rtld.c revision 296939
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 296939 2016-03-16 15:34:16Z kib $ 29 */ 30 31/* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37#include <sys/param.h> 38#include <sys/mount.h> 39#include <sys/mman.h> 40#include <sys/stat.h> 41#include <sys/sysctl.h> 42#include <sys/uio.h> 43#include <sys/utsname.h> 44#include <sys/ktrace.h> 45 46#include <dlfcn.h> 47#include <err.h> 48#include <errno.h> 49#include <fcntl.h> 50#include <stdarg.h> 51#include <stdio.h> 52#include <stdlib.h> 53#include <string.h> 54#include <unistd.h> 55 56#include "debug.h" 57#include "rtld.h" 58#include "libmap.h" 59#include "rtld_tls.h" 60#include "rtld_printf.h" 61#include "notes.h" 62 63#ifndef COMPAT_32BIT 64#define PATH_RTLD "/libexec/ld-elf.so.1" 65#else 66#define PATH_RTLD "/libexec/ld-elf32.so.1" 67#endif 68 69/* Types. */ 70typedef void (*func_ptr_type)(); 71typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73/* 74 * Function declarations. 75 */ 76static const char *basename(const char *); 77static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 78 const Elf_Dyn **, const Elf_Dyn **); 79static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 80 const Elf_Dyn *); 81static void digest_dynamic(Obj_Entry *, int); 82static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 83static Obj_Entry *dlcheck(void *); 84static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 85 int lo_flags, int mode, RtldLockState *lockstate); 86static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 87static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 88static bool donelist_check(DoneList *, const Obj_Entry *); 89static void errmsg_restore(char *); 90static char *errmsg_save(void); 91static void *fill_search_info(const char *, size_t, void *); 92static char *find_library(const char *, const Obj_Entry *); 93static const char *gethints(bool); 94static void init_dag(Obj_Entry *); 95static void init_pagesizes(Elf_Auxinfo **aux_info); 96static void init_rtld(caddr_t, Elf_Auxinfo **); 97static void initlist_add_neededs(Needed_Entry *, Objlist *); 98static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 99static void linkmap_add(Obj_Entry *); 100static void linkmap_delete(Obj_Entry *); 101static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 102static void unload_filtees(Obj_Entry *); 103static int load_needed_objects(Obj_Entry *, int); 104static int load_preload_objects(void); 105static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 106static void map_stacks_exec(RtldLockState *); 107static Obj_Entry *obj_from_addr(const void *); 108static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 109static void objlist_call_init(Objlist *, RtldLockState *); 110static void objlist_clear(Objlist *); 111static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 112static void objlist_init(Objlist *); 113static void objlist_push_head(Objlist *, Obj_Entry *); 114static void objlist_push_tail(Objlist *, Obj_Entry *); 115static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 116static void objlist_remove(Objlist *, Obj_Entry *); 117static void *path_enumerate(const char *, path_enum_proc, void *); 118static int relocate_object_dag(Obj_Entry *root, bool bind_now, 119 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 120static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 121 int flags, RtldLockState *lockstate); 122static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 123 RtldLockState *); 124static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 125 int flags, RtldLockState *lockstate); 126static int rtld_dirname(const char *, char *); 127static int rtld_dirname_abs(const char *, char *); 128static void *rtld_dlopen(const char *name, int fd, int mode); 129static void rtld_exit(void); 130static char *search_library_path(const char *, const char *); 131static const void **get_program_var_addr(const char *, RtldLockState *); 132static void set_program_var(const char *, const void *); 133static int symlook_default(SymLook *, const Obj_Entry *refobj); 134static int symlook_global(SymLook *, DoneList *); 135static void symlook_init_from_req(SymLook *, const SymLook *); 136static int symlook_list(SymLook *, const Objlist *, DoneList *); 137static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 138static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 139static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 140static void trace_loaded_objects(Obj_Entry *); 141static void unlink_object(Obj_Entry *); 142static void unload_object(Obj_Entry *); 143static void unref_dag(Obj_Entry *); 144static void ref_dag(Obj_Entry *); 145static char *origin_subst_one(Obj_Entry *, char *, const char *, 146 const char *, bool); 147static char *origin_subst(Obj_Entry *, char *); 148static bool obj_resolve_origin(Obj_Entry *obj); 149static void preinit_main(void); 150static int rtld_verify_versions(const Objlist *); 151static int rtld_verify_object_versions(Obj_Entry *); 152static void object_add_name(Obj_Entry *, const char *); 153static int object_match_name(const Obj_Entry *, const char *); 154static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 155static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 156 struct dl_phdr_info *phdr_info); 157static uint32_t gnu_hash(const char *); 158static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 159 const unsigned long); 160 161void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 162void _r_debug_postinit(struct link_map *) __noinline __exported; 163 164/* 165 * Data declarations. 166 */ 167static char *error_message; /* Message for dlerror(), or NULL */ 168struct r_debug r_debug __exported; /* for GDB; */ 169static bool libmap_disable; /* Disable libmap */ 170static bool ld_loadfltr; /* Immediate filters processing */ 171static char *libmap_override; /* Maps to use in addition to libmap.conf */ 172static bool trust; /* False for setuid and setgid programs */ 173static bool dangerous_ld_env; /* True if environment variables have been 174 used to affect the libraries loaded */ 175static char *ld_bind_now; /* Environment variable for immediate binding */ 176static char *ld_debug; /* Environment variable for debugging */ 177static char *ld_library_path; /* Environment variable for search path */ 178static char *ld_preload; /* Environment variable for libraries to 179 load first */ 180static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 181static char *ld_tracing; /* Called from ldd to print libs */ 182static char *ld_utrace; /* Use utrace() to log events. */ 183static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 184static Obj_Entry *obj_main; /* The main program shared object */ 185static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 186static unsigned int obj_count; /* Number of objects in obj_list */ 187static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 188 189static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 190 STAILQ_HEAD_INITIALIZER(list_global); 191static Objlist list_main = /* Objects loaded at program startup */ 192 STAILQ_HEAD_INITIALIZER(list_main); 193static Objlist list_fini = /* Objects needing fini() calls */ 194 STAILQ_HEAD_INITIALIZER(list_fini); 195 196Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 197 198#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 199 200extern Elf_Dyn _DYNAMIC; 201#pragma weak _DYNAMIC 202#ifndef RTLD_IS_DYNAMIC 203#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 204#endif 205 206int dlclose(void *) __exported; 207char *dlerror(void) __exported; 208void *dlopen(const char *, int) __exported; 209void *fdlopen(int, int) __exported; 210void *dlsym(void *, const char *) __exported; 211dlfunc_t dlfunc(void *, const char *) __exported; 212void *dlvsym(void *, const char *, const char *) __exported; 213int dladdr(const void *, Dl_info *) __exported; 214void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 215 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 216int dlinfo(void *, int , void *) __exported; 217int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 218int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 219int _rtld_get_stack_prot(void) __exported; 220int _rtld_is_dlopened(void *) __exported; 221void _rtld_error(const char *, ...) __exported; 222 223int npagesizes, osreldate; 224size_t *pagesizes; 225 226long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 227 228static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 229static int max_stack_flags; 230 231/* 232 * Global declarations normally provided by crt1. The dynamic linker is 233 * not built with crt1, so we have to provide them ourselves. 234 */ 235char *__progname; 236char **environ; 237 238/* 239 * Used to pass argc, argv to init functions. 240 */ 241int main_argc; 242char **main_argv; 243 244/* 245 * Globals to control TLS allocation. 246 */ 247size_t tls_last_offset; /* Static TLS offset of last module */ 248size_t tls_last_size; /* Static TLS size of last module */ 249size_t tls_static_space; /* Static TLS space allocated */ 250size_t tls_static_max_align; 251int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 252int tls_max_index = 1; /* Largest module index allocated */ 253 254bool ld_library_path_rpath = false; 255 256/* 257 * Fill in a DoneList with an allocation large enough to hold all of 258 * the currently-loaded objects. Keep this as a macro since it calls 259 * alloca and we want that to occur within the scope of the caller. 260 */ 261#define donelist_init(dlp) \ 262 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 263 assert((dlp)->objs != NULL), \ 264 (dlp)->num_alloc = obj_count, \ 265 (dlp)->num_used = 0) 266 267#define UTRACE_DLOPEN_START 1 268#define UTRACE_DLOPEN_STOP 2 269#define UTRACE_DLCLOSE_START 3 270#define UTRACE_DLCLOSE_STOP 4 271#define UTRACE_LOAD_OBJECT 5 272#define UTRACE_UNLOAD_OBJECT 6 273#define UTRACE_ADD_RUNDEP 7 274#define UTRACE_PRELOAD_FINISHED 8 275#define UTRACE_INIT_CALL 9 276#define UTRACE_FINI_CALL 10 277#define UTRACE_DLSYM_START 11 278#define UTRACE_DLSYM_STOP 12 279 280struct utrace_rtld { 281 char sig[4]; /* 'RTLD' */ 282 int event; 283 void *handle; 284 void *mapbase; /* Used for 'parent' and 'init/fini' */ 285 size_t mapsize; 286 int refcnt; /* Used for 'mode' */ 287 char name[MAXPATHLEN]; 288}; 289 290#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 291 if (ld_utrace != NULL) \ 292 ld_utrace_log(e, h, mb, ms, r, n); \ 293} while (0) 294 295static void 296ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 297 int refcnt, const char *name) 298{ 299 struct utrace_rtld ut; 300 301 ut.sig[0] = 'R'; 302 ut.sig[1] = 'T'; 303 ut.sig[2] = 'L'; 304 ut.sig[3] = 'D'; 305 ut.event = event; 306 ut.handle = handle; 307 ut.mapbase = mapbase; 308 ut.mapsize = mapsize; 309 ut.refcnt = refcnt; 310 bzero(ut.name, sizeof(ut.name)); 311 if (name) 312 strlcpy(ut.name, name, sizeof(ut.name)); 313 utrace(&ut, sizeof(ut)); 314} 315 316/* 317 * Main entry point for dynamic linking. The first argument is the 318 * stack pointer. The stack is expected to be laid out as described 319 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 320 * Specifically, the stack pointer points to a word containing 321 * ARGC. Following that in the stack is a null-terminated sequence 322 * of pointers to argument strings. Then comes a null-terminated 323 * sequence of pointers to environment strings. Finally, there is a 324 * sequence of "auxiliary vector" entries. 325 * 326 * The second argument points to a place to store the dynamic linker's 327 * exit procedure pointer and the third to a place to store the main 328 * program's object. 329 * 330 * The return value is the main program's entry point. 331 */ 332func_ptr_type 333_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 334{ 335 Elf_Auxinfo *aux_info[AT_COUNT]; 336 int i; 337 int argc; 338 char **argv; 339 char **env; 340 Elf_Auxinfo *aux; 341 Elf_Auxinfo *auxp; 342 const char *argv0; 343 Objlist_Entry *entry; 344 Obj_Entry *obj; 345 Obj_Entry *preload_tail; 346 Obj_Entry *last_interposer; 347 Objlist initlist; 348 RtldLockState lockstate; 349 char *library_path_rpath; 350 int mib[2]; 351 size_t len; 352 353 /* 354 * On entry, the dynamic linker itself has not been relocated yet. 355 * Be very careful not to reference any global data until after 356 * init_rtld has returned. It is OK to reference file-scope statics 357 * and string constants, and to call static and global functions. 358 */ 359 360 /* Find the auxiliary vector on the stack. */ 361 argc = *sp++; 362 argv = (char **) sp; 363 sp += argc + 1; /* Skip over arguments and NULL terminator */ 364 env = (char **) sp; 365 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 366 ; 367 aux = (Elf_Auxinfo *) sp; 368 369 /* Digest the auxiliary vector. */ 370 for (i = 0; i < AT_COUNT; i++) 371 aux_info[i] = NULL; 372 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 373 if (auxp->a_type < AT_COUNT) 374 aux_info[auxp->a_type] = auxp; 375 } 376 377 /* Initialize and relocate ourselves. */ 378 assert(aux_info[AT_BASE] != NULL); 379 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 380 381 __progname = obj_rtld.path; 382 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 383 environ = env; 384 main_argc = argc; 385 main_argv = argv; 386 387 if (aux_info[AT_CANARY] != NULL && 388 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 389 i = aux_info[AT_CANARYLEN]->a_un.a_val; 390 if (i > sizeof(__stack_chk_guard)) 391 i = sizeof(__stack_chk_guard); 392 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 393 } else { 394 mib[0] = CTL_KERN; 395 mib[1] = KERN_ARND; 396 397 len = sizeof(__stack_chk_guard); 398 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 399 len != sizeof(__stack_chk_guard)) { 400 /* If sysctl was unsuccessful, use the "terminator canary". */ 401 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 402 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 403 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 404 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 405 } 406 } 407 408 trust = !issetugid(); 409 410 ld_bind_now = getenv(LD_ "BIND_NOW"); 411 /* 412 * If the process is tainted, then we un-set the dangerous environment 413 * variables. The process will be marked as tainted until setuid(2) 414 * is called. If any child process calls setuid(2) we do not want any 415 * future processes to honor the potentially un-safe variables. 416 */ 417 if (!trust) { 418 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 419 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 420 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 421 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 422 _rtld_error("environment corrupt; aborting"); 423 rtld_die(); 424 } 425 } 426 ld_debug = getenv(LD_ "DEBUG"); 427 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 428 libmap_override = getenv(LD_ "LIBMAP"); 429 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 430 ld_preload = getenv(LD_ "PRELOAD"); 431 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 432 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 433 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 434 if (library_path_rpath != NULL) { 435 if (library_path_rpath[0] == 'y' || 436 library_path_rpath[0] == 'Y' || 437 library_path_rpath[0] == '1') 438 ld_library_path_rpath = true; 439 else 440 ld_library_path_rpath = false; 441 } 442 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 443 (ld_library_path != NULL) || (ld_preload != NULL) || 444 (ld_elf_hints_path != NULL) || ld_loadfltr; 445 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 446 ld_utrace = getenv(LD_ "UTRACE"); 447 448 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 449 ld_elf_hints_path = _PATH_ELF_HINTS; 450 451 if (ld_debug != NULL && *ld_debug != '\0') 452 debug = 1; 453 dbg("%s is initialized, base address = %p", __progname, 454 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 455 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 456 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 457 458 dbg("initializing thread locks"); 459 lockdflt_init(); 460 461 /* 462 * Load the main program, or process its program header if it is 463 * already loaded. 