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 #include <sys/param.h> 38 #include <sys/mount.h> 39 #include <sys/mman.h> 40 #include <sys/stat.h> 41 #include <sys/sysctl.h> 42 #include <sys/uio.h> 43 #include <sys/utsname.h> 44 #include <sys/ktrace.h> 45 46 #include <dlfcn.h> 47 #include <err.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <stdarg.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 56 #include "debug.h" 57 #include "rtld.h" 58 #include "libmap.h" 59 #include "rtld_tls.h" 60 #include "rtld_printf.h" 61 #include "notes.h" 62 63 #ifndef COMPAT_32BIT 64 #define PATH_RTLD "/libexec/ld-elf.so.1" 65 #else 66 #define PATH_RTLD "/libexec/ld-elf32.so.1" 67 #endif 68 69 /* Types. */ 70 typedef void (*func_ptr_type)(); 71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 72 73 /* 74 * Function declarations. 75 */ 76 static const char *basename(const char *); 77 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 78 const Elf_Dyn **, const Elf_Dyn **); 79 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 80 const Elf_Dyn *); 81 static void digest_dynamic(Obj_Entry *, int); 82 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 83 static Obj_Entry *dlcheck(void *); 84 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 85 int lo_flags, int mode, RtldLockState *lockstate); 86 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 87 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 88 static bool donelist_check(DoneList *, const Obj_Entry *); 89 static void errmsg_restore(char *); 90 static char *errmsg_save(void); 91 static void *fill_search_info(const char *, size_t, void *); 92 static char *find_library(const char *, const Obj_Entry *, int *); 93 static const char *gethints(bool); 94 static void init_dag(Obj_Entry *); 95 static void init_pagesizes(Elf_Auxinfo **aux_info); 96 static void init_rtld(caddr_t, Elf_Auxinfo **); 97 static void initlist_add_neededs(Needed_Entry *, Objlist *); 98 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 99 static void linkmap_add(Obj_Entry *); 100 static void linkmap_delete(Obj_Entry *); 101 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 102 static void unload_filtees(Obj_Entry *); 103 static int load_needed_objects(Obj_Entry *, int); 104 static int load_preload_objects(void); 105 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 106 static void map_stacks_exec(RtldLockState *); 107 static Obj_Entry *obj_from_addr(const void *); 108 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 109 static void objlist_call_init(Objlist *, RtldLockState *); 110 static void objlist_clear(Objlist *); 111 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 112 static void objlist_init(Objlist *); 113 static void objlist_push_head(Objlist *, Obj_Entry *); 114 static void objlist_push_tail(Objlist *, Obj_Entry *); 115 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 116 static void objlist_remove(Objlist *, Obj_Entry *); 117 static int parse_libdir(const char *); 118 static void *path_enumerate(const char *, path_enum_proc, void *); 119 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 120 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 121 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 122 int flags, RtldLockState *lockstate); 123 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 124 RtldLockState *); 125 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 126 int flags, RtldLockState *lockstate); 127 static int rtld_dirname(const char *, char *); 128 static int rtld_dirname_abs(const char *, char *); 129 static void *rtld_dlopen(const char *name, int fd, int mode); 130 static void rtld_exit(void); 131 static char *search_library_path(const char *, const char *); 132 static char *search_library_pathfds(const char *, const char *, int *); 133 static const void **get_program_var_addr(const char *, RtldLockState *); 134 static void set_program_var(const char *, const void *); 135 static int symlook_default(SymLook *, const Obj_Entry *refobj); 136 static int symlook_global(SymLook *, DoneList *); 137 static void symlook_init_from_req(SymLook *, const SymLook *); 138 static int symlook_list(SymLook *, const Objlist *, DoneList *); 139 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 140 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 141 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 142 static void trace_loaded_objects(Obj_Entry *); 143 static void unlink_object(Obj_Entry *); 144 static void unload_object(Obj_Entry *); 145 static void unref_dag(Obj_Entry *); 146 static void ref_dag(Obj_Entry *); 147 static char *origin_subst_one(Obj_Entry *, char *, const char *, 148 const char *, bool); 149 static char *origin_subst(Obj_Entry *, char *); 150 static bool obj_resolve_origin(Obj_Entry *obj); 151 static void preinit_main(void); 152 static int rtld_verify_versions(const Objlist *); 153 static int rtld_verify_object_versions(Obj_Entry *); 154 static void object_add_name(Obj_Entry *, const char *); 155 static int object_match_name(const Obj_Entry *, const char *); 156 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 157 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 158 struct dl_phdr_info *phdr_info); 159 static uint32_t gnu_hash(const char *); 160 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 161 const unsigned long); 162 163 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 164 void _r_debug_postinit(struct link_map *) __noinline __exported; 165 166 int __sys_openat(int, const char *, int, ...); 167 168 /* 169 * Data declarations. 170 */ 171 static char *error_message; /* Message for dlerror(), or NULL */ 172 struct r_debug r_debug __exported; /* 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 char *ld_bind_now; /* Environment variable for immediate binding */ 180 static char *ld_debug; /* Environment variable for debugging */ 181 static char *ld_library_path; /* Environment variable for search path */ 182 static char *ld_library_dirs; /* Environment variable for library descriptors */ 183 static char *ld_preload; /* Environment variable for libraries to 184 load first */ 185 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 186 static char *ld_tracing; /* Called from ldd to print libs */ 187 static char *ld_utrace; /* Use utrace() to log events. */ 188 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 189 static Obj_Entry **obj_tail; /* Link field of last object in list */ 190 static Obj_Entry *obj_main; /* The main program shared object */ 191 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 192 static unsigned int obj_count; /* Number of objects in obj_list */ 193 static unsigned int obj_loads; /* Number of objects in obj_list */ 194 195 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 196 STAILQ_HEAD_INITIALIZER(list_global); 197 static Objlist list_main = /* Objects loaded at program startup */ 198 STAILQ_HEAD_INITIALIZER(list_main); 199 static Objlist list_fini = /* Objects needing fini() calls */ 200 STAILQ_HEAD_INITIALIZER(list_fini); 201 202 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 203 204 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 205 206 extern Elf_Dyn _DYNAMIC; 207 #pragma weak _DYNAMIC 208 #ifndef RTLD_IS_DYNAMIC 209 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 210 #endif 211 212 int dlclose(void *) __exported; 213 char *dlerror(void) __exported; 214 void *dlopen(const char *, int) __exported; 215 void *fdlopen(int, int) __exported; 216 void *dlsym(void *, const char *) __exported; 217 dlfunc_t dlfunc(void *, const char *) __exported; 218 void *dlvsym(void *, const char *, const char *) __exported; 219 int dladdr(const void *, Dl_info *) __exported; 220 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 221 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 222 int dlinfo(void *, int , void *) __exported; 223 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 224 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 225 int _rtld_get_stack_prot(void) __exported; 226 int _rtld_is_dlopened(void *) __exported; 227 void _rtld_error(const char *, ...) __exported; 228 229 int npagesizes, osreldate; 230 size_t *pagesizes; 231 232 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 233 234 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 235 static int max_stack_flags; 236 237 /* 238 * Global declarations normally provided by crt1. The dynamic linker is 239 * not built with crt1, so we have to provide them ourselves. 240 */ 241 char *__progname; 242 char **environ; 243 244 /* 245 * Used to pass argc, argv to init functions. 246 */ 247 int main_argc; 248 char **main_argv; 249 250 /* 251 * Globals to control TLS allocation. 252 */ 253 size_t tls_last_offset; /* Static TLS offset of last module */ 254 size_t tls_last_size; /* Static TLS size of last module */ 255 size_t tls_static_space; /* Static TLS space allocated */ 256 size_t tls_static_max_align; 257 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 258 int tls_max_index = 1; /* Largest module index allocated */ 259 260 bool ld_library_path_rpath = false; 261 262 /* 263 * Fill in a DoneList with an allocation large enough to hold all of 264 * the currently-loaded objects. Keep this as a macro since it calls 265 * alloca and we want that to occur within the scope of the caller. 266 */ 267 #define donelist_init(dlp) \ 268 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 269 assert((dlp)->objs != NULL), \ 270 (dlp)->num_alloc = obj_count, \ 271 (dlp)->num_used = 0) 272 273 #define UTRACE_DLOPEN_START 1 274 #define UTRACE_DLOPEN_STOP 2 275 #define UTRACE_DLCLOSE_START 3 276 #define UTRACE_DLCLOSE_STOP 4 277 #define UTRACE_LOAD_OBJECT 5 278 #define UTRACE_UNLOAD_OBJECT 6 279 #define UTRACE_ADD_RUNDEP 7 280 #define UTRACE_PRELOAD_FINISHED 8 281 #define UTRACE_INIT_CALL 9 282 #define UTRACE_FINI_CALL 10 283 #define UTRACE_DLSYM_START 11 284 #define UTRACE_DLSYM_STOP 12 285 286 struct utrace_rtld { 287 char sig[4]; /* 'RTLD' */ 288 int event; 289 void *handle; 290 void *mapbase; /* Used for 'parent' and 'init/fini' */ 291 size_t mapsize; 292 int refcnt; /* Used for 'mode' */ 293 char name[MAXPATHLEN]; 294 }; 295 296 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 297 if (ld_utrace != NULL) \ 298 ld_utrace_log(e, h, mb, ms, r, n); \ 299 } while (0) 300 301 static void 302 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 303 int refcnt, const char *name) 304 { 305 struct utrace_rtld ut; 306 307 ut.sig[0] = 'R'; 308 ut.sig[1] = 'T'; 309 ut.sig[2] = 'L'; 310 ut.sig[3] = 'D'; 311 ut.event = event; 312 ut.handle = handle; 313 ut.mapbase = mapbase; 314 ut.mapsize = mapsize; 315 ut.refcnt = refcnt; 316 bzero(ut.name, sizeof(ut.name)); 317 if (name) 318 strlcpy(ut.name, name, sizeof(ut.name)); 319 utrace(&ut, sizeof(ut)); 320 } 321 322 /* 323 * Main entry point for dynamic linking. The first argument is the 324 * stack pointer. The stack is expected to be laid out as described 325 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 326 * Specifically, the stack pointer points to a word containing 327 * ARGC. Following that in the stack is a null-terminated sequence 328 * of pointers to argument strings. Then comes a null-terminated 329 * sequence of pointers to environment strings. Finally, there is a 330 * sequence of "auxiliary vector" entries. 331 * 332 * The second argument points to a place to store the dynamic linker's 333 * exit procedure pointer and the third to a place to store the main 334 * program's object. 335 * 336 * The return value is the main program's entry point. 337 */ 338 func_ptr_type 339 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 340 { 341 Elf_Auxinfo *aux_info[AT_COUNT]; 342 int i; 343 int argc; 344 char **argv; 345 char **env; 346 Elf_Auxinfo *aux; 347 Elf_Auxinfo *auxp; 348 const char *argv0; 349 Objlist_Entry *entry; 350 Obj_Entry *obj; 351 Obj_Entry **preload_tail; 352 Obj_Entry *last_interposer; 353 Objlist initlist; 354 RtldLockState lockstate; 355 char *library_path_rpath; 356 int mib[2]; 357 size_t len; 358 359 /* 360 * On entry, the dynamic linker itself has not been relocated yet. 361 * Be very careful not to reference any global data until after 362 * init_rtld has returned. It is OK to reference file-scope statics 363 * and string constants, and to call static and global functions. 364 */ 365 366 /* Find the auxiliary vector on the stack. */ 367 argc = *sp++; 368 argv = (char **) sp; 369 sp += argc + 1; /* Skip over arguments and NULL terminator */ 370 env = (char **) sp; 371 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 372 ; 373 aux = (Elf_Auxinfo *) sp; 374 375 /* Digest the auxiliary vector. */ 376 for (i = 0; i < AT_COUNT; i++) 377 aux_info[i] = NULL; 378 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 379 if (auxp->a_type < AT_COUNT) 380 aux_info[auxp->a_type] = auxp; 381 } 382 383 /* Initialize and relocate ourselves. */ 384 assert(aux_info[AT_BASE] != NULL); 385 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 386 387 __progname = obj_rtld.path; 388 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 389 environ = env; 390 main_argc = argc; 391 main_argv = argv; 392 393 if (aux_info[AT_CANARY] != NULL && 394 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 395 i = aux_info[AT_CANARYLEN]->a_un.a_val; 396 if (i > sizeof(__stack_chk_guard)) 397 i = sizeof(__stack_chk_guard); 398 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 399 } else { 400 mib[0] = CTL_KERN; 401 mib[1] = KERN_ARND; 402 403 len = sizeof(__stack_chk_guard); 404 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 405 len != sizeof(__stack_chk_guard)) { 406 /* If sysctl was unsuccessful, use the "terminator canary". */ 407 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 408 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 409 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 410 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 411 } 412 } 413 414 trust = !issetugid(); 415 416 ld_bind_now = getenv(LD_ "BIND_NOW"); 417 /* 418 * If the process is tainted, then we un-set the dangerous environment 419 * variables. The process will be marked as tainted until setuid(2) 420 * is called. If any child process calls setuid(2) we do not want any 421 * future processes to honor the potentially un-safe variables. 422 */ 423 if (!trust) { 424 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 425 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") || 426 unsetenv(LD_ "LIBMAP_DISABLE") || 427 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 428 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 429 _rtld_error("environment corrupt; aborting"); 430 rtld_die(); 431 } 432 } 433 ld_debug = getenv(LD_ "DEBUG"); 434 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 435 libmap_override = getenv(LD_ "LIBMAP"); 436 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 437 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS"); 438 ld_preload = getenv(LD_ "PRELOAD"); 439 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 440 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 441 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 442 if (library_path_rpath != NULL) { 443 if (library_path_rpath[0] == 'y' || 444 library_path_rpath[0] == 'Y' || 445 library_path_rpath[0] == '1') 446 ld_library_path_rpath = true; 447 else 448 ld_library_path_rpath = false; 449 } 450 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 451 (ld_library_path != NULL) || (ld_preload != NULL) || 452 (ld_elf_hints_path != NULL) || ld_loadfltr; 453 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 454 ld_utrace = getenv(LD_ "UTRACE"); 455 456 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 457 ld_elf_hints_path = _PATH_ELF_HINTS; 458 459 if (ld_debug != NULL && *ld_debug != '\0') 460 debug = 1; 461 dbg("%s is initialized, base address = %p", __progname, 462 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 463 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 464 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 465 466 dbg("initializing thread locks"); 467 lockdflt_init(); 468 469 /* 470 * Load the main program, or process its program header if it is 471 * already loaded. 