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 * $FreeBSD$ 29 */ 30 31 /* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37 #ifndef __GNUC__ 38 #error "GCC is needed to compile this file" 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/mount.h> 43 #include <sys/mman.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/uio.h> 47 #include <sys/utsname.h> 48 #include <sys/ktrace.h> 49 #include <sys/resident.h> 50 #include <sys/tls.h> 51 52 #include <machine/tls.h> 53 54 #include <dlfcn.h> 55 #include <err.h> 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <stdarg.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 64 #include "debug.h" 65 #include "rtld.h" 66 #include "libmap.h" 67 #include "rtld_printf.h" 68 #include "notes.h" 69 70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2" 71 #define LD_ARY_CACHE 16 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 /* 78 * Function declarations. 79 */ 80 static const char *_getenv_ld(const char *id); 81 static void die(void) __dead2; 82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 83 const Elf_Dyn **, const Elf_Dyn **); 84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 85 const Elf_Dyn *); 86 static void digest_dynamic(Obj_Entry *, int); 87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 88 static void distribute_static_tls(Objlist *, RtldLockState *); 89 static Obj_Entry *dlcheck(void *); 90 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 91 int lo_flags, int mode, RtldLockState *lockstate); 92 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 93 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 94 static bool donelist_check(DoneList *, const Obj_Entry *); 95 static void errmsg_restore(char *); 96 static char *errmsg_save(void); 97 static void *fill_search_info(const char *, size_t, void *); 98 static char *find_library(const char *, const Obj_Entry *, int *); 99 static const char *gethints(bool); 100 static void init_dag(Obj_Entry *); 101 static void init_rtld(caddr_t, Elf_Auxinfo **); 102 static void initlist_add_neededs(Needed_Entry *, Objlist *); 103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 104 static void linkmap_add(Obj_Entry *); 105 static void linkmap_delete(Obj_Entry *); 106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 107 static void unload_filtees(Obj_Entry *); 108 static int load_needed_objects(Obj_Entry *, int); 109 static int load_preload_objects(void); 110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 111 static void map_stacks_exec(RtldLockState *); 112 static Obj_Entry *obj_from_addr(const void *); 113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 114 static void objlist_call_init(Objlist *, RtldLockState *); 115 static void objlist_clear(Objlist *); 116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 117 static void objlist_init(Objlist *); 118 static void objlist_push_head(Objlist *, Obj_Entry *); 119 static void objlist_push_tail(Objlist *, Obj_Entry *); 120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 121 static void objlist_remove(Objlist *, Obj_Entry *); 122 static int parse_libdir(const char *); 123 static void *path_enumerate(const char *, path_enum_proc, void *); 124 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 125 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 126 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 127 int flags, RtldLockState *lockstate); 128 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 129 RtldLockState *); 130 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 131 int flags, RtldLockState *lockstate); 132 static int rtld_dirname(const char *, char *); 133 static int rtld_dirname_abs(const char *, char *); 134 static void *rtld_dlopen(const char *name, int fd, int mode); 135 static void rtld_exit(void); 136 static char *search_library_path(const char *, const char *); 137 static char *search_library_pathfds(const char *, const char *, int *); 138 static const void **get_program_var_addr(const char *, RtldLockState *); 139 static void set_program_var(const char *, const void *); 140 static int symlook_default(SymLook *, const Obj_Entry *refobj); 141 static int symlook_global(SymLook *, DoneList *); 142 static void symlook_init_from_req(SymLook *, const SymLook *); 143 static int symlook_list(SymLook *, const Objlist *, DoneList *); 144 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 145 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 146 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 147 static void trace_loaded_objects(Obj_Entry *); 148 static void unlink_object(Obj_Entry *); 149 static void unload_object(Obj_Entry *); 150 static void unref_dag(Obj_Entry *); 151 static void ref_dag(Obj_Entry *); 152 static char *origin_subst_one(char *, const char *, const char *, bool); 153 static char *origin_subst(char *, const char *); 154 static void preinit_main(void); 155 static int rtld_verify_versions(const Objlist *); 156 static int rtld_verify_object_versions(Obj_Entry *); 157 static void object_add_name(Obj_Entry *, const char *); 158 static int object_match_name(const Obj_Entry *, const char *); 159 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 160 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 161 struct dl_phdr_info *phdr_info); 162 static uint_fast32_t gnu_hash (const char *); 163 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 164 const unsigned long); 165 166 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 167 void _r_debug_postinit(struct link_map *) __noinline; 168 169 /* 170 * Data declarations. 171 */ 172 static char *error_message; /* Message for dlerror(), or NULL */ 173 struct r_debug r_debug; /* for GDB; */ 174 static bool libmap_disable; /* Disable libmap */ 175 static bool ld_loadfltr; /* Immediate filters processing */ 176 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 177 static bool trust; /* False for setuid and setgid programs */ 178 static bool dangerous_ld_env; /* True if environment variables have been 179 used to affect the libraries loaded */ 180 static const char *ld_bind_now; /* Environment variable for immediate binding */ 181 static const char *ld_debug; /* Environment variable for debugging */ 182 static const char *ld_library_path; /* Environment variable for search path */ 183 static const char *ld_library_dirs; /* Env variable for library descriptors */ 184 static char *ld_preload; /* Environment variable for libraries to 185 load first */ 186 static const char *ld_elf_hints_path; /* Env var. for alternative hints path */ 187 static const char *ld_tracing; /* Called from ldd to print libs */ 188 static const char *ld_utrace; /* Use utrace() to log events. */ 189 static int (*rtld_functrace)( /* Optional function call tracing hook */ 190 const char *caller_obj, 191 const char *callee_obj, 192 const char *callee_func, 193 void *stack); 194 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */ 195 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 196 static Obj_Entry **obj_tail; /* Link field of last object in list */ 197 static Obj_Entry **preload_tail; 198 static Obj_Entry *obj_main; /* The main program shared object */ 199 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 200 static unsigned int obj_count; /* Number of objects in obj_list */ 201 static unsigned int obj_loads; /* Number of objects in obj_list */ 202 203 static int ld_resident; /* Non-zero if resident */ 204 static const char *ld_ary[LD_ARY_CACHE]; 205 static int ld_index; 206 static Objlist initlist; 207 208 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 209 STAILQ_HEAD_INITIALIZER(list_global); 210 static Objlist list_main = /* Objects loaded at program startup */ 211 STAILQ_HEAD_INITIALIZER(list_main); 212 static Objlist list_fini = /* Objects needing fini() calls */ 213 STAILQ_HEAD_INITIALIZER(list_fini); 214 215 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 216 const char *__ld_sharedlib_base; 217 218 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 219 220 extern Elf_Dyn _DYNAMIC; 221 #pragma weak _DYNAMIC 222 #ifndef RTLD_IS_DYNAMIC 223 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 224 #endif 225 226 #ifdef ENABLE_OSRELDATE 227 int osreldate; 228 #endif 229 230 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 231 #if 0 232 static int max_stack_flags; 233 #endif 234 235 /* 236 * Global declarations normally provided by crt1. The dynamic linker is 237 * not built with crt1, so we have to provide them ourselves. 238 */ 239 char *__progname; 240 char **environ; 241 242 /* 243 * Used to pass argc, argv to init functions. 244 */ 245 int main_argc; 246 char **main_argv; 247 248 /* 249 * Globals to control TLS allocation. 250 */ 251 size_t tls_last_offset; /* Static TLS offset of last module */ 252 size_t tls_last_size; /* Static TLS size of last module */ 253 size_t tls_static_space; /* Static TLS space allocated */ 254 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 255 int tls_max_index = 1; /* Largest module index allocated */ 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 10 278 279 struct utrace_rtld { 280 char sig[4]; /* 'RTLD' */ 281 int event; 282 void *handle; 283 void *mapbase; /* Used for 'parent' and 'init/fini' */ 284 size_t mapsize; 285 int refcnt; /* Used for 'mode' */ 286 char name[MAXPATHLEN]; 287 }; 288 289 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 290 if (ld_utrace != NULL) \ 291 ld_utrace_log(e, h, mb, ms, r, n); \ 292 } while (0) 293 294 static void 295 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 296 int refcnt, const char *name) 297 { 298 struct utrace_rtld ut; 299 300 ut.sig[0] = 'R'; 301 ut.sig[1] = 'T'; 302 ut.sig[2] = 'L'; 303 ut.sig[3] = 'D'; 304 ut.event = event; 305 ut.handle = handle; 306 ut.mapbase = mapbase; 307 ut.mapsize = mapsize; 308 ut.refcnt = refcnt; 309 bzero(ut.name, sizeof(ut.name)); 310 if (name) 311 strlcpy(ut.name, name, sizeof(ut.name)); 312 utrace(&ut, sizeof(ut)); 313 } 314 315 /* 316 * Main entry point for dynamic linking. The first argument is the 317 * stack pointer. The stack is expected to be laid out as described 318 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 319 * Specifically, the stack pointer points to a word containing 320 * ARGC. Following that in the stack is a null-terminated sequence 321 * of pointers to argument strings. Then comes a null-terminated 322 * sequence of pointers to environment strings. Finally, there is a 323 * sequence of "auxiliary vector" entries. 324 * 325 * The second argument points to a place to store the dynamic linker's 326 * exit procedure pointer and the third to a place to store the main 327 * program's object. 328 * 329 * The return value is the main program's entry point. 330 */ 331 func_ptr_type 332 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 333 { 334 Elf_Auxinfo *aux_info[AT_COUNT]; 335 int i; 336 int argc; 337 char **argv; 338 char **env; 339 Elf_Auxinfo *aux; 340 Elf_Auxinfo *auxp; 341 const char *argv0; 342 Objlist_Entry *entry; 343 Obj_Entry *obj; 344 Obj_Entry *last_interposer; 345 346 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 347 Obj_Entry **preload_tail; 348 Objlist initlist; 349 from global to here. It will break the DWARF2 unwind scheme. 350 */ 351 352 /* 353 * On entry, the dynamic linker itself has not been relocated yet. 354 * Be very careful not to reference any global data until after 355 * init_rtld has returned. It is OK to reference file-scope statics 356 * and string constants, and to call static and global functions. 357 */ 358 359 /* Find the auxiliary vector on the stack. */ 360 argc = *sp++; 361 argv = (char **) sp; 362 sp += argc + 1; /* Skip over arguments and NULL terminator */ 363 env = (char **) sp; 364 365 /* 366 * If we aren't already resident we have to dig out some more info. 367 * Note that auxinfo does not exist when we are resident. 368 * 369 * I'm not sure about the ld_resident check. It seems to read zero 370 * prior to relocation, which is what we want. When running from a 371 * resident copy everything will be relocated so we are definitely 372 * good there. 373 */ 374 if (ld_resident == 0) { 375 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 376 ; 377 aux = (Elf_Auxinfo *) sp; 378 379 /* Digest the auxiliary vector. */ 380 for (i = 0; i < AT_COUNT; i++) 381 aux_info[i] = NULL; 382 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 383 if (auxp->a_type < AT_COUNT) 384 aux_info[auxp->a_type] = auxp; 385 } 386 387 /* Initialize and relocate ourselves. */ 388 assert(aux_info[AT_BASE] != NULL); 389 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 390 } 391 392 ld_index = 0; /* don't use old env cache in case we are resident */ 393 __progname = obj_rtld.path; 394 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 395 environ = env; 396 main_argc = argc; 397 main_argv = argv; 398 399 trust = !issetugid(); 400 401 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 402 /* 403 * If the process is tainted, then we un-set the dangerous environment 404 * variables. The process will be marked as tainted until setuid(2) 405 * is called. If any child process calls setuid(2) we do not want any 406 * future processes to honor the potentially un-safe variables. 407 */ 408 if (!trust) { 409 if ( unsetenv("LD_DEBUG") 410 || unsetenv("LD_PRELOAD") 411 || unsetenv("LD_LIBRARY_PATH") 412 || unsetenv("LD_LIBRARY_PATH_FDS") 413 || unsetenv("LD_ELF_HINTS_PATH") 414 || unsetenv("LD_LIBMAP") 415 || unsetenv("LD_LIBMAP_DISABLE") 416 || unsetenv("LD_LOADFLTR") 417 || unsetenv("LD_SHAREDLIB_BASE") 418 ) { 419 _rtld_error("environment corrupt; aborting"); 420 die(); 421 } 422 } 423 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE"); 424 ld_debug = _getenv_ld("LD_DEBUG"); 425 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 426 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 427 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 428 ld_library_dirs = _getenv_ld("LD_LIBRARY_PATH_FDS"); 429 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 430 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 431 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL; 432 dangerous_ld_env = (ld_library_path != NULL) 433 || (ld_preload != NULL) 434 || (ld_elf_hints_path != NULL) 435 || ld_loadfltr 436 || (libmap_override != NULL) 437 || libmap_disable 438 ; 439 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 440 ld_utrace = _getenv_ld("LD_UTRACE"); 441 442 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 443 ld_elf_hints_path = _PATH_ELF_HINTS; 444 445 if (ld_debug != NULL && *ld_debug != '\0') 446 debug = 1; 447 dbg("%s is initialized, base address = %p", __progname, 448 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 449 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 450 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 451 452 dbg("initializing thread locks"); 453 lockdflt_init(); 454 455 /* 456 * If we are resident we can skip work that we have already done. 457 * Note that the stack is reset and there is no Elf_Auxinfo 458 * when running from a resident image, and the static globals setup 459 * between here and resident_skip will have already been setup. 460 */ 461 if (ld_resident) 462 goto resident_skip1; 463 464 /* 465 * Load the main program, or process its program header if it is 466 * already loaded. 467 */ 468 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 469 int fd = aux_info[AT_EXECFD]->a_un.a_val; 470 dbg("loading main program"); 471 obj_main = map_object(fd, argv0, NULL); 472 close(fd); 473 if (obj_main == NULL) 474 die(); 475 #if 0 476 max_stack_flags = obj_main->stack_flags; 477 #endif 478 } else { /* Main program already loaded. */ 479 const Elf_Phdr *phdr; 480 int phnum; 481 caddr_t entry; 482 483 dbg("processing main program's program header"); 484 assert(aux_info[AT_PHDR] != NULL); 485 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 486 assert(aux_info[AT_PHNUM] != NULL); 487 phnum = aux_info[AT_PHNUM]->a_un.a_val; 488 assert(aux_info[AT_PHENT] != NULL); 489 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 490 assert(aux_info[AT_ENTRY] != NULL); 491 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 492 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 493 die(); 494 } 495 496 char buf[MAXPATHLEN]; 497 if (aux_info[AT_EXECPATH] != NULL) { 498 char *kexecpath; 499 500 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 501 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 502 if (kexecpath[0] == '/') 503 obj_main->path = kexecpath; 504 else if (getcwd(buf, sizeof(buf)) == NULL || 505 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 506 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 507 obj_main->path = xstrdup(argv0); 508 else 509 obj_main->path = xstrdup(buf); 510 } else { 511 char resolved[MAXPATHLEN]; 512 dbg("No AT_EXECPATH"); 513 if (argv0[0] == '/') { 514 if (realpath(argv0, resolved) != NULL) 515 obj_main->path = xstrdup(resolved); 516 else 517 obj_main->path = xstrdup(argv0); 518 } else { 519 if (getcwd(buf, sizeof(buf)) != NULL 520 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 521 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 522 && access(buf, R_OK) == 0 523 && realpath(buf, resolved) != NULL) 524 obj_main->path = xstrdup(resolved); 525 else 526 obj_main->path = xstrdup(argv0); 527 } 528 } 529 dbg("obj_main path %s", obj_main->path); 530 obj_main->mainprog = true; 531 532 if (aux_info[AT_STACKPROT] != NULL && 533 aux_info[AT_STACKPROT]->a_un.a_val != 0) 534 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 535 536 /* 537 * Get the actual dynamic linker pathname from the executable if 538 * possible. (It should always be possible.) That ensures that 539 * gdb will find the right dynamic linker even if a non-standard 540 * one is being used. 541 */ 542 if (obj_main->interp != NULL && 543 strcmp(obj_main->interp, obj_rtld.path) != 0) { 544 free(obj_rtld.path); 545 obj_rtld.path = xstrdup(obj_main->interp); 546 __progname = obj_rtld.path; 547 } 548 549 digest_dynamic(obj_main, 0); 550 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 551 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 552 obj_main->dynsymcount); 553 554 linkmap_add(obj_main); 555 linkmap_add(&obj_rtld); 556 557 /* Link the main program into the list of objects. */ 558 *obj_tail = obj_main; 559 obj_tail = &obj_main->next; 560 obj_count++; 561 obj_loads++; 562 563 /* Initialize a fake symbol for resolving undefined weak references. */ 564 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 565 sym_zero.st_shndx = SHN_UNDEF; 566 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 567 568 if (!libmap_disable) 569 libmap_disable = (bool)lm_init(libmap_override); 570 571 dbg("loading LD_PRELOAD libraries"); 572 if (load_preload_objects() == -1) 573 die(); 574 preload_tail = obj_tail; 575 576 dbg("loading needed objects"); 577 if (load_needed_objects(obj_main, 0) == -1) 578 die(); 579 580 /* Make a list of all objects loaded at startup. */ 581 last_interposer = obj_main; 582 for (obj = obj_list; obj != NULL; obj = obj->next) { 583 if (obj->z_interpose && obj != obj_main) { 584 objlist_put_after(&list_main, last_interposer, obj); 585 last_interposer = obj; 586 } else { 587 objlist_push_tail(&list_main, obj); 588 } 589 obj->refcount++; 590 } 591 592 dbg("checking for required versions"); 593 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 594 die(); 595 596 resident_skip1: 597 598 if (ld_tracing) { /* We're done */ 599 trace_loaded_objects(obj_main); 600 exit(0); 601 } 602 603 if (ld_resident) /* XXX clean this up! */ 604 goto resident_skip2; 605 606 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 607 dump_relocations(obj_main); 608 exit (0); 609 } 610 611 /* setup TLS for main thread */ 612 dbg("initializing initial thread local storage"); 613 STAILQ_FOREACH(entry, &list_main, link) { 614 /* 615 * Allocate all the initial objects out of the static TLS 616 * block even if they didn't ask for it. 617 */ 618 allocate_tls_offset(entry->obj); 619 } 620 621 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 622 623 /* 624 * Do not try to allocate the TLS here, let libc do it itself. 