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 "notes.h" 63 64 /* Types. */ 65 typedef void (*func_ptr_type)(); 66 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 67 68 /* 69 * Function declarations. 70 */ 71 static const char *basename(const char *); 72 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 73 const Elf_Dyn **, const Elf_Dyn **); 74 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 75 const Elf_Dyn *); 76 static void digest_dynamic(Obj_Entry *, int); 77 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 78 static Obj_Entry *dlcheck(void *); 79 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 80 int lo_flags, int mode, RtldLockState *lockstate); 81 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 82 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 83 static bool donelist_check(DoneList *, const Obj_Entry *); 84 static void errmsg_restore(char *); 85 static char *errmsg_save(void); 86 static void *fill_search_info(const char *, size_t, void *); 87 static char *find_library(const char *, const Obj_Entry *, int *); 88 static const char *gethints(bool); 89 static void init_dag(Obj_Entry *); 90 static void init_pagesizes(Elf_Auxinfo **aux_info); 91 static void init_rtld(caddr_t, Elf_Auxinfo **); 92 static void initlist_add_neededs(Needed_Entry *, Objlist *); 93 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 94 static void linkmap_add(Obj_Entry *); 95 static void linkmap_delete(Obj_Entry *); 96 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 97 static void unload_filtees(Obj_Entry *); 98 static int load_needed_objects(Obj_Entry *, int); 99 static int load_preload_objects(void); 100 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 101 static void map_stacks_exec(RtldLockState *); 102 static Obj_Entry *obj_from_addr(const void *); 103 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 104 static void objlist_call_init(Objlist *, RtldLockState *); 105 static void objlist_clear(Objlist *); 106 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 107 static void objlist_init(Objlist *); 108 static void objlist_push_head(Objlist *, Obj_Entry *); 109 static void objlist_push_tail(Objlist *, Obj_Entry *); 110 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 111 static void objlist_remove(Objlist *, Obj_Entry *); 112 static int parse_libdir(const char *); 113 static void *path_enumerate(const char *, path_enum_proc, void *); 114 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 115 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 116 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 117 int flags, RtldLockState *lockstate); 118 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 119 RtldLockState *); 120 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 121 int flags, RtldLockState *lockstate); 122 static int rtld_dirname(const char *, char *); 123 static int rtld_dirname_abs(const char *, char *); 124 static void *rtld_dlopen(const char *name, int fd, int mode); 125 static void rtld_exit(void); 126 static char *search_library_path(const char *, const char *); 127 static char *search_library_pathfds(const char *, const char *, int *); 128 static const void **get_program_var_addr(const char *, RtldLockState *); 129 static void set_program_var(const char *, const void *); 130 static int symlook_default(SymLook *, const Obj_Entry *refobj); 131 static int symlook_global(SymLook *, DoneList *); 132 static void symlook_init_from_req(SymLook *, const SymLook *); 133 static int symlook_list(SymLook *, const Objlist *, DoneList *); 134 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 135 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 136 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 137 static void trace_loaded_objects(Obj_Entry *); 138 static void unlink_object(Obj_Entry *); 139 static void unload_object(Obj_Entry *); 140 static void unref_dag(Obj_Entry *); 141 static void ref_dag(Obj_Entry *); 142 static char *origin_subst_one(Obj_Entry *, char *, const char *, 143 const char *, bool); 144 static char *origin_subst(Obj_Entry *, char *); 145 static bool obj_resolve_origin(Obj_Entry *obj); 146 static void preinit_main(void); 147 static int rtld_verify_versions(const Objlist *); 148 static int rtld_verify_object_versions(Obj_Entry *); 149 static void object_add_name(Obj_Entry *, const char *); 150 static int object_match_name(const Obj_Entry *, const char *); 151 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 152 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 153 struct dl_phdr_info *phdr_info); 154 static uint32_t gnu_hash(const char *); 155 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 156 const unsigned long); 157 158 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 159 void _r_debug_postinit(struct link_map *) __noinline __exported; 160 161 int __sys_openat(int, const char *, int, ...); 162 163 /* 164 * Data declarations. 165 */ 166 static char *error_message; /* Message for dlerror(), or NULL */ 167 struct r_debug r_debug __exported; /* for GDB; */ 168 static bool libmap_disable; /* Disable libmap */ 169 static bool ld_loadfltr; /* Immediate filters processing */ 170 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 171 static bool trust; /* False for setuid and setgid programs */ 172 static bool dangerous_ld_env; /* True if environment variables have been 173 used to affect the libraries loaded */ 174 static char *ld_bind_now; /* Environment variable for immediate binding */ 175 static char *ld_debug; /* Environment variable for debugging */ 176 static char *ld_library_path; /* Environment variable for search path */ 177 static char *ld_library_dirs; /* Environment variable for library descriptors */ 178 static char *ld_preload; /* Environment variable for libraries to 179 load first */ 180 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 181 static char *ld_tracing; /* Called from ldd to print libs */ 182 static char *ld_utrace; /* Use utrace() to log events. */ 183 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 184 static Obj_Entry *obj_main; /* The main program shared object */ 185 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 186 static unsigned int obj_count; /* Number of objects in obj_list */ 187 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 188 189 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 190 STAILQ_HEAD_INITIALIZER(list_global); 191 static Objlist list_main = /* Objects loaded at program startup */ 192 STAILQ_HEAD_INITIALIZER(list_main); 193 static Objlist list_fini = /* Objects needing fini() calls */ 194 STAILQ_HEAD_INITIALIZER(list_fini); 195 196 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 197 198 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 199 200 extern Elf_Dyn _DYNAMIC; 201 #pragma weak _DYNAMIC 202 #ifndef RTLD_IS_DYNAMIC 203 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 204 #endif 205 206 int dlclose(void *) __exported; 207 char *dlerror(void) __exported; 208 void *dlopen(const char *, int) __exported; 209 void *fdlopen(int, int) __exported; 210 void *dlsym(void *, const char *) __exported; 211 dlfunc_t dlfunc(void *, const char *) __exported; 212 void *dlvsym(void *, const char *, const char *) __exported; 213 int dladdr(const void *, Dl_info *) __exported; 214 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 215 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 216 int dlinfo(void *, int , void *) __exported; 217 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 218 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 219 int _rtld_get_stack_prot(void) __exported; 220 int _rtld_is_dlopened(void *) __exported; 221 void _rtld_error(const char *, ...) __exported; 222 223 int npagesizes, osreldate; 224 size_t *pagesizes; 225 226 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 227 228 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 229 static int max_stack_flags; 230 231 /* 232 * Global declarations normally provided by crt1. The dynamic linker is 233 * not built with crt1, so we have to provide them ourselves. 234 */ 235 char *__progname; 236 char **environ; 237 238 /* 239 * Used to pass argc, argv to init functions. 240 */ 241 int main_argc; 242 char **main_argv; 243 244 /* 245 * Globals to control TLS allocation. 246 */ 247 size_t tls_last_offset; /* Static TLS offset of last module */ 248 size_t tls_last_size; /* Static TLS size of last module */ 249 size_t tls_static_space; /* Static TLS space allocated */ 250 size_t tls_static_max_align; 251 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 252 int tls_max_index = 1; /* Largest module index allocated */ 253 254 bool ld_library_path_rpath = false; 255 256 /* 257 * Globals for path names, and such 258 */ 259 char *ld_elf_hints_default = _PATH_ELF_HINTS; 260 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 261 char *ld_path_rtld = _PATH_RTLD; 262 char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 263 char *ld_env_prefix = LD_; 264 265 /* 266 * Fill in a DoneList with an allocation large enough to hold all of 267 * the currently-loaded objects. Keep this as a macro since it calls 268 * alloca and we want that to occur within the scope of the caller. 269 */ 270 #define donelist_init(dlp) \ 271 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 272 assert((dlp)->objs != NULL), \ 273 (dlp)->num_alloc = obj_count, \ 274 (dlp)->num_used = 0) 275 276 #define UTRACE_DLOPEN_START 1 277 #define UTRACE_DLOPEN_STOP 2 278 #define UTRACE_DLCLOSE_START 3 279 #define UTRACE_DLCLOSE_STOP 4 280 #define UTRACE_LOAD_OBJECT 5 281 #define UTRACE_UNLOAD_OBJECT 6 282 #define UTRACE_ADD_RUNDEP 7 283 #define UTRACE_PRELOAD_FINISHED 8 284 #define UTRACE_INIT_CALL 9 285 #define UTRACE_FINI_CALL 10 286 #define UTRACE_DLSYM_START 11 287 #define UTRACE_DLSYM_STOP 12 288 289 struct utrace_rtld { 290 char sig[4]; /* 'RTLD' */ 291 int event; 292 void *handle; 293 void *mapbase; /* Used for 'parent' and 'init/fini' */ 294 size_t mapsize; 295 int refcnt; /* Used for 'mode' */ 296 char name[MAXPATHLEN]; 297 }; 298 299 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 300 if (ld_utrace != NULL) \ 301 ld_utrace_log(e, h, mb, ms, r, n); \ 302 } while (0) 303 304 static void 305 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 306 int refcnt, const char *name) 307 { 308 struct utrace_rtld ut; 309 310 ut.sig[0] = 'R'; 311 ut.sig[1] = 'T'; 312 ut.sig[2] = 'L'; 313 ut.sig[3] = 'D'; 314 ut.event = event; 315 ut.handle = handle; 316 ut.mapbase = mapbase; 317 ut.mapsize = mapsize; 318 ut.refcnt = refcnt; 319 bzero(ut.name, sizeof(ut.name)); 320 if (name) 321 strlcpy(ut.name, name, sizeof(ut.name)); 322 utrace(&ut, sizeof(ut)); 323 } 324 325 #ifdef RTLD_VARIANT_ENV_NAMES 326 /* 327 * construct the env variable based on the type of binary that's 328 * running. 329 */ 330 static inline const char * 331 _LD(const char *var) 332 { 333 static char buffer[128]; 334 335 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 336 strlcat(buffer, var, sizeof(buffer)); 337 return (buffer); 338 } 339 #else 340 #define _LD(x) LD_ x 341 #endif 342 343 /* 344 * Main entry point for dynamic linking. The first argument is the 345 * stack pointer. The stack is expected to be laid out as described 346 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 347 * Specifically, the stack pointer points to a word containing 348 * ARGC. Following that in the stack is a null-terminated sequence 349 * of pointers to argument strings. Then comes a null-terminated 350 * sequence of pointers to environment strings. Finally, there is a 351 * sequence of "auxiliary vector" entries. 352 * 353 * The second argument points to a place to store the dynamic linker's 354 * exit procedure pointer and the third to a place to store the main 355 * program's object. 356 * 357 * The return value is the main program's entry point. 358 */ 359 func_ptr_type 360 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 361 { 362 Elf_Auxinfo *aux_info[AT_COUNT]; 363 int i; 364 int argc; 365 char **argv; 366 char **env; 367 Elf_Auxinfo *aux; 368 Elf_Auxinfo *auxp; 369 const char *argv0; 370 Objlist_Entry *entry; 371 Obj_Entry *obj; 372 Obj_Entry *preload_tail; 373 Obj_Entry *last_interposer; 374 Objlist initlist; 375 RtldLockState lockstate; 376 char *library_path_rpath; 377 int mib[2]; 378 size_t len; 379 380 /* 381 * On entry, the dynamic linker itself has not been relocated yet. 382 * Be very careful not to reference any global data until after 383 * init_rtld has returned. It is OK to reference file-scope statics 384 * and string constants, and to call static and global functions. 385 */ 386 387 /* Find the auxiliary vector on the stack. */ 388 argc = *sp++; 389 argv = (char **) sp; 390 sp += argc + 1; /* Skip over arguments and NULL terminator */ 391 env = (char **) sp; 392 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 393 ; 394 aux = (Elf_Auxinfo *) sp; 395 396 /* Digest the auxiliary vector. */ 397 for (i = 0; i < AT_COUNT; i++) 398 aux_info[i] = NULL; 399 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 400 if (auxp->a_type < AT_COUNT) 401 aux_info[auxp->a_type] = auxp; 402 } 403 404 /* Initialize and relocate ourselves. */ 405 assert(aux_info[AT_BASE] != NULL); 406 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 407 408 __progname = obj_rtld.path; 409 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 410 environ = env; 411 main_argc = argc; 412 main_argv = argv; 413 414 if (aux_info[AT_CANARY] != NULL && 415 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 416 i = aux_info[AT_CANARYLEN]->a_un.a_val; 417 if (i > sizeof(__stack_chk_guard)) 418 i = sizeof(__stack_chk_guard); 419 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 420 } else { 421 mib[0] = CTL_KERN; 422 mib[1] = KERN_ARND; 423 424 len = sizeof(__stack_chk_guard); 425 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 426 len != sizeof(__stack_chk_guard)) { 427 /* If sysctl was unsuccessful, use the "terminator canary". */ 428 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 429 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 430 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 431 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 432 } 433 } 434 435 trust = !issetugid(); 436 437 md_abi_variant_hook(aux_info); 438 439 ld_bind_now = getenv(_LD("BIND_NOW")); 440 /* 441 * If the process is tainted, then we un-set the dangerous environment 442 * variables. The process will be marked as tainted until setuid(2) 443 * is called. If any child process calls setuid(2) we do not want any 444 * future processes to honor the potentially un-safe variables. 445 */ 446 if (!trust) { 447 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 448 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 449 unsetenv(_LD("LIBMAP_DISABLE")) || 450 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 451 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 452 _rtld_error("environment corrupt; aborting"); 453 rtld_die(); 454 } 455 } 456 ld_debug = getenv(_LD("DEBUG")); 457 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 458 libmap_override = getenv(_LD("LIBMAP")); 459 ld_library_path = getenv(_LD("LIBRARY_PATH")); 460 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 461 ld_preload = getenv(_LD("PRELOAD")); 462 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 463 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 464 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 465 if (library_path_rpath != NULL) { 466 if (library_path_rpath[0] == 'y' || 467 library_path_rpath[0] == 'Y' || 468 library_path_rpath[0] == '1') 469 ld_library_path_rpath = true; 470 else 471 ld_library_path_rpath = false; 472 } 473 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 474 (ld_library_path != NULL) || (ld_preload != NULL) || 475 (ld_elf_hints_path != NULL) || ld_loadfltr; 476 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 477 ld_utrace = getenv(_LD("UTRACE")); 478 479 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 480 ld_elf_hints_path = ld_elf_hints_default; 481 482 if (ld_debug != NULL && *ld_debug != '\0') 483 debug = 1; 484 dbg("%s is initialized, base address = %p", __progname, 485 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 486 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 487 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 488 489 dbg("initializing thread locks"); 490 lockdflt_init(); 491 492 /* 493 * Load the main program, or process its program header if it is 494 * already loaded. 