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, RtldLockState *lockstate); 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] != NULL && 355 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 356 i = aux_info[AT_CANARYLEN]->a_un.a_val; 357 if (i > sizeof(__stack_chk_guard)) 358 i = sizeof(__stack_chk_guard); 359 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 360 } else { 361 mib[0] = CTL_KERN; 362 mib[1] = KERN_ARND; 363 364 len = sizeof(__stack_chk_guard); 365 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 366 len != sizeof(__stack_chk_guard)) { 367 /* If sysctl was unsuccessful, use the "terminator canary". */ 368 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 369 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 370 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 371 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 372 } 373 } 374 375 trust = !issetugid(); 376 377 ld_bind_now = getenv(LD_ "BIND_NOW"); 378 /* 379 * If the process is tainted, then we un-set the dangerous environment 380 * variables. The process will be marked as tainted until setuid(2) 381 * is called. If any child process calls setuid(2) we do not want any 382 * future processes to honor the potentially un-safe variables. 383 */ 384 if (!trust) { 385 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 386 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 387 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 388 unsetenv(LD_ "LOADFLTR")) { 389 _rtld_error("environment corrupt; aborting"); 390 die(); 391 } 392 } 393 ld_debug = getenv(LD_ "DEBUG"); 394 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 395 libmap_override = getenv(LD_ "LIBMAP"); 396 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 397 ld_preload = getenv(LD_ "PRELOAD"); 398 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 399 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 400 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 401 (ld_library_path != NULL) || (ld_preload != NULL) || 402 (ld_elf_hints_path != NULL) || ld_loadfltr; 403 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 404 ld_utrace = getenv(LD_ "UTRACE"); 405 406 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 407 ld_elf_hints_path = _PATH_ELF_HINTS; 408 409 if (ld_debug != NULL && *ld_debug != '\0') 410 debug = 1; 411 dbg("%s is initialized, base address = %p", __progname, 412 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 413 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 414 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 415 416 dbg("initializing thread locks"); 417 lockdflt_init(); 418 419 /* 420 * Load the main program, or process its program header if it is 421 * already loaded. 422 */ 423 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 424 int fd = aux_info[AT_EXECFD]->a_un.a_val; 425 dbg("loading main program"); 426 obj_main = map_object(fd, argv0, NULL); 427 close(fd); 428 if (obj_main == NULL) 429 die(); 430 max_stack_flags = obj->stack_flags; 431 } else { /* Main program already loaded. */ 432 const Elf_Phdr *phdr; 433 int phnum; 434 caddr_t entry; 435 436 dbg("processing main program's program header"); 437 assert(aux_info[AT_PHDR] != NULL); 438 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 439 assert(aux_info[AT_PHNUM] != NULL); 440 phnum = aux_info[AT_PHNUM]->a_un.a_val; 441 assert(aux_info[AT_PHENT] != NULL); 442 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 443 assert(aux_info[AT_ENTRY] != NULL); 444 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 445 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 446 die(); 447 } 448 449 if (aux_info[AT_EXECPATH] != 0) { 450 char *kexecpath; 451 char buf[MAXPATHLEN]; 452 453 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 454 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 455 if (kexecpath[0] == '/') 456 obj_main->path = kexecpath; 457 else if (getcwd(buf, sizeof(buf)) == NULL || 458 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 459 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 460 obj_main->path = xstrdup(argv0); 461 else 462 obj_main->path = xstrdup(buf); 463 } else { 464 dbg("No AT_EXECPATH"); 465 obj_main->path = xstrdup(argv0); 466 } 467 dbg("obj_main path %s", obj_main->path); 468 obj_main->mainprog = true; 469 470 if (aux_info[AT_STACKPROT] != NULL && 471 aux_info[AT_STACKPROT]->a_un.a_val != 0) 472 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 473 474 /* 475 * Get the actual dynamic linker pathname from the executable if 476 * possible. (It should always be possible.) That ensures that 477 * gdb will find the right dynamic linker even if a non-standard 478 * one is being used. 479 */ 480 if (obj_main->interp != NULL && 481 strcmp(obj_main->interp, obj_rtld.path) != 0) { 482 free(obj_rtld.path); 483 obj_rtld.path = xstrdup(obj_main->interp); 484 __progname = obj_rtld.path; 485 } 486 487 digest_dynamic(obj_main, 0); 488 489 linkmap_add(obj_main); 490 linkmap_add(&obj_rtld); 491 492 /* Link the main program into the list of objects. */ 493 *obj_tail = obj_main; 494 obj_tail = &obj_main->next; 495 obj_count++; 496 obj_loads++; 497 498 /* Initialize a fake symbol for resolving undefined weak references. */ 499 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 500 sym_zero.st_shndx = SHN_UNDEF; 501 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 502 503 if (!libmap_disable) 504 libmap_disable = (bool)lm_init(libmap_override); 505 506 dbg("loading LD_PRELOAD libraries"); 507 if (load_preload_objects() == -1) 508 die(); 509 preload_tail = obj_tail; 510 511 dbg("loading needed objects"); 512 if (load_needed_objects(obj_main, 0) == -1) 513 die(); 514 515 /* Make a list of all objects loaded at startup. */ 516 for (obj = obj_list; obj != NULL; obj = obj->next) { 517 objlist_push_tail(&list_main, obj); 518 obj->refcount++; 519 } 520 521 dbg("checking for required versions"); 522 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 523 die(); 524 525 if (ld_tracing) { /* We're done */ 526 trace_loaded_objects(obj_main); 527 exit(0); 528 } 529 530 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 531 dump_relocations(obj_main); 532 exit (0); 533 } 534 535 /* 536 * Processing tls relocations requires having the tls offsets 537 * initialized. Prepare offsets before starting initial 538 * relocation processing. 539 */ 540 dbg("initializing initial thread local storage offsets"); 541 STAILQ_FOREACH(entry, &list_main, link) { 542 /* 543 * Allocate all the initial objects out of the static TLS 544 * block even if they didn't ask for it. 545 */ 546 allocate_tls_offset(entry->obj); 547 } 548 549 if (relocate_objects(obj_main, 550 ld_bind_now != NULL && *ld_bind_now != '\0', 551 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 552 die(); 553 554 dbg("doing copy relocations"); 555 if (do_copy_relocations(obj_main) == -1) 556 die(); 557 558 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 559 dump_relocations(obj_main); 560 exit (0); 561 } 562 563 /* 564 * Setup TLS for main thread. This must be done after the 565 * relocations are processed, since tls initialization section 566 * might be the subject for relocations. 567 */ 568 dbg("initializing initial thread local storage"); 569 allocate_initial_tls(obj_list); 570 571 dbg("initializing key program variables"); 572 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 573 set_program_var("environ", env); 574 set_program_var("__elf_aux_vector", aux); 575 576 /* Make a list of init functions to call. */ 577 objlist_init(&initlist); 578 initlist_add_objects(obj_list, preload_tail, &initlist); 579 580 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 581 582 map_stacks_exec(NULL); 583 584 dbg("resolving ifuncs"); 585 if (resolve_objects_ifunc(obj_main, 586 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 587 NULL) == -1) 588 die(); 589 590 if (!obj_main->crt_no_init) { 591 /* 592 * Make sure we don't call the main program's init and fini 593 * functions for binaries linked with old crt1 which calls 594 * _init itself. 595 */ 596 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 597 obj_main->preinit_array = obj_main->init_array = 598 obj_main->fini_array = (Elf_Addr)NULL; 599 } 600 601 wlock_acquire(rtld_bind_lock, &lockstate); 602 if (obj_main->crt_no_init) 603 preinit_main(); 604 objlist_call_init(&initlist, &lockstate); 605 objlist_clear(&initlist); 606 dbg("loading filtees"); 607 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 608 if (ld_loadfltr || obj->z_loadfltr) 609 load_filtees(obj, 0, &lockstate); 610 } 611 lock_release(rtld_bind_lock, &lockstate); 612 613 dbg("transferring control to program entry point = %p", obj_main->entry); 614 615 /* Return the exit procedure and the program entry point. */ 616 *exit_proc = rtld_exit; 617 *objp = obj_main; 618 return (func_ptr_type) obj_main->entry; 619 } 620 621 void * 622 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 623 { 624 void *ptr; 625 Elf_Addr target; 626 627 ptr = (void *)make_function_pointer(def, obj); 628 target = ((Elf_Addr (*)(void))ptr)(); 629 return ((void *)target); 630 } 631 632 Elf_Addr 633 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 634 { 635 const Elf_Rel *rel; 636 const Elf_Sym *def; 637 const Obj_Entry *defobj; 638 Elf_Addr *where; 639 Elf_Addr target; 640 RtldLockState lockstate; 641 642 rlock_acquire(rtld_bind_lock, &lockstate); 643 if (sigsetjmp(lockstate.env, 0) != 0) 644 lock_upgrade(rtld_bind_lock, &lockstate); 645 if (obj->pltrel) 646 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 647 else 648 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 649 650 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 651 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 652 &lockstate); 653 if (def == NULL) 654 die(); 655 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 656 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 657 else 658 target = (Elf_Addr)(defobj->relocbase + def->st_value); 659 660 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 661 defobj->strtab + def->st_name, basename(obj->path), 662 (void *)target, basename(defobj->path)); 663 664 /* 665 * Write the new contents for the jmpslot. Note that depending on 666 * architecture, the value which we need to return back to the 667 * lazy binding trampoline may or may not be the target 668 * address. The value returned from reloc_jmpslot() is the value 669 * that the trampoline needs. 670 */ 671 target = reloc_jmpslot(where, target, defobj, obj, rel); 672 lock_release(rtld_bind_lock, &lockstate); 673 return target; 674 } 675 676 /* 677 * Error reporting function. Use it like printf. If formats the message 678 * into a buffer, and sets things up so that the next call to dlerror() 679 * will return the message. 680 */ 681 void 682 _rtld_error(const char *fmt, ...) 683 { 684 static char buf[512]; 685 va_list ap; 686 687 va_start(ap, fmt); 688 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 689 error_message = buf; 690 va_end(ap); 691 } 692 693 /* 694 * Return a dynamically-allocated copy of the current error message, if any. 695 */ 696 static char * 697 errmsg_save(void) 698 { 699 return error_message == NULL ? NULL : xstrdup(error_message); 700 } 701 702 /* 703 * Restore the current error message from a copy which was previously saved 704 * by errmsg_save(). The copy is freed. 705 */ 706 static void 707 errmsg_restore(char *saved_msg) 708 { 709 if (saved_msg == NULL) 710 error_message = NULL; 711 else { 712 _rtld_error("%s", saved_msg); 713 free(saved_msg); 714 } 715 } 716 717 static const char * 718 basename(const char *name) 719 { 720 const char *p = strrchr(name, '/'); 721 return p != NULL ? p + 1 : name; 722 } 723 724 static struct utsname uts; 725 726 static int 727 origin_subst_one(char **res, const char *real, const char *kw, const char *subst, 728 char *may_free) 729 { 730 const char *p, *p1; 731 char *res1; 732 int subst_len; 733 int kw_len; 734 735 res1 = *res = NULL; 736 p = real; 737 subst_len = kw_len = 0; 738 for (;;) { 739 p1 = strstr(p, kw); 740 if (p1 != NULL) { 741 if (subst_len == 0) { 742 subst_len = strlen(subst); 743 kw_len = strlen(kw); 744 } 745 if (*res == NULL) { 746 *res = xmalloc(PATH_MAX); 747 res1 = *res; 748 } 749 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) { 750 _rtld_error("Substitution of %s in %s cannot be performed", 751 kw, real); 752 if (may_free != NULL) 753 free(may_free); 754 free(res); 755 return (false); 756 } 757 memcpy(res1, p, p1 - p); 758 res1 += p1 - p; 759 memcpy(res1, subst, subst_len); 760 res1 += subst_len; 761 p = p1 + kw_len; 762 } else { 763 if (*res == NULL) { 764 if (may_free != NULL) 765 *res = may_free; 766 else 767 *res = xstrdup(real); 768 return (true); 769 } 770 *res1 = '\0'; 771 if (may_free != NULL) 772 free(may_free); 773 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) { 774 free(res); 775 return (false); 776 } 777 return (true); 778 } 779 } 780 } 781 782 static char * 783 origin_subst(const char *real, const char *origin_path) 784 { 785 char *res1, *res2, *res3, *res4; 786 787 if (uts.sysname[0] == '\0') { 788 if (uname(&uts) != 0) { 789 _rtld_error("utsname failed: %d", errno); 790 return (NULL); 791 } 792 } 793 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) || 794 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) || 795 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) || 796 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3)) 797 return (NULL); 798 return (res4); 799 } 800 801 static void 802 die(void) 803 { 804 const char *msg = dlerror(); 805 806 if (msg == NULL) 807 msg = "Fatal error"; 808 rtld_fdputstr(STDERR_FILENO, msg); 809 rtld_fdputchar(STDERR_FILENO, '\n'); 810 _exit(1); 811 } 812 813 /* 814 * Process a shared object's DYNAMIC section, and save the important 815 * information in its Obj_Entry structure. 