1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 7 * Copyright 2012 John Marino <draco@marino.st>. 8 * Copyright 2014-2017 The FreeBSD Foundation 9 * All rights reserved. 10 * 11 * Portions of this software were developed by Konstantin Belousov 12 * under sponsorship from the FreeBSD Foundation. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 35 /* 36 * Dynamic linker for ELF. 37 * 38 * John Polstra <jdp@polstra.com>. 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/mount.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 #include <sys/sysctl.h> 49 #include <sys/uio.h> 50 #include <sys/utsname.h> 51 #include <sys/ktrace.h> 52 53 #include <dlfcn.h> 54 #include <err.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <stdarg.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <unistd.h> 62 63 #include "debug.h" 64 #include "rtld.h" 65 #include "libmap.h" 66 #include "rtld_paths.h" 67 #include "rtld_tls.h" 68 #include "rtld_printf.h" 69 #include "rtld_malloc.h" 70 #include "rtld_utrace.h" 71 #include "notes.h" 72 #include "rtld_libc.h" 73 74 /* Types. */ 75 typedef void (*func_ptr_type)(void); 76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 77 78 79 /* Variables that cannot be static: */ 80 extern struct r_debug r_debug; /* For GDB */ 81 extern int _thread_autoinit_dummy_decl; 82 extern void (*__cleanup)(void); 83 84 struct dlerror_save { 85 int seen; 86 char *msg; 87 }; 88 89 /* 90 * Function declarations. 91 */ 92 static const char *basename(const char *); 93 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 94 const Elf_Dyn **, const Elf_Dyn **); 95 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 96 const Elf_Dyn *); 97 static bool digest_dynamic(Obj_Entry *, int); 98 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 99 static void distribute_static_tls(Objlist *, RtldLockState *); 100 static Obj_Entry *dlcheck(void *); 101 static int dlclose_locked(void *, RtldLockState *); 102 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 103 int lo_flags, int mode, RtldLockState *lockstate); 104 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 105 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 106 static bool donelist_check(DoneList *, const Obj_Entry *); 107 static void dump_auxv(Elf_Auxinfo **aux_info); 108 static void errmsg_restore(struct dlerror_save *); 109 static struct dlerror_save *errmsg_save(void); 110 static void *fill_search_info(const char *, size_t, void *); 111 static char *find_library(const char *, const Obj_Entry *, int *); 112 static const char *gethints(bool); 113 static void hold_object(Obj_Entry *); 114 static void unhold_object(Obj_Entry *); 115 static void init_dag(Obj_Entry *); 116 static void init_marker(Obj_Entry *); 117 static void init_pagesizes(Elf_Auxinfo **aux_info); 118 static void init_rtld(caddr_t, Elf_Auxinfo **); 119 static void initlist_add_neededs(Needed_Entry *, Objlist *); 120 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 121 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 122 static void linkmap_add(Obj_Entry *); 123 static void linkmap_delete(Obj_Entry *); 124 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 125 static void unload_filtees(Obj_Entry *, RtldLockState *); 126 static int load_needed_objects(Obj_Entry *, int); 127 static int load_preload_objects(const char *, bool); 128 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 129 static void map_stacks_exec(RtldLockState *); 130 static int obj_disable_relro(Obj_Entry *); 131 static int obj_enforce_relro(Obj_Entry *); 132 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 133 static void objlist_call_init(Objlist *, RtldLockState *); 134 static void objlist_clear(Objlist *); 135 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 136 static void objlist_init(Objlist *); 137 static void objlist_push_head(Objlist *, Obj_Entry *); 138 static void objlist_push_tail(Objlist *, Obj_Entry *); 139 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 140 static void objlist_remove(Objlist *, Obj_Entry *); 141 static int open_binary_fd(const char *argv0, bool search_in_path, 142 const char **binpath_res); 143 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 144 const char **argv0, bool *dir_ignore); 145 static int parse_integer(const char *); 146 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 147 static void print_usage(const char *argv0); 148 static void release_object(Obj_Entry *); 149 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 150 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 151 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 152 int flags, RtldLockState *lockstate); 153 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 154 RtldLockState *); 155 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 156 static int rtld_dirname(const char *, char *); 157 static int rtld_dirname_abs(const char *, char *); 158 static void *rtld_dlopen(const char *name, int fd, int mode); 159 static void rtld_exit(void); 160 static void rtld_nop_exit(void); 161 static char *search_library_path(const char *, const char *, const char *, 162 int *); 163 static char *search_library_pathfds(const char *, const char *, int *); 164 static const void **get_program_var_addr(const char *, RtldLockState *); 165 static void set_program_var(const char *, const void *); 166 static int symlook_default(SymLook *, const Obj_Entry *refobj); 167 static int symlook_global(SymLook *, DoneList *); 168 static void symlook_init_from_req(SymLook *, const SymLook *); 169 static int symlook_list(SymLook *, const Objlist *, DoneList *); 170 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 171 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 172 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 173 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline; 174 static void trace_loaded_objects(Obj_Entry *); 175 static void unlink_object(Obj_Entry *); 176 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 177 static void unref_dag(Obj_Entry *); 178 static void ref_dag(Obj_Entry *); 179 static char *origin_subst_one(Obj_Entry *, char *, const char *, 180 const char *, bool); 181 static char *origin_subst(Obj_Entry *, const char *); 182 static bool obj_resolve_origin(Obj_Entry *obj); 183 static void preinit_main(void); 184 static int rtld_verify_versions(const Objlist *); 185 static int rtld_verify_object_versions(Obj_Entry *); 186 static void object_add_name(Obj_Entry *, const char *); 187 static int object_match_name(const Obj_Entry *, const char *); 188 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 189 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 190 struct dl_phdr_info *phdr_info); 191 static uint32_t gnu_hash(const char *); 192 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 193 const unsigned long); 194 195 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 196 void _r_debug_postinit(struct link_map *) __noinline __exported; 197 198 int __sys_openat(int, const char *, int, ...); 199 200 /* 201 * Data declarations. 202 */ 203 struct r_debug r_debug __exported; /* for GDB; */ 204 static bool libmap_disable; /* Disable libmap */ 205 static bool ld_loadfltr; /* Immediate filters processing */ 206 static const char *libmap_override;/* Maps to use in addition to libmap.conf */ 207 static bool trust; /* False for setuid and setgid programs */ 208 static bool dangerous_ld_env; /* True if environment variables have been 209 used to affect the libraries loaded */ 210 bool ld_bind_not; /* Disable PLT update */ 211 static const char *ld_bind_now; /* Environment variable for immediate binding */ 212 static const char *ld_debug; /* Environment variable for debugging */ 213 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides 214 weak definition */ 215 static const char *ld_library_path;/* Environment variable for search path */ 216 static const char *ld_library_dirs;/* Environment variable for library descriptors */ 217 static const char *ld_preload; /* Environment variable for libraries to 218 load first */ 219 static const char *ld_preload_fds;/* Environment variable for libraries represented by 220 descriptors */ 221 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 222 static const char *ld_tracing; /* Called from ldd to print libs */ 223 static const char *ld_utrace; /* Use utrace() to log events. */ 224 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 225 static Obj_Entry *obj_main; /* The main program shared object */ 226 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 227 static unsigned int obj_count; /* Number of objects in obj_list */ 228 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 229 230 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 231 STAILQ_HEAD_INITIALIZER(list_global); 232 static Objlist list_main = /* Objects loaded at program startup */ 233 STAILQ_HEAD_INITIALIZER(list_main); 234 static Objlist list_fini = /* Objects needing fini() calls */ 235 STAILQ_HEAD_INITIALIZER(list_fini); 236 237 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 238 239 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 240 241 extern Elf_Dyn _DYNAMIC; 242 #pragma weak _DYNAMIC 243 244 int dlclose(void *) __exported; 245 char *dlerror(void) __exported; 246 void *dlopen(const char *, int) __exported; 247 void *fdlopen(int, int) __exported; 248 void *dlsym(void *, const char *) __exported; 249 dlfunc_t dlfunc(void *, const char *) __exported; 250 void *dlvsym(void *, const char *, const char *) __exported; 251 int dladdr(const void *, Dl_info *) __exported; 252 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 253 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 254 int dlinfo(void *, int , void *) __exported; 255 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 256 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 257 int _rtld_get_stack_prot(void) __exported; 258 int _rtld_is_dlopened(void *) __exported; 259 void _rtld_error(const char *, ...) __exported; 260 261 /* Only here to fix -Wmissing-prototypes warnings */ 262 int __getosreldate(void); 263 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 264 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 265 266 267 int npagesizes; 268 static int osreldate; 269 size_t *pagesizes; 270 271 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 272 static int max_stack_flags; 273 274 /* 275 * Global declarations normally provided by crt1. The dynamic linker is 276 * not built with crt1, so we have to provide them ourselves. 277 */ 278 char *__progname; 279 char **environ; 280 281 /* 282 * Used to pass argc, argv to init functions. 283 */ 284 int main_argc; 285 char **main_argv; 286 287 /* 288 * Globals to control TLS allocation. 289 */ 290 size_t tls_last_offset; /* Static TLS offset of last module */ 291 size_t tls_last_size; /* Static TLS size of last module */ 292 size_t tls_static_space; /* Static TLS space allocated */ 293 static size_t tls_static_max_align; 294 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 295 int tls_max_index = 1; /* Largest module index allocated */ 296 297 static bool ld_library_path_rpath = false; 298 bool ld_fast_sigblock = false; 299 300 /* 301 * Globals for path names, and such 302 */ 303 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 304 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 305 const char *ld_path_rtld = _PATH_RTLD; 306 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 307 const char *ld_env_prefix = LD_; 308 309 static void (*rtld_exit_ptr)(void); 310 311 /* 312 * Fill in a DoneList with an allocation large enough to hold all of 313 * the currently-loaded objects. Keep this as a macro since it calls 314 * alloca and we want that to occur within the scope of the caller. 315 */ 316 #define donelist_init(dlp) \ 317 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 318 assert((dlp)->objs != NULL), \ 319 (dlp)->num_alloc = obj_count, \ 320 (dlp)->num_used = 0) 321 322 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 323 if (ld_utrace != NULL) \ 324 ld_utrace_log(e, h, mb, ms, r, n); \ 325 } while (0) 326 327 static void 328 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 329 int refcnt, const char *name) 330 { 331 struct utrace_rtld ut; 332 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 333 334 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 335 ut.event = event; 336 ut.handle = handle; 337 ut.mapbase = mapbase; 338 ut.mapsize = mapsize; 339 ut.refcnt = refcnt; 340 bzero(ut.name, sizeof(ut.name)); 341 if (name) 342 strlcpy(ut.name, name, sizeof(ut.name)); 343 utrace(&ut, sizeof(ut)); 344 } 345 346 enum { 347 LD_BIND_NOW = 0, 348 LD_PRELOAD, 349 LD_LIBMAP, 350 LD_LIBRARY_PATH, 351 LD_LIBRARY_PATH_FDS, 352 LD_LIBMAP_DISABLE, 353 LD_BIND_NOT, 354 LD_DEBUG, 355 LD_ELF_HINTS_PATH, 356 LD_LOADFLTR, 357 LD_LIBRARY_PATH_RPATH, 358 LD_PRELOAD_FDS, 359 LD_DYNAMIC_WEAK, 360 LD_TRACE_LOADED_OBJECTS, 361 LD_UTRACE, 362 LD_DUMP_REL_PRE, 363 LD_DUMP_REL_POST, 364 LD_TRACE_LOADED_OBJECTS_PROGNAME, 365 LD_TRACE_LOADED_OBJECTS_FMT1, 366 LD_TRACE_LOADED_OBJECTS_FMT2, 367 LD_TRACE_LOADED_OBJECTS_ALL, 368 LD_SHOW_AUXV, 369 }; 370 371 struct ld_env_var_desc { 372 const char * const n; 373 const char *val; 374 const bool unsecure; 375 }; 376 #define LD_ENV_DESC(var, unsec) \ 377 [LD_##var] = { .n = #var, .unsecure = unsec } 378 379 static struct ld_env_var_desc ld_env_vars[] = { 380 LD_ENV_DESC(BIND_NOW, false), 381 LD_ENV_DESC(PRELOAD, true), 382 LD_ENV_DESC(LIBMAP, true), 383 LD_ENV_DESC(LIBRARY_PATH, true), 384 LD_ENV_DESC(LIBRARY_PATH_FDS, true), 385 LD_ENV_DESC(LIBMAP_DISABLE, true), 386 LD_ENV_DESC(BIND_NOT, true), 387 LD_ENV_DESC(DEBUG, true), 388 LD_ENV_DESC(ELF_HINTS_PATH, true), 389 LD_ENV_DESC(LOADFLTR, true), 390 LD_ENV_DESC(LIBRARY_PATH_RPATH, true), 391 LD_ENV_DESC(PRELOAD_FDS, true), 392 LD_ENV_DESC(DYNAMIC_WEAK, true), 393 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), 394 LD_ENV_DESC(UTRACE, false), 395 LD_ENV_DESC(DUMP_REL_PRE, false), 396 LD_ENV_DESC(DUMP_REL_POST, false), 397 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), 398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), 399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), 400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), 401 LD_ENV_DESC(SHOW_AUXV, false), 402 }; 403 404 static const char * 405 ld_get_env_var(int idx) 406 { 407 return (ld_env_vars[idx].val); 408 } 409 410 static const char * 411 rtld_get_env_val(char **env, const char *name, size_t name_len) 412 { 413 char **m, *n, *v; 414 415 for (m = env; *m != NULL; m++) { 416 n = *m; 417 v = strchr(n, '='); 418 if (v == NULL) { 419 /* corrupt environment? */ 420 continue; 421 } 422 if (v - n == (ptrdiff_t)name_len && 423 strncmp(name, n, name_len) == 0) 424 return (v + 1); 425 } 426 return (NULL); 427 } 428 429 static void 430 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) 431 { 432 struct ld_env_var_desc *lvd; 433 size_t prefix_len, nlen; 434 char **m, *n, *v; 435 int i; 436 437 prefix_len = strlen(env_prefix); 438 for (m = env; *m != NULL; m++) { 439 n = *m; 440 if (strncmp(env_prefix, n, prefix_len) != 0) { 441 /* Not a rtld environment variable. */ 442 continue; 443 } 444 n += prefix_len; 445 v = strchr(n, '='); 446 if (v == NULL) { 447 /* corrupt environment? */ 448 continue; 449 } 450 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 451 lvd = &ld_env_vars[i]; 452 if (lvd->val != NULL) { 453 /* Saw higher-priority variable name already. */ 454 continue; 455 } 456 nlen = strlen(lvd->n); 457 if (v - n == (ptrdiff_t)nlen && 458 strncmp(lvd->n, n, nlen) == 0) { 459 lvd->val = v + 1; 460 break; 461 } 462 } 463 } 464 } 465 466 static void 467 rtld_init_env_vars(char **env) 468 { 469 rtld_init_env_vars_for_prefix(env, ld_env_prefix); 470 } 471 472 static void 473 set_ld_elf_hints_path(void) 474 { 475 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) 476 ld_elf_hints_path = ld_elf_hints_default; 477 } 478 479 /* 480 * Main entry point for dynamic linking. The first argument is the 481 * stack pointer. The stack is expected to be laid out as described 482 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 483 * Specifically, the stack pointer points to a word containing 484 * ARGC. Following that in the stack is a null-terminated sequence 485 * of pointers to argument strings. Then comes a null-terminated 486 * sequence of pointers to environment strings. Finally, there is a 487 * sequence of "auxiliary vector" entries. 488 * 489 * The second argument points to a place to store the dynamic linker's 490 * exit procedure pointer and the third to a place to store the main 491 * program's object. 492 * 493 * The return value is the main program's entry point. 494 */ 495 func_ptr_type 496 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 497 { 498 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 499 Objlist_Entry *entry; 500 Obj_Entry *last_interposer, *obj, *preload_tail; 501 const Elf_Phdr *phdr; 502 Objlist initlist; 503 RtldLockState lockstate; 504 struct stat st; 505 Elf_Addr *argcp; 506 char **argv, **env, **envp, *kexecpath; 507 const char *argv0, *binpath, *library_path_rpath; 508 struct ld_env_var_desc *lvd; 509 caddr_t imgentry; 510 char buf[MAXPATHLEN]; 511 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 512 size_t sz; 513 #ifdef __powerpc__ 514 int old_auxv_format = 1; 515 #endif 516 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; 517 518 /* 519 * On entry, the dynamic linker itself has not been relocated yet. 520 * Be very careful not to reference any global data until after 521 * init_rtld has returned. It is OK to reference file-scope statics 522 * and string constants, and to call static and global functions. 523 */ 524 525 /* Find the auxiliary vector on the stack. */ 526 argcp = sp; 527 argc = *sp++; 528 argv = (char **) sp; 529 sp += argc + 1; /* Skip over arguments and NULL terminator */ 530 env = (char **) sp; 531 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 532 ; 533 aux = (Elf_Auxinfo *) sp; 534 535 /* Digest the auxiliary vector. */ 536 for (i = 0; i < AT_COUNT; i++) 537 aux_info[i] = NULL; 538 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 539 if (auxp->a_type < AT_COUNT) 540 aux_info[auxp->a_type] = auxp; 541 #ifdef __powerpc__ 542 if (auxp->a_type == 23) /* AT_STACKPROT */ 543 old_auxv_format = 0; 544 #endif 545 } 546 547 #ifdef __powerpc__ 548 if (old_auxv_format) { 549 /* Remap from old-style auxv numbers. */ 550 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 551 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 552 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 553 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 554 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 555 aux_info[13] = NULL; /* AT_GID */ 556 557 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 558 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 559 aux_info[16] = aux_info[14]; /* AT_CANARY */ 560 aux_info[14] = NULL; /* AT_EGID */ 561 } 562 #endif 563 564 /* Initialize and relocate ourselves. */ 565 assert(aux_info[AT_BASE] != NULL); 566 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 567 568 dlerror_dflt_init(); 569 570 __progname = obj_rtld.path; 571 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 572 environ = env; 573 main_argc = argc; 574 main_argv = argv; 575 576 if (aux_info[AT_BSDFLAGS] != NULL && 577 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 578 ld_fast_sigblock = true; 579 580 trust = !issetugid(); 581 direct_exec = false; 582 583 md_abi_variant_hook(aux_info); 584 rtld_init_env_vars(env); 585 586 fd = -1; 587 if (aux_info[AT_EXECFD] != NULL) { 588 fd = aux_info[AT_EXECFD]->a_un.a_val; 589 } else { 590 assert(aux_info[AT_PHDR] != NULL); 591 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 592 if (phdr == obj_rtld.phdr) { 593 if (!trust) { 594 _rtld_error("Tainted process refusing to run binary %s", 595 argv0); 596 rtld_die(); 597 } 598 direct_exec = true; 599 600 dbg("opening main program in direct exec mode"); 601 if (argc >= 2) { 602 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, 603 &argv0, &dir_ignore); 604 explicit_fd = (fd != -1); 605 binpath = NULL; 606 if (!explicit_fd) 607 fd = open_binary_fd(argv0, search_in_path, &binpath); 608 if (fstat(fd, &st) == -1) { 609 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 610 explicit_fd ? "user-provided descriptor" : argv0, 611 rtld_strerror(errno)); 612 rtld_die(); 613 } 614 615 /* 616 * Rough emulation of the permission checks done by 617 * execve(2), only Unix DACs are checked, ACLs are 618 * ignored. Preserve the semantic of disabling owner 619 * to execute if owner x bit is cleared, even if 620 * others x bit is enabled. 621 * mmap(2) does not allow to mmap with PROT_EXEC if 622 * binary' file comes from noexec mount. We cannot 623 * set a text reference on the binary. 624 */ 625 dir_enable = false; 626 if (st.st_uid == geteuid()) { 627 if ((st.st_mode & S_IXUSR) != 0) 628 dir_enable = true; 629 } else if (st.st_gid == getegid()) { 630 if ((st.st_mode & S_IXGRP) != 0) 631 dir_enable = true; 632 } else if ((st.st_mode & S_IXOTH) != 0) { 633 dir_enable = true; 634 } 635 if (!dir_enable && !dir_ignore) { 636 _rtld_error("No execute permission for binary %s", 637 argv0); 638 rtld_die(); 639 } 640 641 /* 642 * For direct exec mode, argv[0] is the interpreter 643 * name, we must remove it and shift arguments left 644 * before invoking binary main. Since stack layout 645 * places environment pointers and aux vectors right 646 * after the terminating NULL, we must shift 647 * environment and aux as well. 648 */ 649 main_argc = argc - rtld_argc; 650 for (i = 0; i <= main_argc; i++) 651 argv[i] = argv[i + rtld_argc]; 652 *argcp -= rtld_argc; 653 environ = env = envp = argv + main_argc + 1; 654 dbg("move env from %p to %p", envp + rtld_argc, envp); 655 do { 656 *envp = *(envp + rtld_argc); 657 } while (*envp++ != NULL); 658 aux = auxp = (Elf_Auxinfo *)envp; 659 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 660 dbg("move aux from %p to %p", auxpf, aux); 661 /* XXXKIB insert place for AT_EXECPATH if not present */ 662 for (;; auxp++, auxpf++) { 663 *auxp = *auxpf; 664 if (auxp->a_type == AT_NULL) 665 break; 666 } 667 /* Since the auxiliary vector has moved, redigest it. */ 668 for (i = 0; i < AT_COUNT; i++) 669 aux_info[i] = NULL; 670 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 671 if (auxp->a_type < AT_COUNT) 672 aux_info[auxp->a_type] = auxp; 673 } 674 675 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 676 if (binpath == NULL) { 677 aux_info[AT_EXECPATH] = NULL; 678 } else { 679 if (aux_info[AT_EXECPATH] == NULL) { 680 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 681 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 682 } 683 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 684 binpath); 685 } 686 } else { 687 _rtld_error("No binary"); 688 rtld_die(); 689 } 690 } 691 } 692 693 ld_bind_now = ld_get_env_var(LD_BIND_NOW); 694 695 /* 696 * If the process is tainted, then we un-set the dangerous environment 697 * variables. The process will be marked as tainted until setuid(2) 698 * is called. If any child process calls setuid(2) we do not want any 699 * future processes to honor the potentially un-safe variables. 