rtld.c revision 282412
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 282412 2015-05-04 08:19:12Z kib $ 29 */ 30 31/* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37#ifndef __GNUC__ 38#error "GCC is needed to compile this file" 39#endif 40 41#include <sys/param.h> 42#include <sys/mount.h> 43#include <sys/mman.h> 44#include <sys/stat.h> 45#include <sys/sysctl.h> 46#include <sys/uio.h> 47#include <sys/utsname.h> 48#include <sys/ktrace.h> 49 50#include <dlfcn.h> 51#include <err.h> 52#include <errno.h> 53#include <fcntl.h> 54#include <stdarg.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#include <unistd.h> 59 60#include "debug.h" 61#include "rtld.h" 62#include "libmap.h" 63#include "rtld_tls.h" 64#include "rtld_printf.h" 65#include "notes.h" 66 67#ifndef COMPAT_32BIT 68#define PATH_RTLD "/libexec/ld-elf.so.1" 69#else 70#define PATH_RTLD "/libexec/ld-elf32.so.1" 71#endif 72 73/* Types. */ 74typedef void (*func_ptr_type)(); 75typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77/* 78 * Function declarations. 79 */ 80static const char *basename(const char *); 81static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **, const Elf_Dyn **); 83static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 84 const Elf_Dyn *); 85static void digest_dynamic(Obj_Entry *, int); 86static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 87static Obj_Entry *dlcheck(void *); 88static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92static bool donelist_check(DoneList *, const Obj_Entry *); 93static void errmsg_restore(char *); 94static char *errmsg_save(void); 95static void *fill_search_info(const char *, size_t, void *); 96static char *find_library(const char *, const Obj_Entry *); 97static const char *gethints(bool); 98static void init_dag(Obj_Entry *); 99static void init_pagesizes(Elf_Auxinfo **aux_info); 100static void init_rtld(caddr_t, Elf_Auxinfo **); 101static void initlist_add_neededs(Needed_Entry *, Objlist *); 102static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103static void linkmap_add(Obj_Entry *); 104static void linkmap_delete(Obj_Entry *); 105static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106static void unload_filtees(Obj_Entry *); 107static int load_needed_objects(Obj_Entry *, int); 108static int load_preload_objects(void); 109static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110static void map_stacks_exec(RtldLockState *); 111static Obj_Entry *obj_from_addr(const void *); 112static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113static void objlist_call_init(Objlist *, RtldLockState *); 114static void objlist_clear(Objlist *); 115static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116static void objlist_init(Objlist *); 117static void objlist_push_head(Objlist *, Obj_Entry *); 118static void objlist_push_tail(Objlist *, Obj_Entry *); 119static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120static void objlist_remove(Objlist *, Obj_Entry *); 121static void *path_enumerate(const char *, path_enum_proc, void *); 122static int relocate_object_dag(Obj_Entry *root, bool bind_now, 123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 124static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 125 int flags, RtldLockState *lockstate); 126static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 127 RtldLockState *); 128static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 129 int flags, RtldLockState *lockstate); 130static int rtld_dirname(const char *, char *); 131static int rtld_dirname_abs(const char *, char *); 132static void *rtld_dlopen(const char *name, int fd, int mode); 133static void rtld_exit(void); 134static char *search_library_path(const char *, const char *); 135static const void **get_program_var_addr(const char *, RtldLockState *); 136static void set_program_var(const char *, const void *); 137static int symlook_default(SymLook *, const Obj_Entry *refobj); 138static int symlook_global(SymLook *, DoneList *); 139static void symlook_init_from_req(SymLook *, const SymLook *); 140static int symlook_list(SymLook *, const Objlist *, DoneList *); 141static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 142static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 143static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 144static void trace_loaded_objects(Obj_Entry *); 145static void unlink_object(Obj_Entry *); 146static void unload_object(Obj_Entry *); 147static void unref_dag(Obj_Entry *); 148static void ref_dag(Obj_Entry *); 149static char *origin_subst_one(Obj_Entry *, char *, const char *, 150 const char *, bool); 151static char *origin_subst(Obj_Entry *, char *); 152static bool obj_resolve_origin(Obj_Entry *obj); 153static void preinit_main(void); 154static int rtld_verify_versions(const Objlist *); 155static int rtld_verify_object_versions(Obj_Entry *); 156static void object_add_name(Obj_Entry *, const char *); 157static int object_match_name(const Obj_Entry *, const char *); 158static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 159static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 160 struct dl_phdr_info *phdr_info); 161static uint32_t gnu_hash(const char *); 162static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 163 const unsigned long); 164 165void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 166void _r_debug_postinit(struct link_map *) __noinline __exported; 167 168/* 169 * Data declarations. 170 */ 171static char *error_message; /* Message for dlerror(), or NULL */ 172struct r_debug r_debug __exported; /* for GDB; */ 173static bool libmap_disable; /* Disable libmap */ 174static bool ld_loadfltr; /* Immediate filters processing */ 175static char *libmap_override; /* Maps to use in addition to libmap.conf */ 176static bool trust; /* False for setuid and setgid programs */ 177static bool dangerous_ld_env; /* True if environment variables have been 178 used to affect the libraries loaded */ 179static char *ld_bind_now; /* Environment variable for immediate binding */ 180static char *ld_debug; /* Environment variable for debugging */ 181static char *ld_library_path; /* Environment variable for search path */ 182static char *ld_preload; /* Environment variable for libraries to 183 load first */ 184static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 185static char *ld_tracing; /* Called from ldd to print libs */ 186static char *ld_utrace; /* Use utrace() to log events. */ 187static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 188static Obj_Entry **obj_tail; /* Link field of last object in list */ 189static Obj_Entry *obj_main; /* The main program shared object */ 190static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 191static unsigned int obj_count; /* Number of objects in obj_list */ 192static unsigned int obj_loads; /* Number of objects in obj_list */ 193 194static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 195 STAILQ_HEAD_INITIALIZER(list_global); 196static Objlist list_main = /* Objects loaded at program startup */ 197 STAILQ_HEAD_INITIALIZER(list_main); 198static Objlist list_fini = /* Objects needing fini() calls */ 199 STAILQ_HEAD_INITIALIZER(list_fini); 200 201Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 202 203#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 204 205extern Elf_Dyn _DYNAMIC; 206#pragma weak _DYNAMIC 207#ifndef RTLD_IS_DYNAMIC 208#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 209#endif 210 211int dlclose(void *) __exported; 212char *dlerror(void) __exported; 213void *dlopen(const char *, int) __exported; 214void *fdlopen(int, int) __exported; 215void *dlsym(void *, const char *) __exported; 216dlfunc_t dlfunc(void *, const char *) __exported; 217void *dlvsym(void *, const char *, const char *) __exported; 218int dladdr(const void *, Dl_info *) __exported; 219void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 220 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 221int dlinfo(void *, int , void *) __exported; 222int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 223int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 224int _rtld_get_stack_prot(void) __exported; 225int _rtld_is_dlopened(void *) __exported; 226void _rtld_error(const char *, ...) __exported; 227 228int npagesizes, osreldate; 229size_t *pagesizes; 230 231long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 232 233static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 234static int max_stack_flags; 235 236/* 237 * Global declarations normally provided by crt1. The dynamic linker is 238 * not built with crt1, so we have to provide them ourselves. 239 */ 240char *__progname; 241char **environ; 242 243/* 244 * Used to pass argc, argv to init functions. 245 */ 246int main_argc; 247char **main_argv; 248 249/* 250 * Globals to control TLS allocation. 251 */ 252size_t tls_last_offset; /* Static TLS offset of last module */ 253size_t tls_last_size; /* Static TLS size of last module */ 254size_t tls_static_space; /* Static TLS space allocated */ 255size_t tls_static_max_align; 256int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 257int tls_max_index = 1; /* Largest module index allocated */ 258 259bool ld_library_path_rpath = false; 260 261/* 262 * Fill in a DoneList with an allocation large enough to hold all of 263 * the currently-loaded objects. Keep this as a macro since it calls 264 * alloca and we want that to occur within the scope of the caller. 265 */ 266#define donelist_init(dlp) \ 267 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 268 assert((dlp)->objs != NULL), \ 269 (dlp)->num_alloc = obj_count, \ 270 (dlp)->num_used = 0) 271 272#define UTRACE_DLOPEN_START 1 273#define UTRACE_DLOPEN_STOP 2 274#define UTRACE_DLCLOSE_START 3 275#define UTRACE_DLCLOSE_STOP 4 276#define UTRACE_LOAD_OBJECT 5 277#define UTRACE_UNLOAD_OBJECT 6 278#define UTRACE_ADD_RUNDEP 7 279#define UTRACE_PRELOAD_FINISHED 8 280#define UTRACE_INIT_CALL 9 281#define UTRACE_FINI_CALL 10 282 283struct utrace_rtld { 284 char sig[4]; /* 'RTLD' */ 285 int event; 286 void *handle; 287 void *mapbase; /* Used for 'parent' and 'init/fini' */ 288 size_t mapsize; 289 int refcnt; /* Used for 'mode' */ 290 char name[MAXPATHLEN]; 291}; 292 293#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 294 if (ld_utrace != NULL) \ 295 ld_utrace_log(e, h, mb, ms, r, n); \ 296} while (0) 297 298static void 299ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 300 int refcnt, const char *name) 301{ 302 struct utrace_rtld ut; 303 304 ut.sig[0] = 'R'; 305 ut.sig[1] = 'T'; 306 ut.sig[2] = 'L'; 307 ut.sig[3] = 'D'; 308 ut.event = event; 309 ut.handle = handle; 310 ut.mapbase = mapbase; 311 ut.mapsize = mapsize; 312 ut.refcnt = refcnt; 313 bzero(ut.name, sizeof(ut.name)); 314 if (name) 315 strlcpy(ut.name, name, sizeof(ut.name)); 316 utrace(&ut, sizeof(ut)); 317} 318 319/* 320 * Main entry point for dynamic linking. The first argument is the 321 * stack pointer. The stack is expected to be laid out as described 322 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 323 * Specifically, the stack pointer points to a word containing 324 * ARGC. Following that in the stack is a null-terminated sequence 325 * of pointers to argument strings. Then comes a null-terminated 326 * sequence of pointers to environment strings. Finally, there is a 327 * sequence of "auxiliary vector" entries. 328 * 329 * The second argument points to a place to store the dynamic linker's 330 * exit procedure pointer and the third to a place to store the main 331 * program's object. 332 * 333 * The return value is the main program's entry point. 334 */ 335func_ptr_type 336_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 337{ 338 Elf_Auxinfo *aux_info[AT_COUNT]; 339 int i; 340 int argc; 341 char **argv; 342 char **env; 343 Elf_Auxinfo *aux; 344 Elf_Auxinfo *auxp; 345 const char *argv0; 346 Objlist_Entry *entry; 347 Obj_Entry *obj; 348 Obj_Entry **preload_tail; 349 Obj_Entry *last_interposer; 350 Objlist initlist; 351 RtldLockState lockstate; 352 char *library_path_rpath; 353 int mib[2]; 354 size_t len; 355 356 /* 357 * On entry, the dynamic linker itself has not been relocated yet. 358 * Be very careful not to reference any global data until after 359 * init_rtld has returned. It is OK to reference file-scope statics 360 * and string constants, and to call static and global functions. 361 */ 362 363 /* Find the auxiliary vector on the stack. */ 364 argc = *sp++; 365 argv = (char **) sp; 366 sp += argc + 1; /* Skip over arguments and NULL terminator */ 367 env = (char **) sp; 368 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 369 ; 370 aux = (Elf_Auxinfo *) sp; 371 372 /* Digest the auxiliary vector. */ 373 for (i = 0; i < AT_COUNT; i++) 374 aux_info[i] = NULL; 375 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 376 if (auxp->a_type < AT_COUNT) 377 aux_info[auxp->a_type] = auxp; 378 } 379 380 /* Initialize and relocate ourselves. */ 381 assert(aux_info[AT_BASE] != NULL); 382 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 383 384 __progname = obj_rtld.path; 385 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 386 environ = env; 387 main_argc = argc; 388 main_argv = argv; 389 390 if (aux_info[AT_CANARY] != NULL && 391 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 392 i = aux_info[AT_CANARYLEN]->a_un.a_val; 393 if (i > sizeof(__stack_chk_guard)) 394 i = sizeof(__stack_chk_guard); 395 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 396 } else { 397 mib[0] = CTL_KERN; 398 mib[1] = KERN_ARND; 399 400 len = sizeof(__stack_chk_guard); 401 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 402 len != sizeof(__stack_chk_guard)) { 403 /* If sysctl was unsuccessful, use the "terminator canary". */ 404 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 405 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 406 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 407 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 408 } 409 } 410 411 trust = !issetugid(); 412 413 ld_bind_now = getenv(LD_ "BIND_NOW"); 414 /* 415 * If the process is tainted, then we un-set the dangerous environment 416 * variables. The process will be marked as tainted until setuid(2) 417 * is called. If any child process calls setuid(2) we do not want any 418 * future processes to honor the potentially un-safe variables. 419 */ 420 if (!trust) { 421 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 422 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 423 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 424 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 425 _rtld_error("environment corrupt; aborting"); 426 rtld_die(); 427 } 428 } 429 ld_debug = getenv(LD_ "DEBUG"); 430 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 431 libmap_override = getenv(LD_ "LIBMAP"); 432 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 433 ld_preload = getenv(LD_ "PRELOAD"); 434 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 435 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 436 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 437 if (library_path_rpath != NULL) { 438 if (library_path_rpath[0] == 'y' || 439 library_path_rpath[0] == 'Y' || 440 library_path_rpath[0] == '1') 441 ld_library_path_rpath = true; 442 else 443 ld_library_path_rpath = false; 444 } 445 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 446 (ld_library_path != NULL) || (ld_preload != NULL) || 447 (ld_elf_hints_path != NULL) || ld_loadfltr; 448 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 449 ld_utrace = getenv(LD_ "UTRACE"); 450 451 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 452 ld_elf_hints_path = _PATH_ELF_HINTS; 453 454 if (ld_debug != NULL && *ld_debug != '\0') 455 debug = 1; 456 dbg("%s is initialized, base address = %p", __progname, 457 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 458 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 459 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 460 461 dbg("initializing thread locks"); 462 lockdflt_init(); 463 464 /* 465 * Load the main program, or process its program header if it is 466 * already loaded. 