rtld.c revision 303169
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 303169 2016-07-22 00:43:32Z bdrewery $ 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 static 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 struct stat hint_stat; 1632 unsigned int SLPndx, hintndx, fndx, fcount; 1633 int fd; 1634 size_t flen; 1635 uint32_t dl; 1636 bool skip; 1637 1638 /* First call, read the hints file */ 1639 if (hints == NULL) { 1640 /* Keep from trying again in case the hints file is bad. */ 1641 hints = ""; 1642 1643 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1644 return (NULL); 1645 1646 /* 1647 * Check of hdr.dirlistlen value against type limit 1648 * intends to pacify static analyzers. Further 1649 * paranoia leads to checks that dirlist is fully 1650 * contained in the file range. 1651 */ 1652 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1653 hdr.magic != ELFHINTS_MAGIC || 1654 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1655 fstat(fd, &hint_stat) == -1) { 1656cleanup1: 1657 close(fd); 1658 hdr.dirlistlen = 0; 1659 return (NULL); 1660 } 1661 dl = hdr.strtab; 1662 if (dl + hdr.dirlist < dl) 1663 goto cleanup1; 1664 dl += hdr.dirlist; 1665 if (dl + hdr.dirlistlen < dl) 1666 goto cleanup1; 1667 dl += hdr.dirlistlen; 1668 if (dl > hint_stat.st_size) 1669 goto cleanup1; 1670 p = xmalloc(hdr.dirlistlen + 1); 1671 1672 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1673 read(fd, p, hdr.dirlistlen + 1) != 1674 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1675 free(p); 1676 goto cleanup1; 1677 } 1678 hints = p; 1679 close(fd); 1680 } 1681 1682 /* 1683 * If caller agreed to receive list which includes the default 1684 * paths, we are done. Otherwise, if we still did not 1685 * calculated filtered result, do it now. 1686 */ 1687 if (!nostdlib) 1688 return (hints[0] != '\0' ? hints : NULL); 1689 if (filtered_path != NULL) 1690 goto filt_ret; 1691 1692 /* 1693 * Obtain the list of all configured search paths, and the 1694 * list of the default paths. 1695 * 1696 * First estimate the size of the results. 1697 */ 1698 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1699 smeta.dls_cnt = 0; 1700 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1701 hmeta.dls_cnt = 0; 1702 1703 sargs.request = RTLD_DI_SERINFOSIZE; 1704 sargs.serinfo = &smeta; 1705 hargs.request = RTLD_DI_SERINFOSIZE; 1706 hargs.serinfo = &hmeta; 1707 1708 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1709 path_enumerate(hints, fill_search_info, &hargs); 1710 1711 SLPinfo = xmalloc(smeta.dls_size); 1712 hintinfo = xmalloc(hmeta.dls_size); 1713 1714 /* 1715 * Next fetch both sets of paths. 1716 */ 1717 sargs.request = RTLD_DI_SERINFO; 1718 sargs.serinfo = SLPinfo; 1719 sargs.serpath = &SLPinfo->dls_serpath[0]; 1720 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1721 1722 hargs.request = RTLD_DI_SERINFO; 1723 hargs.serinfo = hintinfo; 1724 hargs.serpath = &hintinfo->dls_serpath[0]; 1725 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1726 1727 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1728 path_enumerate(hints, fill_search_info, &hargs); 1729 1730 /* 1731 * Now calculate the difference between two sets, by excluding 1732 * standard paths from the full set. 1733 */ 1734 fndx = 0; 1735 fcount = 0; 1736 filtered_path = xmalloc(hdr.dirlistlen + 1); 1737 hintpath = &hintinfo->dls_serpath[0]; 1738 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1739 skip = false; 1740 SLPpath = &SLPinfo->dls_serpath[0]; 1741 /* 1742 * Check each standard path against current. 1743 */ 1744 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1745 /* matched, skip the path */ 1746 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1747 skip = true; 1748 break; 1749 } 1750 } 1751 if (skip) 1752 continue; 1753 /* 1754 * Not matched against any standard path, add the path 1755 * to result. Separate consequtive paths with ':'. 1756 */ 1757 if (fcount > 0) { 1758 filtered_path[fndx] = ':'; 1759 fndx++; 1760 } 1761 fcount++; 1762 flen = strlen(hintpath->dls_name); 1763 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1764 fndx += flen; 1765 } 1766 filtered_path[fndx] = '\0'; 1767 1768 free(SLPinfo); 1769 free(hintinfo); 1770 1771filt_ret: 1772 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1773} 1774 1775static void 1776init_dag(Obj_Entry *root) 1777{ 1778 const Needed_Entry *needed; 1779 const Objlist_Entry *elm; 1780 DoneList donelist; 1781 1782 if (root->dag_inited) 1783 return; 1784 donelist_init(&donelist); 1785 1786 /* Root object belongs to own DAG. */ 1787 objlist_push_tail(&root->dldags, root); 1788 objlist_push_tail(&root->dagmembers, root); 1789 donelist_check(&donelist, root); 1790 1791 /* 1792 * Add dependencies of root object to DAG in breadth order 1793 * by exploiting the fact that each new object get added 1794 * to the tail of the dagmembers list. 1795 */ 1796 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1797 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1798 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1799 continue; 1800 objlist_push_tail(&needed->obj->dldags, root); 1801 objlist_push_tail(&root->dagmembers, needed->obj); 1802 } 1803 } 1804 root->dag_inited = true; 1805} 1806 1807Obj_Entry * 1808globallist_curr(const Obj_Entry *obj) 1809{ 1810 1811 for (;;) { 1812 if (obj == NULL) 1813 return (NULL); 1814 if (!obj->marker) 1815 return (__DECONST(Obj_Entry *, obj)); 1816 obj = TAILQ_PREV(obj, obj_entry_q, next); 1817 } 1818} 1819 1820Obj_Entry * 1821globallist_next(const Obj_Entry *obj) 1822{ 1823 1824 for (;;) { 1825 obj = TAILQ_NEXT(obj, next); 1826 if (obj == NULL) 1827 return (NULL); 1828 if (!obj->marker) 1829 return (__DECONST(Obj_Entry *, obj)); 1830 } 1831} 1832 1833static void 1834process_z(Obj_Entry *root) 1835{ 1836 const Objlist_Entry *elm; 1837 Obj_Entry *obj; 1838 1839 /* 1840 * Walk over object DAG and process every dependent object 1841 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1842 * to grow their own DAG. 1843 * 1844 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1845 * symlook_global() to work. 1846 * 1847 * For DF_1_NODELETE, the DAG should have its reference upped. 1848 */ 1849 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1850 obj = elm->obj; 1851 if (obj == NULL) 1852 continue; 1853 if (obj->z_nodelete && !obj->ref_nodel) { 1854 dbg("obj %s -z nodelete", obj->path); 1855 init_dag(obj); 1856 ref_dag(obj); 1857 obj->ref_nodel = true; 1858 } 1859 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1860 dbg("obj %s -z global", obj->path); 1861 objlist_push_tail(&list_global, obj); 1862 init_dag(obj); 1863 } 1864 } 1865} 1866/* 1867 * Initialize the dynamic linker. The argument is the address at which 1868 * the dynamic linker has been mapped into memory. The primary task of 1869 * this function is to relocate the dynamic linker. 1870 */ 1871static void 1872init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1873{ 1874 Obj_Entry objtmp; /* Temporary rtld object */ 1875 const Elf_Dyn *dyn_rpath; 1876 const Elf_Dyn *dyn_soname; 1877 const Elf_Dyn *dyn_runpath; 1878 1879#ifdef RTLD_INIT_PAGESIZES_EARLY 1880 /* The page size is required by the dynamic memory allocator. */ 1881 init_pagesizes(aux_info); 1882#endif 1883 1884 /* 1885 * Conjure up an Obj_Entry structure for the dynamic linker. 1886 * 1887 * The "path" member can't be initialized yet because string constants 1888 * cannot yet be accessed. Below we will set it correctly. 1889 */ 1890 memset(&objtmp, 0, sizeof(objtmp)); 1891 objtmp.path = NULL; 1892 objtmp.rtld = true; 1893 objtmp.mapbase = mapbase; 1894#ifdef PIC 1895 objtmp.relocbase = mapbase; 1896#endif 1897 if (RTLD_IS_DYNAMIC()) { 1898 objtmp.dynamic = rtld_dynamic(&objtmp); 1899 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1900 assert(objtmp.needed == NULL); 1901#if !defined(__mips__) 1902 /* MIPS has a bogus DT_TEXTREL. */ 1903 assert(!objtmp.textrel); 1904#endif 1905 1906 /* 1907 * Temporarily put the dynamic linker entry into the object list, so 1908 * that symbols can be found. 1909 */ 1910 1911 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1912 } 1913 1914 /* Initialize the object list. */ 1915 TAILQ_INIT(&obj_list); 1916 1917 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1918 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1919 1920#ifndef RTLD_INIT_PAGESIZES_EARLY 1921 /* The page size is required by the dynamic memory allocator. */ 1922 init_pagesizes(aux_info); 1923#endif 1924 1925 if (aux_info[AT_OSRELDATE] != NULL) 1926 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1927 1928 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1929 1930 /* Replace the path with a dynamically allocated copy. */ 1931 obj_rtld.path = xstrdup(PATH_RTLD); 1932 1933 r_debug.r_brk = r_debug_state; 1934 r_debug.r_state = RT_CONSISTENT; 1935} 1936 1937/* 1938 * Retrieve the array of supported page sizes. The kernel provides the page 1939 * sizes in increasing order. 1940 */ 1941static void 1942init_pagesizes(Elf_Auxinfo **aux_info) 1943{ 1944 static size_t psa[MAXPAGESIZES]; 1945 int mib[2]; 1946 size_t len, size; 1947 1948 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1949 NULL) { 1950 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1951 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1952 } else { 1953 len = 2; 1954 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1955 size = sizeof(psa); 1956 else { 1957 /* As a fallback, retrieve the base page size. */ 1958 size = sizeof(psa[0]); 1959 if (aux_info[AT_PAGESZ] != NULL) { 1960 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1961 goto psa_filled; 1962 } else { 1963 mib[0] = CTL_HW; 1964 mib[1] = HW_PAGESIZE; 1965 len = 2; 1966 } 1967 } 1968 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1969 _rtld_error("sysctl for hw.pagesize(s) failed"); 1970 rtld_die(); 1971 } 1972psa_filled: 1973 pagesizes = psa; 1974 } 1975 npagesizes = size / sizeof(pagesizes[0]); 1976 /* Discard any invalid entries at the end of the array. */ 1977 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1978 npagesizes--; 1979} 1980 1981/* 1982 * Add the init functions from a needed object list (and its recursive 1983 * needed objects) to "list". This is not used directly; it is a helper 1984 * function for initlist_add_objects(). The write lock must be held 1985 * when this function is called. 1986 */ 1987static void 1988initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1989{ 1990 /* Recursively process the successor needed objects. */ 1991 if (needed->next != NULL) 1992 initlist_add_neededs(needed->next, list); 1993 1994 /* Process the current needed object. */ 1995 if (needed->obj != NULL) 1996 initlist_add_objects(needed->obj, needed->obj, list); 1997} 1998 1999/* 2000 * Scan all of the DAGs rooted in the range of objects from "obj" to 2001 * "tail" and add their init functions to "list". This recurses over 2002 * the DAGs and ensure the proper init ordering such that each object's 2003 * needed libraries are initialized before the object itself. At the 2004 * same time, this function adds the objects to the global finalization 2005 * list "list_fini" in the opposite order. The write lock must be 2006 * held when this function is called. 