rtld.c revision 284954
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 284954 2015-06-30 14:17:02Z des $ 29 */ 30 31/* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37#ifndef __GNUC__ 38#error "GCC is needed to compile this file" 39#endif 40 41#include <sys/param.h> 42#include <sys/mount.h> 43#include <sys/mman.h> 44#include <sys/stat.h> 45#include <sys/sysctl.h> 46#include <sys/uio.h> 47#include <sys/utsname.h> 48#include <sys/ktrace.h> 49 50#include <dlfcn.h> 51#include <err.h> 52#include <errno.h> 53#include <fcntl.h> 54#include <stdarg.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#include <unistd.h> 59 60#include "debug.h" 61#include "rtld.h" 62#include "libmap.h" 63#include "rtld_tls.h" 64#include "rtld_printf.h" 65#include "notes.h" 66 67#ifndef COMPAT_32BIT 68#define PATH_RTLD "/libexec/ld-elf.so.1" 69#else 70#define PATH_RTLD "/libexec/ld-elf32.so.1" 71#endif 72 73/* Types. */ 74typedef void (*func_ptr_type)(); 75typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77/* 78 * Function declarations. 79 */ 80static const char *basename(const char *); 81static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **, const Elf_Dyn **); 83static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 84 const Elf_Dyn *); 85static void digest_dynamic(Obj_Entry *, int); 86static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 87static Obj_Entry *dlcheck(void *); 88static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92static bool donelist_check(DoneList *, const Obj_Entry *); 93static void errmsg_restore(char *); 94static char *errmsg_save(void); 95static void *fill_search_info(const char *, size_t, void *); 96static char *find_library(const char *, const Obj_Entry *); 97static const char *gethints(bool); 98static void init_dag(Obj_Entry *); 99static void init_pagesizes(Elf_Auxinfo **aux_info); 100static void init_rtld(caddr_t, Elf_Auxinfo **); 101static void initlist_add_neededs(Needed_Entry *, Objlist *); 102static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103static void linkmap_add(Obj_Entry *); 104static void linkmap_delete(Obj_Entry *); 105static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106static void unload_filtees(Obj_Entry *); 107static int load_needed_objects(Obj_Entry *, int); 108static int load_preload_objects(void); 109static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110static void map_stacks_exec(RtldLockState *); 111static Obj_Entry *obj_from_addr(const void *); 112static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113static void objlist_call_init(Objlist *, RtldLockState *); 114static void objlist_clear(Objlist *); 115static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116static void objlist_init(Objlist *); 117static void objlist_push_head(Objlist *, Obj_Entry *); 118static void objlist_push_tail(Objlist *, Obj_Entry *); 119static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120static void objlist_remove(Objlist *, Obj_Entry *); 121static void *path_enumerate(const char *, path_enum_proc, void *); 122static int relocate_object_dag(Obj_Entry *root, bool bind_now, 123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 124static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 125 int flags, RtldLockState *lockstate); 126static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 127 RtldLockState *); 128static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 129 int flags, RtldLockState *lockstate); 130static int rtld_dirname(const char *, char *); 131static int rtld_dirname_abs(const char *, char *); 132static void *rtld_dlopen(const char *name, int fd, int mode); 133static void rtld_exit(void); 134static char *search_library_path(const char *, const char *); 135static const void **get_program_var_addr(const char *, RtldLockState *); 136static void set_program_var(const char *, const void *); 137static int symlook_default(SymLook *, const Obj_Entry *refobj); 138static int symlook_global(SymLook *, DoneList *); 139static void symlook_init_from_req(SymLook *, const SymLook *); 140static int symlook_list(SymLook *, const Objlist *, DoneList *); 141static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 142static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 143static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 144static void trace_loaded_objects(Obj_Entry *); 145static void unlink_object(Obj_Entry *); 146static void unload_object(Obj_Entry *); 147static void unref_dag(Obj_Entry *); 148static void ref_dag(Obj_Entry *); 149static char *origin_subst_one(Obj_Entry *, char *, const char *, 150 const char *, bool); 151static char *origin_subst(Obj_Entry *, char *); 152static bool obj_resolve_origin(Obj_Entry *obj); 153static void preinit_main(void); 154static int rtld_verify_versions(const Objlist *); 155static int rtld_verify_object_versions(Obj_Entry *); 156static void object_add_name(Obj_Entry *, const char *); 157static int object_match_name(const Obj_Entry *, const char *); 158static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 159static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 160 struct dl_phdr_info *phdr_info); 161static uint32_t gnu_hash(const char *); 162static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 163 const unsigned long); 164 165void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 166void _r_debug_postinit(struct link_map *) __noinline __exported; 167 168/* 169 * Data declarations. 170 */ 171static char *error_message; /* Message for dlerror(), or NULL */ 172struct r_debug r_debug __exported; /* for GDB; */ 173static bool libmap_disable; /* Disable libmap */ 174static bool ld_loadfltr; /* Immediate filters processing */ 175static char *libmap_override; /* Maps to use in addition to libmap.conf */ 176static bool trust; /* False for setuid and setgid programs */ 177static bool dangerous_ld_env; /* True if environment variables have been 178 used to affect the libraries loaded */ 179static char *ld_bind_now; /* Environment variable for immediate binding */ 180static char *ld_debug; /* Environment variable for debugging */ 181static char *ld_library_path; /* Environment variable for search path */ 182static char *ld_preload; /* Environment variable for libraries to 183 load first */ 184static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 185static char *ld_tracing; /* Called from ldd to print libs */ 186static char *ld_utrace; /* Use utrace() to log events. */ 187static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 188static Obj_Entry **obj_tail; /* Link field of last object in list */ 189static Obj_Entry *obj_main; /* The main program shared object */ 190static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 191static unsigned int obj_count; /* Number of objects in obj_list */ 192static unsigned int obj_loads; /* Number of objects in obj_list */ 193 194static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 195 STAILQ_HEAD_INITIALIZER(list_global); 196static Objlist list_main = /* Objects loaded at program startup */ 197 STAILQ_HEAD_INITIALIZER(list_main); 198static Objlist list_fini = /* Objects needing fini() calls */ 199 STAILQ_HEAD_INITIALIZER(list_fini); 200 201Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 202 203#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 204 205extern Elf_Dyn _DYNAMIC; 206#pragma weak _DYNAMIC 207#ifndef RTLD_IS_DYNAMIC 208#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 209#endif 210 211int dlclose(void *) __exported; 212char *dlerror(void) __exported; 213void *dlopen(const char *, int) __exported; 214void *fdlopen(int, int) __exported; 215void *dlsym(void *, const char *) __exported; 216dlfunc_t dlfunc(void *, const char *) __exported; 217void *dlvsym(void *, const char *, const char *) __exported; 218int dladdr(const void *, Dl_info *) __exported; 219void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 220 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 221int dlinfo(void *, int , void *) __exported; 222int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 223int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 224int _rtld_get_stack_prot(void) __exported; 225int _rtld_is_dlopened(void *) __exported; 226void _rtld_error(const char *, ...) __exported; 227 228int npagesizes, osreldate; 229size_t *pagesizes; 230 231long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 232 233static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 234static int max_stack_flags; 235 236/* 237 * Global declarations normally provided by crt1. The dynamic linker is 238 * not built with crt1, so we have to provide them ourselves. 239 */ 240char *__progname; 241char **environ; 242 243/* 244 * Used to pass argc, argv to init functions. 245 */ 246int main_argc; 247char **main_argv; 248 249/* 250 * Globals to control TLS allocation. 251 */ 252size_t tls_last_offset; /* Static TLS offset of last module */ 253size_t tls_last_size; /* Static TLS size of last module */ 254size_t tls_static_space; /* Static TLS space allocated */ 255size_t tls_static_max_align; 256int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 257int tls_max_index = 1; /* Largest module index allocated */ 258 259bool ld_library_path_rpath = false; 260 261/* 262 * Fill in a DoneList with an allocation large enough to hold all of 263 * the currently-loaded objects. Keep this as a macro since it calls 264 * alloca and we want that to occur within the scope of the caller. 265 */ 266#define donelist_init(dlp) \ 267 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 268 assert((dlp)->objs != NULL), \ 269 (dlp)->num_alloc = obj_count, \ 270 (dlp)->num_used = 0) 271 272#define UTRACE_DLOPEN_START 1 273#define UTRACE_DLOPEN_STOP 2 274#define UTRACE_DLCLOSE_START 3 275#define UTRACE_DLCLOSE_STOP 4 276#define UTRACE_LOAD_OBJECT 5 277#define UTRACE_UNLOAD_OBJECT 6 278#define UTRACE_ADD_RUNDEP 7 279#define UTRACE_PRELOAD_FINISHED 8 280#define UTRACE_INIT_CALL 9 281#define UTRACE_FINI_CALL 10 282#define UTRACE_DLSYM_START 11 283#define UTRACE_DLSYM_STOP 12 284 285struct utrace_rtld { 286 char sig[4]; /* 'RTLD' */ 287 int event; 288 void *handle; 289 void *mapbase; /* Used for 'parent' and 'init/fini' */ 290 size_t mapsize; 291 int refcnt; /* Used for 'mode' */ 292 char name[MAXPATHLEN]; 293}; 294 295#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 296 if (ld_utrace != NULL) \ 297 ld_utrace_log(e, h, mb, ms, r, n); \ 298} while (0) 299 300static void 301ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 302 int refcnt, const char *name) 303{ 304 struct utrace_rtld ut; 305 306 ut.sig[0] = 'R'; 307 ut.sig[1] = 'T'; 308 ut.sig[2] = 'L'; 309 ut.sig[3] = 'D'; 310 ut.event = event; 311 ut.handle = handle; 312 ut.mapbase = mapbase; 313 ut.mapsize = mapsize; 314 ut.refcnt = refcnt; 315 bzero(ut.name, sizeof(ut.name)); 316 if (name) 317 strlcpy(ut.name, name, sizeof(ut.name)); 318 utrace(&ut, sizeof(ut)); 319} 320 321/* 322 * Main entry point for dynamic linking. The first argument is the 323 * stack pointer. The stack is expected to be laid out as described 324 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 325 * Specifically, the stack pointer points to a word containing 326 * ARGC. Following that in the stack is a null-terminated sequence 327 * of pointers to argument strings. Then comes a null-terminated 328 * sequence of pointers to environment strings. Finally, there is a 329 * sequence of "auxiliary vector" entries. 330 * 331 * The second argument points to a place to store the dynamic linker's 332 * exit procedure pointer and the third to a place to store the main 333 * program's object. 334 * 335 * The return value is the main program's entry point. 336 */ 337func_ptr_type 338_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 339{ 340 Elf_Auxinfo *aux_info[AT_COUNT]; 341 int i; 342 int argc; 343 char **argv; 344 char **env; 345 Elf_Auxinfo *aux; 346 Elf_Auxinfo *auxp; 347 const char *argv0; 348 Objlist_Entry *entry; 349 Obj_Entry *obj; 350 Obj_Entry **preload_tail; 351 Obj_Entry *last_interposer; 352 Objlist initlist; 353 RtldLockState lockstate; 354 char *library_path_rpath; 355 int mib[2]; 356 size_t len; 357 358 /* 359 * On entry, the dynamic linker itself has not been relocated yet. 360 * Be very careful not to reference any global data until after 361 * init_rtld has returned. It is OK to reference file-scope statics 362 * and string constants, and to call static and global functions. 363 */ 364 365 /* Find the auxiliary vector on the stack. */ 366 argc = *sp++; 367 argv = (char **) sp; 368 sp += argc + 1; /* Skip over arguments and NULL terminator */ 369 env = (char **) sp; 370 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 371 ; 372 aux = (Elf_Auxinfo *) sp; 373 374 /* Digest the auxiliary vector. */ 375 for (i = 0; i < AT_COUNT; i++) 376 aux_info[i] = NULL; 377 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 378 if (auxp->a_type < AT_COUNT) 379 aux_info[auxp->a_type] = auxp; 380 } 381 382 /* Initialize and relocate ourselves. */ 383 assert(aux_info[AT_BASE] != NULL); 384 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 385 386 __progname = obj_rtld.path; 387 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 388 environ = env; 389 main_argc = argc; 390 main_argv = argv; 391 392 if (aux_info[AT_CANARY] != NULL && 393 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 394 i = aux_info[AT_CANARYLEN]->a_un.a_val; 395 if (i > sizeof(__stack_chk_guard)) 396 i = sizeof(__stack_chk_guard); 397 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 398 } else { 399 mib[0] = CTL_KERN; 400 mib[1] = KERN_ARND; 401 402 len = sizeof(__stack_chk_guard); 403 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 404 len != sizeof(__stack_chk_guard)) { 405 /* If sysctl was unsuccessful, use the "terminator canary". */ 406 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 407 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 408 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 409 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 410 } 411 } 412 413 trust = !issetugid(); 414 415 ld_bind_now = getenv(LD_ "BIND_NOW"); 416 /* 417 * If the process is tainted, then we un-set the dangerous environment 418 * variables. The process will be marked as tainted until setuid(2) 419 * is called. If any child process calls setuid(2) we do not want any 420 * future processes to honor the potentially un-safe variables. 421 */ 422 if (!trust) { 423 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 424 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 425 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 426 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 427 _rtld_error("environment corrupt; aborting"); 428 rtld_die(); 429 } 430 } 431 ld_debug = getenv(LD_ "DEBUG"); 432 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 433 libmap_override = getenv(LD_ "LIBMAP"); 434 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 435 ld_preload = getenv(LD_ "PRELOAD"); 436 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 437 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 438 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 439 if (library_path_rpath != NULL) { 440 if (library_path_rpath[0] == 'y' || 441 library_path_rpath[0] == 'Y' || 442 library_path_rpath[0] == '1') 443 ld_library_path_rpath = true; 444 else 445 ld_library_path_rpath = false; 446 } 447 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 448 (ld_library_path != NULL) || (ld_preload != NULL) || 449 (ld_elf_hints_path != NULL) || ld_loadfltr; 450 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 451 ld_utrace = getenv(LD_ "UTRACE"); 452 453 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 454 ld_elf_hints_path = _PATH_ELF_HINTS; 455 456 if (ld_debug != NULL && *ld_debug != '\0') 457 debug = 1; 458 dbg("%s is initialized, base address = %p", __progname, 459 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 460 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 461 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 462 463 dbg("initializing thread locks"); 464 lockdflt_init(); 465 466 /* 467 * Load the main program, or process its program header if it is 468 * already loaded. 