rtld.c revision 331206
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 331206 2018-03-19 14:28:58Z marius $ 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 /* 663 * Execute MD initializers required before we call the objects' 664 * init functions. 665 */ 666 pre_init(); 667 668 wlock_acquire(rtld_bind_lock, &lockstate); 669 if (obj_main->crt_no_init) 670 preinit_main(); 671 objlist_call_init(&initlist, &lockstate); 672 _r_debug_postinit(&obj_main->linkmap); 673 objlist_clear(&initlist); 674 dbg("loading filtees"); 675 TAILQ_FOREACH(obj, &obj_list, next) { 676 if (obj->marker) 677 continue; 678 if (ld_loadfltr || obj->z_loadfltr) 679 load_filtees(obj, 0, &lockstate); 680 } 681 lock_release(rtld_bind_lock, &lockstate); 682 683 dbg("transferring control to program entry point = %p", obj_main->entry); 684 685 /* Return the exit procedure and the program entry point. */ 686 *exit_proc = rtld_exit; 687 *objp = obj_main; 688 return (func_ptr_type) obj_main->entry; 689} 690 691void * 692rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 693{ 694 void *ptr; 695 Elf_Addr target; 696 697 ptr = (void *)make_function_pointer(def, obj); 698 target = call_ifunc_resolver(ptr); 699 return ((void *)target); 700} 701 702Elf_Addr 703_rtld_bind(Obj_Entry *obj, Elf_Size reloff) 704{ 705 const Elf_Rel *rel; 706 const Elf_Sym *def; 707 const Obj_Entry *defobj; 708 Elf_Addr *where; 709 Elf_Addr target; 710 RtldLockState lockstate; 711 712 rlock_acquire(rtld_bind_lock, &lockstate); 713 if (sigsetjmp(lockstate.env, 0) != 0) 714 lock_upgrade(rtld_bind_lock, &lockstate); 715 if (obj->pltrel) 716 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 717 else 718 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 719 720 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 721 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, 722 NULL, &lockstate); 723 if (def == NULL) 724 rtld_die(); 725 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 726 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 727 else 728 target = (Elf_Addr)(defobj->relocbase + def->st_value); 729 730 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 731 defobj->strtab + def->st_name, basename(obj->path), 732 (void *)target, basename(defobj->path)); 733 734 /* 735 * Write the new contents for the jmpslot. Note that depending on 736 * architecture, the value which we need to return back to the 737 * lazy binding trampoline may or may not be the target 738 * address. The value returned from reloc_jmpslot() is the value 739 * that the trampoline needs. 740 */ 741 target = reloc_jmpslot(where, target, defobj, obj, rel); 742 lock_release(rtld_bind_lock, &lockstate); 743 return target; 744} 745 746/* 747 * Error reporting function. Use it like printf. If formats the message 748 * into a buffer, and sets things up so that the next call to dlerror() 749 * will return the message. 750 */ 751void 752_rtld_error(const char *fmt, ...) 753{ 754 static char buf[512]; 755 va_list ap; 756 757 va_start(ap, fmt); 758 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 759 error_message = buf; 760 va_end(ap); 761} 762 763/* 764 * Return a dynamically-allocated copy of the current error message, if any. 765 */ 766static char * 767errmsg_save(void) 768{ 769 return error_message == NULL ? NULL : xstrdup(error_message); 770} 771 772/* 773 * Restore the current error message from a copy which was previously saved 774 * by errmsg_save(). The copy is freed. 775 */ 776static void 777errmsg_restore(char *saved_msg) 778{ 779 if (saved_msg == NULL) 780 error_message = NULL; 781 else { 782 _rtld_error("%s", saved_msg); 783 free(saved_msg); 784 } 785} 786 787static const char * 788basename(const char *name) 789{ 790 const char *p = strrchr(name, '/'); 791 return p != NULL ? p + 1 : name; 792} 793 794static struct utsname uts; 795 796static char * 797origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 798 const char *subst, bool may_free) 799{ 800 char *p, *p1, *res, *resp; 801 int subst_len, kw_len, subst_count, old_len, new_len; 802 803 kw_len = strlen(kw); 804 805 /* 806 * First, count the number of the keyword occurences, to 807 * preallocate the final string. 808 */ 809 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 810 p1 = strstr(p, kw); 811 if (p1 == NULL) 812 break; 813 } 814 815 /* 816 * If the keyword is not found, just return. 817 * 818 * Return non-substituted string if resolution failed. We 819 * cannot do anything more reasonable, the failure mode of the 820 * caller is unresolved library anyway. 821 */ 822 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 823 return (may_free ? real : xstrdup(real)); 824 if (obj != NULL) 825 subst = obj->origin_path; 826 827 /* 828 * There is indeed something to substitute. Calculate the 829 * length of the resulting string, and allocate it. 830 */ 831 subst_len = strlen(subst); 832 old_len = strlen(real); 833 new_len = old_len + (subst_len - kw_len) * subst_count; 834 res = xmalloc(new_len + 1); 835 836 /* 837 * Now, execute the substitution loop. 838 */ 839 for (p = real, resp = res, *resp = '\0';;) { 840 p1 = strstr(p, kw); 841 if (p1 != NULL) { 842 /* Copy the prefix before keyword. */ 843 memcpy(resp, p, p1 - p); 844 resp += p1 - p; 845 /* Keyword replacement. */ 846 memcpy(resp, subst, subst_len); 847 resp += subst_len; 848 *resp = '\0'; 849 p = p1 + kw_len; 850 } else 851 break; 852 } 853 854 /* Copy to the end of string and finish. */ 855 strcat(resp, p); 856 if (may_free) 857 free(real); 858 return (res); 859} 860 861static char * 862origin_subst(Obj_Entry *obj, char *real) 863{ 864 char *res1, *res2, *res3, *res4; 865 866 if (obj == NULL || !trust) 867 return (xstrdup(real)); 868 if (uts.sysname[0] == '\0') { 869 if (uname(&uts) != 0) { 870 _rtld_error("utsname failed: %d", errno); 871 return (NULL); 872 } 873 } 874 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 875 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 876 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 877 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 878 return (res4); 879} 880 881void 882rtld_die(void) 883{ 884 const char *msg = dlerror(); 885 886 if (msg == NULL) 887 msg = "Fatal error"; 888 rtld_fdputstr(STDERR_FILENO, msg); 889 rtld_fdputchar(STDERR_FILENO, '\n'); 890 _exit(1); 891} 892 893/* 894 * Process a shared object's DYNAMIC section, and save the important 895 * information in its Obj_Entry structure. 896 */ 897static void 898digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 899 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 900{ 901 const Elf_Dyn *dynp; 902 Needed_Entry **needed_tail = &obj->needed; 903 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 904 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 905 const Elf_Hashelt *hashtab; 906 const Elf32_Word *hashval; 907 Elf32_Word bkt, nmaskwords; 908 int bloom_size32; 909 int plttype = DT_REL; 910 911 *dyn_rpath = NULL; 912 *dyn_soname = NULL; 913 *dyn_runpath = NULL; 914 915 obj->bind_now = false; 916 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 917 switch (dynp->d_tag) { 918 919 case DT_REL: 920 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 921 break; 922 923 case DT_RELSZ: 924 obj->relsize = dynp->d_un.d_val; 925 break; 926 927 case DT_RELENT: 928 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 929 break; 930 931 case DT_JMPREL: 932 obj->pltrel = (const Elf_Rel *) 933 (obj->relocbase + dynp->d_un.d_ptr); 934 break; 935 936 case DT_PLTRELSZ: 937 obj->pltrelsize = dynp->d_un.d_val; 938 break; 939 940 case DT_RELA: 941 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 942 break; 943 944 case DT_RELASZ: 945 obj->relasize = dynp->d_un.d_val; 946 break; 947 948 case DT_RELAENT: 949 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 950 break; 951 952 case DT_PLTREL: 953 plttype = dynp->d_un.d_val; 954 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 955 break; 956 957 case DT_SYMTAB: 958 obj->symtab = (const Elf_Sym *) 959 (obj->relocbase + dynp->d_un.d_ptr); 960 break; 961 962 case DT_SYMENT: 963 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 964 break; 965 966 case DT_STRTAB: 967 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 968 break; 969 970 case DT_STRSZ: 971 obj->strsize = dynp->d_un.d_val; 972 break; 973 974 case DT_VERNEED: 975 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 976 dynp->d_un.d_val); 977 break; 978 979 case DT_VERNEEDNUM: 980 obj->verneednum = dynp->d_un.d_val; 981 break; 982 983 case DT_VERDEF: 984 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 985 dynp->d_un.d_val); 986 break; 987 988 case DT_VERDEFNUM: 989 obj->verdefnum = dynp->d_un.d_val; 990 break; 991 992 case DT_VERSYM: 993 obj->versyms = (const Elf_Versym *)(obj->relocbase + 994 dynp->d_un.d_val); 995 break; 996 997 case DT_HASH: 998 { 999 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1000 dynp->d_un.d_ptr); 1001 obj->nbuckets = hashtab[0]; 1002 obj->nchains = hashtab[1]; 1003 obj->buckets = hashtab + 2; 1004 obj->chains = obj->buckets + obj->nbuckets; 1005 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1006 obj->buckets != NULL; 1007 } 1008 break; 1009 1010 case DT_GNU_HASH: 1011 { 1012 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1013 dynp->d_un.d_ptr); 1014 obj->nbuckets_gnu = hashtab[0]; 1015 obj->symndx_gnu = hashtab[1]; 1016 nmaskwords = hashtab[2]; 1017 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1018 obj->maskwords_bm_gnu = nmaskwords - 1; 1019 obj->shift2_gnu = hashtab[3]; 1020 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1021 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1022 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1023 obj->symndx_gnu; 1024 /* Number of bitmask words is required to be power of 2 */ 1025 obj->valid_hash_gnu = powerof2(nmaskwords) && 1026 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1027 } 1028 break; 1029 1030 case DT_NEEDED: 1031 if (!obj->rtld) { 1032 Needed_Entry *nep = NEW(Needed_Entry); 1033 nep->name = dynp->d_un.d_val; 1034 nep->obj = NULL; 1035 nep->next = NULL; 1036 1037 *needed_tail = nep; 1038 needed_tail = &nep->next; 1039 } 1040 break; 1041 1042 case DT_FILTER: 1043 if (!obj->rtld) { 1044 Needed_Entry *nep = NEW(Needed_Entry); 1045 nep->name = dynp->d_un.d_val; 1046 nep->obj = NULL; 1047 nep->next = NULL; 1048 1049 *needed_filtees_tail = nep; 1050 needed_filtees_tail = &nep->next; 1051 } 1052 break; 1053 1054 case DT_AUXILIARY: 1055 if (!obj->rtld) { 1056 Needed_Entry *nep = NEW(Needed_Entry); 1057 nep->name = dynp->d_un.d_val; 1058 nep->obj = NULL; 1059 nep->next = NULL; 1060 1061 *needed_aux_filtees_tail = nep; 1062 needed_aux_filtees_tail = &nep->next; 1063 } 1064 break; 1065 1066 case DT_PLTGOT: 1067 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1068 break; 1069 1070 case DT_TEXTREL: 1071 obj->textrel = true; 1072 break; 1073 1074 case DT_SYMBOLIC: 1075 obj->symbolic = true; 1076 break; 1077 1078 case DT_RPATH: 1079 /* 1080 * We have to wait until later to process this, because we 1081 * might not have gotten the address of the string table yet. 1082 */ 1083 *dyn_rpath = dynp; 1084 break; 1085 1086 case DT_SONAME: 1087 *dyn_soname = dynp; 1088 break; 1089 1090 case DT_RUNPATH: 1091 *dyn_runpath = dynp; 1092 break; 1093 1094 case DT_INIT: 1095 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1096 break; 1097 1098 case DT_PREINIT_ARRAY: 1099 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1100 break; 1101 1102 case DT_PREINIT_ARRAYSZ: 1103 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1104 break; 1105 1106 case DT_INIT_ARRAY: 1107 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1108 break; 1109 1110 case DT_INIT_ARRAYSZ: 1111 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1112 break; 1113 1114 case DT_FINI: 1115 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1116 break; 1117 1118 case DT_FINI_ARRAY: 1119 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1120 break; 1121 1122 case DT_FINI_ARRAYSZ: 1123 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1124 break; 1125 1126 /* 1127 * Don't process DT_DEBUG on MIPS as the dynamic section 1128 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1129 */ 1130 1131#ifndef __mips__ 1132 case DT_DEBUG: 1133 if (!early) 1134 dbg("Filling in DT_DEBUG entry"); 1135 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1136 break; 1137#endif 1138 1139 case DT_FLAGS: 1140 if (dynp->d_un.d_val & DF_ORIGIN) 1141 obj->z_origin = true; 1142 if (dynp->d_un.d_val & DF_SYMBOLIC) 1143 obj->symbolic = true; 1144 if (dynp->d_un.d_val & DF_TEXTREL) 1145 obj->textrel = true; 1146 if (dynp->d_un.d_val & DF_BIND_NOW) 1147 obj->bind_now = true; 1148 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1149 ;*/ 1150 break; 1151#ifdef __mips__ 1152 case DT_MIPS_LOCAL_GOTNO: 1153 obj->local_gotno = dynp->d_un.d_val; 1154 break; 1155 1156 case DT_MIPS_SYMTABNO: 1157 obj->symtabno = dynp->d_un.d_val; 1158 break; 1159 1160 case DT_MIPS_GOTSYM: 1161 obj->gotsym = dynp->d_un.d_val; 1162 break; 1163 1164 case DT_MIPS_RLD_MAP: 1165 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1166 break; 1167#endif 1168 1169 case DT_FLAGS_1: 1170 if (dynp->d_un.d_val & DF_1_NOOPEN) 1171 obj->z_noopen = true; 1172 if (dynp->d_un.d_val & DF_1_ORIGIN) 1173 obj->z_origin = true; 1174 if (dynp->d_un.d_val & DF_1_GLOBAL) 1175 obj->z_global = true; 1176 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1177 obj->bind_now = true; 1178 if (dynp->d_un.d_val & DF_1_NODELETE) 1179 obj->z_nodelete = true; 1180 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1181 obj->z_loadfltr = true; 1182 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1183 obj->z_interpose = true; 1184 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1185 obj->z_nodeflib = true; 1186 break; 1187 1188 default: 1189 if (!early) { 1190 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1191 (long)dynp->d_tag); 1192 } 1193 break; 1194 } 1195 } 1196 1197 obj->traced = false; 1198 1199 if (plttype == DT_RELA) { 1200 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1201 obj->pltrel = NULL; 1202 obj->pltrelasize = obj->pltrelsize; 1203 obj->pltrelsize = 0; 1204 } 1205 1206 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1207 if (obj->valid_hash_sysv) 1208 obj->dynsymcount = obj->nchains; 1209 else if (obj->valid_hash_gnu) { 1210 obj->dynsymcount = 0; 1211 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1212 if (obj->buckets_gnu[bkt] == 0) 1213 continue; 1214 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1215 do 1216 obj->dynsymcount++; 1217 while ((*hashval++ & 1u) == 0); 1218 } 1219 obj->dynsymcount += obj->symndx_gnu; 1220 } 1221} 1222 1223static bool 1224obj_resolve_origin(Obj_Entry *obj) 1225{ 1226 1227 if (obj->origin_path != NULL) 1228 return (true); 1229 obj->origin_path = xmalloc(PATH_MAX); 1230 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1231} 1232 1233static void 1234digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1235 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1236{ 1237 1238 if (obj->z_origin && !obj_resolve_origin(obj)) 1239 rtld_die(); 1240 1241 if (dyn_runpath != NULL) { 1242 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1243 obj->runpath = origin_subst(obj, obj->runpath); 1244 } else if (dyn_rpath != NULL) { 1245 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1246 obj->rpath = origin_subst(obj, obj->rpath); 1247 } 1248 if (dyn_soname != NULL) 1249 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1250} 1251 1252static void 1253digest_dynamic(Obj_Entry *obj, int early) 1254{ 1255 const Elf_Dyn *dyn_rpath; 1256 const Elf_Dyn *dyn_soname; 1257 const Elf_Dyn *dyn_runpath; 1258 1259 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1260 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1261} 1262 1263/* 1264 * Process a shared object's program header. This is used only for the 1265 * main program, when the kernel has already loaded the main program 1266 * into memory before calling the dynamic linker. It creates and 1267 * returns an Obj_Entry structure. 