rtld.c revision 281849
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 281849 2015-04-22 10:59:05Z 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 die(void) __dead2; 82static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 83 const Elf_Dyn **, const Elf_Dyn **); 84static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 85 const Elf_Dyn *); 86static void digest_dynamic(Obj_Entry *, int); 87static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 88static Obj_Entry *dlcheck(void *); 89static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 90 int lo_flags, int mode, RtldLockState *lockstate); 91static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 92static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 93static bool donelist_check(DoneList *, const Obj_Entry *); 94static void errmsg_restore(char *); 95static char *errmsg_save(void); 96static void *fill_search_info(const char *, size_t, void *); 97static char *find_library(const char *, const Obj_Entry *); 98static const char *gethints(bool); 99static void init_dag(Obj_Entry *); 100static void init_pagesizes(Elf_Auxinfo **aux_info); 101static void init_rtld(caddr_t, Elf_Auxinfo **); 102static void initlist_add_neededs(Needed_Entry *, Objlist *); 103static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 104static void linkmap_add(Obj_Entry *); 105static void linkmap_delete(Obj_Entry *); 106static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107static void unload_filtees(Obj_Entry *); 108static int load_needed_objects(Obj_Entry *, int); 109static int load_preload_objects(void); 110static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111static void map_stacks_exec(RtldLockState *); 112static Obj_Entry *obj_from_addr(const void *); 113static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 114static void objlist_call_init(Objlist *, RtldLockState *); 115static void objlist_clear(Objlist *); 116static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117static void objlist_init(Objlist *); 118static void objlist_push_head(Objlist *, Obj_Entry *); 119static void objlist_push_tail(Objlist *, Obj_Entry *); 120static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 121static void objlist_remove(Objlist *, Obj_Entry *); 122static void *path_enumerate(const char *, path_enum_proc, void *); 123static int relocate_object_dag(Obj_Entry *root, bool bind_now, 124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 125static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 126 int flags, RtldLockState *lockstate); 127static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 128 RtldLockState *); 129static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 130 int flags, RtldLockState *lockstate); 131static int rtld_dirname(const char *, char *); 132static int rtld_dirname_abs(const char *, char *); 133static void *rtld_dlopen(const char *name, int fd, int mode); 134static void rtld_exit(void); 135static char *search_library_path(const char *, const char *); 136static const void **get_program_var_addr(const char *, RtldLockState *); 137static void set_program_var(const char *, const void *); 138static int symlook_default(SymLook *, const Obj_Entry *refobj); 139static int symlook_global(SymLook *, DoneList *); 140static void symlook_init_from_req(SymLook *, const SymLook *); 141static int symlook_list(SymLook *, const Objlist *, DoneList *); 142static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 143static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 144static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 145static void trace_loaded_objects(Obj_Entry *); 146static void unlink_object(Obj_Entry *); 147static void unload_object(Obj_Entry *); 148static void unref_dag(Obj_Entry *); 149static void ref_dag(Obj_Entry *); 150static char *origin_subst_one(char *, const char *, const char *, bool); 151static char *origin_subst(char *, const char *); 152static void preinit_main(void); 153static int rtld_verify_versions(const Objlist *); 154static int rtld_verify_object_versions(Obj_Entry *); 155static void object_add_name(Obj_Entry *, const char *); 156static int object_match_name(const Obj_Entry *, const char *); 157static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 158static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 159 struct dl_phdr_info *phdr_info); 160static uint32_t gnu_hash(const char *); 161static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 162 const unsigned long); 163 164void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 165void _r_debug_postinit(struct link_map *) __noinline __exported; 166 167/* 168 * Data declarations. 169 */ 170static char *error_message; /* Message for dlerror(), or NULL */ 171struct r_debug r_debug __exported; /* for GDB; */ 172static bool libmap_disable; /* Disable libmap */ 173static bool ld_loadfltr; /* Immediate filters processing */ 174static char *libmap_override; /* Maps to use in addition to libmap.conf */ 175static bool trust; /* False for setuid and setgid programs */ 176static bool dangerous_ld_env; /* True if environment variables have been 177 used to affect the libraries loaded */ 178static char *ld_bind_now; /* Environment variable for immediate binding */ 179static char *ld_debug; /* Environment variable for debugging */ 180static char *ld_library_path; /* Environment variable for search path */ 181static char *ld_preload; /* Environment variable for libraries to 182 load first */ 183static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 184static char *ld_tracing; /* Called from ldd to print libs */ 185static char *ld_utrace; /* Use utrace() to log events. */ 186static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 187static Obj_Entry **obj_tail; /* Link field of last object in list */ 188static Obj_Entry *obj_main; /* The main program shared object */ 189static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 190static unsigned int obj_count; /* Number of objects in obj_list */ 191static unsigned int obj_loads; /* Number of objects in obj_list */ 192 193static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 194 STAILQ_HEAD_INITIALIZER(list_global); 195static Objlist list_main = /* Objects loaded at program startup */ 196 STAILQ_HEAD_INITIALIZER(list_main); 197static Objlist list_fini = /* Objects needing fini() calls */ 198 STAILQ_HEAD_INITIALIZER(list_fini); 199 200Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 201 202#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 203 204extern Elf_Dyn _DYNAMIC; 205#pragma weak _DYNAMIC 206#ifndef RTLD_IS_DYNAMIC 207#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 208#endif 209 210int dlclose(void *) __exported; 211char *dlerror(void) __exported; 212void *dlopen(const char *, int) __exported; 213void *fdlopen(int, int) __exported; 214void *dlsym(void *, const char *) __exported; 215dlfunc_t dlfunc(void *, const char *) __exported; 216void *dlvsym(void *, const char *, const char *) __exported; 217int dladdr(const void *, Dl_info *) __exported; 218void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 219 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 220int dlinfo(void *, int , void *) __exported; 221int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 222int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 223int _rtld_get_stack_prot(void) __exported; 224int _rtld_is_dlopened(void *) __exported; 225void _rtld_error(const char *, ...) __exported; 226 227int npagesizes, osreldate; 228size_t *pagesizes; 229 230long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 231 232static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 233static int max_stack_flags; 234 235/* 236 * Global declarations normally provided by crt1. The dynamic linker is 237 * not built with crt1, so we have to provide them ourselves. 238 */ 239char *__progname; 240char **environ; 241 242/* 243 * Used to pass argc, argv to init functions. 244 */ 245int main_argc; 246char **main_argv; 247 248/* 249 * Globals to control TLS allocation. 250 */ 251size_t tls_last_offset; /* Static TLS offset of last module */ 252size_t tls_last_size; /* Static TLS size of last module */ 253size_t tls_static_space; /* Static TLS space allocated */ 254size_t tls_static_max_align; 255int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 256int tls_max_index = 1; /* Largest module index allocated */ 257 258bool ld_library_path_rpath = false; 259 260/* 261 * Fill in a DoneList with an allocation large enough to hold all of 262 * the currently-loaded objects. Keep this as a macro since it calls 263 * alloca and we want that to occur within the scope of the caller. 264 */ 265#define donelist_init(dlp) \ 266 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 267 assert((dlp)->objs != NULL), \ 268 (dlp)->num_alloc = obj_count, \ 269 (dlp)->num_used = 0) 270 271#define UTRACE_DLOPEN_START 1 272#define UTRACE_DLOPEN_STOP 2 273#define UTRACE_DLCLOSE_START 3 274#define UTRACE_DLCLOSE_STOP 4 275#define UTRACE_LOAD_OBJECT 5 276#define UTRACE_UNLOAD_OBJECT 6 277#define UTRACE_ADD_RUNDEP 7 278#define UTRACE_PRELOAD_FINISHED 8 279#define UTRACE_INIT_CALL 9 280#define UTRACE_FINI_CALL 10 281 282struct utrace_rtld { 283 char sig[4]; /* 'RTLD' */ 284 int event; 285 void *handle; 286 void *mapbase; /* Used for 'parent' and 'init/fini' */ 287 size_t mapsize; 288 int refcnt; /* Used for 'mode' */ 289 char name[MAXPATHLEN]; 290}; 291 292#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 293 if (ld_utrace != NULL) \ 294 ld_utrace_log(e, h, mb, ms, r, n); \ 295} while (0) 296 297static void 298ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 299 int refcnt, const char *name) 300{ 301 struct utrace_rtld ut; 302 303 ut.sig[0] = 'R'; 304 ut.sig[1] = 'T'; 305 ut.sig[2] = 'L'; 306 ut.sig[3] = 'D'; 307 ut.event = event; 308 ut.handle = handle; 309 ut.mapbase = mapbase; 310 ut.mapsize = mapsize; 311 ut.refcnt = refcnt; 312 bzero(ut.name, sizeof(ut.name)); 313 if (name) 314 strlcpy(ut.name, name, sizeof(ut.name)); 315 utrace(&ut, sizeof(ut)); 316} 317 318/* 319 * Main entry point for dynamic linking. The first argument is the 320 * stack pointer. The stack is expected to be laid out as described 321 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 322 * Specifically, the stack pointer points to a word containing 323 * ARGC. Following that in the stack is a null-terminated sequence 324 * of pointers to argument strings. Then comes a null-terminated 325 * sequence of pointers to environment strings. Finally, there is a 326 * sequence of "auxiliary vector" entries. 327 * 328 * The second argument points to a place to store the dynamic linker's 329 * exit procedure pointer and the third to a place to store the main 330 * program's object. 331 * 332 * The return value is the main program's entry point. 333 */ 334func_ptr_type 335_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 336{ 337 Elf_Auxinfo *aux_info[AT_COUNT]; 338 int i; 339 int argc; 340 char **argv; 341 char **env; 342 Elf_Auxinfo *aux; 343 Elf_Auxinfo *auxp; 344 const char *argv0; 345 Objlist_Entry *entry; 346 Obj_Entry *obj; 347 Obj_Entry **preload_tail; 348 Obj_Entry *last_interposer; 349 Objlist initlist; 350 RtldLockState lockstate; 351 char *library_path_rpath; 352 int mib[2]; 353 size_t len; 354 355 /* 356 * On entry, the dynamic linker itself has not been relocated yet. 357 * Be very careful not to reference any global data until after 358 * init_rtld has returned. It is OK to reference file-scope statics 359 * and string constants, and to call static and global functions. 360 */ 361 362 /* Find the auxiliary vector on the stack. */ 363 argc = *sp++; 364 argv = (char **) sp; 365 sp += argc + 1; /* Skip over arguments and NULL terminator */ 366 env = (char **) sp; 367 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 368 ; 369 aux = (Elf_Auxinfo *) sp; 370 371 /* Digest the auxiliary vector. */ 372 for (i = 0; i < AT_COUNT; i++) 373 aux_info[i] = NULL; 374 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 375 if (auxp->a_type < AT_COUNT) 376 aux_info[auxp->a_type] = auxp; 377 } 378 379 /* Initialize and relocate ourselves. */ 380 assert(aux_info[AT_BASE] != NULL); 381 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 382 383 __progname = obj_rtld.path; 384 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 385 environ = env; 386 main_argc = argc; 387 main_argv = argv; 388 389 if (aux_info[AT_CANARY] != NULL && 390 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 391 i = aux_info[AT_CANARYLEN]->a_un.a_val; 392 if (i > sizeof(__stack_chk_guard)) 393 i = sizeof(__stack_chk_guard); 394 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 395 } else { 396 mib[0] = CTL_KERN; 397 mib[1] = KERN_ARND; 398 399 len = sizeof(__stack_chk_guard); 400 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 401 len != sizeof(__stack_chk_guard)) { 402 /* If sysctl was unsuccessful, use the "terminator canary". */ 403 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 404 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 405 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 406 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 407 } 408 } 409 410 trust = !issetugid(); 411 412 ld_bind_now = getenv(LD_ "BIND_NOW"); 413 /* 414 * If the process is tainted, then we un-set the dangerous environment 415 * variables. The process will be marked as tainted until setuid(2) 416 * is called. If any child process calls setuid(2) we do not want any 417 * future processes to honor the potentially un-safe variables. 418 */ 419 if (!trust) { 420 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 421 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 422 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 423 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 424 _rtld_error("environment corrupt; aborting"); 425 die(); 426 } 427 } 428 ld_debug = getenv(LD_ "DEBUG"); 429 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 430 libmap_override = getenv(LD_ "LIBMAP"); 431 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 432 ld_preload = getenv(LD_ "PRELOAD"); 433 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 434 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 435 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 436 if (library_path_rpath != NULL) { 437 if (library_path_rpath[0] == 'y' || 438 library_path_rpath[0] == 'Y' || 439 library_path_rpath[0] == '1') 440 ld_library_path_rpath = true; 441 else 442 ld_library_path_rpath = false; 443 } 444 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 445 (ld_library_path != NULL) || (ld_preload != NULL) || 446 (ld_elf_hints_path != NULL) || ld_loadfltr; 447 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 448 ld_utrace = getenv(LD_ "UTRACE"); 449 450 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 451 ld_elf_hints_path = _PATH_ELF_HINTS; 452 453 if (ld_debug != NULL && *ld_debug != '\0') 454 debug = 1; 455 dbg("%s is initialized, base address = %p", __progname, 456 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 457 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 458 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 459 460 dbg("initializing thread locks"); 461 lockdflt_init(); 462 463 /* 464 * Load the main program, or process its program header if it is 465 * already loaded. 466 */ 467 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 468 int fd = aux_info[AT_EXECFD]->a_un.a_val; 469 dbg("loading main program"); 470 obj_main = map_object(fd, argv0, NULL); 471 close(fd); 472 if (obj_main == NULL) 473 die(); 474 max_stack_flags = obj->stack_flags; 475 } else { /* Main program already loaded. */ 476 const Elf_Phdr *phdr; 477 int phnum; 478 caddr_t entry; 479 480 dbg("processing main program's program header"); 481 assert(aux_info[AT_PHDR] != NULL); 482 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 483 assert(aux_info[AT_PHNUM] != NULL); 484 phnum = aux_info[AT_PHNUM]->a_un.a_val; 485 assert(aux_info[AT_PHENT] != NULL); 486 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 487 assert(aux_info[AT_ENTRY] != NULL); 488 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 489 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 490 die(); 491 } 492 493 if (aux_info[AT_EXECPATH] != 0) { 494 char *kexecpath; 495 char buf[MAXPATHLEN]; 496 497 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 498 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 499 if (kexecpath[0] == '/') 500 obj_main->path = kexecpath; 501 else if (getcwd(buf, sizeof(buf)) == NULL || 502 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 503 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 504 obj_main->path = xstrdup(argv0); 505 else 506 obj_main->path = xstrdup(buf); 507 } else { 508 dbg("No AT_EXECPATH"); 509 obj_main->path = xstrdup(argv0); 510 } 511 dbg("obj_main path %s", obj_main->path); 512 obj_main->mainprog = true; 513 514 if (aux_info[AT_STACKPROT] != NULL && 515 aux_info[AT_STACKPROT]->a_un.a_val != 0) 516 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 517 518#ifndef COMPAT_32BIT 519 /* 520 * Get the actual dynamic linker pathname from the executable if 521 * possible. (It should always be possible.) That ensures that 522 * gdb will find the right dynamic linker even if a non-standard 523 * one is being used. 524 */ 525 if (obj_main->interp != NULL && 526 strcmp(obj_main->interp, obj_rtld.path) != 0) { 527 free(obj_rtld.path); 528 obj_rtld.path = xstrdup(obj_main->interp); 529 __progname = obj_rtld.path; 530 } 531#endif 532 533 digest_dynamic(obj_main, 0); 534 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 535 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 536 obj_main->dynsymcount); 537 538 linkmap_add(obj_main); 539 linkmap_add(&obj_rtld); 540 541 /* Link the main program into the list of objects. */ 542 *obj_tail = obj_main; 543 obj_tail = &obj_main->next; 544 obj_count++; 545 obj_loads++; 546 547 /* Initialize a fake symbol for resolving undefined weak references. */ 548 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 549 sym_zero.st_shndx = SHN_UNDEF; 550 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 551 552 if (!libmap_disable) 553 libmap_disable = (bool)lm_init(libmap_override); 554 555 dbg("loading LD_PRELOAD libraries"); 556 if (load_preload_objects() == -1) 557 die(); 558 preload_tail = obj_tail; 559 560 dbg("loading needed objects"); 561 if (load_needed_objects(obj_main, 0) == -1) 562 die(); 563 564 /* Make a list of all objects loaded at startup. */ 565 last_interposer = obj_main; 566 for (obj = obj_list; obj != NULL; obj = obj->next) { 567 if (obj->z_interpose && obj != obj_main) { 568 objlist_put_after(&list_main, last_interposer, obj); 569 last_interposer = obj; 570 } else { 571 objlist_push_tail(&list_main, obj); 572 } 573 obj->refcount++; 574 } 575 576 dbg("checking for required versions"); 577 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 578 die(); 579 580 if (ld_tracing) { /* We're done */ 581 trace_loaded_objects(obj_main); 582 exit(0); 583 } 584 585 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 586 dump_relocations(obj_main); 587 exit (0); 588 } 589 590 /* 591 * Processing tls relocations requires having the tls offsets 592 * initialized. Prepare offsets before starting initial 593 * relocation processing. 