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 hold_object(Obj_Entry *); 91 static void unhold_object(Obj_Entry *); 92 static void init_dag(Obj_Entry *); 93 static void init_marker(Obj_Entry *); 94 static void init_pagesizes(Elf_Auxinfo **aux_info); 95 static void init_rtld(caddr_t, Elf_Auxinfo **); 96 static void initlist_add_neededs(Needed_Entry *, Objlist *); 97 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 98 static void linkmap_add(Obj_Entry *); 99 static void linkmap_delete(Obj_Entry *); 100 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 101 static void unload_filtees(Obj_Entry *); 102 static int load_needed_objects(Obj_Entry *, int); 103 static int load_preload_objects(void); 104 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 105 static void map_stacks_exec(RtldLockState *); 106 static int obj_enforce_relro(Obj_Entry *); 107 static Obj_Entry *obj_from_addr(const void *); 108 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 109 static void objlist_call_init(Objlist *, RtldLockState *); 110 static void objlist_clear(Objlist *); 111 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 112 static void objlist_init(Objlist *); 113 static void objlist_push_head(Objlist *, Obj_Entry *); 114 static void objlist_push_tail(Objlist *, Obj_Entry *); 115 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 116 static void objlist_remove(Objlist *, Obj_Entry *); 117 static int parse_libdir(const char *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static void release_object(Obj_Entry *); 120 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 121 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 122 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 123 int flags, RtldLockState *lockstate); 124 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 125 RtldLockState *); 126 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 127 int flags, RtldLockState *lockstate); 128 static int rtld_dirname(const char *, char *); 129 static int rtld_dirname_abs(const char *, char *); 130 static void *rtld_dlopen(const char *name, int fd, int mode); 131 static void rtld_exit(void); 132 static char *search_library_path(const char *, const char *); 133 static char *search_library_pathfds(const char *, const char *, int *); 134 static const void **get_program_var_addr(const char *, RtldLockState *); 135 static void set_program_var(const char *, const void *); 136 static int symlook_default(SymLook *, const Obj_Entry *refobj); 137 static int symlook_global(SymLook *, DoneList *); 138 static void symlook_init_from_req(SymLook *, const SymLook *); 139 static int symlook_list(SymLook *, const Objlist *, DoneList *); 140 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 141 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 142 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 143 static void trace_loaded_objects(Obj_Entry *); 144 static void unlink_object(Obj_Entry *); 145 static void unload_object(Obj_Entry *); 146 static void unref_dag(Obj_Entry *); 147 static void ref_dag(Obj_Entry *); 148 static char *origin_subst_one(Obj_Entry *, char *, const char *, 149 const char *, bool); 150 static char *origin_subst(Obj_Entry *, char *); 151 static bool obj_resolve_origin(Obj_Entry *obj); 152 static void preinit_main(void); 153 static int rtld_verify_versions(const Objlist *); 154 static int rtld_verify_object_versions(Obj_Entry *); 155 static void object_add_name(Obj_Entry *, const char *); 156 static int object_match_name(const Obj_Entry *, const char *); 157 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 158 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 159 struct dl_phdr_info *phdr_info); 160 static uint32_t gnu_hash(const char *); 161 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 162 const unsigned long); 163 164 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 165 void _r_debug_postinit(struct link_map *) __noinline __exported; 166 167 int __sys_openat(int, const char *, int, ...); 168 169 /* 170 * Data declarations. 171 */ 172 static char *error_message; /* Message for dlerror(), or NULL */ 173 struct r_debug r_debug __exported; /* for GDB; */ 174 static bool libmap_disable; /* Disable libmap */ 175 static bool ld_loadfltr; /* Immediate filters processing */ 176 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 177 static bool trust; /* False for setuid and setgid programs */ 178 static bool dangerous_ld_env; /* True if environment variables have been 179 used to affect the libraries loaded */ 180 static char *ld_bind_now; /* Environment variable for immediate binding */ 181 static char *ld_debug; /* Environment variable for debugging */ 182 static char *ld_library_path; /* Environment variable for search path */ 183 static char *ld_library_dirs; /* Environment variable for library descriptors */ 184 static char *ld_preload; /* Environment variable for libraries to 185 load first */ 186 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 187 static char *ld_tracing; /* Called from ldd to print libs */ 188 static char *ld_utrace; /* Use utrace() to log events. */ 189 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 190 static Obj_Entry *obj_main; /* The main program shared object */ 191 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 192 static unsigned int obj_count; /* Number of objects in obj_list */ 193 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 194 195 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 196 STAILQ_HEAD_INITIALIZER(list_global); 197 static Objlist list_main = /* Objects loaded at program startup */ 198 STAILQ_HEAD_INITIALIZER(list_main); 199 static Objlist list_fini = /* Objects needing fini() calls */ 200 STAILQ_HEAD_INITIALIZER(list_fini); 201 202 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 203 204 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 205 206 extern Elf_Dyn _DYNAMIC; 207 #pragma weak _DYNAMIC 208 209 int dlclose(void *) __exported; 210 char *dlerror(void) __exported; 211 void *dlopen(const char *, int) __exported; 212 void *fdlopen(int, int) __exported; 213 void *dlsym(void *, const char *) __exported; 214 dlfunc_t dlfunc(void *, const char *) __exported; 215 void *dlvsym(void *, const char *, const char *) __exported; 216 int dladdr(const void *, Dl_info *) __exported; 217 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 218 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 219 int dlinfo(void *, int , void *) __exported; 220 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 221 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 222 int _rtld_get_stack_prot(void) __exported; 223 int _rtld_is_dlopened(void *) __exported; 224 void _rtld_error(const char *, ...) __exported; 225 226 int npagesizes, osreldate; 227 size_t *pagesizes; 228 229 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 230 231 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 232 static int max_stack_flags; 233 234 /* 235 * Global declarations normally provided by crt1. The dynamic linker is 236 * not built with crt1, so we have to provide them ourselves. 237 */ 238 char *__progname; 239 char **environ; 240 241 /* 242 * Used to pass argc, argv to init functions. 243 */ 244 int main_argc; 245 char **main_argv; 246 247 /* 248 * Globals to control TLS allocation. 249 */ 250 size_t tls_last_offset; /* Static TLS offset of last module */ 251 size_t tls_last_size; /* Static TLS size of last module */ 252 size_t tls_static_space; /* Static TLS space allocated */ 253 size_t tls_static_max_align; 254 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 255 int tls_max_index = 1; /* Largest module index allocated */ 256 257 bool ld_library_path_rpath = false; 258 259 /* 260 * Globals for path names, and such 261 */ 262 char *ld_elf_hints_default = _PATH_ELF_HINTS; 263 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 264 char *ld_path_rtld = _PATH_RTLD; 265 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 266 char *ld_env_prefix = LD_; 267 268 /* 269 * Fill in a DoneList with an allocation large enough to hold all of 270 * the currently-loaded objects. Keep this as a macro since it calls 271 * alloca and we want that to occur within the scope of the caller. 272 */ 273 #define donelist_init(dlp) \ 274 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 275 assert((dlp)->objs != NULL), \ 276 (dlp)->num_alloc = obj_count, \ 277 (dlp)->num_used = 0) 278 279 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 280 if (ld_utrace != NULL) \ 281 ld_utrace_log(e, h, mb, ms, r, n); \ 282 } while (0) 283 284 static void 285 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 286 int refcnt, const char *name) 287 { 288 struct utrace_rtld ut; 289 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 290 291 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 292 ut.event = event; 293 ut.handle = handle; 294 ut.mapbase = mapbase; 295 ut.mapsize = mapsize; 296 ut.refcnt = refcnt; 297 bzero(ut.name, sizeof(ut.name)); 298 if (name) 299 strlcpy(ut.name, name, sizeof(ut.name)); 300 utrace(&ut, sizeof(ut)); 301 } 302 303 #ifdef RTLD_VARIANT_ENV_NAMES 304 /* 305 * construct the env variable based on the type of binary that's 306 * running. 307 */ 308 static inline const char * 309 _LD(const char *var) 310 { 311 static char buffer[128]; 312 313 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 314 strlcat(buffer, var, sizeof(buffer)); 315 return (buffer); 316 } 317 #else 318 #define _LD(x) LD_ x 319 #endif 320 321 /* 322 * Main entry point for dynamic linking. The first argument is the 323 * stack pointer. The stack is expected to be laid out as described 324 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 325 * Specifically, the stack pointer points to a word containing 326 * ARGC. Following that in the stack is a null-terminated sequence 327 * of pointers to argument strings. Then comes a null-terminated 328 * sequence of pointers to environment strings. Finally, there is a 329 * sequence of "auxiliary vector" entries. 330 * 331 * The second argument points to a place to store the dynamic linker's 332 * exit procedure pointer and the third to a place to store the main 333 * program's object. 334 * 335 * The return value is the main program's entry point. 336 */ 337 func_ptr_type 338 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 339 { 340 Elf_Auxinfo *aux_info[AT_COUNT]; 341 int i; 342 int argc; 343 char **argv; 344 char **env; 345 Elf_Auxinfo *aux; 346 Elf_Auxinfo *auxp; 347 const char *argv0; 348 Objlist_Entry *entry; 349 Obj_Entry *obj; 350 Obj_Entry *preload_tail; 351 Obj_Entry *last_interposer; 352 Objlist initlist; 353 RtldLockState lockstate; 354 char *library_path_rpath; 355 int mib[2]; 356 size_t len; 357 358 /* 359 * On entry, the dynamic linker itself has not been relocated yet. 360 * Be very careful not to reference any global data until after 361 * init_rtld has returned. It is OK to reference file-scope statics 362 * and string constants, and to call static and global functions. 363 */ 364 365 /* Find the auxiliary vector on the stack. */ 366 argc = *sp++; 367 argv = (char **) sp; 368 sp += argc + 1; /* Skip over arguments and NULL terminator */ 369 env = (char **) sp; 370 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 371 ; 372 aux = (Elf_Auxinfo *) sp; 373 374 /* Digest the auxiliary vector. */ 375 for (i = 0; i < AT_COUNT; i++) 376 aux_info[i] = NULL; 377 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 378 if (auxp->a_type < AT_COUNT) 379 aux_info[auxp->a_type] = auxp; 380 } 381 382 /* Initialize and relocate ourselves. */ 383 assert(aux_info[AT_BASE] != NULL); 384 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 385 386 __progname = obj_rtld.path; 387 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 388 environ = env; 389 main_argc = argc; 390 main_argv = argv; 391 392 if (aux_info[AT_CANARY] != NULL && 393 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 394 i = aux_info[AT_CANARYLEN]->a_un.a_val; 395 if (i > sizeof(__stack_chk_guard)) 396 i = sizeof(__stack_chk_guard); 397 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 398 } else { 399 mib[0] = CTL_KERN; 400 mib[1] = KERN_ARND; 401 402 len = sizeof(__stack_chk_guard); 403 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 404 len != sizeof(__stack_chk_guard)) { 405 /* If sysctl was unsuccessful, use the "terminator canary". */ 406 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 407 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 408 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 409 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 410 } 411 } 412 413 trust = !issetugid(); 414 415 md_abi_variant_hook(aux_info); 416 417 ld_bind_now = getenv(_LD("BIND_NOW")); 418 /* 419 * If the process is tainted, then we un-set the dangerous environment 420 * variables. The process will be marked as tainted until setuid(2) 421 * is called. If any child process calls setuid(2) we do not want any 422 * future processes to honor the potentially un-safe variables. 423 */ 424 if (!trust) { 425 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 426 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 427 unsetenv(_LD("LIBMAP_DISABLE")) || 428 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 429 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 430 _rtld_error("environment corrupt; aborting"); 431 rtld_die(); 432 } 433 } 434 ld_debug = getenv(_LD("DEBUG")); 435 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 436 libmap_override = getenv(_LD("LIBMAP")); 437 ld_library_path = getenv(_LD("LIBRARY_PATH")); 438 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 439 ld_preload = getenv(_LD("PRELOAD")); 440 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 441 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 442 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 443 if (library_path_rpath != NULL) { 444 if (library_path_rpath[0] == 'y' || 445 library_path_rpath[0] == 'Y' || 446 library_path_rpath[0] == '1') 447 ld_library_path_rpath = true; 448 else 449 ld_library_path_rpath = false; 450 } 451 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 452 (ld_library_path != NULL) || (ld_preload != NULL) || 453 (ld_elf_hints_path != NULL) || ld_loadfltr; 454 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 455 ld_utrace = getenv(_LD("UTRACE")); 456 457 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 458 ld_elf_hints_path = ld_elf_hints_default; 459 460 if (ld_debug != NULL && *ld_debug != '\0') 461 debug = 1; 462 dbg("%s is initialized, base address = %p", __progname, 463 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 464 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 465 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 466 467 dbg("initializing thread locks"); 468 lockdflt_init(); 469 470 /* 471 * Load the main program, or process its program header if it is 472 * already loaded. 473 */ 474 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 475 int fd = aux_info[AT_EXECFD]->a_un.a_val; 476 dbg("loading main program"); 477 obj_main = map_object(fd, argv0, NULL); 478 close(fd); 479 if (obj_main == NULL) 480 rtld_die(); 481 max_stack_flags = obj->stack_flags; 482 } else { /* Main program already loaded. */ 483 const Elf_Phdr *phdr; 484 int phnum; 485 caddr_t entry; 486 487 dbg("processing main program's program header"); 488 assert(aux_info[AT_PHDR] != NULL); 489 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 490 assert(aux_info[AT_PHNUM] != NULL); 491 phnum = aux_info[AT_PHNUM]->a_un.a_val; 492 assert(aux_info[AT_PHENT] != NULL); 493 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 494 assert(aux_info[AT_ENTRY] != NULL); 495 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 496 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 497 rtld_die(); 498 } 499 500 if (aux_info[AT_EXECPATH] != NULL) { 501 char *kexecpath; 502 char buf[MAXPATHLEN]; 503 504 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 505 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 506 if (kexecpath[0] == '/') 507 obj_main->path = kexecpath; 508 else if (getcwd(buf, sizeof(buf)) == NULL || 509 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 510 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 511 obj_main->path = xstrdup(argv0); 512 else 513 obj_main->path = xstrdup(buf); 514 } else { 515 dbg("No AT_EXECPATH"); 516 obj_main->path = xstrdup(argv0); 517 } 518 dbg("obj_main path %s", obj_main->path); 519 obj_main->mainprog = true; 520 521 if (aux_info[AT_STACKPROT] != NULL && 522 aux_info[AT_STACKPROT]->a_un.a_val != 0) 523 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 524 525 #ifndef COMPAT_32BIT 526 /* 527 * Get the actual dynamic linker pathname from the executable if 528 * possible. (It should always be possible.) That ensures that 529 * gdb will find the right dynamic linker even if a non-standard 530 * one is being used. 531 */ 532 if (obj_main->interp != NULL && 533 strcmp(obj_main->interp, obj_rtld.path) != 0) { 534 free(obj_rtld.path); 535 obj_rtld.path = xstrdup(obj_main->interp); 536 __progname = obj_rtld.path; 537 } 538 #endif 539 540 digest_dynamic(obj_main, 0); 541 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 542 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 543 obj_main->dynsymcount); 544 545 linkmap_add(obj_main); 546 linkmap_add(&obj_rtld); 547 548 /* Link the main program into the list of objects. */ 549 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 550 obj_count++; 551 obj_loads++; 552 553 /* Initialize a fake symbol for resolving undefined weak references. */ 554 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 555 sym_zero.st_shndx = SHN_UNDEF; 556 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 557 558 if (!libmap_disable) 559 libmap_disable = (bool)lm_init(libmap_override); 560 561 dbg("loading LD_PRELOAD libraries"); 562 if (load_preload_objects() == -1) 563 rtld_die(); 564 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 565 566 dbg("loading needed objects"); 567 if (load_needed_objects(obj_main, 0) == -1) 568 rtld_die(); 569 570 /* Make a list of all objects loaded at startup. */ 571 last_interposer = obj_main; 572 TAILQ_FOREACH(obj, &obj_list, next) { 573 if (obj->marker) 574 continue; 575 if (obj->z_interpose && obj != obj_main) { 576 objlist_put_after(&list_main, last_interposer, obj); 577 last_interposer = obj; 578 } else { 579 objlist_push_tail(&list_main, obj); 580 } 581 obj->refcount++; 582 } 583 584 dbg("checking for required versions"); 585 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 586 rtld_die(); 587 588 if (ld_tracing) { /* We're done */ 589 trace_loaded_objects(obj_main); 590 exit(0); 591 } 592 593 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 594 dump_relocations(obj_main); 595 exit (0); 596 } 597 598 /* 599 * Processing tls relocations requires having the tls offsets 600 * initialized. Prepare offsets before starting initial 601 * relocation processing. 