1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. 4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>. 5 * Copyright 2012 John Marino <draco@marino.st>. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Dynamic linker for ELF. 33 * 34 * John Polstra <jdp@polstra.com>. 35 */ 36 37 #ifndef __GNUC__ 38 #error "GCC is needed to compile this file" 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/mount.h> 43 #include <sys/mman.h> 44 #include <sys/stat.h> 45 #include <sys/sysctl.h> 46 #include <sys/uio.h> 47 #include <sys/utsname.h> 48 #include <sys/ktrace.h> 49 50 #include <dlfcn.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <fcntl.h> 54 #include <stdarg.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 #include "debug.h" 61 #include "rtld.h" 62 #include "libmap.h" 63 #include "rtld_tls.h" 64 #include "rtld_printf.h" 65 #include "notes.h" 66 67 #ifndef COMPAT_32BIT 68 #define PATH_RTLD "/libexec/ld-elf.so.1" 69 #else 70 #define PATH_RTLD "/libexec/ld-elf32.so.1" 71 #endif 72 73 /* Types. */ 74 typedef void (*func_ptr_type)(); 75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); 76 77 /* 78 * Function declarations. 79 */ 80 static const char *basename(const char *); 81 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, 82 const Elf_Dyn **, const Elf_Dyn **); 83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, 84 const Elf_Dyn *); 85 static void digest_dynamic(Obj_Entry *, int); 86 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); 87 static Obj_Entry *dlcheck(void *); 88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, 89 int lo_flags, int mode, RtldLockState *lockstate); 90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); 91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); 92 static bool donelist_check(DoneList *, const Obj_Entry *); 93 static void errmsg_restore(char *); 94 static char *errmsg_save(void); 95 static void *fill_search_info(const char *, size_t, void *); 96 static char *find_library(const char *, const Obj_Entry *, int *); 97 static const char *gethints(bool); 98 static void init_dag(Obj_Entry *); 99 static void init_pagesizes(Elf_Auxinfo **aux_info); 100 static void init_rtld(caddr_t, Elf_Auxinfo **); 101 static void initlist_add_neededs(Needed_Entry *, Objlist *); 102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *); 103 static void linkmap_add(Obj_Entry *); 104 static void linkmap_delete(Obj_Entry *); 105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *); 106 static void unload_filtees(Obj_Entry *); 107 static int load_needed_objects(Obj_Entry *, int); 108 static int load_preload_objects(void); 109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); 110 static void map_stacks_exec(RtldLockState *); 111 static Obj_Entry *obj_from_addr(const void *); 112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); 113 static void objlist_call_init(Objlist *, RtldLockState *); 114 static void objlist_clear(Objlist *); 115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); 116 static void objlist_init(Objlist *); 117 static void objlist_push_head(Objlist *, Obj_Entry *); 118 static void objlist_push_tail(Objlist *, Obj_Entry *); 119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); 120 static void objlist_remove(Objlist *, Obj_Entry *); 121 static int parse_libdir(const char *); 122 static void *path_enumerate(const char *, path_enum_proc, void *); 123 static int relocate_object_dag(Obj_Entry *root, bool bind_now, 124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); 125 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 126 int flags, RtldLockState *lockstate); 127 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, 128 RtldLockState *); 129 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now, 130 int flags, RtldLockState *lockstate); 131 static int rtld_dirname(const char *, char *); 132 static int rtld_dirname_abs(const char *, char *); 133 static void *rtld_dlopen(const char *name, int fd, int mode); 134 static void rtld_exit(void); 135 static char *search_library_path(const char *, const char *); 136 static char *search_library_pathfds(const char *, const char *, int *); 137 static const void **get_program_var_addr(const char *, RtldLockState *); 138 static void set_program_var(const char *, const void *); 139 static int symlook_default(SymLook *, const Obj_Entry *refobj); 140 static int symlook_global(SymLook *, DoneList *); 141 static void symlook_init_from_req(SymLook *, const SymLook *); 142 static int symlook_list(SymLook *, const Objlist *, DoneList *); 143 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); 144 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); 145 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); 146 static void trace_loaded_objects(Obj_Entry *); 147 static void unlink_object(Obj_Entry *); 148 static void unload_object(Obj_Entry *); 149 static void unref_dag(Obj_Entry *); 150 static void ref_dag(Obj_Entry *); 151 static char *origin_subst_one(Obj_Entry *, char *, const char *, 152 const char *, bool); 153 static char *origin_subst(Obj_Entry *, char *); 154 static bool obj_resolve_origin(Obj_Entry *obj); 155 static void preinit_main(void); 156 static int rtld_verify_versions(const Objlist *); 157 static int rtld_verify_object_versions(Obj_Entry *); 158 static void object_add_name(Obj_Entry *, const char *); 159 static int object_match_name(const Obj_Entry *, const char *); 160 static void ld_utrace_log(int, void *, void *, size_t, int, const char *); 161 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, 162 struct dl_phdr_info *phdr_info); 163 static uint32_t gnu_hash(const char *); 164 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, 165 const unsigned long); 166 167 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; 168 void _r_debug_postinit(struct link_map *) __noinline __exported; 169 170 int __sys_openat(int, const char *, int, ...); 171 172 /* 173 * Data declarations. 174 */ 175 static char *error_message; /* Message for dlerror(), or NULL */ 176 struct r_debug r_debug __exported; /* for GDB; */ 177 static bool libmap_disable; /* Disable libmap */ 178 static bool ld_loadfltr; /* Immediate filters processing */ 179 static char *libmap_override; /* Maps to use in addition to libmap.conf */ 180 static bool trust; /* False for setuid and setgid programs */ 181 static bool dangerous_ld_env; /* True if environment variables have been 182 used to affect the libraries loaded */ 183 static char *ld_bind_now; /* Environment variable for immediate binding */ 184 static char *ld_debug; /* Environment variable for debugging */ 185 static char *ld_library_path; /* Environment variable for search path */ 186 static char *ld_library_dirs; /* Environment variable for library descriptors */ 187 static char *ld_preload; /* Environment variable for libraries to 188 load first */ 189 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */ 190 static char *ld_tracing; /* Called from ldd to print libs */ 191 static char *ld_utrace; /* Use utrace() to log events. */ 192 static Obj_Entry *obj_list; /* Head of linked list of shared objects */ 193 static Obj_Entry **obj_tail; /* Link field of last object in list */ 194 static Obj_Entry *obj_main; /* The main program shared object */ 195 static Obj_Entry obj_rtld; /* The dynamic linker shared object */ 196 static unsigned int obj_count; /* Number of objects in obj_list */ 197 static unsigned int obj_loads; /* Number of objects in obj_list */ 198 199 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ 200 STAILQ_HEAD_INITIALIZER(list_global); 201 static Objlist list_main = /* Objects loaded at program startup */ 202 STAILQ_HEAD_INITIALIZER(list_main); 203 static Objlist list_fini = /* Objects needing fini() calls */ 204 STAILQ_HEAD_INITIALIZER(list_fini); 205 206 Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 207 208 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); 209 210 extern Elf_Dyn _DYNAMIC; 211 #pragma weak _DYNAMIC 212 #ifndef RTLD_IS_DYNAMIC 213 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL) 214 #endif 215 216 int dlclose(void *) __exported; 217 char *dlerror(void) __exported; 218 void *dlopen(const char *, int) __exported; 219 void *fdlopen(int, int) __exported; 220 void *dlsym(void *, const char *) __exported; 221 dlfunc_t dlfunc(void *, const char *) __exported; 222 void *dlvsym(void *, const char *, const char *) __exported; 223 int dladdr(const void *, Dl_info *) __exported; 224 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), 225 void (*)(void *), void (*)(void *), void (*)(void *)) __exported; 226 int dlinfo(void *, int , void *) __exported; 227 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; 228 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; 229 int _rtld_get_stack_prot(void) __exported; 230 int _rtld_is_dlopened(void *) __exported; 231 void _rtld_error(const char *, ...) __exported; 232 233 int npagesizes, osreldate; 234 size_t *pagesizes; 235 236 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; 237 238 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; 239 static int max_stack_flags; 240 241 /* 242 * Global declarations normally provided by crt1. The dynamic linker is 243 * not built with crt1, so we have to provide them ourselves. 244 */ 245 char *__progname; 246 char **environ; 247 248 /* 249 * Used to pass argc, argv to init functions. 250 */ 251 int main_argc; 252 char **main_argv; 253 254 /* 255 * Globals to control TLS allocation. 256 */ 257 size_t tls_last_offset; /* Static TLS offset of last module */ 258 size_t tls_last_size; /* Static TLS size of last module */ 259 size_t tls_static_space; /* Static TLS space allocated */ 260 size_t tls_static_max_align; 261 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ 262 int tls_max_index = 1; /* Largest module index allocated */ 263 264 bool ld_library_path_rpath = false; 265 266 /* 267 * Fill in a DoneList with an allocation large enough to hold all of 268 * the currently-loaded objects. Keep this as a macro since it calls 269 * alloca and we want that to occur within the scope of the caller. 270 */ 271 #define donelist_init(dlp) \ 272 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ 273 assert((dlp)->objs != NULL), \ 274 (dlp)->num_alloc = obj_count, \ 275 (dlp)->num_used = 0) 276 277 #define UTRACE_DLOPEN_START 1 278 #define UTRACE_DLOPEN_STOP 2 279 #define UTRACE_DLCLOSE_START 3 280 #define UTRACE_DLCLOSE_STOP 4 281 #define UTRACE_LOAD_OBJECT 5 282 #define UTRACE_UNLOAD_OBJECT 6 283 #define UTRACE_ADD_RUNDEP 7 284 #define UTRACE_PRELOAD_FINISHED 8 285 #define UTRACE_INIT_CALL 9 286 #define UTRACE_FINI_CALL 10 287 #define UTRACE_DLSYM_START 11 288 #define UTRACE_DLSYM_STOP 12 289 290 struct utrace_rtld { 291 char sig[4]; /* 'RTLD' */ 292 int event; 293 void *handle; 294 void *mapbase; /* Used for 'parent' and 'init/fini' */ 295 size_t mapsize; 296 int refcnt; /* Used for 'mode' */ 297 char name[MAXPATHLEN]; 298 }; 299 300 #define LD_UTRACE(e, h, mb, ms, r, n) do { \ 301 if (ld_utrace != NULL) \ 302 ld_utrace_log(e, h, mb, ms, r, n); \ 303 } while (0) 304 305 static void 306 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, 307 int refcnt, const char *name) 308 { 309 struct utrace_rtld ut; 310 311 ut.sig[0] = 'R'; 312 ut.sig[1] = 'T'; 313 ut.sig[2] = 'L'; 314 ut.sig[3] = 'D'; 315 ut.event = event; 316 ut.handle = handle; 317 ut.mapbase = mapbase; 318 ut.mapsize = mapsize; 319 ut.refcnt = refcnt; 320 bzero(ut.name, sizeof(ut.name)); 321 if (name) 322 strlcpy(ut.name, name, sizeof(ut.name)); 323 utrace(&ut, sizeof(ut)); 324 } 325 326 /* 327 * Main entry point for dynamic linking. The first argument is the 328 * stack pointer. The stack is expected to be laid out as described 329 * in the SVR4 ABI specification, Intel 386 Processor Supplement. 330 * Specifically, the stack pointer points to a word containing 331 * ARGC. Following that in the stack is a null-terminated sequence 332 * of pointers to argument strings. Then comes a null-terminated 333 * sequence of pointers to environment strings. Finally, there is a 334 * sequence of "auxiliary vector" entries. 335 * 336 * The second argument points to a place to store the dynamic linker's 337 * exit procedure pointer and the third to a place to store the main 338 * program's object. 339 * 340 * The return value is the main program's entry point. 341 */ 342 func_ptr_type 343 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) 344 { 345 Elf_Auxinfo *aux_info[AT_COUNT]; 346 int i; 347 int argc; 348 char **argv; 349 char **env; 350 Elf_Auxinfo *aux; 351 Elf_Auxinfo *auxp; 352 const char *argv0; 353 Objlist_Entry *entry; 354 Obj_Entry *obj; 355 Obj_Entry **preload_tail; 356 Obj_Entry *last_interposer; 357 Objlist initlist; 358 RtldLockState lockstate; 359 char *library_path_rpath; 360 int mib[2]; 361 size_t len; 362 363 /* 364 * On entry, the dynamic linker itself has not been relocated yet. 365 * Be very careful not to reference any global data until after 366 * init_rtld has returned. It is OK to reference file-scope statics 367 * and string constants, and to call static and global functions. 368 */ 369 370 /* Find the auxiliary vector on the stack. */ 371 argc = *sp++; 372 argv = (char **) sp; 373 sp += argc + 1; /* Skip over arguments and NULL terminator */ 374 env = (char **) sp; 375 while (*sp++ != 0) /* Skip over environment, and NULL terminator */ 376 ; 377 aux = (Elf_Auxinfo *) sp; 378 379 /* Digest the auxiliary vector. */ 380 for (i = 0; i < AT_COUNT; i++) 381 aux_info[i] = NULL; 382 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { 383 if (auxp->a_type < AT_COUNT) 384 aux_info[auxp->a_type] = auxp; 385 } 386 387 /* Initialize and relocate ourselves. */ 388 assert(aux_info[AT_BASE] != NULL); 389 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info); 390 391 __progname = obj_rtld.path; 392 argv0 = argv[0] != NULL ? argv[0] : "(null)"; 393 environ = env; 394 main_argc = argc; 395 main_argv = argv; 396 397 if (aux_info[AT_CANARY] != NULL && 398 aux_info[AT_CANARY]->a_un.a_ptr != NULL) { 399 i = aux_info[AT_CANARYLEN]->a_un.a_val; 400 if (i > sizeof(__stack_chk_guard)) 401 i = sizeof(__stack_chk_guard); 402 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i); 403 } else { 404 mib[0] = CTL_KERN; 405 mib[1] = KERN_ARND; 406 407 len = sizeof(__stack_chk_guard); 408 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 || 409 len != sizeof(__stack_chk_guard)) { 410 /* If sysctl was unsuccessful, use the "terminator canary". */ 411 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0; 412 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0; 413 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n'; 414 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255; 415 } 416 } 417 418 trust = !issetugid(); 419 420 ld_bind_now = getenv(LD_ "BIND_NOW"); 421 /* 422 * If the process is tainted, then we un-set the dangerous environment 423 * variables. The process will be marked as tainted until setuid(2) 424 * is called. If any child process calls setuid(2) we do not want any 425 * future processes to honor the potentially un-safe variables. 426 */ 427 if (!trust) { 428 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") || 429 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") || 430 unsetenv(LD_ "LIBMAP_DISABLE") || 431 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") || 432 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) { 433 _rtld_error("environment corrupt; aborting"); 434 rtld_die(); 435 } 436 } 437 ld_debug = getenv(LD_ "DEBUG"); 438 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL; 439 libmap_override = getenv(LD_ "LIBMAP"); 440 ld_library_path = getenv(LD_ "LIBRARY_PATH"); 441 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS"); 442 ld_preload = getenv(LD_ "PRELOAD"); 443 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH"); 444 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL; 445 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH"); 446 if (library_path_rpath != NULL) { 447 if (library_path_rpath[0] == 'y' || 448 library_path_rpath[0] == 'Y' || 449 library_path_rpath[0] == '1') 450 ld_library_path_rpath = true; 451 else 452 ld_library_path_rpath = false; 453 } 454 dangerous_ld_env = libmap_disable || (libmap_override != NULL) || 455 (ld_library_path != NULL) || (ld_preload != NULL) || 456 (ld_elf_hints_path != NULL) || ld_loadfltr; 457 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS"); 458 ld_utrace = getenv(LD_ "UTRACE"); 459 460 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0) 461 ld_elf_hints_path = _PATH_ELF_HINTS; 462 463 if (ld_debug != NULL && *ld_debug != '\0') 464 debug = 1; 465 dbg("%s is initialized, base address = %p", __progname, 466 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); 467 dbg("RTLD dynamic = %p", obj_rtld.dynamic); 468 dbg("RTLD pltgot = %p", obj_rtld.pltgot); 469 470 dbg("initializing thread locks"); 471 lockdflt_init(); 472 473 /* 474 * Load the main program, or process its program header if it is 475 * already loaded. 