rtld.c revision 323877
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 323877 2017-09-21 20:59:36Z jhb $ 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_main->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 const Ver_Entry *ve; 1551 SymLook req; 1552 const char *name; 1553 int res; 1554 1555 /* 1556 * If we have already found this symbol, get the information from 1557 * the cache. 1558 */ 1559 if (symnum >= refobj->dynsymcount) 1560 return NULL; /* Bad object */ 1561 if (cache != NULL && cache[symnum].sym != NULL) { 1562 *defobj_out = cache[symnum].obj; 1563 return cache[symnum].sym; 1564 } 1565 1566 ref = refobj->symtab + symnum; 1567 name = refobj->strtab + ref->st_name; 1568 def = NULL; 1569 defobj = NULL; 1570 ve = NULL; 1571 1572 /* 1573 * We don't have to do a full scale lookup if the symbol is local. 1574 * We know it will bind to the instance in this load module; to 1575 * which we already have a pointer (ie ref). By not doing a lookup, 1576 * we not only improve performance, but it also avoids unresolvable 1577 * symbols when local symbols are not in the hash table. This has 1578 * been seen with the ia64 toolchain. 1579 */ 1580 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1581 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1582 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1583 symnum); 1584 } 1585 symlook_init(&req, name); 1586 req.flags = flags; 1587 ve = req.ventry = fetch_ventry(refobj, symnum); 1588 req.lockstate = lockstate; 1589 res = symlook_default(&req, refobj); 1590 if (res == 0) { 1591 def = req.sym_out; 1592 defobj = req.defobj_out; 1593 } 1594 } else { 1595 def = ref; 1596 defobj = refobj; 1597 } 1598 1599 /* 1600 * If we found no definition and the reference is weak, treat the 1601 * symbol as having the value zero. 1602 */ 1603 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1604 def = &sym_zero; 1605 defobj = obj_main; 1606 } 1607 1608 if (def != NULL) { 1609 *defobj_out = defobj; 1610 /* Record the information in the cache to avoid subsequent lookups. */ 1611 if (cache != NULL) { 1612 cache[symnum].sym = def; 1613 cache[symnum].obj = defobj; 1614 } 1615 } else { 1616 if (refobj != &obj_rtld) 1617 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1618 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1619 } 1620 return def; 1621} 1622 1623/* 1624 * Return the search path from the ldconfig hints file, reading it if 1625 * necessary. If nostdlib is true, then the default search paths are 1626 * not added to result. 1627 * 1628 * Returns NULL if there are problems with the hints file, 1629 * or if the search path there is empty. 1630 */ 1631static const char * 1632gethints(bool nostdlib) 1633{ 1634 static char *hints, *filtered_path; 1635 static struct elfhints_hdr hdr; 1636 struct fill_search_info_args sargs, hargs; 1637 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1638 struct dl_serpath *SLPpath, *hintpath; 1639 char *p; 1640 struct stat hint_stat; 1641 unsigned int SLPndx, hintndx, fndx, fcount; 1642 int fd; 1643 size_t flen; 1644 uint32_t dl; 1645 bool skip; 1646 1647 /* First call, read the hints file */ 1648 if (hints == NULL) { 1649 /* Keep from trying again in case the hints file is bad. */ 1650 hints = ""; 1651 1652 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1653 return (NULL); 1654 1655 /* 1656 * Check of hdr.dirlistlen value against type limit 1657 * intends to pacify static analyzers. Further 1658 * paranoia leads to checks that dirlist is fully 1659 * contained in the file range. 1660 */ 1661 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1662 hdr.magic != ELFHINTS_MAGIC || 1663 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1664 fstat(fd, &hint_stat) == -1) { 1665cleanup1: 1666 close(fd); 1667 hdr.dirlistlen = 0; 1668 return (NULL); 1669 } 1670 dl = hdr.strtab; 1671 if (dl + hdr.dirlist < dl) 1672 goto cleanup1; 1673 dl += hdr.dirlist; 1674 if (dl + hdr.dirlistlen < dl) 1675 goto cleanup1; 1676 dl += hdr.dirlistlen; 1677 if (dl > hint_stat.st_size) 1678 goto cleanup1; 1679 p = xmalloc(hdr.dirlistlen + 1); 1680 1681 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1682 read(fd, p, hdr.dirlistlen + 1) != 1683 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1684 free(p); 1685 goto cleanup1; 1686 } 1687 hints = p; 1688 close(fd); 1689 } 1690 1691 /* 1692 * If caller agreed to receive list which includes the default 1693 * paths, we are done. Otherwise, if we still did not 1694 * calculated filtered result, do it now. 1695 */ 1696 if (!nostdlib) 1697 return (hints[0] != '\0' ? hints : NULL); 1698 if (filtered_path != NULL) 1699 goto filt_ret; 1700 1701 /* 1702 * Obtain the list of all configured search paths, and the 1703 * list of the default paths. 1704 * 1705 * First estimate the size of the results. 1706 */ 1707 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1708 smeta.dls_cnt = 0; 1709 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1710 hmeta.dls_cnt = 0; 1711 1712 sargs.request = RTLD_DI_SERINFOSIZE; 1713 sargs.serinfo = &smeta; 1714 hargs.request = RTLD_DI_SERINFOSIZE; 1715 hargs.serinfo = &hmeta; 1716 1717 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1718 path_enumerate(hints, fill_search_info, &hargs); 1719 1720 SLPinfo = xmalloc(smeta.dls_size); 1721 hintinfo = xmalloc(hmeta.dls_size); 1722 1723 /* 1724 * Next fetch both sets of paths. 1725 */ 1726 sargs.request = RTLD_DI_SERINFO; 1727 sargs.serinfo = SLPinfo; 1728 sargs.serpath = &SLPinfo->dls_serpath[0]; 1729 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1730 1731 hargs.request = RTLD_DI_SERINFO; 1732 hargs.serinfo = hintinfo; 1733 hargs.serpath = &hintinfo->dls_serpath[0]; 1734 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1735 1736 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1737 path_enumerate(hints, fill_search_info, &hargs); 1738 1739 /* 1740 * Now calculate the difference between two sets, by excluding 1741 * standard paths from the full set. 1742 */ 1743 fndx = 0; 1744 fcount = 0; 1745 filtered_path = xmalloc(hdr.dirlistlen + 1); 1746 hintpath = &hintinfo->dls_serpath[0]; 1747 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1748 skip = false; 1749 SLPpath = &SLPinfo->dls_serpath[0]; 1750 /* 1751 * Check each standard path against current. 1752 */ 1753 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1754 /* matched, skip the path */ 1755 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1756 skip = true; 1757 break; 1758 } 1759 } 1760 if (skip) 1761 continue; 1762 /* 1763 * Not matched against any standard path, add the path 1764 * to result. Separate consequtive paths with ':'. 1765 */ 1766 if (fcount > 0) { 1767 filtered_path[fndx] = ':'; 1768 fndx++; 1769 } 1770 fcount++; 1771 flen = strlen(hintpath->dls_name); 1772 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1773 fndx += flen; 1774 } 1775 filtered_path[fndx] = '\0'; 1776 1777 free(SLPinfo); 1778 free(hintinfo); 1779 1780filt_ret: 1781 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1782} 1783 1784static void 1785init_dag(Obj_Entry *root) 1786{ 1787 const Needed_Entry *needed; 1788 const Objlist_Entry *elm; 1789 DoneList donelist; 1790 1791 if (root->dag_inited) 1792 return; 1793 donelist_init(&donelist); 1794 1795 /* Root object belongs to own DAG. */ 1796 objlist_push_tail(&root->dldags, root); 1797 objlist_push_tail(&root->dagmembers, root); 1798 donelist_check(&donelist, root); 1799 1800 /* 1801 * Add dependencies of root object to DAG in breadth order 1802 * by exploiting the fact that each new object get added 1803 * to the tail of the dagmembers list. 1804 */ 1805 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1806 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1807 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1808 continue; 1809 objlist_push_tail(&needed->obj->dldags, root); 1810 objlist_push_tail(&root->dagmembers, needed->obj); 1811 } 1812 } 1813 root->dag_inited = true; 1814} 1815 1816Obj_Entry * 1817globallist_curr(const Obj_Entry *obj) 1818{ 1819 1820 for (;;) { 1821 if (obj == NULL) 1822 return (NULL); 1823 if (!obj->marker) 1824 return (__DECONST(Obj_Entry *, obj)); 1825 obj = TAILQ_PREV(obj, obj_entry_q, next); 1826 } 1827} 1828 1829Obj_Entry * 1830globallist_next(const Obj_Entry *obj) 1831{ 1832 1833 for (;;) { 1834 obj = TAILQ_NEXT(obj, next); 1835 if (obj == NULL) 1836 return (NULL); 1837 if (!obj->marker) 1838 return (__DECONST(Obj_Entry *, obj)); 1839 } 1840} 1841 1842static void 1843process_z(Obj_Entry *root) 1844{ 1845 const Objlist_Entry *elm; 1846 Obj_Entry *obj; 1847 1848 /* 1849 * Walk over object DAG and process every dependent object 1850 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1851 * to grow their own DAG. 1852 * 1853 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1854 * symlook_global() to work. 1855 * 1856 * For DF_1_NODELETE, the DAG should have its reference upped. 1857 */ 1858 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1859 obj = elm->obj; 1860 if (obj == NULL) 1861 continue; 1862 if (obj->z_nodelete && !obj->ref_nodel) { 1863 dbg("obj %s -z nodelete", obj->path); 1864 init_dag(obj); 1865 ref_dag(obj); 1866 obj->ref_nodel = true; 1867 } 1868 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1869 dbg("obj %s -z global", obj->path); 1870 objlist_push_tail(&list_global, obj); 1871 init_dag(obj); 1872 } 1873 } 1874} 1875/* 1876 * Initialize the dynamic linker. The argument is the address at which 1877 * the dynamic linker has been mapped into memory. The primary task of 1878 * this function is to relocate the dynamic linker. 1879 */ 1880static void 1881init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1882{ 1883 Obj_Entry objtmp; /* Temporary rtld object */ 1884 const Elf_Ehdr *ehdr; 1885 const Elf_Dyn *dyn_rpath; 1886 const Elf_Dyn *dyn_soname; 1887 const Elf_Dyn *dyn_runpath; 1888 1889#ifdef RTLD_INIT_PAGESIZES_EARLY 1890 /* The page size is required by the dynamic memory allocator. */ 1891 init_pagesizes(aux_info); 1892#endif 1893 1894 /* 1895 * Conjure up an Obj_Entry structure for the dynamic linker. 1896 * 1897 * The "path" member can't be initialized yet because string constants 1898 * cannot yet be accessed. Below we will set it correctly. 1899 */ 1900 memset(&objtmp, 0, sizeof(objtmp)); 1901 objtmp.path = NULL; 1902 objtmp.rtld = true; 1903 objtmp.mapbase = mapbase; 1904#ifdef PIC 1905 objtmp.relocbase = mapbase; 1906#endif 1907 if (RTLD_IS_DYNAMIC()) { 1908 objtmp.dynamic = rtld_dynamic(&objtmp); 1909 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1910 assert(objtmp.needed == NULL); 1911#if !defined(__mips__) 1912 /* MIPS has a bogus DT_TEXTREL. */ 1913 assert(!objtmp.textrel); 1914#endif 1915 1916 /* 1917 * Temporarily put the dynamic linker entry into the object list, so 1918 * that symbols can be found. 1919 */ 1920 1921 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1922 } 1923 ehdr = (Elf_Ehdr *)mapbase; 1924 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1925 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1926 1927 /* Initialize the object list. */ 1928 TAILQ_INIT(&obj_list); 1929 1930 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1931 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1932 1933#ifndef RTLD_INIT_PAGESIZES_EARLY 1934 /* The page size is required by the dynamic memory allocator. */ 1935 init_pagesizes(aux_info); 1936#endif 1937 1938 if (aux_info[AT_OSRELDATE] != NULL) 1939 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1940 1941 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1942 1943 /* Replace the path with a dynamically allocated copy. */ 1944 obj_rtld.path = xstrdup(PATH_RTLD); 1945 1946 r_debug.r_brk = r_debug_state; 1947 r_debug.r_state = RT_CONSISTENT; 1948} 1949 1950/* 1951 * Retrieve the array of supported page sizes. The kernel provides the page 1952 * sizes in increasing order. 