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 #ifndef RTLD_IS_DYNAMIC 204 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 205 #endif 206 207 int dlclose(void *) __exported; 208 char *dlerror(void) __exported; 209 void *dlopen(const char *, int) __exported; 210 void *fdlopen(int, int) __exported; 211 void *dlsym(void *, const char *) __exported; 212 dlfunc_t dlfunc(void *, const char *) __exported; 213 void *dlvsym(void *, const char *, const char *) __exported; 214 int dladdr(const void *, Dl_info *) __exported; 215 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 216 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 217 int dlinfo(void *, int , void *) __exported; 218 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 219 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 220 int _rtld_get_stack_prot(void) __exported; 221 int _rtld_is_dlopened(void *) __exported; 222 void _rtld_error(const char *, ...) __exported; 223 224 int npagesizes, osreldate; 225 size_t *pagesizes; 226 227 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 228 229 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 230 static int max_stack_flags; 231 232 /* 233 * Global declarations normally provided by crt1. The dynamic linker is 234 * not built with crt1, so we have to provide them ourselves. 235 */ 236 char *__progname; 237 char **environ; 238 239 /* 240 * Used to pass argc, argv to init functions. 241 */ 242 int main_argc; 243 char **main_argv; 244 245 /* 246 * Globals to control TLS allocation. 247 */ 248 size_t tls_last_offset; /* Static TLS offset of last module */ 249 size_t tls_last_size; /* Static TLS size of last module */ 250 size_t tls_static_space; /* Static TLS space allocated */ 251 size_t tls_static_max_align; 252 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 253 int tls_max_index = 1; /* Largest module index allocated */ 254 255 bool ld_library_path_rpath = false; 256 257 /* 258 * Globals for path names, and such 259 */ 260 char *ld_elf_hints_default = _PATH_ELF_HINTS; 261 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 262 char *ld_path_rtld = _PATH_RTLD; 263 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 264 char *ld_env_prefix = LD_; 265 266 /* 267 * Fill in a DoneList with an allocation large enough to hold all of 268 * the currently-loaded objects. Keep this as a macro since it calls 269 * alloca and we want that to occur within the scope of the caller. 270 */ 271 #define donelist_init(dlp) \ 272 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 273 assert((dlp)->objs != NULL), \ 274 (dlp)->num_alloc = obj_count, \ 275 (dlp)->num_used = 0) 276 277 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 278 if (ld_utrace != NULL) \ 279 ld_utrace_log(e, h, mb, ms, r, n); \ 280 } while (0) 281 282 static void 283 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 284 int refcnt, const char *name) 285 { 286 struct utrace_rtld ut; 287 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 288 289 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 290 ut.event = event; 291 ut.handle = handle; 292 ut.mapbase = mapbase; 293 ut.mapsize = mapsize; 294 ut.refcnt = refcnt; 295 bzero(ut.name, sizeof(ut.name)); 296 if (name) 297 strlcpy(ut.name, name, sizeof(ut.name)); 298 utrace(&ut, sizeof(ut)); 299 } 300 301 #ifdef RTLD_VARIANT_ENV_NAMES 302 /* 303 * construct the env variable based on the type of binary that's 304 * running. 305 */ 306 static inline const char * 307 _LD(const char *var) 308 { 309 static char buffer[128]; 310 311 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 312 strlcat(buffer, var, sizeof(buffer)); 313 return (buffer); 314 } 315 #else 316 #define _LD(x) LD_ x 317 #endif 318 319 /* 320 * Main entry point for dynamic linking. The first argument is the 321 * stack pointer. The stack is expected to be laid out as described 322 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 323 * Specifically, the stack pointer points to a word containing 324 * ARGC. Following that in the stack is a null-terminated sequence 325 * of pointers to argument strings. Then comes a null-terminated 326 * sequence of pointers to environment strings. Finally, there is a 327 * sequence of "auxiliary vector" entries. 328 * 329 * The second argument points to a place to store the dynamic linker's 330 * exit procedure pointer and the third to a place to store the main 331 * program's object. 332 * 333 * The return value is the main program's entry point. 334 */ 335 func_ptr_type 336 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 337 { 338 Elf_Auxinfo *aux_info[AT_COUNT]; 339 int i; 340 int argc; 341 char **argv; 342 char **env; 343 Elf_Auxinfo *aux; 344 Elf_Auxinfo *auxp; 345 const char *argv0; 346 Objlist_Entry *entry; 347 Obj_Entry *obj; 348 Obj_Entry *preload_tail; 349 Obj_Entry *last_interposer; 350 Objlist initlist; 351 RtldLockState lockstate; 352 char *library_path_rpath; 353 int mib[2]; 354 size_t len; 355 356 /* 357 * On entry, the dynamic linker itself has not been relocated yet. 358 * Be very careful not to reference any global data until after 359 * init_rtld has returned. It is OK to reference file-scope statics 360 * and string constants, and to call static and global functions. 361 */ 362 363 /* Find the auxiliary vector on the stack. */ 364 argc = *sp++; 365 argv = (char **) sp; 366 sp += argc + 1; /* Skip over arguments and NULL terminator */ 367 env = (char **) sp; 368 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 369 ; 370 aux = (Elf_Auxinfo *) sp; 371 372 /* Digest the auxiliary vector. */ 373 for (i = 0; i < AT_COUNT; i++) 374 aux_info[i] = NULL; 375 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 376 if (auxp->a_type < AT_COUNT) 377 aux_info[auxp->a_type] = auxp; 378 } 379 380 /* Initialize and relocate ourselves. */ 381 assert(aux_info[AT_BASE] != NULL); 382 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 383 384 __progname = obj_rtld.path; 385 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 386 environ = env; 387 main_argc = argc; 388 main_argv = argv; 389 390 if (aux_info[AT_CANARY] != NULL && 391 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 392 i = aux_info[AT_CANARYLEN]->a_un.a_val; 393 if (i > sizeof(__stack_chk_guard)) 394 i = sizeof(__stack_chk_guard); 395 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 396 } else { 397 mib[0] = CTL_KERN; 398 mib[1] = KERN_ARND; 399 400 len = sizeof(__stack_chk_guard); 401 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 402 len != sizeof(__stack_chk_guard)) { 403 /* If sysctl was unsuccessful, use the "terminator canary". */ 404 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 405 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 406 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 407 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 408 } 409 } 410 411 trust = !issetugid(); 412 413 md_abi_variant_hook(aux_info); 414 415 ld_bind_now = getenv(_LD("BIND_NOW")); 416 /* 417 * If the process is tainted, then we un-set the dangerous environment 418 * variables. The process will be marked as tainted until setuid(2) 419 * is called. If any child process calls setuid(2) we do not want any 420 * future processes to honor the potentially un-safe variables. 421 */ 422 if (!trust) { 423 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 424 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 425 unsetenv(_LD("LIBMAP_DISABLE")) || 426 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 427 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 428 _rtld_error("environment corrupt; aborting"); 429 rtld_die(); 430 } 431 } 432 ld_debug = getenv(_LD("DEBUG")); 433 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 434 libmap_override = getenv(_LD("LIBMAP")); 435 ld_library_path = getenv(_LD("LIBRARY_PATH")); 436 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 437 ld_preload = getenv(_LD("PRELOAD")); 438 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 439 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 440 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 441 if (library_path_rpath != NULL) { 442 if (library_path_rpath[0] == 'y' || 443 library_path_rpath[0] == 'Y' || 444 library_path_rpath[0] == '1') 445 ld_library_path_rpath = true; 446 else 447 ld_library_path_rpath = false; 448 } 449 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 450 (ld_library_path != NULL) || (ld_preload != NULL) || 451 (ld_elf_hints_path != NULL) || ld_loadfltr; 452 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 453 ld_utrace = getenv(_LD("UTRACE")); 454 455 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 456 ld_elf_hints_path = ld_elf_hints_default; 457 458 if (ld_debug != NULL && *ld_debug != '\0') 459 debug = 1; 460 dbg("%s is initialized, base address = %p", __progname, 461 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 462 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 463 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 464 465 dbg("initializing thread locks"); 466 lockdflt_init(); 467 468 /* 469 * Load the main program, or process its program header if it is 470 * already loaded. 471 */ 472 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 473 int fd = aux_info[AT_EXECFD]->a_un.a_val; 474 dbg("loading main program"); 475 obj_main = map_object(fd, argv0, NULL); 476 close(fd); 477 if (obj_main == NULL) 478 rtld_die(); 479 max_stack_flags = obj->stack_flags; 480 } else { /* Main program already loaded. */ 481 const Elf_Phdr *phdr; 482 int phnum; 483 caddr_t entry; 484 485 dbg("processing main program's program header"); 486 assert(aux_info[AT_PHDR] != NULL); 487 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 488 assert(aux_info[AT_PHNUM] != NULL); 489 phnum = aux_info[AT_PHNUM]->a_un.a_val; 490 assert(aux_info[AT_PHENT] != NULL); 491 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 492 assert(aux_info[AT_ENTRY] != NULL); 493 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 494 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 495 rtld_die(); 496 } 497 498 if (aux_info[AT_EXECPATH] != NULL) { 499 char *kexecpath; 500 char buf[MAXPATHLEN]; 501 502 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 503 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 504 if (kexecpath[0] == '/') 505 obj_main->path = kexecpath; 506 else if (getcwd(buf, sizeof(buf)) == NULL || 507 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 508 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 509 obj_main->path = xstrdup(argv0); 510 else 511 obj_main->path = xstrdup(buf); 512 } else { 513 dbg("No AT_EXECPATH"); 514 obj_main->path = xstrdup(argv0); 515 } 516 dbg("obj_main path %s", obj_main->path); 517 obj_main->mainprog = true; 518 519 if (aux_info[AT_STACKPROT] != NULL && 520 aux_info[AT_STACKPROT]->a_un.a_val != 0) 521 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 522 523 #ifndef COMPAT_32BIT 524 /* 525 * Get the actual dynamic linker pathname from the executable if 526 * possible. (It should always be possible.) That ensures that 527 * gdb will find the right dynamic linker even if a non-standard 528 * one is being used. 529 */ 530 if (obj_main->interp != NULL && 531 strcmp(obj_main->interp, obj_rtld.path) != 0) { 532 free(obj_rtld.path); 533 obj_rtld.path = xstrdup(obj_main->interp); 534 __progname = obj_rtld.path; 535 } 536 #endif 537 538 digest_dynamic(obj_main, 0); 539 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 540 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 541 obj_main->dynsymcount); 542 543 linkmap_add(obj_main); 544 linkmap_add(&obj_rtld); 545 546 /* Link the main program into the list of objects. */ 547 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 548 obj_count++; 549 obj_loads++; 550 551 /* Initialize a fake symbol for resolving undefined weak references. */ 552 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 553 sym_zero.st_shndx = SHN_UNDEF; 554 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 555 556 if (!libmap_disable) 557 libmap_disable = (bool)lm_init(libmap_override); 558 559 dbg("loading LD_PRELOAD libraries"); 560 if (load_preload_objects() == -1) 561 rtld_die(); 562 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 563 564 dbg("loading needed objects"); 565 if (load_needed_objects(obj_main, 0) == -1) 566 rtld_die(); 567 568 /* Make a list of all objects loaded at startup. */ 569 last_interposer = obj_main; 570 TAILQ_FOREACH(obj, &obj_list, next) { 571 if (obj->marker) 572 continue; 573 if (obj->z_interpose && obj != obj_main) { 574 objlist_put_after(&list_main, last_interposer, obj); 575 last_interposer = obj; 576 } else { 577 objlist_push_tail(&list_main, obj); 578 } 579 obj->refcount++; 580 } 581 582 dbg("checking for required versions"); 583 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 584 rtld_die(); 585 586 if (ld_tracing) { /* We're done */ 587 trace_loaded_objects(obj_main); 588 exit(0); 589 } 590 591 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 592 dump_relocations(obj_main); 593 exit (0); 594 } 595 596 /* 597 * Processing tls relocations requires having the tls offsets 598 * initialized. Prepare offsets before starting initial 599 * relocation processing. 600 */ 601 dbg("initializing initial thread local storage offsets"); 602 STAILQ_FOREACH(entry, &list_main, link) { 603 /* 604 * Allocate all the initial objects out of the static TLS 605 * block even if they didn't ask for it. 606 */ 607 allocate_tls_offset(entry->obj); 608 } 609 610 if (relocate_objects(obj_main, 611 ld_bind_now != NULL && *ld_bind_now != '\0', 612 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 613 rtld_die(); 614 615 dbg("doing copy relocations"); 616 if (do_copy_relocations(obj_main) == -1) 617 rtld_die(); 618 619 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 620 dump_relocations(obj_main); 621 exit (0); 622 } 623 624 /* 625 * Setup TLS for main thread. This must be done after the 626 * relocations are processed, since tls initialization section 627 * might be the subject for relocations. 628 */ 629 dbg("initializing initial thread local storage"); 630 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 631 632 dbg("initializing key program variables"); 633 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 634 set_program_var("environ", env); 635 set_program_var("__elf_aux_vector", aux); 636 637 /* Make a list of init functions to call. */ 638 objlist_init(&initlist); 639 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 640 preload_tail, &initlist); 641 642 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 643 644 map_stacks_exec(NULL); 645 ifunc_init(aux); 646 647 dbg("resolving ifuncs"); 648 if (resolve_objects_ifunc(obj_main, 649 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 650 NULL) == -1) 651 rtld_die(); 652 653 if (!obj_main->crt_no_init) { 654 /* 655 * Make sure we don't call the main program's init and fini 656 * functions for binaries linked with old crt1 which calls 657 * _init itself. 658 */ 659 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 660 obj_main->preinit_array = obj_main->init_array = 661 obj_main->fini_array = (Elf_Addr)NULL; 662 } 663 664 wlock_acquire(rtld_bind_lock, &lockstate); 665 if (obj_main->crt_no_init) 666 preinit_main(); 667 objlist_call_init(&initlist, &lockstate); 668 _r_debug_postinit(&obj_main->linkmap); 669 objlist_clear(&initlist); 670 dbg("loading filtees"); 671 TAILQ_FOREACH(obj, &obj_list, next) { 672 if (obj->marker) 673 continue; 674 if (ld_loadfltr || obj->z_loadfltr) 675 load_filtees(obj, 0, &lockstate); 676 } 677 lock_release(rtld_bind_lock, &lockstate); 678 679 dbg("transferring control to program entry point = %p", obj_main->entry); 680 681 /* Return the exit procedure and the program entry point. */ 682 *exit_proc = rtld_exit; 683 *objp = obj_main; 684 return (func_ptr_type) obj_main->entry; 685 } 686 687 void * 688 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 689 { 690 void *ptr; 691 Elf_Addr target; 692 693 ptr = (void *)make_function_pointer(def, obj); 694 target = call_ifunc_resolver(ptr); 695 return ((void *)target); 696 } 697 698 Elf_Addr 699 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 700 { 701 const Elf_Rel *rel; 702 const Elf_Sym *def; 703 const Obj_Entry *defobj; 704 Elf_Addr *where; 705 Elf_Addr target; 706 RtldLockState lockstate; 707 708 rlock_acquire(rtld_bind_lock, &lockstate); 709 if (sigsetjmp(lockstate.env, 0) != 0) 710 lock_upgrade(rtld_bind_lock, &lockstate); 711 if (obj->pltrel) 712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 713 else 714 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 715 716 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 717 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 718 NULL, &lockstate); 719 if (def == NULL) 720 rtld_die(); 721 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 722 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 723 else 724 target = (Elf_Addr)(defobj->relocbase + def->st_value); 725 726 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 727 defobj->strtab + def->st_name, basename(obj->path), 728 (void *)target, basename(defobj->path)); 729 730 /* 731 * Write the new contents for the jmpslot. Note that depending on 732 * architecture, the value which we need to return back to the 733 * lazy binding trampoline may or may not be the target 734 * address. The value returned from reloc_jmpslot() is the value 735 * that the trampoline needs. 736 */ 737 target = reloc_jmpslot(where, target, defobj, obj, rel); 738 lock_release(rtld_bind_lock, &lockstate); 739 return target; 740 } 741 742 /* 743 * Error reporting function. Use it like printf. If formats the message 744 * into a buffer, and sets things up so that the next call to dlerror() 745 * will return the message. 