476 */ 477 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ 478 int fd = aux_info[AT_EXECFD]->a_un.a_val; 479 dbg("loading main program"); 480 obj_main = map_object(fd, argv0, NULL); 481 close(fd); 482 if (obj_main == NULL) 483 rtld_die(); 484 max_stack_flags = obj->stack_flags; 485 } else { /* Main program already loaded. */ 486 const Elf_Phdr *phdr; 487 int phnum; 488 caddr_t entry; 489 490 dbg("processing main program's program header"); 491 assert(aux_info[AT_PHDR] != NULL); 492 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; 493 assert(aux_info[AT_PHNUM] != NULL); 494 phnum = aux_info[AT_PHNUM]->a_un.a_val; 495 assert(aux_info[AT_PHENT] != NULL); 496 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); 497 assert(aux_info[AT_ENTRY] != NULL); 498 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; 499 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) 500 rtld_die(); 501 } 502 503 if (aux_info[AT_EXECPATH] != 0) { 504 char *kexecpath; 505 char buf[MAXPATHLEN]; 506 507 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; 508 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); 509 if (kexecpath[0] == '/') 510 obj_main->path = kexecpath; 511 else if (getcwd(buf, sizeof(buf)) == NULL || 512 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || 513 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) 514 obj_main->path = xstrdup(argv0); 515 else 516 obj_main->path = xstrdup(buf); 517 } else { 518 dbg("No AT_EXECPATH"); 519 obj_main->path = xstrdup(argv0); 520 } 521 dbg("obj_main path %s", obj_main->path); 522 obj_main->mainprog = true; 523 524 if (aux_info[AT_STACKPROT] != NULL && 525 aux_info[AT_STACKPROT]->a_un.a_val != 0) 526 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; 527 528 #ifndef COMPAT_32BIT 529 /* 530 * Get the actual dynamic linker pathname from the executable if 531 * possible. (It should always be possible.) That ensures that 532 * gdb will find the right dynamic linker even if a non-standard 533 * one is being used. 534 */ 535 if (obj_main->interp != NULL && 536 strcmp(obj_main->interp, obj_rtld.path) != 0) { 537 free(obj_rtld.path); 538 obj_rtld.path = xstrdup(obj_main->interp); 539 __progname = obj_rtld.path; 540 } 541 #endif 542 543 digest_dynamic(obj_main, 0); 544 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", 545 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, 546 obj_main->dynsymcount); 547 548 linkmap_add(obj_main); 549 linkmap_add(&obj_rtld); 550 551 /* Link the main program into the list of objects. */ 552 *obj_tail = obj_main; 553 obj_tail = &obj_main->next; 554 obj_count++; 555 obj_loads++; 556 557 /* Initialize a fake symbol for resolving undefined weak references. */ 558 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); 559 sym_zero.st_shndx = SHN_UNDEF; 560 sym_zero.st_value = -(uintptr_t)obj_main->relocbase; 561 562 if (!libmap_disable) 563 libmap_disable = (bool)lm_init(libmap_override); 564 565 dbg("loading LD_PRELOAD libraries"); 566 if (load_preload_objects() == -1) 567 rtld_die(); 568 preload_tail = obj_tail; 569 570 dbg("loading needed objects"); 571 if (load_needed_objects(obj_main, 0) == -1) 572 rtld_die(); 573 574 /* Make a list of all objects loaded at startup. */ 575 last_interposer = obj_main; 576 for (obj = obj_list; obj != NULL; obj = obj->next) { 577 if (obj->z_interpose && obj != obj_main) { 578 objlist_put_after(&list_main, last_interposer, obj); 579 last_interposer = obj; 580 } else { 581 objlist_push_tail(&list_main, obj); 582 } 583 obj->refcount++; 584 } 585 586 dbg("checking for required versions"); 587 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) 588 rtld_die(); 589 590 if (ld_tracing) { /* We're done */ 591 trace_loaded_objects(obj_main); 592 exit(0); 593 } 594 595 if (getenv(LD_ "DUMP_REL_PRE") != NULL) { 596 dump_relocations(obj_main); 597 exit (0); 598 } 599 600 /* 601 * Processing tls relocations requires having the tls offsets 602 * initialized. Prepare offsets before starting initial 603 * relocation processing. 604 */ 605 dbg("initializing initial thread local storage offsets"); 606 STAILQ_FOREACH(entry, &list_main, link) { 607 /* 608 * Allocate all the initial objects out of the static TLS 609 * block even if they didn't ask for it. 610 */ 611 allocate_tls_offset(entry->obj); 612 } 613 614 if (relocate_objects(obj_main, 615 ld_bind_now != NULL && *ld_bind_now != '\0', 616 &obj_rtld, SYMLOOK_EARLY, NULL) == -1) 617 rtld_die(); 618 619 dbg("doing copy relocations"); 620 if (do_copy_relocations(obj_main) == -1) 621 rtld_die(); 622 623 if (getenv(LD_ "DUMP_REL_POST") != NULL) { 624 dump_relocations(obj_main); 625 exit (0); 626 } 627 628 /* 629 * Setup TLS for main thread. This must be done after the 630 * relocations are processed, since tls initialization section 631 * might be the subject for relocations. 632 */ 633 dbg("initializing initial thread local storage"); 634 allocate_initial_tls(obj_list); 635 636 dbg("initializing key program variables"); 637 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); 638 set_program_var("environ", env); 639 set_program_var("__elf_aux_vector", aux); 640 641 /* Make a list of init functions to call. */ 642 objlist_init(&initlist); 643 initlist_add_objects(obj_list, preload_tail, &initlist); 644 645 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ 646 647 map_stacks_exec(NULL); 648 649 dbg("resolving ifuncs"); 650 if (resolve_objects_ifunc(obj_main, 651 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, 652 NULL) == -1) 653 rtld_die(); 654 655 if (!obj_main->crt_no_init) { 656 /* 657 * Make sure we don't call the main program's init and fini 658 * functions for binaries linked with old crt1 which calls 659 * _init itself. 660 */ 661 obj_main->init = obj_main->fini = (Elf_Addr)NULL; 662 obj_main->preinit_array = obj_main->init_array = 663 obj_main->fini_array = (Elf_Addr)NULL; 664 } 665 666 wlock_acquire(rtld_bind_lock, &lockstate); 667 if (obj_main->crt_no_init) 668 preinit_main(); 669 objlist_call_init(&initlist, &lockstate); 670 _r_debug_postinit(&obj_main->linkmap); 671 objlist_clear(&initlist); 672 dbg("loading filtees"); 673 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 674 if (ld_loadfltr || obj->z_loadfltr) 675 load_filtees(obj, 0, &lockstate); 676 } 677 lock_release(rtld_bind_lock, &lockstate); 678 679 dbg("transferring control to program entry point = %p", obj_main->entry); 680 681 /* Return the exit procedure and the program entry point. */ 682 *exit_proc = rtld_exit; 683 *objp = obj_main; 684 return (func_ptr_type) obj_main->entry; 685 } 686 687 void * 688 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) 689 { 690 void *ptr; 691 Elf_Addr target; 692 693 ptr = (void *)make_function_pointer(def, obj); 694 target = ((Elf_Addr (*)(void))ptr)(); 695 return ((void *)target); 696 } 697 698 Elf_Addr 699 _rtld_bind(Obj_Entry *obj, Elf_Size reloff) 700 { 701 const Elf_Rel *rel; 702 const Elf_Sym *def; 703 const Obj_Entry *defobj; 704 Elf_Addr *where; 705 Elf_Addr target; 706 RtldLockState lockstate; 707 708 rlock_acquire(rtld_bind_lock, &lockstate); 709 if (sigsetjmp(lockstate.env, 0) != 0) 710 lock_upgrade(rtld_bind_lock, &lockstate); 711 if (obj->pltrel) 712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); 713 else 714 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); 715 716 where = (Elf_Addr *) (obj->relocbase + rel->r_offset); 717 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL, 718 &lockstate); 719 if (def == NULL) 720 rtld_die(); 721 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 722 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 723 else 724 target = (Elf_Addr)(defobj->relocbase + def->st_value); 725 726 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", 727 defobj->strtab + def->st_name, basename(obj->path), 728 (void *)target, basename(defobj->path)); 729 730 /* 731 * Write the new contents for the jmpslot. Note that depending on 732 * architecture, the value which we need to return back to the 733 * lazy binding trampoline may or may not be the target 734 * address. The value returned from reloc_jmpslot() is the value 735 * that the trampoline needs. 736 */ 737 target = reloc_jmpslot(where, target, defobj, obj, rel); 738 lock_release(rtld_bind_lock, &lockstate); 739 return target; 740 } 741 742 /* 743 * Error reporting function. Use it like printf. If formats the message 744 * into a buffer, and sets things up so that the next call to dlerror() 745 * will return the message. 746 */ 747 void 748 _rtld_error(const char *fmt, ...) 749 { 750 static char buf[512]; 751 va_list ap; 752 753 va_start(ap, fmt); 754 rtld_vsnprintf(buf, sizeof buf, fmt, ap); 755 error_message = buf; 756 va_end(ap); 757 } 758 759 /* 760 * Return a dynamically-allocated copy of the current error message, if any. 761 */ 762 static char * 763 errmsg_save(void) 764 { 765 return error_message == NULL ? NULL : xstrdup(error_message); 766 } 767 768 /* 769 * Restore the current error message from a copy which was previously saved 770 * by errmsg_save(). The copy is freed. 771 */ 772 static void 773 errmsg_restore(char *saved_msg) 774 { 775 if (saved_msg == NULL) 776 error_message = NULL; 777 else { 778 _rtld_error("%s", saved_msg); 779 free(saved_msg); 780 } 781 } 782 783 static const char * 784 basename(const char *name) 785 { 786 const char *p = strrchr(name, '/'); 787 return p != NULL ? p + 1 : name; 788 } 789 790 static struct utsname uts; 791 792 static char * 793 origin_subst_one(Obj_Entry *obj, char *real, const char *kw, 794 const char *subst, bool may_free) 795 { 796 char *p, *p1, *res, *resp; 797 int subst_len, kw_len, subst_count, old_len, new_len; 798 799 kw_len = strlen(kw); 800 801 /* 802 * First, count the number of the keyword occurences, to 803 * preallocate the final string. 804 */ 805 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { 806 p1 = strstr(p, kw); 807 if (p1 == NULL) 808 break; 809 } 810 811 /* 812 * If the keyword is not found, just return. 813 * 814 * Return non-substituted string if resolution failed. We 815 * cannot do anything more reasonable, the failure mode of the 816 * caller is unresolved library anyway. 817 */ 818 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) 819 return (may_free ? real : xstrdup(real)); 820 if (obj != NULL) 821 subst = obj->origin_path; 822 823 /* 824 * There is indeed something to substitute. Calculate the 825 * length of the resulting string, and allocate it. 826 */ 827 subst_len = strlen(subst); 828 old_len = strlen(real); 829 new_len = old_len + (subst_len - kw_len) * subst_count; 830 res = xmalloc(new_len + 1); 831 832 /* 833 * Now, execute the substitution loop. 834 */ 835 for (p = real, resp = res, *resp = '\0';;) { 836 p1 = strstr(p, kw); 837 if (p1 != NULL) { 838 /* Copy the prefix before keyword. */ 839 memcpy(resp, p, p1 - p); 840 resp += p1 - p; 841 /* Keyword replacement. */ 842 memcpy(resp, subst, subst_len); 843 resp += subst_len; 844 *resp = '\0'; 845 p = p1 + kw_len; 846 } else 847 break; 848 } 849 850 /* Copy to the end of string and finish. */ 851 strcat(resp, p); 852 if (may_free) 853 free(real); 854 return (res); 855 } 856 857 static char * 858 origin_subst(Obj_Entry *obj, char *real) 859 { 860 char *res1, *res2, *res3, *res4; 861 862 if (obj == NULL || !trust) 863 return (xstrdup(real)); 864 if (uts.sysname[0] == '\0') { 865 if (uname(&uts) != 0) { 866 _rtld_error("utsname failed: %d", errno); 867 return (NULL); 868 } 869 } 870 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false); 871 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true); 872 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true); 873 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true); 874 return (res4); 875 } 876 877 void 878 rtld_die(void) 879 { 880 const char *msg = dlerror(); 881 882 if (msg == NULL) 883 msg = "Fatal error"; 884 rtld_fdputstr(STDERR_FILENO, msg); 885 rtld_fdputchar(STDERR_FILENO, '\n'); 886 _exit(1); 887 } 888 889 /* 890 * Process a shared object's DYNAMIC section, and save the important 891 * information in its Obj_Entry structure. 892 */ 893 static void 894 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, 895 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) 896 { 897 const Elf_Dyn *dynp; 898 Needed_Entry **needed_tail = &obj->needed; 899 Needed_Entry **needed_filtees_tail = &obj->needed_filtees; 900 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; 901 const Elf_Hashelt *hashtab; 902 const Elf32_Word *hashval; 903 Elf32_Word bkt, nmaskwords; 904 int bloom_size32; 905 int plttype = DT_REL; 906 907 *dyn_rpath = NULL; 908 *dyn_soname = NULL; 909 *dyn_runpath = NULL; 910 911 obj->bind_now = false; 912 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { 913 switch (dynp->d_tag) { 914 915 case DT_REL: 916 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); 917 break; 918 919 case DT_RELSZ: 920 obj->relsize = dynp->d_un.d_val; 921 break; 922 923 case DT_RELENT: 924 assert(dynp->d_un.d_val == sizeof(Elf_Rel)); 925 break; 926 927 case DT_JMPREL: 928 obj->pltrel = (const Elf_Rel *) 929 (obj->relocbase + dynp->d_un.d_ptr); 930 break; 931 932 case DT_PLTRELSZ: 933 obj->pltrelsize = dynp->d_un.d_val; 934 break; 935 936 case DT_RELA: 937 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); 938 break; 939 940 case DT_RELASZ: 941 obj->relasize = dynp->d_un.d_val; 942 break; 943 944 case DT_RELAENT: 945 assert(dynp->d_un.d_val == sizeof(Elf_Rela)); 946 break; 947 948 case DT_PLTREL: 949 plttype = dynp->d_un.d_val; 950 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); 951 break; 952 953 case DT_SYMTAB: 954 obj->symtab = (const Elf_Sym *) 955 (obj->relocbase + dynp->d_un.d_ptr); 956 break; 957 958 case DT_SYMENT: 959 assert(dynp->d_un.d_val == sizeof(Elf_Sym)); 960 break; 961 962 case DT_STRTAB: 963 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); 964 break; 965 966 case DT_STRSZ: 967 obj->strsize = dynp->d_un.d_val; 968 break; 969 970 case DT_VERNEED: 971 obj->verneed = (const Elf_Verneed *) (obj->relocbase + 972 dynp->d_un.d_val); 973 break; 974 975 case DT_VERNEEDNUM: 976 obj->verneednum = dynp->d_un.d_val; 977 break; 978 979 case DT_VERDEF: 980 obj->verdef = (const Elf_Verdef *) (obj->relocbase + 981 dynp->d_un.d_val); 982 break; 983 984 case DT_VERDEFNUM: 985 obj->verdefnum = dynp->d_un.d_val; 986 break; 987 988 case DT_VERSYM: 989 obj->versyms = (const Elf_Versym *)(obj->relocbase + 990 dynp->d_un.d_val); 991 break; 992 993 case DT_HASH: 994 { 995 hashtab = (const Elf_Hashelt *)(obj->relocbase + 996 dynp->d_un.d_ptr); 997 obj->nbuckets = hashtab[0]; 998 obj->nchains = hashtab[1]; 999 obj->buckets = hashtab + 2; 1000 obj->chains = obj->buckets + obj->nbuckets; 1001 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && 1002 obj->buckets != NULL; 1003 } 1004 break; 1005 1006 case DT_GNU_HASH: 1007 { 1008 hashtab = (const Elf_Hashelt *)(obj->relocbase + 1009 dynp->d_un.d_ptr); 1010 obj->nbuckets_gnu = hashtab[0]; 1011 obj->symndx_gnu = hashtab[1]; 1012 nmaskwords = hashtab[2]; 1013 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; 1014 obj->maskwords_bm_gnu = nmaskwords - 1; 1015 obj->shift2_gnu = hashtab[3]; 1016 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4); 1017 obj->buckets_gnu = hashtab + 4 + bloom_size32; 1018 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - 1019 obj->symndx_gnu; 1020 /* Number of bitmask words is required to be power of 2 */ 1021 obj->valid_hash_gnu = powerof2(nmaskwords) && 1022 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; 1023 } 1024 break; 1025 1026 case DT_NEEDED: 1027 if (!obj->rtld) { 1028 Needed_Entry *nep = NEW(Needed_Entry); 1029 nep->name = dynp->d_un.d_val; 1030 nep->obj = NULL; 1031 nep->next = NULL; 1032 1033 *needed_tail = nep; 1034 needed_tail = &nep->next; 1035 } 1036 break; 1037 1038 case DT_FILTER: 1039 if (!obj->rtld) { 1040 Needed_Entry *nep = NEW(Needed_Entry); 1041 nep->name = dynp->d_un.d_val; 1042 nep->obj = NULL; 1043 nep->next = NULL; 1044 1045 *needed_filtees_tail = nep; 1046 needed_filtees_tail = &nep->next; 1047 } 1048 break; 1049 1050 case DT_AUXILIARY: 1051 if (!obj->rtld) { 1052 Needed_Entry *nep = NEW(Needed_Entry); 1053 nep->name = dynp->d_un.d_val; 1054 nep->obj = NULL; 1055 nep->next = NULL; 1056 1057 *needed_aux_filtees_tail = nep; 1058 needed_aux_filtees_tail = &nep->next; 1059 } 1060 break; 1061 1062 case DT_PLTGOT: 1063 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); 1064 break; 1065 1066 case DT_TEXTREL: 1067 obj->textrel = true; 1068 break; 1069 1070 case DT_SYMBOLIC: 1071 obj->symbolic = true; 1072 break; 1073 1074 case DT_RPATH: 1075 /* 1076 * We have to wait until later to process this, because we 1077 * might not have gotten the address of the string table yet. 1078 */ 1079 *dyn_rpath = dynp; 1080 break; 1081 1082 case DT_SONAME: 1083 *dyn_soname = dynp; 1084 break; 1085 1086 case DT_RUNPATH: 1087 *dyn_runpath = dynp; 1088 break; 1089 1090 case DT_INIT: 1091 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1092 break; 1093 1094 case DT_PREINIT_ARRAY: 1095 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1096 break; 1097 1098 case DT_PREINIT_ARRAYSZ: 1099 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1100 break; 1101 1102 case DT_INIT_ARRAY: 1103 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1104 break; 1105 1106 case DT_INIT_ARRAYSZ: 1107 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1108 break; 1109 1110 case DT_FINI: 1111 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr); 1112 break; 1113 1114 case DT_FINI_ARRAY: 1115 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr); 1116 break; 1117 1118 case DT_FINI_ARRAYSZ: 1119 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr); 1120 break; 1121 1122 /* 1123 * Don't process DT_DEBUG on MIPS as the dynamic section 1124 * is mapped read-only. DT_MIPS_RLD_MAP is used instead. 