594 */ 595 dbg("initializing initial thread local storage offsets"); 596 STAILQ_FOREACH(entry, &list_main, link) { 597 /* 598 * Allocate all the initial objects out of the static TLS 599 * block even if they didn't ask for it. 600 */ 601 allocate_tls_offset(entry->obj); 602 } 603 604 if (relocate_objects(obj_main, 605 ld_bind_now != NULL && *ld_bind_now != '\0', 606 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 607 die(); 608 609 dbg("doing copy relocations"); 610 if (do_copy_relocations(obj_main) == -1) 611 die(); 612 613 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 614 dump_relocations(obj_main); 615 exit (0); 616 } 617 618 /* 619 * Setup TLS for main thread. This must be done after the 620 * relocations are processed, since tls initialization section 621 * might be the subject for relocations. 622 */ 623 dbg("initializing initial thread local storage"); 624 allocate_initial_tls(obj_list); 625 626 dbg("initializing key program variables"); 627 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 628 set_program_var("environ", env); 629 set_program_var("__elf_aux_vector", aux); 630 631 /* Make a list of init functions to call. */ 632 objlist_init(&initlist); 633 initlist_add_objects(obj_list, preload_tail, &initlist); 634 635 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 636 637 map_stacks_exec(NULL); 638 639 dbg("resolving ifuncs"); 640 if (resolve_objects_ifunc(obj_main, 641 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 642 NULL) == -1) 643 die(); 644 645 if (!obj_main->crt_no_init) { 646 /* 647 * Make sure we don't call the main program's init and fini 648 * functions for binaries linked with old crt1 which calls 649 * _init itself. 650 */ 651 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 652 obj_main->preinit_array = obj_main->init_array = 653 obj_main->fini_array = (Elf_Addr)NULL; 654 } 655 656 wlock_acquire(rtld_bind_lock, &lockstate); 657 if (obj_main->crt_no_init) 658 preinit_main(); 659 objlist_call_init(&initlist, &lockstate); 660 _r_debug_postinit(&obj_main->linkmap); 661 objlist_clear(&initlist); 662 dbg("loading filtees"); 663 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 664 if (ld_loadfltr || obj->z_loadfltr) 665 load_filtees(obj, 0, &lockstate); 666 } 667 lock_release(rtld_bind_lock, &lockstate); 668 669 dbg("transferring control to program entry point = %p", obj_main->entry); 670 671 /* Return the exit procedure and the program entry point. */ 672 *exit_proc = rtld_exit; 673 *objp = obj_main; 674 return (func_ptr_type) obj_main->entry; 675} 676 677void * 678rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 679{ 680 void *ptr; 681 Elf_Addr target; 682 683 ptr = (void *)make_function_pointer(def, obj); 684 target = ((Elf_Addr (*)(void))ptr)(); 685 return ((void *)target); 686} 687 688Elf_Addr 689_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 690{ 691 const Elf_Rel *rel; 692 const Elf_Sym *def; 693 const Obj_Entry *defobj; 694 Elf_Addr *where; 695 Elf_Addr target; 696 RtldLockState lockstate; 697 698 rlock_acquire(rtld_bind_lock, &lockstate); 699 if (sigsetjmp(lockstate.env, 0) != 0) 700 lock_upgrade(rtld_bind_lock, &lockstate); 701 if (obj->pltrel) 702 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 703 else 704 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 705 706 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 707 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 708 &lockstate); 709 if (def == NULL) 710 die(); 711 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 712 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 713 else 714 target = (Elf_Addr)(defobj->relocbase + def->st_value); 715 716 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 717 defobj->strtab + def->st_name, basename(obj->path), 718 (void *)target, basename(defobj->path)); 719 720 /* 721 * Write the new contents for the jmpslot. Note that depending on 722 * architecture, the value which we need to return back to the 723 * lazy binding trampoline may or may not be the target 724 * address. The value returned from reloc_jmpslot() is the value 725 * that the trampoline needs. 726 */ 727 target = reloc_jmpslot(where, target, defobj, obj, rel); 728 lock_release(rtld_bind_lock, &lockstate); 729 return target; 730} 731 732/* 733 * Error reporting function. Use it like printf. If formats the message 734 * into a buffer, and sets things up so that the next call to dlerror() 735 * will return the message. 736 */ 737void 738_rtld_error(const char *fmt, ...) 739{ 740 static char buf[512]; 741 va_list ap; 742 743 va_start(ap, fmt); 744 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 745 error_message = buf; 746 va_end(ap); 747} 748 749/* 750 * Return a dynamically-allocated copy of the current error message, if any. 751 */ 752static char * 753errmsg_save(void) 754{ 755 return error_message == NULL ? NULL : xstrdup(error_message); 756} 757 758/* 759 * Restore the current error message from a copy which was previously saved 760 * by errmsg_save(). The copy is freed. 761 */ 762static void 763errmsg_restore(char *saved_msg) 764{ 765 if (saved_msg == NULL) 766 error_message = NULL; 767 else { 768 _rtld_error("%s", saved_msg); 769 free(saved_msg); 770 } 771} 772 773static const char * 774basename(const char *name) 775{ 776 const char *p = strrchr(name, '/'); 777 return p != NULL ? p + 1 : name; 778} 779 780static struct utsname uts; 781 782static char * 783origin_subst_one(char *real, const char *kw, const char *subst, 784 bool may_free) 785{ 786 char *p, *p1, *res, *resp; 787 int subst_len, kw_len, subst_count, old_len, new_len; 788 789 kw_len = strlen(kw); 790 791 /* 792 * First, count the number of the keyword occurences, to 793 * preallocate the final string. 794 */ 795 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 796 p1 = strstr(p, kw); 797 if (p1 == NULL) 798 break; 799 } 800 801 /* 802 * If the keyword is not found, just return. 803 */ 804 if (subst_count == 0) 805 return (may_free ? real : xstrdup(real)); 806 807 /* 808 * There is indeed something to substitute. Calculate the 809 * length of the resulting string, and allocate it. 810 */ 811 subst_len = strlen(subst); 812 old_len = strlen(real); 813 new_len = old_len + (subst_len - kw_len) * subst_count; 814 res = xmalloc(new_len + 1); 815 816 /* 817 * Now, execute the substitution loop. 818 */ 819 for (p = real, resp = res, *resp = '\0';;) { 820 p1 = strstr(p, kw); 821 if (p1 != NULL) { 822 /* Copy the prefix before keyword. */ 823 memcpy(resp, p, p1 - p); 824 resp += p1 - p; 825 /* Keyword replacement. */ 826 memcpy(resp, subst, subst_len); 827 resp += subst_len; 828 *resp = '\0'; 829 p = p1 + kw_len; 830 } else 831 break; 832 } 833 834 /* Copy to the end of string and finish. */ 835 strcat(resp, p); 836 if (may_free) 837 free(real); 838 return (res); 839} 840 841static char * 842origin_subst(char *real, const char *origin_path) 843{ 844 char *res1, *res2, *res3, *res4; 845 846 if (uts.sysname[0] == '\0') { 847 if (uname(&uts) != 0) { 848 _rtld_error("utsname failed: %d", errno); 849 return (NULL); 850 } 851 } 852 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 853 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 854 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 855 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 856 return (res4); 857} 858 859static void 860die(void) 861{ 862 const char *msg = dlerror(); 863 864 if (msg == NULL) 865 msg = "Fatal error"; 866 rtld_fdputstr(STDERR_FILENO, msg); 867 rtld_fdputchar(STDERR_FILENO, '\n'); 868 _exit(1); 869} 870 871/* 872 * Process a shared object's DYNAMIC section, and save the important 873 * information in its Obj_Entry structure. 874 */ 875static void 876digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 877 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 878{ 879 const Elf_Dyn *dynp; 880 Needed_Entry **needed_tail = &obj->needed; 881 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 882 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 883 const Elf_Hashelt *hashtab; 884 const Elf32_Word *hashval; 885 Elf32_Word bkt, nmaskwords; 886 int bloom_size32; 887 int plttype = DT_REL; 888 889 *dyn_rpath = NULL; 890 *dyn_soname = NULL; 891 *dyn_runpath = NULL; 892 893 obj->bind_now = false; 894 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 895 switch (dynp->d_tag) { 896 897 case DT_REL: 898 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 899 break; 900 901 case DT_RELSZ: 902 obj->relsize = dynp->d_un.d_val; 903 break; 904 905 case DT_RELENT: 906 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 907 break; 908 909 case DT_JMPREL: 910 obj->pltrel = (const Elf_Rel *) 911 (obj->relocbase + dynp->d_un.d_ptr); 912 break; 913 914 case DT_PLTRELSZ: 915 obj->pltrelsize = dynp->d_un.d_val; 916 break; 917 918 case DT_RELA: 919 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 920 break; 921 922 case DT_RELASZ: 923 obj->relasize = dynp->d_un.d_val; 924 break; 925 926 case DT_RELAENT: 927 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 928 break; 929 930 case DT_PLTREL: 931 plttype = dynp->d_un.d_val; 932 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 933 break; 934 935 case DT_SYMTAB: 936 obj->symtab = (const Elf_Sym *) 937 (obj->relocbase + dynp->d_un.d_ptr); 938 break; 939 940 case DT_SYMENT: 941 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 942 break; 943 944 case DT_STRTAB: 945 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 946 break; 947 948 case DT_STRSZ: 949 obj->strsize = dynp->d_un.d_val; 950 break; 951 952 case DT_VERNEED: 953 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 954 dynp->d_un.d_val); 955 break; 956 957 case DT_VERNEEDNUM: 958 obj->verneednum = dynp->d_un.d_val; 959 break; 960 961 case DT_VERDEF: 962 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 963 dynp->d_un.d_val); 964 break; 965 966 case DT_VERDEFNUM: 967 obj->verdefnum = dynp->d_un.d_val; 968 break; 969 970 case DT_VERSYM: 971 obj->versyms = (const Elf_Versym *)(obj->relocbase + 972 dynp->d_un.d_val); 973 break; 974 975 case DT_HASH: 976 { 977 hashtab = (const Elf_Hashelt *)(obj->relocbase + 978 dynp->d_un.d_ptr); 979 obj->nbuckets = hashtab[0]; 980 obj->nchains = hashtab[1]; 981 obj->buckets = hashtab + 2; 982 obj->chains = obj->buckets + obj->nbuckets; 983 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 984 obj->buckets != NULL; 985 } 986 break; 987 988 case DT_GNU_HASH: 989 { 990 hashtab = (const Elf_Hashelt *)(obj->relocbase + 991 dynp->d_un.d_ptr); 992 obj->nbuckets_gnu = hashtab[0]; 993 obj->symndx_gnu = hashtab[1]; 994 nmaskwords = hashtab[2]; 995 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 996 obj->maskwords_bm_gnu = nmaskwords - 1; 997 obj->shift2_gnu = hashtab[3]; 998 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 999 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1000 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1001 obj->symndx_gnu; 1002 /* Number of bitmask words is required to be power of 2 */ 1003 obj->valid_hash_gnu = powerof2(nmaskwords) && 1004 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1005 } 1006 break; 1007 1008 case DT_NEEDED: 1009 if (!obj->rtld) { 1010 Needed_Entry *nep = NEW(Needed_Entry); 1011 nep->name = dynp->d_un.d_val; 1012 nep->obj = NULL; 1013 nep->next = NULL; 1014 1015 *needed_tail = nep; 1016 needed_tail = &nep->next; 1017 } 1018 break; 1019 1020 case DT_FILTER: 1021 if (!obj->rtld) { 1022 Needed_Entry *nep = NEW(Needed_Entry); 1023 nep->name = dynp->d_un.d_val; 1024 nep->obj = NULL; 1025 nep->next = NULL; 1026 1027 *needed_filtees_tail = nep; 1028 needed_filtees_tail = &nep->next; 1029 } 1030 break; 1031 1032 case DT_AUXILIARY: 1033 if (!obj->rtld) { 1034 Needed_Entry *nep = NEW(Needed_Entry); 1035 nep->name = dynp->d_un.d_val; 1036 nep->obj = NULL; 1037 nep->next = NULL; 1038 1039 *needed_aux_filtees_tail = nep; 1040 needed_aux_filtees_tail = &nep->next; 1041 } 1042 break; 1043 1044 case DT_PLTGOT: 1045 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1046 break; 1047 1048 case DT_TEXTREL: 1049 obj->textrel = true; 1050 break; 1051 1052 case DT_SYMBOLIC: 1053 obj->symbolic = true; 1054 break; 1055 1056 case DT_RPATH: 1057 /* 1058 * We have to wait until later to process this, because we 1059 * might not have gotten the address of the string table yet. 1060 */ 1061 *dyn_rpath = dynp; 1062 break; 1063 1064 case DT_SONAME: 1065 *dyn_soname = dynp; 1066 break; 1067 1068 case DT_RUNPATH: 1069 *dyn_runpath = dynp; 1070 break; 1071 1072 case DT_INIT: 1073 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1074 break; 1075 1076 case DT_PREINIT_ARRAY: 1077 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1078 break; 1079 1080 case DT_PREINIT_ARRAYSZ: 1081 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1082 break; 1083 1084 case DT_INIT_ARRAY: 1085 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1086 break; 1087 1088 case DT_INIT_ARRAYSZ: 1089 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1090 break; 1091 1092 case DT_FINI: 1093 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1094 break; 1095 1096 case DT_FINI_ARRAY: 1097 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1098 break; 1099 1100 case DT_FINI_ARRAYSZ: 1101 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1102 break; 1103 1104 /* 1105 * Don't process DT_DEBUG on MIPS as the dynamic section 1106 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1107 */ 1108 1109#ifndef __mips__ 1110 case DT_DEBUG: 1111 /* XXX - not implemented yet */ 1112 if (!early) 1113 dbg("Filling in DT_DEBUG entry"); 1114 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1115 break; 1116#endif 1117 1118 case DT_FLAGS: 1119 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1120 obj->z_origin = true; 1121 if (dynp->d_un.d_val & DF_SYMBOLIC) 1122 obj->symbolic = true; 1123 if (dynp->d_un.d_val & DF_TEXTREL) 1124 obj->textrel = true; 1125 if (dynp->d_un.d_val & DF_BIND_NOW) 1126 obj->bind_now = true; 1127 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1128 ;*/ 1129 break; 1130#ifdef __mips__ 1131 case DT_MIPS_LOCAL_GOTNO: 1132 obj->local_gotno = dynp->d_un.d_val; 1133 break; 1134 1135 case DT_MIPS_SYMTABNO: 1136 obj->symtabno = dynp->d_un.d_val; 1137 break; 1138 1139 case DT_MIPS_GOTSYM: 1140 obj->gotsym = dynp->d_un.d_val; 1141 break; 1142 1143 case DT_MIPS_RLD_MAP: 1144 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1145 break; 1146#endif 1147 1148 case DT_FLAGS_1: 1149 if (dynp->d_un.d_val & DF_1_NOOPEN) 1150 obj->z_noopen = true; 1151 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1152 obj->z_origin = true; 1153 if (dynp->d_un.d_val & DF_1_GLOBAL) 1154 obj->z_global = true; 1155 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1156 obj->bind_now = true; 1157 if (dynp->d_un.d_val & DF_1_NODELETE) 1158 obj->z_nodelete = true; 1159 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1160 obj->z_loadfltr = true; 1161 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1162 obj->z_interpose = true; 1163 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1164 obj->z_nodeflib = true; 1165 break; 1166 1167 default: 1168 if (!early) { 1169 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1170 (long)dynp->d_tag); 1171 } 1172 break; 1173 } 1174 } 1175 1176 obj->traced = false; 1177 1178 if (plttype == DT_RELA) { 1179 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1180 obj->pltrel = NULL; 1181 obj->pltrelasize = obj->pltrelsize; 1182 obj->pltrelsize = 0; 1183 } 1184 1185 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1186 if (obj->valid_hash_sysv) 1187 obj->dynsymcount = obj->nchains; 1188 else if (obj->valid_hash_gnu) { 1189 obj->dynsymcount = 0; 1190 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1191 if (obj->buckets_gnu[bkt] == 0) 1192 continue; 1193 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1194 do 1195 obj->dynsymcount++; 1196 while ((*hashval++ & 1u) == 0); 1197 } 1198 obj->dynsymcount += obj->symndx_gnu; 1199 } 1200} 1201 1202static void 1203digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1204 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1205{ 1206 1207 if (obj->z_origin && obj->origin_path == NULL) { 1208 obj->origin_path = xmalloc(PATH_MAX); 1209 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1210 die(); 1211 } 1212 1213 if (dyn_runpath != NULL) { 1214 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1215 if (obj->z_origin) 1216 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1217 } 1218 else if (dyn_rpath != NULL) { 1219 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1220 if (obj->z_origin) 1221 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1222 } 1223 1224 if (dyn_soname != NULL) 1225 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1226} 1227 1228static void 1229digest_dynamic(Obj_Entry *obj, int early) 1230{ 1231 const Elf_Dyn *dyn_rpath; 1232 const Elf_Dyn *dyn_soname; 1233 const Elf_Dyn *dyn_runpath; 1234 1235 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1236 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1237} 1238 1239/* 1240 * Process a shared object's program header. This is used only for the 1241 * main program, when the kernel has already loaded the main program 1242 * into memory before calling the dynamic linker. It creates and 1243 * returns an Obj_Entry structure. 