495 */ 496 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 497 int fd = aux_info[AT_EXECFD]->a_un.a_val; 498 dbg("loading main program"); 499 obj_main = map_object(fd, argv0, NULL); 500 close(fd); 501 if (obj_main == NULL) 502 rtld_die(); 503 max_stack_flags = obj->stack_flags; 504 } else { /* Main program already loaded. */ 505 const Elf_Phdr *phdr; 506 int phnum; 507 caddr_t entry; 508 509 dbg("processing main program's program header"); 510 assert(aux_info[AT_PHDR] != NULL); 511 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 512 assert(aux_info[AT_PHNUM] != NULL); 513 phnum = aux_info[AT_PHNUM]->a_un.a_val; 514 assert(aux_info[AT_PHENT] != NULL); 515 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 516 assert(aux_info[AT_ENTRY] != NULL); 517 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 518 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 519 rtld_die(); 520 } 521 522 if (aux_info[AT_EXECPATH] != NULL) { 523 char *kexecpath; 524 char buf[MAXPATHLEN]; 525 526 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 527 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 528 if (kexecpath[0] == '/') 529 obj_main->path = kexecpath; 530 else if (getcwd(buf, sizeof(buf)) == NULL || 531 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 532 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 533 obj_main->path = xstrdup(argv0); 534 else 535 obj_main->path = xstrdup(buf); 536 } else { 537 dbg("No AT_EXECPATH"); 538 obj_main->path = xstrdup(argv0); 539 } 540 dbg("obj_main path %s", obj_main->path); 541 obj_main->mainprog = true; 542 543 if (aux_info[AT_STACKPROT] != NULL && 544 aux_info[AT_STACKPROT]->a_un.a_val != 0) 545 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 546 547 #ifndef COMPAT_32BIT 548 /* 549 * Get the actual dynamic linker pathname from the executable if 550 * possible. (It should always be possible.) That ensures that 551 * gdb will find the right dynamic linker even if a non-standard 552 * one is being used. 553 */ 554 if (obj_main->interp != NULL && 555 strcmp(obj_main->interp, obj_rtld.path) != 0) { 556 free(obj_rtld.path); 557 obj_rtld.path = xstrdup(obj_main->interp); 558 __progname = obj_rtld.path; 559 } 560 #endif 561 562 digest_dynamic(obj_main, 0); 563 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 564 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 565 obj_main->dynsymcount); 566 567 linkmap_add(obj_main); 568 linkmap_add(&obj_rtld); 569 570 /* Link the main program into the list of objects. */ 571 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 572 obj_count++; 573 obj_loads++; 574 575 /* Initialize a fake symbol for resolving undefined weak references. */ 576 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 577 sym_zero.st_shndx = SHN_UNDEF; 578 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 579 580 if (!libmap_disable) 581 libmap_disable = (bool)lm_init(libmap_override); 582 583 dbg("loading LD_PRELOAD libraries"); 584 if (load_preload_objects() == -1) 585 rtld_die(); 586 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 587 588 dbg("loading needed objects"); 589 if (load_needed_objects(obj_main, 0) == -1) 590 rtld_die(); 591 592 /* Make a list of all objects loaded at startup. */ 593 last_interposer = obj_main; 594 TAILQ_FOREACH(obj, &obj_list, next) { 595 if (obj->marker) 596 continue; 597 if (obj->z_interpose && obj != obj_main) { 598 objlist_put_after(&list_main, last_interposer, obj); 599 last_interposer = obj; 600 } else { 601 objlist_push_tail(&list_main, obj); 602 } 603 obj->refcount++; 604 } 605 606 dbg("checking for required versions"); 607 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 608 rtld_die(); 609 610 if (ld_tracing) { /* We're done */ 611 trace_loaded_objects(obj_main); 612 exit(0); 613 } 614 615 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 616 dump_relocations(obj_main); 617 exit (0); 618 } 619 620 /* 621 * Processing tls relocations requires having the tls offsets 622 * initialized. Prepare offsets before starting initial 623 * relocation processing. 624 */ 625 dbg("initializing initial thread local storage offsets"); 626 STAILQ_FOREACH(entry, &list_main, link) { 627 /* 628 * Allocate all the initial objects out of the static TLS 629 * block even if they didn't ask for it. 630 */ 631 allocate_tls_offset(entry->obj); 632 } 633 634 if (relocate_objects(obj_main, 635 ld_bind_now != NULL && *ld_bind_now != '\0', 636 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 637 rtld_die(); 638 639 dbg("doing copy relocations"); 640 if (do_copy_relocations(obj_main) == -1) 641 rtld_die(); 642 643 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 644 dump_relocations(obj_main); 645 exit (0); 646 } 647 648 /* 649 * Setup TLS for main thread. This must be done after the 650 * relocations are processed, since tls initialization section 651 * might be the subject for relocations. 652 */ 653 dbg("initializing initial thread local storage"); 654 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 655 656 dbg("initializing key program variables"); 657 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 658 set_program_var("environ", env); 659 set_program_var("__elf_aux_vector", aux); 660 661 /* Make a list of init functions to call. */ 662 objlist_init(&initlist); 663 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 664 preload_tail, &initlist); 665 666 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 667 668 map_stacks_exec(NULL); 669 670 dbg("resolving ifuncs"); 671 if (resolve_objects_ifunc(obj_main, 672 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 673 NULL) == -1) 674 rtld_die(); 675 676 if (!obj_main->crt_no_init) { 677 /* 678 * Make sure we don't call the main program's init and fini 679 * functions for binaries linked with old crt1 which calls 680 * _init itself. 681 */ 682 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 683 obj_main->preinit_array = obj_main->init_array = 684 obj_main->fini_array = (Elf_Addr)NULL; 685 } 686 687 wlock_acquire(rtld_bind_lock, &lockstate); 688 if (obj_main->crt_no_init) 689 preinit_main(); 690 objlist_call_init(&initlist, &lockstate); 691 _r_debug_postinit(&obj_main->linkmap); 692 objlist_clear(&initlist); 693 dbg("loading filtees"); 694 TAILQ_FOREACH(obj, &obj_list, next) { 695 if (obj->marker) 696 continue; 697 if (ld_loadfltr || obj->z_loadfltr) 698 load_filtees(obj, 0, &lockstate); 699 } 700 lock_release(rtld_bind_lock, &lockstate); 701 702 dbg("transferring control to program entry point = %p", obj_main->entry); 703 704 /* Return the exit procedure and the program entry point. */ 705 *exit_proc = rtld_exit; 706 *objp = obj_main; 707 return (func_ptr_type) obj_main->entry; 708 } 709 710 void * 711 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 712 { 713 void *ptr; 714 Elf_Addr target; 715 716 ptr = (void *)make_function_pointer(def, obj); 717 target = ((Elf_Addr (*)(void))ptr)(); 718 return ((void *)target); 719 } 720 721 Elf_Addr 722 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 723 { 724 const Elf_Rel *rel; 725 const Elf_Sym *def; 726 const Obj_Entry *defobj; 727 Elf_Addr *where; 728 Elf_Addr target; 729 RtldLockState lockstate; 730 731 rlock_acquire(rtld_bind_lock, &lockstate); 732 if (sigsetjmp(lockstate.env, 0) != 0) 733 lock_upgrade(rtld_bind_lock, &lockstate); 734 if (obj->pltrel) 735 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 736 else 737 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 738 739 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 740 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 741 &lockstate); 742 if (def == NULL) 743 rtld_die(); 744 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 745 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 746 else 747 target = (Elf_Addr)(defobj->relocbase + def->st_value); 748 749 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 750 defobj->strtab + def->st_name, basename(obj->path), 751 (void *)target, basename(defobj->path)); 752 753 /* 754 * Write the new contents for the jmpslot. Note that depending on 755 * architecture, the value which we need to return back to the 756 * lazy binding trampoline may or may not be the target 757 * address. The value returned from reloc_jmpslot() is the value 758 * that the trampoline needs. 759 */ 760 target = reloc_jmpslot(where, target, defobj, obj, rel); 761 lock_release(rtld_bind_lock, &lockstate); 762 return target; 763 } 764 765 /* 766 * Error reporting function. Use it like printf. If formats the message 767 * into a buffer, and sets things up so that the next call to dlerror() 768 * will return the message. 769 */ 770 void 771 _rtld_error(const char *fmt, ...) 772 { 773 static char buf[512]; 774 va_list ap; 775 776 va_start(ap, fmt); 777 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 778 error_message = buf; 779 va_end(ap); 780 } 781 782 /* 783 * Return a dynamically-allocated copy of the current error message, if any. 784 */ 785 static char * 786 errmsg_save(void) 787 { 788 return error_message == NULL ? NULL : xstrdup(error_message); 789 } 790 791 /* 792 * Restore the current error message from a copy which was previously saved 793 * by errmsg_save(). The copy is freed. 794 */ 795 static void 796 errmsg_restore(char *saved_msg) 797 { 798 if (saved_msg == NULL) 799 error_message = NULL; 800 else { 801 _rtld_error("%s", saved_msg); 802 free(saved_msg); 803 } 804 } 805 806 static const char * 807 basename(const char *name) 808 { 809 const char *p = strrchr(name, '/'); 810 return p != NULL ? p + 1 : name; 811 } 812 813 static struct utsname uts; 814 815 static char * 816 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 817 const char *subst, bool may_free) 818 { 819 char *p, *p1, *res, *resp; 820 int subst_len, kw_len, subst_count, old_len, new_len; 821 822 kw_len = strlen(kw); 823 824 /* 825 * First, count the number of the keyword occurrences, to 826 * preallocate the final string. 827 */ 828 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 829 p1 = strstr(p, kw); 830 if (p1 == NULL) 831 break; 832 } 833 834 /* 835 * If the keyword is not found, just return. 836 * 837 * Return non-substituted string if resolution failed. We 838 * cannot do anything more reasonable, the failure mode of the 839 * caller is unresolved library anyway. 840 */ 841 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 842 return (may_free ? real : xstrdup(real)); 843 if (obj != NULL) 844 subst = obj->origin_path; 845 846 /* 847 * There is indeed something to substitute. Calculate the 848 * length of the resulting string, and allocate it. 849 */ 850 subst_len = strlen(subst); 851 old_len = strlen(real); 852 new_len = old_len + (subst_len - kw_len) * subst_count; 853 res = xmalloc(new_len + 1); 854 855 /* 856 * Now, execute the substitution loop. 857 */ 858 for (p = real, resp = res, *resp = '\0';;) { 859 p1 = strstr(p, kw); 860 if (p1 != NULL) { 861 /* Copy the prefix before keyword. */ 862 memcpy(resp, p, p1 - p); 863 resp += p1 - p; 864 /* Keyword replacement. */ 865 memcpy(resp, subst, subst_len); 866 resp += subst_len; 867 *resp = '\0'; 868 p = p1 + kw_len; 869 } else 870 break; 871 } 872 873 /* Copy to the end of string and finish. */ 874 strcat(resp, p); 875 if (may_free) 876 free(real); 877 return (res); 878 } 879 880 static char * 881 origin_subst(Obj_Entry *obj, char *real) 882 { 883 char *res1, *res2, *res3, *res4; 884 885 if (obj == NULL || !trust) 886 return (xstrdup(real)); 887 if (uts.sysname[0] == '\0') { 888 if (uname(&uts) != 0) { 889 _rtld_error("utsname failed: %d", errno); 890 return (NULL); 891 } 892 } 893 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 894 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 895 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 896 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 897 return (res4); 898 } 899 900 void 901 rtld_die(void) 902 { 903 const char *msg = dlerror(); 904 905 if (msg == NULL) 906 msg = "Fatal error"; 907 rtld_fdputstr(STDERR_FILENO, msg); 908 rtld_fdputchar(STDERR_FILENO, '\n'); 909 _exit(1); 910 } 911 912 /* 913 * Process a shared object's DYNAMIC section, and save the important 914 * information in its Obj_Entry structure. 915 */ 916 static void 917 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 918 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 919 { 920 const Elf_Dyn *dynp; 921 Needed_Entry **needed_tail = &obj->needed; 922 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 923 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 924 const Elf_Hashelt *hashtab; 925 const Elf32_Word *hashval; 926 Elf32_Word bkt, nmaskwords; 927 int bloom_size32; 928 int plttype = DT_REL; 929 930 *dyn_rpath = NULL; 931 *dyn_soname = NULL; 932 *dyn_runpath = NULL; 933 934 obj->bind_now = false; 935 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 936 switch (dynp->d_tag) { 937 938 case DT_REL: 939 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 940 break; 941 942 case DT_RELSZ: 943 obj->relsize = dynp->d_un.d_val; 944 break; 945 946 case DT_RELENT: 947 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 948 break; 949 950 case DT_JMPREL: 951 obj->pltrel = (const Elf_Rel *) 952 (obj->relocbase + dynp->d_un.d_ptr); 953 break; 954 955 case DT_PLTRELSZ: 956 obj->pltrelsize = dynp->d_un.d_val; 957 break; 958 959 case DT_RELA: 960 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 961 break; 962 963 case DT_RELASZ: 964 obj->relasize = dynp->d_un.d_val; 965 break; 966 967 case DT_RELAENT: 968 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 969 break; 970 971 case DT_PLTREL: 972 plttype = dynp->d_un.d_val; 973 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 974 break; 975 976 case DT_SYMTAB: 977 obj->symtab = (const Elf_Sym *) 978 (obj->relocbase + dynp->d_un.d_ptr); 979 break; 980 981 case DT_SYMENT: 982 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 983 break; 984 985 case DT_STRTAB: 986 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 987 break; 988 989 case DT_STRSZ: 990 obj->strsize = dynp->d_un.d_val; 991 break; 992 993 case DT_VERNEED: 994 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 995 dynp->d_un.d_val); 996 break; 997 998 case DT_VERNEEDNUM: 999 obj->verneednum = dynp->d_un.d_val; 1000 break; 1001 1002 case DT_VERDEF: 1003 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1004 dynp->d_un.d_val); 1005 break; 1006 1007 case DT_VERDEFNUM: 1008 obj->verdefnum = dynp->d_un.d_val; 1009 break; 1010 1011 case DT_VERSYM: 1012 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1013 dynp->d_un.d_val); 1014 break; 1015 1016 case DT_HASH: 1017 { 1018 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1019 dynp->d_un.d_ptr); 1020 obj->nbuckets = hashtab[0]; 1021 obj->nchains = hashtab[1]; 1022 obj->buckets = hashtab + 2; 1023 obj->chains = obj->buckets + obj->nbuckets; 1024 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1025 obj->buckets != NULL; 1026 } 1027 break; 1028 1029 case DT_GNU_HASH: 1030 { 1031 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1032 dynp->d_un.d_ptr); 1033 obj->nbuckets_gnu = hashtab[0]; 1034 obj->symndx_gnu = hashtab[1]; 1035 nmaskwords = hashtab[2]; 1036 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1037 obj->maskwords_bm_gnu = nmaskwords - 1; 1038 obj->shift2_gnu = hashtab[3]; 1039 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1040 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1041 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1042 obj->symndx_gnu; 1043 /* Number of bitmask words is required to be power of 2 */ 1044 obj->valid_hash_gnu = powerof2(nmaskwords) && 1045 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1046 } 1047 break; 1048 1049 case DT_NEEDED: 1050 if (!obj->rtld) { 1051 Needed_Entry *nep = NEW(Needed_Entry); 1052 nep->name = dynp->d_un.d_val; 1053 nep->obj = NULL; 1054 nep->next = NULL; 1055 1056 *needed_tail = nep; 1057 needed_tail = &nep->next; 1058 } 1059 break; 1060 1061 case DT_FILTER: 1062 if (!obj->rtld) { 1063 Needed_Entry *nep = NEW(Needed_Entry); 1064 nep->name = dynp->d_un.d_val; 1065 nep->obj = NULL; 1066 nep->next = NULL; 1067 1068 *needed_filtees_tail = nep; 1069 needed_filtees_tail = &nep->next; 1070 } 1071 break; 1072 1073 case DT_AUXILIARY: 1074 if (!obj->rtld) { 1075 Needed_Entry *nep = NEW(Needed_Entry); 1076 nep->name = dynp->d_un.d_val; 1077 nep->obj = NULL; 1078 nep->next = NULL; 1079 1080 *needed_aux_filtees_tail = nep; 1081 needed_aux_filtees_tail = &nep->next; 1082 } 1083 break; 1084 1085 case DT_PLTGOT: 1086 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1087 break; 1088 1089 case DT_TEXTREL: 1090 obj->textrel = true; 1091 break; 1092 1093 case DT_SYMBOLIC: 1094 obj->symbolic = true; 1095 break; 1096 1097 case DT_RPATH: 1098 /* 1099 * We have to wait until later to process this, because we 1100 * might not have gotten the address of the string table yet. 1101 */ 1102 *dyn_rpath = dynp; 1103 break; 1104 1105 case DT_SONAME: 1106 *dyn_soname = dynp; 1107 break; 1108 1109 case DT_RUNPATH: 1110 *dyn_runpath = dynp; 1111 break; 1112 1113 case DT_INIT: 1114 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1115 break; 1116 1117 case DT_PREINIT_ARRAY: 1118 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1119 break; 1120 1121 case DT_PREINIT_ARRAYSZ: 1122 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1123 break; 1124 1125 case DT_INIT_ARRAY: 1126 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1127 break; 1128 1129 case DT_INIT_ARRAYSZ: 1130 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1131 break; 1132 1133 case DT_FINI: 1134 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1135 break; 1136 1137 case DT_FINI_ARRAY: 1138 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1139 break; 1140 1141 case DT_FINI_ARRAYSZ: 1142 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1143 break; 1144 1145 /* 1146 * Don't process DT_DEBUG on MIPS as the dynamic section 1147 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1148 */ 1149 1150 #ifndef __mips__ 1151 case DT_DEBUG: 1152 if (!early) 1153 dbg("Filling in DT_DEBUG entry"); 1154 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1155 break; 1156 #endif 1157 1158 case DT_FLAGS: 1159 if (dynp->d_un.d_val & DF_ORIGIN) 1160 obj->z_origin = true; 1161 if (dynp->d_un.d_val & DF_SYMBOLIC) 1162 obj->symbolic = true; 1163 if (dynp->d_un.d_val & DF_TEXTREL) 1164 obj->textrel = true; 1165 if (dynp->d_un.d_val & DF_BIND_NOW) 1166 obj->bind_now = true; 1167 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1168 ;*/ 1169 break; 1170 #ifdef __mips__ 1171 case DT_MIPS_LOCAL_GOTNO: 1172 obj->local_gotno = dynp->d_un.d_val; 1173 break; 1174 1175 case DT_MIPS_SYMTABNO: 1176 obj->symtabno = dynp->d_un.d_val; 1177 break; 1178 1179 case DT_MIPS_GOTSYM: 1180 obj->gotsym = dynp->d_un.d_val; 1181 break; 1182 1183 case DT_MIPS_RLD_MAP: 1184 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1185 break; 1186 #endif 1187 1188 #ifdef __powerpc64__ 1189 case DT_PPC64_GLINK: 1190 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1191 break; 1192 #endif 1193 1194 case DT_FLAGS_1: 1195 if (dynp->d_un.d_val & DF_1_NOOPEN) 1196 obj->z_noopen = true; 1197 if (dynp->d_un.d_val & DF_1_ORIGIN) 1198 obj->z_origin = true; 1199 if (dynp->d_un.d_val & DF_1_GLOBAL) 1200 obj->z_global = true; 1201 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1202 obj->bind_now = true; 1203 if (dynp->d_un.d_val & DF_1_NODELETE) 1204 obj->z_nodelete = true; 1205 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1206 obj->z_loadfltr = true; 1207 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1208 obj->z_interpose = true; 1209 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1210 obj->z_nodeflib = true; 1211 break; 1212 1213 default: 1214 if (!early) { 1215 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1216 (long)dynp->d_tag); 1217 } 1218 break; 1219 } 1220 } 1221 1222 obj->traced = false; 1223 1224 if (plttype == DT_RELA) { 1225 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1226 obj->pltrel = NULL; 1227 obj->pltrelasize = obj->pltrelsize; 1228 obj->pltrelsize = 0; 1229 } 1230 1231 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1232 if (obj->valid_hash_sysv) 1233 obj->dynsymcount = obj->nchains; 1234 else if (obj->valid_hash_gnu) { 1235 obj->dynsymcount = 0; 1236 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1237 if (obj->buckets_gnu[bkt] == 0) 1238 continue; 1239 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1240 do 1241 obj->dynsymcount++; 1242 while ((*hashval++ & 1u) == 0); 1243 } 1244 obj->dynsymcount += obj->symndx_gnu; 1245 } 1246 } 1247 1248 static bool 1249 obj_resolve_origin(Obj_Entry *obj) 1250 { 1251 1252 if (obj->origin_path != NULL) 1253 return (true); 1254 obj->origin_path = xmalloc(PATH_MAX); 1255 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1256 } 1257 1258 static void 1259 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1260 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1261 { 1262 1263 if (obj->z_origin && !obj_resolve_origin(obj)) 1264 rtld_die(); 1265 1266 if (dyn_runpath != NULL) { 1267 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1268 obj->runpath = origin_subst(obj, obj->runpath); 1269 } else if (dyn_rpath != NULL) { 1270 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1271 obj->rpath = origin_subst(obj, obj->rpath); 1272 } 1273 if (dyn_soname != NULL) 1274 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1275 } 1276 1277 static void 1278 digest_dynamic(Obj_Entry *obj, int early) 1279 { 1280 const Elf_Dyn *dyn_rpath; 1281 const Elf_Dyn *dyn_soname; 1282 const Elf_Dyn *dyn_runpath; 1283 1284 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1285 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1286 } 1287 1288 /* 1289 * Process a shared object's program header. This is used only for the 1290 * main program, when the kernel has already loaded the main program 1291 * into memory before calling the dynamic linker. It creates and 1292 * returns an Obj_Entry structure. 