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 int dlclose_locked(void *, RtldLockState *); 81 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 82 int lo_flags, int mode, RtldLockState *lockstate); 83 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 84 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 85 static bool donelist_check(DoneList *, const Obj_Entry *); 86 static void errmsg_restore(char *); 87 static char *errmsg_save(void); 88 static void *fill_search_info(const char *, size_t, void *); 89 static char *find_library(const char *, const Obj_Entry *, int *); 90 static const char *gethints(bool); 91 static void hold_object(Obj_Entry *); 92 static void unhold_object(Obj_Entry *); 93 static void init_dag(Obj_Entry *); 94 static void init_marker(Obj_Entry *); 95 static void init_pagesizes(Elf_Auxinfo **aux_info); 96 static void init_rtld(caddr_t, Elf_Auxinfo **); 97 static void initlist_add_neededs(Needed_Entry *, Objlist *); 98 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 99 static void linkmap_add(Obj_Entry *); 100 static void linkmap_delete(Obj_Entry *); 101 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 102 static void unload_filtees(Obj_Entry *, RtldLockState *); 103 static int load_needed_objects(Obj_Entry *, int); 104 static int load_preload_objects(void); 105 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 106 static void map_stacks_exec(RtldLockState *); 107 static int obj_enforce_relro(Obj_Entry *); 108 static Obj_Entry *obj_from_addr(const void *); 109 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 110 static void objlist_call_init(Objlist *, RtldLockState *); 111 static void objlist_clear(Objlist *); 112 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 113 static void objlist_init(Objlist *); 114 static void objlist_push_head(Objlist *, Obj_Entry *); 115 static void objlist_push_tail(Objlist *, Obj_Entry *); 116 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 117 static void objlist_remove(Objlist *, Obj_Entry *); 118 static int parse_libdir(const char *); 119 static void *path_enumerate(const char *, path_enum_proc, void *); 120 static void release_object(Obj_Entry *); 121 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 122 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 123 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 124 int flags, RtldLockState *lockstate); 125 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 126 RtldLockState *); 127 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 128 int flags, RtldLockState *lockstate); 129 static int rtld_dirname(const char *, char *); 130 static int rtld_dirname_abs(const char *, char *); 131 static void *rtld_dlopen(const char *name, int fd, int mode); 132 static void rtld_exit(void); 133 static char *search_library_path(const char *, const char *); 134 static char *search_library_pathfds(const char *, const char *, int *); 135 static const void **get_program_var_addr(const char *, RtldLockState *); 136 static void set_program_var(const char *, const void *); 137 static int symlook_default(SymLook *, const Obj_Entry *refobj); 138 static int symlook_global(SymLook *, DoneList *); 139 static void symlook_init_from_req(SymLook *, const SymLook *); 140 static int symlook_list(SymLook *, const Objlist *, DoneList *); 141 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 142 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 143 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 144 static void trace_loaded_objects(Obj_Entry *); 145 static void unlink_object(Obj_Entry *); 146 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 147 static void unref_dag(Obj_Entry *); 148 static void ref_dag(Obj_Entry *); 149 static char *origin_subst_one(Obj_Entry *, char *, const char *, 150 const char *, bool); 151 static char *origin_subst(Obj_Entry *, char *); 152 static bool obj_resolve_origin(Obj_Entry *obj); 153 static void preinit_main(void); 154 static int rtld_verify_versions(const Objlist *); 155 static int rtld_verify_object_versions(Obj_Entry *); 156 static void object_add_name(Obj_Entry *, const char *); 157 static int object_match_name(const Obj_Entry *, const char *); 158 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 159 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 160 struct dl_phdr_info *phdr_info); 161 static uint32_t gnu_hash(const char *); 162 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 163 const unsigned long); 164 165 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 166 void _r_debug_postinit(struct link_map *) __noinline __exported; 167 168 int __sys_openat(int, const char *, int, ...); 169 170 /* 171 * Data declarations. 172 */ 173 static char *error_message; /* Message for dlerror(), or NULL */ 174 struct r_debug r_debug __exported; /* for GDB; */ 175 static bool libmap_disable; /* Disable libmap */ 176 static bool ld_loadfltr; /* Immediate filters processing */ 177 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 178 static bool trust; /* False for setuid and setgid programs */ 179 static bool dangerous_ld_env; /* True if environment variables have been 180 used to affect the libraries loaded */ 181 static char *ld_bind_now; /* Environment variable for immediate binding */ 182 static char *ld_debug; /* Environment variable for debugging */ 183 static char *ld_library_path; /* Environment variable for search path */ 184 static char *ld_library_dirs; /* Environment variable for library descriptors */ 185 static char *ld_preload; /* Environment variable for libraries to 186 load first */ 187 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 188 static char *ld_tracing; /* Called from ldd to print libs */ 189 static char *ld_utrace; /* Use utrace() to log events. */ 190 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 191 static Obj_Entry *obj_main; /* The main program shared object */ 192 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 193 static unsigned int obj_count; /* Number of objects in obj_list */ 194 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 195 196 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 197 STAILQ_HEAD_INITIALIZER(list_global); 198 static Objlist list_main = /* Objects loaded at program startup */ 199 STAILQ_HEAD_INITIALIZER(list_main); 200 static Objlist list_fini = /* Objects needing fini() calls */ 201 STAILQ_HEAD_INITIALIZER(list_fini); 202 203 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 204 205 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 206 207 extern Elf_Dyn _DYNAMIC; 208 #pragma weak _DYNAMIC 209 210 int dlclose(void *) __exported; 211 char *dlerror(void) __exported; 212 void *dlopen(const char *, int) __exported; 213 void *fdlopen(int, int) __exported; 214 void *dlsym(void *, const char *) __exported; 215 dlfunc_t dlfunc(void *, const char *) __exported; 216 void *dlvsym(void *, const char *, const char *) __exported; 217 int dladdr(const void *, Dl_info *) __exported; 218 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 219 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 220 int dlinfo(void *, int , void *) __exported; 221 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 222 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 223 int _rtld_get_stack_prot(void) __exported; 224 int _rtld_is_dlopened(void *) __exported; 225 void _rtld_error(const char *, ...) __exported; 226 227 int npagesizes, osreldate; 228 size_t *pagesizes; 229 230 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 231 232 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 233 static int max_stack_flags; 234 235 /* 236 * Global declarations normally provided by crt1. The dynamic linker is 237 * not built with crt1, so we have to provide them ourselves. 238 */ 239 char *__progname; 240 char **environ; 241 242 /* 243 * Used to pass argc, argv to init functions. 244 */ 245 int main_argc; 246 char **main_argv; 247 248 /* 249 * Globals to control TLS allocation. 250 */ 251 size_t tls_last_offset; /* Static TLS offset of last module */ 252 size_t tls_last_size; /* Static TLS size of last module */ 253 size_t tls_static_space; /* Static TLS space allocated */ 254 size_t tls_static_max_align; 255 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 256 int tls_max_index = 1; /* Largest module index allocated */ 257 258 bool ld_library_path_rpath = false; 259 260 /* 261 * Globals for path names, and such 262 */ 263 char *ld_elf_hints_default = _PATH_ELF_HINTS; 264 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 265 char *ld_path_rtld = _PATH_RTLD; 266 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 267 char *ld_env_prefix = LD_; 268 269 /* 270 * Fill in a DoneList with an allocation large enough to hold all of 271 * the currently-loaded objects. Keep this as a macro since it calls 272 * alloca and we want that to occur within the scope of the caller. 273 */ 274 #define donelist_init(dlp) \ 275 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 276 assert((dlp)->objs != NULL), \ 277 (dlp)->num_alloc = obj_count, \ 278 (dlp)->num_used = 0) 279 280 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 281 if (ld_utrace != NULL) \ 282 ld_utrace_log(e, h, mb, ms, r, n); \ 283 } while (0) 284 285 static void 286 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 287 int refcnt, const char *name) 288 { 289 struct utrace_rtld ut; 290 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 291 292 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 293 ut.event = event; 294 ut.handle = handle; 295 ut.mapbase = mapbase; 296 ut.mapsize = mapsize; 297 ut.refcnt = refcnt; 298 bzero(ut.name, sizeof(ut.name)); 299 if (name) 300 strlcpy(ut.name, name, sizeof(ut.name)); 301 utrace(&ut, sizeof(ut)); 302 } 303 304 #ifdef RTLD_VARIANT_ENV_NAMES 305 /* 306 * construct the env variable based on the type of binary that's 307 * running. 308 */ 309 static inline const char * 310 _LD(const char *var) 311 { 312 static char buffer[128]; 313 314 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 315 strlcat(buffer, var, sizeof(buffer)); 316 return (buffer); 317 } 318 #else 319 #define _LD(x) LD_ x 320 #endif 321 322 /* 323 * Main entry point for dynamic linking. The first argument is the 324 * stack pointer. The stack is expected to be laid out as described 325 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 326 * Specifically, the stack pointer points to a word containing 327 * ARGC. Following that in the stack is a null-terminated sequence 328 * of pointers to argument strings. Then comes a null-terminated 329 * sequence of pointers to environment strings. Finally, there is a 330 * sequence of "auxiliary vector" entries. 331 * 332 * The second argument points to a place to store the dynamic linker's 333 * exit procedure pointer and the third to a place to store the main 334 * program's object. 335 * 336 * The return value is the main program's entry point. 337 */ 338 func_ptr_type 339 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 340 { 341 Elf_Auxinfo *aux_info[AT_COUNT]; 342 int i; 343 int argc; 344 char **argv; 345 char **env; 346 Elf_Auxinfo *aux; 347 Elf_Auxinfo *auxp; 348 const char *argv0; 349 Objlist_Entry *entry; 350 Obj_Entry *obj; 351 Obj_Entry *preload_tail; 352 Obj_Entry *last_interposer; 353 Objlist initlist; 354 RtldLockState lockstate; 355 char *library_path_rpath; 356 int mib[2]; 357 size_t len; 358 359 /* 360 * On entry, the dynamic linker itself has not been relocated yet. 361 * Be very careful not to reference any global data until after 362 * init_rtld has returned. It is OK to reference file-scope statics 363 * and string constants, and to call static and global functions. 364 */ 365 366 /* Find the auxiliary vector on the stack. */ 367 argc = *sp++; 368 argv = (char **) sp; 369 sp += argc + 1; /* Skip over arguments and NULL terminator */ 370 env = (char **) sp; 371 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 372 ; 373 aux = (Elf_Auxinfo *) sp; 374 375 /* Digest the auxiliary vector. */ 376 for (i = 0; i < AT_COUNT; i++) 377 aux_info[i] = NULL; 378 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 379 if (auxp->a_type < AT_COUNT) 380 aux_info[auxp->a_type] = auxp; 381 } 382 383 /* Initialize and relocate ourselves. */ 384 assert(aux_info[AT_BASE] != NULL); 385 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 386 387 __progname = obj_rtld.path; 388 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 389 environ = env; 390 main_argc = argc; 391 main_argv = argv; 392 393 if (aux_info[AT_CANARY] != NULL && 394 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 395 i = aux_info[AT_CANARYLEN]->a_un.a_val; 396 if (i > sizeof(__stack_chk_guard)) 397 i = sizeof(__stack_chk_guard); 398 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 399 } else { 400 mib[0] = CTL_KERN; 401 mib[1] = KERN_ARND; 402 403 len = sizeof(__stack_chk_guard); 404 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 405 len != sizeof(__stack_chk_guard)) { 406 /* If sysctl was unsuccessful, use the "terminator canary". */ 407 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 408 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 409 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 410 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 411 } 412 } 413 414 trust = !issetugid(); 415 416 md_abi_variant_hook(aux_info); 417 418 ld_bind_now = getenv(_LD("BIND_NOW")); 419 /* 420 * If the process is tainted, then we un-set the dangerous environment 421 * variables. The process will be marked as tainted until setuid(2) 422 * is called. If any child process calls setuid(2) we do not want any 423 * future processes to honor the potentially un-safe variables. 424 */ 425 if (!trust) { 426 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 427 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 428 unsetenv(_LD("LIBMAP_DISABLE")) || 429 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 430 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 431 _rtld_error("environment corrupt; aborting"); 432 rtld_die(); 433 } 434 } 435 ld_debug = getenv(_LD("DEBUG")); 436 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 437 libmap_override = getenv(_LD("LIBMAP")); 438 ld_library_path = getenv(_LD("LIBRARY_PATH")); 439 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 440 ld_preload = getenv(_LD("PRELOAD")); 441 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 442 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 443 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 444 if (library_path_rpath != NULL) { 445 if (library_path_rpath[0] == 'y' || 446 library_path_rpath[0] == 'Y' || 447 library_path_rpath[0] == '1') 448 ld_library_path_rpath = true; 449 else 450 ld_library_path_rpath = false; 451 } 452 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 453 (ld_library_path != NULL) || (ld_preload != NULL) || 454 (ld_elf_hints_path != NULL) || ld_loadfltr; 455 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 456 ld_utrace = getenv(_LD("UTRACE")); 457 458 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 459 ld_elf_hints_path = ld_elf_hints_default; 460 461 if (ld_debug != NULL && *ld_debug != '\0') 462 debug = 1; 463 dbg("%s is initialized, base address = %p", __progname, 464 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 465 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 466 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 467 468 dbg("initializing thread locks"); 469 lockdflt_init(); 470 471 /* 472 * Load the main program, or process its program header if it is 473 * already loaded. 474 */ 475 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 476 int fd = aux_info[AT_EXECFD]->a_un.a_val; 477 dbg("loading main program"); 478 obj_main = map_object(fd, argv0, NULL); 479 close(fd); 480 if (obj_main == NULL) 481 rtld_die(); 482 max_stack_flags = obj->stack_flags; 483 } else { /* Main program already loaded. */ 484 const Elf_Phdr *phdr; 485 int phnum; 486 caddr_t entry; 487 488 dbg("processing main program's program header"); 489 assert(aux_info[AT_PHDR] != NULL); 490 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 491 assert(aux_info[AT_PHNUM] != NULL); 492 phnum = aux_info[AT_PHNUM]->a_un.a_val; 493 assert(aux_info[AT_PHENT] != NULL); 494 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 495 assert(aux_info[AT_ENTRY] != NULL); 496 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 497 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 498 rtld_die(); 499 } 500 501 if (aux_info[AT_EXECPATH] != NULL) { 502 char *kexecpath; 503 char buf[MAXPATHLEN]; 504 505 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 506 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 507 if (kexecpath[0] == '/') 508 obj_main->path = kexecpath; 509 else if (getcwd(buf, sizeof(buf)) == NULL || 510 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 511 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 512 obj_main->path = xstrdup(argv0); 513 else 514 obj_main->path = xstrdup(buf); 515 } else { 516 dbg("No AT_EXECPATH"); 517 obj_main->path = xstrdup(argv0); 518 } 519 dbg("obj_main path %s", obj_main->path); 520 obj_main->mainprog = true; 521 522 if (aux_info[AT_STACKPROT] != NULL && 523 aux_info[AT_STACKPROT]->a_un.a_val != 0) 524 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 525 526 #ifndef COMPAT_32BIT 527 /* 528 * Get the actual dynamic linker pathname from the executable if 529 * possible. (It should always be possible.) That ensures that 530 * gdb will find the right dynamic linker even if a non-standard 531 * one is being used. 532 */ 533 if (obj_main->interp != NULL && 534 strcmp(obj_main->interp, obj_rtld.path) != 0) { 535 free(obj_rtld.path); 536 obj_rtld.path = xstrdup(obj_main->interp); 537 __progname = obj_rtld.path; 538 } 539 #endif 540 541 digest_dynamic(obj_main, 0); 542 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 543 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 544 obj_main->dynsymcount); 545 546 linkmap_add(obj_main); 547 linkmap_add(&obj_rtld); 548 549 /* Link the main program into the list of objects. */ 550 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 551 obj_count++; 552 obj_loads++; 553 554 /* Initialize a fake symbol for resolving undefined weak references. */ 555 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 556 sym_zero.st_shndx = SHN_UNDEF; 557 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 558 559 if (!libmap_disable) 560 libmap_disable = (bool)lm_init(libmap_override); 561 562 dbg("loading LD_PRELOAD libraries"); 563 if (load_preload_objects() == -1) 564 rtld_die(); 565 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 566 567 dbg("loading needed objects"); 568 if (load_needed_objects(obj_main, 0) == -1) 569 rtld_die(); 570 571 /* Make a list of all objects loaded at startup. */ 572 last_interposer = obj_main; 573 TAILQ_FOREACH(obj, &obj_list, next) { 574 if (obj->marker) 575 continue; 576 if (obj->z_interpose && obj != obj_main) { 577 objlist_put_after(&list_main, last_interposer, obj); 578 last_interposer = obj; 579 } else { 580 objlist_push_tail(&list_main, obj); 581 } 582 obj->refcount++; 583 } 584 585 dbg("checking for required versions"); 586 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 587 rtld_die(); 588 589 if (ld_tracing) { /* We're done */ 590 trace_loaded_objects(obj_main); 591 exit(0); 592 } 593 594 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 595 dump_relocations(obj_main); 596 exit (0); 597 } 598 599 /* 600 * Processing tls relocations requires having the tls offsets 601 * initialized. Prepare offsets before starting initial 602 * relocation processing. 