1244 */ 1245static Obj_Entry * 1246digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1247{ 1248 Obj_Entry *obj; 1249 const Elf_Phdr *phlimit = phdr + phnum; 1250 const Elf_Phdr *ph; 1251 Elf_Addr note_start, note_end; 1252 int nsegs = 0; 1253 1254 obj = obj_new(); 1255 for (ph = phdr; ph < phlimit; ph++) { 1256 if (ph->p_type != PT_PHDR) 1257 continue; 1258 1259 obj->phdr = phdr; 1260 obj->phsize = ph->p_memsz; 1261 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1262 break; 1263 } 1264 1265 obj->stack_flags = PF_X | PF_R | PF_W; 1266 1267 for (ph = phdr; ph < phlimit; ph++) { 1268 switch (ph->p_type) { 1269 1270 case PT_INTERP: 1271 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1272 break; 1273 1274 case PT_LOAD: 1275 if (nsegs == 0) { /* First load segment */ 1276 obj->vaddrbase = trunc_page(ph->p_vaddr); 1277 obj->mapbase = obj->vaddrbase + obj->relocbase; 1278 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1279 obj->vaddrbase; 1280 } else { /* Last load segment */ 1281 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1282 obj->vaddrbase; 1283 } 1284 nsegs++; 1285 break; 1286 1287 case PT_DYNAMIC: 1288 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1289 break; 1290 1291 case PT_TLS: 1292 obj->tlsindex = 1; 1293 obj->tlssize = ph->p_memsz; 1294 obj->tlsalign = ph->p_align; 1295 obj->tlsinitsize = ph->p_filesz; 1296 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1297 break; 1298 1299 case PT_GNU_STACK: 1300 obj->stack_flags = ph->p_flags; 1301 break; 1302 1303 case PT_GNU_RELRO: 1304 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1305 obj->relro_size = round_page(ph->p_memsz); 1306 break; 1307 1308 case PT_NOTE: 1309 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1310 note_end = note_start + ph->p_filesz; 1311 digest_notes(obj, note_start, note_end); 1312 break; 1313 } 1314 } 1315 if (nsegs < 1) { 1316 _rtld_error("%s: too few PT_LOAD segments", path); 1317 return NULL; 1318 } 1319 1320 obj->entry = entry; 1321 return obj; 1322} 1323 1324void 1325digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1326{ 1327 const Elf_Note *note; 1328 const char *note_name; 1329 uintptr_t p; 1330 1331 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1332 note = (const Elf_Note *)((const char *)(note + 1) + 1333 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1334 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1335 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1336 note->n_descsz != sizeof(int32_t)) 1337 continue; 1338 if (note->n_type != ABI_NOTETYPE && 1339 note->n_type != CRT_NOINIT_NOTETYPE) 1340 continue; 1341 note_name = (const char *)(note + 1); 1342 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1343 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1344 continue; 1345 switch (note->n_type) { 1346 case ABI_NOTETYPE: 1347 /* FreeBSD osrel note */ 1348 p = (uintptr_t)(note + 1); 1349 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1350 obj->osrel = *(const int32_t *)(p); 1351 dbg("note osrel %d", obj->osrel); 1352 break; 1353 case CRT_NOINIT_NOTETYPE: 1354 /* FreeBSD 'crt does not call init' note */ 1355 obj->crt_no_init = true; 1356 dbg("note crt_no_init"); 1357 break; 1358 } 1359 } 1360} 1361 1362static Obj_Entry * 1363dlcheck(void *handle) 1364{ 1365 Obj_Entry *obj; 1366 1367 for (obj = obj_list; obj != NULL; obj = obj->next) 1368 if (obj == (Obj_Entry *) handle) 1369 break; 1370 1371 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1372 _rtld_error("Invalid shared object handle %p", handle); 1373 return NULL; 1374 } 1375 return obj; 1376} 1377 1378/* 1379 * If the given object is already in the donelist, return true. Otherwise 1380 * add the object to the list and return false. 1381 */ 1382static bool 1383donelist_check(DoneList *dlp, const Obj_Entry *obj) 1384{ 1385 unsigned int i; 1386 1387 for (i = 0; i < dlp->num_used; i++) 1388 if (dlp->objs[i] == obj) 1389 return true; 1390 /* 1391 * Our donelist allocation should always be sufficient. But if 1392 * our threads locking isn't working properly, more shared objects 1393 * could have been loaded since we allocated the list. That should 1394 * never happen, but we'll handle it properly just in case it does. 1395 */ 1396 if (dlp->num_used < dlp->num_alloc) 1397 dlp->objs[dlp->num_used++] = obj; 1398 return false; 1399} 1400 1401/* 1402 * Hash function for symbol table lookup. Don't even think about changing 1403 * this. It is specified by the System V ABI. 1404 */ 1405unsigned long 1406elf_hash(const char *name) 1407{ 1408 const unsigned char *p = (const unsigned char *) name; 1409 unsigned long h = 0; 1410 unsigned long g; 1411 1412 while (*p != '\0') { 1413 h = (h << 4) + *p++; 1414 if ((g = h & 0xf0000000) != 0) 1415 h ^= g >> 24; 1416 h &= ~g; 1417 } 1418 return h; 1419} 1420 1421/* 1422 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1423 * unsigned in case it's implemented with a wider type. 1424 */ 1425static uint32_t 1426gnu_hash(const char *s) 1427{ 1428 uint32_t h; 1429 unsigned char c; 1430 1431 h = 5381; 1432 for (c = *s; c != '\0'; c = *++s) 1433 h = h * 33 + c; 1434 return (h & 0xffffffff); 1435} 1436 1437/* 1438 * Find the library with the given name, and return its full pathname. 1439 * The returned string is dynamically allocated. Generates an error 1440 * message and returns NULL if the library cannot be found. 1441 * 1442 * If the second argument is non-NULL, then it refers to an already- 1443 * loaded shared object, whose library search path will be searched. 1444 * 1445 * The search order is: 1446 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1447 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1448 * LD_LIBRARY_PATH 1449 * DT_RUNPATH in the referencing file 1450 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1451 * from list) 1452 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1453 * 1454 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1455 */ 1456static char * 1457find_library(const char *xname, const Obj_Entry *refobj) 1458{ 1459 char *pathname; 1460 char *name; 1461 bool nodeflib, objgiven; 1462 1463 objgiven = refobj != NULL; 1464 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1465 if (xname[0] != '/' && !trust) { 1466 _rtld_error("Absolute pathname required for shared object \"%s\"", 1467 xname); 1468 return NULL; 1469 } 1470 if (objgiven && refobj->z_origin) { 1471 return (origin_subst(__DECONST(char *, xname), 1472 refobj->origin_path)); 1473 } else { 1474 return (xstrdup(xname)); 1475 } 1476 } 1477 1478 if (libmap_disable || !objgiven || 1479 (name = lm_find(refobj->path, xname)) == NULL) 1480 name = (char *)xname; 1481 1482 dbg(" Searching for \"%s\"", name); 1483 1484 /* 1485 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1486 * back to pre-conforming behaviour if user requested so with 1487 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1488 * nodeflib. 1489 */ 1490 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1491 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1492 (refobj != NULL && 1493 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1494 (pathname = search_library_path(name, gethints(false))) != NULL || 1495 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1496 return (pathname); 1497 } else { 1498 nodeflib = objgiven ? refobj->z_nodeflib : false; 1499 if ((objgiven && 1500 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1501 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1502 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1503 (pathname = search_library_path(name, ld_library_path)) != NULL || 1504 (objgiven && 1505 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1506 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1507 (objgiven && !nodeflib && 1508 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1509 return (pathname); 1510 } 1511 1512 if (objgiven && refobj->path != NULL) { 1513 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1514 name, basename(refobj->path)); 1515 } else { 1516 _rtld_error("Shared object \"%s\" not found", name); 1517 } 1518 return NULL; 1519} 1520 1521/* 1522 * Given a symbol number in a referencing object, find the corresponding 1523 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1524 * no definition was found. Returns a pointer to the Obj_Entry of the 1525 * defining object via the reference parameter DEFOBJ_OUT. 1526 */ 1527const Elf_Sym * 1528find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1529 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1530 RtldLockState *lockstate) 1531{ 1532 const Elf_Sym *ref; 1533 const Elf_Sym *def; 1534 const Obj_Entry *defobj; 1535 SymLook req; 1536 const char *name; 1537 int res; 1538 1539 /* 1540 * If we have already found this symbol, get the information from 1541 * the cache. 1542 */ 1543 if (symnum >= refobj->dynsymcount) 1544 return NULL; /* Bad object */ 1545 if (cache != NULL && cache[symnum].sym != NULL) { 1546 *defobj_out = cache[symnum].obj; 1547 return cache[symnum].sym; 1548 } 1549 1550 ref = refobj->symtab + symnum; 1551 name = refobj->strtab + ref->st_name; 1552 def = NULL; 1553 defobj = NULL; 1554 1555 /* 1556 * We don't have to do a full scale lookup if the symbol is local. 1557 * We know it will bind to the instance in this load module; to 1558 * which we already have a pointer (ie ref). By not doing a lookup, 1559 * we not only improve performance, but it also avoids unresolvable 1560 * symbols when local symbols are not in the hash table. This has 1561 * been seen with the ia64 toolchain. 1562 */ 1563 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1564 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1565 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1566 symnum); 1567 } 1568 symlook_init(&req, name); 1569 req.flags = flags; 1570 req.ventry = fetch_ventry(refobj, symnum); 1571 req.lockstate = lockstate; 1572 res = symlook_default(&req, refobj); 1573 if (res == 0) { 1574 def = req.sym_out; 1575 defobj = req.defobj_out; 1576 } 1577 } else { 1578 def = ref; 1579 defobj = refobj; 1580 } 1581 1582 /* 1583 * If we found no definition and the reference is weak, treat the 1584 * symbol as having the value zero. 1585 */ 1586 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1587 def = &sym_zero; 1588 defobj = obj_main; 1589 } 1590 1591 if (def != NULL) { 1592 *defobj_out = defobj; 1593 /* Record the information in the cache to avoid subsequent lookups. */ 1594 if (cache != NULL) { 1595 cache[symnum].sym = def; 1596 cache[symnum].obj = defobj; 1597 } 1598 } else { 1599 if (refobj != &obj_rtld) 1600 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1601 } 1602 return def; 1603} 1604 1605/* 1606 * Return the search path from the ldconfig hints file, reading it if 1607 * necessary. If nostdlib is true, then the default search paths are 1608 * not added to result. 1609 * 1610 * Returns NULL if there are problems with the hints file, 1611 * or if the search path there is empty. 1612 */ 1613static const char * 1614gethints(bool nostdlib) 1615{ 1616 static char *hints, *filtered_path; 1617 struct elfhints_hdr hdr; 1618 struct fill_search_info_args sargs, hargs; 1619 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1620 struct dl_serpath *SLPpath, *hintpath; 1621 char *p; 1622 unsigned int SLPndx, hintndx, fndx, fcount; 1623 int fd; 1624 size_t flen; 1625 bool skip; 1626 1627 /* First call, read the hints file */ 1628 if (hints == NULL) { 1629 /* Keep from trying again in case the hints file is bad. */ 1630 hints = ""; 1631 1632 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1633 return (NULL); 1634 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1635 hdr.magic != ELFHINTS_MAGIC || 1636 hdr.version != 1) { 1637 close(fd); 1638 return (NULL); 1639 } 1640 p = xmalloc(hdr.dirlistlen + 1); 1641 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1642 read(fd, p, hdr.dirlistlen + 1) != 1643 (ssize_t)hdr.dirlistlen + 1) { 1644 free(p); 1645 close(fd); 1646 return (NULL); 1647 } 1648 hints = p; 1649 close(fd); 1650 } 1651 1652 /* 1653 * If caller agreed to receive list which includes the default 1654 * paths, we are done. Otherwise, if we still did not 1655 * calculated filtered result, do it now. 1656 */ 1657 if (!nostdlib) 1658 return (hints[0] != '\0' ? hints : NULL); 1659 if (filtered_path != NULL) 1660 goto filt_ret; 1661 1662 /* 1663 * Obtain the list of all configured search paths, and the 1664 * list of the default paths. 1665 * 1666 * First estimate the size of the results. 1667 */ 1668 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1669 smeta.dls_cnt = 0; 1670 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1671 hmeta.dls_cnt = 0; 1672 1673 sargs.request = RTLD_DI_SERINFOSIZE; 1674 sargs.serinfo = &smeta; 1675 hargs.request = RTLD_DI_SERINFOSIZE; 1676 hargs.serinfo = &hmeta; 1677 1678 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1679 path_enumerate(p, fill_search_info, &hargs); 1680 1681 SLPinfo = xmalloc(smeta.dls_size); 1682 hintinfo = xmalloc(hmeta.dls_size); 1683 1684 /* 1685 * Next fetch both sets of paths. 1686 */ 1687 sargs.request = RTLD_DI_SERINFO; 1688 sargs.serinfo = SLPinfo; 1689 sargs.serpath = &SLPinfo->dls_serpath[0]; 1690 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1691 1692 hargs.request = RTLD_DI_SERINFO; 1693 hargs.serinfo = hintinfo; 1694 hargs.serpath = &hintinfo->dls_serpath[0]; 1695 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1696 1697 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1698 path_enumerate(p, fill_search_info, &hargs); 1699 1700 /* 1701 * Now calculate the difference between two sets, by excluding 1702 * standard paths from the full set. 1703 */ 1704 fndx = 0; 1705 fcount = 0; 1706 filtered_path = xmalloc(hdr.dirlistlen + 1); 1707 hintpath = &hintinfo->dls_serpath[0]; 1708 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1709 skip = false; 1710 SLPpath = &SLPinfo->dls_serpath[0]; 1711 /* 1712 * Check each standard path against current. 1713 */ 1714 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1715 /* matched, skip the path */ 1716 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1717 skip = true; 1718 break; 1719 } 1720 } 1721 if (skip) 1722 continue; 1723 /* 1724 * Not matched against any standard path, add the path 1725 * to result. Separate consequtive paths with ':'. 1726 */ 1727 if (fcount > 0) { 1728 filtered_path[fndx] = ':'; 1729 fndx++; 1730 } 1731 fcount++; 1732 flen = strlen(hintpath->dls_name); 1733 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1734 fndx += flen; 1735 } 1736 filtered_path[fndx] = '\0'; 1737 1738 free(SLPinfo); 1739 free(hintinfo); 1740 1741filt_ret: 1742 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1743} 1744 1745static void 1746init_dag(Obj_Entry *root) 1747{ 1748 const Needed_Entry *needed; 1749 const Objlist_Entry *elm; 1750 DoneList donelist; 1751 1752 if (root->dag_inited) 1753 return; 1754 donelist_init(&donelist); 1755 1756 /* Root object belongs to own DAG. */ 1757 objlist_push_tail(&root->dldags, root); 1758 objlist_push_tail(&root->dagmembers, root); 1759 donelist_check(&donelist, root); 1760 1761 /* 1762 * Add dependencies of root object to DAG in breadth order 1763 * by exploiting the fact that each new object get added 1764 * to the tail of the dagmembers list. 1765 */ 1766 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1767 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1768 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1769 continue; 1770 objlist_push_tail(&needed->obj->dldags, root); 1771 objlist_push_tail(&root->dagmembers, needed->obj); 1772 } 1773 } 1774 root->dag_inited = true; 1775} 1776 1777static void 1778process_z(Obj_Entry *root) 1779{ 1780 const Objlist_Entry *elm; 1781 Obj_Entry *obj; 1782 1783 /* 1784 * Walk over object DAG and process every dependent object 1785 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1786 * to grow their own DAG. 1787 * 1788 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1789 * symlook_global() to work. 1790 * 1791 * For DF_1_NODELETE, the DAG should have its reference upped. 