rtld.c revision 331205
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 331205 2018-03-19 14:28:20Z marius $"); 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 Obj_Entry *dlcheck(void *); 85static int dlclose_locked(void *, RtldLockState *); 86static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 87 int lo_flags, int mode, RtldLockState *lockstate); 88static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 89static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 90static bool donelist_check(DoneList *, const Obj_Entry *); 91static void errmsg_restore(char *); 92static char *errmsg_save(void); 93static void *fill_search_info(const char *, size_t, void *); 94static char *find_library(const char *, const Obj_Entry *, int *); 95static const char *gethints(bool); 96static void hold_object(Obj_Entry *); 97static void unhold_object(Obj_Entry *); 98static void init_dag(Obj_Entry *); 99static void init_marker(Obj_Entry *); 100static void init_pagesizes(Elf_Auxinfo **aux_info); 101static void init_rtld(caddr_t, Elf_Auxinfo **); 102static void initlist_add_neededs(Needed_Entry *, Objlist *); 103static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 104static void linkmap_add(Obj_Entry *); 105static void linkmap_delete(Obj_Entry *); 106static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107static void unload_filtees(Obj_Entry *, RtldLockState *); 108static int load_needed_objects(Obj_Entry *, int); 109static int load_preload_objects(void); 110static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111static void map_stacks_exec(RtldLockState *); 112static int obj_enforce_relro(Obj_Entry *); 113static Obj_Entry *obj_from_addr(const void *); 114static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 115static void objlist_call_init(Objlist *, RtldLockState *); 116static void objlist_clear(Objlist *); 117static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 118static void objlist_init(Objlist *); 119static void objlist_push_head(Objlist *, Obj_Entry *); 120static void objlist_push_tail(Objlist *, Obj_Entry *); 121static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 122static void objlist_remove(Objlist *, Obj_Entry *); 123static int open_binary_fd(const char *argv0, bool search_in_path); 124static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 125static int parse_integer(const char *); 126static void *path_enumerate(const char *, path_enum_proc, void *); 127static void print_usage(const char *argv0); 128static void release_object(Obj_Entry *); 129static int relocate_object_dag(Obj_Entry *root, bool bind_now, 130 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 131static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 132 int flags, RtldLockState *lockstate); 133static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 134 RtldLockState *); 135static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 136 int flags, RtldLockState *lockstate); 137static int rtld_dirname(const char *, char *); 138static int rtld_dirname_abs(const char *, char *); 139static void *rtld_dlopen(const char *name, int fd, int mode); 140static void rtld_exit(void); 141static char *search_library_path(const char *, const char *); 142static char *search_library_pathfds(const char *, const char *, int *); 143static const void **get_program_var_addr(const char *, RtldLockState *); 144static void set_program_var(const char *, const void *); 145static int symlook_default(SymLook *, const Obj_Entry *refobj); 146static int symlook_global(SymLook *, DoneList *); 147static void symlook_init_from_req(SymLook *, const SymLook *); 148static int symlook_list(SymLook *, const Objlist *, DoneList *); 149static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 150static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 151static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 152static void trace_loaded_objects(Obj_Entry *); 153static void unlink_object(Obj_Entry *); 154static void unload_object(Obj_Entry *, RtldLockState *lockstate); 155static void unref_dag(Obj_Entry *); 156static void ref_dag(Obj_Entry *); 157static char *origin_subst_one(Obj_Entry *, char *, const char *, 158 const char *, bool); 159static char *origin_subst(Obj_Entry *, char *); 160static bool obj_resolve_origin(Obj_Entry *obj); 161static void preinit_main(void); 162static int rtld_verify_versions(const Objlist *); 163static int rtld_verify_object_versions(Obj_Entry *); 164static void object_add_name(Obj_Entry *, const char *); 165static int object_match_name(const Obj_Entry *, const char *); 166static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 167static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 168 struct dl_phdr_info *phdr_info); 169static uint32_t gnu_hash(const char *); 170static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 171 const unsigned long); 172 173void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 174void _r_debug_postinit(struct link_map *) __noinline __exported; 175 176int __sys_openat(int, const char *, int, ...); 177 178/* 179 * Data declarations. 180 */ 181static char *error_message; /* Message for dlerror(), or NULL */ 182struct r_debug r_debug __exported; /* for GDB; */ 183static bool libmap_disable; /* Disable libmap */ 184static bool ld_loadfltr; /* Immediate filters processing */ 185static char *libmap_override; /* Maps to use in addition to libmap.conf */ 186static bool trust; /* False for setuid and setgid programs */ 187static bool dangerous_ld_env; /* True if environment variables have been 188 used to affect the libraries loaded */ 189bool ld_bind_not; /* Disable PLT update */ 190static char *ld_bind_now; /* Environment variable for immediate binding */ 191static char *ld_debug; /* Environment variable for debugging */ 192static char *ld_library_path; /* Environment variable for search path */ 193static char *ld_library_dirs; /* Environment variable for library descriptors */ 194static char *ld_preload; /* Environment variable for libraries to 195 load first */ 196static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 197static char *ld_tracing; /* Called from ldd to print libs */ 198static char *ld_utrace; /* Use utrace() to log events. */ 199static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 200static Obj_Entry *obj_main; /* The main program shared object */ 201static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 202static unsigned int obj_count; /* Number of objects in obj_list */ 203static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 204 205static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 206 STAILQ_HEAD_INITIALIZER(list_global); 207static Objlist list_main = /* Objects loaded at program startup */ 208 STAILQ_HEAD_INITIALIZER(list_main); 209static Objlist list_fini = /* Objects needing fini() calls */ 210 STAILQ_HEAD_INITIALIZER(list_fini); 211 212Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 213 214#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 215 216extern Elf_Dyn _DYNAMIC; 217#pragma weak _DYNAMIC 218 219int dlclose(void *) __exported; 220char *dlerror(void) __exported; 221void *dlopen(const char *, int) __exported; 222void *fdlopen(int, int) __exported; 223void *dlsym(void *, const char *) __exported; 224dlfunc_t dlfunc(void *, const char *) __exported; 225void *dlvsym(void *, const char *, const char *) __exported; 226int dladdr(const void *, Dl_info *) __exported; 227void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 228 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 229int dlinfo(void *, int , void *) __exported; 230int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 231int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 232int _rtld_get_stack_prot(void) __exported; 233int _rtld_is_dlopened(void *) __exported; 234void _rtld_error(const char *, ...) __exported; 235 236int npagesizes, osreldate; 237size_t *pagesizes; 238 239long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 240 241static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 242static int max_stack_flags; 243 244/* 245 * Global declarations normally provided by crt1. The dynamic linker is 246 * not built with crt1, so we have to provide them ourselves. 247 */ 248char *__progname; 249char **environ; 250 251/* 252 * Used to pass argc, argv to init functions. 253 */ 254int main_argc; 255char **main_argv; 256 257/* 258 * Globals to control TLS allocation. 259 */ 260size_t tls_last_offset; /* Static TLS offset of last module */ 261size_t tls_last_size; /* Static TLS size of last module */ 262size_t tls_static_space; /* Static TLS space allocated */ 263size_t tls_static_max_align; 264int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 265int tls_max_index = 1; /* Largest module index allocated */ 266 267bool ld_library_path_rpath = false; 268 269/* 270 * Globals for path names, and such 271 */ 272char *ld_elf_hints_default = _PATH_ELF_HINTS; 273char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 274char *ld_path_rtld = _PATH_RTLD; 275char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 276char *ld_env_prefix = LD_; 277 278/* 279 * Fill in a DoneList with an allocation large enough to hold all of 280 * the currently-loaded objects. Keep this as a macro since it calls 281 * alloca and we want that to occur within the scope of the caller. 282 */ 283#define donelist_init(dlp) \ 284 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 285 assert((dlp)->objs != NULL), \ 286 (dlp)->num_alloc = obj_count, \ 287 (dlp)->num_used = 0) 288 289#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 290 if (ld_utrace != NULL) \ 291 ld_utrace_log(e, h, mb, ms, r, n); \ 292} while (0) 293 294static void 295ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 296 int refcnt, const char *name) 297{ 298 struct utrace_rtld ut; 299 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 300 301 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 302 ut.event = event; 303 ut.handle = handle; 304 ut.mapbase = mapbase; 305 ut.mapsize = mapsize; 306 ut.refcnt = refcnt; 307 bzero(ut.name, sizeof(ut.name)); 308 if (name) 309 strlcpy(ut.name, name, sizeof(ut.name)); 310 utrace(&ut, sizeof(ut)); 311} 312 313#ifdef RTLD_VARIANT_ENV_NAMES 314/* 315 * construct the env variable based on the type of binary that's 316 * running. 317 */ 318static inline const char * 319_LD(const char *var) 320{ 321 static char buffer[128]; 322 323 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 324 strlcat(buffer, var, sizeof(buffer)); 325 return (buffer); 326} 327#else 328#define _LD(x) LD_ x 329#endif 330 331/* 332 * Main entry point for dynamic linking. The first argument is the 333 * stack pointer. The stack is expected to be laid out as described 334 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 335 * Specifically, the stack pointer points to a word containing 336 * ARGC. Following that in the stack is a null-terminated sequence 337 * of pointers to argument strings. Then comes a null-terminated 338 * sequence of pointers to environment strings. Finally, there is a 339 * sequence of "auxiliary vector" entries. 340 * 341 * The second argument points to a place to store the dynamic linker's 342 * exit procedure pointer and the third to a place to store the main 343 * program's object. 344 * 345 * The return value is the main program's entry point. 346 */ 347func_ptr_type 348_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 349{ 350 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 351 Objlist_Entry *entry; 352 Obj_Entry *last_interposer, *obj, *preload_tail; 353 const Elf_Phdr *phdr; 354 Objlist initlist; 355 RtldLockState lockstate; 356 struct stat st; 357 Elf_Addr *argcp; 358 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 359 caddr_t imgentry; 360 char buf[MAXPATHLEN]; 361 int argc, fd, i, mib[2], phnum, rtld_argc; 362 size_t len; 363 bool dir_enable, explicit_fd, search_in_path; 364 365 /* 366 * On entry, the dynamic linker itself has not been relocated yet. 367 * Be very careful not to reference any global data until after 368 * init_rtld has returned. It is OK to reference file-scope statics 369 * and string constants, and to call static and global functions. 370 */ 371 372 /* Find the auxiliary vector on the stack. */ 373 argcp = sp; 374 argc = *sp++; 375 argv = (char **) sp; 376 sp += argc + 1; /* Skip over arguments and NULL terminator */ 377 env = (char **) sp; 378 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 379 ; 380 aux = (Elf_Auxinfo *) sp; 381 382 /* Digest the auxiliary vector. */ 383 for (i = 0; i < AT_COUNT; i++) 384 aux_info[i] = NULL; 385 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 386 if (auxp->a_type < AT_COUNT) 387 aux_info[auxp->a_type] = auxp; 388 } 389 390 /* Initialize and relocate ourselves. */ 391 assert(aux_info[AT_BASE] != NULL); 392 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 393 394 __progname = obj_rtld.path; 395 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 396 environ = env; 397 main_argc = argc; 398 main_argv = argv; 399 400 if (aux_info[AT_CANARY] != NULL && 401 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 402 i = aux_info[AT_CANARYLEN]->a_un.a_val; 403 if (i > sizeof(__stack_chk_guard)) 404 i = sizeof(__stack_chk_guard); 405 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 406 } else { 407 mib[0] = CTL_KERN; 408 mib[1] = KERN_ARND; 409 410 len = sizeof(__stack_chk_guard); 411 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 412 len != sizeof(__stack_chk_guard)) { 413 /* If sysctl was unsuccessful, use the "terminator canary". */ 414 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 415 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 416 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 417 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 418 } 419 } 420 421 trust = !issetugid(); 422 423 md_abi_variant_hook(aux_info); 424 425 fd = -1; 426 if (aux_info[AT_EXECFD] != NULL) { 427 fd = aux_info[AT_EXECFD]->a_un.a_val; 428 } else { 429 assert(aux_info[AT_PHDR] != NULL); 430 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 431 if (phdr == obj_rtld.phdr) { 432 if (!trust) { 433 rtld_printf("Tainted process refusing to run binary %s\n", 434 argv0); 435 rtld_die(); 436 } 437 dbg("opening main program in direct exec mode"); 438 if (argc >= 2) { 439 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 440 argv0 = argv[rtld_argc]; 441 explicit_fd = (fd != -1); 442 if (!explicit_fd) 443 fd = open_binary_fd(argv0, search_in_path); 444 if (fstat(fd, &st) == -1) { 445 _rtld_error("failed to fstat FD %d (%s): %s", fd, 446 explicit_fd ? "user-provided descriptor" : argv0, 447 rtld_strerror(errno)); 448 rtld_die(); 449 } 450 451 /* 452 * Rough emulation of the permission checks done by 453 * execve(2), only Unix DACs are checked, ACLs are 454 * ignored. Preserve the semantic of disabling owner 455 * to execute if owner x bit is cleared, even if 456 * others x bit is enabled. 457 * mmap(2) does not allow to mmap with PROT_EXEC if 458 * binary' file comes from noexec mount. We cannot 459 * set VV_TEXT on the binary. 460 */ 461 dir_enable = false; 462 if (st.st_uid == geteuid()) { 463 if ((st.st_mode & S_IXUSR) != 0) 464 dir_enable = true; 465 } else if (st.st_gid == getegid()) { 466 if ((st.st_mode & S_IXGRP) != 0) 467 dir_enable = true; 468 } else if ((st.st_mode & S_IXOTH) != 0) { 469 dir_enable = true; 470 } 471 if (!dir_enable) { 472 rtld_printf("No execute permission for binary %s\n", 473 argv0); 474 rtld_die(); 475 } 476 477 /* 478 * For direct exec mode, argv[0] is the interpreter 479 * name, we must remove it and shift arguments left 480 * before invoking binary main. Since stack layout 481 * places environment pointers and aux vectors right 482 * after the terminating NULL, we must shift 483 * environment and aux as well. 484 */ 485 main_argc = argc - rtld_argc; 486 for (i = 0; i <= main_argc; i++) 487 argv[i] = argv[i + rtld_argc]; 488 *argcp -= rtld_argc; 489 environ = env = envp = argv + main_argc + 1; 490 do { 491 *envp = *(envp + rtld_argc); 492 envp++; 493 } while (*envp != NULL); 494 aux = auxp = (Elf_Auxinfo *)envp; 495 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 496 for (;; auxp++, auxpf++) { 497 *auxp = *auxpf; 498 if (auxp->a_type == AT_NULL) 499 break; 500 } 501 } else { 502 rtld_printf("no binary\n"); 503 rtld_die(); 504 } 505 } 506 } 507 508 ld_bind_now = getenv(_LD("BIND_NOW")); 509 510 /* 511 * If the process is tainted, then we un-set the dangerous environment 512 * variables. The process will be marked as tainted until setuid(2) 513 * is called. If any child process calls setuid(2) we do not want any 514 * future processes to honor the potentially un-safe variables. 515 */ 516 if (!trust) { 517 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 518 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 519 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 520 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 521 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 522 _rtld_error("environment corrupt; aborting"); 523 rtld_die(); 524 } 525 } 526 ld_debug = getenv(_LD("DEBUG")); 527 if (ld_bind_now == NULL) 528 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 529 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 530 libmap_override = getenv(_LD("LIBMAP")); 531 ld_library_path = getenv(_LD("LIBRARY_PATH")); 532 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 533 ld_preload = getenv(_LD("PRELOAD")); 534 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 535 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 536 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 537 if (library_path_rpath != NULL) { 538 if (library_path_rpath[0] == 'y' || 539 library_path_rpath[0] == 'Y' || 540 library_path_rpath[0] == '1') 541 ld_library_path_rpath = true; 542 else 543 ld_library_path_rpath = false; 544 } 545 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 546 (ld_library_path != NULL) || (ld_preload != NULL) || 547 (ld_elf_hints_path != NULL) || ld_loadfltr; 548 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 549 ld_utrace = getenv(_LD("UTRACE")); 550 551 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 552 ld_elf_hints_path = ld_elf_hints_default; 553 554 if (ld_debug != NULL && *ld_debug != '\0') 555 debug = 1; 556 dbg("%s is initialized, base address = %p", __progname, 557 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 558 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 559 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 560 561 dbg("initializing thread locks"); 562 lockdflt_init(); 563 564 /* 565 * Load the main program, or process its program header if it is 566 * already loaded. 