746 */ 747 void 748 _rtld_error(const char *fmt, ...) 749 { 750 static char buf[512]; 751 va_list ap; 752 753 va_start(ap, fmt); 754 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 755 error_message = buf; 756 va_end(ap); 757 } 758 759 /* 760 * Return a dynamically-allocated copy of the current error message, if any. 761 */ 762 static char * 763 errmsg_save(void) 764 { 765 return error_message == NULL ? NULL : xstrdup(error_message); 766 } 767 768 /* 769 * Restore the current error message from a copy which was previously saved 770 * by errmsg_save(). The copy is freed. 771 */ 772 static void 773 errmsg_restore(char *saved_msg) 774 { 775 if (saved_msg == NULL) 776 error_message = NULL; 777 else { 778 _rtld_error("%s", saved_msg); 779 free(saved_msg); 780 } 781 } 782 783 static const char * 784 basename(const char *name) 785 { 786 const char *p = strrchr(name, '/'); 787 return p != NULL ? p + 1 : name; 788 } 789 790 static struct utsname uts; 791 792 static char * 793 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 794 const char *subst, bool may_free) 795 { 796 char *p, *p1, *res, *resp; 797 int subst_len, kw_len, subst_count, old_len, new_len; 798 799 kw_len = strlen(kw); 800 801 /* 802 * First, count the number of the keyword occurrences, to 803 * preallocate the final string. 804 */ 805 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 806 p1 = strstr(p, kw); 807 if (p1 == NULL) 808 break; 809 } 810 811 /* 812 * If the keyword is not found, just return. 813 * 814 * Return non-substituted string if resolution failed. We 815 * cannot do anything more reasonable, the failure mode of the 816 * caller is unresolved library anyway. 817 */ 818 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 819 return (may_free ? real : xstrdup(real)); 820 if (obj != NULL) 821 subst = obj->origin_path; 822 823 /* 824 * There is indeed something to substitute. Calculate the 825 * length of the resulting string, and allocate it. 826 */ 827 subst_len = strlen(subst); 828 old_len = strlen(real); 829 new_len = old_len + (subst_len - kw_len) * subst_count; 830 res = xmalloc(new_len + 1); 831 832 /* 833 * Now, execute the substitution loop. 834 */ 835 for (p = real, resp = res, *resp = '\0';;) { 836 p1 = strstr(p, kw); 837 if (p1 != NULL) { 838 /* Copy the prefix before keyword. */ 839 memcpy(resp, p, p1 - p); 840 resp += p1 - p; 841 /* Keyword replacement. */ 842 memcpy(resp, subst, subst_len); 843 resp += subst_len; 844 *resp = '\0'; 845 p = p1 + kw_len; 846 } else 847 break; 848 } 849 850 /* Copy to the end of string and finish. */ 851 strcat(resp, p); 852 if (may_free) 853 free(real); 854 return (res); 855 } 856 857 static char * 858 origin_subst(Obj_Entry *obj, char *real) 859 { 860 char *res1, *res2, *res3, *res4; 861 862 if (obj == NULL || !trust) 863 return (xstrdup(real)); 864 if (uts.sysname[0] == '\0') { 865 if (uname(&uts) != 0) { 866 _rtld_error("utsname failed: %d", errno); 867 return (NULL); 868 } 869 } 870 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 871 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 872 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 873 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 874 return (res4); 875 } 876 877 void 878 rtld_die(void) 879 { 880 const char *msg = dlerror(); 881 882 if (msg == NULL) 883 msg = "Fatal error"; 884 rtld_fdputstr(STDERR_FILENO, msg); 885 rtld_fdputchar(STDERR_FILENO, '\n'); 886 _exit(1); 887 } 888 889 /* 890 * Process a shared object's DYNAMIC section, and save the important 891 * information in its Obj_Entry structure. 892 */ 893 static void 894 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 895 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 896 { 897 const Elf_Dyn *dynp; 898 Needed_Entry **needed_tail = &obj->needed; 899 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 900 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 901 const Elf_Hashelt *hashtab; 902 const Elf32_Word *hashval; 903 Elf32_Word bkt, nmaskwords; 904 int bloom_size32; 905 int plttype = DT_REL; 906 907 *dyn_rpath = NULL; 908 *dyn_soname = NULL; 909 *dyn_runpath = NULL; 910 911 obj->bind_now = false; 912 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 913 switch (dynp->d_tag) { 914 915 case DT_REL: 916 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 917 break; 918 919 case DT_RELSZ: 920 obj->relsize = dynp->d_un.d_val; 921 break; 922 923 case DT_RELENT: 924 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 925 break; 926 927 case DT_JMPREL: 928 obj->pltrel = (const Elf_Rel *) 929 (obj->relocbase + dynp->d_un.d_ptr); 930 break; 931 932 case DT_PLTRELSZ: 933 obj->pltrelsize = dynp->d_un.d_val; 934 break; 935 936 case DT_RELA: 937 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 938 break; 939 940 case DT_RELASZ: 941 obj->relasize = dynp->d_un.d_val; 942 break; 943 944 case DT_RELAENT: 945 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 946 break; 947 948 case DT_PLTREL: 949 plttype = dynp->d_un.d_val; 950 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 951 break; 952 953 case DT_SYMTAB: 954 obj->symtab = (const Elf_Sym *) 955 (obj->relocbase + dynp->d_un.d_ptr); 956 break; 957 958 case DT_SYMENT: 959 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 960 break; 961 962 case DT_STRTAB: 963 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 964 break; 965 966 case DT_STRSZ: 967 obj->strsize = dynp->d_un.d_val; 968 break; 969 970 case DT_VERNEED: 971 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 972 dynp->d_un.d_val); 973 break; 974 975 case DT_VERNEEDNUM: 976 obj->verneednum = dynp->d_un.d_val; 977 break; 978 979 case DT_VERDEF: 980 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 981 dynp->d_un.d_val); 982 break; 983 984 case DT_VERDEFNUM: 985 obj->verdefnum = dynp->d_un.d_val; 986 break; 987 988 case DT_VERSYM: 989 obj->versyms = (const Elf_Versym *)(obj->relocbase + 990 dynp->d_un.d_val); 991 break; 992 993 case DT_HASH: 994 { 995 hashtab = (const Elf_Hashelt *)(obj->relocbase + 996 dynp->d_un.d_ptr); 997 obj->nbuckets = hashtab[0]; 998 obj->nchains = hashtab[1]; 999 obj->buckets = hashtab + 2; 1000 obj->chains = obj->buckets + obj->nbuckets; 1001 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1002 obj->buckets != NULL; 1003 } 1004 break; 1005 1006 case DT_GNU_HASH: 1007 { 1008 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1009 dynp->d_un.d_ptr); 1010 obj->nbuckets_gnu = hashtab[0]; 1011 obj->symndx_gnu = hashtab[1]; 1012 nmaskwords = hashtab[2]; 1013 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1014 obj->maskwords_bm_gnu = nmaskwords - 1; 1015 obj->shift2_gnu = hashtab[3]; 1016 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1017 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1018 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1019 obj->symndx_gnu; 1020 /* Number of bitmask words is required to be power of 2 */ 1021 obj->valid_hash_gnu = powerof2(nmaskwords) && 1022 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1023 } 1024 break; 1025 1026 case DT_NEEDED: 1027 if (!obj->rtld) { 1028 Needed_Entry *nep = NEW(Needed_Entry); 1029 nep->name = dynp->d_un.d_val; 1030 nep->obj = NULL; 1031 nep->next = NULL; 1032 1033 *needed_tail = nep; 1034 needed_tail = &nep->next; 1035 } 1036 break; 1037 1038 case DT_FILTER: 1039 if (!obj->rtld) { 1040 Needed_Entry *nep = NEW(Needed_Entry); 1041 nep->name = dynp->d_un.d_val; 1042 nep->obj = NULL; 1043 nep->next = NULL; 1044 1045 *needed_filtees_tail = nep; 1046 needed_filtees_tail = &nep->next; 1047 } 1048 break; 1049 1050 case DT_AUXILIARY: 1051 if (!obj->rtld) { 1052 Needed_Entry *nep = NEW(Needed_Entry); 1053 nep->name = dynp->d_un.d_val; 1054 nep->obj = NULL; 1055 nep->next = NULL; 1056 1057 *needed_aux_filtees_tail = nep; 1058 needed_aux_filtees_tail = &nep->next; 1059 } 1060 break; 1061 1062 case DT_PLTGOT: 1063 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1064 break; 1065 1066 case DT_TEXTREL: 1067 obj->textrel = true; 1068 break; 1069 1070 case DT_SYMBOLIC: 1071 obj->symbolic = true; 1072 break; 1073 1074 case DT_RPATH: 1075 /* 1076 * We have to wait until later to process this, because we 1077 * might not have gotten the address of the string table yet. 1078 */ 1079 *dyn_rpath = dynp; 1080 break; 1081 1082 case DT_SONAME: 1083 *dyn_soname = dynp; 1084 break; 1085 1086 case DT_RUNPATH: 1087 *dyn_runpath = dynp; 1088 break; 1089 1090 case DT_INIT: 1091 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1092 break; 1093 1094 case DT_PREINIT_ARRAY: 1095 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1096 break; 1097 1098 case DT_PREINIT_ARRAYSZ: 1099 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1100 break; 1101 1102 case DT_INIT_ARRAY: 1103 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1104 break; 1105 1106 case DT_INIT_ARRAYSZ: 1107 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1108 break; 1109 1110 case DT_FINI: 1111 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1112 break; 1113 1114 case DT_FINI_ARRAY: 1115 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1116 break; 1117 1118 case DT_FINI_ARRAYSZ: 1119 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1120 break; 1121 1122 /* 1123 * Don't process DT_DEBUG on MIPS as the dynamic section 1124 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1125 */ 1126 1127 #ifndef __mips__ 1128 case DT_DEBUG: 1129 if (!early) 1130 dbg("Filling in DT_DEBUG entry"); 1131 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1132 break; 1133 #endif 1134 1135 case DT_FLAGS: 1136 if (dynp->d_un.d_val & DF_ORIGIN) 1137 obj->z_origin = true; 1138 if (dynp->d_un.d_val & DF_SYMBOLIC) 1139 obj->symbolic = true; 1140 if (dynp->d_un.d_val & DF_TEXTREL) 1141 obj->textrel = true; 1142 if (dynp->d_un.d_val & DF_BIND_NOW) 1143 obj->bind_now = true; 1144 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1145 ;*/ 1146 break; 1147 #ifdef __mips__ 1148 case DT_MIPS_LOCAL_GOTNO: 1149 obj->local_gotno = dynp->d_un.d_val; 1150 break; 1151 1152 case DT_MIPS_SYMTABNO: 1153 obj->symtabno = dynp->d_un.d_val; 1154 break; 1155 1156 case DT_MIPS_GOTSYM: 1157 obj->gotsym = dynp->d_un.d_val; 1158 break; 1159 1160 case DT_MIPS_RLD_MAP: 1161 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1162 break; 1163 #endif 1164 1165 #ifdef __powerpc64__ 1166 case DT_PPC64_GLINK: 1167 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1168 break; 1169 #endif 1170 1171 case DT_FLAGS_1: 1172 if (dynp->d_un.d_val & DF_1_NOOPEN) 1173 obj->z_noopen = true; 1174 if (dynp->d_un.d_val & DF_1_ORIGIN) 1175 obj->z_origin = true; 1176 if (dynp->d_un.d_val & DF_1_GLOBAL) 1177 obj->z_global = true; 1178 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1179 obj->bind_now = true; 1180 if (dynp->d_un.d_val & DF_1_NODELETE) 1181 obj->z_nodelete = true; 1182 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1183 obj->z_loadfltr = true; 1184 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1185 obj->z_interpose = true; 1186 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1187 obj->z_nodeflib = true; 1188 break; 1189 1190 default: 1191 if (!early) { 1192 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1193 (long)dynp->d_tag); 1194 } 1195 break; 1196 } 1197 } 1198 1199 obj->traced = false; 1200 1201 if (plttype == DT_RELA) { 1202 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1203 obj->pltrel = NULL; 1204 obj->pltrelasize = obj->pltrelsize; 1205 obj->pltrelsize = 0; 1206 } 1207 1208 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1209 if (obj->valid_hash_sysv) 1210 obj->dynsymcount = obj->nchains; 1211 else if (obj->valid_hash_gnu) { 1212 obj->dynsymcount = 0; 1213 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1214 if (obj->buckets_gnu[bkt] == 0) 1215 continue; 1216 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1217 do 1218 obj->dynsymcount++; 1219 while ((*hashval++ & 1u) == 0); 1220 } 1221 obj->dynsymcount += obj->symndx_gnu; 1222 } 1223 } 1224 1225 static bool 1226 obj_resolve_origin(Obj_Entry *obj) 1227 { 1228 1229 if (obj->origin_path != NULL) 1230 return (true); 1231 obj->origin_path = xmalloc(PATH_MAX); 1232 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1233 } 1234 1235 static void 1236 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1237 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1238 { 1239 1240 if (obj->z_origin && !obj_resolve_origin(obj)) 1241 rtld_die(); 1242 1243 if (dyn_runpath != NULL) { 1244 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1245 obj->runpath = origin_subst(obj, obj->runpath); 1246 } else if (dyn_rpath != NULL) { 1247 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1248 obj->rpath = origin_subst(obj, obj->rpath); 1249 } 1250 if (dyn_soname != NULL) 1251 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1252 } 1253 1254 static void 1255 digest_dynamic(Obj_Entry *obj, int early) 1256 { 1257 const Elf_Dyn *dyn_rpath; 1258 const Elf_Dyn *dyn_soname; 1259 const Elf_Dyn *dyn_runpath; 1260 1261 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1262 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1263 } 1264 1265 /* 1266 * Process a shared object's program header. This is used only for the 1267 * main program, when the kernel has already loaded the main program 1268 * into memory before calling the dynamic linker. It creates and 1269 * returns an Obj_Entry structure. 1270 */ 1271 static Obj_Entry * 1272 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1273 { 1274 Obj_Entry *obj; 1275 const Elf_Phdr *phlimit = phdr + phnum; 1276 const Elf_Phdr *ph; 1277 Elf_Addr note_start, note_end; 1278 int nsegs = 0; 1279 1280 obj = obj_new(); 1281 for (ph = phdr; ph < phlimit; ph++) { 1282 if (ph->p_type != PT_PHDR) 1283 continue; 1284 1285 obj->phdr = phdr; 1286 obj->phsize = ph->p_memsz; 1287 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1288 break; 1289 } 1290 1291 obj->stack_flags = PF_X | PF_R | PF_W; 1292 1293 for (ph = phdr; ph < phlimit; ph++) { 1294 switch (ph->p_type) { 1295 1296 case PT_INTERP: 1297 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1298 break; 1299 1300 case PT_LOAD: 1301 if (nsegs == 0) { /* First load segment */ 1302 obj->vaddrbase = trunc_page(ph->p_vaddr); 1303 obj->mapbase = obj->vaddrbase + obj->relocbase; 1304 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1305 obj->vaddrbase; 1306 } else { /* Last load segment */ 1307 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1308 obj->vaddrbase; 1309 } 1310 nsegs++; 1311 break; 1312 1313 case PT_DYNAMIC: 1314 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1315 break; 1316 1317 case PT_TLS: 1318 obj->tlsindex = 1; 1319 obj->tlssize = ph->p_memsz; 1320 obj->tlsalign = ph->p_align; 1321 obj->tlsinitsize = ph->p_filesz; 1322 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1323 break; 1324 1325 case PT_GNU_STACK: 1326 obj->stack_flags = ph->p_flags; 1327 break; 1328 1329 case PT_GNU_RELRO: 1330 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1331 obj->relro_size = round_page(ph->p_memsz); 1332 break; 1333 1334 case PT_NOTE: 1335 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1336 note_end = note_start + ph->p_filesz; 1337 digest_notes(obj, note_start, note_end); 1338 break; 1339 } 1340 } 1341 if (nsegs < 1) { 1342 _rtld_error("%s: too few PT_LOAD segments", path); 1343 return NULL; 1344 } 1345 1346 obj->entry = entry; 1347 return obj; 1348 } 1349 1350 void 1351 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1352 { 1353 const Elf_Note *note; 1354 const char *note_name; 1355 uintptr_t p; 1356 1357 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1358 note = (const Elf_Note *)((const char *)(note + 1) + 1359 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1360 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1361 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1362 note->n_descsz != sizeof(int32_t)) 1363 continue; 1364 if (note->n_type != NT_FREEBSD_ABI_TAG && 1365 note->n_type != NT_FREEBSD_NOINIT_TAG) 1366 continue; 1367 note_name = (const char *)(note + 1); 1368 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1369 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1370 continue; 1371 switch (note->n_type) { 1372 case NT_FREEBSD_ABI_TAG: 1373 /* FreeBSD osrel note */ 1374 p = (uintptr_t)(note + 1); 1375 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1376 obj->osrel = *(const int32_t *)(p); 1377 dbg("note osrel %d", obj->osrel); 1378 break; 1379 case NT_FREEBSD_NOINIT_TAG: 1380 /* FreeBSD 'crt does not call init' note */ 1381 obj->crt_no_init = true; 1382 dbg("note crt_no_init"); 1383 break; 1384 } 1385 } 1386 } 1387 1388 static Obj_Entry * 1389 dlcheck(void *handle) 1390 { 1391 Obj_Entry *obj; 1392 1393 TAILQ_FOREACH(obj, &obj_list, next) { 1394 if (obj == (Obj_Entry *) handle) 1395 break; 1396 } 1397 1398 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1399 _rtld_error("Invalid shared object handle %p", handle); 1400 return NULL; 1401 } 1402 return obj; 1403 } 1404 1405 /* 1406 * If the given object is already in the donelist, return true. Otherwise 1407 * add the object to the list and return false. 