| 1 | /*- |
| 2 | * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. |
| 3 | * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>. |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions |
| 8 | * are met: |
| 9 | * 1. Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * |
| 15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 25 | * |
| 26 | * $FreeBSD: src/libexec/rtld-elf/rtld.c,v 1.43.2.15 2003/02/20 20:42:46 kan Exp $ |
| 27 | * $DragonFly: src/libexec/rtld-elf/rtld.c,v 1.23 2005/05/11 19:47:06 dillon Exp $ |
| 28 | */ |
| 29 | |
| 30 | /* |
| 31 | * Dynamic linker for ELF. |
| 32 | * |
| 33 | * John Polstra <jdp@polstra.com>. |
| 34 | */ |
| 35 | |
| 36 | #ifndef __GNUC__ |
| 37 | #error "GCC is needed to compile this file" |
| 38 | #endif |
| 39 | |
| 40 | #include <sys/param.h> |
| 41 | #include <sys/mman.h> |
| 42 | #include <sys/stat.h> |
| 43 | #include <sys/resident.h> |
| 44 | #include <sys/tls.h> |
| 45 | |
| 46 | #include <machine/tls.h> |
| 47 | |
| 48 | #include <dlfcn.h> |
| 49 | #include <err.h> |
| 50 | #include <errno.h> |
| 51 | #include <fcntl.h> |
| 52 | #include <stdarg.h> |
| 53 | #include <stdio.h> |
| 54 | #include <stdlib.h> |
| 55 | #include <string.h> |
| 56 | #include <unistd.h> |
| 57 | |
| 58 | #include "debug.h" |
| 59 | #include "rtld.h" |
| 60 | |
| 61 | #define PATH_RTLD "/usr/libexec/ld-elf.so.2" |
| 62 | #define LD_ARY_CACHE 16 |
| 63 | |
| 64 | /* Types. */ |
| 65 | typedef void (*func_ptr_type)(); |
| 66 | typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg); |
| 67 | |
| 68 | /* |
| 69 | * This structure provides a reentrant way to keep a list of objects and |
| 70 | * check which ones have already been processed in some way. |
| 71 | */ |
| 72 | typedef struct Struct_DoneList { |
| 73 | const Obj_Entry **objs; /* Array of object pointers */ |
| 74 | unsigned int num_alloc; /* Allocated size of the array */ |
| 75 | unsigned int num_used; /* Number of array slots used */ |
| 76 | } DoneList; |
| 77 | |
| 78 | /* |
| 79 | * Function declarations. |
| 80 | */ |
| 81 | static void die(void); |
| 82 | static void digest_dynamic(Obj_Entry *); |
| 83 | static const char *_getenv_ld(const char *id); |
| 84 | static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); |
| 85 | static Obj_Entry *dlcheck(void *); |
| 86 | static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); |
| 87 | static bool donelist_check(DoneList *, const Obj_Entry *); |
| 88 | static void errmsg_restore(char *); |
| 89 | static char *errmsg_save(void); |
| 90 | static void *fill_search_info(const char *, size_t, void *); |
| 91 | static char *find_library(const char *, const Obj_Entry *); |
| 92 | static Obj_Entry *find_object(const char *); |
| 93 | static Obj_Entry *find_object2(const char *, int *, struct stat *); |
| 94 | static const char *gethints(void); |
| 95 | static void init_dag(Obj_Entry *); |
| 96 | static void init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *); |
| 97 | static void init_rtld(caddr_t); |
| 98 | static void initlist_add_neededs(Needed_Entry *needed, Objlist *list); |
| 99 | static void initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, |
| 100 | Objlist *list); |
| 101 | static bool is_exported(const Elf_Sym *); |
| 102 | static void linkmap_add(Obj_Entry *); |
| 103 | static void linkmap_delete(Obj_Entry *); |
| 104 | static int load_needed_objects(Obj_Entry *); |
| 105 | static int load_preload_objects(void); |
| 106 | static Obj_Entry *load_object(char *); |
| 107 | static void lock_check(void); |
| 108 | static Obj_Entry *obj_from_addr(const void *); |
| 109 | static void objlist_call_fini(Objlist *); |
| 110 | static void objlist_call_init(Objlist *); |
| 111 | static void objlist_clear(Objlist *); |
| 112 | static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); |
| 113 | static void objlist_init(Objlist *); |
| 114 | static void objlist_push_head(Objlist *, Obj_Entry *); |
| 115 | static void objlist_push_tail(Objlist *, Obj_Entry *); |
| 116 | static void objlist_remove(Objlist *, Obj_Entry *); |
| 117 | static void objlist_remove_unref(Objlist *); |
| 118 | static void *path_enumerate(const char *, path_enum_proc, void *); |
| 119 | static int relocate_objects(Obj_Entry *, bool); |
| 120 | static int rtld_dirname(const char *, char *); |
| 121 | static void rtld_exit(void); |
| 122 | static char *search_library_path(const char *, const char *); |
| 123 | static const void **get_program_var_addr(const char *name); |
| 124 | static void set_program_var(const char *, const void *); |
| 125 | static const Elf_Sym *symlook_default(const char *, unsigned long hash, |
| 126 | const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt); |
| 127 | static const Elf_Sym *symlook_list(const char *, unsigned long, |
| 128 | Objlist *, const Obj_Entry **, bool in_plt, DoneList *); |
| 129 | static void trace_loaded_objects(Obj_Entry *obj); |
| 130 | static void unlink_object(Obj_Entry *); |
| 131 | static void unload_object(Obj_Entry *); |
| 132 | static void unref_dag(Obj_Entry *); |
| 133 | |
| 134 | void r_debug_state(struct r_debug*, struct link_map*); |
| 135 | |
| 136 | /* |
| 137 | * Data declarations. |
| 138 | */ |
| 139 | static char *error_message; /* Message for dlerror(), or NULL */ |
| 140 | struct r_debug r_debug; /* for GDB; */ |
| 141 | static bool trust; /* False for setuid and setgid programs */ |
| 142 | static const char *ld_bind_now; /* Environment variable for immediate binding */ |
| 143 | static const char *ld_debug; /* Environment variable for debugging */ |
| 144 | static const char *ld_library_path; /* Environment variable for search path */ |
| 145 | static char *ld_preload; /* Environment variable for libraries to |
| 146 | load first */ |
| 147 | static const char *ld_tracing; /* Called from ldd(1) to print libs */ |
| 148 | static Obj_Entry *obj_list; /* Head of linked list of shared objects */ |
| 149 | static Obj_Entry **obj_tail; /* Link field of last object in list */ |
| 150 | static Obj_Entry **preload_tail; |
| 151 | static Obj_Entry *obj_main; /* The main program shared object */ |
| 152 | static Obj_Entry obj_rtld; /* The dynamic linker shared object */ |
| 153 | static unsigned int obj_count; /* Number of objects in obj_list */ |
| 154 | static int ld_resident; /* Non-zero if resident */ |
| 155 | static const char *ld_ary[LD_ARY_CACHE]; |
| 156 | static int ld_index; |
| 157 | static Objlist initlist; |
| 158 | |
| 159 | static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ |
| 160 | STAILQ_HEAD_INITIALIZER(list_global); |
| 161 | static Objlist list_main = /* Objects loaded at program startup */ |
| 162 | STAILQ_HEAD_INITIALIZER(list_main); |
| 163 | static Objlist list_fini = /* Objects needing fini() calls */ |
| 164 | STAILQ_HEAD_INITIALIZER(list_fini); |
| 165 | |
| 166 | static LockInfo lockinfo; |
| 167 | |
| 168 | static Elf_Sym sym_zero; /* For resolving undefined weak refs. */ |
| 169 | |
| 170 | #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m); |
| 171 | |
| 172 | extern Elf_Dyn _DYNAMIC; |
| 173 | #pragma weak _DYNAMIC |
| 174 | |
| 175 | /* |
| 176 | * These are the functions the dynamic linker exports to application |
| 177 | * programs. They are the only symbols the dynamic linker is willing |
| 178 | * to export from itself. |
| 179 | */ |
| 180 | static func_ptr_type exports[] = { |
| 181 | (func_ptr_type) &_rtld_error, |
| 182 | (func_ptr_type) &dlclose, |
| 183 | (func_ptr_type) &dlerror, |
| 184 | (func_ptr_type) &dlopen, |
| 185 | (func_ptr_type) &dlsym, |
| 186 | (func_ptr_type) &dladdr, |
| 187 | (func_ptr_type) &dlinfo, |
| 188 | #ifdef __i386__ |
| 189 | (func_ptr_type) &___tls_get_addr, |
| 190 | #endif |
| 191 | (func_ptr_type) &__tls_get_addr, |
| 192 | (func_ptr_type) &__tls_get_addr_tcb, |
| 193 | (func_ptr_type) &_rtld_allocate_tls, |
| 194 | (func_ptr_type) &_rtld_free_tls, |
| 195 | (func_ptr_type) &_rtld_call_init, |
| 196 | NULL |
| 197 | }; |
| 198 | |
| 199 | /* |
| 200 | * Global declarations normally provided by crt1. The dynamic linker is |
| 201 | * not built with crt1, so we have to provide them ourselves. |
| 202 | */ |
| 203 | char *__progname; |
| 204 | char **environ; |
| 205 | |
| 206 | /* |
| 207 | * Globals to control TLS allocation. |
| 208 | */ |
| 209 | size_t tls_last_offset; /* Static TLS offset of last module */ |
| 210 | size_t tls_last_size; /* Static TLS size of last module */ |
| 211 | size_t tls_static_space; /* Static TLS space allocated */ |
| 212 | int tls_dtv_generation = 1; /* Used to detect when dtv size changes */ |
| 213 | int tls_max_index = 1; /* Largest module index allocated */ |
| 214 | |
| 215 | /* |
| 216 | * Fill in a DoneList with an allocation large enough to hold all of |
| 217 | * the currently-loaded objects. Keep this as a macro since it calls |
| 218 | * alloca and we want that to occur within the scope of the caller. |
| 219 | */ |
| 220 | #define donelist_init(dlp) \ |
| 221 | ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \ |
| 222 | assert((dlp)->objs != NULL), \ |
| 223 | (dlp)->num_alloc = obj_count, \ |
| 224 | (dlp)->num_used = 0) |
| 225 | |
| 226 | static __inline void |
| 227 | rlock_acquire(void) |
| 228 | { |
| 229 | lockinfo.rlock_acquire(lockinfo.thelock); |
| 230 | atomic_incr_int(&lockinfo.rcount); |
| 231 | lock_check(); |
| 232 | } |
| 233 | |
| 234 | static __inline void |
| 235 | wlock_acquire(void) |
| 236 | { |
| 237 | lockinfo.wlock_acquire(lockinfo.thelock); |
| 238 | atomic_incr_int(&lockinfo.wcount); |
| 239 | lock_check(); |
| 240 | } |
| 241 | |
| 242 | static __inline void |
| 243 | rlock_release(void) |
| 244 | { |
| 245 | atomic_decr_int(&lockinfo.rcount); |
| 246 | lockinfo.rlock_release(lockinfo.thelock); |
| 247 | } |
| 248 | |
| 249 | static __inline void |
| 250 | wlock_release(void) |
| 251 | { |
| 252 | atomic_decr_int(&lockinfo.wcount); |
| 253 | lockinfo.wlock_release(lockinfo.thelock); |
| 254 | } |
| 255 | |
| 256 | /* |
| 257 | * Main entry point for dynamic linking. The first argument is the |
| 258 | * stack pointer. The stack is expected to be laid out as described |
| 259 | * in the SVR4 ABI specification, Intel 386 Processor Supplement. |
| 260 | * Specifically, the stack pointer points to a word containing |
| 261 | * ARGC. Following that in the stack is a null-terminated sequence |
| 262 | * of pointers to argument strings. Then comes a null-terminated |
| 263 | * sequence of pointers to environment strings. Finally, there is a |
| 264 | * sequence of "auxiliary vector" entries. |
| 265 | * |
| 266 | * The second argument points to a place to store the dynamic linker's |
| 267 | * exit procedure pointer and the third to a place to store the main |
| 268 | * program's object. |
| 269 | * |
| 270 | * The return value is the main program's entry point. |
| 271 | */ |
| 272 | |
| 273 | func_ptr_type |
| 274 | _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) |
| 275 | { |
| 276 | Elf_Auxinfo *aux_info[AT_COUNT]; |
| 277 | int i; |
| 278 | int argc; |
| 279 | char **argv; |
| 280 | char **env; |
| 281 | Elf_Auxinfo *aux; |
| 282 | Elf_Auxinfo *auxp; |
| 283 | const char *argv0; |
| 284 | Objlist_Entry *entry; |
| 285 | Obj_Entry *obj; |
| 286 | |
| 287 | ld_index = 0; /* don't use old env cache in case we are resident */ |
| 288 | |
| 289 | /* |
| 290 | * On entry, the dynamic linker itself has not been relocated yet. |
| 291 | * Be very careful not to reference any global data until after |
| 292 | * init_rtld has returned. It is OK to reference file-scope statics |
| 293 | * and string constants, and to call static and global functions. |
