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 *); 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 } 1136 if (nsegs < 1) { 1137 _rtld_error("%s: too few PT_LOAD segments", path); 1138 return NULL; 1139 } 1140 1141 obj->entry = entry; 1142 return obj; 1143 } 1144 1145 static Obj_Entry * 1146 dlcheck(void *handle) 1147 { 1148 Obj_Entry *obj; 1149 1150 for (obj = obj_list; obj != NULL; obj = obj->next) 1151 if (obj == (Obj_Entry *) handle) 1152 break; 1153 1154 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1155 _rtld_error("Invalid shared object handle %p", handle); 1156 return NULL; 1157 } 1158 return obj; 1159 } 1160 1161 /* 1162 * If the given object is already in the donelist, return true. Otherwise 1163 * add the object to the list and return false. 1164 */ 1165 static bool 1166 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1167 { 1168 unsigned int i; 1169 1170 for (i = 0; i < dlp->num_used; i++) 1171 if (dlp->objs[i] == obj) 1172 return true; 1173 /* 1174 * Our donelist allocation should always be sufficient. But if 1175 * our threads locking isn't working properly, more shared objects 1176 * could have been loaded since we allocated the list. That should 1177 * never happen, but we'll handle it properly just in case it does. 1178 */ 1179 if (dlp->num_used < dlp->num_alloc) 1180 dlp->objs[dlp->num_used++] = obj; 1181 return false; 1182 } 1183 1184 /* 1185 * Hash function for symbol table lookup. Don't even think about changing 1186 * this. It is specified by the System V ABI. 1187 */ 1188 unsigned long 1189 elf_hash(const char *name) 1190 { 1191 const unsigned char *p = (const unsigned char *) name; 1192 unsigned long h = 0; 1193 unsigned long g; 1194 1195 while (*p != '\0') { 1196 h = (h << 4) + *p++; 1197 if ((g = h & 0xf0000000) != 0) 1198 h ^= g >> 24; 1199 h &= ~g; 1200 } 1201 return h; 1202 } 1203 1204 /* 1205 * Find the library with the given name, and return its full pathname. 1206 * The returned string is dynamically allocated. Generates an error 1207 * message and returns NULL if the library cannot be found. 1208 * 1209 * If the second argument is non-NULL, then it refers to an already- 1210 * loaded shared object, whose library search path will be searched. 1211 * 1212 * The search order is: 1213 * LD_LIBRARY_PATH 1214 * rpath in the referencing file 1215 * ldconfig hints 1216 * /usr/lib 1217 */ 1218 static char * 1219 find_library(const char *xname, const Obj_Entry *refobj) 1220 { 1221 char *pathname; 1222 char *name; 1223 1224 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1225 if (xname[0] != '/' && !trust) { 1226 _rtld_error("Absolute pathname required for shared object \"%s\"", 1227 xname); 1228 return NULL; 1229 } 1230 if (refobj != NULL && refobj->z_origin) 1231 return origin_subst(xname, refobj->origin_path); 1232 else 1233 return xstrdup(xname); 1234 } 1235 1236 if (libmap_disable || (refobj == NULL) || 1237 (name = lm_find(refobj->path, xname)) == NULL) 1238 name = (char *)xname; 1239 1240 dbg(" Searching for \"%s\"", name); 1241 1242 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1243 (refobj != NULL && 1244 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1245 (pathname = search_library_path(name, gethints())) != NULL || 1246 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1247 return pathname; 1248 1249 if(refobj != NULL && refobj->path != NULL) { 1250 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1251 name, basename(refobj->path)); 1252 } else { 1253 _rtld_error("Shared object \"%s\" not found", name); 1254 } 1255 return NULL; 1256 } 1257 1258 /* 1259 * Given a symbol number in a referencing object, find the corresponding 1260 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1261 * no definition was found. Returns a pointer to the Obj_Entry of the 1262 * defining object via the reference parameter DEFOBJ_OUT. 1263 */ 1264 const Elf_Sym * 1265 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1266 const Obj_Entry **defobj_out, int flags, SymCache *cache) 1267 { 1268 const Elf_Sym *ref; 1269 const Elf_Sym *def; 1270 const Obj_Entry *defobj; 1271 const Ver_Entry *ventry; 1272 const char *name; 1273 unsigned long hash; 1274 1275 /* 1276 * If we have already found this symbol, get the information from 1277 * the cache. 1278 */ 1279 if (symnum >= refobj->nchains) 1280 return NULL; /* Bad object */ 1281 if (cache != NULL && cache[symnum].sym != NULL) { 1282 *defobj_out = cache[symnum].obj; 1283 return cache[symnum].sym; 1284 } 1285 1286 ref = refobj->symtab + symnum; 1287 name = refobj->strtab + ref->st_name; 1288 defobj = NULL; 1289 1290 /* 1291 * We don't have to do a full scale lookup if the symbol is local. 1292 * We know it will bind to the instance in this load module; to 1293 * which we already have a pointer (ie ref). By not doing a lookup, 1294 * we not only improve performance, but it also avoids unresolvable 1295 * symbols when local symbols are not in the hash table. 1296 * 1297 * This might occur for TLS module relocations, which simply use 1298 * symbol 0. 1299 */ 1300 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1301 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1302 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1303 symnum); 1304 } 1305 ventry = fetch_ventry(refobj, symnum); 1306 hash = elf_hash(name); 1307 def = symlook_default(name, hash, refobj, &defobj, ventry, flags); 1308 } else { 1309 def = ref; 1310 defobj = refobj; 1311 } 1312 1313 /* 1314 * If we found no definition and the reference is weak, treat the 1315 * symbol as having the value zero. 1316 */ 1317 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1318 def = &sym_zero; 1319 defobj = obj_main; 1320 } 1321 1322 if (def != NULL) { 1323 *defobj_out = defobj; 1324 /* Record the information in the cache to avoid subsequent lookups. */ 1325 if (cache != NULL) { 1326 cache[symnum].sym = def; 1327 cache[symnum].obj = defobj; 1328 } 1329 } else { 1330 if (refobj != &obj_rtld) 1331 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1332 } 1333 return def; 1334 } 1335 1336 /* 1337 * Return the search path from the ldconfig hints file, reading it if 1338 * necessary. Returns NULL if there are problems with the hints file, 1339 * or if the search path there is empty. 1340 */ 1341 static const char * 1342 gethints(void) 1343 { 1344 static char *hints; 1345 1346 if (hints == NULL) { 1347 int fd; 1348 struct elfhints_hdr hdr; 1349 char *p; 1350 1351 /* Keep from trying again in case the hints file is bad. */ 1352 hints = ""; 1353 1354 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1355 return NULL; 1356 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1357 hdr.magic != ELFHINTS_MAGIC || 1358 hdr.version != 1) { 1359 close(fd); 1360 return NULL; 1361 } 1362 p = xmalloc(hdr.dirlistlen + 1); 1363 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1364 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1365 free(p); 1366 close(fd); 1367 return NULL; 1368 } 1369 hints = p; 1370 close(fd); 1371 } 1372 return hints[0] != '\0' ? hints : NULL; 1373 } 1374 1375 static void 1376 init_dag(Obj_Entry *root) 1377 { 1378 DoneList donelist; 1379 1380 if (root->dag_inited) 1381 return; 1382 donelist_init(&donelist); 1383 init_dag1(root, root, &donelist); 1384 } 1385 1386 static void 1387 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) 1388 { 1389 const Needed_Entry *needed; 1390 1391 if (donelist_check(dlp, obj)) 1392 return; 1393 1394 objlist_push_tail(&obj->dldags, root); 1395 objlist_push_tail(&root->dagmembers, obj); 1396 for (needed = obj->needed; needed != NULL; needed = needed->next) 1397 if (needed->obj != NULL) 1398 init_dag1(root, needed->obj, dlp); 1399 root->dag_inited = true; 1400 } 1401 1402 /* 1403 * Initialize the dynamic linker. The argument is the address at which 1404 * the dynamic linker has been mapped into memory. The primary task of 1405 * this function is to relocate the dynamic linker. 1406 */ 1407 static void 1408 init_rtld(caddr_t mapbase) 1409 { 1410 Obj_Entry objtmp; /* Temporary rtld object */ 1411 1412 /* 1413 * Conjure up an Obj_Entry structure for the dynamic linker. 1414 * 1415 * The "path" member can't be initialized yet because string constants 1416 * cannot yet be accessed. Below we will set it correctly. 1417 */ 1418 memset(&objtmp, 0, sizeof(objtmp)); 1419 objtmp.path = NULL; 1420 objtmp.rtld = true; 1421 objtmp.mapbase = mapbase; 1422 #ifdef PIC 1423 objtmp.relocbase = mapbase; 1424 #endif 1425 if (RTLD_IS_DYNAMIC()) { 1426 objtmp.dynamic = rtld_dynamic(&objtmp); 1427 digest_dynamic(&objtmp, 1); 1428 assert(objtmp.needed == NULL); 1429 assert(!objtmp.textrel); 1430 1431 /* 1432 * Temporarily put the dynamic linker entry into the object list, so 1433 * that symbols can be found. 