1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD: src/libexec/rtld-elf/rtld.c,v 1.173 2011/02/09 09:20:27 kib Exp $ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mount.h> 42 #include <sys/mman.h> 43 #include <sys/stat.h> 44 #include <sys/uio.h> 45 #include <sys/utsname.h> 46 #include <sys/ktrace.h> 47 #include <sys/resident.h> 48 #include <sys/tls.h> 49 50 #include <machine/tls.h> 51 52 #include <dlfcn.h> 53 #include <err.h> 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <stdarg.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <unistd.h> 61 62 #include "debug.h" 63 #include "rtld.h" 64 #include "libmap.h" 65 66 #define PATH_RTLD "/usr/libexec/ld-elf.so.2" 67 #define LD_ARY_CACHE 16 68 69 /* Types. */ 70 typedef void (*func_ptr_type)(); 71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73 /* 74 * This structure provides a reentrant way to keep a list of objects and 75 * check which ones have already been processed in some way. 76 */ 77 typedef struct Struct_DoneList { 78 const Obj_Entry **objs; /* Array of object pointers */ 79 unsigned int num_alloc; /* Allocated size of the array */ 80 unsigned int num_used; /* Number of array slots used */ 81 } DoneList; 82 83 /* 84 * Function declarations. 85 */ 86 static const char *_getenv_ld(const char *id); 87 static void die(void) __dead2; 88 static void digest_dynamic(Obj_Entry *, int); 89 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 90 static Obj_Entry *dlcheck(void *); 91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 93 static bool donelist_check(DoneList *, const Obj_Entry *); 94 static void errmsg_restore(char *); 95 static char *errmsg_save(void); 96 static void *fill_search_info(const char *, size_t, void *); 97 static char *find_library(const char *, const Obj_Entry *); 98 static const char *gethints(void); 99 static void init_dag(Obj_Entry *); 100 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *); 101 static void init_rtld(caddr_t); 102 static void initlist_add_neededs(Needed_Entry *, Objlist *); 103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 104 static bool is_exported(const Elf_Sym *); 105 static void linkmap_add(Obj_Entry *); 106 static void linkmap_delete(Obj_Entry *); 107 static int load_needed_objects(Obj_Entry *, int); 108 static int load_preload_objects(void); 109 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 110 static Obj_Entry *obj_from_addr(const void *); 111 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 112 static void objlist_call_init(Objlist *, RtldLockState *); 113 static void objlist_clear(Objlist *); 114 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 115 static void objlist_init(Objlist *); 116 static void objlist_push_head(Objlist *, Obj_Entry *); 117 static void objlist_push_tail(Objlist *, Obj_Entry *); 118 static void objlist_remove(Objlist *, Obj_Entry *); 119 static void *path_enumerate(const char *, path_enum_proc, void *); 120 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *); 121 static int rtld_dirname(const char *, char *); 122 static int rtld_dirname_abs(const char *, char *); 123 static void rtld_exit(void); 124 static char *search_library_path(const char *, const char *); 125 static const void **get_program_var_addr(const char *); 126 static void set_program_var(const char *, const void *); 127 static const Elf_Sym *symlook_default(const char *, unsigned long, 128 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int); 129 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *, 130 const Obj_Entry **, const Ver_Entry *, int, DoneList *); 131 static const Elf_Sym *symlook_needed(const char *, unsigned long, 132 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *, 133 int, DoneList *); 134 static void trace_loaded_objects(Obj_Entry *); 135 static void unlink_object(Obj_Entry *); 136 static void unload_object(Obj_Entry *); 137 static void unref_dag(Obj_Entry *); 138 static void ref_dag(Obj_Entry *); 139 static int origin_subst_one(char **, const char *, const char *, 140 const char *, char *); 141 static char *origin_subst(const char *, const char *); 142 static int rtld_verify_versions(const Objlist *); 143 static int rtld_verify_object_versions(Obj_Entry *); 144 static void object_add_name(Obj_Entry *, const char *); 145 static int object_match_name(const Obj_Entry *, const char *); 146 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 147 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 148 struct dl_phdr_info *phdr_info); 149 150 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 151 152 /* 153 * Data declarations. 154 */ 155 static char *error_message; /* Message for dlerror(), or NULL */ 156 struct r_debug r_debug; /* for GDB; */ 157 static bool libmap_disable; /* Disable libmap */ 158 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 159 static bool trust; /* False for setuid and setgid programs */ 160 static bool dangerous_ld_env; /* True if environment variables have been 161 used to affect the libraries loaded */ 162 static const char *ld_bind_now; /* Environment variable for immediate binding */ 163 static const char *ld_debug; /* Environment variable for debugging */ 164 static const char *ld_library_path; /* Environment variable for search path */ 165 static char *ld_preload; /* Environment variable for libraries to 166 load first */ 167 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 168 static const char *ld_tracing; /* Called from ldd(1) to print libs */ 169 /* Optional function call tracing hook */ 170 static const char *ld_utrace; /* Use utrace() to log events. */ 171 static int (*rtld_functrace)(const char *caller_obj, 172 const char *callee_obj, 173 const char *callee_func, 174 void *stack); 175 static Obj_Entry *rtld_functrace_obj; /* Object thereof */ 176 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 177 static Obj_Entry **obj_tail; /* Link field of last object in list */ 178 static Obj_Entry **preload_tail; 179 static Obj_Entry *obj_main; /* The main program shared object */ 180 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 181 static unsigned int obj_count; /* Number of objects in obj_list */ 182 static unsigned int obj_loads; /* Number of objects in obj_list */ 183 184 static int ld_resident; /* Non-zero if resident */ 185 static const char *ld_ary[LD_ARY_CACHE]; 186 static int ld_index; 187 static Objlist initlist; 188 189 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 190 STAILQ_HEAD_INITIALIZER(list_global); 191 static Objlist list_main = /* Objects loaded at program startup */ 192 STAILQ_HEAD_INITIALIZER(list_main); 193 static Objlist list_fini = /* Objects needing fini() calls */ 194 STAILQ_HEAD_INITIALIZER(list_fini); 195 196 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 197 198 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 199 200 extern Elf_Dyn _DYNAMIC; 201 #pragma weak _DYNAMIC 202 #ifndef RTLD_IS_DYNAMIC 203 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 204 #endif 205 206 /* 207 * These are the functions the dynamic linker exports to application 208 * programs. They are the only symbols the dynamic linker is willing 209 * to export from itself. 210 */ 211 static func_ptr_type exports[] = { 212 (func_ptr_type) &_rtld_error, 213 (func_ptr_type) &dlclose, 214 (func_ptr_type) &dlerror, 215 (func_ptr_type) &dlopen, 216 (func_ptr_type) &dlfunc, 217 (func_ptr_type) &dlsym, 218 (func_ptr_type) &dlvsym, 219 (func_ptr_type) &dladdr, 220 (func_ptr_type) &dlinfo, 221 (func_ptr_type) &dl_iterate_phdr, 222 #ifdef __i386__ 223 (func_ptr_type) &___tls_get_addr, 224 #endif 225 (func_ptr_type) &__tls_get_addr, 226 (func_ptr_type) &__tls_get_addr_tcb, 227 (func_ptr_type) &_rtld_allocate_tls, 228 (func_ptr_type) &_rtld_free_tls, 229 (func_ptr_type) &_rtld_call_init, 230 (func_ptr_type) &_rtld_thread_init, 231 (func_ptr_type) &_rtld_addr_phdr, 232 NULL 233 }; 234 235 /* 236 * Global declarations normally provided by crt1. The dynamic linker is 237 * not built with crt1, so we have to provide them ourselves. 238 */ 239 char *__progname; 240 char **environ; 241 242 /* 243 * Globals to control TLS allocation. 244 */ 245 size_t tls_last_offset; /* Static TLS offset of last module */ 246 size_t tls_last_size; /* Static TLS size of last module */ 247 size_t tls_static_space; /* Static TLS space allocated */ 248 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 249 int tls_max_index = 1; /* Largest module index allocated */ 250 251 /* 252 * Fill in a DoneList with an allocation large enough to hold all of 253 * the currently-loaded objects. Keep this as a macro since it calls 254 * alloca and we want that to occur within the scope of the caller. 255 */ 256 #define donelist_init(dlp) \ 257 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 258 assert((dlp)->objs != NULL), \ 259 (dlp)->num_alloc = obj_count, \ 260 (dlp)->num_used = 0) 261 262 #define UTRACE_DLOPEN_START 1 263 #define UTRACE_DLOPEN_STOP 2 264 #define UTRACE_DLCLOSE_START 3 265 #define UTRACE_DLCLOSE_STOP 4 266 #define UTRACE_LOAD_OBJECT 5 267 #define UTRACE_UNLOAD_OBJECT 6 268 #define UTRACE_ADD_RUNDEP 7 269 #define UTRACE_PRELOAD_FINISHED 8 270 #define UTRACE_INIT_CALL 9 271 #define UTRACE_FINI_CALL 10 272 273 struct utrace_rtld { 274 char sig[4]; /* 'RTLD' */ 275 int event; 276 void *handle; 277 void *mapbase; /* Used for 'parent' and 'init/fini' */ 278 size_t mapsize; 279 int refcnt; /* Used for 'mode' */ 280 char name[MAXPATHLEN]; 281 }; 282 283 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 284 if (ld_utrace != NULL) \ 285 ld_utrace_log(e, h, mb, ms, r, n); \ 286 } while (0) 287 288 static void 289 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 290 int refcnt, const char *name) 291 { 292 struct utrace_rtld ut; 293 294 ut.sig[0] = 'R'; 295 ut.sig[1] = 'T'; 296 ut.sig[2] = 'L'; 297 ut.sig[3] = 'D'; 298 ut.event = event; 299 ut.handle = handle; 300 ut.mapbase = mapbase; 301 ut.mapsize = mapsize; 302 ut.refcnt = refcnt; 303 bzero(ut.name, sizeof(ut.name)); 304 if (name) 305 strlcpy(ut.name, name, sizeof(ut.name)); 306 utrace(&ut, sizeof(ut)); 307 } 308 309 /* 310 * Main entry point for dynamic linking. The first argument is the 311 * stack pointer. The stack is expected to be laid out as described 312 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 313 * Specifically, the stack pointer points to a word containing 314 * ARGC. Following that in the stack is a null-terminated sequence 315 * of pointers to argument strings. Then comes a null-terminated 316 * sequence of pointers to environment strings. Finally, there is a 317 * sequence of "auxiliary vector" entries. 318 * 319 * The second argument points to a place to store the dynamic linker's 320 * exit procedure pointer and the third to a place to store the main 321 * program's object. 322 * 323 * The return value is the main program's entry point. 324 */ 325 func_ptr_type 326 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 327 { 328 Elf_Auxinfo *aux_info[AT_COUNT]; 329 int i; 330 int argc; 331 char **argv; 332 char **env; 333 Elf_Auxinfo *aux; 334 Elf_Auxinfo *auxp; 335 const char *argv0; 336 Objlist_Entry *entry; 337 Obj_Entry *obj; 338 339 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 340 Obj_Entry **preload_tail; 341 Objlist initlist; 342 from global to here. It will break the DRAWF2 unwind scheme. 343 The system compilers were unaffected, but not gcc 4.6 344 */ 345 346 /* 347 * On entry, the dynamic linker itself has not been relocated yet. 348 * Be very careful not to reference any global data until after 349 * init_rtld has returned. It is OK to reference file-scope statics 350 * and string constants, and to call static and global functions. 351 */ 352 353 /* Find the auxiliary vector on the stack. */ 354 argc = *sp++; 355 argv = (char **) sp; 356 sp += argc + 1; /* Skip over arguments and NULL terminator */ 357 env = (char **) sp; 358 359 /* 360 * If we aren't already resident we have to dig out some more info. 361 * Note that auxinfo does not exist when we are resident. 362 * 363 * I'm not sure about the ld_resident check. It seems to read zero 364 * prior to relocation, which is what we want. When running from a 365 * resident copy everything will be relocated so we are definitely 366 * good there. 367 */ 368 if (ld_resident == 0) { 369 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 370 ; 371 aux = (Elf_Auxinfo *) sp; 372 373 /* Digest the auxiliary vector. */ 374 for (i = 0; i < AT_COUNT; i++) 375 aux_info[i] = NULL; 376 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 377 if (auxp->a_type < AT_COUNT) 378 aux_info[auxp->a_type] = auxp; 379 } 380 381 /* Initialize and relocate ourselves. */ 382 assert(aux_info[AT_BASE] != NULL); 383 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 384 } 385 386 ld_index = 0; /* don't use old env cache in case we are resident */ 387 __progname = obj_rtld.path; 388 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 389 environ = env; 390 391 trust = !issetugid(); 392 393 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 394 /* 395 * If the process is tainted, then we un-set the dangerous environment 396 * variables. The process will be marked as tainted until setuid(2) 397 * is called. If any child process calls setuid(2) we do not want any 398 * future processes to honor the potentially un-safe variables. 