472 */ 473 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 474 int fd = aux_info[AT_EXECFD]->a_un.a_val; 475 dbg("loading main program"); 476 obj_main = map_object(fd, argv0, NULL); 477 close(fd); 478 if (obj_main == NULL) 479 rtld_die(); 480 max_stack_flags = obj->stack_flags; 481 } else { /* Main program already loaded. */ 482 const Elf_Phdr *phdr; 483 int phnum; 484 caddr_t entry; 485 486 dbg("processing main program's program header"); 487 assert(aux_info[AT_PHDR] != NULL); 488 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 489 assert(aux_info[AT_PHNUM] != NULL); 490 phnum = aux_info[AT_PHNUM]->a_un.a_val; 491 assert(aux_info[AT_PHENT] != NULL); 492 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 493 assert(aux_info[AT_ENTRY] != NULL); 494 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 495 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 496 rtld_die(); 497 } 498 499 if (aux_info[AT_EXECPATH] != 0) { 500 char *kexecpath; 501 char buf[MAXPATHLEN]; 502 503 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 504 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 505 if (kexecpath[0] == '/') 506 obj_main->path = kexecpath; 507 else if (getcwd(buf, sizeof(buf)) == NULL || 508 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 509 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 510 obj_main->path = xstrdup(argv0); 511 else 512 obj_main->path = xstrdup(buf); 513 } else { 514 dbg("No AT_EXECPATH"); 515 obj_main->path = xstrdup(argv0); 516 } 517 dbg("obj_main path %s", obj_main->path); 518 obj_main->mainprog = true; 519 520 if (aux_info[AT_STACKPROT] != NULL && 521 aux_info[AT_STACKPROT]->a_un.a_val != 0) 522 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 523 524 #ifndef COMPAT_32BIT 525 /* 526 * Get the actual dynamic linker pathname from the executable if 527 * possible. (It should always be possible.) That ensures that 528 * gdb will find the right dynamic linker even if a non-standard 529 * one is being used. 530 */ 531 if (obj_main->interp != NULL && 532 strcmp(obj_main->interp, obj_rtld.path) != 0) { 533 free(obj_rtld.path); 534 obj_rtld.path = xstrdup(obj_main->interp); 535 __progname = obj_rtld.path; 536 } 537 #endif 538 539 digest_dynamic(obj_main, 0); 540 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 541 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 542 obj_main->dynsymcount); 543 544 linkmap_add(obj_main); 545 linkmap_add(&obj_rtld); 546 547 /* Link the main program into the list of objects. */ 548 *obj_tail = obj_main; 549 obj_tail = &obj_main->next; 550 obj_count++; 551 obj_loads++; 552 553 /* Initialize a fake symbol for resolving undefined weak references. */ 554 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 555 sym_zero.st_shndx = SHN_UNDEF; 556 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 557 558 if (!libmap_disable) 559 libmap_disable = (bool)lm_init(libmap_override); 560 561 dbg("loading LD_PRELOAD libraries"); 562 if (load_preload_objects() == -1) 563 rtld_die(); 564 preload_tail = obj_tail; 565 566 dbg("loading needed objects"); 567 if (load_needed_objects(obj_main, 0) == -1) 568 rtld_die(); 569 570 /* Make a list of all objects loaded at startup. */ 571 last_interposer = obj_main; 572 for (obj = obj_list; obj != NULL; obj = obj->next) { 573 if (obj->z_interpose && obj != obj_main) { 574 objlist_put_after(&list_main, last_interposer, obj); 575 last_interposer = obj; 576 } else { 577 objlist_push_tail(&list_main, obj); 578 } 579 obj->refcount++; 580 } 581 582 dbg("checking for required versions"); 583 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 584 rtld_die(); 585 586 if (ld_tracing) { /* We're done */ 587 trace_loaded_objects(obj_main); 588 exit(0); 589 } 590 591 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 592 dump_relocations(obj_main); 593 exit (0); 594 } 595 596 /* 597 * Processing tls relocations requires having the tls offsets 598 * initialized. Prepare offsets before starting initial 599 * relocation processing. 600 */ 601 dbg("initializing initial thread local storage offsets"); 602 STAILQ_FOREACH(entry, &list_main, link) { 603 /* 604 * Allocate all the initial objects out of the static TLS 605 * block even if they didn't ask for it. 606 */ 607 allocate_tls_offset(entry->obj); 608 } 609 610 if (relocate_objects(obj_main, 611 ld_bind_now != NULL && *ld_bind_now != '\0', 612 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 613 rtld_die(); 614 615 dbg("doing copy relocations"); 616 if (do_copy_relocations(obj_main) == -1) 617 rtld_die(); 618 619 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 620 dump_relocations(obj_main); 621 exit (0); 622 } 623 624 /* 625 * Setup TLS for main thread. This must be done after the 626 * relocations are processed, since tls initialization section 627 * might be the subject for relocations. 628 */ 629 dbg("initializing initial thread local storage"); 630 allocate_initial_tls(obj_list); 631 632 dbg("initializing key program variables"); 633 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 634 set_program_var("environ", env); 635 set_program_var("__elf_aux_vector", aux); 636 637 /* Make a list of init functions to call. */ 638 objlist_init(&initlist); 639 initlist_add_objects(obj_list, preload_tail, &initlist); 640 641 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 642 643 map_stacks_exec(NULL); 644 645 dbg("resolving ifuncs"); 646 if (resolve_objects_ifunc(obj_main, 647 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 648 NULL) == -1) 649 rtld_die(); 650 651 if (!obj_main->crt_no_init) { 652 /* 653 * Make sure we don't call the main program's init and fini 654 * functions for binaries linked with old crt1 which calls 655 * _init itself. 656 */ 657 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 658 obj_main->preinit_array = obj_main->init_array = 659 obj_main->fini_array = (Elf_Addr)NULL; 660 } 661 662 wlock_acquire(rtld_bind_lock, &lockstate); 663 if (obj_main->crt_no_init) 664 preinit_main(); 665 objlist_call_init(&initlist, &lockstate); 666 _r_debug_postinit(&obj_main->linkmap); 667 objlist_clear(&initlist); 668 dbg("loading filtees"); 669 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 670 if (ld_loadfltr || obj->z_loadfltr) 671 load_filtees(obj, 0, &lockstate); 672 } 673 lock_release(rtld_bind_lock, &lockstate); 674 675 dbg("transferring control to program entry point = %p", obj_main->entry); 676 677 /* Return the exit procedure and the program entry point. */ 678 *exit_proc = rtld_exit; 679 *objp = obj_main; 680 return (func_ptr_type) obj_main->entry; 681 } 682 683 void * 684 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 685 { 686 void *ptr; 687 Elf_Addr target; 688 689 ptr = (void *)make_function_pointer(def, obj); 690 target = ((Elf_Addr (*)(void))ptr)(); 691 return ((void *)target); 692 } 693 694 Elf_Addr 695 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 696 { 697 const Elf_Rel *rel; 698 const Elf_Sym *def; 699 const Obj_Entry *defobj; 700 Elf_Addr *where; 701 Elf_Addr target; 702 RtldLockState lockstate; 703 704 rlock_acquire(rtld_bind_lock, &lockstate); 705 if (sigsetjmp(lockstate.env, 0) != 0) 706 lock_upgrade(rtld_bind_lock, &lockstate); 707 if (obj->pltrel) 708 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 709 else 710 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 711 712 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 713 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 714 &lockstate); 715 if (def == NULL) 716 rtld_die(); 717 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 718 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 719 else 720 target = (Elf_Addr)(defobj->relocbase + def->st_value); 721 722 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 723 defobj->strtab + def->st_name, basename(obj->path), 724 (void *)target, basename(defobj->path)); 725 726 /* 727 * Write the new contents for the jmpslot. Note that depending on 728 * architecture, the value which we need to return back to the 729 * lazy binding trampoline may or may not be the target 730 * address. The value returned from reloc_jmpslot() is the value 731 * that the trampoline needs. 732 */ 733 target = reloc_jmpslot(where, target, defobj, obj, rel); 734 lock_release(rtld_bind_lock, &lockstate); 735 return target; 736 } 737 738 /* 739 * Error reporting function. Use it like printf. If formats the message 740 * into a buffer, and sets things up so that the next call to dlerror() 741 * will return the message. 742 */ 743 void 744 _rtld_error(const char *fmt, ...) 745 { 746 static char buf[512]; 747 va_list ap; 748 749 va_start(ap, fmt); 750 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 751 error_message = buf; 752 va_end(ap); 753 } 754 755 /* 756 * Return a dynamically-allocated copy of the current error message, if any. 757 */ 758 static char * 759 errmsg_save(void) 760 { 761 return error_message == NULL ? NULL : xstrdup(error_message); 762 } 763 764 /* 765 * Restore the current error message from a copy which was previously saved 766 * by errmsg_save(). The copy is freed. 767 */ 768 static void 769 errmsg_restore(char *saved_msg) 770 { 771 if (saved_msg == NULL) 772 error_message = NULL; 773 else { 774 _rtld_error("%s", saved_msg); 775 free(saved_msg); 776 } 777 } 778 779 static const char * 780 basename(const char *name) 781 { 782 const char *p = strrchr(name, '/'); 783 return p != NULL ? p + 1 : name; 784 } 785 786 static struct utsname uts; 787 788 static char * 789 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 790 const char *subst, bool may_free) 791 { 792 char *p, *p1, *res, *resp; 793 int subst_len, kw_len, subst_count, old_len, new_len; 794 795 kw_len = strlen(kw); 796 797 /* 798 * First, count the number of the keyword occurences, to 799 * preallocate the final string. 800 */ 801 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 802 p1 = strstr(p, kw); 803 if (p1 == NULL) 804 break; 805 } 806 807 /* 808 * If the keyword is not found, just return. 809 * 810 * Return non-substituted string if resolution failed. We 811 * cannot do anything more reasonable, the failure mode of the 812 * caller is unresolved library anyway. 813 */ 814 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 815 return (may_free ? real : xstrdup(real)); 816 if (obj != NULL) 817 subst = obj->origin_path; 818 819 /* 820 * There is indeed something to substitute. Calculate the 821 * length of the resulting string, and allocate it. 822 */ 823 subst_len = strlen(subst); 824 old_len = strlen(real); 825 new_len = old_len + (subst_len - kw_len) * subst_count; 826 res = xmalloc(new_len + 1); 827 828 /* 829 * Now, execute the substitution loop. 830 */ 831 for (p = real, resp = res, *resp = '\0';;) { 832 p1 = strstr(p, kw); 833 if (p1 != NULL) { 834 /* Copy the prefix before keyword. */ 835 memcpy(resp, p, p1 - p); 836 resp += p1 - p; 837 /* Keyword replacement. */ 838 memcpy(resp, subst, subst_len); 839 resp += subst_len; 840 *resp = '\0'; 841 p = p1 + kw_len; 842 } else 843 break; 844 } 845 846 /* Copy to the end of string and finish. */ 847 strcat(resp, p); 848 if (may_free) 849 free(real); 850 return (res); 851 } 852 853 static char * 854 origin_subst(Obj_Entry *obj, char *real) 855 { 856 char *res1, *res2, *res3, *res4; 857 858 if (obj == NULL || !trust) 859 return (xstrdup(real)); 860 if (uts.sysname[0] == '\0') { 861 if (uname(&uts) != 0) { 862 _rtld_error("utsname failed: %d", errno); 863 return (NULL); 864 } 865 } 866 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 867 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 868 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 869 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 870 return (res4); 871 } 872 873 void 874 rtld_die(void) 875 { 876 const char *msg = dlerror(); 877 878 if (msg == NULL) 879 msg = "Fatal error"; 880 rtld_fdputstr(STDERR_FILENO, msg); 881 rtld_fdputchar(STDERR_FILENO, '\n'); 882 _exit(1); 883 } 884 885 /* 886 * Process a shared object's DYNAMIC section, and save the important 887 * information in its Obj_Entry structure. 888 */ 889 static void 890 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 891 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 892 { 893 const Elf_Dyn *dynp; 894 Needed_Entry **needed_tail = &obj->needed; 895 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 896 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 897 const Elf_Hashelt *hashtab; 898 const Elf32_Word *hashval; 899 Elf32_Word bkt, nmaskwords; 900 int bloom_size32; 901 int plttype = DT_REL; 902 903 *dyn_rpath = NULL; 904 *dyn_soname = NULL; 905 *dyn_runpath = NULL; 906 907 obj->bind_now = false; 908 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 909 switch (dynp->d_tag) { 910 911 case DT_REL: 912 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 913 break; 914 915 case DT_RELSZ: 916 obj->relsize = dynp->d_un.d_val; 917 break; 918 919 case DT_RELENT: 920 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 921 break; 922 923 case DT_JMPREL: 924 obj->pltrel = (const Elf_Rel *) 925 (obj->relocbase + dynp->d_un.d_ptr); 926 break; 927 928 case DT_PLTRELSZ: 929 obj->pltrelsize = dynp->d_un.d_val; 930 break; 931 932 case DT_RELA: 933 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 934 break; 935 936 case DT_RELASZ: 937 obj->relasize = dynp->d_un.d_val; 938 break; 939 940 case DT_RELAENT: 941 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 942 break; 943 944 case DT_PLTREL: 945 plttype = dynp->d_un.d_val; 946 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 947 break; 948 949 case DT_SYMTAB: 950 obj->symtab = (const Elf_Sym *) 951 (obj->relocbase + dynp->d_un.d_ptr); 952 break; 953 954 case DT_SYMENT: 955 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 956 break; 957 958 case DT_STRTAB: 959 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 960 break; 961 962 case DT_STRSZ: 963 obj->strsize = dynp->d_un.d_val; 964 break; 965 966 case DT_VERNEED: 967 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 968 dynp->d_un.d_val); 969 break; 970 971 case DT_VERNEEDNUM: 972 obj->verneednum = dynp->d_un.d_val; 973 break; 974 975 case DT_VERDEF: 976 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 977 dynp->d_un.d_val); 978 break; 979 980 case DT_VERDEFNUM: 981 obj->verdefnum = dynp->d_un.d_val; 982 break; 983 984 case DT_VERSYM: 985 obj->versyms = (const Elf_Versym *)(obj->relocbase + 986 dynp->d_un.d_val); 987 break; 988 989 case DT_HASH: 990 { 991 hashtab = (const Elf_Hashelt *)(obj->relocbase + 992 dynp->d_un.d_ptr); 993 obj->nbuckets = hashtab[0]; 994 obj->nchains = hashtab[1]; 995 obj->buckets = hashtab + 2; 996 obj->chains = obj->buckets + obj->nbuckets; 997 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 998 obj->buckets != NULL; 999 } 1000 break; 1001 1002 case DT_GNU_HASH: 1003 { 1004 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1005 dynp->d_un.d_ptr); 1006 obj->nbuckets_gnu = hashtab[0]; 1007 obj->symndx_gnu = hashtab[1]; 1008 nmaskwords = hashtab[2]; 1009 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1010 obj->maskwords_bm_gnu = nmaskwords - 1; 1011 obj->shift2_gnu = hashtab[3]; 1012 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1013 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1014 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1015 obj->symndx_gnu; 1016 /* Number of bitmask words is required to be power of 2 */ 1017 obj->valid_hash_gnu = powerof2(nmaskwords) && 1018 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1019 } 1020 break; 1021 1022 case DT_NEEDED: 1023 if (!obj->rtld) { 1024 Needed_Entry *nep = NEW(Needed_Entry); 1025 nep->name = dynp->d_un.d_val; 1026 nep->obj = NULL; 1027 nep->next = NULL; 1028 1029 *needed_tail = nep; 1030 needed_tail = &nep->next; 1031 } 1032 break; 1033 1034 case DT_FILTER: 1035 if (!obj->rtld) { 1036 Needed_Entry *nep = NEW(Needed_Entry); 1037 nep->name = dynp->d_un.d_val; 1038 nep->obj = NULL; 1039 nep->next = NULL; 1040 1041 *needed_filtees_tail = nep; 1042 needed_filtees_tail = &nep->next; 1043 } 1044 break; 1045 1046 case DT_AUXILIARY: 1047 if (!obj->rtld) { 1048 Needed_Entry *nep = NEW(Needed_Entry); 1049 nep->name = dynp->d_un.d_val; 1050 nep->obj = NULL; 1051 nep->next = NULL; 1052 1053 *needed_aux_filtees_tail = nep; 1054 needed_aux_filtees_tail = &nep->next; 1055 } 1056 break; 1057 1058 case DT_PLTGOT: 1059 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1060 break; 1061 1062 case DT_TEXTREL: 1063 obj->textrel = true; 1064 break; 1065 1066 case DT_SYMBOLIC: 1067 obj->symbolic = true; 1068 break; 1069 1070 case DT_RPATH: 1071 /* 1072 * We have to wait until later to process this, because we 1073 * might not have gotten the address of the string table yet. 1074 */ 1075 *dyn_rpath = dynp; 1076 break; 1077 1078 case DT_SONAME: 1079 *dyn_soname = dynp; 1080 break; 1081 1082 case DT_RUNPATH: 1083 *dyn_runpath = dynp; 1084 break; 1085 1086 case DT_INIT: 1087 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1088 break; 1089 1090 case DT_PREINIT_ARRAY: 1091 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1092 break; 1093 1094 case DT_PREINIT_ARRAYSZ: 1095 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1096 break; 1097 1098 case DT_INIT_ARRAY: 1099 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1100 break; 1101 1102 case DT_INIT_ARRAYSZ: 1103 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1104 break; 1105 1106 case DT_FINI: 1107 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1108 break; 1109 1110 case DT_FINI_ARRAY: 1111 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1112 break; 1113 1114 case DT_FINI_ARRAYSZ: 1115 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1116 break; 1117 1118 /* 1119 * Don't process DT_DEBUG on MIPS as the dynamic section 1120 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1121 */ 1122 1123 #ifndef __mips__ 1124 case DT_DEBUG: 1125 /* XXX - not implemented yet */ 1126 if (!early) 1127 dbg("Filling in DT_DEBUG entry"); 1128 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1129 break; 1130 #endif 1131 1132 case DT_FLAGS: 1133 if (dynp->d_un.d_val & DF_ORIGIN) 1134 obj->z_origin = true; 1135 if (dynp->d_un.d_val & DF_SYMBOLIC) 1136 obj->symbolic = true; 1137 if (dynp->d_un.d_val & DF_TEXTREL) 1138 obj->textrel = true; 1139 if (dynp->d_un.d_val & DF_BIND_NOW) 1140 obj->bind_now = true; 1141 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1142 ;*/ 1143 break; 1144 #ifdef __mips__ 1145 case DT_MIPS_LOCAL_GOTNO: 1146 obj->local_gotno = dynp->d_un.d_val; 1147 break; 1148 1149 case DT_MIPS_SYMTABNO: 1150 obj->symtabno = dynp->d_un.d_val; 1151 break; 1152 1153 case DT_MIPS_GOTSYM: 1154 obj->gotsym = dynp->d_un.d_val; 1155 break; 1156 1157 case DT_MIPS_RLD_MAP: 1158 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1159 break; 1160 #endif 1161 1162 case DT_FLAGS_1: 1163 if (dynp->d_un.d_val & DF_1_NOOPEN) 1164 obj->z_noopen = true; 1165 if (dynp->d_un.d_val & DF_1_ORIGIN) 1166 obj->z_origin = true; 1167 if (dynp->d_un.d_val & DF_1_GLOBAL) 1168 obj->z_global = true; 1169 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1170 obj->bind_now = true; 1171 if (dynp->d_un.d_val & DF_1_NODELETE) 1172 obj->z_nodelete = true; 1173 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1174 obj->z_loadfltr = true; 1175 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1176 obj->z_interpose = true; 1177 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1178 obj->z_nodeflib = true; 1179 break; 1180 1181 default: 1182 if (!early) { 1183 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1184 (long)dynp->d_tag); 1185 } 1186 break; 1187 } 1188 } 1189 1190 obj->traced = false; 1191 1192 if (plttype == DT_RELA) { 1193 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1194 obj->pltrel = NULL; 1195 obj->pltrelasize = obj->pltrelsize; 1196 obj->pltrelsize = 0; 1197 } 1198 1199 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1200 if (obj->valid_hash_sysv) 1201 obj->dynsymcount = obj->nchains; 1202 else if (obj->valid_hash_gnu) { 1203 obj->dynsymcount = 0; 1204 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1205 if (obj->buckets_gnu[bkt] == 0) 1206 continue; 1207 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1208 do 1209 obj->dynsymcount++; 1210 while ((*hashval++ & 1u) == 0); 1211 } 1212 obj->dynsymcount += obj->symndx_gnu; 1213 } 1214 } 1215 1216 static bool 1217 obj_resolve_origin(Obj_Entry *obj) 1218 { 1219 1220 if (obj->origin_path != NULL) 1221 return (true); 1222 obj->origin_path = xmalloc(PATH_MAX); 1223 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1224 } 1225 1226 static void 1227 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1228 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1229 { 1230 1231 if (obj->z_origin && !obj_resolve_origin(obj)) 1232 rtld_die(); 1233 1234 if (dyn_runpath != NULL) { 1235 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1236 obj->runpath = origin_subst(obj, obj->runpath); 1237 } else if (dyn_rpath != NULL) { 1238 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1239 obj->rpath = origin_subst(obj, obj->rpath); 1240 } 1241 if (dyn_soname != NULL) 1242 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1243 } 1244 1245 static void 1246 digest_dynamic(Obj_Entry *obj, int early) 1247 { 1248 const Elf_Dyn *dyn_rpath; 1249 const Elf_Dyn *dyn_soname; 1250 const Elf_Dyn *dyn_runpath; 1251 1252 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1253 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1254 } 1255 1256 /* 1257 * Process a shared object's program header. This is used only for the 1258 * main program, when the kernel has already loaded the main program 1259 * into memory before calling the dynamic linker. It creates and 1260 * returns an Obj_Entry structure. 1261 */ 1262 static Obj_Entry * 1263 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1264 { 1265 Obj_Entry *obj; 1266 const Elf_Phdr *phlimit = phdr + phnum; 1267 const Elf_Phdr *ph; 1268 Elf_Addr note_start, note_end; 1269 int nsegs = 0; 1270 1271 obj = obj_new(); 1272 for (ph = phdr; ph < phlimit; ph++) { 1273 if (ph->p_type != PT_PHDR) 1274 continue; 1275 1276 obj->phdr = phdr; 1277 obj->phsize = ph->p_memsz; 1278 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1279 break; 1280 } 1281 1282 obj->stack_flags = PF_X | PF_R | PF_W; 1283 1284 for (ph = phdr; ph < phlimit; ph++) { 1285 switch (ph->p_type) { 1286 1287 case PT_INTERP: 1288 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1289 break; 1290 1291 case PT_LOAD: 1292 if (nsegs == 0) { /* First load segment */ 1293 obj->vaddrbase = trunc_page(ph->p_vaddr); 1294 obj->mapbase = obj->vaddrbase + obj->relocbase; 1295 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1296 obj->vaddrbase; 1297 } else { /* Last load segment */ 1298 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1299 obj->vaddrbase; 1300 } 1301 nsegs++; 1302 break; 1303 1304 case PT_DYNAMIC: 1305 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1306 break; 1307 1308 case PT_TLS: 1309 obj->tlsindex = 1; 1310 obj->tlssize = ph->p_memsz; 1311 obj->tlsalign = ph->p_align; 1312 obj->tlsinitsize = ph->p_filesz; 1313 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1314 break; 1315 1316 case PT_GNU_STACK: 1317 obj->stack_flags = ph->p_flags; 1318 break; 1319 1320 case PT_GNU_RELRO: 1321 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1322 obj->relro_size = round_page(ph->p_memsz); 1323 break; 1324 1325 case PT_NOTE: 1326 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1327 note_end = note_start + ph->p_filesz; 1328 digest_notes(obj, note_start, note_end); 1329 break; 1330 } 1331 } 1332 if (nsegs < 1) { 1333 _rtld_error("%s: too few PT_LOAD segments", path); 1334 return NULL; 1335 } 1336 1337 obj->entry = entry; 1338 return obj; 1339 } 1340 1341 void 1342 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1343 { 1344 const Elf_Note *note; 1345 const char *note_name; 1346 uintptr_t p; 1347 1348 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1349 note = (const Elf_Note *)((const char *)(note + 1) + 1350 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1351 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1352 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1353 note->n_descsz != sizeof(int32_t)) 1354 continue; 1355 if (note->n_type != ABI_NOTETYPE && 1356 note->n_type != CRT_NOINIT_NOTETYPE) 1357 continue; 1358 note_name = (const char *)(note + 1); 1359 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1360 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1361 continue; 1362 switch (note->n_type) { 1363 case ABI_NOTETYPE: 1364 /* FreeBSD osrel note */ 1365 p = (uintptr_t)(note + 1); 1366 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1367 obj->osrel = *(const int32_t *)(p); 1368 dbg("note osrel %d", obj->osrel); 1369 break; 1370 case CRT_NOINIT_NOTETYPE: 1371 /* FreeBSD 'crt does not call init' note */ 1372 obj->crt_no_init = true; 1373 dbg("note crt_no_init"); 1374 break; 1375 } 1376 } 1377 } 1378 1379 static Obj_Entry * 1380 dlcheck(void *handle) 1381 { 1382 Obj_Entry *obj; 1383 1384 for (obj = obj_list; obj != NULL; obj = obj->next) 1385 if (obj == (Obj_Entry *) handle) 1386 break; 1387 1388 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1389 _rtld_error("Invalid shared object handle %p", handle); 1390 return NULL; 1391 } 1392 return obj; 1393 } 1394 1395 /* 1396 * If the given object is already in the donelist, return true. Otherwise 1397 * add the object to the list and return false. 1398 */ 1399 static bool 1400 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1401 { 1402 unsigned int i; 1403 1404 for (i = 0; i < dlp->num_used; i++) 1405 if (dlp->objs[i] == obj) 1406 return true; 1407 /* 1408 * Our donelist allocation should always be sufficient. But if 1409 * our threads locking isn't working properly, more shared objects 1410 * could have been loaded since we allocated the list. That should 1411 * never happen, but we'll handle it properly just in case it does. 1412 */ 1413 if (dlp->num_used < dlp->num_alloc) 1414 dlp->objs[dlp->num_used++] = obj; 1415 return false; 1416 } 1417 1418 /* 1419 * Hash function for symbol table lookup. Don't even think about changing 1420 * this. It is specified by the System V ABI. 1421 */ 1422 unsigned long 1423 elf_hash(const char *name) 1424 { 1425 const unsigned char *p = (const unsigned char *) name; 1426 unsigned long h = 0; 1427 unsigned long g; 1428 1429 while (*p != '\0') { 1430 h = (h << 4) + *p++; 1431 if ((g = h & 0xf0000000) != 0) 1432 h ^= g >> 24; 1433 h &= ~g; 1434 } 1435 return h; 1436 } 1437 1438 /* 1439 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1440 * unsigned in case it's implemented with a wider type. 1441 */ 1442 static uint32_t 1443 gnu_hash(const char *s) 1444 { 1445 uint32_t h; 1446 unsigned char c; 1447 1448 h = 5381; 1449 for (c = *s; c != '\0'; c = *++s) 1450 h = h * 33 + c; 1451 return (h & 0xffffffff); 1452 } 1453 1454 1455 /* 1456 * Find the library with the given name, and return its full pathname. 1457 * The returned string is dynamically allocated. Generates an error 1458 * message and returns NULL if the library cannot be found. 1459 * 1460 * If the second argument is non-NULL, then it refers to an already- 1461 * loaded shared object, whose library search path will be searched. 1462 * 1463 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1464 * descriptor (which is close-on-exec) will be passed out via the third 1465 * argument. 1466 * 1467 * The search order is: 1468 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1469 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1470 * LD_LIBRARY_PATH 1471 * DT_RUNPATH in the referencing file 1472 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1473 * from list) 1474 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1475 * 1476 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1477 */ 1478 static char * 1479 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1480 { 1481 char *pathname; 1482 char *name; 1483 bool nodeflib, objgiven; 1484 1485 objgiven = refobj != NULL; 1486 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1487 if (xname[0] != '/' && !trust) { 1488 _rtld_error("Absolute pathname required for shared object \"%s\"", 1489 xname); 1490 return NULL; 1491 } 1492 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1493 __DECONST(char *, xname))); 1494 } 1495 1496 if (libmap_disable || !objgiven || 1497 (name = lm_find(refobj->path, xname)) == NULL) 1498 name = (char *)xname; 1499 1500 dbg(" Searching for \"%s\"", name); 1501 1502 /* 1503 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1504 * back to pre-conforming behaviour if user requested so with 1505 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1506 * nodeflib. 1507 */ 1508 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1509 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1510 (refobj != NULL && 1511 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1512 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1513 (pathname = search_library_path(name, gethints(false))) != NULL || 1514 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1515 return (pathname); 1516 } else { 1517 nodeflib = objgiven ? refobj->z_nodeflib : false; 1518 if ((objgiven && 1519 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1520 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1521 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1522 (pathname = search_library_path(name, ld_library_path)) != NULL || 1523 (objgiven && 1524 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1525 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1526 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1527 (objgiven && !nodeflib && 1528 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1529 return (pathname); 1530 } 1531 1532 if (objgiven && refobj->path != NULL) { 1533 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1534 name, basename(refobj->path)); 1535 } else { 1536 _rtld_error("Shared object \"%s\" not found", name); 1537 } 1538 return NULL; 1539 } 1540 1541 /* 1542 * Given a symbol number in a referencing object, find the corresponding 1543 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1544 * no definition was found. Returns a pointer to the Obj_Entry of the 1545 * defining object via the reference parameter DEFOBJ_OUT. 1546 */ 1547 const Elf_Sym * 1548 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1549 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1550 RtldLockState *lockstate) 1551 { 1552 const Elf_Sym *ref; 1553 const Elf_Sym *def; 1554 const Obj_Entry *defobj; 1555 SymLook req; 1556 const char *name; 1557 int res; 1558 1559 /* 1560 * If we have already found this symbol, get the information from 1561 * the cache. 1562 */ 1563 if (symnum >= refobj->dynsymcount) 1564 return NULL; /* Bad object */ 1565 if (cache != NULL && cache[symnum].sym != NULL) { 1566 *defobj_out = cache[symnum].obj; 1567 return cache[symnum].sym; 1568 } 1569 1570 ref = refobj->symtab + symnum; 1571 name = refobj->strtab + ref->st_name; 1572 def = NULL; 1573 defobj = NULL; 1574 1575 /* 1576 * We don't have to do a full scale lookup if the symbol is local. 1577 * We know it will bind to the instance in this load module; to 1578 * which we already have a pointer (ie ref). By not doing a lookup, 1579 * we not only improve performance, but it also avoids unresolvable 1580 * symbols when local symbols are not in the hash table. This has 1581 * been seen with the ia64 toolchain. 1582 */ 1583 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1584 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1585 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1586 symnum); 1587 } 1588 symlook_init(&req, name); 1589 req.flags = flags; 1590 req.ventry = fetch_ventry(refobj, symnum); 1591 req.lockstate = lockstate; 1592 res = symlook_default(&req, refobj); 1593 if (res == 0) { 1594 def = req.sym_out; 1595 defobj = req.defobj_out; 1596 } 1597 } else { 1598 def = ref; 1599 defobj = refobj; 1600 } 1601 1602 /* 1603 * If we found no definition and the reference is weak, treat the 1604 * symbol as having the value zero. 1605 */ 1606 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1607 def = &sym_zero; 1608 defobj = obj_main; 1609 } 1610 1611 if (def != NULL) { 1612 *defobj_out = defobj; 1613 /* Record the information in the cache to avoid subsequent lookups. */ 1614 if (cache != NULL) { 1615 cache[symnum].sym = def; 1616 cache[symnum].obj = defobj; 1617 } 1618 } else { 1619 if (refobj != &obj_rtld) 1620 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1621 } 1622 return def; 1623 } 1624 1625 /* 1626 * Return the search path from the ldconfig hints file, reading it if 1627 * necessary. If nostdlib is true, then the default search paths are 1628 * not added to result. 1629 * 1630 * Returns NULL if there are problems with the hints file, 1631 * or if the search path there is empty. 1632 */ 1633 static const char * 1634 gethints(bool nostdlib) 1635 { 1636 static char *hints, *filtered_path; 1637 struct elfhints_hdr hdr; 1638 struct fill_search_info_args sargs, hargs; 1639 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1640 struct dl_serpath *SLPpath, *hintpath; 1641 char *p; 1642 unsigned int SLPndx, hintndx, fndx, fcount; 1643 int fd; 1644 size_t flen; 1645 bool skip; 1646 1647 /* First call, read the hints file */ 1648 if (hints == NULL) { 1649 /* Keep from trying again in case the hints file is bad. */ 1650 hints = ""; 1651 1652 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1653 return (NULL); 1654 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1655 hdr.magic != ELFHINTS_MAGIC || 1656 hdr.version != 1) { 1657 close(fd); 1658 return (NULL); 1659 } 1660 p = xmalloc(hdr.dirlistlen + 1); 1661 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1662 read(fd, p, hdr.dirlistlen + 1) != 1663 (ssize_t)hdr.dirlistlen + 1) { 1664 free(p); 1665 close(fd); 1666 return (NULL); 1667 } 1668 hints = p; 1669 close(fd); 1670 } 1671 1672 /* 1673 * If caller agreed to receive list which includes the default 1674 * paths, we are done. Otherwise, if we still did not 1675 * calculated filtered result, do it now. 1676 */ 1677 if (!nostdlib) 1678 return (hints[0] != '\0' ? hints : NULL); 1679 if (filtered_path != NULL) 1680 goto filt_ret; 1681 1682 /* 1683 * Obtain the list of all configured search paths, and the 1684 * list of the default paths. 1685 * 1686 * First estimate the size of the results. 1687 */ 1688 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1689 smeta.dls_cnt = 0; 1690 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1691 hmeta.dls_cnt = 0; 1692 1693 sargs.request = RTLD_DI_SERINFOSIZE; 1694 sargs.serinfo = &smeta; 1695 hargs.request = RTLD_DI_SERINFOSIZE; 1696 hargs.serinfo = &hmeta; 1697 1698 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1699 path_enumerate(p, fill_search_info, &hargs); 1700 1701 SLPinfo = xmalloc(smeta.dls_size); 1702 hintinfo = xmalloc(hmeta.dls_size); 1703 1704 /* 1705 * Next fetch both sets of paths. 1706 */ 1707 sargs.request = RTLD_DI_SERINFO; 1708 sargs.serinfo = SLPinfo; 1709 sargs.serpath = &SLPinfo->dls_serpath[0]; 1710 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1711 1712 hargs.request = RTLD_DI_SERINFO; 1713 hargs.serinfo = hintinfo; 1714 hargs.serpath = &hintinfo->dls_serpath[0]; 1715 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1716 1717 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1718 path_enumerate(p, fill_search_info, &hargs); 1719 1720 /* 1721 * Now calculate the difference between two sets, by excluding 1722 * standard paths from the full set. 1723 */ 1724 fndx = 0; 1725 fcount = 0; 1726 filtered_path = xmalloc(hdr.dirlistlen + 1); 1727 hintpath = &hintinfo->dls_serpath[0]; 1728 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1729 skip = false; 1730 SLPpath = &SLPinfo->dls_serpath[0]; 1731 /* 1732 * Check each standard path against current. 1733 */ 1734 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1735 /* matched, skip the path */ 1736 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1737 skip = true; 1738 break; 1739 } 1740 } 1741 if (skip) 1742 continue; 1743 /* 1744 * Not matched against any standard path, add the path 1745 * to result. Separate consequtive paths with ':'. 