1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mount.h> 42 #include <sys/mman.h> 43 #include <sys/stat.h> 44 #include <sys/sysctl.h> 45 #include <sys/uio.h> 46 #include <sys/utsname.h> 47 #include <sys/ktrace.h> 48 #include <sys/resident.h> 49 #include <sys/tls.h> 50 51 #include <machine/tls.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "rtld_printf.h" 67 68 #define PATH_RTLD "/usr/libexec/ld-elf.so.2" 69 #define LD_ARY_CACHE 16 70 71 /* Types. */ 72 typedef void (*func_ptr_type)(); 73 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 74 75 /* 76 * Function declarations. 77 */ 78 static const char *_getenv_ld(const char *id); 79 static void die(void) __dead2; 80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 81 const Elf_Dyn **); 82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 83 static void digest_dynamic(Obj_Entry *, int); 84 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 85 static Obj_Entry *dlcheck(void *); 86 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj, 87 int lo_flags, int mode); 88 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 89 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 90 static bool donelist_check(DoneList *, const Obj_Entry *); 91 static void errmsg_restore(char *); 92 static char *errmsg_save(void); 93 static void *fill_search_info(const char *, size_t, void *); 94 static char *find_library(const char *, const Obj_Entry *); 95 static const char *gethints(void); 96 static void init_dag(Obj_Entry *); 97 static void init_rtld(caddr_t, Elf_Auxinfo **); 98 static void initlist_add_neededs(Needed_Entry *, Objlist *); 99 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 100 static bool is_exported(const Elf_Sym *); 101 static void linkmap_add(Obj_Entry *); 102 static void linkmap_delete(Obj_Entry *); 103 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 104 static void unload_filtees(Obj_Entry *); 105 static int load_needed_objects(Obj_Entry *, int); 106 static int load_preload_objects(void); 107 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 108 static void map_stacks_exec(RtldLockState *); 109 static Obj_Entry *obj_from_addr(const void *); 110 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 111 static void objlist_call_init(Objlist *, RtldLockState *); 112 static void objlist_clear(Objlist *); 113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114 static void objlist_init(Objlist *); 115 static void objlist_push_head(Objlist *, Obj_Entry *); 116 static void objlist_push_tail(Objlist *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *); 120 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 121 RtldLockState *lockstate); 122 static int rtld_dirname(const char *, char *); 123 static int rtld_dirname_abs(const char *, char *); 124 static void rtld_exit(void); 125 static char *search_library_path(const char *, const char *); 126 static const void **get_program_var_addr(const char *, RtldLockState *); 127 static void set_program_var(const char *, const void *); 128 static int symlook_default(SymLook *, const Obj_Entry *refobj); 129 static int symlook_global(SymLook *, DoneList *); 130 static void symlook_init_from_req(SymLook *, const SymLook *); 131 static int symlook_list(SymLook *, const Objlist *, DoneList *); 132 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 133 static int symlook_obj1(SymLook *, const Obj_Entry *); 134 static void trace_loaded_objects(Obj_Entry *); 135 static void unlink_object(Obj_Entry *); 136 static void unload_object(Obj_Entry *); 137 static void unref_dag(Obj_Entry *); 138 static void ref_dag(Obj_Entry *); 139 static int origin_subst_one(char **, const char *, const char *, 140 const char *, char *); 141 static char *origin_subst(const char *, const char *); 142 static int rtld_verify_versions(const Objlist *); 143 static int rtld_verify_object_versions(Obj_Entry *); 144 static void object_add_name(Obj_Entry *, const char *); 145 static int object_match_name(const Obj_Entry *, const char *); 146 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 147 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 148 struct dl_phdr_info *phdr_info); 149 150 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 151 152 /* 153 * Data declarations. 154 */ 155 static char *error_message; /* Message for dlerror(), or NULL */ 156 struct r_debug r_debug; /* for GDB; */ 157 static bool libmap_disable; /* Disable libmap */ 158 static bool ld_loadfltr; /* Immediate filters processing */ 159 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 160 static bool trust; /* False for setuid and setgid programs */ 161 static bool dangerous_ld_env; /* True if environment variables have been 162 used to affect the libraries loaded */ 163 static const char *ld_bind_now; /* Environment variable for immediate binding */ 164 static const char *ld_debug; /* Environment variable for debugging */ 165 static const char *ld_library_path; /* Environment variable for search path */ 166 static char *ld_preload; /* Environment variable for libraries to 167 load first */ 168 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 169 static const char *ld_tracing; /* Called from ldd to print libs */ 170 static const char *ld_utrace; /* Use utrace() to log events. */ 171 static int (*rtld_functrace)( /* Optional function call tracing hook */ 172 const char *caller_obj, 173 const char *callee_obj, 174 const char *callee_func, 175 void *stack); 176 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */ 177 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 178 static Obj_Entry **obj_tail; /* Link field of last object in list */ 179 static Obj_Entry **preload_tail; 180 static Obj_Entry *obj_main; /* The main program shared object */ 181 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 182 static unsigned int obj_count; /* Number of objects in obj_list */ 183 static unsigned int obj_loads; /* Number of objects in obj_list */ 184 185 static int ld_resident; /* Non-zero if resident */ 186 static const char *ld_ary[LD_ARY_CACHE]; 187 static int ld_index; 188 static Objlist initlist; 189 190 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 191 STAILQ_HEAD_INITIALIZER(list_global); 192 static Objlist list_main = /* Objects loaded at program startup */ 193 STAILQ_HEAD_INITIALIZER(list_main); 194 static Objlist list_fini = /* Objects needing fini() calls */ 195 STAILQ_HEAD_INITIALIZER(list_fini); 196 197 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 198 199 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 200 201 extern Elf_Dyn _DYNAMIC; 202 #pragma weak _DYNAMIC 203 #ifndef RTLD_IS_DYNAMIC 204 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 205 #endif 206 207 #ifdef ENABLE_OSRELDATE 208 int osreldate; 209 #endif 210 211 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 212 static int max_stack_flags; 213 214 /* 215 * These are the functions the dynamic linker exports to application 216 * programs. They are the only symbols the dynamic linker is willing 217 * to export from itself. 218 */ 219 static func_ptr_type exports[] = { 220 (func_ptr_type) &_rtld_error, 221 (func_ptr_type) &dlclose, 222 (func_ptr_type) &dlerror, 223 (func_ptr_type) &dlopen, 224 (func_ptr_type) &dlfunc, 225 (func_ptr_type) &dlsym, 226 (func_ptr_type) &dlvsym, 227 (func_ptr_type) &dladdr, 228 (func_ptr_type) &dlinfo, 229 (func_ptr_type) &dl_iterate_phdr, 230 #ifdef __i386__ 231 (func_ptr_type) &___tls_get_addr, 232 #endif 233 (func_ptr_type) &__tls_get_addr, 234 (func_ptr_type) &__tls_get_addr_tcb, 235 (func_ptr_type) &_rtld_allocate_tls, 236 (func_ptr_type) &_rtld_free_tls, 237 (func_ptr_type) &_rtld_call_init, 238 (func_ptr_type) &_rtld_thread_init, 239 (func_ptr_type) &_rtld_addr_phdr, 240 (func_ptr_type) &_rtld_get_stack_prot, 241 NULL 242 }; 243 244 /* 245 * Global declarations normally provided by crt1. The dynamic linker is 246 * not built with crt1, so we have to provide them ourselves. 247 */ 248 char *__progname; 249 char **environ; 250 251 /* 252 * Globals to control TLS allocation. 253 */ 254 size_t tls_last_offset; /* Static TLS offset of last module */ 255 size_t tls_last_size; /* Static TLS size of last module */ 256 size_t tls_static_space; /* Static TLS space allocated */ 257 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 258 int tls_max_index = 1; /* Largest module index allocated */ 259 260 /* 261 * Fill in a DoneList with an allocation large enough to hold all of 262 * the currently-loaded objects. Keep this as a macro since it calls 263 * alloca and we want that to occur within the scope of the caller. 264 */ 265 #define donelist_init(dlp) \ 266 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 267 assert((dlp)->objs != NULL), \ 268 (dlp)->num_alloc = obj_count, \ 269 (dlp)->num_used = 0) 270 271 #define UTRACE_DLOPEN_START 1 272 #define UTRACE_DLOPEN_STOP 2 273 #define UTRACE_DLCLOSE_START 3 274 #define UTRACE_DLCLOSE_STOP 4 275 #define UTRACE_LOAD_OBJECT 5 276 #define UTRACE_UNLOAD_OBJECT 6 277 #define UTRACE_ADD_RUNDEP 7 278 #define UTRACE_PRELOAD_FINISHED 8 279 #define UTRACE_INIT_CALL 9 280 #define UTRACE_FINI_CALL 10 281 282 struct utrace_rtld { 283 char sig[4]; /* 'RTLD' */ 284 int event; 285 void *handle; 286 void *mapbase; /* Used for 'parent' and 'init/fini' */ 287 size_t mapsize; 288 int refcnt; /* Used for 'mode' */ 289 char name[MAXPATHLEN]; 290 }; 291 292 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 293 if (ld_utrace != NULL) \ 294 ld_utrace_log(e, h, mb, ms, r, n); \ 295 } while (0) 296 297 static void 298 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 299 int refcnt, const char *name) 300 { 301 struct utrace_rtld ut; 302 303 ut.sig[0] = 'R'; 304 ut.sig[1] = 'T'; 305 ut.sig[2] = 'L'; 306 ut.sig[3] = 'D'; 307 ut.event = event; 308 ut.handle = handle; 309 ut.mapbase = mapbase; 310 ut.mapsize = mapsize; 311 ut.refcnt = refcnt; 312 bzero(ut.name, sizeof(ut.name)); 313 if (name) 314 strlcpy(ut.name, name, sizeof(ut.name)); 315 utrace(&ut, sizeof(ut)); 316 } 317 318 /* 319 * Main entry point for dynamic linking. The first argument is the 320 * stack pointer. The stack is expected to be laid out as described 321 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 322 * Specifically, the stack pointer points to a word containing 323 * ARGC. Following that in the stack is a null-terminated sequence 324 * of pointers to argument strings. Then comes a null-terminated 325 * sequence of pointers to environment strings. Finally, there is a 326 * sequence of "auxiliary vector" entries. 327 * 328 * The second argument points to a place to store the dynamic linker's 329 * exit procedure pointer and the third to a place to store the main 330 * program's object. 331 * 332 * The return value is the main program's entry point. 333 */ 334 func_ptr_type 335 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 336 { 337 Elf_Auxinfo *aux_info[AT_COUNT]; 338 int i; 339 int argc; 340 char **argv; 341 char **env; 342 Elf_Auxinfo *aux; 343 Elf_Auxinfo *auxp; 344 const char *argv0; 345 Objlist_Entry *entry; 346 Obj_Entry *obj; 347 348 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 349 Obj_Entry **preload_tail; 350 Objlist initlist; 351 from global to here. It will break the DWARF2 unwind scheme. 352 The system compilers were unaffected, but not gcc 4.6 353 */ 354 355 /* 356 * On entry, the dynamic linker itself has not been relocated yet. 357 * Be very careful not to reference any global data until after 358 * init_rtld has returned. It is OK to reference file-scope statics 359 * and string constants, and to call static and global functions. 360 */ 361 362 /* Find the auxiliary vector on the stack. */ 363 argc = *sp++; 364 argv = (char **) sp; 365 sp += argc + 1; /* Skip over arguments and NULL terminator */ 366 env = (char **) sp; 367 368 /* 369 * If we aren't already resident we have to dig out some more info. 370 * Note that auxinfo does not exist when we are resident. 371 * 372 * I'm not sure about the ld_resident check. It seems to read zero 373 * prior to relocation, which is what we want. When running from a 374 * resident copy everything will be relocated so we are definitely 375 * good there. 376 */ 377 if (ld_resident == 0) { 378 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 379 ; 380 aux = (Elf_Auxinfo *) sp; 381 382 /* Digest the auxiliary vector. */ 383 for (i = 0; i < AT_COUNT; i++) 384 aux_info[i] = NULL; 385 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 386 if (auxp->a_type < AT_COUNT) 387 aux_info[auxp->a_type] = auxp; 388 } 389 390 /* Initialize and relocate ourselves. */ 391 assert(aux_info[AT_BASE] != NULL); 392 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 393 } 394 395 ld_index = 0; /* don't use old env cache in case we are resident */ 396 __progname = obj_rtld.path; 397 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 398 environ = env; 399 400 trust = !issetugid(); 401 402 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 403 /* 404 * If the process is tainted, then we un-set the dangerous environment 405 * variables. The process will be marked as tainted until setuid(2) 406 * is called. If any child process calls setuid(2) we do not want any 407 * future processes to honor the potentially un-safe variables. 408 */ 409 if (!trust) { 410 if ( unsetenv("LD_DEBUG") 411 || unsetenv("LD_PRELOAD") 412 || unsetenv("LD_LIBRARY_PATH") 413 || unsetenv("LD_ELF_HINTS_PATH") 414 || unsetenv("LD_LIBMAP") 415 || unsetenv("LD_LIBMAP_DISABLE") 416 || unsetenv("LD_LOADFLTR") 417 ) { 418 _rtld_error("environment corrupt; aborting"); 419 die(); 420 } 421 } 422 ld_debug = _getenv_ld("LD_DEBUG"); 423 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 424 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 425 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 426 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 427 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 428 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL; 429 dangerous_ld_env = (ld_library_path != NULL) 430 || (ld_preload != NULL) 431 || (ld_elf_hints_path != NULL) 432 || ld_loadfltr 433 || (libmap_override != NULL) 434 || libmap_disable 435 ; 436 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 437 ld_utrace = _getenv_ld("LD_UTRACE"); 438 439 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 440 ld_elf_hints_path = _PATH_ELF_HINTS; 441 442 if (ld_debug != NULL && *ld_debug != '\0') 443 debug = 1; 444 dbg("%s is initialized, base address = %p", __progname, 445 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 446 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 447 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 448 449 dbg("initializing thread locks"); 450 lockdflt_init(); 451 452 /* 453 * If we are resident we can skip work that we have already done. 454 * Note that the stack is reset and there is no Elf_Auxinfo 455 * when running from a resident image, and the static globals setup 456 * between here and resident_skip will have already been setup. 