rtld.c revision 361382
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 361382 2020-05-22 13:18:43Z kib $"); 41 42#include <sys/param.h> 43#include <sys/mount.h> 44#include <sys/mman.h> 45#include <sys/stat.h> 46#include <sys/sysctl.h> 47#include <sys/uio.h> 48#include <sys/utsname.h> 49#include <sys/ktrace.h> 50 51#include <dlfcn.h> 52#include <err.h> 53#include <errno.h> 54#include <fcntl.h> 55#include <stdarg.h> 56#include <stdio.h> 57#include <stdlib.h> 58#include <string.h> 59#include <unistd.h> 60 61#include "debug.h" 62#include "rtld.h" 63#include "libmap.h" 64#include "paths.h" 65#include "rtld_tls.h" 66#include "rtld_printf.h" 67#include "rtld_utrace.h" 68#include "notes.h" 69 70/* Types. */ 71typedef void (*func_ptr_type)(); 72typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 73 74/* 75 * Function declarations. 76 */ 77static const char *basename(const char *); 78static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 79 const Elf_Dyn **, const Elf_Dyn **); 80static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 81 const Elf_Dyn *); 82static bool digest_dynamic(Obj_Entry *, int); 83static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 84static void distribute_static_tls(Objlist *, RtldLockState *); 85static Obj_Entry *dlcheck(void *); 86static int dlclose_locked(void *, RtldLockState *); 87static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 88 int lo_flags, int mode, RtldLockState *lockstate); 89static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 90static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 91static bool donelist_check(DoneList *, const Obj_Entry *); 92static void errmsg_restore(char *); 93static char *errmsg_save(void); 94static void *fill_search_info(const char *, size_t, void *); 95static char *find_library(const char *, const Obj_Entry *, int *); 96static const char *gethints(bool); 97static void hold_object(Obj_Entry *); 98static void unhold_object(Obj_Entry *); 99static void init_dag(Obj_Entry *); 100static void init_marker(Obj_Entry *); 101static void init_pagesizes(Elf_Auxinfo **aux_info); 102static void init_rtld(caddr_t, Elf_Auxinfo **); 103static void initlist_add_neededs(Needed_Entry *, Objlist *); 104static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 105static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); 106static void linkmap_add(Obj_Entry *); 107static void linkmap_delete(Obj_Entry *); 108static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 109static void unload_filtees(Obj_Entry *, RtldLockState *); 110static int load_needed_objects(Obj_Entry *, int); 111static int load_preload_objects(void); 112static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 113static void map_stacks_exec(RtldLockState *); 114static int obj_disable_relro(Obj_Entry *); 115static int obj_enforce_relro(Obj_Entry *); 116static Obj_Entry *obj_from_addr(const void *); 117static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 118static void objlist_call_init(Objlist *, RtldLockState *); 119static void objlist_clear(Objlist *); 120static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 121static void objlist_init(Objlist *); 122static void objlist_push_head(Objlist *, Obj_Entry *); 123static void objlist_push_tail(Objlist *, Obj_Entry *); 124static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 125static void objlist_remove(Objlist *, Obj_Entry *); 126static int open_binary_fd(const char *argv0, bool search_in_path, 127 const char **binpath_res); 128static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp); 129static int parse_integer(const char *); 130static void *path_enumerate(const char *, path_enum_proc, const char *, void *); 131static void print_usage(const char *argv0); 132static void release_object(Obj_Entry *); 133static int relocate_object_dag(Obj_Entry *root, bool bind_now, 134 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 135static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 136 int flags, RtldLockState *lockstate); 137static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 138 RtldLockState *); 139static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); 140static int rtld_dirname(const char *, char *); 141static int rtld_dirname_abs(const char *, char *); 142static void *rtld_dlopen(const char *name, int fd, int mode); 143static void rtld_exit(void); 144static void rtld_nop_exit(void); 145static char *search_library_path(const char *, const char *, const char *, 146 int *); 147static char *search_library_pathfds(const char *, const char *, int *); 148static const void **get_program_var_addr(const char *, RtldLockState *); 149static void set_program_var(const char *, const void *); 150static int symlook_default(SymLook *, const Obj_Entry *refobj); 151static int symlook_global(SymLook *, DoneList *); 152static void symlook_init_from_req(SymLook *, const SymLook *); 153static int symlook_list(SymLook *, const Objlist *, DoneList *); 154static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 155static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 156static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 157static void trace_loaded_objects(Obj_Entry *); 158static void unlink_object(Obj_Entry *); 159static void unload_object(Obj_Entry *, RtldLockState *lockstate); 160static void unref_dag(Obj_Entry *); 161static void ref_dag(Obj_Entry *); 162static char *origin_subst_one(Obj_Entry *, char *, const char *, 163 const char *, bool); 164static char *origin_subst(Obj_Entry *, char *); 165static bool obj_resolve_origin(Obj_Entry *obj); 166static void preinit_main(void); 167static int rtld_verify_versions(const Objlist *); 168static int rtld_verify_object_versions(Obj_Entry *); 169static void object_add_name(Obj_Entry *, const char *); 170static int object_match_name(const Obj_Entry *, const char *); 171static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 172static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 173 struct dl_phdr_info *phdr_info); 174static uint32_t gnu_hash(const char *); 175static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 176 const unsigned long); 177 178void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 179void _r_debug_postinit(struct link_map *) __noinline __exported; 180 181int __sys_openat(int, const char *, int, ...); 182 183/* 184 * Data declarations. 185 */ 186static char *error_message; /* Message for dlerror(), or NULL */ 187struct r_debug r_debug __exported; /* for GDB; */ 188static bool libmap_disable; /* Disable libmap */ 189static bool ld_loadfltr; /* Immediate filters processing */ 190static char *libmap_override; /* Maps to use in addition to libmap.conf */ 191static bool trust; /* False for setuid and setgid programs */ 192static bool dangerous_ld_env; /* True if environment variables have been 193 used to affect the libraries loaded */ 194bool ld_bind_not; /* Disable PLT update */ 195static char *ld_bind_now; /* Environment variable for immediate binding */ 196static char *ld_debug; /* Environment variable for debugging */ 197static char *ld_library_path; /* Environment variable for search path */ 198static char *ld_library_dirs; /* Environment variable for library descriptors */ 199static char *ld_preload; /* Environment variable for libraries to 200 load first */ 201static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 202static char *ld_tracing; /* Called from ldd to print libs */ 203static char *ld_utrace; /* Use utrace() to log events. */ 204static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 205static Obj_Entry *obj_main; /* The main program shared object */ 206static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 207static unsigned int obj_count; /* Number of objects in obj_list */ 208static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 209 210static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 211 STAILQ_HEAD_INITIALIZER(list_global); 212static Objlist list_main = /* Objects loaded at program startup */ 213 STAILQ_HEAD_INITIALIZER(list_main); 214static Objlist list_fini = /* Objects needing fini() calls */ 215 STAILQ_HEAD_INITIALIZER(list_fini); 216 217Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 218 219#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 220 221extern Elf_Dyn _DYNAMIC; 222#pragma weak _DYNAMIC 223 224int dlclose(void *) __exported; 225char *dlerror(void) __exported; 226void *dlopen(const char *, int) __exported; 227void *fdlopen(int, int) __exported; 228void *dlsym(void *, const char *) __exported; 229dlfunc_t dlfunc(void *, const char *) __exported; 230void *dlvsym(void *, const char *, const char *) __exported; 231int dladdr(const void *, Dl_info *) __exported; 232void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 233 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 234int dlinfo(void *, int , void *) __exported; 235int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 236int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 237int _rtld_get_stack_prot(void) __exported; 238int _rtld_is_dlopened(void *) __exported; 239void _rtld_error(const char *, ...) __exported; 240 241int npagesizes, osreldate; 242size_t *pagesizes; 243 244long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 245 246static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 247static int max_stack_flags; 248 249/* 250 * Global declarations normally provided by crt1. The dynamic linker is 251 * not built with crt1, so we have to provide them ourselves. 252 */ 253char *__progname; 254char **environ; 255 256/* 257 * Used to pass argc, argv to init functions. 258 */ 259int main_argc; 260char **main_argv; 261 262/* 263 * Globals to control TLS allocation. 264 */ 265size_t tls_last_offset; /* Static TLS offset of last module */ 266size_t tls_last_size; /* Static TLS size of last module */ 267size_t tls_static_space; /* Static TLS space allocated */ 268size_t tls_static_max_align; 269int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 270int tls_max_index = 1; /* Largest module index allocated */ 271 272bool ld_library_path_rpath = false; 273 274/* 275 * Globals for path names, and such 276 */ 277char *ld_elf_hints_default = _PATH_ELF_HINTS; 278char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 279char *ld_path_rtld = _PATH_RTLD; 280char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 281char *ld_env_prefix = LD_; 282 283static void (*rtld_exit_ptr)(void); 284 285/* 286 * Fill in a DoneList with an allocation large enough to hold all of 287 * the currently-loaded objects. Keep this as a macro since it calls 288 * alloca and we want that to occur within the scope of the caller. 289 */ 290#define donelist_init(dlp) \ 291 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 292 assert((dlp)->objs != NULL), \ 293 (dlp)->num_alloc = obj_count, \ 294 (dlp)->num_used = 0) 295 296#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 297 if (ld_utrace != NULL) \ 298 ld_utrace_log(e, h, mb, ms, r, n); \ 299} while (0) 300 301static void 302ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 303 int refcnt, const char *name) 304{ 305 struct utrace_rtld ut; 306 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG; 307 308 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); 309 ut.event = event; 310 ut.handle = handle; 311 ut.mapbase = mapbase; 312 ut.mapsize = mapsize; 313 ut.refcnt = refcnt; 314 bzero(ut.name, sizeof(ut.name)); 315 if (name) 316 strlcpy(ut.name, name, sizeof(ut.name)); 317 utrace(&ut, sizeof(ut)); 318} 319 320#ifdef RTLD_VARIANT_ENV_NAMES 321/* 322 * construct the env variable based on the type of binary that's 323 * running. 324 */ 325static inline const char * 326_LD(const char *var) 327{ 328 static char buffer[128]; 329 330 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 331 strlcat(buffer, var, sizeof(buffer)); 332 return (buffer); 333} 334#else 335#define _LD(x) LD_ x 336#endif 337 338/* 339 * Main entry point for dynamic linking. The first argument is the 340 * stack pointer. The stack is expected to be laid out as described 341 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 342 * Specifically, the stack pointer points to a word containing 343 * ARGC. Following that in the stack is a null-terminated sequence 344 * of pointers to argument strings. Then comes a null-terminated 345 * sequence of pointers to environment strings. Finally, there is a 346 * sequence of "auxiliary vector" entries. 347 * 348 * The second argument points to a place to store the dynamic linker's 349 * exit procedure pointer and the third to a place to store the main 350 * program's object. 351 * 352 * The return value is the main program's entry point. 353 */ 354func_ptr_type 355_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 356{ 357 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT]; 358 Objlist_Entry *entry; 359 Obj_Entry *last_interposer, *obj, *preload_tail; 360 const Elf_Phdr *phdr; 361 Objlist initlist; 362 RtldLockState lockstate; 363 struct stat st; 364 Elf_Addr *argcp; 365 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath; 366 const char *binpath; 367 caddr_t imgentry; 368 char buf[MAXPATHLEN]; 369 int argc, fd, i, mib[2], phnum, rtld_argc; 370 size_t len; 371 bool dir_enable, explicit_fd, search_in_path; 372 373 /* 374 * On entry, the dynamic linker itself has not been relocated yet. 375 * Be very careful not to reference any global data until after 376 * init_rtld has returned. It is OK to reference file-scope statics 377 * and string constants, and to call static and global functions. 378 */ 379 380 /* Find the auxiliary vector on the stack. */ 381 argcp = sp; 382 argc = *sp++; 383 argv = (char **) sp; 384 sp += argc + 1; /* Skip over arguments and NULL terminator */ 385 env = (char **) sp; 386 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 387 ; 388 aux = (Elf_Auxinfo *) sp; 389 390 /* Digest the auxiliary vector. */ 391 for (i = 0; i < AT_COUNT; i++) 392 aux_info[i] = NULL; 393 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 394 if (auxp->a_type < AT_COUNT) 395 aux_info[auxp->a_type] = auxp; 396 } 397 398 /* Initialize and relocate ourselves. */ 399 assert(aux_info[AT_BASE] != NULL); 400 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 401 402 __progname = obj_rtld.path; 403 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 404 environ = env; 405 main_argc = argc; 406 main_argv = argv; 407 408 if (aux_info[AT_CANARY] != NULL && 409 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 410 i = aux_info[AT_CANARYLEN]->a_un.a_val; 411 if (i > sizeof(__stack_chk_guard)) 412 i = sizeof(__stack_chk_guard); 413 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 414 } else { 415 mib[0] = CTL_KERN; 416 mib[1] = KERN_ARND; 417 418 len = sizeof(__stack_chk_guard); 419 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 420 len != sizeof(__stack_chk_guard)) { 421 /* If sysctl was unsuccessful, use the "terminator canary". */ 422 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 423 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 424 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 425 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 426 } 427 } 428 429 trust = !issetugid(); 430 431 md_abi_variant_hook(aux_info); 432 433 fd = -1; 434 if (aux_info[AT_EXECFD] != NULL) { 435 fd = aux_info[AT_EXECFD]->a_un.a_val; 436 } else { 437 assert(aux_info[AT_PHDR] != NULL); 438 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; 439 if (phdr == obj_rtld.phdr) { 440 if (!trust) { 441 rtld_printf("Tainted process refusing to run binary %s\n", 442 argv0); 443 rtld_die(); 444 } 445 dbg("opening main program in direct exec mode"); 446 if (argc >= 2) { 447 rtld_argc = parse_args(argv, argc, &search_in_path, &fd); 448 argv0 = argv[rtld_argc]; 449 explicit_fd = (fd != -1); 450 binpath = NULL; 451 if (!explicit_fd) 452 fd = open_binary_fd(argv0, search_in_path, &binpath); 453 if (fstat(fd, &st) == -1) { 454 _rtld_error("failed to fstat FD %d (%s): %s", fd, 455 explicit_fd ? "user-provided descriptor" : argv0, 456 rtld_strerror(errno)); 457 rtld_die(); 458 } 459 460 /* 461 * Rough emulation of the permission checks done by 462 * execve(2), only Unix DACs are checked, ACLs are 463 * ignored. Preserve the semantic of disabling owner 464 * to execute if owner x bit is cleared, even if 465 * others x bit is enabled. 466 * mmap(2) does not allow to mmap with PROT_EXEC if 467 * binary' file comes from noexec mount. We cannot 468 * set VV_TEXT on the binary. 469 */ 470 dir_enable = false; 471 if (st.st_uid == geteuid()) { 472 if ((st.st_mode & S_IXUSR) != 0) 473 dir_enable = true; 474 } else if (st.st_gid == getegid()) { 475 if ((st.st_mode & S_IXGRP) != 0) 476 dir_enable = true; 477 } else if ((st.st_mode & S_IXOTH) != 0) { 478 dir_enable = true; 479 } 480 if (!dir_enable) { 481 rtld_printf("No execute permission for binary %s\n", 482 argv0); 483 rtld_die(); 484 } 485 486 /* 487 * For direct exec mode, argv[0] is the interpreter 488 * name, we must remove it and shift arguments left 489 * before invoking binary main. Since stack layout 490 * places environment pointers and aux vectors right 491 * after the terminating NULL, we must shift 492 * environment and aux as well. 493 */ 494 main_argc = argc - rtld_argc; 495 for (i = 0; i <= main_argc; i++) 496 argv[i] = argv[i + rtld_argc]; 497 *argcp -= rtld_argc; 498 environ = env = envp = argv + main_argc + 1; 499 do { 500 *envp = *(envp + rtld_argc); 501 envp++; 502 } while (*envp != NULL); 503 aux = auxp = (Elf_Auxinfo *)envp; 504 auxpf = (Elf_Auxinfo *)(envp + rtld_argc); 505 /* XXXKIB insert place for AT_EXECPATH if not present */ 506 for (;; auxp++, auxpf++) { 507 *auxp = *auxpf; 508 if (auxp->a_type == AT_NULL) 509 break; 510 } 511 512 /* Point AT_EXECPATH auxv and aux_info to the binary path. */ 513 if (binpath == NULL) { 514 aux_info[AT_EXECPATH] = NULL; 515 } else { 516 if (aux_info[AT_EXECPATH] == NULL) { 517 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo)); 518 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; 519 } 520 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, 521 binpath); 522 } 523 } else { 524 rtld_printf("no binary\n"); 525 rtld_die(); 526 } 527 } 528 } 529 530 ld_bind_now = getenv(_LD("BIND_NOW")); 531 532 /* 533 * If the process is tainted, then we un-set the dangerous environment 534 * variables. The process will be marked as tainted until setuid(2) 535 * is called. If any child process calls setuid(2) we do not want any 536 * future processes to honor the potentially un-safe variables. 537 */ 538 if (!trust) { 539 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 540 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 541 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) || 542 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 543 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 544 _rtld_error("environment corrupt; aborting"); 545 rtld_die(); 546 } 547 } 548 ld_debug = getenv(_LD("DEBUG")); 549 if (ld_bind_now == NULL) 550 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL; 551 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 552 libmap_override = getenv(_LD("LIBMAP")); 553 ld_library_path = getenv(_LD("LIBRARY_PATH")); 554 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 555 ld_preload = getenv(_LD("PRELOAD")); 556 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 557 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 558 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 559 if (library_path_rpath != NULL) { 560 if (library_path_rpath[0] == 'y' || 561 library_path_rpath[0] == 'Y' || 562 library_path_rpath[0] == '1') 563 ld_library_path_rpath = true; 564 else 565 ld_library_path_rpath = false; 566 } 567 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 568 (ld_library_path != NULL) || (ld_preload != NULL) || 569 (ld_elf_hints_path != NULL) || ld_loadfltr; 570 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 571 ld_utrace = getenv(_LD("UTRACE")); 572 573 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 574 ld_elf_hints_path = ld_elf_hints_default; 575 576 if (ld_debug != NULL && *ld_debug != '\0') 577 debug = 1; 578 dbg("%s is initialized, base address = %p", __progname, 579 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 580 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 581 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 582 583 dbg("initializing thread locks"); 584 lockdflt_init(); 585 586 /* 587 * Load the main program, or process its program header if it is 588 * already loaded. 