2007 */ 2008static void 2009initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2010{ 2011 Obj_Entry *nobj; 2012 2013 if (obj->init_scanned || obj->init_done) 2014 return; 2015 obj->init_scanned = true; 2016 2017 /* Recursively process the successor objects. */ 2018 nobj = globallist_next(obj); 2019 if (nobj != NULL && obj != tail) 2020 initlist_add_objects(nobj, tail, list); 2021 2022 /* Recursively process the needed objects. */ 2023 if (obj->needed != NULL) 2024 initlist_add_neededs(obj->needed, list); 2025 if (obj->needed_filtees != NULL) 2026 initlist_add_neededs(obj->needed_filtees, list); 2027 if (obj->needed_aux_filtees != NULL) 2028 initlist_add_neededs(obj->needed_aux_filtees, list); 2029 2030 /* Add the object to the init list. */ 2031 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2032 obj->init_array != (Elf_Addr)NULL) 2033 objlist_push_tail(list, obj); 2034 2035 /* Add the object to the global fini list in the reverse order. */ 2036 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2037 && !obj->on_fini_list) { 2038 objlist_push_head(&list_fini, obj); 2039 obj->on_fini_list = true; 2040 } 2041} 2042 2043#ifndef FPTR_TARGET 2044#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2045#endif 2046 2047static void 2048free_needed_filtees(Needed_Entry *n) 2049{ 2050 Needed_Entry *needed, *needed1; 2051 2052 for (needed = n; needed != NULL; needed = needed->next) { 2053 if (needed->obj != NULL) { 2054 dlclose(needed->obj); 2055 needed->obj = NULL; 2056 } 2057 } 2058 for (needed = n; needed != NULL; needed = needed1) { 2059 needed1 = needed->next; 2060 free(needed); 2061 } 2062} 2063 2064static void 2065unload_filtees(Obj_Entry *obj) 2066{ 2067 2068 free_needed_filtees(obj->needed_filtees); 2069 obj->needed_filtees = NULL; 2070 free_needed_filtees(obj->needed_aux_filtees); 2071 obj->needed_aux_filtees = NULL; 2072 obj->filtees_loaded = false; 2073} 2074 2075static void 2076load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2077 RtldLockState *lockstate) 2078{ 2079 2080 for (; needed != NULL; needed = needed->next) { 2081 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2082 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2083 RTLD_LOCAL, lockstate); 2084 } 2085} 2086 2087static void 2088load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2089{ 2090 2091 lock_restart_for_upgrade(lockstate); 2092 if (!obj->filtees_loaded) { 2093 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2094 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2095 obj->filtees_loaded = true; 2096 } 2097} 2098 2099static int 2100process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2101{ 2102 Obj_Entry *obj1; 2103 2104 for (; needed != NULL; needed = needed->next) { 2105 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2106 flags & ~RTLD_LO_NOLOAD); 2107 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2108 return (-1); 2109 } 2110 return (0); 2111} 2112 2113/* 2114 * Given a shared object, traverse its list of needed objects, and load 2115 * each of them. Returns 0 on success. Generates an error message and 2116 * returns -1 on failure. 2117 */ 2118static int 2119load_needed_objects(Obj_Entry *first, int flags) 2120{ 2121 Obj_Entry *obj; 2122 2123 obj = first; 2124 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2125 if (obj->marker) 2126 continue; 2127 if (process_needed(obj, obj->needed, flags) == -1) 2128 return (-1); 2129 } 2130 return (0); 2131} 2132 2133static int 2134load_preload_objects(void) 2135{ 2136 char *p = ld_preload; 2137 Obj_Entry *obj; 2138 static const char delim[] = " \t:;"; 2139 2140 if (p == NULL) 2141 return 0; 2142 2143 p += strspn(p, delim); 2144 while (*p != '\0') { 2145 size_t len = strcspn(p, delim); 2146 char savech; 2147 2148 savech = p[len]; 2149 p[len] = '\0'; 2150 obj = load_object(p, -1, NULL, 0); 2151 if (obj == NULL) 2152 return -1; /* XXX - cleanup */ 2153 obj->z_interpose = true; 2154 p[len] = savech; 2155 p += len; 2156 p += strspn(p, delim); 2157 } 2158 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2159 return 0; 2160} 2161 2162static const char * 2163printable_path(const char *path) 2164{ 2165 2166 return (path == NULL ? "<unknown>" : path); 2167} 2168 2169/* 2170 * Load a shared object into memory, if it is not already loaded. The 2171 * object may be specified by name or by user-supplied file descriptor 2172 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2173 * duplicate is. 2174 * 2175 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2176 * on failure. 2177 */ 2178static Obj_Entry * 2179load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2180{ 2181 Obj_Entry *obj; 2182 int fd; 2183 struct stat sb; 2184 char *path; 2185 2186 if (name != NULL) { 2187 TAILQ_FOREACH(obj, &obj_list, next) { 2188 if (obj->marker) 2189 continue; 2190 if (object_match_name(obj, name)) 2191 return (obj); 2192 } 2193 2194 path = find_library(name, refobj); 2195 if (path == NULL) 2196 return (NULL); 2197 } else 2198 path = NULL; 2199 2200 /* 2201 * If we didn't find a match by pathname, or the name is not 2202 * supplied, open the file and check again by device and inode. 2203 * This avoids false mismatches caused by multiple links or ".." 2204 * in pathnames. 2205 * 2206 * To avoid a race, we open the file and use fstat() rather than 2207 * using stat(). 2208 */ 2209 fd = -1; 2210 if (fd_u == -1) { 2211 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2212 _rtld_error("Cannot open \"%s\"", path); 2213 free(path); 2214 return (NULL); 2215 } 2216 } else { 2217 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2218 if (fd == -1) { 2219 _rtld_error("Cannot dup fd"); 2220 free(path); 2221 return (NULL); 2222 } 2223 } 2224 if (fstat(fd, &sb) == -1) { 2225 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2226 close(fd); 2227 free(path); 2228 return NULL; 2229 } 2230 TAILQ_FOREACH(obj, &obj_list, next) { 2231 if (obj->marker) 2232 continue; 2233 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2234 break; 2235 } 2236 if (obj != NULL && name != NULL) { 2237 object_add_name(obj, name); 2238 free(path); 2239 close(fd); 2240 return obj; 2241 } 2242 if (flags & RTLD_LO_NOLOAD) { 2243 free(path); 2244 close(fd); 2245 return (NULL); 2246 } 2247 2248 /* First use of this object, so we must map it in */ 2249 obj = do_load_object(fd, name, path, &sb, flags); 2250 if (obj == NULL) 2251 free(path); 2252 close(fd); 2253 2254 return obj; 2255} 2256 2257static Obj_Entry * 2258do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2259 int flags) 2260{ 2261 Obj_Entry *obj; 2262 struct statfs fs; 2263 2264 /* 2265 * but first, make sure that environment variables haven't been 2266 * used to circumvent the noexec flag on a filesystem. 2267 */ 2268 if (dangerous_ld_env) { 2269 if (fstatfs(fd, &fs) != 0) { 2270 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2271 return NULL; 2272 } 2273 if (fs.f_flags & MNT_NOEXEC) { 2274 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2275 return NULL; 2276 } 2277 } 2278 dbg("loading \"%s\"", printable_path(path)); 2279 obj = map_object(fd, printable_path(path), sbp); 2280 if (obj == NULL) 2281 return NULL; 2282 2283 /* 2284 * If DT_SONAME is present in the object, digest_dynamic2 already 2285 * added it to the object names. 2286 */ 2287 if (name != NULL) 2288 object_add_name(obj, name); 2289 obj->path = path; 2290 digest_dynamic(obj, 0); 2291 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2292 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2293 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2294 RTLD_LO_DLOPEN) { 2295 dbg("refusing to load non-loadable \"%s\"", obj->path); 2296 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2297 munmap(obj->mapbase, obj->mapsize); 2298 obj_free(obj); 2299 return (NULL); 2300 } 2301 2302 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2303 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2304 obj_count++; 2305 obj_loads++; 2306 linkmap_add(obj); /* for GDB & dlinfo() */ 2307 max_stack_flags |= obj->stack_flags; 2308 2309 dbg(" %p .. %p: %s", obj->mapbase, 2310 obj->mapbase + obj->mapsize - 1, obj->path); 2311 if (obj->textrel) 2312 dbg(" WARNING: %s has impure text", obj->path); 2313 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2314 obj->path); 2315 2316 return obj; 2317} 2318 2319static Obj_Entry * 2320obj_from_addr(const void *addr) 2321{ 2322 Obj_Entry *obj; 2323 2324 TAILQ_FOREACH(obj, &obj_list, next) { 2325 if (obj->marker) 2326 continue; 2327 if (addr < (void *) obj->mapbase) 2328 continue; 2329 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2330 return obj; 2331 } 2332 return NULL; 2333} 2334 2335static void 2336preinit_main(void) 2337{ 2338 Elf_Addr *preinit_addr; 2339 int index; 2340 2341 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2342 if (preinit_addr == NULL) 2343 return; 2344 2345 for (index = 0; index < obj_main->preinit_array_num; index++) { 2346 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2347 dbg("calling preinit function for %s at %p", obj_main->path, 2348 (void *)preinit_addr[index]); 2349 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2350 0, 0, obj_main->path); 2351 call_init_pointer(obj_main, preinit_addr[index]); 2352 } 2353 } 2354} 2355 2356/* 2357 * Call the finalization functions for each of the objects in "list" 2358 * belonging to the DAG of "root" and referenced once. If NULL "root" 2359 * is specified, every finalization function will be called regardless 2360 * of the reference count and the list elements won't be freed. All of 2361 * the objects are expected to have non-NULL fini functions. 2362 */ 2363static void 2364objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2365{ 2366 Objlist_Entry *elm; 2367 char *saved_msg; 2368 Elf_Addr *fini_addr; 2369 int index; 2370 2371 assert(root == NULL || root->refcount == 1); 2372 2373 /* 2374 * Preserve the current error message since a fini function might 2375 * call into the dynamic linker and overwrite it. 2376 */ 2377 saved_msg = errmsg_save(); 2378 do { 2379 STAILQ_FOREACH(elm, list, link) { 2380 if (root != NULL && (elm->obj->refcount != 1 || 2381 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2382 continue; 2383 /* Remove object from fini list to prevent recursive invocation. */ 2384 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2385 /* 2386 * XXX: If a dlopen() call references an object while the 2387 * fini function is in progress, we might end up trying to 2388 * unload the referenced object in dlclose() or the object 2389 * won't be unloaded although its fini function has been 2390 * called. 2391 */ 2392 lock_release(rtld_bind_lock, lockstate); 2393 2394 /* 2395 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2396 * When this happens, DT_FINI_ARRAY is processed first. 2397 */ 2398 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2399 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2400 for (index = elm->obj->fini_array_num - 1; index >= 0; 2401 index--) { 2402 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2403 dbg("calling fini function for %s at %p", 2404 elm->obj->path, (void *)fini_addr[index]); 2405 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2406 (void *)fini_addr[index], 0, 0, elm->obj->path); 2407 call_initfini_pointer(elm->obj, fini_addr[index]); 2408 } 2409 } 2410 } 2411 if (elm->obj->fini != (Elf_Addr)NULL) { 2412 dbg("calling fini function for %s at %p", elm->obj->path, 2413 (void *)elm->obj->fini); 2414 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2415 0, 0, elm->obj->path); 2416 call_initfini_pointer(elm->obj, elm->obj->fini); 2417 } 2418 wlock_acquire(rtld_bind_lock, lockstate); 2419 /* No need to free anything if process is going down. */ 2420 if (root != NULL) 2421 free(elm); 2422 /* 2423 * We must restart the list traversal after every fini call 2424 * because a dlclose() call from the fini function or from 2425 * another thread might have modified the reference counts. 2426 */ 2427 break; 2428 } 2429 } while (elm != NULL); 2430 errmsg_restore(saved_msg); 2431} 2432 2433/* 2434 * Call the initialization functions for each of the objects in 2435 * "list". All of the objects are expected to have non-NULL init 2436 * functions. 2437 */ 2438static void 2439objlist_call_init(Objlist *list, RtldLockState *lockstate) 2440{ 2441 Objlist_Entry *elm; 2442 Obj_Entry *obj; 2443 char *saved_msg; 2444 Elf_Addr *init_addr; 2445 int index; 2446 2447 /* 2448 * Clean init_scanned flag so that objects can be rechecked and 2449 * possibly initialized earlier if any of vectors called below 2450 * cause the change by using dlopen. 