rtld.c revision 312402
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 312402 2017-01-19 06:48:03Z kib $ 29 */ 30 31/* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37#include <sys/param.h> 38#include <sys/mount.h> 39#include <sys/mman.h> 40#include <sys/stat.h> 41#include <sys/sysctl.h> 42#include <sys/uio.h> 43#include <sys/utsname.h> 44#include <sys/ktrace.h> 45 46#include <dlfcn.h> 47#include <err.h> 48#include <errno.h> 49#include <fcntl.h> 50#include <stdarg.h> 51#include <stdio.h> 52#include <stdlib.h> 53#include <string.h> 54#include <unistd.h> 55 56#include "debug.h" 57#include "rtld.h" 58#include "libmap.h" 59#include "rtld_tls.h" 60#include "rtld_printf.h" 61#include "notes.h" 62 63#ifndef COMPAT_32BIT 64#define PATH_RTLD "/libexec/ld-elf.so.1" 65#else 66#define PATH_RTLD "/libexec/ld-elf32.so.1" 67#endif 68 69/* Types. */ 70typedef void (*func_ptr_type)(); 71typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73/* 74 * Function declarations. 75 */ 76static const char *basename(const char *); 77static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 78 const Elf_Dyn **, const Elf_Dyn **); 79static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 80 const Elf_Dyn *); 81static void digest_dynamic(Obj_Entry *, int); 82static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 83static Obj_Entry *dlcheck(void *); 84static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 85 int lo_flags, int mode, RtldLockState *lockstate); 86static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 87static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 88static bool donelist_check(DoneList *, const Obj_Entry *); 89static void errmsg_restore(char *); 90static char *errmsg_save(void); 91static void *fill_search_info(const char *, size_t, void *); 92static char *find_library(const char *, const Obj_Entry *); 93static const char *gethints(bool); 94static void init_dag(Obj_Entry *); 95static void init_pagesizes(Elf_Auxinfo **aux_info); 96static void init_rtld(caddr_t, Elf_Auxinfo **); 97static void initlist_add_neededs(Needed_Entry *, Objlist *); 98static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *); 99static void linkmap_add(Obj_Entry *); 100static void linkmap_delete(Obj_Entry *); 101static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 102static void unload_filtees(Obj_Entry *); 103static int load_needed_objects(Obj_Entry *, int); 104static int load_preload_objects(void); 105static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 106static void map_stacks_exec(RtldLockState *); 107static int obj_enforce_relro(Obj_Entry *); 108static Obj_Entry *obj_from_addr(const void *); 109static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 110static void objlist_call_init(Objlist *, RtldLockState *); 111static void objlist_clear(Objlist *); 112static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 113static void objlist_init(Objlist *); 114static void objlist_push_head(Objlist *, Obj_Entry *); 115static void objlist_push_tail(Objlist *, Obj_Entry *); 116static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 117static void objlist_remove(Objlist *, Obj_Entry *); 118static void *path_enumerate(const char *, path_enum_proc, void *); 119static int relocate_object_dag(Obj_Entry *root, bool bind_now, 120 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 121static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 122 int flags, RtldLockState *lockstate); 123static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 124 RtldLockState *); 125static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 126 int flags, RtldLockState *lockstate); 127static int rtld_dirname(const char *, char *); 128static int rtld_dirname_abs(const char *, char *); 129static void *rtld_dlopen(const char *name, int fd, int mode); 130static void rtld_exit(void); 131static char *search_library_path(const char *, const char *); 132static const void **get_program_var_addr(const char *, RtldLockState *); 133static void set_program_var(const char *, const void *); 134static int symlook_default(SymLook *, const Obj_Entry *refobj); 135static int symlook_global(SymLook *, DoneList *); 136static void symlook_init_from_req(SymLook *, const SymLook *); 137static int symlook_list(SymLook *, const Objlist *, DoneList *); 138static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 139static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 140static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 141static void trace_loaded_objects(Obj_Entry *); 142static void unlink_object(Obj_Entry *); 143static void unload_object(Obj_Entry *); 144static void unref_dag(Obj_Entry *); 145static void ref_dag(Obj_Entry *); 146static char *origin_subst_one(Obj_Entry *, char *, const char *, 147 const char *, bool); 148static char *origin_subst(Obj_Entry *, char *); 149static bool obj_resolve_origin(Obj_Entry *obj); 150static void preinit_main(void); 151static int rtld_verify_versions(const Objlist *); 152static int rtld_verify_object_versions(Obj_Entry *); 153static void object_add_name(Obj_Entry *, const char *); 154static int object_match_name(const Obj_Entry *, const char *); 155static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 156static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 157 struct dl_phdr_info *phdr_info); 158static uint32_t gnu_hash(const char *); 159static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 160 const unsigned long); 161 162void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 163void _r_debug_postinit(struct link_map *) __noinline __exported; 164 165/* 166 * Data declarations. 167 */ 168static char *error_message; /* Message for dlerror(), or NULL */ 169struct r_debug r_debug __exported; /* for GDB; */ 170static bool libmap_disable; /* Disable libmap */ 171static bool ld_loadfltr; /* Immediate filters processing */ 172static char *libmap_override; /* Maps to use in addition to libmap.conf */ 173static bool trust; /* False for setuid and setgid programs */ 174static bool dangerous_ld_env; /* True if environment variables have been 175 used to affect the libraries loaded */ 176static char *ld_bind_now; /* Environment variable for immediate binding */ 177static char *ld_debug; /* Environment variable for debugging */ 178static char *ld_library_path; /* Environment variable for search path */ 179static char *ld_preload; /* Environment variable for libraries to 180 load first */ 181static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 182static char *ld_tracing; /* Called from ldd to print libs */ 183static char *ld_utrace; /* Use utrace() to log events. */ 184static struct obj_entry_q obj_list; /* Queue of all loaded objects */ 185static Obj_Entry *obj_main; /* The main program shared object */ 186static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 187static unsigned int obj_count; /* Number of objects in obj_list */ 188static unsigned int obj_loads; /* Number of loads of objects (gen count) */ 189 190static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 191 STAILQ_HEAD_INITIALIZER(list_global); 192static Objlist list_main = /* Objects loaded at program startup */ 193 STAILQ_HEAD_INITIALIZER(list_main); 194static Objlist list_fini = /* Objects needing fini() calls */ 195 STAILQ_HEAD_INITIALIZER(list_fini); 196 197Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 198 199#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 200 201extern Elf_Dyn _DYNAMIC; 202#pragma weak _DYNAMIC 203#ifndef RTLD_IS_DYNAMIC 204#define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 205#endif 206 207int dlclose(void *) __exported; 208char *dlerror(void) __exported; 209void *dlopen(const char *, int) __exported; 210void *fdlopen(int, int) __exported; 211void *dlsym(void *, const char *) __exported; 212dlfunc_t dlfunc(void *, const char *) __exported; 213void *dlvsym(void *, const char *, const char *) __exported; 214int dladdr(const void *, Dl_info *) __exported; 215void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 216 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 217int dlinfo(void *, int , void *) __exported; 218int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 219int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 220int _rtld_get_stack_prot(void) __exported; 221int _rtld_is_dlopened(void *) __exported; 222void _rtld_error(const char *, ...) __exported; 223 224int npagesizes, osreldate; 225size_t *pagesizes; 226 227long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 228 229static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 230static int max_stack_flags; 231 232/* 233 * Global declarations normally provided by crt1. The dynamic linker is 234 * not built with crt1, so we have to provide them ourselves. 235 */ 236char *__progname; 237char **environ; 238 239/* 240 * Used to pass argc, argv to init functions. 241 */ 242int main_argc; 243char **main_argv; 244 245/* 246 * Globals to control TLS allocation. 247 */ 248size_t tls_last_offset; /* Static TLS offset of last module */ 249size_t tls_last_size; /* Static TLS size of last module */ 250size_t tls_static_space; /* Static TLS space allocated */ 251size_t tls_static_max_align; 252int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 253int tls_max_index = 1; /* Largest module index allocated */ 254 255bool ld_library_path_rpath = false; 256 257/* 258 * Fill in a DoneList with an allocation large enough to hold all of 259 * the currently-loaded objects. Keep this as a macro since it calls 260 * alloca and we want that to occur within the scope of the caller. 261 */ 262#define donelist_init(dlp) \ 263 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 264 assert((dlp)->objs != NULL), \ 265 (dlp)->num_alloc = obj_count, \ 266 (dlp)->num_used = 0) 267 268#define UTRACE_DLOPEN_START 1 269#define UTRACE_DLOPEN_STOP 2 270#define UTRACE_DLCLOSE_START 3 271#define UTRACE_DLCLOSE_STOP 4 272#define UTRACE_LOAD_OBJECT 5 273#define UTRACE_UNLOAD_OBJECT 6 274#define UTRACE_ADD_RUNDEP 7 275#define UTRACE_PRELOAD_FINISHED 8 276#define UTRACE_INIT_CALL 9 277#define UTRACE_FINI_CALL 10 278#define UTRACE_DLSYM_START 11 279#define UTRACE_DLSYM_STOP 12 280 281struct utrace_rtld { 282 char sig[4]; /* 'RTLD' */ 283 int event; 284 void *handle; 285 void *mapbase; /* Used for 'parent' and 'init/fini' */ 286 size_t mapsize; 287 int refcnt; /* Used for 'mode' */ 288 char name[MAXPATHLEN]; 289}; 290 291#define LD_UTRACE(e, h, mb, ms, r, n) do { \ 292 if (ld_utrace != NULL) \ 293 ld_utrace_log(e, h, mb, ms, r, n); \ 294} while (0) 295 296static void 297ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 298 int refcnt, const char *name) 299{ 300 struct utrace_rtld ut; 301 302 ut.sig[0] = 'R'; 303 ut.sig[1] = 'T'; 304 ut.sig[2] = 'L'; 305 ut.sig[3] = 'D'; 306 ut.event = event; 307 ut.handle = handle; 308 ut.mapbase = mapbase; 309 ut.mapsize = mapsize; 310 ut.refcnt = refcnt; 311 bzero(ut.name, sizeof(ut.name)); 312 if (name) 313 strlcpy(ut.name, name, sizeof(ut.name)); 314 utrace(&ut, sizeof(ut)); 315} 316 317/* 318 * Main entry point for dynamic linking. The first argument is the 319 * stack pointer. The stack is expected to be laid out as described 320 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 321 * Specifically, the stack pointer points to a word containing 322 * ARGC. Following that in the stack is a null-terminated sequence 323 * of pointers to argument strings. Then comes a null-terminated 324 * sequence of pointers to environment strings. Finally, there is a 325 * sequence of "auxiliary vector" entries. 326 * 327 * The second argument points to a place to store the dynamic linker's 328 * exit procedure pointer and the third to a place to store the main 329 * program's object. 330 * 331 * The return value is the main program's entry point. 332 */ 333func_ptr_type 334_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 335{ 336 Elf_Auxinfo *aux_info[AT_COUNT]; 337 int i; 338 int argc; 339 char **argv; 340 char **env; 341 Elf_Auxinfo *aux; 342 Elf_Auxinfo *auxp; 343 const char *argv0; 344 Objlist_Entry *entry; 345 Obj_Entry *obj; 346 Obj_Entry *preload_tail; 347 Obj_Entry *last_interposer; 348 Objlist initlist; 349 RtldLockState lockstate; 350 char *library_path_rpath; 351 int mib[2]; 352 size_t len; 353 354 /* 355 * On entry, the dynamic linker itself has not been relocated yet. 356 * Be very careful not to reference any global data until after 357 * init_rtld has returned. It is OK to reference file-scope statics 358 * and string constants, and to call static and global functions. 359 */ 360 361 /* Find the auxiliary vector on the stack. */ 362 argc = *sp++; 363 argv = (char **) sp; 364 sp += argc + 1; /* Skip over arguments and NULL terminator */ 365 env = (char **) sp; 366 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 367 ; 368 aux = (Elf_Auxinfo *) sp; 369 370 /* Digest the auxiliary vector. */ 371 for (i = 0; i < AT_COUNT; i++) 372 aux_info[i] = NULL; 373 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 374 if (auxp->a_type < AT_COUNT) 375 aux_info[auxp->a_type] = auxp; 376 } 377 378 /* Initialize and relocate ourselves. */ 379 assert(aux_info[AT_BASE] != NULL); 380 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 381 382 __progname = obj_rtld.path; 383 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 384 environ = env; 385 main_argc = argc; 386 main_argv = argv; 387 388 if (aux_info[AT_CANARY] != NULL && 389 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 390 i = aux_info[AT_CANARYLEN]->a_un.a_val; 391 if (i > sizeof(__stack_chk_guard)) 392 i = sizeof(__stack_chk_guard); 393 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 394 } else { 395 mib[0] = CTL_KERN; 396 mib[1] = KERN_ARND; 397 398 len = sizeof(__stack_chk_guard); 399 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 400 len != sizeof(__stack_chk_guard)) { 401 /* If sysctl was unsuccessful, use the "terminator canary". */ 402 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 403 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 404 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 405 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 406 } 407 } 408 409 trust = !issetugid(); 410 411 ld_bind_now = getenv(LD_ "BIND_NOW"); 412 /* 413 * If the process is tainted, then we un-set the dangerous environment 414 * variables. The process will be marked as tainted until setuid(2) 415 * is called. If any child process calls setuid(2) we do not want any 416 * future processes to honor the potentially un-safe variables. 417 */ 418 if (!trust) { 419 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 420 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") || 421 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 422 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 423 _rtld_error("environment corrupt; aborting"); 424 rtld_die(); 425 } 426 } 427 ld_debug = getenv(LD_ "DEBUG"); 428 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 429 libmap_override = getenv(LD_ "LIBMAP"); 430 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 431 ld_preload = getenv(LD_ "PRELOAD"); 432 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 433 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 434 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 435 if (library_path_rpath != NULL) { 436 if (library_path_rpath[0] == 'y' || 437 library_path_rpath[0] == 'Y' || 438 library_path_rpath[0] == '1') 439 ld_library_path_rpath = true; 440 else 441 ld_library_path_rpath = false; 442 } 443 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 444 (ld_library_path != NULL) || (ld_preload != NULL) || 445 (ld_elf_hints_path != NULL) || ld_loadfltr; 446 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 447 ld_utrace = getenv(LD_ "UTRACE"); 448 449 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 450 ld_elf_hints_path = _PATH_ELF_HINTS; 451 452 if (ld_debug != NULL && *ld_debug != '\0') 453 debug = 1; 454 dbg("%s is initialized, base address = %p", __progname, 455 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 456 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 457 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 458 459 dbg("initializing thread locks"); 460 lockdflt_init(); 461 462 /* 463 * Load the main program, or process its program header if it is 464 * already loaded. 