1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 /* 30 * Dynamic linker for ELF. 31 * 32 * John Polstra <jdp@polstra.com>. 33 */ 34 35 #ifndef __GNUC__ 36 #error "GCC is needed to compile this file" 37 #endif 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/sysctl.h> 44 #include <sys/uio.h> 45 #include <sys/utsname.h> 46 #include <sys/ktrace.h> 47 48 #include <dlfcn.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <stdarg.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 #include "debug.h" 59 #include "rtld.h" 60 #include "libmap.h" 61 #include "rtld_tls.h" 62 63 #ifndef COMPAT_32BIT 64 #define PATH_RTLD "/libexec/ld-elf.so.1" 65 #else 66 #define PATH_RTLD "/libexec/ld-elf32.so.1" 67 #endif 68 69 /* Types. */ 70 typedef void (*func_ptr_type)(); 71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73 /* 74 * Function declarations. 75 */ 76 static const char *basename(const char *); 77 static void die(void) __dead2; 78 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 79 const Elf_Dyn **); 80 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 81 static void digest_dynamic(Obj_Entry *, int); 82 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 83 static Obj_Entry *dlcheck(void *); 84 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj, 85 int lo_flags, int mode); 86 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 87 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 88 static bool donelist_check(DoneList *, const Obj_Entry *); 89 static void errmsg_restore(char *); 90 static char *errmsg_save(void); 91 static void *fill_search_info(const char *, size_t, void *); 92 static char *find_library(const char *, const Obj_Entry *); 93 static const char *gethints(void); 94 static void init_dag(Obj_Entry *); 95 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 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 | PROT_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 (setjmp(lockstate.env) != 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 DoneList donelist; 1334 1335 if (root->dag_inited) 1336 return; 1337 donelist_init(&donelist); 1338 init_dag1(root, root, &donelist); 1339 root->dag_inited = true; 1340 } 1341 1342 static void 1343 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1344 { 1345 const Needed_Entry *needed; 1346 1347 if (donelist_check(dlp, obj)) 1348 return; 1349 1350 objlist_push_tail(&obj->dldags, root); 1351 objlist_push_tail(&root->dagmembers, obj); 1352 for (needed = obj->needed; needed != NULL; needed = needed->next) 1353 if (needed->obj != NULL) 1354 init_dag1(root, needed->obj, dlp); 1355 } 1356 1357 /* 1358 * Initialize the dynamic linker. The argument is the address at which 1359 * the dynamic linker has been mapped into memory. The primary task of 1360 * this function is to relocate the dynamic linker. 1361 */ 1362 static void 1363 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1364 { 1365 Obj_Entry objtmp; /* Temporary rtld object */ 1366 const Elf_Dyn *dyn_rpath; 1367 const Elf_Dyn *dyn_soname; 1368 1369 /* 1370 * Conjure up an Obj_Entry structure for the dynamic linker. 1371 * 1372 * The "path" member can't be initialized yet because string constants 1373 * cannot yet be accessed. Below we will set it correctly. 1374 */ 1375 memset(&objtmp, 0, sizeof(objtmp)); 1376 objtmp.path = NULL; 1377 objtmp.rtld = true; 1378 objtmp.mapbase = mapbase; 1379 #ifdef PIC 1380 objtmp.relocbase = mapbase; 1381 #endif 1382 if (RTLD_IS_DYNAMIC()) { 1383 objtmp.dynamic = rtld_dynamic(&objtmp); 1384 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1385 assert(objtmp.needed == NULL); 1386 #if !defined(__mips__) 1387 /* MIPS and SH{3,5} have a bogus DT_TEXTREL. */ 1388 assert(!objtmp.textrel); 1389 #endif 1390 1391 /* 1392 * Temporarily put the dynamic linker entry into the object list, so 1393 * that symbols can be found. 1394 */ 1395 1396 relocate_objects(&objtmp, true, &objtmp, NULL); 1397 } 1398 1399 /* Initialize the object list. */ 1400 obj_tail = &obj_list; 1401 1402 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1403 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1404 1405 if (aux_info[AT_PAGESZ] != NULL) 1406 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1407 if (aux_info[AT_OSRELDATE] != NULL) 1408 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1409 1410 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1411 1412 /* Replace the path with a dynamically allocated copy. */ 1413 obj_rtld.path = xstrdup(PATH_RTLD); 1414 1415 r_debug.r_brk = r_debug_state; 1416 r_debug.r_state = RT_CONSISTENT; 1417 } 1418 1419 /* 1420 * Add the init functions from a needed object list (and its recursive 1421 * needed objects) to "list". This is not used directly; it is a helper 1422 * function for initlist_add_objects(). The write lock must be held 1423 * when this function is called. 1424 */ 1425 static void 1426 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1427 { 1428 /* Recursively process the successor needed objects. */ 1429 if (needed->next != NULL) 1430 initlist_add_neededs(needed->next, list); 1431 1432 /* Process the current needed object. */ 1433 if (needed->obj != NULL) 1434 initlist_add_objects(needed->obj, &needed->obj->next, list); 1435 } 1436 1437 /* 1438 * Scan all of the DAGs rooted in the range of objects from "obj" to 1439 * "tail" and add their init functions to "list". This recurses over 1440 * the DAGs and ensure the proper init ordering such that each object's 1441 * needed libraries are initialized before the object itself. At the 1442 * same time, this function adds the objects to the global finalization 1443 * list "list_fini" in the opposite order. The write lock must be 1444 * held when this function is called. 1445 */ 1446 static void 1447 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1448 { 1449 if (obj->init_scanned || obj->init_done) 1450 return; 1451 obj->init_scanned = true; 1452 1453 /* Recursively process the successor objects. */ 1454 if (&obj->next != tail) 1455 initlist_add_objects(obj->next, tail, list); 1456 1457 /* Recursively process the needed objects. */ 1458 if (obj->needed != NULL) 1459 initlist_add_neededs(obj->needed, list); 1460 1461 /* Add the object to the init list. */ 1462 if (obj->init != (Elf_Addr)NULL) 1463 objlist_push_tail(list, obj); 1464 1465 /* Add the object to the global fini list in the reverse order. */ 1466 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1467 objlist_push_head(&list_fini, obj); 1468 obj->on_fini_list = true; 1469 } 1470 } 1471 1472 #ifndef FPTR_TARGET 1473 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1474 #endif 1475 1476 static void 1477 free_needed_filtees(Needed_Entry *n) 1478 { 1479 Needed_Entry *needed, *needed1; 1480 1481 for (needed = n; needed != NULL; needed = needed->next) { 1482 if (needed->obj != NULL) { 1483 dlclose(needed->obj); 1484 needed->obj = NULL; 1485 } 1486 } 1487 for (needed = n; needed != NULL; needed = needed1) { 1488 needed1 = needed->next; 1489 free(needed); 1490 } 1491 } 1492 1493 static void 1494 unload_filtees(Obj_Entry *obj) 1495 { 1496 1497 free_needed_filtees(obj->needed_filtees); 1498 obj->needed_filtees = NULL; 1499 free_needed_filtees(obj->needed_aux_filtees); 1500 obj->needed_aux_filtees = NULL; 1501 obj->filtees_loaded = false; 1502 } 1503 1504 static void 1505 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags) 1506 { 1507 1508 for (; needed != NULL; needed = needed->next) { 1509 needed->obj = dlopen_object(obj->strtab + needed->name, obj, 1510 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1511 RTLD_LOCAL); 1512 } 1513 } 1514 1515 static void 1516 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1517 { 1518 1519 lock_restart_for_upgrade(lockstate); 1520 if (!obj->filtees_loaded) { 1521 load_filtee1(obj, obj->needed_filtees, flags); 1522 load_filtee1(obj, obj->needed_aux_filtees, flags); 1523 obj->filtees_loaded = true; 1524 } 1525 } 1526 1527 static int 1528 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1529 { 1530 Obj_Entry *obj1; 1531 1532 for (; needed != NULL; needed = needed->next) { 1533 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1534 flags & ~RTLD_LO_NOLOAD); 1535 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1536 return (-1); 1537 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1538 dbg("obj %s nodelete", obj1->path); 1539 init_dag(obj1); 1540 ref_dag(obj1); 1541 obj1->ref_nodel = true; 1542 } 1543 } 1544 return (0); 1545 } 1546 1547 /* 1548 * Given a shared object, traverse its list of needed objects, and load 1549 * each of them. Returns 0 on success. Generates an error message and 1550 * returns -1 on failure. 1551 */ 1552 static int 1553 load_needed_objects(Obj_Entry *first, int flags) 1554 { 1555 Obj_Entry *obj; 1556 1557 for (obj = first; obj != NULL; obj = obj->next) { 1558 if (process_needed(obj, obj->needed, flags) == -1) 1559 return (-1); 1560 } 1561 return (0); 1562 } 1563 1564 static int 1565 load_preload_objects(void) 1566 { 1567 char *p = ld_preload; 1568 static const char delim[] = " \t:;"; 1569 1570 if (p == NULL) 1571 return 0; 1572 1573 p += strspn(p, delim); 1574 while (*p != '\0') { 1575 size_t len = strcspn(p, delim); 1576 char savech; 1577 1578 savech = p[len]; 1579 p[len] = '\0'; 1580 if (load_object(p, NULL, 0) == NULL) 1581 return -1; /* XXX - cleanup */ 1582 p[len] = savech; 1583 p += len; 1584 p += strspn(p, delim); 1585 } 1586 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1587 return 0; 1588 } 1589 1590 /* 1591 * Load a shared object into memory, if it is not already loaded. 