816 */ 817 static void 818 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 819 const Elf_Dyn **dyn_soname) 820 { 821 const Elf_Dyn *dynp; 822 Needed_Entry **needed_tail = &obj->needed; 823 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 824 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 825 int plttype = DT_REL; 826 827 *dyn_rpath = NULL; 828 *dyn_soname = NULL; 829 830 obj->bind_now = false; 831 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 832 switch (dynp->d_tag) { 833 834 case DT_REL: 835 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 836 break; 837 838 case DT_RELSZ: 839 obj->relsize = dynp->d_un.d_val; 840 break; 841 842 case DT_RELENT: 843 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 844 break; 845 846 case DT_JMPREL: 847 obj->pltrel = (const Elf_Rel *) 848 (obj->relocbase + dynp->d_un.d_ptr); 849 break; 850 851 case DT_PLTRELSZ: 852 obj->pltrelsize = dynp->d_un.d_val; 853 break; 854 855 case DT_RELA: 856 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 857 break; 858 859 case DT_RELASZ: 860 obj->relasize = dynp->d_un.d_val; 861 break; 862 863 case DT_RELAENT: 864 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 865 break; 866 867 case DT_PLTREL: 868 plttype = dynp->d_un.d_val; 869 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 870 break; 871 872 case DT_SYMTAB: 873 obj->symtab = (const Elf_Sym *) 874 (obj->relocbase + dynp->d_un.d_ptr); 875 break; 876 877 case DT_SYMENT: 878 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 879 break; 880 881 case DT_STRTAB: 882 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 883 break; 884 885 case DT_STRSZ: 886 obj->strsize = dynp->d_un.d_val; 887 break; 888 889 case DT_VERNEED: 890 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 891 dynp->d_un.d_val); 892 break; 893 894 case DT_VERNEEDNUM: 895 obj->verneednum = dynp->d_un.d_val; 896 break; 897 898 case DT_VERDEF: 899 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 900 dynp->d_un.d_val); 901 break; 902 903 case DT_VERDEFNUM: 904 obj->verdefnum = dynp->d_un.d_val; 905 break; 906 907 case DT_VERSYM: 908 obj->versyms = (const Elf_Versym *)(obj->relocbase + 909 dynp->d_un.d_val); 910 break; 911 912 case DT_HASH: 913 { 914 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 915 (obj->relocbase + dynp->d_un.d_ptr); 916 obj->nbuckets = hashtab[0]; 917 obj->nchains = hashtab[1]; 918 obj->buckets = hashtab + 2; 919 obj->chains = obj->buckets + obj->nbuckets; 920 } 921 break; 922 923 case DT_NEEDED: 924 if (!obj->rtld) { 925 Needed_Entry *nep = NEW(Needed_Entry); 926 nep->name = dynp->d_un.d_val; 927 nep->obj = NULL; 928 nep->next = NULL; 929 930 *needed_tail = nep; 931 needed_tail = &nep->next; 932 } 933 break; 934 935 case DT_FILTER: 936 if (!obj->rtld) { 937 Needed_Entry *nep = NEW(Needed_Entry); 938 nep->name = dynp->d_un.d_val; 939 nep->obj = NULL; 940 nep->next = NULL; 941 942 *needed_filtees_tail = nep; 943 needed_filtees_tail = &nep->next; 944 } 945 break; 946 947 case DT_AUXILIARY: 948 if (!obj->rtld) { 949 Needed_Entry *nep = NEW(Needed_Entry); 950 nep->name = dynp->d_un.d_val; 951 nep->obj = NULL; 952 nep->next = NULL; 953 954 *needed_aux_filtees_tail = nep; 955 needed_aux_filtees_tail = &nep->next; 956 } 957 break; 958 959 case DT_PLTGOT: 960 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 961 break; 962 963 case DT_TEXTREL: 964 obj->textrel = true; 965 break; 966 967 case DT_SYMBOLIC: 968 obj->symbolic = true; 969 break; 970 971 case DT_RPATH: 972 case DT_RUNPATH: /* XXX: process separately */ 973 /* 974 * We have to wait until later to process this, because we 975 * might not have gotten the address of the string table yet. 976 */ 977 *dyn_rpath = dynp; 978 break; 979 980 case DT_SONAME: 981 *dyn_soname = dynp; 982 break; 983 984 case DT_INIT: 985 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 986 break; 987 988 case DT_PREINIT_ARRAY: 989 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 990 break; 991 992 case DT_PREINIT_ARRAYSZ: 993 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 994 break; 995 996 case DT_INIT_ARRAY: 997 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 998 break; 999 1000 case DT_INIT_ARRAYSZ: 1001 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1002 break; 1003 1004 case DT_FINI: 1005 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1006 break; 1007 1008 case DT_FINI_ARRAY: 1009 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1010 break; 1011 1012 case DT_FINI_ARRAYSZ: 1013 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1014 break; 1015 1016 /* 1017 * Don't process DT_DEBUG on MIPS as the dynamic section 1018 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1019 */ 1020 1021 #ifndef __mips__ 1022 case DT_DEBUG: 1023 /* XXX - not implemented yet */ 1024 if (!early) 1025 dbg("Filling in DT_DEBUG entry"); 1026 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1027 break; 1028 #endif 1029 1030 case DT_FLAGS: 1031 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1032 obj->z_origin = true; 1033 if (dynp->d_un.d_val & DF_SYMBOLIC) 1034 obj->symbolic = true; 1035 if (dynp->d_un.d_val & DF_TEXTREL) 1036 obj->textrel = true; 1037 if (dynp->d_un.d_val & DF_BIND_NOW) 1038 obj->bind_now = true; 1039 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1040 ;*/ 1041 break; 1042 #ifdef __mips__ 1043 case DT_MIPS_LOCAL_GOTNO: 1044 obj->local_gotno = dynp->d_un.d_val; 1045 break; 1046 1047 case DT_MIPS_SYMTABNO: 1048 obj->symtabno = dynp->d_un.d_val; 1049 break; 1050 1051 case DT_MIPS_GOTSYM: 1052 obj->gotsym = dynp->d_un.d_val; 1053 break; 1054 1055 case DT_MIPS_RLD_MAP: 1056 #ifdef notyet 1057 if (!early) 1058 dbg("Filling in DT_DEBUG entry"); 1059 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1060 #endif 1061 break; 1062 #endif 1063 1064 case DT_FLAGS_1: 1065 if (dynp->d_un.d_val & DF_1_NOOPEN) 1066 obj->z_noopen = true; 1067 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1068 obj->z_origin = true; 1069 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1070 XXX ;*/ 1071 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1072 obj->bind_now = true; 1073 if (dynp->d_un.d_val & DF_1_NODELETE) 1074 obj->z_nodelete = true; 1075 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1076 obj->z_loadfltr = true; 1077 break; 1078 1079 default: 1080 if (!early) { 1081 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1082 (long)dynp->d_tag); 1083 } 1084 break; 1085 } 1086 } 1087 1088 obj->traced = false; 1089 1090 if (plttype == DT_RELA) { 1091 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1092 obj->pltrel = NULL; 1093 obj->pltrelasize = obj->pltrelsize; 1094 obj->pltrelsize = 0; 1095 } 1096 } 1097 1098 static void 1099 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1100 const Elf_Dyn *dyn_soname) 1101 { 1102 1103 if (obj->z_origin && obj->origin_path == NULL) { 1104 obj->origin_path = xmalloc(PATH_MAX); 1105 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1106 die(); 1107 } 1108 1109 if (dyn_rpath != NULL) { 1110 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1111 if (obj->z_origin) 1112 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1113 } 1114 1115 if (dyn_soname != NULL) 1116 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1117 } 1118 1119 static void 1120 digest_dynamic(Obj_Entry *obj, int early) 1121 { 1122 const Elf_Dyn *dyn_rpath; 1123 const Elf_Dyn *dyn_soname; 1124 1125 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname); 1126 digest_dynamic2(obj, dyn_rpath, dyn_soname); 1127 } 1128 1129 /* 1130 * Process a shared object's program header. This is used only for the 1131 * main program, when the kernel has already loaded the main program 1132 * into memory before calling the dynamic linker. It creates and 1133 * returns an Obj_Entry structure. 1134 */ 1135 static Obj_Entry * 1136 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1137 { 1138 Obj_Entry *obj; 1139 const Elf_Phdr *phlimit = phdr + phnum; 1140 const Elf_Phdr *ph; 1141 Elf_Addr note_start, note_end; 1142 int nsegs = 0; 1143 1144 obj = obj_new(); 1145 for (ph = phdr; ph < phlimit; ph++) { 1146 if (ph->p_type != PT_PHDR) 1147 continue; 1148 1149 obj->phdr = phdr; 1150 obj->phsize = ph->p_memsz; 1151 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1152 break; 1153 } 1154 1155 obj->stack_flags = PF_X | PF_R | PF_W; 1156 1157 for (ph = phdr; ph < phlimit; ph++) { 1158 switch (ph->p_type) { 1159 1160 case PT_INTERP: 1161 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1162 break; 1163 1164 case PT_LOAD: 1165 if (nsegs == 0) { /* First load segment */ 1166 obj->vaddrbase = trunc_page(ph->p_vaddr); 1167 obj->mapbase = obj->vaddrbase + obj->relocbase; 1168 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1169 obj->vaddrbase; 1170 } else { /* Last load segment */ 1171 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1172 obj->vaddrbase; 1173 } 1174 nsegs++; 1175 break; 1176 1177 case PT_DYNAMIC: 1178 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1179 break; 1180 1181 case PT_TLS: 1182 obj->tlsindex = 1; 1183 obj->tlssize = ph->p_memsz; 1184 obj->tlsalign = ph->p_align; 1185 obj->tlsinitsize = ph->p_filesz; 1186 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1187 break; 1188 1189 case PT_GNU_STACK: 1190 obj->stack_flags = ph->p_flags; 1191 break; 1192 1193 case PT_GNU_RELRO: 1194 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1195 obj->relro_size = round_page(ph->p_memsz); 1196 break; 1197 1198 case PT_NOTE: 1199 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1200 note_end = note_start + ph->p_filesz; 1201 digest_notes(obj, note_start, note_end); 1202 break; 1203 } 1204 } 1205 if (nsegs < 1) { 1206 _rtld_error("%s: too few PT_LOAD segments", path); 1207 return NULL; 1208 } 1209 1210 obj->entry = entry; 1211 return obj; 1212 } 1213 1214 void 1215 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1216 { 1217 const Elf_Note *note; 1218 const char *note_name; 1219 uintptr_t p; 1220 1221 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1222 note = (const Elf_Note *)((const char *)(note + 1) + 1223 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1224 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1225 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1226 note->n_descsz != sizeof(int32_t)) 1227 continue; 1228 if (note->n_type != ABI_NOTETYPE && 1229 note->n_type != CRT_NOINIT_NOTETYPE) 1230 continue; 1231 note_name = (const char *)(note + 1); 1232 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1233 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1234 continue; 1235 switch (note->n_type) { 1236 case ABI_NOTETYPE: 1237 /* FreeBSD osrel note */ 1238 p = (uintptr_t)(note + 1); 1239 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1240 obj->osrel = *(const int32_t *)(p); 1241 dbg("note osrel %d", obj->osrel); 1242 break; 1243 case CRT_NOINIT_NOTETYPE: 1244 /* FreeBSD 'crt does not call init' note */ 1245 obj->crt_no_init = true; 1246 dbg("note crt_no_init"); 1247 break; 1248 } 1249 } 1250 } 1251 1252 static Obj_Entry * 1253 dlcheck(void *handle) 1254 { 1255 Obj_Entry *obj; 1256 1257 for (obj = obj_list; obj != NULL; obj = obj->next) 1258 if (obj == (Obj_Entry *) handle) 1259 break; 1260 1261 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1262 _rtld_error("Invalid shared object handle %p", handle); 1263 return NULL; 1264 } 1265 return obj; 1266 } 1267 1268 /* 1269 * If the given object is already in the donelist, return true. Otherwise 1270 * add the object to the list and return false. 1271 */ 1272 static bool 1273 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1274 { 1275 unsigned int i; 1276 1277 for (i = 0; i < dlp->num_used; i++) 1278 if (dlp->objs[i] == obj) 1279 return true; 1280 /* 1281 * Our donelist allocation should always be sufficient. But if 1282 * our threads locking isn't working properly, more shared objects 1283 * could have been loaded since we allocated the list. That should 1284 * never happen, but we'll handle it properly just in case it does. 1285 */ 1286 if (dlp->num_used < dlp->num_alloc) 1287 dlp->objs[dlp->num_used++] = obj; 1288 return false; 1289 } 1290 1291 /* 1292 * Hash function for symbol table lookup. Don't even think about changing 1293 * this. It is specified by the System V ABI. 1294 */ 1295 unsigned long 1296 elf_hash(const char *name) 1297 { 1298 const unsigned char *p = (const unsigned char *) name; 1299 unsigned long h = 0; 1300 unsigned long g; 1301 1302 while (*p != '\0') { 1303 h = (h << 4) + *p++; 1304 if ((g = h & 0xf0000000) != 0) 1305 h ^= g >> 24; 1306 h &= ~g; 1307 } 1308 return h; 1309 } 1310 1311 /* 1312 * Find the library with the given name, and return its full pathname. 1313 * The returned string is dynamically allocated. Generates an error 1314 * message and returns NULL if the library cannot be found. 1315 * 1316 * If the second argument is non-NULL, then it refers to an already- 1317 * loaded shared object, whose library search path will be searched. 1318 * 1319 * The search order is: 1320 * LD_LIBRARY_PATH 1321 * rpath in the referencing file 1322 * ldconfig hints 1323 * /lib:/usr/lib 1324 */ 1325 static char * 1326 find_library(const char *xname, const Obj_Entry *refobj) 1327 { 1328 char *pathname; 1329 char *name; 1330 1331 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1332 if (xname[0] != '/' && !trust) { 1333 _rtld_error("Absolute pathname required for shared object \"%s\"", 1334 xname); 1335 return NULL; 1336 } 1337 if (refobj != NULL && refobj->z_origin) 1338 return origin_subst(xname, refobj->origin_path); 1339 else 1340 return xstrdup(xname); 1341 } 1342 1343 if (libmap_disable || (refobj == NULL) || 1344 (name = lm_find(refobj->path, xname)) == NULL) 1345 name = (char *)xname; 1346 1347 dbg(" Searching for \"%s\"", name); 1348 1349 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1350 (refobj != NULL && 1351 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1352 (pathname = search_library_path(name, gethints())) != NULL || 1353 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1354 return pathname; 1355 1356 if(refobj != NULL && refobj->path != NULL) { 1357 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1358 name, basename(refobj->path)); 1359 } else { 1360 _rtld_error("Shared object \"%s\" not found", name); 1361 } 1362 return NULL; 1363 } 1364 1365 /* 1366 * Given a symbol number in a referencing object, find the corresponding 1367 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1368 * no definition was found. Returns a pointer to the Obj_Entry of the 1369 * defining object via the reference parameter DEFOBJ_OUT. 1370 */ 1371 const Elf_Sym * 1372 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1373 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1374 RtldLockState *lockstate) 1375 { 1376 const Elf_Sym *ref; 1377 const Elf_Sym *def; 1378 const Obj_Entry *defobj; 1379 SymLook req; 1380 const char *name; 1381 int res; 1382 1383 /* 1384 * If we have already found this symbol, get the information from 1385 * the cache. 