1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37 #ifndef __GNUC__ 38 #error "GCC is needed to compile this file" 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/mount.h> 43 #include <sys/mman.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/uio.h> 47 #include <sys/utsname.h> 48 #include <sys/ktrace.h> 49 50 #include <dlfcn.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <stdarg.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 #include "debug.h" 61 #include "rtld.h" 62 #include "libmap.h" 63 #include "rtld_tls.h" 64 #include "rtld_printf.h" 65 #include "notes.h" 66 67 #ifndef COMPAT_32BIT 68 #define PATH_RTLD "/libexec/ld-elf.so.1" 69 #else 70 #define PATH_RTLD "/libexec/ld-elf32.so.1" 71 #endif 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 /* 78 * Function declarations. 79 */ 80 static const char *basename(const char *); 81 static void die(void) __dead2; 82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 83 const Elf_Dyn **); 84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 85 static void digest_dynamic(Obj_Entry *, int); 86 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 87 static Obj_Entry *dlcheck(void *); 88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *); 97 static const char *gethints(void); 98 static void init_dag(Obj_Entry *); 99 static void init_rtld(caddr_t, Elf_Auxinfo **); 100 static void initlist_add_neededs(Needed_Entry *, Objlist *); 101 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 102 static void linkmap_add(Obj_Entry *); 103 static void linkmap_delete(Obj_Entry *); 104 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 105 static void unload_filtees(Obj_Entry *); 106 static int load_needed_objects(Obj_Entry *, int); 107 static int load_preload_objects(void); 108 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 109 static void map_stacks_exec(RtldLockState *); 110 static Obj_Entry *obj_from_addr(const void *); 111 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 112 static void objlist_call_init(Objlist *, RtldLockState *); 113 static void objlist_clear(Objlist *); 114 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 115 static void objlist_init(Objlist *); 116 static void objlist_push_head(Objlist *, Obj_Entry *); 117 static void objlist_push_tail(Objlist *, Obj_Entry *); 118 static void objlist_remove(Objlist *, Obj_Entry *); 119 static void *path_enumerate(const char *, path_enum_proc, void *); 120 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 121 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 122 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 123 int flags, RtldLockState *lockstate); 124 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 125 RtldLockState *); 126 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 127 int flags, RtldLockState *lockstate); 128 static int rtld_dirname(const char *, char *); 129 static int rtld_dirname_abs(const char *, char *); 130 static void *rtld_dlopen(const char *name, int fd, int mode); 131 static void rtld_exit(void); 132 static char *search_library_path(const char *, const char *); 133 static const void **get_program_var_addr(const char *, RtldLockState *); 134 static void set_program_var(const char *, const void *); 135 static int symlook_default(SymLook *, const Obj_Entry *refobj); 136 static int symlook_global(SymLook *, DoneList *); 137 static void symlook_init_from_req(SymLook *, const SymLook *); 138 static int symlook_list(SymLook *, const Objlist *, DoneList *); 139 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 140 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 141 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 142 static void trace_loaded_objects(Obj_Entry *); 143 static void unlink_object(Obj_Entry *); 144 static void unload_object(Obj_Entry *); 145 static void unref_dag(Obj_Entry *); 146 static void ref_dag(Obj_Entry *); 147 static int origin_subst_one(char **, const char *, const char *, 148 const char *, char *); 149 static char *origin_subst(const char *, const char *); 150 static void preinit_main(void); 151 static int rtld_verify_versions(const Objlist *); 152 static int rtld_verify_object_versions(Obj_Entry *); 153 static void object_add_name(Obj_Entry *, const char *); 154 static int object_match_name(const Obj_Entry *, const char *); 155 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 156 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 157 struct dl_phdr_info *phdr_info); 158 static uint32_t gnu_hash(const char *); 159 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 160 const unsigned long); 161 162 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 163 164 /* 165 * Data declarations. 166 */ 167 static char *error_message; /* Message for dlerror(), or NULL */ 168 struct r_debug r_debug; /* for GDB; */ 169 static bool libmap_disable; /* Disable libmap */ 170 static bool ld_loadfltr; /* Immediate filters processing */ 171 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 172 static bool trust; /* False for setuid and setgid programs */ 173 static bool dangerous_ld_env; /* True if environment variables have been 174 used to affect the libraries loaded */ 175 static char *ld_bind_now; /* Environment variable for immediate binding */ 176 static char *ld_debug; /* Environment variable for debugging */ 177 static char *ld_library_path; /* Environment variable for search path */ 178 static char *ld_preload; /* Environment variable for libraries to 179 load first */ 180 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 181 static char *ld_tracing; /* Called from ldd to print libs */ 182 static char *ld_utrace; /* Use utrace() to log events. */ 183 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 184 static Obj_Entry **obj_tail; /* Link field of last object in list */ 185 static Obj_Entry *obj_main; /* The main program shared object */ 186 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 187 static unsigned int obj_count; /* Number of objects in obj_list */ 188 static unsigned int obj_loads; /* Number of objects in obj_list */ 189 190 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 191 STAILQ_HEAD_INITIALIZER(list_global); 192 static Objlist list_main = /* Objects loaded at program startup */ 193 STAILQ_HEAD_INITIALIZER(list_main); 194 static Objlist list_fini = /* Objects needing fini() calls */ 195 STAILQ_HEAD_INITIALIZER(list_fini); 196 197 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 198 199 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 200 201 extern Elf_Dyn _DYNAMIC; 202 #pragma weak _DYNAMIC 203 #ifndef RTLD_IS_DYNAMIC 204 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 205 #endif 206 207 int osreldate, pagesize; 208 209 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 210 211 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 212 static int max_stack_flags; 213 214 /* 215 * Global declarations normally provided by crt1. The dynamic linker is 216 * not built with crt1, so we have to provide them ourselves. 217 */ 218 char *__progname; 219 char **environ; 220 221 /* 222 * Used to pass argc, argv to init functions. 223 */ 224 int main_argc; 225 char **main_argv; 226 227 /* 228 * Globals to control TLS allocation. 229 */ 230 size_t tls_last_offset; /* Static TLS offset of last module */ 231 size_t tls_last_size; /* Static TLS size of last module */ 232 size_t tls_static_space; /* Static TLS space allocated */ 233 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 234 int tls_max_index = 1; /* Largest module index allocated */ 235 236 /* 237 * Fill in a DoneList with an allocation large enough to hold all of 238 * the currently-loaded objects. Keep this as a macro since it calls 239 * alloca and we want that to occur within the scope of the caller. 240 */ 241 #define donelist_init(dlp) \ 242 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 243 assert((dlp)->objs != NULL), \ 244 (dlp)->num_alloc = obj_count, \ 245 (dlp)->num_used = 0) 246 247 #define UTRACE_DLOPEN_START 1 248 #define UTRACE_DLOPEN_STOP 2 249 #define UTRACE_DLCLOSE_START 3 250 #define UTRACE_DLCLOSE_STOP 4 251 #define UTRACE_LOAD_OBJECT 5 252 #define UTRACE_UNLOAD_OBJECT 6 253 #define UTRACE_ADD_RUNDEP 7 254 #define UTRACE_PRELOAD_FINISHED 8 255 #define UTRACE_INIT_CALL 9 256 #define UTRACE_FINI_CALL 10 257 258 struct utrace_rtld { 259 char sig[4]; /* 'RTLD' */ 260 int event; 261 void *handle; 262 void *mapbase; /* Used for 'parent' and 'init/fini' */ 263 size_t mapsize; 264 int refcnt; /* Used for 'mode' */ 265 char name[MAXPATHLEN]; 266 }; 267 268 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 269 if (ld_utrace != NULL) \ 270 ld_utrace_log(e, h, mb, ms, r, n); \ 271 } while (0) 272 273 static void 274 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 275 int refcnt, const char *name) 276 { 277 struct utrace_rtld ut; 278 279 ut.sig[0] = 'R'; 280 ut.sig[1] = 'T'; 281 ut.sig[2] = 'L'; 282 ut.sig[3] = 'D'; 283 ut.event = event; 284 ut.handle = handle; 285 ut.mapbase = mapbase; 286 ut.mapsize = mapsize; 287 ut.refcnt = refcnt; 288 bzero(ut.name, sizeof(ut.name)); 289 if (name) 290 strlcpy(ut.name, name, sizeof(ut.name)); 291 utrace(&ut, sizeof(ut)); 292 } 293 294 /* 295 * Main entry point for dynamic linking. The first argument is the 296 * stack pointer. The stack is expected to be laid out as described 297 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 298 * Specifically, the stack pointer points to a word containing 299 * ARGC. Following that in the stack is a null-terminated sequence 300 * of pointers to argument strings. Then comes a null-terminated 301 * sequence of pointers to environment strings. Finally, there is a 302 * sequence of "auxiliary vector" entries. 303 * 304 * The second argument points to a place to store the dynamic linker's 305 * exit procedure pointer and the third to a place to store the main 306 * program's object. 307 * 308 * The return value is the main program's entry point. 309 */ 310 func_ptr_type 311 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 312 { 313 Elf_Auxinfo *aux_info[AT_COUNT]; 314 int i; 315 int argc; 316 char **argv; 317 char **env; 318 Elf_Auxinfo *aux; 319 Elf_Auxinfo *auxp; 320 const char *argv0; 321 Objlist_Entry *entry; 322 Obj_Entry *obj; 323 Obj_Entry **preload_tail; 324 Objlist initlist; 325 RtldLockState lockstate; 326 int mib[2]; 327 size_t len; 328 329 /* 330 * On entry, the dynamic linker itself has not been relocated yet. 331 * Be very careful not to reference any global data until after 332 * init_rtld has returned. It is OK to reference file-scope statics 333 * and string constants, and to call static and global functions. 334 */ 335 336 /* Find the auxiliary vector on the stack. */ 337 argc = *sp++; 338 argv = (char **) sp; 339 sp += argc + 1; /* Skip over arguments and NULL terminator */ 340 env = (char **) sp; 341 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 342 ; 343 aux = (Elf_Auxinfo *) sp; 344 345 /* Digest the auxiliary vector. */ 346 for (i = 0; i < AT_COUNT; i++) 347 aux_info[i] = NULL; 348 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 349 if (auxp->a_type < AT_COUNT) 350 aux_info[auxp->a_type] = auxp; 351 } 352 353 /* Initialize and relocate ourselves. */ 354 assert(aux_info[AT_BASE] != NULL); 355 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 356 357 __progname = obj_rtld.path; 358 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 359 environ = env; 360 main_argc = argc; 361 main_argv = argv; 362 363 if (aux_info[AT_CANARY] != NULL && 364 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 365 i = aux_info[AT_CANARYLEN]->a_un.a_val; 366 if (i > sizeof(__stack_chk_guard)) 367 i = sizeof(__stack_chk_guard); 368 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 369 } else { 370 mib[0] = CTL_KERN; 371 mib[1] = KERN_ARND; 372 373 len = sizeof(__stack_chk_guard); 374 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 375 len != sizeof(__stack_chk_guard)) { 376 /* If sysctl was unsuccessful, use the "terminator canary". */ 377 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 378 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 379 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 380 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 381 } 382 } 383 384 trust = !issetugid(); 385 386 ld_bind_now = getenv(LD_ "BIND_NOW"); 387 /* 388 * If the process is tainted, then we un-set the dangerous environment 389 * variables. The process will be marked as tainted until setuid(2) 390 * is called. If any child process calls setuid(2) we do not want any 391 * future processes to honor the potentially un-safe variables. 392 */ 393 if (!trust) { 394 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 395 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 396 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 397 unsetenv(LD_ "LOADFLTR")) { 398 _rtld_error("environment corrupt; aborting"); 399 die(); 400 } 401 } 402 ld_debug = getenv(LD_ "DEBUG"); 403 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 404 libmap_override = getenv(LD_ "LIBMAP"); 405 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 406 ld_preload = getenv(LD_ "PRELOAD"); 407 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 408 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 409 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 410 (ld_library_path != NULL) || (ld_preload != NULL) || 411 (ld_elf_hints_path != NULL) || ld_loadfltr; 412 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 413 ld_utrace = getenv(LD_ "UTRACE"); 414 415 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 416 ld_elf_hints_path = _PATH_ELF_HINTS; 417 418 if (ld_debug != NULL && *ld_debug != '\0') 419 debug = 1; 420 dbg("%s is initialized, base address = %p", __progname, 421 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 422 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 423 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 424 425 dbg("initializing thread locks"); 426 lockdflt_init(); 427 428 /* 429 * Load the main program, or process its program header if it is 430 * already loaded. 431 */ 432 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 433 int fd = aux_info[AT_EXECFD]->a_un.a_val; 434 dbg("loading main program"); 435 obj_main = map_object(fd, argv0, NULL); 436 close(fd); 437 if (obj_main == NULL) 438 die(); 439 max_stack_flags = obj->stack_flags; 440 } else { /* Main program already loaded. */ 441 const Elf_Phdr *phdr; 442 int phnum; 443 caddr_t entry; 444 445 dbg("processing main program's program header"); 446 assert(aux_info[AT_PHDR] != NULL); 447 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 448 assert(aux_info[AT_PHNUM] != NULL); 449 phnum = aux_info[AT_PHNUM]->a_un.a_val; 450 assert(aux_info[AT_PHENT] != NULL); 451 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 452 assert(aux_info[AT_ENTRY] != NULL); 453 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 454 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 455 die(); 456 } 457 458 if (aux_info[AT_EXECPATH] != 0) { 459 char *kexecpath; 460 char buf[MAXPATHLEN]; 461 462 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 463 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 464 if (kexecpath[0] == '/') 465 obj_main->path = kexecpath; 466 else if (getcwd(buf, sizeof(buf)) == NULL || 467 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 468 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 469 obj_main->path = xstrdup(argv0); 470 else 471 obj_main->path = xstrdup(buf); 472 } else { 473 dbg("No AT_EXECPATH"); 474 obj_main->path = xstrdup(argv0); 475 } 476 dbg("obj_main path %s", obj_main->path); 477 obj_main->mainprog = true; 478 479 if (aux_info[AT_STACKPROT] != NULL && 480 aux_info[AT_STACKPROT]->a_un.a_val != 0) 481 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 482 483 /* 484 * Get the actual dynamic linker pathname from the executable if 485 * possible. (It should always be possible.) That ensures that 486 * gdb will find the right dynamic linker even if a non-standard 487 * one is being used. 488 */ 489 if (obj_main->interp != NULL && 490 strcmp(obj_main->interp, obj_rtld.path) != 0) { 491 free(obj_rtld.path); 492 obj_rtld.path = xstrdup(obj_main->interp); 493 __progname = obj_rtld.path; 494 } 495 496 digest_dynamic(obj_main, 0); 497 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 498 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 499 obj_main->dynsymcount); 500 501 linkmap_add(obj_main); 502 linkmap_add(&obj_rtld); 503 504 /* Link the main program into the list of objects. */ 505 *obj_tail = obj_main; 506 obj_tail = &obj_main->next; 507 obj_count++; 508 obj_loads++; 509 510 /* Initialize a fake symbol for resolving undefined weak references. */ 511 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 512 sym_zero.st_shndx = SHN_UNDEF; 513 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 514 515 if (!libmap_disable) 516 libmap_disable = (bool)lm_init(libmap_override); 517 518 dbg("loading LD_PRELOAD libraries"); 519 if (load_preload_objects() == -1) 520 die(); 521 preload_tail = obj_tail; 522 523 dbg("loading needed objects"); 524 if (load_needed_objects(obj_main, 0) == -1) 525 die(); 526 527 /* Make a list of all objects loaded at startup. */ 528 for (obj = obj_list; obj != NULL; obj = obj->next) { 529 objlist_push_tail(&list_main, obj); 530 obj->refcount++; 531 } 532 533 dbg("checking for required versions"); 534 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 535 die(); 536 537 if (ld_tracing) { /* We're done */ 538 trace_loaded_objects(obj_main); 539 exit(0); 540 } 541 542 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 543 dump_relocations(obj_main); 544 exit (0); 545 } 546 547 /* 548 * Processing tls relocations requires having the tls offsets 549 * initialized. Prepare offsets before starting initial 550 * relocation processing. 