589 */ 590 if (fd != -1) { /* Load the main program. */ 591 dbg("loading main program"); 592 obj_main = map_object(fd, argv0, NULL); 593 close(fd); 594 if (obj_main == NULL) 595 rtld_die(); 596 max_stack_flags = obj_main->stack_flags; 597 } else { /* Main program already loaded. */ 598 dbg("processing main program's program header"); 599 assert(aux_info[AT_PHDR] != NULL); 600 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 601 assert(aux_info[AT_PHNUM] != NULL); 602 phnum = aux_info[AT_PHNUM]->a_un.a_val; 603 assert(aux_info[AT_PHENT] != NULL); 604 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 605 assert(aux_info[AT_ENTRY] != NULL); 606 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 607 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) 608 rtld_die(); 609 } 610 611 if (aux_info[AT_EXECPATH] != NULL && fd == -1) { 612 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 613 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 614 if (kexecpath[0] == '/') 615 obj_main->path = kexecpath; 616 else if (getcwd(buf, sizeof(buf)) == NULL || 617 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 618 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 619 obj_main->path = xstrdup(argv0); 620 else 621 obj_main->path = xstrdup(buf); 622 } else { 623 dbg("No AT_EXECPATH or direct exec"); 624 obj_main->path = xstrdup(argv0); 625 } 626 dbg("obj_main path %s", obj_main->path); 627 obj_main->mainprog = true; 628 629 if (aux_info[AT_STACKPROT] != NULL && 630 aux_info[AT_STACKPROT]->a_un.a_val != 0) 631 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 632 633#ifndef COMPAT_32BIT 634 /* 635 * Get the actual dynamic linker pathname from the executable if 636 * possible. (It should always be possible.) That ensures that 637 * gdb will find the right dynamic linker even if a non-standard 638 * one is being used. 639 */ 640 if (obj_main->interp != NULL && 641 strcmp(obj_main->interp, obj_rtld.path) != 0) { 642 free(obj_rtld.path); 643 obj_rtld.path = xstrdup(obj_main->interp); 644 __progname = obj_rtld.path; 645 } 646#endif 647 648 if (!digest_dynamic(obj_main, 0)) 649 rtld_die(); 650 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 651 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 652 obj_main->dynsymcount); 653 654 linkmap_add(obj_main); 655 linkmap_add(&obj_rtld); 656 657 /* Link the main program into the list of objects. */ 658 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 659 obj_count++; 660 obj_loads++; 661 662 /* Initialize a fake symbol for resolving undefined weak references. */ 663 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 664 sym_zero.st_shndx = SHN_UNDEF; 665 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 666 667 if (!libmap_disable) 668 libmap_disable = (bool)lm_init(libmap_override); 669 670 dbg("loading LD_PRELOAD libraries"); 671 if (load_preload_objects() == -1) 672 rtld_die(); 673 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 674 675 dbg("loading needed objects"); 676 if (load_needed_objects(obj_main, 0) == -1) 677 rtld_die(); 678 679 /* Make a list of all objects loaded at startup. */ 680 last_interposer = obj_main; 681 TAILQ_FOREACH(obj, &obj_list, next) { 682 if (obj->marker) 683 continue; 684 if (obj->z_interpose && obj != obj_main) { 685 objlist_put_after(&list_main, last_interposer, obj); 686 last_interposer = obj; 687 } else { 688 objlist_push_tail(&list_main, obj); 689 } 690 obj->refcount++; 691 } 692 693 dbg("checking for required versions"); 694 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 695 rtld_die(); 696 697 if (ld_tracing) { /* We're done */ 698 trace_loaded_objects(obj_main); 699 exit(0); 700 } 701 702 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 703 dump_relocations(obj_main); 704 exit (0); 705 } 706 707 /* 708 * Processing tls relocations requires having the tls offsets 709 * initialized. Prepare offsets before starting initial 710 * relocation processing. 711 */ 712 dbg("initializing initial thread local storage offsets"); 713 STAILQ_FOREACH(entry, &list_main, link) { 714 /* 715 * Allocate all the initial objects out of the static TLS 716 * block even if they didn't ask for it. 717 */ 718 allocate_tls_offset(entry->obj); 719 } 720 721 if (relocate_objects(obj_main, 722 ld_bind_now != NULL && *ld_bind_now != '\0', 723 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 724 rtld_die(); 725 726 dbg("doing copy relocations"); 727 if (do_copy_relocations(obj_main) == -1) 728 rtld_die(); 729 730 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 731 dump_relocations(obj_main); 732 exit (0); 733 } 734 735 ifunc_init(aux); 736 737 /* 738 * Setup TLS for main thread. This must be done after the 739 * relocations are processed, since tls initialization section 740 * might be the subject for relocations. 741 */ 742 dbg("initializing initial thread local storage"); 743 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 744 745 dbg("initializing key program variables"); 746 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 747 set_program_var("environ", env); 748 set_program_var("__elf_aux_vector", aux); 749 750 /* Make a list of init functions to call. */ 751 objlist_init(&initlist); 752 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 753 preload_tail, &initlist); 754 755 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 756 757 map_stacks_exec(NULL); 758 759 if (!obj_main->crt_no_init) { 760 /* 761 * Make sure we don't call the main program's init and fini 762 * functions for binaries linked with old crt1 which calls 763 * _init itself. 764 */ 765 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 766 obj_main->preinit_array = obj_main->init_array = 767 obj_main->fini_array = (Elf_Addr)NULL; 768 } 769 770 /* 771 * Execute MD initializers required before we call the objects' 772 * init functions. 773 */ 774 pre_init(); 775 776 wlock_acquire(rtld_bind_lock, &lockstate); 777 778 dbg("resolving ifuncs"); 779 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && 780 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) 781 rtld_die(); 782 783 rtld_exit_ptr = rtld_exit; 784 if (obj_main->crt_no_init) 785 preinit_main(); 786 objlist_call_init(&initlist, &lockstate); 787 _r_debug_postinit(&obj_main->linkmap); 788 objlist_clear(&initlist); 789 dbg("loading filtees"); 790 TAILQ_FOREACH(obj, &obj_list, next) { 791 if (obj->marker) 792 continue; 793 if (ld_loadfltr || obj->z_loadfltr) 794 load_filtees(obj, 0, &lockstate); 795 } 796 797 dbg("enforcing main obj relro"); 798 if (obj_enforce_relro(obj_main) == -1) 799 rtld_die(); 800 801 lock_release(rtld_bind_lock, &lockstate); 802 803 dbg("transferring control to program entry point = %p", obj_main->entry); 804 805 /* Return the exit procedure and the program entry point. */ 806 *exit_proc = rtld_exit_ptr; 807 *objp = obj_main; 808 return (func_ptr_type) obj_main->entry; 809} 810 811void * 812rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 813{ 814 void *ptr; 815 Elf_Addr target; 816 817 ptr = (void *)make_function_pointer(def, obj); 818 target = call_ifunc_resolver(ptr); 819 return ((void *)target); 820} 821 822/* 823 * NB: MIPS uses a private version of this function (_mips_rtld_bind). 824 * Changes to this function should be applied there as well. 825 */ 826Elf_Addr 827_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 828{ 829 const Elf_Rel *rel; 830 const Elf_Sym *def; 831 const Obj_Entry *defobj; 832 Elf_Addr *where; 833 Elf_Addr target; 834 RtldLockState lockstate; 835 836 rlock_acquire(rtld_bind_lock, &lockstate); 837 if (sigsetjmp(lockstate.env, 0) != 0) 838 lock_upgrade(rtld_bind_lock, &lockstate); 839 if (obj->pltrel) 840 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 841 else 842 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 843 844 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 845 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 846 NULL, &lockstate); 847 if (def == NULL) 848 rtld_die(); 849 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 850 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 851 else 852 target = (Elf_Addr)(defobj->relocbase + def->st_value); 853 854 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 855 defobj->strtab + def->st_name, basename(obj->path), 856 (void *)target, basename(defobj->path)); 857 858 /* 859 * Write the new contents for the jmpslot. Note that depending on 860 * architecture, the value which we need to return back to the 861 * lazy binding trampoline may or may not be the target 862 * address. The value returned from reloc_jmpslot() is the value 863 * that the trampoline needs. 864 */ 865 target = reloc_jmpslot(where, target, defobj, obj, rel); 866 lock_release(rtld_bind_lock, &lockstate); 867 return target; 868} 869 870/* 871 * Error reporting function. Use it like printf. If formats the message 872 * into a buffer, and sets things up so that the next call to dlerror() 873 * will return the message. 874 */ 875void 876_rtld_error(const char *fmt, ...) 877{ 878 static char buf[512]; 879 va_list ap; 880 881 va_start(ap, fmt); 882 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 883 error_message = buf; 884 va_end(ap); 885} 886 887/* 888 * Return a dynamically-allocated copy of the current error message, if any. 889 */ 890static char * 891errmsg_save(void) 892{ 893 return error_message == NULL ? NULL : xstrdup(error_message); 894} 895 896/* 897 * Restore the current error message from a copy which was previously saved 898 * by errmsg_save(). The copy is freed. 899 */ 900static void 901errmsg_restore(char *saved_msg) 902{ 903 if (saved_msg == NULL) 904 error_message = NULL; 905 else { 906 _rtld_error("%s", saved_msg); 907 free(saved_msg); 908 } 909} 910 911static const char * 912basename(const char *name) 913{ 914 const char *p = strrchr(name, '/'); 915 return p != NULL ? p + 1 : name; 916} 917 918static struct utsname uts; 919 920static char * 921origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 922 const char *subst, bool may_free) 923{ 924 char *p, *p1, *res, *resp; 925 int subst_len, kw_len, subst_count, old_len, new_len; 926 927 kw_len = strlen(kw); 928 929 /* 930 * First, count the number of the keyword occurrences, to 931 * preallocate the final string. 932 */ 933 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 934 p1 = strstr(p, kw); 935 if (p1 == NULL) 936 break; 937 } 938 939 /* 940 * If the keyword is not found, just return. 941 * 942 * Return non-substituted string if resolution failed. We 943 * cannot do anything more reasonable, the failure mode of the 944 * caller is unresolved library anyway. 945 */ 946 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 947 return (may_free ? real : xstrdup(real)); 948 if (obj != NULL) 949 subst = obj->origin_path; 950 951 /* 952 * There is indeed something to substitute. Calculate the 953 * length of the resulting string, and allocate it. 954 */ 955 subst_len = strlen(subst); 956 old_len = strlen(real); 957 new_len = old_len + (subst_len - kw_len) * subst_count; 958 res = xmalloc(new_len + 1); 959 960 /* 961 * Now, execute the substitution loop. 962 */ 963 for (p = real, resp = res, *resp = '\0';;) { 964 p1 = strstr(p, kw); 965 if (p1 != NULL) { 966 /* Copy the prefix before keyword. */ 967 memcpy(resp, p, p1 - p); 968 resp += p1 - p; 969 /* Keyword replacement. */ 970 memcpy(resp, subst, subst_len); 971 resp += subst_len; 972 *resp = '\0'; 973 p = p1 + kw_len; 974 } else 975 break; 976 } 977 978 /* Copy to the end of string and finish. */ 979 strcat(resp, p); 980 if (may_free) 981 free(real); 982 return (res); 983} 984 985static char * 986origin_subst(Obj_Entry *obj, char *real) 987{ 988 char *res1, *res2, *res3, *res4; 989 990 if (obj == NULL || !trust) 991 return (xstrdup(real)); 992 if (uts.sysname[0] == '\0') { 993 if (uname(&uts) != 0) { 994 _rtld_error("utsname failed: %d", errno); 995 return (NULL); 996 } 997 } 998 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 999 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 1000 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 1001 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 1002 return (res4); 1003} 1004 1005void 1006rtld_die(void) 1007{ 1008 const char *msg = dlerror(); 1009 1010 if (msg == NULL) 1011 msg = "Fatal error"; 1012 rtld_fdputstr(STDERR_FILENO, msg); 1013 rtld_fdputchar(STDERR_FILENO, '\n'); 1014 _exit(1); 1015} 1016 1017/* 1018 * Process a shared object's DYNAMIC section, and save the important 1019 * information in its Obj_Entry structure. 1020 */ 1021static void 1022digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 1023 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 1024{ 1025 const Elf_Dyn *dynp; 1026 Needed_Entry **needed_tail = &obj->needed; 1027 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 1028 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 1029 const Elf_Hashelt *hashtab; 1030 const Elf32_Word *hashval; 1031 Elf32_Word bkt, nmaskwords; 1032 int bloom_size32; 1033 int plttype = DT_REL; 1034 1035 *dyn_rpath = NULL; 1036 *dyn_soname = NULL; 1037 *dyn_runpath = NULL; 1038 1039 obj->bind_now = false; 1040 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 1041 switch (dynp->d_tag) { 1042 1043 case DT_REL: 1044 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 1045 break; 1046 1047 case DT_RELSZ: 1048 obj->relsize = dynp->d_un.d_val; 1049 break; 1050 1051 case DT_RELENT: 1052 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 1053 break; 1054 1055 case DT_JMPREL: 1056 obj->pltrel = (const Elf_Rel *) 1057 (obj->relocbase + dynp->d_un.d_ptr); 1058 break; 1059 1060 case DT_PLTRELSZ: 1061 obj->pltrelsize = dynp->d_un.d_val; 1062 break; 1063 1064 case DT_RELA: 1065 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1066 break; 1067 1068 case DT_RELASZ: 1069 obj->relasize = dynp->d_un.d_val; 1070 break; 1071 1072 case DT_RELAENT: 1073 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1074 break; 1075 1076 case DT_PLTREL: 1077 plttype = dynp->d_un.d_val; 1078 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1079 break; 1080 1081 case DT_SYMTAB: 1082 obj->symtab = (const Elf_Sym *) 1083 (obj->relocbase + dynp->d_un.d_ptr); 1084 break; 1085 1086 case DT_SYMENT: 1087 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1088 break; 1089 1090 case DT_STRTAB: 1091 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1092 break; 1093 1094 case DT_STRSZ: 1095 obj->strsize = dynp->d_un.d_val; 1096 break; 1097 1098 case DT_VERNEED: 1099 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1100 dynp->d_un.d_val); 1101 break; 1102 1103 case DT_VERNEEDNUM: 1104 obj->verneednum = dynp->d_un.d_val; 1105 break; 1106 1107 case DT_VERDEF: 1108 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1109 dynp->d_un.d_val); 1110 break; 1111 1112 case DT_VERDEFNUM: 1113 obj->verdefnum = dynp->d_un.d_val; 1114 break; 1115 1116 case DT_VERSYM: 1117 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1118 dynp->d_un.d_val); 1119 break; 1120 1121 case DT_HASH: 1122 { 1123 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1124 dynp->d_un.d_ptr); 1125 obj->nbuckets = hashtab[0]; 1126 obj->nchains = hashtab[1]; 1127 obj->buckets = hashtab + 2; 1128 obj->chains = obj->buckets + obj->nbuckets; 1129 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1130 obj->buckets != NULL; 1131 } 1132 break; 1133 1134 case DT_GNU_HASH: 1135 { 1136 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1137 dynp->d_un.d_ptr); 1138 obj->nbuckets_gnu = hashtab[0]; 1139 obj->symndx_gnu = hashtab[1]; 1140 nmaskwords = hashtab[2]; 1141 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1142 obj->maskwords_bm_gnu = nmaskwords - 1; 1143 obj->shift2_gnu = hashtab[3]; 1144 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1145 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1146 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1147 obj->symndx_gnu; 1148 /* Number of bitmask words is required to be power of 2 */ 1149 obj->valid_hash_gnu = powerof2(nmaskwords) && 1150 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1151 } 1152 break; 1153 1154 case DT_NEEDED: 1155 if (!obj->rtld) { 1156 Needed_Entry *nep = NEW(Needed_Entry); 1157 nep->name = dynp->d_un.d_val; 1158 nep->obj = NULL; 1159 nep->next = NULL; 1160 1161 *needed_tail = nep; 1162 needed_tail = &nep->next; 1163 } 1164 break; 1165 1166 case DT_FILTER: 1167 if (!obj->rtld) { 1168 Needed_Entry *nep = NEW(Needed_Entry); 1169 nep->name = dynp->d_un.d_val; 1170 nep->obj = NULL; 1171 nep->next = NULL; 1172 1173 *needed_filtees_tail = nep; 1174 needed_filtees_tail = &nep->next; 1175 } 1176 break; 1177 1178 case DT_AUXILIARY: 1179 if (!obj->rtld) { 1180 Needed_Entry *nep = NEW(Needed_Entry); 1181 nep->name = dynp->d_un.d_val; 1182 nep->obj = NULL; 1183 nep->next = NULL; 1184 1185 *needed_aux_filtees_tail = nep; 1186 needed_aux_filtees_tail = &nep->next; 1187 } 1188 break; 1189 1190 case DT_PLTGOT: 1191 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1192 break; 1193 1194 case DT_TEXTREL: 1195 obj->textrel = true; 1196 break; 1197 1198 case DT_SYMBOLIC: 1199 obj->symbolic = true; 1200 break; 1201 1202 case DT_RPATH: 1203 /* 1204 * We have to wait until later to process this, because we 1205 * might not have gotten the address of the string table yet. 1206 */ 1207 *dyn_rpath = dynp; 1208 break; 1209 1210 case DT_SONAME: 1211 *dyn_soname = dynp; 1212 break; 1213 1214 case DT_RUNPATH: 1215 *dyn_runpath = dynp; 1216 break; 1217 1218 case DT_INIT: 1219 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1220 break; 1221 1222 case DT_PREINIT_ARRAY: 1223 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1224 break; 1225 1226 case DT_PREINIT_ARRAYSZ: 1227 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1228 break; 1229 1230 case DT_INIT_ARRAY: 1231 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1232 break; 1233 1234 case DT_INIT_ARRAYSZ: 1235 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1236 break; 1237 1238 case DT_FINI: 1239 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1240 break; 1241 1242 case DT_FINI_ARRAY: 1243 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1244 break; 1245 1246 case DT_FINI_ARRAYSZ: 1247 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1248 break; 1249 1250 /* 1251 * Don't process DT_DEBUG on MIPS as the dynamic section 1252 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1253 */ 1254 1255#ifndef __mips__ 1256 case DT_DEBUG: 1257 if (!early) 1258 dbg("Filling in DT_DEBUG entry"); 1259 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1260 break; 1261#endif 1262 1263 case DT_FLAGS: 1264 if (dynp->d_un.d_val & DF_ORIGIN) 1265 obj->z_origin = true; 1266 if (dynp->d_un.d_val & DF_SYMBOLIC) 1267 obj->symbolic = true; 1268 if (dynp->d_un.d_val & DF_TEXTREL) 1269 obj->textrel = true; 1270 if (dynp->d_un.d_val & DF_BIND_NOW) 1271 obj->bind_now = true; 1272 if (dynp->d_un.d_val & DF_STATIC_TLS) 1273 obj->static_tls = true; 1274 break; 1275#ifdef __mips__ 1276 case DT_MIPS_LOCAL_GOTNO: 1277 obj->local_gotno = dynp->d_un.d_val; 1278 break; 1279 1280 case DT_MIPS_SYMTABNO: 1281 obj->symtabno = dynp->d_un.d_val; 1282 break; 1283 1284 case DT_MIPS_GOTSYM: 1285 obj->gotsym = dynp->d_un.d_val; 1286 break; 1287 1288 case DT_MIPS_RLD_MAP: 1289 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1290 break; 1291#endif 1292 1293#ifdef __powerpc64__ 1294 case DT_PPC64_GLINK: 1295 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1296 break; 1297#endif 1298 1299 case DT_FLAGS_1: 1300 if (dynp->d_un.d_val & DF_1_NOOPEN) 1301 obj->z_noopen = true; 1302 if (dynp->d_un.d_val & DF_1_ORIGIN) 1303 obj->z_origin = true; 1304 if (dynp->d_un.d_val & DF_1_GLOBAL) 1305 obj->z_global = true; 1306 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1307 obj->bind_now = true; 1308 if (dynp->d_un.d_val & DF_1_NODELETE) 1309 obj->z_nodelete = true; 1310 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1311 obj->z_loadfltr = true; 1312 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1313 obj->z_interpose = true; 1314 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1315 obj->z_nodeflib = true; 1316 break; 1317 1318 default: 1319 if (!early) { 1320 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1321 (long)dynp->d_tag); 1322 } 1323 break; 1324 } 1325 } 1326 1327 obj->traced = false; 1328 1329 if (plttype == DT_RELA) { 1330 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1331 obj->pltrel = NULL; 1332 obj->pltrelasize = obj->pltrelsize; 1333 obj->pltrelsize = 0; 1334 } 1335 1336 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1337 if (obj->valid_hash_sysv) 1338 obj->dynsymcount = obj->nchains; 1339 else if (obj->valid_hash_gnu) { 1340 obj->dynsymcount = 0; 1341 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1342 if (obj->buckets_gnu[bkt] == 0) 1343 continue; 1344 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1345 do 1346 obj->dynsymcount++; 1347 while ((*hashval++ & 1u) == 0); 1348 } 1349 obj->dynsymcount += obj->symndx_gnu; 1350 } 1351} 1352 1353static bool 1354obj_resolve_origin(Obj_Entry *obj) 1355{ 1356 1357 if (obj->origin_path != NULL) 1358 return (true); 1359 obj->origin_path = xmalloc(PATH_MAX); 1360 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1361} 1362 1363static bool 1364digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1365 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1366{ 1367 1368 if (obj->z_origin && !obj_resolve_origin(obj)) 1369 return (false); 1370 1371 if (dyn_runpath != NULL) { 1372 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1373 obj->runpath = origin_subst(obj, obj->runpath); 1374 } else if (dyn_rpath != NULL) { 1375 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1376 obj->rpath = origin_subst(obj, obj->rpath); 1377 } 1378 if (dyn_soname != NULL) 1379 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1380 return (true); 1381} 1382 1383static bool 1384digest_dynamic(Obj_Entry *obj, int early) 1385{ 1386 const Elf_Dyn *dyn_rpath; 1387 const Elf_Dyn *dyn_soname; 1388 const Elf_Dyn *dyn_runpath; 1389 1390 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1391 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); 1392} 1393 1394/* 1395 * Process a shared object's program header. This is used only for the 1396 * main program, when the kernel has already loaded the main program 1397 * into memory before calling the dynamic linker. It creates and 1398 * returns an Obj_Entry structure. 