700 */ 701 if (!trust) { 702 for (i = 0; i < (int)nitems(ld_env_vars); i++) { 703 lvd = &ld_env_vars[i]; 704 if (lvd->unsecure) 705 lvd->val = NULL; 706 } 707 } 708 709 ld_debug = ld_get_env_var(LD_DEBUG); 710 if (ld_bind_now == NULL) 711 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL; 712 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; 713 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; 714 libmap_override = ld_get_env_var(LD_LIBMAP); 715 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); 716 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); 717 ld_preload = ld_get_env_var(LD_PRELOAD); 718 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); 719 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); 720 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; 721 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH); 722 if (library_path_rpath != NULL) { 723 if (library_path_rpath[0] == 'y' || 724 library_path_rpath[0] == 'Y' || 725 library_path_rpath[0] == '1') 726 ld_library_path_rpath = true; 727 else 728 ld_library_path_rpath = false; 729 } 730 dangerous_ld_env = libmap_disable || libmap_override != NULL || 731 ld_library_path != NULL || ld_preload != NULL || 732 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak; 733 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); 734 ld_utrace = ld_get_env_var(LD_UTRACE); 735 736 set_ld_elf_hints_path(); 737 if (ld_debug != NULL && *ld_debug != '\0') 738 debug = 1; 739 dbg("%s is initialized, base address = %p", __progname, 740 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 741 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 742 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 743 744 dbg("initializing thread locks"); 745 lockdflt_init(); 746 747 /* 748 * Load the main program, or process its program header if it is 749 * already loaded. 750 */ 751 if (fd != -1) { /* Load the main program. */ 752 dbg("loading main program"); 753 obj_main = map_object(fd, argv0, NULL); 754 close(fd); 755 if (obj_main == NULL) 756 rtld_die(); 757 max_stack_flags = obj_main->stack_flags; 758 } else { /* Main program already loaded. */ 759 dbg("processing main program's program header"); 760 assert(aux_info[AT_PHDR] != NULL); 761 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 762 assert(aux_info[AT_PHNUM] != NULL); 763 phnum = aux_info[AT_PHNUM]->a_un.a_val; 764 assert(aux_info[AT_PHENT] != NULL); 765 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 766 assert(aux_info[AT_ENTRY] != NULL); 767 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 768 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 769 rtld_die(); 770 } 771 772 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 773 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 774 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 775 if (kexecpath[0] == '/') 776 obj_main->path = kexecpath; 777 else if (getcwd(buf, sizeof(buf)) == NULL || 778 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 779 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 780 obj_main->path = xstrdup(argv0); 781 else 782 obj_main->path = xstrdup(buf); 783 } else { 784 dbg("No AT_EXECPATH or direct exec"); 785 obj_main->path = xstrdup(argv0); 786 } 787 dbg("obj_main path %s", obj_main->path); 788 obj_main->mainprog = true; 789 790 if (aux_info[AT_STACKPROT] != NULL && 791 aux_info[AT_STACKPROT]->a_un.a_val != 0) 792 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 793 794 #ifndef COMPAT_32BIT 795 /* 796 * Get the actual dynamic linker pathname from the executable if 797 * possible. (It should always be possible.) That ensures that 798 * gdb will find the right dynamic linker even if a non-standard 799 * one is being used. 800 */ 801 if (obj_main->interp != NULL && 802 strcmp(obj_main->interp, obj_rtld.path) != 0) { 803 free(obj_rtld.path); 804 obj_rtld.path = xstrdup(obj_main->interp); 805 __progname = obj_rtld.path; 806 } 807 #endif 808 809 if (!digest_dynamic(obj_main, 0)) 810 rtld_die(); 811 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 812 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 813 obj_main->dynsymcount); 814 815 linkmap_add(obj_main); 816 linkmap_add(&obj_rtld); 817 818 /* Link the main program into the list of objects. */ 819 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 820 obj_count++; 821 obj_loads++; 822 823 /* Initialize a fake symbol for resolving undefined weak references. */ 824 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 825 sym_zero.st_shndx = SHN_UNDEF; 826 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 827 828 if (!libmap_disable) 829 libmap_disable = (bool)lm_init(libmap_override); 830 831 dbg("loading LD_PRELOAD_FDS libraries"); 832 if (load_preload_objects(ld_preload_fds, true) == -1) 833 rtld_die(); 834 835 dbg("loading LD_PRELOAD libraries"); 836 if (load_preload_objects(ld_preload, false) == -1) 837 rtld_die(); 838 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 839 840 dbg("loading needed objects"); 841 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 842 0) == -1) 843 rtld_die(); 844 845 /* Make a list of all objects loaded at startup. */ 846 last_interposer = obj_main; 847 TAILQ_FOREACH(obj, &obj_list, next) { 848 if (obj->marker) 849 continue; 850 if (obj->z_interpose && obj != obj_main) { 851 objlist_put_after(&list_main, last_interposer, obj); 852 last_interposer = obj; 853 } else { 854 objlist_push_tail(&list_main, obj); 855 } 856 obj->refcount++; 857 } 858 859 dbg("checking for required versions"); 860 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 861 rtld_die(); 862 863 if (ld_get_env_var(LD_SHOW_AUXV) != NULL) 864 dump_auxv(aux_info); 865 866 if (ld_tracing) { /* We're done */ 867 trace_loaded_objects(obj_main); 868 exit(0); 869 } 870 871 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { 872 dump_relocations(obj_main); 873 exit (0); 874 } 875 876 /* 877 * Processing tls relocations requires having the tls offsets 878 * initialized. Prepare offsets before starting initial 879 * relocation processing. 880 */ 881 dbg("initializing initial thread local storage offsets"); 882 STAILQ_FOREACH(entry, &list_main, link) { 883 /* 884 * Allocate all the initial objects out of the static TLS 885 * block even if they didn't ask for it. 886 */ 887 allocate_tls_offset(entry->obj); 888 } 889 890 if (relocate_objects(obj_main, 891 ld_bind_now != NULL && *ld_bind_now != '\0', 892 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 893 rtld_die(); 894 895 dbg("doing copy relocations"); 896 if (do_copy_relocations(obj_main) == -1) 897 rtld_die(); 898 899 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { 900 dump_relocations(obj_main); 901 exit (0); 902 } 903 904 ifunc_init(aux); 905 906 /* 907 * Setup TLS for main thread. This must be done after the 908 * relocations are processed, since tls initialization section 909 * might be the subject for relocations. 910 */ 911 dbg("initializing initial thread local storage"); 912 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 913 914 dbg("initializing key program variables"); 915 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 916 set_program_var("environ", env); 917 set_program_var("__elf_aux_vector", aux); 918 919 /* Make a list of init functions to call. */ 920 objlist_init(&initlist); 921 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 922 preload_tail, &initlist); 923 924 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 925 926 map_stacks_exec(NULL); 927 928 if (!obj_main->crt_no_init) { 929 /* 930 * Make sure we don't call the main program's init and fini 931 * functions for binaries linked with old crt1 which calls 932 * _init itself. 933 */ 934 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 935 obj_main->preinit_array = obj_main->init_array = 936 obj_main->fini_array = (Elf_Addr)NULL; 937 } 938 939 if (direct_exec) { 940 /* Set osrel for direct-execed binary */ 941 mib[0] = CTL_KERN; 942 mib[1] = KERN_PROC; 943 mib[2] = KERN_PROC_OSREL; 944 mib[3] = getpid(); 945 osrel = obj_main->osrel; 946 sz = sizeof(old_osrel); 947 dbg("setting osrel to %d", osrel); 948 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 949 } 950 951 wlock_acquire(rtld_bind_lock, &lockstate); 952 953 dbg("resolving ifuncs"); 954 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 955 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 956 rtld_die(); 957 958 rtld_exit_ptr = rtld_exit; 959 if (obj_main->crt_no_init) 960 preinit_main(); 961 objlist_call_init(&initlist, &lockstate); 962 _r_debug_postinit(&obj_main->linkmap); 963 objlist_clear(&initlist); 964 dbg("loading filtees"); 965 TAILQ_FOREACH(obj, &obj_list, next) { 966 if (obj->marker) 967 continue; 968 if (ld_loadfltr || obj->z_loadfltr) 969 load_filtees(obj, 0, &lockstate); 970 } 971 972 dbg("enforcing main obj relro"); 973 if (obj_enforce_relro(obj_main) == -1) 974 rtld_die(); 975 976 lock_release(rtld_bind_lock, &lockstate); 977 978 dbg("transferring control to program entry point = %p", obj_main->entry); 979 980 /* Return the exit procedure and the program entry point. */ 981 *exit_proc = rtld_exit_ptr; 982 *objp = obj_main; 983 return ((func_ptr_type)obj_main->entry); 984 } 985 986 void * 987 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 988 { 989 void *ptr; 990 Elf_Addr target; 991 992 ptr = (void *)make_function_pointer(def, obj); 993 target = call_ifunc_resolver(ptr); 994 return ((void *)target); 995 } 996 997 /* 998 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 999 * Changes to this function should be applied there as well. 1000 */ 1001 Elf_Addr 1002 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 1003 { 1004 const Elf_Rel *rel; 1005 const Elf_Sym *def; 1006 const Obj_Entry *defobj; 1007 Elf_Addr *where; 1008 Elf_Addr target; 1009 RtldLockState lockstate; 1010 1011 rlock_acquire(rtld_bind_lock, &lockstate); 1012 if (sigsetjmp(lockstate.env, 0) != 0) 1013 lock_upgrade(rtld_bind_lock, &lockstate); 1014 if (obj->pltrel) 1015 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 1016 else 1017 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 1018 1019 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 1020 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 1021 NULL, &lockstate); 1022 if (def == NULL) 1023 rtld_die(); 1024 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 1025 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 1026 else 1027 target = (Elf_Addr)(defobj->relocbase + def->st_value); 1028 1029 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 1030 defobj->strtab + def->st_name, 1031 obj->path == NULL ? NULL : basename(obj->path), 1032 (void *)target, 1033 defobj->path == NULL ? NULL : basename(defobj->path)); 1034 1035 /* 1036 * Write the new contents for the jmpslot. Note that depending on 1037 * architecture, the value which we need to return back to the 1038 * lazy binding trampoline may or may not be the target 1039 * address. The value returned from reloc_jmpslot() is the value 1040 * that the trampoline needs. 1041 */ 1042 target = reloc_jmpslot(where, target, defobj, obj, rel); 1043 lock_release(rtld_bind_lock, &lockstate); 1044 return (target); 1045 } 1046 1047 /* 1048 * Error reporting function. Use it like printf. If formats the message 1049 * into a buffer, and sets things up so that the next call to dlerror() 1050 * will return the message. 1051 */ 1052 void 1053 _rtld_error(const char *fmt, ...) 1054 { 1055 va_list ap; 1056 1057 va_start(ap, fmt); 1058 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, 1059 fmt, ap); 1060 va_end(ap); 1061 *lockinfo.dlerror_seen() = 0; 1062 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); 1063 } 1064 1065 /* 1066 * Return a dynamically-allocated copy of the current error message, if any. 1067 */ 1068 static struct dlerror_save * 1069 errmsg_save(void) 1070 { 1071 struct dlerror_save *res; 1072 1073 res = xmalloc(sizeof(*res)); 1074 res->seen = *lockinfo.dlerror_seen(); 1075 if (res->seen == 0) 1076 res->msg = xstrdup(lockinfo.dlerror_loc()); 1077 return (res); 1078 } 1079 1080 /* 1081 * Restore the current error message from a copy which was previously saved 1082 * by errmsg_save(). The copy is freed. 1083 */ 1084 static void 1085 errmsg_restore(struct dlerror_save *saved_msg) 1086 { 1087 if (saved_msg == NULL || saved_msg->seen == 1) { 1088 *lockinfo.dlerror_seen() = 1; 1089 } else { 1090 *lockinfo.dlerror_seen() = 0; 1091 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, 1092 lockinfo.dlerror_loc_sz); 1093 free(saved_msg->msg); 1094 } 1095 free(saved_msg); 1096 } 1097 1098 static const char * 1099 basename(const char *name) 1100 { 1101 const char *p; 1102 1103 p = strrchr(name, '/'); 1104 return (p != NULL ? p + 1 : name); 1105 } 1106 1107 static struct utsname uts; 1108 1109 static char * 1110 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 1111 const char *subst, bool may_free) 1112 { 1113 char *p, *p1, *res, *resp; 1114 int subst_len, kw_len, subst_count, old_len, new_len; 1115 1116 kw_len = strlen(kw); 1117 1118 /* 1119 * First, count the number of the keyword occurrences, to 1120 * preallocate the final string. 1121 */ 1122 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 1123 p1 = strstr(p, kw); 1124 if (p1 == NULL) 1125 break; 1126 } 1127 1128 /* 1129 * If the keyword is not found, just return. 1130 * 1131 * Return non-substituted string if resolution failed. We 1132 * cannot do anything more reasonable, the failure mode of the 1133 * caller is unresolved library anyway. 1134 */ 1135 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1136 return (may_free ? real : xstrdup(real)); 1137 if (obj != NULL) 1138 subst = obj->origin_path; 1139 1140 /* 1141 * There is indeed something to substitute. Calculate the 1142 * length of the resulting string, and allocate it. 1143 */ 1144 subst_len = strlen(subst); 1145 old_len = strlen(real); 1146 new_len = old_len + (subst_len - kw_len) * subst_count; 1147 res = xmalloc(new_len + 1); 1148 1149 /* 1150 * Now, execute the substitution loop. 1151 */ 1152 for (p = real, resp = res, *resp = '\0';;) { 1153 p1 = strstr(p, kw); 1154 if (p1 != NULL) { 1155 /* Copy the prefix before keyword. */ 1156 memcpy(resp, p, p1 - p); 1157 resp += p1 - p; 1158 /* Keyword replacement. */ 1159 memcpy(resp, subst, subst_len); 1160 resp += subst_len; 1161 *resp = '\0'; 1162 p = p1 + kw_len; 1163 } else 1164 break; 1165 } 1166 1167 /* Copy to the end of string and finish. */ 1168 strcat(resp, p); 1169 if (may_free) 1170 free(real); 1171 return (res); 1172 } 1173 1174 static char * 1175 origin_subst(Obj_Entry *obj, const char *real) 1176 { 1177 char *res1, *res2, *res3, *res4; 1178 1179 if (obj == NULL || !trust) 1180 return (xstrdup(real)); 1181 if (uts.sysname[0] == '\0') { 1182 if (uname(&uts) != 0) { 1183 _rtld_error("utsname failed: %d", errno); 1184 return (NULL); 1185 } 1186 } 1187 /* __DECONST is safe here since without may_free real is unchanged */ 1188 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1189 false); 1190 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1191 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1192 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1193 return (res4); 1194 } 1195 1196 void 1197 rtld_die(void) 1198 { 1199 const char *msg = dlerror(); 1200 1201 if (msg == NULL) 1202 msg = "Fatal error"; 1203 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1204 rtld_fdputstr(STDERR_FILENO, msg); 1205 rtld_fdputchar(STDERR_FILENO, '\n'); 1206 _exit(1); 1207 } 1208 1209 /* 1210 * Process a shared object's DYNAMIC section, and save the important 1211 * information in its Obj_Entry structure. 1212 */ 1213 static void 1214 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1215 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1216 { 1217 const Elf_Dyn *dynp; 1218 Needed_Entry **needed_tail = &obj->needed; 1219 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1220 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1221 const Elf_Hashelt *hashtab; 1222 const Elf32_Word *hashval; 1223 Elf32_Word bkt, nmaskwords; 1224 int bloom_size32; 1225 int plttype = DT_REL; 1226 1227 *dyn_rpath = NULL; 1228 *dyn_soname = NULL; 1229 *dyn_runpath = NULL; 1230 1231 obj->bind_now = false; 1232 dynp = obj->dynamic; 1233 if (dynp == NULL) 1234 return; 1235 for (; dynp->d_tag != DT_NULL; dynp++) { 1236 switch (dynp->d_tag) { 1237 1238 case DT_REL: 1239 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1240 break; 1241 1242 case DT_RELSZ: 1243 obj->relsize = dynp->d_un.d_val; 1244 break; 1245 1246 case DT_RELENT: 1247 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1248 break; 1249 1250 case DT_JMPREL: 1251 obj->pltrel = (const Elf_Rel *) 1252 (obj->relocbase + dynp->d_un.d_ptr); 1253 break; 1254 1255 case DT_PLTRELSZ: 1256 obj->pltrelsize = dynp->d_un.d_val; 1257 break; 1258 1259 case DT_RELA: 1260 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1261 break; 1262 1263 case DT_RELASZ: 1264 obj->relasize = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_RELAENT: 1268 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1269 break; 1270 1271 case DT_RELR: 1272 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); 1273 break; 1274 1275 case DT_RELRSZ: 1276 obj->relrsize = dynp->d_un.d_val; 1277 break; 1278 1279 case DT_RELRENT: 1280 assert(dynp->d_un.d_val == sizeof(Elf_Relr)); 1281 break; 1282 1283 case DT_PLTREL: 1284 plttype = dynp->d_un.d_val; 1285 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1286 break; 1287 1288 case DT_SYMTAB: 1289 obj->symtab = (const Elf_Sym *) 1290 (obj->relocbase + dynp->d_un.d_ptr); 1291 break; 1292 1293 case DT_SYMENT: 1294 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1295 break; 1296 1297 case DT_STRTAB: 1298 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1299 break; 1300 1301 case DT_STRSZ: 1302 obj->strsize = dynp->d_un.d_val; 1303 break; 1304 1305 case DT_VERNEED: 1306 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1307 dynp->d_un.d_val); 1308 break; 1309 1310 case DT_VERNEEDNUM: 1311 obj->verneednum = dynp->d_un.d_val; 1312 break; 1313 1314 case DT_VERDEF: 1315 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1316 dynp->d_un.d_val); 1317 break; 1318 1319 case DT_VERDEFNUM: 1320 obj->verdefnum = dynp->d_un.d_val; 1321 break; 1322 1323 case DT_VERSYM: 1324 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1325 dynp->d_un.d_val); 1326 break; 1327 1328 case DT_HASH: 1329 { 1330 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1331 dynp->d_un.d_ptr); 1332 obj->nbuckets = hashtab[0]; 1333 obj->nchains = hashtab[1]; 1334 obj->buckets = hashtab + 2; 1335 obj->chains = obj->buckets + obj->nbuckets; 1336 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1337 obj->buckets != NULL; 1338 } 1339 break; 1340 1341 case DT_GNU_HASH: 1342 { 1343 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1344 dynp->d_un.d_ptr); 1345 obj->nbuckets_gnu = hashtab[0]; 1346 obj->symndx_gnu = hashtab[1]; 1347 nmaskwords = hashtab[2]; 1348 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1349 obj->maskwords_bm_gnu = nmaskwords - 1; 1350 obj->shift2_gnu = hashtab[3]; 1351 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1352 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1353 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1354 obj->symndx_gnu; 1355 /* Number of bitmask words is required to be power of 2 */ 1356 obj->valid_hash_gnu = powerof2(nmaskwords) && 1357 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1358 } 1359 break; 1360 1361 case DT_NEEDED: 1362 if (!obj->rtld) { 1363 Needed_Entry *nep = NEW(Needed_Entry); 1364 nep->name = dynp->d_un.d_val; 1365 nep->obj = NULL; 1366 nep->next = NULL; 1367 1368 *needed_tail = nep; 1369 needed_tail = &nep->next; 1370 } 1371 break; 1372 1373 case DT_FILTER: 1374 if (!obj->rtld) { 1375 Needed_Entry *nep = NEW(Needed_Entry); 1376 nep->name = dynp->d_un.d_val; 1377 nep->obj = NULL; 1378 nep->next = NULL; 1379 1380 *needed_filtees_tail = nep; 1381 needed_filtees_tail = &nep->next; 1382 1383 if (obj->linkmap.l_refname == NULL) 1384 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1385 } 1386 break; 1387 1388 case DT_AUXILIARY: 1389 if (!obj->rtld) { 1390 Needed_Entry *nep = NEW(Needed_Entry); 1391 nep->name = dynp->d_un.d_val; 1392 nep->obj = NULL; 1393 nep->next = NULL; 1394 1395 *needed_aux_filtees_tail = nep; 1396 needed_aux_filtees_tail = &nep->next; 1397 } 1398 break; 1399 1400 case DT_PLTGOT: 1401 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1402 break; 1403 1404 case DT_TEXTREL: 1405 obj->textrel = true; 1406 break; 1407 1408 case DT_SYMBOLIC: 1409 obj->symbolic = true; 1410 break; 1411 1412 case DT_RPATH: 1413 /* 1414 * We have to wait until later to process this, because we 1415 * might not have gotten the address of the string table yet. 1416 */ 1417 *dyn_rpath = dynp; 1418 break; 1419 1420 case DT_SONAME: 1421 *dyn_soname = dynp; 1422 break; 1423 1424 case DT_RUNPATH: 1425 *dyn_runpath = dynp; 1426 break; 1427 1428 case DT_INIT: 1429 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1430 break; 1431 1432 case DT_PREINIT_ARRAY: 1433 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1434 break; 1435 1436 case DT_PREINIT_ARRAYSZ: 1437 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1438 break; 1439 1440 case DT_INIT_ARRAY: 1441 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1442 break; 1443 1444 case DT_INIT_ARRAYSZ: 1445 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1446 break; 1447 1448 case DT_FINI: 1449 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1450 break; 1451 1452 case DT_FINI_ARRAY: 1453 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1454 break; 1455 1456 case DT_FINI_ARRAYSZ: 1457 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1458 break; 1459 1460 /* 1461 * Don't process DT_DEBUG on MIPS as the dynamic section 1462 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1463 */ 1464 1465 #ifndef __mips__ 1466 case DT_DEBUG: 1467 if (!early) 1468 dbg("Filling in DT_DEBUG entry"); 1469 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1470 break; 1471 #endif 1472 1473 case DT_FLAGS: 1474 if (dynp->d_un.d_val & DF_ORIGIN) 1475 obj->z_origin = true; 1476 if (dynp->d_un.d_val & DF_SYMBOLIC) 1477 obj->symbolic = true; 1478 if (dynp->d_un.d_val & DF_TEXTREL) 1479 obj->textrel = true; 1480 if (dynp->d_un.d_val & DF_BIND_NOW) 1481 obj->bind_now = true; 1482 if (dynp->d_un.d_val & DF_STATIC_TLS) 1483 obj->static_tls = true; 1484 break; 1485 #ifdef __mips__ 1486 case DT_MIPS_LOCAL_GOTNO: 1487 obj->local_gotno = dynp->d_un.d_val; 1488 break; 1489 1490 case DT_MIPS_SYMTABNO: 1491 obj->symtabno = dynp->d_un.d_val; 1492 break; 1493 1494 case DT_MIPS_GOTSYM: 1495 obj->gotsym = dynp->d_un.d_val; 1496 break; 1497 1498 case DT_MIPS_RLD_MAP: 1499 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1500 break; 1501 1502 case DT_MIPS_RLD_MAP_REL: 1503 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1504 // section relative to the address of the tag itself. 