1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/uio.h> 44 #include <sys/ktrace.h> 45 46 #include <dlfcn.h> 47 #include <err.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <stdarg.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 56 #include "debug.h" 57 #include "rtld.h" 58 #include "libmap.h" 59 #include "rtld_tls.h" 60 61 #ifndef COMPAT_32BIT 62 #define PATH_RTLD "/libexec/ld-elf.so.1" 63 #else 64 #define PATH_RTLD "/libexec/ld-elf32.so.1" 65 #endif 66 67 /* Types. */ 68 typedef void (*func_ptr_type)(); 69 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 70 71 /* 72 * This structure provides a reentrant way to keep a list of objects and 73 * check which ones have already been processed in some way. 74 */ 75 typedef struct Struct_DoneList { 76 const Obj_Entry **objs; /* Array of object pointers */ 77 unsigned int num_alloc; /* Allocated size of the array */ 78 unsigned int num_used; /* Number of array slots used */ 79 } DoneList; 80 81 /* 82 * Function declarations. 83 */ 84 static const char *basename(const char *); 85 static void die(void) __dead2; 86 static void digest_dynamic(Obj_Entry *, int); 87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 88 static Obj_Entry *dlcheck(void *); 89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *); 90 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 91 static bool donelist_check(DoneList *, const Obj_Entry *); 92 static void errmsg_restore(char *); 93 static char *errmsg_save(void); 94 static void *fill_search_info(const char *, size_t, void *); 95 static char *find_library(const char *, const Obj_Entry *); 96 static const char *gethints(void); 97 static void init_dag(Obj_Entry *); 98 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 99 static void init_rtld(caddr_t); 100 static void initlist_add_neededs(Needed_Entry *, Objlist *); 101 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 102 static bool is_exported(const Elf_Sym *); 103 static void linkmap_add(Obj_Entry *); 104 static void linkmap_delete(Obj_Entry *); 105 static int load_needed_objects(Obj_Entry *); 106 static int load_preload_objects(void); 107 static Obj_Entry *load_object(const char *, const Obj_Entry *); 108 static Obj_Entry *obj_from_addr(const void *); 109 static void objlist_call_fini(Objlist *, int *lockstate); 110 static void objlist_call_init(Objlist *, int *lockstate); 111 static void objlist_clear(Objlist *); 112 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 113 static void objlist_init(Objlist *); 114 static void objlist_push_head(Objlist *, Obj_Entry *); 115 static void objlist_push_tail(Objlist *, Obj_Entry *); 116 static void objlist_remove(Objlist *, Obj_Entry *); 117 static void objlist_remove_unref(Objlist *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 120 static int rtld_dirname(const char *, char *); 121 static void rtld_exit(void); 122 static char *search_library_path(const char *, const char *); 123 static const void **get_program_var_addr(const char *); 124 static void set_program_var(const char *, const void *); 125 static const Elf_Sym *symlook_default(const char *, unsigned long, 126 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 127 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 128 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 129 static const Elf_Sym *symlook_needed(const char *, unsigned long, 130 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 131 int, DoneList *); 132 static void trace_loaded_objects(Obj_Entry *); 133 static void unlink_object(Obj_Entry *); 134 static void unload_object(Obj_Entry *); 135 static void unref_dag(Obj_Entry *); 136 static void ref_dag(Obj_Entry *); 137 static int rtld_verify_versions(const Objlist *); 138 static int rtld_verify_object_versions(Obj_Entry *); 139 static void object_add_name(Obj_Entry *, const char *); 140 static int object_match_name(const Obj_Entry *, const char *); 141 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 142 143 void r_debug_state(struct r_debug *, struct link_map *); 144 145 /* 146 * Data declarations. 147 */ 148 static char *error_message; /* Message for dlerror(), or NULL */ 149 struct r_debug r_debug; /* for GDB; */ 150 static bool libmap_disable; /* Disable libmap */ 151 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 152 static bool trust; /* False for setuid and setgid programs */ 153 static bool dangerous_ld_env; /* True if environment variables have been 154 used to affect the libraries loaded */ 155 static char *ld_bind_now; /* Environment variable for immediate binding */ 156 static char *ld_debug; /* Environment variable for debugging */ 157 static char *ld_library_path; /* Environment variable for search path */ 158 static char *ld_preload; /* Environment variable for libraries to 159 load first */ 160 static char *ld_tracing; /* Called from ldd to print libs */ 161 static char *ld_utrace; /* Use utrace() to log events. */ 162 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 163 static Obj_Entry **obj_tail; /* Link field of last object in list */ 164 static Obj_Entry *obj_main; /* The main program shared object */ 165 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 166 static unsigned int obj_count; /* Number of objects in obj_list */ 167 static unsigned int obj_loads; /* Number of objects in obj_list */ 168 169 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 170 STAILQ_HEAD_INITIALIZER(list_global); 171 static Objlist list_main = /* Objects loaded at program startup */ 172 STAILQ_HEAD_INITIALIZER(list_main); 173 static Objlist list_fini = /* Objects needing fini() calls */ 174 STAILQ_HEAD_INITIALIZER(list_fini); 175 176 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 177 178 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 179 180 extern Elf_Dyn _DYNAMIC; 181 #pragma weak _DYNAMIC 182 #ifndef RTLD_IS_DYNAMIC 183 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 184 #endif 185 186 /* 187 * These are the functions the dynamic linker exports to application 188 * programs. They are the only symbols the dynamic linker is willing 189 * to export from itself. 190 */ 191 static func_ptr_type exports[] = { 192 (func_ptr_type) &_rtld_error, 193 (func_ptr_type) &dlclose, 194 (func_ptr_type) &dlerror, 195 (func_ptr_type) &dlopen, 196 (func_ptr_type) &dlsym, 197 (func_ptr_type) &dlvsym, 198 (func_ptr_type) &dladdr, 199 (func_ptr_type) &dllockinit, 200 (func_ptr_type) &dlinfo, 201 (func_ptr_type) &_rtld_thread_init, 202 #ifdef __i386__ 203 (func_ptr_type) &___tls_get_addr, 204 #endif 205 (func_ptr_type) &__tls_get_addr, 206 (func_ptr_type) &_rtld_allocate_tls, 207 (func_ptr_type) &_rtld_free_tls, 208 (func_ptr_type) &dl_iterate_phdr, 209 (func_ptr_type) &_rtld_atfork_pre, 210 (func_ptr_type) &_rtld_atfork_post, 211 NULL 212 }; 213 214 /* 215 * Global declarations normally provided by crt1. The dynamic linker is 216 * not built with crt1, so we have to provide them ourselves. 217 */ 218 char *__progname; 219 char **environ; 220 221 /* 222 * Globals to control TLS allocation. 223 */ 224 size_t tls_last_offset; /* Static TLS offset of last module */ 225 size_t tls_last_size; /* Static TLS size of last module */ 226 size_t tls_static_space; /* Static TLS space allocated */ 227 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 228 int tls_max_index = 1; /* Largest module index allocated */ 229 230 /* 231 * Fill in a DoneList with an allocation large enough to hold all of 232 * the currently-loaded objects. Keep this as a macro since it calls 233 * alloca and we want that to occur within the scope of the caller. 234 */ 235 #define donelist_init(dlp) \ 236 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 237 assert((dlp)->objs != NULL), \ 238 (dlp)->num_alloc = obj_count, \ 239 (dlp)->num_used = 0) 240 241 #define UTRACE_DLOPEN_START 1 242 #define UTRACE_DLOPEN_STOP 2 243 #define UTRACE_DLCLOSE_START 3 244 #define UTRACE_DLCLOSE_STOP 4 245 #define UTRACE_LOAD_OBJECT 5 246 #define UTRACE_UNLOAD_OBJECT 6 247 #define UTRACE_ADD_RUNDEP 7 248 #define UTRACE_PRELOAD_FINISHED 8 249 #define UTRACE_INIT_CALL 9 250 #define UTRACE_FINI_CALL 10 251 252 struct utrace_rtld { 253 char sig[4]; /* 'RTLD' */ 254 int event; 255 void *handle; 256 void *mapbase; /* Used for 'parent' and 'init/fini' */ 257 size_t mapsize; 258 int refcnt; /* Used for 'mode' */ 259 char name[MAXPATHLEN]; 260 }; 261 262 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 263 if (ld_utrace != NULL) \ 264 ld_utrace_log(e, h, mb, ms, r, n); \ 265 } while (0) 266 267 static void 268 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 269 int refcnt, const char *name) 270 { 271 struct utrace_rtld ut; 272 273 ut.sig[0] = 'R'; 274 ut.sig[1] = 'T'; 275 ut.sig[2] = 'L'; 276 ut.sig[3] = 'D'; 277 ut.event = event; 278 ut.handle = handle; 279 ut.mapbase = mapbase; 280 ut.mapsize = mapsize; 281 ut.refcnt = refcnt; 282 bzero(ut.name, sizeof(ut.name)); 283 if (name) 284 strlcpy(ut.name, name, sizeof(ut.name)); 285 utrace(&ut, sizeof(ut)); 286 } 287 288 /* 289 * Main entry point for dynamic linking. The first argument is the 290 * stack pointer. The stack is expected to be laid out as described 291 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 292 * Specifically, the stack pointer points to a word containing 293 * ARGC. Following that in the stack is a null-terminated sequence 294 * of pointers to argument strings. Then comes a null-terminated 295 * sequence of pointers to environment strings. Finally, there is a 296 * sequence of "auxiliary vector" entries. 297 * 298 * The second argument points to a place to store the dynamic linker's 299 * exit procedure pointer and the third to a place to store the main 300 * program's object. 301 * 302 * The return value is the main program's entry point. 303 */ 304 func_ptr_type 305 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 306 { 307 Elf_Auxinfo *aux_info[AT_COUNT]; 308 int i; 309 int argc; 310 char **argv; 311 char **env; 312 Elf_Auxinfo *aux; 313 Elf_Auxinfo *auxp; 314 const char *argv0; 315 Objlist_Entry *entry; 316 Obj_Entry *obj; 317 Obj_Entry **preload_tail; 318 Objlist initlist; 319 int lockstate; 320 321 /* 322 * On entry, the dynamic linker itself has not been relocated yet. 323 * Be very careful not to reference any global data until after 324 * init_rtld has returned. It is OK to reference file-scope statics 325 * and string constants, and to call static and global functions. 326 */ 327 328 /* Find the auxiliary vector on the stack. */ 329 argc = *sp++; 330 argv = (char **) sp; 331 sp += argc + 1; /* Skip over arguments and NULL terminator */ 332 env = (char **) sp; 333 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 334 ; 335 aux = (Elf_Auxinfo *) sp; 336 337 /* Digest the auxiliary vector. */ 338 for (i = 0; i < AT_COUNT; i++) 339 aux_info[i] = NULL; 340 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 341 if (auxp->a_type < AT_COUNT) 342 aux_info[auxp->a_type] = auxp; 343 } 344 345 /* Initialize and relocate ourselves. */ 346 assert(aux_info[AT_BASE] != NULL); 347 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 348 349 __progname = obj_rtld.path; 350 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 351 environ = env; 352 353 trust = !issetugid(); 354 355 ld_bind_now = getenv(LD_ "BIND_NOW"); 356 /* 357 * If the process is tainted, then we un-set the dangerous environment 358 * variables. The process will be marked as tainted until setuid(2) 359 * is called. If any child process calls setuid(2) we do not want any 360 * future processes to honor the potentially un-safe variables. 