603 */ 604 dbg("initializing initial thread local storage offsets"); 605 STAILQ_FOREACH(entry, &list_main, link) { 606 /* 607 * Allocate all the initial objects out of the static TLS 608 * block even if they didn't ask for it. 609 */ 610 allocate_tls_offset(entry->obj); 611 } 612 613 if (relocate_objects(obj_main, 614 ld_bind_now != NULL && *ld_bind_now != '\0', 615 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 616 rtld_die(); 617 618 dbg("doing copy relocations"); 619 if (do_copy_relocations(obj_main) == -1) 620 rtld_die(); 621 622 dbg("enforcing main obj relro"); 623 if (obj_enforce_relro(obj_main) == -1) 624 rtld_die(); 625 626 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 627 dump_relocations(obj_main); 628 exit (0); 629 } 630 631 /* 632 * Setup TLS for main thread. This must be done after the 633 * relocations are processed, since tls initialization section 634 * might be the subject for relocations. 635 */ 636 dbg("initializing initial thread local storage"); 637 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 638 639 dbg("initializing key program variables"); 640 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 641 set_program_var("environ", env); 642 set_program_var("__elf_aux_vector", aux); 643 644 /* Make a list of init functions to call. */ 645 objlist_init(&initlist); 646 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 647 preload_tail, &initlist); 648 649 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 650 651 map_stacks_exec(NULL); 652 ifunc_init(aux); 653 654 dbg("resolving ifuncs"); 655 if (resolve_objects_ifunc(obj_main, 656 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 657 NULL) == -1) 658 rtld_die(); 659 660 if (!obj_main->crt_no_init) { 661 /* 662 * Make sure we don't call the main program's init and fini 663 * functions for binaries linked with old crt1 which calls 664 * _init itself. 665 */ 666 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 667 obj_main->preinit_array = obj_main->init_array = 668 obj_main->fini_array = (Elf_Addr)NULL; 669 } 670 671 wlock_acquire(rtld_bind_lock, &lockstate); 672 if (obj_main->crt_no_init) 673 preinit_main(); 674 objlist_call_init(&initlist, &lockstate); 675 _r_debug_postinit(&obj_main->linkmap); 676 objlist_clear(&initlist); 677 dbg("loading filtees"); 678 TAILQ_FOREACH(obj, &obj_list, next) { 679 if (obj->marker) 680 continue; 681 if (ld_loadfltr || obj->z_loadfltr) 682 load_filtees(obj, 0, &lockstate); 683 } 684 lock_release(rtld_bind_lock, &lockstate); 685 686 dbg("transferring control to program entry point = %p", obj_main->entry); 687 688 /* Return the exit procedure and the program entry point. */ 689 *exit_proc = rtld_exit; 690 *objp = obj_main; 691 return (func_ptr_type) obj_main->entry; 692 } 693 694 void * 695 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 696 { 697 void *ptr; 698 Elf_Addr target; 699 700 ptr = (void *)make_function_pointer(def, obj); 701 target = call_ifunc_resolver(ptr); 702 return ((void *)target); 703 } 704 705 /* 706 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 707 * Changes to this function should be applied there as well. 708 */ 709 Elf_Addr 710 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 711 { 712 const Elf_Rel *rel; 713 const Elf_Sym *def; 714 const Obj_Entry *defobj; 715 Elf_Addr *where; 716 Elf_Addr target; 717 RtldLockState lockstate; 718 719 rlock_acquire(rtld_bind_lock, &lockstate); 720 if (sigsetjmp(lockstate.env, 0) != 0) 721 lock_upgrade(rtld_bind_lock, &lockstate); 722 if (obj->pltrel) 723 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 724 else 725 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 726 727 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 728 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 729 NULL, &lockstate); 730 if (def == NULL) 731 rtld_die(); 732 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 733 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 734 else 735 target = (Elf_Addr)(defobj->relocbase + def->st_value); 736 737 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 738 defobj->strtab + def->st_name, basename(obj->path), 739 (void *)target, basename(defobj->path)); 740 741 /* 742 * Write the new contents for the jmpslot. Note that depending on 743 * architecture, the value which we need to return back to the 744 * lazy binding trampoline may or may not be the target 745 * address. The value returned from reloc_jmpslot() is the value 746 * that the trampoline needs. 747 */ 748 target = reloc_jmpslot(where, target, defobj, obj, rel); 749 lock_release(rtld_bind_lock, &lockstate); 750 return target; 751 } 752 753 /* 754 * Error reporting function. Use it like printf. If formats the message 755 * into a buffer, and sets things up so that the next call to dlerror() 756 * will return the message. 757 */ 758 void 759 _rtld_error(const char *fmt, ...) 760 { 761 static char buf[512]; 762 va_list ap; 763 764 va_start(ap, fmt); 765 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 766 error_message = buf; 767 va_end(ap); 768 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 769 } 770 771 /* 772 * Return a dynamically-allocated copy of the current error message, if any. 773 */ 774 static char * 775 errmsg_save(void) 776 { 777 return error_message == NULL ? NULL : xstrdup(error_message); 778 } 779 780 /* 781 * Restore the current error message from a copy which was previously saved 782 * by errmsg_save(). The copy is freed. 783 */ 784 static void 785 errmsg_restore(char *saved_msg) 786 { 787 if (saved_msg == NULL) 788 error_message = NULL; 789 else { 790 _rtld_error("%s", saved_msg); 791 free(saved_msg); 792 } 793 } 794 795 static const char * 796 basename(const char *name) 797 { 798 const char *p = strrchr(name, '/'); 799 return p != NULL ? p + 1 : name; 800 } 801 802 static struct utsname uts; 803 804 static char * 805 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 806 const char *subst, bool may_free) 807 { 808 char *p, *p1, *res, *resp; 809 int subst_len, kw_len, subst_count, old_len, new_len; 810 811 kw_len = strlen(kw); 812 813 /* 814 * First, count the number of the keyword occurrences, to 815 * preallocate the final string. 816 */ 817 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 818 p1 = strstr(p, kw); 819 if (p1 == NULL) 820 break; 821 } 822 823 /* 824 * If the keyword is not found, just return. 825 * 826 * Return non-substituted string if resolution failed. We 827 * cannot do anything more reasonable, the failure mode of the 828 * caller is unresolved library anyway. 829 */ 830 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 831 return (may_free ? real : xstrdup(real)); 832 if (obj != NULL) 833 subst = obj->origin_path; 834 835 /* 836 * There is indeed something to substitute. Calculate the 837 * length of the resulting string, and allocate it. 838 */ 839 subst_len = strlen(subst); 840 old_len = strlen(real); 841 new_len = old_len + (subst_len - kw_len) * subst_count; 842 res = xmalloc(new_len + 1); 843 844 /* 845 * Now, execute the substitution loop. 846 */ 847 for (p = real, resp = res, *resp = '\0';;) { 848 p1 = strstr(p, kw); 849 if (p1 != NULL) { 850 /* Copy the prefix before keyword. */ 851 memcpy(resp, p, p1 - p); 852 resp += p1 - p; 853 /* Keyword replacement. */ 854 memcpy(resp, subst, subst_len); 855 resp += subst_len; 856 *resp = '\0'; 857 p = p1 + kw_len; 858 } else 859 break; 860 } 861 862 /* Copy to the end of string and finish. */ 863 strcat(resp, p); 864 if (may_free) 865 free(real); 866 return (res); 867 } 868 869 static char * 870 origin_subst(Obj_Entry *obj, char *real) 871 { 872 char *res1, *res2, *res3, *res4; 873 874 if (obj == NULL || !trust) 875 return (xstrdup(real)); 876 if (uts.sysname[0] == '\0') { 877 if (uname(&uts) != 0) { 878 _rtld_error("utsname failed: %d", errno); 879 return (NULL); 880 } 881 } 882 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 883 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 884 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 885 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 886 return (res4); 887 } 888 889 void 890 rtld_die(void) 891 { 892 const char *msg = dlerror(); 893 894 if (msg == NULL) 895 msg = "Fatal error"; 896 rtld_fdputstr(STDERR_FILENO, msg); 897 rtld_fdputchar(STDERR_FILENO, '\n'); 898 _exit(1); 899 } 900 901 /* 902 * Process a shared object's DYNAMIC section, and save the important 903 * information in its Obj_Entry structure. 904 */ 905 static void 906 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 907 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 908 { 909 const Elf_Dyn *dynp; 910 Needed_Entry **needed_tail = &obj->needed; 911 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 912 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 913 const Elf_Hashelt *hashtab; 914 const Elf32_Word *hashval; 915 Elf32_Word bkt, nmaskwords; 916 int bloom_size32; 917 int plttype = DT_REL; 918 919 *dyn_rpath = NULL; 920 *dyn_soname = NULL; 921 *dyn_runpath = NULL; 922 923 obj->bind_now = false; 924 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 925 switch (dynp->d_tag) { 926 927 case DT_REL: 928 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 929 break; 930 931 case DT_RELSZ: 932 obj->relsize = dynp->d_un.d_val; 933 break; 934 935 case DT_RELENT: 936 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 937 break; 938 939 case DT_JMPREL: 940 obj->pltrel = (const Elf_Rel *) 941 (obj->relocbase + dynp->d_un.d_ptr); 942 break; 943 944 case DT_PLTRELSZ: 945 obj->pltrelsize = dynp->d_un.d_val; 946 break; 947 948 case DT_RELA: 949 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 950 break; 951 952 case DT_RELASZ: 953 obj->relasize = dynp->d_un.d_val; 954 break; 955 956 case DT_RELAENT: 957 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 958 break; 959 960 case DT_PLTREL: 961 plttype = dynp->d_un.d_val; 962 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 963 break; 964 965 case DT_SYMTAB: 966 obj->symtab = (const Elf_Sym *) 967 (obj->relocbase + dynp->d_un.d_ptr); 968 break; 969 970 case DT_SYMENT: 971 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 972 break; 973 974 case DT_STRTAB: 975 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 976 break; 977 978 case DT_STRSZ: 979 obj->strsize = dynp->d_un.d_val; 980 break; 981 982 case DT_VERNEED: 983 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 984 dynp->d_un.d_val); 985 break; 986 987 case DT_VERNEEDNUM: 988 obj->verneednum = dynp->d_un.d_val; 989 break; 990 991 case DT_VERDEF: 992 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 993 dynp->d_un.d_val); 994 break; 995 996 case DT_VERDEFNUM: 997 obj->verdefnum = dynp->d_un.d_val; 998 break; 999 1000 case DT_VERSYM: 1001 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1002 dynp->d_un.d_val); 1003 break; 1004 1005 case DT_HASH: 1006 { 1007 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1008 dynp->d_un.d_ptr); 1009 obj->nbuckets = hashtab[0]; 1010 obj->nchains = hashtab[1]; 1011 obj->buckets = hashtab + 2; 1012 obj->chains = obj->buckets + obj->nbuckets; 1013 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1014 obj->buckets != NULL; 1015 } 1016 break; 1017 1018 case DT_GNU_HASH: 1019 { 1020 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1021 dynp->d_un.d_ptr); 1022 obj->nbuckets_gnu = hashtab[0]; 1023 obj->symndx_gnu = hashtab[1]; 1024 nmaskwords = hashtab[2]; 1025 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1026 obj->maskwords_bm_gnu = nmaskwords - 1; 1027 obj->shift2_gnu = hashtab[3]; 1028 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1029 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1030 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1031 obj->symndx_gnu; 1032 /* Number of bitmask words is required to be power of 2 */ 1033 obj->valid_hash_gnu = powerof2(nmaskwords) && 1034 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1035 } 1036 break; 1037 1038 case DT_NEEDED: 1039 if (!obj->rtld) { 1040 Needed_Entry *nep = NEW(Needed_Entry); 1041 nep->name = dynp->d_un.d_val; 1042 nep->obj = NULL; 1043 nep->next = NULL; 1044 1045 *needed_tail = nep; 1046 needed_tail = &nep->next; 1047 } 1048 break; 1049 1050 case DT_FILTER: 1051 if (!obj->rtld) { 1052 Needed_Entry *nep = NEW(Needed_Entry); 1053 nep->name = dynp->d_un.d_val; 1054 nep->obj = NULL; 1055 nep->next = NULL; 1056 1057 *needed_filtees_tail = nep; 1058 needed_filtees_tail = &nep->next; 1059 } 1060 break; 1061 1062 case DT_AUXILIARY: 1063 if (!obj->rtld) { 1064 Needed_Entry *nep = NEW(Needed_Entry); 1065 nep->name = dynp->d_un.d_val; 1066 nep->obj = NULL; 1067 nep->next = NULL; 1068 1069 *needed_aux_filtees_tail = nep; 1070 needed_aux_filtees_tail = &nep->next; 1071 } 1072 break; 1073 1074 case DT_PLTGOT: 1075 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1076 break; 1077 1078 case DT_TEXTREL: 1079 obj->textrel = true; 1080 break; 1081 1082 case DT_SYMBOLIC: 1083 obj->symbolic = true; 1084 break; 1085 1086 case DT_RPATH: 1087 /* 1088 * We have to wait until later to process this, because we 1089 * might not have gotten the address of the string table yet. 1090 */ 1091 *dyn_rpath = dynp; 1092 break; 1093 1094 case DT_SONAME: 1095 *dyn_soname = dynp; 1096 break; 1097 1098 case DT_RUNPATH: 1099 *dyn_runpath = dynp; 1100 break; 1101 1102 case DT_INIT: 1103 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1104 break; 1105 1106 case DT_PREINIT_ARRAY: 1107 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1108 break; 1109 1110 case DT_PREINIT_ARRAYSZ: 1111 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1112 break; 1113 1114 case DT_INIT_ARRAY: 1115 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1116 break; 1117 1118 case DT_INIT_ARRAYSZ: 1119 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1120 break; 1121 1122 case DT_FINI: 1123 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1124 break; 1125 1126 case DT_FINI_ARRAY: 1127 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1128 break; 1129 1130 case DT_FINI_ARRAYSZ: 1131 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1132 break; 1133 1134 /* 1135 * Don't process DT_DEBUG on MIPS as the dynamic section 1136 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1137 */ 1138 1139 #ifndef __mips__ 1140 case DT_DEBUG: 1141 if (!early) 1142 dbg("Filling in DT_DEBUG entry"); 1143 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1144 break; 1145 #endif 1146 1147 case DT_FLAGS: 1148 if (dynp->d_un.d_val & DF_ORIGIN) 1149 obj->z_origin = true; 1150 if (dynp->d_un.d_val & DF_SYMBOLIC) 1151 obj->symbolic = true; 1152 if (dynp->d_un.d_val & DF_TEXTREL) 1153 obj->textrel = true; 1154 if (dynp->d_un.d_val & DF_BIND_NOW) 1155 obj->bind_now = true; 1156 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1157 ;*/ 1158 break; 1159 #ifdef __mips__ 1160 case DT_MIPS_LOCAL_GOTNO: 1161 obj->local_gotno = dynp->d_un.d_val; 1162 break; 1163 1164 case DT_MIPS_SYMTABNO: 1165 obj->symtabno = dynp->d_un.d_val; 1166 break; 1167 1168 case DT_MIPS_GOTSYM: 1169 obj->gotsym = dynp->d_un.d_val; 1170 break; 1171 1172 case DT_MIPS_RLD_MAP: 1173 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1174 break; 1175 #endif 1176 1177 #ifdef __powerpc64__ 1178 case DT_PPC64_GLINK: 1179 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1180 break; 1181 #endif 1182 1183 case DT_FLAGS_1: 1184 if (dynp->d_un.d_val & DF_1_NOOPEN) 1185 obj->z_noopen = true; 1186 if (dynp->d_un.d_val & DF_1_ORIGIN) 1187 obj->z_origin = true; 1188 if (dynp->d_un.d_val & DF_1_GLOBAL) 1189 obj->z_global = true; 1190 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1191 obj->bind_now = true; 1192 if (dynp->d_un.d_val & DF_1_NODELETE) 1193 obj->z_nodelete = true; 1194 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1195 obj->z_loadfltr = true; 1196 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1197 obj->z_interpose = true; 1198 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1199 obj->z_nodeflib = true; 1200 break; 1201 1202 default: 1203 if (!early) { 1204 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1205 (long)dynp->d_tag); 1206 } 1207 break; 1208 } 1209 } 1210 1211 obj->traced = false; 1212 1213 if (plttype == DT_RELA) { 1214 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1215 obj->pltrel = NULL; 1216 obj->pltrelasize = obj->pltrelsize; 1217 obj->pltrelsize = 0; 1218 } 1219 1220 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1221 if (obj->valid_hash_sysv) 1222 obj->dynsymcount = obj->nchains; 1223 else if (obj->valid_hash_gnu) { 1224 obj->dynsymcount = 0; 1225 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1226 if (obj->buckets_gnu[bkt] == 0) 1227 continue; 1228 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1229 do 1230 obj->dynsymcount++; 1231 while ((*hashval++ & 1u) == 0); 1232 } 1233 obj->dynsymcount += obj->symndx_gnu; 1234 } 1235 } 1236 1237 static bool 1238 obj_resolve_origin(Obj_Entry *obj) 1239 { 1240 1241 if (obj->origin_path != NULL) 1242 return (true); 1243 obj->origin_path = xmalloc(PATH_MAX); 1244 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1245 } 1246 1247 static void 1248 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1249 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1250 { 1251 1252 if (obj->z_origin && !obj_resolve_origin(obj)) 1253 rtld_die(); 1254 1255 if (dyn_runpath != NULL) { 1256 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1257 obj->runpath = origin_subst(obj, obj->runpath); 1258 } else if (dyn_rpath != NULL) { 1259 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1260 obj->rpath = origin_subst(obj, obj->rpath); 1261 } 1262 if (dyn_soname != NULL) 1263 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1264 } 1265 1266 static void 1267 digest_dynamic(Obj_Entry *obj, int early) 1268 { 1269 const Elf_Dyn *dyn_rpath; 1270 const Elf_Dyn *dyn_soname; 1271 const Elf_Dyn *dyn_runpath; 1272 1273 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1274 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1275 } 1276 1277 /* 1278 * Process a shared object's program header. This is used only for the 1279 * main program, when the kernel has already loaded the main program 1280 * into memory before calling the dynamic linker. It creates and 1281 * returns an Obj_Entry structure. 