1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mount.h> 42 #include <sys/mman.h> 43 #include <sys/stat.h> 44 #include <sys/sysctl.h> 45 #include <sys/uio.h> 46 #include <sys/utsname.h> 47 #include <sys/ktrace.h> 48 49 #include <dlfcn.h> 50 #include <err.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 #include "debug.h" 60 #include "rtld.h" 61 #include "libmap.h" 62 #include "rtld_tls.h" 63 64 #ifndef COMPAT_32BIT 65 #define PATH_RTLD "/libexec/ld-elf.so.1" 66 #else 67 #define PATH_RTLD "/libexec/ld-elf32.so.1" 68 #endif 69 70 /* Types. */ 71 typedef void (*func_ptr_type)(); 72 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 73 74 /* 75 * Function declarations. 76 */ 77 static const char *basename(const char *); 78 static void die(void) __dead2; 79 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 80 const Elf_Dyn **); 81 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 82 static void digest_dynamic(Obj_Entry *, int); 83 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 84 static Obj_Entry *dlcheck(void *); 85 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj, 86 int lo_flags, int mode); 87 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 88 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 89 static bool donelist_check(DoneList *, const Obj_Entry *); 90 static void errmsg_restore(char *); 91 static char *errmsg_save(void); 92 static void *fill_search_info(const char *, size_t, void *); 93 static char *find_library(const char *, const Obj_Entry *); 94 static const char *gethints(void); 95 static void init_dag(Obj_Entry *); 96 static void init_rtld(caddr_t, Elf_Auxinfo **); 97 static void initlist_add_neededs(Needed_Entry *, Objlist *); 98 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 99 static void linkmap_add(Obj_Entry *); 100 static void linkmap_delete(Obj_Entry *); 101 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 102 static void unload_filtees(Obj_Entry *); 103 static int load_needed_objects(Obj_Entry *, int); 104 static int load_preload_objects(void); 105 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 106 static void map_stacks_exec(RtldLockState *); 107 static Obj_Entry *obj_from_addr(const void *); 108 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 109 static void objlist_call_init(Objlist *, RtldLockState *); 110 static void objlist_clear(Objlist *); 111 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 112 static void objlist_init(Objlist *); 113 static void objlist_push_head(Objlist *, Obj_Entry *); 114 static void objlist_push_tail(Objlist *, Obj_Entry *); 115 static void objlist_remove(Objlist *, Obj_Entry *); 116 static void *path_enumerate(const char *, path_enum_proc, void *); 117 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *); 118 static int rtld_dirname(const char *, char *); 119 static int rtld_dirname_abs(const char *, char *); 120 static void rtld_exit(void); 121 static char *search_library_path(const char *, const char *); 122 static const void **get_program_var_addr(const char *, RtldLockState *); 123 static void set_program_var(const char *, const void *); 124 static int symlook_default(SymLook *, const Obj_Entry *refobj); 125 static int symlook_global(SymLook *, DoneList *); 126 static void symlook_init_from_req(SymLook *, const SymLook *); 127 static int symlook_list(SymLook *, const Objlist *, DoneList *); 128 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 129 static int symlook_obj1(SymLook *, const Obj_Entry *); 130 static void trace_loaded_objects(Obj_Entry *); 131 static void unlink_object(Obj_Entry *); 132 static void unload_object(Obj_Entry *); 133 static void unref_dag(Obj_Entry *); 134 static void ref_dag(Obj_Entry *); 135 static int origin_subst_one(char **, const char *, const char *, 136 const char *, char *); 137 static char *origin_subst(const char *, const char *); 138 static int rtld_verify_versions(const Objlist *); 139 static int rtld_verify_object_versions(Obj_Entry *); 140 static void object_add_name(Obj_Entry *, const char *); 141 static int object_match_name(const Obj_Entry *, const char *); 142 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 143 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 144 struct dl_phdr_info *phdr_info); 145 146 void r_debug_state(struct r_debug *, struct link_map *); 147 148 /* 149 * Data declarations. 150 */ 151 static char *error_message; /* Message for dlerror(), or NULL */ 152 struct r_debug r_debug; /* for GDB; */ 153 static bool libmap_disable; /* Disable libmap */ 154 static bool ld_loadfltr; /* Immediate filters processing */ 155 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 156 static bool trust; /* False for setuid and setgid programs */ 157 static bool dangerous_ld_env; /* True if environment variables have been 158 used to affect the libraries loaded */ 159 static char *ld_bind_now; /* Environment variable for immediate binding */ 160 static char *ld_debug; /* Environment variable for debugging */ 161 static char *ld_library_path; /* Environment variable for search path */ 162 static char *ld_preload; /* Environment variable for libraries to 163 load first */ 164 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 165 static char *ld_tracing; /* Called from ldd to print libs */ 166 static char *ld_utrace; /* Use utrace() to log events. */ 167 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 168 static Obj_Entry **obj_tail; /* Link field of last object in list */ 169 static Obj_Entry *obj_main; /* The main program shared object */ 170 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 171 static unsigned int obj_count; /* Number of objects in obj_list */ 172 static unsigned int obj_loads; /* Number of objects in obj_list */ 173 174 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 175 STAILQ_HEAD_INITIALIZER(list_global); 176 static Objlist list_main = /* Objects loaded at program startup */ 177 STAILQ_HEAD_INITIALIZER(list_main); 178 static Objlist list_fini = /* Objects needing fini() calls */ 179 STAILQ_HEAD_INITIALIZER(list_fini); 180 181 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 182 183 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 184 185 extern Elf_Dyn _DYNAMIC; 186 #pragma weak _DYNAMIC 187 #ifndef RTLD_IS_DYNAMIC 188 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 189 #endif 190 191 int osreldate, pagesize; 192 193 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 194 static int max_stack_flags; 195 196 /* 197 * Global declarations normally provided by crt1. The dynamic linker is 198 * not built with crt1, so we have to provide them ourselves. 199 */ 200 char *__progname; 201 char **environ; 202 203 /* 204 * Globals to control TLS allocation. 205 */ 206 size_t tls_last_offset; /* Static TLS offset of last module */ 207 size_t tls_last_size; /* Static TLS size of last module */ 208 size_t tls_static_space; /* Static TLS space allocated */ 209 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 210 int tls_max_index = 1; /* Largest module index allocated */ 211 212 /* 213 * Fill in a DoneList with an allocation large enough to hold all of 214 * the currently-loaded objects. Keep this as a macro since it calls 215 * alloca and we want that to occur within the scope of the caller. 216 */ 217 #define donelist_init(dlp) \ 218 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 219 assert((dlp)->objs != NULL), \ 220 (dlp)->num_alloc = obj_count, \ 221 (dlp)->num_used = 0) 222 223 #define UTRACE_DLOPEN_START 1 224 #define UTRACE_DLOPEN_STOP 2 225 #define UTRACE_DLCLOSE_START 3 226 #define UTRACE_DLCLOSE_STOP 4 227 #define UTRACE_LOAD_OBJECT 5 228 #define UTRACE_UNLOAD_OBJECT 6 229 #define UTRACE_ADD_RUNDEP 7 230 #define UTRACE_PRELOAD_FINISHED 8 231 #define UTRACE_INIT_CALL 9 232 #define UTRACE_FINI_CALL 10 233 234 struct utrace_rtld { 235 char sig[4]; /* 'RTLD' */ 236 int event; 237 void *handle; 238 void *mapbase; /* Used for 'parent' and 'init/fini' */ 239 size_t mapsize; 240 int refcnt; /* Used for 'mode' */ 241 char name[MAXPATHLEN]; 242 }; 243 244 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 245 if (ld_utrace != NULL) \ 246 ld_utrace_log(e, h, mb, ms, r, n); \ 247 } while (0) 248 249 static void 250 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 251 int refcnt, const char *name) 252 { 253 struct utrace_rtld ut; 254 255 ut.sig[0] = 'R'; 256 ut.sig[1] = 'T'; 257 ut.sig[2] = 'L'; 258 ut.sig[3] = 'D'; 259 ut.event = event; 260 ut.handle = handle; 261 ut.mapbase = mapbase; 262 ut.mapsize = mapsize; 263 ut.refcnt = refcnt; 264 bzero(ut.name, sizeof(ut.name)); 265 if (name) 266 strlcpy(ut.name, name, sizeof(ut.name)); 267 utrace(&ut, sizeof(ut)); 268 } 269 270 /* 271 * Main entry point for dynamic linking. The first argument is the 272 * stack pointer. The stack is expected to be laid out as described 273 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 274 * Specifically, the stack pointer points to a word containing 275 * ARGC. Following that in the stack is a null-terminated sequence 276 * of pointers to argument strings. Then comes a null-terminated 277 * sequence of pointers to environment strings. Finally, there is a 278 * sequence of "auxiliary vector" entries. 279 * 280 * The second argument points to a place to store the dynamic linker's 281 * exit procedure pointer and the third to a place to store the main 282 * program's object. 283 * 284 * The return value is the main program's entry point. 285 */ 286 func_ptr_type 287 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 288 { 289 Elf_Auxinfo *aux_info[AT_COUNT]; 290 int i; 291 int argc; 292 char **argv; 293 char **env; 294 Elf_Auxinfo *aux; 295 Elf_Auxinfo *auxp; 296 const char *argv0; 297 Objlist_Entry *entry; 298 Obj_Entry *obj; 299 Obj_Entry **preload_tail; 300 Objlist initlist; 301 RtldLockState lockstate; 302 303 /* 304 * On entry, the dynamic linker itself has not been relocated yet. 305 * Be very careful not to reference any global data until after 306 * init_rtld has returned. It is OK to reference file-scope statics 307 * and string constants, and to call static and global functions. 308 */ 309 310 /* Find the auxiliary vector on the stack. */ 311 argc = *sp++; 312 argv = (char **) sp; 313 sp += argc + 1; /* Skip over arguments and NULL terminator */ 314 env = (char **) sp; 315 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 316 ; 317 aux = (Elf_Auxinfo *) sp; 318 319 /* Digest the auxiliary vector. */ 320 for (i = 0; i < AT_COUNT; i++) 321 aux_info[i] = NULL; 322 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 323 if (auxp->a_type < AT_COUNT) 324 aux_info[auxp->a_type] = auxp; 325 } 326 327 /* Initialize and relocate ourselves. */ 328 assert(aux_info[AT_BASE] != NULL); 329 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 330 331 __progname = obj_rtld.path; 332 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 333 environ = env; 334 335 trust = !issetugid(); 336 337 ld_bind_now = getenv(LD_ "BIND_NOW"); 338 /* 339 * If the process is tainted, then we un-set the dangerous environment 340 * variables. The process will be marked as tainted until setuid(2) 341 * is called. If any child process calls setuid(2) we do not want any 342 * future processes to honor the potentially un-safe variables. 343 */ 344 if (!trust) { 345 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 346 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 347 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 348 unsetenv(LD_ "LOADFLTR")) { 349 _rtld_error("environment corrupt; aborting"); 350 die(); 351 } 352 } 353 ld_debug = getenv(LD_ "DEBUG"); 354 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 355 libmap_override = getenv(LD_ "LIBMAP"); 356 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 357 ld_preload = getenv(LD_ "PRELOAD"); 358 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 359 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 360 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 361 (ld_library_path != NULL) || (ld_preload != NULL) || 362 (ld_elf_hints_path != NULL) || ld_loadfltr; 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 dbg("initializing thread locks"); 377 lockdflt_init(); 378 379 /* 380 * Load the main program, or process its program header if it is 381 * already loaded. 