361 */ 362 if (!trust) { 363 unsetenv(LD_ "PRELOAD"); 364 unsetenv(LD_ "LIBMAP"); 365 unsetenv(LD_ "LIBRARY_PATH"); 366 unsetenv(LD_ "LIBMAP_DISABLE"); 367 unsetenv(LD_ "DEBUG"); 368 } 369 ld_debug = getenv(LD_ "DEBUG"); 370 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 371 libmap_override = getenv(LD_ "LIBMAP"); 372 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 373 ld_preload = getenv(LD_ "PRELOAD"); 374 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 375 (ld_library_path != NULL) || (ld_preload != NULL); 376 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 377 ld_utrace = getenv(LD_ "UTRACE"); 378 379 if (ld_debug != NULL && *ld_debug != '\0') 380 debug = 1; 381 dbg("%s is initialized, base address = %p", __progname, 382 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 383 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 384 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 385 386 /* 387 * Load the main program, or process its program header if it is 388 * already loaded. 389 */ 390 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 391 int fd = aux_info[AT_EXECFD]->a_un.a_val; 392 dbg("loading main program"); 393 obj_main = map_object(fd, argv0, NULL); 394 close(fd); 395 if (obj_main == NULL) 396 die(); 397 } else { /* Main program already loaded. */ 398 const Elf_Phdr *phdr; 399 int phnum; 400 caddr_t entry; 401 402 dbg("processing main program's program header"); 403 assert(aux_info[AT_PHDR] != NULL); 404 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 405 assert(aux_info[AT_PHNUM] != NULL); 406 phnum = aux_info[AT_PHNUM]->a_un.a_val; 407 assert(aux_info[AT_PHENT] != NULL); 408 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 409 assert(aux_info[AT_ENTRY] != NULL); 410 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 411 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 412 die(); 413 } 414 415 obj_main->path = xstrdup(argv0); 416 obj_main->mainprog = true; 417 418 /* 419 * Get the actual dynamic linker pathname from the executable if 420 * possible. (It should always be possible.) That ensures that 421 * gdb will find the right dynamic linker even if a non-standard 422 * one is being used. 423 */ 424 if (obj_main->interp != NULL && 425 strcmp(obj_main->interp, obj_rtld.path) != 0) { 426 free(obj_rtld.path); 427 obj_rtld.path = xstrdup(obj_main->interp); 428 __progname = obj_rtld.path; 429 } 430 431 digest_dynamic(obj_main, 0); 432 433 linkmap_add(obj_main); 434 linkmap_add(&obj_rtld); 435 436 /* Link the main program into the list of objects. */ 437 *obj_tail = obj_main; 438 obj_tail = &obj_main->next; 439 obj_count++; 440 obj_loads++; 441 /* Make sure we don't call the main program's init and fini functions. */ 442 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 443 444 /* Initialize a fake symbol for resolving undefined weak references. */ 445 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 446 sym_zero.st_shndx = SHN_UNDEF; 447 448 if (!libmap_disable) 449 libmap_disable = (bool)lm_init(libmap_override); 450 451 dbg("loading LD_PRELOAD libraries"); 452 if (load_preload_objects() == -1) 453 die(); 454 preload_tail = obj_tail; 455 456 dbg("loading needed objects"); 457 if (load_needed_objects(obj_main) == -1) 458 die(); 459 460 /* Make a list of all objects loaded at startup. */ 461 for (obj = obj_list; obj != NULL; obj = obj->next) { 462 objlist_push_tail(&list_main, obj); 463 obj->refcount++; 464 } 465 466 dbg("checking for required versions"); 467 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 468 die(); 469 470 if (ld_tracing) { /* We're done */ 471 trace_loaded_objects(obj_main); 472 exit(0); 473 } 474 475 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 476 dump_relocations(obj_main); 477 exit (0); 478 } 479 480 /* setup TLS for main thread */ 481 dbg("initializing initial thread local storage"); 482 STAILQ_FOREACH(entry, &list_main, link) { 483 /* 484 * Allocate all the initial objects out of the static TLS 485 * block even if they didn't ask for it. 486 */ 487 allocate_tls_offset(entry->obj); 488 } 489 allocate_initial_tls(obj_list); 490 491 if (relocate_objects(obj_main, 492 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 493 die(); 494 495 dbg("doing copy relocations"); 496 if (do_copy_relocations(obj_main) == -1) 497 die(); 498 499 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 500 dump_relocations(obj_main); 501 exit (0); 502 } 503 504 dbg("initializing key program variables"); 505 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 506 set_program_var("environ", env); 507 508 dbg("initializing thread locks"); 509 lockdflt_init(); 510 511 /* Make a list of init functions to call. */ 512 objlist_init(&initlist); 513 initlist_add_objects(obj_list, preload_tail, &initlist); 514 515 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 516 517 lockstate = wlock_acquire(rtld_bind_lock); 518 objlist_call_init(&initlist, &lockstate); 519 objlist_clear(&initlist); 520 wlock_release(rtld_bind_lock, lockstate); 521 522 dbg("transferring control to program entry point = %p", obj_main->entry); 523 524 /* Return the exit procedure and the program entry point. */ 525 *exit_proc = rtld_exit; 526 *objp = obj_main; 527 return (func_ptr_type) obj_main->entry; 528 } 529 530 Elf_Addr 531 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 532 { 533 const Elf_Rel *rel; 534 const Elf_Sym *def; 535 const Obj_Entry *defobj; 536 Elf_Addr *where; 537 Elf_Addr target; 538 int lockstate; 539 540 lockstate = rlock_acquire(rtld_bind_lock); 541 if (obj->pltrel) 542 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 543 else 544 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 545 546 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 547 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 548 if (def == NULL) 549 die(); 550 551 target = (Elf_Addr)(defobj->relocbase + def->st_value); 552 553 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 554 defobj->strtab + def->st_name, basename(obj->path), 555 (void *)target, basename(defobj->path)); 556 557 /* 558 * Write the new contents for the jmpslot. Note that depending on 559 * architecture, the value which we need to return back to the 560 * lazy binding trampoline may or may not be the target 561 * address. The value returned from reloc_jmpslot() is the value 562 * that the trampoline needs. 563 */ 564 target = reloc_jmpslot(where, target, defobj, obj, rel); 565 rlock_release(rtld_bind_lock, lockstate); 566 return target; 567 } 568 569 /* 570 * Error reporting function. Use it like printf. If formats the message 571 * into a buffer, and sets things up so that the next call to dlerror() 572 * will return the message. 573 */ 574 void 575 _rtld_error(const char *fmt, ...) 576 { 577 static char buf[512]; 578 va_list ap; 579 580 va_start(ap, fmt); 581 vsnprintf(buf, sizeof buf, fmt, ap); 582 error_message = buf; 583 va_end(ap); 584 } 585 586 /* 587 * Return a dynamically-allocated copy of the current error message, if any. 588 */ 589 static char * 590 errmsg_save(void) 591 { 592 return error_message == NULL ? NULL : xstrdup(error_message); 593 } 594 595 /* 596 * Restore the current error message from a copy which was previously saved 597 * by errmsg_save(). The copy is freed. 598 */ 599 static void 600 errmsg_restore(char *saved_msg) 601 { 602 if (saved_msg == NULL) 603 error_message = NULL; 604 else { 605 _rtld_error("%s", saved_msg); 606 free(saved_msg); 607 } 608 } 609 610 static const char * 611 basename(const char *name) 612 { 613 const char *p = strrchr(name, '/'); 614 return p != NULL ? p + 1 : name; 615 } 616 617 static void 618 die(void) 619 { 620 const char *msg = dlerror(); 621 622 if (msg == NULL) 623 msg = "Fatal error"; 624 errx(1, "%s", msg); 625 } 626 627 /* 628 * Process a shared object's DYNAMIC section, and save the important 629 * information in its Obj_Entry structure. 630 */ 631 static void 632 digest_dynamic(Obj_Entry *obj, int early) 633 { 634 const Elf_Dyn *dynp; 635 Needed_Entry **needed_tail = &obj->needed; 636 const Elf_Dyn *dyn_rpath = NULL; 637 const Elf_Dyn *dyn_soname = NULL; 638 int plttype = DT_REL; 639 640 obj->bind_now = false; 641 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 642 switch (dynp->d_tag) { 643 644 case DT_REL: 645 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 646 break; 647 648 case DT_RELSZ: 649 obj->relsize = dynp->d_un.d_val; 650 break; 651 652 case DT_RELENT: 653 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 654 break; 655 656 case DT_JMPREL: 657 obj->pltrel = (const Elf_Rel *) 658 (obj->relocbase + dynp->d_un.d_ptr); 659 break; 660 661 case DT_PLTRELSZ: 662 obj->pltrelsize = dynp->d_un.d_val; 663 break; 664 665 case DT_RELA: 666 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 667 break; 668 669 case DT_RELASZ: 670 obj->relasize = dynp->d_un.d_val; 671 break; 672 673 case DT_RELAENT: 674 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 675 break; 676 677 case DT_PLTREL: 678 plttype = dynp->d_un.d_val; 679 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 680 break; 681 682 case DT_SYMTAB: 683 obj->symtab = (const Elf_Sym *) 684 (obj->relocbase + dynp->d_un.d_ptr); 685 break; 686 687 case DT_SYMENT: 688 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 689 break; 690 691 case DT_STRTAB: 692 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 693 break; 694 695 case DT_STRSZ: 696 obj->strsize = dynp->d_un.d_val; 697 break; 698 699 case DT_VERNEED: 700 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 701 dynp->d_un.d_val); 702 break; 703 704 case DT_VERNEEDNUM: 705 obj->verneednum = dynp->d_un.d_val; 706 break; 707 708 case DT_VERDEF: 709 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 710 dynp->d_un.d_val); 711 break; 712 713 case DT_VERDEFNUM: 714 obj->verdefnum = dynp->d_un.d_val; 715 break; 716 717 case DT_VERSYM: 718 obj->versyms = (const Elf_Versym *)(obj->relocbase + 719 dynp->d_un.d_val); 720 break; 721 722 case DT_HASH: 723 { 724 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 725 (obj->relocbase + dynp->d_un.d_ptr); 726 obj->nbuckets = hashtab[0]; 727 obj->nchains = hashtab[1]; 728 obj->buckets = hashtab + 2; 729 obj->chains = obj->buckets + obj->nbuckets; 730 } 731 break; 732 733 case DT_NEEDED: 734 if (!obj->rtld) { 735 Needed_Entry *nep = NEW(Needed_Entry); 736 nep->name = dynp->d_un.d_val; 737 nep->obj = NULL; 738 nep->next = NULL; 739 740 *needed_tail = nep; 741 needed_tail = &nep->next; 742 } 743 break; 744 745 case DT_PLTGOT: 746 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 747 break; 748 749 case DT_TEXTREL: 750 obj->textrel = true; 751 break; 752 753 case DT_SYMBOLIC: 754 obj->symbolic = true; 755 break; 756 757 case DT_RPATH: 758 case DT_RUNPATH: /* XXX: process separately */ 759 /* 760 * We have to wait until later to process this, because we 761 * might not have gotten the address of the string table yet. 762 */ 763 dyn_rpath = dynp; 764 break; 765 766 case DT_SONAME: 767 dyn_soname = dynp; 768 break; 769 770 case DT_INIT: 771 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 772 break; 773 774 case DT_FINI: 775 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 776 break; 777 778 /* 779 * Don't process DT_DEBUG on MIPS as the dynamic section 780 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 781 */ 782 783 #ifndef __mips__ 784 case DT_DEBUG: 785 /* XXX - not implemented yet */ 786 if (!early) 787 dbg("Filling in DT_DEBUG entry"); 788 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 789 break; 790 #endif 791 792 case DT_FLAGS: 793 if (dynp->d_un.d_val & DF_ORIGIN) { 794 obj->origin_path = xmalloc(PATH_MAX); 795 if (rtld_dirname(obj->path, obj->origin_path) == -1) 796 die(); 797 } 798 if (dynp->d_un.d_val & DF_SYMBOLIC) 799 obj->symbolic = true; 800 if (dynp->d_un.d_val & DF_TEXTREL) 801 obj->textrel = true; 802 if (dynp->d_un.d_val & DF_BIND_NOW) 803 obj->bind_now = true; 804 if (dynp->d_un.d_val & DF_STATIC_TLS) 805 ; 806 break; 807 #ifdef __mips__ 808 case DT_MIPS_LOCAL_GOTNO: 809 obj->local_gotno = dynp->d_un.d_val; 810 break; 811 812 case DT_MIPS_SYMTABNO: 813 obj->symtabno = dynp->d_un.d_val; 814 break; 815 816 case DT_MIPS_GOTSYM: 817 obj->gotsym = dynp->d_un.d_val; 818 break; 819 820 case DT_MIPS_RLD_MAP: 821 #ifdef notyet 822 if (!early) 823 dbg("Filling in DT_DEBUG entry"); 824 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 825 #endif 826 break; 827 #endif 828 829 default: 830 if (!early) { 831 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 832 (long)dynp->d_tag); 833 } 834 break; 835 } 836 } 837 838 obj->traced = false; 839 840 if (plttype == DT_RELA) { 841 obj->pltrela = (const Elf_Rela *) obj->pltrel; 842 obj->pltrel = NULL; 843 obj->pltrelasize = obj->pltrelsize; 844 obj->pltrelsize = 0; 845 } 846 847 if (dyn_rpath != NULL) 848 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val; 849 850 if (dyn_soname != NULL) 851 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 852 } 853 854 /* 855 * Process a shared object's program header. This is used only for the 856 * main program, when the kernel has already loaded the main program 857 * into memory before calling the dynamic linker. It creates and 858 * returns an Obj_Entry structure. 