1592 * 1593 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1594 * on failure. 1595 */ 1596 static Obj_Entry * 1597 load_object(const char *name, const Obj_Entry *refobj, int flags) 1598 { 1599 Obj_Entry *obj; 1600 int fd = -1; 1601 struct stat sb; 1602 char *path; 1603 1604 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1605 if (object_match_name(obj, name)) 1606 return obj; 1607 1608 path = find_library(name, refobj); 1609 if (path == NULL) 1610 return NULL; 1611 1612 /* 1613 * If we didn't find a match by pathname, open the file and check 1614 * again by device and inode. This avoids false mismatches caused 1615 * by multiple links or ".." in pathnames. 1616 * 1617 * To avoid a race, we open the file and use fstat() rather than 1618 * using stat(). 1619 */ 1620 if ((fd = open(path, O_RDONLY)) == -1) { 1621 _rtld_error("Cannot open \"%s\"", path); 1622 free(path); 1623 return NULL; 1624 } 1625 if (fstat(fd, &sb) == -1) { 1626 _rtld_error("Cannot fstat \"%s\"", path); 1627 close(fd); 1628 free(path); 1629 return NULL; 1630 } 1631 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1632 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) { 1633 close(fd); 1634 break; 1635 } 1636 } 1637 if (obj != NULL) { 1638 object_add_name(obj, name); 1639 free(path); 1640 close(fd); 1641 return obj; 1642 } 1643 if (flags & RTLD_LO_NOLOAD) { 1644 free(path); 1645 return (NULL); 1646 } 1647 1648 /* First use of this object, so we must map it in */ 1649 obj = do_load_object(fd, name, path, &sb, flags); 1650 if (obj == NULL) 1651 free(path); 1652 close(fd); 1653 1654 return obj; 1655 } 1656 1657 static Obj_Entry * 1658 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1659 int flags) 1660 { 1661 Obj_Entry *obj; 1662 struct statfs fs; 1663 1664 /* 1665 * but first, make sure that environment variables haven't been 1666 * used to circumvent the noexec flag on a filesystem. 1667 */ 1668 if (dangerous_ld_env) { 1669 if (fstatfs(fd, &fs) != 0) { 1670 _rtld_error("Cannot fstatfs \"%s\"", path); 1671 return NULL; 1672 } 1673 if (fs.f_flags & MNT_NOEXEC) { 1674 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1675 return NULL; 1676 } 1677 } 1678 dbg("loading \"%s\"", path); 1679 obj = map_object(fd, path, sbp); 1680 if (obj == NULL) 1681 return NULL; 1682 1683 object_add_name(obj, name); 1684 obj->path = path; 1685 digest_dynamic(obj, 0); 1686 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1687 RTLD_LO_DLOPEN) { 1688 dbg("refusing to load non-loadable \"%s\"", obj->path); 1689 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1690 munmap(obj->mapbase, obj->mapsize); 1691 obj_free(obj); 1692 return (NULL); 1693 } 1694 1695 *obj_tail = obj; 1696 obj_tail = &obj->next; 1697 obj_count++; 1698 obj_loads++; 1699 linkmap_add(obj); /* for GDB & dlinfo() */ 1700 max_stack_flags |= obj->stack_flags; 1701 1702 dbg(" %p .. %p: %s", obj->mapbase, 1703 obj->mapbase + obj->mapsize - 1, obj->path); 1704 if (obj->textrel) 1705 dbg(" WARNING: %s has impure text", obj->path); 1706 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1707 obj->path); 1708 1709 return obj; 1710 } 1711 1712 static Obj_Entry * 1713 obj_from_addr(const void *addr) 1714 { 1715 Obj_Entry *obj; 1716 1717 for (obj = obj_list; obj != NULL; obj = obj->next) { 1718 if (addr < (void *) obj->mapbase) 1719 continue; 1720 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1721 return obj; 1722 } 1723 return NULL; 1724 } 1725 1726 /* 1727 * Call the finalization functions for each of the objects in "list" 1728 * belonging to the DAG of "root" and referenced once. If NULL "root" 1729 * is specified, every finalization function will be called regardless 1730 * of the reference count and the list elements won't be freed. All of 1731 * the objects are expected to have non-NULL fini functions. 1732 */ 1733 static void 1734 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1735 { 1736 Objlist_Entry *elm; 1737 char *saved_msg; 1738 1739 assert(root == NULL || root->refcount == 1); 1740 1741 /* 1742 * Preserve the current error message since a fini function might 1743 * call into the dynamic linker and overwrite it. 1744 */ 1745 saved_msg = errmsg_save(); 1746 do { 1747 STAILQ_FOREACH(elm, list, link) { 1748 if (root != NULL && (elm->obj->refcount != 1 || 1749 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1750 continue; 1751 dbg("calling fini function for %s at %p", elm->obj->path, 1752 (void *)elm->obj->fini); 1753 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1754 elm->obj->path); 1755 /* Remove object from fini list to prevent recursive invocation. */ 1756 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1757 /* 1758 * XXX: If a dlopen() call references an object while the 1759 * fini function is in progress, we might end up trying to 1760 * unload the referenced object in dlclose() or the object 1761 * won't be unloaded although its fini function has been 1762 * called. 1763 */ 1764 lock_release(rtld_bind_lock, lockstate); 1765 call_initfini_pointer(elm->obj, elm->obj->fini); 1766 wlock_acquire(rtld_bind_lock, lockstate); 1767 /* No need to free anything if process is going down. */ 1768 if (root != NULL) 1769 free(elm); 1770 /* 1771 * We must restart the list traversal after every fini call 1772 * because a dlclose() call from the fini function or from 1773 * another thread might have modified the reference counts. 1774 */ 1775 break; 1776 } 1777 } while (elm != NULL); 1778 errmsg_restore(saved_msg); 1779 } 1780 1781 /* 1782 * Call the initialization functions for each of the objects in 1783 * "list". All of the objects are expected to have non-NULL init 1784 * functions. 1785 */ 1786 static void 1787 objlist_call_init(Objlist *list, RtldLockState *lockstate) 1788 { 1789 Objlist_Entry *elm; 1790 Obj_Entry *obj; 1791 char *saved_msg; 1792 1793 /* 1794 * Clean init_scanned flag so that objects can be rechecked and 1795 * possibly initialized earlier if any of vectors called below 1796 * cause the change by using dlopen. 1797 */ 1798 for (obj = obj_list; obj != NULL; obj = obj->next) 1799 obj->init_scanned = false; 1800 1801 /* 1802 * Preserve the current error message since an init function might 1803 * call into the dynamic linker and overwrite it. 1804 */ 1805 saved_msg = errmsg_save(); 1806 STAILQ_FOREACH(elm, list, link) { 1807 if (elm->obj->init_done) /* Initialized early. */ 1808 continue; 1809 dbg("calling init function for %s at %p", elm->obj->path, 1810 (void *)elm->obj->init); 1811 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1812 elm->obj->path); 1813 /* 1814 * Race: other thread might try to use this object before current 1815 * one completes the initilization. Not much can be done here 1816 * without better locking. 1817 */ 1818 elm->obj->init_done = true; 1819 lock_release(rtld_bind_lock, lockstate); 1820 call_initfini_pointer(elm->obj, elm->obj->init); 1821 wlock_acquire(rtld_bind_lock, lockstate); 1822 } 1823 errmsg_restore(saved_msg); 1824 } 1825 1826 static void 1827 objlist_clear(Objlist *list) 1828 { 1829 Objlist_Entry *elm; 1830 1831 while (!STAILQ_EMPTY(list)) { 1832 elm = STAILQ_FIRST(list); 1833 STAILQ_REMOVE_HEAD(list, link); 1834 free(elm); 1835 } 1836 } 1837 1838 static Objlist_Entry * 1839 objlist_find(Objlist *list, const Obj_Entry *obj) 1840 { 1841 Objlist_Entry *elm; 1842 1843 STAILQ_FOREACH(elm, list, link) 1844 if (elm->obj == obj) 1845 return elm; 1846 return NULL; 1847 } 1848 1849 static void 1850 objlist_init(Objlist *list) 1851 { 1852 STAILQ_INIT(list); 1853 } 1854 1855 static void 1856 objlist_push_head(Objlist *list, Obj_Entry *obj) 1857 { 1858 Objlist_Entry *elm; 1859 1860 elm = NEW(Objlist_Entry); 1861 elm->obj = obj; 1862 STAILQ_INSERT_HEAD(list, elm, link); 1863 } 1864 1865 static void 1866 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1867 { 1868 Objlist_Entry *elm; 1869 1870 elm = NEW(Objlist_Entry); 1871 elm->obj = obj; 1872 STAILQ_INSERT_TAIL(list, elm, link); 1873 } 1874 1875 static void 1876 objlist_remove(Objlist *list, Obj_Entry *obj) 1877 { 1878 Objlist_Entry *elm; 1879 1880 if ((elm = objlist_find(list, obj)) != NULL) { 1881 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1882 free(elm); 1883 } 1884 } 1885 1886 /* 1887 * Relocate newly-loaded shared objects. The argument is a pointer to 1888 * the Obj_Entry for the first such object. All objects from the first 1889 * to the end of the list of objects are relocated. Returns 0 on success, 1890 * or -1 on failure. 