625 * (crt1 for the program will call _init_tls()) 626 */ 627 628 if (relocate_objects(obj_main, 629 ld_bind_now != NULL && *ld_bind_now != '\0', 630 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 631 die(); 632 633 dbg("doing copy relocations"); 634 if (do_copy_relocations(obj_main) == -1) 635 die(); 636 637 resident_skip2: 638 639 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 640 if (exec_sys_unregister(-1) < 0) { 641 dbg("exec_sys_unregister failed %d\n", errno); 642 exit(errno); 643 } 644 dbg("exec_sys_unregister success\n"); 645 exit(0); 646 } 647 648 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 649 dump_relocations(obj_main); 650 exit (0); 651 } 652 653 dbg("initializing key program variables"); 654 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 655 set_program_var("environ", env); 656 set_program_var("__elf_aux_vector", aux); 657 658 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 659 extern void resident_start(void); 660 ld_resident = 1; 661 if (exec_sys_register(resident_start) < 0) { 662 dbg("exec_sys_register failed %d\n", errno); 663 exit(errno); 664 } 665 dbg("exec_sys_register success\n"); 666 exit(0); 667 } 668 669 /* Make a list of init functions to call. */ 670 objlist_init(&initlist); 671 initlist_add_objects(obj_list, preload_tail, &initlist); 672 673 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 674 675 map_stacks_exec(NULL); 676 677 dbg("resolving ifuncs"); 678 { 679 RtldLockState lockstate; 680 681 wlock_acquire(rtld_bind_lock, &lockstate); 682 if (resolve_objects_ifunc( 683 obj_main, 684 (ld_bind_now != NULL && *ld_bind_now != '\0'), 685 SYMLOOK_EARLY, 686 &lockstate) == -1) { 687 die(); 688 } 689 lock_release(rtld_bind_lock, &lockstate); 690 } 691 692 /* 693 * Do NOT call the initlist here, give libc a chance to set up 694 * the initial TLS segment. crt1 will then call _rtld_call_init(). 695 */ 696 697 dbg("transferring control to program entry point = %p", obj_main->entry); 698 699 /* Return the exit procedure and the program entry point. */ 700 *exit_proc = rtld_exit; 701 *objp = obj_main; 702 return (func_ptr_type) obj_main->entry; 703 } 704 705 /* 706 * Call the initialization list for dynamically loaded libraries. 707 * (called from crt1.c). 708 */ 709 void 710 _rtld_call_init(void) 711 { 712 RtldLockState lockstate; 713 Obj_Entry *obj; 714 715 if (!obj_main->note_present && obj_main->valid_hash_gnu) { 716 /* 717 * The use of a linker script with a PHDRS directive that does not include 718 * PT_NOTE will block the crt_no_init note. In this case we'll look for the 719 * recently added GNU hash dynamic tag which gets built by default. It is 720 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and 721 * a gnu hash tag. If gnu hash found, consider binary to use new crt code. 722 */ 723 obj_main->crt_no_init = true; 724 dbg("Setting crt_no_init without presence of PT_NOTE header"); 725 } 726 727 wlock_acquire(rtld_bind_lock, &lockstate); 728 if (obj_main->crt_no_init) 729 preinit_main(); 730 else { 731 /* 732 * Make sure we don't call the main program's init and fini functions 733 * for binaries linked with old crt1 which calls _init itself. 734 */ 735 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 736 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL; 737 } 738 objlist_call_init(&initlist, &lockstate); 739 _r_debug_postinit(&obj_main->linkmap); 740 objlist_clear(&initlist); 741 dbg("loading filtees"); 742 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 743 if (ld_loadfltr || obj->z_loadfltr) 744 load_filtees(obj, 0, &lockstate); 745 } 746 lock_release(rtld_bind_lock, &lockstate); 747 } 748 749 void * 750 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 751 { 752 void *ptr; 753 Elf_Addr target; 754 755 ptr = (void *)make_function_pointer(def, obj); 756 target = ((Elf_Addr (*)(void))ptr)(); 757 return ((void *)target); 758 } 759 760 Elf_Addr 761 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 762 { 763 const Elf_Rel *rel; 764 const Elf_Sym *def; 765 const Obj_Entry *defobj; 766 Elf_Addr *where; 767 Elf_Addr target; 768 RtldLockState lockstate; 769 770 rlock_acquire(rtld_bind_lock, &lockstate); 771 if (sigsetjmp(lockstate.env, 0) != 0) 772 lock_upgrade(rtld_bind_lock, &lockstate); 773 if (obj->pltrel) 774 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 775 else 776 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 777 778 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 779 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 780 &lockstate); 781 if (def == NULL) 782 die(); 783 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 784 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 785 else 786 target = (Elf_Addr)(defobj->relocbase + def->st_value); 787 788 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 789 defobj->strtab + def->st_name, basename(obj->path), 790 (void *)target, basename(defobj->path)); 791 792 /* 793 * If we have a function call tracing hook, and the 794 * hook would like to keep tracing this one function, 795 * prevent the relocation so we will wind up here 796 * the next time again. 797 * 798 * We don't want to functrace calls from the functracer 799 * to avoid recursive loops. 800 */ 801 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 802 if (rtld_functrace(obj->path, 803 defobj->path, 804 defobj->strtab + def->st_name, 805 stack)) { 806 lock_release(rtld_bind_lock, &lockstate); 807 return target; 808 } 809 } 810 811 /* 812 * Write the new contents for the jmpslot. Note that depending on 813 * architecture, the value which we need to return back to the 814 * lazy binding trampoline may or may not be the target 815 * address. The value returned from reloc_jmpslot() is the value 816 * that the trampoline needs. 817 */ 818 target = reloc_jmpslot(where, target, defobj, obj, rel); 819 lock_release(rtld_bind_lock, &lockstate); 820 return target; 821 } 822 823 /* 824 * Error reporting function. Use it like printf. If formats the message 825 * into a buffer, and sets things up so that the next call to dlerror() 826 * will return the message. 827 */ 828 void 829 _rtld_error(const char *fmt, ...) 830 { 831 static char buf[512]; 832 va_list ap; 833 834 va_start(ap, fmt); 835 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 836 error_message = buf; 837 va_end(ap); 838 } 839 840 /* 841 * Return a dynamically-allocated copy of the current error message, if any. 842 */ 843 static char * 844 errmsg_save(void) 845 { 846 return error_message == NULL ? NULL : xstrdup(error_message); 847 } 848 849 /* 850 * Restore the current error message from a copy which was previously saved 851 * by errmsg_save(). The copy is freed. 852 */ 853 static void 854 errmsg_restore(char *saved_msg) 855 { 856 if (saved_msg == NULL) 857 error_message = NULL; 858 else { 859 _rtld_error("%s", saved_msg); 860 free(saved_msg); 861 } 862 } 863 864 const char * 865 basename(const char *name) 866 { 867 const char *p = strrchr(name, '/'); 868 return p != NULL ? p + 1 : name; 869 } 870 871 static struct utsname uts; 872 873 static char * 874 origin_subst_one(char *real, const char *kw, const char *subst, 875 bool may_free) 876 { 877 char *p, *p1, *res, *resp; 878 int subst_len, kw_len, subst_count, old_len, new_len; 879 880 kw_len = strlen(kw); 881 882 /* 883 * First, count the number of the keyword occurrences, to 884 * preallocate the final string. 885 */ 886 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 887 p1 = strstr(p, kw); 888 if (p1 == NULL) 889 break; 890 } 891 892 /* 893 * If the keyword is not found, just return. 894 */ 895 if (subst_count == 0) 896 return (may_free ? real : xstrdup(real)); 897 898 /* 899 * There is indeed something to substitute. Calculate the 900 * length of the resulting string, and allocate it. 901 */ 902 subst_len = strlen(subst); 903 old_len = strlen(real); 904 new_len = old_len + (subst_len - kw_len) * subst_count; 905 res = xmalloc(new_len + 1); 906 907 /* 908 * Now, execute the substitution loop. 909 */ 910 for (p = real, resp = res, *resp = '\0';;) { 911 p1 = strstr(p, kw); 912 if (p1 != NULL) { 913 /* Copy the prefix before keyword. */ 914 memcpy(resp, p, p1 - p); 915 resp += p1 - p; 916 /* Keyword replacement. */ 917 memcpy(resp, subst, subst_len); 918 resp += subst_len; 919 *resp = '\0'; 920 p = p1 + kw_len; 921 } else 922 break; 923 } 924 925 /* Copy to the end of string and finish. */ 926 strcat(resp, p); 927 if (may_free) 928 free(real); 929 return (res); 930 } 931 932 static char * 933 origin_subst(char *real, const char *origin_path) 934 { 935 char *res1, *res2, *res3, *res4; 936 937 if (uts.sysname[0] == '\0') { 938 if (uname(&uts) != 0) { 939 _rtld_error("utsname failed: %d", errno); 940 return (NULL); 941 } 942 } 943 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 944 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 945 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 946 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 947 return (res4); 948 } 949 950 static void 951 die(void) 952 { 953 const char *msg = dlerror(); 954 955 if (msg == NULL) 956 msg = "Fatal error"; 957 rtld_fdputstr(STDERR_FILENO, msg); 958 rtld_fdputchar(STDERR_FILENO, '\n'); 959 _exit(1); 960 } 961 962 /* 963 * Process a shared object's DYNAMIC section, and save the important 964 * information in its Obj_Entry structure. 965 */ 966 static void 967 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 968 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 969 { 970 const Elf_Dyn *dynp; 971 Needed_Entry **needed_tail = &obj->needed; 972 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 973 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 974 const Elf_Hashelt *hashtab; 975 const Elf32_Word *hashval; 976 Elf32_Word bkt, nmaskwords; 977 int bloom_size32; 978 bool nmw_power2; 979 int plttype = DT_REL; 980 981 *dyn_rpath = NULL; 982 *dyn_soname = NULL; 983 *dyn_runpath = NULL; 984 985 obj->bind_now = false; 986 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 987 switch (dynp->d_tag) { 988 989 case DT_REL: 990 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 991 break; 992 993 case DT_RELSZ: 994 obj->relsize = dynp->d_un.d_val; 995 break; 996 997 case DT_RELENT: 998 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 999 break; 1000 1001 case DT_JMPREL: 1002 obj->pltrel = (const Elf_Rel *) 1003 (obj->relocbase + dynp->d_un.d_ptr); 1004 break; 1005 1006 case DT_PLTRELSZ: 1007 obj->pltrelsize = dynp->d_un.d_val; 1008 break; 1009 1010 case DT_RELA: 1011 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1012 break; 1013 1014 case DT_RELASZ: 1015 obj->relasize = dynp->d_un.d_val; 1016 break; 1017 1018 case DT_RELAENT: 1019 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1020 break; 1021 1022 case DT_PLTREL: 1023 plttype = dynp->d_un.d_val; 1024 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1025 break; 1026 1027 case DT_SYMTAB: 1028 obj->symtab = (const Elf_Sym *) 1029 (obj->relocbase + dynp->d_un.d_ptr); 1030 break; 1031 1032 case DT_SYMENT: 1033 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1034 break; 1035 1036 case DT_STRTAB: 1037 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1038 break; 1039 1040 case DT_STRSZ: 1041 obj->strsize = dynp->d_un.d_val; 1042 break; 1043 1044 case DT_VERNEED: 1045 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1046 dynp->d_un.d_val); 1047 break; 1048 1049 case DT_VERNEEDNUM: 1050 obj->verneednum = dynp->d_un.d_val; 1051 break; 1052 1053 case DT_VERDEF: 1054 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1055 dynp->d_un.d_val); 1056 break; 1057 1058 case DT_VERDEFNUM: 1059 obj->verdefnum = dynp->d_un.d_val; 1060 break; 1061 1062 case DT_VERSYM: 1063 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1064 dynp->d_un.d_val); 1065 break; 1066 1067 case DT_HASH: 1068 { 1069 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1070 dynp->d_un.d_ptr); 1071 obj->nbuckets = hashtab[0]; 1072 obj->nchains = hashtab[1]; 1073 obj->buckets = hashtab + 2; 1074 obj->chains = obj->buckets + obj->nbuckets; 1075 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1076 obj->buckets != NULL; 1077 } 1078 break; 1079 1080 case DT_GNU_HASH: 1081 { 1082 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1083 dynp->d_un.d_ptr); 1084 obj->nbuckets_gnu = hashtab[0]; 1085 obj->symndx_gnu = hashtab[1]; 1086 nmaskwords = hashtab[2]; 1087 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1088 /* Number of bitmask words is required to be power of 2 */ 1089 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 1090 obj->maskwords_bm_gnu = nmaskwords - 1; 1091 obj->shift2_gnu = hashtab[3]; 1092 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1093 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1094 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1095 obj->symndx_gnu; 1096 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 1097 obj->buckets_gnu != NULL; 1098 } 1099 break; 1100 1101 case DT_NEEDED: 1102 if (!obj->rtld) { 1103 Needed_Entry *nep = NEW(Needed_Entry); 1104 nep->name = dynp->d_un.d_val; 1105 nep->obj = NULL; 1106 nep->next = NULL; 1107 1108 *needed_tail = nep; 1109 needed_tail = &nep->next; 1110 } 1111 break; 1112 1113 case DT_FILTER: 1114 if (!obj->rtld) { 1115 Needed_Entry *nep = NEW(Needed_Entry); 1116 nep->name = dynp->d_un.d_val; 1117 nep->obj = NULL; 1118 nep->next = NULL; 1119 1120 *needed_filtees_tail = nep; 1121 needed_filtees_tail = &nep->next; 1122 } 1123 break; 1124 1125 case DT_AUXILIARY: 1126 if (!obj->rtld) { 1127 Needed_Entry *nep = NEW(Needed_Entry); 1128 nep->name = dynp->d_un.d_val; 1129 nep->obj = NULL; 1130 nep->next = NULL; 1131 1132 *needed_aux_filtees_tail = nep; 1133 needed_aux_filtees_tail = &nep->next; 1134 } 1135 break; 1136 1137 case DT_PLTGOT: 1138 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1139 break; 1140 1141 case DT_TEXTREL: 1142 obj->textrel = true; 1143 break; 1144 1145 case DT_SYMBOLIC: 1146 obj->symbolic = true; 1147 break; 1148 1149 case DT_RPATH: 1150 /* 1151 * We have to wait until later to process this, because we 1152 * might not have gotten the address of the string table yet. 1153 */ 1154 *dyn_rpath = dynp; 1155 break; 1156 1157 case DT_SONAME: 1158 *dyn_soname = dynp; 1159 break; 1160 1161 case DT_RUNPATH: 1162 *dyn_runpath = dynp; 1163 break; 1164 1165 case DT_INIT: 1166 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1167 break; 1168 1169 case DT_PREINIT_ARRAY: 1170 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1171 break; 1172 1173 case DT_PREINIT_ARRAYSZ: 1174 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1175 break; 1176 1177 case DT_INIT_ARRAY: 1178 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1179 break; 1180 1181 case DT_INIT_ARRAYSZ: 1182 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1183 break; 1184 1185 case DT_FINI: 1186 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1187 break; 1188 1189 case DT_FINI_ARRAY: 1190 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1191 break; 1192 1193 case DT_FINI_ARRAYSZ: 1194 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1195 break; 1196 1197 case DT_DEBUG: 1198 /* XXX - not implemented yet */ 1199 if (!early) 1200 dbg("Filling in DT_DEBUG entry"); 1201 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1202 break; 1203 1204 case DT_FLAGS: 1205 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1206 obj->z_origin = true; 1207 if (dynp->d_un.d_val & DF_SYMBOLIC) 1208 obj->symbolic = true; 1209 if (dynp->d_un.d_val & DF_TEXTREL) 