1399 */ 1400static Obj_Entry * 1401digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1402{ 1403 Obj_Entry *obj; 1404 const Elf_Phdr *phlimit = phdr + phnum; 1405 const Elf_Phdr *ph; 1406 Elf_Addr note_start, note_end; 1407 int nsegs = 0; 1408 1409 obj = obj_new(); 1410 for (ph = phdr; ph < phlimit; ph++) { 1411 if (ph->p_type != PT_PHDR) 1412 continue; 1413 1414 obj->phdr = phdr; 1415 obj->phsize = ph->p_memsz; 1416 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1417 break; 1418 } 1419 1420 obj->stack_flags = PF_X | PF_R | PF_W; 1421 1422 for (ph = phdr; ph < phlimit; ph++) { 1423 switch (ph->p_type) { 1424 1425 case PT_INTERP: 1426 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1427 break; 1428 1429 case PT_LOAD: 1430 if (nsegs == 0) { /* First load segment */ 1431 obj->vaddrbase = trunc_page(ph->p_vaddr); 1432 obj->mapbase = obj->vaddrbase + obj->relocbase; 1433 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1434 obj->vaddrbase; 1435 } else { /* Last load segment */ 1436 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1437 obj->vaddrbase; 1438 } 1439 nsegs++; 1440 break; 1441 1442 case PT_DYNAMIC: 1443 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1444 break; 1445 1446 case PT_TLS: 1447 obj->tlsindex = 1; 1448 obj->tlssize = ph->p_memsz; 1449 obj->tlsalign = ph->p_align; 1450 obj->tlsinitsize = ph->p_filesz; 1451 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1452 break; 1453 1454 case PT_GNU_STACK: 1455 obj->stack_flags = ph->p_flags; 1456 break; 1457 1458 case PT_GNU_RELRO: 1459 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1460 obj->relro_size = round_page(ph->p_memsz); 1461 break; 1462 1463 case PT_NOTE: 1464 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1465 note_end = note_start + ph->p_filesz; 1466 digest_notes(obj, note_start, note_end); 1467 break; 1468 } 1469 } 1470 if (nsegs < 1) { 1471 _rtld_error("%s: too few PT_LOAD segments", path); 1472 return NULL; 1473 } 1474 1475 obj->entry = entry; 1476 return obj; 1477} 1478 1479void 1480digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1481{ 1482 const Elf_Note *note; 1483 const char *note_name; 1484 uintptr_t p; 1485 1486 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1487 note = (const Elf_Note *)((const char *)(note + 1) + 1488 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1489 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1490 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1491 note->n_descsz != sizeof(int32_t)) 1492 continue; 1493 if (note->n_type != NT_FREEBSD_ABI_TAG && 1494 note->n_type != NT_FREEBSD_NOINIT_TAG) 1495 continue; 1496 note_name = (const char *)(note + 1); 1497 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1498 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1499 continue; 1500 switch (note->n_type) { 1501 case NT_FREEBSD_ABI_TAG: 1502 /* FreeBSD osrel note */ 1503 p = (uintptr_t)(note + 1); 1504 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1505 obj->osrel = *(const int32_t *)(p); 1506 dbg("note osrel %d", obj->osrel); 1507 break; 1508 case NT_FREEBSD_NOINIT_TAG: 1509 /* FreeBSD 'crt does not call init' note */ 1510 obj->crt_no_init = true; 1511 dbg("note crt_no_init"); 1512 break; 1513 } 1514 } 1515} 1516 1517static Obj_Entry * 1518dlcheck(void *handle) 1519{ 1520 Obj_Entry *obj; 1521 1522 TAILQ_FOREACH(obj, &obj_list, next) { 1523 if (obj == (Obj_Entry *) handle) 1524 break; 1525 } 1526 1527 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1528 _rtld_error("Invalid shared object handle %p", handle); 1529 return NULL; 1530 } 1531 return obj; 1532} 1533 1534/* 1535 * If the given object is already in the donelist, return true. Otherwise 1536 * add the object to the list and return false. 1537 */ 1538static bool 1539donelist_check(DoneList *dlp, const Obj_Entry *obj) 1540{ 1541 unsigned int i; 1542 1543 for (i = 0; i < dlp->num_used; i++) 1544 if (dlp->objs[i] == obj) 1545 return true; 1546 /* 1547 * Our donelist allocation should always be sufficient. But if 1548 * our threads locking isn't working properly, more shared objects 1549 * could have been loaded since we allocated the list. That should 1550 * never happen, but we'll handle it properly just in case it does. 1551 */ 1552 if (dlp->num_used < dlp->num_alloc) 1553 dlp->objs[dlp->num_used++] = obj; 1554 return false; 1555} 1556 1557/* 1558 * Hash function for symbol table lookup. Don't even think about changing 1559 * this. It is specified by the System V ABI. 1560 */ 1561unsigned long 1562elf_hash(const char *name) 1563{ 1564 const unsigned char *p = (const unsigned char *) name; 1565 unsigned long h = 0; 1566 unsigned long g; 1567 1568 while (*p != '\0') { 1569 h = (h << 4) + *p++; 1570 if ((g = h & 0xf0000000) != 0) 1571 h ^= g >> 24; 1572 h &= ~g; 1573 } 1574 return h; 1575} 1576 1577/* 1578 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1579 * unsigned in case it's implemented with a wider type. 1580 */ 1581static uint32_t 1582gnu_hash(const char *s) 1583{ 1584 uint32_t h; 1585 unsigned char c; 1586 1587 h = 5381; 1588 for (c = *s; c != '\0'; c = *++s) 1589 h = h * 33 + c; 1590 return (h & 0xffffffff); 1591} 1592 1593 1594/* 1595 * Find the library with the given name, and return its full pathname. 1596 * The returned string is dynamically allocated. Generates an error 1597 * message and returns NULL if the library cannot be found. 1598 * 1599 * If the second argument is non-NULL, then it refers to an already- 1600 * loaded shared object, whose library search path will be searched. 1601 * 1602 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1603 * descriptor (which is close-on-exec) will be passed out via the third 1604 * argument. 1605 * 1606 * The search order is: 1607 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1608 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1609 * LD_LIBRARY_PATH 1610 * DT_RUNPATH in the referencing file 1611 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1612 * from list) 1613 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1614 * 1615 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1616 */ 1617static char * 1618find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1619{ 1620 char *name, *pathname, *refobj_path; 1621 bool nodeflib, objgiven; 1622 1623 objgiven = refobj != NULL; 1624 1625 if (libmap_disable || !objgiven || 1626 (name = lm_find(refobj->path, xname)) == NULL) 1627 name = (char *)xname; 1628 1629 if (strchr(name, '/') != NULL) { /* Hard coded pathname */ 1630 if (name[0] != '/' && !trust) { 1631 _rtld_error("Absolute pathname required " 1632 "for shared object \"%s\"", name); 1633 return (NULL); 1634 } 1635 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1636 __DECONST(char *, name))); 1637 } 1638 1639 dbg(" Searching for \"%s\"", name); 1640 refobj_path = objgiven ? refobj->path : NULL; 1641 1642 /* 1643 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1644 * back to pre-conforming behaviour if user requested so with 1645 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1646 * nodeflib. 1647 */ 1648 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1649 pathname = search_library_path(name, ld_library_path, 1650 refobj_path, fdp); 1651 if (pathname != NULL) 1652 return (pathname); 1653 if (refobj != NULL) { 1654 pathname = search_library_path(name, refobj->rpath, 1655 refobj_path, fdp); 1656 if (pathname != NULL) 1657 return (pathname); 1658 } 1659 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1660 if (pathname != NULL) 1661 return (pathname); 1662 pathname = search_library_path(name, gethints(false), 1663 refobj_path, fdp); 1664 if (pathname != NULL) 1665 return (pathname); 1666 pathname = search_library_path(name, ld_standard_library_path, 1667 refobj_path, fdp); 1668 if (pathname != NULL) 1669 return (pathname); 1670 } else { 1671 nodeflib = objgiven ? refobj->z_nodeflib : false; 1672 if (objgiven) { 1673 pathname = search_library_path(name, refobj->rpath, 1674 refobj->path, fdp); 1675 if (pathname != NULL) 1676 return (pathname); 1677 } 1678 if (objgiven && refobj->runpath == NULL && refobj != obj_main) { 1679 pathname = search_library_path(name, obj_main->rpath, 1680 refobj_path, fdp); 1681 if (pathname != NULL) 1682 return (pathname); 1683 } 1684 pathname = search_library_path(name, ld_library_path, 1685 refobj_path, fdp); 1686 if (pathname != NULL) 1687 return (pathname); 1688 if (objgiven) { 1689 pathname = search_library_path(name, refobj->runpath, 1690 refobj_path, fdp); 1691 if (pathname != NULL) 1692 return (pathname); 1693 } 1694 pathname = search_library_pathfds(name, ld_library_dirs, fdp); 1695 if (pathname != NULL) 1696 return (pathname); 1697 pathname = search_library_path(name, gethints(nodeflib), 1698 refobj_path, fdp); 1699 if (pathname != NULL) 1700 return (pathname); 1701 if (objgiven && !nodeflib) { 1702 pathname = search_library_path(name, 1703 ld_standard_library_path, refobj_path, fdp); 1704 if (pathname != NULL) 1705 return (pathname); 1706 } 1707 } 1708 1709 if (objgiven && refobj->path != NULL) { 1710 _rtld_error("Shared object \"%s\" not found, " 1711 "required by \"%s\"", name, basename(refobj->path)); 1712 } else { 1713 _rtld_error("Shared object \"%s\" not found", name); 1714 } 1715 return (NULL); 1716} 1717 1718/* 1719 * Given a symbol number in a referencing object, find the corresponding 1720 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1721 * no definition was found. Returns a pointer to the Obj_Entry of the 1722 * defining object via the reference parameter DEFOBJ_OUT. 1723 */ 1724const Elf_Sym * 1725find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1726 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1727 RtldLockState *lockstate) 1728{ 1729 const Elf_Sym *ref; 1730 const Elf_Sym *def; 1731 const Obj_Entry *defobj; 1732 const Ver_Entry *ve; 1733 SymLook req; 1734 const char *name; 1735 int res; 1736 1737 /* 1738 * If we have already found this symbol, get the information from 1739 * the cache. 1740 */ 1741 if (symnum >= refobj->dynsymcount) 1742 return NULL; /* Bad object */ 1743 if (cache != NULL && cache[symnum].sym != NULL) { 1744 *defobj_out = cache[symnum].obj; 1745 return cache[symnum].sym; 1746 } 1747 1748 ref = refobj->symtab + symnum; 1749 name = refobj->strtab + ref->st_name; 1750 def = NULL; 1751 defobj = NULL; 1752 ve = NULL; 1753 1754 /* 1755 * We don't have to do a full scale lookup if the symbol is local. 1756 * We know it will bind to the instance in this load module; to 1757 * which we already have a pointer (ie ref). By not doing a lookup, 1758 * we not only improve performance, but it also avoids unresolvable 1759 * symbols when local symbols are not in the hash table. This has 1760 * been seen with the ia64 toolchain. 1761 */ 1762 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1763 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1764 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1765 symnum); 1766 } 1767 symlook_init(&req, name); 1768 req.flags = flags; 1769 ve = req.ventry = fetch_ventry(refobj, symnum); 1770 req.lockstate = lockstate; 1771 res = symlook_default(&req, refobj); 1772 if (res == 0) { 1773 def = req.sym_out; 1774 defobj = req.defobj_out; 1775 } 1776 } else { 1777 def = ref; 1778 defobj = refobj; 1779 } 1780 1781 /* 1782 * If we found no definition and the reference is weak, treat the 1783 * symbol as having the value zero. 1784 */ 1785 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1786 def = &sym_zero; 1787 defobj = obj_main; 1788 } 1789 1790 if (def != NULL) { 1791 *defobj_out = defobj; 1792 /* Record the information in the cache to avoid subsequent lookups. */ 1793 if (cache != NULL) { 1794 cache[symnum].sym = def; 1795 cache[symnum].obj = defobj; 1796 } 1797 } else { 1798 if (refobj != &obj_rtld) 1799 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1800 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1801 } 1802 return def; 1803} 1804 1805/* 1806 * Return the search path from the ldconfig hints file, reading it if 1807 * necessary. If nostdlib is true, then the default search paths are 1808 * not added to result. 1809 * 1810 * Returns NULL if there are problems with the hints file, 1811 * or if the search path there is empty. 1812 */ 1813static const char * 1814gethints(bool nostdlib) 1815{ 1816 static char *hints, *filtered_path; 1817 static struct elfhints_hdr hdr; 1818 struct fill_search_info_args sargs, hargs; 1819 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1820 struct dl_serpath *SLPpath, *hintpath; 1821 char *p; 1822 struct stat hint_stat; 1823 unsigned int SLPndx, hintndx, fndx, fcount; 1824 int fd; 1825 size_t flen; 1826 uint32_t dl; 1827 bool skip; 1828 1829 /* First call, read the hints file */ 1830 if (hints == NULL) { 1831 /* Keep from trying again in case the hints file is bad. */ 1832 hints = ""; 1833 1834 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1835 return (NULL); 1836 1837 /* 1838 * Check of hdr.dirlistlen value against type limit 1839 * intends to pacify static analyzers. Further 1840 * paranoia leads to checks that dirlist is fully 1841 * contained in the file range. 1842 */ 1843 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1844 hdr.magic != ELFHINTS_MAGIC || 1845 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1846 fstat(fd, &hint_stat) == -1) { 1847cleanup1: 1848 close(fd); 1849 hdr.dirlistlen = 0; 1850 return (NULL); 1851 } 1852 dl = hdr.strtab; 1853 if (dl + hdr.dirlist < dl) 1854 goto cleanup1; 1855 dl += hdr.dirlist; 1856 if (dl + hdr.dirlistlen < dl) 1857 goto cleanup1; 1858 dl += hdr.dirlistlen; 1859 if (dl > hint_stat.st_size) 1860 goto cleanup1; 1861 p = xmalloc(hdr.dirlistlen + 1); 1862 if (pread(fd, p, hdr.dirlistlen + 1, 1863 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 || 1864 p[hdr.dirlistlen] != '\0') { 1865 free(p); 1866 goto cleanup1; 1867 } 1868 hints = p; 1869 close(fd); 1870 } 1871 1872 /* 1873 * If caller agreed to receive list which includes the default 1874 * paths, we are done. Otherwise, if we still did not 1875 * calculated filtered result, do it now. 1876 */ 1877 if (!nostdlib) 1878 return (hints[0] != '\0' ? hints : NULL); 1879 if (filtered_path != NULL) 1880 goto filt_ret; 1881 1882 /* 1883 * Obtain the list of all configured search paths, and the 1884 * list of the default paths. 1885 * 1886 * First estimate the size of the results. 1887 */ 1888 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1889 smeta.dls_cnt = 0; 1890 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1891 hmeta.dls_cnt = 0; 1892 1893 sargs.request = RTLD_DI_SERINFOSIZE; 1894 sargs.serinfo = &smeta; 1895 hargs.request = RTLD_DI_SERINFOSIZE; 1896 hargs.serinfo = &hmeta; 1897 1898 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1899 &sargs); 1900 path_enumerate(hints, fill_search_info, NULL, &hargs); 1901 1902 SLPinfo = xmalloc(smeta.dls_size); 1903 hintinfo = xmalloc(hmeta.dls_size); 1904 1905 /* 1906 * Next fetch both sets of paths. 1907 */ 1908 sargs.request = RTLD_DI_SERINFO; 1909 sargs.serinfo = SLPinfo; 1910 sargs.serpath = &SLPinfo->dls_serpath[0]; 1911 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1912 1913 hargs.request = RTLD_DI_SERINFO; 1914 hargs.serinfo = hintinfo; 1915 hargs.serpath = &hintinfo->dls_serpath[0]; 1916 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1917 1918 path_enumerate(ld_standard_library_path, fill_search_info, NULL, 1919 &sargs); 1920 path_enumerate(hints, fill_search_info, NULL, &hargs); 1921 1922 /* 1923 * Now calculate the difference between two sets, by excluding 1924 * standard paths from the full set. 1925 */ 1926 fndx = 0; 1927 fcount = 0; 1928 filtered_path = xmalloc(hdr.dirlistlen + 1); 1929 hintpath = &hintinfo->dls_serpath[0]; 1930 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1931 skip = false; 1932 SLPpath = &SLPinfo->dls_serpath[0]; 1933 /* 1934 * Check each standard path against current. 1935 */ 1936 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1937 /* matched, skip the path */ 1938 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1939 skip = true; 1940 break; 1941 } 1942 } 1943 if (skip) 1944 continue; 1945 /* 1946 * Not matched against any standard path, add the path 1947 * to result. Separate consequtive paths with ':'. 