469 */ 470 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 471 int fd = aux_info[AT_EXECFD]->a_un.a_val; 472 dbg("loading main program"); 473 obj_main = map_object(fd, argv0, NULL); 474 close(fd); 475 if (obj_main == NULL) 476 rtld_die(); 477 max_stack_flags = obj->stack_flags; 478 } else { /* Main program already loaded. */ 479 const Elf_Phdr *phdr; 480 int phnum; 481 caddr_t entry; 482 483 dbg("processing main program's program header"); 484 assert(aux_info[AT_PHDR] != NULL); 485 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 486 assert(aux_info[AT_PHNUM] != NULL); 487 phnum = aux_info[AT_PHNUM]->a_un.a_val; 488 assert(aux_info[AT_PHENT] != NULL); 489 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 490 assert(aux_info[AT_ENTRY] != NULL); 491 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 492 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 493 rtld_die(); 494 } 495 496 if (aux_info[AT_EXECPATH] != 0) { 497 char *kexecpath; 498 char buf[MAXPATHLEN]; 499 500 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 501 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 502 if (kexecpath[0] == '/') 503 obj_main->path = kexecpath; 504 else if (getcwd(buf, sizeof(buf)) == NULL || 505 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 506 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 507 obj_main->path = xstrdup(argv0); 508 else 509 obj_main->path = xstrdup(buf); 510 } else { 511 dbg("No AT_EXECPATH"); 512 obj_main->path = xstrdup(argv0); 513 } 514 dbg("obj_main path %s", obj_main->path); 515 obj_main->mainprog = true; 516 517 if (aux_info[AT_STACKPROT] != NULL && 518 aux_info[AT_STACKPROT]->a_un.a_val != 0) 519 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 520 521#ifndef COMPAT_32BIT 522 /* 523 * Get the actual dynamic linker pathname from the executable if 524 * possible. (It should always be possible.) That ensures that 525 * gdb will find the right dynamic linker even if a non-standard 526 * one is being used. 527 */ 528 if (obj_main->interp != NULL && 529 strcmp(obj_main->interp, obj_rtld.path) != 0) { 530 free(obj_rtld.path); 531 obj_rtld.path = xstrdup(obj_main->interp); 532 __progname = obj_rtld.path; 533 } 534#endif 535 536 digest_dynamic(obj_main, 0); 537 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 538 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 539 obj_main->dynsymcount); 540 541 linkmap_add(obj_main); 542 linkmap_add(&obj_rtld); 543 544 /* Link the main program into the list of objects. */ 545 *obj_tail = obj_main; 546 obj_tail = &obj_main->next; 547 obj_count++; 548 obj_loads++; 549 550 /* Initialize a fake symbol for resolving undefined weak references. */ 551 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 552 sym_zero.st_shndx = SHN_UNDEF; 553 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 554 555 if (!libmap_disable) 556 libmap_disable = (bool)lm_init(libmap_override); 557 558 dbg("loading LD_PRELOAD libraries"); 559 if (load_preload_objects() == -1) 560 rtld_die(); 561 preload_tail = obj_tail; 562 563 dbg("loading needed objects"); 564 if (load_needed_objects(obj_main, 0) == -1) 565 rtld_die(); 566 567 /* Make a list of all objects loaded at startup. */ 568 last_interposer = obj_main; 569 for (obj = obj_list; obj != NULL; obj = obj->next) { 570 if (obj->z_interpose && obj != obj_main) { 571 objlist_put_after(&list_main, last_interposer, obj); 572 last_interposer = obj; 573 } else { 574 objlist_push_tail(&list_main, obj); 575 } 576 obj->refcount++; 577 } 578 579 dbg("checking for required versions"); 580 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 581 rtld_die(); 582 583 if (ld_tracing) { /* We're done */ 584 trace_loaded_objects(obj_main); 585 exit(0); 586 } 587 588 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 589 dump_relocations(obj_main); 590 exit (0); 591 } 592 593 /* 594 * Processing tls relocations requires having the tls offsets 595 * initialized. Prepare offsets before starting initial 596 * relocation processing. 597 */ 598 dbg("initializing initial thread local storage offsets"); 599 STAILQ_FOREACH(entry, &list_main, link) { 600 /* 601 * Allocate all the initial objects out of the static TLS 602 * block even if they didn't ask for it. 603 */ 604 allocate_tls_offset(entry->obj); 605 } 606 607 if (relocate_objects(obj_main, 608 ld_bind_now != NULL && *ld_bind_now != '\0', 609 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 610 rtld_die(); 611 612 dbg("doing copy relocations"); 613 if (do_copy_relocations(obj_main) == -1) 614 rtld_die(); 615 616 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 617 dump_relocations(obj_main); 618 exit (0); 619 } 620 621 /* 622 * Setup TLS for main thread. This must be done after the 623 * relocations are processed, since tls initialization section 624 * might be the subject for relocations. 625 */ 626 dbg("initializing initial thread local storage"); 627 allocate_initial_tls(obj_list); 628 629 dbg("initializing key program variables"); 630 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 631 set_program_var("environ", env); 632 set_program_var("__elf_aux_vector", aux); 633 634 /* Make a list of init functions to call. */ 635 objlist_init(&initlist); 636 initlist_add_objects(obj_list, preload_tail, &initlist); 637 638 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 639 640 map_stacks_exec(NULL); 641 642 dbg("resolving ifuncs"); 643 if (resolve_objects_ifunc(obj_main, 644 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 645 NULL) == -1) 646 rtld_die(); 647 648 if (!obj_main->crt_no_init) { 649 /* 650 * Make sure we don't call the main program's init and fini 651 * functions for binaries linked with old crt1 which calls 652 * _init itself. 653 */ 654 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 655 obj_main->preinit_array = obj_main->init_array = 656 obj_main->fini_array = (Elf_Addr)NULL; 657 } 658 659 wlock_acquire(rtld_bind_lock, &lockstate); 660 if (obj_main->crt_no_init) 661 preinit_main(); 662 objlist_call_init(&initlist, &lockstate); 663 _r_debug_postinit(&obj_main->linkmap); 664 objlist_clear(&initlist); 665 dbg("loading filtees"); 666 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 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 = ((Elf_Addr (*)(void))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, true, NULL, 711 &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 /* XXX - not implemented yet */ 1123 if (!early) 1124 dbg("Filling in DT_DEBUG entry"); 1125 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1126 break; 1127#endif 1128 1129 case DT_FLAGS: 1130 if (dynp->d_un.d_val & DF_ORIGIN) 1131 obj->z_origin = true; 1132 if (dynp->d_un.d_val & DF_SYMBOLIC) 1133 obj->symbolic = true; 1134 if (dynp->d_un.d_val & DF_TEXTREL) 1135 obj->textrel = true; 1136 if (dynp->d_un.d_val & DF_BIND_NOW) 1137 obj->bind_now = true; 1138 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1139 ;*/ 1140 break; 1141#ifdef __mips__ 1142 case DT_MIPS_LOCAL_GOTNO: 1143 obj->local_gotno = dynp->d_un.d_val; 1144 break; 1145 1146 case DT_MIPS_SYMTABNO: 1147 obj->symtabno = dynp->d_un.d_val; 1148 break; 1149 1150 case DT_MIPS_GOTSYM: 1151 obj->gotsym = dynp->d_un.d_val; 1152 break; 1153 1154 case DT_MIPS_RLD_MAP: 1155 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1156 break; 1157#endif 1158 1159 case DT_FLAGS_1: 1160 if (dynp->d_un.d_val & DF_1_NOOPEN) 1161 obj->z_noopen = true; 1162 if (dynp->d_un.d_val & DF_1_ORIGIN) 1163 obj->z_origin = true; 1164 if (dynp->d_un.d_val & DF_1_GLOBAL) 1165 obj->z_global = true; 1166 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1167 obj->bind_now = true; 1168 if (dynp->d_un.d_val & DF_1_NODELETE) 1169 obj->z_nodelete = true; 1170 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1171 obj->z_loadfltr = true; 1172 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1173 obj->z_interpose = true; 1174 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1175 obj->z_nodeflib = true; 1176 break; 1177 1178 default: 1179 if (!early) { 1180 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1181 (long)dynp->d_tag); 1182 } 1183 break; 1184 } 1185 } 1186 1187 obj->traced = false; 1188 1189 if (plttype == DT_RELA) { 1190 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1191 obj->pltrel = NULL; 1192 obj->pltrelasize = obj->pltrelsize; 1193 obj->pltrelsize = 0; 1194 } 1195 1196 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1197 if (obj->valid_hash_sysv) 1198 obj->dynsymcount = obj->nchains; 1199 else if (obj->valid_hash_gnu) { 1200 obj->dynsymcount = 0; 1201 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1202 if (obj->buckets_gnu[bkt] == 0) 1203 continue; 1204 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1205 do 1206 obj->dynsymcount++; 1207 while ((*hashval++ & 1u) == 0); 1208 } 1209 obj->dynsymcount += obj->symndx_gnu; 1210 } 1211} 1212 1213static bool 1214obj_resolve_origin(Obj_Entry *obj) 1215{ 1216 1217 if (obj->origin_path != NULL) 1218 return (true); 1219 obj->origin_path = xmalloc(PATH_MAX); 1220 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1221} 1222 1223static void 1224digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1225 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1226{ 1227 1228 if (obj->z_origin && !obj_resolve_origin(obj)) 1229 rtld_die(); 1230 1231 if (dyn_runpath != NULL) { 1232 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1233 obj->runpath = origin_subst(obj, obj->runpath); 1234 } else if (dyn_rpath != NULL) { 1235 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1236 obj->rpath = origin_subst(obj, obj->rpath); 1237 } 1238 if (dyn_soname != NULL) 1239 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1240} 1241 1242static void 1243digest_dynamic(Obj_Entry *obj, int early) 1244{ 1245 const Elf_Dyn *dyn_rpath; 1246 const Elf_Dyn *dyn_soname; 1247 const Elf_Dyn *dyn_runpath; 1248 1249 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1250 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1251} 1252 1253/* 1254 * Process a shared object's program header. This is used only for the 1255 * main program, when the kernel has already loaded the main program 1256 * into memory before calling the dynamic linker. It creates and 1257 * returns an Obj_Entry structure. 1258 */ 1259static Obj_Entry * 1260digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1261{ 1262 Obj_Entry *obj; 1263 const Elf_Phdr *phlimit = phdr + phnum; 1264 const Elf_Phdr *ph; 1265 Elf_Addr note_start, note_end; 1266 int nsegs = 0; 1267 1268 obj = obj_new(); 1269 for (ph = phdr; ph < phlimit; ph++) { 1270 if (ph->p_type != PT_PHDR) 1271 continue; 1272 1273 obj->phdr = phdr; 1274 obj->phsize = ph->p_memsz; 1275 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1276 break; 1277 } 1278 1279 obj->stack_flags = PF_X | PF_R | PF_W; 1280 1281 for (ph = phdr; ph < phlimit; ph++) { 1282 switch (ph->p_type) { 1283 1284 case PT_INTERP: 1285 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1286 break; 1287 1288 case PT_LOAD: 1289 if (nsegs == 0) { /* First load segment */ 1290 obj->vaddrbase = trunc_page(ph->p_vaddr); 1291 obj->mapbase = obj->vaddrbase + obj->relocbase; 1292 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1293 obj->vaddrbase; 1294 } else { /* Last load segment */ 1295 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1296 obj->vaddrbase; 1297 } 1298 nsegs++; 1299 break; 1300 1301 case PT_DYNAMIC: 1302 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1303 break; 1304 1305 case PT_TLS: 1306 obj->tlsindex = 1; 1307 obj->tlssize = ph->p_memsz; 1308 obj->tlsalign = ph->p_align; 1309 obj->tlsinitsize = ph->p_filesz; 1310 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1311 break; 1312 1313 case PT_GNU_STACK: 1314 obj->stack_flags = ph->p_flags; 1315 break; 1316 1317 case PT_GNU_RELRO: 1318 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1319 obj->relro_size = round_page(ph->p_memsz); 1320 break; 1321 1322 case PT_NOTE: 1323 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1324 note_end = note_start + ph->p_filesz; 1325 digest_notes(obj, note_start, note_end); 1326 break; 1327 } 1328 } 1329 if (nsegs < 1) { 1330 _rtld_error("%s: too few PT_LOAD segments", path); 1331 return NULL; 1332 } 1333 1334 obj->entry = entry; 1335 return obj; 1336} 1337 1338void 1339digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1340{ 1341 const Elf_Note *note; 1342 const char *note_name; 1343 uintptr_t p; 1344 1345 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1346 note = (const Elf_Note *)((const char *)(note + 1) + 1347 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1348 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1349 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1350 note->n_descsz != sizeof(int32_t)) 1351 continue; 1352 if (note->n_type != ABI_NOTETYPE && 1353 note->n_type != CRT_NOINIT_NOTETYPE) 1354 continue; 1355 note_name = (const char *)(note + 1); 1356 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1357 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1358 continue; 1359 switch (note->n_type) { 1360 case ABI_NOTETYPE: 1361 /* FreeBSD osrel note */ 1362 p = (uintptr_t)(note + 1); 1363 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1364 obj->osrel = *(const int32_t *)(p); 1365 dbg("note osrel %d", obj->osrel); 1366 break; 1367 case CRT_NOINIT_NOTETYPE: 1368 /* FreeBSD 'crt does not call init' note */ 1369 obj->crt_no_init = true; 1370 dbg("note crt_no_init"); 1371 break; 1372 } 1373 } 1374} 1375 1376static Obj_Entry * 1377dlcheck(void *handle) 1378{ 1379 Obj_Entry *obj; 1380 1381 for (obj = obj_list; obj != NULL; obj = obj->next) 1382 if (obj == (Obj_Entry *) handle) 1383 break; 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 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 unsigned int SLPndx, hintndx, fndx, fcount; 1633 int fd; 1634 size_t flen; 1635 bool skip; 1636 1637 /* First call, read the hints file */ 1638 if (hints == NULL) { 1639 /* Keep from trying again in case the hints file is bad. */ 1640 hints = ""; 1641 1642 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1643 return (NULL); 1644 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1645 hdr.magic != ELFHINTS_MAGIC || 1646 hdr.version != 1) { 1647 close(fd); 1648 return (NULL); 1649 } 1650 p = xmalloc(hdr.dirlistlen + 1); 1651 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1652 read(fd, p, hdr.dirlistlen + 1) != 1653 (ssize_t)hdr.dirlistlen + 1) { 1654 free(p); 1655 close(fd); 1656 return (NULL); 1657 } 1658 hints = p; 1659 close(fd); 1660 } 1661 1662 /* 1663 * If caller agreed to receive list which includes the default 1664 * paths, we are done. Otherwise, if we still did not 1665 * calculated filtered result, do it now. 1666 */ 1667 if (!nostdlib) 1668 return (hints[0] != '\0' ? hints : NULL); 1669 if (filtered_path != NULL) 1670 goto filt_ret; 1671 1672 /* 1673 * Obtain the list of all configured search paths, and the 1674 * list of the default paths. 