465 */ 466 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 467 int fd = aux_info[AT_EXECFD]->a_un.a_val; 468 dbg("loading main program"); 469 obj_main = map_object(fd, argv0, NULL); 470 close(fd); 471 if (obj_main == NULL) 472 rtld_die(); 473 max_stack_flags = obj->stack_flags; 474 } else { /* Main program already loaded. */ 475 const Elf_Phdr *phdr; 476 int phnum; 477 caddr_t entry; 478 479 dbg("processing main program's program header"); 480 assert(aux_info[AT_PHDR] != NULL); 481 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 482 assert(aux_info[AT_PHNUM] != NULL); 483 phnum = aux_info[AT_PHNUM]->a_un.a_val; 484 assert(aux_info[AT_PHENT] != NULL); 485 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 486 assert(aux_info[AT_ENTRY] != NULL); 487 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 488 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 489 rtld_die(); 490 } 491 492 if (aux_info[AT_EXECPATH] != 0) { 493 char *kexecpath; 494 char buf[MAXPATHLEN]; 495 496 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 497 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 498 if (kexecpath[0] == '/') 499 obj_main->path = kexecpath; 500 else if (getcwd(buf, sizeof(buf)) == NULL || 501 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 502 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 503 obj_main->path = xstrdup(argv0); 504 else 505 obj_main->path = xstrdup(buf); 506 } else { 507 dbg("No AT_EXECPATH"); 508 obj_main->path = xstrdup(argv0); 509 } 510 dbg("obj_main path %s", obj_main->path); 511 obj_main->mainprog = true; 512 513 if (aux_info[AT_STACKPROT] != NULL && 514 aux_info[AT_STACKPROT]->a_un.a_val != 0) 515 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 516 517#ifndef COMPAT_32BIT 518 /* 519 * Get the actual dynamic linker pathname from the executable if 520 * possible. (It should always be possible.) That ensures that 521 * gdb will find the right dynamic linker even if a non-standard 522 * one is being used. 523 */ 524 if (obj_main->interp != NULL && 525 strcmp(obj_main->interp, obj_rtld.path) != 0) { 526 free(obj_rtld.path); 527 obj_rtld.path = xstrdup(obj_main->interp); 528 __progname = obj_rtld.path; 529 } 530#endif 531 532 digest_dynamic(obj_main, 0); 533 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 534 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 535 obj_main->dynsymcount); 536 537 linkmap_add(obj_main); 538 linkmap_add(&obj_rtld); 539 540 /* Link the main program into the list of objects. */ 541 TAILQ_INSERT_HEAD(&obj_list, obj_main, next); 542 obj_count++; 543 obj_loads++; 544 545 /* Initialize a fake symbol for resolving undefined weak references. */ 546 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 547 sym_zero.st_shndx = SHN_UNDEF; 548 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 549 550 if (!libmap_disable) 551 libmap_disable = (bool)lm_init(libmap_override); 552 553 dbg("loading LD_PRELOAD libraries"); 554 if (load_preload_objects() == -1) 555 rtld_die(); 556 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 557 558 dbg("loading needed objects"); 559 if (load_needed_objects(obj_main, 0) == -1) 560 rtld_die(); 561 562 /* Make a list of all objects loaded at startup. */ 563 last_interposer = obj_main; 564 TAILQ_FOREACH(obj, &obj_list, next) { 565 if (obj->marker) 566 continue; 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 rtld_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 rtld_die(); 608 609 dbg("doing copy relocations"); 610 if (do_copy_relocations(obj_main) == -1) 611 rtld_die(); 612 613 dbg("enforcing main obj relro"); 614 if (obj_enforce_relro(obj_main) == -1) 615 rtld_die(); 616 617 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 618 dump_relocations(obj_main); 619 exit (0); 620 } 621 622 /* 623 * Setup TLS for main thread. This must be done after the 624 * relocations are processed, since tls initialization section 625 * might be the subject for relocations. 626 */ 627 dbg("initializing initial thread local storage"); 628 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); 629 630 dbg("initializing key program variables"); 631 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 632 set_program_var("environ", env); 633 set_program_var("__elf_aux_vector", aux); 634 635 /* Make a list of init functions to call. */ 636 objlist_init(&initlist); 637 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)), 638 preload_tail, &initlist); 639 640 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 641 642 map_stacks_exec(NULL); 643 ifunc_init(aux); 644 645 dbg("resolving ifuncs"); 646 if (resolve_objects_ifunc(obj_main, 647 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 648 NULL) == -1) 649 rtld_die(); 650 651 if (!obj_main->crt_no_init) { 652 /* 653 * Make sure we don't call the main program's init and fini 654 * functions for binaries linked with old crt1 which calls 655 * _init itself. 656 */ 657 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 658 obj_main->preinit_array = obj_main->init_array = 659 obj_main->fini_array = (Elf_Addr)NULL; 660 } 661 662 wlock_acquire(rtld_bind_lock, &lockstate); 663 if (obj_main->crt_no_init) 664 preinit_main(); 665 objlist_call_init(&initlist, &lockstate); 666 _r_debug_postinit(&obj_main->linkmap); 667 objlist_clear(&initlist); 668 dbg("loading filtees"); 669 TAILQ_FOREACH(obj, &obj_list, next) { 670 if (obj->marker) 671 continue; 672 if (ld_loadfltr || obj->z_loadfltr) 673 load_filtees(obj, 0, &lockstate); 674 } 675 lock_release(rtld_bind_lock, &lockstate); 676 677 dbg("transferring control to program entry point = %p", obj_main->entry); 678 679 /* Return the exit procedure and the program entry point. */ 680 *exit_proc = rtld_exit; 681 *objp = obj_main; 682 return (func_ptr_type) obj_main->entry; 683} 684 685void * 686rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 687{ 688 void *ptr; 689 Elf_Addr target; 690 691 ptr = (void *)make_function_pointer(def, obj); 692 target = call_ifunc_resolver(ptr); 693 return ((void *)target); 694} 695 696Elf_Addr 697_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 698{ 699 const Elf_Rel *rel; 700 const Elf_Sym *def; 701 const Obj_Entry *defobj; 702 Elf_Addr *where; 703 Elf_Addr target; 704 RtldLockState lockstate; 705 706 rlock_acquire(rtld_bind_lock, &lockstate); 707 if (sigsetjmp(lockstate.env, 0) != 0) 708 lock_upgrade(rtld_bind_lock, &lockstate); 709 if (obj->pltrel) 710 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 711 else 712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 713 714 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 715 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 716 NULL, &lockstate); 717 if (def == NULL) 718 rtld_die(); 719 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 720 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 721 else 722 target = (Elf_Addr)(defobj->relocbase + def->st_value); 723 724 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 725 defobj->strtab + def->st_name, basename(obj->path), 726 (void *)target, basename(defobj->path)); 727 728 /* 729 * Write the new contents for the jmpslot. Note that depending on 730 * architecture, the value which we need to return back to the 731 * lazy binding trampoline may or may not be the target 732 * address. The value returned from reloc_jmpslot() is the value 733 * that the trampoline needs. 734 */ 735 target = reloc_jmpslot(where, target, defobj, obj, rel); 736 lock_release(rtld_bind_lock, &lockstate); 737 return target; 738} 739 740/* 741 * Error reporting function. Use it like printf. If formats the message 742 * into a buffer, and sets things up so that the next call to dlerror() 743 * will return the message. 744 */ 745void 746_rtld_error(const char *fmt, ...) 747{ 748 static char buf[512]; 749 va_list ap; 750 751 va_start(ap, fmt); 752 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 753 error_message = buf; 754 va_end(ap); 755} 756 757/* 758 * Return a dynamically-allocated copy of the current error message, if any. 759 */ 760static char * 761errmsg_save(void) 762{ 763 return error_message == NULL ? NULL : xstrdup(error_message); 764} 765 766/* 767 * Restore the current error message from a copy which was previously saved 768 * by errmsg_save(). The copy is freed. 769 */ 770static void 771errmsg_restore(char *saved_msg) 772{ 773 if (saved_msg == NULL) 774 error_message = NULL; 775 else { 776 _rtld_error("%s", saved_msg); 777 free(saved_msg); 778 } 779} 780 781static const char * 782basename(const char *name) 783{ 784 const char *p = strrchr(name, '/'); 785 return p != NULL ? p + 1 : name; 786} 787 788static struct utsname uts; 789 790static char * 791origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 792 const char *subst, bool may_free) 793{ 794 char *p, *p1, *res, *resp; 795 int subst_len, kw_len, subst_count, old_len, new_len; 796 797 kw_len = strlen(kw); 798 799 /* 800 * First, count the number of the keyword occurences, to 801 * preallocate the final string. 802 */ 803 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 804 p1 = strstr(p, kw); 805 if (p1 == NULL) 806 break; 807 } 808 809 /* 810 * If the keyword is not found, just return. 811 * 812 * Return non-substituted string if resolution failed. We 813 * cannot do anything more reasonable, the failure mode of the 814 * caller is unresolved library anyway. 815 */ 816 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 817 return (may_free ? real : xstrdup(real)); 818 if (obj != NULL) 819 subst = obj->origin_path; 820 821 /* 822 * There is indeed something to substitute. Calculate the 823 * length of the resulting string, and allocate it. 824 */ 825 subst_len = strlen(subst); 826 old_len = strlen(real); 827 new_len = old_len + (subst_len - kw_len) * subst_count; 828 res = xmalloc(new_len + 1); 829 830 /* 831 * Now, execute the substitution loop. 832 */ 833 for (p = real, resp = res, *resp = '\0';;) { 834 p1 = strstr(p, kw); 835 if (p1 != NULL) { 836 /* Copy the prefix before keyword. */ 837 memcpy(resp, p, p1 - p); 838 resp += p1 - p; 839 /* Keyword replacement. */ 840 memcpy(resp, subst, subst_len); 841 resp += subst_len; 842 *resp = '\0'; 843 p = p1 + kw_len; 844 } else 845 break; 846 } 847 848 /* Copy to the end of string and finish. */ 849 strcat(resp, p); 850 if (may_free) 851 free(real); 852 return (res); 853} 854 855static char * 856origin_subst(Obj_Entry *obj, char *real) 857{ 858 char *res1, *res2, *res3, *res4; 859 860 if (obj == NULL || !trust) 861 return (xstrdup(real)); 862 if (uts.sysname[0] == '\0') { 863 if (uname(&uts) != 0) { 864 _rtld_error("utsname failed: %d", errno); 865 return (NULL); 866 } 867 } 868 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 869 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 870 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 871 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 872 return (res4); 873} 874 875void 876rtld_die(void) 877{ 878 const char *msg = dlerror(); 879 880 if (msg == NULL) 881 msg = "Fatal error"; 882 rtld_fdputstr(STDERR_FILENO, msg); 883 rtld_fdputchar(STDERR_FILENO, '\n'); 884 _exit(1); 885} 886 887/* 888 * Process a shared object's DYNAMIC section, and save the important 889 * information in its Obj_Entry structure. 890 */ 891static void 892digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 893 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 894{ 895 const Elf_Dyn *dynp; 896 Needed_Entry **needed_tail = &obj->needed; 897 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 898 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 899 const Elf_Hashelt *hashtab; 900 const Elf32_Word *hashval; 901 Elf32_Word bkt, nmaskwords; 902 int bloom_size32; 903 int plttype = DT_REL; 904 905 *dyn_rpath = NULL; 906 *dyn_soname = NULL; 907 *dyn_runpath = NULL; 908 909 obj->bind_now = false; 910 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 911 switch (dynp->d_tag) { 912 913 case DT_REL: 914 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 915 break; 916 917 case DT_RELSZ: 918 obj->relsize = dynp->d_un.d_val; 919 break; 920 921 case DT_RELENT: 922 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 923 break; 924 925 case DT_JMPREL: 926 obj->pltrel = (const Elf_Rel *) 927 (obj->relocbase + dynp->d_un.d_ptr); 928 break; 929 930 case DT_PLTRELSZ: 931 obj->pltrelsize = dynp->d_un.d_val; 932 break; 933 934 case DT_RELA: 935 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 936 break; 937 938 case DT_RELASZ: 939 obj->relasize = dynp->d_un.d_val; 940 break; 941 942 case DT_RELAENT: 943 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 944 break; 945 946 case DT_PLTREL: 947 plttype = dynp->d_un.d_val; 948 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 949 break; 950 951 case DT_SYMTAB: 952 obj->symtab = (const Elf_Sym *) 953 (obj->relocbase + dynp->d_un.d_ptr); 954 break; 955 956 case DT_SYMENT: 957 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 958 break; 959 960 case DT_STRTAB: 961 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 962 break; 963 964 case DT_STRSZ: 965 obj->strsize = dynp->d_un.d_val; 966 break; 967 968 case DT_VERNEED: 969 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 970 dynp->d_un.d_val); 971 break; 972 973 case DT_VERNEEDNUM: 974 obj->verneednum = dynp->d_un.d_val; 975 break; 976 977 case DT_VERDEF: 978 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 979 dynp->d_un.d_val); 980 break; 981 982 case DT_VERDEFNUM: 983 obj->verdefnum = dynp->d_un.d_val; 984 break; 985 986 case DT_VERSYM: 987 obj->versyms = (const Elf_Versym *)(obj->relocbase + 988 dynp->d_un.d_val); 989 break; 990 991 case DT_HASH: 992 { 993 hashtab = (const Elf_Hashelt *)(obj->relocbase + 994 dynp->d_un.d_ptr); 995 obj->nbuckets = hashtab[0]; 996 obj->nchains = hashtab[1]; 997 obj->buckets = hashtab + 2; 998 obj->chains = obj->buckets + obj->nbuckets; 999 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1000 obj->buckets != NULL; 1001 } 1002 break; 1003 1004 case DT_GNU_HASH: 1005 { 1006 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1007 dynp->d_un.d_ptr); 1008 obj->nbuckets_gnu = hashtab[0]; 1009 obj->symndx_gnu = hashtab[1]; 1010 nmaskwords = hashtab[2]; 1011 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1012 obj->maskwords_bm_gnu = nmaskwords - 1; 1013 obj->shift2_gnu = hashtab[3]; 1014 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1015 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1016 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1017 obj->symndx_gnu; 1018 /* Number of bitmask words is required to be power of 2 */ 1019 obj->valid_hash_gnu = powerof2(nmaskwords) && 1020 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1021 } 1022 break; 1023 1024 case DT_NEEDED: 1025 if (!obj->rtld) { 1026 Needed_Entry *nep = NEW(Needed_Entry); 1027 nep->name = dynp->d_un.d_val; 1028 nep->obj = NULL; 1029 nep->next = NULL; 1030 1031 *needed_tail = nep; 1032 needed_tail = &nep->next; 1033 } 1034 break; 1035 1036 case DT_FILTER: 1037 if (!obj->rtld) { 1038 Needed_Entry *nep = NEW(Needed_Entry); 1039 nep->name = dynp->d_un.d_val; 1040 nep->obj = NULL; 1041 nep->next = NULL; 1042 1043 *needed_filtees_tail = nep; 1044 needed_filtees_tail = &nep->next; 1045 } 1046 break; 1047 1048 case DT_AUXILIARY: 1049 if (!obj->rtld) { 1050 Needed_Entry *nep = NEW(Needed_Entry); 1051 nep->name = dynp->d_un.d_val; 1052 nep->obj = NULL; 1053 nep->next = NULL; 1054 1055 *needed_aux_filtees_tail = nep; 1056 needed_aux_filtees_tail = &nep->next; 1057 } 1058 break; 1059 1060 case DT_PLTGOT: 1061 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1062 break; 1063 1064 case DT_TEXTREL: 1065 obj->textrel = true; 1066 break; 1067 1068 case DT_SYMBOLIC: 1069 obj->symbolic = true; 1070 break; 1071 1072 case DT_RPATH: 1073 /* 1074 * We have to wait until later to process this, because we 1075 * might not have gotten the address of the string table yet. 1076 */ 1077 *dyn_rpath = dynp; 1078 break; 1079 1080 case DT_SONAME: 1081 *dyn_soname = dynp; 1082 break; 1083 1084 case DT_RUNPATH: 1085 *dyn_runpath = dynp; 1086 break; 1087 1088 case DT_INIT: 1089 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1090 break; 1091 1092 case DT_PREINIT_ARRAY: 1093 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1094 break; 1095 1096 case DT_PREINIT_ARRAYSZ: 1097 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1098 break; 1099 1100 case DT_INIT_ARRAY: 1101 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1102 break; 1103 1104 case DT_INIT_ARRAYSZ: 1105 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1106 break; 1107 1108 case DT_FINI: 1109 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1110 break; 1111 1112 case DT_FINI_ARRAY: 1113 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1114 break; 1115 1116 case DT_FINI_ARRAYSZ: 1117 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1118 break; 1119 1120 /* 1121 * Don't process DT_DEBUG on MIPS as the dynamic section 1122 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1123 */ 1124 1125#ifndef __mips__ 1126 case DT_DEBUG: 1127 if (!early) 1128 dbg("Filling in DT_DEBUG entry"); 1129 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1130 break; 1131#endif 1132 1133 case DT_FLAGS: 1134 if (dynp->d_un.d_val & DF_ORIGIN) 1135 obj->z_origin = true; 1136 if (dynp->d_un.d_val & DF_SYMBOLIC) 1137 obj->symbolic = true; 1138 if (dynp->d_un.d_val & DF_TEXTREL) 1139 obj->textrel = true; 1140 if (dynp->d_un.d_val & DF_BIND_NOW) 1141 obj->bind_now = true; 1142 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1143 ;*/ 1144 break; 1145#ifdef __mips__ 1146 case DT_MIPS_LOCAL_GOTNO: 1147 obj->local_gotno = dynp->d_un.d_val; 1148 break; 1149 1150 case DT_MIPS_SYMTABNO: 1151 obj->symtabno = dynp->d_un.d_val; 1152 break; 1153 1154 case DT_MIPS_GOTSYM: 1155 obj->gotsym = dynp->d_un.d_val; 1156 break; 1157 1158 case DT_MIPS_RLD_MAP: 1159 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1160 break; 1161#endif 1162 1163 case DT_FLAGS_1: 1164 if (dynp->d_un.d_val & DF_1_NOOPEN) 1165 obj->z_noopen = true; 1166 if (dynp->d_un.d_val & DF_1_ORIGIN) 1167 obj->z_origin = true; 1168 if (dynp->d_un.d_val & DF_1_GLOBAL) 1169 obj->z_global = true; 1170 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1171 obj->bind_now = true; 1172 if (dynp->d_un.d_val & DF_1_NODELETE) 1173 obj->z_nodelete = true; 1174 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1175 obj->z_loadfltr = true; 1176 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1177 obj->z_interpose = true; 1178 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1179 obj->z_nodeflib = true; 1180 break; 1181 1182 default: 1183 if (!early) { 1184 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1185 (long)dynp->d_tag); 1186 } 1187 break; 1188 } 1189 } 1190 1191 obj->traced = false; 1192 1193 if (plttype == DT_RELA) { 1194 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1195 obj->pltrel = NULL; 1196 obj->pltrelasize = obj->pltrelsize; 1197 obj->pltrelsize = 0; 1198 } 1199 1200 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1201 if (obj->valid_hash_sysv) 1202 obj->dynsymcount = obj->nchains; 1203 else if (obj->valid_hash_gnu) { 1204 obj->dynsymcount = 0; 1205 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1206 if (obj->buckets_gnu[bkt] == 0) 1207 continue; 1208 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1209 do 1210 obj->dynsymcount++; 1211 while ((*hashval++ & 1u) == 0); 1212 } 1213 obj->dynsymcount += obj->symndx_gnu; 1214 } 1215} 1216 1217static bool 1218obj_resolve_origin(Obj_Entry *obj) 1219{ 1220 1221 if (obj->origin_path != NULL) 1222 return (true); 1223 obj->origin_path = xmalloc(PATH_MAX); 1224 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1225} 1226 1227static void 1228digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1229 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1230{ 1231 1232 if (obj->z_origin && !obj_resolve_origin(obj)) 1233 rtld_die(); 1234 1235 if (dyn_runpath != NULL) { 1236 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1237 obj->runpath = origin_subst(obj, obj->runpath); 1238 } else if (dyn_rpath != NULL) { 1239 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1240 obj->rpath = origin_subst(obj, obj->rpath); 1241 } 1242 if (dyn_soname != NULL) 1243 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1244} 1245 1246static void 1247digest_dynamic(Obj_Entry *obj, int early) 1248{ 1249 const Elf_Dyn *dyn_rpath; 1250 const Elf_Dyn *dyn_soname; 1251 const Elf_Dyn *dyn_runpath; 1252 1253 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1254 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1255} 1256 1257/* 1258 * Process a shared object's program header. This is used only for the 1259 * main program, when the kernel has already loaded the main program 1260 * into memory before calling the dynamic linker. It creates and 1261 * returns an Obj_Entry structure. 