1408 */ 1409 static bool 1410 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1411 { 1412 unsigned int i; 1413 1414 for (i = 0; i < dlp->num_used; i++) 1415 if (dlp->objs[i] == obj) 1416 return true; 1417 /* 1418 * Our donelist allocation should always be sufficient. But if 1419 * our threads locking isn't working properly, more shared objects 1420 * could have been loaded since we allocated the list. That should 1421 * never happen, but we'll handle it properly just in case it does. 1422 */ 1423 if (dlp->num_used < dlp->num_alloc) 1424 dlp->objs[dlp->num_used++] = obj; 1425 return false; 1426 } 1427 1428 /* 1429 * Hash function for symbol table lookup. Don't even think about changing 1430 * this. It is specified by the System V ABI. 1431 */ 1432 unsigned long 1433 elf_hash(const char *name) 1434 { 1435 const unsigned char *p = (const unsigned char *) name; 1436 unsigned long h = 0; 1437 unsigned long g; 1438 1439 while (*p != '\0') { 1440 h = (h << 4) + *p++; 1441 if ((g = h & 0xf0000000) != 0) 1442 h ^= g >> 24; 1443 h &= ~g; 1444 } 1445 return h; 1446 } 1447 1448 /* 1449 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1450 * unsigned in case it's implemented with a wider type. 1451 */ 1452 static uint32_t 1453 gnu_hash(const char *s) 1454 { 1455 uint32_t h; 1456 unsigned char c; 1457 1458 h = 5381; 1459 for (c = *s; c != '\0'; c = *++s) 1460 h = h * 33 + c; 1461 return (h & 0xffffffff); 1462 } 1463 1464 1465 /* 1466 * Find the library with the given name, and return its full pathname. 1467 * The returned string is dynamically allocated. Generates an error 1468 * message and returns NULL if the library cannot be found. 1469 * 1470 * If the second argument is non-NULL, then it refers to an already- 1471 * loaded shared object, whose library search path will be searched. 1472 * 1473 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1474 * descriptor (which is close-on-exec) will be passed out via the third 1475 * argument. 1476 * 1477 * The search order is: 1478 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1479 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1480 * LD_LIBRARY_PATH 1481 * DT_RUNPATH in the referencing file 1482 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1483 * from list) 1484 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1485 * 1486 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1487 */ 1488 static char * 1489 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1490 { 1491 char *pathname; 1492 char *name; 1493 bool nodeflib, objgiven; 1494 1495 objgiven = refobj != NULL; 1496 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1497 if (xname[0] != '/' && !trust) { 1498 _rtld_error("Absolute pathname required for shared object \"%s\"", 1499 xname); 1500 return NULL; 1501 } 1502 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1503 __DECONST(char *, xname))); 1504 } 1505 1506 if (libmap_disable || !objgiven || 1507 (name = lm_find(refobj->path, xname)) == NULL) 1508 name = (char *)xname; 1509 1510 dbg(" Searching for \"%s\"", name); 1511 1512 /* 1513 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1514 * back to pre-conforming behaviour if user requested so with 1515 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1516 * nodeflib. 1517 */ 1518 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1519 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1520 (refobj != NULL && 1521 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1522 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1523 (pathname = search_library_path(name, gethints(false))) != NULL || 1524 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1525 return (pathname); 1526 } else { 1527 nodeflib = objgiven ? refobj->z_nodeflib : false; 1528 if ((objgiven && 1529 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1530 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1531 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1532 (pathname = search_library_path(name, ld_library_path)) != NULL || 1533 (objgiven && 1534 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1535 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1536 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1537 (objgiven && !nodeflib && 1538 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1539 return (pathname); 1540 } 1541 1542 if (objgiven && refobj->path != NULL) { 1543 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1544 name, basename(refobj->path)); 1545 } else { 1546 _rtld_error("Shared object \"%s\" not found", name); 1547 } 1548 return NULL; 1549 } 1550 1551 /* 1552 * Given a symbol number in a referencing object, find the corresponding 1553 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1554 * no definition was found. Returns a pointer to the Obj_Entry of the 1555 * defining object via the reference parameter DEFOBJ_OUT. 1556 */ 1557 const Elf_Sym * 1558 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1559 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1560 RtldLockState *lockstate) 1561 { 1562 const Elf_Sym *ref; 1563 const Elf_Sym *def; 1564 const Obj_Entry *defobj; 1565 SymLook req; 1566 const char *name; 1567 int res; 1568 1569 /* 1570 * If we have already found this symbol, get the information from 1571 * the cache. 1572 */ 1573 if (symnum >= refobj->dynsymcount) 1574 return NULL; /* Bad object */ 1575 if (cache != NULL && cache[symnum].sym != NULL) { 1576 *defobj_out = cache[symnum].obj; 1577 return cache[symnum].sym; 1578 } 1579 1580 ref = refobj->symtab + symnum; 1581 name = refobj->strtab + ref->st_name; 1582 def = NULL; 1583 defobj = NULL; 1584 1585 /* 1586 * We don't have to do a full scale lookup if the symbol is local. 1587 * We know it will bind to the instance in this load module; to 1588 * which we already have a pointer (ie ref). By not doing a lookup, 1589 * we not only improve performance, but it also avoids unresolvable 1590 * symbols when local symbols are not in the hash table. This has 1591 * been seen with the ia64 toolchain. 1592 */ 1593 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1594 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1595 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1596 symnum); 1597 } 1598 symlook_init(&req, name); 1599 req.flags = flags; 1600 req.ventry = fetch_ventry(refobj, symnum); 1601 req.lockstate = lockstate; 1602 res = symlook_default(&req, refobj); 1603 if (res == 0) { 1604 def = req.sym_out; 1605 defobj = req.defobj_out; 1606 } 1607 } else { 1608 def = ref; 1609 defobj = refobj; 1610 } 1611 1612 /* 1613 * If we found no definition and the reference is weak, treat the 1614 * symbol as having the value zero. 1615 */ 1616 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1617 def = &sym_zero; 1618 defobj = obj_main; 1619 } 1620 1621 if (def != NULL) { 1622 *defobj_out = defobj; 1623 /* Record the information in the cache to avoid subsequent lookups. */ 1624 if (cache != NULL) { 1625 cache[symnum].sym = def; 1626 cache[symnum].obj = defobj; 1627 } 1628 } else { 1629 if (refobj != &obj_rtld) 1630 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1631 } 1632 return def; 1633 } 1634 1635 /* 1636 * Return the search path from the ldconfig hints file, reading it if 1637 * necessary. If nostdlib is true, then the default search paths are 1638 * not added to result. 1639 * 1640 * Returns NULL if there are problems with the hints file, 1641 * or if the search path there is empty. 1642 */ 1643 static const char * 1644 gethints(bool nostdlib) 1645 { 1646 static char *hints, *filtered_path; 1647 static struct elfhints_hdr hdr; 1648 struct fill_search_info_args sargs, hargs; 1649 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1650 struct dl_serpath *SLPpath, *hintpath; 1651 char *p; 1652 struct stat hint_stat; 1653 unsigned int SLPndx, hintndx, fndx, fcount; 1654 int fd; 1655 size_t flen; 1656 uint32_t dl; 1657 bool skip; 1658 1659 /* First call, read the hints file */ 1660 if (hints == NULL) { 1661 /* Keep from trying again in case the hints file is bad. */ 1662 hints = ""; 1663 1664 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1665 return (NULL); 1666 1667 /* 1668 * Check of hdr.dirlistlen value against type limit 1669 * intends to pacify static analyzers. Further 1670 * paranoia leads to checks that dirlist is fully 1671 * contained in the file range. 1672 */ 1673 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1674 hdr.magic != ELFHINTS_MAGIC || 1675 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1676 fstat(fd, &hint_stat) == -1) { 1677 cleanup1: 1678 close(fd); 1679 hdr.dirlistlen = 0; 1680 return (NULL); 1681 } 1682 dl = hdr.strtab; 1683 if (dl + hdr.dirlist < dl) 1684 goto cleanup1; 1685 dl += hdr.dirlist; 1686 if (dl + hdr.dirlistlen < dl) 1687 goto cleanup1; 1688 dl += hdr.dirlistlen; 1689 if (dl > hint_stat.st_size) 1690 goto cleanup1; 1691 p = xmalloc(hdr.dirlistlen + 1); 1692 1693 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1694 read(fd, p, hdr.dirlistlen + 1) != 1695 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1696 free(p); 1697 goto cleanup1; 1698 } 1699 hints = p; 1700 close(fd); 1701 } 1702 1703 /* 1704 * If caller agreed to receive list which includes the default 1705 * paths, we are done. Otherwise, if we still did not 1706 * calculated filtered result, do it now. 1707 */ 1708 if (!nostdlib) 1709 return (hints[0] != '\0' ? hints : NULL); 1710 if (filtered_path != NULL) 1711 goto filt_ret; 1712 1713 /* 1714 * Obtain the list of all configured search paths, and the 1715 * list of the default paths. 1716 * 1717 * First estimate the size of the results. 1718 */ 1719 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1720 smeta.dls_cnt = 0; 1721 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1722 hmeta.dls_cnt = 0; 1723 1724 sargs.request = RTLD_DI_SERINFOSIZE; 1725 sargs.serinfo = &smeta; 1726 hargs.request = RTLD_DI_SERINFOSIZE; 1727 hargs.serinfo = &hmeta; 1728 1729 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1730 path_enumerate(hints, fill_search_info, &hargs); 1731 1732 SLPinfo = xmalloc(smeta.dls_size); 1733 hintinfo = xmalloc(hmeta.dls_size); 1734 1735 /* 1736 * Next fetch both sets of paths. 1737 */ 1738 sargs.request = RTLD_DI_SERINFO; 1739 sargs.serinfo = SLPinfo; 1740 sargs.serpath = &SLPinfo->dls_serpath[0]; 1741 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1742 1743 hargs.request = RTLD_DI_SERINFO; 1744 hargs.serinfo = hintinfo; 1745 hargs.serpath = &hintinfo->dls_serpath[0]; 1746 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1747 1748 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1749 path_enumerate(hints, fill_search_info, &hargs); 1750 1751 /* 1752 * Now calculate the difference between two sets, by excluding 1753 * standard paths from the full set. 1754 */ 1755 fndx = 0; 1756 fcount = 0; 1757 filtered_path = xmalloc(hdr.dirlistlen + 1); 1758 hintpath = &hintinfo->dls_serpath[0]; 1759 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1760 skip = false; 1761 SLPpath = &SLPinfo->dls_serpath[0]; 1762 /* 1763 * Check each standard path against current. 1764 */ 1765 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1766 /* matched, skip the path */ 1767 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1768 skip = true; 1769 break; 1770 } 1771 } 1772 if (skip) 1773 continue; 1774 /* 1775 * Not matched against any standard path, add the path 1776 * to result. Separate consequtive paths with ':'. 1777 */ 1778 if (fcount > 0) { 1779 filtered_path[fndx] = ':'; 1780 fndx++; 1781 } 1782 fcount++; 1783 flen = strlen(hintpath->dls_name); 1784 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1785 fndx += flen; 1786 } 1787 filtered_path[fndx] = '\0'; 1788 1789 free(SLPinfo); 1790 free(hintinfo); 1791 1792 filt_ret: 1793 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1794 } 1795 1796 static void 1797 init_dag(Obj_Entry *root) 1798 { 1799 const Needed_Entry *needed; 1800 const Objlist_Entry *elm; 1801 DoneList donelist; 1802 1803 if (root->dag_inited) 1804 return; 1805 donelist_init(&donelist); 1806 1807 /* Root object belongs to own DAG. */ 1808 objlist_push_tail(&root->dldags, root); 1809 objlist_push_tail(&root->dagmembers, root); 1810 donelist_check(&donelist, root); 1811 1812 /* 1813 * Add dependencies of root object to DAG in breadth order 1814 * by exploiting the fact that each new object get added 1815 * to the tail of the dagmembers list. 1816 */ 1817 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1818 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1819 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1820 continue; 1821 objlist_push_tail(&needed->obj->dldags, root); 1822 objlist_push_tail(&root->dagmembers, needed->obj); 1823 } 1824 } 1825 root->dag_inited = true; 1826 } 1827 1828 Obj_Entry * 1829 globallist_curr(const Obj_Entry *obj) 1830 { 1831 1832 for (;;) { 1833 if (obj == NULL) 1834 return (NULL); 1835 if (!obj->marker) 1836 return (__DECONST(Obj_Entry *, obj)); 1837 obj = TAILQ_PREV(obj, obj_entry_q, next); 1838 } 1839 } 1840 1841 Obj_Entry * 1842 globallist_next(const Obj_Entry *obj) 1843 { 1844 1845 for (;;) { 1846 obj = TAILQ_NEXT(obj, next); 1847 if (obj == NULL) 1848 return (NULL); 1849 if (!obj->marker) 1850 return (__DECONST(Obj_Entry *, obj)); 1851 } 1852 } 1853 1854 static void 1855 process_z(Obj_Entry *root) 1856 { 1857 const Objlist_Entry *elm; 1858 Obj_Entry *obj; 1859 1860 /* 1861 * Walk over object DAG and process every dependent object 1862 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1863 * to grow their own DAG. 1864 * 1865 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1866 * symlook_global() to work. 1867 * 1868 * For DF_1_NODELETE, the DAG should have its reference upped. 1869 */ 1870 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1871 obj = elm->obj; 1872 if (obj == NULL) 1873 continue; 1874 if (obj->z_nodelete && !obj->ref_nodel) { 1875 dbg("obj %s -z nodelete", obj->path); 1876 init_dag(obj); 1877 ref_dag(obj); 1878 obj->ref_nodel = true; 1879 } 1880 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1881 dbg("obj %s -z global", obj->path); 1882 objlist_push_tail(&list_global, obj); 1883 init_dag(obj); 1884 } 1885 } 1886 } 1887 /* 1888 * Initialize the dynamic linker. The argument is the address at which 1889 * the dynamic linker has been mapped into memory. The primary task of 1890 * this function is to relocate the dynamic linker. 1891 */ 1892 static void 1893 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1894 { 1895 Obj_Entry objtmp; /* Temporary rtld object */ 1896 const Elf_Ehdr *ehdr; 1897 const Elf_Dyn *dyn_rpath; 1898 const Elf_Dyn *dyn_soname; 1899 const Elf_Dyn *dyn_runpath; 1900 1901 #ifdef RTLD_INIT_PAGESIZES_EARLY 1902 /* The page size is required by the dynamic memory allocator. */ 1903 init_pagesizes(aux_info); 1904 #endif 1905 1906 /* 1907 * Conjure up an Obj_Entry structure for the dynamic linker. 1908 * 1909 * The "path" member can't be initialized yet because string constants 1910 * cannot yet be accessed. Below we will set it correctly. 1911 */ 1912 memset(&objtmp, 0, sizeof(objtmp)); 1913 objtmp.path = NULL; 1914 objtmp.rtld = true; 1915 objtmp.mapbase = mapbase; 1916 #ifdef PIC 1917 objtmp.relocbase = mapbase; 1918 #endif 1919 if (RTLD_IS_DYNAMIC()) { 1920 objtmp.dynamic = rtld_dynamic(&objtmp); 1921 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1922 assert(objtmp.needed == NULL); 1923 #if !defined(__mips__) 1924 /* MIPS has a bogus DT_TEXTREL. */ 1925 assert(!objtmp.textrel); 1926 #endif 1927 1928 /* 1929 * Temporarily put the dynamic linker entry into the object list, so 1930 * that symbols can be found. 1931 */ 1932 1933 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1934 } 1935 ehdr = (Elf_Ehdr *)mapbase; 1936 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1937 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1938 1939 /* Initialize the object list. */ 1940 TAILQ_INIT(&obj_list); 1941 1942 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1943 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1944 1945 #ifndef RTLD_INIT_PAGESIZES_EARLY 1946 /* The page size is required by the dynamic memory allocator. */ 1947 init_pagesizes(aux_info); 1948 #endif 1949 1950 if (aux_info[AT_OSRELDATE] != NULL) 1951 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1952 1953 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1954 1955 /* Replace the path with a dynamically allocated copy. */ 1956 obj_rtld.path = xstrdup(ld_path_rtld); 1957 1958 r_debug.r_brk = r_debug_state; 1959 r_debug.r_state = RT_CONSISTENT; 1960 } 1961 1962 /* 1963 * Retrieve the array of supported page sizes. The kernel provides the page 1964 * sizes in increasing order. 1965 */ 1966 static void 1967 init_pagesizes(Elf_Auxinfo **aux_info) 1968 { 1969 static size_t psa[MAXPAGESIZES]; 1970 int mib[2]; 1971 size_t len, size; 1972 1973 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1974 NULL) { 1975 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1976 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1977 } else { 1978 len = 2; 1979 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1980 size = sizeof(psa); 1981 else { 1982 /* As a fallback, retrieve the base page size. */ 1983 size = sizeof(psa[0]); 1984 if (aux_info[AT_PAGESZ] != NULL) { 1985 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1986 goto psa_filled; 1987 } else { 1988 mib[0] = CTL_HW; 1989 mib[1] = HW_PAGESIZE; 1990 len = 2; 1991 } 1992 } 1993 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1994 _rtld_error("sysctl for hw.pagesize(s) failed"); 1995 rtld_die(); 1996 } 1997 psa_filled: 1998 pagesizes = psa; 1999 } 2000 npagesizes = size / sizeof(pagesizes[0]); 2001 /* Discard any invalid entries at the end of the array. */ 2002 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2003 npagesizes--; 2004 } 2005 2006 /* 2007 * Add the init functions from a needed object list (and its recursive 2008 * needed objects) to "list". This is not used directly; it is a helper 2009 * function for initlist_add_objects(). The write lock must be held 2010 * when this function is called. 