rtld.c revision 304456
1/*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD: releng/11.0/libexec/rtld-elf/rtld.c 304456 2016-08-19 08:44:37Z kib $ 29 */ 30 31/* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37#include <sys/param.h> 38#include <sys/mount.h> 39#include <sys/mman.h> 40#include <sys/stat.h> 41#include <sys/sysctl.h> 42#include <sys/uio.h> 43#include <sys/utsname.h> 44#include <sys/ktrace.h> 45 46#include <dlfcn.h> 47#include <err.h> 48#include <errno.h> 49#include <fcntl.h> 50#include <stdarg.h> 51#include <stdio.h> 52#include <stdlib.h> 53#include <string.h> 54#include <unistd.h> 55 56#include "debug.h" 57#include "rtld.h" 58#include "libmap.h" 59#include "paths.h" 60#include "rtld_tls.h" 61#include "rtld_printf.h" 62#include "notes.h" 63 64/* Types. */ 65typedef void (*func_ptr_type)(); 66typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 67 68/* 69 * Function declarations. 70 */ 71static const char *basename(const char *); 72static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 73 const Elf_Dyn **, const Elf_Dyn **); 74static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 75 const Elf_Dyn *); 76static void digest_dynamic(Obj_Entry *, int); 77static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 78static Obj_Entry *dlcheck(void *); 79static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 80 int lo_flags, int mode, RtldLockState *lockstate); 81static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 82static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 83static bool donelist_check(DoneList *, const Obj_Entry *); 84static void errmsg_restore(char *); 85static char *errmsg_save(void); 86static void *fill_search_info(const char *, size_t, void *); 87static char *find_library(const char *, const Obj_Entry *, int *); 88static const char *gethints(bool); 89static void init_dag(Obj_Entry *); 90static void init_pagesizes(Elf_Auxinfo **aux_info); 91static void init_rtld(caddr_t, Elf_Auxinfo **); 92static void initlist_add_neededs(Needed_Entry *, Objlist *); 93static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 94static void linkmap_add(Obj_Entry *); 95static void linkmap_delete(Obj_Entry *); 96static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 97static void unload_filtees(Obj_Entry *); 98static int load_needed_objects(Obj_Entry *, int); 99static int load_preload_objects(void); 100static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 101static void map_stacks_exec(RtldLockState *); 102static Obj_Entry *obj_from_addr(const void *); 103static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 104static void objlist_call_init(Objlist *, RtldLockState *); 105static void objlist_clear(Objlist *); 106static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 107static void objlist_init(Objlist *); 108static void objlist_push_head(Objlist *, Obj_Entry *); 109static void objlist_push_tail(Objlist *, Obj_Entry *); 110static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 111static void objlist_remove(Objlist *, Obj_Entry *); 112static int parse_libdir(const char *); 113static void *path_enumerate(const char *, path_enum_proc, void *); 114static int relocate_object_dag(Obj_Entry *root, bool bind_now, 115 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 116static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 117 int flags, RtldLockState *lockstate); 118static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 119 RtldLockState *); 120static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 121 int flags, RtldLockState *lockstate); 122static int rtld_dirname(const char *, char *); 123static int rtld_dirname_abs(const char *, char *); 124static void *rtld_dlopen(const char *name, int fd, int mode); 125static void rtld_exit(void); 126static char *search_library_path(const char *, const char *); 127static char *search_library_pathfds(const char *, const char *, int *); 128static const void **get_program_var_addr(const char *, RtldLockState *); 129static void set_program_var(const char *, const void *); 130static int symlook_default(SymLook *, const Obj_Entry *refobj); 131static int symlook_global(SymLook *, DoneList *); 132static void symlook_init_from_req(SymLook *, const SymLook *); 133static int symlook_list(SymLook *, const Objlist *, DoneList *); 134static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 135static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 136static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 137static void trace_loaded_objects(Obj_Entry *); 138static void unlink_object(Obj_Entry *); 139static void unload_object(Obj_Entry *); 140static void unref_dag(Obj_Entry *); 141static void ref_dag(Obj_Entry *); 142static char *origin_subst_one(Obj_Entry *, char *, const char *, 143 const char *, bool); 144static char *origin_subst(Obj_Entry *, char *); 145static bool obj_resolve_origin(Obj_Entry *obj); 146static void preinit_main(void); 147static int rtld_verify_versions(const Objlist *); 148static int rtld_verify_object_versions(Obj_Entry *); 149static void object_add_name(Obj_Entry *, const char *); 150static int object_match_name(const Obj_Entry *, const char *); 151static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 152static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 153 struct dl_phdr_info *phdr_info); 154static uint32_t gnu_hash(const char *); 155static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 156 const unsigned long); 157 158void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 159void _r_debug_postinit(struct link_map *) __noinline __exported; 160 161int __sys_openat(int, const char *, int, ...); 162 163/* 164 * Data declarations. 165 */ 166static char *error_message; /* Message for dlerror(), or NULL */ 167struct r_debug r_debug __exported; /* for GDB; */ 168static bool libmap_disable; /* Disable libmap */ 169static bool ld_loadfltr; /* Immediate filters processing */ 170static char *libmap_override; /* Maps to use in addition to libmap.conf */ 171static bool trust; /* False for setuid and setgid programs */ 172static bool dangerous_ld_env; /* True if environment variables have been 173 used to affect the libraries loaded */ 174static char *ld_bind_now; /* Environment variable for immediate binding */ 175static char *ld_debug; /* Environment variable for debugging */ 176static char *ld_library_path; /* Environment variable for search path */ 177static char *ld_library_dirs; /* Environment variable for library descriptors */ 178static char *ld_preload; /* Environment variable for libraries to 179 load first */ 180static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 181static char *ld_tracing; /* Called from ldd to print libs */ 182static char *ld_utrace; /* Use utrace() to log events. */ 183static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 184static Obj_Entry *obj_main; /* The main program shared object */ 185static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 186static unsigned int obj_count; /* Number of objects in obj_list */ 187static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 188 189static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 190 STAILQ_HEAD_INITIALIZER(list_global); 191static Objlist list_main = /* Objects loaded at program startup */ 192 STAILQ_HEAD_INITIALIZER(list_main); 193static Objlist list_fini = /* Objects needing fini() calls */ 194 STAILQ_HEAD_INITIALIZER(list_fini); 195 196Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 197 198#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 199 200extern Elf_Dyn _DYNAMIC; 201#pragma weak _DYNAMIC 202#ifndef RTLD_IS_DYNAMIC 203#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 204#endif 205 206int dlclose(void *) __exported; 207char *dlerror(void) __exported; 208void *dlopen(const char *, int) __exported; 209void *fdlopen(int, int) __exported; 210void *dlsym(void *, const char *) __exported; 211dlfunc_t dlfunc(void *, const char *) __exported; 212void *dlvsym(void *, const char *, const char *) __exported; 213int dladdr(const void *, Dl_info *) __exported; 214void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 215 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 216int dlinfo(void *, int , void *) __exported; 217int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 218int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 219int _rtld_get_stack_prot(void) __exported; 220int _rtld_is_dlopened(void *) __exported; 221void _rtld_error(const char *, ...) __exported; 222 223int npagesizes, osreldate; 224size_t *pagesizes; 225 226long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 227 228static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 229static int max_stack_flags; 230 231/* 232 * Global declarations normally provided by crt1. The dynamic linker is 233 * not built with crt1, so we have to provide them ourselves. 234 */ 235char *__progname; 236char **environ; 237 238/* 239 * Used to pass argc, argv to init functions. 240 */ 241int main_argc; 242char **main_argv; 243 244/* 245 * Globals to control TLS allocation. 246 */ 247size_t tls_last_offset; /* Static TLS offset of last module */ 248size_t tls_last_size; /* Static TLS size of last module */ 249size_t tls_static_space; /* Static TLS space allocated */ 250size_t tls_static_max_align; 251int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 252int tls_max_index = 1; /* Largest module index allocated */ 253 254bool ld_library_path_rpath = false; 255 256/* 257 * Globals for path names, and such 258 */ 259char *ld_elf_hints_default = _PATH_ELF_HINTS; 260char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; 261char *ld_path_rtld = _PATH_RTLD; 262char *ld_standard_library_path = STANDARD_LIBRARY_PATH; 263char *ld_env_prefix = LD_; 264 265/* 266 * Fill in a DoneList with an allocation large enough to hold all of 267 * the currently-loaded objects. Keep this as a macro since it calls 268 * alloca and we want that to occur within the scope of the caller. 269 */ 270#define donelist_init(dlp) \ 271 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 272 assert((dlp)->objs != NULL), \ 273 (dlp)->num_alloc = obj_count, \ 274 (dlp)->num_used = 0) 275 276#define UTRACE_DLOPEN_START 1 277#define UTRACE_DLOPEN_STOP 2 278#define UTRACE_DLCLOSE_START 3 279#define UTRACE_DLCLOSE_STOP 4 280#define UTRACE_LOAD_OBJECT 5 281#define UTRACE_UNLOAD_OBJECT 6 282#define UTRACE_ADD_RUNDEP 7 283#define UTRACE_PRELOAD_FINISHED 8 284#define UTRACE_INIT_CALL 9 285#define UTRACE_FINI_CALL 10 286#define UTRACE_DLSYM_START 11 287#define UTRACE_DLSYM_STOP 12 288 289struct utrace_rtld { 290 char sig[4]; /* 'RTLD' */ 291 int event; 292 void *handle; 293 void *mapbase; /* Used for 'parent' and 'init/fini' */ 294 size_t mapsize; 295 int refcnt; /* Used for 'mode' */ 296 char name[MAXPATHLEN]; 297}; 298 299#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 300 if (ld_utrace != NULL) \ 301 ld_utrace_log(e, h, mb, ms, r, n); \ 302} while (0) 303 304static void 305ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 306 int refcnt, const char *name) 307{ 308 struct utrace_rtld ut; 309 310 ut.sig[0] = 'R'; 311 ut.sig[1] = 'T'; 312 ut.sig[2] = 'L'; 313 ut.sig[3] = 'D'; 314 ut.event = event; 315 ut.handle = handle; 316 ut.mapbase = mapbase; 317 ut.mapsize = mapsize; 318 ut.refcnt = refcnt; 319 bzero(ut.name, sizeof(ut.name)); 320 if (name) 321 strlcpy(ut.name, name, sizeof(ut.name)); 322 utrace(&ut, sizeof(ut)); 323} 324 325#ifdef RTLD_VARIANT_ENV_NAMES 326/* 327 * construct the env variable based on the type of binary that's 328 * running. 329 */ 330static inline const char * 331_LD(const char *var) 332{ 333 static char buffer[128]; 334 335 strlcpy(buffer, ld_env_prefix, sizeof(buffer)); 336 strlcat(buffer, var, sizeof(buffer)); 337 return (buffer); 338} 339#else 340#define _LD(x) LD_ x 341#endif 342 343/* 344 * Main entry point for dynamic linking. The first argument is the 345 * stack pointer. The stack is expected to be laid out as described 346 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 347 * Specifically, the stack pointer points to a word containing 348 * ARGC. Following that in the stack is a null-terminated sequence 349 * of pointers to argument strings. Then comes a null-terminated 350 * sequence of pointers to environment strings. Finally, there is a 351 * sequence of "auxiliary vector" entries. 352 * 353 * The second argument points to a place to store the dynamic linker's 354 * exit procedure pointer and the third to a place to store the main 355 * program's object. 356 * 357 * The return value is the main program's entry point. 358 */ 359func_ptr_type 360_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 361{ 362 Elf_Auxinfo *aux_info[AT_COUNT]; 363 int i; 364 int argc; 365 char **argv; 366 char **env; 367 Elf_Auxinfo *aux; 368 Elf_Auxinfo *auxp; 369 const char *argv0; 370 Objlist_Entry *entry; 371 Obj_Entry *obj; 372 Obj_Entry *preload_tail; 373 Obj_Entry *last_interposer; 374 Objlist initlist; 375 RtldLockState lockstate; 376 char *library_path_rpath; 377 int mib[2]; 378 size_t len; 379 380 /* 381 * On entry, the dynamic linker itself has not been relocated yet. 382 * Be very careful not to reference any global data until after 383 * init_rtld has returned. It is OK to reference file-scope statics 384 * and string constants, and to call static and global functions. 385 */ 386 387 /* Find the auxiliary vector on the stack. */ 388 argc = *sp++; 389 argv = (char **) sp; 390 sp += argc + 1; /* Skip over arguments and NULL terminator */ 391 env = (char **) sp; 392 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 393 ; 394 aux = (Elf_Auxinfo *) sp; 395 396 /* Digest the auxiliary vector. */ 397 for (i = 0; i < AT_COUNT; i++) 398 aux_info[i] = NULL; 399 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 400 if (auxp->a_type < AT_COUNT) 401 aux_info[auxp->a_type] = auxp; 402 } 403 404 /* Initialize and relocate ourselves. */ 405 assert(aux_info[AT_BASE] != NULL); 406 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 407 408 __progname = obj_rtld.path; 409 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 410 environ = env; 411 main_argc = argc; 412 main_argv = argv; 413 414 if (aux_info[AT_CANARY] != NULL && 415 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 416 i = aux_info[AT_CANARYLEN]->a_un.a_val; 417 if (i > sizeof(__stack_chk_guard)) 418 i = sizeof(__stack_chk_guard); 419 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 420 } else { 421 mib[0] = CTL_KERN; 422 mib[1] = KERN_ARND; 423 424 len = sizeof(__stack_chk_guard); 425 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 426 len != sizeof(__stack_chk_guard)) { 427 /* If sysctl was unsuccessful, use the "terminator canary". */ 428 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 429 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 430 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 431 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 432 } 433 } 434 435 trust = !issetugid(); 436 437 md_abi_variant_hook(aux_info); 438 439 ld_bind_now = getenv(_LD("BIND_NOW")); 440 /* 441 * If the process is tainted, then we un-set the dangerous environment 442 * variables. The process will be marked as tainted until setuid(2) 443 * is called. If any child process calls setuid(2) we do not want any 444 * future processes to honor the potentially un-safe variables. 445 */ 446 if (!trust) { 447 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) || 448 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) || 449 unsetenv(_LD("LIBMAP_DISABLE")) || 450 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) || 451 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) { 452 _rtld_error("environment corrupt; aborting"); 453 rtld_die(); 454 } 455 } 456 ld_debug = getenv(_LD("DEBUG")); 457 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL; 458 libmap_override = getenv(_LD("LIBMAP")); 459 ld_library_path = getenv(_LD("LIBRARY_PATH")); 460 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS")); 461 ld_preload = getenv(_LD("PRELOAD")); 462 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH")); 463 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL; 464 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH")); 465 if (library_path_rpath != NULL) { 466 if (library_path_rpath[0] == 'y' || 467 library_path_rpath[0] == 'Y' || 468 library_path_rpath[0] == '1') 469 ld_library_path_rpath = true; 470 else 471 ld_library_path_rpath = false; 472 } 473 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 474 (ld_library_path != NULL) || (ld_preload != NULL) || 475 (ld_elf_hints_path != NULL) || ld_loadfltr; 476 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS")); 477 ld_utrace = getenv(_LD("UTRACE")); 478 479 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 480 ld_elf_hints_path = ld_elf_hints_default; 481 482 if (ld_debug != NULL && *ld_debug != '\0') 483 debug = 1; 484 dbg("%s is initialized, base address = %p", __progname, 485 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 486 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 487 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 488 489 dbg("initializing thread locks"); 490 lockdflt_init(); 491 492 /* 493 * Load the main program, or process its program header if it is 494 * already loaded. 