382 */ 383 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 384 int fd = aux_info[AT_EXECFD]->a_un.a_val; 385 dbg("loading main program"); 386 obj_main = map_object(fd, argv0, NULL); 387 close(fd); 388 if (obj_main == NULL) 389 die(); 390 max_stack_flags = obj->stack_flags; 391 } else { /* Main program already loaded. */ 392 const Elf_Phdr *phdr; 393 int phnum; 394 caddr_t entry; 395 396 dbg("processing main program's program header"); 397 assert(aux_info[AT_PHDR] != NULL); 398 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 399 assert(aux_info[AT_PHNUM] != NULL); 400 phnum = aux_info[AT_PHNUM]->a_un.a_val; 401 assert(aux_info[AT_PHENT] != NULL); 402 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 403 assert(aux_info[AT_ENTRY] != NULL); 404 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 405 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 406 die(); 407 } 408 409 if (aux_info[AT_EXECPATH] != 0) { 410 char *kexecpath; 411 char buf[MAXPATHLEN]; 412 413 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 414 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 415 if (kexecpath[0] == '/') 416 obj_main->path = kexecpath; 417 else if (getcwd(buf, sizeof(buf)) == NULL || 418 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 419 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 420 obj_main->path = xstrdup(argv0); 421 else 422 obj_main->path = xstrdup(buf); 423 } else { 424 dbg("No AT_EXECPATH"); 425 obj_main->path = xstrdup(argv0); 426 } 427 dbg("obj_main path %s", obj_main->path); 428 obj_main->mainprog = true; 429 430 if (aux_info[AT_STACKPROT] != NULL && 431 aux_info[AT_STACKPROT]->a_un.a_val != 0) 432 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 433 434 /* 435 * Get the actual dynamic linker pathname from the executable if 436 * possible. (It should always be possible.) That ensures that 437 * gdb will find the right dynamic linker even if a non-standard 438 * one is being used. 439 */ 440 if (obj_main->interp != NULL && 441 strcmp(obj_main->interp, obj_rtld.path) != 0) { 442 free(obj_rtld.path); 443 obj_rtld.path = xstrdup(obj_main->interp); 444 __progname = obj_rtld.path; 445 } 446 447 digest_dynamic(obj_main, 0); 448 449 linkmap_add(obj_main); 450 linkmap_add(&obj_rtld); 451 452 /* Link the main program into the list of objects. */ 453 *obj_tail = obj_main; 454 obj_tail = &obj_main->next; 455 obj_count++; 456 obj_loads++; 457 /* Make sure we don't call the main program's init and fini functions. */ 458 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 459 460 /* Initialize a fake symbol for resolving undefined weak references. */ 461 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 462 sym_zero.st_shndx = SHN_UNDEF; 463 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 464 465 if (!libmap_disable) 466 libmap_disable = (bool)lm_init(libmap_override); 467 468 dbg("loading LD_PRELOAD libraries"); 469 if (load_preload_objects() == -1) 470 die(); 471 preload_tail = obj_tail; 472 473 dbg("loading needed objects"); 474 if (load_needed_objects(obj_main, 0) == -1) 475 die(); 476 477 /* Make a list of all objects loaded at startup. */ 478 for (obj = obj_list; obj != NULL; obj = obj->next) { 479 objlist_push_tail(&list_main, obj); 480 obj->refcount++; 481 } 482 483 dbg("checking for required versions"); 484 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 485 die(); 486 487 if (ld_tracing) { /* We're done */ 488 trace_loaded_objects(obj_main); 489 exit(0); 490 } 491 492 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 493 dump_relocations(obj_main); 494 exit (0); 495 } 496 497 /* setup TLS for main thread */ 498 dbg("initializing initial thread local storage"); 499 STAILQ_FOREACH(entry, &list_main, link) { 500 /* 501 * Allocate all the initial objects out of the static TLS 502 * block even if they didn't ask for it. 503 */ 504 allocate_tls_offset(entry->obj); 505 } 506 allocate_initial_tls(obj_list); 507 508 if (relocate_objects(obj_main, 509 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1) 510 die(); 511 512 dbg("doing copy relocations"); 513 if (do_copy_relocations(obj_main) == -1) 514 die(); 515 516 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 517 dump_relocations(obj_main); 518 exit (0); 519 } 520 521 dbg("initializing key program variables"); 522 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 523 set_program_var("environ", env); 524 set_program_var("__elf_aux_vector", aux); 525 526 /* Make a list of init functions to call. */ 527 objlist_init(&initlist); 528 initlist_add_objects(obj_list, preload_tail, &initlist); 529 530 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 531 532 map_stacks_exec(NULL); 533 534 wlock_acquire(rtld_bind_lock, &lockstate); 535 objlist_call_init(&initlist, &lockstate); 536 objlist_clear(&initlist); 537 dbg("loading filtees"); 538 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 539 if (ld_loadfltr || obj->z_loadfltr) 540 load_filtees(obj, 0, &lockstate); 541 } 542 lock_release(rtld_bind_lock, &lockstate); 543 544 dbg("transferring control to program entry point = %p", obj_main->entry); 545 546 /* Return the exit procedure and the program entry point. */ 547 *exit_proc = rtld_exit; 548 *objp = obj_main; 549 return (func_ptr_type) obj_main->entry; 550 } 551 552 Elf_Addr 553 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 554 { 555 const Elf_Rel *rel; 556 const Elf_Sym *def; 557 const Obj_Entry *defobj; 558 Elf_Addr *where; 559 Elf_Addr target; 560 RtldLockState lockstate; 561 562 rlock_acquire(rtld_bind_lock, &lockstate); 563 if (sigsetjmp(lockstate.env, 0) != 0) 564 lock_upgrade(rtld_bind_lock, &lockstate); 565 if (obj->pltrel) 566 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 567 else 568 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 569 570 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 571 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 572 &lockstate); 573 if (def == NULL) 574 die(); 575 576 target = (Elf_Addr)(defobj->relocbase + def->st_value); 577 578 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 579 defobj->strtab + def->st_name, basename(obj->path), 580 (void *)target, basename(defobj->path)); 581 582 /* 583 * Write the new contents for the jmpslot. Note that depending on 584 * architecture, the value which we need to return back to the 585 * lazy binding trampoline may or may not be the target 586 * address. The value returned from reloc_jmpslot() is the value 587 * that the trampoline needs. 588 */ 589 target = reloc_jmpslot(where, target, defobj, obj, rel); 590 lock_release(rtld_bind_lock, &lockstate); 591 return target; 592 } 593 594 /* 595 * Error reporting function. Use it like printf. If formats the message 596 * into a buffer, and sets things up so that the next call to dlerror() 597 * will return the message. 598 */ 599 void 600 _rtld_error(const char *fmt, ...) 601 { 602 static char buf[512]; 603 va_list ap; 604 605 va_start(ap, fmt); 606 vsnprintf(buf, sizeof buf, fmt, ap); 607 error_message = buf; 608 va_end(ap); 609 } 610 611 /* 612 * Return a dynamically-allocated copy of the current error message, if any. 613 */ 614 static char * 615 errmsg_save(void) 616 { 617 return error_message == NULL ? NULL : xstrdup(error_message); 618 } 619 620 /* 621 * Restore the current error message from a copy which was previously saved 622 * by errmsg_save(). The copy is freed. 623 */ 624 static void 625 errmsg_restore(char *saved_msg) 626 { 627 if (saved_msg == NULL) 628 error_message = NULL; 629 else { 630 _rtld_error("%s", saved_msg); 631 free(saved_msg); 632 } 633 } 634 635 static const char * 636 basename(const char *name) 637 { 638 const char *p = strrchr(name, '/'); 639 return p != NULL ? p + 1 : name; 640 } 641 642 static struct utsname uts; 643 644 static int 645 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 646 char *may_free) 647 { 648 const char *p, *p1; 649 char *res1; 650 int subst_len; 651 int kw_len; 652 653 res1 = *res = NULL; 654 p = real; 655 subst_len = kw_len = 0; 656 for (;;) { 657 p1 = strstr(p, kw); 658 if (p1 != NULL) { 659 if (subst_len == 0) { 660 subst_len = strlen(subst); 661 kw_len = strlen(kw); 662 } 663 if (*res == NULL) { 664 *res = xmalloc(PATH_MAX); 665 res1 = *res; 666 } 667 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 668 _rtld_error("Substitution of %s in %s cannot be performed", 669 kw, real); 670 if (may_free != NULL) 671 free(may_free); 672 free(res); 673 return (false); 674 } 675 memcpy(res1, p, p1 - p); 676 res1 += p1 - p; 677 memcpy(res1, subst, subst_len); 678 res1 += subst_len; 679 p = p1 + kw_len; 680 } else { 681 if (*res == NULL) { 682 if (may_free != NULL) 683 *res = may_free; 684 else 685 *res = xstrdup(real); 686 return (true); 687 } 688 *res1 = '\0'; 689 if (may_free != NULL) 690 free(may_free); 691 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 692 free(res); 693 return (false); 694 } 695 return (true); 696 } 697 } 698 } 699 700 static char * 701 origin_subst(const char *real, const char *origin_path) 702 { 703 char *res1, *res2, *res3, *res4; 704 705 if (uts.sysname[0] == '\0') { 706 if (uname(&uts) != 0) { 707 _rtld_error("utsname failed: %d", errno); 708 return (NULL); 709 } 710 } 711 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 712 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 713 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 714 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 715 return (NULL); 716 return (res4); 717 } 718 719 static void 720 die(void) 721 { 722 const char *msg = dlerror(); 723 724 if (msg == NULL) 725 msg = "Fatal error"; 726 errx(1, "%s", msg); 727 } 728 729 /* 730 * Process a shared object's DYNAMIC section, and save the important 731 * information in its Obj_Entry structure. 732 */ 733 static void 734 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 735 const Elf_Dyn **dyn_soname) 736 { 737 const Elf_Dyn *dynp; 738 Needed_Entry **needed_tail = &obj->needed; 739 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 740 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 741 int plttype = DT_REL; 742 743 *dyn_rpath = NULL; 744 *dyn_soname = NULL; 745 746 obj->bind_now = false; 747 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 748 switch (dynp->d_tag) { 749 750 case DT_REL: 751 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 752 break; 753 754 case DT_RELSZ: 755 obj->relsize = dynp->d_un.d_val; 756 break; 757 758 case DT_RELENT: 759 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 760 break; 761 762 case DT_JMPREL: 763 obj->pltrel = (const Elf_Rel *) 764 (obj->relocbase + dynp->d_un.d_ptr); 765 break; 766 767 case DT_PLTRELSZ: 768 obj->pltrelsize = dynp->d_un.d_val; 769 break; 770 771 case DT_RELA: 772 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 773 break; 774 775 case DT_RELASZ: 776 obj->relasize = dynp->d_un.d_val; 777 break; 778 779 case DT_RELAENT: 780 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 781 break; 782 783 case DT_PLTREL: 784 plttype = dynp->d_un.d_val; 785 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 786 break; 787 788 case DT_SYMTAB: 789 obj->symtab = (const Elf_Sym *) 790 (obj->relocbase + dynp->d_un.d_ptr); 791 break; 792 793 case DT_SYMENT: 794 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 795 break; 796 797 case DT_STRTAB: 798 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 799 break; 800 801 case DT_STRSZ: 802 obj->strsize = dynp->d_un.d_val; 803 break; 804 805 case DT_VERNEED: 806 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 807 dynp->d_un.d_val); 808 break; 809 810 case DT_VERNEEDNUM: 811 obj->verneednum = dynp->d_un.d_val; 812 break; 813 814 case DT_VERDEF: 815 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 816 dynp->d_un.d_val); 817 break; 818 819 case DT_VERDEFNUM: 820 obj->verdefnum = dynp->d_un.d_val; 821 break; 822 823 case DT_VERSYM: 824 obj->versyms = (const Elf_Versym *)(obj->relocbase + 825 dynp->d_un.d_val); 826 break; 827 828 case DT_HASH: 829 { 830 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 831 (obj->relocbase + dynp->d_un.d_ptr); 832 obj->nbuckets = hashtab[0]; 833 obj->nchains = hashtab[1]; 834 obj->buckets = hashtab + 2; 835 obj->chains = obj->buckets + obj->nbuckets; 836 } 837 break; 838 839 case DT_NEEDED: 840 if (!obj->rtld) { 841 Needed_Entry *nep = NEW(Needed_Entry); 842 nep->name = dynp->d_un.d_val; 843 nep->obj = NULL; 844 nep->next = NULL; 845 846 *needed_tail = nep; 847 needed_tail = &nep->next; 848 } 849 break; 850 851 case DT_FILTER: 852 if (!obj->rtld) { 853 Needed_Entry *nep = NEW(Needed_Entry); 854 nep->name = dynp->d_un.d_val; 855 nep->obj = NULL; 856 nep->next = NULL; 857 858 *needed_filtees_tail = nep; 859 needed_filtees_tail = &nep->next; 860 } 861 break; 862 863 case DT_AUXILIARY: 864 if (!obj->rtld) { 865 Needed_Entry *nep = NEW(Needed_Entry); 866 nep->name = dynp->d_un.d_val; 867 nep->obj = NULL; 868 nep->next = NULL; 869 870 *needed_aux_filtees_tail = nep; 871 needed_aux_filtees_tail = &nep->next; 872 } 873 break; 874 875 case DT_PLTGOT: 876 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 877 break; 878 879 case DT_TEXTREL: 880 obj->textrel = true; 881 break; 882 883 case DT_SYMBOLIC: 884 obj->symbolic = true; 885 break; 886 887 case DT_RPATH: 888 case DT_RUNPATH: /* XXX: process separately */ 889 /* 890 * We have to wait until later to process this, because we 891 * might not have gotten the address of the string table yet. 892 */ 893 *dyn_rpath = dynp; 894 break; 895 896 case DT_SONAME: 897 *dyn_soname = dynp; 898 break; 899 900 case DT_INIT: 901 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 902 break; 903 904 case DT_FINI: 905 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 906 break; 907 908 /* 909 * Don't process DT_DEBUG on MIPS as the dynamic section 910 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 911 */ 912 913 #ifndef __mips__ 914 case DT_DEBUG: 915 /* XXX - not implemented yet */ 916 if (!early) 917 dbg("Filling in DT_DEBUG entry"); 918 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 919 break; 920 #endif 921 922 case DT_FLAGS: 923 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 924 obj->z_origin = true; 925 if (dynp->d_un.d_val & DF_SYMBOLIC) 926 obj->symbolic = true; 927 if (dynp->d_un.d_val & DF_TEXTREL) 928 obj->textrel = true; 929 if (dynp->d_un.d_val & DF_BIND_NOW) 930 obj->bind_now = true; 931 if (dynp->d_un.d_val & DF_STATIC_TLS) 932 ; 933 break; 934 #ifdef __mips__ 935 case DT_MIPS_LOCAL_GOTNO: 936 obj->local_gotno = dynp->d_un.d_val; 937 break; 938 939 case DT_MIPS_SYMTABNO: 940 obj->symtabno = dynp->d_un.d_val; 941 break; 942 943 case DT_MIPS_GOTSYM: 944 obj->gotsym = dynp->d_un.d_val; 945 break; 946 947 case DT_MIPS_RLD_MAP: 948 #ifdef notyet 949 if (!early) 950 dbg("Filling in DT_DEBUG entry"); 951 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 952 #endif 953 break; 954 #endif 955 956 case DT_FLAGS_1: 957 if (dynp->d_un.d_val & DF_1_NOOPEN) 958 obj->z_noopen = true; 959 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 960 obj->z_origin = true; 961 if (dynp->d_un.d_val & DF_1_GLOBAL) 962 /* XXX */; 963 if (dynp->d_un.d_val & DF_1_BIND_NOW) 964 obj->bind_now = true; 965 if (dynp->d_un.d_val & DF_1_NODELETE) 966 obj->z_nodelete = true; 967 if (dynp->d_un.d_val & DF_1_LOADFLTR) 968 obj->z_loadfltr = true; 969 break; 970 971 default: 972 if (!early) { 973 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 974 (long)dynp->d_tag); 975 } 976 break; 977 } 978 } 979 980 obj->traced = false; 981 982 if (plttype == DT_RELA) { 983 obj->pltrela = (const Elf_Rela *) obj->pltrel; 984 obj->pltrel = NULL; 985 obj->pltrelasize = obj->pltrelsize; 986 obj->pltrelsize = 0; 987 } 988 } 989 990 static void 991 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 992 const Elf_Dyn *dyn_soname) 993 { 994 995 if (obj->z_origin && obj->origin_path == NULL) { 996 obj->origin_path = xmalloc(PATH_MAX); 997 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 998 die(); 999 } 1000 1001 if (dyn_rpath != NULL) { 1002 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1003 if (obj->z_origin) 1004 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1005 } 1006 1007 if (dyn_soname != NULL) 1008 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1009 } 1010 1011 static void 1012 digest_dynamic(Obj_Entry *obj, int early) 1013 { 1014 const Elf_Dyn *dyn_rpath; 1015 const Elf_Dyn *dyn_soname; 1016 1017 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1018 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1019 } 1020 1021 /* 1022 * Process a shared object's program header. This is used only for the 1023 * main program, when the kernel has already loaded the main program 1024 * into memory before calling the dynamic linker. It creates and 1025 * returns an Obj_Entry structure. 