602 */ 603 dbg("initializing initial thread local storage offsets"); 604 STAILQ_FOREACH(entry, &list_main, link) { 605 /* 606 * Allocate all the initial objects out of the static TLS 607 * block even if they didn't ask for it. 608 */ 609 allocate_tls_offset(entry->obj); 610 } 611 612 if (relocate_objects(obj_main, 613 ld_bind_now != NULL && *ld_bind_now != '\0', 614 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 615 rtld_die(); 616 617 dbg("doing copy relocations"); 618 if (do_copy_relocations(obj_main) == -1) 619 rtld_die(); 620 621 dbg("enforcing main obj relro"); 622 if (obj_enforce_relro(obj_main) == -1) 623 rtld_die(); 624 625 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 626 dump_relocations(obj_main); 627 exit (0); 628 } 629 630 /* 631 * Setup TLS for main thread. This must be done after the 632 * relocations are processed, since tls initialization section 633 * might be the subject for relocations. 634 */ 635 dbg("initializing initial thread local storage"); 636 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 637 638 dbg("initializing key program variables"); 639 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 640 set_program_var("environ", env); 641 set_program_var("__elf_aux_vector", aux); 642 643 /* Make a list of init functions to call. */ 644 objlist_init(&initlist); 645 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 646 preload_tail, &initlist); 647 648 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 649 650 map_stacks_exec(NULL); 651 ifunc_init(aux); 652 653 dbg("resolving ifuncs"); 654 if (resolve_objects_ifunc(obj_main, 655 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 656 NULL) == -1) 657 rtld_die(); 658 659 if (!obj_main->crt_no_init) { 660 /* 661 * Make sure we don't call the main program's init and fini 662 * functions for binaries linked with old crt1 which calls 663 * _init itself. 664 */ 665 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 666 obj_main->preinit_array = obj_main->init_array = 667 obj_main->fini_array = (Elf_Addr)NULL; 668 } 669 670 wlock_acquire(rtld_bind_lock, &lockstate); 671 if (obj_main->crt_no_init) 672 preinit_main(); 673 objlist_call_init(&initlist, &lockstate); 674 _r_debug_postinit(&obj_main->linkmap); 675 objlist_clear(&initlist); 676 dbg("loading filtees"); 677 TAILQ_FOREACH(obj, &obj_list, next) { 678 if (obj->marker) 679 continue; 680 if (ld_loadfltr || obj->z_loadfltr) 681 load_filtees(obj, 0, &lockstate); 682 } 683 lock_release(rtld_bind_lock, &lockstate); 684 685 dbg("transferring control to program entry point = %p", obj_main->entry); 686 687 /* Return the exit procedure and the program entry point. */ 688 *exit_proc = rtld_exit; 689 *objp = obj_main; 690 return (func_ptr_type) obj_main->entry; 691 } 692 693 void * 694 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 695 { 696 void *ptr; 697 Elf_Addr target; 698 699 ptr = (void *)make_function_pointer(def, obj); 700 target = call_ifunc_resolver(ptr); 701 return ((void *)target); 702 } 703 704 /* 705 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 706 * Changes to this function should be applied there as well. 707 */ 708 Elf_Addr 709 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 710 { 711 const Elf_Rel *rel; 712 const Elf_Sym *def; 713 const Obj_Entry *defobj; 714 Elf_Addr *where; 715 Elf_Addr target; 716 RtldLockState lockstate; 717 718 rlock_acquire(rtld_bind_lock, &lockstate); 719 if (sigsetjmp(lockstate.env, 0) != 0) 720 lock_upgrade(rtld_bind_lock, &lockstate); 721 if (obj->pltrel) 722 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 723 else 724 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 725 726 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 727 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 728 NULL, &lockstate); 729 if (def == NULL) 730 rtld_die(); 731 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 732 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 733 else 734 target = (Elf_Addr)(defobj->relocbase + def->st_value); 735 736 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 737 defobj->strtab + def->st_name, basename(obj->path), 738 (void *)target, basename(defobj->path)); 739 740 /* 741 * Write the new contents for the jmpslot. Note that depending on 742 * architecture, the value which we need to return back to the 743 * lazy binding trampoline may or may not be the target 744 * address. The value returned from reloc_jmpslot() is the value 745 * that the trampoline needs. 746 */ 747 target = reloc_jmpslot(where, target, defobj, obj, rel); 748 lock_release(rtld_bind_lock, &lockstate); 749 return target; 750 } 751 752 /* 753 * Error reporting function. Use it like printf. If formats the message 754 * into a buffer, and sets things up so that the next call to dlerror() 755 * will return the message. 756 */ 757 void 758 _rtld_error(const char *fmt, ...) 759 { 760 static char buf[512]; 761 va_list ap; 762 763 va_start(ap, fmt); 764 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 765 error_message = buf; 766 va_end(ap); 767 } 768 769 /* 770 * Return a dynamically-allocated copy of the current error message, if any. 771 */ 772 static char * 773 errmsg_save(void) 774 { 775 return error_message == NULL ? NULL : xstrdup(error_message); 776 } 777 778 /* 779 * Restore the current error message from a copy which was previously saved 780 * by errmsg_save(). The copy is freed. 781 */ 782 static void 783 errmsg_restore(char *saved_msg) 784 { 785 if (saved_msg == NULL) 786 error_message = NULL; 787 else { 788 _rtld_error("%s", saved_msg); 789 free(saved_msg); 790 } 791 } 792 793 static const char * 794 basename(const char *name) 795 { 796 const char *p = strrchr(name, '/'); 797 return p != NULL ? p + 1 : name; 798 } 799 800 static struct utsname uts; 801 802 static char * 803 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 804 const char *subst, bool may_free) 805 { 806 char *p, *p1, *res, *resp; 807 int subst_len, kw_len, subst_count, old_len, new_len; 808 809 kw_len = strlen(kw); 810 811 /* 812 * First, count the number of the keyword occurrences, to 813 * preallocate the final string. 814 */ 815 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 816 p1 = strstr(p, kw); 817 if (p1 == NULL) 818 break; 819 } 820 821 /* 822 * If the keyword is not found, just return. 823 * 824 * Return non-substituted string if resolution failed. We 825 * cannot do anything more reasonable, the failure mode of the 826 * caller is unresolved library anyway. 827 */ 828 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 829 return (may_free ? real : xstrdup(real)); 830 if (obj != NULL) 831 subst = obj->origin_path; 832 833 /* 834 * There is indeed something to substitute. Calculate the 835 * length of the resulting string, and allocate it. 836 */ 837 subst_len = strlen(subst); 838 old_len = strlen(real); 839 new_len = old_len + (subst_len - kw_len) * subst_count; 840 res = xmalloc(new_len + 1); 841 842 /* 843 * Now, execute the substitution loop. 844 */ 845 for (p = real, resp = res, *resp = '\0';;) { 846 p1 = strstr(p, kw); 847 if (p1 != NULL) { 848 /* Copy the prefix before keyword. */ 849 memcpy(resp, p, p1 - p); 850 resp += p1 - p; 851 /* Keyword replacement. */ 852 memcpy(resp, subst, subst_len); 853 resp += subst_len; 854 *resp = '\0'; 855 p = p1 + kw_len; 856 } else 857 break; 858 } 859 860 /* Copy to the end of string and finish. */ 861 strcat(resp, p); 862 if (may_free) 863 free(real); 864 return (res); 865 } 866 867 static char * 868 origin_subst(Obj_Entry *obj, char *real) 869 { 870 char *res1, *res2, *res3, *res4; 871 872 if (obj == NULL || !trust) 873 return (xstrdup(real)); 874 if (uts.sysname[0] == '\0') { 875 if (uname(&uts) != 0) { 876 _rtld_error("utsname failed: %d", errno); 877 return (NULL); 878 } 879 } 880 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 881 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 882 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 883 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 884 return (res4); 885 } 886 887 void 888 rtld_die(void) 889 { 890 const char *msg = dlerror(); 891 892 if (msg == NULL) 893 msg = "Fatal error"; 894 rtld_fdputstr(STDERR_FILENO, msg); 895 rtld_fdputchar(STDERR_FILENO, '\n'); 896 _exit(1); 897 } 898 899 /* 900 * Process a shared object's DYNAMIC section, and save the important 901 * information in its Obj_Entry structure. 902 */ 903 static void 904 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 905 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 906 { 907 const Elf_Dyn *dynp; 908 Needed_Entry **needed_tail = &obj->needed; 909 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 910 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 911 const Elf_Hashelt *hashtab; 912 const Elf32_Word *hashval; 913 Elf32_Word bkt, nmaskwords; 914 int bloom_size32; 915 int plttype = DT_REL; 916 917 *dyn_rpath = NULL; 918 *dyn_soname = NULL; 919 *dyn_runpath = NULL; 920 921 obj->bind_now = false; 922 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 923 switch (dynp->d_tag) { 924 925 case DT_REL: 926 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 927 break; 928 929 case DT_RELSZ: 930 obj->relsize = dynp->d_un.d_val; 931 break; 932 933 case DT_RELENT: 934 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 935 break; 936 937 case DT_JMPREL: 938 obj->pltrel = (const Elf_Rel *) 939 (obj->relocbase + dynp->d_un.d_ptr); 940 break; 941 942 case DT_PLTRELSZ: 943 obj->pltrelsize = dynp->d_un.d_val; 944 break; 945 946 case DT_RELA: 947 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 948 break; 949 950 case DT_RELASZ: 951 obj->relasize = dynp->d_un.d_val; 952 break; 953 954 case DT_RELAENT: 955 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 956 break; 957 958 case DT_PLTREL: 959 plttype = dynp->d_un.d_val; 960 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 961 break; 962 963 case DT_SYMTAB: 964 obj->symtab = (const Elf_Sym *) 965 (obj->relocbase + dynp->d_un.d_ptr); 966 break; 967 968 case DT_SYMENT: 969 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 970 break; 971 972 case DT_STRTAB: 973 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 974 break; 975 976 case DT_STRSZ: 977 obj->strsize = dynp->d_un.d_val; 978 break; 979 980 case DT_VERNEED: 981 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 982 dynp->d_un.d_val); 983 break; 984 985 case DT_VERNEEDNUM: 986 obj->verneednum = dynp->d_un.d_val; 987 break; 988 989 case DT_VERDEF: 990 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 991 dynp->d_un.d_val); 992 break; 993 994 case DT_VERDEFNUM: 995 obj->verdefnum = dynp->d_un.d_val; 996 break; 997 998 case DT_VERSYM: 999 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1000 dynp->d_un.d_val); 1001 break; 1002 1003 case DT_HASH: 1004 { 1005 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1006 dynp->d_un.d_ptr); 1007 obj->nbuckets = hashtab[0]; 1008 obj->nchains = hashtab[1]; 1009 obj->buckets = hashtab + 2; 1010 obj->chains = obj->buckets + obj->nbuckets; 1011 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1012 obj->buckets != NULL; 1013 } 1014 break; 1015 1016 case DT_GNU_HASH: 1017 { 1018 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1019 dynp->d_un.d_ptr); 1020 obj->nbuckets_gnu = hashtab[0]; 1021 obj->symndx_gnu = hashtab[1]; 1022 nmaskwords = hashtab[2]; 1023 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1024 obj->maskwords_bm_gnu = nmaskwords - 1; 1025 obj->shift2_gnu = hashtab[3]; 1026 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1027 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1028 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1029 obj->symndx_gnu; 1030 /* Number of bitmask words is required to be power of 2 */ 1031 obj->valid_hash_gnu = powerof2(nmaskwords) && 1032 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1033 } 1034 break; 1035 1036 case DT_NEEDED: 1037 if (!obj->rtld) { 1038 Needed_Entry *nep = NEW(Needed_Entry); 1039 nep->name = dynp->d_un.d_val; 1040 nep->obj = NULL; 1041 nep->next = NULL; 1042 1043 *needed_tail = nep; 1044 needed_tail = &nep->next; 1045 } 1046 break; 1047 1048 case DT_FILTER: 1049 if (!obj->rtld) { 1050 Needed_Entry *nep = NEW(Needed_Entry); 1051 nep->name = dynp->d_un.d_val; 1052 nep->obj = NULL; 1053 nep->next = NULL; 1054 1055 *needed_filtees_tail = nep; 1056 needed_filtees_tail = &nep->next; 1057 } 1058 break; 1059 1060 case DT_AUXILIARY: 1061 if (!obj->rtld) { 1062 Needed_Entry *nep = NEW(Needed_Entry); 1063 nep->name = dynp->d_un.d_val; 1064 nep->obj = NULL; 1065 nep->next = NULL; 1066 1067 *needed_aux_filtees_tail = nep; 1068 needed_aux_filtees_tail = &nep->next; 1069 } 1070 break; 1071 1072 case DT_PLTGOT: 1073 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1074 break; 1075 1076 case DT_TEXTREL: 1077 obj->textrel = true; 1078 break; 1079 1080 case DT_SYMBOLIC: 1081 obj->symbolic = true; 1082 break; 1083 1084 case DT_RPATH: 1085 /* 1086 * We have to wait until later to process this, because we 1087 * might not have gotten the address of the string table yet. 1088 */ 1089 *dyn_rpath = dynp; 1090 break; 1091 1092 case DT_SONAME: 1093 *dyn_soname = dynp; 1094 break; 1095 1096 case DT_RUNPATH: 1097 *dyn_runpath = dynp; 1098 break; 1099 1100 case DT_INIT: 1101 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1102 break; 1103 1104 case DT_PREINIT_ARRAY: 1105 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1106 break; 1107 1108 case DT_PREINIT_ARRAYSZ: 1109 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1110 break; 1111 1112 case DT_INIT_ARRAY: 1113 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1114 break; 1115 1116 case DT_INIT_ARRAYSZ: 1117 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1118 break; 1119 1120 case DT_FINI: 1121 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1122 break; 1123 1124 case DT_FINI_ARRAY: 1125 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1126 break; 1127 1128 case DT_FINI_ARRAYSZ: 1129 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1130 break; 1131 1132 /* 1133 * Don't process DT_DEBUG on MIPS as the dynamic section 1134 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1135 */ 1136 1137 #ifndef __mips__ 1138 case DT_DEBUG: 1139 if (!early) 1140 dbg("Filling in DT_DEBUG entry"); 1141 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1142 break; 1143 #endif 1144 1145 case DT_FLAGS: 1146 if (dynp->d_un.d_val & DF_ORIGIN) 1147 obj->z_origin = true; 1148 if (dynp->d_un.d_val & DF_SYMBOLIC) 1149 obj->symbolic = true; 1150 if (dynp->d_un.d_val & DF_TEXTREL) 1151 obj->textrel = true; 1152 if (dynp->d_un.d_val & DF_BIND_NOW) 1153 obj->bind_now = true; 1154 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1155 ;*/ 1156 break; 1157 #ifdef __mips__ 1158 case DT_MIPS_LOCAL_GOTNO: 1159 obj->local_gotno = dynp->d_un.d_val; 1160 break; 1161 1162 case DT_MIPS_SYMTABNO: 1163 obj->symtabno = dynp->d_un.d_val; 1164 break; 1165 1166 case DT_MIPS_GOTSYM: 1167 obj->gotsym = dynp->d_un.d_val; 1168 break; 1169 1170 case DT_MIPS_RLD_MAP: 1171 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1172 break; 1173 #endif 1174 1175 #ifdef __powerpc64__ 1176 case DT_PPC64_GLINK: 1177 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1178 break; 1179 #endif 1180 1181 case DT_FLAGS_1: 1182 if (dynp->d_un.d_val & DF_1_NOOPEN) 1183 obj->z_noopen = true; 1184 if (dynp->d_un.d_val & DF_1_ORIGIN) 1185 obj->z_origin = true; 1186 if (dynp->d_un.d_val & DF_1_GLOBAL) 1187 obj->z_global = true; 1188 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1189 obj->bind_now = true; 1190 if (dynp->d_un.d_val & DF_1_NODELETE) 1191 obj->z_nodelete = true; 1192 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1193 obj->z_loadfltr = true; 1194 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1195 obj->z_interpose = true; 1196 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1197 obj->z_nodeflib = true; 1198 break; 1199 1200 default: 1201 if (!early) { 1202 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1203 (long)dynp->d_tag); 1204 } 1205 break; 1206 } 1207 } 1208 1209 obj->traced = false; 1210 1211 if (plttype == DT_RELA) { 1212 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1213 obj->pltrel = NULL; 1214 obj->pltrelasize = obj->pltrelsize; 1215 obj->pltrelsize = 0; 1216 } 1217 1218 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1219 if (obj->valid_hash_sysv) 1220 obj->dynsymcount = obj->nchains; 1221 else if (obj->valid_hash_gnu) { 1222 obj->dynsymcount = 0; 1223 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1224 if (obj->buckets_gnu[bkt] == 0) 1225 continue; 1226 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1227 do 1228 obj->dynsymcount++; 1229 while ((*hashval++ & 1u) == 0); 1230 } 1231 obj->dynsymcount += obj->symndx_gnu; 1232 } 1233 } 1234 1235 static bool 1236 obj_resolve_origin(Obj_Entry *obj) 1237 { 1238 1239 if (obj->origin_path != NULL) 1240 return (true); 1241 obj->origin_path = xmalloc(PATH_MAX); 1242 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1243 } 1244 1245 static void 1246 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1247 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1248 { 1249 1250 if (obj->z_origin && !obj_resolve_origin(obj)) 1251 rtld_die(); 1252 1253 if (dyn_runpath != NULL) { 1254 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1255 obj->runpath = origin_subst(obj, obj->runpath); 1256 } else if (dyn_rpath != NULL) { 1257 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1258 obj->rpath = origin_subst(obj, obj->rpath); 1259 } 1260 if (dyn_soname != NULL) 1261 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1262 } 1263 1264 static void 1265 digest_dynamic(Obj_Entry *obj, int early) 1266 { 1267 const Elf_Dyn *dyn_rpath; 1268 const Elf_Dyn *dyn_soname; 1269 const Elf_Dyn *dyn_runpath; 1270 1271 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1272 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1273 } 1274 1275 /* 1276 * Process a shared object's program header. This is used only for the 1277 * main program, when the kernel has already loaded the main program 1278 * into memory before calling the dynamic linker. It creates and 1279 * returns an Obj_Entry structure. 