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 Obj_Entry *dlcheck(void *); 89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 90 int lo_flags, int mode, RtldLockState *lockstate); 91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 93 static bool donelist_check(DoneList *, const Obj_Entry *); 94 static void errmsg_restore(char *); 95 static char *errmsg_save(void); 96 static void *fill_search_info(const char *, size_t, void *); 97 static char *find_library(const char *, const Obj_Entry *, int *); 98 static const char *gethints(bool); 99 static void init_dag(Obj_Entry *); 100 static void init_rtld(caddr_t, Elf_Auxinfo **); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static void linkmap_add(Obj_Entry *); 104 static void linkmap_delete(Obj_Entry *); 105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106 static void unload_filtees(Obj_Entry *); 107 static int load_needed_objects(Obj_Entry *, int); 108 static int load_preload_objects(void); 109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110 static void map_stacks_exec(RtldLockState *); 111 static Obj_Entry *obj_from_addr(const void *); 112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113 static void objlist_call_init(Objlist *, RtldLockState *); 114 static void objlist_clear(Objlist *); 115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116 static void objlist_init(Objlist *); 117 static void objlist_push_head(Objlist *, Obj_Entry *); 118 static void objlist_push_tail(Objlist *, Obj_Entry *); 119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120 static void objlist_remove(Objlist *, Obj_Entry *); 121 static int parse_libdir(const char *); 122 static void *path_enumerate(const char *, path_enum_proc, void *); 123 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 125 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 126 int flags, RtldLockState *lockstate); 127 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 128 RtldLockState *); 129 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 130 int flags, RtldLockState *lockstate); 131 static int rtld_dirname(const char *, char *); 132 static int rtld_dirname_abs(const char *, char *); 133 static void *rtld_dlopen(const char *name, int fd, int mode); 134 static void rtld_exit(void); 135 static char *search_library_path(const char *, const char *); 136 static char *search_library_pathfds(const char *, const char *, int *); 137 static const void **get_program_var_addr(const char *, RtldLockState *); 138 static void set_program_var(const char *, const void *); 139 static int symlook_default(SymLook *, const Obj_Entry *refobj); 140 static int symlook_global(SymLook *, DoneList *); 141 static void symlook_init_from_req(SymLook *, const SymLook *); 142 static int symlook_list(SymLook *, const Objlist *, DoneList *); 143 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 144 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 145 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 146 static void trace_loaded_objects(Obj_Entry *); 147 static void unlink_object(Obj_Entry *); 148 static void unload_object(Obj_Entry *); 149 static void unref_dag(Obj_Entry *); 150 static void ref_dag(Obj_Entry *); 151 static char *origin_subst_one(char *, const char *, const char *, bool); 152 static char *origin_subst(char *, const char *); 153 static void preinit_main(void); 154 static int rtld_verify_versions(const Objlist *); 155 static int rtld_verify_object_versions(Obj_Entry *); 156 static void object_add_name(Obj_Entry *, const char *); 157 static int object_match_name(const Obj_Entry *, const char *); 158 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 159 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 160 struct dl_phdr_info *phdr_info); 161 static uint_fast32_t gnu_hash (const char *); 162 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 163 const unsigned long); 164 165 void r_debug_state(struct r_debug *, struct link_map *) __noinline; 166 void _r_debug_postinit(struct link_map *) __noinline; 167 168 /* 169 * Data declarations. 170 */ 171 static char *error_message; /* Message for dlerror(), or NULL */ 172 struct r_debug r_debug; /* for GDB; */ 173 static bool libmap_disable; /* Disable libmap */ 174 static bool ld_loadfltr; /* Immediate filters processing */ 175 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 176 static bool trust; /* False for setuid and setgid programs */ 177 static bool dangerous_ld_env; /* True if environment variables have been 178 used to affect the libraries loaded */ 179 static const char *ld_bind_now; /* Environment variable for immediate binding */ 180 static const char *ld_debug; /* Environment variable for debugging */ 181 static const char *ld_library_path; /* Environment variable for search path */ 182 static const char *ld_library_dirs; /* Env variable for library descriptors */ 183 static char *ld_preload; /* Environment variable for libraries to 184 load first */ 185 static const char *ld_elf_hints_path; /* Env var. for alternative hints path */ 186 static const char *ld_tracing; /* Called from ldd to print libs */ 187 static const char *ld_utrace; /* Use utrace() to log events. */ 188 static int (*rtld_functrace)( /* Optional function call tracing hook */ 189 const char *caller_obj, 190 const char *callee_obj, 191 const char *callee_func, 192 void *stack); 193 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */ 194 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 195 static Obj_Entry **obj_tail; /* Link field of last object in list */ 196 static Obj_Entry **preload_tail; 197 static Obj_Entry *obj_main; /* The main program shared object */ 198 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 199 static unsigned int obj_count; /* Number of objects in obj_list */ 200 static unsigned int obj_loads; /* Number of objects in obj_list */ 201 202 static int ld_resident; /* Non-zero if resident */ 203 static const char *ld_ary[LD_ARY_CACHE]; 204 static int ld_index; 205 static Objlist initlist; 206 207 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 208 STAILQ_HEAD_INITIALIZER(list_global); 209 static Objlist list_main = /* Objects loaded at program startup */ 210 STAILQ_HEAD_INITIALIZER(list_main); 211 static Objlist list_fini = /* Objects needing fini() calls */ 212 STAILQ_HEAD_INITIALIZER(list_fini); 213 214 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 215 const char *__ld_sharedlib_base; 216 217 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 218 219 extern Elf_Dyn _DYNAMIC; 220 #pragma weak _DYNAMIC 221 #ifndef RTLD_IS_DYNAMIC 222 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 223 #endif 224 225 #ifdef ENABLE_OSRELDATE 226 int osreldate; 227 #endif 228 229 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 230 #if 0 231 static int max_stack_flags; 232 #endif 233 234 /* 235 * Global declarations normally provided by crt1. The dynamic linker is 236 * not built with crt1, so we have to provide them ourselves. 237 */ 238 char *__progname; 239 char **environ; 240 241 /* 242 * Used to pass argc, argv to init functions. 243 */ 244 int main_argc; 245 char **main_argv; 246 247 /* 248 * Globals to control TLS allocation. 249 */ 250 size_t tls_last_offset; /* Static TLS offset of last module */ 251 size_t tls_last_size; /* Static TLS size of last module */ 252 size_t tls_static_space; /* Static TLS space allocated */ 253 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 254 int tls_max_index = 1; /* Largest module index allocated */ 255 256 /* 257 * Fill in a DoneList with an allocation large enough to hold all of 258 * the currently-loaded objects. Keep this as a macro since it calls 259 * alloca and we want that to occur within the scope of the caller. 260 */ 261 #define donelist_init(dlp) \ 262 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 263 assert((dlp)->objs != NULL), \ 264 (dlp)->num_alloc = obj_count, \ 265 (dlp)->num_used = 0) 266 267 #define UTRACE_DLOPEN_START 1 268 #define UTRACE_DLOPEN_STOP 2 269 #define UTRACE_DLCLOSE_START 3 270 #define UTRACE_DLCLOSE_STOP 4 271 #define UTRACE_LOAD_OBJECT 5 272 #define UTRACE_UNLOAD_OBJECT 6 273 #define UTRACE_ADD_RUNDEP 7 274 #define UTRACE_PRELOAD_FINISHED 8 275 #define UTRACE_INIT_CALL 9 276 #define UTRACE_FINI_CALL 10 277 278 struct utrace_rtld { 279 char sig[4]; /* 'RTLD' */ 280 int event; 281 void *handle; 282 void *mapbase; /* Used for 'parent' and 'init/fini' */ 283 size_t mapsize; 284 int refcnt; /* Used for 'mode' */ 285 char name[MAXPATHLEN]; 286 }; 287 288 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 289 if (ld_utrace != NULL) \ 290 ld_utrace_log(e, h, mb, ms, r, n); \ 291 } while (0) 292 293 static void 294 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 295 int refcnt, const char *name) 296 { 297 struct utrace_rtld ut; 298 299 ut.sig[0] = 'R'; 300 ut.sig[1] = 'T'; 301 ut.sig[2] = 'L'; 302 ut.sig[3] = 'D'; 303 ut.event = event; 304 ut.handle = handle; 305 ut.mapbase = mapbase; 306 ut.mapsize = mapsize; 307 ut.refcnt = refcnt; 308 bzero(ut.name, sizeof(ut.name)); 309 if (name) 310 strlcpy(ut.name, name, sizeof(ut.name)); 311 utrace(&ut, sizeof(ut)); 312 } 313 314 /* 315 * Main entry point for dynamic linking. The first argument is the 316 * stack pointer. The stack is expected to be laid out as described 317 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 318 * Specifically, the stack pointer points to a word containing 319 * ARGC. Following that in the stack is a null-terminated sequence 320 * of pointers to argument strings. Then comes a null-terminated 321 * sequence of pointers to environment strings. Finally, there is a 322 * sequence of "auxiliary vector" entries. 323 * 324 * The second argument points to a place to store the dynamic linker's 325 * exit procedure pointer and the third to a place to store the main 326 * program's object. 327 * 328 * The return value is the main program's entry point. 329 */ 330 func_ptr_type 331 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 332 { 333 Elf_Auxinfo *aux_info[AT_COUNT]; 334 int i; 335 int argc; 336 char **argv; 337 char **env; 338 Elf_Auxinfo *aux; 339 Elf_Auxinfo *auxp; 340 const char *argv0; 341 Objlist_Entry *entry; 342 Obj_Entry *obj; 343 Obj_Entry *last_interposer; 344 345 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld 346 Obj_Entry **preload_tail; 347 Objlist initlist; 348 from global to here. It will break the DWARF2 unwind scheme. 349 */ 350 351 /* 352 * On entry, the dynamic linker itself has not been relocated yet. 353 * Be very careful not to reference any global data until after 354 * init_rtld has returned. It is OK to reference file-scope statics 355 * and string constants, and to call static and global functions. 356 */ 357 358 /* Find the auxiliary vector on the stack. */ 359 argc = *sp++; 360 argv = (char **) sp; 361 sp += argc + 1; /* Skip over arguments and NULL terminator */ 362 env = (char **) sp; 363 364 /* 365 * If we aren't already resident we have to dig out some more info. 366 * Note that auxinfo does not exist when we are resident. 367 * 368 * I'm not sure about the ld_resident check. It seems to read zero 369 * prior to relocation, which is what we want. When running from a 370 * resident copy everything will be relocated so we are definitely 371 * good there. 372 */ 373 if (ld_resident == 0) { 374 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 375 ; 376 aux = (Elf_Auxinfo *) sp; 377 378 /* Digest the auxiliary vector. */ 379 for (i = 0; i < AT_COUNT; i++) 380 aux_info[i] = NULL; 381 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 382 if (auxp->a_type < AT_COUNT) 383 aux_info[auxp->a_type] = auxp; 384 } 385 386 /* Initialize and relocate ourselves. */ 387 assert(aux_info[AT_BASE] != NULL); 388 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 389 } 390 391 ld_index = 0; /* don't use old env cache in case we are resident */ 392 __progname = obj_rtld.path; 393 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 394 environ = env; 395 main_argc = argc; 396 main_argv = argv; 397 398 trust = !issetugid(); 399 400 ld_bind_now = _getenv_ld("LD_BIND_NOW"); 401 /* 402 * If the process is tainted, then we un-set the dangerous environment 403 * variables. The process will be marked as tainted until setuid(2) 404 * is called. If any child process calls setuid(2) we do not want any 405 * future processes to honor the potentially un-safe variables. 406 */ 407 if (!trust) { 408 if ( unsetenv("LD_DEBUG") 409 || unsetenv("LD_PRELOAD") 410 || unsetenv("LD_LIBRARY_PATH") 411 || unsetenv("LD_LIBRARY_PATH_FDS") 412 || unsetenv("LD_ELF_HINTS_PATH") 413 || unsetenv("LD_LIBMAP") 414 || unsetenv("LD_LIBMAP_DISABLE") 415 || unsetenv("LD_LOADFLTR") 416 || unsetenv("LD_SHAREDLIB_BASE") 417 ) { 418 _rtld_error("environment corrupt; aborting"); 419 die(); 420 } 421 } 422 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE"); 423 ld_debug = _getenv_ld("LD_DEBUG"); 424 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL; 425 libmap_override = (char *)_getenv_ld("LD_LIBMAP"); 426 ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); 427 ld_library_dirs = _getenv_ld("LD_LIBRARY_PATH_FDS"); 428 ld_preload = (char *)_getenv_ld("LD_PRELOAD"); 429 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH"); 430 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL; 431 dangerous_ld_env = (ld_library_path != NULL) 432 || (ld_preload != NULL) 433 || (ld_elf_hints_path != NULL) 434 || ld_loadfltr 435 || (libmap_override != NULL) 436 || libmap_disable 437 ; 438 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); 439 ld_utrace = _getenv_ld("LD_UTRACE"); 440 441 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 442 ld_elf_hints_path = _PATH_ELF_HINTS; 443 444 if (ld_debug != NULL && *ld_debug != '\0') 445 debug = 1; 446 dbg("%s is initialized, base address = %p", __progname, 447 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 448 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 449 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 450 451 dbg("initializing thread locks"); 452 lockdflt_init(); 453 454 /* 455 * If we are resident we can skip work that we have already done. 456 * Note that the stack is reset and there is no Elf_Auxinfo 457 * when running from a resident image, and the static globals setup 458 * between here and resident_skip will have already been setup. 459 */ 460 if (ld_resident) 461 goto resident_skip1; 462 463 /* 464 * Load the main program, or process its program header if it is 465 * already loaded. 466 */ 467 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 468 int fd = aux_info[AT_EXECFD]->a_un.a_val; 469 dbg("loading main program"); 470 obj_main = map_object(fd, argv0, NULL); 471 close(fd); 472 if (obj_main == NULL) 473 die(); 474 #if 0 475 max_stack_flags = obj_main->stack_flags; 476 #endif 477 } else { /* Main program already loaded. */ 478 const Elf_Phdr *phdr; 479 int phnum; 480 caddr_t entry; 481 482 dbg("processing main program's program header"); 483 assert(aux_info[AT_PHDR] != NULL); 484 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 485 assert(aux_info[AT_PHNUM] != NULL); 486 phnum = aux_info[AT_PHNUM]->a_un.a_val; 487 assert(aux_info[AT_PHENT] != NULL); 488 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 489 assert(aux_info[AT_ENTRY] != NULL); 490 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 491 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 492 die(); 493 } 494 495 char buf[MAXPATHLEN]; 496 if (aux_info[AT_EXECPATH] != NULL) { 497 char *kexecpath; 498 499 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 500 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 501 if (kexecpath[0] == '/') 502 obj_main->path = kexecpath; 503 else if (getcwd(buf, sizeof(buf)) == NULL || 504 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 505 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 506 obj_main->path = xstrdup(argv0); 507 else 508 obj_main->path = xstrdup(buf); 509 } else { 510 char resolved[MAXPATHLEN]; 511 dbg("No AT_EXECPATH"); 512 if (argv0[0] == '/') { 513 if (realpath(argv0, resolved) != NULL) 514 obj_main->path = xstrdup(resolved); 515 else 516 obj_main->path = xstrdup(argv0); 517 } else { 518 if (getcwd(buf, sizeof(buf)) != NULL 519 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf) 520 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf) 521 && access(buf, R_OK) == 0 522 && realpath(buf, resolved) != NULL) 523 obj_main->path = xstrdup(resolved); 524 else 525 obj_main->path = xstrdup(argv0); 526 } 527 } 528 dbg("obj_main path %s", obj_main->path); 529 obj_main->mainprog = true; 530 531 if (aux_info[AT_STACKPROT] != NULL && 532 aux_info[AT_STACKPROT]->a_un.a_val != 0) 533 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 534 535 /* 536 * Get the actual dynamic linker pathname from the executable if 537 * possible. (It should always be possible.) That ensures that 538 * gdb will find the right dynamic linker even if a non-standard 539 * one is being used. 540 */ 541 if (obj_main->interp != NULL && 542 strcmp(obj_main->interp, obj_rtld.path) != 0) { 543 free(obj_rtld.path); 544 obj_rtld.path = xstrdup(obj_main->interp); 545 __progname = obj_rtld.path; 546 } 547 548 digest_dynamic(obj_main, 0); 549 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 550 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 551 obj_main->dynsymcount); 552 553 linkmap_add(obj_main); 554 linkmap_add(&obj_rtld); 555 556 /* Link the main program into the list of objects. */ 557 *obj_tail = obj_main; 558 obj_tail = &obj_main->next; 559 obj_count++; 560 obj_loads++; 561 562 /* Initialize a fake symbol for resolving undefined weak references. */ 563 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 564 sym_zero.st_shndx = SHN_UNDEF; 565 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 566 567 if (!libmap_disable) 568 libmap_disable = (bool)lm_init(libmap_override); 569 570 dbg("loading LD_PRELOAD libraries"); 571 if (load_preload_objects() == -1) 572 die(); 573 preload_tail = obj_tail; 574 575 dbg("loading needed objects"); 576 if (load_needed_objects(obj_main, 0) == -1) 577 die(); 578 579 /* Make a list of all objects loaded at startup. */ 580 last_interposer = obj_main; 581 for (obj = obj_list; obj != NULL; obj = obj->next) { 582 if (obj->z_interpose && obj != obj_main) { 583 objlist_put_after(&list_main, last_interposer, obj); 584 last_interposer = obj; 585 } else { 586 objlist_push_tail(&list_main, obj); 587 } 588 obj->refcount++; 589 } 590 591 dbg("checking for required versions"); 592 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 593 die(); 594 595 resident_skip1: 596 597 if (ld_tracing) { /* We're done */ 598 trace_loaded_objects(obj_main); 599 exit(0); 600 } 601 602 if (ld_resident) /* XXX clean this up! */ 603 goto resident_skip2; 604 605 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) { 606 dump_relocations(obj_main); 607 exit (0); 608 } 609 610 /* setup TLS for main thread */ 611 dbg("initializing initial thread local storage"); 612 STAILQ_FOREACH(entry, &list_main, link) { 613 /* 614 * Allocate all the initial objects out of the static TLS 615 * block even if they didn't ask for it. 616 */ 617 allocate_tls_offset(entry->obj); 618 } 619 620 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 621 622 /* 623 * Do not try to allocate the TLS here, let libc do it itself. 