464 */ 465 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 466 int fd = aux_info[AT_EXECFD]->a_un.a_val; 467 dbg("loading main program"); 468 obj_main = map_object(fd, argv0, NULL); 469 close(fd); 470 if (obj_main == NULL) 471 rtld_die(); 472 max_stack_flags = obj->stack_flags; 473 } else { /* Main program already loaded. */ 474 const Elf_Phdr *phdr; 475 int phnum; 476 caddr_t entry; 477 478 dbg("processing main program's program header"); 479 assert(aux_info[AT_PHDR] != NULL); 480 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 481 assert(aux_info[AT_PHNUM] != NULL); 482 phnum = aux_info[AT_PHNUM]->a_un.a_val; 483 assert(aux_info[AT_PHENT] != NULL); 484 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 485 assert(aux_info[AT_ENTRY] != NULL); 486 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 487 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 488 rtld_die(); 489 } 490 491 if (aux_info[AT_EXECPATH] != 0) { 492 char *kexecpath; 493 char buf[MAXPATHLEN]; 494 495 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 496 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 497 if (kexecpath[0] == '/') 498 obj_main->path = kexecpath; 499 else if (getcwd(buf, sizeof(buf)) == NULL || 500 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 501 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 502 obj_main->path = xstrdup(argv0); 503 else 504 obj_main->path = xstrdup(buf); 505 } else { 506 dbg("No AT_EXECPATH"); 507 obj_main->path = xstrdup(argv0); 508 } 509 dbg("obj_main path %s", obj_main->path); 510 obj_main->mainprog = true; 511 512 if (aux_info[AT_STACKPROT] != NULL && 513 aux_info[AT_STACKPROT]->a_un.a_val != 0) 514 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 515 516#ifndef COMPAT_32BIT 517 /* 518 * Get the actual dynamic linker pathname from the executable if 519 * possible. (It should always be possible.) That ensures that 520 * gdb will find the right dynamic linker even if a non-standard 521 * one is being used. 522 */ 523 if (obj_main->interp != NULL && 524 strcmp(obj_main->interp, obj_rtld.path) != 0) { 525 free(obj_rtld.path); 526 obj_rtld.path = xstrdup(obj_main->interp); 527 __progname = obj_rtld.path; 528 } 529#endif 530 531 digest_dynamic(obj_main, 0); 532 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 533 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 534 obj_main->dynsymcount); 535 536 linkmap_add(obj_main); 537 linkmap_add(&obj_rtld); 538 539 /* Link the main program into the list of objects. */ 540 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 541 obj_count++; 542 obj_loads++; 543 544 /* Initialize a fake symbol for resolving undefined weak references. */ 545 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 546 sym_zero.st_shndx = SHN_UNDEF; 547 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 548 549 if (!libmap_disable) 550 libmap_disable = (bool)lm_init(libmap_override); 551 552 dbg("loading LD_PRELOAD libraries"); 553 if (load_preload_objects() == -1) 554 rtld_die(); 555 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 556 557 dbg("loading needed objects"); 558 if (load_needed_objects(obj_main, 0) == -1) 559 rtld_die(); 560 561 /* Make a list of all objects loaded at startup. */ 562 last_interposer = obj_main; 563 TAILQ_FOREACH(obj, &obj_list, next) { 564 if (obj->marker) 565 continue; 566 if (obj->z_interpose && obj != obj_main) { 567 objlist_put_after(&list_main, last_interposer, obj); 568 last_interposer = obj; 569 } else { 570 objlist_push_tail(&list_main, obj); 571 } 572 obj->refcount++; 573 } 574 575 dbg("checking for required versions"); 576 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 577 rtld_die(); 578 579 if (ld_tracing) { /* We're done */ 580 trace_loaded_objects(obj_main); 581 exit(0); 582 } 583 584 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 585 dump_relocations(obj_main); 586 exit (0); 587 } 588 589 /* 590 * Processing tls relocations requires having the tls offsets 591 * initialized. Prepare offsets before starting initial 592 * relocation processing. 593 */ 594 dbg("initializing initial thread local storage offsets"); 595 STAILQ_FOREACH(entry, &list_main, link) { 596 /* 597 * Allocate all the initial objects out of the static TLS 598 * block even if they didn't ask for it. 599 */ 600 allocate_tls_offset(entry->obj); 601 } 602 603 if (relocate_objects(obj_main, 604 ld_bind_now != NULL && *ld_bind_now != '\0', 605 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 606 rtld_die(); 607 608 dbg("doing copy relocations"); 609 if (do_copy_relocations(obj_main) == -1) 610 rtld_die(); 611 612 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 613 dump_relocations(obj_main); 614 exit (0); 615 } 616 617 /* 618 * Setup TLS for main thread. This must be done after the 619 * relocations are processed, since tls initialization section 620 * might be the subject for relocations. 621 */ 622 dbg("initializing initial thread local storage"); 623 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 624 625 dbg("initializing key program variables"); 626 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 627 set_program_var("environ", env); 628 set_program_var("__elf_aux_vector", aux); 629 630 /* Make a list of init functions to call. */ 631 objlist_init(&initlist); 632 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 633 preload_tail, &initlist); 634 635 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 636 637 map_stacks_exec(NULL); 638 639 dbg("resolving ifuncs"); 640 if (resolve_objects_ifunc(obj_main, 641 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 642 NULL) == -1) 643 rtld_die(); 644 645 if (!obj_main->crt_no_init) { 646 /* 647 * Make sure we don't call the main program's init and fini 648 * functions for binaries linked with old crt1 which calls 649 * _init itself. 650 */ 651 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 652 obj_main->preinit_array = obj_main->init_array = 653 obj_main->fini_array = (Elf_Addr)NULL; 654 } 655 656 wlock_acquire(rtld_bind_lock, &lockstate); 657 if (obj_main->crt_no_init) 658 preinit_main(); 659 objlist_call_init(&initlist, &lockstate); 660 _r_debug_postinit(&obj_main->linkmap); 661 objlist_clear(&initlist); 662 dbg("loading filtees"); 663 TAILQ_FOREACH(obj, &obj_list, next) { 664 if (obj->marker) 665 continue; 666 if (ld_loadfltr || obj->z_loadfltr) 667 load_filtees(obj, 0, &lockstate); 668 } 669 lock_release(rtld_bind_lock, &lockstate); 670 671 dbg("transferring control to program entry point = %p", obj_main->entry); 672 673 /* Return the exit procedure and the program entry point. */ 674 *exit_proc = rtld_exit; 675 *objp = obj_main; 676 return (func_ptr_type) obj_main->entry; 677} 678 679void * 680rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 681{ 682 void *ptr; 683 Elf_Addr target; 684 685 ptr = (void *)make_function_pointer(def, obj); 686 target = ((Elf_Addr (*)(void))ptr)(); 687 return ((void *)target); 688} 689 690Elf_Addr 691_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 692{ 693 const Elf_Rel *rel; 694 const Elf_Sym *def; 695 const Obj_Entry *defobj; 696 Elf_Addr *where; 697 Elf_Addr target; 698 RtldLockState lockstate; 699 700 rlock_acquire(rtld_bind_lock, &lockstate); 701 if (sigsetjmp(lockstate.env, 0) != 0) 702 lock_upgrade(rtld_bind_lock, &lockstate); 703 if (obj->pltrel) 704 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 705 else 706 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 707 708 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 709 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 710 &lockstate); 711 if (def == NULL) 712 rtld_die(); 713 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 714 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 715 else 716 target = (Elf_Addr)(defobj->relocbase + def->st_value); 717 718 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 719 defobj->strtab + def->st_name, basename(obj->path), 720 (void *)target, basename(defobj->path)); 721 722 /* 723 * Write the new contents for the jmpslot. Note that depending on 724 * architecture, the value which we need to return back to the 725 * lazy binding trampoline may or may not be the target 726 * address. The value returned from reloc_jmpslot() is the value 727 * that the trampoline needs. 728 */ 729 target = reloc_jmpslot(where, target, defobj, obj, rel); 730 lock_release(rtld_bind_lock, &lockstate); 731 return target; 732} 733 734/* 735 * Error reporting function. Use it like printf. If formats the message 736 * into a buffer, and sets things up so that the next call to dlerror() 737 * will return the message. 738 */ 739void 740_rtld_error(const char *fmt, ...) 741{ 742 static char buf[512]; 743 va_list ap; 744 745 va_start(ap, fmt); 746 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 747 error_message = buf; 748 va_end(ap); 749} 750 751/* 752 * Return a dynamically-allocated copy of the current error message, if any. 753 */ 754static char * 755errmsg_save(void) 756{ 757 return error_message == NULL ? NULL : xstrdup(error_message); 758} 759 760/* 761 * Restore the current error message from a copy which was previously saved 762 * by errmsg_save(). The copy is freed. 763 */ 764static void 765errmsg_restore(char *saved_msg) 766{ 767 if (saved_msg == NULL) 768 error_message = NULL; 769 else { 770 _rtld_error("%s", saved_msg); 771 free(saved_msg); 772 } 773} 774 775static const char * 776basename(const char *name) 777{ 778 const char *p = strrchr(name, '/'); 779 return p != NULL ? p + 1 : name; 780} 781 782static struct utsname uts; 783 784static char * 785origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 786 const char *subst, bool may_free) 787{ 788 char *p, *p1, *res, *resp; 789 int subst_len, kw_len, subst_count, old_len, new_len; 790 791 kw_len = strlen(kw); 792 793 /* 794 * First, count the number of the keyword occurences, to 795 * preallocate the final string. 796 */ 797 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 798 p1 = strstr(p, kw); 799 if (p1 == NULL) 800 break; 801 } 802 803 /* 804 * If the keyword is not found, just return. 805 * 806 * Return non-substituted string if resolution failed. We 807 * cannot do anything more reasonable, the failure mode of the 808 * caller is unresolved library anyway. 809 */ 810 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 811 return (may_free ? real : xstrdup(real)); 812 if (obj != NULL) 813 subst = obj->origin_path; 814 815 /* 816 * There is indeed something to substitute. Calculate the 817 * length of the resulting string, and allocate it. 818 */ 819 subst_len = strlen(subst); 820 old_len = strlen(real); 821 new_len = old_len + (subst_len - kw_len) * subst_count; 822 res = xmalloc(new_len + 1); 823 824 /* 825 * Now, execute the substitution loop. 826 */ 827 for (p = real, resp = res, *resp = '\0';;) { 828 p1 = strstr(p, kw); 829 if (p1 != NULL) { 830 /* Copy the prefix before keyword. */ 831 memcpy(resp, p, p1 - p); 832 resp += p1 - p; 833 /* Keyword replacement. */ 834 memcpy(resp, subst, subst_len); 835 resp += subst_len; 836 *resp = '\0'; 837 p = p1 + kw_len; 838 } else 839 break; 840 } 841 842 /* Copy to the end of string and finish. */ 843 strcat(resp, p); 844 if (may_free) 845 free(real); 846 return (res); 847} 848 849static char * 850origin_subst(Obj_Entry *obj, char *real) 851{ 852 char *res1, *res2, *res3, *res4; 853 854 if (obj == NULL || !trust) 855 return (xstrdup(real)); 856 if (uts.sysname[0] == '\0') { 857 if (uname(&uts) != 0) { 858 _rtld_error("utsname failed: %d", errno); 859 return (NULL); 860 } 861 } 862 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 863 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 864 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 865 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 866 return (res4); 867} 868 869void 870rtld_die(void) 871{ 872 const char *msg = dlerror(); 873 874 if (msg == NULL) 875 msg = "Fatal error"; 876 rtld_fdputstr(STDERR_FILENO, msg); 877 rtld_fdputchar(STDERR_FILENO, '\n'); 878 _exit(1); 879} 880 881/* 882 * Process a shared object's DYNAMIC section, and save the important 883 * information in its Obj_Entry structure. 884 */ 885static void 886digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 887 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 888{ 889 const Elf_Dyn *dynp; 890 Needed_Entry **needed_tail = &obj->needed; 891 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 892 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 893 const Elf_Hashelt *hashtab; 894 const Elf32_Word *hashval; 895 Elf32_Word bkt, nmaskwords; 896 int bloom_size32; 897 int plttype = DT_REL; 898 899 *dyn_rpath = NULL; 900 *dyn_soname = NULL; 901 *dyn_runpath = NULL; 902 903 obj->bind_now = false; 904 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 905 switch (dynp->d_tag) { 906 907 case DT_REL: 908 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 909 break; 910 911 case DT_RELSZ: 912 obj->relsize = dynp->d_un.d_val; 913 break; 914 915 case DT_RELENT: 916 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 917 break; 918 919 case DT_JMPREL: 920 obj->pltrel = (const Elf_Rel *) 921 (obj->relocbase + dynp->d_un.d_ptr); 922 break; 923 924 case DT_PLTRELSZ: 925 obj->pltrelsize = dynp->d_un.d_val; 926 break; 927 928 case DT_RELA: 929 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 930 break; 931 932 case DT_RELASZ: 933 obj->relasize = dynp->d_un.d_val; 934 break; 935 936 case DT_RELAENT: 937 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 938 break; 939 940 case DT_PLTREL: 941 plttype = dynp->d_un.d_val; 942 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 943 break; 944 945 case DT_SYMTAB: 946 obj->symtab = (const Elf_Sym *) 947 (obj->relocbase + dynp->d_un.d_ptr); 948 break; 949 950 case DT_SYMENT: 951 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 952 break; 953 954 case DT_STRTAB: 955 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 956 break; 957 958 case DT_STRSZ: 959 obj->strsize = dynp->d_un.d_val; 960 break; 961 962 case DT_VERNEED: 963 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 964 dynp->d_un.d_val); 965 break; 966 967 case DT_VERNEEDNUM: 968 obj->verneednum = dynp->d_un.d_val; 969 break; 970 971 case DT_VERDEF: 972 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 973 dynp->d_un.d_val); 974 break; 975 976 case DT_VERDEFNUM: 977 obj->verdefnum = dynp->d_un.d_val; 978 break; 979 980 case DT_VERSYM: 981 obj->versyms = (const Elf_Versym *)(obj->relocbase + 982 dynp->d_un.d_val); 983 break; 984 985 case DT_HASH: 986 { 987 hashtab = (const Elf_Hashelt *)(obj->relocbase + 988 dynp->d_un.d_ptr); 989 obj->nbuckets = hashtab[0]; 990 obj->nchains = hashtab[1]; 991 obj->buckets = hashtab + 2; 992 obj->chains = obj->buckets + obj->nbuckets; 993 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 994 obj->buckets != NULL; 995 } 996 break; 997 998 case DT_GNU_HASH: 999 { 1000 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1001 dynp->d_un.d_ptr); 1002 obj->nbuckets_gnu = hashtab[0]; 1003 obj->symndx_gnu = hashtab[1]; 1004 nmaskwords = hashtab[2]; 1005 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1006 obj->maskwords_bm_gnu = nmaskwords - 1; 1007 obj->shift2_gnu = hashtab[3]; 1008 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1009 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1010 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1011 obj->symndx_gnu; 1012 /* Number of bitmask words is required to be power of 2 */ 1013 obj->valid_hash_gnu = powerof2(nmaskwords) && 1014 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1015 } 1016 break; 1017 1018 case DT_NEEDED: 1019 if (!obj->rtld) { 1020 Needed_Entry *nep = NEW(Needed_Entry); 1021 nep->name = dynp->d_un.d_val; 1022 nep->obj = NULL; 1023 nep->next = NULL; 1024 1025 *needed_tail = nep; 1026 needed_tail = &nep->next; 1027 } 1028 break; 1029 1030 case DT_FILTER: 1031 if (!obj->rtld) { 1032 Needed_Entry *nep = NEW(Needed_Entry); 1033 nep->name = dynp->d_un.d_val; 1034 nep->obj = NULL; 1035 nep->next = NULL; 1036 1037 *needed_filtees_tail = nep; 1038 needed_filtees_tail = &nep->next; 1039 } 1040 break; 1041 1042 case DT_AUXILIARY: 1043 if (!obj->rtld) { 1044 Needed_Entry *nep = NEW(Needed_Entry); 1045 nep->name = dynp->d_un.d_val; 1046 nep->obj = NULL; 1047 nep->next = NULL; 1048 1049 *needed_aux_filtees_tail = nep; 1050 needed_aux_filtees_tail = &nep->next; 1051 } 1052 break; 1053 1054 case DT_PLTGOT: 1055 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1056 break; 1057 1058 case DT_TEXTREL: 1059 obj->textrel = true; 1060 break; 1061 1062 case DT_SYMBOLIC: 1063 obj->symbolic = true; 1064 break; 1065 1066 case DT_RPATH: 1067 /* 1068 * We have to wait until later to process this, because we 1069 * might not have gotten the address of the string table yet. 1070 */ 1071 *dyn_rpath = dynp; 1072 break; 1073 1074 case DT_SONAME: 1075 *dyn_soname = dynp; 1076 break; 1077 1078 case DT_RUNPATH: 1079 *dyn_runpath = dynp; 1080 break; 1081 1082 case DT_INIT: 1083 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1084 break; 1085 1086 case DT_PREINIT_ARRAY: 1087 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1088 break; 1089 1090 case DT_PREINIT_ARRAYSZ: 1091 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1092 break; 1093 1094 case DT_INIT_ARRAY: 1095 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1096 break; 1097 1098 case DT_INIT_ARRAYSZ: 1099 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1100 break; 1101 1102 case DT_FINI: 1103 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1104 break; 1105 1106 case DT_FINI_ARRAY: 1107 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1108 break; 1109 1110 case DT_FINI_ARRAYSZ: 1111 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1112 break; 1113 1114 /* 1115 * Don't process DT_DEBUG on MIPS as the dynamic section 1116 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1117 */ 1118 1119#ifndef __mips__ 1120 case DT_DEBUG: 1121 if (!early) 1122 dbg("Filling in DT_DEBUG entry"); 1123 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1124 break; 1125#endif 1126 1127 case DT_FLAGS: 1128 if (dynp->d_un.d_val & DF_ORIGIN) 1129 obj->z_origin = true; 1130 if (dynp->d_un.d_val & DF_SYMBOLIC) 1131 obj->symbolic = true; 1132 if (dynp->d_un.d_val & DF_TEXTREL) 1133 obj->textrel = true; 1134 if (dynp->d_un.d_val & DF_BIND_NOW) 1135 obj->bind_now = true; 1136 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1137 ;*/ 1138 break; 1139#ifdef __mips__ 1140 case DT_MIPS_LOCAL_GOTNO: 1141 obj->local_gotno = dynp->d_un.d_val; 1142 break; 1143 1144 case DT_MIPS_SYMTABNO: 1145 obj->symtabno = dynp->d_un.d_val; 1146 break; 1147 1148 case DT_MIPS_GOTSYM: 1149 obj->gotsym = dynp->d_un.d_val; 1150 break; 1151 1152 case DT_MIPS_RLD_MAP: 1153 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1154 break; 1155#endif 1156 1157 case DT_FLAGS_1: 1158 if (dynp->d_un.d_val & DF_1_NOOPEN) 1159 obj->z_noopen = true; 1160 if (dynp->d_un.d_val & DF_1_ORIGIN) 1161 obj->z_origin = true; 1162 if (dynp->d_un.d_val & DF_1_GLOBAL) 1163 obj->z_global = true; 1164 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1165 obj->bind_now = true; 1166 if (dynp->d_un.d_val & DF_1_NODELETE) 1167 obj->z_nodelete = true; 1168 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1169 obj->z_loadfltr = true; 1170 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1171 obj->z_interpose = true; 1172 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1173 obj->z_nodeflib = true; 1174 break; 1175 1176 default: 1177 if (!early) { 1178 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1179 (long)dynp->d_tag); 1180 } 1181 break; 1182 } 1183 } 1184 1185 obj->traced = false; 1186 1187 if (plttype == DT_RELA) { 1188 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1189 obj->pltrel = NULL; 1190 obj->pltrelasize = obj->pltrelsize; 1191 obj->pltrelsize = 0; 1192 } 1193 1194 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1195 if (obj->valid_hash_sysv) 1196 obj->dynsymcount = obj->nchains; 1197 else if (obj->valid_hash_gnu) { 1198 obj->dynsymcount = 0; 1199 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1200 if (obj->buckets_gnu[bkt] == 0) 1201 continue; 1202 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1203 do 1204 obj->dynsymcount++; 1205 while ((*hashval++ & 1u) == 0); 1206 } 1207 obj->dynsymcount += obj->symndx_gnu; 1208 } 1209} 1210 1211static bool 1212obj_resolve_origin(Obj_Entry *obj) 1213{ 1214 1215 if (obj->origin_path != NULL) 1216 return (true); 1217 obj->origin_path = xmalloc(PATH_MAX); 1218 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1219} 1220 1221static void 1222digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1223 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1224{ 1225 1226 if (obj->z_origin && !obj_resolve_origin(obj)) 1227 rtld_die(); 1228 1229 if (dyn_runpath != NULL) { 1230 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1231 obj->runpath = origin_subst(obj, obj->runpath); 1232 } else if (dyn_rpath != NULL) { 1233 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1234 obj->rpath = origin_subst(obj, obj->rpath); 1235 } 1236 if (dyn_soname != NULL) 1237 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1238} 1239 1240static void 1241digest_dynamic(Obj_Entry *obj, int early) 1242{ 1243 const Elf_Dyn *dyn_rpath; 1244 const Elf_Dyn *dyn_soname; 1245 const Elf_Dyn *dyn_runpath; 1246 1247 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1248 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1249} 1250 1251/* 1252 * Process a shared object's program header. This is used only for the 1253 * main program, when the kernel has already loaded the main program 1254 * into memory before calling the dynamic linker. It creates and 1255 * returns an Obj_Entry structure. 