1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37 #include <sys/param.h> 38 #include <sys/mount.h> 39 #include <sys/mman.h> 40 #include <sys/stat.h> 41 #include <sys/sysctl.h> 42 #include <sys/uio.h> 43 #include <sys/utsname.h> 44 #include <sys/ktrace.h> 45 46 #include <dlfcn.h> 47 #include <err.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <stdarg.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 56 #include "debug.h" 57 #include "rtld.h" 58 #include "libmap.h" 59 #include "paths.h" 60 #include "rtld_tls.h" 61 #include "rtld_printf.h" 62 #include "rtld_utrace.h" 63 #include "notes.h" 64 65 /* Types. */ 66 typedef void (*func_ptr_type)(); 67 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 68 69 /* 70 * Function declarations. 71 */ 72 static const char *basename(const char *); 73 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 74 const Elf_Dyn **, const Elf_Dyn **); 75 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 76 const Elf_Dyn *); 77 static void digest_dynamic(Obj_Entry *, int); 78 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 79 static Obj_Entry *dlcheck(void *); 80 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 81 int lo_flags, int mode, RtldLockState *lockstate); 82 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 83 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 84 static bool donelist_check(DoneList *, const Obj_Entry *); 85 static void errmsg_restore(char *); 86 static char *errmsg_save(void); 87 static void *fill_search_info(const char *, size_t, void *); 88 static char *find_library(const char *, const Obj_Entry *, int *); 89 static const char *gethints(bool); 90 static void init_dag(Obj_Entry *); 91 static void init_pagesizes(Elf_Auxinfo **aux_info); 92 static void init_rtld(caddr_t, Elf_Auxinfo **); 93 static void initlist_add_neededs(Needed_Entry *, Objlist *); 94 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 95 static void linkmap_add(Obj_Entry *); 96 static void linkmap_delete(Obj_Entry *); 97 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 98 static void unload_filtees(Obj_Entry *); 99 static int load_needed_objects(Obj_Entry *, int); 100 static int load_preload_objects(void); 101 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 102 static void map_stacks_exec(RtldLockState *); 103 static Obj_Entry *obj_from_addr(const void *); 104 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 105 static void objlist_call_init(Objlist *, RtldLockState *); 106 static void objlist_clear(Objlist *); 107 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 108 static void objlist_init(Objlist *); 109 static void objlist_push_head(Objlist *, Obj_Entry *); 110 static void objlist_push_tail(Objlist *, Obj_Entry *); 111 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 112 static void objlist_remove(Objlist *, Obj_Entry *); 113 static int parse_libdir(const char *); 114 static void *path_enumerate(const char *, path_enum_proc, void *); 115 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 116 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 117 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 118 int flags, RtldLockState *lockstate); 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 char *search_library_pathfds(const char *, const char *, int *); 129 static const void **get_program_var_addr(const char *, RtldLockState *); 130 static void set_program_var(const char *, const void *); 131 static int symlook_default(SymLook *, const Obj_Entry *refobj); 132 static int symlook_global(SymLook *, DoneList *); 133 static void symlook_init_from_req(SymLook *, const SymLook *); 134 static int symlook_list(SymLook *, const Objlist *, DoneList *); 135 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 136 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 137 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 138 static void trace_loaded_objects(Obj_Entry *); 139 static void unlink_object(Obj_Entry *); 140 static void unload_object(Obj_Entry *); 141 static void unref_dag(Obj_Entry *); 142 static void ref_dag(Obj_Entry *); 143 static char *origin_subst_one(Obj_Entry *, char *, const char *, 144 const char *, bool); 145 static char *origin_subst(Obj_Entry *, char *); 146 static bool obj_resolve_origin(Obj_Entry *obj); 147 static void preinit_main(void); 148 static int rtld_verify_versions(const Objlist *); 149 static int rtld_verify_object_versions(Obj_Entry *); 150 static void object_add_name(Obj_Entry *, const char *); 151 static int object_match_name(const Obj_Entry *, const char *); 152 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 153 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 154 struct dl_phdr_info *phdr_info); 155 static uint32_t gnu_hash(const char *); 156 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 157 const unsigned long); 158 159 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 160 void _r_debug_postinit(struct link_map *) __noinline __exported; 161 162 int __sys_openat(int, const char *, int, ...); 163 164 /* 165 * Data declarations. 166 */ 167 static char *error_message; /* Message for dlerror(), or NULL */ 168 struct r_debug r_debug __exported; /* for GDB; */ 169 static bool libmap_disable; /* Disable libmap */ 170 static bool ld_loadfltr; /* Immediate filters processing */ 171 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 172 static bool trust; /* False for setuid and setgid programs */ 173 static bool dangerous_ld_env; /* True if environment variables have been 174 used to affect the libraries loaded */ 175 static char *ld_bind_now; /* Environment variable for immediate binding */ 176 static char *ld_debug; /* Environment variable for debugging */ 177 static char *ld_library_path; /* Environment variable for search path */ 178 static char *ld_library_dirs; /* Environment variable for library descriptors */ 179 static char *ld_preload; /* Environment variable for libraries to 180 load first */ 181 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 182 static char *ld_tracing; /* Called from ldd to print libs */ 183 static char *ld_utrace; /* Use utrace() to log events. */ 184 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 185 static Obj_Entry *obj_main; /* The main program shared object */ 186 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 187 static unsigned int obj_count; /* Number of objects in obj_list */ 188 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 189 190 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 191 STAILQ_HEAD_INITIALIZER(list_global); 192 static Objlist list_main = /* Objects loaded at program startup */ 193 STAILQ_HEAD_INITIALIZER(list_main); 194 static Objlist list_fini = /* Objects needing fini() calls */ 195 STAILQ_HEAD_INITIALIZER(list_fini); 196 197 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 198 199 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 200 201 extern Elf_Dyn _DYNAMIC; 202 #pragma weak _DYNAMIC 203 204 int dlclose(void *) __exported; 205 char *dlerror(void) __exported; 206 void *dlopen(const char *, int) __exported; 207 void *fdlopen(int, int) __exported; 208 void *dlsym(void *, const char *) __exported; 209 dlfunc_t dlfunc(void *, const char *) __exported; 210 void *dlvsym(void *, const char *, const char *) __exported; 211 int dladdr(const void *, Dl_info *) __exported; 212 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 213 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 214 int dlinfo(void *, int , void *) __exported; 215 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 216 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 217 int _rtld_get_stack_prot(void) __exported; 218 int _rtld_is_dlopened(void *) __exported; 219 void _rtld_error(const char *, ...) __exported; 220 221 int npagesizes, osreldate; 222 size_t *pagesizes; 223 224 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 225 226 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 227 static int max_stack_flags; 228 229 /* 230 * Global declarations normally provided by crt1. The dynamic linker is 231 * not built with crt1, so we have to provide them ourselves. 232 */ 233 char *__progname; 234 char **environ; 235 236 /* 237 * Used to pass argc, argv to init functions. 238 */ 239 int main_argc; 240 char **main_argv; 241 242 /* 243 * Globals to control TLS allocation. 244 */ 245 size_t tls_last_offset; /* Static TLS offset of last module */ 246 size_t tls_last_size; /* Static TLS size of last module */ 247 size_t tls_static_space; /* Static TLS space allocated */ 248 size_t tls_static_max_align; 249 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 250 int tls_max_index = 1; /* Largest module index allocated */ 251 252 bool ld_library_path_rpath = false; 253 254 /* 255 * Globals for path names, and such 256 */ 257 char *ld_elf_hints_default = _PATH_ELF_HINTS; 258 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 259 char *ld_path_rtld = _PATH_RTLD; 260 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 261 char *ld_env_prefix = LD_; 262 263 /* 264 * Fill in a DoneList with an allocation large enough to hold all of 265 * the currently-loaded objects. Keep this as a macro since it calls 266 * alloca and we want that to occur within the scope of the caller. 267 */ 268 #define donelist_init(dlp) \ 269 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 270 assert((dlp)->objs != NULL), \ 271 (dlp)->num_alloc = obj_count, \ 272 (dlp)->num_used = 0) 273 274 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 275 if (ld_utrace != NULL) \ 276 ld_utrace_log(e, h, mb, ms, r, n); \ 277 } while (0) 278 279 static void 280 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 281 int refcnt, const char *name) 282 { 283 struct utrace_rtld ut; 284 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 285 286 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 287 ut.event = event; 288 ut.handle = handle; 289 ut.mapbase = mapbase; 290 ut.mapsize = mapsize; 291 ut.refcnt = refcnt; 292 bzero(ut.name, sizeof(ut.name)); 293 if (name) 294 strlcpy(ut.name, name, sizeof(ut.name)); 295 utrace(&ut, sizeof(ut)); 296 } 297 298 #ifdef RTLD_VARIANT_ENV_NAMES 299 /* 300 * construct the env variable based on the type of binary that's 301 * running. 302 */ 303 static inline const char * 304 _LD(const char *var) 305 { 306 static char buffer[128]; 307 308 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 309 strlcat(buffer, var, sizeof(buffer)); 310 return (buffer); 311 } 312 #else 313 #define _LD(x) LD_ x 314 #endif 315 316 /* 317 * Main entry point for dynamic linking. The first argument is the 318 * stack pointer. The stack is expected to be laid out as described 319 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 320 * Specifically, the stack pointer points to a word containing 321 * ARGC. Following that in the stack is a null-terminated sequence 322 * of pointers to argument strings. Then comes a null-terminated 323 * sequence of pointers to environment strings. Finally, there is a 324 * sequence of "auxiliary vector" entries. 325 * 326 * The second argument points to a place to store the dynamic linker's 327 * exit procedure pointer and the third to a place to store the main 328 * program's object. 329 * 330 * The return value is the main program's entry point. 331 */ 332 func_ptr_type 333 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 334 { 335 Elf_Auxinfo *aux_info[AT_COUNT]; 336 int i; 337 int argc; 338 char **argv; 339 char **env; 340 Elf_Auxinfo *aux; 341 Elf_Auxinfo *auxp; 342 const char *argv0; 343 Objlist_Entry *entry; 344 Obj_Entry *obj; 345 Obj_Entry *preload_tail; 346 Obj_Entry *last_interposer; 347 Objlist initlist; 348 RtldLockState lockstate; 349 char *library_path_rpath; 350 int mib[2]; 351 size_t len; 352 353 /* 354 * On entry, the dynamic linker itself has not been relocated yet. 355 * Be very careful not to reference any global data until after 356 * init_rtld has returned. It is OK to reference file-scope statics 357 * and string constants, and to call static and global functions. 358 */ 359 360 /* Find the auxiliary vector on the stack. */ 361 argc = *sp++; 362 argv = (char **) sp; 363 sp += argc + 1; /* Skip over arguments and NULL terminator */ 364 env = (char **) sp; 365 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 366 ; 367 aux = (Elf_Auxinfo *) sp; 368 369 /* Digest the auxiliary vector. */ 370 for (i = 0; i < AT_COUNT; i++) 371 aux_info[i] = NULL; 372 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 373 if (auxp->a_type < AT_COUNT) 374 aux_info[auxp->a_type] = auxp; 375 } 376 377 /* Initialize and relocate ourselves. */ 378 assert(aux_info[AT_BASE] != NULL); 379 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 380 381 __progname = obj_rtld.path; 382 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 383 environ = env; 384 main_argc = argc; 385 main_argv = argv; 386 387 if (aux_info[AT_CANARY] != NULL && 388 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 389 i = aux_info[AT_CANARYLEN]->a_un.a_val; 390 if (i > sizeof(__stack_chk_guard)) 391 i = sizeof(__stack_chk_guard); 392 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 393 } else { 394 mib[0] = CTL_KERN; 395 mib[1] = KERN_ARND; 396 397 len = sizeof(__stack_chk_guard); 398 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 399 len != sizeof(__stack_chk_guard)) { 400 /* If sysctl was unsuccessful, use the "terminator canary". */ 401 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 402 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 403 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 404 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 405 } 406 } 407 408 trust = !issetugid(); 409 410 md_abi_variant_hook(aux_info); 411 412 ld_bind_now = getenv(_LD("BIND_NOW")); 413 /* 414 * If the process is tainted, then we un-set the dangerous environment 415 * variables. The process will be marked as tainted until setuid(2) 416 * is called. If any child process calls setuid(2) we do not want any 417 * future processes to honor the potentially un-safe variables. 418 */ 419 if (!trust) { 420 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 421 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 422 unsetenv(_LD("LIBMAP_DISABLE")) || 423 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 424 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 425 _rtld_error("environment corrupt; aborting"); 426 rtld_die(); 427 } 428 } 429 ld_debug = getenv(_LD("DEBUG")); 430 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 431 libmap_override = getenv(_LD("LIBMAP")); 432 ld_library_path = getenv(_LD("LIBRARY_PATH")); 433 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 434 ld_preload = getenv(_LD("PRELOAD")); 435 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 436 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 437 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 438 if (library_path_rpath != NULL) { 439 if (library_path_rpath[0] == 'y' || 440 library_path_rpath[0] == 'Y' || 441 library_path_rpath[0] == '1') 442 ld_library_path_rpath = true; 443 else 444 ld_library_path_rpath = false; 445 } 446 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 447 (ld_library_path != NULL) || (ld_preload != NULL) || 448 (ld_elf_hints_path != NULL) || ld_loadfltr; 449 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 450 ld_utrace = getenv(_LD("UTRACE")); 451 452 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 453 ld_elf_hints_path = ld_elf_hints_default; 454 455 if (ld_debug != NULL && *ld_debug != '\0') 456 debug = 1; 457 dbg("%s is initialized, base address = %p", __progname, 458 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 459 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 460 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 461 462 dbg("initializing thread locks"); 463 lockdflt_init(); 464 465 /* 466 * Load the main program, or process its program header if it is 467 * already loaded. 468 */ 469 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 470 int fd = aux_info[AT_EXECFD]->a_un.a_val; 471 dbg("loading main program"); 472 obj_main = map_object(fd, argv0, NULL); 473 close(fd); 474 if (obj_main == NULL) 475 rtld_die(); 476 max_stack_flags = obj->stack_flags; 477 } else { /* Main program already loaded. */ 478 const Elf_Phdr *phdr; 479 int phnum; 480 caddr_t entry; 481 482 dbg("processing main program's program header"); 483 assert(aux_info[AT_PHDR] != NULL); 484 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 485 assert(aux_info[AT_PHNUM] != NULL); 486 phnum = aux_info[AT_PHNUM]->a_un.a_val; 487 assert(aux_info[AT_PHENT] != NULL); 488 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 489 assert(aux_info[AT_ENTRY] != NULL); 490 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 491 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 492 rtld_die(); 493 } 494 495 if (aux_info[AT_EXECPATH] != NULL) { 496 char *kexecpath; 497 char buf[MAXPATHLEN]; 498 499 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 500 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 501 if (kexecpath[0] == '/') 502 obj_main->path = kexecpath; 503 else if (getcwd(buf, sizeof(buf)) == NULL || 504 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 505 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 506 obj_main->path = xstrdup(argv0); 507 else 508 obj_main->path = xstrdup(buf); 509 } else { 510 dbg("No AT_EXECPATH"); 511 obj_main->path = xstrdup(argv0); 512 } 513 dbg("obj_main path %s", obj_main->path); 514 obj_main->mainprog = true; 515 516 if (aux_info[AT_STACKPROT] != NULL && 517 aux_info[AT_STACKPROT]->a_un.a_val != 0) 518 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 519 520 #ifndef COMPAT_32BIT 521 /* 522 * Get the actual dynamic linker pathname from the executable if 523 * possible. (It should always be possible.) That ensures that 524 * gdb will find the right dynamic linker even if a non-standard 525 * one is being used. 526 */ 527 if (obj_main->interp != NULL && 528 strcmp(obj_main->interp, obj_rtld.path) != 0) { 529 free(obj_rtld.path); 530 obj_rtld.path = xstrdup(obj_main->interp); 531 __progname = obj_rtld.path; 532 } 533 #endif 534 535 digest_dynamic(obj_main, 0); 536 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 537 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 538 obj_main->dynsymcount); 539 540 linkmap_add(obj_main); 541 linkmap_add(&obj_rtld); 542 543 /* Link the main program into the list of objects. */ 544 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 545 obj_count++; 546 obj_loads++; 547 548 /* Initialize a fake symbol for resolving undefined weak references. */ 549 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 550 sym_zero.st_shndx = SHN_UNDEF; 551 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 552 553 if (!libmap_disable) 554 libmap_disable = (bool)lm_init(libmap_override); 555 556 dbg("loading LD_PRELOAD libraries"); 557 if (load_preload_objects() == -1) 558 rtld_die(); 559 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 560 561 dbg("loading needed objects"); 562 if (load_needed_objects(obj_main, 0) == -1) 563 rtld_die(); 564 565 /* Make a list of all objects loaded at startup. */ 566 last_interposer = obj_main; 567 TAILQ_FOREACH(obj, &obj_list, next) { 568 if (obj->marker) 569 continue; 570 if (obj->z_interpose && obj != obj_main) { 571 objlist_put_after(&list_main, last_interposer, obj); 572 last_interposer = obj; 573 } else { 574 objlist_push_tail(&list_main, obj); 575 } 576 obj->refcount++; 577 } 578 579 dbg("checking for required versions"); 580 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 581 rtld_die(); 582 583 if (ld_tracing) { /* We're done */ 584 trace_loaded_objects(obj_main); 585 exit(0); 586 } 587 588 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 589 dump_relocations(obj_main); 590 exit (0); 591 } 592 593 /* 594 * Processing tls relocations requires having the tls offsets 595 * initialized. Prepare offsets before starting initial 596 * relocation processing. 