1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 /* 31 * Dynamic linker for ELF. 32 * 33 * John Polstra <jdp@polstra.com>. 34 */ 35 36 #ifndef __GNUC__ 37 #error "GCC is needed to compile this file" 38 #endif 39 40 #include <sys/param.h> 41 #include <sys/mount.h> 42 #include <sys/mman.h> 43 #include <sys/stat.h> 44 #include <sys/sysctl.h> 45 #include <sys/uio.h> 46 #include <sys/utsname.h> 47 #include <sys/ktrace.h> 48 49 #include <dlfcn.h> 50 #include <err.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <stdarg.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 #include "debug.h" 60 #include "rtld.h" 61 #include "libmap.h" 62 #include "rtld_tls.h" 63 #include "rtld_printf.h" 64 #include "notes.h" 65 66 #ifndef COMPAT_32BIT 67 #define PATH_RTLD "/libexec/ld-elf.so.1" 68 #else 69 #define PATH_RTLD "/libexec/ld-elf32.so.1" 70 #endif 71 72 /* Types. */ 73 typedef void (*func_ptr_type)(); 74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 75 76 /* 77 * Function declarations. 78 */ 79 static const char *basename(const char *); 80 static void die(void) __dead2; 81 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **); 83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *); 84 static void digest_dynamic(Obj_Entry *, int); 85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 86 static Obj_Entry *dlcheck(void *); 87 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 88 int lo_flags, int mode); 89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 90 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 91 static bool donelist_check(DoneList *, const Obj_Entry *); 92 static void errmsg_restore(char *); 93 static char *errmsg_save(void); 94 static void *fill_search_info(const char *, size_t, void *); 95 static char *find_library(const char *, const Obj_Entry *); 96 static const char *gethints(void); 97 static void init_dag(Obj_Entry *); 98 static void init_rtld(caddr_t, Elf_Auxinfo **); 99 static void initlist_add_neededs(Needed_Entry *, Objlist *); 100 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 101 static void linkmap_add(Obj_Entry *); 102 static void linkmap_delete(Obj_Entry *); 103 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 104 static void unload_filtees(Obj_Entry *); 105 static int load_needed_objects(Obj_Entry *, int); 106 static int load_preload_objects(void); 107 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 108 static void map_stacks_exec(RtldLockState *); 109 static Obj_Entry *obj_from_addr(const void *); 110 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 111 static void objlist_call_init(Objlist *, RtldLockState *); 112 static void objlist_clear(Objlist *); 113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 114 static void objlist_init(Objlist *); 115 static void objlist_push_head(Objlist *, Obj_Entry *); 116 static void objlist_push_tail(Objlist *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 120 RtldLockState *); 121 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 122 int flags, RtldLockState *lockstate); 123 static int rtld_dirname(const char *, char *); 124 static int rtld_dirname_abs(const char *, char *); 125 static void *rtld_dlopen(const char *name, int fd, int mode); 126 static void rtld_exit(void); 127 static char *search_library_path(const char *, const char *); 128 static const void **get_program_var_addr(const char *, RtldLockState *); 129 static void set_program_var(const char *, const void *); 130 static int symlook_default(SymLook *, const Obj_Entry *refobj); 131 static int symlook_global(SymLook *, DoneList *); 132 static void symlook_init_from_req(SymLook *, const SymLook *); 133 static int symlook_list(SymLook *, const Objlist *, DoneList *); 134 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 135 static int symlook_obj1(SymLook *, const Obj_Entry *); 136 static void trace_loaded_objects(Obj_Entry *); 137 static void unlink_object(Obj_Entry *); 138 static void unload_object(Obj_Entry *); 139 static void unref_dag(Obj_Entry *); 140 static void ref_dag(Obj_Entry *); 141 static int origin_subst_one(char **, const char *, const char *, 142 const char *, char *); 143 static char *origin_subst(const char *, const char *); 144 static void preinit_main(void); 145 static int rtld_verify_versions(const Objlist *); 146 static int rtld_verify_object_versions(Obj_Entry *); 147 static void object_add_name(Obj_Entry *, const char *); 148 static int object_match_name(const Obj_Entry *, const char *); 149 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 150 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 151 struct dl_phdr_info *phdr_info); 152 153 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 154 155 /* 156 * Data declarations. 157 */ 158 static char *error_message; /* Message for dlerror(), or NULL */ 159 struct r_debug r_debug; /* for GDB; */ 160 static bool libmap_disable; /* Disable libmap */ 161 static bool ld_loadfltr; /* Immediate filters processing */ 162 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 163 static bool trust; /* False for setuid and setgid programs */ 164 static bool dangerous_ld_env; /* True if environment variables have been 165 used to affect the libraries loaded */ 166 static char *ld_bind_now; /* Environment variable for immediate binding */ 167 static char *ld_debug; /* Environment variable for debugging */ 168 static char *ld_library_path; /* Environment variable for search path */ 169 static char *ld_preload; /* Environment variable for libraries to 170 load first */ 171 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 172 static char *ld_tracing; /* Called from ldd to print libs */ 173 static char *ld_utrace; /* Use utrace() to log events. */ 174 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 175 static Obj_Entry **obj_tail; /* Link field of last object in list */ 176 static Obj_Entry *obj_main; /* The main program shared object */ 177 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 178 static unsigned int obj_count; /* Number of objects in obj_list */ 179 static unsigned int obj_loads; /* Number of objects in obj_list */ 180 181 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 182 STAILQ_HEAD_INITIALIZER(list_global); 183 static Objlist list_main = /* Objects loaded at program startup */ 184 STAILQ_HEAD_INITIALIZER(list_main); 185 static Objlist list_fini = /* Objects needing fini() calls */ 186 STAILQ_HEAD_INITIALIZER(list_fini); 187 188 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 189 190 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 191 192 extern Elf_Dyn _DYNAMIC; 193 #pragma weak _DYNAMIC 194 #ifndef RTLD_IS_DYNAMIC 195 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 196 #endif 197 198 int osreldate, pagesize; 199 200 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 201 202 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 203 static int max_stack_flags; 204 205 /* 206 * Global declarations normally provided by crt1. The dynamic linker is 207 * not built with crt1, so we have to provide them ourselves. 208 */ 209 char *__progname; 210 char **environ; 211 212 /* 213 * Used to pass argc, argv to init functions. 214 */ 215 int main_argc; 216 char **main_argv; 217 218 /* 219 * Globals to control TLS allocation. 220 */ 221 size_t tls_last_offset; /* Static TLS offset of last module */ 222 size_t tls_last_size; /* Static TLS size of last module */ 223 size_t tls_static_space; /* Static TLS space allocated */ 224 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 225 int tls_max_index = 1; /* Largest module index allocated */ 226 227 /* 228 * Fill in a DoneList with an allocation large enough to hold all of 229 * the currently-loaded objects. Keep this as a macro since it calls 230 * alloca and we want that to occur within the scope of the caller. 231 */ 232 #define donelist_init(dlp) \ 233 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 234 assert((dlp)->objs != NULL), \ 235 (dlp)->num_alloc = obj_count, \ 236 (dlp)->num_used = 0) 237 238 #define UTRACE_DLOPEN_START 1 239 #define UTRACE_DLOPEN_STOP 2 240 #define UTRACE_DLCLOSE_START 3 241 #define UTRACE_DLCLOSE_STOP 4 242 #define UTRACE_LOAD_OBJECT 5 243 #define UTRACE_UNLOAD_OBJECT 6 244 #define UTRACE_ADD_RUNDEP 7 245 #define UTRACE_PRELOAD_FINISHED 8 246 #define UTRACE_INIT_CALL 9 247 #define UTRACE_FINI_CALL 10 248 249 struct utrace_rtld { 250 char sig[4]; /* 'RTLD' */ 251 int event; 252 void *handle; 253 void *mapbase; /* Used for 'parent' and 'init/fini' */ 254 size_t mapsize; 255 int refcnt; /* Used for 'mode' */ 256 char name[MAXPATHLEN]; 257 }; 258 259 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 260 if (ld_utrace != NULL) \ 261 ld_utrace_log(e, h, mb, ms, r, n); \ 262 } while (0) 263 264 static void 265 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 266 int refcnt, const char *name) 267 { 268 struct utrace_rtld ut; 269 270 ut.sig[0] = 'R'; 271 ut.sig[1] = 'T'; 272 ut.sig[2] = 'L'; 273 ut.sig[3] = 'D'; 274 ut.event = event; 275 ut.handle = handle; 276 ut.mapbase = mapbase; 277 ut.mapsize = mapsize; 278 ut.refcnt = refcnt; 279 bzero(ut.name, sizeof(ut.name)); 280 if (name) 281 strlcpy(ut.name, name, sizeof(ut.name)); 282 utrace(&ut, sizeof(ut)); 283 } 284 285 /* 286 * Main entry point for dynamic linking. The first argument is the 287 * stack pointer. The stack is expected to be laid out as described 288 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 289 * Specifically, the stack pointer points to a word containing 290 * ARGC. Following that in the stack is a null-terminated sequence 291 * of pointers to argument strings. Then comes a null-terminated 292 * sequence of pointers to environment strings. Finally, there is a 293 * sequence of "auxiliary vector" entries. 294 * 295 * The second argument points to a place to store the dynamic linker's 296 * exit procedure pointer and the third to a place to store the main 297 * program's object. 298 * 299 * The return value is the main program's entry point. 300 */ 301 func_ptr_type 302 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 303 { 304 Elf_Auxinfo *aux_info[AT_COUNT]; 305 int i; 306 int argc; 307 char **argv; 308 char **env; 309 Elf_Auxinfo *aux; 310 Elf_Auxinfo *auxp; 311 const char *argv0; 312 Objlist_Entry *entry; 313 Obj_Entry *obj; 314 Obj_Entry **preload_tail; 315 Objlist initlist; 316 RtldLockState lockstate; 317 int mib[2]; 318 size_t len; 319 320 /* 321 * On entry, the dynamic linker itself has not been relocated yet. 322 * Be very careful not to reference any global data until after 323 * init_rtld has returned. It is OK to reference file-scope statics 324 * and string constants, and to call static and global functions. 325 */ 326 327 /* Find the auxiliary vector on the stack. */ 328 argc = *sp++; 329 argv = (char **) sp; 330 sp += argc + 1; /* Skip over arguments and NULL terminator */ 331 env = (char **) sp; 332 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 333 ; 334 aux = (Elf_Auxinfo *) sp; 335 336 /* Digest the auxiliary vector. */ 337 for (i = 0; i < AT_COUNT; i++) 338 aux_info[i] = NULL; 339 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 340 if (auxp->a_type < AT_COUNT) 341 aux_info[auxp->a_type] = auxp; 342 } 343 344 /* Initialize and relocate ourselves. */ 345 assert(aux_info[AT_BASE] != NULL); 346 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 347 348 __progname = obj_rtld.path; 349 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 350 environ = env; 351 main_argc = argc; 352 main_argv = argv; 353 354 if (aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 355 i = aux_info[AT_CANARYLEN]->a_un.a_val; 356 if (i > sizeof(__stack_chk_guard)) 357 i = sizeof(__stack_chk_guard); 358 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 359 } else { 360 mib[0] = CTL_KERN; 361 mib[1] = KERN_ARND; 362 363 len = sizeof(__stack_chk_guard); 364 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 365 len != sizeof(__stack_chk_guard)) { 366 /* If sysctl was unsuccessful, use the "terminator canary". */ 367 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 368 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 369 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 370 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 371 } 372 } 373 374 trust = !issetugid(); 375 376 ld_bind_now = getenv(LD_ "BIND_NOW"); 377 /* 378 * If the process is tainted, then we un-set the dangerous environment 379 * variables. The process will be marked as tainted until setuid(2) 380 * is called. If any child process calls setuid(2) we do not want any 381 * future processes to honor the potentially un-safe variables. 382 */ 383 if (!trust) { 384 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 385 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 386 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 387 unsetenv(LD_ "LOADFLTR")) { 388 _rtld_error("environment corrupt; aborting"); 389 die(); 390 } 391 } 392 ld_debug = getenv(LD_ "DEBUG"); 393 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 394 libmap_override = getenv(LD_ "LIBMAP"); 395 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 396 ld_preload = getenv(LD_ "PRELOAD"); 397 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 398 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 399 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 400 (ld_library_path != NULL) || (ld_preload != NULL) || 401 (ld_elf_hints_path != NULL) || ld_loadfltr; 402 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 403 ld_utrace = getenv(LD_ "UTRACE"); 404 405 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 406 ld_elf_hints_path = _PATH_ELF_HINTS; 407 408 if (ld_debug != NULL && *ld_debug != '\0') 409 debug = 1; 410 dbg("%s is initialized, base address = %p", __progname, 411 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 412 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 413 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 414 415 dbg("initializing thread locks"); 416 lockdflt_init(); 417 418 /* 419 * Load the main program, or process its program header if it is 420 * already loaded. 