467 */ 468 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 469 int fd = aux_info[AT_EXECFD]->a_un.a_val; 470 dbg("loading main program"); 471 obj_main = map_object(fd, argv0, NULL); 472 close(fd); 473 if (obj_main == NULL) 474 rtld_die(); 475 max_stack_flags = obj->stack_flags; 476 } else { /* Main program already loaded. */ 477 const Elf_Phdr *phdr; 478 int phnum; 479 caddr_t entry; 480 481 dbg("processing main program's program header"); 482 assert(aux_info[AT_PHDR] != NULL); 483 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 484 assert(aux_info[AT_PHNUM] != NULL); 485 phnum = aux_info[AT_PHNUM]->a_un.a_val; 486 assert(aux_info[AT_PHENT] != NULL); 487 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 488 assert(aux_info[AT_ENTRY] != NULL); 489 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 490 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 491 rtld_die(); 492 } 493 494 if (aux_info[AT_EXECPATH] != 0) { 495 char *kexecpath; 496 char buf[MAXPATHLEN]; 497 498 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 499 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 500 if (kexecpath[0] == '/') 501 obj_main->path = kexecpath; 502 else if (getcwd(buf, sizeof(buf)) == NULL || 503 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 504 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 505 obj_main->path = xstrdup(argv0); 506 else 507 obj_main->path = xstrdup(buf); 508 } else { 509 dbg("No AT_EXECPATH"); 510 obj_main->path = xstrdup(argv0); 511 } 512 dbg("obj_main path %s", obj_main->path); 513 obj_main->mainprog = true; 514 515 if (aux_info[AT_STACKPROT] != NULL && 516 aux_info[AT_STACKPROT]->a_un.a_val != 0) 517 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 518 519#ifndef COMPAT_32BIT 520 /* 521 * Get the actual dynamic linker pathname from the executable if 522 * possible. (It should always be possible.) That ensures that 523 * gdb will find the right dynamic linker even if a non-standard 524 * one is being used. 525 */ 526 if (obj_main->interp != NULL && 527 strcmp(obj_main->interp, obj_rtld.path) != 0) { 528 free(obj_rtld.path); 529 obj_rtld.path = xstrdup(obj_main->interp); 530 __progname = obj_rtld.path; 531 } 532#endif 533 534 digest_dynamic(obj_main, 0); 535 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 536 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 537 obj_main->dynsymcount); 538 539 linkmap_add(obj_main); 540 linkmap_add(&obj_rtld); 541 542 /* Link the main program into the list of objects. */ 543 *obj_tail = obj_main; 544 obj_tail = &obj_main->next; 545 obj_count++; 546 obj_loads++; 547 548 /* Initialize a fake symbol for resolving undefined weak references. */ 549 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 550 sym_zero.st_shndx = SHN_UNDEF; 551 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 552 553 if (!libmap_disable) 554 libmap_disable = (bool)lm_init(libmap_override); 555 556 dbg("loading LD_PRELOAD libraries"); 557 if (load_preload_objects() == -1) 558 rtld_die(); 559 preload_tail = obj_tail; 560 561 dbg("loading needed objects"); 562 if (load_needed_objects(obj_main, 0) == -1) 563 rtld_die(); 564 565 /* Make a list of all objects loaded at startup. */ 566 last_interposer = obj_main; 567 for (obj = obj_list; obj != NULL; obj = obj->next) { 568 if (obj->z_interpose && obj != obj_main) { 569 objlist_put_after(&list_main, last_interposer, obj); 570 last_interposer = obj; 571 } else { 572 objlist_push_tail(&list_main, obj); 573 } 574 obj->refcount++; 575 } 576 577 dbg("checking for required versions"); 578 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 579 rtld_die(); 580 581 if (ld_tracing) { /* We're done */ 582 trace_loaded_objects(obj_main); 583 exit(0); 584 } 585 586 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 587 dump_relocations(obj_main); 588 exit (0); 589 } 590 591 /* 592 * Processing tls relocations requires having the tls offsets 593 * initialized. Prepare offsets before starting initial 594 * relocation processing. 595 */ 596 dbg("initializing initial thread local storage offsets"); 597 STAILQ_FOREACH(entry, &list_main, link) { 598 /* 599 * Allocate all the initial objects out of the static TLS 600 * block even if they didn't ask for it. 601 */ 602 allocate_tls_offset(entry->obj); 603 } 604 605 if (relocate_objects(obj_main, 606 ld_bind_now != NULL && *ld_bind_now != '\0', 607 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 608 rtld_die(); 609 610 dbg("doing copy relocations"); 611 if (do_copy_relocations(obj_main) == -1) 612 rtld_die(); 613 614 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 615 dump_relocations(obj_main); 616 exit (0); 617 } 618 619 /* 620 * Setup TLS for main thread. This must be done after the 621 * relocations are processed, since tls initialization section 622 * might be the subject for relocations. 623 */ 624 dbg("initializing initial thread local storage"); 625 allocate_initial_tls(obj_list); 626 627 dbg("initializing key program variables"); 628 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 629 set_program_var("environ", env); 630 set_program_var("__elf_aux_vector", aux); 631 632 /* Make a list of init functions to call. */ 633 objlist_init(&initlist); 634 initlist_add_objects(obj_list, preload_tail, &initlist); 635 636 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 637 638 map_stacks_exec(NULL); 639 640 dbg("resolving ifuncs"); 641 if (resolve_objects_ifunc(obj_main, 642 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 643 NULL) == -1) 644 rtld_die(); 645 646 if (!obj_main->crt_no_init) { 647 /* 648 * Make sure we don't call the main program's init and fini 649 * functions for binaries linked with old crt1 which calls 650 * _init itself. 651 */ 652 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 653 obj_main->preinit_array = obj_main->init_array = 654 obj_main->fini_array = (Elf_Addr)NULL; 655 } 656 657 wlock_acquire(rtld_bind_lock, &lockstate); 658 if (obj_main->crt_no_init) 659 preinit_main(); 660 objlist_call_init(&initlist, &lockstate); 661 _r_debug_postinit(&obj_main->linkmap); 662 objlist_clear(&initlist); 663 dbg("loading filtees"); 664 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 665 if (ld_loadfltr || obj->z_loadfltr) 666 load_filtees(obj, 0, &lockstate); 667 } 668 lock_release(rtld_bind_lock, &lockstate); 669 670 dbg("transferring control to program entry point = %p", obj_main->entry); 671 672 /* Return the exit procedure and the program entry point. */ 673 *exit_proc = rtld_exit; 674 *objp = obj_main; 675 return (func_ptr_type) obj_main->entry; 676} 677 678void * 679rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 680{ 681 void *ptr; 682 Elf_Addr target; 683 684 ptr = (void *)make_function_pointer(def, obj); 685 target = ((Elf_Addr (*)(void))ptr)(); 686 return ((void *)target); 687} 688 689Elf_Addr 690_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 691{ 692 const Elf_Rel *rel; 693 const Elf_Sym *def; 694 const Obj_Entry *defobj; 695 Elf_Addr *where; 696 Elf_Addr target; 697 RtldLockState lockstate; 698 699 rlock_acquire(rtld_bind_lock, &lockstate); 700 if (sigsetjmp(lockstate.env, 0) != 0) 701 lock_upgrade(rtld_bind_lock, &lockstate); 702 if (obj->pltrel) 703 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 704 else 705 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 706 707 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 708 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 709 &lockstate); 710 if (def == NULL) 711 rtld_die(); 712 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 713 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 714 else 715 target = (Elf_Addr)(defobj->relocbase + def->st_value); 716 717 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 718 defobj->strtab + def->st_name, basename(obj->path), 719 (void *)target, basename(defobj->path)); 720 721 /* 722 * Write the new contents for the jmpslot. Note that depending on 723 * architecture, the value which we need to return back to the 724 * lazy binding trampoline may or may not be the target 725 * address. The value returned from reloc_jmpslot() is the value 726 * that the trampoline needs. 727 */ 728 target = reloc_jmpslot(where, target, defobj, obj, rel); 729 lock_release(rtld_bind_lock, &lockstate); 730 return target; 731} 732 733/* 734 * Error reporting function. Use it like printf. If formats the message 735 * into a buffer, and sets things up so that the next call to dlerror() 736 * will return the message. 737 */ 738void 739_rtld_error(const char *fmt, ...) 740{ 741 static char buf[512]; 742 va_list ap; 743 744 va_start(ap, fmt); 745 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 746 error_message = buf; 747 va_end(ap); 748} 749 750/* 751 * Return a dynamically-allocated copy of the current error message, if any. 752 */ 753static char * 754errmsg_save(void) 755{ 756 return error_message == NULL ? NULL : xstrdup(error_message); 757} 758 759/* 760 * Restore the current error message from a copy which was previously saved 761 * by errmsg_save(). The copy is freed. 762 */ 763static void 764errmsg_restore(char *saved_msg) 765{ 766 if (saved_msg == NULL) 767 error_message = NULL; 768 else { 769 _rtld_error("%s", saved_msg); 770 free(saved_msg); 771 } 772} 773 774static const char * 775basename(const char *name) 776{ 777 const char *p = strrchr(name, '/'); 778 return p != NULL ? p + 1 : name; 779} 780 781static struct utsname uts; 782 783static char * 784origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 785 const char *subst, bool may_free) 786{ 787 char *p, *p1, *res, *resp; 788 int subst_len, kw_len, subst_count, old_len, new_len; 789 790 kw_len = strlen(kw); 791 792 /* 793 * First, count the number of the keyword occurences, to 794 * preallocate the final string. 795 */ 796 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 797 p1 = strstr(p, kw); 798 if (p1 == NULL) 799 break; 800 } 801 802 /* 803 * If the keyword is not found, just return. 804 * 805 * Return non-substituted string if resolution failed. We 806 * cannot do anything more reasonable, the failure mode of the 807 * caller is unresolved library anyway. 808 */ 809 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 810 return (may_free ? real : xstrdup(real)); 811 if (obj != NULL) 812 subst = obj->origin_path; 813 814 /* 815 * There is indeed something to substitute. Calculate the 816 * length of the resulting string, and allocate it. 817 */ 818 subst_len = strlen(subst); 819 old_len = strlen(real); 820 new_len = old_len + (subst_len - kw_len) * subst_count; 821 res = xmalloc(new_len + 1); 822 823 /* 824 * Now, execute the substitution loop. 825 */ 826 for (p = real, resp = res, *resp = '\0';;) { 827 p1 = strstr(p, kw); 828 if (p1 != NULL) { 829 /* Copy the prefix before keyword. */ 830 memcpy(resp, p, p1 - p); 831 resp += p1 - p; 832 /* Keyword replacement. */ 833 memcpy(resp, subst, subst_len); 834 resp += subst_len; 835 *resp = '\0'; 836 p = p1 + kw_len; 837 } else 838 break; 839 } 840 841 /* Copy to the end of string and finish. */ 842 strcat(resp, p); 843 if (may_free) 844 free(real); 845 return (res); 846} 847 848static char * 849origin_subst(Obj_Entry *obj, char *real) 850{ 851 char *res1, *res2, *res3, *res4; 852 853 if (obj == NULL || !trust) 854 return (xstrdup(real)); 855 if (uts.sysname[0] == '\0') { 856 if (uname(&uts) != 0) { 857 _rtld_error("utsname failed: %d", errno); 858 return (NULL); 859 } 860 } 861 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 862 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 863 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 864 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 865 return (res4); 866} 867 868void 869rtld_die(void) 870{ 871 const char *msg = dlerror(); 872 873 if (msg == NULL) 874 msg = "Fatal error"; 875 rtld_fdputstr(STDERR_FILENO, msg); 876 rtld_fdputchar(STDERR_FILENO, '\n'); 877 _exit(1); 878} 879 880/* 881 * Process a shared object's DYNAMIC section, and save the important 882 * information in its Obj_Entry structure. 883 */ 884static void 885digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 886 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 887{ 888 const Elf_Dyn *dynp; 889 Needed_Entry **needed_tail = &obj->needed; 890 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 891 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 892 const Elf_Hashelt *hashtab; 893 const Elf32_Word *hashval; 894 Elf32_Word bkt, nmaskwords; 895 int bloom_size32; 896 int plttype = DT_REL; 897 898 *dyn_rpath = NULL; 899 *dyn_soname = NULL; 900 *dyn_runpath = NULL; 901 902 obj->bind_now = false; 903 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 904 switch (dynp->d_tag) { 905 906 case DT_REL: 907 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 908 break; 909 910 case DT_RELSZ: 911 obj->relsize = dynp->d_un.d_val; 912 break; 913 914 case DT_RELENT: 915 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 916 break; 917 918 case DT_JMPREL: 919 obj->pltrel = (const Elf_Rel *) 920 (obj->relocbase + dynp->d_un.d_ptr); 921 break; 922 923 case DT_PLTRELSZ: 924 obj->pltrelsize = dynp->d_un.d_val; 925 break; 926 927 case DT_RELA: 928 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 929 break; 930 931 case DT_RELASZ: 932 obj->relasize = dynp->d_un.d_val; 933 break; 934 935 case DT_RELAENT: 936 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 937 break; 938 939 case DT_PLTREL: 940 plttype = dynp->d_un.d_val; 941 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 942 break; 943 944 case DT_SYMTAB: 945 obj->symtab = (const Elf_Sym *) 946 (obj->relocbase + dynp->d_un.d_ptr); 947 break; 948 949 case DT_SYMENT: 950 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 951 break; 952 953 case DT_STRTAB: 954 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 955 break; 956 957 case DT_STRSZ: 958 obj->strsize = dynp->d_un.d_val; 959 break; 960 961 case DT_VERNEED: 962 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 963 dynp->d_un.d_val); 964 break; 965 966 case DT_VERNEEDNUM: 967 obj->verneednum = dynp->d_un.d_val; 968 break; 969 970 case DT_VERDEF: 971 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 972 dynp->d_un.d_val); 973 break; 974 975 case DT_VERDEFNUM: 976 obj->verdefnum = dynp->d_un.d_val; 977 break; 978 979 case DT_VERSYM: 980 obj->versyms = (const Elf_Versym *)(obj->relocbase + 981 dynp->d_un.d_val); 982 break; 983 984 case DT_HASH: 985 { 986 hashtab = (const Elf_Hashelt *)(obj->relocbase + 987 dynp->d_un.d_ptr); 988 obj->nbuckets = hashtab[0]; 989 obj->nchains = hashtab[1]; 990 obj->buckets = hashtab + 2; 991 obj->chains = obj->buckets + obj->nbuckets; 992 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 993 obj->buckets != NULL; 994 } 995 break; 996 997 case DT_GNU_HASH: 998 { 999 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1000 dynp->d_un.d_ptr); 1001 obj->nbuckets_gnu = hashtab[0]; 1002 obj->symndx_gnu = hashtab[1]; 1003 nmaskwords = hashtab[2]; 1004 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1005 obj->maskwords_bm_gnu = nmaskwords - 1; 1006 obj->shift2_gnu = hashtab[3]; 1007 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1008 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1009 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1010 obj->symndx_gnu; 1011 /* Number of bitmask words is required to be power of 2 */ 1012 obj->valid_hash_gnu = powerof2(nmaskwords) && 1013 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1014 } 1015 break; 1016 1017 case DT_NEEDED: 1018 if (!obj->rtld) { 1019 Needed_Entry *nep = NEW(Needed_Entry); 1020 nep->name = dynp->d_un.d_val; 1021 nep->obj = NULL; 1022 nep->next = NULL; 1023 1024 *needed_tail = nep; 1025 needed_tail = &nep->next; 1026 } 1027 break; 1028 1029 case DT_FILTER: 1030 if (!obj->rtld) { 1031 Needed_Entry *nep = NEW(Needed_Entry); 1032 nep->name = dynp->d_un.d_val; 1033 nep->obj = NULL; 1034 nep->next = NULL; 1035 1036 *needed_filtees_tail = nep; 1037 needed_filtees_tail = &nep->next; 1038 } 1039 break; 1040 1041 case DT_AUXILIARY: 1042 if (!obj->rtld) { 1043 Needed_Entry *nep = NEW(Needed_Entry); 1044 nep->name = dynp->d_un.d_val; 1045 nep->obj = NULL; 1046 nep->next = NULL; 1047 1048 *needed_aux_filtees_tail = nep; 1049 needed_aux_filtees_tail = &nep->next; 1050 } 1051 break; 1052 1053 case DT_PLTGOT: 1054 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1055 break; 1056 1057 case DT_TEXTREL: 1058 obj->textrel = true; 1059 break; 1060 1061 case DT_SYMBOLIC: 1062 obj->symbolic = true; 1063 break; 1064 1065 case DT_RPATH: 1066 /* 1067 * We have to wait until later to process this, because we 1068 * might not have gotten the address of the string table yet. 1069 */ 1070 *dyn_rpath = dynp; 1071 break; 1072 1073 case DT_SONAME: 1074 *dyn_soname = dynp; 1075 break; 1076 1077 case DT_RUNPATH: 1078 *dyn_runpath = dynp; 1079 break; 1080 1081 case DT_INIT: 1082 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1083 break; 1084 1085 case DT_PREINIT_ARRAY: 1086 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1087 break; 1088 1089 case DT_PREINIT_ARRAYSZ: 1090 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1091 break; 1092 1093 case DT_INIT_ARRAY: 1094 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1095 break; 1096 1097 case DT_INIT_ARRAYSZ: 1098 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1099 break; 1100 1101 case DT_FINI: 1102 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1103 break; 1104 1105 case DT_FINI_ARRAY: 1106 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1107 break; 1108 1109 case DT_FINI_ARRAYSZ: 1110 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1111 break; 1112 1113 /* 1114 * Don't process DT_DEBUG on MIPS as the dynamic section 1115 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1116 */ 1117 1118#ifndef __mips__ 1119 case DT_DEBUG: 1120 /* XXX - not implemented yet */ 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 for (obj = obj_list; obj != NULL; obj = obj->next) 1380 if (obj == (Obj_Entry *) handle) 1381 break; 1382 1383 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1384 _rtld_error("Invalid shared object handle %p", handle); 1385 return NULL; 1386 } 1387 return obj; 1388} 1389 1390/* 1391 * If the given object is already in the donelist, return true. Otherwise 1392 * add the object to the list and return false. 