567 */ 568 if (fd != -1) { /* Load the main program. */ 569 dbg("loading main program"); 570 obj_main = map_object(fd, argv0, NULL); 571 close(fd); 572 if (obj_main == NULL) 573 rtld_die(); 574 max_stack_flags = obj_main->stack_flags; 575 } else { /* Main program already loaded. */ 576 dbg("processing main program's program header"); 577 assert(aux_info[AT_PHDR] != NULL); 578 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 579 assert(aux_info[AT_PHNUM] != NULL); 580 phnum = aux_info[AT_PHNUM]->a_un.a_val; 581 assert(aux_info[AT_PHENT] != NULL); 582 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 583 assert(aux_info[AT_ENTRY] != NULL); 584 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 585 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 586 rtld_die(); 587 } 588 589 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 590 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 591 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 592 if (kexecpath[0] == '/') 593 obj_main->path = kexecpath; 594 else if (getcwd(buf, sizeof(buf)) == NULL || 595 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 596 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 597 obj_main->path = xstrdup(argv0); 598 else 599 obj_main->path = xstrdup(buf); 600 } else { 601 dbg("No AT_EXECPATH or direct exec"); 602 obj_main->path = xstrdup(argv0); 603 } 604 dbg("obj_main path %s", obj_main->path); 605 obj_main->mainprog = true; 606 607 if (aux_info[AT_STACKPROT] != NULL && 608 aux_info[AT_STACKPROT]->a_un.a_val != 0) 609 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 610 611#ifndef COMPAT_32BIT 612 /* 613 * Get the actual dynamic linker pathname from the executable if 614 * possible. (It should always be possible.) That ensures that 615 * gdb will find the right dynamic linker even if a non-standard 616 * one is being used. 617 */ 618 if (obj_main->interp != NULL && 619 strcmp(obj_main->interp, obj_rtld.path) != 0) { 620 free(obj_rtld.path); 621 obj_rtld.path = xstrdup(obj_main->interp); 622 __progname = obj_rtld.path; 623 } 624#endif 625 626 digest_dynamic(obj_main, 0); 627 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 628 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 629 obj_main->dynsymcount); 630 631 linkmap_add(obj_main); 632 linkmap_add(&obj_rtld); 633 634 /* Link the main program into the list of objects. */ 635 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 636 obj_count++; 637 obj_loads++; 638 639 /* Initialize a fake symbol for resolving undefined weak references. */ 640 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 641 sym_zero.st_shndx = SHN_UNDEF; 642 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 643 644 if (!libmap_disable) 645 libmap_disable = (bool)lm_init(libmap_override); 646 647 dbg("loading LD_PRELOAD libraries"); 648 if (load_preload_objects() == -1) 649 rtld_die(); 650 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 651 652 dbg("loading needed objects"); 653 if (load_needed_objects(obj_main, 0) == -1) 654 rtld_die(); 655 656 /* Make a list of all objects loaded at startup. */ 657 last_interposer = obj_main; 658 TAILQ_FOREACH(obj, &obj_list, next) { 659 if (obj->marker) 660 continue; 661 if (obj->z_interpose && obj != obj_main) { 662 objlist_put_after(&list_main, last_interposer, obj); 663 last_interposer = obj; 664 } else { 665 objlist_push_tail(&list_main, obj); 666 } 667 obj->refcount++; 668 } 669 670 dbg("checking for required versions"); 671 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 672 rtld_die(); 673 674 if (ld_tracing) { /* We're done */ 675 trace_loaded_objects(obj_main); 676 exit(0); 677 } 678 679 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 680 dump_relocations(obj_main); 681 exit (0); 682 } 683 684 /* 685 * Processing tls relocations requires having the tls offsets 686 * initialized. Prepare offsets before starting initial 687 * relocation processing. 688 */ 689 dbg("initializing initial thread local storage offsets"); 690 STAILQ_FOREACH(entry, &list_main, link) { 691 /* 692 * Allocate all the initial objects out of the static TLS 693 * block even if they didn't ask for it. 694 */ 695 allocate_tls_offset(entry->obj); 696 } 697 698 if (relocate_objects(obj_main, 699 ld_bind_now != NULL && *ld_bind_now != '\0', 700 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 701 rtld_die(); 702 703 dbg("doing copy relocations"); 704 if (do_copy_relocations(obj_main) == -1) 705 rtld_die(); 706 707 dbg("enforcing main obj relro"); 708 if (obj_enforce_relro(obj_main) == -1) 709 rtld_die(); 710 711 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 712 dump_relocations(obj_main); 713 exit (0); 714 } 715 716 /* 717 * Setup TLS for main thread. This must be done after the 718 * relocations are processed, since tls initialization section 719 * might be the subject for relocations. 720 */ 721 dbg("initializing initial thread local storage"); 722 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 723 724 dbg("initializing key program variables"); 725 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 726 set_program_var("environ", env); 727 set_program_var("__elf_aux_vector", aux); 728 729 /* Make a list of init functions to call. */ 730 objlist_init(&initlist); 731 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 732 preload_tail, &initlist); 733 734 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 735 736 map_stacks_exec(NULL); 737 ifunc_init(aux); 738 739 dbg("resolving ifuncs"); 740 if (resolve_objects_ifunc(obj_main, 741 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 742 NULL) == -1) 743 rtld_die(); 744 745 if (!obj_main->crt_no_init) { 746 /* 747 * Make sure we don't call the main program's init and fini 748 * functions for binaries linked with old crt1 which calls 749 * _init itself. 750 */ 751 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 752 obj_main->preinit_array = obj_main->init_array = 753 obj_main->fini_array = (Elf_Addr)NULL; 754 } 755 756 /* 757 * Execute MD initializers required before we call the objects' 758 * init functions. 759 */ 760 pre_init(); 761 762 wlock_acquire(rtld_bind_lock, &lockstate); 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 lock_release(rtld_bind_lock, &lockstate); 776 777 dbg("transferring control to program entry point = %p", obj_main->entry); 778 779 /* Return the exit procedure and the program entry point. */ 780 *exit_proc = rtld_exit; 781 *objp = obj_main; 782 return (func_ptr_type) obj_main->entry; 783} 784 785void * 786rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 787{ 788 void *ptr; 789 Elf_Addr target; 790 791 ptr = (void *)make_function_pointer(def, obj); 792 target = call_ifunc_resolver(ptr); 793 return ((void *)target); 794} 795 796/* 797 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 798 * Changes to this function should be applied there as well. 799 */ 800Elf_Addr 801_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 802{ 803 const Elf_Rel *rel; 804 const Elf_Sym *def; 805 const Obj_Entry *defobj; 806 Elf_Addr *where; 807 Elf_Addr target; 808 RtldLockState lockstate; 809 810 rlock_acquire(rtld_bind_lock, &lockstate); 811 if (sigsetjmp(lockstate.env, 0) != 0) 812 lock_upgrade(rtld_bind_lock, &lockstate); 813 if (obj->pltrel) 814 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 815 else 816 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 817 818 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 819 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 820 NULL, &lockstate); 821 if (def == NULL) 822 rtld_die(); 823 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 824 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 825 else 826 target = (Elf_Addr)(defobj->relocbase + def->st_value); 827 828 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 829 defobj->strtab + def->st_name, basename(obj->path), 830 (void *)target, basename(defobj->path)); 831 832 /* 833 * Write the new contents for the jmpslot. Note that depending on 834 * architecture, the value which we need to return back to the 835 * lazy binding trampoline may or may not be the target 836 * address. The value returned from reloc_jmpslot() is the value 837 * that the trampoline needs. 838 */ 839 target = reloc_jmpslot(where, target, defobj, obj, rel); 840 lock_release(rtld_bind_lock, &lockstate); 841 return target; 842} 843 844/* 845 * Error reporting function. Use it like printf. If formats the message 846 * into a buffer, and sets things up so that the next call to dlerror() 847 * will return the message. 848 */ 849void 850_rtld_error(const char *fmt, ...) 851{ 852 static char buf[512]; 853 va_list ap; 854 855 va_start(ap, fmt); 856 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 857 error_message = buf; 858 va_end(ap); 859} 860 861/* 862 * Return a dynamically-allocated copy of the current error message, if any. 863 */ 864static char * 865errmsg_save(void) 866{ 867 return error_message == NULL ? NULL : xstrdup(error_message); 868} 869 870/* 871 * Restore the current error message from a copy which was previously saved 872 * by errmsg_save(). The copy is freed. 873 */ 874static void 875errmsg_restore(char *saved_msg) 876{ 877 if (saved_msg == NULL) 878 error_message = NULL; 879 else { 880 _rtld_error("%s", saved_msg); 881 free(saved_msg); 882 } 883} 884 885static const char * 886basename(const char *name) 887{ 888 const char *p = strrchr(name, '/'); 889 return p != NULL ? p + 1 : name; 890} 891 892static struct utsname uts; 893 894static char * 895origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 896 const char *subst, bool may_free) 897{ 898 char *p, *p1, *res, *resp; 899 int subst_len, kw_len, subst_count, old_len, new_len; 900 901 kw_len = strlen(kw); 902 903 /* 904 * First, count the number of the keyword occurrences, to 905 * preallocate the final string. 906 */ 907 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 908 p1 = strstr(p, kw); 909 if (p1 == NULL) 910 break; 911 } 912 913 /* 914 * If the keyword is not found, just return. 915 * 916 * Return non-substituted string if resolution failed. We 917 * cannot do anything more reasonable, the failure mode of the 918 * caller is unresolved library anyway. 919 */ 920 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 921 return (may_free ? real : xstrdup(real)); 922 if (obj != NULL) 923 subst = obj->origin_path; 924 925 /* 926 * There is indeed something to substitute. Calculate the 927 * length of the resulting string, and allocate it. 928 */ 929 subst_len = strlen(subst); 930 old_len = strlen(real); 931 new_len = old_len + (subst_len - kw_len) * subst_count; 932 res = xmalloc(new_len + 1); 933 934 /* 935 * Now, execute the substitution loop. 936 */ 937 for (p = real, resp = res, *resp = '\0';;) { 938 p1 = strstr(p, kw); 939 if (p1 != NULL) { 940 /* Copy the prefix before keyword. */ 941 memcpy(resp, p, p1 - p); 942 resp += p1 - p; 943 /* Keyword replacement. */ 944 memcpy(resp, subst, subst_len); 945 resp += subst_len; 946 *resp = '\0'; 947 p = p1 + kw_len; 948 } else 949 break; 950 } 951 952 /* Copy to the end of string and finish. */ 953 strcat(resp, p); 954 if (may_free) 955 free(real); 956 return (res); 957} 958 959static char * 960origin_subst(Obj_Entry *obj, char *real) 961{ 962 char *res1, *res2, *res3, *res4; 963 964 if (obj == NULL || !trust) 965 return (xstrdup(real)); 966 if (uts.sysname[0] == '\0') { 967 if (uname(&uts) != 0) { 968 _rtld_error("utsname failed: %d", errno); 969 return (NULL); 970 } 971 } 972 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 973 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 974 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 975 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 976 return (res4); 977} 978 979void 980rtld_die(void) 981{ 982 const char *msg = dlerror(); 983 984 if (msg == NULL) 985 msg = "Fatal error"; 986 rtld_fdputstr(STDERR_FILENO, msg); 987 rtld_fdputchar(STDERR_FILENO, '\n'); 988 _exit(1); 989} 990 991/* 992 * Process a shared object's DYNAMIC section, and save the important 993 * information in its Obj_Entry structure. 994 */ 995static void 996digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 997 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 998{ 999 const Elf_Dyn *dynp; 1000 Needed_Entry **needed_tail = &obj->needed; 1001 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1002 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1003 const Elf_Hashelt *hashtab; 1004 const Elf32_Word *hashval; 1005 Elf32_Word bkt, nmaskwords; 1006 int bloom_size32; 1007 int plttype = DT_REL; 1008 1009 *dyn_rpath = NULL; 1010 *dyn_soname = NULL; 1011 *dyn_runpath = NULL; 1012 1013 obj->bind_now = false; 1014 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1015 switch (dynp->d_tag) { 1016 1017 case DT_REL: 1018 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1019 break; 1020 1021 case DT_RELSZ: 1022 obj->relsize = dynp->d_un.d_val; 1023 break; 1024 1025 case DT_RELENT: 1026 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1027 break; 1028 1029 case DT_JMPREL: 1030 obj->pltrel = (const Elf_Rel *) 1031 (obj->relocbase + dynp->d_un.d_ptr); 1032 break; 1033 1034 case DT_PLTRELSZ: 1035 obj->pltrelsize = dynp->d_un.d_val; 1036 break; 1037 1038 case DT_RELA: 1039 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1040 break; 1041 1042 case DT_RELASZ: 1043 obj->relasize = dynp->d_un.d_val; 1044 break; 1045 1046 case DT_RELAENT: 1047 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1048 break; 1049 1050 case DT_PLTREL: 1051 plttype = dynp->d_un.d_val; 1052 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1053 break; 1054 1055 case DT_SYMTAB: 1056 obj->symtab = (const Elf_Sym *) 1057 (obj->relocbase + dynp->d_un.d_ptr); 1058 break; 1059 1060 case DT_SYMENT: 1061 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1062 break; 1063 1064 case DT_STRTAB: 1065 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1066 break; 1067 1068 case DT_STRSZ: 1069 obj->strsize = dynp->d_un.d_val; 1070 break; 1071 1072 case DT_VERNEED: 1073 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1074 dynp->d_un.d_val); 1075 break; 1076 1077 case DT_VERNEEDNUM: 1078 obj->verneednum = dynp->d_un.d_val; 1079 break; 1080 1081 case DT_VERDEF: 1082 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1083 dynp->d_un.d_val); 1084 break; 1085 1086 case DT_VERDEFNUM: 1087 obj->verdefnum = dynp->d_un.d_val; 1088 break; 1089 1090 case DT_VERSYM: 1091 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1092 dynp->d_un.d_val); 1093 break; 1094 1095 case DT_HASH: 1096 { 1097 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1098 dynp->d_un.d_ptr); 1099 obj->nbuckets = hashtab[0]; 1100 obj->nchains = hashtab[1]; 1101 obj->buckets = hashtab + 2; 1102 obj->chains = obj->buckets + obj->nbuckets; 1103 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1104 obj->buckets != NULL; 1105 } 1106 break; 1107 1108 case DT_GNU_HASH: 1109 { 1110 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1111 dynp->d_un.d_ptr); 1112 obj->nbuckets_gnu = hashtab[0]; 1113 obj->symndx_gnu = hashtab[1]; 1114 nmaskwords = hashtab[2]; 1115 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1116 obj->maskwords_bm_gnu = nmaskwords - 1; 1117 obj->shift2_gnu = hashtab[3]; 1118 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1119 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1120 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1121 obj->symndx_gnu; 1122 /* Number of bitmask words is required to be power of 2 */ 1123 obj->valid_hash_gnu = powerof2(nmaskwords) && 1124 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1125 } 1126 break; 1127 1128 case DT_NEEDED: 1129 if (!obj->rtld) { 1130 Needed_Entry *nep = NEW(Needed_Entry); 1131 nep->name = dynp->d_un.d_val; 1132 nep->obj = NULL; 1133 nep->next = NULL; 1134 1135 *needed_tail = nep; 1136 needed_tail = &nep->next; 1137 } 1138 break; 1139 1140 case DT_FILTER: 1141 if (!obj->rtld) { 1142 Needed_Entry *nep = NEW(Needed_Entry); 1143 nep->name = dynp->d_un.d_val; 1144 nep->obj = NULL; 1145 nep->next = NULL; 1146 1147 *needed_filtees_tail = nep; 1148 needed_filtees_tail = &nep->next; 1149 } 1150 break; 1151 1152 case DT_AUXILIARY: 1153 if (!obj->rtld) { 1154 Needed_Entry *nep = NEW(Needed_Entry); 1155 nep->name = dynp->d_un.d_val; 1156 nep->obj = NULL; 1157 nep->next = NULL; 1158 1159 *needed_aux_filtees_tail = nep; 1160 needed_aux_filtees_tail = &nep->next; 1161 } 1162 break; 1163 1164 case DT_PLTGOT: 1165 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1166 break; 1167 1168 case DT_TEXTREL: 1169 obj->textrel = true; 1170 break; 1171 1172 case DT_SYMBOLIC: 1173 obj->symbolic = true; 1174 break; 1175 1176 case DT_RPATH: 1177 /* 1178 * We have to wait until later to process this, because we 1179 * might not have gotten the address of the string table yet. 1180 */ 1181 *dyn_rpath = dynp; 1182 break; 1183 1184 case DT_SONAME: 1185 *dyn_soname = dynp; 1186 break; 1187 1188 case DT_RUNPATH: 1189 *dyn_runpath = dynp; 1190 break; 1191 1192 case DT_INIT: 1193 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1194 break; 1195 1196 case DT_PREINIT_ARRAY: 1197 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1198 break; 1199 1200 case DT_PREINIT_ARRAYSZ: 1201 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1202 break; 1203 1204 case DT_INIT_ARRAY: 1205 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1206 break; 1207 1208 case DT_INIT_ARRAYSZ: 1209 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1210 break; 1211 1212 case DT_FINI: 1213 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1214 break; 1215 1216 case DT_FINI_ARRAY: 1217 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1218 break; 1219 1220 case DT_FINI_ARRAYSZ: 1221 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1222 break; 1223 1224 /* 1225 * Don't process DT_DEBUG on MIPS as the dynamic section 1226 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1227 */ 1228 1229#ifndef __mips__ 1230 case DT_DEBUG: 1231 if (!early) 1232 dbg("Filling in DT_DEBUG entry"); 1233 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1234 break; 1235#endif 1236 1237 case DT_FLAGS: 1238 if (dynp->d_un.d_val & DF_ORIGIN) 1239 obj->z_origin = true; 1240 if (dynp->d_un.d_val & DF_SYMBOLIC) 1241 obj->symbolic = true; 1242 if (dynp->d_un.d_val & DF_TEXTREL) 1243 obj->textrel = true; 1244 if (dynp->d_un.d_val & DF_BIND_NOW) 1245 obj->bind_now = true; 1246 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1247 ;*/ 1248 break; 1249#ifdef __mips__ 1250 case DT_MIPS_LOCAL_GOTNO: 1251 obj->local_gotno = dynp->d_un.d_val; 1252 break; 1253 1254 case DT_MIPS_SYMTABNO: 1255 obj->symtabno = dynp->d_un.d_val; 1256 break; 1257 1258 case DT_MIPS_GOTSYM: 1259 obj->gotsym = dynp->d_un.d_val; 1260 break; 1261 1262 case DT_MIPS_RLD_MAP: 1263 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1264 break; 1265#endif 1266 1267#ifdef __powerpc64__ 1268 case DT_PPC64_GLINK: 1269 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1270 break; 1271#endif 1272 1273 case DT_FLAGS_1: 1274 if (dynp->d_un.d_val & DF_1_NOOPEN) 1275 obj->z_noopen = true; 1276 if (dynp->d_un.d_val & DF_1_ORIGIN) 1277 obj->z_origin = true; 1278 if (dynp->d_un.d_val & DF_1_GLOBAL) 1279 obj->z_global = true; 1280 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1281 obj->bind_now = true; 1282 if (dynp->d_un.d_val & DF_1_NODELETE) 1283 obj->z_nodelete = true; 1284 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1285 obj->z_loadfltr = true; 1286 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1287 obj->z_interpose = true; 1288 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1289 obj->z_nodeflib = true; 1290 break; 1291 1292 default: 1293 if (!early) { 1294 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1295 (long)dynp->d_tag); 1296 } 1297 break; 1298 } 1299 } 1300 1301 obj->traced = false; 1302 1303 if (plttype == DT_RELA) { 1304 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1305 obj->pltrel = NULL; 1306 obj->pltrelasize = obj->pltrelsize; 1307 obj->pltrelsize = 0; 1308 } 1309 1310 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1311 if (obj->valid_hash_sysv) 1312 obj->dynsymcount = obj->nchains; 1313 else if (obj->valid_hash_gnu) { 1314 obj->dynsymcount = 0; 1315 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1316 if (obj->buckets_gnu[bkt] == 0) 1317 continue; 1318 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1319 do 1320 obj->dynsymcount++; 1321 while ((*hashval++ & 1u) == 0); 1322 } 1323 obj->dynsymcount += obj->symndx_gnu; 1324 } 1325} 1326 1327static bool 1328obj_resolve_origin(Obj_Entry *obj) 1329{ 1330 1331 if (obj->origin_path != NULL) 1332 return (true); 1333 obj->origin_path = xmalloc(PATH_MAX); 1334 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1335} 1336 1337static void 1338digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1339 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1340{ 1341 1342 if (obj->z_origin && !obj_resolve_origin(obj)) 1343 rtld_die(); 1344 1345 if (dyn_runpath != NULL) { 1346 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1347 obj->runpath = origin_subst(obj, obj->runpath); 1348 } else if (dyn_rpath != NULL) { 1349 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1350 obj->rpath = origin_subst(obj, obj->rpath); 1351 } 1352 if (dyn_soname != NULL) 1353 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1354} 1355 1356static void 1357digest_dynamic(Obj_Entry *obj, int early) 1358{ 1359 const Elf_Dyn *dyn_rpath; 1360 const Elf_Dyn *dyn_soname; 1361 const Elf_Dyn *dyn_runpath; 1362 1363 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1364 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1365} 1366 1367/* 1368 * Process a shared object's program header. This is used only for the 1369 * main program, when the kernel has already loaded the main program 1370 * into memory before calling the dynamic linker. It creates and 1371 * returns an Obj_Entry structure. 