421 */ 422 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 423 int fd = aux_info[AT_EXECFD]->a_un.a_val; 424 dbg("loading main program"); 425 obj_main = map_object(fd, argv0, NULL); 426 close(fd); 427 if (obj_main == NULL) 428 die(); 429 max_stack_flags = obj->stack_flags; 430 } else { /* Main program already loaded. */ 431 const Elf_Phdr *phdr; 432 int phnum; 433 caddr_t entry; 434 435 dbg("processing main program's program header"); 436 assert(aux_info[AT_PHDR] != NULL); 437 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 438 assert(aux_info[AT_PHNUM] != NULL); 439 phnum = aux_info[AT_PHNUM]->a_un.a_val; 440 assert(aux_info[AT_PHENT] != NULL); 441 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 442 assert(aux_info[AT_ENTRY] != NULL); 443 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 444 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 445 die(); 446 } 447 448 if (aux_info[AT_EXECPATH] != 0) { 449 char *kexecpath; 450 char buf[MAXPATHLEN]; 451 452 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 453 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 454 if (kexecpath[0] == '/') 455 obj_main->path = kexecpath; 456 else if (getcwd(buf, sizeof(buf)) == NULL || 457 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 458 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 459 obj_main->path = xstrdup(argv0); 460 else 461 obj_main->path = xstrdup(buf); 462 } else { 463 dbg("No AT_EXECPATH"); 464 obj_main->path = xstrdup(argv0); 465 } 466 dbg("obj_main path %s", obj_main->path); 467 obj_main->mainprog = true; 468 469 if (aux_info[AT_STACKPROT] != NULL && 470 aux_info[AT_STACKPROT]->a_un.a_val != 0) 471 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 472 473 /* 474 * Get the actual dynamic linker pathname from the executable if 475 * possible. (It should always be possible.) That ensures that 476 * gdb will find the right dynamic linker even if a non-standard 477 * one is being used. 478 */ 479 if (obj_main->interp != NULL && 480 strcmp(obj_main->interp, obj_rtld.path) != 0) { 481 free(obj_rtld.path); 482 obj_rtld.path = xstrdup(obj_main->interp); 483 __progname = obj_rtld.path; 484 } 485 486 digest_dynamic(obj_main, 0); 487 488 linkmap_add(obj_main); 489 linkmap_add(&obj_rtld); 490 491 /* Link the main program into the list of objects. */ 492 *obj_tail = obj_main; 493 obj_tail = &obj_main->next; 494 obj_count++; 495 obj_loads++; 496 497 /* Initialize a fake symbol for resolving undefined weak references. */ 498 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 499 sym_zero.st_shndx = SHN_UNDEF; 500 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 501 502 if (!libmap_disable) 503 libmap_disable = (bool)lm_init(libmap_override); 504 505 dbg("loading LD_PRELOAD libraries"); 506 if (load_preload_objects() == -1) 507 die(); 508 preload_tail = obj_tail; 509 510 dbg("loading needed objects"); 511 if (load_needed_objects(obj_main, 0) == -1) 512 die(); 513 514 /* Make a list of all objects loaded at startup. */ 515 for (obj = obj_list; obj != NULL; obj = obj->next) { 516 objlist_push_tail(&list_main, obj); 517 obj->refcount++; 518 } 519 520 dbg("checking for required versions"); 521 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 522 die(); 523 524 if (ld_tracing) { /* We're done */ 525 trace_loaded_objects(obj_main); 526 exit(0); 527 } 528 529 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 530 dump_relocations(obj_main); 531 exit (0); 532 } 533 534 /* 535 * Processing tls relocations requires having the tls offsets 536 * initialized. Prepare offsets before starting initial 537 * relocation processing. 538 */ 539 dbg("initializing initial thread local storage offsets"); 540 STAILQ_FOREACH(entry, &list_main, link) { 541 /* 542 * Allocate all the initial objects out of the static TLS 543 * block even if they didn't ask for it. 544 */ 545 allocate_tls_offset(entry->obj); 546 } 547 548 if (relocate_objects(obj_main, 549 ld_bind_now != NULL && *ld_bind_now != '\0', 550 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 551 die(); 552 553 dbg("doing copy relocations"); 554 if (do_copy_relocations(obj_main) == -1) 555 die(); 556 557 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 558 dump_relocations(obj_main); 559 exit (0); 560 } 561 562 /* 563 * Setup TLS for main thread. This must be done after the 564 * relocations are processed, since tls initialization section 565 * might be the subject for relocations. 566 */ 567 dbg("initializing initial thread local storage"); 568 allocate_initial_tls(obj_list); 569 570 dbg("initializing key program variables"); 571 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 572 set_program_var("environ", env); 573 set_program_var("__elf_aux_vector", aux); 574 575 /* Make a list of init functions to call. */ 576 objlist_init(&initlist); 577 initlist_add_objects(obj_list, preload_tail, &initlist); 578 579 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 580 581 map_stacks_exec(NULL); 582 583 dbg("resolving ifuncs"); 584 if (resolve_objects_ifunc(obj_main, 585 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 586 NULL) == -1) 587 die(); 588 589 if (!obj_main->crt_no_init) { 590 /* 591 * Make sure we don't call the main program's init and fini 592 * functions for binaries linked with old crt1 which calls 593 * _init itself. 594 */ 595 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 596 obj_main->preinit_array = obj_main->init_array = 597 obj_main->fini_array = (Elf_Addr)NULL; 598 } 599 600 wlock_acquire(rtld_bind_lock, &lockstate); 601 if (obj_main->crt_no_init) 602 preinit_main(); 603 objlist_call_init(&initlist, &lockstate); 604 objlist_clear(&initlist); 605 dbg("loading filtees"); 606 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 607 if (ld_loadfltr || obj->z_loadfltr) 608 load_filtees(obj, 0, &lockstate); 609 } 610 lock_release(rtld_bind_lock, &lockstate); 611 612 dbg("transferring control to program entry point = %p", obj_main->entry); 613 614 /* Return the exit procedure and the program entry point. */ 615 *exit_proc = rtld_exit; 616 *objp = obj_main; 617 return (func_ptr_type) obj_main->entry; 618 } 619 620 void * 621 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 622 { 623 void *ptr; 624 Elf_Addr target; 625 626 ptr = (void *)make_function_pointer(def, obj); 627 target = ((Elf_Addr (*)(void))ptr)(); 628 return ((void *)target); 629 } 630 631 Elf_Addr 632 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 633 { 634 const Elf_Rel *rel; 635 const Elf_Sym *def; 636 const Obj_Entry *defobj; 637 Elf_Addr *where; 638 Elf_Addr target; 639 RtldLockState lockstate; 640 641 rlock_acquire(rtld_bind_lock, &lockstate); 642 if (sigsetjmp(lockstate.env, 0) != 0) 643 lock_upgrade(rtld_bind_lock, &lockstate); 644 if (obj->pltrel) 645 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 646 else 647 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 648 649 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 650 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 651 &lockstate); 652 if (def == NULL) 653 die(); 654 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 655 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 656 else 657 target = (Elf_Addr)(defobj->relocbase + def->st_value); 658 659 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 660 defobj->strtab + def->st_name, basename(obj->path), 661 (void *)target, basename(defobj->path)); 662 663 /* 664 * Write the new contents for the jmpslot. Note that depending on 665 * architecture, the value which we need to return back to the 666 * lazy binding trampoline may or may not be the target 667 * address. The value returned from reloc_jmpslot() is the value 668 * that the trampoline needs. 669 */ 670 target = reloc_jmpslot(where, target, defobj, obj, rel); 671 lock_release(rtld_bind_lock, &lockstate); 672 return target; 673 } 674 675 /* 676 * Error reporting function. Use it like printf. If formats the message 677 * into a buffer, and sets things up so that the next call to dlerror() 678 * will return the message. 679 */ 680 void 681 _rtld_error(const char *fmt, ...) 682 { 683 static char buf[512]; 684 va_list ap; 685 686 va_start(ap, fmt); 687 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 688 error_message = buf; 689 va_end(ap); 690 } 691 692 /* 693 * Return a dynamically-allocated copy of the current error message, if any. 694 */ 695 static char * 696 errmsg_save(void) 697 { 698 return error_message == NULL ? NULL : xstrdup(error_message); 699 } 700 701 /* 702 * Restore the current error message from a copy which was previously saved 703 * by errmsg_save(). The copy is freed. 704 */ 705 static void 706 errmsg_restore(char *saved_msg) 707 { 708 if (saved_msg == NULL) 709 error_message = NULL; 710 else { 711 _rtld_error("%s", saved_msg); 712 free(saved_msg); 713 } 714 } 715 716 static const char * 717 basename(const char *name) 718 { 719 const char *p = strrchr(name, '/'); 720 return p != NULL ? p + 1 : name; 721 } 722 723 static struct utsname uts; 724 725 static int 726 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 727 char *may_free) 728 { 729 const char *p, *p1; 730 char *res1; 731 int subst_len; 732 int kw_len; 733 734 res1 = *res = NULL; 735 p = real; 736 subst_len = kw_len = 0; 737 for (;;) { 738 p1 = strstr(p, kw); 739 if (p1 != NULL) { 740 if (subst_len == 0) { 741 subst_len = strlen(subst); 742 kw_len = strlen(kw); 743 } 744 if (*res == NULL) { 745 *res = xmalloc(PATH_MAX); 746 res1 = *res; 747 } 748 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 749 _rtld_error("Substitution of %s in %s cannot be performed", 750 kw, real); 751 if (may_free != NULL) 752 free(may_free); 753 free(res); 754 return (false); 755 } 756 memcpy(res1, p, p1 - p); 757 res1 += p1 - p; 758 memcpy(res1, subst, subst_len); 759 res1 += subst_len; 760 p = p1 + kw_len; 761 } else { 762 if (*res == NULL) { 763 if (may_free != NULL) 764 *res = may_free; 765 else 766 *res = xstrdup(real); 767 return (true); 768 } 769 *res1 = '\0'; 770 if (may_free != NULL) 771 free(may_free); 772 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 773 free(res); 774 return (false); 775 } 776 return (true); 777 } 778 } 779 } 780 781 static char * 782 origin_subst(const char *real, const char *origin_path) 783 { 784 char *res1, *res2, *res3, *res4; 785 786 if (uts.sysname[0] == '\0') { 787 if (uname(&uts) != 0) { 788 _rtld_error("utsname failed: %d", errno); 789 return (NULL); 790 } 791 } 792 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 793 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 794 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 795 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 796 return (NULL); 797 return (res4); 798 } 799 800 static void 801 die(void) 802 { 803 const char *msg = dlerror(); 804 805 if (msg == NULL) 806 msg = "Fatal error"; 807 rtld_fdputstr(STDERR_FILENO, msg); 808 rtld_fdputchar(STDERR_FILENO, '\n'); 809 _exit(1); 810 } 811 812 /* 813 * Process a shared object's DYNAMIC section, and save the important 814 * information in its Obj_Entry structure. 815 */ 816 static void 817 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 818 const Elf_Dyn **dyn_soname) 819 { 820 const Elf_Dyn *dynp; 821 Needed_Entry **needed_tail = &obj->needed; 822 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 823 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 824 int plttype = DT_REL; 825 826 *dyn_rpath = NULL; 827 *dyn_soname = NULL; 828 829 obj->bind_now = false; 830 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 831 switch (dynp->d_tag) { 832 833 case DT_REL: 834 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 835 break; 836 837 case DT_RELSZ: 838 obj->relsize = dynp->d_un.d_val; 839 break; 840 841 case DT_RELENT: 842 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 843 break; 844 845 case DT_JMPREL: 846 obj->pltrel = (const Elf_Rel *) 847 (obj->relocbase + dynp->d_un.d_ptr); 848 break; 849 850 case DT_PLTRELSZ: 851 obj->pltrelsize = dynp->d_un.d_val; 852 break; 853 854 case DT_RELA: 855 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 856 break; 857 858 case DT_RELASZ: 859 obj->relasize = dynp->d_un.d_val; 860 break; 861 862 case DT_RELAENT: 863 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 864 break; 865 866 case DT_PLTREL: 867 plttype = dynp->d_un.d_val; 868 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 869 break; 870 871 case DT_SYMTAB: 872 obj->symtab = (const Elf_Sym *) 873 (obj->relocbase + dynp->d_un.d_ptr); 874 break; 875 876 case DT_SYMENT: 877 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 878 break; 879 880 case DT_STRTAB: 881 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 882 break; 883 884 case DT_STRSZ: 885 obj->strsize = dynp->d_un.d_val; 886 break; 887 888 case DT_VERNEED: 889 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 890 dynp->d_un.d_val); 891 break; 892 893 case DT_VERNEEDNUM: 894 obj->verneednum = dynp->d_un.d_val; 895 break; 896 897 case DT_VERDEF: 898 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 899 dynp->d_un.d_val); 900 break; 901 902 case DT_VERDEFNUM: 903 obj->verdefnum = dynp->d_un.d_val; 904 break; 905 906 case DT_VERSYM: 907 obj->versyms = (const Elf_Versym *)(obj->relocbase + 908 dynp->d_un.d_val); 909 break; 910 911 case DT_HASH: 912 { 913 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 914 (obj->relocbase + dynp->d_un.d_ptr); 915 obj->nbuckets = hashtab[0]; 916 obj->nchains = hashtab[1]; 917 obj->buckets = hashtab + 2; 918 obj->chains = obj->buckets + obj->nbuckets; 919 } 920 break; 921 922 case DT_NEEDED: 923 if (!obj->rtld) { 924 Needed_Entry *nep = NEW(Needed_Entry); 925 nep->name = dynp->d_un.d_val; 926 nep->obj = NULL; 927 nep->next = NULL; 928 929 *needed_tail = nep; 930 needed_tail = &nep->next; 931 } 932 break; 933 934 case DT_FILTER: 935 if (!obj->rtld) { 936 Needed_Entry *nep = NEW(Needed_Entry); 937 nep->name = dynp->d_un.d_val; 938 nep->obj = NULL; 939 nep->next = NULL; 940 941 *needed_filtees_tail = nep; 942 needed_filtees_tail = &nep->next; 943 } 944 break; 945 946 case DT_AUXILIARY: 947 if (!obj->rtld) { 948 Needed_Entry *nep = NEW(Needed_Entry); 949 nep->name = dynp->d_un.d_val; 950 nep->obj = NULL; 951 nep->next = NULL; 952 953 *needed_aux_filtees_tail = nep; 954 needed_aux_filtees_tail = &nep->next; 955 } 956 break; 957 958 case DT_PLTGOT: 959 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 960 break; 961 962 case DT_TEXTREL: 963 obj->textrel = true; 964 break; 965 966 case DT_SYMBOLIC: 967 obj->symbolic = true; 968 break; 969 970 case DT_RPATH: 971 case DT_RUNPATH: /* XXX: process separately */ 972 /* 973 * We have to wait until later to process this, because we 974 * might not have gotten the address of the string table yet. 975 */ 976 *dyn_rpath = dynp; 977 break; 978 979 case DT_SONAME: 980 *dyn_soname = dynp; 981 break; 982 983 case DT_INIT: 984 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 985 break; 986 987 case DT_PREINIT_ARRAY: 988 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 989 break; 990 991 case DT_PREINIT_ARRAYSZ: 992 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 993 break; 994 995 case DT_INIT_ARRAY: 996 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 997 break; 998 999 case DT_INIT_ARRAYSZ: 1000 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1001 break; 1002 1003 case DT_FINI: 1004 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1005 break; 1006 1007 case DT_FINI_ARRAY: 1008 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1009 break; 1010 1011 case DT_FINI_ARRAYSZ: 1012 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1013 break; 1014 1015 /* 1016 * Don't process DT_DEBUG on MIPS as the dynamic section 1017 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1018 */ 1019 1020 #ifndef __mips__ 1021 case DT_DEBUG: 1022 /* XXX - not implemented yet */ 1023 if (!early) 1024 dbg("Filling in DT_DEBUG entry"); 1025 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1026 break; 1027 #endif 1028 1029 case DT_FLAGS: 1030 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1031 obj->z_origin = true; 1032 if (dynp->d_un.d_val & DF_SYMBOLIC) 1033 obj->symbolic = true; 1034 if (dynp->d_un.d_val & DF_TEXTREL) 1035 obj->textrel = true; 1036 if (dynp->d_un.d_val & DF_BIND_NOW) 1037 obj->bind_now = true; 1038 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1039 ;*/ 1040 break; 1041 #ifdef __mips__ 1042 case DT_MIPS_LOCAL_GOTNO: 1043 obj->local_gotno = dynp->d_un.d_val; 1044 break; 1045 1046 case DT_MIPS_SYMTABNO: 1047 obj->symtabno = dynp->d_un.d_val; 1048 break; 1049 1050 case DT_MIPS_GOTSYM: 1051 obj->gotsym = dynp->d_un.d_val; 1052 break; 1053 1054 case DT_MIPS_RLD_MAP: 1055 #ifdef notyet 1056 if (!early) 1057 dbg("Filling in DT_DEBUG entry"); 1058 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1059 #endif 1060 break; 1061 #endif 1062 1063 case DT_FLAGS_1: 1064 if (dynp->d_un.d_val & DF_1_NOOPEN) 1065 obj->z_noopen = true; 1066 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1067 obj->z_origin = true; 1068 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1069 XXX ;*/ 1070 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1071 obj->bind_now = true; 1072 if (dynp->d_un.d_val & DF_1_NODELETE) 1073 obj->z_nodelete = true; 1074 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1075 obj->z_loadfltr = true; 1076 break; 1077 1078 default: 1079 if (!early) { 1080 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1081 (long)dynp->d_tag); 1082 } 1083 break; 1084 } 1085 } 1086 1087 obj->traced = false; 1088 1089 if (plttype == DT_RELA) { 1090 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1091 obj->pltrel = NULL; 1092 obj->pltrelasize = obj->pltrelsize; 1093 obj->pltrelsize = 0; 1094 } 1095 } 1096 1097 static void 1098 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1099 const Elf_Dyn *dyn_soname) 1100 { 1101 1102 if (obj->z_origin && obj->origin_path == NULL) { 1103 obj->origin_path = xmalloc(PATH_MAX); 1104 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1105 die(); 1106 } 1107 1108 if (dyn_rpath != NULL) { 1109 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1110 if (obj->z_origin) 1111 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1112 } 1113 1114 if (dyn_soname != NULL) 1115 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1116 } 1117 1118 static void 1119 digest_dynamic(Obj_Entry *obj, int early) 1120 { 1121 const Elf_Dyn *dyn_rpath; 1122 const Elf_Dyn *dyn_soname; 1123 1124 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1125 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1126 } 1127 1128 /* 1129 * Process a shared object's program header. This is used only for the 1130 * main program, when the kernel has already loaded the main program 1131 * into memory before calling the dynamic linker. It creates and 1132 * returns an Obj_Entry structure. 