1293 */ 1294 static Obj_Entry * 1295 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1296 { 1297 Obj_Entry *obj; 1298 const Elf_Phdr *phlimit = phdr + phnum; 1299 const Elf_Phdr *ph; 1300 Elf_Addr note_start, note_end; 1301 int nsegs = 0; 1302 1303 obj = obj_new(); 1304 for (ph = phdr; ph < phlimit; ph++) { 1305 if (ph->p_type != PT_PHDR) 1306 continue; 1307 1308 obj->phdr = phdr; 1309 obj->phsize = ph->p_memsz; 1310 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1311 break; 1312 } 1313 1314 obj->stack_flags = PF_X | PF_R | PF_W; 1315 1316 for (ph = phdr; ph < phlimit; ph++) { 1317 switch (ph->p_type) { 1318 1319 case PT_INTERP: 1320 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1321 break; 1322 1323 case PT_LOAD: 1324 if (nsegs == 0) { /* First load segment */ 1325 obj->vaddrbase = trunc_page(ph->p_vaddr); 1326 obj->mapbase = obj->vaddrbase + obj->relocbase; 1327 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1328 obj->vaddrbase; 1329 } else { /* Last load segment */ 1330 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1331 obj->vaddrbase; 1332 } 1333 nsegs++; 1334 break; 1335 1336 case PT_DYNAMIC: 1337 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1338 break; 1339 1340 case PT_TLS: 1341 obj->tlsindex = 1; 1342 obj->tlssize = ph->p_memsz; 1343 obj->tlsalign = ph->p_align; 1344 obj->tlsinitsize = ph->p_filesz; 1345 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1346 break; 1347 1348 case PT_GNU_STACK: 1349 obj->stack_flags = ph->p_flags; 1350 break; 1351 1352 case PT_GNU_RELRO: 1353 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1354 obj->relro_size = round_page(ph->p_memsz); 1355 break; 1356 1357 case PT_NOTE: 1358 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1359 note_end = note_start + ph->p_filesz; 1360 digest_notes(obj, note_start, note_end); 1361 break; 1362 } 1363 } 1364 if (nsegs < 1) { 1365 _rtld_error("%s: too few PT_LOAD segments", path); 1366 return NULL; 1367 } 1368 1369 obj->entry = entry; 1370 return obj; 1371 } 1372 1373 void 1374 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1375 { 1376 const Elf_Note *note; 1377 const char *note_name; 1378 uintptr_t p; 1379 1380 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1381 note = (const Elf_Note *)((const char *)(note + 1) + 1382 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1383 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1384 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1385 note->n_descsz != sizeof(int32_t)) 1386 continue; 1387 if (note->n_type != NT_FREEBSD_ABI_TAG && 1388 note->n_type != NT_FREEBSD_NOINIT_TAG) 1389 continue; 1390 note_name = (const char *)(note + 1); 1391 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1392 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1393 continue; 1394 switch (note->n_type) { 1395 case NT_FREEBSD_ABI_TAG: 1396 /* FreeBSD osrel note */ 1397 p = (uintptr_t)(note + 1); 1398 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1399 obj->osrel = *(const int32_t *)(p); 1400 dbg("note osrel %d", obj->osrel); 1401 break; 1402 case NT_FREEBSD_NOINIT_TAG: 1403 /* FreeBSD 'crt does not call init' note */ 1404 obj->crt_no_init = true; 1405 dbg("note crt_no_init"); 1406 break; 1407 } 1408 } 1409 } 1410 1411 static Obj_Entry * 1412 dlcheck(void *handle) 1413 { 1414 Obj_Entry *obj; 1415 1416 TAILQ_FOREACH(obj, &obj_list, next) { 1417 if (obj == (Obj_Entry *) handle) 1418 break; 1419 } 1420 1421 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1422 _rtld_error("Invalid shared object handle %p", handle); 1423 return NULL; 1424 } 1425 return obj; 1426 } 1427 1428 /* 1429 * If the given object is already in the donelist, return true. Otherwise 1430 * add the object to the list and return false. 1431 */ 1432 static bool 1433 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1434 { 1435 unsigned int i; 1436 1437 for (i = 0; i < dlp->num_used; i++) 1438 if (dlp->objs[i] == obj) 1439 return true; 1440 /* 1441 * Our donelist allocation should always be sufficient. But if 1442 * our threads locking isn't working properly, more shared objects 1443 * could have been loaded since we allocated the list. That should 1444 * never happen, but we'll handle it properly just in case it does. 1445 */ 1446 if (dlp->num_used < dlp->num_alloc) 1447 dlp->objs[dlp->num_used++] = obj; 1448 return false; 1449 } 1450 1451 /* 1452 * Hash function for symbol table lookup. Don't even think about changing 1453 * this. It is specified by the System V ABI. 1454 */ 1455 unsigned long 1456 elf_hash(const char *name) 1457 { 1458 const unsigned char *p = (const unsigned char *) name; 1459 unsigned long h = 0; 1460 unsigned long g; 1461 1462 while (*p != '\0') { 1463 h = (h << 4) + *p++; 1464 if ((g = h & 0xf0000000) != 0) 1465 h ^= g >> 24; 1466 h &= ~g; 1467 } 1468 return h; 1469 } 1470 1471 /* 1472 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1473 * unsigned in case it's implemented with a wider type. 1474 */ 1475 static uint32_t 1476 gnu_hash(const char *s) 1477 { 1478 uint32_t h; 1479 unsigned char c; 1480 1481 h = 5381; 1482 for (c = *s; c != '\0'; c = *++s) 1483 h = h * 33 + c; 1484 return (h & 0xffffffff); 1485 } 1486 1487 1488 /* 1489 * Find the library with the given name, and return its full pathname. 1490 * The returned string is dynamically allocated. Generates an error 1491 * message and returns NULL if the library cannot be found. 1492 * 1493 * If the second argument is non-NULL, then it refers to an already- 1494 * loaded shared object, whose library search path will be searched. 1495 * 1496 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1497 * descriptor (which is close-on-exec) will be passed out via the third 1498 * argument. 1499 * 1500 * The search order is: 1501 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1502 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1503 * LD_LIBRARY_PATH 1504 * DT_RUNPATH in the referencing file 1505 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1506 * from list) 1507 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1508 * 1509 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1510 */ 1511 static char * 1512 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1513 { 1514 char *pathname; 1515 char *name; 1516 bool nodeflib, objgiven; 1517 1518 objgiven = refobj != NULL; 1519 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1520 if (xname[0] != '/' && !trust) { 1521 _rtld_error("Absolute pathname required for shared object \"%s\"", 1522 xname); 1523 return NULL; 1524 } 1525 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1526 __DECONST(char *, xname))); 1527 } 1528 1529 if (libmap_disable || !objgiven || 1530 (name = lm_find(refobj->path, xname)) == NULL) 1531 name = (char *)xname; 1532 1533 dbg(" Searching for \"%s\"", name); 1534 1535 /* 1536 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1537 * back to pre-conforming behaviour if user requested so with 1538 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1539 * nodeflib. 1540 */ 1541 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1542 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1543 (refobj != NULL && 1544 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1545 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1546 (pathname = search_library_path(name, gethints(false))) != NULL || 1547 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1548 return (pathname); 1549 } else { 1550 nodeflib = objgiven ? refobj->z_nodeflib : false; 1551 if ((objgiven && 1552 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1553 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1554 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1555 (pathname = search_library_path(name, ld_library_path)) != NULL || 1556 (objgiven && 1557 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1558 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1559 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1560 (objgiven && !nodeflib && 1561 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1562 return (pathname); 1563 } 1564 1565 if (objgiven && refobj->path != NULL) { 1566 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1567 name, basename(refobj->path)); 1568 } else { 1569 _rtld_error("Shared object \"%s\" not found", name); 1570 } 1571 return NULL; 1572 } 1573 1574 /* 1575 * Given a symbol number in a referencing object, find the corresponding 1576 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1577 * no definition was found. Returns a pointer to the Obj_Entry of the 1578 * defining object via the reference parameter DEFOBJ_OUT. 1579 */ 1580 const Elf_Sym * 1581 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1582 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1583 RtldLockState *lockstate) 1584 { 1585 const Elf_Sym *ref; 1586 const Elf_Sym *def; 1587 const Obj_Entry *defobj; 1588 SymLook req; 1589 const char *name; 1590 int res; 1591 1592 /* 1593 * If we have already found this symbol, get the information from 1594 * the cache. 1595 */ 1596 if (symnum >= refobj->dynsymcount) 1597 return NULL; /* Bad object */ 1598 if (cache != NULL && cache[symnum].sym != NULL) { 1599 *defobj_out = cache[symnum].obj; 1600 return cache[symnum].sym; 1601 } 1602 1603 ref = refobj->symtab + symnum; 1604 name = refobj->strtab + ref->st_name; 1605 def = NULL; 1606 defobj = NULL; 1607 1608 /* 1609 * We don't have to do a full scale lookup if the symbol is local. 1610 * We know it will bind to the instance in this load module; to 1611 * which we already have a pointer (ie ref). By not doing a lookup, 1612 * we not only improve performance, but it also avoids unresolvable 1613 * symbols when local symbols are not in the hash table. This has 1614 * been seen with the ia64 toolchain. 1615 */ 1616 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1617 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1618 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1619 symnum); 1620 } 1621 symlook_init(&req, name); 1622 req.flags = flags; 1623 req.ventry = fetch_ventry(refobj, symnum); 1624 req.lockstate = lockstate; 1625 res = symlook_default(&req, refobj); 1626 if (res == 0) { 1627 def = req.sym_out; 1628 defobj = req.defobj_out; 1629 } 1630 } else { 1631 def = ref; 1632 defobj = refobj; 1633 } 1634 1635 /* 1636 * If we found no definition and the reference is weak, treat the 1637 * symbol as having the value zero. 1638 */ 1639 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1640 def = &sym_zero; 1641 defobj = obj_main; 1642 } 1643 1644 if (def != NULL) { 1645 *defobj_out = defobj; 1646 /* Record the information in the cache to avoid subsequent lookups. */ 1647 if (cache != NULL) { 1648 cache[symnum].sym = def; 1649 cache[symnum].obj = defobj; 1650 } 1651 } else { 1652 if (refobj != &obj_rtld) 1653 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1654 } 1655 return def; 1656 } 1657 1658 /* 1659 * Return the search path from the ldconfig hints file, reading it if 1660 * necessary. If nostdlib is true, then the default search paths are 1661 * not added to result. 1662 * 1663 * Returns NULL if there are problems with the hints file, 1664 * or if the search path there is empty. 1665 */ 1666 static const char * 1667 gethints(bool nostdlib) 1668 { 1669 static char *hints, *filtered_path; 1670 static struct elfhints_hdr hdr; 1671 struct fill_search_info_args sargs, hargs; 1672 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1673 struct dl_serpath *SLPpath, *hintpath; 1674 char *p; 1675 struct stat hint_stat; 1676 unsigned int SLPndx, hintndx, fndx, fcount; 1677 int fd; 1678 size_t flen; 1679 uint32_t dl; 1680 bool skip; 1681 1682 /* First call, read the hints file */ 1683 if (hints == NULL) { 1684 /* Keep from trying again in case the hints file is bad. */ 1685 hints = ""; 1686 1687 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1688 return (NULL); 1689 1690 /* 1691 * Check of hdr.dirlistlen value against type limit 1692 * intends to pacify static analyzers. Further 1693 * paranoia leads to checks that dirlist is fully 1694 * contained in the file range. 1695 */ 1696 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1697 hdr.magic != ELFHINTS_MAGIC || 1698 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1699 fstat(fd, &hint_stat) == -1) { 1700 cleanup1: 1701 close(fd); 1702 hdr.dirlistlen = 0; 1703 return (NULL); 1704 } 1705 dl = hdr.strtab; 1706 if (dl + hdr.dirlist < dl) 1707 goto cleanup1; 1708 dl += hdr.dirlist; 1709 if (dl + hdr.dirlistlen < dl) 1710 goto cleanup1; 1711 dl += hdr.dirlistlen; 1712 if (dl > hint_stat.st_size) 1713 goto cleanup1; 1714 p = xmalloc(hdr.dirlistlen + 1); 1715 1716 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1717 read(fd, p, hdr.dirlistlen + 1) != 1718 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1719 free(p); 1720 goto cleanup1; 1721 } 1722 hints = p; 1723 close(fd); 1724 } 1725 1726 /* 1727 * If caller agreed to receive list which includes the default 1728 * paths, we are done. Otherwise, if we still did not 1729 * calculated filtered result, do it now. 1730 */ 1731 if (!nostdlib) 1732 return (hints[0] != '\0' ? hints : NULL); 1733 if (filtered_path != NULL) 1734 goto filt_ret; 1735 1736 /* 1737 * Obtain the list of all configured search paths, and the 1738 * list of the default paths. 1739 * 1740 * First estimate the size of the results. 1741 */ 1742 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1743 smeta.dls_cnt = 0; 1744 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1745 hmeta.dls_cnt = 0; 1746 1747 sargs.request = RTLD_DI_SERINFOSIZE; 1748 sargs.serinfo = &smeta; 1749 hargs.request = RTLD_DI_SERINFOSIZE; 1750 hargs.serinfo = &hmeta; 1751 1752 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1753 path_enumerate(hints, fill_search_info, &hargs); 1754 1755 SLPinfo = xmalloc(smeta.dls_size); 1756 hintinfo = xmalloc(hmeta.dls_size); 1757 1758 /* 1759 * Next fetch both sets of paths. 1760 */ 1761 sargs.request = RTLD_DI_SERINFO; 1762 sargs.serinfo = SLPinfo; 1763 sargs.serpath = &SLPinfo->dls_serpath[0]; 1764 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1765 1766 hargs.request = RTLD_DI_SERINFO; 1767 hargs.serinfo = hintinfo; 1768 hargs.serpath = &hintinfo->dls_serpath[0]; 1769 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1770 1771 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1772 path_enumerate(hints, fill_search_info, &hargs); 1773 1774 /* 1775 * Now calculate the difference between two sets, by excluding 1776 * standard paths from the full set. 1777 */ 1778 fndx = 0; 1779 fcount = 0; 1780 filtered_path = xmalloc(hdr.dirlistlen + 1); 1781 hintpath = &hintinfo->dls_serpath[0]; 1782 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1783 skip = false; 1784 SLPpath = &SLPinfo->dls_serpath[0]; 1785 /* 1786 * Check each standard path against current. 1787 */ 1788 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1789 /* matched, skip the path */ 1790 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1791 skip = true; 1792 break; 1793 } 1794 } 1795 if (skip) 1796 continue; 1797 /* 1798 * Not matched against any standard path, add the path 1799 * to result. Separate consequtive paths with ':'. 1800 */ 1801 if (fcount > 0) { 1802 filtered_path[fndx] = ':'; 1803 fndx++; 1804 } 1805 fcount++; 1806 flen = strlen(hintpath->dls_name); 1807 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1808 fndx += flen; 1809 } 1810 filtered_path[fndx] = '\0'; 1811 1812 free(SLPinfo); 1813 free(hintinfo); 1814 1815 filt_ret: 1816 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1817 } 1818 1819 static void 1820 init_dag(Obj_Entry *root) 1821 { 1822 const Needed_Entry *needed; 1823 const Objlist_Entry *elm; 1824 DoneList donelist; 1825 1826 if (root->dag_inited) 1827 return; 1828 donelist_init(&donelist); 1829 1830 /* Root object belongs to own DAG. */ 1831 objlist_push_tail(&root->dldags, root); 1832 objlist_push_tail(&root->dagmembers, root); 1833 donelist_check(&donelist, root); 1834 1835 /* 1836 * Add dependencies of root object to DAG in breadth order 1837 * by exploiting the fact that each new object get added 1838 * to the tail of the dagmembers list. 1839 */ 1840 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1841 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1842 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1843 continue; 1844 objlist_push_tail(&needed->obj->dldags, root); 1845 objlist_push_tail(&root->dagmembers, needed->obj); 1846 } 1847 } 1848 root->dag_inited = true; 1849 } 1850 1851 Obj_Entry * 1852 globallist_curr(const Obj_Entry *obj) 1853 { 1854 1855 for (;;) { 1856 if (obj == NULL) 1857 return (NULL); 1858 if (!obj->marker) 1859 return (__DECONST(Obj_Entry *, obj)); 1860 obj = TAILQ_PREV(obj, obj_entry_q, next); 1861 } 1862 } 1863 1864 Obj_Entry * 1865 globallist_next(const Obj_Entry *obj) 1866 { 1867 1868 for (;;) { 1869 obj = TAILQ_NEXT(obj, next); 1870 if (obj == NULL) 1871 return (NULL); 1872 if (!obj->marker) 1873 return (__DECONST(Obj_Entry *, obj)); 1874 } 1875 } 1876 1877 static void 1878 process_z(Obj_Entry *root) 1879 { 1880 const Objlist_Entry *elm; 1881 Obj_Entry *obj; 1882 1883 /* 1884 * Walk over object DAG and process every dependent object 1885 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1886 * to grow their own DAG. 1887 * 1888 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1889 * symlook_global() to work. 1890 * 1891 * For DF_1_NODELETE, the DAG should have its reference upped. 