1746 */ 1747 if (fcount > 0) { 1748 filtered_path[fndx] = ':'; 1749 fndx++; 1750 } 1751 fcount++; 1752 flen = strlen(hintpath->dls_name); 1753 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1754 fndx += flen; 1755 } 1756 filtered_path[fndx] = '\0'; 1757 1758 free(SLPinfo); 1759 free(hintinfo); 1760 1761 filt_ret: 1762 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1763 } 1764 1765 static void 1766 init_dag(Obj_Entry *root) 1767 { 1768 const Needed_Entry *needed; 1769 const Objlist_Entry *elm; 1770 DoneList donelist; 1771 1772 if (root->dag_inited) 1773 return; 1774 donelist_init(&donelist); 1775 1776 /* Root object belongs to own DAG. */ 1777 objlist_push_tail(&root->dldags, root); 1778 objlist_push_tail(&root->dagmembers, root); 1779 donelist_check(&donelist, root); 1780 1781 /* 1782 * Add dependencies of root object to DAG in breadth order 1783 * by exploiting the fact that each new object get added 1784 * to the tail of the dagmembers list. 1785 */ 1786 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1787 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1788 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1789 continue; 1790 objlist_push_tail(&needed->obj->dldags, root); 1791 objlist_push_tail(&root->dagmembers, needed->obj); 1792 } 1793 } 1794 root->dag_inited = true; 1795 } 1796 1797 static void 1798 process_z(Obj_Entry *root) 1799 { 1800 const Objlist_Entry *elm; 1801 Obj_Entry *obj; 1802 1803 /* 1804 * Walk over object DAG and process every dependent object 1805 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1806 * to grow their own DAG. 1807 * 1808 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1809 * symlook_global() to work. 1810 * 1811 * For DF_1_NODELETE, the DAG should have its reference upped. 1812 */ 1813 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1814 obj = elm->obj; 1815 if (obj == NULL) 1816 continue; 1817 if (obj->z_nodelete && !obj->ref_nodel) { 1818 dbg("obj %s -z nodelete", obj->path); 1819 init_dag(obj); 1820 ref_dag(obj); 1821 obj->ref_nodel = true; 1822 } 1823 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1824 dbg("obj %s -z global", obj->path); 1825 objlist_push_tail(&list_global, obj); 1826 init_dag(obj); 1827 } 1828 } 1829 } 1830 /* 1831 * Initialize the dynamic linker. The argument is the address at which 1832 * the dynamic linker has been mapped into memory. The primary task of 1833 * this function is to relocate the dynamic linker. 1834 */ 1835 static void 1836 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1837 { 1838 Obj_Entry objtmp; /* Temporary rtld object */ 1839 const Elf_Dyn *dyn_rpath; 1840 const Elf_Dyn *dyn_soname; 1841 const Elf_Dyn *dyn_runpath; 1842 1843 #ifdef RTLD_INIT_PAGESIZES_EARLY 1844 /* The page size is required by the dynamic memory allocator. */ 1845 init_pagesizes(aux_info); 1846 #endif 1847 1848 /* 1849 * Conjure up an Obj_Entry structure for the dynamic linker. 1850 * 1851 * The "path" member can't be initialized yet because string constants 1852 * cannot yet be accessed. Below we will set it correctly. 1853 */ 1854 memset(&objtmp, 0, sizeof(objtmp)); 1855 objtmp.path = NULL; 1856 objtmp.rtld = true; 1857 objtmp.mapbase = mapbase; 1858 #ifdef PIC 1859 objtmp.relocbase = mapbase; 1860 #endif 1861 if (RTLD_IS_DYNAMIC()) { 1862 objtmp.dynamic = rtld_dynamic(&objtmp); 1863 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1864 assert(objtmp.needed == NULL); 1865 #if !defined(__mips__) 1866 /* MIPS has a bogus DT_TEXTREL. */ 1867 assert(!objtmp.textrel); 1868 #endif 1869 1870 /* 1871 * Temporarily put the dynamic linker entry into the object list, so 1872 * that symbols can be found. 1873 */ 1874 1875 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1876 } 1877 1878 /* Initialize the object list. */ 1879 obj_tail = &obj_list; 1880 1881 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1882 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1883 1884 #ifndef RTLD_INIT_PAGESIZES_EARLY 1885 /* The page size is required by the dynamic memory allocator. */ 1886 init_pagesizes(aux_info); 1887 #endif 1888 1889 if (aux_info[AT_OSRELDATE] != NULL) 1890 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1891 1892 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1893 1894 /* Replace the path with a dynamically allocated copy. */ 1895 obj_rtld.path = xstrdup(PATH_RTLD); 1896 1897 r_debug.r_brk = r_debug_state; 1898 r_debug.r_state = RT_CONSISTENT; 1899 } 1900 1901 /* 1902 * Retrieve the array of supported page sizes. The kernel provides the page 1903 * sizes in increasing order. 1904 */ 1905 static void 1906 init_pagesizes(Elf_Auxinfo **aux_info) 1907 { 1908 static size_t psa[MAXPAGESIZES]; 1909 int mib[2]; 1910 size_t len, size; 1911 1912 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1913 NULL) { 1914 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1915 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1916 } else { 1917 len = 2; 1918 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1919 size = sizeof(psa); 1920 else { 1921 /* As a fallback, retrieve the base page size. */ 1922 size = sizeof(psa[0]); 1923 if (aux_info[AT_PAGESZ] != NULL) { 1924 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1925 goto psa_filled; 1926 } else { 1927 mib[0] = CTL_HW; 1928 mib[1] = HW_PAGESIZE; 1929 len = 2; 1930 } 1931 } 1932 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1933 _rtld_error("sysctl for hw.pagesize(s) failed"); 1934 rtld_die(); 1935 } 1936 psa_filled: 1937 pagesizes = psa; 1938 } 1939 npagesizes = size / sizeof(pagesizes[0]); 1940 /* Discard any invalid entries at the end of the array. */ 1941 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1942 npagesizes--; 1943 } 1944 1945 /* 1946 * Add the init functions from a needed object list (and its recursive 1947 * needed objects) to "list". This is not used directly; it is a helper 1948 * function for initlist_add_objects(). The write lock must be held 1949 * when this function is called. 1950 */ 1951 static void 1952 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1953 { 1954 /* Recursively process the successor needed objects. */ 1955 if (needed->next != NULL) 1956 initlist_add_neededs(needed->next, list); 1957 1958 /* Process the current needed object. */ 1959 if (needed->obj != NULL) 1960 initlist_add_objects(needed->obj, &needed->obj->next, list); 1961 } 1962 1963 /* 1964 * Scan all of the DAGs rooted in the range of objects from "obj" to 1965 * "tail" and add their init functions to "list". This recurses over 1966 * the DAGs and ensure the proper init ordering such that each object's 1967 * needed libraries are initialized before the object itself. At the 1968 * same time, this function adds the objects to the global finalization 1969 * list "list_fini" in the opposite order. The write lock must be 1970 * held when this function is called. 1971 */ 1972 static void 1973 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1974 { 1975 1976 if (obj->init_scanned || obj->init_done) 1977 return; 1978 obj->init_scanned = true; 1979 1980 /* Recursively process the successor objects. */ 1981 if (&obj->next != tail) 1982 initlist_add_objects(obj->next, tail, list); 1983 1984 /* Recursively process the needed objects. */ 1985 if (obj->needed != NULL) 1986 initlist_add_neededs(obj->needed, list); 1987 if (obj->needed_filtees != NULL) 1988 initlist_add_neededs(obj->needed_filtees, list); 1989 if (obj->needed_aux_filtees != NULL) 1990 initlist_add_neededs(obj->needed_aux_filtees, list); 1991 1992 /* Add the object to the init list. */ 1993 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1994 obj->init_array != (Elf_Addr)NULL) 1995 objlist_push_tail(list, obj); 1996 1997 /* Add the object to the global fini list in the reverse order. */ 1998 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 1999 && !obj->on_fini_list) { 2000 objlist_push_head(&list_fini, obj); 2001 obj->on_fini_list = true; 2002 } 2003 } 2004 2005 #ifndef FPTR_TARGET 2006 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2007 #endif 2008 2009 static void 2010 free_needed_filtees(Needed_Entry *n) 2011 { 2012 Needed_Entry *needed, *needed1; 2013 2014 for (needed = n; needed != NULL; needed = needed->next) { 2015 if (needed->obj != NULL) { 2016 dlclose(needed->obj); 2017 needed->obj = NULL; 2018 } 2019 } 2020 for (needed = n; needed != NULL; needed = needed1) { 2021 needed1 = needed->next; 2022 free(needed); 2023 } 2024 } 2025 2026 static void 2027 unload_filtees(Obj_Entry *obj) 2028 { 2029 2030 free_needed_filtees(obj->needed_filtees); 2031 obj->needed_filtees = NULL; 2032 free_needed_filtees(obj->needed_aux_filtees); 2033 obj->needed_aux_filtees = NULL; 2034 obj->filtees_loaded = false; 2035 } 2036 2037 static void 2038 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2039 RtldLockState *lockstate) 2040 { 2041 2042 for (; needed != NULL; needed = needed->next) { 2043 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2044 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2045 RTLD_LOCAL, lockstate); 2046 } 2047 } 2048 2049 static void 2050 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2051 { 2052 2053 lock_restart_for_upgrade(lockstate); 2054 if (!obj->filtees_loaded) { 2055 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2056 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2057 obj->filtees_loaded = true; 2058 } 2059 } 2060 2061 static int 2062 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2063 { 2064 Obj_Entry *obj1; 2065 2066 for (; needed != NULL; needed = needed->next) { 2067 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2068 flags & ~RTLD_LO_NOLOAD); 2069 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2070 return (-1); 2071 } 2072 return (0); 2073 } 2074 2075 /* 2076 * Given a shared object, traverse its list of needed objects, and load 2077 * each of them. Returns 0 on success. Generates an error message and 2078 * returns -1 on failure. 2079 */ 2080 static int 2081 load_needed_objects(Obj_Entry *first, int flags) 2082 { 2083 Obj_Entry *obj; 2084 2085 for (obj = first; obj != NULL; obj = obj->next) { 2086 if (process_needed(obj, obj->needed, flags) == -1) 2087 return (-1); 2088 } 2089 return (0); 2090 } 2091 2092 static int 2093 load_preload_objects(void) 2094 { 2095 char *p = ld_preload; 2096 Obj_Entry *obj; 2097 static const char delim[] = " \t:;"; 2098 2099 if (p == NULL) 2100 return 0; 2101 2102 p += strspn(p, delim); 2103 while (*p != '\0') { 2104 size_t len = strcspn(p, delim); 2105 char savech; 2106 2107 savech = p[len]; 2108 p[len] = '\0'; 2109 obj = load_object(p, -1, NULL, 0); 2110 if (obj == NULL) 2111 return -1; /* XXX - cleanup */ 2112 obj->z_interpose = true; 2113 p[len] = savech; 2114 p += len; 2115 p += strspn(p, delim); 2116 } 2117 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2118 return 0; 2119 } 2120 2121 static const char * 2122 printable_path(const char *path) 2123 { 2124 2125 return (path == NULL ? "<unknown>" : path); 2126 } 2127 2128 /* 2129 * Load a shared object into memory, if it is not already loaded. The 2130 * object may be specified by name or by user-supplied file descriptor 2131 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2132 * duplicate is. 2133 * 2134 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2135 * on failure. 2136 */ 2137 static Obj_Entry * 2138 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2139 { 2140 Obj_Entry *obj; 2141 int fd; 2142 struct stat sb; 2143 char *path; 2144 2145 fd = -1; 2146 if (name != NULL) { 2147 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2148 if (object_match_name(obj, name)) 2149 return (obj); 2150 } 2151 2152 path = find_library(name, refobj, &fd); 2153 if (path == NULL) 2154 return (NULL); 2155 } else 2156 path = NULL; 2157 2158 if (fd >= 0) { 2159 /* 2160 * search_library_pathfds() opens a fresh file descriptor for the 2161 * library, so there is no need to dup(). 2162 */ 2163 } else if (fd_u == -1) { 2164 /* 2165 * If we didn't find a match by pathname, or the name is not 2166 * supplied, open the file and check again by device and inode. 2167 * This avoids false mismatches caused by multiple links or ".." 2168 * in pathnames. 2169 * 2170 * To avoid a race, we open the file and use fstat() rather than 2171 * using stat(). 2172 */ 2173 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2174 _rtld_error("Cannot open \"%s\"", path); 2175 free(path); 2176 return (NULL); 2177 } 2178 } else { 2179 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2180 if (fd == -1) { 2181 _rtld_error("Cannot dup fd"); 2182 free(path); 2183 return (NULL); 2184 } 2185 } 2186 if (fstat(fd, &sb) == -1) { 2187 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2188 close(fd); 2189 free(path); 2190 return NULL; 2191 } 2192 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2193 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2194 break; 2195 if (obj != NULL && name != NULL) { 2196 object_add_name(obj, name); 2197 free(path); 2198 close(fd); 2199 return obj; 2200 } 2201 if (flags & RTLD_LO_NOLOAD) { 2202 free(path); 2203 close(fd); 2204 return (NULL); 2205 } 2206 2207 /* First use of this object, so we must map it in */ 2208 obj = do_load_object(fd, name, path, &sb, flags); 2209 if (obj == NULL) 2210 free(path); 2211 close(fd); 2212 2213 return obj; 2214 } 2215 2216 static Obj_Entry * 2217 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2218 int flags) 2219 { 2220 Obj_Entry *obj; 2221 struct statfs fs; 2222 2223 /* 2224 * but first, make sure that environment variables haven't been 2225 * used to circumvent the noexec flag on a filesystem. 2226 */ 2227 if (dangerous_ld_env) { 2228 if (fstatfs(fd, &fs) != 0) { 2229 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2230 return NULL; 2231 } 2232 if (fs.f_flags & MNT_NOEXEC) { 2233 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2234 return NULL; 2235 } 2236 } 2237 dbg("loading \"%s\"", printable_path(path)); 2238 obj = map_object(fd, printable_path(path), sbp); 2239 if (obj == NULL) 2240 return NULL; 2241 2242 /* 2243 * If DT_SONAME is present in the object, digest_dynamic2 already 2244 * added it to the object names. 2245 */ 2246 if (name != NULL) 2247 object_add_name(obj, name); 2248 obj->path = path; 2249 digest_dynamic(obj, 0); 2250 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2251 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2252 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2253 RTLD_LO_DLOPEN) { 2254 dbg("refusing to load non-loadable \"%s\"", obj->path); 2255 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2256 munmap(obj->mapbase, obj->mapsize); 2257 obj_free(obj); 2258 return (NULL); 2259 } 2260 2261 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2262 *obj_tail = obj; 2263 obj_tail = &obj->next; 2264 obj_count++; 2265 obj_loads++; 2266 linkmap_add(obj); /* for GDB & dlinfo() */ 2267 max_stack_flags |= obj->stack_flags; 2268 2269 dbg(" %p .. %p: %s", obj->mapbase, 2270 obj->mapbase + obj->mapsize - 1, obj->path); 2271 if (obj->textrel) 2272 dbg(" WARNING: %s has impure text", obj->path); 2273 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2274 obj->path); 2275 2276 return obj; 2277 } 2278 2279 static Obj_Entry * 2280 obj_from_addr(const void *addr) 2281 { 2282 Obj_Entry *obj; 2283 2284 for (obj = obj_list; obj != NULL; obj = obj->next) { 2285 if (addr < (void *) obj->mapbase) 2286 continue; 2287 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2288 return obj; 2289 } 2290 return NULL; 2291 } 2292 2293 static void 2294 preinit_main(void) 2295 { 2296 Elf_Addr *preinit_addr; 2297 int index; 2298 2299 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2300 if (preinit_addr == NULL) 2301 return; 2302 2303 for (index = 0; index < obj_main->preinit_array_num; index++) { 2304 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2305 dbg("calling preinit function for %s at %p", obj_main->path, 2306 (void *)preinit_addr[index]); 2307 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2308 0, 0, obj_main->path); 2309 call_init_pointer(obj_main, preinit_addr[index]); 2310 } 2311 } 2312 } 2313 2314 /* 2315 * Call the finalization functions for each of the objects in "list" 2316 * belonging to the DAG of "root" and referenced once. If NULL "root" 2317 * is specified, every finalization function will be called regardless 2318 * of the reference count and the list elements won't be freed. All of 2319 * the objects are expected to have non-NULL fini functions. 2320 */ 2321 static void 2322 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2323 { 2324 Objlist_Entry *elm; 2325 char *saved_msg; 2326 Elf_Addr *fini_addr; 2327 int index; 2328 2329 assert(root == NULL || root->refcount == 1); 2330 2331 /* 2332 * Preserve the current error message since a fini function might 2333 * call into the dynamic linker and overwrite it. 2334 */ 2335 saved_msg = errmsg_save(); 2336 do { 2337 STAILQ_FOREACH(elm, list, link) { 2338 if (root != NULL && (elm->obj->refcount != 1 || 2339 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2340 continue; 2341 /* Remove object from fini list to prevent recursive invocation. */ 2342 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2343 /* 2344 * XXX: If a dlopen() call references an object while the 2345 * fini function is in progress, we might end up trying to 2346 * unload the referenced object in dlclose() or the object 2347 * won't be unloaded although its fini function has been 2348 * called. 2349 */ 2350 lock_release(rtld_bind_lock, lockstate); 2351 2352 /* 2353 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2354 * When this happens, DT_FINI_ARRAY is processed first. 