859 */ 860 static Obj_Entry * 861 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 862 { 863 Obj_Entry *obj; 864 const Elf_Phdr *phlimit = phdr + phnum; 865 const Elf_Phdr *ph; 866 int nsegs = 0; 867 868 obj = obj_new(); 869 for (ph = phdr; ph < phlimit; ph++) { 870 switch (ph->p_type) { 871 872 case PT_PHDR: 873 if ((const Elf_Phdr *)ph->p_vaddr != phdr) { 874 _rtld_error("%s: invalid PT_PHDR", path); 875 return NULL; 876 } 877 obj->phdr = (const Elf_Phdr *) ph->p_vaddr; 878 obj->phsize = ph->p_memsz; 879 break; 880 881 case PT_INTERP: 882 obj->interp = (const char *) ph->p_vaddr; 883 break; 884 885 case PT_LOAD: 886 if (nsegs == 0) { /* First load segment */ 887 obj->vaddrbase = trunc_page(ph->p_vaddr); 888 obj->mapbase = (caddr_t) obj->vaddrbase; 889 obj->relocbase = obj->mapbase - obj->vaddrbase; 890 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 891 obj->vaddrbase; 892 } else { /* Last load segment */ 893 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 894 obj->vaddrbase; 895 } 896 nsegs++; 897 break; 898 899 case PT_DYNAMIC: 900 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; 901 break; 902 903 case PT_TLS: 904 obj->tlsindex = 1; 905 obj->tlssize = ph->p_memsz; 906 obj->tlsalign = ph->p_align; 907 obj->tlsinitsize = ph->p_filesz; 908 obj->tlsinit = (void*) ph->p_vaddr; 909 break; 910 } 911 } 912 if (nsegs < 1) { 913 _rtld_error("%s: too few PT_LOAD segments", path); 914 return NULL; 915 } 916 917 obj->entry = entry; 918 return obj; 919 } 920 921 static Obj_Entry * 922 dlcheck(void *handle) 923 { 924 Obj_Entry *obj; 925 926 for (obj = obj_list; obj != NULL; obj = obj->next) 927 if (obj == (Obj_Entry *) handle) 928 break; 929 930 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 931 _rtld_error("Invalid shared object handle %p", handle); 932 return NULL; 933 } 934 return obj; 935 } 936 937 /* 938 * If the given object is already in the donelist, return true. Otherwise 939 * add the object to the list and return false. 940 */ 941 static bool 942 donelist_check(DoneList *dlp, const Obj_Entry *obj) 943 { 944 unsigned int i; 945 946 for (i = 0; i < dlp->num_used; i++) 947 if (dlp->objs[i] == obj) 948 return true; 949 /* 950 * Our donelist allocation should always be sufficient. But if 951 * our threads locking isn't working properly, more shared objects 952 * could have been loaded since we allocated the list. That should 953 * never happen, but we'll handle it properly just in case it does. 954 */ 955 if (dlp->num_used < dlp->num_alloc) 956 dlp->objs[dlp->num_used++] = obj; 957 return false; 958 } 959 960 /* 961 * Hash function for symbol table lookup. Don't even think about changing 962 * this. It is specified by the System V ABI. 963 */ 964 unsigned long 965 elf_hash(const char *name) 966 { 967 const unsigned char *p = (const unsigned char *) name; 968 unsigned long h = 0; 969 unsigned long g; 970 971 while (*p != '\0') { 972 h = (h << 4) + *p++; 973 if ((g = h & 0xf0000000) != 0) 974 h ^= g >> 24; 975 h &= ~g; 976 } 977 return h; 978 } 979 980 /* 981 * Find the library with the given name, and return its full pathname. 982 * The returned string is dynamically allocated. Generates an error 983 * message and returns NULL if the library cannot be found. 984 * 985 * If the second argument is non-NULL, then it refers to an already- 986 * loaded shared object, whose library search path will be searched. 987 * 988 * The search order is: 989 * LD_LIBRARY_PATH 990 * rpath in the referencing file 991 * ldconfig hints 992 * /lib:/usr/lib 993 */ 994 static char * 995 find_library(const char *xname, const Obj_Entry *refobj) 996 { 997 char *pathname; 998 char *name; 999 1000 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1001 if (xname[0] != '/' && !trust) { 1002 _rtld_error("Absolute pathname required for shared object \"%s\"", 1003 xname); 1004 return NULL; 1005 } 1006 return xstrdup(xname); 1007 } 1008 1009 if (libmap_disable || (refobj == NULL) || 1010 (name = lm_find(refobj->path, xname)) == NULL) 1011 name = (char *)xname; 1012 1013 dbg(" Searching for \"%s\"", name); 1014 1015 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1016 (refobj != NULL && 1017 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1018 (pathname = search_library_path(name, gethints())) != NULL || 1019 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1020 return pathname; 1021 1022 if(refobj != NULL && refobj->path != NULL) { 1023 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1024 name, basename(refobj->path)); 1025 } else { 1026 _rtld_error("Shared object \"%s\" not found", name); 1027 } 1028 return NULL; 1029 } 1030 1031 /* 1032 * Given a symbol number in a referencing object, find the corresponding 1033 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1034 * no definition was found. Returns a pointer to the Obj_Entry of the 1035 * defining object via the reference parameter DEFOBJ_OUT. 1036 */ 1037 const Elf_Sym * 1038 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1039 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1040 { 1041 const Elf_Sym *ref; 1042 const Elf_Sym *def; 1043 const Obj_Entry *defobj; 1044 const Ver_Entry *ventry; 1045 const char *name; 1046 unsigned long hash; 1047 1048 /* 1049 * If we have already found this symbol, get the information from 1050 * the cache. 1051 */ 1052 if (symnum >= refobj->nchains) 1053 return NULL; /* Bad object */ 1054 if (cache != NULL && cache[symnum].sym != NULL) { 1055 *defobj_out = cache[symnum].obj; 1056 return cache[symnum].sym; 1057 } 1058 1059 ref = refobj->symtab + symnum; 1060 name = refobj->strtab + ref->st_name; 1061 defobj = NULL; 1062 1063 /* 1064 * We don't have to do a full scale lookup if the symbol is local. 1065 * We know it will bind to the instance in this load module; to 1066 * which we already have a pointer (ie ref). By not doing a lookup, 1067 * we not only improve performance, but it also avoids unresolvable 1068 * symbols when local symbols are not in the hash table. This has 1069 * been seen with the ia64 toolchain. 1070 */ 1071 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1072 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1073 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1074 symnum); 1075 } 1076 ventry = fetch_ventry(refobj, symnum); 1077 hash = elf_hash(name); 1078 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1079 } else { 1080 def = ref; 1081 defobj = refobj; 1082 } 1083 1084 /* 1085 * If we found no definition and the reference is weak, treat the 1086 * symbol as having the value zero. 1087 */ 1088 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1089 def = &sym_zero; 1090 defobj = obj_main; 1091 } 1092 1093 if (def != NULL) { 1094 *defobj_out = defobj; 1095 /* Record the information in the cache to avoid subsequent lookups. */ 1096 if (cache != NULL) { 1097 cache[symnum].sym = def; 1098 cache[symnum].obj = defobj; 1099 } 1100 } else { 1101 if (refobj != &obj_rtld) 1102 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1103 } 1104 return def; 1105 } 1106 1107 /* 1108 * Return the search path from the ldconfig hints file, reading it if 1109 * necessary. Returns NULL if there are problems with the hints file, 1110 * or if the search path there is empty. 1111 */ 1112 static const char * 1113 gethints(void) 1114 { 1115 static char *hints; 1116 1117 if (hints == NULL) { 1118 int fd; 1119 struct elfhints_hdr hdr; 1120 char *p; 1121 1122 /* Keep from trying again in case the hints file is bad. */ 1123 hints = ""; 1124 1125 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1) 1126 return NULL; 1127 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1128 hdr.magic != ELFHINTS_MAGIC || 1129 hdr.version != 1) { 1130 close(fd); 1131 return NULL; 1132 } 1133 p = xmalloc(hdr.dirlistlen + 1); 1134 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1135 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1136 free(p); 1137 close(fd); 1138 return NULL; 1139 } 1140 hints = p; 1141 close(fd); 1142 } 1143 return hints[0] != '\0' ? hints : NULL; 1144 } 1145 1146 static void 1147 init_dag(Obj_Entry *root) 1148 { 1149 DoneList donelist; 1150 1151 donelist_init(&donelist); 1152 init_dag1(root, root, &donelist); 1153 } 1154 1155 static void 1156 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1157 { 1158 const Needed_Entry *needed; 1159 1160 if (donelist_check(dlp, obj)) 1161 return; 1162 1163 obj->refcount++; 1164 objlist_push_tail(&obj->dldags, root); 1165 objlist_push_tail(&root->dagmembers, obj); 1166 for (needed = obj->needed; needed != NULL; needed = needed->next) 1167 if (needed->obj != NULL) 1168 init_dag1(root, needed->obj, dlp); 1169 } 1170 1171 /* 1172 * Initialize the dynamic linker. The argument is the address at which 1173 * the dynamic linker has been mapped into memory. The primary task of 1174 * this function is to relocate the dynamic linker. 1175 */ 1176 static void 1177 init_rtld(caddr_t mapbase) 1178 { 1179 Obj_Entry objtmp; /* Temporary rtld object */ 1180 1181 /* 1182 * Conjure up an Obj_Entry structure for the dynamic linker. 1183 * 1184 * The "path" member can't be initialized yet because string constatns 1185 * cannot yet be acessed. Below we will set it correctly. 1186 */ 1187 memset(&objtmp, 0, sizeof(objtmp)); 1188 objtmp.path = NULL; 1189 objtmp.rtld = true; 1190 objtmp.mapbase = mapbase; 1191 #ifdef PIC 1192 objtmp.relocbase = mapbase; 1193 #endif 1194 if (RTLD_IS_DYNAMIC()) { 1195 objtmp.dynamic = rtld_dynamic(&objtmp); 1196 digest_dynamic(&objtmp, 1); 1197 assert(objtmp.needed == NULL); 1198 #if !defined(__mips__) 1199 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1200 assert(!objtmp.textrel); 1201 #endif 1202 1203 /* 1204 * Temporarily put the dynamic linker entry into the object list, so 1205 * that symbols can be found. 1206 */ 1207 1208 relocate_objects(&objtmp, true, &objtmp); 1209 } 1210 1211 /* Initialize the object list. */ 1212 obj_tail = &obj_list; 1213 1214 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1215 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1216 1217 /* Replace the path with a dynamically allocated copy. */ 1218 obj_rtld.path = xstrdup(PATH_RTLD); 1219 1220 r_debug.r_brk = r_debug_state; 1221 r_debug.r_state = RT_CONSISTENT; 1222 } 1223 1224 /* 1225 * Add the init functions from a needed object list (and its recursive 1226 * needed objects) to "list". This is not used directly; it is a helper 1227 * function for initlist_add_objects(). The write lock must be held 1228 * when this function is called. 