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 break; 1639 if (obj != NULL) { 1640 object_add_name(obj, name); 1641 free(path); 1642 close(fd); 1643 return obj; 1644 } 1645 if (flags & RTLD_LO_NOLOAD) { 1646 free(path); 1647 return (NULL); 1648 } 1649 1650 /* First use of this object, so we must map it in */ 1651 obj = do_load_object(fd, name, path, &sb, flags); 1652 if (obj == NULL) 1653 free(path); 1654 close(fd); 1655 1656 return obj; 1657 } 1658 1659 static Obj_Entry * 1660 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1661 int flags) 1662 { 1663 Obj_Entry *obj; 1664 struct statfs fs; 1665 1666 /* 1667 * but first, make sure that environment variables haven't been 1668 * used to circumvent the noexec flag on a filesystem. 1669 */ 1670 if (dangerous_ld_env) { 1671 if (fstatfs(fd, &fs) != 0) { 1672 _rtld_error("Cannot fstatfs \"%s\"", path); 1673 return NULL; 1674 } 1675 if (fs.f_flags & MNT_NOEXEC) { 1676 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1677 return NULL; 1678 } 1679 } 1680 dbg("loading \"%s\"", path); 1681 obj = map_object(fd, path, sbp); 1682 if (obj == NULL) 1683 return NULL; 1684 1685 object_add_name(obj, name); 1686 obj->path = path; 1687 digest_dynamic(obj, 0); 1688 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1689 RTLD_LO_DLOPEN) { 1690 dbg("refusing to load non-loadable \"%s\"", obj->path); 1691 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1692 munmap(obj->mapbase, obj->mapsize); 1693 obj_free(obj); 1694 return (NULL); 1695 } 1696 1697 *obj_tail = obj; 1698 obj_tail = &obj->next; 1699 obj_count++; 1700 obj_loads++; 1701 linkmap_add(obj); /* for GDB & dlinfo() */ 1702 max_stack_flags |= obj->stack_flags; 1703 1704 dbg(" %p .. %p: %s", obj->mapbase, 1705 obj->mapbase + obj->mapsize - 1, obj->path); 1706 if (obj->textrel) 1707 dbg(" WARNING: %s has impure text", obj->path); 1708 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1709 obj->path); 1710 1711 return obj; 1712 } 1713 1714 static Obj_Entry * 1715 obj_from_addr(const void *addr) 1716 { 1717 Obj_Entry *obj; 1718 1719 for (obj = obj_list; obj != NULL; obj = obj->next) { 1720 if (addr < (void *) obj->mapbase) 1721 continue; 1722 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1723 return obj; 1724 } 1725 return NULL; 1726 } 1727 1728 /* 1729 * Call the finalization functions for each of the objects in "list" 1730 * belonging to the DAG of "root" and referenced once. If NULL "root" 1731 * is specified, every finalization function will be called regardless 1732 * of the reference count and the list elements won't be freed. All of 1733 * the objects are expected to have non-NULL fini functions. 1734 */ 1735 static void 1736 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1737 { 1738 Objlist_Entry *elm; 1739 char *saved_msg; 1740 1741 assert(root == NULL || root->refcount == 1); 1742 1743 /* 1744 * Preserve the current error message since a fini function might 1745 * call into the dynamic linker and overwrite it. 1746 */ 1747 saved_msg = errmsg_save(); 1748 do { 1749 STAILQ_FOREACH(elm, list, link) { 1750 if (root != NULL && (elm->obj->refcount != 1 || 1751 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1752 continue; 1753 dbg("calling fini function for %s at %p", elm->obj->path, 1754 (void *)elm->obj->fini); 1755 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1756 elm->obj->path); 1757 /* Remove object from fini list to prevent recursive invocation. */ 1758 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1759 /* 1760 * XXX: If a dlopen() call references an object while the 1761 * fini function is in progress, we might end up trying to 1762 * unload the referenced object in dlclose() or the object 1763 * won't be unloaded although its fini function has been 1764 * called. 1765 */ 1766 lock_release(rtld_bind_lock, lockstate); 1767 call_initfini_pointer(elm->obj, elm->obj->fini); 1768 wlock_acquire(rtld_bind_lock, lockstate); 1769 /* No need to free anything if process is going down. */ 1770 if (root != NULL) 1771 free(elm); 1772 /* 1773 * We must restart the list traversal after every fini call 1774 * because a dlclose() call from the fini function or from 1775 * another thread might have modified the reference counts. 1776 */ 1777 break; 1778 } 1779 } while (elm != NULL); 1780 errmsg_restore(saved_msg); 1781 } 1782 1783 /* 1784 * Call the initialization functions for each of the objects in 1785 * "list". All of the objects are expected to have non-NULL init 1786 * functions. 1787 */ 1788 static void 1789 objlist_call_init(Objlist *list, RtldLockState *lockstate) 1790 { 1791 Objlist_Entry *elm; 1792 Obj_Entry *obj; 1793 char *saved_msg; 1794 1795 /* 1796 * Clean init_scanned flag so that objects can be rechecked and 1797 * possibly initialized earlier if any of vectors called below 1798 * cause the change by using dlopen. 1799 */ 1800 for (obj = obj_list; obj != NULL; obj = obj->next) 1801 obj->init_scanned = false; 1802 1803 /* 1804 * Preserve the current error message since an init function might 1805 * call into the dynamic linker and overwrite it. 1806 */ 1807 saved_msg = errmsg_save(); 1808 STAILQ_FOREACH(elm, list, link) { 1809 if (elm->obj->init_done) /* Initialized early. */ 1810 continue; 1811 dbg("calling init function for %s at %p", elm->obj->path, 1812 (void *)elm->obj->init); 1813 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1814 elm->obj->path); 1815 /* 1816 * Race: other thread might try to use this object before current 1817 * one completes the initilization. Not much can be done here 1818 * without better locking. 1819 */ 1820 elm->obj->init_done = true; 1821 lock_release(rtld_bind_lock, lockstate); 1822 call_initfini_pointer(elm->obj, elm->obj->init); 1823 wlock_acquire(rtld_bind_lock, lockstate); 1824 } 1825 errmsg_restore(saved_msg); 1826 } 1827 1828 static void 1829 objlist_clear(Objlist *list) 1830 { 1831 Objlist_Entry *elm; 1832 1833 while (!STAILQ_EMPTY(list)) { 1834 elm = STAILQ_FIRST(list); 1835 STAILQ_REMOVE_HEAD(list, link); 1836 free(elm); 1837 } 1838 } 1839 1840 static Objlist_Entry * 1841 objlist_find(Objlist *list, const Obj_Entry *obj) 1842 { 1843 Objlist_Entry *elm; 1844 1845 STAILQ_FOREACH(elm, list, link) 1846 if (elm->obj == obj) 1847 return elm; 1848 return NULL; 1849 } 1850 1851 static void 1852 objlist_init(Objlist *list) 1853 { 1854 STAILQ_INIT(list); 1855 } 1856 1857 static void 1858 objlist_push_head(Objlist *list, Obj_Entry *obj) 1859 { 1860 Objlist_Entry *elm; 1861 1862 elm = NEW(Objlist_Entry); 1863 elm->obj = obj; 1864 STAILQ_INSERT_HEAD(list, elm, link); 1865 } 1866 1867 static void 1868 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1869 { 1870 Objlist_Entry *elm; 1871 1872 elm = NEW(Objlist_Entry); 1873 elm->obj = obj; 1874 STAILQ_INSERT_TAIL(list, elm, link); 1875 } 1876 1877 static void 1878 objlist_remove(Objlist *list, Obj_Entry *obj) 1879 { 1880 Objlist_Entry *elm; 1881 1882 if ((elm = objlist_find(list, obj)) != NULL) { 1883 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1884 free(elm); 1885 } 1886 } 1887 1888 /* 1889 * Relocate newly-loaded shared objects. The argument is a pointer to 1890 * the Obj_Entry for the first such object. All objects from the first 1891 * to the end of the list of objects are relocated. Returns 0 on success, 1892 * or -1 on failure. 