1256 */ 1257static Obj_Entry * 1258digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1259{ 1260 Obj_Entry *obj; 1261 const Elf_Phdr *phlimit = phdr + phnum; 1262 const Elf_Phdr *ph; 1263 Elf_Addr note_start, note_end; 1264 int nsegs = 0; 1265 1266 obj = obj_new(); 1267 for (ph = phdr; ph < phlimit; ph++) { 1268 if (ph->p_type != PT_PHDR) 1269 continue; 1270 1271 obj->phdr = phdr; 1272 obj->phsize = ph->p_memsz; 1273 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1274 break; 1275 } 1276 1277 obj->stack_flags = PF_X | PF_R | PF_W; 1278 1279 for (ph = phdr; ph < phlimit; ph++) { 1280 switch (ph->p_type) { 1281 1282 case PT_INTERP: 1283 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1284 break; 1285 1286 case PT_LOAD: 1287 if (nsegs == 0) { /* First load segment */ 1288 obj->vaddrbase = trunc_page(ph->p_vaddr); 1289 obj->mapbase = obj->vaddrbase + obj->relocbase; 1290 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1291 obj->vaddrbase; 1292 } else { /* Last load segment */ 1293 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1294 obj->vaddrbase; 1295 } 1296 nsegs++; 1297 break; 1298 1299 case PT_DYNAMIC: 1300 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1301 break; 1302 1303 case PT_TLS: 1304 obj->tlsindex = 1; 1305 obj->tlssize = ph->p_memsz; 1306 obj->tlsalign = ph->p_align; 1307 obj->tlsinitsize = ph->p_filesz; 1308 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1309 break; 1310 1311 case PT_GNU_STACK: 1312 obj->stack_flags = ph->p_flags; 1313 break; 1314 1315 case PT_GNU_RELRO: 1316 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1317 obj->relro_size = round_page(ph->p_memsz); 1318 break; 1319 1320 case PT_NOTE: 1321 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1322 note_end = note_start + ph->p_filesz; 1323 digest_notes(obj, note_start, note_end); 1324 break; 1325 } 1326 } 1327 if (nsegs < 1) { 1328 _rtld_error("%s: too few PT_LOAD segments", path); 1329 return NULL; 1330 } 1331 1332 obj->entry = entry; 1333 return obj; 1334} 1335 1336void 1337digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1338{ 1339 const Elf_Note *note; 1340 const char *note_name; 1341 uintptr_t p; 1342 1343 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1344 note = (const Elf_Note *)((const char *)(note + 1) + 1345 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1346 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1347 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1348 note->n_descsz != sizeof(int32_t)) 1349 continue; 1350 if (note->n_type != ABI_NOTETYPE && 1351 note->n_type != CRT_NOINIT_NOTETYPE) 1352 continue; 1353 note_name = (const char *)(note + 1); 1354 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1355 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1356 continue; 1357 switch (note->n_type) { 1358 case ABI_NOTETYPE: 1359 /* FreeBSD osrel note */ 1360 p = (uintptr_t)(note + 1); 1361 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1362 obj->osrel = *(const int32_t *)(p); 1363 dbg("note osrel %d", obj->osrel); 1364 break; 1365 case CRT_NOINIT_NOTETYPE: 1366 /* FreeBSD 'crt does not call init' note */ 1367 obj->crt_no_init = true; 1368 dbg("note crt_no_init"); 1369 break; 1370 } 1371 } 1372} 1373 1374static Obj_Entry * 1375dlcheck(void *handle) 1376{ 1377 Obj_Entry *obj; 1378 1379 TAILQ_FOREACH(obj, &obj_list, next) { 1380 if (obj == (Obj_Entry *) handle) 1381 break; 1382 } 1383 1384 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1385 _rtld_error("Invalid shared object handle %p", handle); 1386 return NULL; 1387 } 1388 return obj; 1389} 1390 1391/* 1392 * If the given object is already in the donelist, return true. Otherwise 1393 * add the object to the list and return false. 1394 */ 1395static bool 1396donelist_check(DoneList *dlp, const Obj_Entry *obj) 1397{ 1398 unsigned int i; 1399 1400 for (i = 0; i < dlp->num_used; i++) 1401 if (dlp->objs[i] == obj) 1402 return true; 1403 /* 1404 * Our donelist allocation should always be sufficient. But if 1405 * our threads locking isn't working properly, more shared objects 1406 * could have been loaded since we allocated the list. That should 1407 * never happen, but we'll handle it properly just in case it does. 1408 */ 1409 if (dlp->num_used < dlp->num_alloc) 1410 dlp->objs[dlp->num_used++] = obj; 1411 return false; 1412} 1413 1414/* 1415 * Hash function for symbol table lookup. Don't even think about changing 1416 * this. It is specified by the System V ABI. 1417 */ 1418unsigned long 1419elf_hash(const char *name) 1420{ 1421 const unsigned char *p = (const unsigned char *) name; 1422 unsigned long h = 0; 1423 unsigned long g; 1424 1425 while (*p != '\0') { 1426 h = (h << 4) + *p++; 1427 if ((g = h & 0xf0000000) != 0) 1428 h ^= g >> 24; 1429 h &= ~g; 1430 } 1431 return h; 1432} 1433 1434/* 1435 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1436 * unsigned in case it's implemented with a wider type. 1437 */ 1438static uint32_t 1439gnu_hash(const char *s) 1440{ 1441 uint32_t h; 1442 unsigned char c; 1443 1444 h = 5381; 1445 for (c = *s; c != '\0'; c = *++s) 1446 h = h * 33 + c; 1447 return (h & 0xffffffff); 1448} 1449 1450/* 1451 * Find the library with the given name, and return its full pathname. 1452 * The returned string is dynamically allocated. Generates an error 1453 * message and returns NULL if the library cannot be found. 1454 * 1455 * If the second argument is non-NULL, then it refers to an already- 1456 * loaded shared object, whose library search path will be searched. 1457 * 1458 * The search order is: 1459 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1460 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1461 * LD_LIBRARY_PATH 1462 * DT_RUNPATH in the referencing file 1463 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1464 * from list) 1465 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1466 * 1467 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1468 */ 1469static char * 1470find_library(const char *xname, const Obj_Entry *refobj) 1471{ 1472 char *pathname; 1473 char *name; 1474 bool nodeflib, objgiven; 1475 1476 objgiven = refobj != NULL; 1477 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1478 if (xname[0] != '/' && !trust) { 1479 _rtld_error("Absolute pathname required for shared object \"%s\"", 1480 xname); 1481 return NULL; 1482 } 1483 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1484 __DECONST(char *, xname))); 1485 } 1486 1487 if (libmap_disable || !objgiven || 1488 (name = lm_find(refobj->path, xname)) == NULL) 1489 name = (char *)xname; 1490 1491 dbg(" Searching for \"%s\"", name); 1492 1493 /* 1494 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1495 * back to pre-conforming behaviour if user requested so with 1496 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1497 * nodeflib. 1498 */ 1499 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1500 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1501 (refobj != NULL && 1502 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1503 (pathname = search_library_path(name, gethints(false))) != NULL || 1504 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1505 return (pathname); 1506 } else { 1507 nodeflib = objgiven ? refobj->z_nodeflib : false; 1508 if ((objgiven && 1509 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1510 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1511 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1512 (pathname = search_library_path(name, ld_library_path)) != NULL || 1513 (objgiven && 1514 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1515 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1516 (objgiven && !nodeflib && 1517 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1518 return (pathname); 1519 } 1520 1521 if (objgiven && refobj->path != NULL) { 1522 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1523 name, basename(refobj->path)); 1524 } else { 1525 _rtld_error("Shared object \"%s\" not found", name); 1526 } 1527 return NULL; 1528} 1529 1530/* 1531 * Given a symbol number in a referencing object, find the corresponding 1532 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1533 * no definition was found. Returns a pointer to the Obj_Entry of the 1534 * defining object via the reference parameter DEFOBJ_OUT. 1535 */ 1536const Elf_Sym * 1537find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1538 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1539 RtldLockState *lockstate) 1540{ 1541 const Elf_Sym *ref; 1542 const Elf_Sym *def; 1543 const Obj_Entry *defobj; 1544 SymLook req; 1545 const char *name; 1546 int res; 1547 1548 /* 1549 * If we have already found this symbol, get the information from 1550 * the cache. 1551 */ 1552 if (symnum >= refobj->dynsymcount) 1553 return NULL; /* Bad object */ 1554 if (cache != NULL && cache[symnum].sym != NULL) { 1555 *defobj_out = cache[symnum].obj; 1556 return cache[symnum].sym; 1557 } 1558 1559 ref = refobj->symtab + symnum; 1560 name = refobj->strtab + ref->st_name; 1561 def = NULL; 1562 defobj = NULL; 1563 1564 /* 1565 * We don't have to do a full scale lookup if the symbol is local. 1566 * We know it will bind to the instance in this load module; to 1567 * which we already have a pointer (ie ref). By not doing a lookup, 1568 * we not only improve performance, but it also avoids unresolvable 1569 * symbols when local symbols are not in the hash table. This has 1570 * been seen with the ia64 toolchain. 1571 */ 1572 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1573 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1574 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1575 symnum); 1576 } 1577 symlook_init(&req, name); 1578 req.flags = flags; 1579 req.ventry = fetch_ventry(refobj, symnum); 1580 req.lockstate = lockstate; 1581 res = symlook_default(&req, refobj); 1582 if (res == 0) { 1583 def = req.sym_out; 1584 defobj = req.defobj_out; 1585 } 1586 } else { 1587 def = ref; 1588 defobj = refobj; 1589 } 1590 1591 /* 1592 * If we found no definition and the reference is weak, treat the 1593 * symbol as having the value zero. 1594 */ 1595 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1596 def = &sym_zero; 1597 defobj = obj_main; 1598 } 1599 1600 if (def != NULL) { 1601 *defobj_out = defobj; 1602 /* Record the information in the cache to avoid subsequent lookups. */ 1603 if (cache != NULL) { 1604 cache[symnum].sym = def; 1605 cache[symnum].obj = defobj; 1606 } 1607 } else { 1608 if (refobj != &obj_rtld) 1609 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1610 } 1611 return def; 1612} 1613 1614/* 1615 * Return the search path from the ldconfig hints file, reading it if 1616 * necessary. If nostdlib is true, then the default search paths are 1617 * not added to result. 1618 * 1619 * Returns NULL if there are problems with the hints file, 1620 * or if the search path there is empty. 1621 */ 1622static const char * 1623gethints(bool nostdlib) 1624{ 1625 static char *hints, *filtered_path; 1626 struct elfhints_hdr hdr; 1627 struct fill_search_info_args sargs, hargs; 1628 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1629 struct dl_serpath *SLPpath, *hintpath; 1630 char *p; 1631 unsigned int SLPndx, hintndx, fndx, fcount; 1632 int fd; 1633 size_t flen; 1634 bool skip; 1635 1636 /* First call, read the hints file */ 1637 if (hints == NULL) { 1638 /* Keep from trying again in case the hints file is bad. */ 1639 hints = ""; 1640 1641 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1642 return (NULL); 1643 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1644 hdr.magic != ELFHINTS_MAGIC || 1645 hdr.version != 1) { 1646 close(fd); 1647 return (NULL); 1648 } 1649 p = xmalloc(hdr.dirlistlen + 1); 1650 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1651 read(fd, p, hdr.dirlistlen + 1) != 1652 (ssize_t)hdr.dirlistlen + 1) { 1653 free(p); 1654 close(fd); 1655 return (NULL); 1656 } 1657 hints = p; 1658 close(fd); 1659 } 1660 1661 /* 1662 * If caller agreed to receive list which includes the default 1663 * paths, we are done. Otherwise, if we still did not 1664 * calculated filtered result, do it now. 1665 */ 1666 if (!nostdlib) 1667 return (hints[0] != '\0' ? hints : NULL); 1668 if (filtered_path != NULL) 1669 goto filt_ret; 1670 1671 /* 1672 * Obtain the list of all configured search paths, and the 1673 * list of the default paths. 1674 * 1675 * First estimate the size of the results. 1676 */ 1677 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1678 smeta.dls_cnt = 0; 1679 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1680 hmeta.dls_cnt = 0; 1681 1682 sargs.request = RTLD_DI_SERINFOSIZE; 1683 sargs.serinfo = &smeta; 1684 hargs.request = RTLD_DI_SERINFOSIZE; 1685 hargs.serinfo = &hmeta; 1686 1687 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1688 path_enumerate(p, fill_search_info, &hargs); 1689 1690 SLPinfo = xmalloc(smeta.dls_size); 1691 hintinfo = xmalloc(hmeta.dls_size); 1692 1693 /* 1694 * Next fetch both sets of paths. 1695 */ 1696 sargs.request = RTLD_DI_SERINFO; 1697 sargs.serinfo = SLPinfo; 1698 sargs.serpath = &SLPinfo->dls_serpath[0]; 1699 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1700 1701 hargs.request = RTLD_DI_SERINFO; 1702 hargs.serinfo = hintinfo; 1703 hargs.serpath = &hintinfo->dls_serpath[0]; 1704 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1705 1706 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1707 path_enumerate(p, fill_search_info, &hargs); 1708 1709 /* 1710 * Now calculate the difference between two sets, by excluding 1711 * standard paths from the full set. 1712 */ 1713 fndx = 0; 1714 fcount = 0; 1715 filtered_path = xmalloc(hdr.dirlistlen + 1); 1716 hintpath = &hintinfo->dls_serpath[0]; 1717 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1718 skip = false; 1719 SLPpath = &SLPinfo->dls_serpath[0]; 1720 /* 1721 * Check each standard path against current. 1722 */ 1723 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1724 /* matched, skip the path */ 1725 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1726 skip = true; 1727 break; 1728 } 1729 } 1730 if (skip) 1731 continue; 1732 /* 1733 * Not matched against any standard path, add the path 1734 * to result. Separate consequtive paths with ':'. 1735 */ 1736 if (fcount > 0) { 1737 filtered_path[fndx] = ':'; 1738 fndx++; 1739 } 1740 fcount++; 1741 flen = strlen(hintpath->dls_name); 1742 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1743 fndx += flen; 1744 } 1745 filtered_path[fndx] = '\0'; 1746 1747 free(SLPinfo); 1748 free(hintinfo); 1749 1750filt_ret: 1751 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1752} 1753 1754static void 1755init_dag(Obj_Entry *root) 1756{ 1757 const Needed_Entry *needed; 1758 const Objlist_Entry *elm; 1759 DoneList donelist; 1760 1761 if (root->dag_inited) 1762 return; 1763 donelist_init(&donelist); 1764 1765 /* Root object belongs to own DAG. */ 1766 objlist_push_tail(&root->dldags, root); 1767 objlist_push_tail(&root->dagmembers, root); 1768 donelist_check(&donelist, root); 1769 1770 /* 1771 * Add dependencies of root object to DAG in breadth order 1772 * by exploiting the fact that each new object get added 1773 * to the tail of the dagmembers list. 1774 */ 1775 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1776 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1777 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1778 continue; 1779 objlist_push_tail(&needed->obj->dldags, root); 1780 objlist_push_tail(&root->dagmembers, needed->obj); 1781 } 1782 } 1783 root->dag_inited = true; 1784} 1785 1786Obj_Entry * 1787globallist_curr(const Obj_Entry *obj) 1788{ 1789 1790 for (;;) { 1791 if (obj == NULL) 1792 return (NULL); 1793 if (!obj->marker) 1794 return (__DECONST(Obj_Entry *, obj)); 1795 obj = TAILQ_PREV(obj, obj_entry_q, next); 1796 } 1797} 1798 1799Obj_Entry * 1800globallist_next(const Obj_Entry *obj) 1801{ 1802 1803 for (;;) { 1804 obj = TAILQ_NEXT(obj, next); 1805 if (obj == NULL) 1806 return (NULL); 1807 if (!obj->marker) 1808 return (__DECONST(Obj_Entry *, obj)); 1809 } 1810} 1811 1812static void 1813process_z(Obj_Entry *root) 1814{ 1815 const Objlist_Entry *elm; 1816 Obj_Entry *obj; 1817 1818 /* 1819 * Walk over object DAG and process every dependent object 1820 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1821 * to grow their own DAG. 1822 * 1823 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1824 * symlook_global() to work. 1825 * 1826 * For DF_1_NODELETE, the DAG should have its reference upped. 