457 */ 458 if (ld_resident) 459 goto resident_skip1; 460 461 /* 462 * Load the main program, or process its program header if it is 463 * already loaded. 464 */ 465 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 466 int fd = aux_info[AT_EXECFD]->a_un.a_val; 467 dbg("loading main program"); 468 obj_main = map_object(fd, argv0, NULL); 469 close(fd); 470 if (obj_main == NULL) 471 die(); 472 max_stack_flags = obj->stack_flags; 473 } else { /* Main program already loaded. */ 474 const Elf_Phdr *phdr; 475 int phnum; 476 caddr_t entry; 477 478 dbg("processing main program's program header"); 479 assert(aux_info[AT_PHDR] != NULL); 480 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 481 assert(aux_info[AT_PHNUM] != NULL); 482 phnum = aux_info[AT_PHNUM]->a_un.a_val; 483 assert(aux_info[AT_PHENT] != NULL); 484 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 485 assert(aux_info[AT_ENTRY] != NULL); 486 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 487 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 488 die(); 489 } 490 491 char buf[MAXPATHLEN]; 492 if (aux_info[AT_EXECPATH] != 0) { 493 char *kexecpath; 494 495 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 496 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 497 if (kexecpath[0] == '/') 498 obj_main->path = kexecpath; 499 else if (getcwd(buf, sizeof(buf)) == NULL || 500 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 501 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 502 obj_main->path = xstrdup(argv0); 503 else 504 obj_main->path = xstrdup(buf); 505 } else { 506 char resolved[MAXPATHLEN]; 507 dbg("No AT_EXECPATH"); 508 if (argv0[0] == '/') { 509 if (realpath(argv0, resolved) != NULL) 510 obj_main->path = xstrdup(resolved); 511 else 512 obj_main->path = xstrdup(argv0); 513 } else { 514 if (getcwd(buf, sizeof(buf)) != NULL 515 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 516 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 517 && access(buf, R_OK) == 0 518 && realpath(buf, resolved) != NULL) 519 obj_main->path = xstrdup(resolved); 520 else 521 obj_main->path = xstrdup(argv0); 522 } 523 } 524 dbg("obj_main path %s", obj_main->path); 525 obj_main->mainprog = true; 526 527 if (aux_info[AT_STACKPROT] != NULL && 528 aux_info[AT_STACKPROT]->a_un.a_val != 0) 529 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 530 531 /* 532 * Get the actual dynamic linker pathname from the executable if 533 * possible. (It should always be possible.) That ensures that 534 * gdb will find the right dynamic linker even if a non-standard 535 * one is being used. 536 */ 537 if (obj_main->interp != NULL && 538 strcmp(obj_main->interp, obj_rtld.path) != 0) { 539 free(obj_rtld.path); 540 obj_rtld.path = xstrdup(obj_main->interp); 541 __progname = obj_rtld.path; 542 } 543 544 digest_dynamic(obj_main, 0); 545 546 linkmap_add(obj_main); 547 linkmap_add(&obj_rtld); 548 549 /* Link the main program into the list of objects. */ 550 *obj_tail = obj_main; 551 obj_tail = &obj_main->next; 552 obj_count++; 553 obj_loads++; 554 /* Make sure we don't call the main program's init and fini functions. */ 555 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 556 557 /* Initialize a fake symbol for resolving undefined weak references. */ 558 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 559 sym_zero.st_shndx = SHN_UNDEF; 560 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 561 562 if (!libmap_disable) 563 libmap_disable = (bool)lm_init(libmap_override); 564 565 dbg("loading LD_PRELOAD libraries"); 566 if (load_preload_objects() == -1) 567 die(); 568 preload_tail = obj_tail; 569 570 dbg("loading needed objects"); 571 if (load_needed_objects(obj_main, 0) == -1) 572 die(); 573 574 /* Make a list of all objects loaded at startup. */ 575 for (obj = obj_list; obj != NULL; obj = obj->next) { 576 objlist_push_tail(&list_main, obj); 577 obj->refcount++; 578 } 579 580 dbg("checking for required versions"); 581 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 582 die(); 583 584 resident_skip1: 585 586 if (ld_tracing) { /* We're done */ 587 trace_loaded_objects(obj_main); 588 exit(0); 589 } 590 591 if (ld_resident) /* XXX clean this up! */ 592 goto resident_skip2; 593 594 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 595 dump_relocations(obj_main); 596 exit (0); 597 } 598 599 /* setup TLS for main thread */ 600 dbg("initializing initial thread local storage"); 601 STAILQ_FOREACH(entry, &list_main, link) { 602 /* 603 * Allocate all the initial objects out of the static TLS 604 * block even if they didn't ask for it. 605 */ 606 allocate_tls_offset(entry->obj); 607 } 608 609 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 610 611 /* 612 * Do not try to allocate the TLS here, let libc do it itself. 613 * (crt1 for the program will call _init_tls()) 614 */ 615 616 if (relocate_objects(obj_main, 617 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1) 618 die(); 619 620 dbg("doing copy relocations"); 621 if (do_copy_relocations(obj_main) == -1) 622 die(); 623 624 resident_skip2: 625 626 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 627 if (exec_sys_unregister(-1) < 0) { 628 dbg("exec_sys_unregister failed %d\n", errno); 629 exit(errno); 630 } 631 dbg("exec_sys_unregister success\n"); 632 exit(0); 633 } 634 635 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 636 dump_relocations(obj_main); 637 exit (0); 638 } 639 640 dbg("initializing key program variables"); 641 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 642 set_program_var("environ", env); 643 set_program_var("__elf_aux_vector", aux); 644 645 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 646 extern void resident_start(void); 647 ld_resident = 1; 648 if (exec_sys_register(resident_start) < 0) { 649 dbg("exec_sys_register failed %d\n", errno); 650 exit(errno); 651 } 652 dbg("exec_sys_register success\n"); 653 exit(0); 654 } 655 656 /* Make a list of init functions to call. */ 657 objlist_init(&initlist); 658 initlist_add_objects(obj_list, preload_tail, &initlist); 659 660 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 661 662 map_stacks_exec(NULL); 663 664 dbg("resolving ifuncs"); 665 if (resolve_objects_ifunc(obj_main, 666 ld_bind_now != NULL && *ld_bind_now != '\0', NULL) == -1) 667 die(); 668 669 /* 670 * Do NOT call the initlist here, give libc a chance to set up 671 * the initial TLS segment. crt1 will then call _rtld_call_init(). 672 */ 673 674 dbg("transferring control to program entry point = %p", obj_main->entry); 675 676 /* Return the exit procedure and the program entry point. */ 677 *exit_proc = rtld_exit; 678 *objp = obj_main; 679 return (func_ptr_type) obj_main->entry; 680 } 681 682 /* 683 * Call the initialization list for dynamically loaded libraries. 684 * (called from crt1.c). 685 */ 686 void 687 _rtld_call_init(void) 688 { 689 RtldLockState lockstate; 690 Obj_Entry *obj; 691 692 wlock_acquire(rtld_bind_lock, &lockstate); 693 objlist_call_init(&initlist, &lockstate); 694 objlist_clear(&initlist); 695 dbg("loading filtees"); 696 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 697 if (ld_loadfltr || obj->z_loadfltr) 698 load_filtees(obj, 0, &lockstate); 699 } 700 lock_release(rtld_bind_lock, &lockstate); 701 } 702 703 void * 704 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 705 { 706 void *ptr; 707 Elf_Addr target; 708 709 ptr = (void *)make_function_pointer(def, obj); 710 target = ((Elf_Addr (*)(void))ptr)(); 711 return ((void *)target); 712 } 713 714 Elf_Addr 715 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 716 { 717 const Elf_Rel *rel; 718 const Elf_Sym *def; 719 const Obj_Entry *defobj; 720 Elf_Addr *where; 721 Elf_Addr target; 722 RtldLockState lockstate; 723 724 rlock_acquire(rtld_bind_lock, &lockstate); 725 if (sigsetjmp(lockstate.env, 0) != 0) 726 lock_upgrade(rtld_bind_lock, &lockstate); 727 if (obj->pltrel) 728 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 729 else 730 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 731 732 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 733 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 734 &lockstate); 735 if (def == NULL) 736 die(); 737 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 738 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 739 else 740 target = (Elf_Addr)(defobj->relocbase + def->st_value); 741 742 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 743 defobj->strtab + def->st_name, basename(obj->path), 744 (void *)target, basename(defobj->path)); 745 746 /* 747 * If we have a function call tracing hook, and the 748 * hook would like to keep tracing this one function, 749 * prevent the relocation so we will wind up here 750 * the next time again. 751 * 752 * We don't want to functrace calls from the functracer 753 * to avoid recursive loops. 754 */ 755 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 756 if (rtld_functrace(obj->path, 757 defobj->path, 758 defobj->strtab + def->st_name, 759 stack)) 760 lock_release(rtld_bind_lock, &lockstate); 761 return target; 762 } 763 764 /* 765 * Write the new contents for the jmpslot. Note that depending on 766 * architecture, the value which we need to return back to the 767 * lazy binding trampoline may or may not be the target 768 * address. The value returned from reloc_jmpslot() is the value 769 * that the trampoline needs. 770 */ 771 target = reloc_jmpslot(where, target, defobj, obj, rel); 772 lock_release(rtld_bind_lock, &lockstate); 773 return target; 774 } 775 776 /* 777 * Error reporting function. Use it like printf. If formats the message 778 * into a buffer, and sets things up so that the next call to dlerror() 779 * will return the message. 780 */ 781 void 782 _rtld_error(const char *fmt, ...) 783 { 784 static char buf[512]; 785 va_list ap; 786 787 va_start(ap, fmt); 788 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 789 error_message = buf; 790 va_end(ap); 791 } 792 793 /* 794 * Return a dynamically-allocated copy of the current error message, if any. 795 */ 796 static char * 797 errmsg_save(void) 798 { 799 return error_message == NULL ? NULL : xstrdup(error_message); 800 } 801 802 /* 803 * Restore the current error message from a copy which was previously saved 804 * by errmsg_save(). The copy is freed. 805 */ 806 static void 807 errmsg_restore(char *saved_msg) 808 { 809 if (saved_msg == NULL) 810 error_message = NULL; 811 else { 812 _rtld_error("%s", saved_msg); 813 free(saved_msg); 814 } 815 } 816 817 const char * 818 basename(const char *name) 819 { 820 const char *p = strrchr(name, '/'); 821 return p != NULL ? p + 1 : name; 822 } 823 824 static struct utsname uts; 825 826 static int 827 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 828 char *may_free) 829 { 830 const char *p, *p1; 831 char *res1; 832 int subst_len; 833 int kw_len; 834 835 res1 = *res = NULL; 836 p = real; 837 subst_len = kw_len = 0; 838 for (;;) { 839 p1 = strstr(p, kw); 840 if (p1 != NULL) { 841 if (subst_len == 0) { 842 subst_len = strlen(subst); 843 kw_len = strlen(kw); 844 } 845 if (*res == NULL) { 846 *res = xmalloc(PATH_MAX); 847 res1 = *res; 848 } 849 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 850 _rtld_error("Substitution of %s in %s cannot be performed", 851 kw, real); 852 if (may_free != NULL) 853 free(may_free); 854 free(res); 855 return (false); 856 } 857 memcpy(res1, p, p1 - p); 858 res1 += p1 - p; 859 memcpy(res1, subst, subst_len); 860 res1 += subst_len; 861 p = p1 + kw_len; 862 } else { 863 if (*res == NULL) { 864 if (may_free != NULL) 865 *res = may_free; 866 else 867 *res = xstrdup(real); 868 return (true); 869 } 870 *res1 = '\0'; 871 if (may_free != NULL) 872 free(may_free); 873 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 874 free(res); 875 return (false); 876 } 877 return (true); 878 } 879 } 880 } 881 882 static char * 883 origin_subst(const char *real, const char *origin_path) 884 { 885 char *res1, *res2, *res3, *res4; 886 887 if (uts.sysname[0] == '\0') { 888 if (uname(&uts) != 0) { 889 _rtld_error("utsname failed: %d", errno); 890 return (NULL); 891 } 892 } 893 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 894 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 895 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 896 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 897 return (NULL); 898 return (res4); 899 } 900 901 static void 902 die(void) 903 { 904 const char *msg = dlerror(); 905 906 if (msg == NULL) 907 msg = "Fatal error"; 908 rtld_fdputstr(STDERR_FILENO, msg); 909 _exit(1); 910 } 911 912 /* 913 * Process a shared object's DYNAMIC section, and save the important 914 * information in its Obj_Entry structure. 