rtld.c revision 346156
1/*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * Copyright 2014-2017 The FreeBSD Foundation 7 * All rights reserved. 8 * 9 * Portions of this software were developed by Konstantin Belousov 10 * under sponsorship from the FreeBSD Foundation. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33/* 34 * Dynamic linker for ELF. 35 * 36 * John Polstra <jdp@polstra.com>. 37 */ 38 39#include <sys/cdefs.h> 40__FBSDID("$FreeBSD: stable/11/libexec/rtld-elf/rtld.c 346156 2019-04-12 15:15:27Z kib $"); 41 42#include <sys/param.h> 43#include <sys/mount.h> 44#include <sys/mman.h> 45#include <sys/stat.h> 46#include <sys/sysctl.h> 47#include <sys/uio.h> 48#include <sys/utsname.h> 49#include <sys/ktrace.h> 50 51#include <dlfcn.h> 52#include <err.h> 53#include <errno.h> 54#include <fcntl.h> 55#include <stdarg.h> 56#include <stdio.h> 57#include <stdlib.h> 58#include <string.h> 59#include <unistd.h> 60 61#include "debug.h" 62#include "rtld.h" 63#include "libmap.h" 64#include "paths.h" 65#include "rtld_tls.h" 66#include "rtld_printf.h" 67#include "rtld_utrace.h" 68#include "notes.h" 69 70/* Types. */ 71typedef void (*func_ptr_type)(); 72typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 73 74/* 75 * Function declarations. 76 */ 77static const char *basename(const char *); 78static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 79 const Elf_Dyn **, const Elf_Dyn **); 80static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 81 const Elf_Dyn *); 82static void digest_dynamic(Obj_Entry *, int); 83static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 84static void distribute_static_tls(Objlist *, RtldLockState *); 85static Obj_Entry *dlcheck(void *); 86static int dlclose_locked(void *, RtldLockState *); 87static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 88 int lo_flags, int mode, RtldLockState *lockstate); 89static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 90static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 91static bool donelist_check(DoneList *, const Obj_Entry *); 92static void errmsg_restore(char *); 93static char *errmsg_save(void); 94static void *fill_search_info(const char *, size_t, void *); 95static char *find_library(const char *, const Obj_Entry *, int *); 96static const char *gethints(bool); 97static void hold_object(Obj_Entry *); 98static void unhold_object(Obj_Entry *); 99static void init_dag(Obj_Entry *); 100static void init_marker(Obj_Entry *); 101static void init_pagesizes(Elf_Auxinfo **aux_info); 102static void init_rtld(caddr_t, Elf_Auxinfo **); 103static void initlist_add_neededs(Needed_Entry *, Objlist *); 104static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 105static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 106static void linkmap_add(Obj_Entry *); 107static void linkmap_delete(Obj_Entry *); 108static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 109static void unload_filtees(Obj_Entry *, RtldLockState *); 110static int load_needed_objects(Obj_Entry *, int); 111static int load_preload_objects(void); 112static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 113static void map_stacks_exec(RtldLockState *); 114static int obj_disable_relro(Obj_Entry *); 115static int obj_enforce_relro(Obj_Entry *); 116static Obj_Entry *obj_from_addr(const void *); 117static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 118static void objlist_call_init(Objlist *, RtldLockState *); 119static void objlist_clear(Objlist *); 120static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 121static void objlist_init(Objlist *); 122static void objlist_push_head(Objlist *, Obj_Entry *); 123static void objlist_push_tail(Objlist *, Obj_Entry *); 124static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 125static void objlist_remove(Objlist *, Obj_Entry *); 126static int open_binary_fd(const char *argv0, bool search_in_path); 127static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 128static int parse_integer(const char *); 129static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 130static void print_usage(const char *argv0); 131static void release_object(Obj_Entry *); 132static int relocate_object_dag(Obj_Entry *root, bool bind_now, 133 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 134static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 135 int flags, RtldLockState *lockstate); 136static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 137 RtldLockState *); 138static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 139static int rtld_dirname(const char *, char *); 140static int rtld_dirname_abs(const char *, char *); 141static void *rtld_dlopen(const char *name, int fd, int mode); 142static void rtld_exit(void); 143static char *search_library_path(const char *, const char *, const char *, 144 int *); 145static char *search_library_pathfds(const char *, const char *, int *); 146static const void **get_program_var_addr(const char *, RtldLockState *); 147static void set_program_var(const char *, const void *); 148static int symlook_default(SymLook *, const Obj_Entry *refobj); 149static int symlook_global(SymLook *, DoneList *); 150static void symlook_init_from_req(SymLook *, const SymLook *); 151static int symlook_list(SymLook *, const Objlist *, DoneList *); 152static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 153static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 154static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 155static void trace_loaded_objects(Obj_Entry *); 156static void unlink_object(Obj_Entry *); 157static void unload_object(Obj_Entry *, RtldLockState *lockstate); 158static void unref_dag(Obj_Entry *); 159static void ref_dag(Obj_Entry *); 160static char *origin_subst_one(Obj_Entry *, char *, const char *, 161 const char *, bool); 162static char *origin_subst(Obj_Entry *, char *); 163static bool obj_resolve_origin(Obj_Entry *obj); 164static void preinit_main(void); 165static int rtld_verify_versions(const Objlist *); 166static int rtld_verify_object_versions(Obj_Entry *); 167static void object_add_name(Obj_Entry *, const char *); 168static int object_match_name(const Obj_Entry *, const char *); 169static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 170static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 171 struct dl_phdr_info *phdr_info); 172static uint32_t gnu_hash(const char *); 173static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 174 const unsigned long); 175 176void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 177void _r_debug_postinit(struct link_map *) __noinline __exported; 178 179int __sys_openat(int, const char *, int, ...); 180 181/* 182 * Data declarations. 183 */ 184static char *error_message; /* Message for dlerror(), or NULL */ 185struct r_debug r_debug __exported; /* for GDB; */ 186static bool libmap_disable; /* Disable libmap */ 187static bool ld_loadfltr; /* Immediate filters processing */ 188static char *libmap_override; /* Maps to use in addition to libmap.conf */ 189static bool trust; /* False for setuid and setgid programs */ 190static bool dangerous_ld_env; /* True if environment variables have been 191 used to affect the libraries loaded */ 192bool ld_bind_not; /* Disable PLT update */ 193static char *ld_bind_now; /* Environment variable for immediate binding */ 194static char *ld_debug; /* Environment variable for debugging */ 195static char *ld_library_path; /* Environment variable for search path */ 196static char *ld_library_dirs; /* Environment variable for library descriptors */ 197static char *ld_preload; /* Environment variable for libraries to 198 load first */ 199static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 200static char *ld_tracing; /* Called from ldd to print libs */ 201static char *ld_utrace; /* Use utrace() to log events. */ 202static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 203static Obj_Entry *obj_main; /* The main program shared object */ 204static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 205static unsigned int obj_count; /* Number of objects in obj_list */ 206static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 207 208static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 209 STAILQ_HEAD_INITIALIZER(list_global); 210static Objlist list_main = /* Objects loaded at program startup */ 211 STAILQ_HEAD_INITIALIZER(list_main); 212static Objlist list_fini = /* Objects needing fini() calls */ 213 STAILQ_HEAD_INITIALIZER(list_fini); 214 215Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 216 217#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 218 219extern Elf_Dyn _DYNAMIC; 220#pragma weak _DYNAMIC 221 222int dlclose(void *) __exported; 223char *dlerror(void) __exported; 224void *dlopen(const char *, int) __exported; 225void *fdlopen(int, int) __exported; 226void *dlsym(void *, const char *) __exported; 227dlfunc_t dlfunc(void *, const char *) __exported; 228void *dlvsym(void *, const char *, const char *) __exported; 229int dladdr(const void *, Dl_info *) __exported; 230void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 231 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 232int dlinfo(void *, int , void *) __exported; 233int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 234int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 235int _rtld_get_stack_prot(void) __exported; 236int _rtld_is_dlopened(void *) __exported; 237void _rtld_error(const char *, ...) __exported; 238 239int npagesizes, osreldate; 240size_t *pagesizes; 241 242long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 243 244static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 245static int max_stack_flags; 246 247/* 248 * Global declarations normally provided by crt1. The dynamic linker is 249 * not built with crt1, so we have to provide them ourselves. 250 */ 251char *__progname; 252char **environ; 253 254/* 255 * Used to pass argc, argv to init functions. 256 */ 257int main_argc; 258char **main_argv; 259 260/* 261 * Globals to control TLS allocation. 262 */ 263size_t tls_last_offset; /* Static TLS offset of last module */ 264size_t tls_last_size; /* Static TLS size of last module */ 265size_t tls_static_space; /* Static TLS space allocated */ 266size_t tls_static_max_align; 267int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 268int tls_max_index = 1; /* Largest module index allocated */ 269 270bool ld_library_path_rpath = false; 271 272/* 273 * Globals for path names, and such 274 */ 275char *ld_elf_hints_default = _PATH_ELF_HINTS; 276char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 277char *ld_path_rtld = _PATH_RTLD; 278char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 279char *ld_env_prefix = LD_; 280 281/* 282 * Fill in a DoneList with an allocation large enough to hold all of 283 * the currently-loaded objects. Keep this as a macro since it calls 284 * alloca and we want that to occur within the scope of the caller. 285 */ 286#define donelist_init(dlp) \ 287 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 288 assert((dlp)->objs != NULL), \ 289 (dlp)->num_alloc = obj_count, \ 290 (dlp)->num_used = 0) 291 292#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 293 if (ld_utrace != NULL) \ 294 ld_utrace_log(e, h, mb, ms, r, n); \ 295} while (0) 296 297static void 298ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 299 int refcnt, const char *name) 300{ 301 struct utrace_rtld ut; 302 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 303 304 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 305 ut.event = event; 306 ut.handle = handle; 307 ut.mapbase = mapbase; 308 ut.mapsize = mapsize; 309 ut.refcnt = refcnt; 310 bzero(ut.name, sizeof(ut.name)); 311 if (name) 312 strlcpy(ut.name, name, sizeof(ut.name)); 313 utrace(&ut, sizeof(ut)); 314} 315 316#ifdef RTLD_VARIANT_ENV_NAMES 317/* 318 * construct the env variable based on the type of binary that's 319 * running. 320 */ 321static inline const char * 322_LD(const char *var) 323{ 324 static char buffer[128]; 325 326 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 327 strlcat(buffer, var, sizeof(buffer)); 328 return (buffer); 329} 330#else 331#define _LD(x) LD_ x 332#endif 333 334/* 335 * Main entry point for dynamic linking. The first argument is the 336 * stack pointer. The stack is expected to be laid out as described 337 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 338 * Specifically, the stack pointer points to a word containing 339 * ARGC. Following that in the stack is a null-terminated sequence 340 * of pointers to argument strings. Then comes a null-terminated 341 * sequence of pointers to environment strings. Finally, there is a 342 * sequence of "auxiliary vector" entries. 343 * 344 * The second argument points to a place to store the dynamic linker's 345 * exit procedure pointer and the third to a place to store the main 346 * program's object. 347 * 348 * The return value is the main program's entry point. 349 */ 350func_ptr_type 351_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 352{ 353 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 354 Objlist_Entry *entry; 355 Obj_Entry *last_interposer, *obj, *preload_tail; 356 const Elf_Phdr *phdr; 357 Objlist initlist; 358 RtldLockState lockstate; 359 struct stat st; 360 Elf_Addr *argcp; 361 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 362 caddr_t imgentry; 363 char buf[MAXPATHLEN]; 364 int argc, fd, i, mib[2], phnum, rtld_argc; 365 size_t len; 366 bool dir_enable, explicit_fd, search_in_path; 367 368 /* 369 * On entry, the dynamic linker itself has not been relocated yet. 370 * Be very careful not to reference any global data until after 371 * init_rtld has returned. It is OK to reference file-scope statics 372 * and string constants, and to call static and global functions. 373 */ 374 375 /* Find the auxiliary vector on the stack. */ 376 argcp = sp; 377 argc = *sp++; 378 argv = (char **) sp; 379 sp += argc + 1; /* Skip over arguments and NULL terminator */ 380 env = (char **) sp; 381 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 382 ; 383 aux = (Elf_Auxinfo *) sp; 384 385 /* Digest the auxiliary vector. */ 386 for (i = 0; i < AT_COUNT; i++) 387 aux_info[i] = NULL; 388 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 389 if (auxp->a_type < AT_COUNT) 390 aux_info[auxp->a_type] = auxp; 391 } 392 393 /* Initialize and relocate ourselves. */ 394 assert(aux_info[AT_BASE] != NULL); 395 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 396 397 __progname = obj_rtld.path; 398 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 399 environ = env; 400 main_argc = argc; 401 main_argv = argv; 402 403 if (aux_info[AT_CANARY] != NULL && 404 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 405 i = aux_info[AT_CANARYLEN]->a_un.a_val; 406 if (i > sizeof(__stack_chk_guard)) 407 i = sizeof(__stack_chk_guard); 408 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 409 } else { 410 mib[0] = CTL_KERN; 411 mib[1] = KERN_ARND; 412 413 len = sizeof(__stack_chk_guard); 414 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 415 len != sizeof(__stack_chk_guard)) { 416 /* If sysctl was unsuccessful, use the "terminator canary". */ 417 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 418 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 419 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 420 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 421 } 422 } 423 424 trust = !issetugid(); 425 426 md_abi_variant_hook(aux_info); 427 428 fd = -1; 429 if (aux_info[AT_EXECFD] != NULL) { 430 fd = aux_info[AT_EXECFD]->a_un.a_val; 431 } else { 432 assert(aux_info[AT_PHDR] != NULL); 433 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 434 if (phdr == obj_rtld.phdr) { 435 if (!trust) { 436 rtld_printf("Tainted process refusing to run binary %s\n", 437 argv0); 438 rtld_die(); 439 } 440 dbg("opening main program in direct exec mode"); 441 if (argc >= 2) { 442 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 443 argv0 = argv[rtld_argc]; 444 explicit_fd = (fd != -1); 445 if (!explicit_fd) 446 fd = open_binary_fd(argv0, search_in_path); 447 if (fstat(fd, &st) == -1) { 448 _rtld_error("failed to fstat FD %d (%s): %s", fd, 449 explicit_fd ? "user-provided descriptor" : argv0, 450 rtld_strerror(errno)); 451 rtld_die(); 452 } 453 454 /* 455 * Rough emulation of the permission checks done by 456 * execve(2), only Unix DACs are checked, ACLs are 457 * ignored. Preserve the semantic of disabling owner 458 * to execute if owner x bit is cleared, even if 459 * others x bit is enabled. 460 * mmap(2) does not allow to mmap with PROT_EXEC if 461 * binary' file comes from noexec mount. We cannot 462 * set VV_TEXT on the binary. 463 */ 464 dir_enable = false; 465 if (st.st_uid == geteuid()) { 466 if ((st.st_mode & S_IXUSR) != 0) 467 dir_enable = true; 468 } else if (st.st_gid == getegid()) { 469 if ((st.st_mode & S_IXGRP) != 0) 470 dir_enable = true; 471 } else if ((st.st_mode & S_IXOTH) != 0) { 472 dir_enable = true; 473 } 474 if (!dir_enable) { 475 rtld_printf("No execute permission for binary %s\n", 476 argv0); 477 rtld_die(); 478 } 479 480 /* 481 * For direct exec mode, argv[0] is the interpreter 482 * name, we must remove it and shift arguments left 483 * before invoking binary main. Since stack layout 484 * places environment pointers and aux vectors right 485 * after the terminating NULL, we must shift 486 * environment and aux as well. 487 */ 488 main_argc = argc - rtld_argc; 489 for (i = 0; i <= main_argc; i++) 490 argv[i] = argv[i + rtld_argc]; 491 *argcp -= rtld_argc; 492 environ = env = envp = argv + main_argc + 1; 493 do { 494 *envp = *(envp + rtld_argc); 495 envp++; 496 } while (*envp != NULL); 497 aux = auxp = (Elf_Auxinfo *)envp; 498 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 499 for (;; auxp++, auxpf++) { 500 *auxp = *auxpf; 501 if (auxp->a_type == AT_NULL) 502 break; 503 } 504 } else { 505 rtld_printf("no binary\n"); 506 rtld_die(); 507 } 508 } 509 } 510 511 ld_bind_now = getenv(_LD("BIND_NOW")); 512 513 /* 514 * If the process is tainted, then we un-set the dangerous environment 515 * variables. The process will be marked as tainted until setuid(2) 516 * is called. If any child process calls setuid(2) we do not want any 517 * future processes to honor the potentially un-safe variables. 518 */ 519 if (!trust) { 520 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 521 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 522 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 523 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 524 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 525 _rtld_error("environment corrupt; aborting"); 526 rtld_die(); 527 } 528 } 529 ld_debug = getenv(_LD("DEBUG")); 530 if (ld_bind_now == NULL) 531 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 532 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 533 libmap_override = getenv(_LD("LIBMAP")); 534 ld_library_path = getenv(_LD("LIBRARY_PATH")); 535 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 536 ld_preload = getenv(_LD("PRELOAD")); 537 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 538 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 539 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 540 if (library_path_rpath != NULL) { 541 if (library_path_rpath[0] == 'y' || 542 library_path_rpath[0] == 'Y' || 543 library_path_rpath[0] == '1') 544 ld_library_path_rpath = true; 545 else 546 ld_library_path_rpath = false; 547 } 548 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 549 (ld_library_path != NULL) || (ld_preload != NULL) || 550 (ld_elf_hints_path != NULL) || ld_loadfltr; 551 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 552 ld_utrace = getenv(_LD("UTRACE")); 553 554 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 555 ld_elf_hints_path = ld_elf_hints_default; 556 557 if (ld_debug != NULL && *ld_debug != '\0') 558 debug = 1; 559 dbg("%s is initialized, base address = %p", __progname, 560 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 561 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 562 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 563 564 dbg("initializing thread locks"); 565 lockdflt_init(); 566 567 /* 568 * Load the main program, or process its program header if it is 569 * already loaded. 