551 */ 552 dbg("initializing initial thread local storage offsets"); 553 STAILQ_FOREACH(entry, &list_main, link) { 554 /* 555 * Allocate all the initial objects out of the static TLS 556 * block even if they didn't ask for it. 557 */ 558 allocate_tls_offset(entry->obj); 559 } 560 561 if (relocate_objects(obj_main, 562 ld_bind_now != NULL && *ld_bind_now != '\0', 563 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 564 die(); 565 566 dbg("doing copy relocations"); 567 if (do_copy_relocations(obj_main) == -1) 568 die(); 569 570 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 571 dump_relocations(obj_main); 572 exit (0); 573 } 574 575 /* 576 * Setup TLS for main thread. This must be done after the 577 * relocations are processed, since tls initialization section 578 * might be the subject for relocations. 579 */ 580 dbg("initializing initial thread local storage"); 581 allocate_initial_tls(obj_list); 582 583 dbg("initializing key program variables"); 584 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 585 set_program_var("environ", env); 586 set_program_var("__elf_aux_vector", aux); 587 588 /* Make a list of init functions to call. */ 589 objlist_init(&initlist); 590 initlist_add_objects(obj_list, preload_tail, &initlist); 591 592 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 593 594 map_stacks_exec(NULL); 595 596 dbg("resolving ifuncs"); 597 if (resolve_objects_ifunc(obj_main, 598 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 599 NULL) == -1) 600 die(); 601 602 if (!obj_main->crt_no_init) { 603 /* 604 * Make sure we don't call the main program's init and fini 605 * functions for binaries linked with old crt1 which calls 606 * _init itself. 607 */ 608 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 609 obj_main->preinit_array = obj_main->init_array = 610 obj_main->fini_array = (Elf_Addr)NULL; 611 } 612 613 wlock_acquire(rtld_bind_lock, &lockstate); 614 if (obj_main->crt_no_init) 615 preinit_main(); 616 objlist_call_init(&initlist, &lockstate); 617 objlist_clear(&initlist); 618 dbg("loading filtees"); 619 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 620 if (ld_loadfltr || obj->z_loadfltr) 621 load_filtees(obj, 0, &lockstate); 622 } 623 lock_release(rtld_bind_lock, &lockstate); 624 625 dbg("transferring control to program entry point = %p", obj_main->entry); 626 627 /* Return the exit procedure and the program entry point. */ 628 *exit_proc = rtld_exit; 629 *objp = obj_main; 630 return (func_ptr_type) obj_main->entry; 631 } 632 633 void * 634 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 635 { 636 void *ptr; 637 Elf_Addr target; 638 639 ptr = (void *)make_function_pointer(def, obj); 640 target = ((Elf_Addr (*)(void))ptr)(); 641 return ((void *)target); 642 } 643 644 Elf_Addr 645 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 646 { 647 const Elf_Rel *rel; 648 const Elf_Sym *def; 649 const Obj_Entry *defobj; 650 Elf_Addr *where; 651 Elf_Addr target; 652 RtldLockState lockstate; 653 654 rlock_acquire(rtld_bind_lock, &lockstate); 655 if (sigsetjmp(lockstate.env, 0) != 0) 656 lock_upgrade(rtld_bind_lock, &lockstate); 657 if (obj->pltrel) 658 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 659 else 660 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 661 662 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 663 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 664 &lockstate); 665 if (def == NULL) 666 die(); 667 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 668 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 669 else 670 target = (Elf_Addr)(defobj->relocbase + def->st_value); 671 672 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 673 defobj->strtab + def->st_name, basename(obj->path), 674 (void *)target, basename(defobj->path)); 675 676 /* 677 * Write the new contents for the jmpslot. Note that depending on 678 * architecture, the value which we need to return back to the 679 * lazy binding trampoline may or may not be the target 680 * address. The value returned from reloc_jmpslot() is the value 681 * that the trampoline needs. 682 */ 683 target = reloc_jmpslot(where, target, defobj, obj, rel); 684 lock_release(rtld_bind_lock, &lockstate); 685 return target; 686 } 687 688 /* 689 * Error reporting function. Use it like printf. If formats the message 690 * into a buffer, and sets things up so that the next call to dlerror() 691 * will return the message. 692 */ 693 void 694 _rtld_error(const char *fmt, ...) 695 { 696 static char buf[512]; 697 va_list ap; 698 699 va_start(ap, fmt); 700 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 701 error_message = buf; 702 va_end(ap); 703 } 704 705 /* 706 * Return a dynamically-allocated copy of the current error message, if any. 707 */ 708 static char * 709 errmsg_save(void) 710 { 711 return error_message == NULL ? NULL : xstrdup(error_message); 712 } 713 714 /* 715 * Restore the current error message from a copy which was previously saved 716 * by errmsg_save(). The copy is freed. 717 */ 718 static void 719 errmsg_restore(char *saved_msg) 720 { 721 if (saved_msg == NULL) 722 error_message = NULL; 723 else { 724 _rtld_error("%s", saved_msg); 725 free(saved_msg); 726 } 727 } 728 729 static const char * 730 basename(const char *name) 731 { 732 const char *p = strrchr(name, '/'); 733 return p != NULL ? p + 1 : name; 734 } 735 736 static struct utsname uts; 737 738 static int 739 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 740 char *may_free) 741 { 742 const char *p, *p1; 743 char *res1; 744 int subst_len; 745 int kw_len; 746 747 res1 = *res = NULL; 748 p = real; 749 subst_len = kw_len = 0; 750 for (;;) { 751 p1 = strstr(p, kw); 752 if (p1 != NULL) { 753 if (subst_len == 0) { 754 subst_len = strlen(subst); 755 kw_len = strlen(kw); 756 } 757 if (*res == NULL) { 758 *res = xmalloc(PATH_MAX); 759 res1 = *res; 760 } 761 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 762 _rtld_error("Substitution of %s in %s cannot be performed", 763 kw, real); 764 if (may_free != NULL) 765 free(may_free); 766 free(res); 767 return (false); 768 } 769 memcpy(res1, p, p1 - p); 770 res1 += p1 - p; 771 memcpy(res1, subst, subst_len); 772 res1 += subst_len; 773 p = p1 + kw_len; 774 } else { 775 if (*res == NULL) { 776 if (may_free != NULL) 777 *res = may_free; 778 else 779 *res = xstrdup(real); 780 return (true); 781 } 782 *res1 = '\0'; 783 if (may_free != NULL) 784 free(may_free); 785 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 786 free(res); 787 return (false); 788 } 789 return (true); 790 } 791 } 792 } 793 794 static char * 795 origin_subst(const char *real, const char *origin_path) 796 { 797 char *res1, *res2, *res3, *res4; 798 799 if (uts.sysname[0] == '\0') { 800 if (uname(&uts) != 0) { 801 _rtld_error("utsname failed: %d", errno); 802 return (NULL); 803 } 804 } 805 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 806 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 807 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 808 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 809 return (NULL); 810 return (res4); 811 } 812 813 static void 814 die(void) 815 { 816 const char *msg = dlerror(); 817 818 if (msg == NULL) 819 msg = "Fatal error"; 820 rtld_fdputstr(STDERR_FILENO, msg); 821 rtld_fdputchar(STDERR_FILENO, '\n'); 822 _exit(1); 823 } 824 825 /* 826 * Process a shared object's DYNAMIC section, and save the important 827 * information in its Obj_Entry structure. 828 */ 829 static void 830 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 831 const Elf_Dyn **dyn_soname) 832 { 833 const Elf_Dyn *dynp; 834 Needed_Entry **needed_tail = &obj->needed; 835 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 836 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 837 const Elf_Hashelt *hashtab; 838 const Elf32_Word *hashval; 839 Elf32_Word bkt, nmaskwords; 840 int bloom_size32; 841 bool nmw_power2; 842 int plttype = DT_REL; 843 844 *dyn_rpath = NULL; 845 *dyn_soname = NULL; 846 847 obj->bind_now = false; 848 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 849 switch (dynp->d_tag) { 850 851 case DT_REL: 852 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 853 break; 854 855 case DT_RELSZ: 856 obj->relsize = dynp->d_un.d_val; 857 break; 858 859 case DT_RELENT: 860 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 861 break; 862 863 case DT_JMPREL: 864 obj->pltrel = (const Elf_Rel *) 865 (obj->relocbase + dynp->d_un.d_ptr); 866 break; 867 868 case DT_PLTRELSZ: 869 obj->pltrelsize = dynp->d_un.d_val; 870 break; 871 872 case DT_RELA: 873 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 874 break; 875 876 case DT_RELASZ: 877 obj->relasize = dynp->d_un.d_val; 878 break; 879 880 case DT_RELAENT: 881 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 882 break; 883 884 case DT_PLTREL: 885 plttype = dynp->d_un.d_val; 886 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 887 break; 888 889 case DT_SYMTAB: 890 obj->symtab = (const Elf_Sym *) 891 (obj->relocbase + dynp->d_un.d_ptr); 892 break; 893 894 case DT_SYMENT: 895 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 896 break; 897 898 case DT_STRTAB: 899 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 900 break; 901 902 case DT_STRSZ: 903 obj->strsize = dynp->d_un.d_val; 904 break; 905 906 case DT_VERNEED: 907 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 908 dynp->d_un.d_val); 909 break; 910 911 case DT_VERNEEDNUM: 912 obj->verneednum = dynp->d_un.d_val; 913 break; 914 915 case DT_VERDEF: 916 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 917 dynp->d_un.d_val); 918 break; 919 920 case DT_VERDEFNUM: 921 obj->verdefnum = dynp->d_un.d_val; 922 break; 923 924 case DT_VERSYM: 925 obj->versyms = (const Elf_Versym *)(obj->relocbase + 926 dynp->d_un.d_val); 927 break; 928 929 case DT_HASH: 930 { 931 hashtab = (const Elf_Hashelt *)(obj->relocbase + 932 dynp->d_un.d_ptr); 933 obj->nbuckets = hashtab[0]; 934 obj->nchains = hashtab[1]; 935 obj->buckets = hashtab + 2; 936 obj->chains = obj->buckets + obj->nbuckets; 937 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 938 obj->buckets != NULL; 939 } 940 break; 941 942 case DT_GNU_HASH: 943 { 944 hashtab = (const Elf_Hashelt *)(obj->relocbase + 945 dynp->d_un.d_ptr); 946 obj->nbuckets_gnu = hashtab[0]; 947 obj->symndx_gnu = hashtab[1]; 948 nmaskwords = hashtab[2]; 949 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 950 /* Number of bitmask words is required to be power of 2 */ 951 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 952 obj->maskwords_bm_gnu = nmaskwords - 1; 953 obj->shift2_gnu = hashtab[3]; 954 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 955 obj->buckets_gnu = hashtab + 4 + bloom_size32; 956 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 957 obj->symndx_gnu; 958 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 959 obj->buckets_gnu != NULL; 960 } 961 break; 962 963 case DT_NEEDED: 964 if (!obj->rtld) { 965 Needed_Entry *nep = NEW(Needed_Entry); 966 nep->name = dynp->d_un.d_val; 967 nep->obj = NULL; 968 nep->next = NULL; 969 970 *needed_tail = nep; 971 needed_tail = &nep->next; 972 } 973 break; 974 975 case DT_FILTER: 976 if (!obj->rtld) { 977 Needed_Entry *nep = NEW(Needed_Entry); 978 nep->name = dynp->d_un.d_val; 979 nep->obj = NULL; 980 nep->next = NULL; 981 982 *needed_filtees_tail = nep; 983 needed_filtees_tail = &nep->next; 984 } 985 break; 986 987 case DT_AUXILIARY: 988 if (!obj->rtld) { 989 Needed_Entry *nep = NEW(Needed_Entry); 990 nep->name = dynp->d_un.d_val; 991 nep->obj = NULL; 992 nep->next = NULL; 993 994 *needed_aux_filtees_tail = nep; 995 needed_aux_filtees_tail = &nep->next; 996 } 997 break; 998 999 case DT_PLTGOT: 1000 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1001 break; 1002 1003 case DT_TEXTREL: 1004 obj->textrel = true; 1005 break; 1006 1007 case DT_SYMBOLIC: 1008 obj->symbolic = true; 1009 break; 1010 1011 case DT_RPATH: 1012 case DT_RUNPATH: /* XXX: process separately */ 1013 /* 1014 * We have to wait until later to process this, because we 1015 * might not have gotten the address of the string table yet. 1016 */ 1017 *dyn_rpath = dynp; 1018 break; 1019 1020 case DT_SONAME: 1021 *dyn_soname = dynp; 1022 break; 1023 1024 case DT_INIT: 1025 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1026 break; 1027 1028 case DT_PREINIT_ARRAY: 1029 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1030 break; 1031 1032 case DT_PREINIT_ARRAYSZ: 1033 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1034 break; 1035 1036 case DT_INIT_ARRAY: 1037 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1038 break; 1039 1040 case DT_INIT_ARRAYSZ: 1041 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1042 break; 1043 1044 case DT_FINI: 1045 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1046 break; 1047 1048 case DT_FINI_ARRAY: 1049 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1050 break; 1051 1052 case DT_FINI_ARRAYSZ: 1053 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1054 break; 1055 1056 /* 1057 * Don't process DT_DEBUG on MIPS as the dynamic section 1058 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1059 */ 1060 1061 #ifndef __mips__ 1062 case DT_DEBUG: 1063 /* XXX - not implemented yet */ 1064 if (!early) 1065 dbg("Filling in DT_DEBUG entry"); 1066 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1067 break; 1068 #endif 1069 1070 case DT_FLAGS: 1071 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1072 obj->z_origin = true; 1073 if (dynp->d_un.d_val & DF_SYMBOLIC) 1074 obj->symbolic = true; 1075 if (dynp->d_un.d_val & DF_TEXTREL) 1076 obj->textrel = true; 1077 if (dynp->d_un.d_val & DF_BIND_NOW) 1078 obj->bind_now = true; 1079 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1080 ;*/ 1081 break; 1082 #ifdef __mips__ 1083 case DT_MIPS_LOCAL_GOTNO: 1084 obj->local_gotno = dynp->d_un.d_val; 1085 break; 1086 1087 case DT_MIPS_SYMTABNO: 1088 obj->symtabno = dynp->d_un.d_val; 1089 break; 1090 1091 case DT_MIPS_GOTSYM: 1092 obj->gotsym = dynp->d_un.d_val; 1093 break; 1094 1095 case DT_MIPS_RLD_MAP: 1096 #ifdef notyet 1097 if (!early) 1098 dbg("Filling in DT_DEBUG entry"); 1099 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1100 #endif 1101 break; 1102 #endif 1103 1104 case DT_FLAGS_1: 1105 if (dynp->d_un.d_val & DF_1_NOOPEN) 1106 obj->z_noopen = true; 1107 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1108 obj->z_origin = true; 1109 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1110 XXX ;*/ 1111 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1112 obj->bind_now = true; 1113 if (dynp->d_un.d_val & DF_1_NODELETE) 1114 obj->z_nodelete = true; 1115 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1116 obj->z_loadfltr = true; 1117 break; 1118 1119 default: 1120 if (!early) { 1121 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1122 (long)dynp->d_tag); 1123 } 1124 break; 1125 } 1126 } 1127 1128 obj->traced = false; 1129 1130 if (plttype == DT_RELA) { 1131 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1132 obj->pltrel = NULL; 1133 obj->pltrelasize = obj->pltrelsize; 1134 obj->pltrelsize = 0; 1135 } 1136 1137 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1138 if (obj->valid_hash_sysv) 1139 obj->dynsymcount = obj->nchains; 1140 else if (obj->valid_hash_gnu) { 1141 obj->dynsymcount = 0; 1142 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1143 if (obj->buckets_gnu[bkt] == 0) 1144 continue; 1145 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1146 do 1147 obj->dynsymcount++; 1148 while ((*hashval++ & 1u) == 0); 1149 } 1150 obj->dynsymcount += obj->symndx_gnu; 1151 } 1152 } 1153 1154 static void 1155 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1156 const Elf_Dyn *dyn_soname) 1157 { 1158 1159 if (obj->z_origin && obj->origin_path == NULL) { 1160 obj->origin_path = xmalloc(PATH_MAX); 1161 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1162 die(); 1163 } 1164 1165 if (dyn_rpath != NULL) { 1166 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1167 if (obj->z_origin) 1168 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1169 } 1170 1171 if (dyn_soname != NULL) 1172 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1173 } 1174 1175 static void 1176 digest_dynamic(Obj_Entry *obj, int early) 1177 { 1178 const Elf_Dyn *dyn_rpath; 1179 const Elf_Dyn *dyn_soname; 1180 1181 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1182 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1183 } 1184 1185 /* 1186 * Process a shared object's program header. This is used only for the 1187 * main program, when the kernel has already loaded the main program 1188 * into memory before calling the dynamic linker. It creates and 1189 * returns an Obj_Entry structure. 