1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/sysctl.h> 44 #include <sys/uio.h> 45 #include <sys/utsname.h> 46 #include <sys/ktrace.h> 47 48 #include <dlfcn.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <stdarg.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 #include "debug.h" 59 #include "rtld.h" 60 #include "libmap.h" 61 #include "rtld_tls.h" 62 63 #ifndef COMPAT_32BIT 64 #define PATH_RTLD "/libexec/ld-elf.so.1" 65 #else 66 #define PATH_RTLD "/libexec/ld-elf32.so.1" 67 #endif 68 69 /* Types. */ 70 typedef void (*func_ptr_type)(); 71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73 /* 74 * This structure provides a reentrant way to keep a list of objects and 75 * check which ones have already been processed in some way. 76 */ 77 typedef struct Struct_DoneList { 78 const Obj_Entry **objs; /* Array of object pointers */ 79 unsigned int num_alloc; /* Allocated size of the array */ 80 unsigned int num_used; /* Number of array slots used */ 81 } DoneList; 82 83 /* 84 * Function declarations. 85 */ 86 static const char *basename(const char *); 87 static void die(void) __dead2; 88 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 89 const Elf_Dyn **); 90 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 91 static void digest_dynamic(Obj_Entry *, int); 92 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 93 static Obj_Entry *dlcheck(void *); 94 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 95 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 96 static bool donelist_check(DoneList *, const Obj_Entry *); 97 static void errmsg_restore(char *); 98 static char *errmsg_save(void); 99 static void *fill_search_info(const char *, size_t, void *); 100 static char *find_library(const char *, const Obj_Entry *); 101 static const char *gethints(void); 102 static void init_dag(Obj_Entry *); 103 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 104 static void init_rtld(caddr_t, Elf_Auxinfo **); 105 static void initlist_add_neededs(Needed_Entry *, Objlist *); 106 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 107 static void linkmap_add(Obj_Entry *); 108 static void linkmap_delete(Obj_Entry *); 109 static int load_needed_objects(Obj_Entry *, int); 110 static int load_preload_objects(void); 111 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 112 static Obj_Entry *obj_from_addr(const void *); 113 static void objlist_call_fini(Objlist *, bool, int *); 114 static void objlist_call_init(Objlist *, int *); 115 static void objlist_clear(Objlist *); 116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117 static void objlist_init(Objlist *); 118 static void objlist_push_head(Objlist *, Obj_Entry *); 119 static void objlist_push_tail(Objlist *, Obj_Entry *); 120 static void objlist_remove(Objlist *, Obj_Entry *); 121 static void *path_enumerate(const char *, path_enum_proc, void *); 122 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 123 static int rtld_dirname(const char *, char *); 124 static int rtld_dirname_abs(const char *, char *); 125 static void rtld_exit(void); 126 static char *search_library_path(const char *, const char *); 127 static const void **get_program_var_addr(const char *); 128 static void set_program_var(const char *, const void *); 129 static const Elf_Sym *symlook_default(const char *, unsigned long, 130 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 131 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 132 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 133 static const Elf_Sym *symlook_needed(const char *, unsigned long, 134 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 135 int, DoneList *); 136 static void trace_loaded_objects(Obj_Entry *); 137 static void unlink_object(Obj_Entry *); 138 static void unload_object(Obj_Entry *); 139 static void unref_dag(Obj_Entry *); 140 static void ref_dag(Obj_Entry *); 141 static int origin_subst_one(char **, const char *, const char *, 142 const char *, char *); 143 static char *origin_subst(const char *, const char *); 144 static int rtld_verify_versions(const Objlist *); 145 static int rtld_verify_object_versions(Obj_Entry *); 146 static void object_add_name(Obj_Entry *, const char *); 147 static int object_match_name(const Obj_Entry *, const char *); 148 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 149 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 150 struct dl_phdr_info *phdr_info); 151 152 void r_debug_state(struct r_debug *, struct link_map *); 153 154 /* 155 * Data declarations. 156 */ 157 static char *error_message; /* Message for dlerror(), or NULL */ 158 struct r_debug r_debug; /* for GDB; */ 159 static bool libmap_disable; /* Disable libmap */ 160 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 161 static bool trust; /* False for setuid and setgid programs */ 162 static bool dangerous_ld_env; /* True if environment variables have been 163 used to affect the libraries loaded */ 164 static char *ld_bind_now; /* Environment variable for immediate binding */ 165 static char *ld_debug; /* Environment variable for debugging */ 166 static char *ld_library_path; /* Environment variable for search path */ 167 static char *ld_preload; /* Environment variable for libraries to 168 load first */ 169 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 170 static char *ld_tracing; /* Called from ldd to print libs */ 171 static char *ld_utrace; /* Use utrace() to log events. */ 172 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 173 static Obj_Entry **obj_tail; /* Link field of last object in list */ 174 static Obj_Entry *obj_main; /* The main program shared object */ 175 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 176 static unsigned int obj_count; /* Number of objects in obj_list */ 177 static unsigned int obj_loads; /* Number of objects in obj_list */ 178 179 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 180 STAILQ_HEAD_INITIALIZER(list_global); 181 static Objlist list_main = /* Objects loaded at program startup */ 182 STAILQ_HEAD_INITIALIZER(list_main); 183 static Objlist list_fini = /* Objects needing fini() calls */ 184 STAILQ_HEAD_INITIALIZER(list_fini); 185 186 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 187 188 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 189 190 extern Elf_Dyn _DYNAMIC; 191 #pragma weak _DYNAMIC 192 #ifndef RTLD_IS_DYNAMIC 193 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 194 #endif 195 196 int osreldate, pagesize; 197 198 /* 199 * Global declarations normally provided by crt1. The dynamic linker is 200 * not built with crt1, so we have to provide them ourselves. 201 */ 202 char *__progname; 203 char **environ; 204 205 /* 206 * Globals to control TLS allocation. 207 */ 208 size_t tls_last_offset; /* Static TLS offset of last module */ 209 size_t tls_last_size; /* Static TLS size of last module */ 210 size_t tls_static_space; /* Static TLS space allocated */ 211 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 212 int tls_max_index = 1; /* Largest module index allocated */ 213 214 /* 215 * Fill in a DoneList with an allocation large enough to hold all of 216 * the currently-loaded objects. Keep this as a macro since it calls 217 * alloca and we want that to occur within the scope of the caller. 218 */ 219 #define donelist_init(dlp) \ 220 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 221 assert((dlp)->objs != NULL), \ 222 (dlp)->num_alloc = obj_count, \ 223 (dlp)->num_used = 0) 224 225 #define UTRACE_DLOPEN_START 1 226 #define UTRACE_DLOPEN_STOP 2 227 #define UTRACE_DLCLOSE_START 3 228 #define UTRACE_DLCLOSE_STOP 4 229 #define UTRACE_LOAD_OBJECT 5 230 #define UTRACE_UNLOAD_OBJECT 6 231 #define UTRACE_ADD_RUNDEP 7 232 #define UTRACE_PRELOAD_FINISHED 8 233 #define UTRACE_INIT_CALL 9 234 #define UTRACE_FINI_CALL 10 235 236 struct utrace_rtld { 237 char sig[4]; /* 'RTLD' */ 238 int event; 239 void *handle; 240 void *mapbase; /* Used for 'parent' and 'init/fini' */ 241 size_t mapsize; 242 int refcnt; /* Used for 'mode' */ 243 char name[MAXPATHLEN]; 244 }; 245 246 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 247 if (ld_utrace != NULL) \ 248 ld_utrace_log(e, h, mb, ms, r, n); \ 249 } while (0) 250 251 static void 252 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 253 int refcnt, const char *name) 254 { 255 struct utrace_rtld ut; 256 257 ut.sig[0] = 'R'; 258 ut.sig[1] = 'T'; 259 ut.sig[2] = 'L'; 260 ut.sig[3] = 'D'; 261 ut.event = event; 262 ut.handle = handle; 263 ut.mapbase = mapbase; 264 ut.mapsize = mapsize; 265 ut.refcnt = refcnt; 266 bzero(ut.name, sizeof(ut.name)); 267 if (name) 268 strlcpy(ut.name, name, sizeof(ut.name)); 269 utrace(&ut, sizeof(ut)); 270 } 271 272 /* 273 * Main entry point for dynamic linking. The first argument is the 274 * stack pointer. The stack is expected to be laid out as described 275 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 276 * Specifically, the stack pointer points to a word containing 277 * ARGC. Following that in the stack is a null-terminated sequence 278 * of pointers to argument strings. Then comes a null-terminated 279 * sequence of pointers to environment strings. Finally, there is a 280 * sequence of "auxiliary vector" entries. 281 * 282 * The second argument points to a place to store the dynamic linker's 283 * exit procedure pointer and the third to a place to store the main 284 * program's object. 285 * 286 * The return value is the main program's entry point. 287 */ 288 func_ptr_type 289 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 290 { 291 Elf_Auxinfo *aux_info[AT_COUNT]; 292 int i; 293 int argc; 294 char **argv; 295 char **env; 296 Elf_Auxinfo *aux; 297 Elf_Auxinfo *auxp; 298 const char *argv0; 299 Objlist_Entry *entry; 300 Obj_Entry *obj; 301 Obj_Entry **preload_tail; 302 Objlist initlist; 303 int lockstate; 304 305 /* 306 * On entry, the dynamic linker itself has not been relocated yet. 307 * Be very careful not to reference any global data until after 308 * init_rtld has returned. It is OK to reference file-scope statics 309 * and string constants, and to call static and global functions. 310 */ 311 312 /* Find the auxiliary vector on the stack. */ 313 argc = *sp++; 314 argv = (char **) sp; 315 sp += argc + 1; /* Skip over arguments and NULL terminator */ 316 env = (char **) sp; 317 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 318 ; 319 aux = (Elf_Auxinfo *) sp; 320 321 /* Digest the auxiliary vector. */ 322 for (i = 0; i < AT_COUNT; i++) 323 aux_info[i] = NULL; 324 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 325 if (auxp->a_type < AT_COUNT) 326 aux_info[auxp->a_type] = auxp; 327 } 328 329 /* Initialize and relocate ourselves. */ 330 assert(aux_info[AT_BASE] != NULL); 331 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 332 333 __progname = obj_rtld.path; 334 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 335 environ = env; 336 337 trust = !issetugid(); 338 339 ld_bind_now = getenv(LD_ "BIND_NOW"); 340 /* 341 * If the process is tainted, then we un-set the dangerous environment 342 * variables. The process will be marked as tainted until setuid(2) 343 * is called. If any child process calls setuid(2) we do not want any 344 * future processes to honor the potentially un-safe variables. 345 */ 346 if (!trust) { 347 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 348 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 349 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH")) { 350 _rtld_error("environment corrupt; aborting"); 351 die(); 352 } 353 } 354 ld_debug = getenv(LD_ "DEBUG"); 355 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 356 libmap_override = getenv(LD_ "LIBMAP"); 357 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 358 ld_preload = getenv(LD_ "PRELOAD"); 359 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 360 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 361 (ld_library_path != NULL) || (ld_preload != NULL) || 362 (ld_elf_hints_path != NULL); 363 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 364 ld_utrace = getenv(LD_ "UTRACE"); 365 366 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 367 ld_elf_hints_path = _PATH_ELF_HINTS; 368 369 if (ld_debug != NULL && *ld_debug != '\0') 370 debug = 1; 371 dbg("%s is initialized, base address = %p", __progname, 372 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 373 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 374 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 375 376 /* 377 * Load the main program, or process its program header if it is 378 * already loaded. 