1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mount.h> 42 #include <sys/mman.h> 43 #include <sys/stat.h> 44 #include <sys/sysctl.h> 45 #include <sys/uio.h> 46 #include <sys/utsname.h> 47 #include <sys/ktrace.h> 48 49 #include <dlfcn.h> 50 #include <err.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 #include "debug.h" 60 #include "rtld.h" 61 #include "libmap.h" 62 #include "rtld_tls.h" 63 #include "rtld_printf.h" 64 65 #ifndef COMPAT_32BIT 66 #define PATH_RTLD "/libexec/ld-elf.so.1" 67 #else 68 #define PATH_RTLD "/libexec/ld-elf32.so.1" 69 #endif 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 *basename(const char *); 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 void linkmap_add(Obj_Entry *); 101 static void linkmap_delete(Obj_Entry *); 102 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 103 static void unload_filtees(Obj_Entry *); 104 static int load_needed_objects(Obj_Entry *, int); 105 static int load_preload_objects(void); 106 static Obj_Entry *load_object(const char *, const Obj_Entry *, int); 107 static void map_stacks_exec(RtldLockState *); 108 static Obj_Entry *obj_from_addr(const void *); 109 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 110 static void objlist_call_init(Objlist *, RtldLockState *); 111 static void objlist_clear(Objlist *); 112 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 113 static void objlist_init(Objlist *); 114 static void objlist_push_head(Objlist *, Obj_Entry *); 115 static void objlist_push_tail(Objlist *, Obj_Entry *); 116 static void objlist_remove(Objlist *, Obj_Entry *); 117 static void *path_enumerate(const char *, path_enum_proc, void *); 118 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *); 119 static int rtld_dirname(const char *, char *); 120 static int rtld_dirname_abs(const char *, char *); 121 static void rtld_exit(void); 122 static char *search_library_path(const char *, const char *); 123 static const void **get_program_var_addr(const char *, RtldLockState *); 124 static void set_program_var(const char *, const void *); 125 static int symlook_default(SymLook *, const Obj_Entry *refobj); 126 static int symlook_global(SymLook *, DoneList *); 127 static void symlook_init_from_req(SymLook *, const SymLook *); 128 static int symlook_list(SymLook *, const Objlist *, DoneList *); 129 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 130 static int symlook_obj1(SymLook *, const Obj_Entry *); 131 static void trace_loaded_objects(Obj_Entry *); 132 static void unlink_object(Obj_Entry *); 133 static void unload_object(Obj_Entry *); 134 static void unref_dag(Obj_Entry *); 135 static void ref_dag(Obj_Entry *); 136 static int origin_subst_one(char **, const char *, const char *, 137 const char *, char *); 138 static char *origin_subst(const char *, const char *); 139 static int rtld_verify_versions(const Objlist *); 140 static int rtld_verify_object_versions(Obj_Entry *); 141 static void object_add_name(Obj_Entry *, const char *); 142 static int object_match_name(const Obj_Entry *, const char *); 143 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 144 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 145 struct dl_phdr_info *phdr_info); 146 147 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 148 149 /* 150 * Data declarations. 151 */ 152 static char *error_message; /* Message for dlerror(), or NULL */ 153 struct r_debug r_debug; /* for GDB; */ 154 static bool libmap_disable; /* Disable libmap */ 155 static bool ld_loadfltr; /* Immediate filters processing */ 156 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 157 static bool trust; /* False for setuid and setgid programs */ 158 static bool dangerous_ld_env; /* True if environment variables have been 159 used to affect the libraries loaded */ 160 static char *ld_bind_now; /* Environment variable for immediate binding */ 161 static char *ld_debug; /* Environment variable for debugging */ 162 static char *ld_library_path; /* Environment variable for search path */ 163 static char *ld_preload; /* Environment variable for libraries to 164 load first */ 165 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 166 static char *ld_tracing; /* Called from ldd to print libs */ 167 static char *ld_utrace; /* Use utrace() to log events. */ 168 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 169 static Obj_Entry **obj_tail; /* Link field of last object in list */ 170 static Obj_Entry *obj_main; /* The main program shared object */ 171 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 172 static unsigned int obj_count; /* Number of objects in obj_list */ 173 static unsigned int obj_loads; /* Number of objects in obj_list */ 174 175 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 176 STAILQ_HEAD_INITIALIZER(list_global); 177 static Objlist list_main = /* Objects loaded at program startup */ 178 STAILQ_HEAD_INITIALIZER(list_main); 179 static Objlist list_fini = /* Objects needing fini() calls */ 180 STAILQ_HEAD_INITIALIZER(list_fini); 181 182 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 183 184 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 185 186 extern Elf_Dyn _DYNAMIC; 187 #pragma weak _DYNAMIC 188 #ifndef RTLD_IS_DYNAMIC 189 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 190 #endif 191 192 int osreldate, pagesize; 193 194 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 195 static int max_stack_flags; 196 197 /* 198 * Global declarations normally provided by crt1. The dynamic linker is 199 * not built with crt1, so we have to provide them ourselves. 200 */ 201 char *__progname; 202 char **environ; 203 204 /* 205 * Globals to control TLS allocation. 206 */ 207 size_t tls_last_offset; /* Static TLS offset of last module */ 208 size_t tls_last_size; /* Static TLS size of last module */ 209 size_t tls_static_space; /* Static TLS space allocated */ 210 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 211 int tls_max_index = 1; /* Largest module index allocated */ 212 213 /* 214 * Fill in a DoneList with an allocation large enough to hold all of 215 * the currently-loaded objects. Keep this as a macro since it calls 216 * alloca and we want that to occur within the scope of the caller. 217 */ 218 #define donelist_init(dlp) \ 219 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 220 assert((dlp)->objs != NULL), \ 221 (dlp)->num_alloc = obj_count, \ 222 (dlp)->num_used = 0) 223 224 #define UTRACE_DLOPEN_START 1 225 #define UTRACE_DLOPEN_STOP 2 226 #define UTRACE_DLCLOSE_START 3 227 #define UTRACE_DLCLOSE_STOP 4 228 #define UTRACE_LOAD_OBJECT 5 229 #define UTRACE_UNLOAD_OBJECT 6 230 #define UTRACE_ADD_RUNDEP 7 231 #define UTRACE_PRELOAD_FINISHED 8 232 #define UTRACE_INIT_CALL 9 233 #define UTRACE_FINI_CALL 10 234 235 struct utrace_rtld { 236 char sig[4]; /* 'RTLD' */ 237 int event; 238 void *handle; 239 void *mapbase; /* Used for 'parent' and 'init/fini' */ 240 size_t mapsize; 241 int refcnt; /* Used for 'mode' */ 242 char name[MAXPATHLEN]; 243 }; 244 245 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 246 if (ld_utrace != NULL) \ 247 ld_utrace_log(e, h, mb, ms, r, n); \ 248 } while (0) 249 250 static void 251 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 252 int refcnt, const char *name) 253 { 254 struct utrace_rtld ut; 255 256 ut.sig[0] = 'R'; 257 ut.sig[1] = 'T'; 258 ut.sig[2] = 'L'; 259 ut.sig[3] = 'D'; 260 ut.event = event; 261 ut.handle = handle; 262 ut.mapbase = mapbase; 263 ut.mapsize = mapsize; 264 ut.refcnt = refcnt; 265 bzero(ut.name, sizeof(ut.name)); 266 if (name) 267 strlcpy(ut.name, name, sizeof(ut.name)); 268 utrace(&ut, sizeof(ut)); 269 } 270 271 /* 272 * Main entry point for dynamic linking. The first argument is the 273 * stack pointer. The stack is expected to be laid out as described 274 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 275 * Specifically, the stack pointer points to a word containing 276 * ARGC. Following that in the stack is a null-terminated sequence 277 * of pointers to argument strings. Then comes a null-terminated 278 * sequence of pointers to environment strings. Finally, there is a 279 * sequence of "auxiliary vector" entries. 280 * 281 * The second argument points to a place to store the dynamic linker's 282 * exit procedure pointer and the third to a place to store the main 283 * program's object. 284 * 285 * The return value is the main program's entry point. 286 */ 287 func_ptr_type 288 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 289 { 290 Elf_Auxinfo *aux_info[AT_COUNT]; 291 int i; 292 int argc; 293 char **argv; 294 char **env; 295 Elf_Auxinfo *aux; 296 Elf_Auxinfo *auxp; 297 const char *argv0; 298 Objlist_Entry *entry; 299 Obj_Entry *obj; 300 Obj_Entry **preload_tail; 301 Objlist initlist; 302 RtldLockState lockstate; 303 304 /* 305 * On entry, the dynamic linker itself has not been relocated yet. 306 * Be very careful not to reference any global data until after 307 * init_rtld has returned. It is OK to reference file-scope statics 308 * and string constants, and to call static and global functions. 309 */ 310 311 /* Find the auxiliary vector on the stack. */ 312 argc = *sp++; 313 argv = (char **) sp; 314 sp += argc + 1; /* Skip over arguments and NULL terminator */ 315 env = (char **) sp; 316 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 317 ; 318 aux = (Elf_Auxinfo *) sp; 319 320 /* Digest the auxiliary vector. */ 321 for (i = 0; i < AT_COUNT; i++) 322 aux_info[i] = NULL; 323 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 324 if (auxp->a_type < AT_COUNT) 325 aux_info[auxp->a_type] = auxp; 326 } 327 328 /* Initialize and relocate ourselves. */ 329 assert(aux_info[AT_BASE] != NULL); 330 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 331 332 __progname = obj_rtld.path; 333 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 334 environ = env; 335 336 trust = !issetugid(); 337 338 ld_bind_now = getenv(LD_ "BIND_NOW"); 339 /* 340 * If the process is tainted, then we un-set the dangerous environment 341 * variables. The process will be marked as tainted until setuid(2) 342 * is called. If any child process calls setuid(2) we do not want any 343 * future processes to honor the potentially un-safe variables. 344 */ 345 if (!trust) { 346 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 347 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 348 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 349 unsetenv(LD_ "LOADFLTR")) { 350 _rtld_error("environment corrupt; aborting"); 351 die(); 352 } 353 } 354 ld_debug = getenv(LD_ "DEBUG"); 355 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 356 libmap_override = getenv(LD_ "LIBMAP"); 357 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 358 ld_preload = getenv(LD_ "PRELOAD"); 359 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 360 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 361 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 362 (ld_library_path != NULL) || (ld_preload != NULL) || 363 (ld_elf_hints_path != NULL) || ld_loadfltr; 364 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 365 ld_utrace = getenv(LD_ "UTRACE"); 366 367 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 368 ld_elf_hints_path = _PATH_ELF_HINTS; 369 370 if (ld_debug != NULL && *ld_debug != '\0') 371 debug = 1; 372 dbg("%s is initialized, base address = %p", __progname, 373 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 374 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 375 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 376 377 dbg("initializing thread locks"); 378 lockdflt_init(); 379 380 /* 381 * Load the main program, or process its program header if it is 382 * already loaded. 383 */ 384 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 385 int fd = aux_info[AT_EXECFD]->a_un.a_val; 386 dbg("loading main program"); 387 obj_main = map_object(fd, argv0, NULL); 388 close(fd); 389 if (obj_main == NULL) 390 die(); 391 max_stack_flags = obj->stack_flags; 392 } else { /* Main program already loaded. */ 393 const Elf_Phdr *phdr; 394 int phnum; 395 caddr_t entry; 396 397 dbg("processing main program's program header"); 398 assert(aux_info[AT_PHDR] != NULL); 399 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 400 assert(aux_info[AT_PHNUM] != NULL); 401 phnum = aux_info[AT_PHNUM]->a_un.a_val; 402 assert(aux_info[AT_PHENT] != NULL); 403 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 404 assert(aux_info[AT_ENTRY] != NULL); 405 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 406 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 407 die(); 408 } 409 410 if (aux_info[AT_EXECPATH] != 0) { 411 char *kexecpath; 412 char buf[MAXPATHLEN]; 413 414 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 415 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 416 if (kexecpath[0] == '/') 417 obj_main->path = kexecpath; 418 else if (getcwd(buf, sizeof(buf)) == NULL || 419 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 420 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 421 obj_main->path = xstrdup(argv0); 422 else 423 obj_main->path = xstrdup(buf); 424 } else { 425 dbg("No AT_EXECPATH"); 426 obj_main->path = xstrdup(argv0); 427 } 428 dbg("obj_main path %s", obj_main->path); 429 obj_main->mainprog = true; 430 431 if (aux_info[AT_STACKPROT] != NULL && 432 aux_info[AT_STACKPROT]->a_un.a_val != 0) 433 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 434 435 /* 436 * Get the actual dynamic linker pathname from the executable if 437 * possible. (It should always be possible.) That ensures that 438 * gdb will find the right dynamic linker even if a non-standard 439 * one is being used. 440 */ 441 if (obj_main->interp != NULL && 442 strcmp(obj_main->interp, obj_rtld.path) != 0) { 443 free(obj_rtld.path); 444 obj_rtld.path = xstrdup(obj_main->interp); 445 __progname = obj_rtld.path; 446 } 447 448 digest_dynamic(obj_main, 0); 449 450 linkmap_add(obj_main); 451 linkmap_add(&obj_rtld); 452 453 /* Link the main program into the list of objects. */ 454 *obj_tail = obj_main; 455 obj_tail = &obj_main->next; 456 obj_count++; 457 obj_loads++; 458 /* Make sure we don't call the main program's init and fini functions. */ 459 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 460 461 /* Initialize a fake symbol for resolving undefined weak references. */ 462 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 463 sym_zero.st_shndx = SHN_UNDEF; 464 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 465 466 if (!libmap_disable) 467 libmap_disable = (bool)lm_init(libmap_override); 468 469 dbg("loading LD_PRELOAD libraries"); 470 if (load_preload_objects() == -1) 471 die(); 472 preload_tail = obj_tail; 473 474 dbg("loading needed objects"); 475 if (load_needed_objects(obj_main, 0) == -1) 476 die(); 477 478 /* Make a list of all objects loaded at startup. */ 479 for (obj = obj_list; obj != NULL; obj = obj->next) { 480 objlist_push_tail(&list_main, obj); 481 obj->refcount++; 482 } 483 484 dbg("checking for required versions"); 485 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 486 die(); 487 488 if (ld_tracing) { /* We're done */ 489 trace_loaded_objects(obj_main); 490 exit(0); 491 } 492 493 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 494 dump_relocations(obj_main); 495 exit (0); 496 } 497 498 /* 499 * Processing tls relocations requires having the tls offsets 500 * initialized. Prepare offsets before starting initial 501 * relocation processing. 