1505 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1506 (Elf_Addr) &r_debug; 1507 break; 1508 1509 case DT_MIPS_PLTGOT: 1510 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1511 dynp->d_un.d_ptr); 1512 break; 1513 1514 #endif 1515 1516 #ifdef __powerpc__ 1517 #ifdef __powerpc64__ 1518 case DT_PPC64_GLINK: 1519 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1520 break; 1521 #else 1522 case DT_PPC_GOT: 1523 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1524 break; 1525 #endif 1526 #endif 1527 1528 case DT_FLAGS_1: 1529 if (dynp->d_un.d_val & DF_1_NOOPEN) 1530 obj->z_noopen = true; 1531 if (dynp->d_un.d_val & DF_1_ORIGIN) 1532 obj->z_origin = true; 1533 if (dynp->d_un.d_val & DF_1_GLOBAL) 1534 obj->z_global = true; 1535 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1536 obj->bind_now = true; 1537 if (dynp->d_un.d_val & DF_1_NODELETE) 1538 obj->z_nodelete = true; 1539 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1540 obj->z_loadfltr = true; 1541 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1542 obj->z_interpose = true; 1543 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1544 obj->z_nodeflib = true; 1545 if (dynp->d_un.d_val & DF_1_PIE) 1546 obj->z_pie = true; 1547 break; 1548 1549 default: 1550 if (!early) { 1551 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1552 (long)dynp->d_tag); 1553 } 1554 break; 1555 } 1556 } 1557 1558 obj->traced = false; 1559 1560 if (plttype == DT_RELA) { 1561 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1562 obj->pltrel = NULL; 1563 obj->pltrelasize = obj->pltrelsize; 1564 obj->pltrelsize = 0; 1565 } 1566 1567 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1568 if (obj->valid_hash_sysv) 1569 obj->dynsymcount = obj->nchains; 1570 else if (obj->valid_hash_gnu) { 1571 obj->dynsymcount = 0; 1572 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1573 if (obj->buckets_gnu[bkt] == 0) 1574 continue; 1575 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1576 do 1577 obj->dynsymcount++; 1578 while ((*hashval++ & 1u) == 0); 1579 } 1580 obj->dynsymcount += obj->symndx_gnu; 1581 } 1582 1583 if (obj->linkmap.l_refname != NULL) 1584 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1585 linkmap.l_refname; 1586 } 1587 1588 static bool 1589 obj_resolve_origin(Obj_Entry *obj) 1590 { 1591 1592 if (obj->origin_path != NULL) 1593 return (true); 1594 obj->origin_path = xmalloc(PATH_MAX); 1595 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1596 } 1597 1598 static bool 1599 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1600 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1601 { 1602 1603 if (obj->z_origin && !obj_resolve_origin(obj)) 1604 return (false); 1605 1606 if (dyn_runpath != NULL) { 1607 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1608 obj->runpath = origin_subst(obj, obj->runpath); 1609 } else if (dyn_rpath != NULL) { 1610 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1611 obj->rpath = origin_subst(obj, obj->rpath); 1612 } 1613 if (dyn_soname != NULL) 1614 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1615 return (true); 1616 } 1617 1618 static bool 1619 digest_dynamic(Obj_Entry *obj, int early) 1620 { 1621 const Elf_Dyn *dyn_rpath; 1622 const Elf_Dyn *dyn_soname; 1623 const Elf_Dyn *dyn_runpath; 1624 1625 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1626 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1627 } 1628 1629 /* 1630 * Process a shared object's program header. This is used only for the 1631 * main program, when the kernel has already loaded the main program 1632 * into memory before calling the dynamic linker. It creates and 1633 * returns an Obj_Entry structure. 1634 */ 1635 static Obj_Entry * 1636 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1637 { 1638 Obj_Entry *obj; 1639 const Elf_Phdr *phlimit = phdr + phnum; 1640 const Elf_Phdr *ph; 1641 Elf_Addr note_start, note_end; 1642 int nsegs = 0; 1643 1644 obj = obj_new(); 1645 for (ph = phdr; ph < phlimit; ph++) { 1646 if (ph->p_type != PT_PHDR) 1647 continue; 1648 1649 obj->phdr = phdr; 1650 obj->phsize = ph->p_memsz; 1651 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1652 break; 1653 } 1654 1655 obj->stack_flags = PF_X | PF_R | PF_W; 1656 1657 for (ph = phdr; ph < phlimit; ph++) { 1658 switch (ph->p_type) { 1659 1660 case PT_INTERP: 1661 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1662 break; 1663 1664 case PT_LOAD: 1665 if (nsegs == 0) { /* First load segment */ 1666 obj->vaddrbase = trunc_page(ph->p_vaddr); 1667 obj->mapbase = obj->vaddrbase + obj->relocbase; 1668 } else { /* Last load segment */ 1669 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1670 obj->vaddrbase; 1671 } 1672 nsegs++; 1673 break; 1674 1675 case PT_DYNAMIC: 1676 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1677 break; 1678 1679 case PT_TLS: 1680 obj->tlsindex = 1; 1681 obj->tlssize = ph->p_memsz; 1682 obj->tlsalign = ph->p_align; 1683 obj->tlsinitsize = ph->p_filesz; 1684 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1685 obj->tlspoffset = ph->p_offset; 1686 break; 1687 1688 case PT_GNU_STACK: 1689 obj->stack_flags = ph->p_flags; 1690 break; 1691 1692 case PT_GNU_RELRO: 1693 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1694 obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - 1695 trunc_page(ph->p_vaddr); 1696 break; 1697 1698 case PT_NOTE: 1699 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1700 note_end = note_start + ph->p_filesz; 1701 digest_notes(obj, note_start, note_end); 1702 break; 1703 } 1704 } 1705 if (nsegs < 1) { 1706 _rtld_error("%s: too few PT_LOAD segments", path); 1707 return (NULL); 1708 } 1709 1710 obj->entry = entry; 1711 return (obj); 1712 } 1713 1714 void 1715 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1716 { 1717 const Elf_Note *note; 1718 const char *note_name; 1719 uintptr_t p; 1720 1721 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1722 note = (const Elf_Note *)((const char *)(note + 1) + 1723 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1724 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1725 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1726 note->n_descsz != sizeof(int32_t)) 1727 continue; 1728 if (note->n_type != NT_FREEBSD_ABI_TAG && 1729 note->n_type != NT_FREEBSD_FEATURE_CTL && 1730 note->n_type != NT_FREEBSD_NOINIT_TAG) 1731 continue; 1732 note_name = (const char *)(note + 1); 1733 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1734 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1735 continue; 1736 switch (note->n_type) { 1737 case NT_FREEBSD_ABI_TAG: 1738 /* FreeBSD osrel note */ 1739 p = (uintptr_t)(note + 1); 1740 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1741 obj->osrel = *(const int32_t *)(p); 1742 dbg("note osrel %d", obj->osrel); 1743 break; 1744 case NT_FREEBSD_FEATURE_CTL: 1745 /* FreeBSD ABI feature control note */ 1746 p = (uintptr_t)(note + 1); 1747 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1748 obj->fctl0 = *(const uint32_t *)(p); 1749 dbg("note fctl0 %#x", obj->fctl0); 1750 break; 1751 case NT_FREEBSD_NOINIT_TAG: 1752 /* FreeBSD 'crt does not call init' note */ 1753 obj->crt_no_init = true; 1754 dbg("note crt_no_init"); 1755 break; 1756 } 1757 } 1758 } 1759 1760 static Obj_Entry * 1761 dlcheck(void *handle) 1762 { 1763 Obj_Entry *obj; 1764 1765 TAILQ_FOREACH(obj, &obj_list, next) { 1766 if (obj == (Obj_Entry *) handle) 1767 break; 1768 } 1769 1770 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1771 _rtld_error("Invalid shared object handle %p", handle); 1772 return (NULL); 1773 } 1774 return (obj); 1775 } 1776 1777 /* 1778 * If the given object is already in the donelist, return true. Otherwise 1779 * add the object to the list and return false. 1780 */ 1781 static bool 1782 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1783 { 1784 unsigned int i; 1785 1786 for (i = 0; i < dlp->num_used; i++) 1787 if (dlp->objs[i] == obj) 1788 return (true); 1789 /* 1790 * Our donelist allocation should always be sufficient. But if 1791 * our threads locking isn't working properly, more shared objects 1792 * could have been loaded since we allocated the list. That should 1793 * never happen, but we'll handle it properly just in case it does. 1794 */ 1795 if (dlp->num_used < dlp->num_alloc) 1796 dlp->objs[dlp->num_used++] = obj; 1797 return (false); 1798 } 1799 1800 /* 1801 * Hash function for symbol table lookup. Don't even think about changing 1802 * this. It is specified by the System V ABI. 1803 */ 1804 unsigned long 1805 elf_hash(const char *name) 1806 { 1807 const unsigned char *p = (const unsigned char *) name; 1808 unsigned long h = 0; 1809 unsigned long g; 1810 1811 while (*p != '\0') { 1812 h = (h << 4) + *p++; 1813 if ((g = h & 0xf0000000) != 0) 1814 h ^= g >> 24; 1815 h &= ~g; 1816 } 1817 return (h); 1818 } 1819 1820 /* 1821 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1822 * unsigned in case it's implemented with a wider type. 1823 */ 1824 static uint32_t 1825 gnu_hash(const char *s) 1826 { 1827 uint32_t h; 1828 unsigned char c; 1829 1830 h = 5381; 1831 for (c = *s; c != '\0'; c = *++s) 1832 h = h * 33 + c; 1833 return (h & 0xffffffff); 1834 } 1835 1836 1837 /* 1838 * Find the library with the given name, and return its full pathname. 1839 * The returned string is dynamically allocated. Generates an error 1840 * message and returns NULL if the library cannot be found. 1841 * 1842 * If the second argument is non-NULL, then it refers to an already- 1843 * loaded shared object, whose library search path will be searched. 1844 * 1845 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1846 * descriptor (which is close-on-exec) will be passed out via the third 1847 * argument. 1848 * 1849 * The search order is: 1850 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1851 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1852 * LD_LIBRARY_PATH 1853 * DT_RUNPATH in the referencing file 1854 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1855 * from list) 1856 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1857 * 1858 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1859 */ 1860 static char * 1861 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1862 { 1863 char *pathname, *refobj_path; 1864 const char *name; 1865 bool nodeflib, objgiven; 1866 1867 objgiven = refobj != NULL; 1868 1869 if (libmap_disable || !objgiven || 1870 (name = lm_find(refobj->path, xname)) == NULL) 1871 name = xname; 1872 1873 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1874 if (name[0] != '/' && !trust) { 1875 _rtld_error("Absolute pathname required " 1876 "for shared object \"%s\"", name); 1877 return (NULL); 1878 } 1879 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1880 __DECONST(char *, name))); 1881 } 1882 1883 dbg(" Searching for \"%s\"", name); 1884 refobj_path = objgiven ? refobj->path : NULL; 1885 1886 /* 1887 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1888 * back to pre-conforming behaviour if user requested so with 1889 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1890 * nodeflib. 1891 */ 1892 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1893 pathname = search_library_path(name, ld_library_path, 1894 refobj_path, fdp); 1895 if (pathname != NULL) 1896 return (pathname); 1897 if (refobj != NULL) { 1898 pathname = search_library_path(name, refobj->rpath, 1899 refobj_path, fdp); 1900 if (pathname != NULL) 1901 return (pathname); 1902 } 1903 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1904 if (pathname != NULL) 1905 return (pathname); 1906 pathname = search_library_path(name, gethints(false), 1907 refobj_path, fdp); 1908 if (pathname != NULL) 1909 return (pathname); 1910 pathname = search_library_path(name, ld_standard_library_path, 1911 refobj_path, fdp); 1912 if (pathname != NULL) 1913 return (pathname); 1914 } else { 1915 nodeflib = objgiven ? refobj->z_nodeflib : false; 1916 if (objgiven) { 1917 pathname = search_library_path(name, refobj->rpath, 1918 refobj->path, fdp); 1919 if (pathname != NULL) 1920 return (pathname); 1921 } 1922 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1923 pathname = search_library_path(name, obj_main->rpath, 1924 refobj_path, fdp); 1925 if (pathname != NULL) 1926 return (pathname); 1927 } 1928 pathname = search_library_path(name, ld_library_path, 1929 refobj_path, fdp); 1930 if (pathname != NULL) 1931 return (pathname); 1932 if (objgiven) { 1933 pathname = search_library_path(name, refobj->runpath, 1934 refobj_path, fdp); 1935 if (pathname != NULL) 1936 return (pathname); 1937 } 1938 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1939 if (pathname != NULL) 1940 return (pathname); 1941 pathname = search_library_path(name, gethints(nodeflib), 1942 refobj_path, fdp); 1943 if (pathname != NULL) 1944 return (pathname); 1945 if (objgiven && !nodeflib) { 1946 pathname = search_library_path(name, 1947 ld_standard_library_path, refobj_path, fdp); 1948 if (pathname != NULL) 1949 return (pathname); 1950 } 1951 } 1952 1953 if (objgiven && refobj->path != NULL) { 1954 _rtld_error("Shared object \"%s\" not found, " 1955 "required by \"%s\"", name, basename(refobj->path)); 1956 } else { 1957 _rtld_error("Shared object \"%s\" not found", name); 1958 } 1959 return (NULL); 1960 } 1961 1962 /* 1963 * Given a symbol number in a referencing object, find the corresponding 1964 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1965 * no definition was found. Returns a pointer to the Obj_Entry of the 1966 * defining object via the reference parameter DEFOBJ_OUT. 1967 */ 1968 const Elf_Sym * 1969 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1970 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1971 RtldLockState *lockstate) 1972 { 1973 const Elf_Sym *ref; 1974 const Elf_Sym *def; 1975 const Obj_Entry *defobj; 1976 const Ver_Entry *ve; 1977 SymLook req; 1978 const char *name; 1979 int res; 1980 1981 /* 1982 * If we have already found this symbol, get the information from 1983 * the cache. 1984 */ 1985 if (symnum >= refobj->dynsymcount) 1986 return (NULL); /* Bad object */ 1987 if (cache != NULL && cache[symnum].sym != NULL) { 1988 *defobj_out = cache[symnum].obj; 1989 return (cache[symnum].sym); 1990 } 1991 1992 ref = refobj->symtab + symnum; 1993 name = refobj->strtab + ref->st_name; 1994 def = NULL; 1995 defobj = NULL; 1996 ve = NULL; 1997 1998 /* 1999 * We don't have to do a full scale lookup if the symbol is local. 2000 * We know it will bind to the instance in this load module; to 2001 * which we already have a pointer (ie ref). By not doing a lookup, 2002 * we not only improve performance, but it also avoids unresolvable 2003 * symbols when local symbols are not in the hash table. This has 2004 * been seen with the ia64 toolchain. 2005 */ 2006 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 2007 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 2008 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 2009 symnum); 2010 } 2011 symlook_init(&req, name); 2012 req.flags = flags; 2013 ve = req.ventry = fetch_ventry(refobj, symnum); 2014 req.lockstate = lockstate; 2015 res = symlook_default(&req, refobj); 2016 if (res == 0) { 2017 def = req.sym_out; 2018 defobj = req.defobj_out; 2019 } 2020 } else { 2021 def = ref; 2022 defobj = refobj; 2023 } 2024 2025 /* 2026 * If we found no definition and the reference is weak, treat the 2027 * symbol as having the value zero. 2028 */ 2029 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 2030 def = &sym_zero; 2031 defobj = obj_main; 2032 } 2033 2034 if (def != NULL) { 2035 *defobj_out = defobj; 2036 /* Record the information in the cache to avoid subsequent lookups. */ 2037 if (cache != NULL) { 2038 cache[symnum].sym = def; 2039 cache[symnum].obj = defobj; 2040 } 2041 } else { 2042 if (refobj != &obj_rtld) 2043 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 2044 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 2045 } 2046 return (def); 2047 } 2048 2049 /* 2050 * Return the search path from the ldconfig hints file, reading it if 2051 * necessary. If nostdlib is true, then the default search paths are 2052 * not added to result. 2053 * 2054 * Returns NULL if there are problems with the hints file, 2055 * or if the search path there is empty. 2056 */ 2057 static const char * 2058 gethints(bool nostdlib) 2059 { 2060 static char *filtered_path; 2061 static const char *hints; 2062 static struct elfhints_hdr hdr; 2063 struct fill_search_info_args sargs, hargs; 2064 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 2065 struct dl_serpath *SLPpath, *hintpath; 2066 char *p; 2067 struct stat hint_stat; 2068 unsigned int SLPndx, hintndx, fndx, fcount; 2069 int fd; 2070 size_t flen; 2071 uint32_t dl; 2072 bool skip; 2073 2074 /* First call, read the hints file */ 2075 if (hints == NULL) { 2076 /* Keep from trying again in case the hints file is bad. */ 2077 hints = ""; 2078 2079 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 2080 return (NULL); 2081 2082 /* 2083 * Check of hdr.dirlistlen value against type limit 2084 * intends to pacify static analyzers. Further 2085 * paranoia leads to checks that dirlist is fully 2086 * contained in the file range. 2087 */ 2088 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 2089 hdr.magic != ELFHINTS_MAGIC || 2090 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 2091 fstat(fd, &hint_stat) == -1) { 2092 cleanup1: 2093 close(fd); 2094 hdr.dirlistlen = 0; 2095 return (NULL); 2096 } 2097 dl = hdr.strtab; 2098 if (dl + hdr.dirlist < dl) 2099 goto cleanup1; 2100 dl += hdr.dirlist; 2101 if (dl + hdr.dirlistlen < dl) 2102 goto cleanup1; 2103 dl += hdr.dirlistlen; 2104 if (dl > hint_stat.st_size) 2105 goto cleanup1; 2106 p = xmalloc(hdr.dirlistlen + 1); 2107 if (pread(fd, p, hdr.dirlistlen + 1, 2108 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 2109 p[hdr.dirlistlen] != '\0') { 2110 free(p); 2111 goto cleanup1; 2112 } 2113 hints = p; 2114 close(fd); 2115 } 2116 2117 /* 2118 * If caller agreed to receive list which includes the default 2119 * paths, we are done. Otherwise, if we still did not 2120 * calculated filtered result, do it now. 2121 */ 2122 if (!nostdlib) 2123 return (hints[0] != '\0' ? hints : NULL); 2124 if (filtered_path != NULL) 2125 goto filt_ret; 2126 2127 /* 2128 * Obtain the list of all configured search paths, and the 2129 * list of the default paths. 2130 * 2131 * First estimate the size of the results. 2132 */ 2133 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2134 smeta.dls_cnt = 0; 2135 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 2136 hmeta.dls_cnt = 0; 2137 2138 sargs.request = RTLD_DI_SERINFOSIZE; 2139 sargs.serinfo = &smeta; 2140 hargs.request = RTLD_DI_SERINFOSIZE; 2141 hargs.serinfo = &hmeta; 2142 2143 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2144 &sargs); 2145 path_enumerate(hints, fill_search_info, NULL, &hargs); 2146 2147 SLPinfo = xmalloc(smeta.dls_size); 2148 hintinfo = xmalloc(hmeta.dls_size); 2149 2150 /* 2151 * Next fetch both sets of paths. 2152 */ 2153 sargs.request = RTLD_DI_SERINFO; 2154 sargs.serinfo = SLPinfo; 2155 sargs.serpath = &SLPinfo->dls_serpath[0]; 2156 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2157 2158 hargs.request = RTLD_DI_SERINFO; 2159 hargs.serinfo = hintinfo; 2160 hargs.serpath = &hintinfo->dls_serpath[0]; 2161 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2162 2163 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2164 &sargs); 2165 path_enumerate(hints, fill_search_info, NULL, &hargs); 2166 2167 /* 2168 * Now calculate the difference between two sets, by excluding 2169 * standard paths from the full set. 2170 */ 2171 fndx = 0; 2172 fcount = 0; 2173 filtered_path = xmalloc(hdr.dirlistlen + 1); 2174 hintpath = &hintinfo->dls_serpath[0]; 2175 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2176 skip = false; 2177 SLPpath = &SLPinfo->dls_serpath[0]; 2178 /* 2179 * Check each standard path against current. 2180 */ 2181 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2182 /* matched, skip the path */ 2183 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2184 skip = true; 2185 break; 2186 } 2187 } 2188 if (skip) 2189 continue; 2190 /* 2191 * Not matched against any standard path, add the path 2192 * to result. Separate consequtive paths with ':'. 