624 * (crt1 for the program will call _init_tls()) 625 */ 626 627 if (relocate_objects(obj_main, 628 ld_bind_now != NULL && *ld_bind_now != '\0', 629 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 630 die(); 631 632 dbg("doing copy relocations"); 633 if (do_copy_relocations(obj_main) == -1) 634 die(); 635 636 resident_skip2: 637 638 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { 639 if (exec_sys_unregister(-1) < 0) { 640 dbg("exec_sys_unregister failed %d\n", errno); 641 exit(errno); 642 } 643 dbg("exec_sys_unregister success\n"); 644 exit(0); 645 } 646 647 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) { 648 dump_relocations(obj_main); 649 exit (0); 650 } 651 652 dbg("initializing key program variables"); 653 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 654 set_program_var("environ", env); 655 set_program_var("__elf_aux_vector", aux); 656 657 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { 658 extern void resident_start(void); 659 ld_resident = 1; 660 if (exec_sys_register(resident_start) < 0) { 661 dbg("exec_sys_register failed %d\n", errno); 662 exit(errno); 663 } 664 dbg("exec_sys_register success\n"); 665 exit(0); 666 } 667 668 /* Make a list of init functions to call. */ 669 objlist_init(&initlist); 670 initlist_add_objects(obj_list, preload_tail, &initlist); 671 672 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 673 674 map_stacks_exec(NULL); 675 676 dbg("resolving ifuncs"); 677 if (resolve_objects_ifunc(obj_main, 678 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 679 NULL) == -1) 680 die(); 681 682 /* 683 * Do NOT call the initlist here, give libc a chance to set up 684 * the initial TLS segment. crt1 will then call _rtld_call_init(). 685 */ 686 687 dbg("transferring control to program entry point = %p", obj_main->entry); 688 689 /* Return the exit procedure and the program entry point. */ 690 *exit_proc = rtld_exit; 691 *objp = obj_main; 692 return (func_ptr_type) obj_main->entry; 693 } 694 695 /* 696 * Call the initialization list for dynamically loaded libraries. 697 * (called from crt1.c). 698 */ 699 void 700 _rtld_call_init(void) 701 { 702 RtldLockState lockstate; 703 Obj_Entry *obj; 704 705 if (!obj_main->note_present && obj_main->valid_hash_gnu) { 706 /* 707 * The use of a linker script with a PHDRS directive that does not include 708 * PT_NOTE will block the crt_no_init note. In this case we'll look for the 709 * recently added GNU hash dynamic tag which gets built by default. It is 710 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and 711 * a gnu hash tag. If gnu hash found, consider binary to use new crt code. 712 */ 713 obj_main->crt_no_init = true; 714 dbg("Setting crt_no_init without presence of PT_NOTE header"); 715 } 716 717 wlock_acquire(rtld_bind_lock, &lockstate); 718 if (obj_main->crt_no_init) 719 preinit_main(); 720 else { 721 /* 722 * Make sure we don't call the main program's init and fini functions 723 * for binaries linked with old crt1 which calls _init itself. 724 */ 725 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 726 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL; 727 } 728 objlist_call_init(&initlist, &lockstate); 729 _r_debug_postinit(&obj_main->linkmap); 730 objlist_clear(&initlist); 731 dbg("loading filtees"); 732 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 733 if (ld_loadfltr || obj->z_loadfltr) 734 load_filtees(obj, 0, &lockstate); 735 } 736 lock_release(rtld_bind_lock, &lockstate); 737 } 738 739 void * 740 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 741 { 742 void *ptr; 743 Elf_Addr target; 744 745 ptr = (void *)make_function_pointer(def, obj); 746 target = ((Elf_Addr (*)(void))ptr)(); 747 return ((void *)target); 748 } 749 750 Elf_Addr 751 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack) 752 { 753 const Elf_Rel *rel; 754 const Elf_Sym *def; 755 const Obj_Entry *defobj; 756 Elf_Addr *where; 757 Elf_Addr target; 758 RtldLockState lockstate; 759 760 rlock_acquire(rtld_bind_lock, &lockstate); 761 if (sigsetjmp(lockstate.env, 0) != 0) 762 lock_upgrade(rtld_bind_lock, &lockstate); 763 if (obj->pltrel) 764 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 765 else 766 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 767 768 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 769 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 770 &lockstate); 771 if (def == NULL) 772 die(); 773 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 774 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 775 else 776 target = (Elf_Addr)(defobj->relocbase + def->st_value); 777 778 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 779 defobj->strtab + def->st_name, basename(obj->path), 780 (void *)target, basename(defobj->path)); 781 782 /* 783 * If we have a function call tracing hook, and the 784 * hook would like to keep tracing this one function, 785 * prevent the relocation so we will wind up here 786 * the next time again. 787 * 788 * We don't want to functrace calls from the functracer 789 * to avoid recursive loops. 790 */ 791 if (rtld_functrace != NULL && obj != rtld_functrace_obj) { 792 if (rtld_functrace(obj->path, 793 defobj->path, 794 defobj->strtab + def->st_name, 795 stack)) { 796 lock_release(rtld_bind_lock, &lockstate); 797 return target; 798 } 799 } 800 801 /* 802 * Write the new contents for the jmpslot. Note that depending on 803 * architecture, the value which we need to return back to the 804 * lazy binding trampoline may or may not be the target 805 * address. The value returned from reloc_jmpslot() is the value 806 * that the trampoline needs. 807 */ 808 target = reloc_jmpslot(where, target, defobj, obj, rel); 809 lock_release(rtld_bind_lock, &lockstate); 810 return target; 811 } 812 813 /* 814 * Error reporting function. Use it like printf. If formats the message 815 * into a buffer, and sets things up so that the next call to dlerror() 816 * will return the message. 817 */ 818 void 819 _rtld_error(const char *fmt, ...) 820 { 821 static char buf[512]; 822 va_list ap; 823 824 va_start(ap, fmt); 825 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 826 error_message = buf; 827 va_end(ap); 828 } 829 830 /* 831 * Return a dynamically-allocated copy of the current error message, if any. 832 */ 833 static char * 834 errmsg_save(void) 835 { 836 return error_message == NULL ? NULL : xstrdup(error_message); 837 } 838 839 /* 840 * Restore the current error message from a copy which was previously saved 841 * by errmsg_save(). The copy is freed. 842 */ 843 static void 844 errmsg_restore(char *saved_msg) 845 { 846 if (saved_msg == NULL) 847 error_message = NULL; 848 else { 849 _rtld_error("%s", saved_msg); 850 free(saved_msg); 851 } 852 } 853 854 const char * 855 basename(const char *name) 856 { 857 const char *p = strrchr(name, '/'); 858 return p != NULL ? p + 1 : name; 859 } 860 861 static struct utsname uts; 862 863 static char * 864 origin_subst_one(char *real, const char *kw, const char *subst, 865 bool may_free) 866 { 867 char *p, *p1, *res, *resp; 868 int subst_len, kw_len, subst_count, old_len, new_len; 869 870 kw_len = strlen(kw); 871 872 /* 873 * First, count the number of the keyword occurrences, to 874 * preallocate the final string. 875 */ 876 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 877 p1 = strstr(p, kw); 878 if (p1 == NULL) 879 break; 880 } 881 882 /* 883 * If the keyword is not found, just return. 884 */ 885 if (subst_count == 0) 886 return (may_free ? real : xstrdup(real)); 887 888 /* 889 * There is indeed something to substitute. Calculate the 890 * length of the resulting string, and allocate it. 891 */ 892 subst_len = strlen(subst); 893 old_len = strlen(real); 894 new_len = old_len + (subst_len - kw_len) * subst_count; 895 res = xmalloc(new_len + 1); 896 897 /* 898 * Now, execute the substitution loop. 899 */ 900 for (p = real, resp = res, *resp = '\0';;) { 901 p1 = strstr(p, kw); 902 if (p1 != NULL) { 903 /* Copy the prefix before keyword. */ 904 memcpy(resp, p, p1 - p); 905 resp += p1 - p; 906 /* Keyword replacement. */ 907 memcpy(resp, subst, subst_len); 908 resp += subst_len; 909 *resp = '\0'; 910 p = p1 + kw_len; 911 } else 912 break; 913 } 914 915 /* Copy to the end of string and finish. */ 916 strcat(resp, p); 917 if (may_free) 918 free(real); 919 return (res); 920 } 921 922 static char * 923 origin_subst(char *real, const char *origin_path) 924 { 925 char *res1, *res2, *res3, *res4; 926 927 if (uts.sysname[0] == '\0') { 928 if (uname(&uts) != 0) { 929 _rtld_error("utsname failed: %d", errno); 930 return (NULL); 931 } 932 } 933 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false); 934 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true); 935 res3 = origin_subst_one(res2, "$OSREL", uts.release, true); 936 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true); 937 return (res4); 938 } 939 940 static void 941 die(void) 942 { 943 const char *msg = dlerror(); 944 945 if (msg == NULL) 946 msg = "Fatal error"; 947 rtld_fdputstr(STDERR_FILENO, msg); 948 rtld_fdputchar(STDERR_FILENO, '\n'); 949 _exit(1); 950 } 951 952 /* 953 * Process a shared object's DYNAMIC section, and save the important 954 * information in its Obj_Entry structure. 955 */ 956 static void 957 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 958 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 959 { 960 const Elf_Dyn *dynp; 961 Needed_Entry **needed_tail = &obj->needed; 962 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 963 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 964 const Elf_Hashelt *hashtab; 965 const Elf32_Word *hashval; 966 Elf32_Word bkt, nmaskwords; 967 int bloom_size32; 968 bool nmw_power2; 969 int plttype = DT_REL; 970 971 *dyn_rpath = NULL; 972 *dyn_soname = NULL; 973 *dyn_runpath = NULL; 974 975 obj->bind_now = false; 976 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 977 switch (dynp->d_tag) { 978 979 case DT_REL: 980 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 981 break; 982 983 case DT_RELSZ: 984 obj->relsize = dynp->d_un.d_val; 985 break; 986 987 case DT_RELENT: 988 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 989 break; 990 991 case DT_JMPREL: 992 obj->pltrel = (const Elf_Rel *) 993 (obj->relocbase + dynp->d_un.d_ptr); 994 break; 995 996 case DT_PLTRELSZ: 997 obj->pltrelsize = dynp->d_un.d_val; 998 break; 999 1000 case DT_RELA: 1001 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 1002 break; 1003 1004 case DT_RELASZ: 1005 obj->relasize = dynp->d_un.d_val; 1006 break; 1007 1008 case DT_RELAENT: 1009 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 1010 break; 1011 1012 case DT_PLTREL: 1013 plttype = dynp->d_un.d_val; 1014 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 1015 break; 1016 1017 case DT_SYMTAB: 1018 obj->symtab = (const Elf_Sym *) 1019 (obj->relocbase + dynp->d_un.d_ptr); 1020 break; 1021 1022 case DT_SYMENT: 1023 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 1024 break; 1025 1026 case DT_STRTAB: 1027 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 1028 break; 1029 1030 case DT_STRSZ: 1031 obj->strsize = dynp->d_un.d_val; 1032 break; 1033 1034 case DT_VERNEED: 1035 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 1036 dynp->d_un.d_val); 1037 break; 1038 1039 case DT_VERNEEDNUM: 1040 obj->verneednum = dynp->d_un.d_val; 1041 break; 1042 1043 case DT_VERDEF: 1044 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 1045 dynp->d_un.d_val); 1046 break; 1047 1048 case DT_VERDEFNUM: 1049 obj->verdefnum = dynp->d_un.d_val; 1050 break; 1051 1052 case DT_VERSYM: 1053 obj->versyms = (const Elf_Versym *)(obj->relocbase + 1054 dynp->d_un.d_val); 1055 break; 1056 1057 case DT_HASH: 1058 { 1059 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1060 dynp->d_un.d_ptr); 1061 obj->nbuckets = hashtab[0]; 1062 obj->nchains = hashtab[1]; 1063 obj->buckets = hashtab + 2; 1064 obj->chains = obj->buckets + obj->nbuckets; 1065 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1066 obj->buckets != NULL; 1067 } 1068 break; 1069 1070 case DT_GNU_HASH: 1071 { 1072 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1073 dynp->d_un.d_ptr); 1074 obj->nbuckets_gnu = hashtab[0]; 1075 obj->symndx_gnu = hashtab[1]; 1076 nmaskwords = hashtab[2]; 1077 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1078 /* Number of bitmask words is required to be power of 2 */ 1079 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0); 1080 obj->maskwords_bm_gnu = nmaskwords - 1; 1081 obj->shift2_gnu = hashtab[3]; 1082 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1083 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1084 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1085 obj->symndx_gnu; 1086 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 && 1087 obj->buckets_gnu != NULL; 1088 } 1089 break; 1090 1091 case DT_NEEDED: 1092 if (!obj->rtld) { 1093 Needed_Entry *nep = NEW(Needed_Entry); 1094 nep->name = dynp->d_un.d_val; 1095 nep->obj = NULL; 1096 nep->next = NULL; 1097 1098 *needed_tail = nep; 1099 needed_tail = &nep->next; 1100 } 1101 break; 1102 1103 case DT_FILTER: 1104 if (!obj->rtld) { 1105 Needed_Entry *nep = NEW(Needed_Entry); 1106 nep->name = dynp->d_un.d_val; 1107 nep->obj = NULL; 1108 nep->next = NULL; 1109 1110 *needed_filtees_tail = nep; 1111 needed_filtees_tail = &nep->next; 1112 } 1113 break; 1114 1115 case DT_AUXILIARY: 1116 if (!obj->rtld) { 1117 Needed_Entry *nep = NEW(Needed_Entry); 1118 nep->name = dynp->d_un.d_val; 1119 nep->obj = NULL; 1120 nep->next = NULL; 1121 1122 *needed_aux_filtees_tail = nep; 1123 needed_aux_filtees_tail = &nep->next; 1124 } 1125 break; 1126 1127 case DT_PLTGOT: 1128 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1129 break; 1130 1131 case DT_TEXTREL: 1132 obj->textrel = true; 1133 break; 1134 1135 case DT_SYMBOLIC: 1136 obj->symbolic = true; 1137 break; 1138 1139 case DT_RPATH: 1140 /* 1141 * We have to wait until later to process this, because we 1142 * might not have gotten the address of the string table yet. 1143 */ 1144 *dyn_rpath = dynp; 1145 break; 1146 1147 case DT_SONAME: 1148 *dyn_soname = dynp; 1149 break; 1150 1151 case DT_RUNPATH: 1152 *dyn_runpath = dynp; 1153 break; 1154 1155 case DT_INIT: 1156 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1157 break; 1158 1159 case DT_PREINIT_ARRAY: 1160 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1161 break; 1162 1163 case DT_PREINIT_ARRAYSZ: 1164 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1165 break; 1166 1167 case DT_INIT_ARRAY: 1168 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1169 break; 1170 1171 case DT_INIT_ARRAYSZ: 1172 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1173 break; 1174 1175 case DT_FINI: 1176 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1177 break; 1178 1179 case DT_FINI_ARRAY: 1180 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1181 break; 1182 1183 case DT_FINI_ARRAYSZ: 1184 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1185 break; 1186 1187 case DT_DEBUG: 1188 /* XXX - not implemented yet */ 1189 if (!early) 1190 dbg("Filling in DT_DEBUG entry"); 1191 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1192 break; 1193 1194 case DT_FLAGS: 1195 if ((dynp->d_un.d_val & DF_ORIGIN) && trust) 1196 obj->z_origin = true; 1197 if (dynp->d_un.d_val & DF_SYMBOLIC) 1198 obj->symbolic = true; 1199 if (dynp->d_un.d_val & DF_TEXTREL) 1200 obj->textrel = true; 1201 if (dynp->d_un.d_val & DF_BIND_NOW) 1202 obj->bind_now = true; 1203 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1204 ;*/ 1205 break; 1206 1207 case DT_FLAGS_1: 1208 if (dynp->d_un.d_val & DF_1_NOOPEN) 1209 obj->z_noopen = true; 1210 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust) 1211 obj->z_origin = true; 1212 /*if (dynp->d_un.d_val & DF_1_GLOBAL) 1213 XXX ;*/ 1214 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1215 obj->bind_now = true; 1216 if (dynp->d_un.d_val & DF_1_NODELETE) 1217 obj->z_nodelete = true; 1218 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1219 obj->z_loadfltr = true; 1220 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1221 obj->z_interpose = true; 1222 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1223 obj->z_nodeflib = true; 1224 break; 1225 1226 default: 1227 if (!early) { 1228 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1229 (long)dynp->d_tag); 1230 } 1231 break; 1232 } 1233 } 1234 1235 obj->traced = false; 1236 1237 if (plttype == DT_RELA) { 1238 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1239 obj->pltrel = NULL; 1240 obj->pltrelasize = obj->pltrelsize; 1241 obj->pltrelsize = 0; 1242 } 1243 1244 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1245 if (obj->valid_hash_sysv) 1246 obj->dynsymcount = obj->nchains; 1247 else if (obj->valid_hash_gnu) { 1248 obj->dynsymcount = 0; 1249 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1250 if (obj->buckets_gnu[bkt] == 0) 1251 continue; 1252 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1253 do 1254 obj->dynsymcount++; 1255 while ((*hashval++ & 1u) == 0); 1256 } 1257 obj->dynsymcount += obj->symndx_gnu; 1258 } 1259 } 1260 1261 static void 1262 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1263 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1264 { 1265 1266 if (obj->z_origin && obj->origin_path == NULL) { 1267 obj->origin_path = xmalloc(PATH_MAX); 1268 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1) 1269 die(); 1270 } 1271 1272 if (dyn_runpath != NULL) { 1273 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1274 if (obj->z_origin) 1275 obj->runpath = origin_subst(obj->runpath, obj->origin_path); 1276 } 1277 else if (dyn_rpath != NULL) { 1278 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1279 if (obj->z_origin) 1280 obj->rpath = origin_subst(obj->rpath, obj->origin_path); 1281 } 1282 1283 if (dyn_soname != NULL) 1284 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1285 } 1286 1287 static void 1288 digest_dynamic(Obj_Entry *obj, int early) 1289 { 1290 const Elf_Dyn *dyn_rpath; 1291 const Elf_Dyn *dyn_soname; 1292 const Elf_Dyn *dyn_runpath; 1293 1294 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1295 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1296 } 1297 1298 /* 1299 * Process a shared object's program header. This is used only for the 1300 * main program, when the kernel has already loaded the main program 1301 * into memory before calling the dynamic linker. It creates and 1302 * returns an Obj_Entry structure. 