1891 */ 1892 static int 1893 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 1894 RtldLockState *lockstate) 1895 { 1896 Obj_Entry *obj; 1897 1898 for (obj = first; obj != NULL; obj = obj->next) { 1899 if (obj != rtldobj) 1900 dbg("relocating \"%s\"", obj->path); 1901 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1902 obj->symtab == NULL || obj->strtab == NULL) { 1903 _rtld_error("%s: Shared object has no run-time symbol table", 1904 obj->path); 1905 return -1; 1906 } 1907 1908 if (obj->textrel) { 1909 /* There are relocations to the write-protected text segment. */ 1910 if (mprotect(obj->mapbase, obj->textsize, 1911 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1912 _rtld_error("%s: Cannot write-enable text segment: %s", 1913 obj->path, strerror(errno)); 1914 return -1; 1915 } 1916 } 1917 1918 /* Process the non-PLT relocations. */ 1919 if (reloc_non_plt(obj, rtldobj, lockstate)) 1920 return -1; 1921 1922 if (obj->textrel) { /* Re-protected the text segment. */ 1923 if (mprotect(obj->mapbase, obj->textsize, 1924 PROT_READ|PROT_EXEC) == -1) { 1925 _rtld_error("%s: Cannot write-protect text segment: %s", 1926 obj->path, strerror(errno)); 1927 return -1; 1928 } 1929 } 1930 1931 /* Process the PLT relocations. */ 1932 if (reloc_plt(obj) == -1) 1933 return -1; 1934 /* Relocate the jump slots if we are doing immediate binding. */ 1935 if (obj->bind_now || bind_now) 1936 if (reloc_jmpslots(obj, lockstate) == -1) 1937 return -1; 1938 1939 1940 /* 1941 * Set up the magic number and version in the Obj_Entry. These 1942 * were checked in the crt1.o from the original ElfKit, so we 1943 * set them for backward compatibility. 1944 */ 1945 obj->magic = RTLD_MAGIC; 1946 obj->version = RTLD_VERSION; 1947 1948 /* Set the special PLT or GOT entries. */ 1949 init_pltgot(obj); 1950 } 1951 1952 return 0; 1953 } 1954 1955 /* 1956 * Cleanup procedure. It will be called (by the atexit mechanism) just 1957 * before the process exits. 1958 */ 1959 static void 1960 rtld_exit(void) 1961 { 1962 RtldLockState lockstate; 1963 1964 wlock_acquire(rtld_bind_lock, &lockstate); 1965 dbg("rtld_exit()"); 1966 objlist_call_fini(&list_fini, NULL, &lockstate); 1967 /* No need to remove the items from the list, since we are exiting. */ 1968 if (!libmap_disable) 1969 lm_fini(); 1970 lock_release(rtld_bind_lock, &lockstate); 1971 } 1972 1973 static void * 1974 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1975 { 1976 #ifdef COMPAT_32BIT 1977 const char *trans; 1978 #endif 1979 if (path == NULL) 1980 return (NULL); 1981 1982 path += strspn(path, ":;"); 1983 while (*path != '\0') { 1984 size_t len; 1985 char *res; 1986 1987 len = strcspn(path, ":;"); 1988 #ifdef COMPAT_32BIT 1989 trans = lm_findn(NULL, path, len); 1990 if (trans) 1991 res = callback(trans, strlen(trans), arg); 1992 else 1993 #endif 1994 res = callback(path, len, arg); 1995 1996 if (res != NULL) 1997 return (res); 1998 1999 path += len; 2000 path += strspn(path, ":;"); 2001 } 2002 2003 return (NULL); 2004 } 2005 2006 struct try_library_args { 2007 const char *name; 2008 size_t namelen; 2009 char *buffer; 2010 size_t buflen; 2011 }; 2012 2013 static void * 2014 try_library_path(const char *dir, size_t dirlen, void *param) 2015 { 2016 struct try_library_args *arg; 2017 2018 arg = param; 2019 if (*dir == '/' || trust) { 2020 char *pathname; 2021 2022 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2023 return (NULL); 2024 2025 pathname = arg->buffer; 2026 strncpy(pathname, dir, dirlen); 2027 pathname[dirlen] = '/'; 2028 strcpy(pathname + dirlen + 1, arg->name); 2029 2030 dbg(" Trying \"%s\"", pathname); 2031 if (access(pathname, F_OK) == 0) { /* We found it */ 2032 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2033 strcpy(pathname, arg->buffer); 2034 return (pathname); 2035 } 2036 } 2037 return (NULL); 2038 } 2039 2040 static char * 2041 search_library_path(const char *name, const char *path) 2042 { 2043 char *p; 2044 struct try_library_args arg; 2045 2046 if (path == NULL) 2047 return NULL; 2048 2049 arg.name = name; 2050 arg.namelen = strlen(name); 2051 arg.buffer = xmalloc(PATH_MAX); 2052 arg.buflen = PATH_MAX; 2053 2054 p = path_enumerate(path, try_library_path, &arg); 2055 2056 free(arg.buffer); 2057 2058 return (p); 2059 } 2060 2061 int 2062 dlclose(void *handle) 2063 { 2064 Obj_Entry *root; 2065 RtldLockState lockstate; 2066 2067 wlock_acquire(rtld_bind_lock, &lockstate); 2068 root = dlcheck(handle); 2069 if (root == NULL) { 2070 lock_release(rtld_bind_lock, &lockstate); 2071 return -1; 2072 } 2073 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2074 root->path); 2075 2076 /* Unreference the object and its dependencies. */ 2077 root->dl_refcount--; 2078 2079 if (root->refcount == 1) { 2080 /* 2081 * The object will be no longer referenced, so we must unload it. 2082 * First, call the fini functions. 2083 */ 2084 objlist_call_fini(&list_fini, root, &lockstate); 2085 2086 unref_dag(root); 2087 2088 /* Finish cleaning up the newly-unreferenced objects. */ 2089 GDB_STATE(RT_DELETE,&root->linkmap); 2090 unload_object(root); 2091 GDB_STATE(RT_CONSISTENT,NULL); 2092 } else 2093 unref_dag(root); 2094 2095 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2096 lock_release(rtld_bind_lock, &lockstate); 2097 return 0; 2098 } 2099 2100 char * 2101 dlerror(void) 2102 { 2103 char *msg = error_message; 2104 error_message = NULL; 2105 return msg; 2106 } 2107 2108 /* 2109 * This function is deprecated and has no effect. 2110 */ 2111 void 2112 dllockinit(void *context, 2113 void *(*lock_create)(void *context), 2114 void (*rlock_acquire)(void *lock), 2115 void (*wlock_acquire)(void *lock), 2116 void (*lock_release)(void *lock), 2117 void (*lock_destroy)(void *lock), 2118 void (*context_destroy)(void *context)) 2119 { 2120 static void *cur_context; 2121 static void (*cur_context_destroy)(void *); 2122 2123 /* Just destroy the context from the previous call, if necessary. */ 2124 if (cur_context_destroy != NULL) 2125 cur_context_destroy(cur_context); 2126 cur_context = context; 2127 cur_context_destroy = context_destroy; 2128 } 2129 2130 void * 2131 dlopen(const char *name, int mode) 2132 { 2133 RtldLockState lockstate; 2134 int lo_flags; 2135 2136 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2137 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2138 if (ld_tracing != NULL) { 2139 rlock_acquire(rtld_bind_lock, &lockstate); 2140 if (setjmp(lockstate.env) != 0) 2141 lock_upgrade(rtld_bind_lock, &lockstate); 2142 environ = (char **)*get_program_var_addr("environ", &lockstate); 2143 lock_release(rtld_bind_lock, &lockstate); 2144 } 2145 lo_flags = RTLD_LO_DLOPEN; 2146 if (mode & RTLD_NODELETE) 2147 lo_flags |= RTLD_LO_NODELETE; 2148 if (mode & RTLD_NOLOAD) 2149 lo_flags |= RTLD_LO_NOLOAD; 2150 if (ld_tracing != NULL) 2151 lo_flags |= RTLD_LO_TRACE; 2152 2153 return (dlopen_object(name, obj_main, lo_flags, 2154 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2155 } 2156 2157 static Obj_Entry * 2158 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode) 2159 { 2160 Obj_Entry **old_obj_tail; 2161 Obj_Entry *obj; 2162 Objlist initlist; 2163 RtldLockState lockstate; 2164 int result; 2165 2166 objlist_init(&initlist); 2167 2168 wlock_acquire(rtld_bind_lock, &lockstate); 2169 GDB_STATE(RT_ADD,NULL); 2170 2171 old_obj_tail = obj_tail; 2172 obj = NULL; 2173 if (name == NULL) { 2174 obj = obj_main; 2175 obj->refcount++; 2176 } else { 2177 obj = load_object(name, refobj, lo_flags); 2178 } 2179 2180 if (obj) { 2181 obj->dl_refcount++; 2182 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2183 objlist_push_tail(&list_global, obj); 2184 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2185 assert(*old_obj_tail == obj); 2186 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN); 2187 init_dag(obj); 2188 ref_dag(obj); 2189 if (result != -1) 2190 result = rtld_verify_versions(&obj->dagmembers); 2191 if (result != -1 && ld_tracing) 2192 goto trace; 2193 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK) 2194 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) { 2195 obj->dl_refcount--; 2196 unref_dag(obj); 2197 if (obj->refcount == 0) 2198 unload_object(obj); 2199 obj = NULL; 2200 } else { 2201 /* Make list of init functions to call. */ 2202 initlist_add_objects(obj, &obj->next, &initlist); 2203 } 2204 } else { 2205 2206 /* 2207 * Bump the reference counts for objects on this DAG. If 2208 * this is the first dlopen() call for the object that was 2209 * already loaded as a dependency, initialize the dag 2210 * starting at it. 2211 */ 2212 init_dag(obj); 2213 ref_dag(obj); 2214 2215 if ((lo_flags & RTLD_LO_TRACE) != 0) 2216 goto trace; 2217 } 2218 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2219 obj->z_nodelete) && !obj->ref_nodel) { 2220 dbg("obj %s nodelete", obj->path); 2221 ref_dag(obj); 2222 obj->z_nodelete = obj->ref_nodel = true; 2223 } 2224 } 2225 2226 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2227 name); 2228 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2229 2230 map_stacks_exec(&lockstate); 2231 2232 /* Call the init functions. */ 2233 objlist_call_init(&initlist, &lockstate); 2234 objlist_clear(&initlist); 2235 lock_release(rtld_bind_lock, &lockstate); 2236 return obj; 2237 trace: 2238 trace_loaded_objects(obj); 2239 lock_release(rtld_bind_lock, &lockstate); 2240 exit(0); 2241 } 2242 2243 static void * 2244 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2245 int flags) 2246 { 2247 DoneList donelist; 2248 const Obj_Entry *obj, *defobj; 2249 const Elf_Sym *def; 2250 SymLook req; 2251 RtldLockState lockstate; 2252 int res; 2253 2254 def = NULL; 2255 defobj = NULL; 2256 symlook_init(&req, name); 2257 req.ventry = ve; 2258 req.flags = flags | SYMLOOK_IN_PLT; 2259 req.lockstate = &lockstate; 2260 2261 rlock_acquire(rtld_bind_lock, &lockstate); 2262 if (setjmp(lockstate.env) != 0) 2263 lock_upgrade(rtld_bind_lock, &lockstate); 2264 if (handle == NULL || handle == RTLD_NEXT || 2265 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2266 2267 if ((obj = obj_from_addr(retaddr)) == NULL) { 2268 _rtld_error("Cannot determine caller's shared object"); 2269 lock_release(rtld_bind_lock, &lockstate); 2270 return NULL; 2271 } 2272 if (handle == NULL) { /* Just the caller's shared object. */ 2273 res = symlook_obj(&req, obj); 2274 if (res == 0) { 2275 def = req.sym_out; 2276 defobj = req.defobj_out; 2277 } 2278 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2279 handle == RTLD_SELF) { /* ... caller included */ 2280 if (handle == RTLD_NEXT) 2281 obj = obj->next; 2282 for (; obj != NULL; obj = obj->next) { 2283 res = symlook_obj(&req, obj); 2284 if (res == 0) { 2285 if (def == NULL || 2286 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2287 def = req.sym_out; 2288 defobj = req.defobj_out; 2289 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2290 break; 2291 } 2292 } 2293 } 2294 /* 2295 * Search the dynamic linker itself, and possibly resolve the 2296 * symbol from there. This is how the application links to 2297 * dynamic linker services such as dlopen. 