1893 */ 1894 static int 1895 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 1896 RtldLockState *lockstate) 1897 { 1898 Obj_Entry *obj; 1899 1900 for (obj = first; obj != NULL; obj = obj->next) { 1901 if (obj != rtldobj) 1902 dbg("relocating \"%s\"", obj->path); 1903 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1904 obj->symtab == NULL || obj->strtab == NULL) { 1905 _rtld_error("%s: Shared object has no run-time symbol table", 1906 obj->path); 1907 return -1; 1908 } 1909 1910 if (obj->textrel) { 1911 /* There are relocations to the write-protected text segment. */ 1912 if (mprotect(obj->mapbase, obj->textsize, 1913 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1914 _rtld_error("%s: Cannot write-enable text segment: %s", 1915 obj->path, strerror(errno)); 1916 return -1; 1917 } 1918 } 1919 1920 /* Process the non-PLT relocations. */ 1921 if (reloc_non_plt(obj, rtldobj, lockstate)) 1922 return -1; 1923 1924 if (obj->textrel) { /* Re-protected the text segment. */ 1925 if (mprotect(obj->mapbase, obj->textsize, 1926 PROT_READ|PROT_EXEC) == -1) { 1927 _rtld_error("%s: Cannot write-protect text segment: %s", 1928 obj->path, strerror(errno)); 1929 return -1; 1930 } 1931 } 1932 1933 /* Process the PLT relocations. */ 1934 if (reloc_plt(obj) == -1) 1935 return -1; 1936 /* Relocate the jump slots if we are doing immediate binding. */ 1937 if (obj->bind_now || bind_now) 1938 if (reloc_jmpslots(obj, lockstate) == -1) 1939 return -1; 1940 1941 1942 /* 1943 * Set up the magic number and version in the Obj_Entry. These 1944 * were checked in the crt1.o from the original ElfKit, so we 1945 * set them for backward compatibility. 1946 */ 1947 obj->magic = RTLD_MAGIC; 1948 obj->version = RTLD_VERSION; 1949 1950 /* Set the special PLT or GOT entries. */ 1951 init_pltgot(obj); 1952 } 1953 1954 return 0; 1955 } 1956 1957 /* 1958 * Cleanup procedure. It will be called (by the atexit mechanism) just 1959 * before the process exits. 1960 */ 1961 static void 1962 rtld_exit(void) 1963 { 1964 RtldLockState lockstate; 1965 1966 wlock_acquire(rtld_bind_lock, &lockstate); 1967 dbg("rtld_exit()"); 1968 objlist_call_fini(&list_fini, NULL, &lockstate); 1969 /* No need to remove the items from the list, since we are exiting. */ 1970 if (!libmap_disable) 1971 lm_fini(); 1972 lock_release(rtld_bind_lock, &lockstate); 1973 } 1974 1975 static void * 1976 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1977 { 1978 #ifdef COMPAT_32BIT 1979 const char *trans; 1980 #endif 1981 if (path == NULL) 1982 return (NULL); 1983 1984 path += strspn(path, ":;"); 1985 while (*path != '\0') { 1986 size_t len; 1987 char *res; 1988 1989 len = strcspn(path, ":;"); 1990 #ifdef COMPAT_32BIT 1991 trans = lm_findn(NULL, path, len); 1992 if (trans) 1993 res = callback(trans, strlen(trans), arg); 1994 else 1995 #endif 1996 res = callback(path, len, arg); 1997 1998 if (res != NULL) 1999 return (res); 2000 2001 path += len; 2002 path += strspn(path, ":;"); 2003 } 2004 2005 return (NULL); 2006 } 2007 2008 struct try_library_args { 2009 const char *name; 2010 size_t namelen; 2011 char *buffer; 2012 size_t buflen; 2013 }; 2014 2015 static void * 2016 try_library_path(const char *dir, size_t dirlen, void *param) 2017 { 2018 struct try_library_args *arg; 2019 2020 arg = param; 2021 if (*dir == '/' || trust) { 2022 char *pathname; 2023 2024 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2025 return (NULL); 2026 2027 pathname = arg->buffer; 2028 strncpy(pathname, dir, dirlen); 2029 pathname[dirlen] = '/'; 2030 strcpy(pathname + dirlen + 1, arg->name); 2031 2032 dbg(" Trying \"%s\"", pathname); 2033 if (access(pathname, F_OK) == 0) { /* We found it */ 2034 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2035 strcpy(pathname, arg->buffer); 2036 return (pathname); 2037 } 2038 } 2039 return (NULL); 2040 } 2041 2042 static char * 2043 search_library_path(const char *name, const char *path) 2044 { 2045 char *p; 2046 struct try_library_args arg; 2047 2048 if (path == NULL) 2049 return NULL; 2050 2051 arg.name = name; 2052 arg.namelen = strlen(name); 2053 arg.buffer = xmalloc(PATH_MAX); 2054 arg.buflen = PATH_MAX; 2055 2056 p = path_enumerate(path, try_library_path, &arg); 2057 2058 free(arg.buffer); 2059 2060 return (p); 2061 } 2062 2063 int 2064 dlclose(void *handle) 2065 { 2066 Obj_Entry *root; 2067 RtldLockState lockstate; 2068 2069 wlock_acquire(rtld_bind_lock, &lockstate); 2070 root = dlcheck(handle); 2071 if (root == NULL) { 2072 lock_release(rtld_bind_lock, &lockstate); 2073 return -1; 2074 } 2075 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2076 root->path); 2077 2078 /* Unreference the object and its dependencies. */ 2079 root->dl_refcount--; 2080 2081 if (root->refcount == 1) { 2082 /* 2083 * The object will be no longer referenced, so we must unload it. 2084 * First, call the fini functions. 2085 */ 2086 objlist_call_fini(&list_fini, root, &lockstate); 2087 2088 unref_dag(root); 2089 2090 /* Finish cleaning up the newly-unreferenced objects. */ 2091 GDB_STATE(RT_DELETE,&root->linkmap); 2092 unload_object(root); 2093 GDB_STATE(RT_CONSISTENT,NULL); 2094 } else 2095 unref_dag(root); 2096 2097 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2098 lock_release(rtld_bind_lock, &lockstate); 2099 return 0; 2100 } 2101 2102 char * 2103 dlerror(void) 2104 { 2105 char *msg = error_message; 2106 error_message = NULL; 2107 return msg; 2108 } 2109 2110 /* 2111 * This function is deprecated and has no effect. 2112 */ 2113 void 2114 dllockinit(void *context, 2115 void *(*lock_create)(void *context), 2116 void (*rlock_acquire)(void *lock), 2117 void (*wlock_acquire)(void *lock), 2118 void (*lock_release)(void *lock), 2119 void (*lock_destroy)(void *lock), 2120 void (*context_destroy)(void *context)) 2121 { 2122 static void *cur_context; 2123 static void (*cur_context_destroy)(void *); 2124 2125 /* Just destroy the context from the previous call, if necessary. */ 2126 if (cur_context_destroy != NULL) 2127 cur_context_destroy(cur_context); 2128 cur_context = context; 2129 cur_context_destroy = context_destroy; 2130 } 2131 2132 void * 2133 dlopen(const char *name, int mode) 2134 { 2135 RtldLockState lockstate; 2136 int lo_flags; 2137 2138 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2139 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2140 if (ld_tracing != NULL) { 2141 rlock_acquire(rtld_bind_lock, &lockstate); 2142 if (sigsetjmp(lockstate.env, 0) != 0) 2143 lock_upgrade(rtld_bind_lock, &lockstate); 2144 environ = (char **)*get_program_var_addr("environ", &lockstate); 2145 lock_release(rtld_bind_lock, &lockstate); 2146 } 2147 lo_flags = RTLD_LO_DLOPEN; 2148 if (mode & RTLD_NODELETE) 2149 lo_flags |= RTLD_LO_NODELETE; 2150 if (mode & RTLD_NOLOAD) 2151 lo_flags |= RTLD_LO_NOLOAD; 2152 if (ld_tracing != NULL) 2153 lo_flags |= RTLD_LO_TRACE; 2154 2155 return (dlopen_object(name, obj_main, lo_flags, 2156 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2157 } 2158 2159 static Obj_Entry * 2160 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode) 2161 { 2162 Obj_Entry **old_obj_tail; 2163 Obj_Entry *obj; 2164 Objlist initlist; 2165 RtldLockState lockstate; 2166 int result; 2167 2168 objlist_init(&initlist); 2169 2170 wlock_acquire(rtld_bind_lock, &lockstate); 2171 GDB_STATE(RT_ADD,NULL); 2172 2173 old_obj_tail = obj_tail; 2174 obj = NULL; 2175 if (name == NULL) { 2176 obj = obj_main; 2177 obj->refcount++; 2178 } else { 2179 obj = load_object(name, refobj, lo_flags); 2180 } 2181 2182 if (obj) { 2183 obj->dl_refcount++; 2184 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2185 objlist_push_tail(&list_global, obj); 2186 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2187 assert(*old_obj_tail == obj); 2188 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN); 2189 init_dag(obj); 2190 ref_dag(obj); 2191 if (result != -1) 2192 result = rtld_verify_versions(&obj->dagmembers); 2193 if (result != -1 && ld_tracing) 2194 goto trace; 2195 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK) 2196 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) { 2197 obj->dl_refcount--; 2198 unref_dag(obj); 2199 if (obj->refcount == 0) 2200 unload_object(obj); 2201 obj = NULL; 2202 } else { 2203 /* Make list of init functions to call. */ 2204 initlist_add_objects(obj, &obj->next, &initlist); 2205 } 2206 } else { 2207 2208 /* 2209 * Bump the reference counts for objects on this DAG. If 2210 * this is the first dlopen() call for the object that was 2211 * already loaded as a dependency, initialize the dag 2212 * starting at it. 2213 */ 2214 