1434 */ 1435 1436 relocate_objects(&objtmp, true, &objtmp); 1437 } 1438 1439 /* Initialize the object list. */ 1440 obj_tail = &obj_list; 1441 1442 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1443 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1444 1445 /* Replace the path with a dynamically allocated copy. */ 1446 obj_rtld.path = xstrdup(PATH_RTLD); 1447 1448 r_debug.r_brk = r_debug_state; 1449 r_debug.r_state = RT_CONSISTENT; 1450 } 1451 1452 /* 1453 * Add the init functions from a needed object list (and its recursive 1454 * needed objects) to "list". This is not used directly; it is a helper 1455 * function for initlist_add_objects(). The write lock must be held 1456 * when this function is called. 1457 */ 1458 static void 1459 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1460 { 1461 /* Recursively process the successor needed objects. */ 1462 if (needed->next != NULL) 1463 initlist_add_neededs(needed->next, list); 1464 1465 /* Process the current needed object. */ 1466 if (needed->obj != NULL) 1467 initlist_add_objects(needed->obj, &needed->obj->next, list); 1468 } 1469 1470 /* 1471 * Scan all of the DAGs rooted in the range of objects from "obj" to 1472 * "tail" and add their init functions to "list". This recurses over 1473 * the DAGs and ensure the proper init ordering such that each object's 1474 * needed libraries are initialized before the object itself. At the 1475 * same time, this function adds the objects to the global finalization 1476 * list "list_fini" in the opposite order. The write lock must be 1477 * held when this function is called. 1478 */ 1479 static void 1480 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1481 { 1482 if (obj->init_scanned || obj->init_done) 1483 return; 1484 obj->init_scanned = true; 1485 1486 /* Recursively process the successor objects. */ 1487 if (&obj->next != tail) 1488 initlist_add_objects(obj->next, tail, list); 1489 1490 /* Recursively process the needed objects. */ 1491 if (obj->needed != NULL) 1492 initlist_add_neededs(obj->needed, list); 1493 1494 /* Add the object to the init list. */ 1495 if (obj->init != (Elf_Addr)NULL) 1496 objlist_push_tail(list, obj); 1497 1498 /* Add the object to the global fini list in the reverse order. */ 1499 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1500 objlist_push_head(&list_fini, obj); 1501 obj->on_fini_list = true; 1502 } 1503 } 1504 1505 #ifndef FPTR_TARGET 1506 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1507 #endif 1508 1509 static bool 1510 is_exported(const Elf_Sym *def) 1511 { 1512 Elf_Addr value; 1513 const func_ptr_type *p; 1514 1515 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1516 for (p = exports; *p != NULL; p++) 1517 if (FPTR_TARGET(*p) == value) 1518 return true; 1519 return false; 1520 } 1521 1522 /* 1523 * Given a shared object, traverse its list of needed objects, and load 1524 * each of them. Returns 0 on success. Generates an error message and 1525 * returns -1 on failure. 1526 */ 1527 static int 1528 load_needed_objects(Obj_Entry *first, int flags) 1529 { 1530 Obj_Entry *obj, *obj1; 1531 1532 for (obj = first; obj != NULL; obj = obj->next) { 1533 Needed_Entry *needed; 1534 1535 for (needed = obj->needed; needed != NULL; needed = needed->next) { 1536 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1537 flags & ~RTLD_LO_NOLOAD); 1538 if (obj1 == NULL && !ld_tracing) 1539 return -1; 1540 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1541 dbg("obj %s nodelete", obj1->path); 1542 init_dag(obj1); 1543 ref_dag(obj1); 1544 obj1->ref_nodel = true; 1545 } 1546 } 1547 } 1548 return (0); 1549 } 1550 1551 #define RTLD_FUNCTRACE "_rtld_functrace" 1552 1553 static int 1554 load_preload_objects(void) 1555 { 1556 char *p = ld_preload; 1557 static const char delim[] = " \t:;"; 1558 1559 if (p == NULL) 1560 return 0; 1561 1562 p += strspn(p, delim); 1563 while (*p != '\0') { 1564 size_t len = strcspn(p, delim); 1565 char savech; 1566 Obj_Entry *obj; 1567 const Elf_Sym *sym; 1568 1569 savech = p[len]; 1570 p[len] = '\0'; 1571 obj = load_object(p, NULL, 0); 1572 if (obj == NULL) 1573 return -1; /* XXX - cleanup */ 1574 p[len] = savech; 1575 p += len; 1576 p += strspn(p, delim); 1577 1578 /* Check for the magic tracing function */ 1579 sym = symlook_obj(RTLD_FUNCTRACE, elf_hash(RTLD_FUNCTRACE), obj, NULL, 1); 1580 if (sym != NULL) { 1581 rtld_functrace = (void *)(obj->relocbase + sym->st_value); 1582 rtld_functrace_obj = obj; 1583 } 1584 } 1585 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1586 return 0; 1587 } 1588 1589 /* 1590 * Load a shared object into memory, if it is not already loaded. 1591 * 1592 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1593 * on failure. 1594 */ 1595 static Obj_Entry * 1596 load_object(const char *name, const Obj_Entry *refobj, int flags) 1597 { 1598 Obj_Entry *obj; 1599 int fd = -1; 1600 struct stat sb; 1601 char *path; 1602 1603 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1604 if (object_match_name(obj, name)) 1605 return obj; 1606 1607 path = find_library(name, refobj); 1608 if (path == NULL) 1609 return NULL; 1610 1611 /* 1612 * If we didn't find a match by pathname, open the file and check 1613 * again by device and inode. This avoids false mismatches caused 1614 * by multiple links or ".." in pathnames. 1615 * 1616 * To avoid a race, we open the file and use fstat() rather than 1617 * using stat(). 1618 */ 1619 if ((fd = open(path, O_RDONLY)) == -1) { 1620 _rtld_error("Cannot open \"%s\"", path); 1621 free(path); 1622 return NULL; 1623 } 1624 if (fstat(fd, &sb) == -1) { 1625 _rtld_error("Cannot fstat \"%s\"", path); 1626 close(fd); 1627 free(path); 1628 return NULL; 1629 } 1630 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1631 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1632 break; 1633 if (obj != NULL) { 1634 object_add_name(obj, name); 1635 free(path); 1636 close(fd); 1637 return obj; 1638 } 1639 if (flags & RTLD_LO_NOLOAD) { 1640 free(path); 1641 return (NULL); 1642 } 1643 1644 /* First use of this object, so we must map it in */ 1645 obj = do_load_object(fd, name, path, &sb, flags); 1646 if (obj == NULL) 1647 free(path); 1648 close(fd); 1649 1650 return obj; 1651 } 1652 1653 static Obj_Entry * 1654 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1655 int flags) 1656 { 1657 Obj_Entry *obj; 1658 struct statfs fs; 1659 1660 /* 1661 * but first, make sure that environment variables haven't been 1662 * used to circumvent the noexec flag on a filesystem. 1663 */ 1664 if (dangerous_ld_env) { 1665 if (fstatfs(fd, &fs) != 0) { 1666 _rtld_error("Cannot fstatfs \"%s\"", path); 1667 return NULL; 1668 } 1669 if (fs.f_flags & MNT_NOEXEC) { 1670 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1671 return NULL; 1672 } 1673 } 1674 dbg("loading \"%s\"", path); 1675 obj = map_object(fd, path, sbp); 1676 if (obj == NULL) 1677 return NULL; 1678 1679 object_add_name(obj, name); 1680 obj->path = path; 1681 digest_dynamic(obj, 0); 1682 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1683 RTLD_LO_DLOPEN) { 1684 dbg("refusing to load non-loadable \"%s\"", obj->path); 1685 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1686 munmap(obj->mapbase, obj->mapsize); 1687 obj_free(obj); 1688 return (NULL); 1689 } 1690 1691 *obj_tail = obj; 1692 obj_tail = &obj->next; 1693 obj_count++; 1694 obj_loads++; 1695 linkmap_add(obj); /* for GDB & dlinfo() */ 1696 1697 dbg(" %p .. %p: %s", obj->mapbase, 1698 obj->mapbase + obj->mapsize - 1, obj->path); 1699 if (obj->textrel) 1700 dbg(" WARNING: %s has impure text", obj->path); 1701 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1702 obj->path); 1703 1704 return obj; 1705 } 1706 1707 static Obj_Entry * 1708 obj_from_addr(const void *addr) 1709 { 1710 Obj_Entry *obj; 1711 1712 for (obj = obj_list; obj != NULL; obj = obj->next) { 1713 if (addr < (void *) obj->mapbase) 1714 continue; 1715 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1716 return obj; 1717 } 1718 return NULL; 1719 } 1720 1721 /* 1722 * Call the finalization functions for each of the objects in "list" 1723 * belonging to the DAG of "root" and referenced once. If NULL "root" 1724 * is specified, every finalization function will be called regardless 1725 * of the reference count and the list elements won't be freed. All of 1726 * the objects are expected to have non-NULL fini functions. 1727 */ 1728 static void 1729 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1730 { 1731 Objlist_Entry *elm; 1732 char *saved_msg; 1733 1734 assert(root == NULL || root->refcount == 1); 1735 1736 /* 1737 * Preserve the current error message since a fini function might 1738 * call into the dynamic linker and overwrite it. 1739 */ 1740 saved_msg = errmsg_save(); 1741 do { 1742 STAILQ_FOREACH(elm, list, link) { 1743 if (root != NULL && (elm->obj->refcount != 1 || 1744 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1745 continue; 1746 dbg("calling fini function for %s at %p", elm->obj->path, 1747 (void *)elm->obj->fini); 1748 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1749 elm->obj->path); 1750 /* Remove object from fini list to prevent recursive invocation. */ 1751 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1752 /* 1753 * XXX: If a dlopen() call references an object while the 1754 * fini function is in progress, we might end up trying to 1755 * unload the referenced object in dlclose() or the object 1756 * won't be unloaded although its fini function has been 1757 * called. 