1792 */ 1793 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1794 obj = elm->obj; 1795 if (obj == NULL) 1796 continue; 1797 if (obj->z_nodelete && !obj->ref_nodel) { 1798 dbg("obj %s -z nodelete", obj->path); 1799 init_dag(obj); 1800 ref_dag(obj); 1801 obj->ref_nodel = true; 1802 } 1803 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1804 dbg("obj %s -z global", obj->path); 1805 objlist_push_tail(&list_global, obj); 1806 init_dag(obj); 1807 } 1808 } 1809} 1810/* 1811 * Initialize the dynamic linker. The argument is the address at which 1812 * the dynamic linker has been mapped into memory. The primary task of 1813 * this function is to relocate the dynamic linker. 1814 */ 1815static void 1816init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1817{ 1818 Obj_Entry objtmp; /* Temporary rtld object */ 1819 const Elf_Dyn *dyn_rpath; 1820 const Elf_Dyn *dyn_soname; 1821 const Elf_Dyn *dyn_runpath; 1822 1823#ifdef RTLD_INIT_PAGESIZES_EARLY 1824 /* The page size is required by the dynamic memory allocator. */ 1825 init_pagesizes(aux_info); 1826#endif 1827 1828 /* 1829 * Conjure up an Obj_Entry structure for the dynamic linker. 1830 * 1831 * The "path" member can't be initialized yet because string constants 1832 * cannot yet be accessed. Below we will set it correctly. 1833 */ 1834 memset(&objtmp, 0, sizeof(objtmp)); 1835 objtmp.path = NULL; 1836 objtmp.rtld = true; 1837 objtmp.mapbase = mapbase; 1838#ifdef PIC 1839 objtmp.relocbase = mapbase; 1840#endif 1841 if (RTLD_IS_DYNAMIC()) { 1842 objtmp.dynamic = rtld_dynamic(&objtmp); 1843 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1844 assert(objtmp.needed == NULL); 1845#if !defined(__mips__) 1846 /* MIPS has a bogus DT_TEXTREL. */ 1847 assert(!objtmp.textrel); 1848#endif 1849 1850 /* 1851 * Temporarily put the dynamic linker entry into the object list, so 1852 * that symbols can be found. 1853 */ 1854 1855 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1856 } 1857 1858 /* Initialize the object list. */ 1859 obj_tail = &obj_list; 1860 1861 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1862 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1863 1864#ifndef RTLD_INIT_PAGESIZES_EARLY 1865 /* The page size is required by the dynamic memory allocator. */ 1866 init_pagesizes(aux_info); 1867#endif 1868 1869 if (aux_info[AT_OSRELDATE] != NULL) 1870 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1871 1872 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1873 1874 /* Replace the path with a dynamically allocated copy. */ 1875 obj_rtld.path = xstrdup(PATH_RTLD); 1876 1877 r_debug.r_brk = r_debug_state; 1878 r_debug.r_state = RT_CONSISTENT; 1879} 1880 1881/* 1882 * Retrieve the array of supported page sizes. The kernel provides the page 1883 * sizes in increasing order. 1884 */ 1885static void 1886init_pagesizes(Elf_Auxinfo **aux_info) 1887{ 1888 static size_t psa[MAXPAGESIZES]; 1889 int mib[2]; 1890 size_t len, size; 1891 1892 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1893 NULL) { 1894 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1895 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1896 } else { 1897 len = 2; 1898 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1899 size = sizeof(psa); 1900 else { 1901 /* As a fallback, retrieve the base page size. */ 1902 size = sizeof(psa[0]); 1903 if (aux_info[AT_PAGESZ] != NULL) { 1904 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1905 goto psa_filled; 1906 } else { 1907 mib[0] = CTL_HW; 1908 mib[1] = HW_PAGESIZE; 1909 len = 2; 1910 } 1911 } 1912 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1913 _rtld_error("sysctl for hw.pagesize(s) failed"); 1914 die(); 1915 } 1916psa_filled: 1917 pagesizes = psa; 1918 } 1919 npagesizes = size / sizeof(pagesizes[0]); 1920 /* Discard any invalid entries at the end of the array. */ 1921 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1922 npagesizes--; 1923} 1924 1925/* 1926 * Add the init functions from a needed object list (and its recursive 1927 * needed objects) to "list". This is not used directly; it is a helper 1928 * function for initlist_add_objects(). The write lock must be held 1929 * when this function is called. 1930 */ 1931static void 1932initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1933{ 1934 /* Recursively process the successor needed objects. */ 1935 if (needed->next != NULL) 1936 initlist_add_neededs(needed->next, list); 1937 1938 /* Process the current needed object. */ 1939 if (needed->obj != NULL) 1940 initlist_add_objects(needed->obj, &needed->obj->next, list); 1941} 1942 1943/* 1944 * Scan all of the DAGs rooted in the range of objects from "obj" to 1945 * "tail" and add their init functions to "list". This recurses over 1946 * the DAGs and ensure the proper init ordering such that each object's 1947 * needed libraries are initialized before the object itself. At the 1948 * same time, this function adds the objects to the global finalization 1949 * list "list_fini" in the opposite order. The write lock must be 1950 * held when this function is called. 1951 */ 1952static void 1953initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1954{ 1955 1956 if (obj->init_scanned || obj->init_done) 1957 return; 1958 obj->init_scanned = true; 1959 1960 /* Recursively process the successor objects. */ 1961 if (&obj->next != tail) 1962 initlist_add_objects(obj->next, tail, list); 1963 1964 /* Recursively process the needed objects. */ 1965 if (obj->needed != NULL) 1966 initlist_add_neededs(obj->needed, list); 1967 if (obj->needed_filtees != NULL) 1968 initlist_add_neededs(obj->needed_filtees, list); 1969 if (obj->needed_aux_filtees != NULL) 1970 initlist_add_neededs(obj->needed_aux_filtees, list); 1971 1972 /* Add the object to the init list. */ 1973 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1974 obj->init_array != (Elf_Addr)NULL) 1975 objlist_push_tail(list, obj); 1976 1977 /* Add the object to the global fini list in the reverse order. */ 1978 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1979 && !obj->on_fini_list) { 1980 objlist_push_head(&list_fini, obj); 1981 obj->on_fini_list = true; 1982 } 1983} 1984 1985#ifndef FPTR_TARGET 1986#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1987#endif 1988 1989static void 1990free_needed_filtees(Needed_Entry *n) 1991{ 1992 Needed_Entry *needed, *needed1; 1993 1994 for (needed = n; needed != NULL; needed = needed->next) { 1995 if (needed->obj != NULL) { 1996 dlclose(needed->obj); 1997 needed->obj = NULL; 1998 } 1999 } 2000 for (needed = n; needed != NULL; needed = needed1) { 2001 needed1 = needed->next; 2002 free(needed); 2003 } 2004} 2005 2006static void 2007unload_filtees(Obj_Entry *obj) 2008{ 2009 2010 free_needed_filtees(obj->needed_filtees); 2011 obj->needed_filtees = NULL; 2012 free_needed_filtees(obj->needed_aux_filtees); 2013 obj->needed_aux_filtees = NULL; 2014 obj->filtees_loaded = false; 2015} 2016 2017static void 2018load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2019 RtldLockState *lockstate) 2020{ 2021 2022 for (; needed != NULL; needed = needed->next) { 2023 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2024 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2025 RTLD_LOCAL, lockstate); 2026 } 2027} 2028 2029static void 2030load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2031{ 2032 2033 lock_restart_for_upgrade(lockstate); 2034 if (!obj->filtees_loaded) { 2035 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2036 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2037 obj->filtees_loaded = true; 2038 } 2039} 2040 2041static int 2042process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2043{ 2044 Obj_Entry *obj1; 2045 2046 for (; needed != NULL; needed = needed->next) { 2047 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2048 flags & ~RTLD_LO_NOLOAD); 2049 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2050 return (-1); 2051 } 2052 return (0); 2053} 2054 2055/* 2056 * Given a shared object, traverse its list of needed objects, and load 2057 * each of them. Returns 0 on success. Generates an error message and 2058 * returns -1 on failure. 2059 */ 2060static int 2061load_needed_objects(Obj_Entry *first, int flags) 2062{ 2063 Obj_Entry *obj; 2064 2065 for (obj = first; obj != NULL; obj = obj->next) { 2066 if (process_needed(obj, obj->needed, flags) == -1) 2067 return (-1); 2068 } 2069 return (0); 2070} 2071 2072static int 2073load_preload_objects(void) 2074{ 2075 char *p = ld_preload; 2076 Obj_Entry *obj; 2077 static const char delim[] = " \t:;"; 2078 2079 if (p == NULL) 2080 return 0; 2081 2082 p += strspn(p, delim); 2083 while (*p != '\0') { 2084 size_t len = strcspn(p, delim); 2085 char savech; 2086 2087 savech = p[len]; 2088 p[len] = '\0'; 2089 obj = load_object(p, -1, NULL, 0); 2090 if (obj == NULL) 2091 return -1; /* XXX - cleanup */ 2092 obj->z_interpose = true; 2093 p[len] = savech; 2094 p += len; 2095 p += strspn(p, delim); 2096 } 2097 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2098 return 0; 2099} 2100 2101static const char * 2102printable_path(const char *path) 2103{ 2104 2105 return (path == NULL ? "<unknown>" : path); 2106} 2107 2108/* 2109 * Load a shared object into memory, if it is not already loaded. The 2110 * object may be specified by name or by user-supplied file descriptor 2111 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2112 * duplicate is. 2113 * 2114 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2115 * on failure. 2116 */ 2117static Obj_Entry * 2118load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2119{ 2120 Obj_Entry *obj; 2121 int fd; 2122 struct stat sb; 2123 char *path; 2124 2125 if (name != NULL) { 2126 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2127 if (object_match_name(obj, name)) 2128 return (obj); 2129 } 2130 2131 path = find_library(name, refobj); 2132 if (path == NULL) 2133 return (NULL); 2134 } else 2135 path = NULL; 2136 2137 /* 2138 * If we didn't find a match by pathname, or the name is not 2139 * supplied, open the file and check again by device and inode. 2140 * This avoids false mismatches caused by multiple links or ".." 2141 * in pathnames. 2142 * 2143 * To avoid a race, we open the file and use fstat() rather than 2144 * using stat(). 2145 */ 2146 fd = -1; 2147 if (fd_u == -1) { 2148 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2149 _rtld_error("Cannot open \"%s\"", path); 2150 free(path); 2151 return (NULL); 2152 } 2153 } else { 2154 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2155 if (fd == -1) { 2156 _rtld_error("Cannot dup fd"); 2157 free(path); 2158 return (NULL); 2159 } 2160 } 2161 if (fstat(fd, &sb) == -1) { 2162 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2163 close(fd); 2164 free(path); 2165 return NULL; 2166 } 2167 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2168 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2169 break; 2170 if (obj != NULL && name != NULL) { 2171 object_add_name(obj, name); 2172 free(path); 2173 close(fd); 2174 return obj; 2175 } 2176 if (flags & RTLD_LO_NOLOAD) { 2177 free(path); 2178 close(fd); 2179 return (NULL); 2180 } 2181 2182 /* First use of this object, so we must map it in */ 2183 obj = do_load_object(fd, name, path, &sb, flags); 2184 if (obj == NULL) 2185 free(path); 2186 close(fd); 2187 2188 return obj; 2189} 2190 2191static Obj_Entry * 2192do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2193 int flags) 2194{ 2195 Obj_Entry *obj; 2196 struct statfs fs; 2197 2198 /* 2199 * but first, make sure that environment variables haven't been 2200 * used to circumvent the noexec flag on a filesystem. 2201 */ 2202 if (dangerous_ld_env) { 2203 if (fstatfs(fd, &fs) != 0) { 2204 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2205 return NULL; 2206 } 2207 if (fs.f_flags & MNT_NOEXEC) { 2208 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2209 return NULL; 2210 } 2211 } 2212 dbg("loading \"%s\"", printable_path(path)); 2213 obj = map_object(fd, printable_path(path), sbp); 2214 if (obj == NULL) 2215 return NULL; 2216 2217 /* 2218 * If DT_SONAME is present in the object, digest_dynamic2 already 2219 * added it to the object names. 2220 */ 2221 if (name != NULL) 2222 object_add_name(obj, name); 2223 obj->path = path; 2224 digest_dynamic(obj, 0); 2225 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2226 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2227 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2228 RTLD_LO_DLOPEN) { 2229 dbg("refusing to load non-loadable \"%s\"", obj->path); 2230 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2231 munmap(obj->mapbase, obj->mapsize); 2232 obj_free(obj); 2233 return (NULL); 2234 } 2235 2236 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2237 *obj_tail = obj; 2238 obj_tail = &obj->next; 2239 obj_count++; 2240 obj_loads++; 2241 linkmap_add(obj); /* for GDB & dlinfo() */ 2242 max_stack_flags |= obj->stack_flags; 2243 2244 dbg(" %p .. %p: %s", obj->mapbase, 2245 obj->mapbase + obj->mapsize - 1, obj->path); 2246 if (obj->textrel) 2247 dbg(" WARNING: %s has impure text", obj->path); 2248 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2249 obj->path); 2250 2251 return obj; 2252} 2253 2254static Obj_Entry * 2255obj_from_addr(const void *addr) 2256{ 2257 Obj_Entry *obj; 2258 2259 for (obj = obj_list; obj != NULL; obj = obj->next) { 2260 if (addr < (void *) obj->mapbase) 2261 continue; 2262 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2263 return obj; 2264 } 2265 return NULL; 2266} 2267 2268static void 2269preinit_main(void) 2270{ 2271 Elf_Addr *preinit_addr; 2272 int index; 2273 2274 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2275 if (preinit_addr == NULL) 2276 return; 2277 2278 for (index = 0; index < obj_main->preinit_array_num; index++) { 2279 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2280 dbg("calling preinit function for %s at %p", obj_main->path, 2281 (void *)preinit_addr[index]); 2282 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2283 0, 0, obj_main->path); 2284 call_init_pointer(obj_main, preinit_addr[index]); 2285 } 2286 } 2287} 2288 2289/* 2290 * Call the finalization functions for each of the objects in "list" 2291 * belonging to the DAG of "root" and referenced once. If NULL "root" 2292 * is specified, every finalization function will be called regardless 2293 * of the reference count and the list elements won't be freed. All of 2294 * the objects are expected to have non-NULL fini functions. 2295 */ 2296static void 2297objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2298{ 2299 Objlist_Entry *elm; 2300 char *saved_msg; 2301 Elf_Addr *fini_addr; 2302 int index; 2303 2304 assert(root == NULL || root->refcount == 1); 2305 2306 /* 2307 * Preserve the current error message since a fini function might 2308 * call into the dynamic linker and overwrite it. 2309 */ 2310 saved_msg = errmsg_save(); 2311 do { 2312 STAILQ_FOREACH(elm, list, link) { 2313 if (root != NULL && (elm->obj->refcount != 1 || 2314 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2315 continue; 2316 /* Remove object from fini list to prevent recursive invocation. */ 2317 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2318 /* 2319 * XXX: If a dlopen() call references an object while the 2320 * fini function is in progress, we might end up trying to 2321 * unload the referenced object in dlclose() or the object 2322 * won't be unloaded although its fini function has been 2323 * called. 2324 */ 2325 lock_release(rtld_bind_lock, lockstate); 2326 2327 /* 2328 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2329 * When this happens, DT_FINI_ARRAY is processed first. 2330 */ 2331 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2332 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2333 for (index = elm->obj->fini_array_num - 1; index >= 0; 2334 index--) { 2335 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2336 dbg("calling fini function for %s at %p", 2337 elm->obj->path, (void *)fini_addr[index]); 2338 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2339 (void *)fini_addr[index], 0, 0, elm->obj->path); 2340 call_initfini_pointer(elm->obj, fini_addr[index]); 2341 } 2342 } 2343 } 2344 if (elm->obj->fini != (Elf_Addr)NULL) { 2345 dbg("calling fini function for %s at %p", elm->obj->path, 2346 (void *)elm->obj->fini); 2347 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2348 0, 0, elm->obj->path); 2349 call_initfini_pointer(elm->obj, elm->obj->fini); 2350 } 2351 wlock_acquire(rtld_bind_lock, lockstate); 2352 /* No need to free anything if process is going down. */ 2353 if (root != NULL) 2354 free(elm); 2355 /* 2356 * We must restart the list traversal after every fini call 2357 * because a dlclose() call from the fini function or from 2358 * another thread might have modified the reference counts. 2359 */ 2360 break; 2361 } 2362 } while (elm != NULL); 2363 errmsg_restore(saved_msg); 2364} 2365 2366/* 2367 * Call the initialization functions for each of the objects in 2368 * "list". All of the objects are expected to have non-NULL init 2369 * functions. 2370 */ 2371static void 2372objlist_call_init(Objlist *list, RtldLockState *lockstate) 2373{ 2374 Objlist_Entry *elm; 2375 Obj_Entry *obj; 2376 char *saved_msg; 2377 Elf_Addr *init_addr; 2378 int index; 2379 2380 /* 2381 * Clean init_scanned flag so that objects can be rechecked and 2382 * possibly initialized earlier if any of vectors called below 2383 * cause the change by using dlopen. 