502 */ 503 dbg("initializing initial thread local storage offsets"); 504 STAILQ_FOREACH(entry, &list_main, link) { 505 /* 506 * Allocate all the initial objects out of the static TLS 507 * block even if they didn't ask for it. 508 */ 509 allocate_tls_offset(entry->obj); 510 } 511 512 if (relocate_objects(obj_main, 513 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1) 514 die(); 515 516 dbg("doing copy relocations"); 517 if (do_copy_relocations(obj_main) == -1) 518 die(); 519 520 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 521 dump_relocations(obj_main); 522 exit (0); 523 } 524 525 /* 526 * Setup TLS for main thread. This must be done after the 527 * relocations are processed, since tls initialization section 528 * might be the subject for relocations. 529 */ 530 dbg("initializing initial thread local storage"); 531 allocate_initial_tls(obj_list); 532 533 dbg("initializing key program variables"); 534 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 535 set_program_var("environ", env); 536 set_program_var("__elf_aux_vector", aux); 537 538 /* Make a list of init functions to call. */ 539 objlist_init(&initlist); 540 initlist_add_objects(obj_list, preload_tail, &initlist); 541 542 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 543 544 map_stacks_exec(NULL); 545 546 wlock_acquire(rtld_bind_lock, &lockstate); 547 objlist_call_init(&initlist, &lockstate); 548 objlist_clear(&initlist); 549 dbg("loading filtees"); 550 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 551 if (ld_loadfltr || obj->z_loadfltr) 552 load_filtees(obj, 0, &lockstate); 553 } 554 lock_release(rtld_bind_lock, &lockstate); 555 556 dbg("transferring control to program entry point = %p", obj_main->entry); 557 558 /* Return the exit procedure and the program entry point. */ 559 *exit_proc = rtld_exit; 560 *objp = obj_main; 561 return (func_ptr_type) obj_main->entry; 562 } 563 564 void * 565 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 566 { 567 void *ptr; 568 Elf_Addr target; 569 570 ptr = (void *)make_function_pointer(def, obj); 571 target = ((Elf_Addr (*)(void))ptr)(); 572 return ((void *)target); 573 } 574 575 Elf_Addr 576 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 577 { 578 const Elf_Rel *rel; 579 const Elf_Sym *def; 580 const Obj_Entry *defobj; 581 Elf_Addr *where; 582 Elf_Addr target; 583 RtldLockState lockstate; 584 585 rlock_acquire(rtld_bind_lock, &lockstate); 586 if (sigsetjmp(lockstate.env, 0) != 0) 587 lock_upgrade(rtld_bind_lock, &lockstate); 588 if (obj->pltrel) 589 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 590 else 591 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 592 593 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 594 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 595 &lockstate); 596 if (def == NULL) 597 die(); 598 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 599 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 600 else 601 target = (Elf_Addr)(defobj->relocbase + def->st_value); 602 603 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 604 defobj->strtab + def->st_name, basename(obj->path), 605 (void *)target, basename(defobj->path)); 606 607 /* 608 * Write the new contents for the jmpslot. Note that depending on 609 * architecture, the value which we need to return back to the 610 * lazy binding trampoline may or may not be the target 611 * address. The value returned from reloc_jmpslot() is the value 612 * that the trampoline needs. 613 */ 614 target = reloc_jmpslot(where, target, defobj, obj, rel); 615 lock_release(rtld_bind_lock, &lockstate); 616 return target; 617 } 618 619 /* 620 * Error reporting function. Use it like printf. If formats the message 621 * into a buffer, and sets things up so that the next call to dlerror() 622 * will return the message. 623 */ 624 void 625 _rtld_error(const char *fmt, ...) 626 { 627 static char buf[512]; 628 va_list ap; 629 630 va_start(ap, fmt); 631 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 632 error_message = buf; 633 va_end(ap); 634 } 635 636 /* 637 * Return a dynamically-allocated copy of the current error message, if any. 638 */ 639 static char * 640 errmsg_save(void) 641 { 642 return error_message == NULL ? NULL : xstrdup(error_message); 643 } 644 645 /* 646 * Restore the current error message from a copy which was previously saved 647 * by errmsg_save(). The copy is freed. 648 */ 649 static void 650 errmsg_restore(char *saved_msg) 651 { 652 if (saved_msg == NULL) 653 error_message = NULL; 654 else { 655 _rtld_error("%s", saved_msg); 656 free(saved_msg); 657 } 658 } 659 660 static const char * 661 basename(const char *name) 662 { 663 const char *p = strrchr(name, '/'); 664 return p != NULL ? p + 1 : name; 665 } 666 667 static struct utsname uts; 668 669 static int 670 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 671 char *may_free) 672 { 673 const char *p, *p1; 674 char *res1; 675 int subst_len; 676 int kw_len; 677 678 res1 = *res = NULL; 679 p = real; 680 subst_len = kw_len = 0; 681 for (;;) { 682 p1 = strstr(p, kw); 683 if (p1 != NULL) { 684 if (subst_len == 0) { 685 subst_len = strlen(subst); 686 kw_len = strlen(kw); 687 } 688 if (*res == NULL) { 689 *res = xmalloc(PATH_MAX); 690 res1 = *res; 691 } 692 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 693 _rtld_error("Substitution of %s in %s cannot be performed", 694 kw, real); 695 if (may_free != NULL) 696 free(may_free); 697 free(res); 698 return (false); 699 } 700 memcpy(res1, p, p1 - p); 701 res1 += p1 - p; 702 memcpy(res1, subst, subst_len); 703 res1 += subst_len; 704 p = p1 + kw_len; 705 } else { 706 if (*res == NULL) { 707 if (may_free != NULL) 708 *res = may_free; 709 else 710 *res = xstrdup(real); 711 return (true); 712 } 713 *res1 = '\0'; 714 if (may_free != NULL) 715 free(may_free); 716 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 717 free(res); 718 return (false); 719 } 720 return (true); 721 } 722 } 723 } 724 725 static char * 726 origin_subst(const char *real, const char *origin_path) 727 { 728 char *res1, *res2, *res3, *res4; 729 730 if (uts.sysname[0] == '\0') { 731 if (uname(&uts) != 0) { 732 _rtld_error("utsname failed: %d", errno); 733 return (NULL); 734 } 735 } 736 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 737 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 738 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 739 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 740 return (NULL); 741 return (res4); 742 } 743 744 static void 745 die(void) 746 { 747 const char *msg = dlerror(); 748 749 if (msg == NULL) 750 msg = "Fatal error"; 751 rtld_fdputstr(STDERR_FILENO, msg); 752 _exit(1); 753 } 754 755 /* 756 * Process a shared object's DYNAMIC section, and save the important 757 * information in its Obj_Entry structure. 758 */ 759 static void 760 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 761 const Elf_Dyn **dyn_soname) 762 { 763 const Elf_Dyn *dynp; 764 Needed_Entry **needed_tail = &obj->needed; 765 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 766 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 767 int plttype = DT_REL; 768 769 *dyn_rpath = NULL; 770 *dyn_soname = NULL; 771 772 obj->bind_now = false; 773 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 774 switch (dynp->d_tag) { 775 776 case DT_REL: 777 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 778 break; 779 780 case DT_RELSZ: 781 obj->relsize = dynp->d_un.d_val; 782 break; 783 784 case DT_RELENT: 785 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 786 break; 787 788 case DT_JMPREL: 789 obj->pltrel = (const Elf_Rel *) 790 (obj->relocbase + dynp->d_un.d_ptr); 791 break; 792 793 case DT_PLTRELSZ: 794 obj->pltrelsize = dynp->d_un.d_val; 795 break; 796 797 case DT_RELA: 798 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 799 break; 800 801 case DT_RELASZ: 802 obj->relasize = dynp->d_un.d_val; 803 break; 804 805 case DT_RELAENT: 806 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 807 break; 808 809 case DT_PLTREL: 810 plttype = dynp->d_un.d_val; 811 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 812 break; 813 814 case DT_SYMTAB: 815 obj->symtab = (const Elf_Sym *) 816 (obj->relocbase + dynp->d_un.d_ptr); 817 break; 818 819 case DT_SYMENT: 820 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 821 break; 822 823 case DT_STRTAB: 824 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 825 break; 826 827 case DT_STRSZ: 828 obj->strsize = dynp->d_un.d_val; 829 break; 830 831 case DT_VERNEED: 832 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 833 dynp->d_un.d_val); 834 break; 835 836 case DT_VERNEEDNUM: 837 obj->verneednum = dynp->d_un.d_val; 838 break; 839 840 case DT_VERDEF: 841 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 842 dynp->d_un.d_val); 843 break; 844 845 case DT_VERDEFNUM: 846 obj->verdefnum = dynp->d_un.d_val; 847 break; 848 849 case DT_VERSYM: 850 obj->versyms = (const Elf_Versym *)(obj->relocbase + 851 dynp->d_un.d_val); 852 break; 853 854 case DT_HASH: 855 { 856 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 857 (obj->relocbase + dynp->d_un.d_ptr); 858 obj->nbuckets = hashtab[0]; 859 obj->nchains = hashtab[1]; 860 obj->buckets = hashtab + 2; 861 obj->chains = obj->buckets + obj->nbuckets; 862 } 863 break; 864 865 case DT_NEEDED: 866 if (!obj->rtld) { 867 Needed_Entry *nep = NEW(Needed_Entry); 868 nep->name = dynp->d_un.d_val; 869 nep->obj = NULL; 870 nep->next = NULL; 871 872 *needed_tail = nep; 873 needed_tail = &nep->next; 874 } 875 break; 876 877 case DT_FILTER: 878 if (!obj->rtld) { 879 Needed_Entry *nep = NEW(Needed_Entry); 880 nep->name = dynp->d_un.d_val; 881 nep->obj = NULL; 882 nep->next = NULL; 883 884 *needed_filtees_tail = nep; 885 needed_filtees_tail = &nep->next; 886 } 887 break; 888 889 case DT_AUXILIARY: 890 if (!obj->rtld) { 891 Needed_Entry *nep = NEW(Needed_Entry); 892 nep->name = dynp->d_un.d_val; 893 nep->obj = NULL; 894 nep->next = NULL; 895 896 *needed_aux_filtees_tail = nep; 897 needed_aux_filtees_tail = &nep->next; 898 } 899 break; 900 901 case DT_PLTGOT: 902 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 903 break; 904 905 case DT_TEXTREL: 906 obj->textrel = true; 907 break; 908 909 case DT_SYMBOLIC: 910 obj->symbolic = true; 911 break; 912 913 case DT_RPATH: 914 case DT_RUNPATH: /* XXX: process separately */ 915 /* 916 * We have to wait until later to process this, because we 917 * might not have gotten the address of the string table yet. 918 */ 919 *dyn_rpath = dynp; 920 break; 921 922 case DT_SONAME: 923 *dyn_soname = dynp; 924 break; 925 926 case DT_INIT: 927 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 928 break; 929 930 case DT_FINI: 931 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 932 break; 933 934 /* 935 * Don't process DT_DEBUG on MIPS as the dynamic section 936 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 937 */ 938 939 #ifndef __mips__ 940 case DT_DEBUG: 941 /* XXX - not implemented yet */ 942 if (!early) 943 dbg("Filling in DT_DEBUG entry"); 944 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 945 break; 946 #endif 947 948 case DT_FLAGS: 949 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 950 obj->z_origin = true; 951 if (dynp->d_un.d_val & DF_SYMBOLIC) 952 obj->symbolic = true; 953 if (dynp->d_un.d_val & DF_TEXTREL) 954 obj->textrel = true; 955 if (dynp->d_un.d_val & DF_BIND_NOW) 956 obj->bind_now = true; 957 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 958 ;*/ 959 break; 960 #ifdef __mips__ 961 case DT_MIPS_LOCAL_GOTNO: 962 obj->local_gotno = dynp->d_un.d_val; 963 break; 964 965 case DT_MIPS_SYMTABNO: 966 obj->symtabno = dynp->d_un.d_val; 967 break; 968 969 case DT_MIPS_GOTSYM: 970 obj->gotsym = dynp->d_un.d_val; 971 break; 972 973 case DT_MIPS_RLD_MAP: 974 #ifdef notyet 975 if (!early) 976 dbg("Filling in DT_DEBUG entry"); 977 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 978 #endif 979 break; 980 #endif 981 982 case DT_FLAGS_1: 983 if (dynp->d_un.d_val & DF_1_NOOPEN) 984 obj->z_noopen = true; 985 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 986 obj->z_origin = true; 987 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 988 XXX ;*/ 989 if (dynp->d_un.d_val & DF_1_BIND_NOW) 990 obj->bind_now = true; 991 if (dynp->d_un.d_val & DF_1_NODELETE) 992 obj->z_nodelete = true; 993 if (dynp->d_un.d_val & DF_1_LOADFLTR) 994 obj->z_loadfltr = true; 995 break; 996 997 default: 998 if (!early) { 999 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1000 (long)dynp->d_tag); 1001 } 1002 break; 1003 } 1004 } 1005 1006 obj->traced = false; 1007 1008 if (plttype == DT_RELA) { 1009 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1010 obj->pltrel = NULL; 1011 obj->pltrelasize = obj->pltrelsize; 1012 obj->pltrelsize = 0; 1013 } 1014 } 1015 1016 static void 1017 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1018 const Elf_Dyn *dyn_soname) 1019 { 1020 1021 if (obj->z_origin && obj->origin_path == NULL) { 1022 obj->origin_path = xmalloc(PATH_MAX); 1023 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1024 die(); 1025 } 1026 1027 if (dyn_rpath != NULL) { 1028 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1029 if (obj->z_origin) 1030 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1031 } 1032 1033 if (dyn_soname != NULL) 1034 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1035 } 1036 1037 static void 1038 digest_dynamic(Obj_Entry *obj, int early) 1039 { 1040 const Elf_Dyn *dyn_rpath; 1041 const Elf_Dyn *dyn_soname; 1042 1043 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1044 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1045 } 1046 1047 /* 1048 * Process a shared object's program header. This is used only for the 1049 * main program, when the kernel has already loaded the main program 1050 * into memory before calling the dynamic linker. It creates and 1051 * returns an Obj_Entry structure. 