rtld.c revision 310238
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: stable/10/libexec/rtld-elf/rtld.c 310238 2016-12-19 00:28:04Z 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 "rtld_tls.h" 60#include "rtld_printf.h" 61#include "notes.h" 62 63#ifndef COMPAT_32BIT 64#define PATH_RTLD "/libexec/ld-elf.so.1" 65#else 66#define PATH_RTLD "/libexec/ld-elf32.so.1" 67#endif 68 69/* Types. */ 70typedef void (*func_ptr_type)(); 71typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73/* 74 * Function declarations. 75 */ 76static const char *basename(const char *); 77static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 78 const Elf_Dyn **, const Elf_Dyn **); 79static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 80 const Elf_Dyn *); 81static void digest_dynamic(Obj_Entry *, int); 82static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 83static Obj_Entry *dlcheck(void *); 84static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 85 int lo_flags, int mode, RtldLockState *lockstate); 86static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 87static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 88static bool donelist_check(DoneList *, const Obj_Entry *); 89static void errmsg_restore(char *); 90static char *errmsg_save(void); 91static void *fill_search_info(const char *, size_t, void *); 92static char *find_library(const char *, const Obj_Entry *); 93static const char *gethints(bool); 94static void init_dag(Obj_Entry *); 95static void init_pagesizes(Elf_Auxinfo **aux_info); 96static void init_rtld(caddr_t, Elf_Auxinfo **); 97static void initlist_add_neededs(Needed_Entry *, Objlist *); 98static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 99static void linkmap_add(Obj_Entry *); 100static void linkmap_delete(Obj_Entry *); 101static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 102static void unload_filtees(Obj_Entry *); 103static int load_needed_objects(Obj_Entry *, int); 104static int load_preload_objects(void); 105static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 106static void map_stacks_exec(RtldLockState *); 107static Obj_Entry *obj_from_addr(const void *); 108static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 109static void objlist_call_init(Objlist *, RtldLockState *); 110static void objlist_clear(Objlist *); 111static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 112static void objlist_init(Objlist *); 113static void objlist_push_head(Objlist *, Obj_Entry *); 114static void objlist_push_tail(Objlist *, Obj_Entry *); 115static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 116static void objlist_remove(Objlist *, Obj_Entry *); 117static void *path_enumerate(const char *, path_enum_proc, void *); 118static int relocate_object_dag(Obj_Entry *root, bool bind_now, 119 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 120static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 121 int flags, RtldLockState *lockstate); 122static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 123 RtldLockState *); 124static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 125 int flags, RtldLockState *lockstate); 126static int rtld_dirname(const char *, char *); 127static int rtld_dirname_abs(const char *, char *); 128static void *rtld_dlopen(const char *name, int fd, int mode); 129static void rtld_exit(void); 130static char *search_library_path(const char *, const char *); 131static const void **get_program_var_addr(const char *, RtldLockState *); 132static void set_program_var(const char *, const void *); 133static int symlook_default(SymLook *, const Obj_Entry *refobj); 134static int symlook_global(SymLook *, DoneList *); 135static void symlook_init_from_req(SymLook *, const SymLook *); 136static int symlook_list(SymLook *, const Objlist *, DoneList *); 137static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 138static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 139static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 140static void trace_loaded_objects(Obj_Entry *); 141static void unlink_object(Obj_Entry *); 142static void unload_object(Obj_Entry *); 143static void unref_dag(Obj_Entry *); 144static void ref_dag(Obj_Entry *); 145static char *origin_subst_one(Obj_Entry *, char *, const char *, 146 const char *, bool); 147static char *origin_subst(Obj_Entry *, char *); 148static bool obj_resolve_origin(Obj_Entry *obj); 149static void preinit_main(void); 150static int rtld_verify_versions(const Objlist *); 151static int rtld_verify_object_versions(Obj_Entry *); 152static void object_add_name(Obj_Entry *, const char *); 153static int object_match_name(const Obj_Entry *, const char *); 154static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 155static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 156 struct dl_phdr_info *phdr_info); 157static uint32_t gnu_hash(const char *); 158static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 159 const unsigned long); 160 161void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 162void _r_debug_postinit(struct link_map *) __noinline __exported; 163 164/* 165 * Data declarations. 166 */ 167static char *error_message; /* Message for dlerror(), or NULL */ 168struct r_debug r_debug __exported; /* for GDB; */ 169static bool libmap_disable; /* Disable libmap */ 170static bool ld_loadfltr; /* Immediate filters processing */ 171static char *libmap_override; /* Maps to use in addition to libmap.conf */ 172static bool trust; /* False for setuid and setgid programs */ 173static bool dangerous_ld_env; /* True if environment variables have been 174 used to affect the libraries loaded */ 175static char *ld_bind_now; /* Environment variable for immediate binding */ 176static char *ld_debug; /* Environment variable for debugging */ 177static char *ld_library_path; /* Environment variable for search path */ 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 * Fill in a DoneList with an allocation large enough to hold all of 258 * the currently-loaded objects. Keep this as a macro since it calls 259 * alloca and we want that to occur within the scope of the caller. 260 */ 261#define donelist_init(dlp) \ 262 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 263 assert((dlp)->objs != NULL), \ 264 (dlp)->num_alloc = obj_count, \ 265 (dlp)->num_used = 0) 266 267#define UTRACE_DLOPEN_START 1 268#define UTRACE_DLOPEN_STOP 2 269#define UTRACE_DLCLOSE_START 3 270#define UTRACE_DLCLOSE_STOP 4 271#define UTRACE_LOAD_OBJECT 5 272#define UTRACE_UNLOAD_OBJECT 6 273#define UTRACE_ADD_RUNDEP 7 274#define UTRACE_PRELOAD_FINISHED 8 275#define UTRACE_INIT_CALL 9 276#define UTRACE_FINI_CALL 10 277#define UTRACE_DLSYM_START 11 278#define UTRACE_DLSYM_STOP 12 279 280struct utrace_rtld { 281 char sig[4]; /* 'RTLD' */ 282 int event; 283 void *handle; 284 void *mapbase; /* Used for 'parent' and 'init/fini' */ 285 size_t mapsize; 286 int refcnt; /* Used for 'mode' */ 287 char name[MAXPATHLEN]; 288}; 289 290#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 291 if (ld_utrace != NULL) \ 292 ld_utrace_log(e, h, mb, ms, r, n); \ 293} while (0) 294 295static void 296ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 297 int refcnt, const char *name) 298{ 299 struct utrace_rtld ut; 300 301 ut.sig[0] = 'R'; 302 ut.sig[1] = 'T'; 303 ut.sig[2] = 'L'; 304 ut.sig[3] = 'D'; 305 ut.event = event; 306 ut.handle = handle; 307 ut.mapbase = mapbase; 308 ut.mapsize = mapsize; 309 ut.refcnt = refcnt; 310 bzero(ut.name, sizeof(ut.name)); 311 if (name) 312 strlcpy(ut.name, name, sizeof(ut.name)); 313 utrace(&ut, sizeof(ut)); 314} 315 316/* 317 * Main entry point for dynamic linking. The first argument is the 318 * stack pointer. The stack is expected to be laid out as described 319 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 320 * Specifically, the stack pointer points to a word containing 321 * ARGC. Following that in the stack is a null-terminated sequence 322 * of pointers to argument strings. Then comes a null-terminated 323 * sequence of pointers to environment strings. Finally, there is a 324 * sequence of "auxiliary vector" entries. 325 * 326 * The second argument points to a place to store the dynamic linker's 327 * exit procedure pointer and the third to a place to store the main 328 * program's object. 329 * 330 * The return value is the main program's entry point. 331 */ 332func_ptr_type 333_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 334{ 335 Elf_Auxinfo *aux_info[AT_COUNT]; 336 int i; 337 int argc; 338 char **argv; 339 char **env; 340 Elf_Auxinfo *aux; 341 Elf_Auxinfo *auxp; 342 const char *argv0; 343 Objlist_Entry *entry; 344 Obj_Entry *obj; 345 Obj_Entry *preload_tail; 346 Obj_Entry *last_interposer; 347 Objlist initlist; 348 RtldLockState lockstate; 349 char *library_path_rpath; 350 int mib[2]; 351 size_t len; 352 353 /* 354 * On entry, the dynamic linker itself has not been relocated yet. 355 * Be very careful not to reference any global data until after 356 * init_rtld has returned. It is OK to reference file-scope statics 357 * and string constants, and to call static and global functions. 358 */ 359 360 /* Find the auxiliary vector on the stack. */ 361 argc = *sp++; 362 argv = (char **) sp; 363 sp += argc + 1; /* Skip over arguments and NULL terminator */ 364 env = (char **) sp; 365 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 366 ; 367 aux = (Elf_Auxinfo *) sp; 368 369 /* Digest the auxiliary vector. */ 370 for (i = 0; i < AT_COUNT; i++) 371 aux_info[i] = NULL; 372 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 373 if (auxp->a_type < AT_COUNT) 374 aux_info[auxp->a_type] = auxp; 375 } 376 377 /* Initialize and relocate ourselves. */ 378 assert(aux_info[AT_BASE] != NULL); 379 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 380 381 __progname = obj_rtld.path; 382 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 383 environ = env; 384 main_argc = argc; 385 main_argv = argv; 386 387 if (aux_info[AT_CANARY] != NULL && 388 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 389 i = aux_info[AT_CANARYLEN]->a_un.a_val; 390 if (i > sizeof(__stack_chk_guard)) 391 i = sizeof(__stack_chk_guard); 392 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 393 } else { 394 mib[0] = CTL_KERN; 395 mib[1] = KERN_ARND; 396 397 len = sizeof(__stack_chk_guard); 398 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 399 len != sizeof(__stack_chk_guard)) { 400 /* If sysctl was unsuccessful, use the "terminator canary". */ 401 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 402 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 403 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 404 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 405 } 406 } 407 408 trust = !issetugid(); 409 410 ld_bind_now = getenv(LD_ "BIND_NOW"); 411 /* 412 * If the process is tainted, then we un-set the dangerous environment 413 * variables. The process will be marked as tainted until setuid(2) 414 * is called. If any child process calls setuid(2) we do not want any 415 * future processes to honor the potentially un-safe variables. 416 */ 417 if (!trust) { 418 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 419 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 420 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 421 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 422 _rtld_error("environment corrupt; aborting"); 423 rtld_die(); 424 } 425 } 426 ld_debug = getenv(LD_ "DEBUG"); 427 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 428 libmap_override = getenv(LD_ "LIBMAP"); 429 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 430 ld_preload = getenv(LD_ "PRELOAD"); 431 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 432 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 433 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 434 if (library_path_rpath != NULL) { 435 if (library_path_rpath[0] == 'y' || 436 library_path_rpath[0] == 'Y' || 437 library_path_rpath[0] == '1') 438 ld_library_path_rpath = true; 439 else 440 ld_library_path_rpath = false; 441 } 442 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 443 (ld_library_path != NULL) || (ld_preload != NULL) || 444 (ld_elf_hints_path != NULL) || ld_loadfltr; 445 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 446 ld_utrace = getenv(LD_ "UTRACE"); 447 448 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 449 ld_elf_hints_path = _PATH_ELF_HINTS; 450 451 if (ld_debug != NULL && *ld_debug != '\0') 452 debug = 1; 453 dbg("%s is initialized, base address = %p", __progname, 454 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 455 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 456 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 457 458 dbg("initializing thread locks"); 459 lockdflt_init(); 460 461 /* 462 * Load the main program, or process its program header if it is 463 * already loaded. 464 */ 465 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 466 int fd = aux_info[AT_EXECFD]->a_un.a_val; 467 dbg("loading main program"); 468 obj_main = map_object(fd, argv0, NULL); 469 close(fd); 470 if (obj_main == NULL) 471 rtld_die(); 472 max_stack_flags = obj->stack_flags; 473 } else { /* Main program already loaded. */ 474 const Elf_Phdr *phdr; 475 int phnum; 476 caddr_t entry; 477 478 dbg("processing main program's program header"); 479 assert(aux_info[AT_PHDR] != NULL); 480 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 481 assert(aux_info[AT_PHNUM] != NULL); 482 phnum = aux_info[AT_PHNUM]->a_un.a_val; 483 assert(aux_info[AT_PHENT] != NULL); 484 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 485 assert(aux_info[AT_ENTRY] != NULL); 486 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 487 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 488 rtld_die(); 489 } 490 491 if (aux_info[AT_EXECPATH] != 0) { 492 char *kexecpath; 493 char buf[MAXPATHLEN]; 494 495 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 496 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 497 if (kexecpath[0] == '/') 498 obj_main->path = kexecpath; 499 else if (getcwd(buf, sizeof(buf)) == NULL || 500 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 501 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 502 obj_main->path = xstrdup(argv0); 503 else 504 obj_main->path = xstrdup(buf); 505 } else { 506 dbg("No AT_EXECPATH"); 507 obj_main->path = xstrdup(argv0); 508 } 509 dbg("obj_main path %s", obj_main->path); 510 obj_main->mainprog = true; 511 512 if (aux_info[AT_STACKPROT] != NULL && 513 aux_info[AT_STACKPROT]->a_un.a_val != 0) 514 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 515 516#ifndef COMPAT_32BIT 517 /* 518 * Get the actual dynamic linker pathname from the executable if 519 * possible. (It should always be possible.) That ensures that 520 * gdb will find the right dynamic linker even if a non-standard 521 * one is being used. 522 */ 523 if (obj_main->interp != NULL && 524 strcmp(obj_main->interp, obj_rtld.path) != 0) { 525 free(obj_rtld.path); 526 obj_rtld.path = xstrdup(obj_main->interp); 527 __progname = obj_rtld.path; 528 } 529#endif 530 531 digest_dynamic(obj_main, 0); 532 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 533 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 534 obj_main->dynsymcount); 535 536 linkmap_add(obj_main); 537 linkmap_add(&obj_rtld); 538 539 /* Link the main program into the list of objects. */ 540 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 541 obj_count++; 542 obj_loads++; 543 544 /* Initialize a fake symbol for resolving undefined weak references. */ 545 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 546 sym_zero.st_shndx = SHN_UNDEF; 547 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 548 549 if (!libmap_disable) 550 libmap_disable = (bool)lm_init(libmap_override); 551 552 dbg("loading LD_PRELOAD libraries"); 553 if (load_preload_objects() == -1) 554 rtld_die(); 555 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 556 557 dbg("loading needed objects"); 558 if (load_needed_objects(obj_main, 0) == -1) 559 rtld_die(); 560 561 /* Make a list of all objects loaded at startup. */ 562 last_interposer = obj_main; 563 TAILQ_FOREACH(obj, &obj_list, next) { 564 if (obj->marker) 565 continue; 566 if (obj->z_interpose && obj != obj_main) { 567 objlist_put_after(&list_main, last_interposer, obj); 568 last_interposer = obj; 569 } else { 570 objlist_push_tail(&list_main, obj); 571 } 572 obj->refcount++; 573 } 574 575 dbg("checking for required versions"); 576 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 577 rtld_die(); 578 579 if (ld_tracing) { /* We're done */ 580 trace_loaded_objects(obj_main); 581 exit(0); 582 } 583 584 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 585 dump_relocations(obj_main); 586 exit (0); 587 } 588 589 /* 590 * Processing tls relocations requires having the tls offsets 591 * initialized. Prepare offsets before starting initial 592 * relocation processing. 593 */ 594 dbg("initializing initial thread local storage offsets"); 595 STAILQ_FOREACH(entry, &list_main, link) { 596 /* 597 * Allocate all the initial objects out of the static TLS 598 * block even if they didn't ask for it. 599 */ 600 allocate_tls_offset(entry->obj); 601 } 602 603 if (relocate_objects(obj_main, 604 ld_bind_now != NULL && *ld_bind_now != '\0', 605 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 606 rtld_die(); 607 608 dbg("doing copy relocations"); 609 if (do_copy_relocations(obj_main) == -1) 610 rtld_die(); 611 612 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 613 dump_relocations(obj_main); 614 exit (0); 615 } 616 617 /* 618 * Setup TLS for main thread. This must be done after the 619 * relocations are processed, since tls initialization section 620 * might be the subject for relocations. 