2384 */ 2385 for (obj = obj_list; obj != NULL; obj = obj->next) 2386 obj->init_scanned = false; 2387 2388 /* 2389 * Preserve the current error message since an init function might 2390 * call into the dynamic linker and overwrite it. 2391 */ 2392 saved_msg = errmsg_save(); 2393 STAILQ_FOREACH(elm, list, link) { 2394 if (elm->obj->init_done) /* Initialized early. */ 2395 continue; 2396 /* 2397 * Race: other thread might try to use this object before current 2398 * one completes the initilization. Not much can be done here 2399 * without better locking. 2400 */ 2401 elm->obj->init_done = true; 2402 lock_release(rtld_bind_lock, lockstate); 2403 2404 /* 2405 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2406 * When this happens, DT_INIT is processed first. 2407 */ 2408 if (elm->obj->init != (Elf_Addr)NULL) { 2409 dbg("calling init function for %s at %p", elm->obj->path, 2410 (void *)elm->obj->init); 2411 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2412 0, 0, elm->obj->path); 2413 call_initfini_pointer(elm->obj, elm->obj->init); 2414 } 2415 init_addr = (Elf_Addr *)elm->obj->init_array; 2416 if (init_addr != NULL) { 2417 for (index = 0; index < elm->obj->init_array_num; index++) { 2418 if (init_addr[index] != 0 && init_addr[index] != 1) { 2419 dbg("calling init function for %s at %p", elm->obj->path, 2420 (void *)init_addr[index]); 2421 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2422 (void *)init_addr[index], 0, 0, elm->obj->path); 2423 call_init_pointer(elm->obj, init_addr[index]); 2424 } 2425 } 2426 } 2427 wlock_acquire(rtld_bind_lock, lockstate); 2428 } 2429 errmsg_restore(saved_msg); 2430} 2431 2432static void 2433objlist_clear(Objlist *list) 2434{ 2435 Objlist_Entry *elm; 2436 2437 while (!STAILQ_EMPTY(list)) { 2438 elm = STAILQ_FIRST(list); 2439 STAILQ_REMOVE_HEAD(list, link); 2440 free(elm); 2441 } 2442} 2443 2444static Objlist_Entry * 2445objlist_find(Objlist *list, const Obj_Entry *obj) 2446{ 2447 Objlist_Entry *elm; 2448 2449 STAILQ_FOREACH(elm, list, link) 2450 if (elm->obj == obj) 2451 return elm; 2452 return NULL; 2453} 2454 2455static void 2456objlist_init(Objlist *list) 2457{ 2458 STAILQ_INIT(list); 2459} 2460 2461static void 2462objlist_push_head(Objlist *list, Obj_Entry *obj) 2463{ 2464 Objlist_Entry *elm; 2465 2466 elm = NEW(Objlist_Entry); 2467 elm->obj = obj; 2468 STAILQ_INSERT_HEAD(list, elm, link); 2469} 2470 2471static void 2472objlist_push_tail(Objlist *list, Obj_Entry *obj) 2473{ 2474 Objlist_Entry *elm; 2475 2476 elm = NEW(Objlist_Entry); 2477 elm->obj = obj; 2478 STAILQ_INSERT_TAIL(list, elm, link); 2479} 2480 2481static void 2482objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2483{ 2484 Objlist_Entry *elm, *listelm; 2485 2486 STAILQ_FOREACH(listelm, list, link) { 2487 if (listelm->obj == listobj) 2488 break; 2489 } 2490 elm = NEW(Objlist_Entry); 2491 elm->obj = obj; 2492 if (listelm != NULL) 2493 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2494 else 2495 STAILQ_INSERT_TAIL(list, elm, link); 2496} 2497 2498static void 2499objlist_remove(Objlist *list, Obj_Entry *obj) 2500{ 2501 Objlist_Entry *elm; 2502 2503 if ((elm = objlist_find(list, obj)) != NULL) { 2504 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2505 free(elm); 2506 } 2507} 2508 2509/* 2510 * Relocate dag rooted in the specified object. 2511 * Returns 0 on success, or -1 on failure. 2512 */ 2513 2514static int 2515relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2516 int flags, RtldLockState *lockstate) 2517{ 2518 Objlist_Entry *elm; 2519 int error; 2520 2521 error = 0; 2522 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2523 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2524 lockstate); 2525 if (error == -1) 2526 break; 2527 } 2528 return (error); 2529} 2530 2531/* 2532 * Relocate single object. 2533 * Returns 0 on success, or -1 on failure. 2534 */ 2535static int 2536relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2537 int flags, RtldLockState *lockstate) 2538{ 2539 2540 if (obj->relocated) 2541 return (0); 2542 obj->relocated = true; 2543 if (obj != rtldobj) 2544 dbg("relocating \"%s\"", obj->path); 2545 2546 if (obj->symtab == NULL || obj->strtab == NULL || 2547 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2548 _rtld_error("%s: Shared object has no run-time symbol table", 2549 obj->path); 2550 return (-1); 2551 } 2552 2553 if (obj->textrel) { 2554 /* There are relocations to the write-protected text segment. */ 2555 if (mprotect(obj->mapbase, obj->textsize, 2556 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2557 _rtld_error("%s: Cannot write-enable text segment: %s", 2558 obj->path, rtld_strerror(errno)); 2559 return (-1); 2560 } 2561 } 2562 2563 /* Process the non-PLT non-IFUNC relocations. */ 2564 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2565 return (-1); 2566 2567 if (obj->textrel) { /* Re-protected the text segment. */ 2568 if (mprotect(obj->mapbase, obj->textsize, 2569 PROT_READ|PROT_EXEC) == -1) { 2570 _rtld_error("%s: Cannot write-protect text segment: %s", 2571 obj->path, rtld_strerror(errno)); 2572 return (-1); 2573 } 2574 } 2575 2576 /* Set the special PLT or GOT entries. */ 2577 init_pltgot(obj); 2578 2579 /* Process the PLT relocations. */ 2580 if (reloc_plt(obj) == -1) 2581 return (-1); 2582 /* Relocate the jump slots if we are doing immediate binding. */ 2583 if (obj->bind_now || bind_now) 2584 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2585 return (-1); 2586 2587 /* 2588 * Process the non-PLT IFUNC relocations. The relocations are 2589 * processed in two phases, because IFUNC resolvers may 2590 * reference other symbols, which must be readily processed 2591 * before resolvers are called. 2592 */ 2593 if (obj->non_plt_gnu_ifunc && 2594 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2595 return (-1); 2596 2597 if (obj->relro_size > 0) { 2598 if (mprotect(obj->relro_page, obj->relro_size, 2599 PROT_READ) == -1) { 2600 _rtld_error("%s: Cannot enforce relro protection: %s", 2601 obj->path, rtld_strerror(errno)); 2602 return (-1); 2603 } 2604 } 2605 2606 /* 2607 * Set up the magic number and version in the Obj_Entry. These 2608 * were checked in the crt1.o from the original ElfKit, so we 2609 * set them for backward compatibility. 2610 */ 2611 obj->magic = RTLD_MAGIC; 2612 obj->version = RTLD_VERSION; 2613 2614 return (0); 2615} 2616 2617/* 2618 * Relocate newly-loaded shared objects. The argument is a pointer to 2619 * the Obj_Entry for the first such object. All objects from the first 2620 * to the end of the list of objects are relocated. Returns 0 on success, 2621 * or -1 on failure. 2622 */ 2623static int 2624relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2625 int flags, RtldLockState *lockstate) 2626{ 2627 Obj_Entry *obj; 2628 int error; 2629 2630 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2631 error = relocate_object(obj, bind_now, rtldobj, flags, 2632 lockstate); 2633 if (error == -1) 2634 break; 2635 } 2636 return (error); 2637} 2638 2639/* 2640 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2641 * referencing STT_GNU_IFUNC symbols is postponed till the other 2642 * relocations are done. The indirect functions specified as 2643 * ifunc are allowed to call other symbols, so we need to have 2644 * objects relocated before asking for resolution from indirects. 2645 * 2646 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2647 * instead of the usual lazy handling of PLT slots. It is 2648 * consistent with how GNU does it. 2649 */ 2650static int 2651resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2652 RtldLockState *lockstate) 2653{ 2654 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2655 return (-1); 2656 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2657 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2658 return (-1); 2659 return (0); 2660} 2661 2662static int 2663resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2664 RtldLockState *lockstate) 2665{ 2666 Obj_Entry *obj; 2667 2668 for (obj = first; obj != NULL; obj = obj->next) { 2669 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2670 return (-1); 2671 } 2672 return (0); 2673} 2674 2675static int 2676initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2677 RtldLockState *lockstate) 2678{ 2679 Objlist_Entry *elm; 2680 2681 STAILQ_FOREACH(elm, list, link) { 2682 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2683 lockstate) == -1) 2684 return (-1); 2685 } 2686 return (0); 2687} 2688 2689/* 2690 * Cleanup procedure. It will be called (by the atexit mechanism) just 2691 * before the process exits. 2692 */ 2693static void 2694rtld_exit(void) 2695{ 2696 RtldLockState lockstate; 2697 2698 wlock_acquire(rtld_bind_lock, &lockstate); 2699 dbg("rtld_exit()"); 2700 objlist_call_fini(&list_fini, NULL, &lockstate); 2701 /* No need to remove the items from the list, since we are exiting. */ 2702 if (!libmap_disable) 2703 lm_fini(); 2704 lock_release(rtld_bind_lock, &lockstate); 2705} 2706 2707/* 2708 * Iterate over a search path, translate each element, and invoke the 2709 * callback on the result. 2710 */ 2711static void * 2712path_enumerate(const char *path, path_enum_proc callback, void *arg) 2713{ 2714 const char *trans; 2715 if (path == NULL) 2716 return (NULL); 2717 2718 path += strspn(path, ":;"); 2719 while (*path != '\0') { 2720 size_t len; 2721 char *res; 2722 2723 len = strcspn(path, ":;"); 2724 trans = lm_findn(NULL, path, len); 2725 if (trans) 2726 res = callback(trans, strlen(trans), arg); 2727 else 2728 res = callback(path, len, arg); 2729 2730 if (res != NULL) 2731 return (res); 2732 2733 path += len; 2734 path += strspn(path, ":;"); 2735 } 2736 2737 return (NULL); 2738} 2739 2740struct try_library_args { 2741 const char *name; 2742 size_t namelen; 2743 char *buffer; 2744 size_t buflen; 2745}; 2746 2747static void * 2748try_library_path(const char *dir, size_t dirlen, void *param) 2749{ 2750 struct try_library_args *arg; 2751 2752 arg = param; 2753 if (*dir == '/' || trust) { 2754 char *pathname; 2755 2756 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2757 return (NULL); 2758 2759 pathname = arg->buffer; 2760 strncpy(pathname, dir, dirlen); 2761 pathname[dirlen] = '/'; 2762 strcpy(pathname + dirlen + 1, arg->name); 2763 2764 dbg(" Trying \"%s\"", pathname); 2765 if (access(pathname, F_OK) == 0) { /* We found it */ 2766 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2767 strcpy(pathname, arg->buffer); 2768 return (pathname); 2769 } 2770 } 2771 return (NULL); 2772} 2773 2774static char * 2775search_library_path(const char *name, const char *path) 2776{ 2777 char *p; 2778 struct try_library_args arg; 2779 2780 if (path == NULL) 2781 return NULL; 2782 2783 arg.name = name; 2784 arg.namelen = strlen(name); 2785 arg.buffer = xmalloc(PATH_MAX); 2786 arg.buflen = PATH_MAX; 2787 2788 p = path_enumerate(path, try_library_path, &arg); 2789 2790 free(arg.buffer); 2791 2792 return (p); 2793} 2794 2795int 2796dlclose(void *handle) 2797{ 2798 Obj_Entry *root; 2799 RtldLockState lockstate; 2800 2801 wlock_acquire(rtld_bind_lock, &lockstate); 2802 root = dlcheck(handle); 2803 if (root == NULL) { 2804 lock_release(rtld_bind_lock, &lockstate); 2805 return -1; 2806 } 2807 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2808 root->path); 2809 2810 /* Unreference the object and its dependencies. */ 2811 root->dl_refcount--; 2812 2813 if (root->refcount == 1) { 2814 /* 2815 * The object will be no longer referenced, so we must unload it. 2816 * First, call the fini functions. 2817 */ 2818 objlist_call_fini(&list_fini, root, &lockstate); 2819 2820 unref_dag(root); 2821 2822 /* Finish cleaning up the newly-unreferenced objects. */ 2823 GDB_STATE(RT_DELETE,&root->linkmap); 2824 unload_object(root); 2825 GDB_STATE(RT_CONSISTENT,NULL); 2826 } else 2827 unref_dag(root); 2828 2829 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2830 lock_release(rtld_bind_lock, &lockstate); 2831 return 0; 2832} 2833 2834char * 2835dlerror(void) 2836{ 2837 char *msg = error_message; 2838 error_message = NULL; 2839 return msg; 2840} 2841 2842/* 2843 * This function is deprecated and has no effect. 2844 */ 2845void 2846dllockinit(void *context, 2847 void *(*lock_create)(void *context), 2848 void (*rlock_acquire)(void *lock), 2849 void (*wlock_acquire)(void *lock), 2850 void (*lock_release)(void *lock), 2851 void (*lock_destroy)(void *lock), 2852 void (*context_destroy)(void *context)) 2853{ 2854 static void *cur_context; 2855 static void (*cur_context_destroy)(void *); 2856 2857 /* Just destroy the context from the previous call, if necessary. */ 2858 if (cur_context_destroy != NULL) 2859 cur_context_destroy(cur_context); 2860 cur_context = context; 2861 cur_context_destroy = context_destroy; 2862} 2863 2864void * 2865dlopen(const char *name, int mode) 2866{ 2867 2868 return (rtld_dlopen(name, -1, mode)); 2869} 2870 2871void * 2872fdlopen(int fd, int mode) 2873{ 2874 2875 return (rtld_dlopen(NULL, fd, mode)); 2876} 2877 2878static void * 2879rtld_dlopen(const char *name, int fd, int mode) 2880{ 2881 RtldLockState lockstate; 2882 int lo_flags; 2883 2884 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2885 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2886 if (ld_tracing != NULL) { 2887 rlock_acquire(rtld_bind_lock, &lockstate); 2888 if (sigsetjmp(lockstate.env, 0) != 0) 2889 lock_upgrade(rtld_bind_lock, &lockstate); 2890 environ = (char **)*get_program_var_addr("environ", &lockstate); 2891 lock_release(rtld_bind_lock, &lockstate); 2892 } 2893 lo_flags = RTLD_LO_DLOPEN; 2894 if (mode & RTLD_NODELETE) 2895 lo_flags |= RTLD_LO_NODELETE; 2896 if (mode & RTLD_NOLOAD) 2897 lo_flags |= RTLD_LO_NOLOAD; 2898 if (ld_tracing != NULL) 2899 lo_flags |= RTLD_LO_TRACE; 2900 2901 return (dlopen_object(name, fd, obj_main, lo_flags, 2902 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2903} 2904 2905static void 2906dlopen_cleanup(Obj_Entry *obj) 2907{ 2908 2909 obj->dl_refcount--; 2910 unref_dag(obj); 2911 if (obj->refcount == 0) 2912 unload_object(obj); 2913} 2914 2915static Obj_Entry * 2916dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2917 int mode, RtldLockState *lockstate) 2918{ 2919 Obj_Entry **old_obj_tail; 2920 Obj_Entry *obj; 2921 Objlist initlist; 2922 RtldLockState mlockstate; 2923 int result; 2924 2925 objlist_init(&initlist); 2926 2927 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2928 wlock_acquire(rtld_bind_lock, &mlockstate); 2929 lockstate = &mlockstate; 2930 } 2931 GDB_STATE(RT_ADD,NULL); 2932 2933 old_obj_tail = obj_tail; 2934 obj = NULL; 2935 if (name == NULL && fd == -1) { 2936 obj = obj_main; 2937 obj->refcount++; 2938 } else { 2939 obj = load_object(name, fd, refobj, lo_flags); 2940 } 2941 2942 if (obj) { 2943 obj->dl_refcount++; 2944 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2945 objlist_push_tail(&list_global, obj); 2946 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2947 assert(*old_obj_tail == obj); 2948 result = load_needed_objects(obj, 2949 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2950 init_dag(obj); 2951 ref_dag(obj); 2952 if (result != -1) 2953 result = rtld_verify_versions(&obj->dagmembers); 2954 if (result != -1 && ld_tracing) 2955 goto trace; 2956 if (result == -1 || relocate_object_dag(obj, 2957 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2958 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2959 lockstate) == -1) { 2960 dlopen_cleanup(obj); 2961 obj = NULL; 2962 } else if (lo_flags & RTLD_LO_EARLY) { 2963 /* 2964 * Do not call the init functions for early loaded 2965 * filtees. The image is still not initialized enough 2966 * for them to work. 2967 * 2968 * Our object is found by the global object list and 2969 * will be ordered among all init calls done right 2970 * before transferring control to main. 2971 */ 2972 } else { 2973 /* Make list of init functions to call. */ 2974 initlist_add_objects(obj, &obj->next, &initlist); 2975 } 2976 /* 2977 * Process all no_delete or global objects here, given 2978 * them own DAGs to prevent their dependencies from being 2979 * unloaded. This has to be done after we have loaded all 2980 * of the dependencies, so that we do not miss any. 2981 */ 2982 if (obj != NULL) 2983 process_z(obj); 2984 } else { 2985 /* 2986 * Bump the reference counts for objects on this DAG. If 2987 * this is the first dlopen() call for the object that was 2988 * already loaded as a dependency, initialize the dag 2989 * starting at it. 2990 */ 2991 init_dag(obj); 2992 ref_dag(obj); 2993 2994 if ((lo_flags & RTLD_LO_TRACE) != 0) 2995 goto trace; 2996 } 2997 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2998 obj->z_nodelete) && !obj->ref_nodel) { 2999 dbg("obj %s nodelete", obj->path); 3000 ref_dag(obj); 3001 obj->z_nodelete = obj->ref_nodel = true; 3002 } 3003 } 3004 3005 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3006 name); 3007 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3008 3009 if (!(lo_flags & RTLD_LO_EARLY)) { 3010 map_stacks_exec(lockstate); 3011 } 3012 3013 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3014 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3015 lockstate) == -1) { 3016 objlist_clear(&initlist); 3017 dlopen_cleanup(obj); 3018 if (lockstate == &mlockstate) 3019 lock_release(rtld_bind_lock, lockstate); 3020 return (NULL); 3021 } 3022 3023 if (!