1125 */ 1126 1127 #ifndef __mips__ 1128 case DT_DEBUG: 1129 /* XXX - not implemented yet */ 1130 if (!early) 1131 dbg("Filling in DT_DEBUG entry"); 1132 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; 1133 break; 1134 #endif 1135 1136 case DT_FLAGS: 1137 if (dynp->d_un.d_val & DF_ORIGIN) 1138 obj->z_origin = true; 1139 if (dynp->d_un.d_val & DF_SYMBOLIC) 1140 obj->symbolic = true; 1141 if (dynp->d_un.d_val & DF_TEXTREL) 1142 obj->textrel = true; 1143 if (dynp->d_un.d_val & DF_BIND_NOW) 1144 obj->bind_now = true; 1145 /*if (dynp->d_un.d_val & DF_STATIC_TLS) 1146 ;*/ 1147 break; 1148 #ifdef __mips__ 1149 case DT_MIPS_LOCAL_GOTNO: 1150 obj->local_gotno = dynp->d_un.d_val; 1151 break; 1152 1153 case DT_MIPS_SYMTABNO: 1154 obj->symtabno = dynp->d_un.d_val; 1155 break; 1156 1157 case DT_MIPS_GOTSYM: 1158 obj->gotsym = dynp->d_un.d_val; 1159 break; 1160 1161 case DT_MIPS_RLD_MAP: 1162 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug; 1163 break; 1164 #endif 1165 1166 case DT_FLAGS_1: 1167 if (dynp->d_un.d_val & DF_1_NOOPEN) 1168 obj->z_noopen = true; 1169 if (dynp->d_un.d_val & DF_1_ORIGIN) 1170 obj->z_origin = true; 1171 if (dynp->d_un.d_val & DF_1_GLOBAL) 1172 obj->z_global = true; 1173 if (dynp->d_un.d_val & DF_1_BIND_NOW) 1174 obj->bind_now = true; 1175 if (dynp->d_un.d_val & DF_1_NODELETE) 1176 obj->z_nodelete = true; 1177 if (dynp->d_un.d_val & DF_1_LOADFLTR) 1178 obj->z_loadfltr = true; 1179 if (dynp->d_un.d_val & DF_1_INTERPOSE) 1180 obj->z_interpose = true; 1181 if (dynp->d_un.d_val & DF_1_NODEFLIB) 1182 obj->z_nodeflib = true; 1183 break; 1184 1185 default: 1186 if (!early) { 1187 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, 1188 (long)dynp->d_tag); 1189 } 1190 break; 1191 } 1192 } 1193 1194 obj->traced = false; 1195 1196 if (plttype == DT_RELA) { 1197 obj->pltrela = (const Elf_Rela *) obj->pltrel; 1198 obj->pltrel = NULL; 1199 obj->pltrelasize = obj->pltrelsize; 1200 obj->pltrelsize = 0; 1201 } 1202 1203 /* Determine size of dynsym table (equal to nchains of sysv hash) */ 1204 if (obj->valid_hash_sysv) 1205 obj->dynsymcount = obj->nchains; 1206 else if (obj->valid_hash_gnu) { 1207 obj->dynsymcount = 0; 1208 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { 1209 if (obj->buckets_gnu[bkt] == 0) 1210 continue; 1211 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; 1212 do 1213 obj->dynsymcount++; 1214 while ((*hashval++ & 1u) == 0); 1215 } 1216 obj->dynsymcount += obj->symndx_gnu; 1217 } 1218 } 1219 1220 static bool 1221 obj_resolve_origin(Obj_Entry *obj) 1222 { 1223 1224 if (obj->origin_path != NULL) 1225 return (true); 1226 obj->origin_path = xmalloc(PATH_MAX); 1227 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); 1228 } 1229 1230 static void 1231 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, 1232 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) 1233 { 1234 1235 if (obj->z_origin && !obj_resolve_origin(obj)) 1236 rtld_die(); 1237 1238 if (dyn_runpath != NULL) { 1239 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val; 1240 obj->runpath = origin_subst(obj, obj->runpath); 1241 } else if (dyn_rpath != NULL) { 1242 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val; 1243 obj->rpath = origin_subst(obj, obj->rpath); 1244 } 1245 if (dyn_soname != NULL) 1246 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); 1247 } 1248 1249 static void 1250 digest_dynamic(Obj_Entry *obj, int early) 1251 { 1252 const Elf_Dyn *dyn_rpath; 1253 const Elf_Dyn *dyn_soname; 1254 const Elf_Dyn *dyn_runpath; 1255 1256 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); 1257 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath); 1258 } 1259 1260 /* 1261 * Process a shared object's program header. This is used only for the 1262 * main program, when the kernel has already loaded the main program 1263 * into memory before calling the dynamic linker. It creates and 1264 * returns an Obj_Entry structure. 1265 */ 1266 static Obj_Entry * 1267 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) 1268 { 1269 Obj_Entry *obj; 1270 const Elf_Phdr *phlimit = phdr + phnum; 1271 const Elf_Phdr *ph; 1272 Elf_Addr note_start, note_end; 1273 int nsegs = 0; 1274 1275 obj = obj_new(); 1276 for (ph = phdr; ph < phlimit; ph++) { 1277 if (ph->p_type != PT_PHDR) 1278 continue; 1279 1280 obj->phdr = phdr; 1281 obj->phsize = ph->p_memsz; 1282 obj->relocbase = (caddr_t)phdr - ph->p_vaddr; 1283 break; 1284 } 1285 1286 obj->stack_flags = PF_X | PF_R | PF_W; 1287 1288 for (ph = phdr; ph < phlimit; ph++) { 1289 switch (ph->p_type) { 1290 1291 case PT_INTERP: 1292 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); 1293 break; 1294 1295 case PT_LOAD: 1296 if (nsegs == 0) { /* First load segment */ 1297 obj->vaddrbase = trunc_page(ph->p_vaddr); 1298 obj->mapbase = obj->vaddrbase + obj->relocbase; 1299 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - 1300 obj->vaddrbase; 1301 } else { /* Last load segment */ 1302 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - 1303 obj->vaddrbase; 1304 } 1305 nsegs++; 1306 break; 1307 1308 case PT_DYNAMIC: 1309 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); 1310 break; 1311 1312 case PT_TLS: 1313 obj->tlsindex = 1; 1314 obj->tlssize = ph->p_memsz; 1315 obj->tlsalign = ph->p_align; 1316 obj->tlsinitsize = ph->p_filesz; 1317 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase); 1318 break; 1319 1320 case PT_GNU_STACK: 1321 obj->stack_flags = ph->p_flags; 1322 break; 1323 1324 case PT_GNU_RELRO: 1325 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); 1326 obj->relro_size = round_page(ph->p_memsz); 1327 break; 1328 1329 case PT_NOTE: 1330 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; 1331 note_end = note_start + ph->p_filesz; 1332 digest_notes(obj, note_start, note_end); 1333 break; 1334 } 1335 } 1336 if (nsegs < 1) { 1337 _rtld_error("%s: too few PT_LOAD segments", path); 1338 return NULL; 1339 } 1340 1341 obj->entry = entry; 1342 return obj; 1343 } 1344 1345 void 1346 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) 1347 { 1348 const Elf_Note *note; 1349 const char *note_name; 1350 uintptr_t p; 1351 1352 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; 1353 note = (const Elf_Note *)((const char *)(note + 1) + 1354 roundup2(note->n_namesz, sizeof(Elf32_Addr)) + 1355 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { 1356 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || 1357 note->n_descsz != sizeof(int32_t)) 1358 continue; 1359 if (note->n_type != ABI_NOTETYPE && 1360 note->n_type != CRT_NOINIT_NOTETYPE) 1361 continue; 1362 note_name = (const char *)(note + 1); 1363 if (strncmp(NOTE_FREEBSD_VENDOR, note_name, 1364 sizeof(NOTE_FREEBSD_VENDOR)) != 0) 1365 continue; 1366 switch (note->n_type) { 1367 case ABI_NOTETYPE: 1368 /* FreeBSD osrel note */ 1369 p = (uintptr_t)(note + 1); 1370 p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); 1371 obj->osrel = *(const int32_t *)(p); 1372 dbg("note osrel %d", obj->osrel); 1373 break; 1374 case CRT_NOINIT_NOTETYPE: 1375 /* FreeBSD 'crt does not call init' note */ 1376 obj->crt_no_init = true; 1377 dbg("note crt_no_init"); 1378 break; 1379 } 1380 } 1381 } 1382 1383 static Obj_Entry * 1384 dlcheck(void *handle) 1385 { 1386 Obj_Entry *obj; 1387 1388 for (obj = obj_list; obj != NULL; obj = obj->next) 1389 if (obj == (Obj_Entry *) handle) 1390 break; 1391 1392 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { 1393 _rtld_error("Invalid shared object handle %p", handle); 1394 return NULL; 1395 } 1396 return obj; 1397 } 1398 1399 /* 1400 * If the given object is already in the donelist, return true. Otherwise 1401 * add the object to the list and return false. 1402 */ 1403 static bool 1404 donelist_check(DoneList *dlp, const Obj_Entry *obj) 1405 { 1406 unsigned int i; 1407 1408 for (i = 0; i < dlp->num_used; i++) 1409 if (dlp->objs[i] == obj) 1410 return true; 1411 /* 1412 * Our donelist allocation should always be sufficient. But if 1413 * our threads locking isn't working properly, more shared objects 1414 * could have been loaded since we allocated the list. That should 1415 * never happen, but we'll handle it properly just in case it does. 1416 */ 1417 if (dlp->num_used < dlp->num_alloc) 1418 dlp->objs[dlp->num_used++] = obj; 1419 return false; 1420 } 1421 1422 /* 1423 * Hash function for symbol table lookup. Don't even think about changing 1424 * this. It is specified by the System V ABI. 1425 */ 1426 unsigned long 1427 elf_hash(const char *name) 1428 { 1429 const unsigned char *p = (const unsigned char *) name; 1430 unsigned long h = 0; 1431 unsigned long g; 1432 1433 while (*p != '\0') { 1434 h = (h << 4) + *p++; 1435 if ((g = h & 0xf0000000) != 0) 1436 h ^= g >> 24; 1437 h &= ~g; 1438 } 1439 return h; 1440 } 1441 1442 /* 1443 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits 1444 * unsigned in case it's implemented with a wider type. 1445 */ 1446 static uint32_t 1447 gnu_hash(const char *s) 1448 { 1449 uint32_t h; 1450 unsigned char c; 1451 1452 h = 5381; 1453 for (c = *s; c != '\0'; c = *++s) 1454 h = h * 33 + c; 1455 return (h & 0xffffffff); 1456 } 1457 1458 1459 /* 1460 * Find the library with the given name, and return its full pathname. 1461 * The returned string is dynamically allocated. Generates an error 1462 * message and returns NULL if the library cannot be found. 1463 * 1464 * If the second argument is non-NULL, then it refers to an already- 1465 * loaded shared object, whose library search path will be searched. 1466 * 1467 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its 1468 * descriptor (which is close-on-exec) will be passed out via the third 1469 * argument. 1470 * 1471 * The search order is: 1472 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) 1473 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) 1474 * LD_LIBRARY_PATH 1475 * DT_RUNPATH in the referencing file 1476 * ldconfig hints (if -z nodefaultlib, filter out default library directories 1477 * from list) 1478 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib 1479 * 1480 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. 1481 */ 1482 static char * 1483 find_library(const char *xname, const Obj_Entry *refobj, int *fdp) 1484 { 1485 char *pathname; 1486 char *name; 1487 bool nodeflib, objgiven; 1488 1489 objgiven = refobj != NULL; 1490 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */ 1491 if (xname[0] != '/' && !trust) { 1492 _rtld_error("Absolute pathname required for shared object \"%s\"", 1493 xname); 1494 return NULL; 1495 } 1496 return (origin_subst(__DECONST(Obj_Entry *, refobj), 1497 __DECONST(char *, xname))); 1498 } 1499 1500 if (libmap_disable || !objgiven || 1501 (name = lm_find(refobj->path, xname)) == NULL) 1502 name = (char *)xname; 1503 1504 dbg(" Searching for \"%s\"", name); 1505 1506 /* 1507 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall 1508 * back to pre-conforming behaviour if user requested so with 1509 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z 1510 * nodeflib. 1511 */ 1512 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { 1513 if ((pathname = search_library_path(name, ld_library_path)) != NULL || 1514 (refobj != NULL && 1515 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1516 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1517 (pathname = search_library_path(name, gethints(false))) != NULL || 1518 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) 1519 return (pathname); 1520 } else { 1521 nodeflib = objgiven ? refobj->z_nodeflib : false; 1522 if ((objgiven && 1523 (pathname = search_library_path(name, refobj->rpath)) != NULL) || 1524 (objgiven && refobj->runpath == NULL && refobj != obj_main && 1525 (pathname = search_library_path(name, obj_main->rpath)) != NULL) || 1526 (pathname = search_library_path(name, ld_library_path)) != NULL || 1527 (objgiven && 1528 (pathname = search_library_path(name, refobj->runpath)) != NULL) || 1529 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL || 1530 (pathname = search_library_path(name, gethints(nodeflib))) != NULL || 1531 (objgiven && !nodeflib && 1532 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)) 1533 return (pathname); 1534 } 1535 1536 if (objgiven && refobj->path != NULL) { 1537 _rtld_error("Shared object \"%s\" not found, required by \"%s\"", 1538 name, basename(refobj->path)); 1539 } else { 1540 _rtld_error("Shared object \"%s\" not found", name); 1541 } 1542 return NULL; 1543 } 1544 1545 /* 1546 * Given a symbol number in a referencing object, find the corresponding 1547 * definition of the symbol. Returns a pointer to the symbol, or NULL if 1548 * no definition was found. Returns a pointer to the Obj_Entry of the 1549 * defining object via the reference parameter DEFOBJ_OUT. 1550 */ 1551 const Elf_Sym * 1552 find_symdef(unsigned long symnum, const Obj_Entry *refobj, 1553 const Obj_Entry **defobj_out, int flags, SymCache *cache, 1554 RtldLockState *lockstate) 1555 { 1556 const Elf_Sym *ref; 1557 const Elf_Sym *def; 1558 const Obj_Entry *defobj; 1559 SymLook req; 1560 const char *name; 1561 int res; 1562 1563 /* 1564 * If we have already found this symbol, get the information from 1565 * the cache. 1566 */ 1567 if (symnum >= refobj->dynsymcount) 1568 return NULL; /* Bad object */ 1569 if (cache != NULL && cache[symnum].sym != NULL) { 1570 *defobj_out = cache[symnum].obj; 1571 return cache[symnum].sym; 1572 } 1573 1574 ref = refobj->symtab + symnum; 1575 name = refobj->strtab + ref->st_name; 1576 def = NULL; 1577 defobj = NULL; 1578 1579 /* 1580 * We don't have to do a full scale lookup if the symbol is local. 1581 * We know it will bind to the instance in this load module; to 1582 * which we already have a pointer (ie ref). By not doing a lookup, 1583 * we not only improve performance, but it also avoids unresolvable 1584 * symbols when local symbols are not in the hash table. This has 1585 * been seen with the ia64 toolchain. 1586 */ 1587 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { 1588 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { 1589 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, 1590 symnum); 1591 } 1592 symlook_init(&req, name); 1593 req.flags = flags; 1594 req.ventry = fetch_ventry(refobj, symnum); 1595 req.lockstate = lockstate; 1596 res = symlook_default(&req, refobj); 1597 if (res == 0) { 1598 def = req.sym_out; 1599 defobj = req.defobj_out; 1600 } 1601 } else { 1602 def = ref; 1603 defobj = refobj; 1604 } 1605 1606 /* 1607 * If we found no definition and the reference is weak, treat the 1608 * symbol as having the value zero. 1609 */ 1610 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { 1611 def = &sym_zero; 1612 defobj = obj_main; 1613 } 1614 1615 if (def != NULL) { 1616 *defobj_out = defobj; 1617 /* Record the information in the cache to avoid subsequent lookups. */ 1618 if (cache != NULL) { 1619 cache[symnum].sym = def; 1620 cache[symnum].obj = defobj; 1621 } 1622 } else { 1623 if (refobj != &obj_rtld) 1624 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); 1625 } 1626 return def; 1627 } 1628 1629 /* 1630 * Return the search path from the ldconfig hints file, reading it if 1631 * necessary. If nostdlib is true, then the default search paths are 1632 * not added to result. 1633 * 1634 * Returns NULL if there are problems with the hints file, 1635 * or if the search path there is empty. 1636 */ 1637 static const char * 1638 gethints(bool nostdlib) 1639 { 1640 static char *hints, *filtered_path; 1641 struct elfhints_hdr hdr; 1642 struct fill_search_info_args sargs, hargs; 1643 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; 1644 struct dl_serpath *SLPpath, *hintpath; 1645 char *p; 1646 unsigned int SLPndx, hintndx, fndx, fcount; 1647 int fd; 1648 size_t flen; 1649 bool skip; 1650 1651 /* First call, read the hints file */ 1652 if (hints == NULL) { 1653 /* Keep from trying again in case the hints file is bad. */ 1654 hints = ""; 1655 1656 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) 1657 return (NULL); 1658 if (read(fd, &hdr, sizeof hdr) != sizeof hdr || 1659 hdr.magic != ELFHINTS_MAGIC || 1660 hdr.version != 1) { 1661 close(fd); 1662 return (NULL); 1663 } 1664 p = xmalloc(hdr.dirlistlen + 1); 1665 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || 1666 read(fd, p, hdr.dirlistlen + 1) != 1667 (ssize_t)hdr.dirlistlen + 1) { 1668 free(p); 1669 close(fd); 1670 return (NULL); 1671 } 1672 hints = p; 1673 close(fd); 1674 } 1675 1676 /* 1677 * If caller agreed to receive list which includes the default 1678 * paths, we are done. Otherwise, if we still did not 1679 * calculated filtered result, do it now. 1680 */ 1681 if (!nostdlib) 1682 return (hints[0] != '\0' ? hints : NULL); 1683 if (filtered_path != NULL) 1684 goto filt_ret; 1685 1686 /* 1687 * Obtain the list of all configured search paths, and the 1688 * list of the default paths. 1689 * 1690 * First estimate the size of the results. 1691 */ 1692 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1693 smeta.dls_cnt = 0; 1694 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 1695 hmeta.dls_cnt = 0; 1696 1697 sargs.request = RTLD_DI_SERINFOSIZE; 1698 sargs.serinfo = &smeta; 1699 hargs.request = RTLD_DI_SERINFOSIZE; 1700 hargs.serinfo = &hmeta; 1701 1702 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1703 path_enumerate(p, fill_search_info, &hargs); 1704 1705 SLPinfo = xmalloc(smeta.dls_size); 1706 hintinfo = xmalloc(hmeta.dls_size); 1707 1708 /* 1709 * Next fetch both sets of paths. 1710 */ 1711 sargs.request = RTLD_DI_SERINFO; 1712 sargs.serinfo = SLPinfo; 1713 sargs.serpath = &SLPinfo->dls_serpath[0]; 1714 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; 1715 1716 hargs.request = RTLD_DI_SERINFO; 1717 hargs.serinfo = hintinfo; 1718 hargs.serpath = &hintinfo->dls_serpath[0]; 1719 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; 1720 1721 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs); 1722 path_enumerate(p, fill_search_info, &hargs); 1723 1724 /* 1725 * Now calculate the difference between two sets, by excluding 1726 * standard paths from the full set. 1727 */ 1728 fndx = 0; 1729 fcount = 0; 1730 filtered_path = xmalloc(hdr.dirlistlen + 1); 1731 hintpath = &hintinfo->dls_serpath[0]; 1732 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { 1733 skip = false; 1734 SLPpath = &SLPinfo->dls_serpath[0]; 1735 /* 1736 * Check each standard path against current. 1737 */ 1738 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { 1739 /* matched, skip the path */ 1740 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { 1741 skip = true; 1742 break; 1743 } 1744 } 1745 if (skip) 1746 continue; 1747 /* 1748 * Not matched against any standard path, add the path 1749 * to result. Separate consequtive paths with ':'. 1750 */ 1751 if (fcount > 0) { 1752 filtered_path[fndx] = ':'; 1753 fndx++; 1754 } 1755 fcount++; 1756 flen = strlen(hintpath->dls_name); 1757 strncpy((filtered_path + fndx), hintpath->dls_name, flen); 1758 fndx += flen; 1759 } 1760 filtered_path[fndx] = '\0'; 1761 1762 free(SLPinfo); 1763 free(hintinfo); 1764 1765 filt_ret: 1766 return (filtered_path[0] != '\0' ? filtered_path : NULL); 1767 } 1768 1769 static void 1770 init_dag(Obj_Entry *root) 1771 { 1772 const Needed_Entry *needed; 1773 const Objlist_Entry *elm; 1774 DoneList donelist; 1775 1776 if (root->dag_inited) 1777 return; 1778 donelist_init(&donelist); 1779 1780 /* Root object belongs to own DAG. */ 1781 objlist_push_tail(&root->dldags, root); 1782 objlist_push_tail(&root->dagmembers, root); 1783 donelist_check(&donelist, root); 1784 1785 /* 1786 * Add dependencies of root object to DAG in breadth order 1787 * by exploiting the fact that each new object get added 1788 * to the tail of the dagmembers list. 1789 */ 1790 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1791 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { 1792 if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) 1793 continue; 1794 objlist_push_tail(&needed->obj->dldags, root); 1795 objlist_push_tail(&root->dagmembers, needed->obj); 1796 } 1797 } 1798 root->dag_inited = true; 1799 } 1800 1801 static void 1802 process_z(Obj_Entry *root) 1803 { 1804 const Objlist_Entry *elm; 1805 Obj_Entry *obj; 1806 1807 /* 1808 * Walk over object DAG and process every dependent object 1809 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need 1810 * to grow their own DAG. 1811 * 1812 * For DF_1_GLOBAL, DAG is required for symbol lookups in 1813 * symlook_global() to work. 1814 * 1815 * For DF_1_NODELETE, the DAG should have its reference upped. 