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 "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 85 /* 86 * Function declarations. 87 */ 88 static const char *basename(const char *); 89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 90 const Elf_Dyn **, const Elf_Dyn **); 91 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 92 const Elf_Dyn *); 93 static bool digest_dynamic(Obj_Entry *, int); 94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 95 static void distribute_static_tls(Objlist *, RtldLockState *); 96 static Obj_Entry *dlcheck(void *); 97 static int dlclose_locked(void *, RtldLockState *); 98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 99 int lo_flags, int mode, RtldLockState *lockstate); 100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 102 static bool donelist_check(DoneList *, const Obj_Entry *); 103 static void errmsg_restore(char *); 104 static char *errmsg_save(void); 105 static void *fill_search_info(const char *, size_t, void *); 106 static char *find_library(const char *, const Obj_Entry *, int *); 107 static const char *gethints(bool); 108 static void hold_object(Obj_Entry *); 109 static void unhold_object(Obj_Entry *); 110 static void init_dag(Obj_Entry *); 111 static void init_marker(Obj_Entry *); 112 static void init_pagesizes(Elf_Auxinfo **aux_info); 113 static void init_rtld(caddr_t, Elf_Auxinfo **); 114 static void initlist_add_neededs(Needed_Entry *, Objlist *); 115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 117 static void linkmap_add(Obj_Entry *); 118 static void linkmap_delete(Obj_Entry *); 119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 120 static void unload_filtees(Obj_Entry *, RtldLockState *); 121 static int load_needed_objects(Obj_Entry *, int); 122 static int load_preload_objects(void); 123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 124 static void map_stacks_exec(RtldLockState *); 125 static int obj_disable_relro(Obj_Entry *); 126 static int obj_enforce_relro(Obj_Entry *); 127 static Obj_Entry *obj_from_addr(const void *); 128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 129 static void objlist_call_init(Objlist *, RtldLockState *); 130 static void objlist_clear(Objlist *); 131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 132 static void objlist_init(Objlist *); 133 static void objlist_push_head(Objlist *, Obj_Entry *); 134 static void objlist_push_tail(Objlist *, Obj_Entry *); 135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 136 static void objlist_remove(Objlist *, Obj_Entry *); 137 static int open_binary_fd(const char *argv0, bool search_in_path, 138 const char **binpath_res); 139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 140 const char **argv0); 141 static int parse_integer(const char *); 142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 143 static void print_usage(const char *argv0); 144 static void release_object(Obj_Entry *); 145 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 148 int flags, RtldLockState *lockstate); 149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 150 RtldLockState *); 151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 152 static int rtld_dirname(const char *, char *); 153 static int rtld_dirname_abs(const char *, char *); 154 static void *rtld_dlopen(const char *name, int fd, int mode); 155 static void rtld_exit(void); 156 static void rtld_nop_exit(void); 157 static char *search_library_path(const char *, const char *, const char *, 158 int *); 159 static char *search_library_pathfds(const char *, const char *, int *); 160 static const void **get_program_var_addr(const char *, RtldLockState *); 161 static void set_program_var(const char *, const void *); 162 static int symlook_default(SymLook *, const Obj_Entry *refobj); 163 static int symlook_global(SymLook *, DoneList *); 164 static void symlook_init_from_req(SymLook *, const SymLook *); 165 static int symlook_list(SymLook *, const Objlist *, DoneList *); 166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 169 static void trace_loaded_objects(Obj_Entry *); 170 static void unlink_object(Obj_Entry *); 171 static void unload_object(Obj_Entry *, RtldLockState *lockstate); 172 static void unref_dag(Obj_Entry *); 173 static void ref_dag(Obj_Entry *); 174 static char *origin_subst_one(Obj_Entry *, char *, const char *, 175 const char *, bool); 176 static char *origin_subst(Obj_Entry *, const char *); 177 static bool obj_resolve_origin(Obj_Entry *obj); 178 static void preinit_main(void); 179 static int rtld_verify_versions(const Objlist *); 180 static int rtld_verify_object_versions(Obj_Entry *); 181 static void object_add_name(Obj_Entry *, const char *); 182 static int object_match_name(const Obj_Entry *, const char *); 183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 185 struct dl_phdr_info *phdr_info); 186 static uint32_t gnu_hash(const char *); 187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 188 const unsigned long); 189 190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 191 void _r_debug_postinit(struct link_map *) __noinline __exported; 192 193 int __sys_openat(int, const char *, int, ...); 194 195 /* 196 * Data declarations. 197 */ 198 static char *error_message; /* Message for dlerror(), or NULL */ 199 struct r_debug r_debug __exported; /* for GDB; */ 200 static bool libmap_disable; /* Disable libmap */ 201 static bool ld_loadfltr; /* Immediate filters processing */ 202 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 203 static bool trust; /* False for setuid and setgid programs */ 204 static bool dangerous_ld_env; /* True if environment variables have been 205 used to affect the libraries loaded */ 206 bool ld_bind_not; /* Disable PLT update */ 207 static char *ld_bind_now; /* Environment variable for immediate binding */ 208 static char *ld_debug; /* Environment variable for debugging */ 209 static char *ld_library_path; /* Environment variable for search path */ 210 static char *ld_library_dirs; /* Environment variable for library descriptors */ 211 static char *ld_preload; /* Environment variable for libraries to 212 load first */ 213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 214 static const char *ld_tracing; /* Called from ldd to print libs */ 215 static char *ld_utrace; /* Use utrace() to log events. */ 216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 217 static Obj_Entry *obj_main; /* The main program shared object */ 218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 219 static unsigned int obj_count; /* Number of objects in obj_list */ 220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 221 222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 223 STAILQ_HEAD_INITIALIZER(list_global); 224 static Objlist list_main = /* Objects loaded at program startup */ 225 STAILQ_HEAD_INITIALIZER(list_main); 226 static Objlist list_fini = /* Objects needing fini() calls */ 227 STAILQ_HEAD_INITIALIZER(list_fini); 228 229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 230 231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 232 233 extern Elf_Dyn _DYNAMIC; 234 #pragma weak _DYNAMIC 235 236 int dlclose(void *) __exported; 237 char *dlerror(void) __exported; 238 void *dlopen(const char *, int) __exported; 239 void *fdlopen(int, int) __exported; 240 void *dlsym(void *, const char *) __exported; 241 dlfunc_t dlfunc(void *, const char *) __exported; 242 void *dlvsym(void *, const char *, const char *) __exported; 243 int dladdr(const void *, Dl_info *) __exported; 244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 246 int dlinfo(void *, int , void *) __exported; 247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 249 int _rtld_get_stack_prot(void) __exported; 250 int _rtld_is_dlopened(void *) __exported; 251 void _rtld_error(const char *, ...) __exported; 252 253 /* Only here to fix -Wmissing-prototypes warnings */ 254 int __getosreldate(void); 255 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); 256 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); 257 258 259 int npagesizes; 260 static int osreldate; 261 size_t *pagesizes; 262 263 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 264 static int max_stack_flags; 265 266 /* 267 * Global declarations normally provided by crt1. The dynamic linker is 268 * not built with crt1, so we have to provide them ourselves. 269 */ 270 char *__progname; 271 char **environ; 272 273 /* 274 * Used to pass argc, argv to init functions. 275 */ 276 int main_argc; 277 char **main_argv; 278 279 /* 280 * Globals to control TLS allocation. 281 */ 282 size_t tls_last_offset; /* Static TLS offset of last module */ 283 size_t tls_last_size; /* Static TLS size of last module */ 284 size_t tls_static_space; /* Static TLS space allocated */ 285 static size_t tls_static_max_align; 286 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 287 int tls_max_index = 1; /* Largest module index allocated */ 288 289 static bool ld_library_path_rpath = false; 290 bool ld_fast_sigblock = false; 291 292 /* 293 * Globals for path names, and such 294 */ 295 const char *ld_elf_hints_default = _PATH_ELF_HINTS; 296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 297 const char *ld_path_rtld = _PATH_RTLD; 298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 299 const char *ld_env_prefix = LD_; 300 301 static void (*rtld_exit_ptr)(void); 302 303 /* 304 * Fill in a DoneList with an allocation large enough to hold all of 305 * the currently-loaded objects. Keep this as a macro since it calls 306 * alloca and we want that to occur within the scope of the caller. 307 */ 308 #define donelist_init(dlp) \ 309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 310 assert((dlp)->objs != NULL), \ 311 (dlp)->num_alloc = obj_count, \ 312 (dlp)->num_used = 0) 313 314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 315 if (ld_utrace != NULL) \ 316 ld_utrace_log(e, h, mb, ms, r, n); \ 317 } while (0) 318 319 static void 320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 321 int refcnt, const char *name) 322 { 323 struct utrace_rtld ut; 324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 325 326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 327 ut.event = event; 328 ut.handle = handle; 329 ut.mapbase = mapbase; 330 ut.mapsize = mapsize; 331 ut.refcnt = refcnt; 332 bzero(ut.name, sizeof(ut.name)); 333 if (name) 334 strlcpy(ut.name, name, sizeof(ut.name)); 335 utrace(&ut, sizeof(ut)); 336 } 337 338 #ifdef RTLD_VARIANT_ENV_NAMES 339 /* 340 * construct the env variable based on the type of binary that's 341 * running. 342 */ 343 static inline const char * 344 _LD(const char *var) 345 { 346 static char buffer[128]; 347 348 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 349 strlcat(buffer, var, sizeof(buffer)); 350 return (buffer); 351 } 352 #else 353 #define _LD(x) LD_ x 354 #endif 355 356 /* 357 * Main entry point for dynamic linking. The first argument is the 358 * stack pointer. The stack is expected to be laid out as described 359 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 360 * Specifically, the stack pointer points to a word containing 361 * ARGC. Following that in the stack is a null-terminated sequence 362 * of pointers to argument strings. Then comes a null-terminated 363 * sequence of pointers to environment strings. Finally, there is a 364 * sequence of "auxiliary vector" entries. 365 * 366 * The second argument points to a place to store the dynamic linker's 367 * exit procedure pointer and the third to a place to store the main 368 * program's object. 369 * 370 * The return value is the main program's entry point. 371 */ 372 func_ptr_type 373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 374 { 375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 376 Objlist_Entry *entry; 377 Obj_Entry *last_interposer, *obj, *preload_tail; 378 const Elf_Phdr *phdr; 379 Objlist initlist; 380 RtldLockState lockstate; 381 struct stat st; 382 Elf_Addr *argcp; 383 char **argv, **env, **envp, *kexecpath, *library_path_rpath; 384 const char *argv0, *binpath; 385 caddr_t imgentry; 386 char buf[MAXPATHLEN]; 387 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; 388 size_t sz; 389 #ifdef __powerpc__ 390 int old_auxv_format = 1; 391 #endif 392 bool dir_enable, direct_exec, explicit_fd, search_in_path; 393 394 /* 395 * On entry, the dynamic linker itself has not been relocated yet. 396 * Be very careful not to reference any global data until after 397 * init_rtld has returned. It is OK to reference file-scope statics 398 * and string constants, and to call static and global functions. 399 */ 400 401 /* Find the auxiliary vector on the stack. */ 402 argcp = sp; 403 argc = *sp++; 404 argv = (char **) sp; 405 sp += argc + 1; /* Skip over arguments and NULL terminator */ 406 env = (char **) sp; 407 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 408 ; 409 aux = (Elf_Auxinfo *) sp; 410 411 /* Digest the auxiliary vector. */ 412 for (i = 0; i < AT_COUNT; i++) 413 aux_info[i] = NULL; 414 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 415 if (auxp->a_type < AT_COUNT) 416 aux_info[auxp->a_type] = auxp; 417 #ifdef __powerpc__ 418 if (auxp->a_type == 23) /* AT_STACKPROT */ 419 old_auxv_format = 0; 420 #endif 421 } 422 423 #ifdef __powerpc__ 424 if (old_auxv_format) { 425 /* Remap from old-style auxv numbers. */ 426 aux_info[23] = aux_info[21]; /* AT_STACKPROT */ 427 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */ 428 aux_info[19] = aux_info[17]; /* AT_NCPUS */ 429 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */ 430 aux_info[15] = aux_info[13]; /* AT_EXECPATH */ 431 aux_info[13] = NULL; /* AT_GID */ 432 433 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */ 434 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */ 435 aux_info[16] = aux_info[14]; /* AT_CANARY */ 436 aux_info[14] = NULL; /* AT_EGID */ 437 } 438 #endif 439 440 /* Initialize and relocate ourselves. */ 441 assert(aux_info[AT_BASE] != NULL); 442 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 443 444 __progname = obj_rtld.path; 445 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 446 environ = env; 447 main_argc = argc; 448 main_argv = argv; 449 450 if (aux_info[AT_BSDFLAGS] != NULL && 451 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) 452 ld_fast_sigblock = true; 453 454 trust = !issetugid(); 455 direct_exec = false; 456 457 md_abi_variant_hook(aux_info); 458 459 fd = -1; 460 if (aux_info[AT_EXECFD] != NULL) { 461 fd = aux_info[AT_EXECFD]->a_un.a_val; 462 } else { 463 assert(aux_info[AT_PHDR] != NULL); 464 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 465 if (phdr == obj_rtld.phdr) { 466 if (!trust) { 467 _rtld_error("Tainted process refusing to run binary %s", 468 argv0); 469 rtld_die(); 470 } 471 direct_exec = true; 472 473 /* 474 * Set osrel for us, it is later reset to the binary' 475 * value before first instruction of code from the binary 476 * is executed. 477 */ 478 mib[0] = CTL_KERN; 479 mib[1] = KERN_PROC; 480 mib[2] = KERN_PROC_OSREL; 481 mib[3] = getpid(); 482 osrel = __FreeBSD_version; 483 sz = sizeof(old_osrel); 484 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 485 486 dbg("opening main program in direct exec mode"); 487 if (argc >= 2) { 488 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0); 489 explicit_fd = (fd != -1); 490 binpath = NULL; 491 if (!explicit_fd) 492 fd = open_binary_fd(argv0, search_in_path, &binpath); 493 if (fstat(fd, &st) == -1) { 494 _rtld_error("Failed to fstat FD %d (%s): %s", fd, 495 explicit_fd ? "user-provided descriptor" : argv0, 496 rtld_strerror(errno)); 497 rtld_die(); 498 } 499 500 /* 501 * Rough emulation of the permission checks done by 502 * execve(2), only Unix DACs are checked, ACLs are 503 * ignored. Preserve the semantic of disabling owner 504 * to execute if owner x bit is cleared, even if 505 * others x bit is enabled. 506 * mmap(2) does not allow to mmap with PROT_EXEC if 507 * binary' file comes from noexec mount. We cannot 508 * set a text reference on the binary. 509 */ 510 dir_enable = false; 511 if (st.st_uid == geteuid()) { 512 if ((st.st_mode & S_IXUSR) != 0) 513 dir_enable = true; 514 } else if (st.st_gid == getegid()) { 515 if ((st.st_mode & S_IXGRP) != 0) 516 dir_enable = true; 517 } else if ((st.st_mode & S_IXOTH) != 0) { 518 dir_enable = true; 519 } 520 if (!dir_enable) { 521 _rtld_error("No execute permission for binary %s", 522 argv0); 523 rtld_die(); 524 } 525 526 /* 527 * For direct exec mode, argv[0] is the interpreter 528 * name, we must remove it and shift arguments left 529 * before invoking binary main. Since stack layout 530 * places environment pointers and aux vectors right 531 * after the terminating NULL, we must shift 532 * environment and aux as well. 533 */ 534 main_argc = argc - rtld_argc; 535 for (i = 0; i <= main_argc; i++) 536 argv[i] = argv[i + rtld_argc]; 537 *argcp -= rtld_argc; 538 environ = env = envp = argv + main_argc + 1; 539 dbg("move env from %p to %p", envp + rtld_argc, envp); 540 do { 541 *envp = *(envp + rtld_argc); 542 } while (*envp++ != NULL); 543 aux = auxp = (Elf_Auxinfo *)envp; 544 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 545 dbg("move aux from %p to %p", auxpf, aux); 546 /* XXXKIB insert place for AT_EXECPATH if not present */ 547 for (;; auxp++, auxpf++) { 548 *auxp = *auxpf; 549 if (auxp->a_type == AT_NULL) 550 break; 551 } 552 /* Since the auxiliary vector has moved, redigest it. */ 553 for (i = 0; i < AT_COUNT; i++) 554 aux_info[i] = NULL; 555 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 556 if (auxp->a_type < AT_COUNT) 557 aux_info[auxp->a_type] = auxp; 558 } 559 560 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 561 if (binpath == NULL) { 562 aux_info[AT_EXECPATH] = NULL; 563 } else { 564 if (aux_info[AT_EXECPATH] == NULL) { 565 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 566 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 567 } 568 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 569 binpath); 570 } 571 } else { 572 _rtld_error("No binary"); 573 rtld_die(); 574 } 575 } 576 } 577 578 ld_bind_now = getenv(_LD("BIND_NOW")); 579 580 /* 581 * If the process is tainted, then we un-set the dangerous environment 582 * variables. The process will be marked as tainted until setuid(2) 583 * is called. If any child process calls setuid(2) we do not want any 584 * future processes to honor the potentially un-safe variables. 585 */ 586 if (!trust) { 587 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 588 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 589 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 590 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 591 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 592 _rtld_error("environment corrupt; aborting"); 593 rtld_die(); 594 } 595 } 596 ld_debug = getenv(_LD("DEBUG")); 597 if (ld_bind_now == NULL) 598 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 599 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 600 libmap_override = getenv(_LD("LIBMAP")); 601 ld_library_path = getenv(_LD("LIBRARY_PATH")); 602 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 603 ld_preload = getenv(_LD("PRELOAD")); 604 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 605 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 606 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 607 if (library_path_rpath != NULL) { 608 if (library_path_rpath[0] == 'y' || 609 library_path_rpath[0] == 'Y' || 610 library_path_rpath[0] == '1') 611 ld_library_path_rpath = true; 612 else 613 ld_library_path_rpath = false; 614 } 615 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 616 (ld_library_path != NULL) || (ld_preload != NULL) || 617 (ld_elf_hints_path != NULL) || ld_loadfltr; 618 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 619 ld_utrace = getenv(_LD("UTRACE")); 620 621 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 622 ld_elf_hints_path = ld_elf_hints_default; 623 624 if (ld_debug != NULL && *ld_debug != '\0') 625 debug = 1; 626 dbg("%s is initialized, base address = %p", __progname, 627 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 628 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 629 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 630 631 dbg("initializing thread locks"); 632 lockdflt_init(); 633 634 /* 635 * Load the main program, or process its program header if it is 636 * already loaded. 