2011 */ 2012 static void 2013 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2014 { 2015 /* Recursively process the successor needed objects. */ 2016 if (needed->next != NULL) 2017 initlist_add_neededs(needed->next, list); 2018 2019 /* Process the current needed object. */ 2020 if (needed->obj != NULL) 2021 initlist_add_objects(needed->obj, needed->obj, list); 2022 } 2023 2024 /* 2025 * Scan all of the DAGs rooted in the range of objects from "obj" to 2026 * "tail" and add their init functions to "list". This recurses over 2027 * the DAGs and ensure the proper init ordering such that each object's 2028 * needed libraries are initialized before the object itself. At the 2029 * same time, this function adds the objects to the global finalization 2030 * list "list_fini" in the opposite order. The write lock must be 2031 * held when this function is called. 2032 */ 2033 static void 2034 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2035 { 2036 Obj_Entry *nobj; 2037 2038 if (obj->init_scanned || obj->init_done) 2039 return; 2040 obj->init_scanned = true; 2041 2042 /* Recursively process the successor objects. */ 2043 nobj = globallist_next(obj); 2044 if (nobj != NULL && obj != tail) 2045 initlist_add_objects(nobj, tail, list); 2046 2047 /* Recursively process the needed objects. */ 2048 if (obj->needed != NULL) 2049 initlist_add_neededs(obj->needed, list); 2050 if (obj->needed_filtees != NULL) 2051 initlist_add_neededs(obj->needed_filtees, list); 2052 if (obj->needed_aux_filtees != NULL) 2053 initlist_add_neededs(obj->needed_aux_filtees, list); 2054 2055 /* Add the object to the init list. */ 2056 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2057 obj->init_array != (Elf_Addr)NULL) 2058 objlist_push_tail(list, obj); 2059 2060 /* Add the object to the global fini list in the reverse order. */ 2061 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2062 && !obj->on_fini_list) { 2063 objlist_push_head(&list_fini, obj); 2064 obj->on_fini_list = true; 2065 } 2066 } 2067 2068 #ifndef FPTR_TARGET 2069 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2070 #endif 2071 2072 static void 2073 free_needed_filtees(Needed_Entry *n) 2074 { 2075 Needed_Entry *needed, *needed1; 2076 2077 for (needed = n; needed != NULL; needed = needed->next) { 2078 if (needed->obj != NULL) { 2079 dlclose(needed->obj); 2080 needed->obj = NULL; 2081 } 2082 } 2083 for (needed = n; needed != NULL; needed = needed1) { 2084 needed1 = needed->next; 2085 free(needed); 2086 } 2087 } 2088 2089 static void 2090 unload_filtees(Obj_Entry *obj) 2091 { 2092 2093 free_needed_filtees(obj->needed_filtees); 2094 obj->needed_filtees = NULL; 2095 free_needed_filtees(obj->needed_aux_filtees); 2096 obj->needed_aux_filtees = NULL; 2097 obj->filtees_loaded = false; 2098 } 2099 2100 static void 2101 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2102 RtldLockState *lockstate) 2103 { 2104 2105 for (; needed != NULL; needed = needed->next) { 2106 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2107 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2108 RTLD_LOCAL, lockstate); 2109 } 2110 } 2111 2112 static void 2113 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2114 { 2115 2116 lock_restart_for_upgrade(lockstate); 2117 if (!obj->filtees_loaded) { 2118 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2119 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2120 obj->filtees_loaded = true; 2121 } 2122 } 2123 2124 static int 2125 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2126 { 2127 Obj_Entry *obj1; 2128 2129 for (; needed != NULL; needed = needed->next) { 2130 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2131 flags & ~RTLD_LO_NOLOAD); 2132 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2133 return (-1); 2134 } 2135 return (0); 2136 } 2137 2138 /* 2139 * Given a shared object, traverse its list of needed objects, and load 2140 * each of them. Returns 0 on success. Generates an error message and 2141 * returns -1 on failure. 2142 */ 2143 static int 2144 load_needed_objects(Obj_Entry *first, int flags) 2145 { 2146 Obj_Entry *obj; 2147 2148 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2149 if (obj->marker) 2150 continue; 2151 if (process_needed(obj, obj->needed, flags) == -1) 2152 return (-1); 2153 } 2154 return (0); 2155 } 2156 2157 static int 2158 load_preload_objects(void) 2159 { 2160 char *p = ld_preload; 2161 Obj_Entry *obj; 2162 static const char delim[] = " \t:;"; 2163 2164 if (p == NULL) 2165 return 0; 2166 2167 p += strspn(p, delim); 2168 while (*p != '\0') { 2169 size_t len = strcspn(p, delim); 2170 char savech; 2171 2172 savech = p[len]; 2173 p[len] = '\0'; 2174 obj = load_object(p, -1, NULL, 0); 2175 if (obj == NULL) 2176 return -1; /* XXX - cleanup */ 2177 obj->z_interpose = true; 2178 p[len] = savech; 2179 p += len; 2180 p += strspn(p, delim); 2181 } 2182 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2183 return 0; 2184 } 2185 2186 static const char * 2187 printable_path(const char *path) 2188 { 2189 2190 return (path == NULL ? "<unknown>" : path); 2191 } 2192 2193 /* 2194 * Load a shared object into memory, if it is not already loaded. The 2195 * object may be specified by name or by user-supplied file descriptor 2196 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2197 * duplicate is. 2198 * 2199 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2200 * on failure. 2201 */ 2202 static Obj_Entry * 2203 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2204 { 2205 Obj_Entry *obj; 2206 int fd; 2207 struct stat sb; 2208 char *path; 2209 2210 fd = -1; 2211 if (name != NULL) { 2212 TAILQ_FOREACH(obj, &obj_list, next) { 2213 if (obj->marker) 2214 continue; 2215 if (object_match_name(obj, name)) 2216 return (obj); 2217 } 2218 2219 path = find_library(name, refobj, &fd); 2220 if (path == NULL) 2221 return (NULL); 2222 } else 2223 path = NULL; 2224 2225 if (fd >= 0) { 2226 /* 2227 * search_library_pathfds() opens a fresh file descriptor for the 2228 * library, so there is no need to dup(). 2229 */ 2230 } else if (fd_u == -1) { 2231 /* 2232 * If we didn't find a match by pathname, or the name is not 2233 * supplied, open the file and check again by device and inode. 2234 * This avoids false mismatches caused by multiple links or ".." 2235 * in pathnames. 2236 * 2237 * To avoid a race, we open the file and use fstat() rather than 2238 * using stat(). 2239 */ 2240 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2241 _rtld_error("Cannot open \"%s\"", path); 2242 free(path); 2243 return (NULL); 2244 } 2245 } else { 2246 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2247 if (fd == -1) { 2248 _rtld_error("Cannot dup fd"); 2249 free(path); 2250 return (NULL); 2251 } 2252 } 2253 if (fstat(fd, &sb) == -1) { 2254 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2255 close(fd); 2256 free(path); 2257 return NULL; 2258 } 2259 TAILQ_FOREACH(obj, &obj_list, next) { 2260 if (obj->marker) 2261 continue; 2262 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2263 break; 2264 } 2265 if (obj != NULL && name != NULL) { 2266 object_add_name(obj, name); 2267 free(path); 2268 close(fd); 2269 return obj; 2270 } 2271 if (flags & RTLD_LO_NOLOAD) { 2272 free(path); 2273 close(fd); 2274 return (NULL); 2275 } 2276 2277 /* First use of this object, so we must map it in */ 2278 obj = do_load_object(fd, name, path, &sb, flags); 2279 if (obj == NULL) 2280 free(path); 2281 close(fd); 2282 2283 return obj; 2284 } 2285 2286 static Obj_Entry * 2287 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2288 int flags) 2289 { 2290 Obj_Entry *obj; 2291 struct statfs fs; 2292 2293 /* 2294 * but first, make sure that environment variables haven't been 2295 * used to circumvent the noexec flag on a filesystem. 2296 */ 2297 if (dangerous_ld_env) { 2298 if (fstatfs(fd, &fs) != 0) { 2299 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2300 return NULL; 2301 } 2302 if (fs.f_flags & MNT_NOEXEC) { 2303 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2304 return NULL; 2305 } 2306 } 2307 dbg("loading \"%s\"", printable_path(path)); 2308 obj = map_object(fd, printable_path(path), sbp); 2309 if (obj == NULL) 2310 return NULL; 2311 2312 /* 2313 * If DT_SONAME is present in the object, digest_dynamic2 already 2314 * added it to the object names. 2315 */ 2316 if (name != NULL) 2317 object_add_name(obj, name); 2318 obj->path = path; 2319 digest_dynamic(obj, 0); 2320 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2321 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2322 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2323 RTLD_LO_DLOPEN) { 2324 dbg("refusing to load non-loadable \"%s\"", obj->path); 2325 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2326 munmap(obj->mapbase, obj->mapsize); 2327 obj_free(obj); 2328 return (NULL); 2329 } 2330 2331 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2332 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2333 obj_count++; 2334 obj_loads++; 2335 linkmap_add(obj); /* for GDB & dlinfo() */ 2336 max_stack_flags |= obj->stack_flags; 2337 2338 dbg(" %p .. %p: %s", obj->mapbase, 2339 obj->mapbase + obj->mapsize - 1, obj->path); 2340 if (obj->textrel) 2341 dbg(" WARNING: %s has impure text", obj->path); 2342 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2343 obj->path); 2344 2345 return obj; 2346 } 2347 2348 static Obj_Entry * 2349 obj_from_addr(const void *addr) 2350 { 2351 Obj_Entry *obj; 2352 2353 TAILQ_FOREACH(obj, &obj_list, next) { 2354 if (obj->marker) 2355 continue; 2356 if (addr < (void *) obj->mapbase) 2357 continue; 2358 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2359 return obj; 2360 } 2361 return NULL; 2362 } 2363 2364 static void 2365 preinit_main(void) 2366 { 2367 Elf_Addr *preinit_addr; 2368 int index; 2369 2370 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2371 if (preinit_addr == NULL) 2372 return; 2373 2374 for (index = 0; index < obj_main->preinit_array_num; index++) { 2375 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2376 dbg("calling preinit function for %s at %p", obj_main->path, 2377 (void *)preinit_addr[index]); 2378 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2379 0, 0, obj_main->path); 2380 call_init_pointer(obj_main, preinit_addr[index]); 2381 } 2382 } 2383 } 2384 2385 /* 2386 * Call the finalization functions for each of the objects in "list" 2387 * belonging to the DAG of "root" and referenced once. If NULL "root" 2388 * is specified, every finalization function will be called regardless 2389 * of the reference count and the list elements won't be freed. All of 2390 * the objects are expected to have non-NULL fini functions. 2391 */ 2392 static void 2393 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2394 { 2395 Objlist_Entry *elm; 2396 char *saved_msg; 2397 Elf_Addr *fini_addr; 2398 int index; 2399 2400 assert(root == NULL || root->refcount == 1); 2401 2402 /* 2403 * Preserve the current error message since a fini function might 2404 * call into the dynamic linker and overwrite it. 2405 */ 2406 saved_msg = errmsg_save(); 2407 do { 2408 STAILQ_FOREACH(elm, list, link) { 2409 if (root != NULL && (elm->obj->refcount != 1 || 2410 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2411 continue; 2412 /* Remove object from fini list to prevent recursive invocation. */ 2413 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2414 /* 2415 * XXX: If a dlopen() call references an object while the 2416 * fini function is in progress, we might end up trying to 2417 * unload the referenced object in dlclose() or the object 2418 * won't be unloaded although its fini function has been 2419 * called. 2420 */ 2421 lock_release(rtld_bind_lock, lockstate); 2422 2423 /* 2424 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2425 * When this happens, DT_FINI_ARRAY is processed first. 2426 */ 2427 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2428 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2429 for (index = elm->obj->fini_array_num - 1; index >= 0; 2430 index--) { 2431 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2432 dbg("calling fini function for %s at %p", 2433 elm->obj->path, (void *)fini_addr[index]); 2434 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2435 (void *)fini_addr[index], 0, 0, elm->obj->path); 2436 call_initfini_pointer(elm->obj, fini_addr[index]); 2437 } 2438 } 2439 } 2440 if (elm->obj->fini != (Elf_Addr)NULL) { 2441 dbg("calling fini function for %s at %p", elm->obj->path, 2442 (void *)elm->obj->fini); 2443 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2444 0, 0, elm->obj->path); 2445 call_initfini_pointer(elm->obj, elm->obj->fini); 2446 } 2447 wlock_acquire(rtld_bind_lock, lockstate); 2448 /* No need to free anything if process is going down. */ 2449 if (root != NULL) 2450 free(elm); 2451 /* 2452 * We must restart the list traversal after every fini call 2453 * because a dlclose() call from the fini function or from 2454 * another thread might have modified the reference counts. 2455 */ 2456 break; 2457 } 2458 } while (elm != NULL); 2459 errmsg_restore(saved_msg); 2460 } 2461 2462 /* 2463 * Call the initialization functions for each of the objects in 2464 * "list". All of the objects are expected to have non-NULL init 2465 * functions. 2466 */ 2467 static void 2468 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2469 { 2470 Objlist_Entry *elm; 2471 Obj_Entry *obj; 2472 char *saved_msg; 2473 Elf_Addr *init_addr; 2474 int index; 2475 2476 /* 2477 * Clean init_scanned flag so that objects can be rechecked and 2478 * possibly initialized earlier if any of vectors called below 2479 * cause the change by using dlopen. 2480 */ 2481 TAILQ_FOREACH(obj, &obj_list, next) { 2482 if (obj->marker) 2483 continue; 2484 obj->init_scanned = false; 2485 } 2486 2487 /* 2488 * Preserve the current error message since an init function might 2489 * call into the dynamic linker and overwrite it. 2490 */ 2491 saved_msg = errmsg_save(); 2492 STAILQ_FOREACH(elm, list, link) { 2493 if (elm->obj->init_done) /* Initialized early. */ 2494 continue; 2495 /* 2496 * Race: other thread might try to use this object before current 2497 * one completes the initilization. Not much can be done here 2498 * without better locking. 2499 */ 2500 elm->obj->init_done = true; 2501 lock_release(rtld_bind_lock, lockstate); 2502 2503 /* 2504 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2505 * When this happens, DT_INIT is processed first. 2506 */ 2507 if (elm->obj->init != (Elf_Addr)NULL) { 2508 dbg("calling init function for %s at %p", elm->obj->path, 2509 (void *)elm->obj->init); 2510 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2511 0, 0, elm->obj->path); 2512 call_initfini_pointer(elm->obj, elm->obj->init); 2513 } 2514 init_addr = (Elf_Addr *)elm->obj->init_array; 2515 if (init_addr != NULL) { 2516 for (index = 0; index < elm->obj->init_array_num; index++) { 2517 if (init_addr[index] != 0 && init_addr[index] != 1) { 2518 dbg("calling init function for %s at %p", elm->obj->path, 2519 (void *)init_addr[index]); 2520 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2521 (void *)init_addr[index], 0, 0, elm->obj->path); 2522 call_init_pointer(elm->obj, init_addr[index]); 2523 } 2524 } 2525 } 2526 wlock_acquire(rtld_bind_lock, lockstate); 2527 } 2528 errmsg_restore(saved_msg); 2529 } 2530 2531 static void 2532 objlist_clear(Objlist *list) 2533 { 2534 Objlist_Entry *elm; 2535 2536 while (!STAILQ_EMPTY(list)) { 2537 elm = STAILQ_FIRST(list); 2538 STAILQ_REMOVE_HEAD(list, link); 2539 free(elm); 2540 } 2541 } 2542 2543 static Objlist_Entry * 2544 objlist_find(Objlist *list, const Obj_Entry *obj) 2545 { 2546 Objlist_Entry *elm; 2547 2548 STAILQ_FOREACH(elm, list, link) 2549 if (elm->obj == obj) 2550 return elm; 2551 return NULL; 2552 } 2553 2554 static void 2555 objlist_init(Objlist *list) 2556 { 2557 STAILQ_INIT(list); 2558 } 2559 2560 static void 2561 objlist_push_head(Objlist *list, Obj_Entry *obj) 2562 { 2563 Objlist_Entry *elm; 2564 2565 elm = NEW(Objlist_Entry); 2566 elm->obj = obj; 2567 STAILQ_INSERT_HEAD(list, elm, link); 2568 } 2569 2570 static void 2571 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2572 { 2573 Objlist_Entry *elm; 2574 2575 elm = NEW(Objlist_Entry); 2576 elm->obj = obj; 2577 STAILQ_INSERT_TAIL(list, elm, link); 2578 } 2579 2580 static void 2581 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2582 { 2583 Objlist_Entry *elm, *listelm; 2584 2585 STAILQ_FOREACH(listelm, list, link) { 2586 if (listelm->obj == listobj) 2587 break; 2588 } 2589 elm = NEW(Objlist_Entry); 2590 elm->obj = obj; 2591 if (listelm != NULL) 2592 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2593 else 2594 STAILQ_INSERT_TAIL(list, elm, link); 2595 } 2596 2597 static void 2598 objlist_remove(Objlist *list, Obj_Entry *obj) 2599 { 2600 Objlist_Entry *elm; 2601 2602 if ((elm = objlist_find(list, obj)) != NULL) { 2603 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2604 free(elm); 2605 } 2606 } 2607 2608 /* 2609 * Relocate dag rooted in the specified object. 2610 * Returns 0 on success, or -1 on failure. 2611 */ 2612 2613 static int 2614 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2615 int flags, RtldLockState *lockstate) 2616 { 2617 Objlist_Entry *elm; 2618 int error; 2619 2620 error = 0; 2621 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2622 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2623 lockstate); 2624 if (error == -1) 2625 break; 2626 } 2627 return (error); 2628 } 2629 2630 /* 2631 * Prepare for, or clean after, relocating an object marked with 2632 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2633 * segments are remapped read-write. After relocations are done, the 2634 * segment's permissions are returned back to the modes specified in 2635 * the phdrs. If any relocation happened, or always for wired 2636 * program, COW is triggered. 