621 */ 622 dbg("initializing initial thread local storage"); 623 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 624 625 dbg("initializing key program variables"); 626 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 627 set_program_var("environ", env); 628 set_program_var("__elf_aux_vector", aux); 629 630 /* Make a list of init functions to call. */ 631 objlist_init(&initlist); 632 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 633 preload_tail, &initlist); 634 635 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 636 637 map_stacks_exec(NULL); 638 ifunc_init(aux); 639 640 dbg("resolving ifuncs"); 641 if (resolve_objects_ifunc(obj_main, 642 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 643 NULL) == -1) 644 rtld_die(); 645 646 if (!obj_main->crt_no_init) { 647 /* 648 * Make sure we don't call the main program's init and fini 649 * functions for binaries linked with old crt1 which calls 650 * _init itself. 651 */ 652 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 653 obj_main->preinit_array = obj_main->init_array = 654 obj_main->fini_array = (Elf_Addr)NULL; 655 } 656 657 wlock_acquire(rtld_bind_lock, &lockstate); 658 if (obj_main->crt_no_init) 659 preinit_main(); 660 objlist_call_init(&initlist, &lockstate); 661 _r_debug_postinit(&obj_main->linkmap); 662 objlist_clear(&initlist); 663 dbg("loading filtees"); 664 TAILQ_FOREACH(obj, &obj_list, next) { 665 if (obj->marker) 666 continue; 667 if (ld_loadfltr || obj->z_loadfltr) 668 load_filtees(obj, 0, &lockstate); 669 } 670 lock_release(rtld_bind_lock, &lockstate); 671 672 dbg("transferring control to program entry point = %p", obj_main->entry); 673 674 /* Return the exit procedure and the program entry point. */ 675 *exit_proc = rtld_exit; 676 *objp = obj_main; 677 return (func_ptr_type) obj_main->entry; 678} 679 680void * 681rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 682{ 683 void *ptr; 684 Elf_Addr target; 685 686 ptr = (void *)make_function_pointer(def, obj); 687 target = call_ifunc_resolver(ptr); 688 return ((void *)target); 689} 690 691Elf_Addr 692_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 693{ 694 const Elf_Rel *rel; 695 const Elf_Sym *def; 696 const Obj_Entry *defobj; 697 Elf_Addr *where; 698 Elf_Addr target; 699 RtldLockState lockstate; 700 701 rlock_acquire(rtld_bind_lock, &lockstate); 702 if (sigsetjmp(lockstate.env, 0) != 0) 703 lock_upgrade(rtld_bind_lock, &lockstate); 704 if (obj->pltrel) 705 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 706 else 707 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 708 709 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 710 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 711 NULL, &lockstate); 712 if (def == NULL) 713 rtld_die(); 714 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 715 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 716 else 717 target = (Elf_Addr)(defobj->relocbase + def->st_value); 718 719 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 720 defobj->strtab + def->st_name, basename(obj->path), 721 (void *)target, basename(defobj->path)); 722 723 /* 724 * Write the new contents for the jmpslot. Note that depending on 725 * architecture, the value which we need to return back to the 726 * lazy binding trampoline may or may not be the target 727 * address. The value returned from reloc_jmpslot() is the value 728 * that the trampoline needs. 729 */ 730 target = reloc_jmpslot(where, target, defobj, obj, rel); 731 lock_release(rtld_bind_lock, &lockstate); 732 return target; 733} 734 735/* 736 * Error reporting function. Use it like printf. If formats the message 737 * into a buffer, and sets things up so that the next call to dlerror() 738 * will return the message. 739 */ 740void 741_rtld_error(const char *fmt, ...) 742{ 743 static char buf[512]; 744 va_list ap; 745 746 va_start(ap, fmt); 747 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 748 error_message = buf; 749 va_end(ap); 750} 751 752/* 753 * Return a dynamically-allocated copy of the current error message, if any. 754 */ 755static char * 756errmsg_save(void) 757{ 758 return error_message == NULL ? NULL : xstrdup(error_message); 759} 760 761/* 762 * Restore the current error message from a copy which was previously saved 763 * by errmsg_save(). The copy is freed. 764 */ 765static void 766errmsg_restore(char *saved_msg) 767{ 768 if (saved_msg == NULL) 769 error_message = NULL; 770 else { 771 _rtld_error("%s", saved_msg); 772 free(saved_msg); 773 } 774} 775 776static const char * 777basename(const char *name) 778{ 779 const char *p = strrchr(name, '/'); 780 return p != NULL ? p + 1 : name; 781} 782 783static struct utsname uts; 784 785static char * 786origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 787 const char *subst, bool may_free) 788{ 789 char *p, *p1, *res, *resp; 790 int subst_len, kw_len, subst_count, old_len, new_len; 791 792 kw_len = strlen(kw); 793 794 /* 795 * First, count the number of the keyword occurences, to 796 * preallocate the final string. 797 */ 798 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 799 p1 = strstr(p, kw); 800 if (p1 == NULL) 801 break; 802 } 803 804 /* 805 * If the keyword is not found, just return. 806 * 807 * Return non-substituted string if resolution failed. We 808 * cannot do anything more reasonable, the failure mode of the 809 * caller is unresolved library anyway. 810 */ 811 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 812 return (may_free ? real : xstrdup(real)); 813 if (obj != NULL) 814 subst = obj->origin_path; 815 816 /* 817 * There is indeed something to substitute. Calculate the 818 * length of the resulting string, and allocate it. 819 */ 820 subst_len = strlen(subst); 821 old_len = strlen(real); 822 new_len = old_len + (subst_len - kw_len) * subst_count; 823 res = xmalloc(new_len + 1); 824 825 /* 826 * Now, execute the substitution loop. 827 */ 828 for (p = real, resp = res, *resp = '\0';;) { 829 p1 = strstr(p, kw); 830 if (p1 != NULL) { 831 /* Copy the prefix before keyword. */ 832 memcpy(resp, p, p1 - p); 833 resp += p1 - p; 834 /* Keyword replacement. */ 835 memcpy(resp, subst, subst_len); 836 resp += subst_len; 837 *resp = '\0'; 838 p = p1 + kw_len; 839 } else 840 break; 841 } 842 843 /* Copy to the end of string and finish. */ 844 strcat(resp, p); 845 if (may_free) 846 free(real); 847 return (res); 848} 849 850static char * 851origin_subst(Obj_Entry *obj, char *real) 852{ 853 char *res1, *res2, *res3, *res4; 854 855 if (obj == NULL || !trust) 856 return (xstrdup(real)); 857 if (uts.sysname[0] == '\0') { 858 if (uname(&uts) != 0) { 859 _rtld_error("utsname failed: %d", errno); 860 return (NULL); 861 } 862 } 863 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 864 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 865 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 866 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 867 return (res4); 868} 869 870void 871rtld_die(void) 872{ 873 const char *msg = dlerror(); 874 875 if (msg == NULL) 876 msg = "Fatal error"; 877 rtld_fdputstr(STDERR_FILENO, msg); 878 rtld_fdputchar(STDERR_FILENO, '\n'); 879 _exit(1); 880} 881 882/* 883 * Process a shared object's DYNAMIC section, and save the important 884 * information in its Obj_Entry structure. 885 */ 886static void 887digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 888 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 889{ 890 const Elf_Dyn *dynp; 891 Needed_Entry **needed_tail = &obj->needed; 892 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 893 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 894 const Elf_Hashelt *hashtab; 895 const Elf32_Word *hashval; 896 Elf32_Word bkt, nmaskwords; 897 int bloom_size32; 898 int plttype = DT_REL; 899 900 *dyn_rpath = NULL; 901 *dyn_soname = NULL; 902 *dyn_runpath = NULL; 903 904 obj->bind_now = false; 905 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 906 switch (dynp->d_tag) { 907 908 case DT_REL: 909 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 910 break; 911 912 case DT_RELSZ: 913 obj->relsize = dynp->d_un.d_val; 914 break; 915 916 case DT_RELENT: 917 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 918 break; 919 920 case DT_JMPREL: 921 obj->pltrel = (const Elf_Rel *) 922 (obj->relocbase + dynp->d_un.d_ptr); 923 break; 924 925 case DT_PLTRELSZ: 926 obj->pltrelsize = dynp->d_un.d_val; 927 break; 928 929 case DT_RELA: 930 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 931 break; 932 933 case DT_RELASZ: 934 obj->relasize = dynp->d_un.d_val; 935 break; 936 937 case DT_RELAENT: 938 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 939 break; 940 941 case DT_PLTREL: 942 plttype = dynp->d_un.d_val; 943 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 944 break; 945 946 case DT_SYMTAB: 947 obj->symtab = (const Elf_Sym *) 948 (obj->relocbase + dynp->d_un.d_ptr); 949 break; 950 951 case DT_SYMENT: 952 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 953 break; 954 955 case DT_STRTAB: 956 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 957 break; 958 959 case DT_STRSZ: 960 obj->strsize = dynp->d_un.d_val; 961 break; 962 963 case DT_VERNEED: 964 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 965 dynp->d_un.d_val); 966 break; 967 968 case DT_VERNEEDNUM: 969 obj->verneednum = dynp->d_un.d_val; 970 break; 971 972 case DT_VERDEF: 973 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 974 dynp->d_un.d_val); 975 break; 976 977 case DT_VERDEFNUM: 978 obj->verdefnum = dynp->d_un.d_val; 979 break; 980 981 case DT_VERSYM: 982 obj->versyms = (const Elf_Versym *)(obj->relocbase + 983 dynp->d_un.d_val); 984 break; 985 986 case DT_HASH: 987 { 988 hashtab = (const Elf_Hashelt *)(obj->relocbase + 989 dynp->d_un.d_ptr); 990 obj->nbuckets = hashtab[0]; 991 obj->nchains = hashtab[1]; 992 obj->buckets = hashtab + 2; 993 obj->chains = obj->buckets + obj->nbuckets; 994 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 995 obj->buckets != NULL; 996 } 997 break; 998 999 case DT_GNU_HASH: 1000 { 1001 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1002 dynp->d_un.d_ptr); 1003 obj->nbuckets_gnu = hashtab[0]; 1004 obj->symndx_gnu = hashtab[1]; 1005 nmaskwords = hashtab[2]; 1006 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1007 obj->maskwords_bm_gnu = nmaskwords - 1; 1008 obj->shift2_gnu = hashtab[3]; 1009 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1010 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1011 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1012 obj->symndx_gnu; 1013 /* Number of bitmask words is required to be power of 2 */ 1014 obj->valid_hash_gnu = powerof2(nmaskwords) && 1015 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1016 } 1017 break; 1018 1019 case DT_NEEDED: 1020 if (!obj->rtld) { 1021 Needed_Entry *nep = NEW(Needed_Entry); 1022 nep->name = dynp->d_un.d_val; 1023 nep->obj = NULL; 1024 nep->next = NULL; 1025 1026 *needed_tail = nep; 1027 needed_tail = &nep->next; 1028 } 1029 break; 1030 1031 case DT_FILTER: 1032 if (!obj->rtld) { 1033 Needed_Entry *nep = NEW(Needed_Entry); 1034 nep->name = dynp->d_un.d_val; 1035 nep->obj = NULL; 1036 nep->next = NULL; 1037 1038 *needed_filtees_tail = nep; 1039 needed_filtees_tail = &nep->next; 1040 } 1041 break; 1042 1043 case DT_AUXILIARY: 1044 if (!obj->rtld) { 1045 Needed_Entry *nep = NEW(Needed_Entry); 1046 nep->name = dynp->d_un.d_val; 1047 nep->obj = NULL; 1048 nep->next = NULL; 1049 1050 *needed_aux_filtees_tail = nep; 1051 needed_aux_filtees_tail = &nep->next; 1052 } 1053 break; 1054 1055 case DT_PLTGOT: 1056 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1057 break; 1058 1059 case DT_TEXTREL: 1060 obj->textrel = true; 1061 break; 1062 1063 case DT_SYMBOLIC: 1064 obj->symbolic = true; 1065 break; 1066 1067 case DT_RPATH: 1068 /* 1069 * We have to wait until later to process this, because we 1070 * might not have gotten the address of the string table yet. 1071 */ 1072 *dyn_rpath = dynp; 1073 break; 1074 1075 case DT_SONAME: 1076 *dyn_soname = dynp; 1077 break; 1078 1079 case DT_RUNPATH: 1080 *dyn_runpath = dynp; 1081 break; 1082 1083 case DT_INIT: 1084 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1085 break; 1086 1087 case DT_PREINIT_ARRAY: 1088 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1089 break; 1090 1091 case DT_PREINIT_ARRAYSZ: 1092 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1093 break; 1094 1095 case DT_INIT_ARRAY: 1096 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1097 break; 1098 1099 case DT_INIT_ARRAYSZ: 1100 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1101 break; 1102 1103 case DT_FINI: 1104 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1105 break; 1106 1107 case DT_FINI_ARRAY: 1108 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1109 break; 1110 1111 case DT_FINI_ARRAYSZ: 1112 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1113 break; 1114 1115 /* 1116 * Don't process DT_DEBUG on MIPS as the dynamic section 1117 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1118 */ 1119 1120#ifndef __mips__ 1121 case DT_DEBUG: 1122 if (!early) 1123 dbg("Filling in DT_DEBUG entry"); 1124 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1125 break; 1126#endif 1127 1128 case DT_FLAGS: 1129 if (dynp->d_un.d_val & DF_ORIGIN) 1130 obj->z_origin = true; 1131 if (dynp->d_un.d_val & DF_SYMBOLIC) 1132 obj->symbolic = true; 1133 if (dynp->d_un.d_val & DF_TEXTREL) 1134 obj->textrel = true; 1135 if (dynp->d_un.d_val & DF_BIND_NOW) 1136 obj->bind_now = true; 1137 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1138 ;*/ 1139 break; 1140#ifdef __mips__ 1141 case DT_MIPS_LOCAL_GOTNO: 1142 obj->local_gotno = dynp->d_un.d_val; 1143 break; 1144 1145 case DT_MIPS_SYMTABNO: 1146 obj->symtabno = dynp->d_un.d_val; 1147 break; 1148 1149 case DT_MIPS_GOTSYM: 1150 obj->gotsym = dynp->d_un.d_val; 1151 break; 1152 1153 case DT_MIPS_RLD_MAP: 1154 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1155 break; 1156#endif 1157 1158 case DT_FLAGS_1: 1159 if (dynp->d_un.d_val & DF_1_NOOPEN) 1160 obj->z_noopen = true; 1161 if (dynp->d_un.d_val & DF_1_ORIGIN) 1162 obj->z_origin = true; 1163 if (dynp->d_un.d_val & DF_1_GLOBAL) 1164 obj->z_global = true; 1165 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1166 obj->bind_now = true; 1167 if (dynp->d_un.d_val & DF_1_NODELETE) 1168 obj->z_nodelete = true; 1169 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1170 obj->z_loadfltr = true; 1171 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1172 obj->z_interpose = true; 1173 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1174 obj->z_nodeflib = true; 1175 break; 1176 1177 default: 1178 if (!early) { 1179 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1180 (long)dynp->d_tag); 1181 } 1182 break; 1183 } 1184 } 1185 1186 obj->traced = false; 1187 1188 if (plttype == DT_RELA) { 1189 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1190 obj->pltrel = NULL; 1191 obj->pltrelasize = obj->pltrelsize; 1192 obj->pltrelsize = 0; 1193 } 1194 1195 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1196 if (obj->valid_hash_sysv) 1197 obj->dynsymcount = obj->nchains; 1198 else if (obj->valid_hash_gnu) { 1199 obj->dynsymcount = 0; 1200 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1201 if (obj->buckets_gnu[bkt] == 0) 1202 continue; 1203 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1204 do 1205 obj->dynsymcount++; 1206 while ((*hashval++ & 1u) == 0); 1207 } 1208 obj->dynsymcount += obj->symndx_gnu; 1209 } 1210} 1211 1212static bool 1213obj_resolve_origin(Obj_Entry *obj) 1214{ 1215 1216 if (obj->origin_path != NULL) 1217 return (true); 1218 obj->origin_path = xmalloc(PATH_MAX); 1219 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1220} 1221 1222static void 1223digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1224 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1225{ 1226 1227 if (obj->z_origin && !obj_resolve_origin(obj)) 1228 rtld_die(); 1229 1230 if (dyn_runpath != NULL) { 1231 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1232 obj->runpath = origin_subst(obj, obj->runpath); 1233 } else if (dyn_rpath != NULL) { 1234 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1235 obj->rpath = origin_subst(obj, obj->rpath); 1236 } 1237 if (dyn_soname != NULL) 1238 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1239} 1240 1241static void 1242digest_dynamic(Obj_Entry *obj, int early) 1243{ 1244 const Elf_Dyn *dyn_rpath; 1245 const Elf_Dyn *dyn_soname; 1246 const Elf_Dyn *dyn_runpath; 1247 1248 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1249 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1250} 1251 1252/* 1253 * Process a shared object's program header. This is used only for the 1254 * main program, when the kernel has already loaded the main program 1255 * into memory before calling the dynamic linker. It creates and 1256 * returns an Obj_Entry structure. 