1953 */ 1954static void 1955init_pagesizes(Elf_Auxinfo **aux_info) 1956{ 1957 static size_t psa[MAXPAGESIZES]; 1958 int mib[2]; 1959 size_t len, size; 1960 1961 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1962 NULL) { 1963 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1964 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1965 } else { 1966 len = 2; 1967 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1968 size = sizeof(psa); 1969 else { 1970 /* As a fallback, retrieve the base page size. */ 1971 size = sizeof(psa[0]); 1972 if (aux_info[AT_PAGESZ] != NULL) { 1973 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1974 goto psa_filled; 1975 } else { 1976 mib[0] = CTL_HW; 1977 mib[1] = HW_PAGESIZE; 1978 len = 2; 1979 } 1980 } 1981 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1982 _rtld_error("sysctl for hw.pagesize(s) failed"); 1983 rtld_die(); 1984 } 1985psa_filled: 1986 pagesizes = psa; 1987 } 1988 npagesizes = size / sizeof(pagesizes[0]); 1989 /* Discard any invalid entries at the end of the array. */ 1990 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1991 npagesizes--; 1992} 1993 1994/* 1995 * Add the init functions from a needed object list (and its recursive 1996 * needed objects) to "list". This is not used directly; it is a helper 1997 * function for initlist_add_objects(). The write lock must be held 1998 * when this function is called. 1999 */ 2000static void 2001initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2002{ 2003 /* Recursively process the successor needed objects. */ 2004 if (needed->next != NULL) 2005 initlist_add_neededs(needed->next, list); 2006 2007 /* Process the current needed object. */ 2008 if (needed->obj != NULL) 2009 initlist_add_objects(needed->obj, needed->obj, list); 2010} 2011 2012/* 2013 * Scan all of the DAGs rooted in the range of objects from "obj" to 2014 * "tail" and add their init functions to "list". This recurses over 2015 * the DAGs and ensure the proper init ordering such that each object's 2016 * needed libraries are initialized before the object itself. At the 2017 * same time, this function adds the objects to the global finalization 2018 * list "list_fini" in the opposite order. The write lock must be 2019 * held when this function is called. 2020 */ 2021static void 2022initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2023{ 2024 Obj_Entry *nobj; 2025 2026 if (obj->init_scanned || obj->init_done) 2027 return; 2028 obj->init_scanned = true; 2029 2030 /* Recursively process the successor objects. */ 2031 nobj = globallist_next(obj); 2032 if (nobj != NULL && obj != tail) 2033 initlist_add_objects(nobj, tail, list); 2034 2035 /* Recursively process the needed objects. */ 2036 if (obj->needed != NULL) 2037 initlist_add_neededs(obj->needed, list); 2038 if (obj->needed_filtees != NULL) 2039 initlist_add_neededs(obj->needed_filtees, list); 2040 if (obj->needed_aux_filtees != NULL) 2041 initlist_add_neededs(obj->needed_aux_filtees, list); 2042 2043 /* Add the object to the init list. */ 2044 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2045 obj->init_array != (Elf_Addr)NULL) 2046 objlist_push_tail(list, obj); 2047 2048 /* Add the object to the global fini list in the reverse order. */ 2049 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2050 && !obj->on_fini_list) { 2051 objlist_push_head(&list_fini, obj); 2052 obj->on_fini_list = true; 2053 } 2054} 2055 2056#ifndef FPTR_TARGET 2057#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2058#endif 2059 2060static void 2061free_needed_filtees(Needed_Entry *n) 2062{ 2063 Needed_Entry *needed, *needed1; 2064 2065 for (needed = n; needed != NULL; needed = needed->next) { 2066 if (needed->obj != NULL) { 2067 dlclose(needed->obj); 2068 needed->obj = NULL; 2069 } 2070 } 2071 for (needed = n; needed != NULL; needed = needed1) { 2072 needed1 = needed->next; 2073 free(needed); 2074 } 2075} 2076 2077static void 2078unload_filtees(Obj_Entry *obj) 2079{ 2080 2081 free_needed_filtees(obj->needed_filtees); 2082 obj->needed_filtees = NULL; 2083 free_needed_filtees(obj->needed_aux_filtees); 2084 obj->needed_aux_filtees = NULL; 2085 obj->filtees_loaded = false; 2086} 2087 2088static void 2089load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2090 RtldLockState *lockstate) 2091{ 2092 2093 for (; needed != NULL; needed = needed->next) { 2094 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2095 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2096 RTLD_LOCAL, lockstate); 2097 } 2098} 2099 2100static void 2101load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2102{ 2103 2104 lock_restart_for_upgrade(lockstate); 2105 if (!obj->filtees_loaded) { 2106 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2107 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2108 obj->filtees_loaded = true; 2109 } 2110} 2111 2112static int 2113process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2114{ 2115 Obj_Entry *obj1; 2116 2117 for (; needed != NULL; needed = needed->next) { 2118 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2119 flags & ~RTLD_LO_NOLOAD); 2120 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2121 return (-1); 2122 } 2123 return (0); 2124} 2125 2126/* 2127 * Given a shared object, traverse its list of needed objects, and load 2128 * each of them. Returns 0 on success. Generates an error message and 2129 * returns -1 on failure. 2130 */ 2131static int 2132load_needed_objects(Obj_Entry *first, int flags) 2133{ 2134 Obj_Entry *obj; 2135 2136 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2137 if (obj->marker) 2138 continue; 2139 if (process_needed(obj, obj->needed, flags) == -1) 2140 return (-1); 2141 } 2142 return (0); 2143} 2144 2145static int 2146load_preload_objects(void) 2147{ 2148 char *p = ld_preload; 2149 Obj_Entry *obj; 2150 static const char delim[] = " \t:;"; 2151 2152 if (p == NULL) 2153 return 0; 2154 2155 p += strspn(p, delim); 2156 while (*p != '\0') { 2157 size_t len = strcspn(p, delim); 2158 char savech; 2159 2160 savech = p[len]; 2161 p[len] = '\0'; 2162 obj = load_object(p, -1, NULL, 0); 2163 if (obj == NULL) 2164 return -1; /* XXX - cleanup */ 2165 obj->z_interpose = true; 2166 p[len] = savech; 2167 p += len; 2168 p += strspn(p, delim); 2169 } 2170 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2171 return 0; 2172} 2173 2174static const char * 2175printable_path(const char *path) 2176{ 2177 2178 return (path == NULL ? "<unknown>" : path); 2179} 2180 2181/* 2182 * Load a shared object into memory, if it is not already loaded. The 2183 * object may be specified by name or by user-supplied file descriptor 2184 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2185 * duplicate is. 2186 * 2187 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2188 * on failure. 2189 */ 2190static Obj_Entry * 2191load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2192{ 2193 Obj_Entry *obj; 2194 int fd; 2195 struct stat sb; 2196 char *path; 2197 2198 if (name != NULL) { 2199 TAILQ_FOREACH(obj, &obj_list, next) { 2200 if (obj->marker) 2201 continue; 2202 if (object_match_name(obj, name)) 2203 return (obj); 2204 } 2205 2206 path = find_library(name, refobj); 2207 if (path == NULL) 2208 return (NULL); 2209 } else 2210 path = NULL; 2211 2212 /* 2213 * If we didn't find a match by pathname, or the name is not 2214 * supplied, open the file and check again by device and inode. 2215 * This avoids false mismatches caused by multiple links or ".." 2216 * in pathnames. 2217 * 2218 * To avoid a race, we open the file and use fstat() rather than 2219 * using stat(). 2220 */ 2221 fd = -1; 2222 if (fd_u == -1) { 2223 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2224 _rtld_error("Cannot open \"%s\"", path); 2225 free(path); 2226 return (NULL); 2227 } 2228 } else { 2229 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2230 if (fd == -1) { 2231 _rtld_error("Cannot dup fd"); 2232 free(path); 2233 return (NULL); 2234 } 2235 } 2236 if (fstat(fd, &sb) == -1) { 2237 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2238 close(fd); 2239 free(path); 2240 return NULL; 2241 } 2242 TAILQ_FOREACH(obj, &obj_list, next) { 2243 if (obj->marker) 2244 continue; 2245 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2246 break; 2247 } 2248 if (obj != NULL && name != NULL) { 2249 object_add_name(obj, name); 2250 free(path); 2251 close(fd); 2252 return obj; 2253 } 2254 if (flags & RTLD_LO_NOLOAD) { 2255 free(path); 2256 close(fd); 2257 return (NULL); 2258 } 2259 2260 /* First use of this object, so we must map it in */ 2261 obj = do_load_object(fd, name, path, &sb, flags); 2262 if (obj == NULL) 2263 free(path); 2264 close(fd); 2265 2266 return obj; 2267} 2268 2269static Obj_Entry * 2270do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2271 int flags) 2272{ 2273 Obj_Entry *obj; 2274 struct statfs fs; 2275 2276 /* 2277 * but first, make sure that environment variables haven't been 2278 * used to circumvent the noexec flag on a filesystem. 2279 */ 2280 if (dangerous_ld_env) { 2281 if (fstatfs(fd, &fs) != 0) { 2282 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2283 return NULL; 2284 } 2285 if (fs.f_flags & MNT_NOEXEC) { 2286 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2287 return NULL; 2288 } 2289 } 2290 dbg("loading \"%s\"", printable_path(path)); 2291 obj = map_object(fd, printable_path(path), sbp); 2292 if (obj == NULL) 2293 return NULL; 2294 2295 /* 2296 * If DT_SONAME is present in the object, digest_dynamic2 already 2297 * added it to the object names. 2298 */ 2299 if (name != NULL) 2300 object_add_name(obj, name); 2301 obj->path = path; 2302 digest_dynamic(obj, 0); 2303 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2304 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2305 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2306 RTLD_LO_DLOPEN) { 2307 dbg("refusing to load non-loadable \"%s\"", obj->path); 2308 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2309 munmap(obj->mapbase, obj->mapsize); 2310 obj_free(obj); 2311 return (NULL); 2312 } 2313 2314 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2315 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2316 obj_count++; 2317 obj_loads++; 2318 linkmap_add(obj); /* for GDB & dlinfo() */ 2319 max_stack_flags |= obj->stack_flags; 2320 2321 dbg(" %p .. %p: %s", obj->mapbase, 2322 obj->mapbase + obj->mapsize - 1, obj->path); 2323 if (obj->textrel) 2324 dbg(" WARNING: %s has impure text", obj->path); 2325 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2326 obj->path); 2327 2328 return obj; 2329} 2330 2331static Obj_Entry * 2332obj_from_addr(const void *addr) 2333{ 2334 Obj_Entry *obj; 2335 2336 TAILQ_FOREACH(obj, &obj_list, next) { 2337 if (obj->marker) 2338 continue; 2339 if (addr < (void *) obj->mapbase) 2340 continue; 2341 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2342 return obj; 2343 } 2344 return NULL; 2345} 2346 2347static void 2348preinit_main(void) 2349{ 2350 Elf_Addr *preinit_addr; 2351 int index; 2352 2353 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2354 if (preinit_addr == NULL) 2355 return; 2356 2357 for (index = 0; index < obj_main->preinit_array_num; index++) { 2358 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2359 dbg("calling preinit function for %s at %p", obj_main->path, 2360 (void *)preinit_addr[index]); 2361 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2362 0, 0, obj_main->path); 2363 call_init_pointer(obj_main, preinit_addr[index]); 2364 } 2365 } 2366} 2367 2368/* 2369 * Call the finalization functions for each of the objects in "list" 2370 * belonging to the DAG of "root" and referenced once. If NULL "root" 2371 * is specified, every finalization function will be called regardless 2372 * of the reference count and the list elements won't be freed. All of 2373 * the objects are expected to have non-NULL fini functions. 2374 */ 2375static void 2376objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2377{ 2378 Objlist_Entry *elm; 2379 char *saved_msg; 2380 Elf_Addr *fini_addr; 2381 int index; 2382 2383 assert(root == NULL || root->refcount == 1); 2384 2385 /* 2386 * Preserve the current error message since a fini function might 2387 * call into the dynamic linker and overwrite it. 2388 */ 2389 saved_msg = errmsg_save(); 2390 do { 2391 STAILQ_FOREACH(elm, list, link) { 2392 if (root != NULL && (elm->obj->refcount != 1 || 2393 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2394 continue; 2395 /* Remove object from fini list to prevent recursive invocation. */ 2396 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2397 /* 2398 * XXX: If a dlopen() call references an object while the 2399 * fini function is in progress, we might end up trying to 2400 * unload the referenced object in dlclose() or the object 2401 * won't be unloaded although its fini function has been 2402 * called. 