2298 */ 2299 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2300 res = symlook_obj(&req, &obj_rtld); 2301 if (res == 0) { 2302 def = req.sym_out; 2303 defobj = req.defobj_out; 2304 } 2305 } 2306 } else { 2307 assert(handle == RTLD_DEFAULT); 2308 res = symlook_default(&req, obj); 2309 if (res == 0) { 2310 defobj = req.defobj_out; 2311 def = req.sym_out; 2312 } 2313 } 2314 } else { 2315 if ((obj = dlcheck(handle)) == NULL) { 2316 lock_release(rtld_bind_lock, &lockstate); 2317 return NULL; 2318 } 2319 2320 donelist_init(&donelist); 2321 if (obj->mainprog) { 2322 /* Search main program and all libraries loaded by it. */ 2323 res = symlook_list(&req, &list_main, &donelist); 2324 if (res == 0) { 2325 def = req.sym_out; 2326 defobj = req.defobj_out; 2327 } else { 2328 /* 2329 * We do not distinguish between 'main' object and 2330 * global scope. If symbol is not defined by objects 2331 * loaded at startup, continue search among 2332 * dynamically loaded objects with RTLD_GLOBAL scope. 2333 */ 2334 res = symlook_list(&req, &list_global, &donelist); 2335 if (res == 0) { 2336 def = req.sym_out; 2337 defobj = req.defobj_out; 2338 } 2339 } 2340 } else { 2341 Needed_Entry fake; 2342 2343 /* Search the whole DAG rooted at the given object. */ 2344 fake.next = NULL; 2345 fake.obj = (Obj_Entry *)obj; 2346 fake.name = 0; 2347 res = symlook_needed(&req, &fake, &donelist); 2348 if (res == 0) { 2349 def = req.sym_out; 2350 defobj = req.defobj_out; 2351 } 2352 } 2353 } 2354 2355 if (def != NULL) { 2356 lock_release(rtld_bind_lock, &lockstate); 2357 2358 /* 2359 * The value required by the caller is derived from the value 2360 * of the symbol. For the ia64 architecture, we need to 2361 * construct a function descriptor which the caller can use to 2362 * call the function with the right 'gp' value. For other 2363 * architectures and for non-functions, the value is simply 2364 * the relocated value of the symbol. 2365 */ 2366 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2367 return make_function_pointer(def, defobj); 2368 else 2369 return defobj->relocbase + def->st_value; 2370 } 2371 2372 _rtld_error("Undefined symbol \"%s\"", name); 2373 lock_release(rtld_bind_lock, &lockstate); 2374 return NULL; 2375 } 2376 2377 void * 2378 dlsym(void *handle, const char *name) 2379 { 2380 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2381 SYMLOOK_DLSYM); 2382 } 2383 2384 dlfunc_t 2385 dlfunc(void *handle, const char *name) 2386 { 2387 union { 2388 void *d; 2389 dlfunc_t f; 2390 } rv; 2391 2392 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2393 SYMLOOK_DLSYM); 2394 return (rv.f); 2395 } 2396 2397 void * 2398 dlvsym(void *handle, const char *name, const char *version) 2399 { 2400 Ver_Entry ventry; 2401 2402 ventry.name = version; 2403 ventry.file = NULL; 2404 ventry.hash = elf_hash(version); 2405 ventry.flags= 0; 2406 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2407 SYMLOOK_DLSYM); 2408 } 2409 2410 int 2411 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2412 { 2413 const Obj_Entry *obj; 2414 RtldLockState lockstate; 2415 2416 rlock_acquire(rtld_bind_lock, &lockstate); 2417 obj = obj_from_addr(addr); 2418 if (obj == NULL) { 2419 _rtld_error("No shared object contains address"); 2420 lock_release(rtld_bind_lock, &lockstate); 2421 return (0); 2422 } 2423 rtld_fill_dl_phdr_info(obj, phdr_info); 2424 lock_release(rtld_bind_lock, &lockstate); 2425 return (1); 2426 } 2427 2428 int 2429 dladdr(const void *addr, Dl_info *info) 2430 { 2431 const Obj_Entry *obj; 2432 const Elf_Sym *def; 2433 void *symbol_addr; 2434 unsigned long symoffset; 2435 RtldLockState lockstate; 2436 2437 rlock_acquire(rtld_bind_lock, &lockstate); 2438 obj = obj_from_addr(addr); 2439 if (obj == NULL) { 2440 _rtld_error("No shared object contains address"); 2441 lock_release(rtld_bind_lock, &lockstate); 2442 return 0; 2443 } 2444 info->dli_fname = obj->path; 2445 info->dli_fbase = obj->mapbase; 2446 info->dli_saddr = (void *)0; 2447 info->dli_sname = NULL; 2448 2449 /* 2450 * Walk the symbol list looking for the symbol whose address is 2451 * closest to the address sent in. 2452 */ 2453 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2454 def = obj->symtab + symoffset; 2455 2456 /* 2457 * For skip the symbol if st_shndx is either SHN_UNDEF or 2458 * SHN_COMMON. 2459 */ 2460 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2461 continue; 2462 2463 /* 2464 * If the symbol is greater than the specified address, or if it 2465 * is further away from addr than the current nearest symbol, 2466 * then reject it. 2467 */ 2468 symbol_addr = obj->relocbase + def->st_value; 2469 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2470 continue; 2471 2472 /* Update our idea of the nearest symbol. */ 2473 info->dli_sname = obj->strtab + def->st_name; 2474 info->dli_saddr = symbol_addr; 2475 2476 /* Exact match? */ 2477 if (info->dli_saddr == addr) 2478 break; 2479 } 2480 lock_release(rtld_bind_lock, &lockstate); 2481 return 1; 2482 } 2483 2484 int 2485 dlinfo(void *handle, int request, void *p) 2486 { 2487 const Obj_Entry *obj; 2488 RtldLockState lockstate; 2489 int error; 2490 2491 rlock_acquire(rtld_bind_lock, &lockstate); 2492 2493 if (handle == NULL || handle == RTLD_SELF) { 2494 void *retaddr; 2495 2496 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2497 if ((obj = obj_from_addr(retaddr)) == NULL) 2498 _rtld_error("Cannot determine caller's shared object"); 2499 } else 2500 obj = dlcheck(handle); 2501 2502 if (obj == NULL) { 2503 lock_release(rtld_bind_lock, &lockstate); 2504 return (-1); 2505 } 2506 2507 error = 0; 2508 switch (request) { 2509 case RTLD_DI_LINKMAP: 2510 *((struct link_map const **)p) = &obj->linkmap; 2511 break; 2512 case RTLD_DI_ORIGIN: 2513 error = rtld_dirname(obj->path, p); 2514 break; 2515 2516 case RTLD_DI_SERINFOSIZE: 2517 case RTLD_DI_SERINFO: 2518 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2519 break; 2520 2521 default: 2522 _rtld_error("Invalid request %d passed to dlinfo()", request); 2523 error = -1; 2524 } 2525 2526 lock_release(rtld_bind_lock, &lockstate); 2527 2528 return (error); 2529 } 2530 2531 static void 2532 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2533 { 2534 2535 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2536 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2537 STAILQ_FIRST(&obj->names)->name : obj->path; 2538 phdr_info->dlpi_phdr = obj->phdr; 2539 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2540 phdr_info->dlpi_tls_modid = obj->tlsindex; 2541 phdr_info->dlpi_tls_data = obj->tlsinit; 2542 phdr_info->dlpi_adds = obj_loads; 2543 phdr_info->dlpi_subs = obj_loads - obj_count; 2544 } 2545 2546 int 2547 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2548 { 2549 struct dl_phdr_info phdr_info; 2550 const Obj_Entry *obj; 2551 RtldLockState bind_lockstate, phdr_lockstate; 2552 int error; 2553 2554 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2555 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2556 2557 error = 0; 2558 2559 for (obj = obj_list; obj != NULL; obj = obj->next) { 2560 rtld_fill_dl_phdr_info(obj, &phdr_info); 2561 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2562 break; 2563 2564 } 2565 lock_release(rtld_bind_lock, &bind_lockstate); 2566 lock_release(rtld_phdr_lock, &phdr_lockstate); 2567 2568 return (error); 2569 } 2570 2571 struct fill_search_info_args { 2572 int request; 2573 unsigned int flags; 2574 Dl_serinfo *serinfo; 2575 Dl_serpath *serpath; 2576 char *strspace; 2577 }; 2578 2579 static void * 2580 fill_search_info(const char *dir, size_t dirlen, void *param) 2581 { 2582 struct fill_search_info_args *arg; 2583 2584 arg = param; 2585 2586 if (arg->request == RTLD_DI_SERINFOSIZE) { 2587 arg->serinfo->dls_cnt ++; 2588 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2589 } else { 2590 struct dl_serpath *s_entry; 2591 2592 s_entry = arg->serpath; 2593 s_entry->dls_name = arg->strspace; 2594 s_entry->dls_flags = arg->flags; 2595 2596 strncpy(arg->strspace, dir, dirlen); 2597 arg->strspace[dirlen] = '\0'; 2598 2599 arg->strspace += dirlen + 1; 2600 arg->serpath++; 