1262 */ 1263static Obj_Entry * 1264digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1265{ 1266 Obj_Entry *obj; 1267 const Elf_Phdr *phlimit = phdr + phnum; 1268 const Elf_Phdr *ph; 1269 Elf_Addr note_start, note_end; 1270 int nsegs = 0; 1271 1272 obj = obj_new(); 1273 for (ph = phdr; ph < phlimit; ph++) { 1274 if (ph->p_type != PT_PHDR) 1275 continue; 1276 1277 obj->phdr = phdr; 1278 obj->phsize = ph->p_memsz; 1279 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1280 break; 1281 } 1282 1283 obj->stack_flags = PF_X | PF_R | PF_W; 1284 1285 for (ph = phdr; ph < phlimit; ph++) { 1286 switch (ph->p_type) { 1287 1288 case PT_INTERP: 1289 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1290 break; 1291 1292 case PT_LOAD: 1293 if (nsegs == 0) { /* First load segment */ 1294 obj->vaddrbase = trunc_page(ph->p_vaddr); 1295 obj->mapbase = obj->vaddrbase + obj->relocbase; 1296 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1297 obj->vaddrbase; 1298 } else { /* Last load segment */ 1299 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1300 obj->vaddrbase; 1301 } 1302 nsegs++; 1303 break; 1304 1305 case PT_DYNAMIC: 1306 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1307 break; 1308 1309 case PT_TLS: 1310 obj->tlsindex = 1; 1311 obj->tlssize = ph->p_memsz; 1312 obj->tlsalign = ph->p_align; 1313 obj->tlsinitsize = ph->p_filesz; 1314 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1315 break; 1316 1317 case PT_GNU_STACK: 1318 obj->stack_flags = ph->p_flags; 1319 break; 1320 1321 case PT_GNU_RELRO: 1322 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1323 obj->relro_size = round_page(ph->p_memsz); 1324 break; 1325 1326 case PT_NOTE: 1327 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1328 note_end = note_start + ph->p_filesz; 1329 digest_notes(obj, note_start, note_end); 1330 break; 1331 } 1332 } 1333 if (nsegs < 1) { 1334 _rtld_error("%s: too few PT_LOAD segments", path); 1335 return NULL; 1336 } 1337 1338 obj->entry = entry; 1339 return obj; 1340} 1341 1342void 1343digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1344{ 1345 const Elf_Note *note; 1346 const char *note_name; 1347 uintptr_t p; 1348 1349 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1350 note = (const Elf_Note *)((const char *)(note + 1) + 1351 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1352 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1353 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1354 note->n_descsz != sizeof(int32_t)) 1355 continue; 1356 if (note->n_type != ABI_NOTETYPE && 1357 note->n_type != CRT_NOINIT_NOTETYPE) 1358 continue; 1359 note_name = (const char *)(note + 1); 1360 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1361 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1362 continue; 1363 switch (note->n_type) { 1364 case ABI_NOTETYPE: 1365 /* FreeBSD osrel note */ 1366 p = (uintptr_t)(note + 1); 1367 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1368 obj->osrel = *(const int32_t *)(p); 1369 dbg("note osrel %d", obj->osrel); 1370 break; 1371 case CRT_NOINIT_NOTETYPE: 1372 /* FreeBSD 'crt does not call init' note */ 1373 obj->crt_no_init = true; 1374 dbg("note crt_no_init"); 1375 break; 1376 } 1377 } 1378} 1379 1380static Obj_Entry * 1381dlcheck(void *handle) 1382{ 1383 Obj_Entry *obj; 1384 1385 TAILQ_FOREACH(obj, &obj_list, next) { 1386 if (obj == (Obj_Entry *) handle) 1387 break; 1388 } 1389 1390 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1391 _rtld_error("Invalid shared object handle %p", handle); 1392 return NULL; 1393 } 1394 return obj; 1395} 1396 1397/* 1398 * If the given object is already in the donelist, return true. Otherwise 1399 * add the object to the list and return false. 1400 */ 1401static bool 1402donelist_check(DoneList *dlp, const Obj_Entry *obj) 1403{ 1404 unsigned int i; 1405 1406 for (i = 0; i < dlp->num_used; i++) 1407 if (dlp->objs[i] == obj) 1408 return true; 1409 /* 1410 * Our donelist allocation should always be sufficient. But if 1411 * our threads locking isn't working properly, more shared objects 1412 * could have been loaded since we allocated the list. That should 1413 * never happen, but we'll handle it properly just in case it does. 1414 */ 1415 if (dlp->num_used < dlp->num_alloc) 1416 dlp->objs[dlp->num_used++] = obj; 1417 return false; 1418} 1419 1420/* 1421 * Hash function for symbol table lookup. Don't even think about changing 1422 * this. It is specified by the System V ABI. 1423 */ 1424unsigned long 1425elf_hash(const char *name) 1426{ 1427 const unsigned char *p = (const unsigned char *) name; 1428 unsigned long h = 0; 1429 unsigned long g; 1430 1431 while (*p != '\0') { 1432 h = (h << 4) + *p++; 1433 if ((g = h & 0xf0000000) != 0) 1434 h ^= g >> 24; 1435 h &= ~g; 1436 } 1437 return h; 1438} 1439 1440/* 1441 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1442 * unsigned in case it's implemented with a wider type. 1443 */ 1444static uint32_t 1445gnu_hash(const char *s) 1446{ 1447 uint32_t h; 1448 unsigned char c; 1449 1450 h = 5381; 1451 for (c = *s; c != '\0'; c = *++s) 1452 h = h * 33 + c; 1453 return (h & 0xffffffff); 1454} 1455 1456/* 1457 * Find the library with the given name, and return its full pathname. 1458 * The returned string is dynamically allocated. Generates an error 1459 * message and returns NULL if the library cannot be found. 1460 * 1461 * If the second argument is non-NULL, then it refers to an already- 1462 * loaded shared object, whose library search path will be searched. 1463 * 1464 * The search order is: 1465 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1466 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1467 * LD_LIBRARY_PATH 1468 * DT_RUNPATH in the referencing file 1469 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1470 * from list) 1471 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1472 * 1473 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1474 */ 1475static char * 1476find_library(const char *xname, const Obj_Entry *refobj) 1477{ 1478 char *pathname; 1479 char *name; 1480 bool nodeflib, objgiven; 1481 1482 objgiven = refobj != NULL; 1483 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1484 if (xname[0] != '/' && !trust) { 1485 _rtld_error("Absolute pathname required for shared object \"%s\"", 1486 xname); 1487 return NULL; 1488 } 1489 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1490 __DECONST(char *, xname))); 1491 } 1492 1493 if (libmap_disable || !objgiven || 1494 (name = lm_find(refobj->path, xname)) == NULL) 1495 name = (char *)xname; 1496 1497 dbg(" Searching for \"%s\"", name); 1498 1499 /* 1500 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1501 * back to pre-conforming behaviour if user requested so with 1502 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1503 * nodeflib. 1504 */ 1505 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1506 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1507 (refobj != NULL && 1508 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1509 (pathname = search_library_path(name, gethints(false))) != NULL || 1510 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1511 return (pathname); 1512 } else { 1513 nodeflib = objgiven ? refobj->z_nodeflib : false; 1514 if ((objgiven && 1515 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1516 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1517 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1518 (pathname = search_library_path(name, ld_library_path)) != NULL || 1519 (objgiven && 1520 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1521 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1522 (objgiven && !nodeflib && 1523 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1524 return (pathname); 1525 } 1526 1527 if (objgiven && refobj->path != NULL) { 1528 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1529 name, basename(refobj->path)); 1530 } else { 1531 _rtld_error("Shared object \"%s\" not found", name); 1532 } 1533 return NULL; 1534} 1535 1536/* 1537 * Given a symbol number in a referencing object, find the corresponding 1538 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1539 * no definition was found. Returns a pointer to the Obj_Entry of the 1540 * defining object via the reference parameter DEFOBJ_OUT. 1541 */ 1542const Elf_Sym * 1543find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1544 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1545 RtldLockState *lockstate) 1546{ 1547 const Elf_Sym *ref; 1548 const Elf_Sym *def; 1549 const Obj_Entry *defobj; 1550 SymLook req; 1551 const char *name; 1552 int res; 1553 1554 /* 1555 * If we have already found this symbol, get the information from 1556 * the cache. 1557 */ 1558 if (symnum >= refobj->dynsymcount) 1559 return NULL; /* Bad object */ 1560 if (cache != NULL && cache[symnum].sym != NULL) { 1561 *defobj_out = cache[symnum].obj; 1562 return cache[symnum].sym; 1563 } 1564 1565 ref = refobj->symtab + symnum; 1566 name = refobj->strtab + ref->st_name; 1567 def = NULL; 1568 defobj = NULL; 1569 1570 /* 1571 * We don't have to do a full scale lookup if the symbol is local. 1572 * We know it will bind to the instance in this load module; to 1573 * which we already have a pointer (ie ref). By not doing a lookup, 1574 * we not only improve performance, but it also avoids unresolvable 1575 * symbols when local symbols are not in the hash table. This has 1576 * been seen with the ia64 toolchain. 1577 */ 1578 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1579 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1580 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1581 symnum); 1582 } 1583 symlook_init(&req, name); 1584 req.flags = flags; 1585 req.ventry = fetch_ventry(refobj, symnum); 1586 req.lockstate = lockstate; 1587 res = symlook_default(&req, refobj); 1588 if (res == 0) { 1589 def = req.sym_out; 1590 defobj = req.defobj_out; 1591 } 1592 } else { 1593 def = ref; 1594 defobj = refobj; 1595 } 1596 1597 /* 1598 * If we found no definition and the reference is weak, treat the 1599 * symbol as having the value zero. 1600 */ 1601 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1602 def = &sym_zero; 1603 defobj = obj_main; 1604 } 1605 1606 if (def != NULL) { 1607 *defobj_out = defobj; 1608 /* Record the information in the cache to avoid subsequent lookups. */ 1609 if (cache != NULL) { 1610 cache[symnum].sym = def; 1611 cache[symnum].obj = defobj; 1612 } 1613 } else { 1614 if (refobj != &obj_rtld) 1615 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1616 } 1617 return def; 1618} 1619 1620/* 1621 * Return the search path from the ldconfig hints file, reading it if 1622 * necessary. If nostdlib is true, then the default search paths are 1623 * not added to result. 1624 * 1625 * Returns NULL if there are problems with the hints file, 1626 * or if the search path there is empty. 1627 */ 1628static const char * 1629gethints(bool nostdlib) 1630{ 1631 static char *hints, *filtered_path; 1632 static struct elfhints_hdr hdr; 1633 struct fill_search_info_args sargs, hargs; 1634 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1635 struct dl_serpath *SLPpath, *hintpath; 1636 char *p; 1637 struct stat hint_stat; 1638 unsigned int SLPndx, hintndx, fndx, fcount; 1639 int fd; 1640 size_t flen; 1641 uint32_t dl; 1642 bool skip; 1643 1644 /* First call, read the hints file */ 1645 if (hints == NULL) { 1646 /* Keep from trying again in case the hints file is bad. */ 1647 hints = ""; 1648 1649 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1650 return (NULL); 1651 1652 /* 1653 * Check of hdr.dirlistlen value against type limit 1654 * intends to pacify static analyzers. Further 1655 * paranoia leads to checks that dirlist is fully 1656 * contained in the file range. 1657 */ 1658 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1659 hdr.magic != ELFHINTS_MAGIC || 1660 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1661 fstat(fd, &hint_stat) == -1) { 1662cleanup1: 1663 close(fd); 1664 hdr.dirlistlen = 0; 1665 return (NULL); 1666 } 1667 dl = hdr.strtab; 1668 if (dl + hdr.dirlist < dl) 1669 goto cleanup1; 1670 dl += hdr.dirlist; 1671 if (dl + hdr.dirlistlen < dl) 1672 goto cleanup1; 1673 dl += hdr.dirlistlen; 1674 if (dl > hint_stat.st_size) 1675 goto cleanup1; 1676 p = xmalloc(hdr.dirlistlen + 1); 1677 1678 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1679 read(fd, p, hdr.dirlistlen + 1) != 1680 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1681 free(p); 1682 goto cleanup1; 1683 } 1684 hints = p; 1685 close(fd); 1686 } 1687 1688 /* 1689 * If caller agreed to receive list which includes the default 1690 * paths, we are done. Otherwise, if we still did not 1691 * calculated filtered result, do it now. 1692 */ 1693 if (!nostdlib) 1694 return (hints[0] != '\0' ? hints : NULL); 1695 if (filtered_path != NULL) 1696 goto filt_ret; 1697 1698 /* 1699 * Obtain the list of all configured search paths, and the 1700 * list of the default paths. 1701 * 1702 * First estimate the size of the results. 1703 */ 1704 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1705 smeta.dls_cnt = 0; 1706 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1707 hmeta.dls_cnt = 0; 1708 1709 sargs.request = RTLD_DI_SERINFOSIZE; 1710 sargs.serinfo = &smeta; 1711 hargs.request = RTLD_DI_SERINFOSIZE; 1712 hargs.serinfo = &hmeta; 1713 1714 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1715 path_enumerate(hints, fill_search_info, &hargs); 1716 1717 SLPinfo = xmalloc(smeta.dls_size); 1718 hintinfo = xmalloc(hmeta.dls_size); 1719 1720 /* 1721 * Next fetch both sets of paths. 1722 */ 1723 sargs.request = RTLD_DI_SERINFO; 1724 sargs.serinfo = SLPinfo; 1725 sargs.serpath = &SLPinfo->dls_serpath[0]; 1726 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1727 1728 hargs.request = RTLD_DI_SERINFO; 1729 hargs.serinfo = hintinfo; 1730 hargs.serpath = &hintinfo->dls_serpath[0]; 1731 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1732 1733 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1734 path_enumerate(hints, fill_search_info, &hargs); 1735 1736 /* 1737 * Now calculate the difference between two sets, by excluding 1738 * standard paths from the full set. 1739 */ 1740 fndx = 0; 1741 fcount = 0; 1742 filtered_path = xmalloc(hdr.dirlistlen + 1); 1743 hintpath = &hintinfo->dls_serpath[0]; 1744 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1745 skip = false; 1746 SLPpath = &SLPinfo->dls_serpath[0]; 1747 /* 1748 * Check each standard path against current. 1749 */ 1750 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1751 /* matched, skip the path */ 1752 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1753 skip = true; 1754 break; 1755 } 1756 } 1757 if (skip) 1758 continue; 1759 /* 1760 * Not matched against any standard path, add the path 1761 * to result. Separate consequtive paths with ':'. 1762 */ 1763 if (fcount > 0) { 1764 filtered_path[fndx] = ':'; 1765 fndx++; 1766 } 1767 fcount++; 1768 flen = strlen(hintpath->dls_name); 1769 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1770 fndx += flen; 1771 } 1772 filtered_path[fndx] = '\0'; 1773 1774 free(SLPinfo); 1775 free(hintinfo); 1776 1777filt_ret: 1778 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1779} 1780 1781static void 1782init_dag(Obj_Entry *root) 1783{ 1784 const Needed_Entry *needed; 1785 const Objlist_Entry *elm; 1786 DoneList donelist; 1787 1788 if (root->dag_inited) 1789 return; 1790 donelist_init(&donelist); 1791 1792 /* Root object belongs to own DAG. */ 1793 objlist_push_tail(&root->dldags, root); 1794 objlist_push_tail(&root->dagmembers, root); 1795 donelist_check(&donelist, root); 1796 1797 /* 1798 * Add dependencies of root object to DAG in breadth order 1799 * by exploiting the fact that each new object get added 1800 * to the tail of the dagmembers list. 1801 */ 1802 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1803 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1804 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1805 continue; 1806 objlist_push_tail(&needed->obj->dldags, root); 1807 objlist_push_tail(&root->dagmembers, needed->obj); 1808 } 1809 } 1810 root->dag_inited = true; 1811} 1812 1813Obj_Entry * 1814globallist_curr(const Obj_Entry *obj) 1815{ 1816 1817 for (;;) { 1818 if (obj == NULL) 1819 return (NULL); 1820 if (!obj->marker) 1821 return (__DECONST(Obj_Entry *, obj)); 1822 obj = TAILQ_PREV(obj, obj_entry_q, next); 1823 } 1824} 1825 1826Obj_Entry * 1827globallist_next(const Obj_Entry *obj) 1828{ 1829 1830 for (;;) { 1831 obj = TAILQ_NEXT(obj, next); 1832 if (obj == NULL) 1833 return (NULL); 1834 if (!obj->marker) 1835 return (__DECONST(Obj_Entry *, obj)); 1836 } 1837} 1838 1839static void 1840process_z(Obj_Entry *root) 1841{ 1842 const Objlist_Entry *elm; 1843 Obj_Entry *obj; 1844 1845 /* 1846 * Walk over object DAG and process every dependent object 1847 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1848 * to grow their own DAG. 1849 * 1850 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1851 * symlook_global() to work. 1852 * 1853 * For DF_1_NODELETE, the DAG should have its reference upped. 