2355 */ 2356 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2357 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2358 for (index = elm->obj->fini_array_num - 1; index >= 0; 2359 index--) { 2360 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2361 dbg("calling fini function for %s at %p", 2362 elm->obj->path, (void *)fini_addr[index]); 2363 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2364 (void *)fini_addr[index], 0, 0, elm->obj->path); 2365 call_initfini_pointer(elm->obj, fini_addr[index]); 2366 } 2367 } 2368 } 2369 if (elm->obj->fini != (Elf_Addr)NULL) { 2370 dbg("calling fini function for %s at %p", elm->obj->path, 2371 (void *)elm->obj->fini); 2372 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2373 0, 0, elm->obj->path); 2374 call_initfini_pointer(elm->obj, elm->obj->fini); 2375 } 2376 wlock_acquire(rtld_bind_lock, lockstate); 2377 /* No need to free anything if process is going down. */ 2378 if (root != NULL) 2379 free(elm); 2380 /* 2381 * We must restart the list traversal after every fini call 2382 * because a dlclose() call from the fini function or from 2383 * another thread might have modified the reference counts. 2384 */ 2385 break; 2386 } 2387 } while (elm != NULL); 2388 errmsg_restore(saved_msg); 2389 } 2390 2391 /* 2392 * Call the initialization functions for each of the objects in 2393 * "list". All of the objects are expected to have non-NULL init 2394 * functions. 2395 */ 2396 static void 2397 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2398 { 2399 Objlist_Entry *elm; 2400 Obj_Entry *obj; 2401 char *saved_msg; 2402 Elf_Addr *init_addr; 2403 int index; 2404 2405 /* 2406 * Clean init_scanned flag so that objects can be rechecked and 2407 * possibly initialized earlier if any of vectors called below 2408 * cause the change by using dlopen. 2409 */ 2410 for (obj = obj_list; obj != NULL; obj = obj->next) 2411 obj->init_scanned = false; 2412 2413 /* 2414 * Preserve the current error message since an init function might 2415 * call into the dynamic linker and overwrite it. 2416 */ 2417 saved_msg = errmsg_save(); 2418 STAILQ_FOREACH(elm, list, link) { 2419 if (elm->obj->init_done) /* Initialized early. */ 2420 continue; 2421 /* 2422 * Race: other thread might try to use this object before current 2423 * one completes the initilization. Not much can be done here 2424 * without better locking. 2425 */ 2426 elm->obj->init_done = true; 2427 lock_release(rtld_bind_lock, lockstate); 2428 2429 /* 2430 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2431 * When this happens, DT_INIT is processed first. 2432 */ 2433 if (elm->obj->init != (Elf_Addr)NULL) { 2434 dbg("calling init function for %s at %p", elm->obj->path, 2435 (void *)elm->obj->init); 2436 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2437 0, 0, elm->obj->path); 2438 call_initfini_pointer(elm->obj, elm->obj->init); 2439 } 2440 init_addr = (Elf_Addr *)elm->obj->init_array; 2441 if (init_addr != NULL) { 2442 for (index = 0; index < elm->obj->init_array_num; index++) { 2443 if (init_addr[index] != 0 && init_addr[index] != 1) { 2444 dbg("calling init function for %s at %p", elm->obj->path, 2445 (void *)init_addr[index]); 2446 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2447 (void *)init_addr[index], 0, 0, elm->obj->path); 2448 call_init_pointer(elm->obj, init_addr[index]); 2449 } 2450 } 2451 } 2452 wlock_acquire(rtld_bind_lock, lockstate); 2453 } 2454 errmsg_restore(saved_msg); 2455 } 2456 2457 static void 2458 objlist_clear(Objlist *list) 2459 { 2460 Objlist_Entry *elm; 2461 2462 while (!STAILQ_EMPTY(list)) { 2463 elm = STAILQ_FIRST(list); 2464 STAILQ_REMOVE_HEAD(list, link); 2465 free(elm); 2466 } 2467 } 2468 2469 static Objlist_Entry * 2470 objlist_find(Objlist *list, const Obj_Entry *obj) 2471 { 2472 Objlist_Entry *elm; 2473 2474 STAILQ_FOREACH(elm, list, link) 2475 if (elm->obj == obj) 2476 return elm; 2477 return NULL; 2478 } 2479 2480 static void 2481 objlist_init(Objlist *list) 2482 { 2483 STAILQ_INIT(list); 2484 } 2485 2486 static void 2487 objlist_push_head(Objlist *list, Obj_Entry *obj) 2488 { 2489 Objlist_Entry *elm; 2490 2491 elm = NEW(Objlist_Entry); 2492 elm->obj = obj; 2493 STAILQ_INSERT_HEAD(list, elm, link); 2494 } 2495 2496 static void 2497 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2498 { 2499 Objlist_Entry *elm; 2500 2501 elm = NEW(Objlist_Entry); 2502 elm->obj = obj; 2503 STAILQ_INSERT_TAIL(list, elm, link); 2504 } 2505 2506 static void 2507 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2508 { 2509 Objlist_Entry *elm, *listelm; 2510 2511 STAILQ_FOREACH(listelm, list, link) { 2512 if (listelm->obj == listobj) 2513 break; 2514 } 2515 elm = NEW(Objlist_Entry); 2516 elm->obj = obj; 2517 if (listelm != NULL) 2518 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2519 else 2520 STAILQ_INSERT_TAIL(list, elm, link); 2521 } 2522 2523 static void 2524 objlist_remove(Objlist *list, Obj_Entry *obj) 2525 { 2526 Objlist_Entry *elm; 2527 2528 if ((elm = objlist_find(list, obj)) != NULL) { 2529 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2530 free(elm); 2531 } 2532 } 2533 2534 /* 2535 * Relocate dag rooted in the specified object. 2536 * Returns 0 on success, or -1 on failure. 2537 */ 2538 2539 static int 2540 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2541 int flags, RtldLockState *lockstate) 2542 { 2543 Objlist_Entry *elm; 2544 int error; 2545 2546 error = 0; 2547 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2548 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2549 lockstate); 2550 if (error == -1) 2551 break; 2552 } 2553 return (error); 2554 } 2555 2556 /* 2557 * Relocate single object. 2558 * Returns 0 on success, or -1 on failure. 2559 */ 2560 static int 2561 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2562 int flags, RtldLockState *lockstate) 2563 { 2564 2565 if (obj->relocated) 2566 return (0); 2567 obj->relocated = true; 2568 if (obj != rtldobj) 2569 dbg("relocating \"%s\"", obj->path); 2570 2571 if (obj->symtab == NULL || obj->strtab == NULL || 2572 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2573 _rtld_error("%s: Shared object has no run-time symbol table", 2574 obj->path); 2575 return (-1); 2576 } 2577 2578 if (obj->textrel) { 2579 /* There are relocations to the write-protected text segment. */ 2580 if (mprotect(obj->mapbase, obj->textsize, 2581 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2582 _rtld_error("%s: Cannot write-enable text segment: %s", 2583 obj->path, rtld_strerror(errno)); 2584 return (-1); 2585 } 2586 } 2587 2588 /* Process the non-PLT non-IFUNC relocations. */ 2589 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2590 return (-1); 2591 2592 if (obj->textrel) { /* Re-protected the text segment. */ 2593 if (mprotect(obj->mapbase, obj->textsize, 2594 PROT_READ|PROT_EXEC) == -1) { 2595 _rtld_error("%s: Cannot write-protect text segment: %s", 2596 obj->path, rtld_strerror(errno)); 2597 return (-1); 2598 } 2599 } 2600 2601 /* Set the special PLT or GOT entries. */ 2602 init_pltgot(obj); 2603 2604 /* Process the PLT relocations. */ 2605 if (reloc_plt(obj) == -1) 2606 return (-1); 2607 /* Relocate the jump slots if we are doing immediate binding. */ 2608 if (obj->bind_now || bind_now) 2609 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2610 return (-1); 2611 2612 /* 2613 * Process the non-PLT IFUNC relocations. The relocations are 2614 * processed in two phases, because IFUNC resolvers may 2615 * reference other symbols, which must be readily processed 2616 * before resolvers are called. 2617 */ 2618 if (obj->non_plt_gnu_ifunc && 2619 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2620 return (-1); 2621 2622 if (obj->relro_size > 0) { 2623 if (mprotect(obj->relro_page, obj->relro_size, 2624 PROT_READ) == -1) { 2625 _rtld_error("%s: Cannot enforce relro protection: %s", 2626 obj->path, rtld_strerror(errno)); 2627 return (-1); 2628 } 2629 } 2630 2631 /* 2632 * Set up the magic number and version in the Obj_Entry. These 2633 * were checked in the crt1.o from the original ElfKit, so we 2634 * set them for backward compatibility. 2635 */ 2636 obj->magic = RTLD_MAGIC; 2637 obj->version = RTLD_VERSION; 2638 2639 return (0); 2640 } 2641 2642 /* 2643 * Relocate newly-loaded shared objects. The argument is a pointer to 2644 * the Obj_Entry for the first such object. All objects from the first 2645 * to the end of the list of objects are relocated. Returns 0 on success, 2646 * or -1 on failure. 2647 */ 2648 static int 2649 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2650 int flags, RtldLockState *lockstate) 2651 { 2652 Obj_Entry *obj; 2653 int error; 2654 2655 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2656 error = relocate_object(obj, bind_now, rtldobj, flags, 2657 lockstate); 2658 if (error == -1) 2659 break; 2660 } 2661 return (error); 2662 } 2663 2664 /* 2665 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2666 * referencing STT_GNU_IFUNC symbols is postponed till the other 2667 * relocations are done. The indirect functions specified as 2668 * ifunc are allowed to call other symbols, so we need to have 2669 * objects relocated before asking for resolution from indirects. 2670 * 2671 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2672 * instead of the usual lazy handling of PLT slots. It is 2673 * consistent with how GNU does it. 2674 */ 2675 static int 2676 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2677 RtldLockState *lockstate) 2678 { 2679 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2680 return (-1); 2681 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2682 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2683 return (-1); 2684 return (0); 2685 } 2686 2687 static int 2688 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2689 RtldLockState *lockstate) 2690 { 2691 Obj_Entry *obj; 2692 2693 for (obj = first; obj != NULL; obj = obj->next) { 2694 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2695 return (-1); 2696 } 2697 return (0); 2698 } 2699 2700 static int 2701 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2702 RtldLockState *lockstate) 2703 { 2704 Objlist_Entry *elm; 2705 2706 STAILQ_FOREACH(elm, list, link) { 2707 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2708 lockstate) == -1) 2709 return (-1); 2710 } 2711 return (0); 2712 } 2713 2714 /* 2715 * Cleanup procedure. It will be called (by the atexit mechanism) just 2716 * before the process exits. 2717 */ 2718 static void 2719 rtld_exit(void) 2720 { 2721 RtldLockState lockstate; 2722 2723 wlock_acquire(rtld_bind_lock, &lockstate); 2724 dbg("rtld_exit()"); 2725 objlist_call_fini(&list_fini, NULL, &lockstate); 2726 /* No need to remove the items from the list, since we are exiting. */ 2727 if (!libmap_disable) 2728 lm_fini(); 2729 lock_release(rtld_bind_lock, &lockstate); 2730 } 2731 2732 /* 2733 * Iterate over a search path, translate each element, and invoke the 2734 * callback on the result. 2735 */ 2736 static void * 2737 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2738 { 2739 const char *trans; 2740 if (path == NULL) 2741 return (NULL); 2742 2743 path += strspn(path, ":;"); 2744 while (*path != '\0') { 2745 size_t len; 2746 char *res; 2747 2748 len = strcspn(path, ":;"); 2749 trans = lm_findn(NULL, path, len); 2750 if (trans) 2751 res = callback(trans, strlen(trans), arg); 2752 else 2753 res = callback(path, len, arg); 2754 2755 if (res != NULL) 2756 return (res); 2757 2758 path += len; 2759 path += strspn(path, ":;"); 2760 } 2761 2762 return (NULL); 2763 } 2764 2765 struct try_library_args { 2766 const char *name; 2767 size_t namelen; 2768 char *buffer; 2769 size_t buflen; 2770 }; 2771 2772 static void * 2773 try_library_path(const char *dir, size_t dirlen, void *param) 2774 { 2775 struct try_library_args *arg; 2776 2777 arg = param; 2778 if (*dir == '/' || trust) { 2779 char *pathname; 2780 2781 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2782 return (NULL); 2783 2784 pathname = arg->buffer; 2785 strncpy(pathname, dir, dirlen); 2786 pathname[dirlen] = '/'; 2787 strcpy(pathname + dirlen + 1, arg->name); 2788 2789 dbg(" Trying \"%s\"", pathname); 2790 if (access(pathname, F_OK) == 0) { /* We found it */ 2791 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2792 strcpy(pathname, arg->buffer); 2793 return (pathname); 2794 } 2795 } 2796 return (NULL); 2797 } 2798 2799 static char * 2800 search_library_path(const char *name, const char *path) 2801 { 2802 char *p; 2803 struct try_library_args arg; 2804 2805 if (path == NULL) 2806 return NULL; 2807 2808 arg.name = name; 2809 arg.namelen = strlen(name); 2810 arg.buffer = xmalloc(PATH_MAX); 2811 arg.buflen = PATH_MAX; 2812 2813 p = path_enumerate(path, try_library_path, &arg); 2814 2815 free(arg.buffer); 2816 2817 return (p); 2818 } 2819 2820 2821 /* 2822 * Finds the library with the given name using the directory descriptors 2823 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2824 * 2825 * Returns a freshly-opened close-on-exec file descriptor for the library, 2826 * or -1 if the library cannot be found. 2827 */ 2828 static char * 2829 search_library_pathfds(const char *name, const char *path, int *fdp) 2830 { 2831 char *envcopy, *fdstr, *found, *last_token; 2832 size_t len; 2833 int dirfd, fd; 2834 2835 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2836 2837 /* Don't load from user-specified libdirs into setuid binaries. */ 2838 if (!trust) 2839 return (NULL); 2840 2841 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2842 if (path == NULL) 2843 return (NULL); 2844 2845 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2846 if (name[0] == '/') { 2847 dbg("Absolute path (%s) passed to %s", name, __func__); 2848 return (NULL); 2849 } 2850 2851 /* 2852 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2853 * copy of the path, as strtok_r rewrites separator tokens 2854 * with '\0'. 2855 */ 2856 found = NULL; 2857 envcopy = xstrdup(path); 2858 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2859 fdstr = strtok_r(NULL, ":", &last_token)) { 2860 dirfd = parse_libdir(fdstr); 2861 if (dirfd < 0) 2862 break; 2863 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2864 if (fd >= 0) { 2865 *fdp = fd; 2866 len = strlen(fdstr) + strlen(name) + 3; 2867 found = xmalloc(len); 2868 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2869 _rtld_error("error generating '%d/%s'", 2870 dirfd, name); 2871 rtld_die(); 2872 } 2873 dbg("open('%s') => %d", found, fd); 2874 break; 2875 } 2876 } 2877 free(envcopy); 2878 2879 return (found); 2880 } 2881 2882 2883 int 2884 dlclose(void *handle) 2885 { 2886 Obj_Entry *root; 2887 RtldLockState lockstate; 2888 2889 wlock_acquire(rtld_bind_lock, &lockstate); 2890 root = dlcheck(handle); 2891 if (root == NULL) { 2892 lock_release(rtld_bind_lock, &lockstate); 2893 return -1; 2894 } 2895 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2896 root->path); 2897 2898 /* Unreference the object and its dependencies. */ 2899 root->dl_refcount--; 2900 2901 if (root->refcount == 1) { 2902 /* 2903 * The object will be no longer referenced, so we must unload it. 2904 * First, call the fini functions. 2905 */ 2906 objlist_call_fini(&list_fini, root, &lockstate); 2907 2908 unref_dag(root); 2909 2910 /* Finish cleaning up the newly-unreferenced objects. */ 2911 GDB_STATE(RT_DELETE,&root->linkmap); 2912 unload_object(root); 2913 GDB_STATE(RT_CONSISTENT,NULL); 2914 } else 2915 unref_dag(root); 2916 2917 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2918 lock_release(rtld_bind_lock, &lockstate); 2919 return 0; 2920 } 2921 2922 char * 2923 dlerror(void) 2924 { 2925 char *msg = error_message; 2926 error_message = NULL; 2927 return msg; 2928 } 2929 2930 /* 2931 * This function is deprecated and has no effect. 