1257 */ 1258static Obj_Entry * 1259digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1260{ 1261 Obj_Entry *obj; 1262 const Elf_Phdr *phlimit = phdr + phnum; 1263 const Elf_Phdr *ph; 1264 Elf_Addr note_start, note_end; 1265 int nsegs = 0; 1266 1267 obj = obj_new(); 1268 for (ph = phdr; ph < phlimit; ph++) { 1269 if (ph->p_type != PT_PHDR) 1270 continue; 1271 1272 obj->phdr = phdr; 1273 obj->phsize = ph->p_memsz; 1274 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1275 break; 1276 } 1277 1278 obj->stack_flags = PF_X | PF_R | PF_W; 1279 1280 for (ph = phdr; ph < phlimit; ph++) { 1281 switch (ph->p_type) { 1282 1283 case PT_INTERP: 1284 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1285 break; 1286 1287 case PT_LOAD: 1288 if (nsegs == 0) { /* First load segment */ 1289 obj->vaddrbase = trunc_page(ph->p_vaddr); 1290 obj->mapbase = obj->vaddrbase + obj->relocbase; 1291 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1292 obj->vaddrbase; 1293 } else { /* Last load segment */ 1294 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1295 obj->vaddrbase; 1296 } 1297 nsegs++; 1298 break; 1299 1300 case PT_DYNAMIC: 1301 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1302 break; 1303 1304 case PT_TLS: 1305 obj->tlsindex = 1; 1306 obj->tlssize = ph->p_memsz; 1307 obj->tlsalign = ph->p_align; 1308 obj->tlsinitsize = ph->p_filesz; 1309 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1310 break; 1311 1312 case PT_GNU_STACK: 1313 obj->stack_flags = ph->p_flags; 1314 break; 1315 1316 case PT_GNU_RELRO: 1317 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1318 obj->relro_size = round_page(ph->p_memsz); 1319 break; 1320 1321 case PT_NOTE: 1322 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1323 note_end = note_start + ph->p_filesz; 1324 digest_notes(obj, note_start, note_end); 1325 break; 1326 } 1327 } 1328 if (nsegs < 1) { 1329 _rtld_error("%s: too few PT_LOAD segments", path); 1330 return NULL; 1331 } 1332 1333 obj->entry = entry; 1334 return obj; 1335} 1336 1337void 1338digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1339{ 1340 const Elf_Note *note; 1341 const char *note_name; 1342 uintptr_t p; 1343 1344 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1345 note = (const Elf_Note *)((const char *)(note + 1) + 1346 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1347 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1348 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1349 note->n_descsz != sizeof(int32_t)) 1350 continue; 1351 if (note->n_type != ABI_NOTETYPE && 1352 note->n_type != CRT_NOINIT_NOTETYPE) 1353 continue; 1354 note_name = (const char *)(note + 1); 1355 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1356 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1357 continue; 1358 switch (note->n_type) { 1359 case ABI_NOTETYPE: 1360 /* FreeBSD osrel note */ 1361 p = (uintptr_t)(note + 1); 1362 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1363 obj->osrel = *(const int32_t *)(p); 1364 dbg("note osrel %d", obj->osrel); 1365 break; 1366 case CRT_NOINIT_NOTETYPE: 1367 /* FreeBSD 'crt does not call init' note */ 1368 obj->crt_no_init = true; 1369 dbg("note crt_no_init"); 1370 break; 1371 } 1372 } 1373} 1374 1375static Obj_Entry * 1376dlcheck(void *handle) 1377{ 1378 Obj_Entry *obj; 1379 1380 TAILQ_FOREACH(obj, &obj_list, next) { 1381 if (obj == (Obj_Entry *) handle) 1382 break; 1383 } 1384 1385 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1386 _rtld_error("Invalid shared object handle %p", handle); 1387 return NULL; 1388 } 1389 return obj; 1390} 1391 1392/* 1393 * If the given object is already in the donelist, return true. Otherwise 1394 * add the object to the list and return false. 1395 */ 1396static bool 1397donelist_check(DoneList *dlp, const Obj_Entry *obj) 1398{ 1399 unsigned int i; 1400 1401 for (i = 0; i < dlp->num_used; i++) 1402 if (dlp->objs[i] == obj) 1403 return true; 1404 /* 1405 * Our donelist allocation should always be sufficient. But if 1406 * our threads locking isn't working properly, more shared objects 1407 * could have been loaded since we allocated the list. That should 1408 * never happen, but we'll handle it properly just in case it does. 1409 */ 1410 if (dlp->num_used < dlp->num_alloc) 1411 dlp->objs[dlp->num_used++] = obj; 1412 return false; 1413} 1414 1415/* 1416 * Hash function for symbol table lookup. Don't even think about changing 1417 * this. It is specified by the System V ABI. 1418 */ 1419unsigned long 1420elf_hash(const char *name) 1421{ 1422 const unsigned char *p = (const unsigned char *) name; 1423 unsigned long h = 0; 1424 unsigned long g; 1425 1426 while (*p != '\0') { 1427 h = (h << 4) + *p++; 1428 if ((g = h & 0xf0000000) != 0) 1429 h ^= g >> 24; 1430 h &= ~g; 1431 } 1432 return h; 1433} 1434 1435/* 1436 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1437 * unsigned in case it's implemented with a wider type. 1438 */ 1439static uint32_t 1440gnu_hash(const char *s) 1441{ 1442 uint32_t h; 1443 unsigned char c; 1444 1445 h = 5381; 1446 for (c = *s; c != '\0'; c = *++s) 1447 h = h * 33 + c; 1448 return (h & 0xffffffff); 1449} 1450 1451/* 1452 * Find the library with the given name, and return its full pathname. 1453 * The returned string is dynamically allocated. Generates an error 1454 * message and returns NULL if the library cannot be found. 1455 * 1456 * If the second argument is non-NULL, then it refers to an already- 1457 * loaded shared object, whose library search path will be searched. 1458 * 1459 * The search order is: 1460 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1461 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1462 * LD_LIBRARY_PATH 1463 * DT_RUNPATH in the referencing file 1464 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1465 * from list) 1466 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1467 * 1468 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1469 */ 1470static char * 1471find_library(const char *xname, const Obj_Entry *refobj) 1472{ 1473 char *pathname; 1474 char *name; 1475 bool nodeflib, objgiven; 1476 1477 objgiven = refobj != NULL; 1478 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1479 if (xname[0] != '/' && !trust) { 1480 _rtld_error("Absolute pathname required for shared object \"%s\"", 1481 xname); 1482 return NULL; 1483 } 1484 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1485 __DECONST(char *, xname))); 1486 } 1487 1488 if (libmap_disable || !objgiven || 1489 (name = lm_find(refobj->path, xname)) == NULL) 1490 name = (char *)xname; 1491 1492 dbg(" Searching for \"%s\"", name); 1493 1494 /* 1495 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1496 * back to pre-conforming behaviour if user requested so with 1497 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1498 * nodeflib. 1499 */ 1500 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1501 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1502 (refobj != NULL && 1503 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1504 (pathname = search_library_path(name, gethints(false))) != NULL || 1505 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1506 return (pathname); 1507 } else { 1508 nodeflib = objgiven ? refobj->z_nodeflib : false; 1509 if ((objgiven && 1510 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1511 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1512 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1513 (pathname = search_library_path(name, ld_library_path)) != NULL || 1514 (objgiven && 1515 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1516 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1517 (objgiven && !nodeflib && 1518 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1519 return (pathname); 1520 } 1521 1522 if (objgiven && refobj->path != NULL) { 1523 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1524 name, basename(refobj->path)); 1525 } else { 1526 _rtld_error("Shared object \"%s\" not found", name); 1527 } 1528 return NULL; 1529} 1530 1531/* 1532 * Given a symbol number in a referencing object, find the corresponding 1533 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1534 * no definition was found. Returns a pointer to the Obj_Entry of the 1535 * defining object via the reference parameter DEFOBJ_OUT. 1536 */ 1537const Elf_Sym * 1538find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1539 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1540 RtldLockState *lockstate) 1541{ 1542 const Elf_Sym *ref; 1543 const Elf_Sym *def; 1544 const Obj_Entry *defobj; 1545 SymLook req; 1546 const char *name; 1547 int res; 1548 1549 /* 1550 * If we have already found this symbol, get the information from 1551 * the cache. 1552 */ 1553 if (symnum >= refobj->dynsymcount) 1554 return NULL; /* Bad object */ 1555 if (cache != NULL && cache[symnum].sym != NULL) { 1556 *defobj_out = cache[symnum].obj; 1557 return cache[symnum].sym; 1558 } 1559 1560 ref = refobj->symtab + symnum; 1561 name = refobj->strtab + ref->st_name; 1562 def = NULL; 1563 defobj = NULL; 1564 1565 /* 1566 * We don't have to do a full scale lookup if the symbol is local. 1567 * We know it will bind to the instance in this load module; to 1568 * which we already have a pointer (ie ref). By not doing a lookup, 1569 * we not only improve performance, but it also avoids unresolvable 1570 * symbols when local symbols are not in the hash table. This has 1571 * been seen with the ia64 toolchain. 1572 */ 1573 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1574 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1575 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1576 symnum); 1577 } 1578 symlook_init(&req, name); 1579 req.flags = flags; 1580 req.ventry = fetch_ventry(refobj, symnum); 1581 req.lockstate = lockstate; 1582 res = symlook_default(&req, refobj); 1583 if (res == 0) { 1584 def = req.sym_out; 1585 defobj = req.defobj_out; 1586 } 1587 } else { 1588 def = ref; 1589 defobj = refobj; 1590 } 1591 1592 /* 1593 * If we found no definition and the reference is weak, treat the 1594 * symbol as having the value zero. 1595 */ 1596 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1597 def = &sym_zero; 1598 defobj = obj_main; 1599 } 1600 1601 if (def != NULL) { 1602 *defobj_out = defobj; 1603 /* Record the information in the cache to avoid subsequent lookups. */ 1604 if (cache != NULL) { 1605 cache[symnum].sym = def; 1606 cache[symnum].obj = defobj; 1607 } 1608 } else { 1609 if (refobj != &obj_rtld) 1610 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1611 } 1612 return def; 1613} 1614 1615/* 1616 * Return the search path from the ldconfig hints file, reading it if 1617 * necessary. If nostdlib is true, then the default search paths are 1618 * not added to result. 1619 * 1620 * Returns NULL if there are problems with the hints file, 1621 * or if the search path there is empty. 1622 */ 1623static const char * 1624gethints(bool nostdlib) 1625{ 1626 static char *hints, *filtered_path; 1627 static struct elfhints_hdr hdr; 1628 struct fill_search_info_args sargs, hargs; 1629 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1630 struct dl_serpath *SLPpath, *hintpath; 1631 char *p; 1632 struct stat hint_stat; 1633 unsigned int SLPndx, hintndx, fndx, fcount; 1634 int fd; 1635 size_t flen; 1636 uint32_t dl; 1637 bool skip; 1638 1639 /* First call, read the hints file */ 1640 if (hints == NULL) { 1641 /* Keep from trying again in case the hints file is bad. */ 1642 hints = ""; 1643 1644 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1645 return (NULL); 1646 1647 /* 1648 * Check of hdr.dirlistlen value against type limit 1649 * intends to pacify static analyzers. Further 1650 * paranoia leads to checks that dirlist is fully 1651 * contained in the file range. 1652 */ 1653 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1654 hdr.magic != ELFHINTS_MAGIC || 1655 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1656 fstat(fd, &hint_stat) == -1) { 1657cleanup1: 1658 close(fd); 1659 hdr.dirlistlen = 0; 1660 return (NULL); 1661 } 1662 dl = hdr.strtab; 1663 if (dl + hdr.dirlist < dl) 1664 goto cleanup1; 1665 dl += hdr.dirlist; 1666 if (dl + hdr.dirlistlen < dl) 1667 goto cleanup1; 1668 dl += hdr.dirlistlen; 1669 if (dl > hint_stat.st_size) 1670 goto cleanup1; 1671 p = xmalloc(hdr.dirlistlen + 1); 1672 1673 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1674 read(fd, p, hdr.dirlistlen + 1) != 1675 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1676 free(p); 1677 goto cleanup1; 1678 } 1679 hints = p; 1680 close(fd); 1681 } 1682 1683 /* 1684 * If caller agreed to receive list which includes the default 1685 * paths, we are done. Otherwise, if we still did not 1686 * calculated filtered result, do it now. 1687 */ 1688 if (!nostdlib) 1689 return (hints[0] != '\0' ? hints : NULL); 1690 if (filtered_path != NULL) 1691 goto filt_ret; 1692 1693 /* 1694 * Obtain the list of all configured search paths, and the 1695 * list of the default paths. 1696 * 1697 * First estimate the size of the results. 1698 */ 1699 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1700 smeta.dls_cnt = 0; 1701 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1702 hmeta.dls_cnt = 0; 1703 1704 sargs.request = RTLD_DI_SERINFOSIZE; 1705 sargs.serinfo = &smeta; 1706 hargs.request = RTLD_DI_SERINFOSIZE; 1707 hargs.serinfo = &hmeta; 1708 1709 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1710 path_enumerate(hints, fill_search_info, &hargs); 1711 1712 SLPinfo = xmalloc(smeta.dls_size); 1713 hintinfo = xmalloc(hmeta.dls_size); 1714 1715 /* 1716 * Next fetch both sets of paths. 1717 */ 1718 sargs.request = RTLD_DI_SERINFO; 1719 sargs.serinfo = SLPinfo; 1720 sargs.serpath = &SLPinfo->dls_serpath[0]; 1721 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1722 1723 hargs.request = RTLD_DI_SERINFO; 1724 hargs.serinfo = hintinfo; 1725 hargs.serpath = &hintinfo->dls_serpath[0]; 1726 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1727 1728 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1729 path_enumerate(hints, fill_search_info, &hargs); 1730 1731 /* 1732 * Now calculate the difference between two sets, by excluding 1733 * standard paths from the full set. 1734 */ 1735 fndx = 0; 1736 fcount = 0; 1737 filtered_path = xmalloc(hdr.dirlistlen + 1); 1738 hintpath = &hintinfo->dls_serpath[0]; 1739 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1740 skip = false; 1741 SLPpath = &SLPinfo->dls_serpath[0]; 1742 /* 1743 * Check each standard path against current. 1744 */ 1745 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1746 /* matched, skip the path */ 1747 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1748 skip = true; 1749 break; 1750 } 1751 } 1752 if (skip) 1753 continue; 1754 /* 1755 * Not matched against any standard path, add the path 1756 * to result. Separate consequtive paths with ':'. 1757 */ 1758 if (fcount > 0) { 1759 filtered_path[fndx] = ':'; 1760 fndx++; 1761 } 1762 fcount++; 1763 flen = strlen(hintpath->dls_name); 1764 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1765 fndx += flen; 1766 } 1767 filtered_path[fndx] = '\0'; 1768 1769 free(SLPinfo); 1770 free(hintinfo); 1771 1772filt_ret: 1773 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1774} 1775 1776static void 1777init_dag(Obj_Entry *root) 1778{ 1779 const Needed_Entry *needed; 1780 const Objlist_Entry *elm; 1781 DoneList donelist; 1782 1783 if (root->dag_inited) 1784 return; 1785 donelist_init(&donelist); 1786 1787 /* Root object belongs to own DAG. */ 1788 objlist_push_tail(&root->dldags, root); 1789 objlist_push_tail(&root->dagmembers, root); 1790 donelist_check(&donelist, root); 1791 1792 /* 1793 * Add dependencies of root object to DAG in breadth order 1794 * by exploiting the fact that each new object get added 1795 * to the tail of the dagmembers list. 1796 */ 1797 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1798 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1799 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1800 continue; 1801 objlist_push_tail(&needed->obj->dldags, root); 1802 objlist_push_tail(&root->dagmembers, needed->obj); 1803 } 1804 } 1805 root->dag_inited = true; 1806} 1807 1808Obj_Entry * 1809globallist_curr(const Obj_Entry *obj) 1810{ 1811 1812 for (;;) { 1813 if (obj == NULL) 1814 return (NULL); 1815 if (!obj->marker) 1816 return (__DECONST(Obj_Entry *, obj)); 1817 obj = TAILQ_PREV(obj, obj_entry_q, next); 1818 } 1819} 1820 1821Obj_Entry * 1822globallist_next(const Obj_Entry *obj) 1823{ 1824 1825 for (;;) { 1826 obj = TAILQ_NEXT(obj, next); 1827 if (obj == NULL) 1828 return (NULL); 1829 if (!obj->marker) 1830 return (__DECONST(Obj_Entry *, obj)); 1831 } 1832} 1833 1834static void 1835process_z(Obj_Entry *root) 1836{ 1837 const Objlist_Entry *elm; 1838 Obj_Entry *obj; 1839 1840 /* 1841 * Walk over object DAG and process every dependent object 1842 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1843 * to grow their own DAG. 1844 * 1845 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1846 * symlook_global() to work. 1847 * 1848 * For DF_1_NODELETE, the DAG should have its reference upped. 1849 */ 1850 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1851 obj = elm->obj; 1852 if (obj == NULL) 1853 continue; 1854 if (obj->z_nodelete && !obj->ref_nodel) { 1855 dbg("obj %s -z nodelete", obj->path); 1856 init_dag(obj); 1857 ref_dag(obj); 1858 obj->ref_nodel = true; 1859 } 1860 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1861 dbg("obj %s -z global", obj->path); 1862 objlist_push_tail(&list_global, obj); 1863 init_dag(obj); 1864 } 1865 } 1866} 1867/* 1868 * Initialize the dynamic linker. The argument is the address at which 1869 * the dynamic linker has been mapped into memory. The primary task of 1870 * this function is to relocate the dynamic linker. 1871 */ 1872static void 1873init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1874{ 1875 Obj_Entry objtmp; /* Temporary rtld object */ 1876 const Elf_Ehdr *ehdr; 1877 const Elf_Dyn *dyn_rpath; 1878 const Elf_Dyn *dyn_soname; 1879 const Elf_Dyn *dyn_runpath; 1880 1881#ifdef RTLD_INIT_PAGESIZES_EARLY 1882 /* The page size is required by the dynamic memory allocator. */ 1883 init_pagesizes(aux_info); 1884#endif 1885 1886 /* 1887 * Conjure up an Obj_Entry structure for the dynamic linker. 1888 * 1889 * The "path" member can't be initialized yet because string constants 1890 * cannot yet be accessed. Below we will set it correctly. 