915 */ 916 static void 917 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 918 const Elf_Dyn **dyn_soname) 919 { 920 const Elf_Dyn *dynp; 921 Needed_Entry **needed_tail = &obj->needed; 922 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 923 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 924 int plttype = DT_REL; 925 926 *dyn_rpath = NULL; 927 *dyn_soname = NULL; 928 929 obj->bind_now = false; 930 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 931 switch (dynp->d_tag) { 932 933 case DT_REL: 934 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 935 break; 936 937 case DT_RELSZ: 938 obj->relsize = dynp->d_un.d_val; 939 break; 940 941 case DT_RELENT: 942 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 943 break; 944 945 case DT_JMPREL: 946 obj->pltrel = (const Elf_Rel *) 947 (obj->relocbase + dynp->d_un.d_ptr); 948 break; 949 950 case DT_PLTRELSZ: 951 obj->pltrelsize = dynp->d_un.d_val; 952 break; 953 954 case DT_RELA: 955 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 956 break; 957 958 case DT_RELASZ: 959 obj->relasize = dynp->d_un.d_val; 960 break; 961 962 case DT_RELAENT: 963 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 964 break; 965 966 case DT_PLTREL: 967 plttype = dynp->d_un.d_val; 968 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 969 break; 970 971 case DT_SYMTAB: 972 obj->symtab = (const Elf_Sym *) 973 (obj->relocbase + dynp->d_un.d_ptr); 974 break; 975 976 case DT_SYMENT: 977 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 978 break; 979 980 case DT_STRTAB: 981 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 982 break; 983 984 case DT_STRSZ: 985 obj->strsize = dynp->d_un.d_val; 986 break; 987 988 case DT_VERNEED: 989 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 990 dynp->d_un.d_val); 991 break; 992 993 case DT_VERNEEDNUM: 994 obj->verneednum = dynp->d_un.d_val; 995 break; 996 997 case DT_VERDEF: 998 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 999 dynp->d_un.d_val); 1000 break; 1001 1002 case DT_VERDEFNUM: 1003 obj->verdefnum = dynp->d_un.d_val; 1004 break; 1005 1006 case DT_VERSYM: 1007 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1008 dynp->d_un.d_val); 1009 break; 1010 1011 case DT_HASH: 1012 { 1013 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 1014 (obj->relocbase + dynp->d_un.d_ptr); 1015 obj->nbuckets = hashtab[0]; 1016 obj->nchains = hashtab[1]; 1017 obj->buckets = hashtab + 2; 1018 obj->chains = obj->buckets + obj->nbuckets; 1019 } 1020 break; 1021 1022 case DT_NEEDED: 1023 if (!obj->rtld) { 1024 Needed_Entry *nep = NEW(Needed_Entry); 1025 nep->name = dynp->d_un.d_val; 1026 nep->obj = NULL; 1027 nep->next = NULL; 1028 1029 *needed_tail = nep; 1030 needed_tail = &nep->next; 1031 } 1032 break; 1033 1034 case DT_FILTER: 1035 if (!obj->rtld) { 1036 Needed_Entry *nep = NEW(Needed_Entry); 1037 nep->name = dynp->d_un.d_val; 1038 nep->obj = NULL; 1039 nep->next = NULL; 1040 1041 *needed_filtees_tail = nep; 1042 needed_filtees_tail = &nep->next; 1043 } 1044 break; 1045 1046 case DT_AUXILIARY: 1047 if (!obj->rtld) { 1048 Needed_Entry *nep = NEW(Needed_Entry); 1049 nep->name = dynp->d_un.d_val; 1050 nep->obj = NULL; 1051 nep->next = NULL; 1052 1053 *needed_aux_filtees_tail = nep; 1054 needed_aux_filtees_tail = &nep->next; 1055 } 1056 break; 1057 1058 case DT_PLTGOT: 1059 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1060 break; 1061 1062 case DT_TEXTREL: 1063 obj->textrel = true; 1064 break; 1065 1066 case DT_SYMBOLIC: 1067 obj->symbolic = true; 1068 break; 1069 1070 case DT_RPATH: 1071 case DT_RUNPATH: /* XXX: process separately */ 1072 /* 1073 * We have to wait until later to process this, because we 1074 * might not have gotten the address of the string table yet. 1075 */ 1076 *dyn_rpath = dynp; 1077 break; 1078 1079 case DT_SONAME: 1080 *dyn_soname = dynp; 1081 break; 1082 1083 case DT_INIT: 1084 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1085 break; 1086 1087 case DT_FINI: 1088 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1089 break; 1090 1091 case DT_DEBUG: 1092 /* XXX - not implemented yet */ 1093 if (!early) 1094 dbg("Filling in DT_DEBUG entry"); 1095 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1096 break; 1097 1098 case DT_FLAGS: 1099 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1100 obj->z_origin = true; 1101 if (dynp->d_un.d_val & DF_SYMBOLIC) 1102 obj->symbolic = true; 1103 if (dynp->d_un.d_val & DF_TEXTREL) 1104 obj->textrel = true; 1105 if (dynp->d_un.d_val & DF_BIND_NOW) 1106 obj->bind_now = true; 1107 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1108 ;*/ 1109 break; 1110 1111 case DT_FLAGS_1: 1112 if (dynp->d_un.d_val & DF_1_NOOPEN) 1113 obj->z_noopen = true; 1114 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1115 obj->z_origin = true; 1116 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1117 XXX ;*/ 1118 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1119 obj->bind_now = true; 1120 if (dynp->d_un.d_val & DF_1_NODELETE) 1121 obj->z_nodelete = true; 1122 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1123 obj->z_loadfltr = true; 1124 break; 1125 1126 default: 1127 if (!early) { 1128 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1129 (long)dynp->d_tag); 1130 } 1131 break; 1132 } 1133 } 1134 1135 obj->traced = false; 1136 1137 if (plttype == DT_RELA) { 1138 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1139 obj->pltrel = NULL; 1140 obj->pltrelasize = obj->pltrelsize; 1141 obj->pltrelsize = 0; 1142 } 1143 } 1144 1145 static void 1146 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1147 const Elf_Dyn *dyn_soname) 1148 { 1149 1150 if (obj->z_origin && obj->origin_path == NULL) { 1151 obj->origin_path = xmalloc(PATH_MAX); 1152 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1153 die(); 1154 } 1155 1156 if (dyn_rpath != NULL) { 1157 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1158 if (obj->z_origin) 1159 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1160 } 1161 1162 if (dyn_soname != NULL) 1163 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1164 } 1165 1166 static void 1167 digest_dynamic(Obj_Entry *obj, int early) 1168 { 1169 const Elf_Dyn *dyn_rpath; 1170 const Elf_Dyn *dyn_soname; 1171 1172 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1173 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1174 } 1175 1176 /* 1177 * Process a shared object's program header. This is used only for the 1178 * main program, when the kernel has already loaded the main program 1179 * into memory before calling the dynamic linker. It creates and 1180 * returns an Obj_Entry structure. 1181 */ 1182 static Obj_Entry * 1183 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1184 { 1185 Obj_Entry *obj; 1186 const Elf_Phdr *phlimit = phdr + phnum; 1187 const Elf_Phdr *ph; 1188 int nsegs = 0; 1189 1190 obj = obj_new(); 1191 for (ph = phdr; ph < phlimit; ph++) { 1192 if (ph->p_type != PT_PHDR) 1193 continue; 1194 1195 obj->phdr = phdr; 1196 obj->phsize = ph->p_memsz; 1197 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1198 break; 1199 } 1200 1201 obj->stack_flags = PF_X | PF_R | PF_W; 1202 1203 for (ph = phdr; ph < phlimit; ph++) { 1204 switch (ph->p_type) { 1205 1206 case PT_INTERP: 1207 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1208 break; 1209 1210 case PT_LOAD: 1211 if (nsegs == 0) { /* First load segment */ 1212 obj->vaddrbase = trunc_page(ph->p_vaddr); 1213 obj->mapbase = obj->vaddrbase + obj->relocbase; 1214 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1215 obj->vaddrbase; 1216 } else { /* Last load segment */ 1217 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1218 obj->vaddrbase; 1219 } 1220 nsegs++; 1221 break; 1222 1223 case PT_DYNAMIC: 1224 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1225 break; 1226 1227 case PT_TLS: 1228 obj->tlsindex = 1; 1229 obj->tlssize = ph->p_memsz; 1230 obj->tlsalign = ph->p_align; 1231 obj->tlsinitsize = ph->p_filesz; 1232 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1233 break; 1234 1235 case PT_GNU_STACK: 1236 obj->stack_flags = ph->p_flags; 1237 break; 1238 1239 case PT_GNU_RELRO: 1240 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1241 obj->relro_size = round_page(ph->p_memsz); 1242 break; 1243 } 1244 } 1245 if (nsegs < 1) { 1246 _rtld_error("%s: too few PT_LOAD segments", path); 1247 return NULL; 1248 } 1249 1250 obj->entry = entry; 1251 return obj; 1252 } 1253 1254 static Obj_Entry * 1255 dlcheck(void *handle) 1256 { 1257 Obj_Entry *obj; 1258 1259 for (obj = obj_list; obj != NULL; obj = obj->next) 1260 if (obj == (Obj_Entry *) handle) 1261 break; 1262 1263 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1264 _rtld_error("Invalid shared object handle %p", handle); 1265 return NULL; 1266 } 1267 return obj; 1268 } 1269 1270 /* 1271 * If the given object is already in the donelist, return true. Otherwise 1272 * add the object to the list and return false. 1273 */ 1274 static bool 1275 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1276 { 1277 unsigned int i; 1278 1279 for (i = 0; i < dlp->num_used; i++) 1280 if (dlp->objs[i] == obj) 1281 return true; 1282 /* 1283 * Our donelist allocation should always be sufficient. But if 1284 * our threads locking isn't working properly, more shared objects 1285 * could have been loaded since we allocated the list. That should 1286 * never happen, but we'll handle it properly just in case it does. 1287 */ 1288 if (dlp->num_used < dlp->num_alloc) 1289 dlp->objs[dlp->num_used++] = obj; 1290 return false; 1291 } 1292 1293 /* 1294 * Hash function for symbol table lookup. Don't even think about changing 1295 * this. It is specified by the System V ABI. 1296 */ 1297 unsigned long 1298 elf_hash(const char *name) 1299 { 1300 const unsigned char *p = (const unsigned char *) name; 1301 unsigned long h = 0; 1302 unsigned long g; 1303 1304 while (*p != '\0') { 1305 h = (h << 4) + *p++; 1306 if ((g = h & 0xf0000000) != 0) 1307 h ^= g >> 24; 1308 h &= ~g; 1309 } 1310 return h; 1311 } 1312 1313 /* 1314 * Find the library with the given name, and return its full pathname. 1315 * The returned string is dynamically allocated. Generates an error 1316 * message and returns NULL if the library cannot be found. 1317 * 1318 * If the second argument is non-NULL, then it refers to an already- 1319 * loaded shared object, whose library search path will be searched. 1320 * 1321 * The search order is: 1322 * LD_LIBRARY_PATH 1323 * rpath in the referencing file 1324 * ldconfig hints 1325 * /usr/lib 1326 */ 1327 static char * 1328 find_library(const char *xname, const Obj_Entry *refobj) 1329 { 1330 char *pathname; 1331 char *name; 1332 1333 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1334 if (xname[0] != '/' && !trust) { 1335 _rtld_error("Absolute pathname required for shared object \"%s\"", 1336 xname); 1337 return NULL; 1338 } 1339 if (refobj != NULL && refobj->z_origin) 1340 return origin_subst(xname, refobj->origin_path); 1341 else 1342 return xstrdup(xname); 1343 } 1344 1345 if (libmap_disable || (refobj == NULL) || 1346 (name = lm_find(refobj->path, xname)) == NULL) 1347 name = (char *)xname; 1348 1349 dbg(" Searching for \"%s\"", name); 1350 1351 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1352 (refobj != NULL && 1353 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1354 (pathname = search_library_path(name, gethints())) != NULL || 1355 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1356 return pathname; 1357 1358 if(refobj != NULL && refobj->path != NULL) { 1359 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1360 name, basename(refobj->path)); 1361 } else { 1362 _rtld_error("Shared object \"%s\" not found", name); 1363 } 1364 return NULL; 1365 } 1366 1367 /* 1368 * Given a symbol number in a referencing object, find the corresponding 1369 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1370 * no definition was found. Returns a pointer to the Obj_Entry of the 1371 * defining object via the reference parameter DEFOBJ_OUT. 1372 */ 1373 const Elf_Sym * 1374 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1375 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1376 RtldLockState *lockstate) 1377 { 1378 const Elf_Sym *ref; 1379 const Elf_Sym *def; 1380 const Obj_Entry *defobj; 1381 SymLook req; 1382 const char *name; 1383 int res; 1384 1385 /* 1386 * If we have already found this symbol, get the information from 1387 * the cache. 1388 */ 1389 if (symnum >= refobj->nchains) 1390 return NULL; /* Bad object */ 1391 if (cache != NULL && cache[symnum].sym != NULL) { 1392 *defobj_out = cache[symnum].obj; 1393 return cache[symnum].sym; 1394 } 1395 1396 ref = refobj->symtab + symnum; 1397 name = refobj->strtab + ref->st_name; 1398 def = NULL; 1399 defobj = NULL; 1400 1401 /* 1402 * We don't have to do a full scale lookup if the symbol is local. 1403 * We know it will bind to the instance in this load module; to 1404 * which we already have a pointer (ie ref). By not doing a lookup, 1405 * we not only improve performance, but it also avoids unresolvable 1406 * symbols when local symbols are not in the hash table. 1407 * 1408 * This might occur for TLS module relocations, which simply use 1409 * symbol 0. 1410 */ 1411 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1412 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1413 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1414 symnum); 1415 } 1416 symlook_init(&req, name); 1417 req.flags = flags; 1418 req.ventry = fetch_ventry(refobj, symnum); 1419 req.lockstate = lockstate; 1420 res = symlook_default(&req, refobj); 1421 if (res == 0) { 1422 def = req.sym_out; 1423 defobj = req.defobj_out; 1424 } 1425 } else { 1426 def = ref; 1427 defobj = refobj; 1428 } 1429 1430 /* 1431 * If we found no definition and the reference is weak, treat the 1432 * symbol as having the value zero. 1433 */ 1434 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1435 def = &sym_zero; 1436 defobj = obj_main; 1437 } 1438 1439 if (def != NULL) { 1440 *defobj_out = defobj; 1441 /* Record the information in the cache to avoid subsequent lookups. */ 1442 if (cache != NULL) { 1443 cache[symnum].sym = def; 1444 cache[symnum].obj = defobj; 1445 } 1446 } else { 1447 if (refobj != &obj_rtld) 1448 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1449 } 1450 return def; 1451 } 1452 1453 /* 1454 * Return the search path from the ldconfig hints file, reading it if 1455 * necessary. Returns NULL if there are problems with the hints file, 1456 * or if the search path there is empty. 1457 */ 1458 static const char * 1459 gethints(void) 1460 { 1461 static char *hints; 1462 1463 if (hints == NULL) { 1464 int fd; 1465 struct elfhints_hdr hdr; 1466 char *p; 1467 1468 /* Keep from trying again in case the hints file is bad. */ 1469 hints = ""; 1470 1471 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1472 return NULL; 1473 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1474 hdr.magic != ELFHINTS_MAGIC || 1475 hdr.version != 1) { 1476 close(fd); 1477 return NULL; 1478 } 1479 p = xmalloc(hdr.dirlistlen + 1); 1480 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1481 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1482 free(p); 1483 close(fd); 1484 return NULL; 1485 } 1486 hints = p; 1487 close(fd); 1488 } 1489 return hints[0] != '\0' ? hints : NULL; 1490 } 1491 1492 static void 1493 init_dag(Obj_Entry *root) 1494 { 1495 const Needed_Entry *needed; 1496 const Objlist_Entry *elm; 1497 DoneList donelist; 1498 1499 if (root->dag_inited) 1500 return; 1501 donelist_init(&donelist); 1502 1503 /* Root object belongs to own DAG. */ 1504 objlist_push_tail(&root->dldags, root); 1505 objlist_push_tail(&root->dagmembers, root); 1506 donelist_check(&donelist, root); 1507 1508 /* 1509 * Add dependencies of root object to DAG in breadth order 1510 * by exploiting the fact that each new object get added 1511 * to the tail of the dagmembers list. 1512 */ 1513 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1514 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1515 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1516 continue; 1517 objlist_push_tail(&needed->obj->dldags, root); 1518 objlist_push_tail(&root->dagmembers, needed->obj); 1519 } 1520 } 1521 root->dag_inited = true; 1522 } 1523 1524 /* 1525 * Initialize the dynamic linker. The argument is the address at which 1526 * the dynamic linker has been mapped into memory. The primary task of 1527 * this function is to relocate the dynamic linker. 