1372 */ 1373static Obj_Entry * 1374digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1375{ 1376 Obj_Entry *obj; 1377 const Elf_Phdr *phlimit = phdr + phnum; 1378 const Elf_Phdr *ph; 1379 Elf_Addr note_start, note_end; 1380 int nsegs = 0; 1381 1382 obj = obj_new(); 1383 for (ph = phdr; ph < phlimit; ph++) { 1384 if (ph->p_type != PT_PHDR) 1385 continue; 1386 1387 obj->phdr = phdr; 1388 obj->phsize = ph->p_memsz; 1389 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1390 break; 1391 } 1392 1393 obj->stack_flags = PF_X | PF_R | PF_W; 1394 1395 for (ph = phdr; ph < phlimit; ph++) { 1396 switch (ph->p_type) { 1397 1398 case PT_INTERP: 1399 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1400 break; 1401 1402 case PT_LOAD: 1403 if (nsegs == 0) { /* First load segment */ 1404 obj->vaddrbase = trunc_page(ph->p_vaddr); 1405 obj->mapbase = obj->vaddrbase + obj->relocbase; 1406 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1407 obj->vaddrbase; 1408 } else { /* Last load segment */ 1409 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1410 obj->vaddrbase; 1411 } 1412 nsegs++; 1413 break; 1414 1415 case PT_DYNAMIC: 1416 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1417 break; 1418 1419 case PT_TLS: 1420 obj->tlsindex = 1; 1421 obj->tlssize = ph->p_memsz; 1422 obj->tlsalign = ph->p_align; 1423 obj->tlsinitsize = ph->p_filesz; 1424 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1425 break; 1426 1427 case PT_GNU_STACK: 1428 obj->stack_flags = ph->p_flags; 1429 break; 1430 1431 case PT_GNU_RELRO: 1432 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1433 obj->relro_size = round_page(ph->p_memsz); 1434 break; 1435 1436 case PT_NOTE: 1437 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1438 note_end = note_start + ph->p_filesz; 1439 digest_notes(obj, note_start, note_end); 1440 break; 1441 } 1442 } 1443 if (nsegs < 1) { 1444 _rtld_error("%s: too few PT_LOAD segments", path); 1445 return NULL; 1446 } 1447 1448 obj->entry = entry; 1449 return obj; 1450} 1451 1452void 1453digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1454{ 1455 const Elf_Note *note; 1456 const char *note_name; 1457 uintptr_t p; 1458 1459 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1460 note = (const Elf_Note *)((const char *)(note + 1) + 1461 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1462 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1463 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1464 note->n_descsz != sizeof(int32_t)) 1465 continue; 1466 if (note->n_type != NT_FREEBSD_ABI_TAG && 1467 note->n_type != NT_FREEBSD_NOINIT_TAG) 1468 continue; 1469 note_name = (const char *)(note + 1); 1470 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1471 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1472 continue; 1473 switch (note->n_type) { 1474 case NT_FREEBSD_ABI_TAG: 1475 /* FreeBSD osrel note */ 1476 p = (uintptr_t)(note + 1); 1477 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1478 obj->osrel = *(const int32_t *)(p); 1479 dbg("note osrel %d", obj->osrel); 1480 break; 1481 case NT_FREEBSD_NOINIT_TAG: 1482 /* FreeBSD 'crt does not call init' note */ 1483 obj->crt_no_init = true; 1484 dbg("note crt_no_init"); 1485 break; 1486 } 1487 } 1488} 1489 1490static Obj_Entry * 1491dlcheck(void *handle) 1492{ 1493 Obj_Entry *obj; 1494 1495 TAILQ_FOREACH(obj, &obj_list, next) { 1496 if (obj == (Obj_Entry *) handle) 1497 break; 1498 } 1499 1500 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1501 _rtld_error("Invalid shared object handle %p", handle); 1502 return NULL; 1503 } 1504 return obj; 1505} 1506 1507/* 1508 * If the given object is already in the donelist, return true. Otherwise 1509 * add the object to the list and return false. 1510 */ 1511static bool 1512donelist_check(DoneList *dlp, const Obj_Entry *obj) 1513{ 1514 unsigned int i; 1515 1516 for (i = 0; i < dlp->num_used; i++) 1517 if (dlp->objs[i] == obj) 1518 return true; 1519 /* 1520 * Our donelist allocation should always be sufficient. But if 1521 * our threads locking isn't working properly, more shared objects 1522 * could have been loaded since we allocated the list. That should 1523 * never happen, but we'll handle it properly just in case it does. 1524 */ 1525 if (dlp->num_used < dlp->num_alloc) 1526 dlp->objs[dlp->num_used++] = obj; 1527 return false; 1528} 1529 1530/* 1531 * Hash function for symbol table lookup. Don't even think about changing 1532 * this. It is specified by the System V ABI. 1533 */ 1534unsigned long 1535elf_hash(const char *name) 1536{ 1537 const unsigned char *p = (const unsigned char *) name; 1538 unsigned long h = 0; 1539 unsigned long g; 1540 1541 while (*p != '\0') { 1542 h = (h << 4) + *p++; 1543 if ((g = h & 0xf0000000) != 0) 1544 h ^= g >> 24; 1545 h &= ~g; 1546 } 1547 return h; 1548} 1549 1550/* 1551 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1552 * unsigned in case it's implemented with a wider type. 1553 */ 1554static uint32_t 1555gnu_hash(const char *s) 1556{ 1557 uint32_t h; 1558 unsigned char c; 1559 1560 h = 5381; 1561 for (c = *s; c != '\0'; c = *++s) 1562 h = h * 33 + c; 1563 return (h & 0xffffffff); 1564} 1565 1566 1567/* 1568 * Find the library with the given name, and return its full pathname. 1569 * The returned string is dynamically allocated. Generates an error 1570 * message and returns NULL if the library cannot be found. 1571 * 1572 * If the second argument is non-NULL, then it refers to an already- 1573 * loaded shared object, whose library search path will be searched. 1574 * 1575 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1576 * descriptor (which is close-on-exec) will be passed out via the third 1577 * argument. 1578 * 1579 * The search order is: 1580 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1581 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1582 * LD_LIBRARY_PATH 1583 * DT_RUNPATH in the referencing file 1584 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1585 * from list) 1586 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1587 * 1588 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1589 */ 1590static char * 1591find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1592{ 1593 char *pathname; 1594 char *name; 1595 bool nodeflib, objgiven; 1596 1597 objgiven = refobj != NULL; 1598 1599 if (libmap_disable || !objgiven || 1600 (name = lm_find(refobj->path, xname)) == NULL) 1601 name = (char *)xname; 1602 1603 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1604 if (name[0] != '/' && !trust) { 1605 _rtld_error("Absolute pathname required for shared object \"%s\"", 1606 name); 1607 return (NULL); 1608 } 1609 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1610 __DECONST(char *, name))); 1611 } 1612 1613 dbg(" Searching for \"%s\"", name); 1614 1615 /* 1616 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1617 * back to pre-conforming behaviour if user requested so with 1618 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1619 * nodeflib. 1620 */ 1621 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1622 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1623 (refobj != NULL && 1624 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1625 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1626 (pathname = search_library_path(name, gethints(false))) != NULL || 1627 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1628 return (pathname); 1629 } else { 1630 nodeflib = objgiven ? refobj->z_nodeflib : false; 1631 if ((objgiven && 1632 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1633 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1634 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1635 (pathname = search_library_path(name, ld_library_path)) != NULL || 1636 (objgiven && 1637 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1638 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1639 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1640 (objgiven && !nodeflib && 1641 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1642 return (pathname); 1643 } 1644 1645 if (objgiven && refobj->path != NULL) { 1646 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1647 name, basename(refobj->path)); 1648 } else { 1649 _rtld_error("Shared object \"%s\" not found", name); 1650 } 1651 return NULL; 1652} 1653 1654/* 1655 * Given a symbol number in a referencing object, find the corresponding 1656 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1657 * no definition was found. Returns a pointer to the Obj_Entry of the 1658 * defining object via the reference parameter DEFOBJ_OUT. 1659 */ 1660const Elf_Sym * 1661find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1662 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1663 RtldLockState *lockstate) 1664{ 1665 const Elf_Sym *ref; 1666 const Elf_Sym *def; 1667 const Obj_Entry *defobj; 1668 const Ver_Entry *ve; 1669 SymLook req; 1670 const char *name; 1671 int res; 1672 1673 /* 1674 * If we have already found this symbol, get the information from 1675 * the cache. 1676 */ 1677 if (symnum >= refobj->dynsymcount) 1678 return NULL; /* Bad object */ 1679 if (cache != NULL && cache[symnum].sym != NULL) { 1680 *defobj_out = cache[symnum].obj; 1681 return cache[symnum].sym; 1682 } 1683 1684 ref = refobj->symtab + symnum; 1685 name = refobj->strtab + ref->st_name; 1686 def = NULL; 1687 defobj = NULL; 1688 ve = NULL; 1689 1690 /* 1691 * We don't have to do a full scale lookup if the symbol is local. 1692 * We know it will bind to the instance in this load module; to 1693 * which we already have a pointer (ie ref). By not doing a lookup, 1694 * we not only improve performance, but it also avoids unresolvable 1695 * symbols when local symbols are not in the hash table. This has 1696 * been seen with the ia64 toolchain. 1697 */ 1698 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1699 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1700 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1701 symnum); 1702 } 1703 symlook_init(&req, name); 1704 req.flags = flags; 1705 ve = req.ventry = fetch_ventry(refobj, symnum); 1706 req.lockstate = lockstate; 1707 res = symlook_default(&req, refobj); 1708 if (res == 0) { 1709 def = req.sym_out; 1710 defobj = req.defobj_out; 1711 } 1712 } else { 1713 def = ref; 1714 defobj = refobj; 1715 } 1716 1717 /* 1718 * If we found no definition and the reference is weak, treat the 1719 * symbol as having the value zero. 1720 */ 1721 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1722 def = &sym_zero; 1723 defobj = obj_main; 1724 } 1725 1726 if (def != NULL) { 1727 *defobj_out = defobj; 1728 /* Record the information in the cache to avoid subsequent lookups. */ 1729 if (cache != NULL) { 1730 cache[symnum].sym = def; 1731 cache[symnum].obj = defobj; 1732 } 1733 } else { 1734 if (refobj != &obj_rtld) 1735 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1736 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1737 } 1738 return def; 1739} 1740 1741/* 1742 * Return the search path from the ldconfig hints file, reading it if 1743 * necessary. If nostdlib is true, then the default search paths are 1744 * not added to result. 1745 * 1746 * Returns NULL if there are problems with the hints file, 1747 * or if the search path there is empty. 1748 */ 1749static const char * 1750gethints(bool nostdlib) 1751{ 1752 static char *hints, *filtered_path; 1753 static struct elfhints_hdr hdr; 1754 struct fill_search_info_args sargs, hargs; 1755 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1756 struct dl_serpath *SLPpath, *hintpath; 1757 char *p; 1758 struct stat hint_stat; 1759 unsigned int SLPndx, hintndx, fndx, fcount; 1760 int fd; 1761 size_t flen; 1762 uint32_t dl; 1763 bool skip; 1764 1765 /* First call, read the hints file */ 1766 if (hints == NULL) { 1767 /* Keep from trying again in case the hints file is bad. */ 1768 hints = ""; 1769 1770 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1771 return (NULL); 1772 1773 /* 1774 * Check of hdr.dirlistlen value against type limit 1775 * intends to pacify static analyzers. Further 1776 * paranoia leads to checks that dirlist is fully 1777 * contained in the file range. 1778 */ 1779 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1780 hdr.magic != ELFHINTS_MAGIC || 1781 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1782 fstat(fd, &hint_stat) == -1) { 1783cleanup1: 1784 close(fd); 1785 hdr.dirlistlen = 0; 1786 return (NULL); 1787 } 1788 dl = hdr.strtab; 1789 if (dl + hdr.dirlist < dl) 1790 goto cleanup1; 1791 dl += hdr.dirlist; 1792 if (dl + hdr.dirlistlen < dl) 1793 goto cleanup1; 1794 dl += hdr.dirlistlen; 1795 if (dl > hint_stat.st_size) 1796 goto cleanup1; 1797 p = xmalloc(hdr.dirlistlen + 1); 1798 1799 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1800 read(fd, p, hdr.dirlistlen + 1) != 1801 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1802 free(p); 1803 goto cleanup1; 1804 } 1805 hints = p; 1806 close(fd); 1807 } 1808 1809 /* 1810 * If caller agreed to receive list which includes the default 1811 * paths, we are done. Otherwise, if we still did not 1812 * calculated filtered result, do it now. 1813 */ 1814 if (!nostdlib) 1815 return (hints[0] != '\0' ? hints : NULL); 1816 if (filtered_path != NULL) 1817 goto filt_ret; 1818 1819 /* 1820 * Obtain the list of all configured search paths, and the 1821 * list of the default paths. 1822 * 1823 * First estimate the size of the results. 1824 */ 1825 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1826 smeta.dls_cnt = 0; 1827 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1828 hmeta.dls_cnt = 0; 1829 1830 sargs.request = RTLD_DI_SERINFOSIZE; 1831 sargs.serinfo = &smeta; 1832 hargs.request = RTLD_DI_SERINFOSIZE; 1833 hargs.serinfo = &hmeta; 1834 1835 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1836 path_enumerate(hints, fill_search_info, &hargs); 1837 1838 SLPinfo = xmalloc(smeta.dls_size); 1839 hintinfo = xmalloc(hmeta.dls_size); 1840 1841 /* 1842 * Next fetch both sets of paths. 1843 */ 1844 sargs.request = RTLD_DI_SERINFO; 1845 sargs.serinfo = SLPinfo; 1846 sargs.serpath = &SLPinfo->dls_serpath[0]; 1847 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1848 1849 hargs.request = RTLD_DI_SERINFO; 1850 hargs.serinfo = hintinfo; 1851 hargs.serpath = &hintinfo->dls_serpath[0]; 1852 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1853 1854 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1855 path_enumerate(hints, fill_search_info, &hargs); 1856 1857 /* 1858 * Now calculate the difference between two sets, by excluding 1859 * standard paths from the full set. 1860 */ 1861 fndx = 0; 1862 fcount = 0; 1863 filtered_path = xmalloc(hdr.dirlistlen + 1); 1864 hintpath = &hintinfo->dls_serpath[0]; 1865 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1866 skip = false; 1867 SLPpath = &SLPinfo->dls_serpath[0]; 1868 /* 1869 * Check each standard path against current. 1870 */ 1871 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1872 /* matched, skip the path */ 1873 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1874 skip = true; 1875 break; 1876 } 1877 } 1878 if (skip) 1879 continue; 1880 /* 1881 * Not matched against any standard path, add the path 1882 * to result. Separate consequtive paths with ':'. 1883 */ 1884 if (fcount > 0) { 1885 filtered_path[fndx] = ':'; 1886 fndx++; 1887 } 1888 fcount++; 1889 flen = strlen(hintpath->dls_name); 1890 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1891 fndx += flen; 1892 } 1893 filtered_path[fndx] = '\0'; 1894 1895 free(SLPinfo); 1896 free(hintinfo); 1897 1898filt_ret: 1899 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1900} 1901 1902static void 1903init_dag(Obj_Entry *root) 1904{ 1905 const Needed_Entry *needed; 1906 const Objlist_Entry *elm; 1907 DoneList donelist; 1908 1909 if (root->dag_inited) 1910 return; 1911 donelist_init(&donelist); 1912 1913 /* Root object belongs to own DAG. */ 1914 objlist_push_tail(&root->dldags, root); 1915 objlist_push_tail(&root->dagmembers, root); 1916 donelist_check(&donelist, root); 1917 1918 /* 1919 * Add dependencies of root object to DAG in breadth order 1920 * by exploiting the fact that each new object get added 1921 * to the tail of the dagmembers list. 1922 */ 1923 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1924 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1925 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1926 continue; 1927 objlist_push_tail(&needed->obj->dldags, root); 1928 objlist_push_tail(&root->dagmembers, needed->obj); 1929 } 1930 } 1931 root->dag_inited = true; 1932} 1933 1934static void 1935init_marker(Obj_Entry *marker) 1936{ 1937 1938 bzero(marker, sizeof(*marker)); 1939 marker->marker = true; 1940} 1941 1942Obj_Entry * 1943globallist_curr(const Obj_Entry *obj) 1944{ 1945 1946 for (;;) { 1947 if (obj == NULL) 1948 return (NULL); 1949 if (!obj->marker) 1950 return (__DECONST(Obj_Entry *, obj)); 1951 obj = TAILQ_PREV(obj, obj_entry_q, next); 1952 } 1953} 1954 1955Obj_Entry * 1956globallist_next(const Obj_Entry *obj) 1957{ 1958 1959 for (;;) { 1960 obj = TAILQ_NEXT(obj, next); 1961 if (obj == NULL) 1962 return (NULL); 1963 if (!obj->marker) 1964 return (__DECONST(Obj_Entry *, obj)); 1965 } 1966} 1967 1968/* Prevent the object from being unmapped while the bind lock is dropped. */ 1969static void 1970hold_object(Obj_Entry *obj) 1971{ 1972 1973 obj->holdcount++; 1974} 1975 1976static void 1977unhold_object(Obj_Entry *obj) 1978{ 1979 1980 assert(obj->holdcount > 0); 1981 if (--obj->holdcount == 0 && obj->unholdfree) 1982 release_object(obj); 1983} 1984 1985static void 1986process_z(Obj_Entry *root) 1987{ 1988 const Objlist_Entry *elm; 1989 Obj_Entry *obj; 1990 1991 /* 1992 * Walk over object DAG and process every dependent object 1993 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1994 * to grow their own DAG. 1995 * 1996 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1997 * symlook_global() to work. 1998 * 1999 * For DF_1_NODELETE, the DAG should have its reference upped. 