(lo_flags & RTLD_LO_EARLY)) { 3024 /* Call the init functions. */ 3025 objlist_call_init(&initlist, lockstate); 3026 } 3027 objlist_clear(&initlist); 3028 if (lockstate == &mlockstate) 3029 lock_release(rtld_bind_lock, lockstate); 3030 return obj; 3031trace: 3032 trace_loaded_objects(obj); 3033 if (lockstate == &mlockstate) 3034 lock_release(rtld_bind_lock, lockstate); 3035 exit(0); 3036} 3037 3038static void * 3039do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3040 int flags) 3041{ 3042 DoneList donelist; 3043 const Obj_Entry *obj, *defobj; 3044 const Elf_Sym *def; 3045 SymLook req; 3046 RtldLockState lockstate; 3047#ifndef __ia64__ 3048 tls_index ti; 3049#endif 3050 int res; 3051 3052 def = NULL; 3053 defobj = NULL; 3054 symlook_init(&req, name); 3055 req.ventry = ve; 3056 req.flags = flags | SYMLOOK_IN_PLT; 3057 req.lockstate = &lockstate; 3058 3059 rlock_acquire(rtld_bind_lock, &lockstate); 3060 if (sigsetjmp(lockstate.env, 0) != 0) 3061 lock_upgrade(rtld_bind_lock, &lockstate); 3062 if (handle == NULL || handle == RTLD_NEXT || 3063 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3064 3065 if ((obj = obj_from_addr(retaddr)) == NULL) { 3066 _rtld_error("Cannot determine caller's shared object"); 3067 lock_release(rtld_bind_lock, &lockstate); 3068 return NULL; 3069 } 3070 if (handle == NULL) { /* Just the caller's shared object. */ 3071 res = symlook_obj(&req, obj); 3072 if (res == 0) { 3073 def = req.sym_out; 3074 defobj = req.defobj_out; 3075 } 3076 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3077 handle == RTLD_SELF) { /* ... caller included */ 3078 if (handle == RTLD_NEXT) 3079 obj = obj->next; 3080 for (; obj != NULL; obj = obj->next) { 3081 res = symlook_obj(&req, obj); 3082 if (res == 0) { 3083 if (def == NULL || 3084 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3085 def = req.sym_out; 3086 defobj = req.defobj_out; 3087 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3088 break; 3089 } 3090 } 3091 } 3092 /* 3093 * Search the dynamic linker itself, and possibly resolve the 3094 * symbol from there. This is how the application links to 3095 * dynamic linker services such as dlopen. 3096 */ 3097 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3098 res = symlook_obj(&req, &obj_rtld); 3099 if (res == 0) { 3100 def = req.sym_out; 3101 defobj = req.defobj_out; 3102 } 3103 } 3104 } else { 3105 assert(handle == RTLD_DEFAULT); 3106 res = symlook_default(&req, obj); 3107 if (res == 0) { 3108 defobj = req.defobj_out; 3109 def = req.sym_out; 3110 } 3111 } 3112 } else { 3113 if ((obj = dlcheck(handle)) == NULL) { 3114 lock_release(rtld_bind_lock, &lockstate); 3115 return NULL; 3116 } 3117 3118 donelist_init(&donelist); 3119 if (obj->mainprog) { 3120 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3121 res = symlook_global(&req, &donelist); 3122 if (res == 0) { 3123 def = req.sym_out; 3124 defobj = req.defobj_out; 3125 } 3126 /* 3127 * Search the dynamic linker itself, and possibly resolve the 3128 * symbol from there. This is how the application links to 3129 * dynamic linker services such as dlopen. 3130 */ 3131 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3132 res = symlook_obj(&req, &obj_rtld); 3133 if (res == 0) { 3134 def = req.sym_out; 3135 defobj = req.defobj_out; 3136 } 3137 } 3138 } 3139 else { 3140 /* Search the whole DAG rooted at the given object. */ 3141 res = symlook_list(&req, &obj->dagmembers, &donelist); 3142 if (res == 0) { 3143 def = req.sym_out; 3144 defobj = req.defobj_out; 3145 } 3146 } 3147 } 3148 3149 if (def != NULL) { 3150 lock_release(rtld_bind_lock, &lockstate); 3151 3152 /* 3153 * The value required by the caller is derived from the value 3154 * of the symbol. For the ia64 architecture, we need to 3155 * construct a function descriptor which the caller can use to 3156 * call the function with the right 'gp' value. For other 3157 * architectures and for non-functions, the value is simply 3158 * the relocated value of the symbol. 3159 */ 3160 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3161 return (make_function_pointer(def, defobj)); 3162 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3163 return (rtld_resolve_ifunc(defobj, def)); 3164 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3165#ifdef __ia64__ 3166 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3167#else 3168 ti.ti_module = defobj->tlsindex; 3169 ti.ti_offset = def->st_value; 3170 return (__tls_get_addr(&ti)); 3171#endif 3172 } else 3173 return (defobj->relocbase + def->st_value); 3174 } 3175 3176 _rtld_error("Undefined symbol \"%s\"", name); 3177 lock_release(rtld_bind_lock, &lockstate); 3178 return NULL; 3179} 3180 3181void * 3182dlsym(void *handle, const char *name) 3183{ 3184 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3185 SYMLOOK_DLSYM); 3186} 3187 3188dlfunc_t 3189dlfunc(void *handle, const char *name) 3190{ 3191 union { 3192 void *d; 3193 dlfunc_t f; 3194 } rv; 3195 3196 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3197 SYMLOOK_DLSYM); 3198 return (rv.f); 3199} 3200 3201void * 3202dlvsym(void *handle, const char *name, const char *version) 3203{ 3204 Ver_Entry ventry; 3205 3206 ventry.name = version; 3207 ventry.file = NULL; 3208 ventry.hash = elf_hash(version); 3209 ventry.flags= 0; 3210 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3211 SYMLOOK_DLSYM); 3212} 3213 3214int 3215_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3216{ 3217 const Obj_Entry *obj; 3218 RtldLockState lockstate; 3219 3220 rlock_acquire(rtld_bind_lock, &lockstate); 3221 obj = obj_from_addr(addr); 3222 if (obj == NULL) { 3223 _rtld_error("No shared object contains address"); 3224 lock_release(rtld_bind_lock, &lockstate); 3225 return (0); 3226 } 3227 rtld_fill_dl_phdr_info(obj, phdr_info); 3228 lock_release(rtld_bind_lock, &lockstate); 3229 return (1); 3230} 3231 3232int 3233dladdr(const void *addr, Dl_info *info) 3234{ 3235 const Obj_Entry *obj; 3236 const Elf_Sym *def; 3237 void *symbol_addr; 3238 unsigned long symoffset; 3239 RtldLockState lockstate; 3240 3241 rlock_acquire(rtld_bind_lock, &lockstate); 3242 obj = obj_from_addr(addr); 3243 if (obj == NULL) { 3244 _rtld_error("No shared object contains address"); 3245 lock_release(rtld_bind_lock, &lockstate); 3246 return 0; 3247 } 3248 info->dli_fname = obj->path; 3249 info->dli_fbase = obj->mapbase; 3250 info->dli_saddr = (void *)0; 3251 info->dli_sname = NULL; 3252 3253 /* 3254 * Walk the symbol list looking for the symbol whose address is 3255 * closest to the address sent in. 3256 */ 3257 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3258 def = obj->symtab + symoffset; 3259 3260 /* 3261 * For skip the symbol if st_shndx is either SHN_UNDEF or 3262 * SHN_COMMON. 3263 */ 3264 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3265 continue; 3266 3267 /* 3268 * If the symbol is greater than the specified address, or if it 3269 * is further away from addr than the current nearest symbol, 3270 * then reject it. 3271 */ 3272 symbol_addr = obj->relocbase + def->st_value; 3273 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3274 continue; 3275 3276 /* Update our idea of the nearest symbol. */ 3277 info->dli_sname = obj->strtab + def->st_name; 3278 info->dli_saddr = symbol_addr; 3279 3280 /* Exact match? */ 3281 if (info->dli_saddr == addr) 3282 break; 3283 } 3284 lock_release(rtld_bind_lock, &lockstate); 3285 return 1; 3286} 3287 3288int 3289dlinfo(void *handle, int request, void *p) 3290{ 3291 const Obj_Entry *obj; 3292 RtldLockState lockstate; 3293 int error; 3294 3295 rlock_acquire(rtld_bind_lock, &lockstate); 3296 3297 if (handle == NULL || handle == RTLD_SELF) { 3298 void *retaddr; 3299 3300 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3301 if ((obj = obj_from_addr(retaddr)) == NULL) 3302 _rtld_error("Cannot determine caller's shared object"); 3303 } else 3304 obj = dlcheck(handle); 3305 3306 if (obj == NULL) { 3307 lock_release(rtld_bind_lock, &lockstate); 3308 return (-1); 3309 } 3310 3311 error = 0; 3312 switch (request) { 3313 case RTLD_DI_LINKMAP: 3314 *((struct link_map const **)p) = &obj->linkmap; 3315 break; 3316 case RTLD_DI_ORIGIN: 3317 error = rtld_dirname(obj->path, p); 3318 break; 3319 3320 case RTLD_DI_SERINFOSIZE: 3321 case RTLD_DI_SERINFO: 3322 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3323 break; 3324 3325 default: 3326 _rtld_error("Invalid request %d passed to dlinfo()", request); 3327 error = -1; 3328 } 3329 3330 lock_release(rtld_bind_lock, &lockstate); 3331 3332 return (error); 3333} 3334 3335static void 3336rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3337{ 3338 3339 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3340 phdr_info->dlpi_name = obj->path; 3341 phdr_info->dlpi_phdr = obj->phdr; 3342 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3343 phdr_info->dlpi_tls_modid = obj->tlsindex; 3344 phdr_info->dlpi_tls_data = obj->tlsinit; 3345 phdr_info->dlpi_adds = obj_loads; 3346 phdr_info->dlpi_subs = obj_loads - obj_count; 3347} 3348 3349int 3350dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3351{ 3352 struct dl_phdr_info phdr_info; 3353 const Obj_Entry *obj; 3354 RtldLockState bind_lockstate, phdr_lockstate; 3355 int error; 3356 3357 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3358 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3359 3360 error = 0; 3361 3362 for (obj = obj_list; obj != NULL; obj = obj->next) { 3363 rtld_fill_dl_phdr_info(obj, &phdr_info); 3364 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3365 break; 3366 3367 } 3368 lock_release(rtld_bind_lock, &bind_lockstate); 3369 lock_release(rtld_phdr_lock, &phdr_lockstate); 3370 3371 return (error); 3372} 3373 3374static void * 3375fill_search_info(const char *dir, size_t dirlen, void *param) 3376{ 3377 struct fill_search_info_args *arg; 3378 3379 arg = param; 3380 3381 if (arg->request == RTLD_DI_SERINFOSIZE) { 3382 arg->serinfo->dls_cnt ++; 3383 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3384 } else { 3385 struct dl_serpath *s_entry; 3386 3387 s_entry = arg->serpath; 3388 s_entry->dls_name = arg->strspace; 3389 s_entry->dls_flags = arg->flags; 3390 3391 strncpy(arg->strspace, dir, dirlen); 3392 arg->strspace[dirlen] = '\0'; 3393 3394 arg->strspace += dirlen + 1; 3395 arg->serpath++; 3396 } 3397 3398 return (NULL); 3399} 3400 3401static int 3402do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3403{ 3404 struct dl_serinfo _info; 3405 struct fill_search_info_args args; 3406 3407 args.request = RTLD_DI_SERINFOSIZE; 3408 args.serinfo = &_info; 3409 3410 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3411 _info.dls_cnt = 0; 3412 3413 path_enumerate(obj->rpath, fill_search_info, &args); 3414 path_enumerate(ld_library_path, fill_search_info, &args); 3415 path_enumerate(obj->runpath, fill_search_info, &args); 3416 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3417 if (!obj->z_nodeflib) 3418 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3419 3420 3421 if (request == RTLD_DI_SERINFOSIZE) { 3422 info->dls_size = _info.dls_size; 3423 info->dls_cnt = _info.dls_cnt; 3424 return (0); 3425 } 3426 3427 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3428 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3429 return (-1); 3430 } 3431 3432 args.request = RTLD_DI_SERINFO; 3433 args.serinfo = info; 3434 args.serpath = &info->dls_serpath[0]; 3435 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3436 3437 args.flags = LA_SER_RUNPATH; 3438 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3439 return (-1); 3440 3441 args.flags = LA_SER_LIBPATH; 3442 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3443 return (-1); 3444 3445 args.flags = LA_SER_RUNPATH; 3446 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3447 return (-1); 3448 3449 args.flags = LA_SER_CONFIG; 3450 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3451 != NULL) 3452 return (-1); 3453 3454 args.flags = LA_SER_DEFAULT; 3455 if (!obj->z_nodeflib && 3456 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3457 return (-1); 3458 return (0); 3459} 3460 3461static int 3462rtld_dirname(const char *path, char *bname) 3463{ 3464 const char *endp; 3465 3466 /* Empty or NULL string gets treated as "." */ 3467 if (path == NULL || *path == '\0') { 3468 bname[0] = '.'; 3469 bname[1] = '\0'; 3470 return (0); 3471 } 3472 3473 /* Strip trailing slashes */ 3474 endp = path + strlen(path) - 1; 3475 while (endp > path && *endp == '/') 3476 endp--; 3477 3478 /* Find the start of the dir */ 3479 while (endp > path && *endp != '/') 3480 endp--; 3481 3482 /* Either the dir is "/" or there are no slashes */ 3483 if (endp == path) { 3484 bname[0] = *endp == '/' ? '/' : '.'; 3485 bname[1] = '\0'; 3486 return (0); 3487 } else { 3488 do { 3489 endp--; 3490 } while (endp > path && *endp == '/'); 3491 } 3492 3493 if (endp - path + 2 > PATH_MAX) 3494 { 3495 _rtld_error("Filename is too long: %s", path); 3496 return(-1); 3497 } 3498 3499 strncpy(bname, path, endp - path + 1); 3500 bname[endp - path + 1] = '\0'; 3501 return (0); 3502} 3503 3504static int 3505rtld_dirname_abs(const char *path, char *base) 3506{ 3507 char *last; 3508 3509 if (realpath(path, base) == NULL) 3510 return (-1); 3511 dbg("%s -> %s", path, base); 3512 last = strrchr(base, '/'); 3513 if (last == NULL) 3514 return (-1); 3515 if (last != base) 3516 *last = '\0'; 3517 return (0); 3518} 3519 3520static void 3521linkmap_add(Obj_Entry *obj) 3522{ 3523 struct link_map *l = &obj->linkmap; 3524 struct link_map *prev; 3525 3526 obj->linkmap.l_name = obj->path; 3527 obj->linkmap.l_addr = obj->mapbase; 3528 obj->linkmap.l_ld = obj->dynamic; 3529#ifdef __mips__ 3530 /* GDB needs load offset on MIPS to use the symbols */ 3531 obj->linkmap.l_offs = obj->relocbase; 3532#endif 3533 3534 if (r_debug.r_map == NULL) { 3535 r_debug.r_map = l; 3536 return; 3537 } 3538 3539 /* 3540 * Scan to the end of the list, but not past the entry for the 3541 * dynamic linker, which we want to keep at the very end. 3542 */ 3543 for (prev = r_debug.r_map; 3544 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3545 prev = prev->l_next) 3546 ; 3547 3548 /* Link in the new entry. */ 3549 l->l_prev = prev; 3550 l->l_next = prev->l_next; 3551 if (l->l_next != NULL) 3552 l->l_next->l_prev = l; 3553 prev->l_next = l; 3554} 3555 3556static void 3557linkmap_delete(Obj_Entry *obj) 3558{ 3559 struct link_map *l = &obj->linkmap; 3560 3561 if (l->l_prev == NULL) { 3562 if ((r_debug.r_map = l->l_next) != NULL) 3563 l->l_next->l_prev = NULL; 3564 return; 3565 } 3566 3567 if ((l->l_prev->l_next = l->l_next) != NULL) 3568 l->l_next->l_prev = l->l_prev; 3569} 3570 3571/* 3572 * Function for the debugger to set a breakpoint on to gain control. 3573 * 3574 * The two parameters allow the debugger to easily find and determine 3575 * what the runtime loader is doing and to whom it is doing it. 3576 * 3577 * When the loadhook trap is hit (r_debug_state, set at program 3578 * initialization), the arguments can be found on the stack: 3579 * 3580 * +8 struct link_map *m 3581 * +4 struct r_debug *rd 3582 * +0 RetAddr 3583 */ 3584void 3585r_debug_state(struct r_debug* rd, struct link_map *m) 3586{ 3587 /* 3588 * The following is a hack to force the compiler to emit calls to 3589 * this function, even when optimizing. If the function is empty, 3590 * the compiler is not obliged to emit any code for calls to it, 3591 * even when marked __noinline. However, gdb depends on those 3592 * calls being made. 3593 */ 3594 __compiler_membar(); 3595} 3596 3597/* 3598 * A function called after init routines have completed. This can be used to 3599 * break before a program's entry routine is called, and can be used when 3600 * main is not available in the symbol table. 3601 */ 3602void 3603_r_debug_postinit(struct link_map *m) 3604{ 3605 3606 /* See r_debug_state(). */ 3607 __compiler_membar(); 3608} 3609 3610/* 3611 * Get address of the pointer variable in the main program. 3612 * Prefer non-weak symbol over the weak one. 3613 */ 3614static const void ** 3615get_program_var_addr(const char *name, RtldLockState *lockstate) 3616{ 3617 SymLook req; 3618 DoneList donelist; 3619 3620 symlook_init(&req, name); 3621 req.lockstate = lockstate; 3622 donelist_init(&donelist); 3623 if (symlook_global(&req, &donelist) != 0) 3624 return (NULL); 3625 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3626 return ((const void **)make_function_pointer(req.sym_out, 3627 req.defobj_out)); 3628 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3629 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3630 else 3631 return ((const void **)(req.defobj_out->relocbase + 3632 req.sym_out->st_value)); 3633} 3634 3635/* 3636 * Set a pointer variable in the main program to the given value. This 3637 * is used to set key variables such as "environ" before any of the 3638 * init functions are called. 3639 */ 3640static void 3641set_program_var(const char *name, const void *value) 3642{ 3643 const void **addr; 3644 3645 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3646 dbg("\"%s\": *%p <-- %p", name, addr, value); 3647 *addr = value; 3648 } 3649} 3650 3651/* 3652 * Search the global objects, including dependencies and main object, 3653 * for the given symbol. 