1190 */ 1191 static Obj_Entry * 1192 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1193 { 1194 Obj_Entry *obj; 1195 const Elf_Phdr *phlimit = phdr + phnum; 1196 const Elf_Phdr *ph; 1197 Elf_Addr note_start, note_end; 1198 int nsegs = 0; 1199 1200 obj = obj_new(); 1201 for (ph = phdr; ph < phlimit; ph++) { 1202 if (ph->p_type != PT_PHDR) 1203 continue; 1204 1205 obj->phdr = phdr; 1206 obj->phsize = ph->p_memsz; 1207 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1208 break; 1209 } 1210 1211 obj->stack_flags = PF_X | PF_R | PF_W; 1212 1213 for (ph = phdr; ph < phlimit; ph++) { 1214 switch (ph->p_type) { 1215 1216 case PT_INTERP: 1217 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1218 break; 1219 1220 case PT_LOAD: 1221 if (nsegs == 0) { /* First load segment */ 1222 obj->vaddrbase = trunc_page(ph->p_vaddr); 1223 obj->mapbase = obj->vaddrbase + obj->relocbase; 1224 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1225 obj->vaddrbase; 1226 } else { /* Last load segment */ 1227 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1228 obj->vaddrbase; 1229 } 1230 nsegs++; 1231 break; 1232 1233 case PT_DYNAMIC: 1234 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1235 break; 1236 1237 case PT_TLS: 1238 obj->tlsindex = 1; 1239 obj->tlssize = ph->p_memsz; 1240 obj->tlsalign = ph->p_align; 1241 obj->tlsinitsize = ph->p_filesz; 1242 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1243 break; 1244 1245 case PT_GNU_STACK: 1246 obj->stack_flags = ph->p_flags; 1247 break; 1248 1249 case PT_GNU_RELRO: 1250 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1251 obj->relro_size = round_page(ph->p_memsz); 1252 break; 1253 1254 case PT_NOTE: 1255 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1256 note_end = note_start + ph->p_filesz; 1257 digest_notes(obj, note_start, note_end); 1258 break; 1259 } 1260 } 1261 if (nsegs < 1) { 1262 _rtld_error("%s: too few PT_LOAD segments", path); 1263 return NULL; 1264 } 1265 1266 obj->entry = entry; 1267 return obj; 1268 } 1269 1270 void 1271 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1272 { 1273 const Elf_Note *note; 1274 const char *note_name; 1275 uintptr_t p; 1276 1277 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1278 note = (const Elf_Note *)((const char *)(note + 1) + 1279 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1280 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1281 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1282 note->n_descsz != sizeof(int32_t)) 1283 continue; 1284 if (note->n_type != ABI_NOTETYPE && 1285 note->n_type != CRT_NOINIT_NOTETYPE) 1286 continue; 1287 note_name = (const char *)(note + 1); 1288 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1289 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1290 continue; 1291 switch (note->n_type) { 1292 case ABI_NOTETYPE: 1293 /* FreeBSD osrel note */ 1294 p = (uintptr_t)(note + 1); 1295 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1296 obj->osrel = *(const int32_t *)(p); 1297 dbg("note osrel %d", obj->osrel); 1298 break; 1299 case CRT_NOINIT_NOTETYPE: 1300 /* FreeBSD 'crt does not call init' note */ 1301 obj->crt_no_init = true; 1302 dbg("note crt_no_init"); 1303 break; 1304 } 1305 } 1306 } 1307 1308 static Obj_Entry * 1309 dlcheck(void *handle) 1310 { 1311 Obj_Entry *obj; 1312 1313 for (obj = obj_list; obj != NULL; obj = obj->next) 1314 if (obj == (Obj_Entry *) handle) 1315 break; 1316 1317 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1318 _rtld_error("Invalid shared object handle %p", handle); 1319 return NULL; 1320 } 1321 return obj; 1322 } 1323 1324 /* 1325 * If the given object is already in the donelist, return true. Otherwise 1326 * add the object to the list and return false. 1327 */ 1328 static bool 1329 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1330 { 1331 unsigned int i; 1332 1333 for (i = 0; i < dlp->num_used; i++) 1334 if (dlp->objs[i] == obj) 1335 return true; 1336 /* 1337 * Our donelist allocation should always be sufficient. But if 1338 * our threads locking isn't working properly, more shared objects 1339 * could have been loaded since we allocated the list. That should 1340 * never happen, but we'll handle it properly just in case it does. 1341 */ 1342 if (dlp->num_used < dlp->num_alloc) 1343 dlp->objs[dlp->num_used++] = obj; 1344 return false; 1345 } 1346 1347 /* 1348 * Hash function for symbol table lookup. Don't even think about changing 1349 * this. It is specified by the System V ABI. 1350 */ 1351 unsigned long 1352 elf_hash(const char *name) 1353 { 1354 const unsigned char *p = (const unsigned char *) name; 1355 unsigned long h = 0; 1356 unsigned long g; 1357 1358 while (*p != '\0') { 1359 h = (h << 4) + *p++; 1360 if ((g = h & 0xf0000000) != 0) 1361 h ^= g >> 24; 1362 h &= ~g; 1363 } 1364 return h; 1365 } 1366 1367 /* 1368 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1369 * unsigned in case it's implemented with a wider type. 1370 */ 1371 static uint32_t 1372 gnu_hash(const char *s) 1373 { 1374 uint32_t h; 1375 unsigned char c; 1376 1377 h = 5381; 1378 for (c = *s; c != '\0'; c = *++s) 1379 h = h * 33 + c; 1380 return (h & 0xffffffff); 1381 } 1382 1383 /* 1384 * Find the library with the given name, and return its full pathname. 1385 * The returned string is dynamically allocated. Generates an error 1386 * message and returns NULL if the library cannot be found. 1387 * 1388 * If the second argument is non-NULL, then it refers to an already- 1389 * loaded shared object, whose library search path will be searched. 1390 * 1391 * The search order is: 1392 * LD_LIBRARY_PATH 1393 * rpath in the referencing file 1394 * ldconfig hints 1395 * /lib:/usr/lib 1396 */ 1397 static char * 1398 find_library(const char *xname, const Obj_Entry *refobj) 1399 { 1400 char *pathname; 1401 char *name; 1402 1403 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1404 if (xname[0] != '/' && !trust) { 1405 _rtld_error("Absolute pathname required for shared object \"%s\"", 1406 xname); 1407 return NULL; 1408 } 1409 if (refobj != NULL && refobj->z_origin) 1410 return origin_subst(xname, refobj->origin_path); 1411 else 1412 return xstrdup(xname); 1413 } 1414 1415 if (libmap_disable || (refobj == NULL) || 1416 (name = lm_find(refobj->path, xname)) == NULL) 1417 name = (char *)xname; 1418 1419 dbg(" Searching for \"%s\"", name); 1420 1421 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1422 (refobj != NULL && 1423 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1424 (pathname = search_library_path(name, gethints())) != NULL || 1425 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1426 return pathname; 1427 1428 if(refobj != NULL && refobj->path != NULL) { 1429 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1430 name, basename(refobj->path)); 1431 } else { 1432 _rtld_error("Shared object \"%s\" not found", name); 1433 } 1434 return NULL; 1435 } 1436 1437 /* 1438 * Given a symbol number in a referencing object, find the corresponding 1439 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1440 * no definition was found. Returns a pointer to the Obj_Entry of the 1441 * defining object via the reference parameter DEFOBJ_OUT. 1442 */ 1443 const Elf_Sym * 1444 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1445 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1446 RtldLockState *lockstate) 1447 { 1448 const Elf_Sym *ref; 1449 const Elf_Sym *def; 1450 const Obj_Entry *defobj; 1451 SymLook req; 1452 const char *name; 1453 int res; 1454 1455 /* 1456 * If we have already found this symbol, get the information from 1457 * the cache. 1458 */ 1459 if (symnum >= refobj->dynsymcount) 1460 return NULL; /* Bad object */ 1461 if (cache != NULL && cache[symnum].sym != NULL) { 1462 *defobj_out = cache[symnum].obj; 1463 return cache[symnum].sym; 1464 } 1465 1466 ref = refobj->symtab + symnum; 1467 name = refobj->strtab + ref->st_name; 1468 def = NULL; 1469 defobj = NULL; 1470 1471 /* 1472 * We don't have to do a full scale lookup if the symbol is local. 1473 * We know it will bind to the instance in this load module; to 1474 * which we already have a pointer (ie ref). By not doing a lookup, 1475 * we not only improve performance, but it also avoids unresolvable 1476 * symbols when local symbols are not in the hash table. This has 1477 * been seen with the ia64 toolchain. 1478 */ 1479 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1480 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1481 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1482 symnum); 1483 } 1484 symlook_init(&req, name); 1485 req.flags = flags; 1486 req.ventry = fetch_ventry(refobj, symnum); 1487 req.lockstate = lockstate; 1488 res = symlook_default(&req, refobj); 1489 if (res == 0) { 1490 def = req.sym_out; 1491 defobj = req.defobj_out; 1492 } 1493 } else { 1494 def = ref; 1495 defobj = refobj; 1496 } 1497 1498 /* 1499 * If we found no definition and the reference is weak, treat the 1500 * symbol as having the value zero. 1501 */ 1502 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1503 def = &sym_zero; 1504 defobj = obj_main; 1505 } 1506 1507 if (def != NULL) { 1508 *defobj_out = defobj; 1509 /* Record the information in the cache to avoid subsequent lookups. */ 1510 if (cache != NULL) { 1511 cache[symnum].sym = def; 1512 cache[symnum].obj = defobj; 1513 } 1514 } else { 1515 if (refobj != &obj_rtld) 1516 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1517 } 1518 return def; 1519 } 1520 1521 /* 1522 * Return the search path from the ldconfig hints file, reading it if 1523 * necessary. Returns NULL if there are problems with the hints file, 1524 * or if the search path there is empty. 1525 */ 1526 static const char * 1527 gethints(void) 1528 { 1529 static char *hints; 1530 1531 if (hints == NULL) { 1532 int fd; 1533 struct elfhints_hdr hdr; 1534 char *p; 1535 1536 /* Keep from trying again in case the hints file is bad. */ 1537 hints = ""; 1538 1539 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1540 return NULL; 1541 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1542 hdr.magic != ELFHINTS_MAGIC || 1543 hdr.version != 1) { 1544 close(fd); 1545 return NULL; 1546 } 1547 p = xmalloc(hdr.dirlistlen + 1); 1548 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1549 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1550 free(p); 1551 close(fd); 1552 return NULL; 1553 } 1554 hints = p; 1555 close(fd); 1556 } 1557 return hints[0] != '\0' ? hints : NULL; 1558 } 1559 1560 static void 1561 init_dag(Obj_Entry *root) 1562 { 1563 const Needed_Entry *needed; 1564 const Objlist_Entry *elm; 1565 DoneList donelist; 1566 1567 if (root->dag_inited) 1568 return; 1569 donelist_init(&donelist); 1570 1571 /* Root object belongs to own DAG. */ 1572 objlist_push_tail(&root->dldags, root); 1573 objlist_push_tail(&root->dagmembers, root); 1574 donelist_check(&donelist, root); 1575 1576 /* 1577 * Add dependencies of root object to DAG in breadth order 1578 * by exploiting the fact that each new object get added 1579 * to the tail of the dagmembers list. 1580 */ 1581 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1582 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1583 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1584 continue; 1585 objlist_push_tail(&needed->obj->dldags, root); 1586 objlist_push_tail(&root->dagmembers, needed->obj); 1587 } 1588 } 1589 root->dag_inited = true; 1590 } 1591 1592 /* 1593 * Initialize the dynamic linker. The argument is the address at which 1594 * the dynamic linker has been mapped into memory. The primary task of 1595 * this function is to relocate the dynamic linker. 1596 */ 1597 static void 1598 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1599 { 1600 Obj_Entry objtmp; /* Temporary rtld object */ 1601 const Elf_Dyn *dyn_rpath; 1602 const Elf_Dyn *dyn_soname; 1603 1604 /* 1605 * Conjure up an Obj_Entry structure for the dynamic linker. 1606 * 1607 * The "path" member can't be initialized yet because string constants 1608 * cannot yet be accessed. Below we will set it correctly. 1609 */ 1610 memset(&objtmp, 0, sizeof(objtmp)); 1611 objtmp.path = NULL; 1612 objtmp.rtld = true; 1613 objtmp.mapbase = mapbase; 1614 #ifdef PIC 1615 objtmp.relocbase = mapbase; 1616 #endif 1617 if (RTLD_IS_DYNAMIC()) { 1618 objtmp.dynamic = rtld_dynamic(&objtmp); 1619 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1620 assert(objtmp.needed == NULL); 1621 #if !defined(__mips__) 1622 /* MIPS has a bogus DT_TEXTREL. */ 1623 assert(!objtmp.textrel); 1624 #endif 1625 1626 /* 1627 * Temporarily put the dynamic linker entry into the object list, so 1628 * that symbols can be found. 1629 */ 1630 1631 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1632 } 1633 1634 /* Initialize the object list. */ 1635 obj_tail = &obj_list; 1636 1637 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1638 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1639 1640 if (aux_info[AT_PAGESZ] != NULL) 1641 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1642 if (aux_info[AT_OSRELDATE] != NULL) 1643 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1644 1645 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1646 1647 /* Replace the path with a dynamically allocated copy. */ 1648 obj_rtld.path = xstrdup(PATH_RTLD); 1649 1650 r_debug.r_brk = r_debug_state; 1651 r_debug.r_state = RT_CONSISTENT; 1652 } 1653 1654 /* 1655 * Add the init functions from a needed object list (and its recursive 1656 * needed objects) to "list". This is not used directly; it is a helper 1657 * function for initlist_add_objects(). The write lock must be held 1658 * when this function is called. 1659 */ 1660 static void 1661 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1662 { 1663 /* Recursively process the successor needed objects. */ 1664 if (needed->next != NULL) 1665 initlist_add_neededs(needed->next, list); 1666 1667 /* Process the current needed object. */ 1668 if (needed->obj != NULL) 1669 initlist_add_objects(needed->obj, &needed->obj->next, list); 1670 } 1671 1672 /* 1673 * Scan all of the DAGs rooted in the range of objects from "obj" to 1674 * "tail" and add their init functions to "list". This recurses over 1675 * the DAGs and ensure the proper init ordering such that each object's 1676 * needed libraries are initialized before the object itself. At the 1677 * same time, this function adds the objects to the global finalization 1678 * list "list_fini" in the opposite order. The write lock must be 1679 * held when this function is called. 