570 */ 571 if (fd != -1) { /* Load the main program. */ 572 dbg("loading main program"); 573 obj_main = map_object(fd, argv0, NULL); 574 close(fd); 575 if (obj_main == NULL) 576 rtld_die(); 577 max_stack_flags = obj_main->stack_flags; 578 } else { /* Main program already loaded. */ 579 dbg("processing main program's program header"); 580 assert(aux_info[AT_PHDR] != NULL); 581 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 582 assert(aux_info[AT_PHNUM] != NULL); 583 phnum = aux_info[AT_PHNUM]->a_un.a_val; 584 assert(aux_info[AT_PHENT] != NULL); 585 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 586 assert(aux_info[AT_ENTRY] != NULL); 587 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 588 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 589 rtld_die(); 590 } 591 592 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 593 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 594 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 595 if (kexecpath[0] == '/') 596 obj_main->path = kexecpath; 597 else if (getcwd(buf, sizeof(buf)) == NULL || 598 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 599 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 600 obj_main->path = xstrdup(argv0); 601 else 602 obj_main->path = xstrdup(buf); 603 } else { 604 dbg("No AT_EXECPATH or direct exec"); 605 obj_main->path = xstrdup(argv0); 606 } 607 dbg("obj_main path %s", obj_main->path); 608 obj_main->mainprog = true; 609 610 if (aux_info[AT_STACKPROT] != NULL && 611 aux_info[AT_STACKPROT]->a_un.a_val != 0) 612 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 613 614#ifndef COMPAT_32BIT 615 /* 616 * Get the actual dynamic linker pathname from the executable if 617 * possible. (It should always be possible.) That ensures that 618 * gdb will find the right dynamic linker even if a non-standard 619 * one is being used. 620 */ 621 if (obj_main->interp != NULL && 622 strcmp(obj_main->interp, obj_rtld.path) != 0) { 623 free(obj_rtld.path); 624 obj_rtld.path = xstrdup(obj_main->interp); 625 __progname = obj_rtld.path; 626 } 627#endif 628 629 digest_dynamic(obj_main, 0); 630 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 631 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 632 obj_main->dynsymcount); 633 634 linkmap_add(obj_main); 635 linkmap_add(&obj_rtld); 636 637 /* Link the main program into the list of objects. */ 638 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 639 obj_count++; 640 obj_loads++; 641 642 /* Initialize a fake symbol for resolving undefined weak references. */ 643 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 644 sym_zero.st_shndx = SHN_UNDEF; 645 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 646 647 if (!libmap_disable) 648 libmap_disable = (bool)lm_init(libmap_override); 649 650 dbg("loading LD_PRELOAD libraries"); 651 if (load_preload_objects() == -1) 652 rtld_die(); 653 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 654 655 dbg("loading needed objects"); 656 if (load_needed_objects(obj_main, 0) == -1) 657 rtld_die(); 658 659 /* Make a list of all objects loaded at startup. */ 660 last_interposer = obj_main; 661 TAILQ_FOREACH(obj, &obj_list, next) { 662 if (obj->marker) 663 continue; 664 if (obj->z_interpose && obj != obj_main) { 665 objlist_put_after(&list_main, last_interposer, obj); 666 last_interposer = obj; 667 } else { 668 objlist_push_tail(&list_main, obj); 669 } 670 obj->refcount++; 671 } 672 673 dbg("checking for required versions"); 674 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 675 rtld_die(); 676 677 if (ld_tracing) { /* We're done */ 678 trace_loaded_objects(obj_main); 679 exit(0); 680 } 681 682 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 683 dump_relocations(obj_main); 684 exit (0); 685 } 686 687 /* 688 * Processing tls relocations requires having the tls offsets 689 * initialized. Prepare offsets before starting initial 690 * relocation processing. 691 */ 692 dbg("initializing initial thread local storage offsets"); 693 STAILQ_FOREACH(entry, &list_main, link) { 694 /* 695 * Allocate all the initial objects out of the static TLS 696 * block even if they didn't ask for it. 697 */ 698 allocate_tls_offset(entry->obj); 699 } 700 701 if (relocate_objects(obj_main, 702 ld_bind_now != NULL && *ld_bind_now != '\0', 703 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 704 rtld_die(); 705 706 dbg("doing copy relocations"); 707 if (do_copy_relocations(obj_main) == -1) 708 rtld_die(); 709 710 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 711 dump_relocations(obj_main); 712 exit (0); 713 } 714 715 ifunc_init(aux); 716 717 /* 718 * Setup TLS for main thread. This must be done after the 719 * relocations are processed, since tls initialization section 720 * might be the subject for relocations. 721 */ 722 dbg("initializing initial thread local storage"); 723 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 724 725 dbg("initializing key program variables"); 726 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 727 set_program_var("environ", env); 728 set_program_var("__elf_aux_vector", aux); 729 730 /* Make a list of init functions to call. */ 731 objlist_init(&initlist); 732 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 733 preload_tail, &initlist); 734 735 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 736 737 map_stacks_exec(NULL); 738 739 if (!obj_main->crt_no_init) { 740 /* 741 * Make sure we don't call the main program's init and fini 742 * functions for binaries linked with old crt1 which calls 743 * _init itself. 744 */ 745 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 746 obj_main->preinit_array = obj_main->init_array = 747 obj_main->fini_array = (Elf_Addr)NULL; 748 } 749 750 /* 751 * Execute MD initializers required before we call the objects' 752 * init functions. 753 */ 754 pre_init(); 755 756 wlock_acquire(rtld_bind_lock, &lockstate); 757 758 dbg("resolving ifuncs"); 759 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 760 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 761 rtld_die(); 762 763 if (obj_main->crt_no_init) 764 preinit_main(); 765 objlist_call_init(&initlist, &lockstate); 766 _r_debug_postinit(&obj_main->linkmap); 767 objlist_clear(&initlist); 768 dbg("loading filtees"); 769 TAILQ_FOREACH(obj, &obj_list, next) { 770 if (obj->marker) 771 continue; 772 if (ld_loadfltr || obj->z_loadfltr) 773 load_filtees(obj, 0, &lockstate); 774 } 775 776 dbg("enforcing main obj relro"); 777 if (obj_enforce_relro(obj_main) == -1) 778 rtld_die(); 779 780 lock_release(rtld_bind_lock, &lockstate); 781 782 dbg("transferring control to program entry point = %p", obj_main->entry); 783 784 /* Return the exit procedure and the program entry point. */ 785 *exit_proc = rtld_exit; 786 *objp = obj_main; 787 return (func_ptr_type) obj_main->entry; 788} 789 790void * 791rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 792{ 793 void *ptr; 794 Elf_Addr target; 795 796 ptr = (void *)make_function_pointer(def, obj); 797 target = call_ifunc_resolver(ptr); 798 return ((void *)target); 799} 800 801/* 802 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 803 * Changes to this function should be applied there as well. 804 */ 805Elf_Addr 806_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 807{ 808 const Elf_Rel *rel; 809 const Elf_Sym *def; 810 const Obj_Entry *defobj; 811 Elf_Addr *where; 812 Elf_Addr target; 813 RtldLockState lockstate; 814 815 rlock_acquire(rtld_bind_lock, &lockstate); 816 if (sigsetjmp(lockstate.env, 0) != 0) 817 lock_upgrade(rtld_bind_lock, &lockstate); 818 if (obj->pltrel) 819 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 820 else 821 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 822 823 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 824 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 825 NULL, &lockstate); 826 if (def == NULL) 827 rtld_die(); 828 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 829 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 830 else 831 target = (Elf_Addr)(defobj->relocbase + def->st_value); 832 833 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 834 defobj->strtab + def->st_name, basename(obj->path), 835 (void *)target, basename(defobj->path)); 836 837 /* 838 * Write the new contents for the jmpslot. Note that depending on 839 * architecture, the value which we need to return back to the 840 * lazy binding trampoline may or may not be the target 841 * address. The value returned from reloc_jmpslot() is the value 842 * that the trampoline needs. 843 */ 844 target = reloc_jmpslot(where, target, defobj, obj, rel); 845 lock_release(rtld_bind_lock, &lockstate); 846 return target; 847} 848 849/* 850 * Error reporting function. Use it like printf. If formats the message 851 * into a buffer, and sets things up so that the next call to dlerror() 852 * will return the message. 853 */ 854void 855_rtld_error(const char *fmt, ...) 856{ 857 static char buf[512]; 858 va_list ap; 859 860 va_start(ap, fmt); 861 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 862 error_message = buf; 863 va_end(ap); 864} 865 866/* 867 * Return a dynamically-allocated copy of the current error message, if any. 868 */ 869static char * 870errmsg_save(void) 871{ 872 return error_message == NULL ? NULL : xstrdup(error_message); 873} 874 875/* 876 * Restore the current error message from a copy which was previously saved 877 * by errmsg_save(). The copy is freed. 878 */ 879static void 880errmsg_restore(char *saved_msg) 881{ 882 if (saved_msg == NULL) 883 error_message = NULL; 884 else { 885 _rtld_error("%s", saved_msg); 886 free(saved_msg); 887 } 888} 889 890static const char * 891basename(const char *name) 892{ 893 const char *p = strrchr(name, '/'); 894 return p != NULL ? p + 1 : name; 895} 896 897static struct utsname uts; 898 899static char * 900origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 901 const char *subst, bool may_free) 902{ 903 char *p, *p1, *res, *resp; 904 int subst_len, kw_len, subst_count, old_len, new_len; 905 906 kw_len = strlen(kw); 907 908 /* 909 * First, count the number of the keyword occurrences, to 910 * preallocate the final string. 911 */ 912 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 913 p1 = strstr(p, kw); 914 if (p1 == NULL) 915 break; 916 } 917 918 /* 919 * If the keyword is not found, just return. 920 * 921 * Return non-substituted string if resolution failed. We 922 * cannot do anything more reasonable, the failure mode of the 923 * caller is unresolved library anyway. 924 */ 925 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 926 return (may_free ? real : xstrdup(real)); 927 if (obj != NULL) 928 subst = obj->origin_path; 929 930 /* 931 * There is indeed something to substitute. Calculate the 932 * length of the resulting string, and allocate it. 933 */ 934 subst_len = strlen(subst); 935 old_len = strlen(real); 936 new_len = old_len + (subst_len - kw_len) * subst_count; 937 res = xmalloc(new_len + 1); 938 939 /* 940 * Now, execute the substitution loop. 941 */ 942 for (p = real, resp = res, *resp = '\0';;) { 943 p1 = strstr(p, kw); 944 if (p1 != NULL) { 945 /* Copy the prefix before keyword. */ 946 memcpy(resp, p, p1 - p); 947 resp += p1 - p; 948 /* Keyword replacement. */ 949 memcpy(resp, subst, subst_len); 950 resp += subst_len; 951 *resp = '\0'; 952 p = p1 + kw_len; 953 } else 954 break; 955 } 956 957 /* Copy to the end of string and finish. */ 958 strcat(resp, p); 959 if (may_free) 960 free(real); 961 return (res); 962} 963 964static char * 965origin_subst(Obj_Entry *obj, char *real) 966{ 967 char *res1, *res2, *res3, *res4; 968 969 if (obj == NULL || !trust) 970 return (xstrdup(real)); 971 if (uts.sysname[0] == '\0') { 972 if (uname(&uts) != 0) { 973 _rtld_error("utsname failed: %d", errno); 974 return (NULL); 975 } 976 } 977 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 978 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 979 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 980 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 981 return (res4); 982} 983 984void 985rtld_die(void) 986{ 987 const char *msg = dlerror(); 988 989 if (msg == NULL) 990 msg = "Fatal error"; 991 rtld_fdputstr(STDERR_FILENO, msg); 992 rtld_fdputchar(STDERR_FILENO, '\n'); 993 _exit(1); 994} 995 996/* 997 * Process a shared object's DYNAMIC section, and save the important 998 * information in its Obj_Entry structure. 999 */ 1000static void 1001digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1002 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1003{ 1004 const Elf_Dyn *dynp; 1005 Needed_Entry **needed_tail = &obj->needed; 1006 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1007 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1008 const Elf_Hashelt *hashtab; 1009 const Elf32_Word *hashval; 1010 Elf32_Word bkt, nmaskwords; 1011 int bloom_size32; 1012 int plttype = DT_REL; 1013 1014 *dyn_rpath = NULL; 1015 *dyn_soname = NULL; 1016 *dyn_runpath = NULL; 1017 1018 obj->bind_now = false; 1019 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1020 switch (dynp->d_tag) { 1021 1022 case DT_REL: 1023 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1024 break; 1025 1026 case DT_RELSZ: 1027 obj->relsize = dynp->d_un.d_val; 1028 break; 1029 1030 case DT_RELENT: 1031 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1032 break; 1033 1034 case DT_JMPREL: 1035 obj->pltrel = (const Elf_Rel *) 1036 (obj->relocbase + dynp->d_un.d_ptr); 1037 break; 1038 1039 case DT_PLTRELSZ: 1040 obj->pltrelsize = dynp->d_un.d_val; 1041 break; 1042 1043 case DT_RELA: 1044 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1045 break; 1046 1047 case DT_RELASZ: 1048 obj->relasize = dynp->d_un.d_val; 1049 break; 1050 1051 case DT_RELAENT: 1052 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1053 break; 1054 1055 case DT_PLTREL: 1056 plttype = dynp->d_un.d_val; 1057 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1058 break; 1059 1060 case DT_SYMTAB: 1061 obj->symtab = (const Elf_Sym *) 1062 (obj->relocbase + dynp->d_un.d_ptr); 1063 break; 1064 1065 case DT_SYMENT: 1066 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1067 break; 1068 1069 case DT_STRTAB: 1070 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1071 break; 1072 1073 case DT_STRSZ: 1074 obj->strsize = dynp->d_un.d_val; 1075 break; 1076 1077 case DT_VERNEED: 1078 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1079 dynp->d_un.d_val); 1080 break; 1081 1082 case DT_VERNEEDNUM: 1083 obj->verneednum = dynp->d_un.d_val; 1084 break; 1085 1086 case DT_VERDEF: 1087 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1088 dynp->d_un.d_val); 1089 break; 1090 1091 case DT_VERDEFNUM: 1092 obj->verdefnum = dynp->d_un.d_val; 1093 break; 1094 1095 case DT_VERSYM: 1096 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1097 dynp->d_un.d_val); 1098 break; 1099 1100 case DT_HASH: 1101 { 1102 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1103 dynp->d_un.d_ptr); 1104 obj->nbuckets = hashtab[0]; 1105 obj->nchains = hashtab[1]; 1106 obj->buckets = hashtab + 2; 1107 obj->chains = obj->buckets + obj->nbuckets; 1108 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1109 obj->buckets != NULL; 1110 } 1111 break; 1112 1113 case DT_GNU_HASH: 1114 { 1115 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1116 dynp->d_un.d_ptr); 1117 obj->nbuckets_gnu = hashtab[0]; 1118 obj->symndx_gnu = hashtab[1]; 1119 nmaskwords = hashtab[2]; 1120 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1121 obj->maskwords_bm_gnu = nmaskwords - 1; 1122 obj->shift2_gnu = hashtab[3]; 1123 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1124 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1125 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1126 obj->symndx_gnu; 1127 /* Number of bitmask words is required to be power of 2 */ 1128 obj->valid_hash_gnu = powerof2(nmaskwords) && 1129 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1130 } 1131 break; 1132 1133 case DT_NEEDED: 1134 if (!obj->rtld) { 1135 Needed_Entry *nep = NEW(Needed_Entry); 1136 nep->name = dynp->d_un.d_val; 1137 nep->obj = NULL; 1138 nep->next = NULL; 1139 1140 *needed_tail = nep; 1141 needed_tail = &nep->next; 1142 } 1143 break; 1144 1145 case DT_FILTER: 1146 if (!obj->rtld) { 1147 Needed_Entry *nep = NEW(Needed_Entry); 1148 nep->name = dynp->d_un.d_val; 1149 nep->obj = NULL; 1150 nep->next = NULL; 1151 1152 *needed_filtees_tail = nep; 1153 needed_filtees_tail = &nep->next; 1154 } 1155 break; 1156 1157 case DT_AUXILIARY: 1158 if (!obj->rtld) { 1159 Needed_Entry *nep = NEW(Needed_Entry); 1160 nep->name = dynp->d_un.d_val; 1161 nep->obj = NULL; 1162 nep->next = NULL; 1163 1164 *needed_aux_filtees_tail = nep; 1165 needed_aux_filtees_tail = &nep->next; 1166 } 1167 break; 1168 1169 case DT_PLTGOT: 1170 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1171 break; 1172 1173 case DT_TEXTREL: 1174 obj->textrel = true; 1175 break; 1176 1177 case DT_SYMBOLIC: 1178 obj->symbolic = true; 1179 break; 1180 1181 case DT_RPATH: 1182 /* 1183 * We have to wait until later to process this, because we 1184 * might not have gotten the address of the string table yet. 1185 */ 1186 *dyn_rpath = dynp; 1187 break; 1188 1189 case DT_SONAME: 1190 *dyn_soname = dynp; 1191 break; 1192 1193 case DT_RUNPATH: 1194 *dyn_runpath = dynp; 1195 break; 1196 1197 case DT_INIT: 1198 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1199 break; 1200 1201 case DT_PREINIT_ARRAY: 1202 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1203 break; 1204 1205 case DT_PREINIT_ARRAYSZ: 1206 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1207 break; 1208 1209 case DT_INIT_ARRAY: 1210 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1211 break; 1212 1213 case DT_INIT_ARRAYSZ: 1214 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1215 break; 1216 1217 case DT_FINI: 1218 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1219 break; 1220 1221 case DT_FINI_ARRAY: 1222 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1223 break; 1224 1225 case DT_FINI_ARRAYSZ: 1226 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1227 break; 1228 1229 /* 1230 * Don't process DT_DEBUG on MIPS as the dynamic section 1231 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1232 */ 1233 1234#ifndef __mips__ 1235 case DT_DEBUG: 1236 if (!early) 1237 dbg("Filling in DT_DEBUG entry"); 1238 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1239 break; 1240#endif 1241 1242 case DT_FLAGS: 1243 if (dynp->d_un.d_val & DF_ORIGIN) 1244 obj->z_origin = true; 1245 if (dynp->d_un.d_val & DF_SYMBOLIC) 1246 obj->symbolic = true; 1247 if (dynp->d_un.d_val & DF_TEXTREL) 1248 obj->textrel = true; 1249 if (dynp->d_un.d_val & DF_BIND_NOW) 1250 obj->bind_now = true; 1251 if (dynp->d_un.d_val & DF_STATIC_TLS) 1252 obj->static_tls = true; 1253 break; 1254#ifdef __mips__ 1255 case DT_MIPS_LOCAL_GOTNO: 1256 obj->local_gotno = dynp->d_un.d_val; 1257 break; 1258 1259 case DT_MIPS_SYMTABNO: 1260 obj->symtabno = dynp->d_un.d_val; 1261 break; 1262 1263 case DT_MIPS_GOTSYM: 1264 obj->gotsym = dynp->d_un.d_val; 1265 break; 1266 1267 case DT_MIPS_RLD_MAP: 1268 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1269 break; 1270#endif 1271 1272#ifdef __powerpc64__ 1273 case DT_PPC64_GLINK: 1274 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1275 break; 1276#endif 1277 1278 case DT_FLAGS_1: 1279 if (dynp->d_un.d_val & DF_1_NOOPEN) 1280 obj->z_noopen = true; 1281 if (dynp->d_un.d_val & DF_1_ORIGIN) 1282 obj->z_origin = true; 1283 if (dynp->d_un.d_val & DF_1_GLOBAL) 1284 obj->z_global = true; 1285 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1286 obj->bind_now = true; 1287 if (dynp->d_un.d_val & DF_1_NODELETE) 1288 obj->z_nodelete = true; 1289 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1290 obj->z_loadfltr = true; 1291 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1292 obj->z_interpose = true; 1293 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1294 obj->z_nodeflib = true; 1295 break; 1296 1297 default: 1298 if (!early) { 1299 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1300 (long)dynp->d_tag); 1301 } 1302 break; 1303 } 1304 } 1305 1306 obj->traced = false; 1307 1308 if (plttype == DT_RELA) { 1309 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1310 obj->pltrel = NULL; 1311 obj->pltrelasize = obj->pltrelsize; 1312 obj->pltrelsize = 0; 1313 } 1314 1315 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1316 if (obj->valid_hash_sysv) 1317 obj->dynsymcount = obj->nchains; 1318 else if (obj->valid_hash_gnu) { 1319 obj->dynsymcount = 0; 1320 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1321 if (obj->buckets_gnu[bkt] == 0) 1322 continue; 1323 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1324 do 1325 obj->dynsymcount++; 1326 while ((*hashval++ & 1u) == 0); 1327 } 1328 obj->dynsymcount += obj->symndx_gnu; 1329 } 1330} 1331 1332static bool 1333obj_resolve_origin(Obj_Entry *obj) 1334{ 1335 1336 if (obj->origin_path != NULL) 1337 return (true); 1338 obj->origin_path = xmalloc(PATH_MAX); 1339 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1340} 1341 1342static void 1343digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1344 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1345{ 1346 1347 if (obj->z_origin && !obj_resolve_origin(obj)) 1348 rtld_die(); 1349 1350 if (dyn_runpath != NULL) { 1351 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1352 obj->runpath = origin_subst(obj, obj->runpath); 1353 } else if (dyn_rpath != NULL) { 1354 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1355 obj->rpath = origin_subst(obj, obj->rpath); 1356 } 1357 if (dyn_soname != NULL) 1358 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1359} 1360 1361static void 1362digest_dynamic(Obj_Entry *obj, int early) 1363{ 1364 const Elf_Dyn *dyn_rpath; 1365 const Elf_Dyn *dyn_soname; 1366 const Elf_Dyn *dyn_runpath; 1367 1368 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1369 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1370} 1371 1372/* 1373 * Process a shared object's program header. This is used only for the 1374 * main program, when the kernel has already loaded the main program 1375 * into memory before calling the dynamic linker. It creates and 1376 * returns an Obj_Entry structure. 