1268 */ 1269static Obj_Entry * 1270digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1271{ 1272 Obj_Entry *obj; 1273 const Elf_Phdr *phlimit = phdr + phnum; 1274 const Elf_Phdr *ph; 1275 Elf_Addr note_start, note_end; 1276 int nsegs = 0; 1277 1278 obj = obj_new(); 1279 for (ph = phdr; ph < phlimit; ph++) { 1280 if (ph->p_type != PT_PHDR) 1281 continue; 1282 1283 obj->phdr = phdr; 1284 obj->phsize = ph->p_memsz; 1285 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1286 break; 1287 } 1288 1289 obj->stack_flags = PF_X | PF_R | PF_W; 1290 1291 for (ph = phdr; ph < phlimit; ph++) { 1292 switch (ph->p_type) { 1293 1294 case PT_INTERP: 1295 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1296 break; 1297 1298 case PT_LOAD: 1299 if (nsegs == 0) { /* First load segment */ 1300 obj->vaddrbase = trunc_page(ph->p_vaddr); 1301 obj->mapbase = obj->vaddrbase + obj->relocbase; 1302 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1303 obj->vaddrbase; 1304 } else { /* Last load segment */ 1305 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1306 obj->vaddrbase; 1307 } 1308 nsegs++; 1309 break; 1310 1311 case PT_DYNAMIC: 1312 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1313 break; 1314 1315 case PT_TLS: 1316 obj->tlsindex = 1; 1317 obj->tlssize = ph->p_memsz; 1318 obj->tlsalign = ph->p_align; 1319 obj->tlsinitsize = ph->p_filesz; 1320 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1321 break; 1322 1323 case PT_GNU_STACK: 1324 obj->stack_flags = ph->p_flags; 1325 break; 1326 1327 case PT_GNU_RELRO: 1328 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1329 obj->relro_size = round_page(ph->p_memsz); 1330 break; 1331 1332 case PT_NOTE: 1333 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1334 note_end = note_start + ph->p_filesz; 1335 digest_notes(obj, note_start, note_end); 1336 break; 1337 } 1338 } 1339 if (nsegs < 1) { 1340 _rtld_error("%s: too few PT_LOAD segments", path); 1341 return NULL; 1342 } 1343 1344 obj->entry = entry; 1345 return obj; 1346} 1347 1348void 1349digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1350{ 1351 const Elf_Note *note; 1352 const char *note_name; 1353 uintptr_t p; 1354 1355 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1356 note = (const Elf_Note *)((const char *)(note + 1) + 1357 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1358 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1359 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1360 note->n_descsz != sizeof(int32_t)) 1361 continue; 1362 if (note->n_type != ABI_NOTETYPE && 1363 note->n_type != CRT_NOINIT_NOTETYPE) 1364 continue; 1365 note_name = (const char *)(note + 1); 1366 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1367 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1368 continue; 1369 switch (note->n_type) { 1370 case ABI_NOTETYPE: 1371 /* FreeBSD osrel note */ 1372 p = (uintptr_t)(note + 1); 1373 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1374 obj->osrel = *(const int32_t *)(p); 1375 dbg("note osrel %d", obj->osrel); 1376 break; 1377 case CRT_NOINIT_NOTETYPE: 1378 /* FreeBSD 'crt does not call init' note */ 1379 obj->crt_no_init = true; 1380 dbg("note crt_no_init"); 1381 break; 1382 } 1383 } 1384} 1385 1386static Obj_Entry * 1387dlcheck(void *handle) 1388{ 1389 Obj_Entry *obj; 1390 1391 TAILQ_FOREACH(obj, &obj_list, next) { 1392 if (obj == (Obj_Entry *) handle) 1393 break; 1394 } 1395 1396 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1397 _rtld_error("Invalid shared object handle %p", handle); 1398 return NULL; 1399 } 1400 return obj; 1401} 1402 1403/* 1404 * If the given object is already in the donelist, return true. Otherwise 1405 * add the object to the list and return false. 1406 */ 1407static bool 1408donelist_check(DoneList *dlp, const Obj_Entry *obj) 1409{ 1410 unsigned int i; 1411 1412 for (i = 0; i < dlp->num_used; i++) 1413 if (dlp->objs[i] == obj) 1414 return true; 1415 /* 1416 * Our donelist allocation should always be sufficient. But if 1417 * our threads locking isn't working properly, more shared objects 1418 * could have been loaded since we allocated the list. That should 1419 * never happen, but we'll handle it properly just in case it does. 1420 */ 1421 if (dlp->num_used < dlp->num_alloc) 1422 dlp->objs[dlp->num_used++] = obj; 1423 return false; 1424} 1425 1426/* 1427 * Hash function for symbol table lookup. Don't even think about changing 1428 * this. It is specified by the System V ABI. 1429 */ 1430unsigned long 1431elf_hash(const char *name) 1432{ 1433 const unsigned char *p = (const unsigned char *) name; 1434 unsigned long h = 0; 1435 unsigned long g; 1436 1437 while (*p != '\0') { 1438 h = (h << 4) + *p++; 1439 if ((g = h & 0xf0000000) != 0) 1440 h ^= g >> 24; 1441 h &= ~g; 1442 } 1443 return h; 1444} 1445 1446/* 1447 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1448 * unsigned in case it's implemented with a wider type. 1449 */ 1450static uint32_t 1451gnu_hash(const char *s) 1452{ 1453 uint32_t h; 1454 unsigned char c; 1455 1456 h = 5381; 1457 for (c = *s; c != '\0'; c = *++s) 1458 h = h * 33 + c; 1459 return (h & 0xffffffff); 1460} 1461 1462/* 1463 * Find the library with the given name, and return its full pathname. 1464 * The returned string is dynamically allocated. Generates an error 1465 * message and returns NULL if the library cannot be found. 1466 * 1467 * If the second argument is non-NULL, then it refers to an already- 1468 * loaded shared object, whose library search path will be searched. 1469 * 1470 * The search order is: 1471 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1472 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1473 * LD_LIBRARY_PATH 1474 * DT_RUNPATH in the referencing file 1475 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1476 * from list) 1477 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1478 * 1479 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1480 */ 1481static char * 1482find_library(const char *xname, const Obj_Entry *refobj) 1483{ 1484 char *pathname; 1485 char *name; 1486 bool nodeflib, objgiven; 1487 1488 objgiven = refobj != NULL; 1489 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1490 if (xname[0] != '/' && !trust) { 1491 _rtld_error("Absolute pathname required for shared object \"%s\"", 1492 xname); 1493 return NULL; 1494 } 1495 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1496 __DECONST(char *, xname))); 1497 } 1498 1499 if (libmap_disable || !objgiven || 1500 (name = lm_find(refobj->path, xname)) == NULL) 1501 name = (char *)xname; 1502 1503 dbg(" Searching for \"%s\"", name); 1504 1505 /* 1506 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1507 * back to pre-conforming behaviour if user requested so with 1508 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1509 * nodeflib. 1510 */ 1511 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1512 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1513 (refobj != NULL && 1514 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1515 (pathname = search_library_path(name, gethints(false))) != NULL || 1516 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1517 return (pathname); 1518 } else { 1519 nodeflib = objgiven ? refobj->z_nodeflib : false; 1520 if ((objgiven && 1521 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1522 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1523 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1524 (pathname = search_library_path(name, ld_library_path)) != NULL || 1525 (objgiven && 1526 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1527 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1528 (objgiven && !nodeflib && 1529 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1530 return (pathname); 1531 } 1532 1533 if (objgiven && refobj->path != NULL) { 1534 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1535 name, basename(refobj->path)); 1536 } else { 1537 _rtld_error("Shared object \"%s\" not found", name); 1538 } 1539 return NULL; 1540} 1541 1542/* 1543 * Given a symbol number in a referencing object, find the corresponding 1544 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1545 * no definition was found. Returns a pointer to the Obj_Entry of the 1546 * defining object via the reference parameter DEFOBJ_OUT. 1547 */ 1548const Elf_Sym * 1549find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1550 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1551 RtldLockState *lockstate) 1552{ 1553 const Elf_Sym *ref; 1554 const Elf_Sym *def; 1555 const Obj_Entry *defobj; 1556 const Ver_Entry *ve; 1557 SymLook req; 1558 const char *name; 1559 int res; 1560 1561 /* 1562 * If we have already found this symbol, get the information from 1563 * the cache. 1564 */ 1565 if (symnum >= refobj->dynsymcount) 1566 return NULL; /* Bad object */ 1567 if (cache != NULL && cache[symnum].sym != NULL) { 1568 *defobj_out = cache[symnum].obj; 1569 return cache[symnum].sym; 1570 } 1571 1572 ref = refobj->symtab + symnum; 1573 name = refobj->strtab + ref->st_name; 1574 def = NULL; 1575 defobj = NULL; 1576 ve = NULL; 1577 1578 /* 1579 * We don't have to do a full scale lookup if the symbol is local. 1580 * We know it will bind to the instance in this load module; to 1581 * which we already have a pointer (ie ref). By not doing a lookup, 1582 * we not only improve performance, but it also avoids unresolvable 1583 * symbols when local symbols are not in the hash table. This has 1584 * been seen with the ia64 toolchain. 1585 */ 1586 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1587 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1588 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1589 symnum); 1590 } 1591 symlook_init(&req, name); 1592 req.flags = flags; 1593 ve = req.ventry = fetch_ventry(refobj, symnum); 1594 req.lockstate = lockstate; 1595 res = symlook_default(&req, refobj); 1596 if (res == 0) { 1597 def = req.sym_out; 1598 defobj = req.defobj_out; 1599 } 1600 } else { 1601 def = ref; 1602 defobj = refobj; 1603 } 1604 1605 /* 1606 * If we found no definition and the reference is weak, treat the 1607 * symbol as having the value zero. 1608 */ 1609 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1610 def = &sym_zero; 1611 defobj = obj_main; 1612 } 1613 1614 if (def != NULL) { 1615 *defobj_out = defobj; 1616 /* Record the information in the cache to avoid subsequent lookups. */ 1617 if (cache != NULL) { 1618 cache[symnum].sym = def; 1619 cache[symnum].obj = defobj; 1620 } 1621 } else { 1622 if (refobj != &obj_rtld) 1623 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, 1624 ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); 1625 } 1626 return def; 1627} 1628 1629/* 1630 * Return the search path from the ldconfig hints file, reading it if 1631 * necessary. If nostdlib is true, then the default search paths are 1632 * not added to result. 1633 * 1634 * Returns NULL if there are problems with the hints file, 1635 * or if the search path there is empty. 1636 */ 1637static const char * 1638gethints(bool nostdlib) 1639{ 1640 static char *hints, *filtered_path; 1641 static struct elfhints_hdr hdr; 1642 struct fill_search_info_args sargs, hargs; 1643 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1644 struct dl_serpath *SLPpath, *hintpath; 1645 char *p; 1646 struct stat hint_stat; 1647 unsigned int SLPndx, hintndx, fndx, fcount; 1648 int fd; 1649 size_t flen; 1650 uint32_t dl; 1651 bool skip; 1652 1653 /* First call, read the hints file */ 1654 if (hints == NULL) { 1655 /* Keep from trying again in case the hints file is bad. */ 1656 hints = ""; 1657 1658 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1659 return (NULL); 1660 1661 /* 1662 * Check of hdr.dirlistlen value against type limit 1663 * intends to pacify static analyzers. Further 1664 * paranoia leads to checks that dirlist is fully 1665 * contained in the file range. 1666 */ 1667 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1668 hdr.magic != ELFHINTS_MAGIC || 1669 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 || 1670 fstat(fd, &hint_stat) == -1) { 1671cleanup1: 1672 close(fd); 1673 hdr.dirlistlen = 0; 1674 return (NULL); 1675 } 1676 dl = hdr.strtab; 1677 if (dl + hdr.dirlist < dl) 1678 goto cleanup1; 1679 dl += hdr.dirlist; 1680 if (dl + hdr.dirlistlen < dl) 1681 goto cleanup1; 1682 dl += hdr.dirlistlen; 1683 if (dl > hint_stat.st_size) 1684 goto cleanup1; 1685 p = xmalloc(hdr.dirlistlen + 1); 1686 1687 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1688 read(fd, p, hdr.dirlistlen + 1) != 1689 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') { 1690 free(p); 1691 goto cleanup1; 1692 } 1693 hints = p; 1694 close(fd); 1695 } 1696 1697 /* 1698 * If caller agreed to receive list which includes the default 1699 * paths, we are done. Otherwise, if we still did not 1700 * calculated filtered result, do it now. 1701 */ 1702 if (!nostdlib) 1703 return (hints[0] != '\0' ? hints : NULL); 1704 if (filtered_path != NULL) 1705 goto filt_ret; 1706 1707 /* 1708 * Obtain the list of all configured search paths, and the 1709 * list of the default paths. 1710 * 1711 * First estimate the size of the results. 1712 */ 1713 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1714 smeta.dls_cnt = 0; 1715 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1716 hmeta.dls_cnt = 0; 1717 1718 sargs.request = RTLD_DI_SERINFOSIZE; 1719 sargs.serinfo = &smeta; 1720 hargs.request = RTLD_DI_SERINFOSIZE; 1721 hargs.serinfo = &hmeta; 1722 1723 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1724 path_enumerate(hints, fill_search_info, &hargs); 1725 1726 SLPinfo = xmalloc(smeta.dls_size); 1727 hintinfo = xmalloc(hmeta.dls_size); 1728 1729 /* 1730 * Next fetch both sets of paths. 1731 */ 1732 sargs.request = RTLD_DI_SERINFO; 1733 sargs.serinfo = SLPinfo; 1734 sargs.serpath = &SLPinfo->dls_serpath[0]; 1735 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1736 1737 hargs.request = RTLD_DI_SERINFO; 1738 hargs.serinfo = hintinfo; 1739 hargs.serpath = &hintinfo->dls_serpath[0]; 1740 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1741 1742 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1743 path_enumerate(hints, fill_search_info, &hargs); 1744 1745 /* 1746 * Now calculate the difference between two sets, by excluding 1747 * standard paths from the full set. 1748 */ 1749 fndx = 0; 1750 fcount = 0; 1751 filtered_path = xmalloc(hdr.dirlistlen + 1); 1752 hintpath = &hintinfo->dls_serpath[0]; 1753 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1754 skip = false; 1755 SLPpath = &SLPinfo->dls_serpath[0]; 1756 /* 1757 * Check each standard path against current. 1758 */ 1759 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1760 /* matched, skip the path */ 1761 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1762 skip = true; 1763 break; 1764 } 1765 } 1766 if (skip) 1767 continue; 1768 /* 1769 * Not matched against any standard path, add the path 1770 * to result. Separate consequtive paths with ':'. 