1948 */ 1949 if (fcount > 0) { 1950 filtered_path[fndx] = ':'; 1951 fndx++; 1952 } 1953 fcount++; 1954 flen = strlen(hintpath->dls_name); 1955 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1956 fndx += flen; 1957 } 1958 filtered_path[fndx] = '\0'; 1959 1960 free(SLPinfo); 1961 free(hintinfo); 1962 1963filt_ret: 1964 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1965} 1966 1967static void 1968init_dag(Obj_Entry *root) 1969{ 1970 const Needed_Entry *needed; 1971 const Objlist_Entry *elm; 1972 DoneList donelist; 1973 1974 if (root->dag_inited) 1975 return; 1976 donelist_init(&donelist); 1977 1978 /* Root object belongs to own DAG. */ 1979 objlist_push_tail(&root->dldags, root); 1980 objlist_push_tail(&root->dagmembers, root); 1981 donelist_check(&donelist, root); 1982 1983 /* 1984 * Add dependencies of root object to DAG in breadth order 1985 * by exploiting the fact that each new object get added 1986 * to the tail of the dagmembers list. 1987 */ 1988 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1989 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1990 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1991 continue; 1992 objlist_push_tail(&needed->obj->dldags, root); 1993 objlist_push_tail(&root->dagmembers, needed->obj); 1994 } 1995 } 1996 root->dag_inited = true; 1997} 1998 1999static void 2000init_marker(Obj_Entry *marker) 2001{ 2002 2003 bzero(marker, sizeof(*marker)); 2004 marker->marker = true; 2005} 2006 2007Obj_Entry * 2008globallist_curr(const Obj_Entry *obj) 2009{ 2010 2011 for (;;) { 2012 if (obj == NULL) 2013 return (NULL); 2014 if (!obj->marker) 2015 return (__DECONST(Obj_Entry *, obj)); 2016 obj = TAILQ_PREV(obj, obj_entry_q, next); 2017 } 2018} 2019 2020Obj_Entry * 2021globallist_next(const Obj_Entry *obj) 2022{ 2023 2024 for (;;) { 2025 obj = TAILQ_NEXT(obj, next); 2026 if (obj == NULL) 2027 return (NULL); 2028 if (!obj->marker) 2029 return (__DECONST(Obj_Entry *, obj)); 2030 } 2031} 2032 2033/* Prevent the object from being unmapped while the bind lock is dropped. */ 2034static void 2035hold_object(Obj_Entry *obj) 2036{ 2037 2038 obj->holdcount++; 2039} 2040 2041static void 2042unhold_object(Obj_Entry *obj) 2043{ 2044 2045 assert(obj->holdcount > 0); 2046 if (--obj->holdcount == 0 && obj->unholdfree) 2047 release_object(obj); 2048} 2049 2050static void 2051process_z(Obj_Entry *root) 2052{ 2053 const Objlist_Entry *elm; 2054 Obj_Entry *obj; 2055 2056 /* 2057 * Walk over object DAG and process every dependent object 2058 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 2059 * to grow their own DAG. 2060 * 2061 * For DF_1_GLOBAL, DAG is required for symbol lookups in 2062 * symlook_global() to work. 2063 * 2064 * For DF_1_NODELETE, the DAG should have its reference upped. 2065 */ 2066 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2067 obj = elm->obj; 2068 if (obj == NULL) 2069 continue; 2070 if (obj->z_nodelete && !obj->ref_nodel) { 2071 dbg("obj %s -z nodelete", obj->path); 2072 init_dag(obj); 2073 ref_dag(obj); 2074 obj->ref_nodel = true; 2075 } 2076 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 2077 dbg("obj %s -z global", obj->path); 2078 objlist_push_tail(&list_global, obj); 2079 init_dag(obj); 2080 } 2081 } 2082} 2083/* 2084 * Initialize the dynamic linker. The argument is the address at which 2085 * the dynamic linker has been mapped into memory. The primary task of 2086 * this function is to relocate the dynamic linker. 2087 */ 2088static void 2089init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 2090{ 2091 Obj_Entry objtmp; /* Temporary rtld object */ 2092 const Elf_Ehdr *ehdr; 2093 const Elf_Dyn *dyn_rpath; 2094 const Elf_Dyn *dyn_soname; 2095 const Elf_Dyn *dyn_runpath; 2096 2097#ifdef RTLD_INIT_PAGESIZES_EARLY 2098 /* The page size is required by the dynamic memory allocator. */ 2099 init_pagesizes(aux_info); 2100#endif 2101 2102 /* 2103 * Conjure up an Obj_Entry structure for the dynamic linker. 2104 * 2105 * The "path" member can't be initialized yet because string constants 2106 * cannot yet be accessed. Below we will set it correctly. 2107 */ 2108 memset(&objtmp, 0, sizeof(objtmp)); 2109 objtmp.path = NULL; 2110 objtmp.rtld = true; 2111 objtmp.mapbase = mapbase; 2112#ifdef PIC 2113 objtmp.relocbase = mapbase; 2114#endif 2115 2116 objtmp.dynamic = rtld_dynamic(&objtmp); 2117 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 2118 assert(objtmp.needed == NULL); 2119#if !defined(__mips__) 2120 /* MIPS has a bogus DT_TEXTREL. */ 2121 assert(!objtmp.textrel); 2122#endif 2123 /* 2124 * Temporarily put the dynamic linker entry into the object list, so 2125 * that symbols can be found. 2126 */ 2127 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 2128 2129 ehdr = (Elf_Ehdr *)mapbase; 2130 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 2131 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 2132 2133 /* Initialize the object list. */ 2134 TAILQ_INIT(&obj_list); 2135 2136 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 2137 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 2138 2139#ifndef RTLD_INIT_PAGESIZES_EARLY 2140 /* The page size is required by the dynamic memory allocator. */ 2141 init_pagesizes(aux_info); 2142#endif 2143 2144 if (aux_info[AT_OSRELDATE] != NULL) 2145 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 2146 2147 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 2148 2149 /* Replace the path with a dynamically allocated copy. */ 2150 obj_rtld.path = xstrdup(ld_path_rtld); 2151 2152 r_debug.r_brk = r_debug_state; 2153 r_debug.r_state = RT_CONSISTENT; 2154} 2155 2156/* 2157 * Retrieve the array of supported page sizes. The kernel provides the page 2158 * sizes in increasing order. 2159 */ 2160static void 2161init_pagesizes(Elf_Auxinfo **aux_info) 2162{ 2163 static size_t psa[MAXPAGESIZES]; 2164 int mib[2]; 2165 size_t len, size; 2166 2167 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 2168 NULL) { 2169 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 2170 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2171 } else { 2172 len = 2; 2173 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2174 size = sizeof(psa); 2175 else { 2176 /* As a fallback, retrieve the base page size. */ 2177 size = sizeof(psa[0]); 2178 if (aux_info[AT_PAGESZ] != NULL) { 2179 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2180 goto psa_filled; 2181 } else { 2182 mib[0] = CTL_HW; 2183 mib[1] = HW_PAGESIZE; 2184 len = 2; 2185 } 2186 } 2187 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2188 _rtld_error("sysctl for hw.pagesize(s) failed"); 2189 rtld_die(); 2190 } 2191psa_filled: 2192 pagesizes = psa; 2193 } 2194 npagesizes = size / sizeof(pagesizes[0]); 2195 /* Discard any invalid entries at the end of the array. */ 2196 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2197 npagesizes--; 2198} 2199 2200/* 2201 * Add the init functions from a needed object list (and its recursive 2202 * needed objects) to "list". This is not used directly; it is a helper 2203 * function for initlist_add_objects(). The write lock must be held 2204 * when this function is called. 2205 */ 2206static void 2207initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2208{ 2209 /* Recursively process the successor needed objects. */ 2210 if (needed->next != NULL) 2211 initlist_add_neededs(needed->next, list); 2212 2213 /* Process the current needed object. */ 2214 if (needed->obj != NULL) 2215 initlist_add_objects(needed->obj, needed->obj, list); 2216} 2217 2218/* 2219 * Scan all of the DAGs rooted in the range of objects from "obj" to 2220 * "tail" and add their init functions to "list". This recurses over 2221 * the DAGs and ensure the proper init ordering such that each object's 2222 * needed libraries are initialized before the object itself. At the 2223 * same time, this function adds the objects to the global finalization 2224 * list "list_fini" in the opposite order. The write lock must be 2225 * held when this function is called. 2226 */ 2227static void 2228initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2229{ 2230 Obj_Entry *nobj; 2231 2232 if (obj->init_scanned || obj->init_done) 2233 return; 2234 obj->init_scanned = true; 2235 2236 /* Recursively process the successor objects. */ 2237 nobj = globallist_next(obj); 2238 if (nobj != NULL && obj != tail) 2239 initlist_add_objects(nobj, tail, list); 2240 2241 /* Recursively process the needed objects. */ 2242 if (obj->needed != NULL) 2243 initlist_add_neededs(obj->needed, list); 2244 if (obj->needed_filtees != NULL) 2245 initlist_add_neededs(obj->needed_filtees, list); 2246 if (obj->needed_aux_filtees != NULL) 2247 initlist_add_neededs(obj->needed_aux_filtees, list); 2248 2249 /* Add the object to the init list. */ 2250 objlist_push_tail(list, obj); 2251 2252 /* Add the object to the global fini list in the reverse order. */ 2253 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2254 && !obj->on_fini_list) { 2255 objlist_push_head(&list_fini, obj); 2256 obj->on_fini_list = true; 2257 } 2258} 2259 2260#ifndef FPTR_TARGET 2261#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2262#endif 2263 2264static void 2265free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) 2266{ 2267 Needed_Entry *needed, *needed1; 2268 2269 for (needed = n; needed != NULL; needed = needed->next) { 2270 if (needed->obj != NULL) { 2271 dlclose_locked(needed->obj, lockstate); 2272 needed->obj = NULL; 2273 } 2274 } 2275 for (needed = n; needed != NULL; needed = needed1) { 2276 needed1 = needed->next; 2277 free(needed); 2278 } 2279} 2280 2281static void 2282unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) 2283{ 2284 2285 free_needed_filtees(obj->needed_filtees, lockstate); 2286 obj->needed_filtees = NULL; 2287 free_needed_filtees(obj->needed_aux_filtees, lockstate); 2288 obj->needed_aux_filtees = NULL; 2289 obj->filtees_loaded = false; 2290} 2291 2292static void 2293load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2294 RtldLockState *lockstate) 2295{ 2296 2297 for (; needed != NULL; needed = needed->next) { 2298 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2299 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2300 RTLD_LOCAL, lockstate); 2301 } 2302} 2303 2304static void 2305load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2306{ 2307 2308 lock_restart_for_upgrade(lockstate); 2309 if (!obj->filtees_loaded) { 2310 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2311 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2312 obj->filtees_loaded = true; 2313 } 2314} 2315 2316static int 2317process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2318{ 2319 Obj_Entry *obj1; 2320 2321 for (; needed != NULL; needed = needed->next) { 2322 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2323 flags & ~RTLD_LO_NOLOAD); 2324 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2325 return (-1); 2326 } 2327 return (0); 2328} 2329 2330/* 2331 * Given a shared object, traverse its list of needed objects, and load 2332 * each of them. Returns 0 on success. Generates an error message and 2333 * returns -1 on failure. 2334 */ 2335static int 2336load_needed_objects(Obj_Entry *first, int flags) 2337{ 2338 Obj_Entry *obj; 2339 2340 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2341 if (obj->marker) 2342 continue; 2343 if (process_needed(obj, obj->needed, flags) == -1) 2344 return (-1); 2345 } 2346 return (0); 2347} 2348 2349static int 2350load_preload_objects(void) 2351{ 2352 char *p = ld_preload; 2353 Obj_Entry *obj; 2354 static const char delim[] = " \t:;"; 2355 2356 if (p == NULL) 2357 return 0; 2358 2359 p += strspn(p, delim); 2360 while (*p != '\0') { 2361 size_t len = strcspn(p, delim); 2362 char savech; 2363 2364 savech = p[len]; 2365 p[len] = '\0'; 2366 obj = load_object(p, -1, NULL, 0); 2367 if (obj == NULL) 2368 return -1; /* XXX - cleanup */ 2369 obj->z_interpose = true; 2370 p[len] = savech; 2371 p += len; 2372 p += strspn(p, delim); 2373 } 2374 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2375 return 0; 2376} 2377 2378static const char * 2379printable_path(const char *path) 2380{ 2381 2382 return (path == NULL ? "<unknown>" : path); 2383} 2384 2385/* 2386 * Load a shared object into memory, if it is not already loaded. The 2387 * object may be specified by name or by user-supplied file descriptor 2388 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2389 * duplicate is. 2390 * 2391 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2392 * on failure. 2393 */ 2394static Obj_Entry * 2395load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2396{ 2397 Obj_Entry *obj; 2398 int fd; 2399 struct stat sb; 2400 char *path; 2401 2402 fd = -1; 2403 if (name != NULL) { 2404 TAILQ_FOREACH(obj, &obj_list, next) { 2405 if (obj->marker || obj->doomed) 2406 continue; 2407 if (object_match_name(obj, name)) 2408 return (obj); 2409 } 2410 2411 path = find_library(name, refobj, &fd); 2412 if (path == NULL) 2413 return (NULL); 2414 } else 2415 path = NULL; 2416 2417 if (fd >= 0) { 2418 /* 2419 * search_library_pathfds() opens a fresh file descriptor for the 2420 * library, so there is no need to dup(). 2421 */ 2422 } else if (fd_u == -1) { 2423 /* 2424 * If we didn't find a match by pathname, or the name is not 2425 * supplied, open the file and check again by device and inode. 2426 * This avoids false mismatches caused by multiple links or ".." 2427 * in pathnames. 2428 * 2429 * To avoid a race, we open the file and use fstat() rather than 2430 * using stat(). 2431 */ 2432 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2433 _rtld_error("Cannot open \"%s\"", path); 2434 free(path); 2435 return (NULL); 2436 } 2437 } else { 2438 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2439 if (fd == -1) { 2440 _rtld_error("Cannot dup fd"); 2441 free(path); 2442 return (NULL); 2443 } 2444 } 2445 if (fstat(fd, &sb) == -1) { 2446 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2447 close(fd); 2448 free(path); 2449 return NULL; 2450 } 2451 TAILQ_FOREACH(obj, &obj_list, next) { 2452 if (obj->marker || obj->doomed) 2453 continue; 2454 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2455 break; 2456 } 2457 if (obj != NULL && name != NULL) { 2458 object_add_name(obj, name); 2459 free(path); 2460 close(fd); 2461 return obj; 2462 } 2463 if (flags & RTLD_LO_NOLOAD) { 2464 free(path); 2465 close(fd); 2466 return (NULL); 2467 } 2468 2469 /* First use of this object, so we must map it in */ 2470 obj = do_load_object(fd, name, path, &sb, flags); 2471 if (obj == NULL) 2472 free(path); 2473 close(fd); 2474 2475 return obj; 2476} 2477 2478static Obj_Entry * 2479do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2480 int flags) 2481{ 2482 Obj_Entry *obj; 2483 struct statfs fs; 2484 2485 /* 2486 * but first, make sure that environment variables haven't been 2487 * used to circumvent the noexec flag on a filesystem. 2488 */ 2489 if (dangerous_ld_env) { 2490 if (fstatfs(fd, &fs) != 0) { 2491 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2492 return NULL; 2493 } 2494 if (fs.f_flags & MNT_NOEXEC) { 2495 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2496 return NULL; 2497 } 2498 } 2499 dbg("loading \"%s\"", printable_path(path)); 2500 obj = map_object(fd, printable_path(path), sbp); 2501 if (obj == NULL) 2502 return NULL; 2503 2504 /* 2505 * If DT_SONAME is present in the object, digest_dynamic2 already 2506 * added it to the object names. 2507 */ 2508 if (name != NULL) 2509 object_add_name(obj, name); 2510 obj->path = path; 2511 if (!digest_dynamic(obj, 0)) 2512 goto errp; 2513 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2514 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2515 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2516 RTLD_LO_DLOPEN) { 2517 dbg("refusing to load non-loadable \"%s\"", obj->path); 2518 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2519 goto errp; 2520 } 2521 2522 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2523 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2524 obj_count++; 2525 obj_loads++; 2526 linkmap_add(obj); /* for GDB & dlinfo() */ 2527 max_stack_flags |= obj->stack_flags; 2528 2529 dbg(" %p .. %p: %s", obj->mapbase, 2530 obj->mapbase + obj->mapsize - 1, obj->path); 2531 if (obj->textrel) 2532 dbg(" WARNING: %s has impure text", obj->path); 2533 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2534 obj->path); 2535 2536 return (obj); 2537 2538errp: 2539 munmap(obj->mapbase, obj->mapsize); 2540 obj_free(obj); 2541 return (NULL); 2542} 2543 2544static Obj_Entry * 2545obj_from_addr(const void *addr) 2546{ 2547 Obj_Entry *obj; 2548 2549 TAILQ_FOREACH(obj, &obj_list, next) { 2550 if (obj->marker) 2551 continue; 2552 if (addr < (void *) obj->mapbase) 2553 continue; 2554 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2555 return obj; 2556 } 2557 return NULL; 2558} 2559 2560static void 2561preinit_main(void) 2562{ 2563 Elf_Addr *preinit_addr; 2564 int index; 2565 2566 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2567 if (preinit_addr == NULL) 2568 return; 2569 2570 for (index = 0; index < obj_main->preinit_array_num; index++) { 2571 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2572 dbg("calling preinit function for %s at %p", obj_main->path, 2573 (void *)preinit_addr[index]); 2574 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2575 0, 0, obj_main->path); 2576 call_init_pointer(obj_main, preinit_addr[index]); 2577 } 2578 } 2579} 2580 2581/* 2582 * Call the finalization functions for each of the objects in "list" 2583 * belonging to the DAG of "root" and referenced once. If NULL "root" 2584 * is specified, every finalization function will be called regardless 2585 * of the reference count and the list elements won't be freed. All of 2586 * the objects are expected to have non-NULL fini functions. 2587 */ 2588static void 2589objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2590{ 2591 Objlist_Entry *elm; 2592 char *saved_msg; 2593 Elf_Addr *fini_addr; 2594 int index; 2595 2596 assert(root == NULL || root->refcount == 1); 2597 2598 if (root != NULL) 2599 root->doomed = true; 2600 2601 /* 2602 * Preserve the current error message since a fini function might 2603 * call into the dynamic linker and overwrite it. 2604 */ 2605 saved_msg = errmsg_save(); 2606 do { 2607 STAILQ_FOREACH(elm, list, link) { 2608 if (root != NULL && (elm->obj->refcount != 1 || 2609 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2610 continue; 2611 /* Remove object from fini list to prevent recursive invocation. */ 2612 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2613 /* Ensure that new references cannot be acquired. */ 2614 elm->obj->doomed = true; 2615 2616 hold_object(elm->obj); 2617 lock_release(rtld_bind_lock, lockstate); 2618 /* 2619 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2620 * When this happens, DT_FINI_ARRAY is processed first. 2621 */ 2622 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2623 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2624 for (index = elm->obj->fini_array_num - 1; index >= 0; 2625 index--) { 2626 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2627 dbg("calling fini function for %s at %p", 2628 elm->obj->path, (void *)fini_addr[index]); 2629 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2630 (void *)fini_addr[index], 0, 0, elm->obj->path); 2631 call_initfini_pointer(elm->obj, fini_addr[index]); 2632 } 2633 } 2634 } 2635 if (elm->obj->fini != (Elf_Addr)NULL) { 2636 dbg("calling fini function for %s at %p", elm->obj->path, 2637 (void *)elm->obj->fini); 2638 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2639 0, 0, elm->obj->path); 2640 call_initfini_pointer(elm->obj, elm->obj->fini); 2641 } 2642 wlock_acquire(rtld_bind_lock, lockstate); 2643 unhold_object(elm->obj); 2644 /* No need to free anything if process is going down. */ 2645 if (root != NULL) 2646 free(elm); 2647 /* 2648 * We must restart the list traversal after every fini call 2649 * because a dlclose() call from the fini function or from 2650 * another thread might have modified the reference counts. 2651 */ 2652 break; 2653 } 2654 } while (elm != NULL); 2655 errmsg_restore(saved_msg); 2656} 2657 2658/* 2659 * Call the initialization functions for each of the objects in 2660 * "list". All of the objects are expected to have non-NULL init 2661 * functions. 2662 */ 2663static void 2664objlist_call_init(Objlist *list, RtldLockState *lockstate) 2665{ 2666 Objlist_Entry *elm; 2667 Obj_Entry *obj; 2668 char *saved_msg; 2669 Elf_Addr *init_addr; 2670 void (*reg)(void (*)(void)); 2671 int index; 2672 2673 /* 2674 * Clean init_scanned flag so that objects can be rechecked and 2675 * possibly initialized earlier if any of vectors called below 2676 * cause the change by using dlopen. 2677 */ 2678 TAILQ_FOREACH(obj, &obj_list, next) { 2679 if (obj->marker) 2680 continue; 2681 obj->init_scanned = false; 2682 } 2683 2684 /* 2685 * Preserve the current error message since an init function might 2686 * call into the dynamic linker and overwrite it. 2687 */ 2688 saved_msg = errmsg_save(); 2689 STAILQ_FOREACH(elm, list, link) { 2690 if (elm->obj->init_done) /* Initialized early. */ 2691 continue; 2692 /* 2693 * Race: other thread might try to use this object before current 2694 * one completes the initialization. Not much can be done here 2695 * without better locking. 