init_dag(obj); 2215 ref_dag(obj); 2216 2217 if ((lo_flags & RTLD_LO_TRACE) != 0) 2218 goto trace; 2219 } 2220 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2221 obj->z_nodelete) && !obj->ref_nodel) { 2222 dbg("obj %s nodelete", obj->path); 2223 ref_dag(obj); 2224 obj->z_nodelete = obj->ref_nodel = true; 2225 } 2226 } 2227 2228 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2229 name); 2230 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2231 2232 map_stacks_exec(&lockstate); 2233 2234 /* Call the init functions. */ 2235 objlist_call_init(&initlist, &lockstate); 2236 objlist_clear(&initlist); 2237 lock_release(rtld_bind_lock, &lockstate); 2238 return obj; 2239 trace: 2240 trace_loaded_objects(obj); 2241 lock_release(rtld_bind_lock, &lockstate); 2242 exit(0); 2243 } 2244 2245 static void * 2246 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2247 int flags) 2248 { 2249 DoneList donelist; 2250 const Obj_Entry *obj, *defobj; 2251 const Elf_Sym *def; 2252 SymLook req; 2253 RtldLockState lockstate; 2254 int res; 2255 2256 def = NULL; 2257 defobj = NULL; 2258 symlook_init(&req, name); 2259 req.ventry = ve; 2260 req.flags = flags | SYMLOOK_IN_PLT; 2261 req.lockstate = &lockstate; 2262 2263 rlock_acquire(rtld_bind_lock, &lockstate); 2264 if (sigsetjmp(lockstate.env, 0) != 0) 2265 lock_upgrade(rtld_bind_lock, &lockstate); 2266 if (handle == NULL || handle == RTLD_NEXT || 2267 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2268 2269 if ((obj = obj_from_addr(retaddr)) == NULL) { 2270 _rtld_error("Cannot determine caller's shared object"); 2271 lock_release(rtld_bind_lock, &lockstate); 2272 return NULL; 2273 } 2274 if (handle == NULL) { /* Just the caller's shared object. */ 2275 res = symlook_obj(&req, obj); 2276 if (res == 0) { 2277 def = req.sym_out; 2278 defobj = req.defobj_out; 2279 } 2280 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2281 handle == RTLD_SELF) { /* ... caller included */ 2282 if (handle == RTLD_NEXT) 2283 obj = obj->next; 2284 for (; obj != NULL; obj = obj->next) { 2285 res = symlook_obj(&req, obj); 2286 if (res == 0) { 2287 if (def == NULL || 2288 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2289 def = req.sym_out; 2290 defobj = req.defobj_out; 2291 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2292 break; 2293 } 2294 } 2295 } 2296 /* 2297 * Search the dynamic linker itself, and possibly resolve the 2298 * symbol from there. This is how the application links to 2299 * dynamic linker services such as dlopen. 2300 */ 2301 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2302 res = symlook_obj(&req, &obj_rtld); 2303 if (res == 0) { 2304 def = req.sym_out; 2305 defobj = req.defobj_out; 2306 } 2307 } 2308 } else { 2309 assert(handle == RTLD_DEFAULT); 2310 res = symlook_default(&req, obj); 2311 if (res == 0) { 2312 defobj = req.defobj_out; 2313 def = req.sym_out; 2314 } 2315 } 2316 } else { 2317 if ((obj = dlcheck(handle)) == NULL) { 2318 lock_release(rtld_bind_lock, &lockstate); 2319 return NULL; 2320 } 2321 2322 donelist_init(&donelist); 2323 if (obj->mainprog) { 2324 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2325 res = symlook_global(&req, &donelist); 2326 if (res == 0) { 2327 def = req.sym_out; 2328 defobj = req.defobj_out; 2329 } 2330 /* 2331 * Search the dynamic linker itself, and possibly resolve the 2332 * symbol from there. This is how the application links to 2333 * dynamic linker services such as dlopen. 2334 */ 2335 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2336 res = symlook_obj(&req, &obj_rtld); 2337 if (res == 0) { 2338 def = req.sym_out; 2339 defobj = req.defobj_out; 2340 } 2341 } 2342 } 2343 else { 2344 /* Search the whole DAG rooted at the given object. */ 2345 res = symlook_list(&req, &obj->dagmembers, &donelist); 2346 if (res == 0) { 2347 def = req.sym_out; 2348 defobj = req.defobj_out; 2349 } 2350 } 2351 } 2352 2353 if (def != NULL) { 2354 lock_release(rtld_bind_lock, &lockstate); 2355 2356 /* 2357 * The value required by the caller is derived from the value 2358 * of the symbol. For the ia64 architecture, we need to 2359 * construct a function descriptor which the caller can use to 2360 * call the function with the right 'gp' value. For other 2361 * architectures and for non-functions, the value is simply 2362 * the relocated value of the symbol. 2363 */ 2364 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2365 return make_function_pointer(def, defobj); 2366 else 2367 return defobj->relocbase + def->st_value; 2368 } 2369 2370 _rtld_error("Undefined symbol \"%s\"", name); 2371 lock_release(rtld_bind_lock, &lockstate); 2372 return NULL; 2373 } 2374 2375 void * 2376 dlsym(void *handle, const char *name) 2377 { 2378 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2379 SYMLOOK_DLSYM); 2380 } 2381 2382 dlfunc_t 2383 dlfunc(void *handle, const char *name) 2384 { 2385 union { 2386 void *d; 2387 dlfunc_t f; 2388 } rv; 2389 2390 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2391 SYMLOOK_DLSYM); 2392 return (rv.f); 2393 } 2394 2395 void * 2396 dlvsym(void *handle, const char *name, const char *version) 2397 { 2398 Ver_Entry ventry; 2399 2400 ventry.name = version; 2401 ventry.file = NULL; 2402 ventry.hash = elf_hash(version); 2403 ventry.flags= 0; 2404 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2405 SYMLOOK_DLSYM); 2406 } 2407 2408 int 2409 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2410 { 2411 const Obj_Entry *obj; 2412 RtldLockState lockstate; 2413 2414 rlock_acquire(rtld_bind_lock, &lockstate); 2415 obj = obj_from_addr(addr); 2416 if (obj == NULL) { 2417 _rtld_error("No shared object contains address"); 2418 lock_release(rtld_bind_lock, &lockstate); 2419 return (0); 2420 } 2421 rtld_fill_dl_phdr_info(obj, phdr_info); 2422 lock_release(rtld_bind_lock, &lockstate); 2423 return (1); 2424 } 2425 2426 int 2427 dladdr(const void *addr, Dl_info *info) 2428 { 2429 const Obj_Entry *obj; 2430 const Elf_Sym *def; 2431 void *symbol_addr; 2432 unsigned long symoffset; 2433 RtldLockState lockstate; 2434 2435 rlock_acquire(rtld_bind_lock, &lockstate); 2436 obj = obj_from_addr(addr); 2437 if (obj == NULL) { 2438 _rtld_error("No shared object contains address"); 2439 lock_release(rtld_bind_lock, &lockstate); 2440 return 0; 2441 } 2442 info->dli_fname = obj->path; 2443 info->dli_fbase = obj->mapbase; 2444 info->dli_saddr = (void *)0; 2445 info->dli_sname = NULL; 2446 2447 /* 2448 * Walk the symbol list looking for the symbol whose address is 2449 * closest to the address sent in. 2450 */ 2451 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2452 def = obj->symtab + symoffset; 2453 2454 /* 2455 * For skip the symbol if st_shndx is either SHN_UNDEF or 2456 * SHN_COMMON. 2457 */ 2458 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2459 continue; 2460 2461 /* 2462 * If the symbol is greater than the specified address, or if it 2463 * is further away from addr than the current nearest symbol, 2464 * then reject it. 2465 */ 2466 symbol_addr = obj->relocbase + def->st_value; 2467 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2468 continue; 2469 2470 /* Update our idea of the nearest symbol. */ 2471 info->dli_sname = obj->strtab + def->st_name; 2472 info->dli_saddr = symbol_addr; 2473 2474 /* Exact match? */ 2475 if (info->dli_saddr == addr) 2476 break; 2477 } 2478 lock_release(rtld_bind_lock, &lockstate); 2479 return 1; 2480 } 2481 2482 int 2483 dlinfo(void *handle, int request, void *p) 2484 { 2485 const Obj_Entry *obj; 2486 RtldLockState lockstate; 2487 int error; 2488 2489 rlock_acquire(rtld_bind_lock, &lockstate); 2490 2491 if (handle == NULL || handle == RTLD_SELF) { 2492 void *retaddr; 2493 2494 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2495 if ((obj = obj_from_addr(retaddr)) == NULL) 2496 _rtld_error("Cannot determine caller's shared object"); 2497 } else 2498 obj = dlcheck(handle); 2499 2500 if (obj == NULL) { 2501 lock_release(rtld_bind_lock, &lockstate); 2502 