| 294 | */ |
| 295 | |
| 296 | /* Find the auxiliary vector on the stack. */ |
| 297 | argc = *sp++; |
| 298 | argv = (char **) sp; |
| 299 | sp += argc + 1; /* Skip over arguments and NULL terminator */ |
| 300 | env = (char **) sp; |
| 301 | |
| 302 | /* |
| 303 | * If we aren't already resident we have to dig out some more info. |
| 304 | * Note that auxinfo does not exist when we are resident. |
| 305 | */ |
| 306 | if (ld_resident == 0) { |
| 307 | while (*sp++ != 0) /* Skip over environment, and NULL terminator */ |
| 308 | ; |
| 309 | aux = (Elf_Auxinfo *) sp; |
| 310 | |
| 311 | /* Digest the auxiliary vector. */ |
| 312 | for (i = 0; i < AT_COUNT; i++) |
| 313 | aux_info[i] = NULL; |
| 314 | for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { |
| 315 | if (auxp->a_type < AT_COUNT) |
| 316 | aux_info[auxp->a_type] = auxp; |
| 317 | } |
| 318 | |
| 319 | /* Initialize and relocate ourselves. */ |
| 320 | assert(aux_info[AT_BASE] != NULL); |
| 321 | init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr); |
| 322 | } |
| 323 | |
| 324 | __progname = obj_rtld.path; |
| 325 | argv0 = argv[0] != NULL ? argv[0] : "(null)"; |
| 326 | environ = env; |
| 327 | |
| 328 | trust = (geteuid() == getuid()) && (getegid() == getgid()); |
| 329 | |
| 330 | ld_bind_now = _getenv_ld("LD_BIND_NOW"); |
| 331 | if (trust) { |
| 332 | ld_debug = _getenv_ld("LD_DEBUG"); |
| 333 | ld_library_path = _getenv_ld("LD_LIBRARY_PATH"); |
| 334 | ld_preload = (char *)_getenv_ld("LD_PRELOAD"); |
| 335 | } |
| 336 | ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS"); |
| 337 | |
| 338 | if (ld_debug != NULL && *ld_debug != '\0') |
| 339 | debug = 1; |
| 340 | dbg("%s is initialized, base address = %p", __progname, |
| 341 | (caddr_t) aux_info[AT_BASE]->a_un.a_ptr); |
| 342 | dbg("RTLD dynamic = %p", obj_rtld.dynamic); |
| 343 | dbg("RTLD pltgot = %p", obj_rtld.pltgot); |
| 344 | |
| 345 | /* |
| 346 | * If we are resident we can skip work that we have already done. |
| 347 | * Note that the stack is reset and there is no Elf_Auxinfo |
| 348 | * when running from a resident image, and the static globals setup |
| 349 | * between here and resident_skip will have already been setup. |
| 350 | */ |
| 351 | if (ld_resident) |
| 352 | goto resident_skip1; |
| 353 | |
| 354 | /* |
| 355 | * Load the main program, or process its program header if it is |
| 356 | * already loaded. |
| 357 | */ |
| 358 | if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */ |
| 359 | int fd = aux_info[AT_EXECFD]->a_un.a_val; |
| 360 | dbg("loading main program"); |
| 361 | obj_main = map_object(fd, argv0, NULL); |
| 362 | close(fd); |
| 363 | if (obj_main == NULL) |
| 364 | die(); |
| 365 | } else { /* Main program already loaded. */ |
| 366 | const Elf_Phdr *phdr; |
| 367 | int phnum; |
| 368 | caddr_t entry; |
| 369 | |
| 370 | dbg("processing main program's program header"); |
| 371 | assert(aux_info[AT_PHDR] != NULL); |
| 372 | phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr; |
| 373 | assert(aux_info[AT_PHNUM] != NULL); |
| 374 | phnum = aux_info[AT_PHNUM]->a_un.a_val; |
| 375 | assert(aux_info[AT_PHENT] != NULL); |
| 376 | assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); |
| 377 | assert(aux_info[AT_ENTRY] != NULL); |
| 378 | entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr; |
| 379 | if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL) |
| 380 | die(); |
| 381 | } |
| 382 | |
| 383 | obj_main->path = xstrdup(argv0); |
| 384 | obj_main->mainprog = true; |
| 385 | |
| 386 | /* |
| 387 | * Get the actual dynamic linker pathname from the executable if |
| 388 | * possible. (It should always be possible.) That ensures that |
| 389 | * gdb will find the right dynamic linker even if a non-standard |
| 390 | * one is being used. |
| 391 | */ |
| 392 | if (obj_main->interp != NULL && |
| 393 | strcmp(obj_main->interp, obj_rtld.path) != 0) { |
| 394 | free(obj_rtld.path); |
| 395 | obj_rtld.path = xstrdup(obj_main->interp); |
| 396 | __progname = obj_rtld.path; |
| 397 | } |
| 398 | |
| 399 | digest_dynamic(obj_main); |
| 400 | |
| 401 | linkmap_add(obj_main); |
| 402 | linkmap_add(&obj_rtld); |
| 403 | |
| 404 | /* Link the main program into the list of objects. */ |
| 405 | *obj_tail = obj_main; |
| 406 | obj_tail = &obj_main->next; |
| 407 | obj_count++; |
| 408 | obj_main->refcount++; |
| 409 | /* Make sure we don't call the main program's init and fini functions. */ |
| 410 | obj_main->init = obj_main->fini = NULL; |
| 411 | |
| 412 | /* Initialize a fake symbol for resolving undefined weak references. */ |
| 413 | sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); |
| 414 | sym_zero.st_shndx = SHN_ABS; |
| 415 | |
| 416 | dbg("loading LD_PRELOAD libraries"); |
| 417 | if (load_preload_objects() == -1) |
| 418 | die(); |
| 419 | preload_tail = obj_tail; |
| 420 | |
| 421 | dbg("loading needed objects"); |
| 422 | if (load_needed_objects(obj_main) == -1) |
| 423 | die(); |
| 424 | |
| 425 | /* Make a list of all objects loaded at startup. */ |
| 426 | for (obj = obj_list; obj != NULL; obj = obj->next) |
| 427 | objlist_push_tail(&list_main, obj); |
| 428 | |
| 429 | resident_skip1: |
| 430 | |
| 431 | if (ld_tracing) { /* We're done */ |
| 432 | trace_loaded_objects(obj_main); |
| 433 | exit(0); |
| 434 | } |
| 435 | |
| 436 | if (ld_resident) /* XXX clean this up! */ |
| 437 | goto resident_skip2; |
| 438 | |
| 439 | if (getenv("LD_DUMP_REL_PRE") != NULL) { |
| 440 | dump_relocations(obj_main); |
| 441 | exit (0); |
| 442 | } |
| 443 | |
| 444 | /* setup TLS for main thread */ |
| 445 | dbg("initializing initial thread local storage"); |
| 446 | STAILQ_FOREACH(entry, &list_main, link) { |
| 447 | /* |
| 448 | * Allocate all the initial objects out of the static TLS |
| 449 | * block even if they didn't ask for it. |
| 450 | */ |
| 451 | allocate_tls_offset(entry->obj); |
| 452 | } |
| 453 | |
| 454 | tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; |
| 455 | |
| 456 | /* |
| 457 | * Do not try to allocate the TLS here, let libc do it itself. |
| 458 | * (crt1 for the program will call _init_tls()) |
| 459 | */ |
| 460 | |
| 461 | if (relocate_objects(obj_main, |
| 462 | ld_bind_now != NULL && *ld_bind_now != '\0') == -1) |
| 463 | die(); |
| 464 | |
| 465 | dbg("doing copy relocations"); |
| 466 | if (do_copy_relocations(obj_main) == -1) |
| 467 | die(); |
| 468 | |
| 469 | resident_skip2: |
| 470 | |
| 471 | if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) { |
| 472 | if (exec_sys_unregister(-1) < 0) { |
| 473 | dbg("exec_sys_unregister failed %d\n", errno); |
| 474 | exit(errno); |
| 475 | } |
| 476 | dbg("exec_sys_unregister success\n"); |
| 477 | exit(0); |
| 478 | } |
| 479 | |
| 480 | if (getenv("LD_DUMP_REL_POST") != NULL) { |
| 481 | dump_relocations(obj_main); |
| 482 | exit (0); |
| 483 | } |
| 484 | |
| 485 | dbg("initializing key program variables"); |
| 486 | set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); |
| 487 | set_program_var("environ", env); |
| 488 | |
| 489 | if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) { |
| 490 | extern void resident_start(void); |
| 491 | ld_resident = 1; |
| 492 | if (exec_sys_register(resident_start) < 0) { |
| 493 | dbg("exec_sys_register failed %d\n", errno); |
| 494 | exit(errno); |
| 495 | } |
| 496 | dbg("exec_sys_register success\n"); |
| 497 | exit(0); |
| 498 | } |
| 499 | |
| 500 | dbg("initializing thread locks"); |
| 501 | lockdflt_init(&lockinfo); |
| 502 | lockinfo.thelock = lockinfo.lock_create(lockinfo.context); |
| 503 | |
| 504 | /* Make a list of init functions to call. */ |
| 505 | objlist_init(&initlist); |
| 506 | initlist_add_objects(obj_list, preload_tail, &initlist); |
| 507 | |
| 508 | r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ |
| 509 | |
| 510 | /* |
| 511 | * Do NOT call the initlist here, give libc a chance to set up |
| 512 | * the initial TLS segment. crt1 will then call _rtld_call_init(). |
| 513 | */ |
| 514 | |
| 515 | dbg("transferring control to program entry point = %p", obj_main->entry); |
| 516 | |
| 517 | /* Return the exit procedure and the program entry point. */ |
| 518 | *exit_proc = rtld_exit; |
| 519 | *objp = obj_main; |
| 520 | return (func_ptr_type) obj_main->entry; |
| 521 | } |
| 522 | |
| 523 | /* |
| 524 | * Call the initialization list for dynamically loaded libraries. |
| 525 | * (called from crt1.c). |
| 526 | */ |
| 527 | void |
| 528 | _rtld_call_init(void) |
| 529 | { |
| 530 | objlist_call_init(&initlist); |
| 531 | wlock_acquire(); |
| 532 | objlist_clear(&initlist); |
| 533 | wlock_release(); |
| 534 | } |
| 535 | |
| 536 | Elf_Addr |
| 537 | _rtld_bind(Obj_Entry *obj, Elf_Word reloff) |
| 538 | { |
| 539 | const Elf_Rel *rel; |
| 540 | const Elf_Sym *def; |
| 541 | const Obj_Entry *defobj; |
| 542 | Elf_Addr *where; |
| 543 | Elf_Addr target; |
| 544 | |
| 545 | rlock_acquire(); |
| 546 | if (obj->pltrel) |
| 547 | rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff); |
| 548 | else |
| 549 | rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff); |
| 550 | |
| 551 | where = (Elf_Addr *) (obj->relocbase + rel->r_offset); |
| 552 | def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL); |
| 553 | if (def == NULL) |
| 554 | die(); |
| 555 | |
| 556 | target = (Elf_Addr)(defobj->relocbase + def->st_value); |
| 557 | |
| 558 | dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", |
| 559 | defobj->strtab + def->st_name, basename(obj->path), |
| 560 | (void *)target, basename(defobj->path)); |
| 561 | |
| 562 | reloc_jmpslot(where, target); |
| 563 | rlock_release(); |
| 564 | return target; |
| 565 | } |
| 566 | |
| 567 | /* |
| 568 | * Error reporting function. Use it like printf. If formats the message |
| 569 | * into a buffer, and sets things up so that the next call to dlerror() |
| 570 | * will return the message. |
| 571 | */ |
| 572 | void |
| 573 | _rtld_error(const char *fmt, ...) |
| 574 | { |
| 575 | static char buf[512]; |
| 576 | va_list ap; |
| 577 | |
| 578 | va_start(ap, fmt); |
| 579 | vsnprintf(buf, sizeof buf, fmt, ap); |
| 580 | error_message = buf; |
| 581 | va_end(ap); |
| 582 | } |
| 583 | |
| 584 | /* |
| 585 | * Return a dynamically-allocated copy of the current error message, if any. |
| 586 | */ |
| 587 | static char * |
| 588 | errmsg_save(void) |
| 589 | { |
| 590 | return error_message == NULL ? NULL : xstrdup(error_message); |
| 591 | } |
| 592 | |
| 593 | /* |
| 594 | * Restore the current error message from a copy which was previously saved |
| 595 | * by errmsg_save(). The copy is freed. |
| 596 | */ |
| 597 | static void |
| 598 | errmsg_restore(char *saved_msg) |
| 599 | { |
| 600 | if (saved_msg == NULL) |
| 601 | error_message = NULL; |
| 602 | else { |
| 603 | _rtld_error("%s", saved_msg); |
| 604 | free(saved_msg); |
| 605 | } |
| 606 | } |
| 607 | |
| 608 | const char * |
| 609 | basename(const char *name) |
| 610 | { |
| 611 | const char *p = strrchr(name, '/'); |
| 612 | return p != NULL ? p + 1 : name; |
| 613 | } |
| 614 | |
| 615 | static void |
| 616 | die(void) |
| 617 | { |
| 618 | const char *msg = dlerror(); |
| 619 | |
| 620 | if (msg == NULL) |
| 621 | msg = "Fatal error"; |
| 622 | errx(1, "%s", msg); |
| 623 | } |
| 624 | |
| 625 | /* |
| 626 | * Process a shared object's DYNAMIC section, and save the important |
| 627 | * information in its Obj_Entry structure. |
| 628 | */ |
| 629 | static void |
| 630 | digest_dynamic(Obj_Entry *obj) |
| 631 | { |
| 632 | const Elf_Dyn *dynp; |
| 633 | Needed_Entry **needed_tail = &obj->needed; |
| 634 | const Elf_Dyn *dyn_rpath = NULL; |
