rtld.c revision 281486
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 281486 2015-04-13 08:35:03Z peter $ 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 XXX ;*/ 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_nodelete(Obj_Entry *root) 1779{ 1780 const Objlist_Entry *elm; 1781 1782 /* 1783 * Walk over object DAG and process every dependent object that 1784 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1785 * which then should have its reference upped separately. 1786 */ 1787 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1788 if (elm->obj != NULL && elm->obj->z_nodelete && 1789 !elm->obj->ref_nodel) { 1790 dbg("obj %s nodelete", elm->obj->path); 1791 init_dag(elm->obj); 1792 ref_dag(elm->obj); 1793 elm->obj->ref_nodel = true; 1794 } 1795 } 1796} 1797/* 1798 * Initialize the dynamic linker. The argument is the address at which 1799 * the dynamic linker has been mapped into memory. The primary task of 1800 * this function is to relocate the dynamic linker. 1801 */ 1802static void 1803init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1804{ 1805 Obj_Entry objtmp; /* Temporary rtld object */ 1806 const Elf_Dyn *dyn_rpath; 1807 const Elf_Dyn *dyn_soname; 1808 const Elf_Dyn *dyn_runpath; 1809 1810#ifdef RTLD_INIT_PAGESIZES_EARLY 1811 /* The page size is required by the dynamic memory allocator. */ 1812 init_pagesizes(aux_info); 1813#endif 1814 1815 /* 1816 * Conjure up an Obj_Entry structure for the dynamic linker. 1817 * 1818 * The "path" member can't be initialized yet because string constants 1819 * cannot yet be accessed. Below we will set it correctly. 1820 */ 1821 memset(&objtmp, 0, sizeof(objtmp)); 1822 objtmp.path = NULL; 1823 objtmp.rtld = true; 1824 objtmp.mapbase = mapbase; 1825#ifdef PIC 1826 objtmp.relocbase = mapbase; 1827#endif 1828 if (RTLD_IS_DYNAMIC()) { 1829 objtmp.dynamic = rtld_dynamic(&objtmp); 1830 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1831 assert(objtmp.needed == NULL); 1832#if !defined(__mips__) 1833 /* MIPS has a bogus DT_TEXTREL. */ 1834 assert(!objtmp.textrel); 1835#endif 1836 1837 /* 1838 * Temporarily put the dynamic linker entry into the object list, so 1839 * that symbols can be found. 1840 */ 1841 1842 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1843 } 1844 1845 /* Initialize the object list. */ 1846 obj_tail = &obj_list; 1847 1848 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1849 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1850 1851#ifndef RTLD_INIT_PAGESIZES_EARLY 1852 /* The page size is required by the dynamic memory allocator. */ 1853 init_pagesizes(aux_info); 1854#endif 1855 1856 if (aux_info[AT_OSRELDATE] != NULL) 1857 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1858 1859 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1860 1861 /* Replace the path with a dynamically allocated copy. */ 1862 obj_rtld.path = xstrdup(PATH_RTLD); 1863 1864 r_debug.r_brk = r_debug_state; 1865 r_debug.r_state = RT_CONSISTENT; 1866} 1867 1868/* 1869 * Retrieve the array of supported page sizes. The kernel provides the page 1870 * sizes in increasing order. 1871 */ 1872static void 1873init_pagesizes(Elf_Auxinfo **aux_info) 1874{ 1875 static size_t psa[MAXPAGESIZES]; 1876 int mib[2]; 1877 size_t len, size; 1878 1879 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1880 NULL) { 1881 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1882 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1883 } else { 1884 len = 2; 1885 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1886 size = sizeof(psa); 1887 else { 1888 /* As a fallback, retrieve the base page size. */ 1889 size = sizeof(psa[0]); 1890 if (aux_info[AT_PAGESZ] != NULL) { 1891 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1892 goto psa_filled; 1893 } else { 1894 mib[0] = CTL_HW; 1895 mib[1] = HW_PAGESIZE; 1896 len = 2; 1897 } 1898 } 1899 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1900 _rtld_error("sysctl for hw.pagesize(s) failed"); 1901 die(); 1902 } 1903psa_filled: 1904 pagesizes = psa; 1905 } 1906 npagesizes = size / sizeof(pagesizes[0]); 1907 /* Discard any invalid entries at the end of the array. */ 1908 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1909 npagesizes--; 1910} 1911 1912/* 1913 * Add the init functions from a needed object list (and its recursive 1914 * needed objects) to "list". This is not used directly; it is a helper 1915 * function for initlist_add_objects(). The write lock must be held 1916 * when this function is called. 1917 */ 1918static void 1919initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1920{ 1921 /* Recursively process the successor needed objects. */ 1922 if (needed->next != NULL) 1923 initlist_add_neededs(needed->next, list); 1924 1925 /* Process the current needed object. */ 1926 if (needed->obj != NULL) 1927 initlist_add_objects(needed->obj, &needed->obj->next, list); 1928} 1929 1930/* 1931 * Scan all of the DAGs rooted in the range of objects from "obj" to 1932 * "tail" and add their init functions to "list". This recurses over 1933 * the DAGs and ensure the proper init ordering such that each object's 1934 * needed libraries are initialized before the object itself. At the 1935 * same time, this function adds the objects to the global finalization 1936 * list "list_fini" in the opposite order. The write lock must be 1937 * held when this function is called. 1938 */ 1939static void 1940initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1941{ 1942 1943 if (obj->init_scanned || obj->init_done) 1944 return; 1945 obj->init_scanned = true; 1946 1947 /* Recursively process the successor objects. */ 1948 if (&obj->next != tail) 1949 initlist_add_objects(obj->next, tail, list); 1950 1951 /* Recursively process the needed objects. */ 1952 if (obj->needed != NULL) 1953 initlist_add_neededs(obj->needed, list); 1954 if (obj->needed_filtees != NULL) 1955 initlist_add_neededs(obj->needed_filtees, list); 1956 if (obj->needed_aux_filtees != NULL) 1957 initlist_add_neededs(obj->needed_aux_filtees, list); 1958 1959 /* Add the object to the init list. */ 1960 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1961 obj->init_array != (Elf_Addr)NULL) 1962 objlist_push_tail(list, obj); 1963 1964 /* Add the object to the global fini list in the reverse order. */ 1965 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1966 && !obj->on_fini_list) { 1967 objlist_push_head(&list_fini, obj); 1968 obj->on_fini_list = true; 1969 } 1970} 1971 1972#ifndef FPTR_TARGET 1973#define FPTR_TARGET(f) ((Elf_Addr) (f)) 1974#endif 1975 1976static void 1977free_needed_filtees(Needed_Entry *n) 1978{ 1979 Needed_Entry *needed, *needed1; 1980 1981 for (needed = n; needed != NULL; needed = needed->next) { 1982 if (needed->obj != NULL) { 1983 dlclose(needed->obj); 1984 needed->obj = NULL; 1985 } 1986 } 1987 for (needed = n; needed != NULL; needed = needed1) { 1988 needed1 = needed->next; 1989 free(needed); 1990 } 1991} 1992 1993static void 1994unload_filtees(Obj_Entry *obj) 1995{ 1996 1997 free_needed_filtees(obj->needed_filtees); 1998 obj->needed_filtees = NULL; 1999 free_needed_filtees(obj->needed_aux_filtees); 2000 obj->needed_aux_filtees = NULL; 2001 obj->filtees_loaded = false; 2002} 2003 2004static void 2005load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2006 RtldLockState *lockstate) 2007{ 2008 2009 for (; needed != NULL; needed = needed->next) { 2010 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2011 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2012 RTLD_LOCAL, lockstate); 2013 } 2014} 2015 2016static void 2017load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2018{ 2019 2020 lock_restart_for_upgrade(lockstate); 2021 if (!obj->filtees_loaded) { 2022 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2023 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2024 obj->filtees_loaded = true; 2025 } 2026} 2027 2028static int 2029process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2030{ 2031 Obj_Entry *obj1; 2032 2033 for (; needed != NULL; needed = needed->next) { 2034 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2035 flags & ~RTLD_LO_NOLOAD); 2036 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2037 return (-1); 2038 } 2039 return (0); 2040} 2041 2042/* 2043 * Given a shared object, traverse its list of needed objects, and load 2044 * each of them. Returns 0 on success. Generates an error message and 2045 * returns -1 on failure. 2046 */ 2047static int 2048load_needed_objects(Obj_Entry *first, int flags) 2049{ 2050 Obj_Entry *obj; 2051 2052 for (obj = first; obj != NULL; obj = obj->next) { 2053 if (process_needed(obj, obj->needed, flags) == -1) 2054 return (-1); 2055 } 2056 return (0); 2057} 2058 2059static int 2060load_preload_objects(void) 2061{ 2062 char *p = ld_preload; 2063 Obj_Entry *obj; 2064 static const char delim[] = " \t:;"; 2065 2066 if (p == NULL) 2067 return 0; 2068 2069 p += strspn(p, delim); 2070 while (*p != '\0') { 2071 size_t len = strcspn(p, delim); 2072 char savech; 2073 2074 savech = p[len]; 2075 p[len] = '\0'; 2076 obj = load_object(p, -1, NULL, 0); 2077 if (obj == NULL) 2078 return -1; /* XXX - cleanup */ 2079 obj->z_interpose = true; 2080 p[len] = savech; 2081 p += len; 2082 p += strspn(p, delim); 2083 } 2084 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2085 return 0; 2086} 2087 2088static const char * 2089printable_path(const char *path) 2090{ 2091 2092 return (path == NULL ? "<unknown>" : path); 2093} 2094 2095/* 2096 * Load a shared object into memory, if it is not already loaded. The 2097 * object may be specified by name or by user-supplied file descriptor 2098 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2099 * duplicate is. 2100 * 2101 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2102 * on failure. 2103 */ 2104static Obj_Entry * 2105load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2106{ 2107 Obj_Entry *obj; 2108 int fd; 2109 struct stat sb; 2110 char *path; 2111 2112 if (name != NULL) { 2113 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2114 if (object_match_name(obj, name)) 2115 return (obj); 2116 } 2117 2118 path = find_library(name, refobj); 2119 if (path == NULL) 2120 return (NULL); 2121 } else 2122 path = NULL; 2123 2124 /* 2125 * If we didn't find a match by pathname, or the name is not 2126 * supplied, open the file and check again by device and inode. 2127 * This avoids false mismatches caused by multiple links or ".." 2128 * in pathnames. 2129 * 2130 * To avoid a race, we open the file and use fstat() rather than 2131 * using stat(). 