1386 */ 1387 if (symnum >= refobj->nchains) 1388 return NULL; /* Bad object */ 1389 if (cache != NULL && cache[symnum].sym != NULL) { 1390 *defobj_out = cache[symnum].obj; 1391 return cache[symnum].sym; 1392 } 1393 1394 ref = refobj->symtab + symnum; 1395 name = refobj->strtab + ref->st_name; 1396 def = NULL; 1397 defobj = NULL; 1398 1399 /* 1400 * We don't have to do a full scale lookup if the symbol is local. 1401 * We know it will bind to the instance in this load module; to 1402 * which we already have a pointer (ie ref). By not doing a lookup, 1403 * we not only improve performance, but it also avoids unresolvable 1404 * symbols when local symbols are not in the hash table. This has 1405 * been seen with the ia64 toolchain. 1406 */ 1407 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1408 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1409 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1410 symnum); 1411 } 1412 symlook_init(&req, name); 1413 req.flags = flags; 1414 req.ventry = fetch_ventry(refobj, symnum); 1415 req.lockstate = lockstate; 1416 res = symlook_default(&req, refobj); 1417 if (res == 0) { 1418 def = req.sym_out; 1419 defobj = req.defobj_out; 1420 } 1421 } else { 1422 def = ref; 1423 defobj = refobj; 1424 } 1425 1426 /* 1427 * If we found no definition and the reference is weak, treat the 1428 * symbol as having the value zero. 1429 */ 1430 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1431 def = &sym_zero; 1432 defobj = obj_main; 1433 } 1434 1435 if (def != NULL) { 1436 *defobj_out = defobj; 1437 /* Record the information in the cache to avoid subsequent lookups. */ 1438 if (cache != NULL) { 1439 cache[symnum].sym = def; 1440 cache[symnum].obj = defobj; 1441 } 1442 } else { 1443 if (refobj != &obj_rtld) 1444 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1445 } 1446 return def; 1447 } 1448 1449 /* 1450 * Return the search path from the ldconfig hints file, reading it if 1451 * necessary. Returns NULL if there are problems with the hints file, 1452 * or if the search path there is empty. 1453 */ 1454 static const char * 1455 gethints(void) 1456 { 1457 static char *hints; 1458 1459 if (hints == NULL) { 1460 int fd; 1461 struct elfhints_hdr hdr; 1462 char *p; 1463 1464 /* Keep from trying again in case the hints file is bad. */ 1465 hints = ""; 1466 1467 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1) 1468 return NULL; 1469 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1470 hdr.magic != ELFHINTS_MAGIC || 1471 hdr.version != 1) { 1472 close(fd); 1473 return NULL; 1474 } 1475 p = xmalloc(hdr.dirlistlen + 1); 1476 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1477 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) { 1478 free(p); 1479 close(fd); 1480 return NULL; 1481 } 1482 hints = p; 1483 close(fd); 1484 } 1485 return hints[0] != '\0' ? hints : NULL; 1486 } 1487 1488 static void 1489 init_dag(Obj_Entry *root) 1490 { 1491 const Needed_Entry *needed; 1492 const Objlist_Entry *elm; 1493 DoneList donelist; 1494 1495 if (root->dag_inited) 1496 return; 1497 donelist_init(&donelist); 1498 1499 /* Root object belongs to own DAG. */ 1500 objlist_push_tail(&root->dldags, root); 1501 objlist_push_tail(&root->dagmembers, root); 1502 donelist_check(&donelist, root); 1503 1504 /* 1505 * Add dependencies of root object to DAG in breadth order 1506 * by exploiting the fact that each new object get added 1507 * to the tail of the dagmembers list. 1508 */ 1509 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1510 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1511 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1512 continue; 1513 objlist_push_tail(&needed->obj->dldags, root); 1514 objlist_push_tail(&root->dagmembers, needed->obj); 1515 } 1516 } 1517 root->dag_inited = true; 1518 } 1519 1520 /* 1521 * Initialize the dynamic linker. The argument is the address at which 1522 * the dynamic linker has been mapped into memory. The primary task of 1523 * this function is to relocate the dynamic linker. 1524 */ 1525 static void 1526 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1527 { 1528 Obj_Entry objtmp; /* Temporary rtld object */ 1529 const Elf_Dyn *dyn_rpath; 1530 const Elf_Dyn *dyn_soname; 1531 1532 /* 1533 * Conjure up an Obj_Entry structure for the dynamic linker. 1534 * 1535 * The "path" member can't be initialized yet because string constants 1536 * cannot yet be accessed. Below we will set it correctly. 1537 */ 1538 memset(&objtmp, 0, sizeof(objtmp)); 1539 objtmp.path = NULL; 1540 objtmp.rtld = true; 1541 objtmp.mapbase = mapbase; 1542 #ifdef PIC 1543 objtmp.relocbase = mapbase; 1544 #endif 1545 if (RTLD_IS_DYNAMIC()) { 1546 objtmp.dynamic = rtld_dynamic(&objtmp); 1547 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname); 1548 assert(objtmp.needed == NULL); 1549 #if !defined(__mips__) 1550 /* MIPS has a bogus DT_TEXTREL. */ 1551 assert(!objtmp.textrel); 1552 #endif 1553 1554 /* 1555 * Temporarily put the dynamic linker entry into the object list, so 1556 * that symbols can be found. 1557 */ 1558 1559 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1560 } 1561 1562 /* Initialize the object list. */ 1563 obj_tail = &obj_list; 1564 1565 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1566 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1567 1568 if (aux_info[AT_PAGESZ] != NULL) 1569 pagesize = aux_info[AT_PAGESZ]->a_un.a_val; 1570 if (aux_info[AT_OSRELDATE] != NULL) 1571 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1572 1573 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname); 1574 1575 /* Replace the path with a dynamically allocated copy. */ 1576 obj_rtld.path = xstrdup(PATH_RTLD); 1577 1578 r_debug.r_brk = r_debug_state; 1579 r_debug.r_state = RT_CONSISTENT; 1580 } 1581 1582 /* 1583 * Add the init functions from a needed object list (and its recursive 1584 * needed objects) to "list". This is not used directly; it is a helper 1585 * function for initlist_add_objects(). The write lock must be held 1586 * when this function is called. 1587 */ 1588 static void 1589 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1590 { 1591 /* Recursively process the successor needed objects. */ 1592 if (needed->next != NULL) 1593 initlist_add_neededs(needed->next, list); 1594 1595 /* Process the current needed object. */ 1596 if (needed->obj != NULL) 1597 initlist_add_objects(needed->obj, &needed->obj->next, list); 1598 } 1599 1600 /* 1601 * Scan all of the DAGs rooted in the range of objects from "obj" to 1602 * "tail" and add their init functions to "list". This recurses over 1603 * the DAGs and ensure the proper init ordering such that each object's 1604 * needed libraries are initialized before the object itself. At the 1605 * same time, this function adds the objects to the global finalization 1606 * list "list_fini" in the opposite order. The write lock must be 1607 * held when this function is called. 1608 */ 1609 static void 1610 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1611 { 1612 1613 if (obj->init_scanned || obj->init_done) 1614 return; 1615 obj->init_scanned = true; 1616 1617 /* Recursively process the successor objects. */ 1618 if (&obj->next != tail) 1619 initlist_add_objects(obj->next, tail, list); 1620 1621 /* Recursively process the needed objects. */ 1622 if (obj->needed != NULL) 1623 initlist_add_neededs(obj->needed, list); 1624 if (obj->needed_filtees != NULL) 1625 initlist_add_neededs(obj->needed_filtees, list); 1626 if (obj->needed_aux_filtees != NULL) 1627 initlist_add_neededs(obj->needed_aux_filtees, list); 1628 1629 /* Add the object to the init list. */ 1630 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1631 obj->init_array != (Elf_Addr)NULL) 1632 objlist_push_tail(list, obj); 1633 1634 /* Add the object to the global fini list in the reverse order. */ 1635 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1636 && !obj->on_fini_list) { 1637 objlist_push_head(&list_fini, obj); 1638 obj->on_fini_list = true; 1639 } 1640 } 1641 1642 #ifndef FPTR_TARGET 1643 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1644 #endif 1645 1646 static void 1647 free_needed_filtees(Needed_Entry *n) 1648 { 1649 Needed_Entry *needed, *needed1; 1650 1651 for (needed = n; needed != NULL; needed = needed->next) { 1652 if (needed->obj != NULL) { 1653 dlclose(needed->obj); 1654 needed->obj = NULL; 1655 } 1656 } 1657 for (needed = n; needed != NULL; needed = needed1) { 1658 needed1 = needed->next; 1659 free(needed); 1660 } 1661 } 1662 1663 static void 1664 unload_filtees(Obj_Entry *obj) 1665 { 1666 1667 free_needed_filtees(obj->needed_filtees); 1668 obj->needed_filtees = NULL; 1669 free_needed_filtees(obj->needed_aux_filtees); 1670 obj->needed_aux_filtees = NULL; 1671 obj->filtees_loaded = false; 1672 } 1673 1674 static void 1675 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 1676 RtldLockState *lockstate) 1677 { 1678 1679 for (; needed != NULL; needed = needed->next) { 1680 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 1681 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 1682 RTLD_LOCAL, lockstate); 1683 } 1684 } 1685 1686 static void 1687 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 1688 { 1689 1690 lock_restart_for_upgrade(lockstate); 1691 if (!obj->filtees_loaded) { 1692 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 1693 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 1694 obj->filtees_loaded = true; 1695 } 1696 } 1697 1698 static int 1699 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 1700 { 1701 Obj_Entry *obj1; 1702 1703 for (; needed != NULL; needed = needed->next) { 1704 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 1705 flags & ~RTLD_LO_NOLOAD); 1706 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 1707 return (-1); 1708 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) { 1709 dbg("obj %s nodelete", obj1->path); 1710 init_dag(obj1); 1711 ref_dag(obj1); 1712 obj1->ref_nodel = true; 1713 } 1714 } 1715 return (0); 1716 } 1717 1718 /* 1719 * Given a shared object, traverse its list of needed objects, and load 1720 * each of them. Returns 0 on success. Generates an error message and 1721 * returns -1 on failure. 1722 */ 1723 static int 1724 load_needed_objects(Obj_Entry *first, int flags) 1725 { 1726 Obj_Entry *obj; 1727 1728 for (obj = first; obj != NULL; obj = obj->next) { 1729 if (process_needed(obj, obj->needed, flags) == -1) 1730 return (-1); 1731 } 1732 return (0); 1733 } 1734 1735 static int 1736 load_preload_objects(void) 1737 { 1738 char *p = ld_preload; 1739 static const char delim[] = " \t:;"; 1740 1741 if (p == NULL) 1742 return 0; 1743 1744 p += strspn(p, delim); 1745 while (*p != '\0') { 1746 size_t len = strcspn(p, delim); 1747 char savech; 1748 1749 savech = p[len]; 1750 p[len] = '\0'; 1751 if (load_object(p, -1, NULL, 0) == NULL) 1752 return -1; /* XXX - cleanup */ 1753 p[len] = savech; 1754 p += len; 1755 p += strspn(p, delim); 1756 } 1757 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 1758 return 0; 1759 } 1760 1761 static const char * 1762 printable_path(const char *path) 1763 { 1764 1765 return (path == NULL ? "<unknown>" : path); 1766 } 1767 1768 /* 1769 * Load a shared object into memory, if it is not already loaded. The 1770 * object may be specified by name or by user-supplied file descriptor 1771 * fd_u. In the later case, the fd_u descriptor is not closed, but its 1772 * duplicate is. 1773 * 1774 * Returns a pointer to the Obj_Entry for the object. Returns NULL 1775 * on failure. 1776 */ 1777 static Obj_Entry * 1778 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 1779 { 1780 Obj_Entry *obj; 1781 int fd; 1782 struct stat sb; 1783 char *path; 1784 1785 if (name != NULL) { 1786 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 1787 if (object_match_name(obj, name)) 1788 return (obj); 1789 } 1790 1791 path = find_library(name, refobj); 1792 if (path == NULL) 1793 return (NULL); 1794 } else 1795 path = NULL; 1796 1797 /* 1798 * If we didn't find a match by pathname, or the name is not 1799 * supplied, open the file and check again by device and inode. 1800 * This avoids false mismatches caused by multiple links or ".." 1801 * in pathnames. 1802 * 1803 * To avoid a race, we open the file and use fstat() rather than 1804 * using stat(). 1805 */ 1806 fd = -1; 1807 if (fd_u == -1) { 1808 if ((fd = open(path, O_RDONLY)) == -1) { 1809 _rtld_error("Cannot open \"%s\"", path); 1810 free(path); 1811 return (NULL); 1812 } 1813 } else { 1814 fd = dup(fd_u); 1815 if (fd == -1) { 1816 _rtld_error("Cannot dup fd"); 1817 free(path); 1818 return (NULL); 1819 } 1820 } 1821 if (fstat(fd, &sb) == -1) { 1822 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 1823 close(fd); 1824 free(path); 1825 return NULL; 1826 } 1827 for (obj = obj_list->next; obj != NULL; obj = obj->next) 1828 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 1829 break; 1830 if (obj != NULL && name != NULL) { 1831 object_add_name(obj, name); 1832 free(path); 1833 close(fd); 1834 return obj; 1835 } 1836 if (flags & RTLD_LO_NOLOAD) { 1837 free(path); 1838 close(fd); 1839 return (NULL); 1840 } 1841 1842 /* First use of this object, so we must map it in */ 1843 obj = do_load_object(fd, name, path, &sb, flags); 1844 if (obj == NULL) 1845 free(path); 1846 close(fd); 1847 1848 return obj; 1849 } 1850 1851 static Obj_Entry * 1852 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 1853 int flags) 1854 { 1855 Obj_Entry *obj; 1856 struct statfs fs; 1857 1858 /* 1859 * but first, make sure that environment variables haven't been 1860 * used to circumvent the noexec flag on a filesystem. 