg.buflen = PATH_MAX; 1916 1917 p = path_enumerate(path, try_library_path, &arg); 1918 1919 free(arg.buffer); 1920 1921 return (p); 1922 } 1923 1924 int 1925 dlclose(void *handle) 1926 { 1927 Obj_Entry *root; 1928 int lockstate; 1929 1930 lockstate = wlock_acquire(rtld_bind_lock); 1931 root = dlcheck(handle); 1932 if (root == NULL) { 1933 wlock_release(rtld_bind_lock, lockstate); 1934 return -1; 1935 } 1936 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1937 root->path); 1938 1939 /* Unreference the object and its dependencies. */ 1940 root->dl_refcount--; 1941 1942 unref_dag(root); 1943 1944 if (root->refcount == 0) { 1945 /* 1946 * The object is no longer referenced, so we must unload it. 1947 * First, call the fini functions. 1948 */ 1949 objlist_call_fini(&list_fini, false, &lockstate); 1950 1951 /* Finish cleaning up the newly-unreferenced objects. */ 1952 GDB_STATE(RT_DELETE,&root->linkmap); 1953 unload_object(root); 1954 GDB_STATE(RT_CONSISTENT,NULL); 1955 } 1956 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1957 wlock_release(rtld_bind_lock, lockstate); 1958 return 0; 1959 } 1960 1961 char * 1962 dlerror(void) 1963 { 1964 char *msg = error_message; 1965 error_message = NULL; 1966 return msg; 1967 } 1968 1969 /* 1970 * This function is deprecated and has no effect. 1971 */ 1972 void 1973 dllockinit(void *context, 1974 void *(*lock_create)(void *context), 1975 void (*rlock_acquire)(void *lock), 1976 void (*wlock_acquire)(void *lock), 1977 void (*lock_release)(void *lock), 1978 void (*lock_destroy)(void *lock), 1979 void (*context_destroy)(void *context)) 1980 { 1981 static void *cur_context; 1982 static void (*cur_context_destroy)(void *); 1983 1984 /* Just destroy the context from the previous call, if necessary. */ 1985 if (cur_context_destroy != NULL) 1986 cur_context_destroy(cur_context); 1987 cur_context = context; 1988 cur_context_destroy = context_destroy; 1989 } 1990 1991 void * 1992 dlopen(const char *name, int mode) 1993 { 1994 Obj_Entry **old_obj_tail; 1995 Obj_Entry *obj; 1996 Objlist initlist; 1997 int result, lockstate, nodelete, lo_flags; 1998 1999 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2000 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2001 if (ld_tracing != NULL) 2002 environ = (char **)*get_program_var_addr("environ"); 2003 nodelete = mode & RTLD_NODELETE; 2004 lo_flags = RTLD_LO_DLOPEN; 2005 if (mode & RTLD_NOLOAD) 2006 lo_flags |= RTLD_LO_NOLOAD; 2007 if (ld_tracing != NULL) 2008 lo_flags |= RTLD_LO_TRACE; 2009 2010 objlist_init(&initlist); 2011 2012 lockstate = wlock_acquire(rtld_bind_lock); 2013 GDB_STATE(RT_ADD,NULL); 2014 2015 old_obj_tail = obj_tail; 2016 obj = NULL; 2017 if (name == NULL) { 2018 obj = obj_main; 2019 obj->refcount++; 2020 } else { 2021 obj = load_object(name, obj_main, lo_flags); 2022 } 2023 2024 if (obj) { 2025 obj->dl_refcount++; 2026 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2027 objlist_push_tail(&list_global, obj); 2028 mode &= RTLD_MODEMASK; 2029 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2030 assert(*old_obj_tail == obj); 2031 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2032 init_dag(obj); 2033 ref_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 init_dag(obj); 2058 ref_dag(obj); 2059 2060 if (ld_tracing) 2061 goto trace; 2062 } 2063 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2064 dbg("obj %s nodelete", obj->path); 2065 ref_dag(obj); 2066 obj->z_nodelete = obj->ref_nodel = true; 2067 } 2068 } 2069 2070 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2071 name); 2072 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2073 2074 /* Call the init functions. */ 2075 objlist_call_init(&initlist, &lockstate); 2076 objlist_clear(&initlist); 2077 wlock_release(rtld_bind_lock, lockstate); 2078 return obj; 2079 trace: 2080 trace_loaded_objects(obj); 2081 wlock_release(rtld_bind_lock, lockstate); 2082 exit(0); 2083 } 2084 2085 static void * 