399 */ 400 if (!trust) { 401 if ( unsetenv("LD_DEBUG") 402 || unsetenv("LD_PRELOAD") 403 || unsetenv("LD_LIBRARY_PATH") 404 || unsetenv("LD_ELF_HINTS_PATH") 405 || unsetenv("LD_LIBMAP") 406 || unsetenv("LD_LIBMAP_DISABLE") 407 ) { 408 _rtld_error("environment corrupt; aborting"); 409 die(); 410 } 411 } 412 ld_debug = _getenv_ld("LD_DEBUG"); 413 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 414 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 415 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 416 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 417 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 418 dangerous_ld_env = (ld_library_path != NULL) 419 || (ld_preload != NULL) 420 || (ld_elf_hints_path != NULL) 421 || (libmap_override != NULL) 422 || libmap_disable 423 ; 424 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 425 ld_utrace = _getenv_ld("LD_UTRACE"); 426 427 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 428 ld_elf_hints_path = _PATH_ELF_HINTS; 429 430 if (ld_debug != NULL && *ld_debug != '\0') 431 debug = 1; 432 dbg("%s is initialized, base address = %p", __progname, 433 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 434 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 435 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 436 437 dbg("initializing thread locks"); 438 lockdflt_init(); 439 440 /* 441 * If we are resident we can skip work that we have already done. 442 * Note that the stack is reset and there is no Elf_Auxinfo 443 * when running from a resident image, and the static globals setup 444 * between here and resident_skip will have already been setup. 445 */ 446 if (ld_resident) 447 goto resident_skip1; 448 449 /* 450 * Load the main program, or process its program header if it is 451 * already loaded. 452 */ 453 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 454 int fd = aux_info[AT_EXECFD]->a_un.a_val; 455 dbg("loading main program"); 456 obj_main = map_object(fd, argv0, NULL); 457 close(fd); 458 if (obj_main == NULL) 459 die(); 460 } else { /* Main program already loaded. */ 461 const Elf_Phdr *phdr; 462 int phnum; 463 caddr_t entry; 464 465 dbg("processing main program's program header"); 466 assert(aux_info[AT_PHDR] != NULL); 467 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 468 assert(aux_info[AT_PHNUM] != NULL); 469 phnum = aux_info[AT_PHNUM]->a_un.a_val; 470 assert(aux_info[AT_PHENT] != NULL); 471 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 472 assert(aux_info[AT_ENTRY] != NULL); 473 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 474 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 475 die(); 476 } 477 478 char buf[MAXPATHLEN]; 479 if (aux_info[AT_EXECPATH] != 0) { 480 char *kexecpath; 481 482 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 483 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 484 if (kexecpath[0] == '/') 485 obj_main->path = kexecpath; 486 else if (getcwd(buf, sizeof(buf)) == NULL || 487 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 488 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 489 obj_main->path = xstrdup(argv0); 490 else 491 obj_main->path = xstrdup(buf); 492 } else { 493 char resolved[MAXPATHLEN]; 494 dbg("No AT_EXECPATH"); 495 if (argv0[0] == '/') { 496 if (realpath(argv0, resolved) != NULL) 497 obj_main->path = xstrdup(resolved); 498 else 499 obj_main->path = xstrdup(argv0); 500 } else { 501 if (getcwd(buf, sizeof(buf)) != NULL 502 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 503 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 504 && access(buf, R_OK) == 0 505 && realpath(buf, resolved) != NULL) 506 obj_main->path = xstrdup(resolved); 507 else 508 obj_main->path = xstrdup(argv0); 509 } 510 } 511 dbg("obj_main path %s", obj_main->path); 512 obj_main->mainprog = true; 513 514 /* 515 * Get the actual dynamic linker pathname from the executable if 516 * possible. (It should always be possible.) That ensures that 517 * gdb will find the right dynamic linker even if a non-standard 518 * one is being used. 519 */ 520 if (obj_main->interp != NULL && 521 strcmp(obj_main->interp, obj_rtld.path) != 0) { 522 free(obj_rtld.path); 523 obj_rtld.path = xstrdup(obj_main->interp); 524 __progname = obj_rtld.path; 525 } 526 527 digest_dynamic(obj_main, 0); 528 529 linkmap_add(obj_main); 530 linkmap_add(&obj_rtld); 531 532 /* Link the main program into the list of objects. */ 533 *obj_tail = obj_main; 534 obj_tail = &obj_main->next; 535 obj_count++; 536 obj_loads++; 537 /* Make sure we don't call the main program's init and fini functions. */ 538 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 539 540 /* Initialize a fake symbol for resolving undefined weak references. */ 541 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 542 sym_zero.st_shndx = SHN_UNDEF; 543 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 544 545 if (!libmap_disable) 546 libmap_disable = (bool)lm_init(libmap_override); 547 548 dbg("loading LD_PRELOAD libraries"); 549 if (load_preload_objects() == -1) 550 die(); 551 preload_tail = obj_tail; 552 553 dbg("loading needed objects"); 554 if (load_needed_objects(obj_main, 0) == -1) 555 die(); 556 557 /* Make a list of all objects loaded at startup. */ 558 for (obj = obj_list; obj != NULL; obj = obj->next) { 559 objlist_push_tail(&list_main, obj); 560 obj->refcount++; 561 } 562 563 dbg("checking for required versions"); 564 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 565 die(); 566 567 resident_skip1: 568 569 if (ld_tracing) { /* We're done */ 570 trace_loaded_objects(obj_main); 571 exit(0); 572 } 573 574 if (ld_resident) /* XXX clean this up! */ 575 goto resident_skip2; 576 577 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 578 dump_relocations(obj_main); 579 exit (0); 580 } 581 582 /* setup TLS for main thread */ 583 dbg("initializing initial thread local storage"); 584 STAILQ_FOREACH(entry, &list_main, link) { 585 /* 586 * Allocate all the initial objects out of the static TLS 587 * block even if they didn't ask for it. 588 */ 589 allocate_tls_offset(entry->obj); 590 } 591 592 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 593 594 /* 595 * Do not try to allocate the TLS here, let libc do it itself. 596 * (crt1 for the program will call _init_tls()) 597 */ 598 599 if (relocate_objects(obj_main, 600 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1) 601 die(); 602 603 dbg("doing copy relocations"); 604 if (do_copy_relocations(obj_main) == -1) 605 die(); 606 607 resident_skip2: 608 609 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 610 if (exec_sys_unregister(-1) < 0) { 611 dbg("exec_sys_unregister failed %d\n", errno); 612 exit(errno); 613 } 614 dbg("exec_sys_unregister success\n"); 615 exit(0); 616 } 617 618 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 619 dump_relocations(obj_main); 620 exit (0); 621 } 622 623 dbg("initializing key program variables"); 624 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 625 set_program_var("environ", env); 626 627 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 628 extern void resident_start(void); 629 ld_resident = 1; 630 if (exec_sys_register(resident_start) < 0) { 631 dbg("exec_sys_register failed %d\n", errno); 632 exit(errno); 633 } 634 dbg("exec_sys_register success\n"); 635 exit(0); 636 } 637 638 /* Make a list of init functions to call. */ 639 objlist_init(&initlist); 640 initlist_add_objects(obj_list, preload_tail, &initlist); 641 642 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 643 644 /* 645 * Do NOT call the initlist here, give libc a chance to set up 646 * the initial TLS segment. crt1 will then call _rtld_call_init(). 647 */ 648 649 dbg("transferring control to program entry point = %p", obj_main->entry); 650 651 /* Return the exit procedure and the program entry point. */ 652 *exit_proc = rtld_exit; 653 *objp = obj_main; 654 return (func_ptr_type) obj_main->entry; 655 } 656 657 /* 658 * Call the initialization list for dynamically loaded libraries. 659 * (called from crt1.c). 660 */ 661 void 662 _rtld_call_init(void) 663 { 664 RtldLockState lockstate; 665 666 wlock_acquire(rtld_bind_lock, &lockstate); 667 objlist_call_init(&initlist, &lockstate); 668 objlist_clear(&initlist); 669 lock_release(rtld_bind_lock, &lockstate); 670 } 671 672 Elf_Addr 673 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 674 { 675 const Elf_Rel *rel; 676 const Elf_Sym *def; 677 const Obj_Entry *defobj; 678 Elf_Addr *where; 679 Elf_Addr target; 680 RtldLockState lockstate; 681 int do_reloc = 1; 682 683 rlock_acquire(rtld_bind_lock, &lockstate); 684 if (sigsetjmp(lockstate.env, 0) != 0) 685 lock_upgrade(rtld_bind_lock, &lockstate); 686 if (obj->pltrel) 687 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 688 else 689 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 690 691 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 692 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); 693 if (def == NULL) 694 die(); 695 696 target = (Elf_Addr)(defobj->relocbase + def->st_value); 697 698 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 699 defobj->strtab + def->st_name, basename(obj->path), 700 (void *)target, basename(defobj->path)); 701 702 /* 703 * If we have a function call tracing hook, and the 704 * hook would like to keep tracing this one function, 705 * prevent the relocation so we will wind up here 706 * the next time again. 707 * 708 * We don't want to functrace calls from the functracer 709 * to avoid recursive loops. 710 */ 711 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 712 if (rtld_functrace(obj->path, 713 defobj->path, 714 defobj->strtab + def->st_name, 715 stack)) 716 do_reloc = 0; 717 } 718 719 if (do_reloc) 720 target = reloc_jmpslot(where, target, defobj, obj, rel); 721 lock_release(rtld_bind_lock, &lockstate); 722 return target; 723 } 724 725 /* 726 * Error reporting function. Use it like printf. If formats the message 727 * into a buffer, and sets things up so that the next call to dlerror() 728 * will return the message. 729 */ 730 void 731 _rtld_error(const char *fmt, ...) 732 { 733 static char buf[512]; 734 va_list ap; 735 736 va_start(ap, fmt); 737 vsnprintf(buf, sizeof buf, fmt, ap); 738 error_message = buf; 739 va_end(ap); 740 } 741 742 /* 743 * Return a dynamically-allocated copy of the current error message, if any. 744 */ 745 static char * 746 errmsg_save(void) 747 { 748 return error_message == NULL ? NULL : xstrdup(error_message); 749 } 750 751 /* 752 * Restore the current error message from a copy which was previously saved 753 * by errmsg_save(). The copy is freed. 754 */ 755 static void 756 errmsg_restore(char *saved_msg) 757 { 758 if (saved_msg == NULL) 759 error_message = NULL; 760 else { 761 _rtld_error("%s", saved_msg); 762 free(saved_msg); 763 } 764 } 765 766 const char * 767 basename(const char *name) 768 { 769 const char *p = strrchr(name, '/'); 770 return p != NULL ? p + 1 : name; 771 } 772 773 static struct utsname uts; 774 775 static int 776 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 777 char *may_free) 778 { 779 const char *p, *p1; 780 char *res1; 781 int subst_len; 782 int kw_len; 783 784 res1 = *res = NULL; 785 p = real; 786 subst_len = kw_len = 0; 787 for (;;) { 788 p1 = strstr(p, kw); 789 if (p1 != NULL) { 790 if (subst_len == 0) { 791 subst_len = strlen(subst); 792 kw_len = strlen(kw); 793 } 794 if (*res == NULL) { 795 *res = xmalloc(PATH_MAX); 796 res1 = *res; 797 } 798 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 799 _rtld_error("Substitution of %s in %s cannot be performed", 800 kw, real); 801 if (may_free != NULL) 802 free(may_free); 803 free(res); 804 return (false); 805 } 806 memcpy(res1, p, p1 - p); 807 res1 += p1 - p; 808 memcpy(res1, subst, subst_len); 809 res1 += subst_len; 810 p = p1 + kw_len; 811 } else { 812 if (*res == NULL) { 813 if (may_free != NULL) 814 *res = may_free; 815 else 816 *res = xstrdup(real); 817 return (true); 818 } 819 *res1 = '\0'; 820 if (may_free != NULL) 821 free(may_free); 822 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 823 free(res); 824 return (false); 825 } 826 return (true); 827 } 828 } 829 } 830 831 static char * 832 origin_subst(const char *real, const char *origin_path) 833 { 834 char *res1, *res2, *res3, *res4; 835 836 if (uts.sysname[0] == '\0') { 837 if (uname(&uts) != 0) { 838 _rtld_error("utsname failed: %d", errno); 839 return (NULL); 840 } 841 } 842 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 843 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 844 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 845 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 846 return (NULL); 847 return (res4); 848 } 849 850 static void 851 die(void) 852 { 853 const char *msg = dlerror(); 854 855 if (msg == NULL) 856 msg = "Fatal error"; 857 errx(1, "%s", msg); 858 } 859 860 /* 861 * Process a shared object's DYNAMIC section, and save the important 862 * information in its Obj_Entry structure. 