1816 */ 1817 STAILQ_FOREACH(elm, &root->dagmembers, link) { 1818 obj = elm->obj; 1819 if (obj == NULL) 1820 continue; 1821 if (obj->z_nodelete && !obj->ref_nodel) { 1822 dbg("obj %s -z nodelete", obj->path); 1823 init_dag(obj); 1824 ref_dag(obj); 1825 obj->ref_nodel = true; 1826 } 1827 if (obj->z_global && objlist_find(&list_global, obj) == NULL) { 1828 dbg("obj %s -z global", obj->path); 1829 objlist_push_tail(&list_global, obj); 1830 init_dag(obj); 1831 } 1832 } 1833 } 1834 /* 1835 * Initialize the dynamic linker. The argument is the address at which 1836 * the dynamic linker has been mapped into memory. The primary task of 1837 * this function is to relocate the dynamic linker. 1838 */ 1839 static void 1840 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) 1841 { 1842 Obj_Entry objtmp; /* Temporary rtld object */ 1843 const Elf_Dyn *dyn_rpath; 1844 const Elf_Dyn *dyn_soname; 1845 const Elf_Dyn *dyn_runpath; 1846 1847 #ifdef RTLD_INIT_PAGESIZES_EARLY 1848 /* The page size is required by the dynamic memory allocator. */ 1849 init_pagesizes(aux_info); 1850 #endif 1851 1852 /* 1853 * Conjure up an Obj_Entry structure for the dynamic linker. 1854 * 1855 * The "path" member can't be initialized yet because string constants 1856 * cannot yet be accessed. Below we will set it correctly. 1857 */ 1858 memset(&objtmp, 0, sizeof(objtmp)); 1859 objtmp.path = NULL; 1860 objtmp.rtld = true; 1861 objtmp.mapbase = mapbase; 1862 #ifdef PIC 1863 objtmp.relocbase = mapbase; 1864 #endif 1865 if (RTLD_IS_DYNAMIC()) { 1866 objtmp.dynamic = rtld_dynamic(&objtmp); 1867 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); 1868 assert(objtmp.needed == NULL); 1869 #if !defined(__mips__) 1870 /* MIPS has a bogus DT_TEXTREL. */ 1871 assert(!objtmp.textrel); 1872 #endif 1873 1874 /* 1875 * Temporarily put the dynamic linker entry into the object list, so 1876 * that symbols can be found. 1877 */ 1878 1879 relocate_objects(&objtmp, true, &objtmp, 0, NULL); 1880 } 1881 1882 /* Initialize the object list. */ 1883 obj_tail = &obj_list; 1884 1885 /* Now that non-local variables can be accesses, copy out obj_rtld. */ 1886 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); 1887 1888 #ifndef RTLD_INIT_PAGESIZES_EARLY 1889 /* The page size is required by the dynamic memory allocator. */ 1890 init_pagesizes(aux_info); 1891 #endif 1892 1893 if (aux_info[AT_OSRELDATE] != NULL) 1894 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; 1895 1896 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); 1897 1898 /* Replace the path with a dynamically allocated copy. */ 1899 obj_rtld.path = xstrdup(PATH_RTLD); 1900 1901 r_debug.r_brk = r_debug_state; 1902 r_debug.r_state = RT_CONSISTENT; 1903 } 1904 1905 /* 1906 * Retrieve the array of supported page sizes. The kernel provides the page 1907 * sizes in increasing order. 1908 */ 1909 static void 1910 init_pagesizes(Elf_Auxinfo **aux_info) 1911 { 1912 static size_t psa[MAXPAGESIZES]; 1913 int mib[2]; 1914 size_t len, size; 1915 1916 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != 1917 NULL) { 1918 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; 1919 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; 1920 } else { 1921 len = 2; 1922 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) 1923 size = sizeof(psa); 1924 else { 1925 /* As a fallback, retrieve the base page size. */ 1926 size = sizeof(psa[0]); 1927 if (aux_info[AT_PAGESZ] != NULL) { 1928 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; 1929 goto psa_filled; 1930 } else { 1931 mib[0] = CTL_HW; 1932 mib[1] = HW_PAGESIZE; 1933 len = 2; 1934 } 1935 } 1936 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { 1937 _rtld_error("sysctl for hw.pagesize(s) failed"); 1938 rtld_die(); 1939 } 1940 psa_filled: 1941 pagesizes = psa; 1942 } 1943 npagesizes = size / sizeof(pagesizes[0]); 1944 /* Discard any invalid entries at the end of the array. */ 1945 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) 1946 npagesizes--; 1947 } 1948 1949 /* 1950 * Add the init functions from a needed object list (and its recursive 1951 * needed objects) to "list". This is not used directly; it is a helper 1952 * function for initlist_add_objects(). The write lock must be held 1953 * when this function is called. 1954 */ 1955 static void 1956 initlist_add_neededs(Needed_Entry *needed, Objlist *list) 1957 { 1958 /* Recursively process the successor needed objects. */ 1959 if (needed->next != NULL) 1960 initlist_add_neededs(needed->next, list); 1961 1962 /* Process the current needed object. */ 1963 if (needed->obj != NULL) 1964 initlist_add_objects(needed->obj, &needed->obj->next, list); 1965 } 1966 1967 /* 1968 * Scan all of the DAGs rooted in the range of objects from "obj" to 1969 * "tail" and add their init functions to "list". This recurses over 1970 * the DAGs and ensure the proper init ordering such that each object's 1971 * needed libraries are initialized before the object itself. At the 1972 * same time, this function adds the objects to the global finalization 1973 * list "list_fini" in the opposite order. The write lock must be 1974 * held when this function is called. 1975 */ 1976 static void 1977 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) 1978 { 1979 1980 if (obj->init_scanned || obj->init_done) 1981 return; 1982 obj->init_scanned = true; 1983 1984 /* Recursively process the successor objects. */ 1985 if (&obj->next != tail) 1986 initlist_add_objects(obj->next, tail, list); 1987 1988 /* Recursively process the needed objects. */ 1989 if (obj->needed != NULL) 1990 initlist_add_neededs(obj->needed, list); 1991 if (obj->needed_filtees != NULL) 1992 initlist_add_neededs(obj->needed_filtees, list); 1993 if (obj->needed_aux_filtees != NULL) 1994 initlist_add_neededs(obj->needed_aux_filtees, list); 1995 1996 /* Add the object to the init list. */ 1997 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL || 1998 obj->init_array != (Elf_Addr)NULL) 1999 objlist_push_tail(list, obj); 2000 2001 /* Add the object to the global fini list in the reverse order. */ 2002 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL) 2003 && !obj->on_fini_list) { 2004 objlist_push_head(&list_fini, obj); 2005 obj->on_fini_list = true; 2006 } 2007 } 2008 2009 #ifndef FPTR_TARGET 2010 #define FPTR_TARGET(f) ((Elf_Addr) (f)) 2011 #endif 2012 2013 static void 2014 free_needed_filtees(Needed_Entry *n) 2015 { 2016 Needed_Entry *needed, *needed1; 2017 2018 for (needed = n; needed != NULL; needed = needed->next) { 2019 if (needed->obj != NULL) { 2020 dlclose(needed->obj); 2021 needed->obj = NULL; 2022 } 2023 } 2024 for (needed = n; needed != NULL; needed = needed1) { 2025 needed1 = needed->next; 2026 free(needed); 2027 } 2028 } 2029 2030 static void 2031 unload_filtees(Obj_Entry *obj) 2032 { 2033 2034 free_needed_filtees(obj->needed_filtees); 2035 obj->needed_filtees = NULL; 2036 free_needed_filtees(obj->needed_aux_filtees); 2037 obj->needed_aux_filtees = NULL; 2038 obj->filtees_loaded = false; 2039 } 2040 2041 static void 2042 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, 2043 RtldLockState *lockstate) 2044 { 2045 2046 for (; needed != NULL; needed = needed->next) { 2047 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, 2048 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | 2049 RTLD_LOCAL, lockstate); 2050 } 2051 } 2052 2053 static void 2054 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) 2055 { 2056 2057 lock_restart_for_upgrade(lockstate); 2058 if (!obj->filtees_loaded) { 2059 load_filtee1(obj, obj->needed_filtees, flags, lockstate); 2060 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); 2061 obj->filtees_loaded = true; 2062 } 2063 } 2064 2065 static int 2066 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) 2067 { 2068 Obj_Entry *obj1; 2069 2070 for (; needed != NULL; needed = needed->next) { 2071 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, 2072 flags & ~RTLD_LO_NOLOAD); 2073 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) 2074 return (-1); 2075 } 2076 return (0); 2077 } 2078 2079 /* 2080 * Given a shared object, traverse its list of needed objects, and load 2081 * each of them. Returns 0 on success. Generates an error message and 2082 * returns -1 on failure. 2083 */ 2084 static int 2085 load_needed_objects(Obj_Entry *first, int flags) 2086 { 2087 Obj_Entry *obj; 2088 2089 for (obj = first; obj != NULL; obj = obj->next) { 2090 if (process_needed(obj, obj->needed, flags) == -1) 2091 return (-1); 2092 } 2093 return (0); 2094 } 2095 2096 static int 2097 load_preload_objects(void) 2098 { 2099 char *p = ld_preload; 2100 Obj_Entry *obj; 2101 static const char delim[] = " \t:;"; 2102 2103 if (p == NULL) 2104 return 0; 2105 2106 p += strspn(p, delim); 2107 while (*p != '\0') { 2108 size_t len = strcspn(p, delim); 2109 char savech; 2110 2111 savech = p[len]; 2112 p[len] = '\0'; 2113 obj = load_object(p, -1, NULL, 0); 2114 if (obj == NULL) 2115 return -1; /* XXX - cleanup */ 2116 obj->z_interpose = true; 2117 p[len] = savech; 2118 p += len; 2119 p += strspn(p, delim); 2120 } 2121 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); 2122 return 0; 2123 } 2124 2125 static const char * 2126 printable_path(const char *path) 2127 { 2128 2129 return (path == NULL ? "<unknown>" : path); 2130 } 2131 2132 /* 2133 * Load a shared object into memory, if it is not already loaded. The 2134 * object may be specified by name or by user-supplied file descriptor 2135 * fd_u. In the later case, the fd_u descriptor is not closed, but its 2136 * duplicate is. 2137 * 2138 * Returns a pointer to the Obj_Entry for the object. Returns NULL 2139 * on failure. 2140 */ 2141 static Obj_Entry * 2142 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) 2143 { 2144 Obj_Entry *obj; 2145 int fd; 2146 struct stat sb; 2147 char *path; 2148 2149 fd = -1; 2150 if (name != NULL) { 2151 for (obj = obj_list->next; obj != NULL; obj = obj->next) { 2152 if (object_match_name(obj, name)) 2153 return (obj); 2154 } 2155 2156 path = find_library(name, refobj, &fd); 2157 if (path == NULL) 2158 return (NULL); 2159 } else 2160 path = NULL; 2161 2162 if (fd >= 0) { 2163 /* 2164 * search_library_pathfds() opens a fresh file descriptor for the 2165 * library, so there is no need to dup(). 2166 */ 2167 } else if (fd_u == -1) { 2168 /* 2169 * If we didn't find a match by pathname, or the name is not 2170 * supplied, open the file and check again by device and inode. 2171 * This avoids false mismatches caused by multiple links or ".." 2172 * in pathnames. 2173 * 2174 * To avoid a race, we open the file and use fstat() rather than 2175 * using stat(). 2176 */ 2177 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { 2178 _rtld_error("Cannot open \"%s\"", path); 2179 free(path); 2180 return (NULL); 2181 } 2182 } else { 2183 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); 2184 if (fd == -1) { 2185 _rtld_error("Cannot dup fd"); 2186 free(path); 2187 return (NULL); 2188 } 2189 } 2190 if (fstat(fd, &sb) == -1) { 2191 _rtld_error("Cannot fstat \"%s\"", printable_path(path)); 2192 close(fd); 2193 free(path); 2194 return NULL; 2195 } 2196 for (obj = obj_list->next; obj != NULL; obj = obj->next) 2197 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) 2198 break; 2199 if (obj != NULL && name != NULL) { 2200 object_add_name(obj, name); 2201 free(path); 2202 close(fd); 2203 return obj; 2204 } 2205 if (flags & RTLD_LO_NOLOAD) { 2206 free(path); 2207 close(fd); 2208 return (NULL); 2209 } 2210 2211 /* First use of this object, so we must map it in */ 2212 obj = do_load_object(fd, name, path, &sb, flags); 2213 if (obj == NULL) 2214 free(path); 2215 close(fd); 2216 2217 return obj; 2218 } 2219 2220 static Obj_Entry * 2221 do_load_object(int fd, const char *name, char *path, struct stat *sbp, 2222 int flags) 2223 { 2224 Obj_Entry *obj; 2225 struct statfs fs; 2226 2227 /* 2228 * but first, make sure that environment variables haven't been 2229 * used to circumvent the noexec flag on a filesystem. 2230 */ 2231 if (dangerous_ld_env) { 2232 if (fstatfs(fd, &fs) != 0) { 2233 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path)); 2234 return NULL; 2235 } 2236 if (fs.f_flags & MNT_NOEXEC) { 2237 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname); 2238 return NULL; 2239 } 2240 } 2241 dbg("loading \"%s\"", printable_path(path)); 2242 obj = map_object(fd, printable_path(path), sbp); 2243 if (obj == NULL) 2244 return NULL; 2245 2246 /* 2247 * If DT_SONAME is present in the object, digest_dynamic2 already 2248 * added it to the object names. 2249 */ 2250 if (name != NULL) 2251 object_add_name(obj, name); 2252 obj->path = path; 2253 digest_dynamic(obj, 0); 2254 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, 2255 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); 2256 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == 2257 RTLD_LO_DLOPEN) { 2258 dbg("refusing to load non-loadable \"%s\"", obj->path); 2259 _rtld_error("Cannot dlopen non-loadable %s", obj->path); 2260 munmap(obj->mapbase, obj->mapsize); 2261 obj_free(obj); 2262 return (NULL); 2263 } 2264 2265 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; 2266 *obj_tail = obj; 2267 obj_tail = &obj->next; 2268 obj_count++; 2269 obj_loads++; 2270 linkmap_add(obj); /* for GDB & dlinfo() */ 2271 max_stack_flags |= obj->stack_flags; 2272 2273 dbg(" %p .. %p: %s", obj->mapbase, 2274 obj->mapbase + obj->mapsize - 1, obj->path); 2275 if (obj->textrel) 2276 dbg(" WARNING: %s has impure text", obj->path); 2277 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 2278 obj->path); 2279 2280 return obj; 2281 } 2282 2283 static Obj_Entry * 2284 obj_from_addr(const void *addr) 2285 { 2286 Obj_Entry *obj; 2287 2288 for (obj = obj_list; obj != NULL; obj = obj->next) { 2289 if (addr < (void *) obj->mapbase) 2290 continue; 2291 if (addr < (void *) (obj->mapbase + obj->mapsize)) 2292 return obj; 2293 } 2294 return NULL; 2295 } 2296 2297 static void 2298 preinit_main(void) 2299 { 2300 Elf_Addr *preinit_addr; 2301 int index; 2302 2303 preinit_addr = (Elf_Addr *)obj_main->preinit_array; 2304 if (preinit_addr == NULL) 2305 return; 2306 2307 for (index = 0; index < obj_main->preinit_array_num; index++) { 2308 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { 2309 dbg("calling preinit function for %s at %p", obj_main->path, 2310 (void *)preinit_addr[index]); 2311 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 2312 0, 0, obj_main->path); 2313 call_init_pointer(obj_main, preinit_addr[index]); 2314 } 2315 } 2316 } 2317 2318 /* 2319 * Call the finalization functions for each of the objects in "list" 2320 * belonging to the DAG of "root" and referenced once. If NULL "root" 2321 * is specified, every finalization function will be called regardless 2322 * of the reference count and the list elements won't be freed. All of 2323 * the objects are expected to have non-NULL fini functions. 2324 */ 2325 static void 2326 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) 2327 { 2328 Objlist_Entry *elm; 2329 char *saved_msg; 2330 Elf_Addr *fini_addr; 2331 int index; 2332 2333 assert(root == NULL || root->refcount == 1); 2334 2335 /* 2336 * Preserve the current error message since a fini function might 2337 * call into the dynamic linker and overwrite it. 2338 */ 2339 saved_msg = errmsg_save(); 2340 do { 2341 STAILQ_FOREACH(elm, list, link) { 2342 if (root != NULL && (elm->obj->refcount != 1 || 2343 objlist_find(&root->dagmembers, elm->obj) == NULL)) 2344 continue; 2345 /* Remove object from fini list to prevent recursive invocation. */ 2346 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2347 /* 2348 * XXX: If a dlopen() call references an object while the 2349 * fini function is in progress, we might end up trying to 2350 * unload the referenced object in dlclose() or the object 2351 * won't be unloaded although its fini function has been 2352 * called. 2353 */ 2354 lock_release(rtld_bind_lock, lockstate); 2355 2356 /* 2357 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. 2358 * When this happens, DT_FINI_ARRAY is processed first. 2359 */ 2360 fini_addr = (Elf_Addr *)elm->obj->fini_array; 2361 if (fini_addr != NULL && elm->obj->fini_array_num > 0) { 2362 for (index = elm->obj->fini_array_num - 1; index >= 0; 2363 index--) { 2364 if (fini_addr[index] != 0 && fini_addr[index] != 1) { 2365 dbg("calling fini function for %s at %p", 2366 elm->obj->path, (void *)fini_addr[index]); 2367 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, 2368 (void *)fini_addr[index], 0, 0, elm->obj->path); 2369 call_initfini_pointer(elm->obj, fini_addr[index]); 2370 } 2371 } 2372 } 2373 if (elm->obj->fini != (Elf_Addr)NULL) { 2374 dbg("calling fini function for %s at %p", elm->obj->path, 2375 (void *)elm->obj->fini); 2376 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 2377 0, 0, elm->obj->path); 2378 call_initfini_pointer(elm->obj, elm->obj->fini); 2379 } 2380 wlock_acquire(rtld_bind_lock, lockstate); 2381 /* No need to free anything if process is going down. */ 2382 if (root != NULL) 2383 free(elm); 2384 /* 2385 * We must restart the list traversal after every fini call 2386 * because a dlclose() call from the fini function or from 2387 * another thread might have modified the reference counts. 2388 */ 2389 break; 2390 } 2391 } while (elm != NULL); 2392 errmsg_restore(saved_msg); 2393 } 2394 2395 /* 2396 * Call the initialization functions for each of the objects in 2397 * "list". All of the objects are expected to have non-NULL init 2398 * functions. 2399 */ 2400 static void 2401 objlist_call_init(Objlist *list, RtldLockState *lockstate) 2402 { 2403 Objlist_Entry *elm; 2404 Obj_Entry *obj; 2405 char *saved_msg; 2406 Elf_Addr *init_addr; 2407 int index; 2408 2409 /* 2410 * Clean init_scanned flag so that objects can be rechecked and 2411 * possibly initialized earlier if any of vectors called below 2412 * cause the change by using dlopen. 