1052 */ 1053 static Obj_Entry * 1054 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1055 { 1056 Obj_Entry *obj; 1057 const Elf_Phdr *phlimit = phdr + phnum; 1058 const Elf_Phdr *ph; 1059 int nsegs = 0; 1060 1061 obj = obj_new(); 1062 for (ph = phdr; ph < phlimit; ph++) { 1063 if (ph->p_type != PT_PHDR) 1064 continue; 1065 1066 obj->phdr = phdr; 1067 obj->phsize = ph->p_memsz; 1068 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1069 break; 1070 } 1071 1072 obj->stack_flags = PF_X | PF_R | PF_W; 1073 1074 for (ph = phdr; ph < phlimit; ph++) { 1075 switch (ph->p_type) { 1076 1077 case PT_INTERP: 1078 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1079 break; 1080 1081 case PT_LOAD: 1082 if (nsegs == 0) { /* First load segment */ 1083 obj->vaddrbase = trunc_page(ph->p_vaddr); 1084 obj->mapbase = obj->vaddrbase + obj->relocbase; 1085 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1086 obj->vaddrbase; 1087 } else { /* Last load segment */ 1088 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1089 obj->vaddrbase; 1090 } 1091 nsegs++; 1092 break; 1093 1094 case PT_DYNAMIC: 1095 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1096 break; 1097 1098 case PT_TLS: 1099 obj->tlsindex = 1; 1100 obj->tlssize = ph->p_memsz; 1101 obj->tlsalign = ph->p_align; 1102 obj->tlsinitsize = ph->p_filesz; 1103 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1104 break; 1105 1106 case PT_GNU_STACK: 1107 obj->stack_flags = ph->p_flags; 1108 break; 1109 } 1110 } 1111 if (nsegs < 1) { 1112 _rtld_error("%s: too few PT_LOAD segments", path); 1113 return NULL; 1114 } 1115 1116 obj->entry = entry; 1117 return obj; 1118 } 1119 1120 static Obj_Entry * 1121 dlcheck(void *handle) 1122 { 1123 Obj_Entry *obj; 1124 1125 for (obj = obj_list; obj != NULL; obj = obj->next) 1126 if (obj == (Obj_Entry *) handle) 1127 break; 1128 1129 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1130 _rtld_error("Invalid shared object handle %p", handle); 1131 return NULL; 1132 } 1133 return obj; 1134 } 1135 1136 /* 1137 * If the given object is already in the donelist, return true. Otherwise 1138 * add the object to the list and return false. 1139 */ 1140 static bool 1141 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1142 { 1143 unsigned int i; 1144 1145 for (i = 0; i < dlp->num_used; i++) 1146 if (dlp->objs[i] == obj) 1147 return true; 1148 /* 1149 * Our donelist allocation should always be sufficient. But if 1150 * our threads locking isn't working properly, more shared objects 1151 * could have been loaded since we allocated the list. That should 1152 * never happen, but we'll handle it properly just in case it does. 1153 */ 1154 if (dlp->num_used < dlp->num_alloc) 1155 dlp->objs[dlp->num_used++] = obj; 1156 return false; 1157 } 1158 1159 /* 1160 * Hash function for symbol table lookup. Don't even think about changing 1161 * this. It is specified by the System V ABI. 1162 */ 1163 unsigned long 1164 elf_hash(const char *name) 1165 { 1166 const unsigned char *p = (const unsigned char *) name; 1167 unsigned long h = 0; 1168 unsigned long g; 1169 1170 while (*p != '\0') { 1171 h = (h << 4) + *p++; 1172 if ((g = h & 0xf0000000) != 0) 1173 h ^= g >> 24; 1174 h &= ~g; 1175 } 1176 return h; 1177 } 1178 1179 /* 1180 * Find the library with the given name, and return its full pathname. 1181 * The returned string is dynamically allocated. Generates an error 1182 * message and returns NULL if the library cannot be found. 1183 * 1184 * If the second argument is non-NULL, then it refers to an already- 1185 * loaded shared object, whose library search path will be searched. 1186 * 1187 * The search order is: 1188 * LD_LIBRARY_PATH 1189 * rpath in the referencing file 1190 * ldconfig hints 1191 * /lib:/usr/lib 1192 */ 1193 static char * 1194 find_library(const char *xname, const Obj_Entry *refobj) 1195 { 1196 char *pathname; 1197 char *name; 1198 1199 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1200 if (xname[0] != '/' && !trust) { 1201 _rtld_error("Absolute pathname required for shared object \"%s\"", 1202 xname); 1203 return NULL; 1204 } 1205 if (refobj != NULL && refobj->z_origin) 1206 return origin_subst(xname, refobj->origin_path); 1207 else 1208 return xstrdup(xname); 1209 } 1210 1211 if (libmap_disable || (refobj == NULL) || 1212 (name = lm_find(refobj->path, xname)) == NULL) 1213 name = (char *)xname; 1214 1215 dbg(" Searching for \"%s\"", name); 1216 1217 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1218 (refobj != NULL && 1219 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1220 (pathname = search_library_path(name, gethints())) != NULL || 1221 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1222 return pathname; 1223 1224 if(refobj != NULL && refobj->path != NULL) { 1225 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1226 name, basename(refobj->path)); 1227 } else { 1228 _rtld_error("Shared object \"%s\" not found", name); 1229 } 1230 return NULL; 1231 } 1232 1233 /* 1234 * Given a symbol number in a referencing object, find the corresponding 1235 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1236 * no definition was found. Returns a pointer to the Obj_Entry of the 1237 * defining object via the reference parameter DEFOBJ_OUT. 1238 */ 1239 const Elf_Sym * 1240 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1241 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1242 RtldLockState *lockstate) 1243 { 1244 const Elf_Sym *ref; 1245 const Elf_Sym *def; 1246 const Obj_Entry *defobj; 1247 SymLook req; 1248 const char *name; 1249 int res; 1250 1251 /* 1252 * If we have already found this symbol, get the information from 1253 * the cache. 1254 */ 1255 if (symnum >= refobj->nchains) 1256 return NULL; /* Bad object */ 1257 if (cache != NULL && cache[symnum].sym != NULL) { 1258 *defobj_out = cache[symnum].obj; 1259 return cache[symnum].sym; 1260 } 1261 1262 ref = refobj->symtab + symnum; 1263 name = refobj->strtab + ref->st_name; 1264 def = NULL; 1265 defobj = NULL; 1266 1267 /* 1268 * We don't have to do a full scale lookup if the symbol is local. 1269 * We know it will bind to the instance in this load module; to 1270 * which we already have a pointer (ie ref). By not doing a lookup, 1271 * we not only improve performance, but it also avoids unresolvable 1272 * symbols when local symbols are not in the hash table. This has 1273 * been seen with the ia64 toolchain. 1274 */ 1275 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1276 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1277 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1278 symnum); 1279 } 1280 symlook_init(&req, name); 1281 req.flags = flags; 1282 req.ventry = fetch_ventry(refobj, symnum); 1283 req.lockstate = lockstate; 1284 res = symlook_default(&req, refobj); 1285 if (res == 0) { 1286 def = req.sym_out; 1287 defobj = req.defobj_out; 1288 } 1289 } else { 1290 def = ref; 1291 defobj = refobj; 1292 } 1293 1294 /* 1295 * If we found no definition and the reference is weak, treat the 1296 * symbol as having the value zero. 1297 */ 1298 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1299 def = &sym_zero; 1300 defobj = obj_main; 1301 } 1302 1303 if (def != NULL) { 1304 *defobj_out = defobj; 1305 /* Record the information in the cache to avoid subsequent lookups. */ 1306 if (cache != NULL) { 1307 cache[symnum].sym = def; 1308 cache[symnum].obj = defobj; 1309 } 1310 } else { 1311 if (refobj != &obj_rtld) 1312 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1313 } 1314 return def; 1315 } 1316 1317 /* 1318 * Return the search path from the ldconfig hints file, reading it if 1319 * necessary. Returns NULL if there are problems with the hints file, 1320 * or if the search path there is empty. 1321 */ 1322 static const char * 1323 gethints(void) 1324 { 1325 static char *hints; 1326 1327 if (hints == NULL) { 1328 int fd; 1329 struct elfhints_hdr hdr; 1330 char *p; 1331 1332 /* Keep from trying again in case the hints file is bad. */ 1333 hints = ""; 1334 1335 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1336 return NULL; 1337 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1338 hdr.magic != ELFHINTS_MAGIC || 1339 hdr.version != 1) { 1340 close(fd); 1341 return NULL; 1342 } 1343 p = xmalloc(hdr.dirlistlen + 1); 1344 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1345 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1346 free(p); 1347 close(fd); 1348 return NULL; 1349 } 1350 hints = p; 1351 close(fd); 1352 } 1353 return hints[0] != '\0' ? hints : NULL; 1354 } 1355 1356 static void 1357 init_dag(Obj_Entry *root) 1358 { 1359 const Needed_Entry *needed; 1360 const Objlist_Entry *elm; 1361 DoneList donelist; 1362 1363 if (root->dag_inited) 1364 return; 1365 donelist_init(&donelist); 1366 1367 /* Root object belongs to own DAG. */ 1368 objlist_push_tail(&root->dldags, root); 1369 objlist_push_tail(&root->dagmembers, root); 1370 donelist_check(&donelist, root); 1371 1372 /* 1373 * Add dependencies of root object to DAG in breadth order 1374 * by exploiting the fact that each new object get added 1375 * to the tail of the dagmembers list. 1376 */ 1377 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1378 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1379 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1380 continue; 1381 objlist_push_tail(&needed->obj->dldags, root); 1382 objlist_push_tail(&root->dagmembers, needed->obj); 1383 } 1384 } 1385 root->dag_inited = true; 1386 } 1387 1388 /* 1389 * Initialize the dynamic linker. The argument is the address at which 1390 * the dynamic linker has been mapped into memory. The primary task of 1391 * this function is to relocate the dynamic linker. 1392 */ 1393 static void 1394 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1395 { 1396 Obj_Entry objtmp; /* Temporary rtld object */ 1397 const Elf_Dyn *dyn_rpath; 1398 const Elf_Dyn *dyn_soname; 1399 1400 /* 1401 * Conjure up an Obj_Entry structure for the dynamic linker. 1402 * 1403 * The "path" member can't be initialized yet because string constants 1404 * cannot yet be accessed. Below we will set it correctly. 1405 */ 1406 memset(&objtmp, 0, sizeof(objtmp)); 1407 objtmp.path = NULL; 1408 objtmp.rtld = true; 1409 objtmp.mapbase = mapbase; 1410 #ifdef PIC 1411 objtmp.relocbase = mapbase; 1412 #endif 1413 if (RTLD_IS_DYNAMIC()) { 1414 objtmp.dynamic = rtld_dynamic(&objtmp); 1415 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1416 assert(objtmp.needed == NULL); 1417 #if !defined(__mips__) 1418 /* MIPS has a bogus DT_TEXTREL. */ 1419 assert(!objtmp.textrel); 1420 #endif 1421 1422 /* 1423 * Temporarily put the dynamic linker entry into the object list, so 1424 * that symbols can be found. 1425 */ 1426 1427 relocate_objects(&objtmp, true, &objtmp, NULL); 1428 } 1429 1430 /* Initialize the object list. */ 1431 obj_tail = &obj_list; 1432 1433 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1434 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1435 1436 if (aux_info[AT_PAGESZ] != NULL) 1437 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1438 if (aux_info[AT_OSRELDATE] != NULL) 1439 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1440 1441 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1442 1443 /* Replace the path with a dynamically allocated copy. */ 1444 obj_rtld.path = xstrdup(PATH_RTLD); 1445 1446 r_debug.r_brk = r_debug_state; 1447 r_debug.r_state = RT_CONSISTENT; 1448 } 1449 1450 /* 1451 * Add the init functions from a needed object list (and its recursive 1452 * needed objects) to "list". This is not used directly; it is a helper 1453 * function for initlist_add_objects(). The write lock must be held 1454 * when this function is called. 1455 */ 1456 static void 1457 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1458 { 1459 /* Recursively process the successor needed objects. */ 1460 if (needed->next != NULL) 1461 initlist_add_neededs(needed->next, list); 1462 1463 /* Process the current needed object. */ 1464 if (needed->obj != NULL) 1465 initlist_add_objects(needed->obj, &needed->obj->next, list); 1466 } 1467 1468 /* 1469 * Scan all of the DAGs rooted in the range of objects from "obj" to 1470 * "tail" and add their init functions to "list". This recurses over 1471 * the DAGs and ensure the proper init ordering such that each object's 1472 * needed libraries are initialized before the object itself. At the 1473 * same time, this function adds the objects to the global finalization 1474 * list "list_fini" in the opposite order. The write lock must be 1475 * held when this function is called. 