863 */ 864 static void 865 digest_dynamic(Obj_Entry *obj, int early) 866 { 867 const Elf_Dyn *dynp; 868 Needed_Entry **needed_tail = &obj->needed; 869 const Elf_Dyn *dyn_rpath = NULL; 870 const Elf_Dyn *dyn_soname = NULL; 871 int plttype = DT_REL; 872 873 obj->bind_now = false; 874 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 875 switch (dynp->d_tag) { 876 877 case DT_REL: 878 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 879 break; 880 881 case DT_RELSZ: 882 obj->relsize = dynp->d_un.d_val; 883 break; 884 885 case DT_RELENT: 886 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 887 break; 888 889 case DT_JMPREL: 890 obj->pltrel = (const Elf_Rel *) 891 (obj->relocbase + dynp->d_un.d_ptr); 892 break; 893 894 case DT_PLTRELSZ: 895 obj->pltrelsize = dynp->d_un.d_val; 896 break; 897 898 case DT_RELA: 899 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 900 break; 901 902 case DT_RELASZ: 903 obj->relasize = dynp->d_un.d_val; 904 break; 905 906 case DT_RELAENT: 907 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 908 break; 909 910 case DT_PLTREL: 911 plttype = dynp->d_un.d_val; 912 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 913 break; 914 915 case DT_SYMTAB: 916 obj->symtab = (const Elf_Sym *) 917 (obj->relocbase + dynp->d_un.d_ptr); 918 break; 919 920 case DT_SYMENT: 921 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 922 break; 923 924 case DT_STRTAB: 925 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 926 break; 927 928 case DT_STRSZ: 929 obj->strsize = dynp->d_un.d_val; 930 break; 931 932 case DT_VERNEED: 933 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 934 dynp->d_un.d_val); 935 break; 936 937 case DT_VERNEEDNUM: 938 obj->verneednum = dynp->d_un.d_val; 939 break; 940 941 case DT_VERDEF: 942 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 943 dynp->d_un.d_val); 944 break; 945 946 case DT_VERDEFNUM: 947 obj->verdefnum = dynp->d_un.d_val; 948 break; 949 950 case DT_VERSYM: 951 obj->versyms = (const Elf_Versym *)(obj->relocbase + 952 dynp->d_un.d_val); 953 break; 954 955 case DT_HASH: 956 { 957 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 958 (obj->relocbase + dynp->d_un.d_ptr); 959 obj->nbuckets = hashtab[0]; 960 obj->nchains = hashtab[1]; 961 obj->buckets = hashtab + 2; 962 obj->chains = obj->buckets + obj->nbuckets; 963 } 964 break; 965 966 case DT_NEEDED: 967 if (!obj->rtld) { 968 Needed_Entry *nep = NEW(Needed_Entry); 969 nep->name = dynp->d_un.d_val; 970 nep->obj = NULL; 971 nep->next = NULL; 972 973 *needed_tail = nep; 974 needed_tail = &nep->next; 975 } 976 break; 977 978 case DT_PLTGOT: 979 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 980 break; 981 982 case DT_TEXTREL: 983 obj->textrel = true; 984 break; 985 986 case DT_SYMBOLIC: 987 obj->symbolic = true; 988 break; 989 990 case DT_RPATH: 991 case DT_RUNPATH: /* XXX: process separately */ 992 /* 993 * We have to wait until later to process this, because we 994 * might not have gotten the address of the string table yet. 995 */ 996 dyn_rpath = dynp; 997 break; 998 999 case DT_SONAME: 1000 dyn_soname = dynp; 1001 break; 1002 1003 case DT_INIT: 1004 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1005 break; 1006 1007 case DT_FINI: 1008 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1009 break; 1010 1011 case DT_DEBUG: 1012 /* XXX - not implemented yet */ 1013 if (!early) 1014 dbg("Filling in DT_DEBUG entry"); 1015 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1016 break; 1017 1018 case DT_FLAGS: 1019 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1020 obj->z_origin = true; 1021 if (dynp->d_un.d_val & DF_SYMBOLIC) 1022 obj->symbolic = true; 1023 if (dynp->d_un.d_val & DF_TEXTREL) 1024 obj->textrel = true; 1025 if (dynp->d_un.d_val & DF_BIND_NOW) 1026 obj->bind_now = true; 1027 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1028 ;*/ 1029 break; 1030 1031 case DT_FLAGS_1: 1032 if (dynp->d_un.d_val & DF_1_NOOPEN) 1033 obj->z_noopen = true; 1034 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1035 obj->z_origin = true; 1036 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1037 XXX ;*/ 1038 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1039 obj->bind_now = true; 1040 if (dynp->d_un.d_val & DF_1_NODELETE) 1041 obj->z_nodelete = true; 1042 break; 1043 1044 default: 1045 if (!early) { 1046 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1047 (long)dynp->d_tag); 1048 } 1049 break; 1050 } 1051 } 1052 1053 obj->traced = false; 1054 1055 if (plttype == DT_RELA) { 1056 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1057 obj->pltrel = NULL; 1058 obj->pltrelasize = obj->pltrelsize; 1059 obj->pltrelsize = 0; 1060 } 1061 1062 if (obj->z_origin && obj->origin_path == NULL) { 1063 obj->origin_path = xmalloc(PATH_MAX); 1064 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1065 die(); 1066 } 1067 1068 if (dyn_rpath != NULL) { 1069 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1070 if (obj->z_origin) 1071 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1072 } 1073 1074 if (dyn_soname != NULL) 1075 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1076 } 1077 1078 /* 1079 * Process a shared object's program header. This is used only for the 1080 * main program, when the kernel has already loaded the main program 1081 * into memory before calling the dynamic linker. It creates and 1082 * returns an Obj_Entry structure. 1083 */ 1084 static Obj_Entry * 1085 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1086 { 1087 Obj_Entry *obj; 1088 const Elf_Phdr *phlimit = phdr + phnum; 1089 const Elf_Phdr *ph; 1090 int nsegs = 0; 1091 1092 obj = obj_new(); 1093 for (ph = phdr; ph < phlimit; ph++) { 1094 if (ph->p_type != PT_PHDR) 1095 continue; 1096 1097 obj->phdr = phdr; 1098 obj->phsize = ph->p_memsz; 1099 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1100 break; 1101 } 1102 1103 for (ph = phdr; ph < phlimit; ph++) { 1104 switch (ph->p_type) { 1105 1106 case PT_INTERP: 1107 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1108 break; 1109 1110 case PT_LOAD: 1111 if (nsegs == 0) { /* First load segment */ 1112 obj->vaddrbase = trunc_page(ph->p_vaddr); 1113 obj->mapbase = obj->vaddrbase + obj->relocbase; 1114 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1115 obj->vaddrbase; 1116 } else { /* Last load segment */ 1117 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1118 obj->vaddrbase; 1119 } 1120 nsegs++; 1121 break; 1122 1123 case PT_DYNAMIC: 1124 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1125 break; 1126 1127 case PT_TLS: 1128 obj->tlsindex = 1; 1129 obj->tlssize = ph->p_memsz; 1130 obj->tlsalign = ph->p_align; 1131 obj->tlsinitsize = ph->p_filesz; 1132 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1133 break; 1134 1135 case PT_GNU_RELRO: 1136 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1137 obj->relro_size = round_page(ph->p_memsz); 1138 break; 1139 } 1140 } 1141 if (nsegs < 1) { 1142 _rtld_error("%s: too few PT_LOAD segments", path); 1143 return NULL; 1144 } 1145 1146 obj->entry = entry; 1147 return obj; 1148 } 1149 1150 static Obj_Entry * 1151 dlcheck(void *handle) 1152 { 1153 Obj_Entry *obj; 1154 1155 for (obj = obj_list; obj != NULL; obj = obj->next) 1156 if (obj == (Obj_Entry *) handle) 1157 break; 1158 1159 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1160 _rtld_error("Invalid shared object handle %p", handle); 1161 return NULL; 1162 } 1163 return obj; 1164 } 1165 1166 /* 1167 * If the given object is already in the donelist, return true. Otherwise 1168 * add the object to the list and return false. 1169 */ 1170 static bool 1171 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1172 { 1173 unsigned int i; 1174 1175 for (i = 0; i < dlp->num_used; i++) 1176 if (dlp->objs[i] == obj) 1177 return true; 1178 /* 1179 * Our donelist allocation should always be sufficient. But if 1180 * our threads locking isn't working properly, more shared objects 1181 * could have been loaded since we allocated the list. That should 1182 * never happen, but we'll handle it properly just in case it does. 1183 */ 1184 if (dlp->num_used < dlp->num_alloc) 1185 dlp->objs[dlp->num_used++] = obj; 1186 return false; 1187 } 1188 1189 /* 1190 * Hash function for symbol table lookup. Don't even think about changing 1191 * this. It is specified by the System V ABI. 1192 */ 1193 unsigned long 1194 elf_hash(const char *name) 1195 { 1196 const unsigned char *p = (const unsigned char *) name; 1197 unsigned long h = 0; 1198 unsigned long g; 1199 1200 while (*p != '\0') { 1201 h = (h << 4) + *p++; 1202 if ((g = h & 0xf0000000) != 0) 1203 h ^= g >> 24; 1204 h &= ~g; 1205 } 1206 return h; 1207 } 1208 1209 /* 1210 * Find the library with the given name, and return its full pathname. 1211 * The returned string is dynamically allocated. Generates an error 1212 * message and returns NULL if the library cannot be found. 1213 * 1214 * If the second argument is non-NULL, then it refers to an already- 1215 * loaded shared object, whose library search path will be searched. 1216 * 1217 * The search order is: 1218 * LD_LIBRARY_PATH 1219 * rpath in the referencing file 1220 * ldconfig hints 1221 * /usr/lib 1222 */ 1223 static char * 1224 find_library(const char *xname, const Obj_Entry *refobj) 1225 { 1226 char *pathname; 1227 char *name; 1228 1229 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1230 if (xname[0] != '/' && !trust) { 1231 _rtld_error("Absolute pathname required for shared object \"%s\"", 1232 xname); 1233 return NULL; 1234 } 1235 if (refobj != NULL && refobj->z_origin) 1236 return origin_subst(xname, refobj->origin_path); 1237 else 1238 return xstrdup(xname); 1239 } 1240 1241 if (libmap_disable || (refobj == NULL) || 1242 (name = lm_find(refobj->path, xname)) == NULL) 1243 name = (char *)xname; 1244 1245 dbg(" Searching for \"%s\"", name); 1246 1247 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1248 (refobj != NULL && 1249 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1250 (pathname = search_library_path(name, gethints())) != NULL || 1251 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1252 return pathname; 1253 1254 if(refobj != NULL && refobj->path != NULL) { 1255 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1256 name, basename(refobj->path)); 1257 } else { 1258 _rtld_error("Shared object \"%s\" not found", name); 1259 } 1260 return NULL; 1261 } 1262 1263 /* 1264 * Given a symbol number in a referencing object, find the corresponding 1265 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1266 * no definition was found. Returns a pointer to the Obj_Entry of the 1267 * defining object via the reference parameter DEFOBJ_OUT. 1268 */ 1269 const Elf_Sym * 1270 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1271 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1272 { 1273 const Elf_Sym *ref; 1274 const Elf_Sym *def; 1275 const Obj_Entry *defobj; 1276 const Ver_Entry *ventry; 1277 const char *name; 1278 unsigned long hash; 1279 1280 /* 1281 * If we have already found this symbol, get the information from 1282 * the cache. 1283 */ 1284 if (symnum >= refobj->nchains) 1285 return NULL; /* Bad object */ 1286 if (cache != NULL && cache[symnum].sym != NULL) { 1287 *defobj_out = cache[symnum].obj; 1288 return cache[symnum].sym; 1289 } 1290 1291 ref = refobj->symtab + symnum; 1292 name = refobj->strtab + ref->st_name; 1293 defobj = NULL; 1294 1295 /* 1296 * We don't have to do a full scale lookup if the symbol is local. 1297 * We know it will bind to the instance in this load module; to 1298 * which we already have a pointer (ie ref). By not doing a lookup, 1299 * we not only improve performance, but it also avoids unresolvable 1300 * symbols when local symbols are not in the hash table. 1301 * 1302 * This might occur for TLS module relocations, which simply use 1303 * symbol 0. 1304 */ 1305 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1306 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1307 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1308 symnum); 1309 } 1310 ventry = fetch_ventry(refobj, symnum); 1311 hash = elf_hash(name); 1312 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1313 } else { 1314 def = ref; 1315 defobj = refobj; 1316 } 1317 1318 /* 1319 * If we found no definition and the reference is weak, treat the 1320 * symbol as having the value zero. 1321 */ 1322 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1323 def = &sym_zero; 1324 defobj = obj_main; 1325 } 1326 1327 if (def != NULL) { 1328 *defobj_out = defobj; 1329 /* Record the information in the cache to avoid subsequent lookups. */ 1330 if (cache != NULL) { 1331 cache[symnum].sym = def; 1332 cache[symnum].obj = defobj; 1333 } 1334 } else { 1335 if (refobj != &obj_rtld) 1336 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1337 } 1338 return def; 1339 } 1340 1341 /* 1342 * Return the search path from the ldconfig hints file, reading it if 1343 * necessary. Returns NULL if there are problems with the hints file, 1344 * or if the search path there is empty. 