1303 */ 1304 static Obj_Entry * 1305 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1306 { 1307 Obj_Entry *obj; 1308 const Elf_Phdr *phlimit = phdr + phnum; 1309 const Elf_Phdr *ph; 1310 Elf_Addr note_start, note_end; 1311 int nsegs = 0; 1312 1313 obj = obj_new(); 1314 for (ph = phdr; ph < phlimit; ph++) { 1315 if (ph->p_type != PT_PHDR) 1316 continue; 1317 1318 obj->phdr = phdr; 1319 obj->phsize = ph->p_memsz; 1320 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1321 break; 1322 } 1323 1324 obj->stack_flags = PF_X | PF_R | PF_W; 1325 1326 for (ph = phdr; ph < phlimit; ph++) { 1327 switch (ph->p_type) { 1328 1329 case PT_INTERP: 1330 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1331 break; 1332 1333 case PT_LOAD: 1334 if (nsegs == 0) { /* First load segment */ 1335 obj->vaddrbase = trunc_page(ph->p_vaddr); 1336 obj->mapbase = obj->vaddrbase + obj->relocbase; 1337 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1338 obj->vaddrbase; 1339 } else { /* Last load segment */ 1340 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1341 obj->vaddrbase; 1342 } 1343 nsegs++; 1344 break; 1345 1346 case PT_DYNAMIC: 1347 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1348 break; 1349 1350 case PT_TLS: 1351 obj->tlsindex = 1; 1352 obj->tlssize = ph->p_memsz; 1353 obj->tlsalign = ph->p_align; 1354 obj->tlsinitsize = ph->p_filesz; 1355 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1356 break; 1357 1358 case PT_GNU_STACK: 1359 obj->stack_flags = ph->p_flags; 1360 break; 1361 1362 case PT_GNU_RELRO: 1363 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1364 obj->relro_size = round_page(ph->p_memsz); 1365 break; 1366 1367 case PT_NOTE: 1368 obj->note_present = true; 1369 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1370 note_end = note_start + ph->p_filesz; 1371 digest_notes(obj, note_start, note_end); 1372 break; 1373 } 1374 } 1375 if (nsegs < 1) { 1376 _rtld_error("%s: too few PT_LOAD segments", path); 1377 return NULL; 1378 } 1379 1380 obj->entry = entry; 1381 return obj; 1382 } 1383 1384 void 1385 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1386 { 1387 const Elf_Note *note; 1388 const char *note_name; 1389 uintptr_t p; 1390 1391 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1392 note = (const Elf_Note *)((const char *)(note + 1) + 1393 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1394 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1395 if (note->n_namesz != sizeof(NOTE_VENDOR) || 1396 note->n_descsz != sizeof(int32_t)) 1397 continue; 1398 if (note->n_type != ABI_NOTETYPE && 1399 note->n_type != CRT_NOINIT_NOTETYPE) 1400 continue; 1401 note_name = (const char *)(note + 1); 1402 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0) 1403 continue; 1404 switch (note->n_type) { 1405 case ABI_NOTETYPE: 1406 /* DragonFly osrel note */ 1407 p = (uintptr_t)(note + 1); 1408 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1409 obj->osrel = *(const int32_t *)(p); 1410 dbg("note osrel %d", obj->osrel); 1411 break; 1412 case CRT_NOINIT_NOTETYPE: 1413 /* DragonFly 'crt does not call init' note */ 1414 obj->crt_no_init = true; 1415 dbg("note crt_no_init"); 1416 break; 1417 } 1418 } 1419 } 1420 1421 static Obj_Entry * 1422 dlcheck(void *handle) 1423 { 1424 Obj_Entry *obj; 1425 1426 for (obj = obj_list; obj != NULL; obj = obj->next) 1427 if (obj == (Obj_Entry *) handle) 1428 break; 1429 1430 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1431 _rtld_error("Invalid shared object handle %p", handle); 1432 return NULL; 1433 } 1434 return obj; 1435 } 1436 1437 /* 1438 * If the given object is already in the donelist, return true. Otherwise 1439 * add the object to the list and return false. 1440 */ 1441 static bool 1442 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1443 { 1444 unsigned int i; 1445 1446 for (i = 0; i < dlp->num_used; i++) 1447 if (dlp->objs[i] == obj) 1448 return true; 1449 /* 1450 * Our donelist allocation should always be sufficient. But if 1451 * our threads locking isn't working properly, more shared objects 1452 * could have been loaded since we allocated the list. That should 1453 * never happen, but we'll handle it properly just in case it does. 1454 */ 1455 if (dlp->num_used < dlp->num_alloc) 1456 dlp->objs[dlp->num_used++] = obj; 1457 return false; 1458 } 1459 1460 /* 1461 * Hash function for symbol table lookup. Don't even think about changing 1462 * this. It is specified by the System V ABI. 1463 */ 1464 unsigned long 1465 elf_hash(const char *name) 1466 { 1467 const unsigned char *p = (const unsigned char *) name; 1468 unsigned long h = 0; 1469 unsigned long g; 1470 1471 while (*p != '\0') { 1472 h = (h << 4) + *p++; 1473 if ((g = h & 0xf0000000) != 0) 1474 h ^= g >> 24; 1475 h &= ~g; 1476 } 1477 return h; 1478 } 1479 1480 /* 1481 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1482 * unsigned in case it's implemented with a wider type. 1483 */ 1484 static uint_fast32_t 1485 gnu_hash(const char *s) 1486 { 1487 uint_fast32_t h; 1488 unsigned char c; 1489 1490 h = 5381; 1491 for (c = *s; c != '\0'; c = *++s) 1492 h = h * 33 + c; 1493 return (h & 0xffffffff); 1494 } 1495 1496 1497 /* 1498 * Find the library with the given name, and return its full pathname. 1499 * The returned string is dynamically allocated. Generates an error 1500 * message and returns NULL if the library cannot be found. 1501 * 1502 * If the second argument is non-NULL, then it refers to an already- 1503 * loaded shared object, whose library search path will be searched. 1504 * 1505 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1506 * descriptor (which is close-on-exec) will be passed out via the third 1507 * argument. 1508 * 1509 * The search order is: 1510 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1511 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1512 * LD_LIBRARY_PATH 1513 * DT_RUNPATH in the referencing file 1514 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1515 * from list) 1516 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1517 * 1518 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1519 */ 1520 static char * 1521 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1522 { 1523 char *pathname; 1524 char *name; 1525 bool nodeflib, objgiven; 1526 1527 objgiven = refobj != NULL; 1528 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1529 if (xname[0] != '/' && !trust) { 1530 _rtld_error("Absolute pathname required for shared object \"%s\"", 1531 xname); 1532 return NULL; 1533 } 1534 if (objgiven && refobj->z_origin) { 1535 return (origin_subst(__DECONST(char *, xname), 1536 refobj->origin_path)); 1537 } else { 1538 return (xstrdup(xname)); 1539 } 1540 } 1541 1542 if (libmap_disable || !objgiven || 1543 (name = lm_find(refobj->path, xname)) == NULL) 1544 name = (char *)xname; 1545 1546 dbg(" Searching for \"%s\"", name); 1547 1548 nodeflib = objgiven ? refobj->z_nodeflib : false; 1549 if ((objgiven && 1550 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1551 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1552 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1553 (pathname = search_library_path(name, ld_library_path)) != NULL || 1554 (objgiven && 1555 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1556 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1557 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1558 (objgiven && !nodeflib && 1559 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1560 return (pathname); 1561 1562 if (objgiven && refobj->path != NULL) { 1563 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1564 name, basename(refobj->path)); 1565 } else { 1566 _rtld_error("Shared object \"%s\" not found", name); 1567 } 1568 return NULL; 1569 } 1570 1571 /* 1572 * Given a symbol number in a referencing object, find the corresponding 1573 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1574 * no definition was found. Returns a pointer to the Obj_Entry of the 1575 * defining object via the reference parameter DEFOBJ_OUT. 1576 */ 1577 const Elf_Sym * 1578 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1579 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1580 RtldLockState *lockstate) 1581 { 1582 const Elf_Sym *ref; 1583 const Elf_Sym *def; 1584 const Obj_Entry *defobj; 1585 SymLook req; 1586 const char *name; 1587 int res; 1588 1589 /* 1590 * If we have already found this symbol, get the information from 1591 * the cache. 1592 */ 1593 if (symnum >= refobj->dynsymcount) 1594 return NULL; /* Bad object */ 1595 if (cache != NULL && cache[symnum].sym != NULL) { 1596 *defobj_out = cache[symnum].obj; 1597 return cache[symnum].sym; 1598 } 1599 1600 ref = refobj->symtab + symnum; 1601 name = refobj->strtab + ref->st_name; 1602 def = NULL; 1603 defobj = NULL; 1604 1605 /* 1606 * We don't have to do a full scale lookup if the symbol is local. 1607 * We know it will bind to the instance in this load module; to 1608 * which we already have a pointer (ie ref). By not doing a lookup, 1609 * we not only improve performance, but it also avoids unresolvable 1610 * symbols when local symbols are not in the hash table. 1611 * 1612 * This might occur for TLS module relocations, which simply use 1613 * symbol 0. 1614 */ 1615 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1616 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1617 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1618 symnum); 1619 } 1620 symlook_init(&req, name); 1621 req.flags = flags; 1622 req.ventry = fetch_ventry(refobj, symnum); 1623 req.lockstate = lockstate; 1624 res = symlook_default(&req, refobj); 1625 if (res == 0) { 1626 def = req.sym_out; 1627 defobj = req.defobj_out; 1628 } 1629 } else { 1630 def = ref; 1631 defobj = refobj; 1632 } 1633 1634 /* 1635 * If we found no definition and the reference is weak, treat the 1636 * symbol as having the value zero. 1637 */ 1638 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1639 def = &sym_zero; 1640 defobj = obj_main; 1641 } 1642 1643 if (def != NULL) { 1644 *defobj_out = defobj; 1645 /* Record the information in the cache to avoid subsequent lookups. */ 1646 if (cache != NULL) { 1647 cache[symnum].sym = def; 1648 cache[symnum].obj = defobj; 1649 } 1650 } else { 1651 if (refobj != &obj_rtld) 1652 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1653 } 1654 return def; 1655 } 1656 1657 /* 1658 * Return the search path from the ldconfig hints file, reading it if 1659 * necessary. If nostdlib is true, then the default search paths are 1660 * not added to result. 1661 * 1662 * Returns NULL if there are problems with the hints file, 1663 * or if the search path there is empty. 1664 */ 1665 static const char * 1666 gethints(bool nostdlib) 1667 { 1668 static char *hints, *filtered_path; 1669 struct elfhints_hdr hdr; 1670 struct fill_search_info_args sargs, hargs; 1671 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1672 struct dl_serpath *SLPpath, *hintpath; 1673 char *p; 1674 unsigned int SLPndx, hintndx, fndx, fcount; 1675 int fd; 1676 size_t flen; 1677 bool skip; 1678 1679 /* First call, read the hints file */ 1680 if (hints == NULL) { 1681 /* Keep from trying again in case the hints file is bad. */ 1682 hints = ""; 1683 1684 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1685 return (NULL); 1686 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1687 hdr.magic != ELFHINTS_MAGIC || 1688 hdr.version != 1) { 1689 close(fd); 1690 return (NULL); 1691 } 1692 p = xmalloc(hdr.dirlistlen + 1); 1693 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1694 read(fd, p, hdr.dirlistlen + 1) != 1695 (ssize_t)hdr.dirlistlen + 1) { 1696 free(p); 1697 close(fd); 1698 return (NULL); 1699 } 1700 hints = p; 1701 close(fd); 1702 } 1703 1704 /* 1705 * If caller agreed to receive list which includes the default 1706 * paths, we are done. Otherwise, if we still have not 1707 * calculated filtered result, do it now. 1708 */ 1709 if (!nostdlib) 1710 return (hints[0] != '\0' ? hints : NULL); 1711 if (filtered_path != NULL) 1712 goto filt_ret; 1713 1714 /* 1715 * Obtain the list of all configured search paths, and the 1716 * list of the default paths. 1717 * 1718 * First estimate the size of the results. 1719 */ 1720 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1721 smeta.dls_cnt = 0; 1722 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1723 hmeta.dls_cnt = 0; 1724 1725 sargs.request = RTLD_DI_SERINFOSIZE; 1726 sargs.serinfo = &smeta; 1727 hargs.request = RTLD_DI_SERINFOSIZE; 1728 hargs.serinfo = &hmeta; 1729 1730 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1731 path_enumerate(p, fill_search_info, &hargs); 1732 1733 SLPinfo = xmalloc(smeta.dls_size); 1734 hintinfo = xmalloc(hmeta.dls_size); 1735 1736 /* 1737 * Next fetch both sets of paths. 1738 */ 1739 sargs.request = RTLD_DI_SERINFO; 1740 sargs.serinfo = SLPinfo; 1741 sargs.serpath = &SLPinfo->dls_serpath[0]; 1742 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1743 1744 hargs.request = RTLD_DI_SERINFO; 1745 hargs.serinfo = hintinfo; 1746 hargs.serpath = &hintinfo->dls_serpath[0]; 1747 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1748 1749 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1750 path_enumerate(p, fill_search_info, &hargs); 1751 1752 /* 1753 * Now calculate the difference between two sets, by excluding 1754 * standard paths from the full set. 1755 */ 1756 fndx = 0; 1757 fcount = 0; 1758 filtered_path = xmalloc(hdr.dirlistlen + 1); 1759 hintpath = &hintinfo->dls_serpath[0]; 1760 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1761 skip = false; 1762 SLPpath = &SLPinfo->dls_serpath[0]; 1763 /* 1764 * Check each standard path against current. 1765 */ 1766 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1767 /* matched, skip the path */ 1768 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1769 skip = true; 1770 break; 1771 } 1772 } 1773 if (skip) 1774 continue; 1775 /* 1776 * Not matched against any standard path, add the path 1777 * to result. Separate consecutive paths with ':'. 1778 */ 1779 if (fcount > 0) { 1780 filtered_path[fndx] = ':'; 1781 fndx++; 1782 } 1783 fcount++; 1784 flen = strlen(hintpath->dls_name); 1785 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1786 fndx += flen; 1787 } 1788 filtered_path[fndx] = '\0'; 1789 1790 free(SLPinfo); 1791 free(hintinfo); 1792 1793 filt_ret: 1794 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1795 } 1796 1797 static void 1798 init_dag(Obj_Entry *root) 1799 { 1800 const Needed_Entry *needed; 1801 const Objlist_Entry *elm; 1802 DoneList donelist; 1803 1804 if (root->dag_inited) 1805 return; 1806 donelist_init(&donelist); 1807 1808 /* Root object belongs to own DAG. */ 1809 objlist_push_tail(&root->dldags, root); 1810 objlist_push_tail(&root->dagmembers, root); 1811 donelist_check(&donelist, root); 1812 1813 /* 1814 * Add dependencies of root object to DAG in breadth order 1815 * by exploiting the fact that each new object get added 1816 * to the tail of the dagmembers list. 1817 */ 1818 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1819 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1820 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1821 continue; 1822 objlist_push_tail(&needed->obj->dldags, root); 1823 objlist_push_tail(&root->dagmembers, needed->obj); 1824 } 1825 } 1826 root->dag_inited = true; 1827 } 1828 1829 static void 1830 process_nodelete(Obj_Entry *root) 1831 { 1832 const Objlist_Entry *elm; 1833 1834 /* 1835 * Walk over object DAG and process every dependent object that 1836 * is marked as DF_1_NODELETE. They need to grow their own DAG, 1837 * which then should have its reference upped separately. 