379 */ 380 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 381 int fd = aux_info[AT_EXECFD]->a_un.a_val; 382 dbg("loading main program"); 383 obj_main = map_object(fd, argv0, NULL); 384 close(fd); 385 if (obj_main == NULL) 386 die(); 387 } else { /* Main program already loaded. */ 388 const Elf_Phdr *phdr; 389 int phnum; 390 caddr_t entry; 391 392 dbg("processing main program's program header"); 393 assert(aux_info[AT_PHDR] != NULL); 394 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 395 assert(aux_info[AT_PHNUM] != NULL); 396 phnum = aux_info[AT_PHNUM]->a_un.a_val; 397 assert(aux_info[AT_PHENT] != NULL); 398 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 399 assert(aux_info[AT_ENTRY] != NULL); 400 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 401 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 402 die(); 403 } 404 405 if (aux_info[AT_EXECPATH] != 0) { 406 char *kexecpath; 407 char buf[MAXPATHLEN]; 408 409 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 410 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 411 if (kexecpath[0] == '/') 412 obj_main->path = kexecpath; 413 else if (getcwd(buf, sizeof(buf)) == NULL || 414 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 415 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 416 obj_main->path = xstrdup(argv0); 417 else 418 obj_main->path = xstrdup(buf); 419 } else { 420 dbg("No AT_EXECPATH"); 421 obj_main->path = xstrdup(argv0); 422 } 423 dbg("obj_main path %s", obj_main->path); 424 obj_main->mainprog = true; 425 426 /* 427 * Get the actual dynamic linker pathname from the executable if 428 * possible. (It should always be possible.) That ensures that 429 * gdb will find the right dynamic linker even if a non-standard 430 * one is being used. 431 */ 432 if (obj_main->interp != NULL && 433 strcmp(obj_main->interp, obj_rtld.path) != 0) { 434 free(obj_rtld.path); 435 obj_rtld.path = xstrdup(obj_main->interp); 436 __progname = obj_rtld.path; 437 } 438 439 digest_dynamic(obj_main, 0); 440 441 linkmap_add(obj_main); 442 linkmap_add(&obj_rtld); 443 444 /* Link the main program into the list of objects. */ 445 *obj_tail = obj_main; 446 obj_tail = &obj_main->next; 447 obj_count++; 448 obj_loads++; 449 /* Make sure we don't call the main program's init and fini functions. */ 450 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 451 452 /* Initialize a fake symbol for resolving undefined weak references. */ 453 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 454 sym_zero.st_shndx = SHN_UNDEF; 455 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 456 457 if (!libmap_disable) 458 libmap_disable = (bool)lm_init(libmap_override); 459 460 dbg("loading LD_PRELOAD libraries"); 461 if (load_preload_objects() == -1) 462 die(); 463 preload_tail = obj_tail; 464 465 dbg("loading needed objects"); 466 if (load_needed_objects(obj_main, 0) == -1) 467 die(); 468 469 /* Make a list of all objects loaded at startup. */ 470 for (obj = obj_list; obj != NULL; obj = obj->next) { 471 objlist_push_tail(&list_main, obj); 472 obj->refcount++; 473 } 474 475 dbg("checking for required versions"); 476 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 477 die(); 478 479 if (ld_tracing) { /* We're done */ 480 trace_loaded_objects(obj_main); 481 exit(0); 482 } 483 484 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 485 dump_relocations(obj_main); 486 exit (0); 487 } 488 489 /* setup TLS for main thread */ 490 dbg("initializing initial thread local storage"); 491 STAILQ_FOREACH(entry, &list_main, link) { 492 /* 493 * Allocate all the initial objects out of the static TLS 494 * block even if they didn't ask for it. 495 */ 496 allocate_tls_offset(entry->obj); 497 } 498 allocate_initial_tls(obj_list); 499 500 if (relocate_objects(obj_main, 501 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 502 die(); 503 504 dbg("doing copy relocations"); 505 if (do_copy_relocations(obj_main) == -1) 506 die(); 507 508 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 509 dump_relocations(obj_main); 510 exit (0); 511 } 512 513 dbg("initializing key program variables"); 514 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 515 set_program_var("environ", env); 516 set_program_var("__elf_aux_vector", aux); 517 518 dbg("initializing thread locks"); 519 lockdflt_init(); 520 521 /* Make a list of init functions to call. */ 522 objlist_init(&initlist); 523 initlist_add_objects(obj_list, preload_tail, &initlist); 524 525 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 526 527 lockstate = wlock_acquire(rtld_bind_lock); 528 objlist_call_init(&initlist, &lockstate); 529 objlist_clear(&initlist); 530 wlock_release(rtld_bind_lock, lockstate); 531 532 dbg("transferring control to program entry point = %p", obj_main->entry); 533 534 /* Return the exit procedure and the program entry point. */ 535 *exit_proc = rtld_exit; 536 *objp = obj_main; 537 return (func_ptr_type) obj_main->entry; 538 } 539 540 Elf_Addr 541 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 542 { 543 const Elf_Rel *rel; 544 const Elf_Sym *def; 545 const Obj_Entry *defobj; 546 Elf_Addr *where; 547 Elf_Addr target; 548 int lockstate; 549 550 lockstate = rlock_acquire(rtld_bind_lock); 551 if (obj->pltrel) 552 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 553 else 554 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 555 556 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 557 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 558 if (def == NULL) 559 die(); 560 561 target = (Elf_Addr)(defobj->relocbase + def->st_value); 562 563 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 564 defobj->strtab + def->st_name, basename(obj->path), 565 (void *)target, basename(defobj->path)); 566 567 /* 568 * Write the new contents for the jmpslot. Note that depending on 569 * architecture, the value which we need to return back to the 570 * lazy binding trampoline may or may not be the target 571 * address. The value returned from reloc_jmpslot() is the value 572 * that the trampoline needs. 573 */ 574 target = reloc_jmpslot(where, target, defobj, obj, rel); 575 rlock_release(rtld_bind_lock, lockstate); 576 return target; 577 } 578 579 /* 580 * Error reporting function. Use it like printf. If formats the message 581 * into a buffer, and sets things up so that the next call to dlerror() 582 * will return the message. 583 */ 584 void 585 _rtld_error(const char *fmt, ...) 586 { 587 static char buf[512]; 588 va_list ap; 589 590 va_start(ap, fmt); 591 vsnprintf(buf, sizeof buf, fmt, ap); 592 error_message = buf; 593 va_end(ap); 594 } 595 596 /* 597 * Return a dynamically-allocated copy of the current error message, if any. 598 */ 599 static char * 600 errmsg_save(void) 601 { 602 return error_message == NULL ? NULL : xstrdup(error_message); 603 } 604 605 /* 606 * Restore the current error message from a copy which was previously saved 607 * by errmsg_save(). The copy is freed. 608 */ 609 static void 610 errmsg_restore(char *saved_msg) 611 { 612 if (saved_msg == NULL) 613 error_message = NULL; 614 else { 615 _rtld_error("%s", saved_msg); 616 free(saved_msg); 617 } 618 } 619 620 static const char * 621 basename(const char *name) 622 { 623 const char *p = strrchr(name, '/'); 624 return p != NULL ? p + 1 : name; 625 } 626 627 static struct utsname uts; 628 629 static int 630 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 631 char *may_free) 632 { 633 const char *p, *p1; 634 char *res1; 635 int subst_len; 636 int kw_len; 637 638 res1 = *res = NULL; 639 p = real; 640 subst_len = kw_len = 0; 641 for (;;) { 642 p1 = strstr(p, kw); 643 if (p1 != NULL) { 644 if (subst_len == 0) { 645 subst_len = strlen(subst); 646 kw_len = strlen(kw); 647 } 648 if (*res == NULL) { 649 *res = xmalloc(PATH_MAX); 650 res1 = *res; 651 } 652 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 653 _rtld_error("Substitution of %s in %s cannot be performed", 654 kw, real); 655 if (may_free != NULL) 656 free(may_free); 657 free(res); 658 return (false); 659 } 660 memcpy(res1, p, p1 - p); 661 res1 += p1 - p; 662 memcpy(res1, subst, subst_len); 663 res1 += subst_len; 664 p = p1 + kw_len; 665 } else { 666 if (*res == NULL) { 667 if (may_free != NULL) 668 *res = may_free; 669 else 670 *res = xstrdup(real); 671 return (true); 672 } 673 *res1 = '\0'; 674 if (may_free != NULL) 675 free(may_free); 676 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 677 free(res); 678 return (false); 679 } 680 return (true); 681 } 682 } 683 } 684 685 static char * 686 origin_subst(const char *real, const char *origin_path) 687 { 688 char *res1, *res2, *res3, *res4; 689 690 if (uts.sysname[0] == '\0') { 691 if (uname(&uts) != 0) { 692 _rtld_error("utsname failed: %d", errno); 693 return (NULL); 694 } 695 } 696 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 697 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 698 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 699 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 700 return (NULL); 701 return (res4); 702 } 703 704 static void 705 die(void) 706 { 707 const char *msg = dlerror(); 708 709 if (msg == NULL) 710 msg = "Fatal error"; 711 errx(1, "%s", msg); 712 } 713 714 /* 715 * Process a shared object's DYNAMIC section, and save the important 716 * information in its Obj_Entry structure. 717 */ 718 static void 719 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 720 const Elf_Dyn **dyn_soname) 721 { 722 const Elf_Dyn *dynp; 723 Needed_Entry **needed_tail = &obj->needed; 724 int plttype = DT_REL; 725 726 *dyn_rpath = NULL; 727 *dyn_soname = NULL; 728 729 obj->bind_now = false; 730 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 731 switch (dynp->d_tag) { 732 733 case DT_REL: 734 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 735 break; 736 737 case DT_RELSZ: 738 obj->relsize = dynp->d_un.d_val; 739 break; 740 741 case DT_RELENT: 742 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 743 break; 744 745 case DT_JMPREL: 746 obj->pltrel = (const Elf_Rel *) 747 (obj->relocbase + dynp->d_un.d_ptr); 748 break; 749 750 case DT_PLTRELSZ: 751 obj->pltrelsize = dynp->d_un.d_val; 752 break; 753 754 case DT_RELA: 755 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 756 break; 757 758 case DT_RELASZ: 759 obj->relasize = dynp->d_un.d_val; 760 break; 761 762 case DT_RELAENT: 763 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 764 break; 765 766 case DT_PLTREL: 767 plttype = dynp->d_un.d_val; 768 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 769 break; 770 771 case DT_SYMTAB: 772 obj->symtab = (const Elf_Sym *) 773 (obj->relocbase + dynp->d_un.d_ptr); 774 break; 775 776 case DT_SYMENT: 777 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 778 break; 779 780 case DT_STRTAB: 781 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 782 break; 783 784 case DT_STRSZ: 785 obj->strsize = dynp->d_un.d_val; 786 break; 787 788 case DT_VERNEED: 789 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 790 dynp->d_un.d_val); 791 break; 792 793 case DT_VERNEEDNUM: 794 obj->verneednum = dynp->d_un.d_val; 795 break; 796 797 case DT_VERDEF: 798 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 799 dynp->d_un.d_val); 800 break; 801 802 case DT_VERDEFNUM: 803 obj->verdefnum = dynp->d_un.d_val; 804 break; 805 806 case DT_VERSYM: 807 obj->versyms = (const Elf_Versym *)(obj->relocbase + 808 dynp->d_un.d_val); 809 break; 810 811 case DT_HASH: 812 { 813 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 814 (obj->relocbase + dynp->d_un.d_ptr); 815 obj->nbuckets = hashtab[0]; 816 obj->nchains = hashtab[1]; 817 obj->buckets = hashtab + 2; 818 obj->chains = obj->buckets + obj->nbuckets; 819 } 820 break; 821 822 case DT_NEEDED: 823 if (!obj->rtld) { 824 Needed_Entry *nep = NEW(Needed_Entry); 825 nep->name = dynp->d_un.d_val; 826 nep->obj = NULL; 827 nep->next = NULL; 828 829 *needed_tail = nep; 830 needed_tail = &nep->next; 831 } 832 break; 833 834 case DT_PLTGOT: 835 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 836 break; 837 838 case DT_TEXTREL: 839 obj->textrel = true; 840 break; 841 842 case DT_SYMBOLIC: 843 obj->symbolic = true; 844 break; 845 846 case DT_RPATH: 847 case DT_RUNPATH: /* XXX: process separately */ 848 /* 849 * We have to wait until later to process this, because we 850 * might not have gotten the address of the string table yet. 851 */ 852 *dyn_rpath = dynp; 853 break; 854 855 case DT_SONAME: 856 *dyn_soname = dynp; 857 break; 858 859 case DT_INIT: 860 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 861 break; 862 863 case DT_FINI: 864 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 865 break; 866 867 /* 868 * Don't process DT_DEBUG on MIPS as the dynamic section 869 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 870 */ 871 872 #ifndef __mips__ 873 case DT_DEBUG: 874 /* XXX - not implemented yet */ 875 if (!early) 876 dbg("Filling