597 */ 598 dbg("initializing initial thread local storage offsets"); 599 STAILQ_FOREACH(entry, &list_main, link) { 600 /* 601 * Allocate all the initial objects out of the static TLS 602 * block even if they didn't ask for it. 603 */ 604 allocate_tls_offset(entry->obj); 605 } 606 607 if (relocate_objects(obj_main, 608 ld_bind_now != NULL && *ld_bind_now != '\0', 609 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 610 rtld_die(); 611 612 dbg("doing copy relocations"); 613 if (do_copy_relocations(obj_main) == -1) 614 rtld_die(); 615 616 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 617 dump_relocations(obj_main); 618 exit (0); 619 } 620 621 /* 622 * Setup TLS for main thread. This must be done after the 623 * relocations are processed, since tls initialization section 624 * might be the subject for relocations. 625 */ 626 dbg("initializing initial thread local storage"); 627 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 628 629 dbg("initializing key program variables"); 630 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 631 set_program_var("environ", env); 632 set_program_var("__elf_aux_vector", aux); 633 634 /* Make a list of init functions to call. */ 635 objlist_init(&initlist); 636 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 637 preload_tail, &initlist); 638 639 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 640 641 map_stacks_exec(NULL); 642 ifunc_init(aux); 643 644 dbg("resolving ifuncs"); 645 if (resolve_objects_ifunc(obj_main, 646 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 647 NULL) == -1) 648 rtld_die(); 649 650 if (!obj_main->crt_no_init) { 651 /* 652 * Make sure we don't call the main program's init and fini 653 * functions for binaries linked with old crt1 which calls 654 * _init itself. 655 */ 656 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 657 obj_main->preinit_array = obj_main->init_array = 658 obj_main->fini_array = (Elf_Addr)NULL; 659 } 660 661 wlock_acquire(rtld_bind_lock, &lockstate); 662 if (obj_main->crt_no_init) 663 preinit_main(); 664 objlist_call_init(&initlist, &lockstate); 665 _r_debug_postinit(&obj_main->linkmap); 666 objlist_clear(&initlist); 667 dbg("loading filtees"); 668 TAILQ_FOREACH(obj, &obj_list, next) { 669 if (obj->marker) 670 continue; 671 if (ld_loadfltr || obj->z_loadfltr) 672 load_filtees(obj, 0, &lockstate); 673 } 674 lock_release(rtld_bind_lock, &lockstate); 675 676 dbg("transferring control to program entry point = %p", obj_main->entry); 677 678 /* Return the exit procedure and the program entry point. */ 679 *exit_proc = rtld_exit; 680 *objp = obj_main; 681 return (func_ptr_type) obj_main->entry; 682 } 683 684 void * 685 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 686 { 687 void *ptr; 688 Elf_Addr target; 689 690 ptr = (void *)make_function_pointer(def, obj); 691 target = call_ifunc_resolver(ptr); 692 return ((void *)target); 693 } 694 695 /* 696 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 697 * Changes to this function should be applied there as well. 698 */ 699 Elf_Addr 700 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 701 { 702 const Elf_Rel *rel; 703 const Elf_Sym *def; 704 const Obj_Entry *defobj; 705 Elf_Addr *where; 706 Elf_Addr target; 707 RtldLockState lockstate; 708 709 rlock_acquire(rtld_bind_lock, &lockstate); 710 if (sigsetjmp(lockstate.env, 0) != 0) 711 lock_upgrade(rtld_bind_lock, &lockstate); 712 if (obj->pltrel) 713 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 714 else 715 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 716 717 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 718 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 719 NULL, &lockstate); 720 if (def == NULL) 721 rtld_die(); 722 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 723 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 724 else 725 target = (Elf_Addr)(defobj->relocbase + def->st_value); 726 727 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 728 defobj->strtab + def->st_name, basename(obj->path), 729 (void *)target, basename(defobj->path)); 730 731 /* 732 * Write the new contents for the jmpslot. Note that depending on 733 * architecture, the value which we need to return back to the 734 * lazy binding trampoline may or may not be the target 735 * address. The value returned from reloc_jmpslot() is the value 736 * that the trampoline needs. 737 */ 738 target = reloc_jmpslot(where, target, defobj, obj, rel); 739 lock_release(rtld_bind_lock, &lockstate); 740 return target; 741 } 742 743 /* 744 * Error reporting function. Use it like printf. If formats the message 745 * into a buffer, and sets things up so that the next call to dlerror() 746 * will return the message. 747 */ 748 void 749 _rtld_error(const char *fmt, ...) 750 { 751 static char buf[512]; 752 va_list ap; 753 754 va_start(ap, fmt); 755 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 756 error_message = buf; 757 va_end(ap); 758 } 759 760 /* 761 * Return a dynamically-allocated copy of the current error message, if any. 762 */ 763 static char * 764 errmsg_save(void) 765 { 766 return error_message == NULL ? NULL : xstrdup(error_message); 767 } 768 769 /* 770 * Restore the current error message from a copy which was previously saved 771 * by errmsg_save(). The copy is freed. 772 */ 773 static void 774 errmsg_restore(char *saved_msg) 775 { 776 if (saved_msg == NULL) 777 error_message = NULL; 778 else { 779 _rtld_error("%s", saved_msg); 780 free(saved_msg); 781 } 782 } 783 784 static const char * 785 basename(const char *name) 786 { 787 const char *p = strrchr(name, '/'); 788 return p != NULL ? p + 1 : name; 789 } 790 791 static struct utsname uts; 792 793 static char * 794 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 795 const char *subst, bool may_free) 796 { 797 char *p, *p1, *res, *resp; 798 int subst_len, kw_len, subst_count, old_len, new_len; 799 800 kw_len = strlen(kw); 801 802 /* 803 * First, count the number of the keyword occurrences, to 804 * preallocate the final string. 805 */ 806 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 807 p1 = strstr(p, kw); 808 if (p1 == NULL) 809 break; 810 } 811 812 /* 813 * If the keyword is not found, just return. 814 * 815 * Return non-substituted string if resolution failed. We 816 * cannot do anything more reasonable, the failure mode of the 817 * caller is unresolved library anyway. 818 */ 819 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 820 return (may_free ? real : xstrdup(real)); 821 if (obj != NULL) 822 subst = obj->origin_path; 823 824 /* 825 * There is indeed something to substitute. Calculate the 826 * length of the resulting string, and allocate it. 827 */ 828 subst_len = strlen(subst); 829 old_len = strlen(real); 830 new_len = old_len + (subst_len - kw_len) * subst_count; 831 res = xmalloc(new_len + 1); 832 833 /* 834 * Now, execute the substitution loop. 835 */ 836 for (p = real, resp = res, *resp = '\0';;) { 837 p1 = strstr(p, kw); 838 if (p1 != NULL) { 839 /* Copy the prefix before keyword. */ 840 memcpy(resp, p, p1 - p); 841 resp += p1 - p; 842 /* Keyword replacement. */ 843 memcpy(resp, subst, subst_len); 844 resp += subst_len; 845 *resp = '\0'; 846 p = p1 + kw_len; 847 } else 848 break; 849 } 850 851 /* Copy to the end of string and finish. */ 852 strcat(resp, p); 853 if (may_free) 854 free(real); 855 return (res); 856 } 857 858 static char * 859 origin_subst(Obj_Entry *obj, char *real) 860 { 861 char *res1, *res2, *res3, *res4; 862 863 if (obj == NULL || !trust) 864 return (xstrdup(real)); 865 if (uts.sysname[0] == '\0') { 866 if (uname(&uts) != 0) { 867 _rtld_error("utsname failed: %d", errno); 868 return (NULL); 869 } 870 } 871 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 872 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 873 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 874 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 875 return (res4); 876 } 877 878 void 879 rtld_die(void) 880 { 881 const char *msg = dlerror(); 882 883 if (msg == NULL) 884 msg = "Fatal error"; 885 rtld_fdputstr(STDERR_FILENO, msg); 886 rtld_fdputchar(STDERR_FILENO, '\n'); 887 _exit(1); 888 } 889 890 /* 891 * Process a shared object's DYNAMIC section, and save the important 892 * information in its Obj_Entry structure. 893 */ 894 static void 895 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 896 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 897 { 898 const Elf_Dyn *dynp; 899 Needed_Entry **needed_tail = &obj->needed; 900 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 901 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 902 const Elf_Hashelt *hashtab; 903 const Elf32_Word *hashval; 904 Elf32_Word bkt, nmaskwords; 905 int bloom_size32; 906 int plttype = DT_REL; 907 908 *dyn_rpath = NULL; 909 *dyn_soname = NULL; 910 *dyn_runpath = NULL; 911 912 obj->bind_now = false; 913 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 914 switch (dynp->d_tag) { 915 916 case DT_REL: 917 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 918 break; 919 920 case DT_RELSZ: 921 obj->relsize = dynp->d_un.d_val; 922 break; 923 924 case DT_RELENT: 925 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 926 break; 927 928 case DT_JMPREL: 929 obj->pltrel = (const Elf_Rel *) 930 (obj->relocbase + dynp->d_un.d_ptr); 931 break; 932 933 case DT_PLTRELSZ: 934 obj->pltrelsize = dynp->d_un.d_val; 935 break; 936 937 case DT_RELA: 938 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 939 break; 940 941 case DT_RELASZ: 942 obj->relasize = dynp->d_un.d_val; 943 break; 944 945 case DT_RELAENT: 946 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 947 break; 948 949 case DT_PLTREL: 950 plttype = dynp->d_un.d_val; 951 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 952 break; 953 954 case DT_SYMTAB: 955 obj->symtab = (const Elf_Sym *) 956 (obj->relocbase + dynp->d_un.d_ptr); 957 break; 958 959 case DT_SYMENT: 960 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 961 break; 962 963 case DT_STRTAB: 964 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 965 break; 966 967 case DT_STRSZ: 968 obj->strsize = dynp->d_un.d_val; 969 break; 970 971 case DT_VERNEED: 972 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 973 dynp->d_un.d_val); 974 break; 975 976 case DT_VERNEEDNUM: 977 obj->verneednum = dynp->d_un.d_val; 978 break; 979 980 case DT_VERDEF: 981 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 982 dynp->d_un.d_val); 983 break; 984 985 case DT_VERDEFNUM: 986 obj->verdefnum = dynp->d_un.d_val; 987 break; 988 989 case DT_VERSYM: 990 obj->versyms = (const Elf_Versym *)(obj->relocbase + 991 dynp->d_un.d_val); 992 break; 993 994 case DT_HASH: 995 { 996 hashtab = (const Elf_Hashelt *)(obj->relocbase + 997 dynp->d_un.d_ptr); 998 obj->nbuckets = hashtab[0]; 999 obj->nchains = hashtab[1]; 1000 obj->buckets = hashtab + 2; 1001 obj->chains = obj->buckets + obj->nbuckets; 1002 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1003 obj->buckets != NULL; 1004 } 1005 break; 1006 1007 case DT_GNU_HASH: 1008 { 1009 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1010 dynp->d_un.d_ptr); 1011 obj->nbuckets_gnu = hashtab[0]; 1012 obj->symndx_gnu = hashtab[1]; 1013 nmaskwords = hashtab[2]; 1014 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1015 obj->maskwords_bm_gnu = nmaskwords - 1; 1016 obj->shift2_gnu = hashtab[3]; 1017 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1018 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1019 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1020 obj->symndx_gnu; 1021 /* Number of bitmask words is required to be power of 2 */ 1022 obj->valid_hash_gnu = powerof2(nmaskwords) && 1023 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1024 } 1025 break; 1026 1027 case DT_NEEDED: 1028 if (!obj->rtld) { 1029 Needed_Entry *nep = NEW(Needed_Entry); 1030 nep->name = dynp->d_un.d_val; 1031 nep->obj = NULL; 1032 nep->next = NULL; 1033 1034 *needed_tail = nep; 1035 needed_tail = &nep->next; 1036 } 1037 break; 1038 1039 case DT_FILTER: 1040 if (!obj->rtld) { 1041 Needed_Entry *nep = NEW(Needed_Entry); 1042 nep->name = dynp->d_un.d_val; 1043 nep->obj = NULL; 1044 nep->next = NULL; 1045 1046 *needed_filtees_tail = nep; 1047 needed_filtees_tail = &nep->next; 1048 } 1049 break; 1050 1051 case DT_AUXILIARY: 1052 if (!obj->rtld) { 1053 Needed_Entry *nep = NEW(Needed_Entry); 1054 nep->name = dynp->d_un.d_val; 1055 nep->obj = NULL; 1056 nep->next = NULL; 1057 1058 *needed_aux_filtees_tail = nep; 1059 needed_aux_filtees_tail = &nep->next; 1060 } 1061 break; 1062 1063 case DT_PLTGOT: 1064 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1065 break; 1066 1067 case DT_TEXTREL: 1068 obj->textrel = true; 1069 break; 1070 1071 case DT_SYMBOLIC: 1072 obj->symbolic = true; 1073 break; 1074 1075 case DT_RPATH: 1076 /* 1077 * We have to wait until later to process this, because we 1078 * might not have gotten the address of the string table yet. 1079 */ 1080 *dyn_rpath = dynp; 1081 break; 1082 1083 case DT_SONAME: 1084 *dyn_soname = dynp; 1085 break; 1086 1087 case DT_RUNPATH: 1088 *dyn_runpath = dynp; 1089 break; 1090 1091 case DT_INIT: 1092 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1093 break; 1094 1095 case DT_PREINIT_ARRAY: 1096 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1097 break; 1098 1099 case DT_PREINIT_ARRAYSZ: 1100 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1101 break; 1102 1103 case DT_INIT_ARRAY: 1104 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1105 break; 1106 1107 case DT_INIT_ARRAYSZ: 1108 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1109 break; 1110 1111 case DT_FINI: 1112 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1113 break; 1114 1115 case DT_FINI_ARRAY: 1116 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1117 break; 1118 1119 case DT_FINI_ARRAYSZ: 1120 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1121 break; 1122 1123 /* 1124 * Don't process DT_DEBUG on MIPS as the dynamic section 1125 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1126 */ 1127 1128 #ifndef __mips__ 1129 case DT_DEBUG: 1130 if (!early) 1131 dbg("Filling in DT_DEBUG entry"); 1132 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1133 break; 1134 #endif 1135 1136 case DT_FLAGS: 1137 if (dynp->d_un.d_val & DF_ORIGIN) 1138 obj->z_origin = true; 1139 if (dynp->d_un.d_val & DF_SYMBOLIC) 1140 obj->symbolic = true; 1141 if (dynp->d_un.d_val & DF_TEXTREL) 1142 obj->textrel = true; 1143 if (dynp->d_un.d_val & DF_BIND_NOW) 1144 obj->bind_now = true; 1145 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1146 ;*/ 1147 break; 1148 #ifdef __mips__ 1149 case DT_MIPS_LOCAL_GOTNO: 1150 obj->local_gotno = dynp->d_un.d_val; 1151 break; 1152 1153 case DT_MIPS_SYMTABNO: 1154 obj->symtabno = dynp->d_un.d_val; 1155 break; 1156 1157 case DT_MIPS_GOTSYM: 1158 obj->gotsym = dynp->d_un.d_val; 1159 break; 1160 1161 case DT_MIPS_RLD_MAP: 1162 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1163 break; 1164 #endif 1165 1166 #ifdef __powerpc64__ 1167 case DT_PPC64_GLINK: 1168 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1169 break; 1170 #endif 1171 1172 case DT_FLAGS_1: 1173 if (dynp->d_un.d_val & DF_1_NOOPEN) 1174 obj->z_noopen = true; 1175 if (dynp->d_un.d_val & DF_1_ORIGIN) 1176 obj->z_origin = true; 1177 if (dynp->d_un.d_val & DF_1_GLOBAL) 1178 obj->z_global = true; 1179 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1180 obj->bind_now = true; 1181 if (dynp->d_un.d_val & DF_1_NODELETE) 1182 obj->z_nodelete = true; 1183 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1184 obj->z_loadfltr = true; 1185 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1186 obj->z_interpose = true; 1187 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1188 obj->z_nodeflib = true; 1189 break; 1190 1191 default: 1192 if (!early) { 1193 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1194 (long)dynp->d_tag); 1195 } 1196 break; 1197 } 1198 } 1199 1200 obj->traced = false; 1201 1202 if (plttype == DT_RELA) { 1203 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1204 obj->pltrel = NULL; 1205 obj->pltrelasize = obj->pltrelsize; 1206 obj->pltrelsize = 0; 1207 } 1208 1209 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1210 if (obj->valid_hash_sysv) 1211 obj->dynsymcount = obj->nchains; 1212 else if (obj->valid_hash_gnu) { 1213 obj->dynsymcount = 0; 1214 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1215 if (obj->buckets_gnu[bkt] == 0) 1216 continue; 1217 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1218 do 1219 obj->dynsymcount++; 1220 while ((*hashval++ & 1u) == 0); 1221 } 1222 obj->dynsymcount += obj->symndx_gnu; 1223 } 1224 } 1225 1226 static bool 1227 obj_resolve_origin(Obj_Entry *obj) 1228 { 1229 1230 if (obj->origin_path != NULL) 1231 return (true); 1232 obj->origin_path = xmalloc(PATH_MAX); 1233 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1234 } 1235 1236 static void 1237 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1238 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1239 { 1240 1241 if (obj->z_origin && !obj_resolve_origin(obj)) 1242 rtld_die(); 1243 1244 if (dyn_runpath != NULL) { 1245 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1246 obj->runpath = origin_subst(obj, obj->runpath); 1247 } else if (dyn_rpath != NULL) { 1248 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1249 obj->rpath = origin_subst(obj, obj->rpath); 1250 } 1251 if (dyn_soname != NULL) 1252 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1253 } 1254 1255 static void 1256 digest_dynamic(Obj_Entry *obj, int early) 1257 { 1258 const Elf_Dyn *dyn_rpath; 1259 const Elf_Dyn *dyn_soname; 1260 const Elf_Dyn *dyn_runpath; 1261 1262 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1263 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1264 } 1265 1266 /* 1267 * Process a shared object's program header. This is used only for the 1268 * main program, when the kernel has already loaded the main program 1269 * into memory before calling the dynamic linker. It creates and 1270 * returns an Obj_Entry structure. 