1827 */ 1828 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1829 obj = elm->obj; 1830 if (obj == NULL) 1831 continue; 1832 if (obj->z_nodelete && !obj->ref_nodel) { 1833 dbg("obj %s -z nodelete", obj->path); 1834 init_dag(obj); 1835 ref_dag(obj); 1836 obj->ref_nodel = true; 1837 } 1838 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1839 dbg("obj %s -z global", obj->path); 1840 objlist_push_tail(&list_global, obj); 1841 init_dag(obj); 1842 } 1843 } 1844} 1845/* 1846 * Initialize the dynamic linker. The argument is the address at which 1847 * the dynamic linker has been mapped into memory. The primary task of 1848 * this function is to relocate the dynamic linker. 1849 */ 1850static void 1851init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1852{ 1853 Obj_Entry objtmp; /* Temporary rtld object */ 1854 const Elf_Dyn *dyn_rpath; 1855 const Elf_Dyn *dyn_soname; 1856 const Elf_Dyn *dyn_runpath; 1857 1858#ifdef RTLD_INIT_PAGESIZES_EARLY 1859 /* The page size is required by the dynamic memory allocator. */ 1860 init_pagesizes(aux_info); 1861#endif 1862 1863 /* 1864 * Conjure up an Obj_Entry structure for the dynamic linker. 1865 * 1866 * The "path" member can't be initialized yet because string constants 1867 * cannot yet be accessed. Below we will set it correctly. 1868 */ 1869 memset(&objtmp, 0, sizeof(objtmp)); 1870 objtmp.path = NULL; 1871 objtmp.rtld = true; 1872 objtmp.mapbase = mapbase; 1873#ifdef PIC 1874 objtmp.relocbase = mapbase; 1875#endif 1876 if (RTLD_IS_DYNAMIC()) { 1877 objtmp.dynamic = rtld_dynamic(&objtmp); 1878 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1879 assert(objtmp.needed == NULL); 1880#if !defined(__mips__) 1881 /* MIPS has a bogus DT_TEXTREL. */ 1882 assert(!objtmp.textrel); 1883#endif 1884 1885 /* 1886 * Temporarily put the dynamic linker entry into the object list, so 1887 * that symbols can be found. 1888 */ 1889 1890 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1891 } 1892 1893 /* Initialize the object list. */ 1894 TAILQ_INIT(&obj_list); 1895 1896 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1897 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1898 1899#ifndef RTLD_INIT_PAGESIZES_EARLY 1900 /* The page size is required by the dynamic memory allocator. */ 1901 init_pagesizes(aux_info); 1902#endif 1903 1904 if (aux_info[AT_OSRELDATE] != NULL) 1905 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1906 1907 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1908 1909 /* Replace the path with a dynamically allocated copy. */ 1910 obj_rtld.path = xstrdup(PATH_RTLD); 1911 1912 r_debug.r_brk = r_debug_state; 1913 r_debug.r_state = RT_CONSISTENT; 1914} 1915 1916/* 1917 * Retrieve the array of supported page sizes. The kernel provides the page 1918 * sizes in increasing order. 1919 */ 1920static void 1921init_pagesizes(Elf_Auxinfo **aux_info) 1922{ 1923 static size_t psa[MAXPAGESIZES]; 1924 int mib[2]; 1925 size_t len, size; 1926 1927 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1928 NULL) { 1929 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1930 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1931 } else { 1932 len = 2; 1933 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1934 size = sizeof(psa); 1935 else { 1936 /* As a fallback, retrieve the base page size. */ 1937 size = sizeof(psa[0]); 1938 if (aux_info[AT_PAGESZ] != NULL) { 1939 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1940 goto psa_filled; 1941 } else { 1942 mib[0] = CTL_HW; 1943 mib[1] = HW_PAGESIZE; 1944 len = 2; 1945 } 1946 } 1947 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1948 _rtld_error("sysctl for hw.pagesize(s) failed"); 1949 rtld_die(); 1950 } 1951psa_filled: 1952 pagesizes = psa; 1953 } 1954 npagesizes = size / sizeof(pagesizes[0]); 1955 /* Discard any invalid entries at the end of the array. */ 1956 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1957 npagesizes--; 1958} 1959 1960/* 1961 * Add the init functions from a needed object list (and its recursive 1962 * needed objects) to "list". This is not used directly; it is a helper 1963 * function for initlist_add_objects(). The write lock must be held 1964 * when this function is called. 1965 */ 1966static void 1967initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1968{ 1969 /* Recursively process the successor needed objects. */ 1970 if (needed->next != NULL) 1971 initlist_add_neededs(needed->next, list); 1972 1973 /* Process the current needed object. */ 1974 if (needed->obj != NULL) 1975 initlist_add_objects(needed->obj, needed->obj, list); 1976} 1977 1978/* 1979 * Scan all of the DAGs rooted in the range of objects from "obj" to 1980 * "tail" and add their init functions to "list". This recurses over 1981 * the DAGs and ensure the proper init ordering such that each object's 1982 * needed libraries are initialized before the object itself. At the 1983 * same time, this function adds the objects to the global finalization 1984 * list "list_fini" in the opposite order. The write lock must be 1985 * held when this function is called. 1986 */ 1987static void 1988initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 1989{ 1990 Obj_Entry *nobj; 1991 1992 if (obj->init_scanned || obj->init_done) 1993 return; 1994 obj->init_scanned = true; 1995 1996 /* Recursively process the successor objects. */ 1997 nobj = globallist_next(obj); 1998 if (nobj != NULL && obj != tail) 1999 initlist_add_objects(nobj, tail, list); 2000 2001 /* Recursively process the needed objects. */ 2002 if (obj->needed != NULL) 2003 initlist_add_neededs(obj->needed, list); 2004 if (obj->needed_filtees != NULL) 2005 initlist_add_neededs(obj->needed_filtees, list); 2006 if (obj->needed_aux_filtees != NULL) 2007 initlist_add_neededs(obj->needed_aux_filtees, list); 2008 2009 /* Add the object to the init list. */ 2010 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2011 obj->init_array != (Elf_Addr)NULL) 2012 objlist_push_tail(list, obj); 2013 2014 /* Add the object to the global fini list in the reverse order. */ 2015 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2016 && !obj->on_fini_list) { 2017 objlist_push_head(&list_fini, obj); 2018 obj->on_fini_list = true; 2019 } 2020} 2021 2022#ifndef FPTR_TARGET 2023#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2024#endif 2025 2026static void 2027free_needed_filtees(Needed_Entry *n) 2028{ 2029 Needed_Entry *needed, *needed1; 2030 2031 for (needed = n; needed != NULL; needed = needed->next) { 2032 if (needed->obj != NULL) { 2033 dlclose(needed->obj); 2034 needed->obj = NULL; 2035 } 2036 } 2037 for (needed = n; needed != NULL; needed = needed1) { 2038 needed1 = needed->next; 2039 free(needed); 2040 } 2041} 2042 2043static void 2044unload_filtees(Obj_Entry *obj) 2045{ 2046 2047 free_needed_filtees(obj->needed_filtees); 2048 obj->needed_filtees = NULL; 2049 free_needed_filtees(obj->needed_aux_filtees); 2050 obj->needed_aux_filtees = NULL; 2051 obj->filtees_loaded = false; 2052} 2053 2054static void 2055load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2056 RtldLockState *lockstate) 2057{ 2058 2059 for (; needed != NULL; needed = needed->next) { 2060 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2061 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2062 RTLD_LOCAL, lockstate); 2063 } 2064} 2065 2066static void 2067load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2068{ 2069 2070 lock_restart_for_upgrade(lockstate); 2071 if (!obj->filtees_loaded) { 2072 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2073 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2074 obj->filtees_loaded = true; 2075 } 2076} 2077 2078static int 2079process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2080{ 2081 Obj_Entry *obj1; 2082 2083 for (; needed != NULL; needed = needed->next) { 2084 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2085 flags & ~RTLD_LO_NOLOAD); 2086 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2087 return (-1); 2088 } 2089 return (0); 2090} 2091 2092/* 2093 * Given a shared object, traverse its list of needed objects, and load 2094 * each of them. Returns 0 on success. Generates an error message and 2095 * returns -1 on failure. 2096 */ 2097static int 2098load_needed_objects(Obj_Entry *first, int flags) 2099{ 2100 Obj_Entry *obj; 2101 2102 obj = first; 2103 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2104 if (obj->marker) 2105 continue; 2106 if (process_needed(obj, obj->needed, flags) == -1) 2107 return (-1); 2108 } 2109 return (0); 2110} 2111 2112static int 2113load_preload_objects(void) 2114{ 2115 char *p = ld_preload; 2116 Obj_Entry *obj; 2117 static const char delim[] = " \t:;"; 2118 2119 if (p == NULL) 2120 return 0; 2121 2122 p += strspn(p, delim); 2123 while (*p != '\0') { 2124 size_t len = strcspn(p, delim); 2125 char savech; 2126 2127 savech = p[len]; 2128 p[len] = '\0'; 2129 obj = load_object(p, -1, NULL, 0); 2130 if (obj == NULL) 2131 return -1; /* XXX - cleanup */ 2132 obj->z_interpose = true; 2133 p[len] = savech; 2134 p += len; 2135 p += strspn(p, delim); 2136 } 2137 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2138 return 0; 2139} 2140 2141static const char * 2142printable_path(const char *path) 2143{ 2144 2145 return (path == NULL ? "<unknown>" : path); 2146} 2147 2148/* 2149 * Load a shared object into memory, if it is not already loaded. The 2150 * object may be specified by name or by user-supplied file descriptor 2151 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2152 * duplicate is. 2153 * 2154 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2155 * on failure. 2156 */ 2157static Obj_Entry * 2158load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2159{ 2160 Obj_Entry *obj; 2161 int fd; 2162 struct stat sb; 2163 char *path; 2164 2165 if (name != NULL) { 2166 TAILQ_FOREACH(obj, &obj_list, next) { 2167 if (obj->marker) 2168 continue; 2169 if (object_match_name(obj, name)) 2170 return (obj); 2171 } 2172 2173 path = find_library(name, refobj); 2174 if (path == NULL) 2175 return (NULL); 2176 } else 2177 path = NULL; 2178 2179 /* 2180 * If we didn't find a match by pathname, or the name is not 2181 * supplied, open the file and check again by device and inode. 2182 * This avoids false mismatches caused by multiple links or ".." 2183 * in pathnames. 2184 * 2185 * To avoid a race, we open the file and use fstat() rather than 2186 * using stat(). 2187 */ 2188 fd = -1; 2189 if (fd_u == -1) { 2190 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2191 _rtld_error("Cannot open \"%s\"", path); 2192 free(path); 2193 return (NULL); 2194 } 2195 } else { 2196 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2197 if (fd == -1) { 2198 _rtld_error("Cannot dup fd"); 2199 free(path); 2200 return (NULL); 2201 } 2202 } 2203 if (fstat(fd, &sb) == -1) { 2204 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2205 close(fd); 2206 free(path); 2207 return NULL; 2208 } 2209 TAILQ_FOREACH(obj, &obj_list, next) { 2210 if (obj->marker) 2211 continue; 2212 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2213 break; 2214 } 2215 if (obj != NULL && name != NULL) { 2216 object_add_name(obj, name); 2217 free(path); 2218 close(fd); 2219 return obj; 2220 } 2221 if (flags & RTLD_LO_NOLOAD) { 2222 free(path); 2223 close(fd); 2224 return (NULL); 2225 } 2226 2227 /* First use of this object, so we must map it in */ 2228 obj = do_load_object(fd, name, path, &sb, flags); 2229 if (obj == NULL) 2230 free(path); 2231 close(fd); 2232 2233 return obj; 2234} 2235 2236static Obj_Entry * 2237do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2238 int flags) 2239{ 2240 Obj_Entry *obj; 2241 struct statfs fs; 2242 2243 /* 2244 * but first, make sure that environment variables haven't been 2245 * used to circumvent the noexec flag on a filesystem. 2246 */ 2247 if (dangerous_ld_env) { 2248 if (fstatfs(fd, &fs) != 0) { 2249 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2250 return NULL; 2251 } 2252 if (fs.f_flags & MNT_NOEXEC) { 2253 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2254 return NULL; 2255 } 2256 } 2257 dbg("loading \"%s\"", printable_path(path)); 2258 obj = map_object(fd, printable_path(path), sbp); 2259 if (obj == NULL) 2260 return NULL; 2261 2262 /* 2263 * If DT_SONAME is present in the object, digest_dynamic2 already 2264 * added it to the object names. 2265 */ 2266 if (name != NULL) 2267 object_add_name(obj, name); 2268 obj->path = path; 2269 digest_dynamic(obj, 0); 2270 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2271 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2272 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2273 RTLD_LO_DLOPEN) { 2274 dbg("refusing to load non-loadable \"%s\"", obj->path); 2275 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2276 munmap(obj->mapbase, obj->mapsize); 2277 obj_free(obj); 2278 return (NULL); 2279 } 2280 2281 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2282 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2283 obj_count++; 2284 obj_loads++; 2285 linkmap_add(obj); /* for GDB & dlinfo() */ 2286 max_stack_flags |= obj->stack_flags; 2287 2288 dbg(" %p .. %p: %s", obj->mapbase, 2289 obj->mapbase + obj->mapsize - 1, obj->path); 2290 if (obj->textrel) 2291 dbg(" WARNING: %s has impure text", obj->path); 2292 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2293 obj->path); 2294 2295 return obj; 2296} 2297 2298static Obj_Entry * 2299obj_from_addr(const void *addr) 2300{ 2301 Obj_Entry *obj; 2302 2303 TAILQ_FOREACH(obj, &obj_list, next) { 2304 if (obj->marker) 2305 continue; 2306 if (addr < (void *) obj->mapbase) 2307 continue; 2308 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2309 return obj; 2310 } 2311 return NULL; 2312} 2313 2314static void 2315preinit_main(void) 2316{ 2317 Elf_Addr *preinit_addr; 2318 int index; 2319 2320 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2321 if (preinit_addr == NULL) 2322 return; 2323 2324 for (index = 0; index < obj_main->preinit_array_num; index++) { 2325 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2326 dbg("calling preinit function for %s at %p", obj_main->path, 2327 (void *)preinit_addr[index]); 2328 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2329 0, 0, obj_main->path); 2330 call_init_pointer(obj_main, preinit_addr[index]); 2331 } 2332 } 2333} 2334 2335/* 2336 * Call the finalization functions for each of the objects in "list" 2337 * belonging to the DAG of "root" and referenced once. If NULL "root" 2338 * is specified, every finalization function will be called regardless 2339 * of the reference count and the list elements won't be freed. All of 2340 * the objects are expected to have non-NULL fini functions. 2341 */ 2342static void 2343objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2344{ 2345 Objlist_Entry *elm; 2346 char *saved_msg; 2347 Elf_Addr *fini_addr; 2348 int index; 2349 2350 assert(root == NULL || root->refcount == 1); 2351 2352 /* 2353 * Preserve the current error message since a fini function might 2354 * call into the dynamic linker and overwrite it. 2355 */ 2356 saved_msg = errmsg_save(); 2357 do { 2358 STAILQ_FOREACH(elm, list, link) { 2359 if (root != NULL && (elm->obj->refcount != 1 || 2360 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2361 continue; 2362 /* Remove object from fini list to prevent recursive invocation. */ 2363 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2364 /* 2365 * XXX: If a dlopen() call references an object while the 2366 * fini function is in progress, we might end up trying to 2367 * unload the referenced object in dlclose() or the object 2368 * won't be unloaded although its fini function has been 2369 * called. 2370 */ 2371 lock_release(rtld_bind_lock, lockstate); 2372 2373 /* 2374 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2375 * When this happens, DT_FINI_ARRAY is processed first. 2376 */ 2377 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2378 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2379 for (index = elm->obj->fini_array_num - 1; index >= 0; 2380 index--) { 2381 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2382 dbg("calling fini function for %s at %p", 2383 elm->obj->path, (void *)fini_addr[index]); 2384 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2385 (void *)fini_addr[index], 0, 0, elm->obj->path); 2386 call_initfini_pointer(elm->obj, fini_addr[index]); 2387 } 2388 } 2389 } 2390 if (elm->obj->fini != (Elf_Addr)NULL) { 2391 dbg("calling fini function for %s at %p", elm->obj->path, 2392 (void *)elm->obj->fini); 2393 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2394 0, 0, elm->obj->path); 2395 call_initfini_pointer(elm->obj, elm->obj->fini); 2396 } 2397 wlock_acquire(rtld_bind_lock, lockstate); 2398 /* No need to free anything if process is going down. */ 2399 if (root != NULL) 2400 free(elm); 2401 /* 2402 * We must restart the list traversal after every fini call 2403 * because a dlclose() call from the fini function or from 2404 * another thread might have modified the reference counts. 2405 */ 2406 break; 2407 } 2408 } while (elm != NULL); 2409 errmsg_restore(saved_msg); 2410} 2411 2412/* 2413 * Call the initialization functions for each of the objects in 2414 * "list". All of the objects are expected to have non-NULL init 2415 * functions. 2416 */ 2417static void 2418objlist_call_init(Objlist *list, RtldLockState *lockstate) 2419{ 2420 Objlist_Entry *elm; 2421 Obj_Entry *obj; 2422 char *saved_msg; 2423 Elf_Addr *init_addr; 2424 int index; 2425 2426 /* 2427 * Clean init_scanned flag so that objects can be rechecked and 2428 * possibly initialized earlier if any of vectors called below 2429 * cause the change by using dlopen. 