in DT_DEBUG entry"); 877 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 878 break; 879 #endif 880 881 case DT_FLAGS: 882 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 883 obj->z_origin = true; 884 if (dynp->d_un.d_val & DF_SYMBOLIC) 885 obj->symbolic = true; 886 if (dynp->d_un.d_val & DF_TEXTREL) 887 obj->textrel = true; 888 if (dynp->d_un.d_val & DF_BIND_NOW) 889 obj->bind_now = true; 890 if (dynp->d_un.d_val & DF_STATIC_TLS) 891 ; 892 break; 893 #ifdef __mips__ 894 case DT_MIPS_LOCAL_GOTNO: 895 obj->local_gotno = dynp->d_un.d_val; 896 break; 897 898 case DT_MIPS_SYMTABNO: 899 obj->symtabno = dynp->d_un.d_val; 900 break; 901 902 case DT_MIPS_GOTSYM: 903 obj->gotsym = dynp->d_un.d_val; 904 break; 905 906 case DT_MIPS_RLD_MAP: 907 #ifdef notyet 908 if (!early) 909 dbg("Filling in DT_DEBUG entry"); 910 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 911 #endif 912 break; 913 #endif 914 915 case DT_FLAGS_1: 916 if (dynp->d_un.d_val & DF_1_NOOPEN) 917 obj->z_noopen = true; 918 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 919 obj->z_origin = true; 920 if (dynp->d_un.d_val & DF_1_GLOBAL) 921 /* XXX */; 922 if (dynp->d_un.d_val & DF_1_BIND_NOW) 923 obj->bind_now = true; 924 if (dynp->d_un.d_val & DF_1_NODELETE) 925 obj->z_nodelete = true; 926 break; 927 928 default: 929 if (!early) { 930 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 931 (long)dynp->d_tag); 932 } 933 break; 934 } 935 } 936 937 obj->traced = false; 938 939 if (plttype == DT_RELA) { 940 obj->pltrela = (const Elf_Rela *) obj->pltrel; 941 obj->pltrel = NULL; 942 obj->pltrelasize = obj->pltrelsize; 943 obj->pltrelsize = 0; 944 } 945 } 946 947 static void 948 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 949 const Elf_Dyn *dyn_soname) 950 { 951 952 if (obj->z_origin && obj->origin_path == NULL) { 953 obj->origin_path = xmalloc(PATH_MAX); 954 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 955 die(); 956 } 957 958 if (dyn_rpath != NULL) { 959 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 960 if (obj->z_origin) 961 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 962 } 963 964 if (dyn_soname != NULL) 965 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 966 } 967 968 static void 969 digest_dynamic(Obj_Entry *obj, int early) 970 { 971 const Elf_Dyn *dyn_rpath; 972 const Elf_Dyn *dyn_soname; 973 974 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 975 digest_dynamic2(obj, dyn_rpath, dyn_soname); 976 } 977 978 /* 979 * Process a shared object's program header. This is used only for the 980 * main program, when the kernel has already loaded the main program 981 * into memory before calling the dynamic linker. It creates and 982 * returns an Obj_Entry structure. 983 */ 984 static Obj_Entry * 985 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 986 { 987 Obj_Entry *obj; 988 const Elf_Phdr *phlimit = phdr + phnum; 989 const Elf_Phdr *ph; 990 int nsegs = 0; 991 992 obj = obj_new(); 993 for (ph = phdr; ph < phlimit; ph++) { 994 if (ph->p_type != PT_PHDR) 995 continue; 996 997 obj->phdr = phdr; 998 obj->phsize = ph->p_memsz; 999 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1000 break; 1001 } 1002 1003 for (ph = phdr; ph < phlimit; ph++) { 1004 switch (ph->p_type) { 1005 1006 case PT_INTERP: 1007 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1008 break; 1009 1010 case PT_LOAD: 1011 if (nsegs == 0) { /* First load segment */ 1012 obj->vaddrbase = trunc_page(ph->p_vaddr); 1013 obj->mapbase = obj->vaddrbase + obj->relocbase; 1014 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1015 obj->vaddrbase; 1016 } else { /* Last load segment */ 1017 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1018 obj->vaddrbase; 1019 } 1020 nsegs++; 1021 break; 1022 1023 case PT_DYNAMIC: 1024 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1025 break; 1026 1027 case PT_TLS: 1028 obj->tlsindex = 1; 1029 obj->tlssize = ph->p_memsz; 1030 obj->tlsalign = ph->p_align; 1031 obj->tlsinitsize = ph->p_filesz; 1032 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1033 break; 1034 } 1035 } 1036 if (nsegs < 1) { 1037 _rtld_error("%s: too few PT_LOAD segments", path); 1038 return NULL; 1039 } 1040 1041 obj->entry = entry; 1042 return obj; 1043 } 1044 1045 static Obj_Entry * 1046 dlcheck(void *handle) 1047 { 1048 Obj_Entry *obj; 1049 1050 for (obj = obj_list; obj != NULL; obj = obj->next) 1051 if (obj == (Obj_Entry *) handle) 1052 break; 1053 1054 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1055 _rtld_error("Invalid shared object handle %p", handle); 1056 return NULL; 1057 } 1058 return obj; 1059 } 1060 1061 /* 1062 * If the given object is already in the donelist, return true. Otherwise 1063 * add the object to the list and return false. 1064 */ 1065 static bool 1066 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1067 { 1068 unsigned int i; 1069 1070 for (i = 0; i < dlp->num_used; i++) 1071 if (dlp->objs[i] == obj) 1072 return true; 1073 /* 1074 * Our donelist allocation should always be sufficient. But if 1075 * our threads locking isn't working properly, more shared objects 1076 * could have been loaded since we allocated the list. That should 1077 * never happen, but we'll handle it properly just in case it does. 1078 */ 1079 if (dlp->num_used < dlp->num_alloc) 1080 dlp->objs[dlp->num_used++] = obj; 1081 return false; 1082 } 1083 1084 /* 1085 * Hash function for symbol table lookup. Don't even think about changing 1086 * this. It is specified by the System V ABI. 1087 */ 1088 unsigned long 1089 elf_hash(const char *name) 1090 { 1091 const unsigned char *p = (const unsigned char *) name; 1092 unsigned long h = 0; 1093 unsigned long g; 1094 1095 while (*p != '\0') { 1096 h = (h << 4) + *p++; 1097 if ((g = h & 0xf0000000) != 0) 1098 h ^= g >> 24; 1099 h &= ~g; 1100 } 1101 return h; 1102 } 1103 1104 /* 1105 * Find the library with the given name, and return its full pathname. 1106 * The returned string is dynamically allocated. Generates an error 1107 * message and returns NULL if the library cannot be found. 1108 * 1109 * If the second argument is non-NULL, then it refers to an already- 1110 * loaded shared object, whose library search path will be searched. 1111 * 1112 * The search order is: 1113 * LD_LIBRARY_PATH 1114 * rpath in the referencing file 1115 * ldconfig hints 1116 * /lib:/usr/lib 1117 */ 1118 static char * 1119 find_library(const char *xname, const Obj_Entry *refobj) 1120 { 1121 char *pathname; 1122 char *name; 1123 1124 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1125 if (xname[0] != '/' && !trust) { 1126 _rtld_error("Absolute pathname required for shared object \"%s\"", 1127 xname); 1128 return NULL; 1129 } 1130 if (refobj != NULL && refobj->z_origin) 1131 return origin_subst(xname, refobj->origin_path); 1132 else 1133 return xstrdup(xname); 1134 } 1135 1136 if (libmap_disable || (refobj == NULL) || 1137 (name = lm_find(refobj->path, xname)) == NULL) 1138 name = (char *)xname; 1139 1140 dbg(" Searching for \"%s\"", name); 1141 1142 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1143 (refobj != NULL && 1144 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1145 (pathname = search_library_path(name, gethints())) != NULL || 1146 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1147 return pathname; 1148 1149 if(refobj != NULL && refobj->path != NULL) { 1150 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1151 name, basename(refobj->path)); 1152 } else { 1153 _rtld_error("Shared object \"%s\" not found", name); 1154 } 1155 return NULL; 1156 } 1157 1158 /* 1159 * Given a symbol number in a referencing object, find the corresponding 1160 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1161 * no definition was found. Returns a pointer to the Obj_Entry of the 1162 * defining object via the reference parameter DEFOBJ_OUT. 1163 */ 1164 const Elf_Sym * 1165 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1166 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1167 { 1168 const Elf_Sym *ref; 1169 const Elf_Sym *def; 1170 const Obj_Entry *defobj; 1171 const Ver_Entry *ventry; 1172 const char *name; 1173 unsigned long hash; 1174 1175 /* 1176 * If we have already found this symbol, get the information from 1177 * the cache. 1178 */ 1179 if (symnum >= refobj->nchains) 1180 return NULL; /* Bad object */ 1181 if (cache != NULL && cache[symnum].sym != NULL) { 1182 *defobj_out = cache[symnum].obj; 1183 return cache[symnum].sym; 1184 } 1185 1186 ref = refobj->symtab + symnum; 1187 name = refobj->strtab + ref->st_name; 1188 defobj = NULL; 1189 1190 /* 1191 * We don't have to do a full scale lookup if the symbol is local. 1192 * We know it will bind to the instance in this load module; to 1193 * which we already have a pointer (ie ref). By not doing a lookup, 1194 * we not only improve performance, but it also avoids unresolvable 1195 * symbols when local symbols are not in the hash table. This has 1196 * been seen with the ia64 toolchain. 1197 */ 1198 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1199 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1200 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1201 symnum); 1202 } 1203 ventry = fetch_ventry(refobj, symnum); 1204 hash = elf_hash(name); 1205 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1206 } else { 1207 def = ref; 1208 defobj = refobj; 1209 } 1210 1211 /* 1212 * If we found no definition and the reference is weak, treat the 1213 * symbol as having the value zero. 1214 */ 1215 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1216 def = &sym_zero; 1217 defobj = obj_main; 1218 } 1219 1220 if (def != NULL) { 1221 *defobj_out = defobj; 1222 /* Record the information in the cache to avoid subsequent lookups. */ 1223 if (cache != NULL) { 1224 cache[symnum].sym = def; 1225 cache[symnum].obj = defobj; 1226 } 1227 } else { 1228 if (refobj != &obj_rtld) 1229 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1230 } 1231 return def; 1232 } 1233 1234 /* 1235 * Return the search path from the ldconfig hints file, reading it if 1236 * necessary. Returns NULL if there are problems with the hints file, 1237 * or if the search path there is empty. 1238 */ 1239 static const char * 1240 gethints(void) 1241 { 1242 static char *hints; 1243 1244 if (hints == NULL) { 1245 int fd; 1246 struct elfhints_hdr hdr; 1247 char *p; 1248 1249 /* Keep from trying again in case the hints file is bad. */ 1250 hints = ""; 1251 1252 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1253 return NULL; 1254 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1255 hdr.magic != ELFHINTS_MAGIC || 1256 hdr.version != 1) { 1257 close(fd); 1258 return NULL; 1259 } 1260 p = xmalloc(hdr.dirlistlen + 1); 1261 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1262 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1263 free(p); 1264 close(fd); 1265 return NULL; 1266 } 1267 hints = p; 1268 close(fd); 1269 } 1270 return hints[0] != '\0' ? hints : NULL; 1271 } 1272 1273 static void 1274 init_dag(Obj_Entry *root) 1275 { 1276 DoneList donelist; 1277 1278 donelist_init(&donelist); 1279 init_dag1(root, root, &donelist); 1280 } 1281 1282 static void 1283 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1284 { 1285 const Needed_Entry *needed; 1286 1287 if (donelist_check(dlp, obj)) 1288 return; 1289 1290 obj->refcount++; 1291 objlist_push_tail(&obj->dldags, root); 1292 objlist_push_tail(&root->dagmembers, obj); 1293 for (needed = obj->needed; needed != NULL; needed = needed->next) 1294 if (needed->obj != NULL) 1295 init_dag1(root, needed->obj, dlp); 1296 } 1297 1298 /* 1299 * Initialize the dynamic linker. The argument is the address at which 1300 * the dynamic linker has been mapped into memory. The primary task of 1301 * this function is to relocate the dynamic linker. 1302 */ 1303 static void 1304 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1305 { 1306 Obj_Entry objtmp; /* Temporary rtld object */ 1307 const Elf_Dyn *dyn_rpath; 1308 const Elf_Dyn *dyn_soname; 1309 1310 /* 1311 * Conjure up an Obj_Entry structure for the dynamic linker. 1312 * 1313 * The "path" member can't be initialized yet because string constants 1314 * cannot yet be accessed. Below we will set it correctly. 1315 */ 1316 memset(&objtmp, 0, sizeof(objtmp)); 1317 objtmp.path = NULL; 1318 objtmp.rtld = true; 1319 objtmp.mapbase = mapbase; 1320 #ifdef PIC 1321 objtmp.relocbase = mapbase; 1322 #endif 1323 if (RTLD_IS_DYNAMIC()) { 1324 objtmp.dynamic = rtld_dynamic(&objtmp); 1325 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1326 assert(objtmp.needed == NULL); 1327 #if !defined(__mips__) 1328 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1329 assert(!objtmp.textrel); 1330 #endif 1331 1332 /* 1333 * Temporarily put the dynamic linker entry into the object list, so 1334 * that symbols can be found. 