1758 */ 1759 lock_release(rtld_bind_lock, lockstate); 1760 call_initfini_pointer(elm->obj, elm->obj->fini); 1761 wlock_acquire(rtld_bind_lock, lockstate); 1762 /* No need to free anything if process is going down. */ 1763 if (root != NULL) 1764 free(elm); 1765 /* 1766 * We must restart the list traversal after every fini call 1767 * because a dlclose() call from the fini function or from 1768 * another thread might have modified the reference counts. 1769 */ 1770 break; 1771 } 1772 } while (elm != NULL); 1773 errmsg_restore(saved_msg); 1774 } 1775 1776 /* 1777 * Call the initialization functions for each of the objects in 1778 * "list". All of the objects are expected to have non-NULL init 1779 * functions. 1780 */ 1781 static void 1782 objlist_call_init(Objlist *list, RtldLockState *lockstate) 1783 { 1784 Objlist_Entry *elm; 1785 Obj_Entry *obj; 1786 char *saved_msg; 1787 1788 /* 1789 * Clean init_scanned flag so that objects can be rechecked and 1790 * possibly initialized earlier if any of vectors called below 1791 * cause the change by using dlopen. 1792 */ 1793 for (obj = obj_list; obj != NULL; obj = obj->next) 1794 obj->init_scanned = false; 1795 1796 /* 1797 * Preserve the current error message since an init function might 1798 * call into the dynamic linker and overwrite it. 1799 */ 1800 saved_msg = errmsg_save(); 1801 STAILQ_FOREACH(elm, list, link) { 1802 if (elm->obj->init_done) /* Initialized early. */ 1803 continue; 1804 dbg("calling init function for %s at %p", elm->obj->path, 1805 (void *)elm->obj->init); 1806 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1807 elm->obj->path); 1808 /* 1809 * Race: other thread might try to use this object before current 1810 * one completes the initilization. Not much can be done here 1811 * without better locking. 1812 */ 1813 elm->obj->init_done = true; 1814 lock_release(rtld_bind_lock, lockstate); 1815 call_initfini_pointer(elm->obj, elm->obj->init); 1816 wlock_acquire(rtld_bind_lock, lockstate); 1817 } 1818 errmsg_restore(saved_msg); 1819 } 1820 1821 static void 1822 objlist_clear(Objlist *list) 1823 { 1824 Objlist_Entry *elm; 1825 1826 while (!STAILQ_EMPTY(list)) { 1827 elm = STAILQ_FIRST(list); 1828 STAILQ_REMOVE_HEAD(list, link); 1829 free(elm); 1830 } 1831 } 1832 1833 static Objlist_Entry * 1834 objlist_find(Objlist *list, const Obj_Entry *obj) 1835 { 1836 Objlist_Entry *elm; 1837 1838 STAILQ_FOREACH(elm, list, link) 1839 if (elm->obj == obj) 1840 return elm; 1841 return NULL; 1842 } 1843 1844 static void 1845 objlist_init(Objlist *list) 1846 { 1847 STAILQ_INIT(list); 1848 } 1849 1850 static void 1851 objlist_push_head(Objlist *list, Obj_Entry *obj) 1852 { 1853 Objlist_Entry *elm; 1854 1855 elm = NEW(Objlist_Entry); 1856 elm->obj = obj; 1857 STAILQ_INSERT_HEAD(list, elm, link); 1858 } 1859 1860 static void 1861 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1862 { 1863 Objlist_Entry *elm; 1864 1865 elm = NEW(Objlist_Entry); 1866 elm->obj = obj; 1867 STAILQ_INSERT_TAIL(list, elm, link); 1868 } 1869 1870 static void 1871 objlist_remove(Objlist *list, Obj_Entry *obj) 1872 { 1873 Objlist_Entry *elm; 1874 1875 if ((elm = objlist_find(list, obj)) != NULL) { 1876 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1877 free(elm); 1878 } 1879 } 1880 1881 /* 1882 * Relocate newly-loaded shared objects. The argument is a pointer to 1883 * the Obj_Entry for the first such object. All objects from the first 1884 * to the end of the list of objects are relocated. Returns 0 on success, 1885 * or -1 on failure. 1886 */ 1887 static int 1888 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj) 1889 { 1890 Obj_Entry *obj; 1891 1892 for (obj = first; obj != NULL; obj = obj->next) { 1893 if (obj != rtldobj) 1894 dbg("relocating \"%s\"", obj->path); 1895 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1896 obj->symtab == NULL || obj->strtab == NULL) { 1897 _rtld_error("%s: Shared object has no run-time symbol table", 1898 obj->path); 1899 return -1; 1900 } 1901 1902 if (obj->textrel) { 1903 /* There are relocations to the write-protected text segment. */ 1904 if (mprotect(obj->mapbase, obj->textsize, 1905 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1906 _rtld_error("%s: Cannot write-enable text segment: %s", 1907 obj->path, strerror(errno)); 1908 return -1; 1909 } 1910 } 1911 1912 /* Process the non-PLT relocations. */ 1913 if (reloc_non_plt(obj, rtldobj)) 1914 return -1; 1915 1916 /* 1917 * Reprotect the text segment. Make sure it is included in the 1918 * core dump since we modified it. This unfortunately causes the 1919 * entire text segment to core-out but we don't have much of a 1920 * choice. We could try to only reenable core dumps on pages 1921 * in which relocations occured but that is likely most of the text 1922 * pages anyway, and even that would not work because the rest of 1923 * the text pages would wind up as a read-only OBJT_DEFAULT object 1924 * (created due to our modifications) backed by the original OBJT_VNODE 1925 * object, and the ELF coredump code is currently only able to dump 1926 * vnode records for pure vnode-backed mappings, not vnode backings 1927 * to memory objects. 1928 */ 1929 if (obj->textrel) { 1930 madvise(obj->mapbase, obj->textsize, MADV_CORE); 1931 if (mprotect(obj->mapbase, obj->textsize, 1932 PROT_READ|PROT_EXEC) == -1) { 1933 _rtld_error("%s: Cannot write-protect text segment: %s", 1934 obj->path, strerror(errno)); 1935 return -1; 1936 } 1937 } 1938 1939 /* Process the PLT relocations. */ 1940 if (reloc_plt(obj) == -1) 1941 return -1; 1942 /* Relocate the jump slots if we are doing immediate binding. */ 1943 if (obj->bind_now || bind_now) 1944 if (reloc_jmpslots(obj) == -1) 1945 return -1; 1946 1947 1948 /* 1949 * Set up the magic number and version in the Obj_Entry. These 1950 * were checked in the crt1.o from the original ElfKit, so we 1951 * set them for backward compatibility. 1952 */ 1953 obj->magic = RTLD_MAGIC; 1954 obj->version = RTLD_VERSION; 1955 1956 /* Set the special PLT or GOT entries. */ 1957 init_pltgot(obj); 1958 } 1959 1960 return 0; 1961 } 1962 1963 /* 1964 * Cleanup procedure. It will be called (by the atexit mechanism) just 1965 * before the process exits. 1966 */ 1967 static void 1968 rtld_exit(void) 1969 { 1970 RtldLockState lockstate; 1971 1972 wlock_acquire(rtld_bind_lock, &lockstate); 1973 dbg("rtld_exit()"); 1974 objlist_call_fini(&list_fini, NULL, &lockstate); 1975 /* No need to remove the items from the list, since we are exiting. */ 1976 if (!libmap_disable) 1977 lm_fini(); 1978 lock_release(rtld_bind_lock, &lockstate); 1979 } 1980 1981 static void * 1982 path_enumerate(const char *path, path_enum_proc callback, void *arg) 1983 { 1984 if (path == NULL) 1985 return (NULL); 1986 1987 path += strspn(path, ":;"); 1988 while (*path != '\0') { 1989 size_t len; 1990 char *res; 1991 1992 len = strcspn(path, ":;"); 1993 res = callback(path, len, arg); 1994 1995 if (res != NULL) 1996 return (res); 1997 1998 path += len; 1999 path += strspn(path, ":;"); 2000 } 2001 2002 return (NULL); 2003 } 2004 2005 struct try_library_args { 2006 const char *name; 2007 size_t namelen; 2008 char *buffer; 2009 size_t buflen; 2010 }; 2011 2012 static void * 2013 try_library_path(const char *dir, size_t dirlen, void *param) 2014 { 2015 struct try_library_args *arg; 2016 2017 arg = param; 2018 if (*dir == '/' || trust) { 2019 char *pathname; 2020 2021 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2022 return (NULL); 2023 2024 pathname = arg->buffer; 2025 strncpy(pathname, dir, dirlen); 2026 pathname[dirlen] = '/'; 2027 strcpy(pathname + dirlen + 1, arg->name); 2028 2029 dbg(" Trying \"%s\"", pathname); 2030 if (access(pathname, F_OK) == 0) { /* We found it */ 2031 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2032 strcpy(pathname, arg->buffer); 2033 return (pathname); 2034 } 2035 } 2036 return (NULL); 2037 } 2038 2039 static char * 2040 search_library_path(const char *name, const char *path) 2041 { 2042 char *p; 2043 struct try_library_args arg; 2044 2045 if (path == NULL) 2046 return NULL; 2047 2048 arg.name = name; 2049 arg.namelen = strlen(name); 2050 arg.buffer = xmalloc(PATH_MAX); 2051 arg.buflen = PATH_MAX; 2052 2053 p = path_enumerate(path, try_library_path, &arg); 2054 2055 free(arg.buffer); 2056 2057 return (p); 2058 } 2059 2060 int 2061 dlclose(void *handle) 2062 { 2063 Obj_Entry *root; 2064 RtldLockState lockstate; 2065 2066 wlock_acquire(rtld_bind_lock, &lockstate); 2067 root = dlcheck(handle); 2068 if (root == NULL) { 2069 lock_release(rtld_bind_lock, &lockstate); 2070 return -1; 2071 } 2072 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2073 root->path); 2074 2075 /* Unreference the object and its dependencies. */ 2076 root->dl_refcount--; 2077 2078 if (root->refcount == 1) { 2079 /* 2080 * The object will be no longer referenced, so we must unload it. 2081 * First, call the fini functions. 