1393 */ 1394static bool 1395donelist_check(DoneList *dlp, const Obj_Entry *obj) 1396{ 1397 unsigned int i; 1398 1399 for (i = 0; i < dlp->num_used; i++) 1400 if (dlp->objs[i] == obj) 1401 return true; 1402 /* 1403 * Our donelist allocation should always be sufficient. But if 1404 * our threads locking isn't working properly, more shared objects 1405 * could have been loaded since we allocated the list. That should 1406 * never happen, but we'll handle it properly just in case it does. 1407 */ 1408 if (dlp->num_used < dlp->num_alloc) 1409 dlp->objs[dlp->num_used++] = obj; 1410 return false; 1411} 1412 1413/* 1414 * Hash function for symbol table lookup. Don't even think about changing 1415 * this. It is specified by the System V ABI. 1416 */ 1417unsigned long 1418elf_hash(const char *name) 1419{ 1420 const unsigned char *p = (const unsigned char *) name; 1421 unsigned long h = 0; 1422 unsigned long g; 1423 1424 while (*p != '\0') { 1425 h = (h << 4) + *p++; 1426 if ((g = h & 0xf0000000) != 0) 1427 h ^= g >> 24; 1428 h &= ~g; 1429 } 1430 return h; 1431} 1432 1433/* 1434 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1435 * unsigned in case it's implemented with a wider type. 1436 */ 1437static uint32_t 1438gnu_hash(const char *s) 1439{ 1440 uint32_t h; 1441 unsigned char c; 1442 1443 h = 5381; 1444 for (c = *s; c != '\0'; c = *++s) 1445 h = h * 33 + c; 1446 return (h & 0xffffffff); 1447} 1448 1449/* 1450 * Find the library with the given name, and return its full pathname. 1451 * The returned string is dynamically allocated. Generates an error 1452 * message and returns NULL if the library cannot be found. 1453 * 1454 * If the second argument is non-NULL, then it refers to an already- 1455 * loaded shared object, whose library search path will be searched. 1456 * 1457 * The search order is: 1458 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1459 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1460 * LD_LIBRARY_PATH 1461 * DT_RUNPATH in the referencing file 1462 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1463 * from list) 1464 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1465 * 1466 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1467 */ 1468static char * 1469find_library(const char *xname, const Obj_Entry *refobj) 1470{ 1471 char *pathname; 1472 char *name; 1473 bool nodeflib, objgiven; 1474 1475 objgiven = refobj != NULL; 1476 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1477 if (xname[0] != '/' && !trust) { 1478 _rtld_error("Absolute pathname required for shared object \"%s\"", 1479 xname); 1480 return NULL; 1481 } 1482 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1483 __DECONST(char *, xname))); 1484 } 1485 1486 if (libmap_disable || !objgiven || 1487 (name = lm_find(refobj->path, xname)) == NULL) 1488 name = (char *)xname; 1489 1490 dbg(" Searching for \"%s\"", name); 1491 1492 /* 1493 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1494 * back to pre-conforming behaviour if user requested so with 1495 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1496 * nodeflib. 1497 */ 1498 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1499 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1500 (refobj != NULL && 1501 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1502 (pathname = search_library_path(name, gethints(false))) != NULL || 1503 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1504 return (pathname); 1505 } else { 1506 nodeflib = objgiven ? refobj->z_nodeflib : false; 1507 if ((objgiven && 1508 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1509 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1510 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1511 (pathname = search_library_path(name, ld_library_path)) != NULL || 1512 (objgiven && 1513 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1514 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1515 (objgiven && !nodeflib && 1516 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1517 return (pathname); 1518 } 1519 1520 if (objgiven && refobj->path != NULL) { 1521 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1522 name, basename(refobj->path)); 1523 } else { 1524 _rtld_error("Shared object \"%s\" not found", name); 1525 } 1526 return NULL; 1527} 1528 1529/* 1530 * Given a symbol number in a referencing object, find the corresponding 1531 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1532 * no definition was found. Returns a pointer to the Obj_Entry of the 1533 * defining object via the reference parameter DEFOBJ_OUT. 1534 */ 1535const Elf_Sym * 1536find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1537 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1538 RtldLockState *lockstate) 1539{ 1540 const Elf_Sym *ref; 1541 const Elf_Sym *def; 1542 const Obj_Entry *defobj; 1543 SymLook req; 1544 const char *name; 1545 int res; 1546 1547 /* 1548 * If we have already found this symbol, get the information from 1549 * the cache. 1550 */ 1551 if (symnum >= refobj->dynsymcount) 1552 return NULL; /* Bad object */ 1553 if (cache != NULL && cache[symnum].sym != NULL) { 1554 *defobj_out = cache[symnum].obj; 1555 return cache[symnum].sym; 1556 } 1557 1558 ref = refobj->symtab + symnum; 1559 name = refobj->strtab + ref->st_name; 1560 def = NULL; 1561 defobj = NULL; 1562 1563 /* 1564 * We don't have to do a full scale lookup if the symbol is local. 1565 * We know it will bind to the instance in this load module; to 1566 * which we already have a pointer (ie ref). By not doing a lookup, 1567 * we not only improve performance, but it also avoids unresolvable 1568 * symbols when local symbols are not in the hash table. This has 1569 * been seen with the ia64 toolchain. 1570 */ 1571 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1572 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1573 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1574 symnum); 1575 } 1576 symlook_init(&req, name); 1577 req.flags = flags; 1578 req.ventry = fetch_ventry(refobj, symnum); 1579 req.lockstate = lockstate; 1580 res = symlook_default(&req, refobj); 1581 if (res == 0) { 1582 def = req.sym_out; 1583 defobj = req.defobj_out; 1584 } 1585 } else { 1586 def = ref; 1587 defobj = refobj; 1588 } 1589 1590 /* 1591 * If we found no definition and the reference is weak, treat the 1592 * symbol as having the value zero. 1593 */ 1594 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1595 def = &sym_zero; 1596 defobj = obj_main; 1597 } 1598 1599 if (def != NULL) { 1600 *defobj_out = defobj; 1601 /* Record the information in the cache to avoid subsequent lookups. */ 1602 if (cache != NULL) { 1603 cache[symnum].sym = def; 1604 cache[symnum].obj = defobj; 1605 } 1606 } else { 1607 if (refobj != &obj_rtld) 1608 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1609 } 1610 return def; 1611} 1612 1613/* 1614 * Return the search path from the ldconfig hints file, reading it if 1615 * necessary. If nostdlib is true, then the default search paths are 1616 * not added to result. 1617 * 1618 * Returns NULL if there are problems with the hints file, 1619 * or if the search path there is empty. 1620 */ 1621static const char * 1622gethints(bool nostdlib) 1623{ 1624 static char *hints, *filtered_path; 1625 struct elfhints_hdr hdr; 1626 struct fill_search_info_args sargs, hargs; 1627 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1628 struct dl_serpath *SLPpath, *hintpath; 1629 char *p; 1630 unsigned int SLPndx, hintndx, fndx, fcount; 1631 int fd; 1632 size_t flen; 1633 bool skip; 1634 1635 /* First call, read the hints file */ 1636 if (hints == NULL) { 1637 /* Keep from trying again in case the hints file is bad. */ 1638 hints = ""; 1639 1640 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1641 return (NULL); 1642 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1643 hdr.magic != ELFHINTS_MAGIC || 1644 hdr.version != 1) { 1645 close(fd); 1646 return (NULL); 1647 } 1648 p = xmalloc(hdr.dirlistlen + 1); 1649 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1650 read(fd, p, hdr.dirlistlen + 1) != 1651 (ssize_t)hdr.dirlistlen + 1) { 1652 free(p); 1653 close(fd); 1654 return (NULL); 1655 } 1656 hints = p; 1657 close(fd); 1658 } 1659 1660 /* 1661 * If caller agreed to receive list which includes the default 1662 * paths, we are done. Otherwise, if we still did not 1663 * calculated filtered result, do it now. 1664 */ 1665 if (!nostdlib) 1666 return (hints[0] != '\0' ? hints : NULL); 1667 if (filtered_path != NULL) 1668 goto filt_ret; 1669 1670 /* 1671 * Obtain the list of all configured search paths, and the 1672 * list of the default paths. 1673 * 1674 * First estimate the size of the results. 1675 */ 1676 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1677 smeta.dls_cnt = 0; 1678 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1679 hmeta.dls_cnt = 0; 1680 1681 sargs.request = RTLD_DI_SERINFOSIZE; 1682 sargs.serinfo = &smeta; 1683 hargs.request = RTLD_DI_SERINFOSIZE; 1684 hargs.serinfo = &hmeta; 1685 1686 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1687 path_enumerate(p, fill_search_info, &hargs); 1688 1689 SLPinfo = xmalloc(smeta.dls_size); 1690 hintinfo = xmalloc(hmeta.dls_size); 1691 1692 /* 1693 * Next fetch both sets of paths. 1694 */ 1695 sargs.request = RTLD_DI_SERINFO; 1696 sargs.serinfo = SLPinfo; 1697 sargs.serpath = &SLPinfo->dls_serpath[0]; 1698 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1699 1700 hargs.request = RTLD_DI_SERINFO; 1701 hargs.serinfo = hintinfo; 1702 hargs.serpath = &hintinfo->dls_serpath[0]; 1703 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1704 1705 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1706 path_enumerate(p, fill_search_info, &hargs); 1707 1708 /* 1709 * Now calculate the difference between two sets, by excluding 1710 * standard paths from the full set. 1711 */ 1712 fndx = 0; 1713 fcount = 0; 1714 filtered_path = xmalloc(hdr.dirlistlen + 1); 1715 hintpath = &hintinfo->dls_serpath[0]; 1716 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1717 skip = false; 1718 SLPpath = &SLPinfo->dls_serpath[0]; 1719 /* 1720 * Check each standard path against current. 1721 */ 1722 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1723 /* matched, skip the path */ 1724 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1725 skip = true; 1726 break; 1727 } 1728 } 1729 if (skip) 1730 continue; 1731 /* 1732 * Not matched against any standard path, add the path 1733 * to result. Separate consequtive paths with ':'. 1734 */ 1735 if (fcount > 0) { 1736 filtered_path[fndx] = ':'; 1737 fndx++; 1738 } 1739 fcount++; 1740 flen = strlen(hintpath->dls_name); 1741 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1742 fndx += flen; 1743 } 1744 filtered_path[fndx] = '\0'; 1745 1746 free(SLPinfo); 1747 free(hintinfo); 1748 1749filt_ret: 1750 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1751} 1752 1753static void 1754init_dag(Obj_Entry *root) 1755{ 1756 const Needed_Entry *needed; 1757 const Objlist_Entry *elm; 1758 DoneList donelist; 1759 1760 if (root->dag_inited) 1761 return; 1762 donelist_init(&donelist); 1763 1764 /* Root object belongs to own DAG. */ 1765 objlist_push_tail(&root->dldags, root); 1766 objlist_push_tail(&root->dagmembers, root); 1767 donelist_check(&donelist, root); 1768 1769 /* 1770 * Add dependencies of root object to DAG in breadth order 1771 * by exploiting the fact that each new object get added 1772 * to the tail of the dagmembers list. 1773 */ 1774 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1775 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1776 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1777 continue; 1778 objlist_push_tail(&needed->obj->dldags, root); 1779 objlist_push_tail(&root->dagmembers, needed->obj); 1780 } 1781 } 1782 root->dag_inited = true; 1783} 1784 1785static void 1786process_z(Obj_Entry *root) 1787{ 1788 const Objlist_Entry *elm; 1789 Obj_Entry *obj; 1790 1791 /* 1792 * Walk over object DAG and process every dependent object 1793 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1794 * to grow their own DAG. 1795 * 1796 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1797 * symlook_global() to work. 1798 * 1799 * For DF_1_NODELETE, the DAG should have its reference upped. 1800 */ 1801 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1802 obj = elm->obj; 1803 if (obj == NULL) 1804 continue; 1805 if (obj->z_nodelete && !obj->ref_nodel) { 1806 dbg("obj %s -z nodelete", obj->path); 1807 init_dag(obj); 1808 ref_dag(obj); 1809 obj->ref_nodel = true; 1810 } 1811 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1812 dbg("obj %s -z global", obj->path); 1813 objlist_push_tail(&list_global, obj); 1814 init_dag(obj); 1815 } 1816 } 1817} 1818/* 1819 * Initialize the dynamic linker. The argument is the address at which 1820 * the dynamic linker has been mapped into memory. The primary task of 1821 * this function is to relocate the dynamic linker. 1822 */ 1823static void 1824init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1825{ 1826 Obj_Entry objtmp; /* Temporary rtld object */ 1827 const Elf_Dyn *dyn_rpath; 1828 const Elf_Dyn *dyn_soname; 1829 const Elf_Dyn *dyn_runpath; 1830 1831#ifdef RTLD_INIT_PAGESIZES_EARLY 1832 /* The page size is required by the dynamic memory allocator. */ 1833 init_pagesizes(aux_info); 1834#endif 1835 1836 /* 1837 * Conjure up an Obj_Entry structure for the dynamic linker. 1838 * 1839 * The "path" member can't be initialized yet because string constants 1840 * cannot yet be accessed. Below we will set it correctly. 1841 */ 1842 memset(&objtmp, 0, sizeof(objtmp)); 1843 objtmp.path = NULL; 1844 objtmp.rtld = true; 1845 objtmp.mapbase = mapbase; 1846#ifdef PIC 1847 objtmp.relocbase = mapbase; 1848#endif 1849 if (RTLD_IS_DYNAMIC()) { 1850 objtmp.dynamic = rtld_dynamic(&objtmp); 1851 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1852 assert(objtmp.needed == NULL); 1853#if !defined(__mips__) 1854 /* MIPS has a bogus DT_TEXTREL. */ 1855 assert(!objtmp.textrel); 1856#endif 1857 1858 /* 1859 * Temporarily put the dynamic linker entry into the object list, so 1860 * that symbols can be found. 1861 */ 1862 1863 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1864 } 1865 1866 /* Initialize the object list. */ 1867 obj_tail = &obj_list; 1868 1869 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1870 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1871 1872#ifndef RTLD_INIT_PAGESIZES_EARLY 1873 /* The page size is required by the dynamic memory allocator. */ 1874 init_pagesizes(aux_info); 1875#endif 1876 1877 if (aux_info[AT_OSRELDATE] != NULL) 1878 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1879 1880 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1881 1882 /* Replace the path with a dynamically allocated copy. */ 1883 obj_rtld.path = xstrdup(PATH_RTLD); 1884 1885 r_debug.r_brk = r_debug_state; 1886 r_debug.r_state = RT_CONSISTENT; 1887} 1888 1889/* 1890 * Retrieve the array of supported page sizes. The kernel provides the page 1891 * sizes in increasing order. 1892 */ 1893static void 1894init_pagesizes(Elf_Auxinfo **aux_info) 1895{ 1896 static size_t psa[MAXPAGESIZES]; 1897 int mib[2]; 1898 size_t len, size; 1899 1900 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1901 NULL) { 1902 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1903 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1904 } else { 1905 len = 2; 1906 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1907 size = sizeof(psa); 1908 else { 1909 /* As a fallback, retrieve the base page size. */ 1910 size = sizeof(psa[0]); 1911 if (aux_info[AT_PAGESZ] != NULL) { 1912 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1913 goto psa_filled; 1914 } else { 1915 mib[0] = CTL_HW; 1916 mib[1] = HW_PAGESIZE; 1917 len = 2; 1918 } 1919 } 1920 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1921 _rtld_error("sysctl for hw.pagesize(s) failed"); 1922 rtld_die(); 1923 } 1924psa_filled: 1925 pagesizes = psa; 1926 } 1927 npagesizes = size / sizeof(pagesizes[0]); 1928 /* Discard any invalid entries at the end of the array. */ 1929 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1930 npagesizes--; 1931} 1932 1933/* 1934 * Add the init functions from a needed object list (and its recursive 1935 * needed objects) to "list". This is not used directly; it is a helper 1936 * function for initlist_add_objects(). The write lock must be held 1937 * when this function is called. 