495 */ 496 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 497 int fd = aux_info[AT_EXECFD]->a_un.a_val; 498 dbg("loading main program"); 499 obj_main = map_object(fd, argv0, NULL); 500 close(fd); 501 if (obj_main == NULL) 502 rtld_die(); 503 max_stack_flags = obj->stack_flags; 504 } else { /* Main program already loaded. */ 505 const Elf_Phdr *phdr; 506 int phnum; 507 caddr_t entry; 508 509 dbg("processing main program's program header"); 510 assert(aux_info[AT_PHDR] != NULL); 511 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 512 assert(aux_info[AT_PHNUM] != NULL); 513 phnum = aux_info[AT_PHNUM]->a_un.a_val; 514 assert(aux_info[AT_PHENT] != NULL); 515 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 516 assert(aux_info[AT_ENTRY] != NULL); 517 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 518 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 519 rtld_die(); 520 } 521 522 if (aux_info[AT_EXECPATH] != NULL) { 523 char *kexecpath; 524 char buf[MAXPATHLEN]; 525 526 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 527 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 528 if (kexecpath[0] == '/') 529 obj_main->path = kexecpath; 530 else if (getcwd(buf, sizeof(buf)) == NULL || 531 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 532 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 533 obj_main->path = xstrdup(argv0); 534 else 535 obj_main->path = xstrdup(buf); 536 } else { 537 dbg("No AT_EXECPATH"); 538 obj_main->path = xstrdup(argv0); 539 } 540 dbg("obj_main path %s", obj_main->path); 541 obj_main->mainprog = true; 542 543 if (aux_info[AT_STACKPROT] != NULL && 544 aux_info[AT_STACKPROT]->a_un.a_val != 0) 545 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 546 547#ifndef COMPAT_32BIT 548 /* 549 * Get the actual dynamic linker pathname from the executable if 550 * possible. (It should always be possible.) That ensures that 551 * gdb will find the right dynamic linker even if a non-standard 552 * one is being used. 553 */ 554 if (obj_main->interp != NULL && 555 strcmp(obj_main->interp, obj_rtld.path) != 0) { 556 free(obj_rtld.path); 557 obj_rtld.path = xstrdup(obj_main->interp); 558 __progname = obj_rtld.path; 559 } 560#endif 561 562 digest_dynamic(obj_main, 0); 563 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 564 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 565 obj_main->dynsymcount); 566 567 linkmap_add(obj_main); 568 linkmap_add(&obj_rtld); 569 570 /* Link the main program into the list of objects. */ 571 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 572 obj_count++; 573 obj_loads++; 574 575 /* Initialize a fake symbol for resolving undefined weak references. */ 576 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 577 sym_zero.st_shndx = SHN_UNDEF; 578 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 579 580 if (!libmap_disable) 581 libmap_disable = (bool)lm_init(libmap_override); 582 583 dbg("loading LD_PRELOAD libraries"); 584 if (load_preload_objects() == -1) 585 rtld_die(); 586 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 587 588 dbg("loading needed objects"); 589 if (load_needed_objects(obj_main, 0) == -1) 590 rtld_die(); 591 592 /* Make a list of all objects loaded at startup. */ 593 last_interposer = obj_main; 594 TAILQ_FOREACH(obj, &obj_list, next) { 595 if (obj->marker) 596 continue; 597 if (obj->z_interpose && obj != obj_main) { 598 objlist_put_after(&list_main, last_interposer, obj); 599 last_interposer = obj; 600 } else { 601 objlist_push_tail(&list_main, obj); 602 } 603 obj->refcount++; 604 } 605 606 dbg("checking for required versions"); 607 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 608 rtld_die(); 609 610 if (ld_tracing) { /* We're done */ 611 trace_loaded_objects(obj_main); 612 exit(0); 613 } 614 615 if (getenv(_LD("DUMP_REL_PRE")) != NULL) { 616 dump_relocations(obj_main); 617 exit (0); 618 } 619 620 /* 621 * Processing tls relocations requires having the tls offsets 622 * initialized. Prepare offsets before starting initial 623 * relocation processing. 624 */ 625 dbg("initializing initial thread local storage offsets"); 626 STAILQ_FOREACH(entry, &list_main, link) { 627 /* 628 * Allocate all the initial objects out of the static TLS 629 * block even if they didn't ask for it. 630 */ 631 allocate_tls_offset(entry->obj); 632 } 633 634 if (relocate_objects(obj_main, 635 ld_bind_now != NULL && *ld_bind_now != '\0', 636 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 637 rtld_die(); 638 639 dbg("doing copy relocations"); 640 if (do_copy_relocations(obj_main) == -1) 641 rtld_die(); 642 643 if (getenv(_LD("DUMP_REL_POST")) != NULL) { 644 dump_relocations(obj_main); 645 exit (0); 646 } 647 648 /* 649 * Setup TLS for main thread. This must be done after the 650 * relocations are processed, since tls initialization section 651 * might be the subject for relocations. 652 */ 653 dbg("initializing initial thread local storage"); 654 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 655 656 dbg("initializing key program variables"); 657 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 658 set_program_var("environ", env); 659 set_program_var("__elf_aux_vector", aux); 660 661 /* Make a list of init functions to call. */ 662 objlist_init(&initlist); 663 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 664 preload_tail, &initlist); 665 666 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 667 668 map_stacks_exec(NULL); 669 670 dbg("resolving ifuncs"); 671 if (resolve_objects_ifunc(obj_main, 672 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 673 NULL) == -1) 674 rtld_die(); 675 676 if (!obj_main->crt_no_init) { 677 /* 678 * Make sure we don't call the main program's init and fini 679 * functions for binaries linked with old crt1 which calls 680 * _init itself. 681 */ 682 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 683 obj_main->preinit_array = obj_main->init_array = 684 obj_main->fini_array = (Elf_Addr)NULL; 685 } 686 687 wlock_acquire(rtld_bind_lock, &lockstate); 688 if (obj_main->crt_no_init) 689 preinit_main(); 690 objlist_call_init(&initlist, &lockstate); 691 _r_debug_postinit(&obj_main->linkmap); 692 objlist_clear(&initlist); 693 dbg("loading filtees"); 694 TAILQ_FOREACH(obj, &obj_list, next) { 695 if (obj->marker) 696 continue; 697 if (ld_loadfltr || obj->z_loadfltr) 698 load_filtees(obj, 0, &lockstate); 699 } 700 lock_release(rtld_bind_lock, &lockstate); 701 702 dbg("transferring control to program entry point = %p", obj_main->entry); 703 704 /* Return the exit procedure and the program entry point. */ 705 *exit_proc = rtld_exit; 706 *objp = obj_main; 707 return (func_ptr_type) obj_main->entry; 708} 709 710void * 711rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 712{ 713 void *ptr; 714 Elf_Addr target; 715 716 ptr = (void *)make_function_pointer(def, obj); 717 target = ((Elf_Addr (*)(void))ptr)(); 718 return ((void *)target); 719} 720 721Elf_Addr 722_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 723{ 724 const Elf_Rel *rel; 725 const Elf_Sym *def; 726 const Obj_Entry *defobj; 727 Elf_Addr *where; 728 Elf_Addr target; 729 RtldLockState lockstate; 730 731 rlock_acquire(rtld_bind_lock, &lockstate); 732 if (sigsetjmp(lockstate.env, 0) != 0) 733 lock_upgrade(rtld_bind_lock, &lockstate); 734 if (obj->pltrel) 735 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 736 else 737 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 738 739 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 740 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 741 &lockstate); 742 if (def == NULL) 743 rtld_die(); 744 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 745 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 746 else 747 target = (Elf_Addr)(defobj->relocbase + def->st_value); 748 749 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 750 defobj->strtab + def->st_name, basename(obj->path), 751 (void *)target, basename(defobj->path)); 752 753 /* 754 * Write the new contents for the jmpslot. Note that depending on 755 * architecture, the value which we need to return back to the 756 * lazy binding trampoline may or may not be the target 757 * address. The value returned from reloc_jmpslot() is the value 758 * that the trampoline needs. 759 */ 760 target = reloc_jmpslot(where, target, defobj, obj, rel); 761 lock_release(rtld_bind_lock, &lockstate); 762 return target; 763} 764 765/* 766 * Error reporting function. Use it like printf. If formats the message 767 * into a buffer, and sets things up so that the next call to dlerror() 768 * will return the message. 769 */ 770void 771_rtld_error(const char *fmt, ...) 772{ 773 static char buf[512]; 774 va_list ap; 775 776 va_start(ap, fmt); 777 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 778 error_message = buf; 779 va_end(ap); 780} 781 782/* 783 * Return a dynamically-allocated copy of the current error message, if any. 784 */ 785static char * 786errmsg_save(void) 787{ 788 return error_message == NULL ? NULL : xstrdup(error_message); 789} 790 791/* 792 * Restore the current error message from a copy which was previously saved 793 * by errmsg_save(). The copy is freed. 794 */ 795static void 796errmsg_restore(char *saved_msg) 797{ 798 if (saved_msg == NULL) 799 error_message = NULL; 800 else { 801 _rtld_error("%s", saved_msg); 802 free(saved_msg); 803 } 804} 805 806static const char * 807basename(const char *name) 808{ 809 const char *p = strrchr(name, '/'); 810 return p != NULL ? p + 1 : name; 811} 812 813static struct utsname uts; 814 815static char * 816origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 817 const char *subst, bool may_free) 818{ 819 char *p, *p1, *res, *resp; 820 int subst_len, kw_len, subst_count, old_len, new_len; 821 822 kw_len = strlen(kw); 823 824 /* 825 * First, count the number of the keyword occurrences, to 826 * preallocate the final string. 827 */ 828 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 829 p1 = strstr(p, kw); 830 if (p1 == NULL) 831 break; 832 } 833 834 /* 835 * If the keyword is not found, just return. 836 * 837 * Return non-substituted string if resolution failed. We 838 * cannot do anything more reasonable, the failure mode of the 839 * caller is unresolved library anyway. 840 */ 841 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 842 return (may_free ? real : xstrdup(real)); 843 if (obj != NULL) 844 subst = obj->origin_path; 845 846 /* 847 * There is indeed something to substitute. Calculate the 848 * length of the resulting string, and allocate it. 849 */ 850 subst_len = strlen(subst); 851 old_len = strlen(real); 852 new_len = old_len + (subst_len - kw_len) * subst_count; 853 res = xmalloc(new_len + 1); 854 855 /* 856 * Now, execute the substitution loop. 857 */ 858 for (p = real, resp = res, *resp = '\0';;) { 859 p1 = strstr(p, kw); 860 if (p1 != NULL) { 861 /* Copy the prefix before keyword. */ 862 memcpy(resp, p, p1 - p); 863 resp += p1 - p; 864 /* Keyword replacement. */ 865 memcpy(resp, subst, subst_len); 866 resp += subst_len; 867 *resp = '\0'; 868 p = p1 + kw_len; 869 } else 870 break; 871 } 872 873 /* Copy to the end of string and finish. */ 874 strcat(resp, p); 875 if (may_free) 876 free(real); 877 return (res); 878} 879 880static char * 881origin_subst(Obj_Entry *obj, char *real) 882{ 883 char *res1, *res2, *res3, *res4; 884 885 if (obj == NULL || !trust) 886 return (xstrdup(real)); 887 if (uts.sysname[0] == '\0') { 888 if (uname(&uts) != 0) { 889 _rtld_error("utsname failed: %d", errno); 890 return (NULL); 891 } 892 } 893 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 894 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 895 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 896 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 897 return (res4); 898} 899 900void 901rtld_die(void) 902{ 903 const char *msg = dlerror(); 904 905 if (msg == NULL) 906 msg = "Fatal error"; 907 rtld_fdputstr(STDERR_FILENO, msg); 908 rtld_fdputchar(STDERR_FILENO, '\n'); 909 _exit(1); 910} 911 912/* 913 * Process a shared object's DYNAMIC section, and save the important 914 * information in its Obj_Entry structure. 915 */ 916static void 917digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 918 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 919{ 920 const Elf_Dyn *dynp; 921 Needed_Entry **needed_tail = &obj->needed; 922 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 923 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 924 const Elf_Hashelt *hashtab; 925 const Elf32_Word *hashval; 926 Elf32_Word bkt, nmaskwords; 927 int bloom_size32; 928 int plttype = DT_REL; 929 930 *dyn_rpath = NULL; 931 *dyn_soname = NULL; 932 *dyn_runpath = NULL; 933 934 obj->bind_now = false; 935 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 936 switch (dynp->d_tag) { 937 938 case DT_REL: 939 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 940 break; 941 942 case DT_RELSZ: 943 obj->relsize = dynp->d_un.d_val; 944 break; 945 946 case DT_RELENT: 947 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 948 break; 949 950 case DT_JMPREL: 951 obj->pltrel = (const Elf_Rel *) 952 (obj->relocbase + dynp->d_un.d_ptr); 953 break; 954 955 case DT_PLTRELSZ: 956 obj->pltrelsize = dynp->d_un.d_val; 957 break; 958 959 case DT_RELA: 960 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 961 break; 962 963 case DT_RELASZ: 964 obj->relasize = dynp->d_un.d_val; 965 break; 966 967 case DT_RELAENT: 968 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 969 break; 970 971 case DT_PLTREL: 972 plttype = dynp->d_un.d_val; 973 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 974 break; 975 976 case DT_SYMTAB: 977 obj->symtab = (const Elf_Sym *) 978 (obj->relocbase + dynp->d_un.d_ptr); 979 break; 980 981 case DT_SYMENT: 982 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 983 break; 984 985 case DT_STRTAB: 986 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 987 break; 988 989 case DT_STRSZ: 990 obj->strsize = dynp->d_un.d_val; 991 break; 992 993 case DT_VERNEED: 994 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 995 dynp->d_un.d_val); 996 break; 997 998 case DT_VERNEEDNUM: 999 obj->verneednum = dynp->d_un.d_val; 1000 break; 1001 1002 case DT_VERDEF: 1003 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1004 dynp->d_un.d_val); 1005 break; 1006 1007 case DT_VERDEFNUM: 1008 obj->verdefnum = dynp->d_un.d_val; 1009 break; 1010 1011 case DT_VERSYM: 1012 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1013 dynp->d_un.d_val); 1014 break; 1015 1016 case DT_HASH: 1017 { 1018 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1019 dynp->d_un.d_ptr); 1020 obj->nbuckets = hashtab[0]; 1021 obj->nchains = hashtab[1]; 1022 obj->buckets = hashtab + 2; 1023 obj->chains = obj->buckets + obj->nbuckets; 1024 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1025 obj->buckets != NULL; 1026 } 1027 break; 1028 1029 case DT_GNU_HASH: 1030 { 1031 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1032 dynp->d_un.d_ptr); 1033 obj->nbuckets_gnu = hashtab[0]; 1034 obj->symndx_gnu = hashtab[1]; 1035 nmaskwords = hashtab[2]; 1036 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1037 obj->maskwords_bm_gnu = nmaskwords - 1; 1038 obj->shift2_gnu = hashtab[3]; 1039 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1040 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1041 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1042 obj->symndx_gnu; 1043 /* Number of bitmask words is required to be power of 2 */ 1044 obj->valid_hash_gnu = powerof2(nmaskwords) && 1045 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1046 } 1047 break; 1048 1049 case DT_NEEDED: 1050 if (!obj->rtld) { 1051 Needed_Entry *nep = NEW(Needed_Entry); 1052 nep->name = dynp->d_un.d_val; 1053 nep->obj = NULL; 1054 nep->next = NULL; 1055 1056 *needed_tail = nep; 1057 needed_tail = &nep->next; 1058 } 1059 break; 1060 1061 case DT_FILTER: 1062 if (!obj->rtld) { 1063 Needed_Entry *nep = NEW(Needed_Entry); 1064 nep->name = dynp->d_un.d_val; 1065 nep->obj = NULL; 1066 nep->next = NULL; 1067 1068 *needed_filtees_tail = nep; 1069 needed_filtees_tail = &nep->next; 1070 } 1071 break; 1072 1073 case DT_AUXILIARY: 1074 if (!obj->rtld) { 1075 Needed_Entry *nep = NEW(Needed_Entry); 1076 nep->name = dynp->d_un.d_val; 1077 nep->obj = NULL; 1078 nep->next = NULL; 1079 1080 *needed_aux_filtees_tail = nep; 1081 needed_aux_filtees_tail = &nep->next; 1082 } 1083 break; 1084 1085 case DT_PLTGOT: 1086 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1087 break; 1088 1089 case DT_TEXTREL: 1090 obj->textrel = true; 1091 break; 1092 1093 case DT_SYMBOLIC: 1094 obj->symbolic = true; 1095 break; 1096 1097 case DT_RPATH: 1098 /* 1099 * We have to wait until later to process this, because we 1100 * might not have gotten the address of the string table yet. 1101 */ 1102 *dyn_rpath = dynp; 1103 break; 1104 1105 case DT_SONAME: 1106 *dyn_soname = dynp; 1107 break; 1108 1109 case DT_RUNPATH: 1110 *dyn_runpath = dynp; 1111 break; 1112 1113 case DT_INIT: 1114 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1115 break; 1116 1117 case DT_PREINIT_ARRAY: 1118 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1119 break; 1120 1121 case DT_PREINIT_ARRAYSZ: 1122 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1123 break; 1124 1125 case DT_INIT_ARRAY: 1126 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1127 break; 1128 1129 case DT_INIT_ARRAYSZ: 1130 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1131 break; 1132 1133 case DT_FINI: 1134 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1135 break; 1136 1137 case DT_FINI_ARRAY: 1138 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1139 break; 1140 1141 case DT_FINI_ARRAYSZ: 1142 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1143 break; 1144 1145 /* 1146 * Don't process DT_DEBUG on MIPS as the dynamic section 1147 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1148 */ 1149 1150#ifndef __mips__ 1151 case DT_DEBUG: 1152 if (!early) 1153 dbg("Filling in DT_DEBUG entry"); 1154 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1155 break; 1156#endif 1157 1158 case DT_FLAGS: 1159 if (dynp->d_un.d_val & DF_ORIGIN) 1160 obj->z_origin = true; 1161 if (dynp->d_un.d_val & DF_SYMBOLIC) 1162 obj->symbolic = true; 1163 if (dynp->d_un.d_val & DF_TEXTREL) 1164 obj->textrel = true; 1165 if (dynp->d_un.d_val & DF_BIND_NOW) 1166 obj->bind_now = true; 1167 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1168 ;*/ 1169 break; 1170#ifdef __mips__ 1171 case DT_MIPS_LOCAL_GOTNO: 1172 obj->local_gotno = dynp->d_un.d_val; 1173 break; 1174 1175 case DT_MIPS_SYMTABNO: 1176 obj->symtabno = dynp->d_un.d_val; 1177 break; 1178 1179 case DT_MIPS_GOTSYM: 1180 obj->gotsym = dynp->d_un.d_val; 1181 break; 1182 1183 case DT_MIPS_RLD_MAP: 1184 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1185 break; 1186#endif 1187 1188#ifdef __powerpc64__ 1189 case DT_PPC64_GLINK: 1190 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1191 break; 1192#endif 1193 1194 case DT_FLAGS_1: 1195 if (dynp->d_un.d_val & DF_1_NOOPEN) 1196 obj->z_noopen = true; 1197 if (dynp->d_un.d_val & DF_1_ORIGIN) 1198 obj->z_origin = true; 1199 if (dynp->d_un.d_val & DF_1_GLOBAL) 1200 obj->z_global = true; 1201 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1202 obj->bind_now = true; 1203 if (dynp->d_un.d_val & DF_1_NODELETE) 1204 obj->z_nodelete = true; 1205 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1206 obj->z_loadfltr = true; 1207 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1208 obj->z_interpose = true; 1209 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1210 obj->z_nodeflib = true; 1211 break; 1212 1213 default: 1214 if (!early) { 1215 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1216 (long)dynp->d_tag); 1217 } 1218 break; 1219 } 1220 } 1221 1222 obj->traced = false; 1223 1224 if (plttype == DT_RELA) { 1225 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1226 obj->pltrel = NULL; 1227 obj->pltrelasize = obj->pltrelsize; 1228 obj->pltrelsize = 0; 1229 } 1230 1231 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1232 if (obj->valid_hash_sysv) 1233 obj->dynsymcount = obj->nchains; 1234 else if (obj->valid_hash_gnu) { 1235 obj->dynsymcount = 0; 1236 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1237 if (obj->buckets_gnu[bkt] == 0) 1238 continue; 1239 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1240 do 1241 obj->dynsymcount++; 1242 while ((*hashval++ & 1u) == 0); 1243 } 1244 obj->dynsymcount += obj->symndx_gnu; 1245 } 1246} 1247 1248static bool 1249obj_resolve_origin(Obj_Entry *obj) 1250{ 1251 1252 if (obj->origin_path != NULL) 1253 return (true); 1254 obj->origin_path = xmalloc(PATH_MAX); 1255 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1256} 1257 1258static void 1259digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1260 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1261{ 1262 1263 if (obj->z_origin && !obj_resolve_origin(obj)) 1264 rtld_die(); 1265 1266 if (dyn_runpath != NULL) { 1267 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1268 obj->runpath = origin_subst(obj, obj->runpath); 1269 } else if (dyn_rpath != NULL) { 1270 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1271 obj->rpath = origin_subst(obj, obj->rpath); 1272 } 1273 if (dyn_soname != NULL) 1274 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1275} 1276 1277static void 1278digest_dynamic(Obj_Entry *obj, int early) 1279{ 1280 const Elf_Dyn *dyn_rpath; 1281 const Elf_Dyn *dyn_soname; 1282 const Elf_Dyn *dyn_runpath; 1283 1284 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1285 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1286} 1287 1288/* 1289 * Process a shared object's program header. This is used only for the 1290 * main program, when the kernel has already loaded the main program 1291 * into memory before calling the dynamic linker. It creates and 1292 * returns an Obj_Entry structure. 