2082 */ 2083 objlist_call_fini(&list_fini, root, &lockstate); 2084 2085 unref_dag(root); 2086 2087 /* Finish cleaning up the newly-unreferenced objects. */ 2088 GDB_STATE(RT_DELETE,&root->linkmap); 2089 unload_object(root); 2090 GDB_STATE(RT_CONSISTENT,NULL); 2091 } else 2092 unref_dag(root); 2093 2094 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2095 lock_release(rtld_bind_lock, &lockstate); 2096 return 0; 2097 } 2098 2099 char * 2100 dlerror(void) 2101 { 2102 char *msg = error_message; 2103 error_message = NULL; 2104 return msg; 2105 } 2106 2107 void * 2108 dlopen(const char *name, int mode) 2109 { 2110 Obj_Entry **old_obj_tail; 2111 Obj_Entry *obj; 2112 Objlist initlist; 2113 RtldLockState lockstate; 2114 int result, lo_flags; 2115 2116 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2117 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2118 if (ld_tracing != NULL) 2119 environ = (char **)*get_program_var_addr("environ"); 2120 lo_flags = RTLD_LO_DLOPEN; 2121 if (mode & RTLD_NODELETE) 2122 lo_flags |= RTLD_LO_NODELETE; 2123 if (mode & RTLD_NOLOAD) 2124 lo_flags |= RTLD_LO_NOLOAD; 2125 if (ld_tracing != NULL) 2126 lo_flags |= RTLD_LO_TRACE; 2127 2128 objlist_init(&initlist); 2129 2130 wlock_acquire(rtld_bind_lock, &lockstate); 2131 GDB_STATE(RT_ADD,NULL); 2132 2133 old_obj_tail = obj_tail; 2134 obj = NULL; 2135 if (name == NULL) { 2136 obj = obj_main; 2137 obj->refcount++; 2138 } else { 2139 obj = load_object(name, obj_main, lo_flags); 2140 } 2141 2142 if (obj) { 2143 obj->dl_refcount++; 2144 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2145 objlist_push_tail(&list_global, obj); 2146 mode &= RTLD_MODEMASK; 2147 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2148 assert(*old_obj_tail == obj); 2149 result = load_needed_objects(obj, RTLD_LO_DLOPEN); 2150 init_dag(obj); 2151 ref_dag(obj); 2152 if (result != -1) 2153 result = rtld_verify_versions(&obj->dagmembers); 2154 if (result != -1 && ld_tracing) 2155 goto trace; 2156 if (result == -1 || 2157 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) { 2158 obj->dl_refcount--; 2159 unref_dag(obj); 2160 if (obj->refcount == 0) 2161 unload_object(obj); 2162 obj = NULL; 2163 } else { 2164 /* Make list of init functions to call. */ 2165 initlist_add_objects(obj, &obj->next, &initlist); 2166 } 2167 } else { 2168 2169 /* 2170 * Bump the reference counts for objects on this DAG. If 2171 * this is the first dlopen() call for the object that was 2172 * already loaded as a dependency, initialize the dag 2173 * starting at it. 2174 */ 2175 init_dag(obj); 2176 ref_dag(obj); 2177 2178 if ((lo_flags & RTLD_LO_TRACE) != 0) 2179 goto trace; 2180 } 2181 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2182 obj->z_nodelete) && !obj->ref_nodel) { 2183 dbg("obj %s nodelete", obj->path); 2184 ref_dag(obj); 2185 obj->z_nodelete = obj->ref_nodel = true; 2186 } 2187 } 2188 2189 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2190 name); 2191 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2192 2193 /* Call the init functions. */ 2194 objlist_call_init(&initlist, &lockstate); 2195 objlist_clear(&initlist); 2196 lock_release(rtld_bind_lock, &lockstate); 2197 return obj; 2198 trace: 2199 trace_loaded_objects(obj); 2200 lock_release(rtld_bind_lock, &lockstate); 2201 exit(0); 2202 } 2203 2204 static void * 2205 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2206 int flags) 2207 { 2208 DoneList donelist; 2209 const Obj_Entry *obj, *defobj; 2210 const Elf_Sym *def, *symp; 2211 unsigned long hash; 2212 RtldLockState lockstate; 2213 2214 hash = elf_hash(name); 2215 def = NULL; 2216 defobj = NULL; 2217 flags |= SYMLOOK_IN_PLT; 2218 2219 rlock_acquire(rtld_bind_lock, &lockstate); 2220 if (sigsetjmp(lockstate.env, 0) != 0) 2221 lock_upgrade(rtld_bind_lock, &lockstate); 2222 if (handle == NULL || handle == RTLD_NEXT || 2223 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2224 2225 if ((obj = obj_from_addr(retaddr)) == NULL) { 2226 _rtld_error("Cannot determine caller's shared object"); 2227 lock_release(rtld_bind_lock, &lockstate); 2228 return NULL; 2229 } 2230 if (handle == NULL) { /* Just the caller's shared object. */ 2231 def = symlook_obj(name, hash, obj, ve, flags); 2232 defobj = obj; 2233 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2234 handle == RTLD_SELF) { /* ... caller included */ 2235 if (handle == RTLD_NEXT) 2236 obj = obj->next; 2237 for (; obj != NULL; obj = obj->next) { 2238 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) { 2239 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2240 def = symp; 2241 defobj = obj; 2242 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2243 break; 2244 } 2245 } 2246 } 2247 /* 2248 * Search the dynamic linker itself, and possibly resolve the 2249 * symbol from there. This is how the application links to 2250 * dynamic linker services such as dlopen. 2251 */ 2252 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2253 symp = symlook_obj(name, hash, &obj_rtld, ve, flags); 2254 if (symp != NULL) { 2255 def = symp; 2256 defobj = &obj_rtld; 2257 } 2258 } 2259 } else { 2260 assert(handle == RTLD_DEFAULT); 2261 def = symlook_default(name, hash, obj, &defobj, ve, flags); 2262 } 2263 } else { 2264 if ((obj = dlcheck(handle)) == NULL) { 2265 lock_release(rtld_bind_lock, &lockstate); 2266 return NULL; 2267 } 2268 2269 donelist_init(&donelist); 2270 if (obj->mainprog) { 2271 /* Search main program and all libraries loaded by it. */ 2272 def = symlook_list(name, hash, &list_main, &defobj, ve, flags, 2273 &donelist); 2274 2275 /* 2276 * We do not distinguish between 'main' object and global scope. 2277 * If symbol is not defined by objects loaded at startup, continue 2278 * search among dynamically loaded objects with RTLD_GLOBAL 2279 * scope. 2280 */ 2281 if (def == NULL) 2282 def = symlook_list(name, hash, &list_global, &defobj, ve, 2283 flags, &donelist); 2284 } else { 2285 Needed_Entry fake; 2286 2287 /* Search the whole DAG rooted at the given object. */ 2288 fake.next = NULL; 2289 fake.obj = (Obj_Entry *)obj; 2290 fake.name = 0; 2291 def = symlook_needed(name, hash, &fake, &defobj, ve, flags, 2292 &donelist); 2293 } 2294 } 2295 2296 if (def != NULL) { 2297 lock_release(rtld_bind_lock, &lockstate); 2298 2299 /* 2300 * The value required by the caller is derived from the value 2301 * of the symbol. For the ia64 architecture, we need to 2302 * construct a function descriptor which the caller can use to 2303 * call the function with the right 'gp' value. For other 2304 * architectures and for non-functions, the value is simply 2305 * the relocated value of the symbol. 2306 */ 2307 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2308 return make_function_pointer(def, defobj); 2309 else 2310 return defobj->relocbase + def->st_value; 2311 } 2312 2313 _rtld_error("Undefined symbol \"%s\"", name); 2314 lock_release(rtld_bind_lock, &lockstate); 2315 return NULL; 2316 } 2317 2318 void * 2319 dlsym(void *handle, const char *name) 2320 { 2321 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2322 SYMLOOK_DLSYM); 2323 } 2324 2325 dlfunc_t 2326 dlfunc(void *handle, const char *name) 2327 { 2328 union { 2329 void *d; 2330 dlfunc_t f; 2331 } rv; 2332 2333 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2334 SYMLOOK_DLSYM); 2335 return (rv.f); 2336 } 2337 2338 void * 2339 dlvsym(void *handle, const char *name, const char *version) 2340 { 2341 Ver_Entry ventry; 2342 2343 ventry.name = version; 2344 ventry.file = NULL; 2345 ventry.hash = elf_hash(version); 2346 ventry.flags= 0; 2347 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2348 SYMLOOK_DLSYM); 2349 } 2350 2351 int 2352 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2353 { 2354 const Obj_Entry *obj; 2355 RtldLockState lockstate; 2356 2357 rlock_acquire(rtld_bind_lock, &lockstate); 2358 obj = obj_from_addr(addr); 2359 if (obj == NULL) { 2360 _rtld_error("No shared object contains address"); 2361 lock_release(rtld_bind_lock, &lockstate); 2362 return (0); 2363 } 2364 rtld_fill_dl_phdr_info(obj, phdr_info); 2365 lock_release(rtld_bind_lock, &lockstate); 2366 return (1); 2367 } 2368 2369 int 2370 dladdr(const void *addr, Dl_info *info) 2371 { 2372 const Obj_Entry *obj; 2373 const Elf_Sym *def; 2374 void *symbol_addr; 2375 unsigned long symoffset; 2376 RtldLockState lockstate; 2377 2378 rlock_acquire(rtld_bind_lock, &lockstate); 2379 obj = obj_from_addr(addr); 2380 if (obj == NULL) { 2381 _rtld_error("No shared object contains address"); 2382 lock_release(rtld_bind_lock, &lockstate); 2383 return 0; 2384 } 2385 info->dli_fname = obj->path; 2386 info->dli_fbase = obj->mapbase; 2387 info->dli_saddr = NULL; 2388 info->dli_sname = NULL; 2389 2390 /* 2391 * Walk the symbol list looking for the symbol whose address is 2392 * closest to the address sent in. 2393 */ 2394 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2395 def = obj->symtab + symoffset; 2396 2397 /* 2398 * For skip the symbol if st_shndx is either SHN_UNDEF or 2399 * SHN_COMMON. 