1133 */ 1134 static Obj_Entry * 1135 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1136 { 1137 Obj_Entry *obj; 1138 const Elf_Phdr *phlimit = phdr + phnum; 1139 const Elf_Phdr *ph; 1140 Elf_Addr note_start, note_end; 1141 int nsegs = 0; 1142 1143 obj = obj_new(); 1144 for (ph = phdr; ph < phlimit; ph++) { 1145 if (ph->p_type != PT_PHDR) 1146 continue; 1147 1148 obj->phdr = phdr; 1149 obj->phsize = ph->p_memsz; 1150 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1151 break; 1152 } 1153 1154 obj->stack_flags = PF_X | PF_R | PF_W; 1155 1156 for (ph = phdr; ph < phlimit; ph++) { 1157 switch (ph->p_type) { 1158 1159 case PT_INTERP: 1160 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1161 break; 1162 1163 case PT_LOAD: 1164 if (nsegs == 0) { /* First load segment */ 1165 obj->vaddrbase = trunc_page(ph->p_vaddr); 1166 obj->mapbase = obj->vaddrbase + obj->relocbase; 1167 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1168 obj->vaddrbase; 1169 } else { /* Last load segment */ 1170 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1171 obj->vaddrbase; 1172 } 1173 nsegs++; 1174 break; 1175 1176 case PT_DYNAMIC: 1177 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1178 break; 1179 1180 case PT_TLS: 1181 obj->tlsindex = 1; 1182 obj->tlssize = ph->p_memsz; 1183 obj->tlsalign = ph->p_align; 1184 obj->tlsinitsize = ph->p_filesz; 1185 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1186 break; 1187 1188 case PT_GNU_STACK: 1189 obj->stack_flags = ph->p_flags; 1190 break; 1191 1192 case PT_GNU_RELRO: 1193 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1194 obj->relro_size = round_page(ph->p_memsz); 1195 break; 1196 1197 case PT_NOTE: 1198 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1199 note_end = note_start + ph->p_filesz; 1200 digest_notes(obj, note_start, note_end); 1201 break; 1202 } 1203 } 1204 if (nsegs < 1) { 1205 _rtld_error("%s: too few PT_LOAD segments", path); 1206 return NULL; 1207 } 1208 1209 obj->entry = entry; 1210 return obj; 1211 } 1212 1213 void 1214 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1215 { 1216 const Elf_Note *note; 1217 const char *note_name; 1218 uintptr_t p; 1219 1220 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1221 note = (const Elf_Note *)((const char *)(note + 1) + 1222 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1223 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1224 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1225 note->n_descsz != sizeof(int32_t)) 1226 continue; 1227 if (note->n_type != ABI_NOTETYPE && 1228 note->n_type != CRT_NOINIT_NOTETYPE) 1229 continue; 1230 note_name = (const char *)(note + 1); 1231 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1232 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1233 continue; 1234 switch (note->n_type) { 1235 case ABI_NOTETYPE: 1236 /* FreeBSD osrel note */ 1237 p = (uintptr_t)(note + 1); 1238 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1239 obj->osrel = *(const int32_t *)(p); 1240 dbg("note osrel %d", obj->osrel); 1241 break; 1242 case CRT_NOINIT_NOTETYPE: 1243 /* FreeBSD 'crt does not call init' note */ 1244 obj->crt_no_init = true; 1245 dbg("note crt_no_init"); 1246 break; 1247 } 1248 } 1249 } 1250 1251 static Obj_Entry * 1252 dlcheck(void *handle) 1253 { 1254 Obj_Entry *obj; 1255 1256 for (obj = obj_list; obj != NULL; obj = obj->next) 1257 if (obj == (Obj_Entry *) handle) 1258 break; 1259 1260 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1261 _rtld_error("Invalid shared object handle %p", handle); 1262 return NULL; 1263 } 1264 return obj; 1265 } 1266 1267 /* 1268 * If the given object is already in the donelist, return true. Otherwise 1269 * add the object to the list and return false. 1270 */ 1271 static bool 1272 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1273 { 1274 unsigned int i; 1275 1276 for (i = 0; i < dlp->num_used; i++) 1277 if (dlp->objs[i] == obj) 1278 return true; 1279 /* 1280 * Our donelist allocation should always be sufficient. But if 1281 * our threads locking isn't working properly, more shared objects 1282 * could have been loaded since we allocated the list. That should 1283 * never happen, but we'll handle it properly just in case it does. 1284 */ 1285 if (dlp->num_used < dlp->num_alloc) 1286 dlp->objs[dlp->num_used++] = obj; 1287 return false; 1288 } 1289 1290 /* 1291 * Hash function for symbol table lookup. Don't even think about changing 1292 * this. It is specified by the System V ABI. 1293 */ 1294 unsigned long 1295 elf_hash(const char *name) 1296 { 1297 const unsigned char *p = (const unsigned char *) name; 1298 unsigned long h = 0; 1299 unsigned long g; 1300 1301 while (*p != '\0') { 1302 h = (h << 4) + *p++; 1303 if ((g = h & 0xf0000000) != 0) 1304 h ^= g >> 24; 1305 h &= ~g; 1306 } 1307 return h; 1308 } 1309 1310 /* 1311 * Find the library with the given name, and return its full pathname. 1312 * The returned string is dynamically allocated. Generates an error 1313 * message and returns NULL if the library cannot be found. 1314 * 1315 * If the second argument is non-NULL, then it refers to an already- 1316 * loaded shared object, whose library search path will be searched. 1317 * 1318 * The search order is: 1319 * LD_LIBRARY_PATH 1320 * rpath in the referencing file 1321 * ldconfig hints 1322 * /lib:/usr/lib 1323 */ 1324 static char * 1325 find_library(const char *xname, const Obj_Entry *refobj) 1326 { 1327 char *pathname; 1328 char *name; 1329 1330 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1331 if (xname[0] != '/' && !trust) { 1332 _rtld_error("Absolute pathname required for shared object \"%s\"", 1333 xname); 1334 return NULL; 1335 } 1336 if (refobj != NULL && refobj->z_origin) 1337 return origin_subst(xname, refobj->origin_path); 1338 else 1339 return xstrdup(xname); 1340 } 1341 1342 if (libmap_disable || (refobj == NULL) || 1343 (name = lm_find(refobj->path, xname)) == NULL) 1344 name = (char *)xname; 1345 1346 dbg(" Searching for \"%s\"", name); 1347 1348 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1349 (refobj != NULL && 1350 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1351 (pathname = search_library_path(name, gethints())) != NULL || 1352 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1353 return pathname; 1354 1355 if(refobj != NULL && refobj->path != NULL) { 1356 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1357 name, basename(refobj->path)); 1358 } else { 1359 _rtld_error("Shared object \"%s\" not found", name); 1360 } 1361 return NULL; 1362 } 1363 1364 /* 1365 * Given a symbol number in a referencing object, find the corresponding 1366 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1367 * no definition was found. Returns a pointer to the Obj_Entry of the 1368 * defining object via the reference parameter DEFOBJ_OUT. 1369 */ 1370 const Elf_Sym * 1371 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1372 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1373 RtldLockState *lockstate) 1374 { 1375 const Elf_Sym *ref; 1376 const Elf_Sym *def; 1377 const Obj_Entry *defobj; 1378 SymLook req; 1379 const char *name; 1380 int res; 1381 1382 /* 1383 * If we have already found this symbol, get the information from 1384 * the cache. 1385 */ 1386 if (symnum >= refobj->nchains) 1387 return NULL; /* Bad object */ 1388 if (cache != NULL && cache[symnum].sym != NULL) { 1389 *defobj_out = cache[symnum].obj; 1390 return cache[symnum].sym; 1391 } 1392 1393 ref = refobj->symtab + symnum; 1394 name = refobj->strtab + ref->st_name; 1395 def = NULL; 1396 defobj = NULL; 1397 1398 /* 1399 * We don't have to do a full scale lookup if the symbol is local. 1400 * We know it will bind to the instance in this load module; to 1401 * which we already have a pointer (ie ref). By not doing a lookup, 1402 * we not only improve performance, but it also avoids unresolvable 1403 * symbols when local symbols are not in the hash table. This has 1404 * been seen with the ia64 toolchain. 1405 */ 1406 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1407 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1408 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1409 symnum); 1410 } 1411 symlook_init(&req, name); 1412 req.flags = flags; 1413 req.ventry = fetch_ventry(refobj, symnum); 1414 req.lockstate = lockstate; 1415 res = symlook_default(&req, refobj); 1416 if (res == 0) { 1417 def = req.sym_out; 1418 defobj = req.defobj_out; 1419 } 1420 } else { 1421 def = ref; 1422 defobj = refobj; 1423 } 1424 1425 /* 1426 * If we found no definition and the reference is weak, treat the 1427 * symbol as having the value zero. 1428 */ 1429 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1430 def = &sym_zero; 1431 defobj = obj_main; 1432 } 1433 1434 if (def != NULL) { 1435 *defobj_out = defobj; 1436 /* Record the information in the cache to avoid subsequent lookups. */ 1437 if (cache != NULL) { 1438 cache[symnum].sym = def; 1439 cache[symnum].obj = defobj; 1440 } 1441 } else { 1442 if (refobj != &obj_rtld) 1443 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1444 } 1445 return def; 1446 } 1447 1448 /* 1449 * Return the search path from the ldconfig hints file, reading it if 1450 * necessary. Returns NULL if there are problems with the hints file, 1451 * or if the search path there is empty. 1452 */ 1453 static const char * 1454 gethints(void) 1455 { 1456 static char *hints; 1457 1458 if (hints == NULL) { 1459 int fd; 1460 struct elfhints_hdr hdr; 1461 char *p; 1462 1463 /* Keep from trying again in case the hints file is bad. */ 1464 hints = ""; 1465 1466 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1467 return NULL; 1468 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1469 hdr.magic != ELFHINTS_MAGIC || 1470 hdr.version != 1) { 1471 close(fd); 1472 return NULL; 1473 } 1474 p = xmalloc(hdr.dirlistlen + 1); 1475 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1476 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1477 free(p); 1478 close(fd); 1479 return NULL; 1480 } 1481 hints = p; 1482 close(fd); 1483 } 1484 return hints[0] != '\0' ? hints : NULL; 1485 } 1486 1487 static void 1488 init_dag(Obj_Entry *root) 1489 { 1490 const Needed_Entry *needed; 1491 const Objlist_Entry *elm; 1492 DoneList donelist; 1493 1494 if (root->dag_inited) 1495 return; 1496 donelist_init(&donelist); 1497 1498 /* Root object belongs to own DAG. */ 1499 objlist_push_tail(&root->dldags, root); 1500 objlist_push_tail(&root->dagmembers, root); 1501 donelist_check(&donelist, root); 1502 1503 /* 1504 * Add dependencies of root object to DAG in breadth order 1505 * by exploiting the fact that each new object get added 1506 * to the tail of the dagmembers list. 1507 */ 1508 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1509 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1510 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1511 continue; 1512 objlist_push_tail(&needed->obj->dldags, root); 1513 objlist_push_tail(&root->dagmembers, needed->obj); 1514 } 1515 } 1516 root->dag_inited = true; 1517 } 1518 1519 /* 1520 * Initialize the dynamic linker. The argument is the address at which 1521 * the dynamic linker has been mapped into memory. The primary task of 1522 * this function is to relocate the dynamic linker. 1523 */ 1524 static void 1525 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1526 { 1527 Obj_Entry objtmp; /* Temporary rtld object */ 1528 const Elf_Dyn *dyn_rpath; 1529 const Elf_Dyn *dyn_soname; 1530 1531 /* 1532 * Conjure up an Obj_Entry structure for the dynamic linker. 1533 * 1534 * The "path" member can't be initialized yet because string constants 1535 * cannot yet be accessed. Below we will set it correctly. 1536 */ 1537 memset(&objtmp, 0, sizeof(objtmp)); 1538 objtmp.path = NULL; 1539 objtmp.rtld = true; 1540 objtmp.mapbase = mapbase; 1541 #ifdef PIC 1542 objtmp.relocbase = mapbase; 1543 #endif 1544 if (RTLD_IS_DYNAMIC()) { 1545 objtmp.dynamic = rtld_dynamic(&objtmp); 1546 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1547 assert(objtmp.needed == NULL); 1548 #if !defined(__mips__) 1549 /* MIPS has a bogus DT_TEXTREL. */ 1550 assert(!objtmp.textrel); 1551 #endif 1552 1553 /* 1554 * Temporarily put the dynamic linker entry into the object list, so 1555 * that symbols can be found. 1556 */ 1557 1558 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1559 } 1560 1561 /* Initialize the object list. */ 1562 obj_tail = &obj_list; 1563 1564 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1565 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1566 1567 if (aux_info[AT_PAGESZ] != NULL) 1568 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1569 if (aux_info[AT_OSRELDATE] != NULL) 1570 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1571 1572 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1573 1574 /* Replace the path with a dynamically allocated copy. */ 1575 obj_rtld.path = xstrdup(PATH_RTLD); 1576 1577 r_debug.r_brk = r_debug_state; 1578 r_debug.r_state = RT_CONSISTENT; 1579 } 1580 1581 /* 1582 * Add the init functions from a needed object list (and its recursive 1583 * needed objects) to "list". This is not used directly; it is a helper 1584 * function for initlist_add_objects(). The write lock must be held 1585 * when this function is called. 