2086 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2087 int flags) 2088 { 2089 DoneList donelist; 2090 const Obj_Entry *obj, *defobj; 2091 const Elf_Sym *def, *symp; 2092 unsigned long hash; 2093 int lockstate; 2094 2095 hash = elf_hash(name); 2096 def = NULL; 2097 defobj = NULL; 2098 flags |= SYMLOOK_IN_PLT; 2099 2100 lockstate = rlock_acquire(rtld_bind_lock); 2101 if (handle == NULL || handle == RTLD_NEXT || 2102 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2103 2104 if ((obj = obj_from_addr(retaddr)) == NULL) { 2105 _rtld_error("Cannot determine caller's shared object"); 2106 rlock_release(rtld_bind_lock, lockstate); 2107 return NULL; 2108 } 2109 if (handle == NULL) { /* Just the caller's shared object. */ 2110 def = symlook_obj(name, hash, obj, ve, flags); 2111 defobj = obj; 2112 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2113 handle == RTLD_SELF) { /* ... caller included */ 2114 if (handle == RTLD_NEXT) 2115 obj = obj->next; 2116 for (; obj != NULL; obj = obj->next) { 2117 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2118 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2119 def = symp; 2120 defobj = obj; 2121 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2122 break; 2123 } 2124 } 2125 } 2126 /* 2127 * Search the dynamic linker itself, and possibly resolve the 2128 * symbol from there. This is how the application links to 2129 * dynamic linker services such as dlopen. 2130 */ 2131 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2132 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2133 if (symp != NULL) { 2134 def = symp; 2135 defobj = &obj_rtld; 2136 } 2137 } 2138 } else { 2139 assert(handle == RTLD_DEFAULT); 2140 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2141 } 2142 } else { 2143 if ((obj = dlcheck(handle)) == NULL) { 2144 rlock_release(rtld_bind_lock, lockstate); 2145 return NULL; 2146 } 2147 2148 donelist_init(&donelist); 2149 if (obj->mainprog) { 2150 /* Search main program and all libraries loaded by it. */ 2151 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2152 &donelist); 2153 2154 /* 2155 * We do not distinguish between 'main' object and global scope. 2156 * If symbol is not defined by objects loaded at startup, continue 2157 * search among dynamically loaded objects with RTLD_GLOBAL 2158 * scope. 2159 */ 2160 if (def == NULL) 2161 def = symlook_list(name, hash, &list_global, &defobj, ve, 2162 flags, &donelist); 2163 } else { 2164 Needed_Entry fake; 2165 2166 /* Search the whole DAG rooted at the given object. */ 2167 fake.next = NULL; 2168 fake.obj = (Obj_Entry *)obj; 2169 fake.name = 0; 2170 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2171 &donelist); 2172 } 2173 } 2174 2175 if (def != NULL) { 2176 rlock_release(rtld_bind_lock, lockstate); 2177 2178 /* 2179 * The value required by the caller is derived from the value 2180 * of the symbol. For the ia64 architecture, we need to 2181 * construct a function descriptor which the caller can use to 2182 * call the function with the right 'gp' value. For other 2183 * architectures and for non-functions, the value is simply 2184 * the relocated value of the symbol. 2185 */ 2186 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2187 return make_function_pointer(def, defobj); 2188 else 2189 return defobj->relocbase + def->st_value; 2190 } 2191 2192 _rtld_error("Undefined symbol \"%s\"", name); 2193 rlock_release(rtld_bind_lock, lockstate); 2194 return NULL; 2195 } 2196 2197 void * 2198 dlsym(void *handle, const char *name) 2199 { 2200 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2201 SYMLOOK_DLSYM); 2202 } 2203 2204 dlfunc_t 2205 dlfunc(void *handle, const char *name) 2206 { 2207 union { 2208 void *d; 2209 dlfunc_t f; 2210 } rv; 2211 2212 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2213 SYMLOOK_DLSYM); 2214 return (rv.f); 2215 } 2216 2217 void * 2218 dlvsym(void *handle, const char *name, const char *version) 2219 { 2220 Ver_Entry ventry; 2221 2222 ventry.name = version; 2223 ventry.file = NULL; 2224 ventry.hash = elf_hash(version); 2225 ventry.flags= 0; 2226 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2227 SYMLOOK_DLSYM); 2228 } 2229 2230 int 2231 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2232 { 2233 const Obj_Entry *obj; 2234 int lockstate; 2235 2236 lockstate = rlock_acquire(rtld_bind_lock); 2237 obj = obj_from_addr(addr); 2238 if (obj == NULL) { 2239 _rtld_error("No shared object contains address"); 2240 rlock_release(rtld_bind_lock, lockstate); 2241 return (0); 2242 } 2243 rtld_fill_dl_phdr_info(obj, phdr_info); 2244 rlock_release(rtld_bind_lock, lockstate); 2245 return (1); 2246 } 2247 2248 int 2249 dladdr(const void *addr, Dl_info *info) 2250 { 2251 const Obj_Entry *obj; 2252 const Elf_Sym *def; 2253 void *symbol_addr; 2254 unsigned long symoffset; 2255 int lockstate; 2256 2257 lockstate = rlock_acquire(rtld_bind_lock); 2258 obj = obj_from_addr(addr); 2259 if (obj == NULL) { 2260 _rtld_error("No shared object contains address"); 2261 rlock_release(rtld_bind_lock, lockstate); 2262 return 0; 2263 } 2264 info->dli_fname = obj->path; 2265 info->dli_fbase = obj->mapbase; 2266 info->dli_saddr = (void *)0; 2267 info->dli_sname = NULL; 2268 2269 /* 2270 * Walk the symbol list looking for the symbol whose address is 2271 * closest to the address sent in. 2272 */ 2273 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2274 def = obj->symtab + symoffset; 2275 2276 /* 2277 * For skip the symbol if st_shndx is either SHN_UNDEF or 2278 * SHN_COMMON. 2279 */ 2280 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2281 continue; 2282 2283 /* 2284 * If the symbol is greater than the specified address, or if it 2285 * is further away from addr than the current nearest symbol, 2286 * then reject it. 2287 */ 2288 symbol_addr = obj->relocbase + def->st_value; 2289 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2290 continue; 2291 2292 /* Update our idea of the nearest symbol. */ 2293 info->dli_sname = obj->strtab + def->st_name; 2294 info->dli_saddr = symbol_addr; 2295 2296 /* Exact match? */ 2297 if (info->dli_saddr == addr) 2298 break; 2299 } 2300 rlock_release(rtld_bind_lock, lockstate); 2301 return 1; 2302 } 2303 2304 int 2305 dlinfo(void *handle, int request, void *p) 2306 { 2307 const Obj_Entry *obj; 2308 int error, lockstate; 2309 2310 lockstate = rlock_acquire(rtld_bind_lock); 2311 2312 if (handle == NULL || handle == RTLD_SELF) { 2313 void *retaddr; 2314 2315 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2316 if ((obj = obj_from_addr(retaddr)) == NULL) 2317 _rtld_error("Cannot determine caller's shared object"); 2318 } else 2319 obj = dlcheck(handle); 2320 2321 if (obj == NULL) { 2322 rlock_release(rtld_bind_lock, lockstate); 2323 return (-1); 2324 } 2325 2326 error = 0; 2327 switch (request) { 2328 case RTLD_DI_LINKMAP: 2329 *((struct link_map const **)p) = &obj->linkmap; 2330 break; 2331 case RTLD_DI_ORIGIN: 2332 error = rtld_dirname(obj->path, p); 2333 break; 2334 2335 case RTLD_DI_SERINFOSIZE: 2336 case RTLD_DI_SERINFO: 2337 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2338 break; 2339 2340 default: 2341 _rtld_error("Invalid request %d passed to dlinfo()", request); 2342 error = -1; 2343 } 2344 2345 rlock_release(rtld_bind_lock, lockstate); 2346 2347 return (error); 2348 } 2349 2350 static void 2351 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2352 { 2353 2354 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2355 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2356 STAILQ_FIRST(&obj->names)->name : obj->path; 2357 phdr_info->dlpi_phdr = obj->phdr; 2358 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2359 phdr_info->dlpi_tls_modid = obj->tlsindex; 2360 phdr_info->dlpi_tls_data = obj->tlsinit; 2361 phdr_info->dlpi_adds = obj_loads; 2362 phdr_info->dlpi_subs = obj_loads - obj_count; 2363 } 2364 2365 int 2366 