637 */ 638 if (fd != -1) { /* Load the main program. */ 639 dbg("loading main program"); 640 obj_main = map_object(fd, argv0, NULL); 641 close(fd); 642 if (obj_main == NULL) 643 rtld_die(); 644 max_stack_flags = obj_main->stack_flags; 645 } else { /* Main program already loaded. */ 646 dbg("processing main program's program header"); 647 assert(aux_info[AT_PHDR] != NULL); 648 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 649 assert(aux_info[AT_PHNUM] != NULL); 650 phnum = aux_info[AT_PHNUM]->a_un.a_val; 651 assert(aux_info[AT_PHENT] != NULL); 652 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 653 assert(aux_info[AT_ENTRY] != NULL); 654 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 655 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 656 rtld_die(); 657 } 658 659 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 660 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 661 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 662 if (kexecpath[0] == '/') 663 obj_main->path = kexecpath; 664 else if (getcwd(buf, sizeof(buf)) == NULL || 665 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 666 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 667 obj_main->path = xstrdup(argv0); 668 else 669 obj_main->path = xstrdup(buf); 670 } else { 671 dbg("No AT_EXECPATH or direct exec"); 672 obj_main->path = xstrdup(argv0); 673 } 674 dbg("obj_main path %s", obj_main->path); 675 obj_main->mainprog = true; 676 677 if (aux_info[AT_STACKPROT] != NULL && 678 aux_info[AT_STACKPROT]->a_un.a_val != 0) 679 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 680 681 #ifndef COMPAT_32BIT 682 /* 683 * Get the actual dynamic linker pathname from the executable if 684 * possible. (It should always be possible.) That ensures that 685 * gdb will find the right dynamic linker even if a non-standard 686 * one is being used. 687 */ 688 if (obj_main->interp != NULL && 689 strcmp(obj_main->interp, obj_rtld.path) != 0) { 690 free(obj_rtld.path); 691 obj_rtld.path = xstrdup(obj_main->interp); 692 __progname = obj_rtld.path; 693 } 694 #endif 695 696 if (!digest_dynamic(obj_main, 0)) 697 rtld_die(); 698 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 699 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 700 obj_main->dynsymcount); 701 702 linkmap_add(obj_main); 703 linkmap_add(&obj_rtld); 704 705 /* Link the main program into the list of objects. */ 706 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 707 obj_count++; 708 obj_loads++; 709 710 /* Initialize a fake symbol for resolving undefined weak references. */ 711 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 712 sym_zero.st_shndx = SHN_UNDEF; 713 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 714 715 if (!libmap_disable) 716 libmap_disable = (bool)lm_init(libmap_override); 717 718 dbg("loading LD_PRELOAD libraries"); 719 if (load_preload_objects() == -1) 720 rtld_die(); 721 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 722 723 dbg("loading needed objects"); 724 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 725 0) == -1) 726 rtld_die(); 727 728 /* Make a list of all objects loaded at startup. */ 729 last_interposer = obj_main; 730 TAILQ_FOREACH(obj, &obj_list, next) { 731 if (obj->marker) 732 continue; 733 if (obj->z_interpose && obj != obj_main) { 734 objlist_put_after(&list_main, last_interposer, obj); 735 last_interposer = obj; 736 } else { 737 objlist_push_tail(&list_main, obj); 738 } 739 obj->refcount++; 740 } 741 742 dbg("checking for required versions"); 743 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 744 rtld_die(); 745 746 if (ld_tracing) { /* We're done */ 747 trace_loaded_objects(obj_main); 748 exit(0); 749 } 750 751 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 752 dump_relocations(obj_main); 753 exit (0); 754 } 755 756 /* 757 * Processing tls relocations requires having the tls offsets 758 * initialized. Prepare offsets before starting initial 759 * relocation processing. 760 */ 761 dbg("initializing initial thread local storage offsets"); 762 STAILQ_FOREACH(entry, &list_main, link) { 763 /* 764 * Allocate all the initial objects out of the static TLS 765 * block even if they didn't ask for it. 766 */ 767 allocate_tls_offset(entry->obj); 768 } 769 770 if (relocate_objects(obj_main, 771 ld_bind_now != NULL && *ld_bind_now != '\0', 772 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 773 rtld_die(); 774 775 dbg("doing copy relocations"); 776 if (do_copy_relocations(obj_main) == -1) 777 rtld_die(); 778 779 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 780 dump_relocations(obj_main); 781 exit (0); 782 } 783 784 ifunc_init(aux); 785 786 /* 787 * Setup TLS for main thread. This must be done after the 788 * relocations are processed, since tls initialization section 789 * might be the subject for relocations. 790 */ 791 dbg("initializing initial thread local storage"); 792 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 793 794 dbg("initializing key program variables"); 795 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 796 set_program_var("environ", env); 797 set_program_var("__elf_aux_vector", aux); 798 799 /* Make a list of init functions to call. */ 800 objlist_init(&initlist); 801 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 802 preload_tail, &initlist); 803 804 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 805 806 map_stacks_exec(NULL); 807 808 if (!obj_main->crt_no_init) { 809 /* 810 * Make sure we don't call the main program's init and fini 811 * functions for binaries linked with old crt1 which calls 812 * _init itself. 813 */ 814 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 815 obj_main->preinit_array = obj_main->init_array = 816 obj_main->fini_array = (Elf_Addr)NULL; 817 } 818 819 /* 820 * Execute MD initializers required before we call the objects' 821 * init functions. 822 */ 823 pre_init(); 824 825 if (direct_exec) { 826 /* Set osrel for direct-execed binary */ 827 mib[0] = CTL_KERN; 828 mib[1] = KERN_PROC; 829 mib[2] = KERN_PROC_OSREL; 830 mib[3] = getpid(); 831 osrel = obj_main->osrel; 832 sz = sizeof(old_osrel); 833 dbg("setting osrel to %d", osrel); 834 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); 835 } 836 837 wlock_acquire(rtld_bind_lock, &lockstate); 838 839 dbg("resolving ifuncs"); 840 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 841 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 842 rtld_die(); 843 844 rtld_exit_ptr = rtld_exit; 845 if (obj_main->crt_no_init) 846 preinit_main(); 847 objlist_call_init(&initlist, &lockstate); 848 _r_debug_postinit(&obj_main->linkmap); 849 objlist_clear(&initlist); 850 dbg("loading filtees"); 851 TAILQ_FOREACH(obj, &obj_list, next) { 852 if (obj->marker) 853 continue; 854 if (ld_loadfltr || obj->z_loadfltr) 855 load_filtees(obj, 0, &lockstate); 856 } 857 858 dbg("enforcing main obj relro"); 859 if (obj_enforce_relro(obj_main) == -1) 860 rtld_die(); 861 862 lock_release(rtld_bind_lock, &lockstate); 863 864 dbg("transferring control to program entry point = %p", obj_main->entry); 865 866 /* Return the exit procedure and the program entry point. */ 867 *exit_proc = rtld_exit_ptr; 868 *objp = obj_main; 869 return (func_ptr_type) obj_main->entry; 870 } 871 872 void * 873 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 874 { 875 void *ptr; 876 Elf_Addr target; 877 878 ptr = (void *)make_function_pointer(def, obj); 879 target = call_ifunc_resolver(ptr); 880 return ((void *)target); 881 } 882 883 /* 884 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 885 * Changes to this function should be applied there as well. 886 */ 887 Elf_Addr 888 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 889 { 890 const Elf_Rel *rel; 891 const Elf_Sym *def; 892 const Obj_Entry *defobj; 893 Elf_Addr *where; 894 Elf_Addr target; 895 RtldLockState lockstate; 896 897 rlock_acquire(rtld_bind_lock, &lockstate); 898 if (sigsetjmp(lockstate.env, 0) != 0) 899 lock_upgrade(rtld_bind_lock, &lockstate); 900 if (obj->pltrel) 901 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); 902 else 903 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); 904 905 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 906 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 907 NULL, &lockstate); 908 if (def == NULL) 909 rtld_die(); 910 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 911 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 912 else 913 target = (Elf_Addr)(defobj->relocbase + def->st_value); 914 915 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 916 defobj->strtab + def->st_name, basename(obj->path), 917 (void *)target, basename(defobj->path)); 918 919 /* 920 * Write the new contents for the jmpslot. Note that depending on 921 * architecture, the value which we need to return back to the 922 * lazy binding trampoline may or may not be the target 923 * address. The value returned from reloc_jmpslot() is the value 924 * that the trampoline needs. 925 */ 926 target = reloc_jmpslot(where, target, defobj, obj, rel); 927 lock_release(rtld_bind_lock, &lockstate); 928 return target; 929 } 930 931 /* 932 * Error reporting function. Use it like printf. If formats the message 933 * into a buffer, and sets things up so that the next call to dlerror() 934 * will return the message. 935 */ 936 void 937 _rtld_error(const char *fmt, ...) 938 { 939 static char buf[512]; 940 va_list ap; 941 942 va_start(ap, fmt); 943 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 944 error_message = buf; 945 va_end(ap); 946 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message); 947 } 948 949 /* 950 * Return a dynamically-allocated copy of the current error message, if any. 951 */ 952 static char * 953 errmsg_save(void) 954 { 955 return error_message == NULL ? NULL : xstrdup(error_message); 956 } 957 958 /* 959 * Restore the current error message from a copy which was previously saved 960 * by errmsg_save(). The copy is freed. 961 */ 962 static void 963 errmsg_restore(char *saved_msg) 964 { 965 if (saved_msg == NULL) 966 error_message = NULL; 967 else { 968 _rtld_error("%s", saved_msg); 969 free(saved_msg); 970 } 971 } 972 973 static const char * 974 basename(const char *name) 975 { 976 const char *p = strrchr(name, '/'); 977 return p != NULL ? p + 1 : name; 978 } 979 980 static struct utsname uts; 981 982 static char * 983 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 984 const char *subst, bool may_free) 985 { 986 char *p, *p1, *res, *resp; 987 int subst_len, kw_len, subst_count, old_len, new_len; 988 989 kw_len = strlen(kw); 990 991 /* 992 * First, count the number of the keyword occurrences, to 993 * preallocate the final string. 994 */ 995 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 996 p1 = strstr(p, kw); 997 if (p1 == NULL) 998 break; 999 } 1000 1001 /* 1002 * If the keyword is not found, just return. 1003 * 1004 * Return non-substituted string if resolution failed. We 1005 * cannot do anything more reasonable, the failure mode of the 1006 * caller is unresolved library anyway. 1007 */ 1008 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 1009 return (may_free ? real : xstrdup(real)); 1010 if (obj != NULL) 1011 subst = obj->origin_path; 1012 1013 /* 1014 * There is indeed something to substitute. Calculate the 1015 * length of the resulting string, and allocate it. 1016 */ 1017 subst_len = strlen(subst); 1018 old_len = strlen(real); 1019 new_len = old_len + (subst_len - kw_len) * subst_count; 1020 res = xmalloc(new_len + 1); 1021 1022 /* 1023 * Now, execute the substitution loop. 1024 */ 1025 for (p = real, resp = res, *resp = '\0';;) { 1026 p1 = strstr(p, kw); 1027 if (p1 != NULL) { 1028 /* Copy the prefix before keyword. */ 1029 memcpy(resp, p, p1 - p); 1030 resp += p1 - p; 1031 /* Keyword replacement. */ 1032 memcpy(resp, subst, subst_len); 1033 resp += subst_len; 1034 *resp = '\0'; 1035 p = p1 + kw_len; 1036 } else 1037 break; 1038 } 1039 1040 /* Copy to the end of string and finish. */ 1041 strcat(resp, p); 1042 if (may_free) 1043 free(real); 1044 return (res); 1045 } 1046 1047 static char * 1048 origin_subst(Obj_Entry *obj, const char *real) 1049 { 1050 char *res1, *res2, *res3, *res4; 1051 1052 if (obj == NULL || !trust) 1053 return (xstrdup(real)); 1054 if (uts.sysname[0] == '\0') { 1055 if (uname(&uts) != 0) { 1056 _rtld_error("utsname failed: %d", errno); 1057 return (NULL); 1058 } 1059 } 1060 /* __DECONST is safe here since without may_free real is unchanged */ 1061 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL, 1062 false); 1063 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1064 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1065 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1066 return (res4); 1067 } 1068 1069 void 1070 rtld_die(void) 1071 { 1072 const char *msg = dlerror(); 1073 1074 if (msg == NULL) 1075 msg = "Fatal error"; 1076 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); 1077 rtld_fdputstr(STDERR_FILENO, msg); 1078 rtld_fdputchar(STDERR_FILENO, '\n'); 1079 _exit(1); 1080 } 1081 1082 /* 1083 * Process a shared object's DYNAMIC section, and save the important 1084 * information in its Obj_Entry structure. 1085 */ 1086 static void 1087 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1088 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1089 { 1090 const Elf_Dyn *dynp; 1091 Needed_Entry **needed_tail = &obj->needed; 1092 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1093 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1094 const Elf_Hashelt *hashtab; 1095 const Elf32_Word *hashval; 1096 Elf32_Word bkt, nmaskwords; 1097 int bloom_size32; 1098 int plttype = DT_REL; 1099 1100 *dyn_rpath = NULL; 1101 *dyn_soname = NULL; 1102 *dyn_runpath = NULL; 1103 1104 obj->bind_now = false; 1105 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1106 switch (dynp->d_tag) { 1107 1108 case DT_REL: 1109 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); 1110 break; 1111 1112 case DT_RELSZ: 1113 obj->relsize = dynp->d_un.d_val; 1114 break; 1115 1116 case DT_RELENT: 1117 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1118 break; 1119 1120 case DT_JMPREL: 1121 obj->pltrel = (const Elf_Rel *) 1122 (obj->relocbase + dynp->d_un.d_ptr); 1123 break; 1124 1125 case DT_PLTRELSZ: 1126 obj->pltrelsize = dynp->d_un.d_val; 1127 break; 1128 1129 case DT_RELA: 1130 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); 1131 break; 1132 1133 case DT_RELASZ: 1134 obj->relasize = dynp->d_un.d_val; 1135 break; 1136 1137 case DT_RELAENT: 1138 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1139 break; 1140 1141 case DT_PLTREL: 1142 plttype = dynp->d_un.d_val; 1143 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1144 break; 1145 1146 case DT_SYMTAB: 1147 obj->symtab = (const Elf_Sym *) 1148 (obj->relocbase + dynp->d_un.d_ptr); 1149 break; 1150 1151 case DT_SYMENT: 1152 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1153 break; 1154 1155 case DT_STRTAB: 1156 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); 1157 break; 1158 1159 case DT_STRSZ: 1160 obj->strsize = dynp->d_un.d_val; 1161 break; 1162 1163 case DT_VERNEED: 1164 obj->verneed = (const Elf_Verneed *)(obj->relocbase + 1165 dynp->d_un.d_val); 1166 break; 1167 1168 case DT_VERNEEDNUM: 1169 obj->verneednum = dynp->d_un.d_val; 1170 break; 1171 1172 case DT_VERDEF: 1173 obj->verdef = (const Elf_Verdef *)(obj->relocbase + 1174 dynp->d_un.d_val); 1175 break; 1176 1177 case DT_VERDEFNUM: 1178 obj->verdefnum = dynp->d_un.d_val; 1179 break; 1180 1181 case DT_VERSYM: 1182 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1183 dynp->d_un.d_val); 1184 break; 1185 1186 case DT_HASH: 1187 { 1188 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1189 dynp->d_un.d_ptr); 1190 obj->nbuckets = hashtab[0]; 1191 obj->nchains = hashtab[1]; 1192 obj->buckets = hashtab + 2; 1193 obj->chains = obj->buckets + obj->nbuckets; 1194 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1195 obj->buckets != NULL; 1196 } 1197 break; 1198 1199 case DT_GNU_HASH: 1200 { 1201 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1202 dynp->d_un.d_ptr); 1203 obj->nbuckets_gnu = hashtab[0]; 1204 obj->symndx_gnu = hashtab[1]; 1205 nmaskwords = hashtab[2]; 1206 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1207 obj->maskwords_bm_gnu = nmaskwords - 1; 1208 obj->shift2_gnu = hashtab[3]; 1209 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); 1210 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1211 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1212 obj->symndx_gnu; 1213 /* Number of bitmask words is required to be power of 2 */ 1214 obj->valid_hash_gnu = powerof2(nmaskwords) && 1215 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1216 } 1217 break; 1218 1219 case DT_NEEDED: 1220 if (!obj->rtld) { 1221 Needed_Entry *nep = NEW(Needed_Entry); 1222 nep->name = dynp->d_un.d_val; 1223 nep->obj = NULL; 1224 nep->next = NULL; 1225 1226 *needed_tail = nep; 1227 needed_tail = &nep->next; 1228 } 1229 break; 1230 1231 case DT_FILTER: 1232 if (!obj->rtld) { 1233 Needed_Entry *nep = NEW(Needed_Entry); 1234 nep->name = dynp->d_un.d_val; 1235 nep->obj = NULL; 1236 nep->next = NULL; 1237 1238 *needed_filtees_tail = nep; 1239 needed_filtees_tail = &nep->next; 1240 1241 if (obj->linkmap.l_refname == NULL) 1242 obj->linkmap.l_refname = (char *)dynp->d_un.d_val; 1243 } 1244 break; 1245 1246 case DT_AUXILIARY: 1247 if (!obj->rtld) { 1248 Needed_Entry *nep = NEW(Needed_Entry); 1249 nep->name = dynp->d_un.d_val; 1250 nep->obj = NULL; 1251 nep->next = NULL; 1252 1253 *needed_aux_filtees_tail = nep; 1254 needed_aux_filtees_tail = &nep->next; 1255 } 1256 break; 1257 1258 case DT_PLTGOT: 1259 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1260 break; 1261 1262 case DT_TEXTREL: 1263 obj->textrel = true; 1264 break; 1265 1266 case DT_SYMBOLIC: 1267 obj->symbolic = true; 1268 break; 1269 1270 case DT_RPATH: 1271 /* 1272 * We have to wait until later to process this, because we 1273 * might not have gotten the address of the string table yet. 1274 */ 1275 *dyn_rpath = dynp; 1276 break; 1277 1278 case DT_SONAME: 1279 *dyn_soname = dynp; 1280 break; 1281 1282 case DT_RUNPATH: 1283 *dyn_runpath = dynp; 1284 break; 1285 1286 case DT_INIT: 1287 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1288 break; 1289 1290 case DT_PREINIT_ARRAY: 1291 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1292 break; 1293 1294 case DT_PREINIT_ARRAYSZ: 1295 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1296 break; 1297 1298 case DT_INIT_ARRAY: 1299 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1300 break; 1301 1302 case DT_INIT_ARRAYSZ: 1303 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1304 break; 1305 1306 case DT_FINI: 1307 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1308 break; 1309 1310 case DT_FINI_ARRAY: 1311 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1312 break; 1313 1314 case DT_FINI_ARRAYSZ: 1315 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1316 break; 1317 1318 /* 1319 * Don't process DT_DEBUG on MIPS as the dynamic section 1320 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1321 */ 1322 1323 #ifndef __mips__ 1324 case DT_DEBUG: 1325 if (!early) 1326 dbg("Filling in DT_DEBUG entry"); 1327 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; 1328 break; 1329 #endif 1330 1331 case DT_FLAGS: 1332 if (dynp->d_un.d_val & DF_ORIGIN) 1333 obj->z_origin = true; 1334 if (dynp->d_un.d_val & DF_SYMBOLIC) 1335 obj->symbolic = true; 1336 if (dynp->d_un.d_val & DF_TEXTREL) 1337 obj->textrel = true; 1338 if (dynp->d_un.d_val & DF_BIND_NOW) 1339 obj->bind_now = true; 1340 if (dynp->d_un.d_val & DF_STATIC_TLS) 1341 obj->static_tls = true; 1342 break; 1343 #ifdef __mips__ 1344 case DT_MIPS_LOCAL_GOTNO: 1345 obj->local_gotno = dynp->d_un.d_val; 1346 break; 1347 1348 case DT_MIPS_SYMTABNO: 1349 obj->symtabno = dynp->d_un.d_val; 1350 break; 1351 1352 case DT_MIPS_GOTSYM: 1353 obj->gotsym = dynp->d_un.d_val; 1354 break; 1355 1356 case DT_MIPS_RLD_MAP: 1357 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1358 break; 1359 1360 case DT_MIPS_RLD_MAP_REL: 1361 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map 1362 // section relative to the address of the tag itself. 