1210 obj->textrel = true; 1211 if (dynp->d_un.d_val & DF_BIND_NOW) 1212 obj->bind_now = true; 1213 if (dynp->d_un.d_val & DF_STATIC_TLS) 1214 obj->static_tls = true; 1215 break; 1216 1217 case DT_FLAGS_1: 1218 if (dynp->d_un.d_val & DF_1_NOOPEN) 1219 obj->z_noopen = true; 1220 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1221 obj->z_origin = true; 1222 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1223 XXX ;*/ 1224 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1225 obj->bind_now = true; 1226 if (dynp->d_un.d_val & DF_1_NODELETE) 1227 obj->z_nodelete = true; 1228 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1229 obj->z_loadfltr = true; 1230 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1231 obj->z_interpose = true; 1232 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1233 obj->z_nodeflib = true; 1234 break; 1235 1236 default: 1237 if (!early) { 1238 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1239 (long)dynp->d_tag); 1240 } 1241 break; 1242 } 1243 } 1244 1245 obj->traced = false; 1246 1247 if (plttype == DT_RELA) { 1248 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1249 obj->pltrel = NULL; 1250 obj->pltrelasize = obj->pltrelsize; 1251 obj->pltrelsize = 0; 1252 } 1253 1254 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1255 if (obj->valid_hash_sysv) 1256 obj->dynsymcount = obj->nchains; 1257 else if (obj->valid_hash_gnu) { 1258 obj->dynsymcount = 0; 1259 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1260 if (obj->buckets_gnu[bkt] == 0) 1261 continue; 1262 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1263 do 1264 obj->dynsymcount++; 1265 while ((*hashval++ & 1u) == 0); 1266 } 1267 obj->dynsymcount += obj->symndx_gnu; 1268 } 1269 } 1270 1271 static void 1272 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1273 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1274 { 1275 1276 if (obj->z_origin && obj->origin_path == NULL) { 1277 obj->origin_path = xmalloc(PATH_MAX); 1278 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1279 die(); 1280 } 1281 1282 if (dyn_runpath != NULL) { 1283 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1284 if (obj->z_origin) 1285 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1286 } 1287 else if (dyn_rpath != NULL) { 1288 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1289 if (obj->z_origin) 1290 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1291 } 1292 1293 if (dyn_soname != NULL) 1294 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1295 } 1296 1297 static void 1298 digest_dynamic(Obj_Entry *obj, int early) 1299 { 1300 const Elf_Dyn *dyn_rpath; 1301 const Elf_Dyn *dyn_soname; 1302 const Elf_Dyn *dyn_runpath; 1303 1304 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1305 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1306 } 1307 1308 /* 1309 * Process a shared object's program header. This is used only for the 1310 * main program, when the kernel has already loaded the main program 1311 * into memory before calling the dynamic linker. It creates and 1312 * returns an Obj_Entry structure. 1313 */ 1314 static Obj_Entry * 1315 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1316 { 1317 Obj_Entry *obj; 1318 const Elf_Phdr *phlimit = phdr + phnum; 1319 const Elf_Phdr *ph; 1320 Elf_Addr note_start, note_end; 1321 int nsegs = 0; 1322 1323 obj = obj_new(); 1324 for (ph = phdr; ph < phlimit; ph++) { 1325 if (ph->p_type != PT_PHDR) 1326 continue; 1327 1328 obj->phdr = phdr; 1329 obj->phsize = ph->p_memsz; 1330 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1331 break; 1332 } 1333 1334 obj->stack_flags = PF_X | PF_R | PF_W; 1335 1336 for (ph = phdr; ph < phlimit; ph++) { 1337 switch (ph->p_type) { 1338 1339 case PT_INTERP: 1340 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1341 break; 1342 1343 case PT_LOAD: 1344 if (nsegs == 0) { /* First load segment */ 1345 obj->vaddrbase = trunc_page(ph->p_vaddr); 1346 obj->mapbase = obj->vaddrbase + obj->relocbase; 1347 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1348 obj->vaddrbase; 1349 } else { /* Last load segment */ 1350 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1351 obj->vaddrbase; 1352 } 1353 nsegs++; 1354 break; 1355 1356 case PT_DYNAMIC: 1357 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1358 break; 1359 1360 case PT_TLS: 1361 obj->tlsindex = 1; 1362 obj->tlssize = ph->p_memsz; 1363 obj->tlsalign = ph->p_align; 1364 obj->tlsinitsize = ph->p_filesz; 1365 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1366 break; 1367 1368 case PT_GNU_STACK: 1369 obj->stack_flags = ph->p_flags; 1370 break; 1371 1372 case PT_GNU_RELRO: 1373 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1374 obj->relro_size = round_page(ph->p_memsz); 1375 break; 1376 1377 case PT_NOTE: 1378 obj->note_present = true; 1379 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1380 note_end = note_start + ph->p_filesz; 1381 digest_notes(obj, note_start, note_end); 1382 break; 1383 } 1384 } 1385 if (nsegs < 1) { 1386 _rtld_error("%s: too few PT_LOAD segments", path); 1387 return NULL; 1388 } 1389 1390 obj->entry = entry; 1391 return obj; 1392 } 1393 1394 void 1395 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1396 { 1397 const Elf_Note *note; 1398 const char *note_name; 1399 uintptr_t p; 1400 1401 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1402 note = (const Elf_Note *)((const char *)(note + 1) + 1403 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1404 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1405 if (note->n_namesz != sizeof(NOTE_VENDOR) || 1406 note->n_descsz != sizeof(int32_t)) 1407 continue; 1408 if (note->n_type != ABI_NOTETYPE && 1409 note->n_type != CRT_NOINIT_NOTETYPE) 1410 continue; 1411 note_name = (const char *)(note + 1); 1412 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0) 1413 continue; 1414 switch (note->n_type) { 1415 case ABI_NOTETYPE: 1416 /* DragonFly osrel note */ 1417 p = (uintptr_t)(note + 1); 1418 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1419 obj->osrel = *(const int32_t *)(p); 1420 dbg("note osrel %d", obj->osrel); 1421 break; 1422 case CRT_NOINIT_NOTETYPE: 1423 /* DragonFly 'crt does not call init' note */ 1424 obj->crt_no_init = true; 1425 dbg("note crt_no_init"); 1426 break; 1427 } 1428 } 1429 } 1430 1431 static Obj_Entry * 1432 dlcheck(void *handle) 1433 { 1434 Obj_Entry *obj; 1435 1436 for (obj = obj_list; obj != NULL; obj = obj->next) 1437 if (obj == (Obj_Entry *) handle) 1438 break; 1439 1440 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1441 _rtld_error("Invalid shared object handle %p", handle); 1442 return NULL; 1443 } 1444 return obj; 1445 } 1446 1447 /* 1448 * If the given object is already in the donelist, return true. Otherwise 1449 * add the object to the list and return false. 1450 */ 1451 static bool 1452 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1453 { 1454 unsigned int i; 1455 1456 for (i = 0; i < dlp->num_used; i++) 1457 if (dlp->objs[i] == obj) 1458 return true; 1459 /* 1460 * Our donelist allocation should always be sufficient. But if 1461 * our threads locking isn't working properly, more shared objects 1462 * could have been loaded since we allocated the list. That should 1463 * never happen, but we'll handle it properly just in case it does. 1464 */ 1465 if (dlp->num_used < dlp->num_alloc) 1466 dlp->objs[dlp->num_used++] = obj; 1467 return false; 1468 } 1469 1470 /* 1471 * Hash function for symbol table lookup. Don't even think about changing 1472 * this. It is specified by the System V ABI. 1473 */ 1474 unsigned long 1475 elf_hash(const char *name) 1476 { 1477 const unsigned char *p = (const unsigned char *) name; 1478 unsigned long h = 0; 1479 unsigned long g; 1480 1481 while (*p != '\0') { 1482 h = (h << 4) + *p++; 1483 if ((g = h & 0xf0000000) != 0) 1484 h ^= g >> 24; 1485 h &= ~g; 1486 } 1487 return h; 1488 } 1489 1490 /* 1491 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1492 * unsigned in case it's implemented with a wider type. 1493 */ 1494 static uint_fast32_t 1495 gnu_hash(const char *s) 1496 { 1497 uint_fast32_t h; 1498 unsigned char c; 1499 1500 h = 5381; 1501 for (c = *s; c != '\0'; c = *++s) 1502 h = h * 33 + c; 1503 return (h & 0xffffffff); 1504 } 1505 1506 1507 /* 1508 * Find the library with the given name, and return its full pathname. 1509 * The returned string is dynamically allocated. Generates an error 1510 * message and returns NULL if the library cannot be found. 1511 * 1512 * If the second argument is non-NULL, then it refers to an already- 1513 * loaded shared object, whose library search path will be searched. 1514 * 1515 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1516 * descriptor (which is close-on-exec) will be passed out via the third 1517 * argument. 1518 * 1519 * The search order is: 1520 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1521 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1522 * LD_LIBRARY_PATH 1523 * DT_RUNPATH in the referencing file 1524 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1525 * from list) 1526 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1527 * 1528 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1529 */ 1530 static char * 1531 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1532 { 1533 char *pathname; 1534 char *name; 1535 bool nodeflib, objgiven; 1536 1537 objgiven = refobj != NULL; 1538 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1539 if (xname[0] != '/' && !trust) { 1540 _rtld_error("Absolute pathname required for shared object \"%s\"", 1541 xname); 1542 return NULL; 1543 } 1544 if (objgiven && refobj->z_origin) { 1545 return (origin_subst(__DECONST(char *, xname), 1546 refobj->origin_path)); 1547 } else { 1548 return (xstrdup(xname)); 1549 } 1550 } 1551 1552 if (libmap_disable || !objgiven || 1553 (name = lm_find(refobj->path, xname)) == NULL) 1554 name = (char *)xname; 1555 1556 dbg(" Searching for \"%s\"", name); 1557 1558 nodeflib = objgiven ? refobj->z_nodeflib : false; 1559 if ((objgiven && 1560 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1561 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1562 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1563 (pathname = search_library_path(name, ld_library_path)) != NULL || 1564 (objgiven && 1565 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1566 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1567 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1568 (objgiven && !nodeflib && 1569 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1570 return (pathname); 1571 1572 if (objgiven && refobj->path != NULL) { 1573 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1574 name, basename(refobj->path)); 1575 } else { 1576 _rtld_error("Shared object \"%s\" not found", name); 1577 } 1578 return NULL; 1579 } 1580 1581 /* 1582 * Given a symbol number in a referencing object, find the corresponding 1583 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1584 * no definition was found. Returns a pointer to the Obj_Entry of the 1585 * defining object via the reference parameter DEFOBJ_OUT. 1586 */ 1587 const Elf_Sym * 1588 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1589 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1590 RtldLockState *lockstate) 1591 { 1592 const Elf_Sym *ref; 1593 const Elf_Sym *def; 1594 const Obj_Entry *defobj; 1595 SymLook req; 1596 const char *name; 1597 int res; 1598 1599 /* 1600 * If we have already found this symbol, get the information from 1601 * the cache. 1602 */ 1603 if (symnum >= refobj->dynsymcount) 1604 return NULL; /* Bad object */ 1605 if (cache != NULL && cache[symnum].sym != NULL) { 1606 *defobj_out = cache[symnum].obj; 1607 return cache[symnum].sym; 1608 } 1609 1610 ref = refobj->symtab + symnum; 1611 name = refobj->strtab + ref->st_name; 1612 def = NULL; 1613 defobj = NULL; 1614 1615 /* 1616 * We don't have to do a full scale lookup if the symbol is local. 1617 * We know it will bind to the instance in this load module; to 1618 * which we already have a pointer (ie ref). By not doing a lookup, 1619 * we not only improve performance, but it also avoids unresolvable 1620 * symbols when local symbols are not in the hash table. 1621 * 1622 * This might occur for TLS module relocations, which simply use 1623 * symbol 0. 1624 */ 1625 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1626 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1627 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1628 symnum); 1629 } 1630 symlook_init(&req, name); 1631 req.flags = flags; 1632 req.ventry = fetch_ventry(refobj, symnum); 1633 req.lockstate = lockstate; 1634 res = symlook_default(&req, refobj); 1635 if (res == 0) { 1636 def = req.sym_out; 1637 defobj = req.defobj_out; 1638 } 1639 } else { 1640 def = ref; 1641 defobj = refobj; 1642 } 1643 1644 /* 1645 * If we found no definition and the reference is weak, treat the 1646 * symbol as having the value zero. 1647 */ 1648 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1649 def = &sym_zero; 1650 defobj = obj_main; 1651 } 1652 1653 if (def != NULL) { 1654 *defobj_out = defobj; 1655 /* Record the information in the cache to avoid subsequent lookups. */ 1656 if (cache != NULL) { 1657 cache[symnum].sym = def; 1658 cache[symnum].obj = defobj; 1659 } 1660 } else { 1661 if (refobj != &obj_rtld) 1662 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1663 } 1664 return def; 1665 } 1666 1667 /* 1668 * Return the search path from the ldconfig hints file, reading it if 1669 * necessary. If nostdlib is true, then the default search paths are 1670 * not added to result. 1671 * 1672 * Returns NULL if there are problems with the hints file, 1673 * or if the search path there is empty. 1674 */ 1675 static const char * 1676 gethints(bool nostdlib) 1677 { 1678 static char *hints, *filtered_path; 1679 struct elfhints_hdr hdr; 1680 struct fill_search_info_args sargs, hargs; 1681 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1682 struct dl_serpath *SLPpath, *hintpath; 1683 char *p; 1684 unsigned int SLPndx, hintndx, fndx, fcount; 1685 int fd; 1686 size_t flen; 1687 bool skip; 1688 1689 /* First call, read the hints file */ 1690 if (hints == NULL) { 1691 /* Keep from trying again in case the hints file is bad. */ 1692 hints = ""; 1693 1694 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1695 return (NULL); 1696 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1697 hdr.magic != ELFHINTS_MAGIC || 1698 hdr.version != 1) { 1699 close(fd); 1700 return (NULL); 1701 } 1702 p = xmalloc(hdr.dirlistlen + 1); 1703 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1704 read(fd, p, hdr.dirlistlen + 1) != 1705 (ssize_t)hdr.dirlistlen + 1) { 1706 free(p); 1707 close(fd); 1708 return (NULL); 1709 } 1710 hints = p; 1711 close(fd); 1712 } 1713 1714 /* 1715 * If caller agreed to receive list which includes the default 1716 * paths, we are done. Otherwise, if we still have not 1717 * calculated filtered result, do it now. 1718 */ 1719 if (!nostdlib) 1720 return (hints[0] != '\0' ? hints : NULL); 1721 if (filtered_path != NULL) 1722 goto filt_ret; 1723 1724 /* 1725 * Obtain the list of all configured search paths, and the 1726 * list of the default paths. 1727 * 1728 * First estimate the size of the results. 1729 */ 1730 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1731 smeta.dls_cnt = 0; 1732 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1733 hmeta.dls_cnt = 0; 1734 1735 sargs.request = RTLD_DI_SERINFOSIZE; 1736 sargs.serinfo = &smeta; 1737 hargs.request = RTLD_DI_SERINFOSIZE; 1738 hargs.serinfo = &hmeta; 1739 1740 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1741 path_enumerate(p, fill_search_info, &hargs); 1742 1743 SLPinfo = xmalloc(smeta.dls_size); 1744 hintinfo = xmalloc(hmeta.dls_size); 1745 1746 /* 1747 * Next fetch both sets of paths. 1748 */ 1749 sargs.request = RTLD_DI_SERINFO; 1750 sargs.serinfo = SLPinfo; 1751 sargs.serpath = &SLPinfo->dls_serpath[0]; 1752 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1753 1754 hargs.request = RTLD_DI_SERINFO; 1755 hargs.serinfo = hintinfo; 1756 hargs.serpath = &hintinfo->dls_serpath[0]; 1757 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1758 1759 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1760 path_enumerate(p, fill_search_info, &hargs); 1761 1762 /* 1763 * Now calculate the difference between two sets, by excluding 1764 * standard paths from the full set. 1765 */ 1766 fndx = 0; 1767 fcount = 0; 1768 filtered_path = xmalloc(hdr.dirlistlen + 1); 1769 hintpath = &hintinfo->dls_serpath[0]; 1770 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1771 skip = false; 1772 SLPpath = &SLPinfo->dls_serpath[0]; 1773 /* 1774 * Check each standard path against current. 1775 */ 1776 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1777 /* matched, skip the path */ 1778 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1779 skip = true; 1780 break; 1781 } 1782 } 1783 if (skip) 1784 continue; 1785 /* 1786 * Not matched against any standard path, add the path 1787 * to result. Separate consecutive paths with ':'. 