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2367 { 2368 struct dl_phdr_info phdr_info; 2369 const Obj_Entry *obj; 2370 int error, bind_lockstate, phdr_lockstate; 2371 2372 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2373 bind_lockstate = rlock_acquire(rtld_bind_lock); 2374 2375 error = 0; 2376 2377 for (obj = obj_list; obj != NULL; obj = obj->next) { 2378 rtld_fill_dl_phdr_info(obj, &phdr_info); 2379 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2380 break; 2381 2382 } 2383 rlock_release(rtld_bind_lock, bind_lockstate); 2384 wlock_release(rtld_phdr_lock, phdr_lockstate); 2385 2386 return (error); 2387 } 2388 2389 struct fill_search_info_args { 2390 int request; 2391 unsigned int flags; 2392 Dl_serinfo *serinfo; 2393 Dl_serpath *serpath; 2394 char *strspace; 2395 }; 2396 2397 static void * 2398 fill_search_info(const char *dir, size_t dirlen, void *param) 2399 { 2400 struct fill_search_info_args *arg; 2401 2402 arg = param; 2403 2404 if (arg->request == RTLD_DI_SERINFOSIZE) { 2405 arg->serinfo->dls_cnt ++; 2406 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2407 } else { 2408 struct dl_serpath *s_entry; 2409 2410 s_entry = arg->serpath; 2411 s_entry->dls_name = arg->strspace; 2412 s_entry->dls_flags = arg->flags; 2413 2414 strncpy(arg->strspace, dir, dirlen); 2415 arg->strspace[dirlen] = '\0'; 2416 2417 arg->strspace += dirlen + 1; 2418 arg->serpath++; 2419 } 2420 2421 return (NULL); 2422 } 2423 2424 static int 2425 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2426 { 2427 struct dl_serinfo _info; 2428 struct fill_search_info_args args; 2429 2430 args.request = RTLD_DI_SERINFOSIZE; 2431 args.serinfo = &_info; 2432 2433 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2434 _info.dls_cnt = 0; 2435 2436 path_enumerate(ld_library_path, fill_search_info, &args); 2437 path_enumerate(obj->rpath, fill_search_info, &args); 2438 path_enumerate(gethints(), fill_search_info, &args); 2439 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2440 2441 2442 if (request == RTLD_DI_SERINFOSIZE) { 2443 info->dls_size = _info.dls_size; 2444 info->dls_cnt = _info.dls_cnt; 2445 return (0); 2446 } 2447 2448 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2449 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2450 return (-1); 2451 } 2452 2453 args.request = RTLD_DI_SERINFO; 2454 args.serinfo = info; 2455 args.serpath = &info->dls_serpath[0]; 2456 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2457 2458 args.flags = LA_SER_LIBPATH; 2459 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2460 return (-1); 2461 2462 args.flags = LA_SER_RUNPATH; 2463 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2464 return (-1); 2465 2466 args.flags = LA_SER_CONFIG; 2467 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2468 return (-1); 2469 2470 args.flags = LA_SER_DEFAULT; 2471 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2472 return (-1); 2473 return (0); 2474 } 2475 2476 static int 2477 rtld_dirname(const char *path, char *bname) 2478 { 2479 const char *endp; 2480 2481 /* Empty or NULL string gets treated as "." */ 2482 if (path == NULL || *path == '\0') { 2483 bname[0] = '.'; 2484 bname[1] = '\0'; 2485 return (0); 2486 } 2487 2488 /* Strip trailing slashes */ 2489 endp = path + strlen(path) - 1; 2490 while (endp > path && *endp == '/') 2491 endp--; 2492 2493 /* Find the start of the dir */ 2494 while (endp > path && *endp != '/') 2495 endp--; 2496 2497 /* Either the dir is "/" or there are no slashes */ 2498 if (endp == path) { 2499 bname[0] = *endp == '/' ? '/' : '.'; 2500 bname[1] = '\0'; 2501 return (0); 2502 } else { 2503 do { 2504 endp--; 2505 } while (endp > path && *endp == '/'); 2506 } 2507 2508 if (endp - path + 2 > PATH_MAX) 2509 { 2510 _rtld_error("Filename is too long: %s", path); 2511 return(-1); 2512 } 2513 2514 strncpy(bname, path, endp - path + 1); 2515 bname[endp - path + 1] = '\0'; 2516 return (0); 2517 } 2518 2519 