1377 */ 1378static Obj_Entry * 1379digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1380{ 1381 Obj_Entry *obj; 1382 const Elf_Phdr *phlimit = phdr + phnum; 1383 const Elf_Phdr *ph; 1384 Elf_Addr note_start, note_end; 1385 int nsegs = 0; 1386 1387 obj = obj_new(); 1388 for (ph = phdr; ph < phlimit; ph++) { 1389 if (ph->p_type != PT_PHDR) 1390 continue; 1391 1392 obj->phdr = phdr; 1393 obj->phsize = ph->p_memsz; 1394 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1395 break; 1396 } 1397 1398 obj->stack_flags = PF_X | PF_R | PF_W; 1399 1400 for (ph = phdr; ph < phlimit; ph++) { 1401 switch (ph->p_type) { 1402 1403 case PT_INTERP: 1404 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1405 break; 1406 1407 case PT_LOAD: 1408 if (nsegs == 0) { /* First load segment */ 1409 obj->vaddrbase = trunc_page(ph->p_vaddr); 1410 obj->mapbase = obj->vaddrbase + obj->relocbase; 1411 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1412 obj->vaddrbase; 1413 } else { /* Last load segment */ 1414 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1415 obj->vaddrbase; 1416 } 1417 nsegs++; 1418 break; 1419 1420 case PT_DYNAMIC: 1421 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1422 break; 1423 1424 case PT_TLS: 1425 obj->tlsindex = 1; 1426 obj->tlssize = ph->p_memsz; 1427 obj->tlsalign = ph->p_align; 1428 obj->tlsinitsize = ph->p_filesz; 1429 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1430 break; 1431 1432 case PT_GNU_STACK: 1433 obj->stack_flags = ph->p_flags; 1434 break; 1435 1436 case PT_GNU_RELRO: 1437 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1438 obj->relro_size = round_page(ph->p_memsz); 1439 break; 1440 1441 case PT_NOTE: 1442 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1443 note_end = note_start + ph->p_filesz; 1444 digest_notes(obj, note_start, note_end); 1445 break; 1446 } 1447 } 1448 if (nsegs < 1) { 1449 _rtld_error("%s: too few PT_LOAD segments", path); 1450 return NULL; 1451 } 1452 1453 obj->entry = entry; 1454 return obj; 1455} 1456 1457void 1458digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1459{ 1460 const Elf_Note *note; 1461 const char *note_name; 1462 uintptr_t p; 1463 1464 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1465 note = (const Elf_Note *)((const char *)(note + 1) + 1466 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1467 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1468 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1469 note->n_descsz != sizeof(int32_t)) 1470 continue; 1471 if (note->n_type != NT_FREEBSD_ABI_TAG && 1472 note->n_type != NT_FREEBSD_NOINIT_TAG) 1473 continue; 1474 note_name = (const char *)(note + 1); 1475 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1476 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1477 continue; 1478 switch (note->n_type) { 1479 case NT_FREEBSD_ABI_TAG: 1480 /* FreeBSD osrel note */ 1481 p = (uintptr_t)(note + 1); 1482 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1483 obj->osrel = *(const int32_t *)(p); 1484 dbg("note osrel %d", obj->osrel); 1485 break; 1486 case NT_FREEBSD_NOINIT_TAG: 1487 /* FreeBSD 'crt does not call init' note */ 1488 obj->crt_no_init = true; 1489 dbg("note crt_no_init"); 1490 break; 1491 } 1492 } 1493} 1494 1495static Obj_Entry * 1496dlcheck(void *handle) 1497{ 1498 Obj_Entry *obj; 1499 1500 TAILQ_FOREACH(obj, &obj_list, next) { 1501 if (obj == (Obj_Entry *) handle) 1502 break; 1503 } 1504 1505 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1506 _rtld_error("Invalid shared object handle %p", handle); 1507 return NULL; 1508 } 1509 return obj; 1510} 1511 1512/* 1513 * If the given object is already in the donelist, return true. Otherwise 1514 * add the object to the list and return false. 1515 */ 1516static bool 1517donelist_check(DoneList *dlp, const Obj_Entry *obj) 1518{ 1519 unsigned int i; 1520 1521 for (i = 0; i < dlp->num_used; i++) 1522 if (dlp->objs[i] == obj) 1523 return true; 1524 /* 1525 * Our donelist allocation should always be sufficient. But if 1526 * our threads locking isn't working properly, more shared objects 1527 * could have been loaded since we allocated the list. That should 1528 * never happen, but we'll handle it properly just in case it does. 1529 */ 1530 if (dlp->num_used < dlp->num_alloc) 1531 dlp->objs[dlp->num_used++] = obj; 1532 return false; 1533} 1534 1535/* 1536 * Hash function for symbol table lookup. Don't even think about changing 1537 * this. It is specified by the System V ABI. 1538 */ 1539unsigned long 1540elf_hash(const char *name) 1541{ 1542 const unsigned char *p = (const unsigned char *) name; 1543 unsigned long h = 0; 1544 unsigned long g; 1545 1546 while (*p != '\0') { 1547 h = (h << 4) + *p++; 1548 if ((g = h & 0xf0000000) != 0) 1549 h ^= g >> 24; 1550 h &= ~g; 1551 } 1552 return h; 1553} 1554 1555/* 1556 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1557 * unsigned in case it's implemented with a wider type. 1558 */ 1559static uint32_t 1560gnu_hash(const char *s) 1561{ 1562 uint32_t h; 1563 unsigned char c; 1564 1565 h = 5381; 1566 for (c = *s; c != '\0'; c = *++s) 1567 h = h * 33 + c; 1568 return (h & 0xffffffff); 1569} 1570 1571 1572/* 1573 * Find the library with the given name, and return its full pathname. 1574 * The returned string is dynamically allocated. Generates an error 1575 * message and returns NULL if the library cannot be found. 1576 * 1577 * If the second argument is non-NULL, then it refers to an already- 1578 * loaded shared object, whose library search path will be searched. 1579 * 1580 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1581 * descriptor (which is close-on-exec) will be passed out via the third 1582 * argument. 1583 * 1584 * The search order is: 1585 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1586 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1587 * LD_LIBRARY_PATH 1588 * DT_RUNPATH in the referencing file 1589 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1590 * from list) 1591 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1592 * 1593 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1594 */ 1595static char * 1596find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1597{ 1598 char *name, *pathname, *refobj_path; 1599 bool nodeflib, objgiven; 1600 1601 objgiven = refobj != NULL; 1602 1603 if (libmap_disable || !objgiven || 1604 (name = lm_find(refobj->path, xname)) == NULL) 1605 name = (char *)xname; 1606 1607 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1608 if (name[0] != '/' && !trust) { 1609 _rtld_error("Absolute pathname required " 1610 "for shared object \"%s\"", name); 1611 return (NULL); 1612 } 1613 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1614 __DECONST(char *, name))); 1615 } 1616 1617 dbg(" Searching for \"%s\"", name); 1618 refobj_path = objgiven ? refobj->path : NULL; 1619 1620 /* 1621 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1622 * back to pre-conforming behaviour if user requested so with 1623 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1624 * nodeflib. 1625 */ 1626 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1627 pathname = search_library_path(name, ld_library_path, 1628 refobj_path, fdp); 1629 if (pathname != NULL) 1630 return (pathname); 1631 if (refobj != NULL) { 1632 pathname = search_library_path(name, refobj->rpath, 1633 refobj_path, fdp); 1634 if (pathname != NULL) 1635 return (pathname); 1636 } 1637 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1638 if (pathname != NULL) 1639 return (pathname); 1640 pathname = search_library_path(name, gethints(false), 1641 refobj_path, fdp); 1642 if (pathname != NULL) 1643 return (pathname); 1644 pathname = search_library_path(name, ld_standard_library_path, 1645 refobj_path, fdp); 1646 if (pathname != NULL) 1647 return (pathname); 1648 } else { 1649 nodeflib = objgiven ? refobj->z_nodeflib : false; 1650 if (objgiven) { 1651 pathname = search_library_path(name, refobj->rpath, 1652 refobj->path, fdp); 1653 if (pathname != NULL) 1654 return (pathname); 1655 } 1656 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1657 pathname = search_library_path(name, obj_main->rpath, 1658 refobj_path, fdp); 1659 if (pathname != NULL) 1660 return (pathname); 1661 } 1662 pathname = search_library_path(name, ld_library_path, 1663 refobj_path, fdp); 1664 if (pathname != NULL) 1665 return (pathname); 1666 if (objgiven) { 1667 pathname = search_library_path(name, refobj->runpath, 1668 refobj_path, fdp); 1669 if (pathname != NULL) 1670 return (pathname); 1671 } 1672 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1673 if (pathname != NULL) 1674 return (pathname); 1675 pathname = search_library_path(name, gethints(nodeflib), 1676 refobj_path, fdp); 1677 if (pathname != NULL) 1678 return (pathname); 1679 if (objgiven && !nodeflib) { 1680 pathname = search_library_path(name, 1681 ld_standard_library_path, refobj_path, fdp); 1682 if (pathname != NULL) 1683 return (pathname); 1684 } 1685 } 1686 1687 if (objgiven && refobj->path != NULL) { 1688 _rtld_error("Shared object \"%s\" not found, " 1689 "required by \"%s\"", name, basename(refobj->path)); 1690 } else { 1691 _rtld_error("Shared object \"%s\" not found", name); 1692 } 1693 return (NULL); 1694} 1695 1696/* 1697 * Given a symbol number in a referencing object, find the corresponding 1698 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1699 * no definition was found. Returns a pointer to the Obj_Entry of the 1700 * defining object via the reference parameter DEFOBJ_OUT. 1701 */ 1702const Elf_Sym * 1703find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1704 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1705 RtldLockState *lockstate) 1706{ 1707 const Elf_Sym *ref; 1708 const Elf_Sym *def; 1709 const Obj_Entry *defobj; 1710 const Ver_Entry *ve; 1711 SymLook req; 1712 const char *name; 1713 int res; 1714 1715 /* 1716 * If we have already found this symbol, get the information from 1717 * the cache. 1718 */ 1719 if (symnum >= refobj->dynsymcount) 1720 return NULL; /* Bad object */ 1721 if (cache != NULL && cache[symnum].sym != NULL) { 1722 *defobj_out = cache[symnum].obj; 1723 return cache[symnum].sym; 1724 } 1725 1726 ref = refobj->symtab + symnum; 1727 name = refobj->strtab + ref->st_name; 1728 def = NULL; 1729 defobj = NULL; 1730 ve = NULL; 1731 1732 /* 1733 * We don't have to do a full scale lookup if the symbol is local. 1734 * We know it will bind to the instance in this load module; to 1735 * which we already have a pointer (ie ref). By not doing a lookup, 1736 * we not only improve performance, but it also avoids unresolvable 1737 * symbols when local symbols are not in the hash table. This has 1738 * been seen with the ia64 toolchain. 1739 */ 1740 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1741 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1742 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1743 symnum); 1744 } 1745 symlook_init(&req, name); 1746 req.flags = flags; 1747 ve = req.ventry = fetch_ventry(refobj, symnum); 1748 req.lockstate = lockstate; 1749 res = symlook_default(&req, refobj); 1750 if (res == 0) { 1751 def = req.sym_out; 1752 defobj = req.defobj_out; 1753 } 1754 } else { 1755 def = ref; 1756 defobj = refobj; 1757 } 1758 1759 /* 1760 * If we found no definition and the reference is weak, treat the 1761 * symbol as having the value zero. 1762 */ 1763 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1764 def = &sym_zero; 1765 defobj = obj_main; 1766 } 1767 1768 if (def != NULL) { 1769 *defobj_out = defobj; 1770 /* Record the information in the cache to avoid subsequent lookups. */ 1771 if (cache != NULL) { 1772 cache[symnum].sym = def; 1773 cache[symnum].obj = defobj; 1774 } 1775 } else { 1776 if (refobj != &obj_rtld) 1777 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1778 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1779 } 1780 return def; 1781} 1782 1783/* 1784 * Return the search path from the ldconfig hints file, reading it if 1785 * necessary. If nostdlib is true, then the default search paths are 1786 * not added to result. 1787 * 1788 * Returns NULL if there are problems with the hints file, 1789 * or if the search path there is empty. 1790 */ 1791static const char * 1792gethints(bool nostdlib) 1793{ 1794 static char *hints, *filtered_path; 1795 static struct elfhints_hdr hdr; 1796 struct fill_search_info_args sargs, hargs; 1797 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1798 struct dl_serpath *SLPpath, *hintpath; 1799 char *p; 1800 struct stat hint_stat; 1801 unsigned int SLPndx, hintndx, fndx, fcount; 1802 int fd; 1803 size_t flen; 1804 uint32_t dl; 1805 bool skip; 1806 1807 /* First call, read the hints file */ 1808 if (hints == NULL) { 1809 /* Keep from trying again in case the hints file is bad. */ 1810 hints = ""; 1811 1812 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1813 return (NULL); 1814 1815 /* 1816 * Check of hdr.dirlistlen value against type limit 1817 * intends to pacify static analyzers. Further 1818 * paranoia leads to checks that dirlist is fully 1819 * contained in the file range. 1820 */ 1821 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1822 hdr.magic != ELFHINTS_MAGIC || 1823 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1824 fstat(fd, &hint_stat) == -1) { 1825cleanup1: 1826 close(fd); 1827 hdr.dirlistlen = 0; 1828 return (NULL); 1829 } 1830 dl = hdr.strtab; 1831 if (dl + hdr.dirlist < dl) 1832 goto cleanup1; 1833 dl += hdr.dirlist; 1834 if (dl + hdr.dirlistlen < dl) 1835 goto cleanup1; 1836 dl += hdr.dirlistlen; 1837 if (dl > hint_stat.st_size) 1838 goto cleanup1; 1839 p = xmalloc(hdr.dirlistlen + 1); 1840 if (pread(fd, p, hdr.dirlistlen + 1, 1841 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1842 p[hdr.dirlistlen] != '\0') { 1843 free(p); 1844 goto cleanup1; 1845 } 1846 hints = p; 1847 close(fd); 1848 } 1849 1850 /* 1851 * If caller agreed to receive list which includes the default 1852 * paths, we are done. Otherwise, if we still did not 1853 * calculated filtered result, do it now. 1854 */ 1855 if (!nostdlib) 1856 return (hints[0] != '\0' ? hints : NULL); 1857 if (filtered_path != NULL) 1858 goto filt_ret; 1859 1860 /* 1861 * Obtain the list of all configured search paths, and the 1862 * list of the default paths. 1863 * 1864 * First estimate the size of the results. 1865 */ 1866 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1867 smeta.dls_cnt = 0; 1868 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1869 hmeta.dls_cnt = 0; 1870 1871 sargs.request = RTLD_DI_SERINFOSIZE; 1872 sargs.serinfo = &smeta; 1873 hargs.request = RTLD_DI_SERINFOSIZE; 1874 hargs.serinfo = &hmeta; 1875 1876 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1877 &sargs); 1878 path_enumerate(hints, fill_search_info, NULL, &hargs); 1879 1880 SLPinfo = xmalloc(smeta.dls_size); 1881 hintinfo = xmalloc(hmeta.dls_size); 1882 1883 /* 1884 * Next fetch both sets of paths. 1885 */ 1886 sargs.request = RTLD_DI_SERINFO; 1887 sargs.serinfo = SLPinfo; 1888 sargs.serpath = &SLPinfo->dls_serpath[0]; 1889 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1890 1891 hargs.request = RTLD_DI_SERINFO; 1892 hargs.serinfo = hintinfo; 1893 hargs.serpath = &hintinfo->dls_serpath[0]; 1894 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1895 1896 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1897 &sargs); 1898 path_enumerate(hints, fill_search_info, NULL, &hargs); 1899 1900 /* 1901 * Now calculate the difference between two sets, by excluding 1902 * standard paths from the full set. 1903 */ 1904 fndx = 0; 1905 fcount = 0; 1906 filtered_path = xmalloc(hdr.dirlistlen + 1); 1907 hintpath = &hintinfo->dls_serpath[0]; 1908 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1909 skip = false; 1910 SLPpath = &SLPinfo->dls_serpath[0]; 1911 /* 1912 * Check each standard path against current. 1913 */ 1914 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1915 /* matched, skip the path */ 1916 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1917 skip = true; 1918 break; 1919 } 1920 } 1921 if (skip) 1922 continue; 1923 /* 1924 * Not matched against any standard path, add the path 1925 * to result. Separate consequtive paths with ':'. 