1788 */ 1789 if (fcount > 0) { 1790 filtered_path[fndx] = ':'; 1791 fndx++; 1792 } 1793 fcount++; 1794 flen = strlen(hintpath->dls_name); 1795 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1796 fndx += flen; 1797 } 1798 filtered_path[fndx] = '\0'; 1799 1800 free(SLPinfo); 1801 free(hintinfo); 1802 1803 filt_ret: 1804 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1805 } 1806 1807 static void 1808 init_dag(Obj_Entry *root) 1809 { 1810 const Needed_Entry *needed; 1811 const Objlist_Entry *elm; 1812 DoneList donelist; 1813 1814 if (root->dag_inited) 1815 return; 1816 donelist_init(&donelist); 1817 1818 /* Root object belongs to own DAG. */ 1819 objlist_push_tail(&root->dldags, root); 1820 objlist_push_tail(&root->dagmembers, root); 1821 donelist_check(&donelist, root); 1822 1823 /* 1824 * Add dependencies of root object to DAG in breadth order 1825 * by exploiting the fact that each new object get added 1826 * to the tail of the dagmembers list. 1827 */ 1828 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1829 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1830 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1831 continue; 1832 objlist_push_tail(&needed->obj->dldags, root); 1833 objlist_push_tail(&root->dagmembers, needed->obj); 1834 } 1835 } 1836 root->dag_inited = true; 1837 } 1838 1839 static void 1840 process_nodelete(Obj_Entry *root) 1841 { 1842 const Objlist_Entry *elm; 1843 1844 /* 1845 * Walk over object DAG and process every dependent object that 1846 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1847 * which then should have its reference upped separately. 1848 */ 1849 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1850 if (elm->obj != NULL && elm->obj->z_nodelete && 1851 !elm->obj->ref_nodel) { 1852 dbg("obj %s nodelete", elm->obj->path); 1853 init_dag(elm->obj); 1854 ref_dag(elm->obj); 1855 elm->obj->ref_nodel = true; 1856 } 1857 } 1858 } 1859 1860 /* 1861 * Initialize the dynamic linker. The argument is the address at which 1862 * the dynamic linker has been mapped into memory. The primary task of 1863 * this function is to relocate the dynamic linker. 1864 */ 1865 static void 1866 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1867 { 1868 Obj_Entry objtmp; /* Temporary rtld object */ 1869 const Elf_Ehdr *ehdr; 1870 const Elf_Dyn *dyn_rpath; 1871 const Elf_Dyn *dyn_soname; 1872 const Elf_Dyn *dyn_runpath; 1873 1874 /* 1875 * Conjure up an Obj_Entry structure for the dynamic linker. 1876 * 1877 * The "path" member can't be initialized yet because string constants 1878 * cannot yet be accessed. Below we will set it correctly. 1879 */ 1880 memset(&objtmp, 0, sizeof(objtmp)); 1881 objtmp.path = NULL; 1882 objtmp.rtld = true; 1883 objtmp.mapbase = mapbase; 1884 #ifdef PIC 1885 objtmp.relocbase = mapbase; 1886 #endif 1887 if (RTLD_IS_DYNAMIC()) { 1888 objtmp.dynamic = rtld_dynamic(&objtmp); 1889 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1890 assert(objtmp.needed == NULL); 1891 assert(!objtmp.textrel); 1892 1893 /* 1894 * Temporarily put the dynamic linker entry into the object list, so 1895 * that symbols can be found. 1896 */ 1897 1898 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1899 } 1900 ehdr = (Elf_Ehdr *)mapbase; 1901 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1902 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1903 1904 /* Initialize the object list. */ 1905 obj_tail = &obj_list; 1906 1907 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1908 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1909 1910 #ifdef ENABLE_OSRELDATE 1911 if (aux_info[AT_OSRELDATE] != NULL) 1912 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1913 #endif 1914 1915 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1916 1917 /* Replace the path with a dynamically allocated copy. */ 1918 obj_rtld.path = xstrdup(PATH_RTLD); 1919 1920 r_debug.r_brk = r_debug_state; 1921 r_debug.r_state = RT_CONSISTENT; 1922 } 1923 1924 /* 1925 * Add the init functions from a needed object list (and its recursive 1926 * needed objects) to "list". This is not used directly; it is a helper 1927 * function for initlist_add_objects(). The write lock must be held 1928 * when this function is called. 1929 */ 1930 static void 1931 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1932 { 1933 /* Recursively process the successor needed objects. */ 1934 if (needed->next != NULL) 1935 initlist_add_neededs(needed->next, list); 1936 1937 /* Process the current needed object. */ 1938 if (needed->obj != NULL) 1939 initlist_add_objects(needed->obj, &needed->obj->next, list); 1940 } 1941 1942 /* 1943 * Scan all of the DAGs rooted in the range of objects from "obj" to 1944 * "tail" and add their init functions to "list". This recurses over 1945 * the DAGs and ensure the proper init ordering such that each object's 1946 * needed libraries are initialized before the object itself. At the 1947 * same time, this function adds the objects to the global finalization 1948 * list "list_fini" in the opposite order. The write lock must be 1949 * held when this function is called. 1950 */ 1951 static void 1952 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1953 { 1954 1955 if (obj->init_scanned || obj->init_done) 1956 return; 1957 obj->init_scanned = true; 1958 1959 /* Recursively process the successor objects. */ 1960 if (&obj->next != tail) 1961 initlist_add_objects(obj->next, tail, list); 1962 1963 /* Recursively process the needed objects. */ 1964 if (obj->needed != NULL) 1965 initlist_add_neededs(obj->needed, list); 1966 if (obj->needed_filtees != NULL) 1967 initlist_add_neededs(obj->needed_filtees, list); 1968 if (obj->needed_aux_filtees != NULL) 1969 initlist_add_neededs(obj->needed_aux_filtees, list); 1970 1971 /* Add the object to the init list. */ 1972 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1973 obj->init_array != (Elf_Addr)NULL) 1974 objlist_push_tail(list, obj); 1975 1976 /* Add the object to the global fini list in the reverse order. */ 1977 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1978 && !obj->on_fini_list) { 1979 objlist_push_head(&list_fini, obj); 1980 obj->on_fini_list = true; 1981 } 1982 } 1983 1984 #ifndef FPTR_TARGET 1985 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1986 #endif 1987 1988 static void 1989 free_needed_filtees(Needed_Entry *n) 1990 { 1991 Needed_Entry *needed, *needed1; 1992 1993 for (needed = n; needed != NULL; needed = needed->next) { 1994 if (needed->obj != NULL) { 1995 dlclose(needed->obj); 1996 needed->obj = NULL; 1997 } 1998 } 1999 for (needed = n; needed != NULL; needed = needed1) { 2000 needed1 = needed->next; 2001 free(needed); 2002 } 2003 } 2004 2005 static void 2006 unload_filtees(Obj_Entry *obj) 2007 { 2008 2009 free_needed_filtees(obj->needed_filtees); 2010 obj->needed_filtees = NULL; 2011 free_needed_filtees(obj->needed_aux_filtees); 2012 obj->needed_aux_filtees = NULL; 2013 obj->filtees_loaded = false; 2014 } 2015 2016 static void 2017 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2018 RtldLockState *lockstate) 2019 { 2020 2021 for (; needed != NULL; needed = needed->next) { 2022 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2023 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2024 RTLD_LOCAL, lockstate); 2025 } 2026 } 2027 2028 static void 2029 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2030 { 2031 2032 lock_restart_for_upgrade(lockstate); 2033 if (!obj->filtees_loaded) { 2034 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2035 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2036 obj->filtees_loaded = true; 2037 } 2038 } 2039 2040 static int 2041 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2042 { 2043 Obj_Entry *obj1; 2044 2045 for (; needed != NULL; needed = needed->next) { 2046 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2047 flags & ~RTLD_LO_NOLOAD); 2048 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2049 return (-1); 2050 } 2051 return (0); 2052 } 2053 2054 /* 2055 * Given a shared object, traverse its list of needed objects, and load 2056 * each of them. Returns 0 on success. Generates an error message and 2057 * returns -1 on failure. 2058 */ 2059 static int 2060 load_needed_objects(Obj_Entry *first, int flags) 2061 { 2062 Obj_Entry *obj; 2063 2064 for (obj = first; obj != NULL; obj = obj->next) { 2065 if (process_needed(obj, obj->needed, flags) == -1) 2066 return (-1); 2067 } 2068 return (0); 2069 } 2070 2071 static int 2072 load_preload_objects(void) 2073 { 2074 char *p = ld_preload; 2075 Obj_Entry *obj; 2076 static const char delim[] = " \t:;"; 2077 2078 if (p == NULL) 2079 return 0; 2080 2081 p += strspn(p, delim); 2082 while (*p != '\0') { 2083 size_t len = strcspn(p, delim); 2084 char savech; 2085 SymLook req; 2086 int res; 2087 2088 savech = p[len]; 2089 p[len] = '\0'; 2090 obj = load_object(p, -1, NULL, 0); 2091 if (obj == NULL) 2092 return -1; /* XXX - cleanup */ 2093 obj->z_interpose = true; 2094 p[len] = savech; 2095 p += len; 2096 p += strspn(p, delim); 2097 2098 /* Check for the magic tracing function */ 2099 symlook_init(&req, RTLD_FUNCTRACE); 2100 res = symlook_obj(&req, obj); 2101 if (res == 0) { 2102 rtld_functrace = (void *)(req.defobj_out->relocbase + 2103 req.sym_out->st_value); 2104 rtld_functrace_obj = req.defobj_out; 2105 } 2106 } 2107 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2108 return 0; 2109 } 2110 2111 static const char * 2112 printable_path(const char *path) 2113 { 2114 2115 return (path == NULL ? "<unknown>" : path); 2116 } 2117 2118 /* 2119 * Load a shared object into memory, if it is not already loaded. The 2120 * object may be specified by name or by user-supplied file descriptor 2121 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2122 * duplicate is. 2123 * 2124 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2125 * on failure. 2126 */ 2127 static Obj_Entry * 2128 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2129 { 2130 Obj_Entry *obj; 2131 int fd; 2132 struct stat sb; 2133 char *path; 2134 2135 fd = -1; 2136 if (name != NULL) { 2137 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2138 if (object_match_name(obj, name)) 2139 return (obj); 2140 } 2141 2142 path = find_library(name, refobj, &fd); 2143 if (path == NULL) 2144 return (NULL); 2145 } else 2146 path = NULL; 2147 2148 if (fd >= 0) { 2149 /* 2150 * search_library_pathfds() opens a fresh file descriptor for the 2151 * library, so there is no need to dup(). 2152 */ 2153 } else if (fd_u == -1) { 2154 /* 2155 * If we didn't find a match by pathname, or the name is not 2156 * supplied, open the file and check again by device and inode. 2157 * This avoids false mismatches caused by multiple links or ".." 2158 * in pathnames. 2159 * 2160 * To avoid a race, we open the file and use fstat() rather than 2161 * using stat(). 2162 */ 2163 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2164 _rtld_error("Cannot open \"%s\"", path); 2165 free(path); 2166 return (NULL); 2167 } 2168 } else { 2169 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2170 if (fd == -1) { 2171 _rtld_error("Cannot dup fd"); 2172 free(path); 2173 return (NULL); 2174 } 2175 } 2176 if (fstat(fd, &sb) == -1) { 2177 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2178 close(fd); 2179 free(path); 2180 return NULL; 2181 } 2182 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2183 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2184 break; 2185 if (obj != NULL && name != NULL) { 2186 object_add_name(obj, name); 2187 free(path); 2188 close(fd); 2189 return obj; 2190 } 2191 if (flags & RTLD_LO_NOLOAD) { 2192 free(path); 2193 close(fd); 2194 return (NULL); 2195 } 2196 2197 /* First use of this object, so we must map it in */ 2198 obj = do_load_object(fd, name, path, &sb, flags); 2199 if (obj == NULL) 2200 free(path); 2201 close(fd); 2202 2203 return obj; 2204 } 2205 2206 static Obj_Entry * 2207 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2208 int flags) 2209 { 2210 Obj_Entry *obj; 2211 struct statfs fs; 2212 2213 /* 2214 * but first, make sure that environment variables haven't been 2215 * used to circumvent the noexec flag on a filesystem. 2216 */ 2217 if (dangerous_ld_env) { 2218 if (fstatfs(fd, &fs) != 0) { 2219 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2220 return NULL; 2221 } 2222 if (fs.f_flags & MNT_NOEXEC) { 2223 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2224 return NULL; 2225 } 2226 } 2227 dbg("loading \"%s\"", printable_path(path)); 2228 obj = map_object(fd, printable_path(path), sbp); 2229 if (obj == NULL) 2230 return NULL; 2231 2232 /* 2233 * If DT_SONAME is present in the object, digest_dynamic2 already 2234 * added it to the object names. 2235 */ 2236 if (name != NULL) 2237 object_add_name(obj, name); 2238 obj->path = path; 2239 digest_dynamic(obj, 0); 2240 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2241 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2242 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2243 RTLD_LO_DLOPEN) { 2244 dbg("refusing to load non-loadable \"%s\"", obj->path); 2245 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2246 munmap(obj->mapbase, obj->mapsize); 2247 obj_free(obj); 2248 return (NULL); 2249 } 2250 2251 *obj_tail = obj; 2252 obj_tail = &obj->next; 2253 obj_count++; 2254 obj_loads++; 2255 linkmap_add(obj); /* for GDB & dlinfo() */ 2256 #if 0 2257 max_stack_flags |= obj->stack_flags; 2258 #endif 2259 2260 dbg(" %p .. %p: %s", obj->mapbase, 2261 obj->mapbase + obj->mapsize - 1, obj->path); 2262 if (obj->textrel) 2263 dbg(" WARNING: %s has impure text", obj->path); 2264 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2265 obj->path); 2266 2267 return obj; 2268 } 2269 2270 static Obj_Entry * 2271 obj_from_addr(const void *addr) 2272 { 2273 Obj_Entry *obj; 2274 2275 for (obj = obj_list; obj != NULL; obj = obj->next) { 2276 if (addr < (void *) obj->mapbase) 2277 continue; 2278 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2279 return obj; 2280 } 2281 return NULL; 2282 } 2283 2284 /* 2285 * If the main program is defined with a .preinit_array section, call 2286 * each function in order. This must occur before the initialization 2287 * of any shared object or the main program. 2288 */ 2289 static void 2290 preinit_main(void) 2291 { 2292 Elf_Addr *preinit_addr; 2293 int index; 2294 2295 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2296 if (preinit_addr == NULL) 2297 return; 2298 2299 for (index = 0; index < obj_main->preinit_array_num; index++) { 2300 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2301 dbg("calling preinit function for %s at %p", obj_main->path, 2302 (void *)preinit_addr[index]); 2303 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2304 0, 0, obj_main->path); 2305 call_init_pointer(obj_main, preinit_addr[index]); 2306 } 2307 } 2308 } 2309 2310 /* 2311 * Call the finalization functions for each of the objects in "list" 2312 * belonging to the DAG of "root" and referenced once. If NULL "root" 2313 * is specified, every finalization function will be called regardless 2314 * of the reference count and the list elements won't be freed. All of 2315 * the objects are expected to have non-NULL fini functions. 2316 */ 2317 static void 2318 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2319 { 2320 Objlist_Entry *elm; 2321 char *saved_msg; 2322 Elf_Addr *fini_addr; 2323 int index; 2324 2325 assert(root == NULL || root->refcount == 1); 2326 2327 /* 2328 * Preserve the current error message since a fini function might 2329 * call into the dynamic linker and overwrite it. 2330 */ 2331 saved_msg = errmsg_save(); 2332 do { 2333 STAILQ_FOREACH(elm, list, link) { 2334 if (root != NULL && (elm->obj->refcount != 1 || 2335 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2336 continue; 2337 2338 /* Remove object from fini list to prevent recursive invocation. */ 2339 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2340 /* 2341 * XXX: If a dlopen() call references an object while the 2342 * fini function is in progress, we might end up trying to 2343 * unload the referenced object in dlclose() or the object 2344 * won't be unloaded although its fini function has been 2345 * called. 2346 */ 2347 lock_release(rtld_bind_lock, lockstate); 2348 2349 /* 2350 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2351 * When this happens, DT_FINI_ARRAY is processed first. 2352 * It is also processed backwards. It is possible to encounter 2353 * DT_FINI_ARRAY elements with values of 0 or 1, but they need 2354 * to be ignored. 2355 */ 2356 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2357 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2358 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) { 2359 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2360 dbg("calling fini array function for %s at %p", 2361 elm->obj->path, (void *)fini_addr[index]); 2362 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2363 (void *)fini_addr[index], 0, 0, elm->obj->path); 2364 call_initfini_pointer(elm->obj, fini_addr[index]); 2365 } 2366 } 2367 } 2368 if (elm->obj->fini != (Elf_Addr)NULL) { 2369 dbg("calling fini function for %s at %p", elm->obj->path, 2370 (void *)elm->obj->fini); 2371 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2372 0, 0, elm->obj->path); 2373 call_initfini_pointer(elm->obj, elm->obj->fini); 2374 } 2375 wlock_acquire(rtld_bind_lock, lockstate); 2376 /* No need to free anything if process is going down. */ 2377 if (root != NULL) 2378 free(elm); 2379 /* 2380 * We must restart the list traversal after every fini call 2381 * because a dlclose() call from the fini function or from 2382 * another thread might have modified the reference counts. 2383 */ 2384 break; 2385 } 2386 } while (elm != NULL); 2387 errmsg_restore(saved_msg); 2388 } 2389 2390 /* 2391 * Call the initialization functions for each of the objects in 2392 * "list". All of the objects are expected to have non-NULL init 2393 * functions. 2394 */ 2395 static void 2396 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2397 { 2398 Objlist_Entry *elm; 2399 Obj_Entry *obj; 2400 char *saved_msg; 2401 Elf_Addr *init_addr; 2402 int index; 2403 2404 /* 2405 * Clean init_scanned flag so that objects can be rechecked and 2406 * possibly initialized earlier if any of vectors called below 2407 * cause the change by using dlopen. 