1586 */ 1587 static void 1588 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1589 { 1590 /* Recursively process the successor needed objects. */ 1591 if (needed->next != NULL) 1592 initlist_add_neededs(needed->next, list); 1593 1594 /* Process the current needed object. */ 1595 if (needed->obj != NULL) 1596 initlist_add_objects(needed->obj, &needed->obj->next, list); 1597 } 1598 1599 /* 1600 * Scan all of the DAGs rooted in the range of objects from "obj" to 1601 * "tail" and add their init functions to "list". This recurses over 1602 * the DAGs and ensure the proper init ordering such that each object's 1603 * needed libraries are initialized before the object itself. At the 1604 * same time, this function adds the objects to the global finalization 1605 * list "list_fini" in the opposite order. The write lock must be 1606 * held when this function is called. 1607 */ 1608 static void 1609 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1610 { 1611 1612 if (obj->init_scanned || obj->init_done) 1613 return; 1614 obj->init_scanned = true; 1615 1616 /* Recursively process the successor objects. */ 1617 if (&obj->next != tail) 1618 initlist_add_objects(obj->next, tail, list); 1619 1620 /* Recursively process the needed objects. */ 1621 if (obj->needed != NULL) 1622 initlist_add_neededs(obj->needed, list); 1623 if (obj->needed_filtees != NULL) 1624 initlist_add_neededs(obj->needed_filtees, list); 1625 if (obj->needed_aux_filtees != NULL) 1626 initlist_add_neededs(obj->needed_aux_filtees, list); 1627 1628 /* Add the object to the init list. */ 1629 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1630 obj->init_array != (Elf_Addr)NULL) 1631 objlist_push_tail(list, obj); 1632 1633 /* Add the object to the global fini list in the reverse order. */ 1634 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1635 && !obj->on_fini_list) { 1636 objlist_push_head(&list_fini, obj); 1637 obj->on_fini_list = true; 1638 } 1639 } 1640 1641 #ifndef FPTR_TARGET 1642 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1643 #endif 1644 1645 static void 1646 free_needed_filtees(Needed_Entry *n) 1647 { 1648 Needed_Entry *needed, *needed1; 1649 1650 for (needed = n; needed != NULL; needed = needed->next) { 1651 if (needed->obj != NULL) { 1652 dlclose(needed->obj); 1653 needed->obj = NULL; 1654 } 1655 } 1656 for (needed = n; needed != NULL; needed = needed1) { 1657 needed1 = needed->next; 1658 free(needed); 1659 } 1660 } 1661 1662 static void 1663 unload_filtees(Obj_Entry *obj) 1664 { 1665 1666 free_needed_filtees(obj->needed_filtees); 1667 obj->needed_filtees = NULL; 1668 free_needed_filtees(obj->needed_aux_filtees); 1669 obj->needed_aux_filtees = NULL; 1670 obj->filtees_loaded = false; 1671 } 1672 1673 static void 1674 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags) 1675 { 1676 1677 for (; needed != NULL; needed = needed->next) { 1678 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 1679 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1680 RTLD_LOCAL); 1681 } 1682 } 1683 1684 static void 1685 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1686 { 1687 1688 lock_restart_for_upgrade(lockstate); 1689 if (!obj->filtees_loaded) { 1690 load_filtee1(obj, obj->needed_filtees, flags); 1691 load_filtee1(obj, obj->needed_aux_filtees, flags); 1692 obj->filtees_loaded = true; 1693 } 1694 } 1695 1696 static int 1697 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1698 { 1699 Obj_Entry *obj1; 1700 1701 for (; needed != NULL; needed = needed->next) { 1702 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 1703 flags & ~RTLD_LO_NOLOAD); 1704 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1705 return (-1); 1706 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1707 dbg("obj %s nodelete", obj1->path); 1708 init_dag(obj1); 1709 ref_dag(obj1); 1710 obj1->ref_nodel = true; 1711 } 1712 } 1713 return (0); 1714 } 1715 1716 /* 1717 * Given a shared object, traverse its list of needed objects, and load 1718 * each of them. Returns 0 on success. Generates an error message and 1719 * returns -1 on failure. 1720 */ 1721 static int 1722 load_needed_objects(Obj_Entry *first, int flags) 1723 { 1724 Obj_Entry *obj; 1725 1726 for (obj = first; obj != NULL; obj = obj->next) { 1727 if (process_needed(obj, obj->needed, flags) == -1) 1728 return (-1); 1729 } 1730 return (0); 1731 } 1732 1733 static int 1734 load_preload_objects(void) 1735 { 1736 char *p = ld_preload; 1737 static const char delim[] = " \t:;"; 1738 1739 if (p == NULL) 1740 return 0; 1741 1742 p += strspn(p, delim); 1743 while (*p != '\0') { 1744 size_t len = strcspn(p, delim); 1745 char savech; 1746 1747 savech = p[len]; 1748 p[len] = '\0'; 1749 if (load_object(p, -1, NULL, 0) == NULL) 1750 return -1; /* XXX - cleanup */ 1751 p[len] = savech; 1752 p += len; 1753 p += strspn(p, delim); 1754 } 1755 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1756 return 0; 1757 } 1758 1759 static const char * 1760 printable_path(const char *path) 1761 { 1762 1763 return (path == NULL ? "<unknown>" : path); 1764 } 1765 1766 /* 1767 * Load a shared object into memory, if it is not already loaded. The 1768 * object may be specified by name or by user-supplied file descriptor 1769 * fd_u. In the later case, the fd_u descriptor is not closed, but its 1770 * duplicate is. 1771 * 1772 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1773 * on failure. 1774 */ 1775 static Obj_Entry * 1776 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 1777 { 1778 Obj_Entry *obj; 1779 int fd; 1780 struct stat sb; 1781 char *path; 1782 1783 if (name != NULL) { 1784 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1785 if (object_match_name(obj, name)) 1786 return (obj); 1787 } 1788 1789 path = find_library(name, refobj); 1790 if (path == NULL) 1791 return (NULL); 1792 } else 1793 path = NULL; 1794 1795 /* 1796 * If we didn't find a match by pathname, or the name is not 1797 * supplied, open the file and check again by device and inode. 1798 * This avoids false mismatches caused by multiple links or ".." 1799 * in pathnames. 1800 * 1801 * To avoid a race, we open the file and use fstat() rather than 1802 * using stat(). 1803 */ 1804 fd = -1; 1805 if (fd_u == -1) { 1806 if ((fd = open(path, O_RDONLY)) == -1) { 1807 _rtld_error("Cannot open \"%s\"", path); 1808 free(path); 1809 return (NULL); 1810 } 1811 } else { 1812 fd = dup(fd_u); 1813 if (fd == -1) { 1814 _rtld_error("Cannot dup fd"); 1815 free(path); 1816 return (NULL); 1817 } 1818 } 1819 if (fstat(fd, &sb) == -1) { 1820 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 1821 close(fd); 1822 free(path); 1823 return NULL; 1824 } 1825 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1826 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1827 break; 1828 if (obj != NULL && name != NULL) { 1829 object_add_name(obj, name); 1830 free(path); 1831 close(fd); 1832 return obj; 1833 } 1834 if (flags & RTLD_LO_NOLOAD) { 1835 free(path); 1836 close(fd); 1837 return (NULL); 1838 } 1839 1840 /* First use of this object, so we must map it in */ 1841 obj = do_load_object(fd, name, path, &sb, flags); 1842 if (obj == NULL) 1843 free(path); 1844 close(fd); 1845 1846 return obj; 1847 } 1848 1849 static Obj_Entry * 1850 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1851 int flags) 1852 { 1853 Obj_Entry *obj; 1854 struct statfs fs; 1855 1856 /* 1857 * but first, make sure that environment variables haven't been 1858 * used to circumvent the noexec flag on a filesystem. 1859 */ 1860 if (dangerous_ld_env) { 1861 if (fstatfs(fd, &fs) != 0) { 1862 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 1863 return NULL; 1864 } 1865 if (fs.f_flags & MNT_NOEXEC) { 1866 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1867 return NULL; 1868 } 1869 } 1870 dbg("loading \"%s\"", printable_path(path)); 1871 obj = map_object(fd, printable_path(path), sbp); 1872 if (obj == NULL) 1873 return NULL; 1874 1875 /* 1876 * If DT_SONAME is present in the object, digest_dynamic2 already 1877 * added it to the object names. 1878 */ 1879 if (name != NULL) 1880 object_add_name(obj, name); 1881 obj->path = path; 1882 digest_dynamic(obj, 0); 1883 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1884 RTLD_LO_DLOPEN) { 1885 dbg("refusing to load non-loadable \"%s\"", obj->path); 1886 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1887 munmap(obj->mapbase, obj->mapsize); 1888 obj_free(obj); 1889 return (NULL); 1890 } 1891 1892 *obj_tail = obj; 1893 obj_tail = &obj->next; 1894 obj_count++; 1895 obj_loads++; 1896 linkmap_add(obj); /* for GDB & dlinfo() */ 1897 max_stack_flags |= obj->stack_flags; 1898 1899 dbg(" %p .. %p: %s", obj->mapbase, 1900 obj->mapbase + obj->mapsize - 1, obj->path); 1901 if (obj->textrel) 1902 dbg(" WARNING: %s has impure text", obj->path); 1903 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1904 obj->path); 1905 1906 return obj; 1907 } 1908 1909 static Obj_Entry * 1910 obj_from_addr(const void *addr) 1911 { 1912 Obj_Entry *obj; 1913 1914 for (obj = obj_list; obj != NULL; obj = obj->next) { 1915 if (addr < (void *) obj->mapbase) 1916 continue; 1917 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1918 return obj; 1919 } 1920 return NULL; 1921 } 1922 1923 static void 1924 preinit_main(void) 1925 { 1926 Elf_Addr *preinit_addr; 1927 int index; 1928 1929 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 1930 if (preinit_addr == NULL) 1931 return; 1932 1933 for (index = 0; index < obj_main->preinit_array_num; index++) { 1934 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 1935 dbg("calling preinit function for %s at %p", obj_main->path, 1936 (void *)preinit_addr[index]); 1937 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 1938 0, 0, obj_main->path); 1939 call_init_pointer(obj_main, preinit_addr[index]); 1940 } 1941 } 1942 } 1943 1944 /* 1945 * Call the finalization functions for each of the objects in "list" 1946 * belonging to the DAG of "root" and referenced once. If NULL "root" 1947 * is specified, every finalization function will be called regardless 1948 * of the reference count and the list elements won't be freed. All of 1949 * the objects are expected to have non-NULL fini functions. 1950 */ 1951 static void 1952 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1953 { 1954 Objlist_Entry *elm; 1955 char *saved_msg; 1956 Elf_Addr *fini_addr; 1957 int index; 1958 1959 assert(root == NULL || root->refcount == 1); 1960 1961 /* 1962 * Preserve the current error message since a fini function might 1963 * call into the dynamic linker and overwrite it. 1964 */ 1965 saved_msg = errmsg_save(); 1966 do { 1967 STAILQ_FOREACH(elm, list, link) { 1968 if (root != NULL && (elm->obj->refcount != 1 || 1969 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1970 continue; 1971 /* Remove object from fini list to prevent recursive invocation. */ 1972 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1973 /* 1974 * XXX: If a dlopen() call references an object while the 1975 * fini function is in progress, we might end up trying to 1976 * unload the referenced object in dlclose() or the object 1977 * won't be unloaded although its fini function has been 1978 * called. 1979 */ 1980 lock_release(rtld_bind_lock, lockstate); 1981 1982 /* 1983 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 1984 * When this happens, DT_FINI_ARRAY is processed first. 1985 */ 1986 fini_addr = (Elf_Addr *)elm->obj->fini_array; 1987 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 1988 for (index = elm->obj->fini_array_num - 1; index >= 0; 1989 index--) { 1990 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 1991 dbg("calling fini function for %s at %p", 1992 elm->obj->path, (void *)fini_addr[index]); 1993 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 1994 (void *)fini_addr[index], 0, 0, elm->obj->path); 1995 call_initfini_pointer(elm->obj, fini_addr[index]); 1996 } 1997 } 1998 } 1999 if (elm->obj->fini != (Elf_Addr)NULL) { 2000 dbg("calling fini function for %s at %p", elm->obj->path, 2001 (void *)elm->obj->fini); 2002 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2003 0, 0, elm->obj->path); 2004 call_initfini_pointer(elm->obj, elm->obj->fini); 2005 } 2006 wlock_acquire(rtld_bind_lock, lockstate); 2007 /* No need to free anything if process is going down. */ 2008 if (root != NULL) 2009 free(elm); 2010 /* 2011 * We must restart the list traversal after every fini call 2012 * because a dlclose() call from the fini function or from 2013 * another thread might have modified the reference counts. 2014 */ 2015 break; 2016 } 2017 } while (elm != NULL); 2018 errmsg_restore(saved_msg); 2019 } 2020 2021 /* 2022 * Call the initialization functions for each of the objects in 2023 * "list". All of the objects are expected to have non-NULL init 2024 * functions. 2025 */ 2026 static void 2027 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2028 { 2029 Objlist_Entry *elm; 2030 Obj_Entry *obj; 2031 char *saved_msg; 2032 Elf_Addr *init_addr; 2033 int index; 2034 2035 /* 2036 * Clean init_scanned flag so that objects can be rechecked and 2037 * possibly initialized earlier if any of vectors called below 2038 * cause the change by using dlopen. 2039 */ 2040 for (obj = obj_list; obj != NULL; obj = obj->next) 2041 obj->init_scanned = false; 2042 2043 /* 2044 * Preserve the current error message since an init function might 2045 * call into the dynamic linker and overwrite it. 2046 */ 2047 saved_msg = errmsg_save(); 2048 STAILQ_FOREACH(elm, list, link) { 2049 if (elm->obj->init_done) /* Initialized early. */ 2050 continue; 2051 /* 2052 * Race: other thread might try to use this object before current 2053 * one completes the initilization. Not much can be done here 2054 * without better locking. 2055 */ 2056 elm->obj->init_done = true; 2057 lock_release(rtld_bind_lock, lockstate); 2058 2059 /* 2060 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2061 * When this happens, DT_INIT is processed first. 2062 */ 2063 if (elm->obj->init != (Elf_Addr)NULL) { 2064 dbg("calling init function for %s at %p", elm->obj->path, 2065 (void *)elm->obj->init); 2066 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2067 0, 0, elm->obj->path); 2068 call_initfini_pointer(elm->obj, elm->obj->init); 2069 } 2070 init_addr = (Elf_Addr *)elm->obj->init_array; 2071 if (init_addr != NULL) { 2072 for (index = 0; index < elm->obj->init_array_num; index++) { 2073 if (init_addr[index] != 0 && init_addr[index] != 1) { 2074 dbg("calling init function for %s at %p", elm->obj->path, 2075 (void *)init_addr[index]); 2076 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2077 (void *)init_addr[index], 0, 0, elm->obj->path); 2078 call_init_pointer(elm->obj, init_addr[index]); 2079 } 2080 } 2081 } 2082 wlock_acquire(rtld_bind_lock, lockstate); 2083 } 2084 errmsg_restore(saved_msg); 2085 } 2086 2087 static void 2088 objlist_clear(Objlist *list) 2089 { 2090 Objlist_Entry *elm; 2091 2092 while (!STAILQ_EMPTY(list)) { 2093 elm = STAILQ_FIRST(list); 2094 STAILQ_REMOVE_HEAD(list, link); 2095 free(elm); 2096 } 2097 } 2098 2099 static Objlist_Entry * 2100 objlist_find(Objlist *list, const Obj_Entry *obj) 2101 { 2102 Objlist_Entry *elm; 2103 2104 STAILQ_FOREACH(elm, list, link) 2105 if (elm->obj == obj) 2106 return elm; 2107 return NULL; 2108 } 2109 2110 static void 2111 objlist_init(Objlist *list) 2112 { 2113 STAILQ_INIT(list); 2114 } 2115 2116 static void 2117 objlist_push_head(Objlist *list, Obj_Entry *obj) 2118 { 2119 Objlist_Entry *elm; 2120 2121 elm = NEW(Objlist_Entry); 2122 elm->obj = obj; 2123 STAILQ_INSERT_HEAD(list, elm, link); 2124 } 2125 2126 static void 2127 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2128 { 2129 Objlist_Entry *elm; 2130 2131 elm = NEW(Objlist_Entry); 2132 elm->obj = obj; 2133 STAILQ_INSERT_TAIL(list, elm, link); 2134 } 2135 2136 static void 2137 objlist_remove(Objlist *list, Obj_Entry *obj) 2138 { 2139 Objlist_Entry *elm; 2140 2141 if ((elm = objlist_find(list, obj)) != NULL) { 2142 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2143 free(elm); 2144 } 2145 } 2146 2147 /* 2148 * Relocate newly-loaded shared objects. The argument is a pointer to 2149 * the Obj_Entry for the first such object. All objects from the first 2150 * to the end of the list of objects are relocated. Returns 0 on success, 2151 * or -1 on failure. 