2413 */ 2414 for (obj = obj_list; obj != NULL; obj = obj->next) 2415 obj->init_scanned = false; 2416 2417 /* 2418 * Preserve the current error message since an init function might 2419 * call into the dynamic linker and overwrite it. 2420 */ 2421 saved_msg = errmsg_save(); 2422 STAILQ_FOREACH(elm, list, link) { 2423 if (elm->obj->init_done) /* Initialized early. */ 2424 continue; 2425 /* 2426 * Race: other thread might try to use this object before current 2427 * one completes the initilization. Not much can be done here 2428 * without better locking. 2429 */ 2430 elm->obj->init_done = true; 2431 lock_release(rtld_bind_lock, lockstate); 2432 2433 /* 2434 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. 2435 * When this happens, DT_INIT is processed first. 2436 */ 2437 if (elm->obj->init != (Elf_Addr)NULL) { 2438 dbg("calling init function for %s at %p", elm->obj->path, 2439 (void *)elm->obj->init); 2440 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 2441 0, 0, elm->obj->path); 2442 call_initfini_pointer(elm->obj, elm->obj->init); 2443 } 2444 init_addr = (Elf_Addr *)elm->obj->init_array; 2445 if (init_addr != NULL) { 2446 for (index = 0; index < elm->obj->init_array_num; index++) { 2447 if (init_addr[index] != 0 && init_addr[index] != 1) { 2448 dbg("calling init function for %s at %p", elm->obj->path, 2449 (void *)init_addr[index]); 2450 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, 2451 (void *)init_addr[index], 0, 0, elm->obj->path); 2452 call_init_pointer(elm->obj, init_addr[index]); 2453 } 2454 } 2455 } 2456 wlock_acquire(rtld_bind_lock, lockstate); 2457 } 2458 errmsg_restore(saved_msg); 2459 } 2460 2461 static void 2462 objlist_clear(Objlist *list) 2463 { 2464 Objlist_Entry *elm; 2465 2466 while (!STAILQ_EMPTY(list)) { 2467 elm = STAILQ_FIRST(list); 2468 STAILQ_REMOVE_HEAD(list, link); 2469 free(elm); 2470 } 2471 } 2472 2473 static Objlist_Entry * 2474 objlist_find(Objlist *list, const Obj_Entry *obj) 2475 { 2476 Objlist_Entry *elm; 2477 2478 STAILQ_FOREACH(elm, list, link) 2479 if (elm->obj == obj) 2480 return elm; 2481 return NULL; 2482 } 2483 2484 static void 2485 objlist_init(Objlist *list) 2486 { 2487 STAILQ_INIT(list); 2488 } 2489 2490 static void 2491 objlist_push_head(Objlist *list, Obj_Entry *obj) 2492 { 2493 Objlist_Entry *elm; 2494 2495 elm = NEW(Objlist_Entry); 2496 elm->obj = obj; 2497 STAILQ_INSERT_HEAD(list, elm, link); 2498 } 2499 2500 static void 2501 objlist_push_tail(Objlist *list, Obj_Entry *obj) 2502 { 2503 Objlist_Entry *elm; 2504 2505 elm = NEW(Objlist_Entry); 2506 elm->obj = obj; 2507 STAILQ_INSERT_TAIL(list, elm, link); 2508 } 2509 2510 static void 2511 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) 2512 { 2513 Objlist_Entry *elm, *listelm; 2514 2515 STAILQ_FOREACH(listelm, list, link) { 2516 if (listelm->obj == listobj) 2517 break; 2518 } 2519 elm = NEW(Objlist_Entry); 2520 elm->obj = obj; 2521 if (listelm != NULL) 2522 STAILQ_INSERT_AFTER(list, listelm, elm, link); 2523 else 2524 STAILQ_INSERT_TAIL(list, elm, link); 2525 } 2526 2527 static void 2528 objlist_remove(Objlist *list, Obj_Entry *obj) 2529 { 2530 Objlist_Entry *elm; 2531 2532 if ((elm = objlist_find(list, obj)) != NULL) { 2533 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); 2534 free(elm); 2535 } 2536 } 2537 2538 /* 2539 * Relocate dag rooted in the specified object. 2540 * Returns 0 on success, or -1 on failure. 2541 */ 2542 2543 static int 2544 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, 2545 int flags, RtldLockState *lockstate) 2546 { 2547 Objlist_Entry *elm; 2548 int error; 2549 2550 error = 0; 2551 STAILQ_FOREACH(elm, &root->dagmembers, link) { 2552 error = relocate_object(elm->obj, bind_now, rtldobj, flags, 2553 lockstate); 2554 if (error == -1) 2555 break; 2556 } 2557 return (error); 2558 } 2559 2560 /* 2561 * Relocate single object. 2562 * Returns 0 on success, or -1 on failure. 2563 */ 2564 static int 2565 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, 2566 int flags, RtldLockState *lockstate) 2567 { 2568 2569 if (obj->relocated) 2570 return (0); 2571 obj->relocated = true; 2572 if (obj != rtldobj) 2573 dbg("relocating \"%s\"", obj->path); 2574 2575 if (obj->symtab == NULL || obj->strtab == NULL || 2576 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) { 2577 _rtld_error("%s: Shared object has no run-time symbol table", 2578 obj->path); 2579 return (-1); 2580 } 2581 2582 if (obj->textrel) { 2583 /* There are relocations to the write-protected text segment. */ 2584 if (mprotect(obj->mapbase, obj->textsize, 2585 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { 2586 _rtld_error("%s: Cannot write-enable text segment: %s", 2587 obj->path, rtld_strerror(errno)); 2588 return (-1); 2589 } 2590 } 2591 2592 /* Process the non-PLT non-IFUNC relocations. */ 2593 if (reloc_non_plt(obj, rtldobj, flags, lockstate)) 2594 return (-1); 2595 2596 if (obj->textrel) { /* Re-protected the text segment. */ 2597 if (mprotect(obj->mapbase, obj->textsize, 2598 PROT_READ|PROT_EXEC) == -1) { 2599 _rtld_error("%s: Cannot write-protect text segment: %s", 2600 obj->path, rtld_strerror(errno)); 2601 return (-1); 2602 } 2603 } 2604 2605 /* Set the special PLT or GOT entries. */ 2606 init_pltgot(obj); 2607 2608 /* Process the PLT relocations. */ 2609 if (reloc_plt(obj) == -1) 2610 return (-1); 2611 /* Relocate the jump slots if we are doing immediate binding. */ 2612 if (obj->bind_now || bind_now) 2613 if (reloc_jmpslots(obj, flags, lockstate) == -1) 2614 return (-1); 2615 2616 /* 2617 * Process the non-PLT IFUNC relocations. The relocations are 2618 * processed in two phases, because IFUNC resolvers may 2619 * reference other symbols, which must be readily processed 2620 * before resolvers are called. 2621 */ 2622 if (obj->non_plt_gnu_ifunc && 2623 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate)) 2624 return (-1); 2625 2626 if (obj->relro_size > 0) { 2627 if (mprotect(obj->relro_page, obj->relro_size, 2628 PROT_READ) == -1) { 2629 _rtld_error("%s: Cannot enforce relro protection: %s", 2630 obj->path, rtld_strerror(errno)); 2631 return (-1); 2632 } 2633 } 2634 2635 /* 2636 * Set up the magic number and version in the Obj_Entry. These 2637 * were checked in the crt1.o from the original ElfKit, so we 2638 * set them for backward compatibility. 2639 */ 2640 obj->magic = RTLD_MAGIC; 2641 obj->version = RTLD_VERSION; 2642 2643 return (0); 2644 } 2645 2646 /* 2647 * Relocate newly-loaded shared objects. The argument is a pointer to 2648 * the Obj_Entry for the first such object. All objects from the first 2649 * to the end of the list of objects are relocated. Returns 0 on success, 2650 * or -1 on failure. 2651 */ 2652 static int 2653 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, 2654 int flags, RtldLockState *lockstate) 2655 { 2656 Obj_Entry *obj; 2657 int error; 2658 2659 for (error = 0, obj = first; obj != NULL; obj = obj->next) { 2660 error = relocate_object(obj, bind_now, rtldobj, flags, 2661 lockstate); 2662 if (error == -1) 2663 break; 2664 } 2665 return (error); 2666 } 2667 2668 /* 2669 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots 2670 * referencing STT_GNU_IFUNC symbols is postponed till the other 2671 * relocations are done. The indirect functions specified as 2672 * ifunc are allowed to call other symbols, so we need to have 2673 * objects relocated before asking for resolution from indirects. 2674 * 2675 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, 2676 * instead of the usual lazy handling of PLT slots. It is 2677 * consistent with how GNU does it. 2678 */ 2679 static int 2680 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, 2681 RtldLockState *lockstate) 2682 { 2683 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1) 2684 return (-1); 2685 if ((obj->bind_now || bind_now) && obj->gnu_ifunc && 2686 reloc_gnu_ifunc(obj, flags, lockstate) == -1) 2687 return (-1); 2688 return (0); 2689 } 2690 2691 static int 2692 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags, 2693 RtldLockState *lockstate) 2694 { 2695 Obj_Entry *obj; 2696 2697 for (obj = first; obj != NULL; obj = obj->next) { 2698 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) 2699 return (-1); 2700 } 2701 return (0); 2702 } 2703 2704 static int 2705 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, 2706 RtldLockState *lockstate) 2707 { 2708 Objlist_Entry *elm; 2709 2710 STAILQ_FOREACH(elm, list, link) { 2711 if (resolve_object_ifunc(elm->obj, bind_now, flags, 2712 lockstate) == -1) 2713 return (-1); 2714 } 2715 return (0); 2716 } 2717 2718 /* 2719 * Cleanup procedure. It will be called (by the atexit mechanism) just 2720 * before the process exits. 2721 */ 2722 static void 2723 rtld_exit(void) 2724 { 2725 RtldLockState lockstate; 2726 2727 wlock_acquire(rtld_bind_lock, &lockstate); 2728 dbg("rtld_exit()"); 2729 objlist_call_fini(&list_fini, NULL, &lockstate); 2730 /* No need to remove the items from the list, since we are exiting. */ 2731 if (!libmap_disable) 2732 lm_fini(); 2733 lock_release(rtld_bind_lock, &lockstate); 2734 } 2735 2736 /* 2737 * Iterate over a search path, translate each element, and invoke the 2738 * callback on the result. 2739 */ 2740 static void * 2741 path_enumerate(const char *path, path_enum_proc callback, void *arg) 2742 { 2743 const char *trans; 2744 if (path == NULL) 2745 return (NULL); 2746 2747 path += strspn(path, ":;"); 2748 while (*path != '\0') { 2749 size_t len; 2750 char *res; 2751 2752 len = strcspn(path, ":;"); 2753 trans = lm_findn(NULL, path, len); 2754 if (trans) 2755 res = callback(trans, strlen(trans), arg); 2756 else 2757 res = callback(path, len, arg); 2758 2759 if (res != NULL) 2760 return (res); 2761 2762 path += len; 2763 path += strspn(path, ":;"); 2764 } 2765 2766 return (NULL); 2767 } 2768 2769 struct try_library_args { 2770 const char *name; 2771 size_t namelen; 2772 char *buffer; 2773 size_t buflen; 2774 }; 2775 2776 static void * 2777 try_library_path(const char *dir, size_t dirlen, void *param) 2778 { 2779 struct try_library_args *arg; 2780 2781 arg = param; 2782 if (*dir == '/' || trust) { 2783 char *pathname; 2784 2785 if (dirlen + 1 + arg->namelen + 1 > arg->buflen) 2786 return (NULL); 2787 2788 pathname = arg->buffer; 2789 strncpy(pathname, dir, dirlen); 2790 pathname[dirlen] = '/'; 2791 strcpy(pathname + dirlen + 1, arg->name); 2792 2793 dbg(" Trying \"%s\"", pathname); 2794 if (access(pathname, F_OK) == 0) { /* We found it */ 2795 pathname = xmalloc(dirlen + 1 + arg->namelen + 1); 2796 strcpy(pathname, arg->buffer); 2797 return (pathname); 2798 } 2799 } 2800 return (NULL); 2801 } 2802 2803 static char * 2804 search_library_path(const char *name, const char *path) 2805 { 2806 char *p; 2807 struct try_library_args arg; 2808 2809 if (path == NULL) 2810 return NULL; 2811 2812 arg.name = name; 2813 arg.namelen = strlen(name); 2814 arg.buffer = xmalloc(PATH_MAX); 2815 arg.buflen = PATH_MAX; 2816 2817 p = path_enumerate(path, try_library_path, &arg); 2818 2819 free(arg.buffer); 2820 2821 return (p); 2822 } 2823 2824 2825 /* 2826 * Finds the library with the given name using the directory descriptors 2827 * listed in the LD_LIBRARY_PATH_FDS environment variable. 2828 * 2829 * Returns a freshly-opened close-on-exec file descriptor for the library, 2830 * or -1 if the library cannot be found. 2831 */ 2832 static char * 2833 search_library_pathfds(const char *name, const char *path, int *fdp) 2834 { 2835 char *envcopy, *fdstr, *found, *last_token; 2836 size_t len; 2837 int dirfd, fd; 2838 2839 dbg("%s('%s', '%s', fdp)", __func__, name, path); 2840 2841 /* Don't load from user-specified libdirs into setuid binaries. */ 2842 if (!trust) 2843 return (NULL); 2844 2845 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ 2846 if (path == NULL) 2847 return (NULL); 2848 2849 /* LD_LIBRARY_PATH_FDS only works with relative paths. */ 2850 if (name[0] == '/') { 2851 dbg("Absolute path (%s) passed to %s", name, __func__); 2852 return (NULL); 2853 } 2854 2855 /* 2856 * Use strtok_r() to walk the FD:FD:FD list. This requires a local 2857 * copy of the path, as strtok_r rewrites separator tokens 2858 * with '\0'. 2859 */ 2860 found = NULL; 2861 envcopy = xstrdup(path); 2862 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; 2863 fdstr = strtok_r(NULL, ":", &last_token)) { 2864 dirfd = parse_libdir(fdstr); 2865 if (dirfd < 0) 2866 break; 2867 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); 2868 if (fd >= 0) { 2869 *fdp = fd; 2870 len = strlen(fdstr) + strlen(name) + 3; 2871 found = xmalloc(len); 2872 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { 2873 _rtld_error("error generating '%d/%s'", 2874 dirfd, name); 2875 rtld_die(); 2876 } 2877 dbg("open('%s') => %d", found, fd); 2878 break; 2879 } 2880 } 2881 free(envcopy); 2882 2883 return (found); 2884 } 2885 2886 2887 int 2888 dlclose(void *handle) 2889 { 2890 Obj_Entry *root; 2891 RtldLockState lockstate; 2892 2893 wlock_acquire(rtld_bind_lock, &lockstate); 2894 root = dlcheck(handle); 2895 if (root == NULL) { 2896 lock_release(rtld_bind_lock, &lockstate); 2897 return -1; 2898 } 2899 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, 2900 root->path); 2901 2902 /* Unreference the object and its dependencies. */ 2903 root->dl_refcount--; 2904 2905 if (root->refcount == 1) { 2906 /* 2907 * The object will be no longer referenced, so we must unload it. 2908 * First, call the fini functions. 2909 */ 2910 objlist_call_fini(&list_fini, root, &lockstate); 2911 2912 unref_dag(root); 2913 2914 /* Finish cleaning up the newly-unreferenced objects. */ 2915 GDB_STATE(RT_DELETE,&root->linkmap); 2916 unload_object(root); 2917 GDB_STATE(RT_CONSISTENT,NULL); 2918 } else 2919 unref_dag(root); 2920 2921 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); 2922 lock_release(rtld_bind_lock, &lockstate); 2923 return 0; 2924 } 2925 2926 char * 2927 dlerror(void) 2928 { 2929 char *msg = error_message; 2930 error_message = NULL; 2931 return msg; 2932 } 2933 2934 /* 2935 * This function is deprecated and has no effect. 2936 */ 2937 void 2938 dllockinit(void *context, 2939 void *(*lock_create)(void *context), 2940 void (*rlock_acquire)(void *lock), 2941 void (*wlock_acquire)(void *lock), 2942 void (*lock_release)(void *lock), 2943 void (*lock_destroy)(void *lock), 2944 void (*context_destroy)(void *context)) 2945 { 2946 static void *cur_context; 2947 static void (*cur_context_destroy)(void *); 2948 2949 /* Just destroy the context from the previous call, if necessary. */ 2950 if (cur_context_destroy != NULL) 2951 cur_context_destroy(cur_context); 2952 cur_context = context; 2953 cur_context_destroy = context_destroy; 2954 } 2955 2956 void * 2957 dlopen(const char *name, int mode) 2958 { 2959 2960 return (rtld_dlopen(name, -1, mode)); 2961 } 2962 2963 void * 2964 fdlopen(int fd, int mode) 2965 { 2966 2967 return (rtld_dlopen(NULL, fd, mode)); 2968 } 2969 2970 static void * 2971 rtld_dlopen(const char *name, int fd, int mode) 2972 { 2973 RtldLockState lockstate; 2974 int lo_flags; 2975 2976 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); 2977 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; 2978 if (ld_tracing != NULL) { 2979 rlock_acquire(rtld_bind_lock, &lockstate); 2980 if (sigsetjmp(lockstate.env, 0) != 0) 2981 lock_upgrade(rtld_bind_lock, &lockstate); 2982 environ = (char **)*get_program_var_addr("environ", &lockstate); 2983 lock_release(rtld_bind_lock, &lockstate); 2984 } 2985 lo_flags = RTLD_LO_DLOPEN; 2986 if (mode & RTLD_NODELETE) 2987 lo_flags |= RTLD_LO_NODELETE; 2988 if (mode & RTLD_NOLOAD) 2989 lo_flags |= RTLD_LO_NOLOAD; 2990 if (ld_tracing != NULL) 2991 lo_flags |= RTLD_LO_TRACE; 2992 2993 return (dlopen_object(name, fd, obj_main, lo_flags, 2994 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); 2995 } 2996 2997 static void 2998 dlopen_cleanup(Obj_Entry *obj) 2999 { 3000 3001 obj->dl_refcount--; 3002 unref_dag(obj); 3003 if (obj->refcount == 0) 3004 unload_object(obj); 3005 } 3006 3007 static Obj_Entry * 3008 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, 3009 int mode, RtldLockState *lockstate) 3010 { 3011 Obj_Entry **old_obj_tail; 3012 Obj_Entry *obj; 3013 Objlist initlist; 3014 RtldLockState mlockstate; 3015 int result; 3016 3017 objlist_init(&initlist); 3018 3019 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { 3020 wlock_acquire(rtld_bind_lock, &mlockstate); 3021 lockstate = &mlockstate; 3022 } 3023 GDB_STATE(RT_ADD,NULL); 3024 3025 old_obj_tail = obj_tail; 3026 obj = NULL; 3027 if (name == NULL && fd == -1) { 3028 obj = obj_main; 3029 obj->refcount++; 3030 } else { 3031 obj = load_object(name, fd, refobj, lo_flags); 3032 } 3033 3034 if (obj) { 3035 obj->dl_refcount++; 3036 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL) 3037 objlist_push_tail(&list_global, obj); 3038 if (*old_obj_tail != NULL) { /* We loaded something new. */ 3039 assert(*old_obj_tail == obj); 3040 result = load_needed_objects(obj, 3041 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY)); 3042 init_dag(obj); 3043 ref_dag(obj); 3044 if (result != -1) 3045 result = rtld_verify_versions(&obj->dagmembers); 3046 if (result != -1 && ld_tracing) 3047 goto trace; 3048 if (result == -1 || relocate_object_dag(obj, 3049 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, 3050 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3051 lockstate) == -1) { 3052 dlopen_cleanup(obj); 3053 obj = NULL; 3054 } else if (lo_flags & RTLD_LO_EARLY) { 3055 /* 3056 * Do not call the init functions for early loaded 3057 * filtees. The image is still not initialized enough 3058 * for them to work. 3059 * 3060 * Our object is found by the global object list and 3061 * will be ordered among all init calls done right 3062 * before transferring control to main. 3063 */ 3064 } else { 3065 /* Make list of init functions to call. */ 3066 initlist_add_objects(obj, &obj->next, &initlist); 3067 } 3068 /* 3069 * Process all no_delete or global objects here, given 3070 * them own DAGs to prevent their dependencies from being 3071 * unloaded. This has to be done after we have loaded all 3072 * of the dependencies, so that we do not miss any. 3073 */ 3074 if (obj != NULL) 3075 process_z(obj); 3076 } else { 3077 /* 3078 * Bump the reference counts for objects on this DAG. If 3079 * this is the first dlopen() call for the object that was 3080 * already loaded as a dependency, initialize the dag 3081 * starting at it. 3082 */ 3083 init_dag(obj); 3084 ref_dag(obj); 3085 3086 if ((lo_flags & RTLD_LO_TRACE) != 0) 3087 goto trace; 3088 } 3089 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || 3090 obj->z_nodelete) && !obj->ref_nodel) { 3091 dbg("obj %s nodelete", obj->path); 3092 ref_dag(obj); 3093 obj->z_nodelete = obj->ref_nodel = true; 3094 } 3095 } 3096 3097 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, 3098 name); 3099 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); 3100 3101 if (!