1891 */ 1892 memset(&objtmp, 0, sizeof(objtmp)); 1893 objtmp.path = NULL; 1894 objtmp.rtld = true; 1895 objtmp.mapbase = mapbase; 1896#ifdef PIC 1897 objtmp.relocbase = mapbase; 1898#endif 1899 if (RTLD_IS_DYNAMIC()) { 1900 objtmp.dynamic = rtld_dynamic(&objtmp); 1901 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1902 assert(objtmp.needed == NULL); 1903#if !defined(__mips__) 1904 /* MIPS has a bogus DT_TEXTREL. */ 1905 assert(!objtmp.textrel); 1906#endif 1907 1908 /* 1909 * Temporarily put the dynamic linker entry into the object list, so 1910 * that symbols can be found. 1911 */ 1912 1913 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1914 } 1915 ehdr = (Elf_Ehdr *)mapbase; 1916 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1917 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1918 1919 /* Initialize the object list. */ 1920 TAILQ_INIT(&obj_list); 1921 1922 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1923 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1924 1925#ifndef RTLD_INIT_PAGESIZES_EARLY 1926 /* The page size is required by the dynamic memory allocator. */ 1927 init_pagesizes(aux_info); 1928#endif 1929 1930 if (aux_info[AT_OSRELDATE] != NULL) 1931 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1932 1933 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1934 1935 /* Replace the path with a dynamically allocated copy. */ 1936 obj_rtld.path = xstrdup(PATH_RTLD); 1937 1938 r_debug.r_brk = r_debug_state; 1939 r_debug.r_state = RT_CONSISTENT; 1940} 1941 1942/* 1943 * Retrieve the array of supported page sizes. The kernel provides the page 1944 * sizes in increasing order. 1945 */ 1946static void 1947init_pagesizes(Elf_Auxinfo **aux_info) 1948{ 1949 static size_t psa[MAXPAGESIZES]; 1950 int mib[2]; 1951 size_t len, size; 1952 1953 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1954 NULL) { 1955 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1956 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1957 } else { 1958 len = 2; 1959 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1960 size = sizeof(psa); 1961 else { 1962 /* As a fallback, retrieve the base page size. */ 1963 size = sizeof(psa[0]); 1964 if (aux_info[AT_PAGESZ] != NULL) { 1965 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1966 goto psa_filled; 1967 } else { 1968 mib[0] = CTL_HW; 1969 mib[1] = HW_PAGESIZE; 1970 len = 2; 1971 } 1972 } 1973 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1974 _rtld_error("sysctl for hw.pagesize(s) failed"); 1975 rtld_die(); 1976 } 1977psa_filled: 1978 pagesizes = psa; 1979 } 1980 npagesizes = size / sizeof(pagesizes[0]); 1981 /* Discard any invalid entries at the end of the array. */ 1982 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1983 npagesizes--; 1984} 1985 1986/* 1987 * Add the init functions from a needed object list (and its recursive 1988 * needed objects) to "list". This is not used directly; it is a helper 1989 * function for initlist_add_objects(). The write lock must be held 1990 * when this function is called. 1991 */ 1992static void 1993initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1994{ 1995 /* Recursively process the successor needed objects. */ 1996 if (needed->next != NULL) 1997 initlist_add_neededs(needed->next, list); 1998 1999 /* Process the current needed object. */ 2000 if (needed->obj != NULL) 2001 initlist_add_objects(needed->obj, needed->obj, list); 2002} 2003 2004/* 2005 * Scan all of the DAGs rooted in the range of objects from "obj" to 2006 * "tail" and add their init functions to "list". This recurses over 2007 * the DAGs and ensure the proper init ordering such that each object's 2008 * needed libraries are initialized before the object itself. At the 2009 * same time, this function adds the objects to the global finalization 2010 * list "list_fini" in the opposite order. The write lock must be 2011 * held when this function is called. 2012 */ 2013static void 2014initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2015{ 2016 Obj_Entry *nobj; 2017 2018 if (obj->init_scanned || obj->init_done) 2019 return; 2020 obj->init_scanned = true; 2021 2022 /* Recursively process the successor objects. */ 2023 nobj = globallist_next(obj); 2024 if (nobj != NULL && obj != tail) 2025 initlist_add_objects(nobj, tail, list); 2026 2027 /* Recursively process the needed objects. */ 2028 if (obj->needed != NULL) 2029 initlist_add_neededs(obj->needed, list); 2030 if (obj->needed_filtees != NULL) 2031 initlist_add_neededs(obj->needed_filtees, list); 2032 if (obj->needed_aux_filtees != NULL) 2033 initlist_add_neededs(obj->needed_aux_filtees, list); 2034 2035 /* Add the object to the init list. */ 2036 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2037 obj->init_array != (Elf_Addr)NULL) 2038 objlist_push_tail(list, obj); 2039 2040 /* Add the object to the global fini list in the reverse order. */ 2041 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2042 && !obj->on_fini_list) { 2043 objlist_push_head(&list_fini, obj); 2044 obj->on_fini_list = true; 2045 } 2046} 2047 2048#ifndef FPTR_TARGET 2049#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2050#endif 2051 2052static void 2053free_needed_filtees(Needed_Entry *n) 2054{ 2055 Needed_Entry *needed, *needed1; 2056 2057 for (needed = n; needed != NULL; needed = needed->next) { 2058 if (needed->obj != NULL) { 2059 dlclose(needed->obj); 2060 needed->obj = NULL; 2061 } 2062 } 2063 for (needed = n; needed != NULL; needed = needed1) { 2064 needed1 = needed->next; 2065 free(needed); 2066 } 2067} 2068 2069static void 2070unload_filtees(Obj_Entry *obj) 2071{ 2072 2073 free_needed_filtees(obj->needed_filtees); 2074 obj->needed_filtees = NULL; 2075 free_needed_filtees(obj->needed_aux_filtees); 2076 obj->needed_aux_filtees = NULL; 2077 obj->filtees_loaded = false; 2078} 2079 2080static void 2081load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2082 RtldLockState *lockstate) 2083{ 2084 2085 for (; needed != NULL; needed = needed->next) { 2086 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2087 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2088 RTLD_LOCAL, lockstate); 2089 } 2090} 2091 2092static void 2093load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2094{ 2095 2096 lock_restart_for_upgrade(lockstate); 2097 if (!obj->filtees_loaded) { 2098 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2099 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2100 obj->filtees_loaded = true; 2101 } 2102} 2103 2104static int 2105process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2106{ 2107 Obj_Entry *obj1; 2108 2109 for (; needed != NULL; needed = needed->next) { 2110 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2111 flags & ~RTLD_LO_NOLOAD); 2112 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2113 return (-1); 2114 } 2115 return (0); 2116} 2117 2118/* 2119 * Given a shared object, traverse its list of needed objects, and load 2120 * each of them. Returns 0 on success. Generates an error message and 2121 * returns -1 on failure. 2122 */ 2123static int 2124load_needed_objects(Obj_Entry *first, int flags) 2125{ 2126 Obj_Entry *obj; 2127 2128 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2129 if (obj->marker) 2130 continue; 2131 if (process_needed(obj, obj->needed, flags) == -1) 2132 return (-1); 2133 } 2134 return (0); 2135} 2136 2137static int 2138load_preload_objects(void) 2139{ 2140 char *p = ld_preload; 2141 Obj_Entry *obj; 2142 static const char delim[] = " \t:;"; 2143 2144 if (p == NULL) 2145 return 0; 2146 2147 p += strspn(p, delim); 2148 while (*p != '\0') { 2149 size_t len = strcspn(p, delim); 2150 char savech; 2151 2152 savech = p[len]; 2153 p[len] = '\0'; 2154 obj = load_object(p, -1, NULL, 0); 2155 if (obj == NULL) 2156 return -1; /* XXX - cleanup */ 2157 obj->z_interpose = true; 2158 p[len] = savech; 2159 p += len; 2160 p += strspn(p, delim); 2161 } 2162 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2163 return 0; 2164} 2165 2166static const char * 2167printable_path(const char *path) 2168{ 2169 2170 return (path == NULL ? "<unknown>" : path); 2171} 2172 2173/* 2174 * Load a shared object into memory, if it is not already loaded. The 2175 * object may be specified by name or by user-supplied file descriptor 2176 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2177 * duplicate is. 2178 * 2179 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2180 * on failure. 2181 */ 2182static Obj_Entry * 2183load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2184{ 2185 Obj_Entry *obj; 2186 int fd; 2187 struct stat sb; 2188 char *path; 2189 2190 if (name != NULL) { 2191 TAILQ_FOREACH(obj, &obj_list, next) { 2192 if (obj->marker) 2193 continue; 2194 if (object_match_name(obj, name)) 2195 return (obj); 2196 } 2197 2198 path = find_library(name, refobj); 2199 if (path == NULL) 2200 return (NULL); 2201 } else 2202 path = NULL; 2203 2204 /* 2205 * If we didn't find a match by pathname, or the name is not 2206 * supplied, open the file and check again by device and inode. 2207 * This avoids false mismatches caused by multiple links or ".." 2208 * in pathnames. 2209 * 2210 * To avoid a race, we open the file and use fstat() rather than 2211 * using stat(). 2212 */ 2213 fd = -1; 2214 if (fd_u == -1) { 2215 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2216 _rtld_error("Cannot open \"%s\"", path); 2217 free(path); 2218 return (NULL); 2219 } 2220 } else { 2221 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2222 if (fd == -1) { 2223 _rtld_error("Cannot dup fd"); 2224 free(path); 2225 return (NULL); 2226 } 2227 } 2228 if (fstat(fd, &sb) == -1) { 2229 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2230 close(fd); 2231 free(path); 2232 return NULL; 2233 } 2234 TAILQ_FOREACH(obj, &obj_list, next) { 2235 if (obj->marker) 2236 continue; 2237 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2238 break; 2239 } 2240 if (obj != NULL && name != NULL) { 2241 object_add_name(obj, name); 2242 free(path); 2243 close(fd); 2244 return obj; 2245 } 2246 if (flags & RTLD_LO_NOLOAD) { 2247 free(path); 2248 close(fd); 2249 return (NULL); 2250 } 2251 2252 /* First use of this object, so we must map it in */ 2253 obj = do_load_object(fd, name, path, &sb, flags); 2254 if (obj == NULL) 2255 free(path); 2256 close(fd); 2257 2258 return obj; 2259} 2260 2261static Obj_Entry * 2262do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2263 int flags) 2264{ 2265 Obj_Entry *obj; 2266 struct statfs fs; 2267 2268 /* 2269 * but first, make sure that environment variables haven't been 2270 * used to circumvent the noexec flag on a filesystem. 2271 */ 2272 if (dangerous_ld_env) { 2273 if (fstatfs(fd, &fs) != 0) { 2274 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2275 return NULL; 2276 } 2277 if (fs.f_flags & MNT_NOEXEC) { 2278 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2279 return NULL; 2280 } 2281 } 2282 dbg("loading \"%s\"", printable_path(path)); 2283 obj = map_object(fd, printable_path(path), sbp); 2284 if (obj == NULL) 2285 return NULL; 2286 2287 /* 2288 * If DT_SONAME is present in the object, digest_dynamic2 already 2289 * added it to the object names. 2290 */ 2291 if (name != NULL) 2292 object_add_name(obj, name); 2293 obj->path = path; 2294 digest_dynamic(obj, 0); 2295 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2296 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2297 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2298 RTLD_LO_DLOPEN) { 2299 dbg("refusing to load non-loadable \"%s\"", obj->path); 2300 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2301 munmap(obj->mapbase, obj->mapsize); 2302 obj_free(obj); 2303 return (NULL); 2304 } 2305 2306 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2307 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2308 obj_count++; 2309 obj_loads++; 2310 linkmap_add(obj); /* for GDB & dlinfo() */ 2311 max_stack_flags |= obj->stack_flags; 2312 2313 dbg(" %p .. %p: %s", obj->mapbase, 2314 obj->mapbase + obj->mapsize - 1, obj->path); 2315 if (obj->textrel) 2316 dbg(" WARNING: %s has impure text", obj->path); 2317 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2318 obj->path); 2319 2320 return obj; 2321} 2322 2323static Obj_Entry * 2324obj_from_addr(const void *addr) 2325{ 2326 Obj_Entry *obj; 2327 2328 TAILQ_FOREACH(obj, &obj_list, next) { 2329 if (obj->marker) 2330 continue; 2331 if (addr < (void *) obj->mapbase) 2332 continue; 2333 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2334 return obj; 2335 } 2336 return NULL; 2337} 2338 2339static void 2340preinit_main(void) 2341{ 2342 Elf_Addr *preinit_addr; 2343 int index; 2344 2345 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2346 if (preinit_addr == NULL) 2347 return; 2348 2349 for (index = 0; index < obj_main->preinit_array_num; index++) { 2350 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2351 dbg("calling preinit function for %s at %p", obj_main->path, 2352 (void *)preinit_addr[index]); 2353 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2354 0, 0, obj_main->path); 2355 call_init_pointer(obj_main, preinit_addr[index]); 2356 } 2357 } 2358} 2359 2360/* 2361 * Call the finalization functions for each of the objects in "list" 2362 * belonging to the DAG of "root" and referenced once. If NULL "root" 2363 * is specified, every finalization function will be called regardless 2364 * of the reference count and the list elements won't be freed. All of 2365 * the objects are expected to have non-NULL fini functions. 2366 */ 2367static void 2368objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2369{ 2370 Objlist_Entry *elm; 2371 char *saved_msg; 2372 Elf_Addr *fini_addr; 2373 int index; 2374 2375 assert(root == NULL || root->refcount == 1); 2376 2377 /* 2378 * Preserve the current error message since a fini function might 2379 * call into the dynamic linker and overwrite it. 2380 */ 2381 saved_msg = errmsg_save(); 2382 do { 2383 STAILQ_FOREACH(elm, list, link) { 2384 if (root != NULL && (elm->obj->refcount != 1 || 2385 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2386 continue; 2387 /* Remove object from fini list to prevent recursive invocation. */ 2388 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2389 /* 2390 * XXX: If a dlopen() call references an object while the 2391 * fini function is in progress, we might end up trying to 2392 * unload the referenced object in dlclose() or the object 2393 * won't be unloaded although its fini function has been 2394 * called. 2395 */ 2396 lock_release(rtld_bind_lock, lockstate); 2397 2398 /* 2399 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2400 * When this happens, DT_FINI_ARRAY is processed first. 2401 */ 2402 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2403 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2404 for (index = elm->obj->fini_array_num - 1; index >= 0; 2405 index--) { 2406 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2407 dbg("calling fini function for %s at %p", 2408 elm->obj->path, (void *)fini_addr[index]); 2409 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2410 (void *)fini_addr[index], 0, 0, elm->obj->path); 2411 call_initfini_pointer(elm->obj, fini_addr[index]); 2412 } 2413 } 2414 } 2415 if (elm->obj->fini != (Elf_Addr)NULL) { 2416 dbg("calling fini function for %s at %p", elm->obj->path, 2417 (void *)elm->obj->fini); 2418 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2419 0, 0, elm->obj->path); 2420 call_initfini_pointer(elm->obj, elm->obj->fini); 2421 } 2422 wlock_acquire(rtld_bind_lock, lockstate); 2423 /* No need to free anything if process is going down. */ 2424 if (root != NULL) 2425 free(elm); 2426 /* 2427 * We must restart the list traversal after every fini call 2428 * because a dlclose() call from the fini function or from 2429 * another thread might have modified the reference counts. 2430 */ 2431 break; 2432 } 2433 } while (elm != NULL); 2434 errmsg_restore(saved_msg); 2435} 2436 2437/* 2438 * Call the initialization functions for each of the objects in 2439 * "list". All of the objects are expected to have non-NULL init 2440 * functions. 2441 */ 2442static void 2443objlist_call_init(Objlist *list, RtldLockState *lockstate) 2444{ 2445 Objlist_Entry *elm; 2446 Obj_Entry *obj; 2447 char *saved_msg; 2448 Elf_Addr *init_addr; 2449 int index; 2450 2451 /* 2452 * Clean init_scanned flag so that objects can be rechecked and 2453 * possibly initialized earlier if any of vectors called below 2454 * cause the change by using dlopen. 2455 */ 2456 TAILQ_FOREACH(obj, &obj_list, next) { 2457 if (obj->marker) 2458 continue; 2459 obj->init_scanned = false; 2460 } 2461 2462 /* 2463 * Preserve the current error message since an init function might 2464 * call into the dynamic linker and overwrite it. 2465 */ 2466 saved_msg = errmsg_save(); 2467 STAILQ_FOREACH(elm, list, link) { 2468 if (elm->obj->init_done) /* Initialized early. */ 2469 continue; 2470 /* 2471 * Race: other thread might try to use this object before current 2472 * one completes the initialization. Not much can be done here 2473 * without better locking. 2474 */ 2475 elm->obj->init_done = true; 2476 lock_release(rtld_bind_lock, lockstate); 2477 2478 /* 2479 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2480 * When this happens, DT_INIT is processed first. 