2152 */ 2153 static int 2154 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2155 int flags, RtldLockState *lockstate) 2156 { 2157 Obj_Entry *obj; 2158 2159 for (obj = first; obj != NULL; obj = obj->next) { 2160 if (obj->relocated) 2161 continue; 2162 obj->relocated = true; 2163 if (obj != rtldobj) 2164 dbg("relocating \"%s\"", obj->path); 2165 2166 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 2167 obj->symtab == NULL || obj->strtab == NULL) { 2168 _rtld_error("%s: Shared object has no run-time symbol table", 2169 obj->path); 2170 return -1; 2171 } 2172 2173 if (obj->textrel) { 2174 /* There are relocations to the write-protected text segment. */ 2175 if (mprotect(obj->mapbase, obj->textsize, 2176 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2177 _rtld_error("%s: Cannot write-enable text segment: %s", 2178 obj->path, rtld_strerror(errno)); 2179 return -1; 2180 } 2181 } 2182 2183 /* Process the non-PLT relocations. */ 2184 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2185 return -1; 2186 2187 if (obj->textrel) { /* Re-protected the text segment. */ 2188 if (mprotect(obj->mapbase, obj->textsize, 2189 PROT_READ|PROT_EXEC) == -1) { 2190 _rtld_error("%s: Cannot write-protect text segment: %s", 2191 obj->path, rtld_strerror(errno)); 2192 return -1; 2193 } 2194 } 2195 2196 2197 /* Set the special PLT or GOT entries. */ 2198 init_pltgot(obj); 2199 2200 /* Process the PLT relocations. */ 2201 if (reloc_plt(obj) == -1) 2202 return -1; 2203 /* Relocate the jump slots if we are doing immediate binding. */ 2204 if (obj->bind_now || bind_now) 2205 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2206 return -1; 2207 2208 if (obj->relro_size > 0) { 2209 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2210 _rtld_error("%s: Cannot enforce relro protection: %s", 2211 obj->path, rtld_strerror(errno)); 2212 return -1; 2213 } 2214 } 2215 2216 /* 2217 * Set up the magic number and version in the Obj_Entry. These 2218 * were checked in the crt1.o from the original ElfKit, so we 2219 * set them for backward compatibility. 2220 */ 2221 obj->magic = RTLD_MAGIC; 2222 obj->version = RTLD_VERSION; 2223 } 2224 2225 return (0); 2226 } 2227 2228 /* 2229 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2230 * referencing STT_GNU_IFUNC symbols is postponed till the other 2231 * relocations are done. The indirect functions specified as 2232 * ifunc are allowed to call other symbols, so we need to have 2233 * objects relocated before asking for resolution from indirects. 2234 * 2235 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2236 * instead of the usual lazy handling of PLT slots. It is 2237 * consistent with how GNU does it. 2238 */ 2239 static int 2240 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2241 RtldLockState *lockstate) 2242 { 2243 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2244 return (-1); 2245 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2246 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2247 return (-1); 2248 return (0); 2249 } 2250 2251 static int 2252 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2253 RtldLockState *lockstate) 2254 { 2255 Obj_Entry *obj; 2256 2257 for (obj = first; obj != NULL; obj = obj->next) { 2258 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2259 return (-1); 2260 } 2261 return (0); 2262 } 2263 2264 static int 2265 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2266 RtldLockState *lockstate) 2267 { 2268 Objlist_Entry *elm; 2269 2270 STAILQ_FOREACH(elm, list, link) { 2271 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2272 lockstate) == -1) 2273 return (-1); 2274 } 2275 return (0); 2276 } 2277 2278 /* 2279 * Cleanup procedure. It will be called (by the atexit mechanism) just 2280 * before the process exits. 2281 */ 2282 static void 2283 rtld_exit(void) 2284 { 2285 RtldLockState lockstate; 2286 2287 wlock_acquire(rtld_bind_lock, &lockstate); 2288 dbg("rtld_exit()"); 2289 objlist_call_fini(&list_fini, NULL, &lockstate); 2290 /* No need to remove the items from the list, since we are exiting. */ 2291 if (!libmap_disable) 2292 lm_fini(); 2293 lock_release(rtld_bind_lock, &lockstate); 2294 } 2295 2296 static void * 2297 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2298 { 2299 #ifdef COMPAT_32BIT 2300 const char *trans; 2301 #endif 2302 if (path == NULL) 2303 return (NULL); 2304 2305 path += strspn(path, ":;"); 2306 while (*path != '\0') { 2307 size_t len; 2308 char *res; 2309 2310 len = strcspn(path, ":;"); 2311 #ifdef COMPAT_32BIT 2312 trans = lm_findn(NULL, path, len); 2313 if (trans) 2314 res = callback(trans, strlen(trans), arg); 2315 else 2316 #endif 2317 res = callback(path, len, arg); 2318 2319 if (res != NULL) 2320 return (res); 2321 2322 path += len; 2323 path += strspn(path, ":;"); 2324 } 2325 2326 return (NULL); 2327 } 2328 2329 struct try_library_args { 2330 const char *name; 2331 size_t namelen; 2332 char *buffer; 2333 size_t buflen; 2334 }; 2335 2336 static void * 2337 try_library_path(const char *dir, size_t dirlen, void *param) 2338 { 2339 struct try_library_args *arg; 2340 2341 arg = param; 2342 if (*dir == '/' || trust) { 2343 char *pathname; 2344 2345 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2346 return (NULL); 2347 2348 pathname = arg->buffer; 2349 strncpy(pathname, dir, dirlen); 2350 pathname[dirlen] = '/'; 2351 strcpy(pathname + dirlen + 1, arg->name); 2352 2353 dbg(" Trying \"%s\"", pathname); 2354 if (access(pathname, F_OK) == 0) { /* We found it */ 2355 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2356 strcpy(pathname, arg->buffer); 2357 return (pathname); 2358 } 2359 } 2360 return (NULL); 2361 } 2362 2363 static char * 2364 search_library_path(const char *name, const char *path) 2365 { 2366 char *p; 2367 struct try_library_args arg; 2368 2369 if (path == NULL) 2370 return NULL; 2371 2372 arg.name = name; 2373 arg.namelen = strlen(name); 2374 arg.buffer = xmalloc(PATH_MAX); 2375 arg.buflen = PATH_MAX; 2376 2377 p = path_enumerate(path, try_library_path, &arg); 2378 2379 free(arg.buffer); 2380 2381 return (p); 2382 } 2383 2384 int 2385 dlclose(void *handle) 2386 { 2387 Obj_Entry *root; 2388 RtldLockState lockstate; 2389 2390 wlock_acquire(rtld_bind_lock, &lockstate); 2391 root = dlcheck(handle); 2392 if (root == NULL) { 2393 lock_release(rtld_bind_lock, &lockstate); 2394 return -1; 2395 } 2396 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2397 root->path); 2398 2399 /* Unreference the object and its dependencies. */ 2400 root->dl_refcount--; 2401 2402 if (root->refcount == 1) { 2403 /* 2404 * The object will be no longer referenced, so we must unload it. 2405 * First, call the fini functions. 2406 */ 2407 objlist_call_fini(&list_fini, root, &lockstate); 2408 2409 unref_dag(root); 2410 2411 /* Finish cleaning up the newly-unreferenced objects. */ 2412 GDB_STATE(RT_DELETE,&root->linkmap); 2413 unload_object(root); 2414 GDB_STATE(RT_CONSISTENT,NULL); 2415 } else 2416 unref_dag(root); 2417 2418 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2419 lock_release(rtld_bind_lock, &lockstate); 2420 return 0; 2421 } 2422 2423 char * 2424 dlerror(void) 2425 { 2426 char *msg = error_message; 2427 error_message = NULL; 2428 return msg; 2429 } 2430 2431 /* 2432 * This function is deprecated and has no effect. 2433 */ 2434 void 2435 dllockinit(void *context, 2436 void *(*lock_create)(void *context), 2437 void (*rlock_acquire)(void *lock), 2438 void (*wlock_acquire)(void *lock), 2439 void (*lock_release)(void *lock), 2440 void (*lock_destroy)(void *lock), 2441 void (*context_destroy)(void *context)) 2442 { 2443 static void *cur_context; 2444 static void (*cur_context_destroy)(void *); 2445 2446 /* Just destroy the context from the previous call, if necessary. */ 2447 if (cur_context_destroy != NULL) 2448 cur_context_destroy(cur_context); 2449 cur_context = context; 2450 cur_context_destroy = context_destroy; 2451 } 2452 2453 void * 2454 dlopen(const char *name, int mode) 2455 { 2456 2457 return (rtld_dlopen(name, -1, mode)); 2458 } 2459 2460 void * 2461 fdlopen(int fd, int mode) 2462 { 2463 2464 return (rtld_dlopen(NULL, fd, mode)); 2465 } 2466 2467 static void * 2468 rtld_dlopen(const char *name, int fd, int mode) 2469 { 2470 RtldLockState lockstate; 2471 int lo_flags; 2472 2473 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2474 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2475 if (ld_tracing != NULL) { 2476 rlock_acquire(rtld_bind_lock, &lockstate); 2477 if (sigsetjmp(lockstate.env, 0) != 0) 2478 lock_upgrade(rtld_bind_lock, &lockstate); 2479 environ = (char **)*get_program_var_addr("environ", &lockstate); 2480 lock_release(rtld_bind_lock, &lockstate); 2481 } 2482 lo_flags = RTLD_LO_DLOPEN; 2483 if (mode & RTLD_NODELETE) 2484 lo_flags |= RTLD_LO_NODELETE; 2485 if (mode & RTLD_NOLOAD) 2486 lo_flags |= RTLD_LO_NOLOAD; 2487 if (ld_tracing != NULL) 2488 lo_flags |= RTLD_LO_TRACE; 2489 2490 return (dlopen_object(name, fd, obj_main, lo_flags, 2491 mode & (RTLD_MODEMASK | RTLD_GLOBAL))); 2492 } 2493 2494 static void 2495 dlopen_cleanup(Obj_Entry *obj) 2496 { 2497 2498 obj->dl_refcount--; 2499 unref_dag(obj); 2500 if (obj->refcount == 0) 2501 unload_object(obj); 2502 } 2503 2504 static Obj_Entry * 2505 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2506 int mode) 2507 { 2508 Obj_Entry **old_obj_tail; 2509 Obj_Entry *obj; 2510 Objlist initlist; 2511 RtldLockState lockstate; 2512 int result; 2513 2514 objlist_init(&initlist); 2515 2516 wlock_acquire(rtld_bind_lock, &lockstate); 2517 GDB_STATE(RT_ADD,NULL); 2518 2519 old_obj_tail = obj_tail; 2520 obj = NULL; 2521 if (name == NULL && fd == -1) { 2522 obj = obj_main; 2523 obj->refcount++; 2524 } else { 2525 obj = load_object(name, fd, refobj, lo_flags); 2526 } 2527 2528 if (obj) { 2529 obj->dl_refcount++; 2530 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2531 objlist_push_tail(&list_global, obj); 2532 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2533 assert(*old_obj_tail == obj); 2534 result = load_needed_objects(obj, 2535 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2536 init_dag(obj); 2537 ref_dag(obj); 2538 if (result != -1) 2539 result = rtld_verify_versions(&obj->dagmembers); 2540 if (result != -1 && ld_tracing) 2541 goto trace; 2542 if (result == -1 || (relocate_objects(obj, 2543 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2544 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2545 &lockstate)) == -1) { 2546 dlopen_cleanup(obj); 2547 obj = NULL; 2548 } else if (lo_flags & RTLD_LO_EARLY) { 2549 /* 2550 * Do not call the init functions for early loaded 2551 * filtees. The image is still not initialized enough 2552 * for them to work. 2553 * 2554 * Our object is found by the global object list and 2555 * will be ordered among all init calls done right 2556 * before transferring control to main. 2557 */ 2558 } else { 2559 /* Make list of init functions to call. */ 2560 initlist_add_objects(obj, &obj->next, &initlist); 2561 } 2562 } else { 2563 2564 /* 2565 * Bump the reference counts for objects on this DAG. If 2566 * this is the first dlopen() call for the object that was 2567 * already loaded as a dependency, initialize the dag 2568 * starting at it. 2569 */ 2570 init_dag(obj); 2571 ref_dag(obj); 2572 2573 if ((lo_flags & RTLD_LO_TRACE) != 0) 2574 goto trace; 2575 } 2576 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2577 obj->z_nodelete) && !obj->ref_nodel) { 2578 dbg("obj %s nodelete", obj->path); 2579 ref_dag(obj); 2580 obj->z_nodelete = obj->ref_nodel = true; 2581 } 2582 } 2583 2584 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2585 name); 2586 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2587 2588 map_stacks_exec(&lockstate); 2589 2590 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2591 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2592 &lockstate) == -1) { 2593 objlist_clear(&initlist); 2594 dlopen_cleanup(obj); 2595 lock_release(rtld_bind_lock, &lockstate); 2596 return (NULL); 2597 } 2598 2599 if (!(lo_flags & RTLD_LO_EARLY)) { 2600 /* Call the init functions. */ 2601 objlist_call_init(&initlist, &lockstate); 2602 } 2603 objlist_clear(&initlist); 2604 lock_release(rtld_bind_lock, &lockstate); 2605 return obj; 2606 trace: 2607 trace_loaded_objects(obj); 2608 lock_release(rtld_bind_lock, &lockstate); 2609 exit(0); 2610 } 2611 2612 static void * 2613 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2614 int flags) 2615 { 2616 DoneList donelist; 2617 const Obj_Entry *obj, *defobj; 2618 const Elf_Sym *def; 2619 SymLook req; 2620 RtldLockState lockstate; 2621 #ifndef __ia64__ 2622 tls_index ti; 2623 #endif 2624 int res; 2625 2626 def = NULL; 2627 defobj = NULL; 2628 symlook_init(&req, name); 2629 req.ventry = ve; 2630 req.flags = flags | SYMLOOK_IN_PLT; 2631 req.lockstate = &lockstate; 2632 2633 rlock_acquire(rtld_bind_lock, &lockstate); 2634 if (sigsetjmp(lockstate.env, 0) != 0) 2635 lock_upgrade(rtld_bind_lock, &lockstate); 2636 if (handle == NULL || handle == RTLD_NEXT || 2637 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2638 2639 if ((obj = obj_from_addr(retaddr)) == NULL) { 2640 _rtld_error("Cannot determine caller's shared object"); 2641 lock_release(rtld_bind_lock, &lockstate); 2642 return NULL; 2643 } 2644 if (handle == NULL) { /* Just the caller's shared object. */ 2645 res = symlook_obj(&req, obj); 2646 if (res == 0) { 2647 def = req.sym_out; 2648 defobj = req.defobj_out; 2649 } 2650 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2651 handle == RTLD_SELF) { /* ... caller included */ 2652 if (handle == RTLD_NEXT) 2653 obj = obj->next; 2654 for (; obj != NULL; obj = obj->next) { 2655 res = symlook_obj(&req, obj); 2656 if (res == 0) { 2657 if (def == NULL || 2658 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2659 def = req.sym_out; 2660 defobj = req.defobj_out; 2661 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2662 break; 2663 } 2664 } 2665 } 2666 /* 2667 * Search the dynamic linker itself, and possibly resolve the 2668 * symbol from there. This is how the application links to 2669 * dynamic linker services such as dlopen. 2670 */ 2671 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2672 res = symlook_obj(&req, &obj_rtld); 2673 if (res == 0) { 2674 def = req.sym_out; 2675 defobj = req.defobj_out; 2676 } 2677 } 2678 } else { 2679 assert(handle == RTLD_DEFAULT); 2680 res = symlook_default(&req, obj); 2681 if (res == 0) { 2682 defobj = req.defobj_out; 2683 def = req.sym_out; 2684 } 2685 } 2686 } else { 2687 if ((obj = dlcheck(handle)) == NULL) { 2688 lock_release(rtld_bind_lock, &lockstate); 2689 return NULL; 2690 } 2691 2692 donelist_init(&donelist); 2693 if (obj->mainprog) { 2694 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2695 res = symlook_global(&req, &donelist); 2696 if (res == 0) { 2697 def = req.sym_out; 2698 defobj = req.defobj_out; 2699 } 2700 /* 2701 * Search the dynamic linker itself, and possibly resolve the 2702 * symbol from there. This is how the application links to 2703 * dynamic linker services such as dlopen. 