2132 */ 2133 fd = -1; 2134 if (fd_u == -1) { 2135 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2136 _rtld_error("Cannot open \"%s\"", path); 2137 free(path); 2138 return (NULL); 2139 } 2140 } else { 2141 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2142 if (fd == -1) { 2143 _rtld_error("Cannot dup fd"); 2144 free(path); 2145 return (NULL); 2146 } 2147 } 2148 if (fstat(fd, &sb) == -1) { 2149 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2150 close(fd); 2151 free(path); 2152 return NULL; 2153 } 2154 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2155 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2156 break; 2157 if (obj != NULL && name != NULL) { 2158 object_add_name(obj, name); 2159 free(path); 2160 close(fd); 2161 return obj; 2162 } 2163 if (flags & RTLD_LO_NOLOAD) { 2164 free(path); 2165 close(fd); 2166 return (NULL); 2167 } 2168 2169 /* First use of this object, so we must map it in */ 2170 obj = do_load_object(fd, name, path, &sb, flags); 2171 if (obj == NULL) 2172 free(path); 2173 close(fd); 2174 2175 return obj; 2176} 2177 2178static Obj_Entry * 2179do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2180 int flags) 2181{ 2182 Obj_Entry *obj; 2183 struct statfs fs; 2184 2185 /* 2186 * but first, make sure that environment variables haven't been 2187 * used to circumvent the noexec flag on a filesystem. 2188 */ 2189 if (dangerous_ld_env) { 2190 if (fstatfs(fd, &fs) != 0) { 2191 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2192 return NULL; 2193 } 2194 if (fs.f_flags & MNT_NOEXEC) { 2195 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2196 return NULL; 2197 } 2198 } 2199 dbg("loading \"%s\"", printable_path(path)); 2200 obj = map_object(fd, printable_path(path), sbp); 2201 if (obj == NULL) 2202 return NULL; 2203 2204 /* 2205 * If DT_SONAME is present in the object, digest_dynamic2 already 2206 * added it to the object names. 2207 */ 2208 if (name != NULL) 2209 object_add_name(obj, name); 2210 obj->path = path; 2211 digest_dynamic(obj, 0); 2212 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2213 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2214 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2215 RTLD_LO_DLOPEN) { 2216 dbg("refusing to load non-loadable \"%s\"", obj->path); 2217 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2218 munmap(obj->mapbase, obj->mapsize); 2219 obj_free(obj); 2220 return (NULL); 2221 } 2222 2223 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2224 *obj_tail = obj; 2225 obj_tail = &obj->next; 2226 obj_count++; 2227 obj_loads++; 2228 linkmap_add(obj); /* for GDB & dlinfo() */ 2229 max_stack_flags |= obj->stack_flags; 2230 2231 dbg(" %p .. %p: %s", obj->mapbase, 2232 obj->mapbase + obj->mapsize - 1, obj->path); 2233 if (obj->textrel) 2234 dbg(" WARNING: %s has impure text", obj->path); 2235 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2236 obj->path); 2237 2238 return obj; 2239} 2240 2241static Obj_Entry * 2242obj_from_addr(const void *addr) 2243{ 2244 Obj_Entry *obj; 2245 2246 for (obj = obj_list; obj != NULL; obj = obj->next) { 2247 if (addr < (void *) obj->mapbase) 2248 continue; 2249 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2250 return obj; 2251 } 2252 return NULL; 2253} 2254 2255static void 2256preinit_main(void) 2257{ 2258 Elf_Addr *preinit_addr; 2259 int index; 2260 2261 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2262 if (preinit_addr == NULL) 2263 return; 2264 2265 for (index = 0; index < obj_main->preinit_array_num; index++) { 2266 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2267 dbg("calling preinit function for %s at %p", obj_main->path, 2268 (void *)preinit_addr[index]); 2269 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2270 0, 0, obj_main->path); 2271 call_init_pointer(obj_main, preinit_addr[index]); 2272 } 2273 } 2274} 2275 2276/* 2277 * Call the finalization functions for each of the objects in "list" 2278 * belonging to the DAG of "root" and referenced once. If NULL "root" 2279 * is specified, every finalization function will be called regardless 2280 * of the reference count and the list elements won't be freed. All of 2281 * the objects are expected to have non-NULL fini functions. 2282 */ 2283static void 2284objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2285{ 2286 Objlist_Entry *elm; 2287 char *saved_msg; 2288 Elf_Addr *fini_addr; 2289 int index; 2290 2291 assert(root == NULL || root->refcount == 1); 2292 2293 /* 2294 * Preserve the current error message since a fini function might 2295 * call into the dynamic linker and overwrite it. 2296 */ 2297 saved_msg = errmsg_save(); 2298 do { 2299 STAILQ_FOREACH(elm, list, link) { 2300 if (root != NULL && (elm->obj->refcount != 1 || 2301 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2302 continue; 2303 /* Remove object from fini list to prevent recursive invocation. */ 2304 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2305 /* 2306 * XXX: If a dlopen() call references an object while the 2307 * fini function is in progress, we might end up trying to 2308 * unload the referenced object in dlclose() or the object 2309 * won't be unloaded although its fini function has been 2310 * called. 2311 */ 2312 lock_release(rtld_bind_lock, lockstate); 2313 2314 /* 2315 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2316 * When this happens, DT_FINI_ARRAY is processed first. 2317 */ 2318 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2319 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2320 for (index = elm->obj->fini_array_num - 1; index >= 0; 2321 index--) { 2322 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2323 dbg("calling fini function for %s at %p", 2324 elm->obj->path, (void *)fini_addr[index]); 2325 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2326 (void *)fini_addr[index], 0, 0, elm->obj->path); 2327 call_initfini_pointer(elm->obj, fini_addr[index]); 2328 } 2329 } 2330 } 2331 if (elm->obj->fini != (Elf_Addr)NULL) { 2332 dbg("calling fini function for %s at %p", elm->obj->path, 2333 (void *)elm->obj->fini); 2334 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2335 0, 0, elm->obj->path); 2336 call_initfini_pointer(elm->obj, elm->obj->fini); 2337 } 2338 wlock_acquire(rtld_bind_lock, lockstate); 2339 /* No need to free anything if process is going down. */ 2340 if (root != NULL) 2341 free(elm); 2342 /* 2343 * We must restart the list traversal after every fini call 2344 * because a dlclose() call from the fini function or from 2345 * another thread might have modified the reference counts. 2346 */ 2347 break; 2348 } 2349 } while (elm != NULL); 2350 errmsg_restore(saved_msg); 2351} 2352 2353/* 2354 * Call the initialization functions for each of the objects in 2355 * "list". All of the objects are expected to have non-NULL init 2356 * functions. 2357 */ 2358static void 2359objlist_call_init(Objlist *list, RtldLockState *lockstate) 2360{ 2361 Objlist_Entry *elm; 2362 Obj_Entry *obj; 2363 char *saved_msg; 2364 Elf_Addr *init_addr; 2365 int index; 2366 2367 /* 2368 * Clean init_scanned flag so that objects can be rechecked and 2369 * possibly initialized earlier if any of vectors called below 2370 * cause the change by using dlopen. 2371 */ 2372 for (obj = obj_list; obj != NULL; obj = obj->next) 2373 obj->init_scanned = false; 2374 2375 /* 2376 * Preserve the current error message since an init function might 2377 * call into the dynamic linker and overwrite it. 2378 */ 2379 saved_msg = errmsg_save(); 2380 STAILQ_FOREACH(elm, list, link) { 2381 if (elm->obj->init_done) /* Initialized early. */ 2382 continue; 2383 /* 2384 * Race: other thread might try to use this object before current 2385 * one completes the initilization. Not much can be done here 2386 * without better locking. 2387 */ 2388 elm->obj->init_done = true; 2389 lock_release(rtld_bind_lock, lockstate); 2390 2391 /* 2392 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2393 * When this happens, DT_INIT is processed first. 2394 */ 2395 if (elm->obj->init != (Elf_Addr)NULL) { 2396 dbg("calling init function for %s at %p", elm->obj->path, 2397 (void *)elm->obj->init); 2398 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2399 0, 0, elm->obj->path); 2400 call_initfini_pointer(elm->obj, elm->obj->init); 2401 } 2402 init_addr = (Elf_Addr *)elm->obj->init_array; 2403 if (init_addr != NULL) { 2404 for (index = 0; index < elm->obj->init_array_num; index++) { 2405 if (init_addr[index] != 0 && init_addr[index] != 1) { 2406 dbg("calling init function for %s at %p", elm->obj->path, 2407 (void *)init_addr[index]); 2408 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2409 (void *)init_addr[index], 0, 0, elm->obj->path); 2410 call_init_pointer(elm->obj, init_addr[index]); 2411 } 2412 } 2413 } 2414 wlock_acquire(rtld_bind_lock, lockstate); 2415 } 2416 errmsg_restore(saved_msg); 2417} 2418 2419static void 2420objlist_clear(Objlist *list) 2421{ 2422 Objlist_Entry *elm; 2423 2424 while (!STAILQ_EMPTY(list)) { 2425 elm = STAILQ_FIRST(list); 2426 STAILQ_REMOVE_HEAD(list, link); 2427 free(elm); 2428 } 2429} 2430 2431static Objlist_Entry * 2432objlist_find(Objlist *list, const Obj_Entry *obj) 2433{ 2434 Objlist_Entry *elm; 2435 2436 STAILQ_FOREACH(elm, list, link) 2437 if (elm->obj == obj) 2438 return elm; 2439 return NULL; 2440} 2441 2442static void 2443objlist_init(Objlist *list) 2444{ 2445 STAILQ_INIT(list); 2446} 2447 2448static void 2449objlist_push_head(Objlist *list, Obj_Entry *obj) 2450{ 2451 Objlist_Entry *elm; 2452 2453 elm = NEW(Objlist_Entry); 2454 elm->obj = obj; 2455 STAILQ_INSERT_HEAD(list, elm, link); 2456} 2457 2458static void 2459objlist_push_tail(Objlist *list, Obj_Entry *obj) 2460{ 2461 Objlist_Entry *elm; 2462 2463 elm = NEW(Objlist_Entry); 2464 elm->obj = obj; 2465 STAILQ_INSERT_TAIL(list, elm, link); 2466} 2467 2468static void 2469objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2470{ 2471 Objlist_Entry *elm, *listelm; 2472 2473 STAILQ_FOREACH(listelm, list, link) { 2474 if (listelm->obj == listobj) 2475 break; 2476 } 2477 elm = NEW(Objlist_Entry); 2478 elm->obj = obj; 2479 if (listelm != NULL) 2480 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2481 else 2482 STAILQ_INSERT_TAIL(list, elm, link); 2483} 2484 2485static void 2486objlist_remove(Objlist *list, Obj_Entry *obj) 2487{ 2488 Objlist_Entry *elm; 2489 2490 if ((elm = objlist_find(list, obj)) != NULL) { 2491 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2492 free(elm); 2493 } 2494} 2495 2496/* 2497 * Relocate dag rooted in the specified object. 2498 * Returns 0 on success, or -1 on failure. 2499 */ 2500 2501static int 2502relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2503 int flags, RtldLockState *lockstate) 2504{ 2505 Objlist_Entry *elm; 2506 int error; 2507 2508 error = 0; 2509 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2510 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2511 lockstate); 2512 if (error == -1) 2513 break; 2514 } 2515 return (error); 2516} 2517 2518/* 2519 * Relocate single object. 2520 * Returns 0 on success, or -1 on failure. 