2408 */ 2409 for (obj = obj_list; obj != NULL; obj = obj->next) 2410 obj->init_scanned = false; 2411 2412 /* 2413 * Preserve the current error message since an init function might 2414 * call into the dynamic linker and overwrite it. 2415 */ 2416 saved_msg = errmsg_save(); 2417 STAILQ_FOREACH(elm, list, link) { 2418 if (elm->obj->init_done) /* Initialized early. */ 2419 continue; 2420 2421 /* 2422 * Race: other thread might try to use this object before current 2423 * one completes the initilization. Not much can be done here 2424 * without better locking. 2425 */ 2426 elm->obj->init_done = true; 2427 lock_release(rtld_bind_lock, lockstate); 2428 2429 /* 2430 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2431 * When this happens, DT_INIT is processed first. 2432 * It is possible to encounter DT_INIT_ARRAY elements with values 2433 * of 0 or 1, but they need to be ignored. 2434 */ 2435 if (elm->obj->init != (Elf_Addr)NULL) { 2436 dbg("calling init function for %s at %p", elm->obj->path, 2437 (void *)elm->obj->init); 2438 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2439 0, 0, elm->obj->path); 2440 call_initfini_pointer(elm->obj, elm->obj->init); 2441 } 2442 init_addr = (Elf_Addr *)elm->obj->init_array; 2443 if (init_addr != NULL) { 2444 for (index = 0; index < elm->obj->init_array_num; index++) { 2445 if (init_addr[index] != 0 && init_addr[index] != 1) { 2446 dbg("calling init array function for %s at %p", elm->obj->path, 2447 (void *)init_addr[index]); 2448 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2449 (void *)init_addr[index], 0, 0, elm->obj->path); 2450 call_init_pointer(elm->obj, init_addr[index]); 2451 } 2452 } 2453 } 2454 wlock_acquire(rtld_bind_lock, lockstate); 2455 } 2456 errmsg_restore(saved_msg); 2457 } 2458 2459 static void 2460 objlist_clear(Objlist *list) 2461 { 2462 Objlist_Entry *elm; 2463 2464 while (!STAILQ_EMPTY(list)) { 2465 elm = STAILQ_FIRST(list); 2466 STAILQ_REMOVE_HEAD(list, link); 2467 free(elm); 2468 } 2469 } 2470 2471 static Objlist_Entry * 2472 objlist_find(Objlist *list, const Obj_Entry *obj) 2473 { 2474 Objlist_Entry *elm; 2475 2476 STAILQ_FOREACH(elm, list, link) 2477 if (elm->obj == obj) 2478 return elm; 2479 return NULL; 2480 } 2481 2482 static void 2483 objlist_init(Objlist *list) 2484 { 2485 STAILQ_INIT(list); 2486 } 2487 2488 static void 2489 objlist_push_head(Objlist *list, Obj_Entry *obj) 2490 { 2491 Objlist_Entry *elm; 2492 2493 elm = NEW(Objlist_Entry); 2494 elm->obj = obj; 2495 STAILQ_INSERT_HEAD(list, elm, link); 2496 } 2497 2498 static void 2499 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2500 { 2501 Objlist_Entry *elm; 2502 2503 elm = NEW(Objlist_Entry); 2504 elm->obj = obj; 2505 STAILQ_INSERT_TAIL(list, elm, link); 2506 } 2507 2508 static void 2509 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2510 { 2511 Objlist_Entry *elm, *listelm; 2512 2513 STAILQ_FOREACH(listelm, list, link) { 2514 if (listelm->obj == listobj) 2515 break; 2516 } 2517 elm = NEW(Objlist_Entry); 2518 elm->obj = obj; 2519 if (listelm != NULL) 2520 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2521 else 2522 STAILQ_INSERT_TAIL(list, elm, link); 2523 } 2524 2525 static void 2526 objlist_remove(Objlist *list, Obj_Entry *obj) 2527 { 2528 Objlist_Entry *elm; 2529 2530 if ((elm = objlist_find(list, obj)) != NULL) { 2531 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2532 free(elm); 2533 } 2534 } 2535 2536 /* 2537 * Relocate dag rooted in the specified object. 2538 * Returns 0 on success, or -1 on failure. 2539 */ 2540 2541 static int 2542 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2543 int flags, RtldLockState *lockstate) 2544 { 2545 Objlist_Entry *elm; 2546 int error; 2547 2548 error = 0; 2549 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2550 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2551 lockstate); 2552 if (error == -1) 2553 break; 2554 } 2555 return (error); 2556 } 2557 2558 /* 2559 * Prepare for, or clean after, relocating an object marked with 2560 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2561 * segments are remapped read-write. After relocations are done, the 2562 * segment's permissions are returned back to the modes specified in 2563 * the phdrs. If any relocation happened, or always for wired 2564 * program, COW is triggered. 2565 */ 2566 static int 2567 reloc_textrel_prot(Obj_Entry *obj, bool before) 2568 { 2569 const Elf_Phdr *ph; 2570 void *base; 2571 size_t l, sz; 2572 int prot; 2573 2574 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2575 l--, ph++) { 2576 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2577 continue; 2578 base = obj->relocbase + trunc_page(ph->p_vaddr); 2579 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2580 trunc_page(ph->p_vaddr); 2581 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2582 /* 2583 * Make sure modified text segments are included in the 2584 * core dump since we modified it. This unfortunately causes the 2585 * entire text segment to core-out but we don't have much of a 2586 * choice. We could try to only reenable core dumps on pages 2587 * in which relocations occured but that is likely most of the text 2588 * pages anyway, and even that would not work because the rest of 2589 * the text pages would wind up as a read-only OBJT_DEFAULT object 2590 * (created due to our modifications) backed by the original OBJT_VNODE 2591 * object, and the ELF coredump code is currently only able to dump 2592 * vnode records for pure vnode-backed mappings, not vnode backings 2593 * to memory objects. 2594 */ 2595 if (before == false) 2596 madvise(base, sz, MADV_CORE); 2597 if (mprotect(base, sz, prot) == -1) { 2598 _rtld_error("%s: Cannot write-%sable text segment: %s", 2599 obj->path, before ? "en" : "dis", 2600 rtld_strerror(errno)); 2601 return (-1); 2602 } 2603 } 2604 return (0); 2605 } 2606 2607 /* 2608 * Relocate single object. 2609 * Returns 0 on success, or -1 on failure. 2610 */ 2611 static int 2612 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2613 int flags, RtldLockState *lockstate) 2614 { 2615 2616 if (obj->relocated) 2617 return (0); 2618 obj->relocated = true; 2619 if (obj != rtldobj) 2620 dbg("relocating \"%s\"", obj->path); 2621 2622 if (obj->symtab == NULL || obj->strtab == NULL || 2623 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2624 _rtld_error("%s: Shared object has no run-time symbol table", 2625 obj->path); 2626 return (-1); 2627 } 2628 2629 /* There are relocations to the write-protected text segment. */ 2630 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2631 return (-1); 2632 2633 /* Process the non-PLT non-IFUNC relocations. */ 2634 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2635 return (-1); 2636 2637 /* Re-protected the text segment. */ 2638 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2639 return (-1); 2640 2641 /* Set the special PLT or GOT entries. */ 2642 init_pltgot(obj); 2643 2644 /* Process the PLT relocations. */ 2645 if (reloc_plt(obj) == -1) 2646 return (-1); 2647 /* Relocate the jump slots if we are doing immediate binding. */ 2648 if (obj->bind_now || bind_now) 2649 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2650 return (-1); 2651 2652 /* 2653 * Process the non-PLT IFUNC relocations. The relocations are 2654 * processed in two phases, because IFUNC resolvers may 2655 * reference other symbols, which must be readily processed 2656 * before resolvers are called. 2657 */ 2658 if (obj->non_plt_gnu_ifunc && 2659 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2660 return (-1); 2661 2662 /* 2663 * Set up the magic number and version in the Obj_Entry. These 2664 * were checked in the crt1.o from the original ElfKit, so we 2665 * set them for backward compatibility. 2666 */ 2667 obj->magic = RTLD_MAGIC; 2668 obj->version = RTLD_VERSION; 2669 2670 /* 2671 * Set relocated data to read-only status if protection specified 2672 */ 2673 2674 if (obj->relro_size) { 2675 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2676 _rtld_error("%s: Cannot enforce relro relocation: %s", 2677 obj->path, rtld_strerror(errno)); 2678 return (-1); 2679 } 2680 obj->relro_protected = true; 2681 } 2682 return (0); 2683 } 2684 2685 /* 2686 * Relocate newly-loaded shared objects. The argument is a pointer to 2687 * the Obj_Entry for the first such object. All objects from the first 2688 * to the end of the list of objects are relocated. Returns 0 on success, 2689 * or -1 on failure. 2690 */ 2691 static int 2692 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2693 int flags, RtldLockState *lockstate) 2694 { 2695 Obj_Entry *obj; 2696 int error; 2697 2698 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2699 error = relocate_object(obj, bind_now, rtldobj, flags, 2700 lockstate); 2701 if (error == -1) 2702 break; 2703 } 2704 return (error); 2705 } 2706 2707 /* 2708 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2709 * referencing STT_GNU_IFUNC symbols is postponed till the other 2710 * relocations are done. The indirect functions specified as 2711 * ifunc are allowed to call other symbols, so we need to have 2712 * objects relocated before asking for resolution from indirects. 2713 * 2714 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2715 * instead of the usual lazy handling of PLT slots. It is 2716 * consistent with how GNU does it. 2717 */ 2718 static int 2719 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2720 RtldLockState *lockstate) 2721 { 2722 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2723 return (-1); 2724 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2725 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2726 return (-1); 2727 return (0); 2728 } 2729 2730 static int 2731 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2732 RtldLockState *lockstate) 2733 { 2734 Obj_Entry *obj; 2735 2736 for (obj = first; obj != NULL; obj = obj->next) { 2737 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2738 return (-1); 2739 } 2740 return (0); 2741 } 2742 2743 static int 2744 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2745 RtldLockState *lockstate) 2746 { 2747 Objlist_Entry *elm; 2748 2749 STAILQ_FOREACH(elm, list, link) { 2750 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2751 lockstate) == -1) 2752 return (-1); 2753 } 2754 return (0); 2755 } 2756 2757 /* 2758 * Cleanup procedure. It will be called (by the atexit mechanism) just 2759 * before the process exits. 2760 */ 2761 static void 2762 rtld_exit(void) 2763 { 2764 RtldLockState lockstate; 2765 2766 wlock_acquire(rtld_bind_lock, &lockstate); 2767 dbg("rtld_exit()"); 2768 objlist_call_fini(&list_fini, NULL, &lockstate); 2769 /* No need to remove the items from the list, since we are exiting. */ 2770 if (!libmap_disable) 2771 lm_fini(); 2772 lock_release(rtld_bind_lock, &lockstate); 2773 } 2774 2775 /* 2776 * Iterate over a search path, translate each element, and invoke the 2777 * callback on the result. 2778 */ 2779 static void * 2780 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2781 { 2782 const char *trans; 2783 if (path == NULL) 2784 return (NULL); 2785 2786 path += strspn(path, ":;"); 2787 while (*path != '\0') { 2788 size_t len; 2789 char *res; 2790 2791 len = strcspn(path, ":;"); 2792 trans = lm_findn(NULL, path, len); 2793 if (trans) 2794 res = callback(trans, strlen(trans), arg); 2795 else 2796 res = callback(path, len, arg); 2797 2798 if (res != NULL) 2799 return (res); 2800 2801 path += len; 2802 path += strspn(path, ":;"); 2803 } 2804 2805 return (NULL); 2806 } 2807 2808 struct try_library_args { 2809 const char *name; 2810 size_t namelen; 2811 char *buffer; 2812 size_t buflen; 2813 }; 2814 2815 static void * 2816 try_library_path(const char *dir, size_t dirlen, void *param) 2817 { 2818 struct try_library_args *arg; 2819 2820 arg = param; 2821 if (*dir == '/' || trust) { 2822 char *pathname; 2823 2824 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2825 return (NULL); 2826 2827 pathname = arg->buffer; 2828 strncpy(pathname, dir, dirlen); 2829 pathname[dirlen] = '/'; 2830 strcpy(pathname + dirlen + 1, arg->name); 2831 2832 dbg(" Trying \"%s\"", pathname); 2833 if (access(pathname, F_OK) == 0) { /* We found it */ 2834 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2835 strcpy(pathname, arg->buffer); 2836 return (pathname); 2837 } 2838 } 2839 return (NULL); 2840 } 2841 2842 static char * 2843 search_library_path(const char *name, const char *path) 2844 { 2845 char *p; 2846 struct try_library_args arg; 2847 2848 if (path == NULL) 2849 return NULL; 2850 2851 arg.name = name; 2852 arg.namelen = strlen(name); 2853 arg.buffer = xmalloc(PATH_MAX); 2854 arg.buflen = PATH_MAX; 2855 2856 p = path_enumerate(path, try_library_path, &arg); 2857 2858 free(arg.buffer); 2859 2860 return (p); 2861 } 2862 2863 2864 /* 2865 * Finds the library with the given name using the directory descriptors 2866 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2867 * 2868 * Returns a freshly-opened close-on-exec file descriptor for the library, 2869 * or -1 if the library cannot be found. 2870 */ 2871 static char * 2872 search_library_pathfds(const char *name, const char *path, int *fdp) 2873 { 2874 char *envcopy, *fdstr, *found, *last_token; 2875 size_t len; 2876 int dirfd, fd; 2877 2878 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2879 2880 /* Don't load from user-specified libdirs into setuid binaries. */ 2881 if (!trust) 2882 return (NULL); 2883 2884 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2885 if (path == NULL) 2886 return (NULL); 2887 2888 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2889 if (name[0] == '/') { 2890 dbg("Absolute path (%s) passed to %s", name, __func__); 2891 return (NULL); 2892 } 2893 2894 /* 2895 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2896 * copy of the path, as strtok_r rewrites separator tokens 2897 * with '\0'. 2898 */ 2899 found = NULL; 2900 envcopy = xstrdup(path); 2901 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2902 fdstr = strtok_r(NULL, ":", &last_token)) { 2903 dirfd = parse_libdir(fdstr); 2904 if (dirfd < 0) 2905 break; 2906 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2907 if (fd >= 0) { 2908 *fdp = fd; 2909 len = strlen(fdstr) + strlen(name) + 3; 2910 found = xmalloc(len); 2911 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2912 _rtld_error("error generating '%d/%s'", 2913 dirfd, name); 2914 die(); 2915 } 2916 dbg("open('%s') => %d", found, fd); 2917 break; 2918 } 2919 } 2920 free(envcopy); 2921 2922 return (found); 2923 } 2924 2925 2926 int 2927 dlclose(void *handle) 2928 { 2929 Obj_Entry *root; 2930 RtldLockState lockstate; 2931 2932 wlock_acquire(rtld_bind_lock, &lockstate); 2933 root = dlcheck(handle); 2934 if (root == NULL) { 2935 lock_release(rtld_bind_lock, &lockstate); 2936 return -1; 2937 } 2938 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2939 root->path); 2940 2941 /* Unreference the object and its dependencies. */ 2942 root->dl_refcount--; 2943 2944 if (root->refcount == 1) { 2945 /* 2946 * The object will be no longer referenced, so we must unload it. 2947 * First, call the fini functions. 2948 */ 2949 objlist_call_fini(&list_fini, root, &lockstate); 2950 2951 unref_dag(root); 2952 2953 /* Finish cleaning up the newly-unreferenced objects. */ 2954 GDB_STATE(RT_DELETE,&root->linkmap); 2955 unload_object(root); 2956 GDB_STATE(RT_CONSISTENT,NULL); 2957 } else 2958 unref_dag(root); 2959 2960 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2961 lock_release(rtld_bind_lock, &lockstate); 2962 return 0; 2963 } 2964 2965 char * 2966 dlerror(void) 2967 { 2968 char *msg = error_message; 2969 error_message = NULL; 2970 return msg; 2971 } 2972 2973 void * 2974 dlopen(const char *name, int mode) 2975 { 2976 2977 return (rtld_dlopen(name, -1, mode)); 2978 } 2979 2980 void * 2981 fdlopen(int fd, int mode) 2982 { 2983 2984 return (rtld_dlopen(NULL, fd, mode)); 2985 } 2986 2987 static void * 2988 rtld_dlopen(const char *name, int fd, int mode) 2989 { 2990 RtldLockState lockstate; 2991 int lo_flags; 2992 2993 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2994 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2995 if (ld_tracing != NULL) { 2996 rlock_acquire(rtld_bind_lock, &lockstate); 2997 if (sigsetjmp(lockstate.env, 0) != 0) 2998 lock_upgrade(rtld_bind_lock, &lockstate); 2999 environ = (char **)*get_program_var_addr("environ", &lockstate); 3000 lock_release(rtld_bind_lock, &lockstate); 3001 } 3002 lo_flags = RTLD_LO_DLOPEN; 3003 if (mode & RTLD_NODELETE) 3004 lo_flags |= RTLD_LO_NODELETE; 3005 if (mode & RTLD_NOLOAD) 3006 lo_flags |= RTLD_LO_NOLOAD; 3007 if (ld_tracing != NULL) 3008 lo_flags |= RTLD_LO_TRACE; 3009 3010 return (dlopen_object(name, fd, obj_main, lo_flags, 3011 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3012 } 3013 3014 static void 3015 dlopen_cleanup(Obj_Entry *obj) 3016 { 3017 3018 obj->dl_refcount--; 3019 unref_dag(obj); 3020 if (obj->refcount == 0) 3021 unload_object(obj); 3022 } 3023 3024 static Obj_Entry * 3025 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3026 int mode, RtldLockState *lockstate) 3027 { 3028 Obj_Entry **old_obj_tail; 3029 Obj_Entry *obj; 3030 Objlist initlist; 3031 RtldLockState mlockstate; 3032 int result; 3033 3034 objlist_init(&initlist); 3035 3036 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3037 wlock_acquire(rtld_bind_lock, &mlockstate); 3038 lockstate = &mlockstate; 3039 } 3040 GDB_STATE(RT_ADD,NULL); 3041 3042 old_obj_tail = obj_tail; 3043 obj = NULL; 3044 if (name == NULL && fd == -1) { 3045 obj = obj_main; 3046 obj->refcount++; 3047 } else { 3048 obj = load_object(name, fd, refobj, lo_flags); 3049 } 3050 3051 if (obj) { 3052 obj->dl_refcount++; 3053 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3054 objlist_push_tail(&list_global, obj); 3055 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3056 assert(*old_obj_tail == obj); 3057 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls && 3058 !allocate_tls_offset(obj)) { 3059 _rtld_error("%s: No space available " 3060 "for static TLS", 3061 obj->path); 3062 result = -1; 3063 } else { 3064 result = 0; 3065 } 3066 if (result == 0) { 3067 result = load_needed_objects( 3068 obj, 3069 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3070 } 3071 init_dag(obj); 3072 ref_dag(obj); 3073 if (result != -1) 3074 result = rtld_verify_versions(&obj->dagmembers); 3075 if (result != -1 && ld_tracing) 3076 goto trace; 3077 if (result == -1 || relocate_object_dag(obj, 3078 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3079 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3080 lockstate) == -1) { 3081 dlopen_cleanup(obj); 3082 obj = NULL; 3083 } else if (lo_flags & RTLD_LO_EARLY) { 3084 /* 3085 * Do not call the init functions for early loaded 3086 * filtees. The image is still not initialized enough 3087 * for them to work. 3088 * 3089 * Our object is found by the global object list and 3090 * will be ordered among all init calls done right 3091 * before transferring control to main. 3092 */ 3093 } else { 3094 /* Make list of init functions to call. */ 3095 initlist_add_objects(obj, &obj->next, &initlist); 3096 } 3097 /* 3098 * Process all no_delete objects here, given them own 3099 * DAGs to prevent their dependencies from being unloaded. 