1892 */ 1893 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1894 obj = elm->obj; 1895 if (obj == NULL) 1896 continue; 1897 if (obj->z_nodelete && !obj->ref_nodel) { 1898 dbg("obj %s -z nodelete", obj->path); 1899 init_dag(obj); 1900 ref_dag(obj); 1901 obj->ref_nodel = true; 1902 } 1903 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1904 dbg("obj %s -z global", obj->path); 1905 objlist_push_tail(&list_global, obj); 1906 init_dag(obj); 1907 } 1908 } 1909 } 1910 /* 1911 * Initialize the dynamic linker. The argument is the address at which 1912 * the dynamic linker has been mapped into memory. The primary task of 1913 * this function is to relocate the dynamic linker. 1914 */ 1915 static void 1916 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1917 { 1918 Obj_Entry objtmp; /* Temporary rtld object */ 1919 const Elf_Dyn *dyn_rpath; 1920 const Elf_Dyn *dyn_soname; 1921 const Elf_Dyn *dyn_runpath; 1922 1923 #ifdef RTLD_INIT_PAGESIZES_EARLY 1924 /* The page size is required by the dynamic memory allocator. */ 1925 init_pagesizes(aux_info); 1926 #endif 1927 1928 /* 1929 * Conjure up an Obj_Entry structure for the dynamic linker. 1930 * 1931 * The "path" member can't be initialized yet because string constants 1932 * cannot yet be accessed. Below we will set it correctly. 1933 */ 1934 memset(&objtmp, 0, sizeof(objtmp)); 1935 objtmp.path = NULL; 1936 objtmp.rtld = true; 1937 objtmp.mapbase = mapbase; 1938 #ifdef PIC 1939 objtmp.relocbase = mapbase; 1940 #endif 1941 if (RTLD_IS_DYNAMIC()) { 1942 objtmp.dynamic = rtld_dynamic(&objtmp); 1943 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1944 assert(objtmp.needed == NULL); 1945 #if !defined(__mips__) 1946 /* MIPS has a bogus DT_TEXTREL. */ 1947 assert(!objtmp.textrel); 1948 #endif 1949 1950 /* 1951 * Temporarily put the dynamic linker entry into the object list, so 1952 * that symbols can be found. 1953 */ 1954 1955 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1956 } 1957 1958 /* Initialize the object list. */ 1959 TAILQ_INIT(&obj_list); 1960 1961 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1962 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1963 1964 #ifndef RTLD_INIT_PAGESIZES_EARLY 1965 /* The page size is required by the dynamic memory allocator. */ 1966 init_pagesizes(aux_info); 1967 #endif 1968 1969 if (aux_info[AT_OSRELDATE] != NULL) 1970 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1971 1972 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1973 1974 /* Replace the path with a dynamically allocated copy. */ 1975 obj_rtld.path = xstrdup(ld_path_rtld); 1976 1977 r_debug.r_brk = r_debug_state; 1978 r_debug.r_state = RT_CONSISTENT; 1979 } 1980 1981 /* 1982 * Retrieve the array of supported page sizes. The kernel provides the page 1983 * sizes in increasing order. 1984 */ 1985 static void 1986 init_pagesizes(Elf_Auxinfo **aux_info) 1987 { 1988 static size_t psa[MAXPAGESIZES]; 1989 int mib[2]; 1990 size_t len, size; 1991 1992 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1993 NULL) { 1994 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1995 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1996 } else { 1997 len = 2; 1998 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1999 size = sizeof(psa); 2000 else { 2001 /* As a fallback, retrieve the base page size. */ 2002 size = sizeof(psa[0]); 2003 if (aux_info[AT_PAGESZ] != NULL) { 2004 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2005 goto psa_filled; 2006 } else { 2007 mib[0] = CTL_HW; 2008 mib[1] = HW_PAGESIZE; 2009 len = 2; 2010 } 2011 } 2012 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2013 _rtld_error("sysctl for hw.pagesize(s) failed"); 2014 rtld_die(); 2015 } 2016 psa_filled: 2017 pagesizes = psa; 2018 } 2019 npagesizes = size / sizeof(pagesizes[0]); 2020 /* Discard any invalid entries at the end of the array. */ 2021 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2022 npagesizes--; 2023 } 2024 2025 /* 2026 * Add the init functions from a needed object list (and its recursive 2027 * needed objects) to "list". This is not used directly; it is a helper 2028 * function for initlist_add_objects(). The write lock must be held 2029 * when this function is called. 2030 */ 2031 static void 2032 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2033 { 2034 /* Recursively process the successor needed objects. */ 2035 if (needed->next != NULL) 2036 initlist_add_neededs(needed->next, list); 2037 2038 /* Process the current needed object. */ 2039 if (needed->obj != NULL) 2040 initlist_add_objects(needed->obj, needed->obj, list); 2041 } 2042 2043 /* 2044 * Scan all of the DAGs rooted in the range of objects from "obj" to 2045 * "tail" and add their init functions to "list". This recurses over 2046 * the DAGs and ensure the proper init ordering such that each object's 2047 * needed libraries are initialized before the object itself. At the 2048 * same time, this function adds the objects to the global finalization 2049 * list "list_fini" in the opposite order. The write lock must be 2050 * held when this function is called. 2051 */ 2052 static void 2053 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2054 { 2055 Obj_Entry *nobj; 2056 2057 if (obj->init_scanned || obj->init_done) 2058 return; 2059 obj->init_scanned = true; 2060 2061 /* Recursively process the successor objects. */ 2062 nobj = globallist_next(obj); 2063 if (nobj != NULL && obj != tail) 2064 initlist_add_objects(nobj, tail, list); 2065 2066 /* Recursively process the needed objects. */ 2067 if (obj->needed != NULL) 2068 initlist_add_neededs(obj->needed, list); 2069 if (obj->needed_filtees != NULL) 2070 initlist_add_neededs(obj->needed_filtees, list); 2071 if (obj->needed_aux_filtees != NULL) 2072 initlist_add_neededs(obj->needed_aux_filtees, list); 2073 2074 /* Add the object to the init list. */ 2075 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2076 obj->init_array != (Elf_Addr)NULL) 2077 objlist_push_tail(list, obj); 2078 2079 /* Add the object to the global fini list in the reverse order. */ 2080 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2081 && !obj->on_fini_list) { 2082 objlist_push_head(&list_fini, obj); 2083 obj->on_fini_list = true; 2084 } 2085 } 2086 2087 #ifndef FPTR_TARGET 2088 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2089 #endif 2090 2091 static void 2092 free_needed_filtees(Needed_Entry *n) 2093 { 2094 Needed_Entry *needed, *needed1; 2095 2096 for (needed = n; needed != NULL; needed = needed->next) { 2097 if (needed->obj != NULL) { 2098 dlclose(needed->obj); 2099 needed->obj = NULL; 2100 } 2101 } 2102 for (needed = n; needed != NULL; needed = needed1) { 2103 needed1 = needed->next; 2104 free(needed); 2105 } 2106 } 2107 2108 static void 2109 unload_filtees(Obj_Entry *obj) 2110 { 2111 2112 free_needed_filtees(obj->needed_filtees); 2113 obj->needed_filtees = NULL; 2114 free_needed_filtees(obj->needed_aux_filtees); 2115 obj->needed_aux_filtees = NULL; 2116 obj->filtees_loaded = false; 2117 } 2118 2119 static void 2120 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2121 RtldLockState *lockstate) 2122 { 2123 2124 for (; needed != NULL; needed = needed->next) { 2125 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2126 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2127 RTLD_LOCAL, lockstate); 2128 } 2129 } 2130 2131 static void 2132 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2133 { 2134 2135 lock_restart_for_upgrade(lockstate); 2136 if (!obj->filtees_loaded) { 2137 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2138 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2139 obj->filtees_loaded = true; 2140 } 2141 } 2142 2143 static int 2144 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2145 { 2146 Obj_Entry *obj1; 2147 2148 for (; needed != NULL; needed = needed->next) { 2149 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2150 flags & ~RTLD_LO_NOLOAD); 2151 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2152 return (-1); 2153 } 2154 return (0); 2155 } 2156 2157 /* 2158 * Given a shared object, traverse its list of needed objects, and load 2159 * each of them. Returns 0 on success. Generates an error message and 2160 * returns -1 on failure. 2161 */ 2162 static int 2163 load_needed_objects(Obj_Entry *first, int flags) 2164 { 2165 Obj_Entry *obj; 2166 2167 obj = first; 2168 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2169 if (obj->marker) 2170 continue; 2171 if (process_needed(obj, obj->needed, flags) == -1) 2172 return (-1); 2173 } 2174 return (0); 2175 } 2176 2177 static int 2178 load_preload_objects(void) 2179 { 2180 char *p = ld_preload; 2181 Obj_Entry *obj; 2182 static const char delim[] = " \t:;"; 2183 2184 if (p == NULL) 2185 return 0; 2186 2187 p += strspn(p, delim); 2188 while (*p != '\0') { 2189 size_t len = strcspn(p, delim); 2190 char savech; 2191 2192 savech = p[len]; 2193 p[len] = '\0'; 2194 obj = load_object(p, -1, NULL, 0); 2195 if (obj == NULL) 2196 return -1; /* XXX - cleanup */ 2197 obj->z_interpose = true; 2198 p[len] = savech; 2199 p += len; 2200 p += strspn(p, delim); 2201 } 2202 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2203 return 0; 2204 } 2205 2206 static const char * 2207 printable_path(const char *path) 2208 { 2209 2210 return (path == NULL ? "<unknown>" : path); 2211 } 2212 2213 /* 2214 * Load a shared object into memory, if it is not already loaded. The 2215 * object may be specified by name or by user-supplied file descriptor 2216 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2217 * duplicate is. 2218 * 2219 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2220 * on failure. 2221 */ 2222 static Obj_Entry * 2223 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2224 { 2225 Obj_Entry *obj; 2226 int fd; 2227 struct stat sb; 2228 char *path; 2229 2230 fd = -1; 2231 if (name != NULL) { 2232 TAILQ_FOREACH(obj, &obj_list, next) { 2233 if (obj->marker) 2234 continue; 2235 if (object_match_name(obj, name)) 2236 return (obj); 2237 } 2238 2239 path = find_library(name, refobj, &fd); 2240 if (path == NULL) 2241 return (NULL); 2242 } else 2243 path = NULL; 2244 2245 if (fd >= 0) { 2246 /* 2247 * search_library_pathfds() opens a fresh file descriptor for the 2248 * library, so there is no need to dup(). 2249 */ 2250 } else if (fd_u == -1) { 2251 /* 2252 * If we didn't find a match by pathname, or the name is not 2253 * supplied, open the file and check again by device and inode. 2254 * This avoids false mismatches caused by multiple links or ".." 2255 * in pathnames. 2256 * 2257 * To avoid a race, we open the file and use fstat() rather than 2258 * using stat(). 2259 */ 2260 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2261 _rtld_error("Cannot open \"%s\"", path); 2262 free(path); 2263 return (NULL); 2264 } 2265 } else { 2266 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2267 if (fd == -1) { 2268 _rtld_error("Cannot dup fd"); 2269 free(path); 2270 return (NULL); 2271 } 2272 } 2273 if (fstat(fd, &sb) == -1) { 2274 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2275 close(fd); 2276 free(path); 2277 return NULL; 2278 } 2279 TAILQ_FOREACH(obj, &obj_list, next) { 2280 if (obj->marker) 2281 continue; 2282 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2283 break; 2284 } 2285 if (obj != NULL && name != NULL) { 2286 object_add_name(obj, name); 2287 free(path); 2288 close(fd); 2289 return obj; 2290 } 2291 if (flags & RTLD_LO_NOLOAD) { 2292 free(path); 2293 close(fd); 2294 return (NULL); 2295 } 2296 2297 /* First use of this object, so we must map it in */ 2298 obj = do_load_object(fd, name, path, &sb, flags); 2299 if (obj == NULL) 2300 free(path); 2301 close(fd); 2302 2303 return obj; 2304 } 2305 2306 static Obj_Entry * 2307 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2308 int flags) 2309 { 2310 Obj_Entry *obj; 2311 struct statfs fs; 2312 2313 /* 2314 * but first, make sure that environment variables haven't been 2315 * used to circumvent the noexec flag on a filesystem. 2316 */ 2317 if (dangerous_ld_env) { 2318 if (fstatfs(fd, &fs) != 0) { 2319 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2320 return NULL; 2321 } 2322 if (fs.f_flags & MNT_NOEXEC) { 2323 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2324 return NULL; 2325 } 2326 } 2327 dbg("loading \"%s\"", printable_path(path)); 2328 obj = map_object(fd, printable_path(path), sbp); 2329 if (obj == NULL) 2330 return NULL; 2331 2332 /* 2333 * If DT_SONAME is present in the object, digest_dynamic2 already 2334 * added it to the object names. 2335 */ 2336 if (name != NULL) 2337 object_add_name(obj, name); 2338 obj->path = path; 2339 digest_dynamic(obj, 0); 2340 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2341 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2342 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2343 RTLD_LO_DLOPEN) { 2344 dbg("refusing to load non-loadable \"%s\"", obj->path); 2345 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2346 munmap(obj->mapbase, obj->mapsize); 2347 obj_free(obj); 2348 return (NULL); 2349 } 2350 2351 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2352 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2353 obj_count++; 2354 obj_loads++; 2355 linkmap_add(obj); /* for GDB & dlinfo() */ 2356 max_stack_flags |= obj->stack_flags; 2357 2358 dbg(" %p .. %p: %s", obj->mapbase, 2359 obj->mapbase + obj->mapsize - 1, obj->path); 2360 if (obj->textrel) 2361 dbg(" WARNING: %s has impure text", obj->path); 2362 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2363 obj->path); 2364 2365 return obj; 2366 } 2367 2368 static Obj_Entry * 2369 obj_from_addr(const void *addr) 2370 { 2371 Obj_Entry *obj; 2372 2373 TAILQ_FOREACH(obj, &obj_list, next) { 2374 if (obj->marker) 2375 continue; 2376 if (addr < (void *) obj->mapbase) 2377 continue; 2378 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2379 return obj; 2380 } 2381 return NULL; 2382 } 2383 2384 static void 2385 preinit_main(void) 2386 { 2387 Elf_Addr *preinit_addr; 2388 int index; 2389 2390 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2391 if (preinit_addr == NULL) 2392 return; 2393 2394 for (index = 0; index < obj_main->preinit_array_num; index++) { 2395 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2396 dbg("calling preinit function for %s at %p", obj_main->path, 2397 (void *)preinit_addr[index]); 2398 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2399 0, 0, obj_main->path); 2400 call_init_pointer(obj_main, preinit_addr[index]); 2401 } 2402 } 2403 } 2404 2405 /* 2406 * Call the finalization functions for each of the objects in "list" 2407 * belonging to the DAG of "root" and referenced once. If NULL "root" 2408 * is specified, every finalization function will be called regardless 2409 * of the reference count and the list elements won't be freed. All of 2410 * the objects are expected to have non-NULL fini functions. 2411 */ 2412 static void 2413 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2414 { 2415 Objlist_Entry *elm; 2416 char *saved_msg; 2417 Elf_Addr *fini_addr; 2418 int index; 2419 2420 assert(root == NULL || root->refcount == 1); 2421 2422 /* 2423 * Preserve the current error message since a fini function might 2424 * call into the dynamic linker and overwrite it. 2425 */ 2426 saved_msg = errmsg_save(); 2427 do { 2428 STAILQ_FOREACH(elm, list, link) { 2429 if (root != NULL && (elm->obj->refcount != 1 || 2430 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2431 continue; 2432 /* Remove object from fini list to prevent recursive invocation. */ 2433 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2434 /* 2435 * XXX: If a dlopen() call references an object while the 2436 * fini function is in progress, we might end up trying to 2437 * unload the referenced object in dlclose() or the object 2438 * won't be unloaded although its fini function has been 2439 * called. 2440 */ 2441 lock_release(rtld_bind_lock, lockstate); 2442 2443 /* 2444 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2445 * When this happens, DT_FINI_ARRAY is processed first. 2446 */ 2447 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2448 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2449 for (index = elm->obj->fini_array_num - 1; index >= 0; 2450 index--) { 2451 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2452 dbg("calling fini function for %s at %p", 2453 elm->obj->path, (void *)fini_addr[index]); 2454 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2455 (void *)fini_addr[index], 0, 0, elm->obj->path); 2456 call_initfini_pointer(elm->obj, fini_addr[index]); 2457 } 2458 } 2459 } 2460 if (elm->obj->fini != (Elf_Addr)NULL) { 2461 dbg("calling fini function for %s at %p", elm->obj->path, 2462 (void *)elm->obj->fini); 2463 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2464 0, 0, elm->obj->path); 2465 call_initfini_pointer(elm->obj, elm->obj->fini); 2466 } 2467 wlock_acquire(rtld_bind_lock, lockstate); 2468 /* No need to free anything if process is going down. */ 2469 if (root != NULL) 2470 free(elm); 2471 /* 2472 * We must restart the list traversal after every fini call 2473 * because a dlclose() call from the fini function or from 2474 * another thread might have modified the reference counts. 2475 */ 2476 break; 2477 } 2478 } while (elm != NULL); 2479 errmsg_restore(saved_msg); 2480 } 2481 2482 /* 2483 * Call the initialization functions for each of the objects in 2484 * "list". All of the objects are expected to have non-NULL init 2485 * functions. 2486 */ 2487 static void 2488 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2489 { 2490 Objlist_Entry *elm; 2491 Obj_Entry *obj; 2492 char *saved_msg; 2493 Elf_Addr *init_addr; 2494 int index; 2495 2496 /* 2497 * Clean init_scanned flag so that objects can be rechecked and 2498 * possibly initialized earlier if any of vectors called below 2499 * cause the change by using dlopen. 2500 */ 2501 TAILQ_FOREACH(obj, &obj_list, next) { 2502 if (obj->marker) 2503 continue; 2504 obj->init_scanned = false; 2505 } 2506 2507 /* 2508 * Preserve the current error message since an init function might 2509 * call into the dynamic linker and overwrite it. 2510 */ 2511 saved_msg = errmsg_save(); 2512 STAILQ_FOREACH(elm, list, link) { 2513 if (elm->obj->init_done) /* Initialized early. */ 2514 continue; 2515 /* 2516 * Race: other thread might try to use this object before current 2517 * one completes the initilization. Not much can be done here 2518 * without better locking. 