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] != 0) { 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 occurences, 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 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 unsigned int SLPndx, hintndx, fndx, fcount; 1676 int fd; 1677 size_t flen; 1678 bool skip; 1679 1680 /* First call, read the hints file */ 1681 if (hints == NULL) { 1682 /* Keep from trying again in case the hints file is bad. */ 1683 hints = ""; 1684 1685 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1686 return (NULL); 1687 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1688 hdr.magic != ELFHINTS_MAGIC || 1689 hdr.version != 1) { 1690 close(fd); 1691 return (NULL); 1692 } 1693 p = xmalloc(hdr.dirlistlen + 1); 1694 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1695 read(fd, p, hdr.dirlistlen + 1) != 1696 (ssize_t)hdr.dirlistlen + 1) { 1697 free(p); 1698 close(fd); 1699 return (NULL); 1700 } 1701 hints = p; 1702 close(fd); 1703 } 1704 1705 /* 1706 * If caller agreed to receive list which includes the default 1707 * paths, we are done. Otherwise, if we still did not 1708 * calculated filtered result, do it now. 1709 */ 1710 if (!nostdlib) 1711 return (hints[0] != '\0' ? hints : NULL); 1712 if (filtered_path != NULL) 1713 goto filt_ret; 1714 1715 /* 1716 * Obtain the list of all configured search paths, and the 1717 * list of the default paths. 1718 * 1719 * First estimate the size of the results. 1720 */ 1721 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1722 smeta.dls_cnt = 0; 1723 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1724 hmeta.dls_cnt = 0; 1725 1726 sargs.request = RTLD_DI_SERINFOSIZE; 1727 sargs.serinfo = &smeta; 1728 hargs.request = RTLD_DI_SERINFOSIZE; 1729 hargs.serinfo = &hmeta; 1730 1731 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1732 path_enumerate(p, fill_search_info, &hargs); 1733 1734 SLPinfo = xmalloc(smeta.dls_size); 1735 hintinfo = xmalloc(hmeta.dls_size); 1736 1737 /* 1738 * Next fetch both sets of paths. 1739 */ 1740 sargs.request = RTLD_DI_SERINFO; 1741 sargs.serinfo = SLPinfo; 1742 sargs.serpath = &SLPinfo->dls_serpath[0]; 1743 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1744 1745 hargs.request = RTLD_DI_SERINFO; 1746 hargs.serinfo = hintinfo; 1747 hargs.serpath = &hintinfo->dls_serpath[0]; 1748 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1749 1750 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1751 path_enumerate(p, fill_search_info, &hargs); 1752 1753 /* 1754 * Now calculate the difference between two sets, by excluding 1755 * standard paths from the full set. 1756 */ 1757 fndx = 0; 1758 fcount = 0; 1759 filtered_path = xmalloc(hdr.dirlistlen + 1); 1760 hintpath = &hintinfo->dls_serpath[0]; 1761 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1762 skip = false; 1763 SLPpath = &SLPinfo->dls_serpath[0]; 1764 /* 1765 * Check each standard path against current. 1766 */ 1767 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1768 /* matched, skip the path */ 1769 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1770 skip = true; 1771 break; 1772 } 1773 } 1774 if (skip) 1775 continue; 1776 /* 1777 * Not matched against any standard path, add the path 1778 * to result. Separate consequtive paths with ':'. 1779 */ 1780 if (fcount > 0) { 1781 filtered_path[fndx] = ':'; 1782 fndx++; 1783 } 1784 fcount++; 1785 flen = strlen(hintpath->dls_name); 1786 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1787 fndx += flen; 1788 } 1789 filtered_path[fndx] = '\0'; 1790 1791 free(SLPinfo); 1792 free(hintinfo); 1793 1794 filt_ret: 1795 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1796 } 1797 1798 static void 1799 init_dag(Obj_Entry *root) 1800 { 1801 const Needed_Entry *needed; 1802 const Objlist_Entry *elm; 1803 DoneList donelist; 1804 1805 if (root->dag_inited) 1806 return; 1807 donelist_init(&donelist); 1808 1809 /* Root object belongs to own DAG. */ 1810 objlist_push_tail(&root->dldags, root); 1811 objlist_push_tail(&root->dagmembers, root); 1812 donelist_check(&donelist, root); 1813 1814 /* 1815 * Add dependencies of root object to DAG in breadth order 1816 * by exploiting the fact that each new object get added 1817 * to the tail of the dagmembers list. 1818 */ 1819 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1820 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1821 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1822 continue; 1823 objlist_push_tail(&needed->obj->dldags, root); 1824 objlist_push_tail(&root->dagmembers, needed->obj); 1825 } 1826 } 1827 root->dag_inited = true; 1828 } 1829 1830 Obj_Entry * 1831 globallist_curr(const Obj_Entry *obj) 1832 { 1833 1834 for (;;) { 1835 if (obj == NULL) 1836 return (NULL); 1837 if (!obj->marker) 1838 return (__DECONST(Obj_Entry *, obj)); 1839 obj = TAILQ_PREV(obj, obj_entry_q, next); 1840 } 1841 } 1842 1843 Obj_Entry * 1844 globallist_next(const Obj_Entry *obj) 1845 { 1846 1847 for (;;) { 1848 obj = TAILQ_NEXT(obj, next); 1849 if (obj == NULL) 1850 return (NULL); 1851 if (!obj->marker) 1852 return (__DECONST(Obj_Entry *, obj)); 1853 } 1854 } 1855 1856 static void 1857 process_z(Obj_Entry *root) 1858 { 1859 const Objlist_Entry *elm; 1860 Obj_Entry *obj; 1861 1862 /* 1863 * Walk over object DAG and process every dependent object 1864 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1865 * to grow their own DAG. 1866 * 1867 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1868 * symlook_global() to work. 1869 * 1870 * For DF_1_NODELETE, the DAG should have its reference upped. 1871 */ 1872 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1873 obj = elm->obj; 1874 if (obj == NULL) 1875 continue; 1876 if (obj->z_nodelete && !obj->ref_nodel) { 1877 dbg("obj %s -z nodelete", obj->path); 1878 init_dag(obj); 1879 ref_dag(obj); 1880 obj->ref_nodel = true; 1881 } 1882 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1883 dbg("obj %s -z global", obj->path); 1884 objlist_push_tail(&list_global, obj); 1885 init_dag(obj); 1886 } 1887 } 1888 } 1889 /* 1890 * Initialize the dynamic linker. The argument is the address at which 1891 * the dynamic linker has been mapped into memory. The primary task of 1892 * this function is to relocate the dynamic linker. 1893 */ 1894 static void 1895 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1896 { 1897 Obj_Entry objtmp; /* Temporary rtld object */ 1898 const Elf_Dyn *dyn_rpath; 1899 const Elf_Dyn *dyn_soname; 1900 const Elf_Dyn *dyn_runpath; 1901 1902 #ifdef RTLD_INIT_PAGESIZES_EARLY 1903 /* The page size is required by the dynamic memory allocator. */ 1904 init_pagesizes(aux_info); 1905 #endif 1906 1907 /* 1908 * Conjure up an Obj_Entry structure for the dynamic linker. 1909 * 1910 * The "path" member can't be initialized yet because string constants 1911 * cannot yet be accessed. Below we will set it correctly. 1912 */ 1913 memset(&objtmp, 0, sizeof(objtmp)); 1914 objtmp.path = NULL; 1915 objtmp.rtld = true; 1916 objtmp.mapbase = mapbase; 1917 #ifdef PIC 1918 objtmp.relocbase = mapbase; 1919 #endif 1920 if (RTLD_IS_DYNAMIC()) { 1921 objtmp.dynamic = rtld_dynamic(&objtmp); 1922 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1923 assert(objtmp.needed == NULL); 1924 #if !defined(__mips__) 1925 /* MIPS has a bogus DT_TEXTREL. */ 1926 assert(!objtmp.textrel); 1927 #endif 1928 1929 /* 1930 * Temporarily put the dynamic linker entry into the object list, so 1931 * that symbols can be found. 1932 */ 1933 1934 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1935 } 1936 1937 /* Initialize the object list. */ 1938 TAILQ_INIT(&obj_list); 1939 1940 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1941 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1942 1943 #ifndef RTLD_INIT_PAGESIZES_EARLY 1944 /* The page size is required by the dynamic memory allocator. */ 1945 init_pagesizes(aux_info); 1946 #endif 1947 1948 if (aux_info[AT_OSRELDATE] != NULL) 1949 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1950 1951 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1952 1953 /* Replace the path with a dynamically allocated copy. */ 1954 obj_rtld.path = xstrdup(ld_path_rtld); 1955 1956 r_debug.r_brk = r_debug_state; 1957 r_debug.r_state = RT_CONSISTENT; 1958 } 1959 1960 /* 1961 * Retrieve the array of supported page sizes. The kernel provides the page 1962 * sizes in increasing order. 1963 */ 1964 static void 1965 init_pagesizes(Elf_Auxinfo **aux_info) 1966 { 1967 static size_t psa[MAXPAGESIZES]; 1968 int mib[2]; 1969 size_t len, size; 1970 1971 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1972 NULL) { 1973 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1974 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1975 } else { 1976 len = 2; 1977 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1978 size = sizeof(psa); 1979 else { 1980 /* As a fallback, retrieve the base page size. */ 1981 size = sizeof(psa[0]); 1982 if (aux_info[AT_PAGESZ] != NULL) { 1983 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1984 goto psa_filled; 1985 } else { 1986 mib[0] = CTL_HW; 1987 mib[1] = HW_PAGESIZE; 1988 len = 2; 1989 } 1990 } 1991 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1992 _rtld_error("sysctl for hw.pagesize(s) failed"); 1993 rtld_die(); 1994 } 1995 psa_filled: 1996 pagesizes = psa; 1997 } 1998 npagesizes = size / sizeof(pagesizes[0]); 1999 /* Discard any invalid entries at the end of the array. */ 2000 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2001 npagesizes--; 2002 } 2003 2004 /* 2005 * Add the init functions from a needed object list (and its recursive 2006 * needed objects) to "list". This is not used directly; it is a helper 2007 * function for initlist_add_objects(). The write lock must be held 2008 * when this function is called. 2009 */ 2010 static void 2011 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2012 { 2013 /* Recursively process the successor needed objects. */ 2014 if (needed->next != NULL) 2015 initlist_add_neededs(needed->next, list); 2016 2017 /* Process the current needed object. */ 2018 if (needed->obj != NULL) 2019 initlist_add_objects(needed->obj, needed->obj, list); 2020 } 2021 2022 /* 2023 * Scan all of the DAGs rooted in the range of objects from "obj" to 2024 * "tail" and add their init functions to "list". This recurses over 2025 * the DAGs and ensure the proper init ordering such that each object's 2026 * needed libraries are initialized before the object itself. At the 2027 * same time, this function adds the objects to the global finalization 2028 * list "list_fini" in the opposite order. The write lock must be 2029 * held when this function is called. 