1345 */ 1346 static const char * 1347 gethints(void) 1348 { 1349 static char *hints; 1350 1351 if (hints == NULL) { 1352 int fd; 1353 struct elfhints_hdr hdr; 1354 char *p; 1355 1356 /* Keep from trying again in case the hints file is bad. */ 1357 hints = ""; 1358 1359 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1360 return NULL; 1361 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1362 hdr.magic != ELFHINTS_MAGIC || 1363 hdr.version != 1) { 1364 close(fd); 1365 return NULL; 1366 } 1367 p = xmalloc(hdr.dirlistlen + 1); 1368 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1369 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1370 free(p); 1371 close(fd); 1372 return NULL; 1373 } 1374 hints = p; 1375 close(fd); 1376 } 1377 return hints[0] != '\0' ? hints : NULL; 1378 } 1379 1380 static void 1381 init_dag(Obj_Entry *root) 1382 { 1383 DoneList donelist; 1384 1385 if (root->dag_inited) 1386 return; 1387 donelist_init(&donelist); 1388 init_dag1(root, root, &donelist); 1389 } 1390 1391 static void 1392 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1393 { 1394 const Needed_Entry *needed; 1395 1396 if (donelist_check(dlp, obj)) 1397 return; 1398 1399 objlist_push_tail(&obj->dldags, root); 1400 objlist_push_tail(&root->dagmembers, obj); 1401 for (needed = obj->needed; needed != NULL; needed = needed->next) 1402 if (needed->obj != NULL) 1403 init_dag1(root, needed->obj, dlp); 1404 root->dag_inited = true; 1405 } 1406 1407 /* 1408 * Initialize the dynamic linker. The argument is the address at which 1409 * the dynamic linker has been mapped into memory. The primary task of 1410 * this function is to relocate the dynamic linker. 1411 */ 1412 static void 1413 init_rtld(caddr_t mapbase) 1414 { 1415 Obj_Entry objtmp; /* Temporary rtld object */ 1416 1417 /* 1418 * Conjure up an Obj_Entry structure for the dynamic linker. 1419 * 1420 * The "path" member can't be initialized yet because string constants 1421 * cannot yet be accessed. Below we will set it correctly. 1422 */ 1423 memset(&objtmp, 0, sizeof(objtmp)); 1424 objtmp.path = NULL; 1425 objtmp.rtld = true; 1426 objtmp.mapbase = mapbase; 1427 #ifdef PIC 1428 objtmp.relocbase = mapbase; 1429 #endif 1430 if (RTLD_IS_DYNAMIC()) { 1431 objtmp.dynamic = rtld_dynamic(&objtmp); 1432 digest_dynamic(&objtmp, 1); 1433 assert(objtmp.needed == NULL); 1434 assert(!objtmp.textrel); 1435 1436 /* 1437 * Temporarily put the dynamic linker entry into the object list, so 1438 * that symbols can be found. 1439 */ 1440 1441 relocate_objects(&objtmp, true, &objtmp); 1442 } 1443 1444 /* Initialize the object list. */ 1445 obj_tail = &obj_list; 1446 1447 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1448 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1449 1450 /* Replace the path with a dynamically allocated copy. */ 1451 obj_rtld.path = xstrdup(PATH_RTLD); 1452 1453 r_debug.r_brk = r_debug_state; 1454 r_debug.r_state = RT_CONSISTENT; 1455 } 1456 1457 /* 1458 * Add the init functions from a needed object list (and its recursive 1459 * needed objects) to "list". This is not used directly; it is a helper 1460 * function for initlist_add_objects(). The write lock must be held 1461 * when this function is called. 1462 */ 1463 static void 1464 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1465 { 1466 /* Recursively process the successor needed objects. */ 1467 if (needed->next != NULL) 1468 initlist_add_neededs(needed->next, list); 1469 1470 /* Process the current needed object. */ 1471 if (needed->obj != NULL) 1472 initlist_add_objects(needed->obj, &needed->obj->next, list); 1473 } 1474 1475 /* 1476 * Scan all of the DAGs rooted in the range of objects from "obj" to 1477 * "tail" and add their init functions to "list". This recurses over 1478 * the DAGs and ensure the proper init ordering such that each object's 1479 * needed libraries are initialized before the object itself. At the 1480 * same time, this function adds the objects to the global finalization 1481 * list "list_fini" in the opposite order. The write lock must be 1482 * held when this function is called. 1483 */ 1484 static void 1485 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1486 { 1487 if (obj->init_scanned || obj->init_done) 1488 return; 1489 obj->init_scanned = true; 1490 1491 /* Recursively process the successor objects. */ 1492 if (&obj->next != tail) 1493 initlist_add_objects(obj->next, tail, list); 1494 1495 /* Recursively process the needed objects. */ 1496 if (obj->needed != NULL) 1497 initlist_add_neededs(obj->needed, list); 1498 1499 /* Add the object to the init list. */ 1500 if (obj->init != (Elf_Addr)NULL) 1501 objlist_push_tail(list, obj); 1502 1503 /* Add the object to the global fini list in the reverse order. */ 1504 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1505 objlist_push_head(&list_fini, obj); 1506 obj->on_fini_list = true; 1507 } 1508 } 1509 1510 #ifndef FPTR_TARGET 1511 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1512 #endif 1513 1514 static bool 1515 is_exported(const Elf_Sym *def) 1516 { 1517 Elf_Addr value; 1518 const func_ptr_type *p; 1519 1520 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1521 for (p = exports; *p != NULL; p++) 1522 if (FPTR_TARGET(*p) == value) 1523 return true; 1524 return false; 1525 } 1526 1527 /* 1528 * Given a shared object, traverse its list of needed objects, and load 1529 * each of them. Returns 0 on success. Generates an error message and 1530 * returns -1 on failure. 1531 */ 1532 static int 1533 load_needed_objects(Obj_Entry *first, int flags) 1534 { 1535 Obj_Entry *obj, *obj1; 1536 1537 for (obj = first; obj != NULL; obj = obj->next) { 1538 Needed_Entry *needed; 1539 1540 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1541 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1542 flags & ~RTLD_LO_NOLOAD); 1543 if (obj1 == NULL && !ld_tracing) 1544 return -1; 1545 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1546 dbg("obj %s nodelete", obj1->path); 1547 init_dag(obj1); 1548 ref_dag(obj1); 1549 obj1->ref_nodel = true; 1550 } 1551 } 1552 } 1553 return (0); 1554 } 1555 1556 #define RTLD_FUNCTRACE "_rtld_functrace" 1557 1558 static int 1559 load_preload_objects(void) 1560 { 1561 char *p = ld_preload; 1562 static const char delim[] = " \t:;"; 1563 1564 if (p == NULL) 1565 return 0; 1566 1567 p += strspn(p, delim); 1568 while (*p != '\0') { 1569 size_t len = strcspn(p, delim); 1570 char savech; 1571 Obj_Entry *obj; 1572 const Elf_Sym *sym; 1573 1574 savech = p[len]; 1575 p[len] = '\0'; 1576 obj = load_object(p, NULL, 0); 1577 if (obj == NULL) 1578 return -1; /* XXX - cleanup */ 1579 p[len] = savech; 1580 p += len; 1581 p += strspn(p, delim); 1582 1583 /* Check for the magic tracing function */ 1584 sym = symlook_obj(RTLD_FUNCTRACE, elf_hash(RTLD_FUNCTRACE), obj, NULL, 1); 1585 if (sym != NULL) { 1586 rtld_functrace = (void *)(obj->relocbase + sym->st_value); 1587 rtld_functrace_obj = obj; 1588 } 1589 } 1590 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1591 return 0; 1592 } 1593 1594 /* 1595 * Load a shared object into memory, if it is not already loaded. 1596 * 1597 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1598 * on failure. 1599 */ 1600 static Obj_Entry * 1601 load_object(const char *name, const Obj_Entry *refobj, int flags) 1602 { 1603 Obj_Entry *obj; 1604 int fd = -1; 1605 struct stat sb; 1606 char *path; 1607 1608 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1609 if (object_match_name(obj, name)) 1610 return obj; 1611 1612 path = find_library(name, refobj); 1613 if (path == NULL) 1614 return NULL; 1615 1616 /* 1617 * If we didn't find a match by pathname, open the file and check 1618 * again by device and inode. This avoids false mismatches caused 1619 * by multiple links or ".." in pathnames. 1620 * 1621 * To avoid a race, we open the file and use fstat() rather than 1622 * using stat(). 1623 */ 1624 if ((fd = open(path, O_RDONLY)) == -1) { 1625 _rtld_error("Cannot open \"%s\"", path); 1626 free(path); 1627 return NULL; 1628 } 1629 if (fstat(fd, &sb) == -1) { 1630 _rtld_error("Cannot fstat \"%s\"", path); 1631 close(fd); 1632 free(path); 1633 return NULL; 1634 } 1635 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1636 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1637 break; 1638 if (obj != NULL) { 1639 object_add_name(obj, name); 1640 free(path); 1641 close(fd); 1642 return obj; 1643 } 1644 if (flags & RTLD_LO_NOLOAD) { 1645 free(path); 1646 close(fd); 1647 return (NULL); 1648 } 1649 1650 /* First use of this object, so we must map it in */ 1651 obj = do_load_object(fd, name, path, &sb, flags); 1652 if (obj == NULL) 1653 free(path); 1654 close(fd); 1655 1656 return obj; 1657 } 1658 1659 static Obj_Entry * 1660 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1661 int flags) 1662 { 1663 Obj_Entry *obj; 1664 struct statfs fs; 1665 1666 /* 1667 * but first, make sure that environment variables haven't been 1668 * used to circumvent the noexec flag on a filesystem. 1669 */ 1670 if (dangerous_ld_env) { 1671 if (fstatfs(fd, &fs) != 0) { 1672 _rtld_error("Cannot fstatfs \"%s\"", path); 1673 return NULL; 1674 } 1675 if (fs.f_flags & MNT_NOEXEC) { 1676 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1677 return NULL; 1678 } 1679 } 1680 dbg("loading \"%s\"", path); 1681 obj = map_object(fd, path, sbp); 1682 if (obj == NULL) 1683 return NULL; 1684 1685 object_add_name(obj, name); 1686 obj->path = path; 1687 digest_dynamic(obj, 0); 1688 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1689 RTLD_LO_DLOPEN) { 1690 dbg("refusing to load non-loadable \"%s\"", obj->path); 1691 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1692 munmap(obj->mapbase, obj->mapsize); 1693 obj_free(obj); 1694 return (NULL); 1695 } 1696 1697 *obj_tail = obj; 1698 obj_tail = &obj->next; 1699 obj_count++; 1700 obj_loads++; 1701 linkmap_add(obj); /* for GDB & dlinfo() */ 1702 1703 dbg(" %p .. %p: %s", obj->mapbase, 1704 obj->mapbase + obj->mapsize - 1, obj->path); 1705 if (obj->textrel) 1706 dbg(" WARNING: %s has impure text", obj->path); 1707 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1708 obj->path); 1709 1710 return obj; 1711 } 1712 1713 static Obj_Entry * 1714 obj_from_addr(const void *addr) 1715 { 1716 Obj_Entry *obj; 1717 1718 for (obj = obj_list; obj != NULL; obj = obj->next) { 1719 if (addr < (void *) obj->mapbase) 1720 continue; 1721 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1722 return obj; 1723 } 1724 return NULL; 1725 } 1726 1727 /* 1728 * Call the finalization functions for each of the objects in "list" 1729 * belonging to the DAG of "root" and referenced once. If NULL "root" 1730 * is specified, every finalization function will be called regardless 1731 * of the reference count and the list elements won't be freed. All of 1732 * the objects are expected to have non-NULL fini functions. 1733 */ 1734 static void 1735 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1736 { 1737 Objlist_Entry *elm; 1738 char *saved_msg; 1739 1740 assert(root == NULL || root->refcount == 1); 1741 1742 /* 1743 * Preserve the current error message since a fini function might 1744 * call into the dynamic linker and overwrite it. 1745 */ 1746 saved_msg = errmsg_save(); 1747 do { 1748 STAILQ_FOREACH(elm, list, link) { 1749 if (root != NULL && (elm->obj->refcount != 1 || 1750 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1751 continue; 1752 dbg("calling fini function for %s at %p", elm->obj->path, 1753 (void *)elm->obj->fini); 1754 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1755 elm->obj->path); 1756 /* Remove object from fini list to prevent recursive invocation. */ 1757 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1758 /* 1759 * XXX: If a dlopen() call references an object while the 1760 * fini function is in progress, we might end up trying to 1761 * unload the referenced object in dlclose() or the object 1762 * won't be unloaded although its fini function has been 1763 * called. 1764 */ 1765 lock_release(rtld_bind_lock, lockstate); 1766 call_initfini_pointer(elm->obj, elm->obj->fini); 1767 wlock_acquire(rtld_bind_lock, lockstate); 1768 /* No need to free anything if process is going down. */ 1769 if (root != NULL) 1770 free(elm); 1771 /* 1772 * We must restart the list traversal after every fini call 1773 * because a dlclose() call from the fini function or from 1774 * another thread might have modified the reference counts. 1775 */ 1776 break; 1777 } 1778 } while (elm != NULL); 1779 errmsg_restore(saved_msg); 1780 } 1781 1782 /* 1783 * Call the initialization functions for each of the objects in 1784 * "list". All of the objects are expected to have non-NULL init 1785 * functions. 1786 */ 1787 static void 1788 objlist_call_init(Objlist *list, RtldLockState *lockstate) 1789 { 1790 Objlist_Entry *elm; 1791 Obj_Entry *obj; 1792 char *saved_msg; 1793 1794 /* 1795 * Clean init_scanned flag so that objects can be rechecked and 1796 * possibly initialized earlier if any of vectors called below 1797 * cause the change by using dlopen. 