2403 */ 2404 lock_release(rtld_bind_lock, lockstate); 2405 2406 /* 2407 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2408 * When this happens, DT_FINI_ARRAY is processed first. 2409 */ 2410 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2411 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2412 for (index = elm->obj->fini_array_num - 1; index >= 0; 2413 index--) { 2414 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2415 dbg("calling fini function for %s at %p", 2416 elm->obj->path, (void *)fini_addr[index]); 2417 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2418 (void *)fini_addr[index], 0, 0, elm->obj->path); 2419 call_initfini_pointer(elm->obj, fini_addr[index]); 2420 } 2421 } 2422 } 2423 if (elm->obj->fini != (Elf_Addr)NULL) { 2424 dbg("calling fini function for %s at %p", elm->obj->path, 2425 (void *)elm->obj->fini); 2426 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2427 0, 0, elm->obj->path); 2428 call_initfini_pointer(elm->obj, elm->obj->fini); 2429 } 2430 wlock_acquire(rtld_bind_lock, lockstate); 2431 /* No need to free anything if process is going down. */ 2432 if (root != NULL) 2433 free(elm); 2434 /* 2435 * We must restart the list traversal after every fini call 2436 * because a dlclose() call from the fini function or from 2437 * another thread might have modified the reference counts. 2438 */ 2439 break; 2440 } 2441 } while (elm != NULL); 2442 errmsg_restore(saved_msg); 2443} 2444 2445/* 2446 * Call the initialization functions for each of the objects in 2447 * "list". All of the objects are expected to have non-NULL init 2448 * functions. 2449 */ 2450static void 2451objlist_call_init(Objlist *list, RtldLockState *lockstate) 2452{ 2453 Objlist_Entry *elm; 2454 Obj_Entry *obj; 2455 char *saved_msg; 2456 Elf_Addr *init_addr; 2457 int index; 2458 2459 /* 2460 * Clean init_scanned flag so that objects can be rechecked and 2461 * possibly initialized earlier if any of vectors called below 2462 * cause the change by using dlopen. 2463 */ 2464 TAILQ_FOREACH(obj, &obj_list, next) { 2465 if (obj->marker) 2466 continue; 2467 obj->init_scanned = false; 2468 } 2469 2470 /* 2471 * Preserve the current error message since an init function might 2472 * call into the dynamic linker and overwrite it. 2473 */ 2474 saved_msg = errmsg_save(); 2475 STAILQ_FOREACH(elm, list, link) { 2476 if (elm->obj->init_done) /* Initialized early. */ 2477 continue; 2478 /* 2479 * Race: other thread might try to use this object before current 2480 * one completes the initialization. Not much can be done here 2481 * without better locking. 2482 */ 2483 elm->obj->init_done = true; 2484 lock_release(rtld_bind_lock, lockstate); 2485 2486 /* 2487 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2488 * When this happens, DT_INIT is processed first. 2489 */ 2490 if (elm->obj->init != (Elf_Addr)NULL) { 2491 dbg("calling init function for %s at %p", elm->obj->path, 2492 (void *)elm->obj->init); 2493 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2494 0, 0, elm->obj->path); 2495 call_initfini_pointer(elm->obj, elm->obj->init); 2496 } 2497 init_addr = (Elf_Addr *)elm->obj->init_array; 2498 if (init_addr != NULL) { 2499 for (index = 0; index < elm->obj->init_array_num; index++) { 2500 if (init_addr[index] != 0 && init_addr[index] != 1) { 2501 dbg("calling init function for %s at %p", elm->obj->path, 2502 (void *)init_addr[index]); 2503 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2504 (void *)init_addr[index], 0, 0, elm->obj->path); 2505 call_init_pointer(elm->obj, init_addr[index]); 2506 } 2507 } 2508 } 2509 wlock_acquire(rtld_bind_lock, lockstate); 2510 } 2511 errmsg_restore(saved_msg); 2512} 2513 2514static void 2515objlist_clear(Objlist *list) 2516{ 2517 Objlist_Entry *elm; 2518 2519 while (!STAILQ_EMPTY(list)) { 2520 elm = STAILQ_FIRST(list); 2521 STAILQ_REMOVE_HEAD(list, link); 2522 free(elm); 2523 } 2524} 2525 2526static Objlist_Entry * 2527objlist_find(Objlist *list, const Obj_Entry *obj) 2528{ 2529 Objlist_Entry *elm; 2530 2531 STAILQ_FOREACH(elm, list, link) 2532 if (elm->obj == obj) 2533 return elm; 2534 return NULL; 2535} 2536 2537static void 2538objlist_init(Objlist *list) 2539{ 2540 STAILQ_INIT(list); 2541} 2542 2543static void 2544objlist_push_head(Objlist *list, Obj_Entry *obj) 2545{ 2546 Objlist_Entry *elm; 2547 2548 elm = NEW(Objlist_Entry); 2549 elm->obj = obj; 2550 STAILQ_INSERT_HEAD(list, elm, link); 2551} 2552 2553static void 2554objlist_push_tail(Objlist *list, Obj_Entry *obj) 2555{ 2556 Objlist_Entry *elm; 2557 2558 elm = NEW(Objlist_Entry); 2559 elm->obj = obj; 2560 STAILQ_INSERT_TAIL(list, elm, link); 2561} 2562 2563static void 2564objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2565{ 2566 Objlist_Entry *elm, *listelm; 2567 2568 STAILQ_FOREACH(listelm, list, link) { 2569 if (listelm->obj == listobj) 2570 break; 2571 } 2572 elm = NEW(Objlist_Entry); 2573 elm->obj = obj; 2574 if (listelm != NULL) 2575 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2576 else 2577 STAILQ_INSERT_TAIL(list, elm, link); 2578} 2579 2580static void 2581objlist_remove(Objlist *list, Obj_Entry *obj) 2582{ 2583 Objlist_Entry *elm; 2584 2585 if ((elm = objlist_find(list, obj)) != NULL) { 2586 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2587 free(elm); 2588 } 2589} 2590 2591/* 2592 * Relocate dag rooted in the specified object. 2593 * Returns 0 on success, or -1 on failure. 2594 */ 2595 2596static int 2597relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2598 int flags, RtldLockState *lockstate) 2599{ 2600 Objlist_Entry *elm; 2601 int error; 2602 2603 error = 0; 2604 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2605 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2606 lockstate); 2607 if (error == -1) 2608 break; 2609 } 2610 return (error); 2611} 2612 2613/* 2614 * Prepare for, or clean after, relocating an object marked with 2615 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2616 * segments are remapped read-write. After relocations are done, the 2617 * segment's permissions are returned back to the modes specified in 2618 * the phdrs. If any relocation happened, or always for wired 2619 * program, COW is triggered. 2620 */ 2621static int 2622reloc_textrel_prot(Obj_Entry *obj, bool before) 2623{ 2624 const Elf_Phdr *ph; 2625 void *base; 2626 size_t l, sz; 2627 int prot; 2628 2629 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2630 l--, ph++) { 2631 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2632 continue; 2633 base = obj->relocbase + trunc_page(ph->p_vaddr); 2634 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2635 trunc_page(ph->p_vaddr); 2636 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2637 if (mprotect(base, sz, prot) == -1) { 2638 _rtld_error("%s: Cannot write-%sable text segment: %s", 2639 obj->path, before ? "en" : "dis", 2640 rtld_strerror(errno)); 2641 return (-1); 2642 } 2643 } 2644 return (0); 2645} 2646 2647/* 2648 * Relocate single object. 2649 * Returns 0 on success, or -1 on failure. 2650 */ 2651static int 2652relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2653 int flags, RtldLockState *lockstate) 2654{ 2655 2656 if (obj->relocated) 2657 return (0); 2658 obj->relocated = true; 2659 if (obj != rtldobj) 2660 dbg("relocating \"%s\"", obj->path); 2661 2662 if (obj->symtab == NULL || obj->strtab == NULL || 2663 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2664 _rtld_error("%s: Shared object has no run-time symbol table", 2665 obj->path); 2666 return (-1); 2667 } 2668 2669 /* There are relocations to the write-protected text segment. */ 2670 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2671 return (-1); 2672 2673 /* Process the non-PLT non-IFUNC relocations. */ 2674 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2675 return (-1); 2676 2677 /* Re-protected the text segment. */ 2678 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2679 return (-1); 2680 2681 /* Set the special PLT or GOT entries. */ 2682 init_pltgot(obj); 2683 2684 /* Process the PLT relocations. */ 2685 if (reloc_plt(obj) == -1) 2686 return (-1); 2687 /* Relocate the jump slots if we are doing immediate binding. */ 2688 if (obj->bind_now || bind_now) 2689 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2690 return (-1); 2691 2692 /* 2693 * Process the non-PLT IFUNC relocations. The relocations are 2694 * processed in two phases, because IFUNC resolvers may 2695 * reference other symbols, which must be readily processed 2696 * before resolvers are called. 2697 */ 2698 if (obj->non_plt_gnu_ifunc && 2699 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2700 return (-1); 2701 2702 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2703 return (-1); 2704 2705 /* 2706 * Set up the magic number and version in the Obj_Entry. These 2707 * were checked in the crt1.o from the original ElfKit, so we 2708 * set them for backward compatibility. 2709 */ 2710 obj->magic = RTLD_MAGIC; 2711 obj->version = RTLD_VERSION; 2712 2713 return (0); 2714} 2715 2716/* 2717 * Relocate newly-loaded shared objects. The argument is a pointer to 2718 * the Obj_Entry for the first such object. All objects from the first 2719 * to the end of the list of objects are relocated. Returns 0 on success, 2720 * or -1 on failure. 2721 */ 2722static int 2723relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2724 int flags, RtldLockState *lockstate) 2725{ 2726 Obj_Entry *obj; 2727 int error; 2728 2729 for (error = 0, obj = first; obj != NULL; 2730 obj = TAILQ_NEXT(obj, next)) { 2731 if (obj->marker) 2732 continue; 2733 error = relocate_object(obj, bind_now, rtldobj, flags, 2734 lockstate); 2735 if (error == -1) 2736 break; 2737 } 2738 return (error); 2739} 2740 2741/* 2742 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2743 * referencing STT_GNU_IFUNC symbols is postponed till the other 2744 * relocations are done. The indirect functions specified as 2745 * ifunc are allowed to call other symbols, so we need to have 2746 * objects relocated before asking for resolution from indirects. 2747 * 2748 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2749 * instead of the usual lazy handling of PLT slots. It is 2750 * consistent with how GNU does it. 2751 */ 2752static int 2753resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2754 RtldLockState *lockstate) 2755{ 2756 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2757 return (-1); 2758 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2759 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2760 return (-1); 2761 return (0); 2762} 2763 2764static int 2765resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2766 RtldLockState *lockstate) 2767{ 2768 Obj_Entry *obj; 2769 2770 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2771 if (obj->marker) 2772 continue; 2773 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2774 return (-1); 2775 } 2776 return (0); 2777} 2778 2779static int 2780initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2781 RtldLockState *lockstate) 2782{ 2783 Objlist_Entry *elm; 2784 2785 STAILQ_FOREACH(elm, list, link) { 2786 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2787 lockstate) == -1) 2788 return (-1); 2789 } 2790 return (0); 2791} 2792 2793/* 2794 * Cleanup procedure. It will be called (by the atexit mechanism) just 2795 * before the process exits. 2796 */ 2797static void 2798rtld_exit(void) 2799{ 2800 RtldLockState lockstate; 2801 2802 wlock_acquire(rtld_bind_lock, &lockstate); 2803 dbg("rtld_exit()"); 2804 objlist_call_fini(&list_fini, NULL, &lockstate); 2805 /* No need to remove the items from the list, since we are exiting. */ 2806 if (!libmap_disable) 2807 lm_fini(); 2808 lock_release(rtld_bind_lock, &lockstate); 2809} 2810 2811/* 2812 * Iterate over a search path, translate each element, and invoke the 2813 * callback on the result. 