2521 */ 2522static int 2523relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2524 int flags, RtldLockState *lockstate) 2525{ 2526 2527 if (obj->relocated) 2528 return (0); 2529 obj->relocated = true; 2530 if (obj != rtldobj) 2531 dbg("relocating \"%s\"", obj->path); 2532 2533 if (obj->symtab == NULL || obj->strtab == NULL || 2534 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2535 _rtld_error("%s: Shared object has no run-time symbol table", 2536 obj->path); 2537 return (-1); 2538 } 2539 2540 if (obj->textrel) { 2541 /* There are relocations to the write-protected text segment. */ 2542 if (mprotect(obj->mapbase, obj->textsize, 2543 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2544 _rtld_error("%s: Cannot write-enable text segment: %s", 2545 obj->path, rtld_strerror(errno)); 2546 return (-1); 2547 } 2548 } 2549 2550 /* Process the non-PLT non-IFUNC relocations. */ 2551 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2552 return (-1); 2553 2554 if (obj->textrel) { /* Re-protected the text segment. */ 2555 if (mprotect(obj->mapbase, obj->textsize, 2556 PROT_READ|PROT_EXEC) == -1) { 2557 _rtld_error("%s: Cannot write-protect text segment: %s", 2558 obj->path, rtld_strerror(errno)); 2559 return (-1); 2560 } 2561 } 2562 2563 /* Set the special PLT or GOT entries. */ 2564 init_pltgot(obj); 2565 2566 /* Process the PLT relocations. */ 2567 if (reloc_plt(obj) == -1) 2568 return (-1); 2569 /* Relocate the jump slots if we are doing immediate binding. */ 2570 if (obj->bind_now || bind_now) 2571 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2572 return (-1); 2573 2574 /* 2575 * Process the non-PLT IFUNC relocations. The relocations are 2576 * processed in two phases, because IFUNC resolvers may 2577 * reference other symbols, which must be readily processed 2578 * before resolvers are called. 2579 */ 2580 if (obj->non_plt_gnu_ifunc && 2581 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2582 return (-1); 2583 2584 if (obj->relro_size > 0) { 2585 if (mprotect(obj->relro_page, obj->relro_size, 2586 PROT_READ) == -1) { 2587 _rtld_error("%s: Cannot enforce relro protection: %s", 2588 obj->path, rtld_strerror(errno)); 2589 return (-1); 2590 } 2591 } 2592 2593 /* 2594 * Set up the magic number and version in the Obj_Entry. These 2595 * were checked in the crt1.o from the original ElfKit, so we 2596 * set them for backward compatibility. 2597 */ 2598 obj->magic = RTLD_MAGIC; 2599 obj->version = RTLD_VERSION; 2600 2601 return (0); 2602} 2603 2604/* 2605 * Relocate newly-loaded shared objects. The argument is a pointer to 2606 * the Obj_Entry for the first such object. All objects from the first 2607 * to the end of the list of objects are relocated. Returns 0 on success, 2608 * or -1 on failure. 2609 */ 2610static int 2611relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2612 int flags, RtldLockState *lockstate) 2613{ 2614 Obj_Entry *obj; 2615 int error; 2616 2617 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2618 error = relocate_object(obj, bind_now, rtldobj, flags, 2619 lockstate); 2620 if (error == -1) 2621 break; 2622 } 2623 return (error); 2624} 2625 2626/* 2627 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2628 * referencing STT_GNU_IFUNC symbols is postponed till the other 2629 * relocations are done. The indirect functions specified as 2630 * ifunc are allowed to call other symbols, so we need to have 2631 * objects relocated before asking for resolution from indirects. 2632 * 2633 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2634 * instead of the usual lazy handling of PLT slots. It is 2635 * consistent with how GNU does it. 2636 */ 2637static int 2638resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2639 RtldLockState *lockstate) 2640{ 2641 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2642 return (-1); 2643 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2644 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2645 return (-1); 2646 return (0); 2647} 2648 2649static int 2650resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2651 RtldLockState *lockstate) 2652{ 2653 Obj_Entry *obj; 2654 2655 for (obj = first; obj != NULL; obj = obj->next) { 2656 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2657 return (-1); 2658 } 2659 return (0); 2660} 2661 2662static int 2663initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2664 RtldLockState *lockstate) 2665{ 2666 Objlist_Entry *elm; 2667 2668 STAILQ_FOREACH(elm, list, link) { 2669 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2670 lockstate) == -1) 2671 return (-1); 2672 } 2673 return (0); 2674} 2675 2676/* 2677 * Cleanup procedure. It will be called (by the atexit mechanism) just 2678 * before the process exits. 2679 */ 2680static void 2681rtld_exit(void) 2682{ 2683 RtldLockState lockstate; 2684 2685 wlock_acquire(rtld_bind_lock, &lockstate); 2686 dbg("rtld_exit()"); 2687 objlist_call_fini(&list_fini, NULL, &lockstate); 2688 /* No need to remove the items from the list, since we are exiting. */ 2689 if (!libmap_disable) 2690 lm_fini(); 2691 lock_release(rtld_bind_lock, &lockstate); 2692} 2693 2694/* 2695 * Iterate over a search path, translate each element, and invoke the 2696 * callback on the result. 2697 */ 2698static void * 2699path_enumerate(const char *path, path_enum_proc callback, void *arg) 2700{ 2701 const char *trans; 2702 if (path == NULL) 2703 return (NULL); 2704 2705 path += strspn(path, ":;"); 2706 while (*path != '\0') { 2707 size_t len; 2708 char *res; 2709 2710 len = strcspn(path, ":;"); 2711 trans = lm_findn(NULL, path, len); 2712 if (trans) 2713 res = callback(trans, strlen(trans), arg); 2714 else 2715 res = callback(path, len, arg); 2716 2717 if (res != NULL) 2718 return (res); 2719 2720 path += len; 2721 path += strspn(path, ":;"); 2722 } 2723 2724 return (NULL); 2725} 2726 2727struct try_library_args { 2728 const char *name; 2729 size_t namelen; 2730 char *buffer; 2731 size_t buflen; 2732}; 2733 2734static void * 2735try_library_path(const char *dir, size_t dirlen, void *param) 2736{ 2737 struct try_library_args *arg; 2738 2739 arg = param; 2740 if (*dir == '/' || trust) { 2741 char *pathname; 2742 2743 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2744 return (NULL); 2745 2746 pathname = arg->buffer; 2747 strncpy(pathname, dir, dirlen); 2748 pathname[dirlen] = '/'; 2749 strcpy(pathname + dirlen + 1, arg->name); 2750 2751 dbg(" Trying \"%s\"", pathname); 2752 if (access(pathname, F_OK) == 0) { /* We found it */ 2753 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2754 strcpy(pathname, arg->buffer); 2755 return (pathname); 2756 } 2757 } 2758 return (NULL); 2759} 2760 2761static char * 2762search_library_path(const char *name, const char *path) 2763{ 2764 char *p; 2765 struct try_library_args arg; 2766 2767 if (path == NULL) 2768 return NULL; 2769 2770 arg.name = name; 2771 arg.namelen = strlen(name); 2772 arg.buffer = xmalloc(PATH_MAX); 2773 arg.buflen = PATH_MAX; 2774 2775 p = path_enumerate(path, try_library_path, &arg); 2776 2777 free(arg.buffer); 2778 2779 return (p); 2780} 2781 2782int 2783dlclose(void *handle) 2784{ 2785 Obj_Entry *root; 2786 RtldLockState lockstate; 2787 2788 wlock_acquire(rtld_bind_lock, &lockstate); 2789 root = dlcheck(handle); 2790 if (root == NULL) { 2791 lock_release(rtld_bind_lock, &lockstate); 2792 return -1; 2793 } 2794 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2795 root->path); 2796 2797 /* Unreference the object and its dependencies. */ 2798 root->dl_refcount--; 2799 2800 if (root->refcount == 1) { 2801 /* 2802 * The object will be no longer referenced, so we must unload it. 2803 * First, call the fini functions. 2804 */ 2805 objlist_call_fini(&list_fini, root, &lockstate); 2806 2807 unref_dag(root); 2808 2809 /* Finish cleaning up the newly-unreferenced objects. */ 2810 GDB_STATE(RT_DELETE,&root->linkmap); 2811 unload_object(root); 2812 GDB_STATE(RT_CONSISTENT,NULL); 2813 } else 2814 unref_dag(root); 2815 2816 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2817 lock_release(rtld_bind_lock, &lockstate); 2818 return 0; 2819} 2820 2821char * 2822dlerror(void) 2823{ 2824 char *msg = error_message; 2825 error_message = NULL; 2826 return msg; 2827} 2828 2829/* 2830 * This function is deprecated and has no effect. 2831 */ 2832void 2833dllockinit(void *context, 2834 void *(*lock_create)(void *context), 2835 void (*rlock_acquire)(void *lock), 2836 void (*wlock_acquire)(void *lock), 2837 void (*lock_release)(void *lock), 2838 void (*lock_destroy)(void *lock), 2839 void (*context_destroy)(void *context)) 2840{ 2841 static void *cur_context; 2842 static void (*cur_context_destroy)(void *); 2843 2844 /* Just destroy the context from the previous call, if necessary. */ 2845 if (cur_context_destroy != NULL) 2846 cur_context_destroy(cur_context); 2847 cur_context = context; 2848 cur_context_destroy = context_destroy; 2849} 2850 2851void * 2852dlopen(const char *name, int mode) 2853{ 2854 2855 return (rtld_dlopen(name, -1, mode)); 2856} 2857 2858void * 2859fdlopen(int fd, int mode) 2860{ 2861 2862 return (rtld_dlopen(NULL, fd, mode)); 2863} 2864 2865static void * 2866rtld_dlopen(const char *name, int fd, int mode) 2867{ 2868 RtldLockState lockstate; 2869 int lo_flags; 2870 2871 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2872 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2873 if (ld_tracing != NULL) { 2874 rlock_acquire(rtld_bind_lock, &lockstate); 2875 if (sigsetjmp(lockstate.env, 0) != 0) 2876 lock_upgrade(rtld_bind_lock, &lockstate); 2877 environ = (char **)*get_program_var_addr("environ", &lockstate); 2878 lock_release(rtld_bind_lock, &lockstate); 2879 } 2880 lo_flags = RTLD_LO_DLOPEN; 2881 if (mode & RTLD_NODELETE) 2882 lo_flags |= RTLD_LO_NODELETE; 2883 if (mode & RTLD_NOLOAD) 2884 lo_flags |= RTLD_LO_NOLOAD; 2885 if (ld_tracing != NULL) 2886 lo_flags |= RTLD_LO_TRACE; 2887 2888 return (dlopen_object(name, fd, obj_main, lo_flags, 2889 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2890} 2891 2892static void 2893dlopen_cleanup(Obj_Entry *obj) 2894{ 2895 2896 obj->dl_refcount--; 2897 unref_dag(obj); 2898 if (obj->refcount == 0) 2899 unload_object(obj); 2900} 2901 2902static Obj_Entry * 2903dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 2904 int mode, RtldLockState *lockstate) 2905{ 2906 Obj_Entry **old_obj_tail; 2907 Obj_Entry *obj; 2908 Objlist initlist; 2909 RtldLockState mlockstate; 2910 int result; 2911 2912 objlist_init(&initlist); 2913 2914 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 2915 wlock_acquire(rtld_bind_lock, &mlockstate); 2916 lockstate = &mlockstate; 2917 } 2918 GDB_STATE(RT_ADD,NULL); 2919 2920 old_obj_tail = obj_tail; 2921 obj = NULL; 2922 if (name == NULL && fd == -1) { 2923 obj = obj_main; 2924 obj->refcount++; 2925 } else { 2926 obj = load_object(name, fd, refobj, lo_flags); 2927 } 2928 2929 if (obj) { 2930 obj->dl_refcount++; 2931 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 2932 objlist_push_tail(&list_global, obj); 2933 if (*old_obj_tail != NULL) { /* We loaded something new. */ 2934 assert(*old_obj_tail == obj); 2935 result = load_needed_objects(obj, 2936 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 2937 init_dag(obj); 2938 ref_dag(obj); 2939 if (result != -1) 2940 result = rtld_verify_versions(&obj->dagmembers); 2941 if (result != -1 && ld_tracing) 2942 goto trace; 2943 if (result == -1 || relocate_object_dag(obj, 2944 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 2945 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 2946 lockstate) == -1) { 2947 dlopen_cleanup(obj); 2948 obj = NULL; 2949 } else if (lo_flags & RTLD_LO_EARLY) { 2950 /* 2951 * Do not call the init functions for early loaded 2952 * filtees. The image is still not initialized enough 2953 * for them to work. 2954 * 2955 * Our object is found by the global object list and 2956 * will be ordered among all init calls done right 2957 * before transferring control to main. 2958 */ 2959 } else { 2960 /* Make list of init functions to call. */ 2961 initlist_add_objects(obj, &obj->next, &initlist); 2962 } 2963 /* 2964 * Process all no_delete objects here, given them own 2965 * DAGs to prevent their dependencies from being unloaded. 