2519 */ 2520 elm->obj->init_done = true; 2521 lock_release(rtld_bind_lock, lockstate); 2522 2523 /* 2524 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2525 * When this happens, DT_INIT is processed first. 2526 */ 2527 if (elm->obj->init != (Elf_Addr)NULL) { 2528 dbg("calling init function for %s at %p", elm->obj->path, 2529 (void *)elm->obj->init); 2530 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2531 0, 0, elm->obj->path); 2532 call_initfini_pointer(elm->obj, elm->obj->init); 2533 } 2534 init_addr = (Elf_Addr *)elm->obj->init_array; 2535 if (init_addr != NULL) { 2536 for (index = 0; index < elm->obj->init_array_num; index++) { 2537 if (init_addr[index] != 0 && init_addr[index] != 1) { 2538 dbg("calling init function for %s at %p", elm->obj->path, 2539 (void *)init_addr[index]); 2540 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2541 (void *)init_addr[index], 0, 0, elm->obj->path); 2542 call_init_pointer(elm->obj, init_addr[index]); 2543 } 2544 } 2545 } 2546 wlock_acquire(rtld_bind_lock, lockstate); 2547 } 2548 errmsg_restore(saved_msg); 2549 } 2550 2551 static void 2552 objlist_clear(Objlist *list) 2553 { 2554 Objlist_Entry *elm; 2555 2556 while (!STAILQ_EMPTY(list)) { 2557 elm = STAILQ_FIRST(list); 2558 STAILQ_REMOVE_HEAD(list, link); 2559 free(elm); 2560 } 2561 } 2562 2563 static Objlist_Entry * 2564 objlist_find(Objlist *list, const Obj_Entry *obj) 2565 { 2566 Objlist_Entry *elm; 2567 2568 STAILQ_FOREACH(elm, list, link) 2569 if (elm->obj == obj) 2570 return elm; 2571 return NULL; 2572 } 2573 2574 static void 2575 objlist_init(Objlist *list) 2576 { 2577 STAILQ_INIT(list); 2578 } 2579 2580 static void 2581 objlist_push_head(Objlist *list, Obj_Entry *obj) 2582 { 2583 Objlist_Entry *elm; 2584 2585 elm = NEW(Objlist_Entry); 2586 elm->obj = obj; 2587 STAILQ_INSERT_HEAD(list, elm, link); 2588 } 2589 2590 static void 2591 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2592 { 2593 Objlist_Entry *elm; 2594 2595 elm = NEW(Objlist_Entry); 2596 elm->obj = obj; 2597 STAILQ_INSERT_TAIL(list, elm, link); 2598 } 2599 2600 static void 2601 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2602 { 2603 Objlist_Entry *elm, *listelm; 2604 2605 STAILQ_FOREACH(listelm, list, link) { 2606 if (listelm->obj == listobj) 2607 break; 2608 } 2609 elm = NEW(Objlist_Entry); 2610 elm->obj = obj; 2611 if (listelm != NULL) 2612 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2613 else 2614 STAILQ_INSERT_TAIL(list, elm, link); 2615 } 2616 2617 static void 2618 objlist_remove(Objlist *list, Obj_Entry *obj) 2619 { 2620 Objlist_Entry *elm; 2621 2622 if ((elm = objlist_find(list, obj)) != NULL) { 2623 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2624 free(elm); 2625 } 2626 } 2627 2628 /* 2629 * Relocate dag rooted in the specified object. 2630 * Returns 0 on success, or -1 on failure. 2631 */ 2632 2633 static int 2634 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2635 int flags, RtldLockState *lockstate) 2636 { 2637 Objlist_Entry *elm; 2638 int error; 2639 2640 error = 0; 2641 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2642 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2643 lockstate); 2644 if (error == -1) 2645 break; 2646 } 2647 return (error); 2648 } 2649 2650 /* 2651 * Prepare for, or clean after, relocating an object marked with 2652 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2653 * segments are remapped read-write. After relocations are done, the 2654 * segment's permissions are returned back to the modes specified in 2655 * the phdrs. If any relocation happened, or always for wired 2656 * program, COW is triggered. 2657 */ 2658 static int 2659 reloc_textrel_prot(Obj_Entry *obj, bool before) 2660 { 2661 const Elf_Phdr *ph; 2662 void *base; 2663 size_t l, sz; 2664 int prot; 2665 2666 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2667 l--, ph++) { 2668 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2669 continue; 2670 base = obj->relocbase + trunc_page(ph->p_vaddr); 2671 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2672 trunc_page(ph->p_vaddr); 2673 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2674 if (mprotect(base, sz, prot) == -1) { 2675 _rtld_error("%s: Cannot write-%sable text segment: %s", 2676 obj->path, before ? "en" : "dis", 2677 rtld_strerror(errno)); 2678 return (-1); 2679 } 2680 } 2681 return (0); 2682 } 2683 2684 /* 2685 * Relocate single object. 2686 * Returns 0 on success, or -1 on failure. 2687 */ 2688 static int 2689 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2690 int flags, RtldLockState *lockstate) 2691 { 2692 2693 if (obj->relocated) 2694 return (0); 2695 obj->relocated = true; 2696 if (obj != rtldobj) 2697 dbg("relocating \"%s\"", obj->path); 2698 2699 if (obj->symtab == NULL || obj->strtab == NULL || 2700 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2701 _rtld_error("%s: Shared object has no run-time symbol table", 2702 obj->path); 2703 return (-1); 2704 } 2705 2706 /* There are relocations to the write-protected text segment. */ 2707 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2708 return (-1); 2709 2710 /* Process the non-PLT non-IFUNC relocations. */ 2711 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2712 return (-1); 2713 2714 /* Re-protected the text segment. */ 2715 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2716 return (-1); 2717 2718 /* Set the special PLT or GOT entries. */ 2719 init_pltgot(obj); 2720 2721 /* Process the PLT relocations. */ 2722 if (reloc_plt(obj) == -1) 2723 return (-1); 2724 /* Relocate the jump slots if we are doing immediate binding. */ 2725 if (obj->bind_now || bind_now) 2726 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2727 return (-1); 2728 2729 /* 2730 * Process the non-PLT IFUNC relocations. The relocations are 2731 * processed in two phases, because IFUNC resolvers may 2732 * reference other symbols, which must be readily processed 2733 * before resolvers are called. 2734 */ 2735 if (obj->non_plt_gnu_ifunc && 2736 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2737 return (-1); 2738 2739 if (obj->relro_size > 0) { 2740 if (mprotect(obj->relro_page, obj->relro_size, 2741 PROT_READ) == -1) { 2742 _rtld_error("%s: Cannot enforce relro protection: %s", 2743 obj->path, rtld_strerror(errno)); 2744 return (-1); 2745 } 2746 } 2747 2748 /* 2749 * Set up the magic number and version in the Obj_Entry. These 2750 * were checked in the crt1.o from the original ElfKit, so we 2751 * set them for backward compatibility. 2752 */ 2753 obj->magic = RTLD_MAGIC; 2754 obj->version = RTLD_VERSION; 2755 2756 return (0); 2757 } 2758 2759 /* 2760 * Relocate newly-loaded shared objects. The argument is a pointer to 2761 * the Obj_Entry for the first such object. All objects from the first 2762 * to the end of the list of objects are relocated. Returns 0 on success, 2763 * or -1 on failure. 2764 */ 2765 static int 2766 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2767 int flags, RtldLockState *lockstate) 2768 { 2769 Obj_Entry *obj; 2770 int error; 2771 2772 error = 0; 2773 obj = first; 2774 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2775 if (obj->marker) 2776 continue; 2777 error = relocate_object(obj, bind_now, rtldobj, flags, 2778 lockstate); 2779 if (error == -1) 2780 break; 2781 } 2782 return (error); 2783 } 2784 2785 /* 2786 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2787 * referencing STT_GNU_IFUNC symbols is postponed till the other 2788 * relocations are done. The indirect functions specified as 2789 * ifunc are allowed to call other symbols, so we need to have 2790 * objects relocated before asking for resolution from indirects. 2791 * 2792 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2793 * instead of the usual lazy handling of PLT slots. It is 2794 * consistent with how GNU does it. 2795 */ 2796 static int 2797 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2798 RtldLockState *lockstate) 2799 { 2800 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2801 return (-1); 2802 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2803 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2804 return (-1); 2805 return (0); 2806 } 2807 2808 static int 2809 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2810 RtldLockState *lockstate) 2811 { 2812 Obj_Entry *obj; 2813 2814 obj = first; 2815 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2816 if (obj->marker) 2817 continue; 2818 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2819 return (-1); 2820 } 2821 return (0); 2822 } 2823 2824 static int 2825 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2826 RtldLockState *lockstate) 2827 { 2828 Objlist_Entry *elm; 2829 2830 STAILQ_FOREACH(elm, list, link) { 2831 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2832 lockstate) == -1) 2833 return (-1); 2834 } 2835 return (0); 2836 } 2837 2838 /* 2839 * Cleanup procedure. It will be called (by the atexit mechanism) just 2840 * before the process exits. 2841 */ 2842 static void 2843 rtld_exit(void) 2844 { 2845 RtldLockState lockstate; 2846 2847 wlock_acquire(rtld_bind_lock, &lockstate); 2848 dbg("rtld_exit()"); 2849 objlist_call_fini(&list_fini, NULL, &lockstate); 2850 /* No need to remove the items from the list, since we are exiting. */ 2851 if (!libmap_disable) 2852 lm_fini(); 2853 lock_release(rtld_bind_lock, &lockstate); 2854 } 2855 2856 /* 2857 * Iterate over a search path, translate each element, and invoke the 2858 * callback on the result. 2859 */ 2860 static void * 2861 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2862 { 2863 const char *trans; 2864 if (path == NULL) 2865 return (NULL); 2866 2867 path += strspn(path, ":;"); 2868 while (*path != '\0') { 2869 size_t len; 2870 char *res; 2871 2872 len = strcspn(path, ":;"); 2873 trans = lm_findn(NULL, path, len); 2874 if (trans) 2875 res = callback(trans, strlen(trans), arg); 2876 else 2877 res = callback(path, len, arg); 2878 2879 if (res != NULL) 2880 return (res); 2881 2882 path += len; 2883 path += strspn(path, ":;"); 2884 } 2885 2886 return (NULL); 2887 } 2888 2889 struct try_library_args { 2890 const char *name; 2891 size_t namelen; 2892 char *buffer; 2893 size_t buflen; 2894 }; 2895 2896 static void * 2897 try_library_path(const char *dir, size_t dirlen, void *param) 2898 { 2899 struct try_library_args *arg; 2900 2901 arg = param; 2902 if (*dir == '/' || trust) { 2903 char *pathname; 2904 2905 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2906 return (NULL); 2907 2908 pathname = arg->buffer; 2909 strncpy(pathname, dir, dirlen); 2910 pathname[dirlen] = '/'; 2911 strcpy(pathname + dirlen + 1, arg->name); 2912 2913 dbg(" Trying \"%s\"", pathname); 2914 if (access(pathname, F_OK) == 0) { /* We found it */ 2915 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2916 strcpy(pathname, arg->buffer); 2917 return (pathname); 2918 } 2919 } 2920 return (NULL); 2921 } 2922 2923 static char * 2924 search_library_path(const char *name, const char *path) 2925 { 2926 char *p; 2927 struct try_library_args arg; 2928 2929 if (path == NULL) 2930 return NULL; 2931 2932 arg.name = name; 2933 arg.namelen = strlen(name); 2934 arg.buffer = xmalloc(PATH_MAX); 2935 arg.buflen = PATH_MAX; 2936 2937 p = path_enumerate(path, try_library_path, &arg); 2938 2939 free(arg.buffer); 2940 2941 return (p); 2942 } 2943 2944 2945 /* 2946 * Finds the library with the given name using the directory descriptors 2947 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2948 * 2949 * Returns a freshly-opened close-on-exec file descriptor for the library, 2950 * or -1 if the library cannot be found. 2951 */ 2952 static char * 2953 search_library_pathfds(const char *name, const char *path, int *fdp) 2954 { 2955 char *envcopy, *fdstr, *found, *last_token; 2956 size_t len; 2957 int dirfd, fd; 2958 2959 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2960 2961 /* Don't load from user-specified libdirs into setuid binaries. */ 2962 if (!trust) 2963 return (NULL); 2964 2965 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2966 if (path == NULL) 2967 return (NULL); 2968 2969 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2970 if (name[0] == '/') { 2971 dbg("Absolute path (%s) passed to %s", name, __func__); 2972 return (NULL); 2973 } 2974 2975 /* 2976 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2977 * copy of the path, as strtok_r rewrites separator tokens 2978 * with '\0'. 2979 */ 2980 found = NULL; 2981 envcopy = xstrdup(path); 2982 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2983 fdstr = strtok_r(NULL, ":", &last_token)) { 2984 dirfd = parse_libdir(fdstr); 2985 if (dirfd < 0) 2986 break; 2987 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2988 if (fd >= 0) { 2989 *fdp = fd; 2990 len = strlen(fdstr) + strlen(name) + 3; 2991 found = xmalloc(len); 2992 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2993 _rtld_error("error generating '%d/%s'", 2994 dirfd, name); 2995 rtld_die(); 2996 } 2997 dbg("open('%s') => %d", found, fd); 2998 break; 2999 } 3000 } 3001 free(envcopy); 3002 3003 return (found); 3004 } 3005 3006 3007 int 3008 dlclose(void *handle) 3009 { 3010 Obj_Entry *root; 3011 RtldLockState lockstate; 3012 3013 wlock_acquire(rtld_bind_lock, &lockstate); 3014 root = dlcheck(handle); 3015 if (root == NULL) { 3016 lock_release(rtld_bind_lock, &lockstate); 3017 return -1; 3018 } 3019 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3020 root->path); 3021 3022 /* Unreference the object and its dependencies. */ 3023 root->dl_refcount--; 3024 3025 if (root->refcount == 1) { 3026 /* 3027 * The object will be no longer referenced, so we must unload it. 3028 * First, call the fini functions. 3029 */ 3030 objlist_call_fini(&list_fini, root, &lockstate); 3031 3032 unref_dag(root); 3033 3034 /* Finish cleaning up the newly-unreferenced objects. */ 3035 GDB_STATE(RT_DELETE,&root->linkmap); 3036 unload_object(root); 3037 GDB_STATE(RT_CONSISTENT,NULL); 3038 } else 3039 unref_dag(root); 3040 3041 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3042 lock_release(rtld_bind_lock, &lockstate); 3043 return 0; 3044 } 3045 3046 char * 3047 dlerror(void) 3048 { 3049 char *msg = error_message; 3050 error_message = NULL; 3051 return msg; 3052 } 3053 3054 /* 3055 * This function is deprecated and has no effect. 3056 */ 3057 void 3058 dllockinit(void *context, 3059 void *(*lock_create)(void *context), 3060 void (*rlock_acquire)(void *lock), 3061 void (*wlock_acquire)(void *lock), 3062 void (*lock_release)(void *lock), 3063 void (*lock_destroy)(void *lock), 3064 void (*context_destroy)(void *context)) 3065 { 3066 static void *cur_context; 3067 static void (*cur_context_destroy)(void *); 3068 3069 /* Just destroy the context from the previous call, if necessary. */ 3070 if (cur_context_destroy != NULL) 3071 cur_context_destroy(cur_context); 3072 cur_context = context; 3073 cur_context_destroy = context_destroy; 3074 } 3075 3076 void * 3077 dlopen(const char *name, int mode) 3078 { 3079 3080 return (rtld_dlopen(name, -1, mode)); 3081 } 3082 3083 void * 3084 fdlopen(int fd, int mode) 3085 { 3086 3087 return (rtld_dlopen(NULL, fd, mode)); 3088 } 3089 3090 static void * 3091 rtld_dlopen(const char *name, int fd, int mode) 3092 { 3093 RtldLockState lockstate; 3094 int lo_flags; 3095 3096 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3097 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3098 if (ld_tracing != NULL) { 3099 rlock_acquire(rtld_bind_lock, &lockstate); 3100 if (sigsetjmp(lockstate.env, 0) != 0) 3101 lock_upgrade(rtld_bind_lock, &lockstate); 3102 environ = (char **)*get_program_var_addr("environ", &lockstate); 3103 lock_release(rtld_bind_lock, &lockstate); 3104 } 3105 lo_flags = RTLD_LO_DLOPEN; 3106 if (mode & RTLD_NODELETE) 3107 lo_flags |= RTLD_LO_NODELETE; 3108 if (mode & RTLD_NOLOAD) 3109 lo_flags |= RTLD_LO_NOLOAD; 3110 if (ld_tracing != NULL) 3111 lo_flags |= RTLD_LO_TRACE; 3112 3113 return (dlopen_object(name, fd, obj_main, lo_flags, 3114 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3115 } 3116 3117 static void 3118 dlopen_cleanup(Obj_Entry *obj) 3119 { 3120 3121 obj->dl_refcount--; 3122 unref_dag(obj); 3123 if (obj->refcount == 0) 3124 unload_object(obj); 3125 } 3126 3127 static Obj_Entry * 3128 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3129 int mode, RtldLockState *lockstate) 3130 { 3131 Obj_Entry *old_obj_tail; 3132 Obj_Entry *obj; 3133 Objlist initlist; 3134 RtldLockState mlockstate; 3135 int result; 3136 3137 objlist_init(&initlist); 3138 3139 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3140 wlock_acquire(rtld_bind_lock, &mlockstate); 3141 lockstate = &mlockstate; 3142 } 3143 GDB_STATE(RT_ADD,NULL); 3144 3145 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3146 obj = NULL; 3147 if (name == NULL && fd == -1) { 3148 obj = obj_main; 3149 obj->refcount++; 3150 } else { 3151 obj = load_object(name, fd, refobj, lo_flags); 3152 } 3153 3154 if (obj) { 3155 obj->dl_refcount++; 3156 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3157 objlist_push_tail(&list_global, obj); 3158 if (globallist_next(old_obj_tail) != NULL) { 3159 /* We loaded something new. */ 3160 assert(globallist_next(old_obj_tail) == obj); 3161 result = load_needed_objects(obj, 3162 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3163 init_dag(obj); 3164 ref_dag(obj); 3165 if (result != -1) 3166 result = rtld_verify_versions(&obj->dagmembers); 3167 if (result != -1 && ld_tracing) 3168 goto trace; 3169 if (result == -1 || relocate_object_dag(obj, 3170 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3171 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3172 lockstate) == -1) { 3173 dlopen_cleanup(obj); 3174 obj = NULL; 3175 } else if (lo_flags & RTLD_LO_EARLY) { 3176 /* 3177 * Do not call the init functions for early loaded 3178 * filtees. The image is still not initialized enough 3179 * for them to work. 3180 * 3181 * Our object is found by the global object list and 3182 * will be ordered among all init calls done right 3183 * before transferring control to main. 3184 */ 3185 } else { 3186 /* Make list of init functions to call. */ 3187 initlist_add_objects(obj, obj, &initlist); 3188 } 3189 /* 3190 * Process all no_delete or global objects here, given 3191 * them own DAGs to prevent their dependencies from being 3192 * unloaded. This has to be done after we have loaded all 3193 * of the dependencies, so that we do not miss any. 3194 */ 3195 if (obj != NULL) 3196 process_z(obj); 3197 } else { 3198 /* 3199 * Bump the reference counts for objects on this DAG. If 3200 * this is the first dlopen() call for the object that was 3201 * already loaded as a dependency, initialize the dag 3202 * starting at it. 3203 */ 3204 init_dag(obj); 3205 ref_dag(obj); 3206 3207 if ((lo_flags & RTLD_LO_TRACE) != 0) 3208 goto trace; 3209 } 3210 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3211 obj->z_nodelete) && !obj->ref_nodel) { 3212 dbg("obj %s nodelete", obj->path); 3213 ref_dag(obj); 3214 obj->z_nodelete = obj->ref_nodel = true; 3215 } 3216 } 3217 3218 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3219 name); 3220 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3221 3222 if (!