2400 */ 2401 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2402 continue; 2403 2404 /* 2405 * If the symbol is greater than the specified address, or if it 2406 * is further away from addr than the current nearest symbol, 2407 * then reject it. 2408 */ 2409 symbol_addr = obj->relocbase + def->st_value; 2410 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2411 continue; 2412 2413 /* Update our idea of the nearest symbol. */ 2414 info->dli_sname = obj->strtab + def->st_name; 2415 info->dli_saddr = symbol_addr; 2416 2417 /* Exact match? */ 2418 if (info->dli_saddr == addr) 2419 break; 2420 } 2421 lock_release(rtld_bind_lock, &lockstate); 2422 return 1; 2423 } 2424 2425 int 2426 dlinfo(void *handle, int request, void *p) 2427 { 2428 const Obj_Entry *obj; 2429 RtldLockState lockstate; 2430 int error; 2431 2432 rlock_acquire(rtld_bind_lock, &lockstate); 2433 2434 if (handle == NULL || handle == RTLD_SELF) { 2435 void *retaddr; 2436 2437 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2438 if ((obj = obj_from_addr(retaddr)) == NULL) 2439 _rtld_error("Cannot determine caller's shared object"); 2440 } else 2441 obj = dlcheck(handle); 2442 2443 if (obj == NULL) { 2444 lock_release(rtld_bind_lock, &lockstate); 2445 return (-1); 2446 } 2447 2448 error = 0; 2449 switch (request) { 2450 case RTLD_DI_LINKMAP: 2451 *((struct link_map const **)p) = &obj->linkmap; 2452 break; 2453 case RTLD_DI_ORIGIN: 2454 error = rtld_dirname(obj->path, p); 2455 break; 2456 2457 case RTLD_DI_SERINFOSIZE: 2458 case RTLD_DI_SERINFO: 2459 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2460 break; 2461 2462 default: 2463 _rtld_error("Invalid request %d passed to dlinfo()", request); 2464 error = -1; 2465 } 2466 2467 lock_release(rtld_bind_lock, &lockstate); 2468 2469 return (error); 2470 } 2471 2472 static void 2473 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2474 { 2475 2476 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2477 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2478 STAILQ_FIRST(&obj->names)->name : obj->path; 2479 phdr_info->dlpi_phdr = obj->phdr; 2480 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2481 phdr_info->dlpi_tls_modid = obj->tlsindex; 2482 phdr_info->dlpi_tls_data = obj->tlsinit; 2483 phdr_info->dlpi_adds = obj_loads; 2484 phdr_info->dlpi_subs = obj_loads - obj_count; 2485 } 2486 2487 int 2488 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2489 { 2490 struct dl_phdr_info phdr_info; 2491 const Obj_Entry *obj; 2492 RtldLockState bind_lockstate, phdr_lockstate; 2493 int error; 2494 2495 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2496 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2497 2498 error = 0; 2499 2500 for (obj = obj_list; obj != NULL; obj = obj->next) { 2501 rtld_fill_dl_phdr_info(obj, &phdr_info); 2502 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2503 break; 2504 2505 } 2506 lock_release(rtld_bind_lock, &bind_lockstate); 2507 lock_release(rtld_phdr_lock, &phdr_lockstate); 2508 2509 return (error); 2510 } 2511 2512 struct fill_search_info_args { 2513 int request; 2514 unsigned int flags; 2515 Dl_serinfo *serinfo; 2516 Dl_serpath *serpath; 2517 char *strspace; 2518 }; 2519 2520 static void * 2521 fill_search_info(const char *dir, size_t dirlen, void *param) 2522 { 2523 struct fill_search_info_args *arg; 2524 2525 arg = param; 2526 2527 if (arg->request == RTLD_DI_SERINFOSIZE) { 2528 arg->serinfo->dls_cnt ++; 2529 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2530 } else { 2531 struct dl_serpath *s_entry; 2532 2533 s_entry = arg->serpath; 2534 s_entry->dls_name = arg->strspace; 2535 s_entry->dls_flags = arg->flags; 2536 2537 strncpy(arg->strspace, dir, dirlen); 2538 arg->strspace[dirlen] = '\0'; 2539 2540 arg->strspace += dirlen + 1; 2541 arg->serpath++; 2542 } 2543 2544 return (NULL); 2545 } 2546 2547 static int 2548 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2549 { 2550 struct dl_serinfo _info; 2551 struct fill_search_info_args args; 2552 2553 args.request = RTLD_DI_SERINFOSIZE; 2554 args.serinfo = &_info; 2555 2556 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2557 _info.dls_cnt = 0; 2558 2559 path_enumerate(ld_library_path, fill_search_info, &args); 2560 path_enumerate(obj->rpath, fill_search_info, &args); 2561 path_enumerate(gethints(), fill_search_info, &args); 2562 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2563 2564 2565 if (request == RTLD_DI_SERINFOSIZE) { 2566 info->dls_size = _info.dls_size; 2567 info->dls_cnt = _info.dls_cnt; 2568 return (0); 2569 } 2570 2571 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2572 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2573 return (-1); 2574 } 2575 2576 args.request = RTLD_DI_SERINFO; 2577 args.serinfo = info; 2578 args.serpath = &info->dls_serpath[0]; 2579 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2580 2581 args.flags = LA_SER_LIBPATH; 2582 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2583 return (-1); 2584 2585 args.flags = LA_SER_RUNPATH; 2586 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2587 return (-1); 2588 2589 args.flags = LA_SER_CONFIG; 2590 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2591 return (-1); 2592 2593 args.flags = LA_SER_DEFAULT; 2594 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2595 return (-1); 2596 return (0); 2597 } 2598 2599 static int 2600 rtld_dirname(const char *path, char *bname) 2601 { 2602 const char *endp; 2603 2604 /* Empty or NULL string gets treated as "." */ 2605 if (path == NULL || *path == '\0') { 2606 bname[0] = '.'; 2607 bname[1] = '\0'; 2608 return (0); 2609 } 2610 2611 /* Strip trailing slashes */ 2612 endp = path + strlen(path) - 1; 2613 while (endp > path && *endp == '/') 2614 endp--; 2615 2616 /* Find the start of the dir */ 2617 while (endp > path && *endp != '/') 2618 endp--; 2619 2620 /* Either the dir is "/" or there are no slashes */ 2621 if (endp == path) { 2622 bname[0] = *endp == '/' ? '/' : '.'; 2623 bname[1] = '\0'; 2624 return (0); 2625 } else { 2626 do { 2627 endp--; 2628 } while (endp > path && *endp == '/'); 2629 } 2630 2631 if (endp - path + 2 > PATH_MAX) 2632 { 2633 _rtld_error("Filename is too long: %s", path); 2634 return(-1); 2635 } 2636 2637 strncpy(bname, path, endp - path + 1); 2638 bname[endp - path + 1] = '\0'; 2639 return (0); 2640 } 2641 2642 static int 2643 rtld_dirname_abs(const char *path, char *base) 2644 { 2645 char base_rel[PATH_MAX]; 2646 2647 if (rtld_dirname(path, base) == -1) 2648 return (-1); 2649 if (base[0] == '/') 2650 return (0); 2651 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2652 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2653 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2654 return (-1); 2655 strcpy(base, base_rel); 2656 return (0); 2657 } 2658 2659 static void 2660 linkmap_add(Obj_Entry *obj) 2661 { 2662 struct link_map *l = &obj->linkmap; 2663 struct link_map *prev; 2664 2665 obj->linkmap.l_name = obj->path; 2666 obj->linkmap.l_addr = obj->mapbase; 2667 obj->linkmap.l_ld = obj->dynamic; 2668 #ifdef __mips__ 2669 /* GDB needs load offset on MIPS to use the symbols */ 2670 obj->linkmap.l_offs = obj->relocbase; 2671 #endif 2672 2673 if (r_debug.r_map == NULL) { 2674 r_debug.r_map = l; 2675 return; 2676 } 2677 2678 /* 2679 * Scan to the end of the list, but not past the entry for the 2680 * dynamic linker, which we want to keep at the very end. 2681 */ 2682 for (prev = r_debug.r_map; 2683 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2684 prev = prev->l_next) 2685 ; 2686 2687 /* Link in the new entry. */ 2688 l->l_prev = prev; 2689 l->l_next = prev->l_next; 2690 if (l->l_next != NULL) 2691 l->l_next->l_prev = l; 2692 prev->l_next = l; 2693 } 2694 2695 static void 2696 linkmap_delete(Obj_Entry *obj) 2697 { 2698 struct link_map *l = &obj->linkmap; 2699 2700 if (l->l_prev == NULL) { 2701 if ((r_debug.r_map = l->l_next) != NULL) 2702 l->l_next->l_prev = NULL; 2703 return; 2704 } 2705 2706 if ((l->l_prev->l_next = l->l_next) != NULL) 2707 l->l_next->l_prev = l->l_prev; 2708 } 2709 2710 /* 2711 * Function for the debugger to set a breakpoint on to gain control. 2712 * 2713 * The two parameters allow the debugger to easily find and determine 2714 * what the runtime loader is doing and to whom it is doing it. 2715 * 2716 * When the loadhook trap is hit (r_debug_state, set at program 2717 * initialization), the arguments can be found on the stack: 2718 * 2719 * +8 struct link_map *m 2720 * +4 struct r_debug *rd 2721 * +0 RetAddr 2722 */ 2723 void 2724 r_debug_state(struct r_debug* rd, struct link_map *m) 2725 { 2726 } 2727 2728 /* 2729 * Get address of the pointer variable in the main program. 2730 */ 2731 static const void ** 2732 get_program_var_addr(const char *name) 2733 { 2734 const Obj_Entry *obj; 2735 unsigned long hash; 2736 2737 hash = elf_hash(name); 2738 for (obj = obj_main; obj != NULL; obj = obj->next) { 2739 const Elf_Sym *def; 2740 2741 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) { 2742 const void **addr; 2743 2744 addr = (const void **)(obj->relocbase + def->st_value); 2745 return addr; 2746 } 2747 } 2748 return (NULL); 2749 } 2750 2751 /* 2752 * Set a pointer variable in the main program to the given value. This 2753 * is used to set key variables such as "environ" before any of the 2754 * init functions are called. 