2430 */ 2431 TAILQ_FOREACH(obj, &obj_list, next) { 2432 if (obj->marker) 2433 continue; 2434 obj->init_scanned = false; 2435 } 2436 2437 /* 2438 * Preserve the current error message since an init function might 2439 * call into the dynamic linker and overwrite it. 2440 */ 2441 saved_msg = errmsg_save(); 2442 STAILQ_FOREACH(elm, list, link) { 2443 if (elm->obj->init_done) /* Initialized early. */ 2444 continue; 2445 /* 2446 * Race: other thread might try to use this object before current 2447 * one completes the initilization. Not much can be done here 2448 * without better locking. 2449 */ 2450 elm->obj->init_done = true; 2451 lock_release(rtld_bind_lock, lockstate); 2452 2453 /* 2454 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2455 * When this happens, DT_INIT is processed first. 2456 */ 2457 if (elm->obj->init != (Elf_Addr)NULL) { 2458 dbg("calling init function for %s at %p", elm->obj->path, 2459 (void *)elm->obj->init); 2460 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2461 0, 0, elm->obj->path); 2462 call_initfini_pointer(elm->obj, elm->obj->init); 2463 } 2464 init_addr = (Elf_Addr *)elm->obj->init_array; 2465 if (init_addr != NULL) { 2466 for (index = 0; index < elm->obj->init_array_num; index++) { 2467 if (init_addr[index] != 0 && init_addr[index] != 1) { 2468 dbg("calling init function for %s at %p", elm->obj->path, 2469 (void *)init_addr[index]); 2470 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2471 (void *)init_addr[index], 0, 0, elm->obj->path); 2472 call_init_pointer(elm->obj, init_addr[index]); 2473 } 2474 } 2475 } 2476 wlock_acquire(rtld_bind_lock, lockstate); 2477 } 2478 errmsg_restore(saved_msg); 2479} 2480 2481static void 2482objlist_clear(Objlist *list) 2483{ 2484 Objlist_Entry *elm; 2485 2486 while (!STAILQ_EMPTY(list)) { 2487 elm = STAILQ_FIRST(list); 2488 STAILQ_REMOVE_HEAD(list, link); 2489 free(elm); 2490 } 2491} 2492 2493static Objlist_Entry * 2494objlist_find(Objlist *list, const Obj_Entry *obj) 2495{ 2496 Objlist_Entry *elm; 2497 2498 STAILQ_FOREACH(elm, list, link) 2499 if (elm->obj == obj) 2500 return elm; 2501 return NULL; 2502} 2503 2504static void 2505objlist_init(Objlist *list) 2506{ 2507 STAILQ_INIT(list); 2508} 2509 2510static void 2511objlist_push_head(Objlist *list, Obj_Entry *obj) 2512{ 2513 Objlist_Entry *elm; 2514 2515 elm = NEW(Objlist_Entry); 2516 elm->obj = obj; 2517 STAILQ_INSERT_HEAD(list, elm, link); 2518} 2519 2520static void 2521objlist_push_tail(Objlist *list, Obj_Entry *obj) 2522{ 2523 Objlist_Entry *elm; 2524 2525 elm = NEW(Objlist_Entry); 2526 elm->obj = obj; 2527 STAILQ_INSERT_TAIL(list, elm, link); 2528} 2529 2530static void 2531objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2532{ 2533 Objlist_Entry *elm, *listelm; 2534 2535 STAILQ_FOREACH(listelm, list, link) { 2536 if (listelm->obj == listobj) 2537 break; 2538 } 2539 elm = NEW(Objlist_Entry); 2540 elm->obj = obj; 2541 if (listelm != NULL) 2542 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2543 else 2544 STAILQ_INSERT_TAIL(list, elm, link); 2545} 2546 2547static void 2548objlist_remove(Objlist *list, Obj_Entry *obj) 2549{ 2550 Objlist_Entry *elm; 2551 2552 if ((elm = objlist_find(list, obj)) != NULL) { 2553 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2554 free(elm); 2555 } 2556} 2557 2558/* 2559 * Relocate dag rooted in the specified object. 2560 * Returns 0 on success, or -1 on failure. 2561 */ 2562 2563static int 2564relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2565 int flags, RtldLockState *lockstate) 2566{ 2567 Objlist_Entry *elm; 2568 int error; 2569 2570 error = 0; 2571 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2572 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2573 lockstate); 2574 if (error == -1) 2575 break; 2576 } 2577 return (error); 2578} 2579 2580/* 2581 * Prepare for, or clean after, relocating an object marked with 2582 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2583 * segments are remapped read-write. After relocations are done, the 2584 * segment's permissions are returned back to the modes specified in 2585 * the phdrs. If any relocation happened, or always for wired 2586 * program, COW is triggered. 2587 */ 2588static int 2589reloc_textrel_prot(Obj_Entry *obj, bool before) 2590{ 2591 const Elf_Phdr *ph; 2592 void *base; 2593 size_t l, sz; 2594 int prot; 2595 2596 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2597 l--, ph++) { 2598 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2599 continue; 2600 base = obj->relocbase + trunc_page(ph->p_vaddr); 2601 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2602 trunc_page(ph->p_vaddr); 2603 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2604 if (mprotect(base, sz, prot) == -1) { 2605 _rtld_error("%s: Cannot write-%sable text segment: %s", 2606 obj->path, before ? "en" : "dis", 2607 rtld_strerror(errno)); 2608 return (-1); 2609 } 2610 } 2611 return (0); 2612} 2613 2614/* 2615 * Relocate single object. 2616 * Returns 0 on success, or -1 on failure. 2617 */ 2618static int 2619relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2620 int flags, RtldLockState *lockstate) 2621{ 2622 2623 if (obj->relocated) 2624 return (0); 2625 obj->relocated = true; 2626 if (obj != rtldobj) 2627 dbg("relocating \"%s\"", obj->path); 2628 2629 if (obj->symtab == NULL || obj->strtab == NULL || 2630 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2631 _rtld_error("%s: Shared object has no run-time symbol table", 2632 obj->path); 2633 return (-1); 2634 } 2635 2636 /* There are relocations to the write-protected text segment. */ 2637 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2638 return (-1); 2639 2640 /* Process the non-PLT non-IFUNC relocations. */ 2641 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2642 return (-1); 2643 2644 /* Re-protected the text segment. */ 2645 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2646 return (-1); 2647 2648 /* Set the special PLT or GOT entries. */ 2649 init_pltgot(obj); 2650 2651 /* Process the PLT relocations. */ 2652 if (reloc_plt(obj) == -1) 2653 return (-1); 2654 /* Relocate the jump slots if we are doing immediate binding. */ 2655 if (obj->bind_now || bind_now) 2656 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2657 return (-1); 2658 2659 /* 2660 * Process the non-PLT IFUNC relocations. The relocations are 2661 * processed in two phases, because IFUNC resolvers may 2662 * reference other symbols, which must be readily processed 2663 * before resolvers are called. 2664 */ 2665 if (obj->non_plt_gnu_ifunc && 2666 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2667 return (-1); 2668 2669 if (obj->relro_size > 0) { 2670 if (mprotect(obj->relro_page, obj->relro_size, 2671 PROT_READ) == -1) { 2672 _rtld_error("%s: Cannot enforce relro protection: %s", 2673 obj->path, rtld_strerror(errno)); 2674 return (-1); 2675 } 2676 } 2677 2678 /* 2679 * Set up the magic number and version in the Obj_Entry. These 2680 * were checked in the crt1.o from the original ElfKit, so we 2681 * set them for backward compatibility. 2682 */ 2683 obj->magic = RTLD_MAGIC; 2684 obj->version = RTLD_VERSION; 2685 2686 return (0); 2687} 2688 2689/* 2690 * Relocate newly-loaded shared objects. The argument is a pointer to 2691 * the Obj_Entry for the first such object. All objects from the first 2692 * to the end of the list of objects are relocated. Returns 0 on success, 2693 * or -1 on failure. 2694 */ 2695static int 2696relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2697 int flags, RtldLockState *lockstate) 2698{ 2699 Obj_Entry *obj; 2700 int error; 2701 2702 error = 0; 2703 obj = first; 2704 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2705 if (obj->marker) 2706 continue; 2707 error = relocate_object(obj, bind_now, rtldobj, flags, 2708 lockstate); 2709 if (error == -1) 2710 break; 2711 } 2712 return (error); 2713} 2714 2715/* 2716 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2717 * referencing STT_GNU_IFUNC symbols is postponed till the other 2718 * relocations are done. The indirect functions specified as 2719 * ifunc are allowed to call other symbols, so we need to have 2720 * objects relocated before asking for resolution from indirects. 2721 * 2722 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2723 * instead of the usual lazy handling of PLT slots. It is 2724 * consistent with how GNU does it. 2725 */ 2726static int 2727resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2728 RtldLockState *lockstate) 2729{ 2730 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2731 return (-1); 2732 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2733 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2734 return (-1); 2735 return (0); 2736} 2737 2738static int 2739resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2740 RtldLockState *lockstate) 2741{ 2742 Obj_Entry *obj; 2743 2744 obj = first; 2745 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2746 if (obj->marker) 2747 continue; 2748 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2749 return (-1); 2750 } 2751 return (0); 2752} 2753 2754static int 2755initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2756 RtldLockState *lockstate) 2757{ 2758 Objlist_Entry *elm; 2759 2760 STAILQ_FOREACH(elm, list, link) { 2761 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2762 lockstate) == -1) 2763 return (-1); 2764 } 2765 return (0); 2766} 2767 2768/* 2769 * Cleanup procedure. It will be called (by the atexit mechanism) just 2770 * before the process exits. 2771 */ 2772static void 2773rtld_exit(void) 2774{ 2775 RtldLockState lockstate; 2776 2777 wlock_acquire(rtld_bind_lock, &lockstate); 2778 dbg("rtld_exit()"); 2779 objlist_call_fini(&list_fini, NULL, &lockstate); 2780 /* No need to remove the items from the list, since we are exiting. */ 2781 if (!libmap_disable) 2782 lm_fini(); 2783 lock_release(rtld_bind_lock, &lockstate); 2784} 2785 2786/* 2787 * Iterate over a search path, translate each element, and invoke the 2788 * callback on the result. 2789 */ 2790static void * 2791path_enumerate(const char *path, path_enum_proc callback, void *arg) 2792{ 2793 const char *trans; 2794 if (path == NULL) 2795 return (NULL); 2796 2797 path += strspn(path, ":;"); 2798 while (*path != '\0') { 2799 size_t len; 2800 char *res; 2801 2802 len = strcspn(path, ":;"); 2803 trans = lm_findn(NULL, path, len); 2804 if (trans) 2805 res = callback(trans, strlen(trans), arg); 2806 else 2807 res = callback(path, len, arg); 2808 2809 if (res != NULL) 2810 return (res); 2811 2812 path += len; 2813 path += strspn(path, ":;"); 2814 } 2815 2816 return (NULL); 2817} 2818 2819struct try_library_args { 2820 const char *name; 2821 size_t namelen; 2822 char *buffer; 2823 size_t buflen; 2824}; 2825 2826static void * 2827try_library_path(const char *dir, size_t dirlen, void *param) 2828{ 2829 struct try_library_args *arg; 2830 2831 arg = param; 2832 if (*dir == '/' || trust) { 2833 char *pathname; 2834 2835 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2836 return (NULL); 2837 2838 pathname = arg->buffer; 2839 strncpy(pathname, dir, dirlen); 2840 pathname[dirlen] = '/'; 2841 strcpy(pathname + dirlen + 1, arg->name); 2842 2843 dbg(" Trying \"%s\"", pathname); 2844 if (access(pathname, F_OK) == 0) { /* We found it */ 2845 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2846 strcpy(pathname, arg->buffer); 2847 return (pathname); 2848 } 2849 } 2850 return (NULL); 2851} 2852 2853static char * 2854search_library_path(const char *name, const char *path) 2855{ 2856 char *p; 2857 struct try_library_args arg; 2858 2859 if (path == NULL) 2860 return NULL; 2861 2862 arg.name = name; 2863 arg.namelen = strlen(name); 2864 arg.buffer = xmalloc(PATH_MAX); 2865 arg.buflen = PATH_MAX; 2866 2867 p = path_enumerate(path, try_library_path, &arg); 2868 2869 free(arg.buffer); 2870 2871 return (p); 2872} 2873 2874int 2875dlclose(void *handle) 2876{ 2877 Obj_Entry *root; 2878 RtldLockState lockstate; 2879 2880 wlock_acquire(rtld_bind_lock, &lockstate); 2881 root = dlcheck(handle); 2882 if (root == NULL) { 2883 lock_release(rtld_bind_lock, &lockstate); 2884 return -1; 2885 } 2886 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2887 root->path); 2888 2889 /* Unreference the object and its dependencies. */ 2890 root->dl_refcount--; 2891 2892 if (root->refcount == 1) { 2893 /* 2894 * The object will be no longer referenced, so we must unload it. 2895 * First, call the fini functions. 2896 */ 2897 objlist_call_fini(&list_fini, root, &lockstate); 2898 2899 unref_dag(root); 2900 2901 /* Finish cleaning up the newly-unreferenced objects. */ 2902 GDB_STATE(RT_DELETE,&root->linkmap); 2903 unload_object(root); 2904 GDB_STATE(RT_CONSISTENT,NULL); 2905 } else 2906 unref_dag(root); 2907 2908 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2909 lock_release(rtld_bind_lock, &lockstate); 2910 return 0; 2911} 2912 2913char * 2914dlerror(void) 2915{ 2916 char *msg = error_message; 2917 error_message = NULL; 2918 return msg; 2919} 2920 2921/* 2922 * This function is deprecated and has no effect. 2923 */ 2924void 2925dllockinit(void *context, 2926 void *(*lock_create)(void *context), 2927 void (*rlock_acquire)(void *lock), 2928 void (*wlock_acquire)(void *lock), 2929 void (*lock_release)(void *lock), 2930 void (*lock_destroy)(void *lock), 2931 void (*context_destroy)(void *context)) 2932{ 2933 static void *cur_context; 2934 static void (*cur_context_destroy)(void *); 2935 2936 /* Just destroy the context from the previous call, if necessary. */ 2937 if (cur_context_destroy != NULL) 2938 cur_context_destroy(cur_context); 2939 cur_context = context; 2940 cur_context_destroy = context_destroy; 2941} 2942 2943void * 2944dlopen(const char *name, int mode) 2945{ 2946 2947 return (rtld_dlopen(name, -1, mode)); 2948} 2949 2950void * 2951fdlopen(int fd, int mode) 2952{ 2953 2954 return (rtld_dlopen(NULL, fd, mode)); 2955} 2956 2957static void * 2958rtld_dlopen(const char *name, int fd, int mode) 2959{ 2960 RtldLockState lockstate; 2961 int lo_flags; 2962 2963 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2964 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2965 if (ld_tracing != NULL) { 2966 rlock_acquire(rtld_bind_lock, &lockstate); 2967 if (sigsetjmp(lockstate.env, 0) != 0) 2968 lock_upgrade(rtld_bind_lock, &lockstate); 2969 environ = (char **)*get_program_var_addr("environ", &lockstate); 2970 lock_release(rtld_bind_lock, &lockstate); 2971 } 2972 lo_flags = RTLD_LO_DLOPEN; 2973 if (mode & RTLD_NODELETE) 2974 lo_flags |= RTLD_LO_NODELETE; 2975 if (mode & RTLD_NOLOAD) 2976 lo_flags |= RTLD_LO_NOLOAD; 2977 if (ld_tracing != NULL) 2978 lo_flags |= RTLD_LO_TRACE; 2979 2980 return (dlopen_object(name, fd, obj_main, lo_flags, 2981 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2982} 2983 2984static void 2985dlopen_cleanup(Obj_Entry *obj) 2986{ 2987 2988 obj->dl_refcount--; 2989 unref_dag(obj); 2990 if (obj->refcount == 0) 2991 unload_object(obj); 2992} 2993 2994static Obj_Entry * 2995dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2996 int mode, RtldLockState *lockstate) 2997{ 2998 Obj_Entry *old_obj_tail; 2999 Obj_Entry *obj; 3000 Objlist initlist; 3001 RtldLockState mlockstate; 3002 int result; 3003 3004 objlist_init(&initlist); 3005 3006 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3007 wlock_acquire(rtld_bind_lock, &mlockstate); 3008 lockstate = &mlockstate; 3009 } 3010 GDB_STATE(RT_ADD,NULL); 3011 3012 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3013 obj = NULL; 3014 if (name == NULL && fd == -1) { 3015 obj = obj_main; 3016 obj->refcount++; 3017 } else { 3018 obj = load_object(name, fd, refobj, lo_flags); 3019 } 3020 3021 if (obj) { 3022 obj->dl_refcount++; 3023 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3024 objlist_push_tail(&list_global, obj); 3025 if (globallist_next(old_obj_tail) != NULL) { 3026 /* We loaded something new. */ 3027 assert(globallist_next(old_obj_tail) == obj); 3028 result = load_needed_objects(obj, 3029 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3030 init_dag(obj); 3031 ref_dag(obj); 3032 if (result != -1) 3033 result = rtld_verify_versions(&obj->dagmembers); 3034 if (result != -1 && ld_tracing) 3035 goto trace; 3036 if (result == -1 || relocate_object_dag(obj, 3037 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3038 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3039 lockstate) == -1) { 3040 dlopen_cleanup(obj); 3041 obj = NULL; 3042 } else if (lo_flags & RTLD_LO_EARLY) { 3043 /* 3044 * Do not call the init functions for early loaded 3045 * filtees. The image is still not initialized enough 3046 * for them to work. 3047 * 3048 * Our object is found by the global object list and 3049 * will be ordered among all init calls done right 3050 * before transferring control to main. 3051 */ 3052 } else { 3053 /* Make list of init functions to call. */ 3054 initlist_add_objects(obj, obj, &initlist); 3055 } 3056 /* 3057 * Process all no_delete or global objects here, given 3058 * them own DAGs to prevent their dependencies from being 3059 * unloaded. This has to be done after we have loaded all 3060 * of the dependencies, so that we do not miss any. 3061 */ 3062 if (obj != NULL) 3063 process_z(obj); 3064 } else { 3065 /* 3066 * Bump the reference counts for objects on this DAG. If 3067 * this is the first dlopen() call for the object that was 3068 * already loaded as a dependency, initialize the dag 3069 * starting at it. 3070 */ 3071 init_dag(obj); 3072 ref_dag(obj); 3073 3074 if ((lo_flags & RTLD_LO_TRACE) != 0) 3075 goto trace; 3076 } 3077 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3078 obj->z_nodelete) && !obj->ref_nodel) { 3079 dbg("obj %s nodelete", obj->path); 3080 ref_dag(obj); 3081 obj->z_nodelete = obj->ref_nodel = true; 3082 } 3083 } 3084 3085 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3086 name); 3087 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3088 3089 if (!