1528 */ 1529 static void 1530 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1531 { 1532 Obj_Entry objtmp; /* Temporary rtld object */ 1533 const Elf_Dyn *dyn_rpath; 1534 const Elf_Dyn *dyn_soname; 1535 1536 /* 1537 * Conjure up an Obj_Entry structure for the dynamic linker. 1538 * 1539 * The "path" member can't be initialized yet because string constants 1540 * cannot yet be accessed. Below we will set it correctly. 1541 */ 1542 memset(&objtmp, 0, sizeof(objtmp)); 1543 objtmp.path = NULL; 1544 objtmp.rtld = true; 1545 objtmp.mapbase = mapbase; 1546 #ifdef PIC 1547 objtmp.relocbase = mapbase; 1548 #endif 1549 if (RTLD_IS_DYNAMIC()) { 1550 objtmp.dynamic = rtld_dynamic(&objtmp); 1551 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1552 assert(objtmp.needed == NULL); 1553 assert(!objtmp.textrel); 1554 1555 /* 1556 * Temporarily put the dynamic linker entry into the object list, so 1557 * that symbols can be found. 1558 */ 1559 1560 relocate_objects(&objtmp, true, &objtmp, NULL); 1561 } 1562 1563 /* Initialize the object list. */ 1564 obj_tail = &obj_list; 1565 1566 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1567 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1568 1569 #ifdef ENABLE_OSRELDATE 1570 if (aux_info[AT_OSRELDATE] != NULL) 1571 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1572 #endif 1573 1574 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1575 1576 /* Replace the path with a dynamically allocated copy. */ 1577 obj_rtld.path = xstrdup(PATH_RTLD); 1578 1579 r_debug.r_brk = r_debug_state; 1580 r_debug.r_state = RT_CONSISTENT; 1581 } 1582 1583 /* 1584 * Add the init functions from a needed object list (and its recursive 1585 * needed objects) to "list". This is not used directly; it is a helper 1586 * function for initlist_add_objects(). The write lock must be held 1587 * when this function is called. 1588 */ 1589 static void 1590 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1591 { 1592 /* Recursively process the successor needed objects. */ 1593 if (needed->next != NULL) 1594 initlist_add_neededs(needed->next, list); 1595 1596 /* Process the current needed object. */ 1597 if (needed->obj != NULL) 1598 initlist_add_objects(needed->obj, &needed->obj->next, list); 1599 } 1600 1601 /* 1602 * Scan all of the DAGs rooted in the range of objects from "obj" to 1603 * "tail" and add their init functions to "list". This recurses over 1604 * the DAGs and ensure the proper init ordering such that each object's 1605 * needed libraries are initialized before the object itself. At the 1606 * same time, this function adds the objects to the global finalization 1607 * list "list_fini" in the opposite order. The write lock must be 1608 * held when this function is called. 1609 */ 1610 static void 1611 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1612 { 1613 if (obj->init_scanned || obj->init_done) 1614 return; 1615 obj->init_scanned = true; 1616 1617 /* Recursively process the successor objects. */ 1618 if (&obj->next != tail) 1619 initlist_add_objects(obj->next, tail, list); 1620 1621 /* Recursively process the needed objects. */ 1622 if (obj->needed != NULL) 1623 initlist_add_neededs(obj->needed, list); 1624 1625 /* Add the object to the init list. */ 1626 if (obj->init != (Elf_Addr)NULL) 1627 objlist_push_tail(list, obj); 1628 1629 /* Add the object to the global fini list in the reverse order. */ 1630 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1631 objlist_push_head(&list_fini, obj); 1632 obj->on_fini_list = true; 1633 } 1634 } 1635 1636 #ifndef FPTR_TARGET 1637 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1638 #endif 1639 1640 static bool 1641 is_exported(const Elf_Sym *def) 1642 { 1643 Elf_Addr value; 1644 const func_ptr_type *p; 1645 1646 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value); 1647 for (p = exports; *p != NULL; p++) 1648 if (FPTR_TARGET(*p) == value) 1649 return true; 1650 return false; 1651 } 1652 1653 static void 1654 free_needed_filtees(Needed_Entry *n) 1655 { 1656 Needed_Entry *needed, *needed1; 1657 1658 for (needed = n; needed != NULL; needed = needed->next) { 1659 if (needed->obj != NULL) { 1660 dlclose(needed->obj); 1661 needed->obj = NULL; 1662 } 1663 } 1664 for (needed = n; needed != NULL; needed = needed1) { 1665 needed1 = needed->next; 1666 free(needed); 1667 } 1668 } 1669 1670 static void 1671 unload_filtees(Obj_Entry *obj) 1672 { 1673 1674 free_needed_filtees(obj->needed_filtees); 1675 obj->needed_filtees = NULL; 1676 free_needed_filtees(obj->needed_aux_filtees); 1677 obj->needed_aux_filtees = NULL; 1678 obj->filtees_loaded = false; 1679 } 1680 1681 static void 1682 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags) 1683 { 1684 1685 for (; needed != NULL; needed = needed->next) { 1686 needed->obj = dlopen_object(obj->strtab + needed->name, obj, 1687 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1688 RTLD_LOCAL); 1689 } 1690 } 1691 1692 static void 1693 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1694 { 1695 1696 lock_restart_for_upgrade(lockstate); 1697 if (!obj->filtees_loaded) { 1698 load_filtee1(obj, obj->needed_filtees, flags); 1699 load_filtee1(obj, obj->needed_aux_filtees, flags); 1700 obj->filtees_loaded = true; 1701 } 1702 } 1703 1704 static int 1705 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1706 { 1707 Obj_Entry *obj1; 1708 1709 for (; needed != NULL; needed = needed->next) { 1710 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1711 flags & ~RTLD_LO_NOLOAD); 1712 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1713 return (-1); 1714 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1715 dbg("obj %s nodelete", obj1->path); 1716 init_dag(obj1); 1717 ref_dag(obj1); 1718 obj1->ref_nodel = true; 1719 } 1720 } 1721 return (0); 1722 } 1723 1724 /* 1725 * Given a shared object, traverse its list of needed objects, and load 1726 * each of them. Returns 0 on success. Generates an error message and 1727 * returns -1 on failure. 1728 */ 1729 static int 1730 load_needed_objects(Obj_Entry *first, int flags) 1731 { 1732 Obj_Entry *obj; 1733 1734 for (obj = first; obj != NULL; obj = obj->next) { 1735 if (process_needed(obj, obj->needed, flags) == -1) 1736 return (-1); 1737 } 1738 return (0); 1739 } 1740 1741 static int 1742 load_preload_objects(void) 1743 { 1744 char *p = ld_preload; 1745 static const char delim[] = " \t:;"; 1746 1747 if (p == NULL) 1748 return 0; 1749 1750 p += strspn(p, delim); 1751 while (*p != '\0') { 1752 size_t len = strcspn(p, delim); 1753 char savech; 1754 Obj_Entry *obj; 1755 SymLook req; 1756 int res; 1757 1758 savech = p[len]; 1759 p[len] = '\0'; 1760 obj = load_object(p, NULL, 0); 1761 if (obj == NULL) 1762 return -1; /* XXX - cleanup */ 1763 p[len] = savech; 1764 p += len; 1765 p += strspn(p, delim); 1766 1767 /* Check for the magic tracing function */ 1768 symlook_init(&req, RTLD_FUNCTRACE); 1769 res = symlook_obj(&req, obj); 1770 if (res == 0) { 1771 rtld_functrace = (void *)(req.defobj_out->relocbase + 1772 req.sym_out->st_value); 1773 rtld_functrace_obj = req.defobj_out; 1774 } 1775 } 1776 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1777 return 0; 1778 } 1779 1780 /* 1781 * Load a shared object into memory, if it is not already loaded. 1782 * 1783 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1784 * on failure. 1785 */ 1786 static Obj_Entry * 1787 load_object(const char *name, const Obj_Entry *refobj, int flags) 1788 { 1789 Obj_Entry *obj; 1790 int fd = -1; 1791 struct stat sb; 1792 char *path; 1793 1794 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1795 if (object_match_name(obj, name)) 1796 return obj; 1797 1798 path = find_library(name, refobj); 1799 if (path == NULL) 1800 return NULL; 1801 1802 /* 1803 * If we didn't find a match by pathname, open the file and check 1804 * again by device and inode. This avoids false mismatches caused 1805 * by multiple links or ".." in pathnames. 1806 * 1807 * To avoid a race, we open the file and use fstat() rather than 1808 * using stat(). 1809 */ 1810 if ((fd = open(path, O_RDONLY)) == -1) { 1811 _rtld_error("Cannot open \"%s\"", path); 1812 free(path); 1813 return NULL; 1814 } 1815 if (fstat(fd, &sb) == -1) { 1816 _rtld_error("Cannot fstat \"%s\"", path); 1817 close(fd); 1818 free(path); 1819 return NULL; 1820 } 1821 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1822 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1823 break; 1824 if (obj != NULL) { 1825 object_add_name(obj, name); 1826 free(path); 1827 close(fd); 1828 return obj; 1829 } 1830 if (flags & RTLD_LO_NOLOAD) { 1831 free(path); 1832 close(fd); 1833 return (NULL); 1834 } 1835 1836 /* First use of this object, so we must map it in */ 1837 obj = do_load_object(fd, name, path, &sb, flags); 1838 if (obj == NULL) 1839 free(path); 1840 close(fd); 1841 1842 return obj; 1843 } 1844 1845 static Obj_Entry * 1846 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1847 int flags) 1848 { 1849 Obj_Entry *obj; 1850 struct statfs fs; 1851 1852 /* 1853 * but first, make sure that environment variables haven't been 1854 * used to circumvent the noexec flag on a filesystem. 1855 */ 1856 if (dangerous_ld_env) { 1857 if (fstatfs(fd, &fs) != 0) { 1858 _rtld_error("Cannot fstatfs \"%s\"", path); 1859 return NULL; 1860 } 1861 if (fs.f_flags & MNT_NOEXEC) { 1862 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1863 return NULL; 1864 } 1865 } 1866 dbg("loading \"%s\"", path); 1867 obj = map_object(fd, path, sbp); 1868 if (obj == NULL) 1869 return NULL; 1870 1871 object_add_name(obj, name); 1872 obj->path = path; 1873 digest_dynamic(obj, 0); 1874 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1875 RTLD_LO_DLOPEN) { 1876 dbg("refusing to load non-loadable \"%s\"", obj->path); 1877 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1878 munmap(obj->mapbase, obj->mapsize); 1879 obj_free(obj); 1880 return (NULL); 1881 } 1882 1883 *obj_tail = obj; 1884 obj_tail = &obj->next; 1885 obj_count++; 1886 obj_loads++; 1887 linkmap_add(obj); /* for GDB & dlinfo() */ 1888 max_stack_flags |= obj->stack_flags; 1889 1890 dbg(" %p .. %p: %s", obj->mapbase, 1891 obj->mapbase + obj->mapsize - 1, obj->path); 1892 if (obj->textrel) 1893 dbg(" WARNING: %s has impure text", obj->path); 1894 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1895 obj->path); 1896 1897 return obj; 1898 } 1899 1900 static Obj_Entry * 1901 obj_from_addr(const void *addr) 1902 { 1903 Obj_Entry *obj; 1904 1905 for (obj = obj_list; obj != NULL; obj = obj->next) { 1906 if (addr < (void *) obj->mapbase) 1907 continue; 1908 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1909 return obj; 1910 } 1911 return NULL; 1912 } 1913 1914 /* 1915 * Call the finalization functions for each of the objects in "list" 1916 * belonging to the DAG of "root" and referenced once. If NULL "root" 1917 * is specified, every finalization function will be called regardless 1918 * of the reference count and the list elements won't be freed. All of 1919 * the objects are expected to have non-NULL fini functions. 1920 */ 1921 static void 1922 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1923 { 1924 Objlist_Entry *elm; 1925 char *saved_msg; 1926 1927 assert(root == NULL || root->refcount == 1); 1928 1929 /* 1930 * Preserve the current error message since a fini function might 1931 * call into the dynamic linker and overwrite it. 1932 */ 1933 saved_msg = errmsg_save(); 1934 do { 1935 STAILQ_FOREACH(elm, list, link) { 1936 if (root != NULL && (elm->obj->refcount != 1 || 1937 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1938 continue; 1939 dbg("calling fini function for %s at %p", elm->obj->path, 1940 (void *)elm->obj->fini); 1941 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1942 elm->obj->path); 1943 /* Remove object from fini list to prevent recursive invocation. */ 1944 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1945 /* 1946 * XXX: If a dlopen() call references an object while the 1947 * fini function is in progress, we might end up trying to 1948 * unload the referenced object in dlclose() or the object 1949 * won't be unloaded although its fini function has been 1950 * called. 1951 */ 1952 lock_release(rtld_bind_lock, lockstate); 1953 call_initfini_pointer(elm->obj, elm->obj->fini); 1954 wlock_acquire(rtld_bind_lock, lockstate); 1955 /* No need to free anything if process is going down. */ 1956 if (root != NULL) 1957 free(elm); 1958 /* 1959 * We must restart the list traversal after every fini call 1960 * because a dlclose() call from the fini function or from 1961 * another thread might have modified the reference counts. 1962 */ 1963 break; 1964 } 1965 } while (elm != NULL); 1966 errmsg_restore(saved_msg); 1967 } 1968 1969 /* 1970 * Call the initialization functions for each of the objects in 1971 * "list". All of the objects are expected to have non-NULL init 1972 * functions. 1973 */ 1974 static void 1975 objlist_call_init(Objlist *list, RtldLockState *lockstate) 1976 { 1977 Objlist_Entry *elm; 1978 Obj_Entry *obj; 1979 char *saved_msg; 1980 1981 /* 1982 * Clean init_scanned flag so that objects can be rechecked and 1983 * possibly initialized earlier if any of vectors called below 1984 * cause the change by using dlopen. 1985 */ 1986 for (obj = obj_list; obj != NULL; obj = obj->next) 1987 obj->init_scanned = false; 1988 1989 /* 1990 * Preserve the current error message since an init function might 1991 * call into the dynamic linker and overwrite it. 1992 */ 1993 saved_msg = errmsg_save(); 1994 STAILQ_FOREACH(elm, list, link) { 1995 if (elm->obj->init_done) /* Initialized early. */ 1996 continue; 1997 dbg("calling init function for %s at %p", elm->obj->path, 1998 (void *)elm->obj->init); 1999 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 2000 elm->obj->path); 2001 /* 2002 * Race: other thread might try to use this object before current 2003 * one completes the initilization. Not much can be done here 2004 * without better locking. 