1838 */ 1839 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1840 if (elm->obj != NULL && elm->obj->z_nodelete && 1841 !elm->obj->ref_nodel) { 1842 dbg("obj %s nodelete", elm->obj->path); 1843 init_dag(elm->obj); 1844 ref_dag(elm->obj); 1845 elm->obj->ref_nodel = true; 1846 } 1847 } 1848 } 1849 1850 /* 1851 * Initialize the dynamic linker. The argument is the address at which 1852 * the dynamic linker has been mapped into memory. The primary task of 1853 * this function is to relocate the dynamic linker. 1854 */ 1855 static void 1856 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1857 { 1858 Obj_Entry objtmp; /* Temporary rtld object */ 1859 const Elf_Ehdr *ehdr; 1860 const Elf_Dyn *dyn_rpath; 1861 const Elf_Dyn *dyn_soname; 1862 const Elf_Dyn *dyn_runpath; 1863 1864 /* 1865 * Conjure up an Obj_Entry structure for the dynamic linker. 1866 * 1867 * The "path" member can't be initialized yet because string constants 1868 * cannot yet be accessed. Below we will set it correctly. 1869 */ 1870 memset(&objtmp, 0, sizeof(objtmp)); 1871 objtmp.path = NULL; 1872 objtmp.rtld = true; 1873 objtmp.mapbase = mapbase; 1874 #ifdef PIC 1875 objtmp.relocbase = mapbase; 1876 #endif 1877 if (RTLD_IS_DYNAMIC()) { 1878 objtmp.dynamic = rtld_dynamic(&objtmp); 1879 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1880 assert(objtmp.needed == NULL); 1881 assert(!objtmp.textrel); 1882 1883 /* 1884 * Temporarily put the dynamic linker entry into the object list, so 1885 * that symbols can be found. 1886 */ 1887 1888 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1889 } 1890 ehdr = (Elf_Ehdr *)mapbase; 1891 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); 1892 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]); 1893 1894 /* Initialize the object list. */ 1895 obj_tail = &obj_list; 1896 1897 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1898 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1899 1900 #ifdef ENABLE_OSRELDATE 1901 if (aux_info[AT_OSRELDATE] != NULL) 1902 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1903 #endif 1904 1905 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1906 1907 /* Replace the path with a dynamically allocated copy. */ 1908 obj_rtld.path = xstrdup(PATH_RTLD); 1909 1910 r_debug.r_brk = r_debug_state; 1911 r_debug.r_state = RT_CONSISTENT; 1912 } 1913 1914 /* 1915 * Add the init functions from a needed object list (and its recursive 1916 * needed objects) to "list". This is not used directly; it is a helper 1917 * function for initlist_add_objects(). The write lock must be held 1918 * when this function is called. 1919 */ 1920 static void 1921 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1922 { 1923 /* Recursively process the successor needed objects. */ 1924 if (needed->next != NULL) 1925 initlist_add_neededs(needed->next, list); 1926 1927 /* Process the current needed object. */ 1928 if (needed->obj != NULL) 1929 initlist_add_objects(needed->obj, &needed->obj->next, list); 1930 } 1931 1932 /* 1933 * Scan all of the DAGs rooted in the range of objects from "obj" to 1934 * "tail" and add their init functions to "list". This recurses over 1935 * the DAGs and ensure the proper init ordering such that each object's 1936 * needed libraries are initialized before the object itself. At the 1937 * same time, this function adds the objects to the global finalization 1938 * list "list_fini" in the opposite order. The write lock must be 1939 * held when this function is called. 1940 */ 1941 static void 1942 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1943 { 1944 1945 if (obj->init_scanned || obj->init_done) 1946 return; 1947 obj->init_scanned = true; 1948 1949 /* Recursively process the successor objects. */ 1950 if (&obj->next != tail) 1951 initlist_add_objects(obj->next, tail, list); 1952 1953 /* Recursively process the needed objects. */ 1954 if (obj->needed != NULL) 1955 initlist_add_neededs(obj->needed, list); 1956 if (obj->needed_filtees != NULL) 1957 initlist_add_neededs(obj->needed_filtees, list); 1958 if (obj->needed_aux_filtees != NULL) 1959 initlist_add_neededs(obj->needed_aux_filtees, list); 1960 1961 /* Add the object to the init list. */ 1962 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1963 obj->init_array != (Elf_Addr)NULL) 1964 objlist_push_tail(list, obj); 1965 1966 /* Add the object to the global fini list in the reverse order. */ 1967 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1968 && !obj->on_fini_list) { 1969 objlist_push_head(&list_fini, obj); 1970 obj->on_fini_list = true; 1971 } 1972 } 1973 1974 #ifndef FPTR_TARGET 1975 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 1976 #endif 1977 1978 static void 1979 free_needed_filtees(Needed_Entry *n) 1980 { 1981 Needed_Entry *needed, *needed1; 1982 1983 for (needed = n; needed != NULL; needed = needed->next) { 1984 if (needed->obj != NULL) { 1985 dlclose(needed->obj); 1986 needed->obj = NULL; 1987 } 1988 } 1989 for (needed = n; needed != NULL; needed = needed1) { 1990 needed1 = needed->next; 1991 free(needed); 1992 } 1993 } 1994 1995 static void 1996 unload_filtees(Obj_Entry *obj) 1997 { 1998 1999 free_needed_filtees(obj->needed_filtees); 2000 obj->needed_filtees = NULL; 2001 free_needed_filtees(obj->needed_aux_filtees); 2002 obj->needed_aux_filtees = NULL; 2003 obj->filtees_loaded = false; 2004 } 2005 2006 static void 2007 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2008 RtldLockState *lockstate) 2009 { 2010 2011 for (; needed != NULL; needed = needed->next) { 2012 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2013 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2014 RTLD_LOCAL, lockstate); 2015 } 2016 } 2017 2018 static void 2019 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2020 { 2021 2022 lock_restart_for_upgrade(lockstate); 2023 if (!obj->filtees_loaded) { 2024 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2025 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2026 obj->filtees_loaded = true; 2027 } 2028 } 2029 2030 static int 2031 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2032 { 2033 Obj_Entry *obj1; 2034 2035 for (; needed != NULL; needed = needed->next) { 2036 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2037 flags & ~RTLD_LO_NOLOAD); 2038 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2039 return (-1); 2040 } 2041 return (0); 2042 } 2043 2044 /* 2045 * Given a shared object, traverse its list of needed objects, and load 2046 * each of them. Returns 0 on success. Generates an error message and 2047 * returns -1 on failure. 2048 */ 2049 static int 2050 load_needed_objects(Obj_Entry *first, int flags) 2051 { 2052 Obj_Entry *obj; 2053 2054 for (obj = first; obj != NULL; obj = obj->next) { 2055 if (process_needed(obj, obj->needed, flags) == -1) 2056 return (-1); 2057 } 2058 return (0); 2059 } 2060 2061 static int 2062 load_preload_objects(void) 2063 { 2064 char *p = ld_preload; 2065 Obj_Entry *obj; 2066 static const char delim[] = " \t:;"; 2067 2068 if (p == NULL) 2069 return 0; 2070 2071 p += strspn(p, delim); 2072 while (*p != '\0') { 2073 size_t len = strcspn(p, delim); 2074 char savech; 2075 SymLook req; 2076 int res; 2077 2078 savech = p[len]; 2079 p[len] = '\0'; 2080 obj = load_object(p, -1, NULL, 0); 2081 if (obj == NULL) 2082 return -1; /* XXX - cleanup */ 2083 obj->z_interpose = true; 2084 p[len] = savech; 2085 p += len; 2086 p += strspn(p, delim); 2087 2088 /* Check for the magic tracing function */ 2089 symlook_init(&req, RTLD_FUNCTRACE); 2090 res = symlook_obj(&req, obj); 2091 if (res == 0) { 2092 rtld_functrace = (void *)(req.defobj_out->relocbase + 2093 req.sym_out->st_value); 2094 rtld_functrace_obj = req.defobj_out; 2095 } 2096 } 2097 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2098 return 0; 2099 } 2100 2101 static const char * 2102 printable_path(const char *path) 2103 { 2104 2105 return (path == NULL ? "<unknown>" : path); 2106 } 2107 2108 /* 2109 * Load a shared object into memory, if it is not already loaded. The 2110 * object may be specified by name or by user-supplied file descriptor 2111 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2112 * duplicate is. 2113 * 2114 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2115 * on failure. 2116 */ 2117 static Obj_Entry * 2118 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2119 { 2120 Obj_Entry *obj; 2121 int fd; 2122 struct stat sb; 2123 char *path; 2124 2125 fd = -1; 2126 if (name != NULL) { 2127 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2128 if (object_match_name(obj, name)) 2129 return (obj); 2130 } 2131 2132 path = find_library(name, refobj, &fd); 2133 if (path == NULL) 2134 return (NULL); 2135 } else 2136 path = NULL; 2137 2138 if (fd >= 0) { 2139 /* 2140 * search_library_pathfds() opens a fresh file descriptor for the 2141 * library, so there is no need to dup(). 2142 */ 2143 } else if (fd_u == -1) { 2144 /* 2145 * If we didn't find a match by pathname, or the name is not 2146 * supplied, open the file and check again by device and inode. 2147 * This avoids false mismatches caused by multiple links or ".." 2148 * in pathnames. 2149 * 2150 * To avoid a race, we open the file and use fstat() rather than 2151 * using stat(). 2152 */ 2153 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) { 2154 _rtld_error("Cannot open \"%s\"", path); 2155 free(path); 2156 return (NULL); 2157 } 2158 } else { 2159 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2160 if (fd == -1) { 2161 _rtld_error("Cannot dup fd"); 2162 free(path); 2163 return (NULL); 2164 } 2165 } 2166 if (fstat(fd, &sb) == -1) { 2167 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2168 close(fd); 2169 free(path); 2170 return NULL; 2171 } 2172 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2173 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2174 break; 2175 if (obj != NULL && name != NULL) { 2176 object_add_name(obj, name); 2177 free(path); 2178 close(fd); 2179 return obj; 2180 } 2181 if (flags & RTLD_LO_NOLOAD) { 2182 free(path); 2183 close(fd); 2184 return (NULL); 2185 } 2186 2187 /* First use of this object, so we must map it in */ 2188 obj = do_load_object(fd, name, path, &sb, flags); 2189 if (obj == NULL) 2190 free(path); 2191 close(fd); 2192 2193 return obj; 2194 } 2195 2196 static Obj_Entry * 2197 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2198 int flags) 2199 { 2200 Obj_Entry *obj; 2201 struct statfs fs; 2202 2203 /* 2204 * but first, make sure that environment variables haven't been 2205 * used to circumvent the noexec flag on a filesystem. 2206 */ 2207 if (dangerous_ld_env) { 2208 if (fstatfs(fd, &fs) != 0) { 2209 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2210 return NULL; 2211 } 2212 if (fs.f_flags & MNT_NOEXEC) { 2213 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2214 return NULL; 2215 } 2216 } 2217 dbg("loading \"%s\"", printable_path(path)); 2218 obj = map_object(fd, printable_path(path), sbp); 2219 if (obj == NULL) 2220 return NULL; 2221 2222 /* 2223 * If DT_SONAME is present in the object, digest_dynamic2 already 2224 * added it to the object names. 2225 */ 2226 if (name != NULL) 2227 object_add_name(obj, name); 2228 obj->path = path; 2229 digest_dynamic(obj, 0); 2230 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2231 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2232 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2233 RTLD_LO_DLOPEN) { 2234 dbg("refusing to load non-loadable \"%s\"", obj->path); 2235 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2236 munmap(obj->mapbase, obj->mapsize); 2237 obj_free(obj); 2238 return (NULL); 2239 } 2240 2241 *obj_tail = obj; 2242 obj_tail = &obj->next; 2243 obj_count++; 2244 obj_loads++; 2245 linkmap_add(obj); /* for GDB & dlinfo() */ 2246 #if 0 2247 max_stack_flags |= obj->stack_flags; 2248 #endif 2249 2250 dbg(" %p .. %p: %s", obj->mapbase, 2251 obj->mapbase + obj->mapsize - 1, obj->path); 2252 if (obj->textrel) 2253 dbg(" WARNING: %s has impure text", obj->path); 2254 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2255 obj->path); 2256 2257 return obj; 2258 } 2259 2260 static Obj_Entry * 2261 obj_from_addr(const void *addr) 2262 { 2263 Obj_Entry *obj; 2264 2265 for (obj = obj_list; obj != NULL; obj = obj->next) { 2266 if (addr < (void *) obj->mapbase) 2267 continue; 2268 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2269 return obj; 2270 } 2271 return NULL; 2272 } 2273 2274 /* 2275 * If the main program is defined with a .preinit_array section, call 2276 * each function in order. This must occur before the initialization 2277 * of any shared object or the main program. 2278 */ 2279 static void 2280 preinit_main(void) 2281 { 2282 Elf_Addr *preinit_addr; 2283 int index; 2284 2285 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2286 if (preinit_addr == NULL) 2287 return; 2288 2289 for (index = 0; index < obj_main->preinit_array_num; index++) { 2290 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2291 dbg("calling preinit function for %s at %p", obj_main->path, 2292 (void *)preinit_addr[index]); 2293 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2294 0, 0, obj_main->path); 2295 call_init_pointer(obj_main, preinit_addr[index]); 2296 } 2297 } 2298 } 2299 2300 /* 2301 * Call the finalization functions for each of the objects in "list" 2302 * belonging to the DAG of "root" and referenced once. If NULL "root" 2303 * is specified, every finalization function will be called regardless 2304 * of the reference count and the list elements won't be freed. All of 2305 * the objects are expected to have non-NULL fini functions. 2306 */ 2307 static void 2308 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2309 { 2310 Objlist_Entry *elm; 2311 char *saved_msg; 2312 Elf_Addr *fini_addr; 2313 int index; 2314 2315 assert(root == NULL || root->refcount == 1); 2316 2317 /* 2318 * Preserve the current error message since a fini function might 2319 * call into the dynamic linker and overwrite it. 2320 */ 2321 saved_msg = errmsg_save(); 2322 do { 2323 STAILQ_FOREACH(elm, list, link) { 2324 if (root != NULL && (elm->obj->refcount != 1 || 2325 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2326 continue; 2327 2328 /* Remove object from fini list to prevent recursive invocation. */ 2329 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2330 /* 2331 * XXX: If a dlopen() call references an object while the 2332 * fini function is in progress, we might end up trying to 2333 * unload the referenced object in dlclose() or the object 2334 * won't be unloaded although its fini function has been 2335 * called. 2336 */ 2337 lock_release(rtld_bind_lock, lockstate); 2338 2339 /* 2340 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2341 * When this happens, DT_FINI_ARRAY is processed first. 2342 * It is also processed backwards. It is possible to encounter 2343 * DT_FINI_ARRAY elements with values of 0 or 1, but they need 2344 * to be ignored. 2345 */ 2346 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2347 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2348 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) { 2349 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2350 dbg("calling fini array function for %s at %p", 2351 elm->obj->path, (void *)fini_addr[index]); 2352 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2353 (void *)fini_addr[index], 0, 0, elm->obj->path); 2354 call_initfini_pointer(elm->obj, fini_addr[index]); 2355 } 2356 } 2357 } 2358 if (elm->obj->fini != (Elf_Addr)NULL) { 2359 dbg("calling fini function for %s at %p", elm->obj->path, 2360 (void *)elm->obj->fini); 2361 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2362 0, 0, elm->obj->path); 2363 call_initfini_pointer(elm->obj, elm->obj->fini); 2364 } 2365 wlock_acquire(rtld_bind_lock, lockstate); 2366 /* No need to free anything if process is going down. */ 2367 if (root != NULL) 2368 free(elm); 2369 /* 2370 * We must restart the list traversal after every fini call 2371 * because a dlclose() call from the fini function or from 2372 * another thread might have modified the reference counts. 2373 */ 2374 break; 2375 } 2376 } while (elm != NULL); 2377 errmsg_restore(saved_msg); 2378 } 2379 2380 /* 2381 * Call the initialization functions for each of the objects in 2382 * "list". All of the objects are expected to have non-NULL init 2383 * functions. 2384 */ 2385 static void 2386 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2387 { 2388 Objlist_Entry *elm; 2389 Obj_Entry *obj; 2390 char *saved_msg; 2391 Elf_Addr *init_addr; 2392 int index; 2393 2394 /* 2395 * Clean init_scanned flag so that objects can be rechecked and 2396 * possibly initialized earlier if any of vectors called below 2397 * cause the change by using dlopen. 