2814 */ 2815static void * 2816path_enumerate(const char *path, path_enum_proc callback, void *arg) 2817{ 2818 const char *trans; 2819 if (path == NULL) 2820 return (NULL); 2821 2822 path += strspn(path, ":;"); 2823 while (*path != '\0') { 2824 size_t len; 2825 char *res; 2826 2827 len = strcspn(path, ":;"); 2828 trans = lm_findn(NULL, path, len); 2829 if (trans) 2830 res = callback(trans, strlen(trans), arg); 2831 else 2832 res = callback(path, len, arg); 2833 2834 if (res != NULL) 2835 return (res); 2836 2837 path += len; 2838 path += strspn(path, ":;"); 2839 } 2840 2841 return (NULL); 2842} 2843 2844struct try_library_args { 2845 const char *name; 2846 size_t namelen; 2847 char *buffer; 2848 size_t buflen; 2849}; 2850 2851static void * 2852try_library_path(const char *dir, size_t dirlen, void *param) 2853{ 2854 struct try_library_args *arg; 2855 2856 arg = param; 2857 if (*dir == '/' || trust) { 2858 char *pathname; 2859 2860 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2861 return (NULL); 2862 2863 pathname = arg->buffer; 2864 strncpy(pathname, dir, dirlen); 2865 pathname[dirlen] = '/'; 2866 strcpy(pathname + dirlen + 1, arg->name); 2867 2868 dbg(" Trying \"%s\"", pathname); 2869 if (access(pathname, F_OK) == 0) { /* We found it */ 2870 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2871 strcpy(pathname, arg->buffer); 2872 return (pathname); 2873 } 2874 } 2875 return (NULL); 2876} 2877 2878static char * 2879search_library_path(const char *name, const char *path) 2880{ 2881 char *p; 2882 struct try_library_args arg; 2883 2884 if (path == NULL) 2885 return NULL; 2886 2887 arg.name = name; 2888 arg.namelen = strlen(name); 2889 arg.buffer = xmalloc(PATH_MAX); 2890 arg.buflen = PATH_MAX; 2891 2892 p = path_enumerate(path, try_library_path, &arg); 2893 2894 free(arg.buffer); 2895 2896 return (p); 2897} 2898 2899int 2900dlclose(void *handle) 2901{ 2902 Obj_Entry *root; 2903 RtldLockState lockstate; 2904 2905 wlock_acquire(rtld_bind_lock, &lockstate); 2906 root = dlcheck(handle); 2907 if (root == NULL) { 2908 lock_release(rtld_bind_lock, &lockstate); 2909 return -1; 2910 } 2911 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2912 root->path); 2913 2914 /* Unreference the object and its dependencies. */ 2915 root->dl_refcount--; 2916 2917 if (root->refcount == 1) { 2918 /* 2919 * The object will be no longer referenced, so we must unload it. 2920 * First, call the fini functions. 2921 */ 2922 objlist_call_fini(&list_fini, root, &lockstate); 2923 2924 unref_dag(root); 2925 2926 /* Finish cleaning up the newly-unreferenced objects. */ 2927 GDB_STATE(RT_DELETE,&root->linkmap); 2928 unload_object(root); 2929 GDB_STATE(RT_CONSISTENT,NULL); 2930 } else 2931 unref_dag(root); 2932 2933 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2934 lock_release(rtld_bind_lock, &lockstate); 2935 return 0; 2936} 2937 2938char * 2939dlerror(void) 2940{ 2941 char *msg = error_message; 2942 error_message = NULL; 2943 return msg; 2944} 2945 2946/* 2947 * This function is deprecated and has no effect. 2948 */ 2949void 2950dllockinit(void *context, 2951 void *(*lock_create)(void *context), 2952 void (*rlock_acquire)(void *lock), 2953 void (*wlock_acquire)(void *lock), 2954 void (*lock_release)(void *lock), 2955 void (*lock_destroy)(void *lock), 2956 void (*context_destroy)(void *context)) 2957{ 2958 static void *cur_context; 2959 static void (*cur_context_destroy)(void *); 2960 2961 /* Just destroy the context from the previous call, if necessary. */ 2962 if (cur_context_destroy != NULL) 2963 cur_context_destroy(cur_context); 2964 cur_context = context; 2965 cur_context_destroy = context_destroy; 2966} 2967 2968void * 2969dlopen(const char *name, int mode) 2970{ 2971 2972 return (rtld_dlopen(name, -1, mode)); 2973} 2974 2975void * 2976fdlopen(int fd, int mode) 2977{ 2978 2979 return (rtld_dlopen(NULL, fd, mode)); 2980} 2981 2982static void * 2983rtld_dlopen(const char *name, int fd, int mode) 2984{ 2985 RtldLockState lockstate; 2986 int lo_flags; 2987 2988 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2989 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2990 if (ld_tracing != NULL) { 2991 rlock_acquire(rtld_bind_lock, &lockstate); 2992 if (sigsetjmp(lockstate.env, 0) != 0) 2993 lock_upgrade(rtld_bind_lock, &lockstate); 2994 environ = (char **)*get_program_var_addr("environ", &lockstate); 2995 lock_release(rtld_bind_lock, &lockstate); 2996 } 2997 lo_flags = RTLD_LO_DLOPEN; 2998 if (mode & RTLD_NODELETE) 2999 lo_flags |= RTLD_LO_NODELETE; 3000 if (mode & RTLD_NOLOAD) 3001 lo_flags |= RTLD_LO_NOLOAD; 3002 if (ld_tracing != NULL) 3003 lo_flags |= RTLD_LO_TRACE; 3004 3005 return (dlopen_object(name, fd, obj_main, lo_flags, 3006 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3007} 3008 3009static void 3010dlopen_cleanup(Obj_Entry *obj) 3011{ 3012 3013 obj->dl_refcount--; 3014 unref_dag(obj); 3015 if (obj->refcount == 0) 3016 unload_object(obj); 3017} 3018 3019static Obj_Entry * 3020dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3021 int mode, RtldLockState *lockstate) 3022{ 3023 Obj_Entry *old_obj_tail; 3024 Obj_Entry *obj; 3025 Objlist initlist; 3026 RtldLockState mlockstate; 3027 int result; 3028 3029 objlist_init(&initlist); 3030 3031 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3032 wlock_acquire(rtld_bind_lock, &mlockstate); 3033 lockstate = &mlockstate; 3034 } 3035 GDB_STATE(RT_ADD,NULL); 3036 3037 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3038 obj = NULL; 3039 if (name == NULL && fd == -1) { 3040 obj = obj_main; 3041 obj->refcount++; 3042 } else { 3043 obj = load_object(name, fd, refobj, lo_flags); 3044 } 3045 3046 if (obj) { 3047 obj->dl_refcount++; 3048 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3049 objlist_push_tail(&list_global, obj); 3050 if (globallist_next(old_obj_tail) != NULL) { 3051 /* We loaded something new. */ 3052 assert(globallist_next(old_obj_tail) == obj); 3053 result = load_needed_objects(obj, 3054 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3055 init_dag(obj); 3056 ref_dag(obj); 3057 if (result != -1) 3058 result = rtld_verify_versions(&obj->dagmembers); 3059 if (result != -1 && ld_tracing) 3060 goto trace; 3061 if (result == -1 || relocate_object_dag(obj, 3062 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3063 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3064 lockstate) == -1) { 3065 dlopen_cleanup(obj); 3066 obj = NULL; 3067 } else if (lo_flags & RTLD_LO_EARLY) { 3068 /* 3069 * Do not call the init functions for early loaded 3070 * filtees. The image is still not initialized enough 3071 * for them to work. 3072 * 3073 * Our object is found by the global object list and 3074 * will be ordered among all init calls done right 3075 * before transferring control to main. 3076 */ 3077 } else { 3078 /* Make list of init functions to call. */ 3079 initlist_add_objects(obj, obj, &initlist); 3080 } 3081 /* 3082 * Process all no_delete or global objects here, given 3083 * them own DAGs to prevent their dependencies from being 3084 * unloaded. This has to be done after we have loaded all 3085 * of the dependencies, so that we do not miss any. 3086 */ 3087 if (obj != NULL) 3088 process_z(obj); 3089 } else { 3090 /* 3091 * Bump the reference counts for objects on this DAG. If 3092 * this is the first dlopen() call for the object that was 3093 * already loaded as a dependency, initialize the dag 3094 * starting at it. 3095 */ 3096 init_dag(obj); 3097 ref_dag(obj); 3098 3099 if ((lo_flags & RTLD_LO_TRACE) != 0) 3100 goto trace; 3101 } 3102 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3103 obj->z_nodelete) && !obj->ref_nodel) { 3104 dbg("obj %s nodelete", obj->path); 3105 ref_dag(obj); 3106 obj->z_nodelete = obj->ref_nodel = true; 3107 } 3108 } 3109 3110 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3111 name); 3112 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3113 3114 if (!(lo_flags & RTLD_LO_EARLY)) { 3115 map_stacks_exec(lockstate); 3116 } 3117 3118 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3119 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3120 lockstate) == -1) { 3121 objlist_clear(&initlist); 3122 dlopen_cleanup(obj); 3123 if (lockstate == &mlockstate) 3124 lock_release(rtld_bind_lock, lockstate); 3125 return (NULL); 3126 } 3127 3128 if (!(lo_flags & RTLD_LO_EARLY)) { 3129 /* Call the init functions. */ 3130 objlist_call_init(&initlist, lockstate); 3131 } 3132 objlist_clear(&initlist); 3133 if (lockstate == &mlockstate) 3134 lock_release(rtld_bind_lock, lockstate); 3135 return obj; 3136trace: 3137 trace_loaded_objects(obj); 3138 if (lockstate == &mlockstate) 3139 lock_release(rtld_bind_lock, lockstate); 3140 exit(0); 3141} 3142 3143static void * 3144do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3145 int flags) 3146{ 3147 DoneList donelist; 3148 const Obj_Entry *obj, *defobj; 3149 const Elf_Sym *def; 3150 SymLook req; 3151 RtldLockState lockstate; 3152#ifndef __ia64__ 3153 tls_index ti; 3154#endif 3155 void *sym; 3156 int res; 3157 3158 def = NULL; 3159 defobj = NULL; 3160 symlook_init(&req, name); 3161 req.ventry = ve; 3162 req.flags = flags | SYMLOOK_IN_PLT; 3163 req.lockstate = &lockstate; 3164 3165 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3166 rlock_acquire(rtld_bind_lock, &lockstate); 3167 if (sigsetjmp(lockstate.env, 0) != 0) 3168 lock_upgrade(rtld_bind_lock, &lockstate); 3169 if (handle == NULL || handle == RTLD_NEXT || 3170 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3171 3172 if ((obj = obj_from_addr(retaddr)) == NULL) { 3173 _rtld_error("Cannot determine caller's shared object"); 3174 lock_release(rtld_bind_lock, &lockstate); 3175 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3176 return NULL; 3177 } 3178 if (handle == NULL) { /* Just the caller's shared object. */ 3179 res = symlook_obj(&req, obj); 3180 if (res == 0) { 3181 def = req.sym_out; 3182 defobj = req.defobj_out; 3183 } 3184 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3185 handle == RTLD_SELF) { /* ... caller included */ 3186 if (handle == RTLD_NEXT) 3187 obj = globallist_next(obj); 3188 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3189 if (obj->marker) 3190 continue; 3191 res = symlook_obj(&req, obj); 3192 if (res == 0) { 3193 if (def == NULL || 3194 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3195 def = req.sym_out; 3196 defobj = req.defobj_out; 3197 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3198 break; 3199 } 3200 } 3201 } 3202 /* 3203 * Search the dynamic linker itself, and possibly resolve the 3204 * symbol from there. This is how the application links to 3205 * dynamic linker services such as dlopen. 3206 */ 3207 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3208 res = symlook_obj(&req, &obj_rtld); 3209 if (res == 0) { 3210 def = req.sym_out; 3211 defobj = req.defobj_out; 3212 } 3213 } 3214 } else { 3215 assert(handle == RTLD_DEFAULT); 3216 res = symlook_default(&req, obj); 3217 if (res == 0) { 3218 defobj = req.defobj_out; 3219 def = req.sym_out; 3220 } 3221 } 3222 } else { 3223 if ((obj = dlcheck(handle)) == NULL) { 3224 lock_release(rtld_bind_lock, &lockstate); 3225 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3226 return NULL; 3227 } 3228 3229 donelist_init(&donelist); 3230 if (obj->mainprog) { 3231 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3232 res = symlook_global(&req, &donelist); 3233 if (res == 0) { 3234 def = req.sym_out; 3235 defobj = req.defobj_out; 3236 } 3237 /* 3238 * Search the dynamic linker itself, and possibly resolve the 3239 * symbol from there. This is how the application links to 3240 * dynamic linker services such as dlopen. 3241 */ 3242 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3243 res = symlook_obj(&req, &obj_rtld); 3244 if (res == 0) { 3245 def = req.sym_out; 3246 defobj = req.defobj_out; 3247 } 3248 } 3249 } 3250 else { 3251 /* Search the whole DAG rooted at the given object. */ 3252 res = symlook_list(&req, &obj->dagmembers, &donelist); 3253 if (res == 0) { 3254 def = req.sym_out; 3255 defobj = req.defobj_out; 3256 } 3257 } 3258 } 3259 3260 if (def != NULL) { 3261 lock_release(rtld_bind_lock, &lockstate); 3262 3263 /* 3264 * The value required by the caller is derived from the value 3265 * of the symbol. For the ia64 architecture, we need to 3266 * construct a function descriptor which the caller can use to 3267 * call the function with the right 'gp' value. For other 3268 * architectures and for non-functions, the value is simply 3269 * the relocated value of the symbol. 