1771 */ 1772 if (fcount > 0) { 1773 filtered_path[fndx] = ':'; 1774 fndx++; 1775 } 1776 fcount++; 1777 flen = strlen(hintpath->dls_name); 1778 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1779 fndx += flen; 1780 } 1781 filtered_path[fndx] = '\0'; 1782 1783 free(SLPinfo); 1784 free(hintinfo); 1785 1786filt_ret: 1787 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1788} 1789 1790static void 1791init_dag(Obj_Entry *root) 1792{ 1793 const Needed_Entry *needed; 1794 const Objlist_Entry *elm; 1795 DoneList donelist; 1796 1797 if (root->dag_inited) 1798 return; 1799 donelist_init(&donelist); 1800 1801 /* Root object belongs to own DAG. */ 1802 objlist_push_tail(&root->dldags, root); 1803 objlist_push_tail(&root->dagmembers, root); 1804 donelist_check(&donelist, root); 1805 1806 /* 1807 * Add dependencies of root object to DAG in breadth order 1808 * by exploiting the fact that each new object get added 1809 * to the tail of the dagmembers list. 1810 */ 1811 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1812 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1813 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1814 continue; 1815 objlist_push_tail(&needed->obj->dldags, root); 1816 objlist_push_tail(&root->dagmembers, needed->obj); 1817 } 1818 } 1819 root->dag_inited = true; 1820} 1821 1822Obj_Entry * 1823globallist_curr(const Obj_Entry *obj) 1824{ 1825 1826 for (;;) { 1827 if (obj == NULL) 1828 return (NULL); 1829 if (!obj->marker) 1830 return (__DECONST(Obj_Entry *, obj)); 1831 obj = TAILQ_PREV(obj, obj_entry_q, next); 1832 } 1833} 1834 1835Obj_Entry * 1836globallist_next(const Obj_Entry *obj) 1837{ 1838 1839 for (;;) { 1840 obj = TAILQ_NEXT(obj, next); 1841 if (obj == NULL) 1842 return (NULL); 1843 if (!obj->marker) 1844 return (__DECONST(Obj_Entry *, obj)); 1845 } 1846} 1847 1848static void 1849process_z(Obj_Entry *root) 1850{ 1851 const Objlist_Entry *elm; 1852 Obj_Entry *obj; 1853 1854 /* 1855 * Walk over object DAG and process every dependent object 1856 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1857 * to grow their own DAG. 1858 * 1859 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1860 * symlook_global() to work. 1861 * 1862 * For DF_1_NODELETE, the DAG should have its reference upped. 1863 */ 1864 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1865 obj = elm->obj; 1866 if (obj == NULL) 1867 continue; 1868 if (obj->z_nodelete && !obj->ref_nodel) { 1869 dbg("obj %s -z nodelete", obj->path); 1870 init_dag(obj); 1871 ref_dag(obj); 1872 obj->ref_nodel = true; 1873 } 1874 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1875 dbg("obj %s -z global", obj->path); 1876 objlist_push_tail(&list_global, obj); 1877 init_dag(obj); 1878 } 1879 } 1880} 1881/* 1882 * Initialize the dynamic linker. The argument is the address at which 1883 * the dynamic linker has been mapped into memory. The primary task of 1884 * this function is to relocate the dynamic linker. 1885 */ 1886static void 1887init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1888{ 1889 Obj_Entry objtmp; /* Temporary rtld object */ 1890 const Elf_Ehdr *ehdr; 1891 const Elf_Dyn *dyn_rpath; 1892 const Elf_Dyn *dyn_soname; 1893 const Elf_Dyn *dyn_runpath; 1894 1895#ifdef RTLD_INIT_PAGESIZES_EARLY 1896 /* The page size is required by the dynamic memory allocator. */ 1897 init_pagesizes(aux_info); 1898#endif 1899 1900 /* 1901 * Conjure up an Obj_Entry structure for the dynamic linker. 1902 * 1903 * The "path" member can't be initialized yet because string constants 1904 * cannot yet be accessed. Below we will set it correctly. 1905 */ 1906 memset(&objtmp, 0, sizeof(objtmp)); 1907 objtmp.path = NULL; 1908 objtmp.rtld = true; 1909 objtmp.mapbase = mapbase; 1910#ifdef PIC 1911 objtmp.relocbase = mapbase; 1912#endif 1913 if (RTLD_IS_DYNAMIC()) { 1914 objtmp.dynamic = rtld_dynamic(&objtmp); 1915 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1916 assert(objtmp.needed == NULL); 1917#if !defined(__mips__) 1918 /* MIPS has a bogus DT_TEXTREL. */ 1919 assert(!objtmp.textrel); 1920#endif 1921 1922 /* 1923 * Temporarily put the dynamic linker entry into the object list, so 1924 * that symbols can be found. 1925 */ 1926 1927 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1928 } 1929 ehdr = (Elf_Ehdr *)mapbase; 1930 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1931 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1932 1933 /* Initialize the object list. */ 1934 TAILQ_INIT(&obj_list); 1935 1936 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1937 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1938 1939#ifndef RTLD_INIT_PAGESIZES_EARLY 1940 /* The page size is required by the dynamic memory allocator. */ 1941 init_pagesizes(aux_info); 1942#endif 1943 1944 if (aux_info[AT_OSRELDATE] != NULL) 1945 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1946 1947 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1948 1949 /* Replace the path with a dynamically allocated copy. */ 1950 obj_rtld.path = xstrdup(PATH_RTLD); 1951 1952 r_debug.r_brk = r_debug_state; 1953 r_debug.r_state = RT_CONSISTENT; 1954} 1955 1956/* 1957 * Retrieve the array of supported page sizes. The kernel provides the page 1958 * sizes in increasing order. 1959 */ 1960static void 1961init_pagesizes(Elf_Auxinfo **aux_info) 1962{ 1963 static size_t psa[MAXPAGESIZES]; 1964 int mib[2]; 1965 size_t len, size; 1966 1967 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1968 NULL) { 1969 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1970 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1971 } else { 1972 len = 2; 1973 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1974 size = sizeof(psa); 1975 else { 1976 /* As a fallback, retrieve the base page size. */ 1977 size = sizeof(psa[0]); 1978 if (aux_info[AT_PAGESZ] != NULL) { 1979 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1980 goto psa_filled; 1981 } else { 1982 mib[0] = CTL_HW; 1983 mib[1] = HW_PAGESIZE; 1984 len = 2; 1985 } 1986 } 1987 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1988 _rtld_error("sysctl for hw.pagesize(s) failed"); 1989 rtld_die(); 1990 } 1991psa_filled: 1992 pagesizes = psa; 1993 } 1994 npagesizes = size / sizeof(pagesizes[0]); 1995 /* Discard any invalid entries at the end of the array. */ 1996 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1997 npagesizes--; 1998} 1999 2000/* 2001 * Add the init functions from a needed object list (and its recursive 2002 * needed objects) to "list". This is not used directly; it is a helper 2003 * function for initlist_add_objects(). The write lock must be held 2004 * when this function is called. 2005 */ 2006static void 2007initlist_add_neededs(Needed_Entry *needed, Objlist *list) 2008{ 2009 /* Recursively process the successor needed objects. */ 2010 if (needed->next != NULL) 2011 initlist_add_neededs(needed->next, list); 2012 2013 /* Process the current needed object. */ 2014 if (needed->obj != NULL) 2015 initlist_add_objects(needed->obj, needed->obj, list); 2016} 2017 2018/* 2019 * Scan all of the DAGs rooted in the range of objects from "obj" to 2020 * "tail" and add their init functions to "list". This recurses over 2021 * the DAGs and ensure the proper init ordering such that each object's 2022 * needed libraries are initialized before the object itself. At the 2023 * same time, this function adds the objects to the global finalization 2024 * list "list_fini" in the opposite order. The write lock must be 2025 * held when this function is called. 2026 */ 2027static void 2028initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) 2029{ 2030 Obj_Entry *nobj; 2031 2032 if (obj->init_scanned || obj->init_done) 2033 return; 2034 obj->init_scanned = true; 2035 2036 /* Recursively process the successor objects. */ 2037 nobj = globallist_next(obj); 2038 if (nobj != NULL && obj != tail) 2039 initlist_add_objects(nobj, tail, list); 2040 2041 /* Recursively process the needed objects. */ 2042 if (obj->needed != NULL) 2043 initlist_add_neededs(obj->needed, list); 2044 if (obj->needed_filtees != NULL) 2045 initlist_add_neededs(obj->needed_filtees, list); 2046 if (obj->needed_aux_filtees != NULL) 2047 initlist_add_neededs(obj->needed_aux_filtees, list); 2048 2049 /* Add the object to the init list. */ 2050 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 2051 obj->init_array != (Elf_Addr)NULL) 2052 objlist_push_tail(list, obj); 2053 2054 /* Add the object to the global fini list in the reverse order. */ 2055 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2056 && !obj->on_fini_list) { 2057 objlist_push_head(&list_fini, obj); 2058 obj->on_fini_list = true; 2059 } 2060} 2061 2062#ifndef FPTR_TARGET 2063#define FPTR_TARGET(f) ((Elf_Addr) (f)) 2064#endif 2065 2066static void 2067free_needed_filtees(Needed_Entry *n) 2068{ 2069 Needed_Entry *needed, *needed1; 2070 2071 for (needed = n; needed != NULL; needed = needed->next) { 2072 if (needed->obj != NULL) { 2073 dlclose(needed->obj); 2074 needed->obj = NULL; 2075 } 2076 } 2077 for (needed = n; needed != NULL; needed = needed1) { 2078 needed1 = needed->next; 2079 free(needed); 2080 } 2081} 2082 2083static void 2084unload_filtees(Obj_Entry *obj) 2085{ 2086 2087 free_needed_filtees(obj->needed_filtees); 2088 obj->needed_filtees = NULL; 2089 free_needed_filtees(obj->needed_aux_filtees); 2090 obj->needed_aux_filtees = NULL; 2091 obj->filtees_loaded = false; 2092} 2093 2094static void 2095load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2096 RtldLockState *lockstate) 2097{ 2098 2099 for (; needed != NULL; needed = needed->next) { 2100 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2101 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2102 RTLD_LOCAL, lockstate); 2103 } 2104} 2105 2106static void 2107load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2108{ 2109 2110 lock_restart_for_upgrade(lockstate); 2111 if (!obj->filtees_loaded) { 2112 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2113 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2114 obj->filtees_loaded = true; 2115 } 2116} 2117 2118static int 2119process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2120{ 2121 Obj_Entry *obj1; 2122 2123 for (; needed != NULL; needed = needed->next) { 2124 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2125 flags & ~RTLD_LO_NOLOAD); 2126 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2127 return (-1); 2128 } 2129 return (0); 2130} 2131 2132/* 2133 * Given a shared object, traverse its list of needed objects, and load 2134 * each of them. Returns 0 on success. Generates an error message and 2135 * returns -1 on failure. 2136 */ 2137static int 2138load_needed_objects(Obj_Entry *first, int flags) 2139{ 2140 Obj_Entry *obj; 2141 2142 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2143 if (obj->marker) 2144 continue; 2145 if (process_needed(obj, obj->needed, flags) == -1) 2146 return (-1); 2147 } 2148 return (0); 2149} 2150 2151static int 2152load_preload_objects(void) 2153{ 2154 char *p = ld_preload; 2155 Obj_Entry *obj; 2156 static const char delim[] = " \t:;"; 2157 2158 if (p == NULL) 2159 return 0; 2160 2161 p += strspn(p, delim); 2162 while (*p != '\0') { 2163 size_t len = strcspn(p, delim); 2164 char savech; 2165 2166 savech = p[len]; 2167 p[len] = '\0'; 2168 obj = load_object(p, -1, NULL, 0); 2169 if (obj == NULL) 2170 return -1; /* XXX - cleanup */ 2171 obj->z_interpose = true; 2172 p[len] = savech; 2173 p += len; 2174 p += strspn(p, delim); 2175 } 2176 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2177 return 0; 2178} 2179 2180static const char * 2181printable_path(const char *path) 2182{ 2183 2184 return (path == NULL ? "<unknown>" : path); 2185} 2186 2187/* 2188 * Load a shared object into memory, if it is not already loaded. The 2189 * object may be specified by name or by user-supplied file descriptor 2190 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2191 * duplicate is. 2192 * 2193 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2194 * on failure. 2195 */ 2196static Obj_Entry * 2197load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2198{ 2199 Obj_Entry *obj; 2200 int fd; 2201 struct stat sb; 2202 char *path; 2203 2204 if (name != NULL) { 2205 TAILQ_FOREACH(obj, &obj_list, next) { 2206 if (obj->marker) 2207 continue; 2208 if (object_match_name(obj, name)) 2209 return (obj); 2210 } 2211 2212 path = find_library(name, refobj); 2213 if (path == NULL) 2214 return (NULL); 2215 } else 2216 path = NULL; 2217 2218 /* 2219 * If we didn't find a match by pathname, or the name is not 2220 * supplied, open the file and check again by device and inode. 2221 * This avoids false mismatches caused by multiple links or ".." 2222 * in pathnames. 2223 * 2224 * To avoid a race, we open the file and use fstat() rather than 2225 * using stat(). 2226 */ 2227 fd = -1; 2228 if (fd_u == -1) { 2229 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2230 _rtld_error("Cannot open \"%s\"", path); 2231 free(path); 2232 return (NULL); 2233 } 2234 } else { 2235 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2236 if (fd == -1) { 2237 _rtld_error("Cannot dup fd"); 2238 free(path); 2239 return (NULL); 2240 } 2241 } 2242 if (fstat(fd, &sb) == -1) { 2243 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2244 close(fd); 2245 free(path); 2246 return NULL; 2247 } 2248 TAILQ_FOREACH(obj, &obj_list, next) { 2249 if (obj->marker) 2250 continue; 2251 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2252 break; 2253 } 2254 if (obj != NULL && name != NULL) { 2255 object_add_name(obj, name); 2256 free(path); 2257 close(fd); 2258 return obj; 2259 } 2260 if (flags & RTLD_LO_NOLOAD) { 2261 free(path); 2262 close(fd); 2263 return (NULL); 2264 } 2265 2266 /* First use of this object, so we must map it in */ 2267 obj = do_load_object(fd, name, path, &sb, flags); 2268 if (obj == NULL) 2269 free(path); 2270 close(fd); 2271 2272 return obj; 2273} 2274 2275static Obj_Entry * 2276do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2277 int flags) 2278{ 2279 Obj_Entry *obj; 2280 struct statfs fs; 2281 2282 /* 2283 * but first, make sure that environment variables haven't been 2284 * used to circumvent the noexec flag on a filesystem. 2285 */ 2286 if (dangerous_ld_env) { 2287 if (fstatfs(fd, &fs) != 0) { 2288 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2289 return NULL; 2290 } 2291 if (fs.f_flags & MNT_NOEXEC) { 2292 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2293 return NULL; 2294 } 2295 } 2296 dbg("loading \"%s\"", printable_path(path)); 2297 obj = map_object(fd, printable_path(path), sbp); 2298 if (obj == NULL) 2299 return NULL; 2300 2301 /* 2302 * If DT_SONAME is present in the object, digest_dynamic2 already 2303 * added it to the object names. 