(lo_flags & RTLD_LO_EARLY)) { 3090 map_stacks_exec(lockstate); 3091 } 3092 3093 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3094 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3095 lockstate) == -1) { 3096 objlist_clear(&initlist); 3097 dlopen_cleanup(obj); 3098 if (lockstate == &mlockstate) 3099 lock_release(rtld_bind_lock, lockstate); 3100 return (NULL); 3101 } 3102 3103 if (!(lo_flags & RTLD_LO_EARLY)) { 3104 /* Call the init functions. */ 3105 objlist_call_init(&initlist, lockstate); 3106 } 3107 objlist_clear(&initlist); 3108 if (lockstate == &mlockstate) 3109 lock_release(rtld_bind_lock, lockstate); 3110 return obj; 3111trace: 3112 trace_loaded_objects(obj); 3113 if (lockstate == &mlockstate) 3114 lock_release(rtld_bind_lock, lockstate); 3115 exit(0); 3116} 3117 3118static void * 3119do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3120 int flags) 3121{ 3122 DoneList donelist; 3123 const Obj_Entry *obj, *defobj; 3124 const Elf_Sym *def; 3125 SymLook req; 3126 RtldLockState lockstate; 3127#ifndef __ia64__ 3128 tls_index ti; 3129#endif 3130 void *sym; 3131 int res; 3132 3133 def = NULL; 3134 defobj = NULL; 3135 symlook_init(&req, name); 3136 req.ventry = ve; 3137 req.flags = flags | SYMLOOK_IN_PLT; 3138 req.lockstate = &lockstate; 3139 3140 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3141 rlock_acquire(rtld_bind_lock, &lockstate); 3142 if (sigsetjmp(lockstate.env, 0) != 0) 3143 lock_upgrade(rtld_bind_lock, &lockstate); 3144 if (handle == NULL || handle == RTLD_NEXT || 3145 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3146 3147 if ((obj = obj_from_addr(retaddr)) == NULL) { 3148 _rtld_error("Cannot determine caller's shared object"); 3149 lock_release(rtld_bind_lock, &lockstate); 3150 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3151 return NULL; 3152 } 3153 if (handle == NULL) { /* Just the caller's shared object. */ 3154 res = symlook_obj(&req, obj); 3155 if (res == 0) { 3156 def = req.sym_out; 3157 defobj = req.defobj_out; 3158 } 3159 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3160 handle == RTLD_SELF) { /* ... caller included */ 3161 if (handle == RTLD_NEXT) 3162 obj = globallist_next(obj); 3163 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 3164 if (obj->marker) 3165 continue; 3166 res = symlook_obj(&req, obj); 3167 if (res == 0) { 3168 if (def == NULL || 3169 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3170 def = req.sym_out; 3171 defobj = req.defobj_out; 3172 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3173 break; 3174 } 3175 } 3176 } 3177 /* 3178 * Search the dynamic linker itself, and possibly resolve the 3179 * symbol from there. This is how the application links to 3180 * dynamic linker services such as dlopen. 3181 */ 3182 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3183 res = symlook_obj(&req, &obj_rtld); 3184 if (res == 0) { 3185 def = req.sym_out; 3186 defobj = req.defobj_out; 3187 } 3188 } 3189 } else { 3190 assert(handle == RTLD_DEFAULT); 3191 res = symlook_default(&req, obj); 3192 if (res == 0) { 3193 defobj = req.defobj_out; 3194 def = req.sym_out; 3195 } 3196 } 3197 } else { 3198 if ((obj = dlcheck(handle)) == NULL) { 3199 lock_release(rtld_bind_lock, &lockstate); 3200 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3201 return NULL; 3202 } 3203 3204 donelist_init(&donelist); 3205 if (obj->mainprog) { 3206 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3207 res = symlook_global(&req, &donelist); 3208 if (res == 0) { 3209 def = req.sym_out; 3210 defobj = req.defobj_out; 3211 } 3212 /* 3213 * Search the dynamic linker itself, and possibly resolve the 3214 * symbol from there. This is how the application links to 3215 * dynamic linker services such as dlopen. 3216 */ 3217 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3218 res = symlook_obj(&req, &obj_rtld); 3219 if (res == 0) { 3220 def = req.sym_out; 3221 defobj = req.defobj_out; 3222 } 3223 } 3224 } 3225 else { 3226 /* Search the whole DAG rooted at the given object. */ 3227 res = symlook_list(&req, &obj->dagmembers, &donelist); 3228 if (res == 0) { 3229 def = req.sym_out; 3230 defobj = req.defobj_out; 3231 } 3232 } 3233 } 3234 3235 if (def != NULL) { 3236 lock_release(rtld_bind_lock, &lockstate); 3237 3238 /* 3239 * The value required by the caller is derived from the value 3240 * of the symbol. For the ia64 architecture, we need to 3241 * construct a function descriptor which the caller can use to 3242 * call the function with the right 'gp' value. For other 3243 * architectures and for non-functions, the value is simply 3244 * the relocated value of the symbol. 3245 */ 3246 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3247 sym = make_function_pointer(def, defobj); 3248 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3249 sym = rtld_resolve_ifunc(defobj, def); 3250 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3251#ifdef __ia64__ 3252 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3253#else 3254 ti.ti_module = defobj->tlsindex; 3255 ti.ti_offset = def->st_value; 3256 sym = __tls_get_addr(&ti); 3257#endif 3258 } else 3259 sym = defobj->relocbase + def->st_value; 3260 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3261 return (sym); 3262 } 3263 3264 _rtld_error("Undefined symbol \"%s\"", name); 3265 lock_release(rtld_bind_lock, &lockstate); 3266 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3267 return NULL; 3268} 3269 3270void * 3271dlsym(void *handle, const char *name) 3272{ 3273 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3274 SYMLOOK_DLSYM); 3275} 3276 3277dlfunc_t 3278dlfunc(void *handle, const char *name) 3279{ 3280 union { 3281 void *d; 3282 dlfunc_t f; 3283 } rv; 3284 3285 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3286 SYMLOOK_DLSYM); 3287 return (rv.f); 3288} 3289 3290void * 3291dlvsym(void *handle, const char *name, const char *version) 3292{ 3293 Ver_Entry ventry; 3294 3295 ventry.name = version; 3296 ventry.file = NULL; 3297 ventry.hash = elf_hash(version); 3298 ventry.flags= 0; 3299 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3300 SYMLOOK_DLSYM); 3301} 3302 3303int 3304_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3305{ 3306 const Obj_Entry *obj; 3307 RtldLockState lockstate; 3308 3309 rlock_acquire(rtld_bind_lock, &lockstate); 3310 obj = obj_from_addr(addr); 3311 if (obj == NULL) { 3312 _rtld_error("No shared object contains address"); 3313 lock_release(rtld_bind_lock, &lockstate); 3314 return (0); 3315 } 3316 rtld_fill_dl_phdr_info(obj, phdr_info); 3317 lock_release(rtld_bind_lock, &lockstate); 3318 return (1); 3319} 3320 3321int 3322dladdr(const void *addr, Dl_info *info) 3323{ 3324 const Obj_Entry *obj; 3325 const Elf_Sym *def; 3326 void *symbol_addr; 3327 unsigned long symoffset; 3328 RtldLockState lockstate; 3329 3330 rlock_acquire(rtld_bind_lock, &lockstate); 3331 obj = obj_from_addr(addr); 3332 if (obj == NULL) { 3333 _rtld_error("No shared object contains address"); 3334 lock_release(rtld_bind_lock, &lockstate); 3335 return 0; 3336 } 3337 info->dli_fname = obj->path; 3338 info->dli_fbase = obj->mapbase; 3339 info->dli_saddr = (void *)0; 3340 info->dli_sname = NULL; 3341 3342 /* 3343 * Walk the symbol list looking for the symbol whose address is 3344 * closest to the address sent in. 3345 */ 3346 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3347 def = obj->symtab + symoffset; 3348 3349 /* 3350 * For skip the symbol if st_shndx is either SHN_UNDEF or 3351 * SHN_COMMON. 3352 */ 3353 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3354 continue; 3355 3356 /* 3357 * If the symbol is greater than the specified address, or if it 3358 * is further away from addr than the current nearest symbol, 3359 * then reject it. 3360 */ 3361 symbol_addr = obj->relocbase + def->st_value; 3362 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3363 continue; 3364 3365 /* Update our idea of the nearest symbol. */ 3366 info->dli_sname = obj->strtab + def->st_name; 3367 info->dli_saddr = symbol_addr; 3368 3369 /* Exact match? */ 3370 if (info->dli_saddr == addr) 3371 break; 3372 } 3373 lock_release(rtld_bind_lock, &lockstate); 3374 return 1; 3375} 3376 3377int 3378dlinfo(void *handle, int request, void *p) 3379{ 3380 const Obj_Entry *obj; 3381 RtldLockState lockstate; 3382 int error; 3383 3384 rlock_acquire(rtld_bind_lock, &lockstate); 3385 3386 if (handle == NULL || handle == RTLD_SELF) { 3387 void *retaddr; 3388 3389 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3390 if ((obj = obj_from_addr(retaddr)) == NULL) 3391 _rtld_error("Cannot determine caller's shared object"); 3392 } else 3393 obj = dlcheck(handle); 3394 3395 if (obj == NULL) { 3396 lock_release(rtld_bind_lock, &lockstate); 3397 return (-1); 3398 } 3399 3400 error = 0; 3401 switch (request) { 3402 case RTLD_DI_LINKMAP: 3403 *((struct link_map const **)p) = &obj->linkmap; 3404 break; 3405 case RTLD_DI_ORIGIN: 3406 error = rtld_dirname(obj->path, p); 3407 break; 3408 3409 case RTLD_DI_SERINFOSIZE: 3410 case RTLD_DI_SERINFO: 3411 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3412 break; 3413 3414 default: 3415 _rtld_error("Invalid request %d passed to dlinfo()", request); 3416 error = -1; 3417 } 3418 3419 lock_release(rtld_bind_lock, &lockstate); 3420 3421 return (error); 3422} 3423 3424static void 3425rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3426{ 3427 3428 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3429 phdr_info->dlpi_name = obj->path; 3430 phdr_info->dlpi_phdr = obj->phdr; 3431 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3432 phdr_info->dlpi_tls_modid = obj->tlsindex; 3433 phdr_info->dlpi_tls_data = obj->tlsinit; 3434 phdr_info->dlpi_adds = obj_loads; 3435 phdr_info->dlpi_subs = obj_loads - obj_count; 3436} 3437 3438int 3439dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3440{ 3441 struct dl_phdr_info phdr_info; 3442 Obj_Entry *obj, marker; 3443 RtldLockState bind_lockstate, phdr_lockstate; 3444 int error; 3445 3446 bzero(&marker, sizeof(marker)); 3447 marker.marker = true; 3448 error = 0; 3449 3450 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3451 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3452 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3453 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3454 rtld_fill_dl_phdr_info(obj, &phdr_info); 3455 lock_release(rtld_bind_lock, &bind_lockstate); 3456 3457 error = callback(&phdr_info, sizeof phdr_info, param); 3458 3459 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3460 obj = globallist_next(&marker); 3461 TAILQ_REMOVE(&obj_list, &marker, next); 3462 if (error != 0) { 3463 lock_release(rtld_bind_lock, &bind_lockstate); 3464 lock_release(rtld_phdr_lock, &phdr_lockstate); 3465 return (error); 3466 } 3467 } 3468 3469 if (error == 0) { 3470 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3471 lock_release(rtld_bind_lock, &bind_lockstate); 3472 error = callback(&phdr_info, sizeof(phdr_info), param); 3473 } 3474 lock_release(rtld_phdr_lock, &phdr_lockstate); 3475 return (error); 3476} 3477 3478static void * 3479fill_search_info(const char *dir, size_t dirlen, void *param) 3480{ 3481 struct fill_search_info_args *arg; 3482 3483 arg = param; 3484 3485 if (arg->request == RTLD_DI_SERINFOSIZE) { 3486 arg->serinfo->dls_cnt ++; 3487 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3488 } else { 3489 struct dl_serpath *s_entry; 3490 3491 s_entry = arg->serpath; 3492 s_entry->dls_name = arg->strspace; 3493 s_entry->dls_flags = arg->flags; 3494 3495 strncpy(arg->strspace, dir, dirlen); 3496 arg->strspace[dirlen] = '\0'; 3497 3498 arg->strspace += dirlen + 1; 3499 arg->serpath++; 3500 } 3501 3502 return (NULL); 3503} 3504 3505static int 3506do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3507{ 3508 struct dl_serinfo _info; 3509 struct fill_search_info_args args; 3510 3511 args.request = RTLD_DI_SERINFOSIZE; 3512 args.serinfo = &_info; 3513 3514 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3515 _info.dls_cnt = 0; 3516 3517 path_enumerate(obj->rpath, fill_search_info, &args); 3518 path_enumerate(ld_library_path, fill_search_info, &args); 3519 path_enumerate(obj->runpath, fill_search_info, &args); 3520 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3521 if (!obj->z_nodeflib) 3522 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3523 3524 3525 if (request == RTLD_DI_SERINFOSIZE) { 3526 info->dls_size = _info.dls_size; 3527 info->dls_cnt = _info.dls_cnt; 3528 return (0); 3529 } 3530 3531 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3532 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3533 return (-1); 3534 } 3535 3536 args.request = RTLD_DI_SERINFO; 3537 args.serinfo = info; 3538 args.serpath = &info->dls_serpath[0]; 3539 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3540 3541 args.flags = LA_SER_RUNPATH; 3542 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3543 return (-1); 3544 3545 args.flags = LA_SER_LIBPATH; 3546 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3547 return (-1); 3548 3549 args.flags = LA_SER_RUNPATH; 3550 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3551 return (-1); 3552 3553 args.flags = LA_SER_CONFIG; 3554 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3555 != NULL) 3556 return (-1); 3557 3558 args.flags = LA_SER_DEFAULT; 3559 if (!obj->z_nodeflib && 3560 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3561 return (-1); 3562 return (0); 3563} 3564 3565static int 3566rtld_dirname(const char *path, char *bname) 3567{ 3568 const char *endp; 3569 3570 /* Empty or NULL string gets treated as "." */ 3571 if (path == NULL || *path == '\0') { 3572 bname[0] = '.'; 3573 bname[1] = '\0'; 3574 return (0); 3575 } 3576 3577 /* Strip trailing slashes */ 3578 endp = path + strlen(path) - 1; 3579 while (endp > path && *endp == '/') 3580 endp--; 3581 3582 /* Find the start of the dir */ 3583 while (endp > path && *endp != '/') 3584 endp--; 3585 3586 /* Either the dir is "/" or there are no slashes */ 3587 if (endp == path) { 3588 bname[0] = *endp == '/' ? '/' : '.'; 3589 bname[1] = '\0'; 3590 return (0); 3591 } else { 3592 do { 3593 endp--; 3594 } while (endp > path && *endp == '/'); 3595 } 3596 3597 if (endp - path + 2 > PATH_MAX) 3598 { 3599 _rtld_error("Filename is too long: %s", path); 3600 return(-1); 3601 } 3602 3603 strncpy(bname, path, endp - path + 1); 3604 bname[endp - path + 1] = '\0'; 3605 return (0); 3606} 3607 3608static int 3609rtld_dirname_abs(const char *path, char *base) 3610{ 3611 char *last; 3612 3613 if (realpath(path, base) == NULL) 3614 return (-1); 3615 dbg("%s -> %s", path, base); 3616 last = strrchr(base, '/'); 3617 if (last == NULL) 3618 return (-1); 3619 if (last != base) 3620 *last = '\0'; 3621 return (0); 3622} 3623 3624static void 3625linkmap_add(Obj_Entry *obj) 3626{ 3627 struct link_map *l = &obj->linkmap; 3628 struct link_map *prev; 3629 3630 obj->linkmap.l_name = obj->path; 3631 obj->linkmap.l_addr = obj->mapbase; 3632 obj->linkmap.l_ld = obj->dynamic; 3633#ifdef __mips__ 3634 /* GDB needs load offset on MIPS to use the symbols */ 3635 obj->linkmap.l_offs = obj->relocbase; 3636#endif 3637 3638 if (r_debug.r_map == NULL) { 3639 r_debug.r_map = l; 3640 return; 3641 } 3642 3643 /* 3644 * Scan to the end of the list, but not past the entry for the 3645 * dynamic linker, which we want to keep at the very end. 3646 */ 3647 for (prev = r_debug.r_map; 3648 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3649 prev = prev->l_next) 3650 ; 3651 3652 /* Link in the new entry. */ 3653 l->l_prev = prev; 3654 l->l_next = prev->l_next; 3655 if (l->l_next != NULL) 3656 l->l_next->l_prev = l; 3657 prev->l_next = l; 3658} 3659 3660static void 3661linkmap_delete(Obj_Entry *obj) 3662{ 3663 struct link_map *l = &obj->linkmap; 3664 3665 if (l->l_prev == NULL) { 3666 if ((r_debug.r_map = l->l_next) != NULL) 3667 l->l_next->l_prev = NULL; 3668 return; 3669 } 3670 3671 if ((l->l_prev->l_next = l->l_next) != NULL) 3672 l->l_next->l_prev = l->l_prev; 3673} 3674 3675/* 3676 * Function for the debugger to set a breakpoint on to gain control. 3677 * 3678 * The two parameters allow the debugger to easily find and determine 3679 * what the runtime loader is doing and to whom it is doing it. 3680 * 3681 * When the loadhook trap is hit (r_debug_state, set at program 3682 * initialization), the arguments can be found on the stack: 3683 * 3684 * +8 struct link_map *m 3685 * +4 struct r_debug *rd 3686 * +0 RetAddr 3687 */ 3688void 3689r_debug_state(struct r_debug* rd, struct link_map *m) 3690{ 3691 /* 3692 * The following is a hack to force the compiler to emit calls to 3693 * this function, even when optimizing. If the function is empty, 3694 * the compiler is not obliged to emit any code for calls to it, 3695 * even when marked __noinline. However, gdb depends on those 3696 * calls being made. 3697 */ 3698 __compiler_membar(); 3699} 3700 3701/* 3702 * A function called after init routines have completed. This can be used to 3703 * break before a program's entry routine is called, and can be used when 3704 * main is not available in the symbol table. 3705 */ 3706void 3707_r_debug_postinit(struct link_map *m) 3708{ 3709 3710 /* See r_debug_state(). */ 3711 __compiler_membar(); 3712} 3713 3714/* 3715 * Get address of the pointer variable in the main program. 3716 * Prefer non-weak symbol over the weak one. 3717 */ 3718static const void ** 3719get_program_var_addr(const char *name, RtldLockState *lockstate) 3720{ 3721 SymLook req; 3722 DoneList donelist; 3723 3724 symlook_init(&req, name); 3725 req.lockstate = lockstate; 3726 donelist_init(&donelist); 3727 if (symlook_global(&req, &donelist) != 0) 3728 return (NULL); 3729 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3730 return ((const void **)make_function_pointer(req.sym_out, 3731 req.defobj_out)); 3732 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3733 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3734 else 3735 return ((const void **)(req.defobj_out->relocbase + 3736 req.sym_out->st_value)); 3737} 3738 3739/* 3740 * Set a pointer variable in the main program to the given value. This 3741 * is used to set key variables such as "environ" before any of the 3742 * init functions are called. 