2637 */ 2638 static int 2639 reloc_textrel_prot(Obj_Entry *obj, bool before) 2640 { 2641 const Elf_Phdr *ph; 2642 void *base; 2643 size_t l, sz; 2644 int prot; 2645 2646 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2647 l--, ph++) { 2648 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2649 continue; 2650 base = obj->relocbase + trunc_page(ph->p_vaddr); 2651 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2652 trunc_page(ph->p_vaddr); 2653 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2654 if (mprotect(base, sz, prot) == -1) { 2655 _rtld_error("%s: Cannot write-%sable text segment: %s", 2656 obj->path, before ? "en" : "dis", 2657 rtld_strerror(errno)); 2658 return (-1); 2659 } 2660 } 2661 return (0); 2662 } 2663 2664 /* 2665 * Relocate single object. 2666 * Returns 0 on success, or -1 on failure. 2667 */ 2668 static int 2669 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2670 int flags, RtldLockState *lockstate) 2671 { 2672 2673 if (obj->relocated) 2674 return (0); 2675 obj->relocated = true; 2676 if (obj != rtldobj) 2677 dbg("relocating \"%s\"", obj->path); 2678 2679 if (obj->symtab == NULL || obj->strtab == NULL || 2680 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2681 _rtld_error("%s: Shared object has no run-time symbol table", 2682 obj->path); 2683 return (-1); 2684 } 2685 2686 /* There are relocations to the write-protected text segment. */ 2687 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2688 return (-1); 2689 2690 /* Process the non-PLT non-IFUNC relocations. */ 2691 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2692 return (-1); 2693 2694 /* Re-protected the text segment. */ 2695 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2696 return (-1); 2697 2698 /* Set the special PLT or GOT entries. */ 2699 init_pltgot(obj); 2700 2701 /* Process the PLT relocations. */ 2702 if (reloc_plt(obj) == -1) 2703 return (-1); 2704 /* Relocate the jump slots if we are doing immediate binding. */ 2705 if (obj->bind_now || bind_now) 2706 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2707 return (-1); 2708 2709 /* 2710 * Process the non-PLT IFUNC relocations. The relocations are 2711 * processed in two phases, because IFUNC resolvers may 2712 * reference other symbols, which must be readily processed 2713 * before resolvers are called. 2714 */ 2715 if (obj->non_plt_gnu_ifunc && 2716 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2717 return (-1); 2718 2719 if (obj->relro_size > 0) { 2720 if (mprotect(obj->relro_page, obj->relro_size, 2721 PROT_READ) == -1) { 2722 _rtld_error("%s: Cannot enforce relro protection: %s", 2723 obj->path, rtld_strerror(errno)); 2724 return (-1); 2725 } 2726 } 2727 2728 /* 2729 * Set up the magic number and version in the Obj_Entry. These 2730 * were checked in the crt1.o from the original ElfKit, so we 2731 * set them for backward compatibility. 2732 */ 2733 obj->magic = RTLD_MAGIC; 2734 obj->version = RTLD_VERSION; 2735 2736 return (0); 2737 } 2738 2739 /* 2740 * Relocate newly-loaded shared objects. The argument is a pointer to 2741 * the Obj_Entry for the first such object. All objects from the first 2742 * to the end of the list of objects are relocated. Returns 0 on success, 2743 * or -1 on failure. 2744 */ 2745 static int 2746 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2747 int flags, RtldLockState *lockstate) 2748 { 2749 Obj_Entry *obj; 2750 int error; 2751 2752 for (error = 0, obj = first; obj != NULL; 2753 obj = TAILQ_NEXT(obj, next)) { 2754 if (obj->marker) 2755 continue; 2756 error = relocate_object(obj, bind_now, rtldobj, flags, 2757 lockstate); 2758 if (error == -1) 2759 break; 2760 } 2761 return (error); 2762 } 2763 2764 /* 2765 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2766 * referencing STT_GNU_IFUNC symbols is postponed till the other 2767 * relocations are done. The indirect functions specified as 2768 * ifunc are allowed to call other symbols, so we need to have 2769 * objects relocated before asking for resolution from indirects. 2770 * 2771 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2772 * instead of the usual lazy handling of PLT slots. It is 2773 * consistent with how GNU does it. 2774 */ 2775 static int 2776 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2777 RtldLockState *lockstate) 2778 { 2779 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2780 return (-1); 2781 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2782 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2783 return (-1); 2784 return (0); 2785 } 2786 2787 static int 2788 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2789 RtldLockState *lockstate) 2790 { 2791 Obj_Entry *obj; 2792 2793 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2794 if (obj->marker) 2795 continue; 2796 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2797 return (-1); 2798 } 2799 return (0); 2800 } 2801 2802 static int 2803 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2804 RtldLockState *lockstate) 2805 { 2806 Objlist_Entry *elm; 2807 2808 STAILQ_FOREACH(elm, list, link) { 2809 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2810 lockstate) == -1) 2811 return (-1); 2812 } 2813 return (0); 2814 } 2815 2816 /* 2817 * Cleanup procedure. It will be called (by the atexit mechanism) just 2818 * before the process exits. 2819 */ 2820 static void 2821 rtld_exit(void) 2822 { 2823 RtldLockState lockstate; 2824 2825 wlock_acquire(rtld_bind_lock, &lockstate); 2826 dbg("rtld_exit()"); 2827 objlist_call_fini(&list_fini, NULL, &lockstate); 2828 /* No need to remove the items from the list, since we are exiting. */ 2829 if (!libmap_disable) 2830 lm_fini(); 2831 lock_release(rtld_bind_lock, &lockstate); 2832 } 2833 2834 /* 2835 * Iterate over a search path, translate each element, and invoke the 2836 * callback on the result. 2837 */ 2838 static void * 2839 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2840 { 2841 const char *trans; 2842 if (path == NULL) 2843 return (NULL); 2844 2845 path += strspn(path, ":;"); 2846 while (*path != '\0') { 2847 size_t len; 2848 char *res; 2849 2850 len = strcspn(path, ":;"); 2851 trans = lm_findn(NULL, path, len); 2852 if (trans) 2853 res = callback(trans, strlen(trans), arg); 2854 else 2855 res = callback(path, len, arg); 2856 2857 if (res != NULL) 2858 return (res); 2859 2860 path += len; 2861 path += strspn(path, ":;"); 2862 } 2863 2864 return (NULL); 2865 } 2866 2867 struct try_library_args { 2868 const char *name; 2869 size_t namelen; 2870 char *buffer; 2871 size_t buflen; 2872 }; 2873 2874 static void * 2875 try_library_path(const char *dir, size_t dirlen, void *param) 2876 { 2877 struct try_library_args *arg; 2878 2879 arg = param; 2880 if (*dir == '/' || trust) { 2881 char *pathname; 2882 2883 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2884 return (NULL); 2885 2886 pathname = arg->buffer; 2887 strncpy(pathname, dir, dirlen); 2888 pathname[dirlen] = '/'; 2889 strcpy(pathname + dirlen + 1, arg->name); 2890 2891 dbg(" Trying \"%s\"", pathname); 2892 if (access(pathname, F_OK) == 0) { /* We found it */ 2893 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2894 strcpy(pathname, arg->buffer); 2895 return (pathname); 2896 } 2897 } 2898 return (NULL); 2899 } 2900 2901 static char * 2902 search_library_path(const char *name, const char *path) 2903 { 2904 char *p; 2905 struct try_library_args arg; 2906 2907 if (path == NULL) 2908 return NULL; 2909 2910 arg.name = name; 2911 arg.namelen = strlen(name); 2912 arg.buffer = xmalloc(PATH_MAX); 2913 arg.buflen = PATH_MAX; 2914 2915 p = path_enumerate(path, try_library_path, &arg); 2916 2917 free(arg.buffer); 2918 2919 return (p); 2920 } 2921 2922 2923 /* 2924 * Finds the library with the given name using the directory descriptors 2925 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2926 * 2927 * Returns a freshly-opened close-on-exec file descriptor for the library, 2928 * or -1 if the library cannot be found. 2929 */ 2930 static char * 2931 search_library_pathfds(const char *name, const char *path, int *fdp) 2932 { 2933 char *envcopy, *fdstr, *found, *last_token; 2934 size_t len; 2935 int dirfd, fd; 2936 2937 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2938 2939 /* Don't load from user-specified libdirs into setuid binaries. */ 2940 if (!trust) 2941 return (NULL); 2942 2943 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2944 if (path == NULL) 2945 return (NULL); 2946 2947 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2948 if (name[0] == '/') { 2949 dbg("Absolute path (%s) passed to %s", name, __func__); 2950 return (NULL); 2951 } 2952 2953 /* 2954 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2955 * copy of the path, as strtok_r rewrites separator tokens 2956 * with '\0'. 2957 */ 2958 found = NULL; 2959 envcopy = xstrdup(path); 2960 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2961 fdstr = strtok_r(NULL, ":", &last_token)) { 2962 dirfd = parse_libdir(fdstr); 2963 if (dirfd < 0) 2964 break; 2965 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2966 if (fd >= 0) { 2967 *fdp = fd; 2968 len = strlen(fdstr) + strlen(name) + 3; 2969 found = xmalloc(len); 2970 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2971 _rtld_error("error generating '%d/%s'", 2972 dirfd, name); 2973 rtld_die(); 2974 } 2975 dbg("open('%s') => %d", found, fd); 2976 break; 2977 } 2978 } 2979 free(envcopy); 2980 2981 return (found); 2982 } 2983 2984 2985 int 2986 dlclose(void *handle) 2987 { 2988 Obj_Entry *root; 2989 RtldLockState lockstate; 2990 2991 wlock_acquire(rtld_bind_lock, &lockstate); 2992 root = dlcheck(handle); 2993 if (root == NULL) { 2994 lock_release(rtld_bind_lock, &lockstate); 2995 return -1; 2996 } 2997 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2998 root->path); 2999 3000 /* Unreference the object and its dependencies. */ 3001 root->dl_refcount--; 3002 3003 if (root->refcount == 1) { 3004 /* 3005 * The object will be no longer referenced, so we must unload it. 3006 * First, call the fini functions. 3007 */ 3008 objlist_call_fini(&list_fini, root, &lockstate); 3009 3010 unref_dag(root); 3011 3012 /* Finish cleaning up the newly-unreferenced objects. */ 3013 GDB_STATE(RT_DELETE,&root->linkmap); 3014 unload_object(root); 3015 GDB_STATE(RT_CONSISTENT,NULL); 3016 } else 3017 unref_dag(root); 3018 3019 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3020 lock_release(rtld_bind_lock, &lockstate); 3021 return 0; 3022 } 3023 3024 char * 3025 dlerror(void) 3026 { 3027 char *msg = error_message; 3028 error_message = NULL; 3029 return msg; 3030 } 3031 3032 /* 3033 * This function is deprecated and has no effect. 3034 */ 3035 void 3036 dllockinit(void *context, 3037 void *(*lock_create)(void *context), 3038 void (*rlock_acquire)(void *lock), 3039 void (*wlock_acquire)(void *lock), 3040 void (*lock_release)(void *lock), 3041 void (*lock_destroy)(void *lock), 3042 void (*context_destroy)(void *context)) 3043 { 3044 static void *cur_context; 3045 static void (*cur_context_destroy)(void *); 3046 3047 /* Just destroy the context from the previous call, if necessary. */ 3048 if (cur_context_destroy != NULL) 3049 cur_context_destroy(cur_context); 3050 cur_context = context; 3051 cur_context_destroy = context_destroy; 3052 } 3053 3054 void * 3055 dlopen(const char *name, int mode) 3056 { 3057 3058 return (rtld_dlopen(name, -1, mode)); 3059 } 3060 3061 void * 3062 fdlopen(int fd, int mode) 3063 { 3064 3065 return (rtld_dlopen(NULL, fd, mode)); 3066 } 3067 3068 static void * 3069 rtld_dlopen(const char *name, int fd, int mode) 3070 { 3071 RtldLockState lockstate; 3072 int lo_flags; 3073 3074 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3075 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3076 if (ld_tracing != NULL) { 3077 rlock_acquire(rtld_bind_lock, &lockstate); 3078 if (sigsetjmp(lockstate.env, 0) != 0) 3079 lock_upgrade(rtld_bind_lock, &lockstate); 3080 environ = (char **)*get_program_var_addr("environ", &lockstate); 3081 lock_release(rtld_bind_lock, &lockstate); 3082 } 3083 lo_flags = RTLD_LO_DLOPEN; 3084 if (mode & RTLD_NODELETE) 3085 lo_flags |= RTLD_LO_NODELETE; 3086 if (mode & RTLD_NOLOAD) 3087 lo_flags |= RTLD_LO_NOLOAD; 3088 if (ld_tracing != NULL) 3089 lo_flags |= RTLD_LO_TRACE; 3090 3091 return (dlopen_object(name, fd, obj_main, lo_flags, 3092 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3093 } 3094 3095 static void 3096 dlopen_cleanup(Obj_Entry *obj) 3097 { 3098 3099 obj->dl_refcount--; 3100 unref_dag(obj); 3101 if (obj->refcount == 0) 3102 unload_object(obj); 3103 } 3104 3105 static Obj_Entry * 3106 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3107 int mode, RtldLockState *lockstate) 3108 { 3109 Obj_Entry *old_obj_tail; 3110 Obj_Entry *obj; 3111 Objlist initlist; 3112 RtldLockState mlockstate; 3113 int result; 3114 3115 objlist_init(&initlist); 3116 3117 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3118 wlock_acquire(rtld_bind_lock, &mlockstate); 3119 lockstate = &mlockstate; 3120 } 3121 GDB_STATE(RT_ADD,NULL); 3122 3123 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3124 obj = NULL; 3125 if (name == NULL && fd == -1) { 3126 obj = obj_main; 3127 obj->refcount++; 3128 } else { 3129 obj = load_object(name, fd, refobj, lo_flags); 3130 } 3131 3132 if (obj) { 3133 obj->dl_refcount++; 3134 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3135 objlist_push_tail(&list_global, obj); 3136 if (globallist_next(old_obj_tail) != NULL) { 3137 /* We loaded something new. */ 3138 assert(globallist_next(old_obj_tail) == obj); 3139 result = load_needed_objects(obj, 3140 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3141 init_dag(obj); 3142 ref_dag(obj); 3143 if (result != -1) 3144 result = rtld_verify_versions(&obj->dagmembers); 3145 if (result != -1 && ld_tracing) 3146 goto trace; 3147 if (result == -1 || relocate_object_dag(obj, 3148 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3149 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3150 lockstate) == -1) { 3151 dlopen_cleanup(obj); 3152 obj = NULL; 3153 } else if (lo_flags & RTLD_LO_EARLY) { 3154 /* 3155 * Do not call the init functions for early loaded 3156 * filtees. The image is still not initialized enough 3157 * for them to work. 3158 * 3159 * Our object is found by the global object list and 3160 * will be ordered among all init calls done right 3161 * before transferring control to main. 3162 */ 3163 } else { 3164 /* Make list of init functions to call. */ 3165 initlist_add_objects(obj, obj, &initlist); 3166 } 3167 /* 3168 * Process all no_delete or global objects here, given 3169 * them own DAGs to prevent their dependencies from being 3170 * unloaded. This has to be done after we have loaded all 3171 * of the dependencies, so that we do not miss any. 3172 */ 3173 if (obj != NULL) 3174 process_z(obj); 3175 } else { 3176 /* 3177 * Bump the reference counts for objects on this DAG. If 3178 * this is the first dlopen() call for the object that was 3179 * already loaded as a dependency, initialize the dag 3180 * starting at it. 3181 */ 3182 init_dag(obj); 3183 ref_dag(obj); 3184 3185 if ((lo_flags & RTLD_LO_TRACE) != 0) 3186 goto trace; 3187 } 3188 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3189 obj->z_nodelete) && !obj->ref_nodel) { 3190 dbg("obj %s nodelete", obj->path); 3191 ref_dag(obj); 3192 obj->z_nodelete = obj->ref_nodel = true; 3193 } 3194 } 3195 3196 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3197 name); 3198 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3199 3200 if (!(lo_flags & RTLD_LO_EARLY)) { 3201 map_stacks_exec(lockstate); 3202 } 3203 3204 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3205 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3206 lockstate) == -1) { 3207 objlist_clear(&initlist); 3208 dlopen_cleanup(obj); 3209 if (lockstate == &mlockstate) 3210 lock_release(rtld_bind_lock, lockstate); 3211 return (NULL); 3212 } 3213 3214 if (!(lo_flags & RTLD_LO_EARLY)) { 3215 /* Call the init functions. */ 3216 objlist_call_init(&initlist, lockstate); 3217 } 3218 objlist_clear(&initlist); 3219 if (lockstate == &mlockstate) 3220 lock_release(rtld_bind_lock, lockstate); 3221 return obj; 3222 trace: 3223 trace_loaded_objects(obj); 3224 if (lockstate == &mlockstate) 3225 lock_release(rtld_bind_lock, lockstate); 3226 exit(0); 3227 } 3228 3229 static void * 3230 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3231 int flags) 3232 { 3233 DoneList donelist; 3234 const Obj_Entry *obj, *defobj; 3235 const Elf_Sym *def; 3236 SymLook req; 3237 RtldLockState lockstate; 3238 tls_index ti; 3239 void *sym; 3240 int res; 3241 3242 def = NULL; 3243 defobj = NULL; 3244 symlook_init(&req, name); 3245 req.ventry = ve; 3246 req.flags = flags | SYMLOOK_IN_PLT; 3247 req.lockstate = &lockstate; 3248 3249 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3250 rlock_acquire(rtld_bind_lock, &lockstate); 3251 if (sigsetjmp(lockstate.env, 0) != 0) 3252 lock_upgrade(rtld_bind_lock, &lockstate); 3253 if (handle == NULL || handle == RTLD_NEXT || 3254 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3255 3256 if ((obj = obj_from_addr(retaddr)) == NULL) { 3257 _rtld_error("Cannot determine caller's shared object"); 3258 lock_release(rtld_bind_lock, &lockstate); 3259 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3260 return NULL; 3261 } 3262 if (handle == NULL) { /* Just the caller's shared object. */ 3263 res = symlook_obj(&req, obj); 3264 if (res == 0) { 3265 def = req.sym_out; 3266 defobj = req.defobj_out; 3267 } 3268 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3269 handle == RTLD_SELF) { /* ... caller included */ 3270 if (handle == RTLD_NEXT) 3271 obj = globallist_next(obj); 3272 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3273 if (obj->marker) 3274 continue; 3275 res = symlook_obj(&req, obj); 3276 if (res == 0) { 3277 if (def == NULL || 3278 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3279 def = req.sym_out; 3280 defobj = req.defobj_out; 3281 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3282 break; 3283 } 3284 } 3285 } 3286 /* 3287 * Search the dynamic linker itself, and possibly resolve the 3288 * symbol from there. This is how the application links to 3289 * dynamic linker services such as dlopen. 