return (-1); 2503 } 2504 2505 error = 0; 2506 switch (request) { 2507 case RTLD_DI_LINKMAP: 2508 *((struct link_map const **)p) = &obj->linkmap; 2509 break; 2510 case RTLD_DI_ORIGIN: 2511 error = rtld_dirname(obj->path, p); 2512 break; 2513 2514 case RTLD_DI_SERINFOSIZE: 2515 case RTLD_DI_SERINFO: 2516 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2517 break; 2518 2519 default: 2520 _rtld_error("Invalid request %d passed to dlinfo()", request); 2521 error = -1; 2522 } 2523 2524 lock_release(rtld_bind_lock, &lockstate); 2525 2526 return (error); 2527 } 2528 2529 static void 2530 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2531 { 2532 2533 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2534 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2535 STAILQ_FIRST(&obj->names)->name : obj->path; 2536 phdr_info->dlpi_phdr = obj->phdr; 2537 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2538 phdr_info->dlpi_tls_modid = obj->tlsindex; 2539 phdr_info->dlpi_tls_data = obj->tlsinit; 2540 phdr_info->dlpi_adds = obj_loads; 2541 phdr_info->dlpi_subs = obj_loads - obj_count; 2542 } 2543 2544 int 2545 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2546 { 2547 struct dl_phdr_info phdr_info; 2548 const Obj_Entry *obj; 2549 RtldLockState bind_lockstate, phdr_lockstate; 2550 int error; 2551 2552 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2553 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2554 2555 error = 0; 2556 2557 for (obj = obj_list; obj != NULL; obj = obj->next) { 2558 rtld_fill_dl_phdr_info(obj, &phdr_info); 2559 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2560 break; 2561 2562 } 2563 lock_release(rtld_bind_lock, &bind_lockstate); 2564 lock_release(rtld_phdr_lock, &phdr_lockstate); 2565 2566 return (error); 2567 } 2568 2569 struct fill_search_info_args { 2570 int request; 2571 unsigned int flags; 2572 Dl_serinfo *serinfo; 2573 Dl_serpath *serpath; 2574 char *strspace; 2575 }; 2576 2577 static void * 2578 fill_search_info(const char *dir, size_t dirlen, void *param) 2579 { 2580 struct fill_search_info_args *arg; 2581 2582 arg = param; 2583 2584 if (arg->request == RTLD_DI_SERINFOSIZE) { 2585 arg->serinfo->dls_cnt ++; 2586 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2587 } else { 2588 struct dl_serpath *s_entry; 2589 2590 s_entry = arg->serpath; 2591 s_entry->dls_name = arg->strspace; 2592 s_entry->dls_flags = arg->flags; 2593 2594 strncpy(arg->strspace, dir, dirlen); 2595 arg->strspace[dirlen] = '\0'; 2596 2597 arg->strspace += dirlen + 1; 2598 arg->serpath++; 2599 } 2600 2601 return (NULL); 2602 } 2603 2604 static int 2605 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2606 { 2607 struct dl_serinfo _info; 2608 struct fill_search_info_args args; 2609 2610 args.request = RTLD_DI_SERINFOSIZE; 2611 args.serinfo = &_info; 2612 2613 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2614 _info.dls_cnt = 0; 2615 2616 path_enumerate(ld_library_path, fill_search_info, &args); 2617 path_enumerate(obj->rpath, fill_search_info, &args); 2618 path_enumerate(gethints(), fill_search_info, &args); 2619 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2620 2621 2622 if (request == RTLD_DI_SERINFOSIZE) { 2623 info->dls_size = _info.dls_size; 2624 info->dls_cnt = _info.dls_cnt; 2625 return (0); 2626 } 2627 2628 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2629 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2630 return (-1); 2631 } 2632 2633 args.request = RTLD_DI_SERINFO; 2634 args.serinfo = info; 2635 args.serpath = &info->dls_serpath[0]; 2636 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2637 2638 args.flags = LA_SER_LIBPATH; 2639 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2640 return (-1); 2641 2642 args.flags = LA_SER_RUNPATH; 2643 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2644 return (-1); 2645 2646 args.flags = LA_SER_CONFIG; 2647 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2648 return (-1); 2649 2650 args.flags = LA_SER_DEFAULT; 2651 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2652 return (-1); 2653 return (0); 2654 } 2655 2656 static int 2657 rtld_dirname(const char *path, char *bname) 2658 { 2659 const char *endp; 2660 2661 /* Empty or NULL string gets treated as "." */ 2662 if (path == NULL || *path == '\0') { 2663 bname[0] = '.'; 2664 bname[1] = '\0'; 2665 return (0); 2666 } 2667 2668 /* Strip trailing slashes */ 2669 endp = path + strlen(path) - 1; 2670 while (endp > path && *endp == '/') 2671 endp--; 2672 2673 /* Find the start of the dir */ 2674 while (endp > path && *endp != '/') 2675 endp--; 2676 2677 /* Either the dir is "/" or there are no slashes */ 2678 if (endp == path) { 2679 bname[0] = *endp == '/' ? '/' : '.'; 2680 bname[1] = '\0'; 2681 return (0); 2682 } else { 2683 do { 2684 endp--; 2685 } while (endp > path && *endp == '/'); 2686 } 2687 2688 if (endp - path + 2 > PATH_MAX) 2689 { 2690 _rtld_error("Filename is too long: %s", path); 2691 return(-1); 2692 } 2693 2694 strncpy(bname, path, endp - path + 1); 2695 bname[endp - path + 1] = '\0'; 2696 return (0); 2697 } 2698 2699 static int 2700 rtld_dirname_abs(const char *path, char *base) 2701 { 2702 char base_rel[PATH_MAX]; 2703 2704 if (rtld_dirname(path, base) == -1) 2705 return (-1); 2706 if (base[0] == '/') 2707 return (0); 2708 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2709 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2710 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2711 return (-1); 2712 strcpy(base, base_rel); 2713 return (0); 2714 } 2715 2716 static void 2717 linkmap_add(Obj_Entry *obj) 2718 { 2719 struct link_map *l = &obj->linkmap; 2720 struct link_map *prev; 2721 2722 obj->linkmap.l_name = obj->path; 2723 obj->linkmap.l_addr = obj->mapbase; 2724 obj->linkmap.l_ld = obj->dynamic; 2725 #ifdef __mips__ 2726 /* GDB needs load offset on MIPS to use the symbols */ 2727 obj->linkmap.l_offs = obj->relocbase; 2728 #endif 2729 2730 if (r_debug.r_map == NULL) { 2731 r_debug.r_map = l; 2732 return; 2733 } 2734 2735 /* 2736 * Scan to the end of the list, but not past the entry for the 2737 * dynamic linker, which we want to keep at the very end. 2738 */ 2739 for (prev = r_debug.r_map; 2740 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2741 prev = prev->l_next) 2742 ; 2743 2744 /* Link in the new entry. */ 2745 l->l_prev = prev; 2746 l->l_next = prev->l_next; 2747 if (l->l_next != NULL) 2748 l->l_next->l_prev = l; 2749 prev->l_next = l; 2750 } 2751 2752 static void 2753 linkmap_delete(Obj_Entry *obj) 2754 { 2755 struct link_map *l = &obj->linkmap; 2756 2757 if (l->l_prev == NULL) { 2758 if ((r_debug.r_map = l->l_next) != NULL) 2759 l->l_next->l_prev = NULL; 2760 return; 2761 } 2762 2763 if ((l->l_prev->l_next = l->l_next) != NULL) 2764 l->l_next->l_prev = l->l_prev; 2765 } 2766 2767 /* 2768 * Function for the debugger to set a breakpoint on to gain control. 2769 * 2770 * The two parameters allow the debugger to easily find and determine 2771 * what the runtime loader is doing and to whom it is doing it. 2772 * 2773 * When the loadhook trap is hit (r_debug_state, set at program 2774 * initialization), the arguments can be found on the stack: 2775 * 2776 * +8 struct link_map *m 2777 * +4 struct r_debug *rd 2778 * +0 RetAddr 2779 */ 2780 void 2781 r_debug_state(struct r_debug* rd, struct link_map *m) 2782 { 2783 } 2784 2785 /* 2786 * Get address of the pointer variable in the main program. 2787 * Prefer non-weak symbol over the weak one. 2788 */ 2789 static const void ** 2790 get_program_var_addr(const char *name, RtldLockState *lockstate) 2791 { 2792 SymLook req; 2793 DoneList donelist; 2794 2795 symlook_init(&req, name); 2796 req.lockstate = lockstate; 2797 donelist_init(&donelist); 2798 if (symlook_global(&req, &donelist) != 0) 2799 return (NULL); 2800 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 2801 return ((const void **)make_function_pointer(req.sym_out, 2802 req.defobj_out)); 2803 else 2804 return ((const void **)(req.defobj_out->relocbase + 2805 req.sym_out->st_value)); 2806 } 2807 2808 /* 2809 * Set a pointer variable in the main program to the given value. This 2810 * is used to set key variables such as "environ" before any of the 2811 * init functions are called. 