1675 * 1676 * First estimate the size of the results. 1677 */ 1678 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1679 smeta.dls_cnt = 0; 1680 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1681 hmeta.dls_cnt = 0; 1682 1683 sargs.request = RTLD_DI_SERINFOSIZE; 1684 sargs.serinfo = &smeta; 1685 hargs.request = RTLD_DI_SERINFOSIZE; 1686 hargs.serinfo = &hmeta; 1687 1688 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1689 path_enumerate(p, fill_search_info, &hargs); 1690 1691 SLPinfo = xmalloc(smeta.dls_size); 1692 hintinfo = xmalloc(hmeta.dls_size); 1693 1694 /* 1695 * Next fetch both sets of paths. 1696 */ 1697 sargs.request = RTLD_DI_SERINFO; 1698 sargs.serinfo = SLPinfo; 1699 sargs.serpath = &SLPinfo->dls_serpath[0]; 1700 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1701 1702 hargs.request = RTLD_DI_SERINFO; 1703 hargs.serinfo = hintinfo; 1704 hargs.serpath = &hintinfo->dls_serpath[0]; 1705 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1706 1707 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1708 path_enumerate(p, fill_search_info, &hargs); 1709 1710 /* 1711 * Now calculate the difference between two sets, by excluding 1712 * standard paths from the full set. 1713 */ 1714 fndx = 0; 1715 fcount = 0; 1716 filtered_path = xmalloc(hdr.dirlistlen + 1); 1717 hintpath = &hintinfo->dls_serpath[0]; 1718 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1719 skip = false; 1720 SLPpath = &SLPinfo->dls_serpath[0]; 1721 /* 1722 * Check each standard path against current. 1723 */ 1724 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1725 /* matched, skip the path */ 1726 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1727 skip = true; 1728 break; 1729 } 1730 } 1731 if (skip) 1732 continue; 1733 /* 1734 * Not matched against any standard path, add the path 1735 * to result. Separate consequtive paths with ':'. 1736 */ 1737 if (fcount > 0) { 1738 filtered_path[fndx] = ':'; 1739 fndx++; 1740 } 1741 fcount++; 1742 flen = strlen(hintpath->dls_name); 1743 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1744 fndx += flen; 1745 } 1746 filtered_path[fndx] = '\0'; 1747 1748 free(SLPinfo); 1749 free(hintinfo); 1750 1751filt_ret: 1752 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1753} 1754 1755static void 1756init_dag(Obj_Entry *root) 1757{ 1758 const Needed_Entry *needed; 1759 const Objlist_Entry *elm; 1760 DoneList donelist; 1761 1762 if (root->dag_inited) 1763 return; 1764 donelist_init(&donelist); 1765 1766 /* Root object belongs to own DAG. */ 1767 objlist_push_tail(&root->dldags, root); 1768 objlist_push_tail(&root->dagmembers, root); 1769 donelist_check(&donelist, root); 1770 1771 /* 1772 * Add dependencies of root object to DAG in breadth order 1773 * by exploiting the fact that each new object get added 1774 * to the tail of the dagmembers list. 1775 */ 1776 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1777 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1778 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1779 continue; 1780 objlist_push_tail(&needed->obj->dldags, root); 1781 objlist_push_tail(&root->dagmembers, needed->obj); 1782 } 1783 } 1784 root->dag_inited = true; 1785} 1786 1787static void 1788process_z(Obj_Entry *root) 1789{ 1790 const Objlist_Entry *elm; 1791 Obj_Entry *obj; 1792 1793 /* 1794 * Walk over object DAG and process every dependent object 1795 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1796 * to grow their own DAG. 1797 * 1798 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1799 * symlook_global() to work. 1800 * 1801 * For DF_1_NODELETE, the DAG should have its reference upped. 1802 */ 1803 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1804 obj = elm->obj; 1805 if (obj == NULL) 1806 continue; 1807 if (obj->z_nodelete && !obj->ref_nodel) { 1808 dbg("obj %s -z nodelete", obj->path); 1809 init_dag(obj); 1810 ref_dag(obj); 1811 obj->ref_nodel = true; 1812 } 1813 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1814 dbg("obj %s -z global", obj->path); 1815 objlist_push_tail(&list_global, obj); 1816 init_dag(obj); 1817 } 1818 } 1819} 1820/* 1821 * Initialize the dynamic linker. The argument is the address at which 1822 * the dynamic linker has been mapped into memory. The primary task of 1823 * this function is to relocate the dynamic linker. 1824 */ 1825static void 1826init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1827{ 1828 Obj_Entry objtmp; /* Temporary rtld object */ 1829 const Elf_Dyn *dyn_rpath; 1830 const Elf_Dyn *dyn_soname; 1831 const Elf_Dyn *dyn_runpath; 1832 1833#ifdef RTLD_INIT_PAGESIZES_EARLY 1834 /* The page size is required by the dynamic memory allocator. */ 1835 init_pagesizes(aux_info); 1836#endif 1837 1838 /* 1839 * Conjure up an Obj_Entry structure for the dynamic linker. 1840 * 1841 * The "path" member can't be initialized yet because string constants 1842 * cannot yet be accessed. Below we will set it correctly. 1843 */ 1844 memset(&objtmp, 0, sizeof(objtmp)); 1845 objtmp.path = NULL; 1846 objtmp.rtld = true; 1847 objtmp.mapbase = mapbase; 1848#ifdef PIC 1849 objtmp.relocbase = mapbase; 1850#endif 1851 if (RTLD_IS_DYNAMIC()) { 1852 objtmp.dynamic = rtld_dynamic(&objtmp); 1853 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1854 assert(objtmp.needed == NULL); 1855#if !defined(__mips__) 1856 /* MIPS has a bogus DT_TEXTREL. */ 1857 assert(!objtmp.textrel); 1858#endif 1859 1860 /* 1861 * Temporarily put the dynamic linker entry into the object list, so 1862 * that symbols can be found. 1863 */ 1864 1865 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1866 } 1867 1868 /* Initialize the object list. */ 1869 obj_tail = &obj_list; 1870 1871 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1872 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1873 1874#ifndef RTLD_INIT_PAGESIZES_EARLY 1875 /* The page size is required by the dynamic memory allocator. */ 1876 init_pagesizes(aux_info); 1877#endif 1878 1879 if (aux_info[AT_OSRELDATE] != NULL) 1880 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1881 1882 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1883 1884 /* Replace the path with a dynamically allocated copy. */ 1885 obj_rtld.path = xstrdup(PATH_RTLD); 1886 1887 r_debug.r_brk = r_debug_state; 1888 r_debug.r_state = RT_CONSISTENT; 1889} 1890 1891/* 1892 * Retrieve the array of supported page sizes. The kernel provides the page 1893 * sizes in increasing order. 1894 */ 1895static void 1896init_pagesizes(Elf_Auxinfo **aux_info) 1897{ 1898 static size_t psa[MAXPAGESIZES]; 1899 int mib[2]; 1900 size_t len, size; 1901 1902 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1903 NULL) { 1904 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1905 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1906 } else { 1907 len = 2; 1908 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1909 size = sizeof(psa); 1910 else { 1911 /* As a fallback, retrieve the base page size. */ 1912 size = sizeof(psa[0]); 1913 if (aux_info[AT_PAGESZ] != NULL) { 1914 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1915 goto psa_filled; 1916 } else { 1917 mib[0] = CTL_HW; 1918 mib[1] = HW_PAGESIZE; 1919 len = 2; 1920 } 1921 } 1922 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1923 _rtld_error("sysctl for hw.pagesize(s) failed"); 1924 rtld_die(); 1925 } 1926psa_filled: 1927 pagesizes = psa; 1928 } 1929 npagesizes = size / sizeof(pagesizes[0]); 1930 /* Discard any invalid entries at the end of the array. */ 1931 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1932 npagesizes--; 1933} 1934 1935/* 1936 * Add the init functions from a needed object list (and its recursive 1937 * needed objects) to "list". This is not used directly; it is a helper 1938 * function for initlist_add_objects(). The write lock must be held 1939 * when this function is called. 1940 */ 1941static void 1942initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1943{ 1944 /* Recursively process the successor needed objects. */ 1945 if (needed->next != NULL) 1946 initlist_add_neededs(needed->next, list); 1947 1948 /* Process the current needed object. */ 1949 if (needed->obj != NULL) 1950 initlist_add_objects(needed->obj, &needed->obj->next, list); 1951} 1952 1953/* 1954 * Scan all of the DAGs rooted in the range of objects from "obj" to 1955 * "tail" and add their init functions to "list". This recurses over 1956 * the DAGs and ensure the proper init ordering such that each object's 1957 * needed libraries are initialized before the object itself. At the 1958 * same time, this function adds the objects to the global finalization 1959 * list "list_fini" in the opposite order. The write lock must be 1960 * held when this function is called. 1961 */ 1962static void 1963initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1964{ 1965 1966 if (obj->init_scanned || obj->init_done) 1967 return; 1968 obj->init_scanned = true; 1969 1970 /* Recursively process the successor objects. */ 1971 if (&obj->next != tail) 1972 initlist_add_objects(obj->next, tail, list); 1973 1974 /* Recursively process the needed objects. */ 1975 if (obj->needed != NULL) 1976 initlist_add_neededs(obj->needed, list); 1977 if (obj->needed_filtees != NULL) 1978 initlist_add_neededs(obj->needed_filtees, list); 1979 if (obj->needed_aux_filtees != NULL) 1980 initlist_add_neededs(obj->needed_aux_filtees, list); 1981 1982 /* Add the object to the init list. */ 1983 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1984 obj->init_array != (Elf_Addr)NULL) 1985 objlist_push_tail(list, obj); 1986 1987 /* Add the object to the global fini list in the reverse order. */ 1988 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1989 && !obj->on_fini_list) { 1990 objlist_push_head(&list_fini, obj); 1991 obj->on_fini_list = true; 1992 } 1993} 1994 1995#ifndef FPTR_TARGET 1996#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1997#endif 1998 1999static void 2000free_needed_filtees(Needed_Entry *n) 2001{ 2002 Needed_Entry *needed, *needed1; 2003 2004 for (needed = n; needed != NULL; needed = needed->next) { 2005 if (needed->obj != NULL) { 2006 dlclose(needed->obj); 2007 needed->obj = NULL; 2008 } 2009 } 2010 for (needed = n; needed != NULL; needed = needed1) { 2011 needed1 = needed->next; 2012 free(needed); 2013 } 2014} 2015 2016static void 2017unload_filtees(Obj_Entry *obj) 2018{ 2019 2020 free_needed_filtees(obj->needed_filtees); 2021 obj->needed_filtees = NULL; 2022 free_needed_filtees(obj->needed_aux_filtees); 2023 obj->needed_aux_filtees = NULL; 2024 obj->filtees_loaded = false; 2025} 2026 2027static void 2028load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2029 RtldLockState *lockstate) 2030{ 2031 2032 for (; needed != NULL; needed = needed->next) { 2033 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2034 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2035 RTLD_LOCAL, lockstate); 2036 } 2037} 2038 2039static void 2040load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2041{ 2042 2043 lock_restart_for_upgrade(lockstate); 2044 if (!obj->filtees_loaded) { 2045 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2046 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2047 obj->filtees_loaded = true; 2048 } 2049} 2050 2051static int 2052process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2053{ 2054 Obj_Entry *obj1; 2055 2056 for (; needed != NULL; needed = needed->next) { 2057 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2058 flags & ~RTLD_LO_NOLOAD); 2059 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2060 return (-1); 2061 } 2062 return (0); 2063} 2064 2065/* 2066 * Given a shared object, traverse its list of needed objects, and load 2067 * each of them. Returns 0 on success. Generates an error message and 2068 * returns -1 on failure. 2069 */ 2070static int 2071load_needed_objects(Obj_Entry *first, int flags) 2072{ 2073 Obj_Entry *obj; 2074 2075 for (obj = first; obj != NULL; obj = obj->next) { 2076 if (process_needed(obj, obj->needed, flags) == -1) 2077 return (-1); 2078 } 2079 return (0); 2080} 2081 2082static int 2083load_preload_objects(void) 2084{ 2085 char *p = ld_preload; 2086 Obj_Entry *obj; 2087 static const char delim[] = " \t:;"; 2088 2089 if (p == NULL) 2090 return 0; 2091 2092 p += strspn(p, delim); 2093 while (*p != '\0') { 2094 size_t len = strcspn(p, delim); 2095 char savech; 2096 2097 savech = p[len]; 2098 p[len] = '\0'; 2099 obj = load_object(p, -1, NULL, 0); 2100 if (obj == NULL) 2101 return -1; /* XXX - cleanup */ 2102 obj->z_interpose = true; 2103 p[len] = savech; 2104 p += len; 2105 p += strspn(p, delim); 2106 } 2107 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2108 return 0; 2109} 2110 2111static const char * 2112printable_path(const char *path) 2113{ 2114 2115 return (path == NULL ? "<unknown>" : path); 2116} 2117 2118/* 2119 * Load a shared object into memory, if it is not already loaded. The 2120 * object may be specified by name or by user-supplied file descriptor 2121 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2122 * duplicate is. 2123 * 2124 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2125 * on failure. 2126 */ 2127static Obj_Entry * 2128load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2129{ 2130 Obj_Entry *obj; 2131 int fd; 2132 struct stat sb; 2133 char *path; 2134 2135 if (name != NULL) { 2136 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2137 if (object_match_name(obj, name)) 2138 return (obj); 2139 } 2140 2141 path = find_library(name, refobj); 2142 if (path == NULL) 2143 return (NULL); 2144 } else 2145 path = NULL; 2146 2147 /* 2148 * If we didn't find a match by pathname, or the name is not 2149 * supplied, open the file and check again by device and inode. 2150 * This avoids false mismatches caused by multiple links or ".." 2151 * in pathnames. 2152 * 2153 * To avoid a race, we open the file and use fstat() rather than 2154 * using stat(). 2155 */ 2156 fd = -1; 2157 if (fd_u == -1) { 2158 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2159 _rtld_error("Cannot open \"%s\"", path); 2160 free(path); 2161 return (NULL); 2162 } 2163 } else { 2164 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2165 if (fd == -1) { 2166 _rtld_error("Cannot dup fd"); 2167 free(path); 2168 return (NULL); 2169 } 2170 } 2171 if (fstat(fd, &sb) == -1) { 2172 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2173 close(fd); 2174 free(path); 2175 return NULL; 2176 } 2177 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2178 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2179 break; 2180 if (obj != NULL && name != NULL) { 2181 object_add_name(obj, name); 2182 free(path); 2183 close(fd); 2184 return obj; 2185 } 2186 if (flags & RTLD_LO_NOLOAD) { 2187 free(path); 2188 close(fd); 2189 return (NULL); 2190 } 2191 2192 /* First use of this object, so we must map it in */ 2193 obj = do_load_object(fd, name, path, &sb, flags); 2194 if (obj == NULL) 2195 free(path); 2196 close(fd); 2197 2198 return obj; 2199} 2200 2201static Obj_Entry * 2202do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2203 int flags) 2204{ 2205 Obj_Entry *obj; 2206 struct statfs fs; 2207 2208 /* 2209 * but first, make sure that environment variables haven't been 2210 * used to circumvent the noexec flag on a filesystem. 