3100 * This has to be done after we have loaded all of the 3101 * dependencies, so that we do not miss any. 3102 */ 3103 if (obj != NULL) 3104 process_nodelete(obj); 3105 } else { 3106 /* 3107 * Bump the reference counts for objects on this DAG. If 3108 * this is the first dlopen() call for the object that was 3109 * already loaded as a dependency, initialize the dag 3110 * starting at it. 3111 */ 3112 init_dag(obj); 3113 ref_dag(obj); 3114 3115 if ((lo_flags & RTLD_LO_TRACE) != 0) 3116 goto trace; 3117 } 3118 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3119 obj->z_nodelete) && !obj->ref_nodel) { 3120 dbg("obj %s nodelete", obj->path); 3121 ref_dag(obj); 3122 obj->z_nodelete = obj->ref_nodel = true; 3123 } 3124 } 3125 3126 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3127 name); 3128 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3129 3130 if ((lo_flags & RTLD_LO_EARLY) == 0) { 3131 map_stacks_exec(lockstate); 3132 if (obj) 3133 distribute_static_tls(&initlist, lockstate); 3134 } 3135 3136 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3137 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3138 lockstate) == -1) { 3139 objlist_clear(&initlist); 3140 dlopen_cleanup(obj); 3141 if (lockstate == &mlockstate) 3142 lock_release(rtld_bind_lock, lockstate); 3143 return (NULL); 3144 } 3145 3146 if (!(lo_flags & RTLD_LO_EARLY)) { 3147 /* Call the init functions. */ 3148 objlist_call_init(&initlist, lockstate); 3149 } 3150 objlist_clear(&initlist); 3151 if (lockstate == &mlockstate) 3152 lock_release(rtld_bind_lock, lockstate); 3153 return obj; 3154 trace: 3155 trace_loaded_objects(obj); 3156 if (lockstate == &mlockstate) 3157 lock_release(rtld_bind_lock, lockstate); 3158 exit(0); 3159 } 3160 3161 static void * 3162 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3163 int flags) 3164 { 3165 DoneList donelist; 3166 const Obj_Entry *obj, *defobj; 3167 const Elf_Sym *def; 3168 SymLook req; 3169 RtldLockState lockstate; 3170 tls_index ti; 3171 int res; 3172 3173 def = NULL; 3174 defobj = NULL; 3175 symlook_init(&req, name); 3176 req.ventry = ve; 3177 req.flags = flags | SYMLOOK_IN_PLT; 3178 req.lockstate = &lockstate; 3179 3180 rlock_acquire(rtld_bind_lock, &lockstate); 3181 if (sigsetjmp(lockstate.env, 0) != 0) 3182 lock_upgrade(rtld_bind_lock, &lockstate); 3183 if (handle == NULL || handle == RTLD_NEXT || 3184 handle == RTLD_DEFAULT || handle == RTLD_SELF || 3185 handle == RTLD_ALL) { 3186 3187 if (handle != RTLD_ALL) { 3188 if ((obj = obj_from_addr(retaddr)) == NULL) { 3189 _rtld_error("Cannot determine caller's shared object"); 3190 lock_release(rtld_bind_lock, &lockstate); 3191 return NULL; 3192 } 3193 } else { 3194 obj = obj_list; 3195 } 3196 if (handle == NULL) { /* Just the caller's shared object. */ 3197 res = symlook_obj(&req, obj); 3198 if (res == 0) { 3199 def = req.sym_out; 3200 defobj = req.defobj_out; 3201 } 3202 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3203 handle == RTLD_SELF || /* ... caller included */ 3204 handle == RTLD_ALL) { /* All Objects */ 3205 if (handle == RTLD_NEXT) 3206 obj = obj->next; 3207 for (; obj != NULL; obj = obj->next) { 3208 res = symlook_obj(&req, obj); 3209 if (res == 0) { 3210 if (def == NULL || 3211 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3212 def = req.sym_out; 3213 defobj = req.defobj_out; 3214 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3215 break; 3216 } 3217 } 3218 } 3219 /* 3220 * Search the dynamic linker itself, and possibly resolve the 3221 * symbol from there. This is how the application links to 3222 * dynamic linker services such as dlopen. 3223 */ 3224 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3225 res = symlook_obj(&req, &obj_rtld); 3226 if (res == 0) { 3227 def = req.sym_out; 3228 defobj = req.defobj_out; 3229 } 3230 } 3231 } else { 3232 assert(handle == RTLD_DEFAULT); 3233 res = symlook_default(&req, obj); 3234 if (res == 0) { 3235 defobj = req.defobj_out; 3236 def = req.sym_out; 3237 } 3238 } 3239 } else { 3240 if ((obj = dlcheck(handle)) == NULL) { 3241 lock_release(rtld_bind_lock, &lockstate); 3242 return NULL; 3243 } 3244 3245 donelist_init(&donelist); 3246 if (obj->mainprog) { 3247 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3248 res = symlook_global(&req, &donelist); 3249 if (res == 0) { 3250 def = req.sym_out; 3251 defobj = req.defobj_out; 3252 } 3253 /* 3254 * Search the dynamic linker itself, and possibly resolve the 3255 * symbol from there. This is how the application links to 3256 * dynamic linker services such as dlopen. 3257 */ 3258 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3259 res = symlook_obj(&req, &obj_rtld); 3260 if (res == 0) { 3261 def = req.sym_out; 3262 defobj = req.defobj_out; 3263 } 3264 } 3265 } 3266 else { 3267 /* Search the whole DAG rooted at the given object. */ 3268 res = symlook_list(&req, &obj->dagmembers, &donelist); 3269 if (res == 0) { 3270 def = req.sym_out; 3271 defobj = req.defobj_out; 3272 } 3273 } 3274 } 3275 3276 if (def != NULL) { 3277 lock_release(rtld_bind_lock, &lockstate); 3278 3279 /* 3280 * The value required by the caller is derived from the value 3281 * of the symbol. this is simply the relocated value of the 3282 * symbol. 3283 */ 3284 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3285 return (make_function_pointer(def, defobj)); 3286 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3287 return (rtld_resolve_ifunc(defobj, def)); 3288 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3289 ti.ti_module = defobj->tlsindex; 3290 ti.ti_offset = def->st_value; 3291 return (__tls_get_addr(&ti)); 3292 } else 3293 return (defobj->relocbase + def->st_value); 3294 } 3295 3296 _rtld_error("Undefined symbol \"%s\"", name); 3297 lock_release(rtld_bind_lock, &lockstate); 3298 return NULL; 3299 } 3300 3301 void * 3302 dlsym(void *handle, const char *name) 3303 { 3304 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3305 SYMLOOK_DLSYM); 3306 } 3307 3308 dlfunc_t 3309 dlfunc(void *handle, const char *name) 3310 { 3311 union { 3312 void *d; 3313 dlfunc_t f; 3314 } rv; 3315 3316 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3317 SYMLOOK_DLSYM); 3318 return (rv.f); 3319 } 3320 3321 void * 3322 dlvsym(void *handle, const char *name, const char *version) 3323 { 3324 Ver_Entry ventry; 3325 3326 ventry.name = version; 3327 ventry.file = NULL; 3328 ventry.hash = elf_hash(version); 3329 ventry.flags= 0; 3330 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3331 SYMLOOK_DLSYM); 3332 } 3333 3334 int 3335 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3336 { 3337 const Obj_Entry *obj; 3338 RtldLockState lockstate; 3339 3340 rlock_acquire(rtld_bind_lock, &lockstate); 3341 obj = obj_from_addr(addr); 3342 if (obj == NULL) { 3343 _rtld_error("No shared object contains address"); 3344 lock_release(rtld_bind_lock, &lockstate); 3345 return (0); 3346 } 3347 rtld_fill_dl_phdr_info(obj, phdr_info); 3348 lock_release(rtld_bind_lock, &lockstate); 3349 return (1); 3350 } 3351 3352 int 3353 dladdr(const void *addr, Dl_info *info) 3354 { 3355 const Obj_Entry *obj; 3356 const Elf_Sym *def; 3357 void *symbol_addr; 3358 unsigned long symoffset; 3359 RtldLockState lockstate; 3360 3361 rlock_acquire(rtld_bind_lock, &lockstate); 3362 obj = obj_from_addr(addr); 3363 if (obj == NULL) { 3364 _rtld_error("No shared object contains address"); 3365 lock_release(rtld_bind_lock, &lockstate); 3366 return 0; 3367 } 3368 info->dli_fname = obj->path; 3369 info->dli_fbase = obj->mapbase; 3370 info->dli_saddr = NULL; 3371 info->dli_sname = NULL; 3372 3373 /* 3374 * Walk the symbol list looking for the symbol whose address is 3375 * closest to the address sent in. 3376 */ 3377 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3378 def = obj->symtab + symoffset; 3379 3380 /* 3381 * For skip the symbol if st_shndx is either SHN_UNDEF or 3382 * SHN_COMMON. 3383 */ 3384 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3385 continue; 3386 3387 /* 3388 * If the symbol is greater than the specified address, or if it 3389 * is further away from addr than the current nearest symbol, 3390 * then reject it. 3391 */ 3392 symbol_addr = obj->relocbase + def->st_value; 3393 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3394 continue; 3395 3396 /* Update our idea of the nearest symbol. */ 3397 info->dli_sname = obj->strtab + def->st_name; 3398 info->dli_saddr = symbol_addr; 3399 3400 /* Exact match? */ 3401 if (info->dli_saddr == addr) 3402 break; 3403 } 3404 lock_release(rtld_bind_lock, &lockstate); 3405 return 1; 3406 } 3407 3408 int 3409 dlinfo(void *handle, int request, void *p) 3410 { 3411 const Obj_Entry *obj; 3412 RtldLockState lockstate; 3413 int error; 3414 3415 rlock_acquire(rtld_bind_lock, &lockstate); 3416 3417 if (handle == NULL || handle == RTLD_SELF) { 3418 void *retaddr; 3419 3420 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3421 if ((obj = obj_from_addr(retaddr)) == NULL) 3422 _rtld_error("Cannot determine caller's shared object"); 3423 } else 3424 obj = dlcheck(handle); 3425 3426 if (obj == NULL) { 3427 lock_release(rtld_bind_lock, &lockstate); 3428 return (-1); 3429 } 3430 3431 error = 0; 3432 switch (request) { 3433 case RTLD_DI_LINKMAP: 3434 *((struct link_map const **)p) = &obj->linkmap; 3435 break; 3436 case RTLD_DI_ORIGIN: 3437 error = rtld_dirname(obj->path, p); 3438 break; 3439 3440 case RTLD_DI_SERINFOSIZE: 3441 case RTLD_DI_SERINFO: 3442 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3443 break; 3444 3445 default: 3446 _rtld_error("Invalid request %d passed to dlinfo()", request); 3447 error = -1; 3448 } 3449 3450 lock_release(rtld_bind_lock, &lockstate); 3451 3452 return (error); 3453 } 3454 3455 static void 3456 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3457 { 3458 3459 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3460 phdr_info->dlpi_name = obj->path; 3461 phdr_info->dlpi_phdr = obj->phdr; 3462 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3463 phdr_info->dlpi_tls_modid = obj->tlsindex; 3464 phdr_info->dlpi_tls_data = obj->tlsinit; 3465 phdr_info->dlpi_adds = obj_loads; 3466 phdr_info->dlpi_subs = obj_loads - obj_count; 3467 } 3468 3469 int 3470 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3471 { 3472 struct dl_phdr_info phdr_info; 3473 const Obj_Entry *obj; 3474 RtldLockState bind_lockstate, phdr_lockstate; 3475 int error; 3476 3477 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3478 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3479 3480 error = 0; 3481 3482 for (obj = obj_list; obj != NULL; obj = obj->next) { 3483 rtld_fill_dl_phdr_info(obj, &phdr_info); 3484 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3485 break; 3486 3487 } 3488 if (error == 0) { 3489 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3490 error = callback(&phdr_info, sizeof(phdr_info), param); 3491 } 3492 3493 lock_release(rtld_bind_lock, &bind_lockstate); 3494 lock_release(rtld_phdr_lock, &phdr_lockstate); 3495 3496 return (error); 3497 } 3498 3499 static void * 3500 fill_search_info(const char *dir, size_t dirlen, void *param) 3501 { 3502 struct fill_search_info_args *arg; 3503 3504 arg = param; 3505 3506 if (arg->request == RTLD_DI_SERINFOSIZE) { 3507 arg->serinfo->dls_cnt ++; 3508 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3509 } else { 3510 struct dl_serpath *s_entry; 3511 3512 s_entry = arg->serpath; 3513 s_entry->dls_name = arg->strspace; 3514 s_entry->dls_flags = arg->flags; 3515 3516 strncpy(arg->strspace, dir, dirlen); 3517 arg->strspace[dirlen] = '\0'; 3518 3519 arg->strspace += dirlen + 1; 3520 arg->serpath++; 3521 } 3522 3523 return (NULL); 3524 } 3525 3526 static int 3527 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3528 { 3529 struct dl_serinfo _info; 3530 struct fill_search_info_args args; 3531 3532 args.request = RTLD_DI_SERINFOSIZE; 3533 args.serinfo = &_info; 3534 3535 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3536 _info.dls_cnt = 0; 3537 3538 path_enumerate(obj->rpath, fill_search_info, &args); 3539 path_enumerate(ld_library_path, fill_search_info, &args); 3540 path_enumerate(obj->runpath, fill_search_info, &args); 3541 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3542 if (!obj->z_nodeflib) 3543 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3544 3545 3546 if (request == RTLD_DI_SERINFOSIZE) { 3547 info->dls_size = _info.dls_size; 3548 info->dls_cnt = _info.dls_cnt; 3549 return (0); 3550 } 3551 3552 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3553 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3554 return (-1); 3555 } 3556 3557 args.request = RTLD_DI_SERINFO; 3558 args.serinfo = info; 3559 args.serpath = &info->dls_serpath[0]; 3560 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3561 3562 args.flags = LA_SER_RUNPATH; 3563 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3564 return (-1); 3565 3566 args.flags = LA_SER_LIBPATH; 3567 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3568 return (-1); 3569 3570 args.flags = LA_SER_RUNPATH; 3571 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3572 return (-1); 3573 3574 args.flags = LA_SER_CONFIG; 3575 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3576 != NULL) 3577 return (-1); 3578 3579 args.flags = LA_SER_DEFAULT; 3580 if (!obj->z_nodeflib && 3581 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3582 return (-1); 3583 return (0); 3584 } 3585 3586 static int 3587 rtld_dirname(const char *path, char *bname) 3588 { 3589 const char *endp; 3590 3591 /* Empty or NULL string gets treated as "." */ 3592 if (path == NULL || *path == '\0') { 3593 bname[0] = '.'; 3594 bname[1] = '\0'; 3595 return (0); 3596 } 3597 3598 /* Strip trailing slashes */ 3599 endp = path + strlen(path) - 1; 3600 while (endp > path && *endp == '/') 3601 endp--; 3602 3603 /* Find the start of the dir */ 3604 while (endp > path && *endp != '/') 3605 endp--; 3606 3607 /* Either the dir is "/" or there are no slashes */ 3608 if (endp == path) { 3609 bname[0] = *endp == '/' ? '/' : '.'; 3610 bname[1] = '\0'; 3611 return (0); 3612 } else { 3613 do { 3614 endp--; 3615 } while (endp > path && *endp == '/'); 3616 } 3617 3618 if (endp - path + 2 > PATH_MAX) 3619 { 3620 _rtld_error("Filename is too long: %s", path); 3621 return(-1); 3622 } 3623 3624 strncpy(bname, path, endp - path + 1); 3625 bname[endp - path + 1] = '\0'; 3626 return (0); 3627 } 3628 3629 static int 3630 rtld_dirname_abs(const char *path, char *base) 3631 { 3632 char base_rel[PATH_MAX]; 3633 3634 if (rtld_dirname(path, base) == -1) 3635 return (-1); 3636 if (base[0] == '/') 3637 return (0); 3638 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3639 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3640 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3641 return (-1); 3642 strcpy(base, base_rel); 3643 return (0); 3644 } 3645 3646 static void 3647 linkmap_add(Obj_Entry *obj) 3648 { 3649 struct link_map *l = &obj->linkmap; 3650 struct link_map *prev; 3651 3652 obj->linkmap.l_name = obj->path; 3653 obj->linkmap.l_addr = obj->mapbase; 3654 obj->linkmap.l_ld = obj->dynamic; 3655 3656 if (r_debug.r_map == NULL) { 3657 r_debug.r_map = l; 3658 return; 3659 } 3660 3661 /* 3662 * Scan to the end of the list, but not past the entry for the 3663 * dynamic linker, which we want to keep at the very end. 3664 */ 3665 for (prev = r_debug.r_map; 3666 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3667 prev = prev->l_next) 3668 ; 3669 3670 /* Link in the new entry. */ 3671 l->l_prev = prev; 3672 l->l_next = prev->l_next; 3673 if (l->l_next != NULL) 3674 l->l_next->l_prev = l; 3675 prev->l_next = l; 3676 } 3677 3678 static void 3679 linkmap_delete(Obj_Entry *obj) 3680 { 3681 struct link_map *l = &obj->linkmap; 3682 3683 if (l->l_prev == NULL) { 3684 if ((r_debug.r_map = l->l_next) != NULL) 3685 l->l_next->l_prev = NULL; 3686 return; 3687 } 3688 3689 if ((l->l_prev->l_next = l->l_next) != NULL) 3690 l->l_next->l_prev = l->l_prev; 3691 } 3692 3693 /* 3694 * Function for the debugger to set a breakpoint on to gain control. 3695 * 3696 * The two parameters allow the debugger to easily find and determine 3697 * what the runtime loader is doing and to whom it is doing it. 3698 * 3699 * When the loadhook trap is hit (r_debug_state, set at program 3700 * initialization), the arguments can be found on the stack: 3701 * 3702 * +8 struct link_map *m 3703 * +4 struct r_debug *rd 3704 * +0 RetAddr 3705 */ 3706 void 3707 r_debug_state(struct r_debug* rd, struct link_map *m) 3708 { 3709 /* 3710 * The following is a hack to force the compiler to emit calls to 3711 * this function, even when optimizing. If the function is empty, 3712 * the compiler is not obliged to emit any code for calls to it, 3713 * even when marked __noinline. However, gdb depends on those 3714 * calls being made. 3715 */ 3716 __asm __volatile("" : : : "memory"); 3717 } 3718 3719 /* 3720 * A function called after init routines have completed. This can be used to 3721 * break before a program's entry routine is called, and can be used when 3722 * main is not available in the symbol table. 