1293 */ 1294static Obj_Entry * 1295digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1296{ 1297 Obj_Entry *obj; 1298 const Elf_Phdr *phlimit = phdr + phnum; 1299 const Elf_Phdr *ph; 1300 Elf_Addr note_start, note_end; 1301 int nsegs = 0; 1302 1303 obj = obj_new(); 1304 for (ph = phdr; ph < phlimit; ph++) { 1305 if (ph->p_type != PT_PHDR) 1306 continue; 1307 1308 obj->phdr = phdr; 1309 obj->phsize = ph->p_memsz; 1310 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1311 break; 1312 } 1313 1314 obj->stack_flags = PF_X | PF_R | PF_W; 1315 1316 for (ph = phdr; ph < phlimit; ph++) { 1317 switch (ph->p_type) { 1318 1319 case PT_INTERP: 1320 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1321 break; 1322 1323 case PT_LOAD: 1324 if (nsegs == 0) { /* First load segment */ 1325 obj->vaddrbase = trunc_page(ph->p_vaddr); 1326 obj->mapbase = obj->vaddrbase + obj->relocbase; 1327 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1328 obj->vaddrbase; 1329 } else { /* Last load segment */ 1330 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1331 obj->vaddrbase; 1332 } 1333 nsegs++; 1334 break; 1335 1336 case PT_DYNAMIC: 1337 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1338 break; 1339 1340 case PT_TLS: 1341 obj->tlsindex = 1; 1342 obj->tlssize = ph->p_memsz; 1343 obj->tlsalign = ph->p_align; 1344 obj->tlsinitsize = ph->p_filesz; 1345 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1346 break; 1347 1348 case PT_GNU_STACK: 1349 obj->stack_flags = ph->p_flags; 1350 break; 1351 1352 case PT_GNU_RELRO: 1353 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1354 obj->relro_size = round_page(ph->p_memsz); 1355 break; 1356 1357 case PT_NOTE: 1358 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1359 note_end = note_start + ph->p_filesz; 1360 digest_notes(obj, note_start, note_end); 1361 break; 1362 } 1363 } 1364 if (nsegs < 1) { 1365 _rtld_error("%s: too few PT_LOAD segments", path); 1366 return NULL; 1367 } 1368 1369 obj->entry = entry; 1370 return obj; 1371} 1372 1373void 1374digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1375{ 1376 const Elf_Note *note; 1377 const char *note_name; 1378 uintptr_t p; 1379 1380 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1381 note = (const Elf_Note *)((const char *)(note + 1) + 1382 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1383 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1384 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1385 note->n_descsz != sizeof(int32_t)) 1386 continue; 1387 if (note->n_type != NT_FREEBSD_ABI_TAG && 1388 note->n_type != NT_FREEBSD_NOINIT_TAG) 1389 continue; 1390 note_name = (const char *)(note + 1); 1391 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1392 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1393 continue; 1394 switch (note->n_type) { 1395 case NT_FREEBSD_ABI_TAG: 1396 /* FreeBSD osrel note */ 1397 p = (uintptr_t)(note + 1); 1398 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1399 obj->osrel = *(const int32_t *)(p); 1400 dbg("note osrel %d", obj->osrel); 1401 break; 1402 case NT_FREEBSD_NOINIT_TAG: 1403 /* FreeBSD 'crt does not call init' note */ 1404 obj->crt_no_init = true; 1405 dbg("note crt_no_init"); 1406 break; 1407 } 1408 } 1409} 1410 1411static Obj_Entry * 1412dlcheck(void *handle) 1413{ 1414 Obj_Entry *obj; 1415 1416 TAILQ_FOREACH(obj, &obj_list, next) { 1417 if (obj == (Obj_Entry *) handle) 1418 break; 1419 } 1420 1421 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1422 _rtld_error("Invalid shared object handle %p", handle); 1423 return NULL; 1424 } 1425 return obj; 1426} 1427 1428/* 1429 * If the given object is already in the donelist, return true. Otherwise 1430 * add the object to the list and return false. 1431 */ 1432static bool 1433donelist_check(DoneList *dlp, const Obj_Entry *obj) 1434{ 1435 unsigned int i; 1436 1437 for (i = 0; i < dlp->num_used; i++) 1438 if (dlp->objs[i] == obj) 1439 return true; 1440 /* 1441 * Our donelist allocation should always be sufficient. But if 1442 * our threads locking isn't working properly, more shared objects 1443 * could have been loaded since we allocated the list. That should 1444 * never happen, but we'll handle it properly just in case it does. 1445 */ 1446 if (dlp->num_used < dlp->num_alloc) 1447 dlp->objs[dlp->num_used++] = obj; 1448 return false; 1449} 1450 1451/* 1452 * Hash function for symbol table lookup. Don't even think about changing 1453 * this. It is specified by the System V ABI. 1454 */ 1455unsigned long 1456elf_hash(const char *name) 1457{ 1458 const unsigned char *p = (const unsigned char *) name; 1459 unsigned long h = 0; 1460 unsigned long g; 1461 1462 while (*p != '\0') { 1463 h = (h << 4) + *p++; 1464 if ((g = h & 0xf0000000) != 0) 1465 h ^= g >> 24; 1466 h &= ~g; 1467 } 1468 return h; 1469} 1470 1471/* 1472 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1473 * unsigned in case it's implemented with a wider type. 1474 */ 1475static uint32_t 1476gnu_hash(const char *s) 1477{ 1478 uint32_t h; 1479 unsigned char c; 1480 1481 h = 5381; 1482 for (c = *s; c != '\0'; c = *++s) 1483 h = h * 33 + c; 1484 return (h & 0xffffffff); 1485} 1486 1487 1488/* 1489 * Find the library with the given name, and return its full pathname. 1490 * The returned string is dynamically allocated. Generates an error 1491 * message and returns NULL if the library cannot be found. 1492 * 1493 * If the second argument is non-NULL, then it refers to an already- 1494 * loaded shared object, whose library search path will be searched. 1495 * 1496 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1497 * descriptor (which is close-on-exec) will be passed out via the third 1498 * argument. 1499 * 1500 * The search order is: 1501 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1502 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1503 * LD_LIBRARY_PATH 1504 * DT_RUNPATH in the referencing file 1505 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1506 * from list) 1507 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1508 * 1509 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1510 */ 1511static char * 1512find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1513{ 1514 char *pathname; 1515 char *name; 1516 bool nodeflib, objgiven; 1517 1518 objgiven = refobj != NULL; 1519 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1520 if (xname[0] != '/' && !trust) { 1521 _rtld_error("Absolute pathname required for shared object \"%s\"", 1522 xname); 1523 return NULL; 1524 } 1525 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1526 __DECONST(char *, xname))); 1527 } 1528 1529 if (libmap_disable || !objgiven || 1530 (name = lm_find(refobj->path, xname)) == NULL) 1531 name = (char *)xname; 1532 1533 dbg(" Searching for \"%s\"", name); 1534 1535 /* 1536 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1537 * back to pre-conforming behaviour if user requested so with 1538 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1539 * nodeflib. 1540 */ 1541 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1542 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1543 (refobj != NULL && 1544 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1545 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1546 (pathname = search_library_path(name, gethints(false))) != NULL || 1547 (pathname = search_library_path(name, ld_standard_library_path)) != NULL) 1548 return (pathname); 1549 } else { 1550 nodeflib = objgiven ? refobj->z_nodeflib : false; 1551 if ((objgiven && 1552 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1553 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1554 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1555 (pathname = search_library_path(name, ld_library_path)) != NULL || 1556 (objgiven && 1557 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1558 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1559 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1560 (objgiven && !nodeflib && 1561 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)) 1562 return (pathname); 1563 } 1564 1565 if (objgiven && refobj->path != NULL) { 1566 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1567 name, basename(refobj->path)); 1568 } else { 1569 _rtld_error("Shared object \"%s\" not found", name); 1570 } 1571 return NULL; 1572} 1573 1574/* 1575 * Given a symbol number in a referencing object, find the corresponding 1576 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1577 * no definition was found. Returns a pointer to the Obj_Entry of the 1578 * defining object via the reference parameter DEFOBJ_OUT. 1579 */ 1580const Elf_Sym * 1581find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1582 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1583 RtldLockState *lockstate) 1584{ 1585 const Elf_Sym *ref; 1586 const Elf_Sym *def; 1587 const Obj_Entry *defobj; 1588 SymLook req; 1589 const char *name; 1590 int res; 1591 1592 /* 1593 * If we have already found this symbol, get the information from 1594 * the cache. 1595 */ 1596 if (symnum >= refobj->dynsymcount) 1597 return NULL; /* Bad object */ 1598 if (cache != NULL && cache[symnum].sym != NULL) { 1599 *defobj_out = cache[symnum].obj; 1600 return cache[symnum].sym; 1601 } 1602 1603 ref = refobj->symtab + symnum; 1604 name = refobj->strtab + ref->st_name; 1605 def = NULL; 1606 defobj = NULL; 1607 1608 /* 1609 * We don't have to do a full scale lookup if the symbol is local. 1610 * We know it will bind to the instance in this load module; to 1611 * which we already have a pointer (ie ref). By not doing a lookup, 1612 * we not only improve performance, but it also avoids unresolvable 1613 * symbols when local symbols are not in the hash table. This has 1614 * been seen with the ia64 toolchain. 1615 */ 1616 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1617 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1618 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1619 symnum); 1620 } 1621 symlook_init(&req, name); 1622 req.flags = flags; 1623 req.ventry = fetch_ventry(refobj, symnum); 1624 req.lockstate = lockstate; 1625 res = symlook_default(&req, refobj); 1626 if (res == 0) { 1627 def = req.sym_out; 1628 defobj = req.defobj_out; 1629 } 1630 } else { 1631 def = ref; 1632 defobj = refobj; 1633 } 1634 1635 /* 1636 * If we found no definition and the reference is weak, treat the 1637 * symbol as having the value zero. 1638 */ 1639 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1640 def = &sym_zero; 1641 defobj = obj_main; 1642 } 1643 1644 if (def != NULL) { 1645 *defobj_out = defobj; 1646 /* Record the information in the cache to avoid subsequent lookups. */ 1647 if (cache != NULL) { 1648 cache[symnum].sym = def; 1649 cache[symnum].obj = defobj; 1650 } 1651 } else { 1652 if (refobj != &obj_rtld) 1653 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1654 } 1655 return def; 1656} 1657 1658/* 1659 * Return the search path from the ldconfig hints file, reading it if 1660 * necessary. If nostdlib is true, then the default search paths are 1661 * not added to result. 1662 * 1663 * Returns NULL if there are problems with the hints file, 1664 * or if the search path there is empty. 1665 */ 1666static const char * 1667gethints(bool nostdlib) 1668{ 1669 static char *hints, *filtered_path; 1670 static struct elfhints_hdr hdr; 1671 struct fill_search_info_args sargs, hargs; 1672 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1673 struct dl_serpath *SLPpath, *hintpath; 1674 char *p; 1675 struct stat hint_stat; 1676 unsigned int SLPndx, hintndx, fndx, fcount; 1677 int fd; 1678 size_t flen; 1679 uint32_t dl; 1680 bool skip; 1681 1682 /* First call, read the hints file */ 1683 if (hints == NULL) { 1684 /* Keep from trying again in case the hints file is bad. */ 1685 hints = ""; 1686 1687 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1688 return (NULL); 1689 1690 /* 1691 * Check of hdr.dirlistlen value against type limit 1692 * intends to pacify static analyzers. Further 1693 * paranoia leads to checks that dirlist is fully 1694 * contained in the file range. 1695 */ 1696 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1697 hdr.magic != ELFHINTS_MAGIC || 1698 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1699 fstat(fd, &hint_stat) == -1) { 1700cleanup1: 1701 close(fd); 1702 hdr.dirlistlen = 0; 1703 return (NULL); 1704 } 1705 dl = hdr.strtab; 1706 if (dl + hdr.dirlist < dl) 1707 goto cleanup1; 1708 dl += hdr.dirlist; 1709 if (dl + hdr.dirlistlen < dl) 1710 goto cleanup1; 1711 dl += hdr.dirlistlen; 1712 if (dl > hint_stat.st_size) 1713 goto cleanup1; 1714 p = xmalloc(hdr.dirlistlen + 1); 1715 1716 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1717 read(fd, p, hdr.dirlistlen + 1) != 1718 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1719 free(p); 1720 goto cleanup1; 1721 } 1722 hints = p; 1723 close(fd); 1724 } 1725 1726 /* 1727 * If caller agreed to receive list which includes the default 1728 * paths, we are done. Otherwise, if we still did not 1729 * calculated filtered result, do it now. 1730 */ 1731 if (!nostdlib) 1732 return (hints[0] != '\0' ? hints : NULL); 1733 if (filtered_path != NULL) 1734 goto filt_ret; 1735 1736 /* 1737 * Obtain the list of all configured search paths, and the 1738 * list of the default paths. 1739 * 1740 * First estimate the size of the results. 1741 */ 1742 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1743 smeta.dls_cnt = 0; 1744 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1745 hmeta.dls_cnt = 0; 1746 1747 sargs.request = RTLD_DI_SERINFOSIZE; 1748 sargs.serinfo = &smeta; 1749 hargs.request = RTLD_DI_SERINFOSIZE; 1750 hargs.serinfo = &hmeta; 1751 1752 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1753 path_enumerate(hints, fill_search_info, &hargs); 1754 1755 SLPinfo = xmalloc(smeta.dls_size); 1756 hintinfo = xmalloc(hmeta.dls_size); 1757 1758 /* 1759 * Next fetch both sets of paths. 1760 */ 1761 sargs.request = RTLD_DI_SERINFO; 1762 sargs.serinfo = SLPinfo; 1763 sargs.serpath = &SLPinfo->dls_serpath[0]; 1764 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1765 1766 hargs.request = RTLD_DI_SERINFO; 1767 hargs.serinfo = hintinfo; 1768 hargs.serpath = &hintinfo->dls_serpath[0]; 1769 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1770 1771 path_enumerate(ld_standard_library_path, fill_search_info, &sargs); 1772 path_enumerate(hints, fill_search_info, &hargs); 1773 1774 /* 1775 * Now calculate the difference between two sets, by excluding 1776 * standard paths from the full set. 1777 */ 1778 fndx = 0; 1779 fcount = 0; 1780 filtered_path = xmalloc(hdr.dirlistlen + 1); 1781 hintpath = &hintinfo->dls_serpath[0]; 1782 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1783 skip = false; 1784 SLPpath = &SLPinfo->dls_serpath[0]; 1785 /* 1786 * Check each standard path against current. 1787 */ 1788 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1789 /* matched, skip the path */ 1790 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1791 skip = true; 1792 break; 1793 } 1794 } 1795 if (skip) 1796 continue; 1797 /* 1798 * Not matched against any standard path, add the path 1799 * to result. Separate consequtive paths with ':'. 1800 */ 1801 if (fcount > 0) { 1802 filtered_path[fndx] = ':'; 1803 fndx++; 1804 } 1805 fcount++; 1806 flen = strlen(hintpath->dls_name); 1807 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1808 fndx += flen; 1809 } 1810 filtered_path[fndx] = '\0'; 1811 1812 free(SLPinfo); 1813 free(hintinfo); 1814 1815filt_ret: 1816 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1817} 1818 1819static void 1820init_dag(Obj_Entry *root) 1821{ 1822 const Needed_Entry *needed; 1823 const Objlist_Entry *elm; 1824 DoneList donelist; 1825 1826 if (root->dag_inited) 1827 return; 1828 donelist_init(&donelist); 1829 1830 /* Root object belongs to own DAG. */ 1831 objlist_push_tail(&root->dldags, root); 1832 objlist_push_tail(&root->dagmembers, root); 1833 donelist_check(&donelist, root); 1834 1835 /* 1836 * Add dependencies of root object to DAG in breadth order 1837 * by exploiting the fact that each new object get added 1838 * to the tail of the dagmembers list. 1839 */ 1840 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1841 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1842 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1843 continue; 1844 objlist_push_tail(&needed->obj->dldags, root); 1845 objlist_push_tail(&root->dagmembers, needed->obj); 1846 } 1847 } 1848 root->dag_inited = true; 1849} 1850 1851Obj_Entry * 1852globallist_curr(const Obj_Entry *obj) 1853{ 1854 1855 for (;;) { 1856 if (obj == NULL) 1857 return (NULL); 1858 if (!obj->marker) 1859 return (__DECONST(Obj_Entry *, obj)); 1860 obj = TAILQ_PREV(obj, obj_entry_q, next); 1861 } 1862} 1863 1864Obj_Entry * 1865globallist_next(const Obj_Entry *obj) 1866{ 1867 1868 for (;;) { 1869 obj = TAILQ_NEXT(obj, next); 1870 if (obj == NULL) 1871 return (NULL); 1872 if (!obj->marker) 1873 return (__DECONST(Obj_Entry *, obj)); 1874 } 1875} 1876 1877static void 1878process_z(Obj_Entry *root) 1879{ 1880 const Objlist_Entry *elm; 1881 Obj_Entry *obj; 1882 1883 /* 1884 * Walk over object DAG and process every dependent object 1885 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1886 * to grow their own DAG. 1887 * 1888 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1889 * symlook_global() to work. 1890 * 1891 * For DF_1_NODELETE, the DAG should have its reference upped. 