2211 */ 2212 if (dangerous_ld_env) { 2213 if (fstatfs(fd, &fs) != 0) { 2214 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2215 return NULL; 2216 } 2217 if (fs.f_flags & MNT_NOEXEC) { 2218 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2219 return NULL; 2220 } 2221 } 2222 dbg("loading \"%s\"", printable_path(path)); 2223 obj = map_object(fd, printable_path(path), sbp); 2224 if (obj == NULL) 2225 return NULL; 2226 2227 /* 2228 * If DT_SONAME is present in the object, digest_dynamic2 already 2229 * added it to the object names. 2230 */ 2231 if (name != NULL) 2232 object_add_name(obj, name); 2233 obj->path = path; 2234 digest_dynamic(obj, 0); 2235 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2236 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2237 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2238 RTLD_LO_DLOPEN) { 2239 dbg("refusing to load non-loadable \"%s\"", obj->path); 2240 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2241 munmap(obj->mapbase, obj->mapsize); 2242 obj_free(obj); 2243 return (NULL); 2244 } 2245 2246 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2247 *obj_tail = obj; 2248 obj_tail = &obj->next; 2249 obj_count++; 2250 obj_loads++; 2251 linkmap_add(obj); /* for GDB & dlinfo() */ 2252 max_stack_flags |= obj->stack_flags; 2253 2254 dbg(" %p .. %p: %s", obj->mapbase, 2255 obj->mapbase + obj->mapsize - 1, obj->path); 2256 if (obj->textrel) 2257 dbg(" WARNING: %s has impure text", obj->path); 2258 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2259 obj->path); 2260 2261 return obj; 2262} 2263 2264static Obj_Entry * 2265obj_from_addr(const void *addr) 2266{ 2267 Obj_Entry *obj; 2268 2269 for (obj = obj_list; obj != NULL; obj = obj->next) { 2270 if (addr < (void *) obj->mapbase) 2271 continue; 2272 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2273 return obj; 2274 } 2275 return NULL; 2276} 2277 2278static void 2279preinit_main(void) 2280{ 2281 Elf_Addr *preinit_addr; 2282 int index; 2283 2284 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2285 if (preinit_addr == NULL) 2286 return; 2287 2288 for (index = 0; index < obj_main->preinit_array_num; index++) { 2289 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2290 dbg("calling preinit function for %s at %p", obj_main->path, 2291 (void *)preinit_addr[index]); 2292 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2293 0, 0, obj_main->path); 2294 call_init_pointer(obj_main, preinit_addr[index]); 2295 } 2296 } 2297} 2298 2299/* 2300 * Call the finalization functions for each of the objects in "list" 2301 * belonging to the DAG of "root" and referenced once. If NULL "root" 2302 * is specified, every finalization function will be called regardless 2303 * of the reference count and the list elements won't be freed. All of 2304 * the objects are expected to have non-NULL fini functions. 2305 */ 2306static void 2307objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2308{ 2309 Objlist_Entry *elm; 2310 char *saved_msg; 2311 Elf_Addr *fini_addr; 2312 int index; 2313 2314 assert(root == NULL || root->refcount == 1); 2315 2316 /* 2317 * Preserve the current error message since a fini function might 2318 * call into the dynamic linker and overwrite it. 2319 */ 2320 saved_msg = errmsg_save(); 2321 do { 2322 STAILQ_FOREACH(elm, list, link) { 2323 if (root != NULL && (elm->obj->refcount != 1 || 2324 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2325 continue; 2326 /* Remove object from fini list to prevent recursive invocation. */ 2327 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2328 /* 2329 * XXX: If a dlopen() call references an object while the 2330 * fini function is in progress, we might end up trying to 2331 * unload the referenced object in dlclose() or the object 2332 * won't be unloaded although its fini function has been 2333 * called. 2334 */ 2335 lock_release(rtld_bind_lock, lockstate); 2336 2337 /* 2338 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2339 * When this happens, DT_FINI_ARRAY is processed first. 2340 */ 2341 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2342 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2343 for (index = elm->obj->fini_array_num - 1; index >= 0; 2344 index--) { 2345 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2346 dbg("calling fini function for %s at %p", 2347 elm->obj->path, (void *)fini_addr[index]); 2348 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2349 (void *)fini_addr[index], 0, 0, elm->obj->path); 2350 call_initfini_pointer(elm->obj, fini_addr[index]); 2351 } 2352 } 2353 } 2354 if (elm->obj->fini != (Elf_Addr)NULL) { 2355 dbg("calling fini function for %s at %p", elm->obj->path, 2356 (void *)elm->obj->fini); 2357 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2358 0, 0, elm->obj->path); 2359 call_initfini_pointer(elm->obj, elm->obj->fini); 2360 } 2361 wlock_acquire(rtld_bind_lock, lockstate); 2362 /* No need to free anything if process is going down. */ 2363 if (root != NULL) 2364 free(elm); 2365 /* 2366 * We must restart the list traversal after every fini call 2367 * because a dlclose() call from the fini function or from 2368 * another thread might have modified the reference counts. 2369 */ 2370 break; 2371 } 2372 } while (elm != NULL); 2373 errmsg_restore(saved_msg); 2374} 2375 2376/* 2377 * Call the initialization functions for each of the objects in 2378 * "list". All of the objects are expected to have non-NULL init 2379 * functions. 2380 */ 2381static void 2382objlist_call_init(Objlist *list, RtldLockState *lockstate) 2383{ 2384 Objlist_Entry *elm; 2385 Obj_Entry *obj; 2386 char *saved_msg; 2387 Elf_Addr *init_addr; 2388 int index; 2389 2390 /* 2391 * Clean init_scanned flag so that objects can be rechecked and 2392 * possibly initialized earlier if any of vectors called below 2393 * cause the change by using dlopen. 2394 */ 2395 for (obj = obj_list; obj != NULL; obj = obj->next) 2396 obj->init_scanned = false; 2397 2398 /* 2399 * Preserve the current error message since an init function might 2400 * call into the dynamic linker and overwrite it. 2401 */ 2402 saved_msg = errmsg_save(); 2403 STAILQ_FOREACH(elm, list, link) { 2404 if (elm->obj->init_done) /* Initialized early. */ 2405 continue; 2406 /* 2407 * Race: other thread might try to use this object before current 2408 * one completes the initilization. Not much can be done here 2409 * without better locking. 2410 */ 2411 elm->obj->init_done = true; 2412 lock_release(rtld_bind_lock, lockstate); 2413 2414 /* 2415 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2416 * When this happens, DT_INIT is processed first. 2417 */ 2418 if (elm->obj->init != (Elf_Addr)NULL) { 2419 dbg("calling init function for %s at %p", elm->obj->path, 2420 (void *)elm->obj->init); 2421 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2422 0, 0, elm->obj->path); 2423 call_initfini_pointer(elm->obj, elm->obj->init); 2424 } 2425 init_addr = (Elf_Addr *)elm->obj->init_array; 2426 if (init_addr != NULL) { 2427 for (index = 0; index < elm->obj->init_array_num; index++) { 2428 if (init_addr[index] != 0 && init_addr[index] != 1) { 2429 dbg("calling init function for %s at %p", elm->obj->path, 2430 (void *)init_addr[index]); 2431 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2432 (void *)init_addr[index], 0, 0, elm->obj->path); 2433 call_init_pointer(elm->obj, init_addr[index]); 2434 } 2435 } 2436 } 2437 wlock_acquire(rtld_bind_lock, lockstate); 2438 } 2439 errmsg_restore(saved_msg); 2440} 2441 2442static void 2443objlist_clear(Objlist *list) 2444{ 2445 Objlist_Entry *elm; 2446 2447 while (!STAILQ_EMPTY(list)) { 2448 elm = STAILQ_FIRST(list); 2449 STAILQ_REMOVE_HEAD(list, link); 2450 free(elm); 2451 } 2452} 2453 2454static Objlist_Entry * 2455objlist_find(Objlist *list, const Obj_Entry *obj) 2456{ 2457 Objlist_Entry *elm; 2458 2459 STAILQ_FOREACH(elm, list, link) 2460 if (elm->obj == obj) 2461 return elm; 2462 return NULL; 2463} 2464 2465static void 2466objlist_init(Objlist *list) 2467{ 2468 STAILQ_INIT(list); 2469} 2470 2471static void 2472objlist_push_head(Objlist *list, Obj_Entry *obj) 2473{ 2474 Objlist_Entry *elm; 2475 2476 elm = NEW(Objlist_Entry); 2477 elm->obj = obj; 2478 STAILQ_INSERT_HEAD(list, elm, link); 2479} 2480 2481static void 2482objlist_push_tail(Objlist *list, Obj_Entry *obj) 2483{ 2484 Objlist_Entry *elm; 2485 2486 elm = NEW(Objlist_Entry); 2487 elm->obj = obj; 2488 STAILQ_INSERT_TAIL(list, elm, link); 2489} 2490 2491static void 2492objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2493{ 2494 Objlist_Entry *elm, *listelm; 2495 2496 STAILQ_FOREACH(listelm, list, link) { 2497 if (listelm->obj == listobj) 2498 break; 2499 } 2500 elm = NEW(Objlist_Entry); 2501 elm->obj = obj; 2502 if (listelm != NULL) 2503 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2504 else 2505 STAILQ_INSERT_TAIL(list, elm, link); 2506} 2507 2508static void 2509objlist_remove(Objlist *list, Obj_Entry *obj) 2510{ 2511 Objlist_Entry *elm; 2512 2513 if ((elm = objlist_find(list, obj)) != NULL) { 2514 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2515 free(elm); 2516 } 2517} 2518 2519/* 2520 * Relocate dag rooted in the specified object. 2521 * Returns 0 on success, or -1 on failure. 2522 */ 2523 2524static int 2525relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2526 int flags, RtldLockState *lockstate) 2527{ 2528 Objlist_Entry *elm; 2529 int error; 2530 2531 error = 0; 2532 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2533 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2534 lockstate); 2535 if (error == -1) 2536 break; 2537 } 2538 return (error); 2539} 2540 2541/* 2542 * Relocate single object. 2543 * Returns 0 on success, or -1 on failure. 2544 */ 2545static int 2546relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2547 int flags, RtldLockState *lockstate) 2548{ 2549 2550 if (obj->relocated) 2551 return (0); 2552 obj->relocated = true; 2553 if (obj != rtldobj) 2554 dbg("relocating \"%s\"", obj->path); 2555 2556 if (obj->symtab == NULL || obj->strtab == NULL || 2557 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2558 _rtld_error("%s: Shared object has no run-time symbol table", 2559 obj->path); 2560 return (-1); 2561 } 2562 2563 if (obj->textrel) { 2564 /* There are relocations to the write-protected text segment. */ 2565 if (mprotect(obj->mapbase, obj->textsize, 2566 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2567 _rtld_error("%s: Cannot write-enable text segment: %s", 2568 obj->path, rtld_strerror(errno)); 2569 return (-1); 2570 } 2571 } 2572 2573 /* Process the non-PLT non-IFUNC relocations. */ 2574 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2575 return (-1); 2576 2577 if (obj->textrel) { /* Re-protected the text segment. */ 2578 if (mprotect(obj->mapbase, obj->textsize, 2579 PROT_READ|PROT_EXEC) == -1) { 2580 _rtld_error("%s: Cannot write-protect text segment: %s", 2581 obj->path, rtld_strerror(errno)); 2582 return (-1); 2583 } 2584 } 2585 2586 /* Set the special PLT or GOT entries. */ 2587 init_pltgot(obj); 2588 2589 /* Process the PLT relocations. */ 2590 if (reloc_plt(obj) == -1) 2591 return (-1); 2592 /* Relocate the jump slots if we are doing immediate binding. */ 2593 if (obj->bind_now || bind_now) 2594 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2595 return (-1); 2596 2597 /* 2598 * Process the non-PLT IFUNC relocations. The relocations are 2599 * processed in two phases, because IFUNC resolvers may 2600 * reference other symbols, which must be readily processed 2601 * before resolvers are called. 2602 */ 2603 if (obj->non_plt_gnu_ifunc && 2604 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2605 return (-1); 2606 2607 if (obj->relro_size > 0) { 2608 if (mprotect(obj->relro_page, obj->relro_size, 2609 PROT_READ) == -1) { 2610 _rtld_error("%s: Cannot enforce relro protection: %s", 2611 obj->path, rtld_strerror(errno)); 2612 return (-1); 2613 } 2614 } 2615 2616 /* 2617 * Set up the magic number and version in the Obj_Entry. These 2618 * were checked in the crt1.o from the original ElfKit, so we 2619 * set them for backward compatibility. 2620 */ 2621 obj->magic = RTLD_MAGIC; 2622 obj->version = RTLD_VERSION; 2623 2624 return (0); 2625} 2626 2627/* 2628 * Relocate newly-loaded shared objects. The argument is a pointer to 2629 * the Obj_Entry for the first such object. All objects from the first 2630 * to the end of the list of objects are relocated. Returns 0 on success, 2631 * or -1 on failure. 2632 */ 2633static int 2634relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2635 int flags, RtldLockState *lockstate) 2636{ 2637 Obj_Entry *obj; 2638 int error; 2639 2640 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2641 error = relocate_object(obj, bind_now, rtldobj, flags, 2642 lockstate); 2643 if (error == -1) 2644 break; 2645 } 2646 return (error); 2647} 2648 2649/* 2650 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2651 * referencing STT_GNU_IFUNC symbols is postponed till the other 2652 * relocations are done. The indirect functions specified as 2653 * ifunc are allowed to call other symbols, so we need to have 2654 * objects relocated before asking for resolution from indirects. 2655 * 2656 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2657 * instead of the usual lazy handling of PLT slots. It is 2658 * consistent with how GNU does it. 2659 */ 2660static int 2661resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2662 RtldLockState *lockstate) 2663{ 2664 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2665 return (-1); 2666 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2667 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2668 return (-1); 2669 return (0); 2670} 2671 2672static int 2673resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2674 RtldLockState *lockstate) 2675{ 2676 Obj_Entry *obj; 2677 2678 for (obj = first; obj != NULL; obj = obj->next) { 2679 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2680 return (-1); 2681 } 2682 return (0); 2683} 2684 2685static int 2686initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2687 RtldLockState *lockstate) 2688{ 2689 Objlist_Entry *elm; 2690 2691 STAILQ_FOREACH(elm, list, link) { 2692 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2693 lockstate) == -1) 2694 return (-1); 2695 } 2696 return (0); 2697} 2698 2699/* 2700 * Cleanup procedure. It will be called (by the atexit mechanism) just 2701 * before the process exits. 2702 */ 2703static void 2704rtld_exit(void) 2705{ 2706 RtldLockState lockstate; 2707 2708 wlock_acquire(rtld_bind_lock, &lockstate); 2709 dbg("rtld_exit()"); 2710 objlist_call_fini(&list_fini, NULL, &lockstate); 2711 /* No need to remove the items from the list, since we are exiting. */ 2712 if (!libmap_disable) 2713 lm_fini(); 2714 lock_release(rtld_bind_lock, &lockstate); 2715} 2716 2717/* 2718 * Iterate over a search path, translate each element, and invoke the 2719 * callback on the result. 