2193 */ 2194 if (fcount > 0) { 2195 filtered_path[fndx] = ':'; 2196 fndx++; 2197 } 2198 fcount++; 2199 flen = strlen(hintpath->dls_name); 2200 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2201 fndx += flen; 2202 } 2203 filtered_path[fndx] = '\0'; 2204 2205 free(SLPinfo); 2206 free(hintinfo); 2207 2208 filt_ret: 2209 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2210 } 2211 2212 static void 2213 init_dag(Obj_Entry *root) 2214 { 2215 const Needed_Entry *needed; 2216 const Objlist_Entry *elm; 2217 DoneList donelist; 2218 2219 if (root->dag_inited) 2220 return; 2221 donelist_init(&donelist); 2222 2223 /* Root object belongs to own DAG. */ 2224 objlist_push_tail(&root->dldags, root); 2225 objlist_push_tail(&root->dagmembers, root); 2226 donelist_check(&donelist, root); 2227 2228 /* 2229 * Add dependencies of root object to DAG in breadth order 2230 * by exploiting the fact that each new object get added 2231 * to the tail of the dagmembers list. 2232 */ 2233 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2234 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2235 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2236 continue; 2237 objlist_push_tail(&needed->obj->dldags, root); 2238 objlist_push_tail(&root->dagmembers, needed->obj); 2239 } 2240 } 2241 root->dag_inited = true; 2242 } 2243 2244 static void 2245 init_marker(Obj_Entry *marker) 2246 { 2247 2248 bzero(marker, sizeof(*marker)); 2249 marker->marker = true; 2250 } 2251 2252 Obj_Entry * 2253 globallist_curr(const Obj_Entry *obj) 2254 { 2255 2256 for (;;) { 2257 if (obj == NULL) 2258 return (NULL); 2259 if (!obj->marker) 2260 return (__DECONST(Obj_Entry *, obj)); 2261 obj = TAILQ_PREV(obj, obj_entry_q, next); 2262 } 2263 } 2264 2265 Obj_Entry * 2266 globallist_next(const Obj_Entry *obj) 2267 { 2268 2269 for (;;) { 2270 obj = TAILQ_NEXT(obj, next); 2271 if (obj == NULL) 2272 return (NULL); 2273 if (!obj->marker) 2274 return (__DECONST(Obj_Entry *, obj)); 2275 } 2276 } 2277 2278 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2279 static void 2280 hold_object(Obj_Entry *obj) 2281 { 2282 2283 obj->holdcount++; 2284 } 2285 2286 static void 2287 unhold_object(Obj_Entry *obj) 2288 { 2289 2290 assert(obj->holdcount > 0); 2291 if (--obj->holdcount == 0 && obj->unholdfree) 2292 release_object(obj); 2293 } 2294 2295 static void 2296 process_z(Obj_Entry *root) 2297 { 2298 const Objlist_Entry *elm; 2299 Obj_Entry *obj; 2300 2301 /* 2302 * Walk over object DAG and process every dependent object 2303 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2304 * to grow their own DAG. 2305 * 2306 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2307 * symlook_global() to work. 2308 * 2309 * For DF_1_NODELETE, the DAG should have its reference upped. 2310 */ 2311 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2312 obj = elm->obj; 2313 if (obj == NULL) 2314 continue; 2315 if (obj->z_nodelete && !obj->ref_nodel) { 2316 dbg("obj %s -z nodelete", obj->path); 2317 init_dag(obj); 2318 ref_dag(obj); 2319 obj->ref_nodel = true; 2320 } 2321 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2322 dbg("obj %s -z global", obj->path); 2323 objlist_push_tail(&list_global, obj); 2324 init_dag(obj); 2325 } 2326 } 2327 } 2328 2329 static void 2330 parse_rtld_phdr(Obj_Entry *obj) 2331 { 2332 const Elf_Phdr *ph; 2333 Elf_Addr note_start, note_end; 2334 2335 obj->stack_flags = PF_X | PF_R | PF_W; 2336 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2337 obj->phsize; ph++) { 2338 switch (ph->p_type) { 2339 case PT_GNU_STACK: 2340 obj->stack_flags = ph->p_flags; 2341 break; 2342 case PT_GNU_RELRO: 2343 obj->relro_page = obj->relocbase + 2344 trunc_page(ph->p_vaddr); 2345 obj->relro_size = round_page(ph->p_memsz); 2346 break; 2347 case PT_NOTE: 2348 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2349 note_end = note_start + ph->p_filesz; 2350 digest_notes(obj, note_start, note_end); 2351 break; 2352 } 2353 } 2354 } 2355 2356 /* 2357 * Initialize the dynamic linker. The argument is the address at which 2358 * the dynamic linker has been mapped into memory. The primary task of 2359 * this function is to relocate the dynamic linker. 2360 */ 2361 static void 2362 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2363 { 2364 Obj_Entry objtmp; /* Temporary rtld object */ 2365 const Elf_Ehdr *ehdr; 2366 const Elf_Dyn *dyn_rpath; 2367 const Elf_Dyn *dyn_soname; 2368 const Elf_Dyn *dyn_runpath; 2369 2370 #ifdef RTLD_INIT_PAGESIZES_EARLY 2371 /* The page size is required by the dynamic memory allocator. */ 2372 init_pagesizes(aux_info); 2373 #endif 2374 2375 /* 2376 * Conjure up an Obj_Entry structure for the dynamic linker. 2377 * 2378 * The "path" member can't be initialized yet because string constants 2379 * cannot yet be accessed. Below we will set it correctly. 2380 */ 2381 memset(&objtmp, 0, sizeof(objtmp)); 2382 objtmp.path = NULL; 2383 objtmp.rtld = true; 2384 objtmp.mapbase = mapbase; 2385 #ifdef PIC 2386 objtmp.relocbase = mapbase; 2387 #endif 2388 2389 objtmp.dynamic = rtld_dynamic(&objtmp); 2390 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2391 assert(objtmp.needed == NULL); 2392 #if !defined(__mips__) 2393 /* MIPS has a bogus DT_TEXTREL. */ 2394 assert(!objtmp.textrel); 2395 #endif 2396 /* 2397 * Temporarily put the dynamic linker entry into the object list, so 2398 * that symbols can be found. 2399 */ 2400 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2401 2402 ehdr = (Elf_Ehdr *)mapbase; 2403 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2404 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2405 2406 /* Initialize the object list. */ 2407 TAILQ_INIT(&obj_list); 2408 2409 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2410 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2411 2412 #ifndef RTLD_INIT_PAGESIZES_EARLY 2413 /* The page size is required by the dynamic memory allocator. */ 2414 init_pagesizes(aux_info); 2415 #endif 2416 2417 if (aux_info[AT_OSRELDATE] != NULL) 2418 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2419 2420 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2421 2422 /* Replace the path with a dynamically allocated copy. */ 2423 obj_rtld.path = xstrdup(ld_path_rtld); 2424 2425 parse_rtld_phdr(&obj_rtld); 2426 if (obj_enforce_relro(&obj_rtld) == -1) 2427 rtld_die(); 2428 2429 r_debug.r_version = R_DEBUG_VERSION; 2430 r_debug.r_brk = r_debug_state; 2431 r_debug.r_state = RT_CONSISTENT; 2432 r_debug.r_ldbase = obj_rtld.relocbase; 2433 } 2434 2435 /* 2436 * Retrieve the array of supported page sizes. The kernel provides the page 2437 * sizes in increasing order. 2438 */ 2439 static void 2440 init_pagesizes(Elf_Auxinfo **aux_info) 2441 { 2442 static size_t psa[MAXPAGESIZES]; 2443 int mib[2]; 2444 size_t len, size; 2445 2446 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2447 NULL) { 2448 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2449 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2450 } else { 2451 len = 2; 2452 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2453 size = sizeof(psa); 2454 else { 2455 /* As a fallback, retrieve the base page size. */ 2456 size = sizeof(psa[0]); 2457 if (aux_info[AT_PAGESZ] != NULL) { 2458 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2459 goto psa_filled; 2460 } else { 2461 mib[0] = CTL_HW; 2462 mib[1] = HW_PAGESIZE; 2463 len = 2; 2464 } 2465 } 2466 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2467 _rtld_error("sysctl for hw.pagesize(s) failed"); 2468 rtld_die(); 2469 } 2470 psa_filled: 2471 pagesizes = psa; 2472 } 2473 npagesizes = size / sizeof(pagesizes[0]); 2474 /* Discard any invalid entries at the end of the array. */ 2475 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2476 npagesizes--; 2477 } 2478 2479 /* 2480 * Add the init functions from a needed object list (and its recursive 2481 * needed objects) to "list". This is not used directly; it is a helper 2482 * function for initlist_add_objects(). The write lock must be held 2483 * when this function is called. 2484 */ 2485 static void 2486 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2487 { 2488 /* Recursively process the successor needed objects. */ 2489 if (needed->next != NULL) 2490 initlist_add_neededs(needed->next, list); 2491 2492 /* Process the current needed object. */ 2493 if (needed->obj != NULL) 2494 initlist_add_objects(needed->obj, needed->obj, list); 2495 } 2496 2497 /* 2498 * Scan all of the DAGs rooted in the range of objects from "obj" to 2499 * "tail" and add their init functions to "list". This recurses over 2500 * the DAGs and ensure the proper init ordering such that each object's 2501 * needed libraries are initialized before the object itself. At the 2502 * same time, this function adds the objects to the global finalization 2503 * list "list_fini" in the opposite order. The write lock must be 2504 * held when this function is called. 2505 */ 2506 static void 2507 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2508 { 2509 Obj_Entry *nobj; 2510 2511 if (obj->init_scanned || obj->init_done) 2512 return; 2513 obj->init_scanned = true; 2514 2515 /* Recursively process the successor objects. */ 2516 nobj = globallist_next(obj); 2517 if (nobj != NULL && obj != tail) 2518 initlist_add_objects(nobj, tail, list); 2519 2520 /* Recursively process the needed objects. */ 2521 if (obj->needed != NULL) 2522 initlist_add_neededs(obj->needed, list); 2523 if (obj->needed_filtees != NULL) 2524 initlist_add_neededs(obj->needed_filtees, list); 2525 if (obj->needed_aux_filtees != NULL) 2526 initlist_add_neededs(obj->needed_aux_filtees, list); 2527 2528 /* Add the object to the init list. */ 2529 objlist_push_tail(list, obj); 2530 2531 /* Add the object to the global fini list in the reverse order. */ 2532 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2533 && !obj->on_fini_list) { 2534 objlist_push_head(&list_fini, obj); 2535 obj->on_fini_list = true; 2536 } 2537 } 2538 2539 #ifndef FPTR_TARGET 2540 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2541 #endif 2542 2543 static void 2544 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2545 { 2546 Needed_Entry *needed, *needed1; 2547 2548 for (needed = n; needed != NULL; needed = needed->next) { 2549 if (needed->obj != NULL) { 2550 dlclose_locked(needed->obj, lockstate); 2551 needed->obj = NULL; 2552 } 2553 } 2554 for (needed = n; needed != NULL; needed = needed1) { 2555 needed1 = needed->next; 2556 free(needed); 2557 } 2558 } 2559 2560 static void 2561 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2562 { 2563 2564 free_needed_filtees(obj->needed_filtees, lockstate); 2565 obj->needed_filtees = NULL; 2566 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2567 obj->needed_aux_filtees = NULL; 2568 obj->filtees_loaded = false; 2569 } 2570 2571 static void 2572 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2573 RtldLockState *lockstate) 2574 { 2575 2576 for (; needed != NULL; needed = needed->next) { 2577 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2578 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2579 RTLD_LOCAL, lockstate); 2580 } 2581 } 2582 2583 static void 2584 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2585 { 2586 2587 lock_restart_for_upgrade(lockstate); 2588 if (!obj->filtees_loaded) { 2589 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2590 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2591 obj->filtees_loaded = true; 2592 } 2593 } 2594 2595 static int 2596 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2597 { 2598 Obj_Entry *obj1; 2599 2600 for (; needed != NULL; needed = needed->next) { 2601 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2602 flags & ~RTLD_LO_NOLOAD); 2603 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2604 return (-1); 2605 } 2606 return (0); 2607 } 2608 2609 /* 2610 * Given a shared object, traverse its list of needed objects, and load 2611 * each of them. Returns 0 on success. Generates an error message and 2612 * returns -1 on failure. 2613 */ 2614 static int 2615 load_needed_objects(Obj_Entry *first, int flags) 2616 { 2617 Obj_Entry *obj; 2618 2619 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2620 if (obj->marker) 2621 continue; 2622 if (process_needed(obj, obj->needed, flags) == -1) 2623 return (-1); 2624 } 2625 return (0); 2626 } 2627 2628 static int 2629 load_preload_objects(const char *penv, bool isfd) 2630 { 2631 Obj_Entry *obj; 2632 const char *name; 2633 size_t len; 2634 char savech, *p, *psave; 2635 int fd; 2636 static const char delim[] = " \t:;"; 2637 2638 if (penv == NULL) 2639 return (0); 2640 2641 p = psave = xstrdup(penv); 2642 p += strspn(p, delim); 2643 while (*p != '\0') { 2644 len = strcspn(p, delim); 2645 2646 savech = p[len]; 2647 p[len] = '\0'; 2648 if (isfd) { 2649 name = NULL; 2650 fd = parse_integer(p); 2651 if (fd == -1) { 2652 free(psave); 2653 return (-1); 2654 } 2655 } else { 2656 name = p; 2657 fd = -1; 2658 } 2659 2660 obj = load_object(name, fd, NULL, 0); 2661 if (obj == NULL) { 2662 free(psave); 2663 return (-1); /* XXX - cleanup */ 2664 } 2665 obj->z_interpose = true; 2666 p[len] = savech; 2667 p += len; 2668 p += strspn(p, delim); 2669 } 2670 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2671 2672 free(psave); 2673 return (0); 2674 } 2675 2676 static const char * 2677 printable_path(const char *path) 2678 { 2679 2680 return (path == NULL ? "<unknown>" : path); 2681 } 2682 2683 /* 2684 * Load a shared object into memory, if it is not already loaded. The 2685 * object may be specified by name or by user-supplied file descriptor 2686 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2687 * duplicate is. 2688 * 2689 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2690 * on failure. 2691 */ 2692 static Obj_Entry * 2693 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2694 { 2695 Obj_Entry *obj; 2696 int fd; 2697 struct stat sb; 2698 char *path; 2699 2700 fd = -1; 2701 if (name != NULL) { 2702 TAILQ_FOREACH(obj, &obj_list, next) { 2703 if (obj->marker || obj->doomed) 2704 continue; 2705 if (object_match_name(obj, name)) 2706 return (obj); 2707 } 2708 2709 path = find_library(name, refobj, &fd); 2710 if (path == NULL) 2711 return (NULL); 2712 } else 2713 path = NULL; 2714 2715 if (fd >= 0) { 2716 /* 2717 * search_library_pathfds() opens a fresh file descriptor for the 2718 * library, so there is no need to dup(). 2719 */ 2720 } else if (fd_u == -1) { 2721 /* 2722 * If we didn't find a match by pathname, or the name is not 2723 * supplied, open the file and check again by device and inode. 2724 * This avoids false mismatches caused by multiple links or ".." 2725 * in pathnames. 2726 * 2727 * To avoid a race, we open the file and use fstat() rather than 2728 * using stat(). 2729 */ 2730 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2731 _rtld_error("Cannot open \"%s\"", path); 2732 free(path); 2733 return (NULL); 2734 } 2735 } else { 2736 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2737 if (fd == -1) { 2738 _rtld_error("Cannot dup fd"); 2739 free(path); 2740 return (NULL); 2741 } 2742 } 2743 if (fstat(fd, &sb) == -1) { 2744 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2745 close(fd); 2746 free(path); 2747 return (NULL); 2748 } 2749 TAILQ_FOREACH(obj, &obj_list, next) { 2750 if (obj->marker || obj->doomed) 2751 continue; 2752 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2753 break; 2754 } 2755 if (obj != NULL && name != NULL) { 2756 object_add_name(obj, name); 2757 free(path); 2758 close(fd); 2759 return (obj); 2760 } 2761 if (flags & RTLD_LO_NOLOAD) { 2762 free(path); 2763 close(fd); 2764 return (NULL); 2765 } 2766 2767 /* First use of this object, so we must map it in */ 2768 obj = do_load_object(fd, name, path, &sb, flags); 2769 if (obj == NULL) 2770 free(path); 2771 close(fd); 2772 2773 return (obj); 2774 } 2775 2776 static Obj_Entry * 2777 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2778 int flags) 2779 { 2780 Obj_Entry *obj; 2781 struct statfs fs; 2782 2783 /* 2784 * First, make sure that environment variables haven't been 2785 * used to circumvent the noexec flag on a filesystem. 2786 * We ignore fstatfs(2) failures, since fd might reference 2787 * not a file, e.g. shmfd. 2788 */ 2789 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && 2790 (fs.f_flags & MNT_NOEXEC) != 0) { 2791 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2792 return (NULL); 2793 } 2794 2795 dbg("loading \"%s\"", printable_path(path)); 2796 obj = map_object(fd, printable_path(path), sbp); 2797 if (obj == NULL) 2798 return (NULL); 2799 2800 /* 2801 * If DT_SONAME is present in the object, digest_dynamic2 already 2802 * added it to the object names. 2803 */ 2804 if (name != NULL) 2805 object_add_name(obj, name); 2806 obj->path = path; 2807 if (!digest_dynamic(obj, 0)) 2808 goto errp; 2809 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2810 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2811 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2812 dbg("refusing to load PIE executable \"%s\"", obj->path); 2813 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2814 goto errp; 2815 } 2816 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2817 RTLD_LO_DLOPEN) { 2818 dbg("refusing to load non-loadable \"%s\"", obj->path); 2819 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2820 goto errp; 2821 } 2822 2823 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2824 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2825 obj_count++; 2826 obj_loads++; 2827 linkmap_add(obj); /* for GDB & dlinfo() */ 2828 max_stack_flags |= obj->stack_flags; 2829 2830 dbg(" %p .. %p: %s", obj->mapbase, 2831 obj->mapbase + obj->mapsize - 1, obj->path); 2832 if (obj->textrel) 2833 dbg(" WARNING: %s has impure text", obj->path); 2834 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2835 obj->path); 2836 2837 return (obj); 2838 2839 errp: 2840 munmap(obj->mapbase, obj->mapsize); 2841 obj_free(obj); 2842 return (NULL); 2843 } 2844 2845 Obj_Entry * 2846 obj_from_addr(const void *addr) 2847 { 2848 Obj_Entry *obj; 2849 2850 TAILQ_FOREACH(obj, &obj_list, next) { 2851 if (obj->marker) 2852 continue; 2853 if (addr < (void *) obj->mapbase) 2854 continue; 2855 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2856 return obj; 2857 } 2858 return (NULL); 2859 } 2860 2861 static void 2862 preinit_main(void) 2863 { 2864 Elf_Addr *preinit_addr; 2865 int index; 2866 2867 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2868 if (preinit_addr == NULL) 2869 return; 2870 2871 for (index = 0; index < obj_main->preinit_array_num; index++) { 2872 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2873 dbg("calling preinit function for %s at %p", obj_main->path, 2874 (void *)preinit_addr[index]); 2875 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2876 0, 0, obj_main->path); 2877 call_init_pointer(obj_main, preinit_addr[index]); 2878 } 2879 } 2880 } 2881 2882 /* 2883 * Call the finalization functions for each of the objects in "list" 2884 * belonging to the DAG of "root" and referenced once. If NULL "root" 2885 * is specified, every finalization function will be called regardless 2886 * of the reference count and the list elements won't be freed. All of 2887 * the objects are expected to have non-NULL fini functions. 2888 */ 2889 static void 2890 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2891 { 2892 Objlist_Entry *elm; 2893 struct dlerror_save *saved_msg; 2894 Elf_Addr *fini_addr; 2895 int index; 2896 2897 assert(root == NULL || root->refcount == 1); 2898 2899 if (root != NULL) 2900 root->doomed = true; 2901 2902 /* 2903 * Preserve the current error message since a fini function might 2904 * call into the dynamic linker and overwrite it. 2905 */ 2906 saved_msg = errmsg_save(); 2907 do { 2908 STAILQ_FOREACH(elm, list, link) { 2909 if (root != NULL && (elm->obj->refcount != 1 || 2910 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2911 continue; 2912 /* Remove object from fini list to prevent recursive invocation. */ 2913 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2914 /* Ensure that new references cannot be acquired. */ 2915 elm->obj->doomed = true; 2916 2917 hold_object(elm->obj); 2918 lock_release(rtld_bind_lock, lockstate); 2919 /* 2920 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2921 * When this happens, DT_FINI_ARRAY is processed first. 2922 */ 2923 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2924 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2925 for (index = elm->obj->fini_array_num - 1; index >= 0; 2926 index--) { 2927 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2928 dbg("calling fini function for %s at %p", 2929 elm->obj->path, (void *)fini_addr[index]); 2930 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2931 (void *)fini_addr[index], 0, 0, elm->obj->path); 2932 call_initfini_pointer(elm->obj, fini_addr[index]); 2933 } 2934 } 2935 } 2936 if (elm->obj->fini != (Elf_Addr)NULL) { 2937 dbg("calling fini function for %s at %p", elm->obj->path, 2938 (void *)elm->obj->fini); 2939 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2940 0, 0, elm->obj->path); 2941 call_initfini_pointer(elm->obj, elm->obj->fini); 2942 } 2943 wlock_acquire(rtld_bind_lock, lockstate); 2944 unhold_object(elm->obj); 2945 /* No need to free anything if process is going down. */ 2946 if (root != NULL) 2947 free(elm); 2948 /* 2949 * We must restart the list traversal after every fini call 2950 * because a dlclose() call from the fini function or from 2951 * another thread might have modified the reference counts. 2952 */ 2953 break; 2954 } 2955 } while (elm != NULL); 2956 errmsg_restore(saved_msg); 2957 } 2958 2959 /* 2960 * Call the initialization functions for each of the objects in 2961 * "list". All of the objects are expected to have non-NULL init 2962 * functions. 2963 */ 2964 static void 2965 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2966 { 2967 Objlist_Entry *elm; 2968 Obj_Entry *obj; 2969 struct dlerror_save *saved_msg; 2970 Elf_Addr *init_addr; 2971 void (*reg)(void (*)(void)); 2972 int index; 2973 2974 /* 2975 * Clean init_scanned flag so that objects can be rechecked and 2976 * possibly initialized earlier if any of vectors called below 2977 * cause the change by using dlopen. 