3723 */ 3724 void 3725 _r_debug_postinit(struct link_map *m) 3726 { 3727 3728 /* See r_debug_state(). */ 3729 __asm __volatile("" : : : "memory"); 3730 } 3731 3732 /* 3733 * Get address of the pointer variable in the main program. 3734 * Prefer non-weak symbol over the weak one. 3735 */ 3736 static const void ** 3737 get_program_var_addr(const char *name, RtldLockState *lockstate) 3738 { 3739 SymLook req; 3740 DoneList donelist; 3741 3742 symlook_init(&req, name); 3743 req.lockstate = lockstate; 3744 donelist_init(&donelist); 3745 if (symlook_global(&req, &donelist) != 0) 3746 return (NULL); 3747 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3748 return ((const void **)make_function_pointer(req.sym_out, 3749 req.defobj_out)); 3750 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3751 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3752 else 3753 return ((const void **)(req.defobj_out->relocbase + 3754 req.sym_out->st_value)); 3755 } 3756 3757 /* 3758 * Set a pointer variable in the main program to the given value. This 3759 * is used to set key variables such as "environ" before any of the 3760 * init functions are called. 3761 */ 3762 static void 3763 set_program_var(const char *name, const void *value) 3764 { 3765 const void **addr; 3766 3767 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3768 dbg("\"%s\": *%p <-- %p", name, addr, value); 3769 *addr = value; 3770 } 3771 } 3772 3773 /* 3774 * Search the global objects, including dependencies and main object, 3775 * for the given symbol. 3776 */ 3777 static int 3778 symlook_global(SymLook *req, DoneList *donelist) 3779 { 3780 SymLook req1; 3781 const Objlist_Entry *elm; 3782 int res; 3783 3784 symlook_init_from_req(&req1, req); 3785 3786 /* Search all objects loaded at program start up. */ 3787 if (req->defobj_out == NULL || 3788 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3789 res = symlook_list(&req1, &list_main, donelist); 3790 if (res == 0 && (req->defobj_out == NULL || 3791 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3792 req->sym_out = req1.sym_out; 3793 req->defobj_out = req1.defobj_out; 3794 assert(req->defobj_out != NULL); 3795 } 3796 } 3797 3798 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3799 STAILQ_FOREACH(elm, &list_global, link) { 3800 if (req->defobj_out != NULL && 3801 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3802 break; 3803 res = symlook_list(&req1, &elm->obj->dagmembers, 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 return (req->sym_out != NULL ? 0 : ESRCH); 3813 } 3814 3815 /* 3816 * This is a special version of getenv which is far more efficient 3817 * at finding LD_ environment vars. 3818 */ 3819 static 3820 const char * 3821 _getenv_ld(const char *id) 3822 { 3823 const char *envp; 3824 int i, j; 3825 int idlen = strlen(id); 3826 3827 if (ld_index == LD_ARY_CACHE) 3828 return(getenv(id)); 3829 if (ld_index == 0) { 3830 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 3831 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 3832 ld_ary[j++] = envp; 3833 } 3834 if (j == 0) 3835 ld_ary[j++] = ""; 3836 ld_index = j; 3837 } 3838 for (i = ld_index - 1; i >= 0; --i) { 3839 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 3840 return(ld_ary[i] + idlen + 1); 3841 } 3842 return(NULL); 3843 } 3844 3845 /* 3846 * Given a symbol name in a referencing object, find the corresponding 3847 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3848 * no definition was found. Returns a pointer to the Obj_Entry of the 3849 * defining object via the reference parameter DEFOBJ_OUT. 3850 */ 3851 static int 3852 symlook_default(SymLook *req, const Obj_Entry *refobj) 3853 { 3854 DoneList donelist; 3855 const Objlist_Entry *elm; 3856 SymLook req1; 3857 int res; 3858 3859 donelist_init(&donelist); 3860 symlook_init_from_req(&req1, req); 3861 3862 /* Look first in the referencing object if linked symbolically. */ 3863 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3864 res = symlook_obj(&req1, refobj); 3865 if (res == 0) { 3866 req->sym_out = req1.sym_out; 3867 req->defobj_out = req1.defobj_out; 3868 assert(req->defobj_out != NULL); 3869 } 3870 } 3871 3872 symlook_global(req, &donelist); 3873 3874 /* Search all dlopened DAGs containing the referencing object. */ 3875 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3876 if (req->sym_out != NULL && 3877 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3878 break; 3879 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3880 if (res == 0 && (req->sym_out == NULL || 3881 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3882 req->sym_out = req1.sym_out; 3883 req->defobj_out = req1.defobj_out; 3884 assert(req->defobj_out != NULL); 3885 } 3886 } 3887 3888 /* 3889 * Search the dynamic linker itself, and possibly resolve the 3890 * symbol from there. This is how the application links to 3891 * dynamic linker services such as dlopen. 3892 */ 3893 if (req->sym_out == NULL || 3894 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3895 res = symlook_obj(&req1, &obj_rtld); 3896 if (res == 0) { 3897 req->sym_out = req1.sym_out; 3898 req->defobj_out = req1.defobj_out; 3899 assert(req->defobj_out != NULL); 3900 } 3901 } 3902 3903 return (req->sym_out != NULL ? 0 : ESRCH); 3904 } 3905 3906 static int 3907 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3908 { 3909 const Elf_Sym *def; 3910 const Obj_Entry *defobj; 3911 const Objlist_Entry *elm; 3912 SymLook req1; 3913 int res; 3914 3915 def = NULL; 3916 defobj = NULL; 3917 STAILQ_FOREACH(elm, objlist, link) { 3918 if (donelist_check(dlp, elm->obj)) 3919 continue; 3920 symlook_init_from_req(&req1, req); 3921 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3922 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3923 def = req1.sym_out; 3924 defobj = req1.defobj_out; 3925 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3926 break; 3927 } 3928 } 3929 } 3930 if (def != NULL) { 3931 req->sym_out = def; 3932 req->defobj_out = defobj; 3933 return (0); 3934 } 3935 return (ESRCH); 3936 } 3937 3938 /* 3939 * Search the chain of DAGS cointed to by the given Needed_Entry 3940 * for a symbol of the given name. Each DAG is scanned completely 3941 * before advancing to the next one. Returns a pointer to the symbol, 3942 * or NULL if no definition was found. 3943 */ 3944 static int 3945 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3946 { 3947 const Elf_Sym *def; 3948 const Needed_Entry *n; 3949 const Obj_Entry *defobj; 3950 SymLook req1; 3951 int res; 3952 3953 def = NULL; 3954 defobj = NULL; 3955 symlook_init_from_req(&req1, req); 3956 for (n = needed; n != NULL; n = n->next) { 3957 if (n->obj == NULL || 3958 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3959 continue; 3960 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3961 def = req1.sym_out; 3962 defobj = req1.defobj_out; 3963 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3964 break; 3965 } 3966 } 3967 if (def != NULL) { 3968 req->sym_out = def; 3969 req->defobj_out = defobj; 3970 return (0); 3971 } 3972 return (ESRCH); 3973 } 3974 3975 /* 3976 * Search the symbol table of a single shared object for a symbol of 3977 * the given name and version, if requested. Returns a pointer to the 3978 * symbol, or NULL if no definition was found. If the object is 3979 * filter, return filtered symbol from filtee. 3980 * 3981 * The symbol's hash value is passed in for efficiency reasons; that 3982 * eliminates many recomputations of the hash value. 3983 */ 3984 int 3985 symlook_obj(SymLook *req, const Obj_Entry *obj) 3986 { 3987 DoneList donelist; 3988 SymLook req1; 3989 int flags, res, mres; 3990 3991 /* 3992 * If there is at least one valid hash at this point, we prefer to 3993 * use the faster GNU version if available. 3994 */ 3995 if (obj->valid_hash_gnu) 3996 mres = symlook_obj1_gnu(req, obj); 3997 else if (obj->valid_hash_sysv) 3998 mres = symlook_obj1_sysv(req, obj); 3999 else 4000 return (EINVAL); 4001 4002 if (mres == 0) { 4003 if (obj->needed_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_filtees, &donelist); 4009 if (res == 0) { 4010 req->sym_out = req1.sym_out; 4011 req->defobj_out = req1.defobj_out; 4012 } 4013 return (res); 4014 } 4015 if (obj->needed_aux_filtees != NULL) { 4016 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 4017 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 4018 donelist_init(&donelist); 4019 symlook_init_from_req(&req1, req); 4020 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 4021 if (res == 0) { 4022 req->sym_out = req1.sym_out; 4023 req->defobj_out = req1.defobj_out; 4024 return (res); 4025 } 4026 } 4027 } 4028 return (mres); 4029 } 4030 4031 /* Symbol match routine common to both hash functions */ 4032 static bool 4033 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4034 const unsigned long symnum) 4035 { 4036 Elf_Versym verndx; 4037 const Elf_Sym *symp; 4038 const char *strp; 4039 4040 symp = obj->symtab + symnum; 4041 strp = obj->strtab + symp->st_name; 4042 4043 switch (ELF_ST_TYPE(symp->st_info)) { 4044 case STT_FUNC: 4045 case STT_NOTYPE: 4046 case STT_OBJECT: 4047 case STT_COMMON: 4048 case STT_GNU_IFUNC: 4049 if (symp->st_value == 0) 4050 return (false); 4051 /* fallthrough */ 4052 case STT_TLS: 4053 if (symp->st_shndx != SHN_UNDEF) 4054 break; 4055 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4056 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4057 break; 4058 /* fallthrough */ 4059 default: 4060 return (false); 4061 } 4062 if (strcmp(req->name, strp) != 0) 4063 return (false); 4064 4065 if (req->ventry == NULL) { 4066 if (obj->versyms != NULL) { 4067 verndx = VER_NDX(obj->versyms[symnum]); 4068 if (verndx > obj->vernum) { 4069 _rtld_error( 4070 "%s: symbol %s references wrong version %d", 4071 obj->path, obj->strtab + symnum, verndx); 4072 return (false); 4073 } 4074 /* 4075 * If we are not called from dlsym (i.e. this 4076 * is a normal relocation from unversioned 4077 * binary), accept the symbol immediately if 4078 * it happens to have first version after this 4079 * shared object became versioned. Otherwise, 4080 * if symbol is versioned and not hidden, 4081 * remember it. If it is the only symbol with 4082 * this name exported by the shared object, it 4083 * will be returned as a match by the calling 4084 * function. If symbol is global (verndx < 2) 4085 * accept it unconditionally. 4086 */ 4087 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4088 verndx == VER_NDX_GIVEN) { 4089 result->sym_out = symp; 4090 return (true); 4091 } 4092 else if (verndx >= VER_NDX_GIVEN) { 4093 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4094 == 0) { 4095 if (result->vsymp == NULL) 4096 result->vsymp = symp; 4097 result->vcount++; 4098 } 4099 return (false); 4100 } 4101 } 4102 result->sym_out = symp; 4103 return (true); 4104 } 4105 if (obj->versyms == NULL) { 4106 if (object_match_name(obj, req->ventry->name)) { 4107 _rtld_error("%s: object %s should provide version %s " 4108 "for symbol %s", obj_rtld.path, obj->path, 4109 req->ventry->name, obj->strtab + symnum); 4110 return (false); 4111 } 4112 } else { 4113 verndx = VER_NDX(obj->versyms[symnum]); 4114 if (verndx > obj->vernum) { 4115 _rtld_error("%s: symbol %s references wrong version %d", 4116 obj->path, obj->strtab + symnum, verndx); 4117 return (false); 4118 } 4119 if (obj->vertab[verndx].hash != req->ventry->hash || 4120 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4121 /* 4122 * Version does not match. Look if this is a 4123 * global symbol and if it is not hidden. If 4124 * global symbol (verndx < 2) is available, 4125 * use it. Do not return symbol if we are 4126 * called by dlvsym, because dlvsym looks for 4127 * a specific version and default one is not 4128 * what dlvsym wants. 4129 */ 4130 if ((req->flags & SYMLOOK_DLSYM) || 4131 (verndx >= VER_NDX_GIVEN) || 4132 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4133 return (false); 4134 } 4135 } 4136 result->sym_out = symp; 4137 return (true); 4138 } 4139 4140 /* 4141 * Search for symbol using SysV hash function. 4142 * obj->buckets is known not to be NULL at this point; the test for this was 4143 * performed with the obj->valid_hash_sysv assignment. 4144 */ 4145 static int 4146 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4147 { 4148 unsigned long symnum; 4149 Sym_Match_Result matchres; 4150 4151 matchres.sym_out = NULL; 4152 matchres.vsymp = NULL; 4153 matchres.vcount = 0; 4154 4155 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4156 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4157 if (symnum >= obj->nchains) 4158 return (ESRCH); /* Bad object */ 4159 4160 if (matched_symbol(req, obj, &matchres, symnum)) { 4161 req->sym_out = matchres.sym_out; 4162 req->defobj_out = obj; 4163 return (0); 4164 } 4165 } 4166 if (matchres.vcount == 1) { 4167 req->sym_out = matchres.vsymp; 4168 req->defobj_out = obj; 4169 return (0); 4170 } 4171 return (ESRCH); 4172 } 4173 4174 /* Search for symbol using GNU hash function */ 4175 static int 4176 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4177 { 4178 Elf_Addr bloom_word; 4179 const Elf32_Word *hashval; 4180 Elf32_Word bucket; 4181 Sym_Match_Result matchres; 4182 unsigned int h1, h2; 4183 unsigned long symnum; 4184 4185 matchres.sym_out = NULL; 4186 matchres.vsymp = NULL; 4187 matchres.vcount = 0; 4188 4189 /* Pick right bitmask word from Bloom filter array */ 4190 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4191 obj->maskwords_bm_gnu]; 4192 4193 /* Calculate modulus word size of gnu hash and its derivative */ 4194 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4195 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4196 4197 /* Filter out the "definitely not in set" queries */ 4198 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4199 return (ESRCH); 4200 4201 /* Locate hash chain and corresponding value element*/ 4202 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4203 if (bucket == 0) 4204 return (ESRCH); 4205 hashval = &obj->chain_zero_gnu[bucket]; 4206 do { 4207 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4208 symnum = hashval - obj->chain_zero_gnu; 4209 if (matched_symbol(req, obj, &matchres, symnum)) { 4210 req->sym_out = matchres.sym_out; 4211 req->defobj_out = obj; 4212 return (0); 4213 } 4214 } 4215 } while ((*hashval++ & 1) == 0); 4216 if (matchres.vcount == 1) { 4217 req->sym_out = matchres.vsymp; 4218 req->defobj_out = obj; 4219 return (0); 4220 } 4221 return (ESRCH); 4222 } 4223 4224 static void 4225 trace_loaded_objects(Obj_Entry *obj) 4226 { 4227 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4228 int c; 4229 4230 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4231 main_local = ""; 4232 4233 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4234 fmt1 = "\t%o => %p (%x)\n"; 4235 4236 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4237 fmt2 = "\t%o (%x)\n"; 4238 4239 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 4240 4241 for (; obj; obj = obj->next) { 4242 Needed_Entry *needed; 4243 char *name, *path; 4244 bool is_lib; 4245 4246 if (list_containers && obj->needed != NULL) 4247 rtld_printf("%s:\n", obj->path); 4248 for (needed = obj->needed; needed; needed = needed->next) { 4249 if (needed->obj != NULL) { 4250 if (needed->obj->traced && !list_containers) 4251 continue; 4252 needed->obj->traced = true; 4253 path = needed->obj->path; 4254 } else 4255 path = "not found"; 4256 4257 name = (char *)obj->strtab + needed->name; 4258 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4259 4260 fmt = is_lib ? fmt1 : fmt2; 4261 while ((c = *fmt++) != '\0') { 4262 switch (c) { 4263 default: 4264 rtld_putchar(c); 4265 continue; 4266 case '\\': 4267 switch (c = *fmt) { 4268 case '\0': 4269 continue; 4270 case 'n': 4271 rtld_putchar('\n'); 4272 break; 4273 case 't': 4274 rtld_putchar('\t'); 4275 break; 4276 } 4277 break; 4278 case '%': 4279 switch (c = *fmt) { 4280 case '\0': 4281 continue; 4282 case '%': 4283 default: 4284 rtld_putchar(c); 4285 break; 4286 case 'A': 4287 rtld_putstr(main_local); 4288 break; 4289 case 'a': 4290 rtld_putstr(obj_main->path); 4291 break; 4292 case 'o': 4293 rtld_putstr(name); 4294 break; 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 */ 4317 static void 4318 unload_object(Obj_Entry *root) 4319 { 4320 Obj_Entry *obj; 4321 Obj_Entry **linkp; 4322 4323 assert(root->refcount == 0); 4324 4325 /* 4326 * Pass over the DAG removing unreferenced objects from 4327 * appropriate lists. 4328 */ 4329 unlink_object(root); 4330 4331 /* Unmap all objects that are no longer referenced. */ 4332 linkp = &obj_list->next; 4333 while ((obj = *linkp) != NULL) { 4334 if (obj->refcount == 0) { 4335 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4336 obj->path); 4337 dbg("unloading \"%s\"", obj->path); 4338 unload_filtees(root); 4339 munmap(obj->mapbase, obj->mapsize); 4340 linkmap_delete(obj); 4341 *linkp = obj->next; 4342 obj_count--; 4343 obj_free(obj); 4344 } else 4345 linkp = &obj->next; 4346 } 4347 obj_tail = linkp; 4348 } 4349 4350 static void 4351 unlink_object(Obj_Entry *root) 4352 { 4353 Objlist_Entry *elm; 4354 4355 if (root->refcount == 0) { 4356 /* Remove the object from the RTLD_GLOBAL list. */ 4357 objlist_remove(&list_global, root); 4358 4359 /* Remove the object from all objects' DAG lists. */ 4360 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4361 objlist_remove(&elm->obj->dldags, root); 4362 if (elm->obj != root) 4363 unlink_object(elm->obj); 4364 } 4365 } 4366 } 4367 4368 static void 4369 ref_dag(Obj_Entry *root) 4370 { 4371 Objlist_Entry *elm; 4372 4373 assert(root->dag_inited); 4374 STAILQ_FOREACH(elm, &root->dagmembers, link) 4375 elm->obj->refcount++; 4376 } 4377 4378 static void 4379 unref_dag(Obj_Entry *root) 4380 { 4381 Objlist_Entry *elm; 4382 4383 assert(root->dag_inited); 4384 STAILQ_FOREACH(elm, &root->dagmembers, link) 4385 elm->obj->refcount--; 4386 } 4387 4388 /* 4389 * Common code for MD __tls_get_addr(). 