2812 */ 2813 static void 2814 set_program_var(const char *name, const void *value) 2815 { 2816 const void **addr; 2817 2818 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 2819 dbg("\"%s\": *%p <-- %p", name, addr, value); 2820 *addr = value; 2821 } 2822 } 2823 2824 /* 2825 * Search the global objects, including dependencies and main object, 2826 * for the given symbol. 2827 */ 2828 static int 2829 symlook_global(SymLook *req, DoneList *donelist) 2830 { 2831 SymLook req1; 2832 const Objlist_Entry *elm; 2833 int res; 2834 2835 symlook_init_from_req(&req1, req); 2836 2837 /* Search all objects loaded at program start up. */ 2838 if (req->defobj_out == NULL || 2839 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2840 res = symlook_list(&req1, &list_main, donelist); 2841 if (res == 0 && (req->defobj_out == NULL || 2842 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2843 req->sym_out = req1.sym_out; 2844 req->defobj_out = req1.defobj_out; 2845 assert(req->defobj_out != NULL); 2846 } 2847 } 2848 2849 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2850 STAILQ_FOREACH(elm, &list_global, link) { 2851 if (req->defobj_out != NULL && 2852 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2853 break; 2854 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 2855 if (res == 0 && (req->defobj_out == NULL || 2856 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2857 req->sym_out = req1.sym_out; 2858 req->defobj_out = req1.defobj_out; 2859 assert(req->defobj_out != NULL); 2860 } 2861 } 2862 2863 return (req->sym_out != NULL ? 0 : ESRCH); 2864 } 2865 2866 /* 2867 * Given a symbol name in a referencing object, find the corresponding 2868 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2869 * no definition was found. Returns a pointer to the Obj_Entry of the 2870 * defining object via the reference parameter DEFOBJ_OUT. 2871 */ 2872 static int 2873 symlook_default(SymLook *req, const Obj_Entry *refobj) 2874 { 2875 DoneList donelist; 2876 const Objlist_Entry *elm; 2877 SymLook req1; 2878 int res; 2879 2880 donelist_init(&donelist); 2881 symlook_init_from_req(&req1, req); 2882 2883 /* Look first in the referencing object if linked symbolically. */ 2884 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2885 res = symlook_obj(&req1, refobj); 2886 if (res == 0) { 2887 req->sym_out = req1.sym_out; 2888 req->defobj_out = req1.defobj_out; 2889 assert(req->defobj_out != NULL); 2890 } 2891 } 2892 2893 symlook_global(req, &donelist); 2894 2895 /* Search all dlopened DAGs containing the referencing object. */ 2896 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2897 if (req->sym_out != NULL && 2898 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2899 break; 2900 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 2901 if (res == 0 && (req->sym_out == NULL || 2902 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2903 req->sym_out = req1.sym_out; 2904 req->defobj_out = req1.defobj_out; 2905 assert(req->defobj_out != NULL); 2906 } 2907 } 2908 2909 /* 2910 * Search the dynamic linker itself, and possibly resolve the 2911 * symbol from there. This is how the application links to 2912 * dynamic linker services such as dlopen. 2913 */ 2914 if (req->sym_out == NULL || 2915 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2916 res = symlook_obj(&req1, &obj_rtld); 2917 if (res == 0) { 2918 req->sym_out = req1.sym_out; 2919 req->defobj_out = req1.defobj_out; 2920 assert(req->defobj_out != NULL); 2921 } 2922 } 2923 2924 return (req->sym_out != NULL ? 0 : ESRCH); 2925 } 2926 2927 static int 2928 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 2929 { 2930 const Elf_Sym *def; 2931 const Obj_Entry *defobj; 2932 const Objlist_Entry *elm; 2933 SymLook req1; 2934 int res; 2935 2936 def = NULL; 2937 defobj = NULL; 2938 STAILQ_FOREACH(elm, objlist, link) { 2939 if (donelist_check(dlp, elm->obj)) 2940 continue; 2941 symlook_init_from_req(&req1, req); 2942 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 2943 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 2944 def = req1.sym_out; 2945 defobj = req1.defobj_out; 2946 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2947 break; 2948 } 2949 } 2950 } 2951 if (def != NULL) { 2952 req->sym_out = def; 2953 req->defobj_out = defobj; 2954 return (0); 2955 } 2956 return (ESRCH); 2957 } 2958 2959 /* 2960 * Search the chain of DAGS cointed to by the given Needed_Entry 2961 * for a symbol of the given name. Each DAG is scanned completely 2962 * before advancing to the next one. Returns a pointer to the symbol, 2963 * or NULL if no definition was found. 2964 */ 2965 static int 2966 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 2967 { 2968 const Elf_Sym *def; 2969 const Needed_Entry *n; 2970 const Obj_Entry *defobj; 2971 SymLook req1; 2972 int res; 2973 2974 def = NULL; 2975 defobj = NULL; 2976 symlook_init_from_req(&req1, req); 2977 for (n = needed; n != NULL; n = n->next) { 2978 if (n->obj == NULL || 2979 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 2980 continue; 2981 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 2982 def = req1.sym_out; 2983 defobj = req1.defobj_out; 2984 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2985 break; 2986 } 2987 } 2988 if (def != NULL) { 2989 req->sym_out = def; 2990 req->defobj_out = defobj; 2991 return (0); 2992 } 2993 return (ESRCH); 2994 } 2995 2996 /* 2997 * Search the symbol table of a single shared object for a symbol of 2998 * the given name and version, if requested. Returns a pointer to the 2999 * symbol, or NULL if no definition was found. If the object is 3000 * filter, return filtered symbol from filtee. 3001 * 3002 * The symbol's hash value is passed in for efficiency reasons; that 3003 * eliminates many recomputations of the hash value. 3004 */ 3005 int 3006 symlook_obj(SymLook *req, const Obj_Entry *obj) 3007 { 3008 DoneList donelist; 3009 SymLook req1; 3010 int res, mres; 3011 3012 mres = symlook_obj1(req, obj); 3013 if (mres == 0) { 3014 if (obj->needed_filtees != NULL) { 3015 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3016 donelist_init(&donelist); 3017 symlook_init_from_req(&req1, req); 3018 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3019 if (res == 0) { 3020 req->sym_out = req1.sym_out; 3021 req->defobj_out = req1.defobj_out; 3022 } 3023 return (res); 3024 } 3025 if (obj->needed_aux_filtees != NULL) { 3026 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3027 donelist_init(&donelist); 3028 symlook_init_from_req(&req1, req); 3029 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3030 if (res == 0) { 3031 req->sym_out = req1.sym_out; 3032 req->defobj_out = req1.defobj_out; 3033 return (res); 3034 } 3035 } 3036 } 3037 return (mres); 3038 } 3039 3040 static int 3041 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3042 { 3043 unsigned long symnum; 3044 const Elf_Sym *vsymp; 3045 Elf_Versym verndx; 3046 int vcount; 3047 3048 if (obj->buckets == NULL) 3049 return (ESRCH); 3050 3051 vsymp = NULL; 3052 vcount = 0; 3053 symnum = obj->buckets[req->hash % obj->nbuckets]; 3054 3055 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3056 const Elf_Sym *symp; 3057 const char *strp; 3058 3059 if (symnum >= obj->nchains) 3060 return (ESRCH); /* Bad object */ 3061 3062 symp = obj->symtab + symnum; 3063 strp = obj->strtab + symp->st_name; 3064 3065 switch (ELF_ST_TYPE(symp->st_info)) { 3066 case STT_FUNC: 3067 case STT_NOTYPE: 3068 case STT_OBJECT: 3069 if (symp->st_value == 0) 3070 continue; 3071 /* fallthrough */ 3072 case STT_TLS: 3073 if (symp->st_shndx != SHN_UNDEF) 3074 break; 3075 #ifndef __mips__ 3076 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3077 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3078 break; 3079 /* fallthrough */ 3080 #endif 3081 default: 3082 continue; 3083 } 3084 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3085 continue; 3086 3087 if (req->ventry == NULL) { 3088 if (obj->versyms != NULL) { 3089 verndx = VER_NDX(obj->versyms[symnum]); 3090 if (verndx > obj->vernum) { 3091 _rtld_error("%s: symbol %s references wrong version %d", 3092 obj->path, obj->strtab + symnum, verndx); 3093 continue; 3094 } 3095 /* 3096 * If we are not called from dlsym (i.e. this is a normal 3097 * relocation from unversioned binary), accept the symbol 3098 * immediately if it happens to have first version after 3099 * this shared object became versioned. Otherwise, if 3100 * symbol is versioned and not hidden, remember it. If it 3101 * is the only symbol with this name exported by the 3102 * shared object, it will be returned as a match at the 3103 * end of the function. If symbol is global (verndx < 2) 3104 * accept it unconditionally. 