3654 */ 3655static int 3656symlook_global(SymLook *req, DoneList *donelist) 3657{ 3658 SymLook req1; 3659 const Objlist_Entry *elm; 3660 int res; 3661 3662 symlook_init_from_req(&req1, req); 3663 3664 /* Search all objects loaded at program start up. */ 3665 if (req->defobj_out == NULL || 3666 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3667 res = symlook_list(&req1, &list_main, donelist); 3668 if (res == 0 && (req->defobj_out == NULL || 3669 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3670 req->sym_out = req1.sym_out; 3671 req->defobj_out = req1.defobj_out; 3672 assert(req->defobj_out != NULL); 3673 } 3674 } 3675 3676 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3677 STAILQ_FOREACH(elm, &list_global, link) { 3678 if (req->defobj_out != NULL && 3679 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3680 break; 3681 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3682 if (res == 0 && (req->defobj_out == NULL || 3683 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3684 req->sym_out = req1.sym_out; 3685 req->defobj_out = req1.defobj_out; 3686 assert(req->defobj_out != NULL); 3687 } 3688 } 3689 3690 return (req->sym_out != NULL ? 0 : ESRCH); 3691} 3692 3693/* 3694 * Given a symbol name in a referencing object, find the corresponding 3695 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3696 * no definition was found. Returns a pointer to the Obj_Entry of the 3697 * defining object via the reference parameter DEFOBJ_OUT. 3698 */ 3699static int 3700symlook_default(SymLook *req, const Obj_Entry *refobj) 3701{ 3702 DoneList donelist; 3703 const Objlist_Entry *elm; 3704 SymLook req1; 3705 int res; 3706 3707 donelist_init(&donelist); 3708 symlook_init_from_req(&req1, req); 3709 3710 /* Look first in the referencing object if linked symbolically. */ 3711 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3712 res = symlook_obj(&req1, refobj); 3713 if (res == 0) { 3714 req->sym_out = req1.sym_out; 3715 req->defobj_out = req1.defobj_out; 3716 assert(req->defobj_out != NULL); 3717 } 3718 } 3719 3720 symlook_global(req, &donelist); 3721 3722 /* Search all dlopened DAGs containing the referencing object. */ 3723 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3724 if (req->sym_out != NULL && 3725 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3726 break; 3727 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3728 if (res == 0 && (req->sym_out == NULL || 3729 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3730 req->sym_out = req1.sym_out; 3731 req->defobj_out = req1.defobj_out; 3732 assert(req->defobj_out != NULL); 3733 } 3734 } 3735 3736 /* 3737 * Search the dynamic linker itself, and possibly resolve the 3738 * symbol from there. This is how the application links to 3739 * dynamic linker services such as dlopen. 3740 */ 3741 if (req->sym_out == NULL || 3742 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3743 res = symlook_obj(&req1, &obj_rtld); 3744 if (res == 0) { 3745 req->sym_out = req1.sym_out; 3746 req->defobj_out = req1.defobj_out; 3747 assert(req->defobj_out != NULL); 3748 } 3749 } 3750 3751 return (req->sym_out != NULL ? 0 : ESRCH); 3752} 3753 3754static int 3755symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3756{ 3757 const Elf_Sym *def; 3758 const Obj_Entry *defobj; 3759 const Objlist_Entry *elm; 3760 SymLook req1; 3761 int res; 3762 3763 def = NULL; 3764 defobj = NULL; 3765 STAILQ_FOREACH(elm, objlist, link) { 3766 if (donelist_check(dlp, elm->obj)) 3767 continue; 3768 symlook_init_from_req(&req1, req); 3769 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3770 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3771 def = req1.sym_out; 3772 defobj = req1.defobj_out; 3773 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3774 break; 3775 } 3776 } 3777 } 3778 if (def != NULL) { 3779 req->sym_out = def; 3780 req->defobj_out = defobj; 3781 return (0); 3782 } 3783 return (ESRCH); 3784} 3785 3786/* 3787 * Search the chain of DAGS cointed to by the given Needed_Entry 3788 * for a symbol of the given name. Each DAG is scanned completely 3789 * before advancing to the next one. Returns a pointer to the symbol, 3790 * or NULL if no definition was found. 3791 */ 3792static int 3793symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3794{ 3795 const Elf_Sym *def; 3796 const Needed_Entry *n; 3797 const Obj_Entry *defobj; 3798 SymLook req1; 3799 int res; 3800 3801 def = NULL; 3802 defobj = NULL; 3803 symlook_init_from_req(&req1, req); 3804 for (n = needed; n != NULL; n = n->next) { 3805 if (n->obj == NULL || 3806 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3807 continue; 3808 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3809 def = req1.sym_out; 3810 defobj = req1.defobj_out; 3811 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3812 break; 3813 } 3814 } 3815 if (def != NULL) { 3816 req->sym_out = def; 3817 req->defobj_out = defobj; 3818 return (0); 3819 } 3820 return (ESRCH); 3821} 3822 3823/* 3824 * Search the symbol table of a single shared object for a symbol of 3825 * the given name and version, if requested. Returns a pointer to the 3826 * symbol, or NULL if no definition was found. If the object is 3827 * filter, return filtered symbol from filtee. 3828 * 3829 * The symbol's hash value is passed in for efficiency reasons; that 3830 * eliminates many recomputations of the hash value. 3831 */ 3832int 3833symlook_obj(SymLook *req, const Obj_Entry *obj) 3834{ 3835 DoneList donelist; 3836 SymLook req1; 3837 int flags, res, mres; 3838 3839 /* 3840 * If there is at least one valid hash at this point, we prefer to 3841 * use the faster GNU version if available. 3842 */ 3843 if (obj->valid_hash_gnu) 3844 mres = symlook_obj1_gnu(req, obj); 3845 else if (obj->valid_hash_sysv) 3846 mres = symlook_obj1_sysv(req, obj); 3847 else 3848 return (EINVAL); 3849 3850 if (mres == 0) { 3851 if (obj->needed_filtees != NULL) { 3852 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3853 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3854 donelist_init(&donelist); 3855 symlook_init_from_req(&req1, req); 3856 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3857 if (res == 0) { 3858 req->sym_out = req1.sym_out; 3859 req->defobj_out = req1.defobj_out; 3860 } 3861 return (res); 3862 } 3863 if (obj->needed_aux_filtees != NULL) { 3864 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3865 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3866 donelist_init(&donelist); 3867 symlook_init_from_req(&req1, req); 3868 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3869 if (res == 0) { 3870 req->sym_out = req1.sym_out; 3871 req->defobj_out = req1.defobj_out; 3872 return (res); 3873 } 3874 } 3875 } 3876 return (mres); 3877} 3878 3879/* Symbol match routine common to both hash functions */ 3880static bool 3881matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3882 const unsigned long symnum) 3883{ 3884 Elf_Versym verndx; 3885 const Elf_Sym *symp; 3886 const char *strp; 3887 3888 symp = obj->symtab + symnum; 3889 strp = obj->strtab + symp->st_name; 3890 3891 switch (ELF_ST_TYPE(symp->st_info)) { 3892 case STT_FUNC: 3893 case STT_NOTYPE: 3894 case STT_OBJECT: 3895 case STT_COMMON: 3896 case STT_GNU_IFUNC: 3897 if (symp->st_value == 0) 3898 return (false); 3899 /* fallthrough */ 3900 case STT_TLS: 3901 if (symp->st_shndx != SHN_UNDEF) 3902 break; 3903#ifndef __mips__ 3904 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3905 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3906 break; 3907 /* fallthrough */ 3908#endif 3909 default: 3910 return (false); 3911 } 3912 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3913 return (false); 3914 3915 if (req->ventry == NULL) { 3916 if (obj->versyms != NULL) { 3917 verndx = VER_NDX(obj->versyms[symnum]); 3918 if (verndx > obj->vernum) { 3919 _rtld_error( 3920 "%s: symbol %s references wrong version %d", 3921 obj->path, obj->strtab + symnum, verndx); 3922 return (false); 3923 } 3924 /* 3925 * If we are not called from dlsym (i.e. this 3926 * is a normal relocation from unversioned 3927 * binary), accept the symbol immediately if 3928 * it happens to have first version after this 3929 * shared object became versioned. Otherwise, 3930 * if symbol is versioned and not hidden, 3931 * remember it. If it is the only symbol with 3932 * this name exported by the shared object, it 3933 * will be returned as a match by the calling 3934 * function. If symbol is global (verndx < 2) 3935 * accept it unconditionally. 3936 */ 3937 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3938 verndx == VER_NDX_GIVEN) { 3939 result->sym_out = symp; 3940 return (true); 3941 } 3942 else if (verndx >= VER_NDX_GIVEN) { 3943 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3944 == 0) { 3945 if (result->vsymp == NULL) 3946 result->vsymp = symp; 3947 result->vcount++; 3948 } 3949 return (false); 3950 } 3951 } 3952 result->sym_out = symp; 3953 return (true); 3954 } 3955 if (obj->versyms == NULL) { 3956 if (object_match_name(obj, req->ventry->name)) { 3957 _rtld_error("%s: object %s should provide version %s " 3958 "for symbol %s", obj_rtld.path, obj->path, 3959 req->ventry->name, obj->strtab + symnum); 3960 return (false); 3961 } 3962 } else { 3963 verndx = VER_NDX(obj->versyms[symnum]); 3964 if (verndx > obj->vernum) { 3965 _rtld_error("%s: symbol %s references wrong version %d", 3966 obj->path, obj->strtab + symnum, verndx); 3967 return (false); 3968 } 3969 if (obj->vertab[verndx].hash != req->ventry->hash || 3970 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3971 /* 3972 * Version does not match. Look if this is a 3973 * global symbol and if it is not hidden. If 3974 * global symbol (verndx < 2) is available, 3975 * use it. Do not return symbol if we are 3976 * called by dlvsym, because dlvsym looks for 3977 * a specific version and default one is not 3978 * what dlvsym wants. 3979 */ 3980 if ((req->flags & SYMLOOK_DLSYM) || 3981 (verndx >= VER_NDX_GIVEN) || 3982 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3983 return (false); 3984 } 3985 } 3986 result->sym_out = symp; 3987 return (true); 3988} 3989 3990/* 3991 * Search for symbol using SysV hash function. 3992 * obj->buckets is known not to be NULL at this point; the test for this was 3993 * performed with the obj->valid_hash_sysv assignment. 3994 */ 3995static int 3996symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 3997{ 3998 unsigned long symnum; 3999 Sym_Match_Result matchres; 4000 4001 matchres.sym_out = NULL; 4002 matchres.vsymp = NULL; 4003 matchres.vcount = 0; 4004 4005 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4006 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4007 if (symnum >= obj->nchains) 4008 return (ESRCH); /* Bad object */ 4009 4010 if (matched_symbol(req, obj, &matchres, symnum)) { 4011 req->sym_out = matchres.sym_out; 4012 req->defobj_out = obj; 4013 return (0); 4014 } 4015 } 4016 if (matchres.vcount == 1) { 4017 req->sym_out = matchres.vsymp; 4018 req->defobj_out = obj; 4019 return (0); 4020 } 4021 return (ESRCH); 4022} 4023 4024/* Search for symbol using GNU hash function */ 4025static int 4026symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4027{ 4028 Elf_Addr bloom_word; 4029 const Elf32_Word *hashval; 4030 Elf32_Word bucket; 4031 Sym_Match_Result matchres; 4032 unsigned int h1, h2; 4033 unsigned long symnum; 4034 4035 matchres.sym_out = NULL; 4036 matchres.vsymp = NULL; 4037 matchres.vcount = 0; 4038 4039 /* Pick right bitmask word from Bloom filter array */ 4040 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4041 obj->maskwords_bm_gnu]; 4042 4043 /* Calculate modulus word size of gnu hash and its derivative */ 4044 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4045 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4046 4047 /* Filter out the "definitely not in set" queries */ 4048 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4049 return (ESRCH); 4050 4051 /* Locate hash chain and corresponding value element*/ 4052 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4053 if (bucket == 0) 4054 return (ESRCH); 4055 hashval = &obj->chain_zero_gnu[bucket]; 4056 do { 4057 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4058 symnum = hashval - obj->chain_zero_gnu; 4059 if (matched_symbol(req, obj, &matchres, symnum)) { 4060 req->sym_out = matchres.sym_out; 4061 req->defobj_out = obj; 4062 return (0); 4063 } 4064 } 4065 } while ((*hashval++ & 1) == 0); 4066 if (matchres.vcount == 1) { 4067 req->sym_out = matchres.vsymp; 4068 req->defobj_out = obj; 4069 return (0); 4070 } 4071 return (ESRCH); 4072} 4073 4074static void 4075trace_loaded_objects(Obj_Entry *obj) 4076{ 4077 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4078 int c; 4079 4080 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4081 main_local = ""; 4082 4083 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4084 fmt1 = "\t%o => %p (%x)\n"; 4085 4086 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4087 fmt2 = "\t%o (%x)\n"; 4088 4089 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4090 4091 for (; obj; obj = obj->next) { 4092 Needed_Entry *needed; 4093 char *name, *path; 4094 bool is_lib; 4095 4096 if (list_containers && obj->needed != NULL) 4097 rtld_printf("%s:\n", obj->path); 4098 for (needed = obj->needed; needed; needed = needed->next) { 4099 if (needed->obj != NULL) { 4100 if (needed->obj->traced && !list_containers) 4101 continue; 4102 needed->obj->traced = true; 4103 path = needed->obj->path; 4104 } else 4105 path = "not found"; 4106 4107 name = (char *)obj->strtab + needed->name; 4108 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4109 4110 fmt = is_lib ? fmt1 : fmt2; 4111 while ((c = *fmt++) != '\0') { 4112 switch (c) { 4113 default: 4114 rtld_putchar(c); 4115 continue; 4116 case '\\': 4117 switch (c = *fmt) { 4118 case '\0': 4119 continue; 4120 case 'n': 4121 rtld_putchar('\n'); 4122 break; 4123 case 't': 4124 rtld_putchar('\t'); 4125 break; 4126 } 4127 break; 4128 case '%': 4129 switch (c = *fmt) { 4130 case '\0': 4131 continue; 4132 case '%': 4133 default: 4134 rtld_putchar(c); 4135 break; 4136 case 'A': 4137 rtld_putstr(main_local); 4138 break; 4139 case 'a': 4140 rtld_putstr(obj_main->path); 4141 break; 4142 case 'o': 4143 rtld_putstr(name); 4144 break; 4145#if 0 4146 case 'm': 4147 rtld_printf("%d", sodp->sod_major); 4148 break; 4149 case 'n': 4150 rtld_printf("%d", sodp->sod_minor); 4151 break; 4152#endif 4153 case 'p': 4154 rtld_putstr(path); 4155 break; 4156 case 'x': 4157 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4158 0); 4159 break; 4160 } 4161 break; 4162 } 4163 ++fmt; 4164 } 4165 } 4166 } 4167} 4168 4169/* 4170 * Unload a dlopened object and its dependencies from memory and from 4171 * our data structures. It is assumed that the DAG rooted in the 4172 * object has already been unreferenced, and that the object has a 4173 * reference count of 0. 4174 */ 4175static void 4176unload_object(Obj_Entry *root) 4177{ 4178 Obj_Entry *obj; 4179 Obj_Entry **linkp; 4180 4181 assert(root->refcount == 0); 4182 4183 /* 4184 * Pass over the DAG removing unreferenced objects from 4185 * appropriate lists. 4186 */ 4187 unlink_object(root); 4188 4189 /* Unmap all objects that are no longer referenced. */ 4190 linkp = &obj_list->next; 4191 while ((obj = *linkp) != NULL) { 4192 if (obj->refcount == 0) { 4193 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4194 obj->path); 4195 dbg("unloading \"%s\"", obj->path); 4196 unload_filtees(root); 4197 munmap(obj->mapbase, obj->mapsize); 4198 linkmap_delete(obj); 4199 *linkp = obj->next; 4200 obj_count--; 4201 obj_free(obj); 4202 } else 4203 linkp = &obj->next; 4204 } 4205 obj_tail = linkp; 4206} 4207 4208static void 4209unlink_object(Obj_Entry *root) 4210{ 4211 Objlist_Entry *elm; 4212 4213 if (root->refcount == 0) { 4214 /* Remove the object from the RTLD_GLOBAL list. */ 4215 objlist_remove(&list_global, root); 4216 4217 /* Remove the object from all objects' DAG lists. */ 4218 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4219 objlist_remove(&elm->obj->dldags, root); 4220 if (elm->obj != root) 4221 unlink_object(elm->obj); 4222 } 4223 } 4224} 4225 4226static void 4227ref_dag(Obj_Entry *root) 4228{ 4229 Objlist_Entry *elm; 4230 4231 assert(root->dag_inited); 4232 STAILQ_FOREACH(elm, &root->dagmembers, link) 4233 elm->obj->refcount++; 4234} 4235 4236static void 4237unref_dag(Obj_Entry *root) 4238{ 4239 Objlist_Entry *elm; 4240 4241 assert(root->dag_inited); 4242 STAILQ_FOREACH(elm, &root->dagmembers, link) 4243 elm->obj->refcount--; 4244} 4245 4246/* 4247 * Common code for MD __tls_get_addr(). 4248 */ 4249static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4250static void * 4251tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4252{ 4253 Elf_Addr *newdtv, *dtv; 4254 RtldLockState lockstate; 4255 int to_copy; 4256 4257 dtv = *dtvp; 4258 /* Check dtv generation in case new modules have arrived */ 4259 if (dtv[0] != tls_dtv_generation) { 4260 wlock_acquire(rtld_bind_lock, &lockstate); 4261 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4262 to_copy = dtv[1]; 4263 if (to_copy > tls_max_index) 4264 to_copy = tls_max_index; 4265 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4266 newdtv[0] = tls_dtv_generation; 4267 newdtv[1] = tls_max_index; 4268 free(dtv); 4269 lock_release(rtld_bind_lock, &lockstate); 4270 dtv = *dtvp = newdtv; 4271 } 4272 4273 /* Dynamically allocate module TLS if necessary */ 4274 if (dtv[index + 1] == 0) { 4275 /* Signal safe, wlock will block out signals. */ 4276 wlock_acquire(rtld_bind_lock, &lockstate); 4277 if (!dtv[index + 1]) 4278 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4279 lock_release(rtld_bind_lock, &lockstate); 4280 } 4281 return ((void *)(dtv[index + 1] + offset)); 4282} 4283 4284void * 4285tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4286{ 4287 Elf_Addr *dtv; 4288 4289 dtv = *dtvp; 4290 /* Check dtv generation in case new modules have arrived */ 4291 if (__predict_true(dtv[0] == tls_dtv_generation && 4292 dtv[index + 1] != 0)) 4293 return ((void *)(dtv[index + 1] + offset)); 4294 return (tls_get_addr_slow(dtvp, index, offset)); 4295} 4296 4297#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4298 4299/* 4300 * Allocate Static TLS using the Variant I method. 