1798 */ 1799 for (obj = obj_list; obj != NULL; obj = obj->next) 1800 obj->init_scanned = false; 1801 1802 /* 1803 * Preserve the current error message since an init function might 1804 * call into the dynamic linker and overwrite it. 1805 */ 1806 saved_msg = errmsg_save(); 1807 STAILQ_FOREACH(elm, list, link) { 1808 if (elm->obj->init_done) /* Initialized early. */ 1809 continue; 1810 dbg("calling init function for %s at %p", elm->obj->path, 1811 (void *)elm->obj->init); 1812 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1813 elm->obj->path); 1814 /* 1815 * Race: other thread might try to use this object before current 1816 * one completes the initilization. Not much can be done here 1817 * without better locking. 1818 */ 1819 elm->obj->init_done = true; 1820 lock_release(rtld_bind_lock, lockstate); 1821 call_initfini_pointer(elm->obj, elm->obj->init); 1822 wlock_acquire(rtld_bind_lock, lockstate); 1823 } 1824 errmsg_restore(saved_msg); 1825 } 1826 1827 static void 1828 objlist_clear(Objlist *list) 1829 { 1830 Objlist_Entry *elm; 1831 1832 while (!STAILQ_EMPTY(list)) { 1833 elm = STAILQ_FIRST(list); 1834 STAILQ_REMOVE_HEAD(list, link); 1835 free(elm); 1836 } 1837 } 1838 1839 static Objlist_Entry * 1840 objlist_find(Objlist *list, const Obj_Entry *obj) 1841 { 1842 Objlist_Entry *elm; 1843 1844 STAILQ_FOREACH(elm, list, link) 1845 if (elm->obj == obj) 1846 return elm; 1847 return NULL; 1848 } 1849 1850 static void 1851 objlist_init(Objlist *list) 1852 { 1853 STAILQ_INIT(list); 1854 } 1855 1856 static void 1857 objlist_push_head(Objlist *list, Obj_Entry *obj) 1858 { 1859 Objlist_Entry *elm; 1860 1861 elm = NEW(Objlist_Entry); 1862 elm->obj = obj; 1863 STAILQ_INSERT_HEAD(list, elm, link); 1864 } 1865 1866 static void 1867 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1868 { 1869 Objlist_Entry *elm; 1870 1871 elm = NEW(Objlist_Entry); 1872 elm->obj = obj; 1873 STAILQ_INSERT_TAIL(list, elm, link); 1874 } 1875 1876 static void 1877 objlist_remove(Objlist *list, Obj_Entry *obj) 1878 { 1879 Objlist_Entry *elm; 1880 1881 if ((elm = objlist_find(list, obj)) != NULL) { 1882 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1883 free(elm); 1884 } 1885 } 1886 1887 /* 1888 * Relocate newly-loaded shared objects. The argument is a pointer to 1889 * the Obj_Entry for the first such object. All objects from the first 1890 * to the end of the list of objects are relocated. Returns 0 on success, 1891 * or -1 on failure. 1892 */ 1893 static int 1894 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 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)) 1920 return -1; 1921 1922 /* 1923 * Reprotect the text segment. Make sure it is included in the 1924 * core dump since we modified it. This unfortunately causes the 1925 * entire text segment to core-out but we don't have much of a 1926 * choice. We could try to only reenable core dumps on pages 1927 * in which relocations occured but that is likely most of the text 1928 * pages anyway, and even that would not work because the rest of 1929 * the text pages would wind up as a read-only OBJT_DEFAULT object 1930 * (created due to our modifications) backed by the original OBJT_VNODE 1931 * object, and the ELF coredump code is currently only able to dump 1932 * vnode records for pure vnode-backed mappings, not vnode backings 1933 * to memory objects. 1934 */ 1935 if (obj->textrel) { 1936 madvise(obj->mapbase, obj->textsize, MADV_CORE); 1937 if (mprotect(obj->mapbase, obj->textsize, 1938 PROT_READ|PROT_EXEC) == -1) { 1939 _rtld_error("%s: Cannot write-protect text segment: %s", 1940 obj->path, strerror(errno)); 1941 return -1; 1942 } 1943 } 1944 1945 /* Process the PLT relocations. */ 1946 if (reloc_plt(obj) == -1) 1947 return -1; 1948 /* Relocate the jump slots if we are doing immediate binding. */ 1949 if (obj->bind_now || bind_now) 1950 if (reloc_jmpslots(obj) == -1) 1951 return -1; 1952 1953 /* Set the special PLT or GOT entries. */ 1954 init_pltgot(obj); 1955 1956 /* 1957 * Set up the magic number and version in the Obj_Entry. These 1958 * were checked in the crt1.o from the original ElfKit, so we 1959 * set them for backward compatibility. 1960 */ 1961 obj->magic = RTLD_MAGIC; 1962 obj->version = RTLD_VERSION; 1963 1964 /* 1965 * Set relocated data to read-only status if protection specified 1966 */ 1967 1968 if (obj->relro_size) { 1969 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 1970 _rtld_error("%s: Cannot enforce relro relocation: %s", 1971 obj->path, strerror(errno)); 1972 return -1; 1973 } 1974 } 1975 } 1976 1977 return (0); 1978 } 1979 1980 /* 1981 * Cleanup procedure. It will be called (by the atexit mechanism) just 1982 * before the process exits. 1983 */ 1984 static void 1985 rtld_exit(void) 1986 { 1987 RtldLockState lockstate; 1988 1989 wlock_acquire(rtld_bind_lock, &lockstate); 1990 dbg("rtld_exit()"); 1991 objlist_call_fini(&list_fini, NULL, &lockstate); 1992 /* No need to remove the items from the list, since we are exiting. */ 1993 if (!libmap_disable) 1994 lm_fini(); 1995 lock_release(rtld_bind_lock, &lockstate); 1996 } 1997 1998 static void * 1999 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2000 { 2001 if (path == NULL) 2002 return (NULL); 2003 2004 path += strspn(path, ":;"); 2005 while (*path != '\0') { 2006 size_t len; 2007 char *res; 2008 2009 len = strcspn(path, ":;"); 2010 res = callback(path, len, arg); 2011 2012 if (res != NULL) 2013 return (res); 2014 2015 path += len; 2016 path += strspn(path, ":;"); 2017 } 2018 2019 return (NULL); 2020 } 2021 2022 struct try_library_args { 2023 const char *name; 2024 size_t namelen; 2025 char *buffer; 2026 size_t buflen; 2027 }; 2028 2029 static void * 2030 try_library_path(const char *dir, size_t dirlen, void *param) 2031 { 2032 struct try_library_args *arg; 2033 2034 arg = param; 2035 if (*dir == '/' || trust) { 2036 char *pathname; 2037 2038 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2039 return (NULL); 2040 2041 pathname = arg->buffer; 2042 strncpy(pathname, dir, dirlen); 2043 pathname[dirlen] = '/'; 2044 strcpy(pathname + dirlen + 1, arg->name); 2045 2046 dbg(" Trying \"%s\"", pathname); 2047 if (access(pathname, F_OK) == 0) { /* We found it */ 2048 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2049 strcpy(pathname, arg->buffer); 2050 return (pathname); 2051 } 2052 } 2053 return (NULL); 2054 } 2055 2056 static char * 2057 search_library_path(const char *name, const char *path) 2058 { 2059 char *p; 2060 struct try_library_args arg; 2061 2062 if (path == NULL) 2063 return NULL; 2064 2065 arg.name = name; 2066 arg.namelen = strlen(name); 2067 arg.buffer = xmalloc(PATH_MAX); 2068 arg.buflen = PATH_MAX; 2069 2070 p = path_enumerate(path, try_library_path, &arg); 2071 2072 free(arg.buffer); 2073 2074 return (p); 2075 } 2076 2077 int 2078 dlclose(void *handle) 2079 { 2080 Obj_Entry *root; 2081 RtldLockState lockstate; 2082 2083 wlock_acquire(rtld_bind_lock, &lockstate); 2084 root = dlcheck(handle); 2085 if (root == NULL) { 2086 lock_release(rtld_bind_lock, &lockstate); 2087 return -1; 2088 } 2089 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2090 root->path); 2091 2092 /* Unreference the object and its dependencies. */ 2093 root->dl_refcount--; 2094 2095 if (root->refcount == 1) { 2096 /* 2097 * The object will be no longer referenced, so we must unload it. 2098 * First, call the fini functions. 2099 */ 2100 objlist_call_fini(&list_fini, root, &lockstate); 2101 2102 unref_dag(root); 2103 2104 /* Finish cleaning up the newly-unreferenced objects. */ 2105 GDB_STATE(RT_DELETE,&root->linkmap); 2106 unload_object(root); 2107 GDB_STATE(RT_CONSISTENT,NULL); 2108 } else 2109 unref_dag(root); 2110 2111 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2112 lock_release(rtld_bind_lock, &lockstate); 2113 return 0; 2114 } 2115 2116 char * 2117 dlerror(void) 2118 { 2119 char *msg = error_message; 2120 error_message = NULL; 2121 return msg; 2122 } 2123 2124 void * 2125 dlopen(const char *name, int mode) 2126 { 2127 Obj_Entry **old_obj_tail; 2128 Obj_Entry *obj; 2129 Objlist initlist; 2130 RtldLockState lockstate; 2131 int result, lo_flags; 2132 2133 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2134 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2135 if (ld_tracing != NULL) 2136 environ = (char **)*get_program_var_addr("environ"); 2137 lo_flags = RTLD_LO_DLOPEN; 2138 if (mode & RTLD_NODELETE) 2139 lo_flags |= RTLD_LO_NODELETE; 2140 if (mode & RTLD_NOLOAD) 2141 lo_flags |= RTLD_LO_NOLOAD; 2142 if (ld_tracing != NULL) 2143 lo_flags |= RTLD_LO_TRACE; 2144 2145 objlist_init(&initlist); 2146 2147 wlock_acquire(rtld_bind_lock, &lockstate); 2148 GDB_STATE(RT_ADD,NULL); 2149 2150 old_obj_tail = obj_tail; 2151 obj = NULL; 2152 if (name == NULL) { 2153 obj = obj_main; 2154 obj->refcount++; 2155 } else { 2156 obj = load_object(name, obj_main, lo_flags); 2157 } 2158 2159 if (obj) { 2160 obj->dl_refcount++; 2161 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2162 objlist_push_tail(&list_global, obj); 2163 mode &= RTLD_MODEMASK; 2164 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2165 assert(*old_obj_tail == obj); 2166 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2167 init_dag(obj); 2168 ref_dag(obj); 2169 if (result != -1) 2170 result = rtld_verify_versions(&obj->dagmembers); 2171 if (result != -1 && ld_tracing) 2172 goto trace; 2173 if (result == -1 || 2174 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2175 obj->dl_refcount--; 2176 unref_dag(obj); 2177 if (obj->refcount == 0) 2178 unload_object(obj); 2179 obj = NULL; 2180 } else { 2181 /* Make list of init functions to call. */ 2182 initlist_add_objects(obj, &obj->next, &initlist); 2183 } 2184 } else { 2185 2186 /* 2187 * Bump the reference counts for objects on this DAG. If 2188 * this is the first dlopen() call for the object that was 2189 * already loaded as a dependency, initialize the dag 2190 * starting at it. 2191 */ 2192 init_dag(obj); 2193 ref_dag(obj); 2194 2195 if ((lo_flags & RTLD_LO_TRACE) != 0) 2196 goto trace; 2197 } 2198 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2199 obj->z_nodelete) && !obj->ref_nodel) { 2200 dbg("obj %s nodelete", obj->path); 2201 ref_dag(obj); 2202 obj->z_nodelete = obj->ref_nodel = true; 2203 } 2204 } 2205 2206 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2207 name); 2208 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2209 2210 /* Call the init functions. */ 2211 objlist_call_init(&initlist, &lockstate); 2212 objlist_clear(&initlist); 2213 lock_release(rtld_bind_lock, &lockstate); 2214 return obj; 2215 trace: 2216 trace_loaded_objects(obj); 2217 lock_release(rtld_bind_lock, &lockstate); 2218 exit(0); 2219 } 2220 2221 static void * 2222 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2223 int flags) 2224 { 2225 DoneList donelist; 2226 const Obj_Entry *obj, *defobj; 2227 const Elf_Sym *def, *symp; 2228 unsigned long hash; 2229 RtldLockState lockstate; 2230 2231 hash = elf_hash(name); 2232 def = NULL; 2233 defobj = NULL; 2234 flags |= SYMLOOK_IN_PLT; 2235 2236 rlock_acquire(rtld_bind_lock, &lockstate); 2237 if (sigsetjmp(lockstate.env, 0) != 0) 2238 lock_upgrade(rtld_bind_lock, &lockstate); 2239 if (handle == NULL || handle == RTLD_NEXT || 2240 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2241 2242 if ((obj = obj_from_addr(retaddr)) == NULL) { 2243 _rtld_error("Cannot determine caller's shared object"); 2244 lock_release(rtld_bind_lock, &lockstate); 2245 return NULL; 2246 } 2247 if (handle == NULL) { /* Just the caller's shared object. */ 2248 def = symlook_obj(name, hash, obj, ve, flags); 2249 defobj = obj; 2250 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2251 handle == RTLD_SELF) { /* ... caller included */ 2252 if (handle == RTLD_NEXT) 2253 obj = obj->next; 2254 for (; obj != NULL; obj = obj->next) { 2255 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2256 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2257 def = symp; 2258 defobj = obj; 2259 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2260 break; 2261 } 2262 } 2263 } 2264 /* 2265 * Search the dynamic linker itself, and possibly resolve the 2266 * symbol from there. This is how the application links to 2267 * dynamic linker services such as dlopen. 2268 */ 2269 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2270 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2271 if (symp != NULL) { 2272 def = symp; 2273 defobj = &obj_rtld; 2274 } 2275 } 2276 } else { 2277 assert(handle == RTLD_DEFAULT); 2278 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2279 } 2280 } else { 2281 if ((obj = dlcheck(handle)) == NULL) { 2282 lock_release(rtld_bind_lock, &lockstate); 2283 return NULL; 2284 } 2285 2286 donelist_init(&donelist); 2287 if (obj->mainprog) { 2288 /* Search main program and all libraries loaded by it. */ 2289 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2290 &donelist); 2291 2292 /* 2293 * We do not distinguish between 'main' object and global scope. 2294 * If symbol is not defined by objects loaded at startup, continue 2295 * search among dynamically loaded objects with RTLD_GLOBAL 2296 * scope. 