1926 */ 1927 if (fcount > 0) { 1928 filtered_path[fndx] = ':'; 1929 fndx++; 1930 } 1931 fcount++; 1932 flen = strlen(hintpath->dls_name); 1933 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1934 fndx += flen; 1935 } 1936 filtered_path[fndx] = '\0'; 1937 1938 free(SLPinfo); 1939 free(hintinfo); 1940 1941filt_ret: 1942 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1943} 1944 1945static void 1946init_dag(Obj_Entry *root) 1947{ 1948 const Needed_Entry *needed; 1949 const Objlist_Entry *elm; 1950 DoneList donelist; 1951 1952 if (root->dag_inited) 1953 return; 1954 donelist_init(&donelist); 1955 1956 /* Root object belongs to own DAG. */ 1957 objlist_push_tail(&root->dldags, root); 1958 objlist_push_tail(&root->dagmembers, root); 1959 donelist_check(&donelist, root); 1960 1961 /* 1962 * Add dependencies of root object to DAG in breadth order 1963 * by exploiting the fact that each new object get added 1964 * to the tail of the dagmembers list. 1965 */ 1966 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1967 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1968 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1969 continue; 1970 objlist_push_tail(&needed->obj->dldags, root); 1971 objlist_push_tail(&root->dagmembers, needed->obj); 1972 } 1973 } 1974 root->dag_inited = true; 1975} 1976 1977static void 1978init_marker(Obj_Entry *marker) 1979{ 1980 1981 bzero(marker, sizeof(*marker)); 1982 marker->marker = true; 1983} 1984 1985Obj_Entry * 1986globallist_curr(const Obj_Entry *obj) 1987{ 1988 1989 for (;;) { 1990 if (obj == NULL) 1991 return (NULL); 1992 if (!obj->marker) 1993 return (__DECONST(Obj_Entry *, obj)); 1994 obj = TAILQ_PREV(obj, obj_entry_q, next); 1995 } 1996} 1997 1998Obj_Entry * 1999globallist_next(const Obj_Entry *obj) 2000{ 2001 2002 for (;;) { 2003 obj = TAILQ_NEXT(obj, next); 2004 if (obj == NULL) 2005 return (NULL); 2006 if (!obj->marker) 2007 return (__DECONST(Obj_Entry *, obj)); 2008 } 2009} 2010 2011/* Prevent the object from being unmapped while the bind lock is dropped. */ 2012static void 2013hold_object(Obj_Entry *obj) 2014{ 2015 2016 obj->holdcount++; 2017} 2018 2019static void 2020unhold_object(Obj_Entry *obj) 2021{ 2022 2023 assert(obj->holdcount > 0); 2024 if (--obj->holdcount == 0 && obj->unholdfree) 2025 release_object(obj); 2026} 2027 2028static void 2029process_z(Obj_Entry *root) 2030{ 2031 const Objlist_Entry *elm; 2032 Obj_Entry *obj; 2033 2034 /* 2035 * Walk over object DAG and process every dependent object 2036 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2037 * to grow their own DAG. 2038 * 2039 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2040 * symlook_global() to work. 2041 * 2042 * For DF_1_NODELETE, the DAG should have its reference upped. 2043 */ 2044 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2045 obj = elm->obj; 2046 if (obj == NULL) 2047 continue; 2048 if (obj->z_nodelete && !obj->ref_nodel) { 2049 dbg("obj %s -z nodelete", obj->path); 2050 init_dag(obj); 2051 ref_dag(obj); 2052 obj->ref_nodel = true; 2053 } 2054 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2055 dbg("obj %s -z global", obj->path); 2056 objlist_push_tail(&list_global, obj); 2057 init_dag(obj); 2058 } 2059 } 2060} 2061/* 2062 * Initialize the dynamic linker. The argument is the address at which 2063 * the dynamic linker has been mapped into memory. The primary task of 2064 * this function is to relocate the dynamic linker. 2065 */ 2066static void 2067init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2068{ 2069 Obj_Entry objtmp; /* Temporary rtld object */ 2070 const Elf_Ehdr *ehdr; 2071 const Elf_Dyn *dyn_rpath; 2072 const Elf_Dyn *dyn_soname; 2073 const Elf_Dyn *dyn_runpath; 2074 2075#ifdef RTLD_INIT_PAGESIZES_EARLY 2076 /* The page size is required by the dynamic memory allocator. */ 2077 init_pagesizes(aux_info); 2078#endif 2079 2080 /* 2081 * Conjure up an Obj_Entry structure for the dynamic linker. 2082 * 2083 * The "path" member can't be initialized yet because string constants 2084 * cannot yet be accessed. Below we will set it correctly. 2085 */ 2086 memset(&objtmp, 0, sizeof(objtmp)); 2087 objtmp.path = NULL; 2088 objtmp.rtld = true; 2089 objtmp.mapbase = mapbase; 2090#ifdef PIC 2091 objtmp.relocbase = mapbase; 2092#endif 2093 2094 objtmp.dynamic = rtld_dynamic(&objtmp); 2095 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2096 assert(objtmp.needed == NULL); 2097#if !defined(__mips__) 2098 /* MIPS has a bogus DT_TEXTREL. */ 2099 assert(!objtmp.textrel); 2100#endif 2101 /* 2102 * Temporarily put the dynamic linker entry into the object list, so 2103 * that symbols can be found. 2104 */ 2105 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2106 2107 ehdr = (Elf_Ehdr *)mapbase; 2108 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2109 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2110 2111 /* Initialize the object list. */ 2112 TAILQ_INIT(&obj_list); 2113 2114 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2115 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2116 2117#ifndef RTLD_INIT_PAGESIZES_EARLY 2118 /* The page size is required by the dynamic memory allocator. */ 2119 init_pagesizes(aux_info); 2120#endif 2121 2122 if (aux_info[AT_OSRELDATE] != NULL) 2123 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2124 2125 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2126 2127 /* Replace the path with a dynamically allocated copy. */ 2128 obj_rtld.path = xstrdup(ld_path_rtld); 2129 2130 r_debug.r_brk = r_debug_state; 2131 r_debug.r_state = RT_CONSISTENT; 2132} 2133 2134/* 2135 * Retrieve the array of supported page sizes. The kernel provides the page 2136 * sizes in increasing order. 2137 */ 2138static void 2139init_pagesizes(Elf_Auxinfo **aux_info) 2140{ 2141 static size_t psa[MAXPAGESIZES]; 2142 int mib[2]; 2143 size_t len, size; 2144 2145 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2146 NULL) { 2147 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2148 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2149 } else { 2150 len = 2; 2151 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2152 size = sizeof(psa); 2153 else { 2154 /* As a fallback, retrieve the base page size. */ 2155 size = sizeof(psa[0]); 2156 if (aux_info[AT_PAGESZ] != NULL) { 2157 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2158 goto psa_filled; 2159 } else { 2160 mib[0] = CTL_HW; 2161 mib[1] = HW_PAGESIZE; 2162 len = 2; 2163 } 2164 } 2165 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2166 _rtld_error("sysctl for hw.pagesize(s) failed"); 2167 rtld_die(); 2168 } 2169psa_filled: 2170 pagesizes = psa; 2171 } 2172 npagesizes = size / sizeof(pagesizes[0]); 2173 /* Discard any invalid entries at the end of the array. */ 2174 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2175 npagesizes--; 2176} 2177 2178/* 2179 * Add the init functions from a needed object list (and its recursive 2180 * needed objects) to "list". This is not used directly; it is a helper 2181 * function for initlist_add_objects(). The write lock must be held 2182 * when this function is called. 2183 */ 2184static void 2185initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2186{ 2187 /* Recursively process the successor needed objects. */ 2188 if (needed->next != NULL) 2189 initlist_add_neededs(needed->next, list); 2190 2191 /* Process the current needed object. */ 2192 if (needed->obj != NULL) 2193 initlist_add_objects(needed->obj, needed->obj, list); 2194} 2195 2196/* 2197 * Scan all of the DAGs rooted in the range of objects from "obj" to 2198 * "tail" and add their init functions to "list". This recurses over 2199 * the DAGs and ensure the proper init ordering such that each object's 2200 * needed libraries are initialized before the object itself. At the 2201 * same time, this function adds the objects to the global finalization 2202 * list "list_fini" in the opposite order. The write lock must be 2203 * held when this function is called. 2204 */ 2205static void 2206initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2207{ 2208 Obj_Entry *nobj; 2209 2210 if (obj->init_scanned || obj->init_done) 2211 return; 2212 obj->init_scanned = true; 2213 2214 /* Recursively process the successor objects. */ 2215 nobj = globallist_next(obj); 2216 if (nobj != NULL && obj != tail) 2217 initlist_add_objects(nobj, tail, list); 2218 2219 /* Recursively process the needed objects. */ 2220 if (obj->needed != NULL) 2221 initlist_add_neededs(obj->needed, list); 2222 if (obj->needed_filtees != NULL) 2223 initlist_add_neededs(obj->needed_filtees, list); 2224 if (obj->needed_aux_filtees != NULL) 2225 initlist_add_neededs(obj->needed_aux_filtees, list); 2226 2227 /* Add the object to the init list. */ 2228 objlist_push_tail(list, obj); 2229 2230 /* Add the object to the global fini list in the reverse order. */ 2231 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2232 && !obj->on_fini_list) { 2233 objlist_push_head(&list_fini, obj); 2234 obj->on_fini_list = true; 2235 } 2236} 2237 2238#ifndef FPTR_TARGET 2239#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2240#endif 2241 2242static void 2243free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2244{ 2245 Needed_Entry *needed, *needed1; 2246 2247 for (needed = n; needed != NULL; needed = needed->next) { 2248 if (needed->obj != NULL) { 2249 dlclose_locked(needed->obj, lockstate); 2250 needed->obj = NULL; 2251 } 2252 } 2253 for (needed = n; needed != NULL; needed = needed1) { 2254 needed1 = needed->next; 2255 free(needed); 2256 } 2257} 2258 2259static void 2260unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2261{ 2262 2263 free_needed_filtees(obj->needed_filtees, lockstate); 2264 obj->needed_filtees = NULL; 2265 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2266 obj->needed_aux_filtees = NULL; 2267 obj->filtees_loaded = false; 2268} 2269 2270static void 2271load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2272 RtldLockState *lockstate) 2273{ 2274 2275 for (; needed != NULL; needed = needed->next) { 2276 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2277 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2278 RTLD_LOCAL, lockstate); 2279 } 2280} 2281 2282static void 2283load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2284{ 2285 2286 lock_restart_for_upgrade(lockstate); 2287 if (!obj->filtees_loaded) { 2288 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2289 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2290 obj->filtees_loaded = true; 2291 } 2292} 2293 2294static int 2295process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2296{ 2297 Obj_Entry *obj1; 2298 2299 for (; needed != NULL; needed = needed->next) { 2300 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2301 flags & ~RTLD_LO_NOLOAD); 2302 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2303 return (-1); 2304 } 2305 return (0); 2306} 2307 2308/* 2309 * Given a shared object, traverse its list of needed objects, and load 2310 * each of them. Returns 0 on success. Generates an error message and 2311 * returns -1 on failure. 2312 */ 2313static int 2314load_needed_objects(Obj_Entry *first, int flags) 2315{ 2316 Obj_Entry *obj; 2317 2318 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2319 if (obj->marker) 2320 continue; 2321 if (process_needed(obj, obj->needed, flags) == -1) 2322 return (-1); 2323 } 2324 return (0); 2325} 2326 2327static int 2328load_preload_objects(void) 2329{ 2330 char *p = ld_preload; 2331 Obj_Entry *obj; 2332 static const char delim[] = " \t:;"; 2333 2334 if (p == NULL) 2335 return 0; 2336 2337 p += strspn(p, delim); 2338 while (*p != '\0') { 2339 size_t len = strcspn(p, delim); 2340 char savech; 2341 2342 savech = p[len]; 2343 p[len] = '\0'; 2344 obj = load_object(p, -1, NULL, 0); 2345 if (obj == NULL) 2346 return -1; /* XXX - cleanup */ 2347 obj->z_interpose = true; 2348 p[len] = savech; 2349 p += len; 2350 p += strspn(p, delim); 2351 } 2352 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2353 return 0; 2354} 2355 2356static const char * 2357printable_path(const char *path) 2358{ 2359 2360 return (path == NULL ? "<unknown>" : path); 2361} 2362 2363/* 2364 * Load a shared object into memory, if it is not already loaded. The 2365 * object may be specified by name or by user-supplied file descriptor 2366 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2367 * duplicate is. 2368 * 2369 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2370 * on failure. 2371 */ 2372static Obj_Entry * 2373load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2374{ 2375 Obj_Entry *obj; 2376 int fd; 2377 struct stat sb; 2378 char *path; 2379 2380 fd = -1; 2381 if (name != NULL) { 2382 TAILQ_FOREACH(obj, &obj_list, next) { 2383 if (obj->marker || obj->doomed) 2384 continue; 2385 if (object_match_name(obj, name)) 2386 return (obj); 2387 } 2388 2389 path = find_library(name, refobj, &fd); 2390 if (path == NULL) 2391 return (NULL); 2392 } else 2393 path = NULL; 2394 2395 if (fd >= 0) { 2396 /* 2397 * search_library_pathfds() opens a fresh file descriptor for the 2398 * library, so there is no need to dup(). 2399 */ 2400 } else if (fd_u == -1) { 2401 /* 2402 * If we didn't find a match by pathname, or the name is not 2403 * supplied, open the file and check again by device and inode. 2404 * This avoids false mismatches caused by multiple links or ".." 2405 * in pathnames. 2406 * 2407 * To avoid a race, we open the file and use fstat() rather than 2408 * using stat(). 2409 */ 2410 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2411 _rtld_error("Cannot open \"%s\"", path); 2412 free(path); 2413 return (NULL); 2414 } 2415 } else { 2416 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2417 if (fd == -1) { 2418 _rtld_error("Cannot dup fd"); 2419 free(path); 2420 return (NULL); 2421 } 2422 } 2423 if (fstat(fd, &sb) == -1) { 2424 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2425 close(fd); 2426 free(path); 2427 return NULL; 2428 } 2429 TAILQ_FOREACH(obj, &obj_list, next) { 2430 if (obj->marker || obj->doomed) 2431 continue; 2432 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2433 break; 2434 } 2435 if (obj != NULL && name != NULL) { 2436 object_add_name(obj, name); 2437 free(path); 2438 close(fd); 2439 return obj; 2440 } 2441 if (flags & RTLD_LO_NOLOAD) { 2442 free(path); 2443 close(fd); 2444 return (NULL); 2445 } 2446 2447 /* First use of this object, so we must map it in */ 2448 obj = do_load_object(fd, name, path, &sb, flags); 2449 if (obj == NULL) 2450 free(path); 2451 close(fd); 2452 2453 return obj; 2454} 2455 2456static Obj_Entry * 2457do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2458 int flags) 2459{ 2460 Obj_Entry *obj; 2461 struct statfs fs; 2462 2463 /* 2464 * but first, make sure that environment variables haven't been 2465 * used to circumvent the noexec flag on a filesystem. 2466 */ 2467 if (dangerous_ld_env) { 2468 if (fstatfs(fd, &fs) != 0) { 2469 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2470 return NULL; 2471 } 2472 if (fs.f_flags & MNT_NOEXEC) { 2473 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2474 return NULL; 2475 } 2476 } 2477 dbg("loading \"%s\"", printable_path(path)); 2478 obj = map_object(fd, printable_path(path), sbp); 2479 if (obj == NULL) 2480 return NULL; 2481 2482 /* 2483 * If DT_SONAME is present in the object, digest_dynamic2 already 2484 * added it to the object names. 2485 */ 2486 if (name != NULL) 2487 object_add_name(obj, name); 2488 obj->path = path; 2489 digest_dynamic(obj, 0); 2490 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2491 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2492 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2493 RTLD_LO_DLOPEN) { 2494 dbg("refusing to load non-loadable \"%s\"", obj->path); 2495 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2496 munmap(obj->mapbase, obj->mapsize); 2497 obj_free(obj); 2498 return (NULL); 2499 } 2500 2501 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2502 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2503 obj_count++; 2504 obj_loads++; 2505 linkmap_add(obj); /* for GDB & dlinfo() */ 2506 max_stack_flags |= obj->stack_flags; 2507 2508 dbg(" %p .. %p: %s", obj->mapbase, 2509 obj->mapbase + obj->mapsize - 1, obj->path); 2510 if (obj->textrel) 2511 dbg(" WARNING: %s has impure text", obj->path); 2512 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2513 obj->path); 2514 2515 return obj; 2516} 2517 2518static Obj_Entry * 2519obj_from_addr(const void *addr) 2520{ 2521 Obj_Entry *obj; 2522 2523 TAILQ_FOREACH(obj, &obj_list, next) { 2524 if (obj->marker) 2525 continue; 2526 if (addr < (void *) obj->mapbase) 2527 continue; 2528 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2529 return obj; 2530 } 2531 return NULL; 2532} 2533 2534static void 2535preinit_main(void) 2536{ 2537 Elf_Addr *preinit_addr; 2538 int index; 2539 2540 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2541 if (preinit_addr == NULL) 2542 return; 2543 2544 for (index = 0; index < obj_main->preinit_array_num; index++) { 2545 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2546 dbg("calling preinit function for %s at %p", obj_main->path, 2547 (void *)preinit_addr[index]); 2548 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2549 0, 0, obj_main->path); 2550 call_init_pointer(obj_main, preinit_addr[index]); 2551 } 2552 } 2553} 2554 2555/* 2556 * Call the finalization functions for each of the objects in "list" 2557 * belonging to the DAG of "root" and referenced once. If NULL "root" 2558 * is specified, every finalization function will be called regardless 2559 * of the reference count and the list elements won't be freed. All of 2560 * the objects are expected to have non-NULL fini functions. 2561 */ 2562static void 2563objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2564{ 2565 Objlist_Entry *elm; 2566 char *saved_msg; 2567 Elf_Addr *fini_addr; 2568 int index; 2569 2570 assert(root == NULL || root->refcount == 1); 2571 2572 if (root != NULL) 2573 root->doomed = true; 2574 2575 /* 2576 * Preserve the current error message since a fini function might 2577 * call into the dynamic linker and overwrite it. 2578 */ 2579 saved_msg = errmsg_save(); 2580 do { 2581 STAILQ_FOREACH(elm, list, link) { 2582 if (root != NULL && (elm->obj->refcount != 1 || 2583 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2584 continue; 2585 /* Remove object from fini list to prevent recursive invocation. */ 2586 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2587 /* Ensure that new references cannot be acquired. */ 2588 elm->obj->doomed = true; 2589 2590 hold_object(elm->obj); 2591 lock_release(rtld_bind_lock, lockstate); 2592 /* 2593 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2594 * When this happens, DT_FINI_ARRAY is processed first. 2595 */ 2596 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2597 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2598 for (index = elm->obj->fini_array_num - 1; index >= 0; 2599 index--) { 2600 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2601 dbg("calling fini function for %s at %p", 2602 elm->obj->path, (void *)fini_addr[index]); 2603 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2604 (void *)fini_addr[index], 0, 0, elm->obj->path); 2605 call_initfini_pointer(elm->obj, fini_addr[index]); 2606 } 2607 } 2608 } 2609 if (elm->obj->fini != (Elf_Addr)NULL) { 2610 dbg("calling fini function for %s at %p", elm->obj->path, 2611 (void *)elm->obj->fini); 2612 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2613 0, 0, elm->obj->path); 2614 call_initfini_pointer(elm->obj, elm->obj->fini); 2615 } 2616 wlock_acquire(rtld_bind_lock, lockstate); 2617 unhold_object(elm->obj); 2618 /* No need to free anything if process is going down. */ 2619 if (root != NULL) 2620 free(elm); 2621 /* 2622 * We must restart the list traversal after every fini call 2623 * because a dlclose() call from the fini function or from 2624 * another thread might have modified the reference counts. 2625 */ 2626 break; 2627 } 2628 } while (elm != NULL); 2629 errmsg_restore(saved_msg); 2630} 2631 2632/* 2633 * Call the initialization functions for each of the objects in 2634 * "list". All of the objects are expected to have non-NULL init 2635 * functions. 2636 */ 2637static void 2638objlist_call_init(Objlist *list, RtldLockState *lockstate) 2639{ 2640 Objlist_Entry *elm; 2641 Obj_Entry *obj; 2642 char *saved_msg; 2643 Elf_Addr *init_addr; 2644 int index; 2645 2646 /* 2647 * Clean init_scanned flag so that objects can be rechecked and 2648 * possibly initialized earlier if any of vectors called below 2649 * cause the change by using dlopen. 2650 */ 2651 TAILQ_FOREACH(obj, &obj_list, next) { 2652 if (obj->marker) 2653 continue; 2654 obj->init_scanned = false; 2655 } 2656 2657 /* 2658 * Preserve the current error message since an init function might 2659 * call into the dynamic linker and overwrite it. 2660 */ 2661 saved_msg = errmsg_save(); 2662 STAILQ_FOREACH(elm, list, link) { 2663 if (elm->obj->init_done) /* Initialized early. */ 2664 continue; 2665 /* 2666 * Race: other thread might try to use this object before current 2667 * one completes the initialization. Not much can be done here 2668 * without better locking. 