2451 */ 2452 TAILQ_FOREACH(obj, &obj_list, next) { 2453 if (obj->marker) 2454 continue; 2455 obj->init_scanned = false; 2456 } 2457 2458 /* 2459 * Preserve the current error message since an init function might 2460 * call into the dynamic linker and overwrite it. 2461 */ 2462 saved_msg = errmsg_save(); 2463 STAILQ_FOREACH(elm, list, link) { 2464 if (elm->obj->init_done) /* Initialized early. */ 2465 continue; 2466 /* 2467 * Race: other thread might try to use this object before current 2468 * one completes the initilization. Not much can be done here 2469 * without better locking. 2470 */ 2471 elm->obj->init_done = true; 2472 lock_release(rtld_bind_lock, lockstate); 2473 2474 /* 2475 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2476 * When this happens, DT_INIT is processed first. 2477 */ 2478 if (elm->obj->init != (Elf_Addr)NULL) { 2479 dbg("calling init function for %s at %p", elm->obj->path, 2480 (void *)elm->obj->init); 2481 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2482 0, 0, elm->obj->path); 2483 call_initfini_pointer(elm->obj, elm->obj->init); 2484 } 2485 init_addr = (Elf_Addr *)elm->obj->init_array; 2486 if (init_addr != NULL) { 2487 for (index = 0; index < elm->obj->init_array_num; index++) { 2488 if (init_addr[index] != 0 && init_addr[index] != 1) { 2489 dbg("calling init function for %s at %p", elm->obj->path, 2490 (void *)init_addr[index]); 2491 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2492 (void *)init_addr[index], 0, 0, elm->obj->path); 2493 call_init_pointer(elm->obj, init_addr[index]); 2494 } 2495 } 2496 } 2497 wlock_acquire(rtld_bind_lock, lockstate); 2498 } 2499 errmsg_restore(saved_msg); 2500} 2501 2502static void 2503objlist_clear(Objlist *list) 2504{ 2505 Objlist_Entry *elm; 2506 2507 while (!STAILQ_EMPTY(list)) { 2508 elm = STAILQ_FIRST(list); 2509 STAILQ_REMOVE_HEAD(list, link); 2510 free(elm); 2511 } 2512} 2513 2514static Objlist_Entry * 2515objlist_find(Objlist *list, const Obj_Entry *obj) 2516{ 2517 Objlist_Entry *elm; 2518 2519 STAILQ_FOREACH(elm, list, link) 2520 if (elm->obj == obj) 2521 return elm; 2522 return NULL; 2523} 2524 2525static void 2526objlist_init(Objlist *list) 2527{ 2528 STAILQ_INIT(list); 2529} 2530 2531static void 2532objlist_push_head(Objlist *list, Obj_Entry *obj) 2533{ 2534 Objlist_Entry *elm; 2535 2536 elm = NEW(Objlist_Entry); 2537 elm->obj = obj; 2538 STAILQ_INSERT_HEAD(list, elm, link); 2539} 2540 2541static void 2542objlist_push_tail(Objlist *list, Obj_Entry *obj) 2543{ 2544 Objlist_Entry *elm; 2545 2546 elm = NEW(Objlist_Entry); 2547 elm->obj = obj; 2548 STAILQ_INSERT_TAIL(list, elm, link); 2549} 2550 2551static void 2552objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2553{ 2554 Objlist_Entry *elm, *listelm; 2555 2556 STAILQ_FOREACH(listelm, list, link) { 2557 if (listelm->obj == listobj) 2558 break; 2559 } 2560 elm = NEW(Objlist_Entry); 2561 elm->obj = obj; 2562 if (listelm != NULL) 2563 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2564 else 2565 STAILQ_INSERT_TAIL(list, elm, link); 2566} 2567 2568static void 2569objlist_remove(Objlist *list, Obj_Entry *obj) 2570{ 2571 Objlist_Entry *elm; 2572 2573 if ((elm = objlist_find(list, obj)) != NULL) { 2574 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2575 free(elm); 2576 } 2577} 2578 2579/* 2580 * Relocate dag rooted in the specified object. 2581 * Returns 0 on success, or -1 on failure. 2582 */ 2583 2584static int 2585relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2586 int flags, RtldLockState *lockstate) 2587{ 2588 Objlist_Entry *elm; 2589 int error; 2590 2591 error = 0; 2592 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2593 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2594 lockstate); 2595 if (error == -1) 2596 break; 2597 } 2598 return (error); 2599} 2600 2601/* 2602 * Prepare for, or clean after, relocating an object marked with 2603 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2604 * segments are remapped read-write. After relocations are done, the 2605 * segment's permissions are returned back to the modes specified in 2606 * the phdrs. If any relocation happened, or always for wired 2607 * program, COW is triggered. 2608 */ 2609static int 2610reloc_textrel_prot(Obj_Entry *obj, bool before) 2611{ 2612 const Elf_Phdr *ph; 2613 void *base; 2614 size_t l, sz; 2615 int prot; 2616 2617 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2618 l--, ph++) { 2619 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2620 continue; 2621 base = obj->relocbase + trunc_page(ph->p_vaddr); 2622 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2623 trunc_page(ph->p_vaddr); 2624 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2625 if (mprotect(base, sz, prot) == -1) { 2626 _rtld_error("%s: Cannot write-%sable text segment: %s", 2627 obj->path, before ? "en" : "dis", 2628 rtld_strerror(errno)); 2629 return (-1); 2630 } 2631 } 2632 return (0); 2633} 2634 2635/* 2636 * Relocate single object. 2637 * Returns 0 on success, or -1 on failure. 2638 */ 2639static int 2640relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2641 int flags, RtldLockState *lockstate) 2642{ 2643 2644 if (obj->relocated) 2645 return (0); 2646 obj->relocated = true; 2647 if (obj != rtldobj) 2648 dbg("relocating \"%s\"", obj->path); 2649 2650 if (obj->symtab == NULL || obj->strtab == NULL || 2651 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2652 _rtld_error("%s: Shared object has no run-time symbol table", 2653 obj->path); 2654 return (-1); 2655 } 2656 2657 /* There are relocations to the write-protected text segment. */ 2658 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2659 return (-1); 2660 2661 /* Process the non-PLT non-IFUNC relocations. */ 2662 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2663 return (-1); 2664 2665 /* Re-protected the text segment. */ 2666 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2667 return (-1); 2668 2669 /* Set the special PLT or GOT entries. */ 2670 init_pltgot(obj); 2671 2672 /* Process the PLT relocations. */ 2673 if (reloc_plt(obj) == -1) 2674 return (-1); 2675 /* Relocate the jump slots if we are doing immediate binding. */ 2676 if (obj->bind_now || bind_now) 2677 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2678 return (-1); 2679 2680 /* 2681 * Process the non-PLT IFUNC relocations. The relocations are 2682 * processed in two phases, because IFUNC resolvers may 2683 * reference other symbols, which must be readily processed 2684 * before resolvers are called. 2685 */ 2686 if (obj->non_plt_gnu_ifunc && 2687 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2688 return (-1); 2689 2690 if (obj->relro_size > 0) { 2691 if (mprotect(obj->relro_page, obj->relro_size, 2692 PROT_READ) == -1) { 2693 _rtld_error("%s: Cannot enforce relro protection: %s", 2694 obj->path, rtld_strerror(errno)); 2695 return (-1); 2696 } 2697 } 2698 2699 /* 2700 * Set up the magic number and version in the Obj_Entry. These 2701 * were checked in the crt1.o from the original ElfKit, so we 2702 * set them for backward compatibility. 2703 */ 2704 obj->magic = RTLD_MAGIC; 2705 obj->version = RTLD_VERSION; 2706 2707 return (0); 2708} 2709 2710/* 2711 * Relocate newly-loaded shared objects. The argument is a pointer to 2712 * the Obj_Entry for the first such object. All objects from the first 2713 * to the end of the list of objects are relocated. Returns 0 on success, 2714 * or -1 on failure. 2715 */ 2716static int 2717relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2718 int flags, RtldLockState *lockstate) 2719{ 2720 Obj_Entry *obj; 2721 int error; 2722 2723 error = 0; 2724 obj = first; 2725 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2726 if (obj->marker) 2727 continue; 2728 error = relocate_object(obj, bind_now, rtldobj, flags, 2729 lockstate); 2730 if (error == -1) 2731 break; 2732 } 2733 return (error); 2734} 2735 2736/* 2737 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2738 * referencing STT_GNU_IFUNC symbols is postponed till the other 2739 * relocations are done. The indirect functions specified as 2740 * ifunc are allowed to call other symbols, so we need to have 2741 * objects relocated before asking for resolution from indirects. 2742 * 2743 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2744 * instead of the usual lazy handling of PLT slots. It is 2745 * consistent with how GNU does it. 2746 */ 2747static int 2748resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2749 RtldLockState *lockstate) 2750{ 2751 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2752 return (-1); 2753 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2754 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2755 return (-1); 2756 return (0); 2757} 2758 2759static int 2760resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2761 RtldLockState *lockstate) 2762{ 2763 Obj_Entry *obj; 2764 2765 obj = first; 2766 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 2767 if (obj->marker) 2768 continue; 2769 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2770 return (-1); 2771 } 2772 return (0); 2773} 2774 2775static int 2776initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2777 RtldLockState *lockstate) 2778{ 2779 Objlist_Entry *elm; 2780 2781 STAILQ_FOREACH(elm, list, link) { 2782 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2783 lockstate) == -1) 2784 return (-1); 2785 } 2786 return (0); 2787} 2788 2789/* 2790 * Cleanup procedure. It will be called (by the atexit mechanism) just 2791 * before the process exits. 2792 */ 2793static void 2794rtld_exit(void) 2795{ 2796 RtldLockState lockstate; 2797 2798 wlock_acquire(rtld_bind_lock, &lockstate); 2799 dbg("rtld_exit()"); 2800 objlist_call_fini(&list_fini, NULL, &lockstate); 2801 /* No need to remove the items from the list, since we are exiting. */ 2802 if (!libmap_disable) 2803 lm_fini(); 2804 lock_release(rtld_bind_lock, &lockstate); 2805} 2806 2807/* 2808 * Iterate over a search path, translate each element, and invoke the 2809 * callback on the result. 2810 */ 2811static void * 2812path_enumerate(const char *path, path_enum_proc callback, void *arg) 2813{ 2814 const char *trans; 2815 if (path == NULL) 2816 return (NULL); 2817 2818 path += strspn(path, ":;"); 2819 while (*path != '\0') { 2820 size_t len; 2821 char *res; 2822 2823 len = strcspn(path, ":;"); 2824 trans = lm_findn(NULL, path, len); 2825 if (trans) 2826 res = callback(trans, strlen(trans), arg); 2827 else 2828 res = callback(path, len, arg); 2829 2830 if (res != NULL) 2831 return (res); 2832 2833 path += len; 2834 path += strspn(path, ":;"); 2835 } 2836 2837 return (NULL); 2838} 2839 2840struct try_library_args { 2841 const char *name; 2842 size_t namelen; 2843 char *buffer; 2844 size_t buflen; 2845}; 2846 2847static void * 2848try_library_path(const char *dir, size_t dirlen, void *param) 2849{ 2850 struct try_library_args *arg; 2851 2852 arg = param; 2853 if (*dir == '/' || trust) { 2854 char *pathname; 2855 2856 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2857 return (NULL); 2858 2859 pathname = arg->buffer; 2860 strncpy(pathname, dir, dirlen); 2861 pathname[dirlen] = '/'; 2862 strcpy(pathname + dirlen + 1, arg->name); 2863 2864 dbg(" Trying \"%s\"", pathname); 2865 if (access(pathname, F_OK) == 0) { /* We found it */ 2866 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2867 strcpy(pathname, arg->buffer); 2868 return (pathname); 2869 } 2870 } 2871 return (NULL); 2872} 2873 2874static char * 2875search_library_path(const char *name, const char *path) 2876{ 2877 char *p; 2878 struct try_library_args arg; 2879 2880 if (path == NULL) 2881 return NULL; 2882 2883 arg.name = name; 2884 arg.namelen = strlen(name); 2885 arg.buffer = xmalloc(PATH_MAX); 2886 arg.buflen = PATH_MAX; 2887 2888 p = path_enumerate(path, try_library_path, &arg); 2889 2890 free(arg.buffer); 2891 2892 return (p); 2893} 2894 2895int 2896dlclose(void *handle) 2897{ 2898 Obj_Entry *root; 2899 RtldLockState lockstate; 2900 2901 wlock_acquire(rtld_bind_lock, &lockstate); 2902 root = dlcheck(handle); 2903 if (root == NULL) { 2904 lock_release(rtld_bind_lock, &lockstate); 2905 return -1; 2906 } 2907 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2908 root->path); 2909 2910 /* Unreference the object and its dependencies. */ 2911 root->dl_refcount--; 2912 2913 if (root->refcount == 1) { 2914 /* 2915 * The object will be no longer referenced, so we must unload it. 2916 * First, call the fini functions. 