3743 */ 3744static void 3745set_program_var(const char *name, const void *value) 3746{ 3747 const void **addr; 3748 3749 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3750 dbg("\"%s\": *%p <-- %p", name, addr, value); 3751 *addr = value; 3752 } 3753} 3754 3755/* 3756 * Search the global objects, including dependencies and main object, 3757 * for the given symbol. 3758 */ 3759static int 3760symlook_global(SymLook *req, DoneList *donelist) 3761{ 3762 SymLook req1; 3763 const Objlist_Entry *elm; 3764 int res; 3765 3766 symlook_init_from_req(&req1, req); 3767 3768 /* Search all objects loaded at program start up. */ 3769 if (req->defobj_out == NULL || 3770 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3771 res = symlook_list(&req1, &list_main, donelist); 3772 if (res == 0 && (req->defobj_out == NULL || 3773 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3774 req->sym_out = req1.sym_out; 3775 req->defobj_out = req1.defobj_out; 3776 assert(req->defobj_out != NULL); 3777 } 3778 } 3779 3780 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3781 STAILQ_FOREACH(elm, &list_global, link) { 3782 if (req->defobj_out != NULL && 3783 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3784 break; 3785 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3786 if (res == 0 && (req->defobj_out == NULL || 3787 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3788 req->sym_out = req1.sym_out; 3789 req->defobj_out = req1.defobj_out; 3790 assert(req->defobj_out != NULL); 3791 } 3792 } 3793 3794 return (req->sym_out != NULL ? 0 : ESRCH); 3795} 3796 3797/* 3798 * Given a symbol name in a referencing object, find the corresponding 3799 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3800 * no definition was found. Returns a pointer to the Obj_Entry of the 3801 * defining object via the reference parameter DEFOBJ_OUT. 3802 */ 3803static int 3804symlook_default(SymLook *req, const Obj_Entry *refobj) 3805{ 3806 DoneList donelist; 3807 const Objlist_Entry *elm; 3808 SymLook req1; 3809 int res; 3810 3811 donelist_init(&donelist); 3812 symlook_init_from_req(&req1, req); 3813 3814 /* Look first in the referencing object if linked symbolically. */ 3815 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3816 res = symlook_obj(&req1, refobj); 3817 if (res == 0) { 3818 req->sym_out = req1.sym_out; 3819 req->defobj_out = req1.defobj_out; 3820 assert(req->defobj_out != NULL); 3821 } 3822 } 3823 3824 symlook_global(req, &donelist); 3825 3826 /* Search all dlopened DAGs containing the referencing object. */ 3827 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3828 if (req->sym_out != NULL && 3829 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3830 break; 3831 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3832 if (res == 0 && (req->sym_out == NULL || 3833 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3834 req->sym_out = req1.sym_out; 3835 req->defobj_out = req1.defobj_out; 3836 assert(req->defobj_out != NULL); 3837 } 3838 } 3839 3840 /* 3841 * Search the dynamic linker itself, and possibly resolve the 3842 * symbol from there. This is how the application links to 3843 * dynamic linker services such as dlopen. 3844 */ 3845 if (req->sym_out == NULL || 3846 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3847 res = symlook_obj(&req1, &obj_rtld); 3848 if (res == 0) { 3849 req->sym_out = req1.sym_out; 3850 req->defobj_out = req1.defobj_out; 3851 assert(req->defobj_out != NULL); 3852 } 3853 } 3854 3855 return (req->sym_out != NULL ? 0 : ESRCH); 3856} 3857 3858static int 3859symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3860{ 3861 const Elf_Sym *def; 3862 const Obj_Entry *defobj; 3863 const Objlist_Entry *elm; 3864 SymLook req1; 3865 int res; 3866 3867 def = NULL; 3868 defobj = NULL; 3869 STAILQ_FOREACH(elm, objlist, link) { 3870 if (donelist_check(dlp, elm->obj)) 3871 continue; 3872 symlook_init_from_req(&req1, req); 3873 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3874 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3875 def = req1.sym_out; 3876 defobj = req1.defobj_out; 3877 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3878 break; 3879 } 3880 } 3881 } 3882 if (def != NULL) { 3883 req->sym_out = def; 3884 req->defobj_out = defobj; 3885 return (0); 3886 } 3887 return (ESRCH); 3888} 3889 3890/* 3891 * Search the chain of DAGS cointed to by the given Needed_Entry 3892 * for a symbol of the given name. Each DAG is scanned completely 3893 * before advancing to the next one. Returns a pointer to the symbol, 3894 * or NULL if no definition was found. 3895 */ 3896static int 3897symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3898{ 3899 const Elf_Sym *def; 3900 const Needed_Entry *n; 3901 const Obj_Entry *defobj; 3902 SymLook req1; 3903 int res; 3904 3905 def = NULL; 3906 defobj = NULL; 3907 symlook_init_from_req(&req1, req); 3908 for (n = needed; n != NULL; n = n->next) { 3909 if (n->obj == NULL || 3910 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3911 continue; 3912 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3913 def = req1.sym_out; 3914 defobj = req1.defobj_out; 3915 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3916 break; 3917 } 3918 } 3919 if (def != NULL) { 3920 req->sym_out = def; 3921 req->defobj_out = defobj; 3922 return (0); 3923 } 3924 return (ESRCH); 3925} 3926 3927/* 3928 * Search the symbol table of a single shared object for a symbol of 3929 * the given name and version, if requested. Returns a pointer to the 3930 * symbol, or NULL if no definition was found. If the object is 3931 * filter, return filtered symbol from filtee. 3932 * 3933 * The symbol's hash value is passed in for efficiency reasons; that 3934 * eliminates many recomputations of the hash value. 3935 */ 3936int 3937symlook_obj(SymLook *req, const Obj_Entry *obj) 3938{ 3939 DoneList donelist; 3940 SymLook req1; 3941 int flags, res, mres; 3942 3943 /* 3944 * If there is at least one valid hash at this point, we prefer to 3945 * use the faster GNU version if available. 3946 */ 3947 if (obj->valid_hash_gnu) 3948 mres = symlook_obj1_gnu(req, obj); 3949 else if (obj->valid_hash_sysv) 3950 mres = symlook_obj1_sysv(req, obj); 3951 else 3952 return (EINVAL); 3953 3954 if (mres == 0) { 3955 if (obj->needed_filtees != NULL) { 3956 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3957 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3958 donelist_init(&donelist); 3959 symlook_init_from_req(&req1, req); 3960 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3961 if (res == 0) { 3962 req->sym_out = req1.sym_out; 3963 req->defobj_out = req1.defobj_out; 3964 } 3965 return (res); 3966 } 3967 if (obj->needed_aux_filtees != NULL) { 3968 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3969 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3970 donelist_init(&donelist); 3971 symlook_init_from_req(&req1, req); 3972 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3973 if (res == 0) { 3974 req->sym_out = req1.sym_out; 3975 req->defobj_out = req1.defobj_out; 3976 return (res); 3977 } 3978 } 3979 } 3980 return (mres); 3981} 3982 3983/* Symbol match routine common to both hash functions */ 3984static bool 3985matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3986 const unsigned long symnum) 3987{ 3988 Elf_Versym verndx; 3989 const Elf_Sym *symp; 3990 const char *strp; 3991 3992 symp = obj->symtab + symnum; 3993 strp = obj->strtab + symp->st_name; 3994 3995 switch (ELF_ST_TYPE(symp->st_info)) { 3996 case STT_FUNC: 3997 case STT_NOTYPE: 3998 case STT_OBJECT: 3999 case STT_COMMON: 4000 case STT_GNU_IFUNC: 4001 if (symp->st_value == 0) 4002 return (false); 4003 /* fallthrough */ 4004 case STT_TLS: 4005 if (symp->st_shndx != SHN_UNDEF) 4006 break; 4007#ifndef __mips__ 4008 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4009 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4010 break; 4011 /* fallthrough */ 4012#endif 4013 default: 4014 return (false); 4015 } 4016 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4017 return (false); 4018 4019 if (req->ventry == NULL) { 4020 if (obj->versyms != NULL) { 4021 verndx = VER_NDX(obj->versyms[symnum]); 4022 if (verndx > obj->vernum) { 4023 _rtld_error( 4024 "%s: symbol %s references wrong version %d", 4025 obj->path, obj->strtab + symnum, verndx); 4026 return (false); 4027 } 4028 /* 4029 * If we are not called from dlsym (i.e. this 4030 * is a normal relocation from unversioned 4031 * binary), accept the symbol immediately if 4032 * it happens to have first version after this 4033 * shared object became versioned. Otherwise, 4034 * if symbol is versioned and not hidden, 4035 * remember it. If it is the only symbol with 4036 * this name exported by the shared object, it 4037 * will be returned as a match by the calling 4038 * function. If symbol is global (verndx < 2) 4039 * accept it unconditionally. 4040 */ 4041 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4042 verndx == VER_NDX_GIVEN) { 4043 result->sym_out = symp; 4044 return (true); 4045 } 4046 else if (verndx >= VER_NDX_GIVEN) { 4047 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4048 == 0) { 4049 if (result->vsymp == NULL) 4050 result->vsymp = symp; 4051 result->vcount++; 4052 } 4053 return (false); 4054 } 4055 } 4056 result->sym_out = symp; 4057 return (true); 4058 } 4059 if (obj->versyms == NULL) { 4060 if (object_match_name(obj, req->ventry->name)) { 4061 _rtld_error("%s: object %s should provide version %s " 4062 "for symbol %s", obj_rtld.path, obj->path, 4063 req->ventry->name, obj->strtab + symnum); 4064 return (false); 4065 } 4066 } else { 4067 verndx = VER_NDX(obj->versyms[symnum]); 4068 if (verndx > obj->vernum) { 4069 _rtld_error("%s: symbol %s references wrong version %d", 4070 obj->path, obj->strtab + symnum, verndx); 4071 return (false); 4072 } 4073 if (obj->vertab[verndx].hash != req->ventry->hash || 4074 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4075 /* 4076 * Version does not match. Look if this is a 4077 * global symbol and if it is not hidden. If 4078 * global symbol (verndx < 2) is available, 4079 * use it. Do not return symbol if we are 4080 * called by dlvsym, because dlvsym looks for 4081 * a specific version and default one is not 4082 * what dlvsym wants. 4083 */ 4084 if ((req->flags & SYMLOOK_DLSYM) || 4085 (verndx >= VER_NDX_GIVEN) || 4086 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4087 return (false); 4088 } 4089 } 4090 result->sym_out = symp; 4091 return (true); 4092} 4093 4094/* 4095 * Search for symbol using SysV hash function. 4096 * obj->buckets is known not to be NULL at this point; the test for this was 4097 * performed with the obj->valid_hash_sysv assignment. 4098 */ 4099static int 4100symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4101{ 4102 unsigned long symnum; 4103 Sym_Match_Result matchres; 4104 4105 matchres.sym_out = NULL; 4106 matchres.vsymp = NULL; 4107 matchres.vcount = 0; 4108 4109 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4110 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4111 if (symnum >= obj->nchains) 4112 return (ESRCH); /* Bad object */ 4113 4114 if (matched_symbol(req, obj, &matchres, symnum)) { 4115 req->sym_out = matchres.sym_out; 4116 req->defobj_out = obj; 4117 return (0); 4118 } 4119 } 4120 if (matchres.vcount == 1) { 4121 req->sym_out = matchres.vsymp; 4122 req->defobj_out = obj; 4123 return (0); 4124 } 4125 return (ESRCH); 4126} 4127 4128/* Search for symbol using GNU hash function */ 4129static int 4130symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4131{ 4132 Elf_Addr bloom_word; 4133 const Elf32_Word *hashval; 4134 Elf32_Word bucket; 4135 Sym_Match_Result matchres; 4136 unsigned int h1, h2; 4137 unsigned long symnum; 4138 4139 matchres.sym_out = NULL; 4140 matchres.vsymp = NULL; 4141 matchres.vcount = 0; 4142 4143 /* Pick right bitmask word from Bloom filter array */ 4144 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4145 obj->maskwords_bm_gnu]; 4146 4147 /* Calculate modulus word size of gnu hash and its derivative */ 4148 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4149 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4150 4151 /* Filter out the "definitely not in set" queries */ 4152 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4153 return (ESRCH); 4154 4155 /* Locate hash chain and corresponding value element*/ 4156 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4157 if (bucket == 0) 4158 return (ESRCH); 4159 hashval = &obj->chain_zero_gnu[bucket]; 4160 do { 4161 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4162 symnum = hashval - obj->chain_zero_gnu; 4163 if (matched_symbol(req, obj, &matchres, symnum)) { 4164 req->sym_out = matchres.sym_out; 4165 req->defobj_out = obj; 4166 return (0); 4167 } 4168 } 4169 } while ((*hashval++ & 1) == 0); 4170 if (matchres.vcount == 1) { 4171 req->sym_out = matchres.vsymp; 4172 req->defobj_out = obj; 4173 return (0); 4174 } 4175 return (ESRCH); 4176} 4177 4178static void 4179trace_loaded_objects(Obj_Entry *obj) 4180{ 4181 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4182 int c; 4183 4184 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4185 main_local = ""; 4186 4187 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4188 fmt1 = "\t%o => %p (%x)\n"; 4189 4190 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4191 fmt2 = "\t%o (%x)\n"; 4192 4193 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4194 4195 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4196 Needed_Entry *needed; 4197 char *name, *path; 4198 bool is_lib; 4199 4200 if (obj->marker) 4201 continue; 4202 if (list_containers && obj->needed != NULL) 4203 rtld_printf("%s:\n", obj->path); 4204 for (needed = obj->needed; needed; needed = needed->next) { 4205 if (needed->obj != NULL) { 4206 if (needed->obj->traced && !list_containers) 4207 continue; 4208 needed->obj->traced = true; 4209 path = needed->obj->path; 4210 } else 4211 path = "not found"; 4212 4213 name = (char *)obj->strtab + needed->name; 4214 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4215 4216 fmt = is_lib ? fmt1 : fmt2; 4217 while ((c = *fmt++) != '\0') { 4218 switch (c) { 4219 default: 4220 rtld_putchar(c); 4221 continue; 4222 case '\\': 4223 switch (c = *fmt) { 4224 case '\0': 4225 continue; 4226 case 'n': 4227 rtld_putchar('\n'); 4228 break; 4229 case 't': 4230 rtld_putchar('\t'); 4231 break; 4232 } 4233 break; 4234 case '%': 4235 switch (c = *fmt) { 4236 case '\0': 4237 continue; 4238 case '%': 4239 default: 4240 rtld_putchar(c); 4241 break; 4242 case 'A': 4243 rtld_putstr(main_local); 4244 break; 4245 case 'a': 4246 rtld_putstr(obj_main->path); 4247 break; 4248 case 'o': 4249 rtld_putstr(name); 4250 break; 4251#if 0 4252 case 'm': 4253 rtld_printf("%d", sodp->sod_major); 4254 break; 4255 case 'n': 4256 rtld_printf("%d", sodp->sod_minor); 4257 break; 4258#endif 4259 case 'p': 4260 rtld_putstr(path); 4261 break; 4262 case 'x': 4263 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4264 0); 4265 break; 4266 } 4267 break; 4268 } 4269 ++fmt; 4270 } 4271 } 4272 } 4273} 4274 4275/* 4276 * Unload a dlopened object and its dependencies from memory and from 4277 * our data structures. It is assumed that the DAG rooted in the 4278 * object has already been unreferenced, and that the object has a 4279 * reference count of 0. 4280 */ 4281static void 4282unload_object(Obj_Entry *root) 4283{ 4284 Obj_Entry *obj, *obj1; 4285 4286 assert(root->refcount == 0); 4287 4288 /* 4289 * Pass over the DAG removing unreferenced objects from 4290 * appropriate lists. 4291 */ 4292 unlink_object(root); 4293 4294 /* Unmap all objects that are no longer referenced. */ 4295 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4296 if (obj->marker || obj->refcount != 0) 4297 continue; 4298 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4299 obj->mapsize, 0, obj->path); 4300 dbg("unloading \"%s\"", obj->path); 4301 unload_filtees(root); 4302 munmap(obj->mapbase, obj->mapsize); 4303 linkmap_delete(obj); 4304 TAILQ_REMOVE(&obj_list, obj, next); 4305 obj_count--; 4306 obj_free(obj); 4307 } 4308} 4309 4310static void 4311unlink_object(Obj_Entry *root) 4312{ 4313 Objlist_Entry *elm; 4314 4315 if (root->refcount == 0) { 4316 /* Remove the object from the RTLD_GLOBAL list. */ 4317 objlist_remove(&list_global, root); 4318 4319 /* Remove the object from all objects' DAG lists. */ 4320 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4321 objlist_remove(&elm->obj->dldags, root); 4322 if (elm->obj != root) 4323 unlink_object(elm->obj); 4324 } 4325 } 4326} 4327 4328static void 4329ref_dag(Obj_Entry *root) 4330{ 4331 Objlist_Entry *elm; 4332 4333 assert(root->dag_inited); 4334 STAILQ_FOREACH(elm, &root->dagmembers, link) 4335 elm->obj->refcount++; 4336} 4337 4338static void 4339unref_dag(Obj_Entry *root) 4340{ 4341 Objlist_Entry *elm; 4342 4343 assert(root->dag_inited); 4344 STAILQ_FOREACH(elm, &root->dagmembers, link) 4345 elm->obj->refcount--; 4346} 4347 4348/* 4349 * Common code for MD __tls_get_addr(). 4350 */ 4351static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4352static void * 4353tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4354{ 4355 Elf_Addr *newdtv, *dtv; 4356 RtldLockState lockstate; 4357 int to_copy; 4358 4359 dtv = *dtvp; 4360 /* Check dtv generation in case new modules have arrived */ 4361 if (dtv[0] != tls_dtv_generation) { 4362 wlock_acquire(rtld_bind_lock, &lockstate); 4363 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4364 to_copy = dtv[1]; 4365 if (to_copy > tls_max_index) 4366 to_copy = tls_max_index; 4367 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4368 newdtv[0] = tls_dtv_generation; 4369 newdtv[1] = tls_max_index; 4370 free(dtv); 4371 lock_release(rtld_bind_lock, &lockstate); 4372 dtv = *dtvp = newdtv; 4373 } 4374 4375 /* Dynamically allocate module TLS if necessary */ 4376 if (dtv[index + 1] == 0) { 4377 /* Signal safe, wlock will block out signals. */ 4378 wlock_acquire(rtld_bind_lock, &lockstate); 4379 if (!dtv[index + 1]) 4380 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4381 lock_release(rtld_bind_lock, &lockstate); 4382 } 4383 return ((void *)(dtv[index + 1] + offset)); 4384} 4385 4386void * 4387tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4388{ 4389 Elf_Addr *dtv; 4390 4391 dtv = *dtvp; 4392 /* Check dtv generation in case new modules have arrived */ 4393 if (__predict_true(dtv[0] == tls_dtv_generation && 4394 dtv[index + 1] != 0)) 4395 return ((void *)(dtv[index + 1] + offset)); 4396 return (tls_get_addr_slow(dtvp, index, offset)); 4397} 4398 4399#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4400 4401/* 4402 * Allocate Static TLS using the Variant I method. 