1335 */ 1336 1337 relocate_objects(&objtmp, true, &objtmp); 1338 } 1339 1340 /* Initialize the object list. */ 1341 obj_tail = &obj_list; 1342 1343 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1344 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1345 1346 if (aux_info[AT_PAGESZ] != NULL) 1347 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1348 if (aux_info[AT_OSRELDATE] != NULL) 1349 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1350 1351 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1352 1353 /* Replace the path with a dynamically allocated copy. */ 1354 obj_rtld.path = xstrdup(PATH_RTLD); 1355 1356 r_debug.r_brk = r_debug_state; 1357 r_debug.r_state = RT_CONSISTENT; 1358 } 1359 1360 /* 1361 * Add the init functions from a needed object list (and its recursive 1362 * needed objects) to "list". This is not used directly; it is a helper 1363 * function for initlist_add_objects(). The write lock must be held 1364 * when this function is called. 1365 */ 1366 static void 1367 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1368 { 1369 /* Recursively process the successor needed objects. */ 1370 if (needed->next != NULL) 1371 initlist_add_neededs(needed->next, list); 1372 1373 /* Process the current needed object. */ 1374 if (needed->obj != NULL) 1375 initlist_add_objects(needed->obj, &needed->obj->next, list); 1376 } 1377 1378 /* 1379 * Scan all of the DAGs rooted in the range of objects from "obj" to 1380 * "tail" and add their init functions to "list". This recurses over 1381 * the DAGs and ensure the proper init ordering such that each object's 1382 * needed libraries are initialized before the object itself. At the 1383 * same time, this function adds the objects to the global finalization 1384 * list "list_fini" in the opposite order. The write lock must be 1385 * held when this function is called. 1386 */ 1387 static void 1388 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1389 { 1390 if (obj->init_scanned || obj->init_done) 1391 return; 1392 obj->init_scanned = true; 1393 1394 /* Recursively process the successor objects. */ 1395 if (&obj->next != tail) 1396 initlist_add_objects(obj->next, tail, list); 1397 1398 /* Recursively process the needed objects. */ 1399 if (obj->needed != NULL) 1400 initlist_add_neededs(obj->needed, list); 1401 1402 /* Add the object to the init list. */ 1403 if (obj->init != (Elf_Addr)NULL) 1404 objlist_push_tail(list, obj); 1405 1406 /* Add the object to the global fini list in the reverse order. */ 1407 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1408 objlist_push_head(&list_fini, obj); 1409 obj->on_fini_list = true; 1410 } 1411 } 1412 1413 #ifndef FPTR_TARGET 1414 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1415 #endif 1416 1417 /* 1418 * Given a shared object, traverse its list of needed objects, and load 1419 * each of them. Returns 0 on success. Generates an error message and 1420 * returns -1 on failure. 1421 */ 1422 static int 1423 load_needed_objects(Obj_Entry *first, int flags) 1424 { 1425 Obj_Entry *obj, *obj1; 1426 1427 for (obj = first; obj != NULL; obj = obj->next) { 1428 Needed_Entry *needed; 1429 1430 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1431 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1432 flags & ~RTLD_LO_NOLOAD); 1433 if (obj1 == NULL && !ld_tracing) 1434 return -1; 1435 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1436 dbg("obj %s nodelete", obj1->path); 1437 init_dag(obj1); 1438 ref_dag(obj1); 1439 obj1->ref_nodel = true; 1440 } 1441 } 1442 } 1443 1444 return 0; 1445 } 1446 1447 static int 1448 load_preload_objects(void) 1449 { 1450 char *p = ld_preload; 1451 static const char delim[] = " \t:;"; 1452 1453 if (p == NULL) 1454 return 0; 1455 1456 p += strspn(p, delim); 1457 while (*p != '\0') { 1458 size_t len = strcspn(p, delim); 1459 char savech; 1460 1461 savech = p[len]; 1462 p[len] = '\0'; 1463 if (load_object(p, NULL, 0) == NULL) 1464 return -1; /* XXX - cleanup */ 1465 p[len] = savech; 1466 p += len; 1467 p += strspn(p, delim); 1468 } 1469 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1470 return 0; 1471 } 1472 1473 /* 1474 * Load a shared object into memory, if it is not already loaded. 1475 * 1476 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1477 * on failure. 1478 */ 1479 static Obj_Entry * 1480 load_object(const char *name, const Obj_Entry *refobj, int flags) 1481 { 1482 Obj_Entry *obj; 1483 int fd = -1; 1484 struct stat sb; 1485 char *path; 1486 1487 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1488 if (object_match_name(obj, name)) 1489 return obj; 1490 1491 path = find_library(name, refobj); 1492 if (path == NULL) 1493 return NULL; 1494 1495 /* 1496 * If we didn't find a match by pathname, open the file and check 1497 * again by device and inode. This avoids false mismatches caused 1498 * by multiple links or ".." in pathnames. 1499 * 1500 * To avoid a race, we open the file and use fstat() rather than 1501 * using stat(). 1502 */ 1503 if ((fd = open(path, O_RDONLY)) == -1) { 1504 _rtld_error("Cannot open \"%s\"", path); 1505 free(path); 1506 return NULL; 1507 } 1508 if (fstat(fd, &sb) == -1) { 1509 _rtld_error("Cannot fstat \"%s\"", path); 1510 close(fd); 1511 free(path); 1512 return NULL; 1513 } 1514 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1515 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1516 close(fd); 1517 break; 1518 } 1519 } 1520 if (obj != NULL) { 1521 object_add_name(obj, name); 1522 free(path); 1523 close(fd); 1524 return obj; 1525 } 1526 if (flags & RTLD_LO_NOLOAD) { 1527 free(path); 1528 return (NULL); 1529 } 1530 1531 /* First use of this object, so we must map it in */ 1532 obj = do_load_object(fd, name, path, &sb, flags); 1533 if (obj == NULL) 1534 free(path); 1535 close(fd); 1536 1537 return obj; 1538 } 1539 1540 static Obj_Entry * 1541 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1542 int flags) 1543 { 1544 Obj_Entry *obj; 1545 struct statfs fs; 1546 1547 /* 1548 * but first, make sure that environment variables haven't been 1549 * used to circumvent the noexec flag on a filesystem. 1550 */ 1551 if (dangerous_ld_env) { 1552 if (fstatfs(fd, &fs) != 0) { 1553 _rtld_error("Cannot fstatfs \"%s\"", path); 1554 return NULL; 1555 } 1556 if (fs.f_flags & MNT_NOEXEC) { 1557 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1558 return NULL; 1559 } 1560 } 1561 dbg("loading \"%s\"", path); 1562 obj = map_object(fd, path, sbp); 1563 if (obj == NULL) 1564 return NULL; 1565 1566 object_add_name(obj, name); 1567 obj->path = path; 1568 digest_dynamic(obj, 0); 1569 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1570 RTLD_LO_DLOPEN) { 1571 dbg("refusing to load non-loadable \"%s\"", obj->path); 1572 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1573 munmap(obj->mapbase, obj->mapsize); 1574 obj_free(obj); 1575 return (NULL); 1576 } 1577 1578 *obj_tail = obj; 1579 obj_tail = &obj->next; 1580 obj_count++; 1581 obj_loads++; 1582 linkmap_add(obj); /* for GDB & dlinfo() */ 1583 1584 dbg(" %p .. %p: %s", obj->mapbase, 1585 obj->mapbase + obj->mapsize - 1, obj->path); 1586 if (obj->textrel) 1587 dbg(" WARNING: %s has impure text", obj->path); 1588 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1589 obj->path); 1590 1591 return obj; 1592 } 1593 1594 static Obj_Entry * 1595 obj_from_addr(const void *addr) 1596 { 1597 Obj_Entry *obj; 1598 1599 for (obj = obj_list; obj != NULL; obj = obj->next) { 1600 if (addr < (void *) obj->mapbase) 1601 continue; 1602 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1603 return obj; 1604 } 1605 return NULL; 1606 } 1607 1608 /* 1609 * Call the finalization functions for each of the objects in "list" 1610 * which are unreferenced. All of the objects are expected to have 1611 * non-NULL fini functions. 1612 */ 1613 static void 1614 objlist_call_fini(Objlist *list, bool force, int *lockstate) 1615 { 1616 Objlist_Entry *elm, *elm_tmp; 1617 char *saved_msg; 1618 1619 /* 1620 * Preserve the current error message since a fini function might 1621 * call into the dynamic linker and overwrite it. 1622 */ 1623 saved_msg = errmsg_save(); 1624 STAILQ_FOREACH_SAFE(elm, list, link, elm_tmp) { 1625 if (elm->obj->refcount == 0 || force) { 1626 dbg("calling fini function for %s at %p", elm->obj->path, 1627 (void *)elm->obj->fini); 1628 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1629 elm->obj->path); 1630 /* Remove object from fini list to prevent recursive invocation. */ 1631 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1632 wlock_release(rtld_bind_lock, *lockstate); 1633 call_initfini_pointer(elm->obj, elm->obj->fini); 1634 *lockstate = wlock_acquire(rtld_bind_lock); 1635 /* No need to free anything if process is going down. */ 1636 if (!force) 1637 free(elm); 1638 } 1639 } 1640 errmsg_restore(saved_msg); 1641 } 1642 1643 /* 1644 * Call the initialization functions for each of the objects in 1645 * "list". All of the objects are expected to have non-NULL init 1646 * functions. 1647 */ 1648 static void 1649 objlist_call_init(Objlist *list, int *lockstate) 1650 { 1651 Objlist_Entry *elm; 1652 Obj_Entry *obj; 1653 char *saved_msg; 1654 1655 /* 1656 * Clean init_scanned flag so that objects can be rechecked and 1657 * possibly initialized earlier if any of vectors called below 1658 * cause the change by using dlopen. 1659 */ 1660 for (obj = obj_list; obj != NULL; obj = obj->next) 1661 obj->init_scanned = false; 1662 1663 /* 1664 * Preserve the current error message since an init function might 1665 * call into the dynamic linker and overwrite it. 1666 */ 1667 saved_msg = errmsg_save(); 1668 STAILQ_FOREACH(elm, list, link) { 1669 if (elm->obj->init_done) /* Initialized early. */ 1670 continue; 1671 dbg("calling init function for %s at %p", elm->obj->path, 1672 (void *)elm->obj->init); 1673 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1674 elm->obj->path); 1675 /* 1676 * Race: other thread might try to use this object before current 1677 * one completes the initilization. Not much can be done here 1678 * without better locking. 1679 */ 1680 elm->obj->init_done = true; 1681 wlock_release(rtld_bind_lock, *lockstate); 1682 call_initfini_pointer(elm->obj, elm->obj->init); 1683 *lockstate = wlock_acquire(rtld_bind_lock); 1684 } 1685 errmsg_restore(saved_msg); 1686 } 1687 1688 static void 1689 objlist_clear(Objlist *list) 1690 { 1691 Objlist_Entry *elm; 1692 1693 while (!STAILQ_EMPTY(list)) { 1694 elm = STAILQ_FIRST(list); 1695 STAILQ_REMOVE_HEAD(list, link); 1696 free(elm); 1697 } 1698 } 1699 1700 static Objlist_Entry * 1701 objlist_find(Objlist *list, const Obj_Entry *obj) 1702 { 1703 Objlist_Entry *elm; 1704 1705 STAILQ_FOREACH(elm, list, link) 1706 if (elm->obj == obj) 1707 return elm; 1708 return NULL; 1709 } 1710 1711 static void 1712 objlist_init(Objlist *list) 1713 { 1714 STAILQ_INIT(list); 1715 } 1716 1717 static void 1718 objlist_push_head(Objlist *list, Obj_Entry *obj) 1719 { 1720 Objlist_Entry *elm; 1721 1722 elm = NEW(Objlist_Entry); 1723 elm->obj = obj; 1724 STAILQ_INSERT_HEAD(list, elm, link); 1725 } 1726 1727 static void 1728 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1729 { 1730 Objlist_Entry *elm; 1731 1732 elm = NEW(Objlist_Entry); 1733 elm->obj = obj; 1734 STAILQ_INSERT_TAIL(list, elm, link); 1735 } 1736 1737 static void 1738 objlist_remove(Objlist *list, Obj_Entry *obj) 1739 { 1740 Objlist_Entry *elm; 1741 1742 if ((elm = objlist_find(list, obj)) != NULL) { 1743 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1744 free(elm); 1745 } 1746 } 1747 1748 /* 1749 * Relocate newly-loaded shared objects. The argument is a pointer to 1750 * the Obj_Entry for the first such object. All objects from the first 1751 * to the end of the list of objects are relocated. Returns 0 on success, 1752 * or -1 on failure. 