2000 */ 2001 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2002 obj = elm->obj; 2003 if (obj == NULL) 2004 continue; 2005 if (obj->z_nodelete && !obj->ref_nodel) { 2006 dbg("obj %s -z nodelete", obj->path); 2007 init_dag(obj); 2008 ref_dag(obj); 2009 obj->ref_nodel = true; 2010 } 2011 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2012 dbg("obj %s -z global", obj->path); 2013 objlist_push_tail(&list_global, obj); 2014 init_dag(obj); 2015 } 2016 } 2017} 2018/* 2019 * Initialize the dynamic linker. The argument is the address at which 2020 * the dynamic linker has been mapped into memory. The primary task of 2021 * this function is to relocate the dynamic linker. 2022 */ 2023static void 2024init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2025{ 2026 Obj_Entry objtmp; /* Temporary rtld object */ 2027 const Elf_Ehdr *ehdr; 2028 const Elf_Dyn *dyn_rpath; 2029 const Elf_Dyn *dyn_soname; 2030 const Elf_Dyn *dyn_runpath; 2031 2032#ifdef RTLD_INIT_PAGESIZES_EARLY 2033 /* The page size is required by the dynamic memory allocator. */ 2034 init_pagesizes(aux_info); 2035#endif 2036 2037 /* 2038 * Conjure up an Obj_Entry structure for the dynamic linker. 2039 * 2040 * The "path" member can't be initialized yet because string constants 2041 * cannot yet be accessed. Below we will set it correctly. 2042 */ 2043 memset(&objtmp, 0, sizeof(objtmp)); 2044 objtmp.path = NULL; 2045 objtmp.rtld = true; 2046 objtmp.mapbase = mapbase; 2047#ifdef PIC 2048 objtmp.relocbase = mapbase; 2049#endif 2050 2051 objtmp.dynamic = rtld_dynamic(&objtmp); 2052 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2053 assert(objtmp.needed == NULL); 2054#if !defined(__mips__) 2055 /* MIPS has a bogus DT_TEXTREL. */ 2056 assert(!objtmp.textrel); 2057#endif 2058 /* 2059 * Temporarily put the dynamic linker entry into the object list, so 2060 * that symbols can be found. 2061 */ 2062 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2063 2064 ehdr = (Elf_Ehdr *)mapbase; 2065 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2066 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2067 2068 /* Initialize the object list. */ 2069 TAILQ_INIT(&obj_list); 2070 2071 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2072 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2073 2074#ifndef RTLD_INIT_PAGESIZES_EARLY 2075 /* The page size is required by the dynamic memory allocator. */ 2076 init_pagesizes(aux_info); 2077#endif 2078 2079 if (aux_info[AT_OSRELDATE] != NULL) 2080 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2081 2082 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2083 2084 /* Replace the path with a dynamically allocated copy. */ 2085 obj_rtld.path = xstrdup(ld_path_rtld); 2086 2087 r_debug.r_brk = r_debug_state; 2088 r_debug.r_state = RT_CONSISTENT; 2089} 2090 2091/* 2092 * Retrieve the array of supported page sizes. The kernel provides the page 2093 * sizes in increasing order. 2094 */ 2095static void 2096init_pagesizes(Elf_Auxinfo **aux_info) 2097{ 2098 static size_t psa[MAXPAGESIZES]; 2099 int mib[2]; 2100 size_t len, size; 2101 2102 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2103 NULL) { 2104 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2105 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2106 } else { 2107 len = 2; 2108 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2109 size = sizeof(psa); 2110 else { 2111 /* As a fallback, retrieve the base page size. */ 2112 size = sizeof(psa[0]); 2113 if (aux_info[AT_PAGESZ] != NULL) { 2114 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2115 goto psa_filled; 2116 } else { 2117 mib[0] = CTL_HW; 2118 mib[1] = HW_PAGESIZE; 2119 len = 2; 2120 } 2121 } 2122 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2123 _rtld_error("sysctl for hw.pagesize(s) failed"); 2124 rtld_die(); 2125 } 2126psa_filled: 2127 pagesizes = psa; 2128 } 2129 npagesizes = size / sizeof(pagesizes[0]); 2130 /* Discard any invalid entries at the end of the array. */ 2131 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2132 npagesizes--; 2133} 2134 2135/* 2136 * Add the init functions from a needed object list (and its recursive 2137 * needed objects) to "list". This is not used directly; it is a helper 2138 * function for initlist_add_objects(). The write lock must be held 2139 * when this function is called. 2140 */ 2141static void 2142initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2143{ 2144 /* Recursively process the successor needed objects. */ 2145 if (needed->next != NULL) 2146 initlist_add_neededs(needed->next, list); 2147 2148 /* Process the current needed object. */ 2149 if (needed->obj != NULL) 2150 initlist_add_objects(needed->obj, needed->obj, list); 2151} 2152 2153/* 2154 * Scan all of the DAGs rooted in the range of objects from "obj" to 2155 * "tail" and add their init functions to "list". This recurses over 2156 * the DAGs and ensure the proper init ordering such that each object's 2157 * needed libraries are initialized before the object itself. At the 2158 * same time, this function adds the objects to the global finalization 2159 * list "list_fini" in the opposite order. The write lock must be 2160 * held when this function is called. 2161 */ 2162static void 2163initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2164{ 2165 Obj_Entry *nobj; 2166 2167 if (obj->init_scanned || obj->init_done) 2168 return; 2169 obj->init_scanned = true; 2170 2171 /* Recursively process the successor objects. */ 2172 nobj = globallist_next(obj); 2173 if (nobj != NULL && obj != tail) 2174 initlist_add_objects(nobj, tail, list); 2175 2176 /* Recursively process the needed objects. */ 2177 if (obj->needed != NULL) 2178 initlist_add_neededs(obj->needed, list); 2179 if (obj->needed_filtees != NULL) 2180 initlist_add_neededs(obj->needed_filtees, list); 2181 if (obj->needed_aux_filtees != NULL) 2182 initlist_add_neededs(obj->needed_aux_filtees, list); 2183 2184 /* Add the object to the init list. */ 2185 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2186 obj->init_array != (Elf_Addr)NULL) 2187 objlist_push_tail(list, obj); 2188 2189 /* Add the object to the global fini list in the reverse order. */ 2190 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2191 && !obj->on_fini_list) { 2192 objlist_push_head(&list_fini, obj); 2193 obj->on_fini_list = true; 2194 } 2195} 2196 2197#ifndef FPTR_TARGET 2198#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2199#endif 2200 2201static void 2202free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2203{ 2204 Needed_Entry *needed, *needed1; 2205 2206 for (needed = n; needed != NULL; needed = needed->next) { 2207 if (needed->obj != NULL) { 2208 dlclose_locked(needed->obj, lockstate); 2209 needed->obj = NULL; 2210 } 2211 } 2212 for (needed = n; needed != NULL; needed = needed1) { 2213 needed1 = needed->next; 2214 free(needed); 2215 } 2216} 2217 2218static void 2219unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2220{ 2221 2222 free_needed_filtees(obj->needed_filtees, lockstate); 2223 obj->needed_filtees = NULL; 2224 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2225 obj->needed_aux_filtees = NULL; 2226 obj->filtees_loaded = false; 2227} 2228 2229static void 2230load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2231 RtldLockState *lockstate) 2232{ 2233 2234 for (; needed != NULL; needed = needed->next) { 2235 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2236 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2237 RTLD_LOCAL, lockstate); 2238 } 2239} 2240 2241static void 2242load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2243{ 2244 2245 lock_restart_for_upgrade(lockstate); 2246 if (!obj->filtees_loaded) { 2247 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2248 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2249 obj->filtees_loaded = true; 2250 } 2251} 2252 2253static int 2254process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2255{ 2256 Obj_Entry *obj1; 2257 2258 for (; needed != NULL; needed = needed->next) { 2259 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2260 flags & ~RTLD_LO_NOLOAD); 2261 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2262 return (-1); 2263 } 2264 return (0); 2265} 2266 2267/* 2268 * Given a shared object, traverse its list of needed objects, and load 2269 * each of them. Returns 0 on success. Generates an error message and 2270 * returns -1 on failure. 2271 */ 2272static int 2273load_needed_objects(Obj_Entry *first, int flags) 2274{ 2275 Obj_Entry *obj; 2276 2277 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2278 if (obj->marker) 2279 continue; 2280 if (process_needed(obj, obj->needed, flags) == -1) 2281 return (-1); 2282 } 2283 return (0); 2284} 2285 2286static int 2287load_preload_objects(void) 2288{ 2289 char *p = ld_preload; 2290 Obj_Entry *obj; 2291 static const char delim[] = " \t:;"; 2292 2293 if (p == NULL) 2294 return 0; 2295 2296 p += strspn(p, delim); 2297 while (*p != '\0') { 2298 size_t len = strcspn(p, delim); 2299 char savech; 2300 2301 savech = p[len]; 2302 p[len] = '\0'; 2303 obj = load_object(p, -1, NULL, 0); 2304 if (obj == NULL) 2305 return -1; /* XXX - cleanup */ 2306 obj->z_interpose = true; 2307 p[len] = savech; 2308 p += len; 2309 p += strspn(p, delim); 2310 } 2311 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2312 return 0; 2313} 2314 2315static const char * 2316printable_path(const char *path) 2317{ 2318 2319 return (path == NULL ? "<unknown>" : path); 2320} 2321 2322/* 2323 * Load a shared object into memory, if it is not already loaded. The 2324 * object may be specified by name or by user-supplied file descriptor 2325 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2326 * duplicate is. 2327 * 2328 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2329 * on failure. 2330 */ 2331static Obj_Entry * 2332load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2333{ 2334 Obj_Entry *obj; 2335 int fd; 2336 struct stat sb; 2337 char *path; 2338 2339 fd = -1; 2340 if (name != NULL) { 2341 TAILQ_FOREACH(obj, &obj_list, next) { 2342 if (obj->marker || obj->doomed) 2343 continue; 2344 if (object_match_name(obj, name)) 2345 return (obj); 2346 } 2347 2348 path = find_library(name, refobj, &fd); 2349 if (path == NULL) 2350 return (NULL); 2351 } else 2352 path = NULL; 2353 2354 if (fd >= 0) { 2355 /* 2356 * search_library_pathfds() opens a fresh file descriptor for the 2357 * library, so there is no need to dup(). 2358 */ 2359 } else if (fd_u == -1) { 2360 /* 2361 * If we didn't find a match by pathname, or the name is not 2362 * supplied, open the file and check again by device and inode. 2363 * This avoids false mismatches caused by multiple links or ".." 2364 * in pathnames. 2365 * 2366 * To avoid a race, we open the file and use fstat() rather than 2367 * using stat(). 2368 */ 2369 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2370 _rtld_error("Cannot open \"%s\"", path); 2371 free(path); 2372 return (NULL); 2373 } 2374 } else { 2375 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2376 if (fd == -1) { 2377 _rtld_error("Cannot dup fd"); 2378 free(path); 2379 return (NULL); 2380 } 2381 } 2382 if (fstat(fd, &sb) == -1) { 2383 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2384 close(fd); 2385 free(path); 2386 return NULL; 2387 } 2388 TAILQ_FOREACH(obj, &obj_list, next) { 2389 if (obj->marker || obj->doomed) 2390 continue; 2391 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2392 break; 2393 } 2394 if (obj != NULL && name != NULL) { 2395 object_add_name(obj, name); 2396 free(path); 2397 close(fd); 2398 return obj; 2399 } 2400 if (flags & RTLD_LO_NOLOAD) { 2401 free(path); 2402 close(fd); 2403 return (NULL); 2404 } 2405 2406 /* First use of this object, so we must map it in */ 2407 obj = do_load_object(fd, name, path, &sb, flags); 2408 if (obj == NULL) 2409 free(path); 2410 close(fd); 2411 2412 return obj; 2413} 2414 2415static Obj_Entry * 2416do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2417 int flags) 2418{ 2419 Obj_Entry *obj; 2420 struct statfs fs; 2421 2422 /* 2423 * but first, make sure that environment variables haven't been 2424 * used to circumvent the noexec flag on a filesystem. 2425 */ 2426 if (dangerous_ld_env) { 2427 if (fstatfs(fd, &fs) != 0) { 2428 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2429 return NULL; 2430 } 2431 if (fs.f_flags & MNT_NOEXEC) { 2432 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2433 return NULL; 2434 } 2435 } 2436 dbg("loading \"%s\"", printable_path(path)); 2437 obj = map_object(fd, printable_path(path), sbp); 2438 if (obj == NULL) 2439 return NULL; 2440 2441 /* 2442 * If DT_SONAME is present in the object, digest_dynamic2 already 2443 * added it to the object names. 2444 */ 2445 if (name != NULL) 2446 object_add_name(obj, name); 2447 obj->path = path; 2448 digest_dynamic(obj, 0); 2449 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2450 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2451 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2452 RTLD_LO_DLOPEN) { 2453 dbg("refusing to load non-loadable \"%s\"", obj->path); 2454 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2455 munmap(obj->mapbase, obj->mapsize); 2456 obj_free(obj); 2457 return (NULL); 2458 } 2459 2460 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2461 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2462 obj_count++; 2463 obj_loads++; 2464 linkmap_add(obj); /* for GDB & dlinfo() */ 2465 max_stack_flags |= obj->stack_flags; 2466 2467 dbg(" %p .. %p: %s", obj->mapbase, 2468 obj->mapbase + obj->mapsize - 1, obj->path); 2469 if (obj->textrel) 2470 dbg(" WARNING: %s has impure text", obj->path); 2471 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2472 obj->path); 2473 2474 return obj; 2475} 2476 2477static Obj_Entry * 2478obj_from_addr(const void *addr) 2479{ 2480 Obj_Entry *obj; 2481 2482 TAILQ_FOREACH(obj, &obj_list, next) { 2483 if (obj->marker) 2484 continue; 2485 if (addr < (void *) obj->mapbase) 2486 continue; 2487 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2488 return obj; 2489 } 2490 return NULL; 2491} 2492 2493static void 2494preinit_main(void) 2495{ 2496 Elf_Addr *preinit_addr; 2497 int index; 2498 2499 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2500 if (preinit_addr == NULL) 2501 return; 2502 2503 for (index = 0; index < obj_main->preinit_array_num; index++) { 2504 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2505 dbg("calling preinit function for %s at %p", obj_main->path, 2506 (void *)preinit_addr[index]); 2507 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2508 0, 0, obj_main->path); 2509 call_init_pointer(obj_main, preinit_addr[index]); 2510 } 2511 } 2512} 2513 2514/* 2515 * Call the finalization functions for each of the objects in "list" 2516 * belonging to the DAG of "root" and referenced once. If NULL "root" 2517 * is specified, every finalization function will be called regardless 2518 * of the reference count and the list elements won't be freed. All of 2519 * the objects are expected to have non-NULL fini functions. 2520 */ 2521static void 2522objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2523{ 2524 Objlist_Entry *elm; 2525 char *saved_msg; 2526 Elf_Addr *fini_addr; 2527 int index; 2528 2529 assert(root == NULL || root->refcount == 1); 2530 2531 if (root != NULL) 2532 root->doomed = true; 2533 2534 /* 2535 * Preserve the current error message since a fini function might 2536 * call into the dynamic linker and overwrite it. 2537 */ 2538 saved_msg = errmsg_save(); 2539 do { 2540 STAILQ_FOREACH(elm, list, link) { 2541 if (root != NULL && (elm->obj->refcount != 1 || 2542 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2543 continue; 2544 /* Remove object from fini list to prevent recursive invocation. */ 2545 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2546 /* Ensure that new references cannot be acquired. */ 2547 elm->obj->doomed = true; 2548 2549 hold_object(elm->obj); 2550 lock_release(rtld_bind_lock, lockstate); 2551 /* 2552 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2553 * When this happens, DT_FINI_ARRAY is processed first. 2554 */ 2555 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2556 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2557 for (index = elm->obj->fini_array_num - 1; index >= 0; 2558 index--) { 2559 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2560 dbg("calling fini function for %s at %p", 2561 elm->obj->path, (void *)fini_addr[index]); 2562 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2563 (void *)fini_addr[index], 0, 0, elm->obj->path); 2564 call_initfini_pointer(elm->obj, fini_addr[index]); 2565 } 2566 } 2567 } 2568 if (elm->obj->fini != (Elf_Addr)NULL) { 2569 dbg("calling fini function for %s at %p", elm->obj->path, 2570 (void *)elm->obj->fini); 2571 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2572 0, 0, elm->obj->path); 2573 call_initfini_pointer(elm->obj, elm->obj->fini); 2574 } 2575 wlock_acquire(rtld_bind_lock, lockstate); 2576 unhold_object(elm->obj); 2577 /* No need to free anything if process is going down. */ 2578 if (root != NULL) 2579 free(elm); 2580 /* 2581 * We must restart the list traversal after every fini call 2582 * because a dlclose() call from the fini function or from 2583 * another thread might have modified the reference counts. 2584 */ 2585 break; 2586 } 2587 } while (elm != NULL); 2588 errmsg_restore(saved_msg); 2589} 2590 2591/* 2592 * Call the initialization functions for each of the objects in 2593 * "list". All of the objects are expected to have non-NULL init 2594 * functions. 2595 */ 2596static void 2597objlist_call_init(Objlist *list, RtldLockState *lockstate) 2598{ 2599 Objlist_Entry *elm; 2600 Obj_Entry *obj; 2601 char *saved_msg; 2602 Elf_Addr *init_addr; 2603 int index; 2604 2605 /* 2606 * Clean init_scanned flag so that objects can be rechecked and 2607 * possibly initialized earlier if any of vectors called below 2608 * cause the change by using dlopen. 2609 */ 2610 TAILQ_FOREACH(obj, &obj_list, next) { 2611 if (obj->marker) 2612 continue; 2613 obj->init_scanned = false; 2614 } 2615 2616 /* 2617 * Preserve the current error message since an init function might 2618 * call into the dynamic linker and overwrite it. 2619 */ 2620 saved_msg = errmsg_save(); 2621 STAILQ_FOREACH(elm, list, link) { 2622 if (elm->obj->init_done) /* Initialized early. */ 2623 continue; 2624 /* 2625 * Race: other thread might try to use this object before current 2626 * one completes the initialization. Not much can be done here 2627 * without better locking. 2628 */ 2629 elm->obj->init_done = true; 2630 hold_object(elm->obj); 2631 lock_release(rtld_bind_lock, lockstate); 2632 2633 /* 2634 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2635 * When this happens, DT_INIT is processed first. 