1680 */ 1681 static void 1682 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1683 { 1684 1685 if (obj->init_scanned || obj->init_done) 1686 return; 1687 obj->init_scanned = true; 1688 1689 /* Recursively process the successor objects. */ 1690 if (&obj->next != tail) 1691 initlist_add_objects(obj->next, tail, list); 1692 1693 /* Recursively process the needed objects. */ 1694 if (obj->needed != NULL) 1695 initlist_add_neededs(obj->needed, list); 1696 if (obj->needed_filtees != NULL) 1697 initlist_add_neededs(obj->needed_filtees, list); 1698 if (obj->needed_aux_filtees != NULL) 1699 initlist_add_neededs(obj->needed_aux_filtees, list); 1700 1701 /* Add the object to the init list. */ 1702 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1703 obj->init_array != (Elf_Addr)NULL) 1704 objlist_push_tail(list, obj); 1705 1706 /* Add the object to the global fini list in the reverse order. */ 1707 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1708 && !obj->on_fini_list) { 1709 objlist_push_head(&list_fini, obj); 1710 obj->on_fini_list = true; 1711 } 1712 } 1713 1714 #ifndef FPTR_TARGET 1715 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1716 #endif 1717 1718 static void 1719 free_needed_filtees(Needed_Entry *n) 1720 { 1721 Needed_Entry *needed, *needed1; 1722 1723 for (needed = n; needed != NULL; needed = needed->next) { 1724 if (needed->obj != NULL) { 1725 dlclose(needed->obj); 1726 needed->obj = NULL; 1727 } 1728 } 1729 for (needed = n; needed != NULL; needed = needed1) { 1730 needed1 = needed->next; 1731 free(needed); 1732 } 1733 } 1734 1735 static void 1736 unload_filtees(Obj_Entry *obj) 1737 { 1738 1739 free_needed_filtees(obj->needed_filtees); 1740 obj->needed_filtees = NULL; 1741 free_needed_filtees(obj->needed_aux_filtees); 1742 obj->needed_aux_filtees = NULL; 1743 obj->filtees_loaded = false; 1744 } 1745 1746 static void 1747 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 1748 RtldLockState *lockstate) 1749 { 1750 1751 for (; needed != NULL; needed = needed->next) { 1752 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 1753 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1754 RTLD_LOCAL, lockstate); 1755 } 1756 } 1757 1758 static void 1759 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1760 { 1761 1762 lock_restart_for_upgrade(lockstate); 1763 if (!obj->filtees_loaded) { 1764 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 1765 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 1766 obj->filtees_loaded = true; 1767 } 1768 } 1769 1770 static int 1771 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1772 { 1773 Obj_Entry *obj1; 1774 1775 for (; needed != NULL; needed = needed->next) { 1776 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 1777 flags & ~RTLD_LO_NOLOAD); 1778 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1779 return (-1); 1780 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1781 dbg("obj %s nodelete", obj1->path); 1782 init_dag(obj1); 1783 ref_dag(obj1); 1784 obj1->ref_nodel = true; 1785 } 1786 } 1787 return (0); 1788 } 1789 1790 /* 1791 * Given a shared object, traverse its list of needed objects, and load 1792 * each of them. Returns 0 on success. Generates an error message and 1793 * returns -1 on failure. 1794 */ 1795 static int 1796 load_needed_objects(Obj_Entry *first, int flags) 1797 { 1798 Obj_Entry *obj; 1799 1800 for (obj = first; obj != NULL; obj = obj->next) { 1801 if (process_needed(obj, obj->needed, flags) == -1) 1802 return (-1); 1803 } 1804 return (0); 1805 } 1806 1807 static int 1808 load_preload_objects(void) 1809 { 1810 char *p = ld_preload; 1811 static const char delim[] = " \t:;"; 1812 1813 if (p == NULL) 1814 return 0; 1815 1816 p += strspn(p, delim); 1817 while (*p != '\0') { 1818 size_t len = strcspn(p, delim); 1819 char savech; 1820 1821 savech = p[len]; 1822 p[len] = '\0'; 1823 if (load_object(p, -1, NULL, 0) == NULL) 1824 return -1; /* XXX - cleanup */ 1825 p[len] = savech; 1826 p += len; 1827 p += strspn(p, delim); 1828 } 1829 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1830 return 0; 1831 } 1832 1833 static const char * 1834 printable_path(const char *path) 1835 { 1836 1837 return (path == NULL ? "<unknown>" : path); 1838 } 1839 1840 /* 1841 * Load a shared object into memory, if it is not already loaded. The 1842 * object may be specified by name or by user-supplied file descriptor 1843 * fd_u. In the later case, the fd_u descriptor is not closed, but its 1844 * duplicate is. 1845 * 1846 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1847 * on failure. 1848 */ 1849 static Obj_Entry * 1850 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 1851 { 1852 Obj_Entry *obj; 1853 int fd; 1854 struct stat sb; 1855 char *path; 1856 1857 if (name != NULL) { 1858 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1859 if (object_match_name(obj, name)) 1860 return (obj); 1861 } 1862 1863 path = find_library(name, refobj); 1864 if (path == NULL) 1865 return (NULL); 1866 } else 1867 path = NULL; 1868 1869 /* 1870 * If we didn't find a match by pathname, or the name is not 1871 * supplied, open the file and check again by device and inode. 1872 * This avoids false mismatches caused by multiple links or ".." 1873 * in pathnames. 1874 * 1875 * To avoid a race, we open the file and use fstat() rather than 1876 * using stat(). 1877 */ 1878 fd = -1; 1879 if (fd_u == -1) { 1880 if ((fd = open(path, O_RDONLY)) == -1) { 1881 _rtld_error("Cannot open \"%s\"", path); 1882 free(path); 1883 return (NULL); 1884 } 1885 } else { 1886 fd = dup(fd_u); 1887 if (fd == -1) { 1888 _rtld_error("Cannot dup fd"); 1889 free(path); 1890 return (NULL); 1891 } 1892 } 1893 if (fstat(fd, &sb) == -1) { 1894 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 1895 close(fd); 1896 free(path); 1897 return NULL; 1898 } 1899 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1900 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1901 break; 1902 if (obj != NULL && name != NULL) { 1903 object_add_name(obj, name); 1904 free(path); 1905 close(fd); 1906 return obj; 1907 } 1908 if (flags & RTLD_LO_NOLOAD) { 1909 free(path); 1910 close(fd); 1911 return (NULL); 1912 } 1913 1914 /* First use of this object, so we must map it in */ 1915 obj = do_load_object(fd, name, path, &sb, flags); 1916 if (obj == NULL) 1917 free(path); 1918 close(fd); 1919 1920 return obj; 1921 } 1922 1923 static Obj_Entry * 1924 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1925 int flags) 1926 { 1927 Obj_Entry *obj; 1928 struct statfs fs; 1929 1930 /* 1931 * but first, make sure that environment variables haven't been 1932 * used to circumvent the noexec flag on a filesystem. 1933 */ 1934 if (dangerous_ld_env) { 1935 if (fstatfs(fd, &fs) != 0) { 1936 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 1937 return NULL; 1938 } 1939 if (fs.f_flags & MNT_NOEXEC) { 1940 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1941 return NULL; 1942 } 1943 } 1944 dbg("loading \"%s\"", printable_path(path)); 1945 obj = map_object(fd, printable_path(path), sbp); 1946 if (obj == NULL) 1947 return NULL; 1948 1949 /* 1950 * If DT_SONAME is present in the object, digest_dynamic2 already 1951 * added it to the object names. 1952 */ 1953 if (name != NULL) 1954 object_add_name(obj, name); 1955 obj->path = path; 1956 digest_dynamic(obj, 0); 1957 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 1958 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 1959 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1960 RTLD_LO_DLOPEN) { 1961 dbg("refusing to load non-loadable \"%s\"", obj->path); 1962 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1963 munmap(obj->mapbase, obj->mapsize); 1964 obj_free(obj); 1965 return (NULL); 1966 } 1967 1968 *obj_tail = obj; 1969 obj_tail = &obj->next; 1970 obj_count++; 1971 obj_loads++; 1972 linkmap_add(obj); /* for GDB & dlinfo() */ 1973 max_stack_flags |= obj->stack_flags; 1974 1975 dbg(" %p .. %p: %s", obj->mapbase, 1976 obj->mapbase + obj->mapsize - 1, obj->path); 1977 if (obj->textrel) 1978 dbg(" WARNING: %s has impure text", obj->path); 1979 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1980 obj->path); 1981 1982 return obj; 1983 } 1984 1985 static Obj_Entry * 1986 obj_from_addr(const void *addr) 1987 { 1988 Obj_Entry *obj; 1989 1990 for (obj = obj_list; obj != NULL; obj = obj->next) { 1991 if (addr < (void *) obj->mapbase) 1992 continue; 1993 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1994 return obj; 1995 } 1996 return NULL; 1997 } 1998 1999 static void 2000 preinit_main(void) 2001 { 2002 Elf_Addr *preinit_addr; 2003 int index; 2004 2005 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2006 if (preinit_addr == NULL) 2007 return; 2008 2009 for (index = 0; index < obj_main->preinit_array_num; index++) { 2010 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2011 dbg("calling preinit function for %s at %p", obj_main->path, 2012 (void *)preinit_addr[index]); 2013 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2014 0, 0, obj_main->path); 2015 call_init_pointer(obj_main, preinit_addr[index]); 2016 } 2017 } 2018 } 2019 2020 /* 2021 * Call the finalization functions for each of the objects in "list" 2022 * belonging to the DAG of "root" and referenced once. If NULL "root" 2023 * is specified, every finalization function will be called regardless 2024 * of the reference count and the list elements won't be freed. All of 2025 * the objects are expected to have non-NULL fini functions. 2026 */ 2027 static void 2028 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2029 { 2030 Objlist_Entry *elm; 2031 char *saved_msg; 2032 Elf_Addr *fini_addr; 2033 int index; 2034 2035 assert(root == NULL || root->refcount == 1); 2036 2037 /* 2038 * Preserve the current error message since a fini function might 2039 * call into the dynamic linker and overwrite it. 2040 */ 2041 saved_msg = errmsg_save(); 2042 do { 2043 STAILQ_FOREACH(elm, list, link) { 2044 if (root != NULL && (elm->obj->refcount != 1 || 2045 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2046 continue; 2047 /* Remove object from fini list to prevent recursive invocation. */ 2048 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2049 /* 2050 * XXX: If a dlopen() call references an object while the 2051 * fini function is in progress, we might end up trying to 2052 * unload the referenced object in dlclose() or the object 2053 * won't be unloaded although its fini function has been 2054 * called. 2055 */ 2056 lock_release(rtld_bind_lock, lockstate); 2057 2058 /* 2059 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2060 * When this happens, DT_FINI_ARRAY is processed first. 2061 */ 2062 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2063 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2064 for (index = elm->obj->fini_array_num - 1; index >= 0; 2065 index--) { 2066 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2067 dbg("calling fini function for %s at %p", 2068 elm->obj->path, (void *)fini_addr[index]); 2069 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2070 (void *)fini_addr[index], 0, 0, elm->obj->path); 2071 call_initfini_pointer(elm->obj, fini_addr[index]); 2072 } 2073 } 2074 } 2075 if (elm->obj->fini != (Elf_Addr)NULL) { 2076 dbg("calling fini function for %s at %p", elm->obj->path, 2077 (void *)elm->obj->fini); 2078 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2079 0, 0, elm->obj->path); 2080 call_initfini_pointer(elm->obj, elm->obj->fini); 2081 } 2082 wlock_acquire(rtld_bind_lock, lockstate); 2083 /* No need to free anything if process is going down. */ 2084 if (root != NULL) 2085 free(elm); 2086 /* 2087 * We must restart the list traversal after every fini call 2088 * because a dlclose() call from the fini function or from 2089 * another thread might have modified the reference counts. 2090 */ 2091 break; 2092 } 2093 } while (elm != NULL); 2094 errmsg_restore(saved_msg); 2095 } 2096 2097 /* 2098 * Call the initialization functions for each of the objects in 2099 * "list". All of the objects are expected to have non-NULL init 2100 * functions. 2101 */ 2102 static void 2103 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2104 { 2105 Objlist_Entry *elm; 2106 Obj_Entry *obj; 2107 char *saved_msg; 2108 Elf_Addr *init_addr; 2109 int index; 2110 2111 /* 2112 * Clean init_scanned flag so that objects can be rechecked and 2113 * possibly initialized earlier if any of vectors called below 2114 * cause the change by using dlopen. 2115 */ 2116 for (obj = obj_list; obj != NULL; obj = obj->next) 2117 obj->init_scanned = false; 2118 2119 /* 2120 * Preserve the current error message since an init function might 2121 * call into the dynamic linker and overwrite it. 2122 */ 2123 saved_msg = errmsg_save(); 2124 STAILQ_FOREACH(elm, list, link) { 2125 if (elm->obj->init_done) /* Initialized early. */ 2126 continue; 2127 /* 2128 * Race: other thread might try to use this object before current 2129 * one completes the initilization. Not much can be done here 2130 * without better locking. 2131 */ 2132 elm->obj->init_done = true; 2133 lock_release(rtld_bind_lock, lockstate); 2134 2135 /* 2136 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2137 * When this happens, DT_INIT is processed first. 2138 */ 2139 if (elm->obj->init != (Elf_Addr)NULL) { 2140 dbg("calling init function for %s at %p", elm->obj->path, 2141 (void *)elm->obj->init); 2142 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2143 0, 0, elm->obj->path); 2144 call_initfini_pointer(elm->obj, elm->obj->init); 2145 } 2146 init_addr = (Elf_Addr *)elm->obj->init_array; 2147 if (init_addr != NULL) { 2148 for (index = 0; index < elm->obj->init_array_num; index++) { 2149 if (init_addr[index] != 0 && init_addr[index] != 1) { 2150 dbg("calling init function for %s at %p", elm->obj->path, 2151 (void *)init_addr[index]); 2152 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2153 (void *)init_addr[index], 0, 0, elm->obj->path); 2154 call_init_pointer(elm->obj, init_addr[index]); 2155 } 2156 } 2157 } 2158 wlock_acquire(rtld_bind_lock, lockstate); 2159 } 2160 errmsg_restore(saved_msg); 2161 } 2162 2163 static void 2164 objlist_clear(Objlist *list) 2165 { 2166 Objlist_Entry *elm; 2167 2168 while (!STAILQ_EMPTY(list)) { 2169 elm = STAILQ_FIRST(list); 2170 STAILQ_REMOVE_HEAD(list, link); 2171 free(elm); 2172 } 2173 } 2174 2175 static Objlist_Entry * 2176 objlist_find(Objlist *list, const Obj_Entry *obj) 2177 { 2178 Objlist_Entry *elm; 2179 2180 STAILQ_FOREACH(elm, list, link) 2181 if (elm->obj == obj) 2182 return elm; 2183 return NULL; 2184 } 2185 2186 static void 2187 objlist_init(Objlist *list) 2188 { 2189 STAILQ_INIT(list); 2190 } 2191 2192 static void 2193 objlist_push_head(Objlist *list, Obj_Entry *obj) 2194 { 2195 Objlist_Entry *elm; 2196 2197 elm = NEW(Objlist_Entry); 2198 elm->obj = obj; 2199 STAILQ_INSERT_HEAD(list, elm, link); 2200 } 2201 2202 static void 2203 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2204 { 2205 Objlist_Entry *elm; 2206 2207 elm = NEW(Objlist_Entry); 2208 elm->obj = obj; 2209 STAILQ_INSERT_TAIL(list, elm, link); 2210 } 2211 2212 static void 2213 objlist_remove(Objlist *list, Obj_Entry *obj) 2214 { 2215 Objlist_Entry *elm; 2216 2217 if ((elm = objlist_find(list, obj)) != NULL) { 2218 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2219 free(elm); 2220 } 2221 } 2222 2223 /* 2224 * Relocate dag rooted in the specified object. 2225 * Returns 0 on success, or -1 on failure. 2226 */ 2227 2228 static int 2229 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2230 int flags, RtldLockState *lockstate) 2231 { 2232 Objlist_Entry *elm; 2233 int error; 2234 2235 error = 0; 2236 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2237 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2238 lockstate); 2239 if (error == -1) 2240 break; 2241 } 2242 return (error); 2243 } 2244 2245 /* 2246 * Relocate single object. 