2030 */ 2031 static void 2032 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2033 { 2034 Obj_Entry *nobj; 2035 2036 if (obj->init_scanned || obj->init_done) 2037 return; 2038 obj->init_scanned = true; 2039 2040 /* Recursively process the successor objects. */ 2041 nobj = globallist_next(obj); 2042 if (nobj != NULL && obj != tail) 2043 initlist_add_objects(nobj, tail, list); 2044 2045 /* Recursively process the needed objects. */ 2046 if (obj->needed != NULL) 2047 initlist_add_neededs(obj->needed, list); 2048 if (obj->needed_filtees != NULL) 2049 initlist_add_neededs(obj->needed_filtees, list); 2050 if (obj->needed_aux_filtees != NULL) 2051 initlist_add_neededs(obj->needed_aux_filtees, list); 2052 2053 /* Add the object to the init list. */ 2054 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2055 obj->init_array != (Elf_Addr)NULL) 2056 objlist_push_tail(list, obj); 2057 2058 /* Add the object to the global fini list in the reverse order. */ 2059 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2060 && !obj->on_fini_list) { 2061 objlist_push_head(&list_fini, obj); 2062 obj->on_fini_list = true; 2063 } 2064 } 2065 2066 #ifndef FPTR_TARGET 2067 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2068 #endif 2069 2070 static void 2071 free_needed_filtees(Needed_Entry *n) 2072 { 2073 Needed_Entry *needed, *needed1; 2074 2075 for (needed = n; needed != NULL; needed = needed->next) { 2076 if (needed->obj != NULL) { 2077 dlclose(needed->obj); 2078 needed->obj = NULL; 2079 } 2080 } 2081 for (needed = n; needed != NULL; needed = needed1) { 2082 needed1 = needed->next; 2083 free(needed); 2084 } 2085 } 2086 2087 static void 2088 unload_filtees(Obj_Entry *obj) 2089 { 2090 2091 free_needed_filtees(obj->needed_filtees); 2092 obj->needed_filtees = NULL; 2093 free_needed_filtees(obj->needed_aux_filtees); 2094 obj->needed_aux_filtees = NULL; 2095 obj->filtees_loaded = false; 2096 } 2097 2098 static void 2099 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2100 RtldLockState *lockstate) 2101 { 2102 2103 for (; needed != NULL; needed = needed->next) { 2104 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2105 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2106 RTLD_LOCAL, lockstate); 2107 } 2108 } 2109 2110 static void 2111 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2112 { 2113 2114 lock_restart_for_upgrade(lockstate); 2115 if (!obj->filtees_loaded) { 2116 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2117 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2118 obj->filtees_loaded = true; 2119 } 2120 } 2121 2122 static int 2123 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2124 { 2125 Obj_Entry *obj1; 2126 2127 for (; needed != NULL; needed = needed->next) { 2128 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2129 flags & ~RTLD_LO_NOLOAD); 2130 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2131 return (-1); 2132 } 2133 return (0); 2134 } 2135 2136 /* 2137 * Given a shared object, traverse its list of needed objects, and load 2138 * each of them. Returns 0 on success. Generates an error message and 2139 * returns -1 on failure. 2140 */ 2141 static int 2142 load_needed_objects(Obj_Entry *first, int flags) 2143 { 2144 Obj_Entry *obj; 2145 2146 obj = first; 2147 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2148 if (obj->marker) 2149 continue; 2150 if (process_needed(obj, obj->needed, flags) == -1) 2151 return (-1); 2152 } 2153 return (0); 2154 } 2155 2156 static int 2157 load_preload_objects(void) 2158 { 2159 char *p = ld_preload; 2160 Obj_Entry *obj; 2161 static const char delim[] = " \t:;"; 2162 2163 if (p == NULL) 2164 return 0; 2165 2166 p += strspn(p, delim); 2167 while (*p != '\0') { 2168 size_t len = strcspn(p, delim); 2169 char savech; 2170 2171 savech = p[len]; 2172 p[len] = '\0'; 2173 obj = load_object(p, -1, NULL, 0); 2174 if (obj == NULL) 2175 return -1; /* XXX - cleanup */ 2176 obj->z_interpose = true; 2177 p[len] = savech; 2178 p += len; 2179 p += strspn(p, delim); 2180 } 2181 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2182 return 0; 2183 } 2184 2185 static const char * 2186 printable_path(const char *path) 2187 { 2188 2189 return (path == NULL ? "<unknown>" : path); 2190 } 2191 2192 /* 2193 * Load a shared object into memory, if it is not already loaded. The 2194 * object may be specified by name or by user-supplied file descriptor 2195 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2196 * duplicate is. 2197 * 2198 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2199 * on failure. 2200 */ 2201 static Obj_Entry * 2202 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2203 { 2204 Obj_Entry *obj; 2205 int fd; 2206 struct stat sb; 2207 char *path; 2208 2209 fd = -1; 2210 if (name != NULL) { 2211 TAILQ_FOREACH(obj, &obj_list, next) { 2212 if (obj->marker) 2213 continue; 2214 if (object_match_name(obj, name)) 2215 return (obj); 2216 } 2217 2218 path = find_library(name, refobj, &fd); 2219 if (path == NULL) 2220 return (NULL); 2221 } else 2222 path = NULL; 2223 2224 if (fd >= 0) { 2225 /* 2226 * search_library_pathfds() opens a fresh file descriptor for the 2227 * library, so there is no need to dup(). 2228 */ 2229 } else if (fd_u == -1) { 2230 /* 2231 * If we didn't find a match by pathname, or the name is not 2232 * supplied, open the file and check again by device and inode. 2233 * This avoids false mismatches caused by multiple links or ".." 2234 * in pathnames. 2235 * 2236 * To avoid a race, we open the file and use fstat() rather than 2237 * using stat(). 2238 */ 2239 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2240 _rtld_error("Cannot open \"%s\"", path); 2241 free(path); 2242 return (NULL); 2243 } 2244 } else { 2245 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2246 if (fd == -1) { 2247 _rtld_error("Cannot dup fd"); 2248 free(path); 2249 return (NULL); 2250 } 2251 } 2252 if (fstat(fd, &sb) == -1) { 2253 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2254 close(fd); 2255 free(path); 2256 return NULL; 2257 } 2258 TAILQ_FOREACH(obj, &obj_list, next) { 2259 if (obj->marker) 2260 continue; 2261 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2262 break; 2263 } 2264 if (obj != NULL && name != NULL) { 2265 object_add_name(obj, name); 2266 free(path); 2267 close(fd); 2268 return obj; 2269 } 2270 if (flags & RTLD_LO_NOLOAD) { 2271 free(path); 2272 close(fd); 2273 return (NULL); 2274 } 2275 2276 /* First use of this object, so we must map it in */ 2277 obj = do_load_object(fd, name, path, &sb, flags); 2278 if (obj == NULL) 2279 free(path); 2280 close(fd); 2281 2282 return obj; 2283 } 2284 2285 static Obj_Entry * 2286 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2287 int flags) 2288 { 2289 Obj_Entry *obj; 2290 struct statfs fs; 2291 2292 /* 2293 * but first, make sure that environment variables haven't been 2294 * used to circumvent the noexec flag on a filesystem. 2295 */ 2296 if (dangerous_ld_env) { 2297 if (fstatfs(fd, &fs) != 0) { 2298 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2299 return NULL; 2300 } 2301 if (fs.f_flags & MNT_NOEXEC) { 2302 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2303 return NULL; 2304 } 2305 } 2306 dbg("loading \"%s\"", printable_path(path)); 2307 obj = map_object(fd, printable_path(path), sbp); 2308 if (obj == NULL) 2309 return NULL; 2310 2311 /* 2312 * If DT_SONAME is present in the object, digest_dynamic2 already 2313 * added it to the object names. 2314 */ 2315 if (name != NULL) 2316 object_add_name(obj, name); 2317 obj->path = path; 2318 digest_dynamic(obj, 0); 2319 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2320 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2321 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2322 RTLD_LO_DLOPEN) { 2323 dbg("refusing to load non-loadable \"%s\"", obj->path); 2324 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2325 munmap(obj->mapbase, obj->mapsize); 2326 obj_free(obj); 2327 return (NULL); 2328 } 2329 2330 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2331 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2332 obj_count++; 2333 obj_loads++; 2334 linkmap_add(obj); /* for GDB & dlinfo() */ 2335 max_stack_flags |= obj->stack_flags; 2336 2337 dbg(" %p .. %p: %s", obj->mapbase, 2338 obj->mapbase + obj->mapsize - 1, obj->path); 2339 if (obj->textrel) 2340 dbg(" WARNING: %s has impure text", obj->path); 2341 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2342 obj->path); 2343 2344 return obj; 2345 } 2346 2347 static Obj_Entry * 2348 obj_from_addr(const void *addr) 2349 { 2350 Obj_Entry *obj; 2351 2352 TAILQ_FOREACH(obj, &obj_list, next) { 2353 if (obj->marker) 2354 continue; 2355 if (addr < (void *) obj->mapbase) 2356 continue; 2357 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2358 return obj; 2359 } 2360 return NULL; 2361 } 2362 2363 static void 2364 preinit_main(void) 2365 { 2366 Elf_Addr *preinit_addr; 2367 int index; 2368 2369 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2370 if (preinit_addr == NULL) 2371 return; 2372 2373 for (index = 0; index < obj_main->preinit_array_num; index++) { 2374 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2375 dbg("calling preinit function for %s at %p", obj_main->path, 2376 (void *)preinit_addr[index]); 2377 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2378 0, 0, obj_main->path); 2379 call_init_pointer(obj_main, preinit_addr[index]); 2380 } 2381 } 2382 } 2383 2384 /* 2385 * Call the finalization functions for each of the objects in "list" 2386 * belonging to the DAG of "root" and referenced once. If NULL "root" 2387 * is specified, every finalization function will be called regardless 2388 * of the reference count and the list elements won't be freed. All of 2389 * the objects are expected to have non-NULL fini functions. 2390 */ 2391 static void 2392 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2393 { 2394 Objlist_Entry *elm; 2395 char *saved_msg; 2396 Elf_Addr *fini_addr; 2397 int index; 2398 2399 assert(root == NULL || root->refcount == 1); 2400 2401 /* 2402 * Preserve the current error message since a fini function might 2403 * call into the dynamic linker and overwrite it. 2404 */ 2405 saved_msg = errmsg_save(); 2406 do { 2407 STAILQ_FOREACH(elm, list, link) { 2408 if (root != NULL && (elm->obj->refcount != 1 || 2409 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2410 continue; 2411 /* Remove object from fini list to prevent recursive invocation. */ 2412 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2413 /* 2414 * XXX: If a dlopen() call references an object while the 2415 * fini function is in progress, we might end up trying to 2416 * unload the referenced object in dlclose() or the object 2417 * won't be unloaded although its fini function has been 2418 * called. 2419 */ 2420 lock_release(rtld_bind_lock, lockstate); 2421 2422 /* 2423 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2424 * When this happens, DT_FINI_ARRAY is processed first. 2425 */ 2426 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2427 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2428 for (index = elm->obj->fini_array_num - 1; index >= 0; 2429 index--) { 2430 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2431 dbg("calling fini function for %s at %p", 2432 elm->obj->path, (void *)fini_addr[index]); 2433 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2434 (void *)fini_addr[index], 0, 0, elm->obj->path); 2435 call_initfini_pointer(elm->obj, fini_addr[index]); 2436 } 2437 } 2438 } 2439 if (elm->obj->fini != (Elf_Addr)NULL) { 2440 dbg("calling fini function for %s at %p", elm->obj->path, 2441 (void *)elm->obj->fini); 2442 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2443 0, 0, elm->obj->path); 2444 call_initfini_pointer(elm->obj, elm->obj->fini); 2445 } 2446 wlock_acquire(rtld_bind_lock, lockstate); 2447 /* No need to free anything if process is going down. */ 2448 if (root != NULL) 2449 free(elm); 2450 /* 2451 * We must restart the list traversal after every fini call 2452 * because a dlclose() call from the fini function or from 2453 * another thread might have modified the reference counts. 2454 */ 2455 break; 2456 } 2457 } while (elm != NULL); 2458 errmsg_restore(saved_msg); 2459 } 2460 2461 /* 2462 * Call the initialization functions for each of the objects in 2463 * "list". All of the objects are expected to have non-NULL init 2464 * functions. 2465 */ 2466 static void 2467 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2468 { 2469 Objlist_Entry *elm; 2470 Obj_Entry *obj; 2471 char *saved_msg; 2472 Elf_Addr *init_addr; 2473 int index; 2474 2475 /* 2476 * Clean init_scanned flag so that objects can be rechecked and 2477 * possibly initialized earlier if any of vectors called below 2478 * cause the change by using dlopen. 2479 */ 2480 TAILQ_FOREACH(obj, &obj_list, next) { 2481 if (obj->marker) 2482 continue; 2483 obj->init_scanned = false; 2484 } 2485 2486 /* 2487 * Preserve the current error message since an init function might 2488 * call into the dynamic linker and overwrite it. 2489 */ 2490 saved_msg = errmsg_save(); 2491 STAILQ_FOREACH(elm, list, link) { 2492 if (elm->obj->init_done) /* Initialized early. */ 2493 continue; 2494 /* 2495 * Race: other thread might try to use this object before current 2496 * one completes the initilization. Not much can be done here 2497 * without better locking. 2498 */ 2499 elm->obj->init_done = true; 2500 lock_release(rtld_bind_lock, lockstate); 2501 2502 /* 2503 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2504 * When this happens, DT_INIT is processed first. 