2398 */ 2399 for (obj = obj_list; obj != NULL; obj = obj->next) 2400 obj->init_scanned = false; 2401 2402 /* 2403 * Preserve the current error message since an init function might 2404 * call into the dynamic linker and overwrite it. 2405 */ 2406 saved_msg = errmsg_save(); 2407 STAILQ_FOREACH(elm, list, link) { 2408 if (elm->obj->init_done) /* Initialized early. */ 2409 continue; 2410 2411 /* 2412 * Race: other thread might try to use this object before current 2413 * one completes the initilization. Not much can be done here 2414 * without better locking. 2415 */ 2416 elm->obj->init_done = true; 2417 lock_release(rtld_bind_lock, lockstate); 2418 2419 /* 2420 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2421 * When this happens, DT_INIT is processed first. 2422 * It is possible to encounter DT_INIT_ARRAY elements with values 2423 * of 0 or 1, but they need to be ignored. 2424 */ 2425 if (elm->obj->init != (Elf_Addr)NULL) { 2426 dbg("calling init function for %s at %p", elm->obj->path, 2427 (void *)elm->obj->init); 2428 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2429 0, 0, elm->obj->path); 2430 call_initfini_pointer(elm->obj, elm->obj->init); 2431 } 2432 init_addr = (Elf_Addr *)elm->obj->init_array; 2433 if (init_addr != NULL) { 2434 for (index = 0; index < elm->obj->init_array_num; index++) { 2435 if (init_addr[index] != 0 && init_addr[index] != 1) { 2436 dbg("calling init array function for %s at %p", elm->obj->path, 2437 (void *)init_addr[index]); 2438 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2439 (void *)init_addr[index], 0, 0, elm->obj->path); 2440 call_init_pointer(elm->obj, init_addr[index]); 2441 } 2442 } 2443 } 2444 wlock_acquire(rtld_bind_lock, lockstate); 2445 } 2446 errmsg_restore(saved_msg); 2447 } 2448 2449 static void 2450 objlist_clear(Objlist *list) 2451 { 2452 Objlist_Entry *elm; 2453 2454 while (!STAILQ_EMPTY(list)) { 2455 elm = STAILQ_FIRST(list); 2456 STAILQ_REMOVE_HEAD(list, link); 2457 free(elm); 2458 } 2459 } 2460 2461 static Objlist_Entry * 2462 objlist_find(Objlist *list, const Obj_Entry *obj) 2463 { 2464 Objlist_Entry *elm; 2465 2466 STAILQ_FOREACH(elm, list, link) 2467 if (elm->obj == obj) 2468 return elm; 2469 return NULL; 2470 } 2471 2472 static void 2473 objlist_init(Objlist *list) 2474 { 2475 STAILQ_INIT(list); 2476 } 2477 2478 static void 2479 objlist_push_head(Objlist *list, Obj_Entry *obj) 2480 { 2481 Objlist_Entry *elm; 2482 2483 elm = NEW(Objlist_Entry); 2484 elm->obj = obj; 2485 STAILQ_INSERT_HEAD(list, elm, link); 2486 } 2487 2488 static void 2489 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2490 { 2491 Objlist_Entry *elm; 2492 2493 elm = NEW(Objlist_Entry); 2494 elm->obj = obj; 2495 STAILQ_INSERT_TAIL(list, elm, link); 2496 } 2497 2498 static void 2499 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2500 { 2501 Objlist_Entry *elm, *listelm; 2502 2503 STAILQ_FOREACH(listelm, list, link) { 2504 if (listelm->obj == listobj) 2505 break; 2506 } 2507 elm = NEW(Objlist_Entry); 2508 elm->obj = obj; 2509 if (listelm != NULL) 2510 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2511 else 2512 STAILQ_INSERT_TAIL(list, elm, link); 2513 } 2514 2515 static void 2516 objlist_remove(Objlist *list, Obj_Entry *obj) 2517 { 2518 Objlist_Entry *elm; 2519 2520 if ((elm = objlist_find(list, obj)) != NULL) { 2521 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2522 free(elm); 2523 } 2524 } 2525 2526 /* 2527 * Relocate dag rooted in the specified object. 2528 * Returns 0 on success, or -1 on failure. 2529 */ 2530 2531 static int 2532 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2533 int flags, RtldLockState *lockstate) 2534 { 2535 Objlist_Entry *elm; 2536 int error; 2537 2538 error = 0; 2539 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2540 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2541 lockstate); 2542 if (error == -1) 2543 break; 2544 } 2545 return (error); 2546 } 2547 2548 /* 2549 * Prepare for, or clean after, relocating an object marked with 2550 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only 2551 * segments are remapped read-write. After relocations are done, the 2552 * segment's permissions are returned back to the modes specified in 2553 * the phdrs. If any relocation happened, or always for wired 2554 * program, COW is triggered. 2555 */ 2556 static int 2557 reloc_textrel_prot(Obj_Entry *obj, bool before) 2558 { 2559 const Elf_Phdr *ph; 2560 void *base; 2561 size_t l, sz; 2562 int prot; 2563 2564 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0; 2565 l--, ph++) { 2566 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) 2567 continue; 2568 base = obj->relocbase + trunc_page(ph->p_vaddr); 2569 sz = round_page(ph->p_vaddr + ph->p_filesz) - 2570 trunc_page(ph->p_vaddr); 2571 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0); 2572 /* 2573 * Make sure modified text segments are included in the 2574 * core dump since we modified it. This unfortunately causes the 2575 * entire text segment to core-out but we don't have much of a 2576 * choice. We could try to only reenable core dumps on pages 2577 * in which relocations occured but that is likely most of the text 2578 * pages anyway, and even that would not work because the rest of 2579 * the text pages would wind up as a read-only OBJT_DEFAULT object 2580 * (created due to our modifications) backed by the original OBJT_VNODE 2581 * object, and the ELF coredump code is currently only able to dump 2582 * vnode records for pure vnode-backed mappings, not vnode backings 2583 * to memory objects. 2584 */ 2585 if (before == false) 2586 madvise(base, sz, MADV_CORE); 2587 if (mprotect(base, sz, prot) == -1) { 2588 _rtld_error("%s: Cannot write-%sable text segment: %s", 2589 obj->path, before ? "en" : "dis", 2590 rtld_strerror(errno)); 2591 return (-1); 2592 } 2593 } 2594 return (0); 2595 } 2596 2597 /* 2598 * Relocate single object. 2599 * Returns 0 on success, or -1 on failure. 2600 */ 2601 static int 2602 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2603 int flags, RtldLockState *lockstate) 2604 { 2605 2606 if (obj->relocated) 2607 return (0); 2608 obj->relocated = true; 2609 if (obj != rtldobj) 2610 dbg("relocating \"%s\"", obj->path); 2611 2612 if (obj->symtab == NULL || obj->strtab == NULL || 2613 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2614 _rtld_error("%s: Shared object has no run-time symbol table", 2615 obj->path); 2616 return (-1); 2617 } 2618 2619 /* There are relocations to the write-protected text segment. */ 2620 if (obj->textrel && reloc_textrel_prot(obj, true) != 0) 2621 return (-1); 2622 2623 /* Process the non-PLT non-IFUNC relocations. */ 2624 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2625 return (-1); 2626 2627 /* Re-protected the text segment. */ 2628 if (obj->textrel && reloc_textrel_prot(obj, false) != 0) 2629 return (-1); 2630 2631 /* Set the special PLT or GOT entries. */ 2632 init_pltgot(obj); 2633 2634 /* Process the PLT relocations. */ 2635 if (reloc_plt(obj) == -1) 2636 return (-1); 2637 /* Relocate the jump slots if we are doing immediate binding. */ 2638 if (obj->bind_now || bind_now) 2639 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2640 return (-1); 2641 2642 /* 2643 * Process the non-PLT IFUNC relocations. The relocations are 2644 * processed in two phases, because IFUNC resolvers may 2645 * reference other symbols, which must be readily processed 2646 * before resolvers are called. 2647 */ 2648 if (obj->non_plt_gnu_ifunc && 2649 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2650 return (-1); 2651 2652 /* 2653 * Set up the magic number and version in the Obj_Entry. These 2654 * were checked in the crt1.o from the original ElfKit, so we 2655 * set them for backward compatibility. 2656 */ 2657 obj->magic = RTLD_MAGIC; 2658 obj->version = RTLD_VERSION; 2659 2660 /* 2661 * Set relocated data to read-only status if protection specified 2662 */ 2663 2664 if (obj->relro_size) { 2665 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) { 2666 _rtld_error("%s: Cannot enforce relro relocation: %s", 2667 obj->path, rtld_strerror(errno)); 2668 return (-1); 2669 } 2670 } 2671 return (0); 2672 } 2673 2674 /* 2675 * Relocate newly-loaded shared objects. The argument is a pointer to 2676 * the Obj_Entry for the first such object. All objects from the first 2677 * to the end of the list of objects are relocated. Returns 0 on success, 2678 * or -1 on failure. 2679 */ 2680 static int 2681 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2682 int flags, RtldLockState *lockstate) 2683 { 2684 Obj_Entry *obj; 2685 int error; 2686 2687 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2688 error = relocate_object(obj, bind_now, rtldobj, flags, 2689 lockstate); 2690 if (error == -1) 2691 break; 2692 } 2693 return (error); 2694 } 2695 2696 /* 2697 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2698 * referencing STT_GNU_IFUNC symbols is postponed till the other 2699 * relocations are done. The indirect functions specified as 2700 * ifunc are allowed to call other symbols, so we need to have 2701 * objects relocated before asking for resolution from indirects. 2702 * 2703 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2704 * instead of the usual lazy handling of PLT slots. It is 2705 * consistent with how GNU does it. 2706 */ 2707 static int 2708 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2709 RtldLockState *lockstate) 2710 { 2711 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2712 return (-1); 2713 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2714 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2715 return (-1); 2716 return (0); 2717 } 2718 2719 static int 2720 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2721 RtldLockState *lockstate) 2722 { 2723 Obj_Entry *obj; 2724 2725 for (obj = first; obj != NULL; obj = obj->next) { 2726 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2727 return (-1); 2728 } 2729 return (0); 2730 } 2731 2732 static int 2733 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2734 RtldLockState *lockstate) 2735 { 2736 Objlist_Entry *elm; 2737 2738 STAILQ_FOREACH(elm, list, link) { 2739 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2740 lockstate) == -1) 2741 return (-1); 2742 } 2743 return (0); 2744 } 2745 2746 /* 2747 * Cleanup procedure. It will be called (by the atexit mechanism) just 2748 * before the process exits. 2749 */ 2750 static void 2751 rtld_exit(void) 2752 { 2753 RtldLockState lockstate; 2754 2755 wlock_acquire(rtld_bind_lock, &lockstate); 2756 dbg("rtld_exit()"); 2757 objlist_call_fini(&list_fini, NULL, &lockstate); 2758 /* No need to remove the items from the list, since we are exiting. */ 2759 if (!libmap_disable) 2760 lm_fini(); 2761 lock_release(rtld_bind_lock, &lockstate); 2762 } 2763 2764 /* 2765 * Iterate over a search path, translate each element, and invoke the 2766 * callback on the result. 2767 */ 2768 static void * 2769 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2770 { 2771 const char *trans; 2772 if (path == NULL) 2773 return (NULL); 2774 2775 path += strspn(path, ":;"); 2776 while (*path != '\0') { 2777 size_t len; 2778 char *res; 2779 2780 len = strcspn(path, ":;"); 2781 trans = lm_findn(NULL, path, len); 2782 if (trans) 2783 res = callback(trans, strlen(trans), arg); 2784 else 2785 res = callback(path, len, arg); 2786 2787 if (res != NULL) 2788 return (res); 2789 2790 path += len; 2791 path += strspn(path, ":;"); 2792 } 2793 2794 return (NULL); 2795 } 2796 2797 struct try_library_args { 2798 const char *name; 2799 size_t namelen; 2800 char *buffer; 2801 size_t buflen; 2802 }; 2803 2804 static void * 2805 try_library_path(const char *dir, size_t dirlen, void *param) 2806 { 2807 struct try_library_args *arg; 2808 2809 arg = param; 2810 if (*dir == '/' || trust) { 2811 char *pathname; 2812 2813 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2814 return (NULL); 2815 2816 pathname = arg->buffer; 2817 strncpy(pathname, dir, dirlen); 2818 pathname[dirlen] = '/'; 2819 strcpy(pathname + dirlen + 1, arg->name); 2820 2821 dbg(" Trying \"%s\"", pathname); 2822 if (access(pathname, F_OK) == 0) { /* We found it */ 2823 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2824 strcpy(pathname, arg->buffer); 2825 return (pathname); 2826 } 2827 } 2828 return (NULL); 2829 } 2830 2831 static char * 2832 search_library_path(const char *name, const char *path) 2833 { 2834 char *p; 2835 struct try_library_args arg; 2836 2837 if (path == NULL) 2838 return NULL; 2839 2840 arg.name = name; 2841 arg.namelen = strlen(name); 2842 arg.buffer = xmalloc(PATH_MAX); 2843 arg.buflen = PATH_MAX; 2844 2845 p = path_enumerate(path, try_library_path, &arg); 2846 2847 free(arg.buffer); 2848 2849 return (p); 2850 } 2851 2852 2853 /* 2854 * Finds the library with the given name using the directory descriptors 2855 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2856 * 2857 * Returns a freshly-opened close-on-exec file descriptor for the library, 2858 * or -1 if the library cannot be found. 2859 */ 2860 static char * 2861 search_library_pathfds(const char *name, const char *path, int *fdp) 2862 { 2863 char *envcopy, *fdstr, *found, *last_token; 2864 size_t len; 2865 int dirfd, fd; 2866 2867 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2868 2869 /* Don't load from user-specified libdirs into setuid binaries. */ 2870 if (!trust) 2871 return (NULL); 2872 2873 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2874 if (path == NULL) 2875 return (NULL); 2876 2877 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2878 if (name[0] == '/') { 2879 dbg("Absolute path (%s) passed to %s", name, __func__); 2880 return (NULL); 2881 } 2882 2883 /* 2884 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2885 * copy of the path, as strtok_r rewrites separator tokens 2886 * with '\0'. 2887 */ 2888 found = NULL; 2889 envcopy = xstrdup(path); 2890 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2891 fdstr = strtok_r(NULL, ":", &last_token)) { 2892 dirfd = parse_libdir(fdstr); 2893 if (dirfd < 0) 2894 break; 2895 fd = openat(dirfd, name, O_RDONLY | O_CLOEXEC); 2896 if (fd >= 0) { 2897 *fdp = fd; 2898 len = strlen(fdstr) + strlen(name) + 3; 2899 found = xmalloc(len); 2900 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2901 _rtld_error("error generating '%d/%s'", 2902 dirfd, name); 2903 die(); 2904 } 2905 dbg("open('%s') => %d", found, fd); 2906 break; 2907 } 2908 } 2909 free(envcopy); 2910 2911 return (found); 2912 } 2913 2914 2915 int 2916 dlclose(void *handle) 2917 { 2918 Obj_Entry *root; 2919 RtldLockState lockstate; 2920 2921 wlock_acquire(rtld_bind_lock, &lockstate); 2922 root = dlcheck(handle); 2923 if (root == NULL) { 2924 lock_release(rtld_bind_lock, &lockstate); 2925 return -1; 2926 } 2927 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2928 root->path); 2929 2930 /* Unreference the object and its dependencies. */ 2931 root->dl_refcount--; 2932 2933 if (root->refcount == 1) { 2934 /* 2935 * The object will be no longer referenced, so we must unload it. 2936 * First, call the fini functions. 2937 */ 2938 objlist_call_fini(&list_fini, root, &lockstate); 2939 2940 unref_dag(root); 2941 2942 /* Finish cleaning up the newly-unreferenced objects. */ 2943 GDB_STATE(RT_DELETE,&root->linkmap); 2944 unload_object(root); 2945 GDB_STATE(RT_CONSISTENT,NULL); 2946 } else 2947 unref_dag(root); 2948 2949 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2950 lock_release(rtld_bind_lock, &lockstate); 2951 return 0; 2952 } 2953 2954 char * 2955 dlerror(void) 2956 { 2957 char *msg = error_message; 2958 error_message = NULL; 2959 return msg; 2960 } 2961 2962 void * 2963 dlopen(const char *name, int mode) 2964 { 2965 2966 return (rtld_dlopen(name, -1, mode)); 2967 } 2968 2969 void * 2970 fdlopen(int fd, int mode) 2971 { 2972 2973 return (rtld_dlopen(NULL, fd, mode)); 2974 } 2975 2976 static void * 2977 rtld_dlopen(const char *name, int fd, int mode) 2978 { 2979 RtldLockState lockstate; 2980 int lo_flags; 2981 2982 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2983 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2984 if (ld_tracing != NULL) { 2985 rlock_acquire(rtld_bind_lock, &lockstate); 2986 if (sigsetjmp(lockstate.env, 0) != 0) 2987 lock_upgrade(rtld_bind_lock, &lockstate); 2988 environ = (char **)*get_program_var_addr("environ", &lockstate); 2989 lock_release(rtld_bind_lock, &lockstate); 2990 } 2991 lo_flags = RTLD_LO_DLOPEN; 2992 if (mode & RTLD_NODELETE) 2993 lo_flags |= RTLD_LO_NODELETE; 2994 if (mode & RTLD_NOLOAD) 2995 lo_flags |= RTLD_LO_NOLOAD; 2996 if (ld_tracing != NULL) 2997 lo_flags |= RTLD_LO_TRACE; 2998 2999 return (dlopen_object(name, fd, obj_main, lo_flags, 3000 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 3001 } 3002 3003 static void 3004 dlopen_cleanup(Obj_Entry *obj) 3005 { 3006 3007 obj->dl_refcount--; 3008 unref_dag(obj); 3009 if (obj->refcount == 0) 3010 unload_object(obj); 3011 } 3012 3013 static Obj_Entry * 3014 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3015 int mode, RtldLockState *lockstate) 3016 { 3017 Obj_Entry **old_obj_tail; 3018 Obj_Entry *obj; 3019 Objlist initlist; 3020 RtldLockState mlockstate; 3021 int result; 3022 3023 objlist_init(&initlist); 3024 3025 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3026 wlock_acquire(rtld_bind_lock, &mlockstate); 3027 lockstate = &mlockstate; 3028 } 3029 GDB_STATE(RT_ADD,NULL); 3030 3031 old_obj_tail = obj_tail; 3032 obj = NULL; 3033 if (name == NULL && fd == -1) { 3034 obj = obj_main; 3035 obj->refcount++; 3036 } else { 3037 obj = load_object(name, fd, refobj, lo_flags); 3038 } 3039 3040 if (obj) { 3041 obj->dl_refcount++; 3042 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3043 objlist_push_tail(&list_global, obj); 3044 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3045 assert(*old_obj_tail == obj); 3046 result = load_needed_objects(obj, 3047 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3048 init_dag(obj); 3049 ref_dag(obj); 3050 if (result != -1) 3051 result = rtld_verify_versions(&obj->dagmembers); 3052 if (result != -1 && ld_tracing) 3053 goto trace; 3054 if (result == -1 || relocate_object_dag(obj, 3055 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3056 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3057 lockstate) == -1) { 3058 dlopen_cleanup(obj); 3059 obj = NULL; 3060 } else if (lo_flags & RTLD_LO_EARLY) { 3061 /* 3062 * Do not call the init functions for early loaded 3063 * filtees. The image is still not initialized enough 3064 * for them to work. 3065 * 3066 * Our object is found by the global object list and 3067 * will be ordered among all init calls done right 3068 * before transferring control to main. 3069 */ 3070 } else { 3071 /* Make list of init functions to call. */ 3072 initlist_add_objects(obj, &obj->next, &initlist); 3073 } 3074 /* 3075 * Process all no_delete objects here, given them own 3076 * DAGs to prevent their dependencies from being unloaded. 