2247 * Returns 0 on success, or -1 on failure. 2248 */ 2249 static int 2250 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2251 int flags, RtldLockState *lockstate) 2252 { 2253 2254 if (obj->relocated) 2255 return (0); 2256 obj->relocated = true; 2257 if (obj != rtldobj) 2258 dbg("relocating \"%s\"", obj->path); 2259 2260 if (obj->symtab == NULL || obj->strtab == NULL || 2261 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2262 _rtld_error("%s: Shared object has no run-time symbol table", 2263 obj->path); 2264 return (-1); 2265 } 2266 2267 if (obj->textrel) { 2268 /* There are relocations to the write-protected text segment. */ 2269 if (mprotect(obj->mapbase, obj->textsize, 2270 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2271 _rtld_error("%s: Cannot write-enable text segment: %s", 2272 obj->path, rtld_strerror(errno)); 2273 return (-1); 2274 } 2275 } 2276 2277 /* Process the non-PLT relocations. */ 2278 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2279 return (-1); 2280 2281 if (obj->textrel) { /* Re-protected the text segment. */ 2282 if (mprotect(obj->mapbase, obj->textsize, 2283 PROT_READ|PROT_EXEC) == -1) { 2284 _rtld_error("%s: Cannot write-protect text segment: %s", 2285 obj->path, rtld_strerror(errno)); 2286 return (-1); 2287 } 2288 } 2289 2290 2291 /* Set the special PLT or GOT entries. */ 2292 init_pltgot(obj); 2293 2294 /* Process the PLT relocations. */ 2295 if (reloc_plt(obj) == -1) 2296 return (-1); 2297 /* Relocate the jump slots if we are doing immediate binding. */ 2298 if (obj->bind_now || bind_now) 2299 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2300 return (-1); 2301 2302 if (obj->relro_size > 0) { 2303 if (mprotect(obj->relro_page, obj->relro_size, 2304 PROT_READ) == -1) { 2305 _rtld_error("%s: Cannot enforce relro protection: %s", 2306 obj->path, rtld_strerror(errno)); 2307 return (-1); 2308 } 2309 } 2310 2311 /* 2312 * Set up the magic number and version in the Obj_Entry. These 2313 * were checked in the crt1.o from the original ElfKit, so we 2314 * set them for backward compatibility. 2315 */ 2316 obj->magic = RTLD_MAGIC; 2317 obj->version = RTLD_VERSION; 2318 2319 return (0); 2320 } 2321 2322 /* 2323 * Relocate newly-loaded shared objects. The argument is a pointer to 2324 * the Obj_Entry for the first such object. All objects from the first 2325 * to the end of the list of objects are relocated. Returns 0 on success, 2326 * or -1 on failure. 2327 */ 2328 static int 2329 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2330 int flags, RtldLockState *lockstate) 2331 { 2332 Obj_Entry *obj; 2333 int error; 2334 2335 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2336 error = relocate_object(obj, bind_now, rtldobj, flags, 2337 lockstate); 2338 if (error == -1) 2339 break; 2340 } 2341 return (error); 2342 } 2343 2344 /* 2345 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2346 * referencing STT_GNU_IFUNC symbols is postponed till the other 2347 * relocations are done. The indirect functions specified as 2348 * ifunc are allowed to call other symbols, so we need to have 2349 * objects relocated before asking for resolution from indirects. 2350 * 2351 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2352 * instead of the usual lazy handling of PLT slots. It is 2353 * consistent with how GNU does it. 2354 */ 2355 static int 2356 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2357 RtldLockState *lockstate) 2358 { 2359 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2360 return (-1); 2361 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2362 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2363 return (-1); 2364 return (0); 2365 } 2366 2367 static int 2368 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2369 RtldLockState *lockstate) 2370 { 2371 Obj_Entry *obj; 2372 2373 for (obj = first; obj != NULL; obj = obj->next) { 2374 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2375 return (-1); 2376 } 2377 return (0); 2378 } 2379 2380 static int 2381 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2382 RtldLockState *lockstate) 2383 { 2384 Objlist_Entry *elm; 2385 2386 STAILQ_FOREACH(elm, list, link) { 2387 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2388 lockstate) == -1) 2389 return (-1); 2390 } 2391 return (0); 2392 } 2393 2394 /* 2395 * Cleanup procedure. It will be called (by the atexit mechanism) just 2396 * before the process exits. 2397 */ 2398 static void 2399 rtld_exit(void) 2400 { 2401 RtldLockState lockstate; 2402 2403 wlock_acquire(rtld_bind_lock, &lockstate); 2404 dbg("rtld_exit()"); 2405 objlist_call_fini(&list_fini, NULL, &lockstate); 2406 /* No need to remove the items from the list, since we are exiting. */ 2407 if (!libmap_disable) 2408 lm_fini(); 2409 lock_release(rtld_bind_lock, &lockstate); 2410 } 2411 2412 static void * 2413 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2414 { 2415 #ifdef COMPAT_32BIT 2416 const char *trans; 2417 #endif 2418 if (path == NULL) 2419 return (NULL); 2420 2421 path += strspn(path, ":;"); 2422 while (*path != '\0') { 2423 size_t len; 2424 char *res; 2425 2426 len = strcspn(path, ":;"); 2427 #ifdef COMPAT_32BIT 2428 trans = lm_findn(NULL, path, len); 2429 if (trans) 2430 res = callback(trans, strlen(trans), arg); 2431 else 2432 #endif 2433 res = callback(path, len, arg); 2434 2435 if (res != NULL) 2436 return (res); 2437 2438 path += len; 2439 path += strspn(path, ":;"); 2440 } 2441 2442 return (NULL); 2443 } 2444 2445 struct try_library_args { 2446 const char *name; 2447 size_t namelen; 2448 char *buffer; 2449 size_t buflen; 2450 }; 2451 2452 static void * 2453 try_library_path(const char *dir, size_t dirlen, void *param) 2454 { 2455 struct try_library_args *arg; 2456 2457 arg = param; 2458 if (*dir == '/' || trust) { 2459 char *pathname; 2460 2461 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2462 return (NULL); 2463 2464 pathname = arg->buffer; 2465 strncpy(pathname, dir, dirlen); 2466 pathname[dirlen] = '/'; 2467 strcpy(pathname + dirlen + 1, arg->name); 2468 2469 dbg(" Trying \"%s\"", pathname); 2470 if (access(pathname, F_OK) == 0) { /* We found it */ 2471 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2472 strcpy(pathname, arg->buffer); 2473 return (pathname); 2474 } 2475 } 2476 return (NULL); 2477 } 2478 2479 static char * 2480 search_library_path(const char *name, const char *path) 2481 { 2482 char *p; 2483 struct try_library_args arg; 2484 2485 if (path == NULL) 2486 return NULL; 2487 2488 arg.name = name; 2489 arg.namelen = strlen(name); 2490 arg.buffer = xmalloc(PATH_MAX); 2491 arg.buflen = PATH_MAX; 2492 2493 p = path_enumerate(path, try_library_path, &arg); 2494 2495 free(arg.buffer); 2496 2497 return (p); 2498 } 2499 2500 int 2501 dlclose(void *handle) 2502 { 2503 Obj_Entry *root; 2504 RtldLockState lockstate; 2505 2506 wlock_acquire(rtld_bind_lock, &lockstate); 2507 root = dlcheck(handle); 2508 if (root == NULL) { 2509 lock_release(rtld_bind_lock, &lockstate); 2510 return -1; 2511 } 2512 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2513 root->path); 2514 2515 /* Unreference the object and its dependencies. */ 2516 root->dl_refcount--; 2517 2518 if (root->refcount == 1) { 2519 /* 2520 * The object will be no longer referenced, so we must unload it. 2521 * First, call the fini functions. 2522 */ 2523 objlist_call_fini(&list_fini, root, &lockstate); 2524 2525 unref_dag(root); 2526 2527 /* Finish cleaning up the newly-unreferenced objects. */ 2528 GDB_STATE(RT_DELETE,&root->linkmap); 2529 unload_object(root); 2530 GDB_STATE(RT_CONSISTENT,NULL); 2531 } else 2532 unref_dag(root); 2533 2534 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2535 lock_release(rtld_bind_lock, &lockstate); 2536 return 0; 2537 } 2538 2539 char * 2540 dlerror(void) 2541 { 2542 char *msg = error_message; 2543 error_message = NULL; 2544 return msg; 2545 } 2546 2547 /* 2548 * This function is deprecated and has no effect. 2549 */ 2550 void 2551 dllockinit(void *context, 2552 void *(*lock_create)(void *context), 2553 void (*rlock_acquire)(void *lock), 2554 void (*wlock_acquire)(void *lock), 2555 void (*lock_release)(void *lock), 2556 void (*lock_destroy)(void *lock), 2557 void (*context_destroy)(void *context)) 2558 { 2559 static void *cur_context; 2560 static void (*cur_context_destroy)(void *); 2561 2562 /* Just destroy the context from the previous call, if necessary. */ 2563 if (cur_context_destroy != NULL) 2564 cur_context_destroy(cur_context); 2565 cur_context = context; 2566 cur_context_destroy = context_destroy; 2567 } 2568 2569 void * 2570 dlopen(const char *name, int mode) 2571 { 2572 2573 return (rtld_dlopen(name, -1, mode)); 2574 } 2575 2576 void * 2577 fdlopen(int fd, int mode) 2578 { 2579 2580 return (rtld_dlopen(NULL, fd, mode)); 2581 } 2582 2583 static void * 2584 rtld_dlopen(const char *name, int fd, int mode) 2585 { 2586 RtldLockState lockstate; 2587 int lo_flags; 2588 2589 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2590 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2591 if (ld_tracing != NULL) { 2592 rlock_acquire(rtld_bind_lock, &lockstate); 2593 if (sigsetjmp(lockstate.env, 0) != 0) 2594 lock_upgrade(rtld_bind_lock, &lockstate); 2595 environ = (char **)*get_program_var_addr("environ", &lockstate); 2596 lock_release(rtld_bind_lock, &lockstate); 2597 } 2598 lo_flags = RTLD_LO_DLOPEN; 2599 if (mode & RTLD_NODELETE) 2600 lo_flags |= RTLD_LO_NODELETE; 2601 if (mode & RTLD_NOLOAD) 2602 lo_flags |= RTLD_LO_NOLOAD; 2603 if (ld_tracing != NULL) 2604 lo_flags |= RTLD_LO_TRACE; 2605 2606 return (dlopen_object(name, fd, obj_main, lo_flags, 2607 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2608 } 2609 2610 static void 2611 dlopen_cleanup(Obj_Entry *obj) 2612 { 2613 2614 obj->dl_refcount--; 2615 unref_dag(obj); 2616 if (obj->refcount == 0) 2617 unload_object(obj); 2618 } 2619 2620 static Obj_Entry * 2621 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2622 int mode, RtldLockState *lockstate) 2623 { 2624 Obj_Entry **old_obj_tail; 2625 Obj_Entry *obj; 2626 Objlist initlist; 2627 RtldLockState mlockstate; 2628 int result; 2629 2630 objlist_init(&initlist); 2631 2632 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2633 wlock_acquire(rtld_bind_lock, &mlockstate); 2634 lockstate = &mlockstate; 2635 } 2636 GDB_STATE(RT_ADD,NULL); 2637 2638 old_obj_tail = obj_tail; 2639 obj = NULL; 2640 if (name == NULL && fd == -1) { 2641 obj = obj_main; 2642 obj->refcount++; 2643 } else { 2644 obj = load_object(name, fd, refobj, lo_flags); 2645 } 2646 2647 if (obj) { 2648 obj->dl_refcount++; 2649 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2650 objlist_push_tail(&list_global, obj); 2651 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2652 assert(*old_obj_tail == obj); 2653 result = load_needed_objects(obj, 2654 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2655 init_dag(obj); 2656 ref_dag(obj); 2657 if (result != -1) 2658 result = rtld_verify_versions(&obj->dagmembers); 2659 if (result != -1 && ld_tracing) 2660 goto trace; 2661 if (result == -1 || relocate_object_dag(obj, 2662 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2663 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2664 lockstate) == -1) { 2665 dlopen_cleanup(obj); 2666 obj = NULL; 2667 } else if (lo_flags & RTLD_LO_EARLY) { 2668 /* 2669 * Do not call the init functions for early loaded 2670 * filtees. The image is still not initialized enough 2671 * for them to work. 2672 * 2673 * Our object is found by the global object list and 2674 * will be ordered among all init calls done right 2675 * before transferring control to main. 2676 */ 2677 } else { 2678 /* Make list of init functions to call. */ 2679 initlist_add_objects(obj, &obj->next, &initlist); 2680 } 2681 } else { 2682 2683 /* 2684 * Bump the reference counts for objects on this DAG. If 2685 * this is the first dlopen() call for the object that was 2686 * already loaded as a dependency, initialize the dag 2687 * starting at it. 2688 */ 2689 init_dag(obj); 2690 ref_dag(obj); 2691 2692 if ((lo_flags & RTLD_LO_TRACE) != 0) 2693 goto trace; 2694 } 2695 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2696 obj->z_nodelete) && !obj->ref_nodel) { 2697 dbg("obj %s nodelete", obj->path); 2698 ref_dag(obj); 2699 obj->z_nodelete = obj->ref_nodel = true; 2700 } 2701 } 2702 2703 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2704 name); 2705 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2706 2707 if (!(lo_flags & RTLD_LO_EARLY)) { 2708 map_stacks_exec(lockstate); 2709 } 2710 2711 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2712 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2713 lockstate) == -1) { 2714 objlist_clear(&initlist); 2715 dlopen_cleanup(obj); 2716 if (lockstate == &mlockstate) 2717 lock_release(rtld_bind_lock, lockstate); 2718 return (NULL); 2719 } 2720 2721 if (!(lo_flags & RTLD_LO_EARLY)) { 2722 /* Call the init functions. */ 2723 objlist_call_init(&initlist, lockstate); 2724 } 2725 objlist_clear(&initlist); 2726 if (lockstate == &mlockstate) 2727 lock_release(rtld_bind_lock, lockstate); 2728 return obj; 2729 trace: 2730 trace_loaded_objects(obj); 2731 if (lockstate == &mlockstate) 2732 lock_release(rtld_bind_lock, lockstate); 2733 exit(0); 2734 } 2735 2736 static void * 2737 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2738 int flags) 2739 { 2740 DoneList donelist; 2741 const Obj_Entry *obj, *defobj; 2742 const Elf_Sym *def; 2743 SymLook req; 2744 RtldLockState lockstate; 2745 #ifndef __ia64__ 2746 tls_index ti; 2747 #endif 2748 int res; 2749 2750 def = NULL; 2751 defobj = NULL; 2752 symlook_init(&req, name); 2753 req.ventry = ve; 2754 req.flags = flags | SYMLOOK_IN_PLT; 2755 req.lockstate = &lockstate; 2756 2757 rlock_acquire(rtld_bind_lock, &lockstate); 2758 if (sigsetjmp(lockstate.env, 0) != 0) 2759 lock_upgrade(rtld_bind_lock, &lockstate); 2760 if (handle == NULL || handle == RTLD_NEXT || 2761 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2762 2763 if ((obj = obj_from_addr(retaddr)) == NULL) { 2764 _rtld_error("Cannot determine caller's shared object"); 2765 lock_release(rtld_bind_lock, &lockstate); 2766 return NULL; 2767 } 2768 if (handle == NULL) { /* Just the caller's shared object. */ 2769 res = symlook_obj(&req, obj); 2770 if (res == 0) { 2771 def = req.sym_out; 2772 defobj = req.defobj_out; 2773 } 2774 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2775 handle == RTLD_SELF) { /* ... caller included */ 2776 if (handle == RTLD_NEXT) 2777 obj = obj->next; 2778 for (; obj != NULL; obj = obj->next) { 2779 res = symlook_obj(&req, obj); 2780 if (res == 0) { 2781 if (def == NULL || 2782 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2783 def = req.sym_out; 2784 defobj = req.defobj_out; 2785 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2786 break; 2787 } 2788 } 2789 } 2790 /* 2791 * Search the dynamic linker itself, and possibly resolve the 2792 * symbol from there. This is how the application links to 2793 * dynamic linker services such as dlopen. 2794 */ 2795 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2796 res = symlook_obj(&req, &obj_rtld); 2797 if (res == 0) { 2798 def = req.sym_out; 2799 defobj = req.defobj_out; 2800 } 2801 } 2802 } else { 2803 assert(handle == RTLD_DEFAULT); 2804 res = symlook_default(&req, obj); 2805 if (res == 0) { 2806 defobj = req.defobj_out; 2807 def = req.sym_out; 2808 } 2809 } 2810 } else { 2811 if ((obj = dlcheck(handle)) == NULL) { 2812 lock_release(rtld_bind_lock, &lockstate); 2813 return NULL; 2814 } 2815 2816 donelist_init(&donelist); 2817 if (obj->mainprog) { 2818 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2819 res = symlook_global(&req, &donelist); 2820 if (res == 0) { 2821 def = req.sym_out; 2822 defobj = req.defobj_out; 2823 } 2824 /* 2825 * Search the dynamic linker itself, and possibly resolve the 2826 * symbol from there. This is how the application links to 2827 * dynamic linker services such as dlopen. 