3270 */ 3271 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3272 sym = make_function_pointer(def, defobj); 3273 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3274 sym = rtld_resolve_ifunc(defobj, def); 3275 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3276#ifdef __ia64__ 3277 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3278#else 3279 ti.ti_module = defobj->tlsindex; 3280 ti.ti_offset = def->st_value; 3281 sym = __tls_get_addr(&ti); 3282#endif 3283 } else 3284 sym = defobj->relocbase + def->st_value; 3285 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3286 return (sym); 3287 } 3288 3289 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3290 ve != NULL ? ve->name : ""); 3291 lock_release(rtld_bind_lock, &lockstate); 3292 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3293 return NULL; 3294} 3295 3296void * 3297dlsym(void *handle, const char *name) 3298{ 3299 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3300 SYMLOOK_DLSYM); 3301} 3302 3303dlfunc_t 3304dlfunc(void *handle, const char *name) 3305{ 3306 union { 3307 void *d; 3308 dlfunc_t f; 3309 } rv; 3310 3311 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3312 SYMLOOK_DLSYM); 3313 return (rv.f); 3314} 3315 3316void * 3317dlvsym(void *handle, const char *name, const char *version) 3318{ 3319 Ver_Entry ventry; 3320 3321 ventry.name = version; 3322 ventry.file = NULL; 3323 ventry.hash = elf_hash(version); 3324 ventry.flags= 0; 3325 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3326 SYMLOOK_DLSYM); 3327} 3328 3329int 3330_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3331{ 3332 const Obj_Entry *obj; 3333 RtldLockState lockstate; 3334 3335 rlock_acquire(rtld_bind_lock, &lockstate); 3336 obj = obj_from_addr(addr); 3337 if (obj == NULL) { 3338 _rtld_error("No shared object contains address"); 3339 lock_release(rtld_bind_lock, &lockstate); 3340 return (0); 3341 } 3342 rtld_fill_dl_phdr_info(obj, phdr_info); 3343 lock_release(rtld_bind_lock, &lockstate); 3344 return (1); 3345} 3346 3347int 3348dladdr(const void *addr, Dl_info *info) 3349{ 3350 const Obj_Entry *obj; 3351 const Elf_Sym *def; 3352 void *symbol_addr; 3353 unsigned long symoffset; 3354 RtldLockState lockstate; 3355 3356 rlock_acquire(rtld_bind_lock, &lockstate); 3357 obj = obj_from_addr(addr); 3358 if (obj == NULL) { 3359 _rtld_error("No shared object contains address"); 3360 lock_release(rtld_bind_lock, &lockstate); 3361 return 0; 3362 } 3363 info->dli_fname = obj->path; 3364 info->dli_fbase = obj->mapbase; 3365 info->dli_saddr = (void *)0; 3366 info->dli_sname = NULL; 3367 3368 /* 3369 * Walk the symbol list looking for the symbol whose address is 3370 * closest to the address sent in. 3371 */ 3372 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3373 def = obj->symtab + symoffset; 3374 3375 /* 3376 * For skip the symbol if st_shndx is either SHN_UNDEF or 3377 * SHN_COMMON. 3378 */ 3379 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3380 continue; 3381 3382 /* 3383 * If the symbol is greater than the specified address, or if it 3384 * is further away from addr than the current nearest symbol, 3385 * then reject it. 3386 */ 3387 symbol_addr = obj->relocbase + def->st_value; 3388 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3389 continue; 3390 3391 /* Update our idea of the nearest symbol. */ 3392 info->dli_sname = obj->strtab + def->st_name; 3393 info->dli_saddr = symbol_addr; 3394 3395 /* Exact match? */ 3396 if (info->dli_saddr == addr) 3397 break; 3398 } 3399 lock_release(rtld_bind_lock, &lockstate); 3400 return 1; 3401} 3402 3403int 3404dlinfo(void *handle, int request, void *p) 3405{ 3406 const Obj_Entry *obj; 3407 RtldLockState lockstate; 3408 int error; 3409 3410 rlock_acquire(rtld_bind_lock, &lockstate); 3411 3412 if (handle == NULL || handle == RTLD_SELF) { 3413 void *retaddr; 3414 3415 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3416 if ((obj = obj_from_addr(retaddr)) == NULL) 3417 _rtld_error("Cannot determine caller's shared object"); 3418 } else 3419 obj = dlcheck(handle); 3420 3421 if (obj == NULL) { 3422 lock_release(rtld_bind_lock, &lockstate); 3423 return (-1); 3424 } 3425 3426 error = 0; 3427 switch (request) { 3428 case RTLD_DI_LINKMAP: 3429 *((struct link_map const **)p) = &obj->linkmap; 3430 break; 3431 case RTLD_DI_ORIGIN: 3432 error = rtld_dirname(obj->path, p); 3433 break; 3434 3435 case RTLD_DI_SERINFOSIZE: 3436 case RTLD_DI_SERINFO: 3437 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3438 break; 3439 3440 default: 3441 _rtld_error("Invalid request %d passed to dlinfo()", request); 3442 error = -1; 3443 } 3444 3445 lock_release(rtld_bind_lock, &lockstate); 3446 3447 return (error); 3448} 3449 3450static void 3451rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3452{ 3453 3454 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3455 phdr_info->dlpi_name = obj->path; 3456 phdr_info->dlpi_phdr = obj->phdr; 3457 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3458 phdr_info->dlpi_tls_modid = obj->tlsindex; 3459 phdr_info->dlpi_tls_data = obj->tlsinit; 3460 phdr_info->dlpi_adds = obj_loads; 3461 phdr_info->dlpi_subs = obj_loads - obj_count; 3462} 3463 3464int 3465dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3466{ 3467 struct dl_phdr_info phdr_info; 3468 Obj_Entry *obj, marker; 3469 RtldLockState bind_lockstate, phdr_lockstate; 3470 int error; 3471 3472 bzero(&marker, sizeof(marker)); 3473 marker.marker = true; 3474 error = 0; 3475 3476 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3477 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3478 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3479 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3480 rtld_fill_dl_phdr_info(obj, &phdr_info); 3481 lock_release(rtld_bind_lock, &bind_lockstate); 3482 3483 error = callback(&phdr_info, sizeof phdr_info, param); 3484 3485 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3486 obj = globallist_next(&marker); 3487 TAILQ_REMOVE(&obj_list, &marker, next); 3488 if (error != 0) { 3489 lock_release(rtld_bind_lock, &bind_lockstate); 3490 lock_release(rtld_phdr_lock, &phdr_lockstate); 3491 return (error); 3492 } 3493 } 3494 3495 if (error == 0) { 3496 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3497 lock_release(rtld_bind_lock, &bind_lockstate); 3498 error = callback(&phdr_info, sizeof(phdr_info), param); 3499 } 3500 lock_release(rtld_phdr_lock, &phdr_lockstate); 3501 return (error); 3502} 3503 3504static void * 3505fill_search_info(const char *dir, size_t dirlen, void *param) 3506{ 3507 struct fill_search_info_args *arg; 3508 3509 arg = param; 3510 3511 if (arg->request == RTLD_DI_SERINFOSIZE) { 3512 arg->serinfo->dls_cnt ++; 3513 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3514 } else { 3515 struct dl_serpath *s_entry; 3516 3517 s_entry = arg->serpath; 3518 s_entry->dls_name = arg->strspace; 3519 s_entry->dls_flags = arg->flags; 3520 3521 strncpy(arg->strspace, dir, dirlen); 3522 arg->strspace[dirlen] = '\0'; 3523 3524 arg->strspace += dirlen + 1; 3525 arg->serpath++; 3526 } 3527 3528 return (NULL); 3529} 3530 3531static int 3532do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3533{ 3534 struct dl_serinfo _info; 3535 struct fill_search_info_args args; 3536 3537 args.request = RTLD_DI_SERINFOSIZE; 3538 args.serinfo = &_info; 3539 3540 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3541 _info.dls_cnt = 0; 3542 3543 path_enumerate(obj->rpath, fill_search_info, &args); 3544 path_enumerate(ld_library_path, fill_search_info, &args); 3545 path_enumerate(obj->runpath, fill_search_info, &args); 3546 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3547 if (!obj->z_nodeflib) 3548 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3549 3550 3551 if (request == RTLD_DI_SERINFOSIZE) { 3552 info->dls_size = _info.dls_size; 3553 info->dls_cnt = _info.dls_cnt; 3554 return (0); 3555 } 3556 3557 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3558 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3559 return (-1); 3560 } 3561 3562 args.request = RTLD_DI_SERINFO; 3563 args.serinfo = info; 3564 args.serpath = &info->dls_serpath[0]; 3565 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3566 3567 args.flags = LA_SER_RUNPATH; 3568 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3569 return (-1); 3570 3571 args.flags = LA_SER_LIBPATH; 3572 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3573 return (-1); 3574 3575 args.flags = LA_SER_RUNPATH; 3576 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3577 return (-1); 3578 3579 args.flags = LA_SER_CONFIG; 3580 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3581 != NULL) 3582 return (-1); 3583 3584 args.flags = LA_SER_DEFAULT; 3585 if (!obj->z_nodeflib && 3586 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3587 return (-1); 3588 return (0); 3589} 3590 3591static int 3592rtld_dirname(const char *path, char *bname) 3593{ 3594 const char *endp; 3595 3596 /* Empty or NULL string gets treated as "." */ 3597 if (path == NULL || *path == '\0') { 3598 bname[0] = '.'; 3599 bname[1] = '\0'; 3600 return (0); 3601 } 3602 3603 /* Strip trailing slashes */ 3604 endp = path + strlen(path) - 1; 3605 while (endp > path && *endp == '/') 3606 endp--; 3607 3608 /* Find the start of the dir */ 3609 while (endp > path && *endp != '/') 3610 endp--; 3611 3612 /* Either the dir is "/" or there are no slashes */ 3613 if (endp == path) { 3614 bname[0] = *endp == '/' ? '/' : '.'; 3615 bname[1] = '\0'; 3616 return (0); 3617 } else { 3618 do { 3619 endp--; 3620 } while (endp > path && *endp == '/'); 3621 } 3622 3623 if (endp - path + 2 > PATH_MAX) 3624 { 3625 _rtld_error("Filename is too long: %s", path); 3626 return(-1); 3627 } 3628 3629 strncpy(bname, path, endp - path + 1); 3630 bname[endp - path + 1] = '\0'; 3631 return (0); 3632} 3633 3634static int 3635rtld_dirname_abs(const char *path, char *base) 3636{ 3637 char *last; 3638 3639 if (realpath(path, base) == NULL) 3640 return (-1); 3641 dbg("%s -> %s", path, base); 3642 last = strrchr(base, '/'); 3643 if (last == NULL) 3644 return (-1); 3645 if (last != base) 3646 *last = '\0'; 3647 return (0); 3648} 3649 3650static void 3651linkmap_add(Obj_Entry *obj) 3652{ 3653 struct link_map *l = &obj->linkmap; 3654 struct link_map *prev; 3655 3656 obj->linkmap.l_name = obj->path; 3657 obj->linkmap.l_addr = obj->mapbase; 3658 obj->linkmap.l_ld = obj->dynamic; 3659#ifdef __mips__ 3660 /* GDB needs load offset on MIPS to use the symbols */ 3661 obj->linkmap.l_offs = obj->relocbase; 3662#endif 3663 3664 if (r_debug.r_map == NULL) { 3665 r_debug.r_map = l; 3666 return; 3667 } 3668 3669 /* 3670 * Scan to the end of the list, but not past the entry for the 3671 * dynamic linker, which we want to keep at the very end. 3672 */ 3673 for (prev = r_debug.r_map; 3674 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3675 prev = prev->l_next) 3676 ; 3677 3678 /* Link in the new entry. */ 3679 l->l_prev = prev; 3680 l->l_next = prev->l_next; 3681 if (l->l_next != NULL) 3682 l->l_next->l_prev = l; 3683 prev->l_next = l; 3684} 3685 3686static void 3687linkmap_delete(Obj_Entry *obj) 3688{ 3689 struct link_map *l = &obj->linkmap; 3690 3691 if (l->l_prev == NULL) { 3692 if ((r_debug.r_map = l->l_next) != NULL) 3693 l->l_next->l_prev = NULL; 3694 return; 3695 } 3696 3697 if ((l->l_prev->l_next = l->l_next) != NULL) 3698 l->l_next->l_prev = l->l_prev; 3699} 3700 3701/* 3702 * Function for the debugger to set a breakpoint on to gain control. 3703 * 3704 * The two parameters allow the debugger to easily find and determine 3705 * what the runtime loader is doing and to whom it is doing it. 3706 * 3707 * When the loadhook trap is hit (r_debug_state, set at program 3708 * initialization), the arguments can be found on the stack: 3709 * 3710 * +8 struct link_map *m 3711 * +4 struct r_debug *rd 3712 * +0 RetAddr 3713 */ 3714void 3715r_debug_state(struct r_debug* rd, struct link_map *m) 3716{ 3717 /* 3718 * The following is a hack to force the compiler to emit calls to 3719 * this function, even when optimizing. If the function is empty, 3720 * the compiler is not obliged to emit any code for calls to it, 3721 * even when marked __noinline. However, gdb depends on those 3722 * calls being made. 3723 */ 3724 __compiler_membar(); 3725} 3726 3727/* 3728 * A function called after init routines have completed. This can be used to 3729 * break before a program's entry routine is called, and can be used when 3730 * main is not available in the symbol table. 3731 */ 3732void 3733_r_debug_postinit(struct link_map *m) 3734{ 3735 3736 /* See r_debug_state(). */ 3737 __compiler_membar(); 3738} 3739 3740/* 3741 * Get address of the pointer variable in the main program. 