1026 */ 1027 static Obj_Entry * 1028 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1029 { 1030 Obj_Entry *obj; 1031 const Elf_Phdr *phlimit = phdr + phnum; 1032 const Elf_Phdr *ph; 1033 int nsegs = 0; 1034 1035 obj = obj_new(); 1036 for (ph = phdr; ph < phlimit; ph++) { 1037 if (ph->p_type != PT_PHDR) 1038 continue; 1039 1040 obj->phdr = phdr; 1041 obj->phsize = ph->p_memsz; 1042 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1043 break; 1044 } 1045 1046 obj->stack_flags = PF_X | PF_R | PF_W; 1047 1048 for (ph = phdr; ph < phlimit; ph++) { 1049 switch (ph->p_type) { 1050 1051 case PT_INTERP: 1052 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1053 break; 1054 1055 case PT_LOAD: 1056 if (nsegs == 0) { /* First load segment */ 1057 obj->vaddrbase = trunc_page(ph->p_vaddr); 1058 obj->mapbase = obj->vaddrbase + obj->relocbase; 1059 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1060 obj->vaddrbase; 1061 } else { /* Last load segment */ 1062 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1063 obj->vaddrbase; 1064 } 1065 nsegs++; 1066 break; 1067 1068 case PT_DYNAMIC: 1069 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1070 break; 1071 1072 case PT_TLS: 1073 obj->tlsindex = 1; 1074 obj->tlssize = ph->p_memsz; 1075 obj->tlsalign = ph->p_align; 1076 obj->tlsinitsize = ph->p_filesz; 1077 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1078 break; 1079 1080 case PT_GNU_STACK: 1081 obj->stack_flags = ph->p_flags; 1082 break; 1083 } 1084 } 1085 if (nsegs < 1) { 1086 _rtld_error("%s: too few PT_LOAD segments", path); 1087 return NULL; 1088 } 1089 1090 obj->entry = entry; 1091 return obj; 1092 } 1093 1094 static Obj_Entry * 1095 dlcheck(void *handle) 1096 { 1097 Obj_Entry *obj; 1098 1099 for (obj = obj_list; obj != NULL; obj = obj->next) 1100 if (obj == (Obj_Entry *) handle) 1101 break; 1102 1103 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1104 _rtld_error("Invalid shared object handle %p", handle); 1105 return NULL; 1106 } 1107 return obj; 1108 } 1109 1110 /* 1111 * If the given object is already in the donelist, return true. Otherwise 1112 * add the object to the list and return false. 1113 */ 1114 static bool 1115 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1116 { 1117 unsigned int i; 1118 1119 for (i = 0; i < dlp->num_used; i++) 1120 if (dlp->objs[i] == obj) 1121 return true; 1122 /* 1123 * Our donelist allocation should always be sufficient. But if 1124 * our threads locking isn't working properly, more shared objects 1125 * could have been loaded since we allocated the list. That should 1126 * never happen, but we'll handle it properly just in case it does. 1127 */ 1128 if (dlp->num_used < dlp->num_alloc) 1129 dlp->objs[dlp->num_used++] = obj; 1130 return false; 1131 } 1132 1133 /* 1134 * Hash function for symbol table lookup. Don't even think about changing 1135 * this. It is specified by the System V ABI. 1136 */ 1137 unsigned long 1138 elf_hash(const char *name) 1139 { 1140 const unsigned char *p = (const unsigned char *) name; 1141 unsigned long h = 0; 1142 unsigned long g; 1143 1144 while (*p != '\0') { 1145 h = (h << 4) + *p++; 1146 if ((g = h & 0xf0000000) != 0) 1147 h ^= g >> 24; 1148 h &= ~g; 1149 } 1150 return h; 1151 } 1152 1153 /* 1154 * Find the library with the given name, and return its full pathname. 1155 * The returned string is dynamically allocated. Generates an error 1156 * message and returns NULL if the library cannot be found. 1157 * 1158 * If the second argument is non-NULL, then it refers to an already- 1159 * loaded shared object, whose library search path will be searched. 1160 * 1161 * The search order is: 1162 * LD_LIBRARY_PATH 1163 * rpath in the referencing file 1164 * ldconfig hints 1165 * /lib:/usr/lib 1166 */ 1167 static char * 1168 find_library(const char *xname, const Obj_Entry *refobj) 1169 { 1170 char *pathname; 1171 char *name; 1172 1173 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1174 if (xname[0] != '/' && !trust) { 1175 _rtld_error("Absolute pathname required for shared object \"%s\"", 1176 xname); 1177 return NULL; 1178 } 1179 if (refobj != NULL && refobj->z_origin) 1180 return origin_subst(xname, refobj->origin_path); 1181 else 1182 return xstrdup(xname); 1183 } 1184 1185 if (libmap_disable || (refobj == NULL) || 1186 (name = lm_find(refobj->path, xname)) == NULL) 1187 name = (char *)xname; 1188 1189 dbg(" Searching for \"%s\"", name); 1190 1191 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1192 (refobj != NULL && 1193 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1194 (pathname = search_library_path(name, gethints())) != NULL || 1195 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1196 return pathname; 1197 1198 if(refobj != NULL && refobj->path != NULL) { 1199 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1200 name, basename(refobj->path)); 1201 } else { 1202 _rtld_error("Shared object \"%s\" not found", name); 1203 } 1204 return NULL; 1205 } 1206 1207 /* 1208 * Given a symbol number in a referencing object, find the corresponding 1209 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1210 * no definition was found. Returns a pointer to the Obj_Entry of the 1211 * defining object via the reference parameter DEFOBJ_OUT. 1212 */ 1213 const Elf_Sym * 1214 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1215 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1216 RtldLockState *lockstate) 1217 { 1218 const Elf_Sym *ref; 1219 const Elf_Sym *def; 1220 const Obj_Entry *defobj; 1221 SymLook req; 1222 const char *name; 1223 int res; 1224 1225 /* 1226 * If we have already found this symbol, get the information from 1227 * the cache. 1228 */ 1229 if (symnum >= refobj->nchains) 1230 return NULL; /* Bad object */ 1231 if (cache != NULL && cache[symnum].sym != NULL) { 1232 *defobj_out = cache[symnum].obj; 1233 return cache[symnum].sym; 1234 } 1235 1236 ref = refobj->symtab + symnum; 1237 name = refobj->strtab + ref->st_name; 1238 def = NULL; 1239 defobj = NULL; 1240 1241 /* 1242 * We don't have to do a full scale lookup if the symbol is local. 1243 * We know it will bind to the instance in this load module; to 1244 * which we already have a pointer (ie ref). By not doing a lookup, 1245 * we not only improve performance, but it also avoids unresolvable 1246 * symbols when local symbols are not in the hash table. This has 1247 * been seen with the ia64 toolchain. 1248 */ 1249 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1250 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1251 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1252 symnum); 1253 } 1254 symlook_init(&req, name); 1255 req.flags = flags; 1256 req.ventry = fetch_ventry(refobj, symnum); 1257 req.lockstate = lockstate; 1258 res = symlook_default(&req, refobj); 1259 if (res == 0) { 1260 def = req.sym_out; 1261 defobj = req.defobj_out; 1262 } 1263 } else { 1264 def = ref; 1265 defobj = refobj; 1266 } 1267 1268 /* 1269 * If we found no definition and the reference is weak, treat the 1270 * symbol as having the value zero. 1271 */ 1272 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1273 def = &sym_zero; 1274 defobj = obj_main; 1275 } 1276 1277 if (def != NULL) { 1278 *defobj_out = defobj; 1279 /* Record the information in the cache to avoid subsequent lookups. */ 1280 if (cache != NULL) { 1281 cache[symnum].sym = def; 1282 cache[symnum].obj = defobj; 1283 } 1284 } else { 1285 if (refobj != &obj_rtld) 1286 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1287 } 1288 return def; 1289 } 1290 1291 /* 1292 * Return the search path from the ldconfig hints file, reading it if 1293 * necessary. Returns NULL if there are problems with the hints file, 1294 * or if the search path there is empty. 1295 */ 1296 static const char * 1297 gethints(void) 1298 { 1299 static char *hints; 1300 1301 if (hints == NULL) { 1302 int fd; 1303 struct elfhints_hdr hdr; 1304 char *p; 1305 1306 /* Keep from trying again in case the hints file is bad. */ 1307 hints = ""; 1308 1309 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1310 return NULL; 1311 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1312 hdr.magic != ELFHINTS_MAGIC || 1313 hdr.version != 1) { 1314 close(fd); 1315 return NULL; 1316 } 1317 p = xmalloc(hdr.dirlistlen + 1); 1318 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1319 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1320 free(p); 1321 close(fd); 1322 return NULL; 1323 } 1324 hints = p; 1325 close(fd); 1326 } 1327 return hints[0] != '\0' ? hints : NULL; 1328 } 1329 1330 static void 1331 init_dag(Obj_Entry *root) 1332 { 1333 const Needed_Entry *needed; 1334 const Objlist_Entry *elm; 1335 DoneList donelist; 1336 1337 if (root->dag_inited) 1338 return; 1339 donelist_init(&donelist); 1340 1341 /* Root object belongs to own DAG. */ 1342 objlist_push_tail(&root->dldags, root); 1343 objlist_push_tail(&root->dagmembers, root); 1344 donelist_check(&donelist, root); 1345 1346 /* 1347 * Add dependencies of root object to DAG in breadth order 1348 * by exploiting the fact that each new object get added 1349 * to the tail of the dagmembers list. 1350 */ 1351 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1352 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1353 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1354 continue; 1355 objlist_push_tail(&needed->obj->dldags, root); 1356 objlist_push_tail(&root->dagmembers, needed->obj); 1357 } 1358 } 1359 root->dag_inited = true; 1360 } 1361 1362 /* 1363 * Initialize the dynamic linker. The argument is the address at which 1364 * the dynamic linker has been mapped into memory. The primary task of 1365 * this function is to relocate the dynamic linker. 1366 */ 1367 static void 1368 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1369 { 1370 Obj_Entry objtmp; /* Temporary rtld object */ 1371 const Elf_Dyn *dyn_rpath; 1372 const Elf_Dyn *dyn_soname; 1373 1374 /* 1375 * Conjure up an Obj_Entry structure for the dynamic linker. 1376 * 1377 * The "path" member can't be initialized yet because string constants 1378 * cannot yet be accessed. Below we will set it correctly. 1379 */ 1380 memset(&objtmp, 0, sizeof(objtmp)); 1381 objtmp.path = NULL; 1382 objtmp.rtld = true; 1383 objtmp.mapbase = mapbase; 1384 #ifdef PIC 1385 objtmp.relocbase = mapbase; 1386 #endif 1387 if (RTLD_IS_DYNAMIC()) { 1388 objtmp.dynamic = rtld_dynamic(&objtmp); 1389 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1390 assert(objtmp.needed == NULL); 1391 #if !defined(__mips__) 1392 /* MIPS has a bogus DT_TEXTREL. */ 1393 assert(!objtmp.textrel); 1394 #endif 1395 1396 /* 1397 * Temporarily put the dynamic linker entry into the object list, so 1398 * that symbols can be found. 1399 */ 1400 1401 relocate_objects(&objtmp, true, &objtmp, NULL); 1402 } 1403 1404 /* Initialize the object list. */ 1405 obj_tail = &obj_list; 1406 1407 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1408 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1409 1410 if (aux_info[AT_PAGESZ] != NULL) 1411 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1412 if (aux_info[AT_OSRELDATE] != NULL) 1413 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1414 1415 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1416 1417 /* Replace the path with a dynamically allocated copy. */ 1418 obj_rtld.path = xstrdup(PATH_RTLD); 1419 1420 r_debug.r_brk = r_debug_state; 1421 r_debug.r_state = RT_CONSISTENT; 1422 } 1423 1424 /* 1425 * Add the init functions from a needed object list (and its recursive 1426 * needed objects) to "list". This is not used directly; it is a helper 1427 * function for initlist_add_objects(). The write lock must be held 1428 * when this function is called. 1429 */ 1430 static void 1431 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1432 { 1433 /* Recursively process the successor needed objects. */ 1434 if (needed->next != NULL) 1435 initlist_add_neededs(needed->next, list); 1436 1437 /* Process the current needed object. */ 1438 if (needed->obj != NULL) 1439 initlist_add_objects(needed->obj, &needed->obj->next, list); 1440 } 1441 1442 /* 1443 * Scan all of the DAGs rooted in the range of objects from "obj" to 1444 * "tail" and add their init functions to "list". This recurses over 1445 * the DAGs and ensure the proper init ordering such that each object's 1446 * needed libraries are initialized before the object itself. At the 1447 * same time, this function adds the objects to the global finalization 1448 * list "list_fini" in the opposite order. The write lock must be 1449 * held when this function is called. 