2917 */ 2918 objlist_call_fini(&list_fini, root, &lockstate); 2919 2920 unref_dag(root); 2921 2922 /* Finish cleaning up the newly-unreferenced objects. */ 2923 GDB_STATE(RT_DELETE,&root->linkmap); 2924 unload_object(root); 2925 GDB_STATE(RT_CONSISTENT,NULL); 2926 } else 2927 unref_dag(root); 2928 2929 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2930 lock_release(rtld_bind_lock, &lockstate); 2931 return 0; 2932} 2933 2934char * 2935dlerror(void) 2936{ 2937 char *msg = error_message; 2938 error_message = NULL; 2939 return msg; 2940} 2941 2942/* 2943 * This function is deprecated and has no effect. 2944 */ 2945void 2946dllockinit(void *context, 2947 void *(*lock_create)(void *context), 2948 void (*rlock_acquire)(void *lock), 2949 void (*wlock_acquire)(void *lock), 2950 void (*lock_release)(void *lock), 2951 void (*lock_destroy)(void *lock), 2952 void (*context_destroy)(void *context)) 2953{ 2954 static void *cur_context; 2955 static void (*cur_context_destroy)(void *); 2956 2957 /* Just destroy the context from the previous call, if necessary. */ 2958 if (cur_context_destroy != NULL) 2959 cur_context_destroy(cur_context); 2960 cur_context = context; 2961 cur_context_destroy = context_destroy; 2962} 2963 2964void * 2965dlopen(const char *name, int mode) 2966{ 2967 2968 return (rtld_dlopen(name, -1, mode)); 2969} 2970 2971void * 2972fdlopen(int fd, int mode) 2973{ 2974 2975 return (rtld_dlopen(NULL, fd, mode)); 2976} 2977 2978static void * 2979rtld_dlopen(const char *name, int fd, int mode) 2980{ 2981 RtldLockState lockstate; 2982 int lo_flags; 2983 2984 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2985 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2986 if (ld_tracing != NULL) { 2987 rlock_acquire(rtld_bind_lock, &lockstate); 2988 if (sigsetjmp(lockstate.env, 0) != 0) 2989 lock_upgrade(rtld_bind_lock, &lockstate); 2990 environ = (char **)*get_program_var_addr("environ", &lockstate); 2991 lock_release(rtld_bind_lock, &lockstate); 2992 } 2993 lo_flags = RTLD_LO_DLOPEN; 2994 if (mode & RTLD_NODELETE) 2995 lo_flags |= RTLD_LO_NODELETE; 2996 if (mode & RTLD_NOLOAD) 2997 lo_flags |= RTLD_LO_NOLOAD; 2998 if (ld_tracing != NULL) 2999 lo_flags |= RTLD_LO_TRACE; 3000 3001 return (dlopen_object(name, fd, obj_main, lo_flags, 3002 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3003} 3004 3005static void 3006dlopen_cleanup(Obj_Entry *obj) 3007{ 3008 3009 obj->dl_refcount--; 3010 unref_dag(obj); 3011 if (obj->refcount == 0) 3012 unload_object(obj); 3013} 3014 3015static Obj_Entry * 3016dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3017 int mode, RtldLockState *lockstate) 3018{ 3019 Obj_Entry *old_obj_tail; 3020 Obj_Entry *obj; 3021 Objlist initlist; 3022 RtldLockState mlockstate; 3023 int result; 3024 3025 objlist_init(&initlist); 3026 3027 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3028 wlock_acquire(rtld_bind_lock, &mlockstate); 3029 lockstate = &mlockstate; 3030 } 3031 GDB_STATE(RT_ADD,NULL); 3032 3033 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3034 obj = NULL; 3035 if (name == NULL && fd == -1) { 3036 obj = obj_main; 3037 obj->refcount++; 3038 } else { 3039 obj = load_object(name, fd, refobj, lo_flags); 3040 } 3041 3042 if (obj) { 3043 obj->dl_refcount++; 3044 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3045 objlist_push_tail(&list_global, obj); 3046 if (globallist_next(old_obj_tail) != NULL) { 3047 /* We loaded something new. */ 3048 assert(globallist_next(old_obj_tail) == obj); 3049 result = load_needed_objects(obj, 3050 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3051 init_dag(obj); 3052 ref_dag(obj); 3053 if (result != -1) 3054 result = rtld_verify_versions(&obj->dagmembers); 3055 if (result != -1 && ld_tracing) 3056 goto trace; 3057 if (result == -1 || relocate_object_dag(obj, 3058 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3059 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3060 lockstate) == -1) { 3061 dlopen_cleanup(obj); 3062 obj = NULL; 3063 } else if (lo_flags & RTLD_LO_EARLY) { 3064 /* 3065 * Do not call the init functions for early loaded 3066 * filtees. The image is still not initialized enough 3067 * for them to work. 3068 * 3069 * Our object is found by the global object list and 3070 * will be ordered among all init calls done right 3071 * before transferring control to main. 3072 */ 3073 } else { 3074 /* Make list of init functions to call. */ 3075 initlist_add_objects(obj, obj, &initlist); 3076 } 3077 /* 3078 * Process all no_delete or global objects here, given 3079 * them own DAGs to prevent their dependencies from being 3080 * unloaded. This has to be done after we have loaded all 3081 * of the dependencies, so that we do not miss any. 3082 */ 3083 if (obj != NULL) 3084 process_z(obj); 3085 } else { 3086 /* 3087 * Bump the reference counts for objects on this DAG. If 3088 * this is the first dlopen() call for the object that was 3089 * already loaded as a dependency, initialize the dag 3090 * starting at it. 3091 */ 3092 init_dag(obj); 3093 ref_dag(obj); 3094 3095 if ((lo_flags & RTLD_LO_TRACE) != 0) 3096 goto trace; 3097 } 3098 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3099 obj->z_nodelete) && !obj->ref_nodel) { 3100 dbg("obj %s nodelete", obj->path); 3101 ref_dag(obj); 3102 obj->z_nodelete = obj->ref_nodel = true; 3103 } 3104 } 3105 3106 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3107 name); 3108 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3109 3110 if (!(lo_flags & RTLD_LO_EARLY)) { 3111 map_stacks_exec(lockstate); 3112 } 3113 3114 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3115 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3116 lockstate) == -1) { 3117 objlist_clear(&initlist); 3118 dlopen_cleanup(obj); 3119 if (lockstate == &mlockstate) 3120 lock_release(rtld_bind_lock, lockstate); 3121 return (NULL); 3122 } 3123 3124 if (!(lo_flags & RTLD_LO_EARLY)) { 3125 /* Call the init functions. */ 3126 objlist_call_init(&initlist, lockstate); 3127 } 3128 objlist_clear(&initlist); 3129 if (lockstate == &mlockstate) 3130 lock_release(rtld_bind_lock, lockstate); 3131 return obj; 3132trace: 3133 trace_loaded_objects(obj); 3134 if (lockstate == &mlockstate) 3135 lock_release(rtld_bind_lock, lockstate); 3136 exit(0); 3137} 3138 3139static void * 3140do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3141 int flags) 3142{ 3143 DoneList donelist; 3144 const Obj_Entry *obj, *defobj; 3145 const Elf_Sym *def; 3146 SymLook req; 3147 RtldLockState lockstate; 3148#ifndef __ia64__ 3149 tls_index ti; 3150#endif 3151 void *sym; 3152 int res; 3153 3154 def = NULL; 3155 defobj = NULL; 3156 symlook_init(&req, name); 3157 req.ventry = ve; 3158 req.flags = flags | SYMLOOK_IN_PLT; 3159 req.lockstate = &lockstate; 3160 3161 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3162 rlock_acquire(rtld_bind_lock, &lockstate); 3163 if (sigsetjmp(lockstate.env, 0) != 0) 3164 lock_upgrade(rtld_bind_lock, &lockstate); 3165 if (handle == NULL || handle == RTLD_NEXT || 3166 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3167 3168 if ((obj = obj_from_addr(retaddr)) == NULL) { 3169 _rtld_error("Cannot determine caller's shared object"); 3170 lock_release(rtld_bind_lock, &lockstate); 3171 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3172 return NULL; 3173 } 3174 if (handle == NULL) { /* Just the caller's shared object. */ 3175 res = symlook_obj(&req, obj); 3176 if (res == 0) { 3177 def = req.sym_out; 3178 defobj = req.defobj_out; 3179 } 3180 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3181 handle == RTLD_SELF) { /* ... caller included */ 3182 if (handle == RTLD_NEXT) 3183 obj = globallist_next(obj); 3184 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3185 if (obj->marker) 3186 continue; 3187 res = symlook_obj(&req, obj); 3188 if (res == 0) { 3189 if (def == NULL || 3190 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3191 def = req.sym_out; 3192 defobj = req.defobj_out; 3193 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3194 break; 3195 } 3196 } 3197 } 3198 /* 3199 * Search the dynamic linker itself, and possibly resolve the 3200 * symbol from there. This is how the application links to 3201 * dynamic linker services such as dlopen. 3202 */ 3203 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3204 res = symlook_obj(&req, &obj_rtld); 3205 if (res == 0) { 3206 def = req.sym_out; 3207 defobj = req.defobj_out; 3208 } 3209 } 3210 } else { 3211 assert(handle == RTLD_DEFAULT); 3212 res = symlook_default(&req, obj); 3213 if (res == 0) { 3214 defobj = req.defobj_out; 3215 def = req.sym_out; 3216 } 3217 } 3218 } else { 3219 if ((obj = dlcheck(handle)) == NULL) { 3220 lock_release(rtld_bind_lock, &lockstate); 3221 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3222 return NULL; 3223 } 3224 3225 donelist_init(&donelist); 3226 if (obj->mainprog) { 3227 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3228 res = symlook_global(&req, &donelist); 3229 if (res == 0) { 3230 def = req.sym_out; 3231 defobj = req.defobj_out; 3232 } 3233 /* 3234 * Search the dynamic linker itself, and possibly resolve the 3235 * symbol from there. This is how the application links to 3236 * dynamic linker services such as dlopen. 3237 */ 3238 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3239 res = symlook_obj(&req, &obj_rtld); 3240 if (res == 0) { 3241 def = req.sym_out; 3242 defobj = req.defobj_out; 3243 } 3244 } 3245 } 3246 else { 3247 /* Search the whole DAG rooted at the given object. */ 3248 res = symlook_list(&req, &obj->dagmembers, &donelist); 3249 if (res == 0) { 3250 def = req.sym_out; 3251 defobj = req.defobj_out; 3252 } 3253 } 3254 } 3255 3256 if (def != NULL) { 3257 lock_release(rtld_bind_lock, &lockstate); 3258 3259 /* 3260 * The value required by the caller is derived from the value 3261 * of the symbol. For the ia64 architecture, we need to 3262 * construct a function descriptor which the caller can use to 3263 * call the function with the right 'gp' value. For other 3264 * architectures and for non-functions, the value is simply 3265 * the relocated value of the symbol. 3266 */ 3267 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3268 sym = make_function_pointer(def, defobj); 3269 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3270 sym = rtld_resolve_ifunc(defobj, def); 3271 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3272#ifdef __ia64__ 3273 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3274#else 3275 ti.ti_module = defobj->tlsindex; 3276 ti.ti_offset = def->st_value; 3277 sym = __tls_get_addr(&ti); 3278#endif 3279 } else 3280 sym = defobj->relocbase + def->st_value; 3281 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3282 return (sym); 3283 } 3284 3285 _rtld_error("Undefined symbol \"%s\"", name); 3286 lock_release(rtld_bind_lock, &lockstate); 3287 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3288 return NULL; 3289} 3290 3291void * 3292dlsym(void *handle, const char *name) 3293{ 3294 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3295 SYMLOOK_DLSYM); 3296} 3297 3298dlfunc_t 3299dlfunc(void *handle, const char *name) 3300{ 3301 union { 3302 void *d; 3303 dlfunc_t f; 3304 } rv; 3305 3306 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3307 SYMLOOK_DLSYM); 3308 return (rv.f); 3309} 3310 3311void * 3312dlvsym(void *handle, const char *name, const char *version) 3313{ 3314 Ver_Entry ventry; 3315 3316 ventry.name = version; 3317 ventry.file = NULL; 3318 ventry.hash = elf_hash(version); 3319 ventry.flags= 0; 3320 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3321 SYMLOOK_DLSYM); 3322} 3323 3324int 3325_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3326{ 3327 const Obj_Entry *obj; 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 rtld_fill_dl_phdr_info(obj, phdr_info); 3338 lock_release(rtld_bind_lock, &lockstate); 3339 return (1); 3340} 3341 3342int 3343dladdr(const void *addr, Dl_info *info) 3344{ 3345 const Obj_Entry *obj; 3346 const Elf_Sym *def; 3347 void *symbol_addr; 3348 unsigned long symoffset; 3349 RtldLockState lockstate; 3350 3351 rlock_acquire(rtld_bind_lock, &lockstate); 3352 obj = obj_from_addr(addr); 3353 if (obj == NULL) { 3354 _rtld_error("No shared object contains address"); 3355 lock_release(rtld_bind_lock, &lockstate); 3356 return 0; 3357 } 3358 info->dli_fname = obj->path; 3359 info->dli_fbase = obj->mapbase; 3360 info->dli_saddr = (void *)0; 3361 info->dli_sname = NULL; 3362 3363 /* 3364 * Walk the symbol list looking for the symbol whose address is 3365 * closest to the address sent in. 3366 */ 3367 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3368 def = obj->symtab + symoffset; 3369 3370 /* 3371 * For skip the symbol if st_shndx is either SHN_UNDEF or 3372 * SHN_COMMON. 