2481 */ 2482 if (elm->obj->init != (Elf_Addr)NULL) { 2483 dbg("calling init function for %s at %p", elm->obj->path, 2484 (void *)elm->obj->init); 2485 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2486 0, 0, elm->obj->path); 2487 call_initfini_pointer(elm->obj, elm->obj->init); 2488 } 2489 init_addr = (Elf_Addr *)elm->obj->init_array; 2490 if (init_addr != NULL) { 2491 for (index = 0; index < elm->obj->init_array_num; index++) { 2492 if (init_addr[index] != 0 && init_addr[index] != 1) { 2493 dbg("calling init function for %s at %p", elm->obj->path, 2494 (void *)init_addr[index]); 2495 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2496 (void *)init_addr[index], 0, 0, elm->obj->path); 2497 call_init_pointer(elm->obj, init_addr[index]); 2498 } 2499 } 2500 } 2501 wlock_acquire(rtld_bind_lock, lockstate); 2502 } 2503 errmsg_restore(saved_msg); 2504} 2505 2506static void 2507objlist_clear(Objlist *list) 2508{ 2509 Objlist_Entry *elm; 2510 2511 while (!STAILQ_EMPTY(list)) { 2512 elm = STAILQ_FIRST(list); 2513 STAILQ_REMOVE_HEAD(list, link); 2514 free(elm); 2515 } 2516} 2517 2518static Objlist_Entry * 2519objlist_find(Objlist *list, const Obj_Entry *obj) 2520{ 2521 Objlist_Entry *elm; 2522 2523 STAILQ_FOREACH(elm, list, link) 2524 if (elm->obj == obj) 2525 return elm; 2526 return NULL; 2527} 2528 2529static void 2530objlist_init(Objlist *list) 2531{ 2532 STAILQ_INIT(list); 2533} 2534 2535static void 2536objlist_push_head(Objlist *list, Obj_Entry *obj) 2537{ 2538 Objlist_Entry *elm; 2539 2540 elm = NEW(Objlist_Entry); 2541 elm->obj = obj; 2542 STAILQ_INSERT_HEAD(list, elm, link); 2543} 2544 2545static void 2546objlist_push_tail(Objlist *list, Obj_Entry *obj) 2547{ 2548 Objlist_Entry *elm; 2549 2550 elm = NEW(Objlist_Entry); 2551 elm->obj = obj; 2552 STAILQ_INSERT_TAIL(list, elm, link); 2553} 2554 2555static void 2556objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2557{ 2558 Objlist_Entry *elm, *listelm; 2559 2560 STAILQ_FOREACH(listelm, list, link) { 2561 if (listelm->obj == listobj) 2562 break; 2563 } 2564 elm = NEW(Objlist_Entry); 2565 elm->obj = obj; 2566 if (listelm != NULL) 2567 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2568 else 2569 STAILQ_INSERT_TAIL(list, elm, link); 2570} 2571 2572static void 2573objlist_remove(Objlist *list, Obj_Entry *obj) 2574{ 2575 Objlist_Entry *elm; 2576 2577 if ((elm = objlist_find(list, obj)) != NULL) { 2578 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2579 free(elm); 2580 } 2581} 2582 2583/* 2584 * Relocate dag rooted in the specified object. 2585 * Returns 0 on success, or -1 on failure. 2586 */ 2587 2588static int 2589relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2590 int flags, RtldLockState *lockstate) 2591{ 2592 Objlist_Entry *elm; 2593 int error; 2594 2595 error = 0; 2596 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2597 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2598 lockstate); 2599 if (error == -1) 2600 break; 2601 } 2602 return (error); 2603} 2604 2605/* 2606 * Prepare for, or clean after, relocating an object marked with 2607 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2608 * segments are remapped read-write. After relocations are done, the 2609 * segment's permissions are returned back to the modes specified in 2610 * the phdrs. If any relocation happened, or always for wired 2611 * program, COW is triggered. 2612 */ 2613static int 2614reloc_textrel_prot(Obj_Entry *obj, bool before) 2615{ 2616 const Elf_Phdr *ph; 2617 void *base; 2618 size_t l, sz; 2619 int prot; 2620 2621 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2622 l--, ph++) { 2623 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2624 continue; 2625 base = obj->relocbase + trunc_page(ph->p_vaddr); 2626 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2627 trunc_page(ph->p_vaddr); 2628 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2629 if (mprotect(base, sz, prot) == -1) { 2630 _rtld_error("%s: Cannot write-%sable text segment: %s", 2631 obj->path, before ? "en" : "dis", 2632 rtld_strerror(errno)); 2633 return (-1); 2634 } 2635 } 2636 return (0); 2637} 2638 2639/* 2640 * Relocate single object. 2641 * Returns 0 on success, or -1 on failure. 2642 */ 2643static int 2644relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2645 int flags, RtldLockState *lockstate) 2646{ 2647 2648 if (obj->relocated) 2649 return (0); 2650 obj->relocated = true; 2651 if (obj != rtldobj) 2652 dbg("relocating \"%s\"", obj->path); 2653 2654 if (obj->symtab == NULL || obj->strtab == NULL || 2655 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2656 _rtld_error("%s: Shared object has no run-time symbol table", 2657 obj->path); 2658 return (-1); 2659 } 2660 2661 /* There are relocations to the write-protected text segment. */ 2662 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2663 return (-1); 2664 2665 /* Process the non-PLT non-IFUNC relocations. */ 2666 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2667 return (-1); 2668 2669 /* Re-protected the text segment. */ 2670 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2671 return (-1); 2672 2673 /* Set the special PLT or GOT entries. */ 2674 init_pltgot(obj); 2675 2676 /* Process the PLT relocations. */ 2677 if (reloc_plt(obj) == -1) 2678 return (-1); 2679 /* Relocate the jump slots if we are doing immediate binding. */ 2680 if (obj->bind_now || bind_now) 2681 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2682 return (-1); 2683 2684 /* 2685 * Process the non-PLT IFUNC relocations. The relocations are 2686 * processed in two phases, because IFUNC resolvers may 2687 * reference other symbols, which must be readily processed 2688 * before resolvers are called. 2689 */ 2690 if (obj->non_plt_gnu_ifunc && 2691 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2692 return (-1); 2693 2694 if (obj->relro_size > 0) { 2695 if (mprotect(obj->relro_page, obj->relro_size, 2696 PROT_READ) == -1) { 2697 _rtld_error("%s: Cannot enforce relro protection: %s", 2698 obj->path, rtld_strerror(errno)); 2699 return (-1); 2700 } 2701 } 2702 2703 /* 2704 * Set up the magic number and version in the Obj_Entry. These 2705 * were checked in the crt1.o from the original ElfKit, so we 2706 * set them for backward compatibility. 2707 */ 2708 obj->magic = RTLD_MAGIC; 2709 obj->version = RTLD_VERSION; 2710 2711 return (0); 2712} 2713 2714/* 2715 * Relocate newly-loaded shared objects. The argument is a pointer to 2716 * the Obj_Entry for the first such object. All objects from the first 2717 * to the end of the list of objects are relocated. Returns 0 on success, 2718 * or -1 on failure. 2719 */ 2720static int 2721relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2722 int flags, RtldLockState *lockstate) 2723{ 2724 Obj_Entry *obj; 2725 int error; 2726 2727 for (error = 0, obj = first; obj != NULL; 2728 obj = TAILQ_NEXT(obj, next)) { 2729 if (obj->marker) 2730 continue; 2731 error = relocate_object(obj, bind_now, rtldobj, flags, 2732 lockstate); 2733 if (error == -1) 2734 break; 2735 } 2736 return (error); 2737} 2738 2739/* 2740 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2741 * referencing STT_GNU_IFUNC symbols is postponed till the other 2742 * relocations are done. The indirect functions specified as 2743 * ifunc are allowed to call other symbols, so we need to have 2744 * objects relocated before asking for resolution from indirects. 2745 * 2746 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2747 * instead of the usual lazy handling of PLT slots. It is 2748 * consistent with how GNU does it. 2749 */ 2750static int 2751resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2752 RtldLockState *lockstate) 2753{ 2754 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2755 return (-1); 2756 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2757 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2758 return (-1); 2759 return (0); 2760} 2761 2762static int 2763resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2764 RtldLockState *lockstate) 2765{ 2766 Obj_Entry *obj; 2767 2768 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2769 if (obj->marker) 2770 continue; 2771 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2772 return (-1); 2773 } 2774 return (0); 2775} 2776 2777static int 2778initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2779 RtldLockState *lockstate) 2780{ 2781 Objlist_Entry *elm; 2782 2783 STAILQ_FOREACH(elm, list, link) { 2784 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2785 lockstate) == -1) 2786 return (-1); 2787 } 2788 return (0); 2789} 2790 2791/* 2792 * Cleanup procedure. It will be called (by the atexit mechanism) just 2793 * before the process exits. 2794 */ 2795static void 2796rtld_exit(void) 2797{ 2798 RtldLockState lockstate; 2799 2800 wlock_acquire(rtld_bind_lock, &lockstate); 2801 dbg("rtld_exit()"); 2802 objlist_call_fini(&list_fini, NULL, &lockstate); 2803 /* No need to remove the items from the list, since we are exiting. */ 2804 if (!libmap_disable) 2805 lm_fini(); 2806 lock_release(rtld_bind_lock, &lockstate); 2807} 2808 2809/* 2810 * Iterate over a search path, translate each element, and invoke the 2811 * callback on the result. 2812 */ 2813static void * 2814path_enumerate(const char *path, path_enum_proc callback, void *arg) 2815{ 2816 const char *trans; 2817 if (path == NULL) 2818 return (NULL); 2819 2820 path += strspn(path, ":;"); 2821 while (*path != '\0') { 2822 size_t len; 2823 char *res; 2824 2825 len = strcspn(path, ":;"); 2826 trans = lm_findn(NULL, path, len); 2827 if (trans) 2828 res = callback(trans, strlen(trans), arg); 2829 else 2830 res = callback(path, len, arg); 2831 2832 if (res != NULL) 2833 return (res); 2834 2835 path += len; 2836 path += strspn(path, ":;"); 2837 } 2838 2839 return (NULL); 2840} 2841 2842struct try_library_args { 2843 const char *name; 2844 size_t namelen; 2845 char *buffer; 2846 size_t buflen; 2847}; 2848 2849static void * 2850try_library_path(const char *dir, size_t dirlen, void *param) 2851{ 2852 struct try_library_args *arg; 2853 2854 arg = param; 2855 if (*dir == '/' || trust) { 2856 char *pathname; 2857 2858 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2859 return (NULL); 2860 2861 pathname = arg->buffer; 2862 strncpy(pathname, dir, dirlen); 2863 pathname[dirlen] = '/'; 2864 strcpy(pathname + dirlen + 1, arg->name); 2865 2866 dbg(" Trying \"%s\"", pathname); 2867 if (access(pathname, F_OK) == 0) { /* We found it */ 2868 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2869 strcpy(pathname, arg->buffer); 2870 return (pathname); 2871 } 2872 } 2873 return (NULL); 2874} 2875 2876static char * 2877search_library_path(const char *name, const char *path) 2878{ 2879 char *p; 2880 struct try_library_args arg; 2881 2882 if (path == NULL) 2883 return NULL; 2884 2885 arg.name = name; 2886 arg.namelen = strlen(name); 2887 arg.buffer = xmalloc(PATH_MAX); 2888 arg.buflen = PATH_MAX; 2889 2890 p = path_enumerate(path, try_library_path, &arg); 2891 2892 free(arg.buffer); 2893 2894 return (p); 2895} 2896 2897int 2898dlclose(void *handle) 2899{ 2900 Obj_Entry *root; 2901 RtldLockState lockstate; 2902 2903 wlock_acquire(rtld_bind_lock, &lockstate); 2904 root = dlcheck(handle); 2905 if (root == NULL) { 2906 lock_release(rtld_bind_lock, &lockstate); 2907 return -1; 2908 } 2909 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2910 root->path); 2911 2912 /* Unreference the object and its dependencies. */ 2913 root->dl_refcount--; 2914 2915 if (root->refcount == 1) { 2916 /* 2917 * The object will be no longer referenced, so we must unload it. 2918 * First, call the fini functions. 2919 */ 2920 objlist_call_fini(&list_fini, root, &lockstate); 2921 2922 unref_dag(root); 2923 2924 /* Finish cleaning up the newly-unreferenced objects. */ 2925 GDB_STATE(RT_DELETE,&root->linkmap); 2926 unload_object(root); 2927 GDB_STATE(RT_CONSISTENT,NULL); 2928 } else 2929 unref_dag(root); 2930 2931 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2932 lock_release(rtld_bind_lock, &lockstate); 2933 return 0; 2934} 2935 2936char * 2937dlerror(void) 2938{ 2939 char *msg = error_message; 2940 error_message = NULL; 2941 return msg; 2942} 2943 2944/* 2945 * This function is deprecated and has no effect. 2946 */ 2947void 2948dllockinit(void *context, 2949 void *(*lock_create)(void *context), 2950 void (*rlock_acquire)(void *lock), 2951 void (*wlock_acquire)(void *lock), 2952 void (*lock_release)(void *lock), 2953 void (*lock_destroy)(void *lock), 2954 void (*context_destroy)(void *context)) 2955{ 2956 static void *cur_context; 2957 static void (*cur_context_destroy)(void *); 2958 2959 /* Just destroy the context from the previous call, if necessary. */ 2960 if (cur_context_destroy != NULL) 2961 cur_context_destroy(cur_context); 2962 cur_context = context; 2963 cur_context_destroy = context_destroy; 2964} 2965 2966void * 2967dlopen(const char *name, int mode) 2968{ 2969 2970 return (rtld_dlopen(name, -1, mode)); 2971} 2972 2973void * 2974fdlopen(int fd, int mode) 2975{ 2976 2977 return (rtld_dlopen(NULL, fd, mode)); 2978} 2979 2980static void * 2981rtld_dlopen(const char *name, int fd, int mode) 2982{ 2983 RtldLockState lockstate; 2984 int lo_flags; 2985 2986 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2987 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2988 if (ld_tracing != NULL) { 2989 rlock_acquire(rtld_bind_lock, &lockstate); 2990 if (sigsetjmp(lockstate.env, 0) != 0) 2991 lock_upgrade(rtld_bind_lock, &lockstate); 2992 environ = (char **)*get_program_var_addr("environ", &lockstate); 2993 lock_release(rtld_bind_lock, &lockstate); 2994 } 2995 lo_flags = RTLD_LO_DLOPEN; 2996 if (mode & RTLD_NODELETE) 2997 lo_flags |= RTLD_LO_NODELETE; 2998 if (mode & RTLD_NOLOAD) 2999 lo_flags |= RTLD_LO_NOLOAD; 3000 if (ld_tracing != NULL) 3001 lo_flags |= RTLD_LO_TRACE; 3002 3003 return (dlopen_object(name, fd, obj_main, lo_flags, 3004 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3005} 3006 3007static void 3008dlopen_cleanup(Obj_Entry *obj) 3009{ 3010 3011 obj->dl_refcount--; 3012 unref_dag(obj); 3013 if (obj->refcount == 0) 3014 unload_object(obj); 3015} 3016 3017static Obj_Entry * 3018dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3019 int mode, RtldLockState *lockstate) 3020{ 3021 Obj_Entry *old_obj_tail; 3022 Obj_Entry *obj; 3023 Objlist initlist; 3024 RtldLockState mlockstate; 3025 int result; 3026 3027 objlist_init(&initlist); 3028 3029 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3030 wlock_acquire(rtld_bind_lock, &mlockstate); 3031 lockstate = &mlockstate; 3032 } 3033 GDB_STATE(RT_ADD,NULL); 3034 3035 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3036 obj = NULL; 3037 if (name == NULL && fd == -1) { 3038 obj = obj_main; 3039 obj->refcount++; 3040 } else { 3041 obj = load_object(name, fd, refobj, lo_flags); 3042 } 3043 3044 if (obj) { 3045 obj->dl_refcount++; 3046 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3047 objlist_push_tail(&list_global, obj); 3048 if (globallist_next(old_obj_tail) != NULL) { 3049 /* We loaded something new. */ 3050 assert(globallist_next(old_obj_tail) == obj); 3051 result = load_needed_objects(obj, 3052 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3053 init_dag(obj); 3054 ref_dag(obj); 3055 if (result != -1) 3056 result = rtld_verify_versions(&obj->dagmembers); 3057 if (result != -1 && ld_tracing) 3058 goto trace; 3059 if (result == -1 || relocate_object_dag(obj, 3060 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3061 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3062 lockstate) == -1) { 3063 dlopen_cleanup(obj); 3064 obj = NULL; 3065 } else if (lo_flags & RTLD_LO_EARLY) { 3066 /* 3067 * Do not call the init functions for early loaded 3068 * filtees. The image is still not initialized enough 3069 * for them to work. 3070 * 3071 * Our object is found by the global object list and 3072 * will be ordered among all init calls done right 3073 * before transferring control to main. 3074 */ 3075 } else { 3076 /* Make list of init functions to call. */ 3077 initlist_add_objects(obj, obj, &initlist); 3078 } 3079 /* 3080 * Process all no_delete or global objects here, given 3081 * them own DAGs to prevent their dependencies from being 3082 * unloaded. This has to be done after we have loaded all 3083 * of the dependencies, so that we do not miss any. 3084 */ 3085 if (obj != NULL) 3086 process_z(obj); 3087 } else { 3088 /* 3089 * Bump the reference counts for objects on this DAG. If 3090 * this is the first dlopen() call for the object that was 3091 * already loaded as a dependency, initialize the dag 3092 * starting at it. 3093 */ 3094 init_dag(obj); 3095 ref_dag(obj); 3096 3097 if ((lo_flags & RTLD_LO_TRACE) != 0) 3098 goto trace; 3099 } 3100 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3101 obj->z_nodelete) && !obj->ref_nodel) { 3102 dbg("obj %s nodelete", obj->path); 3103 ref_dag(obj); 3104 obj->z_nodelete = obj->ref_nodel = true; 3105 } 3106 } 3107 3108 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3109 name); 3110 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3111 3112 if (!(lo_flags & RTLD_LO_EARLY)) { 3113 map_stacks_exec(lockstate); 3114 } 3115 3116 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3117 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3118 lockstate) == -1) { 3119 objlist_clear(&initlist); 3120 dlopen_cleanup(obj); 3121 if (lockstate == &mlockstate) 3122 lock_release(rtld_bind_lock, lockstate); 3123 return (NULL); 3124 } 3125 3126 if (!