1892 */ 1893 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1894 obj = elm->obj; 1895 if (obj == NULL) 1896 continue; 1897 if (obj->z_nodelete && !obj->ref_nodel) { 1898 dbg("obj %s -z nodelete", obj->path); 1899 init_dag(obj); 1900 ref_dag(obj); 1901 obj->ref_nodel = true; 1902 } 1903 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1904 dbg("obj %s -z global", obj->path); 1905 objlist_push_tail(&list_global, obj); 1906 init_dag(obj); 1907 } 1908 } 1909} 1910/* 1911 * Initialize the dynamic linker. The argument is the address at which 1912 * the dynamic linker has been mapped into memory. The primary task of 1913 * this function is to relocate the dynamic linker. 1914 */ 1915static void 1916init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1917{ 1918 Obj_Entry objtmp; /* Temporary rtld object */ 1919 const Elf_Ehdr *ehdr; 1920 const Elf_Dyn *dyn_rpath; 1921 const Elf_Dyn *dyn_soname; 1922 const Elf_Dyn *dyn_runpath; 1923 1924#ifdef RTLD_INIT_PAGESIZES_EARLY 1925 /* The page size is required by the dynamic memory allocator. */ 1926 init_pagesizes(aux_info); 1927#endif 1928 1929 /* 1930 * Conjure up an Obj_Entry structure for the dynamic linker. 1931 * 1932 * The "path" member can't be initialized yet because string constants 1933 * cannot yet be accessed. Below we will set it correctly. 1934 */ 1935 memset(&objtmp, 0, sizeof(objtmp)); 1936 objtmp.path = NULL; 1937 objtmp.rtld = true; 1938 objtmp.mapbase = mapbase; 1939#ifdef PIC 1940 objtmp.relocbase = mapbase; 1941#endif 1942 if (RTLD_IS_DYNAMIC()) { 1943 objtmp.dynamic = rtld_dynamic(&objtmp); 1944 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1945 assert(objtmp.needed == NULL); 1946#if !defined(__mips__) 1947 /* MIPS has a bogus DT_TEXTREL. */ 1948 assert(!objtmp.textrel); 1949#endif 1950 1951 /* 1952 * Temporarily put the dynamic linker entry into the object list, so 1953 * that symbols can be found. 1954 */ 1955 1956 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1957 } 1958 ehdr = (Elf_Ehdr *)mapbase; 1959 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1960 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1961 1962 /* Initialize the object list. */ 1963 TAILQ_INIT(&obj_list); 1964 1965 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1966 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1967 1968#ifndef RTLD_INIT_PAGESIZES_EARLY 1969 /* The page size is required by the dynamic memory allocator. */ 1970 init_pagesizes(aux_info); 1971#endif 1972 1973 if (aux_info[AT_OSRELDATE] != NULL) 1974 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1975 1976 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1977 1978 /* Replace the path with a dynamically allocated copy. */ 1979 obj_rtld.path = xstrdup(ld_path_rtld); 1980 1981 r_debug.r_brk = r_debug_state; 1982 r_debug.r_state = RT_CONSISTENT; 1983} 1984 1985/* 1986 * Retrieve the array of supported page sizes. The kernel provides the page 1987 * sizes in increasing order. 1988 */ 1989static void 1990init_pagesizes(Elf_Auxinfo **aux_info) 1991{ 1992 static size_t psa[MAXPAGESIZES]; 1993 int mib[2]; 1994 size_t len, size; 1995 1996 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1997 NULL) { 1998 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1999 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 2000 } else { 2001 len = 2; 2002 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 2003 size = sizeof(psa); 2004 else { 2005 /* As a fallback, retrieve the base page size. */ 2006 size = sizeof(psa[0]); 2007 if (aux_info[AT_PAGESZ] != NULL) { 2008 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 2009 goto psa_filled; 2010 } else { 2011 mib[0] = CTL_HW; 2012 mib[1] = HW_PAGESIZE; 2013 len = 2; 2014 } 2015 } 2016 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 2017 _rtld_error("sysctl for hw.pagesize(s) failed"); 2018 rtld_die(); 2019 } 2020psa_filled: 2021 pagesizes = psa; 2022 } 2023 npagesizes = size / sizeof(pagesizes[0]); 2024 /* Discard any invalid entries at the end of the array. */ 2025 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 2026 npagesizes--; 2027} 2028 2029/* 2030 * Add the init functions from a needed object list (and its recursive 2031 * needed objects) to "list". This is not used directly; it is a helper 2032 * function for initlist_add_objects(). The write lock must be held 2033 * when this function is called. 2034 */ 2035static void 2036initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2037{ 2038 /* Recursively process the successor needed objects. */ 2039 if (needed->next != NULL) 2040 initlist_add_neededs(needed->next, list); 2041 2042 /* Process the current needed object. */ 2043 if (needed->obj != NULL) 2044 initlist_add_objects(needed->obj, needed->obj, list); 2045} 2046 2047/* 2048 * Scan all of the DAGs rooted in the range of objects from "obj" to 2049 * "tail" and add their init functions to "list". This recurses over 2050 * the DAGs and ensure the proper init ordering such that each object's 2051 * needed libraries are initialized before the object itself. At the 2052 * same time, this function adds the objects to the global finalization 2053 * list "list_fini" in the opposite order. The write lock must be 2054 * held when this function is called. 2055 */ 2056static void 2057initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2058{ 2059 Obj_Entry *nobj; 2060 2061 if (obj->init_scanned || obj->init_done) 2062 return; 2063 obj->init_scanned = true; 2064 2065 /* Recursively process the successor objects. */ 2066 nobj = globallist_next(obj); 2067 if (nobj != NULL && obj != tail) 2068 initlist_add_objects(nobj, tail, list); 2069 2070 /* Recursively process the needed objects. */ 2071 if (obj->needed != NULL) 2072 initlist_add_neededs(obj->needed, list); 2073 if (obj->needed_filtees != NULL) 2074 initlist_add_neededs(obj->needed_filtees, list); 2075 if (obj->needed_aux_filtees != NULL) 2076 initlist_add_neededs(obj->needed_aux_filtees, list); 2077 2078 /* Add the object to the init list. */ 2079 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2080 obj->init_array != (Elf_Addr)NULL) 2081 objlist_push_tail(list, obj); 2082 2083 /* Add the object to the global fini list in the reverse order. */ 2084 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2085 && !obj->on_fini_list) { 2086 objlist_push_head(&list_fini, obj); 2087 obj->on_fini_list = true; 2088 } 2089} 2090 2091#ifndef FPTR_TARGET 2092#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2093#endif 2094 2095static void 2096free_needed_filtees(Needed_Entry *n) 2097{ 2098 Needed_Entry *needed, *needed1; 2099 2100 for (needed = n; needed != NULL; needed = needed->next) { 2101 if (needed->obj != NULL) { 2102 dlclose(needed->obj); 2103 needed->obj = NULL; 2104 } 2105 } 2106 for (needed = n; needed != NULL; needed = needed1) { 2107 needed1 = needed->next; 2108 free(needed); 2109 } 2110} 2111 2112static void 2113unload_filtees(Obj_Entry *obj) 2114{ 2115 2116 free_needed_filtees(obj->needed_filtees); 2117 obj->needed_filtees = NULL; 2118 free_needed_filtees(obj->needed_aux_filtees); 2119 obj->needed_aux_filtees = NULL; 2120 obj->filtees_loaded = false; 2121} 2122 2123static void 2124load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2125 RtldLockState *lockstate) 2126{ 2127 2128 for (; needed != NULL; needed = needed->next) { 2129 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2130 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2131 RTLD_LOCAL, lockstate); 2132 } 2133} 2134 2135static void 2136load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2137{ 2138 2139 lock_restart_for_upgrade(lockstate); 2140 if (!obj->filtees_loaded) { 2141 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2142 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2143 obj->filtees_loaded = true; 2144 } 2145} 2146 2147static int 2148process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2149{ 2150 Obj_Entry *obj1; 2151 2152 for (; needed != NULL; needed = needed->next) { 2153 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2154 flags & ~RTLD_LO_NOLOAD); 2155 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2156 return (-1); 2157 } 2158 return (0); 2159} 2160 2161/* 2162 * Given a shared object, traverse its list of needed objects, and load 2163 * each of them. Returns 0 on success. Generates an error message and 2164 * returns -1 on failure. 2165 */ 2166static int 2167load_needed_objects(Obj_Entry *first, int flags) 2168{ 2169 Obj_Entry *obj; 2170 2171 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2172 if (obj->marker) 2173 continue; 2174 if (process_needed(obj, obj->needed, flags) == -1) 2175 return (-1); 2176 } 2177 return (0); 2178} 2179 2180static int 2181load_preload_objects(void) 2182{ 2183 char *p = ld_preload; 2184 Obj_Entry *obj; 2185 static const char delim[] = " \t:;"; 2186 2187 if (p == NULL) 2188 return 0; 2189 2190 p += strspn(p, delim); 2191 while (*p != '\0') { 2192 size_t len = strcspn(p, delim); 2193 char savech; 2194 2195 savech = p[len]; 2196 p[len] = '\0'; 2197 obj = load_object(p, -1, NULL, 0); 2198 if (obj == NULL) 2199 return -1; /* XXX - cleanup */ 2200 obj->z_interpose = true; 2201 p[len] = savech; 2202 p += len; 2203 p += strspn(p, delim); 2204 } 2205 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2206 return 0; 2207} 2208 2209static const char * 2210printable_path(const char *path) 2211{ 2212 2213 return (path == NULL ? "<unknown>" : path); 2214} 2215 2216/* 2217 * Load a shared object into memory, if it is not already loaded. The 2218 * object may be specified by name or by user-supplied file descriptor 2219 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2220 * duplicate is. 2221 * 2222 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2223 * on failure. 2224 */ 2225static Obj_Entry * 2226load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2227{ 2228 Obj_Entry *obj; 2229 int fd; 2230 struct stat sb; 2231 char *path; 2232 2233 fd = -1; 2234 if (name != NULL) { 2235 TAILQ_FOREACH(obj, &obj_list, next) { 2236 if (obj->marker) 2237 continue; 2238 if (object_match_name(obj, name)) 2239 return (obj); 2240 } 2241 2242 path = find_library(name, refobj, &fd); 2243 if (path == NULL) 2244 return (NULL); 2245 } else 2246 path = NULL; 2247 2248 if (fd >= 0) { 2249 /* 2250 * search_library_pathfds() opens a fresh file descriptor for the 2251 * library, so there is no need to dup(). 2252 */ 2253 } else if (fd_u == -1) { 2254 /* 2255 * If we didn't find a match by pathname, or the name is not 2256 * supplied, open the file and check again by device and inode. 2257 * This avoids false mismatches caused by multiple links or ".." 2258 * in pathnames. 2259 * 2260 * To avoid a race, we open the file and use fstat() rather than 2261 * using stat(). 2262 */ 2263 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2264 _rtld_error("Cannot open \"%s\"", path); 2265 free(path); 2266 return (NULL); 2267 } 2268 } else { 2269 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2270 if (fd == -1) { 2271 _rtld_error("Cannot dup fd"); 2272 free(path); 2273 return (NULL); 2274 } 2275 } 2276 if (fstat(fd, &sb) == -1) { 2277 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2278 close(fd); 2279 free(path); 2280 return NULL; 2281 } 2282 TAILQ_FOREACH(obj, &obj_list, next) { 2283 if (obj->marker) 2284 continue; 2285 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2286 break; 2287 } 2288 if (obj != NULL && name != NULL) { 2289 object_add_name(obj, name); 2290 free(path); 2291 close(fd); 2292 return obj; 2293 } 2294 if (flags & RTLD_LO_NOLOAD) { 2295 free(path); 2296 close(fd); 2297 return (NULL); 2298 } 2299 2300 /* First use of this object, so we must map it in */ 2301 obj = do_load_object(fd, name, path, &sb, flags); 2302 if (obj == NULL) 2303 free(path); 2304 close(fd); 2305 2306 return obj; 2307} 2308 2309static Obj_Entry * 2310do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2311 int flags) 2312{ 2313 Obj_Entry *obj; 2314 struct statfs fs; 2315 2316 /* 2317 * but first, make sure that environment variables haven't been 2318 * used to circumvent the noexec flag on a filesystem. 2319 */ 2320 if (dangerous_ld_env) { 2321 if (fstatfs(fd, &fs) != 0) { 2322 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2323 return NULL; 2324 } 2325 if (fs.f_flags & MNT_NOEXEC) { 2326 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2327 return NULL; 2328 } 2329 } 2330 dbg("loading \"%s\"", printable_path(path)); 2331 obj = map_object(fd, printable_path(path), sbp); 2332 if (obj == NULL) 2333 return NULL; 2334 2335 /* 2336 * If DT_SONAME is present in the object, digest_dynamic2 already 2337 * added it to the object names. 2338 */ 2339 if (name != NULL) 2340 object_add_name(obj, name); 2341 obj->path = path; 2342 digest_dynamic(obj, 0); 2343 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2344 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2345 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2346 RTLD_LO_DLOPEN) { 2347 dbg("refusing to load non-loadable \"%s\"", obj->path); 2348 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2349 munmap(obj->mapbase, obj->mapsize); 2350 obj_free(obj); 2351 return (NULL); 2352 } 2353 2354 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2355 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2356 obj_count++; 2357 obj_loads++; 2358 linkmap_add(obj); /* for GDB & dlinfo() */ 2359 max_stack_flags |= obj->stack_flags; 2360 2361 dbg(" %p .. %p: %s", obj->mapbase, 2362 obj->mapbase + obj->mapsize - 1, obj->path); 2363 if (obj->textrel) 2364 dbg(" WARNING: %s has impure text", obj->path); 2365 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2366 obj->path); 2367 2368 return obj; 2369} 2370 2371static Obj_Entry * 2372obj_from_addr(const void *addr) 2373{ 2374 Obj_Entry *obj; 2375 2376 TAILQ_FOREACH(obj, &obj_list, next) { 2377 if (obj->marker) 2378 continue; 2379 if (addr < (void *) obj->mapbase) 2380 continue; 2381 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2382 return obj; 2383 } 2384 return NULL; 2385} 2386 2387static void 2388preinit_main(void) 2389{ 2390 Elf_Addr *preinit_addr; 2391 int index; 2392 2393 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2394 if (preinit_addr == NULL) 2395 return; 2396 2397 for (index = 0; index < obj_main->preinit_array_num; index++) { 2398 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2399 dbg("calling preinit function for %s at %p", obj_main->path, 2400 (void *)preinit_addr[index]); 2401 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2402 0, 0, obj_main->path); 2403 call_init_pointer(obj_main, preinit_addr[index]); 2404 } 2405 } 2406} 2407 2408/* 2409 * Call the finalization functions for each of the objects in "list" 2410 * belonging to the DAG of "root" and referenced once. If NULL "root" 2411 * is specified, every finalization function will be called regardless 2412 * of the reference count and the list elements won't be freed. All of 2413 * the objects are expected to have non-NULL fini functions. 2414 */ 2415static void 2416objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2417{ 2418 Objlist_Entry *elm; 2419 char *saved_msg; 2420 Elf_Addr *fini_addr; 2421 int index; 2422 2423 assert(root == NULL || root->refcount == 1); 2424 2425 /* 2426 * Preserve the current error message since a fini function might 2427 * call into the dynamic linker and overwrite it. 2428 */ 2429 saved_msg = errmsg_save(); 2430 do { 2431 STAILQ_FOREACH(elm, list, link) { 2432 if (root != NULL && (elm->obj->refcount != 1 || 2433 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2434 continue; 2435 /* Remove object from fini list to prevent recursive invocation. */ 2436 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2437 /* 2438 * XXX: If a dlopen() call references an object while the 2439 * fini function is in progress, we might end up trying to 2440 * unload the referenced object in dlclose() or the object 2441 * won't be unloaded although its fini function has been 2442 * called. 2443 */ 2444 lock_release(rtld_bind_lock, lockstate); 2445 2446 /* 2447 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2448 * When this happens, DT_FINI_ARRAY is processed first. 2449 */ 2450 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2451 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2452 for (index = elm->obj->fini_array_num - 1; index >= 0; 2453 index--) { 2454 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2455 dbg("calling fini function for %s at %p", 2456 elm->obj->path, (void *)fini_addr[index]); 2457 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2458 (void *)fini_addr[index], 0, 0, elm->obj->path); 2459 call_initfini_pointer(elm->obj, fini_addr[index]); 2460 } 2461 } 2462 } 2463 if (elm->obj->fini != (Elf_Addr)NULL) { 2464 dbg("calling fini function for %s at %p", elm->obj->path, 2465 (void *)elm->obj->fini); 2466 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2467 0, 0, elm->obj->path); 2468 call_initfini_pointer(elm->obj, elm->obj->fini); 2469 } 2470 wlock_acquire(rtld_bind_lock, lockstate); 2471 /* No need to free anything if process is going down. */ 2472 if (root != NULL) 2473 free(elm); 2474 /* 2475 * We must restart the list traversal after every fini call 2476 * because a dlclose() call from the fini function or from 2477 * another thread might have modified the reference counts. 2478 */ 2479 break; 2480 } 2481 } while (elm != NULL); 2482 errmsg_restore(saved_msg); 2483} 2484 2485/* 2486 * Call the initialization functions for each of the objects in 2487 * "list". All of the objects are expected to have non-NULL init 2488 * functions. 