static int 2520 rtld_dirname_abs(const char *path, char *base) 2521 { 2522 char base_rel[PATH_MAX]; 2523 2524 if (rtld_dirname(path, base) == -1) 2525 return (-1); 2526 if (base[0] == '/') 2527 return (0); 2528 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2529 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2530 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2531 return (-1); 2532 strcpy(base, base_rel); 2533 return (0); 2534 } 2535 2536 static void 2537 linkmap_add(Obj_Entry *obj) 2538 { 2539 struct link_map *l = &obj->linkmap; 2540 struct link_map *prev; 2541 2542 obj->linkmap.l_name = obj->path; 2543 obj->linkmap.l_addr = obj->mapbase; 2544 obj->linkmap.l_ld = obj->dynamic; 2545 #ifdef __mips__ 2546 /* GDB needs load offset on MIPS to use the symbols */ 2547 obj->linkmap.l_offs = obj->relocbase; 2548 #endif 2549 2550 if (r_debug.r_map == NULL) { 2551 r_debug.r_map = l; 2552 return; 2553 } 2554 2555 /* 2556 * Scan to the end of the list, but not past the entry for the 2557 * dynamic linker, which we want to keep at the very end. 2558 */ 2559 for (prev = r_debug.r_map; 2560 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2561 prev = prev->l_next) 2562 ; 2563 2564 /* Link in the new entry. */ 2565 l->l_prev = prev; 2566 l->l_next = prev->l_next; 2567 if (l->l_next != NULL) 2568 l->l_next->l_prev = l; 2569 prev->l_next = l; 2570 } 2571 2572 static void 2573 linkmap_delete(Obj_Entry *obj) 2574 { 2575 struct link_map *l = &obj->linkmap; 2576 2577 if (l->l_prev == NULL) { 2578 if ((r_debug.r_map = l->l_next) != NULL) 2579 l->l_next->l_prev = NULL; 2580 return; 2581 } 2582 2583 if ((l->l_prev->l_next = l->l_next) != NULL) 2584 l->l_next->l_prev = l->l_prev; 2585 } 2586 2587 /* 2588 * Function for the debugger to set a breakpoint on to gain control. 2589 * 2590 * The two parameters allow the debugger to easily find and determine 2591 * what the runtime loader is doing and to whom it is doing it. 2592 * 2593 * When the loadhook trap is hit (r_debug_state, set at program 2594 * initialization), the arguments can be found on the stack: 2595 * 2596 * +8 struct link_map *m 2597 * +4 struct r_debug *rd 2598 * +0 RetAddr 2599 */ 2600 void 2601 r_debug_state(struct r_debug* rd, struct link_map *m) 2602 { 2603 } 2604 2605 /* 2606 * Get address of the pointer variable in the main program. 2607 */ 2608 static const void ** 2609 get_program_var_addr(const char *name) 2610 { 2611 const Obj_Entry *obj; 2612 unsigned long hash; 2613 2614 hash = elf_hash(name); 2615 for (obj = obj_main; obj != NULL; obj = obj->next) { 2616 const Elf_Sym *def; 2617 2618 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2619 const void **addr; 2620 2621 addr = (const void **)(obj->relocbase + def->st_value); 2622 return addr; 2623 } 2624 } 2625 return NULL; 2626 } 2627 2628 /* 2629 * Set a pointer variable in the main program to the given value. This 2630 * is used to set key variables such as "environ" before any of the 2631 * init functions are called. 2632 */ 2633 static void 2634 set_program_var(const char *name, const void *value) 2635 { 2636 const void **addr; 2637 2638 if ((addr = get_program_var_addr(name)) != NULL) { 2639 dbg("\"%s\": *%p <-- %p", name, addr, value); 2640 *addr = value; 2641 } 2642 } 2643 2644 /* 2645 * Given a symbol name in a referencing object, find the corresponding 2646 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2647 * no definition was found. Returns a pointer to the Obj_Entry of the 2648 * defining object via the reference parameter DEFOBJ_OUT. 2649 */ 2650 static const Elf_Sym * 2651 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2652 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2653 { 2654 DoneList donelist; 2655 const Elf_Sym *def; 2656 const Elf_Sym *symp; 2657 const Obj_Entry *obj; 2658 const Obj_Entry *defobj; 2659 const Objlist_Entry *elm; 2660 def = NULL; 2661 defobj = NULL; 2662 donelist_init(&donelist); 2663 2664 /* Look