1854 */ 1855 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1856 obj = elm->obj; 1857 if (obj == NULL) 1858 continue; 1859 if (obj->z_nodelete && !obj->ref_nodel) { 1860 dbg("obj %s -z nodelete", obj->path); 1861 init_dag(obj); 1862 ref_dag(obj); 1863 obj->ref_nodel = true; 1864 } 1865 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1866 dbg("obj %s -z global", obj->path); 1867 objlist_push_tail(&list_global, obj); 1868 init_dag(obj); 1869 } 1870 } 1871} 1872/* 1873 * Initialize the dynamic linker. The argument is the address at which 1874 * the dynamic linker has been mapped into memory. The primary task of 1875 * this function is to relocate the dynamic linker. 1876 */ 1877static void 1878init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1879{ 1880 Obj_Entry objtmp; /* Temporary rtld object */ 1881 const Elf_Ehdr *ehdr; 1882 const Elf_Dyn *dyn_rpath; 1883 const Elf_Dyn *dyn_soname; 1884 const Elf_Dyn *dyn_runpath; 1885 1886#ifdef RTLD_INIT_PAGESIZES_EARLY 1887 /* The page size is required by the dynamic memory allocator. */ 1888 init_pagesizes(aux_info); 1889#endif 1890 1891 /* 1892 * Conjure up an Obj_Entry structure for the dynamic linker. 1893 * 1894 * The "path" member can't be initialized yet because string constants 1895 * cannot yet be accessed. Below we will set it correctly. 1896 */ 1897 memset(&objtmp, 0, sizeof(objtmp)); 1898 objtmp.path = NULL; 1899 objtmp.rtld = true; 1900 objtmp.mapbase = mapbase; 1901#ifdef PIC 1902 objtmp.relocbase = mapbase; 1903#endif 1904 if (RTLD_IS_DYNAMIC()) { 1905 objtmp.dynamic = rtld_dynamic(&objtmp); 1906 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1907 assert(objtmp.needed == NULL); 1908#if !defined(__mips__) 1909 /* MIPS has a bogus DT_TEXTREL. */ 1910 assert(!objtmp.textrel); 1911#endif 1912 1913 /* 1914 * Temporarily put the dynamic linker entry into the object list, so 1915 * that symbols can be found. 1916 */ 1917 1918 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1919 } 1920 ehdr = (Elf_Ehdr *)mapbase; 1921 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1922 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1923 1924 /* Initialize the object list. */ 1925 TAILQ_INIT(&obj_list); 1926 1927 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1928 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1929 1930#ifndef RTLD_INIT_PAGESIZES_EARLY 1931 /* The page size is required by the dynamic memory allocator. */ 1932 init_pagesizes(aux_info); 1933#endif 1934 1935 if (aux_info[AT_OSRELDATE] != NULL) 1936 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1937 1938 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1939 1940 /* Replace the path with a dynamically allocated copy. */ 1941 obj_rtld.path = xstrdup(PATH_RTLD); 1942 1943 r_debug.r_brk = r_debug_state; 1944 r_debug.r_state = RT_CONSISTENT; 1945} 1946 1947/* 1948 * Retrieve the array of supported page sizes. The kernel provides the page 1949 * sizes in increasing order. 1950 */ 1951static void 1952init_pagesizes(Elf_Auxinfo **aux_info) 1953{ 1954 static size_t psa[MAXPAGESIZES]; 1955 int mib[2]; 1956 size_t len, size; 1957 1958 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1959 NULL) { 1960 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1961 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1962 } else { 1963 len = 2; 1964 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1965 size = sizeof(psa); 1966 else { 1967 /* As a fallback, retrieve the base page size. */ 1968 size = sizeof(psa[0]); 1969 if (aux_info[AT_PAGESZ] != NULL) { 1970 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1971 goto psa_filled; 1972 } else { 1973 mib[0] = CTL_HW; 1974 mib[1] = HW_PAGESIZE; 1975 len = 2; 1976 } 1977 } 1978 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1979 _rtld_error("sysctl for hw.pagesize(s) failed"); 1980 rtld_die(); 1981 } 1982psa_filled: 1983 pagesizes = psa; 1984 } 1985 npagesizes = size / sizeof(pagesizes[0]); 1986 /* Discard any invalid entries at the end of the array. */ 1987 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1988 npagesizes--; 1989} 1990 1991/* 1992 * Add the init functions from a needed object list (and its recursive 1993 * needed objects) to "list". This is not used directly; it is a helper 1994 * function for initlist_add_objects(). The write lock must be held 1995 * when this function is called. 1996 */ 1997static void 1998initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1999{ 2000 /* Recursively process the successor needed objects. */ 2001 if (needed->next != NULL) 2002 initlist_add_neededs(needed->next, list); 2003 2004 /* Process the current needed object. */ 2005 if (needed->obj != NULL) 2006 initlist_add_objects(needed->obj, needed->obj, list); 2007} 2008 2009/* 2010 * Scan all of the DAGs rooted in the range of objects from "obj" to 2011 * "tail" and add their init functions to "list". This recurses over 2012 * the DAGs and ensure the proper init ordering such that each object's 2013 * needed libraries are initialized before the object itself. At the 2014 * same time, this function adds the objects to the global finalization 2015 * list "list_fini" in the opposite order. The write lock must be 2016 * held when this function is called. 2017 */ 2018static void 2019initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2020{ 2021 Obj_Entry *nobj; 2022 2023 if (obj->init_scanned || obj->init_done) 2024 return; 2025 obj->init_scanned = true; 2026 2027 /* Recursively process the successor objects. */ 2028 nobj = globallist_next(obj); 2029 if (nobj != NULL && obj != tail) 2030 initlist_add_objects(nobj, tail, list); 2031 2032 /* Recursively process the needed objects. */ 2033 if (obj->needed != NULL) 2034 initlist_add_neededs(obj->needed, list); 2035 if (obj->needed_filtees != NULL) 2036 initlist_add_neededs(obj->needed_filtees, list); 2037 if (obj->needed_aux_filtees != NULL) 2038 initlist_add_neededs(obj->needed_aux_filtees, list); 2039 2040 /* Add the object to the init list. */ 2041 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2042 obj->init_array != (Elf_Addr)NULL) 2043 objlist_push_tail(list, obj); 2044 2045 /* Add the object to the global fini list in the reverse order. */ 2046 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2047 && !obj->on_fini_list) { 2048 objlist_push_head(&list_fini, obj); 2049 obj->on_fini_list = true; 2050 } 2051} 2052 2053#ifndef FPTR_TARGET 2054#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2055#endif 2056 2057static void 2058free_needed_filtees(Needed_Entry *n) 2059{ 2060 Needed_Entry *needed, *needed1; 2061 2062 for (needed = n; needed != NULL; needed = needed->next) { 2063 if (needed->obj != NULL) { 2064 dlclose(needed->obj); 2065 needed->obj = NULL; 2066 } 2067 } 2068 for (needed = n; needed != NULL; needed = needed1) { 2069 needed1 = needed->next; 2070 free(needed); 2071 } 2072} 2073 2074static void 2075unload_filtees(Obj_Entry *obj) 2076{ 2077 2078 free_needed_filtees(obj->needed_filtees); 2079 obj->needed_filtees = NULL; 2080 free_needed_filtees(obj->needed_aux_filtees); 2081 obj->needed_aux_filtees = NULL; 2082 obj->filtees_loaded = false; 2083} 2084 2085static void 2086load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2087 RtldLockState *lockstate) 2088{ 2089 2090 for (; needed != NULL; needed = needed->next) { 2091 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2092 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2093 RTLD_LOCAL, lockstate); 2094 } 2095} 2096 2097static void 2098load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2099{ 2100 2101 lock_restart_for_upgrade(lockstate); 2102 if (!obj->filtees_loaded) { 2103 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2104 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2105 obj->filtees_loaded = true; 2106 } 2107} 2108 2109static int 2110process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2111{ 2112 Obj_Entry *obj1; 2113 2114 for (; needed != NULL; needed = needed->next) { 2115 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2116 flags & ~RTLD_LO_NOLOAD); 2117 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2118 return (-1); 2119 } 2120 return (0); 2121} 2122 2123/* 2124 * Given a shared object, traverse its list of needed objects, and load 2125 * each of them. Returns 0 on success. Generates an error message and 2126 * returns -1 on failure. 2127 */ 2128static int 2129load_needed_objects(Obj_Entry *first, int flags) 2130{ 2131 Obj_Entry *obj; 2132 2133 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2134 if (obj->marker) 2135 continue; 2136 if (process_needed(obj, obj->needed, flags) == -1) 2137 return (-1); 2138 } 2139 return (0); 2140} 2141 2142static int 2143load_preload_objects(void) 2144{ 2145 char *p = ld_preload; 2146 Obj_Entry *obj; 2147 static const char delim[] = " \t:;"; 2148 2149 if (p == NULL) 2150 return 0; 2151 2152 p += strspn(p, delim); 2153 while (*p != '\0') { 2154 size_t len = strcspn(p, delim); 2155 char savech; 2156 2157 savech = p[len]; 2158 p[len] = '\0'; 2159 obj = load_object(p, -1, NULL, 0); 2160 if (obj == NULL) 2161 return -1; /* XXX - cleanup */ 2162 obj->z_interpose = true; 2163 p[len] = savech; 2164 p += len; 2165 p += strspn(p, delim); 2166 } 2167 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2168 return 0; 2169} 2170 2171static const char * 2172printable_path(const char *path) 2173{ 2174 2175 return (path == NULL ? "<unknown>" : path); 2176} 2177 2178/* 2179 * Load a shared object into memory, if it is not already loaded. The 2180 * object may be specified by name or by user-supplied file descriptor 2181 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2182 * duplicate is. 2183 * 2184 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2185 * on failure. 2186 */ 2187static Obj_Entry * 2188load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2189{ 2190 Obj_Entry *obj; 2191 int fd; 2192 struct stat sb; 2193 char *path; 2194 2195 if (name != NULL) { 2196 TAILQ_FOREACH(obj, &obj_list, next) { 2197 if (obj->marker) 2198 continue; 2199 if (object_match_name(obj, name)) 2200 return (obj); 2201 } 2202 2203 path = find_library(name, refobj); 2204 if (path == NULL) 2205 return (NULL); 2206 } else 2207 path = NULL; 2208 2209 /* 2210 * If we didn't find a match by pathname, or the name is not 2211 * supplied, open the file and check again by device and inode. 2212 * This avoids false mismatches caused by multiple links or ".." 2213 * in pathnames. 2214 * 2215 * To avoid a race, we open the file and use fstat() rather than 2216 * using stat(). 2217 */ 2218 fd = -1; 2219 if (fd_u == -1) { 2220 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2221 _rtld_error("Cannot open \"%s\"", path); 2222 free(path); 2223 return (NULL); 2224 } 2225 } else { 2226 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2227 if (fd == -1) { 2228 _rtld_error("Cannot dup fd"); 2229 free(path); 2230 return (NULL); 2231 } 2232 } 2233 if (fstat(fd, &sb) == -1) { 2234 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2235 close(fd); 2236 free(path); 2237 return NULL; 2238 } 2239 TAILQ_FOREACH(obj, &obj_list, next) { 2240 if (obj->marker) 2241 continue; 2242 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2243 break; 2244 } 2245 if (obj != NULL && name != NULL) { 2246 object_add_name(obj, name); 2247 free(path); 2248 close(fd); 2249 return obj; 2250 } 2251 if (flags & RTLD_LO_NOLOAD) { 2252 free(path); 2253 close(fd); 2254 return (NULL); 2255 } 2256 2257 /* First use of this object, so we must map it in */ 2258 obj = do_load_object(fd, name, path, &sb, flags); 2259 if (obj == NULL) 2260 free(path); 2261 close(fd); 2262 2263 return obj; 2264} 2265 2266static Obj_Entry * 2267do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2268 int flags) 2269{ 2270 Obj_Entry *obj; 2271 struct statfs fs; 2272 2273 /* 2274 * but first, make sure that environment variables haven't been 2275 * used to circumvent the noexec flag on a filesystem. 2276 */ 2277 if (dangerous_ld_env) { 2278 if (fstatfs(fd, &fs) != 0) { 2279 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2280 return NULL; 2281 } 2282 if (fs.f_flags & MNT_NOEXEC) { 2283 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2284 return NULL; 2285 } 2286 } 2287 dbg("loading \"%s\"", printable_path(path)); 2288 obj = map_object(fd, printable_path(path), sbp); 2289 if (obj == NULL) 2290 return NULL; 2291 2292 /* 2293 * If DT_SONAME is present in the object, digest_dynamic2 already 2294 * added it to the object names. 2295 */ 2296 if (name != NULL) 2297 object_add_name(obj, name); 2298 obj->path = path; 2299 digest_dynamic(obj, 0); 2300 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2301 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2302 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2303 RTLD_LO_DLOPEN) { 2304 dbg("refusing to load non-loadable \"%s\"", obj->path); 2305 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2306 munmap(obj->mapbase, obj->mapsize); 2307 obj_free(obj); 2308 return (NULL); 2309 } 2310 2311 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2312 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2313 obj_count++; 2314 obj_loads++; 2315 linkmap_add(obj); /* for GDB & dlinfo() */ 2316 max_stack_flags |= obj->stack_flags; 2317 2318 dbg(" %p .. %p: %s", obj->mapbase, 2319 obj->mapbase + obj->mapsize - 1, obj->path); 2320 if (obj->textrel) 2321 dbg(" WARNING: %s has impure text", obj->path); 2322 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2323 obj->path); 2324 2325 return obj; 2326} 2327 2328static Obj_Entry * 2329obj_from_addr(const void *addr) 2330{ 2331 Obj_Entry *obj; 2332 2333 TAILQ_FOREACH(obj, &obj_list, next) { 2334 if (obj->marker) 2335 continue; 2336 if (addr < (void *) obj->mapbase) 2337 continue; 2338 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2339 return obj; 2340 } 2341 return NULL; 2342} 2343 2344static void 2345preinit_main(void) 2346{ 2347 Elf_Addr *preinit_addr; 2348 int index; 2349 2350 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2351 if (preinit_addr == NULL) 2352 return; 2353 2354 for (index = 0; index < obj_main->preinit_array_num; index++) { 2355 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2356 dbg("calling preinit function for %s at %p", obj_main->path, 2357 (void *)preinit_addr[index]); 2358 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2359 0, 0, obj_main->path); 2360 call_init_pointer(obj_main, preinit_addr[index]); 2361 } 2362 } 2363} 2364 2365/* 2366 * Call the finalization functions for each of the objects in "list" 2367 * belonging to the DAG of "root" and referenced once. If NULL "root" 2368 * is specified, every finalization function will be called regardless 2369 * of the reference count and the list elements won't be freed. All of 2370 * the objects are expected to have non-NULL fini functions. 2371 */ 2372static void 2373objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2374{ 2375 Objlist_Entry *elm; 2376 char *saved_msg; 2377 Elf_Addr *fini_addr; 2378 int index; 2379 2380 assert(root == NULL || root->refcount == 1); 2381 2382 /* 2383 * Preserve the current error message since a fini function might 2384 * call into the dynamic linker and overwrite it. 2385 */ 2386 saved_msg = errmsg_save(); 2387 do { 2388 STAILQ_FOREACH(elm, list, link) { 2389 if (root != NULL && (elm->obj->refcount != 1 || 2390 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2391 continue; 2392 /* Remove object from fini list to prevent recursive invocation. */ 2393 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2394 /* 2395 * XXX: If a dlopen() call references an object while the 2396 * fini function is in progress, we might end up trying to 2397 * unload the referenced object in dlclose() or the object 2398 * won't be unloaded although its fini function has been 2399 * called. 2400 */ 2401 lock_release(rtld_bind_lock, lockstate); 2402 2403 /* 2404 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2405 * When this happens, DT_FINI_ARRAY is processed first. 2406 */ 2407 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2408 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2409 for (index = elm->obj->fini_array_num - 1; index >= 0; 2410 index--) { 2411 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2412 dbg("calling fini function for %s at %p", 2413 elm->obj->path, (void *)fini_addr[index]); 2414 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2415 (void *)fini_addr[index], 0, 0, elm->obj->path); 2416 call_initfini_pointer(elm->obj, fini_addr[index]); 2417 } 2418 } 2419 } 2420 if (elm->obj->fini != (Elf_Addr)NULL) { 2421 dbg("calling fini function for %s at %p", elm->obj->path, 2422 (void *)elm->obj->fini); 2423 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2424 0, 0, elm->obj->path); 2425 call_initfini_pointer(elm->obj, elm->obj->fini); 2426 } 2427 wlock_acquire(rtld_bind_lock, lockstate); 2428 /* No need to free anything if process is going down. */ 2429 if (root != NULL) 2430 free(elm); 2431 /* 2432 * We must restart the list traversal after every fini call 2433 * because a dlclose() call from the fini function or from 2434 * another thread might have modified the reference counts. 2435 */ 2436 break; 2437 } 2438 } while (elm != NULL); 2439 errmsg_restore(saved_msg); 2440} 2441 2442/* 2443 * Call the initialization functions for each of the objects in 2444 * "list". All of the objects are expected to have non-NULL init 2445 * functions. 2446 */ 2447static void 2448objlist_call_init(Objlist *list, RtldLockState *lockstate) 2449{ 2450 Objlist_Entry *elm; 2451 Obj_Entry *obj; 2452 char *saved_msg; 2453 Elf_Addr *init_addr; 2454 int index; 2455 2456 /* 2457 * Clean init_scanned flag so that objects can be rechecked and 2458 * possibly initialized earlier if any of vectors called below 2459 * cause the change by using dlopen. 