1282 */ 1283 static Obj_Entry * 1284 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1285 { 1286 Obj_Entry *obj; 1287 const Elf_Phdr *phlimit = phdr + phnum; 1288 const Elf_Phdr *ph; 1289 Elf_Addr note_start, note_end; 1290 int nsegs = 0; 1291 1292 obj = obj_new(); 1293 for (ph = phdr; ph < phlimit; ph++) { 1294 if (ph->p_type != PT_PHDR) 1295 continue; 1296 1297 obj->phdr = phdr; 1298 obj->phsize = ph->p_memsz; 1299 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1300 break; 1301 } 1302 1303 obj->stack_flags = PF_X | PF_R | PF_W; 1304 1305 for (ph = phdr; ph < phlimit; ph++) { 1306 switch (ph->p_type) { 1307 1308 case PT_INTERP: 1309 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1310 break; 1311 1312 case PT_LOAD: 1313 if (nsegs == 0) { /* First load segment */ 1314 obj->vaddrbase = trunc_page(ph->p_vaddr); 1315 obj->mapbase = obj->vaddrbase + obj->relocbase; 1316 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1317 obj->vaddrbase; 1318 } else { /* Last load segment */ 1319 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1320 obj->vaddrbase; 1321 } 1322 nsegs++; 1323 break; 1324 1325 case PT_DYNAMIC: 1326 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1327 break; 1328 1329 case PT_TLS: 1330 obj->tlsindex = 1; 1331 obj->tlssize = ph->p_memsz; 1332 obj->tlsalign = ph->p_align; 1333 obj->tlsinitsize = ph->p_filesz; 1334 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1335 break; 1336 1337 case PT_GNU_STACK: 1338 obj->stack_flags = ph->p_flags; 1339 break; 1340 1341 case PT_GNU_RELRO: 1342 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1343 obj->relro_size = round_page(ph->p_memsz); 1344 break; 1345 1346 case PT_NOTE: 1347 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1348 note_end = note_start + ph->p_filesz; 1349 digest_notes(obj, note_start, note_end); 1350 break; 1351 } 1352 } 1353 if (nsegs < 1) { 1354 _rtld_error("%s: too few PT_LOAD segments", path); 1355 return NULL; 1356 } 1357 1358 obj->entry = entry; 1359 return obj; 1360 } 1361 1362 void 1363 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1364 { 1365 const Elf_Note *note; 1366 const char *note_name; 1367 uintptr_t p; 1368 1369 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1370 note = (const Elf_Note *)((const char *)(note + 1) + 1371 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1372 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1373 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1374 note->n_descsz != sizeof(int32_t)) 1375 continue; 1376 if (note->n_type != NT_FREEBSD_ABI_TAG && 1377 note->n_type != NT_FREEBSD_NOINIT_TAG) 1378 continue; 1379 note_name = (const char *)(note + 1); 1380 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1381 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1382 continue; 1383 switch (note->n_type) { 1384 case NT_FREEBSD_ABI_TAG: 1385 /* FreeBSD osrel note */ 1386 p = (uintptr_t)(note + 1); 1387 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1388 obj->osrel = *(const int32_t *)(p); 1389 dbg("note osrel %d", obj->osrel); 1390 break; 1391 case NT_FREEBSD_NOINIT_TAG: 1392 /* FreeBSD 'crt does not call init' note */ 1393 obj->crt_no_init = true; 1394 dbg("note crt_no_init"); 1395 break; 1396 } 1397 } 1398 } 1399 1400 static Obj_Entry * 1401 dlcheck(void *handle) 1402 { 1403 Obj_Entry *obj; 1404 1405 TAILQ_FOREACH(obj, &obj_list, next) { 1406 if (obj == (Obj_Entry *) handle) 1407 break; 1408 } 1409 1410 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1411 _rtld_error("Invalid shared object handle %p", handle); 1412 return NULL; 1413 } 1414 return obj; 1415 } 1416 1417 /* 1418 * If the given object is already in the donelist, return true. Otherwise 1419 * add the object to the list and return false. 1420 */ 1421 static bool 1422 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1423 { 1424 unsigned int i; 1425 1426 for (i = 0; i < dlp->num_used; i++) 1427 if (dlp->objs[i] == obj) 1428 return true; 1429 /* 1430 * Our donelist allocation should always be sufficient. But if 1431 * our threads locking isn't working properly, more shared objects 1432 * could have been loaded since we allocated the list. That should 1433 * never happen, but we'll handle it properly just in case it does. 1434 */ 1435 if (dlp->num_used < dlp->num_alloc) 1436 dlp->objs[dlp->num_used++] = obj; 1437 return false; 1438 } 1439 1440 /* 1441 * Hash function for symbol table lookup. Don't even think about changing 1442 * this. It is specified by the System V ABI. 1443 */ 1444 unsigned long 1445 elf_hash(const char *name) 1446 { 1447 const unsigned char *p = (const unsigned char *) name; 1448 unsigned long h = 0; 1449 unsigned long g; 1450 1451 while (*p != '\0') { 1452 h = (h << 4) + *p++; 1453 if ((g = h & 0xf0000000) != 0) 1454 h ^= g >> 24; 1455 h &= ~g; 1456 } 1457 return h; 1458 } 1459 1460 /* 1461 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1462 * unsigned in case it's implemented with a wider type. 1463 */ 1464 static uint32_t 1465 gnu_hash(const char *s) 1466 { 1467 uint32_t h; 1468 unsigned char c; 1469 1470 h = 5381; 1471 for (c = *s; c != '\0'; c = *++s) 1472 h = h * 33 + c; 1473 return (h & 0xffffffff); 1474 } 1475 1476 1477 /* 1478 * Find the library with the given name, and return its full pathname. 1479 * The returned string is dynamically allocated. Generates an error 1480 * message and returns NULL if the library cannot be found. 1481 * 1482 * If the second argument is non-NULL, then it refers to an already- 1483 * loaded shared object, whose library search path will be searched. 1484 * 1485 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1486 * descriptor (which is close-on-exec) will be passed out via the third 1487 * argument. 1488 * 1489 * The search order is: 1490 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1491 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1492 * LD_LIBRARY_PATH 1493 * DT_RUNPATH in the referencing file 1494 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1495 * from list) 1496 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1497 * 1498 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1499 */ 1500 static char * 1501 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1502 { 1503 char *pathname; 1504 char *name; 1505 bool nodeflib, objgiven; 1506 1507 objgiven = refobj != NULL; 1508 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1509 if (xname[0] != '/' && !trust) { 1510 _rtld_error("Absolute pathname required for shared object \"%s\"", 1511 xname); 1512 return NULL; 1513 } 1514 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1515 __DECONST(char *, xname))); 1516 } 1517 1518 if (libmap_disable || !objgiven || 1519 (name = lm_find(refobj->path, xname)) == NULL) 1520 name = (char *)xname; 1521 1522 dbg(" Searching for \"%s\"", name); 1523 1524 /* 1525 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1526 * back to pre-conforming behaviour if user requested so with 1527 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1528 * nodeflib. 1529 */ 1530 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1531 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1532 (refobj != NULL && 1533 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1534 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1535 (pathname = search_library_path(name, gethints(false))) != NULL || 1536 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1537 return (pathname); 1538 } else { 1539 nodeflib = objgiven ? refobj->z_nodeflib : false; 1540 if ((objgiven && 1541 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1542 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1543 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1544 (pathname = search_library_path(name, ld_library_path)) != NULL || 1545 (objgiven && 1546 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1547 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1548 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1549 (objgiven && !nodeflib && 1550 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1551 return (pathname); 1552 } 1553 1554 if (objgiven && refobj->path != NULL) { 1555 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1556 name, basename(refobj->path)); 1557 } else { 1558 _rtld_error("Shared object \"%s\" not found", name); 1559 } 1560 return NULL; 1561 } 1562 1563 /* 1564 * Given a symbol number in a referencing object, find the corresponding 1565 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1566 * no definition was found. Returns a pointer to the Obj_Entry of the 1567 * defining object via the reference parameter DEFOBJ_OUT. 1568 */ 1569 const Elf_Sym * 1570 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1571 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1572 RtldLockState *lockstate) 1573 { 1574 const Elf_Sym *ref; 1575 const Elf_Sym *def; 1576 const Obj_Entry *defobj; 1577 SymLook req; 1578 const char *name; 1579 int res; 1580 1581 /* 1582 * If we have already found this symbol, get the information from 1583 * the cache. 1584 */ 1585 if (symnum >= refobj->dynsymcount) 1586 return NULL; /* Bad object */ 1587 if (cache != NULL && cache[symnum].sym != NULL) { 1588 *defobj_out = cache[symnum].obj; 1589 return cache[symnum].sym; 1590 } 1591 1592 ref = refobj->symtab + symnum; 1593 name = refobj->strtab + ref->st_name; 1594 def = NULL; 1595 defobj = NULL; 1596 1597 /* 1598 * We don't have to do a full scale lookup if the symbol is local. 1599 * We know it will bind to the instance in this load module; to 1600 * which we already have a pointer (ie ref). By not doing a lookup, 1601 * we not only improve performance, but it also avoids unresolvable 1602 * symbols when local symbols are not in the hash table. This has 1603 * been seen with the ia64 toolchain. 1604 */ 1605 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1606 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1607 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1608 symnum); 1609 } 1610 symlook_init(&req, name); 1611 req.flags = flags; 1612 req.ventry = fetch_ventry(refobj, symnum); 1613 req.lockstate = lockstate; 1614 res = symlook_default(&req, refobj); 1615 if (res == 0) { 1616 def = req.sym_out; 1617 defobj = req.defobj_out; 1618 } 1619 } else { 1620 def = ref; 1621 defobj = refobj; 1622 } 1623 1624 /* 1625 * If we found no definition and the reference is weak, treat the 1626 * symbol as having the value zero. 1627 */ 1628 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1629 def = &sym_zero; 1630 defobj = obj_main; 1631 } 1632 1633 if (def != NULL) { 1634 *defobj_out = defobj; 1635 /* Record the information in the cache to avoid subsequent lookups. */ 1636 if (cache != NULL) { 1637 cache[symnum].sym = def; 1638 cache[symnum].obj = defobj; 1639 } 1640 } else { 1641 if (refobj != &obj_rtld) 1642 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1643 } 1644 return def; 1645 } 1646 1647 /* 1648 * Return the search path from the ldconfig hints file, reading it if 1649 * necessary. If nostdlib is true, then the default search paths are 1650 * not added to result. 1651 * 1652 * Returns NULL if there are problems with the hints file, 1653 * or if the search path there is empty. 1654 */ 1655 static const char * 1656 gethints(bool nostdlib) 1657 { 1658 static char *hints, *filtered_path; 1659 static struct elfhints_hdr hdr; 1660 struct fill_search_info_args sargs, hargs; 1661 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1662 struct dl_serpath *SLPpath, *hintpath; 1663 char *p; 1664 struct stat hint_stat; 1665 unsigned int SLPndx, hintndx, fndx, fcount; 1666 int fd; 1667 size_t flen; 1668 uint32_t dl; 1669 bool skip; 1670 1671 /* First call, read the hints file */ 1672 if (hints == NULL) { 1673 /* Keep from trying again in case the hints file is bad. */ 1674 hints = ""; 1675 1676 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1677 return (NULL); 1678 1679 /* 1680 * Check of hdr.dirlistlen value against type limit 1681 * intends to pacify static analyzers. Further 1682 * paranoia leads to checks that dirlist is fully 1683 * contained in the file range. 1684 */ 1685 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1686 hdr.magic != ELFHINTS_MAGIC || 1687 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1688 fstat(fd, &hint_stat) == -1) { 1689 cleanup1: 1690 close(fd); 1691 hdr.dirlistlen = 0; 1692 return (NULL); 1693 } 1694 dl = hdr.strtab; 1695 if (dl + hdr.dirlist < dl) 1696 goto cleanup1; 1697 dl += hdr.dirlist; 1698 if (dl + hdr.dirlistlen < dl) 1699 goto cleanup1; 1700 dl += hdr.dirlistlen; 1701 if (dl > hint_stat.st_size) 1702 goto cleanup1; 1703 p = xmalloc(hdr.dirlistlen + 1); 1704 1705 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1706 read(fd, p, hdr.dirlistlen + 1) != 1707 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1708 free(p); 1709 goto cleanup1; 1710 } 1711 hints = p; 1712 close(fd); 1713 } 1714 1715 /* 1716 * If caller agreed to receive list which includes the default 1717 * paths, we are done. Otherwise, if we still did not 1718 * calculated filtered result, do it now. 1719 */ 1720 if (!nostdlib) 1721 return (hints[0] != '\0' ? hints : NULL); 1722 if (filtered_path != NULL) 1723 goto filt_ret; 1724 1725 /* 1726 * Obtain the list of all configured search paths, and the 1727 * list of the default paths. 1728 * 1729 * First estimate the size of the results. 1730 */ 1731 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1732 smeta.dls_cnt = 0; 1733 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1734 hmeta.dls_cnt = 0; 1735 1736 sargs.request = RTLD_DI_SERINFOSIZE; 1737 sargs.serinfo = &smeta; 1738 hargs.request = RTLD_DI_SERINFOSIZE; 1739 hargs.serinfo = &hmeta; 1740 1741 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1742 path_enumerate(hints, fill_search_info, &hargs); 1743 1744 SLPinfo = xmalloc(smeta.dls_size); 1745 hintinfo = xmalloc(hmeta.dls_size); 1746 1747 /* 1748 * Next fetch both sets of paths. 1749 */ 1750 sargs.request = RTLD_DI_SERINFO; 1751 sargs.serinfo = SLPinfo; 1752 sargs.serpath = &SLPinfo->dls_serpath[0]; 1753 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1754 1755 hargs.request = RTLD_DI_SERINFO; 1756 hargs.serinfo = hintinfo; 1757 hargs.serpath = &hintinfo->dls_serpath[0]; 1758 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1759 1760 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1761 path_enumerate(hints, fill_search_info, &hargs); 1762 1763 /* 1764 * Now calculate the difference between two sets, by excluding 1765 * standard paths from the full set. 1766 */ 1767 fndx = 0; 1768 fcount = 0; 1769 filtered_path = xmalloc(hdr.dirlistlen + 1); 1770 hintpath = &hintinfo->dls_serpath[0]; 1771 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1772 skip = false; 1773 SLPpath = &SLPinfo->dls_serpath[0]; 1774 /* 1775 * Check each standard path against current. 1776 */ 1777 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1778 /* matched, skip the path */ 1779 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1780 skip = true; 1781 break; 1782 } 1783 } 1784 if (skip) 1785 continue; 1786 /* 1787 * Not matched against any standard path, add the path 1788 * to result. Separate consequtive paths with ':'. 1789 */ 1790 if (fcount > 0) { 1791 filtered_path[fndx] = ':'; 1792 fndx++; 1793 } 1794 fcount++; 1795 flen = strlen(hintpath->dls_name); 1796 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1797 fndx += flen; 1798 } 1799 filtered_path[fndx] = '\0'; 1800 1801 free(SLPinfo); 1802 free(hintinfo); 1803 1804 filt_ret: 1805 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1806 } 1807 1808 static void 1809 init_dag(Obj_Entry *root) 1810 { 1811 const Needed_Entry *needed; 1812 const Objlist_Entry *elm; 1813 DoneList donelist; 1814 1815 if (root->dag_inited) 1816 return; 1817 donelist_init(&donelist); 1818 1819 /* Root object belongs to own DAG. */ 1820 objlist_push_tail(&root->dldags, root); 1821 objlist_push_tail(&root->dagmembers, root); 1822 donelist_check(&donelist, root); 1823 1824 /* 1825 * Add dependencies of root object to DAG in breadth order 1826 * by exploiting the fact that each new object get added 1827 * to the tail of the dagmembers list. 1828 */ 1829 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1830 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1831 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1832 continue; 1833 objlist_push_tail(&needed->obj->dldags, root); 1834 objlist_push_tail(&root->dagmembers, needed->obj); 1835 } 1836 } 1837 root->dag_inited = true; 1838 } 1839 1840 static void 1841 init_marker(Obj_Entry *marker) 1842 { 1843 1844 bzero(marker, sizeof(*marker)); 1845 marker->marker = true; 1846 } 1847 1848 Obj_Entry * 1849 globallist_curr(const Obj_Entry *obj) 1850 { 1851 1852 for (;;) { 1853 if (obj == NULL) 1854 return (NULL); 1855 if (!obj->marker) 1856 return (__DECONST(Obj_Entry *, obj)); 1857 obj = TAILQ_PREV(obj, obj_entry_q, next); 1858 } 1859 } 1860 1861 Obj_Entry * 1862 globallist_next(const Obj_Entry *obj) 1863 { 1864 1865 for (;;) { 1866 obj = TAILQ_NEXT(obj, next); 1867 if (obj == NULL) 1868 return (NULL); 1869 if (!obj->marker) 1870 return (__DECONST(Obj_Entry *, obj)); 1871 } 1872 } 1873 1874 /* Prevent the object from being unmapped while the bind lock is dropped. */ 1875 static void 1876 hold_object(Obj_Entry *obj) 1877 { 1878 1879 obj->holdcount++; 1880 } 1881 1882 static void 1883 unhold_object(Obj_Entry *obj) 1884 { 1885 1886 assert(obj->holdcount > 0); 1887 if (--obj->holdcount == 0 && obj->unholdfree) 1888 release_object(obj); 1889 } 1890 1891 static void 1892 process_z(Obj_Entry *root) 1893 { 1894 const Objlist_Entry *elm; 1895 Obj_Entry *obj; 1896 1897 /* 1898 * Walk over object DAG and process every dependent object 1899 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1900 * to grow their own DAG. 1901 * 1902 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1903 * symlook_global() to work. 1904 * 1905 * For DF_1_NODELETE, the DAG should have its reference upped. 