2505 */ 2506 if (elm->obj->init != (Elf_Addr)NULL) { 2507 dbg("calling init function for %s at %p", elm->obj->path, 2508 (void *)elm->obj->init); 2509 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2510 0, 0, elm->obj->path); 2511 call_initfini_pointer(elm->obj, elm->obj->init); 2512 } 2513 init_addr = (Elf_Addr *)elm->obj->init_array; 2514 if (init_addr != NULL) { 2515 for (index = 0; index < elm->obj->init_array_num; index++) { 2516 if (init_addr[index] != 0 && init_addr[index] != 1) { 2517 dbg("calling init function for %s at %p", elm->obj->path, 2518 (void *)init_addr[index]); 2519 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2520 (void *)init_addr[index], 0, 0, elm->obj->path); 2521 call_init_pointer(elm->obj, init_addr[index]); 2522 } 2523 } 2524 } 2525 wlock_acquire(rtld_bind_lock, lockstate); 2526 } 2527 errmsg_restore(saved_msg); 2528 } 2529 2530 static void 2531 objlist_clear(Objlist *list) 2532 { 2533 Objlist_Entry *elm; 2534 2535 while (!STAILQ_EMPTY(list)) { 2536 elm = STAILQ_FIRST(list); 2537 STAILQ_REMOVE_HEAD(list, link); 2538 free(elm); 2539 } 2540 } 2541 2542 static Objlist_Entry * 2543 objlist_find(Objlist *list, const Obj_Entry *obj) 2544 { 2545 Objlist_Entry *elm; 2546 2547 STAILQ_FOREACH(elm, list, link) 2548 if (elm->obj == obj) 2549 return elm; 2550 return NULL; 2551 } 2552 2553 static void 2554 objlist_init(Objlist *list) 2555 { 2556 STAILQ_INIT(list); 2557 } 2558 2559 static void 2560 objlist_push_head(Objlist *list, Obj_Entry *obj) 2561 { 2562 Objlist_Entry *elm; 2563 2564 elm = NEW(Objlist_Entry); 2565 elm->obj = obj; 2566 STAILQ_INSERT_HEAD(list, elm, link); 2567 } 2568 2569 static void 2570 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2571 { 2572 Objlist_Entry *elm; 2573 2574 elm = NEW(Objlist_Entry); 2575 elm->obj = obj; 2576 STAILQ_INSERT_TAIL(list, elm, link); 2577 } 2578 2579 static void 2580 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2581 { 2582 Objlist_Entry *elm, *listelm; 2583 2584 STAILQ_FOREACH(listelm, list, link) { 2585 if (listelm->obj == listobj) 2586 break; 2587 } 2588 elm = NEW(Objlist_Entry); 2589 elm->obj = obj; 2590 if (listelm != NULL) 2591 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2592 else 2593 STAILQ_INSERT_TAIL(list, elm, link); 2594 } 2595 2596 static void 2597 objlist_remove(Objlist *list, Obj_Entry *obj) 2598 { 2599 Objlist_Entry *elm; 2600 2601 if ((elm = objlist_find(list, obj)) != NULL) { 2602 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2603 free(elm); 2604 } 2605 } 2606 2607 /* 2608 * Relocate dag rooted in the specified object. 2609 * Returns 0 on success, or -1 on failure. 2610 */ 2611 2612 static int 2613 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2614 int flags, RtldLockState *lockstate) 2615 { 2616 Objlist_Entry *elm; 2617 int error; 2618 2619 error = 0; 2620 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2621 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2622 lockstate); 2623 if (error == -1) 2624 break; 2625 } 2626 return (error); 2627 } 2628 2629 /* 2630 * Relocate single object. 2631 * Returns 0 on success, or -1 on failure. 2632 */ 2633 static int 2634 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2635 int flags, RtldLockState *lockstate) 2636 { 2637 2638 if (obj->relocated) 2639 return (0); 2640 obj->relocated = true; 2641 if (obj != rtldobj) 2642 dbg("relocating \"%s\"", obj->path); 2643 2644 if (obj->symtab == NULL || obj->strtab == NULL || 2645 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2646 _rtld_error("%s: Shared object has no run-time symbol table", 2647 obj->path); 2648 return (-1); 2649 } 2650 2651 if (obj->textrel) { 2652 /* There are relocations to the write-protected text segment. */ 2653 if (mprotect(obj->mapbase, obj->textsize, 2654 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2655 _rtld_error("%s: Cannot write-enable text segment: %s", 2656 obj->path, rtld_strerror(errno)); 2657 return (-1); 2658 } 2659 } 2660 2661 /* Process the non-PLT non-IFUNC relocations. */ 2662 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2663 return (-1); 2664 2665 if (obj->textrel) { /* Re-protected the text segment. */ 2666 if (mprotect(obj->mapbase, obj->textsize, 2667 PROT_READ|PROT_EXEC) == -1) { 2668 _rtld_error("%s: Cannot write-protect text segment: %s", 2669 obj->path, rtld_strerror(errno)); 2670 return (-1); 2671 } 2672 } 2673 2674 /* Set the special PLT or GOT entries. */ 2675 init_pltgot(obj); 2676 2677 /* Process the PLT relocations. */ 2678 if (reloc_plt(obj) == -1) 2679 return (-1); 2680 /* Relocate the jump slots if we are doing immediate binding. */ 2681 if (obj->bind_now || bind_now) 2682 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2683 return (-1); 2684 2685 /* 2686 * Process the non-PLT IFUNC relocations. The relocations are 2687 * processed in two phases, because IFUNC resolvers may 2688 * reference other symbols, which must be readily processed 2689 * before resolvers are called. 2690 */ 2691 if (obj->non_plt_gnu_ifunc && 2692 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2693 return (-1); 2694 2695 if (obj->relro_size > 0) { 2696 if (mprotect(obj->relro_page, obj->relro_size, 2697 PROT_READ) == -1) { 2698 _rtld_error("%s: Cannot enforce relro protection: %s", 2699 obj->path, rtld_strerror(errno)); 2700 return (-1); 2701 } 2702 } 2703 2704 /* 2705 * Set up the magic number and version in the Obj_Entry. These 2706 * were checked in the crt1.o from the original ElfKit, so we 2707 * set them for backward compatibility. 2708 */ 2709 obj->magic = RTLD_MAGIC; 2710 obj->version = RTLD_VERSION; 2711 2712 return (0); 2713 } 2714 2715 /* 2716 * Relocate newly-loaded shared objects. The argument is a pointer to 2717 * the Obj_Entry for the first such object. All objects from the first 2718 * to the end of the list of objects are relocated. Returns 0 on success, 2719 * or -1 on failure. 2720 */ 2721 static int 2722 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2723 int flags, RtldLockState *lockstate) 2724 { 2725 Obj_Entry *obj; 2726 int error; 2727 2728 error = 0; 2729 obj = first; 2730 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2731 if (obj->marker) 2732 continue; 2733 error = relocate_object(obj, bind_now, rtldobj, flags, 2734 lockstate); 2735 if (error == -1) 2736 break; 2737 } 2738 return (error); 2739 } 2740 2741 /* 2742 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2743 * referencing STT_GNU_IFUNC symbols is postponed till the other 2744 * relocations are done. The indirect functions specified as 2745 * ifunc are allowed to call other symbols, so we need to have 2746 * objects relocated before asking for resolution from indirects. 2747 * 2748 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2749 * instead of the usual lazy handling of PLT slots. It is 2750 * consistent with how GNU does it. 2751 */ 2752 static int 2753 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2754 RtldLockState *lockstate) 2755 { 2756 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2757 return (-1); 2758 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2759 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2760 return (-1); 2761 return (0); 2762 } 2763 2764 static int 2765 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2766 RtldLockState *lockstate) 2767 { 2768 Obj_Entry *obj; 2769 2770 obj = first; 2771 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2772 if (obj->marker) 2773 continue; 2774 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2775 return (-1); 2776 } 2777 return (0); 2778 } 2779 2780 static int 2781 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2782 RtldLockState *lockstate) 2783 { 2784 Objlist_Entry *elm; 2785 2786 STAILQ_FOREACH(elm, list, link) { 2787 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2788 lockstate) == -1) 2789 return (-1); 2790 } 2791 return (0); 2792 } 2793 2794 /* 2795 * Cleanup procedure. It will be called (by the atexit mechanism) just 2796 * before the process exits. 2797 */ 2798 static void 2799 rtld_exit(void) 2800 { 2801 RtldLockState lockstate; 2802 2803 wlock_acquire(rtld_bind_lock, &lockstate); 2804 dbg("rtld_exit()"); 2805 objlist_call_fini(&list_fini, NULL, &lockstate); 2806 /* No need to remove the items from the list, since we are exiting. */ 2807 if (!libmap_disable) 2808 lm_fini(); 2809 lock_release(rtld_bind_lock, &lockstate); 2810 } 2811 2812 /* 2813 * Iterate over a search path, translate each element, and invoke the 2814 * callback on the result. 2815 */ 2816 static void * 2817 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2818 { 2819 const char *trans; 2820 if (path == NULL) 2821 return (NULL); 2822 2823 path += strspn(path, ":;"); 2824 while (*path != '\0') { 2825 size_t len; 2826 char *res; 2827 2828 len = strcspn(path, ":;"); 2829 trans = lm_findn(NULL, path, len); 2830 if (trans) 2831 res = callback(trans, strlen(trans), arg); 2832 else 2833 res = callback(path, len, arg); 2834 2835 if (res != NULL) 2836 return (res); 2837 2838 path += len; 2839 path += strspn(path, ":;"); 2840 } 2841 2842 return (NULL); 2843 } 2844 2845 struct try_library_args { 2846 const char *name; 2847 size_t namelen; 2848 char *buffer; 2849 size_t buflen; 2850 }; 2851 2852 static void * 2853 try_library_path(const char *dir, size_t dirlen, void *param) 2854 { 2855 struct try_library_args *arg; 2856 2857 arg = param; 2858 if (*dir == '/' || trust) { 2859 char *pathname; 2860 2861 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2862 return (NULL); 2863 2864 pathname = arg->buffer; 2865 strncpy(pathname, dir, dirlen); 2866 pathname[dirlen] = '/'; 2867 strcpy(pathname + dirlen + 1, arg->name); 2868 2869 dbg(" Trying \"%s\"", pathname); 2870 if (access(pathname, F_OK) == 0) { /* We found it */ 2871 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2872 strcpy(pathname, arg->buffer); 2873 return (pathname); 2874 } 2875 } 2876 return (NULL); 2877 } 2878 2879 static char * 2880 search_library_path(const char *name, const char *path) 2881 { 2882 char *p; 2883 struct try_library_args arg; 2884 2885 if (path == NULL) 2886 return NULL; 2887 2888 arg.name = name; 2889 arg.namelen = strlen(name); 2890 arg.buffer = xmalloc(PATH_MAX); 2891 arg.buflen = PATH_MAX; 2892 2893 p = path_enumerate(path, try_library_path, &arg); 2894 2895 free(arg.buffer); 2896 2897 return (p); 2898 } 2899 2900 2901 /* 2902 * Finds the library with the given name using the directory descriptors 2903 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2904 * 2905 * Returns a freshly-opened close-on-exec file descriptor for the library, 2906 * or -1 if the library cannot be found. 2907 */ 2908 static char * 2909 search_library_pathfds(const char *name, const char *path, int *fdp) 2910 { 2911 char *envcopy, *fdstr, *found, *last_token; 2912 size_t len; 2913 int dirfd, fd; 2914 2915 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2916 2917 /* Don't load from user-specified libdirs into setuid binaries. */ 2918 if (!trust) 2919 return (NULL); 2920 2921 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2922 if (path == NULL) 2923 return (NULL); 2924 2925 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2926 if (name[0] == '/') { 2927 dbg("Absolute path (%s) passed to %s", name, __func__); 2928 return (NULL); 2929 } 2930 2931 /* 2932 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2933 * copy of the path, as strtok_r rewrites separator tokens 2934 * with '\0'. 2935 */ 2936 found = NULL; 2937 envcopy = xstrdup(path); 2938 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2939 fdstr = strtok_r(NULL, ":", &last_token)) { 2940 dirfd = parse_libdir(fdstr); 2941 if (dirfd < 0) 2942 break; 2943 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2944 if (fd >= 0) { 2945 *fdp = fd; 2946 len = strlen(fdstr) + strlen(name) + 3; 2947 found = xmalloc(len); 2948 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2949 _rtld_error("error generating '%d/%s'", 2950 dirfd, name); 2951 rtld_die(); 2952 } 2953 dbg("open('%s') => %d", found, fd); 2954 break; 2955 } 2956 } 2957 free(envcopy); 2958 2959 return (found); 2960 } 2961 2962 2963 int 2964 dlclose(void *handle) 2965 { 2966 Obj_Entry *root; 2967 RtldLockState lockstate; 2968 2969 wlock_acquire(rtld_bind_lock, &lockstate); 2970 root = dlcheck(handle); 2971 if (root == NULL) { 2972 lock_release(rtld_bind_lock, &lockstate); 2973 return -1; 2974 } 2975 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2976 root->path); 2977 2978 /* Unreference the object and its dependencies. */ 2979 root->dl_refcount--; 2980 2981 if (root->refcount == 1) { 2982 /* 2983 * The object will be no longer referenced, so we must unload it. 2984 * First, call the fini functions. 