(lo_flags & RTLD_LO_EARLY)) { 3102 map_stacks_exec(lockstate); 3103 } 3104 3105 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, 3106 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, 3107 lockstate) == -1) { 3108 objlist_clear(&initlist); 3109 dlopen_cleanup(obj); 3110 if (lockstate == &mlockstate) 3111 lock_release(rtld_bind_lock, lockstate); 3112 return (NULL); 3113 } 3114 3115 if (!(lo_flags & RTLD_LO_EARLY)) { 3116 /* Call the init functions. */ 3117 objlist_call_init(&initlist, lockstate); 3118 } 3119 objlist_clear(&initlist); 3120 if (lockstate == &mlockstate) 3121 lock_release(rtld_bind_lock, lockstate); 3122 return obj; 3123 trace: 3124 trace_loaded_objects(obj); 3125 if (lockstate == &mlockstate) 3126 lock_release(rtld_bind_lock, lockstate); 3127 exit(0); 3128 } 3129 3130 static void * 3131 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, 3132 int flags) 3133 { 3134 DoneList donelist; 3135 const Obj_Entry *obj, *defobj; 3136 const Elf_Sym *def; 3137 SymLook req; 3138 RtldLockState lockstate; 3139 tls_index ti; 3140 void *sym; 3141 int res; 3142 3143 def = NULL; 3144 defobj = NULL; 3145 symlook_init(&req, name); 3146 req.ventry = ve; 3147 req.flags = flags | SYMLOOK_IN_PLT; 3148 req.lockstate = &lockstate; 3149 3150 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); 3151 rlock_acquire(rtld_bind_lock, &lockstate); 3152 if (sigsetjmp(lockstate.env, 0) != 0) 3153 lock_upgrade(rtld_bind_lock, &lockstate); 3154 if (handle == NULL || handle == RTLD_NEXT || 3155 handle == RTLD_DEFAULT || handle == RTLD_SELF) { 3156 3157 if ((obj = obj_from_addr(retaddr)) == NULL) { 3158 _rtld_error("Cannot determine caller's shared object"); 3159 lock_release(rtld_bind_lock, &lockstate); 3160 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3161 return NULL; 3162 } 3163 if (handle == NULL) { /* Just the caller's shared object. */ 3164 res = symlook_obj(&req, obj); 3165 if (res == 0) { 3166 def = req.sym_out; 3167 defobj = req.defobj_out; 3168 } 3169 } else if (handle == RTLD_NEXT || /* Objects after caller's */ 3170 handle == RTLD_SELF) { /* ... caller included */ 3171 if (handle == RTLD_NEXT) 3172 obj = obj->next; 3173 for (; obj != NULL; obj = obj->next) { 3174 res = symlook_obj(&req, obj); 3175 if (res == 0) { 3176 if (def == NULL || 3177 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) { 3178 def = req.sym_out; 3179 defobj = req.defobj_out; 3180 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3181 break; 3182 } 3183 } 3184 } 3185 /* 3186 * Search the dynamic linker itself, and possibly resolve the 3187 * symbol from there. This is how the application links to 3188 * dynamic linker services such as dlopen. 3189 */ 3190 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3191 res = symlook_obj(&req, &obj_rtld); 3192 if (res == 0) { 3193 def = req.sym_out; 3194 defobj = req.defobj_out; 3195 } 3196 } 3197 } else { 3198 assert(handle == RTLD_DEFAULT); 3199 res = symlook_default(&req, obj); 3200 if (res == 0) { 3201 defobj = req.defobj_out; 3202 def = req.sym_out; 3203 } 3204 } 3205 } else { 3206 if ((obj = dlcheck(handle)) == NULL) { 3207 lock_release(rtld_bind_lock, &lockstate); 3208 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3209 return NULL; 3210 } 3211 3212 donelist_init(&donelist); 3213 if (obj->mainprog) { 3214 /* Handle obtained by dlopen(NULL, ...) implies global scope. */ 3215 res = symlook_global(&req, &donelist); 3216 if (res == 0) { 3217 def = req.sym_out; 3218 defobj = req.defobj_out; 3219 } 3220 /* 3221 * Search the dynamic linker itself, and possibly resolve the 3222 * symbol from there. This is how the application links to 3223 * dynamic linker services such as dlopen. 3224 */ 3225 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { 3226 res = symlook_obj(&req, &obj_rtld); 3227 if (res == 0) { 3228 def = req.sym_out; 3229 defobj = req.defobj_out; 3230 } 3231 } 3232 } 3233 else { 3234 /* Search the whole DAG rooted at the given object. */ 3235 res = symlook_list(&req, &obj->dagmembers, &donelist); 3236 if (res == 0) { 3237 def = req.sym_out; 3238 defobj = req.defobj_out; 3239 } 3240 } 3241 } 3242 3243 if (def != NULL) { 3244 lock_release(rtld_bind_lock, &lockstate); 3245 3246 /* 3247 * The value required by the caller is derived from the value 3248 * of the symbol. this is simply the relocated value of the 3249 * symbol. 3250 */ 3251 if (ELF_ST_TYPE(def->st_info) == STT_FUNC) 3252 sym = make_function_pointer(def, defobj); 3253 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) 3254 sym = rtld_resolve_ifunc(defobj, def); 3255 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { 3256 ti.ti_module = defobj->tlsindex; 3257 ti.ti_offset = def->st_value; 3258 sym = __tls_get_addr(&ti); 3259 } else 3260 sym = defobj->relocbase + def->st_value; 3261 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); 3262 return (sym); 3263 } 3264 3265 _rtld_error("Undefined symbol \"%s\"", name); 3266 lock_release(rtld_bind_lock, &lockstate); 3267 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); 3268 return NULL; 3269 } 3270 3271 void * 3272 dlsym(void *handle, const char *name) 3273 { 3274 return do_dlsym(handle, name, __builtin_return_address(0), NULL, 3275 SYMLOOK_DLSYM); 3276 } 3277 3278 dlfunc_t 3279 dlfunc(void *handle, const char *name) 3280 { 3281 union { 3282 void *d; 3283 dlfunc_t f; 3284 } rv; 3285 3286 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, 3287 SYMLOOK_DLSYM); 3288 return (rv.f); 3289 } 3290 3291 void * 3292 dlvsym(void *handle, const char *name, const char *version) 3293 { 3294 Ver_Entry ventry; 3295 3296 ventry.name = version; 3297 ventry.file = NULL; 3298 ventry.hash = elf_hash(version); 3299 ventry.flags= 0; 3300 return do_dlsym(handle, name, __builtin_return_address(0), &ventry, 3301 SYMLOOK_DLSYM); 3302 } 3303 3304 int 3305 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) 3306 { 3307 const Obj_Entry *obj; 3308 RtldLockState lockstate; 3309 3310 rlock_acquire(rtld_bind_lock, &lockstate); 3311 obj = obj_from_addr(addr); 3312 if (obj == NULL) { 3313 _rtld_error("No shared object contains address"); 3314 lock_release(rtld_bind_lock, &lockstate); 3315 return (0); 3316 } 3317 rtld_fill_dl_phdr_info(obj, phdr_info); 3318 lock_release(rtld_bind_lock, &lockstate); 3319 return (1); 3320 } 3321 3322 int 3323 dladdr(const void *addr, Dl_info *info) 3324 { 3325 const Obj_Entry *obj; 3326 const Elf_Sym *def; 3327 void *symbol_addr; 3328 unsigned long symoffset; 3329 RtldLockState lockstate; 3330 3331 rlock_acquire(rtld_bind_lock, &lockstate); 3332 obj = obj_from_addr(addr); 3333 if (obj == NULL) { 3334 _rtld_error("No shared object contains address"); 3335 lock_release(rtld_bind_lock, &lockstate); 3336 return 0; 3337 } 3338 info->dli_fname = obj->path; 3339 info->dli_fbase = obj->mapbase; 3340 info->dli_saddr = (void *)0; 3341 info->dli_sname = NULL; 3342 3343 /* 3344 * Walk the symbol list looking for the symbol whose address is 3345 * closest to the address sent in. 3346 */ 3347 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { 3348 def = obj->symtab + symoffset; 3349 3350 /* 3351 * For skip the symbol if st_shndx is either SHN_UNDEF or 3352 * SHN_COMMON. 3353 */ 3354 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) 3355 continue; 3356 3357 /* 3358 * If the symbol is greater than the specified address, or if it 3359 * is further away from addr than the current nearest symbol, 3360 * then reject it. 3361 */ 3362 symbol_addr = obj->relocbase + def->st_value; 3363 if (symbol_addr > addr || symbol_addr < info->dli_saddr) 3364 continue; 3365 3366 /* Update our idea of the nearest symbol. */ 3367 info->dli_sname = obj->strtab + def->st_name; 3368 info->dli_saddr = symbol_addr; 3369 3370 /* Exact match? */ 3371 if (info->dli_saddr == addr) 3372 break; 3373 } 3374 lock_release(rtld_bind_lock, &lockstate); 3375 return 1; 3376 } 3377 3378 int 3379 dlinfo(void *handle, int request, void *p) 3380 { 3381 const Obj_Entry *obj; 3382 RtldLockState lockstate; 3383 int error; 3384 3385 rlock_acquire(rtld_bind_lock, &lockstate); 3386 3387 if (handle == NULL || handle == RTLD_SELF) { 3388 void *retaddr; 3389 3390 retaddr = __builtin_return_address(0); /* __GNUC__ only */ 3391 if ((obj = obj_from_addr(retaddr)) == NULL) 3392 _rtld_error("Cannot determine caller's shared object"); 3393 } else 3394 obj = dlcheck(handle); 3395 3396 if (obj == NULL) { 3397 lock_release(rtld_bind_lock, &lockstate); 3398 return (-1); 3399 } 3400 3401 error = 0; 3402 switch (request) { 3403 case RTLD_DI_LINKMAP: 3404 *((struct link_map const **)p) = &obj->linkmap; 3405 break; 3406 case RTLD_DI_ORIGIN: 3407 error = rtld_dirname(obj->path, p); 3408 break; 3409 3410 case RTLD_DI_SERINFOSIZE: 3411 case RTLD_DI_SERINFO: 3412 error = do_search_info(obj, request, (struct dl_serinfo *)p); 3413 break; 3414 3415 default: 3416 _rtld_error("Invalid request %d passed to dlinfo()", request); 3417 error = -1; 3418 } 3419 3420 lock_release(rtld_bind_lock, &lockstate); 3421 3422 return (error); 3423 } 3424 3425 static void 3426 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) 3427 { 3428 3429 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; 3430 phdr_info->dlpi_name = obj->path; 3431 phdr_info->dlpi_phdr = obj->phdr; 3432 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]); 3433 phdr_info->dlpi_tls_modid = obj->tlsindex; 3434 phdr_info->dlpi_tls_data = obj->tlsinit; 3435 phdr_info->dlpi_adds = obj_loads; 3436 phdr_info->dlpi_subs = obj_loads - obj_count; 3437 } 3438 3439 int 3440 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) 3441 { 3442 struct dl_phdr_info phdr_info; 3443 const Obj_Entry *obj; 3444 RtldLockState bind_lockstate, phdr_lockstate; 3445 int error; 3446 3447 wlock_acquire(rtld_phdr_lock, &phdr_lockstate); 3448 rlock_acquire(rtld_bind_lock, &bind_lockstate); 3449 3450 error = 0; 3451 3452 for (obj = obj_list; obj != NULL; obj = obj->next) { 3453 rtld_fill_dl_phdr_info(obj, &phdr_info); 3454 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0) 3455 break; 3456 3457 } 3458 if (error == 0) { 3459 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); 3460 error = callback(&phdr_info, sizeof(phdr_info), param); 3461 } 3462 3463 lock_release(rtld_bind_lock, &bind_lockstate); 3464 lock_release(rtld_phdr_lock, &phdr_lockstate); 3465 3466 return (error); 3467 } 3468 3469 static void * 3470 fill_search_info(const char *dir, size_t dirlen, void *param) 3471 { 3472 struct fill_search_info_args *arg; 3473 3474 arg = param; 3475 3476 if (arg->request == RTLD_DI_SERINFOSIZE) { 3477 arg->serinfo->dls_cnt ++; 3478 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; 3479 } else { 3480 struct dl_serpath *s_entry; 3481 3482 s_entry = arg->serpath; 3483 s_entry->dls_name = arg->strspace; 3484 s_entry->dls_flags = arg->flags; 3485 3486 strncpy(arg->strspace, dir, dirlen); 3487 arg->strspace[dirlen] = '\0'; 3488 3489 arg->strspace += dirlen + 1; 3490 arg->serpath++; 3491 } 3492 3493 return (NULL); 3494 } 3495 3496 static int 3497 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) 3498 { 3499 struct dl_serinfo _info; 3500 struct fill_search_info_args args; 3501 3502 args.request = RTLD_DI_SERINFOSIZE; 3503 args.serinfo = &_info; 3504 3505 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); 3506 _info.dls_cnt = 0; 3507 3508 path_enumerate(obj->rpath, fill_search_info, &args); 3509 path_enumerate(ld_library_path, fill_search_info, &args); 3510 path_enumerate(obj->runpath, fill_search_info, &args); 3511 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args); 3512 if (!obj->z_nodeflib) 3513 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); 3514 3515 3516 if (request == RTLD_DI_SERINFOSIZE) { 3517 info->dls_size = _info.dls_size; 3518 info->dls_cnt = _info.dls_cnt; 3519 return (0); 3520 } 3521 3522 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { 3523 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); 3524 return (-1); 3525 } 3526 3527 args.request = RTLD_DI_SERINFO; 3528 args.serinfo = info; 3529 args.serpath = &info->dls_serpath[0]; 3530 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; 3531 3532 args.flags = LA_SER_RUNPATH; 3533 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) 3534 return (-1); 3535 3536 args.flags = LA_SER_LIBPATH; 3537 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) 3538 return (-1); 3539 3540 args.flags = LA_SER_RUNPATH; 3541 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL) 3542 return (-1); 3543 3544 args.flags = LA_SER_CONFIG; 3545 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args) 3546 != NULL) 3547 return (-1); 3548 3549 args.flags = LA_SER_DEFAULT; 3550 if (!obj->z_nodeflib && 3551 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) 3552 return (-1); 3553 return (0); 3554 } 3555 3556 static int 3557 rtld_dirname(const char *path, char *bname) 3558 { 3559 const char *endp; 3560 3561 /* Empty or NULL string gets treated as "." */ 3562 if (path == NULL || *path == '\0') { 3563 bname[0] = '.'; 3564 bname[1] = '\0'; 3565 return (0); 3566 } 3567 3568 /* Strip trailing slashes */ 3569 endp = path + strlen(path) - 1; 3570 while (endp > path && *endp == '/') 3571 endp--; 3572 3573 /* Find the start of the dir */ 3574 while (endp > path && *endp != '/') 3575 endp--; 3576 3577 /* Either the dir is "/" or there are no slashes */ 3578 if (endp == path) { 3579 bname[0] = *endp == '/' ? '/' : '.'; 3580 bname[1] = '\0'; 3581 return (0); 3582 } else { 3583 do { 3584 endp--; 3585 } while (endp > path && *endp == '/'); 3586 } 3587 3588 if (endp - path + 2 > PATH_MAX) 3589 { 3590 _rtld_error("Filename is too long: %s", path); 3591 return(-1); 3592 } 3593 3594 strncpy(bname, path, endp - path + 1); 3595 bname[endp - path + 1] = '\0'; 3596 return (0); 3597 } 3598 3599 static int 3600 rtld_dirname_abs(const char *path, char *base) 3601 { 3602 char *last; 3603 3604 if (realpath(path, base) == NULL) 3605 return (-1); 3606 dbg("%s -> %s", path, base); 3607 last = strrchr(base, '/'); 3608 if (last == NULL) 3609 return (-1); 3610 if (last != base) 3611 *last = '\0'; 3612 return (0); 3613 } 3614 3615 static void 3616 linkmap_add(Obj_Entry *obj) 3617 { 3618 struct link_map *l = &obj->linkmap; 3619 struct link_map *prev; 3620 3621 obj->linkmap.l_name = obj->path; 3622 obj->linkmap.l_addr = obj->mapbase; 3623 obj->linkmap.l_ld = obj->dynamic; 3624 #ifdef __mips__ 3625 /* GDB needs load offset on MIPS to use the symbols */ 3626 obj->linkmap.l_offs = obj->relocbase; 3627 #endif 3628 3629 if (r_debug.r_map == NULL) { 3630 r_debug.r_map = l; 3631 return; 3632 } 3633 3634 /* 3635 * Scan to the end of the list, but not past the entry for the 3636 * dynamic linker, which we want to keep at the very end. 3637 */ 3638 for (prev = r_debug.r_map; 3639 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; 3640 prev = prev->l_next) 3641 ; 3642 3643 /* Link in the new entry. */ 3644 l->l_prev = prev; 3645 l->l_next = prev->l_next; 3646 if (l->l_next != NULL) 3647 l->l_next->l_prev = l; 3648 prev->l_next = l; 3649 } 3650 3651 static void 3652 linkmap_delete(Obj_Entry *obj) 3653 { 3654 struct link_map *l = &obj->linkmap; 3655 3656 if (l->l_prev == NULL) { 3657 if ((r_debug.r_map = l->l_next) != NULL) 3658 l->l_next->l_prev = NULL; 3659 return; 3660 } 3661 3662 if ((l->l_prev->l_next = l->l_next) != NULL) 3663 l->l_next->l_prev = l->l_prev; 3664 } 3665 3666 /* 3667 * Function for the debugger to set a breakpoint on to gain control. 3668 * 3669 * The two parameters allow the debugger to easily find and determine 3670 * what the runtime loader is doing and to whom it is doing it. 3671 * 3672 * When the loadhook trap is hit (r_debug_state, set at program 3673 * initialization), the arguments can be found on the stack: 3674 * 3675 * +8 struct link_map *m 3676 * +4 struct r_debug *rd 3677 * +0 RetAddr 3678 */ 3679 void 3680 r_debug_state(struct r_debug* rd, struct link_map *m) 3681 { 3682 /* 3683 * The following is a hack to force the compiler to emit calls to 3684 * this function, even when optimizing. If the function is empty, 3685 * the compiler is not obliged to emit any code for calls to it, 3686 * even when marked __noinline. However, gdb depends on those 3687 * calls being made. 3688 */ 3689 __compiler_membar(); 3690 } 3691 3692 /* 3693 * A function called after init routines have completed. This can be used to 3694 * break before a program's entry routine is called, and can be used when 3695 * main is not available in the symbol table. 3696 */ 3697 void 3698 _r_debug_postinit(struct link_map *m) 3699 { 3700 3701 /* See r_debug_state(). */ 3702 __compiler_membar(); 3703 } 3704 3705 /* 3706 * Get address of the pointer variable in the main program. 3707 * Prefer non-weak symbol over the weak one. 3708 */ 3709 static const void ** 3710 get_program_var_addr(const char *name, RtldLockState *lockstate) 3711 { 3712 SymLook req; 3713 DoneList donelist; 3714 3715 symlook_init(&req, name); 3716 req.lockstate = lockstate; 3717 donelist_init(&donelist); 3718 if (symlook_global(&req, &donelist) != 0) 3719 return (NULL); 3720 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) 3721 return ((const void **)make_function_pointer(req.sym_out, 3722 req.defobj_out)); 3723 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) 3724 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); 3725 else 3726 return ((const void **)(req.defobj_out->relocbase + 3727 req.sym_out->st_value)); 3728 } 3729 3730 /* 3731 * Set a pointer variable in the main program to the given value. This 3732 * is used to set key variables such as "environ" before any of the 3733 * init functions are called. 3734 */ 3735 static void 3736 set_program_var(const char *name, const void *value) 3737 { 3738 const void **addr; 3739 3740 if ((addr = get_program_var_addr(name, NULL)) != NULL) { 3741 dbg("\"%s\": *%p <-- %p", name, addr, value); 3742 *addr = value; 3743 } 3744 } 3745 3746 /* 3747 * Search the global objects, including dependencies and main object, 3748 * for the given symbol. 