2696 */ 2697 elm->obj->init_done = true; 2698 hold_object(elm->obj); 2699 reg = NULL; 2700 if (elm->obj == obj_main && obj_main->crt_no_init) { 2701 reg = (void (*)(void (*)(void)))get_program_var_addr( 2702 "__libc_atexit", lockstate); 2703 } 2704 lock_release(rtld_bind_lock, lockstate); 2705 if (reg != NULL) { 2706 reg(rtld_exit); 2707 rtld_exit_ptr = rtld_nop_exit; 2708 } 2709 2710 /* 2711 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2712 * When this happens, DT_INIT is processed first. 2713 */ 2714 if (elm->obj->init != (Elf_Addr)NULL) { 2715 dbg("calling init function for %s at %p", elm->obj->path, 2716 (void *)elm->obj->init); 2717 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2718 0, 0, elm->obj->path); 2719 call_initfini_pointer(elm->obj, elm->obj->init); 2720 } 2721 init_addr = (Elf_Addr *)elm->obj->init_array; 2722 if (init_addr != NULL) { 2723 for (index = 0; index < elm->obj->init_array_num; index++) { 2724 if (init_addr[index] != 0 && init_addr[index] != 1) { 2725 dbg("calling init function for %s at %p", elm->obj->path, 2726 (void *)init_addr[index]); 2727 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2728 (void *)init_addr[index], 0, 0, elm->obj->path); 2729 call_init_pointer(elm->obj, init_addr[index]); 2730 } 2731 } 2732 } 2733 wlock_acquire(rtld_bind_lock, lockstate); 2734 unhold_object(elm->obj); 2735 } 2736 errmsg_restore(saved_msg); 2737} 2738 2739static void 2740objlist_clear(Objlist *list) 2741{ 2742 Objlist_Entry *elm; 2743 2744 while (!STAILQ_EMPTY(list)) { 2745 elm = STAILQ_FIRST(list); 2746 STAILQ_REMOVE_HEAD(list, link); 2747 free(elm); 2748 } 2749} 2750 2751static Objlist_Entry * 2752objlist_find(Objlist *list, const Obj_Entry *obj) 2753{ 2754 Objlist_Entry *elm; 2755 2756 STAILQ_FOREACH(elm, list, link) 2757 if (elm->obj == obj) 2758 return elm; 2759 return NULL; 2760} 2761 2762static void 2763objlist_init(Objlist *list) 2764{ 2765 STAILQ_INIT(list); 2766} 2767 2768static void 2769objlist_push_head(Objlist *list, Obj_Entry *obj) 2770{ 2771 Objlist_Entry *elm; 2772 2773 elm = NEW(Objlist_Entry); 2774 elm->obj = obj; 2775 STAILQ_INSERT_HEAD(list, elm, link); 2776} 2777 2778static void 2779objlist_push_tail(Objlist *list, Obj_Entry *obj) 2780{ 2781 Objlist_Entry *elm; 2782 2783 elm = NEW(Objlist_Entry); 2784 elm->obj = obj; 2785 STAILQ_INSERT_TAIL(list, elm, link); 2786} 2787 2788static void 2789objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2790{ 2791 Objlist_Entry *elm, *listelm; 2792 2793 STAILQ_FOREACH(listelm, list, link) { 2794 if (listelm->obj == listobj) 2795 break; 2796 } 2797 elm = NEW(Objlist_Entry); 2798 elm->obj = obj; 2799 if (listelm != NULL) 2800 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2801 else 2802 STAILQ_INSERT_TAIL(list, elm, link); 2803} 2804 2805static void 2806objlist_remove(Objlist *list, Obj_Entry *obj) 2807{ 2808 Objlist_Entry *elm; 2809 2810 if ((elm = objlist_find(list, obj)) != NULL) { 2811 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2812 free(elm); 2813 } 2814} 2815 2816/* 2817 * Relocate dag rooted in the specified object. 2818 * Returns 0 on success, or -1 on failure. 2819 */ 2820 2821static int 2822relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2823 int flags, RtldLockState *lockstate) 2824{ 2825 Objlist_Entry *elm; 2826 int error; 2827 2828 error = 0; 2829 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2830 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2831 lockstate); 2832 if (error == -1) 2833 break; 2834 } 2835 return (error); 2836} 2837 2838/* 2839 * Prepare for, or clean after, relocating an object marked with 2840 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2841 * segments are remapped read-write. After relocations are done, the 2842 * segment's permissions are returned back to the modes specified in 2843 * the phdrs. If any relocation happened, or always for wired 2844 * program, COW is triggered. 2845 */ 2846static int 2847reloc_textrel_prot(Obj_Entry *obj, bool before) 2848{ 2849 const Elf_Phdr *ph; 2850 void *base; 2851 size_t l, sz; 2852 int prot; 2853 2854 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2855 l--, ph++) { 2856 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2857 continue; 2858 base = obj->relocbase + trunc_page(ph->p_vaddr); 2859 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2860 trunc_page(ph->p_vaddr); 2861 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2862 if (mprotect(base, sz, prot) == -1) { 2863 _rtld_error("%s: Cannot write-%sable text segment: %s", 2864 obj->path, before ? "en" : "dis", 2865 rtld_strerror(errno)); 2866 return (-1); 2867 } 2868 } 2869 return (0); 2870} 2871 2872/* 2873 * Relocate single object. 2874 * Returns 0 on success, or -1 on failure. 2875 */ 2876static int 2877relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2878 int flags, RtldLockState *lockstate) 2879{ 2880 2881 if (obj->relocated) 2882 return (0); 2883 obj->relocated = true; 2884 if (obj != rtldobj) 2885 dbg("relocating \"%s\"", obj->path); 2886 2887 if (obj->symtab == NULL || obj->strtab == NULL || 2888 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2889 _rtld_error("%s: Shared object has no run-time symbol table", 2890 obj->path); 2891 return (-1); 2892 } 2893 2894 /* There are relocations to the write-protected text segment. */ 2895 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2896 return (-1); 2897 2898 /* Process the non-PLT non-IFUNC relocations. */ 2899 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2900 return (-1); 2901 2902 /* Re-protected the text segment. */ 2903 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2904 return (-1); 2905 2906 /* Set the special PLT or GOT entries. */ 2907 init_pltgot(obj); 2908 2909 /* Process the PLT relocations. */ 2910 if (reloc_plt(obj) == -1) 2911 return (-1); 2912 /* Relocate the jump slots if we are doing immediate binding. */ 2913 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, 2914 lockstate) == -1) 2915 return (-1); 2916 2917 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2918 return (-1); 2919 2920 /* 2921 * Set up the magic number and version in the Obj_Entry. These 2922 * were checked in the crt1.o from the original ElfKit, so we 2923 * set them for backward compatibility. 2924 */ 2925 obj->magic = RTLD_MAGIC; 2926 obj->version = RTLD_VERSION; 2927 2928 return (0); 2929} 2930 2931/* 2932 * Relocate newly-loaded shared objects. The argument is a pointer to 2933 * the Obj_Entry for the first such object. All objects from the first 2934 * to the end of the list of objects are relocated. Returns 0 on success, 2935 * or -1 on failure. 2936 */ 2937static int 2938relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2939 int flags, RtldLockState *lockstate) 2940{ 2941 Obj_Entry *obj; 2942 int error; 2943 2944 for (error = 0, obj = first; obj != NULL; 2945 obj = TAILQ_NEXT(obj, next)) { 2946 if (obj->marker) 2947 continue; 2948 error = relocate_object(obj, bind_now, rtldobj, flags, 2949 lockstate); 2950 if (error == -1) 2951 break; 2952 } 2953 return (error); 2954} 2955 2956/* 2957 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2958 * referencing STT_GNU_IFUNC symbols is postponed till the other 2959 * relocations are done. The indirect functions specified as 2960 * ifunc are allowed to call other symbols, so we need to have 2961 * objects relocated before asking for resolution from indirects. 2962 * 2963 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2964 * instead of the usual lazy handling of PLT slots. It is 2965 * consistent with how GNU does it. 2966 */ 2967static int 2968resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2969 RtldLockState *lockstate) 2970{ 2971 2972 if (obj->ifuncs_resolved) 2973 return (0); 2974 obj->ifuncs_resolved = true; 2975 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc)) 2976 return (0); 2977 if (obj_disable_relro(obj) == -1 || 2978 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || 2979 ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2980 reloc_gnu_ifunc(obj, flags, lockstate) == -1) || 2981 obj_enforce_relro(obj) == -1) 2982 return (-1); 2983 return (0); 2984} 2985 2986static int 2987initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2988 RtldLockState *lockstate) 2989{ 2990 Objlist_Entry *elm; 2991 Obj_Entry *obj; 2992 2993 STAILQ_FOREACH(elm, list, link) { 2994 obj = elm->obj; 2995 if (obj->marker) 2996 continue; 2997 if (resolve_object_ifunc(obj, bind_now, flags, 2998 lockstate) == -1) 2999 return (-1); 3000 } 3001 return (0); 3002} 3003 3004/* 3005 * Cleanup procedure. It will be called (by the atexit mechanism) just 3006 * before the process exits. 3007 */ 3008static void 3009rtld_exit(void) 3010{ 3011 RtldLockState lockstate; 3012 3013 wlock_acquire(rtld_bind_lock, &lockstate); 3014 dbg("rtld_exit()"); 3015 objlist_call_fini(&list_fini, NULL, &lockstate); 3016 /* No need to remove the items from the list, since we are exiting. */ 3017 if (!libmap_disable) 3018 lm_fini(); 3019 lock_release(rtld_bind_lock, &lockstate); 3020} 3021 3022static void 3023rtld_nop_exit(void) 3024{ 3025} 3026 3027/* 3028 * Iterate over a search path, translate each element, and invoke the 3029 * callback on the result. 3030 */ 3031static void * 3032path_enumerate(const char *path, path_enum_proc callback, 3033 const char *refobj_path, void *arg) 3034{ 3035 const char *trans; 3036 if (path == NULL) 3037 return (NULL); 3038 3039 path += strspn(path, ":;"); 3040 while (*path != '\0') { 3041 size_t len; 3042 char *res; 3043 3044 len = strcspn(path, ":;"); 3045 trans = lm_findn(refobj_path, path, len); 3046 if (trans) 3047 res = callback(trans, strlen(trans), arg); 3048 else 3049 res = callback(path, len, arg); 3050 3051 if (res != NULL) 3052 return (res); 3053 3054 path += len; 3055 path += strspn(path, ":;"); 3056 } 3057 3058 return (NULL); 3059} 3060 3061struct try_library_args { 3062 const char *name; 3063 size_t namelen; 3064 char *buffer; 3065 size_t buflen; 3066 int fd; 3067}; 3068 3069static void * 3070try_library_path(const char *dir, size_t dirlen, void *param) 3071{ 3072 struct try_library_args *arg; 3073 int fd; 3074 3075 arg = param; 3076 if (*dir == '/' || trust) { 3077 char *pathname; 3078 3079 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 3080 return (NULL); 3081 3082 pathname = arg->buffer; 3083 strncpy(pathname, dir, dirlen); 3084 pathname[dirlen] = '/'; 3085 strcpy(pathname + dirlen + 1, arg->name); 3086 3087 dbg(" Trying \"%s\"", pathname); 3088 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); 3089 if (fd >= 0) { 3090 dbg(" Opened \"%s\", fd %d", pathname, fd); 3091 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 3092 strcpy(pathname, arg->buffer); 3093 arg->fd = fd; 3094 return (pathname); 3095 } else { 3096 dbg(" Failed to open \"%s\": %s", 3097 pathname, rtld_strerror(errno)); 3098 } 3099 } 3100 return (NULL); 3101} 3102 3103static char * 3104search_library_path(const char *name, const char *path, 3105 const char *refobj_path, int *fdp) 3106{ 3107 char *p; 3108 struct try_library_args arg; 3109 3110 if (path == NULL) 3111 return NULL; 3112 3113 arg.name = name; 3114 arg.namelen = strlen(name); 3115 arg.buffer = xmalloc(PATH_MAX); 3116 arg.buflen = PATH_MAX; 3117 arg.fd = -1; 3118 3119 p = path_enumerate(path, try_library_path, refobj_path, &arg); 3120 *fdp = arg.fd; 3121 3122 free(arg.buffer); 3123 3124 return (p); 3125} 3126 3127 3128/* 3129 * Finds the library with the given name using the directory descriptors 3130 * listed in the LD_LIBRARY_PATH_FDS environment variable. 3131 * 3132 * Returns a freshly-opened close-on-exec file descriptor for the library, 3133 * or -1 if the library cannot be found. 3134 */ 3135static char * 3136search_library_pathfds(const char *name, const char *path, int *fdp) 3137{ 3138 char *envcopy, *fdstr, *found, *last_token; 3139 size_t len; 3140 int dirfd, fd; 3141 3142 dbg("%s('%s', '%s', fdp)", __func__, name, path); 3143 3144 /* Don't load from user-specified libdirs into setuid binaries. */ 3145 if (!trust) 3146 return (NULL); 3147 3148 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 3149 if (path == NULL) 3150 return (NULL); 3151 3152 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 3153 if (name[0] == '/') { 3154 dbg("Absolute path (%s) passed to %s", name, __func__); 3155 return (NULL); 3156 } 3157 3158 /* 3159 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 3160 * copy of the path, as strtok_r rewrites separator tokens 3161 * with '\0'. 3162 */ 3163 found = NULL; 3164 envcopy = xstrdup(path); 3165 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 3166 fdstr = strtok_r(NULL, ":", &last_token)) { 3167 dirfd = parse_integer(fdstr); 3168 if (dirfd < 0) { 3169 _rtld_error("failed to parse directory FD: '%s'", 3170 fdstr); 3171 break; 3172 } 3173 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 3174 if (fd >= 0) { 3175 *fdp = fd; 3176 len = strlen(fdstr) + strlen(name) + 3; 3177 found = xmalloc(len); 3178 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 3179 _rtld_error("error generating '%d/%s'", 3180 dirfd, name); 3181 rtld_die(); 3182 } 3183 dbg("open('%s') => %d", found, fd); 3184 break; 3185 } 3186 } 3187 free(envcopy); 3188 3189 return (found); 3190} 3191 3192 3193int 3194dlclose(void *handle) 3195{ 3196 RtldLockState lockstate; 3197 int error; 3198 3199 wlock_acquire(rtld_bind_lock, &lockstate); 3200 error = dlclose_locked(handle, &lockstate); 3201 lock_release(rtld_bind_lock, &lockstate); 3202 return (error); 3203} 3204 3205static int 3206dlclose_locked(void *handle, RtldLockState *lockstate) 3207{ 3208 Obj_Entry *root; 3209 3210 root = dlcheck(handle); 3211 if (root == NULL) 3212 return -1; 3213 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3214 root->path); 3215 3216 /* Unreference the object and its dependencies. */ 3217 root->dl_refcount--; 3218 3219 if (root->refcount == 1) { 3220 /* 3221 * The object will be no longer referenced, so we must unload it. 3222 * First, call the fini functions. 3223 */ 3224 objlist_call_fini(&list_fini, root, lockstate); 3225 3226 unref_dag(root); 3227 3228 /* Finish cleaning up the newly-unreferenced objects. */ 3229 GDB_STATE(RT_DELETE,&root->linkmap); 3230 unload_object(root, lockstate); 3231 GDB_STATE(RT_CONSISTENT,NULL); 3232 } else 3233 unref_dag(root); 3234 3235 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3236 return 0; 3237} 3238 3239char * 3240dlerror(void) 3241{ 3242 char *msg = error_message; 3243 error_message = NULL; 3244 return msg; 3245} 3246 3247/* 3248 * This function is deprecated and has no effect. 3249 */ 3250void 3251dllockinit(void *context, 3252 void *(*lock_create)(void *context), 3253 void (*rlock_acquire)(void *lock), 3254 void (*wlock_acquire)(void *lock), 3255 void (*lock_release)(void *lock), 3256 void (*lock_destroy)(void *lock), 3257 void (*context_destroy)(void *context)) 3258{ 3259 static void *cur_context; 3260 static void (*cur_context_destroy)(void *); 3261 3262 /* Just destroy the context from the previous call, if necessary. */ 3263 if (cur_context_destroy != NULL) 3264 cur_context_destroy(cur_context); 3265 cur_context = context; 3266 cur_context_destroy = context_destroy; 3267} 3268 3269void * 3270dlopen(const char *name, int mode) 3271{ 3272 3273 return (rtld_dlopen(name, -1, mode)); 3274} 3275 3276void * 3277fdlopen(int fd, int mode) 3278{ 3279 3280 return (rtld_dlopen(NULL, fd, mode)); 3281} 3282 3283static void * 3284rtld_dlopen(const char *name, int fd, int mode) 3285{ 3286 RtldLockState lockstate; 3287 int lo_flags; 3288 3289 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3290 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3291 if (ld_tracing != NULL) { 3292 rlock_acquire(rtld_bind_lock, &lockstate); 3293 if (sigsetjmp(lockstate.env, 0) != 0) 3294 lock_upgrade(rtld_bind_lock, &lockstate); 3295 environ = (char **)*get_program_var_addr("environ", &lockstate); 3296 lock_release(rtld_bind_lock, &lockstate); 3297 } 3298 lo_flags = RTLD_LO_DLOPEN; 3299 if (mode & RTLD_NODELETE) 3300 lo_flags |= RTLD_LO_NODELETE; 3301 if (mode & RTLD_NOLOAD) 3302 lo_flags |= RTLD_LO_NOLOAD; 3303 if (mode & RTLD_DEEPBIND) 3304 lo_flags |= RTLD_LO_DEEPBIND; 3305 if (ld_tracing != NULL) 3306 lo_flags |= RTLD_LO_TRACE; 3307 3308 return (dlopen_object(name, fd, obj_main, lo_flags, 3309 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3310} 3311 3312static void 3313dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) 3314{ 3315 3316 obj->dl_refcount--; 3317 unref_dag(obj); 3318 if (obj->refcount == 0) 3319 unload_object(obj, lockstate); 3320} 3321 3322static Obj_Entry * 3323dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3324 int mode, RtldLockState *lockstate) 3325{ 3326 Obj_Entry *old_obj_tail; 3327 Obj_Entry *obj; 3328 Objlist initlist; 3329 RtldLockState mlockstate; 3330 int result; 3331 3332 objlist_init(&initlist); 3333 3334 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3335 wlock_acquire(rtld_bind_lock, &mlockstate); 3336 lockstate = &mlockstate; 3337 } 3338 GDB_STATE(RT_ADD,NULL); 3339 3340 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3341 obj = NULL; 3342 if (name == NULL && fd == -1) { 3343 obj = obj_main; 3344 obj->refcount++; 3345 } else { 3346 obj = load_object(name, fd, refobj, lo_flags); 3347 } 3348 3349 if (obj) { 3350 obj->dl_refcount++; 3351 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3352 objlist_push_tail(&list_global, obj); 3353 if (globallist_next(old_obj_tail) != NULL) { 3354 /* We loaded something new. */ 3355 assert(globallist_next(old_obj_tail) == obj); 3356 if ((lo_flags & RTLD_LO_DEEPBIND) != 0) 3357 obj->symbolic = true; 3358 result = 0; 3359 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3360 !allocate_tls_offset(obj)) { 3361 _rtld_error("%s: No space available " 3362 "for static Thread Local Storage", obj->path); 3363 result = -1; 3364 } 3365 if (result != -1) 3366 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | 3367 RTLD_LO_EARLY)); 3368 init_dag(obj); 3369 ref_dag(obj); 3370 if (result != -1) 3371 result = rtld_verify_versions(&obj->dagmembers); 3372 if (result != -1 && ld_tracing) 3373 goto trace; 3374 if (result == -1 || relocate_object_dag(obj, 3375 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3376 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3377 lockstate) == -1) { 3378 dlopen_cleanup(obj, lockstate); 3379 obj = NULL; 3380 } else if (lo_flags & RTLD_LO_EARLY) { 3381 /* 3382 * Do not call the init functions for early loaded 3383 * filtees. The image is still not initialized enough 3384 * for them to work. 3385 * 3386 * Our object is found by the global object list and 3387 * will be ordered among all init calls done right 3388 * before transferring control to main. 3389 */ 3390 } else { 3391 /* Make list of init functions to call. */ 3392 initlist_add_objects(obj, obj, &initlist); 3393 } 3394 /* 3395 * Process all no_delete or global objects here, given 3396 * them own DAGs to prevent their dependencies from being 3397 * unloaded. This has to be done after we have loaded all 3398 * of the dependencies, so that we do not miss any. 3399 */ 3400 if (obj != NULL) 3401 process_z(obj); 3402 } else { 3403 /* 3404 * Bump the reference counts for objects on this DAG. If 3405 * this is the first dlopen() call for the object that was 3406 * already loaded as a dependency, initialize the dag 3407 * starting at it. 3408 */ 3409 init_dag(obj); 3410 ref_dag(obj); 3411 3412 if ((lo_flags & RTLD_LO_TRACE) != 0) 3413 goto trace; 3414 } 3415 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3416 obj->z_nodelete) && !obj->ref_nodel) { 3417 dbg("obj %s nodelete", obj->path); 3418 ref_dag(obj); 3419 obj->z_nodelete = obj->ref_nodel = true; 3420 } 3421 } 3422 3423 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3424 name); 3425 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3426 3427 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3428 map_stacks_exec(lockstate); 3429 if (obj != NULL) 3430 distribute_static_tls(&initlist, lockstate); 3431 } 3432 3433 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3434 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3435 lockstate) == -1) { 3436 objlist_clear(&initlist); 3437 dlopen_cleanup(obj, lockstate); 3438 if (lockstate == &mlockstate) 3439 lock_release(rtld_bind_lock, lockstate); 3440 return (NULL); 3441 } 3442 3443 if (!