| 635 | int plttype = DT_REL; |
| 636 | |
| 637 | for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) { |
| 638 | switch (dynp->d_tag) { |
| 639 | |
| 640 | case DT_REL: |
| 641 | obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr); |
| 642 | break; |
| 643 | |
| 644 | case DT_RELSZ: |
| 645 | obj->relsize = dynp->d_un.d_val; |
| 646 | break; |
| 647 | |
| 648 | case DT_RELENT: |
| 649 | assert(dynp->d_un.d_val == sizeof(Elf_Rel)); |
| 650 | break; |
| 651 | |
| 652 | case DT_JMPREL: |
| 653 | obj->pltrel = (const Elf_Rel *) |
| 654 | (obj->relocbase + dynp->d_un.d_ptr); |
| 655 | break; |
| 656 | |
| 657 | case DT_PLTRELSZ: |
| 658 | obj->pltrelsize = dynp->d_un.d_val; |
| 659 | break; |
| 660 | |
| 661 | case DT_RELA: |
| 662 | obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr); |
| 663 | break; |
| 664 | |
| 665 | case DT_RELASZ: |
| 666 | obj->relasize = dynp->d_un.d_val; |
| 667 | break; |
| 668 | |
| 669 | case DT_RELAENT: |
| 670 | assert(dynp->d_un.d_val == sizeof(Elf_Rela)); |
| 671 | break; |
| 672 | |
| 673 | case DT_PLTREL: |
| 674 | plttype = dynp->d_un.d_val; |
| 675 | assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA); |
| 676 | break; |
| 677 | |
| 678 | case DT_SYMTAB: |
| 679 | obj->symtab = (const Elf_Sym *) |
| 680 | (obj->relocbase + dynp->d_un.d_ptr); |
| 681 | break; |
| 682 | |
| 683 | case DT_SYMENT: |
| 684 | assert(dynp->d_un.d_val == sizeof(Elf_Sym)); |
| 685 | break; |
| 686 | |
| 687 | case DT_STRTAB: |
| 688 | obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr); |
| 689 | break; |
| 690 | |
| 691 | case DT_STRSZ: |
| 692 | obj->strsize = dynp->d_un.d_val; |
| 693 | break; |
| 694 | |
| 695 | case DT_HASH: |
| 696 | { |
| 697 | const Elf_Addr *hashtab = (const Elf_Addr *) |
| 698 | (obj->relocbase + dynp->d_un.d_ptr); |
| 699 | obj->nbuckets = hashtab[0]; |
| 700 | obj->nchains = hashtab[1]; |
| 701 | obj->buckets = hashtab + 2; |
| 702 | obj->chains = obj->buckets + obj->nbuckets; |
| 703 | } |
| 704 | break; |
| 705 | |
| 706 | case DT_NEEDED: |
| 707 | if (!obj->rtld) { |
| 708 | Needed_Entry *nep = NEW(Needed_Entry); |
| 709 | nep->name = dynp->d_un.d_val; |
| 710 | nep->obj = NULL; |
| 711 | nep->next = NULL; |
| 712 | |
| 713 | *needed_tail = nep; |
| 714 | needed_tail = &nep->next; |
| 715 | } |
| 716 | break; |
| 717 | |
| 718 | case DT_PLTGOT: |
| 719 | obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr); |
| 720 | break; |
| 721 | |
| 722 | case DT_TEXTREL: |
| 723 | obj->textrel = true; |
| 724 | break; |
| 725 | |
| 726 | case DT_SYMBOLIC: |
| 727 | obj->symbolic = true; |
| 728 | break; |
| 729 | |
| 730 | case DT_RPATH: |
| 731 | case DT_RUNPATH: /* XXX: process separately */ |
| 732 | /* |
| 733 | * We have to wait until later to process this, because we |
| 734 | * might not have gotten the address of the string table yet. |
| 735 | */ |
| 736 | dyn_rpath = dynp; |
| 737 | break; |
| 738 | |
| 739 | case DT_SONAME: |
| 740 | /* Not used by the dynamic linker. */ |
| 741 | break; |
| 742 | |
| 743 | case DT_INIT: |
| 744 | obj->init = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr); |
| 745 | break; |
| 746 | |
| 747 | case DT_FINI: |
| 748 | obj->fini = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr); |
| 749 | break; |
| 750 | |
| 751 | case DT_DEBUG: |
| 752 | /* XXX - not implemented yet */ |
| 753 | dbg("Filling in DT_DEBUG entry"); |
| 754 | ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug; |
| 755 | break; |
| 756 | |
| 757 | case DT_FLAGS: |
| 758 | if (dynp->d_un.d_val & DF_ORIGIN) { |
| 759 | obj->origin_path = xmalloc(PATH_MAX); |
| 760 | if (rtld_dirname(obj->path, obj->origin_path) == -1) |
| 761 | die(); |
| 762 | } |
| 763 | if (dynp->d_un.d_val & DF_SYMBOLIC) |
| 764 | obj->symbolic = true; |
| 765 | if (dynp->d_un.d_val & DF_TEXTREL) |
| 766 | obj->textrel = true; |
| 767 | if (dynp->d_un.d_val & DF_BIND_NOW) |
| 768 | obj->bind_now = true; |
| 769 | if (dynp->d_un.d_val & DF_STATIC_TLS) |
| 770 | ; |
| 771 | break; |
| 772 | |
| 773 | default: |
| 774 | dbg("Ignoring d_tag %d = %#x", dynp->d_tag, dynp->d_tag); |
| 775 | break; |
| 776 | } |
| 777 | } |
| 778 | |
| 779 | obj->traced = false; |
| 780 | |
| 781 | if (plttype == DT_RELA) { |
| 782 | obj->pltrela = (const Elf_Rela *) obj->pltrel; |
| 783 | obj->pltrel = NULL; |
| 784 | obj->pltrelasize = obj->pltrelsize; |
| 785 | obj->pltrelsize = 0; |
| 786 | } |
| 787 | |
| 788 | if (dyn_rpath != NULL) |
| 789 | obj->rpath = obj->strtab + dyn_rpath->d_un.d_val; |
| 790 | } |
| 791 | |
| 792 | /* |
| 793 | * Process a shared object's program header. This is used only for the |
| 794 | * main program, when the kernel has already loaded the main program |
| 795 | * into memory before calling the dynamic linker. It creates and |
| 796 | * returns an Obj_Entry structure. |
| 797 | */ |
| 798 | static Obj_Entry * |
| 799 | digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) |
| 800 | { |
| 801 | Obj_Entry *obj; |
| 802 | const Elf_Phdr *phlimit = phdr + phnum; |
| 803 | const Elf_Phdr *ph; |
| 804 | int nsegs = 0; |
| 805 | |
| 806 | obj = obj_new(); |
| 807 | for (ph = phdr; ph < phlimit; ph++) { |
| 808 | switch (ph->p_type) { |
| 809 | |
| 810 | case PT_PHDR: |
| 811 | if ((const Elf_Phdr *)ph->p_vaddr != phdr) { |
| 812 | _rtld_error("%s: invalid PT_PHDR", path); |
| 813 | return NULL; |
| 814 | } |
| 815 | obj->phdr = (const Elf_Phdr *) ph->p_vaddr; |
| 816 | obj->phsize = ph->p_memsz; |
| 817 | break; |
| 818 | |
| 819 | case PT_INTERP: |
| 820 | obj->interp = (const char *) ph->p_vaddr; |
| 821 | break; |
| 822 | |
| 823 | case PT_LOAD: |
| 824 | if (nsegs == 0) { /* First load segment */ |
| 825 | obj->vaddrbase = trunc_page(ph->p_vaddr); |
| 826 | obj->mapbase = (caddr_t) obj->vaddrbase; |
| 827 | obj->relocbase = obj->mapbase - obj->vaddrbase; |
| 828 | obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - |
| 829 | obj->vaddrbase; |
| 830 | } else { /* Last load segment */ |
| 831 | obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - |
| 832 | obj->vaddrbase; |
| 833 | } |
| 834 | nsegs++; |
| 835 | break; |
| 836 | |
| 837 | case PT_DYNAMIC: |
| 838 | obj->dynamic = (const Elf_Dyn *) ph->p_vaddr; |
| 839 | break; |
| 840 | |
| 841 | case PT_TLS: |
| 842 | obj->tlsindex = 1; |
| 843 | obj->tlssize = ph->p_memsz; |
| 844 | obj->tlsalign = ph->p_align; |
| 845 | obj->tlsinitsize = ph->p_filesz; |
| 846 | obj->tlsinit = (void*) ph->p_vaddr; |
| 847 | break; |
| 848 | } |
| 849 | } |
| 850 | if (nsegs < 1) { |
| 851 | _rtld_error("%s: too few PT_LOAD segments", path); |
| 852 | return NULL; |
| 853 | } |
| 854 | |
| 855 | obj->entry = entry; |
| 856 | return obj; |
| 857 | } |
| 858 | |
| 859 | static Obj_Entry * |
| 860 | dlcheck(void *handle) |
| 861 | { |
| 862 | Obj_Entry *obj; |
| 863 | |
| 864 | for (obj = obj_list; obj != NULL; obj = obj->next) |
| 865 | if (obj == (Obj_Entry *) handle) |
| 866 | break; |
| 867 | |
| 868 | if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { |
| 869 | _rtld_error("Invalid shared object handle %p", handle); |
| 870 | return NULL; |
| 871 | } |
| 872 | return obj; |
| 873 | } |
| 874 | |
| 875 | /* |
| 876 | * If the given object is already in the donelist, return true. Otherwise |
| 877 | * add the object to the list and return false. |
| 878 | */ |
| 879 | static bool |
| 880 | donelist_check(DoneList *dlp, const Obj_Entry *obj) |
| 881 | { |
| 882 | unsigned int i; |
| 883 | |
| 884 | for (i = 0; i < dlp->num_used; i++) |
| 885 | if (dlp->objs[i] == obj) |
| 886 | return true; |
| 887 | /* |
| 888 | * Our donelist allocation should always be sufficient. But if |
| 889 | * our threads locking isn't working properly, more shared objects |
| 890 | * could have been loaded since we allocated the list. That should |
| 891 | * never happen, but we'll handle it properly just in case it does. |
| 892 | */ |
| 893 | if (dlp->num_used < dlp->num_alloc) |
| 894 | dlp->objs[dlp->num_used++] = obj; |
| 895 | return false; |
| 896 | } |
| 897 | |
| 898 | /* |
| 899 | * Hash function for symbol table lookup. Don't even think about changing |
| 900 | * this. It is specified by the System V ABI. |
| 901 | */ |
| 902 | unsigned long |
| 903 | elf_hash(const char *name) |
| 904 | { |
| 905 | const unsigned char *p = (const unsigned char *) name; |
| 906 | unsigned long h = 0; |
| 907 | unsigned long g; |
| 908 | |
| 909 | while (*p != '\0') { |
| 910 | h = (h << 4) + *p++; |
| 911 | if ((g = h & 0xf0000000) != 0) |
| 912 | h ^= g >> 24; |
| 913 | h &= ~g; |
| 914 | } |
| 915 | return h; |
| 916 | } |
| 917 | |
| 918 | /* |
| 919 | * Find the library with the given name, and return its full pathname. |
| 920 | * The returned string is dynamically allocated. Generates an error |
| 921 | * message and returns NULL if the library cannot be found. |
| 922 | * |
| 923 | * If the second argument is non-NULL, then it refers to an already- |
| 924 | * loaded shared object, whose library search path will be searched. |
| 925 | * |
| 926 | * The search order is: |
| 927 | * LD_LIBRARY_PATH |
| 928 | * rpath in the referencing file |
| 929 | * ldconfig hints |
| 930 | * /usr/lib |
| 931 | */ |
| 932 | static char * |
| 933 | find_library(const char *name, const Obj_Entry *refobj) |
| 934 | { |
| 935 | char *pathname; |
| 936 | |
| 937 | if (strchr(name, '/') != NULL) { /* Hard coded pathname */ |
| 938 | if (name[0] != '/' && !trust) { |
| 939 | _rtld_error("Absolute pathname required for shared object \"%s\"", |
| 940 | name); |
| 941 | return NULL; |
| 942 | } |
| 943 | return xstrdup(name); |
| 944 | } |
| 945 | |
| 946 | dbg(" Searching for \"%s\"", name); |
| 947 | |
| 948 | if ((pathname = search_library_path(name, ld_library_path)) != NULL || |
| 949 | (refobj != NULL && |
| 950 | (pathname = search_library_path(name, refobj->rpath)) != NULL) || |
| 951 | (pathname = search_library_path(name, gethints())) != NULL || |
| 952 | (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL) |
| 953 | return pathname; |
| 954 | |
| 955 | if(refobj != NULL && refobj->path != NULL) { |
| 956 | _rtld_error("Shared object \"%s\" not found, required by \"%s\"", |
| 957 | name, basename(refobj->path)); |
| 958 | } else { |
| 959 | _rtld_error("Shared object \"%s\" not found", name); |
| 960 | } |
| 961 | return NULL; |
| 962 | } |
| 963 | |
| 964 | /* |
| 965 | * Given a symbol number in a referencing object, find the corresponding |
| 966 | * definition of the symbol. Returns a pointer to the symbol, or NULL if |
| 967 | * no definition was found. Returns a pointer to the Obj_Entry of the |
| 968 | * defining object via the reference parameter DEFOBJ_OUT. |
| 969 | */ |
| 970 | const Elf_Sym * |
| 971 | find_symdef(unsigned long symnum, const Obj_Entry *refobj, |
| 972 | const Obj_Entry **defobj_out, bool in_plt, SymCache *cache) |
| 973 | { |
| 974 | const Elf_Sym *ref; |
| 975 | const Elf_Sym *def; |
| 976 | const Obj_Entry *defobj; |
| 977 | const char *name; |
| 978 | unsigned long hash; |
| 979 | |
| 980 | /* |
| 981 | * If we have already found this symbol, get the information from |
| 982 | * the cache. |
| 983 | */ |
| 984 | if (symnum >= refobj->nchains) |
| 985 | return NULL; /* Bad object */ |
| 986 | if (cache != NULL && cache[symnum].sym != NULL) { |
| 987 | *defobj_out = cache[symnum].obj; |
| 988 | return cache[symnum].sym; |
| 989 | } |
| 990 | |
| 991 | ref = refobj->symtab + symnum; |
| 992 | name = refobj->strtab + ref->st_name; |
| 993 | hash = elf_hash(name); |
| 994 | defobj = NULL; |
| 995 | |
| 996 | def = symlook_default(name, hash, refobj, &defobj, in_plt); |
| 997 | |
| 998 | /* |