(lo_flags & RTLD_LO_EARLY)) { 3127 /* Call the init functions. */ 3128 objlist_call_init(&initlist, lockstate); 3129 } 3130 objlist_clear(&initlist); 3131 if (lockstate == &mlockstate) 3132 lock_release(rtld_bind_lock, lockstate); 3133 return obj; 3134trace: 3135 trace_loaded_objects(obj); 3136 if (lockstate == &mlockstate) 3137 lock_release(rtld_bind_lock, lockstate); 3138 exit(0); 3139} 3140 3141static void * 3142do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3143 int flags) 3144{ 3145 DoneList donelist; 3146 const Obj_Entry *obj, *defobj; 3147 const Elf_Sym *def; 3148 SymLook req; 3149 RtldLockState lockstate; 3150#ifndef __ia64__ 3151 tls_index ti; 3152#endif 3153 void *sym; 3154 int res; 3155 3156 def = NULL; 3157 defobj = NULL; 3158 symlook_init(&req, name); 3159 req.ventry = ve; 3160 req.flags = flags | SYMLOOK_IN_PLT; 3161 req.lockstate = &lockstate; 3162 3163 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3164 rlock_acquire(rtld_bind_lock, &lockstate); 3165 if (sigsetjmp(lockstate.env, 0) != 0) 3166 lock_upgrade(rtld_bind_lock, &lockstate); 3167 if (handle == NULL || handle == RTLD_NEXT || 3168 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3169 3170 if ((obj = obj_from_addr(retaddr)) == NULL) { 3171 _rtld_error("Cannot determine caller's shared object"); 3172 lock_release(rtld_bind_lock, &lockstate); 3173 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3174 return NULL; 3175 } 3176 if (handle == NULL) { /* Just the caller's shared object. */ 3177 res = symlook_obj(&req, obj); 3178 if (res == 0) { 3179 def = req.sym_out; 3180 defobj = req.defobj_out; 3181 } 3182 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3183 handle == RTLD_SELF) { /* ... caller included */ 3184 if (handle == RTLD_NEXT) 3185 obj = globallist_next(obj); 3186 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3187 if (obj->marker) 3188 continue; 3189 res = symlook_obj(&req, obj); 3190 if (res == 0) { 3191 if (def == NULL || 3192 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3193 def = req.sym_out; 3194 defobj = req.defobj_out; 3195 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3196 break; 3197 } 3198 } 3199 } 3200 /* 3201 * Search the dynamic linker itself, and possibly resolve the 3202 * symbol from there. This is how the application links to 3203 * dynamic linker services such as dlopen. 3204 */ 3205 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3206 res = symlook_obj(&req, &obj_rtld); 3207 if (res == 0) { 3208 def = req.sym_out; 3209 defobj = req.defobj_out; 3210 } 3211 } 3212 } else { 3213 assert(handle == RTLD_DEFAULT); 3214 res = symlook_default(&req, obj); 3215 if (res == 0) { 3216 defobj = req.defobj_out; 3217 def = req.sym_out; 3218 } 3219 } 3220 } else { 3221 if ((obj = dlcheck(handle)) == NULL) { 3222 lock_release(rtld_bind_lock, &lockstate); 3223 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3224 return NULL; 3225 } 3226 3227 donelist_init(&donelist); 3228 if (obj->mainprog) { 3229 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3230 res = symlook_global(&req, &donelist); 3231 if (res == 0) { 3232 def = req.sym_out; 3233 defobj = req.defobj_out; 3234 } 3235 /* 3236 * Search the dynamic linker itself, and possibly resolve the 3237 * symbol from there. This is how the application links to 3238 * dynamic linker services such as dlopen. 3239 */ 3240 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3241 res = symlook_obj(&req, &obj_rtld); 3242 if (res == 0) { 3243 def = req.sym_out; 3244 defobj = req.defobj_out; 3245 } 3246 } 3247 } 3248 else { 3249 /* Search the whole DAG rooted at the given object. */ 3250 res = symlook_list(&req, &obj->dagmembers, &donelist); 3251 if (res == 0) { 3252 def = req.sym_out; 3253 defobj = req.defobj_out; 3254 } 3255 } 3256 } 3257 3258 if (def != NULL) { 3259 lock_release(rtld_bind_lock, &lockstate); 3260 3261 /* 3262 * The value required by the caller is derived from the value 3263 * of the symbol. For the ia64 architecture, we need to 3264 * construct a function descriptor which the caller can use to 3265 * call the function with the right 'gp' value. For other 3266 * architectures and for non-functions, the value is simply 3267 * the relocated value of the symbol. 3268 */ 3269 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3270 sym = make_function_pointer(def, defobj); 3271 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3272 sym = rtld_resolve_ifunc(defobj, def); 3273 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3274#ifdef __ia64__ 3275 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3276#else 3277 ti.ti_module = defobj->tlsindex; 3278 ti.ti_offset = def->st_value; 3279 sym = __tls_get_addr(&ti); 3280#endif 3281 } else 3282 sym = defobj->relocbase + def->st_value; 3283 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3284 return (sym); 3285 } 3286 3287 _rtld_error("Undefined symbol \"%s\"", name); 3288 lock_release(rtld_bind_lock, &lockstate); 3289 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3290 return NULL; 3291} 3292 3293void * 3294dlsym(void *handle, const char *name) 3295{ 3296 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3297 SYMLOOK_DLSYM); 3298} 3299 3300dlfunc_t 3301dlfunc(void *handle, const char *name) 3302{ 3303 union { 3304 void *d; 3305 dlfunc_t f; 3306 } rv; 3307 3308 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3309 SYMLOOK_DLSYM); 3310 return (rv.f); 3311} 3312 3313void * 3314dlvsym(void *handle, const char *name, const char *version) 3315{ 3316 Ver_Entry ventry; 3317 3318 ventry.name = version; 3319 ventry.file = NULL; 3320 ventry.hash = elf_hash(version); 3321 ventry.flags= 0; 3322 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3323 SYMLOOK_DLSYM); 3324} 3325 3326int 3327_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3328{ 3329 const Obj_Entry *obj; 3330 RtldLockState lockstate; 3331 3332 rlock_acquire(rtld_bind_lock, &lockstate); 3333 obj = obj_from_addr(addr); 3334 if (obj == NULL) { 3335 _rtld_error("No shared object contains address"); 3336 lock_release(rtld_bind_lock, &lockstate); 3337 return (0); 3338 } 3339 rtld_fill_dl_phdr_info(obj, phdr_info); 3340 lock_release(rtld_bind_lock, &lockstate); 3341 return (1); 3342} 3343 3344int 3345dladdr(const void *addr, Dl_info *info) 3346{ 3347 const Obj_Entry *obj; 3348 const Elf_Sym *def; 3349 void *symbol_addr; 3350 unsigned long symoffset; 3351 RtldLockState lockstate; 3352 3353 rlock_acquire(rtld_bind_lock, &lockstate); 3354 obj = obj_from_addr(addr); 3355 if (obj == NULL) { 3356 _rtld_error("No shared object contains address"); 3357 lock_release(rtld_bind_lock, &lockstate); 3358 return 0; 3359 } 3360 info->dli_fname = obj->path; 3361 info->dli_fbase = obj->mapbase; 3362 info->dli_saddr = (void *)0; 3363 info->dli_sname = NULL; 3364 3365 /* 3366 * Walk the symbol list looking for the symbol whose address is 3367 * closest to the address sent in. 3368 */ 3369 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3370 def = obj->symtab + symoffset; 3371 3372 /* 3373 * For skip the symbol if st_shndx is either SHN_UNDEF or 3374 * SHN_COMMON. 3375 */ 3376 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3377 continue; 3378 3379 /* 3380 * If the symbol is greater than the specified address, or if it 3381 * is further away from addr than the current nearest symbol, 3382 * then reject it. 3383 */ 3384 symbol_addr = obj->relocbase + def->st_value; 3385 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3386 continue; 3387 3388 /* Update our idea of the nearest symbol. */ 3389 info->dli_sname = obj->strtab + def->st_name; 3390 info->dli_saddr = symbol_addr; 3391 3392 /* Exact match? */ 3393 if (info->dli_saddr == addr) 3394 break; 3395 } 3396 lock_release(rtld_bind_lock, &lockstate); 3397 return 1; 3398} 3399 3400int 3401dlinfo(void *handle, int request, void *p) 3402{ 3403 const Obj_Entry *obj; 3404 RtldLockState lockstate; 3405 int error; 3406 3407 rlock_acquire(rtld_bind_lock, &lockstate); 3408 3409 if (handle == NULL || handle == RTLD_SELF) { 3410 void *retaddr; 3411 3412 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3413 if ((obj = obj_from_addr(retaddr)) == NULL) 3414 _rtld_error("Cannot determine caller's shared object"); 3415 } else 3416 obj = dlcheck(handle); 3417 3418 if (obj == NULL) { 3419 lock_release(rtld_bind_lock, &lockstate); 3420 return (-1); 3421 } 3422 3423 error = 0; 3424 switch (request) { 3425 case RTLD_DI_LINKMAP: 3426 *((struct link_map const **)p) = &obj->linkmap; 3427 break; 3428 case RTLD_DI_ORIGIN: 3429 error = rtld_dirname(obj->path, p); 3430 break; 3431 3432 case RTLD_DI_SERINFOSIZE: 3433 case RTLD_DI_SERINFO: 3434 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3435 break; 3436 3437 default: 3438 _rtld_error("Invalid request %d passed to dlinfo()", request); 3439 error = -1; 3440 } 3441 3442 lock_release(rtld_bind_lock, &lockstate); 3443 3444 return (error); 3445} 3446 3447static void 3448rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3449{ 3450 3451 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3452 phdr_info->dlpi_name = obj->path; 3453 phdr_info->dlpi_phdr = obj->phdr; 3454 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3455 phdr_info->dlpi_tls_modid = obj->tlsindex; 3456 phdr_info->dlpi_tls_data = obj->tlsinit; 3457 phdr_info->dlpi_adds = obj_loads; 3458 phdr_info->dlpi_subs = obj_loads - obj_count; 3459} 3460 3461int 3462dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3463{ 3464 struct dl_phdr_info phdr_info; 3465 Obj_Entry *obj, marker; 3466 RtldLockState bind_lockstate, phdr_lockstate; 3467 int error; 3468 3469 bzero(&marker, sizeof(marker)); 3470 marker.marker = true; 3471 error = 0; 3472 3473 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3474 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3475 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3476 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3477 rtld_fill_dl_phdr_info(obj, &phdr_info); 3478 lock_release(rtld_bind_lock, &bind_lockstate); 3479 3480 error = callback(&phdr_info, sizeof phdr_info, param); 3481 3482 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3483 obj = globallist_next(&marker); 3484 TAILQ_REMOVE(&obj_list, &marker, next); 3485 if (error != 0) { 3486 lock_release(rtld_bind_lock, &bind_lockstate); 3487 lock_release(rtld_phdr_lock, &phdr_lockstate); 3488 return (error); 3489 } 3490 } 3491 3492 if (error == 0) { 3493 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3494 lock_release(rtld_bind_lock, &bind_lockstate); 3495 error = callback(&phdr_info, sizeof(phdr_info), param); 3496 } 3497 lock_release(rtld_phdr_lock, &phdr_lockstate); 3498 return (error); 3499} 3500 3501static void * 3502fill_search_info(const char *dir, size_t dirlen, void *param) 3503{ 3504 struct fill_search_info_args *arg; 3505 3506 arg = param; 3507 3508 if (arg->request == RTLD_DI_SERINFOSIZE) { 3509 arg->serinfo->dls_cnt ++; 3510 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3511 } else { 3512 struct dl_serpath *s_entry; 3513 3514 s_entry = arg->serpath; 3515 s_entry->dls_name = arg->strspace; 3516 s_entry->dls_flags = arg->flags; 3517 3518 strncpy(arg->strspace, dir, dirlen); 3519 arg->strspace[dirlen] = '\0'; 3520 3521 arg->strspace += dirlen + 1; 3522 arg->serpath++; 3523 } 3524 3525 return (NULL); 3526} 3527 3528static int 3529do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3530{ 3531 struct dl_serinfo _info; 3532 struct fill_search_info_args args; 3533 3534 args.request = RTLD_DI_SERINFOSIZE; 3535 args.serinfo = &_info; 3536 3537 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3538 _info.dls_cnt = 0; 3539 3540 path_enumerate(obj->rpath, fill_search_info, &args); 3541 path_enumerate(ld_library_path, fill_search_info, &args); 3542 path_enumerate(obj->runpath, fill_search_info, &args); 3543 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3544 if (!obj->z_nodeflib) 3545 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3546 3547 3548 if (request == RTLD_DI_SERINFOSIZE) { 3549 info->dls_size = _info.dls_size; 3550 info->dls_cnt = _info.dls_cnt; 3551 return (0); 3552 } 3553 3554 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3555 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3556 return (-1); 3557 } 3558 3559 args.request = RTLD_DI_SERINFO; 3560 args.serinfo = info; 3561 args.serpath = &info->dls_serpath[0]; 3562 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3563 3564 args.flags = LA_SER_RUNPATH; 3565 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3566 return (-1); 3567 3568 args.flags = LA_SER_LIBPATH; 3569 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3570 return (-1); 3571 3572 args.flags = LA_SER_RUNPATH; 3573 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3574 return (-1); 3575 3576 args.flags = LA_SER_CONFIG; 3577 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3578 != NULL) 3579 return (-1); 3580 3581 args.flags = LA_SER_DEFAULT; 3582 if (!obj->z_nodeflib && 3583 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3584 return (-1); 3585 return (0); 3586} 3587 3588static int 3589rtld_dirname(const char *path, char *bname) 3590{ 3591 const char *endp; 3592 3593 /* Empty or NULL string gets treated as "." */ 3594 if (path == NULL || *path == '\0') { 3595 bname[0] = '.'; 3596 bname[1] = '\0'; 3597 return (0); 3598 } 3599 3600 /* Strip trailing slashes */ 3601 endp = path + strlen(path) - 1; 3602 while (endp > path && *endp == '/') 3603 endp--; 3604 3605 /* Find the start of the dir */ 3606 while (endp > path && *endp != '/') 3607 endp--; 3608 3609 /* Either the dir is "/" or there are no slashes */ 3610 if (endp == path) { 3611 bname[0] = *endp == '/' ? '/' : '.'; 3612 bname[1] = '\0'; 3613 return (0); 3614 } else { 3615 do { 3616 endp--; 3617 } while (endp > path && *endp == '/'); 3618 } 3619 3620 if (endp - path + 2 > PATH_MAX) 3621 { 3622 _rtld_error("Filename is too long: %s", path); 3623 return(-1); 3624 } 3625 3626 strncpy(bname, path, endp - path + 1); 3627 bname[endp - path + 1] = '\0'; 3628 return (0); 3629} 3630 3631static int 3632rtld_dirname_abs(const char *path, char *base) 3633{ 3634 char *last; 3635 3636 if (realpath(path, base) == NULL) 3637 return (-1); 3638 dbg("%s -> %s", path, base); 3639 last = strrchr(base, '/'); 3640 if (last == NULL) 3641 return (-1); 3642 if (last != base) 3643 *last = '\0'; 3644 return (0); 3645} 3646 3647static void 3648linkmap_add(Obj_Entry *obj) 3649{ 3650 struct link_map *l = &obj->linkmap; 3651 struct link_map *prev; 3652 3653 obj->linkmap.l_name = obj->path; 3654 obj->linkmap.l_addr = obj->mapbase; 3655 obj->linkmap.l_ld = obj->dynamic; 3656#ifdef __mips__ 3657 /* GDB needs load offset on MIPS to use the symbols */ 3658 obj->linkmap.l_offs = obj->relocbase; 3659#endif 3660 3661 if (r_debug.r_map == NULL) { 3662 r_debug.r_map = l; 3663 return; 3664 } 3665 3666 /* 3667 * Scan to the end of the list, but not past the entry for the 3668 * dynamic linker, which we want to keep at the very end. 3669 */ 3670 for (prev = r_debug.r_map; 3671 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3672 prev = prev->l_next) 3673 ; 3674 3675 /* Link in the new entry. */ 3676 l->l_prev = prev; 3677 l->l_next = prev->l_next; 3678 if (l->l_next != NULL) 3679 l->l_next->l_prev = l; 3680 prev->l_next = l; 3681} 3682 3683static void 3684linkmap_delete(Obj_Entry *obj) 3685{ 3686 struct link_map *l = &obj->linkmap; 3687 3688 if (l->l_prev == NULL) { 3689 if ((r_debug.r_map = l->l_next) != NULL) 3690 l->l_next->l_prev = NULL; 3691 return; 3692 } 3693 3694 if ((l->l_prev->l_next = l->l_next) != NULL) 3695 l->l_next->l_prev = l->l_prev; 3696} 3697 3698/* 3699 * Function for the debugger to set a breakpoint on to gain control. 3700 * 3701 * The two parameters allow the debugger to easily find and determine 3702 * what the runtime loader is doing and to whom it is doing it. 3703 * 3704 * When the loadhook trap is hit (r_debug_state, set at program 3705 * initialization), the arguments can be found on the stack: 3706 * 3707 * +8 struct link_map *m 3708 * +4 struct r_debug *rd 3709 * +0 RetAddr 3710 */ 3711void 3712r_debug_state(struct r_debug* rd, struct link_map *m) 3713{ 3714 /* 3715 * The following is a hack to force the compiler to emit calls to 3716 * this function, even when optimizing. If the function is empty, 3717 * the compiler is not obliged to emit any code for calls to it, 3718 * even when marked __noinline. However, gdb depends on those 3719 * calls being made. 3720 */ 3721 __compiler_membar(); 3722} 3723 3724/* 3725 * A function called after init routines have completed. This can be used to 3726 * break before a program's entry routine is called, and can be used when 3727 * main is not available in the symbol table. 3728 */ 3729void 3730_r_debug_postinit(struct link_map *m) 3731{ 3732 3733 /* See r_debug_state(). */ 3734 __compiler_membar(); 3735} 3736 3737/* 3738 * Get address of the pointer variable in the main program. 3739 * Prefer non-weak symbol over the weak one. 3740 */ 3741static const void ** 3742get_program_var_addr(const char *name, RtldLockState *lockstate) 3743{ 3744 SymLook req; 3745 DoneList donelist; 3746 3747 symlook_init(&req, name); 3748 req.lockstate = lockstate; 3749 donelist_init(&donelist); 3750 if (symlook_global(&req, &donelist) != 0) 3751 return (NULL); 3752 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3753 return ((const void **)make_function_pointer(req.sym_out, 3754 req.defobj_out)); 3755 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3756 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3757 else 3758 return ((const void **)(req.defobj_out->relocbase + 3759 req.sym_out->st_value)); 3760} 3761 3762/* 3763 * Set a pointer variable in the main program to the given value. This 3764 * is used to set key variables such as "environ" before any of the 3765 * init functions are called. 3766 */ 3767static void 3768set_program_var(const char *name, const void *value) 3769{ 3770 const void **addr; 3771 3772 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3773 dbg("\"%s\": *%p <-- %p", name, addr, value); 3774 *addr = value; 3775 } 3776} 3777 3778/* 3779 * Search the global objects, including dependencies and main object, 3780 * for the given symbol. 