2601 } 2602 2603 return (NULL); 2604 } 2605 2606 static int 2607 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2608 { 2609 struct dl_serinfo _info; 2610 struct fill_search_info_args args; 2611 2612 args.request = RTLD_DI_SERINFOSIZE; 2613 args.serinfo = &_info; 2614 2615 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2616 _info.dls_cnt = 0; 2617 2618 path_enumerate(ld_library_path, fill_search_info, &args); 2619 path_enumerate(obj->rpath, fill_search_info, &args); 2620 path_enumerate(gethints(), fill_search_info, &args); 2621 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2622 2623 2624 if (request == RTLD_DI_SERINFOSIZE) { 2625 info->dls_size = _info.dls_size; 2626 info->dls_cnt = _info.dls_cnt; 2627 return (0); 2628 } 2629 2630 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2631 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2632 return (-1); 2633 } 2634 2635 args.request = RTLD_DI_SERINFO; 2636 args.serinfo = info; 2637 args.serpath = &info->dls_serpath[0]; 2638 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2639 2640 args.flags = LA_SER_LIBPATH; 2641 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2642 return (-1); 2643 2644 args.flags = LA_SER_RUNPATH; 2645 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2646 return (-1); 2647 2648 args.flags = LA_SER_CONFIG; 2649 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2650 return (-1); 2651 2652 args.flags = LA_SER_DEFAULT; 2653 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2654 return (-1); 2655 return (0); 2656 } 2657 2658 static int 2659 rtld_dirname(const char *path, char *bname) 2660 { 2661 const char *endp; 2662 2663 /* Empty or NULL string gets treated as "." */ 2664 if (path == NULL || *path == '\0') { 2665 bname[0] = '.'; 2666 bname[1] = '\0'; 2667 return (0); 2668 } 2669 2670 /* Strip trailing slashes */ 2671 endp = path + strlen(path) - 1; 2672 while (endp > path && *endp == '/') 2673 endp--; 2674 2675 /* Find the start of the dir */ 2676 while (endp > path && *endp != '/') 2677 endp--; 2678 2679 /* Either the dir is "/" or there are no slashes */ 2680 if (endp == path) { 2681 bname[0] = *endp == '/' ? '/' : '.'; 2682 bname[1] = '\0'; 2683 return (0); 2684 } else { 2685 do { 2686 endp--; 2687 } while (endp > path && *endp == '/'); 2688 } 2689 2690 if (endp - path + 2 > PATH_MAX) 2691 { 2692 _rtld_error("Filename is too long: %s", path); 2693 return(-1); 2694 } 2695 2696 strncpy(bname, path, endp - path + 1); 2697 bname[endp - path + 1] = '\0'; 2698 return (0); 2699 } 2700 2701 static int 2702 rtld_dirname_abs(const char *path, char *base) 2703 { 2704 char base_rel[PATH_MAX]; 2705 2706 if (rtld_dirname(path, base) == -1) 2707 return (-1); 2708 if (base[0] == '/') 2709 return (0); 2710 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2711 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2712 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2713 return (-1); 2714 strcpy(base, base_rel); 2715 return (0); 2716 } 2717 2718 static void 2719 linkmap_add(Obj_Entry *obj) 2720 { 2721 struct link_map *l = &obj->linkmap; 2722 struct link_map *prev; 2723 2724 obj->linkmap.l_name = obj->path; 2725 obj->linkmap.l_addr = obj->mapbase; 2726 obj->linkmap.l_ld = obj->dynamic; 2727 #ifdef __mips__ 2728 /* GDB needs load offset on MIPS to use the symbols */ 2729 obj->linkmap.l_offs = obj->relocbase; 2730 #endif 2731 2732 if (r_debug.r_map == NULL) { 2733 r_debug.r_map = l; 2734 return; 2735 } 2736 2737 /* 2738 * Scan to the end of the list, but not past the entry for the 2739 * dynamic linker, which we want to keep at the very end. 2740 */ 2741 for (prev = r_debug.r_map; 2742 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2743 prev = prev->l_next) 2744 ; 2745 2746 /* Link in the new entry. */ 2747 l->l_prev = prev; 2748 l->l_next = prev->l_next; 2749 if (l->l_next != NULL) 2750 l->l_next->l_prev = l; 2751 prev->l_next = l; 2752 } 2753 2754 static void 2755 linkmap_delete(Obj_Entry *obj) 2756 { 2757 struct link_map *l = &obj->linkmap; 2758 2759 if (l->l_prev == NULL) { 2760 if ((r_debug.r_map = l->l_next) != NULL) 2761 l->l_next->l_prev = NULL; 2762 return; 2763 } 2764 2765 if ((l->l_prev->l_next = l->l_next) != NULL) 2766 l->l_next->l_prev = l->l_prev; 2767 } 2768 2769 /* 2770 * Function for the debugger to set a breakpoint on to gain control. 2771 * 2772 * The two parameters allow the debugger to easily find and determine 2773 * what the runtime loader is doing and to whom it is doing it. 2774 * 2775 * When the loadhook trap is hit (r_debug_state, set at program 2776 * initialization), the arguments can be found on the stack: 2777 * 2778 * +8 struct link_map *m 2779 * +4 struct r_debug *rd 2780 * +0 RetAddr 2781 */ 2782 void 2783 r_debug_state(struct r_debug* rd, struct link_map *m) 2784 { 2785 } 2786 2787 /* 2788 * Get address of the pointer variable in the main program. 2789 * Prefer non-weak symbol over the weak one. 2790 */ 2791 static const void ** 2792 get_program_var_addr(const char *name, RtldLockState *lockstate) 2793 { 2794 SymLook req; 2795 DoneList donelist; 2796 2797 symlook_init(&req, name); 2798 req.lockstate = lockstate; 2799 donelist_init(&donelist); 2800 if (symlook_global(&req, &donelist) != 0) 2801 return (NULL); 2802 return ((const void **)(req.defobj_out->relocbase + req.sym_out->st_value)); 2803 } 2804 2805 /* 2806 * Set a pointer variable in the main program to the given value. This 2807 * is used to set key variables such as "environ" before any of the 2808 * init functions are called. 2809 */ 2810 static void 2811 set_program_var(const char *name, const void *value) 2812 { 2813 const void **addr; 2814 2815 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 2816 dbg("\"%s\": *%p <-- %p", name, addr, value); 2817 *addr = value; 2818 } 2819 } 2820 2821 /* 2822 * Search the global objects, including dependencies and main object, 2823 * for the given symbol. 2824 */ 2825 static int 2826 symlook_global(SymLook *req, DoneList *donelist) 2827 { 2828 SymLook req1; 2829 const Objlist_Entry *elm; 2830 int res; 2831 2832 symlook_init_from_req(&req1, req); 2833 2834 /* Search all objects loaded at program start up. */ 2835 if (req->defobj_out == NULL || 2836 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2837 res = symlook_list(&req1, &list_main, donelist); 2838 if (res == 0 && (req->defobj_out == NULL || 2839 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2840 req->sym_out = req1.sym_out; 2841 req->defobj_out = req1.defobj_out; 2842 assert(req->defobj_out != NULL); 2843 } 2844 } 2845 2846 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2847 STAILQ_FOREACH(elm, &list_global, link) { 2848 if (req->defobj_out != NULL && 2849 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2850 break; 2851 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 2852 if (res == 0 && (req->defobj_out == NULL || 2853 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2854 req->sym_out = req1.sym_out; 2855 req->defobj_out = req1.defobj_out; 2856 assert(req->defobj_out != NULL); 2857 } 2858 } 2859 2860 return (req->sym_out != NULL ? 0 : ESRCH); 2861 } 2862 2863 /* 2864 * Given a symbol name in a referencing object, find the corresponding 2865 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2866 * no definition was found. Returns a pointer to the Obj_Entry of the 2867 * defining object via the reference parameter DEFOBJ_OUT. 2868 */ 2869 static int 2870 symlook_default(SymLook *req, const Obj_Entry *refobj) 2871 { 2872 DoneList donelist; 2873 const Objlist_Entry *elm; 2874 SymLook req1; 2875 int res; 2876 2877 donelist_init(&donelist); 2878 symlook_init_from_req(&req1, req); 2879 2880 /* Look first in the referencing object if linked symbolically. */ 2881 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2882 res = symlook_obj(&req1, refobj); 2883 if (res == 0) { 2884 req->sym_out = req1.sym_out; 2885 req->defobj_out = req1.defobj_out; 2886 assert(req->defobj_out != NULL); 2887 } 2888 } 2889 2890 symlook_global(req, &donelist); 2891 2892 /* Search all dlopened DAGs containing the referencing object. */ 2893 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2894 if (req->sym_out != NULL && 2895 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2896 break; 2897 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 2898 if (res == 0 && (req->sym_out == NULL || 2899 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2900 req->sym_out = req1.sym_out; 2901 req->defobj_out = req1.defobj_out; 2902 assert(req->defobj_out != NULL); 2903 } 2904 } 2905 2906 /* 2907 * Search the dynamic linker itself, and possibly resolve the 2908 * symbol from there. This is how the application links to 2909 * dynamic linker services such as dlopen. 2910 */ 2911 if (req->sym_out == NULL || 2912 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2913 res = symlook_obj(&req1, &obj_rtld); 2914 if (res == 0) { 2915 req->sym_out = req1.sym_out; 2916 req->defobj_out = req1.defobj_out; 2917 assert(req->defobj_out != NULL); 2918 } 2919 } 2920 2921 return (req->sym_out != NULL ? 