3742 * Prefer non-weak symbol over the weak one. 3743 */ 3744static const void ** 3745get_program_var_addr(const char *name, RtldLockState *lockstate) 3746{ 3747 SymLook req; 3748 DoneList donelist; 3749 3750 symlook_init(&req, name); 3751 req.lockstate = lockstate; 3752 donelist_init(&donelist); 3753 if (symlook_global(&req, &donelist) != 0) 3754 return (NULL); 3755 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3756 return ((const void **)make_function_pointer(req.sym_out, 3757 req.defobj_out)); 3758 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3759 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3760 else 3761 return ((const void **)(req.defobj_out->relocbase + 3762 req.sym_out->st_value)); 3763} 3764 3765/* 3766 * Set a pointer variable in the main program to the given value. This 3767 * is used to set key variables such as "environ" before any of the 3768 * init functions are called. 3769 */ 3770static void 3771set_program_var(const char *name, const void *value) 3772{ 3773 const void **addr; 3774 3775 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3776 dbg("\"%s\": *%p <-- %p", name, addr, value); 3777 *addr = value; 3778 } 3779} 3780 3781/* 3782 * Search the global objects, including dependencies and main object, 3783 * for the given symbol. 3784 */ 3785static int 3786symlook_global(SymLook *req, DoneList *donelist) 3787{ 3788 SymLook req1; 3789 const Objlist_Entry *elm; 3790 int res; 3791 3792 symlook_init_from_req(&req1, req); 3793 3794 /* Search all objects loaded at program start up. */ 3795 if (req->defobj_out == NULL || 3796 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3797 res = symlook_list(&req1, &list_main, donelist); 3798 if (res == 0 && (req->defobj_out == NULL || 3799 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3800 req->sym_out = req1.sym_out; 3801 req->defobj_out = req1.defobj_out; 3802 assert(req->defobj_out != NULL); 3803 } 3804 } 3805 3806 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3807 STAILQ_FOREACH(elm, &list_global, link) { 3808 if (req->defobj_out != NULL && 3809 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3810 break; 3811 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3812 if (res == 0 && (req->defobj_out == NULL || 3813 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3814 req->sym_out = req1.sym_out; 3815 req->defobj_out = req1.defobj_out; 3816 assert(req->defobj_out != NULL); 3817 } 3818 } 3819 3820 return (req->sym_out != NULL ? 0 : ESRCH); 3821} 3822 3823/* 3824 * Given a symbol name in a referencing object, find the corresponding 3825 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3826 * no definition was found. Returns a pointer to the Obj_Entry of the 3827 * defining object via the reference parameter DEFOBJ_OUT. 3828 */ 3829static int 3830symlook_default(SymLook *req, const Obj_Entry *refobj) 3831{ 3832 DoneList donelist; 3833 const Objlist_Entry *elm; 3834 SymLook req1; 3835 int res; 3836 3837 donelist_init(&donelist); 3838 symlook_init_from_req(&req1, req); 3839 3840 /* 3841 * Look first in the referencing object if linked symbolically, 3842 * and similarly handle protected symbols. 3843 */ 3844 res = symlook_obj(&req1, refobj); 3845 if (res == 0 && (refobj->symbolic || 3846 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 3847 req->sym_out = req1.sym_out; 3848 req->defobj_out = req1.defobj_out; 3849 assert(req->defobj_out != NULL); 3850 } 3851 if (refobj->symbolic || req->defobj_out != NULL) 3852 donelist_check(&donelist, refobj); 3853 3854 symlook_global(req, &donelist); 3855 3856 /* Search all dlopened DAGs containing the referencing object. */ 3857 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3858 if (req->sym_out != NULL && 3859 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3860 break; 3861 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3862 if (res == 0 && (req->sym_out == NULL || 3863 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3864 req->sym_out = req1.sym_out; 3865 req->defobj_out = req1.defobj_out; 3866 assert(req->defobj_out != NULL); 3867 } 3868 } 3869 3870 /* 3871 * Search the dynamic linker itself, and possibly resolve the 3872 * symbol from there. This is how the application links to 3873 * dynamic linker services such as dlopen. 3874 */ 3875 if (req->sym_out == NULL || 3876 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3877 res = symlook_obj(&req1, &obj_rtld); 3878 if (res == 0) { 3879 req->sym_out = req1.sym_out; 3880 req->defobj_out = req1.defobj_out; 3881 assert(req->defobj_out != NULL); 3882 } 3883 } 3884 3885 return (req->sym_out != NULL ? 0 : ESRCH); 3886} 3887 3888static int 3889symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3890{ 3891 const Elf_Sym *def; 3892 const Obj_Entry *defobj; 3893 const Objlist_Entry *elm; 3894 SymLook req1; 3895 int res; 3896 3897 def = NULL; 3898 defobj = NULL; 3899 STAILQ_FOREACH(elm, objlist, link) { 3900 if (donelist_check(dlp, elm->obj)) 3901 continue; 3902 symlook_init_from_req(&req1, req); 3903 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3904 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3905 def = req1.sym_out; 3906 defobj = req1.defobj_out; 3907 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3908 break; 3909 } 3910 } 3911 } 3912 if (def != NULL) { 3913 req->sym_out = def; 3914 req->defobj_out = defobj; 3915 return (0); 3916 } 3917 return (ESRCH); 3918} 3919 3920/* 3921 * Search the chain of DAGS cointed to by the given Needed_Entry 3922 * for a symbol of the given name. Each DAG is scanned completely 3923 * before advancing to the next one. Returns a pointer to the symbol, 3924 * or NULL if no definition was found. 3925 */ 3926static int 3927symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3928{ 3929 const Elf_Sym *def; 3930 const Needed_Entry *n; 3931 const Obj_Entry *defobj; 3932 SymLook req1; 3933 int res; 3934 3935 def = NULL; 3936 defobj = NULL; 3937 symlook_init_from_req(&req1, req); 3938 for (n = needed; n != NULL; n = n->next) { 3939 if (n->obj == NULL || 3940 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3941 continue; 3942 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3943 def = req1.sym_out; 3944 defobj = req1.defobj_out; 3945 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3946 break; 3947 } 3948 } 3949 if (def != NULL) { 3950 req->sym_out = def; 3951 req->defobj_out = defobj; 3952 return (0); 3953 } 3954 return (ESRCH); 3955} 3956 3957/* 3958 * Search the symbol table of a single shared object for a symbol of 3959 * the given name and version, if requested. Returns a pointer to the 3960 * symbol, or NULL if no definition was found. If the object is 3961 * filter, return filtered symbol from filtee. 3962 * 3963 * The symbol's hash value is passed in for efficiency reasons; that 3964 * eliminates many recomputations of the hash value. 3965 */ 3966int 3967symlook_obj(SymLook *req, const Obj_Entry *obj) 3968{ 3969 DoneList donelist; 3970 SymLook req1; 3971 int flags, res, mres; 3972 3973 /* 3974 * If there is at least one valid hash at this point, we prefer to 3975 * use the faster GNU version if available. 3976 */ 3977 if (obj->valid_hash_gnu) 3978 mres = symlook_obj1_gnu(req, obj); 3979 else if (obj->valid_hash_sysv) 3980 mres = symlook_obj1_sysv(req, obj); 3981 else 3982 return (EINVAL); 3983 3984 if (mres == 0) { 3985 if (obj->needed_filtees != NULL) { 3986 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3987 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3988 donelist_init(&donelist); 3989 symlook_init_from_req(&req1, req); 3990 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3991 if (res == 0) { 3992 req->sym_out = req1.sym_out; 3993 req->defobj_out = req1.defobj_out; 3994 } 3995 return (res); 3996 } 3997 if (obj->needed_aux_filtees != NULL) { 3998 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3999 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4000 donelist_init(&donelist); 4001 symlook_init_from_req(&req1, req); 4002 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4003 if (res == 0) { 4004 req->sym_out = req1.sym_out; 4005 req->defobj_out = req1.defobj_out; 4006 return (res); 4007 } 4008 } 4009 } 4010 return (mres); 4011} 4012 4013/* Symbol match routine common to both hash functions */ 4014static bool 4015matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4016 const unsigned long symnum) 4017{ 4018 Elf_Versym verndx; 4019 const Elf_Sym *symp; 4020 const char *strp; 4021 4022 symp = obj->symtab + symnum; 4023 strp = obj->strtab + symp->st_name; 4024 4025 switch (ELF_ST_TYPE(symp->st_info)) { 4026 case STT_FUNC: 4027 case STT_NOTYPE: 4028 case STT_OBJECT: 4029 case STT_COMMON: 4030 case STT_GNU_IFUNC: 4031 if (symp->st_value == 0) 4032 return (false); 4033 /* fallthrough */ 4034 case STT_TLS: 4035 if (symp->st_shndx != SHN_UNDEF) 4036 break; 4037#ifndef __mips__ 4038 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4039 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4040 break; 4041 /* fallthrough */ 4042#endif 4043 default: 4044 return (false); 4045 } 4046 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4047 return (false); 4048 4049 if (req->ventry == NULL) { 4050 if (obj->versyms != NULL) { 4051 verndx = VER_NDX(obj->versyms[symnum]); 4052 if (verndx > obj->vernum) { 4053 _rtld_error( 4054 "%s: symbol %s references wrong version %d", 4055 obj->path, obj->strtab + symnum, verndx); 4056 return (false); 4057 } 4058 /* 4059 * If we are not called from dlsym (i.e. this 4060 * is a normal relocation from unversioned 4061 * binary), accept the symbol immediately if 4062 * it happens to have first version after this 4063 * shared object became versioned. Otherwise, 4064 * if symbol is versioned and not hidden, 4065 * remember it. If it is the only symbol with 4066 * this name exported by the shared object, it 4067 * will be returned as a match by the calling 4068 * function. If symbol is global (verndx < 2) 4069 * accept it unconditionally. 4070 */ 4071 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4072 verndx == VER_NDX_GIVEN) { 4073 result->sym_out = symp; 4074 return (true); 4075 } 4076 else if (verndx >= VER_NDX_GIVEN) { 4077 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4078 == 0) { 4079 if (result->vsymp == NULL) 4080 result->vsymp = symp; 4081 result->vcount++; 4082 } 4083 return (false); 4084 } 4085 } 4086 result->sym_out = symp; 4087 return (true); 4088 } 4089 if (obj->versyms == NULL) { 4090 if (object_match_name(obj, req->ventry->name)) { 4091 _rtld_error("%s: object %s should provide version %s " 4092 "for symbol %s", obj_rtld.path, obj->path, 4093 req->ventry->name, obj->strtab + symnum); 4094 return (false); 4095 } 4096 } else { 4097 verndx = VER_NDX(obj->versyms[symnum]); 4098 if (verndx > obj->vernum) { 4099 _rtld_error("%s: symbol %s references wrong version %d", 4100 obj->path, obj->strtab + symnum, verndx); 4101 return (false); 4102 } 4103 if (obj->vertab[verndx].hash != req->ventry->hash || 4104 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4105 /* 4106 * Version does not match. Look if this is a 4107 * global symbol and if it is not hidden. If 4108 * global symbol (verndx < 2) is available, 4109 * use it. Do not return symbol if we are 4110 * called by dlvsym, because dlvsym looks for 4111 * a specific version and default one is not 4112 * what dlvsym wants. 4113 */ 4114 if ((req->flags & SYMLOOK_DLSYM) || 4115 (verndx >= VER_NDX_GIVEN) || 4116 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4117 return (false); 4118 } 4119 } 4120 result->sym_out = symp; 4121 return (true); 4122} 4123 4124/* 4125 * Search for symbol using SysV hash function. 4126 * obj->buckets is known not to be NULL at this point; the test for this was 4127 * performed with the obj->valid_hash_sysv assignment. 