1906 */ 1907 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1908 obj = elm->obj; 1909 if (obj == NULL) 1910 continue; 1911 if (obj->z_nodelete && !obj->ref_nodel) { 1912 dbg("obj %s -z nodelete", obj->path); 1913 init_dag(obj); 1914 ref_dag(obj); 1915 obj->ref_nodel = true; 1916 } 1917 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1918 dbg("obj %s -z global", obj->path); 1919 objlist_push_tail(&list_global, obj); 1920 init_dag(obj); 1921 } 1922 } 1923 } 1924 /* 1925 * Initialize the dynamic linker. The argument is the address at which 1926 * the dynamic linker has been mapped into memory. The primary task of 1927 * this function is to relocate the dynamic linker. 1928 */ 1929 static void 1930 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1931 { 1932 Obj_Entry objtmp; /* Temporary rtld object */ 1933 const Elf_Ehdr *ehdr; 1934 const Elf_Dyn *dyn_rpath; 1935 const Elf_Dyn *dyn_soname; 1936 const Elf_Dyn *dyn_runpath; 1937 1938 #ifdef RTLD_INIT_PAGESIZES_EARLY 1939 /* The page size is required by the dynamic memory allocator. */ 1940 init_pagesizes(aux_info); 1941 #endif 1942 1943 /* 1944 * Conjure up an Obj_Entry structure for the dynamic linker. 1945 * 1946 * The "path" member can't be initialized yet because string constants 1947 * cannot yet be accessed. Below we will set it correctly. 1948 */ 1949 memset(&objtmp, 0, sizeof(objtmp)); 1950 objtmp.path = NULL; 1951 objtmp.rtld = true; 1952 objtmp.mapbase = mapbase; 1953 #ifdef PIC 1954 objtmp.relocbase = mapbase; 1955 #endif 1956 1957 objtmp.dynamic = rtld_dynamic(&objtmp); 1958 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1959 assert(objtmp.needed == NULL); 1960 #if !defined(__mips__) 1961 /* MIPS has a bogus DT_TEXTREL. */ 1962 assert(!objtmp.textrel); 1963 #endif 1964 /* 1965 * Temporarily put the dynamic linker entry into the object list, so 1966 * that symbols can be found. 1967 */ 1968 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1969 1970 ehdr = (Elf_Ehdr *)mapbase; 1971 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1972 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1973 1974 /* Initialize the object list. */ 1975 TAILQ_INIT(&obj_list); 1976 1977 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1978 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1979 1980 #ifndef RTLD_INIT_PAGESIZES_EARLY 1981 /* The page size is required by the dynamic memory allocator. */ 1982 init_pagesizes(aux_info); 1983 #endif 1984 1985 if (aux_info[AT_OSRELDATE] != NULL) 1986 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1987 1988 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1989 1990 /* Replace the path with a dynamically allocated copy. */ 1991 obj_rtld.path = xstrdup(ld_path_rtld); 1992 1993 r_debug.r_brk = r_debug_state; 1994 r_debug.r_state = RT_CONSISTENT; 1995 } 1996 1997 /* 1998 * Retrieve the array of supported page sizes. The kernel provides the page 1999 * sizes in increasing order. 2000 */ 2001 static void 2002 init_pagesizes(Elf_Auxinfo **aux_info) 2003 { 2004 static size_t psa[MAXPAGESIZES]; 2005 int mib[2]; 2006 size_t len, size; 2007 2008 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2009 NULL) { 2010 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2011 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2012 } else { 2013 len = 2; 2014 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2015 size = sizeof(psa); 2016 else { 2017 /* As a fallback, retrieve the base page size. */ 2018 size = sizeof(psa[0]); 2019 if (aux_info[AT_PAGESZ] != NULL) { 2020 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2021 goto psa_filled; 2022 } else { 2023 mib[0] = CTL_HW; 2024 mib[1] = HW_PAGESIZE; 2025 len = 2; 2026 } 2027 } 2028 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2029 _rtld_error("sysctl for hw.pagesize(s) failed"); 2030 rtld_die(); 2031 } 2032 psa_filled: 2033 pagesizes = psa; 2034 } 2035 npagesizes = size / sizeof(pagesizes[0]); 2036 /* Discard any invalid entries at the end of the array. */ 2037 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2038 npagesizes--; 2039 } 2040 2041 /* 2042 * Add the init functions from a needed object list (and its recursive 2043 * needed objects) to "list". This is not used directly; it is a helper 2044 * function for initlist_add_objects(). The write lock must be held 2045 * when this function is called. 2046 */ 2047 static void 2048 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2049 { 2050 /* Recursively process the successor needed objects. */ 2051 if (needed->next != NULL) 2052 initlist_add_neededs(needed->next, list); 2053 2054 /* Process the current needed object. */ 2055 if (needed->obj != NULL) 2056 initlist_add_objects(needed->obj, needed->obj, list); 2057 } 2058 2059 /* 2060 * Scan all of the DAGs rooted in the range of objects from "obj" to 2061 * "tail" and add their init functions to "list". This recurses over 2062 * the DAGs and ensure the proper init ordering such that each object's 2063 * needed libraries are initialized before the object itself. At the 2064 * same time, this function adds the objects to the global finalization 2065 * list "list_fini" in the opposite order. The write lock must be 2066 * held when this function is called. 2067 */ 2068 static void 2069 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2070 { 2071 Obj_Entry *nobj; 2072 2073 if (obj->init_scanned || obj->init_done) 2074 return; 2075 obj->init_scanned = true; 2076 2077 /* Recursively process the successor objects. */ 2078 nobj = globallist_next(obj); 2079 if (nobj != NULL && obj != tail) 2080 initlist_add_objects(nobj, tail, list); 2081 2082 /* Recursively process the needed objects. */ 2083 if (obj->needed != NULL) 2084 initlist_add_neededs(obj->needed, list); 2085 if (obj->needed_filtees != NULL) 2086 initlist_add_neededs(obj->needed_filtees, list); 2087 if (obj->needed_aux_filtees != NULL) 2088 initlist_add_neededs(obj->needed_aux_filtees, list); 2089 2090 /* Add the object to the init list. */ 2091 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2092 obj->init_array != (Elf_Addr)NULL) 2093 objlist_push_tail(list, obj); 2094 2095 /* Add the object to the global fini list in the reverse order. */ 2096 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2097 && !obj->on_fini_list) { 2098 objlist_push_head(&list_fini, obj); 2099 obj->on_fini_list = true; 2100 } 2101 } 2102 2103 #ifndef FPTR_TARGET 2104 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2105 #endif 2106 2107 static void 2108 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2109 { 2110 Needed_Entry *needed, *needed1; 2111 2112 for (needed = n; needed != NULL; needed = needed->next) { 2113 if (needed->obj != NULL) { 2114 dlclose_locked(needed->obj, lockstate); 2115 needed->obj = NULL; 2116 } 2117 } 2118 for (needed = n; needed != NULL; needed = needed1) { 2119 needed1 = needed->next; 2120 free(needed); 2121 } 2122 } 2123 2124 static void 2125 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2126 { 2127 2128 free_needed_filtees(obj->needed_filtees, lockstate); 2129 obj->needed_filtees = NULL; 2130 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2131 obj->needed_aux_filtees = NULL; 2132 obj->filtees_loaded = false; 2133 } 2134 2135 static void 2136 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2137 RtldLockState *lockstate) 2138 { 2139 2140 for (; needed != NULL; needed = needed->next) { 2141 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2142 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2143 RTLD_LOCAL, lockstate); 2144 } 2145 } 2146 2147 static void 2148 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2149 { 2150 2151 lock_restart_for_upgrade(lockstate); 2152 if (!obj->filtees_loaded) { 2153 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2154 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2155 obj->filtees_loaded = true; 2156 } 2157 } 2158 2159 static int 2160 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2161 { 2162 Obj_Entry *obj1; 2163 2164 for (; needed != NULL; needed = needed->next) { 2165 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2166 flags & ~RTLD_LO_NOLOAD); 2167 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2168 return (-1); 2169 } 2170 return (0); 2171 } 2172 2173 /* 2174 * Given a shared object, traverse its list of needed objects, and load 2175 * each of them. Returns 0 on success. Generates an error message and 2176 * returns -1 on failure. 2177 */ 2178 static int 2179 load_needed_objects(Obj_Entry *first, int flags) 2180 { 2181 Obj_Entry *obj; 2182 2183 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2184 if (obj->marker) 2185 continue; 2186 if (process_needed(obj, obj->needed, flags) == -1) 2187 return (-1); 2188 } 2189 return (0); 2190 } 2191 2192 static int 2193 load_preload_objects(void) 2194 { 2195 char *p = ld_preload; 2196 Obj_Entry *obj; 2197 static const char delim[] = " \t:;"; 2198 2199 if (p == NULL) 2200 return 0; 2201 2202 p += strspn(p, delim); 2203 while (*p != '\0') { 2204 size_t len = strcspn(p, delim); 2205 char savech; 2206 2207 savech = p[len]; 2208 p[len] = '\0'; 2209 obj = load_object(p, -1, NULL, 0); 2210 if (obj == NULL) 2211 return -1; /* XXX - cleanup */ 2212 obj->z_interpose = true; 2213 p[len] = savech; 2214 p += len; 2215 p += strspn(p, delim); 2216 } 2217 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2218 return 0; 2219 } 2220 2221 static const char * 2222 printable_path(const char *path) 2223 { 2224 2225 return (path == NULL ? "<unknown>" : path); 2226 } 2227 2228 /* 2229 * Load a shared object into memory, if it is not already loaded. The 2230 * object may be specified by name or by user-supplied file descriptor 2231 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2232 * duplicate is. 2233 * 2234 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2235 * on failure. 2236 */ 2237 static Obj_Entry * 2238 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2239 { 2240 Obj_Entry *obj; 2241 int fd; 2242 struct stat sb; 2243 char *path; 2244 2245 fd = -1; 2246 if (name != NULL) { 2247 TAILQ_FOREACH(obj, &obj_list, next) { 2248 if (obj->marker || obj->doomed) 2249 continue; 2250 if (object_match_name(obj, name)) 2251 return (obj); 2252 } 2253 2254 path = find_library(name, refobj, &fd); 2255 if (path == NULL) 2256 return (NULL); 2257 } else 2258 path = NULL; 2259 2260 if (fd >= 0) { 2261 /* 2262 * search_library_pathfds() opens a fresh file descriptor for the 2263 * library, so there is no need to dup(). 2264 */ 2265 } else if (fd_u == -1) { 2266 /* 2267 * If we didn't find a match by pathname, or the name is not 2268 * supplied, open the file and check again by device and inode. 2269 * This avoids false mismatches caused by multiple links or ".." 2270 * in pathnames. 2271 * 2272 * To avoid a race, we open the file and use fstat() rather than 2273 * using stat(). 2274 */ 2275 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2276 _rtld_error("Cannot open \"%s\"", path); 2277 free(path); 2278 return (NULL); 2279 } 2280 } else { 2281 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2282 if (fd == -1) { 2283 _rtld_error("Cannot dup fd"); 2284 free(path); 2285 return (NULL); 2286 } 2287 } 2288 if (fstat(fd, &sb) == -1) { 2289 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2290 close(fd); 2291 free(path); 2292 return NULL; 2293 } 2294 TAILQ_FOREACH(obj, &obj_list, next) { 2295 if (obj->marker || obj->doomed) 2296 continue; 2297 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2298 break; 2299 } 2300 if (obj != NULL && name != NULL) { 2301 object_add_name(obj, name); 2302 free(path); 2303 close(fd); 2304 return obj; 2305 } 2306 if (flags & RTLD_LO_NOLOAD) { 2307 free(path); 2308 close(fd); 2309 return (NULL); 2310 } 2311 2312 /* First use of this object, so we must map it in */ 2313 obj = do_load_object(fd, name, path, &sb, flags); 2314 if (obj == NULL) 2315 free(path); 2316 close(fd); 2317 2318 return obj; 2319 } 2320 2321 static Obj_Entry * 2322 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2323 int flags) 2324 { 2325 Obj_Entry *obj; 2326 struct statfs fs; 2327 2328 /* 2329 * but first, make sure that environment variables haven't been 2330 * used to circumvent the noexec flag on a filesystem. 2331 */ 2332 if (dangerous_ld_env) { 2333 if (fstatfs(fd, &fs) != 0) { 2334 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2335 return NULL; 2336 } 2337 if (fs.f_flags & MNT_NOEXEC) { 2338 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2339 return NULL; 2340 } 2341 } 2342 dbg("loading \"%s\"", printable_path(path)); 2343 obj = map_object(fd, printable_path(path), sbp); 2344 if (obj == NULL) 2345 return NULL; 2346 2347 /* 2348 * If DT_SONAME is present in the object, digest_dynamic2 already 2349 * added it to the object names. 2350 */ 2351 if (name != NULL) 2352 object_add_name(obj, name); 2353 obj->path = path; 2354 digest_dynamic(obj, 0); 2355 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2356 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2357 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2358 RTLD_LO_DLOPEN) { 2359 dbg("refusing to load non-loadable \"%s\"", obj->path); 2360 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2361 munmap(obj->mapbase, obj->mapsize); 2362 obj_free(obj); 2363 return (NULL); 2364 } 2365 2366 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2367 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2368 obj_count++; 2369 obj_loads++; 2370 linkmap_add(obj); /* for GDB & dlinfo() */ 2371 max_stack_flags |= obj->stack_flags; 2372 2373 dbg(" %p .. %p: %s", obj->mapbase, 2374 obj->mapbase + obj->mapsize - 1, obj->path); 2375 if (obj->textrel) 2376 dbg(" WARNING: %s has impure text", obj->path); 2377 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2378 obj->path); 2379 2380 return obj; 2381 } 2382 2383 static Obj_Entry * 2384 obj_from_addr(const void *addr) 2385 { 2386 Obj_Entry *obj; 2387 2388 TAILQ_FOREACH(obj, &obj_list, next) { 2389 if (obj->marker) 2390 continue; 2391 if (addr < (void *) obj->mapbase) 2392 continue; 2393 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2394 return obj; 2395 } 2396 return NULL; 2397 } 2398 2399 static void 2400 preinit_main(void) 2401 { 2402 Elf_Addr *preinit_addr; 2403 int index; 2404 2405 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2406 if (preinit_addr == NULL) 2407 return; 2408 2409 for (index = 0; index < obj_main->preinit_array_num; index++) { 2410 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2411 dbg("calling preinit function for %s at %p", obj_main->path, 2412 (void *)preinit_addr[index]); 2413 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2414 0, 0, obj_main->path); 2415 call_init_pointer(obj_main, preinit_addr[index]); 2416 } 2417 } 2418 } 2419 2420 /* 2421 * Call the finalization functions for each of the objects in "list" 2422 * belonging to the DAG of "root" and referenced once. If NULL "root" 2423 * is specified, every finalization function will be called regardless 2424 * of the reference count and the list elements won't be freed. All of 2425 * the objects are expected to have non-NULL fini functions. 2426 */ 2427 static void 2428 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2429 { 2430 Objlist_Entry *elm; 2431 char *saved_msg; 2432 Elf_Addr *fini_addr; 2433 int index; 2434 2435 assert(root == NULL || root->refcount == 1); 2436 2437 if (root != NULL) 2438 root->doomed = true; 2439 2440 /* 2441 * Preserve the current error message since a fini function might 2442 * call into the dynamic linker and overwrite it. 2443 */ 2444 saved_msg = errmsg_save(); 2445 do { 2446 STAILQ_FOREACH(elm, list, link) { 2447 if (root != NULL && (elm->obj->refcount != 1 || 2448 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2449 continue; 2450 /* Remove object from fini list to prevent recursive invocation. */ 2451 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2452 /* Ensure that new references cannot be acquired. */ 2453 elm->obj->doomed = true; 2454 2455 hold_object(elm->obj); 2456 lock_release(rtld_bind_lock, lockstate); 2457 /* 2458 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2459 * When this happens, DT_FINI_ARRAY is processed first. 2460 */ 2461 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2462 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2463 for (index = elm->obj->fini_array_num - 1; index >= 0; 2464 index--) { 2465 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2466 dbg("calling fini function for %s at %p", 2467 elm->obj->path, (void *)fini_addr[index]); 2468 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2469 (void *)fini_addr[index], 0, 0, elm->obj->path); 2470 call_initfini_pointer(elm->obj, fini_addr[index]); 2471 } 2472 } 2473 } 2474 if (elm->obj->fini != (Elf_Addr)NULL) { 2475 dbg("calling fini function for %s at %p", elm->obj->path, 2476 (void *)elm->obj->fini); 2477 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2478 0, 0, elm->obj->path); 2479 call_initfini_pointer(elm->obj, elm->obj->fini); 2480 } 2481 wlock_acquire(rtld_bind_lock, lockstate); 2482 unhold_object(elm->obj); 2483 /* No need to free anything if process is going down. */ 2484 if (root != NULL) 2485 free(elm); 2486 /* 2487 * We must restart the list traversal after every fini call 2488 * because a dlclose() call from the fini function or from 2489 * another thread might have modified the reference counts. 2490 */ 2491 break; 2492 } 2493 } while (elm != NULL); 2494 errmsg_restore(saved_msg); 2495 } 2496 2497 /* 2498 * Call the initialization functions for each of the objects in 2499 * "list". All of the objects are expected to have non-NULL init 2500 * functions. 2501 */ 2502 static void 2503 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2504 { 2505 Objlist_Entry *elm; 2506 Obj_Entry *obj; 2507 char *saved_msg; 2508 Elf_Addr *init_addr; 2509 int index; 2510 2511 /* 2512 * Clean init_scanned flag so that objects can be rechecked and 2513 * possibly initialized earlier if any of vectors called below 2514 * cause the change by using dlopen. 2515 */ 2516 TAILQ_FOREACH(obj, &obj_list, next) { 2517 if (obj->marker) 2518 continue; 2519 obj->init_scanned = false; 2520 } 2521 2522 /* 2523 * Preserve the current error message since an init function might 2524 * call into the dynamic linker and overwrite it. 2525 */ 2526 saved_msg = errmsg_save(); 2527 STAILQ_FOREACH(elm, list, link) { 2528 if (elm->obj->init_done) /* Initialized early. */ 2529 continue; 2530 /* 2531 * Race: other thread might try to use this object before current 2532 * one completes the initialization. Not much can be done here 2533 * without better locking. 2534 */ 2535 elm->obj->init_done = true; 2536 hold_object(elm->obj); 2537 lock_release(rtld_bind_lock, lockstate); 2538 2539 /* 2540 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2541 * When this happens, DT_INIT is processed first. 