2304 */ 2305 if (name != NULL) 2306 object_add_name(obj, name); 2307 obj->path = path; 2308 digest_dynamic(obj, 0); 2309 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2310 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2311 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2312 RTLD_LO_DLOPEN) { 2313 dbg("refusing to load non-loadable \"%s\"", obj->path); 2314 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2315 munmap(obj->mapbase, obj->mapsize); 2316 obj_free(obj); 2317 return (NULL); 2318 } 2319 2320 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2321 TAILQ_INSERT_TAIL(&obj_list, obj, next); 2322 obj_count++; 2323 obj_loads++; 2324 linkmap_add(obj); /* for GDB & dlinfo() */ 2325 max_stack_flags |= obj->stack_flags; 2326 2327 dbg(" %p .. %p: %s", obj->mapbase, 2328 obj->mapbase + obj->mapsize - 1, obj->path); 2329 if (obj->textrel) 2330 dbg(" WARNING: %s has impure text", obj->path); 2331 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2332 obj->path); 2333 2334 return obj; 2335} 2336 2337static Obj_Entry * 2338obj_from_addr(const void *addr) 2339{ 2340 Obj_Entry *obj; 2341 2342 TAILQ_FOREACH(obj, &obj_list, next) { 2343 if (obj->marker) 2344 continue; 2345 if (addr < (void *) obj->mapbase) 2346 continue; 2347 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2348 return obj; 2349 } 2350 return NULL; 2351} 2352 2353static void 2354preinit_main(void) 2355{ 2356 Elf_Addr *preinit_addr; 2357 int index; 2358 2359 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2360 if (preinit_addr == NULL) 2361 return; 2362 2363 for (index = 0; index < obj_main->preinit_array_num; index++) { 2364 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2365 dbg("calling preinit function for %s at %p", obj_main->path, 2366 (void *)preinit_addr[index]); 2367 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2368 0, 0, obj_main->path); 2369 call_init_pointer(obj_main, preinit_addr[index]); 2370 } 2371 } 2372} 2373 2374/* 2375 * Call the finalization functions for each of the objects in "list" 2376 * belonging to the DAG of "root" and referenced once. If NULL "root" 2377 * is specified, every finalization function will be called regardless 2378 * of the reference count and the list elements won't be freed. All of 2379 * the objects are expected to have non-NULL fini functions. 2380 */ 2381static void 2382objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2383{ 2384 Objlist_Entry *elm; 2385 char *saved_msg; 2386 Elf_Addr *fini_addr; 2387 int index; 2388 2389 assert(root == NULL || root->refcount == 1); 2390 2391 /* 2392 * Preserve the current error message since a fini function might 2393 * call into the dynamic linker and overwrite it. 2394 */ 2395 saved_msg = errmsg_save(); 2396 do { 2397 STAILQ_FOREACH(elm, list, link) { 2398 if (root != NULL && (elm->obj->refcount != 1 || 2399 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2400 continue; 2401 /* Remove object from fini list to prevent recursive invocation. */ 2402 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2403 /* 2404 * XXX: If a dlopen() call references an object while the 2405 * fini function is in progress, we might end up trying to 2406 * unload the referenced object in dlclose() or the object 2407 * won't be unloaded although its fini function has been 2408 * called. 2409 */ 2410 lock_release(rtld_bind_lock, lockstate); 2411 2412 /* 2413 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2414 * When this happens, DT_FINI_ARRAY is processed first. 2415 */ 2416 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2417 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2418 for (index = elm->obj->fini_array_num - 1; index >= 0; 2419 index--) { 2420 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2421 dbg("calling fini function for %s at %p", 2422 elm->obj->path, (void *)fini_addr[index]); 2423 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2424 (void *)fini_addr[index], 0, 0, elm->obj->path); 2425 call_initfini_pointer(elm->obj, fini_addr[index]); 2426 } 2427 } 2428 } 2429 if (elm->obj->fini != (Elf_Addr)NULL) { 2430 dbg("calling fini function for %s at %p", elm->obj->path, 2431 (void *)elm->obj->fini); 2432 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2433 0, 0, elm->obj->path); 2434 call_initfini_pointer(elm->obj, elm->obj->fini); 2435 } 2436 wlock_acquire(rtld_bind_lock, lockstate); 2437 /* No need to free anything if process is going down. */ 2438 if (root != NULL) 2439 free(elm); 2440 /* 2441 * We must restart the list traversal after every fini call 2442 * because a dlclose() call from the fini function or from 2443 * another thread might have modified the reference counts. 2444 */ 2445 break; 2446 } 2447 } while (elm != NULL); 2448 errmsg_restore(saved_msg); 2449} 2450 2451/* 2452 * Call the initialization functions for each of the objects in 2453 * "list". All of the objects are expected to have non-NULL init 2454 * functions. 2455 */ 2456static void 2457objlist_call_init(Objlist *list, RtldLockState *lockstate) 2458{ 2459 Objlist_Entry *elm; 2460 Obj_Entry *obj; 2461 char *saved_msg; 2462 Elf_Addr *init_addr; 2463 int index; 2464 2465 /* 2466 * Clean init_scanned flag so that objects can be rechecked and 2467 * possibly initialized earlier if any of vectors called below 2468 * cause the change by using dlopen. 2469 */ 2470 TAILQ_FOREACH(obj, &obj_list, next) { 2471 if (obj->marker) 2472 continue; 2473 obj->init_scanned = false; 2474 } 2475 2476 /* 2477 * Preserve the current error message since an init function might 2478 * call into the dynamic linker and overwrite it. 2479 */ 2480 saved_msg = errmsg_save(); 2481 STAILQ_FOREACH(elm, list, link) { 2482 if (elm->obj->init_done) /* Initialized early. */ 2483 continue; 2484 /* 2485 * Race: other thread might try to use this object before current 2486 * one completes the initialization. Not much can be done here 2487 * without better locking. 2488 */ 2489 elm->obj->init_done = true; 2490 lock_release(rtld_bind_lock, lockstate); 2491 2492 /* 2493 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2494 * When this happens, DT_INIT is processed first. 2495 */ 2496 if (elm->obj->init != (Elf_Addr)NULL) { 2497 dbg("calling init function for %s at %p", elm->obj->path, 2498 (void *)elm->obj->init); 2499 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2500 0, 0, elm->obj->path); 2501 call_initfini_pointer(elm->obj, elm->obj->init); 2502 } 2503 init_addr = (Elf_Addr *)elm->obj->init_array; 2504 if (init_addr != NULL) { 2505 for (index = 0; index < elm->obj->init_array_num; index++) { 2506 if (init_addr[index] != 0 && init_addr[index] != 1) { 2507 dbg("calling init function for %s at %p", elm->obj->path, 2508 (void *)init_addr[index]); 2509 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2510 (void *)init_addr[index], 0, 0, elm->obj->path); 2511 call_init_pointer(elm->obj, init_addr[index]); 2512 } 2513 } 2514 } 2515 wlock_acquire(rtld_bind_lock, lockstate); 2516 } 2517 errmsg_restore(saved_msg); 2518} 2519 2520static void 2521objlist_clear(Objlist *list) 2522{ 2523 Objlist_Entry *elm; 2524 2525 while (!STAILQ_EMPTY(list)) { 2526 elm = STAILQ_FIRST(list); 2527 STAILQ_REMOVE_HEAD(list, link); 2528 free(elm); 2529 } 2530} 2531 2532static Objlist_Entry * 2533objlist_find(Objlist *list, const Obj_Entry *obj) 2534{ 2535 Objlist_Entry *elm; 2536 2537 STAILQ_FOREACH(elm, list, link) 2538 if (elm->obj == obj) 2539 return elm; 2540 return NULL; 2541} 2542 2543static void 2544objlist_init(Objlist *list) 2545{ 2546 STAILQ_INIT(list); 2547} 2548 2549static void 2550objlist_push_head(Objlist *list, Obj_Entry *obj) 2551{ 2552 Objlist_Entry *elm; 2553 2554 elm = NEW(Objlist_Entry); 2555 elm->obj = obj; 2556 STAILQ_INSERT_HEAD(list, elm, link); 2557} 2558 2559static void 2560objlist_push_tail(Objlist *list, Obj_Entry *obj) 2561{ 2562 Objlist_Entry *elm; 2563 2564 elm = NEW(Objlist_Entry); 2565 elm->obj = obj; 2566 STAILQ_INSERT_TAIL(list, elm, link); 2567} 2568 2569static void 2570objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2571{ 2572 Objlist_Entry *elm, *listelm; 2573 2574 STAILQ_FOREACH(listelm, list, link) { 2575 if (listelm->obj == listobj) 2576 break; 2577 } 2578 elm = NEW(Objlist_Entry); 2579 elm->obj = obj; 2580 if (listelm != NULL) 2581 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2582 else 2583 STAILQ_INSERT_TAIL(list, elm, link); 2584} 2585 2586static void 2587objlist_remove(Objlist *list, Obj_Entry *obj) 2588{ 2589 Objlist_Entry *elm; 2590 2591 if ((elm = objlist_find(list, obj)) != NULL) { 2592 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2593 free(elm); 2594 } 2595} 2596 2597/* 2598 * Relocate dag rooted in the specified object. 2599 * Returns 0 on success, or -1 on failure. 2600 */ 2601 2602static int 2603relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2604 int flags, RtldLockState *lockstate) 2605{ 2606 Objlist_Entry *elm; 2607 int error; 2608 2609 error = 0; 2610 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2611 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2612 lockstate); 2613 if (error == -1) 2614 break; 2615 } 2616 return (error); 2617} 2618 2619/* 2620 * Prepare for, or clean after, relocating an object marked with 2621 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2622 * segments are remapped read-write. After relocations are done, the 2623 * segment's permissions are returned back to the modes specified in 2624 * the phdrs. If any relocation happened, or always for wired 2625 * program, COW is triggered. 2626 */ 2627static int 2628reloc_textrel_prot(Obj_Entry *obj, bool before) 2629{ 2630 const Elf_Phdr *ph; 2631 void *base; 2632 size_t l, sz; 2633 int prot; 2634 2635 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2636 l--, ph++) { 2637 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2638 continue; 2639 base = obj->relocbase + trunc_page(ph->p_vaddr); 2640 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2641 trunc_page(ph->p_vaddr); 2642 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2643 if (mprotect(base, sz, prot) == -1) { 2644 _rtld_error("%s: Cannot write-%sable text segment: %s", 2645 obj->path, before ? "en" : "dis", 2646 rtld_strerror(errno)); 2647 return (-1); 2648 } 2649 } 2650 return (0); 2651} 2652 2653/* 2654 * Relocate single object. 2655 * Returns 0 on success, or -1 on failure. 2656 */ 2657static int 2658relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2659 int flags, RtldLockState *lockstate) 2660{ 2661 2662 if (obj->relocated) 2663 return (0); 2664 obj->relocated = true; 2665 if (obj != rtldobj) 2666 dbg("relocating \"%s\"", obj->path); 2667 2668 if (obj->symtab == NULL || obj->strtab == NULL || 2669 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2670 _rtld_error("%s: Shared object has no run-time symbol table", 2671 obj->path); 2672 return (-1); 2673 } 2674 2675 /* There are relocations to the write-protected text segment. */ 2676 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2677 return (-1); 2678 2679 /* Process the non-PLT non-IFUNC relocations. */ 2680 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2681 return (-1); 2682 2683 /* Re-protected the text segment. */ 2684 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2685 return (-1); 2686 2687 /* Set the special PLT or GOT entries. */ 2688 init_pltgot(obj); 2689 2690 /* Process the PLT relocations. */ 2691 if (reloc_plt(obj) == -1) 2692 return (-1); 2693 /* Relocate the jump slots if we are doing immediate binding. */ 2694 if (obj->bind_now || bind_now) 2695 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2696 return (-1); 2697 2698 /* 2699 * Process the non-PLT IFUNC relocations. The relocations are 2700 * processed in two phases, because IFUNC resolvers may 2701 * reference other symbols, which must be readily processed 2702 * before resolvers are called. 2703 */ 2704 if (obj->non_plt_gnu_ifunc && 2705 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2706 return (-1); 2707 2708 if (!obj->mainprog && obj_enforce_relro(obj) == -1) 2709 return (-1); 2710 2711 /* 2712 * Set up the magic number and version in the Obj_Entry. These 2713 * were checked in the crt1.o from the original ElfKit, so we 2714 * set them for backward compatibility. 2715 */ 2716 obj->magic = RTLD_MAGIC; 2717 obj->version = RTLD_VERSION; 2718 2719 return (0); 2720} 2721 2722/* 2723 * Relocate newly-loaded shared objects. The argument is a pointer to 2724 * the Obj_Entry for the first such object. All objects from the first 2725 * to the end of the list of objects are relocated. Returns 0 on success, 2726 * or -1 on failure. 2727 */ 2728static int 2729relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2730 int flags, RtldLockState *lockstate) 2731{ 2732 Obj_Entry *obj; 2733 int error; 2734 2735 for (error = 0, obj = first; obj != NULL; 2736 obj = TAILQ_NEXT(obj, next)) { 2737 if (obj->marker) 2738 continue; 2739 error = relocate_object(obj, bind_now, rtldobj, flags, 2740 lockstate); 2741 if (error == -1) 2742 break; 2743 } 2744 return (error); 2745} 2746 2747/* 2748 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2749 * referencing STT_GNU_IFUNC symbols is postponed till the other 2750 * relocations are done. The indirect functions specified as 2751 * ifunc are allowed to call other symbols, so we need to have 2752 * objects relocated before asking for resolution from indirects. 2753 * 2754 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2755 * instead of the usual lazy handling of PLT slots. It is 2756 * consistent with how GNU does it. 2757 */ 2758static int 2759resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2760 RtldLockState *lockstate) 2761{ 2762 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2763 return (-1); 2764 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2765 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2766 return (-1); 2767 return (0); 2768} 2769 2770static int 2771resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2772 RtldLockState *lockstate) 2773{ 2774 Obj_Entry *obj; 2775 2776 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 2777 if (obj->marker) 2778 continue; 2779 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2780 return (-1); 2781 } 2782 return (0); 2783} 2784 2785static int 2786initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2787 RtldLockState *lockstate) 2788{ 2789 Objlist_Entry *elm; 2790 2791 STAILQ_FOREACH(elm, list, link) { 2792 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2793 lockstate) == -1) 2794 return (-1); 2795 } 2796 return (0); 2797} 2798 2799/* 2800 * Cleanup procedure. It will be called (by the atexit mechanism) just 2801 * before the process exits. 2802 */ 2803static void 2804rtld_exit(void) 2805{ 2806 RtldLockState lockstate; 2807 2808 wlock_acquire(rtld_bind_lock, &lockstate); 2809 dbg("rtld_exit()"); 2810 objlist_call_fini(&list_fini, NULL, &lockstate); 2811 /* No need to remove the items from the list, since we are exiting. */ 2812 if (!libmap_disable) 2813 lm_fini(); 2814 lock_release(rtld_bind_lock, &lockstate); 2815} 2816 2817/* 2818 * Iterate over a search path, translate each element, and invoke the 2819 * callback on the result. 