2932 */ 2933 void 2934 dllockinit(void *context, 2935 void *(*lock_create)(void *context), 2936 void (*rlock_acquire)(void *lock), 2937 void (*wlock_acquire)(void *lock), 2938 void (*lock_release)(void *lock), 2939 void (*lock_destroy)(void *lock), 2940 void (*context_destroy)(void *context)) 2941 { 2942 static void *cur_context; 2943 static void (*cur_context_destroy)(void *); 2944 2945 /* Just destroy the context from the previous call, if necessary. */ 2946 if (cur_context_destroy != NULL) 2947 cur_context_destroy(cur_context); 2948 cur_context = context; 2949 cur_context_destroy = context_destroy; 2950 } 2951 2952 void * 2953 dlopen(const char *name, int mode) 2954 { 2955 2956 return (rtld_dlopen(name, -1, mode)); 2957 } 2958 2959 void * 2960 fdlopen(int fd, int mode) 2961 { 2962 2963 return (rtld_dlopen(NULL, fd, mode)); 2964 } 2965 2966 static void * 2967 rtld_dlopen(const char *name, int fd, int mode) 2968 { 2969 RtldLockState lockstate; 2970 int lo_flags; 2971 2972 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2973 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2974 if (ld_tracing != NULL) { 2975 rlock_acquire(rtld_bind_lock, &lockstate); 2976 if (sigsetjmp(lockstate.env, 0) != 0) 2977 lock_upgrade(rtld_bind_lock, &lockstate); 2978 environ = (char **)*get_program_var_addr("environ", &lockstate); 2979 lock_release(rtld_bind_lock, &lockstate); 2980 } 2981 lo_flags = RTLD_LO_DLOPEN; 2982 if (mode & RTLD_NODELETE) 2983 lo_flags |= RTLD_LO_NODELETE; 2984 if (mode & RTLD_NOLOAD) 2985 lo_flags |= RTLD_LO_NOLOAD; 2986 if (ld_tracing != NULL) 2987 lo_flags |= RTLD_LO_TRACE; 2988 2989 return (dlopen_object(name, fd, obj_main, lo_flags, 2990 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2991 } 2992 2993 static void 2994 dlopen_cleanup(Obj_Entry *obj) 2995 { 2996 2997 obj->dl_refcount--; 2998 unref_dag(obj); 2999 if (obj->refcount == 0) 3000 unload_object(obj); 3001 } 3002 3003 static Obj_Entry * 3004 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3005 int mode, RtldLockState *lockstate) 3006 { 3007 Obj_Entry **old_obj_tail; 3008 Obj_Entry *obj; 3009 Objlist initlist; 3010 RtldLockState mlockstate; 3011 int result; 3012 3013 objlist_init(&initlist); 3014 3015 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3016 wlock_acquire(rtld_bind_lock, &mlockstate); 3017 lockstate = &mlockstate; 3018 } 3019 GDB_STATE(RT_ADD,NULL); 3020 3021 old_obj_tail = obj_tail; 3022 obj = NULL; 3023 if (name == NULL && fd == -1) { 3024 obj = obj_main; 3025 obj->refcount++; 3026 } else { 3027 obj = load_object(name, fd, refobj, lo_flags); 3028 } 3029 3030 if (obj) { 3031 obj->dl_refcount++; 3032 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3033 objlist_push_tail(&list_global, obj); 3034 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3035 assert(*old_obj_tail == obj); 3036 result = load_needed_objects(obj, 3037 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3038 init_dag(obj); 3039 ref_dag(obj); 3040 if (result != -1) 3041 result = rtld_verify_versions(&obj->dagmembers); 3042 if (result != -1 && ld_tracing) 3043 goto trace; 3044 if (result == -1 || relocate_object_dag(obj, 3045 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3046 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3047 lockstate) == -1) { 3048 dlopen_cleanup(obj); 3049 obj = NULL; 3050 } else if (lo_flags & RTLD_LO_EARLY) { 3051 /* 3052 * Do not call the init functions for early loaded 3053 * filtees. The image is still not initialized enough 3054 * for them to work. 3055 * 3056 * Our object is found by the global object list and 3057 * will be ordered among all init calls done right 3058 * before transferring control to main. 3059 */ 3060 } else { 3061 /* Make list of init functions to call. */ 3062 initlist_add_objects(obj, &obj->next, &initlist); 3063 } 3064 /* 3065 * Process all no_delete or global objects here, given 3066 * them own DAGs to prevent their dependencies from being 3067 * unloaded. This has to be done after we have loaded all 3068 * of the dependencies, so that we do not miss any. 3069 */ 3070 if (obj != NULL) 3071 process_z(obj); 3072 } else { 3073 /* 3074 * Bump the reference counts for objects on this DAG. If 3075 * this is the first dlopen() call for the object that was 3076 * already loaded as a dependency, initialize the dag 3077 * starting at it. 3078 */ 3079 init_dag(obj); 3080 ref_dag(obj); 3081 3082 if ((lo_flags & RTLD_LO_TRACE) != 0) 3083 goto trace; 3084 } 3085 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3086 obj->z_nodelete) && !obj->ref_nodel) { 3087 dbg("obj %s nodelete", obj->path); 3088 ref_dag(obj); 3089 obj->z_nodelete = obj->ref_nodel = true; 3090 } 3091 } 3092 3093 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3094 name); 3095 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3096 3097 if (!(lo_flags & RTLD_LO_EARLY)) { 3098 map_stacks_exec(lockstate); 3099 } 3100 3101 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3102 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3103 lockstate) == -1) { 3104 objlist_clear(&initlist); 3105 dlopen_cleanup(obj); 3106 if (lockstate == &mlockstate) 3107 lock_release(rtld_bind_lock, lockstate); 3108 return (NULL); 3109 } 3110 3111 if (!(lo_flags & RTLD_LO_EARLY)) { 3112 /* Call the init functions. */ 3113 objlist_call_init(&initlist, lockstate); 3114 } 3115 objlist_clear(&initlist); 3116 if (lockstate == &mlockstate) 3117 lock_release(rtld_bind_lock, lockstate); 3118 return obj; 3119 trace: 3120 trace_loaded_objects(obj); 3121 if (lockstate == &mlockstate) 3122 lock_release(rtld_bind_lock, lockstate); 3123 exit(0); 3124 } 3125 3126 static void * 3127 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3128 int flags) 3129 { 3130 DoneList donelist; 3131 const Obj_Entry *obj, *defobj; 3132 const Elf_Sym *def; 3133 SymLook req; 3134 RtldLockState lockstate; 3135 tls_index ti; 3136 void *sym; 3137 int res; 3138 3139 def = NULL; 3140 defobj = NULL; 3141 symlook_init(&req, name); 3142 req.ventry = ve; 3143 req.flags = flags | SYMLOOK_IN_PLT; 3144 req.lockstate = &lockstate; 3145 3146 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3147 rlock_acquire(rtld_bind_lock, &lockstate); 3148 if (sigsetjmp(lockstate.env, 0) != 0) 3149 lock_upgrade(rtld_bind_lock, &lockstate); 3150 if (handle == NULL || handle == RTLD_NEXT || 3151 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3152 3153 if ((obj = obj_from_addr(retaddr)) == NULL) { 3154 _rtld_error("Cannot determine caller's shared object"); 3155 lock_release(rtld_bind_lock, &lockstate); 3156 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3157 return NULL; 3158 } 3159 if (handle == NULL) { /* Just the caller's shared object. */ 3160 res = symlook_obj(&req, obj); 3161 if (res == 0) { 3162 def = req.sym_out; 3163 defobj = req.defobj_out; 3164 } 3165 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3166 handle == RTLD_SELF) { /* ... caller included */ 3167 if (handle == RTLD_NEXT) 3168 obj = obj->next; 3169 for (; obj != NULL; obj = obj->next) { 3170 res = symlook_obj(&req, obj); 3171 if (res == 0) { 3172 if (def == NULL || 3173 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3174 def = req.sym_out; 3175 defobj = req.defobj_out; 3176 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3177 break; 3178 } 3179 } 3180 } 3181 /* 3182 * Search the dynamic linker itself, and possibly resolve the 3183 * symbol from there. This is how the application links to 3184 * dynamic linker services such as dlopen. 3185 */ 3186 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3187 res = symlook_obj(&req, &obj_rtld); 3188 if (res == 0) { 3189 def = req.sym_out; 3190 defobj = req.defobj_out; 3191 } 3192 } 3193 } else { 3194 assert(handle == RTLD_DEFAULT); 3195 res = symlook_default(&req, obj); 3196 if (res == 0) { 3197 defobj = req.defobj_out; 3198 def = req.sym_out; 3199 } 3200 } 3201 } else { 3202 if ((obj = dlcheck(handle)) == NULL) { 3203 lock_release(rtld_bind_lock, &lockstate); 3204 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3205 return NULL; 3206 } 3207 3208 donelist_init(&donelist); 3209 if (obj->mainprog) { 3210 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3211 res = symlook_global(&req, &donelist); 3212 if (res == 0) { 3213 def = req.sym_out; 3214 defobj = req.defobj_out; 3215 } 3216 /* 3217 * Search the dynamic linker itself, and possibly resolve the 3218 * symbol from there. This is how the application links to 3219 * dynamic linker services such as dlopen. 3220 */ 3221 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3222 res = symlook_obj(&req, &obj_rtld); 3223 if (res == 0) { 3224 def = req.sym_out; 3225 defobj = req.defobj_out; 3226 } 3227 } 3228 } 3229 else { 3230 /* Search the whole DAG rooted at the given object. */ 3231 res = symlook_list(&req, &obj->dagmembers, &donelist); 3232 if (res == 0) { 3233 def = req.sym_out; 3234 defobj = req.defobj_out; 3235 } 3236 } 3237 } 3238 3239 if (def != NULL) { 3240 lock_release(rtld_bind_lock, &lockstate); 3241 3242 /* 3243 * The value required by the caller is derived from the value 3244 * of the symbol. this is simply the relocated value of the 3245 * symbol. 3246 */ 3247 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3248 sym = make_function_pointer(def, defobj); 3249 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3250 sym = rtld_resolve_ifunc(defobj, def); 3251 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3252 ti.ti_module = defobj->tlsindex; 3253 ti.ti_offset = def->st_value; 3254 sym = __tls_get_addr(&ti); 3255 } else 3256 sym = defobj->relocbase + def->st_value; 3257 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3258 return (sym); 3259 } 3260 3261 _rtld_error("Undefined symbol \"%s\"", name); 3262 lock_release(rtld_bind_lock, &lockstate); 3263 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3264 return NULL; 3265 } 3266 3267 void * 3268 dlsym(void *handle, const char *name) 3269 { 3270 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3271 SYMLOOK_DLSYM); 3272 } 3273 3274 dlfunc_t 3275 dlfunc(void *handle, const char *name) 3276 { 3277 union { 3278 void *d; 3279 dlfunc_t f; 3280 } rv; 3281 3282 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3283 SYMLOOK_DLSYM); 3284 return (rv.f); 3285 } 3286 3287 void * 3288 dlvsym(void *handle, const char *name, const char *version) 3289 { 3290 Ver_Entry ventry; 3291 3292 ventry.name = version; 3293 ventry.file = NULL; 3294 ventry.hash = elf_hash(version); 3295 ventry.flags= 0; 3296 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3297 SYMLOOK_DLSYM); 3298 } 3299 3300 int 3301 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3302 { 3303 const Obj_Entry *obj; 3304 RtldLockState lockstate; 3305 3306 rlock_acquire(rtld_bind_lock, &lockstate); 3307 obj = obj_from_addr(addr); 3308 if (obj == NULL) { 3309 _rtld_error("No shared object contains address"); 3310 lock_release(rtld_bind_lock, &lockstate); 3311 return (0); 3312 } 3313 rtld_fill_dl_phdr_info(obj, phdr_info); 3314 lock_release(rtld_bind_lock, &lockstate); 3315 return (1); 3316 } 3317 3318 int 3319 dladdr(const void *addr, Dl_info *info) 3320 { 3321 const Obj_Entry *obj; 3322 const Elf_Sym *def; 3323 void *symbol_addr; 3324 unsigned long symoffset; 3325 RtldLockState lockstate; 3326 3327 rlock_acquire(rtld_bind_lock, &lockstate); 3328 obj = obj_from_addr(addr); 3329 if (obj == NULL) { 3330 _rtld_error("No shared object contains address"); 3331 lock_release(rtld_bind_lock, &lockstate); 3332 return 0; 3333 } 3334 info->dli_fname = obj->path; 3335 info->dli_fbase = obj->mapbase; 3336 info->dli_saddr = (void *)0; 3337 info->dli_sname = NULL; 3338 3339 /* 3340 * Walk the symbol list looking for the symbol whose address is 3341 * closest to the address sent in. 3342 */ 3343 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3344 def = obj->symtab + symoffset; 3345 3346 /* 3347 * For skip the symbol if st_shndx is either SHN_UNDEF or 3348 * SHN_COMMON. 3349 */ 3350 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3351 continue; 3352 3353 /* 3354 * If the symbol is greater than the specified address, or if it 3355 * is further away from addr than the current nearest symbol, 3356 * then reject it. 3357 */ 3358 symbol_addr = obj->relocbase + def->st_value; 3359 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3360 continue; 3361 3362 /* Update our idea of the nearest symbol. */ 3363 info->dli_sname = obj->strtab + def->st_name; 3364 info->dli_saddr = symbol_addr; 3365 3366 /* Exact match? */ 3367 if (info->dli_saddr == addr) 3368 break; 3369 } 3370 lock_release(rtld_bind_lock, &lockstate); 3371 return 1; 3372 } 3373 3374 int 3375 dlinfo(void *handle, int request, void *p) 3376 { 3377 const Obj_Entry *obj; 3378 RtldLockState lockstate; 3379 int error; 3380 3381 rlock_acquire(rtld_bind_lock, &lockstate); 3382 3383 if (handle == NULL || handle == RTLD_SELF) { 3384 void *retaddr; 3385 3386 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3387 if ((obj = obj_from_addr(retaddr)) == NULL) 3388 _rtld_error("Cannot determine caller's shared object"); 3389 } else 3390 obj = dlcheck(handle); 3391 3392 if (obj == NULL) { 3393 lock_release(rtld_bind_lock, &lockstate); 3394 return (-1); 3395 } 3396 3397 error = 0; 3398 switch (request) { 3399 case RTLD_DI_LINKMAP: 3400 *((struct link_map const **)p) = &obj->linkmap; 3401 break; 3402 case RTLD_DI_ORIGIN: 3403 error = rtld_dirname(obj->path, p); 3404 break; 3405 3406 case RTLD_DI_SERINFOSIZE: 3407 case RTLD_DI_SERINFO: 3408 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3409 break; 3410 3411 default: 3412 _rtld_error("Invalid request %d passed to dlinfo()", request); 3413 error = -1; 3414 } 3415 3416 lock_release(rtld_bind_lock, &lockstate); 3417 3418 return (error); 3419 } 3420 3421 static void 3422 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3423 { 3424 3425 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3426 phdr_info->dlpi_name = obj->path; 3427 phdr_info->dlpi_phdr = obj->phdr; 3428 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3429 phdr_info->dlpi_tls_modid = obj->tlsindex; 3430 phdr_info->dlpi_tls_data = obj->tlsinit; 3431 phdr_info->dlpi_adds = obj_loads; 3432 phdr_info->dlpi_subs = obj_loads - obj_count; 3433 } 3434 3435 int 3436 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3437 { 3438 struct dl_phdr_info phdr_info; 3439 const Obj_Entry *obj; 3440 RtldLockState bind_lockstate, phdr_lockstate; 3441 int error; 3442 3443 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3444 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3445 3446 error = 0; 3447 3448 for (obj = obj_list; obj != NULL; obj = obj->next) { 3449 rtld_fill_dl_phdr_info(obj, &phdr_info); 3450 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3451 break; 3452 3453 } 3454 if (error == 0) { 3455 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3456 error = callback(&phdr_info, sizeof(phdr_info), param); 3457 } 3458 3459 lock_release(rtld_bind_lock, &bind_lockstate); 3460 lock_release(rtld_phdr_lock, &phdr_lockstate); 3461 3462 return (error); 3463 } 3464 3465 static void * 3466 fill_search_info(const char *dir, size_t dirlen, void *param) 3467 { 3468 struct fill_search_info_args *arg; 3469 3470 arg = param; 3471 3472 if (arg->request == RTLD_DI_SERINFOSIZE) { 3473 arg->serinfo->dls_cnt ++; 3474 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3475 } else { 3476 struct dl_serpath *s_entry; 3477 3478 s_entry = arg->serpath; 3479 s_entry->dls_name = arg->strspace; 3480 s_entry->dls_flags = arg->flags; 3481 3482 strncpy(arg->strspace, dir, dirlen); 3483 arg->strspace[dirlen] = '\0'; 3484 3485 arg->strspace += dirlen + 1; 3486 arg->serpath++; 3487 } 3488 3489 return (NULL); 3490 } 3491 3492 static int 3493 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3494 { 3495 struct dl_serinfo _info; 3496 struct fill_search_info_args args; 3497 3498 args.request = RTLD_DI_SERINFOSIZE; 3499 args.serinfo = &_info; 3500 3501 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3502 _info.dls_cnt = 0; 3503 3504 path_enumerate(obj->rpath, fill_search_info, &args); 3505 path_enumerate(ld_library_path, fill_search_info, &args); 3506 path_enumerate(obj->runpath, fill_search_info, &args); 3507 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3508 if (!obj->z_nodeflib) 3509 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3510 3511 3512 if (request == RTLD_DI_SERINFOSIZE) { 3513 info->dls_size = _info.dls_size; 3514 info->dls_cnt = _info.dls_cnt; 3515 return (0); 3516 } 3517 3518 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3519 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3520 return (-1); 3521 } 3522 3523 args.request = RTLD_DI_SERINFO; 3524 args.serinfo = info; 3525 args.serpath = &info->dls_serpath[0]; 3526 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3527 3528 args.flags = LA_SER_RUNPATH; 3529 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3530 return (-1); 3531 3532 args.flags = LA_SER_LIBPATH; 3533 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3534 return (-1); 3535 3536 args.flags = LA_SER_RUNPATH; 3537 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3538 return (-1); 3539 3540 args.flags = LA_SER_CONFIG; 3541 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3542 != NULL) 3543 return (-1); 3544 3545 args.flags = LA_SER_DEFAULT; 3546 if (!obj->z_nodeflib && 3547 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3548 return (-1); 3549 return (0); 3550 } 3551 3552 static int 3553 rtld_dirname(const char *path, char *bname) 3554 { 3555 const char *endp; 3556 3557 /* Empty or NULL string gets treated as "." */ 3558 if (path == NULL || *path == '\0') { 3559 bname[0] = '.'; 3560 bname[1] = '\0'; 3561 return (0); 3562 } 3563 3564 /* Strip trailing slashes */ 3565 endp = path + strlen(path) - 1; 3566 while (endp > path && *endp == '/') 3567 endp--; 3568 3569 /* Find the start of the dir */ 3570 while (endp > path && *endp != '/') 3571 endp--; 3572 3573 /* Either the dir is "/" or there are no slashes */ 3574 if (endp == path) { 3575 bname[0] = *endp == '/' ? '/' : '.'; 3576 bname[1] = '\0'; 3577 return (0); 3578 } else { 3579 do { 3580 endp--; 3581 } while (endp > path && *endp == '/'); 3582 } 3583 3584 if (endp - path + 2 > PATH_MAX) 3585 { 3586 _rtld_error("Filename is too long: %s", path); 3587 return(-1); 3588 } 3589 3590 strncpy(bname, path, endp - path + 1); 3591 bname[endp - path + 1] = '\0'; 3592 return (0); 3593 } 3594 3595 static int 3596 rtld_dirname_abs(const char *path, char *base) 3597 { 3598 char *last; 3599 3600 if (realpath(path, base) == NULL) 3601 return (-1); 3602 dbg("%s -> %s", path, base); 3603 last = strrchr(base, '/'); 3604 if (last == NULL) 3605 return (-1); 3606 if (last != base) 3607 *last = '\0'; 3608 return (0); 3609 } 3610 3611 static void 3612 linkmap_add(Obj_Entry *obj) 3613 { 3614 struct link_map *l = &obj->linkmap; 3615 struct link_map *prev; 3616 3617 obj->linkmap.l_name = obj->path; 3618 obj->linkmap.l_addr = obj->mapbase; 3619 obj->linkmap.l_ld = obj->dynamic; 3620 #ifdef __mips__ 3621 /* GDB needs load offset on MIPS to use the symbols */ 3622 obj->linkmap.l_offs = obj->relocbase; 3623 #endif 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 __compiler_membar(); 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 __compiler_membar(); 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 * Given a symbol name in a referencing object, find the corresponding 3786 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3787 * no definition was found. Returns a pointer to the Obj_Entry of the 3788 * defining object via the reference parameter DEFOBJ_OUT. 3789 */ 3790 static int 3791 symlook_default(SymLook *req, const Obj_Entry *refobj) 3792 { 3793 DoneList donelist; 3794 const Objlist_Entry *elm; 3795 SymLook req1; 3796 int res; 3797 3798 donelist_init(&donelist); 3799 symlook_init_from_req(&req1, req); 3800 3801 /* Look first in the referencing object if linked symbolically. */ 3802 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3803 res = symlook_obj(&req1, refobj); 3804 if (res == 0) { 3805 req->sym_out = req1.sym_out; 3806 req->defobj_out = req1.defobj_out; 3807 assert(req->defobj_out != NULL); 3808 } 3809 } 3810 3811 symlook_global(req, &donelist); 3812 3813 /* Search all dlopened DAGs containing the referencing object. */ 3814 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3815 if (req->sym_out != NULL && 3816 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3817 break; 3818 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3819 if (res == 0 && (req->sym_out == NULL || 3820 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3821 req->sym_out = req1.sym_out; 3822 req->defobj_out = req1.defobj_out; 3823 assert(req->defobj_out != NULL); 3824 } 3825 } 3826 3827 /* 3828 * Search the dynamic linker itself, and possibly resolve the 3829 * symbol from there. This is how the application links to 3830 * dynamic linker services such as dlopen. 