1476 */ 1477 static void 1478 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1479 { 1480 if (obj->init_scanned || obj->init_done) 1481 return; 1482 obj->init_scanned = true; 1483 1484 /* Recursively process the successor objects. */ 1485 if (&obj->next != tail) 1486 initlist_add_objects(obj->next, tail, list); 1487 1488 /* Recursively process the needed objects. */ 1489 if (obj->needed != NULL) 1490 initlist_add_neededs(obj->needed, list); 1491 1492 /* Add the object to the init list. */ 1493 if (obj->init != (Elf_Addr)NULL) 1494 objlist_push_tail(list, obj); 1495 1496 /* Add the object to the global fini list in the reverse order. */ 1497 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) { 1498 objlist_push_head(&list_fini, obj); 1499 obj->on_fini_list = true; 1500 } 1501 } 1502 1503 #ifndef FPTR_TARGET 1504 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1505 #endif 1506 1507 static void 1508 free_needed_filtees(Needed_Entry *n) 1509 { 1510 Needed_Entry *needed, *needed1; 1511 1512 for (needed = n; needed != NULL; needed = needed->next) { 1513 if (needed->obj != NULL) { 1514 dlclose(needed->obj); 1515 needed->obj = NULL; 1516 } 1517 } 1518 for (needed = n; needed != NULL; needed = needed1) { 1519 needed1 = needed->next; 1520 free(needed); 1521 } 1522 } 1523 1524 static void 1525 unload_filtees(Obj_Entry *obj) 1526 { 1527 1528 free_needed_filtees(obj->needed_filtees); 1529 obj->needed_filtees = NULL; 1530 free_needed_filtees(obj->needed_aux_filtees); 1531 obj->needed_aux_filtees = NULL; 1532 obj->filtees_loaded = false; 1533 } 1534 1535 static void 1536 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags) 1537 { 1538 1539 for (; needed != NULL; needed = needed->next) { 1540 needed->obj = dlopen_object(obj->strtab + needed->name, obj, 1541 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1542 RTLD_LOCAL); 1543 } 1544 } 1545 1546 static void 1547 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1548 { 1549 1550 lock_restart_for_upgrade(lockstate); 1551 if (!obj->filtees_loaded) { 1552 load_filtee1(obj, obj->needed_filtees, flags); 1553 load_filtee1(obj, obj->needed_aux_filtees, flags); 1554 obj->filtees_loaded = true; 1555 } 1556 } 1557 1558 static int 1559 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1560 { 1561 Obj_Entry *obj1; 1562 1563 for (; needed != NULL; needed = needed->next) { 1564 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj, 1565 flags & ~RTLD_LO_NOLOAD); 1566 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1567 return (-1); 1568 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1569 dbg("obj %s nodelete", obj1->path); 1570 init_dag(obj1); 1571 ref_dag(obj1); 1572 obj1->ref_nodel = true; 1573 } 1574 } 1575 return (0); 1576 } 1577 1578 /* 1579 * Given a shared object, traverse its list of needed objects, and load 1580 * each of them. Returns 0 on success. Generates an error message and 1581 * returns -1 on failure. 1582 */ 1583 static int 1584 load_needed_objects(Obj_Entry *first, int flags) 1585 { 1586 Obj_Entry *obj; 1587 1588 for (obj = first; obj != NULL; obj = obj->next) { 1589 if (process_needed(obj, obj->needed, flags) == -1) 1590 return (-1); 1591 } 1592 return (0); 1593 } 1594 1595 static int 1596 load_preload_objects(void) 1597 { 1598 char *p = ld_preload; 1599 static const char delim[] = " \t:;"; 1600 1601 if (p == NULL) 1602 return 0; 1603 1604 p += strspn(p, delim); 1605 while (*p != '\0') { 1606 size_t len = strcspn(p, delim); 1607 char savech; 1608 1609 savech = p[len]; 1610 p[len] = '\0'; 1611 if (load_object(p, NULL, 0) == NULL) 1612 return -1; /* XXX - cleanup */ 1613 p[len] = savech; 1614 p += len; 1615 p += strspn(p, delim); 1616 } 1617 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1618 return 0; 1619 } 1620 1621 /* 1622 * Load a shared object into memory, if it is not already loaded. 1623 * 1624 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1625 * on failure. 1626 */ 1627 static Obj_Entry * 1628 load_object(const char *name, const Obj_Entry *refobj, int flags) 1629 { 1630 Obj_Entry *obj; 1631 int fd = -1; 1632 struct stat sb; 1633 char *path; 1634 1635 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1636 if (object_match_name(obj, name)) 1637 return obj; 1638 1639 path = find_library(name, refobj); 1640 if (path == NULL) 1641 return NULL; 1642 1643 /* 1644 * If we didn't find a match by pathname, open the file and check 1645 * again by device and inode. This avoids false mismatches caused 1646 * by multiple links or ".." in pathnames. 1647 * 1648 * To avoid a race, we open the file and use fstat() rather than 1649 * using stat(). 1650 */ 1651 if ((fd = open(path, O_RDONLY)) == -1) { 1652 _rtld_error("Cannot open \"%s\"", path); 1653 free(path); 1654 return NULL; 1655 } 1656 if (fstat(fd, &sb) == -1) { 1657 _rtld_error("Cannot fstat \"%s\"", path); 1658 close(fd); 1659 free(path); 1660 return NULL; 1661 } 1662 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1663 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1664 break; 1665 if (obj != NULL) { 1666 object_add_name(obj, name); 1667 free(path); 1668 close(fd); 1669 return obj; 1670 } 1671 if (flags & RTLD_LO_NOLOAD) { 1672 free(path); 1673 close(fd); 1674 return (NULL); 1675 } 1676 1677 /* First use of this object, so we must map it in */ 1678 obj = do_load_object(fd, name, path, &sb, flags); 1679 if (obj == NULL) 1680 free(path); 1681 close(fd); 1682 1683 return obj; 1684 } 1685 1686 static Obj_Entry * 1687 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1688 int flags) 1689 { 1690 Obj_Entry *obj; 1691 struct statfs fs; 1692 1693 /* 1694 * but first, make sure that environment variables haven't been 1695 * used to circumvent the noexec flag on a filesystem. 1696 */ 1697 if (dangerous_ld_env) { 1698 if (fstatfs(fd, &fs) != 0) { 1699 _rtld_error("Cannot fstatfs \"%s\"", path); 1700 return NULL; 1701 } 1702 if (fs.f_flags & MNT_NOEXEC) { 1703 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1704 return NULL; 1705 } 1706 } 1707 dbg("loading \"%s\"", path); 1708 obj = map_object(fd, path, sbp); 1709 if (obj == NULL) 1710 return NULL; 1711 1712 object_add_name(obj, name); 1713 obj->path = path; 1714 digest_dynamic(obj, 0); 1715 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1716 RTLD_LO_DLOPEN) { 1717 dbg("refusing to load non-loadable \"%s\"", obj->path); 1718 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1719 munmap(obj->mapbase, obj->mapsize); 1720 obj_free(obj); 1721 return (NULL); 1722 } 1723 1724 *obj_tail = obj; 1725 obj_tail = &obj->next; 1726 obj_count++; 1727 obj_loads++; 1728 linkmap_add(obj); /* for GDB & dlinfo() */ 1729 max_stack_flags |= obj->stack_flags; 1730 1731 dbg(" %p .. %p: %s", obj->mapbase, 1732 obj->mapbase + obj->mapsize - 1, obj->path); 1733 if (obj->textrel) 1734 dbg(" WARNING: %s has impure text", obj->path); 1735 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1736 obj->path); 1737 1738 return obj; 1739 } 1740 1741 static Obj_Entry * 1742 obj_from_addr(const void *addr) 1743 { 1744 Obj_Entry *obj; 1745 1746 for (obj = obj_list; obj != NULL; obj = obj->next) { 1747 if (addr < (void *) obj->mapbase) 1748 continue; 1749 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1750 return obj; 1751 } 1752 return NULL; 1753 } 1754 1755 /* 1756 * Call the finalization functions for each of the objects in "list" 1757 * belonging to the DAG of "root" and referenced once. If NULL "root" 1758 * is specified, every finalization function will be called regardless 1759 * of the reference count and the list elements won't be freed. All of 1760 * the objects are expected to have non-NULL fini functions. 1761 */ 1762 static void 1763 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1764 { 1765 Objlist_Entry *elm; 1766 char *saved_msg; 1767 1768 assert(root == NULL || root->refcount == 1); 1769 1770 /* 1771 * Preserve the current error message since a fini function might 1772 * call into the dynamic linker and overwrite it. 1773 */ 1774 saved_msg = errmsg_save(); 1775 do { 1776 STAILQ_FOREACH(elm, list, link) { 1777 if (root != NULL && (elm->obj->refcount != 1 || 1778 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1779 continue; 1780 dbg("calling fini function for %s at %p", elm->obj->path, 1781 (void *)elm->obj->fini); 1782 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, 1783 elm->obj->path); 1784 /* Remove object from fini list to prevent recursive invocation. */ 1785 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1786 /* 1787 * XXX: If a dlopen() call references an object while the 1788 * fini function is in progress, we might end up trying to 1789 * unload the referenced object in dlclose() or the object 1790 * won't be unloaded although its fini function has been 1791 * called. 1792 */ 1793 lock_release(rtld_bind_lock, lockstate); 1794 call_initfini_pointer(elm->obj, elm->obj->fini); 1795 wlock_acquire(rtld_bind_lock, lockstate); 1796 /* No need to free anything if process is going down. */ 1797 if (root != NULL) 1798 free(elm); 1799 /* 1800 * We must restart the list traversal after every fini call 1801 * because a dlclose() call from the fini function or from 1802 * another thread might have modified the reference counts. 1803 */ 1804 break; 1805 } 1806 } while (elm != NULL); 1807 errmsg_restore(saved_msg); 1808 } 1809 1810 /* 1811 * Call the initialization functions for each of the objects in 1812 * "list". All of the objects are expected to have non-NULL init 1813 * functions. 1814 */ 1815 static void 1816 objlist_call_init(Objlist *list, RtldLockState *lockstate) 1817 { 1818 Objlist_Entry *elm; 1819 Obj_Entry *obj; 1820 char *saved_msg; 1821 1822 /* 1823 * Clean init_scanned flag so that objects can be rechecked and 1824 * possibly initialized earlier if any of vectors called below 1825 * cause the change by using dlopen. 1826 */ 1827 for (obj = obj_list; obj != NULL; obj = obj->next) 1828 obj->init_scanned = false; 1829 1830 /* 1831 * Preserve the current error message since an init function might 1832 * call into the dynamic linker and overwrite it. 1833 */ 1834 saved_msg = errmsg_save(); 1835 STAILQ_FOREACH(elm, list, link) { 1836 if (elm->obj->init_done) /* Initialized early. */ 1837 continue; 1838 dbg("calling init function for %s at %p", elm->obj->path, 1839 (void *)elm->obj->init); 1840 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, 1841 elm->obj->path); 1842 /* 1843 * Race: other thread might try to use this object before current 1844 * one completes the initilization. Not much can be done here 1845 * without better locking. 1846 */ 1847 elm->obj->init_done = true; 1848 lock_release(rtld_bind_lock, lockstate); 1849 call_initfini_pointer(elm->obj, elm->obj->init); 1850 wlock_acquire(rtld_bind_lock, lockstate); 1851 } 1852 errmsg_restore(saved_msg); 1853 } 1854 1855 static void 1856 objlist_clear(Objlist *list) 1857 { 1858 Objlist_Entry *elm; 1859 1860 while (!STAILQ_EMPTY(list)) { 1861 elm = STAILQ_FIRST(list); 1862 STAILQ_REMOVE_HEAD(list, link); 1863 free(elm); 1864 } 1865 } 1866 1867 static Objlist_Entry * 1868 objlist_find(Objlist *list, const Obj_Entry *obj) 1869 { 1870 Objlist_Entry *elm; 1871 1872 STAILQ_FOREACH(elm, list, link) 1873 if (elm->obj == obj) 1874 return elm; 1875 return NULL; 1876 } 1877 1878 static void 1879 objlist_init(Objlist *list) 1880 { 1881 STAILQ_INIT(list); 1882 } 1883 1884 static void 1885 objlist_push_head(Objlist *list, Obj_Entry *obj) 1886 { 1887 Objlist_Entry *elm; 1888 1889 elm = NEW(Objlist_Entry); 1890 elm->obj = obj; 1891 STAILQ_INSERT_HEAD(list, elm, link); 1892 } 1893 1894 static void 1895 objlist_push_tail(Objlist *list, Obj_Entry *obj) 1896 { 1897 Objlist_Entry *elm; 1898 1899 elm = NEW(Objlist_Entry); 1900 elm->obj = obj; 1901 STAILQ_INSERT_TAIL(list, elm, link); 1902 } 1903 1904 static void 1905 objlist_remove(Objlist *list, Obj_Entry *obj) 1906 { 1907 Objlist_Entry *elm; 1908 1909 if ((elm = objlist_find(list, obj)) != NULL) { 1910 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1911 free(elm); 1912 } 1913 } 1914 1915 /* 1916 * Relocate newly-loaded shared objects. The argument is a pointer to 1917 * the Obj_Entry for the first such object. All objects from the first 1918 * to the end of the list of objects are relocated. Returns 0 on success, 1919 * or -1 on failure. 1920 */ 1921 static int 1922 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 1923 RtldLockState *lockstate) 1924 { 1925 Obj_Entry *obj; 1926 1927 for (obj = first; obj != NULL; obj = obj->next) { 1928 if (obj != rtldobj) 1929 dbg("relocating \"%s\"", obj->path); 1930 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 1931 obj->symtab == NULL || obj->strtab == NULL) { 1932 _rtld_error("%s: Shared object has no run-time symbol table", 1933 obj->path); 1934 return -1; 1935 } 1936 1937 if (obj->textrel) { 1938 /* There are relocations to the write-protected text segment. */ 1939 if (mprotect(obj->mapbase, obj->textsize, 1940 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 1941 _rtld_error("%s: Cannot write-enable text segment: %s", 1942 obj->path, strerror(errno)); 1943 return -1; 1944 } 1945 } 1946 1947 /* Process the non-PLT relocations. */ 1948 if (reloc_non_plt(obj, rtldobj, lockstate)) 1949 return -1; 1950 1951 if (obj->textrel) { /* Re-protected the text segment. */ 1952 if (mprotect(obj->mapbase, obj->textsize, 1953 PROT_READ|PROT_EXEC) == -1) { 1954 _rtld_error("%s: Cannot write-protect text segment: %s", 1955 obj->path, strerror(errno)); 1956 return -1; 1957 } 1958 } 1959 1960 1961 /* Set the special PLT or GOT entries. */ 1962 init_pltgot(obj); 1963 1964 /* Process the PLT relocations. */ 1965 if (reloc_plt(obj) == -1) 1966 return -1; 1967 /* Relocate the jump slots if we are doing immediate binding. */ 1968 if (obj->bind_now || bind_now) 1969 if (reloc_jmpslots(obj, lockstate) == -1) 1970 return -1; 1971 1972 /* 1973 * Set up the magic number and version in the Obj_Entry. These 1974 * were checked in the crt1.o from the original ElfKit, so we 1975 * set them for backward compatibility. 