1938 */ 1939static void 1940initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1941{ 1942 /* Recursively process the successor needed objects. */ 1943 if (needed->next != NULL) 1944 initlist_add_neededs(needed->next, list); 1945 1946 /* Process the current needed object. */ 1947 if (needed->obj != NULL) 1948 initlist_add_objects(needed->obj, &needed->obj->next, list); 1949} 1950 1951/* 1952 * Scan all of the DAGs rooted in the range of objects from "obj" to 1953 * "tail" and add their init functions to "list". This recurses over 1954 * the DAGs and ensure the proper init ordering such that each object's 1955 * needed libraries are initialized before the object itself. At the 1956 * same time, this function adds the objects to the global finalization 1957 * list "list_fini" in the opposite order. The write lock must be 1958 * held when this function is called. 1959 */ 1960static void 1961initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1962{ 1963 1964 if (obj->init_scanned || obj->init_done) 1965 return; 1966 obj->init_scanned = true; 1967 1968 /* Recursively process the successor objects. */ 1969 if (&obj->next != tail) 1970 initlist_add_objects(obj->next, tail, list); 1971 1972 /* Recursively process the needed objects. */ 1973 if (obj->needed != NULL) 1974 initlist_add_neededs(obj->needed, list); 1975 if (obj->needed_filtees != NULL) 1976 initlist_add_neededs(obj->needed_filtees, list); 1977 if (obj->needed_aux_filtees != NULL) 1978 initlist_add_neededs(obj->needed_aux_filtees, list); 1979 1980 /* Add the object to the init list. */ 1981 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1982 obj->init_array != (Elf_Addr)NULL) 1983 objlist_push_tail(list, obj); 1984 1985 /* Add the object to the global fini list in the reverse order. */ 1986 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1987 && !obj->on_fini_list) { 1988 objlist_push_head(&list_fini, obj); 1989 obj->on_fini_list = true; 1990 } 1991} 1992 1993#ifndef FPTR_TARGET 1994#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1995#endif 1996 1997static void 1998free_needed_filtees(Needed_Entry *n) 1999{ 2000 Needed_Entry *needed, *needed1; 2001 2002 for (needed = n; needed != NULL; needed = needed->next) { 2003 if (needed->obj != NULL) { 2004 dlclose(needed->obj); 2005 needed->obj = NULL; 2006 } 2007 } 2008 for (needed = n; needed != NULL; needed = needed1) { 2009 needed1 = needed->next; 2010 free(needed); 2011 } 2012} 2013 2014static void 2015unload_filtees(Obj_Entry *obj) 2016{ 2017 2018 free_needed_filtees(obj->needed_filtees); 2019 obj->needed_filtees = NULL; 2020 free_needed_filtees(obj->needed_aux_filtees); 2021 obj->needed_aux_filtees = NULL; 2022 obj->filtees_loaded = false; 2023} 2024 2025static void 2026load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2027 RtldLockState *lockstate) 2028{ 2029 2030 for (; needed != NULL; needed = needed->next) { 2031 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2032 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2033 RTLD_LOCAL, lockstate); 2034 } 2035} 2036 2037static void 2038load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2039{ 2040 2041 lock_restart_for_upgrade(lockstate); 2042 if (!obj->filtees_loaded) { 2043 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2044 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2045 obj->filtees_loaded = true; 2046 } 2047} 2048 2049static int 2050process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2051{ 2052 Obj_Entry *obj1; 2053 2054 for (; needed != NULL; needed = needed->next) { 2055 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2056 flags & ~RTLD_LO_NOLOAD); 2057 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2058 return (-1); 2059 } 2060 return (0); 2061} 2062 2063/* 2064 * Given a shared object, traverse its list of needed objects, and load 2065 * each of them. Returns 0 on success. Generates an error message and 2066 * returns -1 on failure. 2067 */ 2068static int 2069load_needed_objects(Obj_Entry *first, int flags) 2070{ 2071 Obj_Entry *obj; 2072 2073 for (obj = first; obj != NULL; obj = obj->next) { 2074 if (process_needed(obj, obj->needed, flags) == -1) 2075 return (-1); 2076 } 2077 return (0); 2078} 2079 2080static int 2081load_preload_objects(void) 2082{ 2083 char *p = ld_preload; 2084 Obj_Entry *obj; 2085 static const char delim[] = " \t:;"; 2086 2087 if (p == NULL) 2088 return 0; 2089 2090 p += strspn(p, delim); 2091 while (*p != '\0') { 2092 size_t len = strcspn(p, delim); 2093 char savech; 2094 2095 savech = p[len]; 2096 p[len] = '\0'; 2097 obj = load_object(p, -1, NULL, 0); 2098 if (obj == NULL) 2099 return -1; /* XXX - cleanup */ 2100 obj->z_interpose = true; 2101 p[len] = savech; 2102 p += len; 2103 p += strspn(p, delim); 2104 } 2105 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2106 return 0; 2107} 2108 2109static const char * 2110printable_path(const char *path) 2111{ 2112 2113 return (path == NULL ? "<unknown>" : path); 2114} 2115 2116/* 2117 * Load a shared object into memory, if it is not already loaded. The 2118 * object may be specified by name or by user-supplied file descriptor 2119 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2120 * duplicate is. 2121 * 2122 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2123 * on failure. 2124 */ 2125static Obj_Entry * 2126load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2127{ 2128 Obj_Entry *obj; 2129 int fd; 2130 struct stat sb; 2131 char *path; 2132 2133 if (name != NULL) { 2134 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2135 if (object_match_name(obj, name)) 2136 return (obj); 2137 } 2138 2139 path = find_library(name, refobj); 2140 if (path == NULL) 2141 return (NULL); 2142 } else 2143 path = NULL; 2144 2145 /* 2146 * If we didn't find a match by pathname, or the name is not 2147 * supplied, open the file and check again by device and inode. 2148 * This avoids false mismatches caused by multiple links or ".." 2149 * in pathnames. 2150 * 2151 * To avoid a race, we open the file and use fstat() rather than 2152 * using stat(). 2153 */ 2154 fd = -1; 2155 if (fd_u == -1) { 2156 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2157 _rtld_error("Cannot open \"%s\"", path); 2158 free(path); 2159 return (NULL); 2160 } 2161 } else { 2162 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2163 if (fd == -1) { 2164 _rtld_error("Cannot dup fd"); 2165 free(path); 2166 return (NULL); 2167 } 2168 } 2169 if (fstat(fd, &sb) == -1) { 2170 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2171 close(fd); 2172 free(path); 2173 return NULL; 2174 } 2175 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2176 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2177 break; 2178 if (obj != NULL && name != NULL) { 2179 object_add_name(obj, name); 2180 free(path); 2181 close(fd); 2182 return obj; 2183 } 2184 if (flags & RTLD_LO_NOLOAD) { 2185 free(path); 2186 close(fd); 2187 return (NULL); 2188 } 2189 2190 /* First use of this object, so we must map it in */ 2191 obj = do_load_object(fd, name, path, &sb, flags); 2192 if (obj == NULL) 2193 free(path); 2194 close(fd); 2195 2196 return obj; 2197} 2198 2199static Obj_Entry * 2200do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2201 int flags) 2202{ 2203 Obj_Entry *obj; 2204 struct statfs fs; 2205 2206 /* 2207 * but first, make sure that environment variables haven't been 2208 * used to circumvent the noexec flag on a filesystem. 2209 */ 2210 if (dangerous_ld_env) { 2211 if (fstatfs(fd, &fs) != 0) { 2212 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2213 return NULL; 2214 } 2215 if (fs.f_flags & MNT_NOEXEC) { 2216 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2217 return NULL; 2218 } 2219 } 2220 dbg("loading \"%s\"", printable_path(path)); 2221 obj = map_object(fd, printable_path(path), sbp); 2222 if (obj == NULL) 2223 return NULL; 2224 2225 /* 2226 * If DT_SONAME is present in the object, digest_dynamic2 already 2227 * added it to the object names. 2228 */ 2229 if (name != NULL) 2230 object_add_name(obj, name); 2231 obj->path = path; 2232 digest_dynamic(obj, 0); 2233 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2234 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2235 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2236 RTLD_LO_DLOPEN) { 2237 dbg("refusing to load non-loadable \"%s\"", obj->path); 2238 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2239 munmap(obj->mapbase, obj->mapsize); 2240 obj_free(obj); 2241 return (NULL); 2242 } 2243 2244 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2245 *obj_tail = obj; 2246 obj_tail = &obj->next; 2247 obj_count++; 2248 obj_loads++; 2249 linkmap_add(obj); /* for GDB & dlinfo() */ 2250 max_stack_flags |= obj->stack_flags; 2251 2252 dbg(" %p .. %p: %s", obj->mapbase, 2253 obj->mapbase + obj->mapsize - 1, obj->path); 2254 if (obj->textrel) 2255 dbg(" WARNING: %s has impure text", obj->path); 2256 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2257 obj->path); 2258 2259 return obj; 2260} 2261 2262static Obj_Entry * 2263obj_from_addr(const void *addr) 2264{ 2265 Obj_Entry *obj; 2266 2267 for (obj = obj_list; obj != NULL; obj = obj->next) { 2268 if (addr < (void *) obj->mapbase) 2269 continue; 2270 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2271 return obj; 2272 } 2273 return NULL; 2274} 2275 2276static void 2277preinit_main(void) 2278{ 2279 Elf_Addr *preinit_addr; 2280 int index; 2281 2282 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2283 if (preinit_addr == NULL) 2284 return; 2285 2286 for (index = 0; index < obj_main->preinit_array_num; index++) { 2287 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2288 dbg("calling preinit function for %s at %p", obj_main->path, 2289 (void *)preinit_addr[index]); 2290 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2291 0, 0, obj_main->path); 2292 call_init_pointer(obj_main, preinit_addr[index]); 2293 } 2294 } 2295} 2296 2297/* 2298 * Call the finalization functions for each of the objects in "list" 2299 * belonging to the DAG of "root" and referenced once. If NULL "root" 2300 * is specified, every finalization function will be called regardless 2301 * of the reference count and the list elements won't be freed. All of 2302 * the objects are expected to have non-NULL fini functions. 2303 */ 2304static void 2305objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2306{ 2307 Objlist_Entry *elm; 2308 char *saved_msg; 2309 Elf_Addr *fini_addr; 2310 int index; 2311 2312 assert(root == NULL || root->refcount == 1); 2313 2314 /* 2315 * Preserve the current error message since a fini function might 2316 * call into the dynamic linker and overwrite it. 2317 */ 2318 saved_msg = errmsg_save(); 2319 do { 2320 STAILQ_FOREACH(elm, list, link) { 2321 if (root != NULL && (elm->obj->refcount != 1 || 2322 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2323 continue; 2324 /* Remove object from fini list to prevent recursive invocation. */ 2325 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2326 /* 2327 * XXX: If a dlopen() call references an object while the 2328 * fini function is in progress, we might end up trying to 2329 * unload the referenced object in dlclose() or the object 2330 * won't be unloaded although its fini function has been 2331 * called. 2332 */ 2333 lock_release(rtld_bind_lock, lockstate); 2334 2335 /* 2336 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2337 * When this happens, DT_FINI_ARRAY is processed first. 2338 */ 2339 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2340 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2341 for (index = elm->obj->fini_array_num - 1; index >= 0; 2342 index--) { 2343 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2344 dbg("calling fini function for %s at %p", 2345 elm->obj->path, (void *)fini_addr[index]); 2346 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2347 (void *)fini_addr[index], 0, 0, elm->obj->path); 2348 call_initfini_pointer(elm->obj, fini_addr[index]); 2349 } 2350 } 2351 } 2352 if (elm->obj->fini != (Elf_Addr)NULL) { 2353 dbg("calling fini function for %s at %p", elm->obj->path, 2354 (void *)elm->obj->fini); 2355 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2356 0, 0, elm->obj->path); 2357 call_initfini_pointer(elm->obj, elm->obj->fini); 2358 } 2359 wlock_acquire(rtld_bind_lock, lockstate); 2360 /* No need to free anything if process is going down. */ 2361 if (root != NULL) 2362 free(elm); 2363 /* 2364 * We must restart the list traversal after every fini call 2365 * because a dlclose() call from the fini function or from 2366 * another thread might have modified the reference counts. 2367 */ 2368 break; 2369 } 2370 } while (elm != NULL); 2371 errmsg_restore(saved_msg); 2372} 2373 2374/* 2375 * Call the initialization functions for each of the objects in 2376 * "list". All of the objects are expected to have non-NULL init 2377 * functions. 2378 */ 2379static void 2380objlist_call_init(Objlist *list, RtldLockState *lockstate) 2381{ 2382 Objlist_Entry *elm; 2383 Obj_Entry *obj; 2384 char *saved_msg; 2385 Elf_Addr *init_addr; 2386 int index; 2387 2388 /* 2389 * Clean init_scanned flag so that objects can be rechecked and 2390 * possibly initialized earlier if any of vectors called below 2391 * cause the change by using dlopen. 2392 */ 2393 for (obj = obj_list; obj != NULL; obj = obj->next) 2394 obj->init_scanned = false; 2395 2396 /* 2397 * Preserve the current error message since an init function might 2398 * call into the dynamic linker and overwrite it. 2399 */ 2400 saved_msg = errmsg_save(); 2401 STAILQ_FOREACH(elm, list, link) { 2402 if (elm->obj->init_done) /* Initialized early. */ 2403 continue; 2404 /* 2405 * Race: other thread might try to use this object before current 2406 * one completes the initilization. Not much can be done here 2407 * without better locking. 2408 */ 2409 elm->obj->init_done = true; 2410 lock_release(rtld_bind_lock, lockstate); 2411 2412 /* 2413 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2414 * When this happens, DT_INIT is processed first. 2415 */ 2416 if (elm->obj->init != (Elf_Addr)NULL) { 2417 dbg("calling init function for %s at %p", elm->obj->path, 2418 (void *)elm->obj->init); 2419 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2420 0, 0, elm->obj->path); 2421 call_initfini_pointer(elm->obj, elm->obj->init); 2422 } 2423 init_addr = (Elf_Addr *)elm->obj->init_array; 2424 if (init_addr != NULL) { 2425 for (index = 0; index < elm->obj->init_array_num; index++) { 2426 if (init_addr[index] != 0 && init_addr[index] != 1) { 2427 dbg("calling init function for %s at %p", elm->obj->path, 2428 (void *)init_addr[index]); 2429 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2430 (void *)init_addr[index], 0, 0, elm->obj->path); 2431 call_init_pointer(elm->obj, init_addr[index]); 2432 } 2433 } 2434 } 2435 wlock_acquire(rtld_bind_lock, lockstate); 2436 } 2437 errmsg_restore(saved_msg); 2438} 2439 2440static void 2441objlist_clear(Objlist *list) 2442{ 2443 Objlist_Entry *elm; 2444 2445 while (!STAILQ_EMPTY(list)) { 2446 elm = STAILQ_FIRST(list); 2447 STAILQ_REMOVE_HEAD(list, link); 2448 free(elm); 2449 } 2450} 2451 2452static Objlist_Entry * 2453objlist_find(Objlist *list, const Obj_Entry *obj) 2454{ 2455 Objlist_Entry *elm; 2456 2457 STAILQ_FOREACH(elm, list, link) 2458 if (elm->obj == obj) 2459 return elm; 2460 return NULL; 2461} 2462 2463static void 2464objlist_init(Objlist *list) 2465{ 2466 STAILQ_INIT(list); 2467} 2468 2469static void 2470objlist_push_head(Objlist *list, Obj_Entry *obj) 2471{ 2472 Objlist_Entry *elm; 2473 2474 elm = NEW(Objlist_Entry); 2475 elm->obj = obj; 2476 STAILQ_INSERT_HEAD(list, elm, link); 2477} 2478 2479static void 2480objlist_push_tail(Objlist *list, Obj_Entry *obj) 2481{ 2482 Objlist_Entry *elm; 2483 2484 elm = NEW(Objlist_Entry); 2485 elm->obj = obj; 2486 STAILQ_INSERT_TAIL(list, elm, link); 2487} 2488 2489static void 2490objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2491{ 2492 Objlist_Entry *elm, *listelm; 2493 2494 STAILQ_FOREACH(listelm, list, link) { 2495 if (listelm->obj == listobj) 2496 break; 2497 } 2498 elm = NEW(Objlist_Entry); 2499 elm->obj = obj; 2500 if (listelm != NULL) 2501 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2502 else 2503 STAILQ_INSERT_TAIL(list, elm, link); 2504} 2505 2506static void 2507objlist_remove(Objlist *list, Obj_Entry *obj) 2508{ 2509 Objlist_Entry *elm; 2510 2511 if ((elm = objlist_find(list, obj)) != NULL) { 2512 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2513 free(elm); 2514 } 2515} 2516 2517/* 2518 * Relocate dag rooted in the specified object. 