3105 */ 3106 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3107 verndx == VER_NDX_GIVEN) { 3108 req->sym_out = symp; 3109 req->defobj_out = obj; 3110 return (0); 3111 } 3112 else if (verndx >= VER_NDX_GIVEN) { 3113 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3114 if (vsymp == NULL) 3115 vsymp = symp; 3116 vcount ++; 3117 } 3118 continue; 3119 } 3120 } 3121 req->sym_out = symp; 3122 req->defobj_out = obj; 3123 return (0); 3124 } else { 3125 if (obj->versyms == NULL) { 3126 if (object_match_name(obj, req->ventry->name)) { 3127 _rtld_error("%s: object %s should provide version %s for " 3128 "symbol %s", obj_rtld.path, obj->path, 3129 req->ventry->name, obj->strtab + symnum); 3130 continue; 3131 } 3132 } else { 3133 verndx = VER_NDX(obj->versyms[symnum]); 3134 if (verndx > obj->vernum) { 3135 _rtld_error("%s: symbol %s references wrong version %d", 3136 obj->path, obj->strtab + symnum, verndx); 3137 continue; 3138 } 3139 if (obj->vertab[verndx].hash != req->ventry->hash || 3140 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3141 /* 3142 * Version does not match. Look if this is a global symbol 3143 * and if it is not hidden. If global symbol (verndx < 2) 3144 * is available, use it. Do not return symbol if we are 3145 * called by dlvsym, because dlvsym looks for a specific 3146 * version and default one is not what dlvsym wants. 3147 */ 3148 if ((req->flags & SYMLOOK_DLSYM) || 3149 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3150 (verndx >= VER_NDX_GIVEN)) 3151 continue; 3152 } 3153 } 3154 req->sym_out = symp; 3155 req->defobj_out = obj; 3156 return (0); 3157 } 3158 } 3159 if (vcount == 1) { 3160 req->sym_out = vsymp; 3161 req->defobj_out = obj; 3162 return (0); 3163 } 3164 return (ESRCH); 3165 } 3166 3167 static void 3168 trace_loaded_objects(Obj_Entry *obj) 3169 { 3170 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3171 int c; 3172 3173 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3174 main_local = ""; 3175 3176 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3177 fmt1 = "\t%o => %p (%x)\n"; 3178 3179 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3180 fmt2 = "\t%o (%x)\n"; 3181 3182 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3183 3184 for (; obj; obj = obj->next) { 3185 Needed_Entry *needed; 3186 char *name, *path; 3187 bool is_lib; 3188 3189 if (list_containers && obj->needed != NULL) 3190 printf("%s:\n", obj->path); 3191 for (needed = obj->needed; needed; needed = needed->next) { 3192 if (needed->obj != NULL) { 3193 if (needed->obj->traced && !list_containers) 3194 continue; 3195 needed->obj->traced = true; 3196 path = needed->obj->path; 3197 } else 3198 path = "not found"; 3199 3200 name = (char *)obj->strtab + needed->name; 3201 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3202 3203 fmt = is_lib ? fmt1 : fmt2; 3204 while ((c = *fmt++) != '\0') { 3205 switch (c) { 3206 default: 3207 putchar(c); 3208 continue; 3209 case '\\': 3210 switch (c = *fmt) { 3211 case '\0': 3212 continue; 3213 case 'n': 3214 putchar('\n'); 3215 break; 3216 case 't': 3217 putchar('\t'); 3218 break; 3219 } 3220 break; 3221 case '%': 3222 switch (c = *fmt) { 3223 case '\0': 3224 continue; 3225 case '%': 3226 default: 3227 putchar(c); 3228 break; 3229 case 'A': 3230 printf("%s", main_local); 3231 break; 3232 case 'a': 3233 printf("%s", obj_main->path); 3234 break; 3235 case 'o': 3236 printf("%s", name); 3237 break; 3238 #if 0 3239 case 'm': 3240 printf("%d", sodp->sod_major); 3241 break; 3242 case 'n': 3243 printf("%d", sodp->sod_minor); 3244 break; 3245 #endif 3246 case 'p': 3247 printf("%s", path); 3248 break; 3249 case 'x': 3250 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3251 break; 3252 } 3253 break; 3254 } 3255 ++fmt; 3256 } 3257 } 3258 } 3259 } 3260 3261 /* 3262 * Unload a dlopened object and its dependencies from memory and from 3263 * our data structures. It is assumed that the DAG rooted in the 3264 * object has already been unreferenced, and that the object has a 3265 * reference count of 0. 3266 */ 3267 static void 3268 unload_object(Obj_Entry *root) 3269 { 3270 Obj_Entry *obj; 3271 Obj_Entry **linkp; 3272 3273 assert(root->refcount == 0); 3274 3275 /* 3276 * Pass over the DAG removing unreferenced objects from 3277 * appropriate lists. 3278 */ 3279 unlink_object(root); 3280 3281 /* Unmap all objects that are no longer referenced. */ 3282 linkp = &obj_list->next; 3283 while ((obj = *linkp) != NULL) { 3284 if (obj->refcount == 0) { 3285 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3286 obj->path); 3287 dbg("unloading \"%s\"", obj->path); 3288 unload_filtees(root); 3289 munmap(obj->mapbase, obj->mapsize); 3290 linkmap_delete(obj); 3291 *linkp = obj->next; 3292 obj_count--; 3293 obj_free(obj); 3294 } else 3295 linkp = &obj->next; 3296 } 3297 obj_tail = linkp; 3298 } 3299 3300 static void 3301 unlink_object(Obj_Entry *root) 3302 { 3303 Objlist_Entry *elm; 3304 3305 if (root->refcount == 0) { 3306 /* Remove the object from the RTLD_GLOBAL list. */ 3307 objlist_remove(&list_global, root); 3308 3309 /* Remove the object from all objects' DAG lists. */ 3310 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3311 objlist_remove(&elm->obj->dldags, root); 3312 if (elm->obj != root) 3313 unlink_object(elm->obj); 3314 } 3315 } 3316 } 3317 3318 static void 3319 ref_dag(Obj_Entry *root) 3320 { 3321 Objlist_Entry *elm; 3322 3323 assert(root->dag_inited); 3324 STAILQ_FOREACH(elm, &root->dagmembers, link) 3325 elm->obj->refcount++; 3326 } 3327 3328 static void 3329 unref_dag(Obj_Entry *root) 3330 { 3331 Objlist_Entry *elm; 3332 3333 assert(root->dag_inited); 3334 STAILQ_FOREACH(elm, &root->dagmembers, link) 3335 elm->obj->refcount--; 3336 } 3337 3338 /* 3339 * Common code for MD __tls_get_addr(). 3340 */ 3341 void * 3342 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3343 { 3344 Elf_Addr* dtv = *dtvp; 3345 RtldLockState lockstate; 3346 3347 /* Check dtv generation in case new modules have arrived */ 3348 if (dtv[0] != tls_dtv_generation) { 3349 Elf_Addr* newdtv; 3350 int to_copy; 3351 3352 wlock_acquire(rtld_bind_lock, &lockstate); 3353 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3354 to_copy = dtv[1]; 3355 if (to_copy > tls_max_index) 3356 to_copy = tls_max_index; 3357 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3358 newdtv[0] = tls_dtv_generation; 3359 newdtv[1] = tls_max_index; 3360 free(dtv); 3361 lock_release(rtld_bind_lock, &lockstate); 3362 *dtvp = newdtv; 3363 } 3364 3365 /* Dynamically allocate module TLS if necessary */ 3366 if (!dtv[index + 1]) { 3367 /* Signal safe, wlock will block out signals. */ 3368 wlock_acquire(rtld_bind_lock, &lockstate); 3369 if (!dtv[index + 1]) 3370 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3371 lock_release(rtld_bind_lock, &lockstate); 3372 } 3373 return (void*) (dtv[index + 1] + offset); 3374 } 3375 3376 /* XXX not sure what variants to use for arm. */ 3377 3378 #if defined(__ia64__) || defined(__powerpc__) 3379 3380 /* 3381 * Allocate Static TLS using the Variant I method. 