1363 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) = 1364 (Elf_Addr) &r_debug; 1365 break; 1366 1367 case DT_MIPS_PLTGOT: 1368 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase + 1369 dynp->d_un.d_ptr); 1370 break; 1371 1372 #endif 1373 1374 #ifdef __powerpc__ 1375 #ifdef __powerpc64__ 1376 case DT_PPC64_GLINK: 1377 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1378 break; 1379 #else 1380 case DT_PPC_GOT: 1381 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); 1382 break; 1383 #endif 1384 #endif 1385 1386 case DT_FLAGS_1: 1387 if (dynp->d_un.d_val & DF_1_NOOPEN) 1388 obj->z_noopen = true; 1389 if (dynp->d_un.d_val & DF_1_ORIGIN) 1390 obj->z_origin = true; 1391 if (dynp->d_un.d_val & DF_1_GLOBAL) 1392 obj->z_global = true; 1393 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1394 obj->bind_now = true; 1395 if (dynp->d_un.d_val & DF_1_NODELETE) 1396 obj->z_nodelete = true; 1397 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1398 obj->z_loadfltr = true; 1399 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1400 obj->z_interpose = true; 1401 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1402 obj->z_nodeflib = true; 1403 if (dynp->d_un.d_val & DF_1_PIE) 1404 obj->z_pie = true; 1405 break; 1406 1407 default: 1408 if (!early) { 1409 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1410 (long)dynp->d_tag); 1411 } 1412 break; 1413 } 1414 } 1415 1416 obj->traced = false; 1417 1418 if (plttype == DT_RELA) { 1419 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1420 obj->pltrel = NULL; 1421 obj->pltrelasize = obj->pltrelsize; 1422 obj->pltrelsize = 0; 1423 } 1424 1425 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1426 if (obj->valid_hash_sysv) 1427 obj->dynsymcount = obj->nchains; 1428 else if (obj->valid_hash_gnu) { 1429 obj->dynsymcount = 0; 1430 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1431 if (obj->buckets_gnu[bkt] == 0) 1432 continue; 1433 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1434 do 1435 obj->dynsymcount++; 1436 while ((*hashval++ & 1u) == 0); 1437 } 1438 obj->dynsymcount += obj->symndx_gnu; 1439 } 1440 1441 if (obj->linkmap.l_refname != NULL) 1442 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj-> 1443 linkmap.l_refname; 1444 } 1445 1446 static bool 1447 obj_resolve_origin(Obj_Entry *obj) 1448 { 1449 1450 if (obj->origin_path != NULL) 1451 return (true); 1452 obj->origin_path = xmalloc(PATH_MAX); 1453 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1454 } 1455 1456 static bool 1457 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1458 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1459 { 1460 1461 if (obj->z_origin && !obj_resolve_origin(obj)) 1462 return (false); 1463 1464 if (dyn_runpath != NULL) { 1465 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; 1466 obj->runpath = origin_subst(obj, obj->runpath); 1467 } else if (dyn_rpath != NULL) { 1468 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; 1469 obj->rpath = origin_subst(obj, obj->rpath); 1470 } 1471 if (dyn_soname != NULL) 1472 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1473 return (true); 1474 } 1475 1476 static bool 1477 digest_dynamic(Obj_Entry *obj, int early) 1478 { 1479 const Elf_Dyn *dyn_rpath; 1480 const Elf_Dyn *dyn_soname; 1481 const Elf_Dyn *dyn_runpath; 1482 1483 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1484 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1485 } 1486 1487 /* 1488 * Process a shared object's program header. This is used only for the 1489 * main program, when the kernel has already loaded the main program 1490 * into memory before calling the dynamic linker. It creates and 1491 * returns an Obj_Entry structure. 1492 */ 1493 static Obj_Entry * 1494 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1495 { 1496 Obj_Entry *obj; 1497 const Elf_Phdr *phlimit = phdr + phnum; 1498 const Elf_Phdr *ph; 1499 Elf_Addr note_start, note_end; 1500 int nsegs = 0; 1501 1502 obj = obj_new(); 1503 for (ph = phdr; ph < phlimit; ph++) { 1504 if (ph->p_type != PT_PHDR) 1505 continue; 1506 1507 obj->phdr = phdr; 1508 obj->phsize = ph->p_memsz; 1509 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; 1510 break; 1511 } 1512 1513 obj->stack_flags = PF_X | PF_R | PF_W; 1514 1515 for (ph = phdr; ph < phlimit; ph++) { 1516 switch (ph->p_type) { 1517 1518 case PT_INTERP: 1519 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1520 break; 1521 1522 case PT_LOAD: 1523 if (nsegs == 0) { /* First load segment */ 1524 obj->vaddrbase = trunc_page(ph->p_vaddr); 1525 obj->mapbase = obj->vaddrbase + obj->relocbase; 1526 } else { /* Last load segment */ 1527 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1528 obj->vaddrbase; 1529 } 1530 nsegs++; 1531 break; 1532 1533 case PT_DYNAMIC: 1534 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1535 break; 1536 1537 case PT_TLS: 1538 obj->tlsindex = 1; 1539 obj->tlssize = ph->p_memsz; 1540 obj->tlsalign = ph->p_align; 1541 obj->tlsinitsize = ph->p_filesz; 1542 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1543 obj->tlspoffset = ph->p_offset; 1544 break; 1545 1546 case PT_GNU_STACK: 1547 obj->stack_flags = ph->p_flags; 1548 break; 1549 1550 case PT_GNU_RELRO: 1551 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1552 obj->relro_size = round_page(ph->p_memsz); 1553 break; 1554 1555 case PT_NOTE: 1556 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1557 note_end = note_start + ph->p_filesz; 1558 digest_notes(obj, note_start, note_end); 1559 break; 1560 } 1561 } 1562 if (nsegs < 1) { 1563 _rtld_error("%s: too few PT_LOAD segments", path); 1564 return NULL; 1565 } 1566 1567 obj->entry = entry; 1568 return obj; 1569 } 1570 1571 void 1572 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1573 { 1574 const Elf_Note *note; 1575 const char *note_name; 1576 uintptr_t p; 1577 1578 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1579 note = (const Elf_Note *)((const char *)(note + 1) + 1580 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1581 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1582 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1583 note->n_descsz != sizeof(int32_t)) 1584 continue; 1585 if (note->n_type != NT_FREEBSD_ABI_TAG && 1586 note->n_type != NT_FREEBSD_FEATURE_CTL && 1587 note->n_type != NT_FREEBSD_NOINIT_TAG) 1588 continue; 1589 note_name = (const char *)(note + 1); 1590 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1591 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1592 continue; 1593 switch (note->n_type) { 1594 case NT_FREEBSD_ABI_TAG: 1595 /* FreeBSD osrel note */ 1596 p = (uintptr_t)(note + 1); 1597 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1598 obj->osrel = *(const int32_t *)(p); 1599 dbg("note osrel %d", obj->osrel); 1600 break; 1601 case NT_FREEBSD_FEATURE_CTL: 1602 /* FreeBSD ABI feature control note */ 1603 p = (uintptr_t)(note + 1); 1604 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1605 obj->fctl0 = *(const uint32_t *)(p); 1606 dbg("note fctl0 %#x", obj->fctl0); 1607 break; 1608 case NT_FREEBSD_NOINIT_TAG: 1609 /* FreeBSD 'crt does not call init' note */ 1610 obj->crt_no_init = true; 1611 dbg("note crt_no_init"); 1612 break; 1613 } 1614 } 1615 } 1616 1617 static Obj_Entry * 1618 dlcheck(void *handle) 1619 { 1620 Obj_Entry *obj; 1621 1622 TAILQ_FOREACH(obj, &obj_list, next) { 1623 if (obj == (Obj_Entry *) handle) 1624 break; 1625 } 1626 1627 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1628 _rtld_error("Invalid shared object handle %p", handle); 1629 return NULL; 1630 } 1631 return obj; 1632 } 1633 1634 /* 1635 * If the given object is already in the donelist, return true. Otherwise 1636 * add the object to the list and return false. 1637 */ 1638 static bool 1639 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1640 { 1641 unsigned int i; 1642 1643 for (i = 0; i < dlp->num_used; i++) 1644 if (dlp->objs[i] == obj) 1645 return true; 1646 /* 1647 * Our donelist allocation should always be sufficient. But if 1648 * our threads locking isn't working properly, more shared objects 1649 * could have been loaded since we allocated the list. That should 1650 * never happen, but we'll handle it properly just in case it does. 1651 */ 1652 if (dlp->num_used < dlp->num_alloc) 1653 dlp->objs[dlp->num_used++] = obj; 1654 return false; 1655 } 1656 1657 /* 1658 * Hash function for symbol table lookup. Don't even think about changing 1659 * this. It is specified by the System V ABI. 1660 */ 1661 unsigned long 1662 elf_hash(const char *name) 1663 { 1664 const unsigned char *p = (const unsigned char *) name; 1665 unsigned long h = 0; 1666 unsigned long g; 1667 1668 while (*p != '\0') { 1669 h = (h << 4) + *p++; 1670 if ((g = h & 0xf0000000) != 0) 1671 h ^= g >> 24; 1672 h &= ~g; 1673 } 1674 return h; 1675 } 1676 1677 /* 1678 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1679 * unsigned in case it's implemented with a wider type. 1680 */ 1681 static uint32_t 1682 gnu_hash(const char *s) 1683 { 1684 uint32_t h; 1685 unsigned char c; 1686 1687 h = 5381; 1688 for (c = *s; c != '\0'; c = *++s) 1689 h = h * 33 + c; 1690 return (h & 0xffffffff); 1691 } 1692 1693 1694 /* 1695 * Find the library with the given name, and return its full pathname. 1696 * The returned string is dynamically allocated. Generates an error 1697 * message and returns NULL if the library cannot be found. 1698 * 1699 * If the second argument is non-NULL, then it refers to an already- 1700 * loaded shared object, whose library search path will be searched. 1701 * 1702 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1703 * descriptor (which is close-on-exec) will be passed out via the third 1704 * argument. 1705 * 1706 * The search order is: 1707 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1708 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1709 * LD_LIBRARY_PATH 1710 * DT_RUNPATH in the referencing file 1711 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1712 * from list) 1713 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1714 * 1715 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1716 */ 1717 static char * 1718 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1719 { 1720 char *pathname, *refobj_path; 1721 const char *name; 1722 bool nodeflib, objgiven; 1723 1724 objgiven = refobj != NULL; 1725 1726 if (libmap_disable || !objgiven || 1727 (name = lm_find(refobj->path, xname)) == NULL) 1728 name = xname; 1729 1730 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1731 if (name[0] != '/' && !trust) { 1732 _rtld_error("Absolute pathname required " 1733 "for shared object \"%s\"", name); 1734 return (NULL); 1735 } 1736 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1737 __DECONST(char *, name))); 1738 } 1739 1740 dbg(" Searching for \"%s\"", name); 1741 refobj_path = objgiven ? refobj->path : NULL; 1742 1743 /* 1744 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1745 * back to pre-conforming behaviour if user requested so with 1746 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1747 * nodeflib. 1748 */ 1749 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1750 pathname = search_library_path(name, ld_library_path, 1751 refobj_path, fdp); 1752 if (pathname != NULL) 1753 return (pathname); 1754 if (refobj != NULL) { 1755 pathname = search_library_path(name, refobj->rpath, 1756 refobj_path, fdp); 1757 if (pathname != NULL) 1758 return (pathname); 1759 } 1760 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1761 if (pathname != NULL) 1762 return (pathname); 1763 pathname = search_library_path(name, gethints(false), 1764 refobj_path, fdp); 1765 if (pathname != NULL) 1766 return (pathname); 1767 pathname = search_library_path(name, ld_standard_library_path, 1768 refobj_path, fdp); 1769 if (pathname != NULL) 1770 return (pathname); 1771 } else { 1772 nodeflib = objgiven ? refobj->z_nodeflib : false; 1773 if (objgiven) { 1774 pathname = search_library_path(name, refobj->rpath, 1775 refobj->path, fdp); 1776 if (pathname != NULL) 1777 return (pathname); 1778 } 1779 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1780 pathname = search_library_path(name, obj_main->rpath, 1781 refobj_path, fdp); 1782 if (pathname != NULL) 1783 return (pathname); 1784 } 1785 pathname = search_library_path(name, ld_library_path, 1786 refobj_path, fdp); 1787 if (pathname != NULL) 1788 return (pathname); 1789 if (objgiven) { 1790 pathname = search_library_path(name, refobj->runpath, 1791 refobj_path, fdp); 1792 if (pathname != NULL) 1793 return (pathname); 1794 } 1795 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1796 if (pathname != NULL) 1797 return (pathname); 1798 pathname = search_library_path(name, gethints(nodeflib), 1799 refobj_path, fdp); 1800 if (pathname != NULL) 1801 return (pathname); 1802 if (objgiven && !nodeflib) { 1803 pathname = search_library_path(name, 1804 ld_standard_library_path, refobj_path, fdp); 1805 if (pathname != NULL) 1806 return (pathname); 1807 } 1808 } 1809 1810 if (objgiven && refobj->path != NULL) { 1811 _rtld_error("Shared object \"%s\" not found, " 1812 "required by \"%s\"", name, basename(refobj->path)); 1813 } else { 1814 _rtld_error("Shared object \"%s\" not found", name); 1815 } 1816 return (NULL); 1817 } 1818 1819 /* 1820 * Given a symbol number in a referencing object, find the corresponding 1821 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1822 * no definition was found. Returns a pointer to the Obj_Entry of the 1823 * defining object via the reference parameter DEFOBJ_OUT. 1824 */ 1825 const Elf_Sym * 1826 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1827 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1828 RtldLockState *lockstate) 1829 { 1830 const Elf_Sym *ref; 1831 const Elf_Sym *def; 1832 const Obj_Entry *defobj; 1833 const Ver_Entry *ve; 1834 SymLook req; 1835 const char *name; 1836 int res; 1837 1838 /* 1839 * If we have already found this symbol, get the information from 1840 * the cache. 1841 */ 1842 if (symnum >= refobj->dynsymcount) 1843 return NULL; /* Bad object */ 1844 if (cache != NULL && cache[symnum].sym != NULL) { 1845 *defobj_out = cache[symnum].obj; 1846 return cache[symnum].sym; 1847 } 1848 1849 ref = refobj->symtab + symnum; 1850 name = refobj->strtab + ref->st_name; 1851 def = NULL; 1852 defobj = NULL; 1853 ve = NULL; 1854 1855 /* 1856 * We don't have to do a full scale lookup if the symbol is local. 1857 * We know it will bind to the instance in this load module; to 1858 * which we already have a pointer (ie ref). By not doing a lookup, 1859 * we not only improve performance, but it also avoids unresolvable 1860 * symbols when local symbols are not in the hash table. This has 1861 * been seen with the ia64 toolchain. 1862 */ 1863 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1864 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1865 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1866 symnum); 1867 } 1868 symlook_init(&req, name); 1869 req.flags = flags; 1870 ve = req.ventry = fetch_ventry(refobj, symnum); 1871 req.lockstate = lockstate; 1872 res = symlook_default(&req, refobj); 1873 if (res == 0) { 1874 def = req.sym_out; 1875 defobj = req.defobj_out; 1876 } 1877 } else { 1878 def = ref; 1879 defobj = refobj; 1880 } 1881 1882 /* 1883 * If we found no definition and the reference is weak, treat the 1884 * symbol as having the value zero. 1885 */ 1886 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1887 def = &sym_zero; 1888 defobj = obj_main; 1889 } 1890 1891 if (def != NULL) { 1892 *defobj_out = defobj; 1893 /* Record the information in the cache to avoid subsequent lookups. */ 1894 if (cache != NULL) { 1895 cache[symnum].sym = def; 1896 cache[symnum].obj = defobj; 1897 } 1898 } else { 1899 if (refobj != &obj_rtld) 1900 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1901 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1902 } 1903 return def; 1904 } 1905 1906 /* 1907 * Return the search path from the ldconfig hints file, reading it if 1908 * necessary. If nostdlib is true, then the default search paths are 1909 * not added to result. 1910 * 1911 * Returns NULL if there are problems with the hints file, 1912 * or if the search path there is empty. 1913 */ 1914 static const char * 1915 gethints(bool nostdlib) 1916 { 1917 static char *filtered_path; 1918 static const char *hints; 1919 static struct elfhints_hdr hdr; 1920 struct fill_search_info_args sargs, hargs; 1921 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1922 struct dl_serpath *SLPpath, *hintpath; 1923 char *p; 1924 struct stat hint_stat; 1925 unsigned int SLPndx, hintndx, fndx, fcount; 1926 int fd; 1927 size_t flen; 1928 uint32_t dl; 1929 bool skip; 1930 1931 /* First call, read the hints file */ 1932 if (hints == NULL) { 1933 /* Keep from trying again in case the hints file is bad. */ 1934 hints = ""; 1935 1936 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1937 return (NULL); 1938 1939 /* 1940 * Check of hdr.dirlistlen value against type limit 1941 * intends to pacify static analyzers. Further 1942 * paranoia leads to checks that dirlist is fully 1943 * contained in the file range. 1944 */ 1945 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1946 hdr.magic != ELFHINTS_MAGIC || 1947 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1948 fstat(fd, &hint_stat) == -1) { 1949 cleanup1: 1950 close(fd); 1951 hdr.dirlistlen = 0; 1952 return (NULL); 1953 } 1954 dl = hdr.strtab; 1955 if (dl + hdr.dirlist < dl) 1956 goto cleanup1; 1957 dl += hdr.dirlist; 1958 if (dl + hdr.dirlistlen < dl) 1959 goto cleanup1; 1960 dl += hdr.dirlistlen; 1961 if (dl > hint_stat.st_size) 1962 goto cleanup1; 1963 p = xmalloc(hdr.dirlistlen + 1); 1964 if (pread(fd, p, hdr.dirlistlen + 1, 1965 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1966 p[hdr.dirlistlen] != '\0') { 1967 free(p); 1968 goto cleanup1; 1969 } 1970 hints = p; 1971 close(fd); 1972 } 1973 1974 /* 1975 * If caller agreed to receive list which includes the default 1976 * paths, we are done. Otherwise, if we still did not 1977 * calculated filtered result, do it now. 1978 */ 1979 if (!nostdlib) 1980 return (hints[0] != '\0' ? hints : NULL); 1981 if (filtered_path != NULL) 1982 goto filt_ret; 1983 1984 /* 1985 * Obtain the list of all configured search paths, and the 1986 * list of the default paths. 1987 * 1988 * First estimate the size of the results. 1989 */ 1990 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1991 smeta.dls_cnt = 0; 1992 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1993 hmeta.dls_cnt = 0; 1994 1995 sargs.request = RTLD_DI_SERINFOSIZE; 1996 sargs.serinfo = &smeta; 1997 hargs.request = RTLD_DI_SERINFOSIZE; 1998 hargs.serinfo = &hmeta; 1999 2000 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2001 &sargs); 2002 path_enumerate(hints, fill_search_info, NULL, &hargs); 2003 2004 SLPinfo = xmalloc(smeta.dls_size); 2005 hintinfo = xmalloc(hmeta.dls_size); 2006 2007 /* 2008 * Next fetch both sets of paths. 2009 */ 2010 sargs.request = RTLD_DI_SERINFO; 2011 sargs.serinfo = SLPinfo; 2012 sargs.serpath = &SLPinfo->dls_serpath[0]; 2013 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 2014 2015 hargs.request = RTLD_DI_SERINFO; 2016 hargs.serinfo = hintinfo; 2017 hargs.serpath = &hintinfo->dls_serpath[0]; 2018 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 2019 2020 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 2021 &sargs); 2022 path_enumerate(hints, fill_search_info, NULL, &hargs); 2023 2024 /* 2025 * Now calculate the difference between two sets, by excluding 2026 * standard paths from the full set. 2027 */ 2028 fndx = 0; 2029 fcount = 0; 2030 filtered_path = xmalloc(hdr.dirlistlen + 1); 2031 hintpath = &hintinfo->dls_serpath[0]; 2032 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 2033 skip = false; 2034 SLPpath = &SLPinfo->dls_serpath[0]; 2035 /* 2036 * Check each standard path against current. 2037 */ 2038 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 2039 /* matched, skip the path */ 2040 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 2041 skip = true; 2042 break; 2043 } 2044 } 2045 if (skip) 2046 continue; 2047 /* 2048 * Not matched against any standard path, add the path 2049 * to result. Separate consequtive paths with ':'. 2050 */ 2051 if (fcount > 0) { 2052 filtered_path[fndx] = ':'; 2053 fndx++; 2054 } 2055 fcount++; 2056 flen = strlen(hintpath->dls_name); 2057 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 2058 fndx += flen; 2059 } 2060 filtered_path[fndx] = '\0'; 2061 2062 free(SLPinfo); 2063 free(hintinfo); 2064 2065 filt_ret: 2066 return (filtered_path[0] != '\0' ? filtered_path : NULL); 2067 } 2068 2069 static void 2070 init_dag(Obj_Entry *root) 2071 { 2072 const Needed_Entry *needed; 2073 const Objlist_Entry *elm; 2074 DoneList donelist; 2075 2076 if (root->dag_inited) 2077 return; 2078 donelist_init(&donelist); 2079 2080 /* Root object belongs to own DAG. */ 2081 objlist_push_tail(&root->dldags, root); 2082 objlist_push_tail(&root->dagmembers, root); 2083 donelist_check(&donelist, root); 2084 2085 /* 2086 * Add dependencies of root object to DAG in breadth order 2087 * by exploiting the fact that each new object get added 2088 * to the tail of the dagmembers list. 2089 */ 2090 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2091 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 2092 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 2093 continue; 2094 objlist_push_tail(&needed->obj->dldags, root); 2095 objlist_push_tail(&root->dagmembers, needed->obj); 2096 } 2097 } 2098 root->dag_inited = true; 2099 } 2100 2101 static void 2102 init_marker(Obj_Entry *marker) 2103 { 2104 2105 bzero(marker, sizeof(*marker)); 2106 marker->marker = true; 2107 } 2108 2109 Obj_Entry * 2110 globallist_curr(const Obj_Entry *obj) 2111 { 2112 2113 for (;;) { 2114 if (obj == NULL) 2115 return (NULL); 2116 if (!obj->marker) 2117 return (__DECONST(Obj_Entry *, obj)); 2118 obj = TAILQ_PREV(obj, obj_entry_q, next); 2119 } 2120 } 2121 2122 Obj_Entry * 2123 globallist_next(const Obj_Entry *obj) 2124 { 2125 2126 for (;;) { 2127 obj = TAILQ_NEXT(obj, next); 2128 if (obj == NULL) 2129 return (NULL); 2130 if (!obj->marker) 2131 return (__DECONST(Obj_Entry *, obj)); 2132 } 2133 } 2134 2135 /* Prevent the object from being unmapped while the bind lock is dropped. */ 2136 static void 2137 hold_object(Obj_Entry *obj) 2138 { 2139 2140 obj->holdcount++; 2141 } 2142 2143 static void 2144 unhold_object(Obj_Entry *obj) 2145 { 2146 2147 assert(obj->holdcount > 0); 2148 if (--obj->holdcount == 0 && obj->unholdfree) 2149 release_object(obj); 2150 } 2151 2152 static void 2153 process_z(Obj_Entry *root) 2154 { 2155 const Objlist_Entry *elm; 2156 Obj_Entry *obj; 2157 2158 /* 2159 * Walk over object DAG and process every dependent object 2160 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2161 * to grow their own DAG. 2162 * 2163 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2164 * symlook_global() to work. 2165 * 2166 * For DF_1_NODELETE, the DAG should have its reference upped. 