2828 */ 2829 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2830 res = symlook_obj(&req, &obj_rtld); 2831 if (res == 0) { 2832 def = req.sym_out; 2833 defobj = req.defobj_out; 2834 } 2835 } 2836 } 2837 else { 2838 /* Search the whole DAG rooted at the given object. */ 2839 res = symlook_list(&req, &obj->dagmembers, &donelist); 2840 if (res == 0) { 2841 def = req.sym_out; 2842 defobj = req.defobj_out; 2843 } 2844 } 2845 } 2846 2847 if (def != NULL) { 2848 lock_release(rtld_bind_lock, &lockstate); 2849 2850 /* 2851 * The value required by the caller is derived from the value 2852 * of the symbol. For the ia64 architecture, we need to 2853 * construct a function descriptor which the caller can use to 2854 * call the function with the right 'gp' value. For other 2855 * architectures and for non-functions, the value is simply 2856 * the relocated value of the symbol. 2857 */ 2858 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2859 return (make_function_pointer(def, defobj)); 2860 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 2861 return (rtld_resolve_ifunc(defobj, def)); 2862 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 2863 #ifdef __ia64__ 2864 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 2865 #else 2866 ti.ti_module = defobj->tlsindex; 2867 ti.ti_offset = def->st_value; 2868 return (__tls_get_addr(&ti)); 2869 #endif 2870 } else 2871 return (defobj->relocbase + def->st_value); 2872 } 2873 2874 _rtld_error("Undefined symbol \"%s\"", name); 2875 lock_release(rtld_bind_lock, &lockstate); 2876 return NULL; 2877 } 2878 2879 void * 2880 dlsym(void *handle, const char *name) 2881 { 2882 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2883 SYMLOOK_DLSYM); 2884 } 2885 2886 dlfunc_t 2887 dlfunc(void *handle, const char *name) 2888 { 2889 union { 2890 void *d; 2891 dlfunc_t f; 2892 } rv; 2893 2894 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2895 SYMLOOK_DLSYM); 2896 return (rv.f); 2897 } 2898 2899 void * 2900 dlvsym(void *handle, const char *name, const char *version) 2901 { 2902 Ver_Entry ventry; 2903 2904 ventry.name = version; 2905 ventry.file = NULL; 2906 ventry.hash = elf_hash(version); 2907 ventry.flags= 0; 2908 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2909 SYMLOOK_DLSYM); 2910 } 2911 2912 int 2913 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2914 { 2915 const Obj_Entry *obj; 2916 RtldLockState lockstate; 2917 2918 rlock_acquire(rtld_bind_lock, &lockstate); 2919 obj = obj_from_addr(addr); 2920 if (obj == NULL) { 2921 _rtld_error("No shared object contains address"); 2922 lock_release(rtld_bind_lock, &lockstate); 2923 return (0); 2924 } 2925 rtld_fill_dl_phdr_info(obj, phdr_info); 2926 lock_release(rtld_bind_lock, &lockstate); 2927 return (1); 2928 } 2929 2930 int 2931 dladdr(const void *addr, Dl_info *info) 2932 { 2933 const Obj_Entry *obj; 2934 const Elf_Sym *def; 2935 void *symbol_addr; 2936 unsigned long symoffset; 2937 RtldLockState lockstate; 2938 2939 rlock_acquire(rtld_bind_lock, &lockstate); 2940 obj = obj_from_addr(addr); 2941 if (obj == NULL) { 2942 _rtld_error("No shared object contains address"); 2943 lock_release(rtld_bind_lock, &lockstate); 2944 return 0; 2945 } 2946 info->dli_fname = obj->path; 2947 info->dli_fbase = obj->mapbase; 2948 info->dli_saddr = (void *)0; 2949 info->dli_sname = NULL; 2950 2951 /* 2952 * Walk the symbol list looking for the symbol whose address is 2953 * closest to the address sent in. 2954 */ 2955 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 2956 def = obj->symtab + symoffset; 2957 2958 /* 2959 * For skip the symbol if st_shndx is either SHN_UNDEF or 2960 * SHN_COMMON. 2961 */ 2962 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2963 continue; 2964 2965 /* 2966 * If the symbol is greater than the specified address, or if it 2967 * is further away from addr than the current nearest symbol, 2968 * then reject it. 2969 */ 2970 symbol_addr = obj->relocbase + def->st_value; 2971 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2972 continue; 2973 2974 /* Update our idea of the nearest symbol. */ 2975 info->dli_sname = obj->strtab + def->st_name; 2976 info->dli_saddr = symbol_addr; 2977 2978 /* Exact match? */ 2979 if (info->dli_saddr == addr) 2980 break; 2981 } 2982 lock_release(rtld_bind_lock, &lockstate); 2983 return 1; 2984 } 2985 2986 int 2987 dlinfo(void *handle, int request, void *p) 2988 { 2989 const Obj_Entry *obj; 2990 RtldLockState lockstate; 2991 int error; 2992 2993 rlock_acquire(rtld_bind_lock, &lockstate); 2994 2995 if (handle == NULL || handle == RTLD_SELF) { 2996 void *retaddr; 2997 2998 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2999 if ((obj = obj_from_addr(retaddr)) == NULL) 3000 _rtld_error("Cannot determine caller's shared object"); 3001 } else 3002 obj = dlcheck(handle); 3003 3004 if (obj == NULL) { 3005 lock_release(rtld_bind_lock, &lockstate); 3006 return (-1); 3007 } 3008 3009 error = 0; 3010 switch (request) { 3011 case RTLD_DI_LINKMAP: 3012 *((struct link_map const **)p) = &obj->linkmap; 3013 break; 3014 case RTLD_DI_ORIGIN: 3015 error = rtld_dirname(obj->path, p); 3016 break; 3017 3018 case RTLD_DI_SERINFOSIZE: 3019 case RTLD_DI_SERINFO: 3020 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3021 break; 3022 3023 default: 3024 _rtld_error("Invalid request %d passed to dlinfo()", request); 3025 error = -1; 3026 } 3027 3028 lock_release(rtld_bind_lock, &lockstate); 3029 3030 return (error); 3031 } 3032 3033 static void 3034 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3035 { 3036 3037 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3038 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 3039 STAILQ_FIRST(&obj->names)->name : obj->path; 3040 phdr_info->dlpi_phdr = obj->phdr; 3041 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3042 phdr_info->dlpi_tls_modid = obj->tlsindex; 3043 phdr_info->dlpi_tls_data = obj->tlsinit; 3044 phdr_info->dlpi_adds = obj_loads; 3045 phdr_info->dlpi_subs = obj_loads - obj_count; 3046 } 3047 3048 int 3049 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3050 { 3051 struct dl_phdr_info phdr_info; 3052 const Obj_Entry *obj; 3053 RtldLockState bind_lockstate, phdr_lockstate; 3054 int error; 3055 3056 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3057 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3058 3059 error = 0; 3060 3061 for (obj = obj_list; obj != NULL; obj = obj->next) { 3062 rtld_fill_dl_phdr_info(obj, &phdr_info); 3063 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3064 break; 3065 3066 } 3067 lock_release(rtld_bind_lock, &bind_lockstate); 3068 lock_release(rtld_phdr_lock, &phdr_lockstate); 3069 3070 return (error); 3071 } 3072 3073 struct fill_search_info_args { 3074 int request; 3075 unsigned int flags; 3076 Dl_serinfo *serinfo; 3077 Dl_serpath *serpath; 3078 char *strspace; 3079 }; 3080 3081 static void * 3082 fill_search_info(const char *dir, size_t dirlen, void *param) 3083 { 3084 struct fill_search_info_args *arg; 3085 3086 arg = param; 3087 3088 if (arg->request == RTLD_DI_SERINFOSIZE) { 3089 arg->serinfo->dls_cnt ++; 3090 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 3091 } else { 3092 struct dl_serpath *s_entry; 3093 3094 s_entry = arg->serpath; 3095 s_entry->dls_name = arg->strspace; 3096 s_entry->dls_flags = arg->flags; 3097 3098 strncpy(arg->strspace, dir, dirlen); 3099 arg->strspace[dirlen] = '\0'; 3100 3101 arg->strspace += dirlen + 1; 3102 arg->serpath++; 3103 } 3104 3105 return (NULL); 3106 } 3107 3108 static int 3109 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3110 { 3111 struct dl_serinfo _info; 3112 struct fill_search_info_args args; 3113 3114 args.request = RTLD_DI_SERINFOSIZE; 3115 args.serinfo = &_info; 3116 3117 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3118 _info.dls_cnt = 0; 3119 3120 path_enumerate(ld_library_path, fill_search_info, &args); 3121 path_enumerate(obj->rpath, fill_search_info, &args); 3122 path_enumerate(gethints(), fill_search_info, &args); 3123 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3124 3125 3126 if (request == RTLD_DI_SERINFOSIZE) { 3127 info->dls_size = _info.dls_size; 3128 info->dls_cnt = _info.dls_cnt; 3129 return (0); 3130 } 3131 3132 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3133 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3134 return (-1); 3135 } 3136 3137 args.request = RTLD_DI_SERINFO; 3138 args.serinfo = info; 3139 args.serpath = &info->dls_serpath[0]; 3140 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3141 3142 args.flags = LA_SER_LIBPATH; 3143 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3144 return (-1); 3145 3146 args.flags = LA_SER_RUNPATH; 3147 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3148 return (-1); 3149 3150 args.flags = LA_SER_CONFIG; 3151 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 3152 return (-1); 3153 3154 args.flags = LA_SER_DEFAULT; 3155 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3156 return (-1); 3157 return (0); 3158 } 3159 3160 static int 3161 rtld_dirname(const char *path, char *bname) 3162 { 3163 const char *endp; 3164 3165 /* Empty or NULL string gets treated as "." */ 3166 if (path == NULL || *path == '\0') { 3167 bname[0] = '.'; 3168 bname[1] = '\0'; 3169 return (0); 3170 } 3171 3172 /* Strip trailing slashes */ 3173 endp = path + strlen(path) - 1; 3174 while (endp > path && *endp == '/') 3175 endp--; 3176 3177 /* Find the start of the dir */ 3178 while (endp > path && *endp != '/') 3179 endp--; 3180 3181 /* Either the dir is "/" or there are no slashes */ 3182 if (endp == path) { 3183 bname[0] = *endp == '/' ? '/' : '.'; 3184 bname[1] = '\0'; 3185 return (0); 3186 } else { 3187 do { 3188 endp--; 3189 } while (endp > path && *endp == '/'); 3190 } 3191 3192 if (endp - path + 2 > PATH_MAX) 3193 { 3194 _rtld_error("Filename is too long: %s", path); 3195 return(-1); 3196 } 3197 3198 strncpy(bname, path, endp - path + 1); 3199 bname[endp - path + 1] = '\0'; 3200 return (0); 3201 } 3202 3203 static int 3204 rtld_dirname_abs(const char *path, char *base) 3205 { 3206 char base_rel[PATH_MAX]; 3207 3208 if (rtld_dirname(path, base) == -1) 3209 return (-1); 3210 if (base[0] == '/') 3211 return (0); 3212 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3213 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3214 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3215 return (-1); 3216 strcpy(base, base_rel); 3217 return (0); 3218 } 3219 3220 static void 3221 linkmap_add(Obj_Entry *obj) 3222 { 3223 struct link_map *l = &obj->linkmap; 3224 struct link_map *prev; 3225 3226 obj->linkmap.l_name = obj->path; 3227 obj->linkmap.l_addr = obj->mapbase; 3228 obj->linkmap.l_ld = obj->dynamic; 3229 #ifdef __mips__ 3230 /* GDB needs load offset on MIPS to use the symbols */ 3231 obj->linkmap.l_offs = obj->relocbase; 3232 #endif 3233 3234 if (r_debug.r_map == NULL) { 3235 r_debug.r_map = l; 3236 return; 3237 } 3238 3239 /* 3240 * Scan to the end of the list, but not past the entry for the 3241 * dynamic linker, which we want to keep at the very end. 3242 */ 3243 for (prev = r_debug.r_map; 3244 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3245 prev = prev->l_next) 3246 ; 3247 3248 /* Link in the new entry. */ 3249 l->l_prev = prev; 3250 l->l_next = prev->l_next; 3251 if (l->l_next != NULL) 3252 l->l_next->l_prev = l; 3253 prev->l_next = l; 3254 } 3255 3256 static void 3257 linkmap_delete(Obj_Entry *obj) 3258 { 3259 struct link_map *l = &obj->linkmap; 3260 3261 if (l->l_prev == NULL) { 3262 if ((r_debug.r_map = l->l_next) != NULL) 3263 l->l_next->l_prev = NULL; 3264 return; 3265 } 3266 3267 if ((l->l_prev->l_next = l->l_next) != NULL) 3268 l->l_next->l_prev = l->l_prev; 3269 } 3270 3271 /* 3272 * Function for the debugger to set a breakpoint on to gain control. 3273 * 3274 * The two parameters allow the debugger to easily find and determine 3275 * what the runtime loader is doing and to whom it is doing it. 3276 * 3277 * When the loadhook trap is hit (r_debug_state, set at program 3278 * initialization), the arguments can be found on the stack: 3279 * 3280 * +8 struct link_map *m 3281 * +4 struct r_debug *rd 3282 * +0 RetAddr 3283 */ 3284 void 3285 r_debug_state(struct r_debug* rd, struct link_map *m) 3286 { 3287 /* 3288 * The following is a hack to force the compiler to emit calls to 3289 * this function, even when optimizing. If the function is empty, 3290 * the compiler is not obliged to emit any code for calls to it, 3291 * even when marked __noinline. However, gdb depends on those 3292 * calls being made. 3293 */ 3294 __asm __volatile("" : : : "memory"); 3295 } 3296 3297 /* 3298 * Get address of the pointer variable in the main program. 3299 * Prefer non-weak symbol over the weak one. 3300 */ 3301 static const void ** 3302 get_program_var_addr(const char *name, RtldLockState *lockstate) 3303 { 3304 SymLook req; 3305 DoneList donelist; 3306 3307 symlook_init(&req, name); 3308 req.lockstate = lockstate; 3309 donelist_init(&donelist); 3310 if (symlook_global(&req, &donelist) != 0) 3311 return (NULL); 3312 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3313 return ((const void **)make_function_pointer(req.sym_out, 3314 req.defobj_out)); 3315 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3316 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3317 else 3318 return ((const void **)(req.defobj_out->relocbase + 3319 req.sym_out->st_value)); 3320 } 3321 3322 /* 3323 * Set a pointer variable in the main program to the given value. This 3324 * is used to set key variables such as "environ" before any of the 3325 * init functions are called. 3326 */ 3327 static void 3328 set_program_var(const char *name, const void *value) 3329 { 3330 const void **addr; 3331 3332 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3333 dbg("\"%s\": *%p <-- %p", name, addr, value); 3334 *addr = value; 3335 } 3336 } 3337 3338 /* 3339 * Search the global objects, including dependencies and main object, 3340 * for the given symbol. 3341 */ 3342 static int 3343 symlook_global(SymLook *req, DoneList *donelist) 3344 { 3345 SymLook req1; 3346 const Objlist_Entry *elm; 3347 int res; 3348 3349 symlook_init_from_req(&req1, req); 3350 3351 /* Search all objects loaded at program start up. */ 3352 if (req->defobj_out == NULL || 3353 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3354 res = symlook_list(&req1, &list_main, donelist); 3355 if (res == 0 && (req->defobj_out == NULL || 3356 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3357 req->sym_out = req1.sym_out; 3358 req->defobj_out = req1.defobj_out; 3359 assert(req->defobj_out != NULL); 3360 } 3361 } 3362 3363 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3364 STAILQ_FOREACH(elm, &list_global, link) { 3365 if (req->defobj_out != NULL && 3366 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3367 break; 3368 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3369 if (res == 0 && (req->defobj_out == NULL || 3370 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3371 req->sym_out = req1.sym_out; 3372 req->defobj_out = req1.defobj_out; 3373 assert(req->defobj_out != NULL); 3374 } 3375 } 3376 3377 return (req->sym_out != NULL ? 0 : ESRCH); 3378 } 3379 3380 /* 3381 * Given a symbol name in a referencing object, find the corresponding 3382 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3383 * no definition was found. Returns a pointer to the Obj_Entry of the 3384 * defining object via the reference parameter DEFOBJ_OUT. 3385 */ 3386 static int 3387 symlook_default(SymLook *req, const Obj_Entry *refobj) 3388 { 3389 DoneList donelist; 3390 const Objlist_Entry *elm; 3391 SymLook req1; 3392 int res; 3393 3394 donelist_init(&donelist); 3395 symlook_init_from_req(&req1, req); 3396 3397 /* Look first in the referencing object if linked symbolically. */ 3398 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3399 res = symlook_obj(&req1, refobj); 3400 if (res == 0) { 3401 req->sym_out = req1.sym_out; 3402 req->defobj_out = req1.defobj_out; 3403 assert(req->defobj_out != NULL); 3404 } 3405 } 3406 3407 symlook_global(req, &donelist); 3408 3409 /* Search all dlopened DAGs containing the referencing object. */ 3410 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3411 if (req->sym_out != NULL && 3412 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3413 break; 3414 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3415 if (res == 0 && (req->sym_out == NULL || 3416 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3417 req->sym_out = req1.sym_out; 3418 req->defobj_out = req1.defobj_out; 3419 assert(req->defobj_out != NULL); 3420 } 3421 } 3422 3423 /* 3424 * Search the dynamic linker itself, and possibly resolve the 3425 * symbol from there. This is how the application links to 3426 * dynamic linker services such as dlopen. 