3290 */ 3291 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3292 res = symlook_obj(&req, &obj_rtld); 3293 if (res == 0) { 3294 def = req.sym_out; 3295 defobj = req.defobj_out; 3296 } 3297 } 3298 } else { 3299 assert(handle == RTLD_DEFAULT); 3300 res = symlook_default(&req, obj); 3301 if (res == 0) { 3302 defobj = req.defobj_out; 3303 def = req.sym_out; 3304 } 3305 } 3306 } else { 3307 if ((obj = dlcheck(handle)) == NULL) { 3308 lock_release(rtld_bind_lock, &lockstate); 3309 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3310 return NULL; 3311 } 3312 3313 donelist_init(&donelist); 3314 if (obj->mainprog) { 3315 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3316 res = symlook_global(&req, &donelist); 3317 if (res == 0) { 3318 def = req.sym_out; 3319 defobj = req.defobj_out; 3320 } 3321 /* 3322 * Search the dynamic linker itself, and possibly resolve the 3323 * symbol from there. This is how the application links to 3324 * dynamic linker services such as dlopen. 3325 */ 3326 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3327 res = symlook_obj(&req, &obj_rtld); 3328 if (res == 0) { 3329 def = req.sym_out; 3330 defobj = req.defobj_out; 3331 } 3332 } 3333 } 3334 else { 3335 /* Search the whole DAG rooted at the given object. */ 3336 res = symlook_list(&req, &obj->dagmembers, &donelist); 3337 if (res == 0) { 3338 def = req.sym_out; 3339 defobj = req.defobj_out; 3340 } 3341 } 3342 } 3343 3344 if (def != NULL) { 3345 lock_release(rtld_bind_lock, &lockstate); 3346 3347 /* 3348 * The value required by the caller is derived from the value 3349 * of the symbol. this is simply the relocated value of the 3350 * symbol. 3351 */ 3352 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3353 sym = make_function_pointer(def, defobj); 3354 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3355 sym = rtld_resolve_ifunc(defobj, def); 3356 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3357 ti.ti_module = defobj->tlsindex; 3358 ti.ti_offset = def->st_value; 3359 sym = __tls_get_addr(&ti); 3360 } else 3361 sym = defobj->relocbase + def->st_value; 3362 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3363 return (sym); 3364 } 3365 3366 _rtld_error("Undefined symbol \"%s\"", name); 3367 lock_release(rtld_bind_lock, &lockstate); 3368 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3369 return NULL; 3370 } 3371 3372 void * 3373 dlsym(void *handle, const char *name) 3374 { 3375 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3376 SYMLOOK_DLSYM); 3377 } 3378 3379 dlfunc_t 3380 dlfunc(void *handle, const char *name) 3381 { 3382 union { 3383 void *d; 3384 dlfunc_t f; 3385 } rv; 3386 3387 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3388 SYMLOOK_DLSYM); 3389 return (rv.f); 3390 } 3391 3392 void * 3393 dlvsym(void *handle, const char *name, const char *version) 3394 { 3395 Ver_Entry ventry; 3396 3397 ventry.name = version; 3398 ventry.file = NULL; 3399 ventry.hash = elf_hash(version); 3400 ventry.flags= 0; 3401 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3402 SYMLOOK_DLSYM); 3403 } 3404 3405 int 3406 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3407 { 3408 const Obj_Entry *obj; 3409 RtldLockState lockstate; 3410 3411 rlock_acquire(rtld_bind_lock, &lockstate); 3412 obj = obj_from_addr(addr); 3413 if (obj == NULL) { 3414 _rtld_error("No shared object contains address"); 3415 lock_release(rtld_bind_lock, &lockstate); 3416 return (0); 3417 } 3418 rtld_fill_dl_phdr_info(obj, phdr_info); 3419 lock_release(rtld_bind_lock, &lockstate); 3420 return (1); 3421 } 3422 3423 int 3424 dladdr(const void *addr, Dl_info *info) 3425 { 3426 const Obj_Entry *obj; 3427 const Elf_Sym *def; 3428 void *symbol_addr; 3429 unsigned long symoffset; 3430 RtldLockState lockstate; 3431 3432 rlock_acquire(rtld_bind_lock, &lockstate); 3433 obj = obj_from_addr(addr); 3434 if (obj == NULL) { 3435 _rtld_error("No shared object contains address"); 3436 lock_release(rtld_bind_lock, &lockstate); 3437 return 0; 3438 } 3439 info->dli_fname = obj->path; 3440 info->dli_fbase = obj->mapbase; 3441 info->dli_saddr = (void *)0; 3442 info->dli_sname = NULL; 3443 3444 /* 3445 * Walk the symbol list looking for the symbol whose address is 3446 * closest to the address sent in. 3447 */ 3448 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3449 def = obj->symtab + symoffset; 3450 3451 /* 3452 * For skip the symbol if st_shndx is either SHN_UNDEF or 3453 * SHN_COMMON. 3454 */ 3455 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3456 continue; 3457 3458 /* 3459 * If the symbol is greater than the specified address, or if it 3460 * is further away from addr than the current nearest symbol, 3461 * then reject it. 3462 */ 3463 symbol_addr = obj->relocbase + def->st_value; 3464 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3465 continue; 3466 3467 /* Update our idea of the nearest symbol. */ 3468 info->dli_sname = obj->strtab + def->st_name; 3469 info->dli_saddr = symbol_addr; 3470 3471 /* Exact match? */ 3472 if (info->dli_saddr == addr) 3473 break; 3474 } 3475 lock_release(rtld_bind_lock, &lockstate); 3476 return 1; 3477 } 3478 3479 int 3480 dlinfo(void *handle, int request, void *p) 3481 { 3482 const Obj_Entry *obj; 3483 RtldLockState lockstate; 3484 int error; 3485 3486 rlock_acquire(rtld_bind_lock, &lockstate); 3487 3488 if (handle == NULL || handle == RTLD_SELF) { 3489 void *retaddr; 3490 3491 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3492 if ((obj = obj_from_addr(retaddr)) == NULL) 3493 _rtld_error("Cannot determine caller's shared object"); 3494 } else 3495 obj = dlcheck(handle); 3496 3497 if (obj == NULL) { 3498 lock_release(rtld_bind_lock, &lockstate); 3499 return (-1); 3500 } 3501 3502 error = 0; 3503 switch (request) { 3504 case RTLD_DI_LINKMAP: 3505 *((struct link_map const **)p) = &obj->linkmap; 3506 break; 3507 case RTLD_DI_ORIGIN: 3508 error = rtld_dirname(obj->path, p); 3509 break; 3510 3511 case RTLD_DI_SERINFOSIZE: 3512 case RTLD_DI_SERINFO: 3513 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3514 break; 3515 3516 default: 3517 _rtld_error("Invalid request %d passed to dlinfo()", request); 3518 error = -1; 3519 } 3520 3521 lock_release(rtld_bind_lock, &lockstate); 3522 3523 return (error); 3524 } 3525 3526 static void 3527 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3528 { 3529 3530 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3531 phdr_info->dlpi_name = obj->path; 3532 phdr_info->dlpi_phdr = obj->phdr; 3533 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3534 phdr_info->dlpi_tls_modid = obj->tlsindex; 3535 phdr_info->dlpi_tls_data = obj->tlsinit; 3536 phdr_info->dlpi_adds = obj_loads; 3537 phdr_info->dlpi_subs = obj_loads - obj_count; 3538 } 3539 3540 int 3541 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3542 { 3543 struct dl_phdr_info phdr_info; 3544 Obj_Entry *obj, marker; 3545 RtldLockState bind_lockstate, phdr_lockstate; 3546 int error; 3547 3548 bzero(&marker, sizeof(marker)); 3549 marker.marker = true; 3550 error = 0; 3551 3552 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3553 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3554 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3555 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3556 rtld_fill_dl_phdr_info(obj, &phdr_info); 3557 lock_release(rtld_bind_lock, &bind_lockstate); 3558 3559 error = callback(&phdr_info, sizeof phdr_info, param); 3560 3561 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3562 obj = globallist_next(&marker); 3563 TAILQ_REMOVE(&obj_list, &marker, next); 3564 if (error != 0) { 3565 lock_release(rtld_bind_lock, &bind_lockstate); 3566 lock_release(rtld_phdr_lock, &phdr_lockstate); 3567 return (error); 3568 } 3569 } 3570 3571 if (error == 0) { 3572 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3573 lock_release(rtld_bind_lock, &bind_lockstate); 3574 error = callback(&phdr_info, sizeof(phdr_info), param); 3575 } 3576 lock_release(rtld_phdr_lock, &phdr_lockstate); 3577 return (error); 3578 } 3579 3580 static void * 3581 fill_search_info(const char *dir, size_t dirlen, void *param) 3582 { 3583 struct fill_search_info_args *arg; 3584 3585 arg = param; 3586 3587 if (arg->request == RTLD_DI_SERINFOSIZE) { 3588 arg->serinfo->dls_cnt ++; 3589 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3590 } else { 3591 struct dl_serpath *s_entry; 3592 3593 s_entry = arg->serpath; 3594 s_entry->dls_name = arg->strspace; 3595 s_entry->dls_flags = arg->flags; 3596 3597 strncpy(arg->strspace, dir, dirlen); 3598 arg->strspace[dirlen] = '\0'; 3599 3600 arg->strspace += dirlen + 1; 3601 arg->serpath++; 3602 } 3603 3604 return (NULL); 3605 } 3606 3607 static int 3608 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3609 { 3610 struct dl_serinfo _info; 3611 struct fill_search_info_args args; 3612 3613 args.request = RTLD_DI_SERINFOSIZE; 3614 args.serinfo = &_info; 3615 3616 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3617 _info.dls_cnt = 0; 3618 3619 path_enumerate(obj->rpath, fill_search_info, &args); 3620 path_enumerate(ld_library_path, fill_search_info, &args); 3621 path_enumerate(obj->runpath, fill_search_info, &args); 3622 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3623 if (!obj->z_nodeflib) 3624 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3625 3626 3627 if (request == RTLD_DI_SERINFOSIZE) { 3628 info->dls_size = _info.dls_size; 3629 info->dls_cnt = _info.dls_cnt; 3630 return (0); 3631 } 3632 3633 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3634 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3635 return (-1); 3636 } 3637 3638 args.request = RTLD_DI_SERINFO; 3639 args.serinfo = info; 3640 args.serpath = &info->dls_serpath[0]; 3641 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3642 3643 args.flags = LA_SER_RUNPATH; 3644 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3645 return (-1); 3646 3647 args.flags = LA_SER_LIBPATH; 3648 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3649 return (-1); 3650 3651 args.flags = LA_SER_RUNPATH; 3652 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3653 return (-1); 3654 3655 args.flags = LA_SER_CONFIG; 3656 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3657 != NULL) 3658 return (-1); 3659 3660 args.flags = LA_SER_DEFAULT; 3661 if (!obj->z_nodeflib && 3662 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3663 return (-1); 3664 return (0); 3665 } 3666 3667 static int 3668 rtld_dirname(const char *path, char *bname) 3669 { 3670 const char *endp; 3671 3672 /* Empty or NULL string gets treated as "." */ 3673 if (path == NULL || *path == '\0') { 3674 bname[0] = '.'; 3675 bname[1] = '\0'; 3676 return (0); 3677 } 3678 3679 /* Strip trailing slashes */ 3680 endp = path + strlen(path) - 1; 3681 while (endp > path && *endp == '/') 3682 endp--; 3683 3684 /* Find the start of the dir */ 3685 while (endp > path && *endp != '/') 3686 endp--; 3687 3688 /* Either the dir is "/" or there are no slashes */ 3689 if (endp == path) { 3690 bname[0] = *endp == '/' ? '/' : '.'; 3691 bname[1] = '\0'; 3692 return (0); 3693 } else { 3694 do { 3695 endp--; 3696 } while (endp > path && *endp == '/'); 3697 } 3698 3699 if (endp - path + 2 > PATH_MAX) 3700 { 3701 _rtld_error("Filename is too long: %s", path); 3702 return(-1); 3703 } 3704 3705 strncpy(bname, path, endp - path + 1); 3706 bname[endp - path + 1] = '\0'; 3707 return (0); 3708 } 3709 3710 static int 3711 rtld_dirname_abs(const char *path, char *base) 3712 { 3713 char *last; 3714 3715 if (realpath(path, base) == NULL) 3716 return (-1); 3717 dbg("%s -> %s", path, base); 3718 last = strrchr(base, '/'); 3719 if (last == NULL) 3720 return (-1); 3721 if (last != base) 3722 *last = '\0'; 3723 return (0); 3724 } 3725 3726 static void 3727 linkmap_add(Obj_Entry *obj) 3728 { 3729 struct link_map *l = &obj->linkmap; 3730 struct link_map *prev; 3731 3732 obj->linkmap.l_name = obj->path; 3733 obj->linkmap.l_addr = obj->mapbase; 3734 obj->linkmap.l_ld = obj->dynamic; 3735 #ifdef __mips__ 3736 /* GDB needs load offset on MIPS to use the symbols */ 3737 obj->linkmap.l_offs = obj->relocbase; 3738 #endif 3739 3740 if (r_debug.r_map == NULL) { 3741 r_debug.r_map = l; 3742 return; 3743 } 3744 3745 /* 3746 * Scan to the end of the list, but not past the entry for the 3747 * dynamic linker, which we want to keep at the very end. 3748 */ 3749 for (prev = r_debug.r_map; 3750 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3751 prev = prev->l_next) 3752 ; 3753 3754 /* Link in the new entry. */ 3755 l->l_prev = prev; 3756 l->l_next = prev->l_next; 3757 if (l->l_next != NULL) 3758 l->l_next->l_prev = l; 3759 prev->l_next = l; 3760 } 3761 3762 static void 3763 linkmap_delete(Obj_Entry *obj) 3764 { 3765 struct link_map *l = &obj->linkmap; 3766 3767 if (l->l_prev == NULL) { 3768 if ((r_debug.r_map = l->l_next) != NULL) 3769 l->l_next->l_prev = NULL; 3770 return; 3771 } 3772 3773 if ((l->l_prev->l_next = l->l_next) != NULL) 3774 l->l_next->l_prev = l->l_prev; 3775 } 3776 3777 /* 3778 * Function for the debugger to set a breakpoint on to gain control. 3779 * 3780 * The two parameters allow the debugger to easily find and determine 3781 * what the runtime loader is doing and to whom it is doing it. 3782 * 3783 * When the loadhook trap is hit (r_debug_state, set at program 3784 * initialization), the arguments can be found on the stack: 3785 * 3786 * +8 struct link_map *m 3787 * +4 struct r_debug *rd 3788 * +0 RetAddr 3789 */ 3790 void 3791 r_debug_state(struct r_debug* rd, struct link_map *m) 3792 { 3793 /* 3794 * The following is a hack to force the compiler to emit calls to 3795 * this function, even when optimizing. If the function is empty, 3796 * the compiler is not obliged to emit any code for calls to it, 3797 * even when marked __noinline. However, gdb depends on those 3798 * calls being made. 3799 */ 3800 __compiler_membar(); 3801 } 3802 3803 /* 3804 * A function called after init routines have completed. This can be used to 3805 * break before a program's entry routine is called, and can be used when 3806 * main is not available in the symbol table. 3807 */ 3808 void 3809 _r_debug_postinit(struct link_map *m) 3810 { 3811 3812 /* See r_debug_state(). */ 3813 __compiler_membar(); 3814 } 3815 3816 /* 3817 * Get address of the pointer variable in the main program. 3818 * Prefer non-weak symbol over the weak one. 3819 */ 3820 static const void ** 3821 get_program_var_addr(const char *name, RtldLockState *lockstate) 3822 { 3823 SymLook req; 3824 DoneList donelist; 3825 3826 symlook_init(&req, name); 3827 req.lockstate = lockstate; 3828 donelist_init(&donelist); 3829 if (symlook_global(&req, &donelist) != 0) 3830 return (NULL); 3831 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3832 return ((const void **)make_function_pointer(req.sym_out, 3833 req.defobj_out)); 3834 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3835 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3836 else 3837 return ((const void **)(req.defobj_out->relocbase + 3838 req.sym_out->st_value)); 3839 } 3840 3841 /* 3842 * Set a pointer variable in the main program to the given value. This 3843 * is used to set key variables such as "environ" before any of the 3844 * init functions are called. 3845 */ 3846 static void 3847 set_program_var(const char *name, const void *value) 3848 { 3849 const void **addr; 3850 3851 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3852 dbg("\"%s\": *%p <-- %p", name, addr, value); 3853 *addr = value; 3854 } 3855 } 3856 3857 /* 3858 * Search the global objects, including dependencies and main object, 3859 * for the given symbol. 3860 */ 3861 static int 3862 symlook_global(SymLook *req, DoneList *donelist) 3863 { 3864 SymLook req1; 3865 const Objlist_Entry *elm; 3866 int res; 3867 3868 symlook_init_from_req(&req1, req); 3869 3870 /* Search all objects loaded at program start up. */ 3871 if (req->defobj_out == NULL || 3872 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3873 res = symlook_list(&req1, &list_main, donelist); 3874 if (res == 0 && (req->defobj_out == NULL || 3875 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3876 req->sym_out = req1.sym_out; 3877 req->defobj_out = req1.defobj_out; 3878 assert(req->defobj_out != NULL); 3879 } 3880 } 3881 3882 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3883 STAILQ_FOREACH(elm, &list_global, link) { 3884 if (req->defobj_out != NULL && 3885 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3886 break; 3887 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3888 if (res == 0 && (req->defobj_out == NULL || 3889 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3890 req->sym_out = req1.sym_out; 3891 req->defobj_out = req1.defobj_out; 3892 assert(req->defobj_out != NULL); 3893 } 3894 } 3895 3896 return (req->sym_out != NULL ? 