1229 */ 1230 static void 1231 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1232 { 1233 /* Recursively process the successor needed objects. */ 1234 if (needed->next != NULL) 1235 initlist_add_neededs(needed->next, list); 1236 1237 /* Process the current needed object. */ 1238 if (needed->obj != NULL) 1239 initlist_add_objects(needed->obj, &needed->obj->next, list); 1240 } 1241 1242 /* 1243 * Scan all of the DAGs rooted in the range of objects from "obj" to 1244 * "tail" and add their init functions to "list". This recurses over 1245 * the DAGs and ensure the proper init ordering such that each object's 1246 * needed libraries are initialized before the object itself. At the 1247 * same time, this function adds the objects to the global finalization 1248 * list "list_fini" in the opposite order. The write lock must be 1249 * held when this function is called. 1250 */ 1251 static void 1252 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1253 { 1254 if (obj->init_done) 1255 return; 1256 obj->init_done = true; 1257 1258 /* Recursively process the successor objects. */ 1259 if (&obj->next != tail) 1260 initlist_add_objects(obj->next, tail, list); 1261 1262 /* Recursively process the needed objects. */ 1263 if (obj->needed != NULL) 1264 initlist_add_neededs(obj->needed, list); 1265 1266 /* Add the object to the init list. */ 1267 if (obj->init != (Elf_Addr)NULL) 1268 objlist_push_tail(list, obj); 1269 1270 /* Add the object to the global fini list in the reverse order. */ 1271 if (obj->fini != (Elf_Addr)NULL) 1272 objlist_push_head(&list_fini, obj); 1273 } 1274 1275 #ifndef FPTR_TARGET 1276 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1277 #endif 1278 1279 static bool 1280 is_exported(const Elf_Sym *def) 1281 { 1282 Elf_Addr value; 1283 const func_ptr_type *p; 1284 1285 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1286 for (p = exports; *p != NULL; p++) 1287 if (FPTR_TARGET(*p) == value) 1288 return true; 1289 return false; 1290 } 1291 1292 /* 1293 * Given a shared object, traverse its list of needed objects, and load 1294 * each of them. Returns 0 on success. Generates an error message and 1295 * returns -1 on failure. 1296 */ 1297 static int 1298 load_needed_objects(Obj_Entry *first) 1299 { 1300 Obj_Entry *obj; 1301 1302 for (obj = first; obj != NULL; obj = obj->next) { 1303 Needed_Entry *needed; 1304 1305 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1306 needed->obj = load_object(obj->strtab + needed->name, obj); 1307 if (needed->obj == NULL && !ld_tracing) 1308 return -1; 1309 } 1310 } 1311 1312 return 0; 1313 } 1314 1315 static int 1316 load_preload_objects(void) 1317 { 1318 char *p = ld_preload; 1319 static const char delim[] = " \t:;"; 1320 1321 if (p == NULL) 1322 return 0; 1323 1324 p += strspn(p, delim); 1325 while (*p != '\0') { 1326 size_t len = strcspn(p, delim); 1327 char savech; 1328 1329 savech = p[len]; 1330 p[len] = '\0'; 1331 if (load_object(p, NULL) == NULL) 1332 return -1; /* XXX - cleanup */ 1333 p[len] = savech; 1334 p += len; 1335 p += strspn(p, delim); 1336 } 1337 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1338 return 0; 1339 } 1340 1341 /* 1342 * Load a shared object into memory, if it is not already loaded. 1343 * 1344 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1345 * on failure. 1346 */ 1347 static Obj_Entry * 1348 load_object(const char *name, const Obj_Entry *refobj) 1349 { 1350 Obj_Entry *obj; 1351 int fd = -1; 1352 struct stat sb; 1353 char *path; 1354 1355 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1356 if (object_match_name(obj, name)) 1357 return obj; 1358 1359 path = find_library(name, refobj); 1360 if (path == NULL) 1361 return NULL; 1362 1363 /* 1364 * If we didn't find a match by pathname, open the file and check 1365 * again by device and inode. This avoids false mismatches caused 1366 * by multiple links or ".." in pathnames. 1367 * 1368 * To avoid a race, we open the file and use fstat() rather than 1369 * using stat(). 1370 */ 1371 if ((fd = open(path, O_RDONLY)) == -1) { 1372 _rtld_error("Cannot open \"%s\"", path); 1373 free(path); 1374 return NULL; 1375 } 1376 if (fstat(fd, &sb) == -1) { 1377 _rtld_error("Cannot fstat \"%s\"", path); 1378 close(fd); 1379 free(path); 1380 return NULL; 1381 } 1382 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1383 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1384 close(fd); 1385 break; 1386 } 1387 } 1388 if (obj != NULL) { 1389 object_add_name(obj, name); 1390 free(path); 1391 close(fd); 1392 return obj; 1393 } 1394 1395 /* First use of this object, so we must map it in */ 1396 obj = do_load_object(fd, name, path, &sb); 1397 if (obj == NULL) 1398 free(path); 1399 close(fd); 1400 1401 return obj; 1402 } 1403 1404 static Obj_Entry * 1405 do_load_object(int fd, const char *name, char *path, struct stat *sbp) 1406 { 1407 Obj_Entry *obj; 1408 struct statfs fs; 1409 1410 /* 1411 * but first, make sure that environment variables haven't been 1412 * used to circumvent the noexec flag on a filesystem. 1413 */ 1414 if (dangerous_ld_env) { 1415 if (fstatfs(fd, &fs) != 0) { 1416 _rtld_error("Cannot fstatfs \"%s\"", path); 1417 return NULL; 1418 } 1419 if (fs.f_flags & MNT_NOEXEC) { 1420 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1421 return NULL; 1422 } 1423 } 1424 dbg("loading \"%s\"", path); 1425 obj = map_object(fd, path, sbp); 1426 if (obj == NULL) 1427 return NULL; 1428 1429 object_add_name(obj, name); 1430 obj->path = path; 1431 digest_dynamic(obj, 0); 1432 1433 *obj_tail = obj; 1434 obj_tail = &obj->next; 1435 obj_count++; 1436 obj_loads++; 1437 linkmap_add(obj); /* for GDB & dlinfo() */ 1438 1439 dbg(" %p .. %p: %s", obj->mapbase, 1440 obj->mapbase + obj->mapsize - 1, obj->path); 1441 if (obj->textrel) 1442 dbg(" WARNING: %s has impure text", obj->path); 1443 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1444 obj->path); 1445 1446 return obj; 1447 } 1448 1449 static Obj_Entry * 1450 obj_from_addr(const void *addr) 1451 { 1452 Obj_Entry *obj; 1453 1454 for (obj = obj_list; obj != NULL; obj = obj->next) { 1455 if (addr < (void *) obj->mapbase) 1456 continue; 1457 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1458 return obj; 1459 } 1460 return NULL; 1461 } 1462 1463 /* 1464 * Call the finalization functions for each of the objects in "list" 1465 * which are unreferenced. All of the objects are expected to have 1466 * non-NULL fini functions. 1467 */ 1468 static void 1469 objlist_call_fini(Objlist *list, int *lockstate) 1470 { 1471 Objlist_Entry *elm; 1472 char *saved_msg; 1473 1474 /* 1475 * Preserve the current error message since a fini function might 1476 * call into the dynamic linker and overwrite it. 1477 */ 1478 saved_msg = errmsg_save(); 1479 wlock_release(rtld_bind_lock, *lockstate); 1480 STAILQ_FOREACH(elm, list, link) { 1481 if (elm->obj->refcount == 0) { 1482 dbg("calling fini function for %s at %p", elm->obj->path, 1483 (void *)elm->obj->fini); 1484 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1485 elm->obj->path); 1486 call_initfini_pointer(elm->obj, elm->obj->fini); 1487 } 1488 } 1489 *lockstate = wlock_acquire(rtld_bind_lock); 1490 errmsg_restore(saved_msg); 1491 } 1492 1493 /* 1494 * Call the initialization functions for each of the objects in 1495 * "list". All of the objects are expected to have non-NULL init 1496 * functions. 1497 */ 1498 static void 1499 objlist_call_init(Objlist *list, int *lockstate) 1500 { 1501 Objlist_Entry *elm; 1502 char *saved_msg; 1503 1504 /* 1505 * Preserve the current error message since an init function might 1506 * call into the dynamic linker and overwrite it. 1507 */ 1508 saved_msg = errmsg_save(); 1509 wlock_release(rtld_bind_lock, *lockstate); 1510 STAILQ_FOREACH(elm, list, link) { 1511 dbg("calling init function for %s at %p", elm->obj->path, 1512 (void *)elm->obj->init); 1513 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1514 elm->obj->path); 1515 call_initfini_pointer(elm->obj, elm->obj->init); 1516 } 1517 *lockstate = wlock_acquire(rtld_bind_lock); 1518 errmsg_restore(saved_msg); 1519 } 1520 1521 static void 1522 objlist_clear(Objlist *list) 1523 { 1524 Objlist_Entry *elm; 1525 1526 while (!STAILQ_EMPTY(list)) { 1527 elm = STAILQ_FIRST(list); 1528 STAILQ_REMOVE_HEAD(list, link); 1529 free(elm); 1530 } 1531 } 1532 1533 static Objlist_Entry * 1534 objlist_find(Objlist *list, const Obj_Entry *obj) 1535 { 1536 Objlist_Entry *elm; 1537 1538 STAILQ_FOREACH(elm, list, link) 1539 if (elm->obj == obj) 1540 return elm; 1541 return NULL; 1542 } 1543 1544 static void 1545 objlist_init(Objlist *list) 1546 { 1547 STAILQ_INIT(list); 1548 } 1549 1550 static void 1551 objlist_push_head(Objlist *list, Obj_Entry *obj) 1552 { 1553 Objlist_Entry *elm; 1554 1555 elm = NEW(Objlist_Entry); 1556 elm->obj = obj; 1557 STAILQ_INSERT_HEAD(list, elm, link); 1558 } 1559 1560 static void 1561 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1562 { 1563 Objlist_Entry *elm; 1564 1565 elm = NEW(Objlist_Entry); 1566 elm->obj = obj; 1567 STAILQ_INSERT_TAIL(list, elm, link); 1568 } 1569 1570 static void 1571 objlist_remove(Objlist *list, Obj_Entry *obj) 1572 { 1573 Objlist_Entry *elm; 1574 1575 if ((elm = objlist_find(list, obj)) != NULL) { 1576 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1577 free(elm); 1578 } 1579 } 1580 1581 /* 1582 * Remove all of the unreferenced objects from "list". 1583 */ 1584 static void 1585 objlist_remove_unref(Objlist *list) 1586 { 1587 Objlist newlist; 1588 Objlist_Entry *elm; 1589 1590 STAILQ_INIT(&newlist); 1591 while (!STAILQ_EMPTY(list)) { 1592 elm = STAILQ_FIRST(list); 1593 STAILQ_REMOVE_HEAD(list, link); 1594 if (elm->obj->refcount == 0) 1595 free(elm); 1596 else 1597 STAILQ_INSERT_TAIL(&newlist, elm, link); 1598 } 1599 *list = newlist; 1600 } 1601 1602 /* 1603 * Relocate newly-loaded shared objects. The argument is a pointer to 1604 * the Obj_Entry for the first such object. All objects from the first 1605 * to the end of the list of objects are relocated. Returns 0 on success, 1606 * or -1 on failure. 1607 */ 1608 static int 1609 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1610 { 1611 Obj_Entry *obj; 1612 1613 for (obj = first; obj != NULL; obj = obj->next) { 1614 if (obj != rtldobj) 1615 dbg("relocating \"%s\"", obj->path); 1616 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1617 obj->symtab == NULL || obj->strtab == NULL) { 1618 _rtld_error("%s: Shared object has no run-time symbol table", 1619 obj->path); 1620 return -1; 1621 } 1622 1623 if (obj->textrel) { 1624 /* There are relocations to the write-protected text segment. */ 1625 if (mprotect(obj->mapbase, obj->textsize, 1626 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1627 _rtld_error("%s: Cannot write-enable text segment: %s", 1628 obj->path, strerror(errno)); 1629 return -1; 1630 } 1631 } 1632 1633 /* Process the non-PLT relocations. */ 1634 if (reloc_non_plt(obj, rtldobj)) 1635 return -1; 1636 1637 if (obj->textrel) { /* Re-protected the text segment. */ 1638 if (mprotect(obj->mapbase, obj->textsize, 1639 PROT_READ|PROT_EXEC) == -1) { 1640 _rtld_error("%s: Cannot write-protect text segment: %s", 1641 obj->path, strerror(errno)); 1642 return -1; 1643 } 1644 } 1645 1646 /* Process the PLT relocations. */ 1647 if (reloc_plt(obj) == -1) 1648 return -1; 1649 /* Relocate the jump slots if we are doing immediate binding. */ 1650 if (obj->bind_now || bind_now) 1651 if (reloc_jmpslots(obj) == -1) 1652 return -1; 1653 1654 1655 /* 1656 * Set up the magic number and version in the Obj_Entry. These 1657 * were checked in the crt1.o from the original ElfKit, so we 1658 * set them for backward compatibility. 1659 */ 1660 obj->magic = RTLD_MAGIC; 1661 obj->version = RTLD_VERSION; 1662 1663 /* Set the special PLT or GOT entries. */ 1664 init_pltgot(obj); 1665 } 1666 1667 return 0; 1668 } 1669 1670 /* 1671 * Cleanup procedure. It will be called (by the atexit mechanism) just 1672 * before the process exits. 