(lo_flags & RTLD_LO_EARLY)) { 3223 map_stacks_exec(lockstate); 3224 } 3225 3226 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3227 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3228 lockstate) == -1) { 3229 objlist_clear(&initlist); 3230 dlopen_cleanup(obj); 3231 if (lockstate == &mlockstate) 3232 lock_release(rtld_bind_lock, lockstate); 3233 return (NULL); 3234 } 3235 3236 if (!(lo_flags & RTLD_LO_EARLY)) { 3237 /* Call the init functions. */ 3238 objlist_call_init(&initlist, lockstate); 3239 } 3240 objlist_clear(&initlist); 3241 if (lockstate == &mlockstate) 3242 lock_release(rtld_bind_lock, lockstate); 3243 return obj; 3244 trace: 3245 trace_loaded_objects(obj); 3246 if (lockstate == &mlockstate) 3247 lock_release(rtld_bind_lock, lockstate); 3248 exit(0); 3249 } 3250 3251 static void * 3252 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3253 int flags) 3254 { 3255 DoneList donelist; 3256 const Obj_Entry *obj, *defobj; 3257 const Elf_Sym *def; 3258 SymLook req; 3259 RtldLockState lockstate; 3260 tls_index ti; 3261 void *sym; 3262 int res; 3263 3264 def = NULL; 3265 defobj = NULL; 3266 symlook_init(&req, name); 3267 req.ventry = ve; 3268 req.flags = flags | SYMLOOK_IN_PLT; 3269 req.lockstate = &lockstate; 3270 3271 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3272 rlock_acquire(rtld_bind_lock, &lockstate); 3273 if (sigsetjmp(lockstate.env, 0) != 0) 3274 lock_upgrade(rtld_bind_lock, &lockstate); 3275 if (handle == NULL || handle == RTLD_NEXT || 3276 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3277 3278 if ((obj = obj_from_addr(retaddr)) == NULL) { 3279 _rtld_error("Cannot determine caller's shared object"); 3280 lock_release(rtld_bind_lock, &lockstate); 3281 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3282 return NULL; 3283 } 3284 if (handle == NULL) { /* Just the caller's shared object. */ 3285 res = symlook_obj(&req, obj); 3286 if (res == 0) { 3287 def = req.sym_out; 3288 defobj = req.defobj_out; 3289 } 3290 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3291 handle == RTLD_SELF) { /* ... caller included */ 3292 if (handle == RTLD_NEXT) 3293 obj = globallist_next(obj); 3294 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3295 if (obj->marker) 3296 continue; 3297 res = symlook_obj(&req, obj); 3298 if (res == 0) { 3299 if (def == NULL || 3300 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3301 def = req.sym_out; 3302 defobj = req.defobj_out; 3303 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3304 break; 3305 } 3306 } 3307 } 3308 /* 3309 * Search the dynamic linker itself, and possibly resolve the 3310 * symbol from there. This is how the application links to 3311 * dynamic linker services such as dlopen. 3312 */ 3313 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3314 res = symlook_obj(&req, &obj_rtld); 3315 if (res == 0) { 3316 def = req.sym_out; 3317 defobj = req.defobj_out; 3318 } 3319 } 3320 } else { 3321 assert(handle == RTLD_DEFAULT); 3322 res = symlook_default(&req, obj); 3323 if (res == 0) { 3324 defobj = req.defobj_out; 3325 def = req.sym_out; 3326 } 3327 } 3328 } else { 3329 if ((obj = dlcheck(handle)) == NULL) { 3330 lock_release(rtld_bind_lock, &lockstate); 3331 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3332 return NULL; 3333 } 3334 3335 donelist_init(&donelist); 3336 if (obj->mainprog) { 3337 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3338 res = symlook_global(&req, &donelist); 3339 if (res == 0) { 3340 def = req.sym_out; 3341 defobj = req.defobj_out; 3342 } 3343 /* 3344 * Search the dynamic linker itself, and possibly resolve the 3345 * symbol from there. This is how the application links to 3346 * dynamic linker services such as dlopen. 3347 */ 3348 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3349 res = symlook_obj(&req, &obj_rtld); 3350 if (res == 0) { 3351 def = req.sym_out; 3352 defobj = req.defobj_out; 3353 } 3354 } 3355 } 3356 else { 3357 /* Search the whole DAG rooted at the given object. */ 3358 res = symlook_list(&req, &obj->dagmembers, &donelist); 3359 if (res == 0) { 3360 def = req.sym_out; 3361 defobj = req.defobj_out; 3362 } 3363 } 3364 } 3365 3366 if (def != NULL) { 3367 lock_release(rtld_bind_lock, &lockstate); 3368 3369 /* 3370 * The value required by the caller is derived from the value 3371 * of the symbol. this is simply the relocated value of the 3372 * symbol. 3373 */ 3374 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3375 sym = make_function_pointer(def, defobj); 3376 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3377 sym = rtld_resolve_ifunc(defobj, def); 3378 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3379 ti.ti_module = defobj->tlsindex; 3380 ti.ti_offset = def->st_value; 3381 sym = __tls_get_addr(&ti); 3382 } else 3383 sym = defobj->relocbase + def->st_value; 3384 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3385 return (sym); 3386 } 3387 3388 _rtld_error("Undefined symbol \"%s\"", name); 3389 lock_release(rtld_bind_lock, &lockstate); 3390 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3391 return NULL; 3392 } 3393 3394 void * 3395 dlsym(void *handle, const char *name) 3396 { 3397 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3398 SYMLOOK_DLSYM); 3399 } 3400 3401 dlfunc_t 3402 dlfunc(void *handle, const char *name) 3403 { 3404 union { 3405 void *d; 3406 dlfunc_t f; 3407 } rv; 3408 3409 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3410 SYMLOOK_DLSYM); 3411 return (rv.f); 3412 } 3413 3414 void * 3415 dlvsym(void *handle, const char *name, const char *version) 3416 { 3417 Ver_Entry ventry; 3418 3419 ventry.name = version; 3420 ventry.file = NULL; 3421 ventry.hash = elf_hash(version); 3422 ventry.flags= 0; 3423 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3424 SYMLOOK_DLSYM); 3425 } 3426 3427 int 3428 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3429 { 3430 const Obj_Entry *obj; 3431 RtldLockState lockstate; 3432 3433 rlock_acquire(rtld_bind_lock, &lockstate); 3434 obj = obj_from_addr(addr); 3435 if (obj == NULL) { 3436 _rtld_error("No shared object contains address"); 3437 lock_release(rtld_bind_lock, &lockstate); 3438 return (0); 3439 } 3440 rtld_fill_dl_phdr_info(obj, phdr_info); 3441 lock_release(rtld_bind_lock, &lockstate); 3442 return (1); 3443 } 3444 3445 int 3446 dladdr(const void *addr, Dl_info *info) 3447 { 3448 const Obj_Entry *obj; 3449 const Elf_Sym *def; 3450 void *symbol_addr; 3451 unsigned long symoffset; 3452 RtldLockState lockstate; 3453 3454 rlock_acquire(rtld_bind_lock, &lockstate); 3455 obj = obj_from_addr(addr); 3456 if (obj == NULL) { 3457 _rtld_error("No shared object contains address"); 3458 lock_release(rtld_bind_lock, &lockstate); 3459 return 0; 3460 } 3461 info->dli_fname = obj->path; 3462 info->dli_fbase = obj->mapbase; 3463 info->dli_saddr = (void *)0; 3464 info->dli_sname = NULL; 3465 3466 /* 3467 * Walk the symbol list looking for the symbol whose address is 3468 * closest to the address sent in. 3469 */ 3470 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3471 def = obj->symtab + symoffset; 3472 3473 /* 3474 * For skip the symbol if st_shndx is either SHN_UNDEF or 3475 * SHN_COMMON. 3476 */ 3477 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3478 continue; 3479 3480 /* 3481 * If the symbol is greater than the specified address, or if it 3482 * is further away from addr than the current nearest symbol, 3483 * then reject it. 3484 */ 3485 symbol_addr = obj->relocbase + def->st_value; 3486 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3487 continue; 3488 3489 /* Update our idea of the nearest symbol. */ 3490 info->dli_sname = obj->strtab + def->st_name; 3491 info->dli_saddr = symbol_addr; 3492 3493 /* Exact match? */ 3494 if (info->dli_saddr == addr) 3495 break; 3496 } 3497 lock_release(rtld_bind_lock, &lockstate); 3498 return 1; 3499 } 3500 3501 int 3502 dlinfo(void *handle, int request, void *p) 3503 { 3504 const Obj_Entry *obj; 3505 RtldLockState lockstate; 3506 int error; 3507 3508 rlock_acquire(rtld_bind_lock, &lockstate); 3509 3510 if (handle == NULL || handle == RTLD_SELF) { 3511 void *retaddr; 3512 3513 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3514 if ((obj = obj_from_addr(retaddr)) == NULL) 3515 _rtld_error("Cannot determine caller's shared object"); 3516 } else 3517 obj = dlcheck(handle); 3518 3519 if (obj == NULL) { 3520 lock_release(rtld_bind_lock, &lockstate); 3521 return (-1); 3522 } 3523 3524 error = 0; 3525 switch (request) { 3526 case RTLD_DI_LINKMAP: 3527 *((struct link_map const **)p) = &obj->linkmap; 3528 break; 3529 case RTLD_DI_ORIGIN: 3530 error = rtld_dirname(obj->path, p); 3531 break; 3532 3533 case RTLD_DI_SERINFOSIZE: 3534 case RTLD_DI_SERINFO: 3535 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3536 break; 3537 3538 default: 3539 _rtld_error("Invalid request %d passed to dlinfo()", request); 3540 error = -1; 3541 } 3542 3543 lock_release(rtld_bind_lock, &lockstate); 3544 3545 return (error); 3546 } 3547 3548 static void 3549 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3550 { 3551 3552 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3553 phdr_info->dlpi_name = obj->path; 3554 phdr_info->dlpi_phdr = obj->phdr; 3555 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3556 phdr_info->dlpi_tls_modid = obj->tlsindex; 3557 phdr_info->dlpi_tls_data = obj->tlsinit; 3558 phdr_info->dlpi_adds = obj_loads; 3559 phdr_info->dlpi_subs = obj_loads - obj_count; 3560 } 3561 3562 int 3563 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3564 { 3565 struct dl_phdr_info phdr_info; 3566 Obj_Entry *obj, marker; 3567 RtldLockState bind_lockstate, phdr_lockstate; 3568 int error; 3569 3570 bzero(&marker, sizeof(marker)); 3571 marker.marker = true; 3572 error = 0; 3573 3574 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3575 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3576 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3577 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3578 rtld_fill_dl_phdr_info(obj, &phdr_info); 3579 lock_release(rtld_bind_lock, &bind_lockstate); 3580 3581 error = callback(&phdr_info, sizeof phdr_info, param); 3582 3583 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3584 obj = globallist_next(&marker); 3585 TAILQ_REMOVE(&obj_list, &marker, next); 3586 if (error != 0) { 3587 lock_release(rtld_bind_lock, &bind_lockstate); 3588 lock_release(rtld_phdr_lock, &phdr_lockstate); 3589 return (error); 3590 } 3591 } 3592 3593 if (error == 0) { 3594 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3595 lock_release(rtld_bind_lock, &bind_lockstate); 3596 error = callback(&phdr_info, sizeof(phdr_info), param); 3597 } 3598 lock_release(rtld_phdr_lock, &phdr_lockstate); 3599 return (error); 3600 } 3601 3602 static void * 3603 fill_search_info(const char *dir, size_t dirlen, void *param) 3604 { 3605 struct fill_search_info_args *arg; 3606 3607 arg = param; 3608 3609 if (arg->request == RTLD_DI_SERINFOSIZE) { 3610 arg->serinfo->dls_cnt ++; 3611 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3612 } else { 3613 struct dl_serpath *s_entry; 3614 3615 s_entry = arg->serpath; 3616 s_entry->dls_name = arg->strspace; 3617 s_entry->dls_flags = arg->flags; 3618 3619 strncpy(arg->strspace, dir, dirlen); 3620 arg->strspace[dirlen] = '\0'; 3621 3622 arg->strspace += dirlen + 1; 3623 arg->serpath++; 3624 } 3625 3626 return (NULL); 3627 } 3628 3629 static int 3630 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3631 { 3632 struct dl_serinfo _info; 3633 struct fill_search_info_args args; 3634 3635 args.request = RTLD_DI_SERINFOSIZE; 3636 args.serinfo = &_info; 3637 3638 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3639 _info.dls_cnt = 0; 3640 3641 path_enumerate(obj->rpath, fill_search_info, &args); 3642 path_enumerate(ld_library_path, fill_search_info, &args); 3643 path_enumerate(obj->runpath, fill_search_info, &args); 3644 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3645 if (!obj->z_nodeflib) 3646 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3647 3648 3649 if (request == RTLD_DI_SERINFOSIZE) { 3650 info->dls_size = _info.dls_size; 3651 info->dls_cnt = _info.dls_cnt; 3652 return (0); 3653 } 3654 3655 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3656 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3657 return (-1); 3658 } 3659 3660 args.request = RTLD_DI_SERINFO; 3661 args.serinfo = info; 3662 args.serpath = &info->dls_serpath[0]; 3663 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3664 3665 args.flags = LA_SER_RUNPATH; 3666 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3667 return (-1); 3668 3669 args.flags = LA_SER_LIBPATH; 3670 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3671 return (-1); 3672 3673 args.flags = LA_SER_RUNPATH; 3674 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3675 return (-1); 3676 3677 args.flags = LA_SER_CONFIG; 3678 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3679 != NULL) 3680 return (-1); 3681 3682 args.flags = LA_SER_DEFAULT; 3683 if (!obj->z_nodeflib && 3684 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3685 return (-1); 3686 return (0); 3687 } 3688 3689 static int 3690 rtld_dirname(const char *path, char *bname) 3691 { 3692 const char *endp; 3693 3694 /* Empty or NULL string gets treated as "." */ 3695 if (path == NULL || *path == '\0') { 3696 bname[0] = '.'; 3697 bname[1] = '\0'; 3698 return (0); 3699 } 3700 3701 /* Strip trailing slashes */ 3702 endp = path + strlen(path) - 1; 3703 while (endp > path && *endp == '/') 3704 endp--; 3705 3706 /* Find the start of the dir */ 3707 while (endp > path && *endp != '/') 3708 endp--; 3709 3710 /* Either the dir is "/" or there are no slashes */ 3711 if (endp == path) { 3712 bname[0] = *endp == '/' ? '/' : '.'; 3713 bname[1] = '\0'; 3714 return (0); 3715 } else { 3716 do { 3717 endp--; 3718 } while (endp > path && *endp == '/'); 3719 } 3720 3721 if (endp - path + 2 > PATH_MAX) 3722 { 3723 _rtld_error("Filename is too long: %s", path); 3724 return(-1); 3725 } 3726 3727 strncpy(bname, path, endp - path + 1); 3728 bname[endp - path + 1] = '\0'; 3729 return (0); 3730 } 3731 3732 static int 3733 rtld_dirname_abs(const char *path, char *base) 3734 { 3735 char *last; 3736 3737 if (realpath(path, base) == NULL) 3738 return (-1); 3739 dbg("%s -> %s", path, base); 3740 last = strrchr(base, '/'); 3741 if (last == NULL) 3742 return (-1); 3743 if (last != base) 3744 *last = '\0'; 3745 return (0); 3746 } 3747 3748 static void 3749 linkmap_add(Obj_Entry *obj) 3750 { 3751 struct link_map *l = &obj->linkmap; 3752 struct link_map *prev; 3753 3754 obj->linkmap.l_name = obj->path; 3755 obj->linkmap.l_addr = obj->mapbase; 3756 obj->linkmap.l_ld = obj->dynamic; 3757 #ifdef __mips__ 3758 /* GDB needs load offset on MIPS to use the symbols */ 3759 obj->linkmap.l_offs = obj->relocbase; 3760 #endif 3761 3762 if (r_debug.r_map == NULL) { 3763 r_debug.r_map = l; 3764 return; 3765 } 3766 3767 /* 3768 * Scan to the end of the list, but not past the entry for the 3769 * dynamic linker, which we want to keep at the very end. 3770 */ 3771 for (prev = r_debug.r_map; 3772 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3773 prev = prev->l_next) 3774 ; 3775 3776 /* Link in the new entry. */ 3777 l->l_prev = prev; 3778 l->l_next = prev->l_next; 3779 if (l->l_next != NULL) 3780 l->l_next->l_prev = l; 3781 prev->l_next = l; 3782 } 3783 3784 static void 3785 linkmap_delete(Obj_Entry *obj) 3786 { 3787 struct link_map *l = &obj->linkmap; 3788 3789 if (l->l_prev == NULL) { 3790 if ((r_debug.r_map = l->l_next) != NULL) 3791 l->l_next->l_prev = NULL; 3792 return; 3793 } 3794 3795 if ((l->l_prev->l_next = l->l_next) != NULL) 3796 l->l_next->l_prev = l->l_prev; 3797 } 3798 3799 /* 3800 * Function for the debugger to set a breakpoint on to gain control. 3801 * 3802 * The two parameters allow the debugger to easily find and determine 3803 * what the runtime loader is doing and to whom it is doing it. 3804 * 3805 * When the loadhook trap is hit (r_debug_state, set at program 3806 * initialization), the arguments can be found on the stack: 3807 * 3808 * +8 struct link_map *m 3809 * +4 struct r_debug *rd 3810 * +0 RetAddr 3811 */ 3812 void 3813 r_debug_state(struct r_debug* rd, struct link_map *m) 3814 { 3815 /* 3816 * The following is a hack to force the compiler to emit calls to 3817 * this function, even when optimizing. If the function is empty, 3818 * the compiler is not obliged to emit any code for calls to it, 3819 * even when marked __noinline. However, gdb depends on those 3820 * calls being made. 3821 */ 3822 __compiler_membar(); 3823 } 3824 3825 /* 3826 * A function called after init routines have completed. This can be used to 3827 * break before a program's entry routine is called, and can be used when 3828 * main is not available in the symbol table. 3829 */ 3830 void 3831 _r_debug_postinit(struct link_map *m) 3832 { 3833 3834 /* See r_debug_state(). */ 3835 __compiler_membar(); 3836 } 3837 3838 /* 3839 * Get address of the pointer variable in the main program. 3840 * Prefer non-weak symbol over the weak one. 3841 */ 3842 static const void ** 3843 get_program_var_addr(const char *name, RtldLockState *lockstate) 3844 { 3845 SymLook req; 3846 DoneList donelist; 3847 3848 symlook_init(&req, name); 3849 req.lockstate = lockstate; 3850 donelist_init(&donelist); 3851 if (symlook_global(&req, &donelist) != 0) 3852 return (NULL); 3853 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3854 return ((const void **)make_function_pointer(req.sym_out, 3855 req.defobj_out)); 3856 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3857 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3858 else 3859 return ((const void **)(req.defobj_out->relocbase + 3860 req.sym_out->st_value)); 3861 } 3862 3863 /* 3864 * Set a pointer variable in the main program to the given value. This 3865 * is used to set key variables such as "environ" before any of the 3866 * init functions are called. 