3749 */ 3750 static int 3751 symlook_global(SymLook *req, DoneList *donelist) 3752 { 3753 SymLook req1; 3754 const Objlist_Entry *elm; 3755 int res; 3756 3757 symlook_init_from_req(&req1, req); 3758 3759 /* Search all objects loaded at program start up. */ 3760 if (req->defobj_out == NULL || 3761 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3762 res = symlook_list(&req1, &list_main, donelist); 3763 if (res == 0 && (req->defobj_out == NULL || 3764 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3765 req->sym_out = req1.sym_out; 3766 req->defobj_out = req1.defobj_out; 3767 assert(req->defobj_out != NULL); 3768 } 3769 } 3770 3771 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ 3772 STAILQ_FOREACH(elm, &list_global, link) { 3773 if (req->defobj_out != NULL && 3774 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3775 break; 3776 res = symlook_list(&req1, &elm->obj->dagmembers, donelist); 3777 if (res == 0 && (req->defobj_out == NULL || 3778 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3779 req->sym_out = req1.sym_out; 3780 req->defobj_out = req1.defobj_out; 3781 assert(req->defobj_out != NULL); 3782 } 3783 } 3784 3785 return (req->sym_out != NULL ? 0 : ESRCH); 3786 } 3787 3788 /* 3789 * Given a symbol name in a referencing object, find the corresponding 3790 * definition of the symbol. Returns a pointer to the symbol, or NULL if 3791 * no definition was found. Returns a pointer to the Obj_Entry of the 3792 * defining object via the reference parameter DEFOBJ_OUT. 3793 */ 3794 static int 3795 symlook_default(SymLook *req, const Obj_Entry *refobj) 3796 { 3797 DoneList donelist; 3798 const Objlist_Entry *elm; 3799 SymLook req1; 3800 int res; 3801 3802 donelist_init(&donelist); 3803 symlook_init_from_req(&req1, req); 3804 3805 /* Look first in the referencing object if linked symbolically. */ 3806 if (refobj->symbolic && !donelist_check(&donelist, refobj)) { 3807 res = symlook_obj(&req1, refobj); 3808 if (res == 0) { 3809 req->sym_out = req1.sym_out; 3810 req->defobj_out = req1.defobj_out; 3811 assert(req->defobj_out != NULL); 3812 } 3813 } 3814 3815 symlook_global(req, &donelist); 3816 3817 /* Search all dlopened DAGs containing the referencing object. */ 3818 STAILQ_FOREACH(elm, &refobj->dldags, link) { 3819 if (req->sym_out != NULL && 3820 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK) 3821 break; 3822 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); 3823 if (res == 0 && (req->sym_out == NULL || 3824 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { 3825 req->sym_out = req1.sym_out; 3826 req->defobj_out = req1.defobj_out; 3827 assert(req->defobj_out != NULL); 3828 } 3829 } 3830 3831 /* 3832 * Search the dynamic linker itself, and possibly resolve the 3833 * symbol from there. This is how the application links to 3834 * dynamic linker services such as dlopen. 3835 */ 3836 if (req->sym_out == NULL || 3837 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { 3838 res = symlook_obj(&req1, &obj_rtld); 3839 if (res == 0) { 3840 req->sym_out = req1.sym_out; 3841 req->defobj_out = req1.defobj_out; 3842 assert(req->defobj_out != NULL); 3843 } 3844 } 3845 3846 return (req->sym_out != NULL ? 0 : ESRCH); 3847 } 3848 3849 static int 3850 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) 3851 { 3852 const Elf_Sym *def; 3853 const Obj_Entry *defobj; 3854 const Objlist_Entry *elm; 3855 SymLook req1; 3856 int res; 3857 3858 def = NULL; 3859 defobj = NULL; 3860 STAILQ_FOREACH(elm, objlist, link) { 3861 if (donelist_check(dlp, elm->obj)) 3862 continue; 3863 symlook_init_from_req(&req1, req); 3864 if ((res = symlook_obj(&req1, elm->obj)) == 0) { 3865 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3866 def = req1.sym_out; 3867 defobj = req1.defobj_out; 3868 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3869 break; 3870 } 3871 } 3872 } 3873 if (def != NULL) { 3874 req->sym_out = def; 3875 req->defobj_out = defobj; 3876 return (0); 3877 } 3878 return (ESRCH); 3879 } 3880 3881 /* 3882 * Search the chain of DAGS cointed to by the given Needed_Entry 3883 * for a symbol of the given name. Each DAG is scanned completely 3884 * before advancing to the next one. Returns a pointer to the symbol, 3885 * or NULL if no definition was found. 3886 */ 3887 static int 3888 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) 3889 { 3890 const Elf_Sym *def; 3891 const Needed_Entry *n; 3892 const Obj_Entry *defobj; 3893 SymLook req1; 3894 int res; 3895 3896 def = NULL; 3897 defobj = NULL; 3898 symlook_init_from_req(&req1, req); 3899 for (n = needed; n != NULL; n = n->next) { 3900 if (n->obj == NULL || 3901 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) 3902 continue; 3903 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) { 3904 def = req1.sym_out; 3905 defobj = req1.defobj_out; 3906 if (ELF_ST_BIND(def->st_info) != STB_WEAK) 3907 break; 3908 } 3909 } 3910 if (def != NULL) { 3911 req->sym_out = def; 3912 req->defobj_out = defobj; 3913 return (0); 3914 } 3915 return (ESRCH); 3916 } 3917 3918 /* 3919 * Search the symbol table of a single shared object for a symbol of 3920 * the given name and version, if requested. Returns a pointer to the 3921 * symbol, or NULL if no definition was found. If the object is 3922 * filter, return filtered symbol from filtee. 3923 * 3924 * The symbol's hash value is passed in for efficiency reasons; that 3925 * eliminates many recomputations of the hash value. 3926 */ 3927 int 3928 symlook_obj(SymLook *req, const Obj_Entry *obj) 3929 { 3930 DoneList donelist; 3931 SymLook req1; 3932 int flags, res, mres; 3933 3934 /* 3935 * If there is at least one valid hash at this point, we prefer to 3936 * use the faster GNU version if available. 3937 */ 3938 if (obj->valid_hash_gnu) 3939 mres = symlook_obj1_gnu(req, obj); 3940 else if (obj->valid_hash_sysv) 3941 mres = symlook_obj1_sysv(req, obj); 3942 else 3943 return (EINVAL); 3944 3945 if (mres == 0) { 3946 if (obj->needed_filtees != NULL) { 3947 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3948 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3949 donelist_init(&donelist); 3950 symlook_init_from_req(&req1, req); 3951 res = symlook_needed(&req1, obj->needed_filtees, &donelist); 3952 if (res == 0) { 3953 req->sym_out = req1.sym_out; 3954 req->defobj_out = req1.defobj_out; 3955 } 3956 return (res); 3957 } 3958 if (obj->needed_aux_filtees != NULL) { 3959 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0; 3960 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); 3961 donelist_init(&donelist); 3962 symlook_init_from_req(&req1, req); 3963 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist); 3964 if (res == 0) { 3965 req->sym_out = req1.sym_out; 3966 req->defobj_out = req1.defobj_out; 3967 return (res); 3968 } 3969 } 3970 } 3971 return (mres); 3972 } 3973 3974 /* Symbol match routine common to both hash functions */ 3975 static bool 3976 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, 3977 const unsigned long symnum) 3978 { 3979 Elf_Versym verndx; 3980 const Elf_Sym *symp; 3981 const char *strp; 3982 3983 symp = obj->symtab + symnum; 3984 strp = obj->strtab + symp->st_name; 3985 3986 switch (ELF_ST_TYPE(symp->st_info)) { 3987 case STT_FUNC: 3988 case STT_NOTYPE: 3989 case STT_OBJECT: 3990 case STT_COMMON: 3991 case STT_GNU_IFUNC: 3992 if (symp->st_value == 0) 3993 return (false); 3994 /* fallthrough */ 3995 case STT_TLS: 3996 if (symp->st_shndx != SHN_UNDEF) 3997 break; 3998 #ifndef __mips__ 3999 else if (((req->flags & SYMLOOK_IN_PLT) == 0) && 4000 (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) 4001 break; 4002 /* fallthrough */ 4003 #endif 4004 default: 4005 return (false); 4006 } 4007 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) 4008 return (false); 4009 4010 if (req->ventry == NULL) { 4011 if (obj->versyms != NULL) { 4012 verndx = VER_NDX(obj->versyms[symnum]); 4013 if (verndx > obj->vernum) { 4014 _rtld_error( 4015 "%s: symbol %s references wrong version %d", 4016 obj->path, obj->strtab + symnum, verndx); 4017 return (false); 4018 } 4019 /* 4020 * If we are not called from dlsym (i.e. this 4021 * is a normal relocation from unversioned 4022 * binary), accept the symbol immediately if 4023 * it happens to have first version after this 4024 * shared object became versioned. Otherwise, 4025 * if symbol is versioned and not hidden, 4026 * remember it. If it is the only symbol with 4027 * this name exported by the shared object, it 4028 * will be returned as a match by the calling 4029 * function. If symbol is global (verndx < 2) 4030 * accept it unconditionally. 4031 */ 4032 if ((req->flags & SYMLOOK_DLSYM) == 0 && 4033 verndx == VER_NDX_GIVEN) { 4034 result->sym_out = symp; 4035 return (true); 4036 } 4037 else if (verndx >= VER_NDX_GIVEN) { 4038 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) 4039 == 0) { 4040 if (result->vsymp == NULL) 4041 result->vsymp = symp; 4042 result->vcount++; 4043 } 4044 return (false); 4045 } 4046 } 4047 result->sym_out = symp; 4048 return (true); 4049 } 4050 if (obj->versyms == NULL) { 4051 if (object_match_name(obj, req->ventry->name)) { 4052 _rtld_error("%s: object %s should provide version %s " 4053 "for symbol %s", obj_rtld.path, obj->path, 4054 req->ventry->name, obj->strtab + symnum); 4055 return (false); 4056 } 4057 } else { 4058 verndx = VER_NDX(obj->versyms[symnum]); 4059 if (verndx > obj->vernum) { 4060 _rtld_error("%s: symbol %s references wrong version %d", 4061 obj->path, obj->strtab + symnum, verndx); 4062 return (false); 4063 } 4064 if (obj->vertab[verndx].hash != req->ventry->hash || 4065 strcmp(obj->vertab[verndx].name, req->ventry->name)) { 4066 /* 4067 * Version does not match. Look if this is a 4068 * global symbol and if it is not hidden. If 4069 * global symbol (verndx < 2) is available, 4070 * use it. Do not return symbol if we are 4071 * called by dlvsym, because dlvsym looks for 4072 * a specific version and default one is not 4073 * what dlvsym wants. 4074 */ 4075 if ((req->flags & SYMLOOK_DLSYM) || 4076 (verndx >= VER_NDX_GIVEN) || 4077 (obj->versyms[symnum] & VER_NDX_HIDDEN)) 4078 return (false); 4079 } 4080 } 4081 result->sym_out = symp; 4082 return (true); 4083 } 4084 4085 /* 4086 * Search for symbol using SysV hash function. 4087 * obj->buckets is known not to be NULL at this point; the test for this was 4088 * performed with the obj->valid_hash_sysv assignment. 4089 */ 4090 static int 4091 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) 4092 { 4093 unsigned long symnum; 4094 Sym_Match_Result matchres; 4095 4096 matchres.sym_out = NULL; 4097 matchres.vsymp = NULL; 4098 matchres.vcount = 0; 4099 4100 for (symnum = obj->buckets[req->hash % obj->nbuckets]; 4101 symnum != STN_UNDEF; symnum = obj->chains[symnum]) { 4102 if (symnum >= obj->nchains) 4103 return (ESRCH); /* Bad object */ 4104 4105 if (matched_symbol(req, obj, &matchres, symnum)) { 4106 req->sym_out = matchres.sym_out; 4107 req->defobj_out = obj; 4108 return (0); 4109 } 4110 } 4111 if (matchres.vcount == 1) { 4112 req->sym_out = matchres.vsymp; 4113 req->defobj_out = obj; 4114 return (0); 4115 } 4116 return (ESRCH); 4117 } 4118 4119 /* Search for symbol using GNU hash function */ 4120 static int 4121 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) 4122 { 4123 Elf_Addr bloom_word; 4124 const Elf32_Word *hashval; 4125 Elf32_Word bucket; 4126 Sym_Match_Result matchres; 4127 unsigned int h1, h2; 4128 unsigned long symnum; 4129 4130 matchres.sym_out = NULL; 4131 matchres.vsymp = NULL; 4132 matchres.vcount = 0; 4133 4134 /* Pick right bitmask word from Bloom filter array */ 4135 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & 4136 obj->maskwords_bm_gnu]; 4137 4138 /* Calculate modulus word size of gnu hash and its derivative */ 4139 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); 4140 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); 4141 4142 /* Filter out the "definitely not in set" queries */ 4143 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) 4144 return (ESRCH); 4145 4146 /* Locate hash chain and corresponding value element*/ 4147 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; 4148 if (bucket == 0) 4149 return (ESRCH); 4150 hashval = &obj->chain_zero_gnu[bucket]; 4151 do { 4152 if (((*hashval ^ req->hash_gnu) >> 1) == 0) { 4153 symnum = hashval - obj->chain_zero_gnu; 4154 if (matched_symbol(req, obj, &matchres, symnum)) { 4155 req->sym_out = matchres.sym_out; 4156 req->defobj_out = obj; 4157 return (0); 4158 } 4159 } 4160 } while ((*hashval++ & 1) == 0); 4161 if (matchres.vcount == 1) { 4162 req->sym_out = matchres.vsymp; 4163 req->defobj_out = obj; 4164 return (0); 4165 } 4166 return (ESRCH); 4167 } 4168 4169 static void 4170 trace_loaded_objects(Obj_Entry *obj) 4171 { 4172 char *fmt1, *fmt2, *fmt, *main_local, *list_containers; 4173 int c; 4174 4175 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) 4176 main_local = ""; 4177 4178 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL) 4179 fmt1 = "\t%o => %p (%x)\n"; 4180 4181 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL) 4182 fmt2 = "\t%o (%x)\n"; 4183 4184 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL"); 4185 4186 for (; obj; obj = obj->next) { 4187 Needed_Entry *needed; 4188 char *name, *path; 4189 bool is_lib; 4190 4191 if (list_containers && obj->needed != NULL) 4192 rtld_printf("%s:\n", obj->path); 4193 for (needed = obj->needed; needed; needed = needed->next) { 4194 if (needed->obj != NULL) { 4195 if (needed->obj->traced && !list_containers) 4196 continue; 4197 needed->obj->traced = true; 4198 path = needed->obj->path; 4199 } else 4200 path = "not found"; 4201 4202 name = (char *)obj->strtab + needed->name; 4203 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ 4204 4205 fmt = is_lib ? fmt1 : fmt2; 4206 while ((c = *fmt++) != '\0') { 4207 switch (c) { 4208 default: 4209 rtld_putchar(c); 4210 continue; 4211 case '\\': 4212 switch (c = *fmt) { 4213 case '\0': 4214 continue; 4215 case 'n': 4216 rtld_putchar('\n'); 4217 break; 4218 case 't': 4219 rtld_putchar('\t'); 4220 break; 4221 } 4222 break; 4223 case '%': 4224 switch (c = *fmt) { 4225 case '\0': 4226 continue; 4227 case '%': 4228 default: 4229 rtld_putchar(c); 4230 break; 4231 case 'A': 4232 rtld_putstr(main_local); 4233 break; 4234 case 'a': 4235 rtld_putstr(obj_main->path); 4236 break; 4237 case 'o': 4238 rtld_putstr(name); 4239 break; 4240 #if 0 4241 case 'm': 4242 rtld_printf("%d", sodp->sod_major); 4243 break; 4244 case 'n': 4245 rtld_printf("%d", sodp->sod_minor); 4246 break; 4247 #endif 4248 case 'p': 4249 rtld_putstr(path); 4250 break; 4251 case 'x': 4252 rtld_printf("%p", needed->obj ? needed->obj->mapbase : 4253 0); 4254 break; 4255 } 4256 break; 4257 } 4258 ++fmt; 4259 } 4260 } 4261 } 4262 } 4263 4264 /* 4265 * Unload a dlopened object and its dependencies from memory and from 4266 * our data structures. It is assumed that the DAG rooted in the 4267 * object has already been unreferenced, and that the object has a 4268 * reference count of 0. 4269 */ 4270 static void 4271 unload_object(Obj_Entry *root) 4272 { 4273 Obj_Entry *obj; 4274 Obj_Entry **linkp; 4275 4276 assert(root->refcount == 0); 4277 4278 /* 4279 * Pass over the DAG removing unreferenced objects from 4280 * appropriate lists. 4281 */ 4282 unlink_object(root); 4283 4284 /* Unmap all objects that are no longer referenced. */ 4285 linkp = &obj_list->next; 4286 while ((obj = *linkp) != NULL) { 4287 if (obj->refcount == 0) { 4288 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, 4289 obj->path); 4290 dbg("unloading \"%s\"", obj->path); 4291 unload_filtees(root); 4292 munmap(obj->mapbase, obj->mapsize); 4293 linkmap_delete(obj); 4294 *linkp = obj->next; 4295 obj_count--; 4296 obj_free(obj); 4297 } else 4298 linkp = &obj->next; 4299 } 4300 obj_tail = linkp; 4301 } 4302 4303 static void 4304 unlink_object(Obj_Entry *root) 4305 { 4306 Objlist_Entry *elm; 4307 4308 if (root->refcount == 0) { 4309 /* Remove the object from the RTLD_GLOBAL list. */ 4310 objlist_remove(&list_global, root); 4311 4312 /* Remove the object from all objects' DAG lists. */ 4313 STAILQ_FOREACH(elm, &root->dagmembers, link) { 4314 objlist_remove(&elm->obj->dldags, root); 4315 if (elm->obj != root) 4316 unlink_object(elm->obj); 4317 } 4318 } 4319 } 4320 4321 static void 4322 ref_dag(Obj_Entry *root) 4323 { 4324 Objlist_Entry *elm; 4325 4326 assert(root->dag_inited); 4327 STAILQ_FOREACH(elm, &root->dagmembers, link) 4328 elm->obj->refcount++; 4329 } 4330 4331 static void 4332 unref_dag(Obj_Entry *root) 4333 { 4334 Objlist_Entry *elm; 4335 4336 assert(root->dag_inited); 4337 STAILQ_FOREACH(elm, &root->dagmembers, link) 4338 elm->obj->refcount--; 4339 } 4340 4341 /* 4342 * Common code for MD __tls_get_addr(). 4343 */ 4344 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline; 4345 static void * 4346 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset) 4347 { 4348 Elf_Addr *newdtv, *dtv; 4349 RtldLockState lockstate; 4350 int to_copy; 4351 4352 dtv = *dtvp; 4353 /* Check dtv generation in case new modules have arrived */ 4354 if (dtv[0] != tls_dtv_generation) { 4355 wlock_acquire(rtld_bind_lock, &lockstate); 4356 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4357 to_copy = dtv[1]; 4358 if (to_copy > tls_max_index) 4359 to_copy = tls_max_index; 4360 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); 4361 newdtv[0] = tls_dtv_generation; 4362 newdtv[1] = tls_max_index; 4363 free(dtv); 4364 lock_release(rtld_bind_lock, &lockstate); 4365 dtv = *dtvp = newdtv; 4366 } 4367 4368 /* Dynamically allocate module TLS if necessary */ 4369 if (dtv[index + 1] == 0) { 4370 /* Signal safe, wlock will block out signals. */ 4371 wlock_acquire(rtld_bind_lock, &lockstate); 4372 if (!dtv[index + 1]) 4373 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); 4374 lock_release(rtld_bind_lock, &lockstate); 4375 } 4376 return ((void *)(dtv[index + 1] + offset)); 4377 } 4378 4379 void * 4380 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset) 4381 { 4382 Elf_Addr *dtv; 4383 4384 dtv = *dtvp; 4385 /* Check dtv generation in case new modules have arrived */ 4386 if (__predict_true(dtv[0] == tls_dtv_generation && 4387 dtv[index + 1] != 0)) 4388 return ((void *)(dtv[index + 1] + offset)); 4389 return (tls_get_addr_slow(dtvp, index, offset)); 4390 } 4391 4392 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ 4393 defined(__powerpc__) 4394 4395 /* 4396 * Allocate Static TLS using the Variant I method. 