0 : ESRCH); 2922 } 2923 2924 static int 2925 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 2926 { 2927 const Elf_Sym *def; 2928 const Obj_Entry *defobj; 2929 const Objlist_Entry *elm; 2930 SymLook req1; 2931 int res; 2932 2933 def = NULL; 2934 defobj = NULL; 2935 STAILQ_FOREACH(elm, objlist, link) { 2936 if (donelist_check(dlp, elm->obj)) 2937 continue; 2938 symlook_init_from_req(&req1, req); 2939 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 2940 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 2941 def = req1.sym_out; 2942 defobj = req1.defobj_out; 2943 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2944 break; 2945 } 2946 } 2947 } 2948 if (def != NULL) { 2949 req->sym_out = def; 2950 req->defobj_out = defobj; 2951 return (0); 2952 } 2953 return (ESRCH); 2954 } 2955 2956 /* 2957 * Search the symbol table of a shared object and all objects needed 2958 * by it for a symbol of the given name. Search order is 2959 * breadth-first. Returns a pointer to the symbol, or NULL if no 2960 * definition was found. 2961 */ 2962 static int 2963 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 2964 { 2965 const Elf_Sym *def, *def_w; 2966 const Needed_Entry *n; 2967 const Obj_Entry *defobj, *defobj1; 2968 SymLook req1; 2969 int res; 2970 2971 def = def_w = NULL; 2972 defobj = NULL; 2973 symlook_init_from_req(&req1, req); 2974 for (n = needed; n != NULL; n = n->next) { 2975 if (n->obj == NULL || donelist_check(dlp, n->obj) || 2976 (res = symlook_obj(&req1, n->obj)) != 0) 2977 continue; 2978 def = req1.sym_out; 2979 defobj = req1.defobj_out; 2980 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2981 req->defobj_out = defobj; 2982 req->sym_out = def; 2983 return (0); 2984 } 2985 } 2986 /* 2987 * There we come when either symbol definition is not found in 2988 * directly needed objects, or found symbol is weak. 2989 */ 2990 for (n = needed; n != NULL; n = n->next) { 2991 if (n->obj == NULL) 2992 continue; 2993 res = symlook_needed(&req1, n->obj->needed, dlp); 2994 if (res != 0) 2995 continue; 2996 def_w = req1.sym_out; 2997 defobj1 = req1.defobj_out; 2998 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2999 def = def_w; 3000 defobj = defobj1; 3001 } 3002 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 3003 break; 3004 } 3005 if (def != NULL) { 3006 req->sym_out = def; 3007 req->defobj_out = defobj; 3008 return (0); 3009 } 3010 return (ESRCH); 3011 } 3012 3013 /* 3014 * Search the symbol table of a single shared object for a symbol of 3015 * the given name and version, if requested. Returns a pointer to the 3016 * symbol, or NULL if no definition was found. If the object is 3017 * filter, return filtered symbol from filtee. 3018 * 3019 * The symbol's hash value is passed in for efficiency reasons; that 3020 * eliminates many recomputations of the hash value. 3021 */ 3022 int 3023 symlook_obj(SymLook *req, const Obj_Entry *obj) 3024 { 3025 DoneList donelist; 3026 SymLook req1; 3027 int res, mres; 3028 3029 mres = symlook_obj1(req, obj); 3030 if (mres == 0) { 3031 if (obj->needed_filtees != NULL) { 3032 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3033 donelist_init(&donelist); 3034 symlook_init_from_req(&req1, req); 3035 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3036 if (res == 0) { 3037 req->sym_out = req1.sym_out; 3038 req->defobj_out = req1.defobj_out; 3039 } 3040 return (res); 3041 } 3042 if (obj->needed_aux_filtees != NULL) { 3043 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3044 donelist_init(&donelist); 3045 symlook_init_from_req(&req1, req); 3046 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3047 if (res == 0) { 3048 req->sym_out = req1.sym_out; 3049 req->defobj_out = req1.defobj_out; 3050 return (res); 3051 } 3052 } 3053 } 3054 return (mres); 3055 } 3056 3057 static int 3058 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3059 { 3060 unsigned long symnum; 3061 const Elf_Sym *vsymp; 3062 Elf_Versym verndx; 3063 int vcount; 3064 3065 if (obj->buckets == NULL) 3066 return (ESRCH); 3067 3068 vsymp = NULL; 3069 vcount = 0; 3070 symnum = obj->buckets[req->hash % obj->nbuckets]; 3071 3072 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3073 const Elf_Sym *symp; 3074 const char *strp; 3075 3076 if (symnum >= obj->nchains) 3077 return (ESRCH); /* Bad object */ 3078 3079 symp = obj->symtab + symnum; 3080 strp = obj->strtab + symp->st_name; 3081 3082 switch (ELF_ST_TYPE(symp->st_info)) { 3083 case STT_FUNC: 3084 case STT_NOTYPE: 3085 case STT_OBJECT: 3086 if (symp->st_value == 0) 3087 continue; 3088 /* fallthrough */ 3089 case STT_TLS: 3090 if (symp->st_shndx != SHN_UNDEF) 3091 break; 3092 #ifndef __mips__ 3093 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3094 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3095 break; 3096 /* fallthrough */ 3097 #endif 3098 default: 3099 continue; 3100 } 3101 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3102 continue; 3103 3104 if (req->ventry == NULL) { 3105 if (obj->versyms != NULL) { 3106 verndx = VER_NDX(obj->versyms[symnum]); 3107 if (verndx > obj->vernum) { 3108 _rtld_error("%s: symbol %s references wrong version %d", 3109 obj->path, obj->strtab + symnum, verndx); 3110 continue; 3111 } 3112 /* 3113 * If we are not called from dlsym (i.e. this is a normal 3114 * relocation from unversioned binary), accept the symbol 3115 * immediately if it happens to have first version after 3116 * this shared object became versioned. Otherwise, if 3117 * symbol is versioned and not hidden, remember it. If it 3118 * is the only symbol with this name exported by the 3119 * shared object, it will be returned as a match at the 3120 * end of the function. If symbol is global (verndx < 2) 3121 * accept it unconditionally. 3122 */ 3123 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3124 verndx == VER_NDX_GIVEN) { 3125 req->sym_out = symp; 3126 req->defobj_out = obj; 3127 return (0); 3128 } 3129 else if (verndx >= VER_NDX_GIVEN) { 3130 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3131 if (vsymp == NULL) 3132 vsymp = symp; 3133 vcount ++; 3134 } 3135 continue; 3136 } 3137 } 3138 req->sym_out = symp; 3139 req->defobj_out = obj; 3140 return (0); 3141 } else { 3142 if (obj->versyms == NULL) { 3143 if (object_match_name(obj, req->ventry->name)) { 3144 _rtld_error("%s: object %s should provide version %s for " 3145 "symbol %s", obj_rtld.path, obj->path, 3146 req->ventry->name, obj->strtab + symnum); 3147 continue; 3148 } 3149 } else { 3150 verndx = VER_NDX(obj->versyms[symnum]); 3151 if (verndx > obj->vernum) { 3152 _rtld_error("%s: symbol %s references wrong version %d", 3153 obj->path, obj->strtab + symnum, verndx); 3154 continue; 3155 } 3156 if (obj->vertab[verndx].hash != req->ventry->hash || 3157 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3158 /* 3159 * Version does not match. Look if this is a global symbol 3160 * and if it is not hidden. If global symbol (verndx < 2) 3161 * is available, use it. Do not return symbol if we are 3162 * called by dlvsym, because dlvsym looks for a specific 3163 * version and default one is not what dlvsym wants. 3164 */ 3165 if ((req->flags & SYMLOOK_DLSYM) || 3166 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3167 (verndx >= VER_NDX_GIVEN)) 3168 continue; 3169 } 3170 } 3171 req->sym_out = symp; 3172 req->defobj_out = obj; 3173 return (0); 3174 } 3175 } 3176 if (vcount == 1) { 3177 req->sym_out = vsymp; 3178 req->defobj_out = obj; 3179 return (0); 3180 } 3181 return (ESRCH); 3182 } 3183 3184 static void 3185 trace_loaded_objects(Obj_Entry *obj) 3186 { 3187 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3188 int c; 3189 3190 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3191 main_local = ""; 3192 3193 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3194 fmt1 = "\t%o => %p (%x)\n"; 3195 3196 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3197 fmt2 = "\t%o (%x)\n"; 3198 3199 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3200 3201 for (; obj; obj = obj->next) { 3202 Needed_Entry *needed; 3203 char *name, *path; 3204 bool is_lib; 3205 3206 if (list_containers && obj->needed != NULL) 3207 printf("%s:\n", obj->path); 3208 for (needed = obj->needed; needed; needed = needed->next) { 3209 if (needed->obj != NULL) { 3210 if (needed->obj->traced && !list_containers) 3211 continue; 3212 needed->obj->traced = true; 3213 path = needed->obj->path; 3214 } else 3215 path = "not found"; 3216 3217 name = (char *)obj->strtab + needed->name; 3218 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3219 3220 fmt = is_lib ? fmt1 : fmt2; 3221 while ((c = *fmt++) != '\0') { 3222 switch (c) { 3223 default: 3224 putchar(c); 3225 continue; 3226 case '\\': 3227 switch (c = *fmt) { 3228 case '\0': 3229 continue; 3230 case 'n': 3231 putchar('\n'); 3232 break; 3233 case 't': 3234 putchar('\t'); 3235 break; 3236 } 3237 break; 3238 case '%': 3239 switch (c = *fmt) { 3240 case '\0': 3241 continue; 3242 case '%': 3243 default: 3244 putchar(c); 3245 break; 3246 case 'A': 3247 printf("%s", main_local); 3248 break; 3249 case 'a': 3250 printf("%s", obj_main->path); 3251 break; 3252 case 'o': 3253 printf("%s", name); 3254 break; 3255 #if 0 3256 case 'm': 3257 printf("%d", sodp->sod_major); 3258 break; 3259 case 'n': 3260 printf("%d", sodp->sod_minor); 3261 break; 3262 #endif 3263 case 'p': 3264 printf("%s", path); 3265 break; 3266 case 'x': 3267 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3268 break; 3269 } 3270 break; 3271 } 3272 ++fmt; 3273 } 3274 } 3275 } 3276 } 3277 3278 /* 3279 * Unload a dlopened object and its dependencies from memory and from 3280 * our data structures. It is assumed that the DAG rooted in the 3281 * object has already been unreferenced, and that the object has a 3282 * reference count of 0. 