3077 * This has to be done after we have loaded all of the 3078 * dependencies, so that we do not miss any. 3079 */ 3080 if (obj != NULL) 3081 process_nodelete(obj); 3082 } else { 3083 /* 3084 * Bump the reference counts for objects on this DAG. If 3085 * this is the first dlopen() call for the object that was 3086 * already loaded as a dependency, initialize the dag 3087 * starting at it. 3088 */ 3089 init_dag(obj); 3090 ref_dag(obj); 3091 3092 if ((lo_flags & RTLD_LO_TRACE) != 0) 3093 goto trace; 3094 } 3095 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3096 obj->z_nodelete) && !obj->ref_nodel) { 3097 dbg("obj %s nodelete", obj->path); 3098 ref_dag(obj); 3099 obj->z_nodelete = obj->ref_nodel = true; 3100 } 3101 } 3102 3103 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3104 name); 3105 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3106 3107 if (!(lo_flags & RTLD_LO_EARLY)) { 3108 map_stacks_exec(lockstate); 3109 } 3110 3111 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3112 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3113 lockstate) == -1) { 3114 objlist_clear(&initlist); 3115 dlopen_cleanup(obj); 3116 if (lockstate == &mlockstate) 3117 lock_release(rtld_bind_lock, lockstate); 3118 return (NULL); 3119 } 3120 3121 if (!(lo_flags & RTLD_LO_EARLY)) { 3122 /* Call the init functions. */ 3123 objlist_call_init(&initlist, lockstate); 3124 } 3125 objlist_clear(&initlist); 3126 if (lockstate == &mlockstate) 3127 lock_release(rtld_bind_lock, lockstate); 3128 return obj; 3129 trace: 3130 trace_loaded_objects(obj); 3131 if (lockstate == &mlockstate) 3132 lock_release(rtld_bind_lock, lockstate); 3133 exit(0); 3134 } 3135 3136 static void * 3137 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3138 int flags) 3139 { 3140 DoneList donelist; 3141 const Obj_Entry *obj, *defobj; 3142 const Elf_Sym *def; 3143 SymLook req; 3144 RtldLockState lockstate; 3145 tls_index ti; 3146 int res; 3147 3148 def = NULL; 3149 defobj = NULL; 3150 symlook_init(&req, name); 3151 req.ventry = ve; 3152 req.flags = flags | SYMLOOK_IN_PLT; 3153 req.lockstate = &lockstate; 3154 3155 rlock_acquire(rtld_bind_lock, &lockstate); 3156 if (sigsetjmp(lockstate.env, 0) != 0) 3157 lock_upgrade(rtld_bind_lock, &lockstate); 3158 if (handle == NULL || handle == RTLD_NEXT || 3159 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3160 3161 if ((obj = obj_from_addr(retaddr)) == NULL) { 3162 _rtld_error("Cannot determine caller's shared object"); 3163 lock_release(rtld_bind_lock, &lockstate); 3164 return NULL; 3165 } 3166 if (handle == NULL) { /* Just the caller's shared object. */ 3167 res = symlook_obj(&req, obj); 3168 if (res == 0) { 3169 def = req.sym_out; 3170 defobj = req.defobj_out; 3171 } 3172 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3173 handle == RTLD_SELF) { /* ... caller included */ 3174 if (handle == RTLD_NEXT) 3175 obj = obj->next; 3176 for (; obj != NULL; obj = obj->next) { 3177 res = symlook_obj(&req, obj); 3178 if (res == 0) { 3179 if (def == NULL || 3180 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3181 def = req.sym_out; 3182 defobj = req.defobj_out; 3183 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3184 break; 3185 } 3186 } 3187 } 3188 /* 3189 * Search the dynamic linker itself, and possibly resolve the 3190 * symbol from there. This is how the application links to 3191 * dynamic linker services such as dlopen. 3192 */ 3193 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3194 res = symlook_obj(&req, &obj_rtld); 3195 if (res == 0) { 3196 def = req.sym_out; 3197 defobj = req.defobj_out; 3198 } 3199 } 3200 } else { 3201 assert(handle == RTLD_DEFAULT); 3202 res = symlook_default(&req, obj); 3203 if (res == 0) { 3204 defobj = req.defobj_out; 3205 def = req.sym_out; 3206 } 3207 } 3208 } else { 3209 if ((obj = dlcheck(handle)) == NULL) { 3210 lock_release(rtld_bind_lock, &lockstate); 3211 return NULL; 3212 } 3213 3214 donelist_init(&donelist); 3215 if (obj->mainprog) { 3216 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3217 res = symlook_global(&req, &donelist); 3218 if (res == 0) { 3219 def = req.sym_out; 3220 defobj = req.defobj_out; 3221 } 3222 /* 3223 * Search the dynamic linker itself, and possibly resolve the 3224 * symbol from there. This is how the application links to 3225 * dynamic linker services such as dlopen. 3226 */ 3227 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3228 res = symlook_obj(&req, &obj_rtld); 3229 if (res == 0) { 3230 def = req.sym_out; 3231 defobj = req.defobj_out; 3232 } 3233 } 3234 } 3235 else { 3236 /* Search the whole DAG rooted at the given object. */ 3237 res = symlook_list(&req, &obj->dagmembers, &donelist); 3238 if (res == 0) { 3239 def = req.sym_out; 3240 defobj = req.defobj_out; 3241 } 3242 } 3243 } 3244 3245 if (def != NULL) { 3246 lock_release(rtld_bind_lock, &lockstate); 3247 3248 /* 3249 * The value required by the caller is derived from the value 3250 * of the symbol. this is simply the relocated value of the 3251 * symbol. 3252 */ 3253 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3254 return (make_function_pointer(def, defobj)); 3255 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3256 return (rtld_resolve_ifunc(defobj, def)); 3257 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3258 ti.ti_module = defobj->tlsindex; 3259 ti.ti_offset = def->st_value; 3260 return (__tls_get_addr(&ti)); 3261 } else 3262 return (defobj->relocbase + def->st_value); 3263 } 3264 3265 _rtld_error("Undefined symbol \"%s\"", name); 3266 lock_release(rtld_bind_lock, &lockstate); 3267 return NULL; 3268 } 3269 3270 void * 3271 dlsym(void *handle, const char *name) 3272 { 3273 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3274 SYMLOOK_DLSYM); 3275 } 3276 3277 dlfunc_t 3278 dlfunc(void *handle, const char *name) 3279 { 3280 union { 3281 void *d; 3282 dlfunc_t f; 3283 } rv; 3284 3285 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3286 SYMLOOK_DLSYM); 3287 return (rv.f); 3288 } 3289 3290 void * 3291 dlvsym(void *handle, const char *name, const char *version) 3292 { 3293 Ver_Entry ventry; 3294 3295 ventry.name = version; 3296 ventry.file = NULL; 3297 ventry.hash = elf_hash(version); 3298 ventry.flags= 0; 3299 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3300 SYMLOOK_DLSYM); 3301 } 3302 3303 int 3304 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3305 { 3306 const Obj_Entry *obj; 3307 RtldLockState lockstate; 3308 3309 rlock_acquire(rtld_bind_lock, &lockstate); 3310 obj = obj_from_addr(addr); 3311 if (obj == NULL) { 3312 _rtld_error("No shared object contains address"); 3313 lock_release(rtld_bind_lock, &lockstate); 3314 return (0); 3315 } 3316 rtld_fill_dl_phdr_info(obj, phdr_info); 3317 lock_release(rtld_bind_lock, &lockstate); 3318 return (1); 3319 } 3320 3321 int 3322 dladdr(const void *addr, Dl_info *info) 3323 { 3324 const Obj_Entry *obj; 3325 const Elf_Sym *def; 3326 void *symbol_addr; 3327 unsigned long symoffset; 3328 RtldLockState lockstate; 3329 3330 rlock_acquire(rtld_bind_lock, &lockstate); 3331 obj = obj_from_addr(addr); 3332 if (obj == NULL) { 3333 _rtld_error("No shared object contains address"); 3334 lock_release(rtld_bind_lock, &lockstate); 3335 return 0; 3336 } 3337 info->dli_fname = obj->path; 3338 info->dli_fbase = obj->mapbase; 3339 info->dli_saddr = NULL; 3340 info->dli_sname = NULL; 3341 3342 /* 3343 * Walk the symbol list looking for the symbol whose address is 3344 * closest to the address sent in. 3345 */ 3346 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3347 def = obj->symtab + symoffset; 3348 3349 /* 3350 * For skip the symbol if st_shndx is either SHN_UNDEF or 3351 * SHN_COMMON. 3352 */ 3353 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3354 continue; 3355 3356 /* 3357 * If the symbol is greater than the specified address, or if it 3358 * is further away from addr than the current nearest symbol, 3359 * then reject it. 3360 */ 3361 symbol_addr = obj->relocbase + def->st_value; 3362 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3363 continue; 3364 3365 /* Update our idea of the nearest symbol. */ 3366 info->dli_sname = obj->strtab + def->st_name; 3367 info->dli_saddr = symbol_addr; 3368 3369 /* Exact match? */ 3370 if (info->dli_saddr == addr) 3371 break; 3372 } 3373 lock_release(rtld_bind_lock, &lockstate); 3374 return 1; 3375 } 3376 3377 int 3378 dlinfo(void *handle, int request, void *p) 3379 { 3380 const Obj_Entry *obj; 3381 RtldLockState lockstate; 3382 int error; 3383 3384 rlock_acquire(rtld_bind_lock, &lockstate); 3385 3386 if (handle == NULL || handle == RTLD_SELF) { 3387 void *retaddr; 3388 3389 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3390 if ((obj = obj_from_addr(retaddr)) == NULL) 3391 _rtld_error("Cannot determine caller's shared object"); 3392 } else 3393 obj = dlcheck(handle); 3394 3395 if (obj == NULL) { 3396 lock_release(rtld_bind_lock, &lockstate); 3397 return (-1); 3398 } 3399 3400 error = 0; 3401 switch (request) { 3402 case RTLD_DI_LINKMAP: 3403 *((struct link_map const **)p) = &obj->linkmap; 3404 break; 3405 case RTLD_DI_ORIGIN: 3406 error = rtld_dirname(obj->path, p); 3407 break; 3408 3409 case RTLD_DI_SERINFOSIZE: 3410 case RTLD_DI_SERINFO: 3411 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3412 break; 3413 3414 default: 3415 _rtld_error("Invalid request %d passed to dlinfo()", request); 3416 error = -1; 3417 } 3418 3419 lock_release(rtld_bind_lock, &lockstate); 3420 3421 return (error); 3422 } 3423 3424 static void 3425 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3426 { 3427 3428 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3429 phdr_info->dlpi_name = obj->path; 3430 phdr_info->dlpi_phdr = obj->phdr; 3431 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3432 phdr_info->dlpi_tls_modid = obj->tlsindex; 3433 phdr_info->dlpi_tls_data = obj->tlsinit; 3434 phdr_info->dlpi_adds = obj_loads; 3435 phdr_info->dlpi_subs = obj_loads - obj_count; 3436 } 3437 3438 int 3439 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3440 { 3441 struct dl_phdr_info phdr_info; 3442 const Obj_Entry *obj; 3443 RtldLockState bind_lockstate, phdr_lockstate; 3444 int error; 3445 3446 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3447 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3448 3449 error = 0; 3450 3451 for (obj = obj_list; obj != NULL; obj = obj->next) { 3452 rtld_fill_dl_phdr_info(obj, &phdr_info); 3453 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3454 break; 3455 3456 } 3457 if (error == 0) { 3458 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3459 error = callback(&phdr_info, sizeof(phdr_info), param); 3460 } 3461 3462 lock_release(rtld_bind_lock, &bind_lockstate); 3463 lock_release(rtld_phdr_lock, &phdr_lockstate); 3464 3465 return (error); 3466 } 3467 3468 static void * 3469 fill_search_info(const char *dir, size_t dirlen, void *param) 3470 { 3471 struct fill_search_info_args *arg; 3472 3473 arg = param; 3474 3475 if (arg->request == RTLD_DI_SERINFOSIZE) { 3476 arg->serinfo->dls_cnt ++; 3477 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3478 } else { 3479 struct dl_serpath *s_entry; 3480 3481 s_entry = arg->serpath; 3482 s_entry->dls_name = arg->strspace; 3483 s_entry->dls_flags = arg->flags; 3484 3485 strncpy(arg->strspace, dir, dirlen); 3486 arg->strspace[dirlen] = '\0'; 3487 3488 arg->strspace += dirlen + 1; 3489 arg->serpath++; 3490 } 3491 3492 return (NULL); 3493 } 3494 3495 static int 3496 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3497 { 3498 struct dl_serinfo _info; 3499 struct fill_search_info_args args; 3500 3501 args.request = RTLD_DI_SERINFOSIZE; 3502 args.serinfo = &_info; 3503 3504 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3505 _info.dls_cnt = 0; 3506 3507 path_enumerate(obj->rpath, fill_search_info, &args); 3508 path_enumerate(ld_library_path, fill_search_info, &args); 3509 path_enumerate(obj->runpath, fill_search_info, &args); 3510 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3511 if (!obj->z_nodeflib) 3512 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3513 3514 3515 if (request == RTLD_DI_SERINFOSIZE) { 3516 info->dls_size = _info.dls_size; 3517 info->dls_cnt = _info.dls_cnt; 3518 return (0); 3519 } 3520 3521 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3522 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3523 return (-1); 3524 } 3525 3526 args.request = RTLD_DI_SERINFO; 3527 args.serinfo = info; 3528 args.serpath = &info->dls_serpath[0]; 3529 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3530 3531 args.flags = LA_SER_RUNPATH; 3532 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3533 return (-1); 3534 3535 args.flags = LA_SER_LIBPATH; 3536 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3537 return (-1); 3538 3539 args.flags = LA_SER_RUNPATH; 3540 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3541 return (-1); 3542 3543 args.flags = LA_SER_CONFIG; 3544 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3545 != NULL) 3546 return (-1); 3547 3548 args.flags = LA_SER_DEFAULT; 3549 if (!obj->z_nodeflib && 3550 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3551 return (-1); 3552 return (0); 3553 } 3554 3555 static int 3556 rtld_dirname(const char *path, char *bname) 3557 { 3558 const char *endp; 3559 3560 /* Empty or NULL string gets treated as "." */ 3561 if (path == NULL || *path == '\0') { 3562 bname[0] = '.'; 3563 bname[1] = '\0'; 3564 return (0); 3565 } 3566 3567 /* Strip trailing slashes */ 3568 endp = path + strlen(path) - 1; 3569 while (endp > path && *endp == '/') 3570 endp--; 3571 3572 /* Find the start of the dir */ 3573 while (endp > path && *endp != '/') 3574 endp--; 3575 3576 /* Either the dir is "/" or there are no slashes */ 3577 if (endp == path) { 3578 bname[0] = *endp == '/' ? '/' : '.'; 3579 bname[1] = '\0'; 3580 return (0); 3581 } else { 3582 do { 3583 endp--; 3584 } while (endp > path && *endp == '/'); 3585 } 3586 3587 if (endp - path + 2 > PATH_MAX) 3588 { 3589 _rtld_error("Filename is too long: %s", path); 3590 return(-1); 3591 } 3592 3593 strncpy(bname, path, endp - path + 1); 3594 bname[endp - path + 1] = '\0'; 3595 return (0); 3596 } 3597 3598 static int 3599 rtld_dirname_abs(const char *path, char *base) 3600 { 3601 char base_rel[PATH_MAX]; 3602 3603 if (rtld_dirname(path, base) == -1) 3604 return (-1); 3605 if (base[0] == '/') 3606 return (0); 3607 if (getcwd(base_rel, sizeof(base_rel)) == NULL || 3608 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) || 3609 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel)) 3610 return (-1); 3611 strcpy(base, base_rel); 3612 return (0); 3613 } 3614 3615 static void 3616 linkmap_add(Obj_Entry *obj) 3617 { 3618 struct link_map *l = &obj->linkmap; 3619 struct link_map *prev; 3620 3621 obj->linkmap.l_name = obj->path; 3622 obj->linkmap.l_addr = obj->mapbase; 3623 obj->linkmap.l_ld = obj->dynamic; 3624 3625 if (r_debug.r_map == NULL) { 3626 r_debug.r_map = l; 3627 return; 3628 } 3629 3630 /* 3631 * Scan to the end of the list, but not past the entry for the 3632 * dynamic linker, which we want to keep at the very end. 3633 */ 3634 for (prev = r_debug.r_map; 3635 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3636 prev = prev->l_next) 3637 ; 3638 3639 /* Link in the new entry. */ 3640 l->l_prev = prev; 3641 l->l_next = prev->l_next; 3642 if (l->l_next != NULL) 3643 l->l_next->l_prev = l; 3644 prev->l_next = l; 3645 } 3646 3647 static void 3648 linkmap_delete(Obj_Entry *obj) 3649 { 3650 struct link_map *l = &obj->linkmap; 3651 3652 if (l->l_prev == NULL) { 3653 if ((r_debug.r_map = l->l_next) != NULL) 3654 l->l_next->l_prev = NULL; 3655 return; 3656 } 3657 3658 if ((l->l_prev->l_next = l->l_next) != NULL) 3659 l->l_next->l_prev = l->l_prev; 3660 } 3661 3662 /* 3663 * Function for the debugger to set a breakpoint on to gain control. 3664 * 3665 * The two parameters allow the debugger to easily find and determine 3666 * what the runtime loader is doing and to whom it is doing it. 3667 * 3668 * When the loadhook trap is hit (r_debug_state, set at program 3669 * initialization), the arguments can be found on the stack: 3670 * 3671 * +8 struct link_map *m 3672 * +4 struct r_debug *rd 3673 * +0 RetAddr 3674 */ 3675 void 3676 r_debug_state(struct r_debug* rd, struct link_map *m) 3677 { 3678 /* 3679 * The following is a hack to force the compiler to emit calls to 3680 * this function, even when optimizing. If the function is empty, 3681 * the compiler is not obliged to emit any code for calls to it, 3682 * even when marked __noinline. However, gdb depends on those 3683 * calls being made. 3684 */ 3685 __asm __volatile("" : : : "memory"); 3686 } 3687 3688 /* 3689 * A function called after init routines have completed. This can be used to 3690 * break before a program's entry routine is called, and can be used when 3691 * main is not available in the symbol table. 