1861 */ 1862 if (dangerous_ld_env) { 1863 if (fstatfs(fd, &fs) != 0) { 1864 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 1865 return NULL; 1866 } 1867 if (fs.f_flags & MNT_NOEXEC) { 1868 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 1869 return NULL; 1870 } 1871 } 1872 dbg("loading \"%s\"", printable_path(path)); 1873 obj = map_object(fd, printable_path(path), sbp); 1874 if (obj == NULL) 1875 return NULL; 1876 1877 /* 1878 * If DT_SONAME is present in the object, digest_dynamic2 already 1879 * added it to the object names. 1880 */ 1881 if (name != NULL) 1882 object_add_name(obj, name); 1883 obj->path = path; 1884 digest_dynamic(obj, 0); 1885 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 1886 RTLD_LO_DLOPEN) { 1887 dbg("refusing to load non-loadable \"%s\"", obj->path); 1888 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 1889 munmap(obj->mapbase, obj->mapsize); 1890 obj_free(obj); 1891 return (NULL); 1892 } 1893 1894 *obj_tail = obj; 1895 obj_tail = &obj->next; 1896 obj_count++; 1897 obj_loads++; 1898 linkmap_add(obj); /* for GDB & dlinfo() */ 1899 max_stack_flags |= obj->stack_flags; 1900 1901 dbg(" %p .. %p: %s", obj->mapbase, 1902 obj->mapbase + obj->mapsize - 1, obj->path); 1903 if (obj->textrel) 1904 dbg(" WARNING: %s has impure text", obj->path); 1905 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 1906 obj->path); 1907 1908 return obj; 1909 } 1910 1911 static Obj_Entry * 1912 obj_from_addr(const void *addr) 1913 { 1914 Obj_Entry *obj; 1915 1916 for (obj = obj_list; obj != NULL; obj = obj->next) { 1917 if (addr < (void *) obj->mapbase) 1918 continue; 1919 if (addr < (void *) (obj->mapbase + obj->mapsize)) 1920 return obj; 1921 } 1922 return NULL; 1923 } 1924 1925 static void 1926 preinit_main(void) 1927 { 1928 Elf_Addr *preinit_addr; 1929 int index; 1930 1931 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 1932 if (preinit_addr == NULL) 1933 return; 1934 1935 for (index = 0; index < obj_main->preinit_array_num; index++) { 1936 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 1937 dbg("calling preinit function for %s at %p", obj_main->path, 1938 (void *)preinit_addr[index]); 1939 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 1940 0, 0, obj_main->path); 1941 call_init_pointer(obj_main, preinit_addr[index]); 1942 } 1943 } 1944 } 1945 1946 /* 1947 * Call the finalization functions for each of the objects in "list" 1948 * belonging to the DAG of "root" and referenced once. If NULL "root" 1949 * is specified, every finalization function will be called regardless 1950 * of the reference count and the list elements won't be freed. All of 1951 * the objects are expected to have non-NULL fini functions. 1952 */ 1953 static void 1954 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 1955 { 1956 Objlist_Entry *elm; 1957 char *saved_msg; 1958 Elf_Addr *fini_addr; 1959 int index; 1960 1961 assert(root == NULL || root->refcount == 1); 1962 1963 /* 1964 * Preserve the current error message since a fini function might 1965 * call into the dynamic linker and overwrite it. 1966 */ 1967 saved_msg = errmsg_save(); 1968 do { 1969 STAILQ_FOREACH(elm, list, link) { 1970 if (root != NULL && (elm->obj->refcount != 1 || 1971 objlist_find(&root->dagmembers, elm->obj) == NULL)) 1972 continue; 1973 /* Remove object from fini list to prevent recursive invocation. */ 1974 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 1975 /* 1976 * XXX: If a dlopen() call references an object while the 1977 * fini function is in progress, we might end up trying to 1978 * unload the referenced object in dlclose() or the object 1979 * won't be unloaded although its fini function has been 1980 * called. 1981 */ 1982 lock_release(rtld_bind_lock, lockstate); 1983 1984 /* 1985 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 1986 * When this happens, DT_FINI_ARRAY is processed first. 1987 */ 1988 fini_addr = (Elf_Addr *)elm->obj->fini_array; 1989 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 1990 for (index = elm->obj->fini_array_num - 1; index >= 0; 1991 index--) { 1992 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 1993 dbg("calling fini function for %s at %p", 1994 elm->obj->path, (void *)fini_addr[index]); 1995 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 1996 (void *)fini_addr[index], 0, 0, elm->obj->path); 1997 call_initfini_pointer(elm->obj, fini_addr[index]); 1998 } 1999 } 2000 } 2001 if (elm->obj->fini != (Elf_Addr)NULL) { 2002 dbg("calling fini function for %s at %p", elm->obj->path, 2003 (void *)elm->obj->fini); 2004 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2005 0, 0, elm->obj->path); 2006 call_initfini_pointer(elm->obj, elm->obj->fini); 2007 } 2008 wlock_acquire(rtld_bind_lock, lockstate); 2009 /* No need to free anything if process is going down. */ 2010 if (root != NULL) 2011 free(elm); 2012 /* 2013 * We must restart the list traversal after every fini call 2014 * because a dlclose() call from the fini function or from 2015 * another thread might have modified the reference counts. 2016 */ 2017 break; 2018 } 2019 } while (elm != NULL); 2020 errmsg_restore(saved_msg); 2021 } 2022 2023 /* 2024 * Call the initialization functions for each of the objects in 2025 * "list". All of the objects are expected to have non-NULL init 2026 * functions. 2027 */ 2028 static void 2029 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2030 { 2031 Objlist_Entry *elm; 2032 Obj_Entry *obj; 2033 char *saved_msg; 2034 Elf_Addr *init_addr; 2035 int index; 2036 2037 /* 2038 * Clean init_scanned flag so that objects can be rechecked and 2039 * possibly initialized earlier if any of vectors called below 2040 * cause the change by using dlopen. 2041 */ 2042 for (obj = obj_list; obj != NULL; obj = obj->next) 2043 obj->init_scanned = false; 2044 2045 /* 2046 * Preserve the current error message since an init function might 2047 * call into the dynamic linker and overwrite it. 2048 */ 2049 saved_msg = errmsg_save(); 2050 STAILQ_FOREACH(elm, list, link) { 2051 if (elm->obj->init_done) /* Initialized early. */ 2052 continue; 2053 /* 2054 * Race: other thread might try to use this object before current 2055 * one completes the initilization. Not much can be done here 2056 * without better locking. 2057 */ 2058 elm->obj->init_done = true; 2059 lock_release(rtld_bind_lock, lockstate); 2060 2061 /* 2062 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2063 * When this happens, DT_INIT is processed first. 2064 */ 2065 if (elm->obj->init != (Elf_Addr)NULL) { 2066 dbg("calling init function for %s at %p", elm->obj->path, 2067 (void *)elm->obj->init); 2068 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2069 0, 0, elm->obj->path); 2070 call_initfini_pointer(elm->obj, elm->obj->init); 2071 } 2072 init_addr = (Elf_Addr *)elm->obj->init_array; 2073 if (init_addr != NULL) { 2074 for (index = 0; index < elm->obj->init_array_num; index++) { 2075 if (init_addr[index] != 0 && init_addr[index] != 1) { 2076 dbg("calling init function for %s at %p", elm->obj->path, 2077 (void *)init_addr[index]); 2078 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2079 (void *)init_addr[index], 0, 0, elm->obj->path); 2080 call_init_pointer(elm->obj, init_addr[index]); 2081 } 2082 } 2083 } 2084 wlock_acquire(rtld_bind_lock, lockstate); 2085 } 2086 errmsg_restore(saved_msg); 2087 } 2088 2089 static void 2090 objlist_clear(Objlist *list) 2091 { 2092 Objlist_Entry *elm; 2093 2094 while (!STAILQ_EMPTY(list)) { 2095 elm = STAILQ_FIRST(list); 2096 STAILQ_REMOVE_HEAD(list, link); 2097 free(elm); 2098 } 2099 } 2100 2101 static Objlist_Entry * 2102 objlist_find(Objlist *list, const Obj_Entry *obj) 2103 { 2104 Objlist_Entry *elm; 2105 2106 STAILQ_FOREACH(elm, list, link) 2107 if (elm->obj == obj) 2108 return elm; 2109 return NULL; 2110 } 2111 2112 static void 2113 objlist_init(Objlist *list) 2114 { 2115 STAILQ_INIT(list); 2116 } 2117 2118 static void 2119 objlist_push_head(Objlist *list, Obj_Entry *obj) 2120 { 2121 Objlist_Entry *elm; 2122 2123 elm = NEW(Objlist_Entry); 2124 elm->obj = obj; 2125 STAILQ_INSERT_HEAD(list, elm, link); 2126 } 2127 2128 static void 2129 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2130 { 2131 Objlist_Entry *elm; 2132 2133 elm = NEW(Objlist_Entry); 2134 elm->obj = obj; 2135 STAILQ_INSERT_TAIL(list, elm, link); 2136 } 2137 2138 static void 2139 objlist_remove(Objlist *list, Obj_Entry *obj) 2140 { 2141 Objlist_Entry *elm; 2142 2143 if ((elm = objlist_find(list, obj)) != NULL) { 2144 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2145 free(elm); 2146 } 2147 } 2148 2149 /* 2150 * Relocate newly-loaded shared objects. The argument is a pointer to 2151 * the Obj_Entry for the first such object. All objects from the first 2152 * to the end of the list of objects are relocated. Returns 0 on success, 2153 * or -1 on failure. 2154 */ 2155 static int 2156 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2157 int flags, RtldLockState *lockstate) 2158 { 2159 Obj_Entry *obj; 2160 2161 for (obj = first; obj != NULL; obj = obj->next) { 2162 if (obj->relocated) 2163 continue; 2164 obj->relocated = true; 2165 if (obj != rtldobj) 2166 dbg("relocating \"%s\"", obj->path); 2167 2168 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || 2169 obj->symtab == NULL || obj->strtab == NULL) { 2170 _rtld_error("%s: Shared object has no run-time symbol table", 2171 obj->path); 2172 return -1; 2173 } 2174 2175 if (obj->textrel) { 2176 /* There are relocations to the write-protected text segment. */ 2177 if (mprotect(obj->mapbase, obj->textsize, 2178 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2179 _rtld_error("%s: Cannot write-enable text segment: %s", 2180 obj->path, rtld_strerror(errno)); 2181 return -1; 2182 } 2183 } 2184 2185 /* Process the non-PLT relocations. */ 2186 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2187 return -1; 2188 2189 if (obj->textrel) { /* Re-protected the text segment. */ 2190 if (mprotect(obj->mapbase, obj->textsize, 2191 PROT_READ|PROT_EXEC) == -1) { 2192 _rtld_error("%s: Cannot write-protect text segment: %s", 2193 obj->path, rtld_strerror(errno)); 2194 return -1; 2195 } 2196 } 2197 2198 2199 /* Set the special PLT or GOT entries. */ 2200 init_pltgot(obj); 2201 2202 /* Process the PLT relocations. */ 2203 if (reloc_plt(obj) == -1) 2204 return -1; 2205 /* Relocate the jump slots if we are doing immediate binding. */ 2206 if (obj->bind_now || bind_now) 2207 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2208 return -1; 2209 2210 if (obj->relro_size > 0) { 2211 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2212 _rtld_error("%s: Cannot enforce relro protection: %s", 2213 obj->path, rtld_strerror(errno)); 2214 return -1; 2215 } 2216 } 2217 2218 /* 2219 * Set up the magic number and version in the Obj_Entry. These 2220 * were checked in the crt1.o from the original ElfKit, so we 2221 * set them for backward compatibility. 2222 */ 2223 obj->magic = RTLD_MAGIC; 2224 obj->version = RTLD_VERSION; 2225 } 2226 2227 return (0); 2228 } 2229 2230 /* 2231 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2232 * referencing STT_GNU_IFUNC symbols is postponed till the other 2233 * relocations are done. The indirect functions specified as 2234 * ifunc are allowed to call other symbols, so we need to have 2235 * objects relocated before asking for resolution from indirects. 2236 * 2237 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2238 * instead of the usual lazy handling of PLT slots. It is 2239 * consistent with how GNU does it. 2240 */ 2241 static int 2242 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2243 RtldLockState *lockstate) 2244 { 2245 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2246 return (-1); 2247 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2248 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2249 return (-1); 2250 return (0); 2251 } 2252 2253 static int 2254 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2255 RtldLockState *lockstate) 2256 { 2257 Obj_Entry *obj; 2258 2259 for (obj = first; obj != NULL; obj = obj->next) { 2260 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2261 return (-1); 2262 } 2263 return (0); 2264 } 2265 2266 static int 2267 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2268 RtldLockState *lockstate) 2269 { 2270 Objlist_Entry *elm; 2271 2272 STAILQ_FOREACH(elm, list, link) { 2273 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2274 lockstate) == -1) 2275 return (-1); 2276 } 2277 return (0); 2278 } 2279 2280 /* 2281 * Cleanup procedure. It will be called (by the atexit mechanism) just 2282 * before the process exits. 