(lo_flags & RTLD_LO_EARLY)) { 3444 /* Call the init functions. */ 3445 objlist_call_init(&initlist, lockstate); 3446 } 3447 objlist_clear(&initlist); 3448 if (lockstate == &mlockstate) 3449 lock_release(rtld_bind_lock, lockstate); 3450 return obj; 3451trace: 3452 trace_loaded_objects(obj); 3453 if (lockstate == &mlockstate) 3454 lock_release(rtld_bind_lock, lockstate); 3455 exit(0); 3456} 3457 3458static void * 3459do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3460 int flags) 3461{ 3462 DoneList donelist; 3463 const Obj_Entry *obj, *defobj; 3464 const Elf_Sym *def; 3465 SymLook req; 3466 RtldLockState lockstate; 3467 tls_index ti; 3468 void *sym; 3469 int res; 3470 3471 def = NULL; 3472 defobj = NULL; 3473 symlook_init(&req, name); 3474 req.ventry = ve; 3475 req.flags = flags | SYMLOOK_IN_PLT; 3476 req.lockstate = &lockstate; 3477 3478 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3479 rlock_acquire(rtld_bind_lock, &lockstate); 3480 if (sigsetjmp(lockstate.env, 0) != 0) 3481 lock_upgrade(rtld_bind_lock, &lockstate); 3482 if (handle == NULL || handle == RTLD_NEXT || 3483 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3484 3485 if ((obj = obj_from_addr(retaddr)) == NULL) { 3486 _rtld_error("Cannot determine caller's shared object"); 3487 lock_release(rtld_bind_lock, &lockstate); 3488 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3489 return NULL; 3490 } 3491 if (handle == NULL) { /* Just the caller's shared object. */ 3492 res = symlook_obj(&req, obj); 3493 if (res == 0) { 3494 def = req.sym_out; 3495 defobj = req.defobj_out; 3496 } 3497 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3498 handle == RTLD_SELF) { /* ... caller included */ 3499 if (handle == RTLD_NEXT) 3500 obj = globallist_next(obj); 3501 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3502 if (obj->marker) 3503 continue; 3504 res = symlook_obj(&req, obj); 3505 if (res == 0) { 3506 if (def == NULL || 3507 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3508 def = req.sym_out; 3509 defobj = req.defobj_out; 3510 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3511 break; 3512 } 3513 } 3514 } 3515 /* 3516 * Search the dynamic linker itself, and possibly resolve the 3517 * symbol from there. This is how the application links to 3518 * dynamic linker services such as dlopen. 3519 */ 3520 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3521 res = symlook_obj(&req, &obj_rtld); 3522 if (res == 0) { 3523 def = req.sym_out; 3524 defobj = req.defobj_out; 3525 } 3526 } 3527 } else { 3528 assert(handle == RTLD_DEFAULT); 3529 res = symlook_default(&req, obj); 3530 if (res == 0) { 3531 defobj = req.defobj_out; 3532 def = req.sym_out; 3533 } 3534 } 3535 } else { 3536 if ((obj = dlcheck(handle)) == NULL) { 3537 lock_release(rtld_bind_lock, &lockstate); 3538 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3539 return NULL; 3540 } 3541 3542 donelist_init(&donelist); 3543 if (obj->mainprog) { 3544 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3545 res = symlook_global(&req, &donelist); 3546 if (res == 0) { 3547 def = req.sym_out; 3548 defobj = req.defobj_out; 3549 } 3550 /* 3551 * Search the dynamic linker itself, and possibly resolve the 3552 * symbol from there. This is how the application links to 3553 * dynamic linker services such as dlopen. 3554 */ 3555 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3556 res = symlook_obj(&req, &obj_rtld); 3557 if (res == 0) { 3558 def = req.sym_out; 3559 defobj = req.defobj_out; 3560 } 3561 } 3562 } 3563 else { 3564 /* Search the whole DAG rooted at the given object. */ 3565 res = symlook_list(&req, &obj->dagmembers, &donelist); 3566 if (res == 0) { 3567 def = req.sym_out; 3568 defobj = req.defobj_out; 3569 } 3570 } 3571 } 3572 3573 if (def != NULL) { 3574 lock_release(rtld_bind_lock, &lockstate); 3575 3576 /* 3577 * The value required by the caller is derived from the value 3578 * of the symbol. this is simply the relocated value of the 3579 * symbol. 3580 */ 3581 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3582 sym = make_function_pointer(def, defobj); 3583 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3584 sym = rtld_resolve_ifunc(defobj, def); 3585 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3586 ti.ti_module = defobj->tlsindex; 3587 ti.ti_offset = def->st_value; 3588 sym = __tls_get_addr(&ti); 3589 } else 3590 sym = defobj->relocbase + def->st_value; 3591 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3592 return (sym); 3593 } 3594 3595 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3596 ve != NULL ? ve->name : ""); 3597 lock_release(rtld_bind_lock, &lockstate); 3598 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3599 return NULL; 3600} 3601 3602void * 3603dlsym(void *handle, const char *name) 3604{ 3605 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3606 SYMLOOK_DLSYM); 3607} 3608 3609dlfunc_t 3610dlfunc(void *handle, const char *name) 3611{ 3612 union { 3613 void *d; 3614 dlfunc_t f; 3615 } rv; 3616 3617 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3618 SYMLOOK_DLSYM); 3619 return (rv.f); 3620} 3621 3622void * 3623dlvsym(void *handle, const char *name, const char *version) 3624{ 3625 Ver_Entry ventry; 3626 3627 ventry.name = version; 3628 ventry.file = NULL; 3629 ventry.hash = elf_hash(version); 3630 ventry.flags= 0; 3631 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3632 SYMLOOK_DLSYM); 3633} 3634 3635int 3636_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3637{ 3638 const Obj_Entry *obj; 3639 RtldLockState lockstate; 3640 3641 rlock_acquire(rtld_bind_lock, &lockstate); 3642 obj = obj_from_addr(addr); 3643 if (obj == NULL) { 3644 _rtld_error("No shared object contains address"); 3645 lock_release(rtld_bind_lock, &lockstate); 3646 return (0); 3647 } 3648 rtld_fill_dl_phdr_info(obj, phdr_info); 3649 lock_release(rtld_bind_lock, &lockstate); 3650 return (1); 3651} 3652 3653int 3654dladdr(const void *addr, Dl_info *info) 3655{ 3656 const Obj_Entry *obj; 3657 const Elf_Sym *def; 3658 void *symbol_addr; 3659 unsigned long symoffset; 3660 RtldLockState lockstate; 3661 3662 rlock_acquire(rtld_bind_lock, &lockstate); 3663 obj = obj_from_addr(addr); 3664 if (obj == NULL) { 3665 _rtld_error("No shared object contains address"); 3666 lock_release(rtld_bind_lock, &lockstate); 3667 return 0; 3668 } 3669 info->dli_fname = obj->path; 3670 info->dli_fbase = obj->mapbase; 3671 info->dli_saddr = (void *)0; 3672 info->dli_sname = NULL; 3673 3674 /* 3675 * Walk the symbol list looking for the symbol whose address is 3676 * closest to the address sent in. 3677 */ 3678 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3679 def = obj->symtab + symoffset; 3680 3681 /* 3682 * For skip the symbol if st_shndx is either SHN_UNDEF or 3683 * SHN_COMMON. 3684 */ 3685 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3686 continue; 3687 3688 /* 3689 * If the symbol is greater than the specified address, or if it 3690 * is further away from addr than the current nearest symbol, 3691 * then reject it. 3692 */ 3693 symbol_addr = obj->relocbase + def->st_value; 3694 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3695 continue; 3696 3697 /* Update our idea of the nearest symbol. */ 3698 info->dli_sname = obj->strtab + def->st_name; 3699 info->dli_saddr = symbol_addr; 3700 3701 /* Exact match? */ 3702 if (info->dli_saddr == addr) 3703 break; 3704 } 3705 lock_release(rtld_bind_lock, &lockstate); 3706 return 1; 3707} 3708 3709int 3710dlinfo(void *handle, int request, void *p) 3711{ 3712 const Obj_Entry *obj; 3713 RtldLockState lockstate; 3714 int error; 3715 3716 rlock_acquire(rtld_bind_lock, &lockstate); 3717 3718 if (handle == NULL || handle == RTLD_SELF) { 3719 void *retaddr; 3720 3721 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3722 if ((obj = obj_from_addr(retaddr)) == NULL) 3723 _rtld_error("Cannot determine caller's shared object"); 3724 } else 3725 obj = dlcheck(handle); 3726 3727 if (obj == NULL) { 3728 lock_release(rtld_bind_lock, &lockstate); 3729 return (-1); 3730 } 3731 3732 error = 0; 3733 switch (request) { 3734 case RTLD_DI_LINKMAP: 3735 *((struct link_map const **)p) = &obj->linkmap; 3736 break; 3737 case RTLD_DI_ORIGIN: 3738 error = rtld_dirname(obj->path, p); 3739 break; 3740 3741 case RTLD_DI_SERINFOSIZE: 3742 case RTLD_DI_SERINFO: 3743 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3744 break; 3745 3746 default: 3747 _rtld_error("Invalid request %d passed to dlinfo()", request); 3748 error = -1; 3749 } 3750 3751 lock_release(rtld_bind_lock, &lockstate); 3752 3753 return (error); 3754} 3755 3756static void 3757rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3758{ 3759 3760 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3761 phdr_info->dlpi_name = obj->path; 3762 phdr_info->dlpi_phdr = obj->phdr; 3763 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3764 phdr_info->dlpi_tls_modid = obj->tlsindex; 3765 phdr_info->dlpi_tls_data = obj->tlsinit; 3766 phdr_info->dlpi_adds = obj_loads; 3767 phdr_info->dlpi_subs = obj_loads - obj_count; 3768} 3769 3770int 3771dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3772{ 3773 struct dl_phdr_info phdr_info; 3774 Obj_Entry *obj, marker; 3775 RtldLockState bind_lockstate, phdr_lockstate; 3776 int error; 3777 3778 init_marker(&marker); 3779 error = 0; 3780 3781 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3782 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3783 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3784 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3785 rtld_fill_dl_phdr_info(obj, &phdr_info); 3786 hold_object(obj); 3787 lock_release(rtld_bind_lock, &bind_lockstate); 3788 3789 error = callback(&phdr_info, sizeof phdr_info, param); 3790 3791 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3792 unhold_object(obj); 3793 obj = globallist_next(&marker); 3794 TAILQ_REMOVE(&obj_list, &marker, next); 3795 if (error != 0) { 3796 lock_release(rtld_bind_lock, &bind_lockstate); 3797 lock_release(rtld_phdr_lock, &phdr_lockstate); 3798 return (error); 3799 } 3800 } 3801 3802 if (error == 0) { 3803 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3804 lock_release(rtld_bind_lock, &bind_lockstate); 3805 error = callback(&phdr_info, sizeof(phdr_info), param); 3806 } 3807 lock_release(rtld_phdr_lock, &phdr_lockstate); 3808 return (error); 3809} 3810 3811static void * 3812fill_search_info(const char *dir, size_t dirlen, void *param) 3813{ 3814 struct fill_search_info_args *arg; 3815 3816 arg = param; 3817 3818 if (arg->request == RTLD_DI_SERINFOSIZE) { 3819 arg->serinfo->dls_cnt ++; 3820 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3821 } else { 3822 struct dl_serpath *s_entry; 3823 3824 s_entry = arg->serpath; 3825 s_entry->dls_name = arg->strspace; 3826 s_entry->dls_flags = arg->flags; 3827 3828 strncpy(arg->strspace, dir, dirlen); 3829 arg->strspace[dirlen] = '\0'; 3830 3831 arg->strspace += dirlen + 1; 3832 arg->serpath++; 3833 } 3834 3835 return (NULL); 3836} 3837 3838static int 3839do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3840{ 3841 struct dl_serinfo _info; 3842 struct fill_search_info_args args; 3843 3844 args.request = RTLD_DI_SERINFOSIZE; 3845 args.serinfo = &_info; 3846 3847 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3848 _info.dls_cnt = 0; 3849 3850 path_enumerate(obj->rpath, fill_search_info, NULL, &args); 3851 path_enumerate(ld_library_path, fill_search_info, NULL, &args); 3852 path_enumerate(obj->runpath, fill_search_info, NULL, &args); 3853 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); 3854 if (!obj->z_nodeflib) 3855 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); 3856 3857 3858 if (request == RTLD_DI_SERINFOSIZE) { 3859 info->dls_size = _info.dls_size; 3860 info->dls_cnt = _info.dls_cnt; 3861 return (0); 3862 } 3863 3864 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3865 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3866 return (-1); 3867 } 3868 3869 args.request = RTLD_DI_SERINFO; 3870 args.serinfo = info; 3871 args.serpath = &info->dls_serpath[0]; 3872 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3873 3874 args.flags = LA_SER_RUNPATH; 3875 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) 3876 return (-1); 3877 3878 args.flags = LA_SER_LIBPATH; 3879 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) 3880 return (-1); 3881 3882 args.flags = LA_SER_RUNPATH; 3883 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) 3884 return (-1); 3885 3886 args.flags = LA_SER_CONFIG; 3887 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) 3888 != NULL) 3889 return (-1); 3890 3891 args.flags = LA_SER_DEFAULT; 3892 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, 3893 fill_search_info, NULL, &args) != NULL) 3894 return (-1); 3895 return (0); 3896} 3897 3898static int 3899rtld_dirname(const char *path, char *bname) 3900{ 3901 const char *endp; 3902 3903 /* Empty or NULL string gets treated as "." */ 3904 if (path == NULL || *path == '\0') { 3905 bname[0] = '.'; 3906 bname[1] = '\0'; 3907 return (0); 3908 } 3909 3910 /* Strip trailing slashes */ 3911 endp = path + strlen(path) - 1; 3912 while (endp > path && *endp == '/') 3913 endp--; 3914 3915 /* Find the start of the dir */ 3916 while (endp > path && *endp != '/') 3917 endp--; 3918 3919 /* Either the dir is "/" or there are no slashes */ 3920 if (endp == path) { 3921 bname[0] = *endp == '/' ? '/' : '.'; 3922 bname[1] = '\0'; 3923 return (0); 3924 } else { 3925 do { 3926 endp--; 3927 } while (endp > path && *endp == '/'); 3928 } 3929 3930 if (endp - path + 2 > PATH_MAX) 3931 { 3932 _rtld_error("Filename is too long: %s", path); 3933 return(-1); 3934 } 3935 3936 strncpy(bname, path, endp - path + 1); 3937 bname[endp - path + 1] = '\0'; 3938 return (0); 3939} 3940 3941static int 3942rtld_dirname_abs(const char *path, char *base) 3943{ 3944 char *last; 3945 3946 if (realpath(path, base) == NULL) { 3947 _rtld_error("realpath \"%s\" failed (%s)", path, 3948 rtld_strerror(errno)); 3949 return (-1); 3950 } 3951 dbg("%s -> %s", path, base); 3952 last = strrchr(base, '/'); 3953 if (last == NULL) { 3954 _rtld_error("non-abs result from realpath \"%s\"", path); 3955 return (-1); 3956 } 3957 if (last != base) 3958 *last = '\0'; 3959 return (0); 3960} 3961 3962static void 3963linkmap_add(Obj_Entry *obj) 3964{ 3965 struct link_map *l = &obj->linkmap; 3966 struct link_map *prev; 3967 3968 obj->linkmap.l_name = obj->path; 3969 obj->linkmap.l_addr = obj->mapbase; 3970 obj->linkmap.l_ld = obj->dynamic; 3971#ifdef __mips__ 3972 /* GDB needs load offset on MIPS to use the symbols */ 3973 obj->linkmap.l_offs = obj->relocbase; 3974#endif 3975 3976 if (r_debug.r_map == NULL) { 3977 r_debug.r_map = l; 3978 return; 3979 } 3980 3981 /* 3982 * Scan to the end of the list, but not past the entry for the 3983 * dynamic linker, which we want to keep at the very end. 3984 */ 3985 for (prev = r_debug.r_map; 3986 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3987 prev = prev->l_next) 3988 ; 3989 3990 /* Link in the new entry. */ 3991 l->l_prev = prev; 3992 l->l_next = prev->l_next; 3993 if (l->l_next != NULL) 3994 l->l_next->l_prev = l; 3995 prev->l_next = l; 3996} 3997 3998static void 3999linkmap_delete(Obj_Entry *obj) 4000{ 4001 struct link_map *l = &obj->linkmap; 4002 4003 if (l->l_prev == NULL) { 4004 if ((r_debug.r_map = l->l_next) != NULL) 4005 l->l_next->l_prev = NULL; 4006 return; 4007 } 4008 4009 if ((l->l_prev->l_next = l->l_next) != NULL) 4010 l->l_next->l_prev = l->l_prev; 4011} 4012 4013/* 4014 * Function for the debugger to set a breakpoint on to gain control. 4015 * 4016 * The two parameters allow the debugger to easily find and determine 4017 * what the runtime loader is doing and to whom it is doing it. 4018 * 4019 * When the loadhook trap is hit (r_debug_state, set at program 4020 * initialization), the arguments can be found on the stack: 4021 * 4022 * +8 struct link_map *m 4023 * +4 struct r_debug *rd 4024 * +0 RetAddr 4025 */ 4026void 4027r_debug_state(struct r_debug* rd, struct link_map *m) 4028{ 4029 /* 4030 * The following is a hack to force the compiler to emit calls to 4031 * this function, even when optimizing. If the function is empty, 4032 * the compiler is not obliged to emit any code for calls to it, 4033 * even when marked __noinline. However, gdb depends on those 4034 * calls being made. 4035 */ 4036 __compiler_membar(); 4037} 4038 4039/* 4040 * A function called after init routines have completed. This can be used to 4041 * break before a program's entry routine is called, and can be used when 4042 * main is not available in the symbol table. 4043 */ 4044void 4045_r_debug_postinit(struct link_map *m) 4046{ 4047 4048 /* See r_debug_state(). */ 4049 __compiler_membar(); 4050} 4051 4052static void 4053release_object(Obj_Entry *obj) 4054{ 4055 4056 if (obj->holdcount > 0) { 4057 obj->unholdfree = true; 4058 return; 4059 } 4060 munmap(obj->mapbase, obj->mapsize); 4061 linkmap_delete(obj); 4062 obj_free(obj); 4063} 4064 4065/* 4066 * Get address of the pointer variable in the main program. 4067 * Prefer non-weak symbol over the weak one. 4068 */ 4069static const void ** 4070get_program_var_addr(const char *name, RtldLockState *lockstate) 4071{ 4072 SymLook req; 4073 DoneList donelist; 4074 4075 symlook_init(&req, name); 4076 req.lockstate = lockstate; 4077 donelist_init(&donelist); 4078 if (symlook_global(&req, &donelist) != 0) 4079 return (NULL); 4080 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 4081 return ((const void **)make_function_pointer(req.sym_out, 4082 req.defobj_out)); 4083 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 4084 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 4085 else 4086 return ((const void **)(req.defobj_out->relocbase + 4087 req.sym_out->st_value)); 4088} 4089 4090/* 4091 * Set a pointer variable in the main program to the given value. This 4092 * is used to set key variables such as "environ" before any of the 4093 * init functions are called. 4094 */ 4095static void 4096set_program_var(const char *name, const void *value) 4097{ 4098 const void **addr; 4099 4100 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 4101 dbg("\"%s\": *%p <-- %p", name, addr, value); 4102 *addr = value; 4103 } 4104} 4105 4106/* 4107 * Search the global objects, including dependencies and main object, 4108 * for the given symbol. 4109 */ 4110static int 4111symlook_global(SymLook *req, DoneList *donelist) 4112{ 4113 SymLook req1; 4114 const Objlist_Entry *elm; 4115 int res; 4116 4117 symlook_init_from_req(&req1, req); 4118 4119 /* Search all objects loaded at program start up. */ 4120 if (req->defobj_out == NULL || 4121 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4122 res = symlook_list(&req1, &list_main, donelist); 4123 if (res == 0 && (req->defobj_out == NULL || 4124 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4125 req->sym_out = req1.sym_out; 4126 req->defobj_out = req1.defobj_out; 4127 assert(req->defobj_out != NULL); 4128 } 4129 } 4130 4131 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 4132 STAILQ_FOREACH(elm, &list_global, link) { 4133 if (req->defobj_out != NULL && 4134 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4135 break; 4136 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 4137 if (res == 0 && (req->defobj_out == NULL || 4138 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4139 req->sym_out = req1.sym_out; 4140 req->defobj_out = req1.defobj_out; 4141 assert(req->defobj_out != NULL); 4142 } 4143 } 4144 4145 return (req->sym_out != NULL ? 0 : ESRCH); 4146} 4147 4148/* 4149 * Given a symbol name in a referencing object, find the corresponding 4150 * definition of the symbol. Returns a pointer to the symbol, or NULL if 4151 * no definition was found. Returns a pointer to the Obj_Entry of the 4152 * defining object via the reference parameter DEFOBJ_OUT. 4153 */ 4154static int 4155symlook_default(SymLook *req, const Obj_Entry *refobj) 4156{ 4157 DoneList donelist; 4158 const Objlist_Entry *elm; 4159 SymLook req1; 4160 int res; 4161 4162 donelist_init(&donelist); 4163 symlook_init_from_req(&req1, req); 4164 4165 /* 4166 * Look first in the referencing object if linked symbolically, 4167 * and similarly handle protected symbols. 