3781 */ 3782static int 3783symlook_global(SymLook *req, DoneList *donelist) 3784{ 3785 SymLook req1; 3786 const Objlist_Entry *elm; 3787 int res; 3788 3789 symlook_init_from_req(&req1, req); 3790 3791 /* Search all objects loaded at program start up. */ 3792 if (req->defobj_out == NULL || 3793 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3794 res = symlook_list(&req1, &list_main, donelist); 3795 if (res == 0 && (req->defobj_out == NULL || 3796 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3797 req->sym_out = req1.sym_out; 3798 req->defobj_out = req1.defobj_out; 3799 assert(req->defobj_out != NULL); 3800 } 3801 } 3802 3803 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3804 STAILQ_FOREACH(elm, &list_global, link) { 3805 if (req->defobj_out != NULL && 3806 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3807 break; 3808 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3809 if (res == 0 && (req->defobj_out == NULL || 3810 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3811 req->sym_out = req1.sym_out; 3812 req->defobj_out = req1.defobj_out; 3813 assert(req->defobj_out != NULL); 3814 } 3815 } 3816 3817 return (req->sym_out != NULL ? 0 : ESRCH); 3818} 3819 3820/* 3821 * Given a symbol name in a referencing object, find the corresponding 3822 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3823 * no definition was found. Returns a pointer to the Obj_Entry of the 3824 * defining object via the reference parameter DEFOBJ_OUT. 3825 */ 3826static int 3827symlook_default(SymLook *req, const Obj_Entry *refobj) 3828{ 3829 DoneList donelist; 3830 const Objlist_Entry *elm; 3831 SymLook req1; 3832 int res; 3833 3834 donelist_init(&donelist); 3835 symlook_init_from_req(&req1, req); 3836 3837 /* Look first in the referencing object if linked symbolically. */ 3838 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3839 res = symlook_obj(&req1, refobj); 3840 if (res == 0) { 3841 req->sym_out = req1.sym_out; 3842 req->defobj_out = req1.defobj_out; 3843 assert(req->defobj_out != NULL); 3844 } 3845 } 3846 3847 symlook_global(req, &donelist); 3848 3849 /* Search all dlopened DAGs containing the referencing object. */ 3850 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3851 if (req->sym_out != NULL && 3852 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3853 break; 3854 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3855 if (res == 0 && (req->sym_out == NULL || 3856 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3857 req->sym_out = req1.sym_out; 3858 req->defobj_out = req1.defobj_out; 3859 assert(req->defobj_out != NULL); 3860 } 3861 } 3862 3863 /* 3864 * Search the dynamic linker itself, and possibly resolve the 3865 * symbol from there. This is how the application links to 3866 * dynamic linker services such as dlopen. 3867 */ 3868 if (req->sym_out == NULL || 3869 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3870 res = symlook_obj(&req1, &obj_rtld); 3871 if (res == 0) { 3872 req->sym_out = req1.sym_out; 3873 req->defobj_out = req1.defobj_out; 3874 assert(req->defobj_out != NULL); 3875 } 3876 } 3877 3878 return (req->sym_out != NULL ? 0 : ESRCH); 3879} 3880 3881static int 3882symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3883{ 3884 const Elf_Sym *def; 3885 const Obj_Entry *defobj; 3886 const Objlist_Entry *elm; 3887 SymLook req1; 3888 int res; 3889 3890 def = NULL; 3891 defobj = NULL; 3892 STAILQ_FOREACH(elm, objlist, link) { 3893 if (donelist_check(dlp, elm->obj)) 3894 continue; 3895 symlook_init_from_req(&req1, req); 3896 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3897 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3898 def = req1.sym_out; 3899 defobj = req1.defobj_out; 3900 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3901 break; 3902 } 3903 } 3904 } 3905 if (def != NULL) { 3906 req->sym_out = def; 3907 req->defobj_out = defobj; 3908 return (0); 3909 } 3910 return (ESRCH); 3911} 3912 3913/* 3914 * Search the chain of DAGS cointed to by the given Needed_Entry 3915 * for a symbol of the given name. Each DAG is scanned completely 3916 * before advancing to the next one. Returns a pointer to the symbol, 3917 * or NULL if no definition was found. 3918 */ 3919static int 3920symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3921{ 3922 const Elf_Sym *def; 3923 const Needed_Entry *n; 3924 const Obj_Entry *defobj; 3925 SymLook req1; 3926 int res; 3927 3928 def = NULL; 3929 defobj = NULL; 3930 symlook_init_from_req(&req1, req); 3931 for (n = needed; n != NULL; n = n->next) { 3932 if (n->obj == NULL || 3933 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3934 continue; 3935 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3936 def = req1.sym_out; 3937 defobj = req1.defobj_out; 3938 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3939 break; 3940 } 3941 } 3942 if (def != NULL) { 3943 req->sym_out = def; 3944 req->defobj_out = defobj; 3945 return (0); 3946 } 3947 return (ESRCH); 3948} 3949 3950/* 3951 * Search the symbol table of a single shared object for a symbol of 3952 * the given name and version, if requested. Returns a pointer to the 3953 * symbol, or NULL if no definition was found. If the object is 3954 * filter, return filtered symbol from filtee. 3955 * 3956 * The symbol's hash value is passed in for efficiency reasons; that 3957 * eliminates many recomputations of the hash value. 3958 */ 3959int 3960symlook_obj(SymLook *req, const Obj_Entry *obj) 3961{ 3962 DoneList donelist; 3963 SymLook req1; 3964 int flags, res, mres; 3965 3966 /* 3967 * If there is at least one valid hash at this point, we prefer to 3968 * use the faster GNU version if available. 3969 */ 3970 if (obj->valid_hash_gnu) 3971 mres = symlook_obj1_gnu(req, obj); 3972 else if (obj->valid_hash_sysv) 3973 mres = symlook_obj1_sysv(req, obj); 3974 else 3975 return (EINVAL); 3976 3977 if (mres == 0) { 3978 if (obj->needed_filtees != NULL) { 3979 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3980 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3981 donelist_init(&donelist); 3982 symlook_init_from_req(&req1, req); 3983 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3984 if (res == 0) { 3985 req->sym_out = req1.sym_out; 3986 req->defobj_out = req1.defobj_out; 3987 } 3988 return (res); 3989 } 3990 if (obj->needed_aux_filtees != NULL) { 3991 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3992 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3993 donelist_init(&donelist); 3994 symlook_init_from_req(&req1, req); 3995 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3996 if (res == 0) { 3997 req->sym_out = req1.sym_out; 3998 req->defobj_out = req1.defobj_out; 3999 return (res); 4000 } 4001 } 4002 } 4003 return (mres); 4004} 4005 4006/* Symbol match routine common to both hash functions */ 4007static bool 4008matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4009 const unsigned long symnum) 4010{ 4011 Elf_Versym verndx; 4012 const Elf_Sym *symp; 4013 const char *strp; 4014 4015 symp = obj->symtab + symnum; 4016 strp = obj->strtab + symp->st_name; 4017 4018 switch (ELF_ST_TYPE(symp->st_info)) { 4019 case STT_FUNC: 4020 case STT_NOTYPE: 4021 case STT_OBJECT: 4022 case STT_COMMON: 4023 case STT_GNU_IFUNC: 4024 if (symp->st_value == 0) 4025 return (false); 4026 /* fallthrough */ 4027 case STT_TLS: 4028 if (symp->st_shndx != SHN_UNDEF) 4029 break; 4030#ifndef __mips__ 4031 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4032 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4033 break; 4034 /* fallthrough */ 4035#endif 4036 default: 4037 return (false); 4038 } 4039 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4040 return (false); 4041 4042 if (req->ventry == NULL) { 4043 if (obj->versyms != NULL) { 4044 verndx = VER_NDX(obj->versyms[symnum]); 4045 if (verndx > obj->vernum) { 4046 _rtld_error( 4047 "%s: symbol %s references wrong version %d", 4048 obj->path, obj->strtab + symnum, verndx); 4049 return (false); 4050 } 4051 /* 4052 * If we are not called from dlsym (i.e. this 4053 * is a normal relocation from unversioned 4054 * binary), accept the symbol immediately if 4055 * it happens to have first version after this 4056 * shared object became versioned. Otherwise, 4057 * if symbol is versioned and not hidden, 4058 * remember it. If it is the only symbol with 4059 * this name exported by the shared object, it 4060 * will be returned as a match by the calling 4061 * function. If symbol is global (verndx < 2) 4062 * accept it unconditionally. 4063 */ 4064 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4065 verndx == VER_NDX_GIVEN) { 4066 result->sym_out = symp; 4067 return (true); 4068 } 4069 else if (verndx >= VER_NDX_GIVEN) { 4070 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4071 == 0) { 4072 if (result->vsymp == NULL) 4073 result->vsymp = symp; 4074 result->vcount++; 4075 } 4076 return (false); 4077 } 4078 } 4079 result->sym_out = symp; 4080 return (true); 4081 } 4082 if (obj->versyms == NULL) { 4083 if (object_match_name(obj, req->ventry->name)) { 4084 _rtld_error("%s: object %s should provide version %s " 4085 "for symbol %s", obj_rtld.path, obj->path, 4086 req->ventry->name, obj->strtab + symnum); 4087 return (false); 4088 } 4089 } else { 4090 verndx = VER_NDX(obj->versyms[symnum]); 4091 if (verndx > obj->vernum) { 4092 _rtld_error("%s: symbol %s references wrong version %d", 4093 obj->path, obj->strtab + symnum, verndx); 4094 return (false); 4095 } 4096 if (obj->vertab[verndx].hash != req->ventry->hash || 4097 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4098 /* 4099 * Version does not match. Look if this is a 4100 * global symbol and if it is not hidden. If 4101 * global symbol (verndx < 2) is available, 4102 * use it. Do not return symbol if we are 4103 * called by dlvsym, because dlvsym looks for 4104 * a specific version and default one is not 4105 * what dlvsym wants. 4106 */ 4107 if ((req->flags & SYMLOOK_DLSYM) || 4108 (verndx >= VER_NDX_GIVEN) || 4109 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4110 return (false); 4111 } 4112 } 4113 result->sym_out = symp; 4114 return (true); 4115} 4116 4117/* 4118 * Search for symbol using SysV hash function. 4119 * obj->buckets is known not to be NULL at this point; the test for this was 4120 * performed with the obj->valid_hash_sysv assignment. 4121 */ 4122static int 4123symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4124{ 4125 unsigned long symnum; 4126 Sym_Match_Result matchres; 4127 4128 matchres.sym_out = NULL; 4129 matchres.vsymp = NULL; 4130 matchres.vcount = 0; 4131 4132 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4133 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4134 if (symnum >= obj->nchains) 4135 return (ESRCH); /* Bad object */ 4136 4137 if (matched_symbol(req, obj, &matchres, symnum)) { 4138 req->sym_out = matchres.sym_out; 4139 req->defobj_out = obj; 4140 return (0); 4141 } 4142 } 4143 if (matchres.vcount == 1) { 4144 req->sym_out = matchres.vsymp; 4145 req->defobj_out = obj; 4146 return (0); 4147 } 4148 return (ESRCH); 4149} 4150 4151/* Search for symbol using GNU hash function */ 4152static int 4153symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4154{ 4155 Elf_Addr bloom_word; 4156 const Elf32_Word *hashval; 4157 Elf32_Word bucket; 4158 Sym_Match_Result matchres; 4159 unsigned int h1, h2; 4160 unsigned long symnum; 4161 4162 matchres.sym_out = NULL; 4163 matchres.vsymp = NULL; 4164 matchres.vcount = 0; 4165 4166 /* Pick right bitmask word from Bloom filter array */ 4167 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4168 obj->maskwords_bm_gnu]; 4169 4170 /* Calculate modulus word size of gnu hash and its derivative */ 4171 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4172 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4173 4174 /* Filter out the "definitely not in set" queries */ 4175 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4176 return (ESRCH); 4177 4178 /* Locate hash chain and corresponding value element*/ 4179 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4180 if (bucket == 0) 4181 return (ESRCH); 4182 hashval = &obj->chain_zero_gnu[bucket]; 4183 do { 4184 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4185 symnum = hashval - obj->chain_zero_gnu; 4186 if (matched_symbol(req, obj, &matchres, symnum)) { 4187 req->sym_out = matchres.sym_out; 4188 req->defobj_out = obj; 4189 return (0); 4190 } 4191 } 4192 } while ((*hashval++ & 1) == 0); 4193 if (matchres.vcount == 1) { 4194 req->sym_out = matchres.vsymp; 4195 req->defobj_out = obj; 4196 return (0); 4197 } 4198 return (ESRCH); 4199} 4200 4201static void 4202trace_loaded_objects(Obj_Entry *obj) 4203{ 4204 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4205 int c; 4206 4207 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4208 main_local = ""; 4209 4210 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4211 fmt1 = "\t%o => %p (%x)\n"; 4212 4213 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4214 fmt2 = "\t%o (%x)\n"; 4215 4216 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4217 4218 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4219 Needed_Entry *needed; 4220 char *name, *path; 4221 bool is_lib; 4222 4223 if (obj->marker) 4224 continue; 4225 if (list_containers && obj->needed != NULL) 4226 rtld_printf("%s:\n", obj->path); 4227 for (needed = obj->needed; needed; needed = needed->next) { 4228 if (needed->obj != NULL) { 4229 if (needed->obj->traced && !list_containers) 4230 continue; 4231 needed->obj->traced = true; 4232 path = needed->obj->path; 4233 } else 4234 path = "not found"; 4235 4236 name = (char *)obj->strtab + needed->name; 4237 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4238 4239 fmt = is_lib ? fmt1 : fmt2; 4240 while ((c = *fmt++) != '\0') { 4241 switch (c) { 4242 default: 4243 rtld_putchar(c); 4244 continue; 4245 case '\\': 4246 switch (c = *fmt) { 4247 case '\0': 4248 continue; 4249 case 'n': 4250 rtld_putchar('\n'); 4251 break; 4252 case 't': 4253 rtld_putchar('\t'); 4254 break; 4255 } 4256 break; 4257 case '%': 4258 switch (c = *fmt) { 4259 case '\0': 4260 continue; 4261 case '%': 4262 default: 4263 rtld_putchar(c); 4264 break; 4265 case 'A': 4266 rtld_putstr(main_local); 4267 break; 4268 case 'a': 4269 rtld_putstr(obj_main->path); 4270 break; 4271 case 'o': 4272 rtld_putstr(name); 4273 break; 4274#if 0 4275 case 'm': 4276 rtld_printf("%d", sodp->sod_major); 4277 break; 4278 case 'n': 4279 rtld_printf("%d", sodp->sod_minor); 4280 break; 4281#endif 4282 case 'p': 4283 rtld_putstr(path); 4284 break; 4285 case 'x': 4286 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4287 0); 4288 break; 4289 } 4290 break; 4291 } 4292 ++fmt; 4293 } 4294 } 4295 } 4296} 4297 4298/* 4299 * Unload a dlopened object and its dependencies from memory and from 4300 * our data structures. It is assumed that the DAG rooted in the 4301 * object has already been unreferenced, and that the object has a 4302 * reference count of 0. 4303 */ 4304static void 4305unload_object(Obj_Entry *root) 4306{ 4307 Obj_Entry *obj, *obj1; 4308 4309 assert(root->refcount == 0); 4310 4311 /* 4312 * Pass over the DAG removing unreferenced objects from 4313 * appropriate lists. 4314 */ 4315 unlink_object(root); 4316 4317 /* Unmap all objects that are no longer referenced. */ 4318 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4319 if (obj->marker || obj->refcount != 0) 4320 continue; 4321 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4322 obj->mapsize, 0, obj->path); 4323 dbg("unloading \"%s\"", obj->path); 4324 unload_filtees(root); 4325 munmap(obj->mapbase, obj->mapsize); 4326 linkmap_delete(obj); 4327 TAILQ_REMOVE(&obj_list, obj, next); 4328 obj_count--; 4329 obj_free(obj); 4330 } 4331} 4332 4333static void 4334unlink_object(Obj_Entry *root) 4335{ 4336 Objlist_Entry *elm; 4337 4338 if (root->refcount == 0) { 4339 /* Remove the object from the RTLD_GLOBAL list. */ 4340 objlist_remove(&list_global, root); 4341 4342 /* Remove the object from all objects' DAG lists. */ 4343 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4344 objlist_remove(&elm->obj->dldags, root); 4345 if (elm->obj != root) 4346 unlink_object(elm->obj); 4347 } 4348 } 4349} 4350 4351static void 4352ref_dag(Obj_Entry *root) 4353{ 4354 Objlist_Entry *elm; 4355 4356 assert(root->dag_inited); 4357 STAILQ_FOREACH(elm, &root->dagmembers, link) 4358 elm->obj->refcount++; 4359} 4360 4361static void 4362unref_dag(Obj_Entry *root) 4363{ 4364 Objlist_Entry *elm; 4365 4366 assert(root->dag_inited); 4367 STAILQ_FOREACH(elm, &root->dagmembers, link) 4368 elm->obj->refcount--; 4369} 4370 4371/* 4372 * Common code for MD __tls_get_addr(). 4373 */ 4374static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4375static void * 4376tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4377{ 4378 Elf_Addr *newdtv, *dtv; 4379 RtldLockState lockstate; 4380 int to_copy; 4381 4382 dtv = *dtvp; 4383 /* Check dtv generation in case new modules have arrived */ 4384 if (dtv[0] != tls_dtv_generation) { 4385 wlock_acquire(rtld_bind_lock, &lockstate); 4386 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4387 to_copy = dtv[1]; 4388 if (to_copy > tls_max_index) 4389 to_copy = tls_max_index; 4390 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4391 newdtv[0] = tls_dtv_generation; 4392 newdtv[1] = tls_max_index; 4393 free(dtv); 4394 lock_release(rtld_bind_lock, &lockstate); 4395 dtv = *dtvp = newdtv; 4396 } 4397 4398 /* Dynamically allocate module TLS if necessary */ 4399 if (dtv[index + 1] == 0) { 4400 /* Signal safe, wlock will block out signals. */ 4401 wlock_acquire(rtld_bind_lock, &lockstate); 4402 if (!dtv[index + 1]) 4403 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4404 lock_release(rtld_bind_lock, &lockstate); 4405 } 4406 return ((void *)(dtv[index + 1] + offset)); 4407} 4408 4409void * 4410tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4411{ 4412 Elf_Addr *dtv; 4413 4414 dtv = *dtvp; 4415 /* Check dtv generation in case new modules have arrived */ 4416 if (__predict_true(dtv[0] == tls_dtv_generation && 4417 dtv[index + 1] != 0)) 4418 return ((void *)(dtv[index + 1] + offset)); 4419 return (tls_get_addr_slow(dtvp, index, offset)); 4420} 4421 4422#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4423 4424/* 4425 * Allocate Static TLS using the Variant I method. 