2283 */ 2284 static void 2285 rtld_exit(void) 2286 { 2287 RtldLockState lockstate; 2288 2289 wlock_acquire(rtld_bind_lock, &lockstate); 2290 dbg("rtld_exit()"); 2291 objlist_call_fini(&list_fini, NULL, &lockstate); 2292 /* No need to remove the items from the list, since we are exiting. */ 2293 if (!libmap_disable) 2294 lm_fini(); 2295 lock_release(rtld_bind_lock, &lockstate); 2296 } 2297 2298 static void * 2299 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2300 { 2301 #ifdef COMPAT_32BIT 2302 const char *trans; 2303 #endif 2304 if (path == NULL) 2305 return (NULL); 2306 2307 path += strspn(path, ":;"); 2308 while (*path != '\0') { 2309 size_t len; 2310 char *res; 2311 2312 len = strcspn(path, ":;"); 2313 #ifdef COMPAT_32BIT 2314 trans = lm_findn(NULL, path, len); 2315 if (trans) 2316 res = callback(trans, strlen(trans), arg); 2317 else 2318 #endif 2319 res = callback(path, len, arg); 2320 2321 if (res != NULL) 2322 return (res); 2323 2324 path += len; 2325 path += strspn(path, ":;"); 2326 } 2327 2328 return (NULL); 2329 } 2330 2331 struct try_library_args { 2332 const char *name; 2333 size_t namelen; 2334 char *buffer; 2335 size_t buflen; 2336 }; 2337 2338 static void * 2339 try_library_path(const char *dir, size_t dirlen, void *param) 2340 { 2341 struct try_library_args *arg; 2342 2343 arg = param; 2344 if (*dir == '/' || trust) { 2345 char *pathname; 2346 2347 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2348 return (NULL); 2349 2350 pathname = arg->buffer; 2351 strncpy(pathname, dir, dirlen); 2352 pathname[dirlen] = '/'; 2353 strcpy(pathname + dirlen + 1, arg->name); 2354 2355 dbg(" Trying \"%s\"", pathname); 2356 if (access(pathname, F_OK) == 0) { /* We found it */ 2357 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2358 strcpy(pathname, arg->buffer); 2359 return (pathname); 2360 } 2361 } 2362 return (NULL); 2363 } 2364 2365 static char * 2366 search_library_path(const char *name, const char *path) 2367 { 2368 char *p; 2369 struct try_library_args arg; 2370 2371 if (path == NULL) 2372 return NULL; 2373 2374 arg.name = name; 2375 arg.namelen = strlen(name); 2376 arg.buffer = xmalloc(PATH_MAX); 2377 arg.buflen = PATH_MAX; 2378 2379 p = path_enumerate(path, try_library_path, &arg); 2380 2381 free(arg.buffer); 2382 2383 return (p); 2384 } 2385 2386 int 2387 dlclose(void *handle) 2388 { 2389 Obj_Entry *root; 2390 RtldLockState lockstate; 2391 2392 wlock_acquire(rtld_bind_lock, &lockstate); 2393 root = dlcheck(handle); 2394 if (root == NULL) { 2395 lock_release(rtld_bind_lock, &lockstate); 2396 return -1; 2397 } 2398 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2399 root->path); 2400 2401 /* Unreference the object and its dependencies. */ 2402 root->dl_refcount--; 2403 2404 if (root->refcount == 1) { 2405 /* 2406 * The object will be no longer referenced, so we must unload it. 2407 * First, call the fini functions. 2408 */ 2409 objlist_call_fini(&list_fini, root, &lockstate); 2410 2411 unref_dag(root); 2412 2413 /* Finish cleaning up the newly-unreferenced objects. */ 2414 GDB_STATE(RT_DELETE,&root->linkmap); 2415 unload_object(root); 2416 GDB_STATE(RT_CONSISTENT,NULL); 2417 } else 2418 unref_dag(root); 2419 2420 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2421 lock_release(rtld_bind_lock, &lockstate); 2422 return 0; 2423 } 2424 2425 char * 2426 dlerror(void) 2427 { 2428 char *msg = error_message; 2429 error_message = NULL; 2430 return msg; 2431 } 2432 2433 /* 2434 * This function is deprecated and has no effect. 2435 */ 2436 void 2437 dllockinit(void *context, 2438 void *(*lock_create)(void *context), 2439 void (*rlock_acquire)(void *lock), 2440 void (*wlock_acquire)(void *lock), 2441 void (*lock_release)(void *lock), 2442 void (*lock_destroy)(void *lock), 2443 void (*context_destroy)(void *context)) 2444 { 2445 static void *cur_context; 2446 static void (*cur_context_destroy)(void *); 2447 2448 /* Just destroy the context from the previous call, if necessary. */ 2449 if (cur_context_destroy != NULL) 2450 cur_context_destroy(cur_context); 2451 cur_context = context; 2452 cur_context_destroy = context_destroy; 2453 } 2454 2455 void * 2456 dlopen(const char *name, int mode) 2457 { 2458 2459 return (rtld_dlopen(name, -1, mode)); 2460 } 2461 2462 void * 2463 fdlopen(int fd, int mode) 2464 { 2465 2466 return (rtld_dlopen(NULL, fd, mode)); 2467 } 2468 2469 static void * 2470 rtld_dlopen(const char *name, int fd, int mode) 2471 { 2472 RtldLockState lockstate; 2473 int lo_flags; 2474 2475 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2476 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2477 if (ld_tracing != NULL) { 2478 rlock_acquire(rtld_bind_lock, &lockstate); 2479 if (sigsetjmp(lockstate.env, 0) != 0) 2480 lock_upgrade(rtld_bind_lock, &lockstate); 2481 environ = (char **)*get_program_var_addr("environ", &lockstate); 2482 lock_release(rtld_bind_lock, &lockstate); 2483 } 2484 lo_flags = RTLD_LO_DLOPEN; 2485 if (mode & RTLD_NODELETE) 2486 lo_flags |= RTLD_LO_NODELETE; 2487 if (mode & RTLD_NOLOAD) 2488 lo_flags |= RTLD_LO_NOLOAD; 2489 if (ld_tracing != NULL) 2490 lo_flags |= RTLD_LO_TRACE; 2491 2492 return (dlopen_object(name, fd, obj_main, lo_flags, 2493 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2494 } 2495 2496 static void 2497 dlopen_cleanup(Obj_Entry *obj) 2498 { 2499 2500 obj->dl_refcount--; 2501 unref_dag(obj); 2502 if (obj->refcount == 0) 2503 unload_object(obj); 2504 } 2505 2506 static Obj_Entry * 2507 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2508 int mode, RtldLockState *lockstate) 2509 { 2510 Obj_Entry **old_obj_tail; 2511 Obj_Entry *obj; 2512 Objlist initlist; 2513 RtldLockState mlockstate; 2514 int result; 2515 2516 objlist_init(&initlist); 2517 2518 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2519 wlock_acquire(rtld_bind_lock, &mlockstate); 2520 lockstate = &mlockstate; 2521 } 2522 GDB_STATE(RT_ADD,NULL); 2523 2524 old_obj_tail = obj_tail; 2525 obj = NULL; 2526 if (name == NULL && fd == -1) { 2527 obj = obj_main; 2528 obj->refcount++; 2529 } else { 2530 obj = load_object(name, fd, refobj, lo_flags); 2531 } 2532 2533 if (obj) { 2534 obj->dl_refcount++; 2535 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2536 objlist_push_tail(&list_global, obj); 2537 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2538 assert(*old_obj_tail == obj); 2539 result = load_needed_objects(obj, 2540 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2541 init_dag(obj); 2542 ref_dag(obj); 2543 if (result != -1) 2544 result = rtld_verify_versions(&obj->dagmembers); 2545 if (result != -1 && ld_tracing) 2546 goto trace; 2547 if (result == -1 || (relocate_objects(obj, 2548 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2549 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2550 lockstate)) == -1) { 2551 dlopen_cleanup(obj); 2552 obj = NULL; 2553 } else if (lo_flags & RTLD_LO_EARLY) { 2554 /* 2555 * Do not call the init functions for early loaded 2556 * filtees. The image is still not initialized enough 2557 * for them to work. 2558 * 2559 * Our object is found by the global object list and 2560 * will be ordered among all init calls done right 2561 * before transferring control to main. 2562 */ 2563 } else { 2564 /* Make list of init functions to call. */ 2565 initlist_add_objects(obj, &obj->next, &initlist); 2566 } 2567 } else { 2568 2569 /* 2570 * Bump the reference counts for objects on this DAG. If 2571 * this is the first dlopen() call for the object that was 2572 * already loaded as a dependency, initialize the dag 2573 * starting at it. 2574 */ 2575 init_dag(obj); 2576 ref_dag(obj); 2577 2578 if ((lo_flags & RTLD_LO_TRACE) != 0) 2579 goto trace; 2580 } 2581 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2582 obj->z_nodelete) && !obj->ref_nodel) { 2583 dbg("obj %s nodelete", obj->path); 2584 ref_dag(obj); 2585 obj->z_nodelete = obj->ref_nodel = true; 2586 } 2587 } 2588 2589 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2590 name); 2591 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2592 2593 if (!(lo_flags & RTLD_LO_EARLY)) { 2594 map_stacks_exec(lockstate); 2595 } 2596 2597 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 2598 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2599 lockstate) == -1) { 2600 objlist_clear(&initlist); 2601 dlopen_cleanup(obj); 2602 if (lockstate == &mlockstate) 2603 lock_release(rtld_bind_lock, lockstate); 2604 return (NULL); 2605 } 2606 2607 if (!(lo_flags & RTLD_LO_EARLY)) { 2608 /* Call the init functions. */ 2609 objlist_call_init(&initlist, lockstate); 2610 } 2611 objlist_clear(&initlist); 2612 if (lockstate == &mlockstate) 2613 lock_release(rtld_bind_lock, lockstate); 2614 return obj; 2615 trace: 2616 trace_loaded_objects(obj); 2617 if (lockstate == &mlockstate) 2618 lock_release(rtld_bind_lock, lockstate); 2619 exit(0); 2620 } 2621 2622 static void * 2623 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 2624 int flags) 2625 { 2626 DoneList donelist; 2627 const Obj_Entry *obj, *defobj; 2628 const Elf_Sym *def; 2629 SymLook req; 2630 RtldLockState lockstate; 2631 #ifndef __ia64__ 2632 tls_index ti; 2633 #endif 2634 int res; 2635 2636 def = NULL; 2637 defobj = NULL; 2638 symlook_init(&req, name); 2639 req.ventry = ve; 2640 req.flags = flags | SYMLOOK_IN_PLT; 2641 req.lockstate = &lockstate; 2642 2643 rlock_acquire(rtld_bind_lock, &lockstate); 2644 if (sigsetjmp(lockstate.env, 0) != 0) 2645 lock_upgrade(rtld_bind_lock, &lockstate); 2646 if (handle == NULL || handle == RTLD_NEXT || 2647 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 2648 2649 if ((obj = obj_from_addr(retaddr)) == NULL) { 2650 _rtld_error("Cannot determine caller's shared object"); 2651 lock_release(rtld_bind_lock, &lockstate); 2652 return NULL; 2653 } 2654 if (handle == NULL) { /* Just the caller's shared object. */ 2655 res = symlook_obj(&req, obj); 2656 if (res == 0) { 2657 def = req.sym_out; 2658 defobj = req.defobj_out; 2659 } 2660 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 2661 handle == RTLD_SELF) { /* ... caller included */ 2662 if (handle == RTLD_NEXT) 2663 obj = obj->next; 2664 for (; obj != NULL; obj = obj->next) { 2665 res = symlook_obj(&req, obj); 2666 if (res == 0) { 2667 if (def == NULL || 2668 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 2669 def = req.sym_out; 2670 defobj = req.defobj_out; 2671 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 2672 break; 2673 } 2674 } 2675 } 2676 /* 2677 * Search the dynamic linker itself, and possibly resolve the 2678 * symbol from there. This is how the application links to 2679 * dynamic linker services such as dlopen. 2680 */ 2681 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2682 res = symlook_obj(&req, &obj_rtld); 2683 if (res == 0) { 2684 def = req.sym_out; 2685 defobj = req.defobj_out; 2686 } 2687 } 2688 } else { 2689 assert(handle == RTLD_DEFAULT); 2690 res = symlook_default(&req, obj); 2691 if (res == 0) { 2692 defobj = req.defobj_out; 2693 def = req.sym_out; 2694 } 2695 } 2696 } else { 2697 if ((obj = dlcheck(handle)) == NULL) { 2698 lock_release(rtld_bind_lock, &lockstate); 2699 return NULL; 2700 } 2701 2702 donelist_init(&donelist); 2703 if (obj->mainprog) { 2704 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 2705 res = symlook_global(&req, &donelist); 2706 if (res == 0) { 2707 def = req.sym_out; 2708 defobj = req.defobj_out; 2709 } 2710 /* 2711 * Search the dynamic linker itself, and possibly resolve the 2712 * symbol from there. This is how the application links to 2713 * dynamic linker services such as dlopen. 2714 */ 2715 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 2716 res = symlook_obj(&req, &obj_rtld); 2717 if (res == 0) { 2718 def = req.sym_out; 2719 defobj = req.defobj_out; 2720 } 2721 } 2722 } 2723 else { 2724 /* Search the whole DAG rooted at the given object. */ 2725 res = symlook_list(&req, &obj->dagmembers, &donelist); 2726 if (res == 0) { 2727 def = req.sym_out; 2728 defobj = req.defobj_out; 2729 } 2730 } 2731 } 2732 2733 if (def != NULL) { 2734 lock_release(rtld_bind_lock, &lockstate); 2735 2736 /* 2737 * The value required by the caller is derived from the value 2738 * of the symbol. For the ia64 architecture, we need to 2739 * construct a function descriptor which the caller can use to 2740 * call the function with the right 'gp' value. For other 2741 * architectures and for non-functions, the value is simply 2742 * the relocated value of the symbol. 2743 */ 2744 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 2745 return (make_function_pointer(def, defobj)); 2746 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 2747 return (rtld_resolve_ifunc(defobj, def)); 2748 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 2749 #ifdef __ia64__ 2750 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 2751 #else 2752 ti.ti_module = defobj->tlsindex; 2753 ti.ti_offset = def->st_value; 2754 return (__tls_get_addr(&ti)); 2755 #endif 2756 } else 2757 return (defobj->relocbase + def->st_value); 2758 } 2759 2760 _rtld_error("Undefined symbol \"%s\"", name); 2761 lock_release(rtld_bind_lock, &lockstate); 2762 return NULL; 2763 } 2764 2765 void * 2766 dlsym(void *handle, const char *name) 2767 { 2768 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 2769 SYMLOOK_DLSYM); 2770 } 2771 2772 dlfunc_t 2773 dlfunc(void *handle, const char *name) 2774 { 2775 union { 2776 void *d; 2777 dlfunc_t f; 2778 } rv; 2779 2780 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 2781 SYMLOOK_DLSYM); 2782 return (rv.f); 2783 } 2784 2785 void * 2786 dlvsym(void *handle, const char *name, const char *version) 2787 { 2788 Ver_Entry ventry; 2789 2790 ventry.name = version; 2791 ventry.file = NULL; 2792 ventry.hash = elf_hash(version); 2793 ventry.flags= 0; 2794 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 2795 SYMLOOK_DLSYM); 2796 } 2797 2798 int 2799 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 2800 { 2801 const Obj_Entry *obj; 2802 RtldLockState lockstate; 2803 2804 rlock_acquire(rtld_bind_lock, &lockstate); 2805 obj = obj_from_addr(addr); 2806 if (obj == NULL) { 2807 _rtld_error("No shared object contains address"); 2808 lock_release(rtld_bind_lock, &lockstate); 2809 return (0); 2810 } 2811 rtld_fill_dl_phdr_info(obj, phdr_info); 2812 lock_release(rtld_bind_lock, &lockstate); 2813 return (1); 2814 } 2815 2816 int 2817 dladdr(const void *addr, Dl_info *info) 2818 { 2819 const Obj_Entry *obj; 2820 const Elf_Sym *def; 2821 void *symbol_addr; 2822 unsigned long symoffset; 2823 RtldLockState lockstate; 2824 2825 rlock_acquire(rtld_bind_lock, &lockstate); 2826 obj = obj_from_addr(addr); 2827 if (obj == NULL) { 2828 _rtld_error("No shared object contains address"); 2829 lock_release(rtld_bind_lock, &lockstate); 2830 return 0; 2831 } 2832 info->dli_fname = obj->path; 2833 info->dli_fbase = obj->mapbase; 2834 info->dli_saddr = (void *)0; 2835 info->dli_sname = NULL; 2836 2837 /* 2838 * Walk the symbol list looking for the symbol whose address is 2839 * closest to the address sent in. 2840 */ 2841 for (symoffset = 0; symoffset < obj->nchains; symoffset++) { 2842 def = obj->symtab + symoffset; 2843 2844 /* 2845 * For skip the symbol if st_shndx is either SHN_UNDEF or 2846 * SHN_COMMON. 