2489 */ 2490static void 2491objlist_call_init(Objlist *list, RtldLockState *lockstate) 2492{ 2493 Objlist_Entry *elm; 2494 Obj_Entry *obj; 2495 char *saved_msg; 2496 Elf_Addr *init_addr; 2497 int index; 2498 2499 /* 2500 * Clean init_scanned flag so that objects can be rechecked and 2501 * possibly initialized earlier if any of vectors called below 2502 * cause the change by using dlopen. 2503 */ 2504 TAILQ_FOREACH(obj, &obj_list, next) { 2505 if (obj->marker) 2506 continue; 2507 obj->init_scanned = false; 2508 } 2509 2510 /* 2511 * Preserve the current error message since an init function might 2512 * call into the dynamic linker and overwrite it. 2513 */ 2514 saved_msg = errmsg_save(); 2515 STAILQ_FOREACH(elm, list, link) { 2516 if (elm->obj->init_done) /* Initialized early. */ 2517 continue; 2518 /* 2519 * Race: other thread might try to use this object before current 2520 * one completes the initilization. Not much can be done here 2521 * without better locking. 2522 */ 2523 elm->obj->init_done = true; 2524 lock_release(rtld_bind_lock, lockstate); 2525 2526 /* 2527 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2528 * When this happens, DT_INIT is processed first. 2529 */ 2530 if (elm->obj->init != (Elf_Addr)NULL) { 2531 dbg("calling init function for %s at %p", elm->obj->path, 2532 (void *)elm->obj->init); 2533 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2534 0, 0, elm->obj->path); 2535 call_initfini_pointer(elm->obj, elm->obj->init); 2536 } 2537 init_addr = (Elf_Addr *)elm->obj->init_array; 2538 if (init_addr != NULL) { 2539 for (index = 0; index < elm->obj->init_array_num; index++) { 2540 if (init_addr[index] != 0 && init_addr[index] != 1) { 2541 dbg("calling init function for %s at %p", elm->obj->path, 2542 (void *)init_addr[index]); 2543 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2544 (void *)init_addr[index], 0, 0, elm->obj->path); 2545 call_init_pointer(elm->obj, init_addr[index]); 2546 } 2547 } 2548 } 2549 wlock_acquire(rtld_bind_lock, lockstate); 2550 } 2551 errmsg_restore(saved_msg); 2552} 2553 2554static void 2555objlist_clear(Objlist *list) 2556{ 2557 Objlist_Entry *elm; 2558 2559 while (!STAILQ_EMPTY(list)) { 2560 elm = STAILQ_FIRST(list); 2561 STAILQ_REMOVE_HEAD(list, link); 2562 free(elm); 2563 } 2564} 2565 2566static Objlist_Entry * 2567objlist_find(Objlist *list, const Obj_Entry *obj) 2568{ 2569 Objlist_Entry *elm; 2570 2571 STAILQ_FOREACH(elm, list, link) 2572 if (elm->obj == obj) 2573 return elm; 2574 return NULL; 2575} 2576 2577static void 2578objlist_init(Objlist *list) 2579{ 2580 STAILQ_INIT(list); 2581} 2582 2583static void 2584objlist_push_head(Objlist *list, Obj_Entry *obj) 2585{ 2586 Objlist_Entry *elm; 2587 2588 elm = NEW(Objlist_Entry); 2589 elm->obj = obj; 2590 STAILQ_INSERT_HEAD(list, elm, link); 2591} 2592 2593static void 2594objlist_push_tail(Objlist *list, Obj_Entry *obj) 2595{ 2596 Objlist_Entry *elm; 2597 2598 elm = NEW(Objlist_Entry); 2599 elm->obj = obj; 2600 STAILQ_INSERT_TAIL(list, elm, link); 2601} 2602 2603static void 2604objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2605{ 2606 Objlist_Entry *elm, *listelm; 2607 2608 STAILQ_FOREACH(listelm, list, link) { 2609 if (listelm->obj == listobj) 2610 break; 2611 } 2612 elm = NEW(Objlist_Entry); 2613 elm->obj = obj; 2614 if (listelm != NULL) 2615 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2616 else 2617 STAILQ_INSERT_TAIL(list, elm, link); 2618} 2619 2620static void 2621objlist_remove(Objlist *list, Obj_Entry *obj) 2622{ 2623 Objlist_Entry *elm; 2624 2625 if ((elm = objlist_find(list, obj)) != NULL) { 2626 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2627 free(elm); 2628 } 2629} 2630 2631/* 2632 * Relocate dag rooted in the specified object. 2633 * Returns 0 on success, or -1 on failure. 2634 */ 2635 2636static int 2637relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2638 int flags, RtldLockState *lockstate) 2639{ 2640 Objlist_Entry *elm; 2641 int error; 2642 2643 error = 0; 2644 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2645 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2646 lockstate); 2647 if (error == -1) 2648 break; 2649 } 2650 return (error); 2651} 2652 2653/* 2654 * Prepare for, or clean after, relocating an object marked with 2655 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2656 * segments are remapped read-write. After relocations are done, the 2657 * segment's permissions are returned back to the modes specified in 2658 * the phdrs. If any relocation happened, or always for wired 2659 * program, COW is triggered. 2660 */ 2661static int 2662reloc_textrel_prot(Obj_Entry *obj, bool before) 2663{ 2664 const Elf_Phdr *ph; 2665 void *base; 2666 size_t l, sz; 2667 int prot; 2668 2669 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2670 l--, ph++) { 2671 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2672 continue; 2673 base = obj->relocbase + trunc_page(ph->p_vaddr); 2674 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2675 trunc_page(ph->p_vaddr); 2676 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2677 if (mprotect(base, sz, prot) == -1) { 2678 _rtld_error("%s: Cannot write-%sable text segment: %s", 2679 obj->path, before ? "en" : "dis", 2680 rtld_strerror(errno)); 2681 return (-1); 2682 } 2683 } 2684 return (0); 2685} 2686 2687/* 2688 * Relocate single object. 2689 * Returns 0 on success, or -1 on failure. 2690 */ 2691static int 2692relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2693 int flags, RtldLockState *lockstate) 2694{ 2695 2696 if (obj->relocated) 2697 return (0); 2698 obj->relocated = true; 2699 if (obj != rtldobj) 2700 dbg("relocating \"%s\"", obj->path); 2701 2702 if (obj->symtab == NULL || obj->strtab == NULL || 2703 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2704 _rtld_error("%s: Shared object has no run-time symbol table", 2705 obj->path); 2706 return (-1); 2707 } 2708 2709 /* There are relocations to the write-protected text segment. */ 2710 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2711 return (-1); 2712 2713 /* Process the non-PLT non-IFUNC relocations. */ 2714 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2715 return (-1); 2716 2717 /* Re-protected the text segment. */ 2718 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2719 return (-1); 2720 2721 /* Set the special PLT or GOT entries. */ 2722 init_pltgot(obj); 2723 2724 /* Process the PLT relocations. */ 2725 if (reloc_plt(obj) == -1) 2726 return (-1); 2727 /* Relocate the jump slots if we are doing immediate binding. */ 2728 if (obj->bind_now || bind_now) 2729 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2730 return (-1); 2731 2732 /* 2733 * Process the non-PLT IFUNC relocations. The relocations are 2734 * processed in two phases, because IFUNC resolvers may 2735 * reference other symbols, which must be readily processed 2736 * before resolvers are called. 2737 */ 2738 if (obj->non_plt_gnu_ifunc && 2739 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2740 return (-1); 2741 2742 if (obj->relro_size > 0) { 2743 if (mprotect(obj->relro_page, obj->relro_size, 2744 PROT_READ) == -1) { 2745 _rtld_error("%s: Cannot enforce relro protection: %s", 2746 obj->path, rtld_strerror(errno)); 2747 return (-1); 2748 } 2749 } 2750 2751 /* 2752 * Set up the magic number and version in the Obj_Entry. These 2753 * were checked in the crt1.o from the original ElfKit, so we 2754 * set them for backward compatibility. 2755 */ 2756 obj->magic = RTLD_MAGIC; 2757 obj->version = RTLD_VERSION; 2758 2759 return (0); 2760} 2761 2762/* 2763 * Relocate newly-loaded shared objects. The argument is a pointer to 2764 * the Obj_Entry for the first such object. All objects from the first 2765 * to the end of the list of objects are relocated. Returns 0 on success, 2766 * or -1 on failure. 2767 */ 2768static int 2769relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2770 int flags, RtldLockState *lockstate) 2771{ 2772 Obj_Entry *obj; 2773 int error; 2774 2775 for (error = 0, obj = first; obj != NULL; 2776 obj = TAILQ_NEXT(obj, next)) { 2777 if (obj->marker) 2778 continue; 2779 error = relocate_object(obj, bind_now, rtldobj, flags, 2780 lockstate); 2781 if (error == -1) 2782 break; 2783 } 2784 return (error); 2785} 2786 2787/* 2788 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2789 * referencing STT_GNU_IFUNC symbols is postponed till the other 2790 * relocations are done. The indirect functions specified as 2791 * ifunc are allowed to call other symbols, so we need to have 2792 * objects relocated before asking for resolution from indirects. 2793 * 2794 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2795 * instead of the usual lazy handling of PLT slots. It is 2796 * consistent with how GNU does it. 2797 */ 2798static int 2799resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2800 RtldLockState *lockstate) 2801{ 2802 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2803 return (-1); 2804 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2805 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2806 return (-1); 2807 return (0); 2808} 2809 2810static int 2811resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2812 RtldLockState *lockstate) 2813{ 2814 Obj_Entry *obj; 2815 2816 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2817 if (obj->marker) 2818 continue; 2819 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2820 return (-1); 2821 } 2822 return (0); 2823} 2824 2825static int 2826initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2827 RtldLockState *lockstate) 2828{ 2829 Objlist_Entry *elm; 2830 2831 STAILQ_FOREACH(elm, list, link) { 2832 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2833 lockstate) == -1) 2834 return (-1); 2835 } 2836 return (0); 2837} 2838 2839/* 2840 * Cleanup procedure. It will be called (by the atexit mechanism) just 2841 * before the process exits. 2842 */ 2843static void 2844rtld_exit(void) 2845{ 2846 RtldLockState lockstate; 2847 2848 wlock_acquire(rtld_bind_lock, &lockstate); 2849 dbg("rtld_exit()"); 2850 objlist_call_fini(&list_fini, NULL, &lockstate); 2851 /* No need to remove the items from the list, since we are exiting. */ 2852 if (!libmap_disable) 2853 lm_fini(); 2854 lock_release(rtld_bind_lock, &lockstate); 2855} 2856 2857/* 2858 * Iterate over a search path, translate each element, and invoke the 2859 * callback on the result. 2860 */ 2861static void * 2862path_enumerate(const char *path, path_enum_proc callback, void *arg) 2863{ 2864 const char *trans; 2865 if (path == NULL) 2866 return (NULL); 2867 2868 path += strspn(path, ":;"); 2869 while (*path != '\0') { 2870 size_t len; 2871 char *res; 2872 2873 len = strcspn(path, ":;"); 2874 trans = lm_findn(NULL, path, len); 2875 if (trans) 2876 res = callback(trans, strlen(trans), arg); 2877 else 2878 res = callback(path, len, arg); 2879 2880 if (res != NULL) 2881 return (res); 2882 2883 path += len; 2884 path += strspn(path, ":;"); 2885 } 2886 2887 return (NULL); 2888} 2889 2890struct try_library_args { 2891 const char *name; 2892 size_t namelen; 2893 char *buffer; 2894 size_t buflen; 2895}; 2896 2897static void * 2898try_library_path(const char *dir, size_t dirlen, void *param) 2899{ 2900 struct try_library_args *arg; 2901 2902 arg = param; 2903 if (*dir == '/' || trust) { 2904 char *pathname; 2905 2906 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2907 return (NULL); 2908 2909 pathname = arg->buffer; 2910 strncpy(pathname, dir, dirlen); 2911 pathname[dirlen] = '/'; 2912 strcpy(pathname + dirlen + 1, arg->name); 2913 2914 dbg(" Trying \"%s\"", pathname); 2915 if (access(pathname, F_OK) == 0) { /* We found it */ 2916 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2917 strcpy(pathname, arg->buffer); 2918 return (pathname); 2919 } 2920 } 2921 return (NULL); 2922} 2923 2924static char * 2925search_library_path(const char *name, const char *path) 2926{ 2927 char *p; 2928 struct try_library_args arg; 2929 2930 if (path == NULL) 2931 return NULL; 2932 2933 arg.name = name; 2934 arg.namelen = strlen(name); 2935 arg.buffer = xmalloc(PATH_MAX); 2936 arg.buflen = PATH_MAX; 2937 2938 p = path_enumerate(path, try_library_path, &arg); 2939 2940 free(arg.buffer); 2941 2942 return (p); 2943} 2944 2945 2946/* 2947 * Finds the library with the given name using the directory descriptors 2948 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2949 * 2950 * Returns a freshly-opened close-on-exec file descriptor for the library, 2951 * or -1 if the library cannot be found. 2952 */ 2953static char * 2954search_library_pathfds(const char *name, const char *path, int *fdp) 2955{ 2956 char *envcopy, *fdstr, *found, *last_token; 2957 size_t len; 2958 int dirfd, fd; 2959 2960 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2961 2962 /* Don't load from user-specified libdirs into setuid binaries. */ 2963 if (!trust) 2964 return (NULL); 2965 2966 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2967 if (path == NULL) 2968 return (NULL); 2969 2970 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2971 if (name[0] == '/') { 2972 dbg("Absolute path (%s) passed to %s", name, __func__); 2973 return (NULL); 2974 } 2975 2976 /* 2977 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2978 * copy of the path, as strtok_r rewrites separator tokens 2979 * with '\0'. 2980 */ 2981 found = NULL; 2982 envcopy = xstrdup(path); 2983 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2984 fdstr = strtok_r(NULL, ":", &last_token)) { 2985 dirfd = parse_libdir(fdstr); 2986 if (dirfd < 0) 2987 break; 2988 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2989 if (fd >= 0) { 2990 *fdp = fd; 2991 len = strlen(fdstr) + strlen(name) + 3; 2992 found = xmalloc(len); 2993 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2994 _rtld_error("error generating '%d/%s'", 2995 dirfd, name); 2996 rtld_die(); 2997 } 2998 dbg("open('%s') => %d", found, fd); 2999 break; 3000 } 3001 } 3002 free(envcopy); 3003 3004 return (found); 3005} 3006 3007 3008int 3009dlclose(void *handle) 3010{ 3011 Obj_Entry *root; 3012 RtldLockState lockstate; 3013 3014 wlock_acquire(rtld_bind_lock, &lockstate); 3015 root = dlcheck(handle); 3016 if (root == NULL) { 3017 lock_release(rtld_bind_lock, &lockstate); 3018 return -1; 3019 } 3020 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 3021 root->path); 3022 3023 /* Unreference the object and its dependencies. */ 3024 root->dl_refcount--; 3025 3026 if (root->refcount == 1) { 3027 /* 3028 * The object will be no longer referenced, so we must unload it. 3029 * First, call the fini functions. 3030 */ 3031 objlist_call_fini(&list_fini, root, &lockstate); 3032 3033 unref_dag(root); 3034 3035 /* Finish cleaning up the newly-unreferenced objects. */ 3036 GDB_STATE(RT_DELETE,&root->linkmap); 3037 unload_object(root); 3038 GDB_STATE(RT_CONSISTENT,NULL); 3039 } else 3040 unref_dag(root); 3041 3042 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 3043 lock_release(rtld_bind_lock, &lockstate); 3044 return 0; 3045} 3046 3047char * 3048dlerror(void) 3049{ 3050 char *msg = error_message; 3051 error_message = NULL; 3052 return msg; 3053} 3054 3055/* 3056 * This function is deprecated and has no effect. 3057 */ 3058void 3059dllockinit(void *context, 3060 void *(*lock_create)(void *context), 3061 void (*rlock_acquire)(void *lock), 3062 void (*wlock_acquire)(void *lock), 3063 void (*lock_release)(void *lock), 3064 void (*lock_destroy)(void *lock), 3065 void (*context_destroy)(void *context)) 3066{ 3067 static void *cur_context; 3068 static void (*cur_context_destroy)(void *); 3069 3070 /* Just destroy the context from the previous call, if necessary. */ 3071 if (cur_context_destroy != NULL) 3072 cur_context_destroy(cur_context); 3073 cur_context = context; 3074 cur_context_destroy = context_destroy; 3075} 3076 3077void * 3078dlopen(const char *name, int mode) 3079{ 3080 3081 return (rtld_dlopen(name, -1, mode)); 3082} 3083 3084void * 3085fdlopen(int fd, int mode) 3086{ 3087 3088 return (rtld_dlopen(NULL, fd, mode)); 3089} 3090 3091static void * 3092rtld_dlopen(const char *name, int fd, int mode) 3093{ 3094 RtldLockState lockstate; 3095 int lo_flags; 3096 3097 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 3098 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 3099 if (ld_tracing != NULL) { 3100 rlock_acquire(rtld_bind_lock, &lockstate); 3101 if (sigsetjmp(lockstate.env, 0) != 0) 3102 lock_upgrade(rtld_bind_lock, &lockstate); 3103 environ = (char **)*get_program_var_addr("environ", &lockstate); 3104 lock_release(rtld_bind_lock, &lockstate); 3105 } 3106 lo_flags = RTLD_LO_DLOPEN; 3107 if (mode & RTLD_NODELETE) 3108 lo_flags |= RTLD_LO_NODELETE; 3109 if (mode & RTLD_NOLOAD) 3110 lo_flags |= RTLD_LO_NOLOAD; 3111 if (ld_tracing != NULL) 3112 lo_flags |= RTLD_LO_TRACE; 3113 3114 return (dlopen_object(name, fd, obj_main, lo_flags, 3115 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3116} 3117 3118static void 3119dlopen_cleanup(Obj_Entry *obj) 3120{ 3121 3122 obj->dl_refcount--; 3123 unref_dag(obj); 3124 if (obj->refcount == 0) 3125 unload_object(obj); 3126} 3127 3128static Obj_Entry * 3129dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3130 int mode, RtldLockState *lockstate) 3131{ 3132 Obj_Entry *old_obj_tail; 3133 Obj_Entry *obj; 3134 Objlist initlist; 3135 RtldLockState mlockstate; 3136 int result; 3137 3138 objlist_init(&initlist); 3139 3140 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3141 wlock_acquire(rtld_bind_lock, &mlockstate); 3142 lockstate = &mlockstate; 3143 } 3144 GDB_STATE(RT_ADD,NULL); 3145 3146 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3147 obj = NULL; 3148 if (name == NULL && fd == -1) { 3149 obj = obj_main; 3150 obj->refcount++; 3151 } else { 3152 obj = load_object(name, fd, refobj, lo_flags); 3153 } 3154 3155 if (obj) { 3156 obj->dl_refcount++; 3157 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3158 objlist_push_tail(&list_global, obj); 3159 if (globallist_next(old_obj_tail) != NULL) { 3160 /* We loaded something new. */ 3161 assert(globallist_next(old_obj_tail) == obj); 3162 result = load_needed_objects(obj, 3163 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3164 init_dag(obj); 3165 ref_dag(obj); 3166 if (result != -1) 3167 result = rtld_verify_versions(&obj->dagmembers); 3168 if (result != -1 && ld_tracing) 3169 goto trace; 3170 if (result == -1 || relocate_object_dag(obj, 3171 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3172 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3173 lockstate) == -1) { 3174 dlopen_cleanup(obj); 3175 obj = NULL; 3176 } else if (lo_flags & RTLD_LO_EARLY) { 3177 /* 3178 * Do not call the init functions for early loaded 3179 * filtees. The image is still not initialized enough 3180 * for them to work. 3181 * 3182 * Our object is found by the global object list and 3183 * will be ordered among all init calls done right 3184 * before transferring control to main. 3185 */ 3186 } else { 3187 /* Make list of init functions to call. */ 3188 initlist_add_objects(obj, obj, &initlist); 3189 } 3190 /* 3191 * Process all no_delete or global objects here, given 3192 * them own DAGs to prevent their dependencies from being 3193 * unloaded. This has to be done after we have loaded all 3194 * of the dependencies, so that we do not miss any. 3195 */ 3196 if (obj != NULL) 3197 process_z(obj); 3198 } else { 3199 /* 3200 * Bump the reference counts for objects on this DAG. If 3201 * this is the first dlopen() call for the object that was 3202 * already loaded as a dependency, initialize the dag 3203 * starting at it. 3204 */ 3205 init_dag(obj); 3206 ref_dag(obj); 3207 3208 if ((lo_flags & RTLD_LO_TRACE) != 0) 3209 goto trace; 3210 } 3211 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3212 obj->z_nodelete) && !obj->ref_nodel) { 3213 dbg("obj %s nodelete", obj->path); 3214 ref_dag(obj); 3215 obj->z_nodelete = obj->ref_nodel = true; 3216 } 3217 } 3218 3219 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3220 name); 3221 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3222 3223 if (!