2460 */ 2461 TAILQ_FOREACH(obj, &obj_list, next) { 2462 if (obj->marker) 2463 continue; 2464 obj->init_scanned = false; 2465 } 2466 2467 /* 2468 * Preserve the current error message since an init function might 2469 * call into the dynamic linker and overwrite it. 2470 */ 2471 saved_msg = errmsg_save(); 2472 STAILQ_FOREACH(elm, list, link) { 2473 if (elm->obj->init_done) /* Initialized early. */ 2474 continue; 2475 /* 2476 * Race: other thread might try to use this object before current 2477 * one completes the initialization. Not much can be done here 2478 * without better locking. 2479 */ 2480 elm->obj->init_done = true; 2481 lock_release(rtld_bind_lock, lockstate); 2482 2483 /* 2484 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2485 * When this happens, DT_INIT is processed first. 2486 */ 2487 if (elm->obj->init != (Elf_Addr)NULL) { 2488 dbg("calling init function for %s at %p", elm->obj->path, 2489 (void *)elm->obj->init); 2490 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2491 0, 0, elm->obj->path); 2492 call_initfini_pointer(elm->obj, elm->obj->init); 2493 } 2494 init_addr = (Elf_Addr *)elm->obj->init_array; 2495 if (init_addr != NULL) { 2496 for (index = 0; index < elm->obj->init_array_num; index++) { 2497 if (init_addr[index] != 0 && init_addr[index] != 1) { 2498 dbg("calling init function for %s at %p", elm->obj->path, 2499 (void *)init_addr[index]); 2500 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2501 (void *)init_addr[index], 0, 0, elm->obj->path); 2502 call_init_pointer(elm->obj, init_addr[index]); 2503 } 2504 } 2505 } 2506 wlock_acquire(rtld_bind_lock, lockstate); 2507 } 2508 errmsg_restore(saved_msg); 2509} 2510 2511static void 2512objlist_clear(Objlist *list) 2513{ 2514 Objlist_Entry *elm; 2515 2516 while (!STAILQ_EMPTY(list)) { 2517 elm = STAILQ_FIRST(list); 2518 STAILQ_REMOVE_HEAD(list, link); 2519 free(elm); 2520 } 2521} 2522 2523static Objlist_Entry * 2524objlist_find(Objlist *list, const Obj_Entry *obj) 2525{ 2526 Objlist_Entry *elm; 2527 2528 STAILQ_FOREACH(elm, list, link) 2529 if (elm->obj == obj) 2530 return elm; 2531 return NULL; 2532} 2533 2534static void 2535objlist_init(Objlist *list) 2536{ 2537 STAILQ_INIT(list); 2538} 2539 2540static void 2541objlist_push_head(Objlist *list, Obj_Entry *obj) 2542{ 2543 Objlist_Entry *elm; 2544 2545 elm = NEW(Objlist_Entry); 2546 elm->obj = obj; 2547 STAILQ_INSERT_HEAD(list, elm, link); 2548} 2549 2550static void 2551objlist_push_tail(Objlist *list, Obj_Entry *obj) 2552{ 2553 Objlist_Entry *elm; 2554 2555 elm = NEW(Objlist_Entry); 2556 elm->obj = obj; 2557 STAILQ_INSERT_TAIL(list, elm, link); 2558} 2559 2560static void 2561objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2562{ 2563 Objlist_Entry *elm, *listelm; 2564 2565 STAILQ_FOREACH(listelm, list, link) { 2566 if (listelm->obj == listobj) 2567 break; 2568 } 2569 elm = NEW(Objlist_Entry); 2570 elm->obj = obj; 2571 if (listelm != NULL) 2572 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2573 else 2574 STAILQ_INSERT_TAIL(list, elm, link); 2575} 2576 2577static void 2578objlist_remove(Objlist *list, Obj_Entry *obj) 2579{ 2580 Objlist_Entry *elm; 2581 2582 if ((elm = objlist_find(list, obj)) != NULL) { 2583 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2584 free(elm); 2585 } 2586} 2587 2588/* 2589 * Relocate dag rooted in the specified object. 2590 * Returns 0 on success, or -1 on failure. 2591 */ 2592 2593static int 2594relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2595 int flags, RtldLockState *lockstate) 2596{ 2597 Objlist_Entry *elm; 2598 int error; 2599 2600 error = 0; 2601 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2602 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2603 lockstate); 2604 if (error == -1) 2605 break; 2606 } 2607 return (error); 2608} 2609 2610/* 2611 * Prepare for, or clean after, relocating an object marked with 2612 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2613 * segments are remapped read-write. After relocations are done, the 2614 * segment's permissions are returned back to the modes specified in 2615 * the phdrs. If any relocation happened, or always for wired 2616 * program, COW is triggered. 2617 */ 2618static int 2619reloc_textrel_prot(Obj_Entry *obj, bool before) 2620{ 2621 const Elf_Phdr *ph; 2622 void *base; 2623 size_t l, sz; 2624 int prot; 2625 2626 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2627 l--, ph++) { 2628 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2629 continue; 2630 base = obj->relocbase + trunc_page(ph->p_vaddr); 2631 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2632 trunc_page(ph->p_vaddr); 2633 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2634 if (mprotect(base, sz, prot) == -1) { 2635 _rtld_error("%s: Cannot write-%sable text segment: %s", 2636 obj->path, before ? "en" : "dis", 2637 rtld_strerror(errno)); 2638 return (-1); 2639 } 2640 } 2641 return (0); 2642} 2643 2644/* 2645 * Relocate single object. 2646 * Returns 0 on success, or -1 on failure. 2647 */ 2648static int 2649relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2650 int flags, RtldLockState *lockstate) 2651{ 2652 2653 if (obj->relocated) 2654 return (0); 2655 obj->relocated = true; 2656 if (obj != rtldobj) 2657 dbg("relocating \"%s\"", obj->path); 2658 2659 if (obj->symtab == NULL || obj->strtab == NULL || 2660 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2661 _rtld_error("%s: Shared object has no run-time symbol table", 2662 obj->path); 2663 return (-1); 2664 } 2665 2666 /* There are relocations to the write-protected text segment. */ 2667 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2668 return (-1); 2669 2670 /* Process the non-PLT non-IFUNC relocations. */ 2671 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2672 return (-1); 2673 2674 /* Re-protected the text segment. */ 2675 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2676 return (-1); 2677 2678 /* Set the special PLT or GOT entries. */ 2679 init_pltgot(obj); 2680 2681 /* Process the PLT relocations. */ 2682 if (reloc_plt(obj) == -1) 2683 return (-1); 2684 /* Relocate the jump slots if we are doing immediate binding. */ 2685 if (obj->bind_now || bind_now) 2686 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2687 return (-1); 2688 2689 /* 2690 * Process the non-PLT IFUNC relocations. The relocations are 2691 * processed in two phases, because IFUNC resolvers may 2692 * reference other symbols, which must be readily processed 2693 * before resolvers are called. 2694 */ 2695 if (obj->non_plt_gnu_ifunc && 2696 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2697 return (-1); 2698 2699 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2700 return (-1); 2701 2702 /* 2703 * Set up the magic number and version in the Obj_Entry. These 2704 * were checked in the crt1.o from the original ElfKit, so we 2705 * set them for backward compatibility. 2706 */ 2707 obj->magic = RTLD_MAGIC; 2708 obj->version = RTLD_VERSION; 2709 2710 return (0); 2711} 2712 2713/* 2714 * Relocate newly-loaded shared objects. The argument is a pointer to 2715 * the Obj_Entry for the first such object. All objects from the first 2716 * to the end of the list of objects are relocated. Returns 0 on success, 2717 * or -1 on failure. 2718 */ 2719static int 2720relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2721 int flags, RtldLockState *lockstate) 2722{ 2723 Obj_Entry *obj; 2724 int error; 2725 2726 for (error = 0, obj = first; obj != NULL; 2727 obj = TAILQ_NEXT(obj, next)) { 2728 if (obj->marker) 2729 continue; 2730 error = relocate_object(obj, bind_now, rtldobj, flags, 2731 lockstate); 2732 if (error == -1) 2733 break; 2734 } 2735 return (error); 2736} 2737 2738/* 2739 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2740 * referencing STT_GNU_IFUNC symbols is postponed till the other 2741 * relocations are done. The indirect functions specified as 2742 * ifunc are allowed to call other symbols, so we need to have 2743 * objects relocated before asking for resolution from indirects. 2744 * 2745 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2746 * instead of the usual lazy handling of PLT slots. It is 2747 * consistent with how GNU does it. 2748 */ 2749static int 2750resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2751 RtldLockState *lockstate) 2752{ 2753 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2754 return (-1); 2755 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2756 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2757 return (-1); 2758 return (0); 2759} 2760 2761static int 2762resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2763 RtldLockState *lockstate) 2764{ 2765 Obj_Entry *obj; 2766 2767 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2768 if (obj->marker) 2769 continue; 2770 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2771 return (-1); 2772 } 2773 return (0); 2774} 2775 2776static int 2777initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2778 RtldLockState *lockstate) 2779{ 2780 Objlist_Entry *elm; 2781 2782 STAILQ_FOREACH(elm, list, link) { 2783 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2784 lockstate) == -1) 2785 return (-1); 2786 } 2787 return (0); 2788} 2789 2790/* 2791 * Cleanup procedure. It will be called (by the atexit mechanism) just 2792 * before the process exits. 2793 */ 2794static void 2795rtld_exit(void) 2796{ 2797 RtldLockState lockstate; 2798 2799 wlock_acquire(rtld_bind_lock, &lockstate); 2800 dbg("rtld_exit()"); 2801 objlist_call_fini(&list_fini, NULL, &lockstate); 2802 /* No need to remove the items from the list, since we are exiting. */ 2803 if (!libmap_disable) 2804 lm_fini(); 2805 lock_release(rtld_bind_lock, &lockstate); 2806} 2807 2808/* 2809 * Iterate over a search path, translate each element, and invoke the 2810 * callback on the result. 2811 */ 2812static void * 2813path_enumerate(const char *path, path_enum_proc callback, void *arg) 2814{ 2815 const char *trans; 2816 if (path == NULL) 2817 return (NULL); 2818 2819 path += strspn(path, ":;"); 2820 while (*path != '\0') { 2821 size_t len; 2822 char *res; 2823 2824 len = strcspn(path, ":;"); 2825 trans = lm_findn(NULL, path, len); 2826 if (trans) 2827 res = callback(trans, strlen(trans), arg); 2828 else 2829 res = callback(path, len, arg); 2830 2831 if (res != NULL) 2832 return (res); 2833 2834 path += len; 2835 path += strspn(path, ":;"); 2836 } 2837 2838 return (NULL); 2839} 2840 2841struct try_library_args { 2842 const char *name; 2843 size_t namelen; 2844 char *buffer; 2845 size_t buflen; 2846}; 2847 2848static void * 2849try_library_path(const char *dir, size_t dirlen, void *param) 2850{ 2851 struct try_library_args *arg; 2852 2853 arg = param; 2854 if (*dir == '/' || trust) { 2855 char *pathname; 2856 2857 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2858 return (NULL); 2859 2860 pathname = arg->buffer; 2861 strncpy(pathname, dir, dirlen); 2862 pathname[dirlen] = '/'; 2863 strcpy(pathname + dirlen + 1, arg->name); 2864 2865 dbg(" Trying \"%s\"", pathname); 2866 if (access(pathname, F_OK) == 0) { /* We found it */ 2867 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2868 strcpy(pathname, arg->buffer); 2869 return (pathname); 2870 } 2871 } 2872 return (NULL); 2873} 2874 2875static char * 2876search_library_path(const char *name, const char *path) 2877{ 2878 char *p; 2879 struct try_library_args arg; 2880 2881 if (path == NULL) 2882 return NULL; 2883 2884 arg.name = name; 2885 arg.namelen = strlen(name); 2886 arg.buffer = xmalloc(PATH_MAX); 2887 arg.buflen = PATH_MAX; 2888 2889 p = path_enumerate(path, try_library_path, &arg); 2890 2891 free(arg.buffer); 2892 2893 return (p); 2894} 2895 2896int 2897dlclose(void *handle) 2898{ 2899 Obj_Entry *root; 2900 RtldLockState lockstate; 2901 2902 wlock_acquire(rtld_bind_lock, &lockstate); 2903 root = dlcheck(handle); 2904 if (root == NULL) { 2905 lock_release(rtld_bind_lock, &lockstate); 2906 return -1; 2907 } 2908 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2909 root->path); 2910 2911 /* Unreference the object and its dependencies. */ 2912 root->dl_refcount--; 2913 2914 if (root->refcount == 1) { 2915 /* 2916 * The object will be no longer referenced, so we must unload it. 2917 * First, call the fini functions. 2918 */ 2919 objlist_call_fini(&list_fini, root, &lockstate); 2920 2921 unref_dag(root); 2922 2923 /* Finish cleaning up the newly-unreferenced objects. */ 2924 GDB_STATE(RT_DELETE,&root->linkmap); 2925 unload_object(root); 2926 GDB_STATE(RT_CONSISTENT,NULL); 2927 } else 2928 unref_dag(root); 2929 2930 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2931 lock_release(rtld_bind_lock, &lockstate); 2932 return 0; 2933} 2934 2935char * 2936dlerror(void) 2937{ 2938 char *msg = error_message; 2939 error_message = NULL; 2940 return msg; 2941} 2942 2943/* 2944 * This function is deprecated and has no effect. 2945 */ 2946void 2947dllockinit(void *context, 2948 void *(*lock_create)(void *context), 2949 void (*rlock_acquire)(void *lock), 2950 void (*wlock_acquire)(void *lock), 2951 void (*lock_release)(void *lock), 2952 void (*lock_destroy)(void *lock), 2953 void (*context_destroy)(void *context)) 2954{ 2955 static void *cur_context; 2956 static void (*cur_context_destroy)(void *); 2957 2958 /* Just destroy the context from the previous call, if necessary. */ 2959 if (cur_context_destroy != NULL) 2960 cur_context_destroy(cur_context); 2961 cur_context = context; 2962 cur_context_destroy = context_destroy; 2963} 2964 2965void * 2966dlopen(const char *name, int mode) 2967{ 2968 2969 return (rtld_dlopen(name, -1, mode)); 2970} 2971 2972void * 2973fdlopen(int fd, int mode) 2974{ 2975 2976 return (rtld_dlopen(NULL, fd, mode)); 2977} 2978 2979static void * 2980rtld_dlopen(const char *name, int fd, int mode) 2981{ 2982 RtldLockState lockstate; 2983 int lo_flags; 2984 2985 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2986 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2987 if (ld_tracing != NULL) { 2988 rlock_acquire(rtld_bind_lock, &lockstate); 2989 if (sigsetjmp(lockstate.env, 0) != 0) 2990 lock_upgrade(rtld_bind_lock, &lockstate); 2991 environ = (char **)*get_program_var_addr("environ", &lockstate); 2992 lock_release(rtld_bind_lock, &lockstate); 2993 } 2994 lo_flags = RTLD_LO_DLOPEN; 2995 if (mode & RTLD_NODELETE) 2996 lo_flags |= RTLD_LO_NODELETE; 2997 if (mode & RTLD_NOLOAD) 2998 lo_flags |= RTLD_LO_NOLOAD; 2999 if (ld_tracing != NULL) 3000 lo_flags |= RTLD_LO_TRACE; 3001 3002 return (dlopen_object(name, fd, obj_main, lo_flags, 3003 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3004} 3005 3006static void 3007dlopen_cleanup(Obj_Entry *obj) 3008{ 3009 3010 obj->dl_refcount--; 3011 unref_dag(obj); 3012 if (obj->refcount == 0) 3013 unload_object(obj); 3014} 3015 3016static Obj_Entry * 3017dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3018 int mode, RtldLockState *lockstate) 3019{ 3020 Obj_Entry *old_obj_tail; 3021 Obj_Entry *obj; 3022 Objlist initlist; 3023 RtldLockState mlockstate; 3024 int result; 3025 3026 objlist_init(&initlist); 3027 3028 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3029 wlock_acquire(rtld_bind_lock, &mlockstate); 3030 lockstate = &mlockstate; 3031 } 3032 GDB_STATE(RT_ADD,NULL); 3033 3034 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3035 obj = NULL; 3036 if (name == NULL && fd == -1) { 3037 obj = obj_main; 3038 obj->refcount++; 3039 } else { 3040 obj = load_object(name, fd, refobj, lo_flags); 3041 } 3042 3043 if (obj) { 3044 obj->dl_refcount++; 3045 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3046 objlist_push_tail(&list_global, obj); 3047 if (globallist_next(old_obj_tail) != NULL) { 3048 /* We loaded something new. */ 3049 assert(globallist_next(old_obj_tail) == obj); 3050 result = load_needed_objects(obj, 3051 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3052 init_dag(obj); 3053 ref_dag(obj); 3054 if (result != -1) 3055 result = rtld_verify_versions(&obj->dagmembers); 3056 if (result != -1 && ld_tracing) 3057 goto trace; 3058 if (result == -1 || relocate_object_dag(obj, 3059 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3060 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3061 lockstate) == -1) { 3062 dlopen_cleanup(obj); 3063 obj = NULL; 3064 } else if (lo_flags & RTLD_LO_EARLY) { 3065 /* 3066 * Do not call the init functions for early loaded 3067 * filtees. The image is still not initialized enough 3068 * for them to work. 3069 * 3070 * Our object is found by the global object list and 3071 * will be ordered among all init calls done right 3072 * before transferring control to main. 3073 */ 3074 } else { 3075 /* Make list of init functions to call. */ 3076 initlist_add_objects(obj, obj, &initlist); 3077 } 3078 /* 3079 * Process all no_delete or global objects here, given 3080 * them own DAGs to prevent their dependencies from being 3081 * unloaded. This has to be done after we have loaded all 3082 * of the dependencies, so that we do not miss any. 3083 */ 3084 if (obj != NULL) 3085 process_z(obj); 3086 } else { 3087 /* 3088 * Bump the reference counts for objects on this DAG. If 3089 * this is the first dlopen() call for the object that was 3090 * already loaded as a dependency, initialize the dag 3091 * starting at it. 3092 */ 3093 init_dag(obj); 3094 ref_dag(obj); 3095 3096 if ((lo_flags & RTLD_LO_TRACE) != 0) 3097 goto trace; 3098 } 3099 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3100 obj->z_nodelete) && !obj->ref_nodel) { 3101 dbg("obj %s nodelete", obj->path); 3102 ref_dag(obj); 3103 obj->z_nodelete = obj->ref_nodel = true; 3104 } 3105 } 3106 3107 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3108 name); 3109 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3110 3111 if (!(lo_flags & RTLD_LO_EARLY)) { 3112 map_stacks_exec(lockstate); 3113 } 3114 3115 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3116 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3117 lockstate) == -1) { 3118 objlist_clear(&initlist); 3119 dlopen_cleanup(obj); 3120 if (lockstate == &mlockstate) 3121 lock_release(rtld_bind_lock, lockstate); 3122 return (NULL); 3123 } 3124 3125 if (!