2978 */ 2979 TAILQ_FOREACH(obj, &obj_list, next) { 2980 if (obj->marker) 2981 continue; 2982 obj->init_scanned = false; 2983 } 2984 2985 /* 2986 * Preserve the current error message since an init function might 2987 * call into the dynamic linker and overwrite it. 2988 */ 2989 saved_msg = errmsg_save(); 2990 STAILQ_FOREACH(elm, list, link) { 2991 if (elm->obj->init_done) /* Initialized early. */ 2992 continue; 2993 /* 2994 * Race: other thread might try to use this object before current 2995 * one completes the initialization. Not much can be done here 2996 * without better locking. 2997 */ 2998 elm->obj->init_done = true; 2999 hold_object(elm->obj); 3000 reg = NULL; 3001 if (elm->obj == obj_main && obj_main->crt_no_init) { 3002 reg = (void (*)(void (*)(void)))get_program_var_addr( 3003 "__libc_atexit", lockstate); 3004 } 3005 lock_release(rtld_bind_lock, lockstate); 3006 if (reg != NULL) { 3007 reg(rtld_exit); 3008 rtld_exit_ptr = rtld_nop_exit; 3009 } 3010 3011 /* 3012 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 3013 * When this happens, DT_INIT is processed first. 3014 */ 3015 if (elm->obj->init != (Elf_Addr)NULL) { 3016 dbg("calling init function for %s at %p", elm->obj->path, 3017 (void *)elm->obj->init); 3018 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 3019 0, 0, elm->obj->path); 3020 call_init_pointer(elm->obj, elm->obj->init); 3021 } 3022 init_addr = (Elf_Addr *)elm->obj->init_array; 3023 if (init_addr != NULL) { 3024 for (index = 0; index < elm->obj->init_array_num; index++) { 3025 if (init_addr[index] != 0 && init_addr[index] != 1) { 3026 dbg("calling init function for %s at %p", elm->obj->path, 3027 (void *)init_addr[index]); 3028 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 3029 (void *)init_addr[index], 0, 0, elm->obj->path); 3030 call_init_pointer(elm->obj, init_addr[index]); 3031 } 3032 } 3033 } 3034 wlock_acquire(rtld_bind_lock, lockstate); 3035 unhold_object(elm->obj); 3036 } 3037 errmsg_restore(saved_msg); 3038 } 3039 3040 static void 3041 objlist_clear(Objlist *list) 3042 { 3043 Objlist_Entry *elm; 3044 3045 while (!STAILQ_EMPTY(list)) { 3046 elm = STAILQ_FIRST(list); 3047 STAILQ_REMOVE_HEAD(list, link); 3048 free(elm); 3049 } 3050 } 3051 3052 static Objlist_Entry * 3053 objlist_find(Objlist *list, const Obj_Entry *obj) 3054 { 3055 Objlist_Entry *elm; 3056 3057 STAILQ_FOREACH(elm, list, link) 3058 if (elm->obj == obj) 3059 return elm; 3060 return (NULL); 3061 } 3062 3063 static void 3064 objlist_init(Objlist *list) 3065 { 3066 STAILQ_INIT(list); 3067 } 3068 3069 static void 3070 objlist_push_head(Objlist *list, Obj_Entry *obj) 3071 { 3072 Objlist_Entry *elm; 3073 3074 elm = NEW(Objlist_Entry); 3075 elm->obj = obj; 3076 STAILQ_INSERT_HEAD(list, elm, link); 3077 } 3078 3079 static void 3080 objlist_push_tail(Objlist *list, Obj_Entry *obj) 3081 { 3082 Objlist_Entry *elm; 3083 3084 elm = NEW(Objlist_Entry); 3085 elm->obj = obj; 3086 STAILQ_INSERT_TAIL(list, elm, link); 3087 } 3088 3089 static void 3090 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 3091 { 3092 Objlist_Entry *elm, *listelm; 3093 3094 STAILQ_FOREACH(listelm, list, link) { 3095 if (listelm->obj == listobj) 3096 break; 3097 } 3098 elm = NEW(Objlist_Entry); 3099 elm->obj = obj; 3100 if (listelm != NULL) 3101 STAILQ_INSERT_AFTER(list, listelm, elm, link); 3102 else 3103 STAILQ_INSERT_TAIL(list, elm, link); 3104 } 3105 3106 static void 3107 objlist_remove(Objlist *list, Obj_Entry *obj) 3108 { 3109 Objlist_Entry *elm; 3110 3111 if ((elm = objlist_find(list, obj)) != NULL) { 3112 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 3113 free(elm); 3114 } 3115 } 3116 3117 /* 3118 * Relocate dag rooted in the specified object. 3119 * Returns 0 on success, or -1 on failure. 3120 */ 3121 3122 static int 3123 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 3124 int flags, RtldLockState *lockstate) 3125 { 3126 Objlist_Entry *elm; 3127 int error; 3128 3129 error = 0; 3130 STAILQ_FOREACH(elm, &root->dagmembers, link) { 3131 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 3132 lockstate); 3133 if (error == -1) 3134 break; 3135 } 3136 return (error); 3137 } 3138 3139 /* 3140 * Prepare for, or clean after, relocating an object marked with 3141 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 3142 * segments are remapped read-write. After relocations are done, the 3143 * segment's permissions are returned back to the modes specified in 3144 * the phdrs. If any relocation happened, or always for wired 3145 * program, COW is triggered. 3146 */ 3147 static int 3148 reloc_textrel_prot(Obj_Entry *obj, bool before) 3149 { 3150 const Elf_Phdr *ph; 3151 void *base; 3152 size_t l, sz; 3153 int prot; 3154 3155 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 3156 l--, ph++) { 3157 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 3158 continue; 3159 base = obj->relocbase + trunc_page(ph->p_vaddr); 3160 sz = round_page(ph->p_vaddr + ph->p_filesz) - 3161 trunc_page(ph->p_vaddr); 3162 prot = before ? (PROT_READ | PROT_WRITE) : 3163 convert_prot(ph->p_flags); 3164 if (mprotect(base, sz, prot) == -1) { 3165 _rtld_error("%s: Cannot write-%sable text segment: %s", 3166 obj->path, before ? "en" : "dis", 3167 rtld_strerror(errno)); 3168 return (-1); 3169 } 3170 } 3171 return (0); 3172 } 3173 3174 /* Process RELR relative relocations. */ 3175 static void 3176 reloc_relr(Obj_Entry *obj) 3177 { 3178 const Elf_Relr *relr, *relrlim; 3179 Elf_Addr *where; 3180 3181 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); 3182 for (relr = obj->relr; relr < relrlim; relr++) { 3183 Elf_Relr entry = *relr; 3184 3185 if ((entry & 1) == 0) { 3186 where = (Elf_Addr *)(obj->relocbase + entry); 3187 *where++ += (Elf_Addr)obj->relocbase; 3188 } else { 3189 for (long i = 0; (entry >>= 1) != 0; i++) 3190 if ((entry & 1) != 0) 3191 where[i] += (Elf_Addr)obj->relocbase; 3192 where += CHAR_BIT * sizeof(Elf_Relr) - 1; 3193 } 3194 } 3195 } 3196 3197 /* 3198 * Relocate single object. 3199 * Returns 0 on success, or -1 on failure. 3200 */ 3201 static int 3202 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3203 int flags, RtldLockState *lockstate) 3204 { 3205 3206 if (obj->relocated) 3207 return (0); 3208 obj->relocated = true; 3209 if (obj != rtldobj) 3210 dbg("relocating \"%s\"", obj->path); 3211 3212 if (obj->symtab == NULL || obj->strtab == NULL || 3213 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) 3214 dbg("object %s has no run-time symbol table", obj->path); 3215 3216 /* There are relocations to the write-protected text segment. */ 3217 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3218 return (-1); 3219 3220 /* Process the non-PLT non-IFUNC relocations. */ 3221 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3222 return (-1); 3223 reloc_relr(obj); 3224 3225 /* Re-protected the text segment. */ 3226 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3227 return (-1); 3228 3229 /* Set the special PLT or GOT entries. */ 3230 init_pltgot(obj); 3231 3232 /* Process the PLT relocations. */ 3233 if (reloc_plt(obj, flags, lockstate) == -1) 3234 return (-1); 3235 /* Relocate the jump slots if we are doing immediate binding. */ 3236 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3237 lockstate) == -1) 3238 return (-1); 3239 3240 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3241 return (-1); 3242 3243 /* 3244 * Set up the magic number and version in the Obj_Entry. These 3245 * were checked in the crt1.o from the original ElfKit, so we 3246 * set them for backward compatibility. 3247 */ 3248 obj->magic = RTLD_MAGIC; 3249 obj->version = RTLD_VERSION; 3250 3251 return (0); 3252 } 3253 3254 /* 3255 * Relocate newly-loaded shared objects. The argument is a pointer to 3256 * the Obj_Entry for the first such object. All objects from the first 3257 * to the end of the list of objects are relocated. Returns 0 on success, 3258 * or -1 on failure. 3259 */ 3260 static int 3261 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3262 int flags, RtldLockState *lockstate) 3263 { 3264 Obj_Entry *obj; 3265 int error; 3266 3267 for (error = 0, obj = first; obj != NULL; 3268 obj = TAILQ_NEXT(obj, next)) { 3269 if (obj->marker) 3270 continue; 3271 error = relocate_object(obj, bind_now, rtldobj, flags, 3272 lockstate); 3273 if (error == -1) 3274 break; 3275 } 3276 return (error); 3277 } 3278 3279 /* 3280 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3281 * referencing STT_GNU_IFUNC symbols is postponed till the other 3282 * relocations are done. The indirect functions specified as 3283 * ifunc are allowed to call other symbols, so we need to have 3284 * objects relocated before asking for resolution from indirects. 3285 * 3286 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3287 * instead of the usual lazy handling of PLT slots. It is 3288 * consistent with how GNU does it. 3289 */ 3290 static int 3291 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3292 RtldLockState *lockstate) 3293 { 3294 3295 if (obj->ifuncs_resolved) 3296 return (0); 3297 obj->ifuncs_resolved = true; 3298 if (!obj->irelative && !obj->irelative_nonplt && 3299 !((obj->bind_now || bind_now) && obj->gnu_ifunc) && 3300 !obj->non_plt_gnu_ifunc) 3301 return (0); 3302 if (obj_disable_relro(obj) == -1 || 3303 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3304 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3305 lockstate) == -1) || 3306 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3307 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3308 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, 3309 flags | SYMLOOK_IFUNC, lockstate) == -1) || 3310 obj_enforce_relro(obj) == -1) 3311 return (-1); 3312 return (0); 3313 } 3314 3315 static int 3316 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3317 RtldLockState *lockstate) 3318 { 3319 Objlist_Entry *elm; 3320 Obj_Entry *obj; 3321 3322 STAILQ_FOREACH(elm, list, link) { 3323 obj = elm->obj; 3324 if (obj->marker) 3325 continue; 3326 if (resolve_object_ifunc(obj, bind_now, flags, 3327 lockstate) == -1) 3328 return (-1); 3329 } 3330 return (0); 3331 } 3332 3333 /* 3334 * Cleanup procedure. It will be called (by the atexit mechanism) just 3335 * before the process exits. 3336 */ 3337 static void 3338 rtld_exit(void) 3339 { 3340 RtldLockState lockstate; 3341 3342 wlock_acquire(rtld_bind_lock, &lockstate); 3343 dbg("rtld_exit()"); 3344 objlist_call_fini(&list_fini, NULL, &lockstate); 3345 /* No need to remove the items from the list, since we are exiting. */ 3346 if (!libmap_disable) 3347 lm_fini(); 3348 lock_release(rtld_bind_lock, &lockstate); 3349 } 3350 3351 static void 3352 rtld_nop_exit(void) 3353 { 3354 } 3355 3356 /* 3357 * Iterate over a search path, translate each element, and invoke the 3358 * callback on the result. 3359 */ 3360 static void * 3361 path_enumerate(const char *path, path_enum_proc callback, 3362 const char *refobj_path, void *arg) 3363 { 3364 const char *trans; 3365 if (path == NULL) 3366 return (NULL); 3367 3368 path += strspn(path, ":;"); 3369 while (*path != '\0') { 3370 size_t len; 3371 char *res; 3372 3373 len = strcspn(path, ":;"); 3374 trans = lm_findn(refobj_path, path, len); 3375 if (trans) 3376 res = callback(trans, strlen(trans), arg); 3377 else 3378 res = callback(path, len, arg); 3379 3380 if (res != NULL) 3381 return (res); 3382 3383 path += len; 3384 path += strspn(path, ":;"); 3385 } 3386 3387 return (NULL); 3388 } 3389 3390 struct try_library_args { 3391 const char *name; 3392 size_t namelen; 3393 char *buffer; 3394 size_t buflen; 3395 int fd; 3396 }; 3397 3398 static void * 3399 try_library_path(const char *dir, size_t dirlen, void *param) 3400 { 3401 struct try_library_args *arg; 3402 int fd; 3403 3404 arg = param; 3405 if (*dir == '/' || trust) { 3406 char *pathname; 3407 3408 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3409 return (NULL); 3410 3411 pathname = arg->buffer; 3412 strncpy(pathname, dir, dirlen); 3413 pathname[dirlen] = '/'; 3414 strcpy(pathname + dirlen + 1, arg->name); 3415 3416 dbg(" Trying \"%s\"", pathname); 3417 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3418 if (fd >= 0) { 3419 dbg(" Opened \"%s\", fd %d", pathname, fd); 3420 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3421 strcpy(pathname, arg->buffer); 3422 arg->fd = fd; 3423 return (pathname); 3424 } else { 3425 dbg(" Failed to open \"%s\": %s", 3426 pathname, rtld_strerror(errno)); 3427 } 3428 } 3429 return (NULL); 3430 } 3431 3432 static char * 3433 search_library_path(const char *name, const char *path, 3434 const char *refobj_path, int *fdp) 3435 { 3436 char *p; 3437 struct try_library_args arg; 3438 3439 if (path == NULL) 3440 return (NULL); 3441 3442 arg.name = name; 3443 arg.namelen = strlen(name); 3444 arg.buffer = xmalloc(PATH_MAX); 3445 arg.buflen = PATH_MAX; 3446 arg.fd = -1; 3447 3448 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3449 *fdp = arg.fd; 3450 3451 free(arg.buffer); 3452 3453 return (p); 3454 } 3455 3456 3457 /* 3458 * Finds the library with the given name using the directory descriptors 3459 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3460 * 3461 * Returns a freshly-opened close-on-exec file descriptor for the library, 3462 * or -1 if the library cannot be found. 3463 */ 3464 static char * 3465 search_library_pathfds(const char *name, const char *path, int *fdp) 3466 { 3467 char *envcopy, *fdstr, *found, *last_token; 3468 size_t len; 3469 int dirfd, fd; 3470 3471 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3472 3473 /* Don't load from user-specified libdirs into setuid binaries. */ 3474 if (!trust) 3475 return (NULL); 3476 3477 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3478 if (path == NULL) 3479 return (NULL); 3480 3481 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3482 if (name[0] == '/') { 3483 dbg("Absolute path (%s) passed to %s", name, __func__); 3484 return (NULL); 3485 } 3486 3487 /* 3488 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3489 * copy of the path, as strtok_r rewrites separator tokens 3490 * with '\0'. 3491 */ 3492 found = NULL; 3493 envcopy = xstrdup(path); 3494 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3495 fdstr = strtok_r(NULL, ":", &last_token)) { 3496 dirfd = parse_integer(fdstr); 3497 if (dirfd < 0) { 3498 _rtld_error("failed to parse directory FD: '%s'", 3499 fdstr); 3500 break; 3501 } 3502 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3503 if (fd >= 0) { 3504 *fdp = fd; 3505 len = strlen(fdstr) + strlen(name) + 3; 3506 found = xmalloc(len); 3507 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3508 _rtld_error("error generating '%d/%s'", 3509 dirfd, name); 3510 rtld_die(); 3511 } 3512 dbg("open('%s') => %d", found, fd); 3513 break; 3514 } 3515 } 3516 free(envcopy); 3517 3518 return (found); 3519 } 3520 3521 3522 int 3523 dlclose(void *handle) 3524 { 3525 RtldLockState lockstate; 3526 int error; 3527 3528 wlock_acquire(rtld_bind_lock, &lockstate); 3529 error = dlclose_locked(handle, &lockstate); 3530 lock_release(rtld_bind_lock, &lockstate); 3531 return (error); 3532 } 3533 3534 static int 3535 dlclose_locked(void *handle, RtldLockState *lockstate) 3536 { 3537 Obj_Entry *root; 3538 3539 root = dlcheck(handle); 3540 if (root == NULL) 3541 return (-1); 3542 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3543 root->path); 3544 3545 /* Unreference the object and its dependencies. */ 3546 root->dl_refcount--; 3547 3548 if (root->refcount == 1) { 3549 /* 3550 * The object will be no longer referenced, so we must unload it. 3551 * First, call the fini functions. 3552 */ 3553 objlist_call_fini(&list_fini, root, lockstate); 3554 3555 unref_dag(root); 3556 3557 /* Finish cleaning up the newly-unreferenced objects. */ 3558 GDB_STATE(RT_DELETE,&root->linkmap); 3559 unload_object(root, lockstate); 3560 GDB_STATE(RT_CONSISTENT,NULL); 3561 } else 3562 unref_dag(root); 3563 3564 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3565 return (0); 3566 } 3567 3568 char * 3569 dlerror(void) 3570 { 3571 if (*(lockinfo.dlerror_seen()) != 0) 3572 return (NULL); 3573 *lockinfo.dlerror_seen() = 1; 3574 return (lockinfo.dlerror_loc()); 3575 } 3576 3577 /* 3578 * This function is deprecated and has no effect. 3579 */ 3580 void 3581 dllockinit(void *context, 3582 void *(*_lock_create)(void *context) __unused, 3583 void (*_rlock_acquire)(void *lock) __unused, 3584 void (*_wlock_acquire)(void *lock) __unused, 3585 void (*_lock_release)(void *lock) __unused, 3586 void (*_lock_destroy)(void *lock) __unused, 3587 void (*context_destroy)(void *context)) 3588 { 3589 static void *cur_context; 3590 static void (*cur_context_destroy)(void *); 3591 3592 /* Just destroy the context from the previous call, if necessary. */ 3593 if (cur_context_destroy != NULL) 3594 cur_context_destroy(cur_context); 3595 cur_context = context; 3596 cur_context_destroy = context_destroy; 3597 } 3598 3599 void * 3600 dlopen(const char *name, int mode) 3601 { 3602 3603 return (rtld_dlopen(name, -1, mode)); 3604 } 3605 3606 void * 3607 fdlopen(int fd, int mode) 3608 { 3609 3610 return (rtld_dlopen(NULL, fd, mode)); 3611 } 3612 3613 static void * 3614 rtld_dlopen(const char *name, int fd, int mode) 3615 { 3616 RtldLockState lockstate; 3617 int lo_flags; 3618 3619 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3620 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3621 if (ld_tracing != NULL) { 3622 rlock_acquire(rtld_bind_lock, &lockstate); 3623 if (sigsetjmp(lockstate.env, 0) != 0) 3624 lock_upgrade(rtld_bind_lock, &lockstate); 3625 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3626 lock_release(rtld_bind_lock, &lockstate); 3627 } 3628 lo_flags = RTLD_LO_DLOPEN; 3629 if (mode & RTLD_NODELETE) 3630 lo_flags |= RTLD_LO_NODELETE; 3631 if (mode & RTLD_NOLOAD) 3632 lo_flags |= RTLD_LO_NOLOAD; 3633 if (mode & RTLD_DEEPBIND) 3634 lo_flags |= RTLD_LO_DEEPBIND; 3635 if (ld_tracing != NULL) 3636 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3637 3638 return (dlopen_object(name, fd, obj_main, lo_flags, 3639 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3640 } 3641 3642 static void 3643 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3644 { 3645 3646 obj->dl_refcount--; 3647 unref_dag(obj); 3648 if (obj->refcount == 0) 3649 unload_object(obj, lockstate); 3650 } 3651 3652 static Obj_Entry * 3653 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3654 int mode, RtldLockState *lockstate) 3655 { 3656 Obj_Entry *old_obj_tail; 3657 Obj_Entry *obj; 3658 Objlist initlist; 3659 RtldLockState mlockstate; 3660 int result; 3661 3662 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3663 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3664 refobj->path, lo_flags, mode); 3665 objlist_init(&initlist); 3666 3667 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3668 wlock_acquire(rtld_bind_lock, &mlockstate); 3669 lockstate = &mlockstate; 3670 } 3671 GDB_STATE(RT_ADD,NULL); 3672 3673 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3674 obj = NULL; 3675 if (name == NULL && fd == -1) { 3676 obj = obj_main; 3677 obj->refcount++; 3678 } else { 3679 obj = load_object(name, fd, refobj, lo_flags); 3680 } 3681 3682 if (obj) { 3683 obj->dl_refcount++; 3684 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3685 objlist_push_tail(&list_global, obj); 3686 if (globallist_next(old_obj_tail) != NULL) { 3687 /* We loaded something new. */ 3688 assert(globallist_next(old_obj_tail) == obj); 3689 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3690 obj->symbolic = true; 3691 result = 0; 3692 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3693 obj->static_tls && !allocate_tls_offset(obj)) { 3694 _rtld_error("%s: No space available " 3695 "for static Thread Local Storage", obj->path); 3696 result = -1; 3697 } 3698 if (result != -1) 3699 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3700 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3701 init_dag(obj); 3702 ref_dag(obj); 3703 if (result != -1) 3704 result = rtld_verify_versions(&obj->dagmembers); 3705 if (result != -1 && ld_tracing) 3706 goto trace; 3707 if (result == -1 || relocate_object_dag(obj, 3708 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3709 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3710 lockstate) == -1) { 3711 dlopen_cleanup(obj, lockstate); 3712 obj = NULL; 3713 } else if (lo_flags & RTLD_LO_EARLY) { 3714 /* 3715 * Do not call the init functions for early loaded 3716 * filtees. The image is still not initialized enough 3717 * for them to work. 3718 * 3719 * Our object is found by the global object list and 3720 * will be ordered among all init calls done right 3721 * before transferring control to main. 3722 */ 3723 } else { 3724 /* Make list of init functions to call. */ 3725 initlist_add_objects(obj, obj, &initlist); 3726 } 3727 /* 3728 * Process all no_delete or global objects here, given 3729 * them own DAGs to prevent their dependencies from being 3730 * unloaded. This has to be done after we have loaded all 3731 * of the dependencies, so that we do not miss any. 3732 */ 3733 if (obj != NULL) 3734 process_z(obj); 3735 } else { 3736 /* 3737 * Bump the reference counts for objects on this DAG. If 3738 * this is the first dlopen() call for the object that was 3739 * already loaded as a dependency, initialize the dag 3740 * starting at it. 3741 */ 3742 init_dag(obj); 3743 ref_dag(obj); 3744 3745 if ((lo_flags & RTLD_LO_TRACE) != 0) 3746 goto trace; 3747 } 3748 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3749 obj->z_nodelete) && !obj->ref_nodel) { 3750 dbg("obj %s nodelete", obj->path); 3751 ref_dag(obj); 3752 obj->z_nodelete = obj->ref_nodel = true; 3753 } 3754 } 3755 3756 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3757 name); 3758 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3759 3760 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3761 map_stacks_exec(lockstate); 3762 if (obj != NULL) 3763 distribute_static_tls(&initlist, lockstate); 3764 } 3765 3766 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3767 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3768 lockstate) == -1) { 3769 objlist_clear(&initlist); 3770 dlopen_cleanup(obj, lockstate); 3771 if (lockstate == &mlockstate) 3772 lock_release(rtld_bind_lock, lockstate); 3773 return (NULL); 3774 } 3775 3776 if (!