4390 */ 4391 void * 4392 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 4393 { 4394 Elf_Addr* dtv = *dtvp; 4395 RtldLockState lockstate; 4396 4397 /* Check dtv generation in case new modules have arrived */ 4398 if (dtv[0] != tls_dtv_generation) { 4399 Elf_Addr* newdtv; 4400 int to_copy; 4401 4402 wlock_acquire(rtld_bind_lock, &lockstate); 4403 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4404 to_copy = dtv[1]; 4405 if (to_copy > tls_max_index) 4406 to_copy = tls_max_index; 4407 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4408 newdtv[0] = tls_dtv_generation; 4409 newdtv[1] = tls_max_index; 4410 free(dtv); 4411 lock_release(rtld_bind_lock, &lockstate); 4412 dtv = *dtvp = newdtv; 4413 } 4414 4415 /* Dynamically allocate module TLS if necessary */ 4416 if (!dtv[index + 1]) { 4417 /* Signal safe, wlock will block out signals. */ 4418 wlock_acquire(rtld_bind_lock, &lockstate); 4419 if (!dtv[index + 1]) 4420 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4421 lock_release(rtld_bind_lock, &lockstate); 4422 } 4423 return ((void *)(dtv[index + 1] + offset)); 4424 } 4425 4426 #if defined(RTLD_STATIC_TLS_VARIANT_II) 4427 4428 /* 4429 * Allocate the static TLS area. Return a pointer to the TCB. The 4430 * static area is based on negative offsets relative to the tcb. 4431 * 4432 * The TCB contains an errno pointer for the system call layer, but because 4433 * we are the RTLD we really have no idea how the caller was compiled so 4434 * the information has to be passed in. errno can either be: 4435 * 4436 * type 0 errno is a simple non-TLS global pointer. 4437 * (special case for e.g. libc_rtld) 4438 * type 1 errno accessed by GOT entry (dynamically linked programs) 4439 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 4440 */ 4441 struct tls_tcb * 4442 allocate_tls(Obj_Entry *objs) 4443 { 4444 Obj_Entry *obj; 4445 size_t data_size; 4446 size_t dtv_size; 4447 struct tls_tcb *tcb; 4448 Elf_Addr *dtv; 4449 Elf_Addr addr; 4450 4451 /* 4452 * Allocate the new TCB. static TLS storage is placed just before the 4453 * TCB to support the %gs:OFFSET (negative offset) model. 4454 */ 4455 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4456 ~RTLD_STATIC_TLS_ALIGN_MASK; 4457 tcb = malloc(data_size + sizeof(*tcb)); 4458 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 4459 4460 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 4461 dtv = malloc(dtv_size); 4462 bzero(dtv, dtv_size); 4463 4464 #ifdef RTLD_TCB_HAS_SELF_POINTER 4465 tcb->tcb_self = tcb; 4466 #endif 4467 tcb->tcb_dtv = dtv; 4468 tcb->tcb_pthread = NULL; 4469 4470 dtv[0] = tls_dtv_generation; 4471 dtv[1] = tls_max_index; 4472 4473 for (obj = objs; obj; obj = obj->next) { 4474 if (obj->tlsoffset) { 4475 addr = (Elf_Addr)tcb - obj->tlsoffset; 4476 memset((void *)(addr + obj->tlsinitsize), 4477 0, obj->tlssize - obj->tlsinitsize); 4478 if (obj->tlsinit) { 4479 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4480 obj->static_tls_copied = true; 4481 } 4482 dtv[obj->tlsindex + 1] = addr; 4483 } 4484 } 4485 return(tcb); 4486 } 4487 4488 void 4489 free_tls(struct tls_tcb *tcb) 4490 { 4491 Elf_Addr *dtv; 4492 int dtv_size, i; 4493 Elf_Addr tls_start, tls_end; 4494 size_t data_size; 4495 4496 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4497 ~RTLD_STATIC_TLS_ALIGN_MASK; 4498 4499 dtv = tcb->tcb_dtv; 4500 dtv_size = dtv[1]; 4501 tls_end = (Elf_Addr)tcb; 4502 tls_start = (Elf_Addr)tcb - data_size; 4503 for (i = 0; i < dtv_size; i++) { 4504 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 4505 free((void *)dtv[i+2]); 4506 } 4507 } 4508 free(dtv); 4509 4510 free((void*) tls_start); 4511 } 4512 4513 #else 4514 #error "Unsupported TLS layout" 4515 #endif 4516 4517 /* 4518 * Allocate TLS block for module with given index. 4519 */ 4520 void * 4521 allocate_module_tls(int index) 4522 { 4523 Obj_Entry* obj; 4524 char* p; 4525 4526 for (obj = obj_list; obj; obj = obj->next) { 4527 if (obj->tlsindex == index) 4528 break; 4529 } 4530 if (!obj) { 4531 _rtld_error("Can't find module with TLS index %d", index); 4532 die(); 4533 } 4534 4535 p = malloc(obj->tlssize); 4536 if (p == NULL) { 4537 _rtld_error("Cannot allocate TLS block for index %d", index); 4538 die(); 4539 } 4540 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4541 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4542 4543 return p; 4544 } 4545 4546 bool 4547 allocate_tls_offset(Obj_Entry *obj) 4548 { 4549 size_t off; 4550 4551 if (obj->tls_done) 4552 return true; 4553 4554 if (obj->tlssize == 0) { 4555 obj->tls_done = true; 4556 return true; 4557 } 4558 4559 if (obj->tlsindex == 1) 4560 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4561 else 4562 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4563 obj->tlssize, obj->tlsalign); 4564 4565 /* 4566 * If we have already fixed the size of the static TLS block, we 4567 * must stay within that size. When allocating the static TLS, we 4568 * leave a small amount of space spare to be used for dynamically 4569 * loading modules which use static TLS. 4570 */ 4571 if (tls_static_space) { 4572 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4573 return false; 4574 } 4575 4576 tls_last_offset = obj->tlsoffset = off; 4577 tls_last_size = obj->tlssize; 4578 obj->tls_done = true; 4579 4580 return true; 4581 } 4582 4583 void 4584 free_tls_offset(Obj_Entry *obj) 4585 { 4586 #ifdef RTLD_STATIC_TLS_VARIANT_II 4587 /* 4588 * If we were the last thing to allocate out of the static TLS 4589 * block, we give our space back to the 'allocator'. This is a 4590 * simplistic workaround to allow libGL.so.1 to be loaded and 4591 * unloaded multiple times. We only handle the Variant II 4592 * mechanism for now - this really needs a proper allocator. 4593 */ 4594 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4595 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4596 tls_last_offset -= obj->tlssize; 4597 tls_last_size = 0; 4598 } 4599 #endif 4600 } 4601 4602 struct tls_tcb * 4603 _rtld_allocate_tls(void) 4604 { 4605 struct tls_tcb *new_tcb; 4606 RtldLockState lockstate; 4607 4608 wlock_acquire(rtld_bind_lock, &lockstate); 4609 new_tcb = allocate_tls(obj_list); 4610 lock_release(rtld_bind_lock, &lockstate); 4611 4612 return (new_tcb); 4613 } 4614 4615 void 4616 _rtld_free_tls(struct tls_tcb *tcb) 4617 { 4618 RtldLockState lockstate; 4619 4620 wlock_acquire(rtld_bind_lock, &lockstate); 4621 free_tls(tcb); 4622 lock_release(rtld_bind_lock, &lockstate); 4623 } 4624 4625 static void 4626 object_add_name(Obj_Entry *obj, const char *name) 4627 { 4628 Name_Entry *entry; 4629 size_t len; 4630 4631 len = strlen(name); 4632 entry = malloc(sizeof(Name_Entry) + len); 4633 4634 if (entry != NULL) { 4635 strcpy(entry->name, name); 4636 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4637 } 4638 } 4639 4640 static int 4641 object_match_name(const Obj_Entry *obj, const char *name) 4642 { 4643 Name_Entry *entry; 4644 4645 STAILQ_FOREACH(entry, &obj->names, link) { 4646 if (strcmp(name, entry->name) == 0) 4647 return (1); 4648 } 4649 return (0); 4650 } 4651 4652 static Obj_Entry * 4653 locate_dependency(const Obj_Entry *obj, const char *name) 4654 { 4655 const Objlist_Entry *entry; 4656 const Needed_Entry *needed; 4657 4658 STAILQ_FOREACH(entry, &list_main, link) { 4659 if (object_match_name(entry->obj, name)) 4660 return entry->obj; 4661 } 4662 4663 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4664 if (strcmp(obj->strtab + needed->name, name) == 0 || 4665 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4666 /* 4667 * If there is DT_NEEDED for the name we are looking for, 4668 * we are all set. Note that object might not be found if 4669 * dependency was not loaded yet, so the function can 4670 * return NULL here. This is expected and handled 4671 * properly by the caller. 4672 */ 4673 return (needed->obj); 4674 } 4675 } 4676 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4677 obj->path, name); 4678 die(); 4679 } 4680 4681 static int 4682 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4683 const Elf_Vernaux *vna) 4684 { 4685 const Elf_Verdef *vd; 4686 const char *vername; 4687 4688 vername = refobj->strtab + vna->vna_name; 4689 vd = depobj->verdef; 4690 if (vd == NULL) { 4691 _rtld_error("%s: version %s required by %s not defined", 4692 depobj->path, vername, refobj->path); 4693 return (-1); 4694 } 4695 for (;;) { 4696 if (vd->vd_version != VER_DEF_CURRENT) { 4697 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4698 depobj->path, vd->vd_version); 4699 return (-1); 4700 } 4701 if (vna->vna_hash == vd->vd_hash) { 4702 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4703 ((char *)vd + vd->vd_aux); 4704 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4705 return (0); 4706 } 4707 if (vd->vd_next == 0) 4708 break; 4709 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4710 } 4711 if (vna->vna_flags & VER_FLG_WEAK) 4712 return (0); 4713 _rtld_error("%s: version %s required by %s not found", 4714 depobj->path, vername, refobj->path); 4715 return (-1); 4716 } 4717 4718 static int 4719 rtld_verify_object_versions(Obj_Entry *obj) 4720 { 4721 const Elf_Verneed *vn; 4722 const Elf_Verdef *vd; 4723 const Elf_Verdaux *vda; 4724 const Elf_Vernaux *vna; 4725 const Obj_Entry *depobj; 4726 int maxvernum, vernum; 4727 4728 if (obj->ver_checked) 4729 return (0); 4730 obj->ver_checked = true; 4731 4732 maxvernum = 0; 4733 /* 4734 * Walk over defined and required version records and figure out 4735 * max index used by any of them. Do very basic sanity checking 4736 * while there. 4737 */ 4738 vn = obj->verneed; 4739 while (vn != NULL) { 4740 if (vn->vn_version != VER_NEED_CURRENT) { 4741 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4742 obj->path, vn->vn_version); 4743 return (-1); 4744 } 4745 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4746 for (;;) { 4747 vernum = VER_NEED_IDX(vna->vna_other); 4748 if (vernum > maxvernum) 4749 maxvernum = vernum; 4750 if (vna->vna_next == 0) 4751 break; 4752 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4753 } 4754 if (vn->vn_next == 0) 4755 break; 4756 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4757 } 4758 4759 vd = obj->verdef; 4760 while (vd != NULL) { 4761 if (vd->vd_version != VER_DEF_CURRENT) { 4762 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4763 obj->path, vd->vd_version); 4764 return (-1); 4765 } 4766 vernum = VER_DEF_IDX(vd->vd_ndx); 4767 if (vernum > maxvernum) 4768 maxvernum = vernum; 4769 if (vd->vd_next == 0) 4770 break; 4771 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4772 } 4773 4774 if (maxvernum == 0) 4775 return (0); 4776 4777 /* 4778 * Store version information in array indexable by version index. 4779 * Verify that object version requirements are satisfied along the 4780 * way. 4781 */ 4782 obj->vernum = maxvernum + 1; 4783 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4784 4785 vd = obj->verdef; 4786 while (vd != NULL) { 4787 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4788 vernum = VER_DEF_IDX(vd->vd_ndx); 4789 assert(vernum <= maxvernum); 4790 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4791 obj->vertab[vernum].hash = vd->vd_hash; 4792 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4793 obj->vertab[vernum].file = NULL; 4794 obj->vertab[vernum].flags = 0; 4795 } 4796 if (vd->vd_next == 0) 4797 break; 4798 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4799 } 4800 4801 vn = obj->verneed; 4802 while (vn != NULL) { 4803 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4804 if (depobj == NULL) 4805 return (-1); 4806 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4807 for (;;) { 4808 if (check_object_provided_version(obj, depobj, vna)) 4809 return (-1); 4810 vernum = VER_NEED_IDX(vna->vna_other); 4811 assert(vernum <= maxvernum); 4812 obj->vertab[vernum].hash = vna->vna_hash; 4813 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4814 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4815 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4816 VER_INFO_HIDDEN : 0; 4817 if (vna->vna_next == 0) 4818 break; 4819 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4820 } 4821 if (vn->vn_next == 0) 4822 break; 4823 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4824 } 4825 return 0; 4826 } 4827 4828 static int 4829 rtld_verify_versions(const Objlist *objlist) 4830 { 4831 Objlist_Entry *entry; 4832 int rc; 4833 4834 rc = 0; 4835 STAILQ_FOREACH(entry, objlist, link) { 4836 /* 4837 * Skip dummy objects or objects that have their version requirements 4838 * already checked. 4839 */ 4840 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4841 continue; 4842 if (rtld_verify_object_versions(entry->obj) == -1) { 4843 rc = -1; 4844 if (ld_tracing == NULL) 4845 break; 4846 } 4847 } 4848 if (rc == 0 || ld_tracing != NULL) 4849 rc = rtld_verify_object_versions(&obj_rtld); 4850 return rc; 4851 } 4852 4853 const Ver_Entry * 4854 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4855 { 4856 Elf_Versym vernum; 4857 4858 if (obj->vertab) { 4859 vernum = VER_NDX(obj->versyms[symnum]); 4860 if (vernum >= obj->vernum) { 4861 _rtld_error("%s: symbol %s has wrong verneed value %d", 4862 obj->path, obj->strtab + symnum, vernum); 4863 } else if (obj->vertab[vernum].hash != 0) { 4864 return &obj->vertab[vernum]; 4865 } 4866 } 4867 return NULL; 4868 } 4869 4870 int 4871 _rtld_get_stack_prot(void) 4872 { 4873 4874 return (stack_prot); 4875 } 4876 4877 static void 4878 map_stacks_exec(RtldLockState *lockstate) 4879 { 4880 return; 4881 /* 4882 * Stack protection must be implemented in the kernel before the dynamic 4883 * linker can handle PT_GNU_STACK sections. 4884 * The following is the FreeBSD implementation of map_stacks_exec() 4885 * void (*thr_map_stacks_exec)(void); 4886 * 4887 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4888 * return; 4889 * thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4890 * get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4891 * if (thr_map_stacks_exec != NULL) { 4892 * stack_prot |= PROT_EXEC; 4893 * thr_map_stacks_exec(); 4894 * } 4895 */ 4896 } 4897 4898 /* 4899 * Only called after all primary shared libraries are loaded (EARLY is 4900 * not set). Resolves the static TLS distribution function at first-call. 4901 * This is typically a weak libc symbol that is overrideen by the threading 4902 * library. 4903 */ 4904 static void 4905 distribute_static_tls(Objlist *list, RtldLockState *lockstate) 4906 { 4907 Objlist_Entry *elm; 4908 Obj_Entry *obj; 4909 static void (*dtlsfunc)(size_t, void *, size_t, size_t); 4910 4911 /* 4912 * First time, resolve "_pthread_distribute_static_tls". 4913 */ 4914 if (dtlsfunc == NULL) { 4915 dtlsfunc = (void *)dlfunc(RTLD_ALL, 4916 "_pthread_distribute_static_tls"); 4917 if (dtlsfunc == NULL) 4918 return; 4919 } 4920 4921 /* 4922 * Initialize static TLS data for the object list using the callback 4923 * function (to either libc or pthreads). 4924 */ 4925 STAILQ_FOREACH(elm, list, link) { 4926 obj = elm->obj; 4927 if (/*obj->marker ||*/ !obj->tls_done || obj->static_tls_copied) 4928 continue; 4929 dtlsfunc(obj->tlsoffset, obj->tlsinit, 4930 obj->tlsinitsize, obj->tlssize); 4931 obj->static_tls_copied = true; 4932 } 4933 } 4934 4935 void 4936 symlook_init(SymLook *dst, const char *name) 4937 { 4938 4939 bzero(dst, sizeof(*dst)); 4940 dst->name = name; 4941 dst->hash = elf_hash(name); 4942 dst->hash_gnu = gnu_hash(name); 4943 } 4944 4945 static void 4946 symlook_init_from_req(SymLook *dst, const SymLook *src) 4947 { 4948 4949 dst->name = src->name; 4950 dst->hash = src->hash; 4951 dst->hash_gnu = src->hash_gnu; 4952 dst->ventry = src->ventry; 4953 dst->flags = src->flags; 4954 dst->defobj_out = NULL; 4955 dst->sym_out = NULL; 4956 dst->lockstate = src->lockstate; 4957 } 4958 4959 4960 /* 4961 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4962 */ 4963 static int 4964 parse_libdir(const char *str) 4965 { 4966 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4967 const char *orig; 4968 int fd; 4969 char c; 4970 4971 orig = str; 4972 fd = 0; 4973 for (c = *str; c != '\0'; c = *++str) { 4974 if (c < '0' || c > '9') 4975 return (-1); 4976 4977 fd *= RADIX; 4978 fd += c - '0'; 4979 } 4980 4981 /* Make sure we actually parsed something. */ 4982 if (str == orig) { 4983 _rtld_error("failed to parse directory FD from '%s'", str); 4984 return (-1); 4985 } 4986 return (fd); 4987 } 4988 4989 #ifdef ENABLE_OSRELDATE 4990 /* 4991 * Overrides for libc_pic-provided functions. 4992 */ 4993 4994 int 4995 __getosreldate(void) 4996 { 4997 size_t len; 4998 int oid[2]; 4999 int error, osrel; 5000 5001 if (osreldate != 0) 5002 return (osreldate); 5003 5004 oid[0] = CTL_KERN; 5005 oid[1] = KERN_OSRELDATE; 5006 osrel = 0; 5007 len = sizeof(osrel); 5008 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5009 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5010 osreldate = osrel; 5011 return (osreldate); 5012 } 5013 #endif 5014 5015 /* 5016 * No unresolved symbols for rtld. 5017 */ 5018 void 5019 __pthread_cxa_finalize(struct dl_phdr_info *a) 5020 { 5021 } 5022 5023 const char * 5024 rtld_strerror(int errnum) 5025 { 5026 5027 if (errnum < 0 || errnum >= sys_nerr) 5028 return ("Unknown error"); 5029 return (sys_errlist[errnum]); 5030 } 5031