2669 */ 2670 elm->obj->init_done = true; 2671 hold_object(elm->obj); 2672 lock_release(rtld_bind_lock, lockstate); 2673 2674 /* 2675 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2676 * When this happens, DT_INIT is processed first. 2677 */ 2678 if (elm->obj->init != (Elf_Addr)NULL) { 2679 dbg("calling init function for %s at %p", elm->obj->path, 2680 (void *)elm->obj->init); 2681 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2682 0, 0, elm->obj->path); 2683 call_initfini_pointer(elm->obj, elm->obj->init); 2684 } 2685 init_addr = (Elf_Addr *)elm->obj->init_array; 2686 if (init_addr != NULL) { 2687 for (index = 0; index < elm->obj->init_array_num; index++) { 2688 if (init_addr[index] != 0 && init_addr[index] != 1) { 2689 dbg("calling init function for %s at %p", elm->obj->path, 2690 (void *)init_addr[index]); 2691 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2692 (void *)init_addr[index], 0, 0, elm->obj->path); 2693 call_init_pointer(elm->obj, init_addr[index]); 2694 } 2695 } 2696 } 2697 wlock_acquire(rtld_bind_lock, lockstate); 2698 unhold_object(elm->obj); 2699 } 2700 errmsg_restore(saved_msg); 2701} 2702 2703static void 2704objlist_clear(Objlist *list) 2705{ 2706 Objlist_Entry *elm; 2707 2708 while (!STAILQ_EMPTY(list)) { 2709 elm = STAILQ_FIRST(list); 2710 STAILQ_REMOVE_HEAD(list, link); 2711 free(elm); 2712 } 2713} 2714 2715static Objlist_Entry * 2716objlist_find(Objlist *list, const Obj_Entry *obj) 2717{ 2718 Objlist_Entry *elm; 2719 2720 STAILQ_FOREACH(elm, list, link) 2721 if (elm->obj == obj) 2722 return elm; 2723 return NULL; 2724} 2725 2726static void 2727objlist_init(Objlist *list) 2728{ 2729 STAILQ_INIT(list); 2730} 2731 2732static void 2733objlist_push_head(Objlist *list, Obj_Entry *obj) 2734{ 2735 Objlist_Entry *elm; 2736 2737 elm = NEW(Objlist_Entry); 2738 elm->obj = obj; 2739 STAILQ_INSERT_HEAD(list, elm, link); 2740} 2741 2742static void 2743objlist_push_tail(Objlist *list, Obj_Entry *obj) 2744{ 2745 Objlist_Entry *elm; 2746 2747 elm = NEW(Objlist_Entry); 2748 elm->obj = obj; 2749 STAILQ_INSERT_TAIL(list, elm, link); 2750} 2751 2752static void 2753objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2754{ 2755 Objlist_Entry *elm, *listelm; 2756 2757 STAILQ_FOREACH(listelm, list, link) { 2758 if (listelm->obj == listobj) 2759 break; 2760 } 2761 elm = NEW(Objlist_Entry); 2762 elm->obj = obj; 2763 if (listelm != NULL) 2764 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2765 else 2766 STAILQ_INSERT_TAIL(list, elm, link); 2767} 2768 2769static void 2770objlist_remove(Objlist *list, Obj_Entry *obj) 2771{ 2772 Objlist_Entry *elm; 2773 2774 if ((elm = objlist_find(list, obj)) != NULL) { 2775 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2776 free(elm); 2777 } 2778} 2779 2780/* 2781 * Relocate dag rooted in the specified object. 2782 * Returns 0 on success, or -1 on failure. 2783 */ 2784 2785static int 2786relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2787 int flags, RtldLockState *lockstate) 2788{ 2789 Objlist_Entry *elm; 2790 int error; 2791 2792 error = 0; 2793 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2794 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2795 lockstate); 2796 if (error == -1) 2797 break; 2798 } 2799 return (error); 2800} 2801 2802/* 2803 * Prepare for, or clean after, relocating an object marked with 2804 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2805 * segments are remapped read-write. After relocations are done, the 2806 * segment's permissions are returned back to the modes specified in 2807 * the phdrs. If any relocation happened, or always for wired 2808 * program, COW is triggered. 2809 */ 2810static int 2811reloc_textrel_prot(Obj_Entry *obj, bool before) 2812{ 2813 const Elf_Phdr *ph; 2814 void *base; 2815 size_t l, sz; 2816 int prot; 2817 2818 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2819 l--, ph++) { 2820 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2821 continue; 2822 base = obj->relocbase + trunc_page(ph->p_vaddr); 2823 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2824 trunc_page(ph->p_vaddr); 2825 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2826 if (mprotect(base, sz, prot) == -1) { 2827 _rtld_error("%s: Cannot write-%sable text segment: %s", 2828 obj->path, before ? "en" : "dis", 2829 rtld_strerror(errno)); 2830 return (-1); 2831 } 2832 } 2833 return (0); 2834} 2835 2836/* 2837 * Relocate single object. 2838 * Returns 0 on success, or -1 on failure. 2839 */ 2840static int 2841relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2842 int flags, RtldLockState *lockstate) 2843{ 2844 2845 if (obj->relocated) 2846 return (0); 2847 obj->relocated = true; 2848 if (obj != rtldobj) 2849 dbg("relocating \"%s\"", obj->path); 2850 2851 if (obj->symtab == NULL || obj->strtab == NULL || 2852 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2853 _rtld_error("%s: Shared object has no run-time symbol table", 2854 obj->path); 2855 return (-1); 2856 } 2857 2858 /* There are relocations to the write-protected text segment. */ 2859 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2860 return (-1); 2861 2862 /* Process the non-PLT non-IFUNC relocations. */ 2863 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2864 return (-1); 2865 2866 /* Re-protected the text segment. */ 2867 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2868 return (-1); 2869 2870 /* Set the special PLT or GOT entries. */ 2871 init_pltgot(obj); 2872 2873 /* Process the PLT relocations. */ 2874 if (reloc_plt(obj) == -1) 2875 return (-1); 2876 /* Relocate the jump slots if we are doing immediate binding. */ 2877 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2878 lockstate) == -1) 2879 return (-1); 2880 2881 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2882 return (-1); 2883 2884 /* 2885 * Set up the magic number and version in the Obj_Entry. These 2886 * were checked in the crt1.o from the original ElfKit, so we 2887 * set them for backward compatibility. 2888 */ 2889 obj->magic = RTLD_MAGIC; 2890 obj->version = RTLD_VERSION; 2891 2892 return (0); 2893} 2894 2895/* 2896 * Relocate newly-loaded shared objects. The argument is a pointer to 2897 * the Obj_Entry for the first such object. All objects from the first 2898 * to the end of the list of objects are relocated. Returns 0 on success, 2899 * or -1 on failure. 2900 */ 2901static int 2902relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2903 int flags, RtldLockState *lockstate) 2904{ 2905 Obj_Entry *obj; 2906 int error; 2907 2908 for (error = 0, obj = first; obj != NULL; 2909 obj = TAILQ_NEXT(obj, next)) { 2910 if (obj->marker) 2911 continue; 2912 error = relocate_object(obj, bind_now, rtldobj, flags, 2913 lockstate); 2914 if (error == -1) 2915 break; 2916 } 2917 return (error); 2918} 2919 2920/* 2921 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2922 * referencing STT_GNU_IFUNC symbols is postponed till the other 2923 * relocations are done. The indirect functions specified as 2924 * ifunc are allowed to call other symbols, so we need to have 2925 * objects relocated before asking for resolution from indirects. 2926 * 2927 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2928 * instead of the usual lazy handling of PLT slots. It is 2929 * consistent with how GNU does it. 2930 */ 2931static int 2932resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2933 RtldLockState *lockstate) 2934{ 2935 2936 if (obj->ifuncs_resolved) 2937 return (0); 2938 obj->ifuncs_resolved = true; 2939 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 2940 return (0); 2941 if (obj_disable_relro(obj) == -1 || 2942 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 2943 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2944 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 2945 obj_enforce_relro(obj) == -1) 2946 return (-1); 2947 return (0); 2948} 2949 2950static int 2951initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2952 RtldLockState *lockstate) 2953{ 2954 Objlist_Entry *elm; 2955 Obj_Entry *obj; 2956 2957 STAILQ_FOREACH(elm, list, link) { 2958 obj = elm->obj; 2959 if (obj->marker) 2960 continue; 2961 if (resolve_object_ifunc(obj, bind_now, flags, 2962 lockstate) == -1) 2963 return (-1); 2964 } 2965 return (0); 2966} 2967 2968/* 2969 * Cleanup procedure. It will be called (by the atexit mechanism) just 2970 * before the process exits. 2971 */ 2972static void 2973rtld_exit(void) 2974{ 2975 RtldLockState lockstate; 2976 2977 wlock_acquire(rtld_bind_lock, &lockstate); 2978 dbg("rtld_exit()"); 2979 objlist_call_fini(&list_fini, NULL, &lockstate); 2980 /* No need to remove the items from the list, since we are exiting. */ 2981 if (!libmap_disable) 2982 lm_fini(); 2983 lock_release(rtld_bind_lock, &lockstate); 2984} 2985 2986/* 2987 * Iterate over a search path, translate each element, and invoke the 2988 * callback on the result. 2989 */ 2990static void * 2991path_enumerate(const char *path, path_enum_proc callback, 2992 const char *refobj_path, void *arg) 2993{ 2994 const char *trans; 2995 if (path == NULL) 2996 return (NULL); 2997 2998 path += strspn(path, ":;"); 2999 while (*path != '\0') { 3000 size_t len; 3001 char *res; 3002 3003 len = strcspn(path, ":;"); 3004 trans = lm_findn(refobj_path, path, len); 3005 if (trans) 3006 res = callback(trans, strlen(trans), arg); 3007 else 3008 res = callback(path, len, arg); 3009 3010 if (res != NULL) 3011 return (res); 3012 3013 path += len; 3014 path += strspn(path, ":;"); 3015 } 3016 3017 return (NULL); 3018} 3019 3020struct try_library_args { 3021 const char *name; 3022 size_t namelen; 3023 char *buffer; 3024 size_t buflen; 3025 int fd; 3026}; 3027 3028static void * 3029try_library_path(const char *dir, size_t dirlen, void *param) 3030{ 3031 struct try_library_args *arg; 3032 int fd; 3033 3034 arg = param; 3035 if (*dir == '/' || trust) { 3036 char *pathname; 3037 3038 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3039 return (NULL); 3040 3041 pathname = arg->buffer; 3042 strncpy(pathname, dir, dirlen); 3043 pathname[dirlen] = '/'; 3044 strcpy(pathname + dirlen + 1, arg->name); 3045 3046 dbg(" Trying \"%s\"", pathname); 3047 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3048 if (fd >= 0) { 3049 dbg(" Opened \"%s\", fd %d", pathname, fd); 3050 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3051 strcpy(pathname, arg->buffer); 3052 arg->fd = fd; 3053 return (pathname); 3054 } else { 3055 dbg(" Failed to open \"%s\": %s", 3056 pathname, rtld_strerror(errno)); 3057 } 3058 } 3059 return (NULL); 3060} 3061 3062static char * 3063search_library_path(const char *name, const char *path, 3064 const char *refobj_path, int *fdp) 3065{ 3066 char *p; 3067 struct try_library_args arg; 3068 3069 if (path == NULL) 3070 return NULL; 3071 3072 arg.name = name; 3073 arg.namelen = strlen(name); 3074 arg.buffer = xmalloc(PATH_MAX); 3075 arg.buflen = PATH_MAX; 3076 arg.fd = -1; 3077 3078 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3079 *fdp = arg.fd; 3080 3081 free(arg.buffer); 3082 3083 return (p); 3084} 3085 3086 3087/* 3088 * Finds the library with the given name using the directory descriptors 3089 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3090 * 3091 * Returns a freshly-opened close-on-exec file descriptor for the library, 3092 * or -1 if the library cannot be found. 3093 */ 3094static char * 3095search_library_pathfds(const char *name, const char *path, int *fdp) 3096{ 3097 char *envcopy, *fdstr, *found, *last_token; 3098 size_t len; 3099 int dirfd, fd; 3100 3101 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3102 3103 /* Don't load from user-specified libdirs into setuid binaries. */ 3104 if (!trust) 3105 return (NULL); 3106 3107 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3108 if (path == NULL) 3109 return (NULL); 3110 3111 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3112 if (name[0] == '/') { 3113 dbg("Absolute path (%s) passed to %s", name, __func__); 3114 return (NULL); 3115 } 3116 3117 /* 3118 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3119 * copy of the path, as strtok_r rewrites separator tokens 3120 * with '\0'. 3121 */ 3122 found = NULL; 3123 envcopy = xstrdup(path); 3124 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3125 fdstr = strtok_r(NULL, ":", &last_token)) { 3126 dirfd = parse_integer(fdstr); 3127 if (dirfd < 0) { 3128 _rtld_error("failed to parse directory FD: '%s'", 3129 fdstr); 3130 break; 3131 } 3132 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3133 if (fd >= 0) { 3134 *fdp = fd; 3135 len = strlen(fdstr) + strlen(name) + 3; 3136 found = xmalloc(len); 3137 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3138 _rtld_error("error generating '%d/%s'", 3139 dirfd, name); 3140 rtld_die(); 3141 } 3142 dbg("open('%s') => %d", found, fd); 3143 break; 3144 } 3145 } 3146 free(envcopy); 3147 3148 return (found); 3149} 3150 3151 3152int 3153dlclose(void *handle) 3154{ 3155 RtldLockState lockstate; 3156 int error; 3157 3158 wlock_acquire(rtld_bind_lock, &lockstate); 3159 error = dlclose_locked(handle, &lockstate); 3160 lock_release(rtld_bind_lock, &lockstate); 3161 return (error); 3162} 3163 3164static int 3165dlclose_locked(void *handle, RtldLockState *lockstate) 3166{ 3167 Obj_Entry *root; 3168 3169 root = dlcheck(handle); 3170 if (root == NULL) 3171 return -1; 3172 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3173 root->path); 3174 3175 /* Unreference the object and its dependencies. */ 3176 root->dl_refcount--; 3177 3178 if (root->refcount == 1) { 3179 /* 3180 * The object will be no longer referenced, so we must unload it. 3181 * First, call the fini functions. 3182 */ 3183 objlist_call_fini(&list_fini, root, lockstate); 3184 3185 unref_dag(root); 3186 3187 /* Finish cleaning up the newly-unreferenced objects. */ 3188 GDB_STATE(RT_DELETE,&root->linkmap); 3189 unload_object(root, lockstate); 3190 GDB_STATE(RT_CONSISTENT,NULL); 3191 } else 3192 unref_dag(root); 3193 3194 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3195 return 0; 3196} 3197 3198char * 3199dlerror(void) 3200{ 3201 char *msg = error_message; 3202 error_message = NULL; 3203 return msg; 3204} 3205 3206/* 3207 * This function is deprecated and has no effect. 3208 */ 3209void 3210dllockinit(void *context, 3211 void *(*lock_create)(void *context), 3212 void (*rlock_acquire)(void *lock), 3213 void (*wlock_acquire)(void *lock), 3214 void (*lock_release)(void *lock), 3215 void (*lock_destroy)(void *lock), 3216 void (*context_destroy)(void *context)) 3217{ 3218 static void *cur_context; 3219 static void (*cur_context_destroy)(void *); 3220 3221 /* Just destroy the context from the previous call, if necessary. */ 3222 if (cur_context_destroy != NULL) 3223 cur_context_destroy(cur_context); 3224 cur_context = context; 3225 cur_context_destroy = context_destroy; 3226} 3227 3228void * 3229dlopen(const char *name, int mode) 3230{ 3231 3232 return (rtld_dlopen(name, -1, mode)); 3233} 3234 3235void * 3236fdlopen(int fd, int mode) 3237{ 3238 3239 return (rtld_dlopen(NULL, fd, mode)); 3240} 3241 3242static void * 3243rtld_dlopen(const char *name, int fd, int mode) 3244{ 3245 RtldLockState lockstate; 3246 int lo_flags; 3247 3248 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3249 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3250 if (ld_tracing != NULL) { 3251 rlock_acquire(rtld_bind_lock, &lockstate); 3252 if (sigsetjmp(lockstate.env, 0) != 0) 3253 lock_upgrade(rtld_bind_lock, &lockstate); 3254 environ = (char **)*get_program_var_addr("environ", &lockstate); 3255 lock_release(rtld_bind_lock, &lockstate); 3256 } 3257 lo_flags = RTLD_LO_DLOPEN; 3258 if (mode & RTLD_NODELETE) 3259 lo_flags |= RTLD_LO_NODELETE; 3260 if (mode & RTLD_NOLOAD) 3261 lo_flags |= RTLD_LO_NOLOAD; 3262 if (ld_tracing != NULL) 3263 lo_flags |= RTLD_LO_TRACE; 3264 3265 return (dlopen_object(name, fd, obj_main, lo_flags, 3266 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3267} 3268 3269static void 3270dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3271{ 3272 3273 obj->dl_refcount--; 3274 unref_dag(obj); 3275 if (obj->refcount == 0) 3276 unload_object(obj, lockstate); 3277} 3278 3279static Obj_Entry * 3280dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3281 int mode, RtldLockState *lockstate) 3282{ 3283 Obj_Entry *old_obj_tail; 3284 Obj_Entry *obj; 3285 Objlist initlist; 3286 RtldLockState mlockstate; 3287 int result; 3288 3289 objlist_init(&initlist); 3290 3291 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3292 wlock_acquire(rtld_bind_lock, &mlockstate); 3293 lockstate = &mlockstate; 3294 } 3295 GDB_STATE(RT_ADD,NULL); 3296 3297 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3298 obj = NULL; 3299 if (name == NULL && fd == -1) { 3300 obj = obj_main; 3301 obj->refcount++; 3302 } else { 3303 obj = load_object(name, fd, refobj, lo_flags); 3304 } 3305 3306 if (obj) { 3307 obj->dl_refcount++; 3308 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3309 objlist_push_tail(&list_global, obj); 3310 if (globallist_next(old_obj_tail) != NULL) { 3311 /* We loaded something new. */ 3312 assert(globallist_next(old_obj_tail) == obj); 3313 result = 0; 3314 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3315 !allocate_tls_offset(obj)) { 3316 _rtld_error("%s: No space available " 3317 "for static Thread Local Storage", obj->path); 3318 result = -1; 3319 } 3320 if (result != -1) 3321 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3322 RTLD_LO_EARLY)); 3323 init_dag(obj); 3324 ref_dag(obj); 3325 if (result != -1) 3326 result = rtld_verify_versions(&obj->dagmembers); 3327 if (result != -1 && ld_tracing) 3328 goto trace; 3329 if (result == -1 || relocate_object_dag(obj, 3330 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3331 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3332 lockstate) == -1) { 3333 dlopen_cleanup(obj, lockstate); 3334 obj = NULL; 3335 } else if (lo_flags & RTLD_LO_EARLY) { 3336 /* 3337 * Do not call the init functions for early loaded 3338 * filtees. The image is still not initialized enough 3339 * for them to work. 3340 * 3341 * Our object is found by the global object list and 3342 * will be ordered among all init calls done right 3343 * before transferring control to main. 3344 */ 3345 } else { 3346 /* Make list of init functions to call. */ 3347 initlist_add_objects(obj, obj, &initlist); 3348 } 3349 /* 3350 * Process all no_delete or global objects here, given 3351 * them own DAGs to prevent their dependencies from being 3352 * unloaded. This has to be done after we have loaded all 3353 * of the dependencies, so that we do not miss any. 3354 */ 3355 if (obj != NULL) 3356 process_z(obj); 3357 } else { 3358 /* 3359 * Bump the reference counts for objects on this DAG. If 3360 * this is the first dlopen() call for the object that was 3361 * already loaded as a dependency, initialize the dag 3362 * starting at it. 3363 */ 3364 init_dag(obj); 3365 ref_dag(obj); 3366 3367 if ((lo_flags & RTLD_LO_TRACE) != 0) 3368 goto trace; 3369 } 3370 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3371 obj->z_nodelete) && !obj->ref_nodel) { 3372 dbg("obj %s nodelete", obj->path); 3373 ref_dag(obj); 3374 obj->z_nodelete = obj->ref_nodel = true; 3375 } 3376 } 3377 3378 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3379 name); 3380 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3381 3382 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3383 map_stacks_exec(lockstate); 3384 if (obj != NULL) 3385 distribute_static_tls(&initlist, lockstate); 3386 } 3387 3388 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3389 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3390 lockstate) == -1) { 3391 objlist_clear(&initlist); 3392 dlopen_cleanup(obj, lockstate); 3393 if (lockstate == &mlockstate) 3394 lock_release(rtld_bind_lock, lockstate); 3395 return (NULL); 3396 } 3397 3398 if (!