1271 */ 1272 static Obj_Entry * 1273 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1274 { 1275 Obj_Entry *obj; 1276 const Elf_Phdr *phlimit = phdr + phnum; 1277 const Elf_Phdr *ph; 1278 Elf_Addr note_start, note_end; 1279 int nsegs = 0; 1280 1281 obj = obj_new(); 1282 for (ph = phdr; ph < phlimit; ph++) { 1283 if (ph->p_type != PT_PHDR) 1284 continue; 1285 1286 obj->phdr = phdr; 1287 obj->phsize = ph->p_memsz; 1288 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1289 break; 1290 } 1291 1292 obj->stack_flags = PF_X | PF_R | PF_W; 1293 1294 for (ph = phdr; ph < phlimit; ph++) { 1295 switch (ph->p_type) { 1296 1297 case PT_INTERP: 1298 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1299 break; 1300 1301 case PT_LOAD: 1302 if (nsegs == 0) { /* First load segment */ 1303 obj->vaddrbase = trunc_page(ph->p_vaddr); 1304 obj->mapbase = obj->vaddrbase + obj->relocbase; 1305 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1306 obj->vaddrbase; 1307 } else { /* Last load segment */ 1308 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1309 obj->vaddrbase; 1310 } 1311 nsegs++; 1312 break; 1313 1314 case PT_DYNAMIC: 1315 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1316 break; 1317 1318 case PT_TLS: 1319 obj->tlsindex = 1; 1320 obj->tlssize = ph->p_memsz; 1321 obj->tlsalign = ph->p_align; 1322 obj->tlsinitsize = ph->p_filesz; 1323 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1324 break; 1325 1326 case PT_GNU_STACK: 1327 obj->stack_flags = ph->p_flags; 1328 break; 1329 1330 case PT_GNU_RELRO: 1331 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1332 obj->relro_size = round_page(ph->p_memsz); 1333 break; 1334 1335 case PT_NOTE: 1336 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1337 note_end = note_start + ph->p_filesz; 1338 digest_notes(obj, note_start, note_end); 1339 break; 1340 } 1341 } 1342 if (nsegs < 1) { 1343 _rtld_error("%s: too few PT_LOAD segments", path); 1344 return NULL; 1345 } 1346 1347 obj->entry = entry; 1348 return obj; 1349 } 1350 1351 void 1352 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1353 { 1354 const Elf_Note *note; 1355 const char *note_name; 1356 uintptr_t p; 1357 1358 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1359 note = (const Elf_Note *)((const char *)(note + 1) + 1360 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1361 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1362 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1363 note->n_descsz != sizeof(int32_t)) 1364 continue; 1365 if (note->n_type != NT_FREEBSD_ABI_TAG && 1366 note->n_type != NT_FREEBSD_NOINIT_TAG) 1367 continue; 1368 note_name = (const char *)(note + 1); 1369 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1370 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1371 continue; 1372 switch (note->n_type) { 1373 case NT_FREEBSD_ABI_TAG: 1374 /* FreeBSD osrel note */ 1375 p = (uintptr_t)(note + 1); 1376 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1377 obj->osrel = *(const int32_t *)(p); 1378 dbg("note osrel %d", obj->osrel); 1379 break; 1380 case NT_FREEBSD_NOINIT_TAG: 1381 /* FreeBSD 'crt does not call init' note */ 1382 obj->crt_no_init = true; 1383 dbg("note crt_no_init"); 1384 break; 1385 } 1386 } 1387 } 1388 1389 static Obj_Entry * 1390 dlcheck(void *handle) 1391 { 1392 Obj_Entry *obj; 1393 1394 TAILQ_FOREACH(obj, &obj_list, next) { 1395 if (obj == (Obj_Entry *) handle) 1396 break; 1397 } 1398 1399 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1400 _rtld_error("Invalid shared object handle %p", handle); 1401 return NULL; 1402 } 1403 return obj; 1404 } 1405 1406 /* 1407 * If the given object is already in the donelist, return true. Otherwise 1408 * add the object to the list and return false. 1409 */ 1410 static bool 1411 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1412 { 1413 unsigned int i; 1414 1415 for (i = 0; i < dlp->num_used; i++) 1416 if (dlp->objs[i] == obj) 1417 return true; 1418 /* 1419 * Our donelist allocation should always be sufficient. But if 1420 * our threads locking isn't working properly, more shared objects 1421 * could have been loaded since we allocated the list. That should 1422 * never happen, but we'll handle it properly just in case it does. 1423 */ 1424 if (dlp->num_used < dlp->num_alloc) 1425 dlp->objs[dlp->num_used++] = obj; 1426 return false; 1427 } 1428 1429 /* 1430 * Hash function for symbol table lookup. Don't even think about changing 1431 * this. It is specified by the System V ABI. 1432 */ 1433 unsigned long 1434 elf_hash(const char *name) 1435 { 1436 const unsigned char *p = (const unsigned char *) name; 1437 unsigned long h = 0; 1438 unsigned long g; 1439 1440 while (*p != '\0') { 1441 h = (h << 4) + *p++; 1442 if ((g = h & 0xf0000000) != 0) 1443 h ^= g >> 24; 1444 h &= ~g; 1445 } 1446 return h; 1447 } 1448 1449 /* 1450 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1451 * unsigned in case it's implemented with a wider type. 1452 */ 1453 static uint32_t 1454 gnu_hash(const char *s) 1455 { 1456 uint32_t h; 1457 unsigned char c; 1458 1459 h = 5381; 1460 for (c = *s; c != '\0'; c = *++s) 1461 h = h * 33 + c; 1462 return (h & 0xffffffff); 1463 } 1464 1465 1466 /* 1467 * Find the library with the given name, and return its full pathname. 1468 * The returned string is dynamically allocated. Generates an error 1469 * message and returns NULL if the library cannot be found. 1470 * 1471 * If the second argument is non-NULL, then it refers to an already- 1472 * loaded shared object, whose library search path will be searched. 1473 * 1474 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1475 * descriptor (which is close-on-exec) will be passed out via the third 1476 * argument. 1477 * 1478 * The search order is: 1479 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1480 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1481 * LD_LIBRARY_PATH 1482 * DT_RUNPATH in the referencing file 1483 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1484 * from list) 1485 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1486 * 1487 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1488 */ 1489 static char * 1490 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1491 { 1492 char *pathname; 1493 char *name; 1494 bool nodeflib, objgiven; 1495 1496 objgiven = refobj != NULL; 1497 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1498 if (xname[0] != '/' && !trust) { 1499 _rtld_error("Absolute pathname required for shared object \"%s\"", 1500 xname); 1501 return NULL; 1502 } 1503 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1504 __DECONST(char *, xname))); 1505 } 1506 1507 if (libmap_disable || !objgiven || 1508 (name = lm_find(refobj->path, xname)) == NULL) 1509 name = (char *)xname; 1510 1511 dbg(" Searching for \"%s\"", name); 1512 1513 /* 1514 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1515 * back to pre-conforming behaviour if user requested so with 1516 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1517 * nodeflib. 1518 */ 1519 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1520 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1521 (refobj != NULL && 1522 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1523 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1524 (pathname = search_library_path(name, gethints(false))) != NULL || 1525 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1526 return (pathname); 1527 } else { 1528 nodeflib = objgiven ? refobj->z_nodeflib : false; 1529 if ((objgiven && 1530 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1531 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1532 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1533 (pathname = search_library_path(name, ld_library_path)) != NULL || 1534 (objgiven && 1535 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1536 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1537 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1538 (objgiven && !nodeflib && 1539 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1540 return (pathname); 1541 } 1542 1543 if (objgiven && refobj->path != NULL) { 1544 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1545 name, basename(refobj->path)); 1546 } else { 1547 _rtld_error("Shared object \"%s\" not found", name); 1548 } 1549 return NULL; 1550 } 1551 1552 /* 1553 * Given a symbol number in a referencing object, find the corresponding 1554 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1555 * no definition was found. Returns a pointer to the Obj_Entry of the 1556 * defining object via the reference parameter DEFOBJ_OUT. 1557 */ 1558 const Elf_Sym * 1559 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1560 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1561 RtldLockState *lockstate) 1562 { 1563 const Elf_Sym *ref; 1564 const Elf_Sym *def; 1565 const Obj_Entry *defobj; 1566 SymLook req; 1567 const char *name; 1568 int res; 1569 1570 /* 1571 * If we have already found this symbol, get the information from 1572 * the cache. 1573 */ 1574 if (symnum >= refobj->dynsymcount) 1575 return NULL; /* Bad object */ 1576 if (cache != NULL && cache[symnum].sym != NULL) { 1577 *defobj_out = cache[symnum].obj; 1578 return cache[symnum].sym; 1579 } 1580 1581 ref = refobj->symtab + symnum; 1582 name = refobj->strtab + ref->st_name; 1583 def = NULL; 1584 defobj = NULL; 1585 1586 /* 1587 * We don't have to do a full scale lookup if the symbol is local. 1588 * We know it will bind to the instance in this load module; to 1589 * which we already have a pointer (ie ref). By not doing a lookup, 1590 * we not only improve performance, but it also avoids unresolvable 1591 * symbols when local symbols are not in the hash table. This has 1592 * been seen with the ia64 toolchain. 1593 */ 1594 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1595 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1596 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1597 symnum); 1598 } 1599 symlook_init(&req, name); 1600 req.flags = flags; 1601 req.ventry = fetch_ventry(refobj, symnum); 1602 req.lockstate = lockstate; 1603 res = symlook_default(&req, refobj); 1604 if (res == 0) { 1605 def = req.sym_out; 1606 defobj = req.defobj_out; 1607 } 1608 } else { 1609 def = ref; 1610 defobj = refobj; 1611 } 1612 1613 /* 1614 * If we found no definition and the reference is weak, treat the 1615 * symbol as having the value zero. 1616 */ 1617 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1618 def = &sym_zero; 1619 defobj = obj_main; 1620 } 1621 1622 if (def != NULL) { 1623 *defobj_out = defobj; 1624 /* Record the information in the cache to avoid subsequent lookups. */ 1625 if (cache != NULL) { 1626 cache[symnum].sym = def; 1627 cache[symnum].obj = defobj; 1628 } 1629 } else { 1630 if (refobj != &obj_rtld) 1631 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1632 } 1633 return def; 1634 } 1635 1636 /* 1637 * Return the search path from the ldconfig hints file, reading it if 1638 * necessary. If nostdlib is true, then the default search paths are 1639 * not added to result. 1640 * 1641 * Returns NULL if there are problems with the hints file, 1642 * or if the search path there is empty. 1643 */ 1644 static const char * 1645 gethints(bool nostdlib) 1646 { 1647 static char *hints, *filtered_path; 1648 static struct elfhints_hdr hdr; 1649 struct fill_search_info_args sargs, hargs; 1650 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1651 struct dl_serpath *SLPpath, *hintpath; 1652 char *p; 1653 struct stat hint_stat; 1654 unsigned int SLPndx, hintndx, fndx, fcount; 1655 int fd; 1656 size_t flen; 1657 uint32_t dl; 1658 bool skip; 1659 1660 /* First call, read the hints file */ 1661 if (hints == NULL) { 1662 /* Keep from trying again in case the hints file is bad. */ 1663 hints = ""; 1664 1665 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1666 return (NULL); 1667 1668 /* 1669 * Check of hdr.dirlistlen value against type limit 1670 * intends to pacify static analyzers. Further 1671 * paranoia leads to checks that dirlist is fully 1672 * contained in the file range. 1673 */ 1674 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1675 hdr.magic != ELFHINTS_MAGIC || 1676 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1677 fstat(fd, &hint_stat) == -1) { 1678 cleanup1: 1679 close(fd); 1680 hdr.dirlistlen = 0; 1681 return (NULL); 1682 } 1683 dl = hdr.strtab; 1684 if (dl + hdr.dirlist < dl) 1685 goto cleanup1; 1686 dl += hdr.dirlist; 1687 if (dl + hdr.dirlistlen < dl) 1688 goto cleanup1; 1689 dl += hdr.dirlistlen; 1690 if (dl > hint_stat.st_size) 1691 goto cleanup1; 1692 p = xmalloc(hdr.dirlistlen + 1); 1693 1694 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1695 read(fd, p, hdr.dirlistlen + 1) != 1696 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1697 free(p); 1698 goto cleanup1; 1699 } 1700 hints = p; 1701 close(fd); 1702 } 1703 1704 /* 1705 * If caller agreed to receive list which includes the default 1706 * paths, we are done. Otherwise, if we still did not 1707 * calculated filtered result, do it now. 1708 */ 1709 if (!nostdlib) 1710 return (hints[0] != '\0' ? hints : NULL); 1711 if (filtered_path != NULL) 1712 goto filt_ret; 1713 1714 /* 1715 * Obtain the list of all configured search paths, and the 1716 * list of the default paths. 1717 * 1718 * First estimate the size of the results. 1719 */ 1720 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1721 smeta.dls_cnt = 0; 1722 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1723 hmeta.dls_cnt = 0; 1724 1725 sargs.request = RTLD_DI_SERINFOSIZE; 1726 sargs.serinfo = &smeta; 1727 hargs.request = RTLD_DI_SERINFOSIZE; 1728 hargs.serinfo = &hmeta; 1729 1730 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1731 path_enumerate(hints, fill_search_info, &hargs); 1732 1733 SLPinfo = xmalloc(smeta.dls_size); 1734 hintinfo = xmalloc(hmeta.dls_size); 1735 1736 /* 1737 * Next fetch both sets of paths. 1738 */ 1739 sargs.request = RTLD_DI_SERINFO; 1740 sargs.serinfo = SLPinfo; 1741 sargs.serpath = &SLPinfo->dls_serpath[0]; 1742 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1743 1744 hargs.request = RTLD_DI_SERINFO; 1745 hargs.serinfo = hintinfo; 1746 hargs.serpath = &hintinfo->dls_serpath[0]; 1747 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1748 1749 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1750 path_enumerate(hints, fill_search_info, &hargs); 1751 1752 /* 1753 * Now calculate the difference between two sets, by excluding 1754 * standard paths from the full set. 1755 */ 1756 fndx = 0; 1757 fcount = 0; 1758 filtered_path = xmalloc(hdr.dirlistlen + 1); 1759 hintpath = &hintinfo->dls_serpath[0]; 1760 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1761 skip = false; 1762 SLPpath = &SLPinfo->dls_serpath[0]; 1763 /* 1764 * Check each standard path against current. 1765 */ 1766 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1767 /* matched, skip the path */ 1768 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1769 skip = true; 1770 break; 1771 } 1772 } 1773 if (skip) 1774 continue; 1775 /* 1776 * Not matched against any standard path, add the path 1777 * to result. Separate consequtive paths with ':'. 1778 */ 1779 if (fcount > 0) { 1780 filtered_path[fndx] = ':'; 1781 fndx++; 1782 } 1783 fcount++; 1784 flen = strlen(hintpath->dls_name); 1785 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1786 fndx += flen; 1787 } 1788 filtered_path[fndx] = '\0'; 1789 1790 free(SLPinfo); 1791 free(hintinfo); 1792 1793 filt_ret: 1794 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1795 } 1796 1797 static void 1798 init_dag(Obj_Entry *root) 1799 { 1800 const Needed_Entry *needed; 1801 const Objlist_Entry *elm; 1802 DoneList donelist; 1803 1804 if (root->dag_inited) 1805 return; 1806 donelist_init(&donelist); 1807 1808 /* Root object belongs to own DAG. */ 1809 objlist_push_tail(&root->dldags, root); 1810 objlist_push_tail(&root->dagmembers, root); 1811 donelist_check(&donelist, root); 1812 1813 /* 1814 * Add dependencies of root object to DAG in breadth order 1815 * by exploiting the fact that each new object get added 1816 * to the tail of the dagmembers list. 1817 */ 1818 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1819 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1820 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1821 continue; 1822 objlist_push_tail(&needed->obj->dldags, root); 1823 objlist_push_tail(&root->dagmembers, needed->obj); 1824 } 1825 } 1826 root->dag_inited = true; 1827 } 1828 1829 Obj_Entry * 1830 globallist_curr(const Obj_Entry *obj) 1831 { 1832 1833 for (;;) { 1834 if (obj == NULL) 1835 return (NULL); 1836 if (!obj->marker) 1837 return (__DECONST(Obj_Entry *, obj)); 1838 obj = TAILQ_PREV(obj, obj_entry_q, next); 1839 } 1840 } 1841 1842 Obj_Entry * 1843 globallist_next(const Obj_Entry *obj) 1844 { 1845 1846 for (;;) { 1847 obj = TAILQ_NEXT(obj, next); 1848 if (obj == NULL) 1849 return (NULL); 1850 if (!obj->marker) 1851 return (__DECONST(Obj_Entry *, obj)); 1852 } 1853 } 1854 1855 static void 1856 process_z(Obj_Entry *root) 1857 { 1858 const Objlist_Entry *elm; 1859 Obj_Entry *obj; 1860 1861 /* 1862 * Walk over object DAG and process every dependent object 1863 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1864 * to grow their own DAG. 1865 * 1866 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1867 * symlook_global() to work. 1868 * 1869 * For DF_1_NODELETE, the DAG should have its reference upped. 