2297 */ 2298 if (def == NULL) 2299 def = symlook_list(name, hash, &list_global, &defobj, ve, 2300 flags, &donelist); 2301 } else { 2302 Needed_Entry fake; 2303 2304 /* Search the whole DAG rooted at the given object. */ 2305 fake.next = NULL; 2306 fake.obj = (Obj_Entry *)obj; 2307 fake.name = 0; 2308 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2309 &donelist); 2310 } 2311 } 2312 2313 if (def != NULL) { 2314 lock_release(rtld_bind_lock, &lockstate); 2315 2316 /* 2317 * The value required by the caller is derived from the value 2318 * of the symbol. For the ia64 architecture, we need to 2319 * construct a function descriptor which the caller can use to 2320 * call the function with the right 'gp' value. For other 2321 * architectures and for non-functions, the value is simply 2322 * the relocated value of the symbol. 2323 */ 2324 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2325 return (make_function_pointer(def, defobj)); 2326 else 2327 return (defobj->relocbase + def->st_value); 2328 } 2329 2330 _rtld_error("Undefined symbol \"%s\"", name); 2331 lock_release(rtld_bind_lock, &lockstate); 2332 return NULL; 2333 } 2334 2335 void * 2336 dlsym(void *handle, const char *name) 2337 { 2338 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2339 SYMLOOK_DLSYM); 2340 } 2341 2342 dlfunc_t 2343 dlfunc(void *handle, const char *name) 2344 { 2345 union { 2346 void *d; 2347 dlfunc_t f; 2348 } rv; 2349 2350 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2351 SYMLOOK_DLSYM); 2352 return (rv.f); 2353 } 2354 2355 void * 2356 dlvsym(void *handle, const char *name, const char *version) 2357 { 2358 Ver_Entry ventry; 2359 2360 ventry.name = version; 2361 ventry.file = NULL; 2362 ventry.hash = elf_hash(version); 2363 ventry.flags= 0; 2364 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2365 SYMLOOK_DLSYM); 2366 } 2367 2368 int 2369 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2370 { 2371 const Obj_Entry *obj; 2372 RtldLockState lockstate; 2373 2374 rlock_acquire(rtld_bind_lock, &lockstate); 2375 obj = obj_from_addr(addr); 2376 if (obj == NULL) { 2377 _rtld_error("No shared object contains address"); 2378 lock_release(rtld_bind_lock, &lockstate); 2379 return (0); 2380 } 2381 rtld_fill_dl_phdr_info(obj, phdr_info); 2382 lock_release(rtld_bind_lock, &lockstate); 2383 return (1); 2384 } 2385 2386 int 2387 dladdr(const void *addr, Dl_info *info) 2388 { 2389 const Obj_Entry *obj; 2390 const Elf_Sym *def; 2391 void *symbol_addr; 2392 unsigned long symoffset; 2393 RtldLockState lockstate; 2394 2395 rlock_acquire(rtld_bind_lock, &lockstate); 2396 obj = obj_from_addr(addr); 2397 if (obj == NULL) { 2398 _rtld_error("No shared object contains address"); 2399 lock_release(rtld_bind_lock, &lockstate); 2400 return 0; 2401 } 2402 info->dli_fname = obj->path; 2403 info->dli_fbase = obj->mapbase; 2404 info->dli_saddr = NULL; 2405 info->dli_sname = NULL; 2406 2407 /* 2408 * Walk the symbol list looking for the symbol whose address is 2409 * closest to the address sent in. 2410 */ 2411 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2412 def = obj->symtab + symoffset; 2413 2414 /* 2415 * For skip the symbol if st_shndx is either SHN_UNDEF or 2416 * SHN_COMMON. 2417 */ 2418 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2419 continue; 2420 2421 /* 2422 * If the symbol is greater than the specified address, or if it 2423 * is further away from addr than the current nearest symbol, 2424 * then reject it. 2425 */ 2426 symbol_addr = obj->relocbase + def->st_value; 2427 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2428 continue; 2429 2430 /* Update our idea of the nearest symbol. */ 2431 info->dli_sname = obj->strtab + def->st_name; 2432 info->dli_saddr = symbol_addr; 2433 2434 /* Exact match? */ 2435 if (info->dli_saddr == addr) 2436 break; 2437 } 2438 lock_release(rtld_bind_lock, &lockstate); 2439 return 1; 2440 } 2441 2442 int 2443 dlinfo(void *handle, int request, void *p) 2444 { 2445 const Obj_Entry *obj; 2446 RtldLockState lockstate; 2447 int error; 2448 2449 rlock_acquire(rtld_bind_lock, &lockstate); 2450 2451 if (handle == NULL || handle == RTLD_SELF) { 2452 void *retaddr; 2453 2454 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2455 if ((obj = obj_from_addr(retaddr)) == NULL) 2456 _rtld_error("Cannot determine caller's shared object"); 2457 } else 2458 obj = dlcheck(handle); 2459 2460 if (obj == NULL) { 2461 lock_release(rtld_bind_lock, &lockstate); 2462 return (-1); 2463 } 2464 2465 error = 0; 2466 switch (request) { 2467 case RTLD_DI_LINKMAP: 2468 *((struct link_map const **)p) = &obj->linkmap; 2469 break; 2470 case RTLD_DI_ORIGIN: 2471 error = rtld_dirname(obj->path, p); 2472 break; 2473 2474 case RTLD_DI_SERINFOSIZE: 2475 case RTLD_DI_SERINFO: 2476 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2477 break; 2478 2479 default: 2480 _rtld_error("Invalid request %d passed to dlinfo()", request); 2481 error = -1; 2482 } 2483 2484 lock_release(rtld_bind_lock, &lockstate); 2485 2486 return (error); 2487 } 2488 2489 static void 2490 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2491 { 2492 2493 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2494 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2495 STAILQ_FIRST(&obj->names)->name : obj->path; 2496 phdr_info->dlpi_phdr = obj->phdr; 2497 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2498 phdr_info->dlpi_tls_modid = obj->tlsindex; 2499 phdr_info->dlpi_tls_data = obj->tlsinit; 2500 phdr_info->dlpi_adds = obj_loads; 2501 phdr_info->dlpi_subs = obj_loads - obj_count; 2502 } 2503 2504 int 2505 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2506 { 2507 struct dl_phdr_info phdr_info; 2508 const Obj_Entry *obj; 2509 RtldLockState bind_lockstate, phdr_lockstate; 2510 int error; 2511 2512 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2513 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2514 2515 error = 0; 2516 2517 for (obj = obj_list; obj != NULL; obj = obj->next) { 2518 rtld_fill_dl_phdr_info(obj, &phdr_info); 2519 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2520 break; 2521 2522 } 2523 lock_release(rtld_bind_lock, &bind_lockstate); 2524 lock_release(rtld_phdr_lock, &phdr_lockstate); 2525 2526 return (error); 2527 } 2528 2529 struct fill_search_info_args { 2530 int request; 2531 unsigned int flags; 2532 Dl_serinfo *serinfo; 2533 Dl_serpath *serpath; 2534 char *strspace; 2535 }; 2536 2537 static void * 2538 fill_search_info(const char *dir, size_t dirlen, void *param) 2539 { 2540 struct fill_search_info_args *arg; 2541 2542 arg = param; 2543 2544 if (arg->request == RTLD_DI_SERINFOSIZE) { 2545 arg->serinfo->dls_cnt ++; 2546 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2547 } else { 2548 struct dl_serpath *s_entry; 2549 2550 s_entry = arg->serpath; 2551 s_entry->dls_name = arg->strspace; 2552 s_entry->dls_flags = arg->flags; 2553 2554 strncpy(arg->strspace, dir, dirlen); 2555 arg->strspace[dirlen] = '\0'; 2556 2557 arg->strspace += dirlen + 1; 2558 arg->serpath++; 2559 } 2560 2561 return (NULL); 2562 } 2563 2564 static int 2565 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2566 { 2567 struct dl_serinfo _info; 2568 struct fill_search_info_args args; 2569 2570 args.request = RTLD_DI_SERINFOSIZE; 2571 args.serinfo = &_info; 2572 2573 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2574 _info.dls_cnt = 0; 2575 2576 path_enumerate(ld_library_path, fill_search_info, &args); 2577 path_enumerate(obj->rpath, fill_search_info, &args); 2578 path_enumerate(gethints(), fill_search_info, &args); 2579 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2580 2581 2582 if (request == RTLD_DI_SERINFOSIZE) { 2583 info->dls_size = _info.dls_size; 2584 info->dls_cnt = _info.dls_cnt; 2585 return (0); 2586 } 2587 2588 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2589 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2590 return (-1); 2591 } 2592 2593 args.request = RTLD_DI_SERINFO; 2594 args.serinfo = info; 2595 args.serpath = &info->dls_serpath[0]; 2596 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2597 2598 args.flags = LA_SER_LIBPATH; 2599 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2600 return (-1); 2601 2602 args.flags = LA_SER_RUNPATH; 2603 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2604 return (-1); 2605 2606 args.flags = LA_SER_CONFIG; 2607 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2608 return (-1); 2609 2610 args.flags = LA_SER_DEFAULT; 2611 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2612 return (-1); 2613 return (0); 2614 } 2615 2616 static int 2617 rtld_dirname(const char *path, char *bname) 2618 { 2619 const char *endp; 2620 2621 /* Empty or NULL string gets treated as "." */ 2622 if (path == NULL || *path == '\0') { 2623 bname[0] = '.'; 2624 bname[1] = '\0'; 2625 return (0); 2626 } 2627 2628 /* Strip trailing slashes */ 2629 endp = path + strlen(path) - 1; 2630 while (endp > path && *endp == '/') 2631 endp--; 2632 2633 /* Find the start of the dir */ 2634 while (endp > path && *endp != '/') 2635 endp--; 2636 2637 /* Either the dir is "/" or there are no slashes */ 2638 if (endp == path) { 2639 bname[0] = *endp == '/' ? '/' : '.'; 2640 bname[1] = '\0'; 2641 return (0); 2642 } else { 2643 do { 2644 endp--; 2645 } while (endp > path && *endp == '/'); 2646 } 2647 2648 if (endp - path + 2 > PATH_MAX) 2649 { 2650 _rtld_error("Filename is too long: %s", path); 2651 return(-1); 2652 } 2653 2654 strncpy(bname, path, endp - path + 1); 2655 bname[endp - path + 1] = '\0'; 2656 return (0); 2657 } 2658 2659 static int 2660 rtld_dirname_abs(const char *path, char *base) 2661 { 2662 char base_rel[PATH_MAX]; 2663 2664 if (rtld_dirname(path, base) == -1) 2665 return (-1); 2666 if (base[0] == '/') 2667 return (0); 2668 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2669 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2670 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2671 return (-1); 2672 strcpy(base, base_rel); 2673 return (0); 2674 } 2675 2676 static void 2677 linkmap_add(Obj_Entry *obj) 2678 { 2679 struct link_map *l = &obj->linkmap; 2680 struct link_map *prev; 2681 2682 obj->linkmap.l_name = obj->path; 2683 obj->linkmap.l_addr = obj->mapbase; 2684 obj->linkmap.l_ld = obj->dynamic; 2685 #ifdef __mips__ 2686 /* GDB needs load offset on MIPS to use the symbols */ 2687 obj->linkmap.l_offs = obj->relocbase; 2688 #endif 2689 2690 if (r_debug.r_map == NULL) { 2691 r_debug.r_map = l; 2692 return; 2693 } 2694 2695 /* 2696 * Scan to the end of the list, but not past the entry for the 2697 * dynamic linker, which we want to keep at the very end. 2698 */ 2699 for (prev = r_debug.r_map; 2700 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2701 prev = prev->l_next) 2702 ; 2703 2704 /* Link in the new entry. */ 2705 l->l_prev = prev; 2706 l->l_next = prev->l_next; 2707 if (l->l_next != NULL) 2708 l->l_next->l_prev = l; 2709 prev->l_next = l; 2710 } 2711 2712 static void 2713 linkmap_delete(Obj_Entry *obj) 2714 { 2715 struct link_map *l = &obj->linkmap; 2716 2717 if (l->l_prev == NULL) { 2718 if ((r_debug.r_map = l->l_next) != NULL) 2719 l->l_next->l_prev = NULL; 2720 return; 2721 } 2722 2723 if ((l->l_prev->l_next = l->l_next) != NULL) 2724 l->l_next->l_prev = l->l_prev; 2725 } 2726 2727 /* 2728 * Function for the debugger to set a breakpoint on to gain control. 2729 * 2730 * The two parameters allow the debugger to easily find and determine 2731 * what the runtime loader is doing and to whom it is doing it. 2732 * 2733 * When the loadhook trap is hit (r_debug_state, set at program 2734 * initialization), the arguments can be found on the stack: 2735 * 2736 * +8 struct link_map *m 2737 * +4 struct r_debug *rd 2738 * +0 RetAddr 2739 */ 2740 void 2741 r_debug_state(struct r_debug* rd, struct link_map *m) 2742 { 2743 /* 2744 * The following is a hack to force the compiler to emit calls to 2745 * this function, even when optimizing. If the function is empty, 2746 * the compiler is not obliged to emit any code for calls to it, 2747 * even when marked __noinline. However, gdb depends on those 2748 * calls being made. 2749 */ 2750 __asm __volatile("" : : : "memory"); 2751 } 2752 2753 /* 2754 * Get address of the pointer variable in the main program. 2755 */ 2756 static const void ** 2757 get_program_var_addr(const char *name) 2758 { 2759 const Obj_Entry *obj; 2760 unsigned long hash; 2761 2762 hash = elf_hash(name); 2763 for (obj = obj_main; obj != NULL; obj = obj->next) { 2764 const Elf_Sym *def; 2765 2766 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2767 const void **addr; 2768 2769 addr = (const void **)(obj->relocbase + def->st_value); 2770 return addr; 2771 } 2772 } 2773 return (NULL); 2774 } 2775 2776 /* 2777 * Set a pointer variable in the main program to the given value. This 2778 * is used to set key variables such as "environ" before any of the 2779 * init functions are called. 