2005 */ 2006 elm->obj->init_done = true; 2007 lock_release(rtld_bind_lock, lockstate); 2008 call_initfini_pointer(elm->obj, elm->obj->init); 2009 wlock_acquire(rtld_bind_lock, lockstate); 2010 } 2011 errmsg_restore(saved_msg); 2012 } 2013 2014 static void 2015 objlist_clear(Objlist *list) 2016 { 2017 Objlist_Entry *elm; 2018 2019 while (!STAILQ_EMPTY(list)) { 2020 elm = STAILQ_FIRST(list); 2021 STAILQ_REMOVE_HEAD(list, link); 2022 free(elm); 2023 } 2024 } 2025 2026 static Objlist_Entry * 2027 objlist_find(Objlist *list, const Obj_Entry *obj) 2028 { 2029 Objlist_Entry *elm; 2030 2031 STAILQ_FOREACH(elm, list, link) 2032 if (elm->obj == obj) 2033 return elm; 2034 return NULL; 2035 } 2036 2037 static void 2038 objlist_init(Objlist *list) 2039 { 2040 STAILQ_INIT(list); 2041 } 2042 2043 static void 2044 objlist_push_head(Objlist *list, Obj_Entry *obj) 2045 { 2046 Objlist_Entry *elm; 2047 2048 elm = NEW(Objlist_Entry); 2049 elm->obj = obj; 2050 STAILQ_INSERT_HEAD(list, elm, link); 2051 } 2052 2053 static void 2054 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2055 { 2056 Objlist_Entry *elm; 2057 2058 elm = NEW(Objlist_Entry); 2059 elm->obj = obj; 2060 STAILQ_INSERT_TAIL(list, elm, link); 2061 } 2062 2063 static void 2064 objlist_remove(Objlist *list, Obj_Entry *obj) 2065 { 2066 Objlist_Entry *elm; 2067 2068 if ((elm = objlist_find(list, obj)) != NULL) { 2069 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2070 free(elm); 2071 } 2072 } 2073 2074 /* 2075 * Relocate newly-loaded shared objects. The argument is a pointer to 2076 * the Obj_Entry for the first such object. All objects from the first 2077 * to the end of the list of objects are relocated. Returns 0 on success, 2078 * or -1 on failure. 2079 */ 2080 static int 2081 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2082 RtldLockState *lockstate) 2083 { 2084 Obj_Entry *obj; 2085 2086 for (obj = first; obj != NULL; obj = obj->next) { 2087 if (obj != rtldobj) 2088 dbg("relocating \"%s\"", obj->path); 2089 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 2090 obj->symtab == NULL || obj->strtab == NULL) { 2091 _rtld_error("%s: Shared object has no run-time symbol table", 2092 obj->path); 2093 return -1; 2094 } 2095 2096 if (obj->textrel) { 2097 /* There are relocations to the write-protected text segment. */ 2098 if (mprotect(obj->mapbase, obj->textsize, 2099 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2100 _rtld_error("%s: Cannot write-enable text segment: %s", 2101 obj->path, strerror(errno)); 2102 return -1; 2103 } 2104 } 2105 2106 /* Process the non-PLT relocations. */ 2107 if (reloc_non_plt(obj, rtldobj, lockstate)) 2108 return -1; 2109 2110 /* 2111 * Reprotect the text segment. Make sure it is included in the 2112 * core dump since we modified it. This unfortunately causes the 2113 * entire text segment to core-out but we don't have much of a 2114 * choice. We could try to only reenable core dumps on pages 2115 * in which relocations occured but that is likely most of the text 2116 * pages anyway, and even that would not work because the rest of 2117 * the text pages would wind up as a read-only OBJT_DEFAULT object 2118 * (created due to our modifications) backed by the original OBJT_VNODE 2119 * object, and the ELF coredump code is currently only able to dump 2120 * vnode records for pure vnode-backed mappings, not vnode backings 2121 * to memory objects. 2122 */ 2123 if (obj->textrel) { 2124 madvise(obj->mapbase, obj->textsize, MADV_CORE); 2125 if (mprotect(obj->mapbase, obj->textsize, 2126 PROT_READ|PROT_EXEC) == -1) { 2127 _rtld_error("%s: Cannot write-protect text segment: %s", 2128 obj->path, strerror(errno)); 2129 return -1; 2130 } 2131 } 2132 2133 2134 /* Set the special PLT or GOT entries. */ 2135 init_pltgot(obj); 2136 2137 /* Process the PLT relocations. */ 2138 if (reloc_plt(obj) == -1) 2139 return -1; 2140 /* Relocate the jump slots if we are doing immediate binding. */ 2141 if (obj->bind_now || bind_now) 2142 if (reloc_jmpslots(obj, lockstate) == -1) 2143 return -1; 2144 2145 /* 2146 * Set up the magic number and version in the Obj_Entry. These 2147 * were checked in the crt1.o from the original ElfKit, so we 2148 * set them for backward compatibility. 2149 */ 2150 obj->magic = RTLD_MAGIC; 2151 obj->version = RTLD_VERSION; 2152 2153 /* 2154 * Set relocated data to read-only status if protection specified 2155 */ 2156 2157 if (obj->relro_size) { 2158 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2159 _rtld_error("%s: Cannot enforce relro relocation: %s", 2160 obj->path, strerror(errno)); 2161 return -1; 2162 } 2163 } 2164 } 2165 2166 return (0); 2167 } 2168 2169 /* 2170 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2171 * referencing STT_GNU_IFUNC symbols is postponed till the other 2172 * relocations are done. The indirect functions specified as 2173 * ifunc are allowed to call other symbols, so we need to have 2174 * objects relocated before asking for resolution from indirects. 2175 * 2176 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2177 * instead of the usual lazy handling of PLT slots. It is 2178 * consistent with how GNU does it. 2179 */ 2180 static int 2181 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, RtldLockState *lockstate) 2182 { 2183 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2184 return (-1); 2185 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2186 reloc_gnu_ifunc(obj, lockstate) == -1) 2187 return (-1); 2188 return (0); 2189 } 2190 2191 static int 2192 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, RtldLockState *lockstate) 2193 { 2194 Obj_Entry *obj; 2195 2196 for (obj = first; obj != NULL; obj = obj->next) { 2197 if (resolve_object_ifunc(obj, bind_now, lockstate) == -1) 2198 return (-1); 2199 } 2200 return (0); 2201 } 2202 2203 static int 2204 initlist_objects_ifunc(Objlist *list, bool bind_now, RtldLockState *lockstate) 2205 { 2206 Objlist_Entry *elm; 2207 2208 STAILQ_FOREACH(elm, list, link) { 2209 if (resolve_object_ifunc(elm->obj, bind_now, lockstate) == -1) 2210 return (-1); 2211 } 2212 return (0); 2213 } 2214 2215 /* 2216 * Cleanup procedure. It will be called (by the atexit mechanism) just 2217 * before the process exits. 2218 */ 2219 static void 2220 rtld_exit(void) 2221 { 2222 RtldLockState lockstate; 2223 2224 wlock_acquire(rtld_bind_lock, &lockstate); 2225 dbg("rtld_exit()"); 2226 objlist_call_fini(&list_fini, NULL, &lockstate); 2227 /* No need to remove the items from the list, since we are exiting. */ 2228 if (!libmap_disable) 2229 lm_fini(); 2230 lock_release(rtld_bind_lock, &lockstate); 2231 } 2232 2233 static void * 2234 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2235 { 2236 if (path == NULL) 2237 return (NULL); 2238 2239 path += strspn(path, ":;"); 2240 while (*path != '\0') { 2241 size_t len; 2242 char *res; 2243 2244 len = strcspn(path, ":;"); 2245 res = callback(path, len, arg); 2246 2247 if (res != NULL) 2248 return (res); 2249 2250 path += len; 2251 path += strspn(path, ":;"); 2252 } 2253 2254 return (NULL); 2255 } 2256 2257 struct try_library_args { 2258 const char *name; 2259 size_t namelen; 2260 char *buffer; 2261 size_t buflen; 2262 }; 2263 2264 static void * 2265 try_library_path(const char *dir, size_t dirlen, void *param) 2266 { 2267 struct try_library_args *arg; 2268 2269 arg = param; 2270 if (*dir == '/' || trust) { 2271 char *pathname; 2272 2273 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2274 return (NULL); 2275 2276 pathname = arg->buffer; 2277 strncpy(pathname, dir, dirlen); 2278 pathname[dirlen] = '/'; 2279 strcpy(pathname + dirlen + 1, arg->name); 2280 2281 dbg(" Trying \"%s\"", pathname); 2282 if (access(pathname, F_OK) == 0) { /* We found it */ 2283 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2284 strcpy(pathname, arg->buffer); 2285 return (pathname); 2286 } 2287 } 2288 return (NULL); 2289 } 2290 2291 static char * 2292 search_library_path(const char *name, const char *path) 2293 { 2294 char *p; 2295 struct try_library_args arg; 2296 2297 if (path == NULL) 2298 return NULL; 2299 2300 arg.name = name; 2301 arg.namelen = strlen(name); 2302 arg.buffer = xmalloc(PATH_MAX); 2303 arg.buflen = PATH_MAX; 2304 2305 p = path_enumerate(path, try_library_path, &arg); 2306 2307 free(arg.buffer); 2308 2309 return (p); 2310 } 2311 2312 int 2313 dlclose(void *handle) 2314 { 2315 Obj_Entry *root; 2316 RtldLockState lockstate; 2317 2318 wlock_acquire(rtld_bind_lock, &lockstate); 2319 root = dlcheck(handle); 2320 if (root == NULL) { 2321 lock_release(rtld_bind_lock, &lockstate); 2322 return -1; 2323 } 2324 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2325 root->path); 2326 2327 /* Unreference the object and its dependencies. */ 2328 root->dl_refcount--; 2329 2330 if (root->refcount == 1) { 2331 /* 2332 * The object will be no longer referenced, so we must unload it. 2333 * First, call the fini functions. 2334 */ 2335 objlist_call_fini(&list_fini, root, &lockstate); 2336 2337 unref_dag(root); 2338 2339 /* Finish cleaning up the newly-unreferenced objects. */ 2340 GDB_STATE(RT_DELETE,&root->linkmap); 2341 unload_object(root); 2342 GDB_STATE(RT_CONSISTENT,NULL); 2343 } else 2344 unref_dag(root); 2345 2346 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2347 lock_release(rtld_bind_lock, &lockstate); 2348 return 0; 2349 } 2350 2351 char * 2352 dlerror(void) 2353 { 2354 char *msg = error_message; 2355 error_message = NULL; 2356 return msg; 2357 } 2358 2359 void * 2360 dlopen(const char *name, int mode) 2361 { 2362 RtldLockState lockstate; 2363 int lo_flags; 2364 2365 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2366 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2367 if (ld_tracing != NULL) { 2368 rlock_acquire(rtld_bind_lock, &lockstate); 2369 if (sigsetjmp(lockstate.env, 0) != 0) 2370 lock_upgrade(rtld_bind_lock, &lockstate); 2371 environ = (char **)*get_program_var_addr("environ", &lockstate); 2372 lock_release(rtld_bind_lock, &lockstate); 2373 } 2374 lo_flags = RTLD_LO_DLOPEN; 2375 if (mode & RTLD_NODELETE) 2376 lo_flags |= RTLD_LO_NODELETE; 2377 if (mode & RTLD_NOLOAD) 2378 lo_flags |= RTLD_LO_NOLOAD; 2379 if (ld_tracing != NULL) 2380 lo_flags |= RTLD_LO_TRACE; 2381 2382 return (dlopen_object(name, obj_main, lo_flags, 2383 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2384 } 2385 2386 static void 2387 dlopen_cleanup(Obj_Entry *obj) 2388 { 2389 2390 obj->dl_refcount--; 2391 unref_dag(obj); 2392 if (obj->refcount == 0) 2393 unload_object(obj); 2394 } 2395 2396 static Obj_Entry * 2397 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode) 2398 { 2399 Obj_Entry **old_obj_tail; 2400 Obj_Entry *obj; 2401 Objlist initlist; 2402 RtldLockState lockstate; 2403 int result; 2404 2405 objlist_init(&initlist); 2406 2407 wlock_acquire(rtld_bind_lock, &lockstate); 2408 GDB_STATE(RT_ADD,NULL); 2409 2410 old_obj_tail = obj_tail; 2411 obj = NULL; 2412 if (name == NULL) { 2413 obj = obj_main; 2414 obj->refcount++; 2415 } else { 2416 obj = load_object(name, refobj, lo_flags); 2417 } 2418 2419 if (obj) { 2420 obj->dl_refcount++; 2421 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2422 objlist_push_tail(&list_global, obj); 2423 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2424 assert(*old_obj_tail == obj); 2425 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN); 2426 init_dag(obj); 2427 ref_dag(obj); 2428 if (result != -1) 2429 result = rtld_verify_versions(&obj->dagmembers); 2430 if (result != -1 && ld_tracing) 2431 goto trace; 2432 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK) 2433 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) { 2434 dlopen_cleanup(obj); 2435 obj = NULL; 2436 } else { 2437 /* Make list of init functions to call. */ 2438 initlist_add_objects(obj, &obj->next, &initlist); 2439 } 2440 } else { 2441 2442 /* 2443 * Bump the reference counts for objects on this DAG. If 2444 * this is the first dlopen() call for the object that was 2445 * already loaded as a dependency, initialize the dag 2446 * starting at it. 2447 */ 2448 init_dag(obj); 2449 ref_dag(obj); 2450 2451 if ((lo_flags & RTLD_LO_TRACE) != 0) 2452 goto trace; 2453 } 2454 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2455 obj->z_nodelete) && !obj->ref_nodel) { 2456 dbg("obj %s nodelete", obj->path); 2457 ref_dag(obj); 2458 obj->z_nodelete = obj->ref_nodel = true; 2459 } 2460 } 2461 2462 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2463 name); 2464 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2465 2466 map_stacks_exec(&lockstate); 2467 2468 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2469 &lockstate) == -1) { 2470 objlist_clear(&initlist); 2471 dlopen_cleanup(obj); 2472 lock_release(rtld_bind_lock, &lockstate); 2473 return (NULL); 2474 } 2475 2476 /* Call the init functions. */ 2477 objlist_call_init(&initlist, &lockstate); 2478 objlist_clear(&initlist); 2479 lock_release(rtld_bind_lock, &lockstate); 2480 return obj; 2481 trace: 2482 trace_loaded_objects(obj); 2483 lock_release(rtld_bind_lock, &lockstate); 2484 exit(0); 2485 } 2486 2487 static void * 2488 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2489 int flags) 2490 { 2491 DoneList donelist; 2492 const Obj_Entry *obj, *defobj; 2493 const Elf_Sym *def; 2494 SymLook req; 2495 RtldLockState lockstate; 2496 int res; 2497 2498 def = NULL; 2499 defobj = NULL; 2500 symlook_init(&req, name); 2501 req.ventry = ve; 2502 req.flags = flags | SYMLOOK_IN_PLT; 2503 req.lockstate = &lockstate; 2504 2505 rlock_acquire(rtld_bind_lock, &lockstate); 2506 if (sigsetjmp(lockstate.env, 0) != 0) 2507 lock_upgrade(rtld_bind_lock, &lockstate); 2508 if (handle == NULL || handle == RTLD_NEXT || 2509 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2510 2511 if ((obj = obj_from_addr(retaddr)) == NULL) { 2512 _rtld_error("Cannot determine caller's shared object"); 2513 lock_release(rtld_bind_lock, &lockstate); 2514 return NULL; 2515 } 2516 if (handle == NULL) { /* Just the caller's shared object. */ 2517 res = symlook_obj(&req, obj); 2518 if (res == 0) { 2519 def = req.sym_out; 2520 defobj = req.defobj_out; 2521 } 2522 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2523 handle == RTLD_SELF) { /* ... caller included */ 2524 if (handle == RTLD_NEXT) 2525 obj = obj->next; 2526 for (; obj != NULL; obj = obj->next) { 2527 res = symlook_obj(&req, obj); 2528 if (res == 0) { 2529 if (def == NULL || 2530 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2531 def = req.sym_out; 2532 defobj = req.defobj_out; 2533 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2534 break; 2535 } 2536 } 2537 } 2538 /* 2539 * Search the dynamic linker itself, and possibly resolve the 2540 * symbol from there. This is how the application links to 2541 * dynamic linker services such as dlopen. 2542 */ 2543 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2544 res = symlook_obj(&req, &obj_rtld); 2545 if (res == 0 && is_exported(req.sym_out)) { 2546 def = req.sym_out; 2547 defobj = req.defobj_out; 2548 } 2549 } 2550 } else { 2551 assert(handle == RTLD_DEFAULT); 2552 res = symlook_default(&req, obj); 2553 if (res == 0) { 2554 defobj = req.defobj_out; 2555 def = req.sym_out; 2556 } 2557 } 2558 } else { 2559 if ((obj = dlcheck(handle)) == NULL) { 2560 lock_release(rtld_bind_lock, &lockstate); 2561 return NULL; 2562 } 2563 2564 donelist_init(&donelist); 2565 if (obj->mainprog) { 2566 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2567 res = symlook_global(&req, &donelist); 2568 if (res == 0) { 2569 def = req.sym_out; 2570 defobj = req.defobj_out; 2571 } 2572 /* 2573 * Search the dynamic linker itself, and possibly resolve the 2574 * symbol from there. This is how the application links to 2575 * dynamic linker services such as dlopen. 