1280 */ 1281 static Obj_Entry * 1282 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1283 { 1284 Obj_Entry *obj; 1285 const Elf_Phdr *phlimit = phdr + phnum; 1286 const Elf_Phdr *ph; 1287 Elf_Addr note_start, note_end; 1288 int nsegs = 0; 1289 1290 obj = obj_new(); 1291 for (ph = phdr; ph < phlimit; ph++) { 1292 if (ph->p_type != PT_PHDR) 1293 continue; 1294 1295 obj->phdr = phdr; 1296 obj->phsize = ph->p_memsz; 1297 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1298 break; 1299 } 1300 1301 obj->stack_flags = PF_X | PF_R | PF_W; 1302 1303 for (ph = phdr; ph < phlimit; ph++) { 1304 switch (ph->p_type) { 1305 1306 case PT_INTERP: 1307 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1308 break; 1309 1310 case PT_LOAD: 1311 if (nsegs == 0) { /* First load segment */ 1312 obj->vaddrbase = trunc_page(ph->p_vaddr); 1313 obj->mapbase = obj->vaddrbase + obj->relocbase; 1314 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1315 obj->vaddrbase; 1316 } else { /* Last load segment */ 1317 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1318 obj->vaddrbase; 1319 } 1320 nsegs++; 1321 break; 1322 1323 case PT_DYNAMIC: 1324 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1325 break; 1326 1327 case PT_TLS: 1328 obj->tlsindex = 1; 1329 obj->tlssize = ph->p_memsz; 1330 obj->tlsalign = ph->p_align; 1331 obj->tlsinitsize = ph->p_filesz; 1332 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1333 break; 1334 1335 case PT_GNU_STACK: 1336 obj->stack_flags = ph->p_flags; 1337 break; 1338 1339 case PT_GNU_RELRO: 1340 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1341 obj->relro_size = round_page(ph->p_memsz); 1342 break; 1343 1344 case PT_NOTE: 1345 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1346 note_end = note_start + ph->p_filesz; 1347 digest_notes(obj, note_start, note_end); 1348 break; 1349 } 1350 } 1351 if (nsegs < 1) { 1352 _rtld_error("%s: too few PT_LOAD segments", path); 1353 return NULL; 1354 } 1355 1356 obj->entry = entry; 1357 return obj; 1358 } 1359 1360 void 1361 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1362 { 1363 const Elf_Note *note; 1364 const char *note_name; 1365 uintptr_t p; 1366 1367 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1368 note = (const Elf_Note *)((const char *)(note + 1) + 1369 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1370 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1371 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1372 note->n_descsz != sizeof(int32_t)) 1373 continue; 1374 if (note->n_type != NT_FREEBSD_ABI_TAG && 1375 note->n_type != NT_FREEBSD_NOINIT_TAG) 1376 continue; 1377 note_name = (const char *)(note + 1); 1378 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1379 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1380 continue; 1381 switch (note->n_type) { 1382 case NT_FREEBSD_ABI_TAG: 1383 /* FreeBSD osrel note */ 1384 p = (uintptr_t)(note + 1); 1385 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1386 obj->osrel = *(const int32_t *)(p); 1387 dbg("note osrel %d", obj->osrel); 1388 break; 1389 case NT_FREEBSD_NOINIT_TAG: 1390 /* FreeBSD 'crt does not call init' note */ 1391 obj->crt_no_init = true; 1392 dbg("note crt_no_init"); 1393 break; 1394 } 1395 } 1396 } 1397 1398 static Obj_Entry * 1399 dlcheck(void *handle) 1400 { 1401 Obj_Entry *obj; 1402 1403 TAILQ_FOREACH(obj, &obj_list, next) { 1404 if (obj == (Obj_Entry *) handle) 1405 break; 1406 } 1407 1408 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1409 _rtld_error("Invalid shared object handle %p", handle); 1410 return NULL; 1411 } 1412 return obj; 1413 } 1414 1415 /* 1416 * If the given object is already in the donelist, return true. Otherwise 1417 * add the object to the list and return false. 1418 */ 1419 static bool 1420 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1421 { 1422 unsigned int i; 1423 1424 for (i = 0; i < dlp->num_used; i++) 1425 if (dlp->objs[i] == obj) 1426 return true; 1427 /* 1428 * Our donelist allocation should always be sufficient. But if 1429 * our threads locking isn't working properly, more shared objects 1430 * could have been loaded since we allocated the list. That should 1431 * never happen, but we'll handle it properly just in case it does. 1432 */ 1433 if (dlp->num_used < dlp->num_alloc) 1434 dlp->objs[dlp->num_used++] = obj; 1435 return false; 1436 } 1437 1438 /* 1439 * Hash function for symbol table lookup. Don't even think about changing 1440 * this. It is specified by the System V ABI. 1441 */ 1442 unsigned long 1443 elf_hash(const char *name) 1444 { 1445 const unsigned char *p = (const unsigned char *) name; 1446 unsigned long h = 0; 1447 unsigned long g; 1448 1449 while (*p != '\0') { 1450 h = (h << 4) + *p++; 1451 if ((g = h & 0xf0000000) != 0) 1452 h ^= g >> 24; 1453 h &= ~g; 1454 } 1455 return h; 1456 } 1457 1458 /* 1459 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1460 * unsigned in case it's implemented with a wider type. 1461 */ 1462 static uint32_t 1463 gnu_hash(const char *s) 1464 { 1465 uint32_t h; 1466 unsigned char c; 1467 1468 h = 5381; 1469 for (c = *s; c != '\0'; c = *++s) 1470 h = h * 33 + c; 1471 return (h & 0xffffffff); 1472 } 1473 1474 1475 /* 1476 * Find the library with the given name, and return its full pathname. 1477 * The returned string is dynamically allocated. Generates an error 1478 * message and returns NULL if the library cannot be found. 1479 * 1480 * If the second argument is non-NULL, then it refers to an already- 1481 * loaded shared object, whose library search path will be searched. 1482 * 1483 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1484 * descriptor (which is close-on-exec) will be passed out via the third 1485 * argument. 1486 * 1487 * The search order is: 1488 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1489 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1490 * LD_LIBRARY_PATH 1491 * DT_RUNPATH in the referencing file 1492 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1493 * from list) 1494 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1495 * 1496 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1497 */ 1498 static char * 1499 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1500 { 1501 char *pathname; 1502 char *name; 1503 bool nodeflib, objgiven; 1504 1505 objgiven = refobj != NULL; 1506 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1507 if (xname[0] != '/' && !trust) { 1508 _rtld_error("Absolute pathname required for shared object \"%s\"", 1509 xname); 1510 return NULL; 1511 } 1512 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1513 __DECONST(char *, xname))); 1514 } 1515 1516 if (libmap_disable || !objgiven || 1517 (name = lm_find(refobj->path, xname)) == NULL) 1518 name = (char *)xname; 1519 1520 dbg(" Searching for \"%s\"", name); 1521 1522 /* 1523 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1524 * back to pre-conforming behaviour if user requested so with 1525 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1526 * nodeflib. 1527 */ 1528 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1529 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1530 (refobj != NULL && 1531 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1532 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1533 (pathname = search_library_path(name, gethints(false))) != NULL || 1534 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1535 return (pathname); 1536 } else { 1537 nodeflib = objgiven ? refobj->z_nodeflib : false; 1538 if ((objgiven && 1539 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1540 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1541 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1542 (pathname = search_library_path(name, ld_library_path)) != NULL || 1543 (objgiven && 1544 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1545 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1546 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1547 (objgiven && !nodeflib && 1548 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1549 return (pathname); 1550 } 1551 1552 if (objgiven && refobj->path != NULL) { 1553 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1554 name, basename(refobj->path)); 1555 } else { 1556 _rtld_error("Shared object \"%s\" not found", name); 1557 } 1558 return NULL; 1559 } 1560 1561 /* 1562 * Given a symbol number in a referencing object, find the corresponding 1563 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1564 * no definition was found. Returns a pointer to the Obj_Entry of the 1565 * defining object via the reference parameter DEFOBJ_OUT. 1566 */ 1567 const Elf_Sym * 1568 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1569 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1570 RtldLockState *lockstate) 1571 { 1572 const Elf_Sym *ref; 1573 const Elf_Sym *def; 1574 const Obj_Entry *defobj; 1575 SymLook req; 1576 const char *name; 1577 int res; 1578 1579 /* 1580 * If we have already found this symbol, get the information from 1581 * the cache. 1582 */ 1583 if (symnum >= refobj->dynsymcount) 1584 return NULL; /* Bad object */ 1585 if (cache != NULL && cache[symnum].sym != NULL) { 1586 *defobj_out = cache[symnum].obj; 1587 return cache[symnum].sym; 1588 } 1589 1590 ref = refobj->symtab + symnum; 1591 name = refobj->strtab + ref->st_name; 1592 def = NULL; 1593 defobj = NULL; 1594 1595 /* 1596 * We don't have to do a full scale lookup if the symbol is local. 1597 * We know it will bind to the instance in this load module; to 1598 * which we already have a pointer (ie ref). By not doing a lookup, 1599 * we not only improve performance, but it also avoids unresolvable 1600 * symbols when local symbols are not in the hash table. This has 1601 * been seen with the ia64 toolchain. 1602 */ 1603 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1604 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1605 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1606 symnum); 1607 } 1608 symlook_init(&req, name); 1609 req.flags = flags; 1610 req.ventry = fetch_ventry(refobj, symnum); 1611 req.lockstate = lockstate; 1612 res = symlook_default(&req, refobj); 1613 if (res == 0) { 1614 def = req.sym_out; 1615 defobj = req.defobj_out; 1616 } 1617 } else { 1618 def = ref; 1619 defobj = refobj; 1620 } 1621 1622 /* 1623 * If we found no definition and the reference is weak, treat the 1624 * symbol as having the value zero. 1625 */ 1626 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1627 def = &sym_zero; 1628 defobj = obj_main; 1629 } 1630 1631 if (def != NULL) { 1632 *defobj_out = defobj; 1633 /* Record the information in the cache to avoid subsequent lookups. */ 1634 if (cache != NULL) { 1635 cache[symnum].sym = def; 1636 cache[symnum].obj = defobj; 1637 } 1638 } else { 1639 if (refobj != &obj_rtld) 1640 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1641 } 1642 return def; 1643 } 1644 1645 /* 1646 * Return the search path from the ldconfig hints file, reading it if 1647 * necessary. If nostdlib is true, then the default search paths are 1648 * not added to result. 1649 * 1650 * Returns NULL if there are problems with the hints file, 1651 * or if the search path there is empty. 1652 */ 1653 static const char * 1654 gethints(bool nostdlib) 1655 { 1656 static char *hints, *filtered_path; 1657 static struct elfhints_hdr hdr; 1658 struct fill_search_info_args sargs, hargs; 1659 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1660 struct dl_serpath *SLPpath, *hintpath; 1661 char *p; 1662 struct stat hint_stat; 1663 unsigned int SLPndx, hintndx, fndx, fcount; 1664 int fd; 1665 size_t flen; 1666 uint32_t dl; 1667 bool skip; 1668 1669 /* First call, read the hints file */ 1670 if (hints == NULL) { 1671 /* Keep from trying again in case the hints file is bad. */ 1672 hints = ""; 1673 1674 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1675 return (NULL); 1676 1677 /* 1678 * Check of hdr.dirlistlen value against type limit 1679 * intends to pacify static analyzers. Further 1680 * paranoia leads to checks that dirlist is fully 1681 * contained in the file range. 1682 */ 1683 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1684 hdr.magic != ELFHINTS_MAGIC || 1685 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1686 fstat(fd, &hint_stat) == -1) { 1687 cleanup1: 1688 close(fd); 1689 hdr.dirlistlen = 0; 1690 return (NULL); 1691 } 1692 dl = hdr.strtab; 1693 if (dl + hdr.dirlist < dl) 1694 goto cleanup1; 1695 dl += hdr.dirlist; 1696 if (dl + hdr.dirlistlen < dl) 1697 goto cleanup1; 1698 dl += hdr.dirlistlen; 1699 if (dl > hint_stat.st_size) 1700 goto cleanup1; 1701 p = xmalloc(hdr.dirlistlen + 1); 1702 1703 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1704 read(fd, p, hdr.dirlistlen + 1) != 1705 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1706 free(p); 1707 goto cleanup1; 1708 } 1709 hints = p; 1710 close(fd); 1711 } 1712 1713 /* 1714 * If caller agreed to receive list which includes the default 1715 * paths, we are done. Otherwise, if we still did not 1716 * calculated filtered result, do it now. 1717 */ 1718 if (!nostdlib) 1719 return (hints[0] != '\0' ? hints : NULL); 1720 if (filtered_path != NULL) 1721 goto filt_ret; 1722 1723 /* 1724 * Obtain the list of all configured search paths, and the 1725 * list of the default paths. 1726 * 1727 * First estimate the size of the results. 1728 */ 1729 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1730 smeta.dls_cnt = 0; 1731 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1732 hmeta.dls_cnt = 0; 1733 1734 sargs.request = RTLD_DI_SERINFOSIZE; 1735 sargs.serinfo = &smeta; 1736 hargs.request = RTLD_DI_SERINFOSIZE; 1737 hargs.serinfo = &hmeta; 1738 1739 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1740 path_enumerate(hints, fill_search_info, &hargs); 1741 1742 SLPinfo = xmalloc(smeta.dls_size); 1743 hintinfo = xmalloc(hmeta.dls_size); 1744 1745 /* 1746 * Next fetch both sets of paths. 1747 */ 1748 sargs.request = RTLD_DI_SERINFO; 1749 sargs.serinfo = SLPinfo; 1750 sargs.serpath = &SLPinfo->dls_serpath[0]; 1751 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1752 1753 hargs.request = RTLD_DI_SERINFO; 1754 hargs.serinfo = hintinfo; 1755 hargs.serpath = &hintinfo->dls_serpath[0]; 1756 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1757 1758 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1759 path_enumerate(hints, fill_search_info, &hargs); 1760 1761 /* 1762 * Now calculate the difference between two sets, by excluding 1763 * standard paths from the full set. 1764 */ 1765 fndx = 0; 1766 fcount = 0; 1767 filtered_path = xmalloc(hdr.dirlistlen + 1); 1768 hintpath = &hintinfo->dls_serpath[0]; 1769 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1770 skip = false; 1771 SLPpath = &SLPinfo->dls_serpath[0]; 1772 /* 1773 * Check each standard path against current. 1774 */ 1775 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1776 /* matched, skip the path */ 1777 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1778 skip = true; 1779 break; 1780 } 1781 } 1782 if (skip) 1783 continue; 1784 /* 1785 * Not matched against any standard path, add the path 1786 * to result. Separate consequtive paths with ':'. 1787 */ 1788 if (fcount > 0) { 1789 filtered_path[fndx] = ':'; 1790 fndx++; 1791 } 1792 fcount++; 1793 flen = strlen(hintpath->dls_name); 1794 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1795 fndx += flen; 1796 } 1797 filtered_path[fndx] = '\0'; 1798 1799 free(SLPinfo); 1800 free(hintinfo); 1801 1802 filt_ret: 1803 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1804 } 1805 1806 static void 1807 init_dag(Obj_Entry *root) 1808 { 1809 const Needed_Entry *needed; 1810 const Objlist_Entry *elm; 1811 DoneList donelist; 1812 1813 if (root->dag_inited) 1814 return; 1815 donelist_init(&donelist); 1816 1817 /* Root object belongs to own DAG. */ 1818 objlist_push_tail(&root->dldags, root); 1819 objlist_push_tail(&root->dagmembers, root); 1820 donelist_check(&donelist, root); 1821 1822 /* 1823 * Add dependencies of root object to DAG in breadth order 1824 * by exploiting the fact that each new object get added 1825 * to the tail of the dagmembers list. 1826 */ 1827 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1828 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1829 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1830 continue; 1831 objlist_push_tail(&needed->obj->dldags, root); 1832 objlist_push_tail(&root->dagmembers, needed->obj); 1833 } 1834 } 1835 root->dag_inited = true; 1836 } 1837 1838 static void 1839 init_marker(Obj_Entry *marker) 1840 { 1841 1842 bzero(marker, sizeof(*marker)); 1843 marker->marker = true; 1844 } 1845 1846 Obj_Entry * 1847 globallist_curr(const Obj_Entry *obj) 1848 { 1849 1850 for (;;) { 1851 if (obj == NULL) 1852 return (NULL); 1853 if (!obj->marker) 1854 return (__DECONST(Obj_Entry *, obj)); 1855 obj = TAILQ_PREV(obj, obj_entry_q, next); 1856 } 1857 } 1858 1859 Obj_Entry * 1860 globallist_next(const Obj_Entry *obj) 1861 { 1862 1863 for (;;) { 1864 obj = TAILQ_NEXT(obj, next); 1865 if (obj == NULL) 1866 return (NULL); 1867 if (!obj->marker) 1868 return (__DECONST(Obj_Entry *, obj)); 1869 } 1870 } 1871 1872 /* Prevent the object from being unmapped while the bind lock is dropped. */ 1873 static void 1874 hold_object(Obj_Entry *obj) 1875 { 1876 1877 obj->holdcount++; 1878 } 1879 1880 static void 1881 unhold_object(Obj_Entry *obj) 1882 { 1883 1884 assert(obj->holdcount > 0); 1885 if (--obj->holdcount == 0 && obj->unholdfree) 1886 release_object(obj); 1887 } 1888 1889 static void 1890 process_z(Obj_Entry *root) 1891 { 1892 const Objlist_Entry *elm; 1893 Obj_Entry *obj; 1894 1895 /* 1896 * Walk over object DAG and process every dependent object 1897 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1898 * to grow their own DAG. 1899 * 1900 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1901 * symlook_global() to work. 1902 * 1903 * For DF_1_NODELETE, the DAG should have its reference upped. 1904 */ 1905 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1906 obj = elm->obj; 1907 if (obj == NULL) 1908 continue; 1909 if (obj->z_nodelete && !obj->ref_nodel) { 1910 dbg("obj %s -z nodelete", obj->path); 1911 init_dag(obj); 1912 ref_dag(obj); 1913 obj->ref_nodel = true; 1914 } 1915 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1916 dbg("obj %s -z global", obj->path); 1917 objlist_push_tail(&list_global, obj); 1918 init_dag(obj); 1919 } 1920 } 1921 } 1922 /* 1923 * Initialize the dynamic linker. The argument is the address at which 1924 * the dynamic linker has been mapped into memory. The primary task of 1925 * this function is to relocate the dynamic linker. 