2966 * This has to be done after we have loaded all of the 2967 * dependencies, so that we do not miss any. 2968 */ 2969 if (obj != NULL) 2970 process_nodelete(obj); 2971 } else { 2972 /* 2973 * Bump the reference counts for objects on this DAG. If 2974 * this is the first dlopen() call for the object that was 2975 * already loaded as a dependency, initialize the dag 2976 * starting at it. 2977 */ 2978 init_dag(obj); 2979 ref_dag(obj); 2980 2981 if ((lo_flags & RTLD_LO_TRACE) != 0) 2982 goto trace; 2983 } 2984 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 2985 obj->z_nodelete) && !obj->ref_nodel) { 2986 dbg("obj %s nodelete", obj->path); 2987 ref_dag(obj); 2988 obj->z_nodelete = obj->ref_nodel = true; 2989 } 2990 } 2991 2992 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 2993 name); 2994 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 2995 2996 if (!(lo_flags & RTLD_LO_EARLY)) { 2997 map_stacks_exec(lockstate); 2998 } 2999 3000 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3001 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3002 lockstate) == -1) { 3003 objlist_clear(&initlist); 3004 dlopen_cleanup(obj); 3005 if (lockstate == &mlockstate) 3006 lock_release(rtld_bind_lock, lockstate); 3007 return (NULL); 3008 } 3009 3010 if (!(lo_flags & RTLD_LO_EARLY)) { 3011 /* Call the init functions. */ 3012 objlist_call_init(&initlist, lockstate); 3013 } 3014 objlist_clear(&initlist); 3015 if (lockstate == &mlockstate) 3016 lock_release(rtld_bind_lock, lockstate); 3017 return obj; 3018trace: 3019 trace_loaded_objects(obj); 3020 if (lockstate == &mlockstate) 3021 lock_release(rtld_bind_lock, lockstate); 3022 exit(0); 3023} 3024 3025static void * 3026do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3027 int flags) 3028{ 3029 DoneList donelist; 3030 const Obj_Entry *obj, *defobj; 3031 const Elf_Sym *def; 3032 SymLook req; 3033 RtldLockState lockstate; 3034#ifndef __ia64__ 3035 tls_index ti; 3036#endif 3037 int res; 3038 3039 def = NULL; 3040 defobj = NULL; 3041 symlook_init(&req, name); 3042 req.ventry = ve; 3043 req.flags = flags | SYMLOOK_IN_PLT; 3044 req.lockstate = &lockstate; 3045 3046 rlock_acquire(rtld_bind_lock, &lockstate); 3047 if (sigsetjmp(lockstate.env, 0) != 0) 3048 lock_upgrade(rtld_bind_lock, &lockstate); 3049 if (handle == NULL || handle == RTLD_NEXT || 3050 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3051 3052 if ((obj = obj_from_addr(retaddr)) == NULL) { 3053 _rtld_error("Cannot determine caller's shared object"); 3054 lock_release(rtld_bind_lock, &lockstate); 3055 return NULL; 3056 } 3057 if (handle == NULL) { /* Just the caller's shared object. */ 3058 res = symlook_obj(&req, obj); 3059 if (res == 0) { 3060 def = req.sym_out; 3061 defobj = req.defobj_out; 3062 } 3063 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3064 handle == RTLD_SELF) { /* ... caller included */ 3065 if (handle == RTLD_NEXT) 3066 obj = obj->next; 3067 for (; obj != NULL; obj = obj->next) { 3068 res = symlook_obj(&req, obj); 3069 if (res == 0) { 3070 if (def == NULL || 3071 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3072 def = req.sym_out; 3073 defobj = req.defobj_out; 3074 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3075 break; 3076 } 3077 } 3078 } 3079 /* 3080 * Search the dynamic linker itself, and possibly resolve the 3081 * symbol from there. This is how the application links to 3082 * dynamic linker services such as dlopen. 3083 */ 3084 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3085 res = symlook_obj(&req, &obj_rtld); 3086 if (res == 0) { 3087 def = req.sym_out; 3088 defobj = req.defobj_out; 3089 } 3090 } 3091 } else { 3092 assert(handle == RTLD_DEFAULT); 3093 res = symlook_default(&req, obj); 3094 if (res == 0) { 3095 defobj = req.defobj_out; 3096 def = req.sym_out; 3097 } 3098 } 3099 } else { 3100 if ((obj = dlcheck(handle)) == NULL) { 3101 lock_release(rtld_bind_lock, &lockstate); 3102 return NULL; 3103 } 3104 3105 donelist_init(&donelist); 3106 if (obj->mainprog) { 3107 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3108 res = symlook_global(&req, &donelist); 3109 if (res == 0) { 3110 def = req.sym_out; 3111 defobj = req.defobj_out; 3112 } 3113 /* 3114 * Search the dynamic linker itself, and possibly resolve the 3115 * symbol from there. This is how the application links to 3116 * dynamic linker services such as dlopen. 3117 */ 3118 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3119 res = symlook_obj(&req, &obj_rtld); 3120 if (res == 0) { 3121 def = req.sym_out; 3122 defobj = req.defobj_out; 3123 } 3124 } 3125 } 3126 else { 3127 /* Search the whole DAG rooted at the given object. */ 3128 res = symlook_list(&req, &obj->dagmembers, &donelist); 3129 if (res == 0) { 3130 def = req.sym_out; 3131 defobj = req.defobj_out; 3132 } 3133 } 3134 } 3135 3136 if (def != NULL) { 3137 lock_release(rtld_bind_lock, &lockstate); 3138 3139 /* 3140 * The value required by the caller is derived from the value 3141 * of the symbol. For the ia64 architecture, we need to 3142 * construct a function descriptor which the caller can use to 3143 * call the function with the right 'gp' value. For other 3144 * architectures and for non-functions, the value is simply 3145 * the relocated value of the symbol. 3146 */ 3147 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3148 return (make_function_pointer(def, defobj)); 3149 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3150 return (rtld_resolve_ifunc(defobj, def)); 3151 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3152#ifdef __ia64__ 3153 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3154#else 3155 ti.ti_module = defobj->tlsindex; 3156 ti.ti_offset = def->st_value; 3157 return (__tls_get_addr(&ti)); 3158#endif 3159 } else 3160 return (defobj->relocbase + def->st_value); 3161 } 3162 3163 _rtld_error("Undefined symbol \"%s\"", name); 3164 lock_release(rtld_bind_lock, &lockstate); 3165 return NULL; 3166} 3167 3168void * 3169dlsym(void *handle, const char *name) 3170{ 3171 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3172 SYMLOOK_DLSYM); 3173} 3174 3175dlfunc_t 3176dlfunc(void *handle, const char *name) 3177{ 3178 union { 3179 void *d; 3180 dlfunc_t f; 3181 } rv; 3182 3183 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3184 SYMLOOK_DLSYM); 3185 return (rv.f); 3186} 3187 3188void * 3189dlvsym(void *handle, const char *name, const char *version) 3190{ 3191 Ver_Entry ventry; 3192 3193 ventry.name = version; 3194 ventry.file = NULL; 3195 ventry.hash = elf_hash(version); 3196 ventry.flags= 0; 3197 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3198 SYMLOOK_DLSYM); 3199} 3200 3201int 3202_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3203{ 3204 const Obj_Entry *obj; 3205 RtldLockState lockstate; 3206 3207 rlock_acquire(rtld_bind_lock, &lockstate); 3208 obj = obj_from_addr(addr); 3209 if (obj == NULL) { 3210 _rtld_error("No shared object contains address"); 3211 lock_release(rtld_bind_lock, &lockstate); 3212 return (0); 3213 } 3214 rtld_fill_dl_phdr_info(obj, phdr_info); 3215 lock_release(rtld_bind_lock, &lockstate); 3216 return (1); 3217} 3218 3219int 3220dladdr(const void *addr, Dl_info *info) 3221{ 3222 const Obj_Entry *obj; 3223 const Elf_Sym *def; 3224 void *symbol_addr; 3225 unsigned long symoffset; 3226 RtldLockState lockstate; 3227 3228 rlock_acquire(rtld_bind_lock, &lockstate); 3229 obj = obj_from_addr(addr); 3230 if (obj == NULL) { 3231 _rtld_error("No shared object contains address"); 3232 lock_release(rtld_bind_lock, &lockstate); 3233 return 0; 3234 } 3235 info->dli_fname = obj->path; 3236 info->dli_fbase = obj->mapbase; 3237 info->dli_saddr = (void *)0; 3238 info->dli_sname = NULL; 3239 3240 /* 3241 * Walk the symbol list looking for the symbol whose address is 3242 * closest to the address sent in. 3243 */ 3244 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3245 def = obj->symtab + symoffset; 3246 3247 /* 3248 * For skip the symbol if st_shndx is either SHN_UNDEF or 3249 * SHN_COMMON. 3250 */ 3251 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3252 continue; 3253 3254 /* 3255 * If the symbol is greater than the specified address, or if it 3256 * is further away from addr than the current nearest symbol, 3257 * then reject it. 3258 */ 3259 symbol_addr = obj->relocbase + def->st_value; 3260 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3261 continue; 3262 3263 /* Update our idea of the nearest symbol. */ 3264 info->dli_sname = obj->strtab + def->st_name; 3265 info->dli_saddr = symbol_addr; 3266 3267 /* Exact match? */ 3268 if (info->dli_saddr == addr) 3269 break; 3270 } 3271 lock_release(rtld_bind_lock, &lockstate); 3272 return 1; 3273} 3274 3275int 3276dlinfo(void *handle, int request, void *p) 3277{ 3278 const Obj_Entry *obj; 3279 RtldLockState lockstate; 3280 int error; 3281 3282 rlock_acquire(rtld_bind_lock, &lockstate); 3283 3284 if (handle == NULL || handle == RTLD_SELF) { 3285 void *retaddr; 3286 3287 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3288 if ((obj = obj_from_addr(retaddr)) == NULL) 3289 _rtld_error("Cannot determine caller's shared object"); 3290 } else 3291 obj = dlcheck(handle); 3292 3293 if (obj == NULL) { 3294 lock_release(rtld_bind_lock, &lockstate); 3295 return (-1); 3296 } 3297 3298 error = 0; 3299 switch (request) { 3300 case RTLD_DI_LINKMAP: 3301 *((struct link_map const **)p) = &obj->linkmap; 3302 break; 3303 case RTLD_DI_ORIGIN: 3304 error = rtld_dirname(obj->path, p); 3305 break; 3306 3307 case RTLD_DI_SERINFOSIZE: 3308 case RTLD_DI_SERINFO: 3309 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3310 break; 3311 3312 default: 3313 _rtld_error("Invalid request %d passed to dlinfo()", request); 3314 error = -1; 3315 } 3316 3317 lock_release(rtld_bind_lock, &lockstate); 3318 3319 return (error); 3320} 3321 3322static void 3323rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3324{ 3325 3326 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3327 phdr_info->dlpi_name = obj->path; 3328 phdr_info->dlpi_phdr = obj->phdr; 3329 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3330 