| 999 | * If we found no definition and the reference is weak, treat the |
| 1000 | * symbol as having the value zero. |
| 1001 | */ |
| 1002 | if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { |
| 1003 | def = &sym_zero; |
| 1004 | defobj = obj_main; |
| 1005 | } |
| 1006 | |
| 1007 | if (def != NULL) { |
| 1008 | *defobj_out = defobj; |
| 1009 | /* Record the information in the cache to avoid subsequent lookups. */ |
| 1010 | if (cache != NULL) { |
| 1011 | cache[symnum].sym = def; |
| 1012 | cache[symnum].obj = defobj; |
| 1013 | } |
| 1014 | } else |
| 1015 | _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name); |
| 1016 | return def; |
| 1017 | } |
| 1018 | |
| 1019 | /* |
| 1020 | * Return the search path from the ldconfig hints file, reading it if |
| 1021 | * necessary. Returns NULL if there are problems with the hints file, |
| 1022 | * or if the search path there is empty. |
| 1023 | */ |
| 1024 | static const char * |
| 1025 | gethints(void) |
| 1026 | { |
| 1027 | static char *hints; |
| 1028 | |
| 1029 | if (hints == NULL) { |
| 1030 | int fd; |
| 1031 | struct elfhints_hdr hdr; |
| 1032 | char *p; |
| 1033 | |
| 1034 | /* Keep from trying again in case the hints file is bad. */ |
| 1035 | hints = ""; |
| 1036 | |
| 1037 | if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1) |
| 1038 | return NULL; |
| 1039 | if (read(fd, &hdr, sizeof hdr) != sizeof hdr || |
| 1040 | hdr.magic != ELFHINTS_MAGIC || |
| 1041 | hdr.version != 1) { |
| 1042 | close(fd); |
| 1043 | return NULL; |
| 1044 | } |
| 1045 | p = xmalloc(hdr.dirlistlen + 1); |
| 1046 | if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 || |
| 1047 | read(fd, p, hdr.dirlistlen + 1) != hdr.dirlistlen + 1) { |
| 1048 | free(p); |
| 1049 | close(fd); |
| 1050 | return NULL; |
| 1051 | } |
| 1052 | hints = p; |
| 1053 | close(fd); |
| 1054 | } |
| 1055 | return hints[0] != '\0' ? hints : NULL; |
| 1056 | } |
| 1057 | |
| 1058 | static void |
| 1059 | init_dag(Obj_Entry *root) |
| 1060 | { |
| 1061 | DoneList donelist; |
| 1062 | |
| 1063 | donelist_init(&donelist); |
| 1064 | init_dag1(root, root, &donelist); |
| 1065 | } |
| 1066 | |
| 1067 | static void |
| 1068 | init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp) |
| 1069 | { |
| 1070 | const Needed_Entry *needed; |
| 1071 | |
| 1072 | if (donelist_check(dlp, obj)) |
| 1073 | return; |
| 1074 | objlist_push_tail(&obj->dldags, root); |
| 1075 | objlist_push_tail(&root->dagmembers, obj); |
| 1076 | for (needed = obj->needed; needed != NULL; needed = needed->next) |
| 1077 | if (needed->obj != NULL) |
| 1078 | init_dag1(root, needed->obj, dlp); |
| 1079 | } |
| 1080 | |
| 1081 | /* |
| 1082 | * Initialize the dynamic linker. The argument is the address at which |
| 1083 | * the dynamic linker has been mapped into memory. The primary task of |
| 1084 | * this function is to relocate the dynamic linker. |
| 1085 | */ |
| 1086 | static void |
| 1087 | init_rtld(caddr_t mapbase) |
| 1088 | { |
| 1089 | /* |
| 1090 | * Conjure up an Obj_Entry structure for the dynamic linker. |
| 1091 | * |
| 1092 | * The "path" member is supposed to be dynamically-allocated, but we |
| 1093 | * aren't yet initialized sufficiently to do that. Below we will |
| 1094 | * replace the static version with a dynamically-allocated copy. |
| 1095 | */ |
| 1096 | obj_rtld.path = PATH_RTLD; |
| 1097 | obj_rtld.rtld = true; |
| 1098 | obj_rtld.mapbase = mapbase; |
| 1099 | #ifdef PIC |
| 1100 | obj_rtld.relocbase = mapbase; |
| 1101 | #endif |
| 1102 | if (&_DYNAMIC != 0) { |
| 1103 | obj_rtld.dynamic = rtld_dynamic(&obj_rtld); |
| 1104 | digest_dynamic(&obj_rtld); |
| 1105 | assert(obj_rtld.needed == NULL); |
| 1106 | assert(!obj_rtld.textrel); |
| 1107 | |
| 1108 | /* |
| 1109 | * Temporarily put the dynamic linker entry into the object list, so |
| 1110 | * that symbols can be found. |
| 1111 | */ |
| 1112 | obj_list = &obj_rtld; |
| 1113 | obj_tail = &obj_rtld.next; |
| 1114 | obj_count = 1; |
| 1115 | |
| 1116 | relocate_objects(&obj_rtld, true); |
| 1117 | } |
| 1118 | |
| 1119 | /* Make the object list empty again. */ |
| 1120 | obj_list = NULL; |
| 1121 | obj_tail = &obj_list; |
| 1122 | obj_count = 0; |
| 1123 | |
| 1124 | /* Replace the path with a dynamically allocated copy. */ |
| 1125 | obj_rtld.path = xstrdup(obj_rtld.path); |
| 1126 | |
| 1127 | r_debug.r_brk = r_debug_state; |
| 1128 | r_debug.r_state = RT_CONSISTENT; |
| 1129 | } |
| 1130 | |
| 1131 | /* |
| 1132 | * Add the init functions from a needed object list (and its recursive |
| 1133 | * needed objects) to "list". This is not used directly; it is a helper |
| 1134 | * function for initlist_add_objects(). The write lock must be held |
| 1135 | * when this function is called. |
| 1136 | */ |
| 1137 | static void |
| 1138 | initlist_add_neededs(Needed_Entry *needed, Objlist *list) |
| 1139 | { |
| 1140 | /* Recursively process the successor needed objects. */ |
| 1141 | if (needed->next != NULL) |
| 1142 | initlist_add_neededs(needed->next, list); |
| 1143 | |
| 1144 | /* Process the current needed object. */ |
| 1145 | if (needed->obj != NULL) |
| 1146 | initlist_add_objects(needed->obj, &needed->obj->next, list); |
| 1147 | } |
| 1148 | |
| 1149 | /* |
| 1150 | * Scan all of the DAGs rooted in the range of objects from "obj" to |
| 1151 | * "tail" and add their init functions to "list". This recurses over |
| 1152 | * the DAGs and ensure the proper init ordering such that each object's |
| 1153 | * needed libraries are initialized before the object itself. At the |
| 1154 | * same time, this function adds the objects to the global finalization |
| 1155 | * list "list_fini" in the opposite order. The write lock must be |
| 1156 | * held when this function is called. |
| 1157 | */ |
| 1158 | static void |
| 1159 | initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list) |
| 1160 | { |
| 1161 | if (obj->init_done) |
| 1162 | return; |
| 1163 | obj->init_done = true; |
| 1164 | |
| 1165 | /* Recursively process the successor objects. */ |
| 1166 | if (&obj->next != tail) |
| 1167 | initlist_add_objects(obj->next, tail, list); |
| 1168 | |
| 1169 | /* Recursively process the needed objects. */ |
| 1170 | if (obj->needed != NULL) |
| 1171 | initlist_add_neededs(obj->needed, list); |
| 1172 | |
| 1173 | /* Add the object to the init list. */ |
| 1174 | if (obj->init != NULL) |
| 1175 | objlist_push_tail(list, obj); |
| 1176 | |
| 1177 | /* Add the object to the global fini list in the reverse order. */ |
| 1178 | if (obj->fini != NULL) |
| 1179 | objlist_push_head(&list_fini, obj); |
| 1180 | } |
| 1181 | |
| 1182 | static bool |
| 1183 | is_exported(const Elf_Sym *def) |
| 1184 | { |
| 1185 | func_ptr_type value; |
| 1186 | const func_ptr_type *p; |
| 1187 | |
| 1188 | value = (func_ptr_type)(obj_rtld.relocbase + def->st_value); |
| 1189 | for (p = exports; *p != NULL; p++) |
| 1190 | if (*p == value) |
| 1191 | return true; |
| 1192 | return false; |
| 1193 | } |
| 1194 | |
| 1195 | /* |
| 1196 | * Given a shared object, traverse its list of needed objects, and load |
| 1197 | * each of them. Returns 0 on success. Generates an error message and |
| 1198 | * returns -1 on failure. |
| 1199 | */ |
| 1200 | static int |
| 1201 | load_needed_objects(Obj_Entry *first) |
| 1202 | { |
| 1203 | Obj_Entry *obj; |
| 1204 | |
| 1205 | for (obj = first; obj != NULL; obj = obj->next) { |
| 1206 | Needed_Entry *needed; |
| 1207 | |
| 1208 | for (needed = obj->needed; needed != NULL; needed = needed->next) { |
| 1209 | const char *name = obj->strtab + needed->name; |
| 1210 | char *path = find_library(name, obj); |
| 1211 | |
| 1212 | needed->obj = NULL; |
| 1213 | if (path == NULL && !ld_tracing) |
| 1214 | return -1; |
| 1215 | |
| 1216 | if (path) { |
| 1217 | needed->obj = load_object(path); |
| 1218 | if (needed->obj == NULL && !ld_tracing) |
| 1219 | return -1; /* XXX - cleanup */ |
| 1220 | } |
| 1221 | } |
| 1222 | } |
| 1223 | |
| 1224 | return 0; |
| 1225 | } |
| 1226 | |
| 1227 | static int |
| 1228 | load_preload_objects(void) |
| 1229 | { |
| 1230 | char *p = ld_preload; |
| 1231 | static const char delim[] = " \t:;"; |
| 1232 | |
| 1233 | if (p == NULL) |
| 1234 | return NULL; |
| 1235 | |
| 1236 | p += strspn(p, delim); |
| 1237 | while (*p != '\0') { |
| 1238 | size_t len = strcspn(p, delim); |
| 1239 | char *path; |
| 1240 | char savech; |
| 1241 | |
| 1242 | savech = p[len]; |
| 1243 | p[len] = '\0'; |
| 1244 | if ((path = find_library(p, NULL)) == NULL) |
| 1245 | return -1; |
| 1246 | if (load_object(path) == NULL) |
| 1247 | return -1; /* XXX - cleanup */ |
| 1248 | p[len] = savech; |
| 1249 | p += len; |
| 1250 | p += strspn(p, delim); |
| 1251 | } |
| 1252 | return 0; |
| 1253 | } |
| 1254 | |
| 1255 | /* |
| 1256 | * Returns a pointer to the Obj_Entry for the object with the given path. |
| 1257 | * Returns NULL if no matching object was found. |
| 1258 | */ |
| 1259 | static Obj_Entry * |
| 1260 | find_object(const char *path) |
| 1261 | { |
| 1262 | Obj_Entry *obj; |
| 1263 | |
| 1264 | for (obj = obj_list->next; obj != NULL; obj = obj->next) { |
| 1265 | if (strcmp(obj->path, path) == 0) |
| 1266 | return(obj); |
| 1267 | } |
| 1268 | return(NULL); |
| 1269 | } |
| 1270 | |
| 1271 | /* |
| 1272 | * Returns a pointer to the Obj_Entry for the object matching device and |
| 1273 | * inode of the given path. If no matching object was found, the descriptor |
| 1274 | * is returned in fd. |
| 1275 | * Returns with obj == NULL && fd == -1 on error. |
| 1276 | */ |
| 1277 | static Obj_Entry * |
| 1278 | find_object2(const char *path, int *fd, struct stat *sb) |
| 1279 | { |
| 1280 | Obj_Entry *obj; |
| 1281 | |
| 1282 | if ((*fd = open(path, O_RDONLY)) == -1) { |
| 1283 | _rtld_error("Cannot open \"%s\"", path); |
| 1284 | return(NULL); |
| 1285 | } |
| 1286 | |
| 1287 | if (fstat(*fd, sb) == -1) { |
| 1288 | _rtld_error("Cannot fstat \"%s\"", path); |
| 1289 | close(*fd); |
| 1290 | *fd = -1; |
| 1291 | return NULL; |
| 1292 | } |
| 1293 | |
| 1294 | for (obj = obj_list->next; obj != NULL; obj = obj->next) { |
| 1295 | if (obj->ino == sb->st_ino && obj->dev == sb->st_dev) { |
| 1296 | close(*fd); |
| 1297 | break; |
| 1298 | } |
| 1299 | } |
| 1300 | |
| 1301 | return(obj); |
| 1302 | } |
| 1303 | |
| 1304 | /* |
| 1305 | * Load a shared object into memory, if it is not already loaded. The |
| 1306 | * argument must be a string allocated on the heap. This function assumes |
| 1307 | * responsibility for freeing it when necessary. |
| 1308 | * |
| 1309 | * Returns a pointer to the Obj_Entry for the object. Returns NULL |
| 1310 | * on failure. |
| 1311 | */ |
| 1312 | static Obj_Entry * |
| 1313 | load_object(char *path) |
| 1314 | { |
| 1315 | Obj_Entry *obj; |
| 1316 | int fd = -1; |
| 1317 | struct stat sb; |
| 1318 | |
| 1319 | obj = find_object(path); |
| 1320 | if (obj != NULL) { |
| 1321 | obj->refcount++; |
| 1322 | free(path); |
| 1323 | return(obj); |
| 1324 | } |
| 1325 | |
| 1326 | obj = find_object2(path, &fd, &sb); |
| 1327 | if (obj != NULL) { |
| 1328 | obj->refcount++; |
| 1329 | free(path); |
| 1330 | return(obj); |
| 1331 | } else if (fd == -1) { |
| 1332 | free(path); |
| 1333 | return(NULL); |
| 1334 | } |
| 1335 | |
| 1336 | dbg("loading \"%s\"", path); |
| 1337 | obj = map_object(fd, path, &sb); |
| 1338 | close(fd); |
| 1339 | if (obj == NULL) { |
| 1340 | free(path); |
| 1341 | return NULL; |
| 1342 | } |
| 1343 | |
| 1344 | obj->path = path; |
| 1345 | digest_dynamic(obj); |
| 1346 | |
| 1347 | *obj_tail = obj; |
| 1348 | obj_tail = &obj->next; |
| 1349 | obj_count++; |