2636 */ 2637 if (elm->obj->init != (Elf_Addr)NULL) { 2638 dbg("calling init function for %s at %p", elm->obj->path, 2639 (void *)elm->obj->init); 2640 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2641 0, 0, elm->obj->path); 2642 call_initfini_pointer(elm->obj, elm->obj->init); 2643 } 2644 init_addr = (Elf_Addr *)elm->obj->init_array; 2645 if (init_addr != NULL) { 2646 for (index = 0; index < elm->obj->init_array_num; index++) { 2647 if (init_addr[index] != 0 && init_addr[index] != 1) { 2648 dbg("calling init function for %s at %p", elm->obj->path, 2649 (void *)init_addr[index]); 2650 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2651 (void *)init_addr[index], 0, 0, elm->obj->path); 2652 call_init_pointer(elm->obj, init_addr[index]); 2653 } 2654 } 2655 } 2656 wlock_acquire(rtld_bind_lock, lockstate); 2657 unhold_object(elm->obj); 2658 } 2659 errmsg_restore(saved_msg); 2660} 2661 2662static void 2663objlist_clear(Objlist *list) 2664{ 2665 Objlist_Entry *elm; 2666 2667 while (!STAILQ_EMPTY(list)) { 2668 elm = STAILQ_FIRST(list); 2669 STAILQ_REMOVE_HEAD(list, link); 2670 free(elm); 2671 } 2672} 2673 2674static Objlist_Entry * 2675objlist_find(Objlist *list, const Obj_Entry *obj) 2676{ 2677 Objlist_Entry *elm; 2678 2679 STAILQ_FOREACH(elm, list, link) 2680 if (elm->obj == obj) 2681 return elm; 2682 return NULL; 2683} 2684 2685static void 2686objlist_init(Objlist *list) 2687{ 2688 STAILQ_INIT(list); 2689} 2690 2691static void 2692objlist_push_head(Objlist *list, Obj_Entry *obj) 2693{ 2694 Objlist_Entry *elm; 2695 2696 elm = NEW(Objlist_Entry); 2697 elm->obj = obj; 2698 STAILQ_INSERT_HEAD(list, elm, link); 2699} 2700 2701static void 2702objlist_push_tail(Objlist *list, Obj_Entry *obj) 2703{ 2704 Objlist_Entry *elm; 2705 2706 elm = NEW(Objlist_Entry); 2707 elm->obj = obj; 2708 STAILQ_INSERT_TAIL(list, elm, link); 2709} 2710 2711static void 2712objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2713{ 2714 Objlist_Entry *elm, *listelm; 2715 2716 STAILQ_FOREACH(listelm, list, link) { 2717 if (listelm->obj == listobj) 2718 break; 2719 } 2720 elm = NEW(Objlist_Entry); 2721 elm->obj = obj; 2722 if (listelm != NULL) 2723 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2724 else 2725 STAILQ_INSERT_TAIL(list, elm, link); 2726} 2727 2728static void 2729objlist_remove(Objlist *list, Obj_Entry *obj) 2730{ 2731 Objlist_Entry *elm; 2732 2733 if ((elm = objlist_find(list, obj)) != NULL) { 2734 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2735 free(elm); 2736 } 2737} 2738 2739/* 2740 * Relocate dag rooted in the specified object. 2741 * Returns 0 on success, or -1 on failure. 2742 */ 2743 2744static int 2745relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2746 int flags, RtldLockState *lockstate) 2747{ 2748 Objlist_Entry *elm; 2749 int error; 2750 2751 error = 0; 2752 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2753 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2754 lockstate); 2755 if (error == -1) 2756 break; 2757 } 2758 return (error); 2759} 2760 2761/* 2762 * Prepare for, or clean after, relocating an object marked with 2763 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2764 * segments are remapped read-write. After relocations are done, the 2765 * segment's permissions are returned back to the modes specified in 2766 * the phdrs. If any relocation happened, or always for wired 2767 * program, COW is triggered. 2768 */ 2769static int 2770reloc_textrel_prot(Obj_Entry *obj, bool before) 2771{ 2772 const Elf_Phdr *ph; 2773 void *base; 2774 size_t l, sz; 2775 int prot; 2776 2777 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2778 l--, ph++) { 2779 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2780 continue; 2781 base = obj->relocbase + trunc_page(ph->p_vaddr); 2782 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2783 trunc_page(ph->p_vaddr); 2784 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2785 if (mprotect(base, sz, prot) == -1) { 2786 _rtld_error("%s: Cannot write-%sable text segment: %s", 2787 obj->path, before ? "en" : "dis", 2788 rtld_strerror(errno)); 2789 return (-1); 2790 } 2791 } 2792 return (0); 2793} 2794 2795/* 2796 * Relocate single object. 2797 * Returns 0 on success, or -1 on failure. 2798 */ 2799static int 2800relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2801 int flags, RtldLockState *lockstate) 2802{ 2803 2804 if (obj->relocated) 2805 return (0); 2806 obj->relocated = true; 2807 if (obj != rtldobj) 2808 dbg("relocating \"%s\"", obj->path); 2809 2810 if (obj->symtab == NULL || obj->strtab == NULL || 2811 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2812 _rtld_error("%s: Shared object has no run-time symbol table", 2813 obj->path); 2814 return (-1); 2815 } 2816 2817 /* There are relocations to the write-protected text segment. */ 2818 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2819 return (-1); 2820 2821 /* Process the non-PLT non-IFUNC relocations. */ 2822 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2823 return (-1); 2824 2825 /* Re-protected the text segment. */ 2826 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2827 return (-1); 2828 2829 /* Set the special PLT or GOT entries. */ 2830 init_pltgot(obj); 2831 2832 /* Process the PLT relocations. */ 2833 if (reloc_plt(obj) == -1) 2834 return (-1); 2835 /* Relocate the jump slots if we are doing immediate binding. */ 2836 if (obj->bind_now || bind_now) 2837 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2838 return (-1); 2839 2840 /* 2841 * Process the non-PLT IFUNC relocations. The relocations are 2842 * processed in two phases, because IFUNC resolvers may 2843 * reference other symbols, which must be readily processed 2844 * before resolvers are called. 2845 */ 2846 if (obj->non_plt_gnu_ifunc && 2847 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2848 return (-1); 2849 2850 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2851 return (-1); 2852 2853 /* 2854 * Set up the magic number and version in the Obj_Entry. These 2855 * were checked in the crt1.o from the original ElfKit, so we 2856 * set them for backward compatibility. 2857 */ 2858 obj->magic = RTLD_MAGIC; 2859 obj->version = RTLD_VERSION; 2860 2861 return (0); 2862} 2863 2864/* 2865 * Relocate newly-loaded shared objects. The argument is a pointer to 2866 * the Obj_Entry for the first such object. All objects from the first 2867 * to the end of the list of objects are relocated. Returns 0 on success, 2868 * or -1 on failure. 2869 */ 2870static int 2871relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2872 int flags, RtldLockState *lockstate) 2873{ 2874 Obj_Entry *obj; 2875 int error; 2876 2877 for (error = 0, obj = first; obj != NULL; 2878 obj = TAILQ_NEXT(obj, next)) { 2879 if (obj->marker) 2880 continue; 2881 error = relocate_object(obj, bind_now, rtldobj, flags, 2882 lockstate); 2883 if (error == -1) 2884 break; 2885 } 2886 return (error); 2887} 2888 2889/* 2890 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2891 * referencing STT_GNU_IFUNC symbols is postponed till the other 2892 * relocations are done. The indirect functions specified as 2893 * ifunc are allowed to call other symbols, so we need to have 2894 * objects relocated before asking for resolution from indirects. 2895 * 2896 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2897 * instead of the usual lazy handling of PLT slots. It is 2898 * consistent with how GNU does it. 2899 */ 2900static int 2901resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2902 RtldLockState *lockstate) 2903{ 2904 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2905 return (-1); 2906 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2907 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2908 return (-1); 2909 return (0); 2910} 2911 2912static int 2913resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2914 RtldLockState *lockstate) 2915{ 2916 Obj_Entry *obj; 2917 2918 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2919 if (obj->marker) 2920 continue; 2921 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2922 return (-1); 2923 } 2924 return (0); 2925} 2926 2927static int 2928initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2929 RtldLockState *lockstate) 2930{ 2931 Objlist_Entry *elm; 2932 2933 STAILQ_FOREACH(elm, list, link) { 2934 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2935 lockstate) == -1) 2936 return (-1); 2937 } 2938 return (0); 2939} 2940 2941/* 2942 * Cleanup procedure. It will be called (by the atexit mechanism) just 2943 * before the process exits. 2944 */ 2945static void 2946rtld_exit(void) 2947{ 2948 RtldLockState lockstate; 2949 2950 wlock_acquire(rtld_bind_lock, &lockstate); 2951 dbg("rtld_exit()"); 2952 objlist_call_fini(&list_fini, NULL, &lockstate); 2953 /* No need to remove the items from the list, since we are exiting. */ 2954 if (!libmap_disable) 2955 lm_fini(); 2956 lock_release(rtld_bind_lock, &lockstate); 2957} 2958 2959/* 2960 * Iterate over a search path, translate each element, and invoke the 2961 * callback on the result. 2962 */ 2963static void * 2964path_enumerate(const char *path, path_enum_proc callback, void *arg) 2965{ 2966 const char *trans; 2967 if (path == NULL) 2968 return (NULL); 2969 2970 path += strspn(path, ":;"); 2971 while (*path != '\0') { 2972 size_t len; 2973 char *res; 2974 2975 len = strcspn(path, ":;"); 2976 trans = lm_findn(NULL, path, len); 2977 if (trans) 2978 res = callback(trans, strlen(trans), arg); 2979 else 2980 res = callback(path, len, arg); 2981 2982 if (res != NULL) 2983 return (res); 2984 2985 path += len; 2986 path += strspn(path, ":;"); 2987 } 2988 2989 return (NULL); 2990} 2991 2992struct try_library_args { 2993 const char *name; 2994 size_t namelen; 2995 char *buffer; 2996 size_t buflen; 2997}; 2998 2999static void * 3000try_library_path(const char *dir, size_t dirlen, void *param) 3001{ 3002 struct try_library_args *arg; 3003 3004 arg = param; 3005 if (*dir == '/' || trust) { 3006 char *pathname; 3007 3008 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3009 return (NULL); 3010 3011 pathname = arg->buffer; 3012 strncpy(pathname, dir, dirlen); 3013 pathname[dirlen] = '/'; 3014 strcpy(pathname + dirlen + 1, arg->name); 3015 3016 dbg(" Trying \"%s\"", pathname); 3017 if (access(pathname, F_OK) == 0) { /* We found it */ 3018 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3019 strcpy(pathname, arg->buffer); 3020 return (pathname); 3021 } 3022 } 3023 return (NULL); 3024} 3025 3026static char * 3027search_library_path(const char *name, const char *path) 3028{ 3029 char *p; 3030 struct try_library_args arg; 3031 3032 if (path == NULL) 3033 return NULL; 3034 3035 arg.name = name; 3036 arg.namelen = strlen(name); 3037 arg.buffer = xmalloc(PATH_MAX); 3038 arg.buflen = PATH_MAX; 3039 3040 p = path_enumerate(path, try_library_path, &arg); 3041 3042 free(arg.buffer); 3043 3044 return (p); 3045} 3046 3047 3048/* 3049 * Finds the library with the given name using the directory descriptors 3050 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3051 * 3052 * Returns a freshly-opened close-on-exec file descriptor for the library, 3053 * or -1 if the library cannot be found. 3054 */ 3055static char * 3056search_library_pathfds(const char *name, const char *path, int *fdp) 3057{ 3058 char *envcopy, *fdstr, *found, *last_token; 3059 size_t len; 3060 int dirfd, fd; 3061 3062 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3063 3064 /* Don't load from user-specified libdirs into setuid binaries. */ 3065 if (!trust) 3066 return (NULL); 3067 3068 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3069 if (path == NULL) 3070 return (NULL); 3071 3072 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3073 if (name[0] == '/') { 3074 dbg("Absolute path (%s) passed to %s", name, __func__); 3075 return (NULL); 3076 } 3077 3078 /* 3079 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3080 * copy of the path, as strtok_r rewrites separator tokens 3081 * with '\0'. 3082 */ 3083 found = NULL; 3084 envcopy = xstrdup(path); 3085 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3086 fdstr = strtok_r(NULL, ":", &last_token)) { 3087 dirfd = parse_integer(fdstr); 3088 if (dirfd < 0) { 3089 _rtld_error("failed to parse directory FD: '%s'", 3090 fdstr); 3091 break; 3092 } 3093 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3094 if (fd >= 0) { 3095 *fdp = fd; 3096 len = strlen(fdstr) + strlen(name) + 3; 3097 found = xmalloc(len); 3098 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3099 _rtld_error("error generating '%d/%s'", 3100 dirfd, name); 3101 rtld_die(); 3102 } 3103 dbg("open('%s') => %d", found, fd); 3104 break; 3105 } 3106 } 3107 free(envcopy); 3108 3109 return (found); 3110} 3111 3112 3113int 3114dlclose(void *handle) 3115{ 3116 RtldLockState lockstate; 3117 int error; 3118 3119 wlock_acquire(rtld_bind_lock, &lockstate); 3120 error = dlclose_locked(handle, &lockstate); 3121 lock_release(rtld_bind_lock, &lockstate); 3122 return (error); 3123} 3124 3125static int 3126dlclose_locked(void *handle, RtldLockState *lockstate) 3127{ 3128 Obj_Entry *root; 3129 3130 root = dlcheck(handle); 3131 if (root == NULL) 3132 return -1; 3133 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3134 root->path); 3135 3136 /* Unreference the object and its dependencies. */ 3137 root->dl_refcount--; 3138 3139 if (root->refcount == 1) { 3140 /* 3141 * The object will be no longer referenced, so we must unload it. 3142 * First, call the fini functions. 3143 */ 3144 objlist_call_fini(&list_fini, root, lockstate); 3145 3146 unref_dag(root); 3147 3148 /* Finish cleaning up the newly-unreferenced objects. */ 3149 GDB_STATE(RT_DELETE,&root->linkmap); 3150 unload_object(root, lockstate); 3151 GDB_STATE(RT_CONSISTENT,NULL); 3152 } else 3153 unref_dag(root); 3154 3155 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3156 return 0; 3157} 3158 3159char * 3160dlerror(void) 3161{ 3162 char *msg = error_message; 3163 error_message = NULL; 3164 return msg; 3165} 3166 3167/* 3168 * This function is deprecated and has no effect. 3169 */ 3170void 3171dllockinit(void *context, 3172 void *(*lock_create)(void *context), 3173 void (*rlock_acquire)(void *lock), 3174 void (*wlock_acquire)(void *lock), 3175 void (*lock_release)(void *lock), 3176 void (*lock_destroy)(void *lock), 3177 void (*context_destroy)(void *context)) 3178{ 3179 static void *cur_context; 3180 static void (*cur_context_destroy)(void *); 3181 3182 /* Just destroy the context from the previous call, if necessary. */ 3183 if (cur_context_destroy != NULL) 3184 cur_context_destroy(cur_context); 3185 cur_context = context; 3186 cur_context_destroy = context_destroy; 3187} 3188 3189void * 3190dlopen(const char *name, int mode) 3191{ 3192 3193 return (rtld_dlopen(name, -1, mode)); 3194} 3195 3196void * 3197fdlopen(int fd, int mode) 3198{ 3199 3200 return (rtld_dlopen(NULL, fd, mode)); 3201} 3202 3203static void * 3204rtld_dlopen(const char *name, int fd, int mode) 3205{ 3206 RtldLockState lockstate; 3207 int lo_flags; 3208 3209 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3210 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3211 if (ld_tracing != NULL) { 3212 rlock_acquire(rtld_bind_lock, &lockstate); 3213 if (sigsetjmp(lockstate.env, 0) != 0) 3214 lock_upgrade(rtld_bind_lock, &lockstate); 3215 environ = (char **)*get_program_var_addr("environ", &lockstate); 3216 lock_release(rtld_bind_lock, &lockstate); 3217 } 3218 lo_flags = RTLD_LO_DLOPEN; 3219 if (mode & RTLD_NODELETE) 3220 lo_flags |= RTLD_LO_NODELETE; 3221 if (mode & RTLD_NOLOAD) 3222 lo_flags |= RTLD_LO_NOLOAD; 3223 if (ld_tracing != NULL) 3224 lo_flags |= RTLD_LO_TRACE; 3225 3226 return (dlopen_object(name, fd, obj_main, lo_flags, 3227 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3228} 3229 3230static void 3231dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3232{ 3233 3234 obj->dl_refcount--; 3235 unref_dag(obj); 3236 if (obj->refcount == 0) 3237 unload_object(obj, lockstate); 3238} 3239 3240static Obj_Entry * 3241dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3242 int mode, RtldLockState *lockstate) 3243{ 3244 Obj_Entry *old_obj_tail; 3245 Obj_Entry *obj; 3246 Objlist initlist; 3247 RtldLockState mlockstate; 3248 int result; 3249 3250 objlist_init(&initlist); 3251 3252 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3253 wlock_acquire(rtld_bind_lock, &mlockstate); 3254 lockstate = &mlockstate; 3255 } 3256 GDB_STATE(RT_ADD,NULL); 3257 3258 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3259 obj = NULL; 3260 if (name == NULL && fd == -1) { 3261 obj = obj_main; 3262 obj->refcount++; 3263 } else { 3264 obj = load_object(name, fd, refobj, lo_flags); 3265 } 3266 3267 if (obj) { 3268 obj->dl_refcount++; 3269 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3270 objlist_push_tail(&list_global, obj); 3271 if (globallist_next(old_obj_tail) != NULL) { 3272 /* We loaded something new. */ 3273 assert(globallist_next(old_obj_tail) == obj); 3274 result = load_needed_objects(obj, 3275 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3276 init_dag(obj); 3277 ref_dag(obj); 3278 if (result != -1) 3279 result = rtld_verify_versions(&obj->dagmembers); 3280 if (result != -1 && ld_tracing) 3281 goto trace; 3282 if (result == -1 || relocate_object_dag(obj, 3283 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3284 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3285 lockstate) == -1) { 3286 dlopen_cleanup(obj, lockstate); 3287 obj = NULL; 3288 } else if (lo_flags & RTLD_LO_EARLY) { 3289 /* 3290 * Do not call the init functions for early loaded 3291 * filtees. The image is still not initialized enough 3292 * for them to work. 3293 * 3294 * Our object is found by the global object list and 3295 * will be ordered among all init calls done right 3296 * before transferring control to main. 3297 */ 3298 } else { 3299 /* Make list of init functions to call. */ 3300 initlist_add_objects(obj, obj, &initlist); 3301 } 3302 /* 3303 * Process all no_delete or global objects here, given 3304 * them own DAGs to prevent their dependencies from being 3305 * unloaded. This has to be done after we have loaded all 3306 * of the dependencies, so that we do not miss any. 3307 */ 3308 if (obj != NULL) 3309 process_z(obj); 3310 } else { 3311 /* 3312 * Bump the reference counts for objects on this DAG. If 3313 * this is the first dlopen() call for the object that was 3314 * already loaded as a dependency, initialize the dag 3315 * starting at it. 3316 */ 3317 init_dag(obj); 3318 ref_dag(obj); 3319 3320 if ((lo_flags & RTLD_LO_TRACE) != 0) 3321 goto trace; 3322 } 3323 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3324 obj->z_nodelete) && !obj->ref_nodel) { 3325 dbg("obj %s nodelete", obj->path); 3326 ref_dag(obj); 3327 obj->z_nodelete = obj->ref_nodel = true; 3328 } 3329 } 3330 3331 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3332 name); 3333 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3334 3335 if (!(lo_flags & RTLD_LO_EARLY)) { 3336 map_stacks_exec(lockstate); 3337 } 3338 3339 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3340 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3341 lockstate) == -1) { 3342 objlist_clear(&initlist); 3343 dlopen_cleanup(obj, lockstate); 3344 if (lockstate == &mlockstate) 3345 lock_release(rtld_bind_lock, lockstate); 3346 return (NULL); 3347 } 3348 3349 if (!