2820 */ 2821static void * 2822path_enumerate(const char *path, path_enum_proc callback, void *arg) 2823{ 2824 const char *trans; 2825 if (path == NULL) 2826 return (NULL); 2827 2828 path += strspn(path, ":;"); 2829 while (*path != '\0') { 2830 size_t len; 2831 char *res; 2832 2833 len = strcspn(path, ":;"); 2834 trans = lm_findn(NULL, path, len); 2835 if (trans) 2836 res = callback(trans, strlen(trans), arg); 2837 else 2838 res = callback(path, len, arg); 2839 2840 if (res != NULL) 2841 return (res); 2842 2843 path += len; 2844 path += strspn(path, ":;"); 2845 } 2846 2847 return (NULL); 2848} 2849 2850struct try_library_args { 2851 const char *name; 2852 size_t namelen; 2853 char *buffer; 2854 size_t buflen; 2855}; 2856 2857static void * 2858try_library_path(const char *dir, size_t dirlen, void *param) 2859{ 2860 struct try_library_args *arg; 2861 2862 arg = param; 2863 if (*dir == '/' || trust) { 2864 char *pathname; 2865 2866 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2867 return (NULL); 2868 2869 pathname = arg->buffer; 2870 strncpy(pathname, dir, dirlen); 2871 pathname[dirlen] = '/'; 2872 strcpy(pathname + dirlen + 1, arg->name); 2873 2874 dbg(" Trying \"%s\"", pathname); 2875 if (access(pathname, F_OK) == 0) { /* We found it */ 2876 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2877 strcpy(pathname, arg->buffer); 2878 return (pathname); 2879 } 2880 } 2881 return (NULL); 2882} 2883 2884static char * 2885search_library_path(const char *name, const char *path) 2886{ 2887 char *p; 2888 struct try_library_args arg; 2889 2890 if (path == NULL) 2891 return NULL; 2892 2893 arg.name = name; 2894 arg.namelen = strlen(name); 2895 arg.buffer = xmalloc(PATH_MAX); 2896 arg.buflen = PATH_MAX; 2897 2898 p = path_enumerate(path, try_library_path, &arg); 2899 2900 free(arg.buffer); 2901 2902 return (p); 2903} 2904 2905int 2906dlclose(void *handle) 2907{ 2908 Obj_Entry *root; 2909 RtldLockState lockstate; 2910 2911 wlock_acquire(rtld_bind_lock, &lockstate); 2912 root = dlcheck(handle); 2913 if (root == NULL) { 2914 lock_release(rtld_bind_lock, &lockstate); 2915 return -1; 2916 } 2917 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2918 root->path); 2919 2920 /* Unreference the object and its dependencies. */ 2921 root->dl_refcount--; 2922 2923 if (root->refcount == 1) { 2924 /* 2925 * The object will be no longer referenced, so we must unload it. 2926 * First, call the fini functions. 2927 */ 2928 objlist_call_fini(&list_fini, root, &lockstate); 2929 2930 unref_dag(root); 2931 2932 /* Finish cleaning up the newly-unreferenced objects. */ 2933 GDB_STATE(RT_DELETE,&root->linkmap); 2934 unload_object(root); 2935 GDB_STATE(RT_CONSISTENT,NULL); 2936 } else 2937 unref_dag(root); 2938 2939 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2940 lock_release(rtld_bind_lock, &lockstate); 2941 return 0; 2942} 2943 2944char * 2945dlerror(void) 2946{ 2947 char *msg = error_message; 2948 error_message = NULL; 2949 return msg; 2950} 2951 2952/* 2953 * This function is deprecated and has no effect. 2954 */ 2955void 2956dllockinit(void *context, 2957 void *(*lock_create)(void *context), 2958 void (*rlock_acquire)(void *lock), 2959 void (*wlock_acquire)(void *lock), 2960 void (*lock_release)(void *lock), 2961 void (*lock_destroy)(void *lock), 2962 void (*context_destroy)(void *context)) 2963{ 2964 static void *cur_context; 2965 static void (*cur_context_destroy)(void *); 2966 2967 /* Just destroy the context from the previous call, if necessary. */ 2968 if (cur_context_destroy != NULL) 2969 cur_context_destroy(cur_context); 2970 cur_context = context; 2971 cur_context_destroy = context_destroy; 2972} 2973 2974void * 2975dlopen(const char *name, int mode) 2976{ 2977 2978 return (rtld_dlopen(name, -1, mode)); 2979} 2980 2981void * 2982fdlopen(int fd, int mode) 2983{ 2984 2985 return (rtld_dlopen(NULL, fd, mode)); 2986} 2987 2988static void * 2989rtld_dlopen(const char *name, int fd, int mode) 2990{ 2991 RtldLockState lockstate; 2992 int lo_flags; 2993 2994 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2995 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2996 if (ld_tracing != NULL) { 2997 rlock_acquire(rtld_bind_lock, &lockstate); 2998 if (sigsetjmp(lockstate.env, 0) != 0) 2999 lock_upgrade(rtld_bind_lock, &lockstate); 3000 environ = (char **)*get_program_var_addr("environ", &lockstate); 3001 lock_release(rtld_bind_lock, &lockstate); 3002 } 3003 lo_flags = RTLD_LO_DLOPEN; 3004 if (mode & RTLD_NODELETE) 3005 lo_flags |= RTLD_LO_NODELETE; 3006 if (mode & RTLD_NOLOAD) 3007 lo_flags |= RTLD_LO_NOLOAD; 3008 if (ld_tracing != NULL) 3009 lo_flags |= RTLD_LO_TRACE; 3010 3011 return (dlopen_object(name, fd, obj_main, lo_flags, 3012 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3013} 3014 3015static void 3016dlopen_cleanup(Obj_Entry *obj) 3017{ 3018 3019 obj->dl_refcount--; 3020 unref_dag(obj); 3021 if (obj->refcount == 0) 3022 unload_object(obj); 3023} 3024 3025static Obj_Entry * 3026dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3027 int mode, RtldLockState *lockstate) 3028{ 3029 Obj_Entry *old_obj_tail; 3030 Obj_Entry *obj; 3031 Objlist initlist; 3032 RtldLockState mlockstate; 3033 int result; 3034 3035 objlist_init(&initlist); 3036 3037 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3038 wlock_acquire(rtld_bind_lock, &mlockstate); 3039 lockstate = &mlockstate; 3040 } 3041 GDB_STATE(RT_ADD,NULL); 3042 3043 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); 3044 obj = NULL; 3045 if (name == NULL && fd == -1) { 3046 obj = obj_main; 3047 obj->refcount++; 3048 } else { 3049 obj = load_object(name, fd, refobj, lo_flags); 3050 } 3051 3052 if (obj) { 3053 obj->dl_refcount++; 3054 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3055 objlist_push_tail(&list_global, obj); 3056 if (globallist_next(old_obj_tail) != NULL) { 3057 /* We loaded something new. */ 3058 assert(globallist_next(old_obj_tail) == obj); 3059 result = load_needed_objects(obj, 3060 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3061 init_dag(obj); 3062 ref_dag(obj); 3063 if (result != -1) 3064 result = rtld_verify_versions(&obj->dagmembers); 3065 if (result != -1 && ld_tracing) 3066 goto trace; 3067 if (result == -1 || relocate_object_dag(obj, 3068 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3069 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3070 lockstate) == -1) { 3071 dlopen_cleanup(obj); 3072 obj = NULL; 3073 } else if (lo_flags & RTLD_LO_EARLY) { 3074 /* 3075 * Do not call the init functions for early loaded 3076 * filtees. The image is still not initialized enough 3077 * for them to work. 3078 * 3079 * Our object is found by the global object list and 3080 * will be ordered among all init calls done right 3081 * before transferring control to main. 3082 */ 3083 } else { 3084 /* Make list of init functions to call. */ 3085 initlist_add_objects(obj, obj, &initlist); 3086 } 3087 /* 3088 * Process all no_delete or global objects here, given 3089 * them own DAGs to prevent their dependencies from being 3090 * unloaded. This has to be done after we have loaded all 3091 * of the dependencies, so that we do not miss any. 3092 */ 3093 if (obj != NULL) 3094 process_z(obj); 3095 } else { 3096 /* 3097 * Bump the reference counts for objects on this DAG. If 3098 * this is the first dlopen() call for the object that was 3099 * already loaded as a dependency, initialize the dag 3100 * starting at it. 3101 */ 3102 init_dag(obj); 3103 ref_dag(obj); 3104 3105 if ((lo_flags & RTLD_LO_TRACE) != 0) 3106 goto trace; 3107 } 3108 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3109 obj->z_nodelete) && !obj->ref_nodel) { 3110 dbg("obj %s nodelete", obj->path); 3111 ref_dag(obj); 3112 obj->z_nodelete = obj->ref_nodel = true; 3113 } 3114 } 3115 3116 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3117 name); 3118 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3119 3120 if (!(lo_flags & RTLD_LO_EARLY)) { 3121 map_stacks_exec(lockstate); 3122 } 3123 3124 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3125 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3126 lockstate) == -1) { 3127 objlist_clear(&initlist); 3128 dlopen_cleanup(obj); 3129 if (lockstate == &mlockstate) 3130 lock_release(rtld_bind_lock, lockstate); 3131 return (NULL); 3132 } 3133 3134 if (!(lo_flags & RTLD_LO_EARLY)) { 3135 /* Call the init functions. */ 3136 objlist_call_init(&initlist, lockstate); 3137 } 3138 objlist_clear(&initlist); 3139 if (lockstate == &mlockstate) 3140 lock_release(rtld_bind_lock, lockstate); 3141 return obj; 3142trace: 3143 trace_loaded_objects(obj); 3144 if (lockstate == &mlockstate) 3145 lock_release(rtld_bind_lock, lockstate); 3146 exit(0); 3147} 3148 3149static void * 3150do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3151 int flags) 3152{ 3153 DoneList donelist; 3154 const Obj_Entry *obj, *defobj; 3155 const Elf_Sym *def; 3156 SymLook req; 3157 RtldLockState lockstate; 3158#ifndef __ia64__ 3159 tls_index ti; 3160#endif 3161 void *sym; 3162 int res; 3163 3164 def = NULL; 3165 defobj = NULL; 3166 symlook_init(&req, name); 3167 req.ventry = ve; 3168 req.flags = flags | SYMLOOK_IN_PLT; 3169 req.lockstate = &lockstate; 3170 3171 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3172 rlock_acquire(rtld_bind_lock, &lockstate); 3173 if (sigsetjmp(lockstate.env, 0) != 0) 3174 lock_upgrade(rtld_bind_lock, &lockstate); 3175 if (handle == NULL || handle == RTLD_NEXT || 3176 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3177 3178 if ((obj = obj_from_addr(retaddr)) == NULL) { 3179 _rtld_error("Cannot determine caller's shared object"); 3180 lock_release(rtld_bind_lock, &lockstate); 3181 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3182 return NULL; 3183 } 3184 if (handle == NULL) { /* Just the caller's shared object. */ 3185 res = symlook_obj(&req, obj); 3186 if (res == 0) { 3187 def = req.sym_out; 3188 defobj = req.defobj_out; 3189 } 3190 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3191 handle == RTLD_SELF) { /* ... caller included */ 3192 if (handle == RTLD_NEXT) 3193 obj = globallist_next(obj); 3194 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 3195 if (obj->marker) 3196 continue; 3197 res = symlook_obj(&req, obj); 3198 if (res == 0) { 3199 if (def == NULL || 3200 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3201 def = req.sym_out; 3202 defobj = req.defobj_out; 3203 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3204 break; 3205 } 3206 } 3207 } 3208 /* 3209 * Search the dynamic linker itself, and possibly resolve the 3210 * symbol from there. This is how the application links to 3211 * dynamic linker services such as dlopen. 3212 */ 3213 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3214 res = symlook_obj(&req, &obj_rtld); 3215 if (res == 0) { 3216 def = req.sym_out; 3217 defobj = req.defobj_out; 3218 } 3219 } 3220 } else { 3221 assert(handle == RTLD_DEFAULT); 3222 res = symlook_default(&req, obj); 3223 if (res == 0) { 3224 defobj = req.defobj_out; 3225 def = req.sym_out; 3226 } 3227 } 3228 } else { 3229 if ((obj = dlcheck(handle)) == NULL) { 3230 lock_release(rtld_bind_lock, &lockstate); 3231 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3232 return NULL; 3233 } 3234 3235 donelist_init(&donelist); 3236 if (obj->mainprog) { 3237 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3238 res = symlook_global(&req, &donelist); 3239 if (res == 0) { 3240 def = req.sym_out; 3241 defobj = req.defobj_out; 3242 } 3243 /* 3244 * Search the dynamic linker itself, and possibly resolve the 3245 * symbol from there. This is how the application links to 3246 * dynamic linker services such as dlopen. 3247 */ 3248 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3249 res = symlook_obj(&req, &obj_rtld); 3250 if (res == 0) { 3251 def = req.sym_out; 3252 defobj = req.defobj_out; 3253 } 3254 } 3255 } 3256 else { 3257 /* Search the whole DAG rooted at the given object. */ 3258 res = symlook_list(&req, &obj->dagmembers, &donelist); 3259 if (res == 0) { 3260 def = req.sym_out; 3261 defobj = req.defobj_out; 3262 } 3263 } 3264 } 3265 3266 if (def != NULL) { 3267 lock_release(rtld_bind_lock, &lockstate); 3268 3269 /* 3270 * The value required by the caller is derived from the value 3271 * of the symbol. For the ia64 architecture, we need to 3272 * construct a function descriptor which the caller can use to 3273 * call the function with the right 'gp' value. For other 3274 * architectures and for non-functions, the value is simply 3275 * the relocated value of the symbol. 3276 */ 3277 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3278 sym = make_function_pointer(def, defobj); 3279 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3280 sym = rtld_resolve_ifunc(defobj, def); 3281 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3282#ifdef __ia64__ 3283 return (__tls_get_addr(defobj->tlsindex, def->st_value)); 3284#else 3285 ti.ti_module = defobj->tlsindex; 3286 ti.ti_offset = def->st_value; 3287 sym = __tls_get_addr(&ti); 3288#endif 3289 } else 3290 sym = defobj->relocbase + def->st_value; 3291 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3292 return (sym); 3293 } 3294 3295 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", 3296 ve != NULL ? ve->name : ""); 3297 lock_release(rtld_bind_lock, &lockstate); 3298 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3299 return NULL; 3300} 3301 3302void * 3303dlsym(void *handle, const char *name) 3304{ 3305 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3306 SYMLOOK_DLSYM); 3307} 3308 3309dlfunc_t 3310dlfunc(void *handle, const char *name) 3311{ 3312 union { 3313 void *d; 3314 dlfunc_t f; 3315 } rv; 3316 3317 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3318 SYMLOOK_DLSYM); 3319 return (rv.f); 3320} 3321 3322void * 3323dlvsym(void *handle, const char *name, const char *version) 3324{ 3325 Ver_Entry ventry; 3326 3327 ventry.name = version; 3328 ventry.file = NULL; 3329 ventry.hash = elf_hash(version); 3330 ventry.flags= 0; 3331 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3332 SYMLOOK_DLSYM); 3333} 3334 3335int 3336_rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3337{ 3338 const Obj_Entry *obj; 3339 RtldLockState lockstate; 3340 3341 rlock_acquire(rtld_bind_lock, &lockstate); 3342 obj = obj_from_addr(addr); 3343 if (obj == NULL) { 3344 _rtld_error("No shared object contains address"); 3345 lock_release(rtld_bind_lock, &lockstate); 3346 return (0); 3347 } 3348 rtld_fill_dl_phdr_info(obj, phdr_info); 3349 lock_release(rtld_bind_lock, &lockstate); 3350 return (1); 3351} 3352 3353int 3354dladdr(const void *addr, Dl_info *info) 3355{ 3356 const Obj_Entry *obj; 3357 const Elf_Sym *def; 3358 void *symbol_addr; 3359 unsigned long symoffset; 3360 RtldLockState lockstate; 3361 3362 rlock_acquire(rtld_bind_lock, &lockstate); 3363 obj = obj_from_addr(addr); 3364 if (obj == NULL) { 3365 _rtld_error("No shared object contains address"); 3366 lock_release(rtld_bind_lock, &lockstate); 3367 return 0; 3368 } 3369 info->dli_fname = obj->path; 3370 info->dli_fbase = obj->mapbase; 3371 info->dli_saddr = (void *)0; 3372 info->dli_sname = NULL; 3373 3374 /* 3375 * Walk the symbol list looking for the symbol whose address is 3376 * closest to the address sent in. 3377 */ 3378 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3379 def = obj->symtab + symoffset; 3380 3381 /* 3382 * For skip the symbol if st_shndx is either SHN_UNDEF or 3383 * SHN_COMMON. 