| 1 | /* Handle Darwin shared libraries for GDB, the GNU Debugger. |
| 2 | |
| 3 | Copyright (C) 2009-2012 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | |
| 22 | #include "symtab.h" |
| 23 | #include "bfd.h" |
| 24 | #include "symfile.h" |
| 25 | #include "objfiles.h" |
| 26 | #include "gdbcore.h" |
| 27 | #include "target.h" |
| 28 | #include "inferior.h" |
| 29 | #include "regcache.h" |
| 30 | #include "gdbthread.h" |
| 31 | |
| 32 | #include "gdb_assert.h" |
| 33 | |
| 34 | #include "solist.h" |
| 35 | #include "solib.h" |
| 36 | #include "solib-svr4.h" |
| 37 | |
| 38 | #include "bfd-target.h" |
| 39 | #include "elf-bfd.h" |
| 40 | #include "exec.h" |
| 41 | #include "auxv.h" |
| 42 | #include "exceptions.h" |
| 43 | #include "mach-o.h" |
| 44 | #include "mach-o/external.h" |
| 45 | |
| 46 | struct gdb_dyld_image_info |
| 47 | { |
| 48 | /* Base address (which corresponds to the Mach-O header). */ |
| 49 | CORE_ADDR mach_header; |
| 50 | /* Image file path. */ |
| 51 | CORE_ADDR file_path; |
| 52 | /* st.m_time of image file. */ |
| 53 | unsigned long mtime; |
| 54 | }; |
| 55 | |
| 56 | /* Content of inferior dyld_all_image_infos structure. |
| 57 | See /usr/include/mach-o/dyld_images.h for the documentation. */ |
| 58 | struct gdb_dyld_all_image_infos |
| 59 | { |
| 60 | /* Version (1). */ |
| 61 | unsigned int version; |
| 62 | /* Number of images. */ |
| 63 | unsigned int count; |
| 64 | /* Image description. */ |
| 65 | CORE_ADDR info; |
| 66 | /* Notifier (function called when a library is added or removed). */ |
| 67 | CORE_ADDR notifier; |
| 68 | }; |
| 69 | |
| 70 | /* Current all_image_infos version. */ |
| 71 | #define DYLD_VERSION_MIN 1 |
| 72 | #define DYLD_VERSION_MAX 12 |
| 73 | |
| 74 | /* Address of structure dyld_all_image_infos in inferior. */ |
| 75 | static CORE_ADDR dyld_all_image_addr; |
| 76 | |
| 77 | /* Gdb copy of dyld_all_info_infos. */ |
| 78 | static struct gdb_dyld_all_image_infos dyld_all_image; |
| 79 | |
| 80 | /* Return non-zero if the version in dyld_all_image is known. */ |
| 81 | |
| 82 | static int |
| 83 | darwin_dyld_version_ok (void) |
| 84 | { |
| 85 | return dyld_all_image.version >= DYLD_VERSION_MIN |
| 86 | && dyld_all_image.version <= DYLD_VERSION_MAX; |
| 87 | } |
| 88 | |
| 89 | /* Read dyld_all_image from inferior. */ |
| 90 | |
| 91 | static void |
| 92 | darwin_load_image_infos (void) |
| 93 | { |
| 94 | gdb_byte buf[24]; |
| 95 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 96 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 97 | int len; |
| 98 | |
| 99 | /* If the structure address is not known, don't continue. */ |
| 100 | if (dyld_all_image_addr == 0) |
| 101 | return; |
| 102 | |
| 103 | /* The structure has 4 fields: version (4 bytes), count (4 bytes), |
| 104 | info (pointer) and notifier (pointer). */ |
| 105 | len = 4 + 4 + 2 * ptr_type->length; |
| 106 | gdb_assert (len <= sizeof (buf)); |
| 107 | memset (&dyld_all_image, 0, sizeof (dyld_all_image)); |
| 108 | |
| 109 | /* Read structure raw bytes from target. */ |
| 110 | if (target_read_memory (dyld_all_image_addr, buf, len)) |
| 111 | return; |
| 112 | |
| 113 | /* Extract the fields. */ |
| 114 | dyld_all_image.version = extract_unsigned_integer (buf, 4, byte_order); |
| 115 | if (!darwin_dyld_version_ok ()) |
| 116 | return; |
| 117 | |
| 118 | dyld_all_image.count = extract_unsigned_integer (buf + 4, 4, byte_order); |
| 119 | dyld_all_image.info = extract_typed_address (buf + 8, ptr_type); |
| 120 | dyld_all_image.notifier = extract_typed_address |
| 121 | (buf + 8 + ptr_type->length, ptr_type); |
| 122 | } |
| 123 | |
| 124 | /* Link map info to include in an allocated so_list entry. */ |
| 125 | |
| 126 | struct lm_info |
| 127 | { |
| 128 | /* The target location of lm. */ |
| 129 | CORE_ADDR lm_addr; |
| 130 | }; |
| 131 | |
| 132 | struct darwin_so_list |
| 133 | { |
| 134 | /* Common field. */ |
| 135 | struct so_list sl; |
| 136 | /* Darwin specific data. */ |