(lo_flags & RTLD_LO_EARLY)) { 3350 /* Call the init functions. */ 3351 objlist_call_init(&initlist, lockstate); 3352 } 3353 objlist_clear(&initlist); 3354 if (lockstate == &mlockstate) 3355 lock_release(rtld_bind_lock, lockstate); 3356 return obj; 3357trace: 3358 trace_loaded_objects(obj); 3359 if (lockstate == &mlockstate) 3360 lock_release(rtld_bind_lock, lockstate); 3361 exit(0); 3362} 3363 3364static void * 3365do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3366 int flags) 3367{ 3368 DoneList donelist; 3369 const Obj_Entry *obj, *defobj; 3370 const Elf_Sym *def; 3371 SymLook req; 3372 RtldLockState lockstate; 3373 tls_index ti; 3374 void *sym; 3375 int res; 3376 3377 def = NULL; 3378 defobj = NULL; 3379 symlook_init(&req, name); 3380 req.ventry = ve; 3381 req.flags = flags | SYMLOOK_IN_PLT; 3382 req.lockstate = &lockstate; 3383 3384 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3385 rlock_acquire(rtld_bind_lock, &lockstate); 3386 if (sigsetjmp(lockstate.env, 0) != 0) 3387 lock_upgrade(rtld_bind_lock, &lockstate); 3388 if (handle == NULL || handle == RTLD_NEXT || 3389 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3390 3391 if ((obj = obj_from_addr(retaddr)) == NULL) { 3392 _rtld_error("Cannot determine caller's shared object"); 3393 lock_release(rtld_bind_lock, &lockstate); 3394 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3395 return NULL; 3396 } 3397 if (handle == NULL) { /* Just the caller's shared object. */ 3398 res = symlook_obj(&req, obj); 3399 if (res == 0) { 3400 def = req.sym_out; 3401 defobj = req.defobj_out; 3402 } 3403 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3404 handle == RTLD_SELF) { /* ... caller included */ 3405 if (handle == RTLD_NEXT) 3406 obj = globallist_next(obj); 3407 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3408 if (obj->marker) 3409 continue; 3410 res = symlook_obj(&req, obj); 3411 if (res == 0) { 3412 if (def == NULL || 3413 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3414 def = req.sym_out; 3415 defobj = req.defobj_out; 3416 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3417 break; 3418 } 3419 } 3420 } 3421 /* 3422 * Search the dynamic linker itself, and possibly resolve the 3423 * symbol from there. This is how the application links to 3424 * dynamic linker services such as dlopen. 3425 */ 3426 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3427 res = symlook_obj(&req, &obj_rtld); 3428 if (res == 0) { 3429 def = req.sym_out; 3430 defobj = req.defobj_out; 3431 } 3432 } 3433 } else { 3434 assert(handle == RTLD_DEFAULT); 3435 res = symlook_default(&req, obj); 3436 if (res == 0) { 3437 defobj = req.defobj_out; 3438 def = req.sym_out; 3439 } 3440 } 3441 } else { 3442 if ((obj = dlcheck(handle)) == NULL) { 3443 lock_release(rtld_bind_lock, &lockstate); 3444 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3445 return NULL; 3446 } 3447 3448 donelist_init(&donelist); 3449 if (obj->mainprog) { 3450 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3451 res = symlook_global(&req, &donelist); 3452 if (res == 0) { 3453 def = req.sym_out; 3454 defobj = req.defobj_out; 3455 } 3456 /* 3457 * Search the dynamic linker itself, and possibly resolve the 3458 * symbol from there. This is how the application links to 3459 * dynamic linker services such as dlopen. 3460 */ 3461 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3462 res = symlook_obj(&req, &obj_rtld); 3463 if (res == 0) { 3464 def = req.sym_out; 3465 defobj = req.defobj_out; 3466 } 3467 } 3468 } 3469 else { 3470 /* Search the whole DAG rooted at the given object. */ 3471 res = symlook_list(&req, &obj->dagmembers, &donelist); 3472 if (res == 0) { 3473 def = req.sym_out; 3474 defobj = req.defobj_out; 3475 } 3476 } 3477 } 3478 3479 if (def != NULL) { 3480 lock_release(rtld_bind_lock, &lockstate); 3481 3482 /* 3483 * The value required by the caller is derived from the value 3484 * of the symbol. this is simply the relocated value of the 3485 * symbol. 3486 */ 3487 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3488 sym = make_function_pointer(def, defobj); 3489 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3490 sym = rtld_resolve_ifunc(defobj, def); 3491 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3492 ti.ti_module = defobj->tlsindex; 3493 ti.ti_offset = def->st_value; 3494 sym = __tls_get_addr(&ti); 3495 } else 3496 sym = defobj->relocbase + def->st_value; 3497 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3498 return (sym); 3499 } 3500 3501 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3502 ve != NULL ? ve->name : ""); 3503 lock_release(rtld_bind_lock, &lockstate); 3504 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3505 return NULL; 3506} 3507 3508void * 3509dlsym(void *handle, const char *name) 3510{ 3511 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3512 SYMLOOK_DLSYM); 3513} 3514 3515dlfunc_t 3516dlfunc(void *handle, const char *name) 3517{ 3518 union { 3519 void *d; 3520 dlfunc_t f; 3521 } rv; 3522 3523 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3524 SYMLOOK_DLSYM); 3525 return (rv.f); 3526} 3527 3528void * 3529dlvsym(void *handle, const char *name, const char *version) 3530{ 3531 Ver_Entry ventry; 3532 3533 ventry.name = version; 3534 ventry.file = NULL; 3535 ventry.hash = elf_hash(version); 3536 ventry.flags= 0; 3537 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3538 SYMLOOK_DLSYM); 3539} 3540 3541int 3542_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3543{ 3544 const Obj_Entry *obj; 3545 RtldLockState lockstate; 3546 3547 rlock_acquire(rtld_bind_lock, &lockstate); 3548 obj = obj_from_addr(addr); 3549 if (obj == NULL) { 3550 _rtld_error("No shared object contains address"); 3551 lock_release(rtld_bind_lock, &lockstate); 3552 return (0); 3553 } 3554 rtld_fill_dl_phdr_info(obj, phdr_info); 3555 lock_release(rtld_bind_lock, &lockstate); 3556 return (1); 3557} 3558 3559int 3560dladdr(const void *addr, Dl_info *info) 3561{ 3562 const Obj_Entry *obj; 3563 const Elf_Sym *def; 3564 void *symbol_addr; 3565 unsigned long symoffset; 3566 RtldLockState lockstate; 3567 3568 rlock_acquire(rtld_bind_lock, &lockstate); 3569 obj = obj_from_addr(addr); 3570 if (obj == NULL) { 3571 _rtld_error("No shared object contains address"); 3572 lock_release(rtld_bind_lock, &lockstate); 3573 return 0; 3574 } 3575 info->dli_fname = obj->path; 3576 info->dli_fbase = obj->mapbase; 3577 info->dli_saddr = (void *)0; 3578 info->dli_sname = NULL; 3579 3580 /* 3581 * Walk the symbol list looking for the symbol whose address is 3582 * closest to the address sent in. 3583 */ 3584 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3585 def = obj->symtab + symoffset; 3586 3587 /* 3588 * For skip the symbol if st_shndx is either SHN_UNDEF or 3589 * SHN_COMMON. 3590 */ 3591 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3592 continue; 3593 3594 /* 3595 * If the symbol is greater than the specified address, or if it 3596 * is further away from addr than the current nearest symbol, 3597 * then reject it. 3598 */ 3599 symbol_addr = obj->relocbase + def->st_value; 3600 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3601 continue; 3602 3603 /* Update our idea of the nearest symbol. */ 3604 info->dli_sname = obj->strtab + def->st_name; 3605 info->dli_saddr = symbol_addr; 3606 3607 /* Exact match? */ 3608 if (info->dli_saddr == addr) 3609 break; 3610 } 3611 lock_release(rtld_bind_lock, &lockstate); 3612 return 1; 3613} 3614 3615int 3616dlinfo(void *handle, int request, void *p) 3617{ 3618 const Obj_Entry *obj; 3619 RtldLockState lockstate; 3620 int error; 3621 3622 rlock_acquire(rtld_bind_lock, &lockstate); 3623 3624 if (handle == NULL || handle == RTLD_SELF) { 3625 void *retaddr; 3626 3627 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3628 if ((obj = obj_from_addr(retaddr)) == NULL) 3629 _rtld_error("Cannot determine caller's shared object"); 3630 } else 3631 obj = dlcheck(handle); 3632 3633 if (obj == NULL) { 3634 lock_release(rtld_bind_lock, &lockstate); 3635 return (-1); 3636 } 3637 3638 error = 0; 3639 switch (request) { 3640 case RTLD_DI_LINKMAP: 3641 *((struct link_map const **)p) = &obj->linkmap; 3642 break; 3643 case RTLD_DI_ORIGIN: 3644 error = rtld_dirname(obj->path, p); 3645 break; 3646 3647 case RTLD_DI_SERINFOSIZE: 3648 case RTLD_DI_SERINFO: 3649 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3650 break; 3651 3652 default: 3653 _rtld_error("Invalid request %d passed to dlinfo()", request); 3654 error = -1; 3655 } 3656 3657 lock_release(rtld_bind_lock, &lockstate); 3658 3659 return (error); 3660} 3661 3662static void 3663rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3664{ 3665 3666 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3667 phdr_info->dlpi_name = obj->path; 3668 phdr_info->dlpi_phdr = obj->phdr; 3669 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3670 phdr_info->dlpi_tls_modid = obj->tlsindex; 3671 phdr_info->dlpi_tls_data = obj->tlsinit; 3672 phdr_info->dlpi_adds = obj_loads; 3673 phdr_info->dlpi_subs = obj_loads - obj_count; 3674} 3675 3676int 3677dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3678{ 3679 struct dl_phdr_info phdr_info; 3680 Obj_Entry *obj, marker; 3681 RtldLockState bind_lockstate, phdr_lockstate; 3682 int error; 3683 3684 init_marker(&marker); 3685 error = 0; 3686 3687 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3688 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3689 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3690 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3691 rtld_fill_dl_phdr_info(obj, &phdr_info); 3692 hold_object(obj); 3693 lock_release(rtld_bind_lock, &bind_lockstate); 3694 3695 error = callback(&phdr_info, sizeof phdr_info, param); 3696 3697 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3698 unhold_object(obj); 3699 obj = globallist_next(&marker); 3700 TAILQ_REMOVE(&obj_list, &marker, next); 3701 if (error != 0) { 3702 lock_release(rtld_bind_lock, &bind_lockstate); 3703 lock_release(rtld_phdr_lock, &phdr_lockstate); 3704 return (error); 3705 } 3706 } 3707 3708 if (error == 0) { 3709 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3710 lock_release(rtld_bind_lock, &bind_lockstate); 3711 error = callback(&phdr_info, sizeof(phdr_info), param); 3712 } 3713 lock_release(rtld_phdr_lock, &phdr_lockstate); 3714 return (error); 3715} 3716 3717static void * 3718fill_search_info(const char *dir, size_t dirlen, void *param) 3719{ 3720 struct fill_search_info_args *arg; 3721 3722 arg = param; 3723 3724 if (arg->request == RTLD_DI_SERINFOSIZE) { 3725 arg->serinfo->dls_cnt ++; 3726 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3727 } else { 3728 struct dl_serpath *s_entry; 3729 3730 s_entry = arg->serpath; 3731 s_entry->dls_name = arg->strspace; 3732 s_entry->dls_flags = arg->flags; 3733 3734 strncpy(arg->strspace, dir, dirlen); 3735 arg->strspace[dirlen] = '\0'; 3736 3737 arg->strspace += dirlen + 1; 3738 arg->serpath++; 3739 } 3740 3741 return (NULL); 3742} 3743 3744static int 3745do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3746{ 3747 struct dl_serinfo _info; 3748 struct fill_search_info_args args; 3749 3750 args.request = RTLD_DI_SERINFOSIZE; 3751 args.serinfo = &_info; 3752 3753 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3754 _info.dls_cnt = 0; 3755 3756 path_enumerate(obj->rpath, fill_search_info, &args); 3757 path_enumerate(ld_library_path, fill_search_info, &args); 3758 path_enumerate(obj->runpath, fill_search_info, &args); 3759 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3760 if (!obj->z_nodeflib) 3761 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3762 3763 3764 if (request == RTLD_DI_SERINFOSIZE) { 3765 info->dls_size = _info.dls_size; 3766 info->dls_cnt = _info.dls_cnt; 3767 return (0); 3768 } 3769 3770 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3771 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3772 return (-1); 3773 } 3774 3775 args.request = RTLD_DI_SERINFO; 3776 args.serinfo = info; 3777 args.serpath = &info->dls_serpath[0]; 3778 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3779 3780 args.flags = LA_SER_RUNPATH; 3781 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3782 return (-1); 3783 3784 args.flags = LA_SER_LIBPATH; 3785 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3786 return (-1); 3787 3788 args.flags = LA_SER_RUNPATH; 3789 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3790 return (-1); 3791 3792 args.flags = LA_SER_CONFIG; 3793 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3794 != NULL) 3795 return (-1); 3796 3797 args.flags = LA_SER_DEFAULT; 3798 if (!obj->z_nodeflib && 3799 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3800 return (-1); 3801 return (0); 3802} 3803 3804static int 3805rtld_dirname(const char *path, char *bname) 3806{ 3807 const char *endp; 3808 3809 /* Empty or NULL string gets treated as "." */ 3810 if (path == NULL || *path == '\0') { 3811 bname[0] = '.'; 3812 bname[1] = '\0'; 3813 return (0); 3814 } 3815 3816 /* Strip trailing slashes */ 3817 endp = path + strlen(path) - 1; 3818 while (endp > path && *endp == '/') 3819 endp--; 3820 3821 /* Find the start of the dir */ 3822 while (endp > path && *endp != '/') 3823 endp--; 3824 3825 /* Either the dir is "/" or there are no slashes */ 3826 if (endp == path) { 3827 bname[0] = *endp == '/' ? '/' : '.'; 3828 bname[1] = '\0'; 3829 return (0); 3830 } else { 3831 do { 3832 endp--; 3833 } while (endp > path && *endp == '/'); 3834 } 3835 3836 if (endp - path + 2 > PATH_MAX) 3837 { 3838 _rtld_error("Filename is too long: %s", path); 3839 return(-1); 3840 } 3841 3842 strncpy(bname, path, endp - path + 1); 3843 bname[endp - path + 1] = '\0'; 3844 return (0); 3845} 3846 3847static int 3848rtld_dirname_abs(const char *path, char *base) 3849{ 3850 char *last; 3851 3852 if (realpath(path, base) == NULL) 3853 return (-1); 3854 dbg("%s -> %s", path, base); 3855 last = strrchr(base, '/'); 3856 if (last == NULL) 3857 return (-1); 3858 if (last != base) 3859 *last = '\0'; 3860 return (0); 3861} 3862 3863static void 3864linkmap_add(Obj_Entry *obj) 3865{ 3866 struct link_map *l = &obj->linkmap; 3867 struct link_map *prev; 3868 3869 obj->linkmap.l_name = obj->path; 3870 obj->linkmap.l_addr = obj->mapbase; 3871 obj->linkmap.l_ld = obj->dynamic; 3872#ifdef __mips__ 3873 /* GDB needs load offset on MIPS to use the symbols */ 3874 obj->linkmap.l_offs = obj->relocbase; 3875#endif 3876 3877 if (r_debug.r_map == NULL) { 3878 r_debug.r_map = l; 3879 return; 3880 } 3881 3882 /* 3883 * Scan to the end of the list, but not past the entry for the 3884 * dynamic linker, which we want to keep at the very end. 3885 */ 3886 for (prev = r_debug.r_map; 3887 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3888 prev = prev->l_next) 3889 ; 3890 3891 /* Link in the new entry. */ 3892 l->l_prev = prev; 3893 l->l_next = prev->l_next; 3894 if (l->l_next != NULL) 3895 l->l_next->l_prev = l; 3896 prev->l_next = l; 3897} 3898 3899static void 3900linkmap_delete(Obj_Entry *obj) 3901{ 3902 struct link_map *l = &obj->linkmap; 3903 3904 if (l->l_prev == NULL) { 3905 if ((r_debug.r_map = l->l_next) != NULL) 3906 l->l_next->l_prev = NULL; 3907 return; 3908 } 3909 3910 if ((l->l_prev->l_next = l->l_next) != NULL) 3911 l->l_next->l_prev = l->l_prev; 3912} 3913 3914/* 3915 * Function for the debugger to set a breakpoint on to gain control. 3916 * 3917 * The two parameters allow the debugger to easily find and determine 3918 * what the runtime loader is doing and to whom it is doing it. 3919 * 3920 * When the loadhook trap is hit (r_debug_state, set at program 3921 * initialization), the arguments can be found on the stack: 3922 * 3923 * +8 struct link_map *m 3924 * +4 struct r_debug *rd 3925 * +0 RetAddr 3926 */ 3927void 3928r_debug_state(struct r_debug* rd, struct link_map *m) 3929{ 3930 /* 3931 * The following is a hack to force the compiler to emit calls to 3932 * this function, even when optimizing. If the function is empty, 3933 * the compiler is not obliged to emit any code for calls to it, 3934 * even when marked __noinline. However, gdb depends on those 3935 * calls being made. 3936 */ 3937 __compiler_membar(); 3938} 3939 3940/* 3941 * A function called after init routines have completed. This can be used to 3942 * break before a program's entry routine is called, and can be used when 3943 * main is not available in the symbol table. 3944 */ 3945void 3946_r_debug_postinit(struct link_map *m) 3947{ 3948 3949 /* See r_debug_state(). */ 3950 __compiler_membar(); 3951} 3952 3953static void 3954release_object(Obj_Entry *obj) 3955{ 3956 3957 if (obj->holdcount > 0) { 3958 obj->unholdfree = true; 3959 return; 3960 } 3961 munmap(obj->mapbase, obj->mapsize); 3962 linkmap_delete(obj); 3963 obj_free(obj); 3964} 3965 3966/* 3967 * Get address of the pointer variable in the main program. 3968 * Prefer non-weak symbol over the weak one. 3969 */ 3970static const void ** 3971get_program_var_addr(const char *name, RtldLockState *lockstate) 3972{ 3973 SymLook req; 3974 DoneList donelist; 3975 3976 symlook_init(&req, name); 3977 req.lockstate = lockstate; 3978 donelist_init(&donelist); 3979 if (symlook_global(&req, &donelist) != 0) 3980 return (NULL); 3981 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3982 return ((const void **)make_function_pointer(req.sym_out, 3983 req.defobj_out)); 3984 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3985 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3986 else 3987 return ((const void **)(req.defobj_out->relocbase + 3988 req.sym_out->st_value)); 3989} 3990 3991/* 3992 * Set a pointer variable in the main program to the given value. This 3993 * is used to set key variables such as "environ" before any of the 3994 * init functions are called. 3995 */ 3996static void 3997set_program_var(const char *name, const void *value) 3998{ 3999 const void **addr; 4000 4001 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4002 dbg("\"%s\": *%p <-- %p", name, addr, value); 4003 *addr = value; 4004 } 4005} 4006 4007/* 4008 * Search the global objects, including dependencies and main object, 4009 * for the given symbol. 4010 */ 4011static int 4012symlook_global(SymLook *req, DoneList *donelist) 4013{ 4014 SymLook req1; 4015 const Objlist_Entry *elm; 4016 int res; 4017 4018 symlook_init_from_req(&req1, req); 4019 4020 /* Search all objects loaded at program start up. */ 4021 if (req->defobj_out == NULL || 4022 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4023 res = symlook_list(&req1, &list_main, donelist); 4024 if (res == 0 && (req->defobj_out == NULL || 4025 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4026 req->sym_out = req1.sym_out; 4027 req->defobj_out = req1.defobj_out; 4028 assert(req->defobj_out != NULL); 4029 } 4030 } 4031 4032 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4033 STAILQ_FOREACH(elm, &list_global, link) { 4034 if (req->defobj_out != NULL && 4035 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4036 break; 4037 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4038 if (res == 0 && (req->defobj_out == NULL || 4039 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4040 req->sym_out = req1.sym_out; 4041 req->defobj_out = req1.defobj_out; 4042 assert(req->defobj_out != NULL); 4043 } 4044 } 4045 4046 return (req->sym_out != NULL ? 0 : ESRCH); 4047} 4048 4049/* 4050 * Given a symbol name in a referencing object, find the corresponding 4051 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4052 * no definition was found. Returns a pointer to the Obj_Entry of the 4053 * defining object via the reference parameter DEFOBJ_OUT. 4054 */ 4055static int 4056symlook_default(SymLook *req, const Obj_Entry *refobj) 4057{ 4058 DoneList donelist; 4059 const Objlist_Entry *elm; 4060 SymLook req1; 4061 int res; 4062 4063 donelist_init(&donelist); 4064 symlook_init_from_req(&req1, req); 4065 4066 /* 4067 * Look first in the referencing object if linked symbolically, 4068 * and similarly handle protected symbols. 