1450 */ 1451 static void 1452 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1453 { 1454 if (obj->init_scanned || obj->init_done) 1455 return; 1456 obj->init_scanned = true; 1457 1458 /* Recursively process the successor objects. */ 1459 if (&obj->next != tail) 1460 initlist_add_objects(obj->next, tail, list); 1461 1462 /* Recursively process the needed objects. */ 1463 if (obj->needed != NULL) 1464 initlist_add_neededs(obj->needed, list); 1465 1466 /* Add the object to the init list. */ 1467 if (obj->init != (Elf_Addr)NULL) 1468 objlist_push_tail(list, obj); 1469 1470 /* Add the object to the global fini list in the reverse order. */ 1471 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1472 objlist_push_head(&list_fini, obj); 1473 obj->on_fini_list = true; 1474 } 1475 } 1476 1477 #ifndef FPTR_TARGET 1478 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1479 #endif 1480 1481 static void 1482 free_needed_filtees(Needed_Entry *n) 1483 { 1484 Needed_Entry *needed, *needed1; 1485 1486 for (needed = n; needed != NULL; needed = needed->next) { 1487 if (needed->obj != NULL) { 1488 dlclose(needed->obj); 1489 needed->obj = NULL; 1490 } 1491 } 1492 for (needed = n; needed != NULL; needed = needed1) { 1493 needed1 = needed->next; 1494 free(needed); 1495 } 1496 } 1497 1498 static void 1499 unload_filtees(Obj_Entry *obj) 1500 { 1501 1502 free_needed_filtees(obj->needed_filtees); 1503 obj->needed_filtees = NULL; 1504 free_needed_filtees(obj->needed_aux_filtees); 1505 obj->needed_aux_filtees = NULL; 1506 obj->filtees_loaded = false; 1507 } 1508 1509 static void 1510 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags) 1511 { 1512 1513 for (; needed != NULL; needed = needed->next) { 1514 needed->obj = dlopen_object(obj->strtab + needed->name, obj, 1515 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1516 RTLD_LOCAL); 1517 } 1518 } 1519 1520 static void 1521 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1522 { 1523 1524 lock_restart_for_upgrade(lockstate); 1525 if (!obj->filtees_loaded) { 1526 load_filtee1(obj, obj->needed_filtees, flags); 1527 load_filtee1(obj, obj->needed_aux_filtees, flags); 1528 obj->filtees_loaded = true; 1529 } 1530 } 1531 1532 static int 1533 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1534 { 1535 Obj_Entry *obj1; 1536 1537 for (; needed != NULL; needed = needed->next) { 1538 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1539 flags & ~RTLD_LO_NOLOAD); 1540 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1541 return (-1); 1542 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1543 dbg("obj %s nodelete", obj1->path); 1544 init_dag(obj1); 1545 ref_dag(obj1); 1546 obj1->ref_nodel = true; 1547 } 1548 } 1549 return (0); 1550 } 1551 1552 /* 1553 * Given a shared object, traverse its list of needed objects, and load 1554 * each of them. Returns 0 on success. Generates an error message and 1555 * returns -1 on failure. 1556 */ 1557 static int 1558 load_needed_objects(Obj_Entry *first, int flags) 1559 { 1560 Obj_Entry *obj; 1561 1562 for (obj = first; obj != NULL; obj = obj->next) { 1563 if (process_needed(obj, obj->needed, flags) == -1) 1564 return (-1); 1565 } 1566 return (0); 1567 } 1568 1569 static int 1570 load_preload_objects(void) 1571 { 1572 char *p = ld_preload; 1573 static const char delim[] = " \t:;"; 1574 1575 if (p == NULL) 1576 return 0; 1577 1578 p += strspn(p, delim); 1579 while (*p != '\0') { 1580 size_t len = strcspn(p, delim); 1581 char savech; 1582 1583 savech = p[len]; 1584 p[len] = '\0'; 1585 if (load_object(p, NULL, 0) == NULL) 1586 return -1; /* XXX - cleanup */ 1587 p[len] = savech; 1588 p += len; 1589 p += strspn(p, delim); 1590 } 1591 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1592 return 0; 1593 } 1594 1595 /* 1596 * Load a shared object into memory, if it is not already loaded. 1597 * 1598 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1599 * on failure. 1600 */ 1601 static Obj_Entry * 1602 load_object(const char *name, const Obj_Entry *refobj, int flags) 1603 { 1604 Obj_Entry *obj; 1605 int fd = -1; 1606 struct stat sb; 1607 char *path; 1608 1609 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1610 if (object_match_name(obj, name)) 1611 return obj; 1612 1613 path = find_library(name, refobj); 1614 if (path == NULL) 1615 return NULL; 1616 1617 /* 1618 * If we didn't find a match by pathname, open the file and check 1619 * again by device and inode. This avoids false mismatches caused 1620 * by multiple links or ".." in pathnames. 1621 * 1622 * To avoid a race, we open the file and use fstat() rather than 1623 * using stat(). 1624 */ 1625 if ((fd = open(path, O_RDONLY)) == -1) { 1626 _rtld_error("Cannot open \"%s\"", path); 1627 free(path); 1628 return NULL; 1629 } 1630 if (fstat(fd, &sb) == -1) { 1631 _rtld_error("Cannot fstat \"%s\"", path); 1632 close(fd); 1633 free(path); 1634 return NULL; 1635 } 1636 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1637 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1638 close(fd); 1639 break; 1640 } 1641 } 1642 if (obj != NULL) { 1643 object_add_name(obj, name); 1644 free(path); 1645 close(fd); 1646 return obj; 1647 } 1648 if (flags & RTLD_LO_NOLOAD) { 1649 free(path); 1650 return (NULL); 1651 } 1652 1653 /* First use of this object, so we must map it in */ 1654 obj = do_load_object(fd, name, path, &sb, flags); 1655 if (obj == NULL) 1656 free(path); 1657 close(fd); 1658 1659 return obj; 1660 } 1661 1662 static Obj_Entry * 1663 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1664 int flags) 1665 { 1666 Obj_Entry *obj; 1667 struct statfs fs; 1668 1669 /* 1670 * but first, make sure that environment variables haven't been 1671 * used to circumvent the noexec flag on a filesystem. 1672 */ 1673 if (dangerous_ld_env) { 1674 if (fstatfs(fd, &fs) != 0) { 1675 _rtld_error("Cannot fstatfs \"%s\"", path); 1676 return NULL; 1677 } 1678 if (fs.f_flags & MNT_NOEXEC) { 1679 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1680 return NULL; 1681 } 1682 } 1683 dbg("loading \"%s\"", path); 1684 obj = map_object(fd, path, sbp); 1685 if (obj == NULL) 1686 return NULL; 1687 1688 object_add_name(obj, name); 1689 obj->path = path; 1690 digest_dynamic(obj, 0); 1691 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1692 RTLD_LO_DLOPEN) { 1693 dbg("refusing to load non-loadable \"%s\"", obj->path); 1694 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1695 munmap(obj->mapbase, obj->mapsize); 1696 obj_free(obj); 1697 return (NULL); 1698 } 1699 1700 *obj_tail = obj; 1701 obj_tail = &obj->next; 1702 obj_count++; 1703 obj_loads++; 1704 linkmap_add(obj); /* for GDB & dlinfo() */ 1705 max_stack_flags |= obj->stack_flags; 1706 1707 dbg(" %p .. %p: %s", obj->mapbase, 1708 obj->mapbase + obj->mapsize - 1, obj->path); 1709 if (obj->textrel) 1710 dbg(" WARNING: %s has impure text", obj->path); 1711 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1712 obj->path); 1713 1714 return obj; 1715 } 1716 1717 static Obj_Entry * 1718 obj_from_addr(const void *addr) 1719 { 1720 Obj_Entry *obj; 1721 1722 for (obj = obj_list; obj != NULL; obj = obj->next) { 1723 if (addr < (void *) obj->mapbase) 1724 continue; 1725 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1726 return obj; 1727 } 1728 return NULL; 1729 } 1730 1731 /* 1732 * Call the finalization functions for each of the objects in "list" 1733 * belonging to the DAG of "root" and referenced once. If NULL "root" 1734 * is specified, every finalization function will be called regardless 1735 * of the reference count and the list elements won't be freed. All of 1736 * the objects are expected to have non-NULL fini functions. 1737 */ 1738 static void 1739 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1740 { 1741 Objlist_Entry *elm; 1742 char *saved_msg; 1743 1744 assert(root == NULL || root->refcount == 1); 1745 1746 /* 1747 * Preserve the current error message since a fini function might 1748 * call into the dynamic linker and overwrite it. 1749 */ 1750 saved_msg = errmsg_save(); 1751 do { 1752 STAILQ_FOREACH(elm, list, link) { 1753 if (root != NULL && (elm->obj->refcount != 1 || 1754 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1755 continue; 1756 dbg("calling fini function for %s at %p", elm->obj->path, 1757 (void *)elm->obj->fini); 1758 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1759 elm->obj->path); 1760 /* Remove object from fini list to prevent recursive invocation. */ 1761 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1762 /* 1763 * XXX: If a dlopen() call references an object while the 1764 * fini function is in progress, we might end up trying to 1765 * unload the referenced object in dlclose() or the object 1766 * won't be unloaded although its fini function has been 1767 * called. 1768 */ 1769 lock_release(rtld_bind_lock, lockstate); 1770 call_initfini_pointer(elm->obj, elm->obj->fini); 1771 wlock_acquire(rtld_bind_lock, lockstate); 1772 /* No need to free anything if process is going down. */ 1773 if (root != NULL) 1774 free(elm); 1775 /* 1776 * We must restart the list traversal after every fini call 1777 * because a dlclose() call from the fini function or from 1778 * another thread might have modified the reference counts. 1779 */ 1780 break; 1781 } 1782 } while (elm != NULL); 1783 errmsg_restore(saved_msg); 1784 } 1785 1786 /* 1787 * Call the initialization functions for each of the objects in 1788 * "list". All of the objects are expected to have non-NULL init 1789 * functions. 1790 */ 1791 static void 1792 objlist_call_init(Objlist *list, RtldLockState *lockstate) 1793 { 1794 Objlist_Entry *elm; 1795 Obj_Entry *obj; 1796 char *saved_msg; 1797 1798 /* 1799 * Clean init_scanned flag so that objects can be rechecked and 1800 * possibly initialized earlier if any of vectors called below 1801 * cause the change by using dlopen. 1802 */ 1803 for (obj = obj_list; obj != NULL; obj = obj->next) 1804 obj->init_scanned = false; 1805 1806 /* 1807 * Preserve the current error message since an init function might 1808 * call into the dynamic linker and overwrite it. 1809 */ 1810 saved_msg = errmsg_save(); 1811 STAILQ_FOREACH(elm, list, link) { 1812 if (elm->obj->init_done) /* Initialized early. */ 1813 continue; 1814 dbg("calling init function for %s at %p", elm->obj->path, 1815 (void *)elm->obj->init); 1816 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1817 elm->obj->path); 1818 /* 1819 * Race: other thread might try to use this object before current 1820 * one completes the initilization. Not much can be done here 1821 * without better locking. 1822 */ 1823 elm->obj->init_done = true; 1824 lock_release(rtld_bind_lock, lockstate); 1825 call_initfini_pointer(elm->obj, elm->obj->init); 1826 wlock_acquire(rtld_bind_lock, lockstate); 1827 } 1828 errmsg_restore(saved_msg); 1829 } 1830 1831 static void 1832 objlist_clear(Objlist *list) 1833 { 1834 Objlist_Entry *elm; 1835 1836 while (!STAILQ_EMPTY(list)) { 1837 elm = STAILQ_FIRST(list); 1838 STAILQ_REMOVE_HEAD(list, link); 1839 free(elm); 1840 } 1841 } 1842 1843 static Objlist_Entry * 1844 objlist_find(Objlist *list, const Obj_Entry *obj) 1845 { 1846 Objlist_Entry *elm; 1847 1848 STAILQ_FOREACH(elm, list, link) 1849 if (elm->obj == obj) 1850 return elm; 1851 return NULL; 1852 } 1853 1854 static void 1855 objlist_init(Objlist *list) 1856 { 1857 STAILQ_INIT(list); 1858 } 1859 1860 static void 1861 objlist_push_head(Objlist *list, Obj_Entry *obj) 1862 { 1863 Objlist_Entry *elm; 1864 1865 elm = NEW(Objlist_Entry); 1866 elm->obj = obj; 1867 STAILQ_INSERT_HEAD(list, elm, link); 1868 } 1869 1870 static void 1871 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1872 { 1873 Objlist_Entry *elm; 1874 1875 elm = NEW(Objlist_Entry); 1876 elm->obj = obj; 1877 STAILQ_INSERT_TAIL(list, elm, link); 1878 } 1879 1880 static void 1881 objlist_remove(Objlist *list, Obj_Entry *obj) 1882 { 1883 Objlist_Entry *elm; 1884 1885 if ((elm = objlist_find(list, obj)) != NULL) { 1886 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1887 free(elm); 1888 } 1889 } 1890 1891 /* 1892 * Relocate newly-loaded shared objects. The argument is a pointer to 1893 * the Obj_Entry for the first such object. All objects from the first 1894 * to the end of the list of objects are relocated. Returns 0 on success, 1895 * or -1 on failure. 1896 */ 1897 static int 1898 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 1899 RtldLockState *lockstate) 1900 { 1901 Obj_Entry *obj; 1902 1903 for (obj = first; obj != NULL; obj = obj->next) { 1904 if (obj != rtldobj) 1905 dbg("relocating \"%s\"", obj->path); 1906 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1907 obj->symtab == NULL || obj->strtab == NULL) { 1908 _rtld_error("%s: Shared object has no run-time symbol table", 1909 obj->path); 1910 return -1; 1911 } 1912 1913 if (obj->textrel) { 1914 /* There are relocations to the write-protected text segment. */ 1915 if (mprotect(obj->mapbase, obj->textsize, 1916 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1917 _rtld_error("%s: Cannot write-enable text segment: %s", 1918 obj->path, strerror(errno)); 1919 return -1; 1920 } 1921 } 1922 1923 /* Process the non-PLT relocations. */ 1924 if (reloc_non_plt(obj, rtldobj, lockstate)) 1925 return -1; 1926 1927 if (obj->textrel) { /* Re-protected the text segment. */ 1928 if (mprotect(obj->mapbase, obj->textsize, 1929 PROT_READ|PROT_EXEC) == -1) { 1930 _rtld_error("%s: Cannot write-protect text segment: %s", 1931 obj->path, strerror(errno)); 1932 return -1; 1933 } 1934 } 1935 1936 /* Process the PLT relocations. */ 1937 if (reloc_plt(obj) == -1) 1938 return -1; 1939 /* Relocate the jump slots if we are doing immediate binding. */ 1940 if (obj->bind_now || bind_now) 1941 if (reloc_jmpslots(obj, lockstate) == -1) 1942 return -1; 1943 1944 1945 /* 1946 * Set up the magic number and version in the Obj_Entry. These 1947 * were checked in the crt1.o from the original ElfKit, so we 1948 * set them for backward compatibility. 