| 137 | struct lm_info li; |
| 138 | }; |
| 139 | |
| 140 | /* Lookup the value for a specific symbol. */ |
| 141 | |
| 142 | static CORE_ADDR |
| 143 | lookup_symbol_from_bfd (bfd *abfd, char *symname) |
| 144 | { |
| 145 | long storage_needed; |
| 146 | asymbol **symbol_table; |
| 147 | unsigned int number_of_symbols; |
| 148 | unsigned int i; |
| 149 | CORE_ADDR symaddr = 0; |
| 150 | |
| 151 | storage_needed = bfd_get_symtab_upper_bound (abfd); |
| 152 | |
| 153 | if (storage_needed <= 0) |
| 154 | return 0; |
| 155 | |
| 156 | symbol_table = (asymbol **) xmalloc (storage_needed); |
| 157 | number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
| 158 | |
| 159 | for (i = 0; i < number_of_symbols; i++) |
| 160 | { |
| 161 | asymbol *sym = symbol_table[i]; |
| 162 | |
| 163 | if (strcmp (sym->name, symname) == 0 |
| 164 | && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0) |
| 165 | { |
| 166 | /* BFD symbols are section relative. */ |
| 167 | symaddr = sym->value + sym->section->vma; |
| 168 | break; |
| 169 | } |
| 170 | } |
| 171 | xfree (symbol_table); |
| 172 | |
| 173 | return symaddr; |
| 174 | } |
| 175 | |
| 176 | /* Return program interpreter string. */ |
| 177 | |
| 178 | static gdb_byte * |
| 179 | find_program_interpreter (void) |
| 180 | { |
| 181 | gdb_byte *buf = NULL; |
| 182 | |
| 183 | /* If we have an exec_bfd, get the interpreter from the load commands. */ |
| 184 | if (exec_bfd) |
| 185 | { |
| 186 | bfd_mach_o_load_command *cmd; |
| 187 | |
| 188 | if (bfd_mach_o_lookup_command (exec_bfd, |
| 189 | BFD_MACH_O_LC_LOAD_DYLINKER, &cmd) == 1) |
| 190 | return cmd->command.dylinker.name_str; |
| 191 | } |
| 192 | |
| 193 | /* If we didn't find it, read from memory. |
| 194 | FIXME: todo. */ |
| 195 | return buf; |
| 196 | } |
| 197 | |
| 198 | /* Not used. I don't see how the main symbol file can be found: the |
| 199 | interpreter name is needed and it is known from the executable file. |
| 200 | Note that darwin-nat.c implements pid_to_exec_file. */ |
| 201 | |
| 202 | static int |
| 203 | open_symbol_file_object (void *from_ttyp) |
| 204 | { |
| 205 | return 0; |
| 206 | } |
| 207 | |
| 208 | /* Build a list of currently loaded shared objects. See solib-svr4.c. */ |
| 209 | |
| 210 | static struct so_list * |
| 211 | darwin_current_sos (void) |
| 212 | { |
| 213 | struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr; |
| 214 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 215 | int ptr_len = TYPE_LENGTH (ptr_type); |
| 216 | unsigned int image_info_size; |
| 217 | CORE_ADDR lm; |
| 218 | struct so_list *head = NULL; |
| 219 | struct so_list *tail = NULL; |
| 220 | int i; |
| 221 | |
| 222 | /* Be sure image infos are loaded. */ |
| 223 | darwin_load_image_infos (); |
| 224 | |
| 225 | if (!darwin_dyld_version_ok ()) |
| 226 | return NULL; |
| 227 | |
| 228 | image_info_size = ptr_len * 3; |
| 229 | |
| 230 | /* Read infos for each solib. |
| 231 | The first entry was rumored to be the executable itself, but this is not |
| 232 | true when a large number of shared libraries are used (table expanded ?). |
| 233 | We now check all entries, but discard executable images. */ |
| 234 | for (i = 0; i < dyld_all_image.count; i++) |
| 235 | { |
| 236 | CORE_ADDR info = dyld_all_image.info + i * image_info_size; |
| 237 | char buf[image_info_size]; |
| 238 | CORE_ADDR load_addr; |
| 239 | CORE_ADDR path_addr; |
| 240 | struct mach_o_header_external hdr; |
| 241 | unsigned long hdr_val; |
| 242 | char *file_path; |
| 243 | int errcode; |
| 244 | struct darwin_so_list *dnew; |
| 245 | struct so_list *new; |
| 246 | struct cleanup *old_chain; |
| 247 | |
| 248 | /* Read image info from inferior. */ |
| 249 | if (target_read_memory (info, buf, image_info_size)) |
| 250 | break; |
| 251 | |
| 252 | load_addr = extract_typed_address (buf, ptr_type); |
| 253 | path_addr = extract_typed_address (buf + ptr_len, ptr_type); |
| 254 | |
| 255 | /* Read Mach-O header from memory. */ |