1976 */ 1977 obj->magic = RTLD_MAGIC; 1978 obj->version = RTLD_VERSION; 1979 } 1980 1981 /* 1982 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 1983 * referencing STT_GNU_IFUNC symbols is postponed till the other 1984 * relocations are done. The indirect functions specified as 1985 * ifunc are allowed to call other symbols, so we need to have 1986 * objects relocated before asking for resolution from indirects. 1987 * 1988 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 1989 * instead of the usual lazy handling of PLT slots. It is 1990 * consistent with how GNU does it. 1991 */ 1992 for (obj = first; obj != NULL; obj = obj->next) { 1993 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 1994 return (-1); 1995 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 1996 reloc_gnu_ifunc(obj, lockstate) == -1) 1997 return (-1); 1998 } 1999 return 0; 2000 } 2001 2002 /* 2003 * Cleanup procedure. It will be called (by the atexit mechanism) just 2004 * before the process exits. 2005 */ 2006 static void 2007 rtld_exit(void) 2008 { 2009 RtldLockState lockstate; 2010 2011 wlock_acquire(rtld_bind_lock, &lockstate); 2012 dbg("rtld_exit()"); 2013 objlist_call_fini(&list_fini, NULL, &lockstate); 2014 /* No need to remove the items from the list, since we are exiting. */ 2015 if (!libmap_disable) 2016 lm_fini(); 2017 lock_release(rtld_bind_lock, &lockstate); 2018 } 2019 2020 static void * 2021 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2022 { 2023 #ifdef COMPAT_32BIT 2024 const char *trans; 2025 #endif 2026 if (path == NULL) 2027 return (NULL); 2028 2029 path += strspn(path, ":;"); 2030 while (*path != '\0') { 2031 size_t len; 2032 char *res; 2033 2034 len = strcspn(path, ":;"); 2035 #ifdef COMPAT_32BIT 2036 trans = lm_findn(NULL, path, len); 2037 if (trans) 2038 res = callback(trans, strlen(trans), arg); 2039 else 2040 #endif 2041 res = callback(path, len, arg); 2042 2043 if (res != NULL) 2044 return (res); 2045 2046 path += len; 2047 path += strspn(path, ":;"); 2048 } 2049 2050 return (NULL); 2051 } 2052 2053 struct try_library_args { 2054 const char *name; 2055 size_t namelen; 2056 char *buffer; 2057 size_t buflen; 2058 }; 2059 2060 static void * 2061 try_library_path(const char *dir, size_t dirlen, void *param) 2062 { 2063 struct try_library_args *arg; 2064 2065 arg = param; 2066 if (*dir == '/' || trust) { 2067 char *pathname; 2068 2069 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2070 return (NULL); 2071 2072 pathname = arg->buffer; 2073 strncpy(pathname, dir, dirlen); 2074 pathname[dirlen] = '/'; 2075 strcpy(pathname + dirlen + 1, arg->name); 2076 2077 dbg(" Trying \"%s\"", pathname); 2078 if (access(pathname, F_OK) == 0) { /* We found it */ 2079 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2080 strcpy(pathname, arg->buffer); 2081 return (pathname); 2082 } 2083 } 2084 return (NULL); 2085 } 2086 2087 static char * 2088 search_library_path(const char *name, const char *path) 2089 { 2090 char *p; 2091 struct try_library_args arg; 2092 2093 if (path == NULL) 2094 return NULL; 2095 2096 arg.name = name; 2097 arg.namelen = strlen(name); 2098 arg.buffer = xmalloc(PATH_MAX); 2099 arg.buflen = PATH_MAX; 2100 2101 p = path_enumerate(path, try_library_path, &arg); 2102 2103 free(arg.buffer); 2104 2105 return (p); 2106 } 2107 2108 int 2109 dlclose(void *handle) 2110 { 2111 Obj_Entry *root; 2112 RtldLockState lockstate; 2113 2114 wlock_acquire(rtld_bind_lock, &lockstate); 2115 root = dlcheck(handle); 2116 if (root == NULL) { 2117 lock_release(rtld_bind_lock, &lockstate); 2118 return -1; 2119 } 2120 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2121 root->path); 2122 2123 /* Unreference the object and its dependencies. */ 2124 root->dl_refcount--; 2125 2126 if (root->refcount == 1) { 2127 /* 2128 * The object will be no longer referenced, so we must unload it. 2129 * First, call the fini functions. 2130 */ 2131 objlist_call_fini(&list_fini, root, &lockstate); 2132 2133 unref_dag(root); 2134 2135 /* Finish cleaning up the newly-unreferenced objects. */ 2136 GDB_STATE(RT_DELETE,&root->linkmap); 2137 unload_object(root); 2138 GDB_STATE(RT_CONSISTENT,NULL); 2139 } else 2140 unref_dag(root); 2141 2142 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2143 lock_release(rtld_bind_lock, &lockstate); 2144 return 0; 2145 } 2146 2147 char * 2148 dlerror(void) 2149 { 2150 char *msg = error_message; 2151 error_message = NULL; 2152 return msg; 2153 } 2154 2155 /* 2156 * This function is deprecated and has no effect. 2157 */ 2158 void 2159 dllockinit(void *context, 2160 void *(*lock_create)(void *context), 2161 void (*rlock_acquire)(void *lock), 2162 void (*wlock_acquire)(void *lock), 2163 void (*lock_release)(void *lock), 2164 void (*lock_destroy)(void *lock), 2165 void (*context_destroy)(void *context)) 2166 { 2167 static void *cur_context; 2168 static void (*cur_context_destroy)(void *); 2169 2170 /* Just destroy the context from the previous call, if necessary. */ 2171 if (cur_context_destroy != NULL) 2172 cur_context_destroy(cur_context); 2173 cur_context = context; 2174 cur_context_destroy = context_destroy; 2175 } 2176 2177 void * 2178 dlopen(const char *name, int mode) 2179 { 2180 RtldLockState lockstate; 2181 int lo_flags; 2182 2183 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2184 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2185 if (ld_tracing != NULL) { 2186 rlock_acquire(rtld_bind_lock, &lockstate); 2187 if (sigsetjmp(lockstate.env, 0) != 0) 2188 lock_upgrade(rtld_bind_lock, &lockstate); 2189 environ = (char **)*get_program_var_addr("environ", &lockstate); 2190 lock_release(rtld_bind_lock, &lockstate); 2191 } 2192 lo_flags = RTLD_LO_DLOPEN; 2193 if (mode & RTLD_NODELETE) 2194 lo_flags |= RTLD_LO_NODELETE; 2195 if (mode & RTLD_NOLOAD) 2196 lo_flags |= RTLD_LO_NOLOAD; 2197 if (ld_tracing != NULL) 2198 lo_flags |= RTLD_LO_TRACE; 2199 2200 return (dlopen_object(name, obj_main, lo_flags, 2201 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2202 } 2203 2204 static Obj_Entry * 2205 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode) 2206 { 2207 Obj_Entry **old_obj_tail; 2208 Obj_Entry *obj; 2209 Objlist initlist; 2210 RtldLockState lockstate; 2211 int result; 2212 2213 objlist_init(&initlist); 2214 2215 wlock_acquire(rtld_bind_lock, &lockstate); 2216 GDB_STATE(RT_ADD,NULL); 2217 2218 old_obj_tail = obj_tail; 2219 obj = NULL; 2220 if (name == NULL) { 2221 obj = obj_main; 2222 obj->refcount++; 2223 } else { 2224 obj = load_object(name, refobj, lo_flags); 2225 } 2226 2227 if (obj) { 2228 obj->dl_refcount++; 2229 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2230 objlist_push_tail(&list_global, obj); 2231 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2232 assert(*old_obj_tail == obj); 2233 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN); 2234 init_dag(obj); 2235 ref_dag(obj); 2236 if (result != -1) 2237 result = rtld_verify_versions(&obj->dagmembers); 2238 if (result != -1 && ld_tracing) 2239 goto trace; 2240 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK) 2241 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) { 2242 obj->dl_refcount--; 2243 unref_dag(obj); 2244 if (obj->refcount == 0) 2245 unload_object(obj); 2246 obj = NULL; 2247 } else { 2248 /* Make list of init functions to call. */ 2249 initlist_add_objects(obj, &obj->next, &initlist); 2250 } 2251 } else { 2252 2253 /* 2254 * Bump the reference counts for objects on this DAG. If 2255 * this is the first dlopen() call for the object that was 2256 * already loaded as a dependency, initialize the dag 2257 * starting at it. 2258 */ 2259 init_dag(obj); 2260 ref_dag(obj); 2261 2262 if ((lo_flags & RTLD_LO_TRACE) != 0) 2263 goto trace; 2264 } 2265 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2266 obj->z_nodelete) && !obj->ref_nodel) { 2267 dbg("obj %s nodelete", obj->path); 2268 ref_dag(obj); 2269 obj->z_nodelete = obj->ref_nodel = true; 2270 } 2271 } 2272 2273 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2274 name); 2275 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2276 2277 map_stacks_exec(&lockstate); 2278 2279 /* Call the init functions. */ 2280 objlist_call_init(&initlist, &lockstate); 2281 objlist_clear(&initlist); 2282 lock_release(rtld_bind_lock, &lockstate); 2283 return obj; 2284 trace: 2285 trace_loaded_objects(obj); 2286 lock_release(rtld_bind_lock, &lockstate); 2287 exit(0); 2288 } 2289 2290 static void * 2291 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2292 int flags) 2293 { 2294 DoneList donelist; 2295 const Obj_Entry *obj, *defobj; 2296 const Elf_Sym *def; 2297 SymLook req; 2298 RtldLockState lockstate; 2299 int res; 2300 2301 def = NULL; 2302 defobj = NULL; 2303 symlook_init(&req, name); 2304 req.ventry = ve; 2305 req.flags = flags | SYMLOOK_IN_PLT; 2306 req.lockstate = &lockstate; 2307 2308 rlock_acquire(rtld_bind_lock, &lockstate); 2309 if (sigsetjmp(lockstate.env, 0) != 0) 2310 lock_upgrade(rtld_bind_lock, &lockstate); 2311 if (handle == NULL || handle == RTLD_NEXT || 2312 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2313 2314 if ((obj = obj_from_addr(retaddr)) == NULL) { 2315 _rtld_error("Cannot determine caller's shared object"); 2316 lock_release(rtld_bind_lock, &lockstate); 2317 return NULL; 2318 } 2319 if (handle == NULL) { /* Just the caller's shared object. */ 2320 res = symlook_obj(&req, obj); 2321 if (res == 0) { 2322 def = req.sym_out; 2323 defobj = req.defobj_out; 2324 } 2325 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2326 handle == RTLD_SELF) { /* ... caller included */ 2327 if (handle == RTLD_NEXT) 2328 obj = obj->next; 2329 for (; obj != NULL; obj = obj->next) { 2330 res = symlook_obj(&req, obj); 2331 if (res == 0) { 2332 if (def == NULL || 2333 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2334 def = req.sym_out; 2335 defobj = req.defobj_out; 2336 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2337 break; 2338 } 2339 } 2340 } 2341 /* 2342 * Search the dynamic linker itself, and possibly resolve the 2343 * symbol from there. This is how the application links to 2344 * dynamic linker services such as dlopen. 2345 */ 2346 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2347 res = symlook_obj(&req, &obj_rtld); 2348 if (res == 0) { 2349 def = req.sym_out; 2350 defobj = req.defobj_out; 2351 } 2352 } 2353 } else { 2354 assert(handle == RTLD_DEFAULT); 2355 res = symlook_default(&req, obj); 2356 if (res == 0) { 2357 defobj = req.defobj_out; 2358 def = req.sym_out; 2359 } 2360 } 2361 } else { 2362 if ((obj = dlcheck(handle)) == NULL) { 2363 lock_release(rtld_bind_lock, &lockstate); 2364 return NULL; 2365 } 2366 2367 donelist_init(&donelist); 2368 if (obj->mainprog) { 2369 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2370 res = symlook_global(&req, &donelist); 2371 if (res == 0) { 2372 def = req.sym_out; 2373 defobj = req.defobj_out; 2374 } 2375 /* 2376 * Search the dynamic linker itself, and possibly resolve the 2377 * symbol from there. This is how the application links to 2378 * dynamic linker services such as dlopen. 2379 */ 2380 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2381 res = symlook_obj(&req, &obj_rtld); 2382 if (res == 0) { 2383 def = req.sym_out; 2384 defobj = req.defobj_out; 2385 } 2386 } 2387 } 2388 else { 2389 /* Search the whole DAG rooted at the given object. */ 2390 res = symlook_list(&req, &obj->dagmembers, &donelist); 2391 if (res == 0) { 2392 def = req.sym_out; 2393 defobj = req.defobj_out; 2394 } 2395 } 2396 } 2397 2398 if (def != NULL) { 2399 lock_release(rtld_bind_lock, &lockstate); 2400 2401 /* 2402 * The value required by the caller is derived from the value 2403 * of the symbol. For the ia64 architecture, we need to 2404 * construct a function descriptor which the caller can use to 2405 * call the function with the right 'gp' value. For other 2406 * architectures and for non-functions, the value is simply 2407 * the relocated value of the symbol. 2408 */ 2409 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2410 return (make_function_pointer(def, defobj)); 2411 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 2412 return (rtld_resolve_ifunc(defobj, def)); 2413 else 2414 return (defobj->relocbase + def->st_value); 2415 } 2416 2417 _rtld_error("Undefined symbol \"%s\"", name); 2418 lock_release(rtld_bind_lock, &lockstate); 2419 return NULL; 2420 } 2421 2422 void * 2423 dlsym(void *handle, const char *name) 2424 { 2425 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2426 SYMLOOK_DLSYM); 2427 } 2428 2429 dlfunc_t 2430 dlfunc(void *handle, const char *name) 2431 { 2432 union { 2433 void *d; 2434 dlfunc_t f; 2435 } rv; 2436 2437 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2438 SYMLOOK_DLSYM); 2439 return (rv.f); 2440 } 2441 2442 void * 2443 dlvsym(void *handle, const char *name, const char *version) 2444 { 2445 Ver_Entry ventry; 2446 2447 ventry.name = version; 2448 ventry.file = NULL; 2449 ventry.hash = elf_hash(version); 2450 ventry.flags= 0; 2451 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2452 SYMLOOK_DLSYM); 2453 } 2454 2455 int 2456 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2457 { 2458 const Obj_Entry *obj; 2459 RtldLockState lockstate; 2460 2461 rlock_acquire(rtld_bind_lock, &lockstate); 2462 obj = obj_from_addr(addr); 2463 if (obj == NULL) { 2464 _rtld_error("No shared object contains address"); 2465 lock_release(rtld_bind_lock, &lockstate); 2466 return (0); 2467 } 2468 rtld_fill_dl_phdr_info(obj, phdr_info); 2469 lock_release(rtld_bind_lock, &lockstate); 2470 return (1); 2471 } 2472 2473 int 2474 dladdr(const void *addr, Dl_info *info) 2475 { 2476 const Obj_Entry *obj; 2477 const Elf_Sym *def; 2478 void *symbol_addr; 2479 unsigned long symoffset; 2480 RtldLockState lockstate; 2481 2482 rlock_acquire(rtld_bind_lock, &lockstate); 2483 obj = obj_from_addr(addr); 2484 if (obj == NULL) { 2485 _rtld_error("No shared object contains address"); 2486 lock_release(rtld_bind_lock, &lockstate); 2487 return 0; 2488 } 2489 info->dli_fname = obj->path; 2490 info->dli_fbase = obj->mapbase; 2491 info->dli_saddr = (void *)0; 2492 info->dli_sname = NULL; 2493 2494 /* 2495 * Walk the symbol list looking for the symbol whose address is 2496 * closest to the address sent in. 2497 */ 2498 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2499 def = obj->symtab + symoffset; 2500 2501 /* 2502 * For skip the symbol if st_shndx is either SHN_UNDEF or 2503 * SHN_COMMON. 