1673 */ 1674 static void 1675 rtld_exit(void) 1676 { 1677 Obj_Entry *obj; 1678 int lockstate; 1679 1680 lockstate = wlock_acquire(rtld_bind_lock); 1681 dbg("rtld_exit()"); 1682 /* Clear all the reference counts so the fini functions will be called. */ 1683 for (obj = obj_list; obj != NULL; obj = obj->next) 1684 obj->refcount = 0; 1685 objlist_call_fini(&list_fini, &lockstate); 1686 /* No need to remove the items from the list, since we are exiting. */ 1687 if (!libmap_disable) 1688 lm_fini(); 1689 wlock_release(rtld_bind_lock, lockstate); 1690 } 1691 1692 static void * 1693 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1694 { 1695 #ifdef COMPAT_32BIT 1696 const char *trans; 1697 #endif 1698 if (path == NULL) 1699 return (NULL); 1700 1701 path += strspn(path, ":;"); 1702 while (*path != '\0') { 1703 size_t len; 1704 char *res; 1705 1706 len = strcspn(path, ":;"); 1707 #ifdef COMPAT_32BIT 1708 trans = lm_findn(NULL, path, len); 1709 if (trans) 1710 res = callback(trans, strlen(trans), arg); 1711 else 1712 #endif 1713 res = callback(path, len, arg); 1714 1715 if (res != NULL) 1716 return (res); 1717 1718 path += len; 1719 path += strspn(path, ":;"); 1720 } 1721 1722 return (NULL); 1723 } 1724 1725 struct try_library_args { 1726 const char *name; 1727 size_t namelen; 1728 char *buffer; 1729 size_t buflen; 1730 }; 1731 1732 static void * 1733 try_library_path(const char *dir, size_t dirlen, void *param) 1734 { 1735 struct try_library_args *arg; 1736 1737 arg = param; 1738 if (*dir == '/' || trust) { 1739 char *pathname; 1740 1741 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1742 return (NULL); 1743 1744 pathname = arg->buffer; 1745 strncpy(pathname, dir, dirlen); 1746 pathname[dirlen] = '/'; 1747 strcpy(pathname + dirlen + 1, arg->name); 1748 1749 dbg(" Trying \"%s\"", pathname); 1750 if (access(pathname, F_OK) == 0) { /* We found it */ 1751 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1752 strcpy(pathname, arg->buffer); 1753 return (pathname); 1754 } 1755 } 1756 return (NULL); 1757 } 1758 1759 static char * 1760 search_library_path(const char *name, const char *path) 1761 { 1762 char *p; 1763 struct try_library_args arg; 1764 1765 if (path == NULL) 1766 return NULL; 1767 1768 arg.name = name; 1769 arg.namelen = strlen(name); 1770 arg.buffer = xmalloc(PATH_MAX); 1771 arg.buflen = PATH_MAX; 1772 1773 p = path_enumerate(path, try_library_path, &arg); 1774 1775 free(arg.buffer); 1776 1777 return (p); 1778 } 1779 1780 int 1781 dlclose(void *handle) 1782 { 1783 Obj_Entry *root; 1784 int lockstate; 1785 1786 lockstate = wlock_acquire(rtld_bind_lock); 1787 root = dlcheck(handle); 1788 if (root == NULL) { 1789 wlock_release(rtld_bind_lock, lockstate); 1790 return -1; 1791 } 1792 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1793 root->path); 1794 1795 /* Unreference the object and its dependencies. */ 1796 root->dl_refcount--; 1797 1798 unref_dag(root); 1799 1800 if (root->refcount == 0) { 1801 /* 1802 * The object is no longer referenced, so we must unload it. 1803 * First, call the fini functions. 1804 */ 1805 objlist_call_fini(&list_fini, &lockstate); 1806 objlist_remove_unref(&list_fini); 1807 1808 /* Finish cleaning up the newly-unreferenced objects. */ 1809 GDB_STATE(RT_DELETE,&root->linkmap); 1810 unload_object(root); 1811 GDB_STATE(RT_CONSISTENT,NULL); 1812 } 1813 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1814 wlock_release(rtld_bind_lock, lockstate); 1815 return 0; 1816 } 1817 1818 const char * 1819 dlerror(void) 1820 { 1821 char *msg = error_message; 1822 error_message = NULL; 1823 return msg; 1824 } 1825 1826 /* 1827 * This function is deprecated and has no effect. 1828 */ 1829 void 1830 dllockinit(void *context, 1831 void *(*lock_create)(void *context), 1832 void (*rlock_acquire)(void *lock), 1833 void (*wlock_acquire)(void *lock), 1834 void (*lock_release)(void *lock), 1835 void (*lock_destroy)(void *lock), 1836 void (*context_destroy)(void *context)) 1837 { 1838 static void *cur_context; 1839 static void (*cur_context_destroy)(void *); 1840 1841 /* Just destroy the context from the previous call, if necessary. */ 1842 if (cur_context_destroy != NULL) 1843 cur_context_destroy(cur_context); 1844 cur_context = context; 1845 cur_context_destroy = context_destroy; 1846 } 1847 1848 void * 1849 dlopen(const char *name, int mode) 1850 { 1851 Obj_Entry **old_obj_tail; 1852 Obj_Entry *obj; 1853 Objlist initlist; 1854 int result, lockstate; 1855 1856 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 1857 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1858 if (ld_tracing != NULL) 1859 environ = (char **)*get_program_var_addr("environ"); 1860 1861 objlist_init(&initlist); 1862 1863 lockstate = wlock_acquire(rtld_bind_lock); 1864 GDB_STATE(RT_ADD,NULL); 1865 1866 old_obj_tail = obj_tail; 1867 obj = NULL; 1868 if (name == NULL) { 1869 obj = obj_main; 1870 obj->refcount++; 1871 } else { 1872 obj = load_object(name, obj_main); 1873 } 1874 1875 if (obj) { 1876 obj->dl_refcount++; 1877 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 1878 objlist_push_tail(&list_global, obj); 1879 mode &= RTLD_MODEMASK; 1880 if (*old_obj_tail != NULL) { /* We loaded something new. */ 1881 assert(*old_obj_tail == obj); 1882 result = load_needed_objects(obj); 1883 init_dag(obj); 1884 if (result != -1) 1885 result = rtld_verify_versions(&obj->dagmembers); 1886 if (result != -1 && ld_tracing) 1887 goto trace; 1888 if (result == -1 || 1889 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 1890 obj->dl_refcount--; 1891 unref_dag(obj); 1892 if (obj->refcount == 0) 1893 unload_object(obj); 1894 obj = NULL; 1895 } else { 1896 /* Make list of init functions to call. */ 1897 initlist_add_objects(obj, &obj->next, &initlist); 1898 } 1899 } else { 1900 1901 /* Bump the reference counts for objects on this DAG. */ 1902 ref_dag(obj); 1903 1904 if (ld_tracing) 1905 goto trace; 1906 } 1907 } 1908 1909 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 1910 name); 1911 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 1912 1913 /* Call the init functions. */ 1914 objlist_call_init(&initlist, &lockstate); 1915 objlist_clear(&initlist); 1916 wlock_release(rtld_bind_lock, lockstate); 1917 return obj; 1918 trace: 1919 trace_loaded_objects(obj); 1920 wlock_release(rtld_bind_lock, lockstate); 1921 exit(0); 1922 } 1923 1924 static void * 1925 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 1926 int flags) 1927 { 1928 DoneList donelist; 1929 const Obj_Entry *obj, *defobj; 1930 const Elf_Sym *def, *symp; 1931 unsigned long hash; 1932 int lockstate; 1933 1934 hash = elf_hash(name); 1935 def = NULL; 1936 defobj = NULL; 1937 flags |= SYMLOOK_IN_PLT; 1938 1939 lockstate = rlock_acquire(rtld_bind_lock); 1940 if (handle == NULL || handle == RTLD_NEXT || 1941 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 1942 1943 if ((obj = obj_from_addr(retaddr)) == NULL) { 1944 _rtld_error("Cannot determine caller's shared object"); 1945 rlock_release(rtld_bind_lock, lockstate); 1946 return NULL; 1947 } 1948 if (handle == NULL) { /* Just the caller's shared object. */ 1949 def = symlook_obj(name, hash, obj, ve, flags); 1950 defobj = obj; 1951 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 1952 handle == RTLD_SELF) { /* ... caller included */ 1953 if (handle == RTLD_NEXT) 1954 obj = obj->next; 1955 for (; obj != NULL; obj = obj->next) { 1956 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 1957 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 1958 def = symp; 1959 defobj = obj; 1960 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 1961 break; 1962 } 1963 } 1964 } 1965 /* 1966 * Search the dynamic linker itself, and possibly resolve the 1967 * symbol from there. This is how the application links to 1968 * dynamic linker services such as dlopen. Only the values listed 1969 * in the "exports" array can be resolved from the dynamic linker. 1970 */ 1971 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 1972 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 1973 if (symp != NULL && is_exported(symp)) { 1974 def = symp; 1975 defobj = &obj_rtld; 1976 } 1977 } 1978 } else { 1979 assert(handle == RTLD_DEFAULT); 1980 def = symlook_default(name, hash, obj, &defobj, ve, flags); 1981 } 1982 } else { 1983 if ((obj = dlcheck(handle)) == NULL) { 1984 rlock_release(rtld_bind_lock, lockstate); 1985 return NULL; 1986 } 1987 1988 donelist_init(&donelist); 1989 if (obj->mainprog) { 1990 /* Search main program and all libraries loaded by it. */ 1991 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 1992 &donelist); 1993 } else { 1994 Needed_Entry fake; 1995 1996 /* Search the whole DAG rooted at the given object. */ 1997 fake.next = NULL; 1998 fake.obj = (Obj_Entry *)obj; 1999 fake.name = 0; 2000 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2001 &donelist); 2002 } 2003 } 2004 2005 if (def != NULL) { 2006 rlock_release(rtld_bind_lock, lockstate); 2007 2008 /* 2009 * The value required by the caller is derived from the value 2010 * of the symbol. For the ia64 architecture, we need to 2011 * construct a function descriptor which the caller can use to 2012 * call the function with the right 'gp' value. For other 2013 * architectures and for non-functions, the value is simply 2014 * the relocated value of the symbol. 2015 */ 2016 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2017 return make_function_pointer(def, defobj); 2018 else 2019 return defobj->relocbase + def->st_value; 2020 } 2021 2022 _rtld_error("Undefined symbol \"%s\"", name); 2023 rlock_release(rtld_bind_lock, lockstate); 2024 return NULL; 2025 } 2026 2027 void * 2028 dlsym(void *handle, const char *name) 2029 { 2030 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2031 SYMLOOK_DLSYM); 2032 } 2033 2034 void * 2035 dlvsym(void *handle, const char *name, const char *version) 2036 { 2037 Ver_Entry ventry; 2038 2039 ventry.name = version; 2040 ventry.file = NULL; 2041 ventry.hash = elf_hash(version); 2042 ventry.flags= 0; 2043 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2044 SYMLOOK_DLSYM); 2045 } 2046 2047 int 2048 dladdr(const void *addr, Dl_info *info) 2049 { 2050 const Obj_Entry *obj; 2051 const Elf_Sym *def; 2052 void *symbol_addr; 2053 unsigned long symoffset; 2054 int lockstate; 2055 2056 lockstate = rlock_acquire(rtld_bind_lock); 2057 obj = obj_from_addr(addr); 2058 if (obj == NULL) { 2059 _rtld_error("No shared object contains address"); 2060 rlock_release(rtld_bind_lock, lockstate); 2061 return 0; 2062 } 2063 info->dli_fname = obj->path; 2064 info->dli_fbase = obj->mapbase; 2065 info->dli_saddr = (void *)0; 2066 info->dli_sname = NULL; 2067 2068 /* 2069 * Walk the symbol list looking for the symbol whose address is 2070 * closest to the address sent in. 2071 */ 2072 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2073 def = obj->symtab + symoffset; 2074 2075 /* 2076 * For skip the symbol if st_shndx is either SHN_UNDEF or 2077 * SHN_COMMON. 