2780 */ 2781 static void 2782 set_program_var(const char *name, const void *value) 2783 { 2784 const void **addr; 2785 2786 if ((addr = get_program_var_addr(name)) != NULL) { 2787 dbg("\"%s\": *%p <-- %p", name, addr, value); 2788 *addr = value; 2789 } 2790 } 2791 2792 /* 2793 * This is a special version of getenv which is far more efficient 2794 * at finding LD_ environment vars. 2795 */ 2796 static 2797 const char * 2798 _getenv_ld(const char *id) 2799 { 2800 const char *envp; 2801 int i, j; 2802 int idlen = strlen(id); 2803 2804 if (ld_index == LD_ARY_CACHE) 2805 return(getenv(id)); 2806 if (ld_index == 0) { 2807 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 2808 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 2809 ld_ary[j++] = envp; 2810 } 2811 if (j == 0) 2812 ld_ary[j++] = ""; 2813 ld_index = j; 2814 } 2815 for (i = ld_index - 1; i >= 0; --i) { 2816 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 2817 return(ld_ary[i] + idlen + 1); 2818 } 2819 return(NULL); 2820 } 2821 2822 /* 2823 * Given a symbol name in a referencing object, find the corresponding 2824 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2825 * no definition was found. Returns a pointer to the Obj_Entry of the 2826 * defining object via the reference parameter DEFOBJ_OUT. 2827 */ 2828 static const Elf_Sym * 2829 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2830 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2831 { 2832 DoneList donelist; 2833 const Elf_Sym *def; 2834 const Elf_Sym *symp; 2835 const Obj_Entry *obj; 2836 const Obj_Entry *defobj; 2837 const Objlist_Entry *elm; 2838 def = NULL; 2839 defobj = NULL; 2840 donelist_init(&donelist); 2841 2842 /* Look first in the referencing object if linked symbolically. */ 2843 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2844 symp = symlook_obj(name, hash, refobj, ventry, flags); 2845 if (symp != NULL) { 2846 def = symp; 2847 defobj = refobj; 2848 } 2849 } 2850 2851 /* Search all objects loaded at program start up. */ 2852 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2853 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2854 &donelist); 2855 if (symp != NULL && 2856 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2857 def = symp; 2858 defobj = obj; 2859 } 2860 } 2861 2862 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2863 STAILQ_FOREACH(elm, &list_global, link) { 2864 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2865 break; 2866 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2867 flags, &donelist); 2868 if (symp != NULL && 2869 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2870 def = symp; 2871 defobj = obj; 2872 } 2873 } 2874 2875 /* Search all dlopened DAGs containing the referencing object. */ 2876 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2877 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2878 break; 2879 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2880 flags, &donelist); 2881 if (symp != NULL && 2882 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2883 def = symp; 2884 defobj = obj; 2885 } 2886 } 2887 2888 /* 2889 * Search the dynamic linker itself, and possibly resolve the 2890 * symbol from there. This is how the application links to 2891 * dynamic linker services such as dlopen. Only the values listed 2892 * in the "exports" array can be resolved from the dynamic linker. 2893 */ 2894 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2895 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2896 if (symp != NULL && is_exported(symp)) { 2897 def = symp; 2898 defobj = &obj_rtld; 2899 } 2900 } 2901 2902 if (def != NULL) 2903 *defobj_out = defobj; 2904 return def; 2905 } 2906 2907 static const Elf_Sym * 2908 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2909 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2910 DoneList *dlp) 2911 { 2912 const Elf_Sym *symp; 2913 const Elf_Sym *def; 2914 const Obj_Entry *defobj; 2915 const Objlist_Entry *elm; 2916 2917 def = NULL; 2918 defobj = NULL; 2919 STAILQ_FOREACH(elm, objlist, link) { 2920 if (donelist_check(dlp, elm->obj)) 2921 continue; 2922 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2923 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2924 def = symp; 2925 defobj = elm->obj; 2926 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2927 break; 2928 } 2929 } 2930 } 2931 if (def != NULL) 2932 *defobj_out = defobj; 2933 return def; 2934 } 2935 2936 /* 2937 * Search the symbol table of a shared object and all objects needed 2938 * by it for a symbol of the given name. Search order is 2939 * breadth-first. Returns a pointer to the symbol, or NULL if no 2940 * definition was found. 2941 */ 2942 static const Elf_Sym * 2943 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2944 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2945 DoneList *dlp) 2946 { 2947 const Elf_Sym *def, *def_w; 2948 const Needed_Entry *n; 2949 const Obj_Entry *obj, *defobj, *defobj1; 2950 2951 def = def_w = NULL; 2952 defobj = NULL; 2953 for (n = needed; n != NULL; n = n->next) { 2954 if ((obj = n->obj) == NULL || 2955 donelist_check(dlp, obj) || 2956 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2957 continue; 2958 defobj = obj; 2959 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2960 *defobj_out = defobj; 2961 return (def); 2962 } 2963 } 2964 /* 2965 * There we come when either symbol definition is not found in 2966 * directly needed objects, or found symbol is weak. 2967 */ 2968 for (n = needed; n != NULL; n = n->next) { 2969 if ((obj = n->obj) == NULL) 2970 continue; 2971 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2972 ventry, flags, dlp); 2973 if (def_w == NULL) 2974 continue; 2975 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2976 def = def_w; 2977 defobj = defobj1; 2978 } 2979 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2980 break; 2981 } 2982 if (def != NULL) 2983 *defobj_out = defobj; 2984 return (def); 2985 } 2986 2987 /* 2988 * Search the symbol table of a single shared object for a symbol of 2989 * the given name and version, if requested. Returns a pointer to the 2990 * symbol, or NULL if no definition was found. 2991 * 2992 * The symbol's hash value is passed in for efficiency reasons; that 2993 * eliminates many recomputations of the hash value. 2994 */ 2995 const Elf_Sym * 2996 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2997 const Ver_Entry *ventry, int flags) 2998 { 2999 unsigned long symnum; 3000 const Elf_Sym *vsymp; 3001 Elf_Versym verndx; 3002 int vcount; 3003 3004 if (obj->buckets == NULL) 3005 return NULL; 3006 3007 vsymp = NULL; 3008 vcount = 0; 3009 symnum = obj->buckets[hash % obj->nbuckets]; 3010 3011 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3012 const Elf_Sym *symp; 3013 const char *strp; 3014 3015 if (symnum >= obj->nchains) 3016 return NULL; /* Bad object */ 3017 3018 symp = obj->symtab + symnum; 3019 strp = obj->strtab + symp->st_name; 3020 3021 switch (ELF_ST_TYPE(symp->st_info)) { 3022 case STT_FUNC: 3023 case STT_NOTYPE: 3024 case STT_OBJECT: 3025 if (symp->st_value == 0) 3026 continue; 3027 /* fallthrough */ 3028 case STT_TLS: 3029 if (symp->st_shndx != SHN_UNDEF) 3030 break; 3031 else if (((flags & SYMLOOK_IN_PLT) == 0) && 3032 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3033 break; 3034 /* fallthrough */ 3035 default: 3036 continue; 3037 } 3038 if (name[0] != strp[0] || strcmp(name, strp) != 0) 3039 continue; 3040 3041 if (ventry == NULL) { 3042 if (obj->versyms != NULL) { 3043 verndx = VER_NDX(obj->versyms[symnum]); 3044 if (verndx > obj->vernum) { 3045 _rtld_error("%s: symbol %s references wrong version %d", 3046 obj->path, obj->strtab + symnum, verndx); 3047 continue; 3048 } 3049 /* 3050 * If we are not called from dlsym (i.e. this is a normal 3051 * relocation from unversioned binary), accept the symbol 3052 * immediately if it happens to have first version after 3053 * this shared object became versioned. Otherwise, if 3054 * symbol is versioned and not hidden, remember it. If it 3055 * is the only symbol with this name exported by the 3056 * shared object, it will be returned as a match at the 3057 * end of the function. If symbol is global (verndx < 2) 3058 * accept it unconditionally. 3059 */ 3060 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 3061 return symp; 3062 else if (verndx >= VER_NDX_GIVEN) { 3063 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3064 if (vsymp == NULL) 3065 vsymp = symp; 3066 vcount ++; 3067 } 3068 continue; 3069 } 3070 } 3071 return symp; 3072 } else { 3073 if (obj->versyms == NULL) { 3074 if (object_match_name(obj, ventry->name)) { 3075 _rtld_error("%s: object %s should provide version %s for " 3076 "symbol %s", obj_rtld.path, obj->path, ventry->name, 3077 obj->strtab + symnum); 3078 continue; 3079 } 3080 } else { 3081 verndx = VER_NDX(obj->versyms[symnum]); 3082 if (verndx > obj->vernum) { 3083 _rtld_error("%s: symbol %s references wrong version %d", 3084 obj->path, obj->strtab + symnum, verndx); 3085 continue; 3086 } 3087 if (obj->vertab[verndx].hash != ventry->hash || 3088 strcmp(obj->vertab[verndx].name, ventry->name)) { 3089 /* 3090 * Version does not match. Look if this is a global symbol 3091 * and if it is not hidden. If global symbol (verndx < 2) 3092 * is available, use it. Do not return symbol if we are 3093 * called by dlvsym, because dlvsym looks for a specific 3094 * version and default one is not what dlvsym wants. 3095 */ 3096 if ((flags & SYMLOOK_DLSYM) || 3097 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3098 (verndx >= VER_NDX_GIVEN)) 3099 continue; 3100 } 3101 } 3102 return symp; 3103 } 3104 } 3105 return (vcount == 1) ? vsymp : NULL; 3106 } 3107 3108 static void 3109 trace_loaded_objects(Obj_Entry *obj) 3110 { 3111 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3112 int c; 3113 3114 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3115 main_local = ""; 3116 3117 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3118 fmt1 = "\t%o => %p (%x)\n"; 3119 3120 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3121 fmt2 = "\t%o (%x)\n"; 3122 3123 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 3124 3125 for (; obj; obj = obj->next) { 3126 Needed_Entry *needed; 3127 char *name, *path; 3128 bool is_lib; 3129 3130 if (list_containers && obj->needed != NULL) 3131 printf("%s:\n", obj->path); 3132 for (needed = obj->needed; needed; needed = needed->next) { 3133 if (needed->obj != NULL) { 3134 if (needed->obj->traced && !list_containers) 3135 continue; 3136 needed->obj->traced = true; 3137 path = needed->obj->path; 3138 } else 3139 path = "not found"; 3140 3141 name = (char *)obj->strtab + needed->name; 3142 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3143 3144 fmt = is_lib ? fmt1 : fmt2; 3145 while ((c = *fmt++) != '\0') { 3146 switch (c) { 3147 default: 3148 putchar(c); 3149 continue; 3150 case '\\': 3151 switch (c = *fmt) { 3152 case '\0': 3153 continue; 3154 case 'n': 3155 putchar('\n'); 3156 break; 3157 case 't': 3158 putchar('\t'); 3159 break; 3160 } 3161 break; 3162 case '%': 3163 switch (c = *fmt) { 3164 case '\0': 3165 continue; 3166 case '%': 3167 default: 3168 putchar(c); 3169 break; 3170 case 'A': 3171 printf("%s", main_local); 3172 break; 3173 case 'a': 3174 printf("%s", obj_main->path); 3175 break; 3176 case 'o': 3177 printf("%s", name); 3178 break; 3179 case 'p': 3180 printf("%s", path); 3181 break; 3182 case 'x': 3183 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3184 break; 3185 } 3186 break; 3187 } 3188 ++fmt; 3189 } 3190 } 3191 } 3192 } 3193 3194 /* 3195 * Unload a dlopened object and its dependencies from memory and from 3196 * our data structures. It is assumed that the DAG rooted in the 3197 * object has already been unreferenced, and that the object has a 3198 * reference count of 0. 3199 */ 3200 static void 3201 unload_object(Obj_Entry *root) 3202 { 3203 Obj_Entry *obj; 3204 Obj_Entry **linkp; 3205 3206 assert(root->refcount == 0); 3207 3208 /* 3209 * Pass over the DAG removing unreferenced objects from 3210 * appropriate lists. 3211 */ 3212 unlink_object(root); 3213 3214 /* Unmap all objects that are no longer referenced. */ 3215 linkp = &obj_list->next; 3216 while ((obj = *linkp) != NULL) { 3217 if (obj->refcount == 0) { 3218 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3219 obj->path); 3220 dbg("unloading \"%s\"", obj->path); 3221 munmap(obj->mapbase, obj->mapsize); 3222 linkmap_delete(obj); 3223 *linkp = obj->next; 3224 obj_count--; 3225 obj_free(obj); 3226 } else 3227 linkp = &obj->next; 3228 } 3229 obj_tail = linkp; 3230 } 3231 3232 static void 3233 unlink_object(Obj_Entry *root) 3234 { 3235 Objlist_Entry *elm; 3236 3237 if (root->refcount == 0) { 3238 /* Remove the object from the RTLD_GLOBAL list. */ 3239 objlist_remove(&list_global, root); 3240 3241 /* Remove the object from all objects' DAG lists. */ 3242 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3243 objlist_remove(&elm->obj->dldags, root); 3244 if (elm->obj != root) 3245 unlink_object(elm->obj); 3246 } 3247 } 3248 } 3249 3250 static void 3251 ref_dag(Obj_Entry *root) 3252 { 3253 Objlist_Entry *elm; 3254 3255 assert(root->dag_inited); 3256 STAILQ_FOREACH(elm, &root->dagmembers, link) 3257 elm->obj->refcount++; 3258 } 3259 3260 static void 3261 unref_dag(Obj_Entry *root) 3262 { 3263 Objlist_Entry *elm; 3264 3265 assert(root->dag_inited); 3266 STAILQ_FOREACH(elm, &root->dagmembers, link) 3267 elm->obj->refcount--; 3268 } 3269 3270 /* 3271 * Common code for MD __tls_get_addr(). 