2504 */ 2505 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2506 continue; 2507 2508 /* 2509 * If the symbol is greater than the specified address, or if it 2510 * is further away from addr than the current nearest symbol, 2511 * then reject it. 2512 */ 2513 symbol_addr = obj->relocbase + def->st_value; 2514 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2515 continue; 2516 2517 /* Update our idea of the nearest symbol. */ 2518 info->dli_sname = obj->strtab + def->st_name; 2519 info->dli_saddr = symbol_addr; 2520 2521 /* Exact match? */ 2522 if (info->dli_saddr == addr) 2523 break; 2524 } 2525 lock_release(rtld_bind_lock, &lockstate); 2526 return 1; 2527 } 2528 2529 int 2530 dlinfo(void *handle, int request, void *p) 2531 { 2532 const Obj_Entry *obj; 2533 RtldLockState lockstate; 2534 int error; 2535 2536 rlock_acquire(rtld_bind_lock, &lockstate); 2537 2538 if (handle == NULL || handle == RTLD_SELF) { 2539 void *retaddr; 2540 2541 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2542 if ((obj = obj_from_addr(retaddr)) == NULL) 2543 _rtld_error("Cannot determine caller's shared object"); 2544 } else 2545 obj = dlcheck(handle); 2546 2547 if (obj == NULL) { 2548 lock_release(rtld_bind_lock, &lockstate); 2549 return (-1); 2550 } 2551 2552 error = 0; 2553 switch (request) { 2554 case RTLD_DI_LINKMAP: 2555 *((struct link_map const **)p) = &obj->linkmap; 2556 break; 2557 case RTLD_DI_ORIGIN: 2558 error = rtld_dirname(obj->path, p); 2559 break; 2560 2561 case RTLD_DI_SERINFOSIZE: 2562 case RTLD_DI_SERINFO: 2563 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2564 break; 2565 2566 default: 2567 _rtld_error("Invalid request %d passed to dlinfo()", request); 2568 error = -1; 2569 } 2570 2571 lock_release(rtld_bind_lock, &lockstate); 2572 2573 return (error); 2574 } 2575 2576 static void 2577 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2578 { 2579 2580 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2581 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2582 STAILQ_FIRST(&obj->names)->name : obj->path; 2583 phdr_info->dlpi_phdr = obj->phdr; 2584 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2585 phdr_info->dlpi_tls_modid = obj->tlsindex; 2586 phdr_info->dlpi_tls_data = obj->tlsinit; 2587 phdr_info->dlpi_adds = obj_loads; 2588 phdr_info->dlpi_subs = obj_loads - obj_count; 2589 } 2590 2591 int 2592 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2593 { 2594 struct dl_phdr_info phdr_info; 2595 const Obj_Entry *obj; 2596 RtldLockState bind_lockstate, phdr_lockstate; 2597 int error; 2598 2599 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2600 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2601 2602 error = 0; 2603 2604 for (obj = obj_list; obj != NULL; obj = obj->next) { 2605 rtld_fill_dl_phdr_info(obj, &phdr_info); 2606 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2607 break; 2608 2609 } 2610 lock_release(rtld_bind_lock, &bind_lockstate); 2611 lock_release(rtld_phdr_lock, &phdr_lockstate); 2612 2613 return (error); 2614 } 2615 2616 struct fill_search_info_args { 2617 int request; 2618 unsigned int flags; 2619 Dl_serinfo *serinfo; 2620 Dl_serpath *serpath; 2621 char *strspace; 2622 }; 2623 2624 static void * 2625 fill_search_info(const char *dir, size_t dirlen, void *param) 2626 { 2627 struct fill_search_info_args *arg; 2628 2629 arg = param; 2630 2631 if (arg->request == RTLD_DI_SERINFOSIZE) { 2632 arg->serinfo->dls_cnt ++; 2633 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2634 } else { 2635 struct dl_serpath *s_entry; 2636 2637 s_entry = arg->serpath; 2638 s_entry->dls_name = arg->strspace; 2639 s_entry->dls_flags = arg->flags; 2640 2641 strncpy(arg->strspace, dir, dirlen); 2642 arg->strspace[dirlen] = '\0'; 2643 2644 arg->strspace += dirlen + 1; 2645 arg->serpath++; 2646 } 2647 2648 return (NULL); 2649 } 2650 2651 static int 2652 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2653 { 2654 struct dl_serinfo _info; 2655 struct fill_search_info_args args; 2656 2657 args.request = RTLD_DI_SERINFOSIZE; 2658 args.serinfo = &_info; 2659 2660 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2661 _info.dls_cnt = 0; 2662 2663 path_enumerate(ld_library_path, fill_search_info, &args); 2664 path_enumerate(obj->rpath, fill_search_info, &args); 2665 path_enumerate(gethints(), fill_search_info, &args); 2666 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 2667 2668 2669 if (request == RTLD_DI_SERINFOSIZE) { 2670 info->dls_size = _info.dls_size; 2671 info->dls_cnt = _info.dls_cnt; 2672 return (0); 2673 } 2674 2675 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 2676 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 2677 return (-1); 2678 } 2679 2680 args.request = RTLD_DI_SERINFO; 2681 args.serinfo = info; 2682 args.serpath = &info->dls_serpath[0]; 2683 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 2684 2685 args.flags = LA_SER_LIBPATH; 2686 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 2687 return (-1); 2688 2689 args.flags = LA_SER_RUNPATH; 2690 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 2691 return (-1); 2692 2693 args.flags = LA_SER_CONFIG; 2694 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 2695 return (-1); 2696 2697 args.flags = LA_SER_DEFAULT; 2698 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 2699 return (-1); 2700 return (0); 2701 } 2702 2703 static int 2704 rtld_dirname(const char *path, char *bname) 2705 { 2706 const char *endp; 2707 2708 /* Empty or NULL string gets treated as "." */ 2709 if (path == NULL || *path == '\0') { 2710 bname[0] = '.'; 2711 bname[1] = '\0'; 2712 return (0); 2713 } 2714 2715 /* Strip trailing slashes */ 2716 endp = path + strlen(path) - 1; 2717 while (endp > path && *endp == '/') 2718 endp--; 2719 2720 /* Find the start of the dir */ 2721 while (endp > path && *endp != '/') 2722 endp--; 2723 2724 /* Either the dir is "/" or there are no slashes */ 2725 if (endp == path) { 2726 bname[0] = *endp == '/' ? '/' : '.'; 2727 bname[1] = '\0'; 2728 return (0); 2729 } else { 2730 do { 2731 endp--; 2732 } while (endp > path && *endp == '/'); 2733 } 2734 2735 if (endp - path + 2 > PATH_MAX) 2736 { 2737 _rtld_error("Filename is too long: %s", path); 2738 return(-1); 2739 } 2740 2741 strncpy(bname, path, endp - path + 1); 2742 bname[endp - path + 1] = '\0'; 2743 return (0); 2744 } 2745 2746 static int 2747 rtld_dirname_abs(const char *path, char *base) 2748 { 2749 char base_rel[PATH_MAX]; 2750 2751 if (rtld_dirname(path, base) == -1) 2752 return (-1); 2753 if (base[0] == '/') 2754 return (0); 2755 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 2756 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 2757 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 2758 return (-1); 2759 strcpy(base, base_rel); 2760 return (0); 2761 } 2762 2763 static void 2764 linkmap_add(Obj_Entry *obj) 2765 { 2766 struct link_map *l = &obj->linkmap; 2767 struct link_map *prev; 2768 2769 obj->linkmap.l_name = obj->path; 2770 obj->linkmap.l_addr = obj->mapbase; 2771 obj->linkmap.l_ld = obj->dynamic; 2772 #ifdef __mips__ 2773 /* GDB needs load offset on MIPS to use the symbols */ 2774 obj->linkmap.l_offs = obj->relocbase; 2775 #endif 2776 2777 if (r_debug.r_map == NULL) { 2778 r_debug.r_map = l; 2779 return; 2780 } 2781 2782 /* 2783 * Scan to the end of the list, but not past the entry for the 2784 * dynamic linker, which we want to keep at the very end. 2785 */ 2786 for (prev = r_debug.r_map; 2787 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 2788 prev = prev->l_next) 2789 ; 2790 2791 /* Link in the new entry. */ 2792 l->l_prev = prev; 2793 l->l_next = prev->l_next; 2794 if (l->l_next != NULL) 2795 l->l_next->l_prev = l; 2796 prev->l_next = l; 2797 } 2798 2799 static void 2800 linkmap_delete(Obj_Entry *obj) 2801 { 2802 struct link_map *l = &obj->linkmap; 2803 2804 if (l->l_prev == NULL) { 2805 if ((r_debug.r_map = l->l_next) != NULL) 2806 l->l_next->l_prev = NULL; 2807 return; 2808 } 2809 2810 if ((l->l_prev->l_next = l->l_next) != NULL) 2811 l->l_next->l_prev = l->l_prev; 2812 } 2813 2814 /* 2815 * Function for the debugger to set a breakpoint on to gain control. 2816 * 2817 * The two parameters allow the debugger to easily find and determine 2818 * what the runtime loader is doing and to whom it is doing it. 2819 * 2820 * When the loadhook trap is hit (r_debug_state, set at program 2821 * initialization), the arguments can be found on the stack: 2822 * 2823 * +8 struct link_map *m 2824 * +4 struct r_debug *rd 2825 * +0 RetAddr 2826 */ 2827 void 2828 r_debug_state(struct r_debug* rd, struct link_map *m) 2829 { 2830 /* 2831 * The following is a hack to force the compiler to emit calls to 2832 * this function, even when optimizing. If the function is empty, 2833 * the compiler is not obliged to emit any code for calls to it, 2834 * even when marked __noinline. However, gdb depends on those 2835 * calls being made. 2836 */ 2837 __asm __volatile("" : : : "memory"); 2838 } 2839 2840 /* 2841 * Get address of the pointer variable in the main program. 2842 * Prefer non-weak symbol over the weak one. 2843 */ 2844 static const void ** 2845 get_program_var_addr(const char *name, RtldLockState *lockstate) 2846 { 2847 SymLook req; 2848 DoneList donelist; 2849 2850 symlook_init(&req, name); 2851 req.lockstate = lockstate; 2852 donelist_init(&donelist); 2853 if (symlook_global(&req, &donelist) != 0) 2854 return (NULL); 2855 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 2856 return ((const void **)make_function_pointer(req.sym_out, 2857 req.defobj_out)); 2858 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 2859 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 2860 else 2861 return ((const void **)(req.defobj_out->relocbase + 2862 req.sym_out->st_value)); 2863 } 2864 2865 /* 2866 * Set a pointer variable in the main program to the given value. This 2867 * is used to set key variables such as "environ" before any of the 2868 * init functions are called. 2869 */ 2870 static void 2871 set_program_var(const char *name, const void *value) 2872 { 2873 const void **addr; 2874 2875 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 2876 dbg("\"%s\": *%p <-- %p", name, addr, value); 2877 *addr = value; 2878 } 2879 } 2880 2881 /* 2882 * Search the global objects, including dependencies and main object, 2883 * for the given symbol. 2884 */ 2885 static int 2886 symlook_global(SymLook *req, DoneList *donelist) 2887 { 2888 SymLook req1; 2889 const Objlist_Entry *elm; 2890 int res; 2891 2892 symlook_init_from_req(&req1, req); 2893 2894 /* Search all objects loaded at program start up. */ 2895 if (req->defobj_out == NULL || 2896 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2897 res = symlook_list(&req1, &list_main, donelist); 2898 if (res == 0 && (req->defobj_out == NULL || 2899 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2900 req->sym_out = req1.sym_out; 2901 req->defobj_out = req1.defobj_out; 2902 assert(req->defobj_out != NULL); 2903 } 2904 } 2905 2906 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 2907 STAILQ_FOREACH(elm, &list_global, link) { 2908 if (req->defobj_out != NULL && 2909 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2910 break; 2911 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 2912 if (res == 0 && (req->defobj_out == NULL || 2913 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2914 req->sym_out = req1.sym_out; 2915 req->defobj_out = req1.defobj_out; 2916 assert(req->defobj_out != NULL); 2917 } 2918 } 2919 2920 return (req->sym_out != NULL ? 0 : ESRCH); 2921 } 2922 2923 /* 2924 * Given a symbol name in a referencing object, find the corresponding 2925 * definition of the symbol. Returns a pointer to the symbol, or NULL if 2926 * no definition was found. Returns a pointer to the Obj_Entry of the 2927 * defining object via the reference parameter DEFOBJ_OUT. 2928 */ 2929 static int 2930 symlook_default(SymLook *req, const Obj_Entry *refobj) 2931 { 2932 DoneList donelist; 2933 const Objlist_Entry *elm; 2934 SymLook req1; 2935 int res; 2936 2937 donelist_init(&donelist); 2938 symlook_init_from_req(&req1, req); 2939 2940 /* Look first in the referencing object if linked symbolically. */ 2941 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 2942 res = symlook_obj(&req1, refobj); 2943 if (res == 0) { 2944 req->sym_out = req1.sym_out; 2945 req->defobj_out = req1.defobj_out; 2946 assert(req->defobj_out != NULL); 2947 } 2948 } 2949 2950 symlook_global(req, &donelist); 2951 2952 /* Search all dlopened DAGs containing the referencing object. */ 2953 STAILQ_FOREACH(elm, &refobj->dldags, link) { 2954 if (req->sym_out != NULL && 2955 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 2956 break; 2957 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 2958 if (res == 0 && (req->sym_out == NULL || 2959 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 2960 req->sym_out = req1.sym_out; 2961 req->defobj_out = req1.defobj_out; 2962 assert(req->defobj_out != NULL); 2963 } 2964 } 2965 2966 /* 2967 * Search the dynamic linker itself, and possibly resolve the 2968 * symbol from there. This is how the application links to 2969 * dynamic linker services such as dlopen. 2970 */ 2971 if (req->sym_out == NULL || 2972 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 2973 res = symlook_obj(&req1, &obj_rtld); 2974 if (res == 0) { 2975 req->sym_out = req1.sym_out; 2976 req->defobj_out = req1.defobj_out; 2977 assert(req->defobj_out != NULL); 2978 } 2979 } 2980 2981 return (req->sym_out != NULL ? 