2720 */ 2721static void * 2722path_enumerate(const char *path, path_enum_proc callback, void *arg) 2723{ 2724 const char *trans; 2725 if (path == NULL) 2726 return (NULL); 2727 2728 path += strspn(path, ":;"); 2729 while (*path != '\0') { 2730 size_t len; 2731 char *res; 2732 2733 len = strcspn(path, ":;"); 2734 trans = lm_findn(NULL, path, len); 2735 if (trans) 2736 res = callback(trans, strlen(trans), arg); 2737 else 2738 res = callback(path, len, arg); 2739 2740 if (res != NULL) 2741 return (res); 2742 2743 path += len; 2744 path += strspn(path, ":;"); 2745 } 2746 2747 return (NULL); 2748} 2749 2750struct try_library_args { 2751 const char *name; 2752 size_t namelen; 2753 char *buffer; 2754 size_t buflen; 2755}; 2756 2757static void * 2758try_library_path(const char *dir, size_t dirlen, void *param) 2759{ 2760 struct try_library_args *arg; 2761 2762 arg = param; 2763 if (*dir == '/' || trust) { 2764 char *pathname; 2765 2766 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2767 return (NULL); 2768 2769 pathname = arg->buffer; 2770 strncpy(pathname, dir, dirlen); 2771 pathname[dirlen] = '/'; 2772 strcpy(pathname + dirlen + 1, arg->name); 2773 2774 dbg(" Trying \"%s\"", pathname); 2775 if (access(pathname, F_OK) == 0) { /* We found it */ 2776 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2777 strcpy(pathname, arg->buffer); 2778 return (pathname); 2779 } 2780 } 2781 return (NULL); 2782} 2783 2784static char * 2785search_library_path(const char *name, const char *path) 2786{ 2787 char *p; 2788 struct try_library_args arg; 2789 2790 if (path == NULL) 2791 return NULL; 2792 2793 arg.name = name; 2794 arg.namelen = strlen(name); 2795 arg.buffer = xmalloc(PATH_MAX); 2796 arg.buflen = PATH_MAX; 2797 2798 p = path_enumerate(path, try_library_path, &arg); 2799 2800 free(arg.buffer); 2801 2802 return (p); 2803} 2804 2805int 2806dlclose(void *handle) 2807{ 2808 Obj_Entry *root; 2809 RtldLockState lockstate; 2810 2811 wlock_acquire(rtld_bind_lock, &lockstate); 2812 root = dlcheck(handle); 2813 if (root == NULL) { 2814 lock_release(rtld_bind_lock, &lockstate); 2815 return -1; 2816 } 2817 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2818 root->path); 2819 2820 /* Unreference the object and its dependencies. */ 2821 root->dl_refcount--; 2822 2823 if (root->refcount == 1) { 2824 /* 2825 * The object will be no longer referenced, so we must unload it. 2826 * First, call the fini functions. 2827 */ 2828 objlist_call_fini(&list_fini, root, &lockstate); 2829 2830 unref_dag(root); 2831 2832 /* Finish cleaning up the newly-unreferenced objects. */ 2833 GDB_STATE(RT_DELETE,&root->linkmap); 2834 unload_object(root); 2835 GDB_STATE(RT_CONSISTENT,NULL); 2836 } else 2837 unref_dag(root); 2838 2839 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2840 lock_release(rtld_bind_lock, &lockstate); 2841 return 0; 2842} 2843 2844char * 2845dlerror(void) 2846{ 2847 char *msg = error_message; 2848 error_message = NULL; 2849 return msg; 2850} 2851 2852/* 2853 * This function is deprecated and has no effect. 2854 */ 2855void 2856dllockinit(void *context, 2857 void *(*lock_create)(void *context), 2858 void (*rlock_acquire)(void *lock), 2859 void (*wlock_acquire)(void *lock), 2860 void (*lock_release)(void *lock), 2861 void (*lock_destroy)(void *lock), 2862 void (*context_destroy)(void *context)) 2863{ 2864 static void *cur_context; 2865 static void (*cur_context_destroy)(void *); 2866 2867 /* Just destroy the context from the previous call, if necessary. */ 2868 if (cur_context_destroy != NULL) 2869 cur_context_destroy(cur_context); 2870 cur_context = context; 2871 cur_context_destroy = context_destroy; 2872} 2873 2874void * 2875dlopen(const char *name, int mode) 2876{ 2877 2878 return (rtld_dlopen(name, -1, mode)); 2879} 2880 2881void * 2882fdlopen(int fd, int mode) 2883{ 2884 2885 return (rtld_dlopen(NULL, fd, mode)); 2886} 2887 2888static void * 2889rtld_dlopen(const char *name, int fd, int mode) 2890{ 2891 RtldLockState lockstate; 2892 int lo_flags; 2893 2894 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2895 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2896 if (ld_tracing != NULL) { 2897 rlock_acquire(rtld_bind_lock, &lockstate); 2898 if (sigsetjmp(lockstate.env, 0) != 0) 2899 lock_upgrade(rtld_bind_lock, &lockstate); 2900 environ = (char **)*get_program_var_addr("environ", &lockstate); 2901 lock_release(rtld_bind_lock, &lockstate); 2902 } 2903 lo_flags = RTLD_LO_DLOPEN; 2904 if (mode & RTLD_NODELETE) 2905 lo_flags |= RTLD_LO_NODELETE; 2906 if (mode & RTLD_NOLOAD) 2907 lo_flags |= RTLD_LO_NOLOAD; 2908 if (ld_tracing != NULL) 2909 lo_flags |= RTLD_LO_TRACE; 2910 2911 return (dlopen_object(name, fd, obj_main, lo_flags, 2912 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2913} 2914 2915static void 2916dlopen_cleanup(Obj_Entry *obj) 2917{ 2918 2919 obj->dl_refcount--; 2920 unref_dag(obj); 2921 if (obj->refcount == 0) 2922 unload_object(obj); 2923} 2924 2925static Obj_Entry * 2926dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2927 int mode, RtldLockState *lockstate) 2928{ 2929 Obj_Entry **old_obj_tail; 2930 Obj_Entry *obj; 2931 Objlist initlist; 2932 RtldLockState mlockstate; 2933 int result; 2934 2935 objlist_init(&initlist); 2936 2937 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2938 wlock_acquire(rtld_bind_lock, &mlockstate); 2939 lockstate = &mlockstate; 2940 } 2941 GDB_STATE(RT_ADD,NULL); 2942 2943 old_obj_tail = obj_tail; 2944 obj = NULL; 2945 if (name == NULL && fd == -1) { 2946 obj = obj_main; 2947 obj->refcount++; 2948 } else { 2949 obj = load_object(name, fd, refobj, lo_flags); 2950 } 2951 2952 if (obj) { 2953 obj->dl_refcount++; 2954 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2955 objlist_push_tail(&list_global, obj); 2956 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2957 assert(*old_obj_tail == obj); 2958 result = load_needed_objects(obj, 2959 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2960 init_dag(obj); 2961 ref_dag(obj); 2962 if (result != -1) 2963 result = rtld_verify_versions(&obj->dagmembers); 2964 if (result != -1 && ld_tracing) 2965 goto trace; 2966 if (result == -1 || relocate_object_dag(obj, 2967 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2968 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2969 lockstate) == -1) { 2970 dlopen_cleanup(obj); 2971 obj = NULL; 2972 } else if (lo_flags & RTLD_LO_EARLY) { 2973 /* 2974 * Do not call the init functions for early loaded 2975 * filtees. The image is still not initialized enough 2976 * for them to work. 2977 * 2978 * Our object is found by the global object list and 2979 * will be ordered among all init calls done right 2980 * before transferring control to main. 2981 */ 2982 } else { 2983 /* Make list of init functions to call. */ 2984 initlist_add_objects(obj, &obj->next, &initlist); 2985 } 2986 /* 2987 * Process all no_delete or global objects here, given 2988 * them own DAGs to prevent their dependencies from being 2989 * unloaded. This has to be done after we have loaded all 2990 * of the dependencies, so that we do not miss any. 2991 */ 2992 if (obj != NULL) 2993 process_z(obj); 2994 } else { 2995 /* 2996 * Bump the reference counts for objects on this DAG. If 2997 * this is the first dlopen() call for the object that was 2998 * already loaded as a dependency, initialize the dag 2999 * starting at it. 3000 */ 3001 init_dag(obj); 3002 ref_dag(obj); 3003 3004 if ((lo_flags & RTLD_LO_TRACE) != 0) 3005 goto trace; 3006 } 3007 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3008 obj->z_nodelete) && !obj->ref_nodel) { 3009 dbg("obj %s nodelete", obj->path); 3010 ref_dag(obj); 3011 obj->z_nodelete = obj->ref_nodel = true; 3012 } 3013 } 3014 3015 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3016 name); 3017 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3018 3019 if (!(lo_flags & RTLD_LO_EARLY)) { 3020 map_stacks_exec(lockstate); 3021 } 3022 3023 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3024 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3025 lockstate) == -1) { 3026 objlist_clear(&initlist); 3027 dlopen_cleanup(obj); 3028 if (lockstate == &mlockstate) 3029 lock_release(rtld_bind_lock, lockstate); 3030 return (NULL); 3031 } 3032 3033 if (!(lo_flags & RTLD_LO_EARLY)) { 3034 /* Call the init functions. */ 3035 objlist_call_init(&initlist, lockstate); 3036 } 3037 objlist_clear(&initlist); 3038 if (lockstate == &mlockstate) 3039 lock_release(rtld_bind_lock, lockstate); 3040 return obj; 3041trace: 3042 trace_loaded_objects(obj); 3043 if (lockstate == &mlockstate) 3044 lock_release(rtld_bind_lock, lockstate); 3045 exit(0); 3046} 3047 3048static void * 3049do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3050 int flags) 3051{ 3052 DoneList donelist; 3053 const Obj_Entry *obj, *defobj; 3054 const Elf_Sym *def; 3055 SymLook req; 3056 RtldLockState lockstate; 3057#ifndef __ia64__ 3058 tls_index ti; 3059#endif 3060 void *sym; 3061 int res; 3062 3063 def = NULL; 3064 defobj = NULL; 3065 symlook_init(&req, name); 3066 req.ventry = ve; 3067 req.flags = flags | SYMLOOK_IN_PLT; 3068 req.lockstate = &lockstate; 3069 3070 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3071 rlock_acquire(rtld_bind_lock, &lockstate); 3072 if (sigsetjmp(lockstate.env, 0) != 0) 3073 lock_upgrade(rtld_bind_lock, &lockstate); 3074 if (handle == NULL || handle == RTLD_NEXT || 3075 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3076 3077 if ((obj = obj_from_addr(retaddr)) == NULL) { 3078 _rtld_error("Cannot determine caller's shared object"); 3079 lock_release(rtld_bind_lock, &lockstate); 3080 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3081 return NULL; 3082 } 3083 if (handle == NULL) { /* Just the caller's shared object. */ 3084 res = symlook_obj(&req, obj); 3085 if (res == 0) { 3086 def = req.sym_out; 3087 defobj = req.defobj_out; 3088 } 3089 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3090 handle == RTLD_SELF) { /* ... caller included */ 3091 if (handle == RTLD_NEXT) 3092 obj = obj->next; 3093 for (; obj != NULL; obj = obj->next) { 3094 res = symlook_obj(&req, obj); 3095 if (res == 0) { 3096 if (def == NULL || 3097 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3098 def = req.sym_out; 3099 defobj = req.defobj_out; 3100 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3101 break; 3102 } 3103 } 3104 } 3105 /* 3106 * Search the dynamic linker itself, and possibly resolve the 3107 * symbol from there. This is how the application links to 3108 * dynamic linker services such as dlopen. 3109 */ 3110 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3111 res = symlook_obj(&req, &obj_rtld); 3112 if (res == 0) { 3113 def = req.sym_out; 3114 defobj = req.defobj_out; 3115 } 3116 } 3117 } else { 3118 assert(handle == RTLD_DEFAULT); 3119 res = symlook_default(&req, obj); 3120 if (res == 0) { 3121 defobj = req.defobj_out; 3122 def = req.sym_out; 3123 } 3124 } 3125 } else { 3126 if ((obj = dlcheck(handle)) == NULL) { 3127 lock_release(rtld_bind_lock, &lockstate); 3128 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3129 return NULL; 3130 } 3131 3132 donelist_init(&donelist); 3133 if (obj->mainprog) { 3134 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3135 res = symlook_global(&req, &donelist); 3136 if (res == 0) { 3137 def = req.sym_out; 3138 defobj = req.defobj_out; 3139 } 3140 /* 3141 * Search the dynamic linker itself, and possibly resolve the 3142 * symbol from there. This is how the application links to 3143 * dynamic linker services such as dlopen. 3144 */ 3145 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3146 res = symlook_obj(&req, &obj_rtld); 3147 if (res == 0) { 3148 def = req.sym_out; 3149 defobj = req.defobj_out; 3150 } 3151 } 3152 } 3153 else { 3154 /* Search the whole DAG rooted at the given object. */ 3155 res = symlook_list(&req, &obj->dagmembers, &donelist); 3156 if (res == 0) { 3157 def = req.sym_out; 3158 defobj = req.defobj_out; 3159 } 3160 } 3161 } 3162 3163 if (def != NULL) { 3164 lock_release(rtld_bind_lock, &lockstate); 3165 3166 /* 3167 * The value required by the caller is derived from the value 3168 * of the symbol. For the ia64 architecture, we need to 3169 * construct a function descriptor which the caller can use to 3170 * call the function with the right 'gp' value. For other 3171 * architectures and for non-functions, the value is simply 3172 * the relocated value of the symbol. 3173 */ 3174 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3175 sym = make_function_pointer(def, defobj); 3176 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3177 sym = rtld_resolve_ifunc(defobj, def); 3178 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3179#ifdef __ia64__ 3180 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3181#else 3182 ti.ti_module = defobj->tlsindex; 3183 ti.ti_offset = def->st_value; 3184 sym = __tls_get_addr(&ti); 3185#endif 3186 } else 3187 sym = defobj->relocbase + def->st_value; 3188 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3189 return (sym); 3190 } 3191 3192 _rtld_error("Undefined symbol \"%s\"", name); 3193 lock_release(rtld_bind_lock, &lockstate); 3194 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3195 return NULL; 3196} 3197 3198void * 3199dlsym(void *handle, const char *name) 3200{ 3201 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3202 SYMLOOK_DLSYM); 3203} 3204 3205dlfunc_t 3206dlfunc(void *handle, const char *name) 3207{ 3208 union { 3209 void *d; 3210 dlfunc_t f; 3211 } rv; 3212 3213 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3214 SYMLOOK_DLSYM); 3215 return (rv.f); 3216} 3217 3218void * 3219dlvsym(void *handle, const char *name, const char *version) 3220{ 3221 Ver_Entry ventry; 3222 3223 ventry.name = version; 3224 ventry.file = NULL; 3225 ventry.hash = elf_hash(version); 3226 ventry.flags= 0; 3227 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3228 SYMLOOK_DLSYM); 3229} 3230 3231int 3232_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3233{ 3234 const Obj_Entry *obj; 3235 RtldLockState lockstate; 3236 3237 rlock_acquire(rtld_bind_lock, &lockstate); 3238 obj = obj_from_addr(addr); 3239 if (obj == NULL) { 3240 _rtld_error("No shared object contains address"); 3241 lock_release(rtld_bind_lock, &lockstate); 3242 return (0); 3243 } 3244 rtld_fill_dl_phdr_info(obj, phdr_info); 3245 lock_release(rtld_bind_lock, &lockstate); 3246 return (1); 3247} 3248 3249int 3250dladdr(const void *addr, Dl_info *info) 3251{ 3252 const Obj_Entry *obj; 3253 const Elf_Sym *def; 3254 void *symbol_addr; 3255 unsigned long symoffset; 3256 RtldLockState lockstate; 3257 3258 rlock_acquire(rtld_bind_lock, &lockstate); 3259 obj = obj_from_addr(addr); 3260 if (obj == NULL) { 3261 _rtld_error("No shared object contains address"); 3262 lock_release(rtld_bind_lock, &lockstate); 3263 return 0; 3264 } 3265 info->dli_fname = obj->path; 3266 info->dli_fbase = obj->mapbase; 3267 info->dli_saddr = (void *)0; 3268 info->dli_sname = NULL; 3269 3270 /* 3271 * Walk the symbol list looking for the symbol whose address is 3272 * closest to the address sent in. 3273 */ 3274 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3275 def = obj->symtab + symoffset; 3276 3277 /* 3278 * For skip the symbol if st_shndx is either SHN_UNDEF or 3279 * SHN_COMMON. 