3283 */ 3284 static void 3285 unload_object(Obj_Entry *root) 3286 { 3287 Obj_Entry *obj; 3288 Obj_Entry **linkp; 3289 3290 assert(root->refcount == 0); 3291 3292 /* 3293 * Pass over the DAG removing unreferenced objects from 3294 * appropriate lists. 3295 */ 3296 unlink_object(root); 3297 3298 /* Unmap all objects that are no longer referenced. */ 3299 linkp = &obj_list->next; 3300 while ((obj = *linkp) != NULL) { 3301 if (obj->refcount == 0) { 3302 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3303 obj->path); 3304 dbg("unloading \"%s\"", obj->path); 3305 unload_filtees(root); 3306 munmap(obj->mapbase, obj->mapsize); 3307 linkmap_delete(obj); 3308 *linkp = obj->next; 3309 obj_count--; 3310 obj_free(obj); 3311 } else 3312 linkp = &obj->next; 3313 } 3314 obj_tail = linkp; 3315 } 3316 3317 static void 3318 unlink_object(Obj_Entry *root) 3319 { 3320 Objlist_Entry *elm; 3321 3322 if (root->refcount == 0) { 3323 /* Remove the object from the RTLD_GLOBAL list. */ 3324 objlist_remove(&list_global, root); 3325 3326 /* Remove the object from all objects' DAG lists. */ 3327 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3328 objlist_remove(&elm->obj->dldags, root); 3329 if (elm->obj != root) 3330 unlink_object(elm->obj); 3331 } 3332 } 3333 } 3334 3335 static void 3336 ref_dag(Obj_Entry *root) 3337 { 3338 Objlist_Entry *elm; 3339 3340 assert(root->dag_inited); 3341 STAILQ_FOREACH(elm, &root->dagmembers, link) 3342 elm->obj->refcount++; 3343 } 3344 3345 static void 3346 unref_dag(Obj_Entry *root) 3347 { 3348 Objlist_Entry *elm; 3349 3350 assert(root->dag_inited); 3351 STAILQ_FOREACH(elm, &root->dagmembers, link) 3352 elm->obj->refcount--; 3353 } 3354 3355 /* 3356 * Common code for MD __tls_get_addr(). 3357 */ 3358 void * 3359 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3360 { 3361 Elf_Addr* dtv = *dtvp; 3362 RtldLockState lockstate; 3363 3364 /* Check dtv generation in case new modules have arrived */ 3365 if (dtv[0] != tls_dtv_generation) { 3366 Elf_Addr* newdtv; 3367 int to_copy; 3368 3369 wlock_acquire(rtld_bind_lock, &lockstate); 3370 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3371 to_copy = dtv[1]; 3372 if (to_copy > tls_max_index) 3373 to_copy = tls_max_index; 3374 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3375 newdtv[0] = tls_dtv_generation; 3376 newdtv[1] = tls_max_index; 3377 free(dtv); 3378 lock_release(rtld_bind_lock, &lockstate); 3379 *dtvp = newdtv; 3380 } 3381 3382 /* Dynamically allocate module TLS if necessary */ 3383 if (!dtv[index + 1]) { 3384 /* Signal safe, wlock will block out signals. */ 3385 wlock_acquire(rtld_bind_lock, &lockstate); 3386 if (!dtv[index + 1]) 3387 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3388 lock_release(rtld_bind_lock, &lockstate); 3389 } 3390 return (void*) (dtv[index + 1] + offset); 3391 } 3392 3393 /* XXX not sure what variants to use for arm. */ 3394 3395 #if defined(__ia64__) || defined(__powerpc__) 3396 3397 /* 3398 * Allocate Static TLS using the Variant I method. 3399 */ 3400 void * 3401 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3402 { 3403 Obj_Entry *obj; 3404 char *tcb; 3405 Elf_Addr **tls; 3406 Elf_Addr *dtv; 3407 Elf_Addr addr; 3408 int i; 3409 3410 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3411 return (oldtcb); 3412 3413 assert(tcbsize >= TLS_TCB_SIZE); 3414 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3415 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3416 3417 if (oldtcb != NULL) { 3418 memcpy(tls, oldtcb, tls_static_space); 3419 free(oldtcb); 3420 3421 /* Adjust the DTV. */ 3422 dtv = tls[0]; 3423 for (i = 0; i < dtv[1]; i++) { 3424 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3425 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3426 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3427 } 3428 } 3429 } else { 3430 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3431 tls[0] = dtv; 3432 dtv[0] = tls_dtv_generation; 3433 dtv[1] = tls_max_index; 3434 3435 for (obj = objs; obj; obj = obj->next) { 3436 if (obj->tlsoffset > 0) { 3437 addr = (Elf_Addr)tls + obj->tlsoffset; 3438 if (obj->tlsinitsize > 0) 3439 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3440 if (obj->tlssize > obj->tlsinitsize) 3441 memset((void*) (addr + obj->tlsinitsize), 0, 3442 obj->tlssize - obj->tlsinitsize); 3443 dtv[obj->tlsindex + 1] = addr; 3444 } 3445 } 3446 } 3447 3448 return (tcb); 3449 } 3450 3451 void 3452 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3453 { 3454 Elf_Addr *dtv; 3455 Elf_Addr tlsstart, tlsend; 3456 int dtvsize, i; 3457 3458 assert(tcbsize >= TLS_TCB_SIZE); 3459 3460 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3461 tlsend = tlsstart + tls_static_space; 3462 3463 dtv = *(Elf_Addr **)tlsstart; 3464 dtvsize = dtv[1]; 3465 for (i = 0; i < dtvsize; i++) { 3466 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3467 free((void*)dtv[i+2]); 3468 } 3469 } 3470 free(dtv); 3471 free(tcb); 3472 } 3473 3474 #endif 3475 3476 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3477 defined(__arm__) || defined(__mips__) 3478 3479 /* 3480 * Allocate Static TLS using the Variant II method. 3481 */ 3482 void * 3483 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3484 { 3485 Obj_Entry *obj; 3486 size_t size; 3487 char *tls; 3488 Elf_Addr *dtv, *olddtv; 3489 Elf_Addr segbase, oldsegbase, addr; 3490 int i; 3491 3492 size = round(tls_static_space, tcbalign); 3493 3494 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3495 tls = calloc(1, size + tcbsize); 3496 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3497 3498 segbase = (Elf_Addr)(tls + size); 3499 ((Elf_Addr*)segbase)[0] = segbase; 3500 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3501 3502 dtv[0] = tls_dtv_generation; 3503 dtv[1] = tls_max_index; 3504 3505 if (oldtls) { 3506 /* 3507 * Copy the static TLS block over whole. 3508 */ 3509 oldsegbase = (Elf_Addr) oldtls; 3510 memcpy((void *)(segbase - tls_static_space), 3511 (const void *)(oldsegbase - tls_static_space), 3512 tls_static_space); 3513 3514 /* 3515 * If any dynamic TLS blocks have been created tls_get_addr(), 3516 * move them over. 3517 */ 3518 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3519 for (i = 0; i < olddtv[1]; i++) { 3520 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3521 dtv[i+2] = olddtv[i+2]; 3522 olddtv[i+2] = 0; 3523 } 3524 } 3525 3526 /* 3527 * We assume that this block was the one we created with 3528 * allocate_initial_tls(). 3529 */ 3530 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3531 } else { 3532 for (obj = objs; obj; obj = obj->next) { 3533 if (obj->tlsoffset) { 3534 addr = segbase - obj->tlsoffset; 3535 memset((void*) (addr + obj->tlsinitsize), 3536 0, obj->tlssize - obj->tlsinitsize); 3537 if (obj->tlsinit) 3538 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3539 dtv[obj->tlsindex + 1] = addr; 3540 } 3541 } 3542 } 3543 3544 return (void*) segbase; 3545 } 3546 3547 void 3548 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3549 { 3550 size_t size; 3551 Elf_Addr* dtv; 3552 int dtvsize, i; 3553 Elf_Addr tlsstart, tlsend; 3554 3555 /* 3556 * Figure out the size of the initial TLS block so that we can 3557 * find stuff which ___tls_get_addr() allocated dynamically. 3558 */ 3559 size = round(tls_static_space, tcbalign); 3560 3561 dtv = ((Elf_Addr**)tls)[1]; 3562 dtvsize = dtv[1]; 3563 tlsend = (Elf_Addr) tls; 3564 tlsstart = tlsend - size; 3565 for (i = 0; i < dtvsize; i++) { 3566 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3567 free((void*) dtv[i+2]); 3568 } 3569 } 3570 3571 free((void*) tlsstart); 3572 free((void*) dtv); 3573 } 3574 3575 #endif 3576 3577 /* 3578 * Allocate TLS block for module with given index. 3579 */ 3580 void * 3581 allocate_module_tls(int index) 3582 { 3583 Obj_Entry* obj; 3584 char* p; 3585 3586 for (obj = obj_list; obj; obj = obj->next) { 3587 if (obj->tlsindex == index) 3588 break; 3589 } 3590 if (!obj) { 3591 _rtld_error("Can't find module with TLS index %d", index); 3592 die(); 3593 } 3594 3595 p = malloc(obj->tlssize); 3596 if (p == NULL) { 3597 _rtld_error("Cannot allocate TLS block for index %d", index); 3598 die(); 3599 } 3600 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3601 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3602 3603 return p; 3604 } 3605 3606 bool 3607 allocate_tls_offset(Obj_Entry *obj) 3608 { 3609 size_t off; 3610 3611 if (obj->tls_done) 3612 return true; 3613 3614 if (obj->tlssize == 0) { 3615 obj->tls_done = true; 3616 return true; 3617 } 3618 3619 if (obj->tlsindex == 1) 3620 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3621 else 3622 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3623 obj->tlssize, obj->tlsalign); 3624 3625 /* 3626 * If we have already fixed the size of the static TLS block, we 3627 * must stay within that size. When allocating the static TLS, we 3628 * leave a small amount of space spare to be used for dynamically 3629 * loading modules which use static TLS. 3630 */ 3631 if (tls_static_space) { 3632 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3633 return false; 3634 } 3635 3636 tls_last_offset = obj->tlsoffset = off; 3637 tls_last_size = obj->tlssize; 3638 obj->tls_done = true; 3639 3640 return true; 3641 } 3642 3643 void 3644 free_tls_offset(Obj_Entry *obj) 3645 { 3646 3647 /* 3648 * If we were the last thing to allocate out of the static TLS 3649 * block, we give our space back to the 'allocator'. This is a 3650 * simplistic workaround to allow libGL.so.1 to be loaded and 3651 * unloaded multiple times. 