(lo_flags & RTLD_LO_EARLY)) { 3126 /* Call the init functions. */ 3127 objlist_call_init(&initlist, lockstate); 3128 } 3129 objlist_clear(&initlist); 3130 if (lockstate == &mlockstate) 3131 lock_release(rtld_bind_lock, lockstate); 3132 return obj; 3133trace: 3134 trace_loaded_objects(obj); 3135 if (lockstate == &mlockstate) 3136 lock_release(rtld_bind_lock, lockstate); 3137 exit(0); 3138} 3139 3140static void * 3141do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3142 int flags) 3143{ 3144 DoneList donelist; 3145 const Obj_Entry *obj, *defobj; 3146 const Elf_Sym *def; 3147 SymLook req; 3148 RtldLockState lockstate; 3149#ifndef __ia64__ 3150 tls_index ti; 3151#endif 3152 void *sym; 3153 int res; 3154 3155 def = NULL; 3156 defobj = NULL; 3157 symlook_init(&req, name); 3158 req.ventry = ve; 3159 req.flags = flags | SYMLOOK_IN_PLT; 3160 req.lockstate = &lockstate; 3161 3162 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3163 rlock_acquire(rtld_bind_lock, &lockstate); 3164 if (sigsetjmp(lockstate.env, 0) != 0) 3165 lock_upgrade(rtld_bind_lock, &lockstate); 3166 if (handle == NULL || handle == RTLD_NEXT || 3167 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3168 3169 if ((obj = obj_from_addr(retaddr)) == NULL) { 3170 _rtld_error("Cannot determine caller's shared object"); 3171 lock_release(rtld_bind_lock, &lockstate); 3172 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3173 return NULL; 3174 } 3175 if (handle == NULL) { /* Just the caller's shared object. */ 3176 res = symlook_obj(&req, obj); 3177 if (res == 0) { 3178 def = req.sym_out; 3179 defobj = req.defobj_out; 3180 } 3181 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3182 handle == RTLD_SELF) { /* ... caller included */ 3183 if (handle == RTLD_NEXT) 3184 obj = globallist_next(obj); 3185 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3186 if (obj->marker) 3187 continue; 3188 res = symlook_obj(&req, obj); 3189 if (res == 0) { 3190 if (def == NULL || 3191 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3192 def = req.sym_out; 3193 defobj = req.defobj_out; 3194 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3195 break; 3196 } 3197 } 3198 } 3199 /* 3200 * Search the dynamic linker itself, and possibly resolve the 3201 * symbol from there. This is how the application links to 3202 * dynamic linker services such as dlopen. 3203 */ 3204 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3205 res = symlook_obj(&req, &obj_rtld); 3206 if (res == 0) { 3207 def = req.sym_out; 3208 defobj = req.defobj_out; 3209 } 3210 } 3211 } else { 3212 assert(handle == RTLD_DEFAULT); 3213 res = symlook_default(&req, obj); 3214 if (res == 0) { 3215 defobj = req.defobj_out; 3216 def = req.sym_out; 3217 } 3218 } 3219 } else { 3220 if ((obj = dlcheck(handle)) == NULL) { 3221 lock_release(rtld_bind_lock, &lockstate); 3222 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3223 return NULL; 3224 } 3225 3226 donelist_init(&donelist); 3227 if (obj->mainprog) { 3228 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3229 res = symlook_global(&req, &donelist); 3230 if (res == 0) { 3231 def = req.sym_out; 3232 defobj = req.defobj_out; 3233 } 3234 /* 3235 * Search the dynamic linker itself, and possibly resolve the 3236 * symbol from there. This is how the application links to 3237 * dynamic linker services such as dlopen. 3238 */ 3239 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3240 res = symlook_obj(&req, &obj_rtld); 3241 if (res == 0) { 3242 def = req.sym_out; 3243 defobj = req.defobj_out; 3244 } 3245 } 3246 } 3247 else { 3248 /* Search the whole DAG rooted at the given object. */ 3249 res = symlook_list(&req, &obj->dagmembers, &donelist); 3250 if (res == 0) { 3251 def = req.sym_out; 3252 defobj = req.defobj_out; 3253 } 3254 } 3255 } 3256 3257 if (def != NULL) { 3258 lock_release(rtld_bind_lock, &lockstate); 3259 3260 /* 3261 * The value required by the caller is derived from the value 3262 * of the symbol. For the ia64 architecture, we need to 3263 * construct a function descriptor which the caller can use to 3264 * call the function with the right 'gp' value. For other 3265 * architectures and for non-functions, the value is simply 3266 * the relocated value of the symbol. 3267 */ 3268 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3269 sym = make_function_pointer(def, defobj); 3270 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3271 sym = rtld_resolve_ifunc(defobj, def); 3272 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3273#ifdef __ia64__ 3274 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3275#else 3276 ti.ti_module = defobj->tlsindex; 3277 ti.ti_offset = def->st_value; 3278 sym = __tls_get_addr(&ti); 3279#endif 3280 } else 3281 sym = defobj->relocbase + def->st_value; 3282 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3283 return (sym); 3284 } 3285 3286 _rtld_error("Undefined symbol \"%s\"", name); 3287 lock_release(rtld_bind_lock, &lockstate); 3288 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3289 return NULL; 3290} 3291 3292void * 3293dlsym(void *handle, const char *name) 3294{ 3295 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3296 SYMLOOK_DLSYM); 3297} 3298 3299dlfunc_t 3300dlfunc(void *handle, const char *name) 3301{ 3302 union { 3303 void *d; 3304 dlfunc_t f; 3305 } rv; 3306 3307 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3308 SYMLOOK_DLSYM); 3309 return (rv.f); 3310} 3311 3312void * 3313dlvsym(void *handle, const char *name, const char *version) 3314{ 3315 Ver_Entry ventry; 3316 3317 ventry.name = version; 3318 ventry.file = NULL; 3319 ventry.hash = elf_hash(version); 3320 ventry.flags= 0; 3321 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3322 SYMLOOK_DLSYM); 3323} 3324 3325int 3326_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3327{ 3328 const Obj_Entry *obj; 3329 RtldLockState lockstate; 3330 3331 rlock_acquire(rtld_bind_lock, &lockstate); 3332 obj = obj_from_addr(addr); 3333 if (obj == NULL) { 3334 _rtld_error("No shared object contains address"); 3335 lock_release(rtld_bind_lock, &lockstate); 3336 return (0); 3337 } 3338 rtld_fill_dl_phdr_info(obj, phdr_info); 3339 lock_release(rtld_bind_lock, &lockstate); 3340 return (1); 3341} 3342 3343int 3344dladdr(const void *addr, Dl_info *info) 3345{ 3346 const Obj_Entry *obj; 3347 const Elf_Sym *def; 3348 void *symbol_addr; 3349 unsigned long symoffset; 3350 RtldLockState lockstate; 3351 3352 rlock_acquire(rtld_bind_lock, &lockstate); 3353 obj = obj_from_addr(addr); 3354 if (obj == NULL) { 3355 _rtld_error("No shared object contains address"); 3356 lock_release(rtld_bind_lock, &lockstate); 3357 return 0; 3358 } 3359 info->dli_fname = obj->path; 3360 info->dli_fbase = obj->mapbase; 3361 info->dli_saddr = (void *)0; 3362 info->dli_sname = NULL; 3363 3364 /* 3365 * Walk the symbol list looking for the symbol whose address is 3366 * closest to the address sent in. 3367 */ 3368 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3369 def = obj->symtab + symoffset; 3370 3371 /* 3372 * For skip the symbol if st_shndx is either SHN_UNDEF or 3373 * SHN_COMMON. 3374 */ 3375 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3376 continue; 3377 3378 /* 3379 * If the symbol is greater than the specified address, or if it 3380 * is further away from addr than the current nearest symbol, 3381 * then reject it. 3382 */ 3383 symbol_addr = obj->relocbase + def->st_value; 3384 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3385 continue; 3386 3387 /* Update our idea of the nearest symbol. */ 3388 info->dli_sname = obj->strtab + def->st_name; 3389 info->dli_saddr = symbol_addr; 3390 3391 /* Exact match? */ 3392 if (info->dli_saddr == addr) 3393 break; 3394 } 3395 lock_release(rtld_bind_lock, &lockstate); 3396 return 1; 3397} 3398 3399int 3400dlinfo(void *handle, int request, void *p) 3401{ 3402 const Obj_Entry *obj; 3403 RtldLockState lockstate; 3404 int error; 3405 3406 rlock_acquire(rtld_bind_lock, &lockstate); 3407 3408 if (handle == NULL || handle == RTLD_SELF) { 3409 void *retaddr; 3410 3411 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3412 if ((obj = obj_from_addr(retaddr)) == NULL) 3413 _rtld_error("Cannot determine caller's shared object"); 3414 } else 3415 obj = dlcheck(handle); 3416 3417 if (obj == NULL) { 3418 lock_release(rtld_bind_lock, &lockstate); 3419 return (-1); 3420 } 3421 3422 error = 0; 3423 switch (request) { 3424 case RTLD_DI_LINKMAP: 3425 *((struct link_map const **)p) = &obj->linkmap; 3426 break; 3427 case RTLD_DI_ORIGIN: 3428 error = rtld_dirname(obj->path, p); 3429 break; 3430 3431 case RTLD_DI_SERINFOSIZE: 3432 case RTLD_DI_SERINFO: 3433 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3434 break; 3435 3436 default: 3437 _rtld_error("Invalid request %d passed to dlinfo()", request); 3438 error = -1; 3439 } 3440 3441 lock_release(rtld_bind_lock, &lockstate); 3442 3443 return (error); 3444} 3445 3446static void 3447rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3448{ 3449 3450 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3451 phdr_info->dlpi_name = obj->path; 3452 phdr_info->dlpi_phdr = obj->phdr; 3453 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3454 phdr_info->dlpi_tls_modid = obj->tlsindex; 3455 phdr_info->dlpi_tls_data = obj->tlsinit; 3456 phdr_info->dlpi_adds = obj_loads; 3457 phdr_info->dlpi_subs = obj_loads - obj_count; 3458} 3459 3460int 3461dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3462{ 3463 struct dl_phdr_info phdr_info; 3464 Obj_Entry *obj, marker; 3465 RtldLockState bind_lockstate, phdr_lockstate; 3466 int error; 3467 3468 bzero(&marker, sizeof(marker)); 3469 marker.marker = true; 3470 error = 0; 3471 3472 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3473 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3474 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3475 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3476 rtld_fill_dl_phdr_info(obj, &phdr_info); 3477 lock_release(rtld_bind_lock, &bind_lockstate); 3478 3479 error = callback(&phdr_info, sizeof phdr_info, param); 3480 3481 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3482 obj = globallist_next(&marker); 3483 TAILQ_REMOVE(&obj_list, &marker, next); 3484 if (error != 0) { 3485 lock_release(rtld_bind_lock, &bind_lockstate); 3486 lock_release(rtld_phdr_lock, &phdr_lockstate); 3487 return (error); 3488 } 3489 } 3490 3491 if (error == 0) { 3492 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3493 lock_release(rtld_bind_lock, &bind_lockstate); 3494 error = callback(&phdr_info, sizeof(phdr_info), param); 3495 } 3496 lock_release(rtld_phdr_lock, &phdr_lockstate); 3497 return (error); 3498} 3499 3500static void * 3501fill_search_info(const char *dir, size_t dirlen, void *param) 3502{ 3503 struct fill_search_info_args *arg; 3504 3505 arg = param; 3506 3507 if (arg->request == RTLD_DI_SERINFOSIZE) { 3508 arg->serinfo->dls_cnt ++; 3509 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3510 } else { 3511 struct dl_serpath *s_entry; 3512 3513 s_entry = arg->serpath; 3514 s_entry->dls_name = arg->strspace; 3515 s_entry->dls_flags = arg->flags; 3516 3517 strncpy(arg->strspace, dir, dirlen); 3518 arg->strspace[dirlen] = '\0'; 3519 3520 arg->strspace += dirlen + 1; 3521 arg->serpath++; 3522 } 3523 3524 return (NULL); 3525} 3526 3527static int 3528do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3529{ 3530 struct dl_serinfo _info; 3531 struct fill_search_info_args args; 3532 3533 args.request = RTLD_DI_SERINFOSIZE; 3534 args.serinfo = &_info; 3535 3536 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3537 _info.dls_cnt = 0; 3538 3539 path_enumerate(obj->rpath, fill_search_info, &args); 3540 path_enumerate(ld_library_path, fill_search_info, &args); 3541 path_enumerate(obj->runpath, fill_search_info, &args); 3542 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3543 if (!obj->z_nodeflib) 3544 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3545 3546 3547 if (request == RTLD_DI_SERINFOSIZE) { 3548 info->dls_size = _info.dls_size; 3549 info->dls_cnt = _info.dls_cnt; 3550 return (0); 3551 } 3552 3553 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3554 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3555 return (-1); 3556 } 3557 3558 args.request = RTLD_DI_SERINFO; 3559 args.serinfo = info; 3560 args.serpath = &info->dls_serpath[0]; 3561 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3562 3563 args.flags = LA_SER_RUNPATH; 3564 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3565 return (-1); 3566 3567 args.flags = LA_SER_LIBPATH; 3568 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3569 return (-1); 3570 3571 args.flags = LA_SER_RUNPATH; 3572 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3573 return (-1); 3574 3575 args.flags = LA_SER_CONFIG; 3576 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3577 != NULL) 3578 return (-1); 3579 3580 args.flags = LA_SER_DEFAULT; 3581 if (!obj->z_nodeflib && 3582 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3583 return (-1); 3584 return (0); 3585} 3586 3587static int 3588rtld_dirname(const char *path, char *bname) 3589{ 3590 const char *endp; 3591 3592 /* Empty or NULL string gets treated as "." */ 3593 if (path == NULL || *path == '\0') { 3594 bname[0] = '.'; 3595 bname[1] = '\0'; 3596 return (0); 3597 } 3598 3599 /* Strip trailing slashes */ 3600 endp = path + strlen(path) - 1; 3601 while (endp > path && *endp == '/') 3602 endp--; 3603 3604 /* Find the start of the dir */ 3605 while (endp > path && *endp != '/') 3606 endp--; 3607 3608 /* Either the dir is "/" or there are no slashes */ 3609 if (endp == path) { 3610 bname[0] = *endp == '/' ? '/' : '.'; 3611 bname[1] = '\0'; 3612 return (0); 3613 } else { 3614 do { 3615 endp--; 3616 } while (endp > path && *endp == '/'); 3617 } 3618 3619 if (endp - path + 2 > PATH_MAX) 3620 { 3621 _rtld_error("Filename is too long: %s", path); 3622 return(-1); 3623 } 3624 3625 strncpy(bname, path, endp - path + 1); 3626 bname[endp - path + 1] = '\0'; 3627 return (0); 3628} 3629 3630static int 3631rtld_dirname_abs(const char *path, char *base) 3632{ 3633 char *last; 3634 3635 if (realpath(path, base) == NULL) 3636 return (-1); 3637 dbg("%s -> %s", path, base); 3638 last = strrchr(base, '/'); 3639 if (last == NULL) 3640 return (-1); 3641 if (last != base) 3642 *last = '\0'; 3643 return (0); 3644} 3645 3646static void 3647linkmap_add(Obj_Entry *obj) 3648{ 3649 struct link_map *l = &obj->linkmap; 3650 struct link_map *prev; 3651 3652 obj->linkmap.l_name = obj->path; 3653 obj->linkmap.l_addr = obj->mapbase; 3654 obj->linkmap.l_ld = obj->dynamic; 3655#ifdef __mips__ 3656 /* GDB needs load offset on MIPS to use the symbols */ 3657 obj->linkmap.l_offs = obj->relocbase; 3658#endif 3659 3660 if (r_debug.r_map == NULL) { 3661 r_debug.r_map = l; 3662 return; 3663 } 3664 3665 /* 3666 * Scan to the end of the list, but not past the entry for the 3667 * dynamic linker, which we want to keep at the very end. 3668 */ 3669 for (prev = r_debug.r_map; 3670 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3671 prev = prev->l_next) 3672 ; 3673 3674 /* Link in the new entry. */ 3675 l->l_prev = prev; 3676 l->l_next = prev->l_next; 3677 if (l->l_next != NULL) 3678 l->l_next->l_prev = l; 3679 prev->l_next = l; 3680} 3681 3682static void 3683linkmap_delete(Obj_Entry *obj) 3684{ 3685 struct link_map *l = &obj->linkmap; 3686 3687 if (l->l_prev == NULL) { 3688 if ((r_debug.r_map = l->l_next) != NULL) 3689 l->l_next->l_prev = NULL; 3690 return; 3691 } 3692 3693 if ((l->l_prev->l_next = l->l_next) != NULL) 3694 l->l_next->l_prev = l->l_prev; 3695} 3696 3697/* 3698 * Function for the debugger to set a breakpoint on to gain control. 3699 * 3700 * The two parameters allow the debugger to easily find and determine 3701 * what the runtime loader is doing and to whom it is doing it. 3702 * 3703 * When the loadhook trap is hit (r_debug_state, set at program 3704 * initialization), the arguments can be found on the stack: 3705 * 3706 * +8 struct link_map *m 3707 * +4 struct r_debug *rd 3708 * +0 RetAddr 3709 */ 3710void 3711r_debug_state(struct r_debug* rd, struct link_map *m) 3712{ 3713 /* 3714 * The following is a hack to force the compiler to emit calls to 3715 * this function, even when optimizing. If the function is empty, 3716 * the compiler is not obliged to emit any code for calls to it, 3717 * even when marked __noinline. However, gdb depends on those 3718 * calls being made. 3719 */ 3720 __compiler_membar(); 3721} 3722 3723/* 3724 * A function called after init routines have completed. This can be used to 3725 * break before a program's entry routine is called, and can be used when 3726 * main is not available in the symbol table. 3727 */ 3728void 3729_r_debug_postinit(struct link_map *m) 3730{ 3731 3732 /* See r_debug_state(). */ 3733 __compiler_membar(); 3734} 3735 3736/* 3737 * Get address of the pointer variable in the main program. 3738 * Prefer non-weak symbol over the weak one. 3739 */ 3740static const void ** 3741get_program_var_addr(const char *name, RtldLockState *lockstate) 3742{ 3743 SymLook req; 3744 DoneList donelist; 3745 3746 symlook_init(&req, name); 3747 req.lockstate = lockstate; 3748 donelist_init(&donelist); 3749 if (symlook_global(&req, &donelist) != 0) 3750 return (NULL); 3751 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3752 return ((const void **)make_function_pointer(req.sym_out, 3753 req.defobj_out)); 3754 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3755 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3756 else 3757 return ((const void **)(req.defobj_out->relocbase + 3758 req.sym_out->st_value)); 3759} 3760 3761/* 3762 * Set a pointer variable in the main program to the given value. This 3763 * is used to set key variables such as "environ" before any of the 3764 * init functions are called. 3765 */ 3766static void 3767set_program_var(const char *name, const void *value) 3768{ 3769 const void **addr; 3770 3771 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3772 dbg("\"%s\": *%p <-- %p", name, addr, value); 3773 *addr = value; 3774 } 3775} 3776 3777/* 3778 * Search the global objects, including dependencies and main object, 3779 * for the given symbol. 