3280 */ 3281 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3282 continue; 3283 3284 /* 3285 * If the symbol is greater than the specified address, or if it 3286 * is further away from addr than the current nearest symbol, 3287 * then reject it. 3288 */ 3289 symbol_addr = obj->relocbase + def->st_value; 3290 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3291 continue; 3292 3293 /* Update our idea of the nearest symbol. */ 3294 info->dli_sname = obj->strtab + def->st_name; 3295 info->dli_saddr = symbol_addr; 3296 3297 /* Exact match? */ 3298 if (info->dli_saddr == addr) 3299 break; 3300 } 3301 lock_release(rtld_bind_lock, &lockstate); 3302 return 1; 3303} 3304 3305int 3306dlinfo(void *handle, int request, void *p) 3307{ 3308 const Obj_Entry *obj; 3309 RtldLockState lockstate; 3310 int error; 3311 3312 rlock_acquire(rtld_bind_lock, &lockstate); 3313 3314 if (handle == NULL || handle == RTLD_SELF) { 3315 void *retaddr; 3316 3317 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3318 if ((obj = obj_from_addr(retaddr)) == NULL) 3319 _rtld_error("Cannot determine caller's shared object"); 3320 } else 3321 obj = dlcheck(handle); 3322 3323 if (obj == NULL) { 3324 lock_release(rtld_bind_lock, &lockstate); 3325 return (-1); 3326 } 3327 3328 error = 0; 3329 switch (request) { 3330 case RTLD_DI_LINKMAP: 3331 *((struct link_map const **)p) = &obj->linkmap; 3332 break; 3333 case RTLD_DI_ORIGIN: 3334 error = rtld_dirname(obj->path, p); 3335 break; 3336 3337 case RTLD_DI_SERINFOSIZE: 3338 case RTLD_DI_SERINFO: 3339 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3340 break; 3341 3342 default: 3343 _rtld_error("Invalid request %d passed to dlinfo()", request); 3344 error = -1; 3345 } 3346 3347 lock_release(rtld_bind_lock, &lockstate); 3348 3349 return (error); 3350} 3351 3352static void 3353rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3354{ 3355 3356 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3357 phdr_info->dlpi_name = obj->path; 3358 phdr_info->dlpi_phdr = obj->phdr; 3359 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3360 phdr_info->dlpi_tls_modid = obj->tlsindex; 3361 phdr_info->dlpi_tls_data = obj->tlsinit; 3362 phdr_info->dlpi_adds = obj_loads; 3363 phdr_info->dlpi_subs = obj_loads - obj_count; 3364} 3365 3366int 3367dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3368{ 3369 struct dl_phdr_info phdr_info; 3370 const Obj_Entry *obj; 3371 RtldLockState bind_lockstate, phdr_lockstate; 3372 int error; 3373 3374 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3375 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3376 3377 error = 0; 3378 3379 for (obj = obj_list; obj != NULL; obj = obj->next) { 3380 rtld_fill_dl_phdr_info(obj, &phdr_info); 3381 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3382 break; 3383 3384 } 3385 lock_release(rtld_bind_lock, &bind_lockstate); 3386 lock_release(rtld_phdr_lock, &phdr_lockstate); 3387 3388 return (error); 3389} 3390 3391static void * 3392fill_search_info(const char *dir, size_t dirlen, void *param) 3393{ 3394 struct fill_search_info_args *arg; 3395 3396 arg = param; 3397 3398 if (arg->request == RTLD_DI_SERINFOSIZE) { 3399 arg->serinfo->dls_cnt ++; 3400 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3401 } else { 3402 struct dl_serpath *s_entry; 3403 3404 s_entry = arg->serpath; 3405 s_entry->dls_name = arg->strspace; 3406 s_entry->dls_flags = arg->flags; 3407 3408 strncpy(arg->strspace, dir, dirlen); 3409 arg->strspace[dirlen] = '\0'; 3410 3411 arg->strspace += dirlen + 1; 3412 arg->serpath++; 3413 } 3414 3415 return (NULL); 3416} 3417 3418static int 3419do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3420{ 3421 struct dl_serinfo _info; 3422 struct fill_search_info_args args; 3423 3424 args.request = RTLD_DI_SERINFOSIZE; 3425 args.serinfo = &_info; 3426 3427 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3428 _info.dls_cnt = 0; 3429 3430 path_enumerate(obj->rpath, fill_search_info, &args); 3431 path_enumerate(ld_library_path, fill_search_info, &args); 3432 path_enumerate(obj->runpath, fill_search_info, &args); 3433 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3434 if (!obj->z_nodeflib) 3435 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3436 3437 3438 if (request == RTLD_DI_SERINFOSIZE) { 3439 info->dls_size = _info.dls_size; 3440 info->dls_cnt = _info.dls_cnt; 3441 return (0); 3442 } 3443 3444 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3445 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3446 return (-1); 3447 } 3448 3449 args.request = RTLD_DI_SERINFO; 3450 args.serinfo = info; 3451 args.serpath = &info->dls_serpath[0]; 3452 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3453 3454 args.flags = LA_SER_RUNPATH; 3455 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3456 return (-1); 3457 3458 args.flags = LA_SER_LIBPATH; 3459 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3460 return (-1); 3461 3462 args.flags = LA_SER_RUNPATH; 3463 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3464 return (-1); 3465 3466 args.flags = LA_SER_CONFIG; 3467 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3468 != NULL) 3469 return (-1); 3470 3471 args.flags = LA_SER_DEFAULT; 3472 if (!obj->z_nodeflib && 3473 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3474 return (-1); 3475 return (0); 3476} 3477 3478static int 3479rtld_dirname(const char *path, char *bname) 3480{ 3481 const char *endp; 3482 3483 /* Empty or NULL string gets treated as "." */ 3484 if (path == NULL || *path == '\0') { 3485 bname[0] = '.'; 3486 bname[1] = '\0'; 3487 return (0); 3488 } 3489 3490 /* Strip trailing slashes */ 3491 endp = path + strlen(path) - 1; 3492 while (endp > path && *endp == '/') 3493 endp--; 3494 3495 /* Find the start of the dir */ 3496 while (endp > path && *endp != '/') 3497 endp--; 3498 3499 /* Either the dir is "/" or there are no slashes */ 3500 if (endp == path) { 3501 bname[0] = *endp == '/' ? '/' : '.'; 3502 bname[1] = '\0'; 3503 return (0); 3504 } else { 3505 do { 3506 endp--; 3507 } while (endp > path && *endp == '/'); 3508 } 3509 3510 if (endp - path + 2 > PATH_MAX) 3511 { 3512 _rtld_error("Filename is too long: %s", path); 3513 return(-1); 3514 } 3515 3516 strncpy(bname, path, endp - path + 1); 3517 bname[endp - path + 1] = '\0'; 3518 return (0); 3519} 3520 3521static int 3522rtld_dirname_abs(const char *path, char *base) 3523{ 3524 char *last; 3525 3526 if (realpath(path, base) == NULL) 3527 return (-1); 3528 dbg("%s -> %s", path, base); 3529 last = strrchr(base, '/'); 3530 if (last == NULL) 3531 return (-1); 3532 if (last != base) 3533 *last = '\0'; 3534 return (0); 3535} 3536 3537static void 3538linkmap_add(Obj_Entry *obj) 3539{ 3540 struct link_map *l = &obj->linkmap; 3541 struct link_map *prev; 3542 3543 obj->linkmap.l_name = obj->path; 3544 obj->linkmap.l_addr = obj->mapbase; 3545 obj->linkmap.l_ld = obj->dynamic; 3546#ifdef __mips__ 3547 /* GDB needs load offset on MIPS to use the symbols */ 3548 obj->linkmap.l_offs = obj->relocbase; 3549#endif 3550 3551 if (r_debug.r_map == NULL) { 3552 r_debug.r_map = l; 3553 return; 3554 } 3555 3556 /* 3557 * Scan to the end of the list, but not past the entry for the 3558 * dynamic linker, which we want to keep at the very end. 3559 */ 3560 for (prev = r_debug.r_map; 3561 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3562 prev = prev->l_next) 3563 ; 3564 3565 /* Link in the new entry. */ 3566 l->l_prev = prev; 3567 l->l_next = prev->l_next; 3568 if (l->l_next != NULL) 3569 l->l_next->l_prev = l; 3570 prev->l_next = l; 3571} 3572 3573static void 3574linkmap_delete(Obj_Entry *obj) 3575{ 3576 struct link_map *l = &obj->linkmap; 3577 3578 if (l->l_prev == NULL) { 3579 if ((r_debug.r_map = l->l_next) != NULL) 3580 l->l_next->l_prev = NULL; 3581 return; 3582 } 3583 3584 if ((l->l_prev->l_next = l->l_next) != NULL) 3585 l->l_next->l_prev = l->l_prev; 3586} 3587 3588/* 3589 * Function for the debugger to set a breakpoint on to gain control. 3590 * 3591 * The two parameters allow the debugger to easily find and determine 3592 * what the runtime loader is doing and to whom it is doing it. 3593 * 3594 * When the loadhook trap is hit (r_debug_state, set at program 3595 * initialization), the arguments can be found on the stack: 3596 * 3597 * +8 struct link_map *m 3598 * +4 struct r_debug *rd 3599 * +0 RetAddr 3600 */ 3601void 3602r_debug_state(struct r_debug* rd, struct link_map *m) 3603{ 3604 /* 3605 * The following is a hack to force the compiler to emit calls to 3606 * this function, even when optimizing. If the function is empty, 3607 * the compiler is not obliged to emit any code for calls to it, 3608 * even when marked __noinline. However, gdb depends on those 3609 * calls being made. 3610 */ 3611 __compiler_membar(); 3612} 3613 3614/* 3615 * A function called after init routines have completed. This can be used to 3616 * break before a program's entry routine is called, and can be used when 3617 * main is not available in the symbol table. 3618 */ 3619void 3620_r_debug_postinit(struct link_map *m) 3621{ 3622 3623 /* See r_debug_state(). */ 3624 __compiler_membar(); 3625} 3626 3627/* 3628 * Get address of the pointer variable in the main program. 3629 * Prefer non-weak symbol over the weak one. 3630 */ 3631static const void ** 3632get_program_var_addr(const char *name, RtldLockState *lockstate) 3633{ 3634 SymLook req; 3635 DoneList donelist; 3636 3637 symlook_init(&req, name); 3638 req.lockstate = lockstate; 3639 donelist_init(&donelist); 3640 if (symlook_global(&req, &donelist) != 0) 3641 return (NULL); 3642 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3643 return ((const void **)make_function_pointer(req.sym_out, 3644 req.defobj_out)); 3645 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3646 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3647 else 3648 return ((const void **)(req.defobj_out->relocbase + 3649 req.sym_out->st_value)); 3650} 3651 3652/* 3653 * Set a pointer variable in the main program to the given value. This 3654 * is used to set key variables such as "environ" before any of the 3655 * init functions are called. 3656 */ 3657static void 3658set_program_var(const char *name, const void *value) 3659{ 3660 const void **addr; 3661 3662 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3663 dbg("\"%s\": *%p <-- %p", name, addr, value); 3664 *addr = value; 3665 } 3666} 3667 3668/* 3669 * Search the global objects, including dependencies and main object, 3670 * for the given symbol. 3671 */ 3672static int 3673symlook_global(SymLook *req, DoneList *donelist) 3674{ 3675 SymLook req1; 3676 const Objlist_Entry *elm; 3677 int res; 3678 3679 symlook_init_from_req(&req1, req); 3680 3681 /* Search all objects loaded at program start up. */ 3682 if (req->defobj_out == NULL || 3683 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3684 res = symlook_list(&req1, &list_main, donelist); 3685 if (res == 0 && (req->defobj_out == NULL || 3686 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3687 req->sym_out = req1.sym_out; 3688 req->defobj_out = req1.defobj_out; 3689 assert(req->defobj_out != NULL); 3690 } 3691 } 3692 3693 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3694 STAILQ_FOREACH(elm, &list_global, link) { 3695 if (req->defobj_out != NULL && 3696 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3697 break; 3698 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3699 if (res == 0 && (req->defobj_out == NULL || 3700 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3701 req->sym_out = req1.sym_out; 3702 req->defobj_out = req1.defobj_out; 3703 assert(req->defobj_out != NULL); 3704 } 3705 } 3706 3707 return (req->sym_out != NULL ? 0 : ESRCH); 3708} 3709 3710/* 3711 * Given a symbol name in a referencing object, find the corresponding 3712 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3713 * no definition was found. Returns a pointer to the Obj_Entry of the 3714 * defining object via the reference parameter DEFOBJ_OUT. 3715 */ 3716static int 3717symlook_default(SymLook *req, const Obj_Entry *refobj) 3718{ 3719 DoneList donelist; 3720 const Objlist_Entry *elm; 3721 SymLook req1; 3722 int res; 3723 3724 donelist_init(&donelist); 3725 symlook_init_from_req(&req1, req); 3726 3727 /* Look first in the referencing object if linked symbolically. */ 3728 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3729 res = symlook_obj(&req1, refobj); 3730 if (res == 0) { 3731 req->sym_out = req1.sym_out; 3732 req->defobj_out = req1.defobj_out; 3733 assert(req->defobj_out != NULL); 3734 } 3735 } 3736 3737 symlook_global(req, &donelist); 3738 3739 /* Search all dlopened DAGs containing the referencing object. */ 3740 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3741 if (req->sym_out != NULL && 3742 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3743 break; 3744 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3745 if (res == 0 && (req->sym_out == NULL || 3746 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3747 req->sym_out = req1.sym_out; 3748 req->defobj_out = req1.defobj_out; 3749 assert(req->defobj_out != NULL); 3750 } 3751 } 3752 3753 /* 3754 * Search the dynamic linker itself, and possibly resolve the 3755 * symbol from there. This is how the application links to 3756 * dynamic linker services such as dlopen. 3757 */ 3758 if (req->sym_out == NULL || 3759 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3760 res = symlook_obj(&req1, &obj_rtld); 3761 if (res == 0) { 3762 req->sym_out = req1.sym_out; 3763 req->defobj_out = req1.defobj_out; 3764 assert(req->defobj_out != NULL); 3765 } 3766 } 3767 3768 return (req->sym_out != NULL ? 0 : ESRCH); 3769} 3770 3771static int 3772symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3773{ 3774 const Elf_Sym *def; 3775 const Obj_Entry *defobj; 3776 const Objlist_Entry *elm; 3777 SymLook req1; 3778 int res; 3779 3780 def = NULL; 3781 defobj = NULL; 3782 STAILQ_FOREACH(elm, objlist, link) { 3783 if (donelist_check(dlp, elm->obj)) 3784 continue; 3785 symlook_init_from_req(&req1, req); 3786 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3787 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3788 def = req1.sym_out; 3789 defobj = req1.defobj_out; 3790 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3791 break; 3792 } 3793 } 3794 } 3795 if (def != NULL) { 3796 req->sym_out = def; 3797 req->defobj_out = defobj; 3798 return (0); 3799 } 3800 return (ESRCH); 3801} 3802 3803/* 3804 * Search the chain of DAGS cointed to by the given Needed_Entry 3805 * for a symbol of the given name. Each DAG is scanned completely 3806 * before advancing to the next one. Returns a pointer to the symbol, 3807 * or NULL if no definition was found. 3808 */ 3809static int 3810symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3811{ 3812 const Elf_Sym *def; 3813 const Needed_Entry *n; 3814 const Obj_Entry *defobj; 3815 SymLook req1; 3816 int res; 3817 3818 def = NULL; 3819 defobj = NULL; 3820 symlook_init_from_req(&req1, req); 3821 for (n = needed; n != NULL; n = n->next) { 3822 if (n->obj == NULL || 3823 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3824 continue; 3825 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3826 def = req1.sym_out; 3827 defobj = req1.defobj_out; 3828 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3829 break; 3830 } 3831 } 3832 if (def != NULL) { 3833 req->sym_out = def; 3834 req->defobj_out = defobj; 3835 return (0); 3836 } 3837 return (ESRCH); 3838} 3839 3840/* 3841 * Search the symbol table of a single shared object for a symbol of 3842 * the given name and version, if requested. Returns a pointer to the 3843 * symbol, or NULL if no definition was found. If the object is 3844 * filter, return filtered symbol from filtee. 