2847 */ 2848 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 2849 continue; 2850 2851 /* 2852 * If the symbol is greater than the specified address, or if it 2853 * is further away from addr than the current nearest symbol, 2854 * then reject it. 2855 */ 2856 symbol_addr = obj->relocbase + def->st_value; 2857 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 2858 continue; 2859 2860 /* Update our idea of the nearest symbol. */ 2861 info->dli_sname = obj->strtab + def->st_name; 2862 info->dli_saddr = symbol_addr; 2863 2864 /* Exact match? */ 2865 if (info->dli_saddr == addr) 2866 break; 2867 } 2868 lock_release(rtld_bind_lock, &lockstate); 2869 return 1; 2870 } 2871 2872 int 2873 dlinfo(void *handle, int request, void *p) 2874 { 2875 const Obj_Entry *obj; 2876 RtldLockState lockstate; 2877 int error; 2878 2879 rlock_acquire(rtld_bind_lock, &lockstate); 2880 2881 if (handle == NULL || handle == RTLD_SELF) { 2882 void *retaddr; 2883 2884 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 2885 if ((obj = obj_from_addr(retaddr)) == NULL) 2886 _rtld_error("Cannot determine caller's shared object"); 2887 } else 2888 obj = dlcheck(handle); 2889 2890 if (obj == NULL) { 2891 lock_release(rtld_bind_lock, &lockstate); 2892 return (-1); 2893 } 2894 2895 error = 0; 2896 switch (request) { 2897 case RTLD_DI_LINKMAP: 2898 *((struct link_map const **)p) = &obj->linkmap; 2899 break; 2900 case RTLD_DI_ORIGIN: 2901 error = rtld_dirname(obj->path, p); 2902 break; 2903 2904 case RTLD_DI_SERINFOSIZE: 2905 case RTLD_DI_SERINFO: 2906 error = do_search_info(obj, request, (struct dl_serinfo *)p); 2907 break; 2908 2909 default: 2910 _rtld_error("Invalid request %d passed to dlinfo()", request); 2911 error = -1; 2912 } 2913 2914 lock_release(rtld_bind_lock, &lockstate); 2915 2916 return (error); 2917 } 2918 2919 static void 2920 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 2921 { 2922 2923 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 2924 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ? 2925 STAILQ_FIRST(&obj->names)->name : obj->path; 2926 phdr_info->dlpi_phdr = obj->phdr; 2927 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 2928 phdr_info->dlpi_tls_modid = obj->tlsindex; 2929 phdr_info->dlpi_tls_data = obj->tlsinit; 2930 phdr_info->dlpi_adds = obj_loads; 2931 phdr_info->dlpi_subs = obj_loads - obj_count; 2932 } 2933 2934 int 2935 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 2936 { 2937 struct dl_phdr_info phdr_info; 2938 const Obj_Entry *obj; 2939 RtldLockState bind_lockstate, phdr_lockstate; 2940 int error; 2941 2942 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 2943 rlock_acquire(rtld_bind_lock, &bind_lockstate); 2944 2945 error = 0; 2946 2947 for (obj = obj_list; obj != NULL; obj = obj->next) { 2948 rtld_fill_dl_phdr_info(obj, &phdr_info); 2949 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 2950 break; 2951 2952 } 2953 lock_release(rtld_bind_lock, &bind_lockstate); 2954 lock_release(rtld_phdr_lock, &phdr_lockstate); 2955 2956 return (error); 2957 } 2958 2959 struct fill_search_info_args { 2960 int request; 2961 unsigned int flags; 2962 Dl_serinfo *serinfo; 2963 Dl_serpath *serpath; 2964 char *strspace; 2965 }; 2966 2967 static void * 2968 fill_search_info(const char *dir, size_t dirlen, void *param) 2969 { 2970 struct fill_search_info_args *arg; 2971 2972 arg = param; 2973 2974 if (arg->request == RTLD_DI_SERINFOSIZE) { 2975 arg->serinfo->dls_cnt ++; 2976 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1; 2977 } else { 2978 struct dl_serpath *s_entry; 2979 2980 s_entry = arg->serpath; 2981 s_entry->dls_name = arg->strspace; 2982 s_entry->dls_flags = arg->flags; 2983 2984 strncpy(arg->strspace, dir, dirlen); 2985 arg->strspace[dirlen] = '\0'; 2986 2987 arg->strspace += dirlen + 1; 2988 arg->serpath++; 2989 } 2990 2991 return (NULL); 2992 } 2993 2994 static int 2995 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 2996 { 2997 struct dl_serinfo _info; 2998 struct fill_search_info_args args; 2999 3000 args.request = RTLD_DI_SERINFOSIZE; 3001 args.serinfo = &_info; 3002 3003 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3004 _info.dls_cnt = 0; 3005 3006 path_enumerate(ld_library_path, fill_search_info, &args); 3007 path_enumerate(obj->rpath, fill_search_info, &args); 3008 path_enumerate(gethints(), fill_search_info, &args); 3009 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3010 3011 3012 if (request == RTLD_DI_SERINFOSIZE) { 3013 info->dls_size = _info.dls_size; 3014 info->dls_cnt = _info.dls_cnt; 3015 return (0); 3016 } 3017 3018 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3019 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3020 return (-1); 3021 } 3022 3023 args.request = RTLD_DI_SERINFO; 3024 args.serinfo = info; 3025 args.serpath = &info->dls_serpath[0]; 3026 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3027 3028 args.flags = LA_SER_LIBPATH; 3029 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3030 return (-1); 3031 3032 args.flags = LA_SER_RUNPATH; 3033 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3034 return (-1); 3035 3036 args.flags = LA_SER_CONFIG; 3037 if (path_enumerate(gethints(), fill_search_info, &args) != NULL) 3038 return (-1); 3039 3040 args.flags = LA_SER_DEFAULT; 3041 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3042 return (-1); 3043 return (0); 3044 } 3045 3046 static int 3047 rtld_dirname(const char *path, char *bname) 3048 { 3049 const char *endp; 3050 3051 /* Empty or NULL string gets treated as "." */ 3052 if (path == NULL || *path == '\0') { 3053 bname[0] = '.'; 3054 bname[1] = '\0'; 3055 return (0); 3056 } 3057 3058 /* Strip trailing slashes */ 3059 endp = path + strlen(path) - 1; 3060 while (endp > path && *endp == '/') 3061 endp--; 3062 3063 /* Find the start of the dir */ 3064 while (endp > path && *endp != '/') 3065 endp--; 3066 3067 /* Either the dir is "/" or there are no slashes */ 3068 if (endp == path) { 3069 bname[0] = *endp == '/' ? '/' : '.'; 3070 bname[1] = '\0'; 3071 return (0); 3072 } else { 3073 do { 3074 endp--; 3075 } while (endp > path && *endp == '/'); 3076 } 3077 3078 if (endp - path + 2 > PATH_MAX) 3079 { 3080 _rtld_error("Filename is too long: %s", path); 3081 return(-1); 3082 } 3083 3084 strncpy(bname, path, endp - path + 1); 3085 bname[endp - path + 1] = '\0'; 3086 return (0); 3087 } 3088 3089 static int 3090 rtld_dirname_abs(const char *path, char *base) 3091 { 3092 char base_rel[PATH_MAX]; 3093 3094 if (rtld_dirname(path, base) == -1) 3095 return (-1); 3096 if (base[0] == '/') 3097 return (0); 3098 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3099 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3100 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3101 return (-1); 3102 strcpy(base, base_rel); 3103 return (0); 3104 } 3105 3106 static void 3107 linkmap_add(Obj_Entry *obj) 3108 { 3109 struct link_map *l = &obj->linkmap; 3110 struct link_map *prev; 3111 3112 obj->linkmap.l_name = obj->path; 3113 obj->linkmap.l_addr = obj->mapbase; 3114 obj->linkmap.l_ld = obj->dynamic; 3115 #ifdef __mips__ 3116 /* GDB needs load offset on MIPS to use the symbols */ 3117 obj->linkmap.l_offs = obj->relocbase; 3118 #endif 3119 3120 if (r_debug.r_map == NULL) { 3121 r_debug.r_map = l; 3122 return; 3123 } 3124 3125 /* 3126 * Scan to the end of the list, but not past the entry for the 3127 * dynamic linker, which we want to keep at the very end. 3128 */ 3129 for (prev = r_debug.r_map; 3130 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3131 prev = prev->l_next) 3132 ; 3133 3134 /* Link in the new entry. */ 3135 l->l_prev = prev; 3136 l->l_next = prev->l_next; 3137 if (l->l_next != NULL) 3138 l->l_next->l_prev = l; 3139 prev->l_next = l; 3140 } 3141 3142 static void 3143 linkmap_delete(Obj_Entry *obj) 3144 { 3145 struct link_map *l = &obj->linkmap; 3146 3147 if (l->l_prev == NULL) { 3148 if ((r_debug.r_map = l->l_next) != NULL) 3149 l->l_next->l_prev = NULL; 3150 return; 3151 } 3152 3153 if ((l->l_prev->l_next = l->l_next) != NULL) 3154 l->l_next->l_prev = l->l_prev; 3155 } 3156 3157 /* 3158 * Function for the debugger to set a breakpoint on to gain control. 3159 * 3160 * The two parameters allow the debugger to easily find and determine 3161 * what the runtime loader is doing and to whom it is doing it. 3162 * 3163 * When the loadhook trap is hit (r_debug_state, set at program 3164 * initialization), the arguments can be found on the stack: 3165 * 3166 * +8 struct link_map *m 3167 * +4 struct r_debug *rd 3168 * +0 RetAddr 3169 */ 3170 void 3171 r_debug_state(struct r_debug* rd, struct link_map *m) 3172 { 3173 /* 3174 * The following is a hack to force the compiler to emit calls to 3175 * this function, even when optimizing. If the function is empty, 3176 * the compiler is not obliged to emit any code for calls to it, 3177 * even when marked __noinline. However, gdb depends on those 3178 * calls being made. 3179 */ 3180 __asm __volatile("" : : : "memory"); 3181 } 3182 3183 /* 3184 * Get address of the pointer variable in the main program. 3185 * Prefer non-weak symbol over the weak one. 3186 */ 3187 static const void ** 3188 get_program_var_addr(const char *name, RtldLockState *lockstate) 3189 { 3190 SymLook req; 3191 DoneList donelist; 3192 3193 symlook_init(&req, name); 3194 req.lockstate = lockstate; 3195 donelist_init(&donelist); 3196 if (symlook_global(&req, &donelist) != 0) 3197 return (NULL); 3198 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3199 return ((const void **)make_function_pointer(req.sym_out, 3200 req.defobj_out)); 3201 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3202 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3203 else 3204 return ((const void **)(req.defobj_out->relocbase + 3205 req.sym_out->st_value)); 3206 } 3207 3208 /* 3209 * Set a pointer variable in the main program to the given value. This 3210 * is used to set key variables such as "environ" before any of the 3211 * init functions are called. 3212 */ 3213 static void 3214 set_program_var(const char *name, const void *value) 3215 { 3216 const void **addr; 3217 3218 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3219 dbg("\"%s\": *%p <-- %p", name, addr, value); 3220 *addr = value; 3221 } 3222 } 3223 3224 /* 3225 * Search the global objects, including dependencies and main object, 3226 * for the given symbol. 3227 */ 3228 static int 3229 symlook_global(SymLook *req, DoneList *donelist) 3230 { 3231 SymLook req1; 3232 const Objlist_Entry *elm; 3233 int res; 3234 3235 symlook_init_from_req(&req1, req); 3236 3237 /* Search all objects loaded at program start up. */ 3238 if (req->defobj_out == NULL || 3239 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3240 res = symlook_list(&req1, &list_main, donelist); 3241 if (res == 0 && (req->defobj_out == NULL || 3242 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3243 req->sym_out = req1.sym_out; 3244 req->defobj_out = req1.defobj_out; 3245 assert(req->defobj_out != NULL); 3246 } 3247 } 3248 3249 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3250 STAILQ_FOREACH(elm, &list_global, link) { 3251 if (req->defobj_out != NULL && 3252 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3253 break; 3254 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3255 if (res == 0 && (req->defobj_out == NULL || 3256 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3257 req->sym_out = req1.sym_out; 3258 req->defobj_out = req1.defobj_out; 3259 assert(req->defobj_out != NULL); 3260 } 3261 } 3262 3263 return (req->sym_out != NULL ? 0 : ESRCH); 3264 } 3265 3266 /* 3267 * Given a symbol name in a referencing object, find the corresponding 3268 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3269 * no definition was found. Returns a pointer to the Obj_Entry of the 3270 * defining object via the reference parameter DEFOBJ_OUT. 3271 */ 3272 static int 3273 symlook_default(SymLook *req, const Obj_Entry *refobj) 3274 { 3275 DoneList donelist; 3276 const Objlist_Entry *elm; 3277 SymLook req1; 3278 int res; 3279 3280 donelist_init(&donelist); 3281 symlook_init_from_req(&req1, req); 3282 3283 /* Look first in the referencing object if linked symbolically. */ 3284 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3285 res = symlook_obj(&req1, refobj); 3286 if (res == 0) { 3287 req->sym_out = req1.sym_out; 3288 req->defobj_out = req1.defobj_out; 3289 assert(req->defobj_out != NULL); 3290 } 3291 } 3292 3293 symlook_global(req, &donelist); 3294 3295 /* Search all dlopened DAGs containing the referencing object. */ 3296 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3297 if (req->sym_out != NULL && 3298 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3299 break; 3300 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3301 if (res == 0 && (req->sym_out == NULL || 3302 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3303 req->sym_out = req1.sym_out; 3304 req->defobj_out = req1.defobj_out; 3305 assert(req->defobj_out != NULL); 3306 } 3307 } 3308 3309 /* 3310 * Search the dynamic linker itself, and possibly resolve the 3311 * symbol from there. This is how the application links to 3312 * dynamic linker services such as dlopen. 3313 */ 3314 if (req->sym_out == NULL || 3315 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3316 res = symlook_obj(&req1, &obj_rtld); 3317 if (res == 0) { 3318 req->sym_out = req1.sym_out; 3319 req->defobj_out = req1.defobj_out; 3320 assert(req->defobj_out != NULL); 3321 } 3322 } 3323 3324 return (req->sym_out != NULL ? 0 : ESRCH); 3325 } 3326 3327 static int 3328 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3329 { 3330 const Elf_Sym *def; 3331 const Obj_Entry *defobj; 3332 const Objlist_Entry *elm; 3333 SymLook req1; 3334 int res; 3335 3336 def = NULL; 3337 defobj = NULL; 3338 STAILQ_FOREACH(elm, objlist, link) { 3339 if (donelist_check(dlp, elm->obj)) 3340 continue; 3341 symlook_init_from_req(&req1, req); 3342 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3343 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3344 def = req1.sym_out; 3345 defobj = req1.defobj_out; 3346 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3347 break; 3348 } 3349 } 3350 } 3351 if (def != NULL) { 3352 req->sym_out = def; 3353 req->defobj_out = defobj; 3354 return (0); 3355 } 3356 return (ESRCH); 3357 } 3358 3359 /* 3360 * Search the chain of DAGS cointed to by the given Needed_Entry 3361 * for a symbol of the given name. Each DAG is scanned completely 3362 * before advancing to the next one. Returns a pointer to the symbol, 3363 * or NULL if no definition was found. 