3652 */ 3653 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3654 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3655 tls_last_offset -= obj->tlssize; 3656 tls_last_size = 0; 3657 } 3658 } 3659 3660 void * 3661 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3662 { 3663 void *ret; 3664 RtldLockState lockstate; 3665 3666 wlock_acquire(rtld_bind_lock, &lockstate); 3667 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3668 lock_release(rtld_bind_lock, &lockstate); 3669 return (ret); 3670 } 3671 3672 void 3673 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3674 { 3675 RtldLockState lockstate; 3676 3677 wlock_acquire(rtld_bind_lock, &lockstate); 3678 free_tls(tcb, tcbsize, tcbalign); 3679 lock_release(rtld_bind_lock, &lockstate); 3680 } 3681 3682 static void 3683 object_add_name(Obj_Entry *obj, const char *name) 3684 { 3685 Name_Entry *entry; 3686 size_t len; 3687 3688 len = strlen(name); 3689 entry = malloc(sizeof(Name_Entry) + len); 3690 3691 if (entry != NULL) { 3692 strcpy(entry->name, name); 3693 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3694 } 3695 } 3696 3697 static int 3698 object_match_name(const Obj_Entry *obj, const char *name) 3699 { 3700 Name_Entry *entry; 3701 3702 STAILQ_FOREACH(entry, &obj->names, link) { 3703 if (strcmp(name, entry->name) == 0) 3704 return (1); 3705 } 3706 return (0); 3707 } 3708 3709 static Obj_Entry * 3710 locate_dependency(const Obj_Entry *obj, const char *name) 3711 { 3712 const Objlist_Entry *entry; 3713 const Needed_Entry *needed; 3714 3715 STAILQ_FOREACH(entry, &list_main, link) { 3716 if (object_match_name(entry->obj, name)) 3717 return entry->obj; 3718 } 3719 3720 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3721 if (needed->obj == NULL) 3722 continue; 3723 if (object_match_name(needed->obj, name)) 3724 return needed->obj; 3725 } 3726 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3727 obj->path, name); 3728 die(); 3729 } 3730 3731 static int 3732 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3733 const Elf_Vernaux *vna) 3734 { 3735 const Elf_Verdef *vd; 3736 const char *vername; 3737 3738 vername = refobj->strtab + vna->vna_name; 3739 vd = depobj->verdef; 3740 if (vd == NULL) { 3741 _rtld_error("%s: version %s required by %s not defined", 3742 depobj->path, vername, refobj->path); 3743 return (-1); 3744 } 3745 for (;;) { 3746 if (vd->vd_version != VER_DEF_CURRENT) { 3747 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3748 depobj->path, vd->vd_version); 3749 return (-1); 3750 } 3751 if (vna->vna_hash == vd->vd_hash) { 3752 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3753 ((char *)vd + vd->vd_aux); 3754 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3755 return (0); 3756 } 3757 if (vd->vd_next == 0) 3758 break; 3759 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3760 } 3761 if (vna->vna_flags & VER_FLG_WEAK) 3762 return (0); 3763 _rtld_error("%s: version %s required by %s not found", 3764 depobj->path, vername, refobj->path); 3765 return (-1); 3766 } 3767 3768 static int 3769 rtld_verify_object_versions(Obj_Entry *obj) 3770 { 3771 const Elf_Verneed *vn; 3772 const Elf_Verdef *vd; 3773 const Elf_Verdaux *vda; 3774 const Elf_Vernaux *vna; 3775 const Obj_Entry *depobj; 3776 int maxvernum, vernum; 3777 3778 maxvernum = 0; 3779 /* 3780 * Walk over defined and required version records and figure out 3781 * max index used by any of them. Do very basic sanity checking 3782 * while there. 3783 */ 3784 vn = obj->verneed; 3785 while (vn != NULL) { 3786 if (vn->vn_version != VER_NEED_CURRENT) { 3787 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3788 obj->path, vn->vn_version); 3789 return (-1); 3790 } 3791 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3792 for (;;) { 3793 vernum = VER_NEED_IDX(vna->vna_other); 3794 if (vernum > maxvernum) 3795 maxvernum = vernum; 3796 if (vna->vna_next == 0) 3797 break; 3798 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3799 } 3800 if (vn->vn_next == 0) 3801 break; 3802 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3803 } 3804 3805 vd = obj->verdef; 3806 while (vd != NULL) { 3807 if (vd->vd_version != VER_DEF_CURRENT) { 3808 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3809 obj->path, vd->vd_version); 3810 return (-1); 3811 } 3812 vernum = VER_DEF_IDX(vd->vd_ndx); 3813 if (vernum > maxvernum) 3814 maxvernum = vernum; 3815 if (vd->vd_next == 0) 3816 break; 3817 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3818 } 3819 3820 if (maxvernum == 0) 3821 return (0); 3822 3823 /* 3824 * Store version information in array indexable by version index. 3825 * Verify that object version requirements are satisfied along the 3826 * way. 3827 */ 3828 obj->vernum = maxvernum + 1; 3829 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3830 3831 vd = obj->verdef; 3832 while (vd != NULL) { 3833 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3834 vernum = VER_DEF_IDX(vd->vd_ndx); 3835 assert(vernum <= maxvernum); 3836 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3837 obj->vertab[vernum].hash = vd->vd_hash; 3838 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3839 obj->vertab[vernum].file = NULL; 3840 obj->vertab[vernum].flags = 0; 3841 } 3842 if (vd->vd_next == 0) 3843 break; 3844 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3845 } 3846 3847 vn = obj->verneed; 3848 while (vn != NULL) { 3849 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3850 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3851 for (;;) { 3852 if (check_object_provided_version(obj, depobj, vna)) 3853 return (-1); 3854 vernum = VER_NEED_IDX(vna->vna_other); 3855 assert(vernum <= maxvernum); 3856 obj->vertab[vernum].hash = vna->vna_hash; 3857 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3858 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3859 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3860 VER_INFO_HIDDEN : 0; 3861 if (vna->vna_next == 0) 3862 break; 3863 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3864 } 3865 if (vn->vn_next == 0) 3866 break; 3867 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3868 } 3869 return 0; 3870 } 3871 3872 static int 3873 rtld_verify_versions(const Objlist *objlist) 3874 { 3875 Objlist_Entry *entry; 3876 int rc; 3877 3878 rc = 0; 3879 STAILQ_FOREACH(entry, objlist, link) { 3880 /* 3881 * Skip dummy objects or objects that have their version requirements 3882 * already checked. 3883 */ 3884 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3885 continue; 3886 if (rtld_verify_object_versions(entry->obj) == -1) { 3887 rc = -1; 3888 if (ld_tracing == NULL) 3889 break; 3890 } 3891 } 3892 if (rc == 0 || ld_tracing != NULL) 3893 rc = rtld_verify_object_versions(&obj_rtld); 3894 return rc; 3895 } 3896 3897 const Ver_Entry * 3898 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3899 { 3900 Elf_Versym vernum; 3901 3902 if (obj->vertab) { 3903 vernum = VER_NDX(obj->versyms[symnum]); 3904 if (vernum >= obj->vernum) { 3905 _rtld_error("%s: symbol %s has wrong verneed value %d", 3906 obj->path, obj->strtab + symnum, vernum); 3907 } else if (obj->vertab[vernum].hash != 0) { 3908 return &obj->vertab[vernum]; 3909 } 3910 } 3911 return NULL; 3912 } 3913 3914 int 3915 _rtld_get_stack_prot(void) 3916 { 3917 3918 return (stack_prot); 3919 } 3920 3921 static void 3922 map_stacks_exec(RtldLockState *lockstate) 3923 { 3924 void (*thr_map_stacks_exec)(void); 3925 3926 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 3927 return; 3928 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 3929 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 3930 if (thr_map_stacks_exec != NULL) { 3931 stack_prot |= PROT_EXEC; 3932 thr_map_stacks_exec(); 3933 } 3934 } 3935 3936 void 3937 symlook_init(SymLook *dst, const char *name) 3938 { 3939 3940 bzero(dst, sizeof(*dst)); 3941 dst->name = name; 3942 dst->hash = elf_hash(name); 3943 } 3944 3945 static void 3946 symlook_init_from_req(SymLook *dst, const SymLook *src) 3947 { 3948 3949 dst->name = src->name; 3950 dst->hash = src->hash; 3951 dst->ventry = src->ventry; 3952 dst->flags = src->flags; 3953 dst->defobj_out = NULL; 3954 dst->sym_out = NULL; 3955 dst->lockstate = src->lockstate; 3956 } 3957 3958 /* 3959 * Overrides for libc_pic-provided functions. 3960 */ 3961 3962 int 3963 __getosreldate(void) 3964 { 3965 size_t len; 3966 int oid[2]; 3967 int error, osrel; 3968 3969 if (osreldate != 0) 3970 return (osreldate); 3971 3972 oid[0] = CTL_KERN; 3973 oid[1] = KERN_OSRELDATE; 3974 osrel = 0; 3975 len = sizeof(osrel); 3976 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 3977 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 3978 osreldate = osrel; 3979 return (osreldate); 3980 } 3981 3982 /* 3983 * No unresolved symbols for rtld. 3984 */ 3985 void 3986 __pthread_cxa_finalize(struct dl_phdr_info *a) 3987 { 3988 } 3989