0 : ESRCH); 3897 } 3898 3899 /* 3900 * Given a symbol name in a referencing object, find the corresponding 3901 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3902 * no definition was found. Returns a pointer to the Obj_Entry of the 3903 * defining object via the reference parameter DEFOBJ_OUT. 3904 */ 3905 static int 3906 symlook_default(SymLook *req, const Obj_Entry *refobj) 3907 { 3908 DoneList donelist; 3909 const Objlist_Entry *elm; 3910 SymLook req1; 3911 int res; 3912 3913 donelist_init(&donelist); 3914 symlook_init_from_req(&req1, req); 3915 3916 /* Look first in the referencing object if linked symbolically. */ 3917 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3918 res = symlook_obj(&req1, refobj); 3919 if (res == 0) { 3920 req->sym_out = req1.sym_out; 3921 req->defobj_out = req1.defobj_out; 3922 assert(req->defobj_out != NULL); 3923 } 3924 } 3925 3926 symlook_global(req, &donelist); 3927 3928 /* Search all dlopened DAGs containing the referencing object. */ 3929 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3930 if (req->sym_out != NULL && 3931 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3932 break; 3933 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3934 if (res == 0 && (req->sym_out == NULL || 3935 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3936 req->sym_out = req1.sym_out; 3937 req->defobj_out = req1.defobj_out; 3938 assert(req->defobj_out != NULL); 3939 } 3940 } 3941 3942 /* 3943 * Search the dynamic linker itself, and possibly resolve the 3944 * symbol from there. This is how the application links to 3945 * dynamic linker services such as dlopen. 3946 */ 3947 if (req->sym_out == NULL || 3948 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3949 res = symlook_obj(&req1, &obj_rtld); 3950 if (res == 0) { 3951 req->sym_out = req1.sym_out; 3952 req->defobj_out = req1.defobj_out; 3953 assert(req->defobj_out != NULL); 3954 } 3955 } 3956 3957 return (req->sym_out != NULL ? 0 : ESRCH); 3958 } 3959 3960 static int 3961 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3962 { 3963 const Elf_Sym *def; 3964 const Obj_Entry *defobj; 3965 const Objlist_Entry *elm; 3966 SymLook req1; 3967 int res; 3968 3969 def = NULL; 3970 defobj = NULL; 3971 STAILQ_FOREACH(elm, objlist, link) { 3972 if (donelist_check(dlp, elm->obj)) 3973 continue; 3974 symlook_init_from_req(&req1, req); 3975 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3976 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3977 def = req1.sym_out; 3978 defobj = req1.defobj_out; 3979 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3980 break; 3981 } 3982 } 3983 } 3984 if (def != NULL) { 3985 req->sym_out = def; 3986 req->defobj_out = defobj; 3987 return (0); 3988 } 3989 return (ESRCH); 3990 } 3991 3992 /* 3993 * Search the chain of DAGS cointed to by the given Needed_Entry 3994 * for a symbol of the given name. Each DAG is scanned completely 3995 * before advancing to the next one. Returns a pointer to the symbol, 3996 * or NULL if no definition was found. 3997 */ 3998 static int 3999 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4000 { 4001 const Elf_Sym *def; 4002 const Needed_Entry *n; 4003 const Obj_Entry *defobj; 4004 SymLook req1; 4005 int res; 4006 4007 def = NULL; 4008 defobj = NULL; 4009 symlook_init_from_req(&req1, req); 4010 for (n = needed; n != NULL; n = n->next) { 4011 if (n->obj == NULL || 4012 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4013 continue; 4014 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4015 def = req1.sym_out; 4016 defobj = req1.defobj_out; 4017 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4018 break; 4019 } 4020 } 4021 if (def != NULL) { 4022 req->sym_out = def; 4023 req->defobj_out = defobj; 4024 return (0); 4025 } 4026 return (ESRCH); 4027 } 4028 4029 /* 4030 * Search the symbol table of a single shared object for a symbol of 4031 * the given name and version, if requested. Returns a pointer to the 4032 * symbol, or NULL if no definition was found. If the object is 4033 * filter, return filtered symbol from filtee. 4034 * 4035 * The symbol's hash value is passed in for efficiency reasons; that 4036 * eliminates many recomputations of the hash value. 4037 */ 4038 int 4039 symlook_obj(SymLook *req, const Obj_Entry *obj) 4040 { 4041 DoneList donelist; 4042 SymLook req1; 4043 int flags, res, mres; 4044 4045 /* 4046 * If there is at least one valid hash at this point, we prefer to 4047 * use the faster GNU version if available. 4048 */ 4049 if (obj->valid_hash_gnu) 4050 mres = symlook_obj1_gnu(req, obj); 4051 else if (obj->valid_hash_sysv) 4052 mres = symlook_obj1_sysv(req, obj); 4053 else 4054 return (EINVAL); 4055 4056 if (mres == 0) { 4057 if (obj->needed_filtees != NULL) { 4058 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4059 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4060 donelist_init(&donelist); 4061 symlook_init_from_req(&req1, req); 4062 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4063 if (res == 0) { 4064 req->sym_out = req1.sym_out; 4065 req->defobj_out = req1.defobj_out; 4066 } 4067 return (res); 4068 } 4069 if (obj->needed_aux_filtees != NULL) { 4070 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4071 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4072 donelist_init(&donelist); 4073 symlook_init_from_req(&req1, req); 4074 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4075 if (res == 0) { 4076 req->sym_out = req1.sym_out; 4077 req->defobj_out = req1.defobj_out; 4078 return (res); 4079 } 4080 } 4081 } 4082 return (mres); 4083 } 4084 4085 /* Symbol match routine common to both hash functions */ 4086 static bool 4087 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4088 const unsigned long symnum) 4089 { 4090 Elf_Versym verndx; 4091 const Elf_Sym *symp; 4092 const char *strp; 4093 4094 symp = obj->symtab + symnum; 4095 strp = obj->strtab + symp->st_name; 4096 4097 switch (ELF_ST_TYPE(symp->st_info)) { 4098 case STT_FUNC: 4099 case STT_NOTYPE: 4100 case STT_OBJECT: 4101 case STT_COMMON: 4102 case STT_GNU_IFUNC: 4103 if (symp->st_value == 0) 4104 return (false); 4105 /* fallthrough */ 4106 case STT_TLS: 4107 if (symp->st_shndx != SHN_UNDEF) 4108 break; 4109 #ifndef __mips__ 4110 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4111 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4112 break; 4113 /* fallthrough */ 4114 #endif 4115 default: 4116 return (false); 4117 } 4118 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4119 return (false); 4120 4121 if (req->ventry == NULL) { 4122 if (obj->versyms != NULL) { 4123 verndx = VER_NDX(obj->versyms[symnum]); 4124 if (verndx > obj->vernum) { 4125 _rtld_error( 4126 "%s: symbol %s references wrong version %d", 4127 obj->path, obj->strtab + symnum, verndx); 4128 return (false); 4129 } 4130 /* 4131 * If we are not called from dlsym (i.e. this 4132 * is a normal relocation from unversioned 4133 * binary), accept the symbol immediately if 4134 * it happens to have first version after this 4135 * shared object became versioned. Otherwise, 4136 * if symbol is versioned and not hidden, 4137 * remember it. If it is the only symbol with 4138 * this name exported by the shared object, it 4139 * will be returned as a match by the calling 4140 * function. If symbol is global (verndx < 2) 4141 * accept it unconditionally. 4142 */ 4143 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4144 verndx == VER_NDX_GIVEN) { 4145 result->sym_out = symp; 4146 return (true); 4147 } 4148 else if (verndx >= VER_NDX_GIVEN) { 4149 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4150 == 0) { 4151 if (result->vsymp == NULL) 4152 result->vsymp = symp; 4153 result->vcount++; 4154 } 4155 return (false); 4156 } 4157 } 4158 result->sym_out = symp; 4159 return (true); 4160 } 4161 if (obj->versyms == NULL) { 4162 if (object_match_name(obj, req->ventry->name)) { 4163 _rtld_error("%s: object %s should provide version %s " 4164 "for symbol %s", obj_rtld.path, obj->path, 4165 req->ventry->name, obj->strtab + symnum); 4166 return (false); 4167 } 4168 } else { 4169 verndx = VER_NDX(obj->versyms[symnum]); 4170 if (verndx > obj->vernum) { 4171 _rtld_error("%s: symbol %s references wrong version %d", 4172 obj->path, obj->strtab + symnum, verndx); 4173 return (false); 4174 } 4175 if (obj->vertab[verndx].hash != req->ventry->hash || 4176 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4177 /* 4178 * Version does not match. Look if this is a 4179 * global symbol and if it is not hidden. If 4180 * global symbol (verndx < 2) is available, 4181 * use it. Do not return symbol if we are 4182 * called by dlvsym, because dlvsym looks for 4183 * a specific version and default one is not 4184 * what dlvsym wants. 4185 */ 4186 if ((req->flags & SYMLOOK_DLSYM) || 4187 (verndx >= VER_NDX_GIVEN) || 4188 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4189 return (false); 4190 } 4191 } 4192 result->sym_out = symp; 4193 return (true); 4194 } 4195 4196 /* 4197 * Search for symbol using SysV hash function. 4198 * obj->buckets is known not to be NULL at this point; the test for this was 4199 * performed with the obj->valid_hash_sysv assignment. 4200 */ 4201 static int 4202 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4203 { 4204 unsigned long symnum; 4205 Sym_Match_Result matchres; 4206 4207 matchres.sym_out = NULL; 4208 matchres.vsymp = NULL; 4209 matchres.vcount = 0; 4210 4211 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4212 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4213 if (symnum >= obj->nchains) 4214 return (ESRCH); /* Bad object */ 4215 4216 if (matched_symbol(req, obj, &matchres, symnum)) { 4217 req->sym_out = matchres.sym_out; 4218 req->defobj_out = obj; 4219 return (0); 4220 } 4221 } 4222 if (matchres.vcount == 1) { 4223 req->sym_out = matchres.vsymp; 4224 req->defobj_out = obj; 4225 return (0); 4226 } 4227 return (ESRCH); 4228 } 4229 4230 /* Search for symbol using GNU hash function */ 4231 static int 4232 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4233 { 4234 Elf_Addr bloom_word; 4235 const Elf32_Word *hashval; 4236 Elf32_Word bucket; 4237 Sym_Match_Result matchres; 4238 unsigned int h1, h2; 4239 unsigned long symnum; 4240 4241 matchres.sym_out = NULL; 4242 matchres.vsymp = NULL; 4243 matchres.vcount = 0; 4244 4245 /* Pick right bitmask word from Bloom filter array */ 4246 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4247 obj->maskwords_bm_gnu]; 4248 4249 /* Calculate modulus word size of gnu hash and its derivative */ 4250 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4251 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4252 4253 /* Filter out the "definitely not in set" queries */ 4254 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4255 return (ESRCH); 4256 4257 /* Locate hash chain and corresponding value element*/ 4258 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4259 if (bucket == 0) 4260 return (ESRCH); 4261 hashval = &obj->chain_zero_gnu[bucket]; 4262 do { 4263 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4264 symnum = hashval - obj->chain_zero_gnu; 4265 if (matched_symbol(req, obj, &matchres, symnum)) { 4266 req->sym_out = matchres.sym_out; 4267 req->defobj_out = obj; 4268 return (0); 4269 } 4270 } 4271 } while ((*hashval++ & 1) == 0); 4272 if (matchres.vcount == 1) { 4273 req->sym_out = matchres.vsymp; 4274 req->defobj_out = obj; 4275 return (0); 4276 } 4277 return (ESRCH); 4278 } 4279 4280 static void 4281 trace_loaded_objects(Obj_Entry *obj) 4282 { 4283 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4284 int c; 4285 4286 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4287 main_local = ""; 4288 4289 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4290 fmt1 = "\t%o => %p (%x)\n"; 4291 4292 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4293 fmt2 = "\t%o (%x)\n"; 4294 4295 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4296 4297 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4298 Needed_Entry *needed; 4299 char *name, *path; 4300 bool is_lib; 4301 4302 if (obj->marker) 4303 continue; 4304 if (list_containers && obj->needed != NULL) 4305 rtld_printf("%s:\n", obj->path); 4306 for (needed = obj->needed; needed; needed = needed->next) { 4307 if (needed->obj != NULL) { 4308 if (needed->obj->traced && !list_containers) 4309 continue; 4310 needed->obj->traced = true; 4311 path = needed->obj->path; 4312 } else 4313 path = "not found"; 4314 4315 name = (char *)obj->strtab + needed->name; 4316 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4317 4318 fmt = is_lib ? fmt1 : fmt2; 4319 while ((c = *fmt++) != '\0') { 4320 switch (c) { 4321 default: 4322 rtld_putchar(c); 4323 continue; 4324 case '\\': 4325 switch (c = *fmt) { 4326 case '\0': 4327 continue; 4328 case 'n': 4329 rtld_putchar('\n'); 4330 break; 4331 case 't': 4332 rtld_putchar('\t'); 4333 break; 4334 } 4335 break; 4336 case '%': 4337 switch (c = *fmt) { 4338 case '\0': 4339 continue; 4340 case '%': 4341 default: 4342 rtld_putchar(c); 4343 break; 4344 case 'A': 4345 rtld_putstr(main_local); 4346 break; 4347 case 'a': 4348 rtld_putstr(obj_main->path); 4349 break; 4350 case 'o': 4351 rtld_putstr(name); 4352 break; 4353 #if 0 4354 case 'm': 4355 rtld_printf("%d", sodp->sod_major); 4356 break; 4357 case 'n': 4358 rtld_printf("%d", sodp->sod_minor); 4359 break; 4360 #endif 4361 case 'p': 4362 rtld_putstr(path); 4363 break; 4364 case 'x': 4365 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4366 0); 4367 break; 4368 } 4369 break; 4370 } 4371 ++fmt; 4372 } 4373 } 4374 } 4375 } 4376 4377 /* 4378 * Unload a dlopened object and its dependencies from memory and from 4379 * our data structures. It is assumed that the DAG rooted in the 4380 * object has already been unreferenced, and that the object has a 4381 * reference count of 0. 4382 */ 4383 static void 4384 unload_object(Obj_Entry *root) 4385 { 4386 Obj_Entry *obj, *obj1; 4387 4388 assert(root->refcount == 0); 4389 4390 /* 4391 * Pass over the DAG removing unreferenced objects from 4392 * appropriate lists. 4393 */ 4394 unlink_object(root); 4395 4396 /* Unmap all objects that are no longer referenced. */ 4397 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4398 if (obj->marker || obj->refcount != 0) 4399 continue; 4400 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4401 obj->mapsize, 0, obj->path); 4402 dbg("unloading \"%s\"", obj->path); 4403 unload_filtees(root); 4404 munmap(obj->mapbase, obj->mapsize); 4405 linkmap_delete(obj); 4406 TAILQ_REMOVE(&obj_list, obj, next); 4407 obj_count--; 4408 obj_free(obj); 4409 } 4410 } 4411 4412 static void 4413 unlink_object(Obj_Entry *root) 4414 { 4415 Objlist_Entry *elm; 4416 4417 if (root->refcount == 0) { 4418 /* Remove the object from the RTLD_GLOBAL list. */ 4419 objlist_remove(&list_global, root); 4420 4421 /* Remove the object from all objects' DAG lists. */ 4422 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4423 objlist_remove(&elm->obj->dldags, root); 4424 if (elm->obj != root) 4425 unlink_object(elm->obj); 4426 } 4427 } 4428 } 4429 4430 static void 4431 ref_dag(Obj_Entry *root) 4432 { 4433 Objlist_Entry *elm; 4434 4435 assert(root->dag_inited); 4436 STAILQ_FOREACH(elm, &root->dagmembers, link) 4437 elm->obj->refcount++; 4438 } 4439 4440 static void 4441 unref_dag(Obj_Entry *root) 4442 { 4443 Objlist_Entry *elm; 4444 4445 assert(root->dag_inited); 4446 STAILQ_FOREACH(elm, &root->dagmembers, link) 4447 elm->obj->refcount--; 4448 } 4449 4450 /* 4451 * Common code for MD __tls_get_addr(). 4452 */ 4453 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4454 static void * 4455 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4456 { 4457 Elf_Addr *newdtv, *dtv; 4458 RtldLockState lockstate; 4459 int to_copy; 4460 4461 dtv = *dtvp; 4462 /* Check dtv generation in case new modules have arrived */ 4463 if (dtv[0] != tls_dtv_generation) { 4464 wlock_acquire(rtld_bind_lock, &lockstate); 4465 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4466 to_copy = dtv[1]; 4467 if (to_copy > tls_max_index) 4468 to_copy = tls_max_index; 4469 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4470 newdtv[0] = tls_dtv_generation; 4471 newdtv[1] = tls_max_index; 4472 free(dtv); 4473 lock_release(rtld_bind_lock, &lockstate); 4474 dtv = *dtvp = newdtv; 4475 } 4476 4477 /* Dynamically allocate module TLS if necessary */ 4478 if (dtv[index + 1] == 0) { 4479 /* Signal safe, wlock will block out signals. */ 4480 wlock_acquire(rtld_bind_lock, &lockstate); 4481 if (!dtv[index + 1]) 4482 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4483 lock_release(rtld_bind_lock, &lockstate); 4484 } 4485 return ((void *)(dtv[index + 1] + offset)); 4486 } 4487 4488 void * 4489 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4490 { 4491 Elf_Addr *dtv; 4492 4493 dtv = *dtvp; 4494 /* Check dtv generation in case new modules have arrived */ 4495 if (__predict_true(dtv[0] == tls_dtv_generation && 4496 dtv[index + 1] != 0)) 4497 return ((void *)(dtv[index + 1] + offset)); 4498 return (tls_get_addr_slow(dtvp, index, offset)); 4499 } 4500 4501 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4502 defined(__powerpc__) || defined(__riscv__) 4503 4504 /* 4505 * Allocate Static TLS using the Variant I method. 