1926 */ 1927 static void 1928 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1929 { 1930 Obj_Entry objtmp; /* Temporary rtld object */ 1931 const Elf_Ehdr *ehdr; 1932 const Elf_Dyn *dyn_rpath; 1933 const Elf_Dyn *dyn_soname; 1934 const Elf_Dyn *dyn_runpath; 1935 1936 #ifdef RTLD_INIT_PAGESIZES_EARLY 1937 /* The page size is required by the dynamic memory allocator. */ 1938 init_pagesizes(aux_info); 1939 #endif 1940 1941 /* 1942 * Conjure up an Obj_Entry structure for the dynamic linker. 1943 * 1944 * The "path" member can't be initialized yet because string constants 1945 * cannot yet be accessed. Below we will set it correctly. 1946 */ 1947 memset(&objtmp, 0, sizeof(objtmp)); 1948 objtmp.path = NULL; 1949 objtmp.rtld = true; 1950 objtmp.mapbase = mapbase; 1951 #ifdef PIC 1952 objtmp.relocbase = mapbase; 1953 #endif 1954 1955 objtmp.dynamic = rtld_dynamic(&objtmp); 1956 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1957 assert(objtmp.needed == NULL); 1958 #if !defined(__mips__) 1959 /* MIPS has a bogus DT_TEXTREL. */ 1960 assert(!objtmp.textrel); 1961 #endif 1962 /* 1963 * Temporarily put the dynamic linker entry into the object list, so 1964 * that symbols can be found. 1965 */ 1966 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1967 1968 ehdr = (Elf_Ehdr *)mapbase; 1969 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1970 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1971 1972 /* Initialize the object list. */ 1973 TAILQ_INIT(&obj_list); 1974 1975 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1976 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1977 1978 #ifndef RTLD_INIT_PAGESIZES_EARLY 1979 /* The page size is required by the dynamic memory allocator. */ 1980 init_pagesizes(aux_info); 1981 #endif 1982 1983 if (aux_info[AT_OSRELDATE] != NULL) 1984 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1985 1986 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1987 1988 /* Replace the path with a dynamically allocated copy. */ 1989 obj_rtld.path = xstrdup(ld_path_rtld); 1990 1991 r_debug.r_brk = r_debug_state; 1992 r_debug.r_state = RT_CONSISTENT; 1993 } 1994 1995 /* 1996 * Retrieve the array of supported page sizes. The kernel provides the page 1997 * sizes in increasing order. 1998 */ 1999 static void 2000 init_pagesizes(Elf_Auxinfo **aux_info) 2001 { 2002 static size_t psa[MAXPAGESIZES]; 2003 int mib[2]; 2004 size_t len, size; 2005 2006 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2007 NULL) { 2008 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2009 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2010 } else { 2011 len = 2; 2012 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2013 size = sizeof(psa); 2014 else { 2015 /* As a fallback, retrieve the base page size. */ 2016 size = sizeof(psa[0]); 2017 if (aux_info[AT_PAGESZ] != NULL) { 2018 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2019 goto psa_filled; 2020 } else { 2021 mib[0] = CTL_HW; 2022 mib[1] = HW_PAGESIZE; 2023 len = 2; 2024 } 2025 } 2026 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2027 _rtld_error("sysctl for hw.pagesize(s) failed"); 2028 rtld_die(); 2029 } 2030 psa_filled: 2031 pagesizes = psa; 2032 } 2033 npagesizes = size / sizeof(pagesizes[0]); 2034 /* Discard any invalid entries at the end of the array. */ 2035 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2036 npagesizes--; 2037 } 2038 2039 /* 2040 * Add the init functions from a needed object list (and its recursive 2041 * needed objects) to "list". This is not used directly; it is a helper 2042 * function for initlist_add_objects(). The write lock must be held 2043 * when this function is called. 2044 */ 2045 static void 2046 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2047 { 2048 /* Recursively process the successor needed objects. */ 2049 if (needed->next != NULL) 2050 initlist_add_neededs(needed->next, list); 2051 2052 /* Process the current needed object. */ 2053 if (needed->obj != NULL) 2054 initlist_add_objects(needed->obj, needed->obj, list); 2055 } 2056 2057 /* 2058 * Scan all of the DAGs rooted in the range of objects from "obj" to 2059 * "tail" and add their init functions to "list". This recurses over 2060 * the DAGs and ensure the proper init ordering such that each object's 2061 * needed libraries are initialized before the object itself. At the 2062 * same time, this function adds the objects to the global finalization 2063 * list "list_fini" in the opposite order. The write lock must be 2064 * held when this function is called. 2065 */ 2066 static void 2067 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2068 { 2069 Obj_Entry *nobj; 2070 2071 if (obj->init_scanned || obj->init_done) 2072 return; 2073 obj->init_scanned = true; 2074 2075 /* Recursively process the successor objects. */ 2076 nobj = globallist_next(obj); 2077 if (nobj != NULL && obj != tail) 2078 initlist_add_objects(nobj, tail, list); 2079 2080 /* Recursively process the needed objects. */ 2081 if (obj->needed != NULL) 2082 initlist_add_neededs(obj->needed, list); 2083 if (obj->needed_filtees != NULL) 2084 initlist_add_neededs(obj->needed_filtees, list); 2085 if (obj->needed_aux_filtees != NULL) 2086 initlist_add_neededs(obj->needed_aux_filtees, list); 2087 2088 /* Add the object to the init list. */ 2089 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2090 obj->init_array != (Elf_Addr)NULL) 2091 objlist_push_tail(list, obj); 2092 2093 /* Add the object to the global fini list in the reverse order. */ 2094 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2095 && !obj->on_fini_list) { 2096 objlist_push_head(&list_fini, obj); 2097 obj->on_fini_list = true; 2098 } 2099 } 2100 2101 #ifndef FPTR_TARGET 2102 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2103 #endif 2104 2105 static void 2106 free_needed_filtees(Needed_Entry *n) 2107 { 2108 Needed_Entry *needed, *needed1; 2109 2110 for (needed = n; needed != NULL; needed = needed->next) { 2111 if (needed->obj != NULL) { 2112 dlclose(needed->obj); 2113 needed->obj = NULL; 2114 } 2115 } 2116 for (needed = n; needed != NULL; needed = needed1) { 2117 needed1 = needed->next; 2118 free(needed); 2119 } 2120 } 2121 2122 static void 2123 unload_filtees(Obj_Entry *obj) 2124 { 2125 2126 free_needed_filtees(obj->needed_filtees); 2127 obj->needed_filtees = NULL; 2128 free_needed_filtees(obj->needed_aux_filtees); 2129 obj->needed_aux_filtees = NULL; 2130 obj->filtees_loaded = false; 2131 } 2132 2133 static void 2134 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2135 RtldLockState *lockstate) 2136 { 2137 2138 for (; needed != NULL; needed = needed->next) { 2139 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2140 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2141 RTLD_LOCAL, lockstate); 2142 } 2143 } 2144 2145 static void 2146 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2147 { 2148 2149 lock_restart_for_upgrade(lockstate); 2150 if (!obj->filtees_loaded) { 2151 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2152 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2153 obj->filtees_loaded = true; 2154 } 2155 } 2156 2157 static int 2158 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2159 { 2160 Obj_Entry *obj1; 2161 2162 for (; needed != NULL; needed = needed->next) { 2163 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2164 flags & ~RTLD_LO_NOLOAD); 2165 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2166 return (-1); 2167 } 2168 return (0); 2169 } 2170 2171 /* 2172 * Given a shared object, traverse its list of needed objects, and load 2173 * each of them. Returns 0 on success. Generates an error message and 2174 * returns -1 on failure. 2175 */ 2176 static int 2177 load_needed_objects(Obj_Entry *first, int flags) 2178 { 2179 Obj_Entry *obj; 2180 2181 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2182 if (obj->marker) 2183 continue; 2184 if (process_needed(obj, obj->needed, flags) == -1) 2185 return (-1); 2186 } 2187 return (0); 2188 } 2189 2190 static int 2191 load_preload_objects(void) 2192 { 2193 char *p = ld_preload; 2194 Obj_Entry *obj; 2195 static const char delim[] = " \t:;"; 2196 2197 if (p == NULL) 2198 return 0; 2199 2200 p += strspn(p, delim); 2201 while (*p != '\0') { 2202 size_t len = strcspn(p, delim); 2203 char savech; 2204 2205 savech = p[len]; 2206 p[len] = '\0'; 2207 obj = load_object(p, -1, NULL, 0); 2208 if (obj == NULL) 2209 return -1; /* XXX - cleanup */ 2210 obj->z_interpose = true; 2211 p[len] = savech; 2212 p += len; 2213 p += strspn(p, delim); 2214 } 2215 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2216 return 0; 2217 } 2218 2219 static const char * 2220 printable_path(const char *path) 2221 { 2222 2223 return (path == NULL ? "<unknown>" : path); 2224 } 2225 2226 /* 2227 * Load a shared object into memory, if it is not already loaded. The 2228 * object may be specified by name or by user-supplied file descriptor 2229 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2230 * duplicate is. 2231 * 2232 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2233 * on failure. 2234 */ 2235 static Obj_Entry * 2236 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2237 { 2238 Obj_Entry *obj; 2239 int fd; 2240 struct stat sb; 2241 char *path; 2242 2243 fd = -1; 2244 if (name != NULL) { 2245 TAILQ_FOREACH(obj, &obj_list, next) { 2246 if (obj->marker || obj->doomed) 2247 continue; 2248 if (object_match_name(obj, name)) 2249 return (obj); 2250 } 2251 2252 path = find_library(name, refobj, &fd); 2253 if (path == NULL) 2254 return (NULL); 2255 } else 2256 path = NULL; 2257 2258 if (fd >= 0) { 2259 /* 2260 * search_library_pathfds() opens a fresh file descriptor for the 2261 * library, so there is no need to dup(). 2262 */ 2263 } else if (fd_u == -1) { 2264 /* 2265 * If we didn't find a match by pathname, or the name is not 2266 * supplied, open the file and check again by device and inode. 2267 * This avoids false mismatches caused by multiple links or ".." 2268 * in pathnames. 2269 * 2270 * To avoid a race, we open the file and use fstat() rather than 2271 * using stat(). 2272 */ 2273 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2274 _rtld_error("Cannot open \"%s\"", path); 2275 free(path); 2276 return (NULL); 2277 } 2278 } else { 2279 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2280 if (fd == -1) { 2281 _rtld_error("Cannot dup fd"); 2282 free(path); 2283 return (NULL); 2284 } 2285 } 2286 if (fstat(fd, &sb) == -1) { 2287 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2288 close(fd); 2289 free(path); 2290 return NULL; 2291 } 2292 TAILQ_FOREACH(obj, &obj_list, next) { 2293 if (obj->marker || obj->doomed) 2294 continue; 2295 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2296 break; 2297 } 2298 if (obj != NULL && name != NULL) { 2299 object_add_name(obj, name); 2300 free(path); 2301 close(fd); 2302 return obj; 2303 } 2304 if (flags & RTLD_LO_NOLOAD) { 2305 free(path); 2306 close(fd); 2307 return (NULL); 2308 } 2309 2310 /* First use of this object, so we must map it in */ 2311 obj = do_load_object(fd, name, path, &sb, flags); 2312 if (obj == NULL) 2313 free(path); 2314 close(fd); 2315 2316 return obj; 2317 } 2318 2319 static Obj_Entry * 2320 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2321 int flags) 2322 { 2323 Obj_Entry *obj; 2324 struct statfs fs; 2325 2326 /* 2327 * but first, make sure that environment variables haven't been 2328 * used to circumvent the noexec flag on a filesystem. 2329 */ 2330 if (dangerous_ld_env) { 2331 if (fstatfs(fd, &fs) != 0) { 2332 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2333 return NULL; 2334 } 2335 if (fs.f_flags & MNT_NOEXEC) { 2336 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2337 return NULL; 2338 } 2339 } 2340 dbg("loading \"%s\"", printable_path(path)); 2341 obj = map_object(fd, printable_path(path), sbp); 2342 if (obj == NULL) 2343 return NULL; 2344 2345 /* 2346 * If DT_SONAME is present in the object, digest_dynamic2 already 2347 * added it to the object names. 2348 */ 2349 if (name != NULL) 2350 object_add_name(obj, name); 2351 obj->path = path; 2352 digest_dynamic(obj, 0); 2353 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2354 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2355 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2356 RTLD_LO_DLOPEN) { 2357 dbg("refusing to load non-loadable \"%s\"", obj->path); 2358 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2359 munmap(obj->mapbase, obj->mapsize); 2360 obj_free(obj); 2361 return (NULL); 2362 } 2363 2364 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2365 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2366 obj_count++; 2367 obj_loads++; 2368 linkmap_add(obj); /* for GDB & dlinfo() */ 2369 max_stack_flags |= obj->stack_flags; 2370 2371 dbg(" %p .. %p: %s", obj->mapbase, 2372 obj->mapbase + obj->mapsize - 1, obj->path); 2373 if (obj->textrel) 2374 dbg(" WARNING: %s has impure text", obj->path); 2375 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2376 obj->path); 2377 2378 return obj; 2379 } 2380 2381 static Obj_Entry * 2382 obj_from_addr(const void *addr) 2383 { 2384 Obj_Entry *obj; 2385 2386 TAILQ_FOREACH(obj, &obj_list, next) { 2387 if (obj->marker) 2388 continue; 2389 if (addr < (void *) obj->mapbase) 2390 continue; 2391 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2392 return obj; 2393 } 2394 return NULL; 2395 } 2396 2397 static void 2398 preinit_main(void) 2399 { 2400 Elf_Addr *preinit_addr; 2401 int index; 2402 2403 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2404 if (preinit_addr == NULL) 2405 return; 2406 2407 for (index = 0; index < obj_main->preinit_array_num; index++) { 2408 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2409 dbg("calling preinit function for %s at %p", obj_main->path, 2410 (void *)preinit_addr[index]); 2411 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2412 0, 0, obj_main->path); 2413 call_init_pointer(obj_main, preinit_addr[index]); 2414 } 2415 } 2416 } 2417 2418 /* 2419 * Call the finalization functions for each of the objects in "list" 2420 * belonging to the DAG of "root" and referenced once. If NULL "root" 2421 * is specified, every finalization function will be called regardless 2422 * of the reference count and the list elements won't be freed. All of 2423 * the objects are expected to have non-NULL fini functions. 2424 */ 2425 static void 2426 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2427 { 2428 Objlist_Entry *elm; 2429 char *saved_msg; 2430 Elf_Addr *fini_addr; 2431 int index; 2432 2433 assert(root == NULL || root->refcount == 1); 2434 2435 if (root != NULL) 2436 root->doomed = true; 2437 2438 /* 2439 * Preserve the current error message since a fini function might 2440 * call into the dynamic linker and overwrite it. 2441 */ 2442 saved_msg = errmsg_save(); 2443 do { 2444 STAILQ_FOREACH(elm, list, link) { 2445 if (root != NULL && (elm->obj->refcount != 1 || 2446 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2447 continue; 2448 /* Remove object from fini list to prevent recursive invocation. */ 2449 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2450 /* Ensure that new references cannot be acquired. */ 2451 elm->obj->doomed = true; 2452 2453 hold_object(elm->obj); 2454 lock_release(rtld_bind_lock, lockstate); 2455 /* 2456 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2457 * When this happens, DT_FINI_ARRAY is processed first. 2458 */ 2459 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2460 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2461 for (index = elm->obj->fini_array_num - 1; index >= 0; 2462 index--) { 2463 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2464 dbg("calling fini function for %s at %p", 2465 elm->obj->path, (void *)fini_addr[index]); 2466 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2467 (void *)fini_addr[index], 0, 0, elm->obj->path); 2468 call_initfini_pointer(elm->obj, fini_addr[index]); 2469 } 2470 } 2471 } 2472 if (elm->obj->fini != (Elf_Addr)NULL) { 2473 dbg("calling fini function for %s at %p", elm->obj->path, 2474 (void *)elm->obj->fini); 2475 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2476 0, 0, elm->obj->path); 2477 call_initfini_pointer(elm->obj, elm->obj->fini); 2478 } 2479 wlock_acquire(rtld_bind_lock, lockstate); 2480 unhold_object(elm->obj); 2481 /* No need to free anything if process is going down. */ 2482 if (root != NULL) 2483 free(elm); 2484 /* 2485 * We must restart the list traversal after every fini call 2486 * because a dlclose() call from the fini function or from 2487 * another thread might have modified the reference counts. 2488 */ 2489 break; 2490 } 2491 } while (elm != NULL); 2492 errmsg_restore(saved_msg); 2493 } 2494 2495 /* 2496 * Call the initialization functions for each of the objects in 2497 * "list". All of the objects are expected to have non-NULL init 2498 * functions. 2499 */ 2500 static void 2501 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2502 { 2503 Objlist_Entry *elm; 2504 Obj_Entry *obj; 2505 char *saved_msg; 2506 Elf_Addr *init_addr; 2507 int index; 2508 2509 /* 2510 * Clean init_scanned flag so that objects can be rechecked and 2511 * possibly initialized earlier if any of vectors called below 2512 * cause the change by using dlopen. 2513 */ 2514 TAILQ_FOREACH(obj, &obj_list, next) { 2515 if (obj->marker) 2516 continue; 2517 obj->init_scanned = false; 2518 } 2519 2520 /* 2521 * Preserve the current error message since an init function might 2522 * call into the dynamic linker and overwrite it. 2523 */ 2524 saved_msg = errmsg_save(); 2525 STAILQ_FOREACH(elm, list, link) { 2526 if (elm->obj->init_done) /* Initialized early. */ 2527 continue; 2528 /* 2529 * Race: other thread might try to use this object before current 2530 * one completes the initialization. Not much can be done here 2531 * without better locking. 2532 */ 2533 elm->obj->init_done = true; 2534 hold_object(elm->obj); 2535 lock_release(rtld_bind_lock, lockstate); 2536 2537 /* 2538 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2539 * When this happens, DT_INIT is processed first. 