3831 */ 3832 if (req->sym_out == NULL || 3833 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3834 res = symlook_obj(&req1, &obj_rtld); 3835 if (res == 0) { 3836 req->sym_out = req1.sym_out; 3837 req->defobj_out = req1.defobj_out; 3838 assert(req->defobj_out != NULL); 3839 } 3840 } 3841 3842 return (req->sym_out != NULL ? 0 : ESRCH); 3843 } 3844 3845 static int 3846 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3847 { 3848 const Elf_Sym *def; 3849 const Obj_Entry *defobj; 3850 const Objlist_Entry *elm; 3851 SymLook req1; 3852 int res; 3853 3854 def = NULL; 3855 defobj = NULL; 3856 STAILQ_FOREACH(elm, objlist, link) { 3857 if (donelist_check(dlp, elm->obj)) 3858 continue; 3859 symlook_init_from_req(&req1, req); 3860 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3861 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3862 def = req1.sym_out; 3863 defobj = req1.defobj_out; 3864 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3865 break; 3866 } 3867 } 3868 } 3869 if (def != NULL) { 3870 req->sym_out = def; 3871 req->defobj_out = defobj; 3872 return (0); 3873 } 3874 return (ESRCH); 3875 } 3876 3877 /* 3878 * Search the chain of DAGS cointed to by the given Needed_Entry 3879 * for a symbol of the given name. Each DAG is scanned completely 3880 * before advancing to the next one. Returns a pointer to the symbol, 3881 * or NULL if no definition was found. 3882 */ 3883 static int 3884 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3885 { 3886 const Elf_Sym *def; 3887 const Needed_Entry *n; 3888 const Obj_Entry *defobj; 3889 SymLook req1; 3890 int res; 3891 3892 def = NULL; 3893 defobj = NULL; 3894 symlook_init_from_req(&req1, req); 3895 for (n = needed; n != NULL; n = n->next) { 3896 if (n->obj == NULL || 3897 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3898 continue; 3899 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3900 def = req1.sym_out; 3901 defobj = req1.defobj_out; 3902 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3903 break; 3904 } 3905 } 3906 if (def != NULL) { 3907 req->sym_out = def; 3908 req->defobj_out = defobj; 3909 return (0); 3910 } 3911 return (ESRCH); 3912 } 3913 3914 /* 3915 * Search the symbol table of a single shared object for a symbol of 3916 * the given name and version, if requested. Returns a pointer to the 3917 * symbol, or NULL if no definition was found. If the object is 3918 * filter, return filtered symbol from filtee. 3919 * 3920 * The symbol's hash value is passed in for efficiency reasons; that 3921 * eliminates many recomputations of the hash value. 3922 */ 3923 int 3924 symlook_obj(SymLook *req, const Obj_Entry *obj) 3925 { 3926 DoneList donelist; 3927 SymLook req1; 3928 int flags, res, mres; 3929 3930 /* 3931 * If there is at least one valid hash at this point, we prefer to 3932 * use the faster GNU version if available. 3933 */ 3934 if (obj->valid_hash_gnu) 3935 mres = symlook_obj1_gnu(req, obj); 3936 else if (obj->valid_hash_sysv) 3937 mres = symlook_obj1_sysv(req, obj); 3938 else 3939 return (EINVAL); 3940 3941 if (mres == 0) { 3942 if (obj->needed_filtees != NULL) { 3943 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3944 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3945 donelist_init(&donelist); 3946 symlook_init_from_req(&req1, req); 3947 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3948 if (res == 0) { 3949 req->sym_out = req1.sym_out; 3950 req->defobj_out = req1.defobj_out; 3951 } 3952 return (res); 3953 } 3954 if (obj->needed_aux_filtees != NULL) { 3955 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3956 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3957 donelist_init(&donelist); 3958 symlook_init_from_req(&req1, req); 3959 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3960 if (res == 0) { 3961 req->sym_out = req1.sym_out; 3962 req->defobj_out = req1.defobj_out; 3963 return (res); 3964 } 3965 } 3966 } 3967 return (mres); 3968 } 3969 3970 /* Symbol match routine common to both hash functions */ 3971 static bool 3972 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3973 const unsigned long symnum) 3974 { 3975 Elf_Versym verndx; 3976 const Elf_Sym *symp; 3977 const char *strp; 3978 3979 symp = obj->symtab + symnum; 3980 strp = obj->strtab + symp->st_name; 3981 3982 switch (ELF_ST_TYPE(symp->st_info)) { 3983 case STT_FUNC: 3984 case STT_NOTYPE: 3985 case STT_OBJECT: 3986 case STT_COMMON: 3987 case STT_GNU_IFUNC: 3988 if (symp->st_value == 0) 3989 return (false); 3990 /* fallthrough */ 3991 case STT_TLS: 3992 if (symp->st_shndx != SHN_UNDEF) 3993 break; 3994 #ifndef __mips__ 3995 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 3996 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 3997 break; 3998 /* fallthrough */ 3999 #endif 4000 default: 4001 return (false); 4002 } 4003 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4004 return (false); 4005 4006 if (req->ventry == NULL) { 4007 if (obj->versyms != NULL) { 4008 verndx = VER_NDX(obj->versyms[symnum]); 4009 if (verndx > obj->vernum) { 4010 _rtld_error( 4011 "%s: symbol %s references wrong version %d", 4012 obj->path, obj->strtab + symnum, verndx); 4013 return (false); 4014 } 4015 /* 4016 * If we are not called from dlsym (i.e. this 4017 * is a normal relocation from unversioned 4018 * binary), accept the symbol immediately if 4019 * it happens to have first version after this 4020 * shared object became versioned. Otherwise, 4021 * if symbol is versioned and not hidden, 4022 * remember it. If it is the only symbol with 4023 * this name exported by the shared object, it 4024 * will be returned as a match by the calling 4025 * function. If symbol is global (verndx < 2) 4026 * accept it unconditionally. 4027 */ 4028 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4029 verndx == VER_NDX_GIVEN) { 4030 result->sym_out = symp; 4031 return (true); 4032 } 4033 else if (verndx >= VER_NDX_GIVEN) { 4034 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4035 == 0) { 4036 if (result->vsymp == NULL) 4037 result->vsymp = symp; 4038 result->vcount++; 4039 } 4040 return (false); 4041 } 4042 } 4043 result->sym_out = symp; 4044 return (true); 4045 } 4046 if (obj->versyms == NULL) { 4047 if (object_match_name(obj, req->ventry->name)) { 4048 _rtld_error("%s: object %s should provide version %s " 4049 "for symbol %s", obj_rtld.path, obj->path, 4050 req->ventry->name, obj->strtab + symnum); 4051 return (false); 4052 } 4053 } else { 4054 verndx = VER_NDX(obj->versyms[symnum]); 4055 if (verndx > obj->vernum) { 4056 _rtld_error("%s: symbol %s references wrong version %d", 4057 obj->path, obj->strtab + symnum, verndx); 4058 return (false); 4059 } 4060 if (obj->vertab[verndx].hash != req->ventry->hash || 4061 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4062 /* 4063 * Version does not match. Look if this is a 4064 * global symbol and if it is not hidden. If 4065 * global symbol (verndx < 2) is available, 4066 * use it. Do not return symbol if we are 4067 * called by dlvsym, because dlvsym looks for 4068 * a specific version and default one is not 4069 * what dlvsym wants. 4070 */ 4071 if ((req->flags & SYMLOOK_DLSYM) || 4072 (verndx >= VER_NDX_GIVEN) || 4073 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4074 return (false); 4075 } 4076 } 4077 result->sym_out = symp; 4078 return (true); 4079 } 4080 4081 /* 4082 * Search for symbol using SysV hash function. 4083 * obj->buckets is known not to be NULL at this point; the test for this was 4084 * performed with the obj->valid_hash_sysv assignment. 4085 */ 4086 static int 4087 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4088 { 4089 unsigned long symnum; 4090 Sym_Match_Result matchres; 4091 4092 matchres.sym_out = NULL; 4093 matchres.vsymp = NULL; 4094 matchres.vcount = 0; 4095 4096 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4097 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4098 if (symnum >= obj->nchains) 4099 return (ESRCH); /* Bad object */ 4100 4101 if (matched_symbol(req, obj, &matchres, symnum)) { 4102 req->sym_out = matchres.sym_out; 4103 req->defobj_out = obj; 4104 return (0); 4105 } 4106 } 4107 if (matchres.vcount == 1) { 4108 req->sym_out = matchres.vsymp; 4109 req->defobj_out = obj; 4110 return (0); 4111 } 4112 return (ESRCH); 4113 } 4114 4115 /* Search for symbol using GNU hash function */ 4116 static int 4117 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4118 { 4119 Elf_Addr bloom_word; 4120 const Elf32_Word *hashval; 4121 Elf32_Word bucket; 4122 Sym_Match_Result matchres; 4123 unsigned int h1, h2; 4124 unsigned long symnum; 4125 4126 matchres.sym_out = NULL; 4127 matchres.vsymp = NULL; 4128 matchres.vcount = 0; 4129 4130 /* Pick right bitmask word from Bloom filter array */ 4131 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4132 obj->maskwords_bm_gnu]; 4133 4134 /* Calculate modulus word size of gnu hash and its derivative */ 4135 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4136 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4137 4138 /* Filter out the "definitely not in set" queries */ 4139 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4140 return (ESRCH); 4141 4142 /* Locate hash chain and corresponding value element*/ 4143 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4144 if (bucket == 0) 4145 return (ESRCH); 4146 hashval = &obj->chain_zero_gnu[bucket]; 4147 do { 4148 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4149 symnum = hashval - obj->chain_zero_gnu; 4150 if (matched_symbol(req, obj, &matchres, symnum)) { 4151 req->sym_out = matchres.sym_out; 4152 req->defobj_out = obj; 4153 return (0); 4154 } 4155 } 4156 } while ((*hashval++ & 1) == 0); 4157 if (matchres.vcount == 1) { 4158 req->sym_out = matchres.vsymp; 4159 req->defobj_out = obj; 4160 return (0); 4161 } 4162 return (ESRCH); 4163 } 4164 4165 static void 4166 trace_loaded_objects(Obj_Entry *obj) 4167 { 4168 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4169 int c; 4170 4171 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4172 main_local = ""; 4173 4174 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4175 fmt1 = "\t%o => %p (%x)\n"; 4176 4177 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4178 fmt2 = "\t%o (%x)\n"; 4179 4180 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4181 4182 for (; obj; obj = obj->next) { 4183 Needed_Entry *needed; 4184 char *name, *path; 4185 bool is_lib; 4186 4187 if (list_containers && obj->needed != NULL) 4188 rtld_printf("%s:\n", obj->path); 4189 for (needed = obj->needed; needed; needed = needed->next) { 4190 if (needed->obj != NULL) { 4191 if (needed->obj->traced && !list_containers) 4192 continue; 4193 needed->obj->traced = true; 4194 path = needed->obj->path; 4195 } else 4196 path = "not found"; 4197 4198 name = (char *)obj->strtab + needed->name; 4199 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4200 4201 fmt = is_lib ? fmt1 : fmt2; 4202 while ((c = *fmt++) != '\0') { 4203 switch (c) { 4204 default: 4205 rtld_putchar(c); 4206 continue; 4207 case '\\': 4208 switch (c = *fmt) { 4209 case '\0': 4210 continue; 4211 case 'n': 4212 rtld_putchar('\n'); 4213 break; 4214 case 't': 4215 rtld_putchar('\t'); 4216 break; 4217 } 4218 break; 4219 case '%': 4220 switch (c = *fmt) { 4221 case '\0': 4222 continue; 4223 case '%': 4224 default: 4225 rtld_putchar(c); 4226 break; 4227 case 'A': 4228 rtld_putstr(main_local); 4229 break; 4230 case 'a': 4231 rtld_putstr(obj_main->path); 4232 break; 4233 case 'o': 4234 rtld_putstr(name); 4235 break; 4236 #if 0 4237 case 'm': 4238 rtld_printf("%d", sodp->sod_major); 4239 break; 4240 case 'n': 4241 rtld_printf("%d", sodp->sod_minor); 4242 break; 4243 #endif 4244 case 'p': 4245 rtld_putstr(path); 4246 break; 4247 case 'x': 4248 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4249 0); 4250 break; 4251 } 4252 break; 4253 } 4254 ++fmt; 4255 } 4256 } 4257 } 4258 } 4259 4260 /* 4261 * Unload a dlopened object and its dependencies from memory and from 4262 * our data structures. It is assumed that the DAG rooted in the 4263 * object has already been unreferenced, and that the object has a 4264 * reference count of 0. 4265 */ 4266 static void 4267 unload_object(Obj_Entry *root) 4268 { 4269 Obj_Entry *obj; 4270 Obj_Entry **linkp; 4271 4272 assert(root->refcount == 0); 4273 4274 /* 4275 * Pass over the DAG removing unreferenced objects from 4276 * appropriate lists. 4277 */ 4278 unlink_object(root); 4279 4280 /* Unmap all objects that are no longer referenced. */ 4281 linkp = &obj_list->next; 4282 while ((obj = *linkp) != NULL) { 4283 if (obj->refcount == 0) { 4284 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4285 obj->path); 4286 dbg("unloading \"%s\"", obj->path); 4287 unload_filtees(root); 4288 munmap(obj->mapbase, obj->mapsize); 4289 linkmap_delete(obj); 4290 *linkp = obj->next; 4291 obj_count--; 4292 obj_free(obj); 4293 } else 4294 linkp = &obj->next; 4295 } 4296 obj_tail = linkp; 4297 } 4298 4299 static void 4300 unlink_object(Obj_Entry *root) 4301 { 4302 Objlist_Entry *elm; 4303 4304 if (root->refcount == 0) { 4305 /* Remove the object from the RTLD_GLOBAL list. */ 4306 objlist_remove(&list_global, root); 4307 4308 /* Remove the object from all objects' DAG lists. */ 4309 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4310 objlist_remove(&elm->obj->dldags, root); 4311 if (elm->obj != root) 4312 unlink_object(elm->obj); 4313 } 4314 } 4315 } 4316 4317 static void 4318 ref_dag(Obj_Entry *root) 4319 { 4320 Objlist_Entry *elm; 4321 4322 assert(root->dag_inited); 4323 STAILQ_FOREACH(elm, &root->dagmembers, link) 4324 elm->obj->refcount++; 4325 } 4326 4327 static void 4328 unref_dag(Obj_Entry *root) 4329 { 4330 Objlist_Entry *elm; 4331 4332 assert(root->dag_inited); 4333 STAILQ_FOREACH(elm, &root->dagmembers, link) 4334 elm->obj->refcount--; 4335 } 4336 4337 /* 4338 * Common code for MD __tls_get_addr(). 4339 */ 4340 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4341 static void * 4342 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4343 { 4344 Elf_Addr *newdtv, *dtv; 4345 RtldLockState lockstate; 4346 int to_copy; 4347 4348 dtv = *dtvp; 4349 /* Check dtv generation in case new modules have arrived */ 4350 if (dtv[0] != tls_dtv_generation) { 4351 wlock_acquire(rtld_bind_lock, &lockstate); 4352 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4353 to_copy = dtv[1]; 4354 if (to_copy > tls_max_index) 4355 to_copy = tls_max_index; 4356 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4357 newdtv[0] = tls_dtv_generation; 4358 newdtv[1] = tls_max_index; 4359 free(dtv); 4360 lock_release(rtld_bind_lock, &lockstate); 4361 dtv = *dtvp = newdtv; 4362 } 4363 4364 /* Dynamically allocate module TLS if necessary */ 4365 if (dtv[index + 1] == 0) { 4366 /* Signal safe, wlock will block out signals. */ 4367 wlock_acquire(rtld_bind_lock, &lockstate); 4368 if (!dtv[index + 1]) 4369 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4370 lock_release(rtld_bind_lock, &lockstate); 4371 } 4372 return ((void *)(dtv[index + 1] + offset)); 4373 } 4374 4375 void * 4376 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4377 { 4378 Elf_Addr *dtv; 4379 4380 dtv = *dtvp; 4381 /* Check dtv generation in case new modules have arrived */ 4382 if (__predict_true(dtv[0] == tls_dtv_generation && 4383 dtv[index + 1] != 0)) 4384 return ((void *)(dtv[index + 1] + offset)); 4385 return (tls_get_addr_slow(dtvp, index, offset)); 4386 } 4387 4388 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4389 defined(__powerpc__) 4390 4391 /* 4392 * Allocate Static TLS using the Variant I method. 