3867 */ 3868 static void 3869 set_program_var(const char *name, const void *value) 3870 { 3871 const void **addr; 3872 3873 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3874 dbg("\"%s\": *%p <-- %p", name, addr, value); 3875 *addr = value; 3876 } 3877 } 3878 3879 /* 3880 * Search the global objects, including dependencies and main object, 3881 * for the given symbol. 3882 */ 3883 static int 3884 symlook_global(SymLook *req, DoneList *donelist) 3885 { 3886 SymLook req1; 3887 const Objlist_Entry *elm; 3888 int res; 3889 3890 symlook_init_from_req(&req1, req); 3891 3892 /* Search all objects loaded at program start up. */ 3893 if (req->defobj_out == NULL || 3894 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3895 res = symlook_list(&req1, &list_main, donelist); 3896 if (res == 0 && (req->defobj_out == NULL || 3897 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3898 req->sym_out = req1.sym_out; 3899 req->defobj_out = req1.defobj_out; 3900 assert(req->defobj_out != NULL); 3901 } 3902 } 3903 3904 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3905 STAILQ_FOREACH(elm, &list_global, link) { 3906 if (req->defobj_out != NULL && 3907 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3908 break; 3909 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3910 if (res == 0 && (req->defobj_out == NULL || 3911 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3912 req->sym_out = req1.sym_out; 3913 req->defobj_out = req1.defobj_out; 3914 assert(req->defobj_out != NULL); 3915 } 3916 } 3917 3918 return (req->sym_out != NULL ? 0 : ESRCH); 3919 } 3920 3921 /* 3922 * Given a symbol name in a referencing object, find the corresponding 3923 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3924 * no definition was found. Returns a pointer to the Obj_Entry of the 3925 * defining object via the reference parameter DEFOBJ_OUT. 3926 */ 3927 static int 3928 symlook_default(SymLook *req, const Obj_Entry *refobj) 3929 { 3930 DoneList donelist; 3931 const Objlist_Entry *elm; 3932 SymLook req1; 3933 int res; 3934 3935 donelist_init(&donelist); 3936 symlook_init_from_req(&req1, req); 3937 3938 /* Look first in the referencing object if linked symbolically. */ 3939 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3940 res = symlook_obj(&req1, refobj); 3941 if (res == 0) { 3942 req->sym_out = req1.sym_out; 3943 req->defobj_out = req1.defobj_out; 3944 assert(req->defobj_out != NULL); 3945 } 3946 } 3947 3948 symlook_global(req, &donelist); 3949 3950 /* Search all dlopened DAGs containing the referencing object. */ 3951 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3952 if (req->sym_out != NULL && 3953 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3954 break; 3955 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3956 if (res == 0 && (req->sym_out == NULL || 3957 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3958 req->sym_out = req1.sym_out; 3959 req->defobj_out = req1.defobj_out; 3960 assert(req->defobj_out != NULL); 3961 } 3962 } 3963 3964 /* 3965 * Search the dynamic linker itself, and possibly resolve the 3966 * symbol from there. This is how the application links to 3967 * dynamic linker services such as dlopen. 3968 */ 3969 if (req->sym_out == NULL || 3970 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3971 res = symlook_obj(&req1, &obj_rtld); 3972 if (res == 0) { 3973 req->sym_out = req1.sym_out; 3974 req->defobj_out = req1.defobj_out; 3975 assert(req->defobj_out != NULL); 3976 } 3977 } 3978 3979 return (req->sym_out != NULL ? 0 : ESRCH); 3980 } 3981 3982 static int 3983 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3984 { 3985 const Elf_Sym *def; 3986 const Obj_Entry *defobj; 3987 const Objlist_Entry *elm; 3988 SymLook req1; 3989 int res; 3990 3991 def = NULL; 3992 defobj = NULL; 3993 STAILQ_FOREACH(elm, objlist, link) { 3994 if (donelist_check(dlp, elm->obj)) 3995 continue; 3996 symlook_init_from_req(&req1, req); 3997 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3998 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3999 def = req1.sym_out; 4000 defobj = req1.defobj_out; 4001 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4002 break; 4003 } 4004 } 4005 } 4006 if (def != NULL) { 4007 req->sym_out = def; 4008 req->defobj_out = defobj; 4009 return (0); 4010 } 4011 return (ESRCH); 4012 } 4013 4014 /* 4015 * Search the chain of DAGS cointed to by the given Needed_Entry 4016 * for a symbol of the given name. Each DAG is scanned completely 4017 * before advancing to the next one. Returns a pointer to the symbol, 4018 * or NULL if no definition was found. 4019 */ 4020 static int 4021 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4022 { 4023 const Elf_Sym *def; 4024 const Needed_Entry *n; 4025 const Obj_Entry *defobj; 4026 SymLook req1; 4027 int res; 4028 4029 def = NULL; 4030 defobj = NULL; 4031 symlook_init_from_req(&req1, req); 4032 for (n = needed; n != NULL; n = n->next) { 4033 if (n->obj == NULL || 4034 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4035 continue; 4036 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4037 def = req1.sym_out; 4038 defobj = req1.defobj_out; 4039 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4040 break; 4041 } 4042 } 4043 if (def != NULL) { 4044 req->sym_out = def; 4045 req->defobj_out = defobj; 4046 return (0); 4047 } 4048 return (ESRCH); 4049 } 4050 4051 /* 4052 * Search the symbol table of a single shared object for a symbol of 4053 * the given name and version, if requested. Returns a pointer to the 4054 * symbol, or NULL if no definition was found. If the object is 4055 * filter, return filtered symbol from filtee. 4056 * 4057 * The symbol's hash value is passed in for efficiency reasons; that 4058 * eliminates many recomputations of the hash value. 4059 */ 4060 int 4061 symlook_obj(SymLook *req, const Obj_Entry *obj) 4062 { 4063 DoneList donelist; 4064 SymLook req1; 4065 int flags, res, mres; 4066 4067 /* 4068 * If there is at least one valid hash at this point, we prefer to 4069 * use the faster GNU version if available. 4070 */ 4071 if (obj->valid_hash_gnu) 4072 mres = symlook_obj1_gnu(req, obj); 4073 else if (obj->valid_hash_sysv) 4074 mres = symlook_obj1_sysv(req, obj); 4075 else 4076 return (EINVAL); 4077 4078 if (mres == 0) { 4079 if (obj->needed_filtees != NULL) { 4080 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4081 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4082 donelist_init(&donelist); 4083 symlook_init_from_req(&req1, req); 4084 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4085 if (res == 0) { 4086 req->sym_out = req1.sym_out; 4087 req->defobj_out = req1.defobj_out; 4088 } 4089 return (res); 4090 } 4091 if (obj->needed_aux_filtees != NULL) { 4092 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4093 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4094 donelist_init(&donelist); 4095 symlook_init_from_req(&req1, req); 4096 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4097 if (res == 0) { 4098 req->sym_out = req1.sym_out; 4099 req->defobj_out = req1.defobj_out; 4100 return (res); 4101 } 4102 } 4103 } 4104 return (mres); 4105 } 4106 4107 /* Symbol match routine common to both hash functions */ 4108 static bool 4109 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4110 const unsigned long symnum) 4111 { 4112 Elf_Versym verndx; 4113 const Elf_Sym *symp; 4114 const char *strp; 4115 4116 symp = obj->symtab + symnum; 4117 strp = obj->strtab + symp->st_name; 4118 4119 switch (ELF_ST_TYPE(symp->st_info)) { 4120 case STT_FUNC: 4121 case STT_NOTYPE: 4122 case STT_OBJECT: 4123 case STT_COMMON: 4124 case STT_GNU_IFUNC: 4125 if (symp->st_value == 0) 4126 return (false); 4127 /* fallthrough */ 4128 case STT_TLS: 4129 if (symp->st_shndx != SHN_UNDEF) 4130 break; 4131 #ifndef __mips__ 4132 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4133 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4134 break; 4135 /* fallthrough */ 4136 #endif 4137 default: 4138 return (false); 4139 } 4140 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4141 return (false); 4142 4143 if (req->ventry == NULL) { 4144 if (obj->versyms != NULL) { 4145 verndx = VER_NDX(obj->versyms[symnum]); 4146 if (verndx > obj->vernum) { 4147 _rtld_error( 4148 "%s: symbol %s references wrong version %d", 4149 obj->path, obj->strtab + symnum, verndx); 4150 return (false); 4151 } 4152 /* 4153 * If we are not called from dlsym (i.e. this 4154 * is a normal relocation from unversioned 4155 * binary), accept the symbol immediately if 4156 * it happens to have first version after this 4157 * shared object became versioned. Otherwise, 4158 * if symbol is versioned and not hidden, 4159 * remember it. If it is the only symbol with 4160 * this name exported by the shared object, it 4161 * will be returned as a match by the calling 4162 * function. If symbol is global (verndx < 2) 4163 * accept it unconditionally. 4164 */ 4165 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4166 verndx == VER_NDX_GIVEN) { 4167 result->sym_out = symp; 4168 return (true); 4169 } 4170 else if (verndx >= VER_NDX_GIVEN) { 4171 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4172 == 0) { 4173 if (result->vsymp == NULL) 4174 result->vsymp = symp; 4175 result->vcount++; 4176 } 4177 return (false); 4178 } 4179 } 4180 result->sym_out = symp; 4181 return (true); 4182 } 4183 if (obj->versyms == NULL) { 4184 if (object_match_name(obj, req->ventry->name)) { 4185 _rtld_error("%s: object %s should provide version %s " 4186 "for symbol %s", obj_rtld.path, obj->path, 4187 req->ventry->name, obj->strtab + symnum); 4188 return (false); 4189 } 4190 } else { 4191 verndx = VER_NDX(obj->versyms[symnum]); 4192 if (verndx > obj->vernum) { 4193 _rtld_error("%s: symbol %s references wrong version %d", 4194 obj->path, obj->strtab + symnum, verndx); 4195 return (false); 4196 } 4197 if (obj->vertab[verndx].hash != req->ventry->hash || 4198 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4199 /* 4200 * Version does not match. Look if this is a 4201 * global symbol and if it is not hidden. If 4202 * global symbol (verndx < 2) is available, 4203 * use it. Do not return symbol if we are 4204 * called by dlvsym, because dlvsym looks for 4205 * a specific version and default one is not 4206 * what dlvsym wants. 4207 */ 4208 if ((req->flags & SYMLOOK_DLSYM) || 4209 (verndx >= VER_NDX_GIVEN) || 4210 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4211 return (false); 4212 } 4213 } 4214 result->sym_out = symp; 4215 return (true); 4216 } 4217 4218 /* 4219 * Search for symbol using SysV hash function. 4220 * obj->buckets is known not to be NULL at this point; the test for this was 4221 * performed with the obj->valid_hash_sysv assignment. 4222 */ 4223 static int 4224 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4225 { 4226 unsigned long symnum; 4227 Sym_Match_Result matchres; 4228 4229 matchres.sym_out = NULL; 4230 matchres.vsymp = NULL; 4231 matchres.vcount = 0; 4232 4233 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4234 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4235 if (symnum >= obj->nchains) 4236 return (ESRCH); /* Bad object */ 4237 4238 if (matched_symbol(req, obj, &matchres, symnum)) { 4239 req->sym_out = matchres.sym_out; 4240 req->defobj_out = obj; 4241 return (0); 4242 } 4243 } 4244 if (matchres.vcount == 1) { 4245 req->sym_out = matchres.vsymp; 4246 req->defobj_out = obj; 4247 return (0); 4248 } 4249 return (ESRCH); 4250 } 4251 4252 /* Search for symbol using GNU hash function */ 4253 static int 4254 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4255 { 4256 Elf_Addr bloom_word; 4257 const Elf32_Word *hashval; 4258 Elf32_Word bucket; 4259 Sym_Match_Result matchres; 4260 unsigned int h1, h2; 4261 unsigned long symnum; 4262 4263 matchres.sym_out = NULL; 4264 matchres.vsymp = NULL; 4265 matchres.vcount = 0; 4266 4267 /* Pick right bitmask word from Bloom filter array */ 4268 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4269 obj->maskwords_bm_gnu]; 4270 4271 /* Calculate modulus word size of gnu hash and its derivative */ 4272 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4273 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4274 4275 /* Filter out the "definitely not in set" queries */ 4276 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4277 return (ESRCH); 4278 4279 /* Locate hash chain and corresponding value element*/ 4280 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4281 if (bucket == 0) 4282 return (ESRCH); 4283 hashval = &obj->chain_zero_gnu[bucket]; 4284 do { 4285 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4286 symnum = hashval - obj->chain_zero_gnu; 4287 if (matched_symbol(req, obj, &matchres, symnum)) { 4288 req->sym_out = matchres.sym_out; 4289 req->defobj_out = obj; 4290 return (0); 4291 } 4292 } 4293 } while ((*hashval++ & 1) == 0); 4294 if (matchres.vcount == 1) { 4295 req->sym_out = matchres.vsymp; 4296 req->defobj_out = obj; 4297 return (0); 4298 } 4299 return (ESRCH); 4300 } 4301 4302 static void 4303 trace_loaded_objects(Obj_Entry *obj) 4304 { 4305 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4306 int c; 4307 4308 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4309 main_local = ""; 4310 4311 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4312 fmt1 = "\t%o => %p (%x)\n"; 4313 4314 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4315 fmt2 = "\t%o (%x)\n"; 4316 4317 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4318 4319 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4320 Needed_Entry *needed; 4321 char *name, *path; 4322 bool is_lib; 4323 4324 if (obj->marker) 4325 continue; 4326 if (list_containers && obj->needed != NULL) 4327 rtld_printf("%s:\n", obj->path); 4328 for (needed = obj->needed; needed; needed = needed->next) { 4329 if (needed->obj != NULL) { 4330 if (needed->obj->traced && !list_containers) 4331 continue; 4332 needed->obj->traced = true; 4333 path = needed->obj->path; 4334 } else 4335 path = "not found"; 4336 4337 name = (char *)obj->strtab + needed->name; 4338 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4339 4340 fmt = is_lib ? fmt1 : fmt2; 4341 while ((c = *fmt++) != '\0') { 4342 switch (c) { 4343 default: 4344 rtld_putchar(c); 4345 continue; 4346 case '\\': 4347 switch (c = *fmt) { 4348 case '\0': 4349 continue; 4350 case 'n': 4351 rtld_putchar('\n'); 4352 break; 4353 case 't': 4354 rtld_putchar('\t'); 4355 break; 4356 } 4357 break; 4358 case '%': 4359 switch (c = *fmt) { 4360 case '\0': 4361 continue; 4362 case '%': 4363 default: 4364 rtld_putchar(c); 4365 break; 4366 case 'A': 4367 rtld_putstr(main_local); 4368 break; 4369 case 'a': 4370 rtld_putstr(obj_main->path); 4371 break; 4372 case 'o': 4373 rtld_putstr(name); 4374 break; 4375 #if 0 4376 case 'm': 4377 rtld_printf("%d", sodp->sod_major); 4378 break; 4379 case 'n': 4380 rtld_printf("%d", sodp->sod_minor); 4381 break; 4382 #endif 4383 case 'p': 4384 rtld_putstr(path); 4385 break; 4386 case 'x': 4387 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4388 0); 4389 break; 4390 } 4391 break; 4392 } 4393 ++fmt; 4394 } 4395 } 4396 } 4397 } 4398 4399 /* 4400 * Unload a dlopened object and its dependencies from memory and from 4401 * our data structures. It is assumed that the DAG rooted in the 4402 * object has already been unreferenced, and that the object has a 4403 * reference count of 0. 4404 */ 4405 static void 4406 unload_object(Obj_Entry *root) 4407 { 4408 Obj_Entry *obj, *obj1; 4409 4410 assert(root->refcount == 0); 4411 4412 /* 4413 * Pass over the DAG removing unreferenced objects from 4414 * appropriate lists. 4415 */ 4416 unlink_object(root); 4417 4418 /* Unmap all objects that are no longer referenced. */ 4419 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4420 if (obj->marker || obj->refcount != 0) 4421 continue; 4422 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4423 obj->mapsize, 0, obj->path); 4424 dbg("unloading \"%s\"", obj->path); 4425 unload_filtees(root); 4426 munmap(obj->mapbase, obj->mapsize); 4427 linkmap_delete(obj); 4428 TAILQ_REMOVE(&obj_list, obj, next); 4429 obj_count--; 4430 obj_free(obj); 4431 } 4432 } 4433 4434 static void 4435 unlink_object(Obj_Entry *root) 4436 { 4437 Objlist_Entry *elm; 4438 4439 if (root->refcount == 0) { 4440 /* Remove the object from the RTLD_GLOBAL list. */ 4441 objlist_remove(&list_global, root); 4442 4443 /* Remove the object from all objects' DAG lists. */ 4444 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4445 objlist_remove(&elm->obj->dldags, root); 4446 if (elm->obj != root) 4447 unlink_object(elm->obj); 4448 } 4449 } 4450 } 4451 4452 static void 4453 ref_dag(Obj_Entry *root) 4454 { 4455 Objlist_Entry *elm; 4456 4457 assert(root->dag_inited); 4458 STAILQ_FOREACH(elm, &root->dagmembers, link) 4459 elm->obj->refcount++; 4460 } 4461 4462 static void 4463 unref_dag(Obj_Entry *root) 4464 { 4465 Objlist_Entry *elm; 4466 4467 assert(root->dag_inited); 4468 STAILQ_FOREACH(elm, &root->dagmembers, link) 4469 elm->obj->refcount--; 4470 } 4471 4472 /* 4473 * Common code for MD __tls_get_addr(). 4474 */ 4475 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4476 static void * 4477 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4478 { 4479 Elf_Addr *newdtv, *dtv; 4480 RtldLockState lockstate; 4481 int to_copy; 4482 4483 dtv = *dtvp; 4484 /* Check dtv generation in case new modules have arrived */ 4485 if (dtv[0] != tls_dtv_generation) { 4486 wlock_acquire(rtld_bind_lock, &lockstate); 4487 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4488 to_copy = dtv[1]; 4489 if (to_copy > tls_max_index) 4490 to_copy = tls_max_index; 4491 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4492 newdtv[0] = tls_dtv_generation; 4493 newdtv[1] = tls_max_index; 4494 free(dtv); 4495 lock_release(rtld_bind_lock, &lockstate); 4496 dtv = *dtvp = newdtv; 4497 } 4498 4499 /* Dynamically allocate module TLS if necessary */ 4500 if (dtv[index + 1] == 0) { 4501 /* Signal safe, wlock will block out signals. */ 4502 wlock_acquire(rtld_bind_lock, &lockstate); 4503 if (!dtv[index + 1]) 4504 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4505 lock_release(rtld_bind_lock, &lockstate); 4506 } 4507 return ((void *)(dtv[index + 1] + offset)); 4508 } 4509 4510 void * 4511 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4512 { 4513 Elf_Addr *dtv; 4514 4515 dtv = *dtvp; 4516 /* Check dtv generation in case new modules have arrived */ 4517 if (__predict_true(dtv[0] == tls_dtv_generation && 4518 dtv[index + 1] != 0)) 4519 return ((void *)(dtv[index + 1] + offset)); 4520 return (tls_get_addr_slow(dtvp, index, offset)); 4521 } 4522 4523 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4524 defined(__powerpc__) || defined(__riscv__) 4525 4526 /* 4527 * Allocate Static TLS using the Variant I method. 