first in the referencing object if linked symbolically. */ 2665 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2666 symp = symlook_obj(name, hash, refobj, ventry, flags); 2667 if (symp != NULL) { 2668 def = symp; 2669 defobj = refobj; 2670 } 2671 } 2672 2673 /* Search all objects loaded at program start up. */ 2674 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2675 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2676 &donelist); 2677 if (symp != NULL && 2678 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2679 def = symp; 2680 defobj = obj; 2681 } 2682 } 2683 2684 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2685 STAILQ_FOREACH(elm, &list_global, link) { 2686 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2687 break; 2688 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2689 flags, &donelist); 2690 if (symp != NULL && 2691 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2692 def = symp; 2693 defobj = obj; 2694 } 2695 } 2696 2697 /* Search all dlopened DAGs containing the referencing object. */ 2698 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2699 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2700 break; 2701 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2702 flags, &donelist); 2703 if (symp != NULL && 2704 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2705 def = symp; 2706 defobj = obj; 2707 } 2708 } 2709 2710 /* 2711 * Search the dynamic linker itself, and possibly resolve the 2712 * symbol from there. This is how the application links to 2713 * dynamic linker services such as dlopen. 2714 */ 2715 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2716 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2717 if (symp != NULL) { 2718 def = symp; 2719 defobj = &obj_rtld; 2720 } 2721 } 2722 2723 if (def != NULL) 2724 *defobj_out = defobj; 2725 return def; 2726 } 2727 2728 static const Elf_Sym * 2729 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2730 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2731 DoneList *dlp) 2732 { 2733 const Elf_Sym *symp; 2734 const Elf_Sym *def; 2735 const Obj_Entry *defobj; 2736 const Objlist_Entry *elm; 2737 2738 def = NULL; 2739 defobj = NULL; 2740 STAILQ_FOREACH(elm, objlist, link) { 2741 if (donelist_check(dlp, elm->obj)) 2742 continue; 2743 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2744 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2745 def = symp; 2746 defobj = elm->obj; 2747 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2748 break; 2749 } 2750 } 2751 } 2752 if (def != NULL) 2753 *defobj_out = defobj; 2754 return def; 2755 } 2756 2757 /* 2758 * Search the symbol table of a shared object and all objects needed 2759 * by it for a symbol of the given name. Search order is 2760 * breadth-first. Returns a pointer to the symbol, or NULL if no 2761 * definition was found. 2762 */ 2763 static const Elf_Sym * 2764 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2765 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2766 DoneList *dlp) 2767 { 2768 const Elf_Sym *def, *def_w; 2769 const Needed_Entry *n; 2770 const Obj_Entry *obj, *defobj, *defobj1; 2771 2772 def = def_w = NULL; 2773 defobj = NULL; 2774 for (n = needed; n != NULL; n = n->next) { 2775 if ((obj = n->obj) == NULL || 2776 donelist_check(dlp, obj) || 2777 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2778 continue; 2779 defobj = obj; 2780 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2781 *defobj_out = defobj; 2782 return (def); 2783 } 2784 } 2785 /* 2786 * There we come when either symbol definition is not found in 2787 * directly needed objects, or found symbol is weak. 2788 */ 2789 for (n = needed; n != NULL; n = n->next) { 2790 if ((obj = n->obj) == NULL) 2791 continue; 2792 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2793 ventry, flags, dlp); 2794 if (def_w == NULL) 2795 continue; 2796 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2797 def = def_w; 2798 defobj = defobj1; 2799 } 2800 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2801 break; 2802 } 2803 if (def != NULL) 2804 *defobj_out = defobj; 2805 return (def); 2806 } 2807 2808 /* 2809 * Search the symbol table of a single shared object for a symbol of 2810 * the given name and version, if requested. Returns a pointer to the 2811 * symbol, or NULL if no definition was found. 