3382 */ 3383 void * 3384 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3385 { 3386 Obj_Entry *obj; 3387 char *tcb; 3388 Elf_Addr **tls; 3389 Elf_Addr *dtv; 3390 Elf_Addr addr; 3391 int i; 3392 3393 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3394 return (oldtcb); 3395 3396 assert(tcbsize >= TLS_TCB_SIZE); 3397 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3398 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3399 3400 if (oldtcb != NULL) { 3401 memcpy(tls, oldtcb, tls_static_space); 3402 free(oldtcb); 3403 3404 /* Adjust the DTV. */ 3405 dtv = tls[0]; 3406 for (i = 0; i < dtv[1]; i++) { 3407 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3408 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3409 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3410 } 3411 } 3412 } else { 3413 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3414 tls[0] = dtv; 3415 dtv[0] = tls_dtv_generation; 3416 dtv[1] = tls_max_index; 3417 3418 for (obj = objs; obj; obj = obj->next) { 3419 if (obj->tlsoffset > 0) { 3420 addr = (Elf_Addr)tls + obj->tlsoffset; 3421 if (obj->tlsinitsize > 0) 3422 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3423 if (obj->tlssize > obj->tlsinitsize) 3424 memset((void*) (addr + obj->tlsinitsize), 0, 3425 obj->tlssize - obj->tlsinitsize); 3426 dtv[obj->tlsindex + 1] = addr; 3427 } 3428 } 3429 } 3430 3431 return (tcb); 3432 } 3433 3434 void 3435 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3436 { 3437 Elf_Addr *dtv; 3438 Elf_Addr tlsstart, tlsend; 3439 int dtvsize, i; 3440 3441 assert(tcbsize >= TLS_TCB_SIZE); 3442 3443 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3444 tlsend = tlsstart + tls_static_space; 3445 3446 dtv = *(Elf_Addr **)tlsstart; 3447 dtvsize = dtv[1]; 3448 for (i = 0; i < dtvsize; i++) { 3449 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3450 free((void*)dtv[i+2]); 3451 } 3452 } 3453 free(dtv); 3454 free(tcb); 3455 } 3456 3457 #endif 3458 3459 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3460 defined(__arm__) || defined(__mips__) 3461 3462 /* 3463 * Allocate Static TLS using the Variant II method. 3464 */ 3465 void * 3466 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3467 { 3468 Obj_Entry *obj; 3469 size_t size; 3470 char *tls; 3471 Elf_Addr *dtv, *olddtv; 3472 Elf_Addr segbase, oldsegbase, addr; 3473 int i; 3474 3475 size = round(tls_static_space, tcbalign); 3476 3477 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3478 tls = calloc(1, size + tcbsize); 3479 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3480 3481 segbase = (Elf_Addr)(tls + size); 3482 ((Elf_Addr*)segbase)[0] = segbase; 3483 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3484 3485 dtv[0] = tls_dtv_generation; 3486 dtv[1] = tls_max_index; 3487 3488 if (oldtls) { 3489 /* 3490 * Copy the static TLS block over whole. 3491 */ 3492 oldsegbase = (Elf_Addr) oldtls; 3493 memcpy((void *)(segbase - tls_static_space), 3494 (const void *)(oldsegbase - tls_static_space), 3495 tls_static_space); 3496 3497 /* 3498 * If any dynamic TLS blocks have been created tls_get_addr(), 3499 * move them over. 3500 */ 3501 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3502 for (i = 0; i < olddtv[1]; i++) { 3503 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3504 dtv[i+2] = olddtv[i+2]; 3505 olddtv[i+2] = 0; 3506 } 3507 } 3508 3509 /* 3510 * We assume that this block was the one we created with 3511 * allocate_initial_tls(). 3512 */ 3513 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3514 } else { 3515 for (obj = objs; obj; obj = obj->next) { 3516 if (obj->tlsoffset) { 3517 addr = segbase - obj->tlsoffset; 3518 memset((void*) (addr + obj->tlsinitsize), 3519 0, obj->tlssize - obj->tlsinitsize); 3520 if (obj->tlsinit) 3521 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3522 dtv[obj->tlsindex + 1] = addr; 3523 } 3524 } 3525 } 3526 3527 return (void*) segbase; 3528 } 3529 3530 void 3531 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3532 { 3533 size_t size; 3534 Elf_Addr* dtv; 3535 int dtvsize, i; 3536 Elf_Addr tlsstart, tlsend; 3537 3538 /* 3539 * Figure out the size of the initial TLS block so that we can 3540 * find stuff which ___tls_get_addr() allocated dynamically. 3541 */ 3542 size = round(tls_static_space, tcbalign); 3543 3544 dtv = ((Elf_Addr**)tls)[1]; 3545 dtvsize = dtv[1]; 3546 tlsend = (Elf_Addr) tls; 3547 tlsstart = tlsend - size; 3548 for (i = 0; i < dtvsize; i++) { 3549 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3550 free((void*) dtv[i+2]); 3551 } 3552 } 3553 3554 free((void*) tlsstart); 3555 free((void*) dtv); 3556 } 3557 3558 #endif 3559 3560 /* 3561 * Allocate TLS block for module with given index. 3562 */ 3563 void * 3564 allocate_module_tls(int index) 3565 { 3566 Obj_Entry* obj; 3567 char* p; 3568 3569 for (obj = obj_list; obj; obj = obj->next) { 3570 if (obj->tlsindex == index) 3571 break; 3572 } 3573 if (!obj) { 3574 _rtld_error("Can't find module with TLS index %d", index); 3575 die(); 3576 } 3577 3578 p = malloc(obj->tlssize); 3579 if (p == NULL) { 3580 _rtld_error("Cannot allocate TLS block for index %d", index); 3581 die(); 3582 } 3583 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3584 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3585 3586 return p; 3587 } 3588 3589 bool 3590 allocate_tls_offset(Obj_Entry *obj) 3591 { 3592 size_t off; 3593 3594 if (obj->tls_done) 3595 return true; 3596 3597 if (obj->tlssize == 0) { 3598 obj->tls_done = true; 3599 return true; 3600 } 3601 3602 if (obj->tlsindex == 1) 3603 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3604 else 3605 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3606 obj->tlssize, obj->tlsalign); 3607 3608 /* 3609 * If we have already fixed the size of the static TLS block, we 3610 * must stay within that size. When allocating the static TLS, we 3611 * leave a small amount of space spare to be used for dynamically 3612 * loading modules which use static TLS. 3613 */ 3614 if (tls_static_space) { 3615 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3616 return false; 3617 } 3618 3619 tls_last_offset = obj->tlsoffset = off; 3620 tls_last_size = obj->tlssize; 3621 obj->tls_done = true; 3622 3623 return true; 3624 } 3625 3626 void 3627 free_tls_offset(Obj_Entry *obj) 3628 { 3629 3630 /* 3631 * If we were the last thing to allocate out of the static TLS 3632 * block, we give our space back to the 'allocator'. This is a 3633 * simplistic workaround to allow libGL.so.1 to be loaded and 3634 * unloaded multiple times. 3635 */ 3636 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3637 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3638 tls_last_offset -= obj->tlssize; 3639 tls_last_size = 0; 3640 } 3641 } 3642 3643 void * 3644 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3645 { 3646 void *ret; 3647 RtldLockState lockstate; 3648 3649 wlock_acquire(rtld_bind_lock, &lockstate); 3650 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3651 lock_release(rtld_bind_lock, &lockstate); 3652 return (ret); 3653 } 3654 3655 void 3656 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3657 { 3658 RtldLockState lockstate; 3659 3660 wlock_acquire(rtld_bind_lock, &lockstate); 3661 free_tls(tcb, tcbsize, tcbalign); 3662 lock_release(rtld_bind_lock, &lockstate); 3663 } 3664 3665 static void 3666 object_add_name(Obj_Entry *obj, const char *name) 3667 { 3668 Name_Entry *entry; 3669 size_t len; 3670 3671 len = strlen(name); 3672 entry = malloc(sizeof(Name_Entry) + len); 3673 3674 if (entry != NULL) { 3675 strcpy(entry->name, name); 3676 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3677 } 3678 } 3679 3680 static int 3681 object_match_name(const Obj_Entry *obj, const char *name) 3682 { 3683 Name_Entry *entry; 3684 3685 STAILQ_FOREACH(entry, &obj->names, link) { 3686 if (strcmp(name, entry->name) == 0) 3687 return (1); 3688 } 3689 return (0); 3690 } 3691 3692 static Obj_Entry * 3693 locate_dependency(const Obj_Entry *obj, const char *name) 3694 { 3695 const Objlist_Entry *entry; 3696 const Needed_Entry *needed; 3697 3698 STAILQ_FOREACH(entry, &list_main, link) { 3699 if (object_match_name(entry->obj, name)) 3700 return entry->obj; 3701 } 3702 3703 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3704 if (strcmp(obj->strtab + needed->name, name) == 0 || 3705 (needed->obj != NULL && object_match_name(needed->obj, name))) { 3706 /* 3707 * If there is DT_NEEDED for the name we are looking for, 3708 * we are all set. Note that object might not be found if 3709 * dependency was not loaded yet, so the function can 3710 * return NULL here. This is expected and handled 3711 * properly by the caller. 