3780 */ 3781static int 3782symlook_global(SymLook *req, DoneList *donelist) 3783{ 3784 SymLook req1; 3785 const Objlist_Entry *elm; 3786 int res; 3787 3788 symlook_init_from_req(&req1, req); 3789 3790 /* Search all objects loaded at program start up. */ 3791 if (req->defobj_out == NULL || 3792 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3793 res = symlook_list(&req1, &list_main, donelist); 3794 if (res == 0 && (req->defobj_out == NULL || 3795 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3796 req->sym_out = req1.sym_out; 3797 req->defobj_out = req1.defobj_out; 3798 assert(req->defobj_out != NULL); 3799 } 3800 } 3801 3802 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3803 STAILQ_FOREACH(elm, &list_global, link) { 3804 if (req->defobj_out != NULL && 3805 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3806 break; 3807 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3808 if (res == 0 && (req->defobj_out == NULL || 3809 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3810 req->sym_out = req1.sym_out; 3811 req->defobj_out = req1.defobj_out; 3812 assert(req->defobj_out != NULL); 3813 } 3814 } 3815 3816 return (req->sym_out != NULL ? 0 : ESRCH); 3817} 3818 3819/* 3820 * Given a symbol name in a referencing object, find the corresponding 3821 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3822 * no definition was found. Returns a pointer to the Obj_Entry of the 3823 * defining object via the reference parameter DEFOBJ_OUT. 3824 */ 3825static int 3826symlook_default(SymLook *req, const Obj_Entry *refobj) 3827{ 3828 DoneList donelist; 3829 const Objlist_Entry *elm; 3830 SymLook req1; 3831 int res; 3832 3833 donelist_init(&donelist); 3834 symlook_init_from_req(&req1, req); 3835 3836 /* Look first in the referencing object if linked symbolically. */ 3837 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3838 res = symlook_obj(&req1, refobj); 3839 if (res == 0) { 3840 req->sym_out = req1.sym_out; 3841 req->defobj_out = req1.defobj_out; 3842 assert(req->defobj_out != NULL); 3843 } 3844 } 3845 3846 symlook_global(req, &donelist); 3847 3848 /* Search all dlopened DAGs containing the referencing object. */ 3849 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3850 if (req->sym_out != NULL && 3851 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3852 break; 3853 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3854 if (res == 0 && (req->sym_out == NULL || 3855 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3856 req->sym_out = req1.sym_out; 3857 req->defobj_out = req1.defobj_out; 3858 assert(req->defobj_out != NULL); 3859 } 3860 } 3861 3862 /* 3863 * Search the dynamic linker itself, and possibly resolve the 3864 * symbol from there. This is how the application links to 3865 * dynamic linker services such as dlopen. 3866 */ 3867 if (req->sym_out == NULL || 3868 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3869 res = symlook_obj(&req1, &obj_rtld); 3870 if (res == 0) { 3871 req->sym_out = req1.sym_out; 3872 req->defobj_out = req1.defobj_out; 3873 assert(req->defobj_out != NULL); 3874 } 3875 } 3876 3877 return (req->sym_out != NULL ? 0 : ESRCH); 3878} 3879 3880static int 3881symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3882{ 3883 const Elf_Sym *def; 3884 const Obj_Entry *defobj; 3885 const Objlist_Entry *elm; 3886 SymLook req1; 3887 int res; 3888 3889 def = NULL; 3890 defobj = NULL; 3891 STAILQ_FOREACH(elm, objlist, link) { 3892 if (donelist_check(dlp, elm->obj)) 3893 continue; 3894 symlook_init_from_req(&req1, req); 3895 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3896 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3897 def = req1.sym_out; 3898 defobj = req1.defobj_out; 3899 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3900 break; 3901 } 3902 } 3903 } 3904 if (def != NULL) { 3905 req->sym_out = def; 3906 req->defobj_out = defobj; 3907 return (0); 3908 } 3909 return (ESRCH); 3910} 3911 3912/* 3913 * Search the chain of DAGS cointed to by the given Needed_Entry 3914 * for a symbol of the given name. Each DAG is scanned completely 3915 * before advancing to the next one. Returns a pointer to the symbol, 3916 * or NULL if no definition was found. 3917 */ 3918static int 3919symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3920{ 3921 const Elf_Sym *def; 3922 const Needed_Entry *n; 3923 const Obj_Entry *defobj; 3924 SymLook req1; 3925 int res; 3926 3927 def = NULL; 3928 defobj = NULL; 3929 symlook_init_from_req(&req1, req); 3930 for (n = needed; n != NULL; n = n->next) { 3931 if (n->obj == NULL || 3932 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3933 continue; 3934 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3935 def = req1.sym_out; 3936 defobj = req1.defobj_out; 3937 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3938 break; 3939 } 3940 } 3941 if (def != NULL) { 3942 req->sym_out = def; 3943 req->defobj_out = defobj; 3944 return (0); 3945 } 3946 return (ESRCH); 3947} 3948 3949/* 3950 * Search the symbol table of a single shared object for a symbol of 3951 * the given name and version, if requested. Returns a pointer to the 3952 * symbol, or NULL if no definition was found. If the object is 3953 * filter, return filtered symbol from filtee. 3954 * 3955 * The symbol's hash value is passed in for efficiency reasons; that 3956 * eliminates many recomputations of the hash value. 3957 */ 3958int 3959symlook_obj(SymLook *req, const Obj_Entry *obj) 3960{ 3961 DoneList donelist; 3962 SymLook req1; 3963 int flags, res, mres; 3964 3965 /* 3966 * If there is at least one valid hash at this point, we prefer to 3967 * use the faster GNU version if available. 3968 */ 3969 if (obj->valid_hash_gnu) 3970 mres = symlook_obj1_gnu(req, obj); 3971 else if (obj->valid_hash_sysv) 3972 mres = symlook_obj1_sysv(req, obj); 3973 else 3974 return (EINVAL); 3975 3976 if (mres == 0) { 3977 if (obj->needed_filtees != NULL) { 3978 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3979 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3980 donelist_init(&donelist); 3981 symlook_init_from_req(&req1, req); 3982 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3983 if (res == 0) { 3984 req->sym_out = req1.sym_out; 3985 req->defobj_out = req1.defobj_out; 3986 } 3987 return (res); 3988 } 3989 if (obj->needed_aux_filtees != NULL) { 3990 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3991 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3992 donelist_init(&donelist); 3993 symlook_init_from_req(&req1, req); 3994 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3995 if (res == 0) { 3996 req->sym_out = req1.sym_out; 3997 req->defobj_out = req1.defobj_out; 3998 return (res); 3999 } 4000 } 4001 } 4002 return (mres); 4003} 4004 4005/* Symbol match routine common to both hash functions */ 4006static bool 4007matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4008 const unsigned long symnum) 4009{ 4010 Elf_Versym verndx; 4011 const Elf_Sym *symp; 4012 const char *strp; 4013 4014 symp = obj->symtab + symnum; 4015 strp = obj->strtab + symp->st_name; 4016 4017 switch (ELF_ST_TYPE(symp->st_info)) { 4018 case STT_FUNC: 4019 case STT_NOTYPE: 4020 case STT_OBJECT: 4021 case STT_COMMON: 4022 case STT_GNU_IFUNC: 4023 if (symp->st_value == 0) 4024 return (false); 4025 /* fallthrough */ 4026 case STT_TLS: 4027 if (symp->st_shndx != SHN_UNDEF) 4028 break; 4029#ifndef __mips__ 4030 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4031 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4032 break; 4033 /* fallthrough */ 4034#endif 4035 default: 4036 return (false); 4037 } 4038 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4039 return (false); 4040 4041 if (req->ventry == NULL) { 4042 if (obj->versyms != NULL) { 4043 verndx = VER_NDX(obj->versyms[symnum]); 4044 if (verndx > obj->vernum) { 4045 _rtld_error( 4046 "%s: symbol %s references wrong version %d", 4047 obj->path, obj->strtab + symnum, verndx); 4048 return (false); 4049 } 4050 /* 4051 * If we are not called from dlsym (i.e. this 4052 * is a normal relocation from unversioned 4053 * binary), accept the symbol immediately if 4054 * it happens to have first version after this 4055 * shared object became versioned. Otherwise, 4056 * if symbol is versioned and not hidden, 4057 * remember it. If it is the only symbol with 4058 * this name exported by the shared object, it 4059 * will be returned as a match by the calling 4060 * function. If symbol is global (verndx < 2) 4061 * accept it unconditionally. 4062 */ 4063 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4064 verndx == VER_NDX_GIVEN) { 4065 result->sym_out = symp; 4066 return (true); 4067 } 4068 else if (verndx >= VER_NDX_GIVEN) { 4069 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4070 == 0) { 4071 if (result->vsymp == NULL) 4072 result->vsymp = symp; 4073 result->vcount++; 4074 } 4075 return (false); 4076 } 4077 } 4078 result->sym_out = symp; 4079 return (true); 4080 } 4081 if (obj->versyms == NULL) { 4082 if (object_match_name(obj, req->ventry->name)) { 4083 _rtld_error("%s: object %s should provide version %s " 4084 "for symbol %s", obj_rtld.path, obj->path, 4085 req->ventry->name, obj->strtab + symnum); 4086 return (false); 4087 } 4088 } else { 4089 verndx = VER_NDX(obj->versyms[symnum]); 4090 if (verndx > obj->vernum) { 4091 _rtld_error("%s: symbol %s references wrong version %d", 4092 obj->path, obj->strtab + symnum, verndx); 4093 return (false); 4094 } 4095 if (obj->vertab[verndx].hash != req->ventry->hash || 4096 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4097 /* 4098 * Version does not match. Look if this is a 4099 * global symbol and if it is not hidden. If 4100 * global symbol (verndx < 2) is available, 4101 * use it. Do not return symbol if we are 4102 * called by dlvsym, because dlvsym looks for 4103 * a specific version and default one is not 4104 * what dlvsym wants. 4105 */ 4106 if ((req->flags & SYMLOOK_DLSYM) || 4107 (verndx >= VER_NDX_GIVEN) || 4108 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4109 return (false); 4110 } 4111 } 4112 result->sym_out = symp; 4113 return (true); 4114} 4115 4116/* 4117 * Search for symbol using SysV hash function. 4118 * obj->buckets is known not to be NULL at this point; the test for this was 4119 * performed with the obj->valid_hash_sysv assignment. 4120 */ 4121static int 4122symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4123{ 4124 unsigned long symnum; 4125 Sym_Match_Result matchres; 4126 4127 matchres.sym_out = NULL; 4128 matchres.vsymp = NULL; 4129 matchres.vcount = 0; 4130 4131 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4132 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4133 if (symnum >= obj->nchains) 4134 return (ESRCH); /* Bad object */ 4135 4136 if (matched_symbol(req, obj, &matchres, symnum)) { 4137 req->sym_out = matchres.sym_out; 4138 req->defobj_out = obj; 4139 return (0); 4140 } 4141 } 4142 if (matchres.vcount == 1) { 4143 req->sym_out = matchres.vsymp; 4144 req->defobj_out = obj; 4145 return (0); 4146 } 4147 return (ESRCH); 4148} 4149 4150/* Search for symbol using GNU hash function */ 4151static int 4152symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4153{ 4154 Elf_Addr bloom_word; 4155 const Elf32_Word *hashval; 4156 Elf32_Word bucket; 4157 Sym_Match_Result matchres; 4158 unsigned int h1, h2; 4159 unsigned long symnum; 4160 4161 matchres.sym_out = NULL; 4162 matchres.vsymp = NULL; 4163 matchres.vcount = 0; 4164 4165 /* Pick right bitmask word from Bloom filter array */ 4166 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4167 obj->maskwords_bm_gnu]; 4168 4169 /* Calculate modulus word size of gnu hash and its derivative */ 4170 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4171 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4172 4173 /* Filter out the "definitely not in set" queries */ 4174 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4175 return (ESRCH); 4176 4177 /* Locate hash chain and corresponding value element*/ 4178 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4179 if (bucket == 0) 4180 return (ESRCH); 4181 hashval = &obj->chain_zero_gnu[bucket]; 4182 do { 4183 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4184 symnum = hashval - obj->chain_zero_gnu; 4185 if (matched_symbol(req, obj, &matchres, symnum)) { 4186 req->sym_out = matchres.sym_out; 4187 req->defobj_out = obj; 4188 return (0); 4189 } 4190 } 4191 } while ((*hashval++ & 1) == 0); 4192 if (matchres.vcount == 1) { 4193 req->sym_out = matchres.vsymp; 4194 req->defobj_out = obj; 4195 return (0); 4196 } 4197 return (ESRCH); 4198} 4199 4200static void 4201trace_loaded_objects(Obj_Entry *obj) 4202{ 4203 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4204 int c; 4205 4206 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4207 main_local = ""; 4208 4209 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4210 fmt1 = "\t%o => %p (%x)\n"; 4211 4212 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4213 fmt2 = "\t%o (%x)\n"; 4214 4215 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4216 4217 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4218 Needed_Entry *needed; 4219 char *name, *path; 4220 bool is_lib; 4221 4222 if (obj->marker) 4223 continue; 4224 if (list_containers && obj->needed != NULL) 4225 rtld_printf("%s:\n", obj->path); 4226 for (needed = obj->needed; needed; needed = needed->next) { 4227 if (needed->obj != NULL) { 4228 if (needed->obj->traced && !list_containers) 4229 continue; 4230 needed->obj->traced = true; 4231 path = needed->obj->path; 4232 } else 4233 path = "not found"; 4234 4235 name = (char *)obj->strtab + needed->name; 4236 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4237 4238 fmt = is_lib ? fmt1 : fmt2; 4239 while ((c = *fmt++) != '\0') { 4240 switch (c) { 4241 default: 4242 rtld_putchar(c); 4243 continue; 4244 case '\\': 4245 switch (c = *fmt) { 4246 case '\0': 4247 continue; 4248 case 'n': 4249 rtld_putchar('\n'); 4250 break; 4251 case 't': 4252 rtld_putchar('\t'); 4253 break; 4254 } 4255 break; 4256 case '%': 4257 switch (c = *fmt) { 4258 case '\0': 4259 continue; 4260 case '%': 4261 default: 4262 rtld_putchar(c); 4263 break; 4264 case 'A': 4265 rtld_putstr(main_local); 4266 break; 4267 case 'a': 4268 rtld_putstr(obj_main->path); 4269 break; 4270 case 'o': 4271 rtld_putstr(name); 4272 break; 4273#if 0 4274 case 'm': 4275 rtld_printf("%d", sodp->sod_major); 4276 break; 4277 case 'n': 4278 rtld_printf("%d", sodp->sod_minor); 4279 break; 4280#endif 4281 case 'p': 4282 rtld_putstr(path); 4283 break; 4284 case 'x': 4285 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4286 0); 4287 break; 4288 } 4289 break; 4290 } 4291 ++fmt; 4292 } 4293 } 4294 } 4295} 4296 4297/* 4298 * Unload a dlopened object and its dependencies from memory and from 4299 * our data structures. It is assumed that the DAG rooted in the 4300 * object has already been unreferenced, and that the object has a 4301 * reference count of 0. 4302 */ 4303static void 4304unload_object(Obj_Entry *root) 4305{ 4306 Obj_Entry *obj, *obj1; 4307 4308 assert(root->refcount == 0); 4309 4310 /* 4311 * Pass over the DAG removing unreferenced objects from 4312 * appropriate lists. 4313 */ 4314 unlink_object(root); 4315 4316 /* Unmap all objects that are no longer referenced. */ 4317 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4318 if (obj->marker || obj->refcount != 0) 4319 continue; 4320 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4321 obj->mapsize, 0, obj->path); 4322 dbg("unloading \"%s\"", obj->path); 4323 unload_filtees(root); 4324 munmap(obj->mapbase, obj->mapsize); 4325 linkmap_delete(obj); 4326 TAILQ_REMOVE(&obj_list, obj, next); 4327 obj_count--; 4328 obj_free(obj); 4329 } 4330} 4331 4332static void 4333unlink_object(Obj_Entry *root) 4334{ 4335 Objlist_Entry *elm; 4336 4337 if (root->refcount == 0) { 4338 /* Remove the object from the RTLD_GLOBAL list. */ 4339 objlist_remove(&list_global, root); 4340 4341 /* Remove the object from all objects' DAG lists. */ 4342 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4343 objlist_remove(&elm->obj->dldags, root); 4344 if (elm->obj != root) 4345 unlink_object(elm->obj); 4346 } 4347 } 4348} 4349 4350static void 4351ref_dag(Obj_Entry *root) 4352{ 4353 Objlist_Entry *elm; 4354 4355 assert(root->dag_inited); 4356 STAILQ_FOREACH(elm, &root->dagmembers, link) 4357 elm->obj->refcount++; 4358} 4359 4360static void 4361unref_dag(Obj_Entry *root) 4362{ 4363 Objlist_Entry *elm; 4364 4365 assert(root->dag_inited); 4366 STAILQ_FOREACH(elm, &root->dagmembers, link) 4367 elm->obj->refcount--; 4368} 4369 4370/* 4371 * Common code for MD __tls_get_addr(). 4372 */ 4373static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4374static void * 4375tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4376{ 4377 Elf_Addr *newdtv, *dtv; 4378 RtldLockState lockstate; 4379 int to_copy; 4380 4381 dtv = *dtvp; 4382 /* Check dtv generation in case new modules have arrived */ 4383 if (dtv[0] != tls_dtv_generation) { 4384 wlock_acquire(rtld_bind_lock, &lockstate); 4385 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4386 to_copy = dtv[1]; 4387 if (to_copy > tls_max_index) 4388 to_copy = tls_max_index; 4389 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4390 newdtv[0] = tls_dtv_generation; 4391 newdtv[1] = tls_max_index; 4392 free(dtv); 4393 lock_release(rtld_bind_lock, &lockstate); 4394 dtv = *dtvp = newdtv; 4395 } 4396 4397 /* Dynamically allocate module TLS if necessary */ 4398 if (dtv[index + 1] == 0) { 4399 /* Signal safe, wlock will block out signals. */ 4400 wlock_acquire(rtld_bind_lock, &lockstate); 4401 if (!dtv[index + 1]) 4402 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4403 lock_release(rtld_bind_lock, &lockstate); 4404 } 4405 return ((void *)(dtv[index + 1] + offset)); 4406} 4407 4408void * 4409tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4410{ 4411 Elf_Addr *dtv; 4412 4413 dtv = *dtvp; 4414 /* Check dtv generation in case new modules have arrived */ 4415 if (__predict_true(dtv[0] == tls_dtv_generation && 4416 dtv[index + 1] != 0)) 4417 return ((void *)(dtv[index + 1] + offset)); 4418 return (tls_get_addr_slow(dtvp, index, offset)); 4419} 4420 4421#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4422 4423/* 4424 * Allocate Static TLS using the Variant I method. 