(lo_flags & RTLD_LO_EARLY)) { 3777 /* Call the init functions. */ 3778 objlist_call_init(&initlist, lockstate); 3779 } 3780 objlist_clear(&initlist); 3781 if (lockstate == &mlockstate) 3782 lock_release(rtld_bind_lock, lockstate); 3783 return (obj); 3784 trace: 3785 trace_loaded_objects(obj); 3786 if (lockstate == &mlockstate) 3787 lock_release(rtld_bind_lock, lockstate); 3788 exit(0); 3789 } 3790 3791 static void * 3792 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3793 int flags) 3794 { 3795 DoneList donelist; 3796 const Obj_Entry *obj, *defobj; 3797 const Elf_Sym *def; 3798 SymLook req; 3799 RtldLockState lockstate; 3800 tls_index ti; 3801 void *sym; 3802 int res; 3803 3804 def = NULL; 3805 defobj = NULL; 3806 symlook_init(&req, name); 3807 req.ventry = ve; 3808 req.flags = flags | SYMLOOK_IN_PLT; 3809 req.lockstate = &lockstate; 3810 3811 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3812 rlock_acquire(rtld_bind_lock, &lockstate); 3813 if (sigsetjmp(lockstate.env, 0) != 0) 3814 lock_upgrade(rtld_bind_lock, &lockstate); 3815 if (handle == NULL || handle == RTLD_NEXT || 3816 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3817 3818 if ((obj = obj_from_addr(retaddr)) == NULL) { 3819 _rtld_error("Cannot determine caller's shared object"); 3820 lock_release(rtld_bind_lock, &lockstate); 3821 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3822 return (NULL); 3823 } 3824 if (handle == NULL) { /* Just the caller's shared object. */ 3825 res = symlook_obj(&req, obj); 3826 if (res == 0) { 3827 def = req.sym_out; 3828 defobj = req.defobj_out; 3829 } 3830 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3831 handle == RTLD_SELF) { /* ... caller included */ 3832 if (handle == RTLD_NEXT) 3833 obj = globallist_next(obj); 3834 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3835 if (obj->marker) 3836 continue; 3837 res = symlook_obj(&req, obj); 3838 if (res == 0) { 3839 if (def == NULL || (ld_dynamic_weak && 3840 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) { 3841 def = req.sym_out; 3842 defobj = req.defobj_out; 3843 if (!ld_dynamic_weak || 3844 ELF_ST_BIND(def->st_info) != STB_WEAK) 3845 break; 3846 } 3847 } 3848 } 3849 /* 3850 * Search the dynamic linker itself, and possibly resolve the 3851 * symbol from there. This is how the application links to 3852 * dynamic linker services such as dlopen. 3853 * Note that we ignore ld_dynamic_weak == false case, 3854 * always overriding weak symbols by rtld definitions. 3855 */ 3856 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3857 res = symlook_obj(&req, &obj_rtld); 3858 if (res == 0) { 3859 def = req.sym_out; 3860 defobj = req.defobj_out; 3861 } 3862 } 3863 } else { 3864 assert(handle == RTLD_DEFAULT); 3865 res = symlook_default(&req, obj); 3866 if (res == 0) { 3867 defobj = req.defobj_out; 3868 def = req.sym_out; 3869 } 3870 } 3871 } else { 3872 if ((obj = dlcheck(handle)) == NULL) { 3873 lock_release(rtld_bind_lock, &lockstate); 3874 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3875 return (NULL); 3876 } 3877 3878 donelist_init(&donelist); 3879 if (obj->mainprog) { 3880 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3881 res = symlook_global(&req, &donelist); 3882 if (res == 0) { 3883 def = req.sym_out; 3884 defobj = req.defobj_out; 3885 } 3886 /* 3887 * Search the dynamic linker itself, and possibly resolve the 3888 * symbol from there. This is how the application links to 3889 * dynamic linker services such as dlopen. 3890 */ 3891 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3892 res = symlook_obj(&req, &obj_rtld); 3893 if (res == 0) { 3894 def = req.sym_out; 3895 defobj = req.defobj_out; 3896 } 3897 } 3898 } 3899 else { 3900 /* Search the whole DAG rooted at the given object. */ 3901 res = symlook_list(&req, &obj->dagmembers, &donelist); 3902 if (res == 0) { 3903 def = req.sym_out; 3904 defobj = req.defobj_out; 3905 } 3906 } 3907 } 3908 3909 if (def != NULL) { 3910 lock_release(rtld_bind_lock, &lockstate); 3911 3912 /* 3913 * The value required by the caller is derived from the value 3914 * of the symbol. this is simply the relocated value of the 3915 * symbol. 3916 */ 3917 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3918 sym = make_function_pointer(def, defobj); 3919 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3920 sym = rtld_resolve_ifunc(defobj, def); 3921 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3922 ti.ti_module = defobj->tlsindex; 3923 ti.ti_offset = def->st_value; 3924 sym = __tls_get_addr(&ti); 3925 } else 3926 sym = defobj->relocbase + def->st_value; 3927 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3928 return (sym); 3929 } 3930 3931 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3932 ve != NULL ? ve->name : ""); 3933 lock_release(rtld_bind_lock, &lockstate); 3934 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3935 return (NULL); 3936 } 3937 3938 void * 3939 dlsym(void *handle, const char *name) 3940 { 3941 return (do_dlsym(handle, name, __builtin_return_address(0), NULL, 3942 SYMLOOK_DLSYM)); 3943 } 3944 3945 dlfunc_t 3946 dlfunc(void *handle, const char *name) 3947 { 3948 union { 3949 void *d; 3950 dlfunc_t f; 3951 } rv; 3952 3953 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3954 SYMLOOK_DLSYM); 3955 return (rv.f); 3956 } 3957 3958 void * 3959 dlvsym(void *handle, const char *name, const char *version) 3960 { 3961 Ver_Entry ventry; 3962 3963 ventry.name = version; 3964 ventry.file = NULL; 3965 ventry.hash = elf_hash(version); 3966 ventry.flags= 0; 3967 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3968 SYMLOOK_DLSYM)); 3969 } 3970 3971 int 3972 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3973 { 3974 const Obj_Entry *obj; 3975 RtldLockState lockstate; 3976 3977 rlock_acquire(rtld_bind_lock, &lockstate); 3978 obj = obj_from_addr(addr); 3979 if (obj == NULL) { 3980 _rtld_error("No shared object contains address"); 3981 lock_release(rtld_bind_lock, &lockstate); 3982 return (0); 3983 } 3984 rtld_fill_dl_phdr_info(obj, phdr_info); 3985 lock_release(rtld_bind_lock, &lockstate); 3986 return (1); 3987 } 3988 3989 int 3990 dladdr(const void *addr, Dl_info *info) 3991 { 3992 const Obj_Entry *obj; 3993 const Elf_Sym *def; 3994 void *symbol_addr; 3995 unsigned long symoffset; 3996 RtldLockState lockstate; 3997 3998 rlock_acquire(rtld_bind_lock, &lockstate); 3999 obj = obj_from_addr(addr); 4000 if (obj == NULL) { 4001 _rtld_error("No shared object contains address"); 4002 lock_release(rtld_bind_lock, &lockstate); 4003 return (0); 4004 } 4005 info->dli_fname = obj->path; 4006 info->dli_fbase = obj->mapbase; 4007 info->dli_saddr = (void *)0; 4008 info->dli_sname = NULL; 4009 4010 /* 4011 * Walk the symbol list looking for the symbol whose address is 4012 * closest to the address sent in. 4013 */ 4014 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 4015 def = obj->symtab + symoffset; 4016 4017 /* 4018 * For skip the symbol if st_shndx is either SHN_UNDEF or 4019 * SHN_COMMON. 4020 */ 4021 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 4022 continue; 4023 4024 /* 4025 * If the symbol is greater than the specified address, or if it 4026 * is further away from addr than the current nearest symbol, 4027 * then reject it. 4028 */ 4029 symbol_addr = obj->relocbase + def->st_value; 4030 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 4031 continue; 4032 4033 /* Update our idea of the nearest symbol. */ 4034 info->dli_sname = obj->strtab + def->st_name; 4035 info->dli_saddr = symbol_addr; 4036 4037 /* Exact match? */ 4038 if (info->dli_saddr == addr) 4039 break; 4040 } 4041 lock_release(rtld_bind_lock, &lockstate); 4042 return (1); 4043 } 4044 4045 int 4046 dlinfo(void *handle, int request, void *p) 4047 { 4048 const Obj_Entry *obj; 4049 RtldLockState lockstate; 4050 int error; 4051 4052 rlock_acquire(rtld_bind_lock, &lockstate); 4053 4054 if (handle == NULL || handle == RTLD_SELF) { 4055 void *retaddr; 4056 4057 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 4058 if ((obj = obj_from_addr(retaddr)) == NULL) 4059 _rtld_error("Cannot determine caller's shared object"); 4060 } else 4061 obj = dlcheck(handle); 4062 4063 if (obj == NULL) { 4064 lock_release(rtld_bind_lock, &lockstate); 4065 return (-1); 4066 } 4067 4068 error = 0; 4069 switch (request) { 4070 case RTLD_DI_LINKMAP: 4071 *((struct link_map const **)p) = &obj->linkmap; 4072 break; 4073 case RTLD_DI_ORIGIN: 4074 error = rtld_dirname(obj->path, p); 4075 break; 4076 4077 case RTLD_DI_SERINFOSIZE: 4078 case RTLD_DI_SERINFO: 4079 error = do_search_info(obj, request, (struct dl_serinfo *)p); 4080 break; 4081 4082 default: 4083 _rtld_error("Invalid request %d passed to dlinfo()", request); 4084 error = -1; 4085 } 4086 4087 lock_release(rtld_bind_lock, &lockstate); 4088 4089 return (error); 4090 } 4091 4092 static void 4093 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 4094 { 4095 Elf_Addr **dtvp; 4096 4097 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 4098 phdr_info->dlpi_name = obj->path; 4099 phdr_info->dlpi_phdr = obj->phdr; 4100 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 4101 phdr_info->dlpi_tls_modid = obj->tlsindex; 4102 dtvp = _get_tp(); 4103 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp, 4104 obj->tlsindex, 0, true) + TLS_DTV_OFFSET; 4105 phdr_info->dlpi_adds = obj_loads; 4106 phdr_info->dlpi_subs = obj_loads - obj_count; 4107 } 4108 4109 int 4110 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 4111 { 4112 struct dl_phdr_info phdr_info; 4113 Obj_Entry *obj, marker; 4114 RtldLockState bind_lockstate, phdr_lockstate; 4115 int error; 4116 4117 init_marker(&marker); 4118 error = 0; 4119 4120 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 4121 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4122 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 4123 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 4124 rtld_fill_dl_phdr_info(obj, &phdr_info); 4125 hold_object(obj); 4126 lock_release(rtld_bind_lock, &bind_lockstate); 4127 4128 error = callback(&phdr_info, sizeof phdr_info, param); 4129 4130 wlock_acquire(rtld_bind_lock, &bind_lockstate); 4131 unhold_object(obj); 4132 obj = globallist_next(&marker); 4133 TAILQ_REMOVE(&obj_list, &marker, next); 4134 if (error != 0) { 4135 lock_release(rtld_bind_lock, &bind_lockstate); 4136 lock_release(rtld_phdr_lock, &phdr_lockstate); 4137 return (error); 4138 } 4139 } 4140 4141 if (error == 0) { 4142 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 4143 lock_release(rtld_bind_lock, &bind_lockstate); 4144 error = callback(&phdr_info, sizeof(phdr_info), param); 4145 } 4146 lock_release(rtld_phdr_lock, &phdr_lockstate); 4147 return (error); 4148 } 4149 4150 static void * 4151 fill_search_info(const char *dir, size_t dirlen, void *param) 4152 { 4153 struct fill_search_info_args *arg; 4154 4155 arg = param; 4156 4157 if (arg->request == RTLD_DI_SERINFOSIZE) { 4158 arg->serinfo->dls_cnt ++; 4159 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 4160 } else { 4161 struct dl_serpath *s_entry; 4162 4163 s_entry = arg->serpath; 4164 s_entry->dls_name = arg->strspace; 4165 s_entry->dls_flags = arg->flags; 4166 4167 strncpy(arg->strspace, dir, dirlen); 4168 arg->strspace[dirlen] = '\0'; 4169 4170 arg->strspace += dirlen + 1; 4171 arg->serpath++; 4172 } 4173 4174 return (NULL); 4175 } 4176 4177 static int 4178 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 4179 { 4180 struct dl_serinfo _info; 4181 struct fill_search_info_args args; 4182 4183 args.request = RTLD_DI_SERINFOSIZE; 4184 args.serinfo = &_info; 4185 4186 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 4187 _info.dls_cnt = 0; 4188 4189 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 4190 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 4191 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 4192 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 4193 if (!obj->z_nodeflib) 4194 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4195 4196 4197 if (request == RTLD_DI_SERINFOSIZE) { 4198 info->dls_size = _info.dls_size; 4199 info->dls_cnt = _info.dls_cnt; 4200 return (0); 4201 } 4202 4203 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4204 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4205 return (-1); 4206 } 4207 4208 args.request = RTLD_DI_SERINFO; 4209 args.serinfo = info; 4210 args.serpath = &info->dls_serpath[0]; 4211 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4212 4213 args.flags = LA_SER_RUNPATH; 4214 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4215 return (-1); 4216 4217 args.flags = LA_SER_LIBPATH; 4218 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4219 return (-1); 4220 4221 args.flags = LA_SER_RUNPATH; 4222 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4223 return (-1); 4224 4225 args.flags = LA_SER_CONFIG; 4226 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4227 != NULL) 4228 return (-1); 4229 4230 args.flags = LA_SER_DEFAULT; 4231 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4232 fill_search_info, NULL, &args) != NULL) 4233 return (-1); 4234 return (0); 4235 } 4236 4237 static int 4238 rtld_dirname(const char *path, char *bname) 4239 { 4240 const char *endp; 4241 4242 /* Empty or NULL string gets treated as "." */ 4243 if (path == NULL || *path == '\0') { 4244 bname[0] = '.'; 4245 bname[1] = '\0'; 4246 return (0); 4247 } 4248 4249 /* Strip trailing slashes */ 4250 endp = path + strlen(path) - 1; 4251 while (endp > path && *endp == '/') 4252 endp--; 4253 4254 /* Find the start of the dir */ 4255 while (endp > path && *endp != '/') 4256 endp--; 4257 4258 /* Either the dir is "/" or there are no slashes */ 4259 if (endp == path) { 4260 bname[0] = *endp == '/' ? '/' : '.'; 4261 bname[1] = '\0'; 4262 return (0); 4263 } else { 4264 do { 4265 endp--; 4266 } while (endp > path && *endp == '/'); 4267 } 4268 4269 if (endp - path + 2 > PATH_MAX) 4270 { 4271 _rtld_error("Filename is too long: %s", path); 4272 return(-1); 4273 } 4274 4275 strncpy(bname, path, endp - path + 1); 4276 bname[endp - path + 1] = '\0'; 4277 return (0); 4278 } 4279 4280 static int 4281 rtld_dirname_abs(const char *path, char *base) 4282 { 4283 char *last; 4284 4285 if (realpath(path, base) == NULL) { 4286 _rtld_error("realpath \"%s\" failed (%s)", path, 4287 rtld_strerror(errno)); 4288 return (-1); 4289 } 4290 dbg("%s -> %s", path, base); 4291 last = strrchr(base, '/'); 4292 if (last == NULL) { 4293 _rtld_error("non-abs result from realpath \"%s\"", path); 4294 return (-1); 4295 } 4296 if (last != base) 4297 *last = '\0'; 4298 return (0); 4299 } 4300 4301 static void 4302 linkmap_add(Obj_Entry *obj) 4303 { 4304 struct link_map *l, *prev; 4305 4306 l = &obj->linkmap; 4307 l->l_name = obj->path; 4308 l->l_base = obj->mapbase; 4309 l->l_ld = obj->dynamic; 4310 l->l_addr = obj->relocbase; 4311 4312 if (r_debug.r_map == NULL) { 4313 r_debug.r_map = l; 4314 return; 4315 } 4316 4317 /* 4318 * Scan to the end of the list, but not past the entry for the 4319 * dynamic linker, which we want to keep at the very end. 4320 */ 4321 for (prev = r_debug.r_map; 4322 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4323 prev = prev->l_next) 4324 ; 4325 4326 /* Link in the new entry. */ 4327 l->l_prev = prev; 4328 l->l_next = prev->l_next; 4329 if (l->l_next != NULL) 4330 l->l_next->l_prev = l; 4331 prev->l_next = l; 4332 } 4333 4334 static void 4335 linkmap_delete(Obj_Entry *obj) 4336 { 4337 struct link_map *l; 4338 4339 l = &obj->linkmap; 4340 if (l->l_prev == NULL) { 4341 if ((r_debug.r_map = l->l_next) != NULL) 4342 l->l_next->l_prev = NULL; 4343 return; 4344 } 4345 4346 if ((l->l_prev->l_next = l->l_next) != NULL) 4347 l->l_next->l_prev = l->l_prev; 4348 } 4349 4350 /* 4351 * Function for the debugger to set a breakpoint on to gain control. 4352 * 4353 * The two parameters allow the debugger to easily find and determine 4354 * what the runtime loader is doing and to whom it is doing it. 4355 * 4356 * When the loadhook trap is hit (r_debug_state, set at program 4357 * initialization), the arguments can be found on the stack: 4358 * 4359 * +8 struct link_map *m 4360 * +4 struct r_debug *rd 4361 * +0 RetAddr 4362 */ 4363 void 4364 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4365 { 4366 /* 4367 * The following is a hack to force the compiler to emit calls to 4368 * this function, even when optimizing. If the function is empty, 4369 * the compiler is not obliged to emit any code for calls to it, 4370 * even when marked __noinline. However, gdb depends on those 4371 * calls being made. 4372 */ 4373 __compiler_membar(); 4374 } 4375 4376 /* 4377 * A function called after init routines have completed. This can be used to 4378 * break before a program's entry routine is called, and can be used when 4379 * main is not available in the symbol table. 4380 */ 4381 void 4382 _r_debug_postinit(struct link_map *m __unused) 4383 { 4384 4385 /* See r_debug_state(). */ 4386 __compiler_membar(); 4387 } 4388 4389 static void 4390 release_object(Obj_Entry *obj) 4391 { 4392 4393 if (obj->holdcount > 0) { 4394 obj->unholdfree = true; 4395 return; 4396 } 4397 munmap(obj->mapbase, obj->mapsize); 4398 linkmap_delete(obj); 4399 obj_free(obj); 4400 } 4401 4402 /* 4403 * Get address of the pointer variable in the main program. 4404 * Prefer non-weak symbol over the weak one. 4405 */ 4406 static const void ** 4407 get_program_var_addr(const char *name, RtldLockState *lockstate) 4408 { 4409 SymLook req; 4410 DoneList donelist; 4411 4412 symlook_init(&req, name); 4413 req.lockstate = lockstate; 4414 donelist_init(&donelist); 4415 if (symlook_global(&req, &donelist) != 0) 4416 return (NULL); 4417 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4418 return ((const void **)make_function_pointer(req.sym_out, 4419 req.defobj_out)); 4420 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4421 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4422 else 4423 return ((const void **)(req.defobj_out->relocbase + 4424 req.sym_out->st_value)); 4425 } 4426 4427 /* 4428 * Set a pointer variable in the main program to the given value. This 4429 * is used to set key variables such as "environ" before any of the 4430 * init functions are called. 4431 */ 4432 static void 4433 set_program_var(const char *name, const void *value) 4434 { 4435 const void **addr; 4436 4437 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4438 dbg("\"%s\": *%p <-- %p", name, addr, value); 4439 *addr = value; 4440 } 4441 } 4442 4443 /* 4444 * Search the global objects, including dependencies and main object, 4445 * for the given symbol. 4446 */ 4447 static int 4448 symlook_global(SymLook *req, DoneList *donelist) 4449 { 4450 SymLook req1; 4451 const Objlist_Entry *elm; 4452 int res; 4453 4454 symlook_init_from_req(&req1, req); 4455 4456 /* Search all objects loaded at program start up. */ 4457 if (req->defobj_out == NULL || (ld_dynamic_weak && 4458 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { 4459 res = symlook_list(&req1, &list_main, donelist); 4460 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || 4461 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4462 req->sym_out = req1.sym_out; 4463 req->defobj_out = req1.defobj_out; 4464 assert(req->defobj_out != NULL); 4465 } 4466 } 4467 4468 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4469 STAILQ_FOREACH(elm, &list_global, link) { 4470 if (req->defobj_out != NULL && (!ld_dynamic_weak || 4471 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4472 break; 4473 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4474 if (res == 0 && (req->defobj_out == NULL || 4475 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4476 req->sym_out = req1.sym_out; 4477 req->defobj_out = req1.defobj_out; 4478 assert(req->defobj_out != NULL); 4479 } 4480 } 4481 4482 return (req->sym_out != NULL ? 0 : ESRCH); 4483 } 4484 4485 /* 4486 * Given a symbol name in a referencing object, find the corresponding 4487 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4488 * no definition was found. Returns a pointer to the Obj_Entry of the 4489 * defining object via the reference parameter DEFOBJ_OUT. 4490 */ 4491 static int 4492 symlook_default(SymLook *req, const Obj_Entry *refobj) 4493 { 4494 DoneList donelist; 4495 const Objlist_Entry *elm; 4496 SymLook req1; 4497 int res; 4498 4499 donelist_init(&donelist); 4500 symlook_init_from_req(&req1, req); 4501 4502 /* 4503 * Look first in the referencing object if linked symbolically, 4504 * and similarly handle protected symbols. 4505 */ 4506 res = symlook_obj(&req1, refobj); 4507 if (res == 0 && (refobj->symbolic || 4508 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4509 req->sym_out = req1.sym_out; 4510 req->defobj_out = req1.defobj_out; 4511 assert(req->defobj_out != NULL); 4512 } 4513 if (refobj->symbolic || req->defobj_out != NULL) 4514 donelist_check(&donelist, refobj); 4515 4516 symlook_global(req, &donelist); 4517 4518 /* Search all dlopened DAGs containing the referencing object. */ 4519 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4520 if (req->sym_out != NULL && (!ld_dynamic_weak || 4521 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) 4522 break; 4523 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4524 if (res == 0 && (req->sym_out == NULL || 4525 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4526 req->sym_out = req1.sym_out; 4527 req->defobj_out = req1.defobj_out; 4528 assert(req->defobj_out != NULL); 4529 } 4530 } 4531 4532 /* 4533 * Search the dynamic linker itself, and possibly resolve the 4534 * symbol from there. This is how the application links to 4535 * dynamic linker services such as dlopen. 4536 */ 4537 if (req->sym_out == NULL || 4538 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4539 res = symlook_obj(&req1, &obj_rtld); 4540 if (res == 0) { 4541 req->sym_out = req1.sym_out; 4542 req->defobj_out = req1.defobj_out; 4543 assert(req->defobj_out != NULL); 4544 } 4545 } 4546 4547 return (req->sym_out != NULL ? 