3384 */ 3385 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3386 continue; 3387 3388 /* 3389 * If the symbol is greater than the specified address, or if it 3390 * is further away from addr than the current nearest symbol, 3391 * then reject it. 3392 */ 3393 symbol_addr = obj->relocbase + def->st_value; 3394 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3395 continue; 3396 3397 /* Update our idea of the nearest symbol. */ 3398 info->dli_sname = obj->strtab + def->st_name; 3399 info->dli_saddr = symbol_addr; 3400 3401 /* Exact match? */ 3402 if (info->dli_saddr == addr) 3403 break; 3404 } 3405 lock_release(rtld_bind_lock, &lockstate); 3406 return 1; 3407} 3408 3409int 3410dlinfo(void *handle, int request, void *p) 3411{ 3412 const Obj_Entry *obj; 3413 RtldLockState lockstate; 3414 int error; 3415 3416 rlock_acquire(rtld_bind_lock, &lockstate); 3417 3418 if (handle == NULL || handle == RTLD_SELF) { 3419 void *retaddr; 3420 3421 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3422 if ((obj = obj_from_addr(retaddr)) == NULL) 3423 _rtld_error("Cannot determine caller's shared object"); 3424 } else 3425 obj = dlcheck(handle); 3426 3427 if (obj == NULL) { 3428 lock_release(rtld_bind_lock, &lockstate); 3429 return (-1); 3430 } 3431 3432 error = 0; 3433 switch (request) { 3434 case RTLD_DI_LINKMAP: 3435 *((struct link_map const **)p) = &obj->linkmap; 3436 break; 3437 case RTLD_DI_ORIGIN: 3438 error = rtld_dirname(obj->path, p); 3439 break; 3440 3441 case RTLD_DI_SERINFOSIZE: 3442 case RTLD_DI_SERINFO: 3443 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3444 break; 3445 3446 default: 3447 _rtld_error("Invalid request %d passed to dlinfo()", request); 3448 error = -1; 3449 } 3450 3451 lock_release(rtld_bind_lock, &lockstate); 3452 3453 return (error); 3454} 3455 3456static void 3457rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3458{ 3459 3460 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3461 phdr_info->dlpi_name = obj->path; 3462 phdr_info->dlpi_phdr = obj->phdr; 3463 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3464 phdr_info->dlpi_tls_modid = obj->tlsindex; 3465 phdr_info->dlpi_tls_data = obj->tlsinit; 3466 phdr_info->dlpi_adds = obj_loads; 3467 phdr_info->dlpi_subs = obj_loads - obj_count; 3468} 3469 3470int 3471dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3472{ 3473 struct dl_phdr_info phdr_info; 3474 Obj_Entry *obj, marker; 3475 RtldLockState bind_lockstate, phdr_lockstate; 3476 int error; 3477 3478 bzero(&marker, sizeof(marker)); 3479 marker.marker = true; 3480 error = 0; 3481 3482 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3483 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3484 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { 3485 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); 3486 rtld_fill_dl_phdr_info(obj, &phdr_info); 3487 lock_release(rtld_bind_lock, &bind_lockstate); 3488 3489 error = callback(&phdr_info, sizeof phdr_info, param); 3490 3491 wlock_acquire(rtld_bind_lock, &bind_lockstate); 3492 obj = globallist_next(&marker); 3493 TAILQ_REMOVE(&obj_list, &marker, next); 3494 if (error != 0) { 3495 lock_release(rtld_bind_lock, &bind_lockstate); 3496 lock_release(rtld_phdr_lock, &phdr_lockstate); 3497 return (error); 3498 } 3499 } 3500 3501 if (error == 0) { 3502 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3503 lock_release(rtld_bind_lock, &bind_lockstate); 3504 error = callback(&phdr_info, sizeof(phdr_info), param); 3505 } 3506 lock_release(rtld_phdr_lock, &phdr_lockstate); 3507 return (error); 3508} 3509 3510static void * 3511fill_search_info(const char *dir, size_t dirlen, void *param) 3512{ 3513 struct fill_search_info_args *arg; 3514 3515 arg = param; 3516 3517 if (arg->request == RTLD_DI_SERINFOSIZE) { 3518 arg->serinfo->dls_cnt ++; 3519 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3520 } else { 3521 struct dl_serpath *s_entry; 3522 3523 s_entry = arg->serpath; 3524 s_entry->dls_name = arg->strspace; 3525 s_entry->dls_flags = arg->flags; 3526 3527 strncpy(arg->strspace, dir, dirlen); 3528 arg->strspace[dirlen] = '\0'; 3529 3530 arg->strspace += dirlen + 1; 3531 arg->serpath++; 3532 } 3533 3534 return (NULL); 3535} 3536 3537static int 3538do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3539{ 3540 struct dl_serinfo _info; 3541 struct fill_search_info_args args; 3542 3543 args.request = RTLD_DI_SERINFOSIZE; 3544 args.serinfo = &_info; 3545 3546 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3547 _info.dls_cnt = 0; 3548 3549 path_enumerate(obj->rpath, fill_search_info, &args); 3550 path_enumerate(ld_library_path, fill_search_info, &args); 3551 path_enumerate(obj->runpath, fill_search_info, &args); 3552 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3553 if (!obj->z_nodeflib) 3554 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3555 3556 3557 if (request == RTLD_DI_SERINFOSIZE) { 3558 info->dls_size = _info.dls_size; 3559 info->dls_cnt = _info.dls_cnt; 3560 return (0); 3561 } 3562 3563 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3564 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3565 return (-1); 3566 } 3567 3568 args.request = RTLD_DI_SERINFO; 3569 args.serinfo = info; 3570 args.serpath = &info->dls_serpath[0]; 3571 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3572 3573 args.flags = LA_SER_RUNPATH; 3574 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3575 return (-1); 3576 3577 args.flags = LA_SER_LIBPATH; 3578 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3579 return (-1); 3580 3581 args.flags = LA_SER_RUNPATH; 3582 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3583 return (-1); 3584 3585 args.flags = LA_SER_CONFIG; 3586 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3587 != NULL) 3588 return (-1); 3589 3590 args.flags = LA_SER_DEFAULT; 3591 if (!obj->z_nodeflib && 3592 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3593 return (-1); 3594 return (0); 3595} 3596 3597static int 3598rtld_dirname(const char *path, char *bname) 3599{ 3600 const char *endp; 3601 3602 /* Empty or NULL string gets treated as "." */ 3603 if (path == NULL || *path == '\0') { 3604 bname[0] = '.'; 3605 bname[1] = '\0'; 3606 return (0); 3607 } 3608 3609 /* Strip trailing slashes */ 3610 endp = path + strlen(path) - 1; 3611 while (endp > path && *endp == '/') 3612 endp--; 3613 3614 /* Find the start of the dir */ 3615 while (endp > path && *endp != '/') 3616 endp--; 3617 3618 /* Either the dir is "/" or there are no slashes */ 3619 if (endp == path) { 3620 bname[0] = *endp == '/' ? '/' : '.'; 3621 bname[1] = '\0'; 3622 return (0); 3623 } else { 3624 do { 3625 endp--; 3626 } while (endp > path && *endp == '/'); 3627 } 3628 3629 if (endp - path + 2 > PATH_MAX) 3630 { 3631 _rtld_error("Filename is too long: %s", path); 3632 return(-1); 3633 } 3634 3635 strncpy(bname, path, endp - path + 1); 3636 bname[endp - path + 1] = '\0'; 3637 return (0); 3638} 3639 3640static int 3641rtld_dirname_abs(const char *path, char *base) 3642{ 3643 char *last; 3644 3645 if (realpath(path, base) == NULL) 3646 return (-1); 3647 dbg("%s -> %s", path, base); 3648 last = strrchr(base, '/'); 3649 if (last == NULL) 3650 return (-1); 3651 if (last != base) 3652 *last = '\0'; 3653 return (0); 3654} 3655 3656static void 3657linkmap_add(Obj_Entry *obj) 3658{ 3659 struct link_map *l = &obj->linkmap; 3660 struct link_map *prev; 3661 3662 obj->linkmap.l_name = obj->path; 3663 obj->linkmap.l_addr = obj->mapbase; 3664 obj->linkmap.l_ld = obj->dynamic; 3665#ifdef __mips__ 3666 /* GDB needs load offset on MIPS to use the symbols */ 3667 obj->linkmap.l_offs = obj->relocbase; 3668#endif 3669 3670 if (r_debug.r_map == NULL) { 3671 r_debug.r_map = l; 3672 return; 3673 } 3674 3675 /* 3676 * Scan to the end of the list, but not past the entry for the 3677 * dynamic linker, which we want to keep at the very end. 3678 */ 3679 for (prev = r_debug.r_map; 3680 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3681 prev = prev->l_next) 3682 ; 3683 3684 /* Link in the new entry. */ 3685 l->l_prev = prev; 3686 l->l_next = prev->l_next; 3687 if (l->l_next != NULL) 3688 l->l_next->l_prev = l; 3689 prev->l_next = l; 3690} 3691 3692static void 3693linkmap_delete(Obj_Entry *obj) 3694{ 3695 struct link_map *l = &obj->linkmap; 3696 3697 if (l->l_prev == NULL) { 3698 if ((r_debug.r_map = l->l_next) != NULL) 3699 l->l_next->l_prev = NULL; 3700 return; 3701 } 3702 3703 if ((l->l_prev->l_next = l->l_next) != NULL) 3704 l->l_next->l_prev = l->l_prev; 3705} 3706 3707/* 3708 * Function for the debugger to set a breakpoint on to gain control. 3709 * 3710 * The two parameters allow the debugger to easily find and determine 3711 * what the runtime loader is doing and to whom it is doing it. 3712 * 3713 * When the loadhook trap is hit (r_debug_state, set at program 3714 * initialization), the arguments can be found on the stack: 3715 * 3716 * +8 struct link_map *m 3717 * +4 struct r_debug *rd 3718 * +0 RetAddr 3719 */ 3720void 3721r_debug_state(struct r_debug* rd, struct link_map *m) 3722{ 3723 /* 3724 * The following is a hack to force the compiler to emit calls to 3725 * this function, even when optimizing. If the function is empty, 3726 * the compiler is not obliged to emit any code for calls to it, 3727 * even when marked __noinline. However, gdb depends on those 3728 * calls being made. 3729 */ 3730 __compiler_membar(); 3731} 3732 3733/* 3734 * A function called after init routines have completed. This can be used to 3735 * break before a program's entry routine is called, and can be used when 3736 * main is not available in the symbol table. 3737 */ 3738void 3739_r_debug_postinit(struct link_map *m) 3740{ 3741 3742 /* See r_debug_state(). */ 3743 __compiler_membar(); 3744} 3745 3746/* 3747 * Get address of the pointer variable in the main program. 3748 * Prefer non-weak symbol over the weak one. 3749 */ 3750static const void ** 3751get_program_var_addr(const char *name, RtldLockState *lockstate) 3752{ 3753 SymLook req; 3754 DoneList donelist; 3755 3756 symlook_init(&req, name); 3757 req.lockstate = lockstate; 3758 donelist_init(&donelist); 3759 if (symlook_global(&req, &donelist) != 0) 3760 return (NULL); 3761 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3762 return ((const void **)make_function_pointer(req.sym_out, 3763 req.defobj_out)); 3764 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3765 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3766 else 3767 return ((const void **)(req.defobj_out->relocbase + 3768 req.sym_out->st_value)); 3769} 3770 3771/* 3772 * Set a pointer variable in the main program to the given value. This 3773 * is used to set key variables such as "environ" before any of the 3774 * init functions are called. 3775 */ 3776static void 3777set_program_var(const char *name, const void *value) 3778{ 3779 const void **addr; 3780 3781 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3782 dbg("\"%s\": *%p <-- %p", name, addr, value); 3783 *addr = value; 3784 } 3785} 3786 3787/* 3788 * Search the global objects, including dependencies and main object, 3789 * for the given symbol. 3790 */ 3791static int 3792symlook_global(SymLook *req, DoneList *donelist) 3793{ 3794 SymLook req1; 3795 const Objlist_Entry *elm; 3796 int res; 3797 3798 symlook_init_from_req(&req1, req); 3799 3800 /* Search all objects loaded at program start up. */ 3801 if (req->defobj_out == NULL || 3802 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3803 res = symlook_list(&req1, &list_main, donelist); 3804 if (res == 0 && (req->defobj_out == NULL || 3805 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3806 req->sym_out = req1.sym_out; 3807 req->defobj_out = req1.defobj_out; 3808 assert(req->defobj_out != NULL); 3809 } 3810 } 3811 3812 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3813 STAILQ_FOREACH(elm, &list_global, link) { 3814 if (req->defobj_out != NULL && 3815 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3816 break; 3817 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3818 if (res == 0 && (req->defobj_out == NULL || 3819 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3820 req->sym_out = req1.sym_out; 3821 req->defobj_out = req1.defobj_out; 3822 assert(req->defobj_out != NULL); 3823 } 3824 } 3825 3826 return (req->sym_out != NULL ? 0 : ESRCH); 3827} 3828 3829/* 3830 * Given a symbol name in a referencing object, find the corresponding 3831 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3832 * no definition was found. Returns a pointer to the Obj_Entry of the 3833 * defining object via the reference parameter DEFOBJ_OUT. 3834 */ 3835static int 3836symlook_default(SymLook *req, const Obj_Entry *refobj) 3837{ 3838 DoneList donelist; 3839 const Objlist_Entry *elm; 3840 SymLook req1; 3841 int res; 3842 3843 donelist_init(&donelist); 3844 symlook_init_from_req(&req1, req); 3845 3846 /* 3847 * Look first in the referencing object if linked symbolically, 3848 * and similarly handle protected symbols. 3849 */ 3850 res = symlook_obj(&req1, refobj); 3851 if (res == 0 && (refobj->symbolic || 3852 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) { 3853 req->sym_out = req1.sym_out; 3854 req->defobj_out = req1.defobj_out; 3855 assert(req->defobj_out != NULL); 3856 } 3857 if (refobj->symbolic || req->defobj_out != NULL) 3858 donelist_check(&donelist, refobj); 3859 3860 symlook_global(req, &donelist); 3861 3862 /* Search all dlopened DAGs containing the referencing object. */ 3863 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3864 if (req->sym_out != NULL && 3865 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3866 break; 3867 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3868 if (res == 0 && (req->sym_out == NULL || 3869 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3870 req->sym_out = req1.sym_out; 3871 req->defobj_out = req1.defobj_out; 3872 assert(req->defobj_out != NULL); 3873 } 3874 } 3875 3876 /* 3877 * Search the dynamic linker itself, and possibly resolve the 3878 * symbol from there. This is how the application links to 3879 * dynamic linker services such as dlopen. 3880 */ 3881 if (req->sym_out == NULL || 3882 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3883 res = symlook_obj(&req1, &obj_rtld); 3884 if (res == 0) { 3885 req->sym_out = req1.sym_out; 3886 req->defobj_out = req1.defobj_out; 3887 assert(req->defobj_out != NULL); 3888 } 3889 } 3890 3891 return (req->sym_out != NULL ? 0 : ESRCH); 3892} 3893 3894static int 3895symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3896{ 3897 const Elf_Sym *def; 3898 const Obj_Entry *defobj; 3899 const Objlist_Entry *elm; 3900 SymLook req1; 3901 int res; 3902 3903 def = NULL; 3904 defobj = NULL; 3905 STAILQ_FOREACH(elm, objlist, link) { 3906 if (donelist_check(dlp, elm->obj)) 3907 continue; 3908 symlook_init_from_req(&req1, req); 3909 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3910 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3911 def = req1.sym_out; 3912 defobj = req1.defobj_out; 3913 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3914 break; 3915 } 3916 } 3917 } 3918 if (def != NULL) { 3919 req->sym_out = def; 3920 req->defobj_out = defobj; 3921 return (0); 3922 } 3923 return (ESRCH); 3924} 3925 3926/* 3927 * Search the chain of DAGS cointed to by the given Needed_Entry 3928 * for a symbol of the given name. Each DAG is scanned completely 3929 * before advancing to the next one. Returns a pointer to the symbol, 3930 * or NULL if no definition was found. 3931 */ 3932static int 3933symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3934{ 3935 const Elf_Sym *def; 3936 const Needed_Entry *n; 3937 const Obj_Entry *defobj; 3938 SymLook req1; 3939 int res; 3940 3941 def = NULL; 3942 defobj = NULL; 3943 symlook_init_from_req(&req1, req); 3944 for (n = needed; n != NULL; n = n->next) { 3945 if (n->obj == NULL || 3946 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3947 continue; 3948 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3949 def = req1.sym_out; 3950 defobj = req1.defobj_out; 3951 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3952 break; 3953 } 3954 } 3955 if (def != NULL) { 3956 req->sym_out = def; 3957 req->defobj_out = defobj; 3958 return (0); 3959 } 3960 return (ESRCH); 3961} 3962 3963/* 3964 * Search the symbol table of a single shared object for a symbol of 3965 * the given name and version, if requested. Returns a pointer to the 3966 * symbol, or NULL if no definition was found. If the object is 3967 * filter, return filtered symbol from filtee. 