4506 */ 4507 void * 4508 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4509 { 4510 Obj_Entry *obj; 4511 char *tcb; 4512 Elf_Addr **tls; 4513 Elf_Addr *dtv; 4514 Elf_Addr addr; 4515 int i; 4516 4517 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4518 return (oldtcb); 4519 4520 assert(tcbsize >= TLS_TCB_SIZE); 4521 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4522 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4523 4524 if (oldtcb != NULL) { 4525 memcpy(tls, oldtcb, tls_static_space); 4526 free(oldtcb); 4527 4528 /* Adjust the DTV. */ 4529 dtv = tls[0]; 4530 for (i = 0; i < dtv[1]; i++) { 4531 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4532 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4533 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4534 } 4535 } 4536 } else { 4537 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4538 tls[0] = dtv; 4539 dtv[0] = tls_dtv_generation; 4540 dtv[1] = tls_max_index; 4541 4542 for (obj = globallist_curr(objs); obj != NULL; 4543 obj = globallist_next(obj)) { 4544 if (obj->tlsoffset > 0) { 4545 addr = (Elf_Addr)tls + obj->tlsoffset; 4546 if (obj->tlsinitsize > 0) 4547 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4548 if (obj->tlssize > obj->tlsinitsize) 4549 memset((void*) (addr + obj->tlsinitsize), 0, 4550 obj->tlssize - obj->tlsinitsize); 4551 dtv[obj->tlsindex + 1] = addr; 4552 } 4553 } 4554 } 4555 4556 return (tcb); 4557 } 4558 4559 void 4560 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4561 { 4562 Elf_Addr *dtv; 4563 Elf_Addr tlsstart, tlsend; 4564 int dtvsize, i; 4565 4566 assert(tcbsize >= TLS_TCB_SIZE); 4567 4568 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4569 tlsend = tlsstart + tls_static_space; 4570 4571 dtv = *(Elf_Addr **)tlsstart; 4572 dtvsize = dtv[1]; 4573 for (i = 0; i < dtvsize; i++) { 4574 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4575 free((void*)dtv[i+2]); 4576 } 4577 } 4578 free(dtv); 4579 free(tcb); 4580 } 4581 4582 #endif 4583 4584 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4585 4586 /* 4587 * Allocate Static TLS using the Variant II method. 4588 */ 4589 void * 4590 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4591 { 4592 Obj_Entry *obj; 4593 size_t size, ralign; 4594 char *tls; 4595 Elf_Addr *dtv, *olddtv; 4596 Elf_Addr segbase, oldsegbase, addr; 4597 int i; 4598 4599 ralign = tcbalign; 4600 if (tls_static_max_align > ralign) 4601 ralign = tls_static_max_align; 4602 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4603 4604 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4605 tls = malloc_aligned(size, ralign); 4606 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4607 4608 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4609 ((Elf_Addr*)segbase)[0] = segbase; 4610 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4611 4612 dtv[0] = tls_dtv_generation; 4613 dtv[1] = tls_max_index; 4614 4615 if (oldtls) { 4616 /* 4617 * Copy the static TLS block over whole. 4618 */ 4619 oldsegbase = (Elf_Addr) oldtls; 4620 memcpy((void *)(segbase - tls_static_space), 4621 (const void *)(oldsegbase - tls_static_space), 4622 tls_static_space); 4623 4624 /* 4625 * If any dynamic TLS blocks have been created tls_get_addr(), 4626 * move them over. 4627 */ 4628 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4629 for (i = 0; i < olddtv[1]; i++) { 4630 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4631 dtv[i+2] = olddtv[i+2]; 4632 olddtv[i+2] = 0; 4633 } 4634 } 4635 4636 /* 4637 * We assume that this block was the one we created with 4638 * allocate_initial_tls(). 4639 */ 4640 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4641 } else { 4642 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4643 if (obj->marker || obj->tlsoffset == 0) 4644 continue; 4645 addr = segbase - obj->tlsoffset; 4646 memset((void*) (addr + obj->tlsinitsize), 4647 0, obj->tlssize - obj->tlsinitsize); 4648 if (obj->tlsinit) 4649 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4650 dtv[obj->tlsindex + 1] = addr; 4651 } 4652 } 4653 4654 return (void*) segbase; 4655 } 4656 4657 void 4658 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4659 { 4660 Elf_Addr* dtv; 4661 size_t size, ralign; 4662 int dtvsize, i; 4663 Elf_Addr tlsstart, tlsend; 4664 4665 /* 4666 * Figure out the size of the initial TLS block so that we can 4667 * find stuff which ___tls_get_addr() allocated dynamically. 4668 */ 4669 ralign = tcbalign; 4670 if (tls_static_max_align > ralign) 4671 ralign = tls_static_max_align; 4672 size = round(tls_static_space, ralign); 4673 4674 dtv = ((Elf_Addr**)tls)[1]; 4675 dtvsize = dtv[1]; 4676 tlsend = (Elf_Addr) tls; 4677 tlsstart = tlsend - size; 4678 for (i = 0; i < dtvsize; i++) { 4679 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4680 free_aligned((void *)dtv[i + 2]); 4681 } 4682 } 4683 4684 free_aligned((void *)tlsstart); 4685 free((void*) dtv); 4686 } 4687 4688 #endif 4689 4690 /* 4691 * Allocate TLS block for module with given index. 4692 */ 4693 void * 4694 allocate_module_tls(int index) 4695 { 4696 Obj_Entry* obj; 4697 char* p; 4698 4699 TAILQ_FOREACH(obj, &obj_list, next) { 4700 if (obj->marker) 4701 continue; 4702 if (obj->tlsindex == index) 4703 break; 4704 } 4705 if (!obj) { 4706 _rtld_error("Can't find module with TLS index %d", index); 4707 rtld_die(); 4708 } 4709 4710 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4711 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4712 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4713 4714 return p; 4715 } 4716 4717 bool 4718 allocate_tls_offset(Obj_Entry *obj) 4719 { 4720 size_t off; 4721 4722 if (obj->tls_done) 4723 return true; 4724 4725 if (obj->tlssize == 0) { 4726 obj->tls_done = true; 4727 return true; 4728 } 4729 4730 if (tls_last_offset == 0) 4731 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4732 else 4733 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4734 obj->tlssize, obj->tlsalign); 4735 4736 /* 4737 * If we have already fixed the size of the static TLS block, we 4738 * must stay within that size. When allocating the static TLS, we 4739 * leave a small amount of space spare to be used for dynamically 4740 * loading modules which use static TLS. 4741 */ 4742 if (tls_static_space != 0) { 4743 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4744 return false; 4745 } else if (obj->tlsalign > tls_static_max_align) { 4746 tls_static_max_align = obj->tlsalign; 4747 } 4748 4749 tls_last_offset = obj->tlsoffset = off; 4750 tls_last_size = obj->tlssize; 4751 obj->tls_done = true; 4752 4753 return true; 4754 } 4755 4756 void 4757 free_tls_offset(Obj_Entry *obj) 4758 { 4759 4760 /* 4761 * If we were the last thing to allocate out of the static TLS 4762 * block, we give our space back to the 'allocator'. This is a 4763 * simplistic workaround to allow libGL.so.1 to be loaded and 4764 * unloaded multiple times. 4765 */ 4766 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4767 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4768 tls_last_offset -= obj->tlssize; 4769 tls_last_size = 0; 4770 } 4771 } 4772 4773 void * 4774 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4775 { 4776 void *ret; 4777 RtldLockState lockstate; 4778 4779 wlock_acquire(rtld_bind_lock, &lockstate); 4780 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4781 tcbsize, tcbalign); 4782 lock_release(rtld_bind_lock, &lockstate); 4783 return (ret); 4784 } 4785 4786 void 4787 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4788 { 4789 RtldLockState lockstate; 4790 4791 wlock_acquire(rtld_bind_lock, &lockstate); 4792 free_tls(tcb, tcbsize, tcbalign); 4793 lock_release(rtld_bind_lock, &lockstate); 4794 } 4795 4796 static void 4797 object_add_name(Obj_Entry *obj, const char *name) 4798 { 4799 Name_Entry *entry; 4800 size_t len; 4801 4802 len = strlen(name); 4803 entry = malloc(sizeof(Name_Entry) + len); 4804 4805 if (entry != NULL) { 4806 strcpy(entry->name, name); 4807 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4808 } 4809 } 4810 4811 static int 4812 object_match_name(const Obj_Entry *obj, const char *name) 4813 { 4814 Name_Entry *entry; 4815 4816 STAILQ_FOREACH(entry, &obj->names, link) { 4817 if (strcmp(name, entry->name) == 0) 4818 return (1); 4819 } 4820 return (0); 4821 } 4822 4823 static Obj_Entry * 4824 locate_dependency(const Obj_Entry *obj, const char *name) 4825 { 4826 const Objlist_Entry *entry; 4827 const Needed_Entry *needed; 4828 4829 STAILQ_FOREACH(entry, &list_main, link) { 4830 if (object_match_name(entry->obj, name)) 4831 return entry->obj; 4832 } 4833 4834 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4835 if (strcmp(obj->strtab + needed->name, name) == 0 || 4836 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4837 /* 4838 * If there is DT_NEEDED for the name we are looking for, 4839 * we are all set. Note that object might not be found if 4840 * dependency was not loaded yet, so the function can 4841 * return NULL here. This is expected and handled 4842 * properly by the caller. 4843 */ 4844 return (needed->obj); 4845 } 4846 } 4847 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4848 obj->path, name); 4849 rtld_die(); 4850 } 4851 4852 static int 4853 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4854 const Elf_Vernaux *vna) 4855 { 4856 const Elf_Verdef *vd; 4857 const char *vername; 4858 4859 vername = refobj->strtab + vna->vna_name; 4860 vd = depobj->verdef; 4861 if (vd == NULL) { 4862 _rtld_error("%s: version %s required by %s not defined", 4863 depobj->path, vername, refobj->path); 4864 return (-1); 4865 } 4866 for (;;) { 4867 if (vd->vd_version != VER_DEF_CURRENT) { 4868 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4869 depobj->path, vd->vd_version); 4870 return (-1); 4871 } 4872 if (vna->vna_hash == vd->vd_hash) { 4873 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4874 ((char *)vd + vd->vd_aux); 4875 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4876 return (0); 4877 } 4878 if (vd->vd_next == 0) 4879 break; 4880 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4881 } 4882 if (vna->vna_flags & VER_FLG_WEAK) 4883 return (0); 4884 _rtld_error("%s: version %s required by %s not found", 4885 depobj->path, vername, refobj->path); 4886 return (-1); 4887 } 4888 4889 static int 4890 rtld_verify_object_versions(Obj_Entry *obj) 4891 { 4892 const Elf_Verneed *vn; 4893 const Elf_Verdef *vd; 4894 const Elf_Verdaux *vda; 4895 const Elf_Vernaux *vna; 4896 const Obj_Entry *depobj; 4897 int maxvernum, vernum; 4898 4899 if (obj->ver_checked) 4900 return (0); 4901 obj->ver_checked = true; 4902 4903 maxvernum = 0; 4904 /* 4905 * Walk over defined and required version records and figure out 4906 * max index used by any of them. Do very basic sanity checking 4907 * while there. 4908 */ 4909 vn = obj->verneed; 4910 while (vn != NULL) { 4911 if (vn->vn_version != VER_NEED_CURRENT) { 4912 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4913 obj->path, vn->vn_version); 4914 return (-1); 4915 } 4916 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4917 for (;;) { 4918 vernum = VER_NEED_IDX(vna->vna_other); 4919 if (vernum > maxvernum) 4920 maxvernum = vernum; 4921 if (vna->vna_next == 0) 4922 break; 4923 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4924 } 4925 if (vn->vn_next == 0) 4926 break; 4927 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4928 } 4929 4930 vd = obj->verdef; 4931 while (vd != NULL) { 4932 if (vd->vd_version != VER_DEF_CURRENT) { 4933 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4934 obj->path, vd->vd_version); 4935 return (-1); 4936 } 4937 vernum = VER_DEF_IDX(vd->vd_ndx); 4938 if (vernum > maxvernum) 4939 maxvernum = vernum; 4940 if (vd->vd_next == 0) 4941 break; 4942 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4943 } 4944 4945 if (maxvernum == 0) 4946 return (0); 4947 4948 /* 4949 * Store version information in array indexable by version index. 4950 * Verify that object version requirements are satisfied along the 4951 * way. 4952 */ 4953 obj->vernum = maxvernum + 1; 4954 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4955 4956 vd = obj->verdef; 4957 while (vd != NULL) { 4958 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4959 vernum = VER_DEF_IDX(vd->vd_ndx); 4960 assert(vernum <= maxvernum); 4961 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4962 obj->vertab[vernum].hash = vd->vd_hash; 4963 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4964 obj->vertab[vernum].file = NULL; 4965 obj->vertab[vernum].flags = 0; 4966 } 4967 if (vd->vd_next == 0) 4968 break; 4969 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4970 } 4971 4972 vn = obj->verneed; 4973 while (vn != NULL) { 4974 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4975 if (depobj == NULL) 4976 return (-1); 4977 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4978 for (;;) { 4979 if (check_object_provided_version(obj, depobj, vna)) 4980 return (-1); 4981 vernum = VER_NEED_IDX(vna->vna_other); 4982 assert(vernum <= maxvernum); 4983 obj->vertab[vernum].hash = vna->vna_hash; 4984 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4985 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4986 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4987 VER_INFO_HIDDEN : 0; 4988 if (vna->vna_next == 0) 4989 break; 4990 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4991 } 4992 if (vn->vn_next == 0) 4993 break; 4994 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4995 } 4996 return 0; 4997 } 4998 4999 static int 5000 rtld_verify_versions(const Objlist *objlist) 5001 { 5002 Objlist_Entry *entry; 5003 int rc; 5004 5005 rc = 0; 5006 STAILQ_FOREACH(entry, objlist, link) { 5007 /* 5008 * Skip dummy objects or objects that have their version requirements 5009 * already checked. 5010 */ 5011 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5012 continue; 5013 if (rtld_verify_object_versions(entry->obj) == -1) { 5014 rc = -1; 5015 if (ld_tracing == NULL) 5016 break; 5017 } 5018 } 5019 if (rc == 0 || ld_tracing != NULL) 5020 rc = rtld_verify_object_versions(&obj_rtld); 5021 return rc; 5022 } 5023 5024 const Ver_Entry * 5025 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5026 { 5027 Elf_Versym vernum; 5028 5029 if (obj->vertab) { 5030 vernum = VER_NDX(obj->versyms[symnum]); 5031 if (vernum >= obj->vernum) { 5032 _rtld_error("%s: symbol %s has wrong verneed value %d", 5033 obj->path, obj->strtab + symnum, vernum); 5034 } else if (obj->vertab[vernum].hash != 0) { 5035 return &obj->vertab[vernum]; 5036 } 5037 } 5038 return NULL; 5039 } 5040 5041 int 5042 _rtld_get_stack_prot(void) 5043 { 5044 5045 return (stack_prot); 5046 } 5047 5048 int 5049 _rtld_is_dlopened(void *arg) 5050 { 5051 Obj_Entry *obj; 5052 RtldLockState lockstate; 5053 int res; 5054 5055 rlock_acquire(rtld_bind_lock, &lockstate); 5056 obj = dlcheck(arg); 5057 if (obj == NULL) 5058 obj = obj_from_addr(arg); 5059 if (obj == NULL) { 5060 _rtld_error("No shared object contains address"); 5061 lock_release(rtld_bind_lock, &lockstate); 5062 return (-1); 5063 } 5064 res = obj->dlopened ? 1 : 0; 5065 lock_release(rtld_bind_lock, &lockstate); 5066 return (res); 5067 } 5068 5069 static void 5070 map_stacks_exec(RtldLockState *lockstate) 5071 { 5072 void (*thr_map_stacks_exec)(void); 5073 5074 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5075 return; 5076 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5077 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5078 if (thr_map_stacks_exec != NULL) { 5079 stack_prot |= PROT_EXEC; 5080 thr_map_stacks_exec(); 5081 } 5082 } 5083 5084 void 5085 symlook_init(SymLook *dst, const char *name) 5086 { 5087 5088 bzero(dst, sizeof(*dst)); 5089 dst->name = name; 5090 dst->hash = elf_hash(name); 5091 dst->hash_gnu = gnu_hash(name); 5092 } 5093 5094 static void 5095 symlook_init_from_req(SymLook *dst, const SymLook *src) 5096 { 5097 5098 dst->name = src->name; 5099 dst->hash = src->hash; 5100 dst->hash_gnu = src->hash_gnu; 5101 dst->ventry = src->ventry; 5102 dst->flags = src->flags; 5103 dst->defobj_out = NULL; 5104 dst->sym_out = NULL; 5105 dst->lockstate = src->lockstate; 5106 } 5107 5108 5109 /* 5110 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5111 */ 5112 static int 5113 parse_libdir(const char *str) 5114 { 5115 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5116 const char *orig; 5117 int fd; 5118 char c; 5119 5120 orig = str; 5121 fd = 0; 5122 for (c = *str; c != '\0'; c = *++str) { 5123 if (c < '0' || c > '9') 5124 return (-1); 5125 5126 fd *= RADIX; 5127 fd += c - '0'; 5128 } 5129 5130 /* Make sure we actually parsed something. */ 5131 if (str == orig) { 5132 _rtld_error("failed to parse directory FD from '%s'", str); 5133 return (-1); 5134 } 5135 return (fd); 5136 } 5137 5138 /* 5139 * Overrides for libc_pic-provided functions. 5140 */ 5141 5142 int 5143 __getosreldate(void) 5144 { 5145 size_t len; 5146 int oid[2]; 5147 int error, osrel; 5148 5149 if (osreldate != 0) 5150 return (osreldate); 5151 5152 oid[0] = CTL_KERN; 5153 oid[1] = KERN_OSRELDATE; 5154 osrel = 0; 5155 len = sizeof(osrel); 5156 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5157 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5158 osreldate = osrel; 5159 return (osreldate); 5160 } 5161 5162 void 5163 exit(int status) 5164 { 5165 5166 _exit(status); 5167 } 5168 5169 void (*__cleanup)(void); 5170 int __isthreaded = 0; 5171 int _thread_autoinit_dummy_decl = 1; 5172 5173 /* 5174 * No unresolved symbols for rtld. 5175 */ 5176 void 5177 __pthread_cxa_finalize(struct dl_phdr_info *a) 5178 { 5179 } 5180 5181 void 5182 __stack_chk_fail(void) 5183 { 5184 5185 _rtld_error("stack overflow detected; terminated"); 5186 rtld_die(); 5187 } 5188 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5189 5190 void 5191 __chk_fail(void) 5192 { 5193 5194 _rtld_error("buffer overflow detected; terminated"); 5195 rtld_die(); 5196 } 5197 5198 const char * 5199 rtld_strerror(int errnum) 5200 { 5201 5202 if (errnum < 0 || errnum >= sys_nerr) 5203 return ("Unknown error"); 5204 return (sys_errlist[errnum]); 5205 } 5206