2078 */ 2079 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2080 continue; 2081 2082 /* 2083 * If the symbol is greater than the specified address, or if it 2084 * is further away from addr than the current nearest symbol, 2085 * then reject it. 2086 */ 2087 symbol_addr = obj->relocbase + def->st_value; 2088 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2089 continue; 2090 2091 /* Update our idea of the nearest symbol. */ 2092 info->dli_sname = obj->strtab + def->st_name; 2093 info->dli_saddr = symbol_addr; 2094 2095 /* Exact match? */ 2096 if (info->dli_saddr == addr) 2097 break; 2098 } 2099 rlock_release(rtld_bind_lock, lockstate); 2100 return 1; 2101 } 2102 2103 int 2104 dlinfo(void *handle, int request, void *p) 2105 { 2106 const Obj_Entry *obj; 2107 int error, lockstate; 2108 2109 lockstate = rlock_acquire(rtld_bind_lock); 2110 2111 if (handle == NULL || handle == RTLD_SELF) { 2112 void *retaddr; 2113 2114 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2115 if ((obj = obj_from_addr(retaddr)) == NULL) 2116 _rtld_error("Cannot determine caller's shared object"); 2117 } else 2118 obj = dlcheck(handle); 2119 2120 if (obj == NULL) { 2121 rlock_release(rtld_bind_lock, lockstate); 2122 return (-1); 2123 } 2124 2125 error = 0; 2126 switch (request) { 2127 case RTLD_DI_LINKMAP: 2128 *((struct link_map const **)p) = &obj->linkmap; 2129 break; 2130 case RTLD_DI_ORIGIN: 2131 error = rtld_dirname(obj->path, p); 2132 break; 2133 2134 case RTLD_DI_SERINFOSIZE: 2135 case RTLD_DI_SERINFO: 2136 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2137 break; 2138 2139 default: 2140 _rtld_error("Invalid request %d passed to dlinfo()", request); 2141 error = -1; 2142 } 2143 2144 rlock_release(rtld_bind_lock, lockstate); 2145 2146 return (error); 2147 } 2148 2149 int 2150 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2151 { 2152 struct dl_phdr_info phdr_info; 2153 const Obj_Entry *obj; 2154 int error, bind_lockstate, phdr_lockstate; 2155 2156 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2157 bind_lockstate = rlock_acquire(rtld_bind_lock); 2158 2159 error = 0; 2160 2161 for (obj = obj_list; obj != NULL; obj = obj->next) { 2162 phdr_info.dlpi_addr = (Elf_Addr)obj->relocbase; 2163 phdr_info.dlpi_name = STAILQ_FIRST(&obj->names) ? 2164 STAILQ_FIRST(&obj->names)->name : obj->path; 2165 phdr_info.dlpi_phdr = obj->phdr; 2166 phdr_info.dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2167 phdr_info.dlpi_tls_modid = obj->tlsindex; 2168 phdr_info.dlpi_tls_data = obj->tlsinit; 2169 phdr_info.dlpi_adds = obj_loads; 2170 phdr_info.dlpi_subs = obj_loads - obj_count; 2171 2172 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2173 break; 2174 2175 } 2176 rlock_release(rtld_bind_lock, bind_lockstate); 2177 wlock_release(rtld_phdr_lock, phdr_lockstate); 2178 2179 return (error); 2180 } 2181 2182 struct fill_search_info_args { 2183 int request; 2184 unsigned int flags; 2185 Dl_serinfo *serinfo; 2186 Dl_serpath *serpath; 2187 char *strspace; 2188 }; 2189 2190 static void * 2191 fill_search_info(const char *dir, size_t dirlen, void *param) 2192 { 2193 struct fill_search_info_args *arg; 2194 2195 arg = param; 2196 2197 if (arg->request == RTLD_DI_SERINFOSIZE) { 2198 arg->serinfo->dls_cnt ++; 2199 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2200 } else { 2201 struct dl_serpath *s_entry; 2202 2203 s_entry = arg->serpath; 2204 s_entry->dls_name = arg->strspace; 2205 s_entry->dls_flags = arg->flags; 2206 2207 strncpy(arg->strspace, dir, dirlen); 2208 arg->strspace[dirlen] = '\0'; 2209 2210 arg->strspace += dirlen + 1; 2211 arg->serpath++; 2212 } 2213 2214 return (NULL); 2215 } 2216 2217 static int 2218 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2219 { 2220 struct dl_serinfo _info; 2221 struct fill_search_info_args args; 2222 2223 args.request = RTLD_DI_SERINFOSIZE; 2224 args.serinfo = &_info; 2225 2226 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2227 _info.dls_cnt = 0; 2228 2229 path_enumerate(ld_library_path, fill_search_info, &args); 2230 path_enumerate(obj->rpath, fill_search_info, &args); 2231 path_enumerate(gethints(), fill_search_info, &args); 2232 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2233 2234 2235 if (request == RTLD_DI_SERINFOSIZE) { 2236 info->dls_size = _info.dls_size; 2237 info->dls_cnt = _info.dls_cnt; 2238 return (0); 2239 } 2240 2241 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2242 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2243 return (-1); 2244 } 2245 2246 args.request = RTLD_DI_SERINFO; 2247 args.serinfo = info; 2248 args.serpath = &info->dls_serpath[0]; 2249 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2250 2251 args.flags = LA_SER_LIBPATH; 2252 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2253 return (-1); 2254 2255 args.flags = LA_SER_RUNPATH; 2256 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2257 return (-1); 2258 2259 args.flags = LA_SER_CONFIG; 2260 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2261 return (-1); 2262 2263 args.flags = LA_SER_DEFAULT; 2264 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2265 return (-1); 2266 return (0); 2267 } 2268 2269 static int 2270 rtld_dirname(const char *path, char *bname) 2271 { 2272 const char *endp; 2273 2274 /* Empty or NULL string gets treated as "." */ 2275 if (path == NULL || *path == '\0') { 2276 bname[0] = '.'; 2277 bname[1] = '\0'; 2278 return (0); 2279 } 2280 2281 /* Strip trailing slashes */ 2282 endp = path + strlen(path) - 1; 2283 while (endp > path && *endp == '/') 2284 endp--; 2285 2286 /* Find the start of the dir */ 2287 while (endp > path && *endp != '/') 2288 endp--; 2289 2290 /* Either the dir is "/" or there are no slashes */ 2291 if (endp == path) { 2292 bname[0] = *endp == '/' ? '/' : '.'; 2293 bname[1] = '\0'; 2294 return (0); 2295 } else { 2296 do { 2297 endp--; 2298 } while (endp > path && *endp == '/'); 2299 } 2300 2301 if (endp - path + 2 > PATH_MAX) 2302 { 2303 _rtld_error("Filename is too long: %s", path); 2304 return(-1); 2305 } 2306 2307 strncpy(bname, path, endp - path + 1); 2308 bname[endp - path + 1] = '\0'; 2309 return (0); 2310 } 2311 2312 static void 2313 linkmap_add(Obj_Entry *obj) 2314 { 2315 struct link_map *l = &obj->linkmap; 2316 struct link_map *prev; 2317 2318 obj->linkmap.l_name = obj->path; 2319 obj->linkmap.l_addr = obj->mapbase; 2320 obj->linkmap.l_ld = obj->dynamic; 2321 #ifdef __mips__ 2322 /* GDB needs load offset on MIPS to use the symbols */ 2323 obj->linkmap.l_offs = obj->relocbase; 2324 #endif 2325 2326 if (r_debug.r_map == NULL) { 2327 r_debug.r_map = l; 2328 return; 2329 } 2330 2331 /* 2332 * Scan to the end of the list, but not past the entry for the 2333 * dynamic linker, which we want to keep at the very end. 2334 */ 2335 for (prev = r_debug.r_map; 2336 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2337 prev = prev->l_next) 2338 ; 2339 2340 /* Link in the new entry. */ 2341 l->l_prev = prev; 2342 l->l_next = prev->l_next; 2343 if (l->l_next != NULL) 2344 l->l_next->l_prev = l; 2345 prev->l_next = l; 2346 } 2347 2348 static void 2349 linkmap_delete(Obj_Entry *obj) 2350 { 2351 struct link_map *l = &obj->linkmap; 2352 2353 if (l->l_prev == NULL) { 2354 if ((r_debug.r_map = l->l_next) != NULL) 2355 l->l_next->l_prev = NULL; 2356 return; 2357 } 2358 2359 if ((l->l_prev->l_next = l->l_next) != NULL) 2360 l->l_next->l_prev = l->l_prev; 2361 } 2362 2363 /* 2364 * Function for the debugger to set a breakpoint on to gain control. 2365 * 2366 * The two parameters allow the debugger to easily find and determine 2367 * what the runtime loader is doing and to whom it is doing it. 2368 * 2369 * When the loadhook trap is hit (r_debug_state, set at program 2370 * initialization), the arguments can be found on the stack: 2371 * 2372 * +8 struct link_map *m 2373 * +4 struct r_debug *rd 2374 * +0 RetAddr 2375 */ 2376 void 2377 r_debug_state(struct r_debug* rd, struct link_map *m) 2378 { 2379 } 2380 2381 /* 2382 * Get address of the pointer variable in the main program. 2383 */ 2384 static const void ** 2385 get_program_var_addr(const char *name) 2386 { 2387 const Obj_Entry *obj; 2388 unsigned long hash; 2389 2390 hash = elf_hash(name); 2391 for (obj = obj_main; obj != NULL; obj = obj->next) { 2392 const Elf_Sym *def; 2393 2394 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2395 const void **addr; 2396 2397 addr = (const void **)(obj->relocbase + def->st_value); 2398 return addr; 2399 } 2400 } 2401 return NULL; 2402 } 2403 2404 /* 2405 * Set a pointer variable in the main program to the given value. This 2406 * is used to set key variables such as "environ" before any of the 2407 * init functions are called. 2408 */ 2409 static void 2410 set_program_var(const char *name, const void *value) 2411 { 2412 const void **addr; 2413 2414 if ((addr = get_program_var_addr(name)) != NULL) { 2415 dbg("\"%s\": *%p <-- %p", name, addr, value); 2416 *addr = value; 2417 } 2418 } 2419 2420 /* 2421 * Given a symbol name in a referencing object, find the corresponding 2422 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2423 * no definition was found. Returns a pointer to the Obj_Entry of the 2424 * defining object via the reference parameter DEFOBJ_OUT. 2425 */ 2426 static const Elf_Sym * 2427 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2428 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2429 { 2430 DoneList donelist; 2431 const Elf_Sym *def; 2432 const Elf_Sym *symp; 2433 const Obj_Entry *obj; 2434 const Obj_Entry *defobj; 2435 const Objlist_Entry *elm; 2436 def = NULL; 2437 defobj = NULL; 2438 donelist_init(&donelist); 2439 2440 /* Look first in the referencing object if linked symbolically. */ 2441 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2442 symp = symlook_obj(name, hash, refobj, ventry, flags); 2443 if (symp != NULL) { 2444 def = symp; 2445 defobj = refobj; 2446 } 2447 } 2448 2449 /* Search all objects loaded at program start up. */ 2450 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2451 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2452 &donelist); 2453 if (symp != NULL && 2454 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2455 def = symp; 2456 defobj = obj; 2457 } 2458 } 2459 2460 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2461 STAILQ_FOREACH(elm, &list_global, link) { 2462 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2463 break; 2464 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2465 flags, &donelist); 2466 if (symp != NULL && 2467 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2468 def = symp; 2469 defobj = obj; 2470 } 2471 } 2472 2473 /* Search all dlopened DAGs containing the referencing object. */ 2474 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2475 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2476 break; 2477 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2478 flags, &donelist); 2479 if (symp != NULL && 2480 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2481 def = symp; 2482 defobj = obj; 2483 } 2484 } 2485 2486 /* 2487 * Search the dynamic linker itself, and possibly resolve the 2488 * symbol from there. This is how the application links to 2489 * dynamic linker services such as dlopen. Only the values listed 2490 * in the "exports" array can be resolved from the dynamic linker. 2491 */ 2492 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2493 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2494 if (symp != NULL && is_exported(symp)) { 2495 def = symp; 2496 defobj = &obj_rtld; 2497 } 2498 } 2499 2500 if (def != NULL) 2501 *defobj_out = defobj; 2502 return def; 2503 } 2504 2505 static const Elf_Sym * 2506 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2507 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2508 DoneList *dlp) 2509 { 2510 const Elf_Sym *symp; 2511 const Elf_Sym *def; 2512 const Obj_Entry *defobj; 2513 const Objlist_Entry *elm; 2514 2515 def = NULL; 2516 defobj = NULL; 2517 STAILQ_FOREACH(elm, objlist, link) { 2518 if (donelist_check(dlp, elm->obj)) 2519 continue; 2520 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2521 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2522 def = symp; 2523 defobj = elm->obj; 2524 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2525 break; 2526 } 2527 } 2528 } 2529 if (def != NULL) 2530 *defobj_out = defobj; 2531 return def; 2532 } 2533 2534 /* 2535 * Search the symbol table of a shared object and all objects needed 2536 * by it for a symbol of the given name. Search order is 2537 * breadth-first. Returns a pointer to the symbol, or NULL if no 2538 * definition was found. 