1870 */ 1871 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1872 obj = elm->obj; 1873 if (obj == NULL) 1874 continue; 1875 if (obj->z_nodelete && !obj->ref_nodel) { 1876 dbg("obj %s -z nodelete", obj->path); 1877 init_dag(obj); 1878 ref_dag(obj); 1879 obj->ref_nodel = true; 1880 } 1881 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1882 dbg("obj %s -z global", obj->path); 1883 objlist_push_tail(&list_global, obj); 1884 init_dag(obj); 1885 } 1886 } 1887 } 1888 /* 1889 * Initialize the dynamic linker. The argument is the address at which 1890 * the dynamic linker has been mapped into memory. The primary task of 1891 * this function is to relocate the dynamic linker. 1892 */ 1893 static void 1894 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1895 { 1896 Obj_Entry objtmp; /* Temporary rtld object */ 1897 const Elf_Ehdr *ehdr; 1898 const Elf_Dyn *dyn_rpath; 1899 const Elf_Dyn *dyn_soname; 1900 const Elf_Dyn *dyn_runpath; 1901 1902 #ifdef RTLD_INIT_PAGESIZES_EARLY 1903 /* The page size is required by the dynamic memory allocator. */ 1904 init_pagesizes(aux_info); 1905 #endif 1906 1907 /* 1908 * Conjure up an Obj_Entry structure for the dynamic linker. 1909 * 1910 * The "path" member can't be initialized yet because string constants 1911 * cannot yet be accessed. Below we will set it correctly. 1912 */ 1913 memset(&objtmp, 0, sizeof(objtmp)); 1914 objtmp.path = NULL; 1915 objtmp.rtld = true; 1916 objtmp.mapbase = mapbase; 1917 #ifdef PIC 1918 objtmp.relocbase = mapbase; 1919 #endif 1920 1921 objtmp.dynamic = rtld_dynamic(&objtmp); 1922 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1923 assert(objtmp.needed == NULL); 1924 #if !defined(__mips__) 1925 /* MIPS has a bogus DT_TEXTREL. */ 1926 assert(!objtmp.textrel); 1927 #endif 1928 /* 1929 * Temporarily put the dynamic linker entry into the object list, so 1930 * that symbols can be found. 1931 */ 1932 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1933 1934 ehdr = (Elf_Ehdr *)mapbase; 1935 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1936 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1937 1938 /* Initialize the object list. */ 1939 TAILQ_INIT(&obj_list); 1940 1941 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1942 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1943 1944 #ifndef RTLD_INIT_PAGESIZES_EARLY 1945 /* The page size is required by the dynamic memory allocator. */ 1946 init_pagesizes(aux_info); 1947 #endif 1948 1949 if (aux_info[AT_OSRELDATE] != NULL) 1950 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1951 1952 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1953 1954 /* Replace the path with a dynamically allocated copy. */ 1955 obj_rtld.path = xstrdup(ld_path_rtld); 1956 1957 r_debug.r_brk = r_debug_state; 1958 r_debug.r_state = RT_CONSISTENT; 1959 } 1960 1961 /* 1962 * Retrieve the array of supported page sizes. The kernel provides the page 1963 * sizes in increasing order. 1964 */ 1965 static void 1966 init_pagesizes(Elf_Auxinfo **aux_info) 1967 { 1968 static size_t psa[MAXPAGESIZES]; 1969 int mib[2]; 1970 size_t len, size; 1971 1972 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1973 NULL) { 1974 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1975 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1976 } else { 1977 len = 2; 1978 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1979 size = sizeof(psa); 1980 else { 1981 /* As a fallback, retrieve the base page size. */ 1982 size = sizeof(psa[0]); 1983 if (aux_info[AT_PAGESZ] != NULL) { 1984 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1985 goto psa_filled; 1986 } else { 1987 mib[0] = CTL_HW; 1988 mib[1] = HW_PAGESIZE; 1989 len = 2; 1990 } 1991 } 1992 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1993 _rtld_error("sysctl for hw.pagesize(s) failed"); 1994 rtld_die(); 1995 } 1996 psa_filled: 1997 pagesizes = psa; 1998 } 1999 npagesizes = size / sizeof(pagesizes[0]); 2000 /* Discard any invalid entries at the end of the array. */ 2001 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2002 npagesizes--; 2003 } 2004 2005 /* 2006 * Add the init functions from a needed object list (and its recursive 2007 * needed objects) to "list". This is not used directly; it is a helper 2008 * function for initlist_add_objects(). The write lock must be held 2009 * when this function is called. 2010 */ 2011 static void 2012 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2013 { 2014 /* Recursively process the successor needed objects. */ 2015 if (needed->next != NULL) 2016 initlist_add_neededs(needed->next, list); 2017 2018 /* Process the current needed object. */ 2019 if (needed->obj != NULL) 2020 initlist_add_objects(needed->obj, needed->obj, list); 2021 } 2022 2023 /* 2024 * Scan all of the DAGs rooted in the range of objects from "obj" to 2025 * "tail" and add their init functions to "list". This recurses over 2026 * the DAGs and ensure the proper init ordering such that each object's 2027 * needed libraries are initialized before the object itself. At the 2028 * same time, this function adds the objects to the global finalization 2029 * list "list_fini" in the opposite order. The write lock must be 2030 * held when this function is called. 2031 */ 2032 static void 2033 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2034 { 2035 Obj_Entry *nobj; 2036 2037 if (obj->init_scanned || obj->init_done) 2038 return; 2039 obj->init_scanned = true; 2040 2041 /* Recursively process the successor objects. */ 2042 nobj = globallist_next(obj); 2043 if (nobj != NULL && obj != tail) 2044 initlist_add_objects(nobj, tail, list); 2045 2046 /* Recursively process the needed objects. */ 2047 if (obj->needed != NULL) 2048 initlist_add_neededs(obj->needed, list); 2049 if (obj->needed_filtees != NULL) 2050 initlist_add_neededs(obj->needed_filtees, list); 2051 if (obj->needed_aux_filtees != NULL) 2052 initlist_add_neededs(obj->needed_aux_filtees, list); 2053 2054 /* Add the object to the init list. */ 2055 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2056 obj->init_array != (Elf_Addr)NULL) 2057 objlist_push_tail(list, obj); 2058 2059 /* Add the object to the global fini list in the reverse order. */ 2060 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2061 && !obj->on_fini_list) { 2062 objlist_push_head(&list_fini, obj); 2063 obj->on_fini_list = true; 2064 } 2065 } 2066 2067 #ifndef FPTR_TARGET 2068 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2069 #endif 2070 2071 static void 2072 free_needed_filtees(Needed_Entry *n) 2073 { 2074 Needed_Entry *needed, *needed1; 2075 2076 for (needed = n; needed != NULL; needed = needed->next) { 2077 if (needed->obj != NULL) { 2078 dlclose(needed->obj); 2079 needed->obj = NULL; 2080 } 2081 } 2082 for (needed = n; needed != NULL; needed = needed1) { 2083 needed1 = needed->next; 2084 free(needed); 2085 } 2086 } 2087 2088 static void 2089 unload_filtees(Obj_Entry *obj) 2090 { 2091 2092 free_needed_filtees(obj->needed_filtees); 2093 obj->needed_filtees = NULL; 2094 free_needed_filtees(obj->needed_aux_filtees); 2095 obj->needed_aux_filtees = NULL; 2096 obj->filtees_loaded = false; 2097 } 2098 2099 static void 2100 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2101 RtldLockState *lockstate) 2102 { 2103 2104 for (; needed != NULL; needed = needed->next) { 2105 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2106 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2107 RTLD_LOCAL, lockstate); 2108 } 2109 } 2110 2111 static void 2112 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2113 { 2114 2115 lock_restart_for_upgrade(lockstate); 2116 if (!obj->filtees_loaded) { 2117 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2118 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2119 obj->filtees_loaded = true; 2120 } 2121 } 2122 2123 static int 2124 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2125 { 2126 Obj_Entry *obj1; 2127 2128 for (; needed != NULL; needed = needed->next) { 2129 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2130 flags & ~RTLD_LO_NOLOAD); 2131 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2132 return (-1); 2133 } 2134 return (0); 2135 } 2136 2137 /* 2138 * Given a shared object, traverse its list of needed objects, and load 2139 * each of them. Returns 0 on success. Generates an error message and 2140 * returns -1 on failure. 2141 */ 2142 static int 2143 load_needed_objects(Obj_Entry *first, int flags) 2144 { 2145 Obj_Entry *obj; 2146 2147 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2148 if (obj->marker) 2149 continue; 2150 if (process_needed(obj, obj->needed, flags) == -1) 2151 return (-1); 2152 } 2153 return (0); 2154 } 2155 2156 static int 2157 load_preload_objects(void) 2158 { 2159 char *p = ld_preload; 2160 Obj_Entry *obj; 2161 static const char delim[] = " \t:;"; 2162 2163 if (p == NULL) 2164 return 0; 2165 2166 p += strspn(p, delim); 2167 while (*p != '\0') { 2168 size_t len = strcspn(p, delim); 2169 char savech; 2170 2171 savech = p[len]; 2172 p[len] = '\0'; 2173 obj = load_object(p, -1, NULL, 0); 2174 if (obj == NULL) 2175 return -1; /* XXX - cleanup */ 2176 obj->z_interpose = true; 2177 p[len] = savech; 2178 p += len; 2179 p += strspn(p, delim); 2180 } 2181 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2182 return 0; 2183 } 2184 2185 static const char * 2186 printable_path(const char *path) 2187 { 2188 2189 return (path == NULL ? "<unknown>" : path); 2190 } 2191 2192 /* 2193 * Load a shared object into memory, if it is not already loaded. The 2194 * object may be specified by name or by user-supplied file descriptor 2195 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2196 * duplicate is. 2197 * 2198 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2199 * on failure. 2200 */ 2201 static Obj_Entry * 2202 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2203 { 2204 Obj_Entry *obj; 2205 int fd; 2206 struct stat sb; 2207 char *path; 2208 2209 fd = -1; 2210 if (name != NULL) { 2211 TAILQ_FOREACH(obj, &obj_list, next) { 2212 if (obj->marker) 2213 continue; 2214 if (object_match_name(obj, name)) 2215 return (obj); 2216 } 2217 2218 path = find_library(name, refobj, &fd); 2219 if (path == NULL) 2220 return (NULL); 2221 } else 2222 path = NULL; 2223 2224 if (fd >= 0) { 2225 /* 2226 * search_library_pathfds() opens a fresh file descriptor for the 2227 * library, so there is no need to dup(). 2228 */ 2229 } else if (fd_u == -1) { 2230 /* 2231 * If we didn't find a match by pathname, or the name is not 2232 * supplied, open the file and check again by device and inode. 2233 * This avoids false mismatches caused by multiple links or ".." 2234 * in pathnames. 2235 * 2236 * To avoid a race, we open the file and use fstat() rather than 2237 * using stat(). 2238 */ 2239 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2240 _rtld_error("Cannot open \"%s\"", path); 2241 free(path); 2242 return (NULL); 2243 } 2244 } else { 2245 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2246 if (fd == -1) { 2247 _rtld_error("Cannot dup fd"); 2248 free(path); 2249 return (NULL); 2250 } 2251 } 2252 if (fstat(fd, &sb) == -1) { 2253 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2254 close(fd); 2255 free(path); 2256 return NULL; 2257 } 2258 TAILQ_FOREACH(obj, &obj_list, next) { 2259 if (obj->marker) 2260 continue; 2261 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2262 break; 2263 } 2264 if (obj != NULL && name != NULL) { 2265 object_add_name(obj, name); 2266 free(path); 2267 close(fd); 2268 return obj; 2269 } 2270 if (flags & RTLD_LO_NOLOAD) { 2271 free(path); 2272 close(fd); 2273 return (NULL); 2274 } 2275 2276 /* First use of this object, so we must map it in */ 2277 obj = do_load_object(fd, name, path, &sb, flags); 2278 if (obj == NULL) 2279 free(path); 2280 close(fd); 2281 2282 return obj; 2283 } 2284 2285 static Obj_Entry * 2286 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2287 int flags) 2288 { 2289 Obj_Entry *obj; 2290 struct statfs fs; 2291 2292 /* 2293 * but first, make sure that environment variables haven't been 2294 * used to circumvent the noexec flag on a filesystem. 2295 */ 2296 if (dangerous_ld_env) { 2297 if (fstatfs(fd, &fs) != 0) { 2298 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2299 return NULL; 2300 } 2301 if (fs.f_flags & MNT_NOEXEC) { 2302 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2303 return NULL; 2304 } 2305 } 2306 dbg("loading \"%s\"", printable_path(path)); 2307 obj = map_object(fd, printable_path(path), sbp); 2308 if (obj == NULL) 2309 return NULL; 2310 2311 /* 2312 * If DT_SONAME is present in the object, digest_dynamic2 already 2313 * added it to the object names. 2314 */ 2315 if (name != NULL) 2316 object_add_name(obj, name); 2317 obj->path = path; 2318 digest_dynamic(obj, 0); 2319 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2320 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2321 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2322 RTLD_LO_DLOPEN) { 2323 dbg("refusing to load non-loadable \"%s\"", obj->path); 2324 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2325 munmap(obj->mapbase, obj->mapsize); 2326 obj_free(obj); 2327 return (NULL); 2328 } 2329 2330 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2331 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2332 obj_count++; 2333 obj_loads++; 2334 linkmap_add(obj); /* for GDB & dlinfo() */ 2335 max_stack_flags |= obj->stack_flags; 2336 2337 dbg(" %p .. %p: %s", obj->mapbase, 2338 obj->mapbase + obj->mapsize - 1, obj->path); 2339 if (obj->textrel) 2340 dbg(" WARNING: %s has impure text", obj->path); 2341 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2342 obj->path); 2343 2344 return obj; 2345 } 2346 2347 static Obj_Entry * 2348 obj_from_addr(const void *addr) 2349 { 2350 Obj_Entry *obj; 2351 2352 TAILQ_FOREACH(obj, &obj_list, next) { 2353 if (obj->marker) 2354 continue; 2355 if (addr < (void *) obj->mapbase) 2356 continue; 2357 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2358 return obj; 2359 } 2360 return NULL; 2361 } 2362 2363 static void 2364 preinit_main(void) 2365 { 2366 Elf_Addr *preinit_addr; 2367 int index; 2368 2369 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2370 if (preinit_addr == NULL) 2371 return; 2372 2373 for (index = 0; index < obj_main->preinit_array_num; index++) { 2374 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2375 dbg("calling preinit function for %s at %p", obj_main->path, 2376 (void *)preinit_addr[index]); 2377 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2378 0, 0, obj_main->path); 2379 call_init_pointer(obj_main, preinit_addr[index]); 2380 } 2381 } 2382 } 2383 2384 /* 2385 * Call the finalization functions for each of the objects in "list" 2386 * belonging to the DAG of "root" and referenced once. If NULL "root" 2387 * is specified, every finalization function will be called regardless 2388 * of the reference count and the list elements won't be freed. All of 2389 * the objects are expected to have non-NULL fini functions. 2390 */ 2391 static void 2392 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2393 { 2394 Objlist_Entry *elm; 2395 char *saved_msg; 2396 Elf_Addr *fini_addr; 2397 int index; 2398 2399 assert(root == NULL || root->refcount == 1); 2400 2401 /* 2402 * Preserve the current error message since a fini function might 2403 * call into the dynamic linker and overwrite it. 2404 */ 2405 saved_msg = errmsg_save(); 2406 do { 2407 STAILQ_FOREACH(elm, list, link) { 2408 if (root != NULL && (elm->obj->refcount != 1 || 2409 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2410 continue; 2411 /* Remove object from fini list to prevent recursive invocation. */ 2412 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2413 /* 2414 * XXX: If a dlopen() call references an object while the 2415 * fini function is in progress, we might end up trying to 2416 * unload the referenced object in dlclose() or the object 2417 * won't be unloaded although its fini function has been 2418 * called. 2419 */ 2420 lock_release(rtld_bind_lock, lockstate); 2421 2422 /* 2423 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2424 * When this happens, DT_FINI_ARRAY is processed first. 2425 */ 2426 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2427 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2428 for (index = elm->obj->fini_array_num - 1; index >= 0; 2429 index--) { 2430 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2431 dbg("calling fini function for %s at %p", 2432 elm->obj->path, (void *)fini_addr[index]); 2433 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2434 (void *)fini_addr[index], 0, 0, elm->obj->path); 2435 call_initfini_pointer(elm->obj, fini_addr[index]); 2436 } 2437 } 2438 } 2439 if (elm->obj->fini != (Elf_Addr)NULL) { 2440 dbg("calling fini function for %s at %p", elm->obj->path, 2441 (void *)elm->obj->fini); 2442 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2443 0, 0, elm->obj->path); 2444 call_initfini_pointer(elm->obj, elm->obj->fini); 2445 } 2446 wlock_acquire(rtld_bind_lock, lockstate); 2447 /* No need to free anything if process is going down. */ 2448 if (root != NULL) 2449 free(elm); 2450 /* 2451 * We must restart the list traversal after every fini call 2452 * because a dlclose() call from the fini function or from 2453 * another thread might have modified the reference counts. 2454 */ 2455 break; 2456 } 2457 } while (elm != NULL); 2458 errmsg_restore(saved_msg); 2459 } 2460 2461 /* 2462 * Call the initialization functions for each of the objects in 2463 * "list". All of the objects are expected to have non-NULL init 2464 * functions. 2465 */ 2466 static void 2467 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2468 { 2469 Objlist_Entry *elm; 2470 Obj_Entry *obj; 2471 char *saved_msg; 2472 Elf_Addr *init_addr; 2473 int index; 2474 2475 /* 2476 * Clean init_scanned flag so that objects can be rechecked and 2477 * possibly initialized earlier if any of vectors called below 2478 * cause the change by using dlopen. 2479 */ 2480 TAILQ_FOREACH(obj, &obj_list, next) { 2481 if (obj->marker) 2482 continue; 2483 obj->init_scanned = false; 2484 } 2485 2486 /* 2487 * Preserve the current error message since an init function might 2488 * call into the dynamic linker and overwrite it. 2489 */ 2490 saved_msg = errmsg_save(); 2491 STAILQ_FOREACH(elm, list, link) { 2492 if (elm->obj->init_done) /* Initialized early. */ 2493 continue; 2494 /* 2495 * Race: other thread might try to use this object before current 2496 * one completes the initilization. Not much can be done here 2497 * without better locking. 