| 1350 | linkmap_add(obj); /* for GDB & dlinfo() */ |
| 1351 | |
| 1352 | dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1, |
| 1353 | obj->path); |
| 1354 | if (obj->textrel) |
| 1355 | dbg(" WARNING: %s has impure text", obj->path); |
| 1356 | |
| 1357 | obj->refcount++; |
| 1358 | return obj; |
| 1359 | } |
| 1360 | |
| 1361 | /* |
| 1362 | * Check for locking violations and die if one is found. |
| 1363 | */ |
| 1364 | static void |
| 1365 | lock_check(void) |
| 1366 | { |
| 1367 | int rcount, wcount; |
| 1368 | |
| 1369 | rcount = lockinfo.rcount; |
| 1370 | wcount = lockinfo.wcount; |
| 1371 | assert(rcount >= 0); |
| 1372 | assert(wcount >= 0); |
| 1373 | if (wcount > 1 || (wcount != 0 && rcount != 0)) { |
| 1374 | _rtld_error("Application locking error: %d readers and %d writers" |
| 1375 | " in dynamic linker. See DLLOCKINIT(3) in manual pages.", |
| 1376 | rcount, wcount); |
| 1377 | die(); |
| 1378 | } |
| 1379 | } |
| 1380 | |
| 1381 | static Obj_Entry * |
| 1382 | obj_from_addr(const void *addr) |
| 1383 | { |
| 1384 | Obj_Entry *obj; |
| 1385 | |
| 1386 | for (obj = obj_list; obj != NULL; obj = obj->next) { |
| 1387 | if (addr < (void *) obj->mapbase) |
| 1388 | continue; |
| 1389 | if (addr < (void *) (obj->mapbase + obj->mapsize)) |
| 1390 | return obj; |
| 1391 | } |
| 1392 | return NULL; |
| 1393 | } |
| 1394 | |
| 1395 | /* |
| 1396 | * Call the finalization functions for each of the objects in "list" |
| 1397 | * which are unreferenced. All of the objects are expected to have |
| 1398 | * non-NULL fini functions. |
| 1399 | */ |
| 1400 | static void |
| 1401 | objlist_call_fini(Objlist *list) |
| 1402 | { |
| 1403 | Objlist_Entry *elm; |
| 1404 | char *saved_msg; |
| 1405 | |
| 1406 | /* |
| 1407 | * Preserve the current error message since a fini function might |
| 1408 | * call into the dynamic linker and overwrite it. |
| 1409 | */ |
| 1410 | saved_msg = errmsg_save(); |
| 1411 | STAILQ_FOREACH(elm, list, link) { |
| 1412 | if (elm->obj->refcount == 0) { |
| 1413 | dbg("calling fini function for %s", elm->obj->path); |
| 1414 | (*elm->obj->fini)(); |
| 1415 | } |
| 1416 | } |
| 1417 | errmsg_restore(saved_msg); |
| 1418 | } |
| 1419 | |
| 1420 | /* |
| 1421 | * Call the initialization functions for each of the objects in |
| 1422 | * "list". All of the objects are expected to have non-NULL init |
| 1423 | * functions. |
| 1424 | */ |
| 1425 | static void |
| 1426 | objlist_call_init(Objlist *list) |
| 1427 | { |
| 1428 | Objlist_Entry *elm; |
| 1429 | char *saved_msg; |
| 1430 | |
| 1431 | /* |
| 1432 | * Preserve the current error message since an init function might |
| 1433 | * call into the dynamic linker and overwrite it. |
| 1434 | */ |
| 1435 | saved_msg = errmsg_save(); |
| 1436 | STAILQ_FOREACH(elm, list, link) { |
| 1437 | dbg("calling init function for %s", elm->obj->path); |
| 1438 | (*elm->obj->init)(); |
| 1439 | } |
| 1440 | errmsg_restore(saved_msg); |
| 1441 | } |
| 1442 | |
| 1443 | static void |
| 1444 | objlist_clear(Objlist *list) |
| 1445 | { |
| 1446 | Objlist_Entry *elm; |
| 1447 | |
| 1448 | while (!STAILQ_EMPTY(list)) { |
| 1449 | elm = STAILQ_FIRST(list); |
| 1450 | STAILQ_REMOVE_HEAD(list, link); |
| 1451 | free(elm); |
| 1452 | } |
| 1453 | } |
| 1454 | |
| 1455 | static Objlist_Entry * |
| 1456 | objlist_find(Objlist *list, const Obj_Entry *obj) |
| 1457 | { |
| 1458 | Objlist_Entry *elm; |
| 1459 | |
| 1460 | STAILQ_FOREACH(elm, list, link) |
| 1461 | if (elm->obj == obj) |
| 1462 | return elm; |
| 1463 | return NULL; |
| 1464 | } |
| 1465 | |
| 1466 | static void |
| 1467 | objlist_init(Objlist *list) |
| 1468 | { |
| 1469 | STAILQ_INIT(list); |
| 1470 | } |
| 1471 | |
| 1472 | static void |
| 1473 | objlist_push_head(Objlist *list, Obj_Entry *obj) |
| 1474 | { |
| 1475 | Objlist_Entry *elm; |
| 1476 | |
| 1477 | elm = NEW(Objlist_Entry); |
| 1478 | elm->obj = obj; |
| 1479 | STAILQ_INSERT_HEAD(list, elm, link); |
| 1480 | } |
| 1481 | |
| 1482 | static void |
| 1483 | objlist_push_tail(Objlist *list, Obj_Entry *obj) |
| 1484 | { |
| 1485 | Objlist_Entry *elm; |
| 1486 | |
| 1487 | elm = NEW(Objlist_Entry); |
| 1488 | elm->obj = obj; |
| 1489 | STAILQ_INSERT_TAIL(list, elm, link); |
| 1490 | } |
| 1491 | |
| 1492 | static void |
| 1493 | objlist_remove(Objlist *list, Obj_Entry *obj) |
| 1494 | { |
| 1495 | Objlist_Entry *elm; |
| 1496 | |
| 1497 | if ((elm = objlist_find(list, obj)) != NULL) { |
| 1498 | STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); |
| 1499 | free(elm); |
| 1500 | } |
| 1501 | } |
| 1502 | |
| 1503 | /* |
| 1504 | * Remove all of the unreferenced objects from "list". |
| 1505 | */ |
| 1506 | static void |
| 1507 | objlist_remove_unref(Objlist *list) |
| 1508 | { |
| 1509 | Objlist newlist; |
| 1510 | Objlist_Entry *elm; |
| 1511 | |
| 1512 | STAILQ_INIT(&newlist); |
| 1513 | while (!STAILQ_EMPTY(list)) { |
| 1514 | elm = STAILQ_FIRST(list); |
| 1515 | STAILQ_REMOVE_HEAD(list, link); |
| 1516 | if (elm->obj->refcount == 0) |
| 1517 | free(elm); |
| 1518 | else |
| 1519 | STAILQ_INSERT_TAIL(&newlist, elm, link); |
| 1520 | } |
| 1521 | *list = newlist; |
| 1522 | } |
| 1523 | |
| 1524 | /* |
| 1525 | * Relocate newly-loaded shared objects. The argument is a pointer to |
| 1526 | * the Obj_Entry for the first such object. All objects from the first |
| 1527 | * to the end of the list of objects are relocated. Returns 0 on success, |
| 1528 | * or -1 on failure. |
| 1529 | */ |
| 1530 | static int |
| 1531 | relocate_objects(Obj_Entry *first, bool bind_now) |
| 1532 | { |
| 1533 | Obj_Entry *obj; |
| 1534 | |
| 1535 | for (obj = first; obj != NULL; obj = obj->next) { |
| 1536 | if (obj != &obj_rtld) |
| 1537 | dbg("relocating \"%s\"", obj->path); |
| 1538 | if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL || |
| 1539 | obj->symtab == NULL || obj->strtab == NULL) { |
| 1540 | _rtld_error("%s: Shared object has no run-time symbol table", |
| 1541 | obj->path); |
| 1542 | return -1; |
| 1543 | } |
| 1544 | |
| 1545 | if (obj->textrel) { |
| 1546 | /* There are relocations to the write-protected text segment. */ |
| 1547 | if (mprotect(obj->mapbase, obj->textsize, |
| 1548 | PROT_READ|PROT_WRITE|PROT_EXEC) == -1) { |
| 1549 | _rtld_error("%s: Cannot write-enable text segment: %s", |
| 1550 | obj->path, strerror(errno)); |
| 1551 | return -1; |
| 1552 | } |
| 1553 | } |
| 1554 | |
| 1555 | /* Process the non-PLT relocations. */ |
| 1556 | if (reloc_non_plt(obj, &obj_rtld)) |
| 1557 | return -1; |
| 1558 | |
| 1559 | /* |
| 1560 | * Reprotect the text segment. Make sure it is included in the |
| 1561 | * core dump since we modified it. This unfortunately causes the |
| 1562 | * entire text segment to core-out but we don't have much of a |
| 1563 | * choice. We could try to only reenable core dumps on pages |
| 1564 | * in which relocations occured but that is likely most of the text |
| 1565 | * pages anyway, and even that would not work because the rest of |
| 1566 | * the text pages would wind up as a read-only OBJT_DEFAULT object |
| 1567 | * (created due to our modifications) backed by the original OBJT_VNODE |
| 1568 | * object, and the ELF coredump code is currently only able to dump |
| 1569 | * vnode records for pure vnode-backed mappings, not vnode backings |
| 1570 | * to memory objects. |
| 1571 | */ |
| 1572 | if (obj->textrel) { |
| 1573 | madvise(obj->mapbase, obj->textsize, MADV_CORE); |
| 1574 | if (mprotect(obj->mapbase, obj->textsize, |
| 1575 | PROT_READ|PROT_EXEC) == -1) { |
| 1576 | _rtld_error("%s: Cannot write-protect text segment: %s", |
| 1577 | obj->path, strerror(errno)); |
| 1578 | return -1; |
| 1579 | } |
| 1580 | } |
| 1581 | |
| 1582 | /* Process the PLT relocations. */ |
| 1583 | if (reloc_plt(obj) == -1) |
| 1584 | return -1; |
| 1585 | /* Relocate the jump slots if we are doing immediate binding. */ |
| 1586 | if (obj->bind_now || bind_now) |
| 1587 | if (reloc_jmpslots(obj) == -1) |
| 1588 | return -1; |
| 1589 | |
| 1590 | |
| 1591 | /* |
| 1592 | * Set up the magic number and version in the Obj_Entry. These |
| 1593 | * were checked in the crt1.o from the original ElfKit, so we |
| 1594 | * set them for backward compatibility. |
| 1595 | */ |
| 1596 | obj->magic = RTLD_MAGIC; |
| 1597 | obj->version = RTLD_VERSION; |
| 1598 | |
| 1599 | /* Set the special PLT or GOT entries. */ |
| 1600 | init_pltgot(obj); |
| 1601 | } |
| 1602 | |
| 1603 | return 0; |
| 1604 | } |
| 1605 | |
| 1606 | /* |
| 1607 | * Cleanup procedure. It will be called (by the atexit mechanism) just |
| 1608 | * before the process exits. |
| 1609 | */ |
| 1610 | static void |
| 1611 | rtld_exit(void) |
| 1612 | { |
| 1613 | Obj_Entry *obj; |
| 1614 | |
| 1615 | dbg("rtld_exit()"); |
| 1616 | /* Clear all the reference counts so the fini functions will be called. */ |
| 1617 | for (obj = obj_list; obj != NULL; obj = obj->next) |
| 1618 | obj->refcount = 0; |
| 1619 | objlist_call_fini(&list_fini); |
| 1620 | /* No need to remove the items from the list, since we are exiting. */ |
| 1621 | } |
| 1622 | |
| 1623 | static void * |
| 1624 | path_enumerate(const char *path, path_enum_proc callback, void *arg) |
| 1625 | { |
| 1626 | if (path == NULL) |
| 1627 | return (NULL); |
| 1628 | |
| 1629 | path += strspn(path, ":;"); |
| 1630 | while (*path != '\0') { |
| 1631 | size_t len; |
| 1632 | char *res; |
| 1633 | |
| 1634 | len = strcspn(path, ":;"); |
| 1635 | res = callback(path, len, arg); |
| 1636 | |
| 1637 | if (res != NULL) |
| 1638 | return (res); |
| 1639 | |
| 1640 | path += len; |
| 1641 | path += strspn(path, ":;"); |
| 1642 | } |
| 1643 | |
| 1644 | return (NULL); |
| 1645 | } |
| 1646 | |
| 1647 | struct try_library_args { |
| 1648 | const char *name; |
| 1649 | size_t namelen; |
| 1650 | char *buffer; |
| 1651 | size_t buflen; |
| 1652 | }; |
| 1653 | |
| 1654 | static void * |
| 1655 | try_library_path(const char *dir, size_t dirlen, void *param) |
| 1656 | { |
| 1657 | struct try_library_args *arg; |
| 1658 | |
| 1659 | arg = param; |
| 1660 | if (*dir == '/' || trust) { |
| 1661 | char *pathname; |
| 1662 | |
| 1663 | if (dirlen + 1 + arg->namelen + 1 > arg->buflen) |
| 1664 | return (NULL); |
| 1665 | |
| 1666 | pathname = arg->buffer; |
| 1667 | strncpy(pathname, dir, dirlen); |
| 1668 | pathname[dirlen] = '/'; |
| 1669 | strcpy(pathname + dirlen + 1, arg->name); |
| 1670 | |
| 1671 | dbg(" Trying \"%s\"", pathname); |
| 1672 | if (access(pathname, F_OK) == 0) { /* We found it */ |
| 1673 | pathname = xmalloc(dirlen + 1 + arg->namelen + 1); |
| 1674 | strcpy(pathname, arg->buffer); |
| 1675 | return (pathname); |
| 1676 | } |
| 1677 | } |
| 1678 | return (NULL); |
| 1679 | } |
| 1680 | |
| 1681 | static char * |
| 1682 | search_library_path(const char *name, const char *path) |
| 1683 | { |
| 1684 | char *p; |
| 1685 | struct try_library_args arg; |
| 1686 | |
| 1687 | if (path == NULL) |
| 1688 | return NULL; |
| 1689 | |
| 1690 | arg.name = name; |
| 1691 | arg.namelen = strlen(name); |
| 1692 | arg.buffer = xmalloc(PATH_MAX); |
| 1693 | arg.buflen = PATH_MAX; |
| 1694 | |
| 1695 | p = path_enumerate(path, try_library_path, &arg); |
| 1696 | |
| 1697 | free(arg.buffer); |
| 1698 | |
| 1699 | return (p); |
| 1700 | } |
| 1701 | |
| 1702 | int |
| 1703 | dlclose(void *handle) |
| 1704 | { |
| 1705 | Obj_Entry *root; |
| 1706 | |
| 1707 | wlock_acquire(); |
| 1708 | root = dlcheck(handle); |
| 1709 | if (root == NULL) { |
| 1710 | wlock_release(); |
| 1711 | return -1; |
| 1712 | } |
| 1713 | |
| 1714 | /* Unreference the object and its dependencies. */ |
| 1715 | root->dl_refcount--; |
| 1716 | unref_dag(root); |
| 1717 | |