4128 */ 4129static int 4130symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4131{ 4132 unsigned long symnum; 4133 Sym_Match_Result matchres; 4134 4135 matchres.sym_out = NULL; 4136 matchres.vsymp = NULL; 4137 matchres.vcount = 0; 4138 4139 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4140 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4141 if (symnum >= obj->nchains) 4142 return (ESRCH); /* Bad object */ 4143 4144 if (matched_symbol(req, obj, &matchres, symnum)) { 4145 req->sym_out = matchres.sym_out; 4146 req->defobj_out = obj; 4147 return (0); 4148 } 4149 } 4150 if (matchres.vcount == 1) { 4151 req->sym_out = matchres.vsymp; 4152 req->defobj_out = obj; 4153 return (0); 4154 } 4155 return (ESRCH); 4156} 4157 4158/* Search for symbol using GNU hash function */ 4159static int 4160symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4161{ 4162 Elf_Addr bloom_word; 4163 const Elf32_Word *hashval; 4164 Elf32_Word bucket; 4165 Sym_Match_Result matchres; 4166 unsigned int h1, h2; 4167 unsigned long symnum; 4168 4169 matchres.sym_out = NULL; 4170 matchres.vsymp = NULL; 4171 matchres.vcount = 0; 4172 4173 /* Pick right bitmask word from Bloom filter array */ 4174 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4175 obj->maskwords_bm_gnu]; 4176 4177 /* Calculate modulus word size of gnu hash and its derivative */ 4178 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4179 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4180 4181 /* Filter out the "definitely not in set" queries */ 4182 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4183 return (ESRCH); 4184 4185 /* Locate hash chain and corresponding value element*/ 4186 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4187 if (bucket == 0) 4188 return (ESRCH); 4189 hashval = &obj->chain_zero_gnu[bucket]; 4190 do { 4191 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4192 symnum = hashval - obj->chain_zero_gnu; 4193 if (matched_symbol(req, obj, &matchres, symnum)) { 4194 req->sym_out = matchres.sym_out; 4195 req->defobj_out = obj; 4196 return (0); 4197 } 4198 } 4199 } while ((*hashval++ & 1) == 0); 4200 if (matchres.vcount == 1) { 4201 req->sym_out = matchres.vsymp; 4202 req->defobj_out = obj; 4203 return (0); 4204 } 4205 return (ESRCH); 4206} 4207 4208static void 4209trace_loaded_objects(Obj_Entry *obj) 4210{ 4211 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4212 int c; 4213 4214 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4215 main_local = ""; 4216 4217 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4218 fmt1 = "\t%o => %p (%x)\n"; 4219 4220 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4221 fmt2 = "\t%o (%x)\n"; 4222 4223 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4224 4225 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4226 Needed_Entry *needed; 4227 char *name, *path; 4228 bool is_lib; 4229 4230 if (obj->marker) 4231 continue; 4232 if (list_containers && obj->needed != NULL) 4233 rtld_printf("%s:\n", obj->path); 4234 for (needed = obj->needed; needed; needed = needed->next) { 4235 if (needed->obj != NULL) { 4236 if (needed->obj->traced && !list_containers) 4237 continue; 4238 needed->obj->traced = true; 4239 path = needed->obj->path; 4240 } else 4241 path = "not found"; 4242 4243 name = (char *)obj->strtab + needed->name; 4244 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4245 4246 fmt = is_lib ? fmt1 : fmt2; 4247 while ((c = *fmt++) != '\0') { 4248 switch (c) { 4249 default: 4250 rtld_putchar(c); 4251 continue; 4252 case '\\': 4253 switch (c = *fmt) { 4254 case '\0': 4255 continue; 4256 case 'n': 4257 rtld_putchar('\n'); 4258 break; 4259 case 't': 4260 rtld_putchar('\t'); 4261 break; 4262 } 4263 break; 4264 case '%': 4265 switch (c = *fmt) { 4266 case '\0': 4267 continue; 4268 case '%': 4269 default: 4270 rtld_putchar(c); 4271 break; 4272 case 'A': 4273 rtld_putstr(main_local); 4274 break; 4275 case 'a': 4276 rtld_putstr(obj_main->path); 4277 break; 4278 case 'o': 4279 rtld_putstr(name); 4280 break; 4281#if 0 4282 case 'm': 4283 rtld_printf("%d", sodp->sod_major); 4284 break; 4285 case 'n': 4286 rtld_printf("%d", sodp->sod_minor); 4287 break; 4288#endif 4289 case 'p': 4290 rtld_putstr(path); 4291 break; 4292 case 'x': 4293 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4294 0); 4295 break; 4296 } 4297 break; 4298 } 4299 ++fmt; 4300 } 4301 } 4302 } 4303} 4304 4305/* 4306 * Unload a dlopened object and its dependencies from memory and from 4307 * our data structures. It is assumed that the DAG rooted in the 4308 * object has already been unreferenced, and that the object has a 4309 * reference count of 0. 4310 */ 4311static void 4312unload_object(Obj_Entry *root) 4313{ 4314 Obj_Entry *obj, *obj1; 4315 4316 assert(root->refcount == 0); 4317 4318 /* 4319 * Pass over the DAG removing unreferenced objects from 4320 * appropriate lists. 4321 */ 4322 unlink_object(root); 4323 4324 /* Unmap all objects that are no longer referenced. */ 4325 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4326 if (obj->marker || obj->refcount != 0) 4327 continue; 4328 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4329 obj->mapsize, 0, obj->path); 4330 dbg("unloading \"%s\"", obj->path); 4331 unload_filtees(root); 4332 munmap(obj->mapbase, obj->mapsize); 4333 linkmap_delete(obj); 4334 TAILQ_REMOVE(&obj_list, obj, next); 4335 obj_count--; 4336 obj_free(obj); 4337 } 4338} 4339 4340static void 4341unlink_object(Obj_Entry *root) 4342{ 4343 Objlist_Entry *elm; 4344 4345 if (root->refcount == 0) { 4346 /* Remove the object from the RTLD_GLOBAL list. */ 4347 objlist_remove(&list_global, root); 4348 4349 /* Remove the object from all objects' DAG lists. */ 4350 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4351 objlist_remove(&elm->obj->dldags, root); 4352 if (elm->obj != root) 4353 unlink_object(elm->obj); 4354 } 4355 } 4356} 4357 4358static void 4359ref_dag(Obj_Entry *root) 4360{ 4361 Objlist_Entry *elm; 4362 4363 assert(root->dag_inited); 4364 STAILQ_FOREACH(elm, &root->dagmembers, link) 4365 elm->obj->refcount++; 4366} 4367 4368static void 4369unref_dag(Obj_Entry *root) 4370{ 4371 Objlist_Entry *elm; 4372 4373 assert(root->dag_inited); 4374 STAILQ_FOREACH(elm, &root->dagmembers, link) 4375 elm->obj->refcount--; 4376} 4377 4378/* 4379 * Common code for MD __tls_get_addr(). 4380 */ 4381static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4382static void * 4383tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4384{ 4385 Elf_Addr *newdtv, *dtv; 4386 RtldLockState lockstate; 4387 int to_copy; 4388 4389 dtv = *dtvp; 4390 /* Check dtv generation in case new modules have arrived */ 4391 if (dtv[0] != tls_dtv_generation) { 4392 wlock_acquire(rtld_bind_lock, &lockstate); 4393 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4394 to_copy = dtv[1]; 4395 if (to_copy > tls_max_index) 4396 to_copy = tls_max_index; 4397 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4398 newdtv[0] = tls_dtv_generation; 4399 newdtv[1] = tls_max_index; 4400 free(dtv); 4401 lock_release(rtld_bind_lock, &lockstate); 4402 dtv = *dtvp = newdtv; 4403 } 4404 4405 /* Dynamically allocate module TLS if necessary */ 4406 if (dtv[index + 1] == 0) { 4407 /* Signal safe, wlock will block out signals. */ 4408 wlock_acquire(rtld_bind_lock, &lockstate); 4409 if (!dtv[index + 1]) 4410 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4411 lock_release(rtld_bind_lock, &lockstate); 4412 } 4413 return ((void *)(dtv[index + 1] + offset)); 4414} 4415 4416void * 4417tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4418{ 4419 Elf_Addr *dtv; 4420 4421 dtv = *dtvp; 4422 /* Check dtv generation in case new modules have arrived */ 4423 if (__predict_true(dtv[0] == tls_dtv_generation && 4424 dtv[index + 1] != 0)) 4425 return ((void *)(dtv[index + 1] + offset)); 4426 return (tls_get_addr_slow(dtvp, index, offset)); 4427} 4428 4429#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4430 4431/* 4432 * Allocate Static TLS using the Variant I method. 4433 */ 4434void * 4435allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4436{ 4437 Obj_Entry *obj; 4438 char *tcb; 4439 Elf_Addr **tls; 4440 Elf_Addr *dtv; 4441 Elf_Addr addr; 4442 int i; 4443 4444 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4445 return (oldtcb); 4446 4447 assert(tcbsize >= TLS_TCB_SIZE); 4448 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4449 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4450 4451 if (oldtcb != NULL) { 4452 memcpy(tls, oldtcb, tls_static_space); 4453 free(oldtcb); 4454 4455 /* Adjust the DTV. */ 4456 dtv = tls[0]; 4457 for (i = 0; i < dtv[1]; i++) { 4458 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4459 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4460 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4461 } 4462 } 4463 } else { 4464 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4465 tls[0] = dtv; 4466 dtv[0] = tls_dtv_generation; 4467 dtv[1] = tls_max_index; 4468 4469 for (obj = globallist_curr(objs); obj != NULL; 4470 obj = globallist_next(obj)) { 4471 if (obj->tlsoffset > 0) { 4472 addr = (Elf_Addr)tls + obj->tlsoffset; 4473 if (obj->tlsinitsize > 0) 4474 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4475 if (obj->tlssize > obj->tlsinitsize) 4476 memset((void*) (addr + obj->tlsinitsize), 0, 4477 obj->tlssize - obj->tlsinitsize); 4478 dtv[obj->tlsindex + 1] = addr; 4479 } 4480 } 4481 } 4482 4483 return (tcb); 4484} 4485 4486void 4487free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4488{ 4489 Elf_Addr *dtv; 4490 Elf_Addr tlsstart, tlsend; 4491 int dtvsize, i; 4492 4493 assert(tcbsize >= TLS_TCB_SIZE); 4494 4495 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4496 tlsend = tlsstart + tls_static_space; 4497 4498 dtv = *(Elf_Addr **)tlsstart; 4499 dtvsize = dtv[1]; 4500 for (i = 0; i < dtvsize; i++) { 4501 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4502 free((void*)dtv[i+2]); 4503 } 4504 } 4505 free(dtv); 4506 free(tcb); 4507} 4508 4509#endif 4510 4511#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4512 4513/* 4514 * Allocate Static TLS using the Variant II method. 4515 */ 4516void * 4517allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4518{ 4519 Obj_Entry *obj; 4520 size_t size, ralign; 4521 char *tls; 4522 Elf_Addr *dtv, *olddtv; 4523 Elf_Addr segbase, oldsegbase, addr; 4524 int i; 4525 4526 ralign = tcbalign; 4527 if (tls_static_max_align > ralign) 4528 ralign = tls_static_max_align; 4529 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4530 4531 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4532 tls = malloc_aligned(size, ralign); 4533 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4534 4535 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4536 ((Elf_Addr*)segbase)[0] = segbase; 4537 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4538 4539 dtv[0] = tls_dtv_generation; 4540 dtv[1] = tls_max_index; 4541 4542 if (oldtls) { 4543 /* 4544 * Copy the static TLS block over whole. 4545 */ 4546 oldsegbase = (Elf_Addr) oldtls; 4547 memcpy((void *)(segbase - tls_static_space), 4548 (const void *)(oldsegbase - tls_static_space), 4549 tls_static_space); 4550 4551 /* 4552 * If any dynamic TLS blocks have been created tls_get_addr(), 4553 * move them over. 4554 */ 4555 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4556 for (i = 0; i < olddtv[1]; i++) { 4557 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4558 dtv[i+2] = olddtv[i+2]; 4559 olddtv[i+2] = 0; 4560 } 4561 } 4562 4563 /* 4564 * We assume that this block was the one we created with 4565 * allocate_initial_tls(). 4566 */ 4567 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4568 } else { 4569 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4570 if (obj->marker || obj->tlsoffset == 0) 4571 continue; 4572 addr = segbase - obj->tlsoffset; 4573 memset((void*) (addr + obj->tlsinitsize), 4574 0, obj->tlssize - obj->tlsinitsize); 4575 if (obj->tlsinit) 4576 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4577 dtv[obj->tlsindex + 1] = addr; 4578 } 4579 } 4580 4581 return (void*) segbase; 4582} 4583 4584void 4585free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4586{ 4587 Elf_Addr* dtv; 4588 size_t size, ralign; 4589 int dtvsize, i; 4590 Elf_Addr tlsstart, tlsend; 4591 4592 /* 4593 * Figure out the size of the initial TLS block so that we can 4594 * find stuff which ___tls_get_addr() allocated dynamically. 4595 */ 4596 ralign = tcbalign; 4597 if (tls_static_max_align > ralign) 4598 ralign = tls_static_max_align; 4599 size = round(tls_static_space, ralign); 4600 4601 dtv = ((Elf_Addr**)tls)[1]; 4602 dtvsize = dtv[1]; 4603 tlsend = (Elf_Addr) tls; 4604 tlsstart = tlsend - size; 4605 for (i = 0; i < dtvsize; i++) { 4606 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4607 free_aligned((void *)dtv[i + 2]); 4608 } 4609 } 4610 4611 free_aligned((void *)tlsstart); 4612 free((void*) dtv); 4613} 4614 4615#endif 4616 4617/* 4618 * Allocate TLS block for module with given index. 