1949 */ 1950 obj->magic = RTLD_MAGIC; 1951 obj->version = RTLD_VERSION; 1952 1953 /* Set the special PLT or GOT entries. */ 1954 init_pltgot(obj); 1955 } 1956 1957 return 0; 1958 } 1959 1960 /* 1961 * Cleanup procedure. It will be called (by the atexit mechanism) just 1962 * before the process exits. 1963 */ 1964 static void 1965 rtld_exit(void) 1966 { 1967 RtldLockState lockstate; 1968 1969 wlock_acquire(rtld_bind_lock, &lockstate); 1970 dbg("rtld_exit()"); 1971 objlist_call_fini(&list_fini, NULL, &lockstate); 1972 /* No need to remove the items from the list, since we are exiting. */ 1973 if (!libmap_disable) 1974 lm_fini(); 1975 lock_release(rtld_bind_lock, &lockstate); 1976 } 1977 1978 static void * 1979 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1980 { 1981 #ifdef COMPAT_32BIT 1982 const char *trans; 1983 #endif 1984 if (path == NULL) 1985 return (NULL); 1986 1987 path += strspn(path, ":;"); 1988 while (*path != '\0') { 1989 size_t len; 1990 char *res; 1991 1992 len = strcspn(path, ":;"); 1993 #ifdef COMPAT_32BIT 1994 trans = lm_findn(NULL, path, len); 1995 if (trans) 1996 res = callback(trans, strlen(trans), arg); 1997 else 1998 #endif 1999 res = callback(path, len, arg); 2000 2001 if (res != NULL) 2002 return (res); 2003 2004 path += len; 2005 path += strspn(path, ":;"); 2006 } 2007 2008 return (NULL); 2009 } 2010 2011 struct try_library_args { 2012 const char *name; 2013 size_t namelen; 2014 char *buffer; 2015 size_t buflen; 2016 }; 2017 2018 static void * 2019 try_library_path(const char *dir, size_t dirlen, void *param) 2020 { 2021 struct try_library_args *arg; 2022 2023 arg = param; 2024 if (*dir == '/' || trust) { 2025 char *pathname; 2026 2027 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2028 return (NULL); 2029 2030 pathname = arg->buffer; 2031 strncpy(pathname, dir, dirlen); 2032 pathname[dirlen] = '/'; 2033 strcpy(pathname + dirlen + 1, arg->name); 2034 2035 dbg(" Trying \"%s\"", pathname); 2036 if (access(pathname, F_OK) == 0) { /* We found it */ 2037 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2038 strcpy(pathname, arg->buffer); 2039 return (pathname); 2040 } 2041 } 2042 return (NULL); 2043 } 2044 2045 static char * 2046 search_library_path(const char *name, const char *path) 2047 { 2048 char *p; 2049 struct try_library_args arg; 2050 2051 if (path == NULL) 2052 return NULL; 2053 2054 arg.name = name; 2055 arg.namelen = strlen(name); 2056 arg.buffer = xmalloc(PATH_MAX); 2057 arg.buflen = PATH_MAX; 2058 2059 p = path_enumerate(path, try_library_path, &arg); 2060 2061 free(arg.buffer); 2062 2063 return (p); 2064 } 2065 2066 int 2067 dlclose(void *handle) 2068 { 2069 Obj_Entry *root; 2070 RtldLockState lockstate; 2071 2072 wlock_acquire(rtld_bind_lock, &lockstate); 2073 root = dlcheck(handle); 2074 if (root == NULL) { 2075 lock_release(rtld_bind_lock, &lockstate); 2076 return -1; 2077 } 2078 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2079 root->path); 2080 2081 /* Unreference the object and its dependencies. */ 2082 root->dl_refcount--; 2083 2084 if (root->refcount == 1) { 2085 /* 2086 * The object will be no longer referenced, so we must unload it. 2087 * First, call the fini functions. 2088 */ 2089 objlist_call_fini(&list_fini, root, &lockstate); 2090 2091 unref_dag(root); 2092 2093 /* Finish cleaning up the newly-unreferenced objects. */ 2094 GDB_STATE(RT_DELETE,&root->linkmap); 2095 unload_object(root); 2096 GDB_STATE(RT_CONSISTENT,NULL); 2097 } else 2098 unref_dag(root); 2099 2100 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2101 lock_release(rtld_bind_lock, &lockstate); 2102 return 0; 2103 } 2104 2105 char * 2106 dlerror(void) 2107 { 2108 char *msg = error_message; 2109 error_message = NULL; 2110 return msg; 2111 } 2112 2113 /* 2114 * This function is deprecated and has no effect. 2115 */ 2116 void 2117 dllockinit(void *context, 2118 void *(*lock_create)(void *context), 2119 void (*rlock_acquire)(void *lock), 2120 void (*wlock_acquire)(void *lock), 2121 void (*lock_release)(void *lock), 2122 void (*lock_destroy)(void *lock), 2123 void (*context_destroy)(void *context)) 2124 { 2125 static void *cur_context; 2126 static void (*cur_context_destroy)(void *); 2127 2128 /* Just destroy the context from the previous call, if necessary. */ 2129 if (cur_context_destroy != NULL) 2130 cur_context_destroy(cur_context); 2131 cur_context = context; 2132 cur_context_destroy = context_destroy; 2133 } 2134 2135 void * 2136 dlopen(const char *name, int mode) 2137 { 2138 RtldLockState lockstate; 2139 int lo_flags; 2140 2141 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2142 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2143 if (ld_tracing != NULL) { 2144 rlock_acquire(rtld_bind_lock, &lockstate); 2145 if (sigsetjmp(lockstate.env, 0) != 0) 2146 lock_upgrade(rtld_bind_lock, &lockstate); 2147 environ = (char **)*get_program_var_addr("environ", &lockstate); 2148 lock_release(rtld_bind_lock, &lockstate); 2149 } 2150 lo_flags = RTLD_LO_DLOPEN; 2151 if (mode & RTLD_NODELETE) 2152 lo_flags |= RTLD_LO_NODELETE; 2153 if (mode & RTLD_NOLOAD) 2154 lo_flags |= RTLD_LO_NOLOAD; 2155 if (ld_tracing != NULL) 2156 lo_flags |= RTLD_LO_TRACE; 2157 2158 return (dlopen_object(name, obj_main, lo_flags, 2159 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2160 } 2161 2162 static Obj_Entry * 2163 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode) 2164 { 2165 Obj_Entry **old_obj_tail; 2166 Obj_Entry *obj; 2167 Objlist initlist; 2168 RtldLockState lockstate; 2169 int result; 2170 2171 objlist_init(&initlist); 2172 2173 wlock_acquire(rtld_bind_lock, &lockstate); 2174 GDB_STATE(RT_ADD,NULL); 2175 2176 old_obj_tail = obj_tail; 2177 obj = NULL; 2178 if (name == NULL) { 2179 obj = obj_main; 2180 obj->refcount++; 2181 } else { 2182 obj = load_object(name, refobj, lo_flags); 2183 } 2184 2185 if (obj) { 2186 obj->dl_refcount++; 2187 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2188 objlist_push_tail(&list_global, obj); 2189 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2190 assert(*old_obj_tail == obj); 2191 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN); 2192 init_dag(obj); 2193 ref_dag(obj); 2194 if (result != -1) 2195 result = rtld_verify_versions(&obj->dagmembers); 2196 if (result != -1 && ld_tracing) 2197 goto trace; 2198 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK) 2199 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) { 2200 obj->dl_refcount--; 2201 unref_dag(obj); 2202 if (obj->refcount == 0) 2203 unload_object(obj); 2204 obj = NULL; 2205 } else { 2206 /* Make list of init functions to call. */ 2207 initlist_add_objects(obj, &obj->next, &initlist); 2208 } 2209 } else { 2210 2211 /* 2212 * Bump the reference counts for objects on this DAG. If 2213 * this is the first dlopen() call for the object that was 2214 * already loaded as a dependency, initialize the dag 2215 * starting at it. 2216 */ 2217 init_dag(obj); 2218 ref_dag(obj); 2219 2220 if ((lo_flags & RTLD_LO_TRACE) != 0) 2221 goto trace; 2222 } 2223 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2224 obj->z_nodelete) && !obj->ref_nodel) { 2225 dbg("obj %s nodelete", obj->path); 2226 ref_dag(obj); 2227 obj->z_nodelete = obj->ref_nodel = true; 2228 } 2229 } 2230 2231 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2232 name); 2233 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2234 2235 map_stacks_exec(&lockstate); 2236 2237 /* Call the init functions. */ 2238 objlist_call_init(&initlist, &lockstate); 2239 objlist_clear(&initlist); 2240 lock_release(rtld_bind_lock, &lockstate); 2241 return obj; 2242 trace: 2243 trace_loaded_objects(obj); 2244 lock_release(rtld_bind_lock, &lockstate); 2245 exit(0); 2246 } 2247 2248 static void * 2249 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2250 int flags) 2251 { 2252 DoneList donelist; 2253 const Obj_Entry *obj, *defobj; 2254 const Elf_Sym *def; 2255 SymLook req; 2256 RtldLockState lockstate; 2257 int res; 2258 2259 def = NULL; 2260 defobj = NULL; 2261 symlook_init(&req, name); 2262 req.ventry = ve; 2263 req.flags = flags | SYMLOOK_IN_PLT; 2264 req.lockstate = &lockstate; 2265 2266 rlock_acquire(rtld_bind_lock, &lockstate); 2267 if (sigsetjmp(lockstate.env, 0) != 0) 2268 lock_upgrade(rtld_bind_lock, &lockstate); 2269 if (handle == NULL || handle == RTLD_NEXT || 2270 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2271 2272 if ((obj = obj_from_addr(retaddr)) == NULL) { 2273 _rtld_error("Cannot determine caller's shared object"); 2274 lock_release(rtld_bind_lock, &lockstate); 2275 return NULL; 2276 } 2277 if (handle == NULL) { /* Just the caller's shared object. */ 2278 res = symlook_obj(&req, obj); 2279 if (res == 0) { 2280 def = req.sym_out; 2281 defobj = req.defobj_out; 2282 } 2283 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2284 handle == RTLD_SELF) { /* ... caller included */ 2285 if (handle == RTLD_NEXT) 2286 obj = obj->next; 2287 for (; obj != NULL; obj = obj->next) { 2288 res = symlook_obj(&req, obj); 2289 if (res == 0) { 2290 if (def == NULL || 2291 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2292 def = req.sym_out; 2293 defobj = req.defobj_out; 2294 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2295 break; 2296 } 2297 } 2298 } 2299 /* 2300 * Search the dynamic linker itself, and possibly resolve the 2301 * symbol from there. This is how the application links to 2302 * dynamic linker services such as dlopen. 2303 */ 2304 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2305 res = symlook_obj(&req, &obj_rtld); 2306 if (res == 0) { 2307 def = req.sym_out; 2308 defobj = req.defobj_out; 2309 } 2310 } 2311 } else { 2312 assert(handle == RTLD_DEFAULT); 2313 res = symlook_default(&req, obj); 2314 if (res == 0) { 2315 defobj = req.defobj_out; 2316 def = req.sym_out; 2317 } 2318 } 2319 } else { 2320 if ((obj = dlcheck(handle)) == NULL) { 2321 lock_release(rtld_bind_lock, &lockstate); 2322 return NULL; 2323 } 2324 2325 donelist_init(&donelist); 2326 if (obj->mainprog) { 2327 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2328 res = symlook_global(&req, &donelist); 2329 if (res == 0) { 2330 def = req.sym_out; 2331 defobj = req.defobj_out; 2332 } 2333 /* 2334 * Search the dynamic linker itself, and possibly resolve the 2335 * symbol from there. This is how the application links to 2336 * dynamic linker services such as dlopen. 2337 */ 2338 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2339 res = symlook_obj(&req, &obj_rtld); 2340 if (res == 0) { 2341 def = req.sym_out; 2342 defobj = req.defobj_out; 2343 } 2344 } 2345 } 2346 else { 2347 /* Search the whole DAG rooted at the given object. */ 2348 res = symlook_list(&req, &obj->dagmembers, &donelist); 2349 if (res == 0) { 2350 def = req.sym_out; 2351 defobj = req.defobj_out; 2352 } 2353 } 2354 } 2355 2356 if (def != NULL) { 2357 lock_release(rtld_bind_lock, &lockstate); 2358 2359 /* 2360 * The value required by the caller is derived from the value 2361 * of the symbol. For the ia64 architecture, we need to 2362 * construct a function descriptor which the caller can use to 2363 * call the function with the right 'gp' value. For other 2364 * architectures and for non-functions, the value is simply 2365 * the relocated value of the symbol. 2366 */ 2367 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2368 return make_function_pointer(def, defobj); 2369 else 2370 return defobj->relocbase + def->st_value; 2371 } 2372 2373 _rtld_error("Undefined symbol \"%s\"", name); 2374 lock_release(rtld_bind_lock, &lockstate); 2375 return NULL; 2376 } 2377 2378 void * 2379 dlsym(void *handle, const char *name) 2380 { 2381 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2382 SYMLOOK_DLSYM); 2383 } 2384 2385 dlfunc_t 2386 dlfunc(void *handle, const char *name) 2387 { 2388 union { 2389 void *d; 2390 dlfunc_t f; 2391 } rv; 2392 2393 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2394 SYMLOOK_DLSYM); 2395 return (rv.f); 2396 } 2397 2398 void * 2399 dlvsym(void *handle, const char *name, const char *version) 2400 { 2401 Ver_Entry ventry; 2402 2403 ventry.name = version; 2404 ventry.file = NULL; 2405 ventry.hash = elf_hash(version); 2406 ventry.flags= 0; 2407 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2408 SYMLOOK_DLSYM); 2409 } 2410 2411 int 2412 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2413 { 2414 const Obj_Entry *obj; 2415 RtldLockState lockstate; 2416 2417 rlock_acquire(rtld_bind_lock, &lockstate); 2418 obj = obj_from_addr(addr); 2419 if (obj == NULL) { 2420 _rtld_error("No shared object contains address"); 2421 lock_release(rtld_bind_lock, &lockstate); 2422 return (0); 2423 } 2424 rtld_fill_dl_phdr_info(obj, phdr_info); 2425 lock_release(rtld_bind_lock, &lockstate); 2426 return (1); 2427 } 2428 2429 int 2430 dladdr(const void *addr, Dl_info *info) 2431 { 2432 const Obj_Entry *obj; 2433 const Elf_Sym *def; 2434 void *symbol_addr; 2435 unsigned long symoffset; 2436 RtldLockState lockstate; 2437 2438 rlock_acquire(rtld_bind_lock, &lockstate); 2439 obj = obj_from_addr(addr); 2440 if (obj == NULL) { 2441 _rtld_error("No shared object contains address"); 2442 lock_release(rtld_bind_lock, &lockstate); 2443 return 0; 2444 } 2445 info->dli_fname = obj->path; 2446 info->dli_fbase = obj->mapbase; 2447 info->dli_saddr = (void *)0; 2448 info->dli_sname = NULL; 2449 2450 /* 2451 * Walk the symbol list looking for the symbol whose address is 2452 * closest to the address sent in. 2453 */ 2454 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2455 def = obj->symtab + symoffset; 2456 2457 /* 2458 * For skip the symbol if st_shndx is either SHN_UNDEF or 2459 * SHN_COMMON. 