2985 */ 2986 objlist_call_fini(&list_fini, root, &lockstate); 2987 2988 unref_dag(root); 2989 2990 /* Finish cleaning up the newly-unreferenced objects. */ 2991 GDB_STATE(RT_DELETE,&root->linkmap); 2992 unload_object(root); 2993 GDB_STATE(RT_CONSISTENT,NULL); 2994 } else 2995 unref_dag(root); 2996 2997 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2998 lock_release(rtld_bind_lock, &lockstate); 2999 return 0; 3000 } 3001 3002 char * 3003 dlerror(void) 3004 { 3005 char *msg = error_message; 3006 error_message = NULL; 3007 return msg; 3008 } 3009 3010 /* 3011 * This function is deprecated and has no effect. 3012 */ 3013 void 3014 dllockinit(void *context, 3015 void *(*lock_create)(void *context), 3016 void (*rlock_acquire)(void *lock), 3017 void (*wlock_acquire)(void *lock), 3018 void (*lock_release)(void *lock), 3019 void (*lock_destroy)(void *lock), 3020 void (*context_destroy)(void *context)) 3021 { 3022 static void *cur_context; 3023 static void (*cur_context_destroy)(void *); 3024 3025 /* Just destroy the context from the previous call, if necessary. */ 3026 if (cur_context_destroy != NULL) 3027 cur_context_destroy(cur_context); 3028 cur_context = context; 3029 cur_context_destroy = context_destroy; 3030 } 3031 3032 void * 3033 dlopen(const char *name, int mode) 3034 { 3035 3036 return (rtld_dlopen(name, -1, mode)); 3037 } 3038 3039 void * 3040 fdlopen(int fd, int mode) 3041 { 3042 3043 return (rtld_dlopen(NULL, fd, mode)); 3044 } 3045 3046 static void * 3047 rtld_dlopen(const char *name, int fd, int mode) 3048 { 3049 RtldLockState lockstate; 3050 int lo_flags; 3051 3052 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3053 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3054 if (ld_tracing != NULL) { 3055 rlock_acquire(rtld_bind_lock, &lockstate); 3056 if (sigsetjmp(lockstate.env, 0) != 0) 3057 lock_upgrade(rtld_bind_lock, &lockstate); 3058 environ = (char **)*get_program_var_addr("environ", &lockstate); 3059 lock_release(rtld_bind_lock, &lockstate); 3060 } 3061 lo_flags = RTLD_LO_DLOPEN; 3062 if (mode & RTLD_NODELETE) 3063 lo_flags |= RTLD_LO_NODELETE; 3064 if (mode & RTLD_NOLOAD) 3065 lo_flags |= RTLD_LO_NOLOAD; 3066 if (ld_tracing != NULL) 3067 lo_flags |= RTLD_LO_TRACE; 3068 3069 return (dlopen_object(name, fd, obj_main, lo_flags, 3070 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3071 } 3072 3073 static void 3074 dlopen_cleanup(Obj_Entry *obj) 3075 { 3076 3077 obj->dl_refcount--; 3078 unref_dag(obj); 3079 if (obj->refcount == 0) 3080 unload_object(obj); 3081 } 3082 3083 static Obj_Entry * 3084 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3085 int mode, RtldLockState *lockstate) 3086 { 3087 Obj_Entry *old_obj_tail; 3088 Obj_Entry *obj; 3089 Objlist initlist; 3090 RtldLockState mlockstate; 3091 int result; 3092 3093 objlist_init(&initlist); 3094 3095 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3096 wlock_acquire(rtld_bind_lock, &mlockstate); 3097 lockstate = &mlockstate; 3098 } 3099 GDB_STATE(RT_ADD,NULL); 3100 3101 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3102 obj = NULL; 3103 if (name == NULL && fd == -1) { 3104 obj = obj_main; 3105 obj->refcount++; 3106 } else { 3107 obj = load_object(name, fd, refobj, lo_flags); 3108 } 3109 3110 if (obj) { 3111 obj->dl_refcount++; 3112 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3113 objlist_push_tail(&list_global, obj); 3114 if (globallist_next(old_obj_tail) != NULL) { 3115 /* We loaded something new. */ 3116 assert(globallist_next(old_obj_tail) == obj); 3117 result = load_needed_objects(obj, 3118 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3119 init_dag(obj); 3120 ref_dag(obj); 3121 if (result != -1) 3122 result = rtld_verify_versions(&obj->dagmembers); 3123 if (result != -1 && ld_tracing) 3124 goto trace; 3125 if (result == -1 || relocate_object_dag(obj, 3126 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3127 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3128 lockstate) == -1) { 3129 dlopen_cleanup(obj); 3130 obj = NULL; 3131 } else if (lo_flags & RTLD_LO_EARLY) { 3132 /* 3133 * Do not call the init functions for early loaded 3134 * filtees. The image is still not initialized enough 3135 * for them to work. 3136 * 3137 * Our object is found by the global object list and 3138 * will be ordered among all init calls done right 3139 * before transferring control to main. 3140 */ 3141 } else { 3142 /* Make list of init functions to call. */ 3143 initlist_add_objects(obj, obj, &initlist); 3144 } 3145 /* 3146 * Process all no_delete or global objects here, given 3147 * them own DAGs to prevent their dependencies from being 3148 * unloaded. This has to be done after we have loaded all 3149 * of the dependencies, so that we do not miss any. 3150 */ 3151 if (obj != NULL) 3152 process_z(obj); 3153 } else { 3154 /* 3155 * Bump the reference counts for objects on this DAG. If 3156 * this is the first dlopen() call for the object that was 3157 * already loaded as a dependency, initialize the dag 3158 * starting at it. 3159 */ 3160 init_dag(obj); 3161 ref_dag(obj); 3162 3163 if ((lo_flags & RTLD_LO_TRACE) != 0) 3164 goto trace; 3165 } 3166 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3167 obj->z_nodelete) && !obj->ref_nodel) { 3168 dbg("obj %s nodelete", obj->path); 3169 ref_dag(obj); 3170 obj->z_nodelete = obj->ref_nodel = true; 3171 } 3172 } 3173 3174 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3175 name); 3176 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3177 3178 if (!(lo_flags & RTLD_LO_EARLY)) { 3179 map_stacks_exec(lockstate); 3180 } 3181 3182 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3183 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3184 lockstate) == -1) { 3185 objlist_clear(&initlist); 3186 dlopen_cleanup(obj); 3187 if (lockstate == &mlockstate) 3188 lock_release(rtld_bind_lock, lockstate); 3189 return (NULL); 3190 } 3191 3192 if (!(lo_flags & RTLD_LO_EARLY)) { 3193 /* Call the init functions. */ 3194 objlist_call_init(&initlist, lockstate); 3195 } 3196 objlist_clear(&initlist); 3197 if (lockstate == &mlockstate) 3198 lock_release(rtld_bind_lock, lockstate); 3199 return obj; 3200 trace: 3201 trace_loaded_objects(obj); 3202 if (lockstate == &mlockstate) 3203 lock_release(rtld_bind_lock, lockstate); 3204 exit(0); 3205 } 3206 3207 static void * 3208 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3209 int flags) 3210 { 3211 DoneList donelist; 3212 const Obj_Entry *obj, *defobj; 3213 const Elf_Sym *def; 3214 SymLook req; 3215 RtldLockState lockstate; 3216 tls_index ti; 3217 void *sym; 3218 int res; 3219 3220 def = NULL; 3221 defobj = NULL; 3222 symlook_init(&req, name); 3223 req.ventry = ve; 3224 req.flags = flags | SYMLOOK_IN_PLT; 3225 req.lockstate = &lockstate; 3226 3227 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3228 rlock_acquire(rtld_bind_lock, &lockstate); 3229 if (sigsetjmp(lockstate.env, 0) != 0) 3230 lock_upgrade(rtld_bind_lock, &lockstate); 3231 if (handle == NULL || handle == RTLD_NEXT || 3232 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3233 3234 if ((obj = obj_from_addr(retaddr)) == NULL) { 3235 _rtld_error("Cannot determine caller's shared object"); 3236 lock_release(rtld_bind_lock, &lockstate); 3237 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3238 return NULL; 3239 } 3240 if (handle == NULL) { /* Just the caller's shared object. */ 3241 res = symlook_obj(&req, obj); 3242 if (res == 0) { 3243 def = req.sym_out; 3244 defobj = req.defobj_out; 3245 } 3246 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3247 handle == RTLD_SELF) { /* ... caller included */ 3248 if (handle == RTLD_NEXT) 3249 obj = globallist_next(obj); 3250 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 3251 if (obj->marker) 3252 continue; 3253 res = symlook_obj(&req, obj); 3254 if (res == 0) { 3255 if (def == NULL || 3256 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3257 def = req.sym_out; 3258 defobj = req.defobj_out; 3259 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3260 break; 3261 } 3262 } 3263 } 3264 /* 3265 * Search the dynamic linker itself, and possibly resolve the 3266 * symbol from there. This is how the application links to 3267 * dynamic linker services such as dlopen. 3268 */ 3269 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3270 res = symlook_obj(&req, &obj_rtld); 3271 if (res == 0) { 3272 def = req.sym_out; 3273 defobj = req.defobj_out; 3274 } 3275 } 3276 } else { 3277 assert(handle == RTLD_DEFAULT); 3278 res = symlook_default(&req, obj); 3279 if (res == 0) { 3280 defobj = req.defobj_out; 3281 def = req.sym_out; 3282 } 3283 } 3284 } else { 3285 if ((obj = dlcheck(handle)) == NULL) { 3286 lock_release(rtld_bind_lock, &lockstate); 3287 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3288 return NULL; 3289 } 3290 3291 donelist_init(&donelist); 3292 if (obj->mainprog) { 3293 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3294 res = symlook_global(&req, &donelist); 3295 if (res == 0) { 3296 def = req.sym_out; 3297 defobj = req.defobj_out; 3298 } 3299 /* 3300 * Search the dynamic linker itself, and possibly resolve the 3301 * symbol from there. This is how the application links to 3302 * dynamic linker services such as dlopen. 3303 */ 3304 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3305 res = symlook_obj(&req, &obj_rtld); 3306 if (res == 0) { 3307 def = req.sym_out; 3308 defobj = req.defobj_out; 3309 } 3310 } 3311 } 3312 else { 3313 /* Search the whole DAG rooted at the given object. */ 3314 res = symlook_list(&req, &obj->dagmembers, &donelist); 3315 if (res == 0) { 3316 def = req.sym_out; 3317 defobj = req.defobj_out; 3318 } 3319 } 3320 } 3321 3322 if (def != NULL) { 3323 lock_release(rtld_bind_lock, &lockstate); 3324 3325 /* 3326 * The value required by the caller is derived from the value 3327 * of the symbol. this is simply the relocated value of the 3328 * symbol. 3329 */ 3330 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3331 sym = make_function_pointer(def, defobj); 3332 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3333 sym = rtld_resolve_ifunc(defobj, def); 3334 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3335 ti.ti_module = defobj->tlsindex; 3336 ti.ti_offset = def->st_value; 3337 sym = __tls_get_addr(&ti); 3338 } else 3339 sym = defobj->relocbase + def->st_value; 3340 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3341 return (sym); 3342 } 3343 3344 _rtld_error("Undefined symbol \"%s\"", name); 3345 lock_release(rtld_bind_lock, &lockstate); 3346 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3347 return NULL; 3348 } 3349 3350 void * 3351 dlsym(void *handle, const char *name) 3352 { 3353 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3354 SYMLOOK_DLSYM); 3355 } 3356 3357 dlfunc_t 3358 dlfunc(void *handle, const char *name) 3359 { 3360 union { 3361 void *d; 3362 dlfunc_t f; 3363 } rv; 3364 3365 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3366 SYMLOOK_DLSYM); 3367 return (rv.f); 3368 } 3369 3370 void * 3371 dlvsym(void *handle, const char *name, const char *version) 3372 { 3373 Ver_Entry ventry; 3374 3375 ventry.name = version; 3376 ventry.file = NULL; 3377 ventry.hash = elf_hash(version); 3378 ventry.flags= 0; 3379 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3380 SYMLOOK_DLSYM); 3381 } 3382 3383 int 3384 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3385 { 3386 const Obj_Entry *obj; 3387 RtldLockState lockstate; 3388 3389 rlock_acquire(rtld_bind_lock, &lockstate); 3390 obj = obj_from_addr(addr); 3391 if (obj == NULL) { 3392 _rtld_error("No shared object contains address"); 3393 lock_release(rtld_bind_lock, &lockstate); 3394 return (0); 3395 } 3396 rtld_fill_dl_phdr_info(obj, phdr_info); 3397 lock_release(rtld_bind_lock, &lockstate); 3398 return (1); 3399 } 3400 3401 int 3402 dladdr(const void *addr, Dl_info *info) 3403 { 3404 const Obj_Entry *obj; 3405 const Elf_Sym *def; 3406 void *symbol_addr; 3407 unsigned long symoffset; 3408 RtldLockState lockstate; 3409 3410 rlock_acquire(rtld_bind_lock, &lockstate); 3411 obj = obj_from_addr(addr); 3412 if (obj == NULL) { 3413 _rtld_error("No shared object contains address"); 3414 lock_release(rtld_bind_lock, &lockstate); 3415 return 0; 3416 } 3417 info->dli_fname = obj->path; 3418 info->dli_fbase = obj->mapbase; 3419 info->dli_saddr = (void *)0; 3420 info->dli_sname = NULL; 3421 3422 /* 3423 * Walk the symbol list looking for the symbol whose address is 3424 * closest to the address sent in. 3425 */ 3426 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3427 def = obj->symtab + symoffset; 3428 3429 /* 3430 * For skip the symbol if st_shndx is either SHN_UNDEF or 3431 * SHN_COMMON. 