| 1718 | if (root->refcount == 0) { |
| 1719 | /* |
| 1720 | * The object is no longer referenced, so we must unload it. |
| 1721 | * First, call the fini functions with no locks held. |
| 1722 | */ |
| 1723 | wlock_release(); |
| 1724 | objlist_call_fini(&list_fini); |
| 1725 | wlock_acquire(); |
| 1726 | objlist_remove_unref(&list_fini); |
| 1727 | |
| 1728 | /* Finish cleaning up the newly-unreferenced objects. */ |
| 1729 | GDB_STATE(RT_DELETE,&root->linkmap); |
| 1730 | unload_object(root); |
| 1731 | GDB_STATE(RT_CONSISTENT,NULL); |
| 1732 | } |
| 1733 | wlock_release(); |
| 1734 | return 0; |
| 1735 | } |
| 1736 | |
| 1737 | const char * |
| 1738 | dlerror(void) |
| 1739 | { |
| 1740 | char *msg = error_message; |
| 1741 | error_message = NULL; |
| 1742 | return msg; |
| 1743 | } |
| 1744 | |
| 1745 | void * |
| 1746 | dlopen(const char *name, int mode) |
| 1747 | { |
| 1748 | Obj_Entry **old_obj_tail; |
| 1749 | Obj_Entry *obj; |
| 1750 | Objlist initlist; |
| 1751 | int result; |
| 1752 | |
| 1753 | ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; |
| 1754 | if (ld_tracing != NULL) |
| 1755 | environ = (char **)*get_program_var_addr("environ"); |
| 1756 | |
| 1757 | objlist_init(&initlist); |
| 1758 | |
| 1759 | wlock_acquire(); |
| 1760 | GDB_STATE(RT_ADD,NULL); |
| 1761 | |
| 1762 | old_obj_tail = obj_tail; |
| 1763 | obj = NULL; |
| 1764 | if (name == NULL) { |
| 1765 | obj = obj_main; |
| 1766 | obj->refcount++; |
| 1767 | } else { |
| 1768 | char *path = find_library(name, obj_main); |
| 1769 | if (path != NULL) |
| 1770 | obj = load_object(path); |
| 1771 | } |
| 1772 | |
| 1773 | if (obj) { |
| 1774 | obj->dl_refcount++; |
| 1775 | if ((mode & RTLD_GLOBAL) && objlist_find(&list_global, obj) == NULL) |
| 1776 | objlist_push_tail(&list_global, obj); |
| 1777 | mode &= RTLD_MODEMASK; |
| 1778 | if (*old_obj_tail != NULL) { /* We loaded something new. */ |
| 1779 | assert(*old_obj_tail == obj); |
| 1780 | |
| 1781 | result = load_needed_objects(obj); |
| 1782 | if (result != -1 && ld_tracing) |
| 1783 | goto trace; |
| 1784 | |
| 1785 | if (result == -1 || |
| 1786 | (init_dag(obj), relocate_objects(obj, mode == RTLD_NOW)) == -1) { |
| 1787 | obj->dl_refcount--; |
| 1788 | unref_dag(obj); |
| 1789 | if (obj->refcount == 0) |
| 1790 | unload_object(obj); |
| 1791 | obj = NULL; |
| 1792 | } else { |
| 1793 | /* Make list of init functions to call. */ |
| 1794 | initlist_add_objects(obj, &obj->next, &initlist); |
| 1795 | } |
| 1796 | } else if (ld_tracing) |
| 1797 | goto trace; |
| 1798 | } |
| 1799 | |
| 1800 | GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL); |
| 1801 | |
| 1802 | /* Call the init functions with no locks held. */ |
| 1803 | wlock_release(); |
| 1804 | objlist_call_init(&initlist); |
| 1805 | wlock_acquire(); |
| 1806 | objlist_clear(&initlist); |
| 1807 | wlock_release(); |
| 1808 | return obj; |
| 1809 | trace: |
| 1810 | trace_loaded_objects(obj); |
| 1811 | wlock_release(); |
| 1812 | exit(0); |
| 1813 | } |
| 1814 | |
| 1815 | void * |
| 1816 | dlsym(void *handle, const char *name) |
| 1817 | { |
| 1818 | const Obj_Entry *obj; |
| 1819 | unsigned long hash; |
| 1820 | const Elf_Sym *def; |
| 1821 | const Obj_Entry *defobj; |
| 1822 | |
| 1823 | hash = elf_hash(name); |
| 1824 | def = NULL; |
| 1825 | defobj = NULL; |
| 1826 | |
| 1827 | rlock_acquire(); |
| 1828 | if (handle == NULL || handle == RTLD_NEXT || |
| 1829 | handle == RTLD_DEFAULT || handle == RTLD_SELF) { |
| 1830 | void *retaddr; |
| 1831 | |
| 1832 | retaddr = __builtin_return_address(0); /* __GNUC__ only */ |
| 1833 | if ((obj = obj_from_addr(retaddr)) == NULL) { |
| 1834 | _rtld_error("Cannot determine caller's shared object"); |
| 1835 | rlock_release(); |
| 1836 | return NULL; |
| 1837 | } |
| 1838 | if (handle == NULL) { /* Just the caller's shared object. */ |
| 1839 | def = symlook_obj(name, hash, obj, true); |
| 1840 | defobj = obj; |
| 1841 | } else if (handle == RTLD_NEXT || /* Objects after caller's */ |
| 1842 | handle == RTLD_SELF) { /* ... caller included */ |
| 1843 | if (handle == RTLD_NEXT) |
| 1844 | obj = obj->next; |
| 1845 | for (; obj != NULL; obj = obj->next) { |
| 1846 | if ((def = symlook_obj(name, hash, obj, true)) != NULL) { |
| 1847 | defobj = obj; |
| 1848 | break; |
| 1849 | } |
| 1850 | } |
| 1851 | } else { |
| 1852 | assert(handle == RTLD_DEFAULT); |
| 1853 | def = symlook_default(name, hash, obj, &defobj, true); |
| 1854 | } |
| 1855 | } else { |
| 1856 | if ((obj = dlcheck(handle)) == NULL) { |
| 1857 | rlock_release(); |
| 1858 | return NULL; |
| 1859 | } |
| 1860 | |
| 1861 | if (obj->mainprog) { |
| 1862 | DoneList donelist; |
| 1863 | |
| 1864 | /* Search main program and all libraries loaded by it. */ |
| 1865 | donelist_init(&donelist); |
| 1866 | def = symlook_list(name, hash, &list_main, &defobj, true, |
| 1867 | &donelist); |
| 1868 | } else { |
| 1869 | /* |
| 1870 | * XXX - This isn't correct. The search should include the whole |
| 1871 | * DAG rooted at the given object. |
| 1872 | */ |
| 1873 | def = symlook_obj(name, hash, obj, true); |
| 1874 | defobj = obj; |
| 1875 | } |
| 1876 | } |
| 1877 | |
| 1878 | if (def != NULL) { |
| 1879 | rlock_release(); |
| 1880 | return defobj->relocbase + def->st_value; |
| 1881 | } |
| 1882 | |
| 1883 | _rtld_error("Undefined symbol \"%s\"", name); |
| 1884 | rlock_release(); |
| 1885 | return NULL; |
| 1886 | } |
| 1887 | |
| 1888 | int |
| 1889 | dladdr(const void *addr, Dl_info *info) |
| 1890 | { |
| 1891 | const Obj_Entry *obj; |
| 1892 | const Elf_Sym *def; |
| 1893 | void *symbol_addr; |
| 1894 | unsigned long symoffset; |
| 1895 | |
| 1896 | rlock_acquire(); |
| 1897 | obj = obj_from_addr(addr); |
| 1898 | if (obj == NULL) { |
| 1899 | _rtld_error("No shared object contains address"); |
| 1900 | rlock_release(); |
| 1901 | return 0; |
| 1902 | } |
| 1903 | info->dli_fname = obj->path; |
| 1904 | info->dli_fbase = obj->mapbase; |
| 1905 | info->dli_saddr = (void *)0; |
| 1906 | info->dli_sname = NULL; |
| 1907 | |
| 1908 | /* |
| 1909 | * Walk the symbol list looking for the symbol whose address is |
| 1910 | * closest to the address sent in. |
| 1911 | */ |
| 1912 | for (symoffset = 0; symoffset < obj->nchains; symoffset++) { |
| 1913 | def = obj->symtab + symoffset; |
| 1914 | |
| 1915 | /* |
| 1916 | * For skip the symbol if st_shndx is either SHN_UNDEF or |
| 1917 | * SHN_COMMON. |
| 1918 | */ |
| 1919 | if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) |
| 1920 | continue; |
| 1921 | |
| 1922 | /* |
| 1923 | * If the symbol is greater than the specified address, or if it |
| 1924 | * is further away from addr than the current nearest symbol, |
| 1925 | * then reject it. |
| 1926 | */ |
| 1927 | symbol_addr = obj->relocbase + def->st_value; |
| 1928 | if (symbol_addr > addr || symbol_addr < info->dli_saddr) |
| 1929 | continue; |
| 1930 | |
| 1931 | /* Update our idea of the nearest symbol. */ |
| 1932 | info->dli_sname = obj->strtab + def->st_name; |
| 1933 | info->dli_saddr = symbol_addr; |
| 1934 | |
| 1935 | /* Exact match? */ |
| 1936 | if (info->dli_saddr == addr) |
| 1937 | break; |
| 1938 | } |
| 1939 | rlock_release(); |
| 1940 | return 1; |
| 1941 | } |
| 1942 | |
| 1943 | int |
| 1944 | dlinfo(void *handle, int request, void *p) |
| 1945 | { |
| 1946 | const Obj_Entry *obj; |
| 1947 | int error; |
| 1948 | |
| 1949 | rlock_acquire(); |
| 1950 | |
| 1951 | if (handle == NULL || handle == RTLD_SELF) { |
| 1952 | void *retaddr; |
| 1953 | |
| 1954 | retaddr = __builtin_return_address(0); /* __GNUC__ only */ |
| 1955 | if ((obj = obj_from_addr(retaddr)) == NULL) |
| 1956 | _rtld_error("Cannot determine caller's shared object"); |
| 1957 | } else |
| 1958 | obj = dlcheck(handle); |
| 1959 | |
| 1960 | if (obj == NULL) { |
| 1961 | rlock_release(); |
| 1962 | return (-1); |
| 1963 | } |
| 1964 | |
| 1965 | error = 0; |
| 1966 | switch (request) { |
| 1967 | case RTLD_DI_LINKMAP: |
| 1968 | *((struct link_map const **)p) = &obj->linkmap; |
| 1969 | break; |
| 1970 | case RTLD_DI_ORIGIN: |
| 1971 | error = rtld_dirname(obj->path, p); |
| 1972 | break; |
| 1973 | |
| 1974 | case RTLD_DI_SERINFOSIZE: |
| 1975 | case RTLD_DI_SERINFO: |
| 1976 | error = do_search_info(obj, request, (struct dl_serinfo *)p); |
| 1977 | break; |
| 1978 | |
| 1979 | default: |
| 1980 | _rtld_error("Invalid request %d passed to dlinfo()", request); |
| 1981 | error = -1; |
| 1982 | } |
| 1983 | |
| 1984 | rlock_release(); |
| 1985 | |
| 1986 | return (error); |
| 1987 | } |
| 1988 | |
| 1989 | struct fill_search_info_args { |
| 1990 | int request; |
| 1991 | unsigned int flags; |
| 1992 | Dl_serinfo *serinfo; |
| 1993 | Dl_serpath *serpath; |
| 1994 | char *strspace; |
| 1995 | }; |
| 1996 | |
| 1997 | static void * |
| 1998 | fill_search_info(const char *dir, size_t dirlen, void *param) |
| 1999 | { |
| 2000 | struct fill_search_info_args *arg; |
| 2001 | |
| 2002 | arg = param; |
| 2003 | |
| 2004 | if (arg->request == RTLD_DI_SERINFOSIZE) { |
| 2005 | arg->serinfo->dls_cnt ++; |
| 2006 | arg->serinfo->dls_size += dirlen + 1; |
| 2007 | } else { |
| 2008 | struct dl_serpath *s_entry; |
| 2009 | |
| 2010 | s_entry = arg->serpath; |
| 2011 | s_entry->dls_name = arg->strspace; |
| 2012 | s_entry->dls_flags = arg->flags; |
| 2013 | |
| 2014 | strncpy(arg->strspace, dir, dirlen); |
| 2015 | arg->strspace[dirlen] = '\0'; |
| 2016 | |
| 2017 | arg->strspace += dirlen + 1; |
| 2018 | arg->serpath++; |
| 2019 | } |
| 2020 | |
| 2021 | return (NULL); |
| 2022 | } |
| 2023 | |
| 2024 | static int |
| 2025 | do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) |
| 2026 | { |
| 2027 | struct dl_serinfo _info; |
| 2028 | struct fill_search_info_args args; |
| 2029 | |
| 2030 | args.request = RTLD_DI_SERINFOSIZE; |
| 2031 | args.serinfo = &_info; |
| 2032 | |
| 2033 | _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); |
| 2034 | _info.dls_cnt = 0; |
| 2035 | |
| 2036 | path_enumerate(ld_library_path, fill_search_info, &args); |
| 2037 | path_enumerate(obj->rpath, fill_search_info, &args); |
| 2038 | path_enumerate(gethints(), fill_search_info, &args); |
| 2039 | path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args); |
| 2040 | |
| 2041 | |
| 2042 | if (request == RTLD_DI_SERINFOSIZE) { |
| 2043 | info->dls_size = _info.dls_size; |
| 2044 | info->dls_cnt = _info.dls_cnt; |
| 2045 | return (0); |
| 2046 | } |
| 2047 | |
| 2048 | if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { |
| 2049 | _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()"); |
| 2050 | return (-1); |
| 2051 | } |
| 2052 | |
| 2053 | args.request = RTLD_DI_SERINFO; |
| 2054 | args.serinfo = info; |
| 2055 | args.serpath = &info->dls_serpath[0]; |
| 2056 | args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; |
| 2057 | |
| 2058 | args.flags = LA_SER_LIBPATH; |
| 2059 | if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL) |
| 2060 | return (-1); |
| 2061 | |
| 2062 | args.flags = LA_SER_RUNPATH; |
| 2063 | if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL) |
| 2064 | return (-1); |
| 2065 | |
| 2066 | args.flags = LA_SER_CONFIG; |
| 2067 | if (path_enumerate(gethints(), fill_search_info, &args) != NULL) |
| 2068 | return (-1); |
| 2069 | |
| 2070 | args.flags = LA_SER_DEFAULT; |
| 2071 | if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL) |
| 2072 | return (-1); |
| 2073 | return (0); |
| 2074 | } |
| 2075 | |
| 2076 | static int |
| 2077 | rtld_dirname(const char *path, char *bname) |
| 2078 | { |
| 2079 | const char *endp; |
| 2080 | |
| 2081 | /* Empty or NULL string gets treated as "." */ |