2540 */ 2541 if (elm->obj->init != (Elf_Addr)NULL) { 2542 dbg("calling init function for %s at %p", elm->obj->path, 2543 (void *)elm->obj->init); 2544 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2545 0, 0, elm->obj->path); 2546 call_initfini_pointer(elm->obj, elm->obj->init); 2547 } 2548 init_addr = (Elf_Addr *)elm->obj->init_array; 2549 if (init_addr != NULL) { 2550 for (index = 0; index < elm->obj->init_array_num; index++) { 2551 if (init_addr[index] != 0 && init_addr[index] != 1) { 2552 dbg("calling init function for %s at %p", elm->obj->path, 2553 (void *)init_addr[index]); 2554 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2555 (void *)init_addr[index], 0, 0, elm->obj->path); 2556 call_init_pointer(elm->obj, init_addr[index]); 2557 } 2558 } 2559 } 2560 wlock_acquire(rtld_bind_lock, lockstate); 2561 unhold_object(elm->obj); 2562 } 2563 errmsg_restore(saved_msg); 2564 } 2565 2566 static void 2567 objlist_clear(Objlist *list) 2568 { 2569 Objlist_Entry *elm; 2570 2571 while (!STAILQ_EMPTY(list)) { 2572 elm = STAILQ_FIRST(list); 2573 STAILQ_REMOVE_HEAD(list, link); 2574 free(elm); 2575 } 2576 } 2577 2578 static Objlist_Entry * 2579 objlist_find(Objlist *list, const Obj_Entry *obj) 2580 { 2581 Objlist_Entry *elm; 2582 2583 STAILQ_FOREACH(elm, list, link) 2584 if (elm->obj == obj) 2585 return elm; 2586 return NULL; 2587 } 2588 2589 static void 2590 objlist_init(Objlist *list) 2591 { 2592 STAILQ_INIT(list); 2593 } 2594 2595 static void 2596 objlist_push_head(Objlist *list, Obj_Entry *obj) 2597 { 2598 Objlist_Entry *elm; 2599 2600 elm = NEW(Objlist_Entry); 2601 elm->obj = obj; 2602 STAILQ_INSERT_HEAD(list, elm, link); 2603 } 2604 2605 static void 2606 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2607 { 2608 Objlist_Entry *elm; 2609 2610 elm = NEW(Objlist_Entry); 2611 elm->obj = obj; 2612 STAILQ_INSERT_TAIL(list, elm, link); 2613 } 2614 2615 static void 2616 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2617 { 2618 Objlist_Entry *elm, *listelm; 2619 2620 STAILQ_FOREACH(listelm, list, link) { 2621 if (listelm->obj == listobj) 2622 break; 2623 } 2624 elm = NEW(Objlist_Entry); 2625 elm->obj = obj; 2626 if (listelm != NULL) 2627 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2628 else 2629 STAILQ_INSERT_TAIL(list, elm, link); 2630 } 2631 2632 static void 2633 objlist_remove(Objlist *list, Obj_Entry *obj) 2634 { 2635 Objlist_Entry *elm; 2636 2637 if ((elm = objlist_find(list, obj)) != NULL) { 2638 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2639 free(elm); 2640 } 2641 } 2642 2643 /* 2644 * Relocate dag rooted in the specified object. 2645 * Returns 0 on success, or -1 on failure. 2646 */ 2647 2648 static int 2649 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2650 int flags, RtldLockState *lockstate) 2651 { 2652 Objlist_Entry *elm; 2653 int error; 2654 2655 error = 0; 2656 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2657 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2658 lockstate); 2659 if (error == -1) 2660 break; 2661 } 2662 return (error); 2663 } 2664 2665 /* 2666 * Prepare for, or clean after, relocating an object marked with 2667 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2668 * segments are remapped read-write. After relocations are done, the 2669 * segment's permissions are returned back to the modes specified in 2670 * the phdrs. If any relocation happened, or always for wired 2671 * program, COW is triggered. 2672 */ 2673 static int 2674 reloc_textrel_prot(Obj_Entry *obj, bool before) 2675 { 2676 const Elf_Phdr *ph; 2677 void *base; 2678 size_t l, sz; 2679 int prot; 2680 2681 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2682 l--, ph++) { 2683 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2684 continue; 2685 base = obj->relocbase + trunc_page(ph->p_vaddr); 2686 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2687 trunc_page(ph->p_vaddr); 2688 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2689 if (mprotect(base, sz, prot) == -1) { 2690 _rtld_error("%s: Cannot write-%sable text segment: %s", 2691 obj->path, before ? "en" : "dis", 2692 rtld_strerror(errno)); 2693 return (-1); 2694 } 2695 } 2696 return (0); 2697 } 2698 2699 /* 2700 * Relocate single object. 2701 * Returns 0 on success, or -1 on failure. 2702 */ 2703 static int 2704 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2705 int flags, RtldLockState *lockstate) 2706 { 2707 2708 if (obj->relocated) 2709 return (0); 2710 obj->relocated = true; 2711 if (obj != rtldobj) 2712 dbg("relocating \"%s\"", obj->path); 2713 2714 if (obj->symtab == NULL || obj->strtab == NULL || 2715 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2716 _rtld_error("%s: Shared object has no run-time symbol table", 2717 obj->path); 2718 return (-1); 2719 } 2720 2721 /* There are relocations to the write-protected text segment. */ 2722 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2723 return (-1); 2724 2725 /* Process the non-PLT non-IFUNC relocations. */ 2726 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2727 return (-1); 2728 2729 /* Re-protected the text segment. */ 2730 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2731 return (-1); 2732 2733 /* Set the special PLT or GOT entries. */ 2734 init_pltgot(obj); 2735 2736 /* Process the PLT relocations. */ 2737 if (reloc_plt(obj) == -1) 2738 return (-1); 2739 /* Relocate the jump slots if we are doing immediate binding. */ 2740 if (obj->bind_now || bind_now) 2741 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2742 return (-1); 2743 2744 /* 2745 * Process the non-PLT IFUNC relocations. The relocations are 2746 * processed in two phases, because IFUNC resolvers may 2747 * reference other symbols, which must be readily processed 2748 * before resolvers are called. 2749 */ 2750 if (obj->non_plt_gnu_ifunc && 2751 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2752 return (-1); 2753 2754 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2755 return (-1); 2756 2757 /* 2758 * Set up the magic number and version in the Obj_Entry. These 2759 * were checked in the crt1.o from the original ElfKit, so we 2760 * set them for backward compatibility. 2761 */ 2762 obj->magic = RTLD_MAGIC; 2763 obj->version = RTLD_VERSION; 2764 2765 return (0); 2766 } 2767 2768 /* 2769 * Relocate newly-loaded shared objects. The argument is a pointer to 2770 * the Obj_Entry for the first such object. All objects from the first 2771 * to the end of the list of objects are relocated. Returns 0 on success, 2772 * or -1 on failure. 2773 */ 2774 static int 2775 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2776 int flags, RtldLockState *lockstate) 2777 { 2778 Obj_Entry *obj; 2779 int error; 2780 2781 for (error = 0, obj = first; obj != NULL; 2782 obj = TAILQ_NEXT(obj, next)) { 2783 if (obj->marker) 2784 continue; 2785 error = relocate_object(obj, bind_now, rtldobj, flags, 2786 lockstate); 2787 if (error == -1) 2788 break; 2789 } 2790 return (error); 2791 } 2792 2793 /* 2794 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2795 * referencing STT_GNU_IFUNC symbols is postponed till the other 2796 * relocations are done. The indirect functions specified as 2797 * ifunc are allowed to call other symbols, so we need to have 2798 * objects relocated before asking for resolution from indirects. 2799 * 2800 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2801 * instead of the usual lazy handling of PLT slots. It is 2802 * consistent with how GNU does it. 2803 */ 2804 static int 2805 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2806 RtldLockState *lockstate) 2807 { 2808 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2809 return (-1); 2810 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2811 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2812 return (-1); 2813 return (0); 2814 } 2815 2816 static int 2817 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2818 RtldLockState *lockstate) 2819 { 2820 Obj_Entry *obj; 2821 2822 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2823 if (obj->marker) 2824 continue; 2825 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2826 return (-1); 2827 } 2828 return (0); 2829 } 2830 2831 static int 2832 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2833 RtldLockState *lockstate) 2834 { 2835 Objlist_Entry *elm; 2836 2837 STAILQ_FOREACH(elm, list, link) { 2838 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2839 lockstate) == -1) 2840 return (-1); 2841 } 2842 return (0); 2843 } 2844 2845 /* 2846 * Cleanup procedure. It will be called (by the atexit mechanism) just 2847 * before the process exits. 2848 */ 2849 static void 2850 rtld_exit(void) 2851 { 2852 RtldLockState lockstate; 2853 2854 wlock_acquire(rtld_bind_lock, &lockstate); 2855 dbg("rtld_exit()"); 2856 objlist_call_fini(&list_fini, NULL, &lockstate); 2857 /* No need to remove the items from the list, since we are exiting. */ 2858 if (!libmap_disable) 2859 lm_fini(); 2860 lock_release(rtld_bind_lock, &lockstate); 2861 } 2862 2863 /* 2864 * Iterate over a search path, translate each element, and invoke the 2865 * callback on the result. 2866 */ 2867 static void * 2868 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2869 { 2870 const char *trans; 2871 if (path == NULL) 2872 return (NULL); 2873 2874 path += strspn(path, ":;"); 2875 while (*path != '\0') { 2876 size_t len; 2877 char *res; 2878 2879 len = strcspn(path, ":;"); 2880 trans = lm_findn(NULL, path, len); 2881 if (trans) 2882 res = callback(trans, strlen(trans), arg); 2883 else 2884 res = callback(path, len, arg); 2885 2886 if (res != NULL) 2887 return (res); 2888 2889 path += len; 2890 path += strspn(path, ":;"); 2891 } 2892 2893 return (NULL); 2894 } 2895 2896 struct try_library_args { 2897 const char *name; 2898 size_t namelen; 2899 char *buffer; 2900 size_t buflen; 2901 }; 2902 2903 static void * 2904 try_library_path(const char *dir, size_t dirlen, void *param) 2905 { 2906 struct try_library_args *arg; 2907 2908 arg = param; 2909 if (*dir == '/' || trust) { 2910 char *pathname; 2911 2912 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2913 return (NULL); 2914 2915 pathname = arg->buffer; 2916 strncpy(pathname, dir, dirlen); 2917 pathname[dirlen] = '/'; 2918 strcpy(pathname + dirlen + 1, arg->name); 2919 2920 dbg(" Trying \"%s\"", pathname); 2921 if (access(pathname, F_OK) == 0) { /* We found it */ 2922 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2923 strcpy(pathname, arg->buffer); 2924 return (pathname); 2925 } 2926 } 2927 return (NULL); 2928 } 2929 2930 static char * 2931 search_library_path(const char *name, const char *path) 2932 { 2933 char *p; 2934 struct try_library_args arg; 2935 2936 if (path == NULL) 2937 return NULL; 2938 2939 arg.name = name; 2940 arg.namelen = strlen(name); 2941 arg.buffer = xmalloc(PATH_MAX); 2942 arg.buflen = PATH_MAX; 2943 2944 p = path_enumerate(path, try_library_path, &arg); 2945 2946 free(arg.buffer); 2947 2948 return (p); 2949 } 2950 2951 2952 /* 2953 * Finds the library with the given name using the directory descriptors 2954 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2955 * 2956 * Returns a freshly-opened close-on-exec file descriptor for the library, 2957 * or -1 if the library cannot be found. 2958 */ 2959 static char * 2960 search_library_pathfds(const char *name, const char *path, int *fdp) 2961 { 2962 char *envcopy, *fdstr, *found, *last_token; 2963 size_t len; 2964 int dirfd, fd; 2965 2966 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2967 2968 /* Don't load from user-specified libdirs into setuid binaries. */ 2969 if (!trust) 2970 return (NULL); 2971 2972 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2973 if (path == NULL) 2974 return (NULL); 2975 2976 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2977 if (name[0] == '/') { 2978 dbg("Absolute path (%s) passed to %s", name, __func__); 2979 return (NULL); 2980 } 2981 2982 /* 2983 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2984 * copy of the path, as strtok_r rewrites separator tokens 2985 * with '\0'. 2986 */ 2987 found = NULL; 2988 envcopy = xstrdup(path); 2989 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2990 fdstr = strtok_r(NULL, ":", &last_token)) { 2991 dirfd = parse_libdir(fdstr); 2992 if (dirfd < 0) 2993 break; 2994 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2995 if (fd >= 0) { 2996 *fdp = fd; 2997 len = strlen(fdstr) + strlen(name) + 3; 2998 found = xmalloc(len); 2999 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3000 _rtld_error("error generating '%d/%s'", 3001 dirfd, name); 3002 rtld_die(); 3003 } 3004 dbg("open('%s') => %d", found, fd); 3005 break; 3006 } 3007 } 3008 free(envcopy); 3009 3010 return (found); 3011 } 3012 3013 3014 int 3015 dlclose(void *handle) 3016 { 3017 Obj_Entry *root; 3018 RtldLockState lockstate; 3019 3020 wlock_acquire(rtld_bind_lock, &lockstate); 3021 root = dlcheck(handle); 3022 if (root == NULL) { 3023 lock_release(rtld_bind_lock, &lockstate); 3024 return -1; 3025 } 3026 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3027 root->path); 3028 3029 /* Unreference the object and its dependencies. */ 3030 root->dl_refcount--; 3031 3032 if (root->refcount == 1) { 3033 /* 3034 * The object will be no longer referenced, so we must unload it. 3035 * First, call the fini functions. 3036 */ 3037 objlist_call_fini(&list_fini, root, &lockstate); 3038 3039 unref_dag(root); 3040 3041 /* Finish cleaning up the newly-unreferenced objects. */ 3042 GDB_STATE(RT_DELETE,&root->linkmap); 3043 unload_object(root); 3044 GDB_STATE(RT_CONSISTENT,NULL); 3045 } else 3046 unref_dag(root); 3047 3048 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3049 lock_release(rtld_bind_lock, &lockstate); 3050 return 0; 3051 } 3052 3053 char * 3054 dlerror(void) 3055 { 3056 char *msg = error_message; 3057 error_message = NULL; 3058 return msg; 3059 } 3060 3061 /* 3062 * This function is deprecated and has no effect. 3063 */ 3064 void 3065 dllockinit(void *context, 3066 void *(*lock_create)(void *context), 3067 void (*rlock_acquire)(void *lock), 3068 void (*wlock_acquire)(void *lock), 3069 void (*lock_release)(void *lock), 3070 void (*lock_destroy)(void *lock), 3071 void (*context_destroy)(void *context)) 3072 { 3073 static void *cur_context; 3074 static void (*cur_context_destroy)(void *); 3075 3076 /* Just destroy the context from the previous call, if necessary. */ 3077 if (cur_context_destroy != NULL) 3078 cur_context_destroy(cur_context); 3079 cur_context = context; 3080 cur_context_destroy = context_destroy; 3081 } 3082 3083 void * 3084 dlopen(const char *name, int mode) 3085 { 3086 3087 return (rtld_dlopen(name, -1, mode)); 3088 } 3089 3090 void * 3091 fdlopen(int fd, int mode) 3092 { 3093 3094 return (rtld_dlopen(NULL, fd, mode)); 3095 } 3096 3097 static void * 3098 rtld_dlopen(const char *name, int fd, int mode) 3099 { 3100 RtldLockState lockstate; 3101 int lo_flags; 3102 3103 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3104 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3105 if (ld_tracing != NULL) { 3106 rlock_acquire(rtld_bind_lock, &lockstate); 3107 if (sigsetjmp(lockstate.env, 0) != 0) 3108 lock_upgrade(rtld_bind_lock, &lockstate); 3109 environ = (char **)*get_program_var_addr("environ", &lockstate); 3110 lock_release(rtld_bind_lock, &lockstate); 3111 } 3112 lo_flags = RTLD_LO_DLOPEN; 3113 if (mode & RTLD_NODELETE) 3114 lo_flags |= RTLD_LO_NODELETE; 3115 if (mode & RTLD_NOLOAD) 3116 lo_flags |= RTLD_LO_NOLOAD; 3117 if (ld_tracing != NULL) 3118 lo_flags |= RTLD_LO_TRACE; 3119 3120 return (dlopen_object(name, fd, obj_main, lo_flags, 3121 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3122 } 3123 3124 static void 3125 dlopen_cleanup(Obj_Entry *obj) 3126 { 3127 3128 obj->dl_refcount--; 3129 unref_dag(obj); 3130 if (obj->refcount == 0) 3131 unload_object(obj); 3132 } 3133 3134 static Obj_Entry * 3135 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3136 int mode, RtldLockState *lockstate) 3137 { 3138 Obj_Entry *old_obj_tail; 3139 Obj_Entry *obj; 3140 Objlist initlist; 3141 RtldLockState mlockstate; 3142 int result; 3143 3144 objlist_init(&initlist); 3145 3146 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3147 wlock_acquire(rtld_bind_lock, &mlockstate); 3148 lockstate = &mlockstate; 3149 } 3150 GDB_STATE(RT_ADD,NULL); 3151 3152 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3153 obj = NULL; 3154 if (name == NULL && fd == -1) { 3155 obj = obj_main; 3156 obj->refcount++; 3157 } else { 3158 obj = load_object(name, fd, refobj, lo_flags); 3159 } 3160 3161 if (obj) { 3162 obj->dl_refcount++; 3163 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3164 objlist_push_tail(&list_global, obj); 3165 if (globallist_next(old_obj_tail) != NULL) { 3166 /* We loaded something new. */ 3167 assert(globallist_next(old_obj_tail) == obj); 3168 result = load_needed_objects(obj, 3169 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3170 init_dag(obj); 3171 ref_dag(obj); 3172 if (result != -1) 3173 result = rtld_verify_versions(&obj->dagmembers); 3174 if (result != -1 && ld_tracing) 3175 goto trace; 3176 if (result == -1 || relocate_object_dag(obj, 3177 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3178 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3179 lockstate) == -1) { 3180 dlopen_cleanup(obj); 3181 obj = NULL; 3182 } else if (lo_flags & RTLD_LO_EARLY) { 3183 /* 3184 * Do not call the init functions for early loaded 3185 * filtees. The image is still not initialized enough 3186 * for them to work. 3187 * 3188 * Our object is found by the global object list and 3189 * will be ordered among all init calls done right 3190 * before transferring control to main. 3191 */ 3192 } else { 3193 /* Make list of init functions to call. */ 3194 initlist_add_objects(obj, obj, &initlist); 3195 } 3196 /* 3197 * Process all no_delete or global objects here, given 3198 * them own DAGs to prevent their dependencies from being 3199 * unloaded. This has to be done after we have loaded all 3200 * of the dependencies, so that we do not miss any. 3201 */ 3202 if (obj != NULL) 3203 process_z(obj); 3204 } else { 3205 /* 3206 * Bump the reference counts for objects on this DAG. If 3207 * this is the first dlopen() call for the object that was 3208 * already loaded as a dependency, initialize the dag 3209 * starting at it. 3210 */ 3211 init_dag(obj); 3212 ref_dag(obj); 3213 3214 if ((lo_flags & RTLD_LO_TRACE) != 0) 3215 goto trace; 3216 } 3217 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3218 obj->z_nodelete) && !obj->ref_nodel) { 3219 dbg("obj %s nodelete", obj->path); 3220 ref_dag(obj); 3221 obj->z_nodelete = obj->ref_nodel = true; 3222 } 3223 } 3224 3225 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3226 name); 3227 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3228 3229 if (!