2498 */ 2499 elm->obj->init_done = true; 2500 lock_release(rtld_bind_lock, lockstate); 2501 2502 /* 2503 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2504 * When this happens, DT_INIT is processed first. 2505 */ 2506 if (elm->obj->init != (Elf_Addr)NULL) { 2507 dbg("calling init function for %s at %p", elm->obj->path, 2508 (void *)elm->obj->init); 2509 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2510 0, 0, elm->obj->path); 2511 call_initfini_pointer(elm->obj, elm->obj->init); 2512 } 2513 init_addr = (Elf_Addr *)elm->obj->init_array; 2514 if (init_addr != NULL) { 2515 for (index = 0; index < elm->obj->init_array_num; index++) { 2516 if (init_addr[index] != 0 && init_addr[index] != 1) { 2517 dbg("calling init function for %s at %p", elm->obj->path, 2518 (void *)init_addr[index]); 2519 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2520 (void *)init_addr[index], 0, 0, elm->obj->path); 2521 call_init_pointer(elm->obj, init_addr[index]); 2522 } 2523 } 2524 } 2525 wlock_acquire(rtld_bind_lock, lockstate); 2526 } 2527 errmsg_restore(saved_msg); 2528 } 2529 2530 static void 2531 objlist_clear(Objlist *list) 2532 { 2533 Objlist_Entry *elm; 2534 2535 while (!STAILQ_EMPTY(list)) { 2536 elm = STAILQ_FIRST(list); 2537 STAILQ_REMOVE_HEAD(list, link); 2538 free(elm); 2539 } 2540 } 2541 2542 static Objlist_Entry * 2543 objlist_find(Objlist *list, const Obj_Entry *obj) 2544 { 2545 Objlist_Entry *elm; 2546 2547 STAILQ_FOREACH(elm, list, link) 2548 if (elm->obj == obj) 2549 return elm; 2550 return NULL; 2551 } 2552 2553 static void 2554 objlist_init(Objlist *list) 2555 { 2556 STAILQ_INIT(list); 2557 } 2558 2559 static void 2560 objlist_push_head(Objlist *list, Obj_Entry *obj) 2561 { 2562 Objlist_Entry *elm; 2563 2564 elm = NEW(Objlist_Entry); 2565 elm->obj = obj; 2566 STAILQ_INSERT_HEAD(list, elm, link); 2567 } 2568 2569 static void 2570 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2571 { 2572 Objlist_Entry *elm; 2573 2574 elm = NEW(Objlist_Entry); 2575 elm->obj = obj; 2576 STAILQ_INSERT_TAIL(list, elm, link); 2577 } 2578 2579 static void 2580 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2581 { 2582 Objlist_Entry *elm, *listelm; 2583 2584 STAILQ_FOREACH(listelm, list, link) { 2585 if (listelm->obj == listobj) 2586 break; 2587 } 2588 elm = NEW(Objlist_Entry); 2589 elm->obj = obj; 2590 if (listelm != NULL) 2591 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2592 else 2593 STAILQ_INSERT_TAIL(list, elm, link); 2594 } 2595 2596 static void 2597 objlist_remove(Objlist *list, Obj_Entry *obj) 2598 { 2599 Objlist_Entry *elm; 2600 2601 if ((elm = objlist_find(list, obj)) != NULL) { 2602 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2603 free(elm); 2604 } 2605 } 2606 2607 /* 2608 * Relocate dag rooted in the specified object. 2609 * Returns 0 on success, or -1 on failure. 2610 */ 2611 2612 static int 2613 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2614 int flags, RtldLockState *lockstate) 2615 { 2616 Objlist_Entry *elm; 2617 int error; 2618 2619 error = 0; 2620 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2621 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2622 lockstate); 2623 if (error == -1) 2624 break; 2625 } 2626 return (error); 2627 } 2628 2629 /* 2630 * Prepare for, or clean after, relocating an object marked with 2631 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2632 * segments are remapped read-write. After relocations are done, the 2633 * segment's permissions are returned back to the modes specified in 2634 * the phdrs. If any relocation happened, or always for wired 2635 * program, COW is triggered. 2636 */ 2637 static int 2638 reloc_textrel_prot(Obj_Entry *obj, bool before) 2639 { 2640 const Elf_Phdr *ph; 2641 void *base; 2642 size_t l, sz; 2643 int prot; 2644 2645 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2646 l--, ph++) { 2647 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2648 continue; 2649 base = obj->relocbase + trunc_page(ph->p_vaddr); 2650 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2651 trunc_page(ph->p_vaddr); 2652 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2653 if (mprotect(base, sz, prot) == -1) { 2654 _rtld_error("%s: Cannot write-%sable text segment: %s", 2655 obj->path, before ? "en" : "dis", 2656 rtld_strerror(errno)); 2657 return (-1); 2658 } 2659 } 2660 return (0); 2661 } 2662 2663 /* 2664 * Relocate single object. 2665 * Returns 0 on success, or -1 on failure. 2666 */ 2667 static int 2668 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2669 int flags, RtldLockState *lockstate) 2670 { 2671 2672 if (obj->relocated) 2673 return (0); 2674 obj->relocated = true; 2675 if (obj != rtldobj) 2676 dbg("relocating \"%s\"", obj->path); 2677 2678 if (obj->symtab == NULL || obj->strtab == NULL || 2679 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2680 _rtld_error("%s: Shared object has no run-time symbol table", 2681 obj->path); 2682 return (-1); 2683 } 2684 2685 /* There are relocations to the write-protected text segment. */ 2686 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2687 return (-1); 2688 2689 /* Process the non-PLT non-IFUNC relocations. */ 2690 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2691 return (-1); 2692 2693 /* Re-protected the text segment. */ 2694 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2695 return (-1); 2696 2697 /* Set the special PLT or GOT entries. */ 2698 init_pltgot(obj); 2699 2700 /* Process the PLT relocations. */ 2701 if (reloc_plt(obj) == -1) 2702 return (-1); 2703 /* Relocate the jump slots if we are doing immediate binding. */ 2704 if (obj->bind_now || bind_now) 2705 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2706 return (-1); 2707 2708 /* 2709 * Process the non-PLT IFUNC relocations. The relocations are 2710 * processed in two phases, because IFUNC resolvers may 2711 * reference other symbols, which must be readily processed 2712 * before resolvers are called. 2713 */ 2714 if (obj->non_plt_gnu_ifunc && 2715 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2716 return (-1); 2717 2718 if (obj->relro_size > 0) { 2719 if (mprotect(obj->relro_page, obj->relro_size, 2720 PROT_READ) == -1) { 2721 _rtld_error("%s: Cannot enforce relro protection: %s", 2722 obj->path, rtld_strerror(errno)); 2723 return (-1); 2724 } 2725 } 2726 2727 /* 2728 * Set up the magic number and version in the Obj_Entry. These 2729 * were checked in the crt1.o from the original ElfKit, so we 2730 * set them for backward compatibility. 2731 */ 2732 obj->magic = RTLD_MAGIC; 2733 obj->version = RTLD_VERSION; 2734 2735 return (0); 2736 } 2737 2738 /* 2739 * Relocate newly-loaded shared objects. The argument is a pointer to 2740 * the Obj_Entry for the first such object. All objects from the first 2741 * to the end of the list of objects are relocated. Returns 0 on success, 2742 * or -1 on failure. 2743 */ 2744 static int 2745 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2746 int flags, RtldLockState *lockstate) 2747 { 2748 Obj_Entry *obj; 2749 int error; 2750 2751 for (error = 0, obj = first; obj != NULL; 2752 obj = TAILQ_NEXT(obj, next)) { 2753 if (obj->marker) 2754 continue; 2755 error = relocate_object(obj, bind_now, rtldobj, flags, 2756 lockstate); 2757 if (error == -1) 2758 break; 2759 } 2760 return (error); 2761 } 2762 2763 /* 2764 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2765 * referencing STT_GNU_IFUNC symbols is postponed till the other 2766 * relocations are done. The indirect functions specified as 2767 * ifunc are allowed to call other symbols, so we need to have 2768 * objects relocated before asking for resolution from indirects. 2769 * 2770 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2771 * instead of the usual lazy handling of PLT slots. It is 2772 * consistent with how GNU does it. 2773 */ 2774 static int 2775 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2776 RtldLockState *lockstate) 2777 { 2778 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2779 return (-1); 2780 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2781 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2782 return (-1); 2783 return (0); 2784 } 2785 2786 static int 2787 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2788 RtldLockState *lockstate) 2789 { 2790 Obj_Entry *obj; 2791 2792 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2793 if (obj->marker) 2794 continue; 2795 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2796 return (-1); 2797 } 2798 return (0); 2799 } 2800 2801 static int 2802 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2803 RtldLockState *lockstate) 2804 { 2805 Objlist_Entry *elm; 2806 2807 STAILQ_FOREACH(elm, list, link) { 2808 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2809 lockstate) == -1) 2810 return (-1); 2811 } 2812 return (0); 2813 } 2814 2815 /* 2816 * Cleanup procedure. It will be called (by the atexit mechanism) just 2817 * before the process exits. 2818 */ 2819 static void 2820 rtld_exit(void) 2821 { 2822 RtldLockState lockstate; 2823 2824 wlock_acquire(rtld_bind_lock, &lockstate); 2825 dbg("rtld_exit()"); 2826 objlist_call_fini(&list_fini, NULL, &lockstate); 2827 /* No need to remove the items from the list, since we are exiting. */ 2828 if (!libmap_disable) 2829 lm_fini(); 2830 lock_release(rtld_bind_lock, &lockstate); 2831 } 2832 2833 /* 2834 * Iterate over a search path, translate each element, and invoke the 2835 * callback on the result. 2836 */ 2837 static void * 2838 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2839 { 2840 const char *trans; 2841 if (path == NULL) 2842 return (NULL); 2843 2844 path += strspn(path, ":;"); 2845 while (*path != '\0') { 2846 size_t len; 2847 char *res; 2848 2849 len = strcspn(path, ":;"); 2850 trans = lm_findn(NULL, path, len); 2851 if (trans) 2852 res = callback(trans, strlen(trans), arg); 2853 else 2854 res = callback(path, len, arg); 2855 2856 if (res != NULL) 2857 return (res); 2858 2859 path += len; 2860 path += strspn(path, ":;"); 2861 } 2862 2863 return (NULL); 2864 } 2865 2866 struct try_library_args { 2867 const char *name; 2868 size_t namelen; 2869 char *buffer; 2870 size_t buflen; 2871 }; 2872 2873 static void * 2874 try_library_path(const char *dir, size_t dirlen, void *param) 2875 { 2876 struct try_library_args *arg; 2877 2878 arg = param; 2879 if (*dir == '/' || trust) { 2880 char *pathname; 2881 2882 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2883 return (NULL); 2884 2885 pathname = arg->buffer; 2886 strncpy(pathname, dir, dirlen); 2887 pathname[dirlen] = '/'; 2888 strcpy(pathname + dirlen + 1, arg->name); 2889 2890 dbg(" Trying \"%s\"", pathname); 2891 if (access(pathname, F_OK) == 0) { /* We found it */ 2892 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2893 strcpy(pathname, arg->buffer); 2894 return (pathname); 2895 } 2896 } 2897 return (NULL); 2898 } 2899 2900 static char * 2901 search_library_path(const char *name, const char *path) 2902 { 2903 char *p; 2904 struct try_library_args arg; 2905 2906 if (path == NULL) 2907 return NULL; 2908 2909 arg.name = name; 2910 arg.namelen = strlen(name); 2911 arg.buffer = xmalloc(PATH_MAX); 2912 arg.buflen = PATH_MAX; 2913 2914 p = path_enumerate(path, try_library_path, &arg); 2915 2916 free(arg.buffer); 2917 2918 return (p); 2919 } 2920 2921 2922 /* 2923 * Finds the library with the given name using the directory descriptors 2924 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2925 * 2926 * Returns a freshly-opened close-on-exec file descriptor for the library, 2927 * or -1 if the library cannot be found. 2928 */ 2929 static char * 2930 search_library_pathfds(const char *name, const char *path, int *fdp) 2931 { 2932 char *envcopy, *fdstr, *found, *last_token; 2933 size_t len; 2934 int dirfd, fd; 2935 2936 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2937 2938 /* Don't load from user-specified libdirs into setuid binaries. */ 2939 if (!trust) 2940 return (NULL); 2941 2942 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2943 if (path == NULL) 2944 return (NULL); 2945 2946 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2947 if (name[0] == '/') { 2948 dbg("Absolute path (%s) passed to %s", name, __func__); 2949 return (NULL); 2950 } 2951 2952 /* 2953 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2954 * copy of the path, as strtok_r rewrites separator tokens 2955 * with '\0'. 2956 */ 2957 found = NULL; 2958 envcopy = xstrdup(path); 2959 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2960 fdstr = strtok_r(NULL, ":", &last_token)) { 2961 dirfd = parse_libdir(fdstr); 2962 if (dirfd < 0) 2963 break; 2964 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2965 if (fd >= 0) { 2966 *fdp = fd; 2967 len = strlen(fdstr) + strlen(name) + 3; 2968 found = xmalloc(len); 2969 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2970 _rtld_error("error generating '%d/%s'", 2971 dirfd, name); 2972 rtld_die(); 2973 } 2974 dbg("open('%s') => %d", found, fd); 2975 break; 2976 } 2977 } 2978 free(envcopy); 2979 2980 return (found); 2981 } 2982 2983 2984 int 2985 dlclose(void *handle) 2986 { 2987 Obj_Entry *root; 2988 RtldLockState lockstate; 2989 2990 wlock_acquire(rtld_bind_lock, &lockstate); 2991 root = dlcheck(handle); 2992 if (root == NULL) { 2993 lock_release(rtld_bind_lock, &lockstate); 2994 return -1; 2995 } 2996 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2997 root->path); 2998 2999 /* Unreference the object and its dependencies. */ 3000 root->dl_refcount--; 3001 3002 if (root->refcount == 1) { 3003 /* 3004 * The object will be no longer referenced, so we must unload it. 3005 * First, call the fini functions. 3006 */ 3007 objlist_call_fini(&list_fini, root, &lockstate); 3008 3009 unref_dag(root); 3010 3011 /* Finish cleaning up the newly-unreferenced objects. */ 3012 GDB_STATE(RT_DELETE,&root->linkmap); 3013 unload_object(root); 3014 GDB_STATE(RT_CONSISTENT,NULL); 3015 } else 3016 unref_dag(root); 3017 3018 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3019 lock_release(rtld_bind_lock, &lockstate); 3020 return 0; 3021 } 3022 3023 char * 3024 dlerror(void) 3025 { 3026 char *msg = error_message; 3027 error_message = NULL; 3028 return msg; 3029 } 3030 3031 /* 3032 * This function is deprecated and has no effect. 3033 */ 3034 void 3035 dllockinit(void *context, 3036 void *(*lock_create)(void *context), 3037 void (*rlock_acquire)(void *lock), 3038 void (*wlock_acquire)(void *lock), 3039 void (*lock_release)(void *lock), 3040 void (*lock_destroy)(void *lock), 3041 void (*context_destroy)(void *context)) 3042 { 3043 static void *cur_context; 3044 static void (*cur_context_destroy)(void *); 3045 3046 /* Just destroy the context from the previous call, if necessary. */ 3047 if (cur_context_destroy != NULL) 3048 cur_context_destroy(cur_context); 3049 cur_context = context; 3050 cur_context_destroy = context_destroy; 3051 } 3052 3053 void * 3054 dlopen(const char *name, int mode) 3055 { 3056 3057 return (rtld_dlopen(name, -1, mode)); 3058 } 3059 3060 void * 3061 fdlopen(int fd, int mode) 3062 { 3063 3064 return (rtld_dlopen(NULL, fd, mode)); 3065 } 3066 3067 static void * 3068 rtld_dlopen(const char *name, int fd, int mode) 3069 { 3070 RtldLockState lockstate; 3071 int lo_flags; 3072 3073 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3074 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3075 if (ld_tracing != NULL) { 3076 rlock_acquire(rtld_bind_lock, &lockstate); 3077 if (sigsetjmp(lockstate.env, 0) != 0) 3078 lock_upgrade(rtld_bind_lock, &lockstate); 3079 environ = (char **)*get_program_var_addr("environ", &lockstate); 3080 lock_release(rtld_bind_lock, &lockstate); 3081 } 3082 lo_flags = RTLD_LO_DLOPEN; 3083 if (mode & RTLD_NODELETE) 3084 lo_flags |= RTLD_LO_NODELETE; 3085 if (mode & RTLD_NOLOAD) 3086 lo_flags |= RTLD_LO_NOLOAD; 3087 if (ld_tracing != NULL) 3088 lo_flags |= RTLD_LO_TRACE; 3089 3090 return (dlopen_object(name, fd, obj_main, lo_flags, 3091 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3092 } 3093 3094 static void 3095 dlopen_cleanup(Obj_Entry *obj) 3096 { 3097 3098 obj->dl_refcount--; 3099 unref_dag(obj); 3100 if (obj->refcount == 0) 3101 unload_object(obj); 3102 } 3103 3104 static Obj_Entry * 3105 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3106 int mode, RtldLockState *lockstate) 3107 { 3108 Obj_Entry *old_obj_tail; 3109 Obj_Entry *obj; 3110 Objlist initlist; 3111 RtldLockState mlockstate; 3112 int result; 3113 3114 objlist_init(&initlist); 3115 3116 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3117 wlock_acquire(rtld_bind_lock, &mlockstate); 3118 lockstate = &mlockstate; 3119 } 3120 GDB_STATE(RT_ADD,NULL); 3121 3122 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3123 obj = NULL; 3124 if (name == NULL && fd == -1) { 3125 obj = obj_main; 3126 obj->refcount++; 3127 } else { 3128 obj = load_object(name, fd, refobj, lo_flags); 3129 } 3130 3131 if (obj) { 3132 obj->dl_refcount++; 3133 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3134 objlist_push_tail(&list_global, obj); 3135 if (globallist_next(old_obj_tail) != NULL) { 3136 /* We loaded something new. */ 3137 assert(globallist_next(old_obj_tail) == obj); 3138 result = load_needed_objects(obj, 3139 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3140 init_dag(obj); 3141 ref_dag(obj); 3142 if (result != -1) 3143 result = rtld_verify_versions(&obj->dagmembers); 3144 if (result != -1 && ld_tracing) 3145 goto trace; 3146 if (result == -1 || relocate_object_dag(obj, 3147 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3148 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3149 lockstate) == -1) { 3150 dlopen_cleanup(obj); 3151 obj = NULL; 3152 } else if (lo_flags & RTLD_LO_EARLY) { 3153 /* 3154 * Do not call the init functions for early loaded 3155 * filtees. The image is still not initialized enough 3156 * for them to work. 3157 * 3158 * Our object is found by the global object list and 3159 * will be ordered among all init calls done right 3160 * before transferring control to main. 3161 */ 3162 } else { 3163 /* Make list of init functions to call. */ 3164 initlist_add_objects(obj, obj, &initlist); 3165 } 3166 /* 3167 * Process all no_delete or global objects here, given 3168 * them own DAGs to prevent their dependencies from being 3169 * unloaded. This has to be done after we have loaded all 3170 * of the dependencies, so that we do not miss any. 3171 */ 3172 if (obj != NULL) 3173 process_z(obj); 3174 } else { 3175 /* 3176 * Bump the reference counts for objects on this DAG. If 3177 * this is the first dlopen() call for the object that was 3178 * already loaded as a dependency, initialize the dag 3179 * starting at it. 3180 */ 3181 init_dag(obj); 3182 ref_dag(obj); 3183 3184 if ((lo_flags & RTLD_LO_TRACE) != 0) 3185 goto trace; 3186 } 3187 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3188 obj->z_nodelete) && !obj->ref_nodel) { 3189 dbg("obj %s nodelete", obj->path); 3190 ref_dag(obj); 3191 obj->z_nodelete = obj->ref_nodel = true; 3192 } 3193 } 3194 3195 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3196 name); 3197 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3198 3199 if (!