3364 */ 3365 static int 3366 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3367 { 3368 const Elf_Sym *def; 3369 const Needed_Entry *n; 3370 const Obj_Entry *defobj; 3371 SymLook req1; 3372 int res; 3373 3374 def = NULL; 3375 defobj = NULL; 3376 symlook_init_from_req(&req1, req); 3377 for (n = needed; n != NULL; n = n->next) { 3378 if (n->obj == NULL || 3379 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3380 continue; 3381 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3382 def = req1.sym_out; 3383 defobj = req1.defobj_out; 3384 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3385 break; 3386 } 3387 } 3388 if (def != NULL) { 3389 req->sym_out = def; 3390 req->defobj_out = defobj; 3391 return (0); 3392 } 3393 return (ESRCH); 3394 } 3395 3396 /* 3397 * Search the symbol table of a single shared object for a symbol of 3398 * the given name and version, if requested. Returns a pointer to the 3399 * symbol, or NULL if no definition was found. If the object is 3400 * filter, return filtered symbol from filtee. 3401 * 3402 * The symbol's hash value is passed in for efficiency reasons; that 3403 * eliminates many recomputations of the hash value. 3404 */ 3405 int 3406 symlook_obj(SymLook *req, const Obj_Entry *obj) 3407 { 3408 DoneList donelist; 3409 SymLook req1; 3410 int flags, res, mres; 3411 3412 mres = symlook_obj1(req, obj); 3413 if (mres == 0) { 3414 if (obj->needed_filtees != NULL) { 3415 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3416 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3417 donelist_init(&donelist); 3418 symlook_init_from_req(&req1, req); 3419 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3420 if (res == 0) { 3421 req->sym_out = req1.sym_out; 3422 req->defobj_out = req1.defobj_out; 3423 } 3424 return (res); 3425 } 3426 if (obj->needed_aux_filtees != NULL) { 3427 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3428 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3429 donelist_init(&donelist); 3430 symlook_init_from_req(&req1, req); 3431 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3432 if (res == 0) { 3433 req->sym_out = req1.sym_out; 3434 req->defobj_out = req1.defobj_out; 3435 return (res); 3436 } 3437 } 3438 } 3439 return (mres); 3440 } 3441 3442 static int 3443 symlook_obj1(SymLook *req, const Obj_Entry *obj) 3444 { 3445 unsigned long symnum; 3446 const Elf_Sym *vsymp; 3447 Elf_Versym verndx; 3448 int vcount; 3449 3450 if (obj->buckets == NULL) 3451 return (ESRCH); 3452 3453 vsymp = NULL; 3454 vcount = 0; 3455 symnum = obj->buckets[req->hash % obj->nbuckets]; 3456 3457 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3458 const Elf_Sym *symp; 3459 const char *strp; 3460 3461 if (symnum >= obj->nchains) 3462 return (ESRCH); /* Bad object */ 3463 3464 symp = obj->symtab + symnum; 3465 strp = obj->strtab + symp->st_name; 3466 3467 switch (ELF_ST_TYPE(symp->st_info)) { 3468 case STT_FUNC: 3469 case STT_NOTYPE: 3470 case STT_OBJECT: 3471 case STT_GNU_IFUNC: 3472 if (symp->st_value == 0) 3473 continue; 3474 /* fallthrough */ 3475 case STT_TLS: 3476 if (symp->st_shndx != SHN_UNDEF) 3477 break; 3478 #ifndef __mips__ 3479 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3480 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3481 break; 3482 /* fallthrough */ 3483 #endif 3484 default: 3485 continue; 3486 } 3487 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3488 continue; 3489 3490 if (req->ventry == NULL) { 3491 if (obj->versyms != NULL) { 3492 verndx = VER_NDX(obj->versyms[symnum]); 3493 if (verndx > obj->vernum) { 3494 _rtld_error("%s: symbol %s references wrong version %d", 3495 obj->path, obj->strtab + symnum, verndx); 3496 continue; 3497 } 3498 /* 3499 * If we are not called from dlsym (i.e. this is a normal 3500 * relocation from unversioned binary), accept the symbol 3501 * immediately if it happens to have first version after 3502 * this shared object became versioned. Otherwise, if 3503 * symbol is versioned and not hidden, remember it. If it 3504 * is the only symbol with this name exported by the 3505 * shared object, it will be returned as a match at the 3506 * end of the function. If symbol is global (verndx < 2) 3507 * accept it unconditionally. 3508 */ 3509 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3510 verndx == VER_NDX_GIVEN) { 3511 req->sym_out = symp; 3512 req->defobj_out = obj; 3513 return (0); 3514 } 3515 else if (verndx >= VER_NDX_GIVEN) { 3516 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { 3517 if (vsymp == NULL) 3518 vsymp = symp; 3519 vcount ++; 3520 } 3521 continue; 3522 } 3523 } 3524 req->sym_out = symp; 3525 req->defobj_out = obj; 3526 return (0); 3527 } else { 3528 if (obj->versyms == NULL) { 3529 if (object_match_name(obj, req->ventry->name)) { 3530 _rtld_error("%s: object %s should provide version %s for " 3531 "symbol %s", obj_rtld.path, obj->path, 3532 req->ventry->name, obj->strtab + symnum); 3533 continue; 3534 } 3535 } else { 3536 verndx = VER_NDX(obj->versyms[symnum]); 3537 if (verndx > obj->vernum) { 3538 _rtld_error("%s: symbol %s references wrong version %d", 3539 obj->path, obj->strtab + symnum, verndx); 3540 continue; 3541 } 3542 if (obj->vertab[verndx].hash != req->ventry->hash || 3543 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3544 /* 3545 * Version does not match. Look if this is a global symbol 3546 * and if it is not hidden. If global symbol (verndx < 2) 3547 * is available, use it. Do not return symbol if we are 3548 * called by dlvsym, because dlvsym looks for a specific 3549 * version and default one is not what dlvsym wants. 3550 */ 3551 if ((req->flags & SYMLOOK_DLSYM) || 3552 (obj->versyms[symnum] & VER_NDX_HIDDEN) || 3553 (verndx >= VER_NDX_GIVEN)) 3554 continue; 3555 } 3556 } 3557 req->sym_out = symp; 3558 req->defobj_out = obj; 3559 return (0); 3560 } 3561 } 3562 if (vcount == 1) { 3563 req->sym_out = vsymp; 3564 req->defobj_out = obj; 3565 return (0); 3566 } 3567 return (ESRCH); 3568 } 3569 3570 static void 3571 trace_loaded_objects(Obj_Entry *obj) 3572 { 3573 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 3574 int c; 3575 3576 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 3577 main_local = ""; 3578 3579 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 3580 fmt1 = "\t%o => %p (%x)\n"; 3581 3582 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 3583 fmt2 = "\t%o (%x)\n"; 3584 3585 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 3586 3587 for (; obj; obj = obj->next) { 3588 Needed_Entry *needed; 3589 char *name, *path; 3590 bool is_lib; 3591 3592 if (list_containers && obj->needed != NULL) 3593 rtld_printf("%s:\n", obj->path); 3594 for (needed = obj->needed; needed; needed = needed->next) { 3595 if (needed->obj != NULL) { 3596 if (needed->obj->traced && !list_containers) 3597 continue; 3598 needed->obj->traced = true; 3599 path = needed->obj->path; 3600 } else 3601 path = "not found"; 3602 3603 name = (char *)obj->strtab + needed->name; 3604 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 3605 3606 fmt = is_lib ? fmt1 : fmt2; 3607 while ((c = *fmt++) != '\0') { 3608 switch (c) { 3609 default: 3610 rtld_putchar(c); 3611 continue; 3612 case '\\': 3613 switch (c = *fmt) { 3614 case '\0': 3615 continue; 3616 case 'n': 3617 rtld_putchar('\n'); 3618 break; 3619 case 't': 3620 rtld_putchar('\t'); 3621 break; 3622 } 3623 break; 3624 case '%': 3625 switch (c = *fmt) { 3626 case '\0': 3627 continue; 3628 case '%': 3629 default: 3630 rtld_putchar(c); 3631 break; 3632 case 'A': 3633 rtld_putstr(main_local); 3634 break; 3635 case 'a': 3636 rtld_putstr(obj_main->path); 3637 break; 3638 case 'o': 3639 rtld_putstr(name); 3640 break; 3641 #if 0 3642 case 'm': 3643 rtld_printf("%d", sodp->sod_major); 3644 break; 3645 case 'n': 3646 rtld_printf("%d", sodp->sod_minor); 3647 break; 3648 #endif 3649 case 'p': 3650 rtld_putstr(path); 3651 break; 3652 case 'x': 3653 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 3654 0); 3655 break; 3656 } 3657 break; 3658 } 3659 ++fmt; 3660 } 3661 } 3662 } 3663 } 3664 3665 /* 3666 * Unload a dlopened object and its dependencies from memory and from 3667 * our data structures. It is assumed that the DAG rooted in the 3668 * object has already been unreferenced, and that the object has a 3669 * reference count of 0. 3670 */ 3671 static void 3672 unload_object(Obj_Entry *root) 3673 { 3674 Obj_Entry *obj; 3675 Obj_Entry **linkp; 3676 3677 assert(root->refcount == 0); 3678 3679 /* 3680 * Pass over the DAG removing unreferenced objects from 3681 * appropriate lists. 3682 */ 3683 unlink_object(root); 3684 3685 /* Unmap all objects that are no longer referenced. */ 3686 linkp = &obj_list->next; 3687 while ((obj = *linkp) != NULL) { 3688 if (obj->refcount == 0) { 3689 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 3690 obj->path); 3691 dbg("unloading \"%s\"", obj->path); 3692 unload_filtees(root); 3693 munmap(obj->mapbase, obj->mapsize); 3694 linkmap_delete(obj); 3695 *linkp = obj->next; 3696 obj_count--; 3697 obj_free(obj); 3698 } else 3699 linkp = &obj->next; 3700 } 3701 obj_tail = linkp; 3702 } 3703 3704 static void 3705 unlink_object(Obj_Entry *root) 3706 { 3707 Objlist_Entry *elm; 3708 3709 if (root->refcount == 0) { 3710 /* Remove the object from the RTLD_GLOBAL list. */ 3711 objlist_remove(&list_global, root); 3712 3713 /* Remove the object from all objects' DAG lists. */ 3714 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3715 objlist_remove(&elm->obj->dldags, root); 3716 if (elm->obj != root) 3717 unlink_object(elm->obj); 3718 } 3719 } 3720 } 3721 3722 static void 3723 ref_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 static void 3733 unref_dag(Obj_Entry *root) 3734 { 3735 Objlist_Entry *elm; 3736 3737 assert(root->dag_inited); 3738 STAILQ_FOREACH(elm, &root->dagmembers, link) 3739 elm->obj->refcount--; 3740 } 3741 3742 /* 3743 * Common code for MD __tls_get_addr(). 3744 */ 3745 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 3746 static void * 3747 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 3748 { 3749 Elf_Addr *newdtv, *dtv; 3750 RtldLockState lockstate; 3751 int to_copy; 3752 3753 dtv = *dtvp; 3754 /* Check dtv generation in case new modules have arrived */ 3755 if (dtv[0] != tls_dtv_generation) { 3756 wlock_acquire(rtld_bind_lock, &lockstate); 3757 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3758 to_copy = dtv[1]; 3759 if (to_copy > tls_max_index) 3760 to_copy = tls_max_index; 3761 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 3762 newdtv[0] = tls_dtv_generation; 3763 newdtv[1] = tls_max_index; 3764 free(dtv); 3765 lock_release(rtld_bind_lock, &lockstate); 3766 dtv = *dtvp = newdtv; 3767 } 3768 3769 /* Dynamically allocate module TLS if necessary */ 3770 if (dtv[index + 1] == 0) { 3771 /* Signal safe, wlock will block out signals. */ 3772 wlock_acquire(rtld_bind_lock, &lockstate); 3773 if (!dtv[index + 1]) 3774 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 3775 lock_release(rtld_bind_lock, &lockstate); 3776 } 3777 return ((void *)(dtv[index + 1] + offset)); 3778 } 3779 3780 void * 3781 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 3782 { 3783 Elf_Addr *dtv; 3784 3785 dtv = *dtvp; 3786 /* Check dtv generation in case new modules have arrived */ 3787 if (__predict_true(dtv[0] == tls_dtv_generation && 3788 dtv[index + 1] != 0)) 3789 return ((void *)(dtv[index + 1] + offset)); 3790 return (tls_get_addr_slow(dtvp, index, offset)); 3791 } 3792 3793 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 3794 3795 /* 3796 * Allocate Static TLS using the Variant I method. 3797 */ 3798 void * 3799 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 3800 { 3801 Obj_Entry *obj; 3802 char *tcb; 3803 Elf_Addr **tls; 3804 Elf_Addr *dtv; 3805 Elf_Addr addr; 3806 int i; 3807 3808 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 3809 return (oldtcb); 3810 3811 assert(tcbsize >= TLS_TCB_SIZE); 3812 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 3813 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 3814 3815 if (oldtcb != NULL) { 3816 memcpy(tls, oldtcb, tls_static_space); 3817 free(oldtcb); 3818 3819 /* Adjust the DTV. */ 3820 dtv = tls[0]; 3821 for (i = 0; i < dtv[1]; i++) { 3822 if (dtv[i+2] >= (Elf_Addr)oldtcb && 3823 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 3824 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 3825 } 3826 } 3827 } else { 3828 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3829 tls[0] = dtv; 3830 dtv[0] = tls_dtv_generation; 3831 dtv[1] = tls_max_index; 3832 3833 for (obj = objs; obj; obj = obj->next) { 3834 if (obj->tlsoffset > 0) { 3835 addr = (Elf_Addr)tls + obj->tlsoffset; 3836 if (obj->tlsinitsize > 0) 3837 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3838 if (obj->tlssize > obj->tlsinitsize) 3839 memset((void*) (addr + obj->tlsinitsize), 0, 3840 obj->tlssize - obj->tlsinitsize); 3841 dtv[obj->tlsindex + 1] = addr; 3842 } 3843 } 3844 } 3845 3846 return (tcb); 3847 } 3848 3849 void 3850 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 3851 { 3852 Elf_Addr *dtv; 3853 Elf_Addr tlsstart, tlsend; 3854 int dtvsize, i; 3855 3856 assert(tcbsize >= TLS_TCB_SIZE); 3857 3858 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 3859 tlsend = tlsstart + tls_static_space; 3860 3861 dtv = *(Elf_Addr **)tlsstart; 3862 dtvsize = dtv[1]; 3863 for (i = 0; i < dtvsize; i++) { 3864 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 3865 free((void*)dtv[i+2]); 3866 } 3867 } 3868 free(dtv); 3869 free(tcb); 3870 } 3871 3872 #endif 3873 3874 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 3875 3876 /* 3877 * Allocate Static TLS using the Variant II method. 