4301 */ 4302void * 4303allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4304{ 4305 Obj_Entry *obj; 4306 char *tcb; 4307 Elf_Addr **tls; 4308 Elf_Addr *dtv; 4309 Elf_Addr addr; 4310 int i; 4311 4312 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4313 return (oldtcb); 4314 4315 assert(tcbsize >= TLS_TCB_SIZE); 4316 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4317 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4318 4319 if (oldtcb != NULL) { 4320 memcpy(tls, oldtcb, tls_static_space); 4321 free(oldtcb); 4322 4323 /* Adjust the DTV. */ 4324 dtv = tls[0]; 4325 for (i = 0; i < dtv[1]; i++) { 4326 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4327 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4328 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4329 } 4330 } 4331 } else { 4332 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4333 tls[0] = dtv; 4334 dtv[0] = tls_dtv_generation; 4335 dtv[1] = tls_max_index; 4336 4337 for (obj = objs; obj; obj = obj->next) { 4338 if (obj->tlsoffset > 0) { 4339 addr = (Elf_Addr)tls + obj->tlsoffset; 4340 if (obj->tlsinitsize > 0) 4341 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4342 if (obj->tlssize > obj->tlsinitsize) 4343 memset((void*) (addr + obj->tlsinitsize), 0, 4344 obj->tlssize - obj->tlsinitsize); 4345 dtv[obj->tlsindex + 1] = addr; 4346 } 4347 } 4348 } 4349 4350 return (tcb); 4351} 4352 4353void 4354free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4355{ 4356 Elf_Addr *dtv; 4357 Elf_Addr tlsstart, tlsend; 4358 int dtvsize, i; 4359 4360 assert(tcbsize >= TLS_TCB_SIZE); 4361 4362 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4363 tlsend = tlsstart + tls_static_space; 4364 4365 dtv = *(Elf_Addr **)tlsstart; 4366 dtvsize = dtv[1]; 4367 for (i = 0; i < dtvsize; i++) { 4368 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4369 free((void*)dtv[i+2]); 4370 } 4371 } 4372 free(dtv); 4373 free(tcb); 4374} 4375 4376#endif 4377 4378#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4379 4380/* 4381 * Allocate Static TLS using the Variant II method. 4382 */ 4383void * 4384allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4385{ 4386 Obj_Entry *obj; 4387 size_t size, ralign; 4388 char *tls; 4389 Elf_Addr *dtv, *olddtv; 4390 Elf_Addr segbase, oldsegbase, addr; 4391 int i; 4392 4393 ralign = tcbalign; 4394 if (tls_static_max_align > ralign) 4395 ralign = tls_static_max_align; 4396 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4397 4398 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4399 tls = malloc_aligned(size, ralign); 4400 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4401 4402 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4403 ((Elf_Addr*)segbase)[0] = segbase; 4404 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4405 4406 dtv[0] = tls_dtv_generation; 4407 dtv[1] = tls_max_index; 4408 4409 if (oldtls) { 4410 /* 4411 * Copy the static TLS block over whole. 4412 */ 4413 oldsegbase = (Elf_Addr) oldtls; 4414 memcpy((void *)(segbase - tls_static_space), 4415 (const void *)(oldsegbase - tls_static_space), 4416 tls_static_space); 4417 4418 /* 4419 * If any dynamic TLS blocks have been created tls_get_addr(), 4420 * move them over. 4421 */ 4422 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4423 for (i = 0; i < olddtv[1]; i++) { 4424 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4425 dtv[i+2] = olddtv[i+2]; 4426 olddtv[i+2] = 0; 4427 } 4428 } 4429 4430 /* 4431 * We assume that this block was the one we created with 4432 * allocate_initial_tls(). 4433 */ 4434 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4435 } else { 4436 for (obj = objs; obj; obj = obj->next) { 4437 if (obj->tlsoffset) { 4438 addr = segbase - obj->tlsoffset; 4439 memset((void*) (addr + obj->tlsinitsize), 4440 0, obj->tlssize - obj->tlsinitsize); 4441 if (obj->tlsinit) 4442 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4443 dtv[obj->tlsindex + 1] = addr; 4444 } 4445 } 4446 } 4447 4448 return (void*) segbase; 4449} 4450 4451void 4452free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4453{ 4454 Elf_Addr* dtv; 4455 size_t size, ralign; 4456 int dtvsize, i; 4457 Elf_Addr tlsstart, tlsend; 4458 4459 /* 4460 * Figure out the size of the initial TLS block so that we can 4461 * find stuff which ___tls_get_addr() allocated dynamically. 4462 */ 4463 ralign = tcbalign; 4464 if (tls_static_max_align > ralign) 4465 ralign = tls_static_max_align; 4466 size = round(tls_static_space, ralign); 4467 4468 dtv = ((Elf_Addr**)tls)[1]; 4469 dtvsize = dtv[1]; 4470 tlsend = (Elf_Addr) tls; 4471 tlsstart = tlsend - size; 4472 for (i = 0; i < dtvsize; i++) { 4473 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4474 free_aligned((void *)dtv[i + 2]); 4475 } 4476 } 4477 4478 free_aligned((void *)tlsstart); 4479 free((void*) dtv); 4480} 4481 4482#endif 4483 4484/* 4485 * Allocate TLS block for module with given index. 4486 */ 4487void * 4488allocate_module_tls(int index) 4489{ 4490 Obj_Entry* obj; 4491 char* p; 4492 4493 for (obj = obj_list; obj; obj = obj->next) { 4494 if (obj->tlsindex == index) 4495 break; 4496 } 4497 if (!obj) { 4498 _rtld_error("Can't find module with TLS index %d", index); 4499 die(); 4500 } 4501 4502 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4503 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4504 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4505 4506 return p; 4507} 4508 4509bool 4510allocate_tls_offset(Obj_Entry *obj) 4511{ 4512 size_t off; 4513 4514 if (obj->tls_done) 4515 return true; 4516 4517 if (obj->tlssize == 0) { 4518 obj->tls_done = true; 4519 return true; 4520 } 4521 4522 if (obj->tlsindex == 1) 4523 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4524 else 4525 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4526 obj->tlssize, obj->tlsalign); 4527 4528 /* 4529 * If we have already fixed the size of the static TLS block, we 4530 * must stay within that size. When allocating the static TLS, we 4531 * leave a small amount of space spare to be used for dynamically 4532 * loading modules which use static TLS. 4533 */ 4534 if (tls_static_space != 0) { 4535 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4536 return false; 4537 } else if (obj->tlsalign > tls_static_max_align) { 4538 tls_static_max_align = obj->tlsalign; 4539 } 4540 4541 tls_last_offset = obj->tlsoffset = off; 4542 tls_last_size = obj->tlssize; 4543 obj->tls_done = true; 4544 4545 return true; 4546} 4547 4548void 4549free_tls_offset(Obj_Entry *obj) 4550{ 4551 4552 /* 4553 * If we were the last thing to allocate out of the static TLS 4554 * block, we give our space back to the 'allocator'. This is a 4555 * simplistic workaround to allow libGL.so.1 to be loaded and 4556 * unloaded multiple times. 4557 */ 4558 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4559 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4560 tls_last_offset -= obj->tlssize; 4561 tls_last_size = 0; 4562 } 4563} 4564 4565void * 4566_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4567{ 4568 void *ret; 4569 RtldLockState lockstate; 4570 4571 wlock_acquire(rtld_bind_lock, &lockstate); 4572 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4573 lock_release(rtld_bind_lock, &lockstate); 4574 return (ret); 4575} 4576 4577void 4578_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4579{ 4580 RtldLockState lockstate; 4581 4582 wlock_acquire(rtld_bind_lock, &lockstate); 4583 free_tls(tcb, tcbsize, tcbalign); 4584 lock_release(rtld_bind_lock, &lockstate); 4585} 4586 4587static void 4588object_add_name(Obj_Entry *obj, const char *name) 4589{ 4590 Name_Entry *entry; 4591 size_t len; 4592 4593 len = strlen(name); 4594 entry = malloc(sizeof(Name_Entry) + len); 4595 4596 if (entry != NULL) { 4597 strcpy(entry->name, name); 4598 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4599 } 4600} 4601 4602static int 4603object_match_name(const Obj_Entry *obj, const char *name) 4604{ 4605 Name_Entry *entry; 4606 4607 STAILQ_FOREACH(entry, &obj->names, link) { 4608 if (strcmp(name, entry->name) == 0) 4609 return (1); 4610 } 4611 return (0); 4612} 4613 4614static Obj_Entry * 4615locate_dependency(const Obj_Entry *obj, const char *name) 4616{ 4617 const Objlist_Entry *entry; 4618 const Needed_Entry *needed; 4619 4620 STAILQ_FOREACH(entry, &list_main, link) { 4621 if (object_match_name(entry->obj, name)) 4622 return entry->obj; 4623 } 4624 4625 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4626 if (strcmp(obj->strtab + needed->name, name) == 0 || 4627 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4628 /* 4629 * If there is DT_NEEDED for the name we are looking for, 4630 * we are all set. Note that object might not be found if 4631 * dependency was not loaded yet, so the function can 4632 * return NULL here. This is expected and handled 4633 * properly by the caller. 4634 */ 4635 return (needed->obj); 4636 } 4637 } 4638 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4639 obj->path, name); 4640 die(); 4641} 4642 4643static int 4644check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4645 const Elf_Vernaux *vna) 4646{ 4647 const Elf_Verdef *vd; 4648 const char *vername; 4649 4650 vername = refobj->strtab + vna->vna_name; 4651 vd = depobj->verdef; 4652 if (vd == NULL) { 4653 _rtld_error("%s: version %s required by %s not defined", 4654 depobj->path, vername, refobj->path); 4655 return (-1); 4656 } 4657 for (;;) { 4658 if (vd->vd_version != VER_DEF_CURRENT) { 4659 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4660 depobj->path, vd->vd_version); 4661 return (-1); 4662 } 4663 if (vna->vna_hash == vd->vd_hash) { 4664 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4665 ((char *)vd + vd->vd_aux); 4666 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4667 return (0); 4668 } 4669 if (vd->vd_next == 0) 4670 break; 4671 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4672 } 4673 if (vna->vna_flags & VER_FLG_WEAK) 4674 return (0); 4675 _rtld_error("%s: version %s required by %s not found", 4676 depobj->path, vername, refobj->path); 4677 return (-1); 4678} 4679 4680static int 4681rtld_verify_object_versions(Obj_Entry *obj) 4682{ 4683 const Elf_Verneed *vn; 4684 const Elf_Verdef *vd; 4685 const Elf_Verdaux *vda; 4686 const Elf_Vernaux *vna; 4687 const Obj_Entry *depobj; 4688 int maxvernum, vernum; 4689 4690 if (obj->ver_checked) 4691 return (0); 4692 obj->ver_checked = true; 4693 4694 maxvernum = 0; 4695 /* 4696 * Walk over defined and required version records and figure out 4697 * max index used by any of them. Do very basic sanity checking 4698 * while there. 4699 */ 4700 vn = obj->verneed; 4701 while (vn != NULL) { 4702 if (vn->vn_version != VER_NEED_CURRENT) { 4703 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4704 obj->path, vn->vn_version); 4705 return (-1); 4706 } 4707 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4708 for (;;) { 4709 vernum = VER_NEED_IDX(vna->vna_other); 4710 if (vernum > maxvernum) 4711 maxvernum = vernum; 4712 if (vna->vna_next == 0) 4713 break; 4714 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4715 } 4716 if (vn->vn_next == 0) 4717 break; 4718 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4719 } 4720 4721 vd = obj->verdef; 4722 while (vd != NULL) { 4723 if (vd->vd_version != VER_DEF_CURRENT) { 4724 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4725 obj->path, vd->vd_version); 4726 return (-1); 4727 } 4728 vernum = VER_DEF_IDX(vd->vd_ndx); 4729 if (vernum > maxvernum) 4730 maxvernum = vernum; 4731 if (vd->vd_next == 0) 4732 break; 4733 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4734 } 4735 4736 if (maxvernum == 0) 4737 return (0); 4738 4739 /* 4740 * Store version information in array indexable by version index. 4741 * Verify that object version requirements are satisfied along the 4742 * way. 4743 */ 4744 obj->vernum = maxvernum + 1; 4745 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4746 4747 vd = obj->verdef; 4748 while (vd != NULL) { 4749 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4750 vernum = VER_DEF_IDX(vd->vd_ndx); 4751 assert(vernum <= maxvernum); 4752 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4753 obj->vertab[vernum].hash = vd->vd_hash; 4754 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4755 obj->vertab[vernum].file = NULL; 4756 obj->vertab[vernum].flags = 0; 4757 } 4758 if (vd->vd_next == 0) 4759 break; 4760 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4761 } 4762 4763 vn = obj->verneed; 4764 while (vn != NULL) { 4765 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4766 if (depobj == NULL) 4767 return (-1); 4768 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4769 for (;;) { 4770 if (check_object_provided_version(obj, depobj, vna)) 4771 return (-1); 4772 vernum = VER_NEED_IDX(vna->vna_other); 4773 assert(vernum <= maxvernum); 4774 obj->vertab[vernum].hash = vna->vna_hash; 4775 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4776 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4777 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4778 VER_INFO_HIDDEN : 0; 4779 if (vna->vna_next == 0) 4780 break; 4781 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4782 } 4783 if (vn->vn_next == 0) 4784 break; 4785 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4786 } 4787 return 0; 4788} 4789 4790static int 4791rtld_verify_versions(const Objlist *objlist) 4792{ 4793 Objlist_Entry *entry; 4794 int rc; 4795 4796 rc = 0; 4797 STAILQ_FOREACH(entry, objlist, link) { 4798 /* 4799 * Skip dummy objects or objects that have their version requirements 4800 * already checked. 4801 */ 4802 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4803 continue; 4804 if (rtld_verify_object_versions(entry->obj) == -1) { 4805 rc = -1; 4806 if (ld_tracing == NULL) 4807 break; 4808 } 4809 } 4810 if (rc == 0 || ld_tracing != NULL) 4811 rc = rtld_verify_object_versions(&obj_rtld); 4812 return rc; 4813} 4814 4815const Ver_Entry * 4816fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4817{ 4818 Elf_Versym vernum; 4819 4820 if (obj->vertab) { 4821 vernum = VER_NDX(obj->versyms[symnum]); 4822 if (vernum >= obj->vernum) { 4823 _rtld_error("%s: symbol %s has wrong verneed value %d", 4824 obj->path, obj->strtab + symnum, vernum); 4825 } else if (obj->vertab[vernum].hash != 0) { 4826 return &obj->vertab[vernum]; 4827 } 4828 } 4829 return NULL; 4830} 4831 4832int 4833_rtld_get_stack_prot(void) 4834{ 4835 4836 return (stack_prot); 4837} 4838 4839int 4840_rtld_is_dlopened(void *arg) 4841{ 4842 Obj_Entry *obj; 4843 RtldLockState lockstate; 4844 int res; 4845 4846 rlock_acquire(rtld_bind_lock, &lockstate); 4847 obj = dlcheck(arg); 4848 if (obj == NULL) 4849 obj = obj_from_addr(arg); 4850 if (obj == NULL) { 4851 _rtld_error("No shared object contains address"); 4852 lock_release(rtld_bind_lock, &lockstate); 4853 return (-1); 4854 } 4855 res = obj->dlopened ? 1 : 0; 4856 lock_release(rtld_bind_lock, &lockstate); 4857 return (res); 4858} 4859 4860static void 4861map_stacks_exec(RtldLockState *lockstate) 4862{ 4863 void (*thr_map_stacks_exec)(void); 4864 4865 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4866 return; 4867 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4868 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4869 if (thr_map_stacks_exec != NULL) { 4870 stack_prot |= PROT_EXEC; 4871 thr_map_stacks_exec(); 4872 } 4873} 4874 4875void 4876symlook_init(SymLook *dst, const char *name) 4877{ 4878 4879 bzero(dst, sizeof(*dst)); 4880 dst->name = name; 4881 dst->hash = elf_hash(name); 4882 dst->hash_gnu = gnu_hash(name); 4883} 4884 4885static void 4886symlook_init_from_req(SymLook *dst, const SymLook *src) 4887{ 4888 4889 dst->name = src->name; 4890 dst->hash = src->hash; 4891 dst->hash_gnu = src->hash_gnu; 4892 dst->ventry = src->ventry; 4893 dst->flags = src->flags; 4894 dst->defobj_out = NULL; 4895 dst->sym_out = NULL; 4896 dst->lockstate = src->lockstate; 4897} 4898 4899/* 4900 * Overrides for libc_pic-provided functions. 4901 */ 4902 4903int 4904__getosreldate(void) 4905{ 4906 size_t len; 4907 int oid[2]; 4908 int error, osrel; 4909 4910 if (osreldate != 0) 4911 return (osreldate); 4912 4913 oid[0] = CTL_KERN; 4914 oid[1] = KERN_OSRELDATE; 4915 osrel = 0; 4916 len = sizeof(osrel); 4917 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4918 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4919 osreldate = osrel; 4920 return (osreldate); 4921} 4922 4923void 4924exit(int status) 4925{ 4926 4927 _exit(status); 4928} 4929 4930void (*__cleanup)(void); 4931int __isthreaded = 0; 4932int _thread_autoinit_dummy_decl = 1; 4933 4934/* 4935 * No unresolved symbols for rtld. 4936 */ 4937void 4938__pthread_cxa_finalize(struct dl_phdr_info *a) 4939{ 4940} 4941 4942void 4943__stack_chk_fail(void) 4944{ 4945 4946 _rtld_error("stack overflow detected; terminated"); 4947 die(); 4948} 4949__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4950 4951void 4952__chk_fail(void) 4953{ 4954 4955 _rtld_error("buffer overflow detected; terminated"); 4956 die(); 4957} 4958 4959const char * 4960rtld_strerror(int errnum) 4961{ 4962 4963 if (errnum < 0 || errnum >= sys_nerr) 4964 return ("Unknown error"); 4965 return (sys_errlist[errnum]); 4966} 4967