(lo_flags & RTLD_LO_EARLY)) { 3224 map_stacks_exec(lockstate); 3225 } 3226 3227 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3228 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3229 lockstate) == -1) { 3230 objlist_clear(&initlist); 3231 dlopen_cleanup(obj); 3232 if (lockstate == &mlockstate) 3233 lock_release(rtld_bind_lock, lockstate); 3234 return (NULL); 3235 } 3236 3237 if (!(lo_flags & RTLD_LO_EARLY)) { 3238 /* Call the init functions. */ 3239 objlist_call_init(&initlist, lockstate); 3240 } 3241 objlist_clear(&initlist); 3242 if (lockstate == &mlockstate) 3243 lock_release(rtld_bind_lock, lockstate); 3244 return obj; 3245trace: 3246 trace_loaded_objects(obj); 3247 if (lockstate == &mlockstate) 3248 lock_release(rtld_bind_lock, lockstate); 3249 exit(0); 3250} 3251 3252static void * 3253do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3254 int flags) 3255{ 3256 DoneList donelist; 3257 const Obj_Entry *obj, *defobj; 3258 const Elf_Sym *def; 3259 SymLook req; 3260 RtldLockState lockstate; 3261 tls_index ti; 3262 void *sym; 3263 int res; 3264 3265 def = NULL; 3266 defobj = NULL; 3267 symlook_init(&req, name); 3268 req.ventry = ve; 3269 req.flags = flags | SYMLOOK_IN_PLT; 3270 req.lockstate = &lockstate; 3271 3272 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3273 rlock_acquire(rtld_bind_lock, &lockstate); 3274 if (sigsetjmp(lockstate.env, 0) != 0) 3275 lock_upgrade(rtld_bind_lock, &lockstate); 3276 if (handle == NULL || handle == RTLD_NEXT || 3277 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3278 3279 if ((obj = obj_from_addr(retaddr)) == NULL) { 3280 _rtld_error("Cannot determine caller's shared object"); 3281 lock_release(rtld_bind_lock, &lockstate); 3282 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3283 return NULL; 3284 } 3285 if (handle == NULL) { /* Just the caller's shared object. */ 3286 res = symlook_obj(&req, obj); 3287 if (res == 0) { 3288 def = req.sym_out; 3289 defobj = req.defobj_out; 3290 } 3291 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3292 handle == RTLD_SELF) { /* ... caller included */ 3293 if (handle == RTLD_NEXT) 3294 obj = globallist_next(obj); 3295 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3296 if (obj->marker) 3297 continue; 3298 res = symlook_obj(&req, obj); 3299 if (res == 0) { 3300 if (def == NULL || 3301 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3302 def = req.sym_out; 3303 defobj = req.defobj_out; 3304 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3305 break; 3306 } 3307 } 3308 } 3309 /* 3310 * Search the dynamic linker itself, and possibly resolve the 3311 * symbol from there. This is how the application links to 3312 * dynamic linker services such as dlopen. 3313 */ 3314 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3315 res = symlook_obj(&req, &obj_rtld); 3316 if (res == 0) { 3317 def = req.sym_out; 3318 defobj = req.defobj_out; 3319 } 3320 } 3321 } else { 3322 assert(handle == RTLD_DEFAULT); 3323 res = symlook_default(&req, obj); 3324 if (res == 0) { 3325 defobj = req.defobj_out; 3326 def = req.sym_out; 3327 } 3328 } 3329 } else { 3330 if ((obj = dlcheck(handle)) == NULL) { 3331 lock_release(rtld_bind_lock, &lockstate); 3332 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3333 return NULL; 3334 } 3335 3336 donelist_init(&donelist); 3337 if (obj->mainprog) { 3338 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3339 res = symlook_global(&req, &donelist); 3340 if (res == 0) { 3341 def = req.sym_out; 3342 defobj = req.defobj_out; 3343 } 3344 /* 3345 * Search the dynamic linker itself, and possibly resolve the 3346 * symbol from there. This is how the application links to 3347 * dynamic linker services such as dlopen. 3348 */ 3349 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3350 res = symlook_obj(&req, &obj_rtld); 3351 if (res == 0) { 3352 def = req.sym_out; 3353 defobj = req.defobj_out; 3354 } 3355 } 3356 } 3357 else { 3358 /* Search the whole DAG rooted at the given object. */ 3359 res = symlook_list(&req, &obj->dagmembers, &donelist); 3360 if (res == 0) { 3361 def = req.sym_out; 3362 defobj = req.defobj_out; 3363 } 3364 } 3365 } 3366 3367 if (def != NULL) { 3368 lock_release(rtld_bind_lock, &lockstate); 3369 3370 /* 3371 * The value required by the caller is derived from the value 3372 * of the symbol. this is simply the relocated value of the 3373 * symbol. 3374 */ 3375 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3376 sym = make_function_pointer(def, defobj); 3377 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3378 sym = rtld_resolve_ifunc(defobj, def); 3379 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3380 ti.ti_module = defobj->tlsindex; 3381 ti.ti_offset = def->st_value; 3382 sym = __tls_get_addr(&ti); 3383 } else 3384 sym = defobj->relocbase + def->st_value; 3385 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3386 return (sym); 3387 } 3388 3389 _rtld_error("Undefined symbol \"%s\"", name); 3390 lock_release(rtld_bind_lock, &lockstate); 3391 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3392 return NULL; 3393} 3394 3395void * 3396dlsym(void *handle, const char *name) 3397{ 3398 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3399 SYMLOOK_DLSYM); 3400} 3401 3402dlfunc_t 3403dlfunc(void *handle, const char *name) 3404{ 3405 union { 3406 void *d; 3407 dlfunc_t f; 3408 } rv; 3409 3410 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3411 SYMLOOK_DLSYM); 3412 return (rv.f); 3413} 3414 3415void * 3416dlvsym(void *handle, const char *name, const char *version) 3417{ 3418 Ver_Entry ventry; 3419 3420 ventry.name = version; 3421 ventry.file = NULL; 3422 ventry.hash = elf_hash(version); 3423 ventry.flags= 0; 3424 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3425 SYMLOOK_DLSYM); 3426} 3427 3428int 3429_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3430{ 3431 const Obj_Entry *obj; 3432 RtldLockState lockstate; 3433 3434 rlock_acquire(rtld_bind_lock, &lockstate); 3435 obj = obj_from_addr(addr); 3436 if (obj == NULL) { 3437 _rtld_error("No shared object contains address"); 3438 lock_release(rtld_bind_lock, &lockstate); 3439 return (0); 3440 } 3441 rtld_fill_dl_phdr_info(obj, phdr_info); 3442 lock_release(rtld_bind_lock, &lockstate); 3443 return (1); 3444} 3445 3446int 3447dladdr(const void *addr, Dl_info *info) 3448{ 3449 const Obj_Entry *obj; 3450 const Elf_Sym *def; 3451 void *symbol_addr; 3452 unsigned long symoffset; 3453 RtldLockState lockstate; 3454 3455 rlock_acquire(rtld_bind_lock, &lockstate); 3456 obj = obj_from_addr(addr); 3457 if (obj == NULL) { 3458 _rtld_error("No shared object contains address"); 3459 lock_release(rtld_bind_lock, &lockstate); 3460 return 0; 3461 } 3462 info->dli_fname = obj->path; 3463 info->dli_fbase = obj->mapbase; 3464 info->dli_saddr = (void *)0; 3465 info->dli_sname = NULL; 3466 3467 /* 3468 * Walk the symbol list looking for the symbol whose address is 3469 * closest to the address sent in. 3470 */ 3471 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3472 def = obj->symtab + symoffset; 3473 3474 /* 3475 * For skip the symbol if st_shndx is either SHN_UNDEF or 3476 * SHN_COMMON. 3477 */ 3478 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3479 continue; 3480 3481 /* 3482 * If the symbol is greater than the specified address, or if it 3483 * is further away from addr than the current nearest symbol, 3484 * then reject it. 3485 */ 3486 symbol_addr = obj->relocbase + def->st_value; 3487 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3488 continue; 3489 3490 /* Update our idea of the nearest symbol. */ 3491 info->dli_sname = obj->strtab + def->st_name; 3492 info->dli_saddr = symbol_addr; 3493 3494 /* Exact match? */ 3495 if (info->dli_saddr == addr) 3496 break; 3497 } 3498 lock_release(rtld_bind_lock, &lockstate); 3499 return 1; 3500} 3501 3502int 3503dlinfo(void *handle, int request, void *p) 3504{ 3505 const Obj_Entry *obj; 3506 RtldLockState lockstate; 3507 int error; 3508 3509 rlock_acquire(rtld_bind_lock, &lockstate); 3510 3511 if (handle == NULL || handle == RTLD_SELF) { 3512 void *retaddr; 3513 3514 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3515 if ((obj = obj_from_addr(retaddr)) == NULL) 3516 _rtld_error("Cannot determine caller's shared object"); 3517 } else 3518 obj = dlcheck(handle); 3519 3520 if (obj == NULL) { 3521 lock_release(rtld_bind_lock, &lockstate); 3522 return (-1); 3523 } 3524 3525 error = 0; 3526 switch (request) { 3527 case RTLD_DI_LINKMAP: 3528 *((struct link_map const **)p) = &obj->linkmap; 3529 break; 3530 case RTLD_DI_ORIGIN: 3531 error = rtld_dirname(obj->path, p); 3532 break; 3533 3534 case RTLD_DI_SERINFOSIZE: 3535 case RTLD_DI_SERINFO: 3536 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3537 break; 3538 3539 default: 3540 _rtld_error("Invalid request %d passed to dlinfo()", request); 3541 error = -1; 3542 } 3543 3544 lock_release(rtld_bind_lock, &lockstate); 3545 3546 return (error); 3547} 3548 3549static void 3550rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3551{ 3552 3553 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3554 phdr_info->dlpi_name = obj->path; 3555 phdr_info->dlpi_phdr = obj->phdr; 3556 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3557 phdr_info->dlpi_tls_modid = obj->tlsindex; 3558 phdr_info->dlpi_tls_data = obj->tlsinit; 3559 phdr_info->dlpi_adds = obj_loads; 3560 phdr_info->dlpi_subs = obj_loads - obj_count; 3561} 3562 3563int 3564dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3565{ 3566 struct dl_phdr_info phdr_info; 3567 Obj_Entry *obj, marker; 3568 RtldLockState bind_lockstate, phdr_lockstate; 3569 int error; 3570 3571 bzero(&marker, sizeof(marker)); 3572 marker.marker = true; 3573 error = 0; 3574 3575 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3576 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3577 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3578 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3579 rtld_fill_dl_phdr_info(obj, &phdr_info); 3580 lock_release(rtld_bind_lock, &bind_lockstate); 3581 3582 error = callback(&phdr_info, sizeof phdr_info, param); 3583 3584 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3585 obj = globallist_next(&marker); 3586 TAILQ_REMOVE(&obj_list, &marker, next); 3587 if (error != 0) { 3588 lock_release(rtld_bind_lock, &bind_lockstate); 3589 lock_release(rtld_phdr_lock, &phdr_lockstate); 3590 return (error); 3591 } 3592 } 3593 3594 if (error == 0) { 3595 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3596 lock_release(rtld_bind_lock, &bind_lockstate); 3597 error = callback(&phdr_info, sizeof(phdr_info), param); 3598 } 3599 lock_release(rtld_phdr_lock, &phdr_lockstate); 3600 return (error); 3601} 3602 3603static void * 3604fill_search_info(const char *dir, size_t dirlen, void *param) 3605{ 3606 struct fill_search_info_args *arg; 3607 3608 arg = param; 3609 3610 if (arg->request == RTLD_DI_SERINFOSIZE) { 3611 arg->serinfo->dls_cnt ++; 3612 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3613 } else { 3614 struct dl_serpath *s_entry; 3615 3616 s_entry = arg->serpath; 3617 s_entry->dls_name = arg->strspace; 3618 s_entry->dls_flags = arg->flags; 3619 3620 strncpy(arg->strspace, dir, dirlen); 3621 arg->strspace[dirlen] = '\0'; 3622 3623 arg->strspace += dirlen + 1; 3624 arg->serpath++; 3625 } 3626 3627 return (NULL); 3628} 3629 3630static int 3631do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3632{ 3633 struct dl_serinfo _info; 3634 struct fill_search_info_args args; 3635 3636 args.request = RTLD_DI_SERINFOSIZE; 3637 args.serinfo = &_info; 3638 3639 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3640 _info.dls_cnt = 0; 3641 3642 path_enumerate(obj->rpath, fill_search_info, &args); 3643 path_enumerate(ld_library_path, fill_search_info, &args); 3644 path_enumerate(obj->runpath, fill_search_info, &args); 3645 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3646 if (!obj->z_nodeflib) 3647 path_enumerate(ld_standard_library_path, fill_search_info, &args); 3648 3649 3650 if (request == RTLD_DI_SERINFOSIZE) { 3651 info->dls_size = _info.dls_size; 3652 info->dls_cnt = _info.dls_cnt; 3653 return (0); 3654 } 3655 3656 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3657 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3658 return (-1); 3659 } 3660 3661 args.request = RTLD_DI_SERINFO; 3662 args.serinfo = info; 3663 args.serpath = &info->dls_serpath[0]; 3664 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3665 3666 args.flags = LA_SER_RUNPATH; 3667 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3668 return (-1); 3669 3670 args.flags = LA_SER_LIBPATH; 3671 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3672 return (-1); 3673 3674 args.flags = LA_SER_RUNPATH; 3675 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3676 return (-1); 3677 3678 args.flags = LA_SER_CONFIG; 3679 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3680 != NULL) 3681 return (-1); 3682 3683 args.flags = LA_SER_DEFAULT; 3684 if (!obj->z_nodeflib && 3685 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL) 3686 return (-1); 3687 return (0); 3688} 3689 3690static int 3691rtld_dirname(const char *path, char *bname) 3692{ 3693 const char *endp; 3694 3695 /* Empty or NULL string gets treated as "." */ 3696 if (path == NULL || *path == '\0') { 3697 bname[0] = '.'; 3698 bname[1] = '\0'; 3699 return (0); 3700 } 3701 3702 /* Strip trailing slashes */ 3703 endp = path + strlen(path) - 1; 3704 while (endp > path && *endp == '/') 3705 endp--; 3706 3707 /* Find the start of the dir */ 3708 while (endp > path && *endp != '/') 3709 endp--; 3710 3711 /* Either the dir is "/" or there are no slashes */ 3712 if (endp == path) { 3713 bname[0] = *endp == '/' ? '/' : '.'; 3714 bname[1] = '\0'; 3715 return (0); 3716 } else { 3717 do { 3718 endp--; 3719 } while (endp > path && *endp == '/'); 3720 } 3721 3722 if (endp - path + 2 > PATH_MAX) 3723 { 3724 _rtld_error("Filename is too long: %s", path); 3725 return(-1); 3726 } 3727 3728 strncpy(bname, path, endp - path + 1); 3729 bname[endp - path + 1] = '\0'; 3730 return (0); 3731} 3732 3733static int 3734rtld_dirname_abs(const char *path, char *base) 3735{ 3736 char *last; 3737 3738 if (realpath(path, base) == NULL) 3739 return (-1); 3740 dbg("%s -> %s", path, base); 3741 last = strrchr(base, '/'); 3742 if (last == NULL) 3743 return (-1); 3744 if (last != base) 3745 *last = '\0'; 3746 return (0); 3747} 3748 3749static void 3750linkmap_add(Obj_Entry *obj) 3751{ 3752 struct link_map *l = &obj->linkmap; 3753 struct link_map *prev; 3754 3755 obj->linkmap.l_name = obj->path; 3756 obj->linkmap.l_addr = obj->mapbase; 3757 obj->linkmap.l_ld = obj->dynamic; 3758#ifdef __mips__ 3759 /* GDB needs load offset on MIPS to use the symbols */ 3760 obj->linkmap.l_offs = obj->relocbase; 3761#endif 3762 3763 if (r_debug.r_map == NULL) { 3764 r_debug.r_map = l; 3765 return; 3766 } 3767 3768 /* 3769 * Scan to the end of the list, but not past the entry for the 3770 * dynamic linker, which we want to keep at the very end. 3771 */ 3772 for (prev = r_debug.r_map; 3773 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3774 prev = prev->l_next) 3775 ; 3776 3777 /* Link in the new entry. */ 3778 l->l_prev = prev; 3779 l->l_next = prev->l_next; 3780 if (l->l_next != NULL) 3781 l->l_next->l_prev = l; 3782 prev->l_next = l; 3783} 3784 3785static void 3786linkmap_delete(Obj_Entry *obj) 3787{ 3788 struct link_map *l = &obj->linkmap; 3789 3790 if (l->l_prev == NULL) { 3791 if ((r_debug.r_map = l->l_next) != NULL) 3792 l->l_next->l_prev = NULL; 3793 return; 3794 } 3795 3796 if ((l->l_prev->l_next = l->l_next) != NULL) 3797 l->l_next->l_prev = l->l_prev; 3798} 3799 3800/* 3801 * Function for the debugger to set a breakpoint on to gain control. 3802 * 3803 * The two parameters allow the debugger to easily find and determine 3804 * what the runtime loader is doing and to whom it is doing it. 3805 * 3806 * When the loadhook trap is hit (r_debug_state, set at program 3807 * initialization), the arguments can be found on the stack: 3808 * 3809 * +8 struct link_map *m 3810 * +4 struct r_debug *rd 3811 * +0 RetAddr 3812 */ 3813void 3814r_debug_state(struct r_debug* rd, struct link_map *m) 3815{ 3816 /* 3817 * The following is a hack to force the compiler to emit calls to 3818 * this function, even when optimizing. If the function is empty, 3819 * the compiler is not obliged to emit any code for calls to it, 3820 * even when marked __noinline. However, gdb depends on those 3821 * calls being made. 3822 */ 3823 __compiler_membar(); 3824} 3825 3826/* 3827 * A function called after init routines have completed. This can be used to 3828 * break before a program's entry routine is called, and can be used when 3829 * main is not available in the symbol table. 3830 */ 3831void 3832_r_debug_postinit(struct link_map *m) 3833{ 3834 3835 /* See r_debug_state(). */ 3836 __compiler_membar(); 3837} 3838 3839/* 3840 * Get address of the pointer variable in the main program. 