(lo_flags & RTLD_LO_EARLY)) { 3399 /* Call the init functions. */ 3400 objlist_call_init(&initlist, lockstate); 3401 } 3402 objlist_clear(&initlist); 3403 if (lockstate == &mlockstate) 3404 lock_release(rtld_bind_lock, lockstate); 3405 return obj; 3406trace: 3407 trace_loaded_objects(obj); 3408 if (lockstate == &mlockstate) 3409 lock_release(rtld_bind_lock, lockstate); 3410 exit(0); 3411} 3412 3413static void * 3414do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3415 int flags) 3416{ 3417 DoneList donelist; 3418 const Obj_Entry *obj, *defobj; 3419 const Elf_Sym *def; 3420 SymLook req; 3421 RtldLockState lockstate; 3422 tls_index ti; 3423 void *sym; 3424 int res; 3425 3426 def = NULL; 3427 defobj = NULL; 3428 symlook_init(&req, name); 3429 req.ventry = ve; 3430 req.flags = flags | SYMLOOK_IN_PLT; 3431 req.lockstate = &lockstate; 3432 3433 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3434 rlock_acquire(rtld_bind_lock, &lockstate); 3435 if (sigsetjmp(lockstate.env, 0) != 0) 3436 lock_upgrade(rtld_bind_lock, &lockstate); 3437 if (handle == NULL || handle == RTLD_NEXT || 3438 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3439 3440 if ((obj = obj_from_addr(retaddr)) == NULL) { 3441 _rtld_error("Cannot determine caller's shared object"); 3442 lock_release(rtld_bind_lock, &lockstate); 3443 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3444 return NULL; 3445 } 3446 if (handle == NULL) { /* Just the caller's shared object. */ 3447 res = symlook_obj(&req, obj); 3448 if (res == 0) { 3449 def = req.sym_out; 3450 defobj = req.defobj_out; 3451 } 3452 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3453 handle == RTLD_SELF) { /* ... caller included */ 3454 if (handle == RTLD_NEXT) 3455 obj = globallist_next(obj); 3456 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3457 if (obj->marker) 3458 continue; 3459 res = symlook_obj(&req, obj); 3460 if (res == 0) { 3461 if (def == NULL || 3462 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3463 def = req.sym_out; 3464 defobj = req.defobj_out; 3465 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3466 break; 3467 } 3468 } 3469 } 3470 /* 3471 * Search the dynamic linker itself, and possibly resolve the 3472 * symbol from there. This is how the application links to 3473 * dynamic linker services such as dlopen. 3474 */ 3475 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3476 res = symlook_obj(&req, &obj_rtld); 3477 if (res == 0) { 3478 def = req.sym_out; 3479 defobj = req.defobj_out; 3480 } 3481 } 3482 } else { 3483 assert(handle == RTLD_DEFAULT); 3484 res = symlook_default(&req, obj); 3485 if (res == 0) { 3486 defobj = req.defobj_out; 3487 def = req.sym_out; 3488 } 3489 } 3490 } else { 3491 if ((obj = dlcheck(handle)) == NULL) { 3492 lock_release(rtld_bind_lock, &lockstate); 3493 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3494 return NULL; 3495 } 3496 3497 donelist_init(&donelist); 3498 if (obj->mainprog) { 3499 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3500 res = symlook_global(&req, &donelist); 3501 if (res == 0) { 3502 def = req.sym_out; 3503 defobj = req.defobj_out; 3504 } 3505 /* 3506 * Search the dynamic linker itself, and possibly resolve the 3507 * symbol from there. This is how the application links to 3508 * dynamic linker services such as dlopen. 3509 */ 3510 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3511 res = symlook_obj(&req, &obj_rtld); 3512 if (res == 0) { 3513 def = req.sym_out; 3514 defobj = req.defobj_out; 3515 } 3516 } 3517 } 3518 else { 3519 /* Search the whole DAG rooted at the given object. */ 3520 res = symlook_list(&req, &obj->dagmembers, &donelist); 3521 if (res == 0) { 3522 def = req.sym_out; 3523 defobj = req.defobj_out; 3524 } 3525 } 3526 } 3527 3528 if (def != NULL) { 3529 lock_release(rtld_bind_lock, &lockstate); 3530 3531 /* 3532 * The value required by the caller is derived from the value 3533 * of the symbol. this is simply the relocated value of the 3534 * symbol. 3535 */ 3536 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3537 sym = make_function_pointer(def, defobj); 3538 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3539 sym = rtld_resolve_ifunc(defobj, def); 3540 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3541 ti.ti_module = defobj->tlsindex; 3542 ti.ti_offset = def->st_value; 3543 sym = __tls_get_addr(&ti); 3544 } else 3545 sym = defobj->relocbase + def->st_value; 3546 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3547 return (sym); 3548 } 3549 3550 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3551 ve != NULL ? ve->name : ""); 3552 lock_release(rtld_bind_lock, &lockstate); 3553 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3554 return NULL; 3555} 3556 3557void * 3558dlsym(void *handle, const char *name) 3559{ 3560 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3561 SYMLOOK_DLSYM); 3562} 3563 3564dlfunc_t 3565dlfunc(void *handle, const char *name) 3566{ 3567 union { 3568 void *d; 3569 dlfunc_t f; 3570 } rv; 3571 3572 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3573 SYMLOOK_DLSYM); 3574 return (rv.f); 3575} 3576 3577void * 3578dlvsym(void *handle, const char *name, const char *version) 3579{ 3580 Ver_Entry ventry; 3581 3582 ventry.name = version; 3583 ventry.file = NULL; 3584 ventry.hash = elf_hash(version); 3585 ventry.flags= 0; 3586 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3587 SYMLOOK_DLSYM); 3588} 3589 3590int 3591_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3592{ 3593 const Obj_Entry *obj; 3594 RtldLockState lockstate; 3595 3596 rlock_acquire(rtld_bind_lock, &lockstate); 3597 obj = obj_from_addr(addr); 3598 if (obj == NULL) { 3599 _rtld_error("No shared object contains address"); 3600 lock_release(rtld_bind_lock, &lockstate); 3601 return (0); 3602 } 3603 rtld_fill_dl_phdr_info(obj, phdr_info); 3604 lock_release(rtld_bind_lock, &lockstate); 3605 return (1); 3606} 3607 3608int 3609dladdr(const void *addr, Dl_info *info) 3610{ 3611 const Obj_Entry *obj; 3612 const Elf_Sym *def; 3613 void *symbol_addr; 3614 unsigned long symoffset; 3615 RtldLockState lockstate; 3616 3617 rlock_acquire(rtld_bind_lock, &lockstate); 3618 obj = obj_from_addr(addr); 3619 if (obj == NULL) { 3620 _rtld_error("No shared object contains address"); 3621 lock_release(rtld_bind_lock, &lockstate); 3622 return 0; 3623 } 3624 info->dli_fname = obj->path; 3625 info->dli_fbase = obj->mapbase; 3626 info->dli_saddr = (void *)0; 3627 info->dli_sname = NULL; 3628 3629 /* 3630 * Walk the symbol list looking for the symbol whose address is 3631 * closest to the address sent in. 3632 */ 3633 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3634 def = obj->symtab + symoffset; 3635 3636 /* 3637 * For skip the symbol if st_shndx is either SHN_UNDEF or 3638 * SHN_COMMON. 3639 */ 3640 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3641 continue; 3642 3643 /* 3644 * If the symbol is greater than the specified address, or if it 3645 * is further away from addr than the current nearest symbol, 3646 * then reject it. 3647 */ 3648 symbol_addr = obj->relocbase + def->st_value; 3649 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3650 continue; 3651 3652 /* Update our idea of the nearest symbol. */ 3653 info->dli_sname = obj->strtab + def->st_name; 3654 info->dli_saddr = symbol_addr; 3655 3656 /* Exact match? */ 3657 if (info->dli_saddr == addr) 3658 break; 3659 } 3660 lock_release(rtld_bind_lock, &lockstate); 3661 return 1; 3662} 3663 3664int 3665dlinfo(void *handle, int request, void *p) 3666{ 3667 const Obj_Entry *obj; 3668 RtldLockState lockstate; 3669 int error; 3670 3671 rlock_acquire(rtld_bind_lock, &lockstate); 3672 3673 if (handle == NULL || handle == RTLD_SELF) { 3674 void *retaddr; 3675 3676 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3677 if ((obj = obj_from_addr(retaddr)) == NULL) 3678 _rtld_error("Cannot determine caller's shared object"); 3679 } else 3680 obj = dlcheck(handle); 3681 3682 if (obj == NULL) { 3683 lock_release(rtld_bind_lock, &lockstate); 3684 return (-1); 3685 } 3686 3687 error = 0; 3688 switch (request) { 3689 case RTLD_DI_LINKMAP: 3690 *((struct link_map const **)p) = &obj->linkmap; 3691 break; 3692 case RTLD_DI_ORIGIN: 3693 error = rtld_dirname(obj->path, p); 3694 break; 3695 3696 case RTLD_DI_SERINFOSIZE: 3697 case RTLD_DI_SERINFO: 3698 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3699 break; 3700 3701 default: 3702 _rtld_error("Invalid request %d passed to dlinfo()", request); 3703 error = -1; 3704 } 3705 3706 lock_release(rtld_bind_lock, &lockstate); 3707 3708 return (error); 3709} 3710 3711static void 3712rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3713{ 3714 3715 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3716 phdr_info->dlpi_name = obj->path; 3717 phdr_info->dlpi_phdr = obj->phdr; 3718 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3719 phdr_info->dlpi_tls_modid = obj->tlsindex; 3720 phdr_info->dlpi_tls_data = obj->tlsinit; 3721 phdr_info->dlpi_adds = obj_loads; 3722 phdr_info->dlpi_subs = obj_loads - obj_count; 3723} 3724 3725int 3726dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3727{ 3728 struct dl_phdr_info phdr_info; 3729 Obj_Entry *obj, marker; 3730 RtldLockState bind_lockstate, phdr_lockstate; 3731 int error; 3732 3733 init_marker(&marker); 3734 error = 0; 3735 3736 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3737 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3738 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3739 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3740 rtld_fill_dl_phdr_info(obj, &phdr_info); 3741 hold_object(obj); 3742 lock_release(rtld_bind_lock, &bind_lockstate); 3743 3744 error = callback(&phdr_info, sizeof phdr_info, param); 3745 3746 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3747 unhold_object(obj); 3748 obj = globallist_next(&marker); 3749 TAILQ_REMOVE(&obj_list, &marker, next); 3750 if (error != 0) { 3751 lock_release(rtld_bind_lock, &bind_lockstate); 3752 lock_release(rtld_phdr_lock, &phdr_lockstate); 3753 return (error); 3754 } 3755 } 3756 3757 if (error == 0) { 3758 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3759 lock_release(rtld_bind_lock, &bind_lockstate); 3760 error = callback(&phdr_info, sizeof(phdr_info), param); 3761 } 3762 lock_release(rtld_phdr_lock, &phdr_lockstate); 3763 return (error); 3764} 3765 3766static void * 3767fill_search_info(const char *dir, size_t dirlen, void *param) 3768{ 3769 struct fill_search_info_args *arg; 3770 3771 arg = param; 3772 3773 if (arg->request == RTLD_DI_SERINFOSIZE) { 3774 arg->serinfo->dls_cnt ++; 3775 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3776 } else { 3777 struct dl_serpath *s_entry; 3778 3779 s_entry = arg->serpath; 3780 s_entry->dls_name = arg->strspace; 3781 s_entry->dls_flags = arg->flags; 3782 3783 strncpy(arg->strspace, dir, dirlen); 3784 arg->strspace[dirlen] = '\0'; 3785 3786 arg->strspace += dirlen + 1; 3787 arg->serpath++; 3788 } 3789 3790 return (NULL); 3791} 3792 3793static int 3794do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3795{ 3796 struct dl_serinfo _info; 3797 struct fill_search_info_args args; 3798 3799 args.request = RTLD_DI_SERINFOSIZE; 3800 args.serinfo = &_info; 3801 3802 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3803 _info.dls_cnt = 0; 3804 3805 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3806 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3807 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3808 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3809 if (!obj->z_nodeflib) 3810 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3811 3812 3813 if (request == RTLD_DI_SERINFOSIZE) { 3814 info->dls_size = _info.dls_size; 3815 info->dls_cnt = _info.dls_cnt; 3816 return (0); 3817 } 3818 3819 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3820 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3821 return (-1); 3822 } 3823 3824 args.request = RTLD_DI_SERINFO; 3825 args.serinfo = info; 3826 args.serpath = &info->dls_serpath[0]; 3827 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3828 3829 args.flags = LA_SER_RUNPATH; 3830 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3831 return (-1); 3832 3833 args.flags = LA_SER_LIBPATH; 3834 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3835 return (-1); 3836 3837 args.flags = LA_SER_RUNPATH; 3838 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3839 return (-1); 3840 3841 args.flags = LA_SER_CONFIG; 3842 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3843 != NULL) 3844 return (-1); 3845 3846 args.flags = LA_SER_DEFAULT; 3847 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3848 fill_search_info, NULL, &args) != NULL) 3849 return (-1); 3850 return (0); 3851} 3852 3853static int 3854rtld_dirname(const char *path, char *bname) 3855{ 3856 const char *endp; 3857 3858 /* Empty or NULL string gets treated as "." */ 3859 if (path == NULL || *path == '\0') { 3860 bname[0] = '.'; 3861 bname[1] = '\0'; 3862 return (0); 3863 } 3864 3865 /* Strip trailing slashes */ 3866 endp = path + strlen(path) - 1; 3867 while (endp > path && *endp == '/') 3868 endp--; 3869 3870 /* Find the start of the dir */ 3871 while (endp > path && *endp != '/') 3872 endp--; 3873 3874 /* Either the dir is "/" or there are no slashes */ 3875 if (endp == path) { 3876 bname[0] = *endp == '/' ? '/' : '.'; 3877 bname[1] = '\0'; 3878 return (0); 3879 } else { 3880 do { 3881 endp--; 3882 } while (endp > path && *endp == '/'); 3883 } 3884 3885 if (endp - path + 2 > PATH_MAX) 3886 { 3887 _rtld_error("Filename is too long: %s", path); 3888 return(-1); 3889 } 3890 3891 strncpy(bname, path, endp - path + 1); 3892 bname[endp - path + 1] = '\0'; 3893 return (0); 3894} 3895 3896static int 3897rtld_dirname_abs(const char *path, char *base) 3898{ 3899 char *last; 3900 3901 if (realpath(path, base) == NULL) 3902 return (-1); 3903 dbg("%s -> %s", path, base); 3904 last = strrchr(base, '/'); 3905 if (last == NULL) 3906 return (-1); 3907 if (last != base) 3908 *last = '\0'; 3909 return (0); 3910} 3911 3912static void 3913linkmap_add(Obj_Entry *obj) 3914{ 3915 struct link_map *l = &obj->linkmap; 3916 struct link_map *prev; 3917 3918 obj->linkmap.l_name = obj->path; 3919 obj->linkmap.l_addr = obj->mapbase; 3920 obj->linkmap.l_ld = obj->dynamic; 3921#ifdef __mips__ 3922 /* GDB needs load offset on MIPS to use the symbols */ 3923 obj->linkmap.l_offs = obj->relocbase; 3924#endif 3925 3926 if (r_debug.r_map == NULL) { 3927 r_debug.r_map = l; 3928 return; 3929 } 3930 3931 /* 3932 * Scan to the end of the list, but not past the entry for the 3933 * dynamic linker, which we want to keep at the very end. 3934 */ 3935 for (prev = r_debug.r_map; 3936 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3937 prev = prev->l_next) 3938 ; 3939 3940 /* Link in the new entry. */ 3941 l->l_prev = prev; 3942 l->l_next = prev->l_next; 3943 if (l->l_next != NULL) 3944 l->l_next->l_prev = l; 3945 prev->l_next = l; 3946} 3947 3948static void 3949linkmap_delete(Obj_Entry *obj) 3950{ 3951 struct link_map *l = &obj->linkmap; 3952 3953 if (l->l_prev == NULL) { 3954 if ((r_debug.r_map = l->l_next) != NULL) 3955 l->l_next->l_prev = NULL; 3956 return; 3957 } 3958 3959 if ((l->l_prev->l_next = l->l_next) != NULL) 3960 l->l_next->l_prev = l->l_prev; 3961} 3962 3963/* 3964 * Function for the debugger to set a breakpoint on to gain control. 3965 * 3966 * The two parameters allow the debugger to easily find and determine 3967 * what the runtime loader is doing and to whom it is doing it. 3968 * 3969 * When the loadhook trap is hit (r_debug_state, set at program 3970 * initialization), the arguments can be found on the stack: 3971 * 3972 * +8 struct link_map *m 3973 * +4 struct r_debug *rd 3974 * +0 RetAddr 3975 */ 3976void 3977r_debug_state(struct r_debug* rd, struct link_map *m) 3978{ 3979 /* 3980 * The following is a hack to force the compiler to emit calls to 3981 * this function, even when optimizing. If the function is empty, 3982 * the compiler is not obliged to emit any code for calls to it, 3983 * even when marked __noinline. However, gdb depends on those 3984 * calls being made. 3985 */ 3986 __compiler_membar(); 3987} 3988 3989/* 3990 * A function called after init routines have completed. This can be used to 3991 * break before a program's entry routine is called, and can be used when 3992 * main is not available in the symbol table. 3993 */ 3994void 3995_r_debug_postinit(struct link_map *m) 3996{ 3997 3998 /* See r_debug_state(). */ 3999 __compiler_membar(); 4000} 4001 4002static void 4003release_object(Obj_Entry *obj) 4004{ 4005 4006 if (obj->holdcount > 0) { 4007 obj->unholdfree = true; 4008 return; 4009 } 4010 munmap(obj->mapbase, obj->mapsize); 4011 linkmap_delete(obj); 4012 obj_free(obj); 4013} 4014 4015/* 4016 * Get address of the pointer variable in the main program. 4017 * Prefer non-weak symbol over the weak one. 4018 */ 4019static const void ** 4020get_program_var_addr(const char *name, RtldLockState *lockstate) 4021{ 4022 SymLook req; 4023 DoneList donelist; 4024 4025 symlook_init(&req, name); 4026 req.lockstate = lockstate; 4027 donelist_init(&donelist); 4028 if (symlook_global(&req, &donelist) != 0) 4029 return (NULL); 4030 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4031 return ((const void **)make_function_pointer(req.sym_out, 4032 req.defobj_out)); 4033 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4034 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4035 else 4036 return ((const void **)(req.defobj_out->relocbase + 4037 req.sym_out->st_value)); 4038} 4039 4040/* 4041 * Set a pointer variable in the main program to the given value. This 4042 * is used to set key variables such as "environ" before any of the 4043 * init functions are called. 4044 */ 4045static void 4046set_program_var(const char *name, const void *value) 4047{ 4048 const void **addr; 4049 4050 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4051 dbg("\"%s\": *%p <-- %p", name, addr, value); 4052 *addr = value; 4053 } 4054} 4055 4056/* 4057 * Search the global objects, including dependencies and main object, 4058 * for the given symbol. 4059 */ 4060static int 4061symlook_global(SymLook *req, DoneList *donelist) 4062{ 4063 SymLook req1; 4064 const Objlist_Entry *elm; 4065 int res; 4066 4067 symlook_init_from_req(&req1, req); 4068 4069 /* Search all objects loaded at program start up. */ 4070 if (req->defobj_out == NULL || 4071 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4072 res = symlook_list(&req1, &list_main, donelist); 4073 if (res == 0 && (req->defobj_out == NULL || 4074 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4075 req->sym_out = req1.sym_out; 4076 req->defobj_out = req1.defobj_out; 4077 assert(req->defobj_out != NULL); 4078 } 4079 } 4080 4081 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4082 STAILQ_FOREACH(elm, &list_global, link) { 4083 if (req->defobj_out != NULL && 4084 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4085 break; 4086 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4087 if (res == 0 && (req->defobj_out == NULL || 4088 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4089 req->sym_out = req1.sym_out; 4090 req->defobj_out = req1.defobj_out; 4091 assert(req->defobj_out != NULL); 4092 } 4093 } 4094 4095 return (req->sym_out != NULL ? 0 : ESRCH); 4096} 4097 4098/* 4099 * Given a symbol name in a referencing object, find the corresponding 4100 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4101 * no definition was found. Returns a pointer to the Obj_Entry of the 4102 * defining object via the reference parameter DEFOBJ_OUT. 4103 */ 4104static int 4105symlook_default(SymLook *req, const Obj_Entry *refobj) 4106{ 4107 DoneList donelist; 4108 const Objlist_Entry *elm; 4109 SymLook req1; 4110 int res; 4111 4112 donelist_init(&donelist); 4113 symlook_init_from_req(&req1, req); 4114 4115 /* 4116 * Look first in the referencing object if linked symbolically, 4117 * and similarly handle protected symbols. 