3878 */ 3879 void * 3880 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 3881 { 3882 Obj_Entry *obj; 3883 size_t size; 3884 char *tls; 3885 Elf_Addr *dtv, *olddtv; 3886 Elf_Addr segbase, oldsegbase, addr; 3887 int i; 3888 3889 size = round(tls_static_space, tcbalign); 3890 3891 assert(tcbsize >= 2*sizeof(Elf_Addr)); 3892 tls = xcalloc(1, size + tcbsize); 3893 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 3894 3895 segbase = (Elf_Addr)(tls + size); 3896 ((Elf_Addr*)segbase)[0] = segbase; 3897 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 3898 3899 dtv[0] = tls_dtv_generation; 3900 dtv[1] = tls_max_index; 3901 3902 if (oldtls) { 3903 /* 3904 * Copy the static TLS block over whole. 3905 */ 3906 oldsegbase = (Elf_Addr) oldtls; 3907 memcpy((void *)(segbase - tls_static_space), 3908 (const void *)(oldsegbase - tls_static_space), 3909 tls_static_space); 3910 3911 /* 3912 * If any dynamic TLS blocks have been created tls_get_addr(), 3913 * move them over. 3914 */ 3915 olddtv = ((Elf_Addr**)oldsegbase)[1]; 3916 for (i = 0; i < olddtv[1]; i++) { 3917 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 3918 dtv[i+2] = olddtv[i+2]; 3919 olddtv[i+2] = 0; 3920 } 3921 } 3922 3923 /* 3924 * We assume that this block was the one we created with 3925 * allocate_initial_tls(). 3926 */ 3927 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 3928 } else { 3929 for (obj = objs; obj; obj = obj->next) { 3930 if (obj->tlsoffset) { 3931 addr = segbase - obj->tlsoffset; 3932 memset((void*) (addr + obj->tlsinitsize), 3933 0, obj->tlssize - obj->tlsinitsize); 3934 if (obj->tlsinit) 3935 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 3936 dtv[obj->tlsindex + 1] = addr; 3937 } 3938 } 3939 } 3940 3941 return (void*) segbase; 3942 } 3943 3944 void 3945 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 3946 { 3947 size_t size; 3948 Elf_Addr* dtv; 3949 int dtvsize, i; 3950 Elf_Addr tlsstart, tlsend; 3951 3952 /* 3953 * Figure out the size of the initial TLS block so that we can 3954 * find stuff which ___tls_get_addr() allocated dynamically. 3955 */ 3956 size = round(tls_static_space, tcbalign); 3957 3958 dtv = ((Elf_Addr**)tls)[1]; 3959 dtvsize = dtv[1]; 3960 tlsend = (Elf_Addr) tls; 3961 tlsstart = tlsend - size; 3962 for (i = 0; i < dtvsize; i++) { 3963 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) { 3964 free((void*) dtv[i+2]); 3965 } 3966 } 3967 3968 free((void*) tlsstart); 3969 free((void*) dtv); 3970 } 3971 3972 #endif 3973 3974 /* 3975 * Allocate TLS block for module with given index. 3976 */ 3977 void * 3978 allocate_module_tls(int index) 3979 { 3980 Obj_Entry* obj; 3981 char* p; 3982 3983 for (obj = obj_list; obj; obj = obj->next) { 3984 if (obj->tlsindex == index) 3985 break; 3986 } 3987 if (!obj) { 3988 _rtld_error("Can't find module with TLS index %d", index); 3989 die(); 3990 } 3991 3992 p = malloc(obj->tlssize); 3993 if (p == NULL) { 3994 _rtld_error("Cannot allocate TLS block for index %d", index); 3995 die(); 3996 } 3997 memcpy(p, obj->tlsinit, obj->tlsinitsize); 3998 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 3999 4000 return p; 4001 } 4002 4003 bool 4004 allocate_tls_offset(Obj_Entry *obj) 4005 { 4006 size_t off; 4007 4008 if (obj->tls_done) 4009 return true; 4010 4011 if (obj->tlssize == 0) { 4012 obj->tls_done = true; 4013 return true; 4014 } 4015 4016 if (obj->tlsindex == 1) 4017 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4018 else 4019 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4020 obj->tlssize, obj->tlsalign); 4021 4022 /* 4023 * If we have already fixed the size of the static TLS block, we 4024 * must stay within that size. When allocating the static TLS, we 4025 * leave a small amount of space spare to be used for dynamically 4026 * loading modules which use static TLS. 4027 */ 4028 if (tls_static_space) { 4029 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4030 return false; 4031 } 4032 4033 tls_last_offset = obj->tlsoffset = off; 4034 tls_last_size = obj->tlssize; 4035 obj->tls_done = true; 4036 4037 return true; 4038 } 4039 4040 void 4041 free_tls_offset(Obj_Entry *obj) 4042 { 4043 4044 /* 4045 * If we were the last thing to allocate out of the static TLS 4046 * block, we give our space back to the 'allocator'. This is a 4047 * simplistic workaround to allow libGL.so.1 to be loaded and 4048 * unloaded multiple times. 4049 */ 4050 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4051 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4052 tls_last_offset -= obj->tlssize; 4053 tls_last_size = 0; 4054 } 4055 } 4056 4057 void * 4058 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4059 { 4060 void *ret; 4061 RtldLockState lockstate; 4062 4063 wlock_acquire(rtld_bind_lock, &lockstate); 4064 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4065 lock_release(rtld_bind_lock, &lockstate); 4066 return (ret); 4067 } 4068 4069 void 4070 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4071 { 4072 RtldLockState lockstate; 4073 4074 wlock_acquire(rtld_bind_lock, &lockstate); 4075 free_tls(tcb, tcbsize, tcbalign); 4076 lock_release(rtld_bind_lock, &lockstate); 4077 } 4078 4079 static void 4080 object_add_name(Obj_Entry *obj, const char *name) 4081 { 4082 Name_Entry *entry; 4083 size_t len; 4084 4085 len = strlen(name); 4086 entry = malloc(sizeof(Name_Entry) + len); 4087 4088 if (entry != NULL) { 4089 strcpy(entry->name, name); 4090 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4091 } 4092 } 4093 4094 static int 4095 object_match_name(const Obj_Entry *obj, const char *name) 4096 { 4097 Name_Entry *entry; 4098 4099 STAILQ_FOREACH(entry, &obj->names, link) { 4100 if (strcmp(name, entry->name) == 0) 4101 return (1); 4102 } 4103 return (0); 4104 } 4105 4106 static Obj_Entry * 4107 locate_dependency(const Obj_Entry *obj, const char *name) 4108 { 4109 const Objlist_Entry *entry; 4110 const Needed_Entry *needed; 4111 4112 STAILQ_FOREACH(entry, &list_main, link) { 4113 if (object_match_name(entry->obj, name)) 4114 return entry->obj; 4115 } 4116 4117 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4118 if (strcmp(obj->strtab + needed->name, name) == 0 || 4119 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4120 /* 4121 * If there is DT_NEEDED for the name we are looking for, 4122 * we are all set. Note that object might not be found if 4123 * dependency was not loaded yet, so the function can 4124 * return NULL here. This is expected and handled 4125 * properly by the caller. 4126 */ 4127 return (needed->obj); 4128 } 4129 } 4130 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4131 obj->path, name); 4132 die(); 4133 } 4134 4135 static int 4136 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4137 const Elf_Vernaux *vna) 4138 { 4139 const Elf_Verdef *vd; 4140 const char *vername; 4141 4142 vername = refobj->strtab + vna->vna_name; 4143 vd = depobj->verdef; 4144 if (vd == NULL) { 4145 _rtld_error("%s: version %s required by %s not defined", 4146 depobj->path, vername, refobj->path); 4147 return (-1); 4148 } 4149 for (;;) { 4150 if (vd->vd_version != VER_DEF_CURRENT) { 4151 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4152 depobj->path, vd->vd_version); 4153 return (-1); 4154 } 4155 if (vna->vna_hash == vd->vd_hash) { 4156 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4157 ((char *)vd + vd->vd_aux); 4158 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4159 return (0); 4160 } 4161 if (vd->vd_next == 0) 4162 break; 4163 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4164 } 4165 if (vna->vna_flags & VER_FLG_WEAK) 4166 return (0); 4167 _rtld_error("%s: version %s required by %s not found", 4168 depobj->path, vername, refobj->path); 4169 return (-1); 4170 } 4171 4172 static int 4173 rtld_verify_object_versions(Obj_Entry *obj) 4174 { 4175 const Elf_Verneed *vn; 4176 const Elf_Verdef *vd; 4177 const Elf_Verdaux *vda; 4178 const Elf_Vernaux *vna; 4179 const Obj_Entry *depobj; 4180 int maxvernum, vernum; 4181 4182 if (obj->ver_checked) 4183 return (0); 4184 obj->ver_checked = true; 4185 4186 maxvernum = 0; 4187 /* 4188 * Walk over defined and required version records and figure out 4189 * max index used by any of them. Do very basic sanity checking 4190 * while there. 4191 */ 4192 vn = obj->verneed; 4193 while (vn != NULL) { 4194 if (vn->vn_version != VER_NEED_CURRENT) { 4195 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4196 obj->path, vn->vn_version); 4197 return (-1); 4198 } 4199 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4200 for (;;) { 4201 vernum = VER_NEED_IDX(vna->vna_other); 4202 if (vernum > maxvernum) 4203 maxvernum = vernum; 4204 if (vna->vna_next == 0) 4205 break; 4206 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4207 } 4208 if (vn->vn_next == 0) 4209 break; 4210 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4211 } 4212 4213 vd = obj->verdef; 4214 while (vd != NULL) { 4215 if (vd->vd_version != VER_DEF_CURRENT) { 4216 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4217 obj->path, vd->vd_version); 4218 return (-1); 4219 } 4220 vernum = VER_DEF_IDX(vd->vd_ndx); 4221 if (vernum > maxvernum) 4222 maxvernum = vernum; 4223 if (vd->vd_next == 0) 4224 break; 4225 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4226 } 4227 4228 if (maxvernum == 0) 4229 return (0); 4230 4231 /* 4232 * Store version information in array indexable by version index. 4233 * Verify that object version requirements are satisfied along the 4234 * way. 4235 */ 4236 obj->vernum = maxvernum + 1; 4237 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4238 4239 vd = obj->verdef; 4240 while (vd != NULL) { 4241 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4242 vernum = VER_DEF_IDX(vd->vd_ndx); 4243 assert(vernum <= maxvernum); 4244 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4245 obj->vertab[vernum].hash = vd->vd_hash; 4246 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4247 obj->vertab[vernum].file = NULL; 4248 obj->vertab[vernum].flags = 0; 4249 } 4250 if (vd->vd_next == 0) 4251 break; 4252 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4253 } 4254 4255 vn = obj->verneed; 4256 while (vn != NULL) { 4257 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4258 if (depobj == NULL) 4259 return (-1); 4260 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4261 for (;;) { 4262 if (check_object_provided_version(obj, depobj, vna)) 4263 return (-1); 4264 vernum = VER_NEED_IDX(vna->vna_other); 4265 assert(vernum <= maxvernum); 4266 obj->vertab[vernum].hash = vna->vna_hash; 4267 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4268 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4269 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4270 VER_INFO_HIDDEN : 0; 4271 if (vna->vna_next == 0) 4272 break; 4273 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4274 } 4275 if (vn->vn_next == 0) 4276 break; 4277 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4278 } 4279 return 0; 4280 } 4281 4282 static int 4283 rtld_verify_versions(const Objlist *objlist) 4284 { 4285 Objlist_Entry *entry; 4286 int rc; 4287 4288 rc = 0; 4289 STAILQ_FOREACH(entry, objlist, link) { 4290 /* 4291 * Skip dummy objects or objects that have their version requirements 4292 * already checked. 4293 */ 4294 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4295 continue; 4296 if (rtld_verify_object_versions(entry->obj) == -1) { 4297 rc = -1; 4298 if (ld_tracing == NULL) 4299 break; 4300 } 4301 } 4302 if (rc == 0 || ld_tracing != NULL) 4303 rc = rtld_verify_object_versions(&obj_rtld); 4304 return rc; 4305 } 4306 4307 const Ver_Entry * 4308 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4309 { 4310 Elf_Versym vernum; 4311 4312 if (obj->vertab) { 4313 vernum = VER_NDX(obj->versyms[symnum]); 4314 if (vernum >= obj->vernum) { 4315 _rtld_error("%s: symbol %s has wrong verneed value %d", 4316 obj->path, obj->strtab + symnum, vernum); 4317 } else if (obj->vertab[vernum].hash != 0) { 4318 return &obj->vertab[vernum]; 4319 } 4320 } 4321 return NULL; 4322 } 4323 4324 int 4325 _rtld_get_stack_prot(void) 4326 { 4327 4328 return (stack_prot); 4329 } 4330 4331 static void 4332 map_stacks_exec(RtldLockState *lockstate) 4333 { 4334 void (*thr_map_stacks_exec)(void); 4335 4336 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4337 return; 4338 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4339 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4340 if (thr_map_stacks_exec != NULL) { 4341 stack_prot |= PROT_EXEC; 4342 thr_map_stacks_exec(); 4343 } 4344 } 4345 4346 void 4347 symlook_init(SymLook *dst, const char *name) 4348 { 4349 4350 bzero(dst, sizeof(*dst)); 4351 dst->name = name; 4352 dst->hash = elf_hash(name); 4353 } 4354 4355 static void 4356 symlook_init_from_req(SymLook *dst, const SymLook *src) 4357 { 4358 4359 dst->name = src->name; 4360 dst->hash = src->hash; 4361 dst->ventry = src->ventry; 4362 dst->flags = src->flags; 4363 dst->defobj_out = NULL; 4364 dst->sym_out = NULL; 4365 dst->lockstate = src->lockstate; 4366 } 4367 4368 /* 4369 * Overrides for libc_pic-provided functions. 4370 */ 4371 4372 int 4373 __getosreldate(void) 4374 { 4375 size_t len; 4376 int oid[2]; 4377 int error, osrel; 4378 4379 if (osreldate != 0) 4380 return (osreldate); 4381 4382 oid[0] = CTL_KERN; 4383 oid[1] = KERN_OSRELDATE; 4384 osrel = 0; 4385 len = sizeof(osrel); 4386 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4387 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4388 osreldate = osrel; 4389 return (osreldate); 4390 } 4391 4392 void 4393 exit(int status) 4394 { 4395 4396 _exit(status); 4397 } 4398 4399 void (*__cleanup)(void); 4400 int __isthreaded = 0; 4401 int _thread_autoinit_dummy_decl = 1; 4402 4403 /* 4404 * No unresolved symbols for rtld. 4405 */ 4406 void 4407 __pthread_cxa_finalize(struct dl_phdr_info *a) 4408 { 4409 } 4410 4411 void 4412 __stack_chk_fail(void) 4413 { 4414 4415 _rtld_error("stack overflow detected; terminated"); 4416 die(); 4417 } 4418 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4419 4420 void 4421 __chk_fail(void) 4422 { 4423 4424 _rtld_error("buffer overflow detected; terminated"); 4425 die(); 4426 } 4427 4428 const char * 4429 rtld_strerror(int errnum) 4430 { 4431 4432 if (errnum < 0 || errnum >= sys_nerr) 4433 return ("Unknown error"); 4434 return (sys_errlist[errnum]); 4435 } 4436