1753 */ 1754 static int 1755 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1756 { 1757 Obj_Entry *obj; 1758 1759 for (obj = first; obj != NULL; obj = obj->next) { 1760 if (obj != rtldobj) 1761 dbg("relocating \"%s\"", obj->path); 1762 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1763 obj->symtab == NULL || obj->strtab == NULL) { 1764 _rtld_error("%s: Shared object has no run-time symbol table", 1765 obj->path); 1766 return -1; 1767 } 1768 1769 if (obj->textrel) { 1770 /* There are relocations to the write-protected text segment. */ 1771 if (mprotect(obj->mapbase, obj->textsize, 1772 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1773 _rtld_error("%s: Cannot write-enable text segment: %s", 1774 obj->path, strerror(errno)); 1775 return -1; 1776 } 1777 } 1778 1779 /* Process the non-PLT relocations. */ 1780 if (reloc_non_plt(obj, rtldobj)) 1781 return -1; 1782 1783 if (obj->textrel) { /* Re-protected the text segment. */ 1784 if (mprotect(obj->mapbase, obj->textsize, 1785 PROT_READ|PROT_EXEC) == -1) { 1786 _rtld_error("%s: Cannot write-protect text segment: %s", 1787 obj->path, strerror(errno)); 1788 return -1; 1789 } 1790 } 1791 1792 /* Process the PLT relocations. */ 1793 if (reloc_plt(obj) == -1) 1794 return -1; 1795 /* Relocate the jump slots if we are doing immediate binding. */ 1796 if (obj->bind_now || bind_now) 1797 if (reloc_jmpslots(obj) == -1) 1798 return -1; 1799 1800 1801 /* 1802 * Set up the magic number and version in the Obj_Entry. These 1803 * were checked in the crt1.o from the original ElfKit, so we 1804 * set them for backward compatibility. 1805 */ 1806 obj->magic = RTLD_MAGIC; 1807 obj->version = RTLD_VERSION; 1808 1809 /* Set the special PLT or GOT entries. */ 1810 init_pltgot(obj); 1811 } 1812 1813 return 0; 1814 } 1815 1816 /* 1817 * Cleanup procedure. It will be called (by the atexit mechanism) just 1818 * before the process exits. 1819 */ 1820 static void 1821 rtld_exit(void) 1822 { 1823 int lockstate; 1824 1825 lockstate = wlock_acquire(rtld_bind_lock); 1826 dbg("rtld_exit()"); 1827 objlist_call_fini(&list_fini, true, &lockstate); 1828 /* No need to remove the items from the list, since we are exiting. */ 1829 if (!libmap_disable) 1830 lm_fini(); 1831 wlock_release(rtld_bind_lock, lockstate); 1832 } 1833 1834 static void * 1835 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1836 { 1837 #ifdef COMPAT_32BIT 1838 const char *trans; 1839 #endif 1840 if (path == NULL) 1841 return (NULL); 1842 1843 path += strspn(path, ":;"); 1844 while (*path != '\0') { 1845 size_t len; 1846 char *res; 1847 1848 len = strcspn(path, ":;"); 1849 #ifdef COMPAT_32BIT 1850 trans = lm_findn(NULL, path, len); 1851 if (trans) 1852 res = callback(trans, strlen(trans), arg); 1853 else 1854 #endif 1855 res = callback(path, len, arg); 1856 1857 if (res != NULL) 1858 return (res); 1859 1860 path += len; 1861 path += strspn(path, ":;"); 1862 } 1863 1864 return (NULL); 1865 } 1866 1867 struct try_library_args { 1868 const char *name; 1869 size_t namelen; 1870 char *buffer; 1871 size_t buflen; 1872 }; 1873 1874 static void * 1875 try_library_path(const char *dir, size_t dirlen, void *param) 1876 { 1877 struct try_library_args *arg; 1878 1879 arg = param; 1880 if (*dir == '/' || trust) { 1881 char *pathname; 1882 1883 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 1884 return (NULL); 1885 1886 pathname = arg->buffer; 1887 strncpy(pathname, dir, dirlen); 1888 pathname[dirlen] = '/'; 1889 strcpy(pathname + dirlen + 1, arg->name); 1890 1891 dbg(" Trying \"%s\"", pathname); 1892 if (access(pathname, F_OK) == 0) { /* We found it */ 1893 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 1894 strcpy(pathname, arg->buffer); 1895 return (pathname); 1896 } 1897 } 1898 return (NULL); 1899 } 1900 1901 static char * 1902 search_library_path(const char *name, const char *path) 1903 { 1904 char *p; 1905 struct try_library_args arg; 1906 1907 if (path == NULL) 1908 return NULL; 1909 1910 arg.name = name; 1911 arg.namelen = strlen(name); 1912 arg.buffer = xmalloc(PATH_MAX); 1913 arg.buflen = PATH_MAX; 1914 1915 p = path_enumerate(path, try_library_path, &arg); 1916 1917 free(arg.buffer); 1918 1919 return (p); 1920 } 1921 1922 int 1923 dlclose(void *handle) 1924 { 1925 Obj_Entry *root; 1926 int lockstate; 1927 1928 lockstate = wlock_acquire(rtld_bind_lock); 1929 root = dlcheck(handle); 1930 if (root == NULL) { 1931 wlock_release(rtld_bind_lock, lockstate); 1932 return -1; 1933 } 1934 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 1935 root->path); 1936 1937 /* Unreference the object and its dependencies. */ 1938 root->dl_refcount--; 1939 1940 unref_dag(root); 1941 1942 if (root->refcount == 0) { 1943 /* 1944 * The object is no longer referenced, so we must unload it. 1945 * First, call the fini functions. 1946 */ 1947 objlist_call_fini(&list_fini, false, &lockstate); 1948 1949 /* Finish cleaning up the newly-unreferenced objects. */ 1950 GDB_STATE(RT_DELETE,&root->linkmap); 1951 unload_object(root); 1952 GDB_STATE(RT_CONSISTENT,NULL); 1953 } 1954 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 1955 wlock_release(rtld_bind_lock, lockstate); 1956 return 0; 1957 } 1958 1959 char * 1960 dlerror(void) 1961 { 1962 char *msg = error_message; 1963 error_message = NULL; 1964 return msg; 1965 } 1966 1967 /* 1968 * This function is deprecated and has no effect. 1969 */ 1970 void 1971 dllockinit(void *context, 1972 void *(*lock_create)(void *context), 1973 void (*rlock_acquire)(void *lock), 1974 void (*wlock_acquire)(void *lock), 1975 void (*lock_release)(void *lock), 1976 void (*lock_destroy)(void *lock), 1977 void (*context_destroy)(void *context)) 1978 { 1979 static void *cur_context; 1980 static void (*cur_context_destroy)(void *); 1981 1982 /* Just destroy the context from the previous call, if necessary. */ 1983 if (cur_context_destroy != NULL) 1984 cur_context_destroy(cur_context); 1985 cur_context = context; 1986 cur_context_destroy = context_destroy; 1987 } 1988 1989 void * 1990 dlopen(const char *name, int mode) 1991 { 1992 Obj_Entry **old_obj_tail; 1993 Obj_Entry *obj; 1994 Objlist initlist; 1995 int result, lockstate, nodelete, lo_flags; 1996 1997 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 1998 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 1999 if (ld_tracing != NULL) 2000 environ = (char **)*get_program_var_addr("environ"); 2001 nodelete = mode & RTLD_NODELETE; 2002 lo_flags = RTLD_LO_DLOPEN; 2003 if (mode & RTLD_NOLOAD) 2004 lo_flags |= RTLD_LO_NOLOAD; 2005 if (ld_tracing != NULL) 2006 lo_flags |= RTLD_LO_TRACE; 2007 2008 objlist_init(&initlist); 2009 2010 lockstate = wlock_acquire(rtld_bind_lock); 2011 GDB_STATE(RT_ADD,NULL); 2012 2013 old_obj_tail = obj_tail; 2014 obj = NULL; 2015 if (name == NULL) { 2016 obj = obj_main; 2017 obj->refcount++; 2018 } else { 2019 obj = load_object(name, obj_main, lo_flags); 2020 } 2021 2022 if (obj) { 2023 obj->dl_refcount++; 2024 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2025 objlist_push_tail(&list_global, obj); 2026 mode &= RTLD_MODEMASK; 2027 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2028 assert(*old_obj_tail == obj); 2029 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2030 init_dag(obj); 2031 if (result != -1) 2032 result = rtld_verify_versions(&obj->dagmembers); 2033 if (result != -1 && ld_tracing) 2034 goto trace; 2035 if (result == -1 || 2036 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2037 obj->dl_refcount--; 2038 unref_dag(obj); 2039 if (obj->refcount == 0) 2040 unload_object(obj); 2041 obj = NULL; 2042 } else { 2043 /* Make list of init functions to call. */ 2044 initlist_add_objects(obj, &obj->next, &initlist); 2045 } 2046 } else { 2047 2048 /* Bump the reference counts for objects on this DAG. */ 2049 ref_dag(obj); 2050 2051 if (ld_tracing) 2052 goto trace; 2053 } 2054 if (obj != NULL && (nodelete || obj->z_nodelete) && !obj->ref_nodel) { 2055 dbg("obj %s nodelete", obj->path); 2056 ref_dag(obj); 2057 obj->z_nodelete = obj->ref_nodel = true; 2058 } 2059 } 2060 2061 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2062 name); 2063 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2064 2065 /* Call the init functions. */ 2066 objlist_call_init(&initlist, &lockstate); 2067 objlist_clear(&initlist); 2068 wlock_release(rtld_bind_lock, lockstate); 2069 return obj; 2070 trace: 2071 trace_loaded_objects(obj); 2072 wlock_release(rtld_bind_lock, lockstate); 2073 exit(0); 2074 } 2075 2076 static void * 2077 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2078 int flags) 2079 { 2080 DoneList donelist; 2081 const Obj_Entry *obj, *defobj; 2082 const Elf_Sym *def, *symp; 2083 unsigned long hash; 2084 int lockstate; 2085 2086 hash = elf_hash(name); 2087 def = NULL; 2088 defobj = NULL; 2089 flags |= SYMLOOK_IN_PLT; 2090 2091 lockstate = rlock_acquire(rtld_bind_lock); 2092 if (handle == NULL || handle == RTLD_NEXT || 2093 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2094 2095 if ((obj = obj_from_addr(retaddr)) == NULL) { 2096 _rtld_error("Cannot determine caller's shared object"); 2097 rlock_release(rtld_bind_lock, lockstate); 2098 return NULL; 2099 } 2100 if (handle == NULL) { /* Just the caller's shared object. */ 2101 def = symlook_obj(name, hash, obj, ve, flags); 2102 defobj = obj; 2103 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2104 handle == RTLD_SELF) { /* ... caller included */ 2105 if (handle == RTLD_NEXT) 2106 obj = obj->next; 2107 for (; obj != NULL; obj = obj->next) { 2108 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2109 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2110 def = symp; 2111 defobj = obj; 2112 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2113 break; 2114 } 2115 } 2116 } 2117 /* 2118 * Search the dynamic linker itself, and possibly resolve the 2119 * symbol from there. This is how the application links to 2120 * dynamic linker services such as dlopen. 2121 */ 2122 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2123 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2124 if (symp != NULL) { 2125 def = symp; 2126 defobj = &obj_rtld; 2127 } 2128 } 2129 } else { 2130 assert(handle == RTLD_DEFAULT); 2131 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2132 } 2133 } else { 2134 if ((obj = dlcheck(handle)) == NULL) { 2135 rlock_release(rtld_bind_lock, lockstate); 2136 return NULL; 2137 } 2138 2139 donelist_init(&donelist); 2140 if (obj->mainprog) { 2141 /* Search main program and all libraries loaded by it. */ 2142 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2143 &donelist); 2144 2145 /* 2146 * We do not distinguish between 'main' object and global scope. 2147 * If symbol is not defined by objects loaded at startup, continue 2148 * search among dynamically loaded objects with RTLD_GLOBAL 2149 * scope. 2150 */ 2151 if (def == NULL) 2152 def = symlook_list(name, hash, &list_global, &defobj, ve, 2153 flags, &donelist); 2154 } else { 2155 Needed_Entry fake; 2156 2157 /* Search the whole DAG rooted at the given object. */ 2158 fake.next = NULL; 2159 fake.obj = (Obj_Entry *)obj; 2160 fake.name = 0; 2161 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2162 &donelist); 2163 } 2164 } 2165 2166 if (def != NULL) { 2167 rlock_release(rtld_bind_lock, lockstate); 2168 2169 /* 2170 * The value required by the caller is derived from the value 2171 * of the symbol. For the ia64 architecture, we need to 2172 * construct a function descriptor which the caller can use to 2173 * call the function with the right 'gp' value. For other 2174 * architectures and for non-functions, the value is simply 2175 * the relocated value of the symbol. 2176 */ 2177 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2178 return make_function_pointer(def, defobj); 2179 else 2180 return defobj->relocbase + def->st_value; 2181 } 2182 2183 _rtld_error("Undefined symbol \"%s\"", name); 2184 rlock_release(rtld_bind_lock, lockstate); 2185 return NULL; 2186 } 2187 2188 void * 2189 dlsym(void *handle, const char *name) 2190 { 2191 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2192 SYMLOOK_DLSYM); 2193 } 2194 2195 dlfunc_t 2196 dlfunc(void *handle, const char *name) 2197 { 2198 union { 2199 void *d; 2200 dlfunc_t f; 2201 } rv; 2202 2203 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2204 SYMLOOK_DLSYM); 2205 return (rv.f); 2206 } 2207 2208 void * 2209 dlvsym(void *handle, const char *name, const char *version) 2210 { 2211 Ver_Entry ventry; 2212 2213 ventry.name = version; 2214 ventry.file = NULL; 2215 ventry.hash = elf_hash(version); 2216 ventry.flags= 0; 2217 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2218 SYMLOOK_DLSYM); 2219 } 2220 2221 int 2222 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2223 { 2224 const Obj_Entry *obj; 2225 int lockstate; 2226 2227 lockstate = rlock_acquire(rtld_bind_lock); 2228 obj = obj_from_addr(addr); 2229 if (obj == NULL) { 2230 _rtld_error("No shared object contains address"); 2231 rlock_release(rtld_bind_lock, lockstate); 2232 return (0); 2233 } 2234 rtld_fill_dl_phdr_info(obj, phdr_info); 2235 rlock_release(rtld_bind_lock, lockstate); 2236 return (1); 2237 } 2238 2239 int 2240 dladdr(const void *addr, Dl_info *info) 2241 { 2242 const Obj_Entry *obj; 2243 const Elf_Sym *def; 2244 void *symbol_addr; 2245 unsigned long symoffset; 2246 int lockstate; 2247 2248 lockstate = rlock_acquire(rtld_bind_lock); 2249 obj = obj_from_addr(addr); 2250 if (obj == NULL) { 2251 _rtld_error("No shared object contains address"); 2252 rlock_release(rtld_bind_lock, lockstate); 2253 return 0; 2254 } 2255 info->dli_fname = obj->path; 2256 info->dli_fbase = obj->mapbase; 2257 info->dli_saddr = (void *)0; 2258 info->dli_sname = NULL; 2259 2260 /* 2261 * Walk the symbol list looking for the symbol whose address is 2262 * closest to the address sent in. 2263 */ 2264 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2265 def = obj->symtab + symoffset; 2266 2267 /* 2268 * For skip the symbol if st_shndx is either SHN_UNDEF or 2269 * SHN_COMMON. 