2542 */ 2543 if (elm->obj->init != (Elf_Addr)NULL) { 2544 dbg("calling init function for %s at %p", elm->obj->path, 2545 (void *)elm->obj->init); 2546 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2547 0, 0, elm->obj->path); 2548 call_initfini_pointer(elm->obj, elm->obj->init); 2549 } 2550 init_addr = (Elf_Addr *)elm->obj->init_array; 2551 if (init_addr != NULL) { 2552 for (index = 0; index < elm->obj->init_array_num; index++) { 2553 if (init_addr[index] != 0 && init_addr[index] != 1) { 2554 dbg("calling init function for %s at %p", elm->obj->path, 2555 (void *)init_addr[index]); 2556 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2557 (void *)init_addr[index], 0, 0, elm->obj->path); 2558 call_init_pointer(elm->obj, init_addr[index]); 2559 } 2560 } 2561 } 2562 wlock_acquire(rtld_bind_lock, lockstate); 2563 unhold_object(elm->obj); 2564 } 2565 errmsg_restore(saved_msg); 2566 } 2567 2568 static void 2569 objlist_clear(Objlist *list) 2570 { 2571 Objlist_Entry *elm; 2572 2573 while (!STAILQ_EMPTY(list)) { 2574 elm = STAILQ_FIRST(list); 2575 STAILQ_REMOVE_HEAD(list, link); 2576 free(elm); 2577 } 2578 } 2579 2580 static Objlist_Entry * 2581 objlist_find(Objlist *list, const Obj_Entry *obj) 2582 { 2583 Objlist_Entry *elm; 2584 2585 STAILQ_FOREACH(elm, list, link) 2586 if (elm->obj == obj) 2587 return elm; 2588 return NULL; 2589 } 2590 2591 static void 2592 objlist_init(Objlist *list) 2593 { 2594 STAILQ_INIT(list); 2595 } 2596 2597 static void 2598 objlist_push_head(Objlist *list, Obj_Entry *obj) 2599 { 2600 Objlist_Entry *elm; 2601 2602 elm = NEW(Objlist_Entry); 2603 elm->obj = obj; 2604 STAILQ_INSERT_HEAD(list, elm, link); 2605 } 2606 2607 static void 2608 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2609 { 2610 Objlist_Entry *elm; 2611 2612 elm = NEW(Objlist_Entry); 2613 elm->obj = obj; 2614 STAILQ_INSERT_TAIL(list, elm, link); 2615 } 2616 2617 static void 2618 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2619 { 2620 Objlist_Entry *elm, *listelm; 2621 2622 STAILQ_FOREACH(listelm, list, link) { 2623 if (listelm->obj == listobj) 2624 break; 2625 } 2626 elm = NEW(Objlist_Entry); 2627 elm->obj = obj; 2628 if (listelm != NULL) 2629 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2630 else 2631 STAILQ_INSERT_TAIL(list, elm, link); 2632 } 2633 2634 static void 2635 objlist_remove(Objlist *list, Obj_Entry *obj) 2636 { 2637 Objlist_Entry *elm; 2638 2639 if ((elm = objlist_find(list, obj)) != NULL) { 2640 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2641 free(elm); 2642 } 2643 } 2644 2645 /* 2646 * Relocate dag rooted in the specified object. 2647 * Returns 0 on success, or -1 on failure. 2648 */ 2649 2650 static int 2651 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2652 int flags, RtldLockState *lockstate) 2653 { 2654 Objlist_Entry *elm; 2655 int error; 2656 2657 error = 0; 2658 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2659 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2660 lockstate); 2661 if (error == -1) 2662 break; 2663 } 2664 return (error); 2665 } 2666 2667 /* 2668 * Prepare for, or clean after, relocating an object marked with 2669 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2670 * segments are remapped read-write. After relocations are done, the 2671 * segment's permissions are returned back to the modes specified in 2672 * the phdrs. If any relocation happened, or always for wired 2673 * program, COW is triggered. 2674 */ 2675 static int 2676 reloc_textrel_prot(Obj_Entry *obj, bool before) 2677 { 2678 const Elf_Phdr *ph; 2679 void *base; 2680 size_t l, sz; 2681 int prot; 2682 2683 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2684 l--, ph++) { 2685 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2686 continue; 2687 base = obj->relocbase + trunc_page(ph->p_vaddr); 2688 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2689 trunc_page(ph->p_vaddr); 2690 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2691 if (mprotect(base, sz, prot) == -1) { 2692 _rtld_error("%s: Cannot write-%sable text segment: %s", 2693 obj->path, before ? "en" : "dis", 2694 rtld_strerror(errno)); 2695 return (-1); 2696 } 2697 } 2698 return (0); 2699 } 2700 2701 /* 2702 * Relocate single object. 2703 * Returns 0 on success, or -1 on failure. 2704 */ 2705 static int 2706 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2707 int flags, RtldLockState *lockstate) 2708 { 2709 2710 if (obj->relocated) 2711 return (0); 2712 obj->relocated = true; 2713 if (obj != rtldobj) 2714 dbg("relocating \"%s\"", obj->path); 2715 2716 if (obj->symtab == NULL || obj->strtab == NULL || 2717 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2718 _rtld_error("%s: Shared object has no run-time symbol table", 2719 obj->path); 2720 return (-1); 2721 } 2722 2723 /* There are relocations to the write-protected text segment. */ 2724 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2725 return (-1); 2726 2727 /* Process the non-PLT non-IFUNC relocations. */ 2728 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2729 return (-1); 2730 2731 /* Re-protected the text segment. */ 2732 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2733 return (-1); 2734 2735 /* Set the special PLT or GOT entries. */ 2736 init_pltgot(obj); 2737 2738 /* Process the PLT relocations. */ 2739 if (reloc_plt(obj) == -1) 2740 return (-1); 2741 /* Relocate the jump slots if we are doing immediate binding. */ 2742 if (obj->bind_now || bind_now) 2743 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2744 return (-1); 2745 2746 /* 2747 * Process the non-PLT IFUNC relocations. The relocations are 2748 * processed in two phases, because IFUNC resolvers may 2749 * reference other symbols, which must be readily processed 2750 * before resolvers are called. 2751 */ 2752 if (obj->non_plt_gnu_ifunc && 2753 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2754 return (-1); 2755 2756 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2757 return (-1); 2758 2759 /* 2760 * Set up the magic number and version in the Obj_Entry. These 2761 * were checked in the crt1.o from the original ElfKit, so we 2762 * set them for backward compatibility. 2763 */ 2764 obj->magic = RTLD_MAGIC; 2765 obj->version = RTLD_VERSION; 2766 2767 return (0); 2768 } 2769 2770 /* 2771 * Relocate newly-loaded shared objects. The argument is a pointer to 2772 * the Obj_Entry for the first such object. All objects from the first 2773 * to the end of the list of objects are relocated. Returns 0 on success, 2774 * or -1 on failure. 2775 */ 2776 static int 2777 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2778 int flags, RtldLockState *lockstate) 2779 { 2780 Obj_Entry *obj; 2781 int error; 2782 2783 for (error = 0, obj = first; obj != NULL; 2784 obj = TAILQ_NEXT(obj, next)) { 2785 if (obj->marker) 2786 continue; 2787 error = relocate_object(obj, bind_now, rtldobj, flags, 2788 lockstate); 2789 if (error == -1) 2790 break; 2791 } 2792 return (error); 2793 } 2794 2795 /* 2796 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2797 * referencing STT_GNU_IFUNC symbols is postponed till the other 2798 * relocations are done. The indirect functions specified as 2799 * ifunc are allowed to call other symbols, so we need to have 2800 * objects relocated before asking for resolution from indirects. 2801 * 2802 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2803 * instead of the usual lazy handling of PLT slots. It is 2804 * consistent with how GNU does it. 2805 */ 2806 static int 2807 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2808 RtldLockState *lockstate) 2809 { 2810 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2811 return (-1); 2812 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2813 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2814 return (-1); 2815 return (0); 2816 } 2817 2818 static int 2819 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2820 RtldLockState *lockstate) 2821 { 2822 Obj_Entry *obj; 2823 2824 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2825 if (obj->marker) 2826 continue; 2827 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2828 return (-1); 2829 } 2830 return (0); 2831 } 2832 2833 static int 2834 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2835 RtldLockState *lockstate) 2836 { 2837 Objlist_Entry *elm; 2838 2839 STAILQ_FOREACH(elm, list, link) { 2840 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2841 lockstate) == -1) 2842 return (-1); 2843 } 2844 return (0); 2845 } 2846 2847 /* 2848 * Cleanup procedure. It will be called (by the atexit mechanism) just 2849 * before the process exits. 2850 */ 2851 static void 2852 rtld_exit(void) 2853 { 2854 RtldLockState lockstate; 2855 2856 wlock_acquire(rtld_bind_lock, &lockstate); 2857 dbg("rtld_exit()"); 2858 objlist_call_fini(&list_fini, NULL, &lockstate); 2859 /* No need to remove the items from the list, since we are exiting. */ 2860 if (!libmap_disable) 2861 lm_fini(); 2862 lock_release(rtld_bind_lock, &lockstate); 2863 } 2864 2865 /* 2866 * Iterate over a search path, translate each element, and invoke the 2867 * callback on the result. 2868 */ 2869 static void * 2870 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2871 { 2872 const char *trans; 2873 if (path == NULL) 2874 return (NULL); 2875 2876 path += strspn(path, ":;"); 2877 while (*path != '\0') { 2878 size_t len; 2879 char *res; 2880 2881 len = strcspn(path, ":;"); 2882 trans = lm_findn(NULL, path, len); 2883 if (trans) 2884 res = callback(trans, strlen(trans), arg); 2885 else 2886 res = callback(path, len, arg); 2887 2888 if (res != NULL) 2889 return (res); 2890 2891 path += len; 2892 path += strspn(path, ":;"); 2893 } 2894 2895 return (NULL); 2896 } 2897 2898 struct try_library_args { 2899 const char *name; 2900 size_t namelen; 2901 char *buffer; 2902 size_t buflen; 2903 }; 2904 2905 static void * 2906 try_library_path(const char *dir, size_t dirlen, void *param) 2907 { 2908 struct try_library_args *arg; 2909 2910 arg = param; 2911 if (*dir == '/' || trust) { 2912 char *pathname; 2913 2914 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2915 return (NULL); 2916 2917 pathname = arg->buffer; 2918 strncpy(pathname, dir, dirlen); 2919 pathname[dirlen] = '/'; 2920 strcpy(pathname + dirlen + 1, arg->name); 2921 2922 dbg(" Trying \"%s\"", pathname); 2923 if (access(pathname, F_OK) == 0) { /* We found it */ 2924 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2925 strcpy(pathname, arg->buffer); 2926 return (pathname); 2927 } 2928 } 2929 return (NULL); 2930 } 2931 2932 static char * 2933 search_library_path(const char *name, const char *path) 2934 { 2935 char *p; 2936 struct try_library_args arg; 2937 2938 if (path == NULL) 2939 return NULL; 2940 2941 arg.name = name; 2942 arg.namelen = strlen(name); 2943 arg.buffer = xmalloc(PATH_MAX); 2944 arg.buflen = PATH_MAX; 2945 2946 p = path_enumerate(path, try_library_path, &arg); 2947 2948 free(arg.buffer); 2949 2950 return (p); 2951 } 2952 2953 2954 /* 2955 * Finds the library with the given name using the directory descriptors 2956 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2957 * 2958 * Returns a freshly-opened close-on-exec file descriptor for the library, 2959 * or -1 if the library cannot be found. 2960 */ 2961 static char * 2962 search_library_pathfds(const char *name, const char *path, int *fdp) 2963 { 2964 char *envcopy, *fdstr, *found, *last_token; 2965 size_t len; 2966 int dirfd, fd; 2967 2968 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2969 2970 /* Don't load from user-specified libdirs into setuid binaries. */ 2971 if (!trust) 2972 return (NULL); 2973 2974 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2975 if (path == NULL) 2976 return (NULL); 2977 2978 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2979 if (name[0] == '/') { 2980 dbg("Absolute path (%s) passed to %s", name, __func__); 2981 return (NULL); 2982 } 2983 2984 /* 2985 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2986 * copy of the path, as strtok_r rewrites separator tokens 2987 * with '\0'. 2988 */ 2989 found = NULL; 2990 envcopy = xstrdup(path); 2991 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2992 fdstr = strtok_r(NULL, ":", &last_token)) { 2993 dirfd = parse_libdir(fdstr); 2994 if (dirfd < 0) 2995 break; 2996 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2997 if (fd >= 0) { 2998 *fdp = fd; 2999 len = strlen(fdstr) + strlen(name) + 3; 3000 found = xmalloc(len); 3001 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3002 _rtld_error("error generating '%d/%s'", 3003 dirfd, name); 3004 rtld_die(); 3005 } 3006 dbg("open('%s') => %d", found, fd); 3007 break; 3008 } 3009 } 3010 free(envcopy); 3011 3012 return (found); 3013 } 3014 3015 3016 int 3017 dlclose(void *handle) 3018 { 3019 RtldLockState lockstate; 3020 int error; 3021 3022 wlock_acquire(rtld_bind_lock, &lockstate); 3023 error = dlclose_locked(handle, &lockstate); 3024 lock_release(rtld_bind_lock, &lockstate); 3025 return (error); 3026 } 3027 3028 static int 3029 dlclose_locked(void *handle, RtldLockState *lockstate) 3030 { 3031 Obj_Entry *root; 3032 3033 root = dlcheck(handle); 3034 if (root == NULL) 3035 return -1; 3036 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3037 root->path); 3038 3039 /* Unreference the object and its dependencies. */ 3040 root->dl_refcount--; 3041 3042 if (root->refcount == 1) { 3043 /* 3044 * The object will be no longer referenced, so we must unload it. 3045 * First, call the fini functions. 3046 */ 3047 objlist_call_fini(&list_fini, root, lockstate); 3048 3049 unref_dag(root); 3050 3051 /* Finish cleaning up the newly-unreferenced objects. */ 3052 GDB_STATE(RT_DELETE,&root->linkmap); 3053 unload_object(root, lockstate); 3054 GDB_STATE(RT_CONSISTENT,NULL); 3055 } else 3056 unref_dag(root); 3057 3058 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3059 return 0; 3060 } 3061 3062 char * 3063 dlerror(void) 3064 { 3065 char *msg = error_message; 3066 error_message = NULL; 3067 return msg; 3068 } 3069 3070 /* 3071 * This function is deprecated and has no effect. 3072 */ 3073 void 3074 dllockinit(void *context, 3075 void *(*lock_create)(void *context), 3076 void (*rlock_acquire)(void *lock), 3077 void (*wlock_acquire)(void *lock), 3078 void (*lock_release)(void *lock), 3079 void (*lock_destroy)(void *lock), 3080 void (*context_destroy)(void *context)) 3081 { 3082 static void *cur_context; 3083 static void (*cur_context_destroy)(void *); 3084 3085 /* Just destroy the context from the previous call, if necessary. */ 3086 if (cur_context_destroy != NULL) 3087 cur_context_destroy(cur_context); 3088 cur_context = context; 3089 cur_context_destroy = context_destroy; 3090 } 3091 3092 void * 3093 dlopen(const char *name, int mode) 3094 { 3095 3096 return (rtld_dlopen(name, -1, mode)); 3097 } 3098 3099 void * 3100 fdlopen(int fd, int mode) 3101 { 3102 3103 return (rtld_dlopen(NULL, fd, mode)); 3104 } 3105 3106 static void * 3107 rtld_dlopen(const char *name, int fd, int mode) 3108 { 3109 RtldLockState lockstate; 3110 int lo_flags; 3111 3112 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3113 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3114 if (ld_tracing != NULL) { 3115 rlock_acquire(rtld_bind_lock, &lockstate); 3116 if (sigsetjmp(lockstate.env, 0) != 0) 3117 lock_upgrade(rtld_bind_lock, &lockstate); 3118 environ = (char **)*get_program_var_addr("environ", &lockstate); 3119 lock_release(rtld_bind_lock, &lockstate); 3120 } 3121 lo_flags = RTLD_LO_DLOPEN; 3122 if (mode & RTLD_NODELETE) 3123 lo_flags |= RTLD_LO_NODELETE; 3124 if (mode & RTLD_NOLOAD) 3125 lo_flags |= RTLD_LO_NOLOAD; 3126 if (ld_tracing != NULL) 3127 lo_flags |= RTLD_LO_TRACE; 3128 3129 return (dlopen_object(name, fd, obj_main, lo_flags, 3130 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3131 } 3132 3133 static void 3134 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3135 { 3136 3137 obj->dl_refcount--; 3138 unref_dag(obj); 3139 if (obj->refcount == 0) 3140 unload_object(obj, lockstate); 3141 } 3142 3143 static Obj_Entry * 3144 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3145 int mode, RtldLockState *lockstate) 3146 { 3147 Obj_Entry *old_obj_tail; 3148 Obj_Entry *obj; 3149 Objlist initlist; 3150 RtldLockState mlockstate; 3151 int result; 3152 3153 objlist_init(&initlist); 3154 3155 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3156 wlock_acquire(rtld_bind_lock, &mlockstate); 3157 lockstate = &mlockstate; 3158 } 3159 GDB_STATE(RT_ADD,NULL); 3160 3161 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3162 obj = NULL; 3163 if (name == NULL && fd == -1) { 3164 obj = obj_main; 3165 obj->refcount++; 3166 } else { 3167 obj = load_object(name, fd, refobj, lo_flags); 3168 } 3169 3170 if (obj) { 3171 obj->dl_refcount++; 3172 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3173 objlist_push_tail(&list_global, obj); 3174 if (globallist_next(old_obj_tail) != NULL) { 3175 /* We loaded something new. */ 3176 assert(globallist_next(old_obj_tail) == obj); 3177 result = load_needed_objects(obj, 3178 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3179 init_dag(obj); 3180 ref_dag(obj); 3181 if (result != -1) 3182 result = rtld_verify_versions(&obj->dagmembers); 3183 if (result != -1 && ld_tracing) 3184 goto trace; 3185 if (result == -1 || relocate_object_dag(obj, 3186 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3187 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3188 lockstate) == -1) { 3189 dlopen_cleanup(obj, lockstate); 3190 obj = NULL; 3191 } else if (lo_flags & RTLD_LO_EARLY) { 3192 /* 3193 * Do not call the init functions for early loaded 3194 * filtees. The image is still not initialized enough 3195 * for them to work. 3196 * 3197 * Our object is found by the global object list and 3198 * will be ordered among all init calls done right 3199 * before transferring control to main. 3200 */ 3201 } else { 3202 /* Make list of init functions to call. */ 3203 initlist_add_objects(obj, obj, &initlist); 3204 } 3205 /* 3206 * Process all no_delete or global objects here, given 3207 * them own DAGs to prevent their dependencies from being 3208 * unloaded. This has to be done after we have loaded all 3209 * of the dependencies, so that we do not miss any. 3210 */ 3211 if (obj != NULL) 3212 process_z(obj); 3213 } else { 3214 /* 3215 * Bump the reference counts for objects on this DAG. If 3216 * this is the first dlopen() call for the object that was 3217 * already loaded as a dependency, initialize the dag 3218 * starting at it. 3219 */ 3220 init_dag(obj); 3221 ref_dag(obj); 3222 3223 if ((lo_flags & RTLD_LO_TRACE) != 0) 3224 goto trace; 3225 } 3226 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3227 obj->z_nodelete) && !obj->ref_nodel) { 3228 dbg("obj %s nodelete", obj->path); 3229 ref_dag(obj); 3230 obj->z_nodelete = obj->ref_nodel = true; 3231 } 3232 } 3233 3234 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3235 name); 3236 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3237 3238 if (!