3692 */ 3693 void 3694 _r_debug_postinit(struct link_map *m) 3695 { 3696 3697 /* See r_debug_state(). */ 3698 __asm __volatile("" : : : "memory"); 3699 } 3700 3701 /* 3702 * Get address of the pointer variable in the main program. 3703 * Prefer non-weak symbol over the weak one. 3704 */ 3705 static const void ** 3706 get_program_var_addr(const char *name, RtldLockState *lockstate) 3707 { 3708 SymLook req; 3709 DoneList donelist; 3710 3711 symlook_init(&req, name); 3712 req.lockstate = lockstate; 3713 donelist_init(&donelist); 3714 if (symlook_global(&req, &donelist) != 0) 3715 return (NULL); 3716 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3717 return ((const void **)make_function_pointer(req.sym_out, 3718 req.defobj_out)); 3719 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3720 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3721 else 3722 return ((const void **)(req.defobj_out->relocbase + 3723 req.sym_out->st_value)); 3724 } 3725 3726 /* 3727 * Set a pointer variable in the main program to the given value. This 3728 * is used to set key variables such as "environ" before any of the 3729 * init functions are called. 3730 */ 3731 static void 3732 set_program_var(const char *name, const void *value) 3733 { 3734 const void **addr; 3735 3736 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3737 dbg("\"%s\": *%p <-- %p", name, addr, value); 3738 *addr = value; 3739 } 3740 } 3741 3742 /* 3743 * Search the global objects, including dependencies and main object, 3744 * for the given symbol. 3745 */ 3746 static int 3747 symlook_global(SymLook *req, DoneList *donelist) 3748 { 3749 SymLook req1; 3750 const Objlist_Entry *elm; 3751 int res; 3752 3753 symlook_init_from_req(&req1, req); 3754 3755 /* Search all objects loaded at program start up. */ 3756 if (req->defobj_out == NULL || 3757 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3758 res = symlook_list(&req1, &list_main, donelist); 3759 if (res == 0 && (req->defobj_out == NULL || 3760 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3761 req->sym_out = req1.sym_out; 3762 req->defobj_out = req1.defobj_out; 3763 assert(req->defobj_out != NULL); 3764 } 3765 } 3766 3767 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3768 STAILQ_FOREACH(elm, &list_global, link) { 3769 if (req->defobj_out != NULL && 3770 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3771 break; 3772 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3773 if (res == 0 && (req->defobj_out == NULL || 3774 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3775 req->sym_out = req1.sym_out; 3776 req->defobj_out = req1.defobj_out; 3777 assert(req->defobj_out != NULL); 3778 } 3779 } 3780 3781 return (req->sym_out != NULL ? 0 : ESRCH); 3782 } 3783 3784 /* 3785 * This is a special version of getenv which is far more efficient 3786 * at finding LD_ environment vars. 3787 */ 3788 static 3789 const char * 3790 _getenv_ld(const char *id) 3791 { 3792 const char *envp; 3793 int i, j; 3794 int idlen = strlen(id); 3795 3796 if (ld_index == LD_ARY_CACHE) 3797 return(getenv(id)); 3798 if (ld_index == 0) { 3799 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { 3800 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') 3801 ld_ary[j++] = envp; 3802 } 3803 if (j == 0) 3804 ld_ary[j++] = ""; 3805 ld_index = j; 3806 } 3807 for (i = ld_index - 1; i >= 0; --i) { 3808 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') 3809 return(ld_ary[i] + idlen + 1); 3810 } 3811 return(NULL); 3812 } 3813 3814 /* 3815 * Given a symbol name in a referencing object, find the corresponding 3816 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3817 * no definition was found. Returns a pointer to the Obj_Entry of the 3818 * defining object via the reference parameter DEFOBJ_OUT. 3819 */ 3820 static int 3821 symlook_default(SymLook *req, const Obj_Entry *refobj) 3822 { 3823 DoneList donelist; 3824 const Objlist_Entry *elm; 3825 SymLook req1; 3826 int res; 3827 3828 donelist_init(&donelist); 3829 symlook_init_from_req(&req1, req); 3830 3831 /* Look first in the referencing object if linked symbolically. */ 3832 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3833 res = symlook_obj(&req1, refobj); 3834 if (res == 0) { 3835 req->sym_out = req1.sym_out; 3836 req->defobj_out = req1.defobj_out; 3837 assert(req->defobj_out != NULL); 3838 } 3839 } 3840 3841 symlook_global(req, &donelist); 3842 3843 /* Search all dlopened DAGs containing the referencing object. */ 3844 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3845 if (req->sym_out != NULL && 3846 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3847 break; 3848 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3849 if (res == 0 && (req->sym_out == NULL || 3850 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3851 req->sym_out = req1.sym_out; 3852 req->defobj_out = req1.defobj_out; 3853 assert(req->defobj_out != NULL); 3854 } 3855 } 3856 3857 /* 3858 * Search the dynamic linker itself, and possibly resolve the 3859 * symbol from there. This is how the application links to 3860 * dynamic linker services such as dlopen. 3861 */ 3862 if (req->sym_out == NULL || 3863 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3864 res = symlook_obj(&req1, &obj_rtld); 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 return (req->sym_out != NULL ? 0 : ESRCH); 3873 } 3874 3875 static int 3876 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3877 { 3878 const Elf_Sym *def; 3879 const Obj_Entry *defobj; 3880 const Objlist_Entry *elm; 3881 SymLook req1; 3882 int res; 3883 3884 def = NULL; 3885 defobj = NULL; 3886 STAILQ_FOREACH(elm, objlist, link) { 3887 if (donelist_check(dlp, elm->obj)) 3888 continue; 3889 symlook_init_from_req(&req1, req); 3890 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3891 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3892 def = req1.sym_out; 3893 defobj = req1.defobj_out; 3894 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3895 break; 3896 } 3897 } 3898 } 3899 if (def != NULL) { 3900 req->sym_out = def; 3901 req->defobj_out = defobj; 3902 return (0); 3903 } 3904 return (ESRCH); 3905 } 3906 3907 /* 3908 * Search the chain of DAGS cointed to by the given Needed_Entry 3909 * for a symbol of the given name. Each DAG is scanned completely 3910 * before advancing to the next one. Returns a pointer to the symbol, 3911 * or NULL if no definition was found. 3912 */ 3913 static int 3914 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3915 { 3916 const Elf_Sym *def; 3917 const Needed_Entry *n; 3918 const Obj_Entry *defobj; 3919 SymLook req1; 3920 int res; 3921 3922 def = NULL; 3923 defobj = NULL; 3924 symlook_init_from_req(&req1, req); 3925 for (n = needed; n != NULL; n = n->next) { 3926 if (n->obj == NULL || 3927 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3928 continue; 3929 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3930 def = req1.sym_out; 3931 defobj = req1.defobj_out; 3932 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3933 break; 3934 } 3935 } 3936 if (def != NULL) { 3937 req->sym_out = def; 3938 req->defobj_out = defobj; 3939 return (0); 3940 } 3941 return (ESRCH); 3942 } 3943 3944 /* 3945 * Search the symbol table of a single shared object for a symbol of 3946 * the given name and version, if requested. Returns a pointer to the 3947 * symbol, or NULL if no definition was found. If the object is 3948 * filter, return filtered symbol from filtee. 3949 * 3950 * The symbol's hash value is passed in for efficiency reasons; that 3951 * eliminates many recomputations of the hash value. 3952 */ 3953 int 3954 symlook_obj(SymLook *req, const Obj_Entry *obj) 3955 { 3956 DoneList donelist; 3957 SymLook req1; 3958 int flags, res, mres; 3959 3960 /* 3961 * If there is at least one valid hash at this point, we prefer to 3962 * use the faster GNU version if available. 3963 */ 3964 if (obj->valid_hash_gnu) 3965 mres = symlook_obj1_gnu(req, obj); 3966 else if (obj->valid_hash_sysv) 3967 mres = symlook_obj1_sysv(req, obj); 3968 else 3969 return (EINVAL); 3970 3971 if (mres == 0) { 3972 if (obj->needed_filtees != NULL) { 3973 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3974 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3975 donelist_init(&donelist); 3976 symlook_init_from_req(&req1, req); 3977 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3978 if (res == 0) { 3979 req->sym_out = req1.sym_out; 3980 req->defobj_out = req1.defobj_out; 3981 } 3982 return (res); 3983 } 3984 if (obj->needed_aux_filtees != NULL) { 3985 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3986 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3987 donelist_init(&donelist); 3988 symlook_init_from_req(&req1, req); 3989 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3990 if (res == 0) { 3991 req->sym_out = req1.sym_out; 3992 req->defobj_out = req1.defobj_out; 3993 return (res); 3994 } 3995 } 3996 } 3997 return (mres); 3998 } 3999 4000 /* Symbol match routine common to both hash functions */ 4001 static bool 4002 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 4003 const unsigned long symnum) 4004 { 4005 Elf_Versym verndx; 4006 const Elf_Sym *symp; 4007 const char *strp; 4008 4009 symp = obj->symtab + symnum; 4010 strp = obj->strtab + symp->st_name; 4011 4012 switch (ELF_ST_TYPE(symp->st_info)) { 4013 case STT_FUNC: 4014 case STT_NOTYPE: 4015 case STT_OBJECT: 4016 case STT_COMMON: 4017 case STT_GNU_IFUNC: 4018 if (symp->st_value == 0) 4019 return (false); 4020 /* fallthrough */ 4021 case STT_TLS: 4022 if (symp->st_shndx != SHN_UNDEF) 4023 break; 4024 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4025 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4026 break; 4027 /* fallthrough */ 4028 default: 4029 return (false); 4030 } 4031 if (strcmp(req->name, strp) != 0) 4032 return (false); 4033 4034 if (req->ventry == NULL) { 4035 if (obj->versyms != NULL) { 4036 verndx = VER_NDX(obj->versyms[symnum]); 4037 if (verndx > obj->vernum) { 4038 _rtld_error( 4039 "%s: symbol %s references wrong version %d", 4040 obj->path, obj->strtab + symnum, verndx); 4041 return (false); 4042 } 4043 /* 4044 * If we are not called from dlsym (i.e. this 4045 * is a normal relocation from unversioned 4046 * binary), accept the symbol immediately if 4047 * it happens to have first version after this 4048 * shared object became versioned. Otherwise, 4049 * if symbol is versioned and not hidden, 4050 * remember it. If it is the only symbol with 4051 * this name exported by the shared object, it 4052 * will be returned as a match by the calling 4053 * function. If symbol is global (verndx < 2) 4054 * accept it unconditionally. 4055 */ 4056 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4057 verndx == VER_NDX_GIVEN) { 4058 result->sym_out = symp; 4059 return (true); 4060 } 4061 else if (verndx >= VER_NDX_GIVEN) { 4062 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4063 == 0) { 4064 if (result->vsymp == NULL) 4065 result->vsymp = symp; 4066 result->vcount++; 4067 } 4068 return (false); 4069 } 4070 } 4071 result->sym_out = symp; 4072 return (true); 4073 } 4074 if (obj->versyms == NULL) { 4075 if (object_match_name(obj, req->ventry->name)) { 4076 _rtld_error("%s: object %s should provide version %s " 4077 "for symbol %s", obj_rtld.path, obj->path, 4078 req->ventry->name, obj->strtab + symnum); 4079 return (false); 4080 } 4081 } else { 4082 verndx = VER_NDX(obj->versyms[symnum]); 4083 if (verndx > obj->vernum) { 4084 _rtld_error("%s: symbol %s references wrong version %d", 4085 obj->path, obj->strtab + symnum, verndx); 4086 return (false); 4087 } 4088 if (obj->vertab[verndx].hash != req->ventry->hash || 4089 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4090 /* 4091 * Version does not match. Look if this is a 4092 * global symbol and if it is not hidden. If 4093 * global symbol (verndx < 2) is available, 4094 * use it. Do not return symbol if we are 4095 * called by dlvsym, because dlvsym looks for 4096 * a specific version and default one is not 4097 * what dlvsym wants. 4098 */ 4099 if ((req->flags & SYMLOOK_DLSYM) || 4100 (verndx >= VER_NDX_GIVEN) || 4101 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4102 return (false); 4103 } 4104 } 4105 result->sym_out = symp; 4106 return (true); 4107 } 4108 4109 /* 4110 * Search for symbol using SysV hash function. 4111 * obj->buckets is known not to be NULL at this point; the test for this was 4112 * performed with the obj->valid_hash_sysv assignment. 4113 */ 4114 static int 4115 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4116 { 4117 unsigned long symnum; 4118 Sym_Match_Result matchres; 4119 4120 matchres.sym_out = NULL; 4121 matchres.vsymp = NULL; 4122 matchres.vcount = 0; 4123 4124 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4125 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4126 if (symnum >= obj->nchains) 4127 return (ESRCH); /* Bad object */ 4128 4129 if (matched_symbol(req, obj, &matchres, symnum)) { 4130 req->sym_out = matchres.sym_out; 4131 req->defobj_out = obj; 4132 return (0); 4133 } 4134 } 4135 if (matchres.vcount == 1) { 4136 req->sym_out = matchres.vsymp; 4137 req->defobj_out = obj; 4138 return (0); 4139 } 4140 return (ESRCH); 4141 } 4142 4143 /* Search for symbol using GNU hash function */ 4144 static int 4145 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4146 { 4147 Elf_Addr bloom_word; 4148 const Elf32_Word *hashval; 4149 Elf32_Word bucket; 4150 Sym_Match_Result matchres; 4151 unsigned int h1, h2; 4152 unsigned long symnum; 4153 4154 matchres.sym_out = NULL; 4155 matchres.vsymp = NULL; 4156 matchres.vcount = 0; 4157 4158 /* Pick right bitmask word from Bloom filter array */ 4159 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4160 obj->maskwords_bm_gnu]; 4161 4162 /* Calculate modulus word size of gnu hash and its derivative */ 4163 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4164 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4165 4166 /* Filter out the "definitely not in set" queries */ 4167 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4168 return (ESRCH); 4169 4170 /* Locate hash chain and corresponding value element*/ 4171 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4172 if (bucket == 0) 4173 return (ESRCH); 4174 hashval = &obj->chain_zero_gnu[bucket]; 4175 do { 4176 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4177 symnum = hashval - obj->chain_zero_gnu; 4178 if (matched_symbol(req, obj, &matchres, symnum)) { 4179 req->sym_out = matchres.sym_out; 4180 req->defobj_out = obj; 4181 return (0); 4182 } 4183 } 4184 } while ((*hashval++ & 1) == 0); 4185 if (matchres.vcount == 1) { 4186 req->sym_out = matchres.vsymp; 4187 req->defobj_out = obj; 4188 return (0); 4189 } 4190 return (ESRCH); 4191 } 4192 4193 static void 4194 trace_loaded_objects(Obj_Entry *obj) 4195 { 4196 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4197 int c; 4198 4199 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4200 main_local = ""; 4201 4202 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4203 fmt1 = "\t%o => %p (%x)\n"; 4204 4205 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4206 fmt2 = "\t%o (%x)\n"; 4207 4208 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL"); 4209 4210 for (; obj; obj = obj->next) { 4211 Needed_Entry *needed; 4212 char *name, *path; 4213 bool is_lib; 4214 4215 if (list_containers && obj->needed != NULL) 4216 rtld_printf("%s:\n", obj->path); 4217 for (needed = obj->needed; needed; needed = needed->next) { 4218 if (needed->obj != NULL) { 4219 if (needed->obj->traced && !list_containers) 4220 continue; 4221 needed->obj->traced = true; 4222 path = needed->obj->path; 4223 } else 4224 path = "not found"; 4225 4226 name = (char *)obj->strtab + needed->name; 4227 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4228 4229 fmt = is_lib ? fmt1 : fmt2; 4230 while ((c = *fmt++) != '\0') { 4231 switch (c) { 4232 default: 4233 rtld_putchar(c); 4234 continue; 4235 case '\\': 4236 switch (c = *fmt) { 4237 case '\0': 4238 continue; 4239 case 'n': 4240 rtld_putchar('\n'); 4241 break; 4242 case 't': 4243 rtld_putchar('\t'); 4244 break; 4245 } 4246 break; 4247 case '%': 4248 switch (c = *fmt) { 4249 case '\0': 4250 continue; 4251 case '%': 4252 default: 4253 rtld_putchar(c); 4254 break; 4255 case 'A': 4256 rtld_putstr(main_local); 4257 break; 4258 case 'a': 4259 rtld_putstr(obj_main->path); 4260 break; 4261 case 'o': 4262 rtld_putstr(name); 4263 break; 4264 case 'p': 4265 rtld_putstr(path); 4266 break; 4267 case 'x': 4268 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4269 0); 4270 break; 4271 } 4272 break; 4273 } 4274 ++fmt; 4275 } 4276 } 4277 } 4278 } 4279 4280 /* 4281 * Unload a dlopened object and its dependencies from memory and from 4282 * our data structures. It is assumed that the DAG rooted in the 4283 * object has already been unreferenced, and that the object has a 4284 * reference count of 0. 4285 */ 4286 static void 4287 unload_object(Obj_Entry *root) 4288 { 4289 Obj_Entry *obj; 4290 Obj_Entry **linkp; 4291 4292 assert(root->refcount == 0); 4293 4294 /* 4295 * Pass over the DAG removing unreferenced objects from 4296 * appropriate lists. 