0 : ESRCH); 4548 } 4549 4550 static int 4551 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4552 { 4553 const Elf_Sym *def; 4554 const Obj_Entry *defobj; 4555 const Objlist_Entry *elm; 4556 SymLook req1; 4557 int res; 4558 4559 def = NULL; 4560 defobj = NULL; 4561 STAILQ_FOREACH(elm, objlist, link) { 4562 if (donelist_check(dlp, elm->obj)) 4563 continue; 4564 symlook_init_from_req(&req1, req); 4565 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4566 if (def == NULL || (ld_dynamic_weak && 4567 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4568 def = req1.sym_out; 4569 defobj = req1.defobj_out; 4570 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4571 break; 4572 } 4573 } 4574 } 4575 if (def != NULL) { 4576 req->sym_out = def; 4577 req->defobj_out = defobj; 4578 return (0); 4579 } 4580 return (ESRCH); 4581 } 4582 4583 /* 4584 * Search the chain of DAGS cointed to by the given Needed_Entry 4585 * for a symbol of the given name. Each DAG is scanned completely 4586 * before advancing to the next one. Returns a pointer to the symbol, 4587 * or NULL if no definition was found. 4588 */ 4589 static int 4590 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4591 { 4592 const Elf_Sym *def; 4593 const Needed_Entry *n; 4594 const Obj_Entry *defobj; 4595 SymLook req1; 4596 int res; 4597 4598 def = NULL; 4599 defobj = NULL; 4600 symlook_init_from_req(&req1, req); 4601 for (n = needed; n != NULL; n = n->next) { 4602 if (n->obj == NULL || 4603 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4604 continue; 4605 if (def == NULL || (ld_dynamic_weak && 4606 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4607 def = req1.sym_out; 4608 defobj = req1.defobj_out; 4609 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) 4610 break; 4611 } 4612 } 4613 if (def != NULL) { 4614 req->sym_out = def; 4615 req->defobj_out = defobj; 4616 return (0); 4617 } 4618 return (ESRCH); 4619 } 4620 4621 /* 4622 * Search the symbol table of a single shared object for a symbol of 4623 * the given name and version, if requested. Returns a pointer to the 4624 * symbol, or NULL if no definition was found. If the object is 4625 * filter, return filtered symbol from filtee. 4626 * 4627 * The symbol's hash value is passed in for efficiency reasons; that 4628 * eliminates many recomputations of the hash value. 4629 */ 4630 int 4631 symlook_obj(SymLook *req, const Obj_Entry *obj) 4632 { 4633 DoneList donelist; 4634 SymLook req1; 4635 int flags, res, mres; 4636 4637 /* 4638 * If there is at least one valid hash at this point, we prefer to 4639 * use the faster GNU version if available. 4640 */ 4641 if (obj->valid_hash_gnu) 4642 mres = symlook_obj1_gnu(req, obj); 4643 else if (obj->valid_hash_sysv) 4644 mres = symlook_obj1_sysv(req, obj); 4645 else 4646 return (EINVAL); 4647 4648 if (mres == 0) { 4649 if (obj->needed_filtees != NULL) { 4650 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4651 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4652 donelist_init(&donelist); 4653 symlook_init_from_req(&req1, req); 4654 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4655 if (res == 0) { 4656 req->sym_out = req1.sym_out; 4657 req->defobj_out = req1.defobj_out; 4658 } 4659 return (res); 4660 } 4661 if (obj->needed_aux_filtees != NULL) { 4662 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4663 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4664 donelist_init(&donelist); 4665 symlook_init_from_req(&req1, req); 4666 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4667 if (res == 0) { 4668 req->sym_out = req1.sym_out; 4669 req->defobj_out = req1.defobj_out; 4670 return (res); 4671 } 4672 } 4673 } 4674 return (mres); 4675 } 4676 4677 /* Symbol match routine common to both hash functions */ 4678 static bool 4679 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4680 const unsigned long symnum) 4681 { 4682 Elf_Versym verndx; 4683 const Elf_Sym *symp; 4684 const char *strp; 4685 4686 symp = obj->symtab + symnum; 4687 strp = obj->strtab + symp->st_name; 4688 4689 switch (ELF_ST_TYPE(symp->st_info)) { 4690 case STT_FUNC: 4691 case STT_NOTYPE: 4692 case STT_OBJECT: 4693 case STT_COMMON: 4694 case STT_GNU_IFUNC: 4695 if (symp->st_value == 0) 4696 return (false); 4697 /* fallthrough */ 4698 case STT_TLS: 4699 if (symp->st_shndx != SHN_UNDEF) 4700 break; 4701 #ifndef __mips__ 4702 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4703 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4704 break; 4705 #endif 4706 /* fallthrough */ 4707 default: 4708 return (false); 4709 } 4710 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4711 return (false); 4712 4713 if (req->ventry == NULL) { 4714 if (obj->versyms != NULL) { 4715 verndx = VER_NDX(obj->versyms[symnum]); 4716 if (verndx > obj->vernum) { 4717 _rtld_error( 4718 "%s: symbol %s references wrong version %d", 4719 obj->path, obj->strtab + symnum, verndx); 4720 return (false); 4721 } 4722 /* 4723 * If we are not called from dlsym (i.e. this 4724 * is a normal relocation from unversioned 4725 * binary), accept the symbol immediately if 4726 * it happens to have first version after this 4727 * shared object became versioned. Otherwise, 4728 * if symbol is versioned and not hidden, 4729 * remember it. If it is the only symbol with 4730 * this name exported by the shared object, it 4731 * will be returned as a match by the calling 4732 * function. If symbol is global (verndx < 2) 4733 * accept it unconditionally. 4734 */ 4735 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4736 verndx == VER_NDX_GIVEN) { 4737 result->sym_out = symp; 4738 return (true); 4739 } 4740 else if (verndx >= VER_NDX_GIVEN) { 4741 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4742 == 0) { 4743 if (result->vsymp == NULL) 4744 result->vsymp = symp; 4745 result->vcount++; 4746 } 4747 return (false); 4748 } 4749 } 4750 result->sym_out = symp; 4751 return (true); 4752 } 4753 if (obj->versyms == NULL) { 4754 if (object_match_name(obj, req->ventry->name)) { 4755 _rtld_error("%s: object %s should provide version %s " 4756 "for symbol %s", obj_rtld.path, obj->path, 4757 req->ventry->name, obj->strtab + symnum); 4758 return (false); 4759 } 4760 } else { 4761 verndx = VER_NDX(obj->versyms[symnum]); 4762 if (verndx > obj->vernum) { 4763 _rtld_error("%s: symbol %s references wrong version %d", 4764 obj->path, obj->strtab + symnum, verndx); 4765 return (false); 4766 } 4767 if (obj->vertab[verndx].hash != req->ventry->hash || 4768 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4769 /* 4770 * Version does not match. Look if this is a 4771 * global symbol and if it is not hidden. If 4772 * global symbol (verndx < 2) is available, 4773 * use it. Do not return symbol if we are 4774 * called by dlvsym, because dlvsym looks for 4775 * a specific version and default one is not 4776 * what dlvsym wants. 4777 */ 4778 if ((req->flags & SYMLOOK_DLSYM) || 4779 (verndx >= VER_NDX_GIVEN) || 4780 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4781 return (false); 4782 } 4783 } 4784 result->sym_out = symp; 4785 return (true); 4786 } 4787 4788 /* 4789 * Search for symbol using SysV hash function. 4790 * obj->buckets is known not to be NULL at this point; the test for this was 4791 * performed with the obj->valid_hash_sysv assignment. 4792 */ 4793 static int 4794 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4795 { 4796 unsigned long symnum; 4797 Sym_Match_Result matchres; 4798 4799 matchres.sym_out = NULL; 4800 matchres.vsymp = NULL; 4801 matchres.vcount = 0; 4802 4803 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4804 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4805 if (symnum >= obj->nchains) 4806 return (ESRCH); /* Bad object */ 4807 4808 if (matched_symbol(req, obj, &matchres, symnum)) { 4809 req->sym_out = matchres.sym_out; 4810 req->defobj_out = obj; 4811 return (0); 4812 } 4813 } 4814 if (matchres.vcount == 1) { 4815 req->sym_out = matchres.vsymp; 4816 req->defobj_out = obj; 4817 return (0); 4818 } 4819 return (ESRCH); 4820 } 4821 4822 /* Search for symbol using GNU hash function */ 4823 static int 4824 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4825 { 4826 Elf_Addr bloom_word; 4827 const Elf32_Word *hashval; 4828 Elf32_Word bucket; 4829 Sym_Match_Result matchres; 4830 unsigned int h1, h2; 4831 unsigned long symnum; 4832 4833 matchres.sym_out = NULL; 4834 matchres.vsymp = NULL; 4835 matchres.vcount = 0; 4836 4837 /* Pick right bitmask word from Bloom filter array */ 4838 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4839 obj->maskwords_bm_gnu]; 4840 4841 /* Calculate modulus word size of gnu hash and its derivative */ 4842 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4843 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4844 4845 /* Filter out the "definitely not in set" queries */ 4846 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4847 return (ESRCH); 4848 4849 /* Locate hash chain and corresponding value element*/ 4850 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4851 if (bucket == 0) 4852 return (ESRCH); 4853 hashval = &obj->chain_zero_gnu[bucket]; 4854 do { 4855 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4856 symnum = hashval - obj->chain_zero_gnu; 4857 if (matched_symbol(req, obj, &matchres, symnum)) { 4858 req->sym_out = matchres.sym_out; 4859 req->defobj_out = obj; 4860 return (0); 4861 } 4862 } 4863 } while ((*hashval++ & 1) == 0); 4864 if (matchres.vcount == 1) { 4865 req->sym_out = matchres.vsymp; 4866 req->defobj_out = obj; 4867 return (0); 4868 } 4869 return (ESRCH); 4870 } 4871 4872 static void 4873 trace_loaded_objects(Obj_Entry *obj) 4874 { 4875 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4876 int c; 4877 4878 if ((main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME)) == 4879 NULL) 4880 main_local = ""; 4881 4882 if ((fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1)) == NULL) 4883 fmt1 = "\t%o => %p (%x)\n"; 4884 4885 if ((fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2)) == NULL) 4886 fmt2 = "\t%o (%x)\n"; 4887 4888 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL); 4889 4890 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4891 Needed_Entry *needed; 4892 const char *name, *path; 4893 bool is_lib; 4894 4895 if (obj->marker) 4896 continue; 4897 if (list_containers && obj->needed != NULL) 4898 rtld_printf("%s:\n", obj->path); 4899 for (needed = obj->needed; needed; needed = needed->next) { 4900 if (needed->obj != NULL) { 4901 if (needed->obj->traced && !list_containers) 4902 continue; 4903 needed->obj->traced = true; 4904 path = needed->obj->path; 4905 } else 4906 path = "not found"; 4907 4908 name = obj->strtab + needed->name; 4909 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4910 4911 fmt = is_lib ? fmt1 : fmt2; 4912 while ((c = *fmt++) != '\0') { 4913 switch (c) { 4914 default: 4915 rtld_putchar(c); 4916 continue; 4917 case '\\': 4918 switch (c = *fmt) { 4919 case '\0': 4920 continue; 4921 case 'n': 4922 rtld_putchar('\n'); 4923 break; 4924 case 't': 4925 rtld_putchar('\t'); 4926 break; 4927 } 4928 break; 4929 case '%': 4930 switch (c = *fmt) { 4931 case '\0': 4932 continue; 4933 case '%': 4934 default: 4935 rtld_putchar(c); 4936 break; 4937 case 'A': 4938 rtld_putstr(main_local); 4939 break; 4940 case 'a': 4941 rtld_putstr(obj_main->path); 4942 break; 4943 case 'o': 4944 rtld_putstr(name); 4945 break; 4946 #if 0 4947 case 'm': 4948 rtld_printf("%d", sodp->sod_major); 4949 break; 4950 case 'n': 4951 rtld_printf("%d", sodp->sod_minor); 4952 break; 4953 #endif 4954 case 'p': 4955 rtld_putstr(path); 4956 break; 4957 case 'x': 4958 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4959 0); 4960 break; 4961 } 4962 break; 4963 } 4964 ++fmt; 4965 } 4966 } 4967 } 4968 } 4969 4970 /* 4971 * Unload a dlopened object and its dependencies from memory and from 4972 * our data structures. It is assumed that the DAG rooted in the 4973 * object has already been unreferenced, and that the object has a 4974 * reference count of 0. 4975 */ 4976 static void 4977 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4978 { 4979 Obj_Entry marker, *obj, *next; 4980 4981 assert(root->refcount == 0); 4982 4983 /* 4984 * Pass over the DAG removing unreferenced objects from 4985 * appropriate lists. 4986 */ 4987 unlink_object(root); 4988 4989 /* Unmap all objects that are no longer referenced. */ 4990 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4991 next = TAILQ_NEXT(obj, next); 4992 if (obj->marker || obj->refcount != 0) 4993 continue; 4994 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4995 obj->mapsize, 0, obj->path); 4996 dbg("unloading \"%s\"", obj->path); 4997 /* 4998 * Unlink the object now to prevent new references from 4999 * being acquired while the bind lock is dropped in 5000 * recursive dlclose() invocations. 5001 */ 5002 TAILQ_REMOVE(&obj_list, obj, next); 5003 obj_count--; 5004 5005 if (obj->filtees_loaded) { 5006 if (next != NULL) { 5007 init_marker(&marker); 5008 TAILQ_INSERT_BEFORE(next, &marker, next); 5009 unload_filtees(obj, lockstate); 5010 next = TAILQ_NEXT(&marker, next); 5011 TAILQ_REMOVE(&obj_list, &marker, next); 5012 } else 5013 unload_filtees(obj, lockstate); 5014 } 5015 release_object(obj); 5016 } 5017 } 5018 5019 static void 5020 unlink_object(Obj_Entry *root) 5021 { 5022 Objlist_Entry *elm; 5023 5024 if (root->refcount == 0) { 5025 /* Remove the object from the RTLD_GLOBAL list. */ 5026 objlist_remove(&list_global, root); 5027 5028 /* Remove the object from all objects' DAG lists. */ 5029 STAILQ_FOREACH(elm, &root->dagmembers, link) { 5030 objlist_remove(&elm->obj->dldags, root); 5031 if (elm->obj != root) 5032 unlink_object(elm->obj); 5033 } 5034 } 5035 } 5036 5037 static void 5038 ref_dag(Obj_Entry *root) 5039 { 5040 Objlist_Entry *elm; 5041 5042 assert(root->dag_inited); 5043 STAILQ_FOREACH(elm, &root->dagmembers, link) 5044 elm->obj->refcount++; 5045 } 5046 5047 static void 5048 unref_dag(Obj_Entry *root) 5049 { 5050 Objlist_Entry *elm; 5051 5052 assert(root->dag_inited); 5053 STAILQ_FOREACH(elm, &root->dagmembers, link) 5054 elm->obj->refcount--; 5055 } 5056 5057 /* 5058 * Common code for MD __tls_get_addr(). 5059 */ 5060 static void * 5061 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked) 5062 { 5063 Elf_Addr *newdtv, *dtv; 5064 RtldLockState lockstate; 5065 int to_copy; 5066 5067 dtv = *dtvp; 5068 /* Check dtv generation in case new modules have arrived */ 5069 if (dtv[0] != tls_dtv_generation) { 5070 if (!locked) 5071 wlock_acquire(rtld_bind_lock, &lockstate); 5072 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5073 to_copy = dtv[1]; 5074 if (to_copy > tls_max_index) 5075 to_copy = tls_max_index; 5076 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 5077 newdtv[0] = tls_dtv_generation; 5078 newdtv[1] = tls_max_index; 5079 free(dtv); 5080 if (!locked) 5081 lock_release(rtld_bind_lock, &lockstate); 5082 dtv = *dtvp = newdtv; 5083 } 5084 5085 /* Dynamically allocate module TLS if necessary */ 5086 if (dtv[index + 1] == 0) { 5087 /* Signal safe, wlock will block out signals. */ 5088 if (!locked) 5089 wlock_acquire(rtld_bind_lock, &lockstate); 5090 if (!dtv[index + 1]) 5091 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 5092 if (!locked) 5093 lock_release(rtld_bind_lock, &lockstate); 5094 } 5095 return ((void *)(dtv[index + 1] + offset)); 5096 } 5097 5098 void * 5099 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 5100 { 5101 Elf_Addr *dtv; 5102 5103 dtv = *dtvp; 5104 /* Check dtv generation in case new modules have arrived */ 5105 if (__predict_true(dtv[0] == tls_dtv_generation && 5106 dtv[index + 1] != 0)) 5107 return ((void *)(dtv[index + 1] + offset)); 5108 return (tls_get_addr_slow(dtvp, index, offset, false)); 5109 } 5110 5111 #ifdef TLS_VARIANT_I 5112 5113 /* 5114 * Return pointer to allocated TLS block 5115 */ 5116 static void * 5117 get_tls_block_ptr(void *tcb, size_t tcbsize) 5118 { 5119 size_t extra_size, post_size, pre_size, tls_block_size; 5120 size_t tls_init_align; 5121 5122 tls_init_align = MAX(obj_main->tlsalign, 1); 5123 5124 /* Compute fragments sizes. */ 5125 extra_size = tcbsize - TLS_TCB_SIZE; 5126 post_size = calculate_tls_post_size(tls_init_align); 5127 tls_block_size = tcbsize + post_size; 5128 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5129 5130 return ((char *)tcb - pre_size - extra_size); 5131 } 5132 5133 /* 5134 * Allocate Static TLS using the Variant I method. 5135 * 5136 * For details on the layout, see lib/libc/gen/tls.c. 5137 * 5138 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 5139 * it is based on tls_last_offset, and TLS offsets here are really TCB 5140 * offsets, whereas libc's tls_static_space is just the executable's static 5141 * TLS segment. 5142 */ 5143 void * 5144 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 5145 { 5146 Obj_Entry *obj; 5147 char *tls_block; 5148 Elf_Addr *dtv, **tcb; 5149 Elf_Addr addr; 5150 Elf_Addr i; 5151 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 5152 size_t tls_init_align, tls_init_offset; 5153 5154 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 5155 return (oldtcb); 5156 5157 assert(tcbsize >= TLS_TCB_SIZE); 5158 maxalign = MAX(tcbalign, tls_static_max_align); 5159 tls_init_align = MAX(obj_main->tlsalign, 1); 5160 5161 /* Compute fragmets sizes. */ 5162 extra_size = tcbsize - TLS_TCB_SIZE; 5163 post_size = calculate_tls_post_size(tls_init_align); 5164 tls_block_size = tcbsize + post_size; 5165 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 5166 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 5167 5168 /* Allocate whole TLS block */ 5169 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 5170 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 5171 5172 if (oldtcb != NULL) { 5173 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 5174 tls_static_space); 5175 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 5176 5177 /* Adjust the DTV. */ 5178 dtv = tcb[0]; 5179 for (i = 0; i < dtv[1]; i++) { 5180 if (dtv[i+2] >= (Elf_Addr)oldtcb && 5181 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 5182 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 5183 } 5184 } 5185 } else { 5186 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5187 tcb[0] = dtv; 5188 dtv[0] = tls_dtv_generation; 5189 dtv[1] = tls_max_index; 5190 5191 for (obj = globallist_curr(objs); obj != NULL; 5192 obj = globallist_next(obj)) { 5193 if (obj->tlsoffset == 0) 5194 continue; 5195 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 5196 addr = (Elf_Addr)tcb + obj->tlsoffset; 5197 if (tls_init_offset > 0) 5198 memset((void *)addr, 0, tls_init_offset); 5199 if (obj->tlsinitsize > 0) { 5200 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5201 obj->tlsinitsize); 5202 } 5203 if (obj->tlssize > obj->tlsinitsize) { 5204 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5205 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5206 } 5207 dtv[obj->tlsindex + 1] = addr; 5208 } 5209 } 5210 5211 return (tcb); 5212 } 5213 5214 void 5215 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5216 { 5217 Elf_Addr *dtv; 5218 Elf_Addr tlsstart, tlsend; 5219 size_t post_size; 5220 size_t dtvsize, i, tls_init_align; 5221 5222 assert(tcbsize >= TLS_TCB_SIZE); 5223 tls_init_align = MAX(obj_main->tlsalign, 1); 5224 5225 /* Compute fragments sizes. */ 5226 post_size = calculate_tls_post_size(tls_init_align); 5227 5228 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5229 tlsend = (Elf_Addr)tcb + tls_static_space; 5230 5231 dtv = *(Elf_Addr **)tcb; 5232 dtvsize = dtv[1]; 5233 for (i = 0; i < dtvsize; i++) { 5234 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5235 free((void*)dtv[i+2]); 5236 } 5237 } 5238 free(dtv); 5239 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5240 } 5241 5242 #endif /* TLS_VARIANT_I */ 5243 5244 #ifdef TLS_VARIANT_II 5245 5246 /* 5247 * Allocate Static TLS using the Variant II method. 5248 */ 5249 void * 5250 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5251 { 5252 Obj_Entry *obj; 5253 size_t size, ralign; 5254 char *tls; 5255 Elf_Addr *dtv, *olddtv; 5256 Elf_Addr segbase, oldsegbase, addr; 5257 size_t i; 5258 5259 ralign = tcbalign; 5260 if (tls_static_max_align > ralign) 5261 ralign = tls_static_max_align; 5262 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5263 5264 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5265 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5266 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5267 5268 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5269 ((Elf_Addr *)segbase)[0] = segbase; 5270 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv; 5271 5272 dtv[0] = tls_dtv_generation; 5273 dtv[1] = tls_max_index; 5274 5275 if (oldtls) { 5276 /* 5277 * Copy the static TLS block over whole. 5278 */ 5279 oldsegbase = (Elf_Addr) oldtls; 5280 memcpy((void *)(segbase - tls_static_space), 5281 (const void *)(oldsegbase - tls_static_space), 5282 tls_static_space); 5283 5284 /* 5285 * If any dynamic TLS blocks have been created tls_get_addr(), 5286 * move them over. 5287 */ 5288 olddtv = ((Elf_Addr **)oldsegbase)[1]; 5289 for (i = 0; i < olddtv[1]; i++) { 5290 if (olddtv[i + 2] < oldsegbase - size || 5291 olddtv[i + 2] > oldsegbase) { 5292 dtv[i + 2] = olddtv[i + 2]; 5293 olddtv[i + 2] = 0; 5294 } 5295 } 5296 5297 /* 5298 * We assume that this block was the one we created with 5299 * allocate_initial_tls(). 5300 */ 5301 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr)); 5302 } else { 5303 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5304 if (obj->marker || obj->tlsoffset == 0) 5305 continue; 5306 addr = segbase - obj->tlsoffset; 5307 memset((void *)(addr + obj->tlsinitsize), 5308 0, obj->tlssize - obj->tlsinitsize); 5309 if (obj->tlsinit) { 5310 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize); 5311 obj->static_tls_copied = true; 5312 } 5313 dtv[obj->tlsindex + 1] = addr; 5314 } 5315 } 5316 5317 return ((void *)segbase); 5318 } 5319 5320 void 5321 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5322 { 5323 Elf_Addr* dtv; 5324 size_t size, ralign; 5325 int dtvsize, i; 5326 Elf_Addr tlsstart, tlsend; 5327 5328 /* 5329 * Figure out the size of the initial TLS block so that we can 5330 * find stuff which ___tls_get_addr() allocated dynamically. 5331 */ 5332 ralign = tcbalign; 5333 if (tls_static_max_align > ralign) 5334 ralign = tls_static_max_align; 5335 size = roundup(tls_static_space, ralign); 5336 5337 dtv = ((Elf_Addr **)tls)[1]; 5338 dtvsize = dtv[1]; 5339 tlsend = (Elf_Addr)tls; 5340 tlsstart = tlsend - size; 5341 for (i = 0; i < dtvsize; i++) { 5342 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || 5343 dtv[i + 2] > tlsend)) { 5344 free_aligned((void *)dtv[i + 2]); 5345 } 5346 } 5347 5348 free_aligned((void *)tlsstart); 5349 free((void *)dtv); 5350 } 5351 5352 #endif /* TLS_VARIANT_II */ 5353 5354 /* 5355 * Allocate TLS block for module with given index. 