2539 */ 2540 static const Elf_Sym * 2541 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2542 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2543 DoneList *dlp) 2544 { 2545 const Elf_Sym *def, *def_w; 2546 const Needed_Entry *n; 2547 const Obj_Entry *obj, *defobj, *defobj1; 2548 2549 def = def_w = NULL; 2550 defobj = NULL; 2551 for (n = needed; n != NULL; n = n->next) { 2552 if ((obj = n->obj) == NULL || 2553 donelist_check(dlp, obj) || 2554 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2555 continue; 2556 defobj = obj; 2557 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2558 *defobj_out = defobj; 2559 return (def); 2560 } 2561 } 2562 /* 2563 * There we come when either symbol definition is not found in 2564 * directly needed objects, or found symbol is weak. 2565 */ 2566 for (n = needed; n != NULL; n = n->next) { 2567 if ((obj = n->obj) == NULL) 2568 continue; 2569 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2570 ventry, flags, dlp); 2571 if (def_w == NULL) 2572 continue; 2573 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2574 def = def_w; 2575 defobj = defobj1; 2576 } 2577 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2578 break; 2579 } 2580 if (def != NULL) 2581 *defobj_out = defobj; 2582 return (def); 2583 } 2584 2585 /* 2586 * Search the symbol table of a single shared object for a symbol of 2587 * the given name and version, if requested. Returns a pointer to the 2588 * symbol, or NULL if no definition was found. 2589 * 2590 * The symbol's hash value is passed in for efficiency reasons; that 2591 * eliminates many recomputations of the hash value. 2592 */ 2593 const Elf_Sym * 2594 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2595 const Ver_Entry *ventry, int flags) 2596 { 2597 unsigned long symnum; 2598 const Elf_Sym *vsymp; 2599 Elf_Versym verndx; 2600 int vcount; 2601 2602 if (obj->buckets == NULL) 2603 return NULL; 2604 2605 vsymp = NULL; 2606 vcount = 0; 2607 symnum = obj->buckets[hash % obj->nbuckets]; 2608 2609 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2610 const Elf_Sym *symp; 2611 const char *strp; 2612 2613 if (symnum >= obj->nchains) 2614 return NULL; /* Bad object */ 2615 2616 symp = obj->symtab + symnum; 2617 strp = obj->strtab + symp->st_name; 2618 2619 switch (ELF_ST_TYPE(symp->st_info)) { 2620 case STT_FUNC: 2621 case STT_NOTYPE: 2622 case STT_OBJECT: 2623 if (symp->st_value == 0) 2624 continue; 2625 /* fallthrough */ 2626 case STT_TLS: 2627 if (symp->st_shndx != SHN_UNDEF) 2628 break; 2629 #ifndef __mips__ 2630 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2631 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2632 break; 2633 /* fallthrough */ 2634 #endif 2635 default: 2636 continue; 2637 } 2638 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2639 continue; 2640 2641 if (ventry == NULL) { 2642 if (obj->versyms != NULL) { 2643 verndx = VER_NDX(obj->versyms[symnum]); 2644 if (verndx > obj->vernum) { 2645 _rtld_error("%s: symbol %s references wrong version %d", 2646 obj->path, obj->strtab + symnum, verndx); 2647 continue; 2648 } 2649 /* 2650 * If we are not called from dlsym (i.e. this is a normal 2651 * relocation from unversioned binary, accept the symbol 2652 * immediately if it happens to have first version after 2653 * this shared object became versioned. Otherwise, if 2654 * symbol is versioned and not hidden, remember it. If it 2655 * is the only symbol with this name exported by the 2656 * shared object, it will be returned as a match at the 2657 * end of the function. If symbol is global (verndx < 2) 2658 * accept it unconditionally. 2659 */ 2660 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2661 return symp; 2662 else if (verndx >= VER_NDX_GIVEN) { 2663 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2664 if (vsymp == NULL) 2665 vsymp = symp; 2666 vcount ++; 2667 } 2668 continue; 2669 } 2670 } 2671 return symp; 2672 } else { 2673 if (obj->versyms == NULL) { 2674 if (object_match_name(obj, ventry->name)) { 2675 _rtld_error("%s: object %s should provide version %s for " 2676 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2677 obj->strtab + symnum); 2678 continue; 2679 } 2680 } else { 2681 verndx = VER_NDX(obj->versyms[symnum]); 2682 if (verndx > obj->vernum) { 2683 _rtld_error("%s: symbol %s references wrong version %d", 2684 obj->path, obj->strtab + symnum, verndx); 2685 continue; 2686 } 2687 if (obj->vertab[verndx].hash != ventry->hash || 2688 strcmp(obj->vertab[verndx].name, ventry->name)) { 2689 /* 2690 * Version does not match. Look if this is a global symbol 2691 * and if it is not hidden. If global symbol (verndx < 2) 2692 * is available, use it. Do not return symbol if we are 2693 * called by dlvsym, because dlvsym looks for a specific 2694 * version and default one is not what dlvsym wants. 2695 */ 2696 if ((flags & SYMLOOK_DLSYM) || 2697 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2698 (verndx >= VER_NDX_GIVEN)) 2699 continue; 2700 } 2701 } 2702 return symp; 2703 } 2704 } 2705 return (vcount == 1) ? vsymp : NULL; 2706 } 2707 2708 static void 2709 trace_loaded_objects(Obj_Entry *obj) 2710 { 2711 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2712 int c; 2713 2714 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2715 main_local = ""; 2716 2717 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2718 fmt1 = "\t%o => %p (%x)\n"; 2719 2720 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2721 fmt2 = "\t%o (%x)\n"; 2722 2723 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2724 2725 for (; obj; obj = obj->next) { 2726 Needed_Entry *needed; 2727 char *name, *path; 2728 bool is_lib; 2729 2730 if (list_containers && obj->needed != NULL) 2731 printf("%s:\n", obj->path); 2732 for (needed = obj->needed; needed; needed = needed->next) { 2733 if (needed->obj != NULL) { 2734 if (needed->obj->traced && !list_containers) 2735 continue; 2736 needed->obj->traced = true; 2737 path = needed->obj->path; 2738 } else 2739 path = "not found"; 2740 2741 name = (char *)obj->strtab + needed->name; 2742 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2743 2744 fmt = is_lib ? fmt1 : fmt2; 2745 while ((c = *fmt++) != '\0') { 2746 switch (c) { 2747 default: 2748 putchar(c); 2749 continue; 2750 case '\\': 2751 switch (c = *fmt) { 2752 case '\0': 2753 continue; 2754 case 'n': 2755 putchar('\n'); 2756 break; 2757 case 't': 2758 putchar('\t'); 2759 break; 2760 } 2761 break; 2762 case '%': 2763 switch (c = *fmt) { 2764 case '\0': 2765 continue; 2766 case '%': 2767 default: 2768 putchar(c); 2769 break; 2770 case 'A': 2771 printf("%s", main_local); 2772 break; 2773 case 'a': 2774 printf("%s", obj_main->path); 2775 break; 2776 case 'o': 2777 printf("%s", name); 2778 break; 2779 #if 0 2780 case 'm': 2781 printf("%d", sodp->sod_major); 2782 break; 2783 case 'n': 2784 printf("%d", sodp->sod_minor); 2785 break; 2786 #endif 2787 case 'p': 2788 printf("%s", path); 2789 break; 2790 case 'x': 2791 printf("%p", needed->obj ? needed->obj->mapbase : 0); 2792 break; 2793 } 2794 break; 2795 } 2796 ++fmt; 2797 } 2798 } 2799 } 2800 } 2801 2802 /* 2803 * Unload a dlopened object and its dependencies from memory and from 2804 * our data structures. It is assumed that the DAG rooted in the 2805 * object has already been unreferenced, and that the object has a 2806 * reference count of 0. 2807 */ 2808 static void 2809 unload_object(Obj_Entry *root) 2810 { 2811 Obj_Entry *obj; 2812 Obj_Entry **linkp; 2813 2814 assert(root->refcount == 0); 2815 2816 /* 2817 * Pass over the DAG removing unreferenced objects from 2818 * appropriate lists. 2819 */ 2820 unlink_object(root); 2821 2822 /* Unmap all objects that are no longer referenced. */ 2823 linkp = &obj_list->next; 2824 while ((obj = *linkp) != NULL) { 2825 if (obj->refcount == 0) { 2826 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2827 obj->path); 2828 dbg("unloading \"%s\"", obj->path); 2829 munmap(obj->mapbase, obj->mapsize); 2830 linkmap_delete(obj); 2831 *linkp = obj->next; 2832 obj_count--; 2833 obj_free(obj); 2834 } else 2835 linkp = &obj->next; 2836 } 2837 obj_tail = linkp; 2838 } 2839 2840 static void 2841 unlink_object(Obj_Entry *root) 2842 { 2843 Objlist_Entry *elm; 2844 2845 if (root->refcount == 0) { 2846 /* Remove the object from the RTLD_GLOBAL list. */ 2847 objlist_remove(&list_global, root); 2848 2849 /* Remove the object from all objects' DAG lists. */ 2850 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2851 objlist_remove(&elm->obj->dldags, root); 2852 if (elm->obj != root) 2853 unlink_object(elm->obj); 2854 } 2855 } 2856 } 2857 2858 static void 2859 ref_dag(Obj_Entry *root) 2860 { 2861 Objlist_Entry *elm; 2862 2863 STAILQ_FOREACH(elm, &root->dagmembers, link) 2864 elm->obj->refcount++; 2865 } 2866 2867 static void 2868 unref_dag(Obj_Entry *root) 2869 { 2870 Objlist_Entry *elm; 2871 2872 STAILQ_FOREACH(elm, &root->dagmembers, link) 2873 elm->obj->refcount--; 2874 } 2875 2876 /* 2877 * Common code for MD __tls_get_addr(). 2878 */ 2879 void * 2880 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 2881 { 2882 Elf_Addr* dtv = *dtvp; 2883 int lockstate; 2884 2885 /* Check dtv generation in case new modules have arrived */ 2886 if (dtv[0] != tls_dtv_generation) { 2887 Elf_Addr* newdtv; 2888 int to_copy; 2889 2890 lockstate = wlock_acquire(rtld_bind_lock); 2891 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 2892 to_copy = dtv[1]; 2893 if (to_copy > tls_max_index) 2894 to_copy = tls_max_index; 2895 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 2896 newdtv[0] = tls_dtv_generation; 2897 newdtv[1] = tls_max_index; 2898 free(dtv); 2899 wlock_release(rtld_bind_lock, lockstate); 2900 *dtvp = newdtv; 2901 } 2902 2903 /* Dynamically allocate module TLS if necessary */ 2904 if (!dtv[index + 1]) { 2905 /* Signal safe, wlock will block out signals. */ 2906 lockstate = wlock_acquire(rtld_bind_lock); 2907 if (!dtv[index + 1]) 2908 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 2909 wlock_release(rtld_bind_lock, lockstate); 2910 } 2911 return (void*) (dtv[index + 1] + offset); 2912 } 2913 2914 /* XXX not sure what variants to use for arm. */ 2915 2916 #if defined(__ia64__) || defined(__powerpc__) 2917 2918 /* 2919 * Allocate Static TLS using the Variant I method. 2920 */ 2921 void * 2922 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 2923 { 2924 Obj_Entry *obj; 2925 char *tcb; 2926 Elf_Addr **tls; 2927 Elf_Addr *dtv; 2928 Elf_Addr addr; 2929 int i; 2930 2931 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 2932 return (oldtcb); 2933 2934 assert(tcbsize >= TLS_TCB_SIZE); 2935 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 2936 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 2937 2938 if (oldtcb != NULL) { 2939 memcpy(tls, oldtcb, tls_static_space); 2940 free(oldtcb); 2941 2942 /* Adjust the DTV. */ 2943 dtv = tls[0]; 2944 for (i = 0; i < dtv[1]; i++) { 2945 if (dtv[i+2] >= (Elf_Addr)oldtcb && 2946 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 2947 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 2948 } 2949 } 2950 } else { 2951 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 2952 tls[0] = dtv; 2953 dtv[0] = tls_dtv_generation; 2954 dtv[1] = tls_max_index; 2955 2956 for (obj = objs; obj; obj = obj->next) { 2957 if (obj->tlsoffset) { 2958 addr = (Elf_Addr)tls + obj->tlsoffset; 2959 memset((void*) (addr + obj->tlsinitsize), 2960 0, obj->tlssize - obj->tlsinitsize); 2961 if (obj->tlsinit) 2962 memcpy((void*) addr, obj->tlsinit, 2963 obj->tlsinitsize); 2964 dtv[obj->tlsindex + 1] = addr; 2965 } 2966 } 2967 } 2968 2969 return (tcb); 2970 } 2971 2972 void 2973 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 2974 { 2975 Elf_Addr *dtv; 2976 Elf_Addr tlsstart, tlsend; 2977 int dtvsize, i; 2978 2979 assert(tcbsize >= TLS_TCB_SIZE); 2980 2981 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 2982 tlsend = tlsstart + tls_static_space; 2983 2984 dtv = *(Elf_Addr **)tlsstart; 2985 dtvsize = dtv[1]; 2986 for (i = 0; i < dtvsize; i++) { 2987 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 2988 free((void*)dtv[i+2]); 2989 } 2990 } 2991 free(dtv); 2992 free(tcb); 2993 } 2994 2995 #endif 2996 2997 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 2998 defined(__arm__) || defined(__mips__) 2999 3000 /* 3001 * Allocate Static TLS using the Variant II method. 