4528 */ 4529 void * 4530 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4531 { 4532 Obj_Entry *obj; 4533 char *tcb; 4534 Elf_Addr **tls; 4535 Elf_Addr *dtv; 4536 Elf_Addr addr; 4537 int i; 4538 4539 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4540 return (oldtcb); 4541 4542 assert(tcbsize >= TLS_TCB_SIZE); 4543 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4544 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4545 4546 if (oldtcb != NULL) { 4547 memcpy(tls, oldtcb, tls_static_space); 4548 free(oldtcb); 4549 4550 /* Adjust the DTV. */ 4551 dtv = tls[0]; 4552 for (i = 0; i < dtv[1]; i++) { 4553 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4554 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4555 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4556 } 4557 } 4558 } else { 4559 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4560 tls[0] = dtv; 4561 dtv[0] = tls_dtv_generation; 4562 dtv[1] = tls_max_index; 4563 4564 for (obj = globallist_curr(objs); obj != NULL; 4565 obj = globallist_next(obj)) { 4566 if (obj->tlsoffset > 0) { 4567 addr = (Elf_Addr)tls + obj->tlsoffset; 4568 if (obj->tlsinitsize > 0) 4569 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4570 if (obj->tlssize > obj->tlsinitsize) 4571 memset((void*) (addr + obj->tlsinitsize), 0, 4572 obj->tlssize - obj->tlsinitsize); 4573 dtv[obj->tlsindex + 1] = addr; 4574 } 4575 } 4576 } 4577 4578 return (tcb); 4579 } 4580 4581 void 4582 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4583 { 4584 Elf_Addr *dtv; 4585 Elf_Addr tlsstart, tlsend; 4586 int dtvsize, i; 4587 4588 assert(tcbsize >= TLS_TCB_SIZE); 4589 4590 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4591 tlsend = tlsstart + tls_static_space; 4592 4593 dtv = *(Elf_Addr **)tlsstart; 4594 dtvsize = dtv[1]; 4595 for (i = 0; i < dtvsize; i++) { 4596 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4597 free((void*)dtv[i+2]); 4598 } 4599 } 4600 free(dtv); 4601 free(tcb); 4602 } 4603 4604 #endif 4605 4606 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4607 4608 /* 4609 * Allocate Static TLS using the Variant II method. 4610 */ 4611 void * 4612 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4613 { 4614 Obj_Entry *obj; 4615 size_t size, ralign; 4616 char *tls; 4617 Elf_Addr *dtv, *olddtv; 4618 Elf_Addr segbase, oldsegbase, addr; 4619 int i; 4620 4621 ralign = tcbalign; 4622 if (tls_static_max_align > ralign) 4623 ralign = tls_static_max_align; 4624 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4625 4626 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4627 tls = malloc_aligned(size, ralign); 4628 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4629 4630 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4631 ((Elf_Addr*)segbase)[0] = segbase; 4632 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4633 4634 dtv[0] = tls_dtv_generation; 4635 dtv[1] = tls_max_index; 4636 4637 if (oldtls) { 4638 /* 4639 * Copy the static TLS block over whole. 4640 */ 4641 oldsegbase = (Elf_Addr) oldtls; 4642 memcpy((void *)(segbase - tls_static_space), 4643 (const void *)(oldsegbase - tls_static_space), 4644 tls_static_space); 4645 4646 /* 4647 * If any dynamic TLS blocks have been created tls_get_addr(), 4648 * move them over. 4649 */ 4650 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4651 for (i = 0; i < olddtv[1]; i++) { 4652 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4653 dtv[i+2] = olddtv[i+2]; 4654 olddtv[i+2] = 0; 4655 } 4656 } 4657 4658 /* 4659 * We assume that this block was the one we created with 4660 * allocate_initial_tls(). 4661 */ 4662 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4663 } else { 4664 obj = objs; 4665 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4666 if (obj->marker || obj->tlsoffset == 0) 4667 continue; 4668 addr = segbase - obj->tlsoffset; 4669 memset((void*) (addr + obj->tlsinitsize), 4670 0, obj->tlssize - obj->tlsinitsize); 4671 if (obj->tlsinit) 4672 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4673 dtv[obj->tlsindex + 1] = addr; 4674 } 4675 } 4676 4677 return (void*) segbase; 4678 } 4679 4680 void 4681 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4682 { 4683 Elf_Addr* dtv; 4684 size_t size, ralign; 4685 int dtvsize, i; 4686 Elf_Addr tlsstart, tlsend; 4687 4688 /* 4689 * Figure out the size of the initial TLS block so that we can 4690 * find stuff which ___tls_get_addr() allocated dynamically. 4691 */ 4692 ralign = tcbalign; 4693 if (tls_static_max_align > ralign) 4694 ralign = tls_static_max_align; 4695 size = round(tls_static_space, ralign); 4696 4697 dtv = ((Elf_Addr**)tls)[1]; 4698 dtvsize = dtv[1]; 4699 tlsend = (Elf_Addr) tls; 4700 tlsstart = tlsend - size; 4701 for (i = 0; i < dtvsize; i++) { 4702 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4703 free_aligned((void *)dtv[i + 2]); 4704 } 4705 } 4706 4707 free_aligned((void *)tlsstart); 4708 free((void*) dtv); 4709 } 4710 4711 #endif 4712 4713 /* 4714 * Allocate TLS block for module with given index. 4715 */ 4716 void * 4717 allocate_module_tls(int index) 4718 { 4719 Obj_Entry* obj; 4720 char* p; 4721 4722 TAILQ_FOREACH(obj, &obj_list, next) { 4723 if (obj->marker) 4724 continue; 4725 if (obj->tlsindex == index) 4726 break; 4727 } 4728 if (!obj) { 4729 _rtld_error("Can't find module with TLS index %d", index); 4730 rtld_die(); 4731 } 4732 4733 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4734 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4735 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4736 4737 return p; 4738 } 4739 4740 bool 4741 allocate_tls_offset(Obj_Entry *obj) 4742 { 4743 size_t off; 4744 4745 if (obj->tls_done) 4746 return true; 4747 4748 if (obj->tlssize == 0) { 4749 obj->tls_done = true; 4750 return true; 4751 } 4752 4753 if (tls_last_offset == 0) 4754 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4755 else 4756 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4757 obj->tlssize, obj->tlsalign); 4758 4759 /* 4760 * If we have already fixed the size of the static TLS block, we 4761 * must stay within that size. When allocating the static TLS, we 4762 * leave a small amount of space spare to be used for dynamically 4763 * loading modules which use static TLS. 4764 */ 4765 if (tls_static_space != 0) { 4766 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4767 return false; 4768 } else if (obj->tlsalign > tls_static_max_align) { 4769 tls_static_max_align = obj->tlsalign; 4770 } 4771 4772 tls_last_offset = obj->tlsoffset = off; 4773 tls_last_size = obj->tlssize; 4774 obj->tls_done = true; 4775 4776 return true; 4777 } 4778 4779 void 4780 free_tls_offset(Obj_Entry *obj) 4781 { 4782 4783 /* 4784 * If we were the last thing to allocate out of the static TLS 4785 * block, we give our space back to the 'allocator'. This is a 4786 * simplistic workaround to allow libGL.so.1 to be loaded and 4787 * unloaded multiple times. 4788 */ 4789 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4790 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4791 tls_last_offset -= obj->tlssize; 4792 tls_last_size = 0; 4793 } 4794 } 4795 4796 void * 4797 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4798 { 4799 void *ret; 4800 RtldLockState lockstate; 4801 4802 wlock_acquire(rtld_bind_lock, &lockstate); 4803 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4804 tcbsize, tcbalign); 4805 lock_release(rtld_bind_lock, &lockstate); 4806 return (ret); 4807 } 4808 4809 void 4810 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4811 { 4812 RtldLockState lockstate; 4813 4814 wlock_acquire(rtld_bind_lock, &lockstate); 4815 free_tls(tcb, tcbsize, tcbalign); 4816 lock_release(rtld_bind_lock, &lockstate); 4817 } 4818 4819 static void 4820 object_add_name(Obj_Entry *obj, const char *name) 4821 { 4822 Name_Entry *entry; 4823 size_t len; 4824 4825 len = strlen(name); 4826 entry = malloc(sizeof(Name_Entry) + len); 4827 4828 if (entry != NULL) { 4829 strcpy(entry->name, name); 4830 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4831 } 4832 } 4833 4834 static int 4835 object_match_name(const Obj_Entry *obj, const char *name) 4836 { 4837 Name_Entry *entry; 4838 4839 STAILQ_FOREACH(entry, &obj->names, link) { 4840 if (strcmp(name, entry->name) == 0) 4841 return (1); 4842 } 4843 return (0); 4844 } 4845 4846 static Obj_Entry * 4847 locate_dependency(const Obj_Entry *obj, const char *name) 4848 { 4849 const Objlist_Entry *entry; 4850 const Needed_Entry *needed; 4851 4852 STAILQ_FOREACH(entry, &list_main, link) { 4853 if (object_match_name(entry->obj, name)) 4854 return entry->obj; 4855 } 4856 4857 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4858 if (strcmp(obj->strtab + needed->name, name) == 0 || 4859 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4860 /* 4861 * If there is DT_NEEDED for the name we are looking for, 4862 * we are all set. Note that object might not be found if 4863 * dependency was not loaded yet, so the function can 4864 * return NULL here. This is expected and handled 4865 * properly by the caller. 4866 */ 4867 return (needed->obj); 4868 } 4869 } 4870 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4871 obj->path, name); 4872 rtld_die(); 4873 } 4874 4875 static int 4876 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4877 const Elf_Vernaux *vna) 4878 { 4879 const Elf_Verdef *vd; 4880 const char *vername; 4881 4882 vername = refobj->strtab + vna->vna_name; 4883 vd = depobj->verdef; 4884 if (vd == NULL) { 4885 _rtld_error("%s: version %s required by %s not defined", 4886 depobj->path, vername, refobj->path); 4887 return (-1); 4888 } 4889 for (;;) { 4890 if (vd->vd_version != VER_DEF_CURRENT) { 4891 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4892 depobj->path, vd->vd_version); 4893 return (-1); 4894 } 4895 if (vna->vna_hash == vd->vd_hash) { 4896 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4897 ((char *)vd + vd->vd_aux); 4898 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4899 return (0); 4900 } 4901 if (vd->vd_next == 0) 4902 break; 4903 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4904 } 4905 if (vna->vna_flags & VER_FLG_WEAK) 4906 return (0); 4907 _rtld_error("%s: version %s required by %s not found", 4908 depobj->path, vername, refobj->path); 4909 return (-1); 4910 } 4911 4912 static int 4913 rtld_verify_object_versions(Obj_Entry *obj) 4914 { 4915 const Elf_Verneed *vn; 4916 const Elf_Verdef *vd; 4917 const Elf_Verdaux *vda; 4918 const Elf_Vernaux *vna; 4919 const Obj_Entry *depobj; 4920 int maxvernum, vernum; 4921 4922 if (obj->ver_checked) 4923 return (0); 4924 obj->ver_checked = true; 4925 4926 maxvernum = 0; 4927 /* 4928 * Walk over defined and required version records and figure out 4929 * max index used by any of them. Do very basic sanity checking 4930 * while there. 4931 */ 4932 vn = obj->verneed; 4933 while (vn != NULL) { 4934 if (vn->vn_version != VER_NEED_CURRENT) { 4935 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4936 obj->path, vn->vn_version); 4937 return (-1); 4938 } 4939 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4940 for (;;) { 4941 vernum = VER_NEED_IDX(vna->vna_other); 4942 if (vernum > maxvernum) 4943 maxvernum = vernum; 4944 if (vna->vna_next == 0) 4945 break; 4946 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4947 } 4948 if (vn->vn_next == 0) 4949 break; 4950 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4951 } 4952 4953 vd = obj->verdef; 4954 while (vd != NULL) { 4955 if (vd->vd_version != VER_DEF_CURRENT) { 4956 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4957 obj->path, vd->vd_version); 4958 return (-1); 4959 } 4960 vernum = VER_DEF_IDX(vd->vd_ndx); 4961 if (vernum > maxvernum) 4962 maxvernum = vernum; 4963 if (vd->vd_next == 0) 4964 break; 4965 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4966 } 4967 4968 if (maxvernum == 0) 4969 return (0); 4970 4971 /* 4972 * Store version information in array indexable by version index. 4973 * Verify that object version requirements are satisfied along the 4974 * way. 4975 */ 4976 obj->vernum = maxvernum + 1; 4977 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4978 4979 vd = obj->verdef; 4980 while (vd != NULL) { 4981 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4982 vernum = VER_DEF_IDX(vd->vd_ndx); 4983 assert(vernum <= maxvernum); 4984 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4985 obj->vertab[vernum].hash = vd->vd_hash; 4986 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4987 obj->vertab[vernum].file = NULL; 4988 obj->vertab[vernum].flags = 0; 4989 } 4990 if (vd->vd_next == 0) 4991 break; 4992 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4993 } 4994 4995 vn = obj->verneed; 4996 while (vn != NULL) { 4997 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4998 if (depobj == NULL) 4999 return (-1); 5000 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5001 for (;;) { 5002 if (check_object_provided_version(obj, depobj, vna)) 5003 return (-1); 5004 vernum = VER_NEED_IDX(vna->vna_other); 5005 assert(vernum <= maxvernum); 5006 obj->vertab[vernum].hash = vna->vna_hash; 5007 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5008 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5009 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5010 VER_INFO_HIDDEN : 0; 5011 if (vna->vna_next == 0) 5012 break; 5013 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5014 } 5015 if (vn->vn_next == 0) 5016 break; 5017 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5018 } 5019 return 0; 5020 } 5021 5022 static int 5023 rtld_verify_versions(const Objlist *objlist) 5024 { 5025 Objlist_Entry *entry; 5026 int rc; 5027 5028 rc = 0; 5029 STAILQ_FOREACH(entry, objlist, link) { 5030 /* 5031 * Skip dummy objects or objects that have their version requirements 5032 * already checked. 5033 */ 5034 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5035 continue; 5036 if (rtld_verify_object_versions(entry->obj) == -1) { 5037 rc = -1; 5038 if (ld_tracing == NULL) 5039 break; 5040 } 5041 } 5042 if (rc == 0 || ld_tracing != NULL) 5043 rc = rtld_verify_object_versions(&obj_rtld); 5044 return rc; 5045 } 5046 5047 const Ver_Entry * 5048 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5049 { 5050 Elf_Versym vernum; 5051 5052 if (obj->vertab) { 5053 vernum = VER_NDX(obj->versyms[symnum]); 5054 if (vernum >= obj->vernum) { 5055 _rtld_error("%s: symbol %s has wrong verneed value %d", 5056 obj->path, obj->strtab + symnum, vernum); 5057 } else if (obj->vertab[vernum].hash != 0) { 5058 return &obj->vertab[vernum]; 5059 } 5060 } 5061 return NULL; 5062 } 5063 5064 int 5065 _rtld_get_stack_prot(void) 5066 { 5067 5068 return (stack_prot); 5069 } 5070 5071 int 5072 _rtld_is_dlopened(void *arg) 5073 { 5074 Obj_Entry *obj; 5075 RtldLockState lockstate; 5076 int res; 5077 5078 rlock_acquire(rtld_bind_lock, &lockstate); 5079 obj = dlcheck(arg); 5080 if (obj == NULL) 5081 obj = obj_from_addr(arg); 5082 if (obj == NULL) { 5083 _rtld_error("No shared object contains address"); 5084 lock_release(rtld_bind_lock, &lockstate); 5085 return (-1); 5086 } 5087 res = obj->dlopened ? 1 : 0; 5088 lock_release(rtld_bind_lock, &lockstate); 5089 return (res); 5090 } 5091 5092 static void 5093 map_stacks_exec(RtldLockState *lockstate) 5094 { 5095 void (*thr_map_stacks_exec)(void); 5096 5097 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5098 return; 5099 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5100 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5101 if (thr_map_stacks_exec != NULL) { 5102 stack_prot |= PROT_EXEC; 5103 thr_map_stacks_exec(); 5104 } 5105 } 5106 5107 void 5108 symlook_init(SymLook *dst, const char *name) 5109 { 5110 5111 bzero(dst, sizeof(*dst)); 5112 dst->name = name; 5113 dst->hash = elf_hash(name); 5114 dst->hash_gnu = gnu_hash(name); 5115 } 5116 5117 static void 5118 symlook_init_from_req(SymLook *dst, const SymLook *src) 5119 { 5120 5121 dst->name = src->name; 5122 dst->hash = src->hash; 5123 dst->hash_gnu = src->hash_gnu; 5124 dst->ventry = src->ventry; 5125 dst->flags = src->flags; 5126 dst->defobj_out = NULL; 5127 dst->sym_out = NULL; 5128 dst->lockstate = src->lockstate; 5129 } 5130 5131 5132 /* 5133 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5134 */ 5135 static int 5136 parse_libdir(const char *str) 5137 { 5138 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5139 const char *orig; 5140 int fd; 5141 char c; 5142 5143 orig = str; 5144 fd = 0; 5145 for (c = *str; c != '\0'; c = *++str) { 5146 if (c < '0' || c > '9') 5147 return (-1); 5148 5149 fd *= RADIX; 5150 fd += c - '0'; 5151 } 5152 5153 /* Make sure we actually parsed something. */ 5154 if (str == orig) { 5155 _rtld_error("failed to parse directory FD from '%s'", str); 5156 return (-1); 5157 } 5158 return (fd); 5159 } 5160 5161 /* 5162 * Overrides for libc_pic-provided functions. 5163 */ 5164 5165 int 5166 __getosreldate(void) 5167 { 5168 size_t len; 5169 int oid[2]; 5170 int error, osrel; 5171 5172 if (osreldate != 0) 5173 return (osreldate); 5174 5175 oid[0] = CTL_KERN; 5176 oid[1] = KERN_OSRELDATE; 5177 osrel = 0; 5178 len = sizeof(osrel); 5179 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5180 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5181 osreldate = osrel; 5182 return (osreldate); 5183 } 5184 5185 void 5186 exit(int status) 5187 { 5188 5189 _exit(status); 5190 } 5191 5192 void (*__cleanup)(void); 5193 int __isthreaded = 0; 5194 int _thread_autoinit_dummy_decl = 1; 5195 5196 /* 5197 * No unresolved symbols for rtld. 5198 */ 5199 void 5200 __pthread_cxa_finalize(struct dl_phdr_info *a) 5201 { 5202 } 5203 5204 void 5205 __stack_chk_fail(void) 5206 { 5207 5208 _rtld_error("stack overflow detected; terminated"); 5209 rtld_die(); 5210 } 5211 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5212 5213 void 5214 __chk_fail(void) 5215 { 5216 5217 _rtld_error("buffer overflow detected; terminated"); 5218 rtld_die(); 5219 } 5220 5221 const char * 5222 rtld_strerror(int errnum) 5223 { 5224 5225 if (errnum < 0 || errnum >= sys_nerr) 5226 return ("Unknown error"); 5227 return (sys_errlist[errnum]); 5228 } 5229