2167 */ 2168 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2169 obj = elm->obj; 2170 if (obj == NULL) 2171 continue; 2172 if (obj->z_nodelete && !obj->ref_nodel) { 2173 dbg("obj %s -z nodelete", obj->path); 2174 init_dag(obj); 2175 ref_dag(obj); 2176 obj->ref_nodel = true; 2177 } 2178 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2179 dbg("obj %s -z global", obj->path); 2180 objlist_push_tail(&list_global, obj); 2181 init_dag(obj); 2182 } 2183 } 2184 } 2185 2186 static void 2187 parse_rtld_phdr(Obj_Entry *obj) 2188 { 2189 const Elf_Phdr *ph; 2190 Elf_Addr note_start, note_end; 2191 2192 obj->stack_flags = PF_X | PF_R | PF_W; 2193 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr + 2194 obj->phsize; ph++) { 2195 switch (ph->p_type) { 2196 case PT_GNU_STACK: 2197 obj->stack_flags = ph->p_flags; 2198 break; 2199 case PT_GNU_RELRO: 2200 obj->relro_page = obj->relocbase + 2201 trunc_page(ph->p_vaddr); 2202 obj->relro_size = round_page(ph->p_memsz); 2203 break; 2204 case PT_NOTE: 2205 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 2206 note_end = note_start + ph->p_filesz; 2207 digest_notes(obj, note_start, note_end); 2208 break; 2209 } 2210 } 2211 } 2212 2213 /* 2214 * Initialize the dynamic linker. The argument is the address at which 2215 * the dynamic linker has been mapped into memory. The primary task of 2216 * this function is to relocate the dynamic linker. 2217 */ 2218 static void 2219 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2220 { 2221 Obj_Entry objtmp; /* Temporary rtld object */ 2222 const Elf_Ehdr *ehdr; 2223 const Elf_Dyn *dyn_rpath; 2224 const Elf_Dyn *dyn_soname; 2225 const Elf_Dyn *dyn_runpath; 2226 2227 #ifdef RTLD_INIT_PAGESIZES_EARLY 2228 /* The page size is required by the dynamic memory allocator. */ 2229 init_pagesizes(aux_info); 2230 #endif 2231 2232 /* 2233 * Conjure up an Obj_Entry structure for the dynamic linker. 2234 * 2235 * The "path" member can't be initialized yet because string constants 2236 * cannot yet be accessed. Below we will set it correctly. 2237 */ 2238 memset(&objtmp, 0, sizeof(objtmp)); 2239 objtmp.path = NULL; 2240 objtmp.rtld = true; 2241 objtmp.mapbase = mapbase; 2242 #ifdef PIC 2243 objtmp.relocbase = mapbase; 2244 #endif 2245 2246 objtmp.dynamic = rtld_dynamic(&objtmp); 2247 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2248 assert(objtmp.needed == NULL); 2249 #if !defined(__mips__) 2250 /* MIPS has a bogus DT_TEXTREL. */ 2251 assert(!objtmp.textrel); 2252 #endif 2253 /* 2254 * Temporarily put the dynamic linker entry into the object list, so 2255 * that symbols can be found. 2256 */ 2257 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2258 2259 ehdr = (Elf_Ehdr *)mapbase; 2260 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2261 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2262 2263 /* Initialize the object list. */ 2264 TAILQ_INIT(&obj_list); 2265 2266 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2267 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2268 2269 #ifndef RTLD_INIT_PAGESIZES_EARLY 2270 /* The page size is required by the dynamic memory allocator. */ 2271 init_pagesizes(aux_info); 2272 #endif 2273 2274 if (aux_info[AT_OSRELDATE] != NULL) 2275 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2276 2277 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2278 2279 /* Replace the path with a dynamically allocated copy. */ 2280 obj_rtld.path = xstrdup(ld_path_rtld); 2281 2282 parse_rtld_phdr(&obj_rtld); 2283 obj_enforce_relro(&obj_rtld); 2284 2285 r_debug.r_brk = r_debug_state; 2286 r_debug.r_state = RT_CONSISTENT; 2287 } 2288 2289 /* 2290 * Retrieve the array of supported page sizes. The kernel provides the page 2291 * sizes in increasing order. 2292 */ 2293 static void 2294 init_pagesizes(Elf_Auxinfo **aux_info) 2295 { 2296 static size_t psa[MAXPAGESIZES]; 2297 int mib[2]; 2298 size_t len, size; 2299 2300 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2301 NULL) { 2302 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2303 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2304 } else { 2305 len = 2; 2306 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2307 size = sizeof(psa); 2308 else { 2309 /* As a fallback, retrieve the base page size. */ 2310 size = sizeof(psa[0]); 2311 if (aux_info[AT_PAGESZ] != NULL) { 2312 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2313 goto psa_filled; 2314 } else { 2315 mib[0] = CTL_HW; 2316 mib[1] = HW_PAGESIZE; 2317 len = 2; 2318 } 2319 } 2320 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2321 _rtld_error("sysctl for hw.pagesize(s) failed"); 2322 rtld_die(); 2323 } 2324 psa_filled: 2325 pagesizes = psa; 2326 } 2327 npagesizes = size / sizeof(pagesizes[0]); 2328 /* Discard any invalid entries at the end of the array. */ 2329 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2330 npagesizes--; 2331 } 2332 2333 /* 2334 * Add the init functions from a needed object list (and its recursive 2335 * needed objects) to "list". This is not used directly; it is a helper 2336 * function for initlist_add_objects(). The write lock must be held 2337 * when this function is called. 2338 */ 2339 static void 2340 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2341 { 2342 /* Recursively process the successor needed objects. */ 2343 if (needed->next != NULL) 2344 initlist_add_neededs(needed->next, list); 2345 2346 /* Process the current needed object. */ 2347 if (needed->obj != NULL) 2348 initlist_add_objects(needed->obj, needed->obj, list); 2349 } 2350 2351 /* 2352 * Scan all of the DAGs rooted in the range of objects from "obj" to 2353 * "tail" and add their init functions to "list". This recurses over 2354 * the DAGs and ensure the proper init ordering such that each object's 2355 * needed libraries are initialized before the object itself. At the 2356 * same time, this function adds the objects to the global finalization 2357 * list "list_fini" in the opposite order. The write lock must be 2358 * held when this function is called. 2359 */ 2360 static void 2361 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2362 { 2363 Obj_Entry *nobj; 2364 2365 if (obj->init_scanned || obj->init_done) 2366 return; 2367 obj->init_scanned = true; 2368 2369 /* Recursively process the successor objects. */ 2370 nobj = globallist_next(obj); 2371 if (nobj != NULL && obj != tail) 2372 initlist_add_objects(nobj, tail, list); 2373 2374 /* Recursively process the needed objects. */ 2375 if (obj->needed != NULL) 2376 initlist_add_neededs(obj->needed, list); 2377 if (obj->needed_filtees != NULL) 2378 initlist_add_neededs(obj->needed_filtees, list); 2379 if (obj->needed_aux_filtees != NULL) 2380 initlist_add_neededs(obj->needed_aux_filtees, list); 2381 2382 /* Add the object to the init list. */ 2383 objlist_push_tail(list, obj); 2384 2385 /* Add the object to the global fini list in the reverse order. */ 2386 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2387 && !obj->on_fini_list) { 2388 objlist_push_head(&list_fini, obj); 2389 obj->on_fini_list = true; 2390 } 2391 } 2392 2393 #ifndef FPTR_TARGET 2394 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2395 #endif 2396 2397 static void 2398 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2399 { 2400 Needed_Entry *needed, *needed1; 2401 2402 for (needed = n; needed != NULL; needed = needed->next) { 2403 if (needed->obj != NULL) { 2404 dlclose_locked(needed->obj, lockstate); 2405 needed->obj = NULL; 2406 } 2407 } 2408 for (needed = n; needed != NULL; needed = needed1) { 2409 needed1 = needed->next; 2410 free(needed); 2411 } 2412 } 2413 2414 static void 2415 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2416 { 2417 2418 free_needed_filtees(obj->needed_filtees, lockstate); 2419 obj->needed_filtees = NULL; 2420 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2421 obj->needed_aux_filtees = NULL; 2422 obj->filtees_loaded = false; 2423 } 2424 2425 static void 2426 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2427 RtldLockState *lockstate) 2428 { 2429 2430 for (; needed != NULL; needed = needed->next) { 2431 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2432 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2433 RTLD_LOCAL, lockstate); 2434 } 2435 } 2436 2437 static void 2438 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2439 { 2440 2441 lock_restart_for_upgrade(lockstate); 2442 if (!obj->filtees_loaded) { 2443 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2444 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2445 obj->filtees_loaded = true; 2446 } 2447 } 2448 2449 static int 2450 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2451 { 2452 Obj_Entry *obj1; 2453 2454 for (; needed != NULL; needed = needed->next) { 2455 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2456 flags & ~RTLD_LO_NOLOAD); 2457 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2458 return (-1); 2459 } 2460 return (0); 2461 } 2462 2463 /* 2464 * Given a shared object, traverse its list of needed objects, and load 2465 * each of them. Returns 0 on success. Generates an error message and 2466 * returns -1 on failure. 2467 */ 2468 static int 2469 load_needed_objects(Obj_Entry *first, int flags) 2470 { 2471 Obj_Entry *obj; 2472 2473 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2474 if (obj->marker) 2475 continue; 2476 if (process_needed(obj, obj->needed, flags) == -1) 2477 return (-1); 2478 } 2479 return (0); 2480 } 2481 2482 static int 2483 load_preload_objects(void) 2484 { 2485 char *p = ld_preload; 2486 Obj_Entry *obj; 2487 static const char delim[] = " \t:;"; 2488 2489 if (p == NULL) 2490 return 0; 2491 2492 p += strspn(p, delim); 2493 while (*p != '\0') { 2494 size_t len = strcspn(p, delim); 2495 char savech; 2496 2497 savech = p[len]; 2498 p[len] = '\0'; 2499 obj = load_object(p, -1, NULL, 0); 2500 if (obj == NULL) 2501 return -1; /* XXX - cleanup */ 2502 obj->z_interpose = true; 2503 p[len] = savech; 2504 p += len; 2505 p += strspn(p, delim); 2506 } 2507 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2508 return 0; 2509 } 2510 2511 static const char * 2512 printable_path(const char *path) 2513 { 2514 2515 return (path == NULL ? "<unknown>" : path); 2516 } 2517 2518 /* 2519 * Load a shared object into memory, if it is not already loaded. The 2520 * object may be specified by name or by user-supplied file descriptor 2521 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2522 * duplicate is. 2523 * 2524 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2525 * on failure. 2526 */ 2527 static Obj_Entry * 2528 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2529 { 2530 Obj_Entry *obj; 2531 int fd; 2532 struct stat sb; 2533 char *path; 2534 2535 fd = -1; 2536 if (name != NULL) { 2537 TAILQ_FOREACH(obj, &obj_list, next) { 2538 if (obj->marker || obj->doomed) 2539 continue; 2540 if (object_match_name(obj, name)) 2541 return (obj); 2542 } 2543 2544 path = find_library(name, refobj, &fd); 2545 if (path == NULL) 2546 return (NULL); 2547 } else 2548 path = NULL; 2549 2550 if (fd >= 0) { 2551 /* 2552 * search_library_pathfds() opens a fresh file descriptor for the 2553 * library, so there is no need to dup(). 2554 */ 2555 } else if (fd_u == -1) { 2556 /* 2557 * If we didn't find a match by pathname, or the name is not 2558 * supplied, open the file and check again by device and inode. 2559 * This avoids false mismatches caused by multiple links or ".." 2560 * in pathnames. 2561 * 2562 * To avoid a race, we open the file and use fstat() rather than 2563 * using stat(). 2564 */ 2565 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2566 _rtld_error("Cannot open \"%s\"", path); 2567 free(path); 2568 return (NULL); 2569 } 2570 } else { 2571 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2572 if (fd == -1) { 2573 _rtld_error("Cannot dup fd"); 2574 free(path); 2575 return (NULL); 2576 } 2577 } 2578 if (fstat(fd, &sb) == -1) { 2579 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2580 close(fd); 2581 free(path); 2582 return NULL; 2583 } 2584 TAILQ_FOREACH(obj, &obj_list, next) { 2585 if (obj->marker || obj->doomed) 2586 continue; 2587 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2588 break; 2589 } 2590 if (obj != NULL && name != NULL) { 2591 object_add_name(obj, name); 2592 free(path); 2593 close(fd); 2594 return obj; 2595 } 2596 if (flags & RTLD_LO_NOLOAD) { 2597 free(path); 2598 close(fd); 2599 return (NULL); 2600 } 2601 2602 /* First use of this object, so we must map it in */ 2603 obj = do_load_object(fd, name, path, &sb, flags); 2604 if (obj == NULL) 2605 free(path); 2606 close(fd); 2607 2608 return obj; 2609 } 2610 2611 static Obj_Entry * 2612 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2613 int flags) 2614 { 2615 Obj_Entry *obj; 2616 struct statfs fs; 2617 2618 /* 2619 * but first, make sure that environment variables haven't been 2620 * used to circumvent the noexec flag on a filesystem. 2621 */ 2622 if (dangerous_ld_env) { 2623 if (fstatfs(fd, &fs) != 0) { 2624 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2625 return NULL; 2626 } 2627 if (fs.f_flags & MNT_NOEXEC) { 2628 _rtld_error("Cannot execute objects on %s", fs.f_mntonname); 2629 return NULL; 2630 } 2631 } 2632 dbg("loading \"%s\"", printable_path(path)); 2633 obj = map_object(fd, printable_path(path), sbp); 2634 if (obj == NULL) 2635 return NULL; 2636 2637 /* 2638 * If DT_SONAME is present in the object, digest_dynamic2 already 2639 * added it to the object names. 2640 */ 2641 if (name != NULL) 2642 object_add_name(obj, name); 2643 obj->path = path; 2644 if (!digest_dynamic(obj, 0)) 2645 goto errp; 2646 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2647 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2648 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { 2649 dbg("refusing to load PIE executable \"%s\"", obj->path); 2650 _rtld_error("Cannot load PIE binary %s as DSO", obj->path); 2651 goto errp; 2652 } 2653 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2654 RTLD_LO_DLOPEN) { 2655 dbg("refusing to load non-loadable \"%s\"", obj->path); 2656 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2657 goto errp; 2658 } 2659 2660 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2661 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2662 obj_count++; 2663 obj_loads++; 2664 linkmap_add(obj); /* for GDB & dlinfo() */ 2665 max_stack_flags |= obj->stack_flags; 2666 2667 dbg(" %p .. %p: %s", obj->mapbase, 2668 obj->mapbase + obj->mapsize - 1, obj->path); 2669 if (obj->textrel) 2670 dbg(" WARNING: %s has impure text", obj->path); 2671 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2672 obj->path); 2673 2674 return (obj); 2675 2676 errp: 2677 munmap(obj->mapbase, obj->mapsize); 2678 obj_free(obj); 2679 return (NULL); 2680 } 2681 2682 static Obj_Entry * 2683 obj_from_addr(const void *addr) 2684 { 2685 Obj_Entry *obj; 2686 2687 TAILQ_FOREACH(obj, &obj_list, next) { 2688 if (obj->marker) 2689 continue; 2690 if (addr < (void *) obj->mapbase) 2691 continue; 2692 if (addr < (void *)(obj->mapbase + obj->mapsize)) 2693 return obj; 2694 } 2695 return NULL; 2696 } 2697 2698 static void 2699 preinit_main(void) 2700 { 2701 Elf_Addr *preinit_addr; 2702 int index; 2703 2704 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2705 if (preinit_addr == NULL) 2706 return; 2707 2708 for (index = 0; index < obj_main->preinit_array_num; index++) { 2709 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2710 dbg("calling preinit function for %s at %p", obj_main->path, 2711 (void *)preinit_addr[index]); 2712 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2713 0, 0, obj_main->path); 2714 call_init_pointer(obj_main, preinit_addr[index]); 2715 } 2716 } 2717 } 2718 2719 /* 2720 * Call the finalization functions for each of the objects in "list" 2721 * belonging to the DAG of "root" and referenced once. If NULL "root" 2722 * is specified, every finalization function will be called regardless 2723 * of the reference count and the list elements won't be freed. All of 2724 * the objects are expected to have non-NULL fini functions. 2725 */ 2726 static void 2727 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2728 { 2729 Objlist_Entry *elm; 2730 char *saved_msg; 2731 Elf_Addr *fini_addr; 2732 int index; 2733 2734 assert(root == NULL || root->refcount == 1); 2735 2736 if (root != NULL) 2737 root->doomed = true; 2738 2739 /* 2740 * Preserve the current error message since a fini function might 2741 * call into the dynamic linker and overwrite it. 2742 */ 2743 saved_msg = errmsg_save(); 2744 do { 2745 STAILQ_FOREACH(elm, list, link) { 2746 if (root != NULL && (elm->obj->refcount != 1 || 2747 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2748 continue; 2749 /* Remove object from fini list to prevent recursive invocation. */ 2750 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2751 /* Ensure that new references cannot be acquired. */ 2752 elm->obj->doomed = true; 2753 2754 hold_object(elm->obj); 2755 lock_release(rtld_bind_lock, lockstate); 2756 /* 2757 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2758 * When this happens, DT_FINI_ARRAY is processed first. 2759 */ 2760 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2761 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2762 for (index = elm->obj->fini_array_num - 1; index >= 0; 2763 index--) { 2764 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2765 dbg("calling fini function for %s at %p", 2766 elm->obj->path, (void *)fini_addr[index]); 2767 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2768 (void *)fini_addr[index], 0, 0, elm->obj->path); 2769 call_initfini_pointer(elm->obj, fini_addr[index]); 2770 } 2771 } 2772 } 2773 if (elm->obj->fini != (Elf_Addr)NULL) { 2774 dbg("calling fini function for %s at %p", elm->obj->path, 2775 (void *)elm->obj->fini); 2776 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2777 0, 0, elm->obj->path); 2778 call_initfini_pointer(elm->obj, elm->obj->fini); 2779 } 2780 wlock_acquire(rtld_bind_lock, lockstate); 2781 unhold_object(elm->obj); 2782 /* No need to free anything if process is going down. */ 2783 if (root != NULL) 2784 free(elm); 2785 /* 2786 * We must restart the list traversal after every fini call 2787 * because a dlclose() call from the fini function or from 2788 * another thread might have modified the reference counts. 2789 */ 2790 break; 2791 } 2792 } while (elm != NULL); 2793 errmsg_restore(saved_msg); 2794 } 2795 2796 /* 2797 * Call the initialization functions for each of the objects in 2798 * "list". All of the objects are expected to have non-NULL init 2799 * functions. 2800 */ 2801 static void 2802 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2803 { 2804 Objlist_Entry *elm; 2805 Obj_Entry *obj; 2806 char *saved_msg; 2807 Elf_Addr *init_addr; 2808 void (*reg)(void (*)(void)); 2809 int index; 2810 2811 /* 2812 * Clean init_scanned flag so that objects can be rechecked and 2813 * possibly initialized earlier if any of vectors called below 2814 * cause the change by using dlopen. 2815 */ 2816 TAILQ_FOREACH(obj, &obj_list, next) { 2817 if (obj->marker) 2818 continue; 2819 obj->init_scanned = false; 2820 } 2821 2822 /* 2823 * Preserve the current error message since an init function might 2824 * call into the dynamic linker and overwrite it. 2825 */ 2826 saved_msg = errmsg_save(); 2827 STAILQ_FOREACH(elm, list, link) { 2828 if (elm->obj->init_done) /* Initialized early. */ 2829 continue; 2830 /* 2831 * Race: other thread might try to use this object before current 2832 * one completes the initialization. Not much can be done here 2833 * without better locking. 2834 */ 2835 elm->obj->init_done = true; 2836 hold_object(elm->obj); 2837 reg = NULL; 2838 if (elm->obj == obj_main && obj_main->crt_no_init) { 2839 reg = (void (*)(void (*)(void)))get_program_var_addr( 2840 "__libc_atexit", lockstate); 2841 } 2842 lock_release(rtld_bind_lock, lockstate); 2843 if (reg != NULL) { 2844 reg(rtld_exit); 2845 rtld_exit_ptr = rtld_nop_exit; 2846 } 2847 2848 /* 2849 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2850 * When this happens, DT_INIT is processed first. 