3002 */ 3003 void * 3004 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3005 { 3006 Obj_Entry *obj; 3007 size_t size; 3008 char *tls; 3009 Elf_Addr *dtv, *olddtv; 3010 Elf_Addr segbase, oldsegbase, addr; 3011 int i; 3012 3013 size = round(tls_static_space, tcbalign); 3014 3015 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3016 tls = calloc(1, size + tcbsize); 3017 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3018 3019 segbase = (Elf_Addr)(tls + size); 3020 ((Elf_Addr*)segbase)[0] = segbase; 3021 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3022 3023 dtv[0] = tls_dtv_generation; 3024 dtv[1] = tls_max_index; 3025 3026 if (oldtls) { 3027 /* 3028 * Copy the static TLS block over whole. 3029 */ 3030 oldsegbase = (Elf_Addr) oldtls; 3031 memcpy((void *)(segbase - tls_static_space), 3032 (const void *)(oldsegbase - tls_static_space), 3033 tls_static_space); 3034 3035 /* 3036 * If any dynamic TLS blocks have been created tls_get_addr(), 3037 * move them over. 3038 */ 3039 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3040 for (i = 0; i < olddtv[1]; i++) { 3041 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3042 dtv[i+2] = olddtv[i+2]; 3043 olddtv[i+2] = 0; 3044 } 3045 } 3046 3047 /* 3048 * We assume that this block was the one we created with 3049 * allocate_initial_tls(). 3050 */ 3051 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3052 } else { 3053 for (obj = objs; obj; obj = obj->next) { 3054 if (obj->tlsoffset) { 3055 addr = segbase - obj->tlsoffset; 3056 memset((void*) (addr + obj->tlsinitsize), 3057 0, obj->tlssize - obj->tlsinitsize); 3058 if (obj->tlsinit) 3059 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3060 dtv[obj->tlsindex + 1] = addr; 3061 } 3062 } 3063 } 3064 3065 return (void*) segbase; 3066 } 3067 3068 void 3069 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3070 { 3071 size_t size; 3072 Elf_Addr* dtv; 3073 int dtvsize, i; 3074 Elf_Addr tlsstart, tlsend; 3075 3076 /* 3077 * Figure out the size of the initial TLS block so that we can 3078 * find stuff which ___tls_get_addr() allocated dynamically. 3079 */ 3080 size = round(tls_static_space, tcbalign); 3081 3082 dtv = ((Elf_Addr**)tls)[1]; 3083 dtvsize = dtv[1]; 3084 tlsend = (Elf_Addr) tls; 3085 tlsstart = tlsend - size; 3086 for (i = 0; i < dtvsize; i++) { 3087 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3088 free((void*) dtv[i+2]); 3089 } 3090 } 3091 3092 free((void*) tlsstart); 3093 free((void*) dtv); 3094 } 3095 3096 #endif 3097 3098 /* 3099 * Allocate TLS block for module with given index. 3100 */ 3101 void * 3102 allocate_module_tls(int index) 3103 { 3104 Obj_Entry* obj; 3105 char* p; 3106 3107 for (obj = obj_list; obj; obj = obj->next) { 3108 if (obj->tlsindex == index) 3109 break; 3110 } 3111 if (!obj) { 3112 _rtld_error("Can't find module with TLS index %d", index); 3113 die(); 3114 } 3115 3116 p = malloc(obj->tlssize); 3117 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3118 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3119 3120 return p; 3121 } 3122 3123 bool 3124 allocate_tls_offset(Obj_Entry *obj) 3125 { 3126 size_t off; 3127 3128 if (obj->tls_done) 3129 return true; 3130 3131 if (obj->tlssize == 0) { 3132 obj->tls_done = true; 3133 return true; 3134 } 3135 3136 if (obj->tlsindex == 1) 3137 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3138 else 3139 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3140 obj->tlssize, obj->tlsalign); 3141 3142 /* 3143 * If we have already fixed the size of the static TLS block, we 3144 * must stay within that size. When allocating the static TLS, we 3145 * leave a small amount of space spare to be used for dynamically 3146 * loading modules which use static TLS. 3147 */ 3148 if (tls_static_space) { 3149 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3150 return false; 3151 } 3152 3153 tls_last_offset = obj->tlsoffset = off; 3154 tls_last_size = obj->tlssize; 3155 obj->tls_done = true; 3156 3157 return true; 3158 } 3159 3160 void 3161 free_tls_offset(Obj_Entry *obj) 3162 { 3163 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3164 defined(__arm__) || defined(__mips__) 3165 /* 3166 * If we were the last thing to allocate out of the static TLS 3167 * block, we give our space back to the 'allocator'. This is a 3168 * simplistic workaround to allow libGL.so.1 to be loaded and 3169 * unloaded multiple times. We only handle the Variant II 3170 * mechanism for now - this really needs a proper allocator. 3171 */ 3172 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3173 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3174 tls_last_offset -= obj->tlssize; 3175 tls_last_size = 0; 3176 } 3177 #endif 3178 } 3179 3180 void * 3181 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3182 { 3183 void *ret; 3184 int lockstate; 3185 3186 lockstate = wlock_acquire(rtld_bind_lock); 3187 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3188 wlock_release(rtld_bind_lock, lockstate); 3189 return (ret); 3190 } 3191 3192 void 3193 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3194 { 3195 int lockstate; 3196 3197 lockstate = wlock_acquire(rtld_bind_lock); 3198 free_tls(tcb, tcbsize, tcbalign); 3199 wlock_release(rtld_bind_lock, lockstate); 3200 } 3201 3202 static void 3203 object_add_name(Obj_Entry *obj, const char *name) 3204 { 3205 Name_Entry *entry; 3206 size_t len; 3207 3208 len = strlen(name); 3209 entry = malloc(sizeof(Name_Entry) + len); 3210 3211 if (entry != NULL) { 3212 strcpy(entry->name, name); 3213 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3214 } 3215 } 3216 3217 static int 3218 object_match_name(const Obj_Entry *obj, const char *name) 3219 { 3220 Name_Entry *entry; 3221 3222 STAILQ_FOREACH(entry, &obj->names, link) { 3223 if (strcmp(name, entry->name) == 0) 3224 return (1); 3225 } 3226 return (0); 3227 } 3228 3229 static Obj_Entry * 3230 locate_dependency(const Obj_Entry *obj, const char *name) 3231 { 3232 const Objlist_Entry *entry; 3233 const Needed_Entry *needed; 3234 3235 STAILQ_FOREACH(entry, &list_main, link) { 3236 if (object_match_name(entry->obj, name)) 3237 return entry->obj; 3238 } 3239 3240 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3241 if (needed->obj == NULL) 3242 continue; 3243 if (object_match_name(needed->obj, name)) 3244 return needed->obj; 3245 } 3246 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3247 obj->path, name); 3248 die(); 3249 } 3250 3251 static int 3252 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3253 const Elf_Vernaux *vna) 3254 { 3255 const Elf_Verdef *vd; 3256 const char *vername; 3257 3258 vername = refobj->strtab + vna->vna_name; 3259 vd = depobj->verdef; 3260 if (vd == NULL) { 3261 _rtld_error("%s: version %s required by %s not defined", 3262 depobj->path, vername, refobj->path); 3263 return (-1); 3264 } 3265 for (;;) { 3266 if (vd->vd_version != VER_DEF_CURRENT) { 3267 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3268 depobj->path, vd->vd_version); 3269 return (-1); 3270 } 3271 if (vna->vna_hash == vd->vd_hash) { 3272 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3273 ((char *)vd + vd->vd_aux); 3274 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3275 return (0); 3276 } 3277 if (vd->vd_next == 0) 3278 break; 3279 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3280 } 3281 if (vna->vna_flags & VER_FLG_WEAK) 3282 return (0); 3283 _rtld_error("%s: version %s required by %s not found", 3284 depobj->path, vername, refobj->path); 3285 return (-1); 3286 } 3287 3288 static int 3289 rtld_verify_object_versions(Obj_Entry *obj) 3290 { 3291 const Elf_Verneed *vn; 3292 const Elf_Verdef *vd; 3293 const Elf_Verdaux *vda; 3294 const Elf_Vernaux *vna; 3295 const Obj_Entry *depobj; 3296 int maxvernum, vernum; 3297 3298 maxvernum = 0; 3299 /* 3300 * Walk over defined and required version records and figure out 3301 * max index used by any of them. Do very basic sanity checking 3302 * while there. 3303 */ 3304 vn = obj->verneed; 3305 while (vn != NULL) { 3306 if (vn->vn_version != VER_NEED_CURRENT) { 3307 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3308 obj->path, vn->vn_version); 3309 return (-1); 3310 } 3311 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3312 for (;;) { 3313 vernum = VER_NEED_IDX(vna->vna_other); 3314 if (vernum > maxvernum) 3315 maxvernum = vernum; 3316 if (vna->vna_next == 0) 3317 break; 3318 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3319 } 3320 if (vn->vn_next == 0) 3321 break; 3322 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3323 } 3324 3325 vd = obj->verdef; 3326 while (vd != NULL) { 3327 if (vd->vd_version != VER_DEF_CURRENT) { 3328 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3329 obj->path, vd->vd_version); 3330 return (-1); 3331 } 3332 vernum = VER_DEF_IDX(vd->vd_ndx); 3333 if (vernum > maxvernum) 3334 maxvernum = vernum; 3335 if (vd->vd_next == 0) 3336 break; 3337 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3338 } 3339 3340 if (maxvernum == 0) 3341 return (0); 3342 3343 /* 3344 * Store version information in array indexable by version index. 3345 * Verify that object version requirements are satisfied along the 3346 * way. 3347 */ 3348 obj->vernum = maxvernum + 1; 3349 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3350 3351 vd = obj->verdef; 3352 while (vd != NULL) { 3353 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3354 vernum = VER_DEF_IDX(vd->vd_ndx); 3355 assert(vernum <= maxvernum); 3356 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3357 obj->vertab[vernum].hash = vd->vd_hash; 3358 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3359 obj->vertab[vernum].file = NULL; 3360 obj->vertab[vernum].flags = 0; 3361 } 3362 if (vd->vd_next == 0) 3363 break; 3364 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3365 } 3366 3367 vn = obj->verneed; 3368 while (vn != NULL) { 3369 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3370 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3371 for (;;) { 3372 if (check_object_provided_version(obj, depobj, vna)) 3373 return (-1); 3374 vernum = VER_NEED_IDX(vna->vna_other); 3375 assert(vernum <= maxvernum); 3376 obj->vertab[vernum].hash = vna->vna_hash; 3377 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3378 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3379 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3380 VER_INFO_HIDDEN : 0; 3381 if (vna->vna_next == 0) 3382 break; 3383 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3384 } 3385 if (vn->vn_next == 0) 3386 break; 3387 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3388 } 3389 return 0; 3390 } 3391 3392 static int 3393 rtld_verify_versions(const Objlist *objlist) 3394 { 3395 Objlist_Entry *entry; 3396 int rc; 3397 3398 rc = 0; 3399 STAILQ_FOREACH(entry, objlist, link) { 3400 /* 3401 * Skip dummy objects or objects that have their version requirements 3402 * already checked. 3403 */ 3404 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3405 continue; 3406 if (rtld_verify_object_versions(entry->obj) == -1) { 3407 rc = -1; 3408 if (ld_tracing == NULL) 3409 break; 3410 } 3411 } 3412 if (rc == 0 || ld_tracing != NULL) 3413 rc = rtld_verify_object_versions(&obj_rtld); 3414 return rc; 3415 } 3416 3417 const Ver_Entry * 3418 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3419 { 3420 Elf_Versym vernum; 3421 3422 if (obj->vertab) { 3423 vernum = VER_NDX(obj->versyms[symnum]); 3424 if (vernum >= obj->vernum) { 3425 _rtld_error("%s: symbol %s has wrong verneed value %d", 3426 obj->path, obj->strtab + symnum, vernum); 3427 } else if (obj->vertab[vernum].hash != 0) { 3428 return &obj->vertab[vernum]; 3429 } 3430 } 3431 return NULL; 3432 } 3433