4118 */ 4119 res = symlook_obj(&req1, refobj); 4120 if (res == 0 && (refobj->symbolic || 4121 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4122 req->sym_out = req1.sym_out; 4123 req->defobj_out = req1.defobj_out; 4124 assert(req->defobj_out != NULL); 4125 } 4126 if (refobj->symbolic || req->defobj_out != NULL) 4127 donelist_check(&donelist, refobj); 4128 4129 symlook_global(req, &donelist); 4130 4131 /* Search all dlopened DAGs containing the referencing object. */ 4132 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4133 if (req->sym_out != NULL && 4134 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4135 break; 4136 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4137 if (res == 0 && (req->sym_out == NULL || 4138 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4139 req->sym_out = req1.sym_out; 4140 req->defobj_out = req1.defobj_out; 4141 assert(req->defobj_out != NULL); 4142 } 4143 } 4144 4145 /* 4146 * Search the dynamic linker itself, and possibly resolve the 4147 * symbol from there. This is how the application links to 4148 * dynamic linker services such as dlopen. 4149 */ 4150 if (req->sym_out == NULL || 4151 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4152 res = symlook_obj(&req1, &obj_rtld); 4153 if (res == 0) { 4154 req->sym_out = req1.sym_out; 4155 req->defobj_out = req1.defobj_out; 4156 assert(req->defobj_out != NULL); 4157 } 4158 } 4159 4160 return (req->sym_out != NULL ? 0 : ESRCH); 4161} 4162 4163static int 4164symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4165{ 4166 const Elf_Sym *def; 4167 const Obj_Entry *defobj; 4168 const Objlist_Entry *elm; 4169 SymLook req1; 4170 int res; 4171 4172 def = NULL; 4173 defobj = NULL; 4174 STAILQ_FOREACH(elm, objlist, link) { 4175 if (donelist_check(dlp, elm->obj)) 4176 continue; 4177 symlook_init_from_req(&req1, req); 4178 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4179 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4180 def = req1.sym_out; 4181 defobj = req1.defobj_out; 4182 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4183 break; 4184 } 4185 } 4186 } 4187 if (def != NULL) { 4188 req->sym_out = def; 4189 req->defobj_out = defobj; 4190 return (0); 4191 } 4192 return (ESRCH); 4193} 4194 4195/* 4196 * Search the chain of DAGS cointed to by the given Needed_Entry 4197 * for a symbol of the given name. Each DAG is scanned completely 4198 * before advancing to the next one. Returns a pointer to the symbol, 4199 * or NULL if no definition was found. 4200 */ 4201static int 4202symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4203{ 4204 const Elf_Sym *def; 4205 const Needed_Entry *n; 4206 const Obj_Entry *defobj; 4207 SymLook req1; 4208 int res; 4209 4210 def = NULL; 4211 defobj = NULL; 4212 symlook_init_from_req(&req1, req); 4213 for (n = needed; n != NULL; n = n->next) { 4214 if (n->obj == NULL || 4215 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4216 continue; 4217 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4218 def = req1.sym_out; 4219 defobj = req1.defobj_out; 4220 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4221 break; 4222 } 4223 } 4224 if (def != NULL) { 4225 req->sym_out = def; 4226 req->defobj_out = defobj; 4227 return (0); 4228 } 4229 return (ESRCH); 4230} 4231 4232/* 4233 * Search the symbol table of a single shared object for a symbol of 4234 * the given name and version, if requested. Returns a pointer to the 4235 * symbol, or NULL if no definition was found. If the object is 4236 * filter, return filtered symbol from filtee. 4237 * 4238 * The symbol's hash value is passed in for efficiency reasons; that 4239 * eliminates many recomputations of the hash value. 4240 */ 4241int 4242symlook_obj(SymLook *req, const Obj_Entry *obj) 4243{ 4244 DoneList donelist; 4245 SymLook req1; 4246 int flags, res, mres; 4247 4248 /* 4249 * If there is at least one valid hash at this point, we prefer to 4250 * use the faster GNU version if available. 4251 */ 4252 if (obj->valid_hash_gnu) 4253 mres = symlook_obj1_gnu(req, obj); 4254 else if (obj->valid_hash_sysv) 4255 mres = symlook_obj1_sysv(req, obj); 4256 else 4257 return (EINVAL); 4258 4259 if (mres == 0) { 4260 if (obj->needed_filtees != NULL) { 4261 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4262 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4263 donelist_init(&donelist); 4264 symlook_init_from_req(&req1, req); 4265 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4266 if (res == 0) { 4267 req->sym_out = req1.sym_out; 4268 req->defobj_out = req1.defobj_out; 4269 } 4270 return (res); 4271 } 4272 if (obj->needed_aux_filtees != NULL) { 4273 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4274 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4275 donelist_init(&donelist); 4276 symlook_init_from_req(&req1, req); 4277 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4278 if (res == 0) { 4279 req->sym_out = req1.sym_out; 4280 req->defobj_out = req1.defobj_out; 4281 return (res); 4282 } 4283 } 4284 } 4285 return (mres); 4286} 4287 4288/* Symbol match routine common to both hash functions */ 4289static bool 4290matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4291 const unsigned long symnum) 4292{ 4293 Elf_Versym verndx; 4294 const Elf_Sym *symp; 4295 const char *strp; 4296 4297 symp = obj->symtab + symnum; 4298 strp = obj->strtab + symp->st_name; 4299 4300 switch (ELF_ST_TYPE(symp->st_info)) { 4301 case STT_FUNC: 4302 case STT_NOTYPE: 4303 case STT_OBJECT: 4304 case STT_COMMON: 4305 case STT_GNU_IFUNC: 4306 if (symp->st_value == 0) 4307 return (false); 4308 /* fallthrough */ 4309 case STT_TLS: 4310 if (symp->st_shndx != SHN_UNDEF) 4311 break; 4312#ifndef __mips__ 4313 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4314 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4315 break; 4316 /* fallthrough */ 4317#endif 4318 default: 4319 return (false); 4320 } 4321 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4322 return (false); 4323 4324 if (req->ventry == NULL) { 4325 if (obj->versyms != NULL) { 4326 verndx = VER_NDX(obj->versyms[symnum]); 4327 if (verndx > obj->vernum) { 4328 _rtld_error( 4329 "%s: symbol %s references wrong version %d", 4330 obj->path, obj->strtab + symnum, verndx); 4331 return (false); 4332 } 4333 /* 4334 * If we are not called from dlsym (i.e. this 4335 * is a normal relocation from unversioned 4336 * binary), accept the symbol immediately if 4337 * it happens to have first version after this 4338 * shared object became versioned. Otherwise, 4339 * if symbol is versioned and not hidden, 4340 * remember it. If it is the only symbol with 4341 * this name exported by the shared object, it 4342 * will be returned as a match by the calling 4343 * function. If symbol is global (verndx < 2) 4344 * accept it unconditionally. 4345 */ 4346 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4347 verndx == VER_NDX_GIVEN) { 4348 result->sym_out = symp; 4349 return (true); 4350 } 4351 else if (verndx >= VER_NDX_GIVEN) { 4352 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4353 == 0) { 4354 if (result->vsymp == NULL) 4355 result->vsymp = symp; 4356 result->vcount++; 4357 } 4358 return (false); 4359 } 4360 } 4361 result->sym_out = symp; 4362 return (true); 4363 } 4364 if (obj->versyms == NULL) { 4365 if (object_match_name(obj, req->ventry->name)) { 4366 _rtld_error("%s: object %s should provide version %s " 4367 "for symbol %s", obj_rtld.path, obj->path, 4368 req->ventry->name, obj->strtab + symnum); 4369 return (false); 4370 } 4371 } else { 4372 verndx = VER_NDX(obj->versyms[symnum]); 4373 if (verndx > obj->vernum) { 4374 _rtld_error("%s: symbol %s references wrong version %d", 4375 obj->path, obj->strtab + symnum, verndx); 4376 return (false); 4377 } 4378 if (obj->vertab[verndx].hash != req->ventry->hash || 4379 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4380 /* 4381 * Version does not match. Look if this is a 4382 * global symbol and if it is not hidden. If 4383 * global symbol (verndx < 2) is available, 4384 * use it. Do not return symbol if we are 4385 * called by dlvsym, because dlvsym looks for 4386 * a specific version and default one is not 4387 * what dlvsym wants. 4388 */ 4389 if ((req->flags & SYMLOOK_DLSYM) || 4390 (verndx >= VER_NDX_GIVEN) || 4391 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4392 return (false); 4393 } 4394 } 4395 result->sym_out = symp; 4396 return (true); 4397} 4398 4399/* 4400 * Search for symbol using SysV hash function. 4401 * obj->buckets is known not to be NULL at this point; the test for this was 4402 * performed with the obj->valid_hash_sysv assignment. 4403 */ 4404static int 4405symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4406{ 4407 unsigned long symnum; 4408 Sym_Match_Result matchres; 4409 4410 matchres.sym_out = NULL; 4411 matchres.vsymp = NULL; 4412 matchres.vcount = 0; 4413 4414 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4415 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4416 if (symnum >= obj->nchains) 4417 return (ESRCH); /* Bad object */ 4418 4419 if (matched_symbol(req, obj, &matchres, symnum)) { 4420 req->sym_out = matchres.sym_out; 4421 req->defobj_out = obj; 4422 return (0); 4423 } 4424 } 4425 if (matchres.vcount == 1) { 4426 req->sym_out = matchres.vsymp; 4427 req->defobj_out = obj; 4428 return (0); 4429 } 4430 return (ESRCH); 4431} 4432 4433/* Search for symbol using GNU hash function */ 4434static int 4435symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4436{ 4437 Elf_Addr bloom_word; 4438 const Elf32_Word *hashval; 4439 Elf32_Word bucket; 4440 Sym_Match_Result matchres; 4441 unsigned int h1, h2; 4442 unsigned long symnum; 4443 4444 matchres.sym_out = NULL; 4445 matchres.vsymp = NULL; 4446 matchres.vcount = 0; 4447 4448 /* Pick right bitmask word from Bloom filter array */ 4449 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4450 obj->maskwords_bm_gnu]; 4451 4452 /* Calculate modulus word size of gnu hash and its derivative */ 4453 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4454 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4455 4456 /* Filter out the "definitely not in set" queries */ 4457 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4458 return (ESRCH); 4459 4460 /* Locate hash chain and corresponding value element*/ 4461 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4462 if (bucket == 0) 4463 return (ESRCH); 4464 hashval = &obj->chain_zero_gnu[bucket]; 4465 do { 4466 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4467 symnum = hashval - obj->chain_zero_gnu; 4468 if (matched_symbol(req, obj, &matchres, symnum)) { 4469 req->sym_out = matchres.sym_out; 4470 req->defobj_out = obj; 4471 return (0); 4472 } 4473 } 4474 } while ((*hashval++ & 1) == 0); 4475 if (matchres.vcount == 1) { 4476 req->sym_out = matchres.vsymp; 4477 req->defobj_out = obj; 4478 return (0); 4479 } 4480 return (ESRCH); 4481} 4482 4483static void 4484trace_loaded_objects(Obj_Entry *obj) 4485{ 4486 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4487 int c; 4488 4489 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4490 main_local = ""; 4491 4492 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4493 fmt1 = "\t%o => %p (%x)\n"; 4494 4495 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4496 fmt2 = "\t%o (%x)\n"; 4497 4498 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4499 4500 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4501 Needed_Entry *needed; 4502 char *name, *path; 4503 bool is_lib; 4504 4505 if (obj->marker) 4506 continue; 4507 if (list_containers && obj->needed != NULL) 4508 rtld_printf("%s:\n", obj->path); 4509 for (needed = obj->needed; needed; needed = needed->next) { 4510 if (needed->obj != NULL) { 4511 if (needed->obj->traced && !list_containers) 4512 continue; 4513 needed->obj->traced = true; 4514 path = needed->obj->path; 4515 } else 4516 path = "not found"; 4517 4518 name = (char *)obj->strtab + needed->name; 4519 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4520 4521 fmt = is_lib ? fmt1 : fmt2; 4522 while ((c = *fmt++) != '\0') { 4523 switch (c) { 4524 default: 4525 rtld_putchar(c); 4526 continue; 4527 case '\\': 4528 switch (c = *fmt) { 4529 case '\0': 4530 continue; 4531 case 'n': 4532 rtld_putchar('\n'); 4533 break; 4534 case 't': 4535 rtld_putchar('\t'); 4536 break; 4537 } 4538 break; 4539 case '%': 4540 switch (c = *fmt) { 4541 case '\0': 4542 continue; 4543 case '%': 4544 default: 4545 rtld_putchar(c); 4546 break; 4547 case 'A': 4548 rtld_putstr(main_local); 4549 break; 4550 case 'a': 4551 rtld_putstr(obj_main->path); 4552 break; 4553 case 'o': 4554 rtld_putstr(name); 4555 break; 4556#if 0 4557 case 'm': 4558 rtld_printf("%d", sodp->sod_major); 4559 break; 4560 case 'n': 4561 rtld_printf("%d", sodp->sod_minor); 4562 break; 4563#endif 4564 case 'p': 4565 rtld_putstr(path); 4566 break; 4567 case 'x': 4568 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4569 0); 4570 break; 4571 } 4572 break; 4573 } 4574 ++fmt; 4575 } 4576 } 4577 } 4578} 4579 4580/* 4581 * Unload a dlopened object and its dependencies from memory and from 4582 * our data structures. It is assumed that the DAG rooted in the 4583 * object has already been unreferenced, and that the object has a 4584 * reference count of 0. 4585 */ 4586static void 4587unload_object(Obj_Entry *root, RtldLockState *lockstate) 4588{ 4589 Obj_Entry marker, *obj, *next; 4590 4591 assert(root->refcount == 0); 4592 4593 /* 4594 * Pass over the DAG removing unreferenced objects from 4595 * appropriate lists. 4596 */ 4597 unlink_object(root); 4598 4599 /* Unmap all objects that are no longer referenced. */ 4600 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4601 next = TAILQ_NEXT(obj, next); 4602 if (obj->marker || obj->refcount != 0) 4603 continue; 4604 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4605 obj->mapsize, 0, obj->path); 4606 dbg("unloading \"%s\"", obj->path); 4607 /* 4608 * Unlink the object now to prevent new references from 4609 * being acquired while the bind lock is dropped in 4610 * recursive dlclose() invocations. 4611 */ 4612 TAILQ_REMOVE(&obj_list, obj, next); 4613 obj_count--; 4614 4615 if (obj->filtees_loaded) { 4616 if (next != NULL) { 4617 init_marker(&marker); 4618 TAILQ_INSERT_BEFORE(next, &marker, next); 4619 unload_filtees(obj, lockstate); 4620 next = TAILQ_NEXT(&marker, next); 4621 TAILQ_REMOVE(&obj_list, &marker, next); 4622 } else 4623 unload_filtees(obj, lockstate); 4624 } 4625 release_object(obj); 4626 } 4627} 4628 4629static void 4630unlink_object(Obj_Entry *root) 4631{ 4632 Objlist_Entry *elm; 4633 4634 if (root->refcount == 0) { 4635 /* Remove the object from the RTLD_GLOBAL list. */ 4636 objlist_remove(&list_global, root); 4637 4638 /* Remove the object from all objects' DAG lists. */ 4639 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4640 objlist_remove(&elm->obj->dldags, root); 4641 if (elm->obj != root) 4642 unlink_object(elm->obj); 4643 } 4644 } 4645} 4646 4647static void 4648ref_dag(Obj_Entry *root) 4649{ 4650 Objlist_Entry *elm; 4651 4652 assert(root->dag_inited); 4653 STAILQ_FOREACH(elm, &root->dagmembers, link) 4654 elm->obj->refcount++; 4655} 4656 4657static void 4658unref_dag(Obj_Entry *root) 4659{ 4660 Objlist_Entry *elm; 4661 4662 assert(root->dag_inited); 4663 STAILQ_FOREACH(elm, &root->dagmembers, link) 4664 elm->obj->refcount--; 4665} 4666 4667/* 4668 * Common code for MD __tls_get_addr(). 4669 */ 4670static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4671static void * 4672tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4673{ 4674 Elf_Addr *newdtv, *dtv; 4675 RtldLockState lockstate; 4676 int to_copy; 4677 4678 dtv = *dtvp; 4679 /* Check dtv generation in case new modules have arrived */ 4680 if (dtv[0] != tls_dtv_generation) { 4681 wlock_acquire(rtld_bind_lock, &lockstate); 4682 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4683 to_copy = dtv[1]; 4684 if (to_copy > tls_max_index) 4685 to_copy = tls_max_index; 4686 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4687 newdtv[0] = tls_dtv_generation; 4688 newdtv[1] = tls_max_index; 4689 free(dtv); 4690 lock_release(rtld_bind_lock, &lockstate); 4691 dtv = *dtvp = newdtv; 4692 } 4693 4694 /* Dynamically allocate module TLS if necessary */ 4695 if (dtv[index + 1] == 0) { 4696 /* Signal safe, wlock will block out signals. */ 4697 wlock_acquire(rtld_bind_lock, &lockstate); 4698 if (!dtv[index + 1]) 4699 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4700 lock_release(rtld_bind_lock, &lockstate); 4701 } 4702 return ((void *)(dtv[index + 1] + offset)); 4703} 4704 4705void * 4706tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4707{ 4708 Elf_Addr *dtv; 4709 4710 dtv = *dtvp; 4711 /* Check dtv generation in case new modules have arrived */ 4712 if (__predict_true(dtv[0] == tls_dtv_generation && 4713 dtv[index + 1] != 0)) 4714 return ((void *)(dtv[index + 1] + offset)); 4715 return (tls_get_addr_slow(dtvp, index, offset)); 4716} 4717 4718#if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4719 defined(__powerpc__) || defined(__riscv__) 4720 4721/* 4722 * Allocate Static TLS using the Variant I method. 4723 */ 4724void * 4725allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4726{ 4727 Obj_Entry *obj; 4728 char *tcb; 4729 Elf_Addr **tls; 4730 Elf_Addr *dtv; 4731 Elf_Addr addr; 4732 int i; 4733 4734 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4735 return (oldtcb); 4736 4737 assert(tcbsize >= TLS_TCB_SIZE); 4738 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4739 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4740 4741 if (oldtcb != NULL) { 4742 memcpy(tls, oldtcb, tls_static_space); 4743 free(oldtcb); 4744 4745 /* Adjust the DTV. */ 4746 dtv = tls[0]; 4747 for (i = 0; i < dtv[1]; i++) { 4748 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4749 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4750 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4751 } 4752 } 4753 } else { 4754 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4755 tls[0] = dtv; 4756 dtv[0] = tls_dtv_generation; 4757 dtv[1] = tls_max_index; 4758 4759 for (obj = globallist_curr(objs); obj != NULL; 4760 obj = globallist_next(obj)) { 4761 if (obj->tlsoffset > 0) { 4762 addr = (Elf_Addr)tls + obj->tlsoffset; 4763 if (obj->tlsinitsize > 0) 4764 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4765 if (obj->tlssize > obj->tlsinitsize) 4766 memset((void*) (addr + obj->tlsinitsize), 0, 4767 obj->tlssize - obj->tlsinitsize); 4768 dtv[obj->tlsindex + 1] = addr; 4769 } 4770 } 4771 } 4772 4773 return (tcb); 4774} 4775 4776void 4777free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4778{ 4779 Elf_Addr *dtv; 4780 Elf_Addr tlsstart, tlsend; 4781 int dtvsize, i; 4782 4783 assert(tcbsize >= TLS_TCB_SIZE); 4784 4785 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4786 tlsend = tlsstart + tls_static_space; 4787 4788 dtv = *(Elf_Addr **)tlsstart; 4789 dtvsize = dtv[1]; 4790 for (i = 0; i < dtvsize; i++) { 4791 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4792 free((void*)dtv[i+2]); 4793 } 4794 } 4795 free(dtv); 4796 free(tcb); 4797} 4798 4799#endif 4800 4801#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4802 4803/* 4804 * Allocate Static TLS using the Variant II method. 4805 */ 4806void * 4807allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4808{ 4809 Obj_Entry *obj; 4810 size_t size, ralign; 4811 char *tls; 4812 Elf_Addr *dtv, *olddtv; 4813 Elf_Addr segbase, oldsegbase, addr; 4814 int i; 4815 4816 ralign = tcbalign; 4817 if (tls_static_max_align > ralign) 4818 ralign = tls_static_max_align; 4819 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4820 4821 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4822 tls = malloc_aligned(size, ralign); 4823 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4824 4825 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4826 ((Elf_Addr*)segbase)[0] = segbase; 4827 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4828 4829 dtv[0] = tls_dtv_generation; 4830 dtv[1] = tls_max_index; 4831 4832 if (oldtls) { 4833 /* 4834 * Copy the static TLS block over whole. 