4425 */ 4426void * 4427allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4428{ 4429 Obj_Entry *obj; 4430 char *tcb; 4431 Elf_Addr **tls; 4432 Elf_Addr *dtv; 4433 Elf_Addr addr; 4434 int i; 4435 4436 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4437 return (oldtcb); 4438 4439 assert(tcbsize >= TLS_TCB_SIZE); 4440 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4441 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4442 4443 if (oldtcb != NULL) { 4444 memcpy(tls, oldtcb, tls_static_space); 4445 free(oldtcb); 4446 4447 /* Adjust the DTV. */ 4448 dtv = tls[0]; 4449 for (i = 0; i < dtv[1]; i++) { 4450 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4451 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4452 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4453 } 4454 } 4455 } else { 4456 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4457 tls[0] = dtv; 4458 dtv[0] = tls_dtv_generation; 4459 dtv[1] = tls_max_index; 4460 4461 for (obj = globallist_curr(objs); obj != NULL; 4462 obj = globallist_next(obj)) { 4463 if (obj->tlsoffset > 0) { 4464 addr = (Elf_Addr)tls + obj->tlsoffset; 4465 if (obj->tlsinitsize > 0) 4466 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4467 if (obj->tlssize > obj->tlsinitsize) 4468 memset((void*) (addr + obj->tlsinitsize), 0, 4469 obj->tlssize - obj->tlsinitsize); 4470 dtv[obj->tlsindex + 1] = addr; 4471 } 4472 } 4473 } 4474 4475 return (tcb); 4476} 4477 4478void 4479free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4480{ 4481 Elf_Addr *dtv; 4482 Elf_Addr tlsstart, tlsend; 4483 int dtvsize, i; 4484 4485 assert(tcbsize >= TLS_TCB_SIZE); 4486 4487 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4488 tlsend = tlsstart + tls_static_space; 4489 4490 dtv = *(Elf_Addr **)tlsstart; 4491 dtvsize = dtv[1]; 4492 for (i = 0; i < dtvsize; i++) { 4493 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4494 free((void*)dtv[i+2]); 4495 } 4496 } 4497 free(dtv); 4498 free(tcb); 4499} 4500 4501#endif 4502 4503#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4504 4505/* 4506 * Allocate Static TLS using the Variant II method. 4507 */ 4508void * 4509allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4510{ 4511 Obj_Entry *obj; 4512 size_t size, ralign; 4513 char *tls; 4514 Elf_Addr *dtv, *olddtv; 4515 Elf_Addr segbase, oldsegbase, addr; 4516 int i; 4517 4518 ralign = tcbalign; 4519 if (tls_static_max_align > ralign) 4520 ralign = tls_static_max_align; 4521 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4522 4523 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4524 tls = malloc_aligned(size, ralign); 4525 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4526 4527 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4528 ((Elf_Addr*)segbase)[0] = segbase; 4529 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4530 4531 dtv[0] = tls_dtv_generation; 4532 dtv[1] = tls_max_index; 4533 4534 if (oldtls) { 4535 /* 4536 * Copy the static TLS block over whole. 4537 */ 4538 oldsegbase = (Elf_Addr) oldtls; 4539 memcpy((void *)(segbase - tls_static_space), 4540 (const void *)(oldsegbase - tls_static_space), 4541 tls_static_space); 4542 4543 /* 4544 * If any dynamic TLS blocks have been created tls_get_addr(), 4545 * move them over. 4546 */ 4547 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4548 for (i = 0; i < olddtv[1]; i++) { 4549 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4550 dtv[i+2] = olddtv[i+2]; 4551 olddtv[i+2] = 0; 4552 } 4553 } 4554 4555 /* 4556 * We assume that this block was the one we created with 4557 * allocate_initial_tls(). 4558 */ 4559 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4560 } else { 4561 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4562 if (obj->marker || obj->tlsoffset == 0) 4563 continue; 4564 addr = segbase - obj->tlsoffset; 4565 memset((void*) (addr + obj->tlsinitsize), 4566 0, obj->tlssize - obj->tlsinitsize); 4567 if (obj->tlsinit) 4568 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4569 dtv[obj->tlsindex + 1] = addr; 4570 } 4571 } 4572 4573 return (void*) segbase; 4574} 4575 4576void 4577free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4578{ 4579 Elf_Addr* dtv; 4580 size_t size, ralign; 4581 int dtvsize, i; 4582 Elf_Addr tlsstart, tlsend; 4583 4584 /* 4585 * Figure out the size of the initial TLS block so that we can 4586 * find stuff which ___tls_get_addr() allocated dynamically. 4587 */ 4588 ralign = tcbalign; 4589 if (tls_static_max_align > ralign) 4590 ralign = tls_static_max_align; 4591 size = round(tls_static_space, ralign); 4592 4593 dtv = ((Elf_Addr**)tls)[1]; 4594 dtvsize = dtv[1]; 4595 tlsend = (Elf_Addr) tls; 4596 tlsstart = tlsend - size; 4597 for (i = 0; i < dtvsize; i++) { 4598 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4599 free_aligned((void *)dtv[i + 2]); 4600 } 4601 } 4602 4603 free_aligned((void *)tlsstart); 4604 free((void*) dtv); 4605} 4606 4607#endif 4608 4609/* 4610 * Allocate TLS block for module with given index. 4611 */ 4612void * 4613allocate_module_tls(int index) 4614{ 4615 Obj_Entry* obj; 4616 char* p; 4617 4618 TAILQ_FOREACH(obj, &obj_list, next) { 4619 if (obj->marker) 4620 continue; 4621 if (obj->tlsindex == index) 4622 break; 4623 } 4624 if (!obj) { 4625 _rtld_error("Can't find module with TLS index %d", index); 4626 rtld_die(); 4627 } 4628 4629 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4630 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4631 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4632 4633 return p; 4634} 4635 4636bool 4637allocate_tls_offset(Obj_Entry *obj) 4638{ 4639 size_t off; 4640 4641 if (obj->tls_done) 4642 return true; 4643 4644 if (obj->tlssize == 0) { 4645 obj->tls_done = true; 4646 return true; 4647 } 4648 4649 if (tls_last_offset == 0) 4650 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4651 else 4652 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4653 obj->tlssize, obj->tlsalign); 4654 4655 /* 4656 * If we have already fixed the size of the static TLS block, we 4657 * must stay within that size. When allocating the static TLS, we 4658 * leave a small amount of space spare to be used for dynamically 4659 * loading modules which use static TLS. 4660 */ 4661 if (tls_static_space != 0) { 4662 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4663 return false; 4664 } else if (obj->tlsalign > tls_static_max_align) { 4665 tls_static_max_align = obj->tlsalign; 4666 } 4667 4668 tls_last_offset = obj->tlsoffset = off; 4669 tls_last_size = obj->tlssize; 4670 obj->tls_done = true; 4671 4672 return true; 4673} 4674 4675void 4676free_tls_offset(Obj_Entry *obj) 4677{ 4678 4679 /* 4680 * If we were the last thing to allocate out of the static TLS 4681 * block, we give our space back to the 'allocator'. This is a 4682 * simplistic workaround to allow libGL.so.1 to be loaded and 4683 * unloaded multiple times. 4684 */ 4685 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4686 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4687 tls_last_offset -= obj->tlssize; 4688 tls_last_size = 0; 4689 } 4690} 4691 4692void * 4693_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4694{ 4695 void *ret; 4696 RtldLockState lockstate; 4697 4698 wlock_acquire(rtld_bind_lock, &lockstate); 4699 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4700 tcbsize, tcbalign); 4701 lock_release(rtld_bind_lock, &lockstate); 4702 return (ret); 4703} 4704 4705void 4706_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4707{ 4708 RtldLockState lockstate; 4709 4710 wlock_acquire(rtld_bind_lock, &lockstate); 4711 free_tls(tcb, tcbsize, tcbalign); 4712 lock_release(rtld_bind_lock, &lockstate); 4713} 4714 4715static void 4716object_add_name(Obj_Entry *obj, const char *name) 4717{ 4718 Name_Entry *entry; 4719 size_t len; 4720 4721 len = strlen(name); 4722 entry = malloc(sizeof(Name_Entry) + len); 4723 4724 if (entry != NULL) { 4725 strcpy(entry->name, name); 4726 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4727 } 4728} 4729 4730static int 4731object_match_name(const Obj_Entry *obj, const char *name) 4732{ 4733 Name_Entry *entry; 4734 4735 STAILQ_FOREACH(entry, &obj->names, link) { 4736 if (strcmp(name, entry->name) == 0) 4737 return (1); 4738 } 4739 return (0); 4740} 4741 4742static Obj_Entry * 4743locate_dependency(const Obj_Entry *obj, const char *name) 4744{ 4745 const Objlist_Entry *entry; 4746 const Needed_Entry *needed; 4747 4748 STAILQ_FOREACH(entry, &list_main, link) { 4749 if (object_match_name(entry->obj, name)) 4750 return entry->obj; 4751 } 4752 4753 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4754 if (strcmp(obj->strtab + needed->name, name) == 0 || 4755 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4756 /* 4757 * If there is DT_NEEDED for the name we are looking for, 4758 * we are all set. Note that object might not be found if 4759 * dependency was not loaded yet, so the function can 4760 * return NULL here. This is expected and handled 4761 * properly by the caller. 4762 */ 4763 return (needed->obj); 4764 } 4765 } 4766 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4767 obj->path, name); 4768 rtld_die(); 4769} 4770 4771static int 4772check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4773 const Elf_Vernaux *vna) 4774{ 4775 const Elf_Verdef *vd; 4776 const char *vername; 4777 4778 vername = refobj->strtab + vna->vna_name; 4779 vd = depobj->verdef; 4780 if (vd == NULL) { 4781 _rtld_error("%s: version %s required by %s not defined", 4782 depobj->path, vername, refobj->path); 4783 return (-1); 4784 } 4785 for (;;) { 4786 if (vd->vd_version != VER_DEF_CURRENT) { 4787 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4788 depobj->path, vd->vd_version); 4789 return (-1); 4790 } 4791 if (vna->vna_hash == vd->vd_hash) { 4792 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4793 ((char *)vd + vd->vd_aux); 4794 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4795 return (0); 4796 } 4797 if (vd->vd_next == 0) 4798 break; 4799 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4800 } 4801 if (vna->vna_flags & VER_FLG_WEAK) 4802 return (0); 4803 _rtld_error("%s: version %s required by %s not found", 4804 depobj->path, vername, refobj->path); 4805 return (-1); 4806} 4807 4808static int 4809rtld_verify_object_versions(Obj_Entry *obj) 4810{ 4811 const Elf_Verneed *vn; 4812 const Elf_Verdef *vd; 4813 const Elf_Verdaux *vda; 4814 const Elf_Vernaux *vna; 4815 const Obj_Entry *depobj; 4816 int maxvernum, vernum; 4817 4818 if (obj->ver_checked) 4819 return (0); 4820 obj->ver_checked = true; 4821 4822 maxvernum = 0; 4823 /* 4824 * Walk over defined and required version records and figure out 4825 * max index used by any of them. Do very basic sanity checking 4826 * while there. 4827 */ 4828 vn = obj->verneed; 4829 while (vn != NULL) { 4830 if (vn->vn_version != VER_NEED_CURRENT) { 4831 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4832 obj->path, vn->vn_version); 4833 return (-1); 4834 } 4835 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4836 for (;;) { 4837 vernum = VER_NEED_IDX(vna->vna_other); 4838 if (vernum > maxvernum) 4839 maxvernum = vernum; 4840 if (vna->vna_next == 0) 4841 break; 4842 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4843 } 4844 if (vn->vn_next == 0) 4845 break; 4846 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4847 } 4848 4849 vd = obj->verdef; 4850 while (vd != NULL) { 4851 if (vd->vd_version != VER_DEF_CURRENT) { 4852 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4853 obj->path, vd->vd_version); 4854 return (-1); 4855 } 4856 vernum = VER_DEF_IDX(vd->vd_ndx); 4857 if (vernum > maxvernum) 4858 maxvernum = vernum; 4859 if (vd->vd_next == 0) 4860 break; 4861 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4862 } 4863 4864 if (maxvernum == 0) 4865 return (0); 4866 4867 /* 4868 * Store version information in array indexable by version index. 4869 * Verify that object version requirements are satisfied along the 4870 * way. 4871 */ 4872 obj->vernum = maxvernum + 1; 4873 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4874 4875 vd = obj->verdef; 4876 while (vd != NULL) { 4877 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4878 vernum = VER_DEF_IDX(vd->vd_ndx); 4879 assert(vernum <= maxvernum); 4880 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4881 obj->vertab[vernum].hash = vd->vd_hash; 4882 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4883 obj->vertab[vernum].file = NULL; 4884 obj->vertab[vernum].flags = 0; 4885 } 4886 if (vd->vd_next == 0) 4887 break; 4888 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4889 } 4890 4891 vn = obj->verneed; 4892 while (vn != NULL) { 4893 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4894 if (depobj == NULL) 4895 return (-1); 4896 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4897 for (;;) { 4898 if (check_object_provided_version(obj, depobj, vna)) 4899 return (-1); 4900 vernum = VER_NEED_IDX(vna->vna_other); 4901 assert(vernum <= maxvernum); 4902 obj->vertab[vernum].hash = vna->vna_hash; 4903 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4904 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4905 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4906 VER_INFO_HIDDEN : 0; 4907 if (vna->vna_next == 0) 4908 break; 4909 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4910 } 4911 if (vn->vn_next == 0) 4912 break; 4913 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4914 } 4915 return 0; 4916} 4917 4918static int 4919rtld_verify_versions(const Objlist *objlist) 4920{ 4921 Objlist_Entry *entry; 4922 int rc; 4923 4924 rc = 0; 4925 STAILQ_FOREACH(entry, objlist, link) { 4926 /* 4927 * Skip dummy objects or objects that have their version requirements 4928 * already checked. 4929 */ 4930 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4931 continue; 4932 if (rtld_verify_object_versions(entry->obj) == -1) { 4933 rc = -1; 4934 if (ld_tracing == NULL) 4935 break; 4936 } 4937 } 4938 if (rc == 0 || ld_tracing != NULL) 4939 rc = rtld_verify_object_versions(&obj_rtld); 4940 return rc; 4941} 4942 4943const Ver_Entry * 4944fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4945{ 4946 Elf_Versym vernum; 4947 4948 if (obj->vertab) { 4949 vernum = VER_NDX(obj->versyms[symnum]); 4950 if (vernum >= obj->vernum) { 4951 _rtld_error("%s: symbol %s has wrong verneed value %d", 4952 obj->path, obj->strtab + symnum, vernum); 4953 } else if (obj->vertab[vernum].hash != 0) { 4954 return &obj->vertab[vernum]; 4955 } 4956 } 4957 return NULL; 4958} 4959 4960int 4961_rtld_get_stack_prot(void) 4962{ 4963 4964 return (stack_prot); 4965} 4966 4967int 4968_rtld_is_dlopened(void *arg) 4969{ 4970 Obj_Entry *obj; 4971 RtldLockState lockstate; 4972 int res; 4973 4974 rlock_acquire(rtld_bind_lock, &lockstate); 4975 obj = dlcheck(arg); 4976 if (obj == NULL) 4977 obj = obj_from_addr(arg); 4978 if (obj == NULL) { 4979 _rtld_error("No shared object contains address"); 4980 lock_release(rtld_bind_lock, &lockstate); 4981 return (-1); 4982 } 4983 res = obj->dlopened ? 1 : 0; 4984 lock_release(rtld_bind_lock, &lockstate); 4985 return (res); 4986} 4987 4988int 4989obj_enforce_relro(Obj_Entry *obj) 4990{ 4991 4992 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 4993 PROT_READ) == -1) { 4994 _rtld_error("%s: Cannot enforce relro protection: %s", 4995 obj->path, rtld_strerror(errno)); 4996 return (-1); 4997 } 4998 return (0); 4999} 5000 5001static void 5002map_stacks_exec(RtldLockState *lockstate) 5003{ 5004 void (*thr_map_stacks_exec)(void); 5005 5006 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5007 return; 5008 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5009 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5010 if (thr_map_stacks_exec != NULL) { 5011 stack_prot |= PROT_EXEC; 5012 thr_map_stacks_exec(); 5013 } 5014} 5015 5016void 5017symlook_init(SymLook *dst, const char *name) 5018{ 5019 5020 bzero(dst, sizeof(*dst)); 5021 dst->name = name; 5022 dst->hash = elf_hash(name); 5023 dst->hash_gnu = gnu_hash(name); 5024} 5025 5026static void 5027symlook_init_from_req(SymLook *dst, const SymLook *src) 5028{ 5029 5030 dst->name = src->name; 5031 dst->hash = src->hash; 5032 dst->hash_gnu = src->hash_gnu; 5033 dst->ventry = src->ventry; 5034 dst->flags = src->flags; 5035 dst->defobj_out = NULL; 5036 dst->sym_out = NULL; 5037 dst->lockstate = src->lockstate; 5038} 5039 5040/* 5041 * Overrides for libc_pic-provided functions. 5042 */ 5043 5044int 5045__getosreldate(void) 5046{ 5047 size_t len; 5048 int oid[2]; 5049 int error, osrel; 5050 5051 if (osreldate != 0) 5052 return (osreldate); 5053 5054 oid[0] = CTL_KERN; 5055 oid[1] = KERN_OSRELDATE; 5056 osrel = 0; 5057 len = sizeof(osrel); 5058 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5059 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5060 osreldate = osrel; 5061 return (osreldate); 5062} 5063 5064void 5065exit(int status) 5066{ 5067 5068 _exit(status); 5069} 5070 5071void (*__cleanup)(void); 5072int __isthreaded = 0; 5073int _thread_autoinit_dummy_decl = 1; 5074 5075/* 5076 * No unresolved symbols for rtld. 5077 */ 5078void 5079__pthread_cxa_finalize(struct dl_phdr_info *a) 5080{ 5081} 5082 5083void 5084__stack_chk_fail(void) 5085{ 5086 5087 _rtld_error("stack overflow detected; terminated"); 5088 rtld_die(); 5089} 5090__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5091 5092void 5093__chk_fail(void) 5094{ 5095 5096 _rtld_error("buffer overflow detected; terminated"); 5097 rtld_die(); 5098} 5099 5100const char * 5101rtld_strerror(int errnum) 5102{ 5103 5104 if (errnum < 0 || errnum >= sys_nerr) 5105 return ("Unknown error"); 5106 return (sys_errlist[errnum]); 5107} 5108