2519 * Returns 0 on success, or -1 on failure. 2520 */ 2521 2522static int 2523relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2524 int flags, RtldLockState *lockstate) 2525{ 2526 Objlist_Entry *elm; 2527 int error; 2528 2529 error = 0; 2530 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2531 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2532 lockstate); 2533 if (error == -1) 2534 break; 2535 } 2536 return (error); 2537} 2538 2539/* 2540 * Relocate single object. 2541 * Returns 0 on success, or -1 on failure. 2542 */ 2543static int 2544relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2545 int flags, RtldLockState *lockstate) 2546{ 2547 2548 if (obj->relocated) 2549 return (0); 2550 obj->relocated = true; 2551 if (obj != rtldobj) 2552 dbg("relocating \"%s\"", obj->path); 2553 2554 if (obj->symtab == NULL || obj->strtab == NULL || 2555 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2556 _rtld_error("%s: Shared object has no run-time symbol table", 2557 obj->path); 2558 return (-1); 2559 } 2560 2561 if (obj->textrel) { 2562 /* There are relocations to the write-protected text segment. */ 2563 if (mprotect(obj->mapbase, obj->textsize, 2564 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2565 _rtld_error("%s: Cannot write-enable text segment: %s", 2566 obj->path, rtld_strerror(errno)); 2567 return (-1); 2568 } 2569 } 2570 2571 /* Process the non-PLT non-IFUNC relocations. */ 2572 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2573 return (-1); 2574 2575 if (obj->textrel) { /* Re-protected the text segment. */ 2576 if (mprotect(obj->mapbase, obj->textsize, 2577 PROT_READ|PROT_EXEC) == -1) { 2578 _rtld_error("%s: Cannot write-protect text segment: %s", 2579 obj->path, rtld_strerror(errno)); 2580 return (-1); 2581 } 2582 } 2583 2584 /* Set the special PLT or GOT entries. */ 2585 init_pltgot(obj); 2586 2587 /* Process the PLT relocations. */ 2588 if (reloc_plt(obj) == -1) 2589 return (-1); 2590 /* Relocate the jump slots if we are doing immediate binding. */ 2591 if (obj->bind_now || bind_now) 2592 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2593 return (-1); 2594 2595 /* 2596 * Process the non-PLT IFUNC relocations. The relocations are 2597 * processed in two phases, because IFUNC resolvers may 2598 * reference other symbols, which must be readily processed 2599 * before resolvers are called. 2600 */ 2601 if (obj->non_plt_gnu_ifunc && 2602 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2603 return (-1); 2604 2605 if (obj->relro_size > 0) { 2606 if (mprotect(obj->relro_page, obj->relro_size, 2607 PROT_READ) == -1) { 2608 _rtld_error("%s: Cannot enforce relro protection: %s", 2609 obj->path, rtld_strerror(errno)); 2610 return (-1); 2611 } 2612 } 2613 2614 /* 2615 * Set up the magic number and version in the Obj_Entry. These 2616 * were checked in the crt1.o from the original ElfKit, so we 2617 * set them for backward compatibility. 2618 */ 2619 obj->magic = RTLD_MAGIC; 2620 obj->version = RTLD_VERSION; 2621 2622 return (0); 2623} 2624 2625/* 2626 * Relocate newly-loaded shared objects. The argument is a pointer to 2627 * the Obj_Entry for the first such object. All objects from the first 2628 * to the end of the list of objects are relocated. Returns 0 on success, 2629 * or -1 on failure. 2630 */ 2631static int 2632relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2633 int flags, RtldLockState *lockstate) 2634{ 2635 Obj_Entry *obj; 2636 int error; 2637 2638 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2639 error = relocate_object(obj, bind_now, rtldobj, flags, 2640 lockstate); 2641 if (error == -1) 2642 break; 2643 } 2644 return (error); 2645} 2646 2647/* 2648 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2649 * referencing STT_GNU_IFUNC symbols is postponed till the other 2650 * relocations are done. The indirect functions specified as 2651 * ifunc are allowed to call other symbols, so we need to have 2652 * objects relocated before asking for resolution from indirects. 2653 * 2654 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2655 * instead of the usual lazy handling of PLT slots. It is 2656 * consistent with how GNU does it. 2657 */ 2658static int 2659resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2660 RtldLockState *lockstate) 2661{ 2662 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2663 return (-1); 2664 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2665 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2666 return (-1); 2667 return (0); 2668} 2669 2670static int 2671resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2672 RtldLockState *lockstate) 2673{ 2674 Obj_Entry *obj; 2675 2676 for (obj = first; obj != NULL; obj = obj->next) { 2677 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2678 return (-1); 2679 } 2680 return (0); 2681} 2682 2683static int 2684initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2685 RtldLockState *lockstate) 2686{ 2687 Objlist_Entry *elm; 2688 2689 STAILQ_FOREACH(elm, list, link) { 2690 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2691 lockstate) == -1) 2692 return (-1); 2693 } 2694 return (0); 2695} 2696 2697/* 2698 * Cleanup procedure. It will be called (by the atexit mechanism) just 2699 * before the process exits. 2700 */ 2701static void 2702rtld_exit(void) 2703{ 2704 RtldLockState lockstate; 2705 2706 wlock_acquire(rtld_bind_lock, &lockstate); 2707 dbg("rtld_exit()"); 2708 objlist_call_fini(&list_fini, NULL, &lockstate); 2709 /* No need to remove the items from the list, since we are exiting. */ 2710 if (!libmap_disable) 2711 lm_fini(); 2712 lock_release(rtld_bind_lock, &lockstate); 2713} 2714 2715/* 2716 * Iterate over a search path, translate each element, and invoke the 2717 * callback on the result. 2718 */ 2719static void * 2720path_enumerate(const char *path, path_enum_proc callback, void *arg) 2721{ 2722 const char *trans; 2723 if (path == NULL) 2724 return (NULL); 2725 2726 path += strspn(path, ":;"); 2727 while (*path != '\0') { 2728 size_t len; 2729 char *res; 2730 2731 len = strcspn(path, ":;"); 2732 trans = lm_findn(NULL, path, len); 2733 if (trans) 2734 res = callback(trans, strlen(trans), arg); 2735 else 2736 res = callback(path, len, arg); 2737 2738 if (res != NULL) 2739 return (res); 2740 2741 path += len; 2742 path += strspn(path, ":;"); 2743 } 2744 2745 return (NULL); 2746} 2747 2748struct try_library_args { 2749 const char *name; 2750 size_t namelen; 2751 char *buffer; 2752 size_t buflen; 2753}; 2754 2755static void * 2756try_library_path(const char *dir, size_t dirlen, void *param) 2757{ 2758 struct try_library_args *arg; 2759 2760 arg = param; 2761 if (*dir == '/' || trust) { 2762 char *pathname; 2763 2764 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2765 return (NULL); 2766 2767 pathname = arg->buffer; 2768 strncpy(pathname, dir, dirlen); 2769 pathname[dirlen] = '/'; 2770 strcpy(pathname + dirlen + 1, arg->name); 2771 2772 dbg(" Trying \"%s\"", pathname); 2773 if (access(pathname, F_OK) == 0) { /* We found it */ 2774 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2775 strcpy(pathname, arg->buffer); 2776 return (pathname); 2777 } 2778 } 2779 return (NULL); 2780} 2781 2782static char * 2783search_library_path(const char *name, const char *path) 2784{ 2785 char *p; 2786 struct try_library_args arg; 2787 2788 if (path == NULL) 2789 return NULL; 2790 2791 arg.name = name; 2792 arg.namelen = strlen(name); 2793 arg.buffer = xmalloc(PATH_MAX); 2794 arg.buflen = PATH_MAX; 2795 2796 p = path_enumerate(path, try_library_path, &arg); 2797 2798 free(arg.buffer); 2799 2800 return (p); 2801} 2802 2803int 2804dlclose(void *handle) 2805{ 2806 Obj_Entry *root; 2807 RtldLockState lockstate; 2808 2809 wlock_acquire(rtld_bind_lock, &lockstate); 2810 root = dlcheck(handle); 2811 if (root == NULL) { 2812 lock_release(rtld_bind_lock, &lockstate); 2813 return -1; 2814 } 2815 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2816 root->path); 2817 2818 /* Unreference the object and its dependencies. */ 2819 root->dl_refcount--; 2820 2821 if (root->refcount == 1) { 2822 /* 2823 * The object will be no longer referenced, so we must unload it. 2824 * First, call the fini functions. 2825 */ 2826 objlist_call_fini(&list_fini, root, &lockstate); 2827 2828 unref_dag(root); 2829 2830 /* Finish cleaning up the newly-unreferenced objects. */ 2831 GDB_STATE(RT_DELETE,&root->linkmap); 2832 unload_object(root); 2833 GDB_STATE(RT_CONSISTENT,NULL); 2834 } else 2835 unref_dag(root); 2836 2837 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2838 lock_release(rtld_bind_lock, &lockstate); 2839 return 0; 2840} 2841 2842char * 2843dlerror(void) 2844{ 2845 char *msg = error_message; 2846 error_message = NULL; 2847 return msg; 2848} 2849 2850/* 2851 * This function is deprecated and has no effect. 2852 */ 2853void 2854dllockinit(void *context, 2855 void *(*lock_create)(void *context), 2856 void (*rlock_acquire)(void *lock), 2857 void (*wlock_acquire)(void *lock), 2858 void (*lock_release)(void *lock), 2859 void (*lock_destroy)(void *lock), 2860 void (*context_destroy)(void *context)) 2861{ 2862 static void *cur_context; 2863 static void (*cur_context_destroy)(void *); 2864 2865 /* Just destroy the context from the previous call, if necessary. */ 2866 if (cur_context_destroy != NULL) 2867 cur_context_destroy(cur_context); 2868 cur_context = context; 2869 cur_context_destroy = context_destroy; 2870} 2871 2872void * 2873dlopen(const char *name, int mode) 2874{ 2875 2876 return (rtld_dlopen(name, -1, mode)); 2877} 2878 2879void * 2880fdlopen(int fd, int mode) 2881{ 2882 2883 return (rtld_dlopen(NULL, fd, mode)); 2884} 2885 2886static void * 2887rtld_dlopen(const char *name, int fd, int mode) 2888{ 2889 RtldLockState lockstate; 2890 int lo_flags; 2891 2892 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2893 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2894 if (ld_tracing != NULL) { 2895 rlock_acquire(rtld_bind_lock, &lockstate); 2896 if (sigsetjmp(lockstate.env, 0) != 0) 2897 lock_upgrade(rtld_bind_lock, &lockstate); 2898 environ = (char **)*get_program_var_addr("environ", &lockstate); 2899 lock_release(rtld_bind_lock, &lockstate); 2900 } 2901 lo_flags = RTLD_LO_DLOPEN; 2902 if (mode & RTLD_NODELETE) 2903 lo_flags |= RTLD_LO_NODELETE; 2904 if (mode & RTLD_NOLOAD) 2905 lo_flags |= RTLD_LO_NOLOAD; 2906 if (ld_tracing != NULL) 2907 lo_flags |= RTLD_LO_TRACE; 2908 2909 return (dlopen_object(name, fd, obj_main, lo_flags, 2910 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2911} 2912 2913static void 2914dlopen_cleanup(Obj_Entry *obj) 2915{ 2916 2917 obj->dl_refcount--; 2918 unref_dag(obj); 2919 if (obj->refcount == 0) 2920 unload_object(obj); 2921} 2922 2923static Obj_Entry * 2924dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2925 int mode, RtldLockState *lockstate) 2926{ 2927 Obj_Entry **old_obj_tail; 2928 Obj_Entry *obj; 2929 Objlist initlist; 2930 RtldLockState mlockstate; 2931 int result; 2932 2933 objlist_init(&initlist); 2934 2935 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2936 wlock_acquire(rtld_bind_lock, &mlockstate); 2937 lockstate = &mlockstate; 2938 } 2939 GDB_STATE(RT_ADD,NULL); 2940 2941 old_obj_tail = obj_tail; 2942 obj = NULL; 2943 if (name == NULL && fd == -1) { 2944 obj = obj_main; 2945 obj->refcount++; 2946 } else { 2947 obj = load_object(name, fd, refobj, lo_flags); 2948 } 2949 2950 if (obj) { 2951 obj->dl_refcount++; 2952 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2953 objlist_push_tail(&list_global, obj); 2954 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2955 assert(*old_obj_tail == obj); 2956 result = load_needed_objects(obj, 2957 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2958 init_dag(obj); 2959 ref_dag(obj); 2960 if (result != -1) 2961 result = rtld_verify_versions(&obj->dagmembers); 2962 if (result != -1 && ld_tracing) 2963 goto trace; 2964 if (result == -1 || relocate_object_dag(obj, 2965 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2966 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2967 lockstate) == -1) { 2968 dlopen_cleanup(obj); 2969 obj = NULL; 2970 } else if (lo_flags & RTLD_LO_EARLY) { 2971 /* 2972 * Do not call the init functions for early loaded 2973 * filtees. The image is still not initialized enough 2974 * for them to work. 2975 * 2976 * Our object is found by the global object list and 2977 * will be ordered among all init calls done right 2978 * before transferring control to main. 2979 */ 2980 } else { 2981 /* Make list of init functions to call. */ 2982 initlist_add_objects(obj, &obj->next, &initlist); 2983 } 2984 /* 2985 * Process all no_delete or global objects here, given 2986 * them own DAGs to prevent their dependencies from being 2987 * unloaded. This has to be done after we have loaded all 2988 * of the dependencies, so that we do not miss any. 2989 */ 2990 if (obj != NULL) 2991 process_z(obj); 2992 } else { 2993 /* 2994 * Bump the reference counts for objects on this DAG. If 2995 * this is the first dlopen() call for the object that was 2996 * already loaded as a dependency, initialize the dag 2997 * starting at it. 2998 */ 2999 init_dag(obj); 3000 ref_dag(obj); 3001 3002 if ((lo_flags & RTLD_LO_TRACE) != 0) 3003 goto trace; 3004 } 3005 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3006 obj->z_nodelete) && !obj->ref_nodel) { 3007 dbg("obj %s nodelete", obj->path); 3008 ref_dag(obj); 3009 obj->z_nodelete = obj->ref_nodel = true; 3010 } 3011 } 3012 3013 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3014 name); 3015 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3016 3017 if (!(lo_flags & RTLD_LO_EARLY)) { 3018 map_stacks_exec(lockstate); 3019 } 3020 3021 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3022 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3023 lockstate) == -1) { 3024 objlist_clear(&initlist); 3025 dlopen_cleanup(obj); 3026 if (lockstate == &mlockstate) 3027 lock_release(rtld_bind_lock, lockstate); 3028 return (NULL); 3029 } 3030 3031 if (!(lo_flags & RTLD_LO_EARLY)) { 3032 /* Call the init functions. */ 3033 objlist_call_init(&initlist, lockstate); 3034 } 3035 objlist_clear(&initlist); 3036 if (lockstate == &mlockstate) 3037 lock_release(rtld_bind_lock, lockstate); 3038 return obj; 3039trace: 3040 trace_loaded_objects(obj); 3041 if (lockstate == &mlockstate) 3042 lock_release(rtld_bind_lock, lockstate); 3043 exit(0); 3044} 3045 3046static void * 3047do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3048 int flags) 3049{ 3050 DoneList donelist; 3051 const Obj_Entry *obj, *defobj; 3052 const Elf_Sym *def; 3053 SymLook req; 3054 RtldLockState lockstate; 3055#ifndef __ia64__ 3056 tls_index ti; 3057#endif 3058 int res; 3059 3060 def = NULL; 3061 defobj = NULL; 3062 symlook_init(&req, name); 3063 req.ventry = ve; 3064 req.flags = flags | SYMLOOK_IN_PLT; 3065 req.lockstate = &lockstate; 3066 3067 rlock_acquire(rtld_bind_lock, &lockstate); 3068 if (sigsetjmp(lockstate.env, 0) != 0) 3069 lock_upgrade(rtld_bind_lock, &lockstate); 3070 if (handle == NULL || handle == RTLD_NEXT || 3071 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3072 3073 if ((obj = obj_from_addr(retaddr)) == NULL) { 3074 _rtld_error("Cannot determine caller's shared object"); 3075 lock_release(rtld_bind_lock, &lockstate); 3076 return NULL; 3077 } 3078 if (handle == NULL) { /* Just the caller's shared object. */ 3079 res = symlook_obj(&req, obj); 3080 if (res == 0) { 3081 def = req.sym_out; 3082 defobj = req.defobj_out; 3083 } 3084 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3085 handle == RTLD_SELF) { /* ... caller included */ 3086 if (handle == RTLD_NEXT) 3087 obj = obj->next; 3088 for (; obj != NULL; obj = obj->next) { 3089 res = symlook_obj(&req, obj); 3090 if (res == 0) { 3091 if (def == NULL || 3092 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3093 def = req.sym_out; 3094 defobj = req.defobj_out; 3095 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3096 break; 3097 } 3098 } 3099 } 3100 /* 3101 * Search the dynamic linker itself, and possibly resolve the 3102 * symbol from there. This is how the application links to 3103 * dynamic linker services such as dlopen. 