4168 */ 4169 res = symlook_obj(&req1, refobj); 4170 if (res == 0 && (refobj->symbolic || 4171 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 4172 req->sym_out = req1.sym_out; 4173 req->defobj_out = req1.defobj_out; 4174 assert(req->defobj_out != NULL); 4175 } 4176 if (refobj->symbolic || req->defobj_out != NULL) 4177 donelist_check(&donelist, refobj); 4178 4179 symlook_global(req, &donelist); 4180 4181 /* Search all dlopened DAGs containing the referencing object. */ 4182 STAILQ_FOREACH(elm, &refobj->dldags, link) { 4183 if (req->sym_out != NULL && 4184 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 4185 break; 4186 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 4187 if (res == 0 && (req->sym_out == NULL || 4188 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 4189 req->sym_out = req1.sym_out; 4190 req->defobj_out = req1.defobj_out; 4191 assert(req->defobj_out != NULL); 4192 } 4193 } 4194 4195 /* 4196 * Search the dynamic linker itself, and possibly resolve the 4197 * symbol from there. This is how the application links to 4198 * dynamic linker services such as dlopen. 4199 */ 4200 if (req->sym_out == NULL || 4201 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 4202 res = symlook_obj(&req1, &obj_rtld); 4203 if (res == 0) { 4204 req->sym_out = req1.sym_out; 4205 req->defobj_out = req1.defobj_out; 4206 assert(req->defobj_out != NULL); 4207 } 4208 } 4209 4210 return (req->sym_out != NULL ? 0 : ESRCH); 4211} 4212 4213static int 4214symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 4215{ 4216 const Elf_Sym *def; 4217 const Obj_Entry *defobj; 4218 const Objlist_Entry *elm; 4219 SymLook req1; 4220 int res; 4221 4222 def = NULL; 4223 defobj = NULL; 4224 STAILQ_FOREACH(elm, objlist, link) { 4225 if (donelist_check(dlp, elm->obj)) 4226 continue; 4227 symlook_init_from_req(&req1, req); 4228 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 4229 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4230 def = req1.sym_out; 4231 defobj = req1.defobj_out; 4232 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4233 break; 4234 } 4235 } 4236 } 4237 if (def != NULL) { 4238 req->sym_out = def; 4239 req->defobj_out = defobj; 4240 return (0); 4241 } 4242 return (ESRCH); 4243} 4244 4245/* 4246 * Search the chain of DAGS cointed to by the given Needed_Entry 4247 * for a symbol of the given name. Each DAG is scanned completely 4248 * before advancing to the next one. Returns a pointer to the symbol, 4249 * or NULL if no definition was found. 4250 */ 4251static int 4252symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4253{ 4254 const Elf_Sym *def; 4255 const Needed_Entry *n; 4256 const Obj_Entry *defobj; 4257 SymLook req1; 4258 int res; 4259 4260 def = NULL; 4261 defobj = NULL; 4262 symlook_init_from_req(&req1, req); 4263 for (n = needed; n != NULL; n = n->next) { 4264 if (n->obj == NULL || 4265 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4266 continue; 4267 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4268 def = req1.sym_out; 4269 defobj = req1.defobj_out; 4270 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4271 break; 4272 } 4273 } 4274 if (def != NULL) { 4275 req->sym_out = def; 4276 req->defobj_out = defobj; 4277 return (0); 4278 } 4279 return (ESRCH); 4280} 4281 4282/* 4283 * Search the symbol table of a single shared object for a symbol of 4284 * the given name and version, if requested. Returns a pointer to the 4285 * symbol, or NULL if no definition was found. If the object is 4286 * filter, return filtered symbol from filtee. 4287 * 4288 * The symbol's hash value is passed in for efficiency reasons; that 4289 * eliminates many recomputations of the hash value. 4290 */ 4291int 4292symlook_obj(SymLook *req, const Obj_Entry *obj) 4293{ 4294 DoneList donelist; 4295 SymLook req1; 4296 int flags, res, mres; 4297 4298 /* 4299 * If there is at least one valid hash at this point, we prefer to 4300 * use the faster GNU version if available. 4301 */ 4302 if (obj->valid_hash_gnu) 4303 mres = symlook_obj1_gnu(req, obj); 4304 else if (obj->valid_hash_sysv) 4305 mres = symlook_obj1_sysv(req, obj); 4306 else 4307 return (EINVAL); 4308 4309 if (mres == 0) { 4310 if (obj->needed_filtees != NULL) { 4311 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4312 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4313 donelist_init(&donelist); 4314 symlook_init_from_req(&req1, req); 4315 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4316 if (res == 0) { 4317 req->sym_out = req1.sym_out; 4318 req->defobj_out = req1.defobj_out; 4319 } 4320 return (res); 4321 } 4322 if (obj->needed_aux_filtees != NULL) { 4323 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4324 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4325 donelist_init(&donelist); 4326 symlook_init_from_req(&req1, req); 4327 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4328 if (res == 0) { 4329 req->sym_out = req1.sym_out; 4330 req->defobj_out = req1.defobj_out; 4331 return (res); 4332 } 4333 } 4334 } 4335 return (mres); 4336} 4337 4338/* Symbol match routine common to both hash functions */ 4339static bool 4340matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4341 const unsigned long symnum) 4342{ 4343 Elf_Versym verndx; 4344 const Elf_Sym *symp; 4345 const char *strp; 4346 4347 symp = obj->symtab + symnum; 4348 strp = obj->strtab + symp->st_name; 4349 4350 switch (ELF_ST_TYPE(symp->st_info)) { 4351 case STT_FUNC: 4352 case STT_NOTYPE: 4353 case STT_OBJECT: 4354 case STT_COMMON: 4355 case STT_GNU_IFUNC: 4356 if (symp->st_value == 0) 4357 return (false); 4358 /* fallthrough */ 4359 case STT_TLS: 4360 if (symp->st_shndx != SHN_UNDEF) 4361 break; 4362#ifndef __mips__ 4363 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4364 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4365 break; 4366 /* fallthrough */ 4367#endif 4368 default: 4369 return (false); 4370 } 4371 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4372 return (false); 4373 4374 if (req->ventry == NULL) { 4375 if (obj->versyms != NULL) { 4376 verndx = VER_NDX(obj->versyms[symnum]); 4377 if (verndx > obj->vernum) { 4378 _rtld_error( 4379 "%s: symbol %s references wrong version %d", 4380 obj->path, obj->strtab + symnum, verndx); 4381 return (false); 4382 } 4383 /* 4384 * If we are not called from dlsym (i.e. this 4385 * is a normal relocation from unversioned 4386 * binary), accept the symbol immediately if 4387 * it happens to have first version after this 4388 * shared object became versioned. Otherwise, 4389 * if symbol is versioned and not hidden, 4390 * remember it. If it is the only symbol with 4391 * this name exported by the shared object, it 4392 * will be returned as a match by the calling 4393 * function. If symbol is global (verndx < 2) 4394 * accept it unconditionally. 4395 */ 4396 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4397 verndx == VER_NDX_GIVEN) { 4398 result->sym_out = symp; 4399 return (true); 4400 } 4401 else if (verndx >= VER_NDX_GIVEN) { 4402 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4403 == 0) { 4404 if (result->vsymp == NULL) 4405 result->vsymp = symp; 4406 result->vcount++; 4407 } 4408 return (false); 4409 } 4410 } 4411 result->sym_out = symp; 4412 return (true); 4413 } 4414 if (obj->versyms == NULL) { 4415 if (object_match_name(obj, req->ventry->name)) { 4416 _rtld_error("%s: object %s should provide version %s " 4417 "for symbol %s", obj_rtld.path, obj->path, 4418 req->ventry->name, obj->strtab + symnum); 4419 return (false); 4420 } 4421 } else { 4422 verndx = VER_NDX(obj->versyms[symnum]); 4423 if (verndx > obj->vernum) { 4424 _rtld_error("%s: symbol %s references wrong version %d", 4425 obj->path, obj->strtab + symnum, verndx); 4426 return (false); 4427 } 4428 if (obj->vertab[verndx].hash != req->ventry->hash || 4429 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4430 /* 4431 * Version does not match. Look if this is a 4432 * global symbol and if it is not hidden. If 4433 * global symbol (verndx < 2) is available, 4434 * use it. Do not return symbol if we are 4435 * called by dlvsym, because dlvsym looks for 4436 * a specific version and default one is not 4437 * what dlvsym wants. 4438 */ 4439 if ((req->flags & SYMLOOK_DLSYM) || 4440 (verndx >= VER_NDX_GIVEN) || 4441 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4442 return (false); 4443 } 4444 } 4445 result->sym_out = symp; 4446 return (true); 4447} 4448 4449/* 4450 * Search for symbol using SysV hash function. 4451 * obj->buckets is known not to be NULL at this point; the test for this was 4452 * performed with the obj->valid_hash_sysv assignment. 4453 */ 4454static int 4455symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4456{ 4457 unsigned long symnum; 4458 Sym_Match_Result matchres; 4459 4460 matchres.sym_out = NULL; 4461 matchres.vsymp = NULL; 4462 matchres.vcount = 0; 4463 4464 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4465 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4466 if (symnum >= obj->nchains) 4467 return (ESRCH); /* Bad object */ 4468 4469 if (matched_symbol(req, obj, &matchres, symnum)) { 4470 req->sym_out = matchres.sym_out; 4471 req->defobj_out = obj; 4472 return (0); 4473 } 4474 } 4475 if (matchres.vcount == 1) { 4476 req->sym_out = matchres.vsymp; 4477 req->defobj_out = obj; 4478 return (0); 4479 } 4480 return (ESRCH); 4481} 4482 4483/* Search for symbol using GNU hash function */ 4484static int 4485symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4486{ 4487 Elf_Addr bloom_word; 4488 const Elf32_Word *hashval; 4489 Elf32_Word bucket; 4490 Sym_Match_Result matchres; 4491 unsigned int h1, h2; 4492 unsigned long symnum; 4493 4494 matchres.sym_out = NULL; 4495 matchres.vsymp = NULL; 4496 matchres.vcount = 0; 4497 4498 /* Pick right bitmask word from Bloom filter array */ 4499 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4500 obj->maskwords_bm_gnu]; 4501 4502 /* Calculate modulus word size of gnu hash and its derivative */ 4503 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4504 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4505 4506 /* Filter out the "definitely not in set" queries */ 4507 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4508 return (ESRCH); 4509 4510 /* Locate hash chain and corresponding value element*/ 4511 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4512 if (bucket == 0) 4513 return (ESRCH); 4514 hashval = &obj->chain_zero_gnu[bucket]; 4515 do { 4516 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4517 symnum = hashval - obj->chain_zero_gnu; 4518 if (matched_symbol(req, obj, &matchres, symnum)) { 4519 req->sym_out = matchres.sym_out; 4520 req->defobj_out = obj; 4521 return (0); 4522 } 4523 } 4524 } while ((*hashval++ & 1) == 0); 4525 if (matchres.vcount == 1) { 4526 req->sym_out = matchres.vsymp; 4527 req->defobj_out = obj; 4528 return (0); 4529 } 4530 return (ESRCH); 4531} 4532 4533static void 4534trace_loaded_objects(Obj_Entry *obj) 4535{ 4536 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4537 int c; 4538 4539 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4540 main_local = ""; 4541 4542 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4543 fmt1 = "\t%o => %p (%x)\n"; 4544 4545 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4546 fmt2 = "\t%o (%x)\n"; 4547 4548 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4549 4550 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4551 Needed_Entry *needed; 4552 char *name, *path; 4553 bool is_lib; 4554 4555 if (obj->marker) 4556 continue; 4557 if (list_containers && obj->needed != NULL) 4558 rtld_printf("%s:\n", obj->path); 4559 for (needed = obj->needed; needed; needed = needed->next) { 4560 if (needed->obj != NULL) { 4561 if (needed->obj->traced && !list_containers) 4562 continue; 4563 needed->obj->traced = true; 4564 path = needed->obj->path; 4565 } else 4566 path = "not found"; 4567 4568 name = (char *)obj->strtab + needed->name; 4569 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4570 4571 fmt = is_lib ? fmt1 : fmt2; 4572 while ((c = *fmt++) != '\0') { 4573 switch (c) { 4574 default: 4575 rtld_putchar(c); 4576 continue; 4577 case '\\': 4578 switch (c = *fmt) { 4579 case '\0': 4580 continue; 4581 case 'n': 4582 rtld_putchar('\n'); 4583 break; 4584 case 't': 4585 rtld_putchar('\t'); 4586 break; 4587 } 4588 break; 4589 case '%': 4590 switch (c = *fmt) { 4591 case '\0': 4592 continue; 4593 case '%': 4594 default: 4595 rtld_putchar(c); 4596 break; 4597 case 'A': 4598 rtld_putstr(main_local); 4599 break; 4600 case 'a': 4601 rtld_putstr(obj_main->path); 4602 break; 4603 case 'o': 4604 rtld_putstr(name); 4605 break; 4606#if 0 4607 case 'm': 4608 rtld_printf("%d", sodp->sod_major); 4609 break; 4610 case 'n': 4611 rtld_printf("%d", sodp->sod_minor); 4612 break; 4613#endif 4614 case 'p': 4615 rtld_putstr(path); 4616 break; 4617 case 'x': 4618 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4619 0); 4620 break; 4621 } 4622 break; 4623 } 4624 ++fmt; 4625 } 4626 } 4627 } 4628} 4629 4630/* 4631 * Unload a dlopened object and its dependencies from memory and from 4632 * our data structures. It is assumed that the DAG rooted in the 4633 * object has already been unreferenced, and that the object has a 4634 * reference count of 0. 4635 */ 4636static void 4637unload_object(Obj_Entry *root, RtldLockState *lockstate) 4638{ 4639 Obj_Entry marker, *obj, *next; 4640 4641 assert(root->refcount == 0); 4642 4643 /* 4644 * Pass over the DAG removing unreferenced objects from 4645 * appropriate lists. 4646 */ 4647 unlink_object(root); 4648 4649 /* Unmap all objects that are no longer referenced. */ 4650 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { 4651 next = TAILQ_NEXT(obj, next); 4652 if (obj->marker || obj->refcount != 0) 4653 continue; 4654 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4655 obj->mapsize, 0, obj->path); 4656 dbg("unloading \"%s\"", obj->path); 4657 /* 4658 * Unlink the object now to prevent new references from 4659 * being acquired while the bind lock is dropped in 4660 * recursive dlclose() invocations. 4661 */ 4662 TAILQ_REMOVE(&obj_list, obj, next); 4663 obj_count--; 4664 4665 if (obj->filtees_loaded) { 4666 if (next != NULL) { 4667 init_marker(&marker); 4668 TAILQ_INSERT_BEFORE(next, &marker, next); 4669 unload_filtees(obj, lockstate); 4670 next = TAILQ_NEXT(&marker, next); 4671 TAILQ_REMOVE(&obj_list, &marker, next); 4672 } else 4673 unload_filtees(obj, lockstate); 4674 } 4675 release_object(obj); 4676 } 4677} 4678 4679static void 4680unlink_object(Obj_Entry *root) 4681{ 4682 Objlist_Entry *elm; 4683 4684 if (root->refcount == 0) { 4685 /* Remove the object from the RTLD_GLOBAL list. */ 4686 objlist_remove(&list_global, root); 4687 4688 /* Remove the object from all objects' DAG lists. */ 4689 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4690 objlist_remove(&elm->obj->dldags, root); 4691 if (elm->obj != root) 4692 unlink_object(elm->obj); 4693 } 4694 } 4695} 4696 4697static void 4698ref_dag(Obj_Entry *root) 4699{ 4700 Objlist_Entry *elm; 4701 4702 assert(root->dag_inited); 4703 STAILQ_FOREACH(elm, &root->dagmembers, link) 4704 elm->obj->refcount++; 4705} 4706 4707static void 4708unref_dag(Obj_Entry *root) 4709{ 4710 Objlist_Entry *elm; 4711 4712 assert(root->dag_inited); 4713 STAILQ_FOREACH(elm, &root->dagmembers, link) 4714 elm->obj->refcount--; 4715} 4716 4717/* 4718 * Common code for MD __tls_get_addr(). 4719 */ 4720static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4721static void * 4722tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4723{ 4724 Elf_Addr *newdtv, *dtv; 4725 RtldLockState lockstate; 4726 int to_copy; 4727 4728 dtv = *dtvp; 4729 /* Check dtv generation in case new modules have arrived */ 4730 if (dtv[0] != tls_dtv_generation) { 4731 wlock_acquire(rtld_bind_lock, &lockstate); 4732 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4733 to_copy = dtv[1]; 4734 if (to_copy > tls_max_index) 4735 to_copy = tls_max_index; 4736 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4737 newdtv[0] = tls_dtv_generation; 4738 newdtv[1] = tls_max_index; 4739 free(dtv); 4740 lock_release(rtld_bind_lock, &lockstate); 4741 dtv = *dtvp = newdtv; 4742 } 4743 4744 /* Dynamically allocate module TLS if necessary */ 4745 if (dtv[index + 1] == 0) { 4746 /* Signal safe, wlock will block out signals. */ 4747 wlock_acquire(rtld_bind_lock, &lockstate); 4748 if (!dtv[index + 1]) 4749 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4750 lock_release(rtld_bind_lock, &lockstate); 4751 } 4752 return ((void *)(dtv[index + 1] + offset)); 4753} 4754 4755void * 4756tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4757{ 4758 Elf_Addr *dtv; 4759 4760 dtv = *dtvp; 4761 /* Check dtv generation in case new modules have arrived */ 4762 if (__predict_true(dtv[0] == tls_dtv_generation && 4763 dtv[index + 1] != 0)) 4764 return ((void *)(dtv[index + 1] + offset)); 4765 return (tls_get_addr_slow(dtvp, index, offset)); 4766} 4767 4768#if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4769 defined(__powerpc__) || defined(__riscv__) 4770 4771/* 4772 * Allocate Static TLS using the Variant I method. 4773 */ 4774void * 4775allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4776{ 4777 Obj_Entry *obj; 4778 char *tcb; 4779 Elf_Addr **tls; 4780 Elf_Addr *dtv; 4781 Elf_Addr addr; 4782 int i; 4783 4784 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4785 return (oldtcb); 4786 4787 assert(tcbsize >= TLS_TCB_SIZE); 4788 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4789 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4790 4791 if (oldtcb != NULL) { 4792 memcpy(tls, oldtcb, tls_static_space); 4793 free(oldtcb); 4794 4795 /* Adjust the DTV. */ 4796 dtv = tls[0]; 4797 for (i = 0; i < dtv[1]; i++) { 4798 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4799 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4800 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4801 } 4802 } 4803 } else { 4804 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4805 tls[0] = dtv; 4806 dtv[0] = tls_dtv_generation; 4807 dtv[1] = tls_max_index; 4808 4809 for (obj = globallist_curr(objs); obj != NULL; 4810 obj = globallist_next(obj)) { 4811 if (obj->tlsoffset > 0) { 4812 addr = (Elf_Addr)tls + obj->tlsoffset; 4813 if (obj->tlsinitsize > 0) 4814 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4815 if (obj->tlssize > obj->tlsinitsize) 4816 memset((void*) (addr + obj->tlsinitsize), 0, 4817 obj->tlssize - obj->tlsinitsize); 4818 dtv[obj->tlsindex + 1] = addr; 4819 } 4820 } 4821 } 4822 4823 return (tcb); 4824} 4825 4826void 4827free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4828{ 4829 Elf_Addr *dtv; 4830 Elf_Addr tlsstart, tlsend; 4831 int dtvsize, i; 4832 4833 assert(tcbsize >= TLS_TCB_SIZE); 4834 4835 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4836 tlsend = tlsstart + tls_static_space; 4837 4838 dtv = *(Elf_Addr **)tlsstart; 4839 dtvsize = dtv[1]; 4840 for (i = 0; i < dtvsize; i++) { 4841 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4842 free((void*)dtv[i+2]); 4843 } 4844 } 4845 free(dtv); 4846 free(tcb); 4847} 4848 4849#endif 4850 4851#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4852 4853/* 4854 * Allocate Static TLS using the Variant II method. 4855 */ 4856void * 4857allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4858{ 4859 Obj_Entry *obj; 4860 size_t size, ralign; 4861 char *tls; 4862 Elf_Addr *dtv, *olddtv; 4863 Elf_Addr segbase, oldsegbase, addr; 4864 int i; 4865 4866 ralign = tcbalign; 4867 if (tls_static_max_align > ralign) 4868 ralign = tls_static_max_align; 4869 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4870 4871 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4872 tls = malloc_aligned(size, ralign); 4873 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4874 4875 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4876 ((Elf_Addr*)segbase)[0] = segbase; 4877 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4878 4879 dtv[0] = tls_dtv_generation; 4880 dtv[1] = tls_max_index; 4881 4882 if (oldtls) { 4883 /* 4884 * Copy the static TLS block over whole. 