(lo_flags & RTLD_LO_EARLY)) { 3239 map_stacks_exec(lockstate); 3240 } 3241 3242 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3243 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3244 lockstate) == -1) { 3245 objlist_clear(&initlist); 3246 dlopen_cleanup(obj, lockstate); 3247 if (lockstate == &mlockstate) 3248 lock_release(rtld_bind_lock, lockstate); 3249 return (NULL); 3250 } 3251 3252 if (!(lo_flags & RTLD_LO_EARLY)) { 3253 /* Call the init functions. */ 3254 objlist_call_init(&initlist, lockstate); 3255 } 3256 objlist_clear(&initlist); 3257 if (lockstate == &mlockstate) 3258 lock_release(rtld_bind_lock, lockstate); 3259 return obj; 3260 trace: 3261 trace_loaded_objects(obj); 3262 if (lockstate == &mlockstate) 3263 lock_release(rtld_bind_lock, lockstate); 3264 exit(0); 3265 } 3266 3267 static void * 3268 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3269 int flags) 3270 { 3271 DoneList donelist; 3272 const Obj_Entry *obj, *defobj; 3273 const Elf_Sym *def; 3274 SymLook req; 3275 RtldLockState lockstate; 3276 tls_index ti; 3277 void *sym; 3278 int res; 3279 3280 def = NULL; 3281 defobj = NULL; 3282 symlook_init(&req, name); 3283 req.ventry = ve; 3284 req.flags = flags | SYMLOOK_IN_PLT; 3285 req.lockstate = &lockstate; 3286 3287 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3288 rlock_acquire(rtld_bind_lock, &lockstate); 3289 if (sigsetjmp(lockstate.env, 0) != 0) 3290 lock_upgrade(rtld_bind_lock, &lockstate); 3291 if (handle == NULL || handle == RTLD_NEXT || 3292 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3293 3294 if ((obj = obj_from_addr(retaddr)) == NULL) { 3295 _rtld_error("Cannot determine caller's shared object"); 3296 lock_release(rtld_bind_lock, &lockstate); 3297 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3298 return NULL; 3299 } 3300 if (handle == NULL) { /* Just the caller's shared object. */ 3301 res = symlook_obj(&req, obj); 3302 if (res == 0) { 3303 def = req.sym_out; 3304 defobj = req.defobj_out; 3305 } 3306 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3307 handle == RTLD_SELF) { /* ... caller included */ 3308 if (handle == RTLD_NEXT) 3309 obj = globallist_next(obj); 3310 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3311 if (obj->marker) 3312 continue; 3313 res = symlook_obj(&req, obj); 3314 if (res == 0) { 3315 if (def == NULL || 3316 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3317 def = req.sym_out; 3318 defobj = req.defobj_out; 3319 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3320 break; 3321 } 3322 } 3323 } 3324 /* 3325 * Search the dynamic linker itself, and possibly resolve the 3326 * symbol from there. This is how the application links to 3327 * dynamic linker services such as dlopen. 3328 */ 3329 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3330 res = symlook_obj(&req, &obj_rtld); 3331 if (res == 0) { 3332 def = req.sym_out; 3333 defobj = req.defobj_out; 3334 } 3335 } 3336 } else { 3337 assert(handle == RTLD_DEFAULT); 3338 res = symlook_default(&req, obj); 3339 if (res == 0) { 3340 defobj = req.defobj_out; 3341 def = req.sym_out; 3342 } 3343 } 3344 } else { 3345 if ((obj = dlcheck(handle)) == NULL) { 3346 lock_release(rtld_bind_lock, &lockstate); 3347 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3348 return NULL; 3349 } 3350 3351 donelist_init(&donelist); 3352 if (obj->mainprog) { 3353 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3354 res = symlook_global(&req, &donelist); 3355 if (res == 0) { 3356 def = req.sym_out; 3357 defobj = req.defobj_out; 3358 } 3359 /* 3360 * Search the dynamic linker itself, and possibly resolve the 3361 * symbol from there. This is how the application links to 3362 * dynamic linker services such as dlopen. 3363 */ 3364 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3365 res = symlook_obj(&req, &obj_rtld); 3366 if (res == 0) { 3367 def = req.sym_out; 3368 defobj = req.defobj_out; 3369 } 3370 } 3371 } 3372 else { 3373 /* Search the whole DAG rooted at the given object. */ 3374 res = symlook_list(&req, &obj->dagmembers, &donelist); 3375 if (res == 0) { 3376 def = req.sym_out; 3377 defobj = req.defobj_out; 3378 } 3379 } 3380 } 3381 3382 if (def != NULL) { 3383 lock_release(rtld_bind_lock, &lockstate); 3384 3385 /* 3386 * The value required by the caller is derived from the value 3387 * of the symbol. this is simply the relocated value of the 3388 * symbol. 3389 */ 3390 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3391 sym = make_function_pointer(def, defobj); 3392 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3393 sym = rtld_resolve_ifunc(defobj, def); 3394 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3395 ti.ti_module = defobj->tlsindex; 3396 ti.ti_offset = def->st_value; 3397 sym = __tls_get_addr(&ti); 3398 } else 3399 sym = defobj->relocbase + def->st_value; 3400 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3401 return (sym); 3402 } 3403 3404 _rtld_error("Undefined symbol \"%s\"", name); 3405 lock_release(rtld_bind_lock, &lockstate); 3406 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3407 return NULL; 3408 } 3409 3410 void * 3411 dlsym(void *handle, const char *name) 3412 { 3413 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3414 SYMLOOK_DLSYM); 3415 } 3416 3417 dlfunc_t 3418 dlfunc(void *handle, const char *name) 3419 { 3420 union { 3421 void *d; 3422 dlfunc_t f; 3423 } rv; 3424 3425 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3426 SYMLOOK_DLSYM); 3427 return (rv.f); 3428 } 3429 3430 void * 3431 dlvsym(void *handle, const char *name, const char *version) 3432 { 3433 Ver_Entry ventry; 3434 3435 ventry.name = version; 3436 ventry.file = NULL; 3437 ventry.hash = elf_hash(version); 3438 ventry.flags= 0; 3439 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3440 SYMLOOK_DLSYM); 3441 } 3442 3443 int 3444 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3445 { 3446 const Obj_Entry *obj; 3447 RtldLockState lockstate; 3448 3449 rlock_acquire(rtld_bind_lock, &lockstate); 3450 obj = obj_from_addr(addr); 3451 if (obj == NULL) { 3452 _rtld_error("No shared object contains address"); 3453 lock_release(rtld_bind_lock, &lockstate); 3454 return (0); 3455 } 3456 rtld_fill_dl_phdr_info(obj, phdr_info); 3457 lock_release(rtld_bind_lock, &lockstate); 3458 return (1); 3459 } 3460 3461 int 3462 dladdr(const void *addr, Dl_info *info) 3463 { 3464 const Obj_Entry *obj; 3465 const Elf_Sym *def; 3466 void *symbol_addr; 3467 unsigned long symoffset; 3468 RtldLockState lockstate; 3469 3470 rlock_acquire(rtld_bind_lock, &lockstate); 3471 obj = obj_from_addr(addr); 3472 if (obj == NULL) { 3473 _rtld_error("No shared object contains address"); 3474 lock_release(rtld_bind_lock, &lockstate); 3475 return 0; 3476 } 3477 info->dli_fname = obj->path; 3478 info->dli_fbase = obj->mapbase; 3479 info->dli_saddr = (void *)0; 3480 info->dli_sname = NULL; 3481 3482 /* 3483 * Walk the symbol list looking for the symbol whose address is 3484 * closest to the address sent in. 3485 */ 3486 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3487 def = obj->symtab + symoffset; 3488 3489 /* 3490 * For skip the symbol if st_shndx is either SHN_UNDEF or 3491 * SHN_COMMON. 3492 */ 3493 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3494 continue; 3495 3496 /* 3497 * If the symbol is greater than the specified address, or if it 3498 * is further away from addr than the current nearest symbol, 3499 * then reject it. 3500 */ 3501 symbol_addr = obj->relocbase + def->st_value; 3502 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3503 continue; 3504 3505 /* Update our idea of the nearest symbol. */ 3506 info->dli_sname = obj->strtab + def->st_name; 3507 info->dli_saddr = symbol_addr; 3508 3509 /* Exact match? */ 3510 if (info->dli_saddr == addr) 3511 break; 3512 } 3513 lock_release(rtld_bind_lock, &lockstate); 3514 return 1; 3515 } 3516 3517 int 3518 dlinfo(void *handle, int request, void *p) 3519 { 3520 const Obj_Entry *obj; 3521 RtldLockState lockstate; 3522 int error; 3523 3524 rlock_acquire(rtld_bind_lock, &lockstate); 3525 3526 if (handle == NULL || handle == RTLD_SELF) { 3527 void *retaddr; 3528 3529 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3530 if ((obj = obj_from_addr(retaddr)) == NULL) 3531 _rtld_error("Cannot determine caller's shared object"); 3532 } else 3533 obj = dlcheck(handle); 3534 3535 if (obj == NULL) { 3536 lock_release(rtld_bind_lock, &lockstate); 3537 return (-1); 3538 } 3539 3540 error = 0; 3541 switch (request) { 3542 case RTLD_DI_LINKMAP: 3543 *((struct link_map const **)p) = &obj->linkmap; 3544 break; 3545 case RTLD_DI_ORIGIN: 3546 error = rtld_dirname(obj->path, p); 3547 break; 3548 3549 case RTLD_DI_SERINFOSIZE: 3550 case RTLD_DI_SERINFO: 3551 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3552 break; 3553 3554 default: 3555 _rtld_error("Invalid request %d passed to dlinfo()", request); 3556 error = -1; 3557 } 3558 3559 lock_release(rtld_bind_lock, &lockstate); 3560 3561 return (error); 3562 } 3563 3564 static void 3565 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3566 { 3567 3568 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3569 phdr_info->dlpi_name = obj->path; 3570 phdr_info->dlpi_phdr = obj->phdr; 3571 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3572 phdr_info->dlpi_tls_modid = obj->tlsindex; 3573 phdr_info->dlpi_tls_data = obj->tlsinit; 3574 phdr_info->dlpi_adds = obj_loads; 3575 phdr_info->dlpi_subs = obj_loads - obj_count; 3576 } 3577 3578 int 3579 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3580 { 3581 struct dl_phdr_info phdr_info; 3582 Obj_Entry *obj, marker; 3583 RtldLockState bind_lockstate, phdr_lockstate; 3584 int error; 3585 3586 init_marker(&marker); 3587 error = 0; 3588 3589 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3590 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3591 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3592 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3593 rtld_fill_dl_phdr_info(obj, &phdr_info); 3594 hold_object(obj); 3595 lock_release(rtld_bind_lock, &bind_lockstate); 3596 3597 error = callback(&phdr_info, sizeof phdr_info, param); 3598 3599 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3600 unhold_object(obj); 3601 obj = globallist_next(&marker); 3602 TAILQ_REMOVE(&obj_list, &marker, next); 3603 if (error != 0) { 3604 lock_release(rtld_bind_lock, &bind_lockstate); 3605 lock_release(rtld_phdr_lock, &phdr_lockstate); 3606 return (error); 3607 } 3608 } 3609 3610 if (error == 0) { 3611 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3612 lock_release(rtld_bind_lock, &bind_lockstate); 3613 error = callback(&phdr_info, sizeof(phdr_info), param); 3614 } 3615 lock_release(rtld_phdr_lock, &phdr_lockstate); 3616 return (error); 3617 } 3618 3619 static void * 3620 fill_search_info(const char *dir, size_t dirlen, void *param) 3621 { 3622 struct fill_search_info_args *arg; 3623 3624 arg = param; 3625 3626 if (arg->request == RTLD_DI_SERINFOSIZE) { 3627 arg->serinfo->dls_cnt ++; 3628 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3629 } else { 3630 struct dl_serpath *s_entry; 3631 3632 s_entry = arg->serpath; 3633 s_entry->dls_name = arg->strspace; 3634 s_entry->dls_flags = arg->flags; 3635 3636 strncpy(arg->strspace, dir, dirlen); 3637 arg->strspace[dirlen] = '\0'; 3638 3639 arg->strspace += dirlen + 1; 3640 arg->serpath++; 3641 } 3642 3643 return (NULL); 3644 } 3645 3646 static int 3647 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3648 { 3649 struct dl_serinfo _info; 3650 struct fill_search_info_args args; 3651 3652 args.request = RTLD_DI_SERINFOSIZE; 3653 args.serinfo = &_info; 3654 3655 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3656 _info.dls_cnt = 0; 3657 3658 path_enumerate(obj->rpath, fill_search_info, &args); 3659 path_enumerate(ld_library_path, fill_search_info, &args); 3660 path_enumerate(obj->runpath, fill_search_info, &args); 3661 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3662 if (!obj->z_nodeflib) 3663 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3664 3665 3666 if (request == RTLD_DI_SERINFOSIZE) { 3667 info->dls_size = _info.dls_size; 3668 info->dls_cnt = _info.dls_cnt; 3669 return (0); 3670 } 3671 3672 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3673 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3674 return (-1); 3675 } 3676 3677 args.request = RTLD_DI_SERINFO; 3678 args.serinfo = info; 3679 args.serpath = &info->dls_serpath[0]; 3680 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3681 3682 args.flags = LA_SER_RUNPATH; 3683 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3684 return (-1); 3685 3686 args.flags = LA_SER_LIBPATH; 3687 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3688 return (-1); 3689 3690 args.flags = LA_SER_RUNPATH; 3691 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3692 return (-1); 3693 3694 args.flags = LA_SER_CONFIG; 3695 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3696 != NULL) 3697 return (-1); 3698 3699 args.flags = LA_SER_DEFAULT; 3700 if (!obj->z_nodeflib && 3701 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3702 return (-1); 3703 return (0); 3704 } 3705 3706 static int 3707 rtld_dirname(const char *path, char *bname) 3708 { 3709 const char *endp; 3710 3711 /* Empty or NULL string gets treated as "." */ 3712 if (path == NULL || *path == '\0') { 3713 bname[0] = '.'; 3714 bname[1] = '\0'; 3715 return (0); 3716 } 3717 3718 /* Strip trailing slashes */ 3719 endp = path + strlen(path) - 1; 3720 while (endp > path && *endp == '/') 3721 endp--; 3722 3723 /* Find the start of the dir */ 3724 while (endp > path && *endp != '/') 3725 endp--; 3726 3727 /* Either the dir is "/" or there are no slashes */ 3728 if (endp == path) { 3729 bname[0] = *endp == '/' ? '/' : '.'; 3730 bname[1] = '\0'; 3731 return (0); 3732 } else { 3733 do { 3734 endp--; 3735 } while (endp > path && *endp == '/'); 3736 } 3737 3738 if (endp - path + 2 > PATH_MAX) 3739 { 3740 _rtld_error("Filename is too long: %s", path); 3741 return(-1); 3742 } 3743 3744 strncpy(bname, path, endp - path + 1); 3745 bname[endp - path + 1] = '\0'; 3746 return (0); 3747 } 3748 3749 static int 3750 rtld_dirname_abs(const char *path, char *base) 3751 { 3752 char *last; 3753 3754 if (realpath(path, base) == NULL) 3755 return (-1); 3756 dbg("%s -> %s", path, base); 3757 last = strrchr(base, '/'); 3758 if (last == NULL) 3759 return (-1); 3760 if (last != base) 3761 *last = '\0'; 3762 return (0); 3763 } 3764 3765 static void 3766 linkmap_add(Obj_Entry *obj) 3767 { 3768 struct link_map *l = &obj->linkmap; 3769 struct link_map *prev; 3770 3771 obj->linkmap.l_name = obj->path; 3772 obj->linkmap.l_addr = obj->mapbase; 3773 obj->linkmap.l_ld = obj->dynamic; 3774 #ifdef __mips__ 3775 /* GDB needs load offset on MIPS to use the symbols */ 3776 obj->linkmap.l_offs = obj->relocbase; 3777 #endif 3778 3779 if (r_debug.r_map == NULL) { 3780 r_debug.r_map = l; 3781 return; 3782 } 3783 3784 /* 3785 * Scan to the end of the list, but not past the entry for the 3786 * dynamic linker, which we want to keep at the very end. 3787 */ 3788 for (prev = r_debug.r_map; 3789 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3790 prev = prev->l_next) 3791 ; 3792 3793 /* Link in the new entry. */ 3794 l->l_prev = prev; 3795 l->l_next = prev->l_next; 3796 if (l->l_next != NULL) 3797 l->l_next->l_prev = l; 3798 prev->l_next = l; 3799 } 3800 3801 static void 3802 linkmap_delete(Obj_Entry *obj) 3803 { 3804 struct link_map *l = &obj->linkmap; 3805 3806 if (l->l_prev == NULL) { 3807 if ((r_debug.r_map = l->l_next) != NULL) 3808 l->l_next->l_prev = NULL; 3809 return; 3810 } 3811 3812 if ((l->l_prev->l_next = l->l_next) != NULL) 3813 l->l_next->l_prev = l->l_prev; 3814 } 3815 3816 /* 3817 * Function for the debugger to set a breakpoint on to gain control. 3818 * 3819 * The two parameters allow the debugger to easily find and determine 3820 * what the runtime loader is doing and to whom it is doing it. 3821 * 3822 * When the loadhook trap is hit (r_debug_state, set at program 3823 * initialization), the arguments can be found on the stack: 3824 * 3825 * +8 struct link_map *m 3826 * +4 struct r_debug *rd 3827 * +0 RetAddr 3828 */ 3829 void 3830 r_debug_state(struct r_debug* rd, struct link_map *m) 3831 { 3832 /* 3833 * The following is a hack to force the compiler to emit calls to 3834 * this function, even when optimizing. If the function is empty, 3835 * the compiler is not obliged to emit any code for calls to it, 3836 * even when marked __noinline. However, gdb depends on those 3837 * calls being made. 3838 */ 3839 __compiler_membar(); 3840 } 3841 3842 /* 3843 * A function called after init routines have completed. This can be used to 3844 * break before a program's entry routine is called, and can be used when 3845 * main is not available in the symbol table. 3846 */ 3847 void 3848 _r_debug_postinit(struct link_map *m) 3849 { 3850 3851 /* See r_debug_state(). */ 3852 __compiler_membar(); 3853 } 3854 3855 static void 3856 release_object(Obj_Entry *obj) 3857 { 3858 3859 if (obj->holdcount > 0) { 3860 obj->unholdfree = true; 3861 return; 3862 } 3863 munmap(obj->mapbase, obj->mapsize); 3864 linkmap_delete(obj); 3865 obj_free(obj); 3866 } 3867 3868 /* 3869 * Get address of the pointer variable in the main program. 3870 * Prefer non-weak symbol over the weak one. 3871 */ 3872 static const void ** 3873 get_program_var_addr(const char *name, RtldLockState *lockstate) 3874 { 3875 SymLook req; 3876 DoneList donelist; 3877 3878 symlook_init(&req, name); 3879 req.lockstate = lockstate; 3880 donelist_init(&donelist); 3881 if (symlook_global(&req, &donelist) != 0) 3882 return (NULL); 3883 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3884 return ((const void **)make_function_pointer(req.sym_out, 3885 req.defobj_out)); 3886 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3887 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3888 else 3889 return ((const void **)(req.defobj_out->relocbase + 3890 req.sym_out->st_value)); 3891 } 3892 3893 /* 3894 * Set a pointer variable in the main program to the given value. This 3895 * is used to set key variables such as "environ" before any of the 3896 * init functions are called. 3897 */ 3898 static void 3899 set_program_var(const char *name, const void *value) 3900 { 3901 const void **addr; 3902 3903 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3904 dbg("\"%s\": *%p <-- %p", name, addr, value); 3905 *addr = value; 3906 } 3907 } 3908 3909 /* 3910 * Search the global objects, including dependencies and main object, 3911 * for the given symbol. 