3712 */ 3713 return (needed->obj); 3714 } 3715 } 3716 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3717 obj->path, name); 3718 die(); 3719 } 3720 3721 static int 3722 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3723 const Elf_Vernaux *vna) 3724 { 3725 const Elf_Verdef *vd; 3726 const char *vername; 3727 3728 vername = refobj->strtab + vna->vna_name; 3729 vd = depobj->verdef; 3730 if (vd == NULL) { 3731 _rtld_error("%s: version %s required by %s not defined", 3732 depobj->path, vername, refobj->path); 3733 return (-1); 3734 } 3735 for (;;) { 3736 if (vd->vd_version != VER_DEF_CURRENT) { 3737 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3738 depobj->path, vd->vd_version); 3739 return (-1); 3740 } 3741 if (vna->vna_hash == vd->vd_hash) { 3742 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3743 ((char *)vd + vd->vd_aux); 3744 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3745 return (0); 3746 } 3747 if (vd->vd_next == 0) 3748 break; 3749 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3750 } 3751 if (vna->vna_flags & VER_FLG_WEAK) 3752 return (0); 3753 _rtld_error("%s: version %s required by %s not found", 3754 depobj->path, vername, refobj->path); 3755 return (-1); 3756 } 3757 3758 static int 3759 rtld_verify_object_versions(Obj_Entry *obj) 3760 { 3761 const Elf_Verneed *vn; 3762 const Elf_Verdef *vd; 3763 const Elf_Verdaux *vda; 3764 const Elf_Vernaux *vna; 3765 const Obj_Entry *depobj; 3766 int maxvernum, vernum; 3767 3768 maxvernum = 0; 3769 /* 3770 * Walk over defined and required version records and figure out 3771 * max index used by any of them. Do very basic sanity checking 3772 * while there. 3773 */ 3774 vn = obj->verneed; 3775 while (vn != NULL) { 3776 if (vn->vn_version != VER_NEED_CURRENT) { 3777 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3778 obj->path, vn->vn_version); 3779 return (-1); 3780 } 3781 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3782 for (;;) { 3783 vernum = VER_NEED_IDX(vna->vna_other); 3784 if (vernum > maxvernum) 3785 maxvernum = vernum; 3786 if (vna->vna_next == 0) 3787 break; 3788 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3789 } 3790 if (vn->vn_next == 0) 3791 break; 3792 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3793 } 3794 3795 vd = obj->verdef; 3796 while (vd != NULL) { 3797 if (vd->vd_version != VER_DEF_CURRENT) { 3798 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3799 obj->path, vd->vd_version); 3800 return (-1); 3801 } 3802 vernum = VER_DEF_IDX(vd->vd_ndx); 3803 if (vernum > maxvernum) 3804 maxvernum = vernum; 3805 if (vd->vd_next == 0) 3806 break; 3807 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3808 } 3809 3810 if (maxvernum == 0) 3811 return (0); 3812 3813 /* 3814 * Store version information in array indexable by version index. 3815 * Verify that object version requirements are satisfied along the 3816 * way. 3817 */ 3818 obj->vernum = maxvernum + 1; 3819 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3820 3821 vd = obj->verdef; 3822 while (vd != NULL) { 3823 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3824 vernum = VER_DEF_IDX(vd->vd_ndx); 3825 assert(vernum <= maxvernum); 3826 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3827 obj->vertab[vernum].hash = vd->vd_hash; 3828 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3829 obj->vertab[vernum].file = NULL; 3830 obj->vertab[vernum].flags = 0; 3831 } 3832 if (vd->vd_next == 0) 3833 break; 3834 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3835 } 3836 3837 vn = obj->verneed; 3838 while (vn != NULL) { 3839 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3840 if (depobj == NULL) 3841 return (-1); 3842 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3843 for (;;) { 3844 if (check_object_provided_version(obj, depobj, vna)) 3845 return (-1); 3846 vernum = VER_NEED_IDX(vna->vna_other); 3847 assert(vernum <= maxvernum); 3848 obj->vertab[vernum].hash = vna->vna_hash; 3849 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3850 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3851 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3852 VER_INFO_HIDDEN : 0; 3853 if (vna->vna_next == 0) 3854 break; 3855 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3856 } 3857 if (vn->vn_next == 0) 3858 break; 3859 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3860 } 3861 return 0; 3862 } 3863 3864 static int 3865 rtld_verify_versions(const Objlist *objlist) 3866 { 3867 Objlist_Entry *entry; 3868 int rc; 3869 3870 rc = 0; 3871 STAILQ_FOREACH(entry, objlist, link) { 3872 /* 3873 * Skip dummy objects or objects that have their version requirements 3874 * already checked. 3875 */ 3876 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3877 continue; 3878 if (rtld_verify_object_versions(entry->obj) == -1) { 3879 rc = -1; 3880 if (ld_tracing == NULL) 3881 break; 3882 } 3883 } 3884 if (rc == 0 || ld_tracing != NULL) 3885 rc = rtld_verify_object_versions(&obj_rtld); 3886 return rc; 3887 } 3888 3889 const Ver_Entry * 3890 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3891 { 3892 Elf_Versym vernum; 3893 3894 if (obj->vertab) { 3895 vernum = VER_NDX(obj->versyms[symnum]); 3896 if (vernum >= obj->vernum) { 3897 _rtld_error("%s: symbol %s has wrong verneed value %d", 3898 obj->path, obj->strtab + symnum, vernum); 3899 } else if (obj->vertab[vernum].hash != 0) { 3900 return &obj->vertab[vernum]; 3901 } 3902 } 3903 return NULL; 3904 } 3905 3906 int 3907 _rtld_get_stack_prot(void) 3908 { 3909 3910 return (stack_prot); 3911 } 3912 3913 static void 3914 map_stacks_exec(RtldLockState *lockstate) 3915 { 3916 void (*thr_map_stacks_exec)(void); 3917 3918 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 3919 return; 3920 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 3921 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 3922 if (thr_map_stacks_exec != NULL) { 3923 stack_prot |= PROT_EXEC; 3924 thr_map_stacks_exec(); 3925 } 3926 } 3927 3928 void 3929 symlook_init(SymLook *dst, const char *name) 3930 { 3931 3932 bzero(dst, sizeof(*dst)); 3933 dst->name = name; 3934 dst->hash = elf_hash(name); 3935 } 3936 3937 static void 3938 symlook_init_from_req(SymLook *dst, const SymLook *src) 3939 { 3940 3941 dst->name = src->name; 3942 dst->hash = src->hash; 3943 dst->ventry = src->ventry; 3944 dst->flags = src->flags; 3945 dst->defobj_out = NULL; 3946 dst->sym_out = NULL; 3947 dst->lockstate = src->lockstate; 3948 } 3949 3950 /* 3951 * Overrides for libc_pic-provided functions. 3952 */ 3953 3954 int 3955 __getosreldate(void) 3956 { 3957 size_t len; 3958 int oid[2]; 3959 int error, osrel; 3960 3961 if (osreldate != 0) 3962 return (osreldate); 3963 3964 oid[0] = CTL_KERN; 3965 oid[1] = KERN_OSRELDATE; 3966 osrel = 0; 3967 len = sizeof(osrel); 3968 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 3969 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 3970 osreldate = osrel; 3971 return (osreldate); 3972 } 3973 3974 /* 3975 * No unresolved symbols for rtld. 3976 */ 3977 void 3978 __pthread_cxa_finalize(struct dl_phdr_info *a) 3979 { 3980 } 3981