2460 */ 2461 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2462 continue; 2463 2464 /* 2465 * If the symbol is greater than the specified address, or if it 2466 * is further away from addr than the current nearest symbol, 2467 * then reject it. 2468 */ 2469 symbol_addr = obj->relocbase + def->st_value; 2470 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2471 continue; 2472 2473 /* Update our idea of the nearest symbol. */ 2474 info->dli_sname = obj->strtab + def->st_name; 2475 info->dli_saddr = symbol_addr; 2476 2477 /* Exact match? */ 2478 if (info->dli_saddr == addr) 2479 break; 2480 } 2481 lock_release(rtld_bind_lock, &lockstate); 2482 return 1; 2483 } 2484 2485 int 2486 dlinfo(void *handle, int request, void *p) 2487 { 2488 const Obj_Entry *obj; 2489 RtldLockState lockstate; 2490 int error; 2491 2492 rlock_acquire(rtld_bind_lock, &lockstate); 2493 2494 if (handle == NULL || handle == RTLD_SELF) { 2495 void *retaddr; 2496 2497 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2498 if ((obj = obj_from_addr(retaddr)) == NULL) 2499 _rtld_error("Cannot determine caller's shared object"); 2500 } else 2501 obj = dlcheck(handle); 2502 2503 if (obj == NULL) { 2504 lock_release(rtld_bind_lock, &lockstate); 2505 return (-1); 2506 } 2507 2508 error = 0; 2509 switch (request) { 2510 case RTLD_DI_LINKMAP: 2511 *((struct link_map const **)p) = &obj->linkmap; 2512 break; 2513 case RTLD_DI_ORIGIN: 2514 error = rtld_dirname(obj->path, p); 2515 break; 2516 2517 case RTLD_DI_SERINFOSIZE: 2518 case RTLD_DI_SERINFO: 2519 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2520 break; 2521 2522 default: 2523 _rtld_error("Invalid request %d passed to dlinfo()", request); 2524 error = -1; 2525 } 2526 2527 lock_release(rtld_bind_lock, &lockstate); 2528 2529 return (error); 2530 } 2531 2532 static void 2533 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2534 { 2535 2536 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2537 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2538 STAILQ_FIRST(&obj->names)->name : obj->path; 2539 phdr_info->dlpi_phdr = obj->phdr; 2540 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2541 phdr_info->dlpi_tls_modid = obj->tlsindex; 2542 phdr_info->dlpi_tls_data = obj->tlsinit; 2543 phdr_info->dlpi_adds = obj_loads; 2544 phdr_info->dlpi_subs = obj_loads - obj_count; 2545 } 2546 2547 int 2548 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2549 { 2550 struct dl_phdr_info phdr_info; 2551 const Obj_Entry *obj; 2552 RtldLockState bind_lockstate, phdr_lockstate; 2553 int error; 2554 2555 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2556 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2557 2558 error = 0; 2559 2560 for (obj = obj_list; obj != NULL; obj = obj->next) { 2561 rtld_fill_dl_phdr_info(obj, &phdr_info); 2562 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2563 break; 2564 2565 } 2566 lock_release(rtld_bind_lock, &bind_lockstate); 2567 lock_release(rtld_phdr_lock, &phdr_lockstate); 2568 2569 return (error); 2570 } 2571 2572 struct fill_search_info_args { 2573 int request; 2574 unsigned int flags; 2575 Dl_serinfo *serinfo; 2576 Dl_serpath *serpath; 2577 char *strspace; 2578 }; 2579 2580 static void * 2581 fill_search_info(const char *dir, size_t dirlen, void *param) 2582 { 2583 struct fill_search_info_args *arg; 2584 2585 arg = param; 2586 2587 if (arg->request == RTLD_DI_SERINFOSIZE) { 2588 arg->serinfo->dls_cnt ++; 2589 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2590 } else { 2591 struct dl_serpath *s_entry; 2592 2593 s_entry = arg->serpath; 2594 s_entry->dls_name = arg->strspace; 2595 s_entry->dls_flags = arg->flags; 2596 2597 strncpy(arg->strspace, dir, dirlen); 2598 arg->strspace[dirlen] = '\0'; 2599 2600 arg->strspace += dirlen + 1; 2601 arg->serpath++; 2602 } 2603 2604 return (NULL); 2605 } 2606 2607 static int 2608 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2609 { 2610 struct dl_serinfo _info; 2611 struct fill_search_info_args args; 2612 2613 args.request = RTLD_DI_SERINFOSIZE; 2614 args.serinfo = &_info; 2615 2616 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2617 _info.dls_cnt = 0; 2618 2619 path_enumerate(ld_library_path, fill_search_info, &args); 2620 path_enumerate(obj->rpath, fill_search_info, &args); 2621 path_enumerate(gethints(), fill_search_info, &args); 2622 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2623 2624 2625 if (request == RTLD_DI_SERINFOSIZE) { 2626 info->dls_size = _info.dls_size; 2627 info->dls_cnt = _info.dls_cnt; 2628 return (0); 2629 } 2630 2631 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2632 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2633 return (-1); 2634 } 2635 2636 args.request = RTLD_DI_SERINFO; 2637 args.serinfo = info; 2638 args.serpath = &info->dls_serpath[0]; 2639 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2640 2641 args.flags = LA_SER_LIBPATH; 2642 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2643 return (-1); 2644 2645 args.flags = LA_SER_RUNPATH; 2646 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2647 return (-1); 2648 2649 args.flags = LA_SER_CONFIG; 2650 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2651 return (-1); 2652 2653 args.flags = LA_SER_DEFAULT; 2654 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2655 return (-1); 2656 return (0); 2657 } 2658 2659 static int 2660 rtld_dirname(const char *path, char *bname) 2661 { 2662 const char *endp; 2663 2664 /* Empty or NULL string gets treated as "." */ 2665 if (path == NULL || *path == '\0') { 2666 bname[0] = '.'; 2667 bname[1] = '\0'; 2668 return (0); 2669 } 2670 2671 /* Strip trailing slashes */ 2672 endp = path + strlen(path) - 1; 2673 while (endp > path && *endp == '/') 2674 endp--; 2675 2676 /* Find the start of the dir */ 2677 while (endp > path && *endp != '/') 2678 endp--; 2679 2680 /* Either the dir is "/" or there are no slashes */ 2681 if (endp == path) { 2682 bname[0] = *endp == '/' ? '/' : '.'; 2683 bname[1] = '\0'; 2684 return (0); 2685 } else { 2686 do { 2687 endp--; 2688 } while (endp > path && *endp == '/'); 2689 } 2690 2691 if (endp - path + 2 > PATH_MAX) 2692 { 2693 _rtld_error("Filename is too long: %s", path); 2694 return(-1); 2695 } 2696 2697 strncpy(bname, path, endp - path + 1); 2698 bname[endp - path + 1] = '\0'; 2699 return (0); 2700 } 2701 2702 static int 2703 rtld_dirname_abs(const char *path, char *base) 2704 { 2705 char base_rel[PATH_MAX]; 2706 2707 if (rtld_dirname(path, base) == -1) 2708 return (-1); 2709 if (base[0] == '/') 2710 return (0); 2711 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2712 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2713 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2714 return (-1); 2715 strcpy(base, base_rel); 2716 return (0); 2717 } 2718 2719 static void 2720 linkmap_add(Obj_Entry *obj) 2721 { 2722 struct link_map *l = &obj->linkmap; 2723 struct link_map *prev; 2724 2725 obj->linkmap.l_name = obj->path; 2726 obj->linkmap.l_addr = obj->mapbase; 2727 obj->linkmap.l_ld = obj->dynamic; 2728 #ifdef __mips__ 2729 /* GDB needs load offset on MIPS to use the symbols */ 2730 obj->linkmap.l_offs = obj->relocbase; 2731 #endif 2732 2733 if (r_debug.r_map == NULL) { 2734 r_debug.r_map = l; 2735 return; 2736 } 2737 2738 /* 2739 * Scan to the end of the list, but not past the entry for the 2740 * dynamic linker, which we want to keep at the very end. 2741 */ 2742 for (prev = r_debug.r_map; 2743 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2744 prev = prev->l_next) 2745 ; 2746 2747 /* Link in the new entry. */ 2748 l->l_prev = prev; 2749 l->l_next = prev->l_next; 2750 if (l->l_next != NULL) 2751 l->l_next->l_prev = l; 2752 prev->l_next = l; 2753 } 2754 2755 static void 2756 linkmap_delete(Obj_Entry *obj) 2757 { 2758 struct link_map *l = &obj->linkmap; 2759 2760 if (l->l_prev == NULL) { 2761 if ((r_debug.r_map = l->l_next) != NULL) 2762 l->l_next->l_prev = NULL; 2763 return; 2764 } 2765 2766 if ((l->l_prev->l_next = l->l_next) != NULL) 2767 l->l_next->l_prev = l->l_prev; 2768 } 2769 2770 /* 2771 * Function for the debugger to set a breakpoint on to gain control. 2772 * 2773 * The two parameters allow the debugger to easily find and determine 2774 * what the runtime loader is doing and to whom it is doing it. 2775 * 2776 * When the loadhook trap is hit (r_debug_state, set at program 2777 * initialization), the arguments can be found on the stack: 2778 * 2779 * +8 struct link_map *m 2780 * +4 struct r_debug *rd 2781 * +0 RetAddr 2782 */ 2783 void 2784 r_debug_state(struct r_debug* rd, struct link_map *m) 2785 { 2786 } 2787 2788 /* 2789 * Get address of the pointer variable in the main program. 2790 * Prefer non-weak symbol over the weak one. 2791 */ 2792 static const void ** 2793 get_program_var_addr(const char *name, RtldLockState *lockstate) 2794 { 2795 SymLook req; 2796 DoneList donelist; 2797 2798 symlook_init(&req, name); 2799 req.lockstate = lockstate; 2800 donelist_init(&donelist); 2801 if (symlook_global(&req, &donelist) != 0) 2802 return (NULL); 2803 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 2804 return ((const void **)make_function_pointer(req.sym_out, 2805 req.defobj_out)); 2806 else 2807 return ((const void **)(req.defobj_out->relocbase + 2808 req.sym_out->st_value)); 2809 } 2810 2811 /* 2812 * Set a pointer variable in the main program to the given value. This 2813 * is used to set key variables such as "environ" before any of the 2814 * init functions are called. 2815 */ 2816 static void 2817 set_program_var(const char *name, const void *value) 2818 { 2819 const void **addr; 2820 2821 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 2822 dbg("\"%s\": *%p <-- %p", name, addr, value); 2823 *addr = value; 2824 } 2825 } 2826 2827 /* 2828 * Search the global objects, including dependencies and main object, 2829 * for the given symbol. 2830 */ 2831 static int 2832 symlook_global(SymLook *req, DoneList *donelist) 2833 { 2834 SymLook req1; 2835 const Objlist_Entry *elm; 2836 int res; 2837 2838 symlook_init_from_req(&req1, req); 2839 2840 /* Search all objects loaded at program start up. */ 2841 if (req->defobj_out == NULL || 2842 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2843 res = symlook_list(&req1, &list_main, donelist); 2844 if (res == 0 && (req->defobj_out == NULL || 2845 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2846 req->sym_out = req1.sym_out; 2847 req->defobj_out = req1.defobj_out; 2848 assert(req->defobj_out != NULL); 2849 } 2850 } 2851 2852 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2853 STAILQ_FOREACH(elm, &list_global, link) { 2854 if (req->defobj_out != NULL && 2855 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2856 break; 2857 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 2858 if (res == 0 && (req->defobj_out == NULL || 2859 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2860 req->sym_out = req1.sym_out; 2861 req->defobj_out = req1.defobj_out; 2862 assert(req->defobj_out != NULL); 2863 } 2864 } 2865 2866 return (req->sym_out != NULL ? 0 : ESRCH); 2867 } 2868 2869 /* 2870 * Given a symbol name in a referencing object, find the corresponding 2871 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2872 * no definition was found. Returns a pointer to the Obj_Entry of the 2873 * defining object via the reference parameter DEFOBJ_OUT. 2874 */ 2875 static int 2876 symlook_default(SymLook *req, const Obj_Entry *refobj) 2877 { 2878 DoneList donelist; 2879 const Objlist_Entry *elm; 2880 SymLook req1; 2881 int res; 2882 2883 donelist_init(&donelist); 2884 symlook_init_from_req(&req1, req); 2885 2886 /* Look first in the referencing object if linked symbolically. */ 2887 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2888 res = symlook_obj(&req1, refobj); 2889 if (res == 0) { 2890 req->sym_out = req1.sym_out; 2891 req->defobj_out = req1.defobj_out; 2892 assert(req->defobj_out != NULL); 2893 } 2894 } 2895 2896 symlook_global(req, &donelist); 2897 2898 /* Search all dlopened DAGs containing the referencing object. */ 2899 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2900 if (req->sym_out != NULL && 2901 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2902 break; 2903 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 2904 if (res == 0 && (req->sym_out == NULL || 2905 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2906 req->sym_out = req1.sym_out; 2907 req->defobj_out = req1.defobj_out; 2908 assert(req->defobj_out != NULL); 2909 } 2910 } 2911 2912 /* 2913 * Search the dynamic linker itself, and possibly resolve the 2914 * symbol from there. This is how the application links to 2915 * dynamic linker services such as dlopen. 2916 */ 2917 if (req->sym_out == NULL || 2918 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2919 res = symlook_obj(&req1, &obj_rtld); 2920 if (res == 0) { 2921 req->sym_out = req1.sym_out; 2922 req->defobj_out = req1.defobj_out; 2923 assert(req->defobj_out != NULL); 2924 } 2925 } 2926 2927 return (req->sym_out != NULL ? 