2812 * 2813 * The symbol's hash value is passed in for efficiency reasons; that 2814 * eliminates many recomputations of the hash value. 2815 */ 2816 const Elf_Sym * 2817 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2818 const Ver_Entry *ventry, int flags) 2819 { 2820 unsigned long symnum; 2821 const Elf_Sym *vsymp; 2822 Elf_Versym verndx; 2823 int vcount; 2824 2825 if (obj->buckets == NULL) 2826 return NULL; 2827 2828 vsymp = NULL; 2829 vcount = 0; 2830 symnum = obj->buckets[hash % obj->nbuckets]; 2831 2832 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2833 const Elf_Sym *symp; 2834 const char *strp; 2835 2836 if (symnum >= obj->nchains) 2837 return NULL; /* Bad object */ 2838 2839 symp = obj->symtab + symnum; 2840 strp = obj->strtab + symp->st_name; 2841 2842 switch (ELF_ST_TYPE(symp->st_info)) { 2843 case STT_FUNC: 2844 case STT_NOTYPE: 2845 case STT_OBJECT: 2846 if (symp->st_value == 0) 2847 continue; 2848 /* fallthrough */ 2849 case STT_TLS: 2850 if (symp->st_shndx != SHN_UNDEF) 2851 break; 2852 #ifndef __mips__ 2853 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2854 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2855 break; 2856 /* fallthrough */ 2857 #endif 2858 default: 2859 continue; 2860 } 2861 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2862 continue; 2863 2864 if (ventry == NULL) { 2865 if (obj->versyms != NULL) { 2866 verndx = VER_NDX(obj->versyms[symnum]); 2867 if (verndx > obj->vernum) { 2868 _rtld_error("%s: symbol %s references wrong version %d", 2869 obj->path, obj->strtab + symnum, verndx); 2870 continue; 2871 } 2872 /* 2873 * If we are not called from dlsym (i.e. this is a normal 2874 * relocation from unversioned binary, accept the symbol 2875 * immediately if it happens to have first version after 2876 * this shared object became versioned. Otherwise, if 2877 * symbol is versioned and not hidden, remember it. If it 2878 * is the only symbol with this name exported by the 2879 * shared object, it will be returned as a match at the 2880 * end of the function. If symbol is global (verndx < 2) 2881 * accept it unconditionally. 2882 */ 2883 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2884 return symp; 2885 else if (verndx >= VER_NDX_GIVEN) { 2886 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2887 if (vsymp == NULL) 2888 vsymp = symp; 2889 vcount ++; 2890 } 2891 continue; 2892 } 2893 } 2894 return symp; 2895 } else { 2896 if (obj->versyms == NULL) { 2897 if (object_match_name(obj, ventry->name)) { 2898 _rtld_error("%s: object %s should provide version %s for " 2899 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2900 obj->strtab + symnum); 2901 continue; 2902 } 2903 } else { 2904 verndx = VER_NDX(obj->versyms[symnum]); 2905 if (verndx > obj->vernum) { 2906 _rtld_error("%s: symbol %s references wrong version %d", 2907 obj->path, obj->strtab + symnum, verndx); 2908 continue; 2909 } 2910 if (obj->vertab[verndx].hash != ventry->hash || 2911 strcmp(obj->vertab[verndx].name, ventry->name)) { 2912 /* 2913 * Version does not match. Look if this is a global symbol 2914 * and if it is not hidden. If global symbol (verndx < 2) 2915 * is available, use it. Do not return symbol if we are 2916 * called by dlvsym, because dlvsym looks for a specific 2917 * version and default one is not what dlvsym wants. 