(lo_flags & RTLD_LO_EARLY)) { 3200 map_stacks_exec(lockstate); 3201 } 3202 3203 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3204 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3205 lockstate) == -1) { 3206 objlist_clear(&initlist); 3207 dlopen_cleanup(obj); 3208 if (lockstate == &mlockstate) 3209 lock_release(rtld_bind_lock, lockstate); 3210 return (NULL); 3211 } 3212 3213 if (!(lo_flags & RTLD_LO_EARLY)) { 3214 /* Call the init functions. */ 3215 objlist_call_init(&initlist, lockstate); 3216 } 3217 objlist_clear(&initlist); 3218 if (lockstate == &mlockstate) 3219 lock_release(rtld_bind_lock, lockstate); 3220 return obj; 3221 trace: 3222 trace_loaded_objects(obj); 3223 if (lockstate == &mlockstate) 3224 lock_release(rtld_bind_lock, lockstate); 3225 exit(0); 3226 } 3227 3228 static void * 3229 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3230 int flags) 3231 { 3232 DoneList donelist; 3233 const Obj_Entry *obj, *defobj; 3234 const Elf_Sym *def; 3235 SymLook req; 3236 RtldLockState lockstate; 3237 tls_index ti; 3238 void *sym; 3239 int res; 3240 3241 def = NULL; 3242 defobj = NULL; 3243 symlook_init(&req, name); 3244 req.ventry = ve; 3245 req.flags = flags | SYMLOOK_IN_PLT; 3246 req.lockstate = &lockstate; 3247 3248 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3249 rlock_acquire(rtld_bind_lock, &lockstate); 3250 if (sigsetjmp(lockstate.env, 0) != 0) 3251 lock_upgrade(rtld_bind_lock, &lockstate); 3252 if (handle == NULL || handle == RTLD_NEXT || 3253 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3254 3255 if ((obj = obj_from_addr(retaddr)) == NULL) { 3256 _rtld_error("Cannot determine caller's shared object"); 3257 lock_release(rtld_bind_lock, &lockstate); 3258 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3259 return NULL; 3260 } 3261 if (handle == NULL) { /* Just the caller's shared object. */ 3262 res = symlook_obj(&req, obj); 3263 if (res == 0) { 3264 def = req.sym_out; 3265 defobj = req.defobj_out; 3266 } 3267 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3268 handle == RTLD_SELF) { /* ... caller included */ 3269 if (handle == RTLD_NEXT) 3270 obj = globallist_next(obj); 3271 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3272 if (obj->marker) 3273 continue; 3274 res = symlook_obj(&req, obj); 3275 if (res == 0) { 3276 if (def == NULL || 3277 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3278 def = req.sym_out; 3279 defobj = req.defobj_out; 3280 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3281 break; 3282 } 3283 } 3284 } 3285 /* 3286 * Search the dynamic linker itself, and possibly resolve the 3287 * symbol from there. This is how the application links to 3288 * dynamic linker services such as dlopen. 3289 */ 3290 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3291 res = symlook_obj(&req, &obj_rtld); 3292 if (res == 0) { 3293 def = req.sym_out; 3294 defobj = req.defobj_out; 3295 } 3296 } 3297 } else { 3298 assert(handle == RTLD_DEFAULT); 3299 res = symlook_default(&req, obj); 3300 if (res == 0) { 3301 defobj = req.defobj_out; 3302 def = req.sym_out; 3303 } 3304 } 3305 } else { 3306 if ((obj = dlcheck(handle)) == NULL) { 3307 lock_release(rtld_bind_lock, &lockstate); 3308 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3309 return NULL; 3310 } 3311 3312 donelist_init(&donelist); 3313 if (obj->mainprog) { 3314 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3315 res = symlook_global(&req, &donelist); 3316 if (res == 0) { 3317 def = req.sym_out; 3318 defobj = req.defobj_out; 3319 } 3320 /* 3321 * Search the dynamic linker itself, and possibly resolve the 3322 * symbol from there. This is how the application links to 3323 * dynamic linker services such as dlopen. 3324 */ 3325 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3326 res = symlook_obj(&req, &obj_rtld); 3327 if (res == 0) { 3328 def = req.sym_out; 3329 defobj = req.defobj_out; 3330 } 3331 } 3332 } 3333 else { 3334 /* Search the whole DAG rooted at the given object. */ 3335 res = symlook_list(&req, &obj->dagmembers, &donelist); 3336 if (res == 0) { 3337 def = req.sym_out; 3338 defobj = req.defobj_out; 3339 } 3340 } 3341 } 3342 3343 if (def != NULL) { 3344 lock_release(rtld_bind_lock, &lockstate); 3345 3346 /* 3347 * The value required by the caller is derived from the value 3348 * of the symbol. this is simply the relocated value of the 3349 * symbol. 3350 */ 3351 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3352 sym = make_function_pointer(def, defobj); 3353 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3354 sym = rtld_resolve_ifunc(defobj, def); 3355 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3356 ti.ti_module = defobj->tlsindex; 3357 ti.ti_offset = def->st_value; 3358 sym = __tls_get_addr(&ti); 3359 } else 3360 sym = defobj->relocbase + def->st_value; 3361 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3362 return (sym); 3363 } 3364 3365 _rtld_error("Undefined symbol \"%s\"", name); 3366 lock_release(rtld_bind_lock, &lockstate); 3367 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3368 return NULL; 3369 } 3370 3371 void * 3372 dlsym(void *handle, const char *name) 3373 { 3374 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3375 SYMLOOK_DLSYM); 3376 } 3377 3378 dlfunc_t 3379 dlfunc(void *handle, const char *name) 3380 { 3381 union { 3382 void *d; 3383 dlfunc_t f; 3384 } rv; 3385 3386 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3387 SYMLOOK_DLSYM); 3388 return (rv.f); 3389 } 3390 3391 void * 3392 dlvsym(void *handle, const char *name, const char *version) 3393 { 3394 Ver_Entry ventry; 3395 3396 ventry.name = version; 3397 ventry.file = NULL; 3398 ventry.hash = elf_hash(version); 3399 ventry.flags= 0; 3400 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3401 SYMLOOK_DLSYM); 3402 } 3403 3404 int 3405 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3406 { 3407 const Obj_Entry *obj; 3408 RtldLockState lockstate; 3409 3410 rlock_acquire(rtld_bind_lock, &lockstate); 3411 obj = obj_from_addr(addr); 3412 if (obj == NULL) { 3413 _rtld_error("No shared object contains address"); 3414 lock_release(rtld_bind_lock, &lockstate); 3415 return (0); 3416 } 3417 rtld_fill_dl_phdr_info(obj, phdr_info); 3418 lock_release(rtld_bind_lock, &lockstate); 3419 return (1); 3420 } 3421 3422 int 3423 dladdr(const void *addr, Dl_info *info) 3424 { 3425 const Obj_Entry *obj; 3426 const Elf_Sym *def; 3427 void *symbol_addr; 3428 unsigned long symoffset; 3429 RtldLockState lockstate; 3430 3431 rlock_acquire(rtld_bind_lock, &lockstate); 3432 obj = obj_from_addr(addr); 3433 if (obj == NULL) { 3434 _rtld_error("No shared object contains address"); 3435 lock_release(rtld_bind_lock, &lockstate); 3436 return 0; 3437 } 3438 info->dli_fname = obj->path; 3439 info->dli_fbase = obj->mapbase; 3440 info->dli_saddr = (void *)0; 3441 info->dli_sname = NULL; 3442 3443 /* 3444 * Walk the symbol list looking for the symbol whose address is 3445 * closest to the address sent in. 3446 */ 3447 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3448 def = obj->symtab + symoffset; 3449 3450 /* 3451 * For skip the symbol if st_shndx is either SHN_UNDEF or 3452 * SHN_COMMON. 3453 */ 3454 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3455 continue; 3456 3457 /* 3458 * If the symbol is greater than the specified address, or if it 3459 * is further away from addr than the current nearest symbol, 3460 * then reject it. 3461 */ 3462 symbol_addr = obj->relocbase + def->st_value; 3463 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3464 continue; 3465 3466 /* Update our idea of the nearest symbol. */ 3467 info->dli_sname = obj->strtab + def->st_name; 3468 info->dli_saddr = symbol_addr; 3469 3470 /* Exact match? */ 3471 if (info->dli_saddr == addr) 3472 break; 3473 } 3474 lock_release(rtld_bind_lock, &lockstate); 3475 return 1; 3476 } 3477 3478 int 3479 dlinfo(void *handle, int request, void *p) 3480 { 3481 const Obj_Entry *obj; 3482 RtldLockState lockstate; 3483 int error; 3484 3485 rlock_acquire(rtld_bind_lock, &lockstate); 3486 3487 if (handle == NULL || handle == RTLD_SELF) { 3488 void *retaddr; 3489 3490 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3491 if ((obj = obj_from_addr(retaddr)) == NULL) 3492 _rtld_error("Cannot determine caller's shared object"); 3493 } else 3494 obj = dlcheck(handle); 3495 3496 if (obj == NULL) { 3497 lock_release(rtld_bind_lock, &lockstate); 3498 return (-1); 3499 } 3500 3501 error = 0; 3502 switch (request) { 3503 case RTLD_DI_LINKMAP: 3504 *((struct link_map const **)p) = &obj->linkmap; 3505 break; 3506 case RTLD_DI_ORIGIN: 3507 error = rtld_dirname(obj->path, p); 3508 break; 3509 3510 case RTLD_DI_SERINFOSIZE: 3511 case RTLD_DI_SERINFO: 3512 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3513 break; 3514 3515 default: 3516 _rtld_error("Invalid request %d passed to dlinfo()", request); 3517 error = -1; 3518 } 3519 3520 lock_release(rtld_bind_lock, &lockstate); 3521 3522 return (error); 3523 } 3524 3525 static void 3526 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3527 { 3528 3529 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3530 phdr_info->dlpi_name = obj->path; 3531 phdr_info->dlpi_phdr = obj->phdr; 3532 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3533 phdr_info->dlpi_tls_modid = obj->tlsindex; 3534 phdr_info->dlpi_tls_data = obj->tlsinit; 3535 phdr_info->dlpi_adds = obj_loads; 3536 phdr_info->dlpi_subs = obj_loads - obj_count; 3537 } 3538 3539 int 3540 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3541 { 3542 struct dl_phdr_info phdr_info; 3543 Obj_Entry *obj, marker; 3544 RtldLockState bind_lockstate, phdr_lockstate; 3545 int error; 3546 3547 bzero(&marker, sizeof(marker)); 3548 marker.marker = true; 3549 error = 0; 3550 3551 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3552 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3553 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3554 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3555 rtld_fill_dl_phdr_info(obj, &phdr_info); 3556 lock_release(rtld_bind_lock, &bind_lockstate); 3557 3558 error = callback(&phdr_info, sizeof phdr_info, param); 3559 3560 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3561 obj = globallist_next(&marker); 3562 TAILQ_REMOVE(&obj_list, &marker, next); 3563 if (error != 0) { 3564 lock_release(rtld_bind_lock, &bind_lockstate); 3565 lock_release(rtld_phdr_lock, &phdr_lockstate); 3566 return (error); 3567 } 3568 } 3569 3570 if (error == 0) { 3571 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3572 lock_release(rtld_bind_lock, &bind_lockstate); 3573 error = callback(&phdr_info, sizeof(phdr_info), param); 3574 } 3575 lock_release(rtld_phdr_lock, &phdr_lockstate); 3576 return (error); 3577 } 3578 3579 static void * 3580 fill_search_info(const char *dir, size_t dirlen, void *param) 3581 { 3582 struct fill_search_info_args *arg; 3583 3584 arg = param; 3585 3586 if (arg->request == RTLD_DI_SERINFOSIZE) { 3587 arg->serinfo->dls_cnt ++; 3588 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3589 } else { 3590 struct dl_serpath *s_entry; 3591 3592 s_entry = arg->serpath; 3593 s_entry->dls_name = arg->strspace; 3594 s_entry->dls_flags = arg->flags; 3595 3596 strncpy(arg->strspace, dir, dirlen); 3597 arg->strspace[dirlen] = '\0'; 3598 3599 arg->strspace += dirlen + 1; 3600 arg->serpath++; 3601 } 3602 3603 return (NULL); 3604 } 3605 3606 static int 3607 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3608 { 3609 struct dl_serinfo _info; 3610 struct fill_search_info_args args; 3611 3612 args.request = RTLD_DI_SERINFOSIZE; 3613 args.serinfo = &_info; 3614 3615 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3616 _info.dls_cnt = 0; 3617 3618 path_enumerate(obj->rpath, fill_search_info, &args); 3619 path_enumerate(ld_library_path, fill_search_info, &args); 3620 path_enumerate(obj->runpath, fill_search_info, &args); 3621 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3622 if (!obj->z_nodeflib) 3623 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3624 3625 3626 if (request == RTLD_DI_SERINFOSIZE) { 3627 info->dls_size = _info.dls_size; 3628 info->dls_cnt = _info.dls_cnt; 3629 return (0); 3630 } 3631 3632 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3633 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3634 return (-1); 3635 } 3636 3637 args.request = RTLD_DI_SERINFO; 3638 args.serinfo = info; 3639 args.serpath = &info->dls_serpath[0]; 3640 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3641 3642 args.flags = LA_SER_RUNPATH; 3643 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3644 return (-1); 3645 3646 args.flags = LA_SER_LIBPATH; 3647 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3648 return (-1); 3649 3650 args.flags = LA_SER_RUNPATH; 3651 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3652 return (-1); 3653 3654 args.flags = LA_SER_CONFIG; 3655 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3656 != NULL) 3657 return (-1); 3658 3659 args.flags = LA_SER_DEFAULT; 3660 if (!obj->z_nodeflib && 3661 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3662 return (-1); 3663 return (0); 3664 } 3665 3666 static int 3667 rtld_dirname(const char *path, char *bname) 3668 { 3669 const char *endp; 3670 3671 /* Empty or NULL string gets treated as "." */ 3672 if (path == NULL || *path == '\0') { 3673 bname[0] = '.'; 3674 bname[1] = '\0'; 3675 return (0); 3676 } 3677 3678 /* Strip trailing slashes */ 3679 endp = path + strlen(path) - 1; 3680 while (endp > path && *endp == '/') 3681 endp--; 3682 3683 /* Find the start of the dir */ 3684 while (endp > path && *endp != '/') 3685 endp--; 3686 3687 /* Either the dir is "/" or there are no slashes */ 3688 if (endp == path) { 3689 bname[0] = *endp == '/' ? '/' : '.'; 3690 bname[1] = '\0'; 3691 return (0); 3692 } else { 3693 do { 3694 endp--; 3695 } while (endp > path && *endp == '/'); 3696 } 3697 3698 if (endp - path + 2 > PATH_MAX) 3699 { 3700 _rtld_error("Filename is too long: %s", path); 3701 return(-1); 3702 } 3703 3704 strncpy(bname, path, endp - path + 1); 3705 bname[endp - path + 1] = '\0'; 3706 return (0); 3707 } 3708 3709 static int 3710 rtld_dirname_abs(const char *path, char *base) 3711 { 3712 char *last; 3713 3714 if (realpath(path, base) == NULL) 3715 return (-1); 3716 dbg("%s -> %s", path, base); 3717 last = strrchr(base, '/'); 3718 if (last == NULL) 3719 return (-1); 3720 if (last != base) 3721 *last = '\0'; 3722 return (0); 3723 } 3724 3725 static void 3726 linkmap_add(Obj_Entry *obj) 3727 { 3728 struct link_map *l = &obj->linkmap; 3729 struct link_map *prev; 3730 3731 obj->linkmap.l_name = obj->path; 3732 obj->linkmap.l_addr = obj->mapbase; 3733 obj->linkmap.l_ld = obj->dynamic; 3734 #ifdef __mips__ 3735 /* GDB needs load offset on MIPS to use the symbols */ 3736 obj->linkmap.l_offs = obj->relocbase; 3737 #endif 3738 3739 if (r_debug.r_map == NULL) { 3740 r_debug.r_map = l; 3741 return; 3742 } 3743 3744 /* 3745 * Scan to the end of the list, but not past the entry for the 3746 * dynamic linker, which we want to keep at the very end. 3747 */ 3748 for (prev = r_debug.r_map; 3749 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3750 prev = prev->l_next) 3751 ; 3752 3753 /* Link in the new entry. */ 3754 l->l_prev = prev; 3755 l->l_next = prev->l_next; 3756 if (l->l_next != NULL) 3757 l->l_next->l_prev = l; 3758 prev->l_next = l; 3759 } 3760 3761 static void 3762 linkmap_delete(Obj_Entry *obj) 3763 { 3764 struct link_map *l = &obj->linkmap; 3765 3766 if (l->l_prev == NULL) { 3767 if ((r_debug.r_map = l->l_next) != NULL) 3768 l->l_next->l_prev = NULL; 3769 return; 3770 } 3771 3772 if ((l->l_prev->l_next = l->l_next) != NULL) 3773 l->l_next->l_prev = l->l_prev; 3774 } 3775 3776 /* 3777 * Function for the debugger to set a breakpoint on to gain control. 3778 * 3779 * The two parameters allow the debugger to easily find and determine 3780 * what the runtime loader is doing and to whom it is doing it. 3781 * 3782 * When the loadhook trap is hit (r_debug_state, set at program 3783 * initialization), the arguments can be found on the stack: 3784 * 3785 * +8 struct link_map *m 3786 * +4 struct r_debug *rd 3787 * +0 RetAddr 3788 */ 3789 void 3790 r_debug_state(struct r_debug* rd, struct link_map *m) 3791 { 3792 /* 3793 * The following is a hack to force the compiler to emit calls to 3794 * this function, even when optimizing. If the function is empty, 3795 * the compiler is not obliged to emit any code for calls to it, 3796 * even when marked __noinline. However, gdb depends on those 3797 * calls being made. 3798 */ 3799 __compiler_membar(); 3800 } 3801 3802 /* 3803 * A function called after init routines have completed. This can be used to 3804 * break before a program's entry routine is called, and can be used when 3805 * main is not available in the symbol table. 3806 */ 3807 void 3808 _r_debug_postinit(struct link_map *m) 3809 { 3810 3811 /* See r_debug_state(). */ 3812 __compiler_membar(); 3813 } 3814 3815 /* 3816 * Get address of the pointer variable in the main program. 3817 * Prefer non-weak symbol over the weak one. 3818 */ 3819 static const void ** 3820 get_program_var_addr(const char *name, RtldLockState *lockstate) 3821 { 3822 SymLook req; 3823 DoneList donelist; 3824 3825 symlook_init(&req, name); 3826 req.lockstate = lockstate; 3827 donelist_init(&donelist); 3828 if (symlook_global(&req, &donelist) != 0) 3829 return (NULL); 3830 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3831 return ((const void **)make_function_pointer(req.sym_out, 3832 req.defobj_out)); 3833 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3834 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3835 else 3836 return ((const void **)(req.defobj_out->relocbase + 3837 req.sym_out->st_value)); 3838 } 3839 3840 /* 3841 * Set a pointer variable in the main program to the given value. This 3842 * is used to set key variables such as "environ" before any of the 3843 * init functions are called. 