4403 */ 4404void * 4405allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4406{ 4407 Obj_Entry *obj; 4408 char *tcb; 4409 Elf_Addr **tls; 4410 Elf_Addr *dtv; 4411 Elf_Addr addr; 4412 int i; 4413 4414 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4415 return (oldtcb); 4416 4417 assert(tcbsize >= TLS_TCB_SIZE); 4418 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4419 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4420 4421 if (oldtcb != NULL) { 4422 memcpy(tls, oldtcb, tls_static_space); 4423 free(oldtcb); 4424 4425 /* Adjust the DTV. */ 4426 dtv = tls[0]; 4427 for (i = 0; i < dtv[1]; i++) { 4428 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4429 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4430 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4431 } 4432 } 4433 } else { 4434 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4435 tls[0] = dtv; 4436 dtv[0] = tls_dtv_generation; 4437 dtv[1] = tls_max_index; 4438 4439 for (obj = globallist_curr(objs); obj != NULL; 4440 obj = globallist_next(obj)) { 4441 if (obj->tlsoffset > 0) { 4442 addr = (Elf_Addr)tls + obj->tlsoffset; 4443 if (obj->tlsinitsize > 0) 4444 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4445 if (obj->tlssize > obj->tlsinitsize) 4446 memset((void*) (addr + obj->tlsinitsize), 0, 4447 obj->tlssize - obj->tlsinitsize); 4448 dtv[obj->tlsindex + 1] = addr; 4449 } 4450 } 4451 } 4452 4453 return (tcb); 4454} 4455 4456void 4457free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4458{ 4459 Elf_Addr *dtv; 4460 Elf_Addr tlsstart, tlsend; 4461 int dtvsize, i; 4462 4463 assert(tcbsize >= TLS_TCB_SIZE); 4464 4465 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4466 tlsend = tlsstart + tls_static_space; 4467 4468 dtv = *(Elf_Addr **)tlsstart; 4469 dtvsize = dtv[1]; 4470 for (i = 0; i < dtvsize; i++) { 4471 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4472 free((void*)dtv[i+2]); 4473 } 4474 } 4475 free(dtv); 4476 free(tcb); 4477} 4478 4479#endif 4480 4481#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4482 4483/* 4484 * Allocate Static TLS using the Variant II method. 4485 */ 4486void * 4487allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4488{ 4489 Obj_Entry *obj; 4490 size_t size, ralign; 4491 char *tls; 4492 Elf_Addr *dtv, *olddtv; 4493 Elf_Addr segbase, oldsegbase, addr; 4494 int i; 4495 4496 ralign = tcbalign; 4497 if (tls_static_max_align > ralign) 4498 ralign = tls_static_max_align; 4499 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4500 4501 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4502 tls = malloc_aligned(size, ralign); 4503 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4504 4505 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4506 ((Elf_Addr*)segbase)[0] = segbase; 4507 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4508 4509 dtv[0] = tls_dtv_generation; 4510 dtv[1] = tls_max_index; 4511 4512 if (oldtls) { 4513 /* 4514 * Copy the static TLS block over whole. 4515 */ 4516 oldsegbase = (Elf_Addr) oldtls; 4517 memcpy((void *)(segbase - tls_static_space), 4518 (const void *)(oldsegbase - tls_static_space), 4519 tls_static_space); 4520 4521 /* 4522 * If any dynamic TLS blocks have been created tls_get_addr(), 4523 * move them over. 4524 */ 4525 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4526 for (i = 0; i < olddtv[1]; i++) { 4527 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4528 dtv[i+2] = olddtv[i+2]; 4529 olddtv[i+2] = 0; 4530 } 4531 } 4532 4533 /* 4534 * We assume that this block was the one we created with 4535 * allocate_initial_tls(). 4536 */ 4537 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4538 } else { 4539 obj = objs; 4540 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4541 if (obj->marker || obj->tlsoffset == 0) 4542 continue; 4543 addr = segbase - obj->tlsoffset; 4544 memset((void*) (addr + obj->tlsinitsize), 4545 0, obj->tlssize - obj->tlsinitsize); 4546 if (obj->tlsinit) 4547 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4548 dtv[obj->tlsindex + 1] = addr; 4549 } 4550 } 4551 4552 return (void*) segbase; 4553} 4554 4555void 4556free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4557{ 4558 Elf_Addr* dtv; 4559 size_t size, ralign; 4560 int dtvsize, i; 4561 Elf_Addr tlsstart, tlsend; 4562 4563 /* 4564 * Figure out the size of the initial TLS block so that we can 4565 * find stuff which ___tls_get_addr() allocated dynamically. 4566 */ 4567 ralign = tcbalign; 4568 if (tls_static_max_align > ralign) 4569 ralign = tls_static_max_align; 4570 size = round(tls_static_space, ralign); 4571 4572 dtv = ((Elf_Addr**)tls)[1]; 4573 dtvsize = dtv[1]; 4574 tlsend = (Elf_Addr) tls; 4575 tlsstart = tlsend - size; 4576 for (i = 0; i < dtvsize; i++) { 4577 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4578 free_aligned((void *)dtv[i + 2]); 4579 } 4580 } 4581 4582 free_aligned((void *)tlsstart); 4583 free((void*) dtv); 4584} 4585 4586#endif 4587 4588/* 4589 * Allocate TLS block for module with given index. 4590 */ 4591void * 4592allocate_module_tls(int index) 4593{ 4594 Obj_Entry* obj; 4595 char* p; 4596 4597 TAILQ_FOREACH(obj, &obj_list, next) { 4598 if (obj->marker) 4599 continue; 4600 if (obj->tlsindex == index) 4601 break; 4602 } 4603 if (!obj) { 4604 _rtld_error("Can't find module with TLS index %d", index); 4605 rtld_die(); 4606 } 4607 4608 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4609 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4610 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4611 4612 return p; 4613} 4614 4615bool 4616allocate_tls_offset(Obj_Entry *obj) 4617{ 4618 size_t off; 4619 4620 if (obj->tls_done) 4621 return true; 4622 4623 if (obj->tlssize == 0) { 4624 obj->tls_done = true; 4625 return true; 4626 } 4627 4628 if (tls_last_offset == 0) 4629 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4630 else 4631 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4632 obj->tlssize, obj->tlsalign); 4633 4634 /* 4635 * If we have already fixed the size of the static TLS block, we 4636 * must stay within that size. When allocating the static TLS, we 4637 * leave a small amount of space spare to be used for dynamically 4638 * loading modules which use static TLS. 4639 */ 4640 if (tls_static_space != 0) { 4641 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4642 return false; 4643 } else if (obj->tlsalign > tls_static_max_align) { 4644 tls_static_max_align = obj->tlsalign; 4645 } 4646 4647 tls_last_offset = obj->tlsoffset = off; 4648 tls_last_size = obj->tlssize; 4649 obj->tls_done = true; 4650 4651 return true; 4652} 4653 4654void 4655free_tls_offset(Obj_Entry *obj) 4656{ 4657 4658 /* 4659 * If we were the last thing to allocate out of the static TLS 4660 * block, we give our space back to the 'allocator'. This is a 4661 * simplistic workaround to allow libGL.so.1 to be loaded and 4662 * unloaded multiple times. 4663 */ 4664 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4665 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4666 tls_last_offset -= obj->tlssize; 4667 tls_last_size = 0; 4668 } 4669} 4670 4671void * 4672_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4673{ 4674 void *ret; 4675 RtldLockState lockstate; 4676 4677 wlock_acquire(rtld_bind_lock, &lockstate); 4678 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4679 tcbsize, tcbalign); 4680 lock_release(rtld_bind_lock, &lockstate); 4681 return (ret); 4682} 4683 4684void 4685_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4686{ 4687 RtldLockState lockstate; 4688 4689 wlock_acquire(rtld_bind_lock, &lockstate); 4690 free_tls(tcb, tcbsize, tcbalign); 4691 lock_release(rtld_bind_lock, &lockstate); 4692} 4693 4694static void 4695object_add_name(Obj_Entry *obj, const char *name) 4696{ 4697 Name_Entry *entry; 4698 size_t len; 4699 4700 len = strlen(name); 4701 entry = malloc(sizeof(Name_Entry) + len); 4702 4703 if (entry != NULL) { 4704 strcpy(entry->name, name); 4705 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4706 } 4707} 4708 4709static int 4710object_match_name(const Obj_Entry *obj, const char *name) 4711{ 4712 Name_Entry *entry; 4713 4714 STAILQ_FOREACH(entry, &obj->names, link) { 4715 if (strcmp(name, entry->name) == 0) 4716 return (1); 4717 } 4718 return (0); 4719} 4720 4721static Obj_Entry * 4722locate_dependency(const Obj_Entry *obj, const char *name) 4723{ 4724 const Objlist_Entry *entry; 4725 const Needed_Entry *needed; 4726 4727 STAILQ_FOREACH(entry, &list_main, link) { 4728 if (object_match_name(entry->obj, name)) 4729 return entry->obj; 4730 } 4731 4732 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4733 if (strcmp(obj->strtab + needed->name, name) == 0 || 4734 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4735 /* 4736 * If there is DT_NEEDED for the name we are looking for, 4737 * we are all set. Note that object might not be found if 4738 * dependency was not loaded yet, so the function can 4739 * return NULL here. This is expected and handled 4740 * properly by the caller. 4741 */ 4742 return (needed->obj); 4743 } 4744 } 4745 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4746 obj->path, name); 4747 rtld_die(); 4748} 4749 4750static int 4751check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4752 const Elf_Vernaux *vna) 4753{ 4754 const Elf_Verdef *vd; 4755 const char *vername; 4756 4757 vername = refobj->strtab + vna->vna_name; 4758 vd = depobj->verdef; 4759 if (vd == NULL) { 4760 _rtld_error("%s: version %s required by %s not defined", 4761 depobj->path, vername, refobj->path); 4762 return (-1); 4763 } 4764 for (;;) { 4765 if (vd->vd_version != VER_DEF_CURRENT) { 4766 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4767 depobj->path, vd->vd_version); 4768 return (-1); 4769 } 4770 if (vna->vna_hash == vd->vd_hash) { 4771 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4772 ((char *)vd + vd->vd_aux); 4773 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4774 return (0); 4775 } 4776 if (vd->vd_next == 0) 4777 break; 4778 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4779 } 4780 if (vna->vna_flags & VER_FLG_WEAK) 4781 return (0); 4782 _rtld_error("%s: version %s required by %s not found", 4783 depobj->path, vername, refobj->path); 4784 return (-1); 4785} 4786 4787static int 4788rtld_verify_object_versions(Obj_Entry *obj) 4789{ 4790 const Elf_Verneed *vn; 4791 const Elf_Verdef *vd; 4792 const Elf_Verdaux *vda; 4793 const Elf_Vernaux *vna; 4794 const Obj_Entry *depobj; 4795 int maxvernum, vernum; 4796 4797 if (obj->ver_checked) 4798 return (0); 4799 obj->ver_checked = true; 4800 4801 maxvernum = 0; 4802 /* 4803 * Walk over defined and required version records and figure out 4804 * max index used by any of them. Do very basic sanity checking 4805 * while there. 4806 */ 4807 vn = obj->verneed; 4808 while (vn != NULL) { 4809 if (vn->vn_version != VER_NEED_CURRENT) { 4810 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4811 obj->path, vn->vn_version); 4812 return (-1); 4813 } 4814 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4815 for (;;) { 4816 vernum = VER_NEED_IDX(vna->vna_other); 4817 if (vernum > maxvernum) 4818 maxvernum = vernum; 4819 if (vna->vna_next == 0) 4820 break; 4821 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4822 } 4823 if (vn->vn_next == 0) 4824 break; 4825 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4826 } 4827 4828 vd = obj->verdef; 4829 while (vd != NULL) { 4830 if (vd->vd_version != VER_DEF_CURRENT) { 4831 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4832 obj->path, vd->vd_version); 4833 return (-1); 4834 } 4835 vernum = VER_DEF_IDX(vd->vd_ndx); 4836 if (vernum > maxvernum) 4837 maxvernum = vernum; 4838 if (vd->vd_next == 0) 4839 break; 4840 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4841 } 4842 4843 if (maxvernum == 0) 4844 return (0); 4845 4846 /* 4847 * Store version information in array indexable by version index. 4848 * Verify that object version requirements are satisfied along the 4849 * way. 4850 */ 4851 obj->vernum = maxvernum + 1; 4852 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4853 4854 vd = obj->verdef; 4855 while (vd != NULL) { 4856 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4857 vernum = VER_DEF_IDX(vd->vd_ndx); 4858 assert(vernum <= maxvernum); 4859 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4860 obj->vertab[vernum].hash = vd->vd_hash; 4861 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4862 obj->vertab[vernum].file = NULL; 4863 obj->vertab[vernum].flags = 0; 4864 } 4865 if (vd->vd_next == 0) 4866 break; 4867 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4868 } 4869 4870 vn = obj->verneed; 4871 while (vn != NULL) { 4872 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4873 if (depobj == NULL) 4874 return (-1); 4875 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4876 for (;;) { 4877 if (check_object_provided_version(obj, depobj, vna)) 4878 return (-1); 4879 vernum = VER_NEED_IDX(vna->vna_other); 4880 assert(vernum <= maxvernum); 4881 obj->vertab[vernum].hash = vna->vna_hash; 4882 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4883 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4884 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4885 VER_INFO_HIDDEN : 0; 4886 if (vna->vna_next == 0) 4887 break; 4888 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4889 } 4890 if (vn->vn_next == 0) 4891 break; 4892 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4893 } 4894 return 0; 4895} 4896 4897static int 4898rtld_verify_versions(const Objlist *objlist) 4899{ 4900 Objlist_Entry *entry; 4901 int rc; 4902 4903 rc = 0; 4904 STAILQ_FOREACH(entry, objlist, link) { 4905 /* 4906 * Skip dummy objects or objects that have their version requirements 4907 * already checked. 4908 */ 4909 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4910 continue; 4911 if (rtld_verify_object_versions(entry->obj) == -1) { 4912 rc = -1; 4913 if (ld_tracing == NULL) 4914 break; 4915 } 4916 } 4917 if (rc == 0 || ld_tracing != NULL) 4918 rc = rtld_verify_object_versions(&obj_rtld); 4919 return rc; 4920} 4921 4922const Ver_Entry * 4923fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4924{ 4925 Elf_Versym vernum; 4926 4927 if (obj->vertab) { 4928 vernum = VER_NDX(obj->versyms[symnum]); 4929 if (vernum >= obj->vernum) { 4930 _rtld_error("%s: symbol %s has wrong verneed value %d", 4931 obj->path, obj->strtab + symnum, vernum); 4932 } else if (obj->vertab[vernum].hash != 0) { 4933 return &obj->vertab[vernum]; 4934 } 4935 } 4936 return NULL; 4937} 4938 4939int 4940_rtld_get_stack_prot(void) 4941{ 4942 4943 return (stack_prot); 4944} 4945 4946int 4947_rtld_is_dlopened(void *arg) 4948{ 4949 Obj_Entry *obj; 4950 RtldLockState lockstate; 4951 int res; 4952 4953 rlock_acquire(rtld_bind_lock, &lockstate); 4954 obj = dlcheck(arg); 4955 if (obj == NULL) 4956 obj = obj_from_addr(arg); 4957 if (obj == NULL) { 4958 _rtld_error("No shared object contains address"); 4959 lock_release(rtld_bind_lock, &lockstate); 4960 return (-1); 4961 } 4962 res = obj->dlopened ? 1 : 0; 4963 lock_release(rtld_bind_lock, &lockstate); 4964 return (res); 4965} 4966 4967static void 4968map_stacks_exec(RtldLockState *lockstate) 4969{ 4970 void (*thr_map_stacks_exec)(void); 4971 4972 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4973 return; 4974 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4975 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4976 if (thr_map_stacks_exec != NULL) { 4977 stack_prot |= PROT_EXEC; 4978 thr_map_stacks_exec(); 4979 } 4980} 4981 4982void 4983symlook_init(SymLook *dst, const char *name) 4984{ 4985 4986 bzero(dst, sizeof(*dst)); 4987 dst->name = name; 4988 dst->hash = elf_hash(name); 4989 dst->hash_gnu = gnu_hash(name); 4990} 4991 4992static void 4993symlook_init_from_req(SymLook *dst, const SymLook *src) 4994{ 4995 4996 dst->name = src->name; 4997 dst->hash = src->hash; 4998 dst->hash_gnu = src->hash_gnu; 4999 dst->ventry = src->ventry; 5000 dst->flags = src->flags; 5001 dst->defobj_out = NULL; 5002 dst->sym_out = NULL; 5003 dst->lockstate = src->lockstate; 5004} 5005 5006/* 5007 * Overrides for libc_pic-provided functions. 5008 */ 5009 5010int 5011__getosreldate(void) 5012{ 5013 size_t len; 5014 int oid[2]; 5015 int error, osrel; 5016 5017 if (osreldate != 0) 5018 return (osreldate); 5019 5020 oid[0] = CTL_KERN; 5021 oid[1] = KERN_OSRELDATE; 5022 osrel = 0; 5023 len = sizeof(osrel); 5024 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5025 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5026 osreldate = osrel; 5027 return (osreldate); 5028} 5029 5030void 5031exit(int status) 5032{ 5033 5034 _exit(status); 5035} 5036 5037void (*__cleanup)(void); 5038int __isthreaded = 0; 5039int _thread_autoinit_dummy_decl = 1; 5040 5041/* 5042 * No unresolved symbols for rtld. 5043 */ 5044void 5045__pthread_cxa_finalize(struct dl_phdr_info *a) 5046{ 5047} 5048 5049void 5050__stack_chk_fail(void) 5051{ 5052 5053 _rtld_error("stack overflow detected; terminated"); 5054 rtld_die(); 5055} 5056__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5057 5058void 5059__chk_fail(void) 5060{ 5061 5062 _rtld_error("buffer overflow detected; terminated"); 5063 rtld_die(); 5064} 5065 5066const char * 5067rtld_strerror(int errnum) 5068{ 5069 5070 if (errnum < 0 || errnum >= sys_nerr) 5071 return ("Unknown error"); 5072 return (sys_errlist[errnum]); 5073} 5074