4069 */ 4070 res = symlook_obj(&req1, refobj); 4071 if (res == 0 && (refobj->symbolic || 4072 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4073 req->sym_out = req1.sym_out; 4074 req->defobj_out = req1.defobj_out; 4075 assert(req->defobj_out != NULL); 4076 } 4077 if (refobj->symbolic || req->defobj_out != NULL) 4078 donelist_check(&donelist, refobj); 4079 4080 symlook_global(req, &donelist); 4081 4082 /* Search all dlopened DAGs containing the referencing object. */ 4083 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4084 if (req->sym_out != NULL && 4085 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4086 break; 4087 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4088 if (res == 0 && (req->sym_out == NULL || 4089 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4090 req->sym_out = req1.sym_out; 4091 req->defobj_out = req1.defobj_out; 4092 assert(req->defobj_out != NULL); 4093 } 4094 } 4095 4096 /* 4097 * Search the dynamic linker itself, and possibly resolve the 4098 * symbol from there. This is how the application links to 4099 * dynamic linker services such as dlopen. 4100 */ 4101 if (req->sym_out == NULL || 4102 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4103 res = symlook_obj(&req1, &obj_rtld); 4104 if (res == 0) { 4105 req->sym_out = req1.sym_out; 4106 req->defobj_out = req1.defobj_out; 4107 assert(req->defobj_out != NULL); 4108 } 4109 } 4110 4111 return (req->sym_out != NULL ? 0 : ESRCH); 4112} 4113 4114static int 4115symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4116{ 4117 const Elf_Sym *def; 4118 const Obj_Entry *defobj; 4119 const Objlist_Entry *elm; 4120 SymLook req1; 4121 int res; 4122 4123 def = NULL; 4124 defobj = NULL; 4125 STAILQ_FOREACH(elm, objlist, link) { 4126 if (donelist_check(dlp, elm->obj)) 4127 continue; 4128 symlook_init_from_req(&req1, req); 4129 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4130 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4131 def = req1.sym_out; 4132 defobj = req1.defobj_out; 4133 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4134 break; 4135 } 4136 } 4137 } 4138 if (def != NULL) { 4139 req->sym_out = def; 4140 req->defobj_out = defobj; 4141 return (0); 4142 } 4143 return (ESRCH); 4144} 4145 4146/* 4147 * Search the chain of DAGS cointed to by the given Needed_Entry 4148 * for a symbol of the given name. Each DAG is scanned completely 4149 * before advancing to the next one. Returns a pointer to the symbol, 4150 * or NULL if no definition was found. 4151 */ 4152static int 4153symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4154{ 4155 const Elf_Sym *def; 4156 const Needed_Entry *n; 4157 const Obj_Entry *defobj; 4158 SymLook req1; 4159 int res; 4160 4161 def = NULL; 4162 defobj = NULL; 4163 symlook_init_from_req(&req1, req); 4164 for (n = needed; n != NULL; n = n->next) { 4165 if (n->obj == NULL || 4166 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4167 continue; 4168 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4169 def = req1.sym_out; 4170 defobj = req1.defobj_out; 4171 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4172 break; 4173 } 4174 } 4175 if (def != NULL) { 4176 req->sym_out = def; 4177 req->defobj_out = defobj; 4178 return (0); 4179 } 4180 return (ESRCH); 4181} 4182 4183/* 4184 * Search the symbol table of a single shared object for a symbol of 4185 * the given name and version, if requested. Returns a pointer to the 4186 * symbol, or NULL if no definition was found. If the object is 4187 * filter, return filtered symbol from filtee. 4188 * 4189 * The symbol's hash value is passed in for efficiency reasons; that 4190 * eliminates many recomputations of the hash value. 4191 */ 4192int 4193symlook_obj(SymLook *req, const Obj_Entry *obj) 4194{ 4195 DoneList donelist; 4196 SymLook req1; 4197 int flags, res, mres; 4198 4199 /* 4200 * If there is at least one valid hash at this point, we prefer to 4201 * use the faster GNU version if available. 4202 */ 4203 if (obj->valid_hash_gnu) 4204 mres = symlook_obj1_gnu(req, obj); 4205 else if (obj->valid_hash_sysv) 4206 mres = symlook_obj1_sysv(req, obj); 4207 else 4208 return (EINVAL); 4209 4210 if (mres == 0) { 4211 if (obj->needed_filtees != NULL) { 4212 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4213 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4214 donelist_init(&donelist); 4215 symlook_init_from_req(&req1, req); 4216 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4217 if (res == 0) { 4218 req->sym_out = req1.sym_out; 4219 req->defobj_out = req1.defobj_out; 4220 } 4221 return (res); 4222 } 4223 if (obj->needed_aux_filtees != NULL) { 4224 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4225 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4226 donelist_init(&donelist); 4227 symlook_init_from_req(&req1, req); 4228 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4229 if (res == 0) { 4230 req->sym_out = req1.sym_out; 4231 req->defobj_out = req1.defobj_out; 4232 return (res); 4233 } 4234 } 4235 } 4236 return (mres); 4237} 4238 4239/* Symbol match routine common to both hash functions */ 4240static bool 4241matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4242 const unsigned long symnum) 4243{ 4244 Elf_Versym verndx; 4245 const Elf_Sym *symp; 4246 const char *strp; 4247 4248 symp = obj->symtab + symnum; 4249 strp = obj->strtab + symp->st_name; 4250 4251 switch (ELF_ST_TYPE(symp->st_info)) { 4252 case STT_FUNC: 4253 case STT_NOTYPE: 4254 case STT_OBJECT: 4255 case STT_COMMON: 4256 case STT_GNU_IFUNC: 4257 if (symp->st_value == 0) 4258 return (false); 4259 /* fallthrough */ 4260 case STT_TLS: 4261 if (symp->st_shndx != SHN_UNDEF) 4262 break; 4263#ifndef __mips__ 4264 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4265 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4266 break; 4267 /* fallthrough */ 4268#endif 4269 default: 4270 return (false); 4271 } 4272 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4273 return (false); 4274 4275 if (req->ventry == NULL) { 4276 if (obj->versyms != NULL) { 4277 verndx = VER_NDX(obj->versyms[symnum]); 4278 if (verndx > obj->vernum) { 4279 _rtld_error( 4280 "%s: symbol %s references wrong version %d", 4281 obj->path, obj->strtab + symnum, verndx); 4282 return (false); 4283 } 4284 /* 4285 * If we are not called from dlsym (i.e. this 4286 * is a normal relocation from unversioned 4287 * binary), accept the symbol immediately if 4288 * it happens to have first version after this 4289 * shared object became versioned. Otherwise, 4290 * if symbol is versioned and not hidden, 4291 * remember it. If it is the only symbol with 4292 * this name exported by the shared object, it 4293 * will be returned as a match by the calling 4294 * function. If symbol is global (verndx < 2) 4295 * accept it unconditionally. 4296 */ 4297 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4298 verndx == VER_NDX_GIVEN) { 4299 result->sym_out = symp; 4300 return (true); 4301 } 4302 else if (verndx >= VER_NDX_GIVEN) { 4303 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4304 == 0) { 4305 if (result->vsymp == NULL) 4306 result->vsymp = symp; 4307 result->vcount++; 4308 } 4309 return (false); 4310 } 4311 } 4312 result->sym_out = symp; 4313 return (true); 4314 } 4315 if (obj->versyms == NULL) { 4316 if (object_match_name(obj, req->ventry->name)) { 4317 _rtld_error("%s: object %s should provide version %s " 4318 "for symbol %s", obj_rtld.path, obj->path, 4319 req->ventry->name, obj->strtab + symnum); 4320 return (false); 4321 } 4322 } else { 4323 verndx = VER_NDX(obj->versyms[symnum]); 4324 if (verndx > obj->vernum) { 4325 _rtld_error("%s: symbol %s references wrong version %d", 4326 obj->path, obj->strtab + symnum, verndx); 4327 return (false); 4328 } 4329 if (obj->vertab[verndx].hash != req->ventry->hash || 4330 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4331 /* 4332 * Version does not match. Look if this is a 4333 * global symbol and if it is not hidden. If 4334 * global symbol (verndx < 2) is available, 4335 * use it. Do not return symbol if we are 4336 * called by dlvsym, because dlvsym looks for 4337 * a specific version and default one is not 4338 * what dlvsym wants. 4339 */ 4340 if ((req->flags & SYMLOOK_DLSYM) || 4341 (verndx >= VER_NDX_GIVEN) || 4342 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4343 return (false); 4344 } 4345 } 4346 result->sym_out = symp; 4347 return (true); 4348} 4349 4350/* 4351 * Search for symbol using SysV hash function. 4352 * obj->buckets is known not to be NULL at this point; the test for this was 4353 * performed with the obj->valid_hash_sysv assignment. 4354 */ 4355static int 4356symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4357{ 4358 unsigned long symnum; 4359 Sym_Match_Result matchres; 4360 4361 matchres.sym_out = NULL; 4362 matchres.vsymp = NULL; 4363 matchres.vcount = 0; 4364 4365 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4366 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4367 if (symnum >= obj->nchains) 4368 return (ESRCH); /* Bad object */ 4369 4370 if (matched_symbol(req, obj, &matchres, symnum)) { 4371 req->sym_out = matchres.sym_out; 4372 req->defobj_out = obj; 4373 return (0); 4374 } 4375 } 4376 if (matchres.vcount == 1) { 4377 req->sym_out = matchres.vsymp; 4378 req->defobj_out = obj; 4379 return (0); 4380 } 4381 return (ESRCH); 4382} 4383 4384/* Search for symbol using GNU hash function */ 4385static int 4386symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4387{ 4388 Elf_Addr bloom_word; 4389 const Elf32_Word *hashval; 4390 Elf32_Word bucket; 4391 Sym_Match_Result matchres; 4392 unsigned int h1, h2; 4393 unsigned long symnum; 4394 4395 matchres.sym_out = NULL; 4396 matchres.vsymp = NULL; 4397 matchres.vcount = 0; 4398 4399 /* Pick right bitmask word from Bloom filter array */ 4400 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4401 obj->maskwords_bm_gnu]; 4402 4403 /* Calculate modulus word size of gnu hash and its derivative */ 4404 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4405 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4406 4407 /* Filter out the "definitely not in set" queries */ 4408 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4409 return (ESRCH); 4410 4411 /* Locate hash chain and corresponding value element*/ 4412 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4413 if (bucket == 0) 4414 return (ESRCH); 4415 hashval = &obj->chain_zero_gnu[bucket]; 4416 do { 4417 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4418 symnum = hashval - obj->chain_zero_gnu; 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 } while ((*hashval++ & 1) == 0); 4426 if (matchres.vcount == 1) { 4427 req->sym_out = matchres.vsymp; 4428 req->defobj_out = obj; 4429 return (0); 4430 } 4431 return (ESRCH); 4432} 4433 4434static void 4435trace_loaded_objects(Obj_Entry *obj) 4436{ 4437 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4438 int c; 4439 4440 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4441 main_local = ""; 4442 4443 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4444 fmt1 = "\t%o => %p (%x)\n"; 4445 4446 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4447 fmt2 = "\t%o (%x)\n"; 4448 4449 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4450 4451 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4452 Needed_Entry *needed; 4453 char *name, *path; 4454 bool is_lib; 4455 4456 if (obj->marker) 4457 continue; 4458 if (list_containers && obj->needed != NULL) 4459 rtld_printf("%s:\n", obj->path); 4460 for (needed = obj->needed; needed; needed = needed->next) { 4461 if (needed->obj != NULL) { 4462 if (needed->obj->traced && !list_containers) 4463 continue; 4464 needed->obj->traced = true; 4465 path = needed->obj->path; 4466 } else 4467 path = "not found"; 4468 4469 name = (char *)obj->strtab + needed->name; 4470 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4471 4472 fmt = is_lib ? fmt1 : fmt2; 4473 while ((c = *fmt++) != '\0') { 4474 switch (c) { 4475 default: 4476 rtld_putchar(c); 4477 continue; 4478 case '\\': 4479 switch (c = *fmt) { 4480 case '\0': 4481 continue; 4482 case 'n': 4483 rtld_putchar('\n'); 4484 break; 4485 case 't': 4486 rtld_putchar('\t'); 4487 break; 4488 } 4489 break; 4490 case '%': 4491 switch (c = *fmt) { 4492 case '\0': 4493 continue; 4494 case '%': 4495 default: 4496 rtld_putchar(c); 4497 break; 4498 case 'A': 4499 rtld_putstr(main_local); 4500 break; 4501 case 'a': 4502 rtld_putstr(obj_main->path); 4503 break; 4504 case 'o': 4505 rtld_putstr(name); 4506 break; 4507#if 0 4508 case 'm': 4509 rtld_printf("%d", sodp->sod_major); 4510 break; 4511 case 'n': 4512 rtld_printf("%d", sodp->sod_minor); 4513 break; 4514#endif 4515 case 'p': 4516 rtld_putstr(path); 4517 break; 4518 case 'x': 4519 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4520 0); 4521 break; 4522 } 4523 break; 4524 } 4525 ++fmt; 4526 } 4527 } 4528 } 4529} 4530 4531/* 4532 * Unload a dlopened object and its dependencies from memory and from 4533 * our data structures. It is assumed that the DAG rooted in the 4534 * object has already been unreferenced, and that the object has a 4535 * reference count of 0. 4536 */ 4537static void 4538unload_object(Obj_Entry *root, RtldLockState *lockstate) 4539{ 4540 Obj_Entry marker, *obj, *next; 4541 4542 assert(root->refcount == 0); 4543 4544 /* 4545 * Pass over the DAG removing unreferenced objects from 4546 * appropriate lists. 4547 */ 4548 unlink_object(root); 4549 4550 /* Unmap all objects that are no longer referenced. */ 4551 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4552 next = TAILQ_NEXT(obj, next); 4553 if (obj->marker || obj->refcount != 0) 4554 continue; 4555 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4556 obj->mapsize, 0, obj->path); 4557 dbg("unloading \"%s\"", obj->path); 4558 /* 4559 * Unlink the object now to prevent new references from 4560 * being acquired while the bind lock is dropped in 4561 * recursive dlclose() invocations. 4562 */ 4563 TAILQ_REMOVE(&obj_list, obj, next); 4564 obj_count--; 4565 4566 if (obj->filtees_loaded) { 4567 if (next != NULL) { 4568 init_marker(&marker); 4569 TAILQ_INSERT_BEFORE(next, &marker, next); 4570 unload_filtees(obj, lockstate); 4571 next = TAILQ_NEXT(&marker, next); 4572 TAILQ_REMOVE(&obj_list, &marker, next); 4573 } else 4574 unload_filtees(obj, lockstate); 4575 } 4576 release_object(obj); 4577 } 4578} 4579 4580static void 4581unlink_object(Obj_Entry *root) 4582{ 4583 Objlist_Entry *elm; 4584 4585 if (root->refcount == 0) { 4586 /* Remove the object from the RTLD_GLOBAL list. */ 4587 objlist_remove(&list_global, root); 4588 4589 /* Remove the object from all objects' DAG lists. */ 4590 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4591 objlist_remove(&elm->obj->dldags, root); 4592 if (elm->obj != root) 4593 unlink_object(elm->obj); 4594 } 4595 } 4596} 4597 4598static void 4599ref_dag(Obj_Entry *root) 4600{ 4601 Objlist_Entry *elm; 4602 4603 assert(root->dag_inited); 4604 STAILQ_FOREACH(elm, &root->dagmembers, link) 4605 elm->obj->refcount++; 4606} 4607 4608static void 4609unref_dag(Obj_Entry *root) 4610{ 4611 Objlist_Entry *elm; 4612 4613 assert(root->dag_inited); 4614 STAILQ_FOREACH(elm, &root->dagmembers, link) 4615 elm->obj->refcount--; 4616} 4617 4618/* 4619 * Common code for MD __tls_get_addr(). 4620 */ 4621static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4622static void * 4623tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4624{ 4625 Elf_Addr *newdtv, *dtv; 4626 RtldLockState lockstate; 4627 int to_copy; 4628 4629 dtv = *dtvp; 4630 /* Check dtv generation in case new modules have arrived */ 4631 if (dtv[0] != tls_dtv_generation) { 4632 wlock_acquire(rtld_bind_lock, &lockstate); 4633 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4634 to_copy = dtv[1]; 4635 if (to_copy > tls_max_index) 4636 to_copy = tls_max_index; 4637 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4638 newdtv[0] = tls_dtv_generation; 4639 newdtv[1] = tls_max_index; 4640 free(dtv); 4641 lock_release(rtld_bind_lock, &lockstate); 4642 dtv = *dtvp = newdtv; 4643 } 4644 4645 /* Dynamically allocate module TLS if necessary */ 4646 if (dtv[index + 1] == 0) { 4647 /* Signal safe, wlock will block out signals. */ 4648 wlock_acquire(rtld_bind_lock, &lockstate); 4649 if (!dtv[index + 1]) 4650 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4651 lock_release(rtld_bind_lock, &lockstate); 4652 } 4653 return ((void *)(dtv[index + 1] + offset)); 4654} 4655 4656void * 4657tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4658{ 4659 Elf_Addr *dtv; 4660 4661 dtv = *dtvp; 4662 /* Check dtv generation in case new modules have arrived */ 4663 if (__predict_true(dtv[0] == tls_dtv_generation && 4664 dtv[index + 1] != 0)) 4665 return ((void *)(dtv[index + 1] + offset)); 4666 return (tls_get_addr_slow(dtvp, index, offset)); 4667} 4668 4669#if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4670 defined(__powerpc__) || defined(__riscv__) 4671 4672/* 4673 * Allocate Static TLS using the Variant I method. 4674 */ 4675void * 4676allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4677{ 4678 Obj_Entry *obj; 4679 char *tcb; 4680 Elf_Addr **tls; 4681 Elf_Addr *dtv; 4682 Elf_Addr addr; 4683 int i; 4684 4685 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4686 return (oldtcb); 4687 4688 assert(tcbsize >= TLS_TCB_SIZE); 4689 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4690 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4691 4692 if (oldtcb != NULL) { 4693 memcpy(tls, oldtcb, tls_static_space); 4694 free(oldtcb); 4695 4696 /* Adjust the DTV. */ 4697 dtv = tls[0]; 4698 for (i = 0; i < dtv[1]; i++) { 4699 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4700 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4701 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4702 } 4703 } 4704 } else { 4705 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4706 tls[0] = dtv; 4707 dtv[0] = tls_dtv_generation; 4708 dtv[1] = tls_max_index; 4709 4710 for (obj = globallist_curr(objs); obj != NULL; 4711 obj = globallist_next(obj)) { 4712 if (obj->tlsoffset > 0) { 4713 addr = (Elf_Addr)tls + obj->tlsoffset; 4714 if (obj->tlsinitsize > 0) 4715 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4716 if (obj->tlssize > obj->tlsinitsize) 4717 memset((void*) (addr + obj->tlsinitsize), 0, 4718 obj->tlssize - obj->tlsinitsize); 4719 dtv[obj->tlsindex + 1] = addr; 4720 } 4721 } 4722 } 4723 4724 return (tcb); 4725} 4726 4727void 4728free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4729{ 4730 Elf_Addr *dtv; 4731 Elf_Addr tlsstart, tlsend; 4732 int dtvsize, i; 4733 4734 assert(tcbsize >= TLS_TCB_SIZE); 4735 4736 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4737 tlsend = tlsstart + tls_static_space; 4738 4739 dtv = *(Elf_Addr **)tlsstart; 4740 dtvsize = dtv[1]; 4741 for (i = 0; i < dtvsize; i++) { 4742 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4743 free((void*)dtv[i+2]); 4744 } 4745 } 4746 free(dtv); 4747 free(tcb); 4748} 4749 4750#endif 4751 4752#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4753 4754/* 4755 * Allocate Static TLS using the Variant II method. 