3272 */ 3273 void * 3274 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3275 { 3276 Elf_Addr* dtv = *dtvp; 3277 RtldLockState lockstate; 3278 3279 /* Check dtv generation in case new modules have arrived */ 3280 if (dtv[0] != tls_dtv_generation) { 3281 Elf_Addr* newdtv; 3282 int to_copy; 3283 3284 wlock_acquire(rtld_bind_lock, &lockstate); 3285 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3286 to_copy = dtv[1]; 3287 if (to_copy > tls_max_index) 3288 to_copy = tls_max_index; 3289 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3290 newdtv[0] = tls_dtv_generation; 3291 newdtv[1] = tls_max_index; 3292 free(dtv); 3293 lock_release(rtld_bind_lock, &lockstate); 3294 dtv = *dtvp = newdtv; 3295 } 3296 3297 /* Dynamically allocate module TLS if necessary */ 3298 if (!dtv[index + 1]) { 3299 /* Signal safe, wlock will block out signals. */ 3300 wlock_acquire(rtld_bind_lock, &lockstate); 3301 if (!dtv[index + 1]) 3302 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3303 lock_release(rtld_bind_lock, &lockstate); 3304 } 3305 return (void*) (dtv[index + 1] + offset); 3306 } 3307 3308 #if defined(RTLD_STATIC_TLS_VARIANT_II) 3309 3310 /* 3311 * Allocate the static TLS area. Return a pointer to the TCB. The 3312 * static area is based on negative offsets relative to the tcb. 3313 * 3314 * The TCB contains an errno pointer for the system call layer, but because 3315 * we are the RTLD we really have no idea how the caller was compiled so 3316 * the information has to be passed in. errno can either be: 3317 * 3318 * type 0 errno is a simple non-TLS global pointer. 3319 * (special case for e.g. libc_rtld) 3320 * type 1 errno accessed by GOT entry (dynamically linked programs) 3321 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 3322 */ 3323 struct tls_tcb * 3324 allocate_tls(Obj_Entry *objs) 3325 { 3326 Obj_Entry *obj; 3327 size_t data_size; 3328 size_t dtv_size; 3329 struct tls_tcb *tcb; 3330 Elf_Addr *dtv; 3331 Elf_Addr addr; 3332 3333 /* 3334 * Allocate the new TCB. static TLS storage is placed just before the 3335 * TCB to support the %gs:OFFSET (negative offset) model. 3336 */ 3337 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 3338 ~RTLD_STATIC_TLS_ALIGN_MASK; 3339 tcb = malloc(data_size + sizeof(*tcb)); 3340 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 3341 3342 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 3343 dtv = malloc(dtv_size); 3344 bzero(dtv, dtv_size); 3345 3346 #ifdef RTLD_TCB_HAS_SELF_POINTER 3347 tcb->tcb_self = tcb; 3348 #endif 3349 tcb->tcb_dtv = dtv; 3350 tcb->tcb_pthread = NULL; 3351 3352 dtv[0] = tls_dtv_generation; 3353 dtv[1] = tls_max_index; 3354 3355 for (obj = objs; obj; obj = obj->next) { 3356 if (obj->tlsoffset) { 3357 addr = (Elf_Addr)tcb - obj->tlsoffset; 3358 memset((void *)(addr + obj->tlsinitsize), 3359 0, obj->tlssize - obj->tlsinitsize); 3360 if (obj->tlsinit) 3361 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3362 dtv[obj->tlsindex + 1] = addr; 3363 } 3364 } 3365 return(tcb); 3366 } 3367 3368 void 3369 free_tls(struct tls_tcb *tcb) 3370 { 3371 Elf_Addr *dtv; 3372 int dtv_size, i; 3373 Elf_Addr tls_start, tls_end; 3374 size_t data_size; 3375 3376 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 3377 ~RTLD_STATIC_TLS_ALIGN_MASK; 3378 3379 dtv = tcb->tcb_dtv; 3380 dtv_size = dtv[1]; 3381 tls_end = (Elf_Addr)tcb; 3382 tls_start = (Elf_Addr)tcb - data_size; 3383 for (i = 0; i < dtv_size; i++) { 3384 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 3385 free((void *)dtv[i+2]); 3386 } 3387 } 3388 3389 free((void*) tls_start); 3390 } 3391 3392 #else 3393 #error "Unsupported TLS layout" 3394 #endif 3395 3396 /* 3397 * Allocate TLS block for module with given index. 3398 */ 3399 void * 3400 allocate_module_tls(int index) 3401 { 3402 Obj_Entry* obj; 3403 char* p; 3404 3405 for (obj = obj_list; obj; obj = obj->next) { 3406 if (obj->tlsindex == index) 3407 break; 3408 } 3409 if (!obj) { 3410 _rtld_error("Can't find module with TLS index %d", index); 3411 die(); 3412 } 3413 3414 p = malloc(obj->tlssize); 3415 if (p == NULL) { 3416 _rtld_error("Cannot allocate TLS block for index %d", index); 3417 die(); 3418 } 3419 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3420 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3421 3422 return p; 3423 } 3424 3425 bool 3426 allocate_tls_offset(Obj_Entry *obj) 3427 { 3428 size_t off; 3429 3430 if (obj->tls_done) 3431 return true; 3432 3433 if (obj->tlssize == 0) { 3434 obj->tls_done = true; 3435 return true; 3436 } 3437 3438 if (obj->tlsindex == 1) 3439 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3440 else 3441 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3442 obj->tlssize, obj->tlsalign); 3443 3444 /* 3445 * If we have already fixed the size of the static TLS block, we 3446 * must stay within that size. When allocating the static TLS, we 3447 * leave a small amount of space spare to be used for dynamically 3448 * loading modules which use static TLS. 3449 */ 3450 if (tls_static_space) { 3451 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3452 return false; 3453 } 3454 3455 tls_last_offset = obj->tlsoffset = off; 3456 tls_last_size = obj->tlssize; 3457 obj->tls_done = true; 3458 3459 return true; 3460 } 3461 3462 void 3463 free_tls_offset(Obj_Entry *obj) 3464 { 3465 #ifdef RTLD_STATIC_TLS_VARIANT_II 3466 /* 3467 * If we were the last thing to allocate out of the static TLS 3468 * block, we give our space back to the 'allocator'. This is a 3469 * simplistic workaround to allow libGL.so.1 to be loaded and 3470 * unloaded multiple times. We only handle the Variant II 3471 * mechanism for now - this really needs a proper allocator. 3472 */ 3473 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3474 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3475 tls_last_offset -= obj->tlssize; 3476 tls_last_size = 0; 3477 } 3478 #endif 3479 } 3480 3481 struct tls_tcb * 3482 _rtld_allocate_tls(void) 3483 { 3484 struct tls_tcb *new_tcb; 3485 RtldLockState lockstate; 3486 3487 wlock_acquire(rtld_bind_lock, &lockstate); 3488 new_tcb = allocate_tls(obj_list); 3489 lock_release(rtld_bind_lock, &lockstate); 3490 return (new_tcb); 3491 } 3492 3493 void 3494 _rtld_free_tls(struct tls_tcb *tcb) 3495 { 3496 RtldLockState lockstate; 3497 3498 wlock_acquire(rtld_bind_lock, &lockstate); 3499 free_tls(tcb); 3500 lock_release(rtld_bind_lock, &lockstate); 3501 } 3502 3503 static void 3504 object_add_name(Obj_Entry *obj, const char *name) 3505 { 3506 Name_Entry *entry; 3507 size_t len; 3508 3509 len = strlen(name); 3510 entry = malloc(sizeof(Name_Entry) + len); 3511 3512 if (entry != NULL) { 3513 strcpy(entry->name, name); 3514 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3515 } 3516 } 3517 3518 static int 3519 object_match_name(const Obj_Entry *obj, const char *name) 3520 { 3521 Name_Entry *entry; 3522 3523 STAILQ_FOREACH(entry, &obj->names, link) { 3524 if (strcmp(name, entry->name) == 0) 3525 return (1); 3526 } 3527 return (0); 3528 } 3529 3530 static Obj_Entry * 3531 locate_dependency(const Obj_Entry *obj, const char *name) 3532 { 3533 const Objlist_Entry *entry; 3534 const Needed_Entry *needed; 3535 3536 STAILQ_FOREACH(entry, &list_main, link) { 3537 if (object_match_name(entry->obj, name)) 3538 return entry->obj; 3539 } 3540 3541 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3542 if (strcmp(obj->strtab + needed->name, name) == 0 || 3543 (needed->obj != NULL && object_match_name(needed->obj, name))) { 3544 /* 3545 * If there is DT_NEEDED for the name we are looking for, 3546 * we are all set. Note that object might not be found if 3547 * dependency was not loaded yet, so the function can 3548 * return NULL here. This is expected and handled 3549 * properly by the caller. 3550 */ 3551 return (needed->obj); 3552 } 3553 } 3554 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3555 obj->path, name); 3556 die(); 3557 } 3558 3559 static int 3560 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3561 const Elf_Vernaux *vna) 3562 { 3563 const Elf_Verdef *vd; 3564 const char *vername; 3565 3566 vername = refobj->strtab + vna->vna_name; 3567 vd = depobj->verdef; 3568 if (vd == NULL) { 3569 _rtld_error("%s: version %s required by %s not defined", 3570 depobj->path, vername, refobj->path); 3571 return (-1); 3572 } 3573 for (;;) { 3574 if (vd->vd_version != VER_DEF_CURRENT) { 3575 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3576 depobj->path, vd->vd_version); 3577 return (-1); 3578 } 3579 if (vna->vna_hash == vd->vd_hash) { 3580 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3581 ((char *)vd + vd->vd_aux); 3582 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3583 return (0); 3584 } 3585 if (vd->vd_next == 0) 3586 break; 3587 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3588 } 3589 if (vna->vna_flags & VER_FLG_WEAK) 3590 return (0); 3591 _rtld_error("%s: version %s required by %s not found", 3592 depobj->path, vername, refobj->path); 3593 return (-1); 3594 } 3595 3596 static int 3597 rtld_verify_object_versions(Obj_Entry *obj) 3598 { 3599 const Elf_Verneed *vn; 3600 const Elf_Verdef *vd; 3601 const Elf_Verdaux *vda; 3602 const Elf_Vernaux *vna; 3603 const Obj_Entry *depobj; 3604 int maxvernum, vernum; 3605 3606 maxvernum = 0; 3607 /* 3608 * Walk over defined and required version records and figure out 3609 * max index used by any of them. Do very basic sanity checking 3610 * while there. 3611 */ 3612 vn = obj->verneed; 3613 while (vn != NULL) { 3614 if (vn->vn_version != VER_NEED_CURRENT) { 3615 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3616 obj->path, vn->vn_version); 3617 return (-1); 3618 } 3619 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3620 for (;;) { 3621 vernum = VER_NEED_IDX(vna->vna_other); 3622 if (vernum > maxvernum) 3623 maxvernum = vernum; 3624 if (vna->vna_next == 0) 3625 break; 3626 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3627 } 3628 if (vn->vn_next == 0) 3629 break; 3630 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3631 } 3632 3633 vd = obj->verdef; 3634 while (vd != NULL) { 3635 if (vd->vd_version != VER_DEF_CURRENT) { 3636 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3637 obj->path, vd->vd_version); 3638 return (-1); 3639 } 3640 vernum = VER_DEF_IDX(vd->vd_ndx); 3641 if (vernum > maxvernum) 3642 maxvernum = vernum; 3643 if (vd->vd_next == 0) 3644 break; 3645 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3646 } 3647 3648 if (maxvernum == 0) 3649 return (0); 3650 3651 /* 3652 * Store version information in array indexable by version index. 3653 * Verify that object version requirements are satisfied along the 3654 * way. 3655 */ 3656 obj->vernum = maxvernum + 1; 3657 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3658 3659 vd = obj->verdef; 3660 while (vd != NULL) { 3661 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3662 vernum = VER_DEF_IDX(vd->vd_ndx); 3663 assert(vernum <= maxvernum); 3664 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3665 obj->vertab[vernum].hash = vd->vd_hash; 3666 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3667 obj->vertab[vernum].file = NULL; 3668 obj->vertab[vernum].flags = 0; 3669 } 3670 if (vd->vd_next == 0) 3671 break; 3672 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3673 } 3674 3675 vn = obj->verneed; 3676 while (vn != NULL) { 3677 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3678 if (depobj == NULL) 3679 return (-1); 3680 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3681 for (;;) { 3682 if (check_object_provided_version(obj, depobj, vna)) 3683 return (-1); 3684 vernum = VER_NEED_IDX(vna->vna_other); 3685 assert(vernum <= maxvernum); 3686 obj->vertab[vernum].hash = vna->vna_hash; 3687 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3688 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3689 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3690 VER_INFO_HIDDEN : 0; 3691 if (vna->vna_next == 0) 3692 break; 3693 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3694 } 3695 if (vn->vn_next == 0) 3696 break; 3697 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3698 } 3699 return 0; 3700 } 3701 3702 static int 3703 rtld_verify_versions(const Objlist *objlist) 3704 { 3705 Objlist_Entry *entry; 3706 int rc; 3707 3708 rc = 0; 3709 STAILQ_FOREACH(entry, objlist, link) { 3710 /* 3711 * Skip dummy objects or objects that have their version requirements 3712 * already checked. 3713 */ 3714 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3715 continue; 3716 if (rtld_verify_object_versions(entry->obj) == -1) { 3717 rc = -1; 3718 if (ld_tracing == NULL) 3719 break; 3720 } 3721 } 3722 if (rc == 0 || ld_tracing != NULL) 3723 rc = rtld_verify_object_versions(&obj_rtld); 3724 return rc; 3725 } 3726 3727 const Ver_Entry * 3728 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3729 { 3730 Elf_Versym vernum; 3731 3732 if (obj->vertab) { 3733 vernum = VER_NDX(obj->versyms[symnum]); 3734 if (vernum >= obj->vernum) { 3735 _rtld_error("%s: symbol %s has wrong verneed value %d", 3736 obj->path, obj->strtab + symnum, vernum); 3737 } else if (obj->vertab[vernum].hash != 0) { 3738 return &obj->vertab[vernum]; 3739 } 3740 } 3741 return NULL; 3742 } 3743 3744 /* 3745 * No unresolved symbols for rtld. 3746 */ 3747 void 3748 __pthread_cxa_finalize(struct dl_phdr_info *a) 3749 { 3750 } 3751