3104 */ 3105 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3106 res = symlook_obj(&req, &obj_rtld); 3107 if (res == 0) { 3108 def = req.sym_out; 3109 defobj = req.defobj_out; 3110 } 3111 } 3112 } else { 3113 assert(handle == RTLD_DEFAULT); 3114 res = symlook_default(&req, obj); 3115 if (res == 0) { 3116 defobj = req.defobj_out; 3117 def = req.sym_out; 3118 } 3119 } 3120 } else { 3121 if ((obj = dlcheck(handle)) == NULL) { 3122 lock_release(rtld_bind_lock, &lockstate); 3123 return NULL; 3124 } 3125 3126 donelist_init(&donelist); 3127 if (obj->mainprog) { 3128 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3129 res = symlook_global(&req, &donelist); 3130 if (res == 0) { 3131 def = req.sym_out; 3132 defobj = req.defobj_out; 3133 } 3134 /* 3135 * Search the dynamic linker itself, and possibly resolve the 3136 * symbol from there. This is how the application links to 3137 * dynamic linker services such as dlopen. 3138 */ 3139 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3140 res = symlook_obj(&req, &obj_rtld); 3141 if (res == 0) { 3142 def = req.sym_out; 3143 defobj = req.defobj_out; 3144 } 3145 } 3146 } 3147 else { 3148 /* Search the whole DAG rooted at the given object. */ 3149 res = symlook_list(&req, &obj->dagmembers, &donelist); 3150 if (res == 0) { 3151 def = req.sym_out; 3152 defobj = req.defobj_out; 3153 } 3154 } 3155 } 3156 3157 if (def != NULL) { 3158 lock_release(rtld_bind_lock, &lockstate); 3159 3160 /* 3161 * The value required by the caller is derived from the value 3162 * of the symbol. For the ia64 architecture, we need to 3163 * construct a function descriptor which the caller can use to 3164 * call the function with the right 'gp' value. For other 3165 * architectures and for non-functions, the value is simply 3166 * the relocated value of the symbol. 3167 */ 3168 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3169 return (make_function_pointer(def, defobj)); 3170 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3171 return (rtld_resolve_ifunc(defobj, def)); 3172 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3173#ifdef __ia64__ 3174 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3175#else 3176 ti.ti_module = defobj->tlsindex; 3177 ti.ti_offset = def->st_value; 3178 return (__tls_get_addr(&ti)); 3179#endif 3180 } else 3181 return (defobj->relocbase + def->st_value); 3182 } 3183 3184 _rtld_error("Undefined symbol \"%s\"", name); 3185 lock_release(rtld_bind_lock, &lockstate); 3186 return NULL; 3187} 3188 3189void * 3190dlsym(void *handle, const char *name) 3191{ 3192 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3193 SYMLOOK_DLSYM); 3194} 3195 3196dlfunc_t 3197dlfunc(void *handle, const char *name) 3198{ 3199 union { 3200 void *d; 3201 dlfunc_t f; 3202 } rv; 3203 3204 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3205 SYMLOOK_DLSYM); 3206 return (rv.f); 3207} 3208 3209void * 3210dlvsym(void *handle, const char *name, const char *version) 3211{ 3212 Ver_Entry ventry; 3213 3214 ventry.name = version; 3215 ventry.file = NULL; 3216 ventry.hash = elf_hash(version); 3217 ventry.flags= 0; 3218 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3219 SYMLOOK_DLSYM); 3220} 3221 3222int 3223_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3224{ 3225 const Obj_Entry *obj; 3226 RtldLockState lockstate; 3227 3228 rlock_acquire(rtld_bind_lock, &lockstate); 3229 obj = obj_from_addr(addr); 3230 if (obj == NULL) { 3231 _rtld_error("No shared object contains address"); 3232 lock_release(rtld_bind_lock, &lockstate); 3233 return (0); 3234 } 3235 rtld_fill_dl_phdr_info(obj, phdr_info); 3236 lock_release(rtld_bind_lock, &lockstate); 3237 return (1); 3238} 3239 3240int 3241dladdr(const void *addr, Dl_info *info) 3242{ 3243 const Obj_Entry *obj; 3244 const Elf_Sym *def; 3245 void *symbol_addr; 3246 unsigned long symoffset; 3247 RtldLockState lockstate; 3248 3249 rlock_acquire(rtld_bind_lock, &lockstate); 3250 obj = obj_from_addr(addr); 3251 if (obj == NULL) { 3252 _rtld_error("No shared object contains address"); 3253 lock_release(rtld_bind_lock, &lockstate); 3254 return 0; 3255 } 3256 info->dli_fname = obj->path; 3257 info->dli_fbase = obj->mapbase; 3258 info->dli_saddr = (void *)0; 3259 info->dli_sname = NULL; 3260 3261 /* 3262 * Walk the symbol list looking for the symbol whose address is 3263 * closest to the address sent in. 3264 */ 3265 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3266 def = obj->symtab + symoffset; 3267 3268 /* 3269 * For skip the symbol if st_shndx is either SHN_UNDEF or 3270 * SHN_COMMON. 3271 */ 3272 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3273 continue; 3274 3275 /* 3276 * If the symbol is greater than the specified address, or if it 3277 * is further away from addr than the current nearest symbol, 3278 * then reject it. 3279 */ 3280 symbol_addr = obj->relocbase + def->st_value; 3281 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3282 continue; 3283 3284 /* Update our idea of the nearest symbol. */ 3285 info->dli_sname = obj->strtab + def->st_name; 3286 info->dli_saddr = symbol_addr; 3287 3288 /* Exact match? */ 3289 if (info->dli_saddr == addr) 3290 break; 3291 } 3292 lock_release(rtld_bind_lock, &lockstate); 3293 return 1; 3294} 3295 3296int 3297dlinfo(void *handle, int request, void *p) 3298{ 3299 const Obj_Entry *obj; 3300 RtldLockState lockstate; 3301 int error; 3302 3303 rlock_acquire(rtld_bind_lock, &lockstate); 3304 3305 if (handle == NULL || handle == RTLD_SELF) { 3306 void *retaddr; 3307 3308 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3309 if ((obj = obj_from_addr(retaddr)) == NULL) 3310 _rtld_error("Cannot determine caller's shared object"); 3311 } else 3312 obj = dlcheck(handle); 3313 3314 if (obj == NULL) { 3315 lock_release(rtld_bind_lock, &lockstate); 3316 return (-1); 3317 } 3318 3319 error = 0; 3320 switch (request) { 3321 case RTLD_DI_LINKMAP: 3322 *((struct link_map const **)p) = &obj->linkmap; 3323 break; 3324 case RTLD_DI_ORIGIN: 3325 error = rtld_dirname(obj->path, p); 3326 break; 3327 3328 case RTLD_DI_SERINFOSIZE: 3329 case RTLD_DI_SERINFO: 3330 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3331 break; 3332 3333 default: 3334 _rtld_error("Invalid request %d passed to dlinfo()", request); 3335 error = -1; 3336 } 3337 3338 lock_release(rtld_bind_lock, &lockstate); 3339 3340 return (error); 3341} 3342 3343static void 3344rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3345{ 3346 3347 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3348 phdr_info->dlpi_name = obj->path; 3349 phdr_info->dlpi_phdr = obj->phdr; 3350 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3351 phdr_info->dlpi_tls_modid = obj->tlsindex; 3352 phdr_info->dlpi_tls_data = obj->tlsinit; 3353 phdr_info->dlpi_adds = obj_loads; 3354 phdr_info->dlpi_subs = obj_loads - obj_count; 3355} 3356 3357int 3358dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3359{ 3360 struct dl_phdr_info phdr_info; 3361 const Obj_Entry *obj; 3362 RtldLockState bind_lockstate, phdr_lockstate; 3363 int error; 3364 3365 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3366 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3367 3368 error = 0; 3369 3370 for (obj = obj_list; obj != NULL; obj = obj->next) { 3371 rtld_fill_dl_phdr_info(obj, &phdr_info); 3372 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3373 break; 3374 3375 } 3376 lock_release(rtld_bind_lock, &bind_lockstate); 3377 lock_release(rtld_phdr_lock, &phdr_lockstate); 3378 3379 return (error); 3380} 3381 3382static void * 3383fill_search_info(const char *dir, size_t dirlen, void *param) 3384{ 3385 struct fill_search_info_args *arg; 3386 3387 arg = param; 3388 3389 if (arg->request == RTLD_DI_SERINFOSIZE) { 3390 arg->serinfo->dls_cnt ++; 3391 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3392 } else { 3393 struct dl_serpath *s_entry; 3394 3395 s_entry = arg->serpath; 3396 s_entry->dls_name = arg->strspace; 3397 s_entry->dls_flags = arg->flags; 3398 3399 strncpy(arg->strspace, dir, dirlen); 3400 arg->strspace[dirlen] = '\0'; 3401 3402 arg->strspace += dirlen + 1; 3403 arg->serpath++; 3404 } 3405 3406 return (NULL); 3407} 3408 3409static int 3410do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3411{ 3412 struct dl_serinfo _info; 3413 struct fill_search_info_args args; 3414 3415 args.request = RTLD_DI_SERINFOSIZE; 3416 args.serinfo = &_info; 3417 3418 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3419 _info.dls_cnt = 0; 3420 3421 path_enumerate(obj->rpath, fill_search_info, &args); 3422 path_enumerate(ld_library_path, fill_search_info, &args); 3423 path_enumerate(obj->runpath, fill_search_info, &args); 3424 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3425 if (!obj->z_nodeflib) 3426 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3427 3428 3429 if (request == RTLD_DI_SERINFOSIZE) { 3430 info->dls_size = _info.dls_size; 3431 info->dls_cnt = _info.dls_cnt; 3432 return (0); 3433 } 3434 3435 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3436 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3437 return (-1); 3438 } 3439 3440 args.request = RTLD_DI_SERINFO; 3441 args.serinfo = info; 3442 args.serpath = &info->dls_serpath[0]; 3443 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3444 3445 args.flags = LA_SER_RUNPATH; 3446 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3447 return (-1); 3448 3449 args.flags = LA_SER_LIBPATH; 3450 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3451 return (-1); 3452 3453 args.flags = LA_SER_RUNPATH; 3454 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3455 return (-1); 3456 3457 args.flags = LA_SER_CONFIG; 3458 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3459 != NULL) 3460 return (-1); 3461 3462 args.flags = LA_SER_DEFAULT; 3463 if (!obj->z_nodeflib && 3464 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3465 return (-1); 3466 return (0); 3467} 3468 3469static int 3470rtld_dirname(const char *path, char *bname) 3471{ 3472 const char *endp; 3473 3474 /* Empty or NULL string gets treated as "." */ 3475 if (path == NULL || *path == '\0') { 3476 bname[0] = '.'; 3477 bname[1] = '\0'; 3478 return (0); 3479 } 3480 3481 /* Strip trailing slashes */ 3482 endp = path + strlen(path) - 1; 3483 while (endp > path && *endp == '/') 3484 endp--; 3485 3486 /* Find the start of the dir */ 3487 while (endp > path && *endp != '/') 3488 endp--; 3489 3490 /* Either the dir is "/" or there are no slashes */ 3491 if (endp == path) { 3492 bname[0] = *endp == '/' ? '/' : '.'; 3493 bname[1] = '\0'; 3494 return (0); 3495 } else { 3496 do { 3497 endp--; 3498 } while (endp > path && *endp == '/'); 3499 } 3500 3501 if (endp - path + 2 > PATH_MAX) 3502 { 3503 _rtld_error("Filename is too long: %s", path); 3504 return(-1); 3505 } 3506 3507 strncpy(bname, path, endp - path + 1); 3508 bname[endp - path + 1] = '\0'; 3509 return (0); 3510} 3511 3512static int 3513rtld_dirname_abs(const char *path, char *base) 3514{ 3515 char *last; 3516 3517 if (realpath(path, base) == NULL) 3518 return (-1); 3519 dbg("%s -> %s", path, base); 3520 last = strrchr(base, '/'); 3521 if (last == NULL) 3522 return (-1); 3523 if (last != base) 3524 *last = '\0'; 3525 return (0); 3526} 3527 3528static void 3529linkmap_add(Obj_Entry *obj) 3530{ 3531 struct link_map *l = &obj->linkmap; 3532 struct link_map *prev; 3533 3534 obj->linkmap.l_name = obj->path; 3535 obj->linkmap.l_addr = obj->mapbase; 3536 obj->linkmap.l_ld = obj->dynamic; 3537#ifdef __mips__ 3538 /* GDB needs load offset on MIPS to use the symbols */ 3539 obj->linkmap.l_offs = obj->relocbase; 3540#endif 3541 3542 if (r_debug.r_map == NULL) { 3543 r_debug.r_map = l; 3544 return; 3545 } 3546 3547 /* 3548 * Scan to the end of the list, but not past the entry for the 3549 * dynamic linker, which we want to keep at the very end. 3550 */ 3551 for (prev = r_debug.r_map; 3552 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3553 prev = prev->l_next) 3554 ; 3555 3556 /* Link in the new entry. */ 3557 l->l_prev = prev; 3558 l->l_next = prev->l_next; 3559 if (l->l_next != NULL) 3560 l->l_next->l_prev = l; 3561 prev->l_next = l; 3562} 3563 3564static void 3565linkmap_delete(Obj_Entry *obj) 3566{ 3567 struct link_map *l = &obj->linkmap; 3568 3569 if (l->l_prev == NULL) { 3570 if ((r_debug.r_map = l->l_next) != NULL) 3571 l->l_next->l_prev = NULL; 3572 return; 3573 } 3574 3575 if ((l->l_prev->l_next = l->l_next) != NULL) 3576 l->l_next->l_prev = l->l_prev; 3577} 3578 3579/* 3580 * Function for the debugger to set a breakpoint on to gain control. 3581 * 3582 * The two parameters allow the debugger to easily find and determine 3583 * what the runtime loader is doing and to whom it is doing it. 3584 * 3585 * When the loadhook trap is hit (r_debug_state, set at program 3586 * initialization), the arguments can be found on the stack: 3587 * 3588 * +8 struct link_map *m 3589 * +4 struct r_debug *rd 3590 * +0 RetAddr 3591 */ 3592void 3593r_debug_state(struct r_debug* rd, struct link_map *m) 3594{ 3595 /* 3596 * The following is a hack to force the compiler to emit calls to 3597 * this function, even when optimizing. If the function is empty, 3598 * the compiler is not obliged to emit any code for calls to it, 3599 * even when marked __noinline. However, gdb depends on those 3600 * calls being made. 3601 */ 3602 __compiler_membar(); 3603} 3604 3605/* 3606 * A function called after init routines have completed. This can be used to 3607 * break before a program's entry routine is called, and can be used when 3608 * main is not available in the symbol table. 3609 */ 3610void 3611_r_debug_postinit(struct link_map *m) 3612{ 3613 3614 /* See r_debug_state(). */ 3615 __compiler_membar(); 3616} 3617 3618/* 3619 * Get address of the pointer variable in the main program. 3620 * Prefer non-weak symbol over the weak one. 3621 */ 3622static const void ** 3623get_program_var_addr(const char *name, RtldLockState *lockstate) 3624{ 3625 SymLook req; 3626 DoneList donelist; 3627 3628 symlook_init(&req, name); 3629 req.lockstate = lockstate; 3630 donelist_init(&donelist); 3631 if (symlook_global(&req, &donelist) != 0) 3632 return (NULL); 3633 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3634 return ((const void **)make_function_pointer(req.sym_out, 3635 req.defobj_out)); 3636 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3637 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3638 else 3639 return ((const void **)(req.defobj_out->relocbase + 3640 req.sym_out->st_value)); 3641} 3642 3643/* 3644 * Set a pointer variable in the main program to the given value. This 3645 * is used to set key variables such as "environ" before any of the 3646 * init functions are called. 3647 */ 3648static void 3649set_program_var(const char *name, const void *value) 3650{ 3651 const void **addr; 3652 3653 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3654 dbg("\"%s\": *%p <-- %p", name, addr, value); 3655 *addr = value; 3656 } 3657} 3658 3659/* 3660 * Search the global objects, including dependencies and main object, 3661 * for the given symbol. 3662 */ 3663static int 3664symlook_global(SymLook *req, DoneList *donelist) 3665{ 3666 SymLook req1; 3667 const Objlist_Entry *elm; 3668 int res; 3669 3670 symlook_init_from_req(&req1, req); 3671 3672 /* Search all objects loaded at program start up. */ 3673 if (req->defobj_out == NULL || 3674 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3675 res = symlook_list(&req1, &list_main, donelist); 3676 if (res == 0 && (req->defobj_out == NULL || 3677 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3678 req->sym_out = req1.sym_out; 3679 req->defobj_out = req1.defobj_out; 3680 assert(req->defobj_out != NULL); 3681 } 3682 } 3683 3684 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3685 STAILQ_FOREACH(elm, &list_global, link) { 3686 if (req->defobj_out != NULL && 3687 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3688 break; 3689 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3690 if (res == 0 && (req->defobj_out == NULL || 3691 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3692 req->sym_out = req1.sym_out; 3693 req->defobj_out = req1.defobj_out; 3694 assert(req->defobj_out != NULL); 3695 } 3696 } 3697 3698 return (req->sym_out != NULL ? 