2755 */ 2756 static void 2757 set_program_var(const char *name, const void *value) 2758 { 2759 const void **addr; 2760 2761 if ((addr = get_program_var_addr(name)) != NULL) { 2762 dbg("\"%s\": *%p <-- %p", name, addr, value); 2763 *addr = value; 2764 } 2765 } 2766 2767 /* 2768 * This is a special version of getenv which is far more efficient 2769 * at finding LD_ environment vars. 2770 */ 2771 static 2772 const char * 2773 _getenv_ld(const char *id) 2774 { 2775 const char *envp; 2776 int i, j; 2777 int idlen = strlen(id); 2778 2779 if (ld_index == LD_ARY_CACHE) 2780 return(getenv(id)); 2781 if (ld_index == 0) { 2782 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 2783 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 2784 ld_ary[j++] = envp; 2785 } 2786 if (j == 0) 2787 ld_ary[j++] = ""; 2788 ld_index = j; 2789 } 2790 for (i = ld_index - 1; i >= 0; --i) { 2791 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 2792 return(ld_ary[i] + idlen + 1); 2793 } 2794 return(NULL); 2795 } 2796 2797 /* 2798 * Given a symbol name in a referencing object, find the corresponding 2799 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2800 * no definition was found. Returns a pointer to the Obj_Entry of the 2801 * defining object via the reference parameter DEFOBJ_OUT. 2802 */ 2803 static const Elf_Sym * 2804 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj, 2805 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags) 2806 { 2807 DoneList donelist; 2808 const Elf_Sym *def; 2809 const Elf_Sym *symp; 2810 const Obj_Entry *obj; 2811 const Obj_Entry *defobj; 2812 const Objlist_Entry *elm; 2813 def = NULL; 2814 defobj = NULL; 2815 donelist_init(&donelist); 2816 2817 /* Look first in the referencing object if linked symbolically. */ 2818 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2819 symp = symlook_obj(name, hash, refobj, ventry, flags); 2820 if (symp != NULL) { 2821 def = symp; 2822 defobj = refobj; 2823 } 2824 } 2825 2826 /* Search all objects loaded at program start up. */ 2827 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2828 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags, 2829 &donelist); 2830 if (symp != NULL && 2831 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2832 def = symp; 2833 defobj = obj; 2834 } 2835 } 2836 2837 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2838 STAILQ_FOREACH(elm, &list_global, link) { 2839 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2840 break; 2841 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2842 flags, &donelist); 2843 if (symp != NULL && 2844 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2845 def = symp; 2846 defobj = obj; 2847 } 2848 } 2849 2850 /* Search all dlopened DAGs containing the referencing object. */ 2851 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2852 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) 2853 break; 2854 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry, 2855 flags, &donelist); 2856 if (symp != NULL && 2857 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { 2858 def = symp; 2859 defobj = obj; 2860 } 2861 } 2862 2863 /* 2864 * Search the dynamic linker itself, and possibly resolve the 2865 * symbol from there. This is how the application links to 2866 * dynamic linker services such as dlopen. Only the values listed 2867 * in the "exports" array can be resolved from the dynamic linker. 2868 */ 2869 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2870 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags); 2871 if (symp != NULL && is_exported(symp)) { 2872 def = symp; 2873 defobj = &obj_rtld; 2874 } 2875 } 2876 2877 if (def != NULL) 2878 *defobj_out = defobj; 2879 return def; 2880 } 2881 2882 static const Elf_Sym * 2883 symlook_list(const char *name, unsigned long hash, const Objlist *objlist, 2884 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2885 DoneList *dlp) 2886 { 2887 const Elf_Sym *symp; 2888 const Elf_Sym *def; 2889 const Obj_Entry *defobj; 2890 const Objlist_Entry *elm; 2891 2892 def = NULL; 2893 defobj = NULL; 2894 STAILQ_FOREACH(elm, objlist, link) { 2895 if (donelist_check(dlp, elm->obj)) 2896 continue; 2897 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) { 2898 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { 2899 def = symp; 2900 defobj = elm->obj; 2901 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2902 break; 2903 } 2904 } 2905 } 2906 if (def != NULL) 2907 *defobj_out = defobj; 2908 return def; 2909 } 2910 2911 /* 2912 * Search the symbol table of a shared object and all objects needed 2913 * by it for a symbol of the given name. Search order is 2914 * breadth-first. Returns a pointer to the symbol, or NULL if no 2915 * definition was found. 2916 */ 2917 static const Elf_Sym * 2918 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed, 2919 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags, 2920 DoneList *dlp) 2921 { 2922 const Elf_Sym *def, *def_w; 2923 const Needed_Entry *n; 2924 const Obj_Entry *obj, *defobj, *defobj1; 2925 2926 def = def_w = NULL; 2927 defobj = NULL; 2928 for (n = needed; n != NULL; n = n->next) { 2929 if ((obj = n->obj) == NULL || 2930 donelist_check(dlp, obj) || 2931 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL) 2932 continue; 2933 defobj = obj; 2934 if (ELF_ST_BIND(def->st_info) != STB_WEAK) { 2935 *defobj_out = defobj; 2936 return (def); 2937 } 2938 } 2939 /* 2940 * There we come when either symbol definition is not found in 2941 * directly needed objects, or found symbol is weak. 2942 */ 2943 for (n = needed; n != NULL; n = n->next) { 2944 if ((obj = n->obj) == NULL) 2945 continue; 2946 def_w = symlook_needed(name, hash, obj->needed, &defobj1, 2947 ventry, flags, dlp); 2948 if (def_w == NULL) 2949 continue; 2950 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) { 2951 def = def_w; 2952 defobj = defobj1; 2953 } 2954 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK) 2955 break; 2956 } 2957 if (def != NULL) 2958 *defobj_out = defobj; 2959 return (def); 2960 } 2961 2962 /* 2963 * Search the symbol table of a single shared object for a symbol of 2964 * the given name and version, if requested. Returns a pointer to the 2965 * symbol, or NULL if no definition was found. 2966 * 2967 * The symbol's hash value is passed in for efficiency reasons; that 2968 * eliminates many recomputations of the hash value. 2969 */ 2970 const Elf_Sym * 2971 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, 2972 const Ver_Entry *ventry, int flags) 2973 { 2974 unsigned long symnum; 2975 const Elf_Sym *vsymp; 2976 Elf_Versym verndx; 2977 int vcount; 2978 2979 if (obj->buckets == NULL) 2980 return NULL; 2981 2982 vsymp = NULL; 2983 vcount = 0; 2984 symnum = obj->buckets[hash % obj->nbuckets]; 2985 2986 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 2987 const Elf_Sym *symp; 2988 const char *strp; 2989 2990 if (symnum >= obj->nchains) 2991 return NULL; /* Bad object */ 2992 2993 symp = obj->symtab + symnum; 2994 strp = obj->strtab + symp->st_name; 2995 2996 switch (ELF_ST_TYPE(symp->st_info)) { 2997 case STT_FUNC: 2998 case STT_NOTYPE: 2999 case STT_OBJECT: 3000 if (symp->st_value == 0) 3001 continue; 3002 /* fallthrough */ 3003 case STT_TLS: 3004 if (symp->st_shndx != SHN_UNDEF) 3005 break; 3006 else if (((flags & SYMLOOK_IN_PLT) == 0) && 3007 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3008 break; 3009 /* fallthrough */ 3010 default: 3011 continue; 3012 } 3013 if (name[0] != strp[0] || strcmp(name, strp) != 0) 3014 continue; 3015 3016 if (ventry == NULL) { 3017 if (obj->versyms != NULL) { 3018 verndx = VER_NDX(obj->versyms[symnum]); 3019 if (verndx > obj->vernum) { 3020 _rtld_error("%s: symbol %s references wrong version %d", 3021 obj->path, obj->strtab + symnum, verndx); 3022 continue; 3023 } 3024 /* 3025 * If we are not called from dlsym (i.e. this is a normal 3026 * relocation from unversioned binary), accept the symbol 3027 * immediately if it happens to have first version after 3028 * this shared object became versioned. Otherwise, if 3029 * symbol is versioned and not hidden, remember it. If it 3030 * is the only symbol with this name exported by the 3031 * shared object, it will be returned as a match at the 3032 * end of the function. If symbol is global (verndx < 2) 3033 * accept it unconditionally. 