3432 */ 3433 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3434 continue; 3435 3436 /* 3437 * If the symbol is greater than the specified address, or if it 3438 * is further away from addr than the current nearest symbol, 3439 * then reject it. 3440 */ 3441 symbol_addr = obj->relocbase + def->st_value; 3442 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3443 continue; 3444 3445 /* Update our idea of the nearest symbol. */ 3446 info->dli_sname = obj->strtab + def->st_name; 3447 info->dli_saddr = symbol_addr; 3448 3449 /* Exact match? */ 3450 if (info->dli_saddr == addr) 3451 break; 3452 } 3453 lock_release(rtld_bind_lock, &lockstate); 3454 return 1; 3455 } 3456 3457 int 3458 dlinfo(void *handle, int request, void *p) 3459 { 3460 const Obj_Entry *obj; 3461 RtldLockState lockstate; 3462 int error; 3463 3464 rlock_acquire(rtld_bind_lock, &lockstate); 3465 3466 if (handle == NULL || handle == RTLD_SELF) { 3467 void *retaddr; 3468 3469 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3470 if ((obj = obj_from_addr(retaddr)) == NULL) 3471 _rtld_error("Cannot determine caller's shared object"); 3472 } else 3473 obj = dlcheck(handle); 3474 3475 if (obj == NULL) { 3476 lock_release(rtld_bind_lock, &lockstate); 3477 return (-1); 3478 } 3479 3480 error = 0; 3481 switch (request) { 3482 case RTLD_DI_LINKMAP: 3483 *((struct link_map const **)p) = &obj->linkmap; 3484 break; 3485 case RTLD_DI_ORIGIN: 3486 error = rtld_dirname(obj->path, p); 3487 break; 3488 3489 case RTLD_DI_SERINFOSIZE: 3490 case RTLD_DI_SERINFO: 3491 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3492 break; 3493 3494 default: 3495 _rtld_error("Invalid request %d passed to dlinfo()", request); 3496 error = -1; 3497 } 3498 3499 lock_release(rtld_bind_lock, &lockstate); 3500 3501 return (error); 3502 } 3503 3504 static void 3505 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3506 { 3507 3508 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3509 phdr_info->dlpi_name = obj->path; 3510 phdr_info->dlpi_phdr = obj->phdr; 3511 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3512 phdr_info->dlpi_tls_modid = obj->tlsindex; 3513 phdr_info->dlpi_tls_data = obj->tlsinit; 3514 phdr_info->dlpi_adds = obj_loads; 3515 phdr_info->dlpi_subs = obj_loads - obj_count; 3516 } 3517 3518 int 3519 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3520 { 3521 struct dl_phdr_info phdr_info; 3522 Obj_Entry *obj, marker; 3523 RtldLockState bind_lockstate, phdr_lockstate; 3524 int error; 3525 3526 bzero(&marker, sizeof(marker)); 3527 marker.marker = true; 3528 error = 0; 3529 3530 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3531 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3532 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3533 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3534 rtld_fill_dl_phdr_info(obj, &phdr_info); 3535 lock_release(rtld_bind_lock, &bind_lockstate); 3536 lock_release(rtld_phdr_lock, &phdr_lockstate); 3537 3538 error = callback(&phdr_info, sizeof phdr_info, param); 3539 3540 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3541 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3542 obj = globallist_next(&marker); 3543 TAILQ_REMOVE(&obj_list, &marker, next); 3544 if (error != 0) { 3545 lock_release(rtld_bind_lock, &bind_lockstate); 3546 lock_release(rtld_phdr_lock, &phdr_lockstate); 3547 return (error); 3548 } 3549 } 3550 3551 if (error == 0) { 3552 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3553 lock_release(rtld_bind_lock, &bind_lockstate); 3554 lock_release(rtld_phdr_lock, &phdr_lockstate); 3555 error = callback(&phdr_info, sizeof(phdr_info), param); 3556 } 3557 return (error); 3558 } 3559 3560 static void * 3561 fill_search_info(const char *dir, size_t dirlen, void *param) 3562 { 3563 struct fill_search_info_args *arg; 3564 3565 arg = param; 3566 3567 if (arg->request == RTLD_DI_SERINFOSIZE) { 3568 arg->serinfo->dls_cnt ++; 3569 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3570 } else { 3571 struct dl_serpath *s_entry; 3572 3573 s_entry = arg->serpath; 3574 s_entry->dls_name = arg->strspace; 3575 s_entry->dls_flags = arg->flags; 3576 3577 strncpy(arg->strspace, dir, dirlen); 3578 arg->strspace[dirlen] = '\0'; 3579 3580 arg->strspace += dirlen + 1; 3581 arg->serpath++; 3582 } 3583 3584 return (NULL); 3585 } 3586 3587 static int 3588 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3589 { 3590 struct dl_serinfo _info; 3591 struct fill_search_info_args args; 3592 3593 args.request = RTLD_DI_SERINFOSIZE; 3594 args.serinfo = &_info; 3595 3596 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3597 _info.dls_cnt = 0; 3598 3599 path_enumerate(obj->rpath, fill_search_info, &args); 3600 path_enumerate(ld_library_path, fill_search_info, &args); 3601 path_enumerate(obj->runpath, fill_search_info, &args); 3602 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3603 if (!obj->z_nodeflib) 3604 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3605 3606 3607 if (request == RTLD_DI_SERINFOSIZE) { 3608 info->dls_size = _info.dls_size; 3609 info->dls_cnt = _info.dls_cnt; 3610 return (0); 3611 } 3612 3613 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3614 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3615 return (-1); 3616 } 3617 3618 args.request = RTLD_DI_SERINFO; 3619 args.serinfo = info; 3620 args.serpath = &info->dls_serpath[0]; 3621 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3622 3623 args.flags = LA_SER_RUNPATH; 3624 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3625 return (-1); 3626 3627 args.flags = LA_SER_LIBPATH; 3628 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3629 return (-1); 3630 3631 args.flags = LA_SER_RUNPATH; 3632 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3633 return (-1); 3634 3635 args.flags = LA_SER_CONFIG; 3636 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3637 != NULL) 3638 return (-1); 3639 3640 args.flags = LA_SER_DEFAULT; 3641 if (!obj->z_nodeflib && 3642 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3643 return (-1); 3644 return (0); 3645 } 3646 3647 static int 3648 rtld_dirname(const char *path, char *bname) 3649 { 3650 const char *endp; 3651 3652 /* Empty or NULL string gets treated as "." */ 3653 if (path == NULL || *path == '\0') { 3654 bname[0] = '.'; 3655 bname[1] = '\0'; 3656 return (0); 3657 } 3658 3659 /* Strip trailing slashes */ 3660 endp = path + strlen(path) - 1; 3661 while (endp > path && *endp == '/') 3662 endp--; 3663 3664 /* Find the start of the dir */ 3665 while (endp > path && *endp != '/') 3666 endp--; 3667 3668 /* Either the dir is "/" or there are no slashes */ 3669 if (endp == path) { 3670 bname[0] = *endp == '/' ? '/' : '.'; 3671 bname[1] = '\0'; 3672 return (0); 3673 } else { 3674 do { 3675 endp--; 3676 } while (endp > path && *endp == '/'); 3677 } 3678 3679 if (endp - path + 2 > PATH_MAX) 3680 { 3681 _rtld_error("Filename is too long: %s", path); 3682 return(-1); 3683 } 3684 3685 strncpy(bname, path, endp - path + 1); 3686 bname[endp - path + 1] = '\0'; 3687 return (0); 3688 } 3689 3690 static int 3691 rtld_dirname_abs(const char *path, char *base) 3692 { 3693 char *last; 3694 3695 if (realpath(path, base) == NULL) 3696 return (-1); 3697 dbg("%s -> %s", path, base); 3698 last = strrchr(base, '/'); 3699 if (last == NULL) 3700 return (-1); 3701 if (last != base) 3702 *last = '\0'; 3703 return (0); 3704 } 3705 3706 static void 3707 linkmap_add(Obj_Entry *obj) 3708 { 3709 struct link_map *l = &obj->linkmap; 3710 struct link_map *prev; 3711 3712 obj->linkmap.l_name = obj->path; 3713 obj->linkmap.l_addr = obj->mapbase; 3714 obj->linkmap.l_ld = obj->dynamic; 3715 #ifdef __mips__ 3716 /* GDB needs load offset on MIPS to use the symbols */ 3717 obj->linkmap.l_offs = obj->relocbase; 3718 #endif 3719 3720 if (r_debug.r_map == NULL) { 3721 r_debug.r_map = l; 3722 return; 3723 } 3724 3725 /* 3726 * Scan to the end of the list, but not past the entry for the 3727 * dynamic linker, which we want to keep at the very end. 3728 */ 3729 for (prev = r_debug.r_map; 3730 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3731 prev = prev->l_next) 3732 ; 3733 3734 /* Link in the new entry. */ 3735 l->l_prev = prev; 3736 l->l_next = prev->l_next; 3737 if (l->l_next != NULL) 3738 l->l_next->l_prev = l; 3739 prev->l_next = l; 3740 } 3741 3742 static void 3743 linkmap_delete(Obj_Entry *obj) 3744 { 3745 struct link_map *l = &obj->linkmap; 3746 3747 if (l->l_prev == NULL) { 3748 if ((r_debug.r_map = l->l_next) != NULL) 3749 l->l_next->l_prev = NULL; 3750 return; 3751 } 3752 3753 if ((l->l_prev->l_next = l->l_next) != NULL) 3754 l->l_next->l_prev = l->l_prev; 3755 } 3756 3757 /* 3758 * Function for the debugger to set a breakpoint on to gain control. 3759 * 3760 * The two parameters allow the debugger to easily find and determine 3761 * what the runtime loader is doing and to whom it is doing it. 3762 * 3763 * When the loadhook trap is hit (r_debug_state, set at program 3764 * initialization), the arguments can be found on the stack: 3765 * 3766 * +8 struct link_map *m 3767 * +4 struct r_debug *rd 3768 * +0 RetAddr 3769 */ 3770 void 3771 r_debug_state(struct r_debug* rd, struct link_map *m) 3772 { 3773 /* 3774 * The following is a hack to force the compiler to emit calls to 3775 * this function, even when optimizing. If the function is empty, 3776 * the compiler is not obliged to emit any code for calls to it, 3777 * even when marked __noinline. However, gdb depends on those 3778 * calls being made. 3779 */ 3780 __compiler_membar(); 3781 } 3782 3783 /* 3784 * A function called after init routines have completed. This can be used to 3785 * break before a program's entry routine is called, and can be used when 3786 * main is not available in the symbol table. 3787 */ 3788 void 3789 _r_debug_postinit(struct link_map *m) 3790 { 3791 3792 /* See r_debug_state(). */ 3793 __compiler_membar(); 3794 } 3795 3796 /* 3797 * Get address of the pointer variable in the main program. 3798 * Prefer non-weak symbol over the weak one. 3799 */ 3800 static const void ** 3801 get_program_var_addr(const char *name, RtldLockState *lockstate) 3802 { 3803 SymLook req; 3804 DoneList donelist; 3805 3806 symlook_init(&req, name); 3807 req.lockstate = lockstate; 3808 donelist_init(&donelist); 3809 if (symlook_global(&req, &donelist) != 0) 3810 return (NULL); 3811 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3812 return ((const void **)make_function_pointer(req.sym_out, 3813 req.defobj_out)); 3814 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3815 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3816 else 3817 return ((const void **)(req.defobj_out->relocbase + 3818 req.sym_out->st_value)); 3819 } 3820 3821 /* 3822 * Set a pointer variable in the main program to the given value. This 3823 * is used to set key variables such as "environ" before any of the 3824 * init functions are called. 3825 */ 3826 static void 3827 set_program_var(const char *name, const void *value) 3828 { 3829 const void **addr; 3830 3831 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3832 dbg("\"%s\": *%p <-- %p", name, addr, value); 3833 *addr = value; 3834 } 3835 } 3836 3837 /* 3838 * Search the global objects, including dependencies and main object, 3839 * for the given symbol. 