0 : ESRCH); 3699} 3700 3701/* 3702 * Given a symbol name in a referencing object, find the corresponding 3703 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3704 * no definition was found. Returns a pointer to the Obj_Entry of the 3705 * defining object via the reference parameter DEFOBJ_OUT. 3706 */ 3707static int 3708symlook_default(SymLook *req, const Obj_Entry *refobj) 3709{ 3710 DoneList donelist; 3711 const Objlist_Entry *elm; 3712 SymLook req1; 3713 int res; 3714 3715 donelist_init(&donelist); 3716 symlook_init_from_req(&req1, req); 3717 3718 /* Look first in the referencing object if linked symbolically. */ 3719 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3720 res = symlook_obj(&req1, refobj); 3721 if (res == 0) { 3722 req->sym_out = req1.sym_out; 3723 req->defobj_out = req1.defobj_out; 3724 assert(req->defobj_out != NULL); 3725 } 3726 } 3727 3728 symlook_global(req, &donelist); 3729 3730 /* Search all dlopened DAGs containing the referencing object. */ 3731 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3732 if (req->sym_out != NULL && 3733 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3734 break; 3735 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3736 if (res == 0 && (req->sym_out == NULL || 3737 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3738 req->sym_out = req1.sym_out; 3739 req->defobj_out = req1.defobj_out; 3740 assert(req->defobj_out != NULL); 3741 } 3742 } 3743 3744 /* 3745 * Search the dynamic linker itself, and possibly resolve the 3746 * symbol from there. This is how the application links to 3747 * dynamic linker services such as dlopen. 3748 */ 3749 if (req->sym_out == NULL || 3750 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3751 res = symlook_obj(&req1, &obj_rtld); 3752 if (res == 0) { 3753 req->sym_out = req1.sym_out; 3754 req->defobj_out = req1.defobj_out; 3755 assert(req->defobj_out != NULL); 3756 } 3757 } 3758 3759 return (req->sym_out != NULL ? 0 : ESRCH); 3760} 3761 3762static int 3763symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3764{ 3765 const Elf_Sym *def; 3766 const Obj_Entry *defobj; 3767 const Objlist_Entry *elm; 3768 SymLook req1; 3769 int res; 3770 3771 def = NULL; 3772 defobj = NULL; 3773 STAILQ_FOREACH(elm, objlist, link) { 3774 if (donelist_check(dlp, elm->obj)) 3775 continue; 3776 symlook_init_from_req(&req1, req); 3777 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3778 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3779 def = req1.sym_out; 3780 defobj = req1.defobj_out; 3781 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3782 break; 3783 } 3784 } 3785 } 3786 if (def != NULL) { 3787 req->sym_out = def; 3788 req->defobj_out = defobj; 3789 return (0); 3790 } 3791 return (ESRCH); 3792} 3793 3794/* 3795 * Search the chain of DAGS cointed to by the given Needed_Entry 3796 * for a symbol of the given name. Each DAG is scanned completely 3797 * before advancing to the next one. Returns a pointer to the symbol, 3798 * or NULL if no definition was found. 3799 */ 3800static int 3801symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3802{ 3803 const Elf_Sym *def; 3804 const Needed_Entry *n; 3805 const Obj_Entry *defobj; 3806 SymLook req1; 3807 int res; 3808 3809 def = NULL; 3810 defobj = NULL; 3811 symlook_init_from_req(&req1, req); 3812 for (n = needed; n != NULL; n = n->next) { 3813 if (n->obj == NULL || 3814 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3815 continue; 3816 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3817 def = req1.sym_out; 3818 defobj = req1.defobj_out; 3819 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3820 break; 3821 } 3822 } 3823 if (def != NULL) { 3824 req->sym_out = def; 3825 req->defobj_out = defobj; 3826 return (0); 3827 } 3828 return (ESRCH); 3829} 3830 3831/* 3832 * Search the symbol table of a single shared object for a symbol of 3833 * the given name and version, if requested. Returns a pointer to the 3834 * symbol, or NULL if no definition was found. If the object is 3835 * filter, return filtered symbol from filtee. 3836 * 3837 * The symbol's hash value is passed in for efficiency reasons; that 3838 * eliminates many recomputations of the hash value. 3839 */ 3840int 3841symlook_obj(SymLook *req, const Obj_Entry *obj) 3842{ 3843 DoneList donelist; 3844 SymLook req1; 3845 int flags, res, mres; 3846 3847 /* 3848 * If there is at least one valid hash at this point, we prefer to 3849 * use the faster GNU version if available. 3850 */ 3851 if (obj->valid_hash_gnu) 3852 mres = symlook_obj1_gnu(req, obj); 3853 else if (obj->valid_hash_sysv) 3854 mres = symlook_obj1_sysv(req, obj); 3855 else 3856 return (EINVAL); 3857 3858 if (mres == 0) { 3859 if (obj->needed_filtees != NULL) { 3860 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3861 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3862 donelist_init(&donelist); 3863 symlook_init_from_req(&req1, req); 3864 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3865 if (res == 0) { 3866 req->sym_out = req1.sym_out; 3867 req->defobj_out = req1.defobj_out; 3868 } 3869 return (res); 3870 } 3871 if (obj->needed_aux_filtees != NULL) { 3872 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3873 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3874 donelist_init(&donelist); 3875 symlook_init_from_req(&req1, req); 3876 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3877 if (res == 0) { 3878 req->sym_out = req1.sym_out; 3879 req->defobj_out = req1.defobj_out; 3880 return (res); 3881 } 3882 } 3883 } 3884 return (mres); 3885} 3886 3887/* Symbol match routine common to both hash functions */ 3888static bool 3889matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3890 const unsigned long symnum) 3891{ 3892 Elf_Versym verndx; 3893 const Elf_Sym *symp; 3894 const char *strp; 3895 3896 symp = obj->symtab + symnum; 3897 strp = obj->strtab + symp->st_name; 3898 3899 switch (ELF_ST_TYPE(symp->st_info)) { 3900 case STT_FUNC: 3901 case STT_NOTYPE: 3902 case STT_OBJECT: 3903 case STT_COMMON: 3904 case STT_GNU_IFUNC: 3905 if (symp->st_value == 0) 3906 return (false); 3907 /* fallthrough */ 3908 case STT_TLS: 3909 if (symp->st_shndx != SHN_UNDEF) 3910 break; 3911#ifndef __mips__ 3912 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3913 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3914 break; 3915 /* fallthrough */ 3916#endif 3917 default: 3918 return (false); 3919 } 3920 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3921 return (false); 3922 3923 if (req->ventry == NULL) { 3924 if (obj->versyms != NULL) { 3925 verndx = VER_NDX(obj->versyms[symnum]); 3926 if (verndx > obj->vernum) { 3927 _rtld_error( 3928 "%s: symbol %s references wrong version %d", 3929 obj->path, obj->strtab + symnum, verndx); 3930 return (false); 3931 } 3932 /* 3933 * If we are not called from dlsym (i.e. this 3934 * is a normal relocation from unversioned 3935 * binary), accept the symbol immediately if 3936 * it happens to have first version after this 3937 * shared object became versioned. Otherwise, 3938 * if symbol is versioned and not hidden, 3939 * remember it. If it is the only symbol with 3940 * this name exported by the shared object, it 3941 * will be returned as a match by the calling 3942 * function. If symbol is global (verndx < 2) 3943 * accept it unconditionally. 3944 */ 3945 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3946 verndx == VER_NDX_GIVEN) { 3947 result->sym_out = symp; 3948 return (true); 3949 } 3950 else if (verndx >= VER_NDX_GIVEN) { 3951 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3952 == 0) { 3953 if (result->vsymp == NULL) 3954 result->vsymp = symp; 3955 result->vcount++; 3956 } 3957 return (false); 3958 } 3959 } 3960 result->sym_out = symp; 3961 return (true); 3962 } 3963 if (obj->versyms == NULL) { 3964 if (object_match_name(obj, req->ventry->name)) { 3965 _rtld_error("%s: object %s should provide version %s " 3966 "for symbol %s", obj_rtld.path, obj->path, 3967 req->ventry->name, obj->strtab + symnum); 3968 return (false); 3969 } 3970 } else { 3971 verndx = VER_NDX(obj->versyms[symnum]); 3972 if (verndx > obj->vernum) { 3973 _rtld_error("%s: symbol %s references wrong version %d", 3974 obj->path, obj->strtab + symnum, verndx); 3975 return (false); 3976 } 3977 if (obj->vertab[verndx].hash != req->ventry->hash || 3978 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3979 /* 3980 * Version does not match. Look if this is a 3981 * global symbol and if it is not hidden. If 3982 * global symbol (verndx < 2) is available, 3983 * use it. Do not return symbol if we are 3984 * called by dlvsym, because dlvsym looks for 3985 * a specific version and default one is not 3986 * what dlvsym wants. 3987 */ 3988 if ((req->flags & SYMLOOK_DLSYM) || 3989 (verndx >= VER_NDX_GIVEN) || 3990 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3991 return (false); 3992 } 3993 } 3994 result->sym_out = symp; 3995 return (true); 3996} 3997 3998/* 3999 * Search for symbol using SysV hash function. 4000 * obj->buckets is known not to be NULL at this point; the test for this was 4001 * performed with the obj->valid_hash_sysv assignment. 4002 */ 4003static int 4004symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4005{ 4006 unsigned long symnum; 4007 Sym_Match_Result matchres; 4008 4009 matchres.sym_out = NULL; 4010 matchres.vsymp = NULL; 4011 matchres.vcount = 0; 4012 4013 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4014 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4015 if (symnum >= obj->nchains) 4016 return (ESRCH); /* Bad object */ 4017 4018 if (matched_symbol(req, obj, &matchres, symnum)) { 4019 req->sym_out = matchres.sym_out; 4020 req->defobj_out = obj; 4021 return (0); 4022 } 4023 } 4024 if (matchres.vcount == 1) { 4025 req->sym_out = matchres.vsymp; 4026 req->defobj_out = obj; 4027 return (0); 4028 } 4029 return (ESRCH); 4030} 4031 4032/* Search for symbol using GNU hash function */ 4033static int 4034symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4035{ 4036 Elf_Addr bloom_word; 4037 const Elf32_Word *hashval; 4038 Elf32_Word bucket; 4039 Sym_Match_Result matchres; 4040 unsigned int h1, h2; 4041 unsigned long symnum; 4042 4043 matchres.sym_out = NULL; 4044 matchres.vsymp = NULL; 4045 matchres.vcount = 0; 4046 4047 /* Pick right bitmask word from Bloom filter array */ 4048 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4049 obj->maskwords_bm_gnu]; 4050 4051 /* Calculate modulus word size of gnu hash and its derivative */ 4052 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4053 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4054 4055 /* Filter out the "definitely not in set" queries */ 4056 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4057 return (ESRCH); 4058 4059 /* Locate hash chain and corresponding value element*/ 4060 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4061 if (bucket == 0) 4062 return (ESRCH); 4063 hashval = &obj->chain_zero_gnu[bucket]; 4064 do { 4065 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4066 symnum = hashval - obj->chain_zero_gnu; 4067 if (matched_symbol(req, obj, &matchres, symnum)) { 4068 req->sym_out = matchres.sym_out; 4069 req->defobj_out = obj; 4070 return (0); 4071 } 4072 } 4073 } while ((*hashval++ & 1) == 0); 4074 if (matchres.vcount == 1) { 4075 req->sym_out = matchres.vsymp; 4076 req->defobj_out = obj; 4077 return (0); 4078 } 4079 return (ESRCH); 4080} 4081 4082static void 4083trace_loaded_objects(Obj_Entry *obj) 4084{ 4085 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4086 int c; 4087 4088 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4089 main_local = ""; 4090 4091 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4092 fmt1 = "\t%o => %p (%x)\n"; 4093 4094 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4095 fmt2 = "\t%o (%x)\n"; 4096 4097 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4098 4099 for (; obj; obj = obj->next) { 4100 Needed_Entry *needed; 4101 char *name, *path; 4102 bool is_lib; 4103 4104 if (list_containers && obj->needed != NULL) 4105 rtld_printf("%s:\n", obj->path); 4106 for (needed = obj->needed; needed; needed = needed->next) { 4107 if (needed->obj != NULL) { 4108 if (needed->obj->traced && !list_containers) 4109 continue; 4110 needed->obj->traced = true; 4111 path = needed->obj->path; 4112 } else 4113 path = "not found"; 4114 4115 name = (char *)obj->strtab + needed->name; 4116 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4117 4118 fmt = is_lib ? fmt1 : fmt2; 4119 while ((c = *fmt++) != '\0') { 4120 switch (c) { 4121 default: 4122 rtld_putchar(c); 4123 continue; 4124 case '\\': 4125 switch (c = *fmt) { 4126 case '\0': 4127 continue; 4128 case 'n': 4129 rtld_putchar('\n'); 4130 break; 4131 case 't': 4132 rtld_putchar('\t'); 4133 break; 4134 } 4135 break; 4136 case '%': 4137 switch (c = *fmt) { 4138 case '\0': 4139 continue; 4140 case '%': 4141 default: 4142 rtld_putchar(c); 4143 break; 4144 case 'A': 4145 rtld_putstr(main_local); 4146 break; 4147 case 'a': 4148 rtld_putstr(obj_main->path); 4149 break; 4150 case 'o': 4151 rtld_putstr(name); 4152 break; 4153#if 0 4154 case 'm': 4155 rtld_printf("%d", sodp->sod_major); 4156 break; 4157 case 'n': 4158 rtld_printf("%d", sodp->sod_minor); 4159 break; 4160#endif 4161 case 'p': 4162 rtld_putstr(path); 4163 break; 4164 case 'x': 4165 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4166 0); 4167 break; 4168 } 4169 break; 4170 } 4171 ++fmt; 4172 } 4173 } 4174 } 4175} 4176 4177/* 4178 * Unload a dlopened object and its dependencies from memory and from 4179 * our data structures. It is assumed that the DAG rooted in the 4180 * object has already been unreferenced, and that the object has a 4181 * reference count of 0. 4182 */ 4183static void 4184unload_object(Obj_Entry *root) 4185{ 4186 Obj_Entry *obj; 4187 Obj_Entry **linkp; 4188 4189 assert(root->refcount == 0); 4190 4191 /* 4192 * Pass over the DAG removing unreferenced objects from 4193 * appropriate lists. 4194 */ 4195 unlink_object(root); 4196 4197 /* Unmap all objects that are no longer referenced. */ 4198 linkp = &obj_list->next; 4199 while ((obj = *linkp) != NULL) { 4200 if (obj->refcount == 0) { 4201 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4202 obj->path); 4203 dbg("unloading \"%s\"", obj->path); 4204 unload_filtees(root); 4205 munmap(obj->mapbase, obj->mapsize); 4206 linkmap_delete(obj); 4207 *linkp = obj->next; 4208 obj_count--; 4209 obj_free(obj); 4210 } else 4211 linkp = &obj->next; 4212 } 4213 obj_tail = linkp; 4214} 4215 4216static void 4217unlink_object(Obj_Entry *root) 4218{ 4219 Objlist_Entry *elm; 4220 4221 if (root->refcount == 0) { 4222 /* Remove the object from the RTLD_GLOBAL list. */ 4223 objlist_remove(&list_global, root); 4224 4225 /* Remove the object from all objects' DAG lists. */ 4226 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4227 objlist_remove(&elm->obj->dldags, root); 4228 if (elm->obj != root) 4229 unlink_object(elm->obj); 4230 } 4231 } 4232} 4233 4234static void 4235ref_dag(Obj_Entry *root) 4236{ 4237 Objlist_Entry *elm; 4238 4239 assert(root->dag_inited); 4240 STAILQ_FOREACH(elm, &root->dagmembers, link) 4241 elm->obj->refcount++; 4242} 4243 4244static void 4245unref_dag(Obj_Entry *root) 4246{ 4247 Objlist_Entry *elm; 4248 4249 assert(root->dag_inited); 4250 STAILQ_FOREACH(elm, &root->dagmembers, link) 4251 elm->obj->refcount--; 4252} 4253 4254/* 4255 * Common code for MD __tls_get_addr(). 4256 */ 4257static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4258static void * 4259tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4260{ 4261 Elf_Addr *newdtv, *dtv; 4262 RtldLockState lockstate; 4263 int to_copy; 4264 4265 dtv = *dtvp; 4266 /* Check dtv generation in case new modules have arrived */ 4267 if (dtv[0] != tls_dtv_generation) { 4268 wlock_acquire(rtld_bind_lock, &lockstate); 4269 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4270 to_copy = dtv[1]; 4271 if (to_copy > tls_max_index) 4272 to_copy = tls_max_index; 4273 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4274 newdtv[0] = tls_dtv_generation; 4275 newdtv[1] = tls_max_index; 4276 free(dtv); 4277 lock_release(rtld_bind_lock, &lockstate); 4278 dtv = *dtvp = newdtv; 4279 } 4280 4281 /* Dynamically allocate module TLS if necessary */ 4282 if (dtv[index + 1] == 0) { 4283 /* Signal safe, wlock will block out signals. */ 4284 wlock_acquire(rtld_bind_lock, &lockstate); 4285 if (!dtv[index + 1]) 4286 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4287 lock_release(rtld_bind_lock, &lockstate); 4288 } 4289 return ((void *)(dtv[index + 1] + offset)); 4290} 4291 4292void * 4293tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4294{ 4295 Elf_Addr *dtv; 4296 4297 dtv = *dtvp; 4298 /* Check dtv generation in case new modules have arrived */ 4299 if (__predict_true(dtv[0] == tls_dtv_generation && 4300 dtv[index + 1] != 0)) 4301 return ((void *)(dtv[index + 1] + offset)); 4302 return (tls_get_addr_slow(dtvp, index, offset)); 4303} 4304 4305#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4306 4307/* 4308 * Allocate Static TLS using the Variant I method. 