4397 */ 4398 void * 4399 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) 4400 { 4401 Obj_Entry *obj; 4402 char *tcb; 4403 Elf_Addr **tls; 4404 Elf_Addr *dtv; 4405 Elf_Addr addr; 4406 int i; 4407 4408 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) 4409 return (oldtcb); 4410 4411 assert(tcbsize >= TLS_TCB_SIZE); 4412 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize); 4413 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE); 4414 4415 if (oldtcb != NULL) { 4416 memcpy(tls, oldtcb, tls_static_space); 4417 free(oldtcb); 4418 4419 /* Adjust the DTV. */ 4420 dtv = tls[0]; 4421 for (i = 0; i < dtv[1]; i++) { 4422 if (dtv[i+2] >= (Elf_Addr)oldtcb && 4423 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) { 4424 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls; 4425 } 4426 } 4427 } else { 4428 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4429 tls[0] = dtv; 4430 dtv[0] = tls_dtv_generation; 4431 dtv[1] = tls_max_index; 4432 4433 for (obj = objs; obj; obj = obj->next) { 4434 if (obj->tlsoffset > 0) { 4435 addr = (Elf_Addr)tls + obj->tlsoffset; 4436 if (obj->tlsinitsize > 0) 4437 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4438 if (obj->tlssize > obj->tlsinitsize) 4439 memset((void*) (addr + obj->tlsinitsize), 0, 4440 obj->tlssize - obj->tlsinitsize); 4441 dtv[obj->tlsindex + 1] = addr; 4442 } 4443 } 4444 } 4445 4446 return (tcb); 4447 } 4448 4449 void 4450 free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4451 { 4452 Elf_Addr *dtv; 4453 Elf_Addr tlsstart, tlsend; 4454 int dtvsize, i; 4455 4456 assert(tcbsize >= TLS_TCB_SIZE); 4457 4458 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE; 4459 tlsend = tlsstart + tls_static_space; 4460 4461 dtv = *(Elf_Addr **)tlsstart; 4462 dtvsize = dtv[1]; 4463 for (i = 0; i < dtvsize; i++) { 4464 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) { 4465 free((void*)dtv[i+2]); 4466 } 4467 } 4468 free(dtv); 4469 free(tcb); 4470 } 4471 4472 #endif 4473 4474 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) 4475 4476 /* 4477 * Allocate Static TLS using the Variant II method. 4478 */ 4479 void * 4480 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign) 4481 { 4482 Obj_Entry *obj; 4483 size_t size, ralign; 4484 char *tls; 4485 Elf_Addr *dtv, *olddtv; 4486 Elf_Addr segbase, oldsegbase, addr; 4487 int i; 4488 4489 ralign = tcbalign; 4490 if (tls_static_max_align > ralign) 4491 ralign = tls_static_max_align; 4492 size = round(tls_static_space, ralign) + round(tcbsize, ralign); 4493 4494 assert(tcbsize >= 2*sizeof(Elf_Addr)); 4495 tls = malloc_aligned(size, ralign); 4496 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr)); 4497 4498 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign)); 4499 ((Elf_Addr*)segbase)[0] = segbase; 4500 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; 4501 4502 dtv[0] = tls_dtv_generation; 4503 dtv[1] = tls_max_index; 4504 4505 if (oldtls) { 4506 /* 4507 * Copy the static TLS block over whole. 4508 */ 4509 oldsegbase = (Elf_Addr) oldtls; 4510 memcpy((void *)(segbase - tls_static_space), 4511 (const void *)(oldsegbase - tls_static_space), 4512 tls_static_space); 4513 4514 /* 4515 * If any dynamic TLS blocks have been created tls_get_addr(), 4516 * move them over. 4517 */ 4518 olddtv = ((Elf_Addr**)oldsegbase)[1]; 4519 for (i = 0; i < olddtv[1]; i++) { 4520 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) { 4521 dtv[i+2] = olddtv[i+2]; 4522 olddtv[i+2] = 0; 4523 } 4524 } 4525 4526 /* 4527 * We assume that this block was the one we created with 4528 * allocate_initial_tls(). 4529 */ 4530 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); 4531 } else { 4532 for (obj = objs; obj; obj = obj->next) { 4533 if (obj->tlsoffset) { 4534 addr = segbase - obj->tlsoffset; 4535 memset((void*) (addr + obj->tlsinitsize), 4536 0, obj->tlssize - obj->tlsinitsize); 4537 if (obj->tlsinit) 4538 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); 4539 dtv[obj->tlsindex + 1] = addr; 4540 } 4541 } 4542 } 4543 4544 return (void*) segbase; 4545 } 4546 4547 void 4548 free_tls(void *tls, size_t tcbsize, size_t tcbalign) 4549 { 4550 Elf_Addr* dtv; 4551 size_t size, ralign; 4552 int dtvsize, i; 4553 Elf_Addr tlsstart, tlsend; 4554 4555 /* 4556 * Figure out the size of the initial TLS block so that we can 4557 * find stuff which ___tls_get_addr() allocated dynamically. 4558 */ 4559 ralign = tcbalign; 4560 if (tls_static_max_align > ralign) 4561 ralign = tls_static_max_align; 4562 size = round(tls_static_space, ralign); 4563 4564 dtv = ((Elf_Addr**)tls)[1]; 4565 dtvsize = dtv[1]; 4566 tlsend = (Elf_Addr) tls; 4567 tlsstart = tlsend - size; 4568 for (i = 0; i < dtvsize; i++) { 4569 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) { 4570 free_aligned((void *)dtv[i + 2]); 4571 } 4572 } 4573 4574 free_aligned((void *)tlsstart); 4575 free((void*) dtv); 4576 } 4577 4578 #endif 4579 4580 /* 4581 * Allocate TLS block for module with given index. 4582 */ 4583 void * 4584 allocate_module_tls(int index) 4585 { 4586 Obj_Entry* obj; 4587 char* p; 4588 4589 for (obj = obj_list; obj; obj = obj->next) { 4590 if (obj->tlsindex == index) 4591 break; 4592 } 4593 if (!obj) { 4594 _rtld_error("Can't find module with TLS index %d", index); 4595 rtld_die(); 4596 } 4597 4598 p = malloc_aligned(obj->tlssize, obj->tlsalign); 4599 memcpy(p, obj->tlsinit, obj->tlsinitsize); 4600 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); 4601 4602 return p; 4603 } 4604 4605 bool 4606 allocate_tls_offset(Obj_Entry *obj) 4607 { 4608 size_t off; 4609 4610 if (obj->tls_done) 4611 return true; 4612 4613 if (obj->tlssize == 0) { 4614 obj->tls_done = true; 4615 return true; 4616 } 4617 4618 if (obj->tlsindex == 1) 4619 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); 4620 else 4621 off = calculate_tls_offset(tls_last_offset, tls_last_size, 4622 obj->tlssize, obj->tlsalign); 4623 4624 /* 4625 * If we have already fixed the size of the static TLS block, we 4626 * must stay within that size. When allocating the static TLS, we 4627 * leave a small amount of space spare to be used for dynamically 4628 * loading modules which use static TLS. 4629 */ 4630 if (tls_static_space != 0) { 4631 if (calculate_tls_end(off, obj->tlssize) > tls_static_space) 4632 return false; 4633 } else if (obj->tlsalign > tls_static_max_align) { 4634 tls_static_max_align = obj->tlsalign; 4635 } 4636 4637 tls_last_offset = obj->tlsoffset = off; 4638 tls_last_size = obj->tlssize; 4639 obj->tls_done = true; 4640 4641 return true; 4642 } 4643 4644 void 4645 free_tls_offset(Obj_Entry *obj) 4646 { 4647 4648 /* 4649 * If we were the last thing to allocate out of the static TLS 4650 * block, we give our space back to the 'allocator'. This is a 4651 * simplistic workaround to allow libGL.so.1 to be loaded and 4652 * unloaded multiple times. 4653 */ 4654 if (calculate_tls_end(obj->tlsoffset, obj->tlssize) 4655 == calculate_tls_end(tls_last_offset, tls_last_size)) { 4656 tls_last_offset -= obj->tlssize; 4657 tls_last_size = 0; 4658 } 4659 } 4660 4661 void * 4662 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) 4663 { 4664 void *ret; 4665 RtldLockState lockstate; 4666 4667 wlock_acquire(rtld_bind_lock, &lockstate); 4668 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign); 4669 lock_release(rtld_bind_lock, &lockstate); 4670 return (ret); 4671 } 4672 4673 void 4674 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) 4675 { 4676 RtldLockState lockstate; 4677 4678 wlock_acquire(rtld_bind_lock, &lockstate); 4679 free_tls(tcb, tcbsize, tcbalign); 4680 lock_release(rtld_bind_lock, &lockstate); 4681 } 4682 4683 static void 4684 object_add_name(Obj_Entry *obj, const char *name) 4685 { 4686 Name_Entry *entry; 4687 size_t len; 4688 4689 len = strlen(name); 4690 entry = malloc(sizeof(Name_Entry) + len); 4691 4692 if (entry != NULL) { 4693 strcpy(entry->name, name); 4694 STAILQ_INSERT_TAIL(&obj->names, entry, link); 4695 } 4696 } 4697 4698 static int 4699 object_match_name(const Obj_Entry *obj, const char *name) 4700 { 4701 Name_Entry *entry; 4702 4703 STAILQ_FOREACH(entry, &obj->names, link) { 4704 if (strcmp(name, entry->name) == 0) 4705 return (1); 4706 } 4707 return (0); 4708 } 4709 4710 static Obj_Entry * 4711 locate_dependency(const Obj_Entry *obj, const char *name) 4712 { 4713 const Objlist_Entry *entry; 4714 const Needed_Entry *needed; 4715 4716 STAILQ_FOREACH(entry, &list_main, link) { 4717 if (object_match_name(entry->obj, name)) 4718 return entry->obj; 4719 } 4720 4721 for (needed = obj->needed; needed != NULL; needed = needed->next) { 4722 if (strcmp(obj->strtab + needed->name, name) == 0 || 4723 (needed->obj != NULL && object_match_name(needed->obj, name))) { 4724 /* 4725 * If there is DT_NEEDED for the name we are looking for, 4726 * we are all set. Note that object might not be found if 4727 * dependency was not loaded yet, so the function can 4728 * return NULL here. This is expected and handled 4729 * properly by the caller. 4730 */ 4731 return (needed->obj); 4732 } 4733 } 4734 _rtld_error("%s: Unexpected inconsistency: dependency %s not found", 4735 obj->path, name); 4736 rtld_die(); 4737 } 4738 4739 static int 4740 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, 4741 const Elf_Vernaux *vna) 4742 { 4743 const Elf_Verdef *vd; 4744 const char *vername; 4745 4746 vername = refobj->strtab + vna->vna_name; 4747 vd = depobj->verdef; 4748 if (vd == NULL) { 4749 _rtld_error("%s: version %s required by %s not defined", 4750 depobj->path, vername, refobj->path); 4751 return (-1); 4752 } 4753 for (;;) { 4754 if (vd->vd_version != VER_DEF_CURRENT) { 4755 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4756 depobj->path, vd->vd_version); 4757 return (-1); 4758 } 4759 if (vna->vna_hash == vd->vd_hash) { 4760 const Elf_Verdaux *aux = (const Elf_Verdaux *) 4761 ((char *)vd + vd->vd_aux); 4762 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) 4763 return (0); 4764 } 4765 if (vd->vd_next == 0) 4766 break; 4767 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4768 } 4769 if (vna->vna_flags & VER_FLG_WEAK) 4770 return (0); 4771 _rtld_error("%s: version %s required by %s not found", 4772 depobj->path, vername, refobj->path); 4773 return (-1); 4774 } 4775 4776 static int 4777 rtld_verify_object_versions(Obj_Entry *obj) 4778 { 4779 const Elf_Verneed *vn; 4780 const Elf_Verdef *vd; 4781 const Elf_Verdaux *vda; 4782 const Elf_Vernaux *vna; 4783 const Obj_Entry *depobj; 4784 int maxvernum, vernum; 4785 4786 if (obj->ver_checked) 4787 return (0); 4788 obj->ver_checked = true; 4789 4790 maxvernum = 0; 4791 /* 4792 * Walk over defined and required version records and figure out 4793 * max index used by any of them. Do very basic sanity checking 4794 * while there. 4795 */ 4796 vn = obj->verneed; 4797 while (vn != NULL) { 4798 if (vn->vn_version != VER_NEED_CURRENT) { 4799 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry", 4800 obj->path, vn->vn_version); 4801 return (-1); 4802 } 4803 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4804 for (;;) { 4805 vernum = VER_NEED_IDX(vna->vna_other); 4806 if (vernum > maxvernum) 4807 maxvernum = vernum; 4808 if (vna->vna_next == 0) 4809 break; 4810 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4811 } 4812 if (vn->vn_next == 0) 4813 break; 4814 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4815 } 4816 4817 vd = obj->verdef; 4818 while (vd != NULL) { 4819 if (vd->vd_version != VER_DEF_CURRENT) { 4820 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry", 4821 obj->path, vd->vd_version); 4822 return (-1); 4823 } 4824 vernum = VER_DEF_IDX(vd->vd_ndx); 4825 if (vernum > maxvernum) 4826 maxvernum = vernum; 4827 if (vd->vd_next == 0) 4828 break; 4829 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4830 } 4831 4832 if (maxvernum == 0) 4833 return (0); 4834 4835 /* 4836 * Store version information in array indexable by version index. 4837 * Verify that object version requirements are satisfied along the 4838 * way. 4839 */ 4840 obj->vernum = maxvernum + 1; 4841 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); 4842 4843 vd = obj->verdef; 4844 while (vd != NULL) { 4845 if ((vd->vd_flags & VER_FLG_BASE) == 0) { 4846 vernum = VER_DEF_IDX(vd->vd_ndx); 4847 assert(vernum <= maxvernum); 4848 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux); 4849 obj->vertab[vernum].hash = vd->vd_hash; 4850 obj->vertab[vernum].name = obj->strtab + vda->vda_name; 4851 obj->vertab[vernum].file = NULL; 4852 obj->vertab[vernum].flags = 0; 4853 } 4854 if (vd->vd_next == 0) 4855 break; 4856 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next); 4857 } 4858 4859 vn = obj->verneed; 4860 while (vn != NULL) { 4861 depobj = locate_dependency(obj, obj->strtab + vn->vn_file); 4862 if (depobj == NULL) 4863 return (-1); 4864 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux); 4865 for (;;) { 4866 if (check_object_provided_version(obj, depobj, vna)) 4867 return (-1); 4868 vernum = VER_NEED_IDX(vna->vna_other); 4869 assert(vernum <= maxvernum); 4870 obj->vertab[vernum].hash = vna->vna_hash; 4871 obj->vertab[vernum].name = obj->strtab + vna->vna_name; 4872 obj->vertab[vernum].file = obj->strtab + vn->vn_file; 4873 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ? 4874 VER_INFO_HIDDEN : 0; 4875 if (vna->vna_next == 0) 4876 break; 4877 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next); 4878 } 4879 if (vn->vn_next == 0) 4880 break; 4881 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next); 4882 } 4883 return 0; 4884 } 4885 4886 static int 4887 rtld_verify_versions(const Objlist *objlist) 4888 { 4889 Objlist_Entry *entry; 4890 int rc; 4891 4892 rc = 0; 4893 STAILQ_FOREACH(entry, objlist, link) { 4894 /* 4895 * Skip dummy objects or objects that have their version requirements 4896 * already checked. 4897 */ 4898 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) 4899 continue; 4900 if (rtld_verify_object_versions(entry->obj) == -1) { 4901 rc = -1; 4902 if (ld_tracing == NULL) 4903 break; 4904 } 4905 } 4906 if (rc == 0 || ld_tracing != NULL) 4907 rc = rtld_verify_object_versions(&obj_rtld); 4908 return rc; 4909 } 4910 4911 const Ver_Entry * 4912 fetch_ventry(const Obj_Entry *obj, unsigned long symnum) 4913 { 4914 Elf_Versym vernum; 4915 4916 if (obj->vertab) { 4917 vernum = VER_NDX(obj->versyms[symnum]); 4918 if (vernum >= obj->vernum) { 4919 _rtld_error("%s: symbol %s has wrong verneed value %d", 4920 obj->path, obj->strtab + symnum, vernum); 4921 } else if (obj->vertab[vernum].hash != 0) { 4922 return &obj->vertab[vernum]; 4923 } 4924 } 4925 return NULL; 4926 } 4927 4928 int 4929 _rtld_get_stack_prot(void) 4930 { 4931 4932 return (stack_prot); 4933 } 4934 4935 int 4936 _rtld_is_dlopened(void *arg) 4937 { 4938 Obj_Entry *obj; 4939 RtldLockState lockstate; 4940 int res; 4941 4942 rlock_acquire(rtld_bind_lock, &lockstate); 4943 obj = dlcheck(arg); 4944 if (obj == NULL) 4945 obj = obj_from_addr(arg); 4946 if (obj == NULL) { 4947 _rtld_error("No shared object contains address"); 4948 lock_release(rtld_bind_lock, &lockstate); 4949 return (-1); 4950 } 4951 res = obj->dlopened ? 1 : 0; 4952 lock_release(rtld_bind_lock, &lockstate); 4953 return (res); 4954 } 4955 4956 static void 4957 map_stacks_exec(RtldLockState *lockstate) 4958 { 4959 void (*thr_map_stacks_exec)(void); 4960 4961 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) 4962 return; 4963 thr_map_stacks_exec = (void (*)(void))(uintptr_t) 4964 get_program_var_addr("__pthread_map_stacks_exec", lockstate); 4965 if (thr_map_stacks_exec != NULL) { 4966 stack_prot |= PROT_EXEC; 4967 thr_map_stacks_exec(); 4968 } 4969 } 4970 4971 void 4972 symlook_init(SymLook *dst, const char *name) 4973 { 4974 4975 bzero(dst, sizeof(*dst)); 4976 dst->name = name; 4977 dst->hash = elf_hash(name); 4978 dst->hash_gnu = gnu_hash(name); 4979 } 4980 4981 static void 4982 symlook_init_from_req(SymLook *dst, const SymLook *src) 4983 { 4984 4985 dst->name = src->name; 4986 dst->hash = src->hash; 4987 dst->hash_gnu = src->hash_gnu; 4988 dst->ventry = src->ventry; 4989 dst->flags = src->flags; 4990 dst->defobj_out = NULL; 4991 dst->sym_out = NULL; 4992 dst->lockstate = src->lockstate; 4993 } 4994 4995 4996 /* 4997 * Parse a file descriptor number without pulling in more of libc (e.g. atoi). 4998 */ 4999 static int 5000 parse_libdir(const char *str) 5001 { 5002 static const int RADIX = 10; /* XXXJA: possibly support hex? */ 5003 const char *orig; 5004 int fd; 5005 char c; 5006 5007 orig = str; 5008 fd = 0; 5009 for (c = *str; c != '\0'; c = *++str) { 5010 if (c < '0' || c > '9') 5011 return (-1); 5012 5013 fd *= RADIX; 5014 fd += c - '0'; 5015 } 5016 5017 /* Make sure we actually parsed something. */ 5018 if (str == orig) { 5019 _rtld_error("failed to parse directory FD from '%s'", str); 5020 return (-1); 5021 } 5022 return (fd); 5023 } 5024 5025 /* 5026 * Overrides for libc_pic-provided functions. 5027 */ 5028 5029 int 5030 __getosreldate(void) 5031 { 5032 size_t len; 5033 int oid[2]; 5034 int error, osrel; 5035 5036 if (osreldate != 0) 5037 return (osreldate); 5038 5039 oid[0] = CTL_KERN; 5040 oid[1] = KERN_OSRELDATE; 5041 osrel = 0; 5042 len = sizeof(osrel); 5043 error = sysctl(oid, 2, &osrel, &len, NULL, 0); 5044 if (error == 0 && osrel > 0 && len == sizeof(osrel)) 5045 osreldate = osrel; 5046 return (osreldate); 5047 } 5048 5049 void 5050 exit(int status) 5051 { 5052 5053 _exit(status); 5054 } 5055 5056 void (*__cleanup)(void); 5057 int __isthreaded = 0; 5058 int _thread_autoinit_dummy_decl = 1; 5059 5060 /* 5061 * No unresolved symbols for rtld. 5062 */ 5063 void 5064 __pthread_cxa_finalize(struct dl_phdr_info *a) 5065 { 5066 } 5067 5068 void 5069 __stack_chk_fail(void) 5070 { 5071 5072 _rtld_error("stack overflow detected; terminated"); 5073 rtld_die(); 5074 } 5075 __weak_reference(__stack_chk_fail, __stack_chk_fail_local); 5076 5077 void 5078 __chk_fail(void) 5079 { 5080 5081 _rtld_error("buffer overflow detected; terminated"); 5082 rtld_die(); 5083 } 5084 5085 const char * 5086 rtld_strerror(int errnum) 5087 { 5088 5089 if (errnum < 0 || errnum >= sys_nerr) 5090 return ("Unknown error"); 5091 return (sys_errlist[errnum]); 5092 } 5093