3845 * 3846 * The symbol's hash value is passed in for efficiency reasons; that 3847 * eliminates many recomputations of the hash value. 3848 */ 3849int 3850symlook_obj(SymLook *req, const Obj_Entry *obj) 3851{ 3852 DoneList donelist; 3853 SymLook req1; 3854 int flags, res, mres; 3855 3856 /* 3857 * If there is at least one valid hash at this point, we prefer to 3858 * use the faster GNU version if available. 3859 */ 3860 if (obj->valid_hash_gnu) 3861 mres = symlook_obj1_gnu(req, obj); 3862 else if (obj->valid_hash_sysv) 3863 mres = symlook_obj1_sysv(req, obj); 3864 else 3865 return (EINVAL); 3866 3867 if (mres == 0) { 3868 if (obj->needed_filtees != NULL) { 3869 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3870 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3871 donelist_init(&donelist); 3872 symlook_init_from_req(&req1, req); 3873 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3874 if (res == 0) { 3875 req->sym_out = req1.sym_out; 3876 req->defobj_out = req1.defobj_out; 3877 } 3878 return (res); 3879 } 3880 if (obj->needed_aux_filtees != NULL) { 3881 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3882 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3883 donelist_init(&donelist); 3884 symlook_init_from_req(&req1, req); 3885 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3886 if (res == 0) { 3887 req->sym_out = req1.sym_out; 3888 req->defobj_out = req1.defobj_out; 3889 return (res); 3890 } 3891 } 3892 } 3893 return (mres); 3894} 3895 3896/* Symbol match routine common to both hash functions */ 3897static bool 3898matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3899 const unsigned long symnum) 3900{ 3901 Elf_Versym verndx; 3902 const Elf_Sym *symp; 3903 const char *strp; 3904 3905 symp = obj->symtab + symnum; 3906 strp = obj->strtab + symp->st_name; 3907 3908 switch (ELF_ST_TYPE(symp->st_info)) { 3909 case STT_FUNC: 3910 case STT_NOTYPE: 3911 case STT_OBJECT: 3912 case STT_COMMON: 3913 case STT_GNU_IFUNC: 3914 if (symp->st_value == 0) 3915 return (false); 3916 /* fallthrough */ 3917 case STT_TLS: 3918 if (symp->st_shndx != SHN_UNDEF) 3919 break; 3920#ifndef __mips__ 3921 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3922 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3923 break; 3924 /* fallthrough */ 3925#endif 3926 default: 3927 return (false); 3928 } 3929 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3930 return (false); 3931 3932 if (req->ventry == NULL) { 3933 if (obj->versyms != NULL) { 3934 verndx = VER_NDX(obj->versyms[symnum]); 3935 if (verndx > obj->vernum) { 3936 _rtld_error( 3937 "%s: symbol %s references wrong version %d", 3938 obj->path, obj->strtab + symnum, verndx); 3939 return (false); 3940 } 3941 /* 3942 * If we are not called from dlsym (i.e. this 3943 * is a normal relocation from unversioned 3944 * binary), accept the symbol immediately if 3945 * it happens to have first version after this 3946 * shared object became versioned. Otherwise, 3947 * if symbol is versioned and not hidden, 3948 * remember it. If it is the only symbol with 3949 * this name exported by the shared object, it 3950 * will be returned as a match by the calling 3951 * function. If symbol is global (verndx < 2) 3952 * accept it unconditionally. 3953 */ 3954 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3955 verndx == VER_NDX_GIVEN) { 3956 result->sym_out = symp; 3957 return (true); 3958 } 3959 else if (verndx >= VER_NDX_GIVEN) { 3960 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3961 == 0) { 3962 if (result->vsymp == NULL) 3963 result->vsymp = symp; 3964 result->vcount++; 3965 } 3966 return (false); 3967 } 3968 } 3969 result->sym_out = symp; 3970 return (true); 3971 } 3972 if (obj->versyms == NULL) { 3973 if (object_match_name(obj, req->ventry->name)) { 3974 _rtld_error("%s: object %s should provide version %s " 3975 "for symbol %s", obj_rtld.path, obj->path, 3976 req->ventry->name, obj->strtab + symnum); 3977 return (false); 3978 } 3979 } else { 3980 verndx = VER_NDX(obj->versyms[symnum]); 3981 if (verndx > obj->vernum) { 3982 _rtld_error("%s: symbol %s references wrong version %d", 3983 obj->path, obj->strtab + symnum, verndx); 3984 return (false); 3985 } 3986 if (obj->vertab[verndx].hash != req->ventry->hash || 3987 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3988 /* 3989 * Version does not match. Look if this is a 3990 * global symbol and if it is not hidden. If 3991 * global symbol (verndx < 2) is available, 3992 * use it. Do not return symbol if we are 3993 * called by dlvsym, because dlvsym looks for 3994 * a specific version and default one is not 3995 * what dlvsym wants. 3996 */ 3997 if ((req->flags & SYMLOOK_DLSYM) || 3998 (verndx >= VER_NDX_GIVEN) || 3999 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4000 return (false); 4001 } 4002 } 4003 result->sym_out = symp; 4004 return (true); 4005} 4006 4007/* 4008 * Search for symbol using SysV hash function. 4009 * obj->buckets is known not to be NULL at this point; the test for this was 4010 * performed with the obj->valid_hash_sysv assignment. 4011 */ 4012static int 4013symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4014{ 4015 unsigned long symnum; 4016 Sym_Match_Result matchres; 4017 4018 matchres.sym_out = NULL; 4019 matchres.vsymp = NULL; 4020 matchres.vcount = 0; 4021 4022 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4023 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4024 if (symnum >= obj->nchains) 4025 return (ESRCH); /* Bad object */ 4026 4027 if (matched_symbol(req, obj, &matchres, symnum)) { 4028 req->sym_out = matchres.sym_out; 4029 req->defobj_out = obj; 4030 return (0); 4031 } 4032 } 4033 if (matchres.vcount == 1) { 4034 req->sym_out = matchres.vsymp; 4035 req->defobj_out = obj; 4036 return (0); 4037 } 4038 return (ESRCH); 4039} 4040 4041/* Search for symbol using GNU hash function */ 4042static int 4043symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4044{ 4045 Elf_Addr bloom_word; 4046 const Elf32_Word *hashval; 4047 Elf32_Word bucket; 4048 Sym_Match_Result matchres; 4049 unsigned int h1, h2; 4050 unsigned long symnum; 4051 4052 matchres.sym_out = NULL; 4053 matchres.vsymp = NULL; 4054 matchres.vcount = 0; 4055 4056 /* Pick right bitmask word from Bloom filter array */ 4057 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4058 obj->maskwords_bm_gnu]; 4059 4060 /* Calculate modulus word size of gnu hash and its derivative */ 4061 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4062 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4063 4064 /* Filter out the "definitely not in set" queries */ 4065 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4066 return (ESRCH); 4067 4068 /* Locate hash chain and corresponding value element*/ 4069 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4070 if (bucket == 0) 4071 return (ESRCH); 4072 hashval = &obj->chain_zero_gnu[bucket]; 4073 do { 4074 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4075 symnum = hashval - obj->chain_zero_gnu; 4076 if (matched_symbol(req, obj, &matchres, symnum)) { 4077 req->sym_out = matchres.sym_out; 4078 req->defobj_out = obj; 4079 return (0); 4080 } 4081 } 4082 } while ((*hashval++ & 1) == 0); 4083 if (matchres.vcount == 1) { 4084 req->sym_out = matchres.vsymp; 4085 req->defobj_out = obj; 4086 return (0); 4087 } 4088 return (ESRCH); 4089} 4090 4091static void 4092trace_loaded_objects(Obj_Entry *obj) 4093{ 4094 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4095 int c; 4096 4097 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4098 main_local = ""; 4099 4100 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4101 fmt1 = "\t%o => %p (%x)\n"; 4102 4103 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4104 fmt2 = "\t%o (%x)\n"; 4105 4106 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4107 4108 for (; obj; obj = obj->next) { 4109 Needed_Entry *needed; 4110 char *name, *path; 4111 bool is_lib; 4112 4113 if (list_containers && obj->needed != NULL) 4114 rtld_printf("%s:\n", obj->path); 4115 for (needed = obj->needed; needed; needed = needed->next) { 4116 if (needed->obj != NULL) { 4117 if (needed->obj->traced && !list_containers) 4118 continue; 4119 needed->obj->traced = true; 4120 path = needed->obj->path; 4121 } else 4122 path = "not found"; 4123 4124 name = (char *)obj->strtab + needed->name; 4125 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4126 4127 fmt = is_lib ? fmt1 : fmt2; 4128 while ((c = *fmt++) != '\0') { 4129 switch (c) { 4130 default: 4131 rtld_putchar(c); 4132 continue; 4133 case '\\': 4134 switch (c = *fmt) { 4135 case '\0': 4136 continue; 4137 case 'n': 4138 rtld_putchar('\n'); 4139 break; 4140 case 't': 4141 rtld_putchar('\t'); 4142 break; 4143 } 4144 break; 4145 case '%': 4146 switch (c = *fmt) { 4147 case '\0': 4148 continue; 4149 case '%': 4150 default: 4151 rtld_putchar(c); 4152 break; 4153 case 'A': 4154 rtld_putstr(main_local); 4155 break; 4156 case 'a': 4157 rtld_putstr(obj_main->path); 4158 break; 4159 case 'o': 4160 rtld_putstr(name); 4161 break; 4162#if 0 4163 case 'm': 4164 rtld_printf("%d", sodp->sod_major); 4165 break; 4166 case 'n': 4167 rtld_printf("%d", sodp->sod_minor); 4168 break; 4169#endif 4170 case 'p': 4171 rtld_putstr(path); 4172 break; 4173 case 'x': 4174 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4175 0); 4176 break; 4177 } 4178 break; 4179 } 4180 ++fmt; 4181 } 4182 } 4183 } 4184} 4185 4186/* 4187 * Unload a dlopened object and its dependencies from memory and from 4188 * our data structures. It is assumed that the DAG rooted in the 4189 * object has already been unreferenced, and that the object has a 4190 * reference count of 0. 4191 */ 4192static void 4193unload_object(Obj_Entry *root) 4194{ 4195 Obj_Entry *obj; 4196 Obj_Entry **linkp; 4197 4198 assert(root->refcount == 0); 4199 4200 /* 4201 * Pass over the DAG removing unreferenced objects from 4202 * appropriate lists. 4203 */ 4204 unlink_object(root); 4205 4206 /* Unmap all objects that are no longer referenced. */ 4207 linkp = &obj_list->next; 4208 while ((obj = *linkp) != NULL) { 4209 if (obj->refcount == 0) { 4210 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4211 obj->path); 4212 dbg("unloading \"%s\"", obj->path); 4213 unload_filtees(root); 4214 munmap(obj->mapbase, obj->mapsize); 4215 linkmap_delete(obj); 4216 *linkp = obj->next; 4217 obj_count--; 4218 obj_free(obj); 4219 } else 4220 linkp = &obj->next; 4221 } 4222 obj_tail = linkp; 4223} 4224 4225static void 4226unlink_object(Obj_Entry *root) 4227{ 4228 Objlist_Entry *elm; 4229 4230 if (root->refcount == 0) { 4231 /* Remove the object from the RTLD_GLOBAL list. */ 4232 objlist_remove(&list_global, root); 4233 4234 /* Remove the object from all objects' DAG lists. */ 4235 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4236 objlist_remove(&elm->obj->dldags, root); 4237 if (elm->obj != root) 4238 unlink_object(elm->obj); 4239 } 4240 } 4241} 4242 4243static void 4244ref_dag(Obj_Entry *root) 4245{ 4246 Objlist_Entry *elm; 4247 4248 assert(root->dag_inited); 4249 STAILQ_FOREACH(elm, &root->dagmembers, link) 4250 elm->obj->refcount++; 4251} 4252 4253static void 4254unref_dag(Obj_Entry *root) 4255{ 4256 Objlist_Entry *elm; 4257 4258 assert(root->dag_inited); 4259 STAILQ_FOREACH(elm, &root->dagmembers, link) 4260 elm->obj->refcount--; 4261} 4262 4263/* 4264 * Common code for MD __tls_get_addr(). 4265 */ 4266static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4267static void * 4268tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4269{ 4270 Elf_Addr *newdtv, *dtv; 4271 RtldLockState lockstate; 4272 int to_copy; 4273 4274 dtv = *dtvp; 4275 /* Check dtv generation in case new modules have arrived */ 4276 if (dtv[0] != tls_dtv_generation) { 4277 wlock_acquire(rtld_bind_lock, &lockstate); 4278 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4279 to_copy = dtv[1]; 4280 if (to_copy > tls_max_index) 4281 to_copy = tls_max_index; 4282 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4283 newdtv[0] = tls_dtv_generation; 4284 newdtv[1] = tls_max_index; 4285 free(dtv); 4286 lock_release(rtld_bind_lock, &lockstate); 4287 dtv = *dtvp = newdtv; 4288 } 4289 4290 /* Dynamically allocate module TLS if necessary */ 4291 if (dtv[index + 1] == 0) { 4292 /* Signal safe, wlock will block out signals. */ 4293 wlock_acquire(rtld_bind_lock, &lockstate); 4294 if (!dtv[index + 1]) 4295 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4296 lock_release(rtld_bind_lock, &lockstate); 4297 } 4298 return ((void *)(dtv[index + 1] + offset)); 4299} 4300 4301void * 4302tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4303{ 4304 Elf_Addr *dtv; 4305 4306 dtv = *dtvp; 4307 /* Check dtv generation in case new modules have arrived */ 4308 if (__predict_true(dtv[0] == tls_dtv_generation && 4309 dtv[index + 1] != 0)) 4310 return ((void *)(dtv[index + 1] + offset)); 4311 return (tls_get_addr_slow(dtvp, index, offset)); 4312} 4313 4314#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4315 4316/* 4317 * Allocate Static TLS using the Variant I method. 4318 */ 4319void * 4320allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4321{ 4322 Obj_Entry *obj; 4323 char *tcb; 4324 Elf_Addr **tls; 4325 Elf_Addr *dtv; 4326 Elf_Addr addr; 4327 int i; 4328 4329 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4330 return (oldtcb); 4331 4332 assert(tcbsize >= TLS_TCB_SIZE); 4333 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4334 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4335 4336 if (oldtcb != NULL) { 4337 memcpy(tls, oldtcb, tls_static_space); 4338 free(oldtcb); 4339 4340 /* Adjust the DTV. */ 4341 dtv = tls[0]; 4342 for (i = 0; i < dtv[1]; i++) { 4343 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4344 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4345 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4346 } 4347 } 4348 } else { 4349 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4350 tls[0] = dtv; 4351 dtv[0] = tls_dtv_generation; 4352 dtv[1] = tls_max_index; 4353 4354 for (obj = objs; obj; obj = obj->next) { 4355 if (obj->tlsoffset > 0) { 4356 addr = (Elf_Addr)tls + obj->tlsoffset; 4357 if (obj->tlsinitsize > 0) 4358 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4359 if (obj->tlssize > obj->tlsinitsize) 4360 memset((void*) (addr + obj->tlsinitsize), 0, 4361 obj->tlssize - obj->tlsinitsize); 4362 dtv[obj->tlsindex + 1] = addr; 4363 } 4364 } 4365 } 4366 4367 return (tcb); 4368} 4369 4370void 4371free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4372{ 4373 Elf_Addr *dtv; 4374 Elf_Addr tlsstart, tlsend; 4375 int dtvsize, i; 4376 4377 assert(tcbsize >= TLS_TCB_SIZE); 4378 4379 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4380 tlsend = tlsstart + tls_static_space; 4381 4382 dtv = *(Elf_Addr **)tlsstart; 4383 dtvsize = dtv[1]; 4384 for (i = 0; i < dtvsize; i++) { 4385 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4386 free((void*)dtv[i+2]); 4387 } 4388 } 4389 free(dtv); 4390 free(tcb); 4391} 4392 4393#endif 4394 4395#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4396 4397/* 4398 * Allocate Static TLS using the Variant II method. 