2270 */ 2271 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2272 continue; 2273 2274 /* 2275 * If the symbol is greater than the specified address, or if it 2276 * is further away from addr than the current nearest symbol, 2277 * then reject it. 2278 */ 2279 symbol_addr = obj->relocbase + def->st_value; 2280 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2281 continue; 2282 2283 /* Update our idea of the nearest symbol. */ 2284 info->dli_sname = obj->strtab + def->st_name; 2285 info->dli_saddr = symbol_addr; 2286 2287 /* Exact match? */ 2288 if (info->dli_saddr == addr) 2289 break; 2290 } 2291 rlock_release(rtld_bind_lock, lockstate); 2292 return 1; 2293 } 2294 2295 int 2296 dlinfo(void *handle, int request, void *p) 2297 { 2298 const Obj_Entry *obj; 2299 int error, lockstate; 2300 2301 lockstate = rlock_acquire(rtld_bind_lock); 2302 2303 if (handle == NULL || handle == RTLD_SELF) { 2304 void *retaddr; 2305 2306 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2307 if ((obj = obj_from_addr(retaddr)) == NULL) 2308 _rtld_error("Cannot determine caller's shared object"); 2309 } else 2310 obj = dlcheck(handle); 2311 2312 if (obj == NULL) { 2313 rlock_release(rtld_bind_lock, lockstate); 2314 return (-1); 2315 } 2316 2317 error = 0; 2318 switch (request) { 2319 case RTLD_DI_LINKMAP: 2320 *((struct link_map const **)p) = &obj->linkmap; 2321 break; 2322 case RTLD_DI_ORIGIN: 2323 error = rtld_dirname(obj->path, p); 2324 break; 2325 2326 case RTLD_DI_SERINFOSIZE: 2327 case RTLD_DI_SERINFO: 2328 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2329 break; 2330 2331 default: 2332 _rtld_error("Invalid request %d passed to dlinfo()", request); 2333 error = -1; 2334 } 2335 2336 rlock_release(rtld_bind_lock, lockstate); 2337 2338 return (error); 2339 } 2340 2341 static void 2342 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2343 { 2344 2345 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2346 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2347 STAILQ_FIRST(&obj->names)->name : obj->path; 2348 phdr_info->dlpi_phdr = obj->phdr; 2349 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2350 phdr_info->dlpi_tls_modid = obj->tlsindex; 2351 phdr_info->dlpi_tls_data = obj->tlsinit; 2352 phdr_info->dlpi_adds = obj_loads; 2353 phdr_info->dlpi_subs = obj_loads - obj_count; 2354 } 2355 2356 int 2357 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2358 { 2359 struct dl_phdr_info phdr_info; 2360 const Obj_Entry *obj; 2361 int error, bind_lockstate, phdr_lockstate; 2362 2363 phdr_lockstate = wlock_acquire(rtld_phdr_lock); 2364 bind_lockstate = rlock_acquire(rtld_bind_lock); 2365 2366 error = 0; 2367 2368 for (obj = obj_list; obj != NULL; obj = obj->next) { 2369 rtld_fill_dl_phdr_info(obj, &phdr_info); 2370 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2371 break; 2372 2373 } 2374 rlock_release(rtld_bind_lock, bind_lockstate); 2375 wlock_release(rtld_phdr_lock, phdr_lockstate); 2376 2377 return (error); 2378 } 2379 2380 struct fill_search_info_args { 2381 int request; 2382 unsigned int flags; 2383 Dl_serinfo *serinfo; 2384 Dl_serpath *serpath; 2385 char *strspace; 2386 }; 2387 2388 static void * 2389 fill_search_info(const char *dir, size_t dirlen, void *param) 2390 { 2391 struct fill_search_info_args *arg; 2392 2393 arg = param; 2394 2395 if (arg->request == RTLD_DI_SERINFOSIZE) { 2396 arg->serinfo->dls_cnt ++; 2397 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2398 } else { 2399 struct dl_serpath *s_entry; 2400 2401 s_entry = arg->serpath; 2402 s_entry->dls_name = arg->strspace; 2403 s_entry->dls_flags = arg->flags; 2404 2405 strncpy(arg->strspace, dir, dirlen); 2406 arg->strspace[dirlen] = '\0'; 2407 2408 arg->strspace += dirlen + 1; 2409 arg->serpath++; 2410 } 2411 2412 return (NULL); 2413 } 2414 2415 static int 2416 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2417 { 2418 struct dl_serinfo _info; 2419 struct fill_search_info_args args; 2420 2421 args.request = RTLD_DI_SERINFOSIZE; 2422 args.serinfo = &_info; 2423 2424 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2425 _info.dls_cnt = 0; 2426 2427 path_enumerate(ld_library_path, fill_search_info, &args); 2428 path_enumerate(obj->rpath, fill_search_info, &args); 2429 path_enumerate(gethints(), fill_search_info, &args); 2430 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2431 2432 2433 if (request == RTLD_DI_SERINFOSIZE) { 2434 info->dls_size = _info.dls_size; 2435 info->dls_cnt = _info.dls_cnt; 2436 return (0); 2437 } 2438 2439 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2440 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2441 return (-1); 2442 } 2443 2444 args.request = RTLD_DI_SERINFO; 2445 args.serinfo = info; 2446 args.serpath = &info->dls_serpath[0]; 2447 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2448 2449 args.flags = LA_SER_LIBPATH; 2450 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2451 return (-1); 2452 2453 args.flags = LA_SER_RUNPATH; 2454 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2455 return (-1); 2456 2457 args.flags = LA_SER_CONFIG; 2458 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2459 return (-1); 2460 2461 args.flags = LA_SER_DEFAULT; 2462 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2463 return (-1); 2464 return (0); 2465 } 2466 2467 static int 2468 rtld_dirname(const char *path, char *bname) 2469 { 2470 const char *endp; 2471 2472 /* Empty or NULL string gets treated as "." */ 2473 if (path == NULL || *path == '\0') { 2474 bname[0] = '.'; 2475 bname[1] = '\0'; 2476 return (0); 2477 } 2478 2479 /* Strip trailing slashes */ 2480 endp = path + strlen(path) - 1; 2481 while (endp > path && *endp == '/') 2482 endp--; 2483 2484 /* Find the start of the dir */ 2485 while (endp > path && *endp != '/') 2486 endp--; 2487 2488 /* Either the dir is "/" or there are no slashes */ 2489 if (endp == path) { 2490 bname[0] = *endp == '/' ? '/' : '.'; 2491 bname[1] = '\0'; 2492 return (0); 2493 } else { 2494 do { 2495 endp--; 2496 } while (endp > path && *endp == '/'); 2497 } 2498 2499 if (endp - path + 2 > PATH_MAX) 2500 { 2501 _rtld_error("Filename is too long: %s", path); 2502 return(-1); 2503 } 2504 2505 strncpy(bname, path, endp - path + 1); 2506 bname[endp - path + 1] = '\0'; 2507 return (0); 2508 } 2509 2510 static int 2511 rtld_dirname_abs(const char *path, char *base) 2512 { 2513 char base_rel[PATH_MAX]; 2514 2515 if (rtld_dirname(path, base) == -1) 2516 return (-1); 2517 if (base[0] == '/') 2518 return (0); 2519 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2520 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2521 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2522 return (-1); 2523 strcpy(base, base_rel); 2524 return (0); 2525 } 2526 2527 static void 2528 linkmap_add(Obj_Entry *obj) 2529 { 2530 struct link_map *l = &obj->linkmap; 2531 struct link_map *prev; 2532 2533 obj->linkmap.l_name = obj->path; 2534 obj->linkmap.l_addr = obj->mapbase; 2535 obj->linkmap.l_ld = obj->dynamic; 2536 #ifdef __mips__ 2537 /* GDB needs load offset on MIPS to use the symbols */ 2538 obj->linkmap.l_offs = obj->relocbase; 2539 #endif 2540 2541 if (r_debug.r_map == NULL) { 2542 r_debug.r_map = l; 2543 return; 2544 } 2545 2546 /* 2547 * Scan to the end of the list, but not past the entry for the 2548 * dynamic linker, which we want to keep at the very end. 2549 */ 2550 for (prev = r_debug.r_map; 2551 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2552 prev = prev->l_next) 2553 ; 2554 2555 /* Link in the new entry. */ 2556 l->l_prev = prev; 2557 l->l_next = prev->l_next; 2558 if (l->l_next != NULL) 2559 l->l_next->l_prev = l; 2560 prev->l_next = l; 2561 } 2562 2563 static void 2564 linkmap_delete(Obj_Entry *obj) 2565 { 2566 struct link_map *l = &obj->linkmap; 2567 2568 if (l->l_prev == NULL) { 2569 if ((r_debug.r_map = l->l_next) != NULL) 2570 l->l_next->l_prev = NULL; 2571 return; 2572 } 2573 2574 if ((l->l_prev->l_next = l->l_next) != NULL) 2575 l->l_next->l_prev = l->l_prev; 2576 } 2577 2578 /* 2579 * Function for the debugger to set a breakpoint on to gain control. 2580 * 2581 * The two parameters allow the debugger to easily find and determine 2582 * what the runtime loader is doing and to whom it is doing it. 2583 * 2584 * When the loadhook trap is hit (r_debug_state, set at program 2585 * initialization), the arguments can be found on the stack: 2586 * 2587 * +8 struct link_map *m 2588 * +4 struct r_debug *rd 2589 * +0 RetAddr 2590 */ 2591 void 2592 r_debug_state(struct r_debug* rd, struct link_map *m) 2593 { 2594 } 2595 2596 /* 2597 * Get address of the pointer variable in the main program. 2598 */ 2599 static const void ** 2600 get_program_var_addr(const char *name) 2601 { 2602 const Obj_Entry *obj; 2603 unsigned long hash; 2604 2605 hash = elf_hash(name); 2606 for (obj = obj_main; obj != NULL; obj = obj->next) { 2607 const Elf_Sym *def; 2608 2609 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2610 const void **addr; 2611 2612 addr = (const void **)(obj->relocbase + def->st_value); 2613 return addr; 2614 } 2615 } 2616 return NULL; 2617 } 2618 2619 /* 2620 * Set a pointer variable in the main program to the given value. This 2621 * is used to set key variables such as "environ" before any of the 2622 * init functions are called. 2623 */ 2624 static void 2625 set_program_var(const char *name, const void *value) 2626 { 2627 const void **addr; 2628 2629 if ((addr = get_program_var_addr(name)) != NULL) { 2630 dbg("\"%s\": *%p <-- %p", name, addr, value); 2631 *addr = value; 2632 } 2633 } 2634 2635 /* 2636 * Given a symbol name in a referencing object, find the corresponding 2637 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2638 * no definition was found. Returns a pointer to the Obj_Entry of the 2639 * defining object via the reference parameter DEFOBJ_OUT. 2640 */ 2641 static const Elf_Sym * 2642 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2643 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2644 { 2645 DoneList donelist; 2646 const Elf_Sym *def; 2647 const Elf_Sym *symp; 2648 const Obj_Entry *obj; 2649 const Obj_Entry *defobj; 2650 const Objlist_Entry *elm; 2651 def = NULL; 2652 defobj = NULL; 2653 donelist_init(&donelist); 2654 2655 /* Look first in the referencing object if linked symbolically. */ 2656 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2657 symp = symlook_obj(name, hash, refobj, ventry, flags); 2658 if (symp != NULL) { 2659 def = symp; 2660 defobj = refobj; 2661 } 2662 } 2663 2664 /* Search all objects loaded at program start up. */ 2665 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2666 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2667 &donelist); 2668 if (symp != NULL && 2669 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2670 def = symp; 2671 defobj = obj; 2672 } 2673 } 2674 2675 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2676 STAILQ_FOREACH(elm, &list_global, link) { 2677 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2678 break; 2679 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2680 flags, &donelist); 2681 if (symp != NULL && 2682 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2683 def = symp; 2684 defobj = obj; 2685 } 2686 } 2687 2688 /* Search all dlopened DAGs containing the referencing object. */ 2689 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2690 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2691 break; 2692 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2693 flags, &donelist); 2694 if (symp != NULL && 2695 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2696 def = symp; 2697 defobj = obj; 2698 } 2699 } 2700 2701 /* 2702 * Search the dynamic linker itself, and possibly resolve the 2703 * symbol from there. This is how the application links to 2704 * dynamic linker services such as dlopen. 