3373 */ 3374 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3375 continue; 3376 3377 /* 3378 * If the symbol is greater than the specified address, or if it 3379 * is further away from addr than the current nearest symbol, 3380 * then reject it. 3381 */ 3382 symbol_addr = obj->relocbase + def->st_value; 3383 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3384 continue; 3385 3386 /* Update our idea of the nearest symbol. */ 3387 info->dli_sname = obj->strtab + def->st_name; 3388 info->dli_saddr = symbol_addr; 3389 3390 /* Exact match? */ 3391 if (info->dli_saddr == addr) 3392 break; 3393 } 3394 lock_release(rtld_bind_lock, &lockstate); 3395 return 1; 3396} 3397 3398int 3399dlinfo(void *handle, int request, void *p) 3400{ 3401 const Obj_Entry *obj; 3402 RtldLockState lockstate; 3403 int error; 3404 3405 rlock_acquire(rtld_bind_lock, &lockstate); 3406 3407 if (handle == NULL || handle == RTLD_SELF) { 3408 void *retaddr; 3409 3410 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3411 if ((obj = obj_from_addr(retaddr)) == NULL) 3412 _rtld_error("Cannot determine caller's shared object"); 3413 } else 3414 obj = dlcheck(handle); 3415 3416 if (obj == NULL) { 3417 lock_release(rtld_bind_lock, &lockstate); 3418 return (-1); 3419 } 3420 3421 error = 0; 3422 switch (request) { 3423 case RTLD_DI_LINKMAP: 3424 *((struct link_map const **)p) = &obj->linkmap; 3425 break; 3426 case RTLD_DI_ORIGIN: 3427 error = rtld_dirname(obj->path, p); 3428 break; 3429 3430 case RTLD_DI_SERINFOSIZE: 3431 case RTLD_DI_SERINFO: 3432 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3433 break; 3434 3435 default: 3436 _rtld_error("Invalid request %d passed to dlinfo()", request); 3437 error = -1; 3438 } 3439 3440 lock_release(rtld_bind_lock, &lockstate); 3441 3442 return (error); 3443} 3444 3445static void 3446rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3447{ 3448 3449 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3450 phdr_info->dlpi_name = obj->path; 3451 phdr_info->dlpi_phdr = obj->phdr; 3452 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3453 phdr_info->dlpi_tls_modid = obj->tlsindex; 3454 phdr_info->dlpi_tls_data = obj->tlsinit; 3455 phdr_info->dlpi_adds = obj_loads; 3456 phdr_info->dlpi_subs = obj_loads - obj_count; 3457} 3458 3459int 3460dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3461{ 3462 struct dl_phdr_info phdr_info; 3463 Obj_Entry *obj, marker; 3464 RtldLockState bind_lockstate, phdr_lockstate; 3465 int error; 3466 3467 bzero(&marker, sizeof(marker)); 3468 marker.marker = true; 3469 error = 0; 3470 3471 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3472 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3473 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3474 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3475 rtld_fill_dl_phdr_info(obj, &phdr_info); 3476 lock_release(rtld_bind_lock, &bind_lockstate); 3477 3478 error = callback(&phdr_info, sizeof phdr_info, param); 3479 3480 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3481 obj = globallist_next(&marker); 3482 TAILQ_REMOVE(&obj_list, &marker, next); 3483 if (error != 0) { 3484 lock_release(rtld_bind_lock, &bind_lockstate); 3485 lock_release(rtld_phdr_lock, &phdr_lockstate); 3486 return (error); 3487 } 3488 } 3489 3490 if (error == 0) { 3491 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3492 lock_release(rtld_bind_lock, &bind_lockstate); 3493 error = callback(&phdr_info, sizeof(phdr_info), param); 3494 } 3495 lock_release(rtld_phdr_lock, &phdr_lockstate); 3496 return (error); 3497} 3498 3499static void * 3500fill_search_info(const char *dir, size_t dirlen, void *param) 3501{ 3502 struct fill_search_info_args *arg; 3503 3504 arg = param; 3505 3506 if (arg->request == RTLD_DI_SERINFOSIZE) { 3507 arg->serinfo->dls_cnt ++; 3508 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3509 } else { 3510 struct dl_serpath *s_entry; 3511 3512 s_entry = arg->serpath; 3513 s_entry->dls_name = arg->strspace; 3514 s_entry->dls_flags = arg->flags; 3515 3516 strncpy(arg->strspace, dir, dirlen); 3517 arg->strspace[dirlen] = '\0'; 3518 3519 arg->strspace += dirlen + 1; 3520 arg->serpath++; 3521 } 3522 3523 return (NULL); 3524} 3525 3526static int 3527do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3528{ 3529 struct dl_serinfo _info; 3530 struct fill_search_info_args args; 3531 3532 args.request = RTLD_DI_SERINFOSIZE; 3533 args.serinfo = &_info; 3534 3535 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3536 _info.dls_cnt = 0; 3537 3538 path_enumerate(obj->rpath, fill_search_info, &args); 3539 path_enumerate(ld_library_path, fill_search_info, &args); 3540 path_enumerate(obj->runpath, fill_search_info, &args); 3541 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3542 if (!obj->z_nodeflib) 3543 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3544 3545 3546 if (request == RTLD_DI_SERINFOSIZE) { 3547 info->dls_size = _info.dls_size; 3548 info->dls_cnt = _info.dls_cnt; 3549 return (0); 3550 } 3551 3552 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3553 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3554 return (-1); 3555 } 3556 3557 args.request = RTLD_DI_SERINFO; 3558 args.serinfo = info; 3559 args.serpath = &info->dls_serpath[0]; 3560 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3561 3562 args.flags = LA_SER_RUNPATH; 3563 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3564 return (-1); 3565 3566 args.flags = LA_SER_LIBPATH; 3567 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3568 return (-1); 3569 3570 args.flags = LA_SER_RUNPATH; 3571 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3572 return (-1); 3573 3574 args.flags = LA_SER_CONFIG; 3575 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3576 != NULL) 3577 return (-1); 3578 3579 args.flags = LA_SER_DEFAULT; 3580 if (!obj->z_nodeflib && 3581 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3582 return (-1); 3583 return (0); 3584} 3585 3586static int 3587rtld_dirname(const char *path, char *bname) 3588{ 3589 const char *endp; 3590 3591 /* Empty or NULL string gets treated as "." */ 3592 if (path == NULL || *path == '\0') { 3593 bname[0] = '.'; 3594 bname[1] = '\0'; 3595 return (0); 3596 } 3597 3598 /* Strip trailing slashes */ 3599 endp = path + strlen(path) - 1; 3600 while (endp > path && *endp == '/') 3601 endp--; 3602 3603 /* Find the start of the dir */ 3604 while (endp > path && *endp != '/') 3605 endp--; 3606 3607 /* Either the dir is "/" or there are no slashes */ 3608 if (endp == path) { 3609 bname[0] = *endp == '/' ? '/' : '.'; 3610 bname[1] = '\0'; 3611 return (0); 3612 } else { 3613 do { 3614 endp--; 3615 } while (endp > path && *endp == '/'); 3616 } 3617 3618 if (endp - path + 2 > PATH_MAX) 3619 { 3620 _rtld_error("Filename is too long: %s", path); 3621 return(-1); 3622 } 3623 3624 strncpy(bname, path, endp - path + 1); 3625 bname[endp - path + 1] = '\0'; 3626 return (0); 3627} 3628 3629static int 3630rtld_dirname_abs(const char *path, char *base) 3631{ 3632 char *last; 3633 3634 if (realpath(path, base) == NULL) 3635 return (-1); 3636 dbg("%s -> %s", path, base); 3637 last = strrchr(base, '/'); 3638 if (last == NULL) 3639 return (-1); 3640 if (last != base) 3641 *last = '\0'; 3642 return (0); 3643} 3644 3645static void 3646linkmap_add(Obj_Entry *obj) 3647{ 3648 struct link_map *l = &obj->linkmap; 3649 struct link_map *prev; 3650 3651 obj->linkmap.l_name = obj->path; 3652 obj->linkmap.l_addr = obj->mapbase; 3653 obj->linkmap.l_ld = obj->dynamic; 3654#ifdef __mips__ 3655 /* GDB needs load offset on MIPS to use the symbols */ 3656 obj->linkmap.l_offs = obj->relocbase; 3657#endif 3658 3659 if (r_debug.r_map == NULL) { 3660 r_debug.r_map = l; 3661 return; 3662 } 3663 3664 /* 3665 * Scan to the end of the list, but not past the entry for the 3666 * dynamic linker, which we want to keep at the very end. 3667 */ 3668 for (prev = r_debug.r_map; 3669 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3670 prev = prev->l_next) 3671 ; 3672 3673 /* Link in the new entry. */ 3674 l->l_prev = prev; 3675 l->l_next = prev->l_next; 3676 if (l->l_next != NULL) 3677 l->l_next->l_prev = l; 3678 prev->l_next = l; 3679} 3680 3681static void 3682linkmap_delete(Obj_Entry *obj) 3683{ 3684 struct link_map *l = &obj->linkmap; 3685 3686 if (l->l_prev == NULL) { 3687 if ((r_debug.r_map = l->l_next) != NULL) 3688 l->l_next->l_prev = NULL; 3689 return; 3690 } 3691 3692 if ((l->l_prev->l_next = l->l_next) != NULL) 3693 l->l_next->l_prev = l->l_prev; 3694} 3695 3696/* 3697 * Function for the debugger to set a breakpoint on to gain control. 3698 * 3699 * The two parameters allow the debugger to easily find and determine 3700 * what the runtime loader is doing and to whom it is doing it. 3701 * 3702 * When the loadhook trap is hit (r_debug_state, set at program 3703 * initialization), the arguments can be found on the stack: 3704 * 3705 * +8 struct link_map *m 3706 * +4 struct r_debug *rd 3707 * +0 RetAddr 3708 */ 3709void 3710r_debug_state(struct r_debug* rd, struct link_map *m) 3711{ 3712 /* 3713 * The following is a hack to force the compiler to emit calls to 3714 * this function, even when optimizing. If the function is empty, 3715 * the compiler is not obliged to emit any code for calls to it, 3716 * even when marked __noinline. However, gdb depends on those 3717 * calls being made. 3718 */ 3719 __compiler_membar(); 3720} 3721 3722/* 3723 * A function called after init routines have completed. This can be used to 3724 * break before a program's entry routine is called, and can be used when 3725 * main is not available in the symbol table. 3726 */ 3727void 3728_r_debug_postinit(struct link_map *m) 3729{ 3730 3731 /* See r_debug_state(). */ 3732 __compiler_membar(); 3733} 3734 3735/* 3736 * Get address of the pointer variable in the main program. 3737 * Prefer non-weak symbol over the weak one. 3738 */ 3739static const void ** 3740get_program_var_addr(const char *name, RtldLockState *lockstate) 3741{ 3742 SymLook req; 3743 DoneList donelist; 3744 3745 symlook_init(&req, name); 3746 req.lockstate = lockstate; 3747 donelist_init(&donelist); 3748 if (symlook_global(&req, &donelist) != 0) 3749 return (NULL); 3750 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3751 return ((const void **)make_function_pointer(req.sym_out, 3752 req.defobj_out)); 3753 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3754 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3755 else 3756 return ((const void **)(req.defobj_out->relocbase + 3757 req.sym_out->st_value)); 3758} 3759 3760/* 3761 * Set a pointer variable in the main program to the given value. This 3762 * is used to set key variables such as "environ" before any of the 3763 * init functions are called. 