| 2082 | if (path == NULL || *path == '\0') { |
| 2083 | bname[0] = '.'; |
| 2084 | bname[1] = '\0'; |
| 2085 | return (0); |
| 2086 | } |
| 2087 | |
| 2088 | /* Strip trailing slashes */ |
| 2089 | endp = path + strlen(path) - 1; |
| 2090 | while (endp > path && *endp == '/') |
| 2091 | endp--; |
| 2092 | |
| 2093 | /* Find the start of the dir */ |
| 2094 | while (endp > path && *endp != '/') |
| 2095 | endp--; |
| 2096 | |
| 2097 | /* Either the dir is "/" or there are no slashes */ |
| 2098 | if (endp == path) { |
| 2099 | bname[0] = *endp == '/' ? '/' : '.'; |
| 2100 | bname[1] = '\0'; |
| 2101 | return (0); |
| 2102 | } else { |
| 2103 | do { |
| 2104 | endp--; |
| 2105 | } while (endp > path && *endp == '/'); |
| 2106 | } |
| 2107 | |
| 2108 | if (endp - path + 2 > PATH_MAX) |
| 2109 | { |
| 2110 | _rtld_error("Filename is too long: %s", path); |
| 2111 | return(-1); |
| 2112 | } |
| 2113 | |
| 2114 | strncpy(bname, path, endp - path + 1); |
| 2115 | bname[endp - path + 1] = '\0'; |
| 2116 | return (0); |
| 2117 | } |
| 2118 | |
| 2119 | static void |
| 2120 | linkmap_add(Obj_Entry *obj) |
| 2121 | { |
| 2122 | struct link_map *l = &obj->linkmap; |
| 2123 | struct link_map *prev; |
| 2124 | |
| 2125 | obj->linkmap.l_name = obj->path; |
| 2126 | obj->linkmap.l_addr = obj->mapbase; |
| 2127 | obj->linkmap.l_ld = obj->dynamic; |
| 2128 | #ifdef __mips__ |
| 2129 | /* GDB needs load offset on MIPS to use the symbols */ |
| 2130 | obj->linkmap.l_offs = obj->relocbase; |
| 2131 | #endif |
| 2132 | |
| 2133 | if (r_debug.r_map == NULL) { |
| 2134 | r_debug.r_map = l; |
| 2135 | return; |
| 2136 | } |
| 2137 | |
| 2138 | /* |
| 2139 | * Scan to the end of the list, but not past the entry for the |
| 2140 | * dynamic linker, which we want to keep at the very end. |
| 2141 | */ |
| 2142 | for (prev = r_debug.r_map; |
| 2143 | prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; |
| 2144 | prev = prev->l_next) |
| 2145 | ; |
| 2146 | |
| 2147 | /* Link in the new entry. */ |
| 2148 | l->l_prev = prev; |
| 2149 | l->l_next = prev->l_next; |
| 2150 | if (l->l_next != NULL) |
| 2151 | l->l_next->l_prev = l; |
| 2152 | prev->l_next = l; |
| 2153 | } |
| 2154 | |
| 2155 | static void |
| 2156 | linkmap_delete(Obj_Entry *obj) |
| 2157 | { |
| 2158 | struct link_map *l = &obj->linkmap; |
| 2159 | |
| 2160 | if (l->l_prev == NULL) { |
| 2161 | if ((r_debug.r_map = l->l_next) != NULL) |
| 2162 | l->l_next->l_prev = NULL; |
| 2163 | return; |
| 2164 | } |
| 2165 | |
| 2166 | if ((l->l_prev->l_next = l->l_next) != NULL) |
| 2167 | l->l_next->l_prev = l->l_prev; |
| 2168 | } |
| 2169 | |
| 2170 | /* |
| 2171 | * Function for the debugger to set a breakpoint on to gain control. |
| 2172 | * |
| 2173 | * The two parameters allow the debugger to easily find and determine |
| 2174 | * what the runtime loader is doing and to whom it is doing it. |
| 2175 | * |
| 2176 | * When the loadhook trap is hit (r_debug_state, set at program |
| 2177 | * initialization), the arguments can be found on the stack: |
| 2178 | * |
| 2179 | * +8 struct link_map *m |
| 2180 | * +4 struct r_debug *rd |
| 2181 | * +0 RetAddr |
| 2182 | */ |
| 2183 | void |
| 2184 | r_debug_state(struct r_debug* rd, struct link_map *m) |
| 2185 | { |
| 2186 | } |
| 2187 | |
| 2188 | /* |
| 2189 | * Get address of the pointer variable in the main program. |
| 2190 | */ |
| 2191 | static const void ** |
| 2192 | get_program_var_addr(const char *name) |
| 2193 | { |
| 2194 | const Obj_Entry *obj; |
| 2195 | unsigned long hash; |
| 2196 | |
| 2197 | hash = elf_hash(name); |
| 2198 | for (obj = obj_main; obj != NULL; obj = obj->next) { |
| 2199 | const Elf_Sym *def; |
| 2200 | |
| 2201 | if ((def = symlook_obj(name, hash, obj, false)) != NULL) { |
| 2202 | const void **addr; |
| 2203 | |
| 2204 | addr = (const void **)(obj->relocbase + def->st_value); |
| 2205 | return addr; |
| 2206 | } |
| 2207 | } |
| 2208 | return NULL; |
| 2209 | } |
| 2210 | |
| 2211 | /* |
| 2212 | * Set a pointer variable in the main program to the given value. This |
| 2213 | * is used to set key variables such as "environ" before any of the |
| 2214 | * init functions are called. |
| 2215 | */ |
| 2216 | static void |
| 2217 | set_program_var(const char *name, const void *value) |
| 2218 | { |
| 2219 | const void **addr; |
| 2220 | |
| 2221 | if ((addr = get_program_var_addr(name)) != NULL) { |
| 2222 | dbg("\"%s\": *%p <-- %p", name, addr, value); |
| 2223 | *addr = value; |
| 2224 | } |
| 2225 | } |
| 2226 | |
| 2227 | /* |
| 2228 | * This is a special version of getenv which is far more efficient |
| 2229 | * at finding LD_ environment vars. |
| 2230 | */ |
| 2231 | static |
| 2232 | const char * |
| 2233 | _getenv_ld(const char *id) |
| 2234 | { |
| 2235 | const char *envp; |
| 2236 | int i, j; |
| 2237 | int idlen = strlen(id); |
| 2238 | |
| 2239 | if (ld_index == LD_ARY_CACHE) |
| 2240 | return(getenv(id)); |
| 2241 | if (ld_index == 0) { |
| 2242 | for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) { |
| 2243 | if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_') |
| 2244 | ld_ary[j++] = envp; |
| 2245 | } |
| 2246 | if (j == 0) |
| 2247 | ld_ary[j++] = ""; |
| 2248 | ld_index = j; |
| 2249 | } |
| 2250 | for (i = ld_index - 1; i >= 0; --i) { |
| 2251 | if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=') |
| 2252 | return(ld_ary[i] + idlen + 1); |
| 2253 | } |
| 2254 | return(NULL); |
| 2255 | } |
| 2256 | |
| 2257 | /* |
| 2258 | * Given a symbol name in a referencing object, find the corresponding |
| 2259 | * definition of the symbol. Returns a pointer to the symbol, or NULL if |
| 2260 | * no definition was found. Returns a pointer to the Obj_Entry of the |
| 2261 | * defining object via the reference parameter DEFOBJ_OUT. |
| 2262 | */ |
| 2263 | static const Elf_Sym * |
| 2264 | symlook_default(const char *name, unsigned long hash, |
| 2265 | const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt) |
| 2266 | { |
| 2267 | DoneList donelist; |
| 2268 | const Elf_Sym *def; |
| 2269 | const Elf_Sym *symp; |
| 2270 | const Obj_Entry *obj; |
| 2271 | const Obj_Entry *defobj; |
| 2272 | const Objlist_Entry *elm; |
| 2273 | def = NULL; |
| 2274 | defobj = NULL; |
| 2275 | donelist_init(&donelist); |
| 2276 | |
| 2277 | /* Look first in the referencing object if linked symbolically. */ |
| 2278 | if (refobj->symbolic && !donelist_check(&donelist, refobj)) { |
| 2279 | symp = symlook_obj(name, hash, refobj, in_plt); |
| 2280 | if (symp != NULL) { |
| 2281 | def = symp; |
| 2282 | defobj = refobj; |
| 2283 | } |
| 2284 | } |
| 2285 | |
| 2286 | /* Search all objects loaded at program start up. */ |
| 2287 | if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { |
| 2288 | symp = symlook_list(name, hash, &list_main, &obj, in_plt, &donelist); |
| 2289 | if (symp != NULL && |
| 2290 | (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { |
| 2291 | def = symp; |
| 2292 | defobj = obj; |
| 2293 | } |
| 2294 | } |
| 2295 | |
| 2296 | /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ |
| 2297 | STAILQ_FOREACH(elm, &list_global, link) { |
| 2298 | if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) |
| 2299 | break; |
| 2300 | symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt, |
| 2301 | &donelist); |
| 2302 | if (symp != NULL && |
| 2303 | (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { |
| 2304 | def = symp; |
| 2305 | defobj = obj; |
| 2306 | } |
| 2307 | } |
| 2308 | |
| 2309 | /* Search all dlopened DAGs containing the referencing object. */ |
| 2310 | STAILQ_FOREACH(elm, &refobj->dldags, link) { |
| 2311 | if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK) |
| 2312 | break; |
| 2313 | symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt, |
| 2314 | &donelist); |
| 2315 | if (symp != NULL && |
| 2316 | (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) { |
| 2317 | def = symp; |
| 2318 | defobj = obj; |
| 2319 | } |
| 2320 | } |
| 2321 | |
| 2322 | /* |
| 2323 | * Search the dynamic linker itself, and possibly resolve the |
| 2324 | * symbol from there. This is how the application links to |
| 2325 | * dynamic linker services such as dlopen. Only the values listed |
| 2326 | * in the "exports" array can be resolved from the dynamic linker. |
| 2327 | */ |
| 2328 | if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { |
| 2329 | symp = symlook_obj(name, hash, &obj_rtld, in_plt); |
| 2330 | if (symp != NULL && is_exported(symp)) { |
| 2331 | def = symp; |
| 2332 | defobj = &obj_rtld; |
| 2333 | } |
| 2334 | } |
| 2335 | |
| 2336 | if (def != NULL) |
| 2337 | *defobj_out = defobj; |
| 2338 | return def; |
| 2339 | } |
| 2340 | |
| 2341 | static const Elf_Sym * |
| 2342 | symlook_list(const char *name, unsigned long hash, Objlist *objlist, |
| 2343 | const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp) |
| 2344 | { |
| 2345 | const Elf_Sym *symp; |
| 2346 | const Elf_Sym *def; |
| 2347 | const Obj_Entry *defobj; |
| 2348 | const Objlist_Entry *elm; |
| 2349 | |
| 2350 | def = NULL; |
| 2351 | defobj = NULL; |
| 2352 | STAILQ_FOREACH(elm, objlist, link) { |
| 2353 | if (donelist_check(dlp, elm->obj)) |
| 2354 | continue; |
| 2355 | if ((symp = symlook_obj(name, hash, elm->obj, in_plt)) != NULL) { |
| 2356 | if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) { |
| 2357 | def = symp; |
| 2358 | defobj = elm->obj; |
| 2359 | if (ELF_ST_BIND(def->st_info) != STB_WEAK) |
| 2360 | break; |
| 2361 | } |
| 2362 | } |
| 2363 | } |
| 2364 | if (def != NULL) |
| 2365 | *defobj_out = defobj; |
| 2366 | return def; |
| 2367 | } |
| 2368 | |
| 2369 | /* |
| 2370 | * Search the symbol table of a single shared object for a symbol of |
| 2371 | * the given name. Returns a pointer to the symbol, or NULL if no |
| 2372 | * definition was found. |
| 2373 | * |
| 2374 | * The symbol's hash value is passed in for efficiency reasons; that |
| 2375 | * eliminates many recomputations of the hash value. |
| 2376 | */ |
| 2377 | const Elf_Sym * |
| 2378 | symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj, |
| 2379 | bool in_plt) |
| 2380 | { |
| 2381 | if (obj->buckets != NULL) { |
| 2382 | unsigned long symnum = obj->buckets[hash % obj->nbuckets]; |
| 2383 | |
| 2384 | while (symnum != STN_UNDEF) { |
| 2385 | const Elf_Sym *symp; |
| 2386 | const char *strp; |
| 2387 | |
| 2388 | if (symnum >= obj->nchains) |
| 2389 | return NULL; /* Bad object */ |
| 2390 | symp = obj->symtab + symnum; |
| 2391 | strp = obj->strtab + symp->st_name; |
| 2392 | |
| 2393 | if (name[0] == strp[0] && strcmp(name, strp) == 0) |
| 2394 | return symp->st_shndx != SHN_UNDEF || |
| 2395 | (!in_plt && symp->st_value != 0 && |
| 2396 | ELF_ST_TYPE(symp->st_info) == STT_FUNC) ? symp : NULL; |
| 2397 | |
| 2398 | symnum = obj->chains[symnum]; |
| 2399 | } |
| 2400 | } |
| 2401 | return NULL; |
| 2402 | } |
| 2403 | |
| 2404 | static void |
| 2405 | trace_loaded_objects(Obj_Entry *obj) |
| 2406 | { |
| 2407 | const char *fmt1, *fmt2, *fmt, *main_local; |
| 2408 | int c; |
| 2409 | |
| 2410 | if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL) |
| 2411 | main_local = ""; |
| 2412 | |
| 2413 | if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL) |
| 2414 | fmt1 = "\t%o => %p (%x)\n"; |
| 2415 | |
| 2416 | if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL) |
| 2417 | fmt2 = "\t%o (%x)\n"; |
| 2418 | |
| 2419 | for (; obj; obj = obj->next) { |
| 2420 | Needed_Entry *needed; |
| 2421 | char *name, *path; |
| 2422 | bool is_lib; |
| 2423 | |
| 2424 | for (needed = obj->needed; needed; needed = needed->next) { |
| 2425 | if (needed->obj != NULL) { |