2576 */ 2577 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2578 res = symlook_obj(&req, &obj_rtld); 2579 if (res == 0) { 2580 def = req.sym_out; 2581 defobj = req.defobj_out; 2582 } 2583 } 2584 } 2585 else { 2586 /* Search the whole DAG rooted at the given object. */ 2587 res = symlook_list(&req, &obj->dagmembers, &donelist); 2588 if (res == 0) { 2589 def = req.sym_out; 2590 defobj = req.defobj_out; 2591 } 2592 } 2593 } 2594 2595 if (def != NULL) { 2596 lock_release(rtld_bind_lock, &lockstate); 2597 2598 /* 2599 * The value required by the caller is derived from the value 2600 * of the symbol. For the ia64 architecture, we need to 2601 * construct a function descriptor which the caller can use to 2602 * call the function with the right 'gp' value. For other 2603 * architectures and for non-functions, the value is simply 2604 * the relocated value of the symbol. 2605 */ 2606 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2607 return (make_function_pointer(def, defobj)); 2608 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 2609 return (rtld_resolve_ifunc(defobj, def)); 2610 else 2611 return (defobj->relocbase + def->st_value); 2612 } 2613 2614 _rtld_error("Undefined symbol \"%s\"", name); 2615 lock_release(rtld_bind_lock, &lockstate); 2616 return NULL; 2617 } 2618 2619 void * 2620 dlsym(void *handle, const char *name) 2621 { 2622 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2623 SYMLOOK_DLSYM); 2624 } 2625 2626 dlfunc_t 2627 dlfunc(void *handle, const char *name) 2628 { 2629 union { 2630 void *d; 2631 dlfunc_t f; 2632 } rv; 2633 2634 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2635 SYMLOOK_DLSYM); 2636 return (rv.f); 2637 } 2638 2639 void * 2640 dlvsym(void *handle, const char *name, const char *version) 2641 { 2642 Ver_Entry ventry; 2643 2644 ventry.name = version; 2645 ventry.file = NULL; 2646 ventry.hash = elf_hash(version); 2647 ventry.flags= 0; 2648 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2649 SYMLOOK_DLSYM); 2650 } 2651 2652 int 2653 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2654 { 2655 const Obj_Entry *obj; 2656 RtldLockState lockstate; 2657 2658 rlock_acquire(rtld_bind_lock, &lockstate); 2659 obj = obj_from_addr(addr); 2660 if (obj == NULL) { 2661 _rtld_error("No shared object contains address"); 2662 lock_release(rtld_bind_lock, &lockstate); 2663 return (0); 2664 } 2665 rtld_fill_dl_phdr_info(obj, phdr_info); 2666 lock_release(rtld_bind_lock, &lockstate); 2667 return (1); 2668 } 2669 2670 int 2671 dladdr(const void *addr, Dl_info *info) 2672 { 2673 const Obj_Entry *obj; 2674 const Elf_Sym *def; 2675 void *symbol_addr; 2676 unsigned long symoffset; 2677 RtldLockState lockstate; 2678 2679 rlock_acquire(rtld_bind_lock, &lockstate); 2680 obj = obj_from_addr(addr); 2681 if (obj == NULL) { 2682 _rtld_error("No shared object contains address"); 2683 lock_release(rtld_bind_lock, &lockstate); 2684 return 0; 2685 } 2686 info->dli_fname = obj->path; 2687 info->dli_fbase = obj->mapbase; 2688 info->dli_saddr = NULL; 2689 info->dli_sname = NULL; 2690 2691 /* 2692 * Walk the symbol list looking for the symbol whose address is 2693 * closest to the address sent in. 2694 */ 2695 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2696 def = obj->symtab + symoffset; 2697 2698 /* 2699 * For skip the symbol if st_shndx is either SHN_UNDEF or 2700 * SHN_COMMON. 2701 */ 2702 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2703 continue; 2704 2705 /* 2706 * If the symbol is greater than the specified address, or if it 2707 * is further away from addr than the current nearest symbol, 2708 * then reject it. 2709 */ 2710 symbol_addr = obj->relocbase + def->st_value; 2711 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2712 continue; 2713 2714 /* Update our idea of the nearest symbol. */ 2715 info->dli_sname = obj->strtab + def->st_name; 2716 info->dli_saddr = symbol_addr; 2717 2718 /* Exact match? */ 2719 if (info->dli_saddr == addr) 2720 break; 2721 } 2722 lock_release(rtld_bind_lock, &lockstate); 2723 return 1; 2724 } 2725 2726 int 2727 dlinfo(void *handle, int request, void *p) 2728 { 2729 const Obj_Entry *obj; 2730 RtldLockState lockstate; 2731 int error; 2732 2733 rlock_acquire(rtld_bind_lock, &lockstate); 2734 2735 if (handle == NULL || handle == RTLD_SELF) { 2736 void *retaddr; 2737 2738 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2739 if ((obj = obj_from_addr(retaddr)) == NULL) 2740 _rtld_error("Cannot determine caller's shared object"); 2741 } else 2742 obj = dlcheck(handle); 2743 2744 if (obj == NULL) { 2745 lock_release(rtld_bind_lock, &lockstate); 2746 return (-1); 2747 } 2748 2749 error = 0; 2750 switch (request) { 2751 case RTLD_DI_LINKMAP: 2752 *((struct link_map const **)p) = &obj->linkmap; 2753 break; 2754 case RTLD_DI_ORIGIN: 2755 error = rtld_dirname(obj->path, p); 2756 break; 2757 2758 case RTLD_DI_SERINFOSIZE: 2759 case RTLD_DI_SERINFO: 2760 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2761 break; 2762 2763 default: 2764 _rtld_error("Invalid request %d passed to dlinfo()", request); 2765 error = -1; 2766 } 2767 2768 lock_release(rtld_bind_lock, &lockstate); 2769 2770 return (error); 2771 } 2772 2773 static void 2774 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2775 { 2776 2777 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2778 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2779 STAILQ_FIRST(&obj->names)->name : obj->path; 2780 phdr_info->dlpi_phdr = obj->phdr; 2781 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2782 phdr_info->dlpi_tls_modid = obj->tlsindex; 2783 phdr_info->dlpi_tls_data = obj->tlsinit; 2784 phdr_info->dlpi_adds = obj_loads; 2785 phdr_info->dlpi_subs = obj_loads - obj_count; 2786 } 2787 2788 int 2789 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2790 { 2791 struct dl_phdr_info phdr_info; 2792 const Obj_Entry *obj; 2793 RtldLockState bind_lockstate, phdr_lockstate; 2794 int error; 2795 2796 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2797 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2798 2799 error = 0; 2800 2801 for (obj = obj_list; obj != NULL; obj = obj->next) { 2802 rtld_fill_dl_phdr_info(obj, &phdr_info); 2803 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2804 break; 2805 2806 } 2807 lock_release(rtld_bind_lock, &bind_lockstate); 2808 lock_release(rtld_phdr_lock, &phdr_lockstate); 2809 2810 return (error); 2811 } 2812 2813 struct fill_search_info_args { 2814 int request; 2815 unsigned int flags; 2816 Dl_serinfo *serinfo; 2817 Dl_serpath *serpath; 2818 char *strspace; 2819 }; 2820 2821 static void * 2822 fill_search_info(const char *dir, size_t dirlen, void *param) 2823 { 2824 struct fill_search_info_args *arg; 2825 2826 arg = param; 2827 2828 if (arg->request == RTLD_DI_SERINFOSIZE) { 2829 arg->serinfo->dls_cnt ++; 2830 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2831 } else { 2832 struct dl_serpath *s_entry; 2833 2834 s_entry = arg->serpath; 2835 s_entry->dls_name = arg->strspace; 2836 s_entry->dls_flags = arg->flags; 2837 2838 strncpy(arg->strspace, dir, dirlen); 2839 arg->strspace[dirlen] = '\0'; 2840 2841 arg->strspace += dirlen + 1; 2842 arg->serpath++; 2843 } 2844 2845 return (NULL); 2846 } 2847 2848 static int 2849 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2850 { 2851 struct dl_serinfo _info; 2852 struct fill_search_info_args args; 2853 2854 args.request = RTLD_DI_SERINFOSIZE; 2855 args.serinfo = &_info; 2856 2857 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2858 _info.dls_cnt = 0; 2859 2860 path_enumerate(ld_library_path, fill_search_info, &args); 2861 path_enumerate(obj->rpath, fill_search_info, &args); 2862 path_enumerate(gethints(), fill_search_info, &args); 2863 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2864 2865 2866 if (request == RTLD_DI_SERINFOSIZE) { 2867 info->dls_size = _info.dls_size; 2868 info->dls_cnt = _info.dls_cnt; 2869 return (0); 2870 } 2871 2872 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2873 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2874 return (-1); 2875 } 2876 2877 args.request = RTLD_DI_SERINFO; 2878 args.serinfo = info; 2879 args.serpath = &info->dls_serpath[0]; 2880 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2881 2882 args.flags = LA_SER_LIBPATH; 2883 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2884 return (-1); 2885 2886 args.flags = LA_SER_RUNPATH; 2887 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2888 return (-1); 2889 2890 args.flags = LA_SER_CONFIG; 2891 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2892 return (-1); 2893 2894 args.flags = LA_SER_DEFAULT; 2895 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2896 return (-1); 2897 return (0); 2898 } 2899 2900 static int 2901 rtld_dirname(const char *path, char *bname) 2902 { 2903 const char *endp; 2904 2905 /* Empty or NULL string gets treated as "." */ 2906 if (path == NULL || *path == '\0') { 2907 bname[0] = '.'; 2908 bname[1] = '\0'; 2909 return (0); 2910 } 2911 2912 /* Strip trailing slashes */ 2913 endp = path + strlen(path) - 1; 2914 while (endp > path && *endp == '/') 2915 endp--; 2916 2917 /* Find the start of the dir */ 2918 while (endp > path && *endp != '/') 2919 endp--; 2920 2921 /* Either the dir is "/" or there are no slashes */ 2922 if (endp == path) { 2923 bname[0] = *endp == '/' ? '/' : '.'; 2924 bname[1] = '\0'; 2925 return (0); 2926 } else { 2927 do { 2928 endp--; 2929 } while (endp > path && *endp == '/'); 2930 } 2931 2932 if (endp - path + 2 > PATH_MAX) 2933 { 2934 _rtld_error("Filename is too long: %s", path); 2935 return(-1); 2936 } 2937 2938 strncpy(bname, path, endp - path + 1); 2939 bname[endp - path + 1] = '\0'; 2940 return (0); 2941 } 2942 2943 static int 2944 rtld_dirname_abs(const char *path, char *base) 2945 { 2946 char base_rel[PATH_MAX]; 2947 2948 if (rtld_dirname(path, base) == -1) 2949 return (-1); 2950 if (base[0] == '/') 2951 return (0); 2952 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2953 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2954 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2955 return (-1); 2956 strcpy(base, base_rel); 2957 return (0); 2958 } 2959 2960 static void 2961 linkmap_add(Obj_Entry *obj) 2962 { 2963 struct link_map *l = &obj->linkmap; 2964 struct link_map *prev; 2965 2966 obj->linkmap.l_name = obj->path; 2967 obj->linkmap.l_addr = obj->mapbase; 2968 obj->linkmap.l_ld = obj->dynamic; 2969 #ifdef __mips__ 2970 /* GDB needs load offset on MIPS to use the symbols */ 2971 obj->linkmap.l_offs = obj->relocbase; 2972 #endif 2973 2974 if (r_debug.r_map == NULL) { 2975 r_debug.r_map = l; 2976 return; 2977 } 2978 2979 /* 2980 * Scan to the end of the list, but not past the entry for the 2981 * dynamic linker, which we want to keep at the very end. 2982 */ 2983 for (prev = r_debug.r_map; 2984 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2985 prev = prev->l_next) 2986 ; 2987 2988 /* Link in the new entry. */ 2989 l->l_prev = prev; 2990 l->l_next = prev->l_next; 2991 if (l->l_next != NULL) 2992 l->l_next->l_prev = l; 2993 prev->l_next = l; 2994 } 2995 2996 static void 2997 linkmap_delete(Obj_Entry *obj) 2998 { 2999 struct link_map *l = &obj->linkmap; 3000 3001 if (l->l_prev == NULL) { 3002 if ((r_debug.r_map = l->l_next) != NULL) 3003 l->l_next->l_prev = NULL; 3004 return; 3005 } 3006 3007 if ((l->l_prev->l_next = l->l_next) != NULL) 3008 l->l_next->l_prev = l->l_prev; 3009 } 3010 3011 /* 3012 * Function for the debugger to set a breakpoint on to gain control. 3013 * 3014 * The two parameters allow the debugger to easily find and determine 3015 * what the runtime loader is doing and to whom it is doing it. 3016 * 3017 * When the loadhook trap is hit (r_debug_state, set at program 3018 * initialization), the arguments can be found on the stack: 3019 * 3020 * +8 struct link_map *m 3021 * +4 struct r_debug *rd 3022 * +0 RetAddr 3023 */ 3024 void 3025 r_debug_state(struct r_debug* rd, struct link_map *m) 3026 { 3027 /* 3028 * The following is a hack to force the compiler to emit calls to 3029 * this function, even when optimizing. If the function is empty, 3030 * the compiler is not obliged to emit any code for calls to it, 3031 * even when marked __noinline. However, gdb depends on those 3032 * calls being made. 3033 */ 3034 __asm __volatile("" : : : "memory"); 3035 } 3036 3037 /* 3038 * Get address of the pointer variable in the main program. 3039 * Prefer non-weak symbol over the weak one. 3040 */ 3041 static const void ** 3042 get_program_var_addr(const char *name, RtldLockState *lockstate) 3043 { 3044 SymLook req; 3045 DoneList donelist; 3046 3047 symlook_init(&req, name); 3048 req.lockstate = lockstate; 3049 donelist_init(&donelist); 3050 if (symlook_global(&req, &donelist) != 0) 3051 return (NULL); 3052 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3053 return ((const void **)make_function_pointer(req.sym_out, 3054 req.defobj_out)); 3055 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3056 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3057 else 3058 return ((const void **)(req.defobj_out->relocbase + 3059 req.sym_out->st_value)); 3060 } 3061 3062 /* 3063 * Set a pointer variable in the main program to the given value. This 3064 * is used to set key variables such as "environ" before any of the 3065 * init functions are called. 3066 */ 3067 static void 3068 set_program_var(const char *name, const void *value) 3069 { 3070 const void **addr; 3071 3072 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3073 dbg("\"%s\": *%p <-- %p", name, addr, value); 3074 *addr = value; 3075 } 3076 } 3077 3078 /* 3079 * Search the global objects, including dependencies and main object, 3080 * for the given symbol. 