2851 */ 2852 if (elm->obj->init != (Elf_Addr)NULL) { 2853 dbg("calling init function for %s at %p", elm->obj->path, 2854 (void *)elm->obj->init); 2855 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2856 0, 0, elm->obj->path); 2857 call_initfini_pointer(elm->obj, elm->obj->init); 2858 } 2859 init_addr = (Elf_Addr *)elm->obj->init_array; 2860 if (init_addr != NULL) { 2861 for (index = 0; index < elm->obj->init_array_num; index++) { 2862 if (init_addr[index] != 0 && init_addr[index] != 1) { 2863 dbg("calling init function for %s at %p", elm->obj->path, 2864 (void *)init_addr[index]); 2865 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2866 (void *)init_addr[index], 0, 0, elm->obj->path); 2867 call_init_pointer(elm->obj, init_addr[index]); 2868 } 2869 } 2870 } 2871 wlock_acquire(rtld_bind_lock, lockstate); 2872 unhold_object(elm->obj); 2873 } 2874 errmsg_restore(saved_msg); 2875 } 2876 2877 static void 2878 objlist_clear(Objlist *list) 2879 { 2880 Objlist_Entry *elm; 2881 2882 while (!STAILQ_EMPTY(list)) { 2883 elm = STAILQ_FIRST(list); 2884 STAILQ_REMOVE_HEAD(list, link); 2885 free(elm); 2886 } 2887 } 2888 2889 static Objlist_Entry * 2890 objlist_find(Objlist *list, const Obj_Entry *obj) 2891 { 2892 Objlist_Entry *elm; 2893 2894 STAILQ_FOREACH(elm, list, link) 2895 if (elm->obj == obj) 2896 return elm; 2897 return NULL; 2898 } 2899 2900 static void 2901 objlist_init(Objlist *list) 2902 { 2903 STAILQ_INIT(list); 2904 } 2905 2906 static void 2907 objlist_push_head(Objlist *list, Obj_Entry *obj) 2908 { 2909 Objlist_Entry *elm; 2910 2911 elm = NEW(Objlist_Entry); 2912 elm->obj = obj; 2913 STAILQ_INSERT_HEAD(list, elm, link); 2914 } 2915 2916 static void 2917 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2918 { 2919 Objlist_Entry *elm; 2920 2921 elm = NEW(Objlist_Entry); 2922 elm->obj = obj; 2923 STAILQ_INSERT_TAIL(list, elm, link); 2924 } 2925 2926 static void 2927 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2928 { 2929 Objlist_Entry *elm, *listelm; 2930 2931 STAILQ_FOREACH(listelm, list, link) { 2932 if (listelm->obj == listobj) 2933 break; 2934 } 2935 elm = NEW(Objlist_Entry); 2936 elm->obj = obj; 2937 if (listelm != NULL) 2938 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2939 else 2940 STAILQ_INSERT_TAIL(list, elm, link); 2941 } 2942 2943 static void 2944 objlist_remove(Objlist *list, Obj_Entry *obj) 2945 { 2946 Objlist_Entry *elm; 2947 2948 if ((elm = objlist_find(list, obj)) != NULL) { 2949 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2950 free(elm); 2951 } 2952 } 2953 2954 /* 2955 * Relocate dag rooted in the specified object. 2956 * Returns 0 on success, or -1 on failure. 2957 */ 2958 2959 static int 2960 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2961 int flags, RtldLockState *lockstate) 2962 { 2963 Objlist_Entry *elm; 2964 int error; 2965 2966 error = 0; 2967 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2968 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2969 lockstate); 2970 if (error == -1) 2971 break; 2972 } 2973 return (error); 2974 } 2975 2976 /* 2977 * Prepare for, or clean after, relocating an object marked with 2978 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2979 * segments are remapped read-write. After relocations are done, the 2980 * segment's permissions are returned back to the modes specified in 2981 * the phdrs. If any relocation happened, or always for wired 2982 * program, COW is triggered. 2983 */ 2984 static int 2985 reloc_textrel_prot(Obj_Entry *obj, bool before) 2986 { 2987 const Elf_Phdr *ph; 2988 void *base; 2989 size_t l, sz; 2990 int prot; 2991 2992 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2993 l--, ph++) { 2994 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2995 continue; 2996 base = obj->relocbase + trunc_page(ph->p_vaddr); 2997 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2998 trunc_page(ph->p_vaddr); 2999 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 3000 if (mprotect(base, sz, prot) == -1) { 3001 _rtld_error("%s: Cannot write-%sable text segment: %s", 3002 obj->path, before ? "en" : "dis", 3003 rtld_strerror(errno)); 3004 return (-1); 3005 } 3006 } 3007 return (0); 3008 } 3009 3010 /* 3011 * Relocate single object. 3012 * Returns 0 on success, or -1 on failure. 3013 */ 3014 static int 3015 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 3016 int flags, RtldLockState *lockstate) 3017 { 3018 3019 if (obj->relocated) 3020 return (0); 3021 obj->relocated = true; 3022 if (obj != rtldobj) 3023 dbg("relocating \"%s\"", obj->path); 3024 3025 if (obj->symtab == NULL || obj->strtab == NULL || 3026 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 3027 _rtld_error("%s: Shared object has no run-time symbol table", 3028 obj->path); 3029 return (-1); 3030 } 3031 3032 /* There are relocations to the write-protected text segment. */ 3033 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 3034 return (-1); 3035 3036 /* Process the non-PLT non-IFUNC relocations. */ 3037 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 3038 return (-1); 3039 3040 /* Re-protected the text segment. */ 3041 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 3042 return (-1); 3043 3044 /* Set the special PLT or GOT entries. */ 3045 init_pltgot(obj); 3046 3047 /* Process the PLT relocations. */ 3048 if (reloc_plt(obj, flags, lockstate) == -1) 3049 return (-1); 3050 /* Relocate the jump slots if we are doing immediate binding. */ 3051 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 3052 lockstate) == -1) 3053 return (-1); 3054 3055 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 3056 return (-1); 3057 3058 /* 3059 * Set up the magic number and version in the Obj_Entry. These 3060 * were checked in the crt1.o from the original ElfKit, so we 3061 * set them for backward compatibility. 3062 */ 3063 obj->magic = RTLD_MAGIC; 3064 obj->version = RTLD_VERSION; 3065 3066 return (0); 3067 } 3068 3069 /* 3070 * Relocate newly-loaded shared objects. The argument is a pointer to 3071 * the Obj_Entry for the first such object. All objects from the first 3072 * to the end of the list of objects are relocated. Returns 0 on success, 3073 * or -1 on failure. 3074 */ 3075 static int 3076 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 3077 int flags, RtldLockState *lockstate) 3078 { 3079 Obj_Entry *obj; 3080 int error; 3081 3082 for (error = 0, obj = first; obj != NULL; 3083 obj = TAILQ_NEXT(obj, next)) { 3084 if (obj->marker) 3085 continue; 3086 error = relocate_object(obj, bind_now, rtldobj, flags, 3087 lockstate); 3088 if (error == -1) 3089 break; 3090 } 3091 return (error); 3092 } 3093 3094 /* 3095 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 3096 * referencing STT_GNU_IFUNC symbols is postponed till the other 3097 * relocations are done. The indirect functions specified as 3098 * ifunc are allowed to call other symbols, so we need to have 3099 * objects relocated before asking for resolution from indirects. 3100 * 3101 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 3102 * instead of the usual lazy handling of PLT slots. It is 3103 * consistent with how GNU does it. 3104 */ 3105 static int 3106 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 3107 RtldLockState *lockstate) 3108 { 3109 3110 if (obj->ifuncs_resolved) 3111 return (0); 3112 obj->ifuncs_resolved = true; 3113 if (!obj->irelative && !obj->irelative_nonplt && 3114 !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 3115 return (0); 3116 if (obj_disable_relro(obj) == -1 || 3117 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 3118 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, 3119 lockstate) == -1) || 3120 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 3121 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 3122 obj_enforce_relro(obj) == -1) 3123 return (-1); 3124 return (0); 3125 } 3126 3127 static int 3128 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 3129 RtldLockState *lockstate) 3130 { 3131 Objlist_Entry *elm; 3132 Obj_Entry *obj; 3133 3134 STAILQ_FOREACH(elm, list, link) { 3135 obj = elm->obj; 3136 if (obj->marker) 3137 continue; 3138 if (resolve_object_ifunc(obj, bind_now, flags, 3139 lockstate) == -1) 3140 return (-1); 3141 } 3142 return (0); 3143 } 3144 3145 /* 3146 * Cleanup procedure. It will be called (by the atexit mechanism) just 3147 * before the process exits. 3148 */ 3149 static void 3150 rtld_exit(void) 3151 { 3152 RtldLockState lockstate; 3153 3154 wlock_acquire(rtld_bind_lock, &lockstate); 3155 dbg("rtld_exit()"); 3156 objlist_call_fini(&list_fini, NULL, &lockstate); 3157 /* No need to remove the items from the list, since we are exiting. */ 3158 if (!libmap_disable) 3159 lm_fini(); 3160 lock_release(rtld_bind_lock, &lockstate); 3161 } 3162 3163 static void 3164 rtld_nop_exit(void) 3165 { 3166 } 3167 3168 /* 3169 * Iterate over a search path, translate each element, and invoke the 3170 * callback on the result. 3171 */ 3172 static void * 3173 path_enumerate(const char *path, path_enum_proc callback, 3174 const char *refobj_path, void *arg) 3175 { 3176 const char *trans; 3177 if (path == NULL) 3178 return (NULL); 3179 3180 path += strspn(path, ":;"); 3181 while (*path != '\0') { 3182 size_t len; 3183 char *res; 3184 3185 len = strcspn(path, ":;"); 3186 trans = lm_findn(refobj_path, path, len); 3187 if (trans) 3188 res = callback(trans, strlen(trans), arg); 3189 else 3190 res = callback(path, len, arg); 3191 3192 if (res != NULL) 3193 return (res); 3194 3195 path += len; 3196 path += strspn(path, ":;"); 3197 } 3198 3199 return (NULL); 3200 } 3201 3202 struct try_library_args { 3203 const char *name; 3204 size_t namelen; 3205 char *buffer; 3206 size_t buflen; 3207 int fd; 3208 }; 3209 3210 static void * 3211 try_library_path(const char *dir, size_t dirlen, void *param) 3212 { 3213 struct try_library_args *arg; 3214 int fd; 3215 3216 arg = param; 3217 if (*dir == '/' || trust) { 3218 char *pathname; 3219 3220 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3221 return (NULL); 3222 3223 pathname = arg->buffer; 3224 strncpy(pathname, dir, dirlen); 3225 pathname[dirlen] = '/'; 3226 strcpy(pathname + dirlen + 1, arg->name); 3227 3228 dbg(" Trying \"%s\"", pathname); 3229 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3230 if (fd >= 0) { 3231 dbg(" Opened \"%s\", fd %d", pathname, fd); 3232 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3233 strcpy(pathname, arg->buffer); 3234 arg->fd = fd; 3235 return (pathname); 3236 } else { 3237 dbg(" Failed to open \"%s\": %s", 3238 pathname, rtld_strerror(errno)); 3239 } 3240 } 3241 return (NULL); 3242 } 3243 3244 static char * 3245 search_library_path(const char *name, const char *path, 3246 const char *refobj_path, int *fdp) 3247 { 3248 char *p; 3249 struct try_library_args arg; 3250 3251 if (path == NULL) 3252 return NULL; 3253 3254 arg.name = name; 3255 arg.namelen = strlen(name); 3256 arg.buffer = xmalloc(PATH_MAX); 3257 arg.buflen = PATH_MAX; 3258 arg.fd = -1; 3259 3260 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3261 *fdp = arg.fd; 3262 3263 free(arg.buffer); 3264 3265 return (p); 3266 } 3267 3268 3269 /* 3270 * Finds the library with the given name using the directory descriptors 3271 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3272 * 3273 * Returns a freshly-opened close-on-exec file descriptor for the library, 3274 * or -1 if the library cannot be found. 3275 */ 3276 static char * 3277 search_library_pathfds(const char *name, const char *path, int *fdp) 3278 { 3279 char *envcopy, *fdstr, *found, *last_token; 3280 size_t len; 3281 int dirfd, fd; 3282 3283 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3284 3285 /* Don't load from user-specified libdirs into setuid binaries. */ 3286 if (!trust) 3287 return (NULL); 3288 3289 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3290 if (path == NULL) 3291 return (NULL); 3292 3293 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3294 if (name[0] == '/') { 3295 dbg("Absolute path (%s) passed to %s", name, __func__); 3296 return (NULL); 3297 } 3298 3299 /* 3300 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3301 * copy of the path, as strtok_r rewrites separator tokens 3302 * with '\0'. 3303 */ 3304 found = NULL; 3305 envcopy = xstrdup(path); 3306 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3307 fdstr = strtok_r(NULL, ":", &last_token)) { 3308 dirfd = parse_integer(fdstr); 3309 if (dirfd < 0) { 3310 _rtld_error("failed to parse directory FD: '%s'", 3311 fdstr); 3312 break; 3313 } 3314 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3315 if (fd >= 0) { 3316 *fdp = fd; 3317 len = strlen(fdstr) + strlen(name) + 3; 3318 found = xmalloc(len); 3319 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3320 _rtld_error("error generating '%d/%s'", 3321 dirfd, name); 3322 rtld_die(); 3323 } 3324 dbg("open('%s') => %d", found, fd); 3325 break; 3326 } 3327 } 3328 free(envcopy); 3329 3330 return (found); 3331 } 3332 3333 3334 int 3335 dlclose(void *handle) 3336 { 3337 RtldLockState lockstate; 3338 int error; 3339 3340 wlock_acquire(rtld_bind_lock, &lockstate); 3341 error = dlclose_locked(handle, &lockstate); 3342 lock_release(rtld_bind_lock, &lockstate); 3343 return (error); 3344 } 3345 3346 static int 3347 dlclose_locked(void *handle, RtldLockState *lockstate) 3348 { 3349 Obj_Entry *root; 3350 3351 root = dlcheck(handle); 3352 if (root == NULL) 3353 return -1; 3354 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3355 root->path); 3356 3357 /* Unreference the object and its dependencies. */ 3358 root->dl_refcount--; 3359 3360 if (root->refcount == 1) { 3361 /* 3362 * The object will be no longer referenced, so we must unload it. 3363 * First, call the fini functions. 3364 */ 3365 objlist_call_fini(&list_fini, root, lockstate); 3366 3367 unref_dag(root); 3368 3369 /* Finish cleaning up the newly-unreferenced objects. */ 3370 GDB_STATE(RT_DELETE,&root->linkmap); 3371 unload_object(root, lockstate); 3372 GDB_STATE(RT_CONSISTENT,NULL); 3373 } else 3374 unref_dag(root); 3375 3376 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3377 return 0; 3378 } 3379 3380 char * 3381 dlerror(void) 3382 { 3383 char *msg = error_message; 3384 error_message = NULL; 3385 return msg; 3386 } 3387 3388 /* 3389 * This function is deprecated and has no effect. 3390 */ 3391 void 3392 dllockinit(void *context, 3393 void *(*_lock_create)(void *context) __unused, 3394 void (*_rlock_acquire)(void *lock) __unused, 3395 void (*_wlock_acquire)(void *lock) __unused, 3396 void (*_lock_release)(void *lock) __unused, 3397 void (*_lock_destroy)(void *lock) __unused, 3398 void (*context_destroy)(void *context)) 3399 { 3400 static void *cur_context; 3401 static void (*cur_context_destroy)(void *); 3402 3403 /* Just destroy the context from the previous call, if necessary. */ 3404 if (cur_context_destroy != NULL) 3405 cur_context_destroy(cur_context); 3406 cur_context = context; 3407 cur_context_destroy = context_destroy; 3408 } 3409 3410 void * 3411 dlopen(const char *name, int mode) 3412 { 3413 3414 return (rtld_dlopen(name, -1, mode)); 3415 } 3416 3417 void * 3418 fdlopen(int fd, int mode) 3419 { 3420 3421 return (rtld_dlopen(NULL, fd, mode)); 3422 } 3423 3424 static void * 3425 rtld_dlopen(const char *name, int fd, int mode) 3426 { 3427 RtldLockState lockstate; 3428 int lo_flags; 3429 3430 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3431 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3432 if (ld_tracing != NULL) { 3433 rlock_acquire(rtld_bind_lock, &lockstate); 3434 if (sigsetjmp(lockstate.env, 0) != 0) 3435 lock_upgrade(rtld_bind_lock, &lockstate); 3436 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); 3437 lock_release(rtld_bind_lock, &lockstate); 3438 } 3439 lo_flags = RTLD_LO_DLOPEN; 3440 if (mode & RTLD_NODELETE) 3441 lo_flags |= RTLD_LO_NODELETE; 3442 if (mode & RTLD_NOLOAD) 3443 lo_flags |= RTLD_LO_NOLOAD; 3444 if (mode & RTLD_DEEPBIND) 3445 lo_flags |= RTLD_LO_DEEPBIND; 3446 if (ld_tracing != NULL) 3447 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; 3448 3449 return (dlopen_object(name, fd, obj_main, lo_flags, 3450 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3451 } 3452 3453 static void 3454 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3455 { 3456 3457 obj->dl_refcount--; 3458 unref_dag(obj); 3459 if (obj->refcount == 0) 3460 unload_object(obj, lockstate); 3461 } 3462 3463 static Obj_Entry * 3464 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3465 int mode, RtldLockState *lockstate) 3466 { 3467 Obj_Entry *old_obj_tail; 3468 Obj_Entry *obj; 3469 Objlist initlist; 3470 RtldLockState mlockstate; 3471 int result; 3472 3473 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", 3474 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" : 3475 refobj->path, lo_flags, mode); 3476 objlist_init(&initlist); 3477 3478 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3479 wlock_acquire(rtld_bind_lock, &mlockstate); 3480 lockstate = &mlockstate; 3481 } 3482 GDB_STATE(RT_ADD,NULL); 3483 3484 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3485 obj = NULL; 3486 if (name == NULL && fd == -1) { 3487 obj = obj_main; 3488 obj->refcount++; 3489 } else { 3490 obj = load_object(name, fd, refobj, lo_flags); 3491 } 3492 3493 if (obj) { 3494 obj->dl_refcount++; 3495 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3496 objlist_push_tail(&list_global, obj); 3497 if (globallist_next(old_obj_tail) != NULL) { 3498 /* We loaded something new. */ 3499 assert(globallist_next(old_obj_tail) == obj); 3500 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3501 obj->symbolic = true; 3502 result = 0; 3503 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && 3504 obj->static_tls && !allocate_tls_offset(obj)) { 3505 _rtld_error("%s: No space available " 3506 "for static Thread Local Storage", obj->path); 3507 result = -1; 3508 } 3509 if (result != -1) 3510 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3511 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); 3512 init_dag(obj); 3513 ref_dag(obj); 3514 if (result != -1) 3515 result = rtld_verify_versions(&obj->dagmembers); 3516 if (result != -1 && ld_tracing) 3517 goto trace; 3518 if (result == -1 || relocate_object_dag(obj, 3519 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3520 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3521 lockstate) == -1) { 3522 dlopen_cleanup(obj, lockstate); 3523 obj = NULL; 3524 } else if (lo_flags & RTLD_LO_EARLY) { 3525 /* 3526 * Do not call the init functions for early loaded 3527 * filtees. The image is still not initialized enough 3528 * for them to work. 3529 * 3530 * Our object is found by the global object list and 3531 * will be ordered among all init calls done right 3532 * before transferring control to main. 3533 */ 3534 } else { 3535 /* Make list of init functions to call. */ 3536 initlist_add_objects(obj, obj, &initlist); 3537 } 3538 /* 3539 * Process all no_delete or global objects here, given 3540 * them own DAGs to prevent their dependencies from being 3541 * unloaded. This has to be done after we have loaded all 3542 * of the dependencies, so that we do not miss any. 3543 */ 3544 if (obj != NULL) 3545 process_z(obj); 3546 } else { 3547 /* 3548 * Bump the reference counts for objects on this DAG. If 3549 * this is the first dlopen() call for the object that was 3550 * already loaded as a dependency, initialize the dag 3551 * starting at it. 3552 */ 3553 init_dag(obj); 3554 ref_dag(obj); 3555 3556 if ((lo_flags & RTLD_LO_TRACE) != 0) 3557 goto trace; 3558 } 3559 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3560 obj->z_nodelete) && !obj->ref_nodel) { 3561 dbg("obj %s nodelete", obj->path); 3562 ref_dag(obj); 3563 obj->z_nodelete = obj->ref_nodel = true; 3564 } 3565 } 3566 3567 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3568 name); 3569 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3570 3571 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3572 map_stacks_exec(lockstate); 3573 if (obj != NULL) 3574 distribute_static_tls(&initlist, lockstate); 3575 } 3576 3577 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3578 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3579 lockstate) == -1) { 3580 objlist_clear(&initlist); 3581 dlopen_cleanup(obj, lockstate); 3582 if (lockstate == &mlockstate) 3583 lock_release(rtld_bind_lock, lockstate); 3584 return (NULL); 3585 } 3586 3587 if (!