0 : ESRCH); 2982 } 2983 2984 static int 2985 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 2986 { 2987 const Elf_Sym *def; 2988 const Obj_Entry *defobj; 2989 const Objlist_Entry *elm; 2990 SymLook req1; 2991 int res; 2992 2993 def = NULL; 2994 defobj = NULL; 2995 STAILQ_FOREACH(elm, objlist, link) { 2996 if (donelist_check(dlp, elm->obj)) 2997 continue; 2998 symlook_init_from_req(&req1, req); 2999 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3000 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3001 def = req1.sym_out; 3002 defobj = req1.defobj_out; 3003 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3004 break; 3005 } 3006 } 3007 } 3008 if (def != NULL) { 3009 req->sym_out = def; 3010 req->defobj_out = defobj; 3011 return (0); 3012 } 3013 return (ESRCH); 3014 } 3015 3016 /* 3017 * Search the chain of DAGS cointed to by the given Needed_Entry 3018 * for a symbol of the given name. Each DAG is scanned completely 3019 * before advancing to the next one. Returns a pointer to the symbol, 3020 * or NULL if no definition was found. 3021 */ 3022 static int 3023 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3024 { 3025 const Elf_Sym *def; 3026 const Needed_Entry *n; 3027 const Obj_Entry *defobj; 3028 SymLook req1; 3029 int res; 3030 3031 def = NULL; 3032 defobj = NULL; 3033 symlook_init_from_req(&req1, req); 3034 for (n = needed; n != NULL; n = n->next) { 3035 if (n->obj == NULL || 3036 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3037 continue; 3038 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3039 def = req1.sym_out; 3040 defobj = req1.defobj_out; 3041 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3042 break; 3043 } 3044 } 3045 if (def != NULL) { 3046 req->sym_out = def; 3047 req->defobj_out = defobj; 3048 return (0); 3049 } 3050 return (ESRCH); 3051 } 3052 3053 /* 3054 * Search the symbol table of a single shared object for a symbol of 3055 * the given name and version, if requested. Returns a pointer to the 3056 * symbol, or NULL if no definition was found. If the object is 3057 * filter, return filtered symbol from filtee. 3058 * 3059 * The symbol's hash value is passed in for efficiency reasons; that 3060 * eliminates many recomputations of the hash value. 3061 */ 3062 int 3063 symlook_obj(SymLook *req, const Obj_Entry *obj) 3064 { 3065 DoneList donelist; 3066 SymLook req1; 3067 int res, mres; 3068 3069 mres = symlook_obj1(req, obj); 3070 if (mres == 0) { 3071 if (obj->needed_filtees != NULL) { 3072 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3073 donelist_init(&donelist); 3074 symlook_init_from_req(&req1, req); 3075 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3076 if (res == 0) { 3077 req->sym_out = req1.sym_out; 3078 req->defobj_out = req1.defobj_out; 3079 } 3080 return (res); 3081 } 3082 if (obj->needed_aux_filtees != NULL) { 3083 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate); 3084 donelist_init(&donelist); 3085 symlook_init_from_req(&req1, req); 3086 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3087 if (res == 0) { 3088 req->sym_out = req1.sym_out; 3089 req->defobj_out = req1.defobj_out; 3090 return (res); 3091 } 3092 } 3093 } 3094 return (mres); 3095 } 3096 3097 static int 3098 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3099 { 3100 unsigned long symnum; 3101 const Elf_Sym *vsymp; 3102 Elf_Versym verndx; 3103 int vcount; 3104 3105 if (obj->buckets == NULL) 3106 return (ESRCH); 3107 3108 vsymp = NULL; 3109 vcount = 0; 3110 symnum = obj->buckets[req->hash % obj->nbuckets]; 3111 3112 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3113 const Elf_Sym *symp; 3114 const char *strp; 3115 3116 if (symnum >= obj->nchains) 3117 return (ESRCH); /* Bad object */ 3118 3119 symp = obj->symtab + symnum; 3120 strp = obj->strtab + symp->st_name; 3121 3122 switch (ELF_ST_TYPE(symp->st_info)) { 3123 case STT_FUNC: 3124 case STT_NOTYPE: 3125 case STT_OBJECT: 3126 case STT_GNU_IFUNC: 3127 if (symp->st_value == 0) 3128 continue; 3129 /* fallthrough */ 3130 case STT_TLS: 3131 if (symp->st_shndx != SHN_UNDEF) 3132 break; 3133 #ifndef __mips__ 3134 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3135 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3136 break; 3137 /* fallthrough */ 3138 #endif 3139 default: 3140 continue; 3141 } 3142 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3143 continue; 3144 3145 if (req->ventry == NULL) { 3146 if (obj->versyms != NULL) { 3147 verndx = VER_NDX(obj->versyms[symnum]); 3148 if (verndx > obj->vernum) { 3149 _rtld_error("%s: symbol %s references wrong version %d", 3150 obj->path, obj->strtab + symnum, verndx); 3151 continue; 3152 } 3153 /* 3154 * If we are not called from dlsym (i.e. this is a normal 3155 * relocation from unversioned binary), accept the symbol 3156 * immediately if it happens to have first version after 3157 * this shared object became versioned. Otherwise, if 3158 * symbol is versioned and not hidden, remember it. If it 3159 * is the only symbol with this name exported by the 3160 * shared object, it will be returned as a match at the 3161 * end of the function. If symbol is global (verndx < 2) 3162 * accept it unconditionally. 3163 */ 3164 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3165 verndx == VER_NDX_GIVEN) { 3166 req->sym_out = symp; 3167 req->defobj_out = obj; 3168 return (0); 3169 } 3170 else if (verndx >= VER_NDX_GIVEN) { 3171 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3172 if (vsymp == NULL) 3173 vsymp = symp; 3174 vcount ++; 3175 } 3176 continue; 3177 } 3178 } 3179 req->sym_out = symp; 3180 req->defobj_out = obj; 3181 return (0); 3182 } else { 3183 if (obj->versyms == NULL) { 3184 if (object_match_name(obj, req->ventry->name)) { 3185 _rtld_error("%s: object %s should provide version %s for " 3186 "symbol %s", obj_rtld.path, obj->path, 3187 req->ventry->name, obj->strtab + symnum); 3188 continue; 3189 } 3190 } else { 3191 verndx = VER_NDX(obj->versyms[symnum]); 3192 if (verndx > obj->vernum) { 3193 _rtld_error("%s: symbol %s references wrong version %d", 3194 obj->path, obj->strtab + symnum, verndx); 3195 continue; 3196 } 3197 if (obj->vertab[verndx].hash != req->ventry->hash || 3198 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3199 /* 3200 * Version does not match. Look if this is a global symbol 3201 * and if it is not hidden. If global symbol (verndx < 2) 3202 * is available, use it. Do not return symbol if we are 3203 * called by dlvsym, because dlvsym looks for a specific 3204 * version and default one is not what dlvsym wants. 3205 */ 3206 if ((req->flags & SYMLOOK_DLSYM) || 3207 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3208 (verndx >= VER_NDX_GIVEN)) 3209 continue; 3210 } 3211 } 3212 req->sym_out = symp; 3213 req->defobj_out = obj; 3214 return (0); 3215 } 3216 } 3217 if (vcount == 1) { 3218 req->sym_out = vsymp; 3219 req->defobj_out = obj; 3220 return (0); 3221 } 3222 return (ESRCH); 3223 } 3224 3225 static void 3226 trace_loaded_objects(Obj_Entry *obj) 3227 { 3228 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3229 int c; 3230 3231 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3232 main_local = ""; 3233 3234 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3235 fmt1 = "\t%o => %p (%x)\n"; 3236 3237 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3238 fmt2 = "\t%o (%x)\n"; 3239 3240 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3241 3242 for (; obj; obj = obj->next) { 3243 Needed_Entry *needed; 3244 char *name, *path; 3245 bool is_lib; 3246 3247 if (list_containers && obj->needed != NULL) 3248 rtld_printf("%s:\n", obj->path); 3249 for (needed = obj->needed; needed; needed = needed->next) { 3250 if (needed->obj != NULL) { 3251 if (needed->obj->traced && !list_containers) 3252 continue; 3253 needed->obj->traced = true; 3254 path = needed->obj->path; 3255 } else 3256 path = "not found"; 3257 3258 name = (char *)obj->strtab + needed->name; 3259 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3260 3261 fmt = is_lib ? fmt1 : fmt2; 3262 while ((c = *fmt++) != '\0') { 3263 switch (c) { 3264 default: 3265 rtld_putchar(c); 3266 continue; 3267 case '\\': 3268 switch (c = *fmt) { 3269 case '\0': 3270 continue; 3271 case 'n': 3272 rtld_putchar('\n'); 3273 break; 3274 case 't': 3275 rtld_putchar('\t'); 3276 break; 3277 } 3278 break; 3279 case '%': 3280 switch (c = *fmt) { 3281 case '\0': 3282 continue; 3283 case '%': 3284 default: 3285 rtld_putchar(c); 3286 break; 3287 case 'A': 3288 rtld_putstr(main_local); 3289 break; 3290 case 'a': 3291 rtld_putstr(obj_main->path); 3292 break; 3293 case 'o': 3294 rtld_putstr(name); 3295 break; 3296 #if 0 3297 case 'm': 3298 rtld_printf("%d", sodp->sod_major); 3299 break; 3300 case 'n': 3301 rtld_printf("%d", sodp->sod_minor); 3302 break; 3303 #endif 3304 case 'p': 3305 rtld_putstr(path); 3306 break; 3307 case 'x': 3308 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 3309 0); 3310 break; 3311 } 3312 break; 3313 } 3314 ++fmt; 3315 } 3316 } 3317 } 3318 } 3319 3320 /* 3321 * Unload a dlopened object and its dependencies from memory and from 3322 * our data structures. It is assumed that the DAG rooted in the 3323 * object has already been unreferenced, and that the object has a 3324 * reference count of 0. 3325 */ 3326 static void 3327 unload_object(Obj_Entry *root) 3328 { 3329 Obj_Entry *obj; 3330 Obj_Entry **linkp; 3331 3332 assert(root->refcount == 0); 3333 3334 /* 3335 * Pass over the DAG removing unreferenced objects from 3336 * appropriate lists. 3337 */ 3338 unlink_object(root); 3339 3340 /* Unmap all objects that are no longer referenced. */ 3341 linkp = &obj_list->next; 3342 while ((obj = *linkp) != NULL) { 3343 if (obj->refcount == 0) { 3344 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3345 obj->path); 3346 dbg("unloading \"%s\"", obj->path); 3347 unload_filtees(root); 3348 munmap(obj->mapbase, obj->mapsize); 3349 linkmap_delete(obj); 3350 *linkp = obj->next; 3351 obj_count--; 3352 obj_free(obj); 3353 } else 3354 linkp = &obj->next; 3355 } 3356 obj_tail = linkp; 3357 } 3358 3359 static void 3360 unlink_object(Obj_Entry *root) 3361 { 3362 Objlist_Entry *elm; 3363 3364 if (root->refcount == 0) { 3365 /* Remove the object from the RTLD_GLOBAL list. */ 3366 objlist_remove(&list_global, root); 3367 3368 /* Remove the object from all objects' DAG lists. */ 3369 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3370 objlist_remove(&elm->obj->dldags, root); 3371 if (elm->obj != root) 3372 unlink_object(elm->obj); 3373 } 3374 } 3375 } 3376 3377 static void 3378 ref_dag(Obj_Entry *root) 3379 { 3380 Objlist_Entry *elm; 3381 3382 assert(root->dag_inited); 3383 STAILQ_FOREACH(elm, &root->dagmembers, link) 3384 elm->obj->refcount++; 3385 } 3386 3387 static void 3388 unref_dag(Obj_Entry *root) 3389 { 3390 Objlist_Entry *elm; 3391 3392 assert(root->dag_inited); 3393 STAILQ_FOREACH(elm, &root->dagmembers, link) 3394 elm->obj->refcount--; 3395 } 3396 3397 /* 3398 * Common code for MD __tls_get_addr(). 3399 */ 3400 void * 3401 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 3402 { 3403 Elf_Addr* dtv = *dtvp; 3404 RtldLockState lockstate; 3405 3406 /* Check dtv generation in case new modules have arrived */ 3407 if (dtv[0] != tls_dtv_generation) { 3408 Elf_Addr* newdtv; 3409 int to_copy; 3410 3411 wlock_acquire(rtld_bind_lock, &lockstate); 3412 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3413 to_copy = dtv[1]; 3414 if (to_copy > tls_max_index) 3415 to_copy = tls_max_index; 3416 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3417 newdtv[0] = tls_dtv_generation; 3418 newdtv[1] = tls_max_index; 3419 free(dtv); 3420 lock_release(rtld_bind_lock, &lockstate); 3421 dtv = *dtvp = newdtv; 3422 } 3423 3424 /* Dynamically allocate module TLS if necessary */ 3425 if (!dtv[index + 1]) { 3426 /* Signal safe, wlock will block out signals. */ 3427 wlock_acquire(rtld_bind_lock, &lockstate); 3428 if (!dtv[index + 1]) 3429 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3430 lock_release(rtld_bind_lock, &lockstate); 3431 } 3432 return (void*) (dtv[index + 1] + offset); 3433 } 3434 3435 /* XXX not sure what variants to use for arm. */ 3436 3437 #if defined(__ia64__) || defined(__powerpc__) 3438 3439 /* 3440 * Allocate Static TLS using the Variant I method. 3441 */ 3442 void * 3443 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3444 { 3445 Obj_Entry *obj; 3446 char *tcb; 3447 Elf_Addr **tls; 3448 Elf_Addr *dtv; 3449 Elf_Addr addr; 3450 int i; 3451 3452 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3453 return (oldtcb); 3454 3455 assert(tcbsize >= TLS_TCB_SIZE); 3456 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3457 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3458 3459 if (oldtcb != NULL) { 3460 memcpy(tls, oldtcb, tls_static_space); 3461 free(oldtcb); 3462 3463 /* Adjust the DTV. */ 3464 dtv = tls[0]; 3465 for (i = 0; i < dtv[1]; i++) { 3466 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3467 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3468 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3469 } 3470 } 3471 } else { 3472 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr)); 3473 tls[0] = dtv; 3474 dtv[0] = tls_dtv_generation; 3475 dtv[1] = tls_max_index; 3476 3477 for (obj = objs; obj; obj = obj->next) { 3478 if (obj->tlsoffset > 0) { 3479 addr = (Elf_Addr)tls + obj->tlsoffset; 3480 if (obj->tlsinitsize > 0) 3481 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3482 if (obj->tlssize > obj->tlsinitsize) 3483 memset((void*) (addr + obj->tlsinitsize), 0, 3484 obj->tlssize - obj->tlsinitsize); 3485 dtv[obj->tlsindex + 1] = addr; 3486 } 3487 } 3488 } 3489 3490 return (tcb); 3491 } 3492 3493 void 3494 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3495 { 3496 Elf_Addr *dtv; 3497 Elf_Addr tlsstart, tlsend; 3498 int dtvsize, i; 3499 3500 assert(tcbsize >= TLS_TCB_SIZE); 3501 3502 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3503 tlsend = tlsstart + tls_static_space; 3504 3505 dtv = *(Elf_Addr **)tlsstart; 3506 dtvsize = dtv[1]; 3507 for (i = 0; i < dtvsize; i++) { 3508 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3509 free((void*)dtv[i+2]); 3510 } 3511 } 3512 free(dtv); 3513 free(tcb); 3514 } 3515 3516 #endif 3517 3518 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \ 3519 defined(__arm__) || defined(__mips__) 3520 3521 /* 3522 * Allocate Static TLS using the Variant II method. 