(lo_flags & RTLD_LO_EARLY)) { 3230 map_stacks_exec(lockstate); 3231 } 3232 3233 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3234 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3235 lockstate) == -1) { 3236 objlist_clear(&initlist); 3237 dlopen_cleanup(obj); 3238 if (lockstate == &mlockstate) 3239 lock_release(rtld_bind_lock, lockstate); 3240 return (NULL); 3241 } 3242 3243 if (!(lo_flags & RTLD_LO_EARLY)) { 3244 /* Call the init functions. */ 3245 objlist_call_init(&initlist, lockstate); 3246 } 3247 objlist_clear(&initlist); 3248 if (lockstate == &mlockstate) 3249 lock_release(rtld_bind_lock, lockstate); 3250 return obj; 3251 trace: 3252 trace_loaded_objects(obj); 3253 if (lockstate == &mlockstate) 3254 lock_release(rtld_bind_lock, lockstate); 3255 exit(0); 3256 } 3257 3258 static void * 3259 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3260 int flags) 3261 { 3262 DoneList donelist; 3263 const Obj_Entry *obj, *defobj; 3264 const Elf_Sym *def; 3265 SymLook req; 3266 RtldLockState lockstate; 3267 tls_index ti; 3268 void *sym; 3269 int res; 3270 3271 def = NULL; 3272 defobj = NULL; 3273 symlook_init(&req, name); 3274 req.ventry = ve; 3275 req.flags = flags | SYMLOOK_IN_PLT; 3276 req.lockstate = &lockstate; 3277 3278 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3279 rlock_acquire(rtld_bind_lock, &lockstate); 3280 if (sigsetjmp(lockstate.env, 0) != 0) 3281 lock_upgrade(rtld_bind_lock, &lockstate); 3282 if (handle == NULL || handle == RTLD_NEXT || 3283 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3284 3285 if ((obj = obj_from_addr(retaddr)) == NULL) { 3286 _rtld_error("Cannot determine caller's shared object"); 3287 lock_release(rtld_bind_lock, &lockstate); 3288 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3289 return NULL; 3290 } 3291 if (handle == NULL) { /* Just the caller's shared object. */ 3292 res = symlook_obj(&req, obj); 3293 if (res == 0) { 3294 def = req.sym_out; 3295 defobj = req.defobj_out; 3296 } 3297 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3298 handle == RTLD_SELF) { /* ... caller included */ 3299 if (handle == RTLD_NEXT) 3300 obj = globallist_next(obj); 3301 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3302 if (obj->marker) 3303 continue; 3304 res = symlook_obj(&req, obj); 3305 if (res == 0) { 3306 if (def == NULL || 3307 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3308 def = req.sym_out; 3309 defobj = req.defobj_out; 3310 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3311 break; 3312 } 3313 } 3314 } 3315 /* 3316 * Search the dynamic linker itself, and possibly resolve the 3317 * symbol from there. This is how the application links to 3318 * dynamic linker services such as dlopen. 3319 */ 3320 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3321 res = symlook_obj(&req, &obj_rtld); 3322 if (res == 0) { 3323 def = req.sym_out; 3324 defobj = req.defobj_out; 3325 } 3326 } 3327 } else { 3328 assert(handle == RTLD_DEFAULT); 3329 res = symlook_default(&req, obj); 3330 if (res == 0) { 3331 defobj = req.defobj_out; 3332 def = req.sym_out; 3333 } 3334 } 3335 } else { 3336 if ((obj = dlcheck(handle)) == NULL) { 3337 lock_release(rtld_bind_lock, &lockstate); 3338 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3339 return NULL; 3340 } 3341 3342 donelist_init(&donelist); 3343 if (obj->mainprog) { 3344 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3345 res = symlook_global(&req, &donelist); 3346 if (res == 0) { 3347 def = req.sym_out; 3348 defobj = req.defobj_out; 3349 } 3350 /* 3351 * Search the dynamic linker itself, and possibly resolve the 3352 * symbol from there. This is how the application links to 3353 * dynamic linker services such as dlopen. 3354 */ 3355 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3356 res = symlook_obj(&req, &obj_rtld); 3357 if (res == 0) { 3358 def = req.sym_out; 3359 defobj = req.defobj_out; 3360 } 3361 } 3362 } 3363 else { 3364 /* Search the whole DAG rooted at the given object. */ 3365 res = symlook_list(&req, &obj->dagmembers, &donelist); 3366 if (res == 0) { 3367 def = req.sym_out; 3368 defobj = req.defobj_out; 3369 } 3370 } 3371 } 3372 3373 if (def != NULL) { 3374 lock_release(rtld_bind_lock, &lockstate); 3375 3376 /* 3377 * The value required by the caller is derived from the value 3378 * of the symbol. this is simply the relocated value of the 3379 * symbol. 3380 */ 3381 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3382 sym = make_function_pointer(def, defobj); 3383 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3384 sym = rtld_resolve_ifunc(defobj, def); 3385 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3386 ti.ti_module = defobj->tlsindex; 3387 ti.ti_offset = def->st_value; 3388 sym = __tls_get_addr(&ti); 3389 } else 3390 sym = defobj->relocbase + def->st_value; 3391 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3392 return (sym); 3393 } 3394 3395 _rtld_error("Undefined symbol \"%s\"", name); 3396 lock_release(rtld_bind_lock, &lockstate); 3397 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3398 return NULL; 3399 } 3400 3401 void * 3402 dlsym(void *handle, const char *name) 3403 { 3404 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3405 SYMLOOK_DLSYM); 3406 } 3407 3408 dlfunc_t 3409 dlfunc(void *handle, const char *name) 3410 { 3411 union { 3412 void *d; 3413 dlfunc_t f; 3414 } rv; 3415 3416 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3417 SYMLOOK_DLSYM); 3418 return (rv.f); 3419 } 3420 3421 void * 3422 dlvsym(void *handle, const char *name, const char *version) 3423 { 3424 Ver_Entry ventry; 3425 3426 ventry.name = version; 3427 ventry.file = NULL; 3428 ventry.hash = elf_hash(version); 3429 ventry.flags= 0; 3430 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3431 SYMLOOK_DLSYM); 3432 } 3433 3434 int 3435 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3436 { 3437 const Obj_Entry *obj; 3438 RtldLockState lockstate; 3439 3440 rlock_acquire(rtld_bind_lock, &lockstate); 3441 obj = obj_from_addr(addr); 3442 if (obj == NULL) { 3443 _rtld_error("No shared object contains address"); 3444 lock_release(rtld_bind_lock, &lockstate); 3445 return (0); 3446 } 3447 rtld_fill_dl_phdr_info(obj, phdr_info); 3448 lock_release(rtld_bind_lock, &lockstate); 3449 return (1); 3450 } 3451 3452 int 3453 dladdr(const void *addr, Dl_info *info) 3454 { 3455 const Obj_Entry *obj; 3456 const Elf_Sym *def; 3457 void *symbol_addr; 3458 unsigned long symoffset; 3459 RtldLockState lockstate; 3460 3461 rlock_acquire(rtld_bind_lock, &lockstate); 3462 obj = obj_from_addr(addr); 3463 if (obj == NULL) { 3464 _rtld_error("No shared object contains address"); 3465 lock_release(rtld_bind_lock, &lockstate); 3466 return 0; 3467 } 3468 info->dli_fname = obj->path; 3469 info->dli_fbase = obj->mapbase; 3470 info->dli_saddr = (void *)0; 3471 info->dli_sname = NULL; 3472 3473 /* 3474 * Walk the symbol list looking for the symbol whose address is 3475 * closest to the address sent in. 3476 */ 3477 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3478 def = obj->symtab + symoffset; 3479 3480 /* 3481 * For skip the symbol if st_shndx is either SHN_UNDEF or 3482 * SHN_COMMON. 3483 */ 3484 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3485 continue; 3486 3487 /* 3488 * If the symbol is greater than the specified address, or if it 3489 * is further away from addr than the current nearest symbol, 3490 * then reject it. 3491 */ 3492 symbol_addr = obj->relocbase + def->st_value; 3493 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3494 continue; 3495 3496 /* Update our idea of the nearest symbol. */ 3497 info->dli_sname = obj->strtab + def->st_name; 3498 info->dli_saddr = symbol_addr; 3499 3500 /* Exact match? */ 3501 if (info->dli_saddr == addr) 3502 break; 3503 } 3504 lock_release(rtld_bind_lock, &lockstate); 3505 return 1; 3506 } 3507 3508 int 3509 dlinfo(void *handle, int request, void *p) 3510 { 3511 const Obj_Entry *obj; 3512 RtldLockState lockstate; 3513 int error; 3514 3515 rlock_acquire(rtld_bind_lock, &lockstate); 3516 3517 if (handle == NULL || handle == RTLD_SELF) { 3518 void *retaddr; 3519 3520 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3521 if ((obj = obj_from_addr(retaddr)) == NULL) 3522 _rtld_error("Cannot determine caller's shared object"); 3523 } else 3524 obj = dlcheck(handle); 3525 3526 if (obj == NULL) { 3527 lock_release(rtld_bind_lock, &lockstate); 3528 return (-1); 3529 } 3530 3531 error = 0; 3532 switch (request) { 3533 case RTLD_DI_LINKMAP: 3534 *((struct link_map const **)p) = &obj->linkmap; 3535 break; 3536 case RTLD_DI_ORIGIN: 3537 error = rtld_dirname(obj->path, p); 3538 break; 3539 3540 case RTLD_DI_SERINFOSIZE: 3541 case RTLD_DI_SERINFO: 3542 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3543 break; 3544 3545 default: 3546 _rtld_error("Invalid request %d passed to dlinfo()", request); 3547 error = -1; 3548 } 3549 3550 lock_release(rtld_bind_lock, &lockstate); 3551 3552 return (error); 3553 } 3554 3555 static void 3556 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3557 { 3558 3559 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3560 phdr_info->dlpi_name = obj->path; 3561 phdr_info->dlpi_phdr = obj->phdr; 3562 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3563 phdr_info->dlpi_tls_modid = obj->tlsindex; 3564 phdr_info->dlpi_tls_data = obj->tlsinit; 3565 phdr_info->dlpi_adds = obj_loads; 3566 phdr_info->dlpi_subs = obj_loads - obj_count; 3567 } 3568 3569 int 3570 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3571 { 3572 struct dl_phdr_info phdr_info; 3573 Obj_Entry *obj, marker; 3574 RtldLockState bind_lockstate, phdr_lockstate; 3575 int error; 3576 3577 init_marker(&marker); 3578 error = 0; 3579 3580 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3581 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3582 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3583 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3584 rtld_fill_dl_phdr_info(obj, &phdr_info); 3585 hold_object(obj); 3586 lock_release(rtld_bind_lock, &bind_lockstate); 3587 3588 error = callback(&phdr_info, sizeof phdr_info, param); 3589 3590 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3591 unhold_object(obj); 3592 obj = globallist_next(&marker); 3593 TAILQ_REMOVE(&obj_list, &marker, next); 3594 if (error != 0) { 3595 lock_release(rtld_bind_lock, &bind_lockstate); 3596 lock_release(rtld_phdr_lock, &phdr_lockstate); 3597 return (error); 3598 } 3599 } 3600 3601 if (error == 0) { 3602 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3603 lock_release(rtld_bind_lock, &bind_lockstate); 3604 error = callback(&phdr_info, sizeof(phdr_info), param); 3605 } 3606 lock_release(rtld_phdr_lock, &phdr_lockstate); 3607 return (error); 3608 } 3609 3610 static void * 3611 fill_search_info(const char *dir, size_t dirlen, void *param) 3612 { 3613 struct fill_search_info_args *arg; 3614 3615 arg = param; 3616 3617 if (arg->request == RTLD_DI_SERINFOSIZE) { 3618 arg->serinfo->dls_cnt ++; 3619 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3620 } else { 3621 struct dl_serpath *s_entry; 3622 3623 s_entry = arg->serpath; 3624 s_entry->dls_name = arg->strspace; 3625 s_entry->dls_flags = arg->flags; 3626 3627 strncpy(arg->strspace, dir, dirlen); 3628 arg->strspace[dirlen] = '\0'; 3629 3630 arg->strspace += dirlen + 1; 3631 arg->serpath++; 3632 } 3633 3634 return (NULL); 3635 } 3636 3637 static int 3638 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3639 { 3640 struct dl_serinfo _info; 3641 struct fill_search_info_args args; 3642 3643 args.request = RTLD_DI_SERINFOSIZE; 3644 args.serinfo = &_info; 3645 3646 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3647 _info.dls_cnt = 0; 3648 3649 path_enumerate(obj->rpath, fill_search_info, &args); 3650 path_enumerate(ld_library_path, fill_search_info, &args); 3651 path_enumerate(obj->runpath, fill_search_info, &args); 3652 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3653 if (!obj->z_nodeflib) 3654 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3655 3656 3657 if (request == RTLD_DI_SERINFOSIZE) { 3658 info->dls_size = _info.dls_size; 3659 info->dls_cnt = _info.dls_cnt; 3660 return (0); 3661 } 3662 3663 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3664 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3665 return (-1); 3666 } 3667 3668 args.request = RTLD_DI_SERINFO; 3669 args.serinfo = info; 3670 args.serpath = &info->dls_serpath[0]; 3671 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3672 3673 args.flags = LA_SER_RUNPATH; 3674 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3675 return (-1); 3676 3677 args.flags = LA_SER_LIBPATH; 3678 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3679 return (-1); 3680 3681 args.flags = LA_SER_RUNPATH; 3682 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3683 return (-1); 3684 3685 args.flags = LA_SER_CONFIG; 3686 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3687 != NULL) 3688 return (-1); 3689 3690 args.flags = LA_SER_DEFAULT; 3691 if (!obj->z_nodeflib && 3692 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3693 return (-1); 3694 return (0); 3695 } 3696 3697 static int 3698 rtld_dirname(const char *path, char *bname) 3699 { 3700 const char *endp; 3701 3702 /* Empty or NULL string gets treated as "." */ 3703 if (path == NULL || *path == '\0') { 3704 bname[0] = '.'; 3705 bname[1] = '\0'; 3706 return (0); 3707 } 3708 3709 /* Strip trailing slashes */ 3710 endp = path + strlen(path) - 1; 3711 while (endp > path && *endp == '/') 3712 endp--; 3713 3714 /* Find the start of the dir */ 3715 while (endp > path && *endp != '/') 3716 endp--; 3717 3718 /* Either the dir is "/" or there are no slashes */ 3719 if (endp == path) { 3720 bname[0] = *endp == '/' ? '/' : '.'; 3721 bname[1] = '\0'; 3722 return (0); 3723 } else { 3724 do { 3725 endp--; 3726 } while (endp > path && *endp == '/'); 3727 } 3728 3729 if (endp - path + 2 > PATH_MAX) 3730 { 3731 _rtld_error("Filename is too long: %s", path); 3732 return(-1); 3733 } 3734 3735 strncpy(bname, path, endp - path + 1); 3736 bname[endp - path + 1] = '\0'; 3737 return (0); 3738 } 3739 3740 static int 3741 rtld_dirname_abs(const char *path, char *base) 3742 { 3743 char *last; 3744 3745 if (realpath(path, base) == NULL) 3746 return (-1); 3747 dbg("%s -> %s", path, base); 3748 last = strrchr(base, '/'); 3749 if (last == NULL) 3750 return (-1); 3751 if (last != base) 3752 *last = '\0'; 3753 return (0); 3754 } 3755 3756 static void 3757 linkmap_add(Obj_Entry *obj) 3758 { 3759 struct link_map *l = &obj->linkmap; 3760 struct link_map *prev; 3761 3762 obj->linkmap.l_name = obj->path; 3763 obj->linkmap.l_addr = obj->mapbase; 3764 obj->linkmap.l_ld = obj->dynamic; 3765 #ifdef __mips__ 3766 /* GDB needs load offset on MIPS to use the symbols */ 3767 obj->linkmap.l_offs = obj->relocbase; 3768 #endif 3769 3770 if (r_debug.r_map == NULL) { 3771 r_debug.r_map = l; 3772 return; 3773 } 3774 3775 /* 3776 * Scan to the end of the list, but not past the entry for the 3777 * dynamic linker, which we want to keep at the very end. 3778 */ 3779 for (prev = r_debug.r_map; 3780 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3781 prev = prev->l_next) 3782 ; 3783 3784 /* Link in the new entry. */ 3785 l->l_prev = prev; 3786 l->l_next = prev->l_next; 3787 if (l->l_next != NULL) 3788 l->l_next->l_prev = l; 3789 prev->l_next = l; 3790 } 3791 3792 static void 3793 linkmap_delete(Obj_Entry *obj) 3794 { 3795 struct link_map *l = &obj->linkmap; 3796 3797 if (l->l_prev == NULL) { 3798 if ((r_debug.r_map = l->l_next) != NULL) 3799 l->l_next->l_prev = NULL; 3800 return; 3801 } 3802 3803 if ((l->l_prev->l_next = l->l_next) != NULL) 3804 l->l_next->l_prev = l->l_prev; 3805 } 3806 3807 /* 3808 * Function for the debugger to set a breakpoint on to gain control. 3809 * 3810 * The two parameters allow the debugger to easily find and determine 3811 * what the runtime loader is doing and to whom it is doing it. 3812 * 3813 * When the loadhook trap is hit (r_debug_state, set at program 3814 * initialization), the arguments can be found on the stack: 3815 * 3816 * +8 struct link_map *m 3817 * +4 struct r_debug *rd 3818 * +0 RetAddr 3819 */ 3820 void 3821 r_debug_state(struct r_debug* rd, struct link_map *m) 3822 { 3823 /* 3824 * The following is a hack to force the compiler to emit calls to 3825 * this function, even when optimizing. If the function is empty, 3826 * the compiler is not obliged to emit any code for calls to it, 3827 * even when marked __noinline. However, gdb depends on those 3828 * calls being made. 3829 */ 3830 __compiler_membar(); 3831 } 3832 3833 /* 3834 * A function called after init routines have completed. This can be used to 3835 * break before a program's entry routine is called, and can be used when 3836 * main is not available in the symbol table. 3837 */ 3838 void 3839 _r_debug_postinit(struct link_map *m) 3840 { 3841 3842 /* See r_debug_state(). */ 3843 __compiler_membar(); 3844 } 3845 3846 static void 3847 release_object(Obj_Entry *obj) 3848 { 3849 3850 if (obj->holdcount > 0) { 3851 obj->unholdfree = true; 3852 return; 3853 } 3854 munmap(obj->mapbase, obj->mapsize); 3855 linkmap_delete(obj); 3856 obj_free(obj); 3857 } 3858 3859 /* 3860 * Get address of the pointer variable in the main program. 3861 * Prefer non-weak symbol over the weak one. 3862 */ 3863 static const void ** 3864 get_program_var_addr(const char *name, RtldLockState *lockstate) 3865 { 3866 SymLook req; 3867 DoneList donelist; 3868 3869 symlook_init(&req, name); 3870 req.lockstate = lockstate; 3871 donelist_init(&donelist); 3872 if (symlook_global(&req, &donelist) != 0) 3873 return (NULL); 3874 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3875 return ((const void **)make_function_pointer(req.sym_out, 3876 req.defobj_out)); 3877 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3878 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3879 else 3880 return ((const void **)(req.defobj_out->relocbase + 3881 req.sym_out->st_value)); 3882 } 3883 3884 /* 3885 * Set a pointer variable in the main program to the given value. This 3886 * is used to set key variables such as "environ" before any of the 3887 * init functions are called. 3888 */ 3889 static void 3890 set_program_var(const char *name, const void *value) 3891 { 3892 const void **addr; 3893 3894 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3895 dbg("\"%s\": *%p <-- %p", name, addr, value); 3896 *addr = value; 3897 } 3898 } 3899 3900 /* 3901 * Search the global objects, including dependencies and main object, 3902 * for the given symbol. 