phdr_info->dlpi_tls_modid = obj->tlsindex; 3331 phdr_info->dlpi_tls_data = obj->tlsinit; 3332 phdr_info->dlpi_adds = obj_loads; 3333 phdr_info->dlpi_subs = obj_loads - obj_count; 3334} 3335 3336int 3337dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3338{ 3339 struct dl_phdr_info phdr_info; 3340 const Obj_Entry *obj; 3341 RtldLockState bind_lockstate, phdr_lockstate; 3342 int error; 3343 3344 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3345 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3346 3347 error = 0; 3348 3349 for (obj = obj_list; obj != NULL; obj = obj->next) { 3350 rtld_fill_dl_phdr_info(obj, &phdr_info); 3351 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3352 break; 3353 3354 } 3355 lock_release(rtld_bind_lock, &bind_lockstate); 3356 lock_release(rtld_phdr_lock, &phdr_lockstate); 3357 3358 return (error); 3359} 3360 3361static void * 3362fill_search_info(const char *dir, size_t dirlen, void *param) 3363{ 3364 struct fill_search_info_args *arg; 3365 3366 arg = param; 3367 3368 if (arg->request == RTLD_DI_SERINFOSIZE) { 3369 arg->serinfo->dls_cnt ++; 3370 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3371 } else { 3372 struct dl_serpath *s_entry; 3373 3374 s_entry = arg->serpath; 3375 s_entry->dls_name = arg->strspace; 3376 s_entry->dls_flags = arg->flags; 3377 3378 strncpy(arg->strspace, dir, dirlen); 3379 arg->strspace[dirlen] = '\0'; 3380 3381 arg->strspace += dirlen + 1; 3382 arg->serpath++; 3383 } 3384 3385 return (NULL); 3386} 3387 3388static int 3389do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3390{ 3391 struct dl_serinfo _info; 3392 struct fill_search_info_args args; 3393 3394 args.request = RTLD_DI_SERINFOSIZE; 3395 args.serinfo = &_info; 3396 3397 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3398 _info.dls_cnt = 0; 3399 3400 path_enumerate(obj->rpath, fill_search_info, &args); 3401 path_enumerate(ld_library_path, fill_search_info, &args); 3402 path_enumerate(obj->runpath, fill_search_info, &args); 3403 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3404 if (!obj->z_nodeflib) 3405 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3406 3407 3408 if (request == RTLD_DI_SERINFOSIZE) { 3409 info->dls_size = _info.dls_size; 3410 info->dls_cnt = _info.dls_cnt; 3411 return (0); 3412 } 3413 3414 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3415 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3416 return (-1); 3417 } 3418 3419 args.request = RTLD_DI_SERINFO; 3420 args.serinfo = info; 3421 args.serpath = &info->dls_serpath[0]; 3422 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3423 3424 args.flags = LA_SER_RUNPATH; 3425 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3426 return (-1); 3427 3428 args.flags = LA_SER_LIBPATH; 3429 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3430 return (-1); 3431 3432 args.flags = LA_SER_RUNPATH; 3433 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3434 return (-1); 3435 3436 args.flags = LA_SER_CONFIG; 3437 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3438 != NULL) 3439 return (-1); 3440 3441 args.flags = LA_SER_DEFAULT; 3442 if (!obj->z_nodeflib && 3443 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3444 return (-1); 3445 return (0); 3446} 3447 3448static int 3449rtld_dirname(const char *path, char *bname) 3450{ 3451 const char *endp; 3452 3453 /* Empty or NULL string gets treated as "." */ 3454 if (path == NULL || *path == '\0') { 3455 bname[0] = '.'; 3456 bname[1] = '\0'; 3457 return (0); 3458 } 3459 3460 /* Strip trailing slashes */ 3461 endp = path + strlen(path) - 1; 3462 while (endp > path && *endp == '/') 3463 endp--; 3464 3465 /* Find the start of the dir */ 3466 while (endp > path && *endp != '/') 3467 endp--; 3468 3469 /* Either the dir is "/" or there are no slashes */ 3470 if (endp == path) { 3471 bname[0] = *endp == '/' ? '/' : '.'; 3472 bname[1] = '\0'; 3473 return (0); 3474 } else { 3475 do { 3476 endp--; 3477 } while (endp > path && *endp == '/'); 3478 } 3479 3480 if (endp - path + 2 > PATH_MAX) 3481 { 3482 _rtld_error("Filename is too long: %s", path); 3483 return(-1); 3484 } 3485 3486 strncpy(bname, path, endp - path + 1); 3487 bname[endp - path + 1] = '\0'; 3488 return (0); 3489} 3490 3491static int 3492rtld_dirname_abs(const char *path, char *base) 3493{ 3494 char *last; 3495 3496 if (realpath(path, base) == NULL) 3497 return (-1); 3498 dbg("%s -> %s", path, base); 3499 last = strrchr(base, '/'); 3500 if (last == NULL) 3501 return (-1); 3502 if (last != base) 3503 *last = '\0'; 3504 return (0); 3505} 3506 3507static void 3508linkmap_add(Obj_Entry *obj) 3509{ 3510 struct link_map *l = &obj->linkmap; 3511 struct link_map *prev; 3512 3513 obj->linkmap.l_name = obj->path; 3514 obj->linkmap.l_addr = obj->mapbase; 3515 obj->linkmap.l_ld = obj->dynamic; 3516#ifdef __mips__ 3517 /* GDB needs load offset on MIPS to use the symbols */ 3518 obj->linkmap.l_offs = obj->relocbase; 3519#endif 3520 3521 if (r_debug.r_map == NULL) { 3522 r_debug.r_map = l; 3523 return; 3524 } 3525 3526 /* 3527 * Scan to the end of the list, but not past the entry for the 3528 * dynamic linker, which we want to keep at the very end. 3529 */ 3530 for (prev = r_debug.r_map; 3531 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3532 prev = prev->l_next) 3533 ; 3534 3535 /* Link in the new entry. */ 3536 l->l_prev = prev; 3537 l->l_next = prev->l_next; 3538 if (l->l_next != NULL) 3539 l->l_next->l_prev = l; 3540 prev->l_next = l; 3541} 3542 3543static void 3544linkmap_delete(Obj_Entry *obj) 3545{ 3546 struct link_map *l = &obj->linkmap; 3547 3548 if (l->l_prev == NULL) { 3549 if ((r_debug.r_map = l->l_next) != NULL) 3550 l->l_next->l_prev = NULL; 3551 return; 3552 } 3553 3554 if ((l->l_prev->l_next = l->l_next) != NULL) 3555 l->l_next->l_prev = l->l_prev; 3556} 3557 3558/* 3559 * Function for the debugger to set a breakpoint on to gain control. 3560 * 3561 * The two parameters allow the debugger to easily find and determine 3562 * what the runtime loader is doing and to whom it is doing it. 3563 * 3564 * When the loadhook trap is hit (r_debug_state, set at program 3565 * initialization), the arguments can be found on the stack: 3566 * 3567 * +8 struct link_map *m 3568 * +4 struct r_debug *rd 3569 * +0 RetAddr 3570 */ 3571void 3572r_debug_state(struct r_debug* rd, struct link_map *m) 3573{ 3574 /* 3575 * The following is a hack to force the compiler to emit calls to 3576 * this function, even when optimizing. If the function is empty, 3577 * the compiler is not obliged to emit any code for calls to it, 3578 * even when marked __noinline. However, gdb depends on those 3579 * calls being made. 3580 */ 3581 __compiler_membar(); 3582} 3583 3584/* 3585 * A function called after init routines have completed. This can be used to 3586 * break before a program's entry routine is called, and can be used when 3587 * main is not available in the symbol table. 3588 */ 3589void 3590_r_debug_postinit(struct link_map *m) 3591{ 3592 3593 /* See r_debug_state(). */ 3594 __compiler_membar(); 3595} 3596 3597/* 3598 * Get address of the pointer variable in the main program. 3599 * Prefer non-weak symbol over the weak one. 3600 */ 3601static const void ** 3602get_program_var_addr(const char *name, RtldLockState *lockstate) 3603{ 3604 SymLook req; 3605 DoneList donelist; 3606 3607 symlook_init(&req, name); 3608 req.lockstate = lockstate; 3609 donelist_init(&donelist); 3610 if (symlook_global(&req, &donelist) != 0) 3611 return (NULL); 3612 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3613 return ((const void **)make_function_pointer(req.sym_out, 3614 req.defobj_out)); 3615 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3616 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3617 else 3618 return ((const void **)(req.defobj_out->relocbase + 3619 req.sym_out->st_value)); 3620} 3621 3622/* 3623 * Set a pointer variable in the main program to the given value. This 3624 * is used to set key variables such as "environ" before any of the 3625 * init functions are called. 3626 */ 3627static void 3628set_program_var(const char *name, const void *value) 3629{ 3630 const void **addr; 3631 3632 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3633 dbg("\"%s\": *%p <-- %p", name, addr, value); 3634 *addr = value; 3635 } 3636} 3637 3638/* 3639 * Search the global objects, including dependencies and main object, 3640 * for the given symbol. 3641 */ 3642static int 3643symlook_global(SymLook *req, DoneList *donelist) 3644{ 3645 SymLook req1; 3646 const Objlist_Entry *elm; 3647 int res; 3648 3649 symlook_init_from_req(&req1, req); 3650 3651 /* Search all objects loaded at program start up. */ 3652 if (req->defobj_out == NULL || 3653 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3654 res = symlook_list(&req1, &list_main, donelist); 3655 if (res == 0 && (req->defobj_out == NULL || 3656 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3657 req->sym_out = req1.sym_out; 3658 req->defobj_out = req1.defobj_out; 3659 assert(req->defobj_out != NULL); 3660 } 3661 } 3662 3663 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3664 STAILQ_FOREACH(elm, &list_global, link) { 3665 if (req->defobj_out != NULL && 3666 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3667 break; 3668 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3669 if (res == 0 && (req->defobj_out == NULL || 3670 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3671 req->sym_out = req1.sym_out; 3672 req->defobj_out = req1.defobj_out; 3673 assert(req->defobj_out != NULL); 3674 } 3675 } 3676 3677 return (req->sym_out != NULL ? 0 : ESRCH); 3678} 3679 3680/* 3681 * Given a symbol name in a referencing object, find the corresponding 3682 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3683 * no definition was found. Returns a pointer to the Obj_Entry of the 3684 * defining object via the reference parameter DEFOBJ_OUT. 3685 */ 3686static int 3687symlook_default(SymLook *req, const Obj_Entry *refobj) 3688{ 3689 DoneList donelist; 3690 const Objlist_Entry *elm; 3691 SymLook req1; 3692 int res; 3693 3694 donelist_init(&donelist); 3695 symlook_init_from_req(&req1, req); 3696 3697 /* Look first in the referencing object if linked symbolically. */ 3698 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3699 res = symlook_obj(&req1, refobj); 3700 if (res == 0) { 3701 req->sym_out = req1.sym_out; 3702 req->defobj_out = req1.defobj_out; 3703 assert(req->defobj_out != NULL); 3704 } 3705 } 3706 3707 symlook_global(req, &donelist); 3708 3709 /* Search all dlopened DAGs containing the referencing object. */ 3710 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3711 if (req->sym_out != NULL && 3712 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3713 break; 3714 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3715 if (res == 0 && (req->sym_out == NULL || 3716 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3717 req->sym_out = req1.sym_out; 3718 req->defobj_out = req1.defobj_out; 3719 assert(req->defobj_out != NULL); 3720 } 3721 } 3722 3723 /* 3724 * Search the dynamic linker itself, and possibly resolve the 3725 * symbol from there. This is how the application links to 3726 * dynamic linker services such as dlopen. 