0 : ESRCH); 2928 } 2929 2930 static int 2931 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 2932 { 2933 const Elf_Sym *def; 2934 const Obj_Entry *defobj; 2935 const Objlist_Entry *elm; 2936 SymLook req1; 2937 int res; 2938 2939 def = NULL; 2940 defobj = NULL; 2941 STAILQ_FOREACH(elm, objlist, link) { 2942 if (donelist_check(dlp, elm->obj)) 2943 continue; 2944 symlook_init_from_req(&req1, req); 2945 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 2946 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 2947 def = req1.sym_out; 2948 defobj = req1.defobj_out; 2949 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2950 break; 2951 } 2952 } 2953 } 2954 if (def != NULL) { 2955 req->sym_out = def; 2956 req->defobj_out = defobj; 2957 return (0); 2958 } 2959 return (ESRCH); 2960 } 2961 2962 /* 2963 * Search the chain of DAGS cointed to by the given Needed_Entry 2964 * for a symbol of the given name. Each DAG is scanned completely 2965 * before advancing to the next one. Returns a pointer to the symbol, 2966 * or NULL if no definition was found. 2967 */ 2968 static int 2969 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 2970 { 2971 const Elf_Sym *def; 2972 const Needed_Entry *n; 2973 const Obj_Entry *defobj; 2974 SymLook req1; 2975 int res; 2976 2977 def = NULL; 2978 defobj = NULL; 2979 symlook_init_from_req(&req1, req); 2980 for (n = needed; n != NULL; n = n->next) { 2981 if (n->obj == NULL || 2982 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 2983 continue; 2984 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 2985 def = req1.sym_out; 2986 defobj = req1.defobj_out; 2987 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2988 break; 2989 } 2990 } 2991 if (def != NULL) { 2992 req->sym_out = def; 2993 req->defobj_out = defobj; 2994 return (0); 2995 } 2996 return (ESRCH); 2997 } 2998 2999 /* 3000 * Search the symbol table of a single shared object for a symbol of 3001 * the given name and version, if requested. Returns a pointer to the 3002 * symbol, or NULL if no definition was found. If the object is 3003 * filter, return filtered symbol from filtee. 3004 * 3005 * The symbol's hash value is passed in for efficiency reasons; that 3006 * eliminates many recomputations of the hash value. 3007 */ 3008 int 3009 symlook_obj(SymLook *req, const Obj_Entry *obj) 3010 { 3011 DoneList donelist; 3012 SymLook req1; 3013 int res, mres; 3014 3015 mres = symlook_obj1(req, obj); 3016 if (mres == 0) { 3017 if (obj->needed_filtees != NULL) { 3018 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3019 donelist_init(&donelist); 3020 symlook_init_from_req(&req1, req); 3021 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3022 if (res == 0) { 3023 req->sym_out = req1.sym_out; 3024 req->defobj_out = req1.defobj_out; 3025 } 3026 return (res); 3027 } 3028 if (obj->needed_aux_filtees != NULL) { 3029 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3030 donelist_init(&donelist); 3031 symlook_init_from_req(&req1, req); 3032 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3033 if (res == 0) { 3034 req->sym_out = req1.sym_out; 3035 req->defobj_out = req1.defobj_out; 3036 return (res); 3037 } 3038 } 3039 } 3040 return (mres); 3041 } 3042 3043 static int 3044 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3045 { 3046 unsigned long symnum; 3047 const Elf_Sym *vsymp; 3048 Elf_Versym verndx; 3049 int vcount; 3050 3051 if (obj->buckets == NULL) 3052 return (ESRCH); 3053 3054 vsymp = NULL; 3055 vcount = 0; 3056 symnum = obj->buckets[req->hash % obj->nbuckets]; 3057 3058 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3059 const Elf_Sym *symp; 3060 const char *strp; 3061 3062 if (symnum >= obj->nchains) 3063 return (ESRCH); /* Bad object */ 3064 3065 symp = obj->symtab + symnum; 3066 strp = obj->strtab + symp->st_name; 3067 3068 switch (ELF_ST_TYPE(symp->st_info)) { 3069 case STT_FUNC: 3070 case STT_NOTYPE: 3071 case STT_OBJECT: 3072 if (symp->st_value == 0) 3073 continue; 3074 /* fallthrough */ 3075 case STT_TLS: 3076 if (symp->st_shndx != SHN_UNDEF) 3077 break; 3078 #ifndef __mips__ 3079 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3080 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3081 break; 3082 /* fallthrough */ 3083 #endif 3084 default: 3085 continue; 3086 } 3087 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3088 continue; 3089 3090 if (req->ventry == NULL) { 3091 if (obj->versyms != NULL) { 3092 verndx = VER_NDX(obj->versyms[symnum]); 3093 if (verndx > obj->vernum) { 3094 _rtld_error("%s: symbol %s references wrong version %d", 3095 obj->path, obj->strtab + symnum, verndx); 3096 continue; 3097 } 3098 /* 3099 * If we are not called from dlsym (i.e. this is a normal 3100 * relocation from unversioned binary), accept the symbol 3101 * immediately if it happens to have first version after 3102 * this shared object became versioned. Otherwise, if 3103 * symbol is versioned and not hidden, remember it. If it 3104 * is the only symbol with this name exported by the 3105 * shared object, it will be returned as a match at the 3106 * end of the function. If symbol is global (verndx < 2) 3107 * accept it unconditionally. 3108 */ 3109 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3110 verndx == VER_NDX_GIVEN) { 3111 req->sym_out = symp; 3112 req->defobj_out = obj; 3113 return (0); 3114 } 3115 else if (verndx >= VER_NDX_GIVEN) { 3116 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3117 if (vsymp == NULL) 3118 vsymp = symp; 3119 vcount ++; 3120 } 3121 continue; 3122 } 3123 } 3124 req->sym_out = symp; 3125 req->defobj_out = obj; 3126 return (0); 3127 } else { 3128 if (obj->versyms == NULL) { 3129 if (object_match_name(obj, req->ventry->name)) { 3130 _rtld_error("%s: object %s should provide version %s for " 3131 "symbol %s", obj_rtld.path, obj->path, 3132 req->ventry->name, obj->strtab + symnum); 3133 continue; 3134 } 3135 } else { 3136 verndx = VER_NDX(obj->versyms[symnum]); 3137 if (verndx > obj->vernum) { 3138 _rtld_error("%s: symbol %s references wrong version %d", 3139 obj->path, obj->strtab + symnum, verndx); 3140 continue; 3141 } 3142 if (obj->vertab[verndx].hash != req->ventry->hash || 3143 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3144 /* 3145 * Version does not match. Look if this is a global symbol 3146 * and if it is not hidden. If global symbol (verndx < 2) 3147 * is available, use it. Do not return symbol if we are 3148 * called by dlvsym, because dlvsym looks for a specific 3149 * version and default one is not what dlvsym wants. 3150 */ 3151 if ((req->flags & SYMLOOK_DLSYM) || 3152 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3153 (verndx >= VER_NDX_GIVEN)) 3154 continue; 3155 } 3156 } 3157 req->sym_out = symp; 3158 req->defobj_out = obj; 3159 return (0); 3160 } 3161 } 3162 if (vcount == 1) { 3163 req->sym_out = vsymp; 3164 req->defobj_out = obj; 3165 return (0); 3166 } 3167 return (ESRCH); 3168 } 3169 3170 static void 3171 trace_loaded_objects(Obj_Entry *obj) 3172 { 3173 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3174 int c; 3175 3176 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3177 main_local = ""; 3178 3179 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3180 fmt1 = "\t%o => %p (%x)\n"; 3181 3182 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3183 fmt2 = "\t%o (%x)\n"; 3184 3185 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3186 3187 for (; obj; obj = obj->next) { 3188 Needed_Entry *needed; 3189 char *name, *path; 3190 bool is_lib; 3191 3192 if (list_containers && obj->needed != NULL) 3193 printf("%s:\n", obj->path); 3194 for (needed = obj->needed; needed; needed = needed->next) { 3195 if (needed->obj != NULL) { 3196 if (needed->obj->traced && !list_containers) 3197 continue; 3198 needed->obj->traced = true; 3199 path = needed->obj->path; 3200 } else 3201 path = "not found"; 3202 3203 name = (char *)obj->strtab + needed->name; 3204 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3205 3206 fmt = is_lib ? fmt1 : fmt2; 3207 while ((c = *fmt++) != '\0') { 3208 switch (c) { 3209 default: 3210 putchar(c); 3211 continue; 3212 case '\\': 3213 switch (c = *fmt) { 3214 case '\0': 3215 continue; 3216 case 'n': 3217 putchar('\n'); 3218 break; 3219 case 't': 3220 putchar('\t'); 3221 break; 3222 } 3223 break; 3224 case '%': 3225 switch (c = *fmt) { 3226 case '\0': 3227 continue; 3228 case '%': 3229 default: 3230 putchar(c); 3231 break; 3232 case 'A': 3233 printf("%s", main_local); 3234 break; 3235 case 'a': 3236 printf("%s", obj_main->path); 3237 break; 3238 case 'o': 3239 printf("%s", name); 3240 break; 3241 #if 0 3242 case 'm': 3243 printf("%d", sodp->sod_major); 3244 break; 3245 case 'n': 3246 printf("%d", sodp->sod_minor); 3247 break; 3248 #endif 3249 case 'p': 3250 printf("%s", path); 3251 break; 3252 case 'x': 3253 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3254 break; 3255 } 3256 break; 3257 } 3258 ++fmt; 3259 } 3260 } 3261 } 3262 } 3263 3264 /* 3265 * Unload a dlopened object and its dependencies from memory and from 3266 * our data structures. It is assumed that the DAG rooted in the 3267 * object has already been unreferenced, and that the object has a 3268 * reference count of 0. 3269 */ 3270 static void 3271 unload_object(Obj_Entry *root) 3272 { 3273 Obj_Entry *obj; 3274 Obj_Entry **linkp; 3275 3276 assert(root->refcount == 0); 3277 3278 /* 3279 * Pass over the DAG removing unreferenced objects from 3280 * appropriate lists. 3281 */ 3282 unlink_object(root); 3283 3284 /* Unmap all objects that are no longer referenced. */ 3285 linkp = &obj_list->next; 3286 while ((obj = *linkp) != NULL) { 3287 if (obj->refcount == 0) { 3288 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3289 obj->path); 3290 dbg("unloading \"%s\"", obj->path); 3291 unload_filtees(root); 3292 munmap(obj->mapbase, obj->mapsize); 3293 linkmap_delete(obj); 3294 *linkp = obj->next; 3295 obj_count--; 3296 obj_free(obj); 3297 } else 3298 linkp = &obj->next; 3299 } 3300 obj_tail = linkp; 3301 } 3302 3303 static void 3304 unlink_object(Obj_Entry *root) 3305 { 3306 Objlist_Entry *elm; 3307 3308 if (root->refcount == 0) { 3309 /* Remove the object from the RTLD_GLOBAL list. */ 3310 objlist_remove(&list_global, root); 3311 3312 /* Remove the object from all objects' DAG lists. */ 3313 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3314 objlist_remove(&elm->obj->dldags, root); 3315 if (elm->obj != root) 3316 unlink_object(elm->obj); 3317 } 3318 } 3319 } 3320 3321 static void 3322 ref_dag(Obj_Entry *root) 3323 { 3324 Objlist_Entry *elm; 3325 3326 assert(root->dag_inited); 3327 STAILQ_FOREACH(elm, &root->dagmembers, link) 3328 elm->obj->refcount++; 3329 } 3330 3331 static void 3332 unref_dag(Obj_Entry *root) 3333 { 3334 Objlist_Entry *elm; 3335 3336 assert(root->dag_inited); 3337 STAILQ_FOREACH(elm, &root->dagmembers, link) 3338 elm->obj->refcount--; 3339 } 3340 3341 /* 3342 * Common code for MD __tls_get_addr(). 3343 */ 3344 void * 3345 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3346 { 3347 Elf_Addr* dtv = *dtvp; 3348 RtldLockState lockstate; 3349 3350 /* Check dtv generation in case new modules have arrived */ 3351 if (dtv[0] != tls_dtv_generation) { 3352 Elf_Addr* newdtv; 3353 int to_copy; 3354 3355 wlock_acquire(rtld_bind_lock, &lockstate); 3356 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3357 to_copy = dtv[1]; 3358 if (to_copy > tls_max_index) 3359 to_copy = tls_max_index; 3360 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3361 newdtv[0] = tls_dtv_generation; 3362 newdtv[1] = tls_max_index; 3363 free(dtv); 3364 lock_release(rtld_bind_lock, &lockstate); 3365 *dtvp = newdtv; 3366 } 3367 3368 /* Dynamically allocate module TLS if necessary */ 3369 if (!dtv[index + 1]) { 3370 /* Signal safe, wlock will block out signals. */ 3371 wlock_acquire(rtld_bind_lock, &lockstate); 3372 if (!dtv[index + 1]) 3373 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3374 lock_release(rtld_bind_lock, &lockstate); 3375 } 3376 return (void*) (dtv[index + 1] + offset); 3377 } 3378 3379 /* XXX not sure what variants to use for arm. */ 3380 3381 #if defined(__ia64__) || defined(__powerpc__) 3382 3383 /* 3384 * Allocate Static TLS using the Variant I method. 3385 */ 3386 void * 3387 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3388 { 3389 Obj_Entry *obj; 3390 char *tcb; 3391 Elf_Addr **tls; 3392 Elf_Addr *dtv; 3393 Elf_Addr addr; 3394 int i; 3395 3396 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3397 return (oldtcb); 3398 3399 assert(tcbsize >= TLS_TCB_SIZE); 3400 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3401 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3402 3403 if (oldtcb != NULL) { 3404 memcpy(tls, oldtcb, tls_static_space); 3405 free(oldtcb); 3406 3407 /* Adjust the DTV. */ 3408 dtv = tls[0]; 3409 for (i = 0; i < dtv[1]; i++) { 3410 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3411 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3412 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3413 } 3414 } 3415 } else { 3416 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3417 tls[0] = dtv; 3418 dtv[0] = tls_dtv_generation; 3419 dtv[1] = tls_max_index; 3420 3421 for (obj = objs; obj; obj = obj->next) { 3422 if (obj->tlsoffset > 0) { 3423 addr = (Elf_Addr)tls + obj->tlsoffset; 3424 if (obj->tlsinitsize > 0) 3425 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3426 if (obj->tlssize > obj->tlsinitsize) 3427 memset((void*) (addr + obj->tlsinitsize), 0, 3428 obj->tlssize - obj->tlsinitsize); 3429 dtv[obj->tlsindex + 1] = addr; 3430 } 3431 } 3432 } 3433 3434 return (tcb); 3435 } 3436 3437 void 3438 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3439 { 3440 Elf_Addr *dtv; 3441 Elf_Addr tlsstart, tlsend; 3442 int dtvsize, i; 3443 3444 assert(tcbsize >= TLS_TCB_SIZE); 3445 3446 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3447 tlsend = tlsstart + tls_static_space; 3448 3449 dtv = *(Elf_Addr **)tlsstart; 3450 dtvsize = dtv[1]; 3451 for (i = 0; i < dtvsize; i++) { 3452 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3453 free((void*)dtv[i+2]); 3454 } 3455 } 3456 free(dtv); 3457 free(tcb); 3458 } 3459 3460 #endif 3461 3462 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3463 defined(__arm__) || defined(__mips__) 3464 3465 /* 3466 * Allocate Static TLS using the Variant II method. 