2704 */ 2705 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2706 res = symlook_obj(&req, &obj_rtld); 2707 if (res == 0) { 2708 def = req.sym_out; 2709 defobj = req.defobj_out; 2710 } 2711 } 2712 } 2713 else { 2714 /* Search the whole DAG rooted at the given object. */ 2715 res = symlook_list(&req, &obj->dagmembers, &donelist); 2716 if (res == 0) { 2717 def = req.sym_out; 2718 defobj = req.defobj_out; 2719 } 2720 } 2721 } 2722 2723 if (def != NULL) { 2724 lock_release(rtld_bind_lock, &lockstate); 2725 2726 /* 2727 * The value required by the caller is derived from the value 2728 * of the symbol. For the ia64 architecture, we need to 2729 * construct a function descriptor which the caller can use to 2730 * call the function with the right 'gp' value. For other 2731 * architectures and for non-functions, the value is simply 2732 * the relocated value of the symbol. 2733 */ 2734 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2735 return (make_function_pointer(def, defobj)); 2736 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 2737 return (rtld_resolve_ifunc(defobj, def)); 2738 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 2739 #ifdef __ia64__ 2740 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 2741 #else 2742 ti.ti_module = defobj->tlsindex; 2743 ti.ti_offset = def->st_value; 2744 return (__tls_get_addr(&ti)); 2745 #endif 2746 } else 2747 return (defobj->relocbase + def->st_value); 2748 } 2749 2750 _rtld_error("Undefined symbol \"%s\"", name); 2751 lock_release(rtld_bind_lock, &lockstate); 2752 return NULL; 2753 } 2754 2755 void * 2756 dlsym(void *handle, const char *name) 2757 { 2758 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2759 SYMLOOK_DLSYM); 2760 } 2761 2762 dlfunc_t 2763 dlfunc(void *handle, const char *name) 2764 { 2765 union { 2766 void *d; 2767 dlfunc_t f; 2768 } rv; 2769 2770 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2771 SYMLOOK_DLSYM); 2772 return (rv.f); 2773 } 2774 2775 void * 2776 dlvsym(void *handle, const char *name, const char *version) 2777 { 2778 Ver_Entry ventry; 2779 2780 ventry.name = version; 2781 ventry.file = NULL; 2782 ventry.hash = elf_hash(version); 2783 ventry.flags= 0; 2784 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2785 SYMLOOK_DLSYM); 2786 } 2787 2788 int 2789 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2790 { 2791 const Obj_Entry *obj; 2792 RtldLockState lockstate; 2793 2794 rlock_acquire(rtld_bind_lock, &lockstate); 2795 obj = obj_from_addr(addr); 2796 if (obj == NULL) { 2797 _rtld_error("No shared object contains address"); 2798 lock_release(rtld_bind_lock, &lockstate); 2799 return (0); 2800 } 2801 rtld_fill_dl_phdr_info(obj, phdr_info); 2802 lock_release(rtld_bind_lock, &lockstate); 2803 return (1); 2804 } 2805 2806 int 2807 dladdr(const void *addr, Dl_info *info) 2808 { 2809 const Obj_Entry *obj; 2810 const Elf_Sym *def; 2811 void *symbol_addr; 2812 unsigned long symoffset; 2813 RtldLockState lockstate; 2814 2815 rlock_acquire(rtld_bind_lock, &lockstate); 2816 obj = obj_from_addr(addr); 2817 if (obj == NULL) { 2818 _rtld_error("No shared object contains address"); 2819 lock_release(rtld_bind_lock, &lockstate); 2820 return 0; 2821 } 2822 info->dli_fname = obj->path; 2823 info->dli_fbase = obj->mapbase; 2824 info->dli_saddr = (void *)0; 2825 info->dli_sname = NULL; 2826 2827 /* 2828 * Walk the symbol list looking for the symbol whose address is 2829 * closest to the address sent in. 2830 */ 2831 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2832 def = obj->symtab + symoffset; 2833 2834 /* 2835 * For skip the symbol if st_shndx is either SHN_UNDEF or 2836 * SHN_COMMON. 2837 */ 2838 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2839 continue; 2840 2841 /* 2842 * If the symbol is greater than the specified address, or if it 2843 * is further away from addr than the current nearest symbol, 2844 * then reject it. 2845 */ 2846 symbol_addr = obj->relocbase + def->st_value; 2847 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2848 continue; 2849 2850 /* Update our idea of the nearest symbol. */ 2851 info->dli_sname = obj->strtab + def->st_name; 2852 info->dli_saddr = symbol_addr; 2853 2854 /* Exact match? */ 2855 if (info->dli_saddr == addr) 2856 break; 2857 } 2858 lock_release(rtld_bind_lock, &lockstate); 2859 return 1; 2860 } 2861 2862 int 2863 dlinfo(void *handle, int request, void *p) 2864 { 2865 const Obj_Entry *obj; 2866 RtldLockState lockstate; 2867 int error; 2868 2869 rlock_acquire(rtld_bind_lock, &lockstate); 2870 2871 if (handle == NULL || handle == RTLD_SELF) { 2872 void *retaddr; 2873 2874 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2875 if ((obj = obj_from_addr(retaddr)) == NULL) 2876 _rtld_error("Cannot determine caller's shared object"); 2877 } else 2878 obj = dlcheck(handle); 2879 2880 if (obj == NULL) { 2881 lock_release(rtld_bind_lock, &lockstate); 2882 return (-1); 2883 } 2884 2885 error = 0; 2886 switch (request) { 2887 case RTLD_DI_LINKMAP: 2888 *((struct link_map const **)p) = &obj->linkmap; 2889 break; 2890 case RTLD_DI_ORIGIN: 2891 error = rtld_dirname(obj->path, p); 2892 break; 2893 2894 case RTLD_DI_SERINFOSIZE: 2895 case RTLD_DI_SERINFO: 2896 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2897 break; 2898 2899 default: 2900 _rtld_error("Invalid request %d passed to dlinfo()", request); 2901 error = -1; 2902 } 2903 2904 lock_release(rtld_bind_lock, &lockstate); 2905 2906 return (error); 2907 } 2908 2909 static void 2910 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2911 { 2912 2913 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2914 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2915 STAILQ_FIRST(&obj->names)->name : obj->path; 2916 phdr_info->dlpi_phdr = obj->phdr; 2917 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2918 phdr_info->dlpi_tls_modid = obj->tlsindex; 2919 phdr_info->dlpi_tls_data = obj->tlsinit; 2920 phdr_info->dlpi_adds = obj_loads; 2921 phdr_info->dlpi_subs = obj_loads - obj_count; 2922 } 2923 2924 int 2925 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2926 { 2927 struct dl_phdr_info phdr_info; 2928 const Obj_Entry *obj; 2929 RtldLockState bind_lockstate, phdr_lockstate; 2930 int error; 2931 2932 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2933 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2934 2935 error = 0; 2936 2937 for (obj = obj_list; obj != NULL; obj = obj->next) { 2938 rtld_fill_dl_phdr_info(obj, &phdr_info); 2939 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2940 break; 2941 2942 } 2943 lock_release(rtld_bind_lock, &bind_lockstate); 2944 lock_release(rtld_phdr_lock, &phdr_lockstate); 2945 2946 return (error); 2947 } 2948 2949 struct fill_search_info_args { 2950 int request; 2951 unsigned int flags; 2952 Dl_serinfo *serinfo; 2953 Dl_serpath *serpath; 2954 char *strspace; 2955 }; 2956 2957 static void * 2958 fill_search_info(const char *dir, size_t dirlen, void *param) 2959 { 2960 struct fill_search_info_args *arg; 2961 2962 arg = param; 2963 2964 if (arg->request == RTLD_DI_SERINFOSIZE) { 2965 arg->serinfo->dls_cnt ++; 2966 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2967 } else { 2968 struct dl_serpath *s_entry; 2969 2970 s_entry = arg->serpath; 2971 s_entry->dls_name = arg->strspace; 2972 s_entry->dls_flags = arg->flags; 2973 2974 strncpy(arg->strspace, dir, dirlen); 2975 arg->strspace[dirlen] = '\0'; 2976 2977 arg->strspace += dirlen + 1; 2978 arg->serpath++; 2979 } 2980 2981 return (NULL); 2982 } 2983 2984 static int 2985 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2986 { 2987 struct dl_serinfo _info; 2988 struct fill_search_info_args args; 2989 2990 args.request = RTLD_DI_SERINFOSIZE; 2991 args.serinfo = &_info; 2992 2993 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2994 _info.dls_cnt = 0; 2995 2996 path_enumerate(ld_library_path, fill_search_info, &args); 2997 path_enumerate(obj->rpath, fill_search_info, &args); 2998 path_enumerate(gethints(), fill_search_info, &args); 2999 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3000 3001 3002 if (request == RTLD_DI_SERINFOSIZE) { 3003 info->dls_size = _info.dls_size; 3004 info->dls_cnt = _info.dls_cnt; 3005 return (0); 3006 } 3007 3008 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3009 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3010 return (-1); 3011 } 3012 3013 args.request = RTLD_DI_SERINFO; 3014 args.serinfo = info; 3015 args.serpath = &info->dls_serpath[0]; 3016 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3017 3018 args.flags = LA_SER_LIBPATH; 3019 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3020 return (-1); 3021 3022 args.flags = LA_SER_RUNPATH; 3023 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3024 return (-1); 3025 3026 args.flags = LA_SER_CONFIG; 3027 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 3028 return (-1); 3029 3030 args.flags = LA_SER_DEFAULT; 3031 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3032 return (-1); 3033 return (0); 3034 } 3035 3036 static int 3037 rtld_dirname(const char *path, char *bname) 3038 { 3039 const char *endp; 3040 3041 /* Empty or NULL string gets treated as "." */ 3042 if (path == NULL || *path == '\0') { 3043 bname[0] = '.'; 3044 bname[1] = '\0'; 3045 return (0); 3046 } 3047 3048 /* Strip trailing slashes */ 3049 endp = path + strlen(path) - 1; 3050 while (endp > path && *endp == '/') 3051 endp--; 3052 3053 /* Find the start of the dir */ 3054 while (endp > path && *endp != '/') 3055 endp--; 3056 3057 /* Either the dir is "/" or there are no slashes */ 3058 if (endp == path) { 3059 bname[0] = *endp == '/' ? '/' : '.'; 3060 bname[1] = '\0'; 3061 return (0); 3062 } else { 3063 do { 3064 endp--; 3065 } while (endp > path && *endp == '/'); 3066 } 3067 3068 if (endp - path + 2 > PATH_MAX) 3069 { 3070 _rtld_error("Filename is too long: %s", path); 3071 return(-1); 3072 } 3073 3074 strncpy(bname, path, endp - path + 1); 3075 bname[endp - path + 1] = '\0'; 3076 return (0); 3077 } 3078 3079 static int 3080 rtld_dirname_abs(const char *path, char *base) 3081 { 3082 char base_rel[PATH_MAX]; 3083 3084 if (rtld_dirname(path, base) == -1) 3085 return (-1); 3086 if (base[0] == '/') 3087 return (0); 3088 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3089 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3090 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3091 return (-1); 3092 strcpy(base, base_rel); 3093 return (0); 3094 } 3095 3096 static void 3097 linkmap_add(Obj_Entry *obj) 3098 { 3099 struct link_map *l = &obj->linkmap; 3100 struct link_map *prev; 3101 3102 obj->linkmap.l_name = obj->path; 3103 obj->linkmap.l_addr = obj->mapbase; 3104 obj->linkmap.l_ld = obj->dynamic; 3105 #ifdef __mips__ 3106 /* GDB needs load offset on MIPS to use the symbols */ 3107 obj->linkmap.l_offs = obj->relocbase; 3108 #endif 3109 3110 if (r_debug.r_map == NULL) { 3111 r_debug.r_map = l; 3112 return; 3113 } 3114 3115 /* 3116 * Scan to the end of the list, but not past the entry for the 3117 * dynamic linker, which we want to keep at the very end. 3118 */ 3119 for (prev = r_debug.r_map; 3120 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3121 prev = prev->l_next) 3122 ; 3123 3124 /* Link in the new entry. */ 3125 l->l_prev = prev; 3126 l->l_next = prev->l_next; 3127 if (l->l_next != NULL) 3128 l->l_next->l_prev = l; 3129 prev->l_next = l; 3130 } 3131 3132 static void 3133 linkmap_delete(Obj_Entry *obj) 3134 { 3135 struct link_map *l = &obj->linkmap; 3136 3137 if (l->l_prev == NULL) { 3138 if ((r_debug.r_map = l->l_next) != NULL) 3139 l->l_next->l_prev = NULL; 3140 return; 3141 } 3142 3143 if ((l->l_prev->l_next = l->l_next) != NULL) 3144 l->l_next->l_prev = l->l_prev; 3145 } 3146 3147 /* 3148 * Function for the debugger to set a breakpoint on to gain control. 3149 * 3150 * The two parameters allow the debugger to easily find and determine 3151 * what the runtime loader is doing and to whom it is doing it. 3152 * 3153 * When the loadhook trap is hit (r_debug_state, set at program 3154 * initialization), the arguments can be found on the stack: 3155 * 3156 * +8 struct link_map *m 3157 * +4 struct r_debug *rd 3158 * +0 RetAddr 3159 */ 3160 void 3161 r_debug_state(struct r_debug* rd, struct link_map *m) 3162 { 3163 /* 3164 * The following is a hack to force the compiler to emit calls to 3165 * this function, even when optimizing. If the function is empty, 3166 * the compiler is not obliged to emit any code for calls to it, 3167 * even when marked __noinline. However, gdb depends on those 3168 * calls being made. 3169 */ 3170 __asm __volatile("" : : : "memory"); 3171 } 3172 3173 /* 3174 * Get address of the pointer variable in the main program. 3175 * Prefer non-weak symbol over the weak one. 3176 */ 3177 static const void ** 3178 get_program_var_addr(const char *name, RtldLockState *lockstate) 3179 { 3180 SymLook req; 3181 DoneList donelist; 3182 3183 symlook_init(&req, name); 3184 req.lockstate = lockstate; 3185 donelist_init(&donelist); 3186 if (symlook_global(&req, &donelist) != 0) 3187 return (NULL); 3188 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3189 return ((const void **)make_function_pointer(req.sym_out, 3190 req.defobj_out)); 3191 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3192 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3193 else 3194 return ((const void **)(req.defobj_out->relocbase + 3195 req.sym_out->st_value)); 3196 } 3197 3198 /* 3199 * Set a pointer variable in the main program to the given value. This 3200 * is used to set key variables such as "environ" before any of the 3201 * init functions are called. 3202 */ 3203 static void 3204 set_program_var(const char *name, const void *value) 3205 { 3206 const void **addr; 3207 3208 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3209 dbg("\"%s\": *%p <-- %p", name, addr, value); 3210 *addr = value; 3211 } 3212 } 3213 3214 /* 3215 * Search the global objects, including dependencies and main object, 3216 * for the given symbol. 3217 */ 3218 static int 3219 symlook_global(SymLook *req, DoneList *donelist) 3220 { 3221 SymLook req1; 3222 const Objlist_Entry *elm; 3223 int res; 3224 3225 symlook_init_from_req(&req1, req); 3226 3227 /* Search all objects loaded at program start up. */ 3228 if (req->defobj_out == NULL || 3229 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3230 res = symlook_list(&req1, &list_main, donelist); 3231 if (res == 0 && (req->defobj_out == NULL || 3232 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3233 req->sym_out = req1.sym_out; 3234 req->defobj_out = req1.defobj_out; 3235 assert(req->defobj_out != NULL); 3236 } 3237 } 3238 3239 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3240 STAILQ_FOREACH(elm, &list_global, link) { 3241 if (req->defobj_out != NULL && 3242 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3243 break; 3244 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3245 if (res == 0 && (req->defobj_out == NULL || 3246 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3247 req->sym_out = req1.sym_out; 3248 req->defobj_out = req1.defobj_out; 3249 assert(req->defobj_out != NULL); 3250 } 3251 } 3252 3253 return (req->sym_out != NULL ? 