(lo_flags & RTLD_LO_EARLY)) { 3588 /* Call the init functions. */ 3589 objlist_call_init(&initlist, lockstate); 3590 } 3591 objlist_clear(&initlist); 3592 if (lockstate == &mlockstate) 3593 lock_release(rtld_bind_lock, lockstate); 3594 return obj; 3595 trace: 3596 trace_loaded_objects(obj); 3597 if (lockstate == &mlockstate) 3598 lock_release(rtld_bind_lock, lockstate); 3599 exit(0); 3600 } 3601 3602 static void * 3603 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3604 int flags) 3605 { 3606 DoneList donelist; 3607 const Obj_Entry *obj, *defobj; 3608 const Elf_Sym *def; 3609 SymLook req; 3610 RtldLockState lockstate; 3611 tls_index ti; 3612 void *sym; 3613 int res; 3614 3615 def = NULL; 3616 defobj = NULL; 3617 symlook_init(&req, name); 3618 req.ventry = ve; 3619 req.flags = flags | SYMLOOK_IN_PLT; 3620 req.lockstate = &lockstate; 3621 3622 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3623 rlock_acquire(rtld_bind_lock, &lockstate); 3624 if (sigsetjmp(lockstate.env, 0) != 0) 3625 lock_upgrade(rtld_bind_lock, &lockstate); 3626 if (handle == NULL || handle == RTLD_NEXT || 3627 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3628 3629 if ((obj = obj_from_addr(retaddr)) == NULL) { 3630 _rtld_error("Cannot determine caller's shared object"); 3631 lock_release(rtld_bind_lock, &lockstate); 3632 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3633 return NULL; 3634 } 3635 if (handle == NULL) { /* Just the caller's shared object. */ 3636 res = symlook_obj(&req, obj); 3637 if (res == 0) { 3638 def = req.sym_out; 3639 defobj = req.defobj_out; 3640 } 3641 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3642 handle == RTLD_SELF) { /* ... caller included */ 3643 if (handle == RTLD_NEXT) 3644 obj = globallist_next(obj); 3645 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3646 if (obj->marker) 3647 continue; 3648 res = symlook_obj(&req, obj); 3649 if (res == 0) { 3650 if (def == NULL || 3651 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3652 def = req.sym_out; 3653 defobj = req.defobj_out; 3654 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3655 break; 3656 } 3657 } 3658 } 3659 /* 3660 * Search the dynamic linker itself, and possibly resolve the 3661 * symbol from there. This is how the application links to 3662 * dynamic linker services such as dlopen. 3663 */ 3664 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3665 res = symlook_obj(&req, &obj_rtld); 3666 if (res == 0) { 3667 def = req.sym_out; 3668 defobj = req.defobj_out; 3669 } 3670 } 3671 } else { 3672 assert(handle == RTLD_DEFAULT); 3673 res = symlook_default(&req, obj); 3674 if (res == 0) { 3675 defobj = req.defobj_out; 3676 def = req.sym_out; 3677 } 3678 } 3679 } else { 3680 if ((obj = dlcheck(handle)) == NULL) { 3681 lock_release(rtld_bind_lock, &lockstate); 3682 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3683 return NULL; 3684 } 3685 3686 donelist_init(&donelist); 3687 if (obj->mainprog) { 3688 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3689 res = symlook_global(&req, &donelist); 3690 if (res == 0) { 3691 def = req.sym_out; 3692 defobj = req.defobj_out; 3693 } 3694 /* 3695 * Search the dynamic linker itself, and possibly resolve the 3696 * symbol from there. This is how the application links to 3697 * dynamic linker services such as dlopen. 3698 */ 3699 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3700 res = symlook_obj(&req, &obj_rtld); 3701 if (res == 0) { 3702 def = req.sym_out; 3703 defobj = req.defobj_out; 3704 } 3705 } 3706 } 3707 else { 3708 /* Search the whole DAG rooted at the given object. */ 3709 res = symlook_list(&req, &obj->dagmembers, &donelist); 3710 if (res == 0) { 3711 def = req.sym_out; 3712 defobj = req.defobj_out; 3713 } 3714 } 3715 } 3716 3717 if (def != NULL) { 3718 lock_release(rtld_bind_lock, &lockstate); 3719 3720 /* 3721 * The value required by the caller is derived from the value 3722 * of the symbol. this is simply the relocated value of the 3723 * symbol. 3724 */ 3725 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3726 sym = make_function_pointer(def, defobj); 3727 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3728 sym = rtld_resolve_ifunc(defobj, def); 3729 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3730 ti.ti_module = defobj->tlsindex; 3731 ti.ti_offset = def->st_value; 3732 sym = __tls_get_addr(&ti); 3733 } else 3734 sym = defobj->relocbase + def->st_value; 3735 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3736 return (sym); 3737 } 3738 3739 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3740 ve != NULL ? ve->name : ""); 3741 lock_release(rtld_bind_lock, &lockstate); 3742 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3743 return NULL; 3744 } 3745 3746 void * 3747 dlsym(void *handle, const char *name) 3748 { 3749 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3750 SYMLOOK_DLSYM); 3751 } 3752 3753 dlfunc_t 3754 dlfunc(void *handle, const char *name) 3755 { 3756 union { 3757 void *d; 3758 dlfunc_t f; 3759 } rv; 3760 3761 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3762 SYMLOOK_DLSYM); 3763 return (rv.f); 3764 } 3765 3766 void * 3767 dlvsym(void *handle, const char *name, const char *version) 3768 { 3769 Ver_Entry ventry; 3770 3771 ventry.name = version; 3772 ventry.file = NULL; 3773 ventry.hash = elf_hash(version); 3774 ventry.flags= 0; 3775 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3776 SYMLOOK_DLSYM); 3777 } 3778 3779 int 3780 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3781 { 3782 const Obj_Entry *obj; 3783 RtldLockState lockstate; 3784 3785 rlock_acquire(rtld_bind_lock, &lockstate); 3786 obj = obj_from_addr(addr); 3787 if (obj == NULL) { 3788 _rtld_error("No shared object contains address"); 3789 lock_release(rtld_bind_lock, &lockstate); 3790 return (0); 3791 } 3792 rtld_fill_dl_phdr_info(obj, phdr_info); 3793 lock_release(rtld_bind_lock, &lockstate); 3794 return (1); 3795 } 3796 3797 int 3798 dladdr(const void *addr, Dl_info *info) 3799 { 3800 const Obj_Entry *obj; 3801 const Elf_Sym *def; 3802 void *symbol_addr; 3803 unsigned long symoffset; 3804 RtldLockState lockstate; 3805 3806 rlock_acquire(rtld_bind_lock, &lockstate); 3807 obj = obj_from_addr(addr); 3808 if (obj == NULL) { 3809 _rtld_error("No shared object contains address"); 3810 lock_release(rtld_bind_lock, &lockstate); 3811 return 0; 3812 } 3813 info->dli_fname = obj->path; 3814 info->dli_fbase = obj->mapbase; 3815 info->dli_saddr = (void *)0; 3816 info->dli_sname = NULL; 3817 3818 /* 3819 * Walk the symbol list looking for the symbol whose address is 3820 * closest to the address sent in. 3821 */ 3822 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3823 def = obj->symtab + symoffset; 3824 3825 /* 3826 * For skip the symbol if st_shndx is either SHN_UNDEF or 3827 * SHN_COMMON. 3828 */ 3829 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3830 continue; 3831 3832 /* 3833 * If the symbol is greater than the specified address, or if it 3834 * is further away from addr than the current nearest symbol, 3835 * then reject it. 3836 */ 3837 symbol_addr = obj->relocbase + def->st_value; 3838 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3839 continue; 3840 3841 /* Update our idea of the nearest symbol. */ 3842 info->dli_sname = obj->strtab + def->st_name; 3843 info->dli_saddr = symbol_addr; 3844 3845 /* Exact match? */ 3846 if (info->dli_saddr == addr) 3847 break; 3848 } 3849 lock_release(rtld_bind_lock, &lockstate); 3850 return 1; 3851 } 3852 3853 int 3854 dlinfo(void *handle, int request, void *p) 3855 { 3856 const Obj_Entry *obj; 3857 RtldLockState lockstate; 3858 int error; 3859 3860 rlock_acquire(rtld_bind_lock, &lockstate); 3861 3862 if (handle == NULL || handle == RTLD_SELF) { 3863 void *retaddr; 3864 3865 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3866 if ((obj = obj_from_addr(retaddr)) == NULL) 3867 _rtld_error("Cannot determine caller's shared object"); 3868 } else 3869 obj = dlcheck(handle); 3870 3871 if (obj == NULL) { 3872 lock_release(rtld_bind_lock, &lockstate); 3873 return (-1); 3874 } 3875 3876 error = 0; 3877 switch (request) { 3878 case RTLD_DI_LINKMAP: 3879 *((struct link_map const **)p) = &obj->linkmap; 3880 break; 3881 case RTLD_DI_ORIGIN: 3882 error = rtld_dirname(obj->path, p); 3883 break; 3884 3885 case RTLD_DI_SERINFOSIZE: 3886 case RTLD_DI_SERINFO: 3887 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3888 break; 3889 3890 default: 3891 _rtld_error("Invalid request %d passed to dlinfo()", request); 3892 error = -1; 3893 } 3894 3895 lock_release(rtld_bind_lock, &lockstate); 3896 3897 return (error); 3898 } 3899 3900 static void 3901 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3902 { 3903 3904 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3905 phdr_info->dlpi_name = obj->path; 3906 phdr_info->dlpi_phdr = obj->phdr; 3907 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3908 phdr_info->dlpi_tls_modid = obj->tlsindex; 3909 phdr_info->dlpi_tls_data = obj->tlsinit; 3910 phdr_info->dlpi_adds = obj_loads; 3911 phdr_info->dlpi_subs = obj_loads - obj_count; 3912 } 3913 3914 int 3915 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3916 { 3917 struct dl_phdr_info phdr_info; 3918 Obj_Entry *obj, marker; 3919 RtldLockState bind_lockstate, phdr_lockstate; 3920 int error; 3921 3922 init_marker(&marker); 3923 error = 0; 3924 3925 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3926 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3927 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3928 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3929 rtld_fill_dl_phdr_info(obj, &phdr_info); 3930 hold_object(obj); 3931 lock_release(rtld_bind_lock, &bind_lockstate); 3932 3933 error = callback(&phdr_info, sizeof phdr_info, param); 3934 3935 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3936 unhold_object(obj); 3937 obj = globallist_next(&marker); 3938 TAILQ_REMOVE(&obj_list, &marker, next); 3939 if (error != 0) { 3940 lock_release(rtld_bind_lock, &bind_lockstate); 3941 lock_release(rtld_phdr_lock, &phdr_lockstate); 3942 return (error); 3943 } 3944 } 3945 3946 if (error == 0) { 3947 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3948 lock_release(rtld_bind_lock, &bind_lockstate); 3949 error = callback(&phdr_info, sizeof(phdr_info), param); 3950 } 3951 lock_release(rtld_phdr_lock, &phdr_lockstate); 3952 return (error); 3953 } 3954 3955 static void * 3956 fill_search_info(const char *dir, size_t dirlen, void *param) 3957 { 3958 struct fill_search_info_args *arg; 3959 3960 arg = param; 3961 3962 if (arg->request == RTLD_DI_SERINFOSIZE) { 3963 arg->serinfo->dls_cnt ++; 3964 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3965 } else { 3966 struct dl_serpath *s_entry; 3967 3968 s_entry = arg->serpath; 3969 s_entry->dls_name = arg->strspace; 3970 s_entry->dls_flags = arg->flags; 3971 3972 strncpy(arg->strspace, dir, dirlen); 3973 arg->strspace[dirlen] = '\0'; 3974 3975 arg->strspace += dirlen + 1; 3976 arg->serpath++; 3977 } 3978 3979 return (NULL); 3980 } 3981 3982 static int 3983 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3984 { 3985 struct dl_serinfo _info; 3986 struct fill_search_info_args args; 3987 3988 args.request = RTLD_DI_SERINFOSIZE; 3989 args.serinfo = &_info; 3990 3991 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3992 _info.dls_cnt = 0; 3993 3994 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3995 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3996 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3997 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3998 if (!obj->z_nodeflib) 3999 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 4000 4001 4002 if (request == RTLD_DI_SERINFOSIZE) { 4003 info->dls_size = _info.dls_size; 4004 info->dls_cnt = _info.dls_cnt; 4005 return (0); 4006 } 4007 4008 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 4009 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 4010 return (-1); 4011 } 4012 4013 args.request = RTLD_DI_SERINFO; 4014 args.serinfo = info; 4015 args.serpath = &info->dls_serpath[0]; 4016 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 4017 4018 args.flags = LA_SER_RUNPATH; 4019 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 4020 return (-1); 4021 4022 args.flags = LA_SER_LIBPATH; 4023 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 4024 return (-1); 4025 4026 args.flags = LA_SER_RUNPATH; 4027 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 4028 return (-1); 4029 4030 args.flags = LA_SER_CONFIG; 4031 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 4032 != NULL) 4033 return (-1); 4034 4035 args.flags = LA_SER_DEFAULT; 4036 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 4037 fill_search_info, NULL, &args) != NULL) 4038 return (-1); 4039 return (0); 4040 } 4041 4042 static int 4043 rtld_dirname(const char *path, char *bname) 4044 { 4045 const char *endp; 4046 4047 /* Empty or NULL string gets treated as "." */ 4048 if (path == NULL || *path == '\0') { 4049 bname[0] = '.'; 4050 bname[1] = '\0'; 4051 return (0); 4052 } 4053 4054 /* Strip trailing slashes */ 4055 endp = path + strlen(path) - 1; 4056 while (endp > path && *endp == '/') 4057 endp--; 4058 4059 /* Find the start of the dir */ 4060 while (endp > path && *endp != '/') 4061 endp--; 4062 4063 /* Either the dir is "/" or there are no slashes */ 4064 if (endp == path) { 4065 bname[0] = *endp == '/' ? '/' : '.'; 4066 bname[1] = '\0'; 4067 return (0); 4068 } else { 4069 do { 4070 endp--; 4071 } while (endp > path && *endp == '/'); 4072 } 4073 4074 if (endp - path + 2 > PATH_MAX) 4075 { 4076 _rtld_error("Filename is too long: %s", path); 4077 return(-1); 4078 } 4079 4080 strncpy(bname, path, endp - path + 1); 4081 bname[endp - path + 1] = '\0'; 4082 return (0); 4083 } 4084 4085 static int 4086 rtld_dirname_abs(const char *path, char *base) 4087 { 4088 char *last; 4089 4090 if (realpath(path, base) == NULL) { 4091 _rtld_error("realpath \"%s\" failed (%s)", path, 4092 rtld_strerror(errno)); 4093 return (-1); 4094 } 4095 dbg("%s -> %s", path, base); 4096 last = strrchr(base, '/'); 4097 if (last == NULL) { 4098 _rtld_error("non-abs result from realpath \"%s\"", path); 4099 return (-1); 4100 } 4101 if (last != base) 4102 *last = '\0'; 4103 return (0); 4104 } 4105 4106 static void 4107 linkmap_add(Obj_Entry *obj) 4108 { 4109 struct link_map *l, *prev; 4110 4111 l = &obj->linkmap; 4112 l->l_name = obj->path; 4113 l->l_base = obj->mapbase; 4114 l->l_ld = obj->dynamic; 4115 l->l_addr = obj->relocbase; 4116 4117 if (r_debug.r_map == NULL) { 4118 r_debug.r_map = l; 4119 return; 4120 } 4121 4122 /* 4123 * Scan to the end of the list, but not past the entry for the 4124 * dynamic linker, which we want to keep at the very end. 4125 */ 4126 for (prev = r_debug.r_map; 4127 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 4128 prev = prev->l_next) 4129 ; 4130 4131 /* Link in the new entry. */ 4132 l->l_prev = prev; 4133 l->l_next = prev->l_next; 4134 if (l->l_next != NULL) 4135 l->l_next->l_prev = l; 4136 prev->l_next = l; 4137 } 4138 4139 static void 4140 linkmap_delete(Obj_Entry *obj) 4141 { 4142 struct link_map *l; 4143 4144 l = &obj->linkmap; 4145 if (l->l_prev == NULL) { 4146 if ((r_debug.r_map = l->l_next) != NULL) 4147 l->l_next->l_prev = NULL; 4148 return; 4149 } 4150 4151 if ((l->l_prev->l_next = l->l_next) != NULL) 4152 l->l_next->l_prev = l->l_prev; 4153 } 4154 4155 /* 4156 * Function for the debugger to set a breakpoint on to gain control. 4157 * 4158 * The two parameters allow the debugger to easily find and determine 4159 * what the runtime loader is doing and to whom it is doing it. 4160 * 4161 * When the loadhook trap is hit (r_debug_state, set at program 4162 * initialization), the arguments can be found on the stack: 4163 * 4164 * +8 struct link_map *m 4165 * +4 struct r_debug *rd 4166 * +0 RetAddr 4167 */ 4168 void 4169 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused) 4170 { 4171 /* 4172 * The following is a hack to force the compiler to emit calls to 4173 * this function, even when optimizing. If the function is empty, 4174 * the compiler is not obliged to emit any code for calls to it, 4175 * even when marked __noinline. However, gdb depends on those 4176 * calls being made. 4177 */ 4178 __compiler_membar(); 4179 } 4180 4181 /* 4182 * A function called after init routines have completed. This can be used to 4183 * break before a program's entry routine is called, and can be used when 4184 * main is not available in the symbol table. 4185 */ 4186 void 4187 _r_debug_postinit(struct link_map *m __unused) 4188 { 4189 4190 /* See r_debug_state(). */ 4191 __compiler_membar(); 4192 } 4193 4194 static void 4195 release_object(Obj_Entry *obj) 4196 { 4197 4198 if (obj->holdcount > 0) { 4199 obj->unholdfree = true; 4200 return; 4201 } 4202 munmap(obj->mapbase, obj->mapsize); 4203 linkmap_delete(obj); 4204 obj_free(obj); 4205 } 4206 4207 /* 4208 * Get address of the pointer variable in the main program. 4209 * Prefer non-weak symbol over the weak one. 4210 */ 4211 static const void ** 4212 get_program_var_addr(const char *name, RtldLockState *lockstate) 4213 { 4214 SymLook req; 4215 DoneList donelist; 4216 4217 symlook_init(&req, name); 4218 req.lockstate = lockstate; 4219 donelist_init(&donelist); 4220 if (symlook_global(&req, &donelist) != 0) 4221 return (NULL); 4222 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4223 return ((const void **)make_function_pointer(req.sym_out, 4224 req.defobj_out)); 4225 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4226 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4227 else 4228 return ((const void **)(req.defobj_out->relocbase + 4229 req.sym_out->st_value)); 4230 } 4231 4232 /* 4233 * Set a pointer variable in the main program to the given value. This 4234 * is used to set key variables such as "environ" before any of the 4235 * init functions are called. 4236 */ 4237 static void 4238 set_program_var(const char *name, const void *value) 4239 { 4240 const void **addr; 4241 4242 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4243 dbg("\"%s\": *%p <-- %p", name, addr, value); 4244 *addr = value; 4245 } 4246 } 4247 4248 /* 4249 * Search the global objects, including dependencies and main object, 4250 * for the given symbol. 4251 */ 4252 static int 4253 symlook_global(SymLook *req, DoneList *donelist) 4254 { 4255 SymLook req1; 4256 const Objlist_Entry *elm; 4257 int res; 4258 4259 symlook_init_from_req(&req1, req); 4260 4261 /* Search all objects loaded at program start up. */ 4262 if (req->defobj_out == NULL || 4263 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4264 res = symlook_list(&req1, &list_main, donelist); 4265 if (res == 0 && (req->defobj_out == NULL || 4266 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4267 req->sym_out = req1.sym_out; 4268 req->defobj_out = req1.defobj_out; 4269 assert(req->defobj_out != NULL); 4270 } 4271 } 4272 4273 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4274 STAILQ_FOREACH(elm, &list_global, link) { 4275 if (req->defobj_out != NULL && 4276 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4277 break; 4278 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4279 if (res == 0 && (req->defobj_out == NULL || 4280 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4281 req->sym_out = req1.sym_out; 4282 req->defobj_out = req1.defobj_out; 4283 assert(req->defobj_out != NULL); 4284 } 4285 } 4286 4287 return (req->sym_out != NULL ? 0 : ESRCH); 4288 } 4289 4290 /* 4291 * Given a symbol name in a referencing object, find the corresponding 4292 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4293 * no definition was found. Returns a pointer to the Obj_Entry of the 4294 * defining object via the reference parameter DEFOBJ_OUT. 4295 */ 4296 static int 4297 symlook_default(SymLook *req, const Obj_Entry *refobj) 4298 { 4299 DoneList donelist; 4300 const Objlist_Entry *elm; 4301 SymLook req1; 4302 int res; 4303 4304 donelist_init(&donelist); 4305 symlook_init_from_req(&req1, req); 4306 4307 /* 4308 * Look first in the referencing object if linked symbolically, 4309 * and similarly handle protected symbols. 4310 */ 4311 res = symlook_obj(&req1, refobj); 4312 if (res == 0 && (refobj->symbolic || 4313 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4314 req->sym_out = req1.sym_out; 4315 req->defobj_out = req1.defobj_out; 4316 assert(req->defobj_out != NULL); 4317 } 4318 if (refobj->symbolic || req->defobj_out != NULL) 4319 donelist_check(&donelist, refobj); 4320 4321 symlook_global(req, &donelist); 4322 4323 /* Search all dlopened DAGs containing the referencing object. */ 4324 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4325 if (req->sym_out != NULL && 4326 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4327 break; 4328 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4329 if (res == 0 && (req->sym_out == NULL || 4330 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4331 req->sym_out = req1.sym_out; 4332 req->defobj_out = req1.defobj_out; 4333 assert(req->defobj_out != NULL); 4334 } 4335 } 4336 4337 /* 4338 * Search the dynamic linker itself, and possibly resolve the 4339 * symbol from there. This is how the application links to 4340 * dynamic linker services such as dlopen. 4341 */ 4342 if (req->sym_out == NULL || 4343 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4344 res = symlook_obj(&req1, &obj_rtld); 4345 if (res == 0) { 4346 req->sym_out = req1.sym_out; 4347 req->defobj_out = req1.defobj_out; 4348 assert(req->defobj_out != NULL); 4349 } 4350 } 4351 4352 return (req->sym_out != NULL ? 