3912 */ 3913 static int 3914 symlook_global(SymLook *req, DoneList *donelist) 3915 { 3916 SymLook req1; 3917 const Objlist_Entry *elm; 3918 int res; 3919 3920 symlook_init_from_req(&req1, req); 3921 3922 /* Search all objects loaded at program start up. */ 3923 if (req->defobj_out == NULL || 3924 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3925 res = symlook_list(&req1, &list_main, donelist); 3926 if (res == 0 && (req->defobj_out == NULL || 3927 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3928 req->sym_out = req1.sym_out; 3929 req->defobj_out = req1.defobj_out; 3930 assert(req->defobj_out != NULL); 3931 } 3932 } 3933 3934 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3935 STAILQ_FOREACH(elm, &list_global, link) { 3936 if (req->defobj_out != NULL && 3937 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3938 break; 3939 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3940 if (res == 0 && (req->defobj_out == NULL || 3941 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3942 req->sym_out = req1.sym_out; 3943 req->defobj_out = req1.defobj_out; 3944 assert(req->defobj_out != NULL); 3945 } 3946 } 3947 3948 return (req->sym_out != NULL ? 0 : ESRCH); 3949 } 3950 3951 /* 3952 * Given a symbol name in a referencing object, find the corresponding 3953 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3954 * no definition was found. Returns a pointer to the Obj_Entry of the 3955 * defining object via the reference parameter DEFOBJ_OUT. 3956 */ 3957 static int 3958 symlook_default(SymLook *req, const Obj_Entry *refobj) 3959 { 3960 DoneList donelist; 3961 const Objlist_Entry *elm; 3962 SymLook req1; 3963 int res; 3964 3965 donelist_init(&donelist); 3966 symlook_init_from_req(&req1, req); 3967 3968 /* 3969 * Look first in the referencing object if linked symbolically, 3970 * and similarly handle protected symbols. 3971 */ 3972 res = symlook_obj(&req1, refobj); 3973 if (res == 0 && (refobj->symbolic || 3974 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 3975 req->sym_out = req1.sym_out; 3976 req->defobj_out = req1.defobj_out; 3977 assert(req->defobj_out != NULL); 3978 } 3979 if (refobj->symbolic || req->defobj_out != NULL) 3980 donelist_check(&donelist, refobj); 3981 3982 symlook_global(req, &donelist); 3983 3984 /* Search all dlopened DAGs containing the referencing object. */ 3985 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3986 if (req->sym_out != NULL && 3987 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3988 break; 3989 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3990 if (res == 0 && (req->sym_out == NULL || 3991 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3992 req->sym_out = req1.sym_out; 3993 req->defobj_out = req1.defobj_out; 3994 assert(req->defobj_out != NULL); 3995 } 3996 } 3997 3998 /* 3999 * Search the dynamic linker itself, and possibly resolve the 4000 * symbol from there. This is how the application links to 4001 * dynamic linker services such as dlopen. 4002 */ 4003 if (req->sym_out == NULL || 4004 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4005 res = symlook_obj(&req1, &obj_rtld); 4006 if (res == 0) { 4007 req->sym_out = req1.sym_out; 4008 req->defobj_out = req1.defobj_out; 4009 assert(req->defobj_out != NULL); 4010 } 4011 } 4012 4013 return (req->sym_out != NULL ? 0 : ESRCH); 4014 } 4015 4016 static int 4017 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4018 { 4019 const Elf_Sym *def; 4020 const Obj_Entry *defobj; 4021 const Objlist_Entry *elm; 4022 SymLook req1; 4023 int res; 4024 4025 def = NULL; 4026 defobj = NULL; 4027 STAILQ_FOREACH(elm, objlist, link) { 4028 if (donelist_check(dlp, elm->obj)) 4029 continue; 4030 symlook_init_from_req(&req1, req); 4031 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4032 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4033 def = req1.sym_out; 4034 defobj = req1.defobj_out; 4035 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4036 break; 4037 } 4038 } 4039 } 4040 if (def != NULL) { 4041 req->sym_out = def; 4042 req->defobj_out = defobj; 4043 return (0); 4044 } 4045 return (ESRCH); 4046 } 4047 4048 /* 4049 * Search the chain of DAGS cointed to by the given Needed_Entry 4050 * for a symbol of the given name. Each DAG is scanned completely 4051 * before advancing to the next one. Returns a pointer to the symbol, 4052 * or NULL if no definition was found. 4053 */ 4054 static int 4055 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4056 { 4057 const Elf_Sym *def; 4058 const Needed_Entry *n; 4059 const Obj_Entry *defobj; 4060 SymLook req1; 4061 int res; 4062 4063 def = NULL; 4064 defobj = NULL; 4065 symlook_init_from_req(&req1, req); 4066 for (n = needed; n != NULL; n = n->next) { 4067 if (n->obj == NULL || 4068 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4069 continue; 4070 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4071 def = req1.sym_out; 4072 defobj = req1.defobj_out; 4073 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4074 break; 4075 } 4076 } 4077 if (def != NULL) { 4078 req->sym_out = def; 4079 req->defobj_out = defobj; 4080 return (0); 4081 } 4082 return (ESRCH); 4083 } 4084 4085 /* 4086 * Search the symbol table of a single shared object for a symbol of 4087 * the given name and version, if requested. Returns a pointer to the 4088 * symbol, or NULL if no definition was found. If the object is 4089 * filter, return filtered symbol from filtee. 4090 * 4091 * The symbol's hash value is passed in for efficiency reasons; that 4092 * eliminates many recomputations of the hash value. 4093 */ 4094 int 4095 symlook_obj(SymLook *req, const Obj_Entry *obj) 4096 { 4097 DoneList donelist; 4098 SymLook req1; 4099 int flags, res, mres; 4100 4101 /* 4102 * If there is at least one valid hash at this point, we prefer to 4103 * use the faster GNU version if available. 4104 */ 4105 if (obj->valid_hash_gnu) 4106 mres = symlook_obj1_gnu(req, obj); 4107 else if (obj->valid_hash_sysv) 4108 mres = symlook_obj1_sysv(req, obj); 4109 else 4110 return (EINVAL); 4111 4112 if (mres == 0) { 4113 if (obj->needed_filtees != NULL) { 4114 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4115 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4116 donelist_init(&donelist); 4117 symlook_init_from_req(&req1, req); 4118 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4119 if (res == 0) { 4120 req->sym_out = req1.sym_out; 4121 req->defobj_out = req1.defobj_out; 4122 } 4123 return (res); 4124 } 4125 if (obj->needed_aux_filtees != NULL) { 4126 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4127 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4128 donelist_init(&donelist); 4129 symlook_init_from_req(&req1, req); 4130 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4131 if (res == 0) { 4132 req->sym_out = req1.sym_out; 4133 req->defobj_out = req1.defobj_out; 4134 return (res); 4135 } 4136 } 4137 } 4138 return (mres); 4139 } 4140 4141 /* Symbol match routine common to both hash functions */ 4142 static bool 4143 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4144 const unsigned long symnum) 4145 { 4146 Elf_Versym verndx; 4147 const Elf_Sym *symp; 4148 const char *strp; 4149 4150 symp = obj->symtab + symnum; 4151 strp = obj->strtab + symp->st_name; 4152 4153 switch (ELF_ST_TYPE(symp->st_info)) { 4154 case STT_FUNC: 4155 case STT_NOTYPE: 4156 case STT_OBJECT: 4157 case STT_COMMON: 4158 case STT_GNU_IFUNC: 4159 if (symp->st_value == 0) 4160 return (false); 4161 /* fallthrough */ 4162 case STT_TLS: 4163 if (symp->st_shndx != SHN_UNDEF) 4164 break; 4165 #ifndef __mips__ 4166 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4167 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4168 break; 4169 /* fallthrough */ 4170 #endif 4171 default: 4172 return (false); 4173 } 4174 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4175 return (false); 4176 4177 if (req->ventry == NULL) { 4178 if (obj->versyms != NULL) { 4179 verndx = VER_NDX(obj->versyms[symnum]); 4180 if (verndx > obj->vernum) { 4181 _rtld_error( 4182 "%s: symbol %s references wrong version %d", 4183 obj->path, obj->strtab + symnum, verndx); 4184 return (false); 4185 } 4186 /* 4187 * If we are not called from dlsym (i.e. this 4188 * is a normal relocation from unversioned 4189 * binary), accept the symbol immediately if 4190 * it happens to have first version after this 4191 * shared object became versioned. Otherwise, 4192 * if symbol is versioned and not hidden, 4193 * remember it. If it is the only symbol with 4194 * this name exported by the shared object, it 4195 * will be returned as a match by the calling 4196 * function. If symbol is global (verndx < 2) 4197 * accept it unconditionally. 4198 */ 4199 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4200 verndx == VER_NDX_GIVEN) { 4201 result->sym_out = symp; 4202 return (true); 4203 } 4204 else if (verndx >= VER_NDX_GIVEN) { 4205 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4206 == 0) { 4207 if (result->vsymp == NULL) 4208 result->vsymp = symp; 4209 result->vcount++; 4210 } 4211 return (false); 4212 } 4213 } 4214 result->sym_out = symp; 4215 return (true); 4216 } 4217 if (obj->versyms == NULL) { 4218 if (object_match_name(obj, req->ventry->name)) { 4219 _rtld_error("%s: object %s should provide version %s " 4220 "for symbol %s", obj_rtld.path, obj->path, 4221 req->ventry->name, obj->strtab + symnum); 4222 return (false); 4223 } 4224 } else { 4225 verndx = VER_NDX(obj->versyms[symnum]); 4226 if (verndx > obj->vernum) { 4227 _rtld_error("%s: symbol %s references wrong version %d", 4228 obj->path, obj->strtab + symnum, verndx); 4229 return (false); 4230 } 4231 if (obj->vertab[verndx].hash != req->ventry->hash || 4232 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4233 /* 4234 * Version does not match. Look if this is a 4235 * global symbol and if it is not hidden. If 4236 * global symbol (verndx < 2) is available, 4237 * use it. Do not return symbol if we are 4238 * called by dlvsym, because dlvsym looks for 4239 * a specific version and default one is not 4240 * what dlvsym wants. 4241 */ 4242 if ((req->flags & SYMLOOK_DLSYM) || 4243 (verndx >= VER_NDX_GIVEN) || 4244 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4245 return (false); 4246 } 4247 } 4248 result->sym_out = symp; 4249 return (true); 4250 } 4251 4252 /* 4253 * Search for symbol using SysV hash function. 4254 * obj->buckets is known not to be NULL at this point; the test for this was 4255 * performed with the obj->valid_hash_sysv assignment. 4256 */ 4257 static int 4258 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4259 { 4260 unsigned long symnum; 4261 Sym_Match_Result matchres; 4262 4263 matchres.sym_out = NULL; 4264 matchres.vsymp = NULL; 4265 matchres.vcount = 0; 4266 4267 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4268 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4269 if (symnum >= obj->nchains) 4270 return (ESRCH); /* Bad object */ 4271 4272 if (matched_symbol(req, obj, &matchres, symnum)) { 4273 req->sym_out = matchres.sym_out; 4274 req->defobj_out = obj; 4275 return (0); 4276 } 4277 } 4278 if (matchres.vcount == 1) { 4279 req->sym_out = matchres.vsymp; 4280 req->defobj_out = obj; 4281 return (0); 4282 } 4283 return (ESRCH); 4284 } 4285 4286 /* Search for symbol using GNU hash function */ 4287 static int 4288 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4289 { 4290 Elf_Addr bloom_word; 4291 const Elf32_Word *hashval; 4292 Elf32_Word bucket; 4293 Sym_Match_Result matchres; 4294 unsigned int h1, h2; 4295 unsigned long symnum; 4296 4297 matchres.sym_out = NULL; 4298 matchres.vsymp = NULL; 4299 matchres.vcount = 0; 4300 4301 /* Pick right bitmask word from Bloom filter array */ 4302 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4303 obj->maskwords_bm_gnu]; 4304 4305 /* Calculate modulus word size of gnu hash and its derivative */ 4306 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4307 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4308 4309 /* Filter out the "definitely not in set" queries */ 4310 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4311 return (ESRCH); 4312 4313 /* Locate hash chain and corresponding value element*/ 4314 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4315 if (bucket == 0) 4316 return (ESRCH); 4317 hashval = &obj->chain_zero_gnu[bucket]; 4318 do { 4319 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4320 symnum = hashval - obj->chain_zero_gnu; 4321 if (matched_symbol(req, obj, &matchres, symnum)) { 4322 req->sym_out = matchres.sym_out; 4323 req->defobj_out = obj; 4324 return (0); 4325 } 4326 } 4327 } while ((*hashval++ & 1) == 0); 4328 if (matchres.vcount == 1) { 4329 req->sym_out = matchres.vsymp; 4330 req->defobj_out = obj; 4331 return (0); 4332 } 4333 return (ESRCH); 4334 } 4335 4336 static void 4337 trace_loaded_objects(Obj_Entry *obj) 4338 { 4339 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4340 int c; 4341 4342 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4343 main_local = ""; 4344 4345 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4346 fmt1 = "\t%o => %p (%x)\n"; 4347 4348 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4349 fmt2 = "\t%o (%x)\n"; 4350 4351 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4352 4353 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4354 Needed_Entry *needed; 4355 char *name, *path; 4356 bool is_lib; 4357 4358 if (obj->marker) 4359 continue; 4360 if (list_containers && obj->needed != NULL) 4361 rtld_printf("%s:\n", obj->path); 4362 for (needed = obj->needed; needed; needed = needed->next) { 4363 if (needed->obj != NULL) { 4364 if (needed->obj->traced && !list_containers) 4365 continue; 4366 needed->obj->traced = true; 4367 path = needed->obj->path; 4368 } else 4369 path = "not found"; 4370 4371 name = (char *)obj->strtab + needed->name; 4372 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4373 4374 fmt = is_lib ? fmt1 : fmt2; 4375 while ((c = *fmt++) != '\0') { 4376 switch (c) { 4377 default: 4378 rtld_putchar(c); 4379 continue; 4380 case '\\': 4381 switch (c = *fmt) { 4382 case '\0': 4383 continue; 4384 case 'n': 4385 rtld_putchar('\n'); 4386 break; 4387 case 't': 4388 rtld_putchar('\t'); 4389 break; 4390 } 4391 break; 4392 case '%': 4393 switch (c = *fmt) { 4394 case '\0': 4395 continue; 4396 case '%': 4397 default: 4398 rtld_putchar(c); 4399 break; 4400 case 'A': 4401 rtld_putstr(main_local); 4402 break; 4403 case 'a': 4404 rtld_putstr(obj_main->path); 4405 break; 4406 case 'o': 4407 rtld_putstr(name); 4408 break; 4409 #if 0 4410 case 'm': 4411 rtld_printf("%d", sodp->sod_major); 4412 break; 4413 case 'n': 4414 rtld_printf("%d", sodp->sod_minor); 4415 break; 4416 #endif 4417 case 'p': 4418 rtld_putstr(path); 4419 break; 4420 case 'x': 4421 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4422 0); 4423 break; 4424 } 4425 break; 4426 } 4427 ++fmt; 4428 } 4429 } 4430 } 4431 } 4432 4433 /* 4434 * Unload a dlopened object and its dependencies from memory and from 4435 * our data structures. It is assumed that the DAG rooted in the 4436 * object has already been unreferenced, and that the object has a 4437 * reference count of 0. 4438 */ 4439 static void 4440 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4441 { 4442 Obj_Entry marker, *obj, *next; 4443 4444 assert(root->refcount == 0); 4445 4446 /* 4447 * Pass over the DAG removing unreferenced objects from 4448 * appropriate lists. 4449 */ 4450 unlink_object(root); 4451 4452 /* Unmap all objects that are no longer referenced. */ 4453 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4454 next = TAILQ_NEXT(obj, next); 4455 if (obj->marker || obj->refcount != 0) 4456 continue; 4457 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4458 obj->mapsize, 0, obj->path); 4459 dbg("unloading \"%s\"", obj->path); 4460 /* 4461 * Unlink the object now to prevent new references from 4462 * being acquired while the bind lock is dropped in 4463 * recursive dlclose() invocations. 4464 */ 4465 TAILQ_REMOVE(&obj_list, obj, next); 4466 obj_count--; 4467 4468 if (obj->filtees_loaded) { 4469 if (next != NULL) { 4470 init_marker(&marker); 4471 TAILQ_INSERT_BEFORE(next, &marker, next); 4472 unload_filtees(obj, lockstate); 4473 next = TAILQ_NEXT(&marker, next); 4474 TAILQ_REMOVE(&obj_list, &marker, next); 4475 } else 4476 unload_filtees(obj, lockstate); 4477 } 4478 release_object(obj); 4479 } 4480 } 4481 4482 static void 4483 unlink_object(Obj_Entry *root) 4484 { 4485 Objlist_Entry *elm; 4486 4487 if (root->refcount == 0) { 4488 /* Remove the object from the RTLD_GLOBAL list. */ 4489 objlist_remove(&list_global, root); 4490 4491 /* Remove the object from all objects' DAG lists. */ 4492 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4493 objlist_remove(&elm->obj->dldags, root); 4494 if (elm->obj != root) 4495 unlink_object(elm->obj); 4496 } 4497 } 4498 } 4499 4500 static void 4501 ref_dag(Obj_Entry *root) 4502 { 4503 Objlist_Entry *elm; 4504 4505 assert(root->dag_inited); 4506 STAILQ_FOREACH(elm, &root->dagmembers, link) 4507 elm->obj->refcount++; 4508 } 4509 4510 static void 4511 unref_dag(Obj_Entry *root) 4512 { 4513 Objlist_Entry *elm; 4514 4515 assert(root->dag_inited); 4516 STAILQ_FOREACH(elm, &root->dagmembers, link) 4517 elm->obj->refcount--; 4518 } 4519 4520 /* 4521 * Common code for MD __tls_get_addr(). 4522 */ 4523 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4524 static void * 4525 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4526 { 4527 Elf_Addr *newdtv, *dtv; 4528 RtldLockState lockstate; 4529 int to_copy; 4530 4531 dtv = *dtvp; 4532 /* Check dtv generation in case new modules have arrived */ 4533 if (dtv[0] != tls_dtv_generation) { 4534 wlock_acquire(rtld_bind_lock, &lockstate); 4535 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4536 to_copy = dtv[1]; 4537 if (to_copy > tls_max_index) 4538 to_copy = tls_max_index; 4539 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4540 newdtv[0] = tls_dtv_generation; 4541 newdtv[1] = tls_max_index; 4542 free(dtv); 4543 lock_release(rtld_bind_lock, &lockstate); 4544 dtv = *dtvp = newdtv; 4545 } 4546 4547 /* Dynamically allocate module TLS if necessary */ 4548 if (dtv[index + 1] == 0) { 4549 /* Signal safe, wlock will block out signals. */ 4550 wlock_acquire(rtld_bind_lock, &lockstate); 4551 if (!dtv[index + 1]) 4552 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4553 lock_release(rtld_bind_lock, &lockstate); 4554 } 4555 return ((void *)(dtv[index + 1] + offset)); 4556 } 4557 4558 void * 4559 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4560 { 4561 Elf_Addr *dtv; 4562 4563 dtv = *dtvp; 4564 /* Check dtv generation in case new modules have arrived */ 4565 if (__predict_true(dtv[0] == tls_dtv_generation && 4566 dtv[index + 1] != 0)) 4567 return ((void *)(dtv[index + 1] + offset)); 4568 return (tls_get_addr_slow(dtvp, index, offset)); 4569 } 4570 4571 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4572 defined(__powerpc__) || defined(__riscv__) 4573 4574 /* 4575 * Allocate Static TLS using the Variant I method. 