4756 */ 4757void * 4758allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4759{ 4760 Obj_Entry *obj; 4761 size_t size, ralign; 4762 char *tls; 4763 Elf_Addr *dtv, *olddtv; 4764 Elf_Addr segbase, oldsegbase, addr; 4765 int i; 4766 4767 ralign = tcbalign; 4768 if (tls_static_max_align > ralign) 4769 ralign = tls_static_max_align; 4770 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4771 4772 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4773 tls = malloc_aligned(size, ralign); 4774 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4775 4776 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4777 ((Elf_Addr*)segbase)[0] = segbase; 4778 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4779 4780 dtv[0] = tls_dtv_generation; 4781 dtv[1] = tls_max_index; 4782 4783 if (oldtls) { 4784 /* 4785 * Copy the static TLS block over whole. 4786 */ 4787 oldsegbase = (Elf_Addr) oldtls; 4788 memcpy((void *)(segbase - tls_static_space), 4789 (const void *)(oldsegbase - tls_static_space), 4790 tls_static_space); 4791 4792 /* 4793 * If any dynamic TLS blocks have been created tls_get_addr(), 4794 * move them over. 4795 */ 4796 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4797 for (i = 0; i < olddtv[1]; i++) { 4798 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4799 dtv[i+2] = olddtv[i+2]; 4800 olddtv[i+2] = 0; 4801 } 4802 } 4803 4804 /* 4805 * We assume that this block was the one we created with 4806 * allocate_initial_tls(). 4807 */ 4808 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4809 } else { 4810 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4811 if (obj->marker || obj->tlsoffset == 0) 4812 continue; 4813 addr = segbase - obj->tlsoffset; 4814 memset((void*) (addr + obj->tlsinitsize), 4815 0, obj->tlssize - obj->tlsinitsize); 4816 if (obj->tlsinit) 4817 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4818 dtv[obj->tlsindex + 1] = addr; 4819 } 4820 } 4821 4822 return (void*) segbase; 4823} 4824 4825void 4826free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4827{ 4828 Elf_Addr* dtv; 4829 size_t size, ralign; 4830 int dtvsize, i; 4831 Elf_Addr tlsstart, tlsend; 4832 4833 /* 4834 * Figure out the size of the initial TLS block so that we can 4835 * find stuff which ___tls_get_addr() allocated dynamically. 4836 */ 4837 ralign = tcbalign; 4838 if (tls_static_max_align > ralign) 4839 ralign = tls_static_max_align; 4840 size = round(tls_static_space, ralign); 4841 4842 dtv = ((Elf_Addr**)tls)[1]; 4843 dtvsize = dtv[1]; 4844 tlsend = (Elf_Addr) tls; 4845 tlsstart = tlsend - size; 4846 for (i = 0; i < dtvsize; i++) { 4847 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4848 free_aligned((void *)dtv[i + 2]); 4849 } 4850 } 4851 4852 free_aligned((void *)tlsstart); 4853 free((void*) dtv); 4854} 4855 4856#endif 4857 4858/* 4859 * Allocate TLS block for module with given index. 4860 */ 4861void * 4862allocate_module_tls(int index) 4863{ 4864 Obj_Entry* obj; 4865 char* p; 4866 4867 TAILQ_FOREACH(obj, &obj_list, next) { 4868 if (obj->marker) 4869 continue; 4870 if (obj->tlsindex == index) 4871 break; 4872 } 4873 if (!obj) { 4874 _rtld_error("Can't find module with TLS index %d", index); 4875 rtld_die(); 4876 } 4877 4878 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4879 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4880 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4881 4882 return p; 4883} 4884 4885bool 4886allocate_tls_offset(Obj_Entry *obj) 4887{ 4888 size_t off; 4889 4890 if (obj->tls_done) 4891 return true; 4892 4893 if (obj->tlssize == 0) { 4894 obj->tls_done = true; 4895 return true; 4896 } 4897 4898 if (tls_last_offset == 0) 4899 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4900 else 4901 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4902 obj->tlssize, obj->tlsalign); 4903 4904 /* 4905 * If we have already fixed the size of the static TLS block, we 4906 * must stay within that size. When allocating the static TLS, we 4907 * leave a small amount of space spare to be used for dynamically 4908 * loading modules which use static TLS. 4909 */ 4910 if (tls_static_space != 0) { 4911 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4912 return false; 4913 } else if (obj->tlsalign > tls_static_max_align) { 4914 tls_static_max_align = obj->tlsalign; 4915 } 4916 4917 tls_last_offset = obj->tlsoffset = off; 4918 tls_last_size = obj->tlssize; 4919 obj->tls_done = true; 4920 4921 return true; 4922} 4923 4924void 4925free_tls_offset(Obj_Entry *obj) 4926{ 4927 4928 /* 4929 * If we were the last thing to allocate out of the static TLS 4930 * block, we give our space back to the 'allocator'. This is a 4931 * simplistic workaround to allow libGL.so.1 to be loaded and 4932 * unloaded multiple times. 4933 */ 4934 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4935 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4936 tls_last_offset -= obj->tlssize; 4937 tls_last_size = 0; 4938 } 4939} 4940 4941void * 4942_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4943{ 4944 void *ret; 4945 RtldLockState lockstate; 4946 4947 wlock_acquire(rtld_bind_lock, &lockstate); 4948 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4949 tcbsize, tcbalign); 4950 lock_release(rtld_bind_lock, &lockstate); 4951 return (ret); 4952} 4953 4954void 4955_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4956{ 4957 RtldLockState lockstate; 4958 4959 wlock_acquire(rtld_bind_lock, &lockstate); 4960 free_tls(tcb, tcbsize, tcbalign); 4961 lock_release(rtld_bind_lock, &lockstate); 4962} 4963 4964static void 4965object_add_name(Obj_Entry *obj, const char *name) 4966{ 4967 Name_Entry *entry; 4968 size_t len; 4969 4970 len = strlen(name); 4971 entry = malloc(sizeof(Name_Entry) + len); 4972 4973 if (entry != NULL) { 4974 strcpy(entry->name, name); 4975 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4976 } 4977} 4978 4979static int 4980object_match_name(const Obj_Entry *obj, const char *name) 4981{ 4982 Name_Entry *entry; 4983 4984 STAILQ_FOREACH(entry, &obj->names, link) { 4985 if (strcmp(name, entry->name) == 0) 4986 return (1); 4987 } 4988 return (0); 4989} 4990 4991static Obj_Entry * 4992locate_dependency(const Obj_Entry *obj, const char *name) 4993{ 4994 const Objlist_Entry *entry; 4995 const Needed_Entry *needed; 4996 4997 STAILQ_FOREACH(entry, &list_main, link) { 4998 if (object_match_name(entry->obj, name)) 4999 return entry->obj; 5000 } 5001 5002 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5003 if (strcmp(obj->strtab + needed->name, name) == 0 || 5004 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5005 /* 5006 * If there is DT_NEEDED for the name we are looking for, 5007 * we are all set. Note that object might not be found if 5008 * dependency was not loaded yet, so the function can 5009 * return NULL here. This is expected and handled 5010 * properly by the caller. 5011 */ 5012 return (needed->obj); 5013 } 5014 } 5015 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5016 obj->path, name); 5017 rtld_die(); 5018} 5019 5020static int 5021check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5022 const Elf_Vernaux *vna) 5023{ 5024 const Elf_Verdef *vd; 5025 const char *vername; 5026 5027 vername = refobj->strtab + vna->vna_name; 5028 vd = depobj->verdef; 5029 if (vd == NULL) { 5030 _rtld_error("%s: version %s required by %s not defined", 5031 depobj->path, vername, refobj->path); 5032 return (-1); 5033 } 5034 for (;;) { 5035 if (vd->vd_version != VER_DEF_CURRENT) { 5036 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5037 depobj->path, vd->vd_version); 5038 return (-1); 5039 } 5040 if (vna->vna_hash == vd->vd_hash) { 5041 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5042 ((char *)vd + vd->vd_aux); 5043 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5044 return (0); 5045 } 5046 if (vd->vd_next == 0) 5047 break; 5048 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5049 } 5050 if (vna->vna_flags & VER_FLG_WEAK) 5051 return (0); 5052 _rtld_error("%s: version %s required by %s not found", 5053 depobj->path, vername, refobj->path); 5054 return (-1); 5055} 5056 5057static int 5058rtld_verify_object_versions(Obj_Entry *obj) 5059{ 5060 const Elf_Verneed *vn; 5061 const Elf_Verdef *vd; 5062 const Elf_Verdaux *vda; 5063 const Elf_Vernaux *vna; 5064 const Obj_Entry *depobj; 5065 int maxvernum, vernum; 5066 5067 if (obj->ver_checked) 5068 return (0); 5069 obj->ver_checked = true; 5070 5071 maxvernum = 0; 5072 /* 5073 * Walk over defined and required version records and figure out 5074 * max index used by any of them. Do very basic sanity checking 5075 * while there. 5076 */ 5077 vn = obj->verneed; 5078 while (vn != NULL) { 5079 if (vn->vn_version != VER_NEED_CURRENT) { 5080 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5081 obj->path, vn->vn_version); 5082 return (-1); 5083 } 5084 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5085 for (;;) { 5086 vernum = VER_NEED_IDX(vna->vna_other); 5087 if (vernum > maxvernum) 5088 maxvernum = vernum; 5089 if (vna->vna_next == 0) 5090 break; 5091 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5092 } 5093 if (vn->vn_next == 0) 5094 break; 5095 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5096 } 5097 5098 vd = obj->verdef; 5099 while (vd != NULL) { 5100 if (vd->vd_version != VER_DEF_CURRENT) { 5101 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5102 obj->path, vd->vd_version); 5103 return (-1); 5104 } 5105 vernum = VER_DEF_IDX(vd->vd_ndx); 5106 if (vernum > maxvernum) 5107 maxvernum = vernum; 5108 if (vd->vd_next == 0) 5109 break; 5110 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5111 } 5112 5113 if (maxvernum == 0) 5114 return (0); 5115 5116 /* 5117 * Store version information in array indexable by version index. 5118 * Verify that object version requirements are satisfied along the 5119 * way. 5120 */ 5121 obj->vernum = maxvernum + 1; 5122 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5123 5124 vd = obj->verdef; 5125 while (vd != NULL) { 5126 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5127 vernum = VER_DEF_IDX(vd->vd_ndx); 5128 assert(vernum <= maxvernum); 5129 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5130 obj->vertab[vernum].hash = vd->vd_hash; 5131 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5132 obj->vertab[vernum].file = NULL; 5133 obj->vertab[vernum].flags = 0; 5134 } 5135 if (vd->vd_next == 0) 5136 break; 5137 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5138 } 5139 5140 vn = obj->verneed; 5141 while (vn != NULL) { 5142 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5143 if (depobj == NULL) 5144 return (-1); 5145 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5146 for (;;) { 5147 if (check_object_provided_version(obj, depobj, vna)) 5148 return (-1); 5149 vernum = VER_NEED_IDX(vna->vna_other); 5150 assert(vernum <= maxvernum); 5151 obj->vertab[vernum].hash = vna->vna_hash; 5152 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5153 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5154 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5155 VER_INFO_HIDDEN : 0; 5156 if (vna->vna_next == 0) 5157 break; 5158 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5159 } 5160 if (vn->vn_next == 0) 5161 break; 5162 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5163 } 5164 return 0; 5165} 5166 5167static int 5168rtld_verify_versions(const Objlist *objlist) 5169{ 5170 Objlist_Entry *entry; 5171 int rc; 5172 5173 rc = 0; 5174 STAILQ_FOREACH(entry, objlist, link) { 5175 /* 5176 * Skip dummy objects or objects that have their version requirements 5177 * already checked. 5178 */ 5179 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5180 continue; 5181 if (rtld_verify_object_versions(entry->obj) == -1) { 5182 rc = -1; 5183 if (ld_tracing == NULL) 5184 break; 5185 } 5186 } 5187 if (rc == 0 || ld_tracing != NULL) 5188 rc = rtld_verify_object_versions(&obj_rtld); 5189 return rc; 5190} 5191 5192const Ver_Entry * 5193fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5194{ 5195 Elf_Versym vernum; 5196 5197 if (obj->vertab) { 5198 vernum = VER_NDX(obj->versyms[symnum]); 5199 if (vernum >= obj->vernum) { 5200 _rtld_error("%s: symbol %s has wrong verneed value %d", 5201 obj->path, obj->strtab + symnum, vernum); 5202 } else if (obj->vertab[vernum].hash != 0) { 5203 return &obj->vertab[vernum]; 5204 } 5205 } 5206 return NULL; 5207} 5208 5209int 5210_rtld_get_stack_prot(void) 5211{ 5212 5213 return (stack_prot); 5214} 5215 5216int 5217_rtld_is_dlopened(void *arg) 5218{ 5219 Obj_Entry *obj; 5220 RtldLockState lockstate; 5221 int res; 5222 5223 rlock_acquire(rtld_bind_lock, &lockstate); 5224 obj = dlcheck(arg); 5225 if (obj == NULL) 5226 obj = obj_from_addr(arg); 5227 if (obj == NULL) { 5228 _rtld_error("No shared object contains address"); 5229 lock_release(rtld_bind_lock, &lockstate); 5230 return (-1); 5231 } 5232 res = obj->dlopened ? 1 : 0; 5233 lock_release(rtld_bind_lock, &lockstate); 5234 return (res); 5235} 5236 5237int 5238obj_enforce_relro(Obj_Entry *obj) 5239{ 5240 5241 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5242 PROT_READ) == -1) { 5243 _rtld_error("%s: Cannot enforce relro protection: %s", 5244 obj->path, rtld_strerror(errno)); 5245 return (-1); 5246 } 5247 return (0); 5248} 5249 5250static void 5251map_stacks_exec(RtldLockState *lockstate) 5252{ 5253 void (*thr_map_stacks_exec)(void); 5254 5255 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5256 return; 5257 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5258 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5259 if (thr_map_stacks_exec != NULL) { 5260 stack_prot |= PROT_EXEC; 5261 thr_map_stacks_exec(); 5262 } 5263} 5264 5265void 5266symlook_init(SymLook *dst, const char *name) 5267{ 5268 5269 bzero(dst, sizeof(*dst)); 5270 dst->name = name; 5271 dst->hash = elf_hash(name); 5272 dst->hash_gnu = gnu_hash(name); 5273} 5274 5275static void 5276symlook_init_from_req(SymLook *dst, const SymLook *src) 5277{ 5278 5279 dst->name = src->name; 5280 dst->hash = src->hash; 5281 dst->hash_gnu = src->hash_gnu; 5282 dst->ventry = src->ventry; 5283 dst->flags = src->flags; 5284 dst->defobj_out = NULL; 5285 dst->sym_out = NULL; 5286 dst->lockstate = src->lockstate; 5287} 5288 5289static int 5290open_binary_fd(const char *argv0, bool search_in_path) 5291{ 5292 char *pathenv, *pe, binpath[PATH_MAX]; 5293 int fd; 5294 5295 if (search_in_path && strchr(argv0, '/') == NULL) { 5296 pathenv = getenv("PATH"); 5297 if (pathenv == NULL) { 5298 rtld_printf("-p and no PATH environment variable\n"); 5299 rtld_die(); 5300 } 5301 pathenv = strdup(pathenv); 5302 if (pathenv == NULL) { 5303 rtld_printf("Cannot allocate memory\n"); 5304 rtld_die(); 5305 } 5306 fd = -1; 5307 errno = ENOENT; 5308 while ((pe = strsep(&pathenv, ":")) != NULL) { 5309 if (strlcpy(binpath, pe, sizeof(binpath)) >= 5310 sizeof(binpath)) 5311 continue; 5312 if (binpath[0] != '\0' && 5313 strlcat(binpath, "/", sizeof(binpath)) >= 5314 sizeof(binpath)) 5315 continue; 5316 if (strlcat(binpath, argv0, sizeof(binpath)) >= 5317 sizeof(binpath)) 5318 continue; 5319 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5320 if (fd != -1 || errno != ENOENT) 5321 break; 5322 } 5323 free(pathenv); 5324 } else { 5325 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5326 } 5327 5328 if (fd == -1) { 5329 rtld_printf("Opening %s: %s\n", argv0, 5330 rtld_strerror(errno)); 5331 rtld_die(); 5332 } 5333 return (fd); 5334} 5335 5336/* 5337 * Parse a set of command-line arguments. 5338 */ 5339static int 5340parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5341{ 5342 const char *arg; 5343 int fd, i, j, arglen; 5344 char opt; 5345 5346 dbg("Parsing command-line arguments"); 5347 *use_pathp = false; 5348 *fdp = -1; 5349 5350 for (i = 1; i < argc; i++ ) { 5351 arg = argv[i]; 5352 dbg("argv[%d]: '%s'", i, arg); 5353 5354 /* 5355 * rtld arguments end with an explicit "--" or with the first 5356 * non-prefixed argument. 5357 */ 5358 if (strcmp(arg, "--") == 0) { 5359 i++; 5360 break; 5361 } 5362 if (arg[0] != '-') 5363 break; 5364 5365 /* 5366 * All other arguments are single-character options that can 5367 * be combined, so we need to search through `arg` for them. 5368 */ 5369 arglen = strlen(arg); 5370 for (j = 1; j < arglen; j++) { 5371 opt = arg[j]; 5372 if (opt == 'h') { 5373 print_usage(argv[0]); 5374 rtld_die(); 5375 } else if (opt == 'f') { 5376 /* 5377 * -f XX can be used to specify a descriptor for the 5378 * binary named at the command line (i.e., the later 5379 * argument will specify the process name but the 5380 * descriptor is what will actually be executed) 5381 */ 5382 if (j != arglen - 1) { 5383 /* -f must be the last option in, e.g., -abcf */ 5384 _rtld_error("invalid options: %s", arg); 5385 rtld_die(); 5386 } 5387 i++; 5388 fd = parse_integer(argv[i]); 5389 if (fd == -1) { 5390 _rtld_error("invalid file descriptor: '%s'", 5391 argv[i]); 5392 rtld_die(); 5393 } 5394 *fdp = fd; 5395 break; 5396 } else if (opt == 'p') { 5397 *use_pathp = true; 5398 } else { 5399 rtld_printf("invalid argument: '%s'\n", arg); 5400 print_usage(argv[0]); 5401 rtld_die(); 5402 } 5403 } 5404 } 5405 5406 return (i); 5407} 5408 5409/* 5410 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5411 */ 5412static int 5413parse_integer(const char *str) 5414{ 5415 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5416 const char *orig; 5417 int n; 5418 char c; 5419 5420 orig = str; 5421 n = 0; 5422 for (c = *str; c != '\0'; c = *++str) { 5423 if (c < '0' || c > '9') 5424 return (-1); 5425 5426 n *= RADIX; 5427 n += c - '0'; 5428 } 5429 5430 /* Make sure we actually parsed something. */ 5431 if (str == orig) 5432 return (-1); 5433 return (n); 5434} 5435 5436static void 5437print_usage(const char *argv0) 5438{ 5439 5440 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5441 "\n" 5442 "Options:\n" 5443 " -h Display this help message\n" 5444 " -p Search in PATH for named binary\n" 5445 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5446 " -- End of RTLD options\n" 5447 " <binary> Name of process to execute\n" 5448 " <args> Arguments to the executed process\n", argv0); 5449} 5450 5451/* 5452 * Overrides for libc_pic-provided functions. 5453 */ 5454 5455int 5456__getosreldate(void) 5457{ 5458 size_t len; 5459 int oid[2]; 5460 int error, osrel; 5461 5462 if (osreldate != 0) 5463 return (osreldate); 5464 5465 oid[0] = CTL_KERN; 5466 oid[1] = KERN_OSRELDATE; 5467 osrel = 0; 5468 len = sizeof(osrel); 5469 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5470 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5471 osreldate = osrel; 5472 return (osreldate); 5473} 5474 5475void 5476exit(int status) 5477{ 5478 5479 _exit(status); 5480} 5481 5482void (*__cleanup)(void); 5483int __isthreaded = 0; 5484int _thread_autoinit_dummy_decl = 1; 5485 5486/* 5487 * No unresolved symbols for rtld. 5488 */ 5489void 5490__pthread_cxa_finalize(struct dl_phdr_info *a) 5491{ 5492} 5493 5494void 5495__stack_chk_fail(void) 5496{ 5497 5498 _rtld_error("stack overflow detected; terminated"); 5499 rtld_die(); 5500} 5501__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5502 5503void 5504__chk_fail(void) 5505{ 5506 5507 _rtld_error("buffer overflow detected; terminated"); 5508 rtld_die(); 5509} 5510 5511const char * 5512rtld_strerror(int errnum) 5513{ 5514 5515 if (errnum < 0 || errnum >= sys_nerr) 5516 return ("Unknown error"); 5517 return (sys_errlist[errnum]); 5518} 5519