4297 */ 4298 unlink_object(root); 4299 4300 /* Unmap all objects that are no longer referenced. */ 4301 linkp = &obj_list->next; 4302 while ((obj = *linkp) != NULL) { 4303 if (obj->refcount == 0) { 4304 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4305 obj->path); 4306 dbg("unloading \"%s\"", obj->path); 4307 unload_filtees(root); 4308 munmap(obj->mapbase, obj->mapsize); 4309 linkmap_delete(obj); 4310 *linkp = obj->next; 4311 obj_count--; 4312 obj_free(obj); 4313 } else 4314 linkp = &obj->next; 4315 } 4316 obj_tail = linkp; 4317 } 4318 4319 static void 4320 unlink_object(Obj_Entry *root) 4321 { 4322 Objlist_Entry *elm; 4323 4324 if (root->refcount == 0) { 4325 /* Remove the object from the RTLD_GLOBAL list. */ 4326 objlist_remove(&list_global, root); 4327 4328 /* Remove the object from all objects' DAG lists. */ 4329 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4330 objlist_remove(&elm->obj->dldags, root); 4331 if (elm->obj != root) 4332 unlink_object(elm->obj); 4333 } 4334 } 4335 } 4336 4337 static void 4338 ref_dag(Obj_Entry *root) 4339 { 4340 Objlist_Entry *elm; 4341 4342 assert(root->dag_inited); 4343 STAILQ_FOREACH(elm, &root->dagmembers, link) 4344 elm->obj->refcount++; 4345 } 4346 4347 static void 4348 unref_dag(Obj_Entry *root) 4349 { 4350 Objlist_Entry *elm; 4351 4352 assert(root->dag_inited); 4353 STAILQ_FOREACH(elm, &root->dagmembers, link) 4354 elm->obj->refcount--; 4355 } 4356 4357 /* 4358 * Common code for MD __tls_get_addr(). 4359 */ 4360 void * 4361 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset) 4362 { 4363 Elf_Addr* dtv = *dtvp; 4364 RtldLockState lockstate; 4365 4366 /* Check dtv generation in case new modules have arrived */ 4367 if (dtv[0] != tls_dtv_generation) { 4368 Elf_Addr* newdtv; 4369 int to_copy; 4370 4371 wlock_acquire(rtld_bind_lock, &lockstate); 4372 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4373 to_copy = dtv[1]; 4374 if (to_copy > tls_max_index) 4375 to_copy = tls_max_index; 4376 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4377 newdtv[0] = tls_dtv_generation; 4378 newdtv[1] = tls_max_index; 4379 free(dtv); 4380 lock_release(rtld_bind_lock, &lockstate); 4381 dtv = *dtvp = newdtv; 4382 } 4383 4384 /* Dynamically allocate module TLS if necessary */ 4385 if (!dtv[index + 1]) { 4386 /* Signal safe, wlock will block out signals. */ 4387 wlock_acquire(rtld_bind_lock, &lockstate); 4388 if (!dtv[index + 1]) 4389 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4390 lock_release(rtld_bind_lock, &lockstate); 4391 } 4392 return ((void *)(dtv[index + 1] + offset)); 4393 } 4394 4395 #if defined(RTLD_STATIC_TLS_VARIANT_II) 4396 4397 /* 4398 * Allocate the static TLS area. Return a pointer to the TCB. The 4399 * static area is based on negative offsets relative to the tcb. 4400 * 4401 * The TCB contains an errno pointer for the system call layer, but because 4402 * we are the RTLD we really have no idea how the caller was compiled so 4403 * the information has to be passed in. errno can either be: 4404 * 4405 * type 0 errno is a simple non-TLS global pointer. 4406 * (special case for e.g. libc_rtld) 4407 * type 1 errno accessed by GOT entry (dynamically linked programs) 4408 * type 2 errno accessed by %gs:OFFSET (statically linked programs) 4409 */ 4410 struct tls_tcb * 4411 allocate_tls(Obj_Entry *objs) 4412 { 4413 Obj_Entry *obj; 4414 size_t data_size; 4415 size_t dtv_size; 4416 struct tls_tcb *tcb; 4417 Elf_Addr *dtv; 4418 Elf_Addr addr; 4419 4420 /* 4421 * Allocate the new TCB. static TLS storage is placed just before the 4422 * TCB to support the %gs:OFFSET (negative offset) model. 4423 */ 4424 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4425 ~RTLD_STATIC_TLS_ALIGN_MASK; 4426 tcb = malloc(data_size + sizeof(*tcb)); 4427 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ 4428 4429 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); 4430 dtv = malloc(dtv_size); 4431 bzero(dtv, dtv_size); 4432 4433 #ifdef RTLD_TCB_HAS_SELF_POINTER 4434 tcb->tcb_self = tcb; 4435 #endif 4436 tcb->tcb_dtv = dtv; 4437 tcb->tcb_pthread = NULL; 4438 4439 dtv[0] = tls_dtv_generation; 4440 dtv[1] = tls_max_index; 4441 4442 for (obj = objs; obj; obj = obj->next) { 4443 if (obj->tlsoffset) { 4444 addr = (Elf_Addr)tcb - obj->tlsoffset; 4445 memset((void *)(addr + obj->tlsinitsize), 4446 0, obj->tlssize - obj->tlsinitsize); 4447 if (obj->tlsinit) 4448 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4449 dtv[obj->tlsindex + 1] = addr; 4450 } 4451 } 4452 return(tcb); 4453 } 4454 4455 void 4456 free_tls(struct tls_tcb *tcb) 4457 { 4458 Elf_Addr *dtv; 4459 int dtv_size, i; 4460 Elf_Addr tls_start, tls_end; 4461 size_t data_size; 4462 4463 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & 4464 ~RTLD_STATIC_TLS_ALIGN_MASK; 4465 4466 dtv = tcb->tcb_dtv; 4467 dtv_size = dtv[1]; 4468 tls_end = (Elf_Addr)tcb; 4469 tls_start = (Elf_Addr)tcb - data_size; 4470 for (i = 0; i < dtv_size; i++) { 4471 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { 4472 free((void *)dtv[i+2]); 4473 } 4474 } 4475 free(dtv); 4476 4477 free((void*) tls_start); 4478 } 4479 4480 #else 4481 #error "Unsupported TLS layout" 4482 #endif 4483 4484 /* 4485 * Allocate TLS block for module with given index. 4486 */ 4487 void * 4488 allocate_module_tls(int index) 4489 { 4490 Obj_Entry* obj; 4491 char* p; 4492 4493 for (obj = obj_list; obj; obj = obj->next) { 4494 if (obj->tlsindex == index) 4495 break; 4496 } 4497 if (!obj) { 4498 _rtld_error("Can't find module with TLS index %d", index); 4499 die(); 4500 } 4501 4502 p = malloc(obj->tlssize); 4503 if (p == NULL) { 4504 _rtld_error("Cannot allocate TLS block for index %d", index); 4505 die(); 4506 } 4507 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4508 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4509 4510 return p; 4511 } 4512 4513 bool 4514 allocate_tls_offset(Obj_Entry *obj) 4515 { 4516 size_t off; 4517 4518 if (obj->tls_done) 4519 return true; 4520 4521 if (obj->tlssize == 0) { 4522 obj->tls_done = true; 4523 return true; 4524 } 4525 4526 if (obj->tlsindex == 1) 4527 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4528 else 4529 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4530 obj->tlssize, obj->tlsalign); 4531 4532 /* 4533 * If we have already fixed the size of the static TLS block, we 4534 * must stay within that size. When allocating the static TLS, we 4535 * leave a small amount of space spare to be used for dynamically 4536 * loading modules which use static TLS. 4537 */ 4538 if (tls_static_space) { 4539 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4540 return false; 4541 } 4542 4543 tls_last_offset = obj->tlsoffset = off; 4544 tls_last_size = obj->tlssize; 4545 obj->tls_done = true; 4546 4547 return true; 4548 } 4549 4550 void 4551 free_tls_offset(Obj_Entry *obj) 4552 { 4553 #ifdef RTLD_STATIC_TLS_VARIANT_II 4554 /* 4555 * If we were the last thing to allocate out of the static TLS 4556 * block, we give our space back to the 'allocator'. This is a 4557 * simplistic workaround to allow libGL.so.1 to be loaded and 4558 * unloaded multiple times. We only handle the Variant II 4559 * mechanism for now - this really needs a proper allocator. 4560 */ 4561 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4562 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4563 tls_last_offset -= obj->tlssize; 4564 tls_last_size = 0; 4565 } 4566 #endif 4567 } 4568 4569 struct tls_tcb * 4570 _rtld_allocate_tls(void) 4571 { 4572 struct tls_tcb *new_tcb; 4573 RtldLockState lockstate; 4574 4575 wlock_acquire(rtld_bind_lock, &lockstate); 4576 new_tcb = allocate_tls(obj_list); 4577 lock_release(rtld_bind_lock, &lockstate); 4578 return (new_tcb); 4579 } 4580 4581 void 4582 _rtld_free_tls(struct tls_tcb *tcb) 4583 { 4584 RtldLockState lockstate; 4585 4586 wlock_acquire(rtld_bind_lock, &lockstate); 4587 free_tls(tcb); 4588 lock_release(rtld_bind_lock, &lockstate); 4589 } 4590 4591 static void 4592 object_add_name(Obj_Entry *obj, const char *name) 4593 { 4594 Name_Entry *entry; 4595 size_t len; 4596 4597 len = strlen(name); 4598 entry = malloc(sizeof(Name_Entry) + len); 4599 4600 if (entry != NULL) { 4601 strcpy(entry->name, name); 4602 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4603 } 4604 } 4605 4606 static int 4607 object_match_name(const Obj_Entry *obj, const char *name) 4608 { 4609 Name_Entry *entry; 4610 4611 STAILQ_FOREACH(entry, &obj->names, link) { 4612 if (strcmp(name, entry->name) == 0) 4613 return (1); 4614 } 4615 return (0); 4616 } 4617 4618 static Obj_Entry * 4619 locate_dependency(const Obj_Entry *obj, const char *name) 4620 { 4621 const Objlist_Entry *entry; 4622 const Needed_Entry *needed; 4623 4624 STAILQ_FOREACH(entry, &list_main, link) { 4625 if (object_match_name(entry->obj, name)) 4626 return entry->obj; 4627 } 4628 4629 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4630 if (strcmp(obj->strtab + needed->name, name) == 0 || 4631 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4632 /* 4633 * If there is DT_NEEDED for the name we are looking for, 4634 * we are all set. Note that object might not be found if 4635 * dependency was not loaded yet, so the function can 4636 * return NULL here. This is expected and handled 4637 * properly by the caller. 4638 */ 4639 return (needed->obj); 4640 } 4641 } 4642 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4643 obj->path, name); 4644 die(); 4645 } 4646 4647 static int 4648 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4649 const Elf_Vernaux *vna) 4650 { 4651 const Elf_Verdef *vd; 4652 const char *vername; 4653 4654 vername = refobj->strtab + vna->vna_name; 4655 vd = depobj->verdef; 4656 if (vd == NULL) { 4657 _rtld_error("%s: version %s required by %s not defined", 4658 depobj->path, vername, refobj->path); 4659 return (-1); 4660 } 4661 for (;;) { 4662 if (vd->vd_version != VER_DEF_CURRENT) { 4663 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4664 depobj->path, vd->vd_version); 4665 return (-1); 4666 } 4667 if (vna->vna_hash == vd->vd_hash) { 4668 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4669 ((char *)vd + vd->vd_aux); 4670 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4671 return (0); 4672 } 4673 if (vd->vd_next == 0) 4674 break; 4675 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4676 } 4677 if (vna->vna_flags & VER_FLG_WEAK) 4678 return (0); 4679 _rtld_error("%s: version %s required by %s not found", 4680 depobj->path, vername, refobj->path); 4681 return (-1); 4682 } 4683 4684 static int 4685 rtld_verify_object_versions(Obj_Entry *obj) 4686 { 4687 const Elf_Verneed *vn; 4688 const Elf_Verdef *vd; 4689 const Elf_Verdaux *vda; 4690 const Elf_Vernaux *vna; 4691 const Obj_Entry *depobj; 4692 int maxvernum, vernum; 4693 4694 if (obj->ver_checked) 4695 return (0); 4696 obj->ver_checked = true; 4697 4698 maxvernum = 0; 4699 /* 4700 * Walk over defined and required version records and figure out 4701 * max index used by any of them. Do very basic sanity checking 4702 * while there. 4703 */ 4704 vn = obj->verneed; 4705 while (vn != NULL) { 4706 if (vn->vn_version != VER_NEED_CURRENT) { 4707 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4708 obj->path, vn->vn_version); 4709 return (-1); 4710 } 4711 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4712 for (;;) { 4713 vernum = VER_NEED_IDX(vna->vna_other); 4714 if (vernum > maxvernum) 4715 maxvernum = vernum; 4716 if (vna->vna_next == 0) 4717 break; 4718 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4719 } 4720 if (vn->vn_next == 0) 4721 break; 4722 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4723 } 4724 4725 vd = obj->verdef; 4726 while (vd != NULL) { 4727 if (vd->vd_version != VER_DEF_CURRENT) { 4728 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4729 obj->path, vd->vd_version); 4730 return (-1); 4731 } 4732 vernum = VER_DEF_IDX(vd->vd_ndx); 4733 if (vernum > maxvernum) 4734 maxvernum = vernum; 4735 if (vd->vd_next == 0) 4736 break; 4737 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4738 } 4739 4740 if (maxvernum == 0) 4741 return (0); 4742 4743 /* 4744 * Store version information in array indexable by version index. 4745 * Verify that object version requirements are satisfied along the 4746 * way. 4747 */ 4748 obj->vernum = maxvernum + 1; 4749 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4750 4751 vd = obj->verdef; 4752 while (vd != NULL) { 4753 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4754 vernum = VER_DEF_IDX(vd->vd_ndx); 4755 assert(vernum <= maxvernum); 4756 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4757 obj->vertab[vernum].hash = vd->vd_hash; 4758 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4759 obj->vertab[vernum].file = NULL; 4760 obj->vertab[vernum].flags = 0; 4761 } 4762 if (vd->vd_next == 0) 4763 break; 4764 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4765 } 4766 4767 vn = obj->verneed; 4768 while (vn != NULL) { 4769 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4770 if (depobj == NULL) 4771 return (-1); 4772 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4773 for (;;) { 4774 if (check_object_provided_version(obj, depobj, vna)) 4775 return (-1); 4776 vernum = VER_NEED_IDX(vna->vna_other); 4777 assert(vernum <= maxvernum); 4778 obj->vertab[vernum].hash = vna->vna_hash; 4779 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4780 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4781 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4782 VER_INFO_HIDDEN : 0; 4783 if (vna->vna_next == 0) 4784 break; 4785 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4786 } 4787 if (vn->vn_next == 0) 4788 break; 4789 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4790 } 4791 return 0; 4792 } 4793 4794 static int 4795 rtld_verify_versions(const Objlist *objlist) 4796 { 4797 Objlist_Entry *entry; 4798 int rc; 4799 4800 rc = 0; 4801 STAILQ_FOREACH(entry, objlist, link) { 4802 /* 4803 * Skip dummy objects or objects that have their version requirements 4804 * already checked. 4805 */ 4806 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4807 continue; 4808 if (rtld_verify_object_versions(entry->obj) == -1) { 4809 rc = -1; 4810 if (ld_tracing == NULL) 4811 break; 4812 } 4813 } 4814 if (rc == 0 || ld_tracing != NULL) 4815 rc = rtld_verify_object_versions(&obj_rtld); 4816 return rc; 4817 } 4818 4819 const Ver_Entry * 4820 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4821 { 4822 Elf_Versym vernum; 4823 4824 if (obj->vertab) { 4825 vernum = VER_NDX(obj->versyms[symnum]); 4826 if (vernum >= obj->vernum) { 4827 _rtld_error("%s: symbol %s has wrong verneed value %d", 4828 obj->path, obj->strtab + symnum, vernum); 4829 } else if (obj->vertab[vernum].hash != 0) { 4830 return &obj->vertab[vernum]; 4831 } 4832 } 4833 return NULL; 4834 } 4835 4836 int 4837 _rtld_get_stack_prot(void) 4838 { 4839 4840 return (stack_prot); 4841 } 4842 4843 static void 4844 map_stacks_exec(RtldLockState *lockstate) 4845 { 4846 return; 4847 /* 4848 * Stack protection must be implemented in the kernel before the dynamic 4849 * linker can handle PT_GNU_STACK sections. 4850 * The following is the FreeBSD implementation of map_stacks_exec() 4851 * void (*thr_map_stacks_exec)(void); 4852 * 4853 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4854 * return; 4855 * thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4856 * get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4857 * if (thr_map_stacks_exec != NULL) { 4858 * stack_prot |= PROT_EXEC; 4859 * thr_map_stacks_exec(); 4860 * } 4861 */ 4862 } 4863 4864 void 4865 symlook_init(SymLook *dst, const char *name) 4866 { 4867 4868 bzero(dst, sizeof(*dst)); 4869 dst->name = name; 4870 dst->hash = elf_hash(name); 4871 dst->hash_gnu = gnu_hash(name); 4872 } 4873 4874 static void 4875 symlook_init_from_req(SymLook *dst, const SymLook *src) 4876 { 4877 4878 dst->name = src->name; 4879 dst->hash = src->hash; 4880 dst->hash_gnu = src->hash_gnu; 4881 dst->ventry = src->ventry; 4882 dst->flags = src->flags; 4883 dst->defobj_out = NULL; 4884 dst->sym_out = NULL; 4885 dst->lockstate = src->lockstate; 4886 } 4887 4888 4889 /* 4890 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4891 */ 4892 static int 4893 parse_libdir(const char *str) 4894 { 4895 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4896 const char *orig; 4897 int fd; 4898 char c; 4899 4900 orig = str; 4901 fd = 0; 4902 for (c = *str; c != '\0'; c = *++str) { 4903 if (c < '0' || c > '9') 4904 return (-1); 4905 4906 fd *= RADIX; 4907 fd += c - '0'; 4908 } 4909 4910 /* Make sure we actually parsed something. */ 4911 if (str == orig) { 4912 _rtld_error("failed to parse directory FD from '%s'", str); 4913 return (-1); 4914 } 4915 return (fd); 4916 } 4917 4918 #ifdef ENABLE_OSRELDATE 4919 /* 4920 * Overrides for libc_pic-provided functions. 4921 */ 4922 4923 int 4924 __getosreldate(void) 4925 { 4926 size_t len; 4927 int oid[2]; 4928 int error, osrel; 4929 4930 if (osreldate != 0) 4931 return (osreldate); 4932 4933 oid[0] = CTL_KERN; 4934 oid[1] = KERN_OSRELDATE; 4935 osrel = 0; 4936 len = sizeof(osrel); 4937 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 4938 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 4939 osreldate = osrel; 4940 return (osreldate); 4941 } 4942 #endif 4943 4944 /* 4945 * No unresolved symbols for rtld. 4946 */ 4947 void 4948 __pthread_cxa_finalize(struct dl_phdr_info *a) 4949 { 4950 } 4951 4952 const char * 4953 rtld_strerror(int errnum) 4954 { 4955 4956 if (errnum < 0 || errnum >= sys_nerr) 4957 return ("Unknown error"); 4958 return (sys_errlist[errnum]); 4959 } 4960