3844 */ 3845 static void 3846 set_program_var(const char *name, const void *value) 3847 { 3848 const void **addr; 3849 3850 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3851 dbg("\"%s\": *%p <-- %p", name, addr, value); 3852 *addr = value; 3853 } 3854 } 3855 3856 /* 3857 * Search the global objects, including dependencies and main object, 3858 * for the given symbol. 3859 */ 3860 static int 3861 symlook_global(SymLook *req, DoneList *donelist) 3862 { 3863 SymLook req1; 3864 const Objlist_Entry *elm; 3865 int res; 3866 3867 symlook_init_from_req(&req1, req); 3868 3869 /* Search all objects loaded at program start up. */ 3870 if (req->defobj_out == NULL || 3871 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3872 res = symlook_list(&req1, &list_main, donelist); 3873 if (res == 0 && (req->defobj_out == NULL || 3874 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3875 req->sym_out = req1.sym_out; 3876 req->defobj_out = req1.defobj_out; 3877 assert(req->defobj_out != NULL); 3878 } 3879 } 3880 3881 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3882 STAILQ_FOREACH(elm, &list_global, link) { 3883 if (req->defobj_out != NULL && 3884 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3885 break; 3886 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3887 if (res == 0 && (req->defobj_out == NULL || 3888 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3889 req->sym_out = req1.sym_out; 3890 req->defobj_out = req1.defobj_out; 3891 assert(req->defobj_out != NULL); 3892 } 3893 } 3894 3895 return (req->sym_out != NULL ? 0 : ESRCH); 3896 } 3897 3898 /* 3899 * Given a symbol name in a referencing object, find the corresponding 3900 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3901 * no definition was found. Returns a pointer to the Obj_Entry of the 3902 * defining object via the reference parameter DEFOBJ_OUT. 3903 */ 3904 static int 3905 symlook_default(SymLook *req, const Obj_Entry *refobj) 3906 { 3907 DoneList donelist; 3908 const Objlist_Entry *elm; 3909 SymLook req1; 3910 int res; 3911 3912 donelist_init(&donelist); 3913 symlook_init_from_req(&req1, req); 3914 3915 /* Look first in the referencing object if linked symbolically. */ 3916 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3917 res = symlook_obj(&req1, refobj); 3918 if (res == 0) { 3919 req->sym_out = req1.sym_out; 3920 req->defobj_out = req1.defobj_out; 3921 assert(req->defobj_out != NULL); 3922 } 3923 } 3924 3925 symlook_global(req, &donelist); 3926 3927 /* Search all dlopened DAGs containing the referencing object. */ 3928 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3929 if (req->sym_out != NULL && 3930 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3931 break; 3932 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3933 if (res == 0 && (req->sym_out == NULL || 3934 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3935 req->sym_out = req1.sym_out; 3936 req->defobj_out = req1.defobj_out; 3937 assert(req->defobj_out != NULL); 3938 } 3939 } 3940 3941 /* 3942 * Search the dynamic linker itself, and possibly resolve the 3943 * symbol from there. This is how the application links to 3944 * dynamic linker services such as dlopen. 3945 */ 3946 if (req->sym_out == NULL || 3947 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3948 res = symlook_obj(&req1, &obj_rtld); 3949 if (res == 0) { 3950 req->sym_out = req1.sym_out; 3951 req->defobj_out = req1.defobj_out; 3952 assert(req->defobj_out != NULL); 3953 } 3954 } 3955 3956 return (req->sym_out != NULL ? 0 : ESRCH); 3957 } 3958 3959 static int 3960 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3961 { 3962 const Elf_Sym *def; 3963 const Obj_Entry *defobj; 3964 const Objlist_Entry *elm; 3965 SymLook req1; 3966 int res; 3967 3968 def = NULL; 3969 defobj = NULL; 3970 STAILQ_FOREACH(elm, objlist, link) { 3971 if (donelist_check(dlp, elm->obj)) 3972 continue; 3973 symlook_init_from_req(&req1, req); 3974 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3975 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3976 def = req1.sym_out; 3977 defobj = req1.defobj_out; 3978 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3979 break; 3980 } 3981 } 3982 } 3983 if (def != NULL) { 3984 req->sym_out = def; 3985 req->defobj_out = defobj; 3986 return (0); 3987 } 3988 return (ESRCH); 3989 } 3990 3991 /* 3992 * Search the chain of DAGS cointed to by the given Needed_Entry 3993 * for a symbol of the given name. Each DAG is scanned completely 3994 * before advancing to the next one. Returns a pointer to the symbol, 3995 * or NULL if no definition was found. 3996 */ 3997 static int 3998 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3999 { 4000 const Elf_Sym *def; 4001 const Needed_Entry *n; 4002 const Obj_Entry *defobj; 4003 SymLook req1; 4004 int res; 4005 4006 def = NULL; 4007 defobj = NULL; 4008 symlook_init_from_req(&req1, req); 4009 for (n = needed; n != NULL; n = n->next) { 4010 if (n->obj == NULL || 4011 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4012 continue; 4013 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4014 def = req1.sym_out; 4015 defobj = req1.defobj_out; 4016 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4017 break; 4018 } 4019 } 4020 if (def != NULL) { 4021 req->sym_out = def; 4022 req->defobj_out = defobj; 4023 return (0); 4024 } 4025 return (ESRCH); 4026 } 4027 4028 /* 4029 * Search the symbol table of a single shared object for a symbol of 4030 * the given name and version, if requested. Returns a pointer to the 4031 * symbol, or NULL if no definition was found. If the object is 4032 * filter, return filtered symbol from filtee. 4033 * 4034 * The symbol's hash value is passed in for efficiency reasons; that 4035 * eliminates many recomputations of the hash value. 4036 */ 4037 int 4038 symlook_obj(SymLook *req, const Obj_Entry *obj) 4039 { 4040 DoneList donelist; 4041 SymLook req1; 4042 int flags, res, mres; 4043 4044 /* 4045 * If there is at least one valid hash at this point, we prefer to 4046 * use the faster GNU version if available. 4047 */ 4048 if (obj->valid_hash_gnu) 4049 mres = symlook_obj1_gnu(req, obj); 4050 else if (obj->valid_hash_sysv) 4051 mres = symlook_obj1_sysv(req, obj); 4052 else 4053 return (EINVAL); 4054 4055 if (mres == 0) { 4056 if (obj->needed_filtees != NULL) { 4057 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4058 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4059 donelist_init(&donelist); 4060 symlook_init_from_req(&req1, req); 4061 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4062 if (res == 0) { 4063 req->sym_out = req1.sym_out; 4064 req->defobj_out = req1.defobj_out; 4065 } 4066 return (res); 4067 } 4068 if (obj->needed_aux_filtees != NULL) { 4069 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4070 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4071 donelist_init(&donelist); 4072 symlook_init_from_req(&req1, req); 4073 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4074 if (res == 0) { 4075 req->sym_out = req1.sym_out; 4076 req->defobj_out = req1.defobj_out; 4077 return (res); 4078 } 4079 } 4080 } 4081 return (mres); 4082 } 4083 4084 /* Symbol match routine common to both hash functions */ 4085 static bool 4086 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4087 const unsigned long symnum) 4088 { 4089 Elf_Versym verndx; 4090 const Elf_Sym *symp; 4091 const char *strp; 4092 4093 symp = obj->symtab + symnum; 4094 strp = obj->strtab + symp->st_name; 4095 4096 switch (ELF_ST_TYPE(symp->st_info)) { 4097 case STT_FUNC: 4098 case STT_NOTYPE: 4099 case STT_OBJECT: 4100 case STT_COMMON: 4101 case STT_GNU_IFUNC: 4102 if (symp->st_value == 0) 4103 return (false); 4104 /* fallthrough */ 4105 case STT_TLS: 4106 if (symp->st_shndx != SHN_UNDEF) 4107 break; 4108 #ifndef __mips__ 4109 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4110 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4111 break; 4112 /* fallthrough */ 4113 #endif 4114 default: 4115 return (false); 4116 } 4117 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4118 return (false); 4119 4120 if (req->ventry == NULL) { 4121 if (obj->versyms != NULL) { 4122 verndx = VER_NDX(obj->versyms[symnum]); 4123 if (verndx > obj->vernum) { 4124 _rtld_error( 4125 "%s: symbol %s references wrong version %d", 4126 obj->path, obj->strtab + symnum, verndx); 4127 return (false); 4128 } 4129 /* 4130 * If we are not called from dlsym (i.e. this 4131 * is a normal relocation from unversioned 4132 * binary), accept the symbol immediately if 4133 * it happens to have first version after this 4134 * shared object became versioned. Otherwise, 4135 * if symbol is versioned and not hidden, 4136 * remember it. If it is the only symbol with 4137 * this name exported by the shared object, it 4138 * will be returned as a match by the calling 4139 * function. If symbol is global (verndx < 2) 4140 * accept it unconditionally. 4141 */ 4142 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4143 verndx == VER_NDX_GIVEN) { 4144 result->sym_out = symp; 4145 return (true); 4146 } 4147 else if (verndx >= VER_NDX_GIVEN) { 4148 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4149 == 0) { 4150 if (result->vsymp == NULL) 4151 result->vsymp = symp; 4152 result->vcount++; 4153 } 4154 return (false); 4155 } 4156 } 4157 result->sym_out = symp; 4158 return (true); 4159 } 4160 if (obj->versyms == NULL) { 4161 if (object_match_name(obj, req->ventry->name)) { 4162 _rtld_error("%s: object %s should provide version %s " 4163 "for symbol %s", obj_rtld.path, obj->path, 4164 req->ventry->name, obj->strtab + symnum); 4165 return (false); 4166 } 4167 } else { 4168 verndx = VER_NDX(obj->versyms[symnum]); 4169 if (verndx > obj->vernum) { 4170 _rtld_error("%s: symbol %s references wrong version %d", 4171 obj->path, obj->strtab + symnum, verndx); 4172 return (false); 4173 } 4174 if (obj->vertab[verndx].hash != req->ventry->hash || 4175 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4176 /* 4177 * Version does not match. Look if this is a 4178 * global symbol and if it is not hidden. If 4179 * global symbol (verndx < 2) is available, 4180 * use it. Do not return symbol if we are 4181 * called by dlvsym, because dlvsym looks for 4182 * a specific version and default one is not 4183 * what dlvsym wants. 4184 */ 4185 if ((req->flags & SYMLOOK_DLSYM) || 4186 (verndx >= VER_NDX_GIVEN) || 4187 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4188 return (false); 4189 } 4190 } 4191 result->sym_out = symp; 4192 return (true); 4193 } 4194 4195 /* 4196 * Search for symbol using SysV hash function. 4197 * obj->buckets is known not to be NULL at this point; the test for this was 4198 * performed with the obj->valid_hash_sysv assignment. 4199 */ 4200 static int 4201 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4202 { 4203 unsigned long symnum; 4204 Sym_Match_Result matchres; 4205 4206 matchres.sym_out = NULL; 4207 matchres.vsymp = NULL; 4208 matchres.vcount = 0; 4209 4210 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4211 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4212 if (symnum >= obj->nchains) 4213 return (ESRCH); /* Bad object */ 4214 4215 if (matched_symbol(req, obj, &matchres, symnum)) { 4216 req->sym_out = matchres.sym_out; 4217 req->defobj_out = obj; 4218 return (0); 4219 } 4220 } 4221 if (matchres.vcount == 1) { 4222 req->sym_out = matchres.vsymp; 4223 req->defobj_out = obj; 4224 return (0); 4225 } 4226 return (ESRCH); 4227 } 4228 4229 /* Search for symbol using GNU hash function */ 4230 static int 4231 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4232 { 4233 Elf_Addr bloom_word; 4234 const Elf32_Word *hashval; 4235 Elf32_Word bucket; 4236 Sym_Match_Result matchres; 4237 unsigned int h1, h2; 4238 unsigned long symnum; 4239 4240 matchres.sym_out = NULL; 4241 matchres.vsymp = NULL; 4242 matchres.vcount = 0; 4243 4244 /* Pick right bitmask word from Bloom filter array */ 4245 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4246 obj->maskwords_bm_gnu]; 4247 4248 /* Calculate modulus word size of gnu hash and its derivative */ 4249 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4250 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4251 4252 /* Filter out the "definitely not in set" queries */ 4253 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4254 return (ESRCH); 4255 4256 /* Locate hash chain and corresponding value element*/ 4257 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4258 if (bucket == 0) 4259 return (ESRCH); 4260 hashval = &obj->chain_zero_gnu[bucket]; 4261 do { 4262 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4263 symnum = hashval - obj->chain_zero_gnu; 4264 if (matched_symbol(req, obj, &matchres, symnum)) { 4265 req->sym_out = matchres.sym_out; 4266 req->defobj_out = obj; 4267 return (0); 4268 } 4269 } 4270 } while ((*hashval++ & 1) == 0); 4271 if (matchres.vcount == 1) { 4272 req->sym_out = matchres.vsymp; 4273 req->defobj_out = obj; 4274 return (0); 4275 } 4276 return (ESRCH); 4277 } 4278 4279 static void 4280 trace_loaded_objects(Obj_Entry *obj) 4281 { 4282 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4283 int c; 4284 4285 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4286 main_local = ""; 4287 4288 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4289 fmt1 = "\t%o => %p (%x)\n"; 4290 4291 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4292 fmt2 = "\t%o (%x)\n"; 4293 4294 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4295 4296 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4297 Needed_Entry *needed; 4298 char *name, *path; 4299 bool is_lib; 4300 4301 if (obj->marker) 4302 continue; 4303 if (list_containers && obj->needed != NULL) 4304 rtld_printf("%s:\n", obj->path); 4305 for (needed = obj->needed; needed; needed = needed->next) { 4306 if (needed->obj != NULL) { 4307 if (needed->obj->traced && !list_containers) 4308 continue; 4309 needed->obj->traced = true; 4310 path = needed->obj->path; 4311 } else 4312 path = "not found"; 4313 4314 name = (char *)obj->strtab + needed->name; 4315 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4316 4317 fmt = is_lib ? fmt1 : fmt2; 4318 while ((c = *fmt++) != '\0') { 4319 switch (c) { 4320 default: 4321 rtld_putchar(c); 4322 continue; 4323 case '\\': 4324 switch (c = *fmt) { 4325 case '\0': 4326 continue; 4327 case 'n': 4328 rtld_putchar('\n'); 4329 break; 4330 case 't': 4331 rtld_putchar('\t'); 4332 break; 4333 } 4334 break; 4335 case '%': 4336 switch (c = *fmt) { 4337 case '\0': 4338 continue; 4339 case '%': 4340 default: 4341 rtld_putchar(c); 4342 break; 4343 case 'A': 4344 rtld_putstr(main_local); 4345 break; 4346 case 'a': 4347 rtld_putstr(obj_main->path); 4348 break; 4349 case 'o': 4350 rtld_putstr(name); 4351 break; 4352 #if 0 4353 case 'm': 4354 rtld_printf("%d", sodp->sod_major); 4355 break; 4356 case 'n': 4357 rtld_printf("%d", sodp->sod_minor); 4358 break; 4359 #endif 4360 case 'p': 4361 rtld_putstr(path); 4362 break; 4363 case 'x': 4364 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4365 0); 4366 break; 4367 } 4368 break; 4369 } 4370 ++fmt; 4371 } 4372 } 4373 } 4374 } 4375 4376 /* 4377 * Unload a dlopened object and its dependencies from memory and from 4378 * our data structures. It is assumed that the DAG rooted in the 4379 * object has already been unreferenced, and that the object has a 4380 * reference count of 0. 4381 */ 4382 static void 4383 unload_object(Obj_Entry *root) 4384 { 4385 Obj_Entry *obj, *obj1; 4386 4387 assert(root->refcount == 0); 4388 4389 /* 4390 * Pass over the DAG removing unreferenced objects from 4391 * appropriate lists. 4392 */ 4393 unlink_object(root); 4394 4395 /* Unmap all objects that are no longer referenced. */ 4396 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4397 if (obj->marker || obj->refcount != 0) 4398 continue; 4399 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4400 obj->mapsize, 0, obj->path); 4401 dbg("unloading \"%s\"", obj->path); 4402 unload_filtees(root); 4403 munmap(obj->mapbase, obj->mapsize); 4404 linkmap_delete(obj); 4405 TAILQ_REMOVE(&obj_list, obj, next); 4406 obj_count--; 4407 obj_free(obj); 4408 } 4409 } 4410 4411 static void 4412 unlink_object(Obj_Entry *root) 4413 { 4414 Objlist_Entry *elm; 4415 4416 if (root->refcount == 0) { 4417 /* Remove the object from the RTLD_GLOBAL list. */ 4418 objlist_remove(&list_global, root); 4419 4420 /* Remove the object from all objects' DAG lists. */ 4421 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4422 objlist_remove(&elm->obj->dldags, root); 4423 if (elm->obj != root) 4424 unlink_object(elm->obj); 4425 } 4426 } 4427 } 4428 4429 static void 4430 ref_dag(Obj_Entry *root) 4431 { 4432 Objlist_Entry *elm; 4433 4434 assert(root->dag_inited); 4435 STAILQ_FOREACH(elm, &root->dagmembers, link) 4436 elm->obj->refcount++; 4437 } 4438 4439 static void 4440 unref_dag(Obj_Entry *root) 4441 { 4442 Objlist_Entry *elm; 4443 4444 assert(root->dag_inited); 4445 STAILQ_FOREACH(elm, &root->dagmembers, link) 4446 elm->obj->refcount--; 4447 } 4448 4449 /* 4450 * Common code for MD __tls_get_addr(). 4451 */ 4452 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4453 static void * 4454 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4455 { 4456 Elf_Addr *newdtv, *dtv; 4457 RtldLockState lockstate; 4458 int to_copy; 4459 4460 dtv = *dtvp; 4461 /* Check dtv generation in case new modules have arrived */ 4462 if (dtv[0] != tls_dtv_generation) { 4463 wlock_acquire(rtld_bind_lock, &lockstate); 4464 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4465 to_copy = dtv[1]; 4466 if (to_copy > tls_max_index) 4467 to_copy = tls_max_index; 4468 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4469 newdtv[0] = tls_dtv_generation; 4470 newdtv[1] = tls_max_index; 4471 free(dtv); 4472 lock_release(rtld_bind_lock, &lockstate); 4473 dtv = *dtvp = newdtv; 4474 } 4475 4476 /* Dynamically allocate module TLS if necessary */ 4477 if (dtv[index + 1] == 0) { 4478 /* Signal safe, wlock will block out signals. */ 4479 wlock_acquire(rtld_bind_lock, &lockstate); 4480 if (!dtv[index + 1]) 4481 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4482 lock_release(rtld_bind_lock, &lockstate); 4483 } 4484 return ((void *)(dtv[index + 1] + offset)); 4485 } 4486 4487 void * 4488 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4489 { 4490 Elf_Addr *dtv; 4491 4492 dtv = *dtvp; 4493 /* Check dtv generation in case new modules have arrived */ 4494 if (__predict_true(dtv[0] == tls_dtv_generation && 4495 dtv[index + 1] != 0)) 4496 return ((void *)(dtv[index + 1] + offset)); 4497 return (tls_get_addr_slow(dtvp, index, offset)); 4498 } 4499 4500 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4501 defined(__powerpc__) || defined(__riscv__) 4502 4503 /* 4504 * Allocate Static TLS using the Variant I method. 