0 : ESRCH); 3254 } 3255 3256 /* 3257 * Given a symbol name in a referencing object, find the corresponding 3258 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3259 * no definition was found. Returns a pointer to the Obj_Entry of the 3260 * defining object via the reference parameter DEFOBJ_OUT. 3261 */ 3262 static int 3263 symlook_default(SymLook *req, const Obj_Entry *refobj) 3264 { 3265 DoneList donelist; 3266 const Objlist_Entry *elm; 3267 SymLook req1; 3268 int res; 3269 3270 donelist_init(&donelist); 3271 symlook_init_from_req(&req1, req); 3272 3273 /* Look first in the referencing object if linked symbolically. */ 3274 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3275 res = symlook_obj(&req1, refobj); 3276 if (res == 0) { 3277 req->sym_out = req1.sym_out; 3278 req->defobj_out = req1.defobj_out; 3279 assert(req->defobj_out != NULL); 3280 } 3281 } 3282 3283 symlook_global(req, &donelist); 3284 3285 /* Search all dlopened DAGs containing the referencing object. */ 3286 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3287 if (req->sym_out != NULL && 3288 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3289 break; 3290 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3291 if (res == 0 && (req->sym_out == NULL || 3292 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3293 req->sym_out = req1.sym_out; 3294 req->defobj_out = req1.defobj_out; 3295 assert(req->defobj_out != NULL); 3296 } 3297 } 3298 3299 /* 3300 * Search the dynamic linker itself, and possibly resolve the 3301 * symbol from there. This is how the application links to 3302 * dynamic linker services such as dlopen. 3303 */ 3304 if (req->sym_out == NULL || 3305 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3306 res = symlook_obj(&req1, &obj_rtld); 3307 if (res == 0) { 3308 req->sym_out = req1.sym_out; 3309 req->defobj_out = req1.defobj_out; 3310 assert(req->defobj_out != NULL); 3311 } 3312 } 3313 3314 return (req->sym_out != NULL ? 0 : ESRCH); 3315 } 3316 3317 static int 3318 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3319 { 3320 const Elf_Sym *def; 3321 const Obj_Entry *defobj; 3322 const Objlist_Entry *elm; 3323 SymLook req1; 3324 int res; 3325 3326 def = NULL; 3327 defobj = NULL; 3328 STAILQ_FOREACH(elm, objlist, link) { 3329 if (donelist_check(dlp, elm->obj)) 3330 continue; 3331 symlook_init_from_req(&req1, req); 3332 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3333 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3334 def = req1.sym_out; 3335 defobj = req1.defobj_out; 3336 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3337 break; 3338 } 3339 } 3340 } 3341 if (def != NULL) { 3342 req->sym_out = def; 3343 req->defobj_out = defobj; 3344 return (0); 3345 } 3346 return (ESRCH); 3347 } 3348 3349 /* 3350 * Search the chain of DAGS cointed to by the given Needed_Entry 3351 * for a symbol of the given name. Each DAG is scanned completely 3352 * before advancing to the next one. Returns a pointer to the symbol, 3353 * or NULL if no definition was found. 3354 */ 3355 static int 3356 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3357 { 3358 const Elf_Sym *def; 3359 const Needed_Entry *n; 3360 const Obj_Entry *defobj; 3361 SymLook req1; 3362 int res; 3363 3364 def = NULL; 3365 defobj = NULL; 3366 symlook_init_from_req(&req1, req); 3367 for (n = needed; n != NULL; n = n->next) { 3368 if (n->obj == NULL || 3369 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3370 continue; 3371 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3372 def = req1.sym_out; 3373 defobj = req1.defobj_out; 3374 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3375 break; 3376 } 3377 } 3378 if (def != NULL) { 3379 req->sym_out = def; 3380 req->defobj_out = defobj; 3381 return (0); 3382 } 3383 return (ESRCH); 3384 } 3385 3386 /* 3387 * Search the symbol table of a single shared object for a symbol of 3388 * the given name and version, if requested. Returns a pointer to the 3389 * symbol, or NULL if no definition was found. If the object is 3390 * filter, return filtered symbol from filtee. 3391 * 3392 * The symbol's hash value is passed in for efficiency reasons; that 3393 * eliminates many recomputations of the hash value. 3394 */ 3395 int 3396 symlook_obj(SymLook *req, const Obj_Entry *obj) 3397 { 3398 DoneList donelist; 3399 SymLook req1; 3400 int flags, res, mres; 3401 3402 mres = symlook_obj1(req, obj); 3403 if (mres == 0) { 3404 if (obj->needed_filtees != NULL) { 3405 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3406 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3407 donelist_init(&donelist); 3408 symlook_init_from_req(&req1, req); 3409 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3410 if (res == 0) { 3411 req->sym_out = req1.sym_out; 3412 req->defobj_out = req1.defobj_out; 3413 } 3414 return (res); 3415 } 3416 if (obj->needed_aux_filtees != NULL) { 3417 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3418 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3419 donelist_init(&donelist); 3420 symlook_init_from_req(&req1, req); 3421 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3422 if (res == 0) { 3423 req->sym_out = req1.sym_out; 3424 req->defobj_out = req1.defobj_out; 3425 return (res); 3426 } 3427 } 3428 } 3429 return (mres); 3430 } 3431 3432 static int 3433 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3434 { 3435 unsigned long symnum; 3436 const Elf_Sym *vsymp; 3437 Elf_Versym verndx; 3438 int vcount; 3439 3440 if (obj->buckets == NULL) 3441 return (ESRCH); 3442 3443 vsymp = NULL; 3444 vcount = 0; 3445 symnum = obj->buckets[req->hash % obj->nbuckets]; 3446 3447 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3448 const Elf_Sym *symp; 3449 const char *strp; 3450 3451 if (symnum >= obj->nchains) 3452 return (ESRCH); /* Bad object */ 3453 3454 symp = obj->symtab + symnum; 3455 strp = obj->strtab + symp->st_name; 3456 3457 switch (ELF_ST_TYPE(symp->st_info)) { 3458 case STT_FUNC: 3459 case STT_NOTYPE: 3460 case STT_OBJECT: 3461 case STT_GNU_IFUNC: 3462 if (symp->st_value == 0) 3463 continue; 3464 /* fallthrough */ 3465 case STT_TLS: 3466 if (symp->st_shndx != SHN_UNDEF) 3467 break; 3468 #ifndef __mips__ 3469 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3470 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3471 break; 3472 /* fallthrough */ 3473 #endif 3474 default: 3475 continue; 3476 } 3477 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3478 continue; 3479 3480 if (req->ventry == NULL) { 3481 if (obj->versyms != NULL) { 3482 verndx = VER_NDX(obj->versyms[symnum]); 3483 if (verndx > obj->vernum) { 3484 _rtld_error("%s: symbol %s references wrong version %d", 3485 obj->path, obj->strtab + symnum, verndx); 3486 continue; 3487 } 3488 /* 3489 * If we are not called from dlsym (i.e. this is a normal 3490 * relocation from unversioned binary), accept the symbol 3491 * immediately if it happens to have first version after 3492 * this shared object became versioned. Otherwise, if 3493 * symbol is versioned and not hidden, remember it. If it 3494 * is the only symbol with this name exported by the 3495 * shared object, it will be returned as a match at the 3496 * end of the function. If symbol is global (verndx < 2) 3497 * accept it unconditionally. 3498 */ 3499 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3500 verndx == VER_NDX_GIVEN) { 3501 req->sym_out = symp; 3502 req->defobj_out = obj; 3503 return (0); 3504 } 3505 else if (verndx >= VER_NDX_GIVEN) { 3506 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3507 if (vsymp == NULL) 3508 vsymp = symp; 3509 vcount ++; 3510 } 3511 continue; 3512 } 3513 } 3514 req->sym_out = symp; 3515 req->defobj_out = obj; 3516 return (0); 3517 } else { 3518 if (obj->versyms == NULL) { 3519 if (object_match_name(obj, req->ventry->name)) { 3520 _rtld_error("%s: object %s should provide version %s for " 3521 "symbol %s", obj_rtld.path, obj->path, 3522 req->ventry->name, obj->strtab + symnum); 3523 continue; 3524 } 3525 } else { 3526 verndx = VER_NDX(obj->versyms[symnum]); 3527 if (verndx > obj->vernum) { 3528 _rtld_error("%s: symbol %s references wrong version %d", 3529 obj->path, obj->strtab + symnum, verndx); 3530 continue; 3531 } 3532 if (obj->vertab[verndx].hash != req->ventry->hash || 3533 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3534 /* 3535 * Version does not match. Look if this is a global symbol 3536 * and if it is not hidden. If global symbol (verndx < 2) 3537 * is available, use it. Do not return symbol if we are 3538 * called by dlvsym, because dlvsym looks for a specific 3539 * version and default one is not what dlvsym wants. 3540 */ 3541 if ((req->flags & SYMLOOK_DLSYM) || 3542 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3543 (verndx >= VER_NDX_GIVEN)) 3544 continue; 3545 } 3546 } 3547 req->sym_out = symp; 3548 req->defobj_out = obj; 3549 return (0); 3550 } 3551 } 3552 if (vcount == 1) { 3553 req->sym_out = vsymp; 3554 req->defobj_out = obj; 3555 return (0); 3556 } 3557 return (ESRCH); 3558 } 3559 3560 static void 3561 trace_loaded_objects(Obj_Entry *obj) 3562 { 3563 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3564 int c; 3565 3566 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3567 main_local = ""; 3568 3569 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3570 fmt1 = "\t%o => %p (%x)\n"; 3571 3572 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3573 fmt2 = "\t%o (%x)\n"; 3574 3575 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3576 3577 for (; obj; obj = obj->next) { 3578 Needed_Entry *needed; 3579 char *name, *path; 3580 bool is_lib; 3581 3582 if (list_containers && obj->needed != NULL) 3583 rtld_printf("%s:\n", obj->path); 3584 for (needed = obj->needed; needed; needed = needed->next) { 3585 if (needed->obj != NULL) { 3586 if (needed->obj->traced && !list_containers) 3587 continue; 3588 needed->obj->traced = true; 3589 path = needed->obj->path; 3590 } else 3591 path = "not found"; 3592 3593 name = (char *)obj->strtab + needed->name; 3594 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3595 3596 fmt = is_lib ? fmt1 : fmt2; 3597 while ((c = *fmt++) != '\0') { 3598 switch (c) { 3599 default: 3600 rtld_putchar(c); 3601 continue; 3602 case '\\': 3603 switch (c = *fmt) { 3604 case '\0': 3605 continue; 3606 case 'n': 3607 rtld_putchar('\n'); 3608 break; 3609 case 't': 3610 rtld_putchar('\t'); 3611 break; 3612 } 3613 break; 3614 case '%': 3615 switch (c = *fmt) { 3616 case '\0': 3617 continue; 3618 case '%': 3619 default: 3620 rtld_putchar(c); 3621 break; 3622 case 'A': 3623 rtld_putstr(main_local); 3624 break; 3625 case 'a': 3626 rtld_putstr(obj_main->path); 3627 break; 3628 case 'o': 3629 rtld_putstr(name); 3630 break; 3631 #if 0 3632 case 'm': 3633 rtld_printf("%d", sodp->sod_major); 3634 break; 3635 case 'n': 3636 rtld_printf("%d", sodp->sod_minor); 3637 break; 3638 #endif 3639 case 'p': 3640 rtld_putstr(path); 3641 break; 3642 case 'x': 3643 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 3644 0); 3645 break; 3646 } 3647 break; 3648 } 3649 ++fmt; 3650 } 3651 } 3652 } 3653 } 3654 3655 /* 3656 * Unload a dlopened object and its dependencies from memory and from 3657 * our data structures. It is assumed that the DAG rooted in the 3658 * object has already been unreferenced, and that the object has a 3659 * reference count of 0. 3660 */ 3661 static void 3662 unload_object(Obj_Entry *root) 3663 { 3664 Obj_Entry *obj; 3665 Obj_Entry **linkp; 3666 3667 assert(root->refcount == 0); 3668 3669 /* 3670 * Pass over the DAG removing unreferenced objects from 3671 * appropriate lists. 3672 */ 3673 unlink_object(root); 3674 3675 /* Unmap all objects that are no longer referenced. */ 3676 linkp = &obj_list->next; 3677 while ((obj = *linkp) != NULL) { 3678 if (obj->refcount == 0) { 3679 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3680 obj->path); 3681 dbg("unloading \"%s\"", obj->path); 3682 unload_filtees(root); 3683 munmap(obj->mapbase, obj->mapsize); 3684 linkmap_delete(obj); 3685 *linkp = obj->next; 3686 obj_count--; 3687 obj_free(obj); 3688 } else 3689 linkp = &obj->next; 3690 } 3691 obj_tail = linkp; 3692 } 3693 3694 static void 3695 unlink_object(Obj_Entry *root) 3696 { 3697 Objlist_Entry *elm; 3698 3699 if (root->refcount == 0) { 3700 /* Remove the object from the RTLD_GLOBAL list. */ 3701 objlist_remove(&list_global, root); 3702 3703 /* Remove the object from all objects' DAG lists. */ 3704 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3705 objlist_remove(&elm->obj->dldags, root); 3706 if (elm->obj != root) 3707 unlink_object(elm->obj); 3708 } 3709 } 3710 } 3711 3712 static void 3713 ref_dag(Obj_Entry *root) 3714 { 3715 Objlist_Entry *elm; 3716 3717 assert(root->dag_inited); 3718 STAILQ_FOREACH(elm, &root->dagmembers, link) 3719 elm->obj->refcount++; 3720 } 3721 3722 static void 3723 unref_dag(Obj_Entry *root) 3724 { 3725 Objlist_Entry *elm; 3726 3727 assert(root->dag_inited); 3728 STAILQ_FOREACH(elm, &root->dagmembers, link) 3729 elm->obj->refcount--; 3730 } 3731 3732 /* 3733 * Common code for MD __tls_get_addr(). 3734 */ 3735 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 3736 static void * 3737 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 3738 { 3739 Elf_Addr *newdtv, *dtv; 3740 RtldLockState lockstate; 3741 int to_copy; 3742 3743 dtv = *dtvp; 3744 /* Check dtv generation in case new modules have arrived */ 3745 if (dtv[0] != tls_dtv_generation) { 3746 wlock_acquire(rtld_bind_lock, &lockstate); 3747 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3748 to_copy = dtv[1]; 3749 if (to_copy > tls_max_index) 3750 to_copy = tls_max_index; 3751 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3752 newdtv[0] = tls_dtv_generation; 3753 newdtv[1] = tls_max_index; 3754 free(dtv); 3755 lock_release(rtld_bind_lock, &lockstate); 3756 dtv = *dtvp = newdtv; 3757 } 3758 3759 /* Dynamically allocate module TLS if necessary */ 3760 if (dtv[index + 1] == 0) { 3761 /* Signal safe, wlock will block out signals. */ 3762 wlock_acquire(rtld_bind_lock, &lockstate); 3763 if (!dtv[index + 1]) 3764 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3765 lock_release(rtld_bind_lock, &lockstate); 3766 } 3767 return ((void *)(dtv[index + 1] + offset)); 3768 } 3769 3770 void * 3771 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 3772 { 3773 Elf_Addr *dtv; 3774 3775 dtv = *dtvp; 3776 /* Check dtv generation in case new modules have arrived */ 3777 if (__predict_true(dtv[0] == tls_dtv_generation && 3778 dtv[index + 1] != 0)) 3779 return ((void *)(dtv[index + 1] + offset)); 3780 return (tls_get_addr_slow(dtvp, index, offset)); 3781 } 3782 3783 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 3784 3785 /* 3786 * Allocate Static TLS using the Variant I method. 