3034 */ 3035 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) 3036 return symp; 3037 else if (verndx >= VER_NDX_GIVEN) { 3038 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3039 if (vsymp == NULL) 3040 vsymp = symp; 3041 vcount ++; 3042 } 3043 continue; 3044 } 3045 } 3046 return symp; 3047 } else { 3048 if (obj->versyms == NULL) { 3049 if (object_match_name(obj, ventry->name)) { 3050 _rtld_error("%s: object %s should provide version %s for " 3051 "symbol %s", obj_rtld.path, obj->path, ventry->name, 3052 obj->strtab + symnum); 3053 continue; 3054 } 3055 } else { 3056 verndx = VER_NDX(obj->versyms[symnum]); 3057 if (verndx > obj->vernum) { 3058 _rtld_error("%s: symbol %s references wrong version %d", 3059 obj->path, obj->strtab + symnum, verndx); 3060 continue; 3061 } 3062 if (obj->vertab[verndx].hash != ventry->hash || 3063 strcmp(obj->vertab[verndx].name, ventry->name)) { 3064 /* 3065 * Version does not match. Look if this is a global symbol 3066 * and if it is not hidden. If global symbol (verndx < 2) 3067 * is available, use it. Do not return symbol if we are 3068 * called by dlvsym, because dlvsym looks for a specific 3069 * version and default one is not what dlvsym wants. 3070 */ 3071 if ((flags & SYMLOOK_DLSYM) || 3072 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3073 (verndx >= VER_NDX_GIVEN)) 3074 continue; 3075 } 3076 } 3077 return symp; 3078 } 3079 } 3080 return (vcount == 1) ? vsymp : NULL; 3081 } 3082 3083 static void 3084 trace_loaded_objects(Obj_Entry *obj) 3085 { 3086 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3087 int c; 3088 3089 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3090 main_local = ""; 3091 3092 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3093 fmt1 = "\t%o => %p (%x)\n"; 3094 3095 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3096 fmt2 = "\t%o (%x)\n"; 3097 3098 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 3099 3100 for (; obj; obj = obj->next) { 3101 Needed_Entry *needed; 3102 char *name, *path; 3103 bool is_lib; 3104 3105 if (list_containers && obj->needed != NULL) 3106 printf("%s:\n", obj->path); 3107 for (needed = obj->needed; needed; needed = needed->next) { 3108 if (needed->obj != NULL) { 3109 if (needed->obj->traced && !list_containers) 3110 continue; 3111 needed->obj->traced = true; 3112 path = needed->obj->path; 3113 } else 3114 path = "not found"; 3115 3116 name = (char *)obj->strtab + needed->name; 3117 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3118 3119 fmt = is_lib ? fmt1 : fmt2; 3120 while ((c = *fmt++) != '\0') { 3121 switch (c) { 3122 default: 3123 putchar(c); 3124 continue; 3125 case '\\': 3126 switch (c = *fmt) { 3127 case '\0': 3128 continue; 3129 case 'n': 3130 putchar('\n'); 3131 break; 3132 case 't': 3133 putchar('\t'); 3134 break; 3135 } 3136 break; 3137 case '%': 3138 switch (c = *fmt) { 3139 case '\0': 3140 continue; 3141 case '%': 3142 default: 3143 putchar(c); 3144 break; 3145 case 'A': 3146 printf("%s", main_local); 3147 break; 3148 case 'a': 3149 printf("%s", obj_main->path); 3150 break; 3151 case 'o': 3152 printf("%s", name); 3153 break; 3154 case 'p': 3155 printf("%s", path); 3156 break; 3157 case 'x': 3158 printf("%p", needed->obj ? needed->obj->mapbase : 0); 3159 break; 3160 } 3161 break; 3162 } 3163 ++fmt; 3164 } 3165 } 3166 } 3167 } 3168 3169 /* 3170 * Unload a dlopened object and its dependencies from memory and from 3171 * our data structures. It is assumed that the DAG rooted in the 3172 * object has already been unreferenced, and that the object has a 3173 * reference count of 0. 3174 */ 3175 static void 3176 unload_object(Obj_Entry *root) 3177 { 3178 Obj_Entry *obj; 3179 Obj_Entry **linkp; 3180 3181 assert(root->refcount == 0); 3182 3183 /* 3184 * Pass over the DAG removing unreferenced objects from 3185 * appropriate lists. 3186 */ 3187 unlink_object(root); 3188 3189 /* Unmap all objects that are no longer referenced. */ 3190 linkp = &obj_list->next; 3191 while ((obj = *linkp) != NULL) { 3192 if (obj->refcount == 0) { 3193 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3194 obj->path); 3195 dbg("unloading \"%s\"", obj->path); 3196 munmap(obj->mapbase, obj->mapsize); 3197 linkmap_delete(obj); 3198 *linkp = obj->next; 3199 obj_count--; 3200 obj_free(obj); 3201 } else 3202 linkp = &obj->next; 3203 } 3204 obj_tail = linkp; 3205 } 3206 3207 static void 3208 unlink_object(Obj_Entry *root) 3209 { 3210 Objlist_Entry *elm; 3211 3212 if (root->refcount == 0) { 3213 /* Remove the object from the RTLD_GLOBAL list. */ 3214 objlist_remove(&list_global, root); 3215 3216 /* Remove the object from all objects' DAG lists. */ 3217 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3218 objlist_remove(&elm->obj->dldags, root); 3219 if (elm->obj != root) 3220 unlink_object(elm->obj); 3221 } 3222 } 3223 } 3224 3225 static void 3226 ref_dag(Obj_Entry *root) 3227 { 3228 Objlist_Entry *elm; 3229 3230 assert(root->dag_inited); 3231 STAILQ_FOREACH(elm, &root->dagmembers, link) 3232 elm->obj->refcount++; 3233 } 3234 3235 static void 3236 unref_dag(Obj_Entry *root) 3237 { 3238 Objlist_Entry *elm; 3239 3240 assert(root->dag_inited); 3241 STAILQ_FOREACH(elm, &root->dagmembers, link) 3242 elm->obj->refcount--; 3243 } 3244 3245 /* 3246 * Common code for MD __tls_get_addr(). 3247 */ 3248 void * 3249 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3250 { 3251 Elf_Addr* dtv = *dtvp; 3252 RtldLockState lockstate; 3253 3254 /* Check dtv generation in case new modules have arrived */ 3255 if (dtv[0] != tls_dtv_generation) { 3256 Elf_Addr* newdtv; 3257 int to_copy; 3258 3259 wlock_acquire(rtld_bind_lock, &lockstate); 3260 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3261 to_copy = dtv[1]; 3262 if (to_copy > tls_max_index) 3263 to_copy = tls_max_index; 3264 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3265 newdtv[0] = tls_dtv_generation; 3266 newdtv[1] = tls_max_index; 3267 free(dtv); 3268 lock_release(rtld_bind_lock, &lockstate); 3269 *dtvp = newdtv; 3270 } 3271 3272 /* Dynamically allocate module TLS if necessary */ 3273 if (!dtv[index + 1]) { 3274 /* Signal safe, wlock will block out signals. */ 3275 wlock_acquire(rtld_bind_lock, &lockstate); 3276 if (!dtv[index + 1]) 3277 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3278 lock_release(rtld_bind_lock, &lockstate); 3279 } 3280 return (void*) (dtv[index + 1] + offset); 3281 } 3282 3283 #if defined(RTLD_STATIC_TLS_VARIANT_II) 3284 3285 /* 3286 * Allocate the static TLS area. Return a pointer to the TCB. The 3287 * static area is based on negative offsets relative to the tcb. 3288 * 3289 * The TCB contains an errno pointer for the system call layer, but because 3290 * we are the RTLD we really have no idea how the caller was compiled so 3291 * the information has to be passed in. errno can either be: 3292 * 3293 * type 0 errno is a simple non-TLS global pointer. 3294 * (special case for e.g. libc_rtld) 3295 * type 1 errno accessed by GOT entry (dynamically linked programs) 3296 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 3297 */ 3298 struct tls_tcb * 3299 allocate_tls(Obj_Entry *objs) 3300 { 3301 Obj_Entry *obj; 3302 size_t data_size; 3303 size_t dtv_size; 3304 struct tls_tcb *tcb; 3305 Elf_Addr *dtv; 3306 Elf_Addr addr; 3307 3308 /* 3309 * Allocate the new TCB. static TLS storage is placed just before the 3310 * TCB to support the %gs:OFFSET (negative offset) model. 3311 */ 3312 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 3313 ~RTLD_STATIC_TLS_ALIGN_MASK; 3314 tcb = malloc(data_size + sizeof(*tcb)); 3315 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 3316 3317 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 3318 dtv = malloc(dtv_size); 3319 bzero(dtv, dtv_size); 3320 3321 #ifdef RTLD_TCB_HAS_SELF_POINTER 3322 tcb->tcb_self = tcb; 3323 #endif 3324 tcb->tcb_dtv = dtv; 3325 tcb->tcb_pthread = NULL; 3326 3327 dtv[0] = tls_dtv_generation; 3328 dtv[1] = tls_max_index; 3329 3330 for (obj = objs; obj; obj = obj->next) { 3331 if (obj->tlsoffset) { 3332 addr = (Elf_Addr)tcb - obj->tlsoffset; 3333 memset((void *)(addr + obj->tlsinitsize), 3334 0, obj->tlssize - obj->tlsinitsize); 3335 if (obj->tlsinit) 3336 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3337 dtv[obj->tlsindex + 1] = addr; 3338 } 3339 } 3340 return(tcb); 3341 } 3342 3343 void 3344 free_tls(struct tls_tcb *tcb) 3345 { 3346 Elf_Addr *dtv; 3347 int dtv_size, i; 3348 Elf_Addr tls_start, tls_end; 3349 size_t data_size; 3350 3351 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 3352 ~RTLD_STATIC_TLS_ALIGN_MASK; 3353 3354 dtv = tcb->tcb_dtv; 3355 dtv_size = dtv[1]; 3356 tls_end = (Elf_Addr)tcb; 3357 tls_start = (Elf_Addr)tcb - data_size; 3358 for (i = 0; i < dtv_size; i++) { 3359 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 3360 free((void *)dtv[i+2]); 3361 } 3362 } 3363 3364 free((void*) tls_start); 3365 } 3366 3367 #else 3368 #error "Unsupported TLS layout" 3369 #endif 3370 3371 /* 3372 * Allocate TLS block for module with given index. 