3727 */ 3728 if (req->sym_out == NULL || 3729 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3730 res = symlook_obj(&req1, &obj_rtld); 3731 if (res == 0) { 3732 req->sym_out = req1.sym_out; 3733 req->defobj_out = req1.defobj_out; 3734 assert(req->defobj_out != NULL); 3735 } 3736 } 3737 3738 return (req->sym_out != NULL ? 0 : ESRCH); 3739} 3740 3741static int 3742symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3743{ 3744 const Elf_Sym *def; 3745 const Obj_Entry *defobj; 3746 const Objlist_Entry *elm; 3747 SymLook req1; 3748 int res; 3749 3750 def = NULL; 3751 defobj = NULL; 3752 STAILQ_FOREACH(elm, objlist, link) { 3753 if (donelist_check(dlp, elm->obj)) 3754 continue; 3755 symlook_init_from_req(&req1, req); 3756 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3757 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3758 def = req1.sym_out; 3759 defobj = req1.defobj_out; 3760 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3761 break; 3762 } 3763 } 3764 } 3765 if (def != NULL) { 3766 req->sym_out = def; 3767 req->defobj_out = defobj; 3768 return (0); 3769 } 3770 return (ESRCH); 3771} 3772 3773/* 3774 * Search the chain of DAGS cointed to by the given Needed_Entry 3775 * for a symbol of the given name. Each DAG is scanned completely 3776 * before advancing to the next one. Returns a pointer to the symbol, 3777 * or NULL if no definition was found. 3778 */ 3779static int 3780symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3781{ 3782 const Elf_Sym *def; 3783 const Needed_Entry *n; 3784 const Obj_Entry *defobj; 3785 SymLook req1; 3786 int res; 3787 3788 def = NULL; 3789 defobj = NULL; 3790 symlook_init_from_req(&req1, req); 3791 for (n = needed; n != NULL; n = n->next) { 3792 if (n->obj == NULL || 3793 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3794 continue; 3795 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3796 def = req1.sym_out; 3797 defobj = req1.defobj_out; 3798 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3799 break; 3800 } 3801 } 3802 if (def != NULL) { 3803 req->sym_out = def; 3804 req->defobj_out = defobj; 3805 return (0); 3806 } 3807 return (ESRCH); 3808} 3809 3810/* 3811 * Search the symbol table of a single shared object for a symbol of 3812 * the given name and version, if requested. Returns a pointer to the 3813 * symbol, or NULL if no definition was found. If the object is 3814 * filter, return filtered symbol from filtee. 3815 * 3816 * The symbol's hash value is passed in for efficiency reasons; that 3817 * eliminates many recomputations of the hash value. 3818 */ 3819int 3820symlook_obj(SymLook *req, const Obj_Entry *obj) 3821{ 3822 DoneList donelist; 3823 SymLook req1; 3824 int flags, res, mres; 3825 3826 /* 3827 * If there is at least one valid hash at this point, we prefer to 3828 * use the faster GNU version if available. 3829 */ 3830 if (obj->valid_hash_gnu) 3831 mres = symlook_obj1_gnu(req, obj); 3832 else if (obj->valid_hash_sysv) 3833 mres = symlook_obj1_sysv(req, obj); 3834 else 3835 return (EINVAL); 3836 3837 if (mres == 0) { 3838 if (obj->needed_filtees != NULL) { 3839 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3840 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3841 donelist_init(&donelist); 3842 symlook_init_from_req(&req1, req); 3843 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3844 if (res == 0) { 3845 req->sym_out = req1.sym_out; 3846 req->defobj_out = req1.defobj_out; 3847 } 3848 return (res); 3849 } 3850 if (obj->needed_aux_filtees != NULL) { 3851 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3852 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3853 donelist_init(&donelist); 3854 symlook_init_from_req(&req1, req); 3855 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3856 if (res == 0) { 3857 req->sym_out = req1.sym_out; 3858 req->defobj_out = req1.defobj_out; 3859 return (res); 3860 } 3861 } 3862 } 3863 return (mres); 3864} 3865 3866/* Symbol match routine common to both hash functions */ 3867static bool 3868matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3869 const unsigned long symnum) 3870{ 3871 Elf_Versym verndx; 3872 const Elf_Sym *symp; 3873 const char *strp; 3874 3875 symp = obj->symtab + symnum; 3876 strp = obj->strtab + symp->st_name; 3877 3878 switch (ELF_ST_TYPE(symp->st_info)) { 3879 case STT_FUNC: 3880 case STT_NOTYPE: 3881 case STT_OBJECT: 3882 case STT_COMMON: 3883 case STT_GNU_IFUNC: 3884 if (symp->st_value == 0) 3885 return (false); 3886 /* fallthrough */ 3887 case STT_TLS: 3888 if (symp->st_shndx != SHN_UNDEF) 3889 break; 3890#ifndef __mips__ 3891 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3892 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3893 break; 3894 /* fallthrough */ 3895#endif 3896 default: 3897 return (false); 3898 } 3899 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 3900 return (false); 3901 3902 if (req->ventry == NULL) { 3903 if (obj->versyms != NULL) { 3904 verndx = VER_NDX(obj->versyms[symnum]); 3905 if (verndx > obj->vernum) { 3906 _rtld_error( 3907 "%s: symbol %s references wrong version %d", 3908 obj->path, obj->strtab + symnum, verndx); 3909 return (false); 3910 } 3911 /* 3912 * If we are not called from dlsym (i.e. this 3913 * is a normal relocation from unversioned 3914 * binary), accept the symbol immediately if 3915 * it happens to have first version after this 3916 * shared object became versioned. Otherwise, 3917 * if symbol is versioned and not hidden, 3918 * remember it. If it is the only symbol with 3919 * this name exported by the shared object, it 3920 * will be returned as a match by the calling 3921 * function. If symbol is global (verndx < 2) 3922 * accept it unconditionally. 3923 */ 3924 if ((req->flags & SYMLOOK_DLSYM) == 0 && 3925 verndx == VER_NDX_GIVEN) { 3926 result->sym_out = symp; 3927 return (true); 3928 } 3929 else if (verndx >= VER_NDX_GIVEN) { 3930 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 3931 == 0) { 3932 if (result->vsymp == NULL) 3933 result->vsymp = symp; 3934 result->vcount++; 3935 } 3936 return (false); 3937 } 3938 } 3939 result->sym_out = symp; 3940 return (true); 3941 } 3942 if (obj->versyms == NULL) { 3943 if (object_match_name(obj, req->ventry->name)) { 3944 _rtld_error("%s: object %s should provide version %s " 3945 "for symbol %s", obj_rtld.path, obj->path, 3946 req->ventry->name, obj->strtab + symnum); 3947 return (false); 3948 } 3949 } else { 3950 verndx = VER_NDX(obj->versyms[symnum]); 3951 if (verndx > obj->vernum) { 3952 _rtld_error("%s: symbol %s references wrong version %d", 3953 obj->path, obj->strtab + symnum, verndx); 3954 return (false); 3955 } 3956 if (obj->vertab[verndx].hash != req->ventry->hash || 3957 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 3958 /* 3959 * Version does not match. Look if this is a 3960 * global symbol and if it is not hidden. If 3961 * global symbol (verndx < 2) is available, 3962 * use it. Do not return symbol if we are 3963 * called by dlvsym, because dlvsym looks for 3964 * a specific version and default one is not 3965 * what dlvsym wants. 3966 */ 3967 if ((req->flags & SYMLOOK_DLSYM) || 3968 (verndx >= VER_NDX_GIVEN) || 3969 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 3970 return (false); 3971 } 3972 } 3973 result->sym_out = symp; 3974 return (true); 3975} 3976 3977/* 3978 * Search for symbol using SysV hash function. 3979 * obj->buckets is known not to be NULL at this point; the test for this was 3980 * performed with the obj->valid_hash_sysv assignment. 3981 */ 3982static int 3983symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 3984{ 3985 unsigned long symnum; 3986 Sym_Match_Result matchres; 3987 3988 matchres.sym_out = NULL; 3989 matchres.vsymp = NULL; 3990 matchres.vcount = 0; 3991 3992 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 3993 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 3994 if (symnum >= obj->nchains) 3995 return (ESRCH); /* Bad object */ 3996 3997 if (matched_symbol(req, obj, &matchres, symnum)) { 3998 req->sym_out = matchres.sym_out; 3999 req->defobj_out = obj; 4000 return (0); 4001 } 4002 } 4003 if (matchres.vcount == 1) { 4004 req->sym_out = matchres.vsymp; 4005 req->defobj_out = obj; 4006 return (0); 4007 } 4008 return (ESRCH); 4009} 4010 4011/* Search for symbol using GNU hash function */ 4012static int 4013symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4014{ 4015 Elf_Addr bloom_word; 4016 const Elf32_Word *hashval; 4017 Elf32_Word bucket; 4018 Sym_Match_Result matchres; 4019 unsigned int h1, h2; 4020 unsigned long symnum; 4021 4022 matchres.sym_out = NULL; 4023 matchres.vsymp = NULL; 4024 matchres.vcount = 0; 4025 4026 /* Pick right bitmask word from Bloom filter array */ 4027 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4028 obj->maskwords_bm_gnu]; 4029 4030 /* Calculate modulus word size of gnu hash and its derivative */ 4031 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4032 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4033 4034 /* Filter out the "definitely not in set" queries */ 4035 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4036 return (ESRCH); 4037 4038 /* Locate hash chain and corresponding value element*/ 4039 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4040 if (bucket == 0) 4041 return (ESRCH); 4042 hashval = &obj->chain_zero_gnu[bucket]; 4043 do { 4044 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4045 symnum = hashval - obj->chain_zero_gnu; 4046 if (matched_symbol(req, obj, &matchres, symnum)) { 4047 req->sym_out = matchres.sym_out; 4048 req->defobj_out = obj; 4049 return (0); 4050 } 4051 } 4052 } while ((*hashval++ & 1) == 0); 4053 if (matchres.vcount == 1) { 4054 req->sym_out = matchres.vsymp; 4055 req->defobj_out = obj; 4056 return (0); 4057 } 4058 return (ESRCH); 4059} 4060 4061static void 4062trace_loaded_objects(Obj_Entry *obj) 4063{ 4064 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4065 int c; 4066 4067 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4068 main_local = ""; 4069 4070 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4071 fmt1 = "\t%o => %p (%x)\n"; 4072 4073 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4074 fmt2 = "\t%o (%x)\n"; 4075 4076 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4077 4078 for (; obj; obj = obj->next) { 4079 Needed_Entry *needed; 4080 char *name, *path; 4081 bool is_lib; 4082 4083 if (list_containers && obj->needed != NULL) 4084 rtld_printf("%s:\n", obj->path); 4085 for (needed = obj->needed; needed; needed = needed->next) { 4086 if (needed->obj != NULL) { 4087 if (needed->obj->traced && !list_containers) 4088 continue; 4089 needed->obj->traced = true; 4090 path = needed->obj->path; 4091 } else 4092 path = "not found"; 4093 4094 name = (char *)obj->strtab + needed->name; 4095 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4096 4097 fmt = is_lib ? fmt1 : fmt2; 4098 while ((c = *fmt++) != '\0') { 4099 switch (c) { 4100 default: 4101 rtld_putchar(c); 4102 continue; 4103 case '\\': 4104 switch (c = *fmt) { 4105 case '\0': 4106 continue; 4107 case 'n': 4108 rtld_putchar('\n'); 4109 break; 4110 case 't': 4111 rtld_putchar('\t'); 4112 break; 4113 } 4114 break; 4115 case '%': 4116 switch (c = *fmt) { 4117 case '\0': 4118 continue; 4119 case '%': 4120 default: 4121 rtld_putchar(c); 4122 break; 4123 case 'A': 4124 rtld_putstr(main_local); 4125 break; 4126 case 'a': 4127 rtld_putstr(obj_main->path); 4128 break; 4129 case 'o': 4130 rtld_putstr(name); 4131 break; 4132#if 0 4133 case 'm': 4134 rtld_printf("%d", sodp->sod_major); 4135 break; 4136 case 'n': 4137 rtld_printf("%d", sodp->sod_minor); 4138 break; 4139#endif 4140 case 'p': 4141 rtld_putstr(path); 4142 break; 4143 case 'x': 4144 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4145 0); 4146 break; 4147 } 4148 break; 4149 } 4150 ++fmt; 4151 } 4152 } 4153 } 4154} 4155 4156/* 4157 * Unload a dlopened object and its dependencies from memory and from 4158 * our data structures. It is assumed that the DAG rooted in the 4159 * object has already been unreferenced, and that the object has a 4160 * reference count of 0. 