0 : ESRCH); 4353 } 4354 4355 static int 4356 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4357 { 4358 const Elf_Sym *def; 4359 const Obj_Entry *defobj; 4360 const Objlist_Entry *elm; 4361 SymLook req1; 4362 int res; 4363 4364 def = NULL; 4365 defobj = NULL; 4366 STAILQ_FOREACH(elm, objlist, link) { 4367 if (donelist_check(dlp, elm->obj)) 4368 continue; 4369 symlook_init_from_req(&req1, req); 4370 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4371 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4372 def = req1.sym_out; 4373 defobj = req1.defobj_out; 4374 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4375 break; 4376 } 4377 } 4378 } 4379 if (def != NULL) { 4380 req->sym_out = def; 4381 req->defobj_out = defobj; 4382 return (0); 4383 } 4384 return (ESRCH); 4385 } 4386 4387 /* 4388 * Search the chain of DAGS cointed to by the given Needed_Entry 4389 * for a symbol of the given name. Each DAG is scanned completely 4390 * before advancing to the next one. Returns a pointer to the symbol, 4391 * or NULL if no definition was found. 4392 */ 4393 static int 4394 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4395 { 4396 const Elf_Sym *def; 4397 const Needed_Entry *n; 4398 const Obj_Entry *defobj; 4399 SymLook req1; 4400 int res; 4401 4402 def = NULL; 4403 defobj = NULL; 4404 symlook_init_from_req(&req1, req); 4405 for (n = needed; n != NULL; n = n->next) { 4406 if (n->obj == NULL || 4407 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4408 continue; 4409 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4410 def = req1.sym_out; 4411 defobj = req1.defobj_out; 4412 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4413 break; 4414 } 4415 } 4416 if (def != NULL) { 4417 req->sym_out = def; 4418 req->defobj_out = defobj; 4419 return (0); 4420 } 4421 return (ESRCH); 4422 } 4423 4424 /* 4425 * Search the symbol table of a single shared object for a symbol of 4426 * the given name and version, if requested. Returns a pointer to the 4427 * symbol, or NULL if no definition was found. If the object is 4428 * filter, return filtered symbol from filtee. 4429 * 4430 * The symbol's hash value is passed in for efficiency reasons; that 4431 * eliminates many recomputations of the hash value. 4432 */ 4433 int 4434 symlook_obj(SymLook *req, const Obj_Entry *obj) 4435 { 4436 DoneList donelist; 4437 SymLook req1; 4438 int flags, res, mres; 4439 4440 /* 4441 * If there is at least one valid hash at this point, we prefer to 4442 * use the faster GNU version if available. 4443 */ 4444 if (obj->valid_hash_gnu) 4445 mres = symlook_obj1_gnu(req, obj); 4446 else if (obj->valid_hash_sysv) 4447 mres = symlook_obj1_sysv(req, obj); 4448 else 4449 return (EINVAL); 4450 4451 if (mres == 0) { 4452 if (obj->needed_filtees != NULL) { 4453 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4454 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4455 donelist_init(&donelist); 4456 symlook_init_from_req(&req1, req); 4457 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4458 if (res == 0) { 4459 req->sym_out = req1.sym_out; 4460 req->defobj_out = req1.defobj_out; 4461 } 4462 return (res); 4463 } 4464 if (obj->needed_aux_filtees != NULL) { 4465 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4466 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4467 donelist_init(&donelist); 4468 symlook_init_from_req(&req1, req); 4469 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4470 if (res == 0) { 4471 req->sym_out = req1.sym_out; 4472 req->defobj_out = req1.defobj_out; 4473 return (res); 4474 } 4475 } 4476 } 4477 return (mres); 4478 } 4479 4480 /* Symbol match routine common to both hash functions */ 4481 static bool 4482 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4483 const unsigned long symnum) 4484 { 4485 Elf_Versym verndx; 4486 const Elf_Sym *symp; 4487 const char *strp; 4488 4489 symp = obj->symtab + symnum; 4490 strp = obj->strtab + symp->st_name; 4491 4492 switch (ELF_ST_TYPE(symp->st_info)) { 4493 case STT_FUNC: 4494 case STT_NOTYPE: 4495 case STT_OBJECT: 4496 case STT_COMMON: 4497 case STT_GNU_IFUNC: 4498 if (symp->st_value == 0) 4499 return (false); 4500 /* fallthrough */ 4501 case STT_TLS: 4502 if (symp->st_shndx != SHN_UNDEF) 4503 break; 4504 #ifndef __mips__ 4505 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4506 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4507 break; 4508 #endif 4509 /* fallthrough */ 4510 default: 4511 return (false); 4512 } 4513 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4514 return (false); 4515 4516 if (req->ventry == NULL) { 4517 if (obj->versyms != NULL) { 4518 verndx = VER_NDX(obj->versyms[symnum]); 4519 if (verndx > obj->vernum) { 4520 _rtld_error( 4521 "%s: symbol %s references wrong version %d", 4522 obj->path, obj->strtab + symnum, verndx); 4523 return (false); 4524 } 4525 /* 4526 * If we are not called from dlsym (i.e. this 4527 * is a normal relocation from unversioned 4528 * binary), accept the symbol immediately if 4529 * it happens to have first version after this 4530 * shared object became versioned. Otherwise, 4531 * if symbol is versioned and not hidden, 4532 * remember it. If it is the only symbol with 4533 * this name exported by the shared object, it 4534 * will be returned as a match by the calling 4535 * function. If symbol is global (verndx < 2) 4536 * accept it unconditionally. 4537 */ 4538 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4539 verndx == VER_NDX_GIVEN) { 4540 result->sym_out = symp; 4541 return (true); 4542 } 4543 else if (verndx >= VER_NDX_GIVEN) { 4544 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4545 == 0) { 4546 if (result->vsymp == NULL) 4547 result->vsymp = symp; 4548 result->vcount++; 4549 } 4550 return (false); 4551 } 4552 } 4553 result->sym_out = symp; 4554 return (true); 4555 } 4556 if (obj->versyms == NULL) { 4557 if (object_match_name(obj, req->ventry->name)) { 4558 _rtld_error("%s: object %s should provide version %s " 4559 "for symbol %s", obj_rtld.path, obj->path, 4560 req->ventry->name, obj->strtab + symnum); 4561 return (false); 4562 } 4563 } else { 4564 verndx = VER_NDX(obj->versyms[symnum]); 4565 if (verndx > obj->vernum) { 4566 _rtld_error("%s: symbol %s references wrong version %d", 4567 obj->path, obj->strtab + symnum, verndx); 4568 return (false); 4569 } 4570 if (obj->vertab[verndx].hash != req->ventry->hash || 4571 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4572 /* 4573 * Version does not match. Look if this is a 4574 * global symbol and if it is not hidden. If 4575 * global symbol (verndx < 2) is available, 4576 * use it. Do not return symbol if we are 4577 * called by dlvsym, because dlvsym looks for 4578 * a specific version and default one is not 4579 * what dlvsym wants. 4580 */ 4581 if ((req->flags & SYMLOOK_DLSYM) || 4582 (verndx >= VER_NDX_GIVEN) || 4583 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4584 return (false); 4585 } 4586 } 4587 result->sym_out = symp; 4588 return (true); 4589 } 4590 4591 /* 4592 * Search for symbol using SysV hash function. 4593 * obj->buckets is known not to be NULL at this point; the test for this was 4594 * performed with the obj->valid_hash_sysv assignment. 4595 */ 4596 static int 4597 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4598 { 4599 unsigned long symnum; 4600 Sym_Match_Result matchres; 4601 4602 matchres.sym_out = NULL; 4603 matchres.vsymp = NULL; 4604 matchres.vcount = 0; 4605 4606 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4607 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4608 if (symnum >= obj->nchains) 4609 return (ESRCH); /* Bad object */ 4610 4611 if (matched_symbol(req, obj, &matchres, symnum)) { 4612 req->sym_out = matchres.sym_out; 4613 req->defobj_out = obj; 4614 return (0); 4615 } 4616 } 4617 if (matchres.vcount == 1) { 4618 req->sym_out = matchres.vsymp; 4619 req->defobj_out = obj; 4620 return (0); 4621 } 4622 return (ESRCH); 4623 } 4624 4625 /* Search for symbol using GNU hash function */ 4626 static int 4627 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4628 { 4629 Elf_Addr bloom_word; 4630 const Elf32_Word *hashval; 4631 Elf32_Word bucket; 4632 Sym_Match_Result matchres; 4633 unsigned int h1, h2; 4634 unsigned long symnum; 4635 4636 matchres.sym_out = NULL; 4637 matchres.vsymp = NULL; 4638 matchres.vcount = 0; 4639 4640 /* Pick right bitmask word from Bloom filter array */ 4641 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4642 obj->maskwords_bm_gnu]; 4643 4644 /* Calculate modulus word size of gnu hash and its derivative */ 4645 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4646 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4647 4648 /* Filter out the "definitely not in set" queries */ 4649 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4650 return (ESRCH); 4651 4652 /* Locate hash chain and corresponding value element*/ 4653 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4654 if (bucket == 0) 4655 return (ESRCH); 4656 hashval = &obj->chain_zero_gnu[bucket]; 4657 do { 4658 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4659 symnum = hashval - obj->chain_zero_gnu; 4660 if (matched_symbol(req, obj, &matchres, symnum)) { 4661 req->sym_out = matchres.sym_out; 4662 req->defobj_out = obj; 4663 return (0); 4664 } 4665 } 4666 } while ((*hashval++ & 1) == 0); 4667 if (matchres.vcount == 1) { 4668 req->sym_out = matchres.vsymp; 4669 req->defobj_out = obj; 4670 return (0); 4671 } 4672 return (ESRCH); 4673 } 4674 4675 static void 4676 trace_loaded_objects(Obj_Entry *obj) 4677 { 4678 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4679 int c; 4680 4681 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4682 main_local = ""; 4683 4684 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4685 fmt1 = "\t%o => %p (%x)\n"; 4686 4687 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4688 fmt2 = "\t%o (%x)\n"; 4689 4690 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4691 4692 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4693 Needed_Entry *needed; 4694 const char *name, *path; 4695 bool is_lib; 4696 4697 if (obj->marker) 4698 continue; 4699 if (list_containers && obj->needed != NULL) 4700 rtld_printf("%s:\n", obj->path); 4701 for (needed = obj->needed; needed; needed = needed->next) { 4702 if (needed->obj != NULL) { 4703 if (needed->obj->traced && !list_containers) 4704 continue; 4705 needed->obj->traced = true; 4706 path = needed->obj->path; 4707 } else 4708 path = "not found"; 4709 4710 name = obj->strtab + needed->name; 4711 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4712 4713 fmt = is_lib ? fmt1 : fmt2; 4714 while ((c = *fmt++) != '\0') { 4715 switch (c) { 4716 default: 4717 rtld_putchar(c); 4718 continue; 4719 case '\\': 4720 switch (c = *fmt) { 4721 case '\0': 4722 continue; 4723 case 'n': 4724 rtld_putchar('\n'); 4725 break; 4726 case 't': 4727 rtld_putchar('\t'); 4728 break; 4729 } 4730 break; 4731 case '%': 4732 switch (c = *fmt) { 4733 case '\0': 4734 continue; 4735 case '%': 4736 default: 4737 rtld_putchar(c); 4738 break; 4739 case 'A': 4740 rtld_putstr(main_local); 4741 break; 4742 case 'a': 4743 rtld_putstr(obj_main->path); 4744 break; 4745 case 'o': 4746 rtld_putstr(name); 4747 break; 4748 #if 0 4749 case 'm': 4750 rtld_printf("%d", sodp->sod_major); 4751 break; 4752 case 'n': 4753 rtld_printf("%d", sodp->sod_minor); 4754 break; 4755 #endif 4756 case 'p': 4757 rtld_putstr(path); 4758 break; 4759 case 'x': 4760 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4761 0); 4762 break; 4763 } 4764 break; 4765 } 4766 ++fmt; 4767 } 4768 } 4769 } 4770 } 4771 4772 /* 4773 * Unload a dlopened object and its dependencies from memory and from 4774 * our data structures. It is assumed that the DAG rooted in the 4775 * object has already been unreferenced, and that the object has a 4776 * reference count of 0. 4777 */ 4778 static void 4779 unload_object(Obj_Entry *root, RtldLockState *lockstate) 4780 { 4781 Obj_Entry marker, *obj, *next; 4782 4783 assert(root->refcount == 0); 4784 4785 /* 4786 * Pass over the DAG removing unreferenced objects from 4787 * appropriate lists. 4788 */ 4789 unlink_object(root); 4790 4791 /* Unmap all objects that are no longer referenced. */ 4792 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4793 next = TAILQ_NEXT(obj, next); 4794 if (obj->marker || obj->refcount != 0) 4795 continue; 4796 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4797 obj->mapsize, 0, obj->path); 4798 dbg("unloading \"%s\"", obj->path); 4799 /* 4800 * Unlink the object now to prevent new references from 4801 * being acquired while the bind lock is dropped in 4802 * recursive dlclose() invocations. 4803 */ 4804 TAILQ_REMOVE(&obj_list, obj, next); 4805 obj_count--; 4806 4807 if (obj->filtees_loaded) { 4808 if (next != NULL) { 4809 init_marker(&marker); 4810 TAILQ_INSERT_BEFORE(next, &marker, next); 4811 unload_filtees(obj, lockstate); 4812 next = TAILQ_NEXT(&marker, next); 4813 TAILQ_REMOVE(&obj_list, &marker, next); 4814 } else 4815 unload_filtees(obj, lockstate); 4816 } 4817 release_object(obj); 4818 } 4819 } 4820 4821 static void 4822 unlink_object(Obj_Entry *root) 4823 { 4824 Objlist_Entry *elm; 4825 4826 if (root->refcount == 0) { 4827 /* Remove the object from the RTLD_GLOBAL list. */ 4828 objlist_remove(&list_global, root); 4829 4830 /* Remove the object from all objects' DAG lists. */ 4831 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4832 objlist_remove(&elm->obj->dldags, root); 4833 if (elm->obj != root) 4834 unlink_object(elm->obj); 4835 } 4836 } 4837 } 4838 4839 static void 4840 ref_dag(Obj_Entry *root) 4841 { 4842 Objlist_Entry *elm; 4843 4844 assert(root->dag_inited); 4845 STAILQ_FOREACH(elm, &root->dagmembers, link) 4846 elm->obj->refcount++; 4847 } 4848 4849 static void 4850 unref_dag(Obj_Entry *root) 4851 { 4852 Objlist_Entry *elm; 4853 4854 assert(root->dag_inited); 4855 STAILQ_FOREACH(elm, &root->dagmembers, link) 4856 elm->obj->refcount--; 4857 } 4858 4859 /* 4860 * Common code for MD __tls_get_addr(). 4861 */ 4862 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4863 static void * 4864 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4865 { 4866 Elf_Addr *newdtv, *dtv; 4867 RtldLockState lockstate; 4868 int to_copy; 4869 4870 dtv = *dtvp; 4871 /* Check dtv generation in case new modules have arrived */ 4872 if (dtv[0] != tls_dtv_generation) { 4873 wlock_acquire(rtld_bind_lock, &lockstate); 4874 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4875 to_copy = dtv[1]; 4876 if (to_copy > tls_max_index) 4877 to_copy = tls_max_index; 4878 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4879 newdtv[0] = tls_dtv_generation; 4880 newdtv[1] = tls_max_index; 4881 free(dtv); 4882 lock_release(rtld_bind_lock, &lockstate); 4883 dtv = *dtvp = newdtv; 4884 } 4885 4886 /* Dynamically allocate module TLS if necessary */ 4887 if (dtv[index + 1] == 0) { 4888 /* Signal safe, wlock will block out signals. */ 4889 wlock_acquire(rtld_bind_lock, &lockstate); 4890 if (!dtv[index + 1]) 4891 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4892 lock_release(rtld_bind_lock, &lockstate); 4893 } 4894 return ((void *)(dtv[index + 1] + offset)); 4895 } 4896 4897 void * 4898 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4899 { 4900 Elf_Addr *dtv; 4901 4902 dtv = *dtvp; 4903 /* Check dtv generation in case new modules have arrived */ 4904 if (__predict_true(dtv[0] == tls_dtv_generation && 4905 dtv[index + 1] != 0)) 4906 return ((void *)(dtv[index + 1] + offset)); 4907 return (tls_get_addr_slow(dtvp, index, offset)); 4908 } 4909 4910 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4911 defined(__powerpc__) || defined(__riscv) 4912 4913 /* 4914 * Return pointer to allocated TLS block 4915 */ 4916 static void * 4917 get_tls_block_ptr(void *tcb, size_t tcbsize) 4918 { 4919 size_t extra_size, post_size, pre_size, tls_block_size; 4920 size_t tls_init_align; 4921 4922 tls_init_align = MAX(obj_main->tlsalign, 1); 4923 4924 /* Compute fragments sizes. */ 4925 extra_size = tcbsize - TLS_TCB_SIZE; 4926 post_size = calculate_tls_post_size(tls_init_align); 4927 tls_block_size = tcbsize + post_size; 4928 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4929 4930 return ((char *)tcb - pre_size - extra_size); 4931 } 4932 4933 /* 4934 * Allocate Static TLS using the Variant I method. 4935 * 4936 * For details on the layout, see lib/libc/gen/tls.c. 4937 * 4938 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as 4939 * it is based on tls_last_offset, and TLS offsets here are really TCB 4940 * offsets, whereas libc's tls_static_space is just the executable's static 4941 * TLS segment. 4942 */ 4943 void * 4944 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4945 { 4946 Obj_Entry *obj; 4947 char *tls_block; 4948 Elf_Addr *dtv, **tcb; 4949 Elf_Addr addr; 4950 Elf_Addr i; 4951 size_t extra_size, maxalign, post_size, pre_size, tls_block_size; 4952 size_t tls_init_align, tls_init_offset; 4953 4954 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4955 return (oldtcb); 4956 4957 assert(tcbsize >= TLS_TCB_SIZE); 4958 maxalign = MAX(tcbalign, tls_static_max_align); 4959 tls_init_align = MAX(obj_main->tlsalign, 1); 4960 4961 /* Compute fragmets sizes. */ 4962 extra_size = tcbsize - TLS_TCB_SIZE; 4963 post_size = calculate_tls_post_size(tls_init_align); 4964 tls_block_size = tcbsize + post_size; 4965 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; 4966 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; 4967 4968 /* Allocate whole TLS block */ 4969 tls_block = malloc_aligned(tls_block_size, maxalign, 0); 4970 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); 4971 4972 if (oldtcb != NULL) { 4973 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), 4974 tls_static_space); 4975 free_aligned(get_tls_block_ptr(oldtcb, tcbsize)); 4976 4977 /* Adjust the DTV. */ 4978 dtv = tcb[0]; 4979 for (i = 0; i < dtv[1]; i++) { 4980 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4981 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4982 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb; 4983 } 4984 } 4985 } else { 4986 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4987 tcb[0] = dtv; 4988 dtv[0] = tls_dtv_generation; 4989 dtv[1] = tls_max_index; 4990 4991 for (obj = globallist_curr(objs); obj != NULL; 4992 obj = globallist_next(obj)) { 4993 if (obj->tlsoffset == 0) 4994 continue; 4995 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); 4996 addr = (Elf_Addr)tcb + obj->tlsoffset; 4997 if (tls_init_offset > 0) 4998 memset((void *)addr, 0, tls_init_offset); 4999 if (obj->tlsinitsize > 0) { 5000 memcpy((void *)(addr + tls_init_offset), obj->tlsinit, 5001 obj->tlsinitsize); 5002 } 5003 if (obj->tlssize > obj->tlsinitsize) { 5004 memset((void *)(addr + tls_init_offset + obj->tlsinitsize), 5005 0, obj->tlssize - obj->tlsinitsize - tls_init_offset); 5006 } 5007 dtv[obj->tlsindex + 1] = addr; 5008 } 5009 } 5010 5011 return (tcb); 5012 } 5013 5014 void 5015 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) 5016 { 5017 Elf_Addr *dtv; 5018 Elf_Addr tlsstart, tlsend; 5019 size_t post_size; 5020 size_t dtvsize, i, tls_init_align; 5021 5022 assert(tcbsize >= TLS_TCB_SIZE); 5023 tls_init_align = MAX(obj_main->tlsalign, 1); 5024 5025 /* Compute fragments sizes. */ 5026 post_size = calculate_tls_post_size(tls_init_align); 5027 5028 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size; 5029 tlsend = (Elf_Addr)tcb + tls_static_space; 5030 5031 dtv = *(Elf_Addr **)tcb; 5032 dtvsize = dtv[1]; 5033 for (i = 0; i < dtvsize; i++) { 5034 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 5035 free((void*)dtv[i+2]); 5036 } 5037 } 5038 free(dtv); 5039 free_aligned(get_tls_block_ptr(tcb, tcbsize)); 5040 } 5041 5042 #endif 5043 5044 #if defined(__i386__) || defined(__amd64__) 5045 5046 /* 5047 * Allocate Static TLS using the Variant II method. 5048 */ 5049 void * 5050 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 5051 { 5052 Obj_Entry *obj; 5053 size_t size, ralign; 5054 char *tls; 5055 Elf_Addr *dtv, *olddtv; 5056 Elf_Addr segbase, oldsegbase, addr; 5057 size_t i; 5058 5059 ralign = tcbalign; 5060 if (tls_static_max_align > ralign) 5061 ralign = tls_static_max_align; 5062 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); 5063 5064 assert(tcbsize >= 2*sizeof(Elf_Addr)); 5065 tls = malloc_aligned(size, ralign, 0 /* XXX */); 5066 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 5067 5068 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign)); 5069 ((Elf_Addr*)segbase)[0] = segbase; 5070 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 5071 5072 dtv[0] = tls_dtv_generation; 5073 dtv[1] = tls_max_index; 5074 5075 if (oldtls) { 5076 /* 5077 * Copy the static TLS block over whole. 