2705 */ 2706 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2707 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2708 if (symp != NULL) { 2709 def = symp; 2710 defobj = &obj_rtld; 2711 } 2712 } 2713 2714 if (def != NULL) 2715 *defobj_out = defobj; 2716 return def; 2717 } 2718 2719 static const Elf_Sym * 2720 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2721 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2722 DoneList *dlp) 2723 { 2724 const Elf_Sym *symp; 2725 const Elf_Sym *def; 2726 const Obj_Entry *defobj; 2727 const Objlist_Entry *elm; 2728 2729 def = NULL; 2730 defobj = NULL; 2731 STAILQ_FOREACH(elm, objlist, link) { 2732 if (donelist_check(dlp, elm->obj)) 2733 continue; 2734 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2735 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2736 def = symp; 2737 defobj = elm->obj; 2738 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2739 break; 2740 } 2741 } 2742 } 2743 if (def != NULL) 2744 *defobj_out = defobj; 2745 return def; 2746 } 2747 2748 /* 2749 * Search the symbol table of a shared object and all objects needed 2750 * by it for a symbol of the given name. Search order is 2751 * breadth-first. Returns a pointer to the symbol, or NULL if no 2752 * definition was found. 2753 */ 2754 static const Elf_Sym * 2755 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2756 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2757 DoneList *dlp) 2758 { 2759 const Elf_Sym *def, *def_w; 2760 const Needed_Entry *n; 2761 const Obj_Entry *obj, *defobj, *defobj1; 2762 2763 def = def_w = NULL; 2764 defobj = NULL; 2765 for (n = needed; n != NULL; n = n->next) { 2766 if ((obj = n->obj) == NULL || 2767 donelist_check(dlp, obj) || 2768 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2769 continue; 2770 defobj = obj; 2771 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2772 *defobj_out = defobj; 2773 return (def); 2774 } 2775 } 2776 /* 2777 * There we come when either symbol definition is not found in 2778 * directly needed objects, or found symbol is weak. 2779 */ 2780 for (n = needed; n != NULL; n = n->next) { 2781 if ((obj = n->obj) == NULL) 2782 continue; 2783 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2784 ventry, flags, dlp); 2785 if (def_w == NULL) 2786 continue; 2787 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2788 def = def_w; 2789 defobj = defobj1; 2790 } 2791 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2792 break; 2793 } 2794 if (def != NULL) 2795 *defobj_out = defobj; 2796 return (def); 2797 } 2798 2799 /* 2800 * Search the symbol table of a single shared object for a symbol of 2801 * the given name and version, if requested. Returns a pointer to the 2802 * symbol, or NULL if no definition was found. 2803 * 2804 * The symbol's hash value is passed in for efficiency reasons; that 2805 * eliminates many recomputations of the hash value. 2806 */ 2807 const Elf_Sym * 2808 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2809 const Ver_Entry *ventry, int flags) 2810 { 2811 unsigned long symnum; 2812 const Elf_Sym *vsymp; 2813 Elf_Versym verndx; 2814 int vcount; 2815 2816 if (obj->buckets == NULL) 2817 return NULL; 2818 2819 vsymp = NULL; 2820 vcount = 0; 2821 symnum = obj->buckets[hash % obj->nbuckets]; 2822 2823 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2824 const Elf_Sym *symp; 2825 const char *strp; 2826 2827 if (symnum >= obj->nchains) 2828 return NULL; /* Bad object */ 2829 2830 symp = obj->symtab + symnum; 2831 strp = obj->strtab + symp->st_name; 2832 2833 switch (ELF_ST_TYPE(symp->st_info)) { 2834 case STT_FUNC: 2835 case STT_NOTYPE: 2836 case STT_OBJECT: 2837 if (symp->st_value == 0) 2838 continue; 2839 /* fallthrough */ 2840 case STT_TLS: 2841 if (symp->st_shndx != SHN_UNDEF) 2842 break; 2843 #ifndef __mips__ 2844 else if (((flags & SYMLOOK_IN_PLT) == 0) && 2845 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 2846 break; 2847 /* fallthrough */ 2848 #endif 2849 default: 2850 continue; 2851 } 2852 if (name[0] != strp[0] || strcmp(name, strp) != 0) 2853 continue; 2854 2855 if (ventry == NULL) { 2856 if (obj->versyms != NULL) { 2857 verndx = VER_NDX(obj->versyms[symnum]); 2858 if (verndx > obj->vernum) { 2859 _rtld_error("%s: symbol %s references wrong version %d", 2860 obj->path, obj->strtab + symnum, verndx); 2861 continue; 2862 } 2863 /* 2864 * If we are not called from dlsym (i.e. this is a normal 2865 * relocation from unversioned binary, accept the symbol 2866 * immediately if it happens to have first version after 2867 * this shared object became versioned. Otherwise, if 2868 * symbol is versioned and not hidden, remember it. If it 2869 * is the only symbol with this name exported by the 2870 * shared object, it will be returned as a match at the 2871 * end of the function. If symbol is global (verndx < 2) 2872 * accept it unconditionally. 2873 */ 2874 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 2875 return symp; 2876 else if (verndx >= VER_NDX_GIVEN) { 2877 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 2878 if (vsymp == NULL) 2879 vsymp = symp; 2880 vcount ++; 2881 } 2882 continue; 2883 } 2884 } 2885 return symp; 2886 } else { 2887 if (obj->versyms == NULL) { 2888 if (object_match_name(obj, ventry->name)) { 2889 _rtld_error("%s: object %s should provide version %s for " 2890 "symbol %s", obj_rtld.path, obj->path, ventry->name, 2891 obj->strtab + symnum); 2892 continue; 2893 } 2894 } else { 2895 verndx = VER_NDX(obj->versyms[symnum]); 2896 if (verndx > obj->vernum) { 2897 _rtld_error("%s: symbol %s references wrong version %d", 2898 obj->path, obj->strtab + symnum, verndx); 2899 continue; 2900 } 2901 if (obj->vertab[verndx].hash != ventry->hash || 2902 strcmp(obj->vertab[verndx].name, ventry->name)) { 2903 /* 2904 * Version does not match. Look if this is a global symbol 2905 * and if it is not hidden. If global symbol (verndx < 2) 2906 * is available, use it. Do not return symbol if we are 2907 * called by dlvsym, because dlvsym looks for a specific 2908 * version and default one is not what dlvsym wants. 2909 */ 2910 if ((flags & SYMLOOK_DLSYM) || 2911 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 2912 (verndx >= VER_NDX_GIVEN)) 2913 continue; 2914 } 2915 } 2916 return symp; 2917 } 2918 } 2919 return (vcount == 1) ? vsymp : NULL; 2920 } 2921 2922 static void 2923 trace_loaded_objects(Obj_Entry *obj) 2924 { 2925 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 2926 int c; 2927 2928 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 2929 main_local = ""; 2930 2931 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 2932 fmt1 = "\t%o => %p (%x)\n"; 2933 2934 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 2935 fmt2 = "\t%o (%x)\n"; 2936 2937 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 2938 2939 for (; obj; obj = obj->next) { 2940 Needed_Entry *needed; 2941 char *name, *path; 2942 bool is_lib; 2943 2944 if (list_containers && obj->needed != NULL) 2945 printf("%s:\n", obj->path); 2946 for (needed = obj->needed; needed; needed = needed->next) { 2947 if (needed->obj != NULL) { 2948 if (needed->obj->traced && !list_containers) 2949 continue; 2950 needed->obj->traced = true; 2951 path = needed->obj->path; 2952 } else 2953 path = "not found"; 2954 2955 name = (char *)obj->strtab + needed->name; 2956 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 2957 2958 fmt = is_lib ? fmt1 : fmt2; 2959 while ((c = *fmt++) != '\0') { 2960 switch (c) { 2961 default: 2962 putchar(c); 2963 continue; 2964 case '\\': 2965 switch (c = *fmt) { 2966 case '\0': 2967 continue; 2968 case 'n': 2969 putchar('\n'); 2970 break; 2971 case 't': 2972 putchar('\t'); 2973 break; 2974 } 2975 break; 2976 case '%': 2977 switch (c = *fmt) { 2978 case '\0': 2979 continue; 2980 case '%': 2981 default: 2982 putchar(c); 2983 break; 2984 case 'A': 2985 printf("%s", main_local); 2986 break; 2987 case 'a': 2988 printf("%s", obj_main->path); 2989 break; 2990 case 'o': 2991 printf("%s", name); 2992 break; 2993 #if 0 2994 case 'm': 2995 printf("%d", sodp->sod_major); 2996 break; 2997 case 'n': 2998 printf("%d", sodp->sod_minor); 2999 break; 3000 #endif 3001 case 'p': 3002 printf("%s", path); 3003 break; 3004 case 'x': 3005 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3006 break; 3007 } 3008 break; 3009 } 3010 ++fmt; 3011 } 3012 } 3013 } 3014 } 3015 3016 /* 3017 * Unload a dlopened object and its dependencies from memory and from 3018 * our data structures. It is assumed that the DAG rooted in the 3019 * object has already been unreferenced, and that the object has a 3020 * reference count of 0. 3021 */ 3022 static void 3023 unload_object(Obj_Entry *root) 3024 { 3025 Obj_Entry *obj; 3026 Obj_Entry **linkp; 3027 3028 assert(root->refcount == 0); 3029 3030 /* 3031 * Pass over the DAG removing unreferenced objects from 3032 * appropriate lists. 3033 */ 3034 unlink_object(root); 3035 3036 /* Unmap all objects that are no longer referenced. */ 3037 linkp = &obj_list->next; 3038 while ((obj = *linkp) != NULL) { 3039 if (obj->refcount == 0) { 3040 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3041 obj->path); 3042 dbg("unloading \"%s\"", obj->path); 3043 munmap(obj->mapbase, obj->mapsize); 3044 linkmap_delete(obj); 3045 *linkp = obj->next; 3046 obj_count--; 3047 obj_free(obj); 3048 } else 3049 linkp = &obj->next; 3050 } 3051 obj_tail = linkp; 3052 } 3053 3054 static void 3055 unlink_object(Obj_Entry *root) 3056 { 3057 Objlist_Entry *elm; 3058 3059 if (root->refcount == 0) { 3060 /* Remove the object from the RTLD_GLOBAL list. */ 3061 objlist_remove(&list_global, root); 3062 3063 /* Remove the object from all objects' DAG lists. */ 3064 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3065 objlist_remove(&elm->obj->dldags, root); 3066 if (elm->obj != root) 3067 unlink_object(elm->obj); 3068 } 3069 } 3070 } 3071 3072 static void 3073 ref_dag(Obj_Entry *root) 3074 { 3075 Objlist_Entry *elm; 3076 3077 STAILQ_FOREACH(elm, &root->dagmembers, link) 3078 elm->obj->refcount++; 3079 } 3080 3081 static void 3082 unref_dag(Obj_Entry *root) 3083 { 3084 Objlist_Entry *elm; 3085 3086 STAILQ_FOREACH(elm, &root->dagmembers, link) 3087 elm->obj->refcount--; 3088 } 3089 3090 /* 3091 * Common code for MD __tls_get_addr(). 3092 */ 3093 void * 3094 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3095 { 3096 Elf_Addr* dtv = *dtvp; 3097 int lockstate; 3098 3099 /* Check dtv generation in case new modules have arrived */ 3100 if (dtv[0] != tls_dtv_generation) { 3101 Elf_Addr* newdtv; 3102 int to_copy; 3103 3104 lockstate = wlock_acquire(rtld_bind_lock); 3105 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3106 to_copy = dtv[1]; 3107 if (to_copy > tls_max_index) 3108 to_copy = tls_max_index; 3109 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3110 newdtv[0] = tls_dtv_generation; 3111 newdtv[1] = tls_max_index; 3112 free(dtv); 3113 wlock_release(rtld_bind_lock, lockstate); 3114 *dtvp = newdtv; 3115 } 3116 3117 /* Dynamically allocate module TLS if necessary */ 3118 if (!dtv[index + 1]) { 3119 /* Signal safe, wlock will block out signals. */ 3120 lockstate = wlock_acquire(rtld_bind_lock); 3121 if (!dtv[index + 1]) 3122 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3123 wlock_release(rtld_bind_lock, lockstate); 3124 } 3125 return (void*) (dtv[index + 1] + offset); 3126 } 3127 3128 /* XXX not sure what variants to use for arm. */ 3129 3130 #if defined(__ia64__) || defined(__powerpc__) 3131 3132 /* 3133 * Allocate Static TLS using the Variant I method. 3134 */ 3135 void * 3136 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3137 { 3138 Obj_Entry *obj; 3139 char *tcb; 3140 Elf_Addr **tls; 3141 Elf_Addr *dtv; 3142 Elf_Addr addr; 3143 int i; 3144 3145 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3146 return (oldtcb); 3147 3148 assert(tcbsize >= TLS_TCB_SIZE); 3149 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3150 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3151 3152 if (oldtcb != NULL) { 3153 memcpy(tls, oldtcb, tls_static_space); 3154 free(oldtcb); 3155 3156 /* Adjust the DTV. */ 3157 dtv = tls[0]; 3158 for (i = 0; i < dtv[1]; i++) { 3159 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3160 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3161 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3162 } 3163 } 3164 } else { 3165 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3166 tls[0] = dtv; 3167 dtv[0] = tls_dtv_generation; 3168 dtv[1] = tls_max_index; 3169 3170 for (obj = objs; obj; obj = obj->next) { 3171 if (obj->tlsoffset > 0) { 3172 addr = (Elf_Addr)tls + obj->tlsoffset; 3173 if (obj->tlsinitsize > 0) 3174 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3175 if (obj->tlssize > obj->tlsinitsize) 3176 memset((void*) (addr + obj->tlsinitsize), 0, 3177 obj->tlssize - obj->tlsinitsize); 3178 dtv[obj->tlsindex + 1] = addr; 3179 } 3180 } 3181 } 3182 3183 return (tcb); 3184 } 3185 3186 void 3187 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3188 { 3189 Elf_Addr *dtv; 3190 Elf_Addr tlsstart, tlsend; 3191 int dtvsize, i; 3192 3193 assert(tcbsize >= TLS_TCB_SIZE); 3194 3195 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3196 tlsend = tlsstart + tls_static_space; 3197 3198 dtv = *(Elf_Addr **)tlsstart; 3199 dtvsize = dtv[1]; 3200 for (i = 0; i < dtvsize; i++) { 3201 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3202 free((void*)dtv[i+2]); 3203 } 3204 } 3205 free(dtv); 3206 free(tcb); 3207 } 3208 3209 #endif 3210 3211 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3212 defined(__arm__) || defined(__mips__) 3213 3214 /* 3215 * Allocate Static TLS using the Variant II method. 