4393 */ 4394 void * 4395 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4396 { 4397 Obj_Entry *obj; 4398 char *tcb; 4399 Elf_Addr **tls; 4400 Elf_Addr *dtv; 4401 Elf_Addr addr; 4402 int i; 4403 4404 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4405 return (oldtcb); 4406 4407 assert(tcbsize >= TLS_TCB_SIZE); 4408 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4409 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4410 4411 if (oldtcb != NULL) { 4412 memcpy(tls, oldtcb, tls_static_space); 4413 free(oldtcb); 4414 4415 /* Adjust the DTV. */ 4416 dtv = tls[0]; 4417 for (i = 0; i < dtv[1]; i++) { 4418 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4419 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4420 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4421 } 4422 } 4423 } else { 4424 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4425 tls[0] = dtv; 4426 dtv[0] = tls_dtv_generation; 4427 dtv[1] = tls_max_index; 4428 4429 for (obj = objs; obj; obj = obj->next) { 4430 if (obj->tlsoffset > 0) { 4431 addr = (Elf_Addr)tls + obj->tlsoffset; 4432 if (obj->tlsinitsize > 0) 4433 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4434 if (obj->tlssize > obj->tlsinitsize) 4435 memset((void*) (addr + obj->tlsinitsize), 0, 4436 obj->tlssize - obj->tlsinitsize); 4437 dtv[obj->tlsindex + 1] = addr; 4438 } 4439 } 4440 } 4441 4442 return (tcb); 4443 } 4444 4445 void 4446 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4447 { 4448 Elf_Addr *dtv; 4449 Elf_Addr tlsstart, tlsend; 4450 int dtvsize, i; 4451 4452 assert(tcbsize >= TLS_TCB_SIZE); 4453 4454 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4455 tlsend = tlsstart + tls_static_space; 4456 4457 dtv = *(Elf_Addr **)tlsstart; 4458 dtvsize = dtv[1]; 4459 for (i = 0; i < dtvsize; i++) { 4460 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4461 free((void*)dtv[i+2]); 4462 } 4463 } 4464 free(dtv); 4465 free(tcb); 4466 } 4467 4468 #endif 4469 4470 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4471 4472 /* 4473 * Allocate Static TLS using the Variant II method. 4474 */ 4475 void * 4476 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4477 { 4478 Obj_Entry *obj; 4479 size_t size, ralign; 4480 char *tls; 4481 Elf_Addr *dtv, *olddtv; 4482 Elf_Addr segbase, oldsegbase, addr; 4483 int i; 4484 4485 ralign = tcbalign; 4486 if (tls_static_max_align > ralign) 4487 ralign = tls_static_max_align; 4488 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4489 4490 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4491 tls = malloc_aligned(size, ralign); 4492 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4493 4494 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4495 ((Elf_Addr*)segbase)[0] = segbase; 4496 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4497 4498 dtv[0] = tls_dtv_generation; 4499 dtv[1] = tls_max_index; 4500 4501 if (oldtls) { 4502 /* 4503 * Copy the static TLS block over whole. 4504 */ 4505 oldsegbase = (Elf_Addr) oldtls; 4506 memcpy((void *)(segbase - tls_static_space), 4507 (const void *)(oldsegbase - tls_static_space), 4508 tls_static_space); 4509 4510 /* 4511 * If any dynamic TLS blocks have been created tls_get_addr(), 4512 * move them over. 4513 */ 4514 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4515 for (i = 0; i < olddtv[1]; i++) { 4516 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4517 dtv[i+2] = olddtv[i+2]; 4518 olddtv[i+2] = 0; 4519 } 4520 } 4521 4522 /* 4523 * We assume that this block was the one we created with 4524 * allocate_initial_tls(). 4525 */ 4526 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4527 } else { 4528 for (obj = objs; obj; obj = obj->next) { 4529 if (obj->tlsoffset) { 4530 addr = segbase - obj->tlsoffset; 4531 memset((void*) (addr + obj->tlsinitsize), 4532 0, obj->tlssize - obj->tlsinitsize); 4533 if (obj->tlsinit) 4534 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4535 dtv[obj->tlsindex + 1] = addr; 4536 } 4537 } 4538 } 4539 4540 return (void*) segbase; 4541 } 4542 4543 void 4544 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4545 { 4546 Elf_Addr* dtv; 4547 size_t size, ralign; 4548 int dtvsize, i; 4549 Elf_Addr tlsstart, tlsend; 4550 4551 /* 4552 * Figure out the size of the initial TLS block so that we can 4553 * find stuff which ___tls_get_addr() allocated dynamically. 4554 */ 4555 ralign = tcbalign; 4556 if (tls_static_max_align > ralign) 4557 ralign = tls_static_max_align; 4558 size = round(tls_static_space, ralign); 4559 4560 dtv = ((Elf_Addr**)tls)[1]; 4561 dtvsize = dtv[1]; 4562 tlsend = (Elf_Addr) tls; 4563 tlsstart = tlsend - size; 4564 for (i = 0; i < dtvsize; i++) { 4565 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4566 free_aligned((void *)dtv[i + 2]); 4567 } 4568 } 4569 4570 free_aligned((void *)tlsstart); 4571 free((void*) dtv); 4572 } 4573 4574 #endif 4575 4576 /* 4577 * Allocate TLS block for module with given index. 4578 */ 4579 void * 4580 allocate_module_tls(int index) 4581 { 4582 Obj_Entry* obj; 4583 char* p; 4584 4585 for (obj = obj_list; obj; obj = obj->next) { 4586 if (obj->tlsindex == index) 4587 break; 4588 } 4589 if (!obj) { 4590 _rtld_error("Can't find module with TLS index %d", index); 4591 rtld_die(); 4592 } 4593 4594 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4595 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4596 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4597 4598 return p; 4599 } 4600 4601 bool 4602 allocate_tls_offset(Obj_Entry *obj) 4603 { 4604 size_t off; 4605 4606 if (obj->tls_done) 4607 return true; 4608 4609 if (obj->tlssize == 0) { 4610 obj->tls_done = true; 4611 return true; 4612 } 4613 4614 if (tls_last_offset == 0) 4615 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4616 else 4617 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4618 obj->tlssize, obj->tlsalign); 4619 4620 /* 4621 * If we have already fixed the size of the static TLS block, we 4622 * must stay within that size. When allocating the static TLS, we 4623 * leave a small amount of space spare to be used for dynamically 4624 * loading modules which use static TLS. 4625 */ 4626 if (tls_static_space != 0) { 4627 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4628 return false; 4629 } else if (obj->tlsalign > tls_static_max_align) { 4630 tls_static_max_align = obj->tlsalign; 4631 } 4632 4633 tls_last_offset = obj->tlsoffset = off; 4634 tls_last_size = obj->tlssize; 4635 obj->tls_done = true; 4636 4637 return true; 4638 } 4639 4640 void 4641 free_tls_offset(Obj_Entry *obj) 4642 { 4643 4644 /* 4645 * If we were the last thing to allocate out of the static TLS 4646 * block, we give our space back to the 'allocator'. This is a 4647 * simplistic workaround to allow libGL.so.1 to be loaded and 4648 * unloaded multiple times. 4649 */ 4650 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4651 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4652 tls_last_offset -= obj->tlssize; 4653 tls_last_size = 0; 4654 } 4655 } 4656 4657 void * 4658 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4659 { 4660 void *ret; 4661 RtldLockState lockstate; 4662 4663 wlock_acquire(rtld_bind_lock, &lockstate); 4664 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4665 lock_release(rtld_bind_lock, &lockstate); 4666 return (ret); 4667 } 4668 4669 void 4670 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4671 { 4672 RtldLockState lockstate; 4673 4674 wlock_acquire(rtld_bind_lock, &lockstate); 4675 free_tls(tcb, tcbsize, tcbalign); 4676 lock_release(rtld_bind_lock, &lockstate); 4677 } 4678 4679 static void 4680 object_add_name(Obj_Entry *obj, const char *name) 4681 { 4682 Name_Entry *entry; 4683 size_t len; 4684 4685 len = strlen(name); 4686 entry = malloc(sizeof(Name_Entry) + len); 4687 4688 if (entry != NULL) { 4689 strcpy(entry->name, name); 4690 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4691 } 4692 } 4693 4694 static int 4695 object_match_name(const Obj_Entry *obj, const char *name) 4696 { 4697 Name_Entry *entry; 4698 4699 STAILQ_FOREACH(entry, &obj->names, link) { 4700 if (strcmp(name, entry->name) == 0) 4701 return (1); 4702 } 4703 return (0); 4704 } 4705 4706 static Obj_Entry * 4707 locate_dependency(const Obj_Entry *obj, const char *name) 4708 { 4709 const Objlist_Entry *entry; 4710 const Needed_Entry *needed; 4711 4712 STAILQ_FOREACH(entry, &list_main, link) { 4713 if (object_match_name(entry->obj, name)) 4714 return entry->obj; 4715 } 4716 4717 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4718 if (strcmp(obj->strtab + needed->name, name) == 0 || 4719 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4720 /* 4721 * If there is DT_NEEDED for the name we are looking for, 4722 * we are all set. Note that object might not be found if 4723 * dependency was not loaded yet, so the function can 4724 * return NULL here. This is expected and handled 4725 * properly by the caller. 4726 */ 4727 return (needed->obj); 4728 } 4729 } 4730 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4731 obj->path, name); 4732 rtld_die(); 4733 } 4734 4735 static int 4736 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4737 const Elf_Vernaux *vna) 4738 { 4739 const Elf_Verdef *vd; 4740 const char *vername; 4741 4742 vername = refobj->strtab + vna->vna_name; 4743 vd = depobj->verdef; 4744 if (vd == NULL) { 4745 _rtld_error("%s: version %s required by %s not defined", 4746 depobj->path, vername, refobj->path); 4747 return (-1); 4748 } 4749 for (;;) { 4750 if (vd->vd_version != VER_DEF_CURRENT) { 4751 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4752 depobj->path, vd->vd_version); 4753 return (-1); 4754 } 4755 if (vna->vna_hash == vd->vd_hash) { 4756 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4757 ((char *)vd + vd->vd_aux); 4758 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4759 return (0); 4760 } 4761 if (vd->vd_next == 0) 4762 break; 4763 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4764 } 4765 if (vna->vna_flags & VER_FLG_WEAK) 4766 return (0); 4767 _rtld_error("%s: version %s required by %s not found", 4768 depobj->path, vername, refobj->path); 4769 return (-1); 4770 } 4771 4772 static int 4773 rtld_verify_object_versions(Obj_Entry *obj) 4774 { 4775 const Elf_Verneed *vn; 4776 const Elf_Verdef *vd; 4777 const Elf_Verdaux *vda; 4778 const Elf_Vernaux *vna; 4779 const Obj_Entry *depobj; 4780 int maxvernum, vernum; 4781 4782 if (obj->ver_checked) 4783 return (0); 4784 obj->ver_checked = true; 4785 4786 maxvernum = 0; 4787 /* 4788 * Walk over defined and required version records and figure out 4789 * max index used by any of them. Do very basic sanity checking 4790 * while there. 4791 */ 4792 vn = obj->verneed; 4793 while (vn != NULL) { 4794 if (vn->vn_version != VER_NEED_CURRENT) { 4795 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4796 obj->path, vn->vn_version); 4797 return (-1); 4798 } 4799 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4800 for (;;) { 4801 vernum = VER_NEED_IDX(vna->vna_other); 4802 if (vernum > maxvernum) 4803 maxvernum = vernum; 4804 if (vna->vna_next == 0) 4805 break; 4806 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4807 } 4808 if (vn->vn_next == 0) 4809 break; 4810 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4811 } 4812 4813 vd = obj->verdef; 4814 while (vd != NULL) { 4815 if (vd->vd_version != VER_DEF_CURRENT) { 4816 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4817 obj->path, vd->vd_version); 4818 return (-1); 4819 } 4820 vernum = VER_DEF_IDX(vd->vd_ndx); 4821 if (vernum > maxvernum) 4822 maxvernum = vernum; 4823 if (vd->vd_next == 0) 4824 break; 4825 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4826 } 4827 4828 if (maxvernum == 0) 4829 return (0); 4830 4831 /* 4832 * Store version information in array indexable by version index. 4833 * Verify that object version requirements are satisfied along the 4834 * way. 4835 */ 4836 obj->vernum = maxvernum + 1; 4837 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4838 4839 vd = obj->verdef; 4840 while (vd != NULL) { 4841 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4842 vernum = VER_DEF_IDX(vd->vd_ndx); 4843 assert(vernum <= maxvernum); 4844 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4845 obj->vertab[vernum].hash = vd->vd_hash; 4846 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4847 obj->vertab[vernum].file = NULL; 4848 obj->vertab[vernum].flags = 0; 4849 } 4850 if (vd->vd_next == 0) 4851 break; 4852 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4853 } 4854 4855 vn = obj->verneed; 4856 while (vn != NULL) { 4857 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4858 if (depobj == NULL) 4859 return (-1); 4860 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4861 for (;;) { 4862 if (check_object_provided_version(obj, depobj, vna)) 4863 return (-1); 4864 vernum = VER_NEED_IDX(vna->vna_other); 4865 assert(vernum <= maxvernum); 4866 obj->vertab[vernum].hash = vna->vna_hash; 4867 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4868 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4869 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4870 VER_INFO_HIDDEN : 0; 4871 if (vna->vna_next == 0) 4872 break; 4873 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4874 } 4875 if (vn->vn_next == 0) 4876 break; 4877 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4878 } 4879 return 0; 4880 } 4881 4882 static int 4883 rtld_verify_versions(const Objlist *objlist) 4884 { 4885 Objlist_Entry *entry; 4886 int rc; 4887 4888 rc = 0; 4889 STAILQ_FOREACH(entry, objlist, link) { 4890 /* 4891 * Skip dummy objects or objects that have their version requirements 4892 * already checked. 4893 */ 4894 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4895 continue; 4896 if (rtld_verify_object_versions(entry->obj) == -1) { 4897 rc = -1; 4898 if (ld_tracing == NULL) 4899 break; 4900 } 4901 } 4902 if (rc == 0 || ld_tracing != NULL) 4903 rc = rtld_verify_object_versions(&obj_rtld); 4904 return rc; 4905 } 4906 4907 const Ver_Entry * 4908 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4909 { 4910 Elf_Versym vernum; 4911 4912 if (obj->vertab) { 4913 vernum = VER_NDX(obj->versyms[symnum]); 4914 if (vernum >= obj->vernum) { 4915 _rtld_error("%s: symbol %s has wrong verneed value %d", 4916 obj->path, obj->strtab + symnum, vernum); 4917 } else if (obj->vertab[vernum].hash != 0) { 4918 return &obj->vertab[vernum]; 4919 } 4920 } 4921 return NULL; 4922 } 4923 4924 int 4925 _rtld_get_stack_prot(void) 4926 { 4927 4928 return (stack_prot); 4929 } 4930 4931 int 4932 _rtld_is_dlopened(void *arg) 4933 { 4934 Obj_Entry *obj; 4935 RtldLockState lockstate; 4936 int res; 4937 4938 rlock_acquire(rtld_bind_lock, &lockstate); 4939 obj = dlcheck(arg); 4940 if (obj == NULL) 4941 obj = obj_from_addr(arg); 4942 if (obj == NULL) { 4943 _rtld_error("No shared object contains address"); 4944 lock_release(rtld_bind_lock, &lockstate); 4945 return (-1); 4946 } 4947 res = obj->dlopened ? 1 : 0; 4948 lock_release(rtld_bind_lock, &lockstate); 4949 return (res); 4950 } 4951 4952 static void 4953 map_stacks_exec(RtldLockState *lockstate) 4954 { 4955 void (*thr_map_stacks_exec)(void); 4956 4957 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4958 return; 4959 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4960 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4961 if (thr_map_stacks_exec != NULL) { 4962 stack_prot |= PROT_EXEC; 4963 thr_map_stacks_exec(); 4964 } 4965 } 4966 4967 void 4968 symlook_init(SymLook *dst, const char *name) 4969 { 4970 4971 bzero(dst, sizeof(*dst)); 4972 dst->name = name; 4973 dst->hash = elf_hash(name); 4974 dst->hash_gnu = gnu_hash(name); 4975 } 4976 4977 static void 4978 symlook_init_from_req(SymLook *dst, const SymLook *src) 4979 { 4980 4981 dst->name = src->name; 4982 dst->hash = src->hash; 4983 dst->hash_gnu = src->hash_gnu; 4984 dst->ventry = src->ventry; 4985 dst->flags = src->flags; 4986 dst->defobj_out = NULL; 4987 dst->sym_out = NULL; 4988 dst->lockstate = src->lockstate; 4989 } 4990 4991 4992 /* 4993 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4994 */ 4995 static int 4996 parse_libdir(const char *str) 4997 { 4998 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 4999 const char *orig; 5000 int fd; 5001 char c; 5002 5003 orig = str; 5004 fd = 0; 5005 for (c = *str; c != '\0'; c = *++str) { 5006 if (c < '0' || c > '9') 5007 return (-1); 5008 5009 fd *= RADIX; 5010 fd += c - '0'; 5011 } 5012 5013 /* Make sure we actually parsed something. */ 5014 if (str == orig) { 5015 _rtld_error("failed to parse directory FD from '%s'", str); 5016 return (-1); 5017 } 5018 return (fd); 5019 } 5020 5021 /* 5022 * Overrides for libc_pic-provided functions. 5023 */ 5024 5025 int 5026 __getosreldate(void) 5027 { 5028 size_t len; 5029 int oid[2]; 5030 int error, osrel; 5031 5032 if (osreldate != 0) 5033 return (osreldate); 5034 5035 oid[0] = CTL_KERN; 5036 oid[1] = KERN_OSRELDATE; 5037 osrel = 0; 5038 len = sizeof(osrel); 5039 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5040 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5041 osreldate = osrel; 5042 return (osreldate); 5043 } 5044 5045 void 5046 exit(int status) 5047 { 5048 5049 _exit(status); 5050 } 5051 5052 void (*__cleanup)(void); 5053 int __isthreaded = 0; 5054 int _thread_autoinit_dummy_decl = 1; 5055 5056 /* 5057 * No unresolved symbols for rtld. 5058 */ 5059 void 5060 __pthread_cxa_finalize(struct dl_phdr_info *a) 5061 { 5062 } 5063 5064 void 5065 __stack_chk_fail(void) 5066 { 5067 5068 _rtld_error("stack overflow detected; terminated"); 5069 rtld_die(); 5070 } 5071 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5072 5073 void 5074 __chk_fail(void) 5075 { 5076 5077 _rtld_error("buffer overflow detected; terminated"); 5078 rtld_die(); 5079 } 5080 5081 const char * 5082 rtld_strerror(int errnum) 5083 { 5084 5085 if (errnum < 0 || errnum >= sys_nerr) 5086 return ("Unknown error"); 5087 return (sys_errlist[errnum]); 5088 } 5089