3840 */ 3841 static int 3842 symlook_global(SymLook *req, DoneList *donelist) 3843 { 3844 SymLook req1; 3845 const Objlist_Entry *elm; 3846 int res; 3847 3848 symlook_init_from_req(&req1, req); 3849 3850 /* Search all objects loaded at program start up. */ 3851 if (req->defobj_out == NULL || 3852 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3853 res = symlook_list(&req1, &list_main, donelist); 3854 if (res == 0 && (req->defobj_out == NULL || 3855 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3856 req->sym_out = req1.sym_out; 3857 req->defobj_out = req1.defobj_out; 3858 assert(req->defobj_out != NULL); 3859 } 3860 } 3861 3862 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3863 STAILQ_FOREACH(elm, &list_global, link) { 3864 if (req->defobj_out != NULL && 3865 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3866 break; 3867 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3868 if (res == 0 && (req->defobj_out == NULL || 3869 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3870 req->sym_out = req1.sym_out; 3871 req->defobj_out = req1.defobj_out; 3872 assert(req->defobj_out != NULL); 3873 } 3874 } 3875 3876 return (req->sym_out != NULL ? 0 : ESRCH); 3877 } 3878 3879 /* 3880 * Given a symbol name in a referencing object, find the corresponding 3881 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3882 * no definition was found. Returns a pointer to the Obj_Entry of the 3883 * defining object via the reference parameter DEFOBJ_OUT. 3884 */ 3885 static int 3886 symlook_default(SymLook *req, const Obj_Entry *refobj) 3887 { 3888 DoneList donelist; 3889 const Objlist_Entry *elm; 3890 SymLook req1; 3891 int res; 3892 3893 donelist_init(&donelist); 3894 symlook_init_from_req(&req1, req); 3895 3896 /* Look first in the referencing object if linked symbolically. */ 3897 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3898 res = symlook_obj(&req1, refobj); 3899 if (res == 0) { 3900 req->sym_out = req1.sym_out; 3901 req->defobj_out = req1.defobj_out; 3902 assert(req->defobj_out != NULL); 3903 } 3904 } 3905 3906 symlook_global(req, &donelist); 3907 3908 /* Search all dlopened DAGs containing the referencing object. */ 3909 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3910 if (req->sym_out != NULL && 3911 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3912 break; 3913 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3914 if (res == 0 && (req->sym_out == NULL || 3915 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3916 req->sym_out = req1.sym_out; 3917 req->defobj_out = req1.defobj_out; 3918 assert(req->defobj_out != NULL); 3919 } 3920 } 3921 3922 /* 3923 * Search the dynamic linker itself, and possibly resolve the 3924 * symbol from there. This is how the application links to 3925 * dynamic linker services such as dlopen. 3926 */ 3927 if (req->sym_out == NULL || 3928 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3929 res = symlook_obj(&req1, &obj_rtld); 3930 if (res == 0) { 3931 req->sym_out = req1.sym_out; 3932 req->defobj_out = req1.defobj_out; 3933 assert(req->defobj_out != NULL); 3934 } 3935 } 3936 3937 return (req->sym_out != NULL ? 0 : ESRCH); 3938 } 3939 3940 static int 3941 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3942 { 3943 const Elf_Sym *def; 3944 const Obj_Entry *defobj; 3945 const Objlist_Entry *elm; 3946 SymLook req1; 3947 int res; 3948 3949 def = NULL; 3950 defobj = NULL; 3951 STAILQ_FOREACH(elm, objlist, link) { 3952 if (donelist_check(dlp, elm->obj)) 3953 continue; 3954 symlook_init_from_req(&req1, req); 3955 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3956 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3957 def = req1.sym_out; 3958 defobj = req1.defobj_out; 3959 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3960 break; 3961 } 3962 } 3963 } 3964 if (def != NULL) { 3965 req->sym_out = def; 3966 req->defobj_out = defobj; 3967 return (0); 3968 } 3969 return (ESRCH); 3970 } 3971 3972 /* 3973 * Search the chain of DAGS cointed to by the given Needed_Entry 3974 * for a symbol of the given name. Each DAG is scanned completely 3975 * before advancing to the next one. Returns a pointer to the symbol, 3976 * or NULL if no definition was found. 3977 */ 3978 static int 3979 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3980 { 3981 const Elf_Sym *def; 3982 const Needed_Entry *n; 3983 const Obj_Entry *defobj; 3984 SymLook req1; 3985 int res; 3986 3987 def = NULL; 3988 defobj = NULL; 3989 symlook_init_from_req(&req1, req); 3990 for (n = needed; n != NULL; n = n->next) { 3991 if (n->obj == NULL || 3992 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3993 continue; 3994 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3995 def = req1.sym_out; 3996 defobj = req1.defobj_out; 3997 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3998 break; 3999 } 4000 } 4001 if (def != NULL) { 4002 req->sym_out = def; 4003 req->defobj_out = defobj; 4004 return (0); 4005 } 4006 return (ESRCH); 4007 } 4008 4009 /* 4010 * Search the symbol table of a single shared object for a symbol of 4011 * the given name and version, if requested. Returns a pointer to the 4012 * symbol, or NULL if no definition was found. If the object is 4013 * filter, return filtered symbol from filtee. 4014 * 4015 * The symbol's hash value is passed in for efficiency reasons; that 4016 * eliminates many recomputations of the hash value. 4017 */ 4018 int 4019 symlook_obj(SymLook *req, const Obj_Entry *obj) 4020 { 4021 DoneList donelist; 4022 SymLook req1; 4023 int flags, res, mres; 4024 4025 /* 4026 * If there is at least one valid hash at this point, we prefer to 4027 * use the faster GNU version if available. 4028 */ 4029 if (obj->valid_hash_gnu) 4030 mres = symlook_obj1_gnu(req, obj); 4031 else if (obj->valid_hash_sysv) 4032 mres = symlook_obj1_sysv(req, obj); 4033 else 4034 return (EINVAL); 4035 4036 if (mres == 0) { 4037 if (obj->needed_filtees != NULL) { 4038 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4039 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4040 donelist_init(&donelist); 4041 symlook_init_from_req(&req1, req); 4042 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4043 if (res == 0) { 4044 req->sym_out = req1.sym_out; 4045 req->defobj_out = req1.defobj_out; 4046 } 4047 return (res); 4048 } 4049 if (obj->needed_aux_filtees != NULL) { 4050 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4051 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4052 donelist_init(&donelist); 4053 symlook_init_from_req(&req1, req); 4054 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4055 if (res == 0) { 4056 req->sym_out = req1.sym_out; 4057 req->defobj_out = req1.defobj_out; 4058 return (res); 4059 } 4060 } 4061 } 4062 return (mres); 4063 } 4064 4065 /* Symbol match routine common to both hash functions */ 4066 static bool 4067 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4068 const unsigned long symnum) 4069 { 4070 Elf_Versym verndx; 4071 const Elf_Sym *symp; 4072 const char *strp; 4073 4074 symp = obj->symtab + symnum; 4075 strp = obj->strtab + symp->st_name; 4076 4077 switch (ELF_ST_TYPE(symp->st_info)) { 4078 case STT_FUNC: 4079 case STT_NOTYPE: 4080 case STT_OBJECT: 4081 case STT_COMMON: 4082 case STT_GNU_IFUNC: 4083 if (symp->st_value == 0) 4084 return (false); 4085 /* fallthrough */ 4086 case STT_TLS: 4087 if (symp->st_shndx != SHN_UNDEF) 4088 break; 4089 #ifndef __mips__ 4090 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4091 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4092 break; 4093 /* fallthrough */ 4094 #endif 4095 default: 4096 return (false); 4097 } 4098 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4099 return (false); 4100 4101 if (req->ventry == NULL) { 4102 if (obj->versyms != NULL) { 4103 verndx = VER_NDX(obj->versyms[symnum]); 4104 if (verndx > obj->vernum) { 4105 _rtld_error( 4106 "%s: symbol %s references wrong version %d", 4107 obj->path, obj->strtab + symnum, verndx); 4108 return (false); 4109 } 4110 /* 4111 * If we are not called from dlsym (i.e. this 4112 * is a normal relocation from unversioned 4113 * binary), accept the symbol immediately if 4114 * it happens to have first version after this 4115 * shared object became versioned. Otherwise, 4116 * if symbol is versioned and not hidden, 4117 * remember it. If it is the only symbol with 4118 * this name exported by the shared object, it 4119 * will be returned as a match by the calling 4120 * function. If symbol is global (verndx < 2) 4121 * accept it unconditionally. 4122 */ 4123 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4124 verndx == VER_NDX_GIVEN) { 4125 result->sym_out = symp; 4126 return (true); 4127 } 4128 else if (verndx >= VER_NDX_GIVEN) { 4129 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4130 == 0) { 4131 if (result->vsymp == NULL) 4132 result->vsymp = symp; 4133 result->vcount++; 4134 } 4135 return (false); 4136 } 4137 } 4138 result->sym_out = symp; 4139 return (true); 4140 } 4141 if (obj->versyms == NULL) { 4142 if (object_match_name(obj, req->ventry->name)) { 4143 _rtld_error("%s: object %s should provide version %s " 4144 "for symbol %s", obj_rtld.path, obj->path, 4145 req->ventry->name, obj->strtab + symnum); 4146 return (false); 4147 } 4148 } else { 4149 verndx = VER_NDX(obj->versyms[symnum]); 4150 if (verndx > obj->vernum) { 4151 _rtld_error("%s: symbol %s references wrong version %d", 4152 obj->path, obj->strtab + symnum, verndx); 4153 return (false); 4154 } 4155 if (obj->vertab[verndx].hash != req->ventry->hash || 4156 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4157 /* 4158 * Version does not match. Look if this is a 4159 * global symbol and if it is not hidden. If 4160 * global symbol (verndx < 2) is available, 4161 * use it. Do not return symbol if we are 4162 * called by dlvsym, because dlvsym looks for 4163 * a specific version and default one is not 4164 * what dlvsym wants. 4165 */ 4166 if ((req->flags & SYMLOOK_DLSYM) || 4167 (verndx >= VER_NDX_GIVEN) || 4168 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4169 return (false); 4170 } 4171 } 4172 result->sym_out = symp; 4173 return (true); 4174 } 4175 4176 /* 4177 * Search for symbol using SysV hash function. 4178 * obj->buckets is known not to be NULL at this point; the test for this was 4179 * performed with the obj->valid_hash_sysv assignment. 