3373 */ 3374 void * 3375 allocate_module_tls(int index) 3376 { 3377 Obj_Entry* obj; 3378 char* p; 3379 3380 for (obj = obj_list; obj; obj = obj->next) { 3381 if (obj->tlsindex == index) 3382 break; 3383 } 3384 if (!obj) { 3385 _rtld_error("Can't find module with TLS index %d", index); 3386 die(); 3387 } 3388 3389 p = malloc(obj->tlssize); 3390 if (p == NULL) { 3391 _rtld_error("Cannot allocate TLS block for index %d", index); 3392 die(); 3393 } 3394 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3395 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3396 3397 return p; 3398 } 3399 3400 bool 3401 allocate_tls_offset(Obj_Entry *obj) 3402 { 3403 size_t off; 3404 3405 if (obj->tls_done) 3406 return true; 3407 3408 if (obj->tlssize == 0) { 3409 obj->tls_done = true; 3410 return true; 3411 } 3412 3413 if (obj->tlsindex == 1) 3414 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3415 else 3416 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3417 obj->tlssize, obj->tlsalign); 3418 3419 /* 3420 * If we have already fixed the size of the static TLS block, we 3421 * must stay within that size. When allocating the static TLS, we 3422 * leave a small amount of space spare to be used for dynamically 3423 * loading modules which use static TLS. 3424 */ 3425 if (tls_static_space) { 3426 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3427 return false; 3428 } 3429 3430 tls_last_offset = obj->tlsoffset = off; 3431 tls_last_size = obj->tlssize; 3432 obj->tls_done = true; 3433 3434 return true; 3435 } 3436 3437 void 3438 free_tls_offset(Obj_Entry *obj) 3439 { 3440 #ifdef RTLD_STATIC_TLS_VARIANT_II 3441 /* 3442 * If we were the last thing to allocate out of the static TLS 3443 * block, we give our space back to the 'allocator'. This is a 3444 * simplistic workaround to allow libGL.so.1 to be loaded and 3445 * unloaded multiple times. We only handle the Variant II 3446 * mechanism for now - this really needs a proper allocator. 3447 */ 3448 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3449 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3450 tls_last_offset -= obj->tlssize; 3451 tls_last_size = 0; 3452 } 3453 #endif 3454 } 3455 3456 struct tls_tcb * 3457 _rtld_allocate_tls(void) 3458 { 3459 struct tls_tcb *new_tcb; 3460 RtldLockState lockstate; 3461 3462 wlock_acquire(rtld_bind_lock, &lockstate); 3463 new_tcb = allocate_tls(obj_list); 3464 lock_release(rtld_bind_lock, &lockstate); 3465 return (new_tcb); 3466 } 3467 3468 void 3469 _rtld_free_tls(struct tls_tcb *tcb) 3470 { 3471 RtldLockState lockstate; 3472 3473 wlock_acquire(rtld_bind_lock, &lockstate); 3474 free_tls(tcb); 3475 lock_release(rtld_bind_lock, &lockstate); 3476 } 3477 3478 static void 3479 object_add_name(Obj_Entry *obj, const char *name) 3480 { 3481 Name_Entry *entry; 3482 size_t len; 3483 3484 len = strlen(name); 3485 entry = malloc(sizeof(Name_Entry) + len); 3486 3487 if (entry != NULL) { 3488 strcpy(entry->name, name); 3489 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3490 } 3491 } 3492 3493 static int 3494 object_match_name(const Obj_Entry *obj, const char *name) 3495 { 3496 Name_Entry *entry; 3497 3498 STAILQ_FOREACH(entry, &obj->names, link) { 3499 if (strcmp(name, entry->name) == 0) 3500 return (1); 3501 } 3502 return (0); 3503 } 3504 3505 static Obj_Entry * 3506 locate_dependency(const Obj_Entry *obj, const char *name) 3507 { 3508 const Objlist_Entry *entry; 3509 const Needed_Entry *needed; 3510 3511 STAILQ_FOREACH(entry, &list_main, link) { 3512 if (object_match_name(entry->obj, name)) 3513 return entry->obj; 3514 } 3515 3516 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3517 if (strcmp(obj->strtab + needed->name, name) == 0 || 3518 (needed->obj != NULL && object_match_name(needed->obj, name))) { 3519 /* 3520 * If there is DT_NEEDED for the name we are looking for, 3521 * we are all set. Note that object might not be found if 3522 * dependency was not loaded yet, so the function can 3523 * return NULL here. This is expected and handled 3524 * properly by the caller. 3525 */ 3526 return (needed->obj); 3527 } 3528 } 3529 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3530 obj->path, name); 3531 die(); 3532 } 3533 3534 static int 3535 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3536 const Elf_Vernaux *vna) 3537 { 3538 const Elf_Verdef *vd; 3539 const char *vername; 3540 3541 vername = refobj->strtab + vna->vna_name; 3542 vd = depobj->verdef; 3543 if (vd == NULL) { 3544 _rtld_error("%s: version %s required by %s not defined", 3545 depobj->path, vername, refobj->path); 3546 return (-1); 3547 } 3548 for (;;) { 3549 if (vd->vd_version != VER_DEF_CURRENT) { 3550 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3551 depobj->path, vd->vd_version); 3552 return (-1); 3553 } 3554 if (vna->vna_hash == vd->vd_hash) { 3555 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3556 ((char *)vd + vd->vd_aux); 3557 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3558 return (0); 3559 } 3560 if (vd->vd_next == 0) 3561 break; 3562 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3563 } 3564 if (vna->vna_flags & VER_FLG_WEAK) 3565 return (0); 3566 _rtld_error("%s: version %s required by %s not found", 3567 depobj->path, vername, refobj->path); 3568 return (-1); 3569 } 3570 3571 static int 3572 rtld_verify_object_versions(Obj_Entry *obj) 3573 { 3574 const Elf_Verneed *vn; 3575 const Elf_Verdef *vd; 3576 const Elf_Verdaux *vda; 3577 const Elf_Vernaux *vna; 3578 const Obj_Entry *depobj; 3579 int maxvernum, vernum; 3580 3581 maxvernum = 0; 3582 /* 3583 * Walk over defined and required version records and figure out 3584 * max index used by any of them. Do very basic sanity checking 3585 * while there. 3586 */ 3587 vn = obj->verneed; 3588 while (vn != NULL) { 3589 if (vn->vn_version != VER_NEED_CURRENT) { 3590 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3591 obj->path, vn->vn_version); 3592 return (-1); 3593 } 3594 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3595 for (;;) { 3596 vernum = VER_NEED_IDX(vna->vna_other); 3597 if (vernum > maxvernum) 3598 maxvernum = vernum; 3599 if (vna->vna_next == 0) 3600 break; 3601 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3602 } 3603 if (vn->vn_next == 0) 3604 break; 3605 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3606 } 3607 3608 vd = obj->verdef; 3609 while (vd != NULL) { 3610 if (vd->vd_version != VER_DEF_CURRENT) { 3611 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3612 obj->path, vd->vd_version); 3613 return (-1); 3614 } 3615 vernum = VER_DEF_IDX(vd->vd_ndx); 3616 if (vernum > maxvernum) 3617 maxvernum = vernum; 3618 if (vd->vd_next == 0) 3619 break; 3620 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3621 } 3622 3623 if (maxvernum == 0) 3624 return (0); 3625 3626 /* 3627 * Store version information in array indexable by version index. 3628 * Verify that object version requirements are satisfied along the 3629 * way. 3630 */ 3631 obj->vernum = maxvernum + 1; 3632 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3633 3634 vd = obj->verdef; 3635 while (vd != NULL) { 3636 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3637 vernum = VER_DEF_IDX(vd->vd_ndx); 3638 assert(vernum <= maxvernum); 3639 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3640 obj->vertab[vernum].hash = vd->vd_hash; 3641 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3642 obj->vertab[vernum].file = NULL; 3643 obj->vertab[vernum].flags = 0; 3644 } 3645 if (vd->vd_next == 0) 3646 break; 3647 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3648 } 3649 3650 vn = obj->verneed; 3651 while (vn != NULL) { 3652 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3653 if (depobj == NULL) 3654 return (-1); 3655 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3656 for (;;) { 3657 if (check_object_provided_version(obj, depobj, vna)) 3658 return (-1); 3659 vernum = VER_NEED_IDX(vna->vna_other); 3660 assert(vernum <= maxvernum); 3661 obj->vertab[vernum].hash = vna->vna_hash; 3662 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3663 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3664 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3665 VER_INFO_HIDDEN : 0; 3666 if (vna->vna_next == 0) 3667 break; 3668 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3669 } 3670 if (vn->vn_next == 0) 3671 break; 3672 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3673 } 3674 return 0; 3675 } 3676 3677 static int 3678 rtld_verify_versions(const Objlist *objlist) 3679 { 3680 Objlist_Entry *entry; 3681 int rc; 3682 3683 rc = 0; 3684 STAILQ_FOREACH(entry, objlist, link) { 3685 /* 3686 * Skip dummy objects or objects that have their version requirements 3687 * already checked. 3688 */ 3689 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3690 continue; 3691 if (rtld_verify_object_versions(entry->obj) == -1) { 3692 rc = -1; 3693 if (ld_tracing == NULL) 3694 break; 3695 } 3696 } 3697 if (rc == 0 || ld_tracing != NULL) 3698 rc = rtld_verify_object_versions(&obj_rtld); 3699 return rc; 3700 } 3701 3702 const Ver_Entry * 3703 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3704 { 3705 Elf_Versym vernum; 3706 3707 if (obj->vertab) { 3708 vernum = VER_NDX(obj->versyms[symnum]); 3709 if (vernum >= obj->vernum) { 3710 _rtld_error("%s: symbol %s has wrong verneed value %d", 3711 obj->path, obj->strtab + symnum, vernum); 3712 } else if (obj->vertab[vernum].hash != 0) { 3713 return &obj->vertab[vernum]; 3714 } 3715 } 3716 return NULL; 3717 } 3718 3719 /* 3720 * No unresolved symbols for rtld. 3721 */ 3722 void 3723 __pthread_cxa_finalize(struct dl_phdr_info *a) 3724 { 3725 } 3726