5356 */ 5357 void * 5358 allocate_module_tls(int index) 5359 { 5360 Obj_Entry *obj; 5361 char *p; 5362 5363 TAILQ_FOREACH(obj, &obj_list, next) { 5364 if (obj->marker) 5365 continue; 5366 if (obj->tlsindex == index) 5367 break; 5368 } 5369 if (obj == NULL) { 5370 _rtld_error("Can't find module with TLS index %d", index); 5371 rtld_die(); 5372 } 5373 5374 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5375 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5376 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5377 return (p); 5378 } 5379 5380 bool 5381 allocate_tls_offset(Obj_Entry *obj) 5382 { 5383 size_t off; 5384 5385 if (obj->tls_done) 5386 return (true); 5387 5388 if (obj->tlssize == 0) { 5389 obj->tls_done = true; 5390 return (true); 5391 } 5392 5393 if (tls_last_offset == 0) 5394 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5395 obj->tlspoffset); 5396 else 5397 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5398 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5399 5400 obj->tlsoffset = off; 5401 #ifdef TLS_VARIANT_I 5402 off += obj->tlssize; 5403 #endif 5404 5405 /* 5406 * If we have already fixed the size of the static TLS block, we 5407 * must stay within that size. When allocating the static TLS, we 5408 * leave a small amount of space spare to be used for dynamically 5409 * loading modules which use static TLS. 5410 */ 5411 if (tls_static_space != 0) { 5412 if (off > tls_static_space) 5413 return (false); 5414 } else if (obj->tlsalign > tls_static_max_align) { 5415 tls_static_max_align = obj->tlsalign; 5416 } 5417 5418 tls_last_offset = off; 5419 tls_last_size = obj->tlssize; 5420 obj->tls_done = true; 5421 5422 return (true); 5423 } 5424 5425 void 5426 free_tls_offset(Obj_Entry *obj) 5427 { 5428 5429 /* 5430 * If we were the last thing to allocate out of the static TLS 5431 * block, we give our space back to the 'allocator'. This is a 5432 * simplistic workaround to allow libGL.so.1 to be loaded and 5433 * unloaded multiple times. 5434 */ 5435 size_t off = obj->tlsoffset; 5436 #ifdef TLS_VARIANT_I 5437 off += obj->tlssize; 5438 #endif 5439 if (off == tls_last_offset) { 5440 tls_last_offset -= obj->tlssize; 5441 tls_last_size = 0; 5442 } 5443 } 5444 5445 void * 5446 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5447 { 5448 void *ret; 5449 RtldLockState lockstate; 5450 5451 wlock_acquire(rtld_bind_lock, &lockstate); 5452 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5453 tcbsize, tcbalign); 5454 lock_release(rtld_bind_lock, &lockstate); 5455 return (ret); 5456 } 5457 5458 void 5459 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5460 { 5461 RtldLockState lockstate; 5462 5463 wlock_acquire(rtld_bind_lock, &lockstate); 5464 free_tls(tcb, tcbsize, tcbalign); 5465 lock_release(rtld_bind_lock, &lockstate); 5466 } 5467 5468 static void 5469 object_add_name(Obj_Entry *obj, const char *name) 5470 { 5471 Name_Entry *entry; 5472 size_t len; 5473 5474 len = strlen(name); 5475 entry = malloc(sizeof(Name_Entry) + len); 5476 5477 if (entry != NULL) { 5478 strcpy(entry->name, name); 5479 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5480 } 5481 } 5482 5483 static int 5484 object_match_name(const Obj_Entry *obj, const char *name) 5485 { 5486 Name_Entry *entry; 5487 5488 STAILQ_FOREACH(entry, &obj->names, link) { 5489 if (strcmp(name, entry->name) == 0) 5490 return (1); 5491 } 5492 return (0); 5493 } 5494 5495 static Obj_Entry * 5496 locate_dependency(const Obj_Entry *obj, const char *name) 5497 { 5498 const Objlist_Entry *entry; 5499 const Needed_Entry *needed; 5500 5501 STAILQ_FOREACH(entry, &list_main, link) { 5502 if (object_match_name(entry->obj, name)) 5503 return (entry->obj); 5504 } 5505 5506 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5507 if (strcmp(obj->strtab + needed->name, name) == 0 || 5508 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5509 /* 5510 * If there is DT_NEEDED for the name we are looking for, 5511 * we are all set. Note that object might not be found if 5512 * dependency was not loaded yet, so the function can 5513 * return NULL here. This is expected and handled 5514 * properly by the caller. 5515 */ 5516 return (needed->obj); 5517 } 5518 } 5519 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5520 obj->path, name); 5521 rtld_die(); 5522 } 5523 5524 static int 5525 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5526 const Elf_Vernaux *vna) 5527 { 5528 const Elf_Verdef *vd; 5529 const char *vername; 5530 5531 vername = refobj->strtab + vna->vna_name; 5532 vd = depobj->verdef; 5533 if (vd == NULL) { 5534 _rtld_error("%s: version %s required by %s not defined", 5535 depobj->path, vername, refobj->path); 5536 return (-1); 5537 } 5538 for (;;) { 5539 if (vd->vd_version != VER_DEF_CURRENT) { 5540 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5541 depobj->path, vd->vd_version); 5542 return (-1); 5543 } 5544 if (vna->vna_hash == vd->vd_hash) { 5545 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5546 ((const char *)vd + vd->vd_aux); 5547 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5548 return (0); 5549 } 5550 if (vd->vd_next == 0) 5551 break; 5552 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5553 } 5554 if (vna->vna_flags & VER_FLG_WEAK) 5555 return (0); 5556 _rtld_error("%s: version %s required by %s not found", 5557 depobj->path, vername, refobj->path); 5558 return (-1); 5559 } 5560 5561 static int 5562 rtld_verify_object_versions(Obj_Entry *obj) 5563 { 5564 const Elf_Verneed *vn; 5565 const Elf_Verdef *vd; 5566 const Elf_Verdaux *vda; 5567 const Elf_Vernaux *vna; 5568 const Obj_Entry *depobj; 5569 int maxvernum, vernum; 5570 5571 if (obj->ver_checked) 5572 return (0); 5573 obj->ver_checked = true; 5574 5575 maxvernum = 0; 5576 /* 5577 * Walk over defined and required version records and figure out 5578 * max index used by any of them. Do very basic sanity checking 5579 * while there. 5580 */ 5581 vn = obj->verneed; 5582 while (vn != NULL) { 5583 if (vn->vn_version != VER_NEED_CURRENT) { 5584 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5585 obj->path, vn->vn_version); 5586 return (-1); 5587 } 5588 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5589 for (;;) { 5590 vernum = VER_NEED_IDX(vna->vna_other); 5591 if (vernum > maxvernum) 5592 maxvernum = vernum; 5593 if (vna->vna_next == 0) 5594 break; 5595 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5596 } 5597 if (vn->vn_next == 0) 5598 break; 5599 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5600 } 5601 5602 vd = obj->verdef; 5603 while (vd != NULL) { 5604 if (vd->vd_version != VER_DEF_CURRENT) { 5605 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5606 obj->path, vd->vd_version); 5607 return (-1); 5608 } 5609 vernum = VER_DEF_IDX(vd->vd_ndx); 5610 if (vernum > maxvernum) 5611 maxvernum = vernum; 5612 if (vd->vd_next == 0) 5613 break; 5614 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5615 } 5616 5617 if (maxvernum == 0) 5618 return (0); 5619 5620 /* 5621 * Store version information in array indexable by version index. 5622 * Verify that object version requirements are satisfied along the 5623 * way. 5624 */ 5625 obj->vernum = maxvernum + 1; 5626 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5627 5628 vd = obj->verdef; 5629 while (vd != NULL) { 5630 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5631 vernum = VER_DEF_IDX(vd->vd_ndx); 5632 assert(vernum <= maxvernum); 5633 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5634 obj->vertab[vernum].hash = vd->vd_hash; 5635 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5636 obj->vertab[vernum].file = NULL; 5637 obj->vertab[vernum].flags = 0; 5638 } 5639 if (vd->vd_next == 0) 5640 break; 5641 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5642 } 5643 5644 vn = obj->verneed; 5645 while (vn != NULL) { 5646 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5647 if (depobj == NULL) 5648 return (-1); 5649 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5650 for (;;) { 5651 if (check_object_provided_version(obj, depobj, vna)) 5652 return (-1); 5653 vernum = VER_NEED_IDX(vna->vna_other); 5654 assert(vernum <= maxvernum); 5655 obj->vertab[vernum].hash = vna->vna_hash; 5656 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5657 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5658 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5659 VER_INFO_HIDDEN : 0; 5660 if (vna->vna_next == 0) 5661 break; 5662 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5663 } 5664 if (vn->vn_next == 0) 5665 break; 5666 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5667 } 5668 return (0); 5669 } 5670 5671 static int 5672 rtld_verify_versions(const Objlist *objlist) 5673 { 5674 Objlist_Entry *entry; 5675 int rc; 5676 5677 rc = 0; 5678 STAILQ_FOREACH(entry, objlist, link) { 5679 /* 5680 * Skip dummy objects or objects that have their version requirements 5681 * already checked. 5682 */ 5683 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5684 continue; 5685 if (rtld_verify_object_versions(entry->obj) == -1) { 5686 rc = -1; 5687 if (ld_tracing == NULL) 5688 break; 5689 } 5690 } 5691 if (rc == 0 || ld_tracing != NULL) 5692 rc = rtld_verify_object_versions(&obj_rtld); 5693 return (rc); 5694 } 5695 5696 const Ver_Entry * 5697 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5698 { 5699 Elf_Versym vernum; 5700 5701 if (obj->vertab) { 5702 vernum = VER_NDX(obj->versyms[symnum]); 5703 if (vernum >= obj->vernum) { 5704 _rtld_error("%s: symbol %s has wrong verneed value %d", 5705 obj->path, obj->strtab + symnum, vernum); 5706 } else if (obj->vertab[vernum].hash != 0) { 5707 return (&obj->vertab[vernum]); 5708 } 5709 } 5710 return (NULL); 5711 } 5712 5713 int 5714 _rtld_get_stack_prot(void) 5715 { 5716 5717 return (stack_prot); 5718 } 5719 5720 int 5721 _rtld_is_dlopened(void *arg) 5722 { 5723 Obj_Entry *obj; 5724 RtldLockState lockstate; 5725 int res; 5726 5727 rlock_acquire(rtld_bind_lock, &lockstate); 5728 obj = dlcheck(arg); 5729 if (obj == NULL) 5730 obj = obj_from_addr(arg); 5731 if (obj == NULL) { 5732 _rtld_error("No shared object contains address"); 5733 lock_release(rtld_bind_lock, &lockstate); 5734 return (-1); 5735 } 5736 res = obj->dlopened ? 1 : 0; 5737 lock_release(rtld_bind_lock, &lockstate); 5738 return (res); 5739 } 5740 5741 static int 5742 obj_remap_relro(Obj_Entry *obj, int prot) 5743 { 5744 5745 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5746 prot) == -1) { 5747 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5748 obj->path, prot, rtld_strerror(errno)); 5749 return (-1); 5750 } 5751 return (0); 5752 } 5753 5754 static int 5755 obj_disable_relro(Obj_Entry *obj) 5756 { 5757 5758 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5759 } 5760 5761 static int 5762 obj_enforce_relro(Obj_Entry *obj) 5763 { 5764 5765 return (obj_remap_relro(obj, PROT_READ)); 5766 } 5767 5768 static void 5769 map_stacks_exec(RtldLockState *lockstate) 5770 { 5771 void (*thr_map_stacks_exec)(void); 5772 5773 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5774 return; 5775 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5776 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5777 if (thr_map_stacks_exec != NULL) { 5778 stack_prot |= PROT_EXEC; 5779 thr_map_stacks_exec(); 5780 } 5781 } 5782 5783 static void 5784 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5785 { 5786 Objlist_Entry *elm; 5787 Obj_Entry *obj; 5788 void (*distrib)(size_t, void *, size_t, size_t); 5789 5790 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5791 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5792 if (distrib == NULL) 5793 return; 5794 STAILQ_FOREACH(elm, list, link) { 5795 obj = elm->obj; 5796 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5797 continue; 5798 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5799 obj->tlssize); 5800 obj->static_tls_copied = true; 5801 } 5802 } 5803 5804 void 5805 symlook_init(SymLook *dst, const char *name) 5806 { 5807 5808 bzero(dst, sizeof(*dst)); 5809 dst->name = name; 5810 dst->hash = elf_hash(name); 5811 dst->hash_gnu = gnu_hash(name); 5812 } 5813 5814 static void 5815 symlook_init_from_req(SymLook *dst, const SymLook *src) 5816 { 5817 5818 dst->name = src->name; 5819 dst->hash = src->hash; 5820 dst->hash_gnu = src->hash_gnu; 5821 dst->ventry = src->ventry; 5822 dst->flags = src->flags; 5823 dst->defobj_out = NULL; 5824 dst->sym_out = NULL; 5825 dst->lockstate = src->lockstate; 5826 } 5827 5828 static int 5829 open_binary_fd(const char *argv0, bool search_in_path, 5830 const char **binpath_res) 5831 { 5832 char *binpath, *pathenv, *pe, *res1; 5833 const char *res; 5834 int fd; 5835 5836 binpath = NULL; 5837 res = NULL; 5838 if (search_in_path && strchr(argv0, '/') == NULL) { 5839 binpath = xmalloc(PATH_MAX); 5840 pathenv = getenv("PATH"); 5841 if (pathenv == NULL) { 5842 _rtld_error("-p and no PATH environment variable"); 5843 rtld_die(); 5844 } 5845 pathenv = strdup(pathenv); 5846 if (pathenv == NULL) { 5847 _rtld_error("Cannot allocate memory"); 5848 rtld_die(); 5849 } 5850 fd = -1; 5851 errno = ENOENT; 5852 while ((pe = strsep(&pathenv, ":")) != NULL) { 5853 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5854 continue; 5855 if (binpath[0] != '\0' && 5856 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5857 continue; 5858 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5859 continue; 5860 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5861 if (fd != -1 || errno != ENOENT) { 5862 res = binpath; 5863 break; 5864 } 5865 } 5866 free(pathenv); 5867 } else { 5868 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5869 res = argv0; 5870 } 5871 5872 if (fd == -1) { 5873 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5874 rtld_die(); 5875 } 5876 if (res != NULL && res[0] != '/') { 5877 res1 = xmalloc(PATH_MAX); 5878 if (realpath(res, res1) != NULL) { 5879 if (res != argv0) 5880 free(__DECONST(char *, res)); 5881 res = res1; 5882 } else { 5883 free(res1); 5884 } 5885 } 5886 *binpath_res = res; 5887 return (fd); 5888 } 5889 5890 /* 5891 * Parse a set of command-line arguments. 5892 */ 5893 static int 5894 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5895 const char **argv0, bool *dir_ignore) 5896 { 5897 const char *arg; 5898 char machine[64]; 5899 size_t sz; 5900 int arglen, fd, i, j, mib[2]; 5901 char opt; 5902 bool seen_b, seen_f; 5903 5904 dbg("Parsing command-line arguments"); 5905 *use_pathp = false; 5906 *fdp = -1; 5907 *dir_ignore = false; 5908 seen_b = seen_f = false; 5909 5910 for (i = 1; i < argc; i++ ) { 5911 arg = argv[i]; 5912 dbg("argv[%d]: '%s'", i, arg); 5913 5914 /* 5915 * rtld arguments end with an explicit "--" or with the first 5916 * non-prefixed argument. 5917 */ 5918 if (strcmp(arg, "--") == 0) { 5919 i++; 5920 break; 5921 } 5922 if (arg[0] != '-') 5923 break; 5924 5925 /* 5926 * All other arguments are single-character options that can 5927 * be combined, so we need to search through `arg` for them. 5928 */ 5929 arglen = strlen(arg); 5930 for (j = 1; j < arglen; j++) { 5931 opt = arg[j]; 5932 if (opt == 'h') { 5933 print_usage(argv[0]); 5934 _exit(0); 5935 } else if (opt == 'b') { 5936 if (seen_f) { 5937 _rtld_error("Both -b and -f specified"); 5938 rtld_die(); 5939 } 5940 i++; 5941 *argv0 = argv[i]; 5942 seen_b = true; 5943 break; 5944 } else if (opt == 'd') { 5945 *dir_ignore = true; 5946 break; 5947 } else if (opt == 'f') { 5948 if (seen_b) { 5949 _rtld_error("Both -b and -f specified"); 5950 rtld_die(); 5951 } 5952 5953 /* 5954 * -f XX can be used to specify a 5955 * descriptor for the binary named at 5956 * the command line (i.e., the later 5957 * argument will specify the process 5958 * name but the descriptor is what 5959 * will actually be executed). 5960 * 5961 * -f must be the last option in, e.g., -abcf. 5962 */ 5963 if (j != arglen - 1) { 5964 _rtld_error("Invalid options: %s", arg); 5965 rtld_die(); 5966 } 5967 i++; 5968 fd = parse_integer(argv[i]); 5969 if (fd == -1) { 5970 _rtld_error( 5971 "Invalid file descriptor: '%s'", 5972 argv[i]); 5973 rtld_die(); 5974 } 5975 *fdp = fd; 5976 seen_f = true; 5977 break; 5978 } else if (opt == 'p') { 5979 *use_pathp = true; 5980 } else if (opt == 'u') { 5981 trust = false; 5982 } else if (opt == 'v') { 5983 machine[0] = '\0'; 5984 mib[0] = CTL_HW; 5985 mib[1] = HW_MACHINE; 5986 sz = sizeof(machine); 5987 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5988 ld_elf_hints_path = ld_get_env_var( 5989 LD_ELF_HINTS_PATH); 5990 set_ld_elf_hints_path(); 5991 rtld_printf( 5992 "FreeBSD ld-elf.so.1 %s\n" 5993 "FreeBSD_version %d\n" 5994 "Default lib path %s\n" 5995 "Hints lib path %s\n" 5996 "Env prefix %s\n" 5997 "Default hint file %s\n" 5998 "Hint file %s\n" 5999 "libmap file %s\n", 6000 machine, 6001 __FreeBSD_version, ld_standard_library_path, 6002 gethints(false), 6003 ld_env_prefix, ld_elf_hints_default, 6004 ld_elf_hints_path, 6005 ld_path_libmap_conf); 6006 _exit(0); 6007 } else { 6008 _rtld_error("Invalid argument: '%s'", arg); 6009 print_usage(argv[0]); 6010 rtld_die(); 6011 } 6012 } 6013 } 6014 6015 if (!seen_b) 6016 *argv0 = argv[i]; 6017 return (i); 6018 } 6019 6020 /* 6021 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 6022 */ 6023 static int 6024 parse_integer(const char *str) 6025 { 6026 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 6027 const char *orig; 6028 int n; 6029 char c; 6030 6031 orig = str; 6032 n = 0; 6033 for (c = *str; c != '\0'; c = *++str) { 6034 if (c < '0' || c > '9') 6035 return (-1); 6036 6037 n *= RADIX; 6038 n += c - '0'; 6039 } 6040 6041 /* Make sure we actually parsed something. */ 6042 if (str == orig) 6043 return (-1); 6044 return (n); 6045 } 6046 6047 static void 6048 print_usage(const char *argv0) 6049 { 6050 6051 rtld_printf( 6052 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n" 6053 "\n" 6054 "Options:\n" 6055 " -h Display this help message\n" 6056 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 6057 " -d Ignore lack of exec permissions for the binary\n" 6058 " -f <FD> Execute <FD> instead of searching for <binary>\n" 6059 " -p Search in PATH for named binary\n" 6060 " -u Ignore LD_ environment variables\n" 6061 " -v Display identification information\n" 6062 " -- End of RTLD options\n" 6063 " <binary> Name of process to execute\n" 6064 " <args> Arguments to the executed process\n", argv0); 6065 } 6066 6067 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } 6068 static const struct auxfmt { 6069 const char *name; 6070 const char *fmt; 6071 } auxfmts[] = { 6072 AUXFMT(AT_NULL, NULL), 6073 AUXFMT(AT_IGNORE, NULL), 6074 AUXFMT(AT_EXECFD, "%ld"), 6075 AUXFMT(AT_PHDR, "%p"), 6076 AUXFMT(AT_PHENT, "%lu"), 6077 AUXFMT(AT_PHNUM, "%lu"), 6078 AUXFMT(AT_PAGESZ, "%lu"), 6079 AUXFMT(AT_BASE, "%#lx"), 6080 AUXFMT(AT_FLAGS, "%#lx"), 6081 AUXFMT(AT_ENTRY, "%p"), 6082 AUXFMT(AT_NOTELF, NULL), 6083 AUXFMT(AT_UID, "%ld"), 6084 AUXFMT(AT_EUID, "%ld"), 6085 AUXFMT(AT_GID, "%ld"), 6086 AUXFMT(AT_EGID, "%ld"), 6087 AUXFMT(AT_EXECPATH, "%s"), 6088 AUXFMT(AT_CANARY, "%p"), 6089 AUXFMT(AT_CANARYLEN, "%lu"), 6090 AUXFMT(AT_OSRELDATE, "%lu"), 6091 AUXFMT(AT_NCPUS, "%lu"), 6092 AUXFMT(AT_PAGESIZES, "%p"), 6093 AUXFMT(AT_PAGESIZESLEN, "%lu"), 6094 AUXFMT(AT_TIMEKEEP, "%p"), 6095 AUXFMT(AT_STACKPROT, "%#lx"), 6096 AUXFMT(AT_EHDRFLAGS, "%#lx"), 6097 AUXFMT(AT_HWCAP, "%#lx"), 6098 AUXFMT(AT_HWCAP2, "%#lx"), 6099 AUXFMT(AT_BSDFLAGS, "%#lx"), 6100 AUXFMT(AT_ARGC, "%lu"), 6101 AUXFMT(AT_ARGV, "%p"), 6102 AUXFMT(AT_ENVC, "%p"), 6103 AUXFMT(AT_ENVV, "%p"), 6104 AUXFMT(AT_PS_STRINGS, "%p"), 6105 AUXFMT(AT_FXRNG, "%p"), 6106 }; 6107 6108 static bool 6109 is_ptr_fmt(const char *fmt) 6110 { 6111 char last; 6112 6113 last = fmt[strlen(fmt) - 1]; 6114 return (last == 'p' || last == 's'); 6115 } 6116 6117 static void 6118 dump_auxv(Elf_Auxinfo **aux_info) 6119 { 6120 Elf_Auxinfo *auxp; 6121 const struct auxfmt *fmt; 6122 int i; 6123 6124 for (i = 0; i < AT_COUNT; i++) { 6125 auxp = aux_info[i]; 6126 if (auxp == NULL) 6127 continue; 6128 fmt = &auxfmts[i]; 6129 if (fmt->fmt == NULL) 6130 continue; 6131 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); 6132 if (is_ptr_fmt(fmt->fmt)) { 6133 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6134 auxp->a_un.a_ptr); 6135 } else { 6136 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, 6137 auxp->a_un.a_val); 6138 } 6139 rtld_fdprintf(STDOUT_FILENO, "\n"); 6140 } 6141 } 6142 6143 /* 6144 * Overrides for libc_pic-provided functions. 6145 */ 6146 6147 int 6148 __getosreldate(void) 6149 { 6150 size_t len; 6151 int oid[2]; 6152 int error, osrel; 6153 6154 if (osreldate != 0) 6155 return (osreldate); 6156 6157 oid[0] = CTL_KERN; 6158 oid[1] = KERN_OSRELDATE; 6159 osrel = 0; 6160 len = sizeof(osrel); 6161 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 6162 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 6163 osreldate = osrel; 6164 return (osreldate); 6165 } 6166 const char * 6167 rtld_strerror(int errnum) 6168 { 6169 6170 if (errnum < 0 || errnum >= sys_nerr) 6171 return ("Unknown error"); 6172 return (sys_errlist[errnum]); 6173 } 6174 6175 char * 6176 getenv(const char *name) 6177 { 6178 return (__DECONST(char *, rtld_get_env_val(environ, name, 6179 strlen(name)))); 6180 } 6181 6182 /* malloc */ 6183 void * 6184 malloc(size_t nbytes) 6185 { 6186 6187 return (__crt_malloc(nbytes)); 6188 } 6189 6190 void * 6191 calloc(size_t num, size_t size) 6192 { 6193 6194 return (__crt_calloc(num, size)); 6195 } 6196 6197 void 6198 free(void *cp) 6199 { 6200 6201 __crt_free(cp); 6202 } 6203 6204 void * 6205 realloc(void *cp, size_t nbytes) 6206 { 6207 6208 return (__crt_realloc(cp, nbytes)); 6209 } 6210 6211 extern int _rtld_version__FreeBSD_version __exported; 6212 int _rtld_version__FreeBSD_version = __FreeBSD_version; 6213 6214 extern char _rtld_version_laddr_offset __exported; 6215 char _rtld_version_laddr_offset; 6216 6217 extern char _rtld_version_dlpi_tls_data __exported; 6218 char _rtld_version_dlpi_tls_data; 6219