3787 */ 3788 void * 3789 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3790 { 3791 Obj_Entry *obj; 3792 char *tcb; 3793 Elf_Addr **tls; 3794 Elf_Addr *dtv; 3795 Elf_Addr addr; 3796 int i; 3797 3798 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3799 return (oldtcb); 3800 3801 assert(tcbsize >= TLS_TCB_SIZE); 3802 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3803 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3804 3805 if (oldtcb != NULL) { 3806 memcpy(tls, oldtcb, tls_static_space); 3807 free(oldtcb); 3808 3809 /* Adjust the DTV. */ 3810 dtv = tls[0]; 3811 for (i = 0; i < dtv[1]; i++) { 3812 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3813 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3814 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3815 } 3816 } 3817 } else { 3818 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3819 tls[0] = dtv; 3820 dtv[0] = tls_dtv_generation; 3821 dtv[1] = tls_max_index; 3822 3823 for (obj = objs; obj; obj = obj->next) { 3824 if (obj->tlsoffset > 0) { 3825 addr = (Elf_Addr)tls + obj->tlsoffset; 3826 if (obj->tlsinitsize > 0) 3827 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3828 if (obj->tlssize > obj->tlsinitsize) 3829 memset((void*) (addr + obj->tlsinitsize), 0, 3830 obj->tlssize - obj->tlsinitsize); 3831 dtv[obj->tlsindex + 1] = addr; 3832 } 3833 } 3834 } 3835 3836 return (tcb); 3837 } 3838 3839 void 3840 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3841 { 3842 Elf_Addr *dtv; 3843 Elf_Addr tlsstart, tlsend; 3844 int dtvsize, i; 3845 3846 assert(tcbsize >= TLS_TCB_SIZE); 3847 3848 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3849 tlsend = tlsstart + tls_static_space; 3850 3851 dtv = *(Elf_Addr **)tlsstart; 3852 dtvsize = dtv[1]; 3853 for (i = 0; i < dtvsize; i++) { 3854 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3855 free((void*)dtv[i+2]); 3856 } 3857 } 3858 free(dtv); 3859 free(tcb); 3860 } 3861 3862 #endif 3863 3864 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 3865 3866 /* 3867 * Allocate Static TLS using the Variant II method. 3868 */ 3869 void * 3870 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3871 { 3872 Obj_Entry *obj; 3873 size_t size; 3874 char *tls; 3875 Elf_Addr *dtv, *olddtv; 3876 Elf_Addr segbase, oldsegbase, addr; 3877 int i; 3878 3879 size = round(tls_static_space, tcbalign); 3880 3881 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3882 tls = xcalloc(1, size + tcbsize); 3883 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3884 3885 segbase = (Elf_Addr)(tls + size); 3886 ((Elf_Addr*)segbase)[0] = segbase; 3887 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3888 3889 dtv[0] = tls_dtv_generation; 3890 dtv[1] = tls_max_index; 3891 3892 if (oldtls) { 3893 /* 3894 * Copy the static TLS block over whole. 3895 */ 3896 oldsegbase = (Elf_Addr) oldtls; 3897 memcpy((void *)(segbase - tls_static_space), 3898 (const void *)(oldsegbase - tls_static_space), 3899 tls_static_space); 3900 3901 /* 3902 * If any dynamic TLS blocks have been created tls_get_addr(), 3903 * move them over. 3904 */ 3905 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3906 for (i = 0; i < olddtv[1]; i++) { 3907 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3908 dtv[i+2] = olddtv[i+2]; 3909 olddtv[i+2] = 0; 3910 } 3911 } 3912 3913 /* 3914 * We assume that this block was the one we created with 3915 * allocate_initial_tls(). 3916 */ 3917 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3918 } else { 3919 for (obj = objs; obj; obj = obj->next) { 3920 if (obj->tlsoffset) { 3921 addr = segbase - obj->tlsoffset; 3922 memset((void*) (addr + obj->tlsinitsize), 3923 0, obj->tlssize - obj->tlsinitsize); 3924 if (obj->tlsinit) 3925 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3926 dtv[obj->tlsindex + 1] = addr; 3927 } 3928 } 3929 } 3930 3931 return (void*) segbase; 3932 } 3933 3934 void 3935 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3936 { 3937 size_t size; 3938 Elf_Addr* dtv; 3939 int dtvsize, i; 3940 Elf_Addr tlsstart, tlsend; 3941 3942 /* 3943 * Figure out the size of the initial TLS block so that we can 3944 * find stuff which ___tls_get_addr() allocated dynamically. 3945 */ 3946 size = round(tls_static_space, tcbalign); 3947 3948 dtv = ((Elf_Addr**)tls)[1]; 3949 dtvsize = dtv[1]; 3950 tlsend = (Elf_Addr) tls; 3951 tlsstart = tlsend - size; 3952 for (i = 0; i < dtvsize; i++) { 3953 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3954 free((void*) dtv[i+2]); 3955 } 3956 } 3957 3958 free((void*) tlsstart); 3959 free((void*) dtv); 3960 } 3961 3962 #endif 3963 3964 /* 3965 * Allocate TLS block for module with given index. 3966 */ 3967 void * 3968 allocate_module_tls(int index) 3969 { 3970 Obj_Entry* obj; 3971 char* p; 3972 3973 for (obj = obj_list; obj; obj = obj->next) { 3974 if (obj->tlsindex == index) 3975 break; 3976 } 3977 if (!obj) { 3978 _rtld_error("Can't find module with TLS index %d", index); 3979 die(); 3980 } 3981 3982 p = malloc(obj->tlssize); 3983 if (p == NULL) { 3984 _rtld_error("Cannot allocate TLS block for index %d", index); 3985 die(); 3986 } 3987 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3988 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3989 3990 return p; 3991 } 3992 3993 bool 3994 allocate_tls_offset(Obj_Entry *obj) 3995 { 3996 size_t off; 3997 3998 if (obj->tls_done) 3999 return true; 4000 4001 if (obj->tlssize == 0) { 4002 obj->tls_done = true; 4003 return true; 4004 } 4005 4006 if (obj->tlsindex == 1) 4007 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4008 else 4009 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4010 obj->tlssize, obj->tlsalign); 4011 4012 /* 4013 * If we have already fixed the size of the static TLS block, we 4014 * must stay within that size. When allocating the static TLS, we 4015 * leave a small amount of space spare to be used for dynamically 4016 * loading modules which use static TLS. 4017 */ 4018 if (tls_static_space) { 4019 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4020 return false; 4021 } 4022 4023 tls_last_offset = obj->tlsoffset = off; 4024 tls_last_size = obj->tlssize; 4025 obj->tls_done = true; 4026 4027 return true; 4028 } 4029 4030 void 4031 free_tls_offset(Obj_Entry *obj) 4032 { 4033 4034 /* 4035 * If we were the last thing to allocate out of the static TLS 4036 * block, we give our space back to the 'allocator'. This is a 4037 * simplistic workaround to allow libGL.so.1 to be loaded and 4038 * unloaded multiple times. 4039 */ 4040 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4041 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4042 tls_last_offset -= obj->tlssize; 4043 tls_last_size = 0; 4044 } 4045 } 4046 4047 void * 4048 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4049 { 4050 void *ret; 4051 RtldLockState lockstate; 4052 4053 wlock_acquire(rtld_bind_lock, &lockstate); 4054 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4055 lock_release(rtld_bind_lock, &lockstate); 4056 return (ret); 4057 } 4058 4059 void 4060 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4061 { 4062 RtldLockState lockstate; 4063 4064 wlock_acquire(rtld_bind_lock, &lockstate); 4065 free_tls(tcb, tcbsize, tcbalign); 4066 lock_release(rtld_bind_lock, &lockstate); 4067 } 4068 4069 static void 4070 object_add_name(Obj_Entry *obj, const char *name) 4071 { 4072 Name_Entry *entry; 4073 size_t len; 4074 4075 len = strlen(name); 4076 entry = malloc(sizeof(Name_Entry) + len); 4077 4078 if (entry != NULL) { 4079 strcpy(entry->name, name); 4080 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4081 } 4082 } 4083 4084 static int 4085 object_match_name(const Obj_Entry *obj, const char *name) 4086 { 4087 Name_Entry *entry; 4088 4089 STAILQ_FOREACH(entry, &obj->names, link) { 4090 if (strcmp(name, entry->name) == 0) 4091 return (1); 4092 } 4093 return (0); 4094 } 4095 4096 static Obj_Entry * 4097 locate_dependency(const Obj_Entry *obj, const char *name) 4098 { 4099 const Objlist_Entry *entry; 4100 const Needed_Entry *needed; 4101 4102 STAILQ_FOREACH(entry, &list_main, link) { 4103 if (object_match_name(entry->obj, name)) 4104 return entry->obj; 4105 } 4106 4107 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4108 if (strcmp(obj->strtab + needed->name, name) == 0 || 4109 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4110 /* 4111 * If there is DT_NEEDED for the name we are looking for, 4112 * we are all set. Note that object might not be found if 4113 * dependency was not loaded yet, so the function can 4114 * return NULL here. This is expected and handled 4115 * properly by the caller. 4116 */ 4117 return (needed->obj); 4118 } 4119 } 4120 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4121 obj->path, name); 4122 die(); 4123 } 4124 4125 static int 4126 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4127 const Elf_Vernaux *vna) 4128 { 4129 const Elf_Verdef *vd; 4130 const char *vername; 4131 4132 vername = refobj->strtab + vna->vna_name; 4133 vd = depobj->verdef; 4134 if (vd == NULL) { 4135 _rtld_error("%s: version %s required by %s not defined", 4136 depobj->path, vername, refobj->path); 4137 return (-1); 4138 } 4139 for (;;) { 4140 if (vd->vd_version != VER_DEF_CURRENT) { 4141 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4142 depobj->path, vd->vd_version); 4143 return (-1); 4144 } 4145 if (vna->vna_hash == vd->vd_hash) { 4146 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4147 ((char *)vd + vd->vd_aux); 4148 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4149 return (0); 4150 } 4151 if (vd->vd_next == 0) 4152 break; 4153 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4154 } 4155 if (vna->vna_flags & VER_FLG_WEAK) 4156 return (0); 4157 _rtld_error("%s: version %s required by %s not found", 4158 depobj->path, vername, refobj->path); 4159 return (-1); 4160 } 4161 4162 static int 4163 rtld_verify_object_versions(Obj_Entry *obj) 4164 { 4165 const Elf_Verneed *vn; 4166 const Elf_Verdef *vd; 4167 const Elf_Verdaux *vda; 4168 const Elf_Vernaux *vna; 4169 const Obj_Entry *depobj; 4170 int maxvernum, vernum; 4171 4172 if (obj->ver_checked) 4173 return (0); 4174 obj->ver_checked = true; 4175 4176 maxvernum = 0; 4177 /* 4178 * Walk over defined and required version records and figure out 4179 * max index used by any of them. Do very basic sanity checking 4180 * while there. 4181 */ 4182 vn = obj->verneed; 4183 while (vn != NULL) { 4184 if (vn->vn_version != VER_NEED_CURRENT) { 4185 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4186 obj->path, vn->vn_version); 4187 return (-1); 4188 } 4189 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4190 for (;;) { 4191 vernum = VER_NEED_IDX(vna->vna_other); 4192 if (vernum > maxvernum) 4193 maxvernum = vernum; 4194 if (vna->vna_next == 0) 4195 break; 4196 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4197 } 4198 if (vn->vn_next == 0) 4199 break; 4200 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4201 } 4202 4203 vd = obj->verdef; 4204 while (vd != NULL) { 4205 if (vd->vd_version != VER_DEF_CURRENT) { 4206 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4207 obj->path, vd->vd_version); 4208 return (-1); 4209 } 4210 vernum = VER_DEF_IDX(vd->vd_ndx); 4211 if (vernum > maxvernum) 4212 maxvernum = vernum; 4213 if (vd->vd_next == 0) 4214 break; 4215 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4216 } 4217 4218 if (maxvernum == 0) 4219 return (0); 4220 4221 /* 4222 * Store version information in array indexable by version index. 4223 * Verify that object version requirements are satisfied along the 4224 * way. 4225 */ 4226 obj->vernum = maxvernum + 1; 4227 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4228 4229 vd = obj->verdef; 4230 while (vd != NULL) { 4231 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4232 vernum = VER_DEF_IDX(vd->vd_ndx); 4233 assert(vernum <= maxvernum); 4234 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4235 obj->vertab[vernum].hash = vd->vd_hash; 4236 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4237 obj->vertab[vernum].file = NULL; 4238 obj->vertab[vernum].flags = 0; 4239 } 4240 if (vd->vd_next == 0) 4241 break; 4242 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4243 } 4244 4245 vn = obj->verneed; 4246 while (vn != NULL) { 4247 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4248 if (depobj == NULL) 4249 return (-1); 4250 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4251 for (;;) { 4252 if (check_object_provided_version(obj, depobj, vna)) 4253 return (-1); 4254 vernum = VER_NEED_IDX(vna->vna_other); 4255 assert(vernum <= maxvernum); 4256 obj->vertab[vernum].hash = vna->vna_hash; 4257 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4258 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4259 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4260 VER_INFO_HIDDEN : 0; 4261 if (vna->vna_next == 0) 4262 break; 4263 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4264 } 4265 if (vn->vn_next == 0) 4266 break; 4267 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4268 } 4269 return 0; 4270 } 4271 4272 static int 4273 rtld_verify_versions(const Objlist *objlist) 4274 { 4275 Objlist_Entry *entry; 4276 int rc; 4277 4278 rc = 0; 4279 STAILQ_FOREACH(entry, objlist, link) { 4280 /* 4281 * Skip dummy objects or objects that have their version requirements 4282 * already checked. 4283 */ 4284 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4285 continue; 4286 if (rtld_verify_object_versions(entry->obj) == -1) { 4287 rc = -1; 4288 if (ld_tracing == NULL) 4289 break; 4290 } 4291 } 4292 if (rc == 0 || ld_tracing != NULL) 4293 rc = rtld_verify_object_versions(&obj_rtld); 4294 return rc; 4295 } 4296 4297 const Ver_Entry * 4298 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4299 { 4300 Elf_Versym vernum; 4301 4302 if (obj->vertab) { 4303 vernum = VER_NDX(obj->versyms[symnum]); 4304 if (vernum >= obj->vernum) { 4305 _rtld_error("%s: symbol %s has wrong verneed value %d", 4306 obj->path, obj->strtab + symnum, vernum); 4307 } else if (obj->vertab[vernum].hash != 0) { 4308 return &obj->vertab[vernum]; 4309 } 4310 } 4311 return NULL; 4312 } 4313 4314 int 4315 _rtld_get_stack_prot(void) 4316 { 4317 4318 return (stack_prot); 4319 } 4320 4321 static void 4322 map_stacks_exec(RtldLockState *lockstate) 4323 { 4324 void (*thr_map_stacks_exec)(void); 4325 4326 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4327 return; 4328 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4329 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4330 if (thr_map_stacks_exec != NULL) { 4331 stack_prot |= PROT_EXEC; 4332 thr_map_stacks_exec(); 4333 } 4334 } 4335 4336 void 4337 symlook_init(SymLook *dst, const char *name) 4338 { 4339 4340 bzero(dst, sizeof(*dst)); 4341 dst->name = name; 4342 dst->hash = elf_hash(name); 4343 } 4344 4345 static void 4346 symlook_init_from_req(SymLook *dst, const SymLook *src) 4347 { 4348 4349 dst->name = src->name; 4350 dst->hash = src->hash; 4351 dst->ventry = src->ventry; 4352 dst->flags = src->flags; 4353 dst->defobj_out = NULL; 4354 dst->sym_out = NULL; 4355 dst->lockstate = src->lockstate; 4356 } 4357 4358 /* 4359 * Overrides for libc_pic-provided functions. 4360 */ 4361 4362 int 4363 __getosreldate(void) 4364 { 4365 size_t len; 4366 int oid[2]; 4367 int error, osrel; 4368 4369 if (osreldate != 0) 4370 return (osreldate); 4371 4372 oid[0] = CTL_KERN; 4373 oid[1] = KERN_OSRELDATE; 4374 osrel = 0; 4375 len = sizeof(osrel); 4376 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4377 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4378 osreldate = osrel; 4379 return (osreldate); 4380 } 4381 4382 void 4383 exit(int status) 4384 { 4385 4386 _exit(status); 4387 } 4388 4389 void (*__cleanup)(void); 4390 int __isthreaded = 0; 4391 int _thread_autoinit_dummy_decl = 1; 4392 4393 /* 4394 * No unresolved symbols for rtld. 4395 */ 4396 void 4397 __pthread_cxa_finalize(struct dl_phdr_info *a) 4398 { 4399 } 4400 4401 void 4402 __stack_chk_fail(void) 4403 { 4404 4405 _rtld_error("stack overflow detected; terminated"); 4406 die(); 4407 } 4408 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4409 4410 void 4411 __chk_fail(void) 4412 { 4413 4414 _rtld_error("buffer overflow detected; terminated"); 4415 die(); 4416 } 4417 4418 const char * 4419 rtld_strerror(int errnum) 4420 { 4421 4422 if (errnum < 0 || errnum >= sys_nerr) 4423 return ("Unknown error"); 4424 return (sys_errlist[errnum]); 4425 } 4426