3427 */ 3428 if (req->sym_out == NULL || 3429 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3430 res = symlook_obj(&req1, &obj_rtld); 3431 if (res == 0) { 3432 req->sym_out = req1.sym_out; 3433 req->defobj_out = req1.defobj_out; 3434 assert(req->defobj_out != NULL); 3435 } 3436 } 3437 3438 return (req->sym_out != NULL ? 0 : ESRCH); 3439 } 3440 3441 static int 3442 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3443 { 3444 const Elf_Sym *def; 3445 const Obj_Entry *defobj; 3446 const Objlist_Entry *elm; 3447 SymLook req1; 3448 int res; 3449 3450 def = NULL; 3451 defobj = NULL; 3452 STAILQ_FOREACH(elm, objlist, link) { 3453 if (donelist_check(dlp, elm->obj)) 3454 continue; 3455 symlook_init_from_req(&req1, req); 3456 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3457 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3458 def = req1.sym_out; 3459 defobj = req1.defobj_out; 3460 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3461 break; 3462 } 3463 } 3464 } 3465 if (def != NULL) { 3466 req->sym_out = def; 3467 req->defobj_out = defobj; 3468 return (0); 3469 } 3470 return (ESRCH); 3471 } 3472 3473 /* 3474 * Search the chain of DAGS cointed to by the given Needed_Entry 3475 * for a symbol of the given name. Each DAG is scanned completely 3476 * before advancing to the next one. Returns a pointer to the symbol, 3477 * or NULL if no definition was found. 3478 */ 3479 static int 3480 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3481 { 3482 const Elf_Sym *def; 3483 const Needed_Entry *n; 3484 const Obj_Entry *defobj; 3485 SymLook req1; 3486 int res; 3487 3488 def = NULL; 3489 defobj = NULL; 3490 symlook_init_from_req(&req1, req); 3491 for (n = needed; n != NULL; n = n->next) { 3492 if (n->obj == NULL || 3493 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3494 continue; 3495 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3496 def = req1.sym_out; 3497 defobj = req1.defobj_out; 3498 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3499 break; 3500 } 3501 } 3502 if (def != NULL) { 3503 req->sym_out = def; 3504 req->defobj_out = defobj; 3505 return (0); 3506 } 3507 return (ESRCH); 3508 } 3509 3510 /* 3511 * Search the symbol table of a single shared object for a symbol of 3512 * the given name and version, if requested. Returns a pointer to the 3513 * symbol, or NULL if no definition was found. If the object is 3514 * filter, return filtered symbol from filtee. 3515 * 3516 * The symbol's hash value is passed in for efficiency reasons; that 3517 * eliminates many recomputations of the hash value. 3518 */ 3519 int 3520 symlook_obj(SymLook *req, const Obj_Entry *obj) 3521 { 3522 DoneList donelist; 3523 SymLook req1; 3524 int flags, res, mres; 3525 3526 /* 3527 * If there is at least one valid hash at this point, we prefer to 3528 * use the faster GNU version if available. 3529 */ 3530 if (obj->valid_hash_gnu) 3531 mres = symlook_obj1_gnu(req, obj); 3532 else if (obj->valid_hash_sysv) 3533 mres = symlook_obj1_sysv(req, obj); 3534 else 3535 return (EINVAL); 3536 3537 if (mres == 0) { 3538 if (obj->needed_filtees != NULL) { 3539 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3540 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3541 donelist_init(&donelist); 3542 symlook_init_from_req(&req1, req); 3543 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3544 if (res == 0) { 3545 req->sym_out = req1.sym_out; 3546 req->defobj_out = req1.defobj_out; 3547 } 3548 return (res); 3549 } 3550 if (obj->needed_aux_filtees != NULL) { 3551 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3552 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3553 donelist_init(&donelist); 3554 symlook_init_from_req(&req1, req); 3555 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3556 if (res == 0) { 3557 req->sym_out = req1.sym_out; 3558 req->defobj_out = req1.defobj_out; 3559 return (res); 3560 } 3561 } 3562 } 3563 return (mres); 3564 } 3565 3566 /* Symbol match routine common to both hash functions */ 3567 static bool 3568 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3569 const unsigned long symnum) 3570 { 3571 Elf_Versym verndx; 3572 const Elf_Sym *symp; 3573 const char *strp; 3574 3575 symp = obj->symtab + symnum; 3576 strp = obj->strtab + symp->st_name; 3577 3578 switch (ELF_ST_TYPE(symp->st_info)) { 3579 case STT_FUNC: 3580 case STT_NOTYPE: 3581 case STT_OBJECT: 3582 case STT_COMMON: 3583 case STT_GNU_IFUNC: 3584 if (symp->st_value == 0) 3585 return (false); 3586 /* fallthrough */ 3587 case STT_TLS: 3588 if (symp->st_shndx != SHN_UNDEF) 3589 break; 3590 #ifndef __mips__ 3591 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3592 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3593 break; 3594 /* fallthrough */ 3595 #endif 3596 default: 3597 return (false); 3598 } 3599 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3600 return (false); 3601 3602 if (req->ventry == NULL) { 3603 if (obj->versyms != NULL) { 3604 verndx = VER_NDX(obj->versyms[symnum]); 3605 if (verndx > obj->vernum) { 3606 _rtld_error( 3607 "%s: symbol %s references wrong version %d", 3608 obj->path, obj->strtab + symnum, verndx); 3609 return (false); 3610 } 3611 /* 3612 * If we are not called from dlsym (i.e. this 3613 * is a normal relocation from unversioned 3614 * binary), accept the symbol immediately if 3615 * it happens to have first version after this 3616 * shared object became versioned. Otherwise, 3617 * if symbol is versioned and not hidden, 3618 * remember it. If it is the only symbol with 3619 * this name exported by the shared object, it 3620 * will be returned as a match by the calling 3621 * function. If symbol is global (verndx < 2) 3622 * accept it unconditionally. 3623 */ 3624 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3625 verndx == VER_NDX_GIVEN) { 3626 result->sym_out = symp; 3627 return (true); 3628 } 3629 else if (verndx >= VER_NDX_GIVEN) { 3630 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3631 == 0) { 3632 if (result->vsymp == NULL) 3633 result->vsymp = symp; 3634 result->vcount++; 3635 } 3636 return (false); 3637 } 3638 } 3639 result->sym_out = symp; 3640 return (true); 3641 } 3642 if (obj->versyms == NULL) { 3643 if (object_match_name(obj, req->ventry->name)) { 3644 _rtld_error("%s: object %s should provide version %s " 3645 "for symbol %s", obj_rtld.path, obj->path, 3646 req->ventry->name, obj->strtab + symnum); 3647 return (false); 3648 } 3649 } else { 3650 verndx = VER_NDX(obj->versyms[symnum]); 3651 if (verndx > obj->vernum) { 3652 _rtld_error("%s: symbol %s references wrong version %d", 3653 obj->path, obj->strtab + symnum, verndx); 3654 return (false); 3655 } 3656 if (obj->vertab[verndx].hash != req->ventry->hash || 3657 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3658 /* 3659 * Version does not match. Look if this is a 3660 * global symbol and if it is not hidden. If 3661 * global symbol (verndx < 2) is available, 3662 * use it. Do not return symbol if we are 3663 * called by dlvsym, because dlvsym looks for 3664 * a specific version and default one is not 3665 * what dlvsym wants. 3666 */ 3667 if ((req->flags & SYMLOOK_DLSYM) || 3668 (verndx >= VER_NDX_GIVEN) || 3669 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3670 return (false); 3671 } 3672 } 3673 result->sym_out = symp; 3674 return (true); 3675 } 3676 3677 /* 3678 * Search for symbol using SysV hash function. 3679 * obj->buckets is known not to be NULL at this point; the test for this was 3680 * performed with the obj->valid_hash_sysv assignment. 3681 */ 3682 static int 3683 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 3684 { 3685 unsigned long symnum; 3686 Sym_Match_Result matchres; 3687 3688 matchres.sym_out = NULL; 3689 matchres.vsymp = NULL; 3690 matchres.vcount = 0; 3691 3692 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 3693 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3694 if (symnum >= obj->nchains) 3695 return (ESRCH); /* Bad object */ 3696 3697 if (matched_symbol(req, obj, &matchres, symnum)) { 3698 req->sym_out = matchres.sym_out; 3699 req->defobj_out = obj; 3700 return (0); 3701 } 3702 } 3703 if (matchres.vcount == 1) { 3704 req->sym_out = matchres.vsymp; 3705 req->defobj_out = obj; 3706 return (0); 3707 } 3708 return (ESRCH); 3709 } 3710 3711 /* Search for symbol using GNU hash function */ 3712 static int 3713 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 3714 { 3715 Elf_Addr bloom_word; 3716 const Elf32_Word *hashval; 3717 Elf32_Word bucket; 3718 Sym_Match_Result matchres; 3719 unsigned int h1, h2; 3720 unsigned long symnum; 3721 3722 matchres.sym_out = NULL; 3723 matchres.vsymp = NULL; 3724 matchres.vcount = 0; 3725 3726 /* Pick right bitmask word from Bloom filter array */ 3727 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 3728 obj->maskwords_bm_gnu]; 3729 3730 /* Calculate modulus word size of gnu hash and its derivative */ 3731 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 3732 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 3733 3734 /* Filter out the "definitely not in set" queries */ 3735 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 3736 return (ESRCH); 3737 3738 /* Locate hash chain and corresponding value element*/ 3739 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 3740 if (bucket == 0) 3741 return (ESRCH); 3742 hashval = &obj->chain_zero_gnu[bucket]; 3743 do { 3744 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 3745 symnum = hashval - obj->chain_zero_gnu; 3746 if (matched_symbol(req, obj, &matchres, symnum)) { 3747 req->sym_out = matchres.sym_out; 3748 req->defobj_out = obj; 3749 return (0); 3750 } 3751 } 3752 } while ((*hashval++ & 1) == 0); 3753 if (matchres.vcount == 1) { 3754 req->sym_out = matchres.vsymp; 3755 req->defobj_out = obj; 3756 return (0); 3757 } 3758 return (ESRCH); 3759 } 3760 3761 static void 3762 trace_loaded_objects(Obj_Entry *obj) 3763 { 3764 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3765 int c; 3766 3767 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3768 main_local = ""; 3769 3770 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3771 fmt1 = "\t%o => %p (%x)\n"; 3772 3773 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3774 fmt2 = "\t%o (%x)\n"; 3775 3776 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3777 3778 for (; obj; obj = obj->next) { 3779 Needed_Entry *needed; 3780 char *name, *path; 3781 bool is_lib; 3782 3783 if (list_containers && obj->needed != NULL) 3784 rtld_printf("%s:\n", obj->path); 3785 for (needed = obj->needed; needed; needed = needed->next) { 3786 if (needed->obj != NULL) { 3787 if (needed->obj->traced && !list_containers) 3788 continue; 3789 needed->obj->traced = true; 3790 path = needed->obj->path; 3791 } else 3792 path = "not found"; 3793 3794 name = (char *)obj->strtab + needed->name; 3795 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3796 3797 fmt = is_lib ? fmt1 : fmt2; 3798 while ((c = *fmt++) != '\0') { 3799 switch (c) { 3800 default: 3801 rtld_putchar(c); 3802 continue; 3803 case '\\': 3804 switch (c = *fmt) { 3805 case '\0': 3806 continue; 3807 case 'n': 3808 rtld_putchar('\n'); 3809 break; 3810 case 't': 3811 rtld_putchar('\t'); 3812 break; 3813 } 3814 break; 3815 case '%': 3816 switch (c = *fmt) { 3817 case '\0': 3818 continue; 3819 case '%': 3820 default: 3821 rtld_putchar(c); 3822 break; 3823 case 'A': 3824 rtld_putstr(main_local); 3825 break; 3826 case 'a': 3827 rtld_putstr(obj_main->path); 3828 break; 3829 case 'o': 3830 rtld_putstr(name); 3831 break; 3832 #if 0 3833 case 'm': 3834 rtld_printf("%d", sodp->sod_major); 3835 break; 3836 case 'n': 3837 rtld_printf("%d", sodp->sod_minor); 3838 break; 3839 #endif 3840 case 'p': 3841 rtld_putstr(path); 3842 break; 3843 case 'x': 3844 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 3845 0); 3846 break; 3847 } 3848 break; 3849 } 3850 ++fmt; 3851 } 3852 } 3853 } 3854 } 3855 3856 /* 3857 * Unload a dlopened object and its dependencies from memory and from 3858 * our data structures. It is assumed that the DAG rooted in the 3859 * object has already been unreferenced, and that the object has a 3860 * reference count of 0. 3861 */ 3862 static void 3863 unload_object(Obj_Entry *root) 3864 { 3865 Obj_Entry *obj; 3866 Obj_Entry **linkp; 3867 3868 assert(root->refcount == 0); 3869 3870 /* 3871 * Pass over the DAG removing unreferenced objects from 3872 * appropriate lists. 3873 */ 3874 unlink_object(root); 3875 3876 /* Unmap all objects that are no longer referenced. */ 3877 linkp = &obj_list->next; 3878 while ((obj = *linkp) != NULL) { 3879 if (obj->refcount == 0) { 3880 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3881 obj->path); 3882 dbg("unloading \"%s\"", obj->path); 3883 unload_filtees(root); 3884 munmap(obj->mapbase, obj->mapsize); 3885 linkmap_delete(obj); 3886 *linkp = obj->next; 3887 obj_count--; 3888 obj_free(obj); 3889 } else 3890 linkp = &obj->next; 3891 } 3892 obj_tail = linkp; 3893 } 3894 3895 static void 3896 unlink_object(Obj_Entry *root) 3897 { 3898 Objlist_Entry *elm; 3899 3900 if (root->refcount == 0) { 3901 /* Remove the object from the RTLD_GLOBAL list. */ 3902 objlist_remove(&list_global, root); 3903 3904 /* Remove the object from all objects' DAG lists. */ 3905 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3906 objlist_remove(&elm->obj->dldags, root); 3907 if (elm->obj != root) 3908 unlink_object(elm->obj); 3909 } 3910 } 3911 } 3912 3913 static void 3914 ref_dag(Obj_Entry *root) 3915 { 3916 Objlist_Entry *elm; 3917 3918 assert(root->dag_inited); 3919 STAILQ_FOREACH(elm, &root->dagmembers, link) 3920 elm->obj->refcount++; 3921 } 3922 3923 static void 3924 unref_dag(Obj_Entry *root) 3925 { 3926 Objlist_Entry *elm; 3927 3928 assert(root->dag_inited); 3929 STAILQ_FOREACH(elm, &root->dagmembers, link) 3930 elm->obj->refcount--; 3931 } 3932 3933 /* 3934 * Common code for MD __tls_get_addr(). 3935 */ 3936 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 3937 static void * 3938 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 3939 { 3940 Elf_Addr *newdtv, *dtv; 3941 RtldLockState lockstate; 3942 int to_copy; 3943 3944 dtv = *dtvp; 3945 /* Check dtv generation in case new modules have arrived */ 3946 if (dtv[0] != tls_dtv_generation) { 3947 wlock_acquire(rtld_bind_lock, &lockstate); 3948 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3949 to_copy = dtv[1]; 3950 if (to_copy > tls_max_index) 3951 to_copy = tls_max_index; 3952 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3953 newdtv[0] = tls_dtv_generation; 3954 newdtv[1] = tls_max_index; 3955 free(dtv); 3956 lock_release(rtld_bind_lock, &lockstate); 3957 dtv = *dtvp = newdtv; 3958 } 3959 3960 /* Dynamically allocate module TLS if necessary */ 3961 if (dtv[index + 1] == 0) { 3962 /* Signal safe, wlock will block out signals. */ 3963 wlock_acquire(rtld_bind_lock, &lockstate); 3964 if (!dtv[index + 1]) 3965 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3966 lock_release(rtld_bind_lock, &lockstate); 3967 } 3968 return ((void *)(dtv[index + 1] + offset)); 3969 } 3970 3971 void * 3972 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 3973 { 3974 Elf_Addr *dtv; 3975 3976 dtv = *dtvp; 3977 /* Check dtv generation in case new modules have arrived */ 3978 if (__predict_true(dtv[0] == tls_dtv_generation && 3979 dtv[index + 1] != 0)) 3980 return ((void *)(dtv[index + 1] + offset)); 3981 return (tls_get_addr_slow(dtvp, index, offset)); 3982 } 3983 3984 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 3985 3986 /* 3987 * Allocate Static TLS using the Variant I method. 