4161 */ 4162static void 4163unload_object(Obj_Entry *root) 4164{ 4165 Obj_Entry *obj; 4166 Obj_Entry **linkp; 4167 4168 assert(root->refcount == 0); 4169 4170 /* 4171 * Pass over the DAG removing unreferenced objects from 4172 * appropriate lists. 4173 */ 4174 unlink_object(root); 4175 4176 /* Unmap all objects that are no longer referenced. */ 4177 linkp = &obj_list->next; 4178 while ((obj = *linkp) != NULL) { 4179 if (obj->refcount == 0) { 4180 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4181 obj->path); 4182 dbg("unloading \"%s\"", obj->path); 4183 unload_filtees(root); 4184 munmap(obj->mapbase, obj->mapsize); 4185 linkmap_delete(obj); 4186 *linkp = obj->next; 4187 obj_count--; 4188 obj_free(obj); 4189 } else 4190 linkp = &obj->next; 4191 } 4192 obj_tail = linkp; 4193} 4194 4195static void 4196unlink_object(Obj_Entry *root) 4197{ 4198 Objlist_Entry *elm; 4199 4200 if (root->refcount == 0) { 4201 /* Remove the object from the RTLD_GLOBAL list. */ 4202 objlist_remove(&list_global, root); 4203 4204 /* Remove the object from all objects' DAG lists. */ 4205 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4206 objlist_remove(&elm->obj->dldags, root); 4207 if (elm->obj != root) 4208 unlink_object(elm->obj); 4209 } 4210 } 4211} 4212 4213static void 4214ref_dag(Obj_Entry *root) 4215{ 4216 Objlist_Entry *elm; 4217 4218 assert(root->dag_inited); 4219 STAILQ_FOREACH(elm, &root->dagmembers, link) 4220 elm->obj->refcount++; 4221} 4222 4223static void 4224unref_dag(Obj_Entry *root) 4225{ 4226 Objlist_Entry *elm; 4227 4228 assert(root->dag_inited); 4229 STAILQ_FOREACH(elm, &root->dagmembers, link) 4230 elm->obj->refcount--; 4231} 4232 4233/* 4234 * Common code for MD __tls_get_addr(). 4235 */ 4236static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4237static void * 4238tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4239{ 4240 Elf_Addr *newdtv, *dtv; 4241 RtldLockState lockstate; 4242 int to_copy; 4243 4244 dtv = *dtvp; 4245 /* Check dtv generation in case new modules have arrived */ 4246 if (dtv[0] != tls_dtv_generation) { 4247 wlock_acquire(rtld_bind_lock, &lockstate); 4248 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4249 to_copy = dtv[1]; 4250 if (to_copy > tls_max_index) 4251 to_copy = tls_max_index; 4252 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4253 newdtv[0] = tls_dtv_generation; 4254 newdtv[1] = tls_max_index; 4255 free(dtv); 4256 lock_release(rtld_bind_lock, &lockstate); 4257 dtv = *dtvp = newdtv; 4258 } 4259 4260 /* Dynamically allocate module TLS if necessary */ 4261 if (dtv[index + 1] == 0) { 4262 /* Signal safe, wlock will block out signals. */ 4263 wlock_acquire(rtld_bind_lock, &lockstate); 4264 if (!dtv[index + 1]) 4265 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4266 lock_release(rtld_bind_lock, &lockstate); 4267 } 4268 return ((void *)(dtv[index + 1] + offset)); 4269} 4270 4271void * 4272tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4273{ 4274 Elf_Addr *dtv; 4275 4276 dtv = *dtvp; 4277 /* Check dtv generation in case new modules have arrived */ 4278 if (__predict_true(dtv[0] == tls_dtv_generation && 4279 dtv[index + 1] != 0)) 4280 return ((void *)(dtv[index + 1] + offset)); 4281 return (tls_get_addr_slow(dtvp, index, offset)); 4282} 4283 4284#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4285 4286/* 4287 * Allocate Static TLS using the Variant I method. 4288 */ 4289void * 4290allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4291{ 4292 Obj_Entry *obj; 4293 char *tcb; 4294 Elf_Addr **tls; 4295 Elf_Addr *dtv; 4296 Elf_Addr addr; 4297 int i; 4298 4299 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4300 return (oldtcb); 4301 4302 assert(tcbsize >= TLS_TCB_SIZE); 4303 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4304 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4305 4306 if (oldtcb != NULL) { 4307 memcpy(tls, oldtcb, tls_static_space); 4308 free(oldtcb); 4309 4310 /* Adjust the DTV. */ 4311 dtv = tls[0]; 4312 for (i = 0; i < dtv[1]; i++) { 4313 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4314 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4315 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4316 } 4317 } 4318 } else { 4319 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4320 tls[0] = dtv; 4321 dtv[0] = tls_dtv_generation; 4322 dtv[1] = tls_max_index; 4323 4324 for (obj = objs; obj; obj = obj->next) { 4325 if (obj->tlsoffset > 0) { 4326 addr = (Elf_Addr)tls + obj->tlsoffset; 4327 if (obj->tlsinitsize > 0) 4328 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4329 if (obj->tlssize > obj->tlsinitsize) 4330 memset((void*) (addr + obj->tlsinitsize), 0, 4331 obj->tlssize - obj->tlsinitsize); 4332 dtv[obj->tlsindex + 1] = addr; 4333 } 4334 } 4335 } 4336 4337 return (tcb); 4338} 4339 4340void 4341free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4342{ 4343 Elf_Addr *dtv; 4344 Elf_Addr tlsstart, tlsend; 4345 int dtvsize, i; 4346 4347 assert(tcbsize >= TLS_TCB_SIZE); 4348 4349 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4350 tlsend = tlsstart + tls_static_space; 4351 4352 dtv = *(Elf_Addr **)tlsstart; 4353 dtvsize = dtv[1]; 4354 for (i = 0; i < dtvsize; i++) { 4355 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4356 free((void*)dtv[i+2]); 4357 } 4358 } 4359 free(dtv); 4360 free(tcb); 4361} 4362 4363#endif 4364 4365#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4366 4367/* 4368 * Allocate Static TLS using the Variant II method. 4369 */ 4370void * 4371allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4372{ 4373 Obj_Entry *obj; 4374 size_t size, ralign; 4375 char *tls; 4376 Elf_Addr *dtv, *olddtv; 4377 Elf_Addr segbase, oldsegbase, addr; 4378 int i; 4379 4380 ralign = tcbalign; 4381 if (tls_static_max_align > ralign) 4382 ralign = tls_static_max_align; 4383 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4384 4385 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4386 tls = malloc_aligned(size, ralign); 4387 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4388 4389 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4390 ((Elf_Addr*)segbase)[0] = segbase; 4391 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4392 4393 dtv[0] = tls_dtv_generation; 4394 dtv[1] = tls_max_index; 4395 4396 if (oldtls) { 4397 /* 4398 * Copy the static TLS block over whole. 4399 */ 4400 oldsegbase = (Elf_Addr) oldtls; 4401 memcpy((void *)(segbase - tls_static_space), 4402 (const void *)(oldsegbase - tls_static_space), 4403 tls_static_space); 4404 4405 /* 4406 * If any dynamic TLS blocks have been created tls_get_addr(), 4407 * move them over. 4408 */ 4409 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4410 for (i = 0; i < olddtv[1]; i++) { 4411 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4412 dtv[i+2] = olddtv[i+2]; 4413 olddtv[i+2] = 0; 4414 } 4415 } 4416 4417 /* 4418 * We assume that this block was the one we created with 4419 * allocate_initial_tls(). 4420 */ 4421 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4422 } else { 4423 for (obj = objs; obj; obj = obj->next) { 4424 if (obj->tlsoffset) { 4425 addr = segbase - obj->tlsoffset; 4426 memset((void*) (addr + obj->tlsinitsize), 4427 0, obj->tlssize - obj->tlsinitsize); 4428 if (obj->tlsinit) 4429 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4430 dtv[obj->tlsindex + 1] = addr; 4431 } 4432 } 4433 } 4434 4435 return (void*) segbase; 4436} 4437 4438void 4439free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4440{ 4441 Elf_Addr* dtv; 4442 size_t size, ralign; 4443 int dtvsize, i; 4444 Elf_Addr tlsstart, tlsend; 4445 4446 /* 4447 * Figure out the size of the initial TLS block so that we can 4448 * find stuff which ___tls_get_addr() allocated dynamically. 4449 */ 4450 ralign = tcbalign; 4451 if (tls_static_max_align > ralign) 4452 ralign = tls_static_max_align; 4453 size = round(tls_static_space, ralign); 4454 4455 dtv = ((Elf_Addr**)tls)[1]; 4456 dtvsize = dtv[1]; 4457 tlsend = (Elf_Addr) tls; 4458 tlsstart = tlsend - size; 4459 for (i = 0; i < dtvsize; i++) { 4460 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4461 free_aligned((void *)dtv[i + 2]); 4462 } 4463 } 4464 4465 free_aligned((void *)tlsstart); 4466 free((void*) dtv); 4467} 4468 4469#endif 4470 4471/* 4472 * Allocate TLS block for module with given index. 4473 */ 4474void * 4475allocate_module_tls(int index) 4476{ 4477 Obj_Entry* obj; 4478 char* p; 4479 4480 for (obj = obj_list; obj; obj = obj->next) { 4481 if (obj->tlsindex == index) 4482 break; 4483 } 4484 if (!obj) { 4485 _rtld_error("Can't find module with TLS index %d", index); 4486 die(); 4487 } 4488 4489 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4490 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4491 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4492 4493 return p; 4494} 4495 4496bool 4497allocate_tls_offset(Obj_Entry *obj) 4498{ 4499 size_t off; 4500 4501 if (obj->tls_done) 4502 return true; 4503 4504 if (obj->tlssize == 0) { 4505 obj->tls_done = true; 4506 return true; 4507 } 4508 4509 if (obj->tlsindex == 1) 4510 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4511 else 4512 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4513 obj->tlssize, obj->tlsalign); 4514 4515 /* 4516 * If we have already fixed the size of the static TLS block, we 4517 * must stay within that size. When allocating the static TLS, we 4518 * leave a small amount of space spare to be used for dynamically 4519 * loading modules which use static TLS. 4520 */ 4521 if (tls_static_space != 0) { 4522 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4523 return false; 4524 } else if (obj->tlsalign > tls_static_max_align) { 4525 tls_static_max_align = obj->tlsalign; 4526 } 4527 4528 tls_last_offset = obj->tlsoffset = off; 4529 tls_last_size = obj->tlssize; 4530 obj->tls_done = true; 4531 4532 return true; 4533} 4534 4535void 4536free_tls_offset(Obj_Entry *obj) 4537{ 4538 4539 /* 4540 * If we were the last thing to allocate out of the static TLS 4541 * block, we give our space back to the 'allocator'. This is a 4542 * simplistic workaround to allow libGL.so.1 to be loaded and 4543 * unloaded multiple times. 