4399 */ 4400void * 4401allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4402{ 4403 Obj_Entry *obj; 4404 size_t size, ralign; 4405 char *tls; 4406 Elf_Addr *dtv, *olddtv; 4407 Elf_Addr segbase, oldsegbase, addr; 4408 int i; 4409 4410 ralign = tcbalign; 4411 if (tls_static_max_align > ralign) 4412 ralign = tls_static_max_align; 4413 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4414 4415 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4416 tls = malloc_aligned(size, ralign); 4417 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4418 4419 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4420 ((Elf_Addr*)segbase)[0] = segbase; 4421 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4422 4423 dtv[0] = tls_dtv_generation; 4424 dtv[1] = tls_max_index; 4425 4426 if (oldtls) { 4427 /* 4428 * Copy the static TLS block over whole. 4429 */ 4430 oldsegbase = (Elf_Addr) oldtls; 4431 memcpy((void *)(segbase - tls_static_space), 4432 (const void *)(oldsegbase - tls_static_space), 4433 tls_static_space); 4434 4435 /* 4436 * If any dynamic TLS blocks have been created tls_get_addr(), 4437 * move them over. 4438 */ 4439 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4440 for (i = 0; i < olddtv[1]; i++) { 4441 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4442 dtv[i+2] = olddtv[i+2]; 4443 olddtv[i+2] = 0; 4444 } 4445 } 4446 4447 /* 4448 * We assume that this block was the one we created with 4449 * allocate_initial_tls(). 4450 */ 4451 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4452 } else { 4453 for (obj = objs; obj; obj = obj->next) { 4454 if (obj->tlsoffset) { 4455 addr = segbase - obj->tlsoffset; 4456 memset((void*) (addr + obj->tlsinitsize), 4457 0, obj->tlssize - obj->tlsinitsize); 4458 if (obj->tlsinit) 4459 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4460 dtv[obj->tlsindex + 1] = addr; 4461 } 4462 } 4463 } 4464 4465 return (void*) segbase; 4466} 4467 4468void 4469free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4470{ 4471 Elf_Addr* dtv; 4472 size_t size, ralign; 4473 int dtvsize, i; 4474 Elf_Addr tlsstart, tlsend; 4475 4476 /* 4477 * Figure out the size of the initial TLS block so that we can 4478 * find stuff which ___tls_get_addr() allocated dynamically. 4479 */ 4480 ralign = tcbalign; 4481 if (tls_static_max_align > ralign) 4482 ralign = tls_static_max_align; 4483 size = round(tls_static_space, ralign); 4484 4485 dtv = ((Elf_Addr**)tls)[1]; 4486 dtvsize = dtv[1]; 4487 tlsend = (Elf_Addr) tls; 4488 tlsstart = tlsend - size; 4489 for (i = 0; i < dtvsize; i++) { 4490 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4491 free_aligned((void *)dtv[i + 2]); 4492 } 4493 } 4494 4495 free_aligned((void *)tlsstart); 4496 free((void*) dtv); 4497} 4498 4499#endif 4500 4501/* 4502 * Allocate TLS block for module with given index. 4503 */ 4504void * 4505allocate_module_tls(int index) 4506{ 4507 Obj_Entry* obj; 4508 char* p; 4509 4510 for (obj = obj_list; obj; obj = obj->next) { 4511 if (obj->tlsindex == index) 4512 break; 4513 } 4514 if (!obj) { 4515 _rtld_error("Can't find module with TLS index %d", index); 4516 rtld_die(); 4517 } 4518 4519 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4520 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4521 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4522 4523 return p; 4524} 4525 4526bool 4527allocate_tls_offset(Obj_Entry *obj) 4528{ 4529 size_t off; 4530 4531 if (obj->tls_done) 4532 return true; 4533 4534 if (obj->tlssize == 0) { 4535 obj->tls_done = true; 4536 return true; 4537 } 4538 4539 if (obj->tlsindex == 1) 4540 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4541 else 4542 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4543 obj->tlssize, obj->tlsalign); 4544 4545 /* 4546 * If we have already fixed the size of the static TLS block, we 4547 * must stay within that size. When allocating the static TLS, we 4548 * leave a small amount of space spare to be used for dynamically 4549 * loading modules which use static TLS. 4550 */ 4551 if (tls_static_space != 0) { 4552 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4553 return false; 4554 } else if (obj->tlsalign > tls_static_max_align) { 4555 tls_static_max_align = obj->tlsalign; 4556 } 4557 4558 tls_last_offset = obj->tlsoffset = off; 4559 tls_last_size = obj->tlssize; 4560 obj->tls_done = true; 4561 4562 return true; 4563} 4564 4565void 4566free_tls_offset(Obj_Entry *obj) 4567{ 4568 4569 /* 4570 * If we were the last thing to allocate out of the static TLS 4571 * block, we give our space back to the 'allocator'. This is a 4572 * simplistic workaround to allow libGL.so.1 to be loaded and 4573 * unloaded multiple times. 4574 */ 4575 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4576 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4577 tls_last_offset -= obj->tlssize; 4578 tls_last_size = 0; 4579 } 4580} 4581 4582void * 4583_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4584{ 4585 void *ret; 4586 RtldLockState lockstate; 4587 4588 wlock_acquire(rtld_bind_lock, &lockstate); 4589 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4590 lock_release(rtld_bind_lock, &lockstate); 4591 return (ret); 4592} 4593 4594void 4595_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4596{ 4597 RtldLockState lockstate; 4598 4599 wlock_acquire(rtld_bind_lock, &lockstate); 4600 free_tls(tcb, tcbsize, tcbalign); 4601 lock_release(rtld_bind_lock, &lockstate); 4602} 4603 4604static void 4605object_add_name(Obj_Entry *obj, const char *name) 4606{ 4607 Name_Entry *entry; 4608 size_t len; 4609 4610 len = strlen(name); 4611 entry = malloc(sizeof(Name_Entry) + len); 4612 4613 if (entry != NULL) { 4614 strcpy(entry->name, name); 4615 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4616 } 4617} 4618 4619static int 4620object_match_name(const Obj_Entry *obj, const char *name) 4621{ 4622 Name_Entry *entry; 4623 4624 STAILQ_FOREACH(entry, &obj->names, link) { 4625 if (strcmp(name, entry->name) == 0) 4626 return (1); 4627 } 4628 return (0); 4629} 4630 4631static Obj_Entry * 4632locate_dependency(const Obj_Entry *obj, const char *name) 4633{ 4634 const Objlist_Entry *entry; 4635 const Needed_Entry *needed; 4636 4637 STAILQ_FOREACH(entry, &list_main, link) { 4638 if (object_match_name(entry->obj, name)) 4639 return entry->obj; 4640 } 4641 4642 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4643 if (strcmp(obj->strtab + needed->name, name) == 0 || 4644 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4645 /* 4646 * If there is DT_NEEDED for the name we are looking for, 4647 * we are all set. Note that object might not be found if 4648 * dependency was not loaded yet, so the function can 4649 * return NULL here. This is expected and handled 4650 * properly by the caller. 4651 */ 4652 return (needed->obj); 4653 } 4654 } 4655 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4656 obj->path, name); 4657 rtld_die(); 4658} 4659 4660static int 4661check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4662 const Elf_Vernaux *vna) 4663{ 4664 const Elf_Verdef *vd; 4665 const char *vername; 4666 4667 vername = refobj->strtab + vna->vna_name; 4668 vd = depobj->verdef; 4669 if (vd == NULL) { 4670 _rtld_error("%s: version %s required by %s not defined", 4671 depobj->path, vername, refobj->path); 4672 return (-1); 4673 } 4674 for (;;) { 4675 if (vd->vd_version != VER_DEF_CURRENT) { 4676 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4677 depobj->path, vd->vd_version); 4678 return (-1); 4679 } 4680 if (vna->vna_hash == vd->vd_hash) { 4681 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4682 ((char *)vd + vd->vd_aux); 4683 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4684 return (0); 4685 } 4686 if (vd->vd_next == 0) 4687 break; 4688 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4689 } 4690 if (vna->vna_flags & VER_FLG_WEAK) 4691 return (0); 4692 _rtld_error("%s: version %s required by %s not found", 4693 depobj->path, vername, refobj->path); 4694 return (-1); 4695} 4696 4697static int 4698rtld_verify_object_versions(Obj_Entry *obj) 4699{ 4700 const Elf_Verneed *vn; 4701 const Elf_Verdef *vd; 4702 const Elf_Verdaux *vda; 4703 const Elf_Vernaux *vna; 4704 const Obj_Entry *depobj; 4705 int maxvernum, vernum; 4706 4707 if (obj->ver_checked) 4708 return (0); 4709 obj->ver_checked = true; 4710 4711 maxvernum = 0; 4712 /* 4713 * Walk over defined and required version records and figure out 4714 * max index used by any of them. Do very basic sanity checking 4715 * while there. 4716 */ 4717 vn = obj->verneed; 4718 while (vn != NULL) { 4719 if (vn->vn_version != VER_NEED_CURRENT) { 4720 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4721 obj->path, vn->vn_version); 4722 return (-1); 4723 } 4724 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4725 for (;;) { 4726 vernum = VER_NEED_IDX(vna->vna_other); 4727 if (vernum > maxvernum) 4728 maxvernum = vernum; 4729 if (vna->vna_next == 0) 4730 break; 4731 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4732 } 4733 if (vn->vn_next == 0) 4734 break; 4735 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4736 } 4737 4738 vd = obj->verdef; 4739 while (vd != NULL) { 4740 if (vd->vd_version != VER_DEF_CURRENT) { 4741 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4742 obj->path, vd->vd_version); 4743 return (-1); 4744 } 4745 vernum = VER_DEF_IDX(vd->vd_ndx); 4746 if (vernum > maxvernum) 4747 maxvernum = vernum; 4748 if (vd->vd_next == 0) 4749 break; 4750 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4751 } 4752 4753 if (maxvernum == 0) 4754 return (0); 4755 4756 /* 4757 * Store version information in array indexable by version index. 4758 * Verify that object version requirements are satisfied along the 4759 * way. 4760 */ 4761 obj->vernum = maxvernum + 1; 4762 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4763 4764 vd = obj->verdef; 4765 while (vd != NULL) { 4766 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4767 vernum = VER_DEF_IDX(vd->vd_ndx); 4768 assert(vernum <= maxvernum); 4769 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4770 obj->vertab[vernum].hash = vd->vd_hash; 4771 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4772 obj->vertab[vernum].file = NULL; 4773 obj->vertab[vernum].flags = 0; 4774 } 4775 if (vd->vd_next == 0) 4776 break; 4777 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4778 } 4779 4780 vn = obj->verneed; 4781 while (vn != NULL) { 4782 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4783 if (depobj == NULL) 4784 return (-1); 4785 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4786 for (;;) { 4787 if (check_object_provided_version(obj, depobj, vna)) 4788 return (-1); 4789 vernum = VER_NEED_IDX(vna->vna_other); 4790 assert(vernum <= maxvernum); 4791 obj->vertab[vernum].hash = vna->vna_hash; 4792 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4793 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4794 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4795 VER_INFO_HIDDEN : 0; 4796 if (vna->vna_next == 0) 4797 break; 4798 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4799 } 4800 if (vn->vn_next == 0) 4801 break; 4802 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4803 } 4804 return 0; 4805} 4806 4807static int 4808rtld_verify_versions(const Objlist *objlist) 4809{ 4810 Objlist_Entry *entry; 4811 int rc; 4812 4813 rc = 0; 4814 STAILQ_FOREACH(entry, objlist, link) { 4815 /* 4816 * Skip dummy objects or objects that have their version requirements 4817 * already checked. 4818 */ 4819 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4820 continue; 4821 if (rtld_verify_object_versions(entry->obj) == -1) { 4822 rc = -1; 4823 if (ld_tracing == NULL) 4824 break; 4825 } 4826 } 4827 if (rc == 0 || ld_tracing != NULL) 4828 rc = rtld_verify_object_versions(&obj_rtld); 4829 return rc; 4830} 4831 4832const Ver_Entry * 4833fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4834{ 4835 Elf_Versym vernum; 4836 4837 if (obj->vertab) { 4838 vernum = VER_NDX(obj->versyms[symnum]); 4839 if (vernum >= obj->vernum) { 4840 _rtld_error("%s: symbol %s has wrong verneed value %d", 4841 obj->path, obj->strtab + symnum, vernum); 4842 } else if (obj->vertab[vernum].hash != 0) { 4843 return &obj->vertab[vernum]; 4844 } 4845 } 4846 return NULL; 4847} 4848 4849int 4850_rtld_get_stack_prot(void) 4851{ 4852 4853 return (stack_prot); 4854} 4855 4856int 4857_rtld_is_dlopened(void *arg) 4858{ 4859 Obj_Entry *obj; 4860 RtldLockState lockstate; 4861 int res; 4862 4863 rlock_acquire(rtld_bind_lock, &lockstate); 4864 obj = dlcheck(arg); 4865 if (obj == NULL) 4866 obj = obj_from_addr(arg); 4867 if (obj == NULL) { 4868 _rtld_error("No shared object contains address"); 4869 lock_release(rtld_bind_lock, &lockstate); 4870 return (-1); 4871 } 4872 res = obj->dlopened ? 1 : 0; 4873 lock_release(rtld_bind_lock, &lockstate); 4874 return (res); 4875} 4876 4877static void 4878map_stacks_exec(RtldLockState *lockstate) 4879{ 4880 void (*thr_map_stacks_exec)(void); 4881 4882 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4883 return; 4884 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4885 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4886 if (thr_map_stacks_exec != NULL) { 4887 stack_prot |= PROT_EXEC; 4888 thr_map_stacks_exec(); 4889 } 4890} 4891 4892void 4893symlook_init(SymLook *dst, const char *name) 4894{ 4895 4896 bzero(dst, sizeof(*dst)); 4897 dst->name = name; 4898 dst->hash = elf_hash(name); 4899 dst->hash_gnu = gnu_hash(name); 4900} 4901 4902static void 4903symlook_init_from_req(SymLook *dst, const SymLook *src) 4904{ 4905 4906 dst->name = src->name; 4907 dst->hash = src->hash; 4908 dst->hash_gnu = src->hash_gnu; 4909 dst->ventry = src->ventry; 4910 dst->flags = src->flags; 4911 dst->defobj_out = NULL; 4912 dst->sym_out = NULL; 4913 dst->lockstate = src->lockstate; 4914} 4915 4916/* 4917 * Overrides for libc_pic-provided functions. 4918 */ 4919 4920int 4921__getosreldate(void) 4922{ 4923 size_t len; 4924 int oid[2]; 4925 int error, osrel; 4926 4927 if (osreldate != 0) 4928 return (osreldate); 4929 4930 oid[0] = CTL_KERN; 4931 oid[1] = KERN_OSRELDATE; 4932 osrel = 0; 4933 len = sizeof(osrel); 4934 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4935 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4936 osreldate = osrel; 4937 return (osreldate); 4938} 4939 4940void 4941exit(int status) 4942{ 4943 4944 _exit(status); 4945} 4946 4947void (*__cleanup)(void); 4948int __isthreaded = 0; 4949int _thread_autoinit_dummy_decl = 1; 4950 4951/* 4952 * No unresolved symbols for rtld. 4953 */ 4954void 4955__pthread_cxa_finalize(struct dl_phdr_info *a) 4956{ 4957} 4958 4959void 4960__stack_chk_fail(void) 4961{ 4962 4963 _rtld_error("stack overflow detected; terminated"); 4964 rtld_die(); 4965} 4966__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4967 4968void 4969__chk_fail(void) 4970{ 4971 4972 _rtld_error("buffer overflow detected; terminated"); 4973 rtld_die(); 4974} 4975 4976const char * 4977rtld_strerror(int errnum) 4978{ 4979 4980 if (errnum < 0 || errnum >= sys_nerr) 4981 return ("Unknown error"); 4982 return (sys_errlist[errnum]); 4983} 4984