4619 */ 4620void * 4621allocate_module_tls(int index) 4622{ 4623 Obj_Entry* obj; 4624 char* p; 4625 4626 TAILQ_FOREACH(obj, &obj_list, next) { 4627 if (obj->marker) 4628 continue; 4629 if (obj->tlsindex == index) 4630 break; 4631 } 4632 if (!obj) { 4633 _rtld_error("Can't find module with TLS index %d", index); 4634 rtld_die(); 4635 } 4636 4637 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4638 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4639 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4640 4641 return p; 4642} 4643 4644bool 4645allocate_tls_offset(Obj_Entry *obj) 4646{ 4647 size_t off; 4648 4649 if (obj->tls_done) 4650 return true; 4651 4652 if (obj->tlssize == 0) { 4653 obj->tls_done = true; 4654 return true; 4655 } 4656 4657 if (tls_last_offset == 0) 4658 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4659 else 4660 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4661 obj->tlssize, obj->tlsalign); 4662 4663 /* 4664 * If we have already fixed the size of the static TLS block, we 4665 * must stay within that size. When allocating the static TLS, we 4666 * leave a small amount of space spare to be used for dynamically 4667 * loading modules which use static TLS. 4668 */ 4669 if (tls_static_space != 0) { 4670 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4671 return false; 4672 } else if (obj->tlsalign > tls_static_max_align) { 4673 tls_static_max_align = obj->tlsalign; 4674 } 4675 4676 tls_last_offset = obj->tlsoffset = off; 4677 tls_last_size = obj->tlssize; 4678 obj->tls_done = true; 4679 4680 return true; 4681} 4682 4683void 4684free_tls_offset(Obj_Entry *obj) 4685{ 4686 4687 /* 4688 * If we were the last thing to allocate out of the static TLS 4689 * block, we give our space back to the 'allocator'. This is a 4690 * simplistic workaround to allow libGL.so.1 to be loaded and 4691 * unloaded multiple times. 4692 */ 4693 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4694 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4695 tls_last_offset -= obj->tlssize; 4696 tls_last_size = 0; 4697 } 4698} 4699 4700void * 4701_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4702{ 4703 void *ret; 4704 RtldLockState lockstate; 4705 4706 wlock_acquire(rtld_bind_lock, &lockstate); 4707 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4708 tcbsize, tcbalign); 4709 lock_release(rtld_bind_lock, &lockstate); 4710 return (ret); 4711} 4712 4713void 4714_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4715{ 4716 RtldLockState lockstate; 4717 4718 wlock_acquire(rtld_bind_lock, &lockstate); 4719 free_tls(tcb, tcbsize, tcbalign); 4720 lock_release(rtld_bind_lock, &lockstate); 4721} 4722 4723static void 4724object_add_name(Obj_Entry *obj, const char *name) 4725{ 4726 Name_Entry *entry; 4727 size_t len; 4728 4729 len = strlen(name); 4730 entry = malloc(sizeof(Name_Entry) + len); 4731 4732 if (entry != NULL) { 4733 strcpy(entry->name, name); 4734 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4735 } 4736} 4737 4738static int 4739object_match_name(const Obj_Entry *obj, const char *name) 4740{ 4741 Name_Entry *entry; 4742 4743 STAILQ_FOREACH(entry, &obj->names, link) { 4744 if (strcmp(name, entry->name) == 0) 4745 return (1); 4746 } 4747 return (0); 4748} 4749 4750static Obj_Entry * 4751locate_dependency(const Obj_Entry *obj, const char *name) 4752{ 4753 const Objlist_Entry *entry; 4754 const Needed_Entry *needed; 4755 4756 STAILQ_FOREACH(entry, &list_main, link) { 4757 if (object_match_name(entry->obj, name)) 4758 return entry->obj; 4759 } 4760 4761 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4762 if (strcmp(obj->strtab + needed->name, name) == 0 || 4763 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4764 /* 4765 * If there is DT_NEEDED for the name we are looking for, 4766 * we are all set. Note that object might not be found if 4767 * dependency was not loaded yet, so the function can 4768 * return NULL here. This is expected and handled 4769 * properly by the caller. 4770 */ 4771 return (needed->obj); 4772 } 4773 } 4774 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4775 obj->path, name); 4776 rtld_die(); 4777} 4778 4779static int 4780check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4781 const Elf_Vernaux *vna) 4782{ 4783 const Elf_Verdef *vd; 4784 const char *vername; 4785 4786 vername = refobj->strtab + vna->vna_name; 4787 vd = depobj->verdef; 4788 if (vd == NULL) { 4789 _rtld_error("%s: version %s required by %s not defined", 4790 depobj->path, vername, refobj->path); 4791 return (-1); 4792 } 4793 for (;;) { 4794 if (vd->vd_version != VER_DEF_CURRENT) { 4795 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4796 depobj->path, vd->vd_version); 4797 return (-1); 4798 } 4799 if (vna->vna_hash == vd->vd_hash) { 4800 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4801 ((char *)vd + vd->vd_aux); 4802 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4803 return (0); 4804 } 4805 if (vd->vd_next == 0) 4806 break; 4807 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4808 } 4809 if (vna->vna_flags & VER_FLG_WEAK) 4810 return (0); 4811 _rtld_error("%s: version %s required by %s not found", 4812 depobj->path, vername, refobj->path); 4813 return (-1); 4814} 4815 4816static int 4817rtld_verify_object_versions(Obj_Entry *obj) 4818{ 4819 const Elf_Verneed *vn; 4820 const Elf_Verdef *vd; 4821 const Elf_Verdaux *vda; 4822 const Elf_Vernaux *vna; 4823 const Obj_Entry *depobj; 4824 int maxvernum, vernum; 4825 4826 if (obj->ver_checked) 4827 return (0); 4828 obj->ver_checked = true; 4829 4830 maxvernum = 0; 4831 /* 4832 * Walk over defined and required version records and figure out 4833 * max index used by any of them. Do very basic sanity checking 4834 * while there. 4835 */ 4836 vn = obj->verneed; 4837 while (vn != NULL) { 4838 if (vn->vn_version != VER_NEED_CURRENT) { 4839 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4840 obj->path, vn->vn_version); 4841 return (-1); 4842 } 4843 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4844 for (;;) { 4845 vernum = VER_NEED_IDX(vna->vna_other); 4846 if (vernum > maxvernum) 4847 maxvernum = vernum; 4848 if (vna->vna_next == 0) 4849 break; 4850 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4851 } 4852 if (vn->vn_next == 0) 4853 break; 4854 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4855 } 4856 4857 vd = obj->verdef; 4858 while (vd != NULL) { 4859 if (vd->vd_version != VER_DEF_CURRENT) { 4860 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4861 obj->path, vd->vd_version); 4862 return (-1); 4863 } 4864 vernum = VER_DEF_IDX(vd->vd_ndx); 4865 if (vernum > maxvernum) 4866 maxvernum = vernum; 4867 if (vd->vd_next == 0) 4868 break; 4869 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4870 } 4871 4872 if (maxvernum == 0) 4873 return (0); 4874 4875 /* 4876 * Store version information in array indexable by version index. 4877 * Verify that object version requirements are satisfied along the 4878 * way. 4879 */ 4880 obj->vernum = maxvernum + 1; 4881 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4882 4883 vd = obj->verdef; 4884 while (vd != NULL) { 4885 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4886 vernum = VER_DEF_IDX(vd->vd_ndx); 4887 assert(vernum <= maxvernum); 4888 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4889 obj->vertab[vernum].hash = vd->vd_hash; 4890 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4891 obj->vertab[vernum].file = NULL; 4892 obj->vertab[vernum].flags = 0; 4893 } 4894 if (vd->vd_next == 0) 4895 break; 4896 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4897 } 4898 4899 vn = obj->verneed; 4900 while (vn != NULL) { 4901 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4902 if (depobj == NULL) 4903 return (-1); 4904 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4905 for (;;) { 4906 if (check_object_provided_version(obj, depobj, vna)) 4907 return (-1); 4908 vernum = VER_NEED_IDX(vna->vna_other); 4909 assert(vernum <= maxvernum); 4910 obj->vertab[vernum].hash = vna->vna_hash; 4911 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4912 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4913 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4914 VER_INFO_HIDDEN : 0; 4915 if (vna->vna_next == 0) 4916 break; 4917 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4918 } 4919 if (vn->vn_next == 0) 4920 break; 4921 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4922 } 4923 return 0; 4924} 4925 4926static int 4927rtld_verify_versions(const Objlist *objlist) 4928{ 4929 Objlist_Entry *entry; 4930 int rc; 4931 4932 rc = 0; 4933 STAILQ_FOREACH(entry, objlist, link) { 4934 /* 4935 * Skip dummy objects or objects that have their version requirements 4936 * already checked. 4937 */ 4938 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4939 continue; 4940 if (rtld_verify_object_versions(entry->obj) == -1) { 4941 rc = -1; 4942 if (ld_tracing == NULL) 4943 break; 4944 } 4945 } 4946 if (rc == 0 || ld_tracing != NULL) 4947 rc = rtld_verify_object_versions(&obj_rtld); 4948 return rc; 4949} 4950 4951const Ver_Entry * 4952fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4953{ 4954 Elf_Versym vernum; 4955 4956 if (obj->vertab) { 4957 vernum = VER_NDX(obj->versyms[symnum]); 4958 if (vernum >= obj->vernum) { 4959 _rtld_error("%s: symbol %s has wrong verneed value %d", 4960 obj->path, obj->strtab + symnum, vernum); 4961 } else if (obj->vertab[vernum].hash != 0) { 4962 return &obj->vertab[vernum]; 4963 } 4964 } 4965 return NULL; 4966} 4967 4968int 4969_rtld_get_stack_prot(void) 4970{ 4971 4972 return (stack_prot); 4973} 4974 4975int 4976_rtld_is_dlopened(void *arg) 4977{ 4978 Obj_Entry *obj; 4979 RtldLockState lockstate; 4980 int res; 4981 4982 rlock_acquire(rtld_bind_lock, &lockstate); 4983 obj = dlcheck(arg); 4984 if (obj == NULL) 4985 obj = obj_from_addr(arg); 4986 if (obj == NULL) { 4987 _rtld_error("No shared object contains address"); 4988 lock_release(rtld_bind_lock, &lockstate); 4989 return (-1); 4990 } 4991 res = obj->dlopened ? 1 : 0; 4992 lock_release(rtld_bind_lock, &lockstate); 4993 return (res); 4994} 4995 4996int 4997obj_enforce_relro(Obj_Entry *obj) 4998{ 4999 5000 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5001 PROT_READ) == -1) { 5002 _rtld_error("%s: Cannot enforce relro protection: %s", 5003 obj->path, rtld_strerror(errno)); 5004 return (-1); 5005 } 5006 return (0); 5007} 5008 5009static void 5010map_stacks_exec(RtldLockState *lockstate) 5011{ 5012 void (*thr_map_stacks_exec)(void); 5013 5014 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5015 return; 5016 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5017 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5018 if (thr_map_stacks_exec != NULL) { 5019 stack_prot |= PROT_EXEC; 5020 thr_map_stacks_exec(); 5021 } 5022} 5023 5024void 5025symlook_init(SymLook *dst, const char *name) 5026{ 5027 5028 bzero(dst, sizeof(*dst)); 5029 dst->name = name; 5030 dst->hash = elf_hash(name); 5031 dst->hash_gnu = gnu_hash(name); 5032} 5033 5034static void 5035symlook_init_from_req(SymLook *dst, const SymLook *src) 5036{ 5037 5038 dst->name = src->name; 5039 dst->hash = src->hash; 5040 dst->hash_gnu = src->hash_gnu; 5041 dst->ventry = src->ventry; 5042 dst->flags = src->flags; 5043 dst->defobj_out = NULL; 5044 dst->sym_out = NULL; 5045 dst->lockstate = src->lockstate; 5046} 5047 5048/* 5049 * Overrides for libc_pic-provided functions. 5050 */ 5051 5052int 5053__getosreldate(void) 5054{ 5055 size_t len; 5056 int oid[2]; 5057 int error, osrel; 5058 5059 if (osreldate != 0) 5060 return (osreldate); 5061 5062 oid[0] = CTL_KERN; 5063 oid[1] = KERN_OSRELDATE; 5064 osrel = 0; 5065 len = sizeof(osrel); 5066 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5067 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5068 osreldate = osrel; 5069 return (osreldate); 5070} 5071 5072void 5073exit(int status) 5074{ 5075 5076 _exit(status); 5077} 5078 5079void (*__cleanup)(void); 5080int __isthreaded = 0; 5081int _thread_autoinit_dummy_decl = 1; 5082 5083/* 5084 * No unresolved symbols for rtld. 5085 */ 5086void 5087__pthread_cxa_finalize(struct dl_phdr_info *a) 5088{ 5089} 5090 5091void 5092__stack_chk_fail(void) 5093{ 5094 5095 _rtld_error("stack overflow detected; terminated"); 5096 rtld_die(); 5097} 5098__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5099 5100void 5101__chk_fail(void) 5102{ 5103 5104 _rtld_error("buffer overflow detected; terminated"); 5105 rtld_die(); 5106} 5107 5108const char * 5109rtld_strerror(int errnum) 5110{ 5111 5112 if (errnum < 0 || errnum >= sys_nerr) 5113 return ("Unknown error"); 5114 return (sys_errlist[errnum]); 5115} 5116