3988 */ 3989 void * 3990 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3991 { 3992 Obj_Entry *obj; 3993 char *tcb; 3994 Elf_Addr **tls; 3995 Elf_Addr *dtv; 3996 Elf_Addr addr; 3997 int i; 3998 3999 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4000 return (oldtcb); 4001 4002 assert(tcbsize >= TLS_TCB_SIZE); 4003 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4004 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4005 4006 if (oldtcb != NULL) { 4007 memcpy(tls, oldtcb, tls_static_space); 4008 free(oldtcb); 4009 4010 /* Adjust the DTV. */ 4011 dtv = tls[0]; 4012 for (i = 0; i < dtv[1]; i++) { 4013 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4014 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4015 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4016 } 4017 } 4018 } else { 4019 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4020 tls[0] = dtv; 4021 dtv[0] = tls_dtv_generation; 4022 dtv[1] = tls_max_index; 4023 4024 for (obj = objs; obj; obj = obj->next) { 4025 if (obj->tlsoffset > 0) { 4026 addr = (Elf_Addr)tls + obj->tlsoffset; 4027 if (obj->tlsinitsize > 0) 4028 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4029 if (obj->tlssize > obj->tlsinitsize) 4030 memset((void*) (addr + obj->tlsinitsize), 0, 4031 obj->tlssize - obj->tlsinitsize); 4032 dtv[obj->tlsindex + 1] = addr; 4033 } 4034 } 4035 } 4036 4037 return (tcb); 4038 } 4039 4040 void 4041 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4042 { 4043 Elf_Addr *dtv; 4044 Elf_Addr tlsstart, tlsend; 4045 int dtvsize, i; 4046 4047 assert(tcbsize >= TLS_TCB_SIZE); 4048 4049 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4050 tlsend = tlsstart + tls_static_space; 4051 4052 dtv = *(Elf_Addr **)tlsstart; 4053 dtvsize = dtv[1]; 4054 for (i = 0; i < dtvsize; i++) { 4055 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4056 free((void*)dtv[i+2]); 4057 } 4058 } 4059 free(dtv); 4060 free(tcb); 4061 } 4062 4063 #endif 4064 4065 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4066 4067 /* 4068 * Allocate Static TLS using the Variant II method. 4069 */ 4070 void * 4071 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4072 { 4073 Obj_Entry *obj; 4074 size_t size; 4075 char *tls; 4076 Elf_Addr *dtv, *olddtv; 4077 Elf_Addr segbase, oldsegbase, addr; 4078 int i; 4079 4080 size = round(tls_static_space, tcbalign); 4081 4082 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4083 tls = xcalloc(1, size + tcbsize); 4084 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4085 4086 segbase = (Elf_Addr)(tls + size); 4087 ((Elf_Addr*)segbase)[0] = segbase; 4088 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4089 4090 dtv[0] = tls_dtv_generation; 4091 dtv[1] = tls_max_index; 4092 4093 if (oldtls) { 4094 /* 4095 * Copy the static TLS block over whole. 4096 */ 4097 oldsegbase = (Elf_Addr) oldtls; 4098 memcpy((void *)(segbase - tls_static_space), 4099 (const void *)(oldsegbase - tls_static_space), 4100 tls_static_space); 4101 4102 /* 4103 * If any dynamic TLS blocks have been created tls_get_addr(), 4104 * move them over. 4105 */ 4106 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4107 for (i = 0; i < olddtv[1]; i++) { 4108 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4109 dtv[i+2] = olddtv[i+2]; 4110 olddtv[i+2] = 0; 4111 } 4112 } 4113 4114 /* 4115 * We assume that this block was the one we created with 4116 * allocate_initial_tls(). 4117 */ 4118 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4119 } else { 4120 for (obj = objs; obj; obj = obj->next) { 4121 if (obj->tlsoffset) { 4122 addr = segbase - obj->tlsoffset; 4123 memset((void*) (addr + obj->tlsinitsize), 4124 0, obj->tlssize - obj->tlsinitsize); 4125 if (obj->tlsinit) 4126 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4127 dtv[obj->tlsindex + 1] = addr; 4128 } 4129 } 4130 } 4131 4132 return (void*) segbase; 4133 } 4134 4135 void 4136 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4137 { 4138 size_t size; 4139 Elf_Addr* dtv; 4140 int dtvsize, i; 4141 Elf_Addr tlsstart, tlsend; 4142 4143 /* 4144 * Figure out the size of the initial TLS block so that we can 4145 * find stuff which ___tls_get_addr() allocated dynamically. 4146 */ 4147 size = round(tls_static_space, tcbalign); 4148 4149 dtv = ((Elf_Addr**)tls)[1]; 4150 dtvsize = dtv[1]; 4151 tlsend = (Elf_Addr) tls; 4152 tlsstart = tlsend - size; 4153 for (i = 0; i < dtvsize; i++) { 4154 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 4155 free((void*) dtv[i+2]); 4156 } 4157 } 4158 4159 free((void*) tlsstart); 4160 free((void*) dtv); 4161 } 4162 4163 #endif 4164 4165 /* 4166 * Allocate TLS block for module with given index. 4167 */ 4168 void * 4169 allocate_module_tls(int index) 4170 { 4171 Obj_Entry* obj; 4172 char* p; 4173 4174 for (obj = obj_list; obj; obj = obj->next) { 4175 if (obj->tlsindex == index) 4176 break; 4177 } 4178 if (!obj) { 4179 _rtld_error("Can't find module with TLS index %d", index); 4180 die(); 4181 } 4182 4183 p = malloc(obj->tlssize); 4184 if (p == NULL) { 4185 _rtld_error("Cannot allocate TLS block for index %d", index); 4186 die(); 4187 } 4188 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4189 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4190 4191 return p; 4192 } 4193 4194 bool 4195 allocate_tls_offset(Obj_Entry *obj) 4196 { 4197 size_t off; 4198 4199 if (obj->tls_done) 4200 return true; 4201 4202 if (obj->tlssize == 0) { 4203 obj->tls_done = true; 4204 return true; 4205 } 4206 4207 if (obj->tlsindex == 1) 4208 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4209 else 4210 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4211 obj->tlssize, obj->tlsalign); 4212 4213 /* 4214 * If we have already fixed the size of the static TLS block, we 4215 * must stay within that size. When allocating the static TLS, we 4216 * leave a small amount of space spare to be used for dynamically 4217 * loading modules which use static TLS. 4218 */ 4219 if (tls_static_space) { 4220 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4221 return false; 4222 } 4223 4224 tls_last_offset = obj->tlsoffset = off; 4225 tls_last_size = obj->tlssize; 4226 obj->tls_done = true; 4227 4228 return true; 4229 } 4230 4231 void 4232 free_tls_offset(Obj_Entry *obj) 4233 { 4234 4235 /* 4236 * If we were the last thing to allocate out of the static TLS 4237 * block, we give our space back to the 'allocator'. This is a 4238 * simplistic workaround to allow libGL.so.1 to be loaded and 4239 * unloaded multiple times. 4240 */ 4241 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4242 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4243 tls_last_offset -= obj->tlssize; 4244 tls_last_size = 0; 4245 } 4246 } 4247 4248 void * 4249 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4250 { 4251 void *ret; 4252 RtldLockState lockstate; 4253 4254 wlock_acquire(rtld_bind_lock, &lockstate); 4255 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4256 lock_release(rtld_bind_lock, &lockstate); 4257 return (ret); 4258 } 4259 4260 void 4261 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4262 { 4263 RtldLockState lockstate; 4264 4265 wlock_acquire(rtld_bind_lock, &lockstate); 4266 free_tls(tcb, tcbsize, tcbalign); 4267 lock_release(rtld_bind_lock, &lockstate); 4268 } 4269 4270 static void 4271 object_add_name(Obj_Entry *obj, const char *name) 4272 { 4273 Name_Entry *entry; 4274 size_t len; 4275 4276 len = strlen(name); 4277 entry = malloc(sizeof(Name_Entry) + len); 4278 4279 if (entry != NULL) { 4280 strcpy(entry->name, name); 4281 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4282 } 4283 } 4284 4285 static int 4286 object_match_name(const Obj_Entry *obj, const char *name) 4287 { 4288 Name_Entry *entry; 4289 4290 STAILQ_FOREACH(entry, &obj->names, link) { 4291 if (strcmp(name, entry->name) == 0) 4292 return (1); 4293 } 4294 return (0); 4295 } 4296 4297 static Obj_Entry * 4298 locate_dependency(const Obj_Entry *obj, const char *name) 4299 { 4300 const Objlist_Entry *entry; 4301 const Needed_Entry *needed; 4302 4303 STAILQ_FOREACH(entry, &list_main, link) { 4304 if (object_match_name(entry->obj, name)) 4305 return entry->obj; 4306 } 4307 4308 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4309 if (strcmp(obj->strtab + needed->name, name) == 0 || 4310 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4311 /* 4312 * If there is DT_NEEDED for the name we are looking for, 4313 * we are all set. Note that object might not be found if 4314 * dependency was not loaded yet, so the function can 4315 * return NULL here. This is expected and handled 4316 * properly by the caller. 4317 */ 4318 return (needed->obj); 4319 } 4320 } 4321 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4322 obj->path, name); 4323 die(); 4324 } 4325 4326 static int 4327 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4328 const Elf_Vernaux *vna) 4329 { 4330 const Elf_Verdef *vd; 4331 const char *vername; 4332 4333 vername = refobj->strtab + vna->vna_name; 4334 vd = depobj->verdef; 4335 if (vd == NULL) { 4336 _rtld_error("%s: version %s required by %s not defined", 4337 depobj->path, vername, refobj->path); 4338 return (-1); 4339 } 4340 for (;;) { 4341 if (vd->vd_version != VER_DEF_CURRENT) { 4342 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4343 depobj->path, vd->vd_version); 4344 return (-1); 4345 } 4346 if (vna->vna_hash == vd->vd_hash) { 4347 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4348 ((char *)vd + vd->vd_aux); 4349 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4350 return (0); 4351 } 4352 if (vd->vd_next == 0) 4353 break; 4354 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4355 } 4356 if (vna->vna_flags & VER_FLG_WEAK) 4357 return (0); 4358 _rtld_error("%s: version %s required by %s not found", 4359 depobj->path, vername, refobj->path); 4360 return (-1); 4361 } 4362 4363 static int 4364 rtld_verify_object_versions(Obj_Entry *obj) 4365 { 4366 const Elf_Verneed *vn; 4367 const Elf_Verdef *vd; 4368 const Elf_Verdaux *vda; 4369 const Elf_Vernaux *vna; 4370 const Obj_Entry *depobj; 4371 int maxvernum, vernum; 4372 4373 if (obj->ver_checked) 4374 return (0); 4375 obj->ver_checked = true; 4376 4377 maxvernum = 0; 4378 /* 4379 * Walk over defined and required version records and figure out 4380 * max index used by any of them. Do very basic sanity checking 4381 * while there. 4382 */ 4383 vn = obj->verneed; 4384 while (vn != NULL) { 4385 if (vn->vn_version != VER_NEED_CURRENT) { 4386 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4387 obj->path, vn->vn_version); 4388 return (-1); 4389 } 4390 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4391 for (;;) { 4392 vernum = VER_NEED_IDX(vna->vna_other); 4393 if (vernum > maxvernum) 4394 maxvernum = vernum; 4395 if (vna->vna_next == 0) 4396 break; 4397 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4398 } 4399 if (vn->vn_next == 0) 4400 break; 4401 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4402 } 4403 4404 vd = obj->verdef; 4405 while (vd != NULL) { 4406 if (vd->vd_version != VER_DEF_CURRENT) { 4407 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4408 obj->path, vd->vd_version); 4409 return (-1); 4410 } 4411 vernum = VER_DEF_IDX(vd->vd_ndx); 4412 if (vernum > maxvernum) 4413 maxvernum = vernum; 4414 if (vd->vd_next == 0) 4415 break; 4416 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4417 } 4418 4419 if (maxvernum == 0) 4420 return (0); 4421 4422 /* 4423 * Store version information in array indexable by version index. 4424 * Verify that object version requirements are satisfied along the 4425 * way. 4426 */ 4427 obj->vernum = maxvernum + 1; 4428 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4429 4430 vd = obj->verdef; 4431 while (vd != NULL) { 4432 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4433 vernum = VER_DEF_IDX(vd->vd_ndx); 4434 assert(vernum <= maxvernum); 4435 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4436 obj->vertab[vernum].hash = vd->vd_hash; 4437 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4438 obj->vertab[vernum].file = NULL; 4439 obj->vertab[vernum].flags = 0; 4440 } 4441 if (vd->vd_next == 0) 4442 break; 4443 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4444 } 4445 4446 vn = obj->verneed; 4447 while (vn != NULL) { 4448 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4449 if (depobj == NULL) 4450 return (-1); 4451 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4452 for (;;) { 4453 if (check_object_provided_version(obj, depobj, vna)) 4454 return (-1); 4455 vernum = VER_NEED_IDX(vna->vna_other); 4456 assert(vernum <= maxvernum); 4457 obj->vertab[vernum].hash = vna->vna_hash; 4458 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4459 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4460 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4461 VER_INFO_HIDDEN : 0; 4462 if (vna->vna_next == 0) 4463 break; 4464 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4465 } 4466 if (vn->vn_next == 0) 4467 break; 4468 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4469 } 4470 return 0; 4471 } 4472 4473 static int 4474 rtld_verify_versions(const Objlist *objlist) 4475 { 4476 Objlist_Entry *entry; 4477 int rc; 4478 4479 rc = 0; 4480 STAILQ_FOREACH(entry, objlist, link) { 4481 /* 4482 * Skip dummy objects or objects that have their version requirements 4483 * already checked. 4484 */ 4485 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4486 continue; 4487 if (rtld_verify_object_versions(entry->obj) == -1) { 4488 rc = -1; 4489 if (ld_tracing == NULL) 4490 break; 4491 } 4492 } 4493 if (rc == 0 || ld_tracing != NULL) 4494 rc = rtld_verify_object_versions(&obj_rtld); 4495 return rc; 4496 } 4497 4498 const Ver_Entry * 4499 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4500 { 4501 Elf_Versym vernum; 4502 4503 if (obj->vertab) { 4504 vernum = VER_NDX(obj->versyms[symnum]); 4505 if (vernum >= obj->vernum) { 4506 _rtld_error("%s: symbol %s has wrong verneed value %d", 4507 obj->path, obj->strtab + symnum, vernum); 4508 } else if (obj->vertab[vernum].hash != 0) { 4509 return &obj->vertab[vernum]; 4510 } 4511 } 4512 return NULL; 4513 } 4514 4515 int 4516 _rtld_get_stack_prot(void) 4517 { 4518 4519 return (stack_prot); 4520 } 4521 4522 static void 4523 map_stacks_exec(RtldLockState *lockstate) 4524 { 4525 void (*thr_map_stacks_exec)(void); 4526 4527 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4528 return; 4529 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4530 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4531 if (thr_map_stacks_exec != NULL) { 4532 stack_prot |= PROT_EXEC; 4533 thr_map_stacks_exec(); 4534 } 4535 } 4536 4537 void 4538 symlook_init(SymLook *dst, const char *name) 4539 { 4540 4541 bzero(dst, sizeof(*dst)); 4542 dst->name = name; 4543 dst->hash = elf_hash(name); 4544 dst->hash_gnu = gnu_hash(name); 4545 } 4546 4547 static void 4548 symlook_init_from_req(SymLook *dst, const SymLook *src) 4549 { 4550 4551 dst->name = src->name; 4552 dst->hash = src->hash; 4553 dst->hash_gnu = src->hash_gnu; 4554 dst->ventry = src->ventry; 4555 dst->flags = src->flags; 4556 dst->defobj_out = NULL; 4557 dst->sym_out = NULL; 4558 dst->lockstate = src->lockstate; 4559 } 4560 4561 /* 4562 * Overrides for libc_pic-provided functions. 4563 */ 4564 4565 int 4566 __getosreldate(void) 4567 { 4568 size_t len; 4569 int oid[2]; 4570 int error, osrel; 4571 4572 if (osreldate != 0) 4573 return (osreldate); 4574 4575 oid[0] = CTL_KERN; 4576 oid[1] = KERN_OSRELDATE; 4577 osrel = 0; 4578 len = sizeof(osrel); 4579 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4580 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4581 osreldate = osrel; 4582 return (osreldate); 4583 } 4584 4585 void 4586 exit(int status) 4587 { 4588 4589 _exit(status); 4590 } 4591 4592 void (*__cleanup)(void); 4593 int __isthreaded = 0; 4594 int _thread_autoinit_dummy_decl = 1; 4595 4596 /* 4597 * No unresolved symbols for rtld. 4598 */ 4599 void 4600 __pthread_cxa_finalize(struct dl_phdr_info *a) 4601 { 4602 } 4603 4604 void 4605 __stack_chk_fail(void) 4606 { 4607 4608 _rtld_error("stack overflow detected; terminated"); 4609 die(); 4610 } 4611 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4612 4613 void 4614 __chk_fail(void) 4615 { 4616 4617 _rtld_error("buffer overflow detected; terminated"); 4618 die(); 4619 } 4620 4621 const char * 4622 rtld_strerror(int errnum) 4623 { 4624 4625 if (errnum < 0 || errnum >= sys_nerr) 4626 return ("Unknown error"); 4627 return (sys_errlist[errnum]); 4628 } 4629