4576 */ 4577 void * 4578 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4579 { 4580 Obj_Entry *obj; 4581 char *tcb; 4582 Elf_Addr **tls; 4583 Elf_Addr *dtv; 4584 Elf_Addr addr; 4585 int i; 4586 4587 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4588 return (oldtcb); 4589 4590 assert(tcbsize >= TLS_TCB_SIZE); 4591 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4592 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4593 4594 if (oldtcb != NULL) { 4595 memcpy(tls, oldtcb, tls_static_space); 4596 free(oldtcb); 4597 4598 /* Adjust the DTV. */ 4599 dtv = tls[0]; 4600 for (i = 0; i < dtv[1]; i++) { 4601 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4602 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4603 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4604 } 4605 } 4606 } else { 4607 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4608 tls[0] = dtv; 4609 dtv[0] = tls_dtv_generation; 4610 dtv[1] = tls_max_index; 4611 4612 for (obj = globallist_curr(objs); obj != NULL; 4613 obj = globallist_next(obj)) { 4614 if (obj->tlsoffset > 0) { 4615 addr = (Elf_Addr)tls + obj->tlsoffset; 4616 if (obj->tlsinitsize > 0) 4617 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4618 if (obj->tlssize > obj->tlsinitsize) 4619 memset((void*) (addr + obj->tlsinitsize), 0, 4620 obj->tlssize - obj->tlsinitsize); 4621 dtv[obj->tlsindex + 1] = addr; 4622 } 4623 } 4624 } 4625 4626 return (tcb); 4627 } 4628 4629 void 4630 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4631 { 4632 Elf_Addr *dtv; 4633 Elf_Addr tlsstart, tlsend; 4634 int dtvsize, i; 4635 4636 assert(tcbsize >= TLS_TCB_SIZE); 4637 4638 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4639 tlsend = tlsstart + tls_static_space; 4640 4641 dtv = *(Elf_Addr **)tlsstart; 4642 dtvsize = dtv[1]; 4643 for (i = 0; i < dtvsize; i++) { 4644 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4645 free((void*)dtv[i+2]); 4646 } 4647 } 4648 free(dtv); 4649 free(tcb); 4650 } 4651 4652 #endif 4653 4654 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4655 4656 /* 4657 * Allocate Static TLS using the Variant II method. 4658 */ 4659 void * 4660 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4661 { 4662 Obj_Entry *obj; 4663 size_t size, ralign; 4664 char *tls; 4665 Elf_Addr *dtv, *olddtv; 4666 Elf_Addr segbase, oldsegbase, addr; 4667 int i; 4668 4669 ralign = tcbalign; 4670 if (tls_static_max_align > ralign) 4671 ralign = tls_static_max_align; 4672 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4673 4674 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4675 tls = malloc_aligned(size, ralign); 4676 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4677 4678 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4679 ((Elf_Addr*)segbase)[0] = segbase; 4680 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4681 4682 dtv[0] = tls_dtv_generation; 4683 dtv[1] = tls_max_index; 4684 4685 if (oldtls) { 4686 /* 4687 * Copy the static TLS block over whole. 4688 */ 4689 oldsegbase = (Elf_Addr) oldtls; 4690 memcpy((void *)(segbase - tls_static_space), 4691 (const void *)(oldsegbase - tls_static_space), 4692 tls_static_space); 4693 4694 /* 4695 * If any dynamic TLS blocks have been created tls_get_addr(), 4696 * move them over. 4697 */ 4698 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4699 for (i = 0; i < olddtv[1]; i++) { 4700 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4701 dtv[i+2] = olddtv[i+2]; 4702 olddtv[i+2] = 0; 4703 } 4704 } 4705 4706 /* 4707 * We assume that this block was the one we created with 4708 * allocate_initial_tls(). 4709 */ 4710 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4711 } else { 4712 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4713 if (obj->marker || obj->tlsoffset == 0) 4714 continue; 4715 addr = segbase - obj->tlsoffset; 4716 memset((void*) (addr + obj->tlsinitsize), 4717 0, obj->tlssize - obj->tlsinitsize); 4718 if (obj->tlsinit) 4719 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4720 dtv[obj->tlsindex + 1] = addr; 4721 } 4722 } 4723 4724 return (void*) segbase; 4725 } 4726 4727 void 4728 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4729 { 4730 Elf_Addr* dtv; 4731 size_t size, ralign; 4732 int dtvsize, i; 4733 Elf_Addr tlsstart, tlsend; 4734 4735 /* 4736 * Figure out the size of the initial TLS block so that we can 4737 * find stuff which ___tls_get_addr() allocated dynamically. 4738 */ 4739 ralign = tcbalign; 4740 if (tls_static_max_align > ralign) 4741 ralign = tls_static_max_align; 4742 size = round(tls_static_space, ralign); 4743 4744 dtv = ((Elf_Addr**)tls)[1]; 4745 dtvsize = dtv[1]; 4746 tlsend = (Elf_Addr) tls; 4747 tlsstart = tlsend - size; 4748 for (i = 0; i < dtvsize; i++) { 4749 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4750 free_aligned((void *)dtv[i + 2]); 4751 } 4752 } 4753 4754 free_aligned((void *)tlsstart); 4755 free((void*) dtv); 4756 } 4757 4758 #endif 4759 4760 /* 4761 * Allocate TLS block for module with given index. 4762 */ 4763 void * 4764 allocate_module_tls(int index) 4765 { 4766 Obj_Entry* obj; 4767 char* p; 4768 4769 TAILQ_FOREACH(obj, &obj_list, next) { 4770 if (obj->marker) 4771 continue; 4772 if (obj->tlsindex == index) 4773 break; 4774 } 4775 if (!obj) { 4776 _rtld_error("Can't find module with TLS index %d", index); 4777 rtld_die(); 4778 } 4779 4780 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4781 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4782 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4783 4784 return p; 4785 } 4786 4787 bool 4788 allocate_tls_offset(Obj_Entry *obj) 4789 { 4790 size_t off; 4791 4792 if (obj->tls_done) 4793 return true; 4794 4795 if (obj->tlssize == 0) { 4796 obj->tls_done = true; 4797 return true; 4798 } 4799 4800 if (tls_last_offset == 0) 4801 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4802 else 4803 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4804 obj->tlssize, obj->tlsalign); 4805 4806 /* 4807 * If we have already fixed the size of the static TLS block, we 4808 * must stay within that size. When allocating the static TLS, we 4809 * leave a small amount of space spare to be used for dynamically 4810 * loading modules which use static TLS. 4811 */ 4812 if (tls_static_space != 0) { 4813 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4814 return false; 4815 } else if (obj->tlsalign > tls_static_max_align) { 4816 tls_static_max_align = obj->tlsalign; 4817 } 4818 4819 tls_last_offset = obj->tlsoffset = off; 4820 tls_last_size = obj->tlssize; 4821 obj->tls_done = true; 4822 4823 return true; 4824 } 4825 4826 void 4827 free_tls_offset(Obj_Entry *obj) 4828 { 4829 4830 /* 4831 * If we were the last thing to allocate out of the static TLS 4832 * block, we give our space back to the 'allocator'. This is a 4833 * simplistic workaround to allow libGL.so.1 to be loaded and 4834 * unloaded multiple times. 4835 */ 4836 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4837 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4838 tls_last_offset -= obj->tlssize; 4839 tls_last_size = 0; 4840 } 4841 } 4842 4843 void * 4844 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4845 { 4846 void *ret; 4847 RtldLockState lockstate; 4848 4849 wlock_acquire(rtld_bind_lock, &lockstate); 4850 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4851 tcbsize, tcbalign); 4852 lock_release(rtld_bind_lock, &lockstate); 4853 return (ret); 4854 } 4855 4856 void 4857 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4858 { 4859 RtldLockState lockstate; 4860 4861 wlock_acquire(rtld_bind_lock, &lockstate); 4862 free_tls(tcb, tcbsize, tcbalign); 4863 lock_release(rtld_bind_lock, &lockstate); 4864 } 4865 4866 static void 4867 object_add_name(Obj_Entry *obj, const char *name) 4868 { 4869 Name_Entry *entry; 4870 size_t len; 4871 4872 len = strlen(name); 4873 entry = malloc(sizeof(Name_Entry) + len); 4874 4875 if (entry != NULL) { 4876 strcpy(entry->name, name); 4877 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4878 } 4879 } 4880 4881 static int 4882 object_match_name(const Obj_Entry *obj, const char *name) 4883 { 4884 Name_Entry *entry; 4885 4886 STAILQ_FOREACH(entry, &obj->names, link) { 4887 if (strcmp(name, entry->name) == 0) 4888 return (1); 4889 } 4890 return (0); 4891 } 4892 4893 static Obj_Entry * 4894 locate_dependency(const Obj_Entry *obj, const char *name) 4895 { 4896 const Objlist_Entry *entry; 4897 const Needed_Entry *needed; 4898 4899 STAILQ_FOREACH(entry, &list_main, link) { 4900 if (object_match_name(entry->obj, name)) 4901 return entry->obj; 4902 } 4903 4904 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4905 if (strcmp(obj->strtab + needed->name, name) == 0 || 4906 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4907 /* 4908 * If there is DT_NEEDED for the name we are looking for, 4909 * we are all set. Note that object might not be found if 4910 * dependency was not loaded yet, so the function can 4911 * return NULL here. This is expected and handled 4912 * properly by the caller. 4913 */ 4914 return (needed->obj); 4915 } 4916 } 4917 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4918 obj->path, name); 4919 rtld_die(); 4920 } 4921 4922 static int 4923 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4924 const Elf_Vernaux *vna) 4925 { 4926 const Elf_Verdef *vd; 4927 const char *vername; 4928 4929 vername = refobj->strtab + vna->vna_name; 4930 vd = depobj->verdef; 4931 if (vd == NULL) { 4932 _rtld_error("%s: version %s required by %s not defined", 4933 depobj->path, vername, refobj->path); 4934 return (-1); 4935 } 4936 for (;;) { 4937 if (vd->vd_version != VER_DEF_CURRENT) { 4938 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4939 depobj->path, vd->vd_version); 4940 return (-1); 4941 } 4942 if (vna->vna_hash == vd->vd_hash) { 4943 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4944 ((char *)vd + vd->vd_aux); 4945 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4946 return (0); 4947 } 4948 if (vd->vd_next == 0) 4949 break; 4950 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4951 } 4952 if (vna->vna_flags & VER_FLG_WEAK) 4953 return (0); 4954 _rtld_error("%s: version %s required by %s not found", 4955 depobj->path, vername, refobj->path); 4956 return (-1); 4957 } 4958 4959 static int 4960 rtld_verify_object_versions(Obj_Entry *obj) 4961 { 4962 const Elf_Verneed *vn; 4963 const Elf_Verdef *vd; 4964 const Elf_Verdaux *vda; 4965 const Elf_Vernaux *vna; 4966 const Obj_Entry *depobj; 4967 int maxvernum, vernum; 4968 4969 if (obj->ver_checked) 4970 return (0); 4971 obj->ver_checked = true; 4972 4973 maxvernum = 0; 4974 /* 4975 * Walk over defined and required version records and figure out 4976 * max index used by any of them. Do very basic sanity checking 4977 * while there. 4978 */ 4979 vn = obj->verneed; 4980 while (vn != NULL) { 4981 if (vn->vn_version != VER_NEED_CURRENT) { 4982 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4983 obj->path, vn->vn_version); 4984 return (-1); 4985 } 4986 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4987 for (;;) { 4988 vernum = VER_NEED_IDX(vna->vna_other); 4989 if (vernum > maxvernum) 4990 maxvernum = vernum; 4991 if (vna->vna_next == 0) 4992 break; 4993 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4994 } 4995 if (vn->vn_next == 0) 4996 break; 4997 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4998 } 4999 5000 vd = obj->verdef; 5001 while (vd != NULL) { 5002 if (vd->vd_version != VER_DEF_CURRENT) { 5003 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5004 obj->path, vd->vd_version); 5005 return (-1); 5006 } 5007 vernum = VER_DEF_IDX(vd->vd_ndx); 5008 if (vernum > maxvernum) 5009 maxvernum = vernum; 5010 if (vd->vd_next == 0) 5011 break; 5012 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5013 } 5014 5015 if (maxvernum == 0) 5016 return (0); 5017 5018 /* 5019 * Store version information in array indexable by version index. 5020 * Verify that object version requirements are satisfied along the 5021 * way. 5022 */ 5023 obj->vernum = maxvernum + 1; 5024 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5025 5026 vd = obj->verdef; 5027 while (vd != NULL) { 5028 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5029 vernum = VER_DEF_IDX(vd->vd_ndx); 5030 assert(vernum <= maxvernum); 5031 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5032 obj->vertab[vernum].hash = vd->vd_hash; 5033 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5034 obj->vertab[vernum].file = NULL; 5035 obj->vertab[vernum].flags = 0; 5036 } 5037 if (vd->vd_next == 0) 5038 break; 5039 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5040 } 5041 5042 vn = obj->verneed; 5043 while (vn != NULL) { 5044 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5045 if (depobj == NULL) 5046 return (-1); 5047 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5048 for (;;) { 5049 if (check_object_provided_version(obj, depobj, vna)) 5050 return (-1); 5051 vernum = VER_NEED_IDX(vna->vna_other); 5052 assert(vernum <= maxvernum); 5053 obj->vertab[vernum].hash = vna->vna_hash; 5054 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5055 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5056 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5057 VER_INFO_HIDDEN : 0; 5058 if (vna->vna_next == 0) 5059 break; 5060 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5061 } 5062 if (vn->vn_next == 0) 5063 break; 5064 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5065 } 5066 return 0; 5067 } 5068 5069 static int 5070 rtld_verify_versions(const Objlist *objlist) 5071 { 5072 Objlist_Entry *entry; 5073 int rc; 5074 5075 rc = 0; 5076 STAILQ_FOREACH(entry, objlist, link) { 5077 /* 5078 * Skip dummy objects or objects that have their version requirements 5079 * already checked. 5080 */ 5081 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5082 continue; 5083 if (rtld_verify_object_versions(entry->obj) == -1) { 5084 rc = -1; 5085 if (ld_tracing == NULL) 5086 break; 5087 } 5088 } 5089 if (rc == 0 || ld_tracing != NULL) 5090 rc = rtld_verify_object_versions(&obj_rtld); 5091 return rc; 5092 } 5093 5094 const Ver_Entry * 5095 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5096 { 5097 Elf_Versym vernum; 5098 5099 if (obj->vertab) { 5100 vernum = VER_NDX(obj->versyms[symnum]); 5101 if (vernum >= obj->vernum) { 5102 _rtld_error("%s: symbol %s has wrong verneed value %d", 5103 obj->path, obj->strtab + symnum, vernum); 5104 } else if (obj->vertab[vernum].hash != 0) { 5105 return &obj->vertab[vernum]; 5106 } 5107 } 5108 return NULL; 5109 } 5110 5111 int 5112 _rtld_get_stack_prot(void) 5113 { 5114 5115 return (stack_prot); 5116 } 5117 5118 int 5119 _rtld_is_dlopened(void *arg) 5120 { 5121 Obj_Entry *obj; 5122 RtldLockState lockstate; 5123 int res; 5124 5125 rlock_acquire(rtld_bind_lock, &lockstate); 5126 obj = dlcheck(arg); 5127 if (obj == NULL) 5128 obj = obj_from_addr(arg); 5129 if (obj == NULL) { 5130 _rtld_error("No shared object contains address"); 5131 lock_release(rtld_bind_lock, &lockstate); 5132 return (-1); 5133 } 5134 res = obj->dlopened ? 1 : 0; 5135 lock_release(rtld_bind_lock, &lockstate); 5136 return (res); 5137 } 5138 5139 int 5140 obj_enforce_relro(Obj_Entry *obj) 5141 { 5142 5143 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5144 PROT_READ) == -1) { 5145 _rtld_error("%s: Cannot enforce relro protection: %s", 5146 obj->path, rtld_strerror(errno)); 5147 return (-1); 5148 } 5149 return (0); 5150 } 5151 5152 static void 5153 map_stacks_exec(RtldLockState *lockstate) 5154 { 5155 void (*thr_map_stacks_exec)(void); 5156 5157 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5158 return; 5159 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5160 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5161 if (thr_map_stacks_exec != NULL) { 5162 stack_prot |= PROT_EXEC; 5163 thr_map_stacks_exec(); 5164 } 5165 } 5166 5167 void 5168 symlook_init(SymLook *dst, const char *name) 5169 { 5170 5171 bzero(dst, sizeof(*dst)); 5172 dst->name = name; 5173 dst->hash = elf_hash(name); 5174 dst->hash_gnu = gnu_hash(name); 5175 } 5176 5177 static void 5178 symlook_init_from_req(SymLook *dst, const SymLook *src) 5179 { 5180 5181 dst->name = src->name; 5182 dst->hash = src->hash; 5183 dst->hash_gnu = src->hash_gnu; 5184 dst->ventry = src->ventry; 5185 dst->flags = src->flags; 5186 dst->defobj_out = NULL; 5187 dst->sym_out = NULL; 5188 dst->lockstate = src->lockstate; 5189 } 5190 5191 5192 /* 5193 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5194 */ 5195 static int 5196 parse_libdir(const char *str) 5197 { 5198 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5199 const char *orig; 5200 int fd; 5201 char c; 5202 5203 orig = str; 5204 fd = 0; 5205 for (c = *str; c != '\0'; c = *++str) { 5206 if (c < '0' || c > '9') 5207 return (-1); 5208 5209 fd *= RADIX; 5210 fd += c - '0'; 5211 } 5212 5213 /* Make sure we actually parsed something. */ 5214 if (str == orig) { 5215 _rtld_error("failed to parse directory FD from '%s'", str); 5216 return (-1); 5217 } 5218 return (fd); 5219 } 5220 5221 /* 5222 * Overrides for libc_pic-provided functions. 5223 */ 5224 5225 int 5226 __getosreldate(void) 5227 { 5228 size_t len; 5229 int oid[2]; 5230 int error, osrel; 5231 5232 if (osreldate != 0) 5233 return (osreldate); 5234 5235 oid[0] = CTL_KERN; 5236 oid[1] = KERN_OSRELDATE; 5237 osrel = 0; 5238 len = sizeof(osrel); 5239 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5240 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5241 osreldate = osrel; 5242 return (osreldate); 5243 } 5244 5245 void 5246 exit(int status) 5247 { 5248 5249 _exit(status); 5250 } 5251 5252 void (*__cleanup)(void); 5253 int __isthreaded = 0; 5254 int _thread_autoinit_dummy_decl = 1; 5255 5256 /* 5257 * No unresolved symbols for rtld. 5258 */ 5259 void 5260 __pthread_cxa_finalize(struct dl_phdr_info *a) 5261 { 5262 } 5263 5264 void 5265 __stack_chk_fail(void) 5266 { 5267 5268 _rtld_error("stack overflow detected; terminated"); 5269 rtld_die(); 5270 } 5271 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5272 5273 void 5274 __chk_fail(void) 5275 { 5276 5277 _rtld_error("buffer overflow detected; terminated"); 5278 rtld_die(); 5279 } 5280 5281 const char * 5282 rtld_strerror(int errnum) 5283 { 5284 5285 if (errnum < 0 || errnum >= sys_nerr) 5286 return ("Unknown error"); 5287 return (sys_errlist[errnum]); 5288 } 5289