4544 */ 4545 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4546 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4547 tls_last_offset -= obj->tlssize; 4548 tls_last_size = 0; 4549 } 4550} 4551 4552void * 4553_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4554{ 4555 void *ret; 4556 RtldLockState lockstate; 4557 4558 wlock_acquire(rtld_bind_lock, &lockstate); 4559 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4560 lock_release(rtld_bind_lock, &lockstate); 4561 return (ret); 4562} 4563 4564void 4565_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4566{ 4567 RtldLockState lockstate; 4568 4569 wlock_acquire(rtld_bind_lock, &lockstate); 4570 free_tls(tcb, tcbsize, tcbalign); 4571 lock_release(rtld_bind_lock, &lockstate); 4572} 4573 4574static void 4575object_add_name(Obj_Entry *obj, const char *name) 4576{ 4577 Name_Entry *entry; 4578 size_t len; 4579 4580 len = strlen(name); 4581 entry = malloc(sizeof(Name_Entry) + len); 4582 4583 if (entry != NULL) { 4584 strcpy(entry->name, name); 4585 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4586 } 4587} 4588 4589static int 4590object_match_name(const Obj_Entry *obj, const char *name) 4591{ 4592 Name_Entry *entry; 4593 4594 STAILQ_FOREACH(entry, &obj->names, link) { 4595 if (strcmp(name, entry->name) == 0) 4596 return (1); 4597 } 4598 return (0); 4599} 4600 4601static Obj_Entry * 4602locate_dependency(const Obj_Entry *obj, const char *name) 4603{ 4604 const Objlist_Entry *entry; 4605 const Needed_Entry *needed; 4606 4607 STAILQ_FOREACH(entry, &list_main, link) { 4608 if (object_match_name(entry->obj, name)) 4609 return entry->obj; 4610 } 4611 4612 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4613 if (strcmp(obj->strtab + needed->name, name) == 0 || 4614 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4615 /* 4616 * If there is DT_NEEDED for the name we are looking for, 4617 * we are all set. Note that object might not be found if 4618 * dependency was not loaded yet, so the function can 4619 * return NULL here. This is expected and handled 4620 * properly by the caller. 4621 */ 4622 return (needed->obj); 4623 } 4624 } 4625 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4626 obj->path, name); 4627 die(); 4628} 4629 4630static int 4631check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4632 const Elf_Vernaux *vna) 4633{ 4634 const Elf_Verdef *vd; 4635 const char *vername; 4636 4637 vername = refobj->strtab + vna->vna_name; 4638 vd = depobj->verdef; 4639 if (vd == NULL) { 4640 _rtld_error("%s: version %s required by %s not defined", 4641 depobj->path, vername, refobj->path); 4642 return (-1); 4643 } 4644 for (;;) { 4645 if (vd->vd_version != VER_DEF_CURRENT) { 4646 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4647 depobj->path, vd->vd_version); 4648 return (-1); 4649 } 4650 if (vna->vna_hash == vd->vd_hash) { 4651 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4652 ((char *)vd + vd->vd_aux); 4653 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4654 return (0); 4655 } 4656 if (vd->vd_next == 0) 4657 break; 4658 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4659 } 4660 if (vna->vna_flags & VER_FLG_WEAK) 4661 return (0); 4662 _rtld_error("%s: version %s required by %s not found", 4663 depobj->path, vername, refobj->path); 4664 return (-1); 4665} 4666 4667static int 4668rtld_verify_object_versions(Obj_Entry *obj) 4669{ 4670 const Elf_Verneed *vn; 4671 const Elf_Verdef *vd; 4672 const Elf_Verdaux *vda; 4673 const Elf_Vernaux *vna; 4674 const Obj_Entry *depobj; 4675 int maxvernum, vernum; 4676 4677 if (obj->ver_checked) 4678 return (0); 4679 obj->ver_checked = true; 4680 4681 maxvernum = 0; 4682 /* 4683 * Walk over defined and required version records and figure out 4684 * max index used by any of them. Do very basic sanity checking 4685 * while there. 4686 */ 4687 vn = obj->verneed; 4688 while (vn != NULL) { 4689 if (vn->vn_version != VER_NEED_CURRENT) { 4690 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4691 obj->path, vn->vn_version); 4692 return (-1); 4693 } 4694 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4695 for (;;) { 4696 vernum = VER_NEED_IDX(vna->vna_other); 4697 if (vernum > maxvernum) 4698 maxvernum = vernum; 4699 if (vna->vna_next == 0) 4700 break; 4701 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4702 } 4703 if (vn->vn_next == 0) 4704 break; 4705 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4706 } 4707 4708 vd = obj->verdef; 4709 while (vd != NULL) { 4710 if (vd->vd_version != VER_DEF_CURRENT) { 4711 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4712 obj->path, vd->vd_version); 4713 return (-1); 4714 } 4715 vernum = VER_DEF_IDX(vd->vd_ndx); 4716 if (vernum > maxvernum) 4717 maxvernum = vernum; 4718 if (vd->vd_next == 0) 4719 break; 4720 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4721 } 4722 4723 if (maxvernum == 0) 4724 return (0); 4725 4726 /* 4727 * Store version information in array indexable by version index. 4728 * Verify that object version requirements are satisfied along the 4729 * way. 4730 */ 4731 obj->vernum = maxvernum + 1; 4732 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4733 4734 vd = obj->verdef; 4735 while (vd != NULL) { 4736 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4737 vernum = VER_DEF_IDX(vd->vd_ndx); 4738 assert(vernum <= maxvernum); 4739 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4740 obj->vertab[vernum].hash = vd->vd_hash; 4741 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4742 obj->vertab[vernum].file = NULL; 4743 obj->vertab[vernum].flags = 0; 4744 } 4745 if (vd->vd_next == 0) 4746 break; 4747 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4748 } 4749 4750 vn = obj->verneed; 4751 while (vn != NULL) { 4752 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4753 if (depobj == NULL) 4754 return (-1); 4755 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4756 for (;;) { 4757 if (check_object_provided_version(obj, depobj, vna)) 4758 return (-1); 4759 vernum = VER_NEED_IDX(vna->vna_other); 4760 assert(vernum <= maxvernum); 4761 obj->vertab[vernum].hash = vna->vna_hash; 4762 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4763 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4764 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4765 VER_INFO_HIDDEN : 0; 4766 if (vna->vna_next == 0) 4767 break; 4768 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4769 } 4770 if (vn->vn_next == 0) 4771 break; 4772 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4773 } 4774 return 0; 4775} 4776 4777static int 4778rtld_verify_versions(const Objlist *objlist) 4779{ 4780 Objlist_Entry *entry; 4781 int rc; 4782 4783 rc = 0; 4784 STAILQ_FOREACH(entry, objlist, link) { 4785 /* 4786 * Skip dummy objects or objects that have their version requirements 4787 * already checked. 4788 */ 4789 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4790 continue; 4791 if (rtld_verify_object_versions(entry->obj) == -1) { 4792 rc = -1; 4793 if (ld_tracing == NULL) 4794 break; 4795 } 4796 } 4797 if (rc == 0 || ld_tracing != NULL) 4798 rc = rtld_verify_object_versions(&obj_rtld); 4799 return rc; 4800} 4801 4802const Ver_Entry * 4803fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4804{ 4805 Elf_Versym vernum; 4806 4807 if (obj->vertab) { 4808 vernum = VER_NDX(obj->versyms[symnum]); 4809 if (vernum >= obj->vernum) { 4810 _rtld_error("%s: symbol %s has wrong verneed value %d", 4811 obj->path, obj->strtab + symnum, vernum); 4812 } else if (obj->vertab[vernum].hash != 0) { 4813 return &obj->vertab[vernum]; 4814 } 4815 } 4816 return NULL; 4817} 4818 4819int 4820_rtld_get_stack_prot(void) 4821{ 4822 4823 return (stack_prot); 4824} 4825 4826int 4827_rtld_is_dlopened(void *arg) 4828{ 4829 Obj_Entry *obj; 4830 RtldLockState lockstate; 4831 int res; 4832 4833 rlock_acquire(rtld_bind_lock, &lockstate); 4834 obj = dlcheck(arg); 4835 if (obj == NULL) 4836 obj = obj_from_addr(arg); 4837 if (obj == NULL) { 4838 _rtld_error("No shared object contains address"); 4839 lock_release(rtld_bind_lock, &lockstate); 4840 return (-1); 4841 } 4842 res = obj->dlopened ? 1 : 0; 4843 lock_release(rtld_bind_lock, &lockstate); 4844 return (res); 4845} 4846 4847static void 4848map_stacks_exec(RtldLockState *lockstate) 4849{ 4850 void (*thr_map_stacks_exec)(void); 4851 4852 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4853 return; 4854 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4855 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4856 if (thr_map_stacks_exec != NULL) { 4857 stack_prot |= PROT_EXEC; 4858 thr_map_stacks_exec(); 4859 } 4860} 4861 4862void 4863symlook_init(SymLook *dst, const char *name) 4864{ 4865 4866 bzero(dst, sizeof(*dst)); 4867 dst->name = name; 4868 dst->hash = elf_hash(name); 4869 dst->hash_gnu = gnu_hash(name); 4870} 4871 4872static void 4873symlook_init_from_req(SymLook *dst, const SymLook *src) 4874{ 4875 4876 dst->name = src->name; 4877 dst->hash = src->hash; 4878 dst->hash_gnu = src->hash_gnu; 4879 dst->ventry = src->ventry; 4880 dst->flags = src->flags; 4881 dst->defobj_out = NULL; 4882 dst->sym_out = NULL; 4883 dst->lockstate = src->lockstate; 4884} 4885 4886/* 4887 * Overrides for libc_pic-provided functions. 4888 */ 4889 4890int 4891__getosreldate(void) 4892{ 4893 size_t len; 4894 int oid[2]; 4895 int error, osrel; 4896 4897 if (osreldate != 0) 4898 return (osreldate); 4899 4900 oid[0] = CTL_KERN; 4901 oid[1] = KERN_OSRELDATE; 4902 osrel = 0; 4903 len = sizeof(osrel); 4904 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4905 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4906 osreldate = osrel; 4907 return (osreldate); 4908} 4909 4910void 4911exit(int status) 4912{ 4913 4914 _exit(status); 4915} 4916 4917void (*__cleanup)(void); 4918int __isthreaded = 0; 4919int _thread_autoinit_dummy_decl = 1; 4920 4921/* 4922 * No unresolved symbols for rtld. 4923 */ 4924void 4925__pthread_cxa_finalize(struct dl_phdr_info *a) 4926{ 4927} 4928 4929void 4930__stack_chk_fail(void) 4931{ 4932 4933 _rtld_error("stack overflow detected; terminated"); 4934 die(); 4935} 4936__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 4937 4938void 4939__chk_fail(void) 4940{ 4941 4942 _rtld_error("buffer overflow detected; terminated"); 4943 die(); 4944} 4945 4946const char * 4947rtld_strerror(int errnum) 4948{ 4949 4950 if (errnum < 0 || errnum >= sys_nerr) 4951 return ("Unknown error"); 4952 return (sys_errlist[errnum]); 4953} 4954