4426 */ 4427void * 4428allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4429{ 4430 Obj_Entry *obj; 4431 char *tcb; 4432 Elf_Addr **tls; 4433 Elf_Addr *dtv; 4434 Elf_Addr addr; 4435 int i; 4436 4437 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4438 return (oldtcb); 4439 4440 assert(tcbsize >= TLS_TCB_SIZE); 4441 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4442 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4443 4444 if (oldtcb != NULL) { 4445 memcpy(tls, oldtcb, tls_static_space); 4446 free(oldtcb); 4447 4448 /* Adjust the DTV. */ 4449 dtv = tls[0]; 4450 for (i = 0; i < dtv[1]; i++) { 4451 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4452 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4453 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4454 } 4455 } 4456 } else { 4457 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4458 tls[0] = dtv; 4459 dtv[0] = tls_dtv_generation; 4460 dtv[1] = tls_max_index; 4461 4462 for (obj = globallist_curr(objs); obj != NULL; 4463 obj = globallist_next(obj)) { 4464 if (obj->tlsoffset > 0) { 4465 addr = (Elf_Addr)tls + obj->tlsoffset; 4466 if (obj->tlsinitsize > 0) 4467 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4468 if (obj->tlssize > obj->tlsinitsize) 4469 memset((void*) (addr + obj->tlsinitsize), 0, 4470 obj->tlssize - obj->tlsinitsize); 4471 dtv[obj->tlsindex + 1] = addr; 4472 } 4473 } 4474 } 4475 4476 return (tcb); 4477} 4478 4479void 4480free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4481{ 4482 Elf_Addr *dtv; 4483 Elf_Addr tlsstart, tlsend; 4484 int dtvsize, i; 4485 4486 assert(tcbsize >= TLS_TCB_SIZE); 4487 4488 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4489 tlsend = tlsstart + tls_static_space; 4490 4491 dtv = *(Elf_Addr **)tlsstart; 4492 dtvsize = dtv[1]; 4493 for (i = 0; i < dtvsize; i++) { 4494 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4495 free((void*)dtv[i+2]); 4496 } 4497 } 4498 free(dtv); 4499 free(tcb); 4500} 4501 4502#endif 4503 4504#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4505 4506/* 4507 * Allocate Static TLS using the Variant II method. 4508 */ 4509void * 4510allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4511{ 4512 Obj_Entry *obj; 4513 size_t size, ralign; 4514 char *tls; 4515 Elf_Addr *dtv, *olddtv; 4516 Elf_Addr segbase, oldsegbase, addr; 4517 int i; 4518 4519 ralign = tcbalign; 4520 if (tls_static_max_align > ralign) 4521 ralign = tls_static_max_align; 4522 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4523 4524 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4525 tls = malloc_aligned(size, ralign); 4526 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4527 4528 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4529 ((Elf_Addr*)segbase)[0] = segbase; 4530 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4531 4532 dtv[0] = tls_dtv_generation; 4533 dtv[1] = tls_max_index; 4534 4535 if (oldtls) { 4536 /* 4537 * Copy the static TLS block over whole. 4538 */ 4539 oldsegbase = (Elf_Addr) oldtls; 4540 memcpy((void *)(segbase - tls_static_space), 4541 (const void *)(oldsegbase - tls_static_space), 4542 tls_static_space); 4543 4544 /* 4545 * If any dynamic TLS blocks have been created tls_get_addr(), 4546 * move them over. 4547 */ 4548 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4549 for (i = 0; i < olddtv[1]; i++) { 4550 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4551 dtv[i+2] = olddtv[i+2]; 4552 olddtv[i+2] = 0; 4553 } 4554 } 4555 4556 /* 4557 * We assume that this block was the one we created with 4558 * allocate_initial_tls(). 4559 */ 4560 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4561 } else { 4562 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4563 if (obj->marker || obj->tlsoffset == 0) 4564 continue; 4565 addr = segbase - obj->tlsoffset; 4566 memset((void*) (addr + obj->tlsinitsize), 4567 0, obj->tlssize - obj->tlsinitsize); 4568 if (obj->tlsinit) 4569 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4570 dtv[obj->tlsindex + 1] = addr; 4571 } 4572 } 4573 4574 return (void*) segbase; 4575} 4576 4577void 4578free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4579{ 4580 Elf_Addr* dtv; 4581 size_t size, ralign; 4582 int dtvsize, i; 4583 Elf_Addr tlsstart, tlsend; 4584 4585 /* 4586 * Figure out the size of the initial TLS block so that we can 4587 * find stuff which ___tls_get_addr() allocated dynamically. 4588 */ 4589 ralign = tcbalign; 4590 if (tls_static_max_align > ralign) 4591 ralign = tls_static_max_align; 4592 size = round(tls_static_space, ralign); 4593 4594 dtv = ((Elf_Addr**)tls)[1]; 4595 dtvsize = dtv[1]; 4596 tlsend = (Elf_Addr) tls; 4597 tlsstart = tlsend - size; 4598 for (i = 0; i < dtvsize; i++) { 4599 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4600 free_aligned((void *)dtv[i + 2]); 4601 } 4602 } 4603 4604 free_aligned((void *)tlsstart); 4605 free((void*) dtv); 4606} 4607 4608#endif 4609 4610/* 4611 * Allocate TLS block for module with given index. 4612 */ 4613void * 4614allocate_module_tls(int index) 4615{ 4616 Obj_Entry* obj; 4617 char* p; 4618 4619 TAILQ_FOREACH(obj, &obj_list, next) { 4620 if (obj->marker) 4621 continue; 4622 if (obj->tlsindex == index) 4623 break; 4624 } 4625 if (!obj) { 4626 _rtld_error("Can't find module with TLS index %d", index); 4627 rtld_die(); 4628 } 4629 4630 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4631 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4632 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4633 4634 return p; 4635} 4636 4637bool 4638allocate_tls_offset(Obj_Entry *obj) 4639{ 4640 size_t off; 4641 4642 if (obj->tls_done) 4643 return true; 4644 4645 if (obj->tlssize == 0) { 4646 obj->tls_done = true; 4647 return true; 4648 } 4649 4650 if (tls_last_offset == 0) 4651 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4652 else 4653 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4654 obj->tlssize, obj->tlsalign); 4655 4656 /* 4657 * If we have already fixed the size of the static TLS block, we 4658 * must stay within that size. When allocating the static TLS, we 4659 * leave a small amount of space spare to be used for dynamically 4660 * loading modules which use static TLS. 4661 */ 4662 if (tls_static_space != 0) { 4663 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4664 return false; 4665 } else if (obj->tlsalign > tls_static_max_align) { 4666 tls_static_max_align = obj->tlsalign; 4667 } 4668 4669 tls_last_offset = obj->tlsoffset = off; 4670 tls_last_size = obj->tlssize; 4671 obj->tls_done = true; 4672 4673 return true; 4674} 4675 4676void 4677free_tls_offset(Obj_Entry *obj) 4678{ 4679 4680 /* 4681 * If we were the last thing to allocate out of the static TLS 4682 * block, we give our space back to the 'allocator'. This is a 4683 * simplistic workaround to allow libGL.so.1 to be loaded and 4684 * unloaded multiple times. 4685 */ 4686 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4687 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4688 tls_last_offset -= obj->tlssize; 4689 tls_last_size = 0; 4690 } 4691} 4692 4693void * 4694_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4695{ 4696 void *ret; 4697 RtldLockState lockstate; 4698 4699 wlock_acquire(rtld_bind_lock, &lockstate); 4700 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4701 tcbsize, tcbalign); 4702 lock_release(rtld_bind_lock, &lockstate); 4703 return (ret); 4704} 4705 4706void 4707_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4708{ 4709 RtldLockState lockstate; 4710 4711 wlock_acquire(rtld_bind_lock, &lockstate); 4712 free_tls(tcb, tcbsize, tcbalign); 4713 lock_release(rtld_bind_lock, &lockstate); 4714} 4715 4716static void 4717object_add_name(Obj_Entry *obj, const char *name) 4718{ 4719 Name_Entry *entry; 4720 size_t len; 4721 4722 len = strlen(name); 4723 entry = malloc(sizeof(Name_Entry) + len); 4724 4725 if (entry != NULL) { 4726 strcpy(entry->name, name); 4727 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4728 } 4729} 4730 4731static int 4732object_match_name(const Obj_Entry *obj, const char *name) 4733{ 4734 Name_Entry *entry; 4735 4736 STAILQ_FOREACH(entry, &obj->names, link) { 4737 if (strcmp(name, entry->name) == 0) 4738 return (1); 4739 } 4740 return (0); 4741} 4742 4743static Obj_Entry * 4744locate_dependency(const Obj_Entry *obj, const char *name) 4745{ 4746 const Objlist_Entry *entry; 4747 const Needed_Entry *needed; 4748 4749 STAILQ_FOREACH(entry, &list_main, link) { 4750 if (object_match_name(entry->obj, name)) 4751 return entry->obj; 4752 } 4753 4754 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4755 if (strcmp(obj->strtab + needed->name, name) == 0 || 4756 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4757 /* 4758 * If there is DT_NEEDED for the name we are looking for, 4759 * we are all set. Note that object might not be found if 4760 * dependency was not loaded yet, so the function can 4761 * return NULL here. This is expected and handled 4762 * properly by the caller. 4763 */ 4764 return (needed->obj); 4765 } 4766 } 4767 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4768 obj->path, name); 4769 rtld_die(); 4770} 4771 4772static int 4773check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4774 const Elf_Vernaux *vna) 4775{ 4776 const Elf_Verdef *vd; 4777 const char *vername; 4778 4779 vername = refobj->strtab + vna->vna_name; 4780 vd = depobj->verdef; 4781 if (vd == NULL) { 4782 _rtld_error("%s: version %s required by %s not defined", 4783 depobj->path, vername, refobj->path); 4784 return (-1); 4785 } 4786 for (;;) { 4787 if (vd->vd_version != VER_DEF_CURRENT) { 4788 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4789 depobj->path, vd->vd_version); 4790 return (-1); 4791 } 4792 if (vna->vna_hash == vd->vd_hash) { 4793 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4794 ((char *)vd + vd->vd_aux); 4795 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4796 return (0); 4797 } 4798 if (vd->vd_next == 0) 4799 break; 4800 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4801 } 4802 if (vna->vna_flags & VER_FLG_WEAK) 4803 return (0); 4804 _rtld_error("%s: version %s required by %s not found", 4805 depobj->path, vername, refobj->path); 4806 return (-1); 4807} 4808 4809static int 4810rtld_verify_object_versions(Obj_Entry *obj) 4811{ 4812 const Elf_Verneed *vn; 4813 const Elf_Verdef *vd; 4814 const Elf_Verdaux *vda; 4815 const Elf_Vernaux *vna; 4816 const Obj_Entry *depobj; 4817 int maxvernum, vernum; 4818 4819 if (obj->ver_checked) 4820 return (0); 4821 obj->ver_checked = true; 4822 4823 maxvernum = 0; 4824 /* 4825 * Walk over defined and required version records and figure out 4826 * max index used by any of them. Do very basic sanity checking 4827 * while there. 4828 */ 4829 vn = obj->verneed; 4830 while (vn != NULL) { 4831 if (vn->vn_version != VER_NEED_CURRENT) { 4832 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4833 obj->path, vn->vn_version); 4834 return (-1); 4835 } 4836 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4837 for (;;) { 4838 vernum = VER_NEED_IDX(vna->vna_other); 4839 if (vernum > maxvernum) 4840 maxvernum = vernum; 4841 if (vna->vna_next == 0) 4842 break; 4843 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4844 } 4845 if (vn->vn_next == 0) 4846 break; 4847 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4848 } 4849 4850 vd = obj->verdef; 4851 while (vd != NULL) { 4852 if (vd->vd_version != VER_DEF_CURRENT) { 4853 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4854 obj->path, vd->vd_version); 4855 return (-1); 4856 } 4857 vernum = VER_DEF_IDX(vd->vd_ndx); 4858 if (vernum > maxvernum) 4859 maxvernum = vernum; 4860 if (vd->vd_next == 0) 4861 break; 4862 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4863 } 4864 4865 if (maxvernum == 0) 4866 return (0); 4867 4868 /* 4869 * Store version information in array indexable by version index. 4870 * Verify that object version requirements are satisfied along the 4871 * way. 4872 */ 4873 obj->vernum = maxvernum + 1; 4874 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4875 4876 vd = obj->verdef; 4877 while (vd != NULL) { 4878 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4879 vernum = VER_DEF_IDX(vd->vd_ndx); 4880 assert(vernum <= maxvernum); 4881 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4882 obj->vertab[vernum].hash = vd->vd_hash; 4883 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4884 obj->vertab[vernum].file = NULL; 4885 obj->vertab[vernum].flags = 0; 4886 } 4887 if (vd->vd_next == 0) 4888 break; 4889 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4890 } 4891 4892 vn = obj->verneed; 4893 while (vn != NULL) { 4894 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4895 if (depobj == NULL) 4896 return (-1); 4897 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4898 for (;;) { 4899 if (check_object_provided_version(obj, depobj, vna)) 4900 return (-1); 4901 vernum = VER_NEED_IDX(vna->vna_other); 4902 assert(vernum <= maxvernum); 4903 obj->vertab[vernum].hash = vna->vna_hash; 4904 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4905 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4906 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4907 VER_INFO_HIDDEN : 0; 4908 if (vna->vna_next == 0) 4909 break; 4910 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4911 } 4912 if (vn->vn_next == 0) 4913 break; 4914 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4915 } 4916 return 0; 4917} 4918 4919static int 4920rtld_verify_versions(const Objlist *objlist) 4921{ 4922 Objlist_Entry *entry; 4923 int rc; 4924 4925 rc = 0; 4926 STAILQ_FOREACH(entry, objlist, link) { 4927 /* 4928 * Skip dummy objects or objects that have their version requirements 4929 * already checked. 4930 */ 4931 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4932 continue; 4933 if (rtld_verify_object_versions(entry->obj) == -1) { 4934 rc = -1; 4935 if (ld_tracing == NULL) 4936 break; 4937 } 4938 } 4939 if (rc == 0 || ld_tracing != NULL) 4940 rc = rtld_verify_object_versions(&obj_rtld); 4941 return rc; 4942} 4943 4944const Ver_Entry * 4945fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4946{ 4947 Elf_Versym vernum; 4948 4949 if (obj->vertab) { 4950 vernum = VER_NDX(obj->versyms[symnum]); 4951 if (vernum >= obj->vernum) { 4952 _rtld_error("%s: symbol %s has wrong verneed value %d", 4953 obj->path, obj->strtab + symnum, vernum); 4954 } else if (obj->vertab[vernum].hash != 0) { 4955 return &obj->vertab[vernum]; 4956 } 4957 } 4958 return NULL; 4959} 4960 4961int 4962_rtld_get_stack_prot(void) 4963{ 4964 4965 return (stack_prot); 4966} 4967 4968int 4969_rtld_is_dlopened(void *arg) 4970{ 4971 Obj_Entry *obj; 4972 RtldLockState lockstate; 4973 int res; 4974 4975 rlock_acquire(rtld_bind_lock, &lockstate); 4976 obj = dlcheck(arg); 4977 if (obj == NULL) 4978 obj = obj_from_addr(arg); 4979 if (obj == NULL) { 4980 _rtld_error("No shared object contains address"); 4981 lock_release(rtld_bind_lock, &lockstate); 4982 return (-1); 4983 } 4984 res = obj->dlopened ? 1 : 0; 4985 lock_release(rtld_bind_lock, &lockstate); 4986 return (res); 4987} 4988 4989static void 4990map_stacks_exec(RtldLockState *lockstate) 4991{ 4992 void (*thr_map_stacks_exec)(void); 4993 4994 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4995 return; 4996 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4997 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4998 if (thr_map_stacks_exec != NULL) { 4999 stack_prot |= PROT_EXEC; 5000 thr_map_stacks_exec(); 5001 } 5002} 5003 5004void 5005symlook_init(SymLook *dst, const char *name) 5006{ 5007 5008 bzero(dst, sizeof(*dst)); 5009 dst->name = name; 5010 dst->hash = elf_hash(name); 5011 dst->hash_gnu = gnu_hash(name); 5012} 5013 5014static void 5015symlook_init_from_req(SymLook *dst, const SymLook *src) 5016{ 5017 5018 dst->name = src->name; 5019 dst->hash = src->hash; 5020 dst->hash_gnu = src->hash_gnu; 5021 dst->ventry = src->ventry; 5022 dst->flags = src->flags; 5023 dst->defobj_out = NULL; 5024 dst->sym_out = NULL; 5025 dst->lockstate = src->lockstate; 5026} 5027 5028/* 5029 * Overrides for libc_pic-provided functions. 5030 */ 5031 5032int 5033__getosreldate(void) 5034{ 5035 size_t len; 5036 int oid[2]; 5037 int error, osrel; 5038 5039 if (osreldate != 0) 5040 return (osreldate); 5041 5042 oid[0] = CTL_KERN; 5043 oid[1] = KERN_OSRELDATE; 5044 osrel = 0; 5045 len = sizeof(osrel); 5046 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5047 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5048 osreldate = osrel; 5049 return (osreldate); 5050} 5051 5052void 5053exit(int status) 5054{ 5055 5056 _exit(status); 5057} 5058 5059void (*__cleanup)(void); 5060int __isthreaded = 0; 5061int _thread_autoinit_dummy_decl = 1; 5062 5063/* 5064 * No unresolved symbols for rtld. 5065 */ 5066void 5067__pthread_cxa_finalize(struct dl_phdr_info *a) 5068{ 5069} 5070 5071void 5072__stack_chk_fail(void) 5073{ 5074 5075 _rtld_error("stack overflow detected; terminated"); 5076 rtld_die(); 5077} 5078__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5079 5080void 5081__chk_fail(void) 5082{ 5083 5084 _rtld_error("buffer overflow detected; terminated"); 5085 rtld_die(); 5086} 5087 5088const char * 5089rtld_strerror(int errnum) 5090{ 5091 5092 if (errnum < 0 || errnum >= sys_nerr) 5093 return ("Unknown error"); 5094 return (sys_errlist[errnum]); 5095} 5096