3467 */ 3468 void * 3469 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3470 { 3471 Obj_Entry *obj; 3472 size_t size; 3473 char *tls; 3474 Elf_Addr *dtv, *olddtv; 3475 Elf_Addr segbase, oldsegbase, addr; 3476 int i; 3477 3478 size = round(tls_static_space, tcbalign); 3479 3480 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3481 tls = calloc(1, size + tcbsize); 3482 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3483 3484 segbase = (Elf_Addr)(tls + size); 3485 ((Elf_Addr*)segbase)[0] = segbase; 3486 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3487 3488 dtv[0] = tls_dtv_generation; 3489 dtv[1] = tls_max_index; 3490 3491 if (oldtls) { 3492 /* 3493 * Copy the static TLS block over whole. 3494 */ 3495 oldsegbase = (Elf_Addr) oldtls; 3496 memcpy((void *)(segbase - tls_static_space), 3497 (const void *)(oldsegbase - tls_static_space), 3498 tls_static_space); 3499 3500 /* 3501 * If any dynamic TLS blocks have been created tls_get_addr(), 3502 * move them over. 3503 */ 3504 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3505 for (i = 0; i < olddtv[1]; i++) { 3506 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3507 dtv[i+2] = olddtv[i+2]; 3508 olddtv[i+2] = 0; 3509 } 3510 } 3511 3512 /* 3513 * We assume that this block was the one we created with 3514 * allocate_initial_tls(). 3515 */ 3516 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3517 } else { 3518 for (obj = objs; obj; obj = obj->next) { 3519 if (obj->tlsoffset) { 3520 addr = segbase - obj->tlsoffset; 3521 memset((void*) (addr + obj->tlsinitsize), 3522 0, obj->tlssize - obj->tlsinitsize); 3523 if (obj->tlsinit) 3524 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3525 dtv[obj->tlsindex + 1] = addr; 3526 } 3527 } 3528 } 3529 3530 return (void*) segbase; 3531 } 3532 3533 void 3534 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3535 { 3536 size_t size; 3537 Elf_Addr* dtv; 3538 int dtvsize, i; 3539 Elf_Addr tlsstart, tlsend; 3540 3541 /* 3542 * Figure out the size of the initial TLS block so that we can 3543 * find stuff which ___tls_get_addr() allocated dynamically. 3544 */ 3545 size = round(tls_static_space, tcbalign); 3546 3547 dtv = ((Elf_Addr**)tls)[1]; 3548 dtvsize = dtv[1]; 3549 tlsend = (Elf_Addr) tls; 3550 tlsstart = tlsend - size; 3551 for (i = 0; i < dtvsize; i++) { 3552 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3553 free((void*) dtv[i+2]); 3554 } 3555 } 3556 3557 free((void*) tlsstart); 3558 free((void*) dtv); 3559 } 3560 3561 #endif 3562 3563 /* 3564 * Allocate TLS block for module with given index. 3565 */ 3566 void * 3567 allocate_module_tls(int index) 3568 { 3569 Obj_Entry* obj; 3570 char* p; 3571 3572 for (obj = obj_list; obj; obj = obj->next) { 3573 if (obj->tlsindex == index) 3574 break; 3575 } 3576 if (!obj) { 3577 _rtld_error("Can't find module with TLS index %d", index); 3578 die(); 3579 } 3580 3581 p = malloc(obj->tlssize); 3582 if (p == NULL) { 3583 _rtld_error("Cannot allocate TLS block for index %d", index); 3584 die(); 3585 } 3586 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3587 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3588 3589 return p; 3590 } 3591 3592 bool 3593 allocate_tls_offset(Obj_Entry *obj) 3594 { 3595 size_t off; 3596 3597 if (obj->tls_done) 3598 return true; 3599 3600 if (obj->tlssize == 0) { 3601 obj->tls_done = true; 3602 return true; 3603 } 3604 3605 if (obj->tlsindex == 1) 3606 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3607 else 3608 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3609 obj->tlssize, obj->tlsalign); 3610 3611 /* 3612 * If we have already fixed the size of the static TLS block, we 3613 * must stay within that size. When allocating the static TLS, we 3614 * leave a small amount of space spare to be used for dynamically 3615 * loading modules which use static TLS. 3616 */ 3617 if (tls_static_space) { 3618 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3619 return false; 3620 } 3621 3622 tls_last_offset = obj->tlsoffset = off; 3623 tls_last_size = obj->tlssize; 3624 obj->tls_done = true; 3625 3626 return true; 3627 } 3628 3629 void 3630 free_tls_offset(Obj_Entry *obj) 3631 { 3632 3633 /* 3634 * If we were the last thing to allocate out of the static TLS 3635 * block, we give our space back to the 'allocator'. This is a 3636 * simplistic workaround to allow libGL.so.1 to be loaded and 3637 * unloaded multiple times. 3638 */ 3639 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3640 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3641 tls_last_offset -= obj->tlssize; 3642 tls_last_size = 0; 3643 } 3644 } 3645 3646 void * 3647 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3648 { 3649 void *ret; 3650 RtldLockState lockstate; 3651 3652 wlock_acquire(rtld_bind_lock, &lockstate); 3653 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3654 lock_release(rtld_bind_lock, &lockstate); 3655 return (ret); 3656 } 3657 3658 void 3659 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3660 { 3661 RtldLockState lockstate; 3662 3663 wlock_acquire(rtld_bind_lock, &lockstate); 3664 free_tls(tcb, tcbsize, tcbalign); 3665 lock_release(rtld_bind_lock, &lockstate); 3666 } 3667 3668 static void 3669 object_add_name(Obj_Entry *obj, const char *name) 3670 { 3671 Name_Entry *entry; 3672 size_t len; 3673 3674 len = strlen(name); 3675 entry = malloc(sizeof(Name_Entry) + len); 3676 3677 if (entry != NULL) { 3678 strcpy(entry->name, name); 3679 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3680 } 3681 } 3682 3683 static int 3684 object_match_name(const Obj_Entry *obj, const char *name) 3685 { 3686 Name_Entry *entry; 3687 3688 STAILQ_FOREACH(entry, &obj->names, link) { 3689 if (strcmp(name, entry->name) == 0) 3690 return (1); 3691 } 3692 return (0); 3693 } 3694 3695 static Obj_Entry * 3696 locate_dependency(const Obj_Entry *obj, const char *name) 3697 { 3698 const Objlist_Entry *entry; 3699 const Needed_Entry *needed; 3700 3701 STAILQ_FOREACH(entry, &list_main, link) { 3702 if (object_match_name(entry->obj, name)) 3703 return entry->obj; 3704 } 3705 3706 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3707 if (strcmp(obj->strtab + needed->name, name) == 0 || 3708 (needed->obj != NULL && object_match_name(needed->obj, name))) { 3709 /* 3710 * If there is DT_NEEDED for the name we are looking for, 3711 * we are all set. Note that object might not be found if 3712 * dependency was not loaded yet, so the function can 3713 * return NULL here. This is expected and handled 3714 * properly by the caller. 3715 */ 3716 return (needed->obj); 3717 } 3718 } 3719 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3720 obj->path, name); 3721 die(); 3722 } 3723 3724 static int 3725 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3726 const Elf_Vernaux *vna) 3727 { 3728 const Elf_Verdef *vd; 3729 const char *vername; 3730 3731 vername = refobj->strtab + vna->vna_name; 3732 vd = depobj->verdef; 3733 if (vd == NULL) { 3734 _rtld_error("%s: version %s required by %s not defined", 3735 depobj->path, vername, refobj->path); 3736 return (-1); 3737 } 3738 for (;;) { 3739 if (vd->vd_version != VER_DEF_CURRENT) { 3740 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3741 depobj->path, vd->vd_version); 3742 return (-1); 3743 } 3744 if (vna->vna_hash == vd->vd_hash) { 3745 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3746 ((char *)vd + vd->vd_aux); 3747 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3748 return (0); 3749 } 3750 if (vd->vd_next == 0) 3751 break; 3752 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3753 } 3754 if (vna->vna_flags & VER_FLG_WEAK) 3755 return (0); 3756 _rtld_error("%s: version %s required by %s not found", 3757 depobj->path, vername, refobj->path); 3758 return (-1); 3759 } 3760 3761 static int 3762 rtld_verify_object_versions(Obj_Entry *obj) 3763 { 3764 const Elf_Verneed *vn; 3765 const Elf_Verdef *vd; 3766 const Elf_Verdaux *vda; 3767 const Elf_Vernaux *vna; 3768 const Obj_Entry *depobj; 3769 int maxvernum, vernum; 3770 3771 maxvernum = 0; 3772 /* 3773 * Walk over defined and required version records and figure out 3774 * max index used by any of them. Do very basic sanity checking 3775 * while there. 3776 */ 3777 vn = obj->verneed; 3778 while (vn != NULL) { 3779 if (vn->vn_version != VER_NEED_CURRENT) { 3780 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3781 obj->path, vn->vn_version); 3782 return (-1); 3783 } 3784 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3785 for (;;) { 3786 vernum = VER_NEED_IDX(vna->vna_other); 3787 if (vernum > maxvernum) 3788 maxvernum = vernum; 3789 if (vna->vna_next == 0) 3790 break; 3791 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3792 } 3793 if (vn->vn_next == 0) 3794 break; 3795 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3796 } 3797 3798 vd = obj->verdef; 3799 while (vd != NULL) { 3800 if (vd->vd_version != VER_DEF_CURRENT) { 3801 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3802 obj->path, vd->vd_version); 3803 return (-1); 3804 } 3805 vernum = VER_DEF_IDX(vd->vd_ndx); 3806 if (vernum > maxvernum) 3807 maxvernum = vernum; 3808 if (vd->vd_next == 0) 3809 break; 3810 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3811 } 3812 3813 if (maxvernum == 0) 3814 return (0); 3815 3816 /* 3817 * Store version information in array indexable by version index. 3818 * Verify that object version requirements are satisfied along the 3819 * way. 3820 */ 3821 obj->vernum = maxvernum + 1; 3822 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3823 3824 vd = obj->verdef; 3825 while (vd != NULL) { 3826 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3827 vernum = VER_DEF_IDX(vd->vd_ndx); 3828 assert(vernum <= maxvernum); 3829 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3830 obj->vertab[vernum].hash = vd->vd_hash; 3831 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3832 obj->vertab[vernum].file = NULL; 3833 obj->vertab[vernum].flags = 0; 3834 } 3835 if (vd->vd_next == 0) 3836 break; 3837 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3838 } 3839 3840 vn = obj->verneed; 3841 while (vn != NULL) { 3842 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3843 if (depobj == NULL) 3844 return (-1); 3845 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3846 for (;;) { 3847 if (check_object_provided_version(obj, depobj, vna)) 3848 return (-1); 3849 vernum = VER_NEED_IDX(vna->vna_other); 3850 assert(vernum <= maxvernum); 3851 obj->vertab[vernum].hash = vna->vna_hash; 3852 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3853 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3854 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3855 VER_INFO_HIDDEN : 0; 3856 if (vna->vna_next == 0) 3857 break; 3858 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3859 } 3860 if (vn->vn_next == 0) 3861 break; 3862 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3863 } 3864 return 0; 3865 } 3866 3867 static int 3868 rtld_verify_versions(const Objlist *objlist) 3869 { 3870 Objlist_Entry *entry; 3871 int rc; 3872 3873 rc = 0; 3874 STAILQ_FOREACH(entry, objlist, link) { 3875 /* 3876 * Skip dummy objects or objects that have their version requirements 3877 * already checked. 3878 */ 3879 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3880 continue; 3881 if (rtld_verify_object_versions(entry->obj) == -1) { 3882 rc = -1; 3883 if (ld_tracing == NULL) 3884 break; 3885 } 3886 } 3887 if (rc == 0 || ld_tracing != NULL) 3888 rc = rtld_verify_object_versions(&obj_rtld); 3889 return rc; 3890 } 3891 3892 const Ver_Entry * 3893 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3894 { 3895 Elf_Versym vernum; 3896 3897 if (obj->vertab) { 3898 vernum = VER_NDX(obj->versyms[symnum]); 3899 if (vernum >= obj->vernum) { 3900 _rtld_error("%s: symbol %s has wrong verneed value %d", 3901 obj->path, obj->strtab + symnum, vernum); 3902 } else if (obj->vertab[vernum].hash != 0) { 3903 return &obj->vertab[vernum]; 3904 } 3905 } 3906 return NULL; 3907 } 3908 3909 int 3910 _rtld_get_stack_prot(void) 3911 { 3912 3913 return (stack_prot); 3914 } 3915 3916 static void 3917 map_stacks_exec(RtldLockState *lockstate) 3918 { 3919 void (*thr_map_stacks_exec)(void); 3920 3921 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 3922 return; 3923 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 3924 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 3925 if (thr_map_stacks_exec != NULL) { 3926 stack_prot |= PROT_EXEC; 3927 thr_map_stacks_exec(); 3928 } 3929 } 3930 3931 void 3932 symlook_init(SymLook *dst, const char *name) 3933 { 3934 3935 bzero(dst, sizeof(*dst)); 3936 dst->name = name; 3937 dst->hash = elf_hash(name); 3938 } 3939 3940 static void 3941 symlook_init_from_req(SymLook *dst, const SymLook *src) 3942 { 3943 3944 dst->name = src->name; 3945 dst->hash = src->hash; 3946 dst->ventry = src->ventry; 3947 dst->flags = src->flags; 3948 dst->defobj_out = NULL; 3949 dst->sym_out = NULL; 3950 dst->lockstate = src->lockstate; 3951 } 3952 3953 /* 3954 * Overrides for libc_pic-provided functions. 3955 */ 3956 3957 int 3958 __getosreldate(void) 3959 { 3960 size_t len; 3961 int oid[2]; 3962 int error, osrel; 3963 3964 if (osreldate != 0) 3965 return (osreldate); 3966 3967 oid[0] = CTL_KERN; 3968 oid[1] = KERN_OSRELDATE; 3969 osrel = 0; 3970 len = sizeof(osrel); 3971 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 3972 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 3973 osreldate = osrel; 3974 return (osreldate); 3975 } 3976 3977 /* 3978 * No unresolved symbols for rtld. 3979 */ 3980 void 3981 __pthread_cxa_finalize(struct dl_phdr_info *a) 3982 { 3983 } 3984