3968 * 3969 * The symbol's hash value is passed in for efficiency reasons; that 3970 * eliminates many recomputations of the hash value. 3971 */ 3972int 3973symlook_obj(SymLook *req, const Obj_Entry *obj) 3974{ 3975 DoneList donelist; 3976 SymLook req1; 3977 int flags, res, mres; 3978 3979 /* 3980 * If there is at least one valid hash at this point, we prefer to 3981 * use the faster GNU version if available. 3982 */ 3983 if (obj->valid_hash_gnu) 3984 mres = symlook_obj1_gnu(req, obj); 3985 else if (obj->valid_hash_sysv) 3986 mres = symlook_obj1_sysv(req, obj); 3987 else 3988 return (EINVAL); 3989 3990 if (mres == 0) { 3991 if (obj->needed_filtees != NULL) { 3992 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3993 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3994 donelist_init(&donelist); 3995 symlook_init_from_req(&req1, req); 3996 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3997 if (res == 0) { 3998 req->sym_out = req1.sym_out; 3999 req->defobj_out = req1.defobj_out; 4000 } 4001 return (res); 4002 } 4003 if (obj->needed_aux_filtees != NULL) { 4004 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4005 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4006 donelist_init(&donelist); 4007 symlook_init_from_req(&req1, req); 4008 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4009 if (res == 0) { 4010 req->sym_out = req1.sym_out; 4011 req->defobj_out = req1.defobj_out; 4012 return (res); 4013 } 4014 } 4015 } 4016 return (mres); 4017} 4018 4019/* Symbol match routine common to both hash functions */ 4020static bool 4021matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4022 const unsigned long symnum) 4023{ 4024 Elf_Versym verndx; 4025 const Elf_Sym *symp; 4026 const char *strp; 4027 4028 symp = obj->symtab + symnum; 4029 strp = obj->strtab + symp->st_name; 4030 4031 switch (ELF_ST_TYPE(symp->st_info)) { 4032 case STT_FUNC: 4033 case STT_NOTYPE: 4034 case STT_OBJECT: 4035 case STT_COMMON: 4036 case STT_GNU_IFUNC: 4037 if (symp->st_value == 0) 4038 return (false); 4039 /* fallthrough */ 4040 case STT_TLS: 4041 if (symp->st_shndx != SHN_UNDEF) 4042 break; 4043#ifndef __mips__ 4044 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4045 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4046 break; 4047 /* fallthrough */ 4048#endif 4049 default: 4050 return (false); 4051 } 4052 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4053 return (false); 4054 4055 if (req->ventry == NULL) { 4056 if (obj->versyms != NULL) { 4057 verndx = VER_NDX(obj->versyms[symnum]); 4058 if (verndx > obj->vernum) { 4059 _rtld_error( 4060 "%s: symbol %s references wrong version %d", 4061 obj->path, obj->strtab + symnum, verndx); 4062 return (false); 4063 } 4064 /* 4065 * If we are not called from dlsym (i.e. this 4066 * is a normal relocation from unversioned 4067 * binary), accept the symbol immediately if 4068 * it happens to have first version after this 4069 * shared object became versioned. Otherwise, 4070 * if symbol is versioned and not hidden, 4071 * remember it. If it is the only symbol with 4072 * this name exported by the shared object, it 4073 * will be returned as a match by the calling 4074 * function. If symbol is global (verndx < 2) 4075 * accept it unconditionally. 4076 */ 4077 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4078 verndx == VER_NDX_GIVEN) { 4079 result->sym_out = symp; 4080 return (true); 4081 } 4082 else if (verndx >= VER_NDX_GIVEN) { 4083 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4084 == 0) { 4085 if (result->vsymp == NULL) 4086 result->vsymp = symp; 4087 result->vcount++; 4088 } 4089 return (false); 4090 } 4091 } 4092 result->sym_out = symp; 4093 return (true); 4094 } 4095 if (obj->versyms == NULL) { 4096 if (object_match_name(obj, req->ventry->name)) { 4097 _rtld_error("%s: object %s should provide version %s " 4098 "for symbol %s", obj_rtld.path, obj->path, 4099 req->ventry->name, obj->strtab + symnum); 4100 return (false); 4101 } 4102 } else { 4103 verndx = VER_NDX(obj->versyms[symnum]); 4104 if (verndx > obj->vernum) { 4105 _rtld_error("%s: symbol %s references wrong version %d", 4106 obj->path, obj->strtab + symnum, verndx); 4107 return (false); 4108 } 4109 if (obj->vertab[verndx].hash != req->ventry->hash || 4110 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4111 /* 4112 * Version does not match. Look if this is a 4113 * global symbol and if it is not hidden. If 4114 * global symbol (verndx < 2) is available, 4115 * use it. Do not return symbol if we are 4116 * called by dlvsym, because dlvsym looks for 4117 * a specific version and default one is not 4118 * what dlvsym wants. 4119 */ 4120 if ((req->flags & SYMLOOK_DLSYM) || 4121 (verndx >= VER_NDX_GIVEN) || 4122 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4123 return (false); 4124 } 4125 } 4126 result->sym_out = symp; 4127 return (true); 4128} 4129 4130/* 4131 * Search for symbol using SysV hash function. 4132 * obj->buckets is known not to be NULL at this point; the test for this was 4133 * performed with the obj->valid_hash_sysv assignment. 4134 */ 4135static int 4136symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4137{ 4138 unsigned long symnum; 4139 Sym_Match_Result matchres; 4140 4141 matchres.sym_out = NULL; 4142 matchres.vsymp = NULL; 4143 matchres.vcount = 0; 4144 4145 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4146 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4147 if (symnum >= obj->nchains) 4148 return (ESRCH); /* Bad object */ 4149 4150 if (matched_symbol(req, obj, &matchres, symnum)) { 4151 req->sym_out = matchres.sym_out; 4152 req->defobj_out = obj; 4153 return (0); 4154 } 4155 } 4156 if (matchres.vcount == 1) { 4157 req->sym_out = matchres.vsymp; 4158 req->defobj_out = obj; 4159 return (0); 4160 } 4161 return (ESRCH); 4162} 4163 4164/* Search for symbol using GNU hash function */ 4165static int 4166symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4167{ 4168 Elf_Addr bloom_word; 4169 const Elf32_Word *hashval; 4170 Elf32_Word bucket; 4171 Sym_Match_Result matchres; 4172 unsigned int h1, h2; 4173 unsigned long symnum; 4174 4175 matchres.sym_out = NULL; 4176 matchres.vsymp = NULL; 4177 matchres.vcount = 0; 4178 4179 /* Pick right bitmask word from Bloom filter array */ 4180 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4181 obj->maskwords_bm_gnu]; 4182 4183 /* Calculate modulus word size of gnu hash and its derivative */ 4184 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4185 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4186 4187 /* Filter out the "definitely not in set" queries */ 4188 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4189 return (ESRCH); 4190 4191 /* Locate hash chain and corresponding value element*/ 4192 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4193 if (bucket == 0) 4194 return (ESRCH); 4195 hashval = &obj->chain_zero_gnu[bucket]; 4196 do { 4197 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4198 symnum = hashval - obj->chain_zero_gnu; 4199 if (matched_symbol(req, obj, &matchres, symnum)) { 4200 req->sym_out = matchres.sym_out; 4201 req->defobj_out = obj; 4202 return (0); 4203 } 4204 } 4205 } while ((*hashval++ & 1) == 0); 4206 if (matchres.vcount == 1) { 4207 req->sym_out = matchres.vsymp; 4208 req->defobj_out = obj; 4209 return (0); 4210 } 4211 return (ESRCH); 4212} 4213 4214static void 4215trace_loaded_objects(Obj_Entry *obj) 4216{ 4217 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4218 int c; 4219 4220 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4221 main_local = ""; 4222 4223 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4224 fmt1 = "\t%o => %p (%x)\n"; 4225 4226 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4227 fmt2 = "\t%o (%x)\n"; 4228 4229 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4230 4231 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4232 Needed_Entry *needed; 4233 char *name, *path; 4234 bool is_lib; 4235 4236 if (obj->marker) 4237 continue; 4238 if (list_containers && obj->needed != NULL) 4239 rtld_printf("%s:\n", obj->path); 4240 for (needed = obj->needed; needed; needed = needed->next) { 4241 if (needed->obj != NULL) { 4242 if (needed->obj->traced && !list_containers) 4243 continue; 4244 needed->obj->traced = true; 4245 path = needed->obj->path; 4246 } else 4247 path = "not found"; 4248 4249 name = (char *)obj->strtab + needed->name; 4250 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4251 4252 fmt = is_lib ? fmt1 : fmt2; 4253 while ((c = *fmt++) != '\0') { 4254 switch (c) { 4255 default: 4256 rtld_putchar(c); 4257 continue; 4258 case '\\': 4259 switch (c = *fmt) { 4260 case '\0': 4261 continue; 4262 case 'n': 4263 rtld_putchar('\n'); 4264 break; 4265 case 't': 4266 rtld_putchar('\t'); 4267 break; 4268 } 4269 break; 4270 case '%': 4271 switch (c = *fmt) { 4272 case '\0': 4273 continue; 4274 case '%': 4275 default: 4276 rtld_putchar(c); 4277 break; 4278 case 'A': 4279 rtld_putstr(main_local); 4280 break; 4281 case 'a': 4282 rtld_putstr(obj_main->path); 4283 break; 4284 case 'o': 4285 rtld_putstr(name); 4286 break; 4287#if 0 4288 case 'm': 4289 rtld_printf("%d", sodp->sod_major); 4290 break; 4291 case 'n': 4292 rtld_printf("%d", sodp->sod_minor); 4293 break; 4294#endif 4295 case 'p': 4296 rtld_putstr(path); 4297 break; 4298 case 'x': 4299 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4300 0); 4301 break; 4302 } 4303 break; 4304 } 4305 ++fmt; 4306 } 4307 } 4308 } 4309} 4310 4311/* 4312 * Unload a dlopened object and its dependencies from memory and from 4313 * our data structures. It is assumed that the DAG rooted in the 4314 * object has already been unreferenced, and that the object has a 4315 * reference count of 0. 4316 */ 4317static void 4318unload_object(Obj_Entry *root) 4319{ 4320 Obj_Entry *obj, *obj1; 4321 4322 assert(root->refcount == 0); 4323 4324 /* 4325 * Pass over the DAG removing unreferenced objects from 4326 * appropriate lists. 4327 */ 4328 unlink_object(root); 4329 4330 /* Unmap all objects that are no longer referenced. */ 4331 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) { 4332 if (obj->marker || obj->refcount != 0) 4333 continue; 4334 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, 4335 obj->mapsize, 0, obj->path); 4336 dbg("unloading \"%s\"", obj->path); 4337 unload_filtees(root); 4338 munmap(obj->mapbase, obj->mapsize); 4339 linkmap_delete(obj); 4340 TAILQ_REMOVE(&obj_list, obj, next); 4341 obj_count--; 4342 obj_free(obj); 4343 } 4344} 4345 4346static void 4347unlink_object(Obj_Entry *root) 4348{ 4349 Objlist_Entry *elm; 4350 4351 if (root->refcount == 0) { 4352 /* Remove the object from the RTLD_GLOBAL list. */ 4353 objlist_remove(&list_global, root); 4354 4355 /* Remove the object from all objects' DAG lists. */ 4356 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4357 objlist_remove(&elm->obj->dldags, root); 4358 if (elm->obj != root) 4359 unlink_object(elm->obj); 4360 } 4361 } 4362} 4363 4364static void 4365ref_dag(Obj_Entry *root) 4366{ 4367 Objlist_Entry *elm; 4368 4369 assert(root->dag_inited); 4370 STAILQ_FOREACH(elm, &root->dagmembers, link) 4371 elm->obj->refcount++; 4372} 4373 4374static void 4375unref_dag(Obj_Entry *root) 4376{ 4377 Objlist_Entry *elm; 4378 4379 assert(root->dag_inited); 4380 STAILQ_FOREACH(elm, &root->dagmembers, link) 4381 elm->obj->refcount--; 4382} 4383 4384/* 4385 * Common code for MD __tls_get_addr(). 4386 */ 4387static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4388static void * 4389tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4390{ 4391 Elf_Addr *newdtv, *dtv; 4392 RtldLockState lockstate; 4393 int to_copy; 4394 4395 dtv = *dtvp; 4396 /* Check dtv generation in case new modules have arrived */ 4397 if (dtv[0] != tls_dtv_generation) { 4398 wlock_acquire(rtld_bind_lock, &lockstate); 4399 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4400 to_copy = dtv[1]; 4401 if (to_copy > tls_max_index) 4402 to_copy = tls_max_index; 4403 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4404 newdtv[0] = tls_dtv_generation; 4405 newdtv[1] = tls_max_index; 4406 free(dtv); 4407 lock_release(rtld_bind_lock, &lockstate); 4408 dtv = *dtvp = newdtv; 4409 } 4410 4411 /* Dynamically allocate module TLS if necessary */ 4412 if (dtv[index + 1] == 0) { 4413 /* Signal safe, wlock will block out signals. */ 4414 wlock_acquire(rtld_bind_lock, &lockstate); 4415 if (!dtv[index + 1]) 4416 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4417 lock_release(rtld_bind_lock, &lockstate); 4418 } 4419 return ((void *)(dtv[index + 1] + offset)); 4420} 4421 4422void * 4423tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4424{ 4425 Elf_Addr *dtv; 4426 4427 dtv = *dtvp; 4428 /* Check dtv generation in case new modules have arrived */ 4429 if (__predict_true(dtv[0] == tls_dtv_generation && 4430 dtv[index + 1] != 0)) 4431 return ((void *)(dtv[index + 1] + offset)); 4432 return (tls_get_addr_slow(dtvp, index, offset)); 4433} 4434 4435#if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__) 4436 4437/* 4438 * Allocate Static TLS using the Variant I method. 4439 */ 4440void * 4441allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4442{ 4443 Obj_Entry *obj; 4444 char *tcb; 4445 Elf_Addr **tls; 4446 Elf_Addr *dtv; 4447 Elf_Addr addr; 4448 int i; 4449 4450 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4451 return (oldtcb); 4452 4453 assert(tcbsize >= TLS_TCB_SIZE); 4454 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4455 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4456 4457 if (oldtcb != NULL) { 4458 memcpy(tls, oldtcb, tls_static_space); 4459 free(oldtcb); 4460 4461 /* Adjust the DTV. */ 4462 dtv = tls[0]; 4463 for (i = 0; i < dtv[1]; i++) { 4464 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4465 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4466 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4467 } 4468 } 4469 } else { 4470 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4471 tls[0] = dtv; 4472 dtv[0] = tls_dtv_generation; 4473 dtv[1] = tls_max_index; 4474 4475 for (obj = globallist_curr(objs); obj != NULL; 4476 obj = globallist_next(obj)) { 4477 if (obj->tlsoffset > 0) { 4478 addr = (Elf_Addr)tls + obj->tlsoffset; 4479 if (obj->tlsinitsize > 0) 4480 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4481 if (obj->tlssize > obj->tlsinitsize) 4482 memset((void*) (addr + obj->tlsinitsize), 0, 4483 obj->tlssize - obj->tlsinitsize); 4484 dtv[obj->tlsindex + 1] = addr; 4485 } 4486 } 4487 } 4488 4489 return (tcb); 4490} 4491 4492void 4493free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4494{ 4495 Elf_Addr *dtv; 4496 Elf_Addr tlsstart, tlsend; 4497 int dtvsize, i; 4498 4499 assert(tcbsize >= TLS_TCB_SIZE); 4500 4501 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4502 tlsend = tlsstart + tls_static_space; 4503 4504 dtv = *(Elf_Addr **)tlsstart; 4505 dtvsize = dtv[1]; 4506 for (i = 0; i < dtvsize; i++) { 4507 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4508 free((void*)dtv[i+2]); 4509 } 4510 } 4511 free(dtv); 4512 free(tcb); 4513} 4514 4515#endif 4516 4517#if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4518 4519/* 4520 * Allocate Static TLS using the Variant II method. 