3081 */ 3082 static int 3083 symlook_global(SymLook *req, DoneList *donelist) 3084 { 3085 SymLook req1; 3086 const Objlist_Entry *elm; 3087 int res; 3088 3089 symlook_init_from_req(&req1, req); 3090 3091 /* Search all objects loaded at program start up. */ 3092 if (req->defobj_out == NULL || 3093 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3094 res = symlook_list(&req1, &list_main, donelist); 3095 if (res == 0 && (req->defobj_out == NULL || 3096 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3097 req->sym_out = req1.sym_out; 3098 req->defobj_out = req1.defobj_out; 3099 assert(req->defobj_out != NULL); 3100 } 3101 } 3102 3103 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3104 STAILQ_FOREACH(elm, &list_global, link) { 3105 if (req->defobj_out != NULL && 3106 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3107 break; 3108 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3109 if (res == 0 && (req->defobj_out == NULL || 3110 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3111 req->sym_out = req1.sym_out; 3112 req->defobj_out = req1.defobj_out; 3113 assert(req->defobj_out != NULL); 3114 } 3115 } 3116 3117 return (req->sym_out != NULL ? 0 : ESRCH); 3118 } 3119 3120 /* 3121 * This is a special version of getenv which is far more efficient 3122 * at finding LD_ environment vars. 3123 */ 3124 static 3125 const char * 3126 _getenv_ld(const char *id) 3127 { 3128 const char *envp; 3129 int i, j; 3130 int idlen = strlen(id); 3131 3132 if (ld_index == LD_ARY_CACHE) 3133 return(getenv(id)); 3134 if (ld_index == 0) { 3135 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 3136 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 3137 ld_ary[j++] = envp; 3138 } 3139 if (j == 0) 3140 ld_ary[j++] = ""; 3141 ld_index = j; 3142 } 3143 for (i = ld_index - 1; i >= 0; --i) { 3144 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 3145 return(ld_ary[i] + idlen + 1); 3146 } 3147 return(NULL); 3148 } 3149 3150 /* 3151 * Given a symbol name in a referencing object, find the corresponding 3152 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3153 * no definition was found. Returns a pointer to the Obj_Entry of the 3154 * defining object via the reference parameter DEFOBJ_OUT. 3155 */ 3156 static int 3157 symlook_default(SymLook *req, const Obj_Entry *refobj) 3158 { 3159 DoneList donelist; 3160 const Objlist_Entry *elm; 3161 SymLook req1; 3162 int res; 3163 3164 donelist_init(&donelist); 3165 symlook_init_from_req(&req1, req); 3166 3167 /* Look first in the referencing object if linked symbolically. */ 3168 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3169 res = symlook_obj(&req1, refobj); 3170 if (res == 0) { 3171 req->sym_out = req1.sym_out; 3172 req->defobj_out = req1.defobj_out; 3173 assert(req->defobj_out != NULL); 3174 } 3175 } 3176 3177 symlook_global(req, &donelist); 3178 3179 /* Search all dlopened DAGs containing the referencing object. */ 3180 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3181 if (req->sym_out != NULL && 3182 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3183 break; 3184 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3185 if (res == 0 && (req->sym_out == NULL || 3186 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3187 req->sym_out = req1.sym_out; 3188 req->defobj_out = req1.defobj_out; 3189 assert(req->defobj_out != NULL); 3190 } 3191 } 3192 3193 /* 3194 * Search the dynamic linker itself, and possibly resolve the 3195 * symbol from there. This is how the application links to 3196 * dynamic linker services such as dlopen. Only the values listed 3197 * in the "exports" array can be resolved from the dynamic linker. 3198 */ 3199 if (req->sym_out == NULL || 3200 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3201 res = symlook_obj(&req1, &obj_rtld); 3202 if (res == 0 && is_exported(req1.sym_out)) { 3203 req->sym_out = req1.sym_out; 3204 req->defobj_out = req1.defobj_out; 3205 assert(req->defobj_out != NULL); 3206 } 3207 } 3208 3209 return (req->sym_out != NULL ? 0 : ESRCH); 3210 } 3211 3212 static int 3213 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3214 { 3215 const Elf_Sym *def; 3216 const Obj_Entry *defobj; 3217 const Objlist_Entry *elm; 3218 SymLook req1; 3219 int res; 3220 3221 def = NULL; 3222 defobj = NULL; 3223 STAILQ_FOREACH(elm, objlist, link) { 3224 if (donelist_check(dlp, elm->obj)) 3225 continue; 3226 symlook_init_from_req(&req1, req); 3227 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3228 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3229 def = req1.sym_out; 3230 defobj = req1.defobj_out; 3231 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3232 break; 3233 } 3234 } 3235 } 3236 if (def != NULL) { 3237 req->sym_out = def; 3238 req->defobj_out = defobj; 3239 return (0); 3240 } 3241 return (ESRCH); 3242 } 3243 3244 /* 3245 * Search the chain of DAGS cointed to by the given Needed_Entry 3246 * for a symbol of the given name. Each DAG is scanned completely 3247 * before advancing to the next one. Returns a pointer to the symbol, 3248 * or NULL if no definition was found. 3249 */ 3250 static int 3251 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3252 { 3253 const Elf_Sym *def; 3254 const Needed_Entry *n; 3255 const Obj_Entry *defobj; 3256 SymLook req1; 3257 int res; 3258 3259 def = NULL; 3260 defobj = NULL; 3261 symlook_init_from_req(&req1, req); 3262 for (n = needed; n != NULL; n = n->next) { 3263 if (n->obj == NULL || 3264 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3265 continue; 3266 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3267 def = req1.sym_out; 3268 defobj = req1.defobj_out; 3269 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3270 break; 3271 } 3272 } 3273 if (def != NULL) { 3274 req->sym_out = def; 3275 req->defobj_out = defobj; 3276 return (0); 3277 } 3278 return (ESRCH); 3279 } 3280 3281 /* 3282 * Search the symbol table of a single shared object for a symbol of 3283 * the given name and version, if requested. Returns a pointer to the 3284 * symbol, or NULL if no definition was found. If the object is 3285 * filter, return filtered symbol from filtee. 3286 * 3287 * The symbol's hash value is passed in for efficiency reasons; that 3288 * eliminates many recomputations of the hash value. 3289 */ 3290 int 3291 symlook_obj(SymLook *req, const Obj_Entry *obj) 3292 { 3293 DoneList donelist; 3294 SymLook req1; 3295 int res, mres; 3296 3297 mres = symlook_obj1(req, obj); 3298 if (mres == 0) { 3299 if (obj->needed_filtees != NULL) { 3300 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3301 donelist_init(&donelist); 3302 symlook_init_from_req(&req1, req); 3303 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3304 if (res == 0) { 3305 req->sym_out = req1.sym_out; 3306 req->defobj_out = req1.defobj_out; 3307 } 3308 return (res); 3309 } 3310 if (obj->needed_aux_filtees != NULL) { 3311 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3312 donelist_init(&donelist); 3313 symlook_init_from_req(&req1, req); 3314 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3315 if (res == 0) { 3316 req->sym_out = req1.sym_out; 3317 req->defobj_out = req1.defobj_out; 3318 return (res); 3319 } 3320 } 3321 } 3322 return (mres); 3323 } 3324 3325 static int 3326 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3327 { 3328 unsigned long symnum; 3329 const Elf_Sym *vsymp; 3330 Elf_Versym verndx; 3331 int vcount; 3332 3333 if (obj->buckets == NULL) 3334 return (ESRCH); 3335 3336 vsymp = NULL; 3337 vcount = 0; 3338 symnum = obj->buckets[req->hash % obj->nbuckets]; 3339 3340 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3341 const Elf_Sym *symp; 3342 const char *strp; 3343 3344 if (symnum >= obj->nchains) 3345 return (ESRCH); /* Bad object */ 3346 3347 symp = obj->symtab + symnum; 3348 strp = obj->strtab + symp->st_name; 3349 3350 switch (ELF_ST_TYPE(symp->st_info)) { 3351 case STT_FUNC: 3352 case STT_NOTYPE: 3353 case STT_OBJECT: 3354 case STT_GNU_IFUNC: 3355 if (symp->st_value == 0) 3356 continue; 3357 /* fallthrough */ 3358 case STT_TLS: 3359 if (symp->st_shndx != SHN_UNDEF) 3360 break; 3361 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3362 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3363 break; 3364 /* fallthrough */ 3365 default: 3366 continue; 3367 } 3368 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3369 continue; 3370 3371 if (req->ventry == NULL) { 3372 if (obj->versyms != NULL) { 3373 verndx = VER_NDX(obj->versyms[symnum]); 3374 if (verndx > obj->vernum) { 3375 _rtld_error("%s: symbol %s references wrong version %d", 3376 obj->path, obj->strtab + symnum, verndx); 3377 continue; 3378 } 3379 /* 3380 * If we are not called from dlsym (i.e. this is a normal 3381 * relocation from unversioned binary), accept the symbol 3382 * immediately if it happens to have first version after 3383 * this shared object became versioned. Otherwise, if 3384 * symbol is versioned and not hidden, remember it. If it 3385 * is the only symbol with this name exported by the 3386 * shared object, it will be returned as a match at the 3387 * end of the function. If symbol is global (verndx < 2) 3388 * accept it unconditionally. 3389 */ 3390 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3391 verndx == VER_NDX_GIVEN) { 3392 req->sym_out = symp; 3393 req->defobj_out = obj; 3394 return (0); 3395 } 3396 else if (verndx >= VER_NDX_GIVEN) { 3397 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3398 if (vsymp == NULL) 3399 vsymp = symp; 3400 vcount ++; 3401 } 3402 continue; 3403 } 3404 } 3405 req->sym_out = symp; 3406 req->defobj_out = obj; 3407 return (0); 3408 } else { 3409 if (obj->versyms == NULL) { 3410 if (object_match_name(obj, req->ventry->name)) { 3411 _rtld_error("%s: object %s should provide version %s for " 3412 "symbol %s", obj_rtld.path, obj->path, 3413 req->ventry->name, obj->strtab + symnum); 3414 continue; 3415 } 3416 } else { 3417 verndx = VER_NDX(obj->versyms[symnum]); 3418 if (verndx > obj->vernum) { 3419 _rtld_error("%s: symbol %s references wrong version %d", 3420 obj->path, obj->strtab + symnum, verndx); 3421 continue; 3422 } 3423 if (obj->vertab[verndx].hash != req->ventry->hash || 3424 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3425 /* 3426 * Version does not match. Look if this is a global symbol 3427 * and if it is not hidden. If global symbol (verndx < 2) 3428 * is available, use it. Do not return symbol if we are 3429 * called by dlvsym, because dlvsym looks for a specific 3430 * version and default one is not what dlvsym wants. 3431 */ 3432 if ((req->flags & SYMLOOK_DLSYM) || 3433 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3434 (verndx >= VER_NDX_GIVEN)) 3435 continue; 3436 } 3437 } 3438 req->sym_out = symp; 3439 req->defobj_out = obj; 3440 return (0); 3441 } 3442 } 3443 if (vcount == 1) { 3444 req->sym_out = vsymp; 3445 req->defobj_out = obj; 3446 return (0); 3447 } 3448 return (ESRCH); 3449 } 3450 3451 static void 3452 trace_loaded_objects(Obj_Entry *obj) 3453 { 3454 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3455 int c; 3456 3457 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3458 main_local = ""; 3459 3460 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3461 fmt1 = "\t%o => %p (%x)\n"; 3462 3463 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3464 fmt2 = "\t%o (%x)\n"; 3465 3466 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 3467 3468 for (; obj; obj = obj->next) { 3469 Needed_Entry *needed; 3470 char *name, *path; 3471 bool is_lib; 3472 3473 if (list_containers && obj->needed != NULL) 3474 rtld_printf("%s:\n", obj->path); 3475 for (needed = obj->needed; needed; needed = needed->next) { 3476 if (needed->obj != NULL) { 3477 if (needed->obj->traced && !list_containers) 3478 continue; 3479 needed->obj->traced = true; 3480 path = needed->obj->path; 3481 } else 3482 path = "not found"; 3483 3484 name = (char *)obj->strtab + needed->name; 3485 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3486 3487 fmt = is_lib ? fmt1 : fmt2; 3488 while ((c = *fmt++) != '\0') { 3489 switch (c) { 3490 default: 3491 rtld_putchar(c); 3492 continue; 3493 case '\\': 3494 switch (c = *fmt) { 3495 case '\0': 3496 continue; 3497 case 'n': 3498 rtld_putchar('\n'); 3499 break; 3500 case 't': 3501 rtld_putchar('\t'); 3502 break; 3503 } 3504 break; 3505 case '%': 3506 switch (c = *fmt) { 3507 case '\0': 3508 continue; 3509 case '%': 3510 default: 3511 rtld_putchar(c); 3512 break; 3513 case 'A': 3514 rtld_putstr(main_local); 3515 break; 3516 case 'a': 3517 rtld_putstr(obj_main->path); 3518 break; 3519 case 'o': 3520 rtld_putstr(name); 3521 break; 3522 case 'p': 3523 rtld_putstr(path); 3524 break; 3525 case 'x': 3526 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 3527 0); 3528 break; 3529 } 3530 break; 3531 } 3532 ++fmt; 3533 } 3534 } 3535 } 3536 } 3537 3538 /* 3539 * Unload a dlopened object and its dependencies from memory and from 3540 * our data structures. It is assumed that the DAG rooted in the 3541 * object has already been unreferenced, and that the object has a 3542 * reference count of 0. 3543 */ 3544 static void 3545 unload_object(Obj_Entry *root) 3546 { 3547 Obj_Entry *obj; 3548 Obj_Entry **linkp; 3549 3550 assert(root->refcount == 0); 3551 3552 /* 3553 * Pass over the DAG removing unreferenced objects from 3554 * appropriate lists. 3555 */ 3556 unlink_object(root); 3557 3558 /* Unmap all objects that are no longer referenced. */ 3559 linkp = &obj_list->next; 3560 while ((obj = *linkp) != NULL) { 3561 if (obj->refcount == 0) { 3562 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3563 obj->path); 3564 dbg("unloading \"%s\"", obj->path); 3565 unload_filtees(root); 3566 munmap(obj->mapbase, obj->mapsize); 3567 linkmap_delete(obj); 3568 *linkp = obj->next; 3569 obj_count--; 3570 obj_free(obj); 3571 } else 3572 linkp = &obj->next; 3573 } 3574 obj_tail = linkp; 3575 } 3576 3577 static void 3578 unlink_object(Obj_Entry *root) 3579 { 3580 Objlist_Entry *elm; 3581 3582 if (root->refcount == 0) { 3583 /* Remove the object from the RTLD_GLOBAL list. */ 3584 objlist_remove(&list_global, root); 3585 3586 /* Remove the object from all objects' DAG lists. */ 3587 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3588 objlist_remove(&elm->obj->dldags, root); 3589 if (elm->obj != root) 3590 unlink_object(elm->obj); 3591 } 3592 } 3593 } 3594 3595 static void 3596 ref_dag(Obj_Entry *root) 3597 { 3598 Objlist_Entry *elm; 3599 3600 assert(root->dag_inited); 3601 STAILQ_FOREACH(elm, &root->dagmembers, link) 3602 elm->obj->refcount++; 3603 } 3604 3605 static void 3606 unref_dag(Obj_Entry *root) 3607 { 3608 Objlist_Entry *elm; 3609 3610 assert(root->dag_inited); 3611 STAILQ_FOREACH(elm, &root->dagmembers, link) 3612 elm->obj->refcount--; 3613 } 3614 3615 /* 3616 * Common code for MD __tls_get_addr(). 