3903 */ 3904 static int 3905 symlook_global(SymLook *req, DoneList *donelist) 3906 { 3907 SymLook req1; 3908 const Objlist_Entry *elm; 3909 int res; 3910 3911 symlook_init_from_req(&req1, req); 3912 3913 /* Search all objects loaded at program start up. */ 3914 if (req->defobj_out == NULL || 3915 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3916 res = symlook_list(&req1, &list_main, donelist); 3917 if (res == 0 && (req->defobj_out == NULL || 3918 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3919 req->sym_out = req1.sym_out; 3920 req->defobj_out = req1.defobj_out; 3921 assert(req->defobj_out != NULL); 3922 } 3923 } 3924 3925 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3926 STAILQ_FOREACH(elm, &list_global, link) { 3927 if (req->defobj_out != NULL && 3928 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3929 break; 3930 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3931 if (res == 0 && (req->defobj_out == NULL || 3932 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3933 req->sym_out = req1.sym_out; 3934 req->defobj_out = req1.defobj_out; 3935 assert(req->defobj_out != NULL); 3936 } 3937 } 3938 3939 return (req->sym_out != NULL ? 0 : ESRCH); 3940 } 3941 3942 /* 3943 * Given a symbol name in a referencing object, find the corresponding 3944 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3945 * no definition was found. Returns a pointer to the Obj_Entry of the 3946 * defining object via the reference parameter DEFOBJ_OUT. 3947 */ 3948 static int 3949 symlook_default(SymLook *req, const Obj_Entry *refobj) 3950 { 3951 DoneList donelist; 3952 const Objlist_Entry *elm; 3953 SymLook req1; 3954 int res; 3955 3956 donelist_init(&donelist); 3957 symlook_init_from_req(&req1, req); 3958 3959 /* Look first in the referencing object if linked symbolically. */ 3960 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3961 res = symlook_obj(&req1, refobj); 3962 if (res == 0) { 3963 req->sym_out = req1.sym_out; 3964 req->defobj_out = req1.defobj_out; 3965 assert(req->defobj_out != NULL); 3966 } 3967 } 3968 3969 symlook_global(req, &donelist); 3970 3971 /* Search all dlopened DAGs containing the referencing object. */ 3972 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3973 if (req->sym_out != NULL && 3974 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3975 break; 3976 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3977 if (res == 0 && (req->sym_out == NULL || 3978 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3979 req->sym_out = req1.sym_out; 3980 req->defobj_out = req1.defobj_out; 3981 assert(req->defobj_out != NULL); 3982 } 3983 } 3984 3985 /* 3986 * Search the dynamic linker itself, and possibly resolve the 3987 * symbol from there. This is how the application links to 3988 * dynamic linker services such as dlopen. 3989 */ 3990 if (req->sym_out == NULL || 3991 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3992 res = symlook_obj(&req1, &obj_rtld); 3993 if (res == 0) { 3994 req->sym_out = req1.sym_out; 3995 req->defobj_out = req1.defobj_out; 3996 assert(req->defobj_out != NULL); 3997 } 3998 } 3999 4000 return (req->sym_out != NULL ? 0 : ESRCH); 4001 } 4002 4003 static int 4004 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4005 { 4006 const Elf_Sym *def; 4007 const Obj_Entry *defobj; 4008 const Objlist_Entry *elm; 4009 SymLook req1; 4010 int res; 4011 4012 def = NULL; 4013 defobj = NULL; 4014 STAILQ_FOREACH(elm, objlist, link) { 4015 if (donelist_check(dlp, elm->obj)) 4016 continue; 4017 symlook_init_from_req(&req1, req); 4018 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4019 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4020 def = req1.sym_out; 4021 defobj = req1.defobj_out; 4022 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4023 break; 4024 } 4025 } 4026 } 4027 if (def != NULL) { 4028 req->sym_out = def; 4029 req->defobj_out = defobj; 4030 return (0); 4031 } 4032 return (ESRCH); 4033 } 4034 4035 /* 4036 * Search the chain of DAGS cointed to by the given Needed_Entry 4037 * for a symbol of the given name. Each DAG is scanned completely 4038 * before advancing to the next one. Returns a pointer to the symbol, 4039 * or NULL if no definition was found. 4040 */ 4041 static int 4042 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4043 { 4044 const Elf_Sym *def; 4045 const Needed_Entry *n; 4046 const Obj_Entry *defobj; 4047 SymLook req1; 4048 int res; 4049 4050 def = NULL; 4051 defobj = NULL; 4052 symlook_init_from_req(&req1, req); 4053 for (n = needed; n != NULL; n = n->next) { 4054 if (n->obj == NULL || 4055 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4056 continue; 4057 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4058 def = req1.sym_out; 4059 defobj = req1.defobj_out; 4060 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4061 break; 4062 } 4063 } 4064 if (def != NULL) { 4065 req->sym_out = def; 4066 req->defobj_out = defobj; 4067 return (0); 4068 } 4069 return (ESRCH); 4070 } 4071 4072 /* 4073 * Search the symbol table of a single shared object for a symbol of 4074 * the given name and version, if requested. Returns a pointer to the 4075 * symbol, or NULL if no definition was found. If the object is 4076 * filter, return filtered symbol from filtee. 4077 * 4078 * The symbol's hash value is passed in for efficiency reasons; that 4079 * eliminates many recomputations of the hash value. 4080 */ 4081 int 4082 symlook_obj(SymLook *req, const Obj_Entry *obj) 4083 { 4084 DoneList donelist; 4085 SymLook req1; 4086 int flags, res, mres; 4087 4088 /* 4089 * If there is at least one valid hash at this point, we prefer to 4090 * use the faster GNU version if available. 4091 */ 4092 if (obj->valid_hash_gnu) 4093 mres = symlook_obj1_gnu(req, obj); 4094 else if (obj->valid_hash_sysv) 4095 mres = symlook_obj1_sysv(req, obj); 4096 else 4097 return (EINVAL); 4098 4099 if (mres == 0) { 4100 if (obj->needed_filtees != NULL) { 4101 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4102 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4103 donelist_init(&donelist); 4104 symlook_init_from_req(&req1, req); 4105 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4106 if (res == 0) { 4107 req->sym_out = req1.sym_out; 4108 req->defobj_out = req1.defobj_out; 4109 } 4110 return (res); 4111 } 4112 if (obj->needed_aux_filtees != NULL) { 4113 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4114 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4115 donelist_init(&donelist); 4116 symlook_init_from_req(&req1, req); 4117 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4118 if (res == 0) { 4119 req->sym_out = req1.sym_out; 4120 req->defobj_out = req1.defobj_out; 4121 return (res); 4122 } 4123 } 4124 } 4125 return (mres); 4126 } 4127 4128 /* Symbol match routine common to both hash functions */ 4129 static bool 4130 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4131 const unsigned long symnum) 4132 { 4133 Elf_Versym verndx; 4134 const Elf_Sym *symp; 4135 const char *strp; 4136 4137 symp = obj->symtab + symnum; 4138 strp = obj->strtab + symp->st_name; 4139 4140 switch (ELF_ST_TYPE(symp->st_info)) { 4141 case STT_FUNC: 4142 case STT_NOTYPE: 4143 case STT_OBJECT: 4144 case STT_COMMON: 4145 case STT_GNU_IFUNC: 4146 if (symp->st_value == 0) 4147 return (false); 4148 /* fallthrough */ 4149 case STT_TLS: 4150 if (symp->st_shndx != SHN_UNDEF) 4151 break; 4152 #ifndef __mips__ 4153 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4154 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4155 break; 4156 /* fallthrough */ 4157 #endif 4158 default: 4159 return (false); 4160 } 4161 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4162 return (false); 4163 4164 if (req->ventry == NULL) { 4165 if (obj->versyms != NULL) { 4166 verndx = VER_NDX(obj->versyms[symnum]); 4167 if (verndx > obj->vernum) { 4168 _rtld_error( 4169 "%s: symbol %s references wrong version %d", 4170 obj->path, obj->strtab + symnum, verndx); 4171 return (false); 4172 } 4173 /* 4174 * If we are not called from dlsym (i.e. this 4175 * is a normal relocation from unversioned 4176 * binary), accept the symbol immediately if 4177 * it happens to have first version after this 4178 * shared object became versioned. Otherwise, 4179 * if symbol is versioned and not hidden, 4180 * remember it. If it is the only symbol with 4181 * this name exported by the shared object, it 4182 * will be returned as a match by the calling 4183 * function. If symbol is global (verndx < 2) 4184 * accept it unconditionally. 4185 */ 4186 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4187 verndx == VER_NDX_GIVEN) { 4188 result->sym_out = symp; 4189 return (true); 4190 } 4191 else if (verndx >= VER_NDX_GIVEN) { 4192 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4193 == 0) { 4194 if (result->vsymp == NULL) 4195 result->vsymp = symp; 4196 result->vcount++; 4197 } 4198 return (false); 4199 } 4200 } 4201 result->sym_out = symp; 4202 return (true); 4203 } 4204 if (obj->versyms == NULL) { 4205 if (object_match_name(obj, req->ventry->name)) { 4206 _rtld_error("%s: object %s should provide version %s " 4207 "for symbol %s", obj_rtld.path, obj->path, 4208 req->ventry->name, obj->strtab + symnum); 4209 return (false); 4210 } 4211 } else { 4212 verndx = VER_NDX(obj->versyms[symnum]); 4213 if (verndx > obj->vernum) { 4214 _rtld_error("%s: symbol %s references wrong version %d", 4215 obj->path, obj->strtab + symnum, verndx); 4216 return (false); 4217 } 4218 if (obj->vertab[verndx].hash != req->ventry->hash || 4219 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4220 /* 4221 * Version does not match. Look if this is a 4222 * global symbol and if it is not hidden. If 4223 * global symbol (verndx < 2) is available, 4224 * use it. Do not return symbol if we are 4225 * called by dlvsym, because dlvsym looks for 4226 * a specific version and default one is not 4227 * what dlvsym wants. 4228 */ 4229 if ((req->flags & SYMLOOK_DLSYM) || 4230 (verndx >= VER_NDX_GIVEN) || 4231 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4232 return (false); 4233 } 4234 } 4235 result->sym_out = symp; 4236 return (true); 4237 } 4238 4239 /* 4240 * Search for symbol using SysV hash function. 4241 * obj->buckets is known not to be NULL at this point; the test for this was 4242 * performed with the obj->valid_hash_sysv assignment. 4243 */ 4244 static int 4245 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4246 { 4247 unsigned long symnum; 4248 Sym_Match_Result matchres; 4249 4250 matchres.sym_out = NULL; 4251 matchres.vsymp = NULL; 4252 matchres.vcount = 0; 4253 4254 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4255 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4256 if (symnum >= obj->nchains) 4257 return (ESRCH); /* Bad object */ 4258 4259 if (matched_symbol(req, obj, &matchres, symnum)) { 4260 req->sym_out = matchres.sym_out; 4261 req->defobj_out = obj; 4262 return (0); 4263 } 4264 } 4265 if (matchres.vcount == 1) { 4266 req->sym_out = matchres.vsymp; 4267 req->defobj_out = obj; 4268 return (0); 4269 } 4270 return (ESRCH); 4271 } 4272 4273 /* Search for symbol using GNU hash function */ 4274 static int 4275 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4276 { 4277 Elf_Addr bloom_word; 4278 const Elf32_Word *hashval; 4279 Elf32_Word bucket; 4280 Sym_Match_Result matchres; 4281 unsigned int h1, h2; 4282 unsigned long symnum; 4283 4284 matchres.sym_out = NULL; 4285 matchres.vsymp = NULL; 4286 matchres.vcount = 0; 4287 4288 /* Pick right bitmask word from Bloom filter array */ 4289 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4290 obj->maskwords_bm_gnu]; 4291 4292 /* Calculate modulus word size of gnu hash and its derivative */ 4293 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4294 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4295 4296 /* Filter out the "definitely not in set" queries */ 4297 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4298 return (ESRCH); 4299 4300 /* Locate hash chain and corresponding value element*/ 4301 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4302 if (bucket == 0) 4303 return (ESRCH); 4304 hashval = &obj->chain_zero_gnu[bucket]; 4305 do { 4306 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4307 symnum = hashval - obj->chain_zero_gnu; 4308 if (matched_symbol(req, obj, &matchres, symnum)) { 4309 req->sym_out = matchres.sym_out; 4310 req->defobj_out = obj; 4311 return (0); 4312 } 4313 } 4314 } while ((*hashval++ & 1) == 0); 4315 if (matchres.vcount == 1) { 4316 req->sym_out = matchres.vsymp; 4317 req->defobj_out = obj; 4318 return (0); 4319 } 4320 return (ESRCH); 4321 } 4322 4323 static void 4324 trace_loaded_objects(Obj_Entry *obj) 4325 { 4326 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4327 int c; 4328 4329 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4330 main_local = ""; 4331 4332 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4333 fmt1 = "\t%o => %p (%x)\n"; 4334 4335 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4336 fmt2 = "\t%o (%x)\n"; 4337 4338 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4339 4340 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4341 Needed_Entry *needed; 4342 char *name, *path; 4343 bool is_lib; 4344 4345 if (obj->marker) 4346 continue; 4347 if (list_containers && obj->needed != NULL) 4348 rtld_printf("%s:\n", obj->path); 4349 for (needed = obj->needed; needed; needed = needed->next) { 4350 if (needed->obj != NULL) { 4351 if (needed->obj->traced && !list_containers) 4352 continue; 4353 needed->obj->traced = true; 4354 path = needed->obj->path; 4355 } else 4356 path = "not found"; 4357 4358 name = (char *)obj->strtab + needed->name; 4359 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4360 4361 fmt = is_lib ? fmt1 : fmt2; 4362 while ((c = *fmt++) != '\0') { 4363 switch (c) { 4364 default: 4365 rtld_putchar(c); 4366 continue; 4367 case '\\': 4368 switch (c = *fmt) { 4369 case '\0': 4370 continue; 4371 case 'n': 4372 rtld_putchar('\n'); 4373 break; 4374 case 't': 4375 rtld_putchar('\t'); 4376 break; 4377 } 4378 break; 4379 case '%': 4380 switch (c = *fmt) { 4381 case '\0': 4382 continue; 4383 case '%': 4384 default: 4385 rtld_putchar(c); 4386 break; 4387 case 'A': 4388 rtld_putstr(main_local); 4389 break; 4390 case 'a': 4391 rtld_putstr(obj_main->path); 4392 break; 4393 case 'o': 4394 rtld_putstr(name); 4395 break; 4396 #if 0 4397 case 'm': 4398 rtld_printf("%d", sodp->sod_major); 4399 break; 4400 case 'n': 4401 rtld_printf("%d", sodp->sod_minor); 4402 break; 4403 #endif 4404 case 'p': 4405 rtld_putstr(path); 4406 break; 4407 case 'x': 4408 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4409 0); 4410 break; 4411 } 4412 break; 4413 } 4414 ++fmt; 4415 } 4416 } 4417 } 4418 } 4419 4420 /* 4421 * Unload a dlopened object and its dependencies from memory and from 4422 * our data structures. It is assumed that the DAG rooted in the 4423 * object has already been unreferenced, and that the object has a 4424 * reference count of 0. 4425 */ 4426 static void 4427 unload_object(Obj_Entry *root) 4428 { 4429 Obj_Entry marker, *obj, *next; 4430 4431 assert(root->refcount == 0); 4432 4433 /* 4434 * Pass over the DAG removing unreferenced objects from 4435 * appropriate lists. 4436 */ 4437 unlink_object(root); 4438 4439 /* Unmap all objects that are no longer referenced. */ 4440 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4441 next = TAILQ_NEXT(obj, next); 4442 if (obj->marker || obj->refcount != 0) 4443 continue; 4444 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4445 obj->mapsize, 0, obj->path); 4446 dbg("unloading \"%s\"", obj->path); 4447 /* 4448 * Unlink the object now to prevent new references from 4449 * being acquired while the bind lock is dropped in 4450 * recursive dlclose() invocations. 4451 */ 4452 TAILQ_REMOVE(&obj_list, obj, next); 4453 obj_count--; 4454 4455 if (obj->filtees_loaded) { 4456 if (next != NULL) { 4457 init_marker(&marker); 4458 TAILQ_INSERT_BEFORE(next, &marker, next); 4459 unload_filtees(obj); 4460 next = TAILQ_NEXT(&marker, next); 4461 TAILQ_REMOVE(&obj_list, &marker, next); 4462 } else 4463 unload_filtees(obj); 4464 } 4465 release_object(obj); 4466 } 4467 } 4468 4469 static void 4470 unlink_object(Obj_Entry *root) 4471 { 4472 Objlist_Entry *elm; 4473 4474 if (root->refcount == 0) { 4475 /* Remove the object from the RTLD_GLOBAL list. */ 4476 objlist_remove(&list_global, root); 4477 4478 /* Remove the object from all objects' DAG lists. */ 4479 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4480 objlist_remove(&elm->obj->dldags, root); 4481 if (elm->obj != root) 4482 unlink_object(elm->obj); 4483 } 4484 } 4485 } 4486 4487 static void 4488 ref_dag(Obj_Entry *root) 4489 { 4490 Objlist_Entry *elm; 4491 4492 assert(root->dag_inited); 4493 STAILQ_FOREACH(elm, &root->dagmembers, link) 4494 elm->obj->refcount++; 4495 } 4496 4497 static void 4498 unref_dag(Obj_Entry *root) 4499 { 4500 Objlist_Entry *elm; 4501 4502 assert(root->dag_inited); 4503 STAILQ_FOREACH(elm, &root->dagmembers, link) 4504 elm->obj->refcount--; 4505 } 4506 4507 /* 4508 * Common code for MD __tls_get_addr(). 4509 */ 4510 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4511 static void * 4512 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4513 { 4514 Elf_Addr *newdtv, *dtv; 4515 RtldLockState lockstate; 4516 int to_copy; 4517 4518 dtv = *dtvp; 4519 /* Check dtv generation in case new modules have arrived */ 4520 if (dtv[0] != tls_dtv_generation) { 4521 wlock_acquire(rtld_bind_lock, &lockstate); 4522 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4523 to_copy = dtv[1]; 4524 if (to_copy > tls_max_index) 4525 to_copy = tls_max_index; 4526 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4527 newdtv[0] = tls_dtv_generation; 4528 newdtv[1] = tls_max_index; 4529 free(dtv); 4530 lock_release(rtld_bind_lock, &lockstate); 4531 dtv = *dtvp = newdtv; 4532 } 4533 4534 /* Dynamically allocate module TLS if necessary */ 4535 if (dtv[index + 1] == 0) { 4536 /* Signal safe, wlock will block out signals. */ 4537 wlock_acquire(rtld_bind_lock, &lockstate); 4538 if (!dtv[index + 1]) 4539 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4540 lock_release(rtld_bind_lock, &lockstate); 4541 } 4542 return ((void *)(dtv[index + 1] + offset)); 4543 } 4544 4545 void * 4546 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4547 { 4548 Elf_Addr *dtv; 4549 4550 dtv = *dtvp; 4551 /* Check dtv generation in case new modules have arrived */ 4552 if (__predict_true(dtv[0] == tls_dtv_generation && 4553 dtv[index + 1] != 0)) 4554 return ((void *)(dtv[index + 1] + offset)); 4555 return (tls_get_addr_slow(dtvp, index, offset)); 4556 } 4557 4558 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4559 defined(__powerpc__) || defined(__riscv__) 4560 4561 /* 4562 * Allocate Static TLS using the Variant I method. 