4885 */ 4886 oldsegbase = (Elf_Addr) oldtls; 4887 memcpy((void *)(segbase - tls_static_space), 4888 (const void *)(oldsegbase - tls_static_space), 4889 tls_static_space); 4890 4891 /* 4892 * If any dynamic TLS blocks have been created tls_get_addr(), 4893 * move them over. 4894 */ 4895 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4896 for (i = 0; i < olddtv[1]; i++) { 4897 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4898 dtv[i+2] = olddtv[i+2]; 4899 olddtv[i+2] = 0; 4900 } 4901 } 4902 4903 /* 4904 * We assume that this block was the one we created with 4905 * allocate_initial_tls(). 4906 */ 4907 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4908 } else { 4909 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4910 if (obj->marker || obj->tlsoffset == 0) 4911 continue; 4912 addr = segbase - obj->tlsoffset; 4913 memset((void*) (addr + obj->tlsinitsize), 4914 0, obj->tlssize - obj->tlsinitsize); 4915 if (obj->tlsinit) { 4916 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4917 obj->static_tls_copied = true; 4918 } 4919 dtv[obj->tlsindex + 1] = addr; 4920 } 4921 } 4922 4923 return (void*) segbase; 4924} 4925 4926void 4927free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4928{ 4929 Elf_Addr* dtv; 4930 size_t size, ralign; 4931 int dtvsize, i; 4932 Elf_Addr tlsstart, tlsend; 4933 4934 /* 4935 * Figure out the size of the initial TLS block so that we can 4936 * find stuff which ___tls_get_addr() allocated dynamically. 4937 */ 4938 ralign = tcbalign; 4939 if (tls_static_max_align > ralign) 4940 ralign = tls_static_max_align; 4941 size = round(tls_static_space, ralign); 4942 4943 dtv = ((Elf_Addr**)tls)[1]; 4944 dtvsize = dtv[1]; 4945 tlsend = (Elf_Addr) tls; 4946 tlsstart = tlsend - size; 4947 for (i = 0; i < dtvsize; i++) { 4948 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4949 free_aligned((void *)dtv[i + 2]); 4950 } 4951 } 4952 4953 free_aligned((void *)tlsstart); 4954 free((void*) dtv); 4955} 4956 4957#endif 4958 4959/* 4960 * Allocate TLS block for module with given index. 4961 */ 4962void * 4963allocate_module_tls(int index) 4964{ 4965 Obj_Entry* obj; 4966 char* p; 4967 4968 TAILQ_FOREACH(obj, &obj_list, next) { 4969 if (obj->marker) 4970 continue; 4971 if (obj->tlsindex == index) 4972 break; 4973 } 4974 if (!obj) { 4975 _rtld_error("Can't find module with TLS index %d", index); 4976 rtld_die(); 4977 } 4978 4979 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4980 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4981 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4982 4983 return p; 4984} 4985 4986bool 4987allocate_tls_offset(Obj_Entry *obj) 4988{ 4989 size_t off; 4990 4991 if (obj->tls_done) 4992 return true; 4993 4994 if (obj->tlssize == 0) { 4995 obj->tls_done = true; 4996 return true; 4997 } 4998 4999 if (tls_last_offset == 0) 5000 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 5001 else 5002 off = calculate_tls_offset(tls_last_offset, tls_last_size, 5003 obj->tlssize, obj->tlsalign); 5004 5005 /* 5006 * If we have already fixed the size of the static TLS block, we 5007 * must stay within that size. When allocating the static TLS, we 5008 * leave a small amount of space spare to be used for dynamically 5009 * loading modules which use static TLS. 5010 */ 5011 if (tls_static_space != 0) { 5012 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 5013 return false; 5014 } else if (obj->tlsalign > tls_static_max_align) { 5015 tls_static_max_align = obj->tlsalign; 5016 } 5017 5018 tls_last_offset = obj->tlsoffset = off; 5019 tls_last_size = obj->tlssize; 5020 obj->tls_done = true; 5021 5022 return true; 5023} 5024 5025void 5026free_tls_offset(Obj_Entry *obj) 5027{ 5028 5029 /* 5030 * If we were the last thing to allocate out of the static TLS 5031 * block, we give our space back to the 'allocator'. This is a 5032 * simplistic workaround to allow libGL.so.1 to be loaded and 5033 * unloaded multiple times. 5034 */ 5035 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 5036 == calculate_tls_end(tls_last_offset, tls_last_size)) { 5037 tls_last_offset -= obj->tlssize; 5038 tls_last_size = 0; 5039 } 5040} 5041 5042void * 5043_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 5044{ 5045 void *ret; 5046 RtldLockState lockstate; 5047 5048 wlock_acquire(rtld_bind_lock, &lockstate); 5049 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 5050 tcbsize, tcbalign); 5051 lock_release(rtld_bind_lock, &lockstate); 5052 return (ret); 5053} 5054 5055void 5056_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 5057{ 5058 RtldLockState lockstate; 5059 5060 wlock_acquire(rtld_bind_lock, &lockstate); 5061 free_tls(tcb, tcbsize, tcbalign); 5062 lock_release(rtld_bind_lock, &lockstate); 5063} 5064 5065static void 5066object_add_name(Obj_Entry *obj, const char *name) 5067{ 5068 Name_Entry *entry; 5069 size_t len; 5070 5071 len = strlen(name); 5072 entry = malloc(sizeof(Name_Entry) + len); 5073 5074 if (entry != NULL) { 5075 strcpy(entry->name, name); 5076 STAILQ_INSERT_TAIL(&obj->names, entry, link); 5077 } 5078} 5079 5080static int 5081object_match_name(const Obj_Entry *obj, const char *name) 5082{ 5083 Name_Entry *entry; 5084 5085 STAILQ_FOREACH(entry, &obj->names, link) { 5086 if (strcmp(name, entry->name) == 0) 5087 return (1); 5088 } 5089 return (0); 5090} 5091 5092static Obj_Entry * 5093locate_dependency(const Obj_Entry *obj, const char *name) 5094{ 5095 const Objlist_Entry *entry; 5096 const Needed_Entry *needed; 5097 5098 STAILQ_FOREACH(entry, &list_main, link) { 5099 if (object_match_name(entry->obj, name)) 5100 return entry->obj; 5101 } 5102 5103 for (needed = obj->needed; needed != NULL; needed = needed->next) { 5104 if (strcmp(obj->strtab + needed->name, name) == 0 || 5105 (needed->obj != NULL && object_match_name(needed->obj, name))) { 5106 /* 5107 * If there is DT_NEEDED for the name we are looking for, 5108 * we are all set. Note that object might not be found if 5109 * dependency was not loaded yet, so the function can 5110 * return NULL here. This is expected and handled 5111 * properly by the caller. 5112 */ 5113 return (needed->obj); 5114 } 5115 } 5116 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 5117 obj->path, name); 5118 rtld_die(); 5119} 5120 5121static int 5122check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 5123 const Elf_Vernaux *vna) 5124{ 5125 const Elf_Verdef *vd; 5126 const char *vername; 5127 5128 vername = refobj->strtab + vna->vna_name; 5129 vd = depobj->verdef; 5130 if (vd == NULL) { 5131 _rtld_error("%s: version %s required by %s not defined", 5132 depobj->path, vername, refobj->path); 5133 return (-1); 5134 } 5135 for (;;) { 5136 if (vd->vd_version != VER_DEF_CURRENT) { 5137 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5138 depobj->path, vd->vd_version); 5139 return (-1); 5140 } 5141 if (vna->vna_hash == vd->vd_hash) { 5142 const Elf_Verdaux *aux = (const Elf_Verdaux *) 5143 ((char *)vd + vd->vd_aux); 5144 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 5145 return (0); 5146 } 5147 if (vd->vd_next == 0) 5148 break; 5149 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5150 } 5151 if (vna->vna_flags & VER_FLG_WEAK) 5152 return (0); 5153 _rtld_error("%s: version %s required by %s not found", 5154 depobj->path, vername, refobj->path); 5155 return (-1); 5156} 5157 5158static int 5159rtld_verify_object_versions(Obj_Entry *obj) 5160{ 5161 const Elf_Verneed *vn; 5162 const Elf_Verdef *vd; 5163 const Elf_Verdaux *vda; 5164 const Elf_Vernaux *vna; 5165 const Obj_Entry *depobj; 5166 int maxvernum, vernum; 5167 5168 if (obj->ver_checked) 5169 return (0); 5170 obj->ver_checked = true; 5171 5172 maxvernum = 0; 5173 /* 5174 * Walk over defined and required version records and figure out 5175 * max index used by any of them. Do very basic sanity checking 5176 * while there. 5177 */ 5178 vn = obj->verneed; 5179 while (vn != NULL) { 5180 if (vn->vn_version != VER_NEED_CURRENT) { 5181 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 5182 obj->path, vn->vn_version); 5183 return (-1); 5184 } 5185 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5186 for (;;) { 5187 vernum = VER_NEED_IDX(vna->vna_other); 5188 if (vernum > maxvernum) 5189 maxvernum = vernum; 5190 if (vna->vna_next == 0) 5191 break; 5192 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5193 } 5194 if (vn->vn_next == 0) 5195 break; 5196 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5197 } 5198 5199 vd = obj->verdef; 5200 while (vd != NULL) { 5201 if (vd->vd_version != VER_DEF_CURRENT) { 5202 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 5203 obj->path, vd->vd_version); 5204 return (-1); 5205 } 5206 vernum = VER_DEF_IDX(vd->vd_ndx); 5207 if (vernum > maxvernum) 5208 maxvernum = vernum; 5209 if (vd->vd_next == 0) 5210 break; 5211 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5212 } 5213 5214 if (maxvernum == 0) 5215 return (0); 5216 5217 /* 5218 * Store version information in array indexable by version index. 5219 * Verify that object version requirements are satisfied along the 5220 * way. 5221 */ 5222 obj->vernum = maxvernum + 1; 5223 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 5224 5225 vd = obj->verdef; 5226 while (vd != NULL) { 5227 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 5228 vernum = VER_DEF_IDX(vd->vd_ndx); 5229 assert(vernum <= maxvernum); 5230 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 5231 obj->vertab[vernum].hash = vd->vd_hash; 5232 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 5233 obj->vertab[vernum].file = NULL; 5234 obj->vertab[vernum].flags = 0; 5235 } 5236 if (vd->vd_next == 0) 5237 break; 5238 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 5239 } 5240 5241 vn = obj->verneed; 5242 while (vn != NULL) { 5243 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 5244 if (depobj == NULL) 5245 return (-1); 5246 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5247 for (;;) { 5248 if (check_object_provided_version(obj, depobj, vna)) 5249 return (-1); 5250 vernum = VER_NEED_IDX(vna->vna_other); 5251 assert(vernum <= maxvernum); 5252 obj->vertab[vernum].hash = vna->vna_hash; 5253 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5254 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5255 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5256 VER_INFO_HIDDEN : 0; 5257 if (vna->vna_next == 0) 5258 break; 5259 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5260 } 5261 if (vn->vn_next == 0) 5262 break; 5263 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5264 } 5265 return 0; 5266} 5267 5268static int 5269rtld_verify_versions(const Objlist *objlist) 5270{ 5271 Objlist_Entry *entry; 5272 int rc; 5273 5274 rc = 0; 5275 STAILQ_FOREACH(entry, objlist, link) { 5276 /* 5277 * Skip dummy objects or objects that have their version requirements 5278 * already checked. 5279 */ 5280 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5281 continue; 5282 if (rtld_verify_object_versions(entry->obj) == -1) { 5283 rc = -1; 5284 if (ld_tracing == NULL) 5285 break; 5286 } 5287 } 5288 if (rc == 0 || ld_tracing != NULL) 5289 rc = rtld_verify_object_versions(&obj_rtld); 5290 return rc; 5291} 5292 5293const Ver_Entry * 5294fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5295{ 5296 Elf_Versym vernum; 5297 5298 if (obj->vertab) { 5299 vernum = VER_NDX(obj->versyms[symnum]); 5300 if (vernum >= obj->vernum) { 5301 _rtld_error("%s: symbol %s has wrong verneed value %d", 5302 obj->path, obj->strtab + symnum, vernum); 5303 } else if (obj->vertab[vernum].hash != 0) { 5304 return &obj->vertab[vernum]; 5305 } 5306 } 5307 return NULL; 5308} 5309 5310int 5311_rtld_get_stack_prot(void) 5312{ 5313 5314 return (stack_prot); 5315} 5316 5317int 5318_rtld_is_dlopened(void *arg) 5319{ 5320 Obj_Entry *obj; 5321 RtldLockState lockstate; 5322 int res; 5323 5324 rlock_acquire(rtld_bind_lock, &lockstate); 5325 obj = dlcheck(arg); 5326 if (obj == NULL) 5327 obj = obj_from_addr(arg); 5328 if (obj == NULL) { 5329 _rtld_error("No shared object contains address"); 5330 lock_release(rtld_bind_lock, &lockstate); 5331 return (-1); 5332 } 5333 res = obj->dlopened ? 1 : 0; 5334 lock_release(rtld_bind_lock, &lockstate); 5335 return (res); 5336} 5337 5338static int 5339obj_remap_relro(Obj_Entry *obj, int prot) 5340{ 5341 5342 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5343 prot) == -1) { 5344 _rtld_error("%s: Cannot set relro protection to %#x: %s", 5345 obj->path, prot, rtld_strerror(errno)); 5346 return (-1); 5347 } 5348 return (0); 5349} 5350 5351static int 5352obj_disable_relro(Obj_Entry *obj) 5353{ 5354 5355 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); 5356} 5357 5358static int 5359obj_enforce_relro(Obj_Entry *obj) 5360{ 5361 5362 return (obj_remap_relro(obj, PROT_READ)); 5363} 5364 5365static void 5366map_stacks_exec(RtldLockState *lockstate) 5367{ 5368 void (*thr_map_stacks_exec)(void); 5369 5370 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5371 return; 5372 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5373 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5374 if (thr_map_stacks_exec != NULL) { 5375 stack_prot |= PROT_EXEC; 5376 thr_map_stacks_exec(); 5377 } 5378} 5379 5380static void 5381distribute_static_tls(Objlist *list, RtldLockState *lockstate) 5382{ 5383 Objlist_Entry *elm; 5384 Obj_Entry *obj; 5385 void (*distrib)(size_t, void *, size_t, size_t); 5386 5387 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t) 5388 get_program_var_addr("__pthread_distribute_static_tls", lockstate); 5389 if (distrib == NULL) 5390 return; 5391 STAILQ_FOREACH(elm, list, link) { 5392 obj = elm->obj; 5393 if (obj->marker || !obj->tls_done || obj->static_tls_copied) 5394 continue; 5395 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize, 5396 obj->tlssize); 5397 obj->static_tls_copied = true; 5398 } 5399} 5400 5401void 5402symlook_init(SymLook *dst, const char *name) 5403{ 5404 5405 bzero(dst, sizeof(*dst)); 5406 dst->name = name; 5407 dst->hash = elf_hash(name); 5408 dst->hash_gnu = gnu_hash(name); 5409} 5410 5411static void 5412symlook_init_from_req(SymLook *dst, const SymLook *src) 5413{ 5414 5415 dst->name = src->name; 5416 dst->hash = src->hash; 5417 dst->hash_gnu = src->hash_gnu; 5418 dst->ventry = src->ventry; 5419 dst->flags = src->flags; 5420 dst->defobj_out = NULL; 5421 dst->sym_out = NULL; 5422 dst->lockstate = src->lockstate; 5423} 5424 5425static int 5426open_binary_fd(const char *argv0, bool search_in_path, 5427 const char **binpath_res) 5428{ 5429 char *pathenv, *pe, *binpath; 5430 int fd; 5431 5432 if (search_in_path && strchr(argv0, '/') == NULL) { 5433 binpath = xmalloc(PATH_MAX); 5434 pathenv = getenv("PATH"); 5435 if (pathenv == NULL) { 5436 rtld_printf("-p and no PATH environment variable\n"); 5437 rtld_die(); 5438 } 5439 pathenv = strdup(pathenv); 5440 if (pathenv == NULL) { 5441 rtld_printf("Cannot allocate memory\n"); 5442 rtld_die(); 5443 } 5444 fd = -1; 5445 errno = ENOENT; 5446 while ((pe = strsep(&pathenv, ":")) != NULL) { 5447 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) 5448 continue; 5449 if (binpath[0] != '\0' && 5450 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) 5451 continue; 5452 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) 5453 continue; 5454 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); 5455 if (fd != -1 || errno != ENOENT) { 5456 *binpath_res = binpath; 5457 break; 5458 } 5459 } 5460 free(pathenv); 5461 } else { 5462 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); 5463 *binpath_res = argv0; 5464 } 5465 /* XXXKIB Use getcwd() to resolve relative binpath to absolute. */ 5466 5467 if (fd == -1) { 5468 rtld_printf("Opening %s: %s\n", argv0, 5469 rtld_strerror(errno)); 5470 rtld_die(); 5471 } 5472 return (fd); 5473} 5474 5475/* 5476 * Parse a set of command-line arguments. 5477 */ 5478static int 5479parse_args(char* argv[], int argc, bool *use_pathp, int *fdp) 5480{ 5481 const char *arg; 5482 int fd, i, j, arglen; 5483 char opt; 5484 5485 dbg("Parsing command-line arguments"); 5486 *use_pathp = false; 5487 *fdp = -1; 5488 5489 for (i = 1; i < argc; i++ ) { 5490 arg = argv[i]; 5491 dbg("argv[%d]: '%s'", i, arg); 5492 5493 /* 5494 * rtld arguments end with an explicit "--" or with the first 5495 * non-prefixed argument. 5496 */ 5497 if (strcmp(arg, "--") == 0) { 5498 i++; 5499 break; 5500 } 5501 if (arg[0] != '-') 5502 break; 5503 5504 /* 5505 * All other arguments are single-character options that can 5506 * be combined, so we need to search through `arg` for them. 5507 */ 5508 arglen = strlen(arg); 5509 for (j = 1; j < arglen; j++) { 5510 opt = arg[j]; 5511 if (opt == 'h') { 5512 print_usage(argv[0]); 5513 rtld_die(); 5514 } else if (opt == 'f') { 5515 /* 5516 * -f XX can be used to specify a descriptor for the 5517 * binary named at the command line (i.e., the later 5518 * argument will specify the process name but the 5519 * descriptor is what will actually be executed) 5520 */ 5521 if (j != arglen - 1) { 5522 /* -f must be the last option in, e.g., -abcf */ 5523 _rtld_error("invalid options: %s", arg); 5524 rtld_die(); 5525 } 5526 i++; 5527 fd = parse_integer(argv[i]); 5528 if (fd == -1) { 5529 _rtld_error("invalid file descriptor: '%s'", 5530 argv[i]); 5531 rtld_die(); 5532 } 5533 *fdp = fd; 5534 break; 5535 } else if (opt == 'p') { 5536 *use_pathp = true; 5537 } else { 5538 rtld_printf("invalid argument: '%s'\n", arg); 5539 print_usage(argv[0]); 5540 rtld_die(); 5541 } 5542 } 5543 } 5544 5545 return (i); 5546} 5547 5548/* 5549 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5550 */ 5551static int 5552parse_integer(const char *str) 5553{ 5554 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5555 const char *orig; 5556 int n; 5557 char c; 5558 5559 orig = str; 5560 n = 0; 5561 for (c = *str; c != '\0'; c = *++str) { 5562 if (c < '0' || c > '9') 5563 return (-1); 5564 5565 n *= RADIX; 5566 n += c - '0'; 5567 } 5568 5569 /* Make sure we actually parsed something. */ 5570 if (str == orig) 5571 return (-1); 5572 return (n); 5573} 5574 5575static void 5576print_usage(const char *argv0) 5577{ 5578 5579 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n" 5580 "\n" 5581 "Options:\n" 5582 " -h Display this help message\n" 5583 " -p Search in PATH for named binary\n" 5584 " -f <FD> Execute <FD> instead of searching for <binary>\n" 5585 " -- End of RTLD options\n" 5586 " <binary> Name of process to execute\n" 5587 " <args> Arguments to the executed process\n", argv0); 5588} 5589 5590/* 5591 * Overrides for libc_pic-provided functions. 5592 */ 5593 5594int 5595__getosreldate(void) 5596{ 5597 size_t len; 5598 int oid[2]; 5599 int error, osrel; 5600 5601 if (osreldate != 0) 5602 return (osreldate); 5603 5604 oid[0] = CTL_KERN; 5605 oid[1] = KERN_OSRELDATE; 5606 osrel = 0; 5607 len = sizeof(osrel); 5608 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5609 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5610 osreldate = osrel; 5611 return (osreldate); 5612} 5613 5614void 5615exit(int status) 5616{ 5617 5618 _exit(status); 5619} 5620 5621void (*__cleanup)(void); 5622int __isthreaded = 0; 5623int _thread_autoinit_dummy_decl = 1; 5624 5625/* 5626 * No unresolved symbols for rtld. 5627 */ 5628void 5629__pthread_cxa_finalize(struct dl_phdr_info *a) 5630{ 5631} 5632 5633void 5634__stack_chk_fail(void) 5635{ 5636 5637 _rtld_error("stack overflow detected; terminated"); 5638 rtld_die(); 5639} 5640__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5641 5642void 5643__chk_fail(void) 5644{ 5645 5646 _rtld_error("buffer overflow detected; terminated"); 5647 rtld_die(); 5648} 5649 5650const char * 5651rtld_strerror(int errnum) 5652{ 5653 5654 if (errnum < 0 || errnum >= sys_nerr) 5655 return ("Unknown error"); 5656 return (sys_errlist[errnum]); 5657} 5658 5659/* 5660 * No ifunc relocations. 5661 */ 5662void * 5663memset(void *dest, int c, size_t len) 5664{ 5665 size_t i; 5666 5667 for (i = 0; i < len; i++) 5668 ((char *)dest)[i] = c; 5669 return (dest); 5670} 5671 5672void 5673bzero(void *dest, size_t len) 5674{ 5675 size_t i; 5676 5677 for (i = 0; i < len; i++) 5678 ((char *)dest)[i] = 0; 5679} 5680