| 2426 | if (needed->obj->traced) |
| 2427 | continue; |
| 2428 | needed->obj->traced = true; |
| 2429 | path = needed->obj->path; |
| 2430 | } else |
| 2431 | path = "not found"; |
| 2432 | |
| 2433 | name = (char *)obj->strtab + needed->name; |
| 2434 | is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */ |
| 2435 | |
| 2436 | fmt = is_lib ? fmt1 : fmt2; |
| 2437 | while ((c = *fmt++) != '\0') { |
| 2438 | switch (c) { |
| 2439 | default: |
| 2440 | putchar(c); |
| 2441 | continue; |
| 2442 | case '\\': |
| 2443 | switch (c = *fmt) { |
| 2444 | case '\0': |
| 2445 | continue; |
| 2446 | case 'n': |
| 2447 | putchar('\n'); |
| 2448 | break; |
| 2449 | case 't': |
| 2450 | putchar('\t'); |
| 2451 | break; |
| 2452 | } |
| 2453 | break; |
| 2454 | case '%': |
| 2455 | switch (c = *fmt) { |
| 2456 | case '\0': |
| 2457 | continue; |
| 2458 | case '%': |
| 2459 | default: |
| 2460 | putchar(c); |
| 2461 | break; |
| 2462 | case 'A': |
| 2463 | printf("%s", main_local); |
| 2464 | break; |
| 2465 | case 'a': |
| 2466 | printf("%s", obj_main->path); |
| 2467 | break; |
| 2468 | case 'o': |
| 2469 | printf("%s", name); |
| 2470 | break; |
| 2471 | #if 0 |
| 2472 | case 'm': |
| 2473 | printf("%d", sodp->sod_major); |
| 2474 | break; |
| 2475 | case 'n': |
| 2476 | printf("%d", sodp->sod_minor); |
| 2477 | break; |
| 2478 | #endif |
| 2479 | case 'p': |
| 2480 | printf("%s", path); |
| 2481 | break; |
| 2482 | case 'x': |
| 2483 | printf("%p", needed->obj ? needed->obj->mapbase : 0); |
| 2484 | break; |
| 2485 | } |
| 2486 | break; |
| 2487 | } |
| 2488 | ++fmt; |
| 2489 | } |
| 2490 | } |
| 2491 | } |
| 2492 | } |
| 2493 | |
| 2494 | /* |
| 2495 | * Unload a dlopened object and its dependencies from memory and from |
| 2496 | * our data structures. It is assumed that the DAG rooted in the |
| 2497 | * object has already been unreferenced, and that the object has a |
| 2498 | * reference count of 0. |
| 2499 | */ |
| 2500 | static void |
| 2501 | unload_object(Obj_Entry *root) |
| 2502 | { |
| 2503 | Obj_Entry *obj; |
| 2504 | Obj_Entry **linkp; |
| 2505 | |
| 2506 | assert(root->refcount == 0); |
| 2507 | |
| 2508 | /* |
| 2509 | * Pass over the DAG removing unreferenced objects from |
| 2510 | * appropriate lists. |
| 2511 | */ |
| 2512 | unlink_object(root); |
| 2513 | |
| 2514 | /* Unmap all objects that are no longer referenced. */ |
| 2515 | linkp = &obj_list->next; |
| 2516 | while ((obj = *linkp) != NULL) { |
| 2517 | if (obj->refcount == 0) { |
| 2518 | dbg("unloading \"%s\"", obj->path); |
| 2519 | munmap(obj->mapbase, obj->mapsize); |
| 2520 | linkmap_delete(obj); |
| 2521 | *linkp = obj->next; |
| 2522 | obj_count--; |
| 2523 | obj_free(obj); |
| 2524 | } else |
| 2525 | linkp = &obj->next; |
| 2526 | } |
| 2527 | obj_tail = linkp; |
| 2528 | } |
| 2529 | |
| 2530 | static void |
| 2531 | unlink_object(Obj_Entry *root) |
| 2532 | { |
| 2533 | const Needed_Entry *needed; |
| 2534 | Objlist_Entry *elm; |
| 2535 | |
| 2536 | if (root->refcount == 0) { |
| 2537 | /* Remove the object from the RTLD_GLOBAL list. */ |
| 2538 | objlist_remove(&list_global, root); |
| 2539 | |
| 2540 | /* Remove the object from all objects' DAG lists. */ |
| 2541 | STAILQ_FOREACH(elm, &root->dagmembers , link) |
| 2542 | objlist_remove(&elm->obj->dldags, root); |
| 2543 | } |
| 2544 | |
| 2545 | for (needed = root->needed; needed != NULL; needed = needed->next) |
| 2546 | if (needed->obj != NULL) |
| 2547 | unlink_object(needed->obj); |
| 2548 | } |
| 2549 | |
| 2550 | static void |
| 2551 | unref_dag(Obj_Entry *root) |
| 2552 | { |
| 2553 | const Needed_Entry *needed; |
| 2554 | |
| 2555 | if (root->refcount == 0) |
| 2556 | return; |
| 2557 | root->refcount--; |
| 2558 | if (root->refcount == 0) |
| 2559 | for (needed = root->needed; needed != NULL; needed = needed->next) |
| 2560 | if (needed->obj != NULL) |
| 2561 | unref_dag(needed->obj); |
| 2562 | } |
| 2563 | |
| 2564 | /* |
| 2565 | * Common code for MD __tls_get_addr(). |
| 2566 | */ |
| 2567 | void * |
| 2568 | tls_get_addr_common(void **dtvp, int index, size_t offset) |
| 2569 | { |
| 2570 | Elf_Addr* dtv = *dtvp; |
| 2571 | |
| 2572 | /* Check dtv generation in case new modules have arrived */ |
| 2573 | if (dtv[0] != tls_dtv_generation) { |
| 2574 | Elf_Addr* newdtv; |
| 2575 | int to_copy; |
| 2576 | |
| 2577 | wlock_acquire(); |
| 2578 | |
| 2579 | newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr)); |
| 2580 | to_copy = dtv[1]; |
| 2581 | if (to_copy > tls_max_index) |
| 2582 | to_copy = tls_max_index; |
| 2583 | memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr)); |
| 2584 | newdtv[0] = tls_dtv_generation; |
| 2585 | newdtv[1] = tls_max_index; |
| 2586 | free(dtv); |
| 2587 | *dtvp = newdtv; |
| 2588 | |
| 2589 | wlock_release(); |
| 2590 | } |
| 2591 | |
| 2592 | /* Dynamically allocate module TLS if necessary */ |
| 2593 | if (!dtv[index + 1]) { |
| 2594 | /* XXX |
| 2595 | * here we should avoid to be re-entered by signal handler |
| 2596 | * code, I assume wlock_acquire will masked all signals, |
| 2597 | * otherwise there is race and dead lock thread itself. |
| 2598 | */ |
| 2599 | wlock_acquire(); |
| 2600 | if (!dtv[index + 1]) |
| 2601 | dtv[index + 1] = (Elf_Addr)allocate_module_tls(index); |
| 2602 | wlock_release(); |
| 2603 | } |
| 2604 | |
| 2605 | return (void*) (dtv[index + 1] + offset); |
| 2606 | } |
| 2607 | |
| 2608 | #if defined(RTLD_STATIC_TLS_VARIANT_II) |
| 2609 | |
| 2610 | /* |
| 2611 | * Allocate the static TLS area. Return a pointer to the TCB. The |
| 2612 | * static area is based on negative offsets relative to the tcb. |
| 2613 | * |
| 2614 | * The TCB contains an errno pointer for the system call layer, but because |
| 2615 | * we are the RTLD we really have no idea how the caller was compiled so |
| 2616 | * the information has to be passed in. errno can either be: |
| 2617 | * |
| 2618 | * type 0 errno is a simple non-TLS global pointer. |
| 2619 | * (special case for e.g. libc_rtld) |
| 2620 | * type 1 errno accessed by GOT entry (dynamically linked programs) |
| 2621 | * type 2 errno accessed by %gs:OFFSET (statically linked programs) |
| 2622 | */ |
| 2623 | struct tls_tcb * |
| 2624 | allocate_tls(Obj_Entry *objs) |
| 2625 | { |
| 2626 | Obj_Entry *obj; |
| 2627 | size_t data_size; |
| 2628 | size_t dtv_size; |
| 2629 | struct tls_tcb *tcb; |
| 2630 | Elf_Addr *dtv; |
| 2631 | Elf_Addr addr; |
| 2632 | |
| 2633 | /* |
| 2634 | * Allocate the new TCB. static TLS storage is placed just before the |
| 2635 | * TCB to support the %gs:OFFSET (negative offset) model. |
| 2636 | */ |
| 2637 | data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & |
| 2638 | ~RTLD_STATIC_TLS_ALIGN_MASK; |
| 2639 | tcb = malloc(data_size + sizeof(*tcb)); |
| 2640 | tcb = (void *)((char *)tcb + data_size); /* actual tcb location */ |
| 2641 | |
| 2642 | dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr); |
| 2643 | dtv = malloc(dtv_size); |
| 2644 | bzero(dtv, dtv_size); |
| 2645 | |
| 2646 | #ifdef RTLD_TCB_HAS_SELF_POINTER |
| 2647 | tcb->tcb_self = tcb; |
| 2648 | #endif |
| 2649 | tcb->tcb_dtv = dtv; |
| 2650 | tcb->tcb_pthread = NULL; |
| 2651 | |
| 2652 | dtv[0] = tls_dtv_generation; |
| 2653 | dtv[1] = tls_max_index; |
| 2654 | |
| 2655 | for (obj = objs; obj; obj = obj->next) { |
| 2656 | if (obj->tlsoffset) { |
| 2657 | addr = (Elf_Addr)tcb - obj->tlsoffset; |
| 2658 | memset((void *)(addr + obj->tlsinitsize), |
| 2659 | 0, obj->tlssize - obj->tlsinitsize); |
| 2660 | if (obj->tlsinit) |
| 2661 | memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize); |
| 2662 | dtv[obj->tlsindex + 1] = addr; |
| 2663 | } |
| 2664 | } |
| 2665 | return(tcb); |
| 2666 | } |
| 2667 | |
| 2668 | void |
| 2669 | free_tls(struct tls_tcb *tcb) |
| 2670 | { |
| 2671 | Elf_Addr *dtv; |
| 2672 | int dtv_size, i; |
| 2673 | Elf_Addr tls_start, tls_end; |
| 2674 | size_t data_size; |
| 2675 | |
| 2676 | data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) & |
| 2677 | ~RTLD_STATIC_TLS_ALIGN_MASK; |
| 2678 | dtv = tcb->tcb_dtv; |
| 2679 | dtv_size = dtv[1]; |
| 2680 | tls_end = (Elf_Addr)tcb; |
| 2681 | tls_start = (Elf_Addr)tcb - data_size; |
| 2682 | for (i = 0; i < dtv_size; i++) { |
| 2683 | if (dtv[i+2] != NULL && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) { |
| 2684 | free((void *)dtv[i+2]); |
| 2685 | } |
| 2686 | } |
| 2687 | free((void *)tls_start); |
| 2688 | } |
| 2689 | |
| 2690 | #else |
| 2691 | #error "Unsupported TLS layout" |
| 2692 | #endif |
| 2693 | |
| 2694 | /* |
| 2695 | * Allocate TLS block for module with given index. |
| 2696 | */ |
| 2697 | void * |
| 2698 | allocate_module_tls(int index) |
| 2699 | { |
| 2700 | Obj_Entry* obj; |
| 2701 | char* p; |
| 2702 | |
| 2703 | for (obj = obj_list; obj; obj = obj->next) { |
| 2704 | if (obj->tlsindex == index) |
| 2705 | break; |
| 2706 | } |
| 2707 | if (!obj) { |
| 2708 | _rtld_error("Can't find module with TLS index %d", index); |
| 2709 | die(); |
| 2710 | } |
| 2711 | |
| 2712 | p = malloc(obj->tlssize); |
| 2713 | memcpy(p, obj->tlsinit, obj->tlsinitsize); |
| 2714 | memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); |
| 2715 | |
| 2716 | return p; |
| 2717 | } |
| 2718 | |
| 2719 | bool |
| 2720 | allocate_tls_offset(Obj_Entry *obj) |
| 2721 | { |
| 2722 | size_t off; |
| 2723 | |
| 2724 | if (obj->tls_done) |
| 2725 | return true; |
| 2726 | |
| 2727 | if (obj->tlssize == 0) { |
| 2728 | obj->tls_done = true; |
| 2729 | return true; |
| 2730 | } |
| 2731 | |
| 2732 | if (obj->tlsindex == 1) |
| 2733 | off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign); |
| 2734 | else |
| 2735 | off = calculate_tls_offset(tls_last_offset, tls_last_size, |
| 2736 | obj->tlssize, obj->tlsalign); |
| 2737 | |
| 2738 | /* |
| 2739 | * If we have already fixed the size of the static TLS block, we |
| 2740 | * must stay within that size. When allocating the static TLS, we |
| 2741 | * leave a small amount of space spare to be used for dynamically |
| 2742 | * loading modules which use static TLS. |
| 2743 | */ |
| 2744 | if (tls_static_space) { |
| 2745 | if (calculate_tls_end(off, obj->tlssize) > tls_static_space) |
| 2746 | return false; |
| 2747 | } |
| 2748 | |
| 2749 | tls_last_offset = obj->tlsoffset = off; |
| 2750 | tls_last_size = obj->tlssize; |
| 2751 | obj->tls_done = true; |
| 2752 | |
| 2753 | return true; |
| 2754 | } |
| 2755 | |
| 2756 | void |
| 2757 | free_tls_offset(Obj_Entry *obj) |
| 2758 | { |
| 2759 | #ifdef RTLD_STATIC_TLS_VARIANT_II |
| 2760 | /* |
| 2761 | * If we were the last thing to allocate out of the static TLS |
| 2762 | * block, we give our space back to the 'allocator'. This is a |
| 2763 | * simplistic workaround to allow libGL.so.1 to be loaded and |
| 2764 | * unloaded multiple times. We only handle the Variant II |
| 2765 | * mechanism for now - this really needs a proper allocator. |
| 2766 | */ |
| 2767 | if (calculate_tls_end(obj->tlsoffset, obj->tlssize) |
| 2768 | == calculate_tls_end(tls_last_offset, tls_last_size)) { |
| 2769 | tls_last_offset -= obj->tlssize; |
| 2770 | tls_last_size = 0; |
| 2771 | } |
| 2772 | #endif |
| 2773 | } |
| 2774 | |
| 2775 | struct tls_tcb * |
| 2776 | _rtld_allocate_tls(void) |
| 2777 | { |
| 2778 | struct tls_tcb *new_tcb; |
| 2779 | |
| 2780 | wlock_acquire(); |
| 2781 | new_tcb = allocate_tls(obj_list); |
| 2782 | wlock_release(); |
| 2783 | |
| 2784 | return (new_tcb); |
| 2785 | } |
| 2786 | |
| 2787 | void |
| 2788 | _rtld_free_tls(struct tls_tcb *tcb) |
| 2789 | { |
| 2790 | wlock_acquire(); |
| 2791 | free_tls(tcb); |
| 2792 | wlock_release(); |
| 2793 | } |
| 2794 | |