3764 */ 3765static void 3766set_program_var(const char *name, const void *value) 3767{ 3768 const void **addr; 3769 3770 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3771 dbg("\"%s\": *%p <-- %p", name, addr, value); 3772 *addr = value; 3773 } 3774} 3775 3776/* 3777 * Search the global objects, including dependencies and main object, 3778 * for the given symbol. 3779 */ 3780static int 3781symlook_global(SymLook *req, DoneList *donelist) 3782{ 3783 SymLook req1; 3784 const Objlist_Entry *elm; 3785 int res; 3786 3787 symlook_init_from_req(&req1, req); 3788 3789 /* Search all objects loaded at program start up. */ 3790 if (req->defobj_out == NULL || 3791 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3792 res = symlook_list(&req1, &list_main, donelist); 3793 if (res == 0 && (req->defobj_out == NULL || 3794 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3795 req->sym_out = req1.sym_out; 3796 req->defobj_out = req1.defobj_out; 3797 assert(req->defobj_out != NULL); 3798 } 3799 } 3800 3801 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3802 STAILQ_FOREACH(elm, &list_global, link) { 3803 if (req->defobj_out != NULL && 3804 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3805 break; 3806 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3807 if (res == 0 && (req->defobj_out == NULL || 3808 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3809 req->sym_out = req1.sym_out; 3810 req->defobj_out = req1.defobj_out; 3811 assert(req->defobj_out != NULL); 3812 } 3813 } 3814 3815 return (req->sym_out != NULL ? 0 : ESRCH); 3816} 3817 3818/* 3819 * Given a symbol name in a referencing object, find the corresponding 3820 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3821 * no definition was found. Returns a pointer to the Obj_Entry of the 3822 * defining object via the reference parameter DEFOBJ_OUT. 3823 */ 3824static int 3825symlook_default(SymLook *req, const Obj_Entry *refobj) 3826{ 3827 DoneList donelist; 3828 const Objlist_Entry *elm; 3829 SymLook req1; 3830 int res; 3831 3832 donelist_init(&donelist); 3833 symlook_init_from_req(&req1, req); 3834 3835 /* Look first in the referencing object if linked symbolically. */ 3836 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3837 res = symlook_obj(&req1, refobj); 3838 if (res == 0) { 3839 req->sym_out = req1.sym_out; 3840 req->defobj_out = req1.defobj_out; 3841 assert(req->defobj_out != NULL); 3842 } 3843 } 3844 3845 symlook_global(req, &donelist); 3846 3847 /* Search all dlopened DAGs containing the referencing object. */ 3848 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3849 if (req->sym_out != NULL && 3850 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3851 break; 3852 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3853 if (res == 0 && (req->sym_out == NULL || 3854 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3855 req->sym_out = req1.sym_out; 3856 req->defobj_out = req1.defobj_out; 3857 assert(req->defobj_out != NULL); 3858 } 3859 } 3860 3861 /* 3862 * Search the dynamic linker itself, and possibly resolve the 3863 * symbol from there. This is how the application links to 3864 * dynamic linker services such as dlopen. 3865 */ 3866 if (req->sym_out == NULL || 3867 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3868 res = symlook_obj(&req1, &obj_rtld); 3869 if (res == 0) { 3870 req->sym_out = req1.sym_out; 3871 req->defobj_out = req1.defobj_out; 3872 assert(req->defobj_out != NULL); 3873 } 3874 } 3875 3876 return (req->sym_out != NULL ? 0 : ESRCH); 3877} 3878 3879static int 3880symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3881{ 3882 const Elf_Sym *def; 3883 const Obj_Entry *defobj; 3884 const Objlist_Entry *elm; 3885 SymLook req1; 3886 int res; 3887 3888 def = NULL; 3889 defobj = NULL; 3890 STAILQ_FOREACH(elm, objlist, link) { 3891 if (donelist_check(dlp, elm->obj)) 3892 continue; 3893 symlook_init_from_req(&req1, req); 3894 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3895 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3896 def = req1.sym_out; 3897 defobj = req1.defobj_out; 3898 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3899 break; 3900 } 3901 } 3902 } 3903 if (def != NULL) { 3904 req->sym_out = def; 3905 req->defobj_out = defobj; 3906 return (0); 3907 } 3908 return (ESRCH); 3909} 3910 3911/* 3912 * Search the chain of DAGS cointed to by the given Needed_Entry 3913 * for a symbol of the given name. Each DAG is scanned completely 3914 * before advancing to the next one. Returns a pointer to the symbol, 3915 * or NULL if no definition was found. 3916 */ 3917static int 3918symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3919{ 3920 const Elf_Sym *def; 3921 const Needed_Entry *n; 3922 const Obj_Entry *defobj; 3923 SymLook req1; 3924 int res; 3925 3926 def = NULL; 3927 defobj = NULL; 3928 symlook_init_from_req(&req1, req); 3929 for (n = needed; n != NULL; n = n->next) { 3930 if (n->obj == NULL || 3931 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3932 continue; 3933 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3934 def = req1.sym_out; 3935 defobj = req1.defobj_out; 3936 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3937 break; 3938 } 3939 } 3940 if (def != NULL) { 3941 req->sym_out = def; 3942 req->defobj_out = defobj; 3943 return (0); 3944 } 3945 return (ESRCH); 3946} 3947 3948/* 3949 * Search the symbol table of a single shared object for a symbol of 3950 * the given name and version, if requested. Returns a pointer to the 3951 * symbol, or NULL if no definition was found. If the object is 3952 * filter, return filtered symbol from filtee. 3953 * 3954 * The symbol's hash value is passed in for efficiency reasons; that 3955 * eliminates many recomputations of the hash value. 3956 */ 3957int 3958symlook_obj(SymLook *req, const Obj_Entry *obj) 3959{ 3960 DoneList donelist; 3961 SymLook req1; 3962 int flags, res, mres; 3963 3964 /* 3965 * If there is at least one valid hash at this point, we prefer to 3966 * use the faster GNU version if available. 3967 */ 3968 if (obj->valid_hash_gnu) 3969 mres = symlook_obj1_gnu(req, obj); 3970 else if (obj->valid_hash_sysv) 3971 mres = symlook_obj1_sysv(req, obj); 3972 else 3973 return (EINVAL); 3974 3975 if (mres == 0) { 3976 if (obj->needed_filtees != NULL) { 3977 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3978 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3979 donelist_init(&donelist); 3980 symlook_init_from_req(&req1, req); 3981 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3982 if (res == 0) { 3983 req->sym_out = req1.sym_out; 3984 req->defobj_out = req1.defobj_out; 3985 } 3986 return (res); 3987 } 3988 if (obj->needed_aux_filtees != NULL) { 3989 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3990 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3991 donelist_init(&donelist); 3992 symlook_init_from_req(&req1, req); 3993 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3994 if (res == 0) { 3995 req->sym_out = req1.sym_out; 3996 req->defobj_out = req1.defobj_out; 3997 return (res); 3998 } 3999 } 4000 } 4001 return (mres); 4002} 4003 4004/* Symbol match routine common to both hash functions */ 4005static bool 4006matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4007 const unsigned long symnum) 4008{ 4009 Elf_Versym verndx; 4010 const Elf_Sym *symp; 4011 const char *strp; 4012 4013 symp = obj->symtab + symnum; 4014 strp = obj->strtab + symp->st_name; 4015 4016 switch (ELF_ST_TYPE(symp->st_info)) { 4017 case STT_FUNC: 4018 case STT_NOTYPE: 4019 case STT_OBJECT: 4020 case STT_COMMON: 4021 case STT_GNU_IFUNC: 4022 if (symp->st_value == 0) 4023 return (false); 4024 /* fallthrough */ 4025 case STT_TLS: 4026 if (symp->st_shndx != SHN_UNDEF) 4027 break; 4028#ifndef __mips__ 4029 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4030 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4031 break; 4032 /* fallthrough */ 4033#endif 4034 default: 4035 return (false); 4036 } 4037 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4038 return (false); 4039 4040 if (req->ventry == NULL) { 4041 if (obj->versyms != NULL) { 4042 verndx = VER_NDX(obj->versyms[symnum]); 4043 if (verndx > obj->vernum) { 4044 _rtld_error( 4045 "%s: symbol %s references wrong version %d", 4046 obj->path, obj->strtab + symnum, verndx); 4047 return (false); 4048 } 4049 /* 4050 * If we are not called from dlsym (i.e. this 4051 * is a normal relocation from unversioned 4052 * binary), accept the symbol immediately if 4053 * it happens to have first version after this 4054 * shared object became versioned. Otherwise, 4055 * if symbol is versioned and not hidden, 4056 * remember it. If it is the only symbol with 4057 * this name exported by the shared object, it 4058 * will be returned as a match by the calling 4059 * function. If symbol is global (verndx < 2) 4060 * accept it unconditionally. 4061 */ 4062 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4063 verndx == VER_NDX_GIVEN) { 4064 result->sym_out = symp; 4065 return (true); 4066 } 4067 else if (verndx >= VER_NDX_GIVEN) { 4068 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4069 == 0) { 4070 if (result->vsymp == NULL) 4071 result->vsymp = symp; 4072 result->vcount++; 4073 } 4074 return (false); 4075 } 4076 } 4077 result->sym_out = symp; 4078 return (true); 4079 } 4080 if (obj->versyms == NULL) { 4081 if (object_match_name(obj, req->ventry->name)) { 4082 _rtld_error("%s: object %s should provide version %s " 4083 "for symbol %s", obj_rtld.path, obj->path, 4084 req->ventry->name, obj->strtab + symnum); 4085 return (false); 4086 } 4087 } else { 4088 verndx = VER_NDX(obj->versyms[symnum]); 4089 if (verndx > obj->vernum) { 4090 _rtld_error("%s: symbol %s references wrong version %d", 4091 obj->path, obj->strtab + symnum, verndx); 4092 return (false); 4093 } 4094 if (obj->vertab[verndx].hash != req->ventry->hash || 4095 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4096 /* 4097 * Version does not match. Look if this is a 4098 * global symbol and if it is not hidden. If 4099 * global symbol (verndx < 2) is available, 4100 * use it. Do not return symbol if we are 4101 * called by dlvsym, because dlvsym looks for 4102 * a specific version and default one is not 4103 * what dlvsym wants. 4104 */ 4105 if ((req->flags & SYMLOOK_DLSYM) || 4106 (verndx >= VER_NDX_GIVEN) || 4107 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4108 return (false); 4109 } 4110 } 4111 result->sym_out = symp; 4112 return (true); 4113} 4114 4115/* 4116 * Search for symbol using SysV hash function. 4117 * obj->buckets is known not to be NULL at this point; the test for this was 4118 * performed with the obj->valid_hash_sysv assignment. 