4835 */ 4836 oldsegbase = (Elf_Addr) oldtls; 4837 memcpy((void *)(segbase - tls_static_space), 4838 (const void *)(oldsegbase - tls_static_space), 4839 tls_static_space); 4840 4841 /* 4842 * If any dynamic TLS blocks have been created tls_get_addr(), 4843 * move them over. 4844 */ 4845 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4846 for (i = 0; i < olddtv[1]; i++) { 4847 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4848 dtv[i+2] = olddtv[i+2]; 4849 olddtv[i+2] = 0; 4850 } 4851 } 4852 4853 /* 4854 * We assume that this block was the one we created with 4855 * allocate_initial_tls(). 4856 */ 4857 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4858 } else { 4859 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4860 if (obj->marker || obj->tlsoffset == 0) 4861 continue; 4862 addr = segbase - obj->tlsoffset; 4863 memset((void*) (addr + obj->tlsinitsize), 4864 0, obj->tlssize - obj->tlsinitsize); 4865 if (obj->tlsinit) { 4866 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4867 obj->static_tls_copied = true; 4868 } 4869 dtv[obj->tlsindex + 1] = addr; 4870 } 4871 } 4872 4873 return (void*) segbase; 4874} 4875 4876void 4877free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4878{ 4879 Elf_Addr* dtv; 4880 size_t size, ralign; 4881 int dtvsize, i; 4882 Elf_Addr tlsstart, tlsend; 4883 4884 /* 4885 * Figure out the size of the initial TLS block so that we can 4886 * find stuff which ___tls_get_addr() allocated dynamically. 4887 */ 4888 ralign = tcbalign; 4889 if (tls_static_max_align > ralign) 4890 ralign = tls_static_max_align; 4891 size = round(tls_static_space, ralign); 4892 4893 dtv = ((Elf_Addr**)tls)[1]; 4894 dtvsize = dtv[1]; 4895 tlsend = (Elf_Addr) tls; 4896 tlsstart = tlsend - size; 4897 for (i = 0; i < dtvsize; i++) { 4898 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4899 free_aligned((void *)dtv[i + 2]); 4900 } 4901 } 4902 4903 free_aligned((void *)tlsstart); 4904 free((void*) dtv); 4905} 4906 4907#endif 4908 4909/* 4910 * Allocate TLS block for module with given index. 4911 */ 4912void * 4913allocate_module_tls(int index) 4914{ 4915 Obj_Entry* obj; 4916 char* p; 4917 4918 TAILQ_FOREACH(obj, &obj_list, next) { 4919 if (obj->marker) 4920 continue; 4921 if (obj->tlsindex == index) 4922 break; 4923 } 4924 if (!obj) { 4925 _rtld_error("Can't find module with TLS index %d", index); 4926 rtld_die(); 4927 } 4928 4929 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4930 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4931 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4932 4933 return p; 4934} 4935 4936bool 4937allocate_tls_offset(Obj_Entry *obj) 4938{ 4939 size_t off; 4940 4941 if (obj->tls_done) 4942 return true; 4943 4944 if (obj->tlssize == 0) { 4945 obj->tls_done = true; 4946 return true; 4947 } 4948 4949 if (tls_last_offset == 0) 4950 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4951 else 4952 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4953 obj->tlssize, obj->tlsalign); 4954 4955 /* 4956 * If we have already fixed the size of the static TLS block, we 4957 * must stay within that size. When allocating the static TLS, we 4958 * leave a small amount of space spare to be used for dynamically 4959 * loading modules which use static TLS. 4960 */ 4961 if (tls_static_space != 0) { 4962 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4963 return false; 4964 } else if (obj->tlsalign > tls_static_max_align) { 4965 tls_static_max_align = obj->tlsalign; 4966 } 4967 4968 tls_last_offset = obj->tlsoffset = off; 4969 tls_last_size = obj->tlssize; 4970 obj->tls_done = true; 4971 4972 return true; 4973} 4974 4975void 4976free_tls_offset(Obj_Entry *obj) 4977{ 4978 4979 /* 4980 * If we were the last thing to allocate out of the static TLS 4981 * block, we give our space back to the 'allocator'. This is a 4982 * simplistic workaround to allow libGL.so.1 to be loaded and 4983 * unloaded multiple times. 4984 */ 4985 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4986 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4987 tls_last_offset -= obj->tlssize; 4988 tls_last_size = 0; 4989 } 4990} 4991 4992void * 4993_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4994{ 4995 void *ret; 4996 RtldLockState lockstate; 4997 4998 wlock_acquire(rtld_bind_lock, &lockstate); 4999 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5000 tcbsize, tcbalign); 5001 lock_release(rtld_bind_lock, &lockstate); 5002 return (ret); 5003} 5004 5005void 5006_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5007{ 5008 RtldLockState lockstate; 5009 5010 wlock_acquire(rtld_bind_lock, &lockstate); 5011 free_tls(tcb, tcbsize, tcbalign); 5012 lock_release(rtld_bind_lock, &lockstate); 5013} 5014 5015static void 5016object_add_name(Obj_Entry *obj, const char *name) 5017{ 5018 Name_Entry *entry; 5019 size_t len; 5020 5021 len = strlen(name); 5022 entry = malloc(sizeof(Name_Entry) + len); 5023 5024 if (entry != NULL) { 5025 strcpy(entry->name, name); 5026 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5027 } 5028} 5029 5030static int 5031object_match_name(const Obj_Entry *obj, const char *name) 5032{ 5033 Name_Entry *entry; 5034 5035 STAILQ_FOREACH(entry, &obj->names, link) { 5036 if (strcmp(name, entry->name) == 0) 5037 return (1); 5038 } 5039 return (0); 5040} 5041 5042static Obj_Entry * 5043locate_dependency(const Obj_Entry *obj, const char *name) 5044{ 5045 const Objlist_Entry *entry; 5046 const Needed_Entry *needed; 5047 5048 STAILQ_FOREACH(entry, &list_main, link) { 5049 if (object_match_name(entry->obj, name)) 5050 return entry->obj; 5051 } 5052 5053 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5054 if (strcmp(obj->strtab + needed->name, name) == 0 || 5055 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5056 /* 5057 * If there is DT_NEEDED for the name we are looking for, 5058 * we are all set. Note that object might not be found if 5059 * dependency was not loaded yet, so the function can 5060 * return NULL here. This is expected and handled 5061 * properly by the caller. 5062 */ 5063 return (needed->obj); 5064 } 5065 } 5066 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5067 obj->path, name); 5068 rtld_die(); 5069} 5070 5071static int 5072check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5073 const Elf_Vernaux *vna) 5074{ 5075 const Elf_Verdef *vd; 5076 const char *vername; 5077 5078 vername = refobj->strtab + vna->vna_name; 5079 vd = depobj->verdef; 5080 if (vd == NULL) { 5081 _rtld_error("%s: version %s required by %s not defined", 5082 depobj->path, vername, refobj->path); 5083 return (-1); 5084 } 5085 for (;;) { 5086 if (vd->vd_version != VER_DEF_CURRENT) { 5087 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5088 depobj->path, vd->vd_version); 5089 return (-1); 5090 } 5091 if (vna->vna_hash == vd->vd_hash) { 5092 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5093 ((char *)vd + vd->vd_aux); 5094 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5095 return (0); 5096 } 5097 if (vd->vd_next == 0) 5098 break; 5099 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5100 } 5101 if (vna->vna_flags & VER_FLG_WEAK) 5102 return (0); 5103 _rtld_error("%s: version %s required by %s not found", 5104 depobj->path, vername, refobj->path); 5105 return (-1); 5106} 5107 5108static int 5109rtld_verify_object_versions(Obj_Entry *obj) 5110{ 5111 const Elf_Verneed *vn; 5112 const Elf_Verdef *vd; 5113 const Elf_Verdaux *vda; 5114 const Elf_Vernaux *vna; 5115 const Obj_Entry *depobj; 5116 int maxvernum, vernum; 5117 5118 if (obj->ver_checked) 5119 return (0); 5120 obj->ver_checked = true; 5121 5122 maxvernum = 0; 5123 /* 5124 * Walk over defined and required version records and figure out 5125 * max index used by any of them. Do very basic sanity checking 5126 * while there. 5127 */ 5128 vn = obj->verneed; 5129 while (vn != NULL) { 5130 if (vn->vn_version != VER_NEED_CURRENT) { 5131 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5132 obj->path, vn->vn_version); 5133 return (-1); 5134 } 5135 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5136 for (;;) { 5137 vernum = VER_NEED_IDX(vna->vna_other); 5138 if (vernum > maxvernum) 5139 maxvernum = vernum; 5140 if (vna->vna_next == 0) 5141 break; 5142 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5143 } 5144 if (vn->vn_next == 0) 5145 break; 5146 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5147 } 5148 5149 vd = obj->verdef; 5150 while (vd != NULL) { 5151 if (vd->vd_version != VER_DEF_CURRENT) { 5152 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5153 obj->path, vd->vd_version); 5154 return (-1); 5155 } 5156 vernum = VER_DEF_IDX(vd->vd_ndx); 5157 if (vernum > maxvernum) 5158 maxvernum = vernum; 5159 if (vd->vd_next == 0) 5160 break; 5161 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5162 } 5163 5164 if (maxvernum == 0) 5165 return (0); 5166 5167 /* 5168 * Store version information in array indexable by version index. 5169 * Verify that object version requirements are satisfied along the 5170 * way. 5171 */ 5172 obj->vernum = maxvernum + 1; 5173 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5174 5175 vd = obj->verdef; 5176 while (vd != NULL) { 5177 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5178 vernum = VER_DEF_IDX(vd->vd_ndx); 5179 assert(vernum <= maxvernum); 5180 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5181 obj->vertab[vernum].hash = vd->vd_hash; 5182 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5183 obj->vertab[vernum].file = NULL; 5184 obj->vertab[vernum].flags = 0; 5185 } 5186 if (vd->vd_next == 0) 5187 break; 5188 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5189 } 5190 5191 vn = obj->verneed; 5192 while (vn != NULL) { 5193 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5194 if (depobj == NULL) 5195 return (-1); 5196 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5197 for (;;) { 5198 if (check_object_provided_version(obj, depobj, vna)) 5199 return (-1); 5200 vernum = VER_NEED_IDX(vna->vna_other); 5201 assert(vernum <= maxvernum); 5202 obj->vertab[vernum].hash = vna->vna_hash; 5203 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5204 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5205 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5206 VER_INFO_HIDDEN : 0; 5207 if (vna->vna_next == 0) 5208 break; 5209 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5210 } 5211 if (vn->vn_next == 0) 5212 break; 5213 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5214 } 5215 return 0; 5216} 5217 5218static int 5219rtld_verify_versions(const Objlist *objlist) 5220{ 5221 Objlist_Entry *entry; 5222 int rc; 5223 5224 rc = 0; 5225 STAILQ_FOREACH(entry, objlist, link) { 5226 /* 5227 * Skip dummy objects or objects that have their version requirements 5228 * already checked. 5229 */ 5230 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5231 continue; 5232 if (rtld_verify_object_versions(entry->obj) == -1) { 5233 rc = -1; 5234 if (ld_tracing == NULL) 5235 break; 5236 } 5237 } 5238 if (rc == 0 || ld_tracing != NULL) 5239 rc = rtld_verify_object_versions(&obj_rtld); 5240 return rc; 5241} 5242 5243const Ver_Entry * 5244fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5245{ 5246 Elf_Versym vernum; 5247 5248 if (obj->vertab) { 5249 vernum = VER_NDX(obj->versyms[symnum]); 5250 if (vernum >= obj->vernum) { 5251 _rtld_error("%s: symbol %s has wrong verneed value %d", 5252 obj->path, obj->strtab + symnum, vernum); 5253 } else if (obj->vertab[vernum].hash != 0) { 5254 return &obj->vertab[vernum]; 5255 } 5256 } 5257 return NULL; 5258} 5259 5260int 5261_rtld_get_stack_prot(void) 5262{ 5263 5264 return (stack_prot); 5265} 5266 5267int 5268_rtld_is_dlopened(void *arg) 5269{ 5270 Obj_Entry *obj; 5271 RtldLockState lockstate; 5272 int res; 5273 5274 rlock_acquire(rtld_bind_lock, &lockstate); 5275 obj = dlcheck(arg); 5276 if (obj == NULL) 5277 obj = obj_from_addr(arg); 5278 if (obj == NULL) { 5279 _rtld_error("No shared object contains address"); 5280 lock_release(rtld_bind_lock, &lockstate); 5281 return (-1); 5282 } 5283 res = obj->dlopened ? 1 : 0; 5284 lock_release(rtld_bind_lock, &lockstate); 5285 return (res); 5286} 5287 5288static int 5289obj_remap_relro(Obj_Entry *obj, int prot) 5290{ 5291 5292 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5293 prot) == -1) { 5294 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5295 obj->path, prot, rtld_strerror(errno)); 5296 return (-1); 5297 } 5298 return (0); 5299} 5300 5301static int 5302obj_disable_relro(Obj_Entry *obj) 5303{ 5304 5305 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5306} 5307 5308static int 5309obj_enforce_relro(Obj_Entry *obj) 5310{ 5311 5312 return (obj_remap_relro(obj, PROT_READ)); 5313} 5314 5315static void 5316map_stacks_exec(RtldLockState *lockstate) 5317{ 5318 void (*thr_map_stacks_exec)(void); 5319 5320 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5321 return; 5322 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5323 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5324 if (thr_map_stacks_exec != NULL) { 5325 stack_prot |= PROT_EXEC; 5326 thr_map_stacks_exec(); 5327 } 5328} 5329 5330static void 5331distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5332{ 5333 Objlist_Entry *elm; 5334 Obj_Entry *obj; 5335 void (*distrib)(size_t, void *, size_t, size_t); 5336 5337 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5338 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5339 if (distrib == NULL) 5340 return; 5341 STAILQ_FOREACH(elm, list, link) { 5342 obj = elm->obj; 5343 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5344 continue; 5345 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5346 obj->tlssize); 5347 obj->static_tls_copied = true; 5348 } 5349} 5350 5351void 5352symlook_init(SymLook *dst, const char *name) 5353{ 5354 5355 bzero(dst, sizeof(*dst)); 5356 dst->name = name; 5357 dst->hash = elf_hash(name); 5358 dst->hash_gnu = gnu_hash(name); 5359} 5360 5361static void 5362symlook_init_from_req(SymLook *dst, const SymLook *src) 5363{ 5364 5365 dst->name = src->name; 5366 dst->hash = src->hash; 5367 dst->hash_gnu = src->hash_gnu; 5368 dst->ventry = src->ventry; 5369 dst->flags = src->flags; 5370 dst->defobj_out = NULL; 5371 dst->sym_out = NULL; 5372 dst->lockstate = src->lockstate; 5373} 5374 5375static int 5376open_binary_fd(const char *argv0, bool search_in_path) 5377{ 5378 char *pathenv, *pe, binpath[PATH_MAX]; 5379 int fd; 5380 5381 if (search_in_path && strchr(argv0, '/') == NULL) { 5382 pathenv = getenv("PATH"); 5383 if (pathenv == NULL) { 5384 rtld_printf("-p and no PATH environment variable\n"); 5385 rtld_die(); 5386 } 5387 pathenv = strdup(pathenv); 5388 if (pathenv == NULL) { 5389 rtld_printf("Cannot allocate memory\n"); 5390 rtld_die(); 5391 } 5392 fd = -1; 5393 errno = ENOENT; 5394 while ((pe = strsep(&pathenv, ":")) != NULL) { 5395 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5396 sizeof(binpath)) 5397 continue; 5398 if (binpath[0] != '\0' && 5399 strlcat(binpath, "/", sizeof(binpath)) >= 5400 sizeof(binpath)) 5401 continue; 5402 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5403 sizeof(binpath)) 5404 continue; 5405 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5406 if (fd != -1 || errno != ENOENT) 5407 break; 5408 } 5409 free(pathenv); 5410 } else { 5411 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5412 } 5413 5414 if (fd == -1) { 5415 rtld_printf("Opening %s: %s\n", argv0, 5416 rtld_strerror(errno)); 5417 rtld_die(); 5418 } 5419 return (fd); 5420} 5421 5422/* 5423 * Parse a set of command-line arguments. 5424 */ 5425static int 5426parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5427{ 5428 const char *arg; 5429 int fd, i, j, arglen; 5430 char opt; 5431 5432 dbg("Parsing command-line arguments"); 5433 *use_pathp = false; 5434 *fdp = -1; 5435 5436 for (i = 1; i < argc; i++ ) { 5437 arg = argv[i]; 5438 dbg("argv[%d]: '%s'", i, arg); 5439 5440 /* 5441 * rtld arguments end with an explicit "--" or with the first 5442 * non-prefixed argument. 5443 */ 5444 if (strcmp(arg, "--") == 0) { 5445 i++; 5446 break; 5447 } 5448 if (arg[0] != '-') 5449 break; 5450 5451 /* 5452 * All other arguments are single-character options that can 5453 * be combined, so we need to search through `arg` for them. 5454 */ 5455 arglen = strlen(arg); 5456 for (j = 1; j < arglen; j++) { 5457 opt = arg[j]; 5458 if (opt == 'h') { 5459 print_usage(argv[0]); 5460 rtld_die(); 5461 } else if (opt == 'f') { 5462 /* 5463 * -f XX can be used to specify a descriptor for the 5464 * binary named at the command line (i.e., the later 5465 * argument will specify the process name but the 5466 * descriptor is what will actually be executed) 5467 */ 5468 if (j != arglen - 1) { 5469 /* -f must be the last option in, e.g., -abcf */ 5470 _rtld_error("invalid options: %s", arg); 5471 rtld_die(); 5472 } 5473 i++; 5474 fd = parse_integer(argv[i]); 5475 if (fd == -1) { 5476 _rtld_error("invalid file descriptor: '%s'", 5477 argv[i]); 5478 rtld_die(); 5479 } 5480 *fdp = fd; 5481 break; 5482 } else if (opt == 'p') { 5483 *use_pathp = true; 5484 } else { 5485 rtld_printf("invalid argument: '%s'\n", arg); 5486 print_usage(argv[0]); 5487 rtld_die(); 5488 } 5489 } 5490 } 5491 5492 return (i); 5493} 5494 5495/* 5496 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5497 */ 5498static int 5499parse_integer(const char *str) 5500{ 5501 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5502 const char *orig; 5503 int n; 5504 char c; 5505 5506 orig = str; 5507 n = 0; 5508 for (c = *str; c != '\0'; c = *++str) { 5509 if (c < '0' || c > '9') 5510 return (-1); 5511 5512 n *= RADIX; 5513 n += c - '0'; 5514 } 5515 5516 /* Make sure we actually parsed something. */ 5517 if (str == orig) 5518 return (-1); 5519 return (n); 5520} 5521 5522static void 5523print_usage(const char *argv0) 5524{ 5525 5526 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5527 "\n" 5528 "Options:\n" 5529 " -h Display this help message\n" 5530 " -p Search in PATH for named binary\n" 5531 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5532 " -- End of RTLD options\n" 5533 " <binary> Name of process to execute\n" 5534 " <args> Arguments to the executed process\n", argv0); 5535} 5536 5537/* 5538 * Overrides for libc_pic-provided functions. 5539 */ 5540 5541int 5542__getosreldate(void) 5543{ 5544 size_t len; 5545 int oid[2]; 5546 int error, osrel; 5547 5548 if (osreldate != 0) 5549 return (osreldate); 5550 5551 oid[0] = CTL_KERN; 5552 oid[1] = KERN_OSRELDATE; 5553 osrel = 0; 5554 len = sizeof(osrel); 5555 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5556 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5557 osreldate = osrel; 5558 return (osreldate); 5559} 5560 5561void 5562exit(int status) 5563{ 5564 5565 _exit(status); 5566} 5567 5568void (*__cleanup)(void); 5569int __isthreaded = 0; 5570int _thread_autoinit_dummy_decl = 1; 5571 5572/* 5573 * No unresolved symbols for rtld. 5574 */ 5575void 5576__pthread_cxa_finalize(struct dl_phdr_info *a) 5577{ 5578} 5579 5580void 5581__stack_chk_fail(void) 5582{ 5583 5584 _rtld_error("stack overflow detected; terminated"); 5585 rtld_die(); 5586} 5587__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5588 5589void 5590__chk_fail(void) 5591{ 5592 5593 _rtld_error("buffer overflow detected; terminated"); 5594 rtld_die(); 5595} 5596 5597const char * 5598rtld_strerror(int errnum) 5599{ 5600 5601 if (errnum < 0 || errnum >= sys_nerr) 5602 return ("Unknown error"); 5603 return (sys_errlist[errnum]); 5604} 5605 5606/* 5607 * No ifunc relocations. 5608 */ 5609void * 5610memset(void *dest, int c, size_t len) 5611{ 5612 size_t i; 5613 5614 for (i = 0; i < len; i++) 5615 ((char *)dest)[i] = c; 5616 return (dest); 5617} 5618 5619void 5620bzero(void *dest, size_t len) 5621{ 5622 size_t i; 5623 5624 for (i = 0; i < len; i++) 5625 ((char *)dest)[i] = 0; 5626} 5627