5078 */ 5079 oldsegbase = (Elf_Addr) oldtls; 5080 memcpy((void *)(segbase - tls_static_space), 5081 (const void *)(oldsegbase - tls_static_space), 5082 tls_static_space); 5083 5084 /* 5085 * If any dynamic TLS blocks have been created tls_get_addr(), 5086 * move them over. 5087 */ 5088 olddtv = ((Elf_Addr**)oldsegbase)[1]; 5089 for (i = 0; i < olddtv[1]; i++) { 5090 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 5091 dtv[i+2] = olddtv[i+2]; 5092 olddtv[i+2] = 0; 5093 } 5094 } 5095 5096 /* 5097 * We assume that this block was the one we created with 5098 * allocate_initial_tls(). 5099 */ 5100 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 5101 } else { 5102 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 5103 if (obj->marker || obj->tlsoffset == 0) 5104 continue; 5105 addr = segbase - obj->tlsoffset; 5106 memset((void*)(addr + obj->tlsinitsize), 5107 0, obj->tlssize - obj->tlsinitsize); 5108 if (obj->tlsinit) { 5109 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 5110 obj->static_tls_copied = true; 5111 } 5112 dtv[obj->tlsindex + 1] = addr; 5113 } 5114 } 5115 5116 return (void*) segbase; 5117 } 5118 5119 void 5120 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign) 5121 { 5122 Elf_Addr* dtv; 5123 size_t size, ralign; 5124 int dtvsize, i; 5125 Elf_Addr tlsstart, tlsend; 5126 5127 /* 5128 * Figure out the size of the initial TLS block so that we can 5129 * find stuff which ___tls_get_addr() allocated dynamically. 5130 */ 5131 ralign = tcbalign; 5132 if (tls_static_max_align > ralign) 5133 ralign = tls_static_max_align; 5134 size = roundup(tls_static_space, ralign); 5135 5136 dtv = ((Elf_Addr**)tls)[1]; 5137 dtvsize = dtv[1]; 5138 tlsend = (Elf_Addr) tls; 5139 tlsstart = tlsend - size; 5140 for (i = 0; i < dtvsize; i++) { 5141 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 5142 free_aligned((void *)dtv[i + 2]); 5143 } 5144 } 5145 5146 free_aligned((void *)tlsstart); 5147 free((void*) dtv); 5148 } 5149 5150 #endif 5151 5152 /* 5153 * Allocate TLS block for module with given index. 5154 */ 5155 void * 5156 allocate_module_tls(int index) 5157 { 5158 Obj_Entry *obj; 5159 char *p; 5160 5161 TAILQ_FOREACH(obj, &obj_list, next) { 5162 if (obj->marker) 5163 continue; 5164 if (obj->tlsindex == index) 5165 break; 5166 } 5167 if (obj == NULL) { 5168 _rtld_error("Can't find module with TLS index %d", index); 5169 rtld_die(); 5170 } 5171 5172 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); 5173 memcpy(p, obj->tlsinit, obj->tlsinitsize); 5174 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 5175 return (p); 5176 } 5177 5178 bool 5179 allocate_tls_offset(Obj_Entry *obj) 5180 { 5181 size_t off; 5182 5183 if (obj->tls_done) 5184 return true; 5185 5186 if (obj->tlssize == 0) { 5187 obj->tls_done = true; 5188 return true; 5189 } 5190 5191 if (tls_last_offset == 0) 5192 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign, 5193 obj->tlspoffset); 5194 else 5195 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5196 obj->tlssize, obj->tlsalign, obj->tlspoffset); 5197 5198 /* 5199 * If we have already fixed the size of the static TLS block, we 5200 * must stay within that size. When allocating the static TLS, we 5201 * leave a small amount of space spare to be used for dynamically 5202 * loading modules which use static TLS. 5203 */ 5204 if (tls_static_space != 0) { 5205 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5206 return false; 5207 } else if (obj->tlsalign > tls_static_max_align) { 5208 tls_static_max_align = obj->tlsalign; 5209 } 5210 5211 tls_last_offset = obj->tlsoffset = off; 5212 tls_last_size = obj->tlssize; 5213 obj->tls_done = true; 5214 5215 return true; 5216 } 5217 5218 void 5219 free_tls_offset(Obj_Entry *obj) 5220 { 5221 5222 /* 5223 * If we were the last thing to allocate out of the static TLS 5224 * block, we give our space back to the 'allocator'. This is a 5225 * simplistic workaround to allow libGL.so.1 to be loaded and 5226 * unloaded multiple times. 5227 */ 5228 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5229 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5230 tls_last_offset -= obj->tlssize; 5231 tls_last_size = 0; 5232 } 5233 } 5234 5235 void * 5236 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5237 { 5238 void *ret; 5239 RtldLockState lockstate; 5240 5241 wlock_acquire(rtld_bind_lock, &lockstate); 5242 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5243 tcbsize, tcbalign); 5244 lock_release(rtld_bind_lock, &lockstate); 5245 return (ret); 5246 } 5247 5248 void 5249 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5250 { 5251 RtldLockState lockstate; 5252 5253 wlock_acquire(rtld_bind_lock, &lockstate); 5254 free_tls(tcb, tcbsize, tcbalign); 5255 lock_release(rtld_bind_lock, &lockstate); 5256 } 5257 5258 static void 5259 object_add_name(Obj_Entry *obj, const char *name) 5260 { 5261 Name_Entry *entry; 5262 size_t len; 5263 5264 len = strlen(name); 5265 entry = malloc(sizeof(Name_Entry) + len); 5266 5267 if (entry != NULL) { 5268 strcpy(entry->name, name); 5269 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5270 } 5271 } 5272 5273 static int 5274 object_match_name(const Obj_Entry *obj, const char *name) 5275 { 5276 Name_Entry *entry; 5277 5278 STAILQ_FOREACH(entry, &obj->names, link) { 5279 if (strcmp(name, entry->name) == 0) 5280 return (1); 5281 } 5282 return (0); 5283 } 5284 5285 static Obj_Entry * 5286 locate_dependency(const Obj_Entry *obj, const char *name) 5287 { 5288 const Objlist_Entry *entry; 5289 const Needed_Entry *needed; 5290 5291 STAILQ_FOREACH(entry, &list_main, link) { 5292 if (object_match_name(entry->obj, name)) 5293 return entry->obj; 5294 } 5295 5296 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5297 if (strcmp(obj->strtab + needed->name, name) == 0 || 5298 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5299 /* 5300 * If there is DT_NEEDED for the name we are looking for, 5301 * we are all set. Note that object might not be found if 5302 * dependency was not loaded yet, so the function can 5303 * return NULL here. This is expected and handled 5304 * properly by the caller. 5305 */ 5306 return (needed->obj); 5307 } 5308 } 5309 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5310 obj->path, name); 5311 rtld_die(); 5312 } 5313 5314 static int 5315 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5316 const Elf_Vernaux *vna) 5317 { 5318 const Elf_Verdef *vd; 5319 const char *vername; 5320 5321 vername = refobj->strtab + vna->vna_name; 5322 vd = depobj->verdef; 5323 if (vd == NULL) { 5324 _rtld_error("%s: version %s required by %s not defined", 5325 depobj->path, vername, refobj->path); 5326 return (-1); 5327 } 5328 for (;;) { 5329 if (vd->vd_version != VER_DEF_CURRENT) { 5330 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5331 depobj->path, vd->vd_version); 5332 return (-1); 5333 } 5334 if (vna->vna_hash == vd->vd_hash) { 5335 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5336 ((const char *)vd + vd->vd_aux); 5337 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5338 return (0); 5339 } 5340 if (vd->vd_next == 0) 5341 break; 5342 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5343 } 5344 if (vna->vna_flags & VER_FLG_WEAK) 5345 return (0); 5346 _rtld_error("%s: version %s required by %s not found", 5347 depobj->path, vername, refobj->path); 5348 return (-1); 5349 } 5350 5351 static int 5352 rtld_verify_object_versions(Obj_Entry *obj) 5353 { 5354 const Elf_Verneed *vn; 5355 const Elf_Verdef *vd; 5356 const Elf_Verdaux *vda; 5357 const Elf_Vernaux *vna; 5358 const Obj_Entry *depobj; 5359 int maxvernum, vernum; 5360 5361 if (obj->ver_checked) 5362 return (0); 5363 obj->ver_checked = true; 5364 5365 maxvernum = 0; 5366 /* 5367 * Walk over defined and required version records and figure out 5368 * max index used by any of them. Do very basic sanity checking 5369 * while there. 5370 */ 5371 vn = obj->verneed; 5372 while (vn != NULL) { 5373 if (vn->vn_version != VER_NEED_CURRENT) { 5374 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5375 obj->path, vn->vn_version); 5376 return (-1); 5377 } 5378 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5379 for (;;) { 5380 vernum = VER_NEED_IDX(vna->vna_other); 5381 if (vernum > maxvernum) 5382 maxvernum = vernum; 5383 if (vna->vna_next == 0) 5384 break; 5385 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5386 } 5387 if (vn->vn_next == 0) 5388 break; 5389 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5390 } 5391 5392 vd = obj->verdef; 5393 while (vd != NULL) { 5394 if (vd->vd_version != VER_DEF_CURRENT) { 5395 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5396 obj->path, vd->vd_version); 5397 return (-1); 5398 } 5399 vernum = VER_DEF_IDX(vd->vd_ndx); 5400 if (vernum > maxvernum) 5401 maxvernum = vernum; 5402 if (vd->vd_next == 0) 5403 break; 5404 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5405 } 5406 5407 if (maxvernum == 0) 5408 return (0); 5409 5410 /* 5411 * Store version information in array indexable by version index. 5412 * Verify that object version requirements are satisfied along the 5413 * way. 5414 */ 5415 obj->vernum = maxvernum + 1; 5416 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5417 5418 vd = obj->verdef; 5419 while (vd != NULL) { 5420 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5421 vernum = VER_DEF_IDX(vd->vd_ndx); 5422 assert(vernum <= maxvernum); 5423 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); 5424 obj->vertab[vernum].hash = vd->vd_hash; 5425 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5426 obj->vertab[vernum].file = NULL; 5427 obj->vertab[vernum].flags = 0; 5428 } 5429 if (vd->vd_next == 0) 5430 break; 5431 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); 5432 } 5433 5434 vn = obj->verneed; 5435 while (vn != NULL) { 5436 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5437 if (depobj == NULL) 5438 return (-1); 5439 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); 5440 for (;;) { 5441 if (check_object_provided_version(obj, depobj, vna)) 5442 return (-1); 5443 vernum = VER_NEED_IDX(vna->vna_other); 5444 assert(vernum <= maxvernum); 5445 obj->vertab[vernum].hash = vna->vna_hash; 5446 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5447 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5448 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5449 VER_INFO_HIDDEN : 0; 5450 if (vna->vna_next == 0) 5451 break; 5452 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); 5453 } 5454 if (vn->vn_next == 0) 5455 break; 5456 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); 5457 } 5458 return 0; 5459 } 5460 5461 static int 5462 rtld_verify_versions(const Objlist *objlist) 5463 { 5464 Objlist_Entry *entry; 5465 int rc; 5466 5467 rc = 0; 5468 STAILQ_FOREACH(entry, objlist, link) { 5469 /* 5470 * Skip dummy objects or objects that have their version requirements 5471 * already checked. 5472 */ 5473 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5474 continue; 5475 if (rtld_verify_object_versions(entry->obj) == -1) { 5476 rc = -1; 5477 if (ld_tracing == NULL) 5478 break; 5479 } 5480 } 5481 if (rc == 0 || ld_tracing != NULL) 5482 rc = rtld_verify_object_versions(&obj_rtld); 5483 return rc; 5484 } 5485 5486 const Ver_Entry * 5487 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5488 { 5489 Elf_Versym vernum; 5490 5491 if (obj->vertab) { 5492 vernum = VER_NDX(obj->versyms[symnum]); 5493 if (vernum >= obj->vernum) { 5494 _rtld_error("%s: symbol %s has wrong verneed value %d", 5495 obj->path, obj->strtab + symnum, vernum); 5496 } else if (obj->vertab[vernum].hash != 0) { 5497 return &obj->vertab[vernum]; 5498 } 5499 } 5500 return NULL; 5501 } 5502 5503 int 5504 _rtld_get_stack_prot(void) 5505 { 5506 5507 return (stack_prot); 5508 } 5509 5510 int 5511 _rtld_is_dlopened(void *arg) 5512 { 5513 Obj_Entry *obj; 5514 RtldLockState lockstate; 5515 int res; 5516 5517 rlock_acquire(rtld_bind_lock, &lockstate); 5518 obj = dlcheck(arg); 5519 if (obj == NULL) 5520 obj = obj_from_addr(arg); 5521 if (obj == NULL) { 5522 _rtld_error("No shared object contains address"); 5523 lock_release(rtld_bind_lock, &lockstate); 5524 return (-1); 5525 } 5526 res = obj->dlopened ? 1 : 0; 5527 lock_release(rtld_bind_lock, &lockstate); 5528 return (res); 5529 } 5530 5531 static int 5532 obj_remap_relro(Obj_Entry *obj, int prot) 5533 { 5534 5535 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5536 prot) == -1) { 5537 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5538 obj->path, prot, rtld_strerror(errno)); 5539 return (-1); 5540 } 5541 return (0); 5542 } 5543 5544 static int 5545 obj_disable_relro(Obj_Entry *obj) 5546 { 5547 5548 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5549 } 5550 5551 static int 5552 obj_enforce_relro(Obj_Entry *obj) 5553 { 5554 5555 return (obj_remap_relro(obj, PROT_READ)); 5556 } 5557 5558 static void 5559 map_stacks_exec(RtldLockState *lockstate) 5560 { 5561 void (*thr_map_stacks_exec)(void); 5562 5563 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5564 return; 5565 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5566 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5567 if (thr_map_stacks_exec != NULL) { 5568 stack_prot |= PROT_EXEC; 5569 thr_map_stacks_exec(); 5570 } 5571 } 5572 5573 static void 5574 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5575 { 5576 Objlist_Entry *elm; 5577 Obj_Entry *obj; 5578 void (*distrib)(size_t, void *, size_t, size_t); 5579 5580 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5581 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5582 if (distrib == NULL) 5583 return; 5584 STAILQ_FOREACH(elm, list, link) { 5585 obj = elm->obj; 5586 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5587 continue; 5588 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5589 obj->tlssize); 5590 obj->static_tls_copied = true; 5591 } 5592 } 5593 5594 void 5595 symlook_init(SymLook *dst, const char *name) 5596 { 5597 5598 bzero(dst, sizeof(*dst)); 5599 dst->name = name; 5600 dst->hash = elf_hash(name); 5601 dst->hash_gnu = gnu_hash(name); 5602 } 5603 5604 static void 5605 symlook_init_from_req(SymLook *dst, const SymLook *src) 5606 { 5607 5608 dst->name = src->name; 5609 dst->hash = src->hash; 5610 dst->hash_gnu = src->hash_gnu; 5611 dst->ventry = src->ventry; 5612 dst->flags = src->flags; 5613 dst->defobj_out = NULL; 5614 dst->sym_out = NULL; 5615 dst->lockstate = src->lockstate; 5616 } 5617 5618 static int 5619 open_binary_fd(const char *argv0, bool search_in_path, 5620 const char **binpath_res) 5621 { 5622 char *binpath, *pathenv, *pe, *res1; 5623 const char *res; 5624 int fd; 5625 5626 binpath = NULL; 5627 res = NULL; 5628 if (search_in_path && strchr(argv0, '/') == NULL) { 5629 binpath = xmalloc(PATH_MAX); 5630 pathenv = getenv("PATH"); 5631 if (pathenv == NULL) { 5632 _rtld_error("-p and no PATH environment variable"); 5633 rtld_die(); 5634 } 5635 pathenv = strdup(pathenv); 5636 if (pathenv == NULL) { 5637 _rtld_error("Cannot allocate memory"); 5638 rtld_die(); 5639 } 5640 fd = -1; 5641 errno = ENOENT; 5642 while ((pe = strsep(&pathenv, ":")) != NULL) { 5643 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5644 continue; 5645 if (binpath[0] != '\0' && 5646 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5647 continue; 5648 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5649 continue; 5650 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5651 if (fd != -1 || errno != ENOENT) { 5652 res = binpath; 5653 break; 5654 } 5655 } 5656 free(pathenv); 5657 } else { 5658 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5659 res = argv0; 5660 } 5661 5662 if (fd == -1) { 5663 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); 5664 rtld_die(); 5665 } 5666 if (res != NULL && res[0] != '/') { 5667 res1 = xmalloc(PATH_MAX); 5668 if (realpath(res, res1) != NULL) { 5669 if (res != argv0) 5670 free(__DECONST(char *, res)); 5671 res = res1; 5672 } else { 5673 free(res1); 5674 } 5675 } 5676 *binpath_res = res; 5677 return (fd); 5678 } 5679 5680 /* 5681 * Parse a set of command-line arguments. 5682 */ 5683 static int 5684 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp, 5685 const char **argv0) 5686 { 5687 const char *arg; 5688 char machine[64]; 5689 size_t sz; 5690 int arglen, fd, i, j, mib[2]; 5691 char opt; 5692 bool seen_b, seen_f; 5693 5694 dbg("Parsing command-line arguments"); 5695 *use_pathp = false; 5696 *fdp = -1; 5697 seen_b = seen_f = false; 5698 5699 for (i = 1; i < argc; i++ ) { 5700 arg = argv[i]; 5701 dbg("argv[%d]: '%s'", i, arg); 5702 5703 /* 5704 * rtld arguments end with an explicit "--" or with the first 5705 * non-prefixed argument. 5706 */ 5707 if (strcmp(arg, "--") == 0) { 5708 i++; 5709 break; 5710 } 5711 if (arg[0] != '-') 5712 break; 5713 5714 /* 5715 * All other arguments are single-character options that can 5716 * be combined, so we need to search through `arg` for them. 5717 */ 5718 arglen = strlen(arg); 5719 for (j = 1; j < arglen; j++) { 5720 opt = arg[j]; 5721 if (opt == 'h') { 5722 print_usage(argv[0]); 5723 _exit(0); 5724 } else if (opt == 'b') { 5725 if (seen_f) { 5726 _rtld_error("Both -b and -f specified"); 5727 rtld_die(); 5728 } 5729 i++; 5730 *argv0 = argv[i]; 5731 seen_b = true; 5732 break; 5733 } else if (opt == 'f') { 5734 if (seen_b) { 5735 _rtld_error("Both -b and -f specified"); 5736 rtld_die(); 5737 } 5738 5739 /* 5740 * -f XX can be used to specify a 5741 * descriptor for the binary named at 5742 * the command line (i.e., the later 5743 * argument will specify the process 5744 * name but the descriptor is what 5745 * will actually be executed). 5746 * 5747 * -f must be the last option in, e.g., -abcf. 5748 */ 5749 if (j != arglen - 1) { 5750 _rtld_error("Invalid options: %s", arg); 5751 rtld_die(); 5752 } 5753 i++; 5754 fd = parse_integer(argv[i]); 5755 if (fd == -1) { 5756 _rtld_error( 5757 "Invalid file descriptor: '%s'", 5758 argv[i]); 5759 rtld_die(); 5760 } 5761 *fdp = fd; 5762 seen_f = true; 5763 break; 5764 } else if (opt == 'p') { 5765 *use_pathp = true; 5766 } else if (opt == 'v') { 5767 machine[0] = '\0'; 5768 mib[0] = CTL_HW; 5769 mib[1] = HW_MACHINE; 5770 sz = sizeof(machine); 5771 sysctl(mib, nitems(mib), machine, &sz, NULL, 0); 5772 rtld_printf( 5773 "FreeBSD ld-elf.so.1 %s\n" 5774 "FreeBSD_version %d\n" 5775 "Default lib path %s\n" 5776 "Env prefix %s\n" 5777 "Hint file %s\n" 5778 "libmap file %s\n", 5779 machine, 5780 __FreeBSD_version, ld_standard_library_path, 5781 ld_env_prefix, ld_elf_hints_default, 5782 ld_path_libmap_conf); 5783 _exit(0); 5784 } else { 5785 _rtld_error("Invalid argument: '%s'", arg); 5786 print_usage(argv[0]); 5787 rtld_die(); 5788 } 5789 } 5790 } 5791 5792 if (!seen_b) 5793 *argv0 = argv[i]; 5794 return (i); 5795 } 5796 5797 /* 5798 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5799 */ 5800 static int 5801 parse_integer(const char *str) 5802 { 5803 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5804 const char *orig; 5805 int n; 5806 char c; 5807 5808 orig = str; 5809 n = 0; 5810 for (c = *str; c != '\0'; c = *++str) { 5811 if (c < '0' || c > '9') 5812 return (-1); 5813 5814 n *= RADIX; 5815 n += c - '0'; 5816 } 5817 5818 /* Make sure we actually parsed something. */ 5819 if (str == orig) 5820 return (-1); 5821 return (n); 5822 } 5823 5824 static void 5825 print_usage(const char *argv0) 5826 { 5827 5828 rtld_printf( 5829 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n" 5830 "\n" 5831 "Options:\n" 5832 " -h Display this help message\n" 5833 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n" 5834 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5835 " -p Search in PATH for named binary\n" 5836 " -v Display identification information\n" 5837 " -- End of RTLD options\n" 5838 " <binary> Name of process to execute\n" 5839 " <args> Arguments to the executed process\n", argv0); 5840 } 5841 5842 /* 5843 * Overrides for libc_pic-provided functions. 5844 */ 5845 5846 int 5847 __getosreldate(void) 5848 { 5849 size_t len; 5850 int oid[2]; 5851 int error, osrel; 5852 5853 if (osreldate != 0) 5854 return (osreldate); 5855 5856 oid[0] = CTL_KERN; 5857 oid[1] = KERN_OSRELDATE; 5858 osrel = 0; 5859 len = sizeof(osrel); 5860 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5861 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5862 osreldate = osrel; 5863 return (osreldate); 5864 } 5865 const char * 5866 rtld_strerror(int errnum) 5867 { 5868 5869 if (errnum < 0 || errnum >= sys_nerr) 5870 return ("Unknown error"); 5871 return (sys_errlist[errnum]); 5872 } 5873 5874 /* malloc */ 5875 void * 5876 malloc(size_t nbytes) 5877 { 5878 5879 return (__crt_malloc(nbytes)); 5880 } 5881 5882 void * 5883 calloc(size_t num, size_t size) 5884 { 5885 5886 return (__crt_calloc(num, size)); 5887 } 5888 5889 void 5890 free(void *cp) 5891 { 5892 5893 __crt_free(cp); 5894 } 5895 5896 void * 5897 realloc(void *cp, size_t nbytes) 5898 { 5899 5900 return (__crt_realloc(cp, nbytes)); 5901 } 5902 5903 extern int _rtld_version__FreeBSD_version __exported; 5904 int _rtld_version__FreeBSD_version = __FreeBSD_version; 5905 5906 extern char _rtld_version_laddr_offset __exported; 5907 char _rtld_version_laddr_offset; 5908