3841 * Prefer non-weak symbol over the weak one. 3842 */ 3843static const void ** 3844get_program_var_addr(const char *name, RtldLockState *lockstate) 3845{ 3846 SymLook req; 3847 DoneList donelist; 3848 3849 symlook_init(&req, name); 3850 req.lockstate = lockstate; 3851 donelist_init(&donelist); 3852 if (symlook_global(&req, &donelist) != 0) 3853 return (NULL); 3854 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3855 return ((const void **)make_function_pointer(req.sym_out, 3856 req.defobj_out)); 3857 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3858 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3859 else 3860 return ((const void **)(req.defobj_out->relocbase + 3861 req.sym_out->st_value)); 3862} 3863 3864/* 3865 * Set a pointer variable in the main program to the given value. This 3866 * is used to set key variables such as "environ" before any of the 3867 * init functions are called. 3868 */ 3869static void 3870set_program_var(const char *name, const void *value) 3871{ 3872 const void **addr; 3873 3874 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3875 dbg("\"%s\": *%p <-- %p", name, addr, value); 3876 *addr = value; 3877 } 3878} 3879 3880/* 3881 * Search the global objects, including dependencies and main object, 3882 * for the given symbol. 3883 */ 3884static int 3885symlook_global(SymLook *req, DoneList *donelist) 3886{ 3887 SymLook req1; 3888 const Objlist_Entry *elm; 3889 int res; 3890 3891 symlook_init_from_req(&req1, req); 3892 3893 /* Search all objects loaded at program start up. */ 3894 if (req->defobj_out == NULL || 3895 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3896 res = symlook_list(&req1, &list_main, donelist); 3897 if (res == 0 && (req->defobj_out == NULL || 3898 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3899 req->sym_out = req1.sym_out; 3900 req->defobj_out = req1.defobj_out; 3901 assert(req->defobj_out != NULL); 3902 } 3903 } 3904 3905 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3906 STAILQ_FOREACH(elm, &list_global, link) { 3907 if (req->defobj_out != NULL && 3908 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3909 break; 3910 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3911 if (res == 0 && (req->defobj_out == NULL || 3912 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3913 req->sym_out = req1.sym_out; 3914 req->defobj_out = req1.defobj_out; 3915 assert(req->defobj_out != NULL); 3916 } 3917 } 3918 3919 return (req->sym_out != NULL ? 0 : ESRCH); 3920} 3921 3922/* 3923 * Given a symbol name in a referencing object, find the corresponding 3924 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3925 * no definition was found. Returns a pointer to the Obj_Entry of the 3926 * defining object via the reference parameter DEFOBJ_OUT. 3927 */ 3928static int 3929symlook_default(SymLook *req, const Obj_Entry *refobj) 3930{ 3931 DoneList donelist; 3932 const Objlist_Entry *elm; 3933 SymLook req1; 3934 int res; 3935 3936 donelist_init(&donelist); 3937 symlook_init_from_req(&req1, req); 3938 3939 /* Look first in the referencing object if linked symbolically. */ 3940 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3941 res = symlook_obj(&req1, refobj); 3942 if (res == 0) { 3943 req->sym_out = req1.sym_out; 3944 req->defobj_out = req1.defobj_out; 3945 assert(req->defobj_out != NULL); 3946 } 3947 } 3948 3949 symlook_global(req, &donelist); 3950 3951 /* Search all dlopened DAGs containing the referencing object. */ 3952 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3953 if (req->sym_out != NULL && 3954 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3955 break; 3956 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3957 if (res == 0 && (req->sym_out == NULL || 3958 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3959 req->sym_out = req1.sym_out; 3960 req->defobj_out = req1.defobj_out; 3961 assert(req->defobj_out != NULL); 3962 } 3963 } 3964 3965 /* 3966 * Search the dynamic linker itself, and possibly resolve the 3967 * symbol from there. This is how the application links to 3968 * dynamic linker services such as dlopen. 3969 */ 3970 if (req->sym_out == NULL || 3971 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3972 res = symlook_obj(&req1, &obj_rtld); 3973 if (res == 0) { 3974 req->sym_out = req1.sym_out; 3975 req->defobj_out = req1.defobj_out; 3976 assert(req->defobj_out != NULL); 3977 } 3978 } 3979 3980 return (req->sym_out != NULL ? 0 : ESRCH); 3981} 3982 3983static int 3984symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3985{ 3986 const Elf_Sym *def; 3987 const Obj_Entry *defobj; 3988 const Objlist_Entry *elm; 3989 SymLook req1; 3990 int res; 3991 3992 def = NULL; 3993 defobj = NULL; 3994 STAILQ_FOREACH(elm, objlist, link) { 3995 if (donelist_check(dlp, elm->obj)) 3996 continue; 3997 symlook_init_from_req(&req1, req); 3998 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3999 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4000 def = req1.sym_out; 4001 defobj = req1.defobj_out; 4002 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4003 break; 4004 } 4005 } 4006 } 4007 if (def != NULL) { 4008 req->sym_out = def; 4009 req->defobj_out = defobj; 4010 return (0); 4011 } 4012 return (ESRCH); 4013} 4014 4015/* 4016 * Search the chain of DAGS cointed to by the given Needed_Entry 4017 * for a symbol of the given name. Each DAG is scanned completely 4018 * before advancing to the next one. Returns a pointer to the symbol, 4019 * or NULL if no definition was found. 4020 */ 4021static int 4022symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 4023{ 4024 const Elf_Sym *def; 4025 const Needed_Entry *n; 4026 const Obj_Entry *defobj; 4027 SymLook req1; 4028 int res; 4029 4030 def = NULL; 4031 defobj = NULL; 4032 symlook_init_from_req(&req1, req); 4033 for (n = needed; n != NULL; n = n->next) { 4034 if (n->obj == NULL || 4035 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 4036 continue; 4037 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 4038 def = req1.sym_out; 4039 defobj = req1.defobj_out; 4040 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 4041 break; 4042 } 4043 } 4044 if (def != NULL) { 4045 req->sym_out = def; 4046 req->defobj_out = defobj; 4047 return (0); 4048 } 4049 return (ESRCH); 4050} 4051 4052/* 4053 * Search the symbol table of a single shared object for a symbol of 4054 * the given name and version, if requested. Returns a pointer to the 4055 * symbol, or NULL if no definition was found. If the object is 4056 * filter, return filtered symbol from filtee. 4057 * 4058 * The symbol's hash value is passed in for efficiency reasons; that 4059 * eliminates many recomputations of the hash value. 4060 */ 4061int 4062symlook_obj(SymLook *req, const Obj_Entry *obj) 4063{ 4064 DoneList donelist; 4065 SymLook req1; 4066 int flags, res, mres; 4067 4068 /* 4069 * If there is at least one valid hash at this point, we prefer to 4070 * use the faster GNU version if available. 4071 */ 4072 if (obj->valid_hash_gnu) 4073 mres = symlook_obj1_gnu(req, obj); 4074 else if (obj->valid_hash_sysv) 4075 mres = symlook_obj1_sysv(req, obj); 4076 else 4077 return (EINVAL); 4078 4079 if (mres == 0) { 4080 if (obj->needed_filtees != NULL) { 4081 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4082 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4083 donelist_init(&donelist); 4084 symlook_init_from_req(&req1, req); 4085 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 4086 if (res == 0) { 4087 req->sym_out = req1.sym_out; 4088 req->defobj_out = req1.defobj_out; 4089 } 4090 return (res); 4091 } 4092 if (obj->needed_aux_filtees != NULL) { 4093 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4094 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4095 donelist_init(&donelist); 4096 symlook_init_from_req(&req1, req); 4097 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4098 if (res == 0) { 4099 req->sym_out = req1.sym_out; 4100 req->defobj_out = req1.defobj_out; 4101 return (res); 4102 } 4103 } 4104 } 4105 return (mres); 4106} 4107 4108/* Symbol match routine common to both hash functions */ 4109static bool 4110matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4111 const unsigned long symnum) 4112{ 4113 Elf_Versym verndx; 4114 const Elf_Sym *symp; 4115 const char *strp; 4116 4117 symp = obj->symtab + symnum; 4118 strp = obj->strtab + symp->st_name; 4119 4120 switch (ELF_ST_TYPE(symp->st_info)) { 4121 case STT_FUNC: 4122 case STT_NOTYPE: 4123 case STT_OBJECT: 4124 case STT_COMMON: 4125 case STT_GNU_IFUNC: 4126 if (symp->st_value == 0) 4127 return (false); 4128 /* fallthrough */ 4129 case STT_TLS: 4130 if (symp->st_shndx != SHN_UNDEF) 4131 break; 4132#ifndef __mips__ 4133 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4134 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4135 break; 4136 /* fallthrough */ 4137#endif 4138 default: 4139 return (false); 4140 } 4141 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4142 return (false); 4143 4144 if (req->ventry == NULL) { 4145 if (obj->versyms != NULL) { 4146 verndx = VER_NDX(obj->versyms[symnum]); 4147 if (verndx > obj->vernum) { 4148 _rtld_error( 4149 "%s: symbol %s references wrong version %d", 4150 obj->path, obj->strtab + symnum, verndx); 4151 return (false); 4152 } 4153 /* 4154 * If we are not called from dlsym (i.e. this 4155 * is a normal relocation from unversioned 4156 * binary), accept the symbol immediately if 4157 * it happens to have first version after this 4158 * shared object became versioned. Otherwise, 4159 * if symbol is versioned and not hidden, 4160 * remember it. If it is the only symbol with 4161 * this name exported by the shared object, it 4162 * will be returned as a match by the calling 4163 * function. If symbol is global (verndx < 2) 4164 * accept it unconditionally. 4165 */ 4166 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4167 verndx == VER_NDX_GIVEN) { 4168 result->sym_out = symp; 4169 return (true); 4170 } 4171 else if (verndx >= VER_NDX_GIVEN) { 4172 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4173 == 0) { 4174 if (result->vsymp == NULL) 4175 result->vsymp = symp; 4176 result->vcount++; 4177 } 4178 return (false); 4179 } 4180 } 4181 result->sym_out = symp; 4182 return (true); 4183 } 4184 if (obj->versyms == NULL) { 4185 if (object_match_name(obj, req->ventry->name)) { 4186 _rtld_error("%s: object %s should provide version %s " 4187 "for symbol %s", obj_rtld.path, obj->path, 4188 req->ventry->name, obj->strtab + symnum); 4189 return (false); 4190 } 4191 } else { 4192 verndx = VER_NDX(obj->versyms[symnum]); 4193 if (verndx > obj->vernum) { 4194 _rtld_error("%s: symbol %s references wrong version %d", 4195 obj->path, obj->strtab + symnum, verndx); 4196 return (false); 4197 } 4198 if (obj->vertab[verndx].hash != req->ventry->hash || 4199 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4200 /* 4201 * Version does not match. Look if this is a 4202 * global symbol and if it is not hidden. If 4203 * global symbol (verndx < 2) is available, 4204 * use it. Do not return symbol if we are 4205 * called by dlvsym, because dlvsym looks for 4206 * a specific version and default one is not 4207 * what dlvsym wants. 4208 */ 4209 if ((req->flags & SYMLOOK_DLSYM) || 4210 (verndx >= VER_NDX_GIVEN) || 4211 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4212 return (false); 4213 } 4214 } 4215 result->sym_out = symp; 4216 return (true); 4217} 4218 4219/* 4220 * Search for symbol using SysV hash function. 4221 * obj->buckets is known not to be NULL at this point; the test for this was 4222 * performed with the obj->valid_hash_sysv assignment. 4223 */ 4224static int 4225symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4226{ 4227 unsigned long symnum; 4228 Sym_Match_Result matchres; 4229 4230 matchres.sym_out = NULL; 4231 matchres.vsymp = NULL; 4232 matchres.vcount = 0; 4233 4234 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4235 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4236 if (symnum >= obj->nchains) 4237 return (ESRCH); /* Bad object */ 4238 4239 if (matched_symbol(req, obj, &matchres, symnum)) { 4240 req->sym_out = matchres.sym_out; 4241 req->defobj_out = obj; 4242 return (0); 4243 } 4244 } 4245 if (matchres.vcount == 1) { 4246 req->sym_out = matchres.vsymp; 4247 req->defobj_out = obj; 4248 return (0); 4249 } 4250 return (ESRCH); 4251} 4252 4253/* Search for symbol using GNU hash function */ 4254static int 4255symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4256{ 4257 Elf_Addr bloom_word; 4258 const Elf32_Word *hashval; 4259 Elf32_Word bucket; 4260 Sym_Match_Result matchres; 4261 unsigned int h1, h2; 4262 unsigned long symnum; 4263 4264 matchres.sym_out = NULL; 4265 matchres.vsymp = NULL; 4266 matchres.vcount = 0; 4267 4268 /* Pick right bitmask word from Bloom filter array */ 4269 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4270 obj->maskwords_bm_gnu]; 4271 4272 /* Calculate modulus word size of gnu hash and its derivative */ 4273 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4274 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4275 4276 /* Filter out the "definitely not in set" queries */ 4277 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4278 return (ESRCH); 4279 4280 /* Locate hash chain and corresponding value element*/ 4281 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4282 if (bucket == 0) 4283 return (ESRCH); 4284 hashval = &obj->chain_zero_gnu[bucket]; 4285 do { 4286 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4287 symnum = hashval - obj->chain_zero_gnu; 4288 if (matched_symbol(req, obj, &matchres, symnum)) { 4289 req->sym_out = matchres.sym_out; 4290 req->defobj_out = obj; 4291 return (0); 4292 } 4293 } 4294 } while ((*hashval++ & 1) == 0); 4295 if (matchres.vcount == 1) { 4296 req->sym_out = matchres.vsymp; 4297 req->defobj_out = obj; 4298 return (0); 4299 } 4300 return (ESRCH); 4301} 4302 4303static void 4304trace_loaded_objects(Obj_Entry *obj) 4305{ 4306 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4307 int c; 4308 4309 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL) 4310 main_local = ""; 4311 4312 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL) 4313 fmt1 = "\t%o => %p (%x)\n"; 4314 4315 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL) 4316 fmt2 = "\t%o (%x)\n"; 4317 4318 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL")); 4319 4320 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4321 Needed_Entry *needed; 4322 char *name, *path; 4323 bool is_lib; 4324 4325 if (obj->marker) 4326 continue; 4327 if (list_containers && obj->needed != NULL) 4328 rtld_printf("%s:\n", obj->path); 4329 for (needed = obj->needed; needed; needed = needed->next) { 4330 if (needed->obj != NULL) { 4331 if (needed->obj->traced && !list_containers) 4332 continue; 4333 needed->obj->traced = true; 4334 path = needed->obj->path; 4335 } else 4336 path = "not found"; 4337 4338 name = (char *)obj->strtab + needed->name; 4339 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4340 4341 fmt = is_lib ? fmt1 : fmt2; 4342 while ((c = *fmt++) != '\0') { 4343 switch (c) { 4344 default: 4345 rtld_putchar(c); 4346 continue; 4347 case '\\': 4348 switch (c = *fmt) { 4349 case '\0': 4350 continue; 4351 case 'n': 4352 rtld_putchar('\n'); 4353 break; 4354 case 't': 4355 rtld_putchar('\t'); 4356 break; 4357 } 4358 break; 4359 case '%': 4360 switch (c = *fmt) { 4361 case '\0': 4362 continue; 4363 case '%': 4364 default: 4365 rtld_putchar(c); 4366 break; 4367 case 'A': 4368 rtld_putstr(main_local); 4369 break; 4370 case 'a': 4371 rtld_putstr(obj_main->path); 4372 break; 4373 case 'o': 4374 rtld_putstr(name); 4375 break; 4376#if 0 4377 case 'm': 4378 rtld_printf("%d", sodp->sod_major); 4379 break; 4380 case 'n': 4381 rtld_printf("%d", sodp->sod_minor); 4382 break; 4383#endif 4384 case 'p': 4385 rtld_putstr(path); 4386 break; 4387 case 'x': 4388 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4389 0); 4390 break; 4391 } 4392 break; 4393 } 4394 ++fmt; 4395 } 4396 } 4397 } 4398} 4399 4400/* 4401 * Unload a dlopened object and its dependencies from memory and from 4402 * our data structures. It is assumed that the DAG rooted in the 4403 * object has already been unreferenced, and that the object has a 4404 * reference count of 0. 4405 */ 4406static void 4407unload_object(Obj_Entry *root) 4408{ 4409 Obj_Entry *obj, *obj1; 4410 4411 assert(root->refcount == 0); 4412 4413 /* 4414 * Pass over the DAG removing unreferenced objects from 4415 * appropriate lists. 4416 */ 4417 unlink_object(root); 4418 4419 /* Unmap all objects that are no longer referenced. */ 4420 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4421 if (obj->marker || obj->refcount != 0) 4422 continue; 4423 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4424 obj->mapsize, 0, obj->path); 4425 dbg("unloading \"%s\"", obj->path); 4426 unload_filtees(root); 4427 munmap(obj->mapbase, obj->mapsize); 4428 linkmap_delete(obj); 4429 TAILQ_REMOVE(&obj_list, obj, next); 4430 obj_count--; 4431 obj_free(obj); 4432 } 4433} 4434 4435static void 4436unlink_object(Obj_Entry *root) 4437{ 4438 Objlist_Entry *elm; 4439 4440 if (root->refcount == 0) { 4441 /* Remove the object from the RTLD_GLOBAL list. */ 4442 objlist_remove(&list_global, root); 4443 4444 /* Remove the object from all objects' DAG lists. */ 4445 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4446 objlist_remove(&elm->obj->dldags, root); 4447 if (elm->obj != root) 4448 unlink_object(elm->obj); 4449 } 4450 } 4451} 4452 4453static void 4454ref_dag(Obj_Entry *root) 4455{ 4456 Objlist_Entry *elm; 4457 4458 assert(root->dag_inited); 4459 STAILQ_FOREACH(elm, &root->dagmembers, link) 4460 elm->obj->refcount++; 4461} 4462 4463static void 4464unref_dag(Obj_Entry *root) 4465{ 4466 Objlist_Entry *elm; 4467 4468 assert(root->dag_inited); 4469 STAILQ_FOREACH(elm, &root->dagmembers, link) 4470 elm->obj->refcount--; 4471} 4472 4473/* 4474 * Common code for MD __tls_get_addr(). 4475 */ 4476static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4477static void * 4478tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4479{ 4480 Elf_Addr *newdtv, *dtv; 4481 RtldLockState lockstate; 4482 int to_copy; 4483 4484 dtv = *dtvp; 4485 /* Check dtv generation in case new modules have arrived */ 4486 if (dtv[0] != tls_dtv_generation) { 4487 wlock_acquire(rtld_bind_lock, &lockstate); 4488 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4489 to_copy = dtv[1]; 4490 if (to_copy > tls_max_index) 4491 to_copy = tls_max_index; 4492 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4493 newdtv[0] = tls_dtv_generation; 4494 newdtv[1] = tls_max_index; 4495 free(dtv); 4496 lock_release(rtld_bind_lock, &lockstate); 4497 dtv = *dtvp = newdtv; 4498 } 4499 4500 /* Dynamically allocate module TLS if necessary */ 4501 if (dtv[index + 1] == 0) { 4502 /* Signal safe, wlock will block out signals. */ 4503 wlock_acquire(rtld_bind_lock, &lockstate); 4504 if (!dtv[index + 1]) 4505 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4506 lock_release(rtld_bind_lock, &lockstate); 4507 } 4508 return ((void *)(dtv[index + 1] + offset)); 4509} 4510 4511void * 4512tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4513{ 4514 Elf_Addr *dtv; 4515 4516 dtv = *dtvp; 4517 /* Check dtv generation in case new modules have arrived */ 4518 if (__predict_true(dtv[0] == tls_dtv_generation && 4519 dtv[index + 1] != 0)) 4520 return ((void *)(dtv[index + 1] + offset)); 4521 return (tls_get_addr_slow(dtvp, index, offset)); 4522} 4523 4524#if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4525 defined(__powerpc__) || defined(__riscv__) 4526 4527/* 4528 * Allocate Static TLS using the Variant I method. 