4180 */ 4181 static int 4182 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4183 { 4184 unsigned long symnum; 4185 Sym_Match_Result matchres; 4186 4187 matchres.sym_out = NULL; 4188 matchres.vsymp = NULL; 4189 matchres.vcount = 0; 4190 4191 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4192 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4193 if (symnum >= obj->nchains) 4194 return (ESRCH); /* Bad object */ 4195 4196 if (matched_symbol(req, obj, &matchres, symnum)) { 4197 req->sym_out = matchres.sym_out; 4198 req->defobj_out = obj; 4199 return (0); 4200 } 4201 } 4202 if (matchres.vcount == 1) { 4203 req->sym_out = matchres.vsymp; 4204 req->defobj_out = obj; 4205 return (0); 4206 } 4207 return (ESRCH); 4208 } 4209 4210 /* Search for symbol using GNU hash function */ 4211 static int 4212 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4213 { 4214 Elf_Addr bloom_word; 4215 const Elf32_Word *hashval; 4216 Elf32_Word bucket; 4217 Sym_Match_Result matchres; 4218 unsigned int h1, h2; 4219 unsigned long symnum; 4220 4221 matchres.sym_out = NULL; 4222 matchres.vsymp = NULL; 4223 matchres.vcount = 0; 4224 4225 /* Pick right bitmask word from Bloom filter array */ 4226 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4227 obj->maskwords_bm_gnu]; 4228 4229 /* Calculate modulus word size of gnu hash and its derivative */ 4230 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4231 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4232 4233 /* Filter out the "definitely not in set" queries */ 4234 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4235 return (ESRCH); 4236 4237 /* Locate hash chain and corresponding value element*/ 4238 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4239 if (bucket == 0) 4240 return (ESRCH); 4241 hashval = &obj->chain_zero_gnu[bucket]; 4242 do { 4243 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4244 symnum = hashval - obj->chain_zero_gnu; 4245 if (matched_symbol(req, obj, &matchres, symnum)) { 4246 req->sym_out = matchres.sym_out; 4247 req->defobj_out = obj; 4248 return (0); 4249 } 4250 } 4251 } while ((*hashval++ & 1) == 0); 4252 if (matchres.vcount == 1) { 4253 req->sym_out = matchres.vsymp; 4254 req->defobj_out = obj; 4255 return (0); 4256 } 4257 return (ESRCH); 4258 } 4259 4260 static void 4261 trace_loaded_objects(Obj_Entry *obj) 4262 { 4263 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4264 int c; 4265 4266 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4267 main_local = ""; 4268 4269 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4270 fmt1 = "\t%o => %p (%x)\n"; 4271 4272 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4273 fmt2 = "\t%o (%x)\n"; 4274 4275 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4276 4277 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4278 Needed_Entry *needed; 4279 char *name, *path; 4280 bool is_lib; 4281 4282 if (obj->marker) 4283 continue; 4284 if (list_containers && obj->needed != NULL) 4285 rtld_printf("%s:\n", obj->path); 4286 for (needed = obj->needed; needed; needed = needed->next) { 4287 if (needed->obj != NULL) { 4288 if (needed->obj->traced && !list_containers) 4289 continue; 4290 needed->obj->traced = true; 4291 path = needed->obj->path; 4292 } else 4293 path = "not found"; 4294 4295 name = (char *)obj->strtab + needed->name; 4296 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4297 4298 fmt = is_lib ? fmt1 : fmt2; 4299 while ((c = *fmt++) != '\0') { 4300 switch (c) { 4301 default: 4302 rtld_putchar(c); 4303 continue; 4304 case '\\': 4305 switch (c = *fmt) { 4306 case '\0': 4307 continue; 4308 case 'n': 4309 rtld_putchar('\n'); 4310 break; 4311 case 't': 4312 rtld_putchar('\t'); 4313 break; 4314 } 4315 break; 4316 case '%': 4317 switch (c = *fmt) { 4318 case '\0': 4319 continue; 4320 case '%': 4321 default: 4322 rtld_putchar(c); 4323 break; 4324 case 'A': 4325 rtld_putstr(main_local); 4326 break; 4327 case 'a': 4328 rtld_putstr(obj_main->path); 4329 break; 4330 case 'o': 4331 rtld_putstr(name); 4332 break; 4333 #if 0 4334 case 'm': 4335 rtld_printf("%d", sodp->sod_major); 4336 break; 4337 case 'n': 4338 rtld_printf("%d", sodp->sod_minor); 4339 break; 4340 #endif 4341 case 'p': 4342 rtld_putstr(path); 4343 break; 4344 case 'x': 4345 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4346 0); 4347 break; 4348 } 4349 break; 4350 } 4351 ++fmt; 4352 } 4353 } 4354 } 4355 } 4356 4357 /* 4358 * Unload a dlopened object and its dependencies from memory and from 4359 * our data structures. It is assumed that the DAG rooted in the 4360 * object has already been unreferenced, and that the object has a 4361 * reference count of 0. 4362 */ 4363 static void 4364 unload_object(Obj_Entry *root) 4365 { 4366 Obj_Entry *obj, *obj1; 4367 4368 assert(root->refcount == 0); 4369 4370 /* 4371 * Pass over the DAG removing unreferenced objects from 4372 * appropriate lists. 4373 */ 4374 unlink_object(root); 4375 4376 /* Unmap all objects that are no longer referenced. */ 4377 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4378 if (obj->marker || obj->refcount != 0) 4379 continue; 4380 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4381 obj->mapsize, 0, obj->path); 4382 dbg("unloading \"%s\"", obj->path); 4383 unload_filtees(root); 4384 munmap(obj->mapbase, obj->mapsize); 4385 linkmap_delete(obj); 4386 TAILQ_REMOVE(&obj_list, obj, next); 4387 obj_count--; 4388 obj_free(obj); 4389 } 4390 } 4391 4392 static void 4393 unlink_object(Obj_Entry *root) 4394 { 4395 Objlist_Entry *elm; 4396 4397 if (root->refcount == 0) { 4398 /* Remove the object from the RTLD_GLOBAL list. */ 4399 objlist_remove(&list_global, root); 4400 4401 /* Remove the object from all objects' DAG lists. */ 4402 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4403 objlist_remove(&elm->obj->dldags, root); 4404 if (elm->obj != root) 4405 unlink_object(elm->obj); 4406 } 4407 } 4408 } 4409 4410 static void 4411 ref_dag(Obj_Entry *root) 4412 { 4413 Objlist_Entry *elm; 4414 4415 assert(root->dag_inited); 4416 STAILQ_FOREACH(elm, &root->dagmembers, link) 4417 elm->obj->refcount++; 4418 } 4419 4420 static void 4421 unref_dag(Obj_Entry *root) 4422 { 4423 Objlist_Entry *elm; 4424 4425 assert(root->dag_inited); 4426 STAILQ_FOREACH(elm, &root->dagmembers, link) 4427 elm->obj->refcount--; 4428 } 4429 4430 /* 4431 * Common code for MD __tls_get_addr(). 4432 */ 4433 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4434 static void * 4435 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4436 { 4437 Elf_Addr *newdtv, *dtv; 4438 RtldLockState lockstate; 4439 int to_copy; 4440 4441 dtv = *dtvp; 4442 /* Check dtv generation in case new modules have arrived */ 4443 if (dtv[0] != tls_dtv_generation) { 4444 wlock_acquire(rtld_bind_lock, &lockstate); 4445 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4446 to_copy = dtv[1]; 4447 if (to_copy > tls_max_index) 4448 to_copy = tls_max_index; 4449 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4450 newdtv[0] = tls_dtv_generation; 4451 newdtv[1] = tls_max_index; 4452 free(dtv); 4453 lock_release(rtld_bind_lock, &lockstate); 4454 dtv = *dtvp = newdtv; 4455 } 4456 4457 /* Dynamically allocate module TLS if necessary */ 4458 if (dtv[index + 1] == 0) { 4459 /* Signal safe, wlock will block out signals. */ 4460 wlock_acquire(rtld_bind_lock, &lockstate); 4461 if (!dtv[index + 1]) 4462 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4463 lock_release(rtld_bind_lock, &lockstate); 4464 } 4465 return ((void *)(dtv[index + 1] + offset)); 4466 } 4467 4468 void * 4469 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4470 { 4471 Elf_Addr *dtv; 4472 4473 dtv = *dtvp; 4474 /* Check dtv generation in case new modules have arrived */ 4475 if (__predict_true(dtv[0] == tls_dtv_generation && 4476 dtv[index + 1] != 0)) 4477 return ((void *)(dtv[index + 1] + offset)); 4478 return (tls_get_addr_slow(dtvp, index, offset)); 4479 } 4480 4481 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4482 defined(__powerpc__) || defined(__riscv__) 4483 4484 /* 4485 * Allocate Static TLS using the Variant I method. 4486 */ 4487 void * 4488 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4489 { 4490 Obj_Entry *obj; 4491 char *tcb; 4492 Elf_Addr **tls; 4493 Elf_Addr *dtv; 4494 Elf_Addr addr; 4495 int i; 4496 4497 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4498 return (oldtcb); 4499 4500 assert(tcbsize >= TLS_TCB_SIZE); 4501 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4502 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4503 4504 if (oldtcb != NULL) { 4505 memcpy(tls, oldtcb, tls_static_space); 4506 free(oldtcb); 4507 4508 /* Adjust the DTV. */ 4509 dtv = tls[0]; 4510 for (i = 0; i < dtv[1]; i++) { 4511 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4512 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4513 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4514 } 4515 } 4516 } else { 4517 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4518 tls[0] = dtv; 4519 dtv[0] = tls_dtv_generation; 4520 dtv[1] = tls_max_index; 4521 4522 for (obj = globallist_curr(objs); obj != NULL; 4523 obj = globallist_next(obj)) { 4524 if (obj->tlsoffset > 0) { 4525 addr = (Elf_Addr)tls + obj->tlsoffset; 4526 if (obj->tlsinitsize > 0) 4527 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4528 if (obj->tlssize > obj->tlsinitsize) 4529 memset((void*) (addr + obj->tlsinitsize), 0, 4530 obj->tlssize - obj->tlsinitsize); 4531 dtv[obj->tlsindex + 1] = addr; 4532 } 4533 } 4534 } 4535 4536 return (tcb); 4537 } 4538 4539 void 4540 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4541 { 4542 Elf_Addr *dtv; 4543 Elf_Addr tlsstart, tlsend; 4544 int dtvsize, i; 4545 4546 assert(tcbsize >= TLS_TCB_SIZE); 4547 4548 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4549 tlsend = tlsstart + tls_static_space; 4550 4551 dtv = *(Elf_Addr **)tlsstart; 4552 dtvsize = dtv[1]; 4553 for (i = 0; i < dtvsize; i++) { 4554 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4555 free((void*)dtv[i+2]); 4556 } 4557 } 4558 free(dtv); 4559 free(tcb); 4560 } 4561 4562 #endif 4563 4564 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4565 4566 /* 4567 * Allocate Static TLS using the Variant II method. 4568 */ 4569 void * 4570 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4571 { 4572 Obj_Entry *obj; 4573 size_t size, ralign; 4574 char *tls; 4575 Elf_Addr *dtv, *olddtv; 4576 Elf_Addr segbase, oldsegbase, addr; 4577 int i; 4578 4579 ralign = tcbalign; 4580 if (tls_static_max_align > ralign) 4581 ralign = tls_static_max_align; 4582 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4583 4584 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4585 tls = malloc_aligned(size, ralign); 4586 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4587 4588 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4589 ((Elf_Addr*)segbase)[0] = segbase; 4590 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4591 4592 dtv[0] = tls_dtv_generation; 4593 dtv[1] = tls_max_index; 4594 4595 if (oldtls) { 4596 /* 4597 * Copy the static TLS block over whole. 4598 */ 4599 oldsegbase = (Elf_Addr) oldtls; 4600 memcpy((void *)(segbase - tls_static_space), 4601 (const void *)(oldsegbase - tls_static_space), 4602 tls_static_space); 4603 4604 /* 4605 * If any dynamic TLS blocks have been created tls_get_addr(), 4606 * move them over. 4607 */ 4608 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4609 for (i = 0; i < olddtv[1]; i++) { 4610 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4611 dtv[i+2] = olddtv[i+2]; 4612 olddtv[i+2] = 0; 4613 } 4614 } 4615 4616 /* 4617 * We assume that this block was the one we created with 4618 * allocate_initial_tls(). 4619 */ 4620 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4621 } else { 4622 obj = objs; 4623 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4624 if (obj->marker || obj->tlsoffset == 0) 4625 continue; 4626 addr = segbase - obj->tlsoffset; 4627 memset((void*) (addr + obj->tlsinitsize), 4628 0, obj->tlssize - obj->tlsinitsize); 4629 if (obj->tlsinit) 4630 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4631 dtv[obj->tlsindex + 1] = addr; 4632 } 4633 } 4634 4635 return (void*) segbase; 4636 } 4637 4638 void 4639 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4640 { 4641 Elf_Addr* dtv; 4642 size_t size, ralign; 4643 int dtvsize, i; 4644 Elf_Addr tlsstart, tlsend; 4645 4646 /* 4647 * Figure out the size of the initial TLS block so that we can 4648 * find stuff which ___tls_get_addr() allocated dynamically. 4649 */ 4650 ralign = tcbalign; 4651 if (tls_static_max_align > ralign) 4652 ralign = tls_static_max_align; 4653 size = round(tls_static_space, ralign); 4654 4655 dtv = ((Elf_Addr**)tls)[1]; 4656 dtvsize = dtv[1]; 4657 tlsend = (Elf_Addr) tls; 4658 tlsstart = tlsend - size; 4659 for (i = 0; i < dtvsize; i++) { 4660 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4661 free_aligned((void *)dtv[i + 2]); 4662 } 4663 } 4664 4665 free_aligned((void *)tlsstart); 4666 free((void*) dtv); 4667 } 4668 4669 #endif 4670 4671 /* 4672 * Allocate TLS block for module with given index. 