4119 */ 4120static int 4121symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4122{ 4123 unsigned long symnum; 4124 Sym_Match_Result matchres; 4125 4126 matchres.sym_out = NULL; 4127 matchres.vsymp = NULL; 4128 matchres.vcount = 0; 4129 4130 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4131 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4132 if (symnum >= obj->nchains) 4133 return (ESRCH); /* Bad object */ 4134 4135 if (matched_symbol(req, obj, &matchres, symnum)) { 4136 req->sym_out = matchres.sym_out; 4137 req->defobj_out = obj; 4138 return (0); 4139 } 4140 } 4141 if (matchres.vcount == 1) { 4142 req->sym_out = matchres.vsymp; 4143 req->defobj_out = obj; 4144 return (0); 4145 } 4146 return (ESRCH); 4147} 4148 4149/* Search for symbol using GNU hash function */ 4150static int 4151symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4152{ 4153 Elf_Addr bloom_word; 4154 const Elf32_Word *hashval; 4155 Elf32_Word bucket; 4156 Sym_Match_Result matchres; 4157 unsigned int h1, h2; 4158 unsigned long symnum; 4159 4160 matchres.sym_out = NULL; 4161 matchres.vsymp = NULL; 4162 matchres.vcount = 0; 4163 4164 /* Pick right bitmask word from Bloom filter array */ 4165 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4166 obj->maskwords_bm_gnu]; 4167 4168 /* Calculate modulus word size of gnu hash and its derivative */ 4169 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4170 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4171 4172 /* Filter out the "definitely not in set" queries */ 4173 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4174 return (ESRCH); 4175 4176 /* Locate hash chain and corresponding value element*/ 4177 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4178 if (bucket == 0) 4179 return (ESRCH); 4180 hashval = &obj->chain_zero_gnu[bucket]; 4181 do { 4182 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4183 symnum = hashval - obj->chain_zero_gnu; 4184 if (matched_symbol(req, obj, &matchres, symnum)) { 4185 req->sym_out = matchres.sym_out; 4186 req->defobj_out = obj; 4187 return (0); 4188 } 4189 } 4190 } while ((*hashval++ & 1) == 0); 4191 if (matchres.vcount == 1) { 4192 req->sym_out = matchres.vsymp; 4193 req->defobj_out = obj; 4194 return (0); 4195 } 4196 return (ESRCH); 4197} 4198 4199static void 4200trace_loaded_objects(Obj_Entry *obj) 4201{ 4202 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4203 int c; 4204 4205 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4206 main_local = ""; 4207 4208 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4209 fmt1 = "\t%o => %p (%x)\n"; 4210 4211 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4212 fmt2 = "\t%o (%x)\n"; 4213 4214 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4215 4216 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4217 Needed_Entry *needed; 4218 char *name, *path; 4219 bool is_lib; 4220 4221 if (obj->marker) 4222 continue; 4223 if (list_containers && obj->needed != NULL) 4224 rtld_printf("%s:\n", obj->path); 4225 for (needed = obj->needed; needed; needed = needed->next) { 4226 if (needed->obj != NULL) { 4227 if (needed->obj->traced && !list_containers) 4228 continue; 4229 needed->obj->traced = true; 4230 path = needed->obj->path; 4231 } else 4232 path = "not found"; 4233 4234 name = (char *)obj->strtab + needed->name; 4235 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4236 4237 fmt = is_lib ? fmt1 : fmt2; 4238 while ((c = *fmt++) != '\0') { 4239 switch (c) { 4240 default: 4241 rtld_putchar(c); 4242 continue; 4243 case '\\': 4244 switch (c = *fmt) { 4245 case '\0': 4246 continue; 4247 case 'n': 4248 rtld_putchar('\n'); 4249 break; 4250 case 't': 4251 rtld_putchar('\t'); 4252 break; 4253 } 4254 break; 4255 case '%': 4256 switch (c = *fmt) { 4257 case '\0': 4258 continue; 4259 case '%': 4260 default: 4261 rtld_putchar(c); 4262 break; 4263 case 'A': 4264 rtld_putstr(main_local); 4265 break; 4266 case 'a': 4267 rtld_putstr(obj_main->path); 4268 break; 4269 case 'o': 4270 rtld_putstr(name); 4271 break; 4272#if 0 4273 case 'm': 4274 rtld_printf("%d", sodp->sod_major); 4275 break; 4276 case 'n': 4277 rtld_printf("%d", sodp->sod_minor); 4278 break; 4279#endif 4280 case 'p': 4281 rtld_putstr(path); 4282 break; 4283 case 'x': 4284 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4285 0); 4286 break; 4287 } 4288 break; 4289 } 4290 ++fmt; 4291 } 4292 } 4293 } 4294} 4295 4296/* 4297 * Unload a dlopened object and its dependencies from memory and from 4298 * our data structures. It is assumed that the DAG rooted in the 4299 * object has already been unreferenced, and that the object has a 4300 * reference count of 0. 4301 */ 4302static void 4303unload_object(Obj_Entry *root) 4304{ 4305 Obj_Entry *obj, *obj1; 4306 4307 assert(root->refcount == 0); 4308 4309 /* 4310 * Pass over the DAG removing unreferenced objects from 4311 * appropriate lists. 4312 */ 4313 unlink_object(root); 4314 4315 /* Unmap all objects that are no longer referenced. */ 4316 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4317 if (obj->marker || obj->refcount != 0) 4318 continue; 4319 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4320 obj->mapsize, 0, obj->path); 4321 dbg("unloading \"%s\"", obj->path); 4322 unload_filtees(root); 4323 munmap(obj->mapbase, obj->mapsize); 4324 linkmap_delete(obj); 4325 TAILQ_REMOVE(&obj_list, obj, next); 4326 obj_count--; 4327 obj_free(obj); 4328 } 4329} 4330 4331static void 4332unlink_object(Obj_Entry *root) 4333{ 4334 Objlist_Entry *elm; 4335 4336 if (root->refcount == 0) { 4337 /* Remove the object from the RTLD_GLOBAL list. */ 4338 objlist_remove(&list_global, root); 4339 4340 /* Remove the object from all objects' DAG lists. */ 4341 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4342 objlist_remove(&elm->obj->dldags, root); 4343 if (elm->obj != root) 4344 unlink_object(elm->obj); 4345 } 4346 } 4347} 4348 4349static void 4350ref_dag(Obj_Entry *root) 4351{ 4352 Objlist_Entry *elm; 4353 4354 assert(root->dag_inited); 4355 STAILQ_FOREACH(elm, &root->dagmembers, link) 4356 elm->obj->refcount++; 4357} 4358 4359static void 4360unref_dag(Obj_Entry *root) 4361{ 4362 Objlist_Entry *elm; 4363 4364 assert(root->dag_inited); 4365 STAILQ_FOREACH(elm, &root->dagmembers, link) 4366 elm->obj->refcount--; 4367} 4368 4369/* 4370 * Common code for MD __tls_get_addr(). 4371 */ 4372static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4373static void * 4374tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4375{ 4376 Elf_Addr *newdtv, *dtv; 4377 RtldLockState lockstate; 4378 int to_copy; 4379 4380 dtv = *dtvp; 4381 /* Check dtv generation in case new modules have arrived */ 4382 if (dtv[0] != tls_dtv_generation) { 4383 wlock_acquire(rtld_bind_lock, &lockstate); 4384 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4385 to_copy = dtv[1]; 4386 if (to_copy > tls_max_index) 4387 to_copy = tls_max_index; 4388 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4389 newdtv[0] = tls_dtv_generation; 4390 newdtv[1] = tls_max_index; 4391 free(dtv); 4392 lock_release(rtld_bind_lock, &lockstate); 4393 dtv = *dtvp = newdtv; 4394 } 4395 4396 /* Dynamically allocate module TLS if necessary */ 4397 if (dtv[index + 1] == 0) { 4398 /* Signal safe, wlock will block out signals. */ 4399 wlock_acquire(rtld_bind_lock, &lockstate); 4400 if (!dtv[index + 1]) 4401 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4402 lock_release(rtld_bind_lock, &lockstate); 4403 } 4404 return ((void *)(dtv[index + 1] + offset)); 4405} 4406 4407void * 4408tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4409{ 4410 Elf_Addr *dtv; 4411 4412 dtv = *dtvp; 4413 /* Check dtv generation in case new modules have arrived */ 4414 if (__predict_true(dtv[0] == tls_dtv_generation && 4415 dtv[index + 1] != 0)) 4416 return ((void *)(dtv[index + 1] + offset)); 4417 return (tls_get_addr_slow(dtvp, index, offset)); 4418} 4419 4420#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4421 4422/* 4423 * Allocate Static TLS using the Variant I method. 4424 */ 4425void * 4426allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4427{ 4428 Obj_Entry *obj; 4429 char *tcb; 4430 Elf_Addr **tls; 4431 Elf_Addr *dtv; 4432 Elf_Addr addr; 4433 int i; 4434 4435 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4436 return (oldtcb); 4437 4438 assert(tcbsize >= TLS_TCB_SIZE); 4439 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4440 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4441 4442 if (oldtcb != NULL) { 4443 memcpy(tls, oldtcb, tls_static_space); 4444 free(oldtcb); 4445 4446 /* Adjust the DTV. */ 4447 dtv = tls[0]; 4448 for (i = 0; i < dtv[1]; i++) { 4449 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4450 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4451 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4452 } 4453 } 4454 } else { 4455 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4456 tls[0] = dtv; 4457 dtv[0] = tls_dtv_generation; 4458 dtv[1] = tls_max_index; 4459 4460 for (obj = globallist_curr(objs); obj != NULL; 4461 obj = globallist_next(obj)) { 4462 if (obj->tlsoffset > 0) { 4463 addr = (Elf_Addr)tls + obj->tlsoffset; 4464 if (obj->tlsinitsize > 0) 4465 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4466 if (obj->tlssize > obj->tlsinitsize) 4467 memset((void*) (addr + obj->tlsinitsize), 0, 4468 obj->tlssize - obj->tlsinitsize); 4469 dtv[obj->tlsindex + 1] = addr; 4470 } 4471 } 4472 } 4473 4474 return (tcb); 4475} 4476 4477void 4478free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4479{ 4480 Elf_Addr *dtv; 4481 Elf_Addr tlsstart, tlsend; 4482 int dtvsize, i; 4483 4484 assert(tcbsize >= TLS_TCB_SIZE); 4485 4486 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4487 tlsend = tlsstart + tls_static_space; 4488 4489 dtv = *(Elf_Addr **)tlsstart; 4490 dtvsize = dtv[1]; 4491 for (i = 0; i < dtvsize; i++) { 4492 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4493 free((void*)dtv[i+2]); 4494 } 4495 } 4496 free(dtv); 4497 free(tcb); 4498} 4499 4500#endif 4501 4502#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4503 4504/* 4505 * Allocate Static TLS using the Variant II method. 4506 */ 4507void * 4508allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4509{ 4510 Obj_Entry *obj; 4511 size_t size, ralign; 4512 char *tls; 4513 Elf_Addr *dtv, *olddtv; 4514 Elf_Addr segbase, oldsegbase, addr; 4515 int i; 4516 4517 ralign = tcbalign; 4518 if (tls_static_max_align > ralign) 4519 ralign = tls_static_max_align; 4520 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4521 4522 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4523 tls = malloc_aligned(size, ralign); 4524 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4525 4526 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4527 ((Elf_Addr*)segbase)[0] = segbase; 4528 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4529 4530 dtv[0] = tls_dtv_generation; 4531 dtv[1] = tls_max_index; 4532 4533 if (oldtls) { 4534 /* 4535 * Copy the static TLS block over whole. 4536 */ 4537 oldsegbase = (Elf_Addr) oldtls; 4538 memcpy((void *)(segbase - tls_static_space), 4539 (const void *)(oldsegbase - tls_static_space), 4540 tls_static_space); 4541 4542 /* 4543 * If any dynamic TLS blocks have been created tls_get_addr(), 4544 * move them over. 4545 */ 4546 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4547 for (i = 0; i < olddtv[1]; i++) { 4548 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4549 dtv[i+2] = olddtv[i+2]; 4550 olddtv[i+2] = 0; 4551 } 4552 } 4553 4554 /* 4555 * We assume that this block was the one we created with 4556 * allocate_initial_tls(). 4557 */ 4558 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4559 } else { 4560 obj = objs; 4561 TAILQ_FOREACH_FROM(obj, &obj_list, next) { 4562 if (obj->marker || obj->tlsoffset == 0) 4563 continue; 4564 addr = segbase - obj->tlsoffset; 4565 memset((void*) (addr + obj->tlsinitsize), 4566 0, obj->tlssize - obj->tlsinitsize); 4567 if (obj->tlsinit) 4568 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4569 dtv[obj->tlsindex + 1] = addr; 4570 } 4571 } 4572 4573 return (void*) segbase; 4574} 4575 4576void 4577free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4578{ 4579 Elf_Addr* dtv; 4580 size_t size, ralign; 4581 int dtvsize, i; 4582 Elf_Addr tlsstart, tlsend; 4583 4584 /* 4585 * Figure out the size of the initial TLS block so that we can 4586 * find stuff which ___tls_get_addr() allocated dynamically. 4587 */ 4588 ralign = tcbalign; 4589 if (tls_static_max_align > ralign) 4590 ralign = tls_static_max_align; 4591 size = round(tls_static_space, ralign); 4592 4593 dtv = ((Elf_Addr**)tls)[1]; 4594 dtvsize = dtv[1]; 4595 tlsend = (Elf_Addr) tls; 4596 tlsstart = tlsend - size; 4597 for (i = 0; i < dtvsize; i++) { 4598 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4599 free_aligned((void *)dtv[i + 2]); 4600 } 4601 } 4602 4603 free_aligned((void *)tlsstart); 4604 free((void*) dtv); 4605} 4606 4607#endif 4608 4609/* 4610 * Allocate TLS block for module with given index. 