4309 */ 4310void * 4311allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4312{ 4313 Obj_Entry *obj; 4314 char *tcb; 4315 Elf_Addr **tls; 4316 Elf_Addr *dtv; 4317 Elf_Addr addr; 4318 int i; 4319 4320 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4321 return (oldtcb); 4322 4323 assert(tcbsize >= TLS_TCB_SIZE); 4324 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4325 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4326 4327 if (oldtcb != NULL) { 4328 memcpy(tls, oldtcb, tls_static_space); 4329 free(oldtcb); 4330 4331 /* Adjust the DTV. */ 4332 dtv = tls[0]; 4333 for (i = 0; i < dtv[1]; i++) { 4334 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4335 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4336 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4337 } 4338 } 4339 } else { 4340 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4341 tls[0] = dtv; 4342 dtv[0] = tls_dtv_generation; 4343 dtv[1] = tls_max_index; 4344 4345 for (obj = objs; obj; obj = obj->next) { 4346 if (obj->tlsoffset > 0) { 4347 addr = (Elf_Addr)tls + obj->tlsoffset; 4348 if (obj->tlsinitsize > 0) 4349 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4350 if (obj->tlssize > obj->tlsinitsize) 4351 memset((void*) (addr + obj->tlsinitsize), 0, 4352 obj->tlssize - obj->tlsinitsize); 4353 dtv[obj->tlsindex + 1] = addr; 4354 } 4355 } 4356 } 4357 4358 return (tcb); 4359} 4360 4361void 4362free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4363{ 4364 Elf_Addr *dtv; 4365 Elf_Addr tlsstart, tlsend; 4366 int dtvsize, i; 4367 4368 assert(tcbsize >= TLS_TCB_SIZE); 4369 4370 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4371 tlsend = tlsstart + tls_static_space; 4372 4373 dtv = *(Elf_Addr **)tlsstart; 4374 dtvsize = dtv[1]; 4375 for (i = 0; i < dtvsize; i++) { 4376 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4377 free((void*)dtv[i+2]); 4378 } 4379 } 4380 free(dtv); 4381 free(tcb); 4382} 4383 4384#endif 4385 4386#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4387 4388/* 4389 * Allocate Static TLS using the Variant II method. 4390 */ 4391void * 4392allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4393{ 4394 Obj_Entry *obj; 4395 size_t size, ralign; 4396 char *tls; 4397 Elf_Addr *dtv, *olddtv; 4398 Elf_Addr segbase, oldsegbase, addr; 4399 int i; 4400 4401 ralign = tcbalign; 4402 if (tls_static_max_align > ralign) 4403 ralign = tls_static_max_align; 4404 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4405 4406 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4407 tls = malloc_aligned(size, ralign); 4408 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4409 4410 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4411 ((Elf_Addr*)segbase)[0] = segbase; 4412 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4413 4414 dtv[0] = tls_dtv_generation; 4415 dtv[1] = tls_max_index; 4416 4417 if (oldtls) { 4418 /* 4419 * Copy the static TLS block over whole. 4420 */ 4421 oldsegbase = (Elf_Addr) oldtls; 4422 memcpy((void *)(segbase - tls_static_space), 4423 (const void *)(oldsegbase - tls_static_space), 4424 tls_static_space); 4425 4426 /* 4427 * If any dynamic TLS blocks have been created tls_get_addr(), 4428 * move them over. 4429 */ 4430 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4431 for (i = 0; i < olddtv[1]; i++) { 4432 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4433 dtv[i+2] = olddtv[i+2]; 4434 olddtv[i+2] = 0; 4435 } 4436 } 4437 4438 /* 4439 * We assume that this block was the one we created with 4440 * allocate_initial_tls(). 4441 */ 4442 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4443 } else { 4444 for (obj = objs; obj; obj = obj->next) { 4445 if (obj->tlsoffset) { 4446 addr = segbase - obj->tlsoffset; 4447 memset((void*) (addr + obj->tlsinitsize), 4448 0, obj->tlssize - obj->tlsinitsize); 4449 if (obj->tlsinit) 4450 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4451 dtv[obj->tlsindex + 1] = addr; 4452 } 4453 } 4454 } 4455 4456 return (void*) segbase; 4457} 4458 4459void 4460free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4461{ 4462 Elf_Addr* dtv; 4463 size_t size, ralign; 4464 int dtvsize, i; 4465 Elf_Addr tlsstart, tlsend; 4466 4467 /* 4468 * Figure out the size of the initial TLS block so that we can 4469 * find stuff which ___tls_get_addr() allocated dynamically. 4470 */ 4471 ralign = tcbalign; 4472 if (tls_static_max_align > ralign) 4473 ralign = tls_static_max_align; 4474 size = round(tls_static_space, ralign); 4475 4476 dtv = ((Elf_Addr**)tls)[1]; 4477 dtvsize = dtv[1]; 4478 tlsend = (Elf_Addr) tls; 4479 tlsstart = tlsend - size; 4480 for (i = 0; i < dtvsize; i++) { 4481 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4482 free_aligned((void *)dtv[i + 2]); 4483 } 4484 } 4485 4486 free_aligned((void *)tlsstart); 4487 free((void*) dtv); 4488} 4489 4490#endif 4491 4492/* 4493 * Allocate TLS block for module with given index. 4494 */ 4495void * 4496allocate_module_tls(int index) 4497{ 4498 Obj_Entry* obj; 4499 char* p; 4500 4501 for (obj = obj_list; obj; obj = obj->next) { 4502 if (obj->tlsindex == index) 4503 break; 4504 } 4505 if (!obj) { 4506 _rtld_error("Can't find module with TLS index %d", index); 4507 rtld_die(); 4508 } 4509 4510 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4511 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4512 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4513 4514 return p; 4515} 4516 4517bool 4518allocate_tls_offset(Obj_Entry *obj) 4519{ 4520 size_t off; 4521 4522 if (obj->tls_done) 4523 return true; 4524 4525 if (obj->tlssize == 0) { 4526 obj->tls_done = true; 4527 return true; 4528 } 4529 4530 if (obj->tlsindex == 1) 4531 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4532 else 4533 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4534 obj->tlssize, obj->tlsalign); 4535 4536 /* 4537 * If we have already fixed the size of the static TLS block, we 4538 * must stay within that size. When allocating the static TLS, we 4539 * leave a small amount of space spare to be used for dynamically 4540 * loading modules which use static TLS. 4541 */ 4542 if (tls_static_space != 0) { 4543 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4544 return false; 4545 } else if (obj->tlsalign > tls_static_max_align) { 4546 tls_static_max_align = obj->tlsalign; 4547 } 4548 4549 tls_last_offset = obj->tlsoffset = off; 4550 tls_last_size = obj->tlssize; 4551 obj->tls_done = true; 4552 4553 return true; 4554} 4555 4556void 4557free_tls_offset(Obj_Entry *obj) 4558{ 4559 4560 /* 4561 * If we were the last thing to allocate out of the static TLS 4562 * block, we give our space back to the 'allocator'. This is a 4563 * simplistic workaround to allow libGL.so.1 to be loaded and 4564 * unloaded multiple times. 4565 */ 4566 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4567 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4568 tls_last_offset -= obj->tlssize; 4569 tls_last_size = 0; 4570 } 4571} 4572 4573void * 4574_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4575{ 4576 void *ret; 4577 RtldLockState lockstate; 4578 4579 wlock_acquire(rtld_bind_lock, &lockstate); 4580 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4581 lock_release(rtld_bind_lock, &lockstate); 4582 return (ret); 4583} 4584 4585void 4586_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4587{ 4588 RtldLockState lockstate; 4589 4590 wlock_acquire(rtld_bind_lock, &lockstate); 4591 free_tls(tcb, tcbsize, tcbalign); 4592 lock_release(rtld_bind_lock, &lockstate); 4593} 4594 4595static void 4596object_add_name(Obj_Entry *obj, const char *name) 4597{ 4598 Name_Entry *entry; 4599 size_t len; 4600 4601 len = strlen(name); 4602 entry = malloc(sizeof(Name_Entry) + len); 4603 4604 if (entry != NULL) { 4605 strcpy(entry->name, name); 4606 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4607 } 4608} 4609 4610static int 4611object_match_name(const Obj_Entry *obj, const char *name) 4612{ 4613 Name_Entry *entry; 4614 4615 STAILQ_FOREACH(entry, &obj->names, link) { 4616 if (strcmp(name, entry->name) == 0) 4617 return (1); 4618 } 4619 return (0); 4620} 4621 4622static Obj_Entry * 4623locate_dependency(const Obj_Entry *obj, const char *name) 4624{ 4625 const Objlist_Entry *entry; 4626 const Needed_Entry *needed; 4627 4628 STAILQ_FOREACH(entry, &list_main, link) { 4629 if (object_match_name(entry->obj, name)) 4630 return entry->obj; 4631 } 4632 4633 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4634 if (strcmp(obj->strtab + needed->name, name) == 0 || 4635 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4636 /* 4637 * If there is DT_NEEDED for the name we are looking for, 4638 * we are all set. Note that object might not be found if 4639 * dependency was not loaded yet, so the function can 4640 * return NULL here. This is expected and handled 4641 * properly by the caller. 4642 */ 4643 return (needed->obj); 4644 } 4645 } 4646 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4647 obj->path, name); 4648 rtld_die(); 4649} 4650 4651static int 4652check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4653 const Elf_Vernaux *vna) 4654{ 4655 const Elf_Verdef *vd; 4656 const char *vername; 4657 4658 vername = refobj->strtab + vna->vna_name; 4659 vd = depobj->verdef; 4660 if (vd == NULL) { 4661 _rtld_error("%s: version %s required by %s not defined", 4662 depobj->path, vername, refobj->path); 4663 return (-1); 4664 } 4665 for (;;) { 4666 if (vd->vd_version != VER_DEF_CURRENT) { 4667 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4668 depobj->path, vd->vd_version); 4669 return (-1); 4670 } 4671 if (vna->vna_hash == vd->vd_hash) { 4672 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4673 ((char *)vd + vd->vd_aux); 4674 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4675 return (0); 4676 } 4677 if (vd->vd_next == 0) 4678 break; 4679 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4680 } 4681 if (vna->vna_flags & VER_FLG_WEAK) 4682 return (0); 4683 _rtld_error("%s: version %s required by %s not found", 4684 depobj->path, vername, refobj->path); 4685 return (-1); 4686} 4687 4688static int 4689rtld_verify_object_versions(Obj_Entry *obj) 4690{ 4691 const Elf_Verneed *vn; 4692 const Elf_Verdef *vd; 4693 const Elf_Verdaux *vda; 4694 const Elf_Vernaux *vna; 4695 const Obj_Entry *depobj; 4696 int maxvernum, vernum; 4697 4698 if (obj->ver_checked) 4699 return (0); 4700 obj->ver_checked = true; 4701 4702 maxvernum = 0; 4703 /* 4704 * Walk over defined and required version records and figure out 4705 * max index used by any of them. Do very basic sanity checking 4706 * while there. 4707 */ 4708 vn = obj->verneed; 4709 while (vn != NULL) { 4710 if (vn->vn_version != VER_NEED_CURRENT) { 4711 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4712 obj->path, vn->vn_version); 4713 return (-1); 4714 } 4715 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4716 for (;;) { 4717 vernum = VER_NEED_IDX(vna->vna_other); 4718 if (vernum > maxvernum) 4719 maxvernum = vernum; 4720 if (vna->vna_next == 0) 4721 break; 4722 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4723 } 4724 if (vn->vn_next == 0) 4725 break; 4726 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4727 } 4728 4729 vd = obj->verdef; 4730 while (vd != NULL) { 4731 if (vd->vd_version != VER_DEF_CURRENT) { 4732 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4733 obj->path, vd->vd_version); 4734 return (-1); 4735 } 4736 vernum = VER_DEF_IDX(vd->vd_ndx); 4737 if (vernum > maxvernum) 4738 maxvernum = vernum; 4739 if (vd->vd_next == 0) 4740 break; 4741 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4742 } 4743 4744 if (maxvernum == 0) 4745 return (0); 4746 4747 /* 4748 * Store version information in array indexable by version index. 4749 * Verify that object version requirements are satisfied along the 4750 * way. 4751 */ 4752 obj->vernum = maxvernum + 1; 4753 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4754 4755 vd = obj->verdef; 4756 while (vd != NULL) { 4757 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4758 vernum = VER_DEF_IDX(vd->vd_ndx); 4759 assert(vernum <= maxvernum); 4760 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4761 obj->vertab[vernum].hash = vd->vd_hash; 4762 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4763 obj->vertab[vernum].file = NULL; 4764 obj->vertab[vernum].flags = 0; 4765 } 4766 if (vd->vd_next == 0) 4767 break; 4768 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4769 } 4770 4771 vn = obj->verneed; 4772 while (vn != NULL) { 4773 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4774 if (depobj == NULL) 4775 return (-1); 4776 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4777 for (;;) { 4778 if (check_object_provided_version(obj, depobj, vna)) 4779 return (-1); 4780 vernum = VER_NEED_IDX(vna->vna_other); 4781 assert(vernum <= maxvernum); 4782 obj->vertab[vernum].hash = vna->vna_hash; 4783 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4784 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4785 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4786 VER_INFO_HIDDEN : 0; 4787 if (vna->vna_next == 0) 4788 break; 4789 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4790 } 4791 if (vn->vn_next == 0) 4792 break; 4793 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4794 } 4795 return 0; 4796} 4797 4798static int 4799rtld_verify_versions(const Objlist *objlist) 4800{ 4801 Objlist_Entry *entry; 4802 int rc; 4803 4804 rc = 0; 4805 STAILQ_FOREACH(entry, objlist, link) { 4806 /* 4807 * Skip dummy objects or objects that have their version requirements 4808 * already checked. 4809 */ 4810 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4811 continue; 4812 if (rtld_verify_object_versions(entry->obj) == -1) { 4813 rc = -1; 4814 if (ld_tracing == NULL) 4815 break; 4816 } 4817 } 4818 if (rc == 0 || ld_tracing != NULL) 4819 rc = rtld_verify_object_versions(&obj_rtld); 4820 return rc; 4821} 4822 4823const Ver_Entry * 4824fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4825{ 4826 Elf_Versym vernum; 4827 4828 if (obj->vertab) { 4829 vernum = VER_NDX(obj->versyms[symnum]); 4830 if (vernum >= obj->vernum) { 4831 _rtld_error("%s: symbol %s has wrong verneed value %d", 4832 obj->path, obj->strtab + symnum, vernum); 4833 } else if (obj->vertab[vernum].hash != 0) { 4834 return &obj->vertab[vernum]; 4835 } 4836 } 4837 return NULL; 4838} 4839 4840int 4841_rtld_get_stack_prot(void) 4842{ 4843 4844 return (stack_prot); 4845} 4846 4847int 4848_rtld_is_dlopened(void *arg) 4849{ 4850 Obj_Entry *obj; 4851 RtldLockState lockstate; 4852 int res; 4853 4854 rlock_acquire(rtld_bind_lock, &lockstate); 4855 obj = dlcheck(arg); 4856 if (obj == NULL) 4857 obj = obj_from_addr(arg); 4858 if (obj == NULL) { 4859 _rtld_error("No shared object contains address"); 4860 lock_release(rtld_bind_lock, &lockstate); 4861 return (-1); 4862 } 4863 res = obj->dlopened ? 1 : 0; 4864 lock_release(rtld_bind_lock, &lockstate); 4865 return (res); 4866} 4867 4868static void 4869map_stacks_exec(RtldLockState *lockstate) 4870{ 4871 void (*thr_map_stacks_exec)(void); 4872 4873 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4874 return; 4875 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4876 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4877 if (thr_map_stacks_exec != NULL) { 4878 stack_prot |= PROT_EXEC; 4879 thr_map_stacks_exec(); 4880 } 4881} 4882 4883void 4884symlook_init(SymLook *dst, const char *name) 4885{ 4886 4887 bzero(dst, sizeof(*dst)); 4888 dst->name = name; 4889 dst->hash = elf_hash(name); 4890 dst->hash_gnu = gnu_hash(name); 4891} 4892 4893static void 4894symlook_init_from_req(SymLook *dst, const SymLook *src) 4895{ 4896 4897 dst->name = src->name; 4898 dst->hash = src->hash; 4899 dst->hash_gnu = src->hash_gnu; 4900 dst->ventry = src->ventry; 4901 dst->flags = src->flags; 4902 dst->defobj_out = NULL; 4903 dst->sym_out = NULL; 4904 dst->lockstate = src->lockstate; 4905} 4906 4907/* 4908 * Overrides for libc_pic-provided functions. 4909 */ 4910 4911int 4912__getosreldate(void) 4913{ 4914 size_t len; 4915 int oid[2]; 4916 int error, osrel; 4917 4918 if (osreldate != 0) 4919 return (osreldate); 4920 4921 oid[0] = CTL_KERN; 4922 oid[1] = KERN_OSRELDATE; 4923 osrel = 0; 4924 len = sizeof(osrel); 4925 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4926 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4927 osreldate = osrel; 4928 return (osreldate); 4929} 4930 4931void 4932exit(int status) 4933{ 4934 4935 _exit(status); 4936} 4937 4938void (*__cleanup)(void); 4939int __isthreaded = 0; 4940int _thread_autoinit_dummy_decl = 1; 4941 4942/* 4943 * No unresolved symbols for rtld. 4944 */ 4945void 4946__pthread_cxa_finalize(struct dl_phdr_info *a) 4947{ 4948} 4949 4950void 4951__stack_chk_fail(void) 4952{ 4953 4954 _rtld_error("stack overflow detected; terminated"); 4955 rtld_die(); 4956} 4957__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4958 4959void 4960__chk_fail(void) 4961{ 4962 4963 _rtld_error("buffer overflow detected; terminated"); 4964 rtld_die(); 4965} 4966 4967const char * 4968rtld_strerror(int errnum) 4969{ 4970 4971 if (errnum < 0 || errnum >= sys_nerr) 4972 return ("Unknown error"); 4973 return (sys_errlist[errnum]); 4974} 4975