3216 */ 3217 void * 3218 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3219 { 3220 Obj_Entry *obj; 3221 size_t size; 3222 char *tls; 3223 Elf_Addr *dtv, *olddtv; 3224 Elf_Addr segbase, oldsegbase, addr; 3225 int i; 3226 3227 size = round(tls_static_space, tcbalign); 3228 3229 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3230 tls = calloc(1, size + tcbsize); 3231 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3232 3233 segbase = (Elf_Addr)(tls + size); 3234 ((Elf_Addr*)segbase)[0] = segbase; 3235 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3236 3237 dtv[0] = tls_dtv_generation; 3238 dtv[1] = tls_max_index; 3239 3240 if (oldtls) { 3241 /* 3242 * Copy the static TLS block over whole. 3243 */ 3244 oldsegbase = (Elf_Addr) oldtls; 3245 memcpy((void *)(segbase - tls_static_space), 3246 (const void *)(oldsegbase - tls_static_space), 3247 tls_static_space); 3248 3249 /* 3250 * If any dynamic TLS blocks have been created tls_get_addr(), 3251 * move them over. 3252 */ 3253 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3254 for (i = 0; i < olddtv[1]; i++) { 3255 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3256 dtv[i+2] = olddtv[i+2]; 3257 olddtv[i+2] = 0; 3258 } 3259 } 3260 3261 /* 3262 * We assume that this block was the one we created with 3263 * allocate_initial_tls(). 3264 */ 3265 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3266 } else { 3267 for (obj = objs; obj; obj = obj->next) { 3268 if (obj->tlsoffset) { 3269 addr = segbase - obj->tlsoffset; 3270 memset((void*) (addr + obj->tlsinitsize), 3271 0, obj->tlssize - obj->tlsinitsize); 3272 if (obj->tlsinit) 3273 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3274 dtv[obj->tlsindex + 1] = addr; 3275 } 3276 } 3277 } 3278 3279 return (void*) segbase; 3280 } 3281 3282 void 3283 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3284 { 3285 size_t size; 3286 Elf_Addr* dtv; 3287 int dtvsize, i; 3288 Elf_Addr tlsstart, tlsend; 3289 3290 /* 3291 * Figure out the size of the initial TLS block so that we can 3292 * find stuff which ___tls_get_addr() allocated dynamically. 3293 */ 3294 size = round(tls_static_space, tcbalign); 3295 3296 dtv = ((Elf_Addr**)tls)[1]; 3297 dtvsize = dtv[1]; 3298 tlsend = (Elf_Addr) tls; 3299 tlsstart = tlsend - size; 3300 for (i = 0; i < dtvsize; i++) { 3301 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3302 free((void*) dtv[i+2]); 3303 } 3304 } 3305 3306 free((void*) tlsstart); 3307 free((void*) dtv); 3308 } 3309 3310 #endif 3311 3312 /* 3313 * Allocate TLS block for module with given index. 3314 */ 3315 void * 3316 allocate_module_tls(int index) 3317 { 3318 Obj_Entry* obj; 3319 char* p; 3320 3321 for (obj = obj_list; obj; obj = obj->next) { 3322 if (obj->tlsindex == index) 3323 break; 3324 } 3325 if (!obj) { 3326 _rtld_error("Can't find module with TLS index %d", index); 3327 die(); 3328 } 3329 3330 p = malloc(obj->tlssize); 3331 if (p == NULL) { 3332 _rtld_error("Cannot allocate TLS block for index %d", index); 3333 die(); 3334 } 3335 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3336 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3337 3338 return p; 3339 } 3340 3341 bool 3342 allocate_tls_offset(Obj_Entry *obj) 3343 { 3344 size_t off; 3345 3346 if (obj->tls_done) 3347 return true; 3348 3349 if (obj->tlssize == 0) { 3350 obj->tls_done = true; 3351 return true; 3352 } 3353 3354 if (obj->tlsindex == 1) 3355 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3356 else 3357 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3358 obj->tlssize, obj->tlsalign); 3359 3360 /* 3361 * If we have already fixed the size of the static TLS block, we 3362 * must stay within that size. When allocating the static TLS, we 3363 * leave a small amount of space spare to be used for dynamically 3364 * loading modules which use static TLS. 3365 */ 3366 if (tls_static_space) { 3367 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3368 return false; 3369 } 3370 3371 tls_last_offset = obj->tlsoffset = off; 3372 tls_last_size = obj->tlssize; 3373 obj->tls_done = true; 3374 3375 return true; 3376 } 3377 3378 void 3379 free_tls_offset(Obj_Entry *obj) 3380 { 3381 3382 /* 3383 * If we were the last thing to allocate out of the static TLS 3384 * block, we give our space back to the 'allocator'. This is a 3385 * simplistic workaround to allow libGL.so.1 to be loaded and 3386 * unloaded multiple times. 3387 */ 3388 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3389 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3390 tls_last_offset -= obj->tlssize; 3391 tls_last_size = 0; 3392 } 3393 } 3394 3395 void * 3396 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3397 { 3398 void *ret; 3399 int lockstate; 3400 3401 lockstate = wlock_acquire(rtld_bind_lock); 3402 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3403 wlock_release(rtld_bind_lock, lockstate); 3404 return (ret); 3405 } 3406 3407 void 3408 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3409 { 3410 int lockstate; 3411 3412 lockstate = wlock_acquire(rtld_bind_lock); 3413 free_tls(tcb, tcbsize, tcbalign); 3414 wlock_release(rtld_bind_lock, lockstate); 3415 } 3416 3417 static void 3418 object_add_name(Obj_Entry *obj, const char *name) 3419 { 3420 Name_Entry *entry; 3421 size_t len; 3422 3423 len = strlen(name); 3424 entry = malloc(sizeof(Name_Entry) + len); 3425 3426 if (entry != NULL) { 3427 strcpy(entry->name, name); 3428 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3429 } 3430 } 3431 3432 static int 3433 object_match_name(const Obj_Entry *obj, const char *name) 3434 { 3435 Name_Entry *entry; 3436 3437 STAILQ_FOREACH(entry, &obj->names, link) { 3438 if (strcmp(name, entry->name) == 0) 3439 return (1); 3440 } 3441 return (0); 3442 } 3443 3444 static Obj_Entry * 3445 locate_dependency(const Obj_Entry *obj, const char *name) 3446 { 3447 const Objlist_Entry *entry; 3448 const Needed_Entry *needed; 3449 3450 STAILQ_FOREACH(entry, &list_main, link) { 3451 if (object_match_name(entry->obj, name)) 3452 return entry->obj; 3453 } 3454 3455 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3456 if (needed->obj == NULL) 3457 continue; 3458 if (object_match_name(needed->obj, name)) 3459 return needed->obj; 3460 } 3461 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3462 obj->path, name); 3463 die(); 3464 } 3465 3466 static int 3467 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3468 const Elf_Vernaux *vna) 3469 { 3470 const Elf_Verdef *vd; 3471 const char *vername; 3472 3473 vername = refobj->strtab + vna->vna_name; 3474 vd = depobj->verdef; 3475 if (vd == NULL) { 3476 _rtld_error("%s: version %s required by %s not defined", 3477 depobj->path, vername, refobj->path); 3478 return (-1); 3479 } 3480 for (;;) { 3481 if (vd->vd_version != VER_DEF_CURRENT) { 3482 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3483 depobj->path, vd->vd_version); 3484 return (-1); 3485 } 3486 if (vna->vna_hash == vd->vd_hash) { 3487 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3488 ((char *)vd + vd->vd_aux); 3489 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3490 return (0); 3491 } 3492 if (vd->vd_next == 0) 3493 break; 3494 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3495 } 3496 if (vna->vna_flags & VER_FLG_WEAK) 3497 return (0); 3498 _rtld_error("%s: version %s required by %s not found", 3499 depobj->path, vername, refobj->path); 3500 return (-1); 3501 } 3502 3503 static int 3504 rtld_verify_object_versions(Obj_Entry *obj) 3505 { 3506 const Elf_Verneed *vn; 3507 const Elf_Verdef *vd; 3508 const Elf_Verdaux *vda; 3509 const Elf_Vernaux *vna; 3510 const Obj_Entry *depobj; 3511 int maxvernum, vernum; 3512 3513 maxvernum = 0; 3514 /* 3515 * Walk over defined and required version records and figure out 3516 * max index used by any of them. Do very basic sanity checking 3517 * while there. 3518 */ 3519 vn = obj->verneed; 3520 while (vn != NULL) { 3521 if (vn->vn_version != VER_NEED_CURRENT) { 3522 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3523 obj->path, vn->vn_version); 3524 return (-1); 3525 } 3526 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3527 for (;;) { 3528 vernum = VER_NEED_IDX(vna->vna_other); 3529 if (vernum > maxvernum) 3530 maxvernum = vernum; 3531 if (vna->vna_next == 0) 3532 break; 3533 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3534 } 3535 if (vn->vn_next == 0) 3536 break; 3537 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3538 } 3539 3540 vd = obj->verdef; 3541 while (vd != NULL) { 3542 if (vd->vd_version != VER_DEF_CURRENT) { 3543 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3544 obj->path, vd->vd_version); 3545 return (-1); 3546 } 3547 vernum = VER_DEF_IDX(vd->vd_ndx); 3548 if (vernum > maxvernum) 3549 maxvernum = vernum; 3550 if (vd->vd_next == 0) 3551 break; 3552 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3553 } 3554 3555 if (maxvernum == 0) 3556 return (0); 3557 3558 /* 3559 * Store version information in array indexable by version index. 3560 * Verify that object version requirements are satisfied along the 3561 * way. 3562 */ 3563 obj->vernum = maxvernum + 1; 3564 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3565 3566 vd = obj->verdef; 3567 while (vd != NULL) { 3568 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3569 vernum = VER_DEF_IDX(vd->vd_ndx); 3570 assert(vernum <= maxvernum); 3571 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3572 obj->vertab[vernum].hash = vd->vd_hash; 3573 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3574 obj->vertab[vernum].file = NULL; 3575 obj->vertab[vernum].flags = 0; 3576 } 3577 if (vd->vd_next == 0) 3578 break; 3579 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3580 } 3581 3582 vn = obj->verneed; 3583 while (vn != NULL) { 3584 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3585 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3586 for (;;) { 3587 if (check_object_provided_version(obj, depobj, vna)) 3588 return (-1); 3589 vernum = VER_NEED_IDX(vna->vna_other); 3590 assert(vernum <= maxvernum); 3591 obj->vertab[vernum].hash = vna->vna_hash; 3592 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3593 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3594 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3595 VER_INFO_HIDDEN : 0; 3596 if (vna->vna_next == 0) 3597 break; 3598 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3599 } 3600 if (vn->vn_next == 0) 3601 break; 3602 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3603 } 3604 return 0; 3605 } 3606 3607 static int 3608 rtld_verify_versions(const Objlist *objlist) 3609 { 3610 Objlist_Entry *entry; 3611 int rc; 3612 3613 rc = 0; 3614 STAILQ_FOREACH(entry, objlist, link) { 3615 /* 3616 * Skip dummy objects or objects that have their version requirements 3617 * already checked. 3618 */ 3619 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3620 continue; 3621 if (rtld_verify_object_versions(entry->obj) == -1) { 3622 rc = -1; 3623 if (ld_tracing == NULL) 3624 break; 3625 } 3626 } 3627 if (rc == 0 || ld_tracing != NULL) 3628 rc = rtld_verify_object_versions(&obj_rtld); 3629 return rc; 3630 } 3631 3632 const Ver_Entry * 3633 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3634 { 3635 Elf_Versym vernum; 3636 3637 if (obj->vertab) { 3638 vernum = VER_NDX(obj->versyms[symnum]); 3639 if (vernum >= obj->vernum) { 3640 _rtld_error("%s: symbol %s has wrong verneed value %d", 3641 obj->path, obj->strtab + symnum, vernum); 3642 } else if (obj->vertab[vernum].hash != 0) { 3643 return &obj->vertab[vernum]; 3644 } 3645 } 3646 return NULL; 3647 } 3648 3649 /* 3650 * Overrides for libc_pic-provided functions. 3651 */ 3652 3653 int 3654 __getosreldate(void) 3655 { 3656 size_t len; 3657 int oid[2]; 3658 int error, osrel; 3659 3660 if (osreldate != 0) 3661 return (osreldate); 3662 3663 oid[0] = CTL_KERN; 3664 oid[1] = KERN_OSRELDATE; 3665 osrel = 0; 3666 len = sizeof(osrel); 3667 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 3668 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 3669 osreldate = osrel; 3670 return (osreldate); 3671 } 3672 3673 /* 3674 * No unresolved symbols for rtld. 3675 */ 3676 void 3677 __pthread_cxa_finalize(struct dl_phdr_info *a) 3678 { 3679 } 3680