2918 */ 2919 if ((flags & SYMLOOK_DLSYM) || 2920 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2921 (verndx >= VER_NDX_GIVEN)) 2922 continue; 2923 } 2924 } 2925 return symp; 2926 } 2927 } 2928 return (vcount == 1) ? vsymp : NULL; 2929 } 2930 2931 static void 2932 trace_loaded_objects(Obj_Entry *obj) 2933 { 2934 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2935 int c; 2936 2937 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2938 main_local = ""; 2939 2940 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2941 fmt1 = "\t%o => %p (%x)\n"; 2942 2943 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2944 fmt2 = "\t%o (%x)\n"; 2945 2946 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2947 2948 for (; obj; obj = obj->next) { 2949 Needed_Entry *needed; 2950 char *name, *path; 2951 bool is_lib; 2952 2953 if (list_containers && obj->needed != NULL) 2954 printf("%s:\n", obj->path); 2955 for (needed = obj->needed; needed; needed = needed->next) { 2956 if (needed->obj != NULL) { 2957 if (needed->obj->traced && !list_containers) 2958 continue; 2959 needed->obj->traced = true; 2960 path = needed->obj->path; 2961 } else 2962 path = "not found"; 2963 2964 name = (char *)obj->strtab + needed->name; 2965 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2966 2967 fmt = is_lib ? fmt1 : fmt2; 2968 while ((c = *fmt++) != '\0') { 2969 switch (c) { 2970 default: 2971 putchar(c); 2972 continue; 2973 case '\\': 2974 switch (c = *fmt) { 2975 case '\0': 2976 continue; 2977 case 'n': 2978 putchar('\n'); 2979 break; 2980 case 't': 2981 putchar('\t'); 2982 break; 2983 } 2984 break; 2985 case '%': 2986 switch (c = *fmt) { 2987 case '\0': 2988 continue; 2989 case '%': 2990 default: 2991 putchar(c); 2992 break; 2993 case 'A': 2994 printf("%s", main_local); 2995 break; 2996 case 'a': 2997 printf("%s", obj_main->path); 2998 break; 2999 case 'o': 3000 printf("%s", name); 3001 break; 3002 #if 0 3003 case 'm': 3004 printf("%d", sodp->sod_major); 3005 break; 3006 case 'n': 3007 printf("%d", sodp->sod_minor); 3008 break; 3009 #endif 3010 case 'p': 3011 printf("%s", path); 3012 break; 3013 case 'x': 3014 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3015 break; 3016 } 3017 break; 3018 } 3019 ++fmt; 3020 } 3021 } 3022 } 3023 } 3024 3025 /* 3026 * Unload a dlopened object and its dependencies from memory and from 3027 * our data structures. It is assumed that the DAG rooted in the 3028 * object has already been unreferenced, and that the object has a 3029 * reference count of 0. 3030 */ 3031 static void 3032 unload_object(Obj_Entry *root) 3033 { 3034 Obj_Entry *obj; 3035 Obj_Entry **linkp; 3036 3037 assert(root->refcount == 0); 3038 3039 /* 3040 * Pass over the DAG removing unreferenced objects from 3041 * appropriate lists. 3042 */ 3043 unlink_object(root); 3044 3045 /* Unmap all objects that are no longer referenced. */ 3046 linkp = &obj_list->next; 3047 while ((obj = *linkp) != NULL) { 3048 if (obj->refcount == 0) { 3049 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3050 obj->path); 3051 dbg("unloading \"%s\"", obj->path); 3052 munmap(obj->mapbase, obj->mapsize); 3053 linkmap_delete(obj); 3054 *linkp = obj->next; 3055 obj_count--; 3056 obj_free(obj); 3057 } else 3058 linkp = &obj->next; 3059 } 3060 obj_tail = linkp; 3061 } 3062 3063 static void 3064 unlink_object(Obj_Entry *root) 3065 { 3066 Objlist_Entry *elm; 3067 3068 if (root->refcount == 0) { 3069 /* Remove the object from the RTLD_GLOBAL list. */ 3070 objlist_remove(&list_global, root); 3071 3072 /* Remove the object from all objects' DAG lists. */ 3073 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3074 objlist_remove(&elm->obj->dldags, root); 3075 if (elm->obj != root) 3076 unlink_object(elm->obj); 3077 } 3078 } 3079 } 3080 3081 static void 3082 ref_dag(Obj_Entry *root) 3083 { 3084 Objlist_Entry *elm; 3085 3086 assert(root->dag_inited); 3087 STAILQ_FOREACH(elm, &root->dagmembers, link) 3088 elm->obj->refcount++; 3089 } 3090 3091 static void 3092 unref_dag(Obj_Entry *root) 3093 { 3094 Objlist_Entry *elm; 3095 3096 assert(root->dag_inited); 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