3617 */ 3618 void * 3619 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3620 { 3621 Elf_Addr* dtv = *dtvp; 3622 RtldLockState lockstate; 3623 3624 /* Check dtv generation in case new modules have arrived */ 3625 if (dtv[0] != tls_dtv_generation) { 3626 Elf_Addr* newdtv; 3627 int to_copy; 3628 3629 wlock_acquire(rtld_bind_lock, &lockstate); 3630 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3631 to_copy = dtv[1]; 3632 if (to_copy > tls_max_index) 3633 to_copy = tls_max_index; 3634 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3635 newdtv[0] = tls_dtv_generation; 3636 newdtv[1] = tls_max_index; 3637 free(dtv); 3638 lock_release(rtld_bind_lock, &lockstate); 3639 dtv = *dtvp = newdtv; 3640 } 3641 3642 /* Dynamically allocate module TLS if necessary */ 3643 if (!dtv[index + 1]) { 3644 /* Signal safe, wlock will block out signals. */ 3645 wlock_acquire(rtld_bind_lock, &lockstate); 3646 if (!dtv[index + 1]) 3647 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3648 lock_release(rtld_bind_lock, &lockstate); 3649 } 3650 return (void*) (dtv[index + 1] + offset); 3651 } 3652 3653 #if defined(RTLD_STATIC_TLS_VARIANT_II) 3654 3655 /* 3656 * Allocate the static TLS area. Return a pointer to the TCB. The 3657 * static area is based on negative offsets relative to the tcb. 3658 * 3659 * The TCB contains an errno pointer for the system call layer, but because 3660 * we are the RTLD we really have no idea how the caller was compiled so 3661 * the information has to be passed in. errno can either be: 3662 * 3663 * type 0 errno is a simple non-TLS global pointer. 3664 * (special case for e.g. libc_rtld) 3665 * type 1 errno accessed by GOT entry (dynamically linked programs) 3666 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 3667 */ 3668 struct tls_tcb * 3669 allocate_tls(Obj_Entry *objs) 3670 { 3671 Obj_Entry *obj; 3672 size_t data_size; 3673 size_t dtv_size; 3674 struct tls_tcb *tcb; 3675 Elf_Addr *dtv; 3676 Elf_Addr addr; 3677 3678 /* 3679 * Allocate the new TCB. static TLS storage is placed just before the 3680 * TCB to support the %gs:OFFSET (negative offset) model. 3681 */ 3682 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 3683 ~RTLD_STATIC_TLS_ALIGN_MASK; 3684 tcb = malloc(data_size + sizeof(*tcb)); 3685 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 3686 3687 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 3688 dtv = malloc(dtv_size); 3689 bzero(dtv, dtv_size); 3690 3691 #ifdef RTLD_TCB_HAS_SELF_POINTER 3692 tcb->tcb_self = tcb; 3693 #endif 3694 tcb->tcb_dtv = dtv; 3695 tcb->tcb_pthread = NULL; 3696 3697 dtv[0] = tls_dtv_generation; 3698 dtv[1] = tls_max_index; 3699 3700 for (obj = objs; obj; obj = obj->next) { 3701 if (obj->tlsoffset) { 3702 addr = (Elf_Addr)tcb - obj->tlsoffset; 3703 memset((void *)(addr + obj->tlsinitsize), 3704 0, obj->tlssize - obj->tlsinitsize); 3705 if (obj->tlsinit) 3706 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3707 dtv[obj->tlsindex + 1] = addr; 3708 } 3709 } 3710 return(tcb); 3711 } 3712 3713 void 3714 free_tls(struct tls_tcb *tcb) 3715 { 3716 Elf_Addr *dtv; 3717 int dtv_size, i; 3718 Elf_Addr tls_start, tls_end; 3719 size_t data_size; 3720 3721 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 3722 ~RTLD_STATIC_TLS_ALIGN_MASK; 3723 3724 dtv = tcb->tcb_dtv; 3725 dtv_size = dtv[1]; 3726 tls_end = (Elf_Addr)tcb; 3727 tls_start = (Elf_Addr)tcb - data_size; 3728 for (i = 0; i < dtv_size; i++) { 3729 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 3730 free((void *)dtv[i+2]); 3731 } 3732 } 3733 3734 free((void*) tls_start); 3735 } 3736 3737 #else 3738 #error "Unsupported TLS layout" 3739 #endif 3740 3741 /* 3742 * Allocate TLS block for module with given index. 3743 */ 3744 void * 3745 allocate_module_tls(int index) 3746 { 3747 Obj_Entry* obj; 3748 char* p; 3749 3750 for (obj = obj_list; obj; obj = obj->next) { 3751 if (obj->tlsindex == index) 3752 break; 3753 } 3754 if (!obj) { 3755 _rtld_error("Can't find module with TLS index %d", index); 3756 die(); 3757 } 3758 3759 p = malloc(obj->tlssize); 3760 if (p == NULL) { 3761 _rtld_error("Cannot allocate TLS block for index %d", index); 3762 die(); 3763 } 3764 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3765 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3766 3767 return p; 3768 } 3769 3770 bool 3771 allocate_tls_offset(Obj_Entry *obj) 3772 { 3773 size_t off; 3774 3775 if (obj->tls_done) 3776 return true; 3777 3778 if (obj->tlssize == 0) { 3779 obj->tls_done = true; 3780 return true; 3781 } 3782 3783 if (obj->tlsindex == 1) 3784 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3785 else 3786 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3787 obj->tlssize, obj->tlsalign); 3788 3789 /* 3790 * If we have already fixed the size of the static TLS block, we 3791 * must stay within that size. When allocating the static TLS, we 3792 * leave a small amount of space spare to be used for dynamically 3793 * loading modules which use static TLS. 3794 */ 3795 if (tls_static_space) { 3796 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3797 return false; 3798 } 3799 3800 tls_last_offset = obj->tlsoffset = off; 3801 tls_last_size = obj->tlssize; 3802 obj->tls_done = true; 3803 3804 return true; 3805 } 3806 3807 void 3808 free_tls_offset(Obj_Entry *obj) 3809 { 3810 #ifdef RTLD_STATIC_TLS_VARIANT_II 3811 /* 3812 * If we were the last thing to allocate out of the static TLS 3813 * block, we give our space back to the 'allocator'. This is a 3814 * simplistic workaround to allow libGL.so.1 to be loaded and 3815 * unloaded multiple times. We only handle the Variant II 3816 * mechanism for now - this really needs a proper allocator. 3817 */ 3818 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3819 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3820 tls_last_offset -= obj->tlssize; 3821 tls_last_size = 0; 3822 } 3823 #endif 3824 } 3825 3826 struct tls_tcb * 3827 _rtld_allocate_tls(void) 3828 { 3829 struct tls_tcb *new_tcb; 3830 RtldLockState lockstate; 3831 3832 wlock_acquire(rtld_bind_lock, &lockstate); 3833 new_tcb = allocate_tls(obj_list); 3834 lock_release(rtld_bind_lock, &lockstate); 3835 return (new_tcb); 3836 } 3837 3838 void 3839 _rtld_free_tls(struct tls_tcb *tcb) 3840 { 3841 RtldLockState lockstate; 3842 3843 wlock_acquire(rtld_bind_lock, &lockstate); 3844 free_tls(tcb); 3845 lock_release(rtld_bind_lock, &lockstate); 3846 } 3847 3848 static void 3849 object_add_name(Obj_Entry *obj, const char *name) 3850 { 3851 Name_Entry *entry; 3852 size_t len; 3853 3854 len = strlen(name); 3855 entry = malloc(sizeof(Name_Entry) + len); 3856 3857 if (entry != NULL) { 3858 strcpy(entry->name, name); 3859 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3860 } 3861 } 3862 3863 static int 3864 object_match_name(const Obj_Entry *obj, const char *name) 3865 { 3866 Name_Entry *entry; 3867 3868 STAILQ_FOREACH(entry, &obj->names, link) { 3869 if (strcmp(name, entry->name) == 0) 3870 return (1); 3871 } 3872 return (0); 3873 } 3874 3875 static Obj_Entry * 3876 locate_dependency(const Obj_Entry *obj, const char *name) 3877 { 3878 const Objlist_Entry *entry; 3879 const Needed_Entry *needed; 3880 3881 STAILQ_FOREACH(entry, &list_main, link) { 3882 if (object_match_name(entry->obj, name)) 3883 return entry->obj; 3884 } 3885 3886 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3887 if (strcmp(obj->strtab + needed->name, name) == 0 || 3888 (needed->obj != NULL && object_match_name(needed->obj, name))) { 3889 /* 3890 * If there is DT_NEEDED for the name we are looking for, 3891 * we are all set. Note that object might not be found if 3892 * dependency was not loaded yet, so the function can 3893 * return NULL here. This is expected and handled 3894 * properly by the caller. 3895 */ 3896 return (needed->obj); 3897 } 3898 } 3899 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3900 obj->path, name); 3901 die(); 3902 } 3903 3904 static int 3905 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3906 const Elf_Vernaux *vna) 3907 { 3908 const Elf_Verdef *vd; 3909 const char *vername; 3910 3911 vername = refobj->strtab + vna->vna_name; 3912 vd = depobj->verdef; 3913 if (vd == NULL) { 3914 _rtld_error("%s: version %s required by %s not defined", 3915 depobj->path, vername, refobj->path); 3916 return (-1); 3917 } 3918 for (;;) { 3919 if (vd->vd_version != VER_DEF_CURRENT) { 3920 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3921 depobj->path, vd->vd_version); 3922 return (-1); 3923 } 3924 if (vna->vna_hash == vd->vd_hash) { 3925 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3926 ((char *)vd + vd->vd_aux); 3927 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3928 return (0); 3929 } 3930 if (vd->vd_next == 0) 3931 break; 3932 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3933 } 3934 if (vna->vna_flags & VER_FLG_WEAK) 3935 return (0); 3936 _rtld_error("%s: version %s required by %s not found", 3937 depobj->path, vername, refobj->path); 3938 return (-1); 3939 } 3940 3941 static int 3942 rtld_verify_object_versions(Obj_Entry *obj) 3943 { 3944 const Elf_Verneed *vn; 3945 const Elf_Verdef *vd; 3946 const Elf_Verdaux *vda; 3947 const Elf_Vernaux *vna; 3948 const Obj_Entry *depobj; 3949 int maxvernum, vernum; 3950 3951 maxvernum = 0; 3952 /* 3953 * Walk over defined and required version records and figure out 3954 * max index used by any of them. Do very basic sanity checking 3955 * while there. 3956 */ 3957 vn = obj->verneed; 3958 while (vn != NULL) { 3959 if (vn->vn_version != VER_NEED_CURRENT) { 3960 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3961 obj->path, vn->vn_version); 3962 return (-1); 3963 } 3964 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3965 for (;;) { 3966 vernum = VER_NEED_IDX(vna->vna_other); 3967 if (vernum > maxvernum) 3968 maxvernum = vernum; 3969 if (vna->vna_next == 0) 3970 break; 3971 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3972 } 3973 if (vn->vn_next == 0) 3974 break; 3975 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3976 } 3977 3978 vd = obj->verdef; 3979 while (vd != NULL) { 3980 if (vd->vd_version != VER_DEF_CURRENT) { 3981 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3982 obj->path, vd->vd_version); 3983 return (-1); 3984 } 3985 vernum = VER_DEF_IDX(vd->vd_ndx); 3986 if (vernum > maxvernum) 3987 maxvernum = vernum; 3988 if (vd->vd_next == 0) 3989 break; 3990 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3991 } 3992 3993 if (maxvernum == 0) 3994 return (0); 3995 3996 /* 3997 * Store version information in array indexable by version index. 3998 * Verify that object version requirements are satisfied along the 3999 * way. 4000 */ 4001 obj->vernum = maxvernum + 1; 4002 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 4003 4004 vd = obj->verdef; 4005 while (vd != NULL) { 4006 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4007 vernum = VER_DEF_IDX(vd->vd_ndx); 4008 assert(vernum <= maxvernum); 4009 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4010 obj->vertab[vernum].hash = vd->vd_hash; 4011 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4012 obj->vertab[vernum].file = NULL; 4013 obj->vertab[vernum].flags = 0; 4014 } 4015 if (vd->vd_next == 0) 4016 break; 4017 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4018 } 4019 4020 vn = obj->verneed; 4021 while (vn != NULL) { 4022 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4023 if (depobj == NULL) 4024 return (-1); 4025 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4026 for (;;) { 4027 if (check_object_provided_version(obj, depobj, vna)) 4028 return (-1); 4029 vernum = VER_NEED_IDX(vna->vna_other); 4030 assert(vernum <= maxvernum); 4031 obj->vertab[vernum].hash = vna->vna_hash; 4032 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4033 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4034 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4035 VER_INFO_HIDDEN : 0; 4036 if (vna->vna_next == 0) 4037 break; 4038 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4039 } 4040 if (vn->vn_next == 0) 4041 break; 4042 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4043 } 4044 return 0; 4045 } 4046 4047 static int 4048 rtld_verify_versions(const Objlist *objlist) 4049 { 4050 Objlist_Entry *entry; 4051 int rc; 4052 4053 rc = 0; 4054 STAILQ_FOREACH(entry, objlist, link) { 4055 /* 4056 * Skip dummy objects or objects that have their version requirements 4057 * already checked. 4058 */ 4059 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4060 continue; 4061 if (rtld_verify_object_versions(entry->obj) == -1) { 4062 rc = -1; 4063 if (ld_tracing == NULL) 4064 break; 4065 } 4066 } 4067 if (rc == 0 || ld_tracing != NULL) 4068 rc = rtld_verify_object_versions(&obj_rtld); 4069 return rc; 4070 } 4071 4072 const Ver_Entry * 4073 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4074 { 4075 Elf_Versym vernum; 4076 4077 if (obj->vertab) { 4078 vernum = VER_NDX(obj->versyms[symnum]); 4079 if (vernum >= obj->vernum) { 4080 _rtld_error("%s: symbol %s has wrong verneed value %d", 4081 obj->path, obj->strtab + symnum, vernum); 4082 } else if (obj->vertab[vernum].hash != 0) { 4083 return &obj->vertab[vernum]; 4084 } 4085 } 4086 return NULL; 4087 } 4088 4089 int 4090 _rtld_get_stack_prot(void) 4091 { 4092 4093 return (stack_prot); 4094 } 4095 4096 static void 4097 map_stacks_exec(RtldLockState *lockstate) 4098 { 4099 return; 4100 /* 4101 * Stack protection must be implemented in the kernel before the dynamic 4102 * linker can handle PT_GNU_STACK sections. 4103 * The following is the FreeBSD implementation of map_stacks_exec() 4104 * void (*thr_map_stacks_exec)(void); 4105 * 4106 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4107 * return; 4108 * thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4109 * get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4110 * if (thr_map_stacks_exec != NULL) { 4111 * stack_prot |= PROT_EXEC; 4112 * thr_map_stacks_exec(); 4113 * } 4114 */ 4115 } 4116 4117 void 4118 symlook_init(SymLook *dst, const char *name) 4119 { 4120 4121 bzero(dst, sizeof(*dst)); 4122 dst->name = name; 4123 dst->hash = elf_hash(name); 4124 } 4125 4126 static void 4127 symlook_init_from_req(SymLook *dst, const SymLook *src) 4128 { 4129 4130 dst->name = src->name; 4131 dst->hash = src->hash; 4132 dst->ventry = src->ventry; 4133 dst->flags = src->flags; 4134 dst->defobj_out = NULL; 4135 dst->sym_out = NULL; 4136 dst->lockstate = src->lockstate; 4137 } 4138 4139 #ifdef ENABLE_OSRELDATE 4140 /* 4141 * Overrides for libc_pic-provided functions. 4142 */ 4143 4144 int 4145 __getosreldate(void) 4146 { 4147 size_t len; 4148 int oid[2]; 4149 int error, osrel; 4150 4151 if (osreldate != 0) 4152 return (osreldate); 4153 4154 oid[0] = CTL_KERN; 4155 oid[1] = KERN_OSRELDATE; 4156 osrel = 0; 4157 len = sizeof(osrel); 4158 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4159 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4160 osreldate = osrel; 4161 return (osreldate); 4162 } 4163 #endif 4164 4165 /* 4166 * No unresolved symbols for rtld. 4167 */ 4168 void 4169 __pthread_cxa_finalize(struct dl_phdr_info *a) 4170 { 4171 } 4172