4505 */ 4506 void * 4507 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4508 { 4509 Obj_Entry *obj; 4510 char *tcb; 4511 Elf_Addr **tls; 4512 Elf_Addr *dtv; 4513 Elf_Addr addr; 4514 int i; 4515 4516 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4517 return (oldtcb); 4518 4519 assert(tcbsize >= TLS_TCB_SIZE); 4520 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4521 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4522 4523 if (oldtcb != NULL) { 4524 memcpy(tls, oldtcb, tls_static_space); 4525 free(oldtcb); 4526 4527 /* Adjust the DTV. */ 4528 dtv = tls[0]; 4529 for (i = 0; i < dtv[1]; i++) { 4530 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4531 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4532 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4533 } 4534 } 4535 } else { 4536 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4537 tls[0] = dtv; 4538 dtv[0] = tls_dtv_generation; 4539 dtv[1] = tls_max_index; 4540 4541 for (obj = globallist_curr(objs); obj != NULL; 4542 obj = globallist_next(obj)) { 4543 if (obj->tlsoffset > 0) { 4544 addr = (Elf_Addr)tls + obj->tlsoffset; 4545 if (obj->tlsinitsize > 0) 4546 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4547 if (obj->tlssize > obj->tlsinitsize) 4548 memset((void*) (addr + obj->tlsinitsize), 0, 4549 obj->tlssize - obj->tlsinitsize); 4550 dtv[obj->tlsindex + 1] = addr; 4551 } 4552 } 4553 } 4554 4555 return (tcb); 4556 } 4557 4558 void 4559 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4560 { 4561 Elf_Addr *dtv; 4562 Elf_Addr tlsstart, tlsend; 4563 int dtvsize, i; 4564 4565 assert(tcbsize >= TLS_TCB_SIZE); 4566 4567 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4568 tlsend = tlsstart + tls_static_space; 4569 4570 dtv = *(Elf_Addr **)tlsstart; 4571 dtvsize = dtv[1]; 4572 for (i = 0; i < dtvsize; i++) { 4573 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4574 free((void*)dtv[i+2]); 4575 } 4576 } 4577 free(dtv); 4578 free(tcb); 4579 } 4580 4581 #endif 4582 4583 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4584 4585 /* 4586 * Allocate Static TLS using the Variant II method. 4587 */ 4588 void * 4589 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4590 { 4591 Obj_Entry *obj; 4592 size_t size, ralign; 4593 char *tls; 4594 Elf_Addr *dtv, *olddtv; 4595 Elf_Addr segbase, oldsegbase, addr; 4596 int i; 4597 4598 ralign = tcbalign; 4599 if (tls_static_max_align > ralign) 4600 ralign = tls_static_max_align; 4601 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4602 4603 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4604 tls = malloc_aligned(size, ralign); 4605 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4606 4607 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4608 ((Elf_Addr*)segbase)[0] = segbase; 4609 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4610 4611 dtv[0] = tls_dtv_generation; 4612 dtv[1] = tls_max_index; 4613 4614 if (oldtls) { 4615 /* 4616 * Copy the static TLS block over whole. 4617 */ 4618 oldsegbase = (Elf_Addr) oldtls; 4619 memcpy((void *)(segbase - tls_static_space), 4620 (const void *)(oldsegbase - tls_static_space), 4621 tls_static_space); 4622 4623 /* 4624 * If any dynamic TLS blocks have been created tls_get_addr(), 4625 * move them over. 4626 */ 4627 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4628 for (i = 0; i < olddtv[1]; i++) { 4629 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4630 dtv[i+2] = olddtv[i+2]; 4631 olddtv[i+2] = 0; 4632 } 4633 } 4634 4635 /* 4636 * We assume that this block was the one we created with 4637 * allocate_initial_tls(). 4638 */ 4639 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4640 } else { 4641 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4642 if (obj->marker || obj->tlsoffset == 0) 4643 continue; 4644 addr = segbase - obj->tlsoffset; 4645 memset((void*) (addr + obj->tlsinitsize), 4646 0, obj->tlssize - obj->tlsinitsize); 4647 if (obj->tlsinit) 4648 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4649 dtv[obj->tlsindex + 1] = addr; 4650 } 4651 } 4652 4653 return (void*) segbase; 4654 } 4655 4656 void 4657 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4658 { 4659 Elf_Addr* dtv; 4660 size_t size, ralign; 4661 int dtvsize, i; 4662 Elf_Addr tlsstart, tlsend; 4663 4664 /* 4665 * Figure out the size of the initial TLS block so that we can 4666 * find stuff which ___tls_get_addr() allocated dynamically. 4667 */ 4668 ralign = tcbalign; 4669 if (tls_static_max_align > ralign) 4670 ralign = tls_static_max_align; 4671 size = round(tls_static_space, ralign); 4672 4673 dtv = ((Elf_Addr**)tls)[1]; 4674 dtvsize = dtv[1]; 4675 tlsend = (Elf_Addr) tls; 4676 tlsstart = tlsend - size; 4677 for (i = 0; i < dtvsize; i++) { 4678 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4679 free_aligned((void *)dtv[i + 2]); 4680 } 4681 } 4682 4683 free_aligned((void *)tlsstart); 4684 free((void*) dtv); 4685 } 4686 4687 #endif 4688 4689 /* 4690 * Allocate TLS block for module with given index. 4691 */ 4692 void * 4693 allocate_module_tls(int index) 4694 { 4695 Obj_Entry* obj; 4696 char* p; 4697 4698 TAILQ_FOREACH(obj, &obj_list, next) { 4699 if (obj->marker) 4700 continue; 4701 if (obj->tlsindex == index) 4702 break; 4703 } 4704 if (!obj) { 4705 _rtld_error("Can't find module with TLS index %d", index); 4706 rtld_die(); 4707 } 4708 4709 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4710 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4711 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4712 4713 return p; 4714 } 4715 4716 bool 4717 allocate_tls_offset(Obj_Entry *obj) 4718 { 4719 size_t off; 4720 4721 if (obj->tls_done) 4722 return true; 4723 4724 if (obj->tlssize == 0) { 4725 obj->tls_done = true; 4726 return true; 4727 } 4728 4729 if (tls_last_offset == 0) 4730 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4731 else 4732 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4733 obj->tlssize, obj->tlsalign); 4734 4735 /* 4736 * If we have already fixed the size of the static TLS block, we 4737 * must stay within that size. When allocating the static TLS, we 4738 * leave a small amount of space spare to be used for dynamically 4739 * loading modules which use static TLS. 4740 */ 4741 if (tls_static_space != 0) { 4742 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4743 return false; 4744 } else if (obj->tlsalign > tls_static_max_align) { 4745 tls_static_max_align = obj->tlsalign; 4746 } 4747 4748 tls_last_offset = obj->tlsoffset = off; 4749 tls_last_size = obj->tlssize; 4750 obj->tls_done = true; 4751 4752 return true; 4753 } 4754 4755 void 4756 free_tls_offset(Obj_Entry *obj) 4757 { 4758 4759 /* 4760 * If we were the last thing to allocate out of the static TLS 4761 * block, we give our space back to the 'allocator'. This is a 4762 * simplistic workaround to allow libGL.so.1 to be loaded and 4763 * unloaded multiple times. 4764 */ 4765 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4766 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4767 tls_last_offset -= obj->tlssize; 4768 tls_last_size = 0; 4769 } 4770 } 4771 4772 void * 4773 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4774 { 4775 void *ret; 4776 RtldLockState lockstate; 4777 4778 wlock_acquire(rtld_bind_lock, &lockstate); 4779 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4780 tcbsize, tcbalign); 4781 lock_release(rtld_bind_lock, &lockstate); 4782 return (ret); 4783 } 4784 4785 void 4786 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4787 { 4788 RtldLockState lockstate; 4789 4790 wlock_acquire(rtld_bind_lock, &lockstate); 4791 free_tls(tcb, tcbsize, tcbalign); 4792 lock_release(rtld_bind_lock, &lockstate); 4793 } 4794 4795 static void 4796 object_add_name(Obj_Entry *obj, const char *name) 4797 { 4798 Name_Entry *entry; 4799 size_t len; 4800 4801 len = strlen(name); 4802 entry = malloc(sizeof(Name_Entry) + len); 4803 4804 if (entry != NULL) { 4805 strcpy(entry->name, name); 4806 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4807 } 4808 } 4809 4810 static int 4811 object_match_name(const Obj_Entry *obj, const char *name) 4812 { 4813 Name_Entry *entry; 4814 4815 STAILQ_FOREACH(entry, &obj->names, link) { 4816 if (strcmp(name, entry->name) == 0) 4817 return (1); 4818 } 4819 return (0); 4820 } 4821 4822 static Obj_Entry * 4823 locate_dependency(const Obj_Entry *obj, const char *name) 4824 { 4825 const Objlist_Entry *entry; 4826 const Needed_Entry *needed; 4827 4828 STAILQ_FOREACH(entry, &list_main, link) { 4829 if (object_match_name(entry->obj, name)) 4830 return entry->obj; 4831 } 4832 4833 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4834 if (strcmp(obj->strtab + needed->name, name) == 0 || 4835 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4836 /* 4837 * If there is DT_NEEDED for the name we are looking for, 4838 * we are all set. Note that object might not be found if 4839 * dependency was not loaded yet, so the function can 4840 * return NULL here. This is expected and handled 4841 * properly by the caller. 4842 */ 4843 return (needed->obj); 4844 } 4845 } 4846 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4847 obj->path, name); 4848 rtld_die(); 4849 } 4850 4851 static int 4852 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4853 const Elf_Vernaux *vna) 4854 { 4855 const Elf_Verdef *vd; 4856 const char *vername; 4857 4858 vername = refobj->strtab + vna->vna_name; 4859 vd = depobj->verdef; 4860 if (vd == NULL) { 4861 _rtld_error("%s: version %s required by %s not defined", 4862 depobj->path, vername, refobj->path); 4863 return (-1); 4864 } 4865 for (;;) { 4866 if (vd->vd_version != VER_DEF_CURRENT) { 4867 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4868 depobj->path, vd->vd_version); 4869 return (-1); 4870 } 4871 if (vna->vna_hash == vd->vd_hash) { 4872 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4873 ((char *)vd + vd->vd_aux); 4874 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4875 return (0); 4876 } 4877 if (vd->vd_next == 0) 4878 break; 4879 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4880 } 4881 if (vna->vna_flags & VER_FLG_WEAK) 4882 return (0); 4883 _rtld_error("%s: version %s required by %s not found", 4884 depobj->path, vername, refobj->path); 4885 return (-1); 4886 } 4887 4888 static int 4889 rtld_verify_object_versions(Obj_Entry *obj) 4890 { 4891 const Elf_Verneed *vn; 4892 const Elf_Verdef *vd; 4893 const Elf_Verdaux *vda; 4894 const Elf_Vernaux *vna; 4895 const Obj_Entry *depobj; 4896 int maxvernum, vernum; 4897 4898 if (obj->ver_checked) 4899 return (0); 4900 obj->ver_checked = true; 4901 4902 maxvernum = 0; 4903 /* 4904 * Walk over defined and required version records and figure out 4905 * max index used by any of them. Do very basic sanity checking 4906 * while there. 4907 */ 4908 vn = obj->verneed; 4909 while (vn != NULL) { 4910 if (vn->vn_version != VER_NEED_CURRENT) { 4911 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4912 obj->path, vn->vn_version); 4913 return (-1); 4914 } 4915 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4916 for (;;) { 4917 vernum = VER_NEED_IDX(vna->vna_other); 4918 if (vernum > maxvernum) 4919 maxvernum = vernum; 4920 if (vna->vna_next == 0) 4921 break; 4922 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4923 } 4924 if (vn->vn_next == 0) 4925 break; 4926 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4927 } 4928 4929 vd = obj->verdef; 4930 while (vd != NULL) { 4931 if (vd->vd_version != VER_DEF_CURRENT) { 4932 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4933 obj->path, vd->vd_version); 4934 return (-1); 4935 } 4936 vernum = VER_DEF_IDX(vd->vd_ndx); 4937 if (vernum > maxvernum) 4938 maxvernum = vernum; 4939 if (vd->vd_next == 0) 4940 break; 4941 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4942 } 4943 4944 if (maxvernum == 0) 4945 return (0); 4946 4947 /* 4948 * Store version information in array indexable by version index. 4949 * Verify that object version requirements are satisfied along the 4950 * way. 4951 */ 4952 obj->vernum = maxvernum + 1; 4953 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4954 4955 vd = obj->verdef; 4956 while (vd != NULL) { 4957 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4958 vernum = VER_DEF_IDX(vd->vd_ndx); 4959 assert(vernum <= maxvernum); 4960 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4961 obj->vertab[vernum].hash = vd->vd_hash; 4962 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4963 obj->vertab[vernum].file = NULL; 4964 obj->vertab[vernum].flags = 0; 4965 } 4966 if (vd->vd_next == 0) 4967 break; 4968 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4969 } 4970 4971 vn = obj->verneed; 4972 while (vn != NULL) { 4973 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4974 if (depobj == NULL) 4975 return (-1); 4976 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4977 for (;;) { 4978 if (check_object_provided_version(obj, depobj, vna)) 4979 return (-1); 4980 vernum = VER_NEED_IDX(vna->vna_other); 4981 assert(vernum <= maxvernum); 4982 obj->vertab[vernum].hash = vna->vna_hash; 4983 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4984 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4985 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4986 VER_INFO_HIDDEN : 0; 4987 if (vna->vna_next == 0) 4988 break; 4989 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4990 } 4991 if (vn->vn_next == 0) 4992 break; 4993 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4994 } 4995 return 0; 4996 } 4997 4998 static int 4999 rtld_verify_versions(const Objlist *objlist) 5000 { 5001 Objlist_Entry *entry; 5002 int rc; 5003 5004 rc = 0; 5005 STAILQ_FOREACH(entry, objlist, link) { 5006 /* 5007 * Skip dummy objects or objects that have their version requirements 5008 * already checked. 5009 */ 5010 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5011 continue; 5012 if (rtld_verify_object_versions(entry->obj) == -1) { 5013 rc = -1; 5014 if (ld_tracing == NULL) 5015 break; 5016 } 5017 } 5018 if (rc == 0 || ld_tracing != NULL) 5019 rc = rtld_verify_object_versions(&obj_rtld); 5020 return rc; 5021 } 5022 5023 const Ver_Entry * 5024 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5025 { 5026 Elf_Versym vernum; 5027 5028 if (obj->vertab) { 5029 vernum = VER_NDX(obj->versyms[symnum]); 5030 if (vernum >= obj->vernum) { 5031 _rtld_error("%s: symbol %s has wrong verneed value %d", 5032 obj->path, obj->strtab + symnum, vernum); 5033 } else if (obj->vertab[vernum].hash != 0) { 5034 return &obj->vertab[vernum]; 5035 } 5036 } 5037 return NULL; 5038 } 5039 5040 int 5041 _rtld_get_stack_prot(void) 5042 { 5043 5044 return (stack_prot); 5045 } 5046 5047 int 5048 _rtld_is_dlopened(void *arg) 5049 { 5050 Obj_Entry *obj; 5051 RtldLockState lockstate; 5052 int res; 5053 5054 rlock_acquire(rtld_bind_lock, &lockstate); 5055 obj = dlcheck(arg); 5056 if (obj == NULL) 5057 obj = obj_from_addr(arg); 5058 if (obj == NULL) { 5059 _rtld_error("No shared object contains address"); 5060 lock_release(rtld_bind_lock, &lockstate); 5061 return (-1); 5062 } 5063 res = obj->dlopened ? 1 : 0; 5064 lock_release(rtld_bind_lock, &lockstate); 5065 return (res); 5066 } 5067 5068 static void 5069 map_stacks_exec(RtldLockState *lockstate) 5070 { 5071 void (*thr_map_stacks_exec)(void); 5072 5073 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5074 return; 5075 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5076 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5077 if (thr_map_stacks_exec != NULL) { 5078 stack_prot |= PROT_EXEC; 5079 thr_map_stacks_exec(); 5080 } 5081 } 5082 5083 void 5084 symlook_init(SymLook *dst, const char *name) 5085 { 5086 5087 bzero(dst, sizeof(*dst)); 5088 dst->name = name; 5089 dst->hash = elf_hash(name); 5090 dst->hash_gnu = gnu_hash(name); 5091 } 5092 5093 static void 5094 symlook_init_from_req(SymLook *dst, const SymLook *src) 5095 { 5096 5097 dst->name = src->name; 5098 dst->hash = src->hash; 5099 dst->hash_gnu = src->hash_gnu; 5100 dst->ventry = src->ventry; 5101 dst->flags = src->flags; 5102 dst->defobj_out = NULL; 5103 dst->sym_out = NULL; 5104 dst->lockstate = src->lockstate; 5105 } 5106 5107 5108 /* 5109 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5110 */ 5111 static int 5112 parse_libdir(const char *str) 5113 { 5114 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5115 const char *orig; 5116 int fd; 5117 char c; 5118 5119 orig = str; 5120 fd = 0; 5121 for (c = *str; c != '\0'; c = *++str) { 5122 if (c < '0' || c > '9') 5123 return (-1); 5124 5125 fd *= RADIX; 5126 fd += c - '0'; 5127 } 5128 5129 /* Make sure we actually parsed something. */ 5130 if (str == orig) { 5131 _rtld_error("failed to parse directory FD from '%s'", str); 5132 return (-1); 5133 } 5134 return (fd); 5135 } 5136 5137 /* 5138 * Overrides for libc_pic-provided functions. 5139 */ 5140 5141 int 5142 __getosreldate(void) 5143 { 5144 size_t len; 5145 int oid[2]; 5146 int error, osrel; 5147 5148 if (osreldate != 0) 5149 return (osreldate); 5150 5151 oid[0] = CTL_KERN; 5152 oid[1] = KERN_OSRELDATE; 5153 osrel = 0; 5154 len = sizeof(osrel); 5155 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5156 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5157 osreldate = osrel; 5158 return (osreldate); 5159 } 5160 5161 void 5162 exit(int status) 5163 { 5164 5165 _exit(status); 5166 } 5167 5168 void (*__cleanup)(void); 5169 int __isthreaded = 0; 5170 int _thread_autoinit_dummy_decl = 1; 5171 5172 /* 5173 * No unresolved symbols for rtld. 5174 */ 5175 void 5176 __pthread_cxa_finalize(struct dl_phdr_info *a) 5177 { 5178 } 5179 5180 void 5181 __stack_chk_fail(void) 5182 { 5183 5184 _rtld_error("stack overflow detected; terminated"); 5185 rtld_die(); 5186 } 5187 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5188 5189 void 5190 __chk_fail(void) 5191 { 5192 5193 _rtld_error("buffer overflow detected; terminated"); 5194 rtld_die(); 5195 } 5196 5197 const char * 5198 rtld_strerror(int errnum) 5199 { 5200 5201 if (errnum < 0 || errnum >= sys_nerr) 5202 return ("Unknown error"); 5203 return (sys_errlist[errnum]); 5204 } 5205