3523 */ 3524 void * 3525 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3526 { 3527 Obj_Entry *obj; 3528 size_t size; 3529 char *tls; 3530 Elf_Addr *dtv, *olddtv; 3531 Elf_Addr segbase, oldsegbase, addr; 3532 int i; 3533 3534 size = round(tls_static_space, tcbalign); 3535 3536 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3537 tls = calloc(1, size + tcbsize); 3538 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); 3539 3540 segbase = (Elf_Addr)(tls + size); 3541 ((Elf_Addr*)segbase)[0] = segbase; 3542 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3543 3544 dtv[0] = tls_dtv_generation; 3545 dtv[1] = tls_max_index; 3546 3547 if (oldtls) { 3548 /* 3549 * Copy the static TLS block over whole. 3550 */ 3551 oldsegbase = (Elf_Addr) oldtls; 3552 memcpy((void *)(segbase - tls_static_space), 3553 (const void *)(oldsegbase - tls_static_space), 3554 tls_static_space); 3555 3556 /* 3557 * If any dynamic TLS blocks have been created tls_get_addr(), 3558 * move them over. 3559 */ 3560 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3561 for (i = 0; i < olddtv[1]; i++) { 3562 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3563 dtv[i+2] = olddtv[i+2]; 3564 olddtv[i+2] = 0; 3565 } 3566 } 3567 3568 /* 3569 * We assume that this block was the one we created with 3570 * allocate_initial_tls(). 3571 */ 3572 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3573 } else { 3574 for (obj = objs; obj; obj = obj->next) { 3575 if (obj->tlsoffset) { 3576 addr = segbase - obj->tlsoffset; 3577 memset((void*) (addr + obj->tlsinitsize), 3578 0, obj->tlssize - obj->tlsinitsize); 3579 if (obj->tlsinit) 3580 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3581 dtv[obj->tlsindex + 1] = addr; 3582 } 3583 } 3584 } 3585 3586 return (void*) segbase; 3587 } 3588 3589 void 3590 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3591 { 3592 size_t size; 3593 Elf_Addr* dtv; 3594 int dtvsize, i; 3595 Elf_Addr tlsstart, tlsend; 3596 3597 /* 3598 * Figure out the size of the initial TLS block so that we can 3599 * find stuff which ___tls_get_addr() allocated dynamically. 3600 */ 3601 size = round(tls_static_space, tcbalign); 3602 3603 dtv = ((Elf_Addr**)tls)[1]; 3604 dtvsize = dtv[1]; 3605 tlsend = (Elf_Addr) tls; 3606 tlsstart = tlsend - size; 3607 for (i = 0; i < dtvsize; i++) { 3608 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3609 free((void*) dtv[i+2]); 3610 } 3611 } 3612 3613 free((void*) tlsstart); 3614 free((void*) dtv); 3615 } 3616 3617 #endif 3618 3619 /* 3620 * Allocate TLS block for module with given index. 3621 */ 3622 void * 3623 allocate_module_tls(int index) 3624 { 3625 Obj_Entry* obj; 3626 char* p; 3627 3628 for (obj = obj_list; obj; obj = obj->next) { 3629 if (obj->tlsindex == index) 3630 break; 3631 } 3632 if (!obj) { 3633 _rtld_error("Can't find module with TLS index %d", index); 3634 die(); 3635 } 3636 3637 p = malloc(obj->tlssize); 3638 if (p == NULL) { 3639 _rtld_error("Cannot allocate TLS block for index %d", index); 3640 die(); 3641 } 3642 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3643 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3644 3645 return p; 3646 } 3647 3648 bool 3649 allocate_tls_offset(Obj_Entry *obj) 3650 { 3651 size_t off; 3652 3653 if (obj->tls_done) 3654 return true; 3655 3656 if (obj->tlssize == 0) { 3657 obj->tls_done = true; 3658 return true; 3659 } 3660 3661 if (obj->tlsindex == 1) 3662 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 3663 else 3664 off = calculate_tls_offset(tls_last_offset, tls_last_size, 3665 obj->tlssize, obj->tlsalign); 3666 3667 /* 3668 * If we have already fixed the size of the static TLS block, we 3669 * must stay within that size. When allocating the static TLS, we 3670 * leave a small amount of space spare to be used for dynamically 3671 * loading modules which use static TLS. 3672 */ 3673 if (tls_static_space) { 3674 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 3675 return false; 3676 } 3677 3678 tls_last_offset = obj->tlsoffset = off; 3679 tls_last_size = obj->tlssize; 3680 obj->tls_done = true; 3681 3682 return true; 3683 } 3684 3685 void 3686 free_tls_offset(Obj_Entry *obj) 3687 { 3688 3689 /* 3690 * If we were the last thing to allocate out of the static TLS 3691 * block, we give our space back to the 'allocator'. This is a 3692 * simplistic workaround to allow libGL.so.1 to be loaded and 3693 * unloaded multiple times. 3694 */ 3695 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 3696 == calculate_tls_end(tls_last_offset, tls_last_size)) { 3697 tls_last_offset -= obj->tlssize; 3698 tls_last_size = 0; 3699 } 3700 } 3701 3702 void * 3703 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 3704 { 3705 void *ret; 3706 RtldLockState lockstate; 3707 3708 wlock_acquire(rtld_bind_lock, &lockstate); 3709 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 3710 lock_release(rtld_bind_lock, &lockstate); 3711 return (ret); 3712 } 3713 3714 void 3715 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3716 { 3717 RtldLockState lockstate; 3718 3719 wlock_acquire(rtld_bind_lock, &lockstate); 3720 free_tls(tcb, tcbsize, tcbalign); 3721 lock_release(rtld_bind_lock, &lockstate); 3722 } 3723 3724 static void 3725 object_add_name(Obj_Entry *obj, const char *name) 3726 { 3727 Name_Entry *entry; 3728 size_t len; 3729 3730 len = strlen(name); 3731 entry = malloc(sizeof(Name_Entry) + len); 3732 3733 if (entry != NULL) { 3734 strcpy(entry->name, name); 3735 STAILQ_INSERT_TAIL(&obj->names, entry, link); 3736 } 3737 } 3738 3739 static int 3740 object_match_name(const Obj_Entry *obj, const char *name) 3741 { 3742 Name_Entry *entry; 3743 3744 STAILQ_FOREACH(entry, &obj->names, link) { 3745 if (strcmp(name, entry->name) == 0) 3746 return (1); 3747 } 3748 return (0); 3749 } 3750 3751 static Obj_Entry * 3752 locate_dependency(const Obj_Entry *obj, const char *name) 3753 { 3754 const Objlist_Entry *entry; 3755 const Needed_Entry *needed; 3756 3757 STAILQ_FOREACH(entry, &list_main, link) { 3758 if (object_match_name(entry->obj, name)) 3759 return entry->obj; 3760 } 3761 3762 for (needed = obj->needed; needed != NULL; needed = needed->next) { 3763 if (strcmp(obj->strtab + needed->name, name) == 0 || 3764 (needed->obj != NULL && object_match_name(needed->obj, name))) { 3765 /* 3766 * If there is DT_NEEDED for the name we are looking for, 3767 * we are all set. Note that object might not be found if 3768 * dependency was not loaded yet, so the function can 3769 * return NULL here. This is expected and handled 3770 * properly by the caller. 3771 */ 3772 return (needed->obj); 3773 } 3774 } 3775 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 3776 obj->path, name); 3777 die(); 3778 } 3779 3780 static int 3781 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 3782 const Elf_Vernaux *vna) 3783 { 3784 const Elf_Verdef *vd; 3785 const char *vername; 3786 3787 vername = refobj->strtab + vna->vna_name; 3788 vd = depobj->verdef; 3789 if (vd == NULL) { 3790 _rtld_error("%s: version %s required by %s not defined", 3791 depobj->path, vername, refobj->path); 3792 return (-1); 3793 } 3794 for (;;) { 3795 if (vd->vd_version != VER_DEF_CURRENT) { 3796 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3797 depobj->path, vd->vd_version); 3798 return (-1); 3799 } 3800 if (vna->vna_hash == vd->vd_hash) { 3801 const Elf_Verdaux *aux = (const Elf_Verdaux *) 3802 ((char *)vd + vd->vd_aux); 3803 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 3804 return (0); 3805 } 3806 if (vd->vd_next == 0) 3807 break; 3808 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3809 } 3810 if (vna->vna_flags & VER_FLG_WEAK) 3811 return (0); 3812 _rtld_error("%s: version %s required by %s not found", 3813 depobj->path, vername, refobj->path); 3814 return (-1); 3815 } 3816 3817 static int 3818 rtld_verify_object_versions(Obj_Entry *obj) 3819 { 3820 const Elf_Verneed *vn; 3821 const Elf_Verdef *vd; 3822 const Elf_Verdaux *vda; 3823 const Elf_Vernaux *vna; 3824 const Obj_Entry *depobj; 3825 int maxvernum, vernum; 3826 3827 maxvernum = 0; 3828 /* 3829 * Walk over defined and required version records and figure out 3830 * max index used by any of them. Do very basic sanity checking 3831 * while there. 3832 */ 3833 vn = obj->verneed; 3834 while (vn != NULL) { 3835 if (vn->vn_version != VER_NEED_CURRENT) { 3836 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 3837 obj->path, vn->vn_version); 3838 return (-1); 3839 } 3840 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3841 for (;;) { 3842 vernum = VER_NEED_IDX(vna->vna_other); 3843 if (vernum > maxvernum) 3844 maxvernum = vernum; 3845 if (vna->vna_next == 0) 3846 break; 3847 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3848 } 3849 if (vn->vn_next == 0) 3850 break; 3851 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3852 } 3853 3854 vd = obj->verdef; 3855 while (vd != NULL) { 3856 if (vd->vd_version != VER_DEF_CURRENT) { 3857 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 3858 obj->path, vd->vd_version); 3859 return (-1); 3860 } 3861 vernum = VER_DEF_IDX(vd->vd_ndx); 3862 if (vernum > maxvernum) 3863 maxvernum = vernum; 3864 if (vd->vd_next == 0) 3865 break; 3866 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3867 } 3868 3869 if (maxvernum == 0) 3870 return (0); 3871 3872 /* 3873 * Store version information in array indexable by version index. 3874 * Verify that object version requirements are satisfied along the 3875 * way. 3876 */ 3877 obj->vernum = maxvernum + 1; 3878 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry)); 3879 3880 vd = obj->verdef; 3881 while (vd != NULL) { 3882 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 3883 vernum = VER_DEF_IDX(vd->vd_ndx); 3884 assert(vernum <= maxvernum); 3885 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 3886 obj->vertab[vernum].hash = vd->vd_hash; 3887 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 3888 obj->vertab[vernum].file = NULL; 3889 obj->vertab[vernum].flags = 0; 3890 } 3891 if (vd->vd_next == 0) 3892 break; 3893 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 3894 } 3895 3896 vn = obj->verneed; 3897 while (vn != NULL) { 3898 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 3899 if (depobj == NULL) 3900 return (-1); 3901 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 3902 for (;;) { 3903 if (check_object_provided_version(obj, depobj, vna)) 3904 return (-1); 3905 vernum = VER_NEED_IDX(vna->vna_other); 3906 assert(vernum <= maxvernum); 3907 obj->vertab[vernum].hash = vna->vna_hash; 3908 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 3909 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 3910 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 3911 VER_INFO_HIDDEN : 0; 3912 if (vna->vna_next == 0) 3913 break; 3914 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 3915 } 3916 if (vn->vn_next == 0) 3917 break; 3918 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 3919 } 3920 return 0; 3921 } 3922 3923 static int 3924 rtld_verify_versions(const Objlist *objlist) 3925 { 3926 Objlist_Entry *entry; 3927 int rc; 3928 3929 rc = 0; 3930 STAILQ_FOREACH(entry, objlist, link) { 3931 /* 3932 * Skip dummy objects or objects that have their version requirements 3933 * already checked. 3934 */ 3935 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 3936 continue; 3937 if (rtld_verify_object_versions(entry->obj) == -1) { 3938 rc = -1; 3939 if (ld_tracing == NULL) 3940 break; 3941 } 3942 } 3943 if (rc == 0 || ld_tracing != NULL) 3944 rc = rtld_verify_object_versions(&obj_rtld); 3945 return rc; 3946 } 3947 3948 const Ver_Entry * 3949 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 3950 { 3951 Elf_Versym vernum; 3952 3953 if (obj->vertab) { 3954 vernum = VER_NDX(obj->versyms[symnum]); 3955 if (vernum >= obj->vernum) { 3956 _rtld_error("%s: symbol %s has wrong verneed value %d", 3957 obj->path, obj->strtab + symnum, vernum); 3958 } else if (obj->vertab[vernum].hash != 0) { 3959 return &obj->vertab[vernum]; 3960 } 3961 } 3962 return NULL; 3963 } 3964 3965 int 3966 _rtld_get_stack_prot(void) 3967 { 3968 3969 return (stack_prot); 3970 } 3971 3972 static void 3973 map_stacks_exec(RtldLockState *lockstate) 3974 { 3975 void (*thr_map_stacks_exec)(void); 3976 3977 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 3978 return; 3979 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 3980 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 3981 if (thr_map_stacks_exec != NULL) { 3982 stack_prot |= PROT_EXEC; 3983 thr_map_stacks_exec(); 3984 } 3985 } 3986 3987 void 3988 symlook_init(SymLook *dst, const char *name) 3989 { 3990 3991 bzero(dst, sizeof(*dst)); 3992 dst->name = name; 3993 dst->hash = elf_hash(name); 3994 } 3995 3996 static void 3997 symlook_init_from_req(SymLook *dst, const SymLook *src) 3998 { 3999 4000 dst->name = src->name; 4001 dst->hash = src->hash; 4002 dst->ventry = src->ventry; 4003 dst->flags = src->flags; 4004 dst->defobj_out = NULL; 4005 dst->sym_out = NULL; 4006 dst->lockstate = src->lockstate; 4007 } 4008 4009 /* 4010 * Overrides for libc_pic-provided functions. 4011 */ 4012 4013 int 4014 __getosreldate(void) 4015 { 4016 size_t len; 4017 int oid[2]; 4018 int error, osrel; 4019 4020 if (osreldate != 0) 4021 return (osreldate); 4022 4023 oid[0] = CTL_KERN; 4024 oid[1] = KERN_OSRELDATE; 4025 osrel = 0; 4026 len = sizeof(osrel); 4027 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4028 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4029 osreldate = osrel; 4030 return (osreldate); 4031 } 4032 4033 /* 4034 * No unresolved symbols for rtld. 4035 */ 4036 void 4037 __pthread_cxa_finalize(struct dl_phdr_info *a) 4038 { 4039 } 4040