4521 */ 4522void * 4523allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4524{ 4525 Obj_Entry *obj; 4526 size_t size, ralign; 4527 char *tls; 4528 Elf_Addr *dtv, *olddtv; 4529 Elf_Addr segbase, oldsegbase, addr; 4530 int i; 4531 4532 ralign = tcbalign; 4533 if (tls_static_max_align > ralign) 4534 ralign = tls_static_max_align; 4535 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4536 4537 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4538 tls = malloc_aligned(size, ralign); 4539 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4540 4541 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4542 ((Elf_Addr*)segbase)[0] = segbase; 4543 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4544 4545 dtv[0] = tls_dtv_generation; 4546 dtv[1] = tls_max_index; 4547 4548 if (oldtls) { 4549 /* 4550 * Copy the static TLS block over whole. 4551 */ 4552 oldsegbase = (Elf_Addr) oldtls; 4553 memcpy((void *)(segbase - tls_static_space), 4554 (const void *)(oldsegbase - tls_static_space), 4555 tls_static_space); 4556 4557 /* 4558 * If any dynamic TLS blocks have been created tls_get_addr(), 4559 * move them over. 4560 */ 4561 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4562 for (i = 0; i < olddtv[1]; i++) { 4563 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4564 dtv[i+2] = olddtv[i+2]; 4565 olddtv[i+2] = 0; 4566 } 4567 } 4568 4569 /* 4570 * We assume that this block was the one we created with 4571 * allocate_initial_tls(). 4572 */ 4573 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4574 } else { 4575 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { 4576 if (obj->marker || obj->tlsoffset == 0) 4577 continue; 4578 addr = segbase - obj->tlsoffset; 4579 memset((void*) (addr + obj->tlsinitsize), 4580 0, obj->tlssize - obj->tlsinitsize); 4581 if (obj->tlsinit) 4582 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4583 dtv[obj->tlsindex + 1] = addr; 4584 } 4585 } 4586 4587 return (void*) segbase; 4588} 4589 4590void 4591free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4592{ 4593 Elf_Addr* dtv; 4594 size_t size, ralign; 4595 int dtvsize, i; 4596 Elf_Addr tlsstart, tlsend; 4597 4598 /* 4599 * Figure out the size of the initial TLS block so that we can 4600 * find stuff which ___tls_get_addr() allocated dynamically. 4601 */ 4602 ralign = tcbalign; 4603 if (tls_static_max_align > ralign) 4604 ralign = tls_static_max_align; 4605 size = round(tls_static_space, ralign); 4606 4607 dtv = ((Elf_Addr**)tls)[1]; 4608 dtvsize = dtv[1]; 4609 tlsend = (Elf_Addr) tls; 4610 tlsstart = tlsend - size; 4611 for (i = 0; i < dtvsize; i++) { 4612 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4613 free_aligned((void *)dtv[i + 2]); 4614 } 4615 } 4616 4617 free_aligned((void *)tlsstart); 4618 free((void*) dtv); 4619} 4620 4621#endif 4622 4623/* 4624 * Allocate TLS block for module with given index. 4625 */ 4626void * 4627allocate_module_tls(int index) 4628{ 4629 Obj_Entry* obj; 4630 char* p; 4631 4632 TAILQ_FOREACH(obj, &obj_list, next) { 4633 if (obj->marker) 4634 continue; 4635 if (obj->tlsindex == index) 4636 break; 4637 } 4638 if (!obj) { 4639 _rtld_error("Can't find module with TLS index %d", index); 4640 rtld_die(); 4641 } 4642 4643 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4644 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4645 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4646 4647 return p; 4648} 4649 4650bool 4651allocate_tls_offset(Obj_Entry *obj) 4652{ 4653 size_t off; 4654 4655 if (obj->tls_done) 4656 return true; 4657 4658 if (obj->tlssize == 0) { 4659 obj->tls_done = true; 4660 return true; 4661 } 4662 4663 if (tls_last_offset == 0) 4664 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4665 else 4666 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4667 obj->tlssize, obj->tlsalign); 4668 4669 /* 4670 * If we have already fixed the size of the static TLS block, we 4671 * must stay within that size. When allocating the static TLS, we 4672 * leave a small amount of space spare to be used for dynamically 4673 * loading modules which use static TLS. 4674 */ 4675 if (tls_static_space != 0) { 4676 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4677 return false; 4678 } else if (obj->tlsalign > tls_static_max_align) { 4679 tls_static_max_align = obj->tlsalign; 4680 } 4681 4682 tls_last_offset = obj->tlsoffset = off; 4683 tls_last_size = obj->tlssize; 4684 obj->tls_done = true; 4685 4686 return true; 4687} 4688 4689void 4690free_tls_offset(Obj_Entry *obj) 4691{ 4692 4693 /* 4694 * If we were the last thing to allocate out of the static TLS 4695 * block, we give our space back to the 'allocator'. This is a 4696 * simplistic workaround to allow libGL.so.1 to be loaded and 4697 * unloaded multiple times. 4698 */ 4699 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4700 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4701 tls_last_offset -= obj->tlssize; 4702 tls_last_size = 0; 4703 } 4704} 4705 4706void * 4707_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4708{ 4709 void *ret; 4710 RtldLockState lockstate; 4711 4712 wlock_acquire(rtld_bind_lock, &lockstate); 4713 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls, 4714 tcbsize, tcbalign); 4715 lock_release(rtld_bind_lock, &lockstate); 4716 return (ret); 4717} 4718 4719void 4720_rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4721{ 4722 RtldLockState lockstate; 4723 4724 wlock_acquire(rtld_bind_lock, &lockstate); 4725 free_tls(tcb, tcbsize, tcbalign); 4726 lock_release(rtld_bind_lock, &lockstate); 4727} 4728 4729static void 4730object_add_name(Obj_Entry *obj, const char *name) 4731{ 4732 Name_Entry *entry; 4733 size_t len; 4734 4735 len = strlen(name); 4736 entry = malloc(sizeof(Name_Entry) + len); 4737 4738 if (entry != NULL) { 4739 strcpy(entry->name, name); 4740 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4741 } 4742} 4743 4744static int 4745object_match_name(const Obj_Entry *obj, const char *name) 4746{ 4747 Name_Entry *entry; 4748 4749 STAILQ_FOREACH(entry, &obj->names, link) { 4750 if (strcmp(name, entry->name) == 0) 4751 return (1); 4752 } 4753 return (0); 4754} 4755 4756static Obj_Entry * 4757locate_dependency(const Obj_Entry *obj, const char *name) 4758{ 4759 const Objlist_Entry *entry; 4760 const Needed_Entry *needed; 4761 4762 STAILQ_FOREACH(entry, &list_main, link) { 4763 if (object_match_name(entry->obj, name)) 4764 return entry->obj; 4765 } 4766 4767 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4768 if (strcmp(obj->strtab + needed->name, name) == 0 || 4769 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4770 /* 4771 * If there is DT_NEEDED for the name we are looking for, 4772 * we are all set. Note that object might not be found if 4773 * dependency was not loaded yet, so the function can 4774 * return NULL here. This is expected and handled 4775 * properly by the caller. 4776 */ 4777 return (needed->obj); 4778 } 4779 } 4780 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4781 obj->path, name); 4782 rtld_die(); 4783} 4784 4785static int 4786check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4787 const Elf_Vernaux *vna) 4788{ 4789 const Elf_Verdef *vd; 4790 const char *vername; 4791 4792 vername = refobj->strtab + vna->vna_name; 4793 vd = depobj->verdef; 4794 if (vd == NULL) { 4795 _rtld_error("%s: version %s required by %s not defined", 4796 depobj->path, vername, refobj->path); 4797 return (-1); 4798 } 4799 for (;;) { 4800 if (vd->vd_version != VER_DEF_CURRENT) { 4801 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4802 depobj->path, vd->vd_version); 4803 return (-1); 4804 } 4805 if (vna->vna_hash == vd->vd_hash) { 4806 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4807 ((char *)vd + vd->vd_aux); 4808 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4809 return (0); 4810 } 4811 if (vd->vd_next == 0) 4812 break; 4813 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4814 } 4815 if (vna->vna_flags & VER_FLG_WEAK) 4816 return (0); 4817 _rtld_error("%s: version %s required by %s not found", 4818 depobj->path, vername, refobj->path); 4819 return (-1); 4820} 4821 4822static int 4823rtld_verify_object_versions(Obj_Entry *obj) 4824{ 4825 const Elf_Verneed *vn; 4826 const Elf_Verdef *vd; 4827 const Elf_Verdaux *vda; 4828 const Elf_Vernaux *vna; 4829 const Obj_Entry *depobj; 4830 int maxvernum, vernum; 4831 4832 if (obj->ver_checked) 4833 return (0); 4834 obj->ver_checked = true; 4835 4836 maxvernum = 0; 4837 /* 4838 * Walk over defined and required version records and figure out 4839 * max index used by any of them. Do very basic sanity checking 4840 * while there. 4841 */ 4842 vn = obj->verneed; 4843 while (vn != NULL) { 4844 if (vn->vn_version != VER_NEED_CURRENT) { 4845 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4846 obj->path, vn->vn_version); 4847 return (-1); 4848 } 4849 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4850 for (;;) { 4851 vernum = VER_NEED_IDX(vna->vna_other); 4852 if (vernum > maxvernum) 4853 maxvernum = vernum; 4854 if (vna->vna_next == 0) 4855 break; 4856 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4857 } 4858 if (vn->vn_next == 0) 4859 break; 4860 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4861 } 4862 4863 vd = obj->verdef; 4864 while (vd != NULL) { 4865 if (vd->vd_version != VER_DEF_CURRENT) { 4866 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4867 obj->path, vd->vd_version); 4868 return (-1); 4869 } 4870 vernum = VER_DEF_IDX(vd->vd_ndx); 4871 if (vernum > maxvernum) 4872 maxvernum = vernum; 4873 if (vd->vd_next == 0) 4874 break; 4875 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4876 } 4877 4878 if (maxvernum == 0) 4879 return (0); 4880 4881 /* 4882 * Store version information in array indexable by version index. 4883 * Verify that object version requirements are satisfied along the 4884 * way. 4885 */ 4886 obj->vernum = maxvernum + 1; 4887 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4888 4889 vd = obj->verdef; 4890 while (vd != NULL) { 4891 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4892 vernum = VER_DEF_IDX(vd->vd_ndx); 4893 assert(vernum <= maxvernum); 4894 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4895 obj->vertab[vernum].hash = vd->vd_hash; 4896 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4897 obj->vertab[vernum].file = NULL; 4898 obj->vertab[vernum].flags = 0; 4899 } 4900 if (vd->vd_next == 0) 4901 break; 4902 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4903 } 4904 4905 vn = obj->verneed; 4906 while (vn != NULL) { 4907 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4908 if (depobj == NULL) 4909 return (-1); 4910 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4911 for (;;) { 4912 if (check_object_provided_version(obj, depobj, vna)) 4913 return (-1); 4914 vernum = VER_NEED_IDX(vna->vna_other); 4915 assert(vernum <= maxvernum); 4916 obj->vertab[vernum].hash = vna->vna_hash; 4917 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4918 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4919 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4920 VER_INFO_HIDDEN : 0; 4921 if (vna->vna_next == 0) 4922 break; 4923 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4924 } 4925 if (vn->vn_next == 0) 4926 break; 4927 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4928 } 4929 return 0; 4930} 4931 4932static int 4933rtld_verify_versions(const Objlist *objlist) 4934{ 4935 Objlist_Entry *entry; 4936 int rc; 4937 4938 rc = 0; 4939 STAILQ_FOREACH(entry, objlist, link) { 4940 /* 4941 * Skip dummy objects or objects that have their version requirements 4942 * already checked. 4943 */ 4944 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4945 continue; 4946 if (rtld_verify_object_versions(entry->obj) == -1) { 4947 rc = -1; 4948 if (ld_tracing == NULL) 4949 break; 4950 } 4951 } 4952 if (rc == 0 || ld_tracing != NULL) 4953 rc = rtld_verify_object_versions(&obj_rtld); 4954 return rc; 4955} 4956 4957const Ver_Entry * 4958fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4959{ 4960 Elf_Versym vernum; 4961 4962 if (obj->vertab) { 4963 vernum = VER_NDX(obj->versyms[symnum]); 4964 if (vernum >= obj->vernum) { 4965 _rtld_error("%s: symbol %s has wrong verneed value %d", 4966 obj->path, obj->strtab + symnum, vernum); 4967 } else if (obj->vertab[vernum].hash != 0) { 4968 return &obj->vertab[vernum]; 4969 } 4970 } 4971 return NULL; 4972} 4973 4974int 4975_rtld_get_stack_prot(void) 4976{ 4977 4978 return (stack_prot); 4979} 4980 4981int 4982_rtld_is_dlopened(void *arg) 4983{ 4984 Obj_Entry *obj; 4985 RtldLockState lockstate; 4986 int res; 4987 4988 rlock_acquire(rtld_bind_lock, &lockstate); 4989 obj = dlcheck(arg); 4990 if (obj == NULL) 4991 obj = obj_from_addr(arg); 4992 if (obj == NULL) { 4993 _rtld_error("No shared object contains address"); 4994 lock_release(rtld_bind_lock, &lockstate); 4995 return (-1); 4996 } 4997 res = obj->dlopened ? 1 : 0; 4998 lock_release(rtld_bind_lock, &lockstate); 4999 return (res); 5000} 5001 5002int 5003obj_enforce_relro(Obj_Entry *obj) 5004{ 5005 5006 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size, 5007 PROT_READ) == -1) { 5008 _rtld_error("%s: Cannot enforce relro protection: %s", 5009 obj->path, rtld_strerror(errno)); 5010 return (-1); 5011 } 5012 return (0); 5013} 5014 5015static void 5016map_stacks_exec(RtldLockState *lockstate) 5017{ 5018 void (*thr_map_stacks_exec)(void); 5019 5020 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 5021 return; 5022 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 5023 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 5024 if (thr_map_stacks_exec != NULL) { 5025 stack_prot |= PROT_EXEC; 5026 thr_map_stacks_exec(); 5027 } 5028} 5029 5030void 5031symlook_init(SymLook *dst, const char *name) 5032{ 5033 5034 bzero(dst, sizeof(*dst)); 5035 dst->name = name; 5036 dst->hash = elf_hash(name); 5037 dst->hash_gnu = gnu_hash(name); 5038} 5039 5040static void 5041symlook_init_from_req(SymLook *dst, const SymLook *src) 5042{ 5043 5044 dst->name = src->name; 5045 dst->hash = src->hash; 5046 dst->hash_gnu = src->hash_gnu; 5047 dst->ventry = src->ventry; 5048 dst->flags = src->flags; 5049 dst->defobj_out = NULL; 5050 dst->sym_out = NULL; 5051 dst->lockstate = src->lockstate; 5052} 5053 5054/* 5055 * Overrides for libc_pic-provided functions. 5056 */ 5057 5058int 5059__getosreldate(void) 5060{ 5061 size_t len; 5062 int oid[2]; 5063 int error, osrel; 5064 5065 if (osreldate != 0) 5066 return (osreldate); 5067 5068 oid[0] = CTL_KERN; 5069 oid[1] = KERN_OSRELDATE; 5070 osrel = 0; 5071 len = sizeof(osrel); 5072 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5073 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5074 osreldate = osrel; 5075 return (osreldate); 5076} 5077 5078void 5079exit(int status) 5080{ 5081 5082 _exit(status); 5083} 5084 5085void (*__cleanup)(void); 5086int __isthreaded = 0; 5087int _thread_autoinit_dummy_decl = 1; 5088 5089/* 5090 * No unresolved symbols for rtld. 5091 */ 5092void 5093__pthread_cxa_finalize(struct dl_phdr_info *a) 5094{ 5095} 5096 5097void 5098__stack_chk_fail(void) 5099{ 5100 5101 _rtld_error("stack overflow detected; terminated"); 5102 rtld_die(); 5103} 5104__weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5105 5106void 5107__chk_fail(void) 5108{ 5109 5110 _rtld_error("buffer overflow detected; terminated"); 5111 rtld_die(); 5112} 5113 5114const char * 5115rtld_strerror(int errnum) 5116{ 5117 5118 if (errnum < 0 || errnum >= sys_nerr) 5119 return ("Unknown error"); 5120 return (sys_errlist[errnum]); 5121} 5122