4611 */ 4612void * 4613allocate_module_tls(int index) 4614{ 4615 Obj_Entry* obj; 4616 char* p; 4617 4618 TAILQ_FOREACH(obj, &obj_list, next) { 4619 if (obj->marker) 4620 continue; 4621 if (obj->tlsindex == index) 4622 break; 4623 } 4624 if (!obj) { 4625 _rtld_error("Can't find module with TLS index %d", index); 4626 rtld_die(); 4627 } 4628 4629 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4630 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4631 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4632 4633 return p; 4634} 4635 4636bool 4637allocate_tls_offset(Obj_Entry *obj) 4638{ 4639 size_t off; 4640 4641 if (obj->tls_done) 4642 return true; 4643 4644 if (obj->tlssize == 0) { 4645 obj->tls_done = true; 4646 return true; 4647 } 4648 4649 if (tls_last_offset == 0) 4650 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4651 else 4652 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4653 obj->tlssize, obj->tlsalign); 4654 4655 /* 4656 * If we have already fixed the size of the static TLS block, we 4657 * must stay within that size. When allocating the static TLS, we 4658 * leave a small amount of space spare to be used for dynamically 4659 * loading modules which use static TLS. 4660 */ 4661 if (tls_static_space != 0) { 4662 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4663 return false; 4664 } else if (obj->tlsalign > tls_static_max_align) { 4665 tls_static_max_align = obj->tlsalign; 4666 } 4667 4668 tls_last_offset = obj->tlsoffset = off; 4669 tls_last_size = obj->tlssize; 4670 obj->tls_done = true; 4671 4672 return true; 4673} 4674 4675void 4676free_tls_offset(Obj_Entry *obj) 4677{ 4678 4679 /* 4680 * If we were the last thing to allocate out of the static TLS 4681 * block, we give our space back to the 'allocator'. This is a 4682 * simplistic workaround to allow libGL.so.1 to be loaded and 4683 * unloaded multiple times. 4684 */ 4685 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4686 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4687 tls_last_offset -= obj->tlssize; 4688 tls_last_size = 0; 4689 } 4690} 4691 4692void * 4693_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4694{ 4695 void *ret; 4696 RtldLockState lockstate; 4697 4698 wlock_acquire(rtld_bind_lock, &lockstate); 4699 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4700 tcbsize, tcbalign); 4701 lock_release(rtld_bind_lock, &lockstate); 4702 return (ret); 4703} 4704 4705void 4706_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4707{ 4708 RtldLockState lockstate; 4709 4710 wlock_acquire(rtld_bind_lock, &lockstate); 4711 free_tls(tcb, tcbsize, tcbalign); 4712 lock_release(rtld_bind_lock, &lockstate); 4713} 4714 4715static void 4716object_add_name(Obj_Entry *obj, const char *name) 4717{ 4718 Name_Entry *entry; 4719 size_t len; 4720 4721 len = strlen(name); 4722 entry = malloc(sizeof(Name_Entry) + len); 4723 4724 if (entry != NULL) { 4725 strcpy(entry->name, name); 4726 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4727 } 4728} 4729 4730static int 4731object_match_name(const Obj_Entry *obj, const char *name) 4732{ 4733 Name_Entry *entry; 4734 4735 STAILQ_FOREACH(entry, &obj->names, link) { 4736 if (strcmp(name, entry->name) == 0) 4737 return (1); 4738 } 4739 return (0); 4740} 4741 4742static Obj_Entry * 4743locate_dependency(const Obj_Entry *obj, const char *name) 4744{ 4745 const Objlist_Entry *entry; 4746 const Needed_Entry *needed; 4747 4748 STAILQ_FOREACH(entry, &list_main, link) { 4749 if (object_match_name(entry->obj, name)) 4750 return entry->obj; 4751 } 4752 4753 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4754 if (strcmp(obj->strtab + needed->name, name) == 0 || 4755 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4756 /* 4757 * If there is DT_NEEDED for the name we are looking for, 4758 * we are all set. Note that object might not be found if 4759 * dependency was not loaded yet, so the function can 4760 * return NULL here. This is expected and handled 4761 * properly by the caller. 4762 */ 4763 return (needed->obj); 4764 } 4765 } 4766 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4767 obj->path, name); 4768 rtld_die(); 4769} 4770 4771static int 4772check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4773 const Elf_Vernaux *vna) 4774{ 4775 const Elf_Verdef *vd; 4776 const char *vername; 4777 4778 vername = refobj->strtab + vna->vna_name; 4779 vd = depobj->verdef; 4780 if (vd == NULL) { 4781 _rtld_error("%s: version %s required by %s not defined", 4782 depobj->path, vername, refobj->path); 4783 return (-1); 4784 } 4785 for (;;) { 4786 if (vd->vd_version != VER_DEF_CURRENT) { 4787 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4788 depobj->path, vd->vd_version); 4789 return (-1); 4790 } 4791 if (vna->vna_hash == vd->vd_hash) { 4792 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4793 ((char *)vd + vd->vd_aux); 4794 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4795 return (0); 4796 } 4797 if (vd->vd_next == 0) 4798 break; 4799 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4800 } 4801 if (vna->vna_flags & VER_FLG_WEAK) 4802 return (0); 4803 _rtld_error("%s: version %s required by %s not found", 4804 depobj->path, vername, refobj->path); 4805 return (-1); 4806} 4807 4808static int 4809rtld_verify_object_versions(Obj_Entry *obj) 4810{ 4811 const Elf_Verneed *vn; 4812 const Elf_Verdef *vd; 4813 const Elf_Verdaux *vda; 4814 const Elf_Vernaux *vna; 4815 const Obj_Entry *depobj; 4816 int maxvernum, vernum; 4817 4818 if (obj->ver_checked) 4819 return (0); 4820 obj->ver_checked = true; 4821 4822 maxvernum = 0; 4823 /* 4824 * Walk over defined and required version records and figure out 4825 * max index used by any of them. Do very basic sanity checking 4826 * while there. 4827 */ 4828 vn = obj->verneed; 4829 while (vn != NULL) { 4830 if (vn->vn_version != VER_NEED_CURRENT) { 4831 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4832 obj->path, vn->vn_version); 4833 return (-1); 4834 } 4835 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4836 for (;;) { 4837 vernum = VER_NEED_IDX(vna->vna_other); 4838 if (vernum > maxvernum) 4839 maxvernum = vernum; 4840 if (vna->vna_next == 0) 4841 break; 4842 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4843 } 4844 if (vn->vn_next == 0) 4845 break; 4846 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4847 } 4848 4849 vd = obj->verdef; 4850 while (vd != NULL) { 4851 if (vd->vd_version != VER_DEF_CURRENT) { 4852 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4853 obj->path, vd->vd_version); 4854 return (-1); 4855 } 4856 vernum = VER_DEF_IDX(vd->vd_ndx); 4857 if (vernum > maxvernum) 4858 maxvernum = vernum; 4859 if (vd->vd_next == 0) 4860 break; 4861 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4862 } 4863 4864 if (maxvernum == 0) 4865 return (0); 4866 4867 /* 4868 * Store version information in array indexable by version index. 4869 * Verify that object version requirements are satisfied along the 4870 * way. 4871 */ 4872 obj->vernum = maxvernum + 1; 4873 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4874 4875 vd = obj->verdef; 4876 while (vd != NULL) { 4877 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4878 vernum = VER_DEF_IDX(vd->vd_ndx); 4879 assert(vernum <= maxvernum); 4880 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4881 obj->vertab[vernum].hash = vd->vd_hash; 4882 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4883 obj->vertab[vernum].file = NULL; 4884 obj->vertab[vernum].flags = 0; 4885 } 4886 if (vd->vd_next == 0) 4887 break; 4888 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4889 } 4890 4891 vn = obj->verneed; 4892 while (vn != NULL) { 4893 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4894 if (depobj == NULL) 4895 return (-1); 4896 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4897 for (;;) { 4898 if (check_object_provided_version(obj, depobj, vna)) 4899 return (-1); 4900 vernum = VER_NEED_IDX(vna->vna_other); 4901 assert(vernum <= maxvernum); 4902 obj->vertab[vernum].hash = vna->vna_hash; 4903 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4904 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4905 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4906 VER_INFO_HIDDEN : 0; 4907 if (vna->vna_next == 0) 4908 break; 4909 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4910 } 4911 if (vn->vn_next == 0) 4912 break; 4913 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4914 } 4915 return 0; 4916} 4917 4918static int 4919rtld_verify_versions(const Objlist *objlist) 4920{ 4921 Objlist_Entry *entry; 4922 int rc; 4923 4924 rc = 0; 4925 STAILQ_FOREACH(entry, objlist, link) { 4926 /* 4927 * Skip dummy objects or objects that have their version requirements 4928 * already checked. 4929 */ 4930 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4931 continue; 4932 if (rtld_verify_object_versions(entry->obj) == -1) { 4933 rc = -1; 4934 if (ld_tracing == NULL) 4935 break; 4936 } 4937 } 4938 if (rc == 0 || ld_tracing != NULL) 4939 rc = rtld_verify_object_versions(&obj_rtld); 4940 return rc; 4941} 4942 4943const Ver_Entry * 4944fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4945{ 4946 Elf_Versym vernum; 4947 4948 if (obj->vertab) { 4949 vernum = VER_NDX(obj->versyms[symnum]); 4950 if (vernum >= obj->vernum) { 4951 _rtld_error("%s: symbol %s has wrong verneed value %d", 4952 obj->path, obj->strtab + symnum, vernum); 4953 } else if (obj->vertab[vernum].hash != 0) { 4954 return &obj->vertab[vernum]; 4955 } 4956 } 4957 return NULL; 4958} 4959 4960int 4961_rtld_get_stack_prot(void) 4962{ 4963 4964 return (stack_prot); 4965} 4966 4967int 4968_rtld_is_dlopened(void *arg) 4969{ 4970 Obj_Entry *obj; 4971 RtldLockState lockstate; 4972 int res; 4973 4974 rlock_acquire(rtld_bind_lock, &lockstate); 4975 obj = dlcheck(arg); 4976 if (obj == NULL) 4977 obj = obj_from_addr(arg); 4978 if (obj == NULL) { 4979 _rtld_error("No shared object contains address"); 4980 lock_release(rtld_bind_lock, &lockstate); 4981 return (-1); 4982 } 4983 res = obj->dlopened ? 1 : 0; 4984 lock_release(rtld_bind_lock, &lockstate); 4985 return (res); 4986} 4987 4988static void 4989map_stacks_exec(RtldLockState *lockstate) 4990{ 4991 void (*thr_map_stacks_exec)(void); 4992 4993 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4994 return; 4995 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4996 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4997 if (thr_map_stacks_exec != NULL) { 4998 stack_prot |= PROT_EXEC; 4999 thr_map_stacks_exec(); 5000 } 5001} 5002 5003void 5004symlook_init(SymLook *dst, const char *name) 5005{ 5006 5007 bzero(dst, sizeof(*dst)); 5008 dst->name = name; 5009 dst->hash = elf_hash(name); 5010 dst->hash_gnu = gnu_hash(name); 5011} 5012 5013static void 5014symlook_init_from_req(SymLook *dst, const SymLook *src) 5015{ 5016 5017 dst->name = src->name; 5018 dst->hash = src->hash; 5019 dst->hash_gnu = src->hash_gnu; 5020 dst->ventry = src->ventry; 5021 dst->flags = src->flags; 5022 dst->defobj_out = NULL; 5023 dst->sym_out = NULL; 5024 dst->lockstate = src->lockstate; 5025} 5026 5027/* 5028 * Overrides for libc_pic-provided functions. 5029 */ 5030 5031int 5032__getosreldate(void) 5033{ 5034 size_t len; 5035 int oid[2]; 5036 int error, osrel; 5037 5038 if (osreldate != 0) 5039 return (osreldate); 5040 5041 oid[0] = CTL_KERN; 5042 oid[1] = KERN_OSRELDATE; 5043 osrel = 0; 5044 len = sizeof(osrel); 5045 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5046 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5047 osreldate = osrel; 5048 return (osreldate); 5049} 5050 5051void 5052exit(int status) 5053{ 5054 5055 _exit(status); 5056} 5057 5058void (*__cleanup)(void); 5059int __isthreaded = 0; 5060int _thread_autoinit_dummy_decl = 1; 5061 5062/* 5063 * No unresolved symbols for rtld. 5064 */ 5065void 5066__pthread_cxa_finalize(struct dl_phdr_info *a) 5067{ 5068} 5069 5070void 5071__stack_chk_fail(void) 5072{ 5073 5074 _rtld_error("stack overflow detected; terminated"); 5075 rtld_die(); 5076} 5077__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5078 5079void 5080__chk_fail(void) 5081{ 5082 5083 _rtld_error("buffer overflow detected; terminated"); 5084 rtld_die(); 5085} 5086 5087const char * 5088rtld_strerror(int errnum) 5089{ 5090 5091 if (errnum < 0 || errnum >= sys_nerr) 5092 return ("Unknown error"); 5093 return (sys_errlist[errnum]); 5094} 5095