4673 */ 4674 void * 4675 allocate_module_tls(int index) 4676 { 4677 Obj_Entry* obj; 4678 char* p; 4679 4680 TAILQ_FOREACH(obj, &obj_list, next) { 4681 if (obj->marker) 4682 continue; 4683 if (obj->tlsindex == index) 4684 break; 4685 } 4686 if (!obj) { 4687 _rtld_error("Can't find module with TLS index %d", index); 4688 rtld_die(); 4689 } 4690 4691 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4692 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4693 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4694 4695 return p; 4696 } 4697 4698 bool 4699 allocate_tls_offset(Obj_Entry *obj) 4700 { 4701 size_t off; 4702 4703 if (obj->tls_done) 4704 return true; 4705 4706 if (obj->tlssize == 0) { 4707 obj->tls_done = true; 4708 return true; 4709 } 4710 4711 if (tls_last_offset == 0) 4712 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4713 else 4714 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4715 obj->tlssize, obj->tlsalign); 4716 4717 /* 4718 * If we have already fixed the size of the static TLS block, we 4719 * must stay within that size. When allocating the static TLS, we 4720 * leave a small amount of space spare to be used for dynamically 4721 * loading modules which use static TLS. 4722 */ 4723 if (tls_static_space != 0) { 4724 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4725 return false; 4726 } else if (obj->tlsalign > tls_static_max_align) { 4727 tls_static_max_align = obj->tlsalign; 4728 } 4729 4730 tls_last_offset = obj->tlsoffset = off; 4731 tls_last_size = obj->tlssize; 4732 obj->tls_done = true; 4733 4734 return true; 4735 } 4736 4737 void 4738 free_tls_offset(Obj_Entry *obj) 4739 { 4740 4741 /* 4742 * If we were the last thing to allocate out of the static TLS 4743 * block, we give our space back to the 'allocator'. This is a 4744 * simplistic workaround to allow libGL.so.1 to be loaded and 4745 * unloaded multiple times. 4746 */ 4747 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4748 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4749 tls_last_offset -= obj->tlssize; 4750 tls_last_size = 0; 4751 } 4752 } 4753 4754 void * 4755 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4756 { 4757 void *ret; 4758 RtldLockState lockstate; 4759 4760 wlock_acquire(rtld_bind_lock, &lockstate); 4761 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4762 tcbsize, tcbalign); 4763 lock_release(rtld_bind_lock, &lockstate); 4764 return (ret); 4765 } 4766 4767 void 4768 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4769 { 4770 RtldLockState lockstate; 4771 4772 wlock_acquire(rtld_bind_lock, &lockstate); 4773 free_tls(tcb, tcbsize, tcbalign); 4774 lock_release(rtld_bind_lock, &lockstate); 4775 } 4776 4777 static void 4778 object_add_name(Obj_Entry *obj, const char *name) 4779 { 4780 Name_Entry *entry; 4781 size_t len; 4782 4783 len = strlen(name); 4784 entry = malloc(sizeof(Name_Entry) + len); 4785 4786 if (entry != NULL) { 4787 strcpy(entry->name, name); 4788 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4789 } 4790 } 4791 4792 static int 4793 object_match_name(const Obj_Entry *obj, const char *name) 4794 { 4795 Name_Entry *entry; 4796 4797 STAILQ_FOREACH(entry, &obj->names, link) { 4798 if (strcmp(name, entry->name) == 0) 4799 return (1); 4800 } 4801 return (0); 4802 } 4803 4804 static Obj_Entry * 4805 locate_dependency(const Obj_Entry *obj, const char *name) 4806 { 4807 const Objlist_Entry *entry; 4808 const Needed_Entry *needed; 4809 4810 STAILQ_FOREACH(entry, &list_main, link) { 4811 if (object_match_name(entry->obj, name)) 4812 return entry->obj; 4813 } 4814 4815 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4816 if (strcmp(obj->strtab + needed->name, name) == 0 || 4817 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4818 /* 4819 * If there is DT_NEEDED for the name we are looking for, 4820 * we are all set. Note that object might not be found if 4821 * dependency was not loaded yet, so the function can 4822 * return NULL here. This is expected and handled 4823 * properly by the caller. 4824 */ 4825 return (needed->obj); 4826 } 4827 } 4828 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4829 obj->path, name); 4830 rtld_die(); 4831 } 4832 4833 static int 4834 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4835 const Elf_Vernaux *vna) 4836 { 4837 const Elf_Verdef *vd; 4838 const char *vername; 4839 4840 vername = refobj->strtab + vna->vna_name; 4841 vd = depobj->verdef; 4842 if (vd == NULL) { 4843 _rtld_error("%s: version %s required by %s not defined", 4844 depobj->path, vername, refobj->path); 4845 return (-1); 4846 } 4847 for (;;) { 4848 if (vd->vd_version != VER_DEF_CURRENT) { 4849 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4850 depobj->path, vd->vd_version); 4851 return (-1); 4852 } 4853 if (vna->vna_hash == vd->vd_hash) { 4854 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4855 ((char *)vd + vd->vd_aux); 4856 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4857 return (0); 4858 } 4859 if (vd->vd_next == 0) 4860 break; 4861 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4862 } 4863 if (vna->vna_flags & VER_FLG_WEAK) 4864 return (0); 4865 _rtld_error("%s: version %s required by %s not found", 4866 depobj->path, vername, refobj->path); 4867 return (-1); 4868 } 4869 4870 static int 4871 rtld_verify_object_versions(Obj_Entry *obj) 4872 { 4873 const Elf_Verneed *vn; 4874 const Elf_Verdef *vd; 4875 const Elf_Verdaux *vda; 4876 const Elf_Vernaux *vna; 4877 const Obj_Entry *depobj; 4878 int maxvernum, vernum; 4879 4880 if (obj->ver_checked) 4881 return (0); 4882 obj->ver_checked = true; 4883 4884 maxvernum = 0; 4885 /* 4886 * Walk over defined and required version records and figure out 4887 * max index used by any of them. Do very basic sanity checking 4888 * while there. 4889 */ 4890 vn = obj->verneed; 4891 while (vn != NULL) { 4892 if (vn->vn_version != VER_NEED_CURRENT) { 4893 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4894 obj->path, vn->vn_version); 4895 return (-1); 4896 } 4897 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4898 for (;;) { 4899 vernum = VER_NEED_IDX(vna->vna_other); 4900 if (vernum > maxvernum) 4901 maxvernum = vernum; 4902 if (vna->vna_next == 0) 4903 break; 4904 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4905 } 4906 if (vn->vn_next == 0) 4907 break; 4908 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4909 } 4910 4911 vd = obj->verdef; 4912 while (vd != NULL) { 4913 if (vd->vd_version != VER_DEF_CURRENT) { 4914 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4915 obj->path, vd->vd_version); 4916 return (-1); 4917 } 4918 vernum = VER_DEF_IDX(vd->vd_ndx); 4919 if (vernum > maxvernum) 4920 maxvernum = vernum; 4921 if (vd->vd_next == 0) 4922 break; 4923 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4924 } 4925 4926 if (maxvernum == 0) 4927 return (0); 4928 4929 /* 4930 * Store version information in array indexable by version index. 4931 * Verify that object version requirements are satisfied along the 4932 * way. 4933 */ 4934 obj->vernum = maxvernum + 1; 4935 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4936 4937 vd = obj->verdef; 4938 while (vd != NULL) { 4939 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4940 vernum = VER_DEF_IDX(vd->vd_ndx); 4941 assert(vernum <= maxvernum); 4942 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4943 obj->vertab[vernum].hash = vd->vd_hash; 4944 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4945 obj->vertab[vernum].file = NULL; 4946 obj->vertab[vernum].flags = 0; 4947 } 4948 if (vd->vd_next == 0) 4949 break; 4950 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4951 } 4952 4953 vn = obj->verneed; 4954 while (vn != NULL) { 4955 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4956 if (depobj == NULL) 4957 return (-1); 4958 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4959 for (;;) { 4960 if (check_object_provided_version(obj, depobj, vna)) 4961 return (-1); 4962 vernum = VER_NEED_IDX(vna->vna_other); 4963 assert(vernum <= maxvernum); 4964 obj->vertab[vernum].hash = vna->vna_hash; 4965 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4966 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4967 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4968 VER_INFO_HIDDEN : 0; 4969 if (vna->vna_next == 0) 4970 break; 4971 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4972 } 4973 if (vn->vn_next == 0) 4974 break; 4975 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4976 } 4977 return 0; 4978 } 4979 4980 static int 4981 rtld_verify_versions(const Objlist *objlist) 4982 { 4983 Objlist_Entry *entry; 4984 int rc; 4985 4986 rc = 0; 4987 STAILQ_FOREACH(entry, objlist, link) { 4988 /* 4989 * Skip dummy objects or objects that have their version requirements 4990 * already checked. 4991 */ 4992 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4993 continue; 4994 if (rtld_verify_object_versions(entry->obj) == -1) { 4995 rc = -1; 4996 if (ld_tracing == NULL) 4997 break; 4998 } 4999 } 5000 if (rc == 0 || ld_tracing != NULL) 5001 rc = rtld_verify_object_versions(&obj_rtld); 5002 return rc; 5003 } 5004 5005 const Ver_Entry * 5006 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5007 { 5008 Elf_Versym vernum; 5009 5010 if (obj->vertab) { 5011 vernum = VER_NDX(obj->versyms[symnum]); 5012 if (vernum >= obj->vernum) { 5013 _rtld_error("%s: symbol %s has wrong verneed value %d", 5014 obj->path, obj->strtab + symnum, vernum); 5015 } else if (obj->vertab[vernum].hash != 0) { 5016 return &obj->vertab[vernum]; 5017 } 5018 } 5019 return NULL; 5020 } 5021 5022 int 5023 _rtld_get_stack_prot(void) 5024 { 5025 5026 return (stack_prot); 5027 } 5028 5029 int 5030 _rtld_is_dlopened(void *arg) 5031 { 5032 Obj_Entry *obj; 5033 RtldLockState lockstate; 5034 int res; 5035 5036 rlock_acquire(rtld_bind_lock, &lockstate); 5037 obj = dlcheck(arg); 5038 if (obj == NULL) 5039 obj = obj_from_addr(arg); 5040 if (obj == NULL) { 5041 _rtld_error("No shared object contains address"); 5042 lock_release(rtld_bind_lock, &lockstate); 5043 return (-1); 5044 } 5045 res = obj->dlopened ? 1 : 0; 5046 lock_release(rtld_bind_lock, &lockstate); 5047 return (res); 5048 } 5049 5050 static void 5051 map_stacks_exec(RtldLockState *lockstate) 5052 { 5053 void (*thr_map_stacks_exec)(void); 5054 5055 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5056 return; 5057 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5058 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5059 if (thr_map_stacks_exec != NULL) { 5060 stack_prot |= PROT_EXEC; 5061 thr_map_stacks_exec(); 5062 } 5063 } 5064 5065 void 5066 symlook_init(SymLook *dst, const char *name) 5067 { 5068 5069 bzero(dst, sizeof(*dst)); 5070 dst->name = name; 5071 dst->hash = elf_hash(name); 5072 dst->hash_gnu = gnu_hash(name); 5073 } 5074 5075 static void 5076 symlook_init_from_req(SymLook *dst, const SymLook *src) 5077 { 5078 5079 dst->name = src->name; 5080 dst->hash = src->hash; 5081 dst->hash_gnu = src->hash_gnu; 5082 dst->ventry = src->ventry; 5083 dst->flags = src->flags; 5084 dst->defobj_out = NULL; 5085 dst->sym_out = NULL; 5086 dst->lockstate = src->lockstate; 5087 } 5088 5089 5090 /* 5091 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5092 */ 5093 static int 5094 parse_libdir(const char *str) 5095 { 5096 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5097 const char *orig; 5098 int fd; 5099 char c; 5100 5101 orig = str; 5102 fd = 0; 5103 for (c = *str; c != '\0'; c = *++str) { 5104 if (c < '0' || c > '9') 5105 return (-1); 5106 5107 fd *= RADIX; 5108 fd += c - '0'; 5109 } 5110 5111 /* Make sure we actually parsed something. */ 5112 if (str == orig) { 5113 _rtld_error("failed to parse directory FD from '%s'", str); 5114 return (-1); 5115 } 5116 return (fd); 5117 } 5118 5119 /* 5120 * Overrides for libc_pic-provided functions. 5121 */ 5122 5123 int 5124 __getosreldate(void) 5125 { 5126 size_t len; 5127 int oid[2]; 5128 int error, osrel; 5129 5130 if (osreldate != 0) 5131 return (osreldate); 5132 5133 oid[0] = CTL_KERN; 5134 oid[1] = KERN_OSRELDATE; 5135 osrel = 0; 5136 len = sizeof(osrel); 5137 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5138 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5139 osreldate = osrel; 5140 return (osreldate); 5141 } 5142 5143 void 5144 exit(int status) 5145 { 5146 5147 _exit(status); 5148 } 5149 5150 void (*__cleanup)(void); 5151 int __isthreaded = 0; 5152 int _thread_autoinit_dummy_decl = 1; 5153 5154 /* 5155 * No unresolved symbols for rtld. 5156 */ 5157 void 5158 __pthread_cxa_finalize(struct dl_phdr_info *a) 5159 { 5160 } 5161 5162 void 5163 __stack_chk_fail(void) 5164 { 5165 5166 _rtld_error("stack overflow detected; terminated"); 5167 rtld_die(); 5168 } 5169 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5170 5171 void 5172 __chk_fail(void) 5173 { 5174 5175 _rtld_error("buffer overflow detected; terminated"); 5176 rtld_die(); 5177 } 5178 5179 const char * 5180 rtld_strerror(int errnum) 5181 { 5182 5183 if (errnum < 0 || errnum >= sys_nerr) 5184 return ("Unknown error"); 5185 return (sys_errlist[errnum]); 5186 } 5187