4563 */ 4564 void * 4565 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4566 { 4567 Obj_Entry *obj; 4568 char *tcb; 4569 Elf_Addr **tls; 4570 Elf_Addr *dtv; 4571 Elf_Addr addr; 4572 int i; 4573 4574 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4575 return (oldtcb); 4576 4577 assert(tcbsize >= TLS_TCB_SIZE); 4578 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4579 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4580 4581 if (oldtcb != NULL) { 4582 memcpy(tls, oldtcb, tls_static_space); 4583 free(oldtcb); 4584 4585 /* Adjust the DTV. */ 4586 dtv = tls[0]; 4587 for (i = 0; i < dtv[1]; i++) { 4588 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4589 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4590 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4591 } 4592 } 4593 } else { 4594 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4595 tls[0] = dtv; 4596 dtv[0] = tls_dtv_generation; 4597 dtv[1] = tls_max_index; 4598 4599 for (obj = globallist_curr(objs); obj != NULL; 4600 obj = globallist_next(obj)) { 4601 if (obj->tlsoffset > 0) { 4602 addr = (Elf_Addr)tls + obj->tlsoffset; 4603 if (obj->tlsinitsize > 0) 4604 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4605 if (obj->tlssize > obj->tlsinitsize) 4606 memset((void*) (addr + obj->tlsinitsize), 0, 4607 obj->tlssize - obj->tlsinitsize); 4608 dtv[obj->tlsindex + 1] = addr; 4609 } 4610 } 4611 } 4612 4613 return (tcb); 4614 } 4615 4616 void 4617 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4618 { 4619 Elf_Addr *dtv; 4620 Elf_Addr tlsstart, tlsend; 4621 int dtvsize, i; 4622 4623 assert(tcbsize >= TLS_TCB_SIZE); 4624 4625 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4626 tlsend = tlsstart + tls_static_space; 4627 4628 dtv = *(Elf_Addr **)tlsstart; 4629 dtvsize = dtv[1]; 4630 for (i = 0; i < dtvsize; i++) { 4631 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4632 free((void*)dtv[i+2]); 4633 } 4634 } 4635 free(dtv); 4636 free(tcb); 4637 } 4638 4639 #endif 4640 4641 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4642 4643 /* 4644 * Allocate Static TLS using the Variant II method. 4645 */ 4646 void * 4647 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4648 { 4649 Obj_Entry *obj; 4650 size_t size, ralign; 4651 char *tls; 4652 Elf_Addr *dtv, *olddtv; 4653 Elf_Addr segbase, oldsegbase, addr; 4654 int i; 4655 4656 ralign = tcbalign; 4657 if (tls_static_max_align > ralign) 4658 ralign = tls_static_max_align; 4659 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4660 4661 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4662 tls = malloc_aligned(size, ralign); 4663 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4664 4665 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4666 ((Elf_Addr*)segbase)[0] = segbase; 4667 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4668 4669 dtv[0] = tls_dtv_generation; 4670 dtv[1] = tls_max_index; 4671 4672 if (oldtls) { 4673 /* 4674 * Copy the static TLS block over whole. 4675 */ 4676 oldsegbase = (Elf_Addr) oldtls; 4677 memcpy((void *)(segbase - tls_static_space), 4678 (const void *)(oldsegbase - tls_static_space), 4679 tls_static_space); 4680 4681 /* 4682 * If any dynamic TLS blocks have been created tls_get_addr(), 4683 * move them over. 4684 */ 4685 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4686 for (i = 0; i < olddtv[1]; i++) { 4687 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4688 dtv[i+2] = olddtv[i+2]; 4689 olddtv[i+2] = 0; 4690 } 4691 } 4692 4693 /* 4694 * We assume that this block was the one we created with 4695 * allocate_initial_tls(). 4696 */ 4697 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4698 } else { 4699 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4700 if (obj->marker || obj->tlsoffset == 0) 4701 continue; 4702 addr = segbase - obj->tlsoffset; 4703 memset((void*) (addr + obj->tlsinitsize), 4704 0, obj->tlssize - obj->tlsinitsize); 4705 if (obj->tlsinit) 4706 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4707 dtv[obj->tlsindex + 1] = addr; 4708 } 4709 } 4710 4711 return (void*) segbase; 4712 } 4713 4714 void 4715 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4716 { 4717 Elf_Addr* dtv; 4718 size_t size, ralign; 4719 int dtvsize, i; 4720 Elf_Addr tlsstart, tlsend; 4721 4722 /* 4723 * Figure out the size of the initial TLS block so that we can 4724 * find stuff which ___tls_get_addr() allocated dynamically. 4725 */ 4726 ralign = tcbalign; 4727 if (tls_static_max_align > ralign) 4728 ralign = tls_static_max_align; 4729 size = round(tls_static_space, ralign); 4730 4731 dtv = ((Elf_Addr**)tls)[1]; 4732 dtvsize = dtv[1]; 4733 tlsend = (Elf_Addr) tls; 4734 tlsstart = tlsend - size; 4735 for (i = 0; i < dtvsize; i++) { 4736 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4737 free_aligned((void *)dtv[i + 2]); 4738 } 4739 } 4740 4741 free_aligned((void *)tlsstart); 4742 free((void*) dtv); 4743 } 4744 4745 #endif 4746 4747 /* 4748 * Allocate TLS block for module with given index. 4749 */ 4750 void * 4751 allocate_module_tls(int index) 4752 { 4753 Obj_Entry* obj; 4754 char* p; 4755 4756 TAILQ_FOREACH(obj, &obj_list, next) { 4757 if (obj->marker) 4758 continue; 4759 if (obj->tlsindex == index) 4760 break; 4761 } 4762 if (!obj) { 4763 _rtld_error("Can't find module with TLS index %d", index); 4764 rtld_die(); 4765 } 4766 4767 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4768 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4769 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4770 4771 return p; 4772 } 4773 4774 bool 4775 allocate_tls_offset(Obj_Entry *obj) 4776 { 4777 size_t off; 4778 4779 if (obj->tls_done) 4780 return true; 4781 4782 if (obj->tlssize == 0) { 4783 obj->tls_done = true; 4784 return true; 4785 } 4786 4787 if (tls_last_offset == 0) 4788 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4789 else 4790 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4791 obj->tlssize, obj->tlsalign); 4792 4793 /* 4794 * If we have already fixed the size of the static TLS block, we 4795 * must stay within that size. When allocating the static TLS, we 4796 * leave a small amount of space spare to be used for dynamically 4797 * loading modules which use static TLS. 4798 */ 4799 if (tls_static_space != 0) { 4800 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4801 return false; 4802 } else if (obj->tlsalign > tls_static_max_align) { 4803 tls_static_max_align = obj->tlsalign; 4804 } 4805 4806 tls_last_offset = obj->tlsoffset = off; 4807 tls_last_size = obj->tlssize; 4808 obj->tls_done = true; 4809 4810 return true; 4811 } 4812 4813 void 4814 free_tls_offset(Obj_Entry *obj) 4815 { 4816 4817 /* 4818 * If we were the last thing to allocate out of the static TLS 4819 * block, we give our space back to the 'allocator'. This is a 4820 * simplistic workaround to allow libGL.so.1 to be loaded and 4821 * unloaded multiple times. 4822 */ 4823 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4824 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4825 tls_last_offset -= obj->tlssize; 4826 tls_last_size = 0; 4827 } 4828 } 4829 4830 void * 4831 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4832 { 4833 void *ret; 4834 RtldLockState lockstate; 4835 4836 wlock_acquire(rtld_bind_lock, &lockstate); 4837 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4838 tcbsize, tcbalign); 4839 lock_release(rtld_bind_lock, &lockstate); 4840 return (ret); 4841 } 4842 4843 void 4844 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4845 { 4846 RtldLockState lockstate; 4847 4848 wlock_acquire(rtld_bind_lock, &lockstate); 4849 free_tls(tcb, tcbsize, tcbalign); 4850 lock_release(rtld_bind_lock, &lockstate); 4851 } 4852 4853 static void 4854 object_add_name(Obj_Entry *obj, const char *name) 4855 { 4856 Name_Entry *entry; 4857 size_t len; 4858 4859 len = strlen(name); 4860 entry = malloc(sizeof(Name_Entry) + len); 4861 4862 if (entry != NULL) { 4863 strcpy(entry->name, name); 4864 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4865 } 4866 } 4867 4868 static int 4869 object_match_name(const Obj_Entry *obj, const char *name) 4870 { 4871 Name_Entry *entry; 4872 4873 STAILQ_FOREACH(entry, &obj->names, link) { 4874 if (strcmp(name, entry->name) == 0) 4875 return (1); 4876 } 4877 return (0); 4878 } 4879 4880 static Obj_Entry * 4881 locate_dependency(const Obj_Entry *obj, const char *name) 4882 { 4883 const Objlist_Entry *entry; 4884 const Needed_Entry *needed; 4885 4886 STAILQ_FOREACH(entry, &list_main, link) { 4887 if (object_match_name(entry->obj, name)) 4888 return entry->obj; 4889 } 4890 4891 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4892 if (strcmp(obj->strtab + needed->name, name) == 0 || 4893 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4894 /* 4895 * If there is DT_NEEDED for the name we are looking for, 4896 * we are all set. Note that object might not be found if 4897 * dependency was not loaded yet, so the function can 4898 * return NULL here. This is expected and handled 4899 * properly by the caller. 4900 */ 4901 return (needed->obj); 4902 } 4903 } 4904 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4905 obj->path, name); 4906 rtld_die(); 4907 } 4908 4909 static int 4910 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4911 const Elf_Vernaux *vna) 4912 { 4913 const Elf_Verdef *vd; 4914 const char *vername; 4915 4916 vername = refobj->strtab + vna->vna_name; 4917 vd = depobj->verdef; 4918 if (vd == NULL) { 4919 _rtld_error("%s: version %s required by %s not defined", 4920 depobj->path, vername, refobj->path); 4921 return (-1); 4922 } 4923 for (;;) { 4924 if (vd->vd_version != VER_DEF_CURRENT) { 4925 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4926 depobj->path, vd->vd_version); 4927 return (-1); 4928 } 4929 if (vna->vna_hash == vd->vd_hash) { 4930 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4931 ((char *)vd + vd->vd_aux); 4932 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4933 return (0); 4934 } 4935 if (vd->vd_next == 0) 4936 break; 4937 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4938 } 4939 if (vna->vna_flags & VER_FLG_WEAK) 4940 return (0); 4941 _rtld_error("%s: version %s required by %s not found", 4942 depobj->path, vername, refobj->path); 4943 return (-1); 4944 } 4945 4946 static int 4947 rtld_verify_object_versions(Obj_Entry *obj) 4948 { 4949 const Elf_Verneed *vn; 4950 const Elf_Verdef *vd; 4951 const Elf_Verdaux *vda; 4952 const Elf_Vernaux *vna; 4953 const Obj_Entry *depobj; 4954 int maxvernum, vernum; 4955 4956 if (obj->ver_checked) 4957 return (0); 4958 obj->ver_checked = true; 4959 4960 maxvernum = 0; 4961 /* 4962 * Walk over defined and required version records and figure out 4963 * max index used by any of them. Do very basic sanity checking 4964 * while there. 4965 */ 4966 vn = obj->verneed; 4967 while (vn != NULL) { 4968 if (vn->vn_version != VER_NEED_CURRENT) { 4969 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4970 obj->path, vn->vn_version); 4971 return (-1); 4972 } 4973 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4974 for (;;) { 4975 vernum = VER_NEED_IDX(vna->vna_other); 4976 if (vernum > maxvernum) 4977 maxvernum = vernum; 4978 if (vna->vna_next == 0) 4979 break; 4980 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4981 } 4982 if (vn->vn_next == 0) 4983 break; 4984 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4985 } 4986 4987 vd = obj->verdef; 4988 while (vd != NULL) { 4989 if (vd->vd_version != VER_DEF_CURRENT) { 4990 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4991 obj->path, vd->vd_version); 4992 return (-1); 4993 } 4994 vernum = VER_DEF_IDX(vd->vd_ndx); 4995 if (vernum > maxvernum) 4996 maxvernum = vernum; 4997 if (vd->vd_next == 0) 4998 break; 4999 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5000 } 5001 5002 if (maxvernum == 0) 5003 return (0); 5004 5005 /* 5006 * Store version information in array indexable by version index. 5007 * Verify that object version requirements are satisfied along the 5008 * way. 5009 */ 5010 obj->vernum = maxvernum + 1; 5011 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5012 5013 vd = obj->verdef; 5014 while (vd != NULL) { 5015 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5016 vernum = VER_DEF_IDX(vd->vd_ndx); 5017 assert(vernum <= maxvernum); 5018 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5019 obj->vertab[vernum].hash = vd->vd_hash; 5020 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5021 obj->vertab[vernum].file = NULL; 5022 obj->vertab[vernum].flags = 0; 5023 } 5024 if (vd->vd_next == 0) 5025 break; 5026 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5027 } 5028 5029 vn = obj->verneed; 5030 while (vn != NULL) { 5031 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5032 if (depobj == NULL) 5033 return (-1); 5034 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5035 for (;;) { 5036 if (check_object_provided_version(obj, depobj, vna)) 5037 return (-1); 5038 vernum = VER_NEED_IDX(vna->vna_other); 5039 assert(vernum <= maxvernum); 5040 obj->vertab[vernum].hash = vna->vna_hash; 5041 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5042 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5043 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5044 VER_INFO_HIDDEN : 0; 5045 if (vna->vna_next == 0) 5046 break; 5047 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5048 } 5049 if (vn->vn_next == 0) 5050 break; 5051 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5052 } 5053 return 0; 5054 } 5055 5056 static int 5057 rtld_verify_versions(const Objlist *objlist) 5058 { 5059 Objlist_Entry *entry; 5060 int rc; 5061 5062 rc = 0; 5063 STAILQ_FOREACH(entry, objlist, link) { 5064 /* 5065 * Skip dummy objects or objects that have their version requirements 5066 * already checked. 5067 */ 5068 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5069 continue; 5070 if (rtld_verify_object_versions(entry->obj) == -1) { 5071 rc = -1; 5072 if (ld_tracing == NULL) 5073 break; 5074 } 5075 } 5076 if (rc == 0 || ld_tracing != NULL) 5077 rc = rtld_verify_object_versions(&obj_rtld); 5078 return rc; 5079 } 5080 5081 const Ver_Entry * 5082 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5083 { 5084 Elf_Versym vernum; 5085 5086 if (obj->vertab) { 5087 vernum = VER_NDX(obj->versyms[symnum]); 5088 if (vernum >= obj->vernum) { 5089 _rtld_error("%s: symbol %s has wrong verneed value %d", 5090 obj->path, obj->strtab + symnum, vernum); 5091 } else if (obj->vertab[vernum].hash != 0) { 5092 return &obj->vertab[vernum]; 5093 } 5094 } 5095 return NULL; 5096 } 5097 5098 int 5099 _rtld_get_stack_prot(void) 5100 { 5101 5102 return (stack_prot); 5103 } 5104 5105 int 5106 _rtld_is_dlopened(void *arg) 5107 { 5108 Obj_Entry *obj; 5109 RtldLockState lockstate; 5110 int res; 5111 5112 rlock_acquire(rtld_bind_lock, &lockstate); 5113 obj = dlcheck(arg); 5114 if (obj == NULL) 5115 obj = obj_from_addr(arg); 5116 if (obj == NULL) { 5117 _rtld_error("No shared object contains address"); 5118 lock_release(rtld_bind_lock, &lockstate); 5119 return (-1); 5120 } 5121 res = obj->dlopened ? 1 : 0; 5122 lock_release(rtld_bind_lock, &lockstate); 5123 return (res); 5124 } 5125 5126 int 5127 obj_enforce_relro(Obj_Entry *obj) 5128 { 5129 5130 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5131 PROT_READ) == -1) { 5132 _rtld_error("%s: Cannot enforce relro protection: %s", 5133 obj->path, rtld_strerror(errno)); 5134 return (-1); 5135 } 5136 return (0); 5137 } 5138 5139 static void 5140 map_stacks_exec(RtldLockState *lockstate) 5141 { 5142 void (*thr_map_stacks_exec)(void); 5143 5144 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5145 return; 5146 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5147 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5148 if (thr_map_stacks_exec != NULL) { 5149 stack_prot |= PROT_EXEC; 5150 thr_map_stacks_exec(); 5151 } 5152 } 5153 5154 void 5155 symlook_init(SymLook *dst, const char *name) 5156 { 5157 5158 bzero(dst, sizeof(*dst)); 5159 dst->name = name; 5160 dst->hash = elf_hash(name); 5161 dst->hash_gnu = gnu_hash(name); 5162 } 5163 5164 static void 5165 symlook_init_from_req(SymLook *dst, const SymLook *src) 5166 { 5167 5168 dst->name = src->name; 5169 dst->hash = src->hash; 5170 dst->hash_gnu = src->hash_gnu; 5171 dst->ventry = src->ventry; 5172 dst->flags = src->flags; 5173 dst->defobj_out = NULL; 5174 dst->sym_out = NULL; 5175 dst->lockstate = src->lockstate; 5176 } 5177 5178 5179 /* 5180 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5181 */ 5182 static int 5183 parse_libdir(const char *str) 5184 { 5185 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5186 const char *orig; 5187 int fd; 5188 char c; 5189 5190 orig = str; 5191 fd = 0; 5192 for (c = *str; c != '\0'; c = *++str) { 5193 if (c < '0' || c > '9') 5194 return (-1); 5195 5196 fd *= RADIX; 5197 fd += c - '0'; 5198 } 5199 5200 /* Make sure we actually parsed something. */ 5201 if (str == orig) { 5202 _rtld_error("failed to parse directory FD from '%s'", str); 5203 return (-1); 5204 } 5205 return (fd); 5206 } 5207 5208 /* 5209 * Overrides for libc_pic-provided functions. 5210 */ 5211 5212 int 5213 __getosreldate(void) 5214 { 5215 size_t len; 5216 int oid[2]; 5217 int error, osrel; 5218 5219 if (osreldate != 0) 5220 return (osreldate); 5221 5222 oid[0] = CTL_KERN; 5223 oid[1] = KERN_OSRELDATE; 5224 osrel = 0; 5225 len = sizeof(osrel); 5226 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5227 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5228 osreldate = osrel; 5229 return (osreldate); 5230 } 5231 5232 void 5233 exit(int status) 5234 { 5235 5236 _exit(status); 5237 } 5238 5239 void (*__cleanup)(void); 5240 int __isthreaded = 0; 5241 int _thread_autoinit_dummy_decl = 1; 5242 5243 /* 5244 * No unresolved symbols for rtld. 5245 */ 5246 void 5247 __pthread_cxa_finalize(struct dl_phdr_info *a) 5248 { 5249 } 5250 5251 void 5252 __stack_chk_fail(void) 5253 { 5254 5255 _rtld_error("stack overflow detected; terminated"); 5256 rtld_die(); 5257 } 5258 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5259 5260 void 5261 __chk_fail(void) 5262 { 5263 5264 _rtld_error("buffer overflow detected; terminated"); 5265 rtld_die(); 5266 } 5267 5268 const char * 5269 rtld_strerror(int errnum) 5270 { 5271 5272 if (errnum < 0 || errnum >= sys_nerr) 5273 return ("Unknown error"); 5274 return (sys_errlist[errnum]); 5275 } 5276