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