4529 */ 4530void * 4531allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4532{ 4533 Obj_Entry *obj; 4534 char *tcb; 4535 Elf_Addr **tls; 4536 Elf_Addr *dtv; 4537 Elf_Addr addr; 4538 int i; 4539 4540 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4541 return (oldtcb); 4542 4543 assert(tcbsize >= TLS_TCB_SIZE); 4544 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4545 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4546 4547 if (oldtcb != NULL) { 4548 memcpy(tls, oldtcb, tls_static_space); 4549 free(oldtcb); 4550 4551 /* Adjust the DTV. */ 4552 dtv = tls[0]; 4553 for (i = 0; i < dtv[1]; i++) { 4554 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4555 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4556 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4557 } 4558 } 4559 } else { 4560 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4561 tls[0] = dtv; 4562 dtv[0] = tls_dtv_generation; 4563 dtv[1] = tls_max_index; 4564 4565 for (obj = globallist_curr(objs); obj != NULL; 4566 obj = globallist_next(obj)) { 4567 if (obj->tlsoffset > 0) { 4568 addr = (Elf_Addr)tls + obj->tlsoffset; 4569 if (obj->tlsinitsize > 0) 4570 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4571 if (obj->tlssize > obj->tlsinitsize) 4572 memset((void*) (addr + obj->tlsinitsize), 0, 4573 obj->tlssize - obj->tlsinitsize); 4574 dtv[obj->tlsindex + 1] = addr; 4575 } 4576 } 4577 } 4578 4579 return (tcb); 4580} 4581 4582void 4583free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4584{ 4585 Elf_Addr *dtv; 4586 Elf_Addr tlsstart, tlsend; 4587 int dtvsize, i; 4588 4589 assert(tcbsize >= TLS_TCB_SIZE); 4590 4591 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4592 tlsend = tlsstart + tls_static_space; 4593 4594 dtv = *(Elf_Addr **)tlsstart; 4595 dtvsize = dtv[1]; 4596 for (i = 0; i < dtvsize; i++) { 4597 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4598 free((void*)dtv[i+2]); 4599 } 4600 } 4601 free(dtv); 4602 free(tcb); 4603} 4604 4605#endif 4606 4607#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4608 4609/* 4610 * Allocate Static TLS using the Variant II method. 4611 */ 4612void * 4613allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4614{ 4615 Obj_Entry *obj; 4616 size_t size, ralign; 4617 char *tls; 4618 Elf_Addr *dtv, *olddtv; 4619 Elf_Addr segbase, oldsegbase, addr; 4620 int i; 4621 4622 ralign = tcbalign; 4623 if (tls_static_max_align > ralign) 4624 ralign = tls_static_max_align; 4625 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4626 4627 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4628 tls = malloc_aligned(size, ralign); 4629 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4630 4631 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4632 ((Elf_Addr*)segbase)[0] = segbase; 4633 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4634 4635 dtv[0] = tls_dtv_generation; 4636 dtv[1] = tls_max_index; 4637 4638 if (oldtls) { 4639 /* 4640 * Copy the static TLS block over whole. 4641 */ 4642 oldsegbase = (Elf_Addr) oldtls; 4643 memcpy((void *)(segbase - tls_static_space), 4644 (const void *)(oldsegbase - tls_static_space), 4645 tls_static_space); 4646 4647 /* 4648 * If any dynamic TLS blocks have been created tls_get_addr(), 4649 * move them over. 4650 */ 4651 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4652 for (i = 0; i < olddtv[1]; i++) { 4653 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4654 dtv[i+2] = olddtv[i+2]; 4655 olddtv[i+2] = 0; 4656 } 4657 } 4658 4659 /* 4660 * We assume that this block was the one we created with 4661 * allocate_initial_tls(). 4662 */ 4663 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4664 } else { 4665 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4666 if (obj->marker || obj->tlsoffset == 0) 4667 continue; 4668 addr = segbase - obj->tlsoffset; 4669 memset((void*) (addr + obj->tlsinitsize), 4670 0, obj->tlssize - obj->tlsinitsize); 4671 if (obj->tlsinit) 4672 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4673 dtv[obj->tlsindex + 1] = addr; 4674 } 4675 } 4676 4677 return (void*) segbase; 4678} 4679 4680void 4681free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4682{ 4683 Elf_Addr* dtv; 4684 size_t size, ralign; 4685 int dtvsize, i; 4686 Elf_Addr tlsstart, tlsend; 4687 4688 /* 4689 * Figure out the size of the initial TLS block so that we can 4690 * find stuff which ___tls_get_addr() allocated dynamically. 4691 */ 4692 ralign = tcbalign; 4693 if (tls_static_max_align > ralign) 4694 ralign = tls_static_max_align; 4695 size = round(tls_static_space, ralign); 4696 4697 dtv = ((Elf_Addr**)tls)[1]; 4698 dtvsize = dtv[1]; 4699 tlsend = (Elf_Addr) tls; 4700 tlsstart = tlsend - size; 4701 for (i = 0; i < dtvsize; i++) { 4702 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4703 free_aligned((void *)dtv[i + 2]); 4704 } 4705 } 4706 4707 free_aligned((void *)tlsstart); 4708 free((void*) dtv); 4709} 4710 4711#endif 4712 4713/* 4714 * Allocate TLS block for module with given index. 4715 */ 4716void * 4717allocate_module_tls(int index) 4718{ 4719 Obj_Entry* obj; 4720 char* p; 4721 4722 TAILQ_FOREACH(obj, &obj_list, next) { 4723 if (obj->marker) 4724 continue; 4725 if (obj->tlsindex == index) 4726 break; 4727 } 4728 if (!obj) { 4729 _rtld_error("Can't find module with TLS index %d", index); 4730 rtld_die(); 4731 } 4732 4733 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4734 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4735 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4736 4737 return p; 4738} 4739 4740bool 4741allocate_tls_offset(Obj_Entry *obj) 4742{ 4743 size_t off; 4744 4745 if (obj->tls_done) 4746 return true; 4747 4748 if (obj->tlssize == 0) { 4749 obj->tls_done = true; 4750 return true; 4751 } 4752 4753 if (tls_last_offset == 0) 4754 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4755 else 4756 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4757 obj->tlssize, obj->tlsalign); 4758 4759 /* 4760 * If we have already fixed the size of the static TLS block, we 4761 * must stay within that size. When allocating the static TLS, we 4762 * leave a small amount of space spare to be used for dynamically 4763 * loading modules which use static TLS. 4764 */ 4765 if (tls_static_space != 0) { 4766 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4767 return false; 4768 } else if (obj->tlsalign > tls_static_max_align) { 4769 tls_static_max_align = obj->tlsalign; 4770 } 4771 4772 tls_last_offset = obj->tlsoffset = off; 4773 tls_last_size = obj->tlssize; 4774 obj->tls_done = true; 4775 4776 return true; 4777} 4778 4779void 4780free_tls_offset(Obj_Entry *obj) 4781{ 4782 4783 /* 4784 * If we were the last thing to allocate out of the static TLS 4785 * block, we give our space back to the 'allocator'. This is a 4786 * simplistic workaround to allow libGL.so.1 to be loaded and 4787 * unloaded multiple times. 4788 */ 4789 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4790 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4791 tls_last_offset -= obj->tlssize; 4792 tls_last_size = 0; 4793 } 4794} 4795 4796void * 4797_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4798{ 4799 void *ret; 4800 RtldLockState lockstate; 4801 4802 wlock_acquire(rtld_bind_lock, &lockstate); 4803 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4804 tcbsize, tcbalign); 4805 lock_release(rtld_bind_lock, &lockstate); 4806 return (ret); 4807} 4808 4809void 4810_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4811{ 4812 RtldLockState lockstate; 4813 4814 wlock_acquire(rtld_bind_lock, &lockstate); 4815 free_tls(tcb, tcbsize, tcbalign); 4816 lock_release(rtld_bind_lock, &lockstate); 4817} 4818 4819static void 4820object_add_name(Obj_Entry *obj, const char *name) 4821{ 4822 Name_Entry *entry; 4823 size_t len; 4824 4825 len = strlen(name); 4826 entry = malloc(sizeof(Name_Entry) + len); 4827 4828 if (entry != NULL) { 4829 strcpy(entry->name, name); 4830 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4831 } 4832} 4833 4834static int 4835object_match_name(const Obj_Entry *obj, const char *name) 4836{ 4837 Name_Entry *entry; 4838 4839 STAILQ_FOREACH(entry, &obj->names, link) { 4840 if (strcmp(name, entry->name) == 0) 4841 return (1); 4842 } 4843 return (0); 4844} 4845 4846static Obj_Entry * 4847locate_dependency(const Obj_Entry *obj, const char *name) 4848{ 4849 const Objlist_Entry *entry; 4850 const Needed_Entry *needed; 4851 4852 STAILQ_FOREACH(entry, &list_main, link) { 4853 if (object_match_name(entry->obj, name)) 4854 return entry->obj; 4855 } 4856 4857 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4858 if (strcmp(obj->strtab + needed->name, name) == 0 || 4859 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4860 /* 4861 * If there is DT_NEEDED for the name we are looking for, 4862 * we are all set. Note that object might not be found if 4863 * dependency was not loaded yet, so the function can 4864 * return NULL here. This is expected and handled 4865 * properly by the caller. 4866 */ 4867 return (needed->obj); 4868 } 4869 } 4870 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4871 obj->path, name); 4872 rtld_die(); 4873} 4874 4875static int 4876check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4877 const Elf_Vernaux *vna) 4878{ 4879 const Elf_Verdef *vd; 4880 const char *vername; 4881 4882 vername = refobj->strtab + vna->vna_name; 4883 vd = depobj->verdef; 4884 if (vd == NULL) { 4885 _rtld_error("%s: version %s required by %s not defined", 4886 depobj->path, vername, refobj->path); 4887 return (-1); 4888 } 4889 for (;;) { 4890 if (vd->vd_version != VER_DEF_CURRENT) { 4891 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4892 depobj->path, vd->vd_version); 4893 return (-1); 4894 } 4895 if (vna->vna_hash == vd->vd_hash) { 4896 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4897 ((char *)vd + vd->vd_aux); 4898 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4899 return (0); 4900 } 4901 if (vd->vd_next == 0) 4902 break; 4903 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4904 } 4905 if (vna->vna_flags & VER_FLG_WEAK) 4906 return (0); 4907 _rtld_error("%s: version %s required by %s not found", 4908 depobj->path, vername, refobj->path); 4909 return (-1); 4910} 4911 4912static int 4913rtld_verify_object_versions(Obj_Entry *obj) 4914{ 4915 const Elf_Verneed *vn; 4916 const Elf_Verdef *vd; 4917 const Elf_Verdaux *vda; 4918 const Elf_Vernaux *vna; 4919 const Obj_Entry *depobj; 4920 int maxvernum, vernum; 4921 4922 if (obj->ver_checked) 4923 return (0); 4924 obj->ver_checked = true; 4925 4926 maxvernum = 0; 4927 /* 4928 * Walk over defined and required version records and figure out 4929 * max index used by any of them. Do very basic sanity checking 4930 * while there. 4931 */ 4932 vn = obj->verneed; 4933 while (vn != NULL) { 4934 if (vn->vn_version != VER_NEED_CURRENT) { 4935 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4936 obj->path, vn->vn_version); 4937 return (-1); 4938 } 4939 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4940 for (;;) { 4941 vernum = VER_NEED_IDX(vna->vna_other); 4942 if (vernum > maxvernum) 4943 maxvernum = vernum; 4944 if (vna->vna_next == 0) 4945 break; 4946 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4947 } 4948 if (vn->vn_next == 0) 4949 break; 4950 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4951 } 4952 4953 vd = obj->verdef; 4954 while (vd != NULL) { 4955 if (vd->vd_version != VER_DEF_CURRENT) { 4956 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4957 obj->path, vd->vd_version); 4958 return (-1); 4959 } 4960 vernum = VER_DEF_IDX(vd->vd_ndx); 4961 if (vernum > maxvernum) 4962 maxvernum = vernum; 4963 if (vd->vd_next == 0) 4964 break; 4965 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4966 } 4967 4968 if (maxvernum == 0) 4969 return (0); 4970 4971 /* 4972 * Store version information in array indexable by version index. 4973 * Verify that object version requirements are satisfied along the 4974 * way. 4975 */ 4976 obj->vernum = maxvernum + 1; 4977 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4978 4979 vd = obj->verdef; 4980 while (vd != NULL) { 4981 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4982 vernum = VER_DEF_IDX(vd->vd_ndx); 4983 assert(vernum <= maxvernum); 4984 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4985 obj->vertab[vernum].hash = vd->vd_hash; 4986 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4987 obj->vertab[vernum].file = NULL; 4988 obj->vertab[vernum].flags = 0; 4989 } 4990 if (vd->vd_next == 0) 4991 break; 4992 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4993 } 4994 4995 vn = obj->verneed; 4996 while (vn != NULL) { 4997 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4998 if (depobj == NULL) 4999 return (-1); 5000 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 5001 for (;;) { 5002 if (check_object_provided_version(obj, depobj, vna)) 5003 return (-1); 5004 vernum = VER_NEED_IDX(vna->vna_other); 5005 assert(vernum <= maxvernum); 5006 obj->vertab[vernum].hash = vna->vna_hash; 5007 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 5008 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 5009 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 5010 VER_INFO_HIDDEN : 0; 5011 if (vna->vna_next == 0) 5012 break; 5013 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 5014 } 5015 if (vn->vn_next == 0) 5016 break; 5017 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 5018 } 5019 return 0; 5020} 5021 5022static int 5023rtld_verify_versions(const Objlist *objlist) 5024{ 5025 Objlist_Entry *entry; 5026 int rc; 5027 5028 rc = 0; 5029 STAILQ_FOREACH(entry, objlist, link) { 5030 /* 5031 * Skip dummy objects or objects that have their version requirements 5032 * already checked. 5033 */ 5034 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 5035 continue; 5036 if (rtld_verify_object_versions(entry->obj) == -1) { 5037 rc = -1; 5038 if (ld_tracing == NULL) 5039 break; 5040 } 5041 } 5042 if (rc == 0 || ld_tracing != NULL) 5043 rc = rtld_verify_object_versions(&obj_rtld); 5044 return rc; 5045} 5046 5047const Ver_Entry * 5048fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 5049{ 5050 Elf_Versym vernum; 5051 5052 if (obj->vertab) { 5053 vernum = VER_NDX(obj->versyms[symnum]); 5054 if (vernum >= obj->vernum) { 5055 _rtld_error("%s: symbol %s has wrong verneed value %d", 5056 obj->path, obj->strtab + symnum, vernum); 5057 } else if (obj->vertab[vernum].hash != 0) { 5058 return &obj->vertab[vernum]; 5059 } 5060 } 5061 return NULL; 5062} 5063 5064int 5065_rtld_get_stack_prot(void) 5066{ 5067 5068 return (stack_prot); 5069} 5070 5071int 5072_rtld_is_dlopened(void *arg) 5073{ 5074 Obj_Entry *obj; 5075 RtldLockState lockstate; 5076 int res; 5077 5078 rlock_acquire(rtld_bind_lock, &lockstate); 5079 obj = dlcheck(arg); 5080 if (obj == NULL) 5081 obj = obj_from_addr(arg); 5082 if (obj == NULL) { 5083 _rtld_error("No shared object contains address"); 5084 lock_release(rtld_bind_lock, &lockstate); 5085 return (-1); 5086 } 5087 res = obj->dlopened ? 1 : 0; 5088 lock_release(rtld_bind_lock, &lockstate); 5089 return (res); 5090} 5091 5092static void 5093map_stacks_exec(RtldLockState *lockstate) 5094{ 5095 void (*thr_map_stacks_exec)(void); 5096 5097 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5098 return; 5099 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5100 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5101 if (thr_map_stacks_exec != NULL) { 5102 stack_prot |= PROT_EXEC; 5103 thr_map_stacks_exec(); 5104 } 5105} 5106 5107void 5108symlook_init(SymLook *dst, const char *name) 5109{ 5110 5111 bzero(dst, sizeof(*dst)); 5112 dst->name = name; 5113 dst->hash = elf_hash(name); 5114 dst->hash_gnu = gnu_hash(name); 5115} 5116 5117static void 5118symlook_init_from_req(SymLook *dst, const SymLook *src) 5119{ 5120 5121 dst->name = src->name; 5122 dst->hash = src->hash; 5123 dst->hash_gnu = src->hash_gnu; 5124 dst->ventry = src->ventry; 5125 dst->flags = src->flags; 5126 dst->defobj_out = NULL; 5127 dst->sym_out = NULL; 5128 dst->lockstate = src->lockstate; 5129} 5130 5131 5132/* 5133 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 5134 */ 5135static int 5136parse_libdir(const char *str) 5137{ 5138 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5139 const char *orig; 5140 int fd; 5141 char c; 5142 5143 orig = str; 5144 fd = 0; 5145 for (c = *str; c != '\0'; c = *++str) { 5146 if (c < '0' || c > '9') 5147 return (-1); 5148 5149 fd *= RADIX; 5150 fd += c - '0'; 5151 } 5152 5153 /* Make sure we actually parsed something. */ 5154 if (str == orig) { 5155 _rtld_error("failed to parse directory FD from '%s'", str); 5156 return (-1); 5157 } 5158 return (fd); 5159} 5160 5161/* 5162 * Overrides for libc_pic-provided functions. 5163 */ 5164 5165int 5166__getosreldate(void) 5167{ 5168 size_t len; 5169 int oid[2]; 5170 int error, osrel; 5171 5172 if (osreldate != 0) 5173 return (osreldate); 5174 5175 oid[0] = CTL_KERN; 5176 oid[1] = KERN_OSRELDATE; 5177 osrel = 0; 5178 len = sizeof(osrel); 5179 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5180 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5181 osreldate = osrel; 5182 return (osreldate); 5183} 5184 5185void 5186exit(int status) 5187{ 5188 5189 _exit(status); 5190} 5191 5192void (*__cleanup)(void); 5193int __isthreaded = 0; 5194int _thread_autoinit_dummy_decl = 1; 5195 5196/* 5197 * No unresolved symbols for rtld. 5198 */ 5199void 5200__pthread_cxa_finalize(struct dl_phdr_info *a) 5201{ 5202} 5203 5204void 5205__stack_chk_fail(void) 5206{ 5207 5208 _rtld_error("stack overflow detected; terminated"); 5209 rtld_die(); 5210} 5211__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5212 5213void 5214__chk_fail(void) 5215{ 5216 5217 _rtld_error("buffer overflow detected; terminated"); 5218 rtld_die(); 5219} 5220 5221const char * 5222rtld_strerror(int errnum) 5223{ 5224 5225 if (errnum < 0 || errnum >= sys_nerr) 5226 return ("Unknown error"); 5227 return (sys_errlist[errnum]); 5228} 5229