| 256 | if (target_read_memory (load_addr, (char *) &hdr, sizeof (hdr) - 4)) |
| 257 | break; |
| 258 | /* Discard wrong magic numbers. Shouldn't happen. */ |
| 259 | hdr_val = extract_unsigned_integer |
| 260 | (hdr.magic, sizeof (hdr.magic), byte_order); |
| 261 | if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64) |
| 262 | continue; |
| 263 | /* Discard executable. Should happen only once. */ |
| 264 | hdr_val = extract_unsigned_integer |
| 265 | (hdr.filetype, sizeof (hdr.filetype), byte_order); |
| 266 | if (hdr_val == BFD_MACH_O_MH_EXECUTE) |
| 267 | continue; |
| 268 | |
| 269 | target_read_string (path_addr, &file_path, |
| 270 | SO_NAME_MAX_PATH_SIZE - 1, &errcode); |
| 271 | if (errcode) |
| 272 | break; |
| 273 | |
| 274 | /* Create and fill the new so_list element. */ |
| 275 | dnew = XZALLOC (struct darwin_so_list); |
| 276 | new = &dnew->sl; |
| 277 | old_chain = make_cleanup (xfree, dnew); |
| 278 | |
| 279 | new->lm_info = &dnew->li; |
| 280 | |
| 281 | strncpy (new->so_name, file_path, SO_NAME_MAX_PATH_SIZE - 1); |
| 282 | new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| 283 | strcpy (new->so_original_name, new->so_name); |
| 284 | xfree (file_path); |
| 285 | new->lm_info->lm_addr = load_addr; |
| 286 | |
| 287 | if (head == NULL) |
| 288 | head = new; |
| 289 | else |
| 290 | tail->next = new; |
| 291 | tail = new; |
| 292 | |
| 293 | discard_cleanups (old_chain); |
| 294 | } |
| 295 | |
| 296 | return head; |
| 297 | } |
| 298 | |
| 299 | /* Return 1 if PC lies in the dynamic symbol resolution code of the |
| 300 | run time loader. */ |
| 301 | |
| 302 | int |
| 303 | darwin_in_dynsym_resolve_code (CORE_ADDR pc) |
| 304 | { |
| 305 | return 0; |
| 306 | } |
| 307 | |
| 308 | |
| 309 | /* No special symbol handling. */ |
| 310 | |
| 311 | static void |
| 312 | darwin_special_symbol_handling (void) |
| 313 | { |
| 314 | } |
| 315 | |
| 316 | /* Extract dyld_all_image_addr when the process was just created, assuming the |
| 317 | current PC is at the entry of the dynamic linker. */ |
| 318 | |
| 319 | static void |
| 320 | darwin_solib_get_all_image_info_addr_at_init (void) |
| 321 | { |
| 322 | gdb_byte *interp_name; |
| 323 | CORE_ADDR load_addr = 0; |
| 324 | bfd *dyld_bfd = NULL; |
| 325 | |
| 326 | /* This method doesn't work with an attached process. */ |
| 327 | if (current_inferior ()->attach_flag) |
| 328 | return; |
| 329 | |
| 330 | /* Find the program interpreter. */ |
| 331 | interp_name = find_program_interpreter (); |
| 332 | if (!interp_name) |
| 333 | return; |
| 334 | |
| 335 | /* Create a bfd for the interpreter. */ |
| 336 | dyld_bfd = bfd_openr (interp_name, gnutarget); |
| 337 | if (dyld_bfd) |
| 338 | { |
| 339 | bfd *sub; |
| 340 | |
| 341 | sub = bfd_mach_o_fat_extract (dyld_bfd, bfd_object, |
| 342 | gdbarch_bfd_arch_info (target_gdbarch)); |
| 343 | if (sub) |
| 344 | dyld_bfd = sub; |
| 345 | else |
| 346 | { |
| 347 | bfd_close (dyld_bfd); |
| 348 | dyld_bfd = NULL; |
| 349 | } |
| 350 | } |
| 351 | if (!dyld_bfd) |
| 352 | return; |
| 353 | |
| 354 | /* We find the dynamic linker's base address by examining |
| 355 | the current pc (which should point at the entry point for the |
| 356 | dynamic linker) and subtracting the offset of the entry point. */ |
| 357 | load_addr = (regcache_read_pc (get_current_regcache ()) |
| 358 | - bfd_get_start_address (dyld_bfd)); |
| 359 | |
| 360 | /* Now try to set a breakpoint in the dynamic linker. */ |
| 361 | dyld_all_image_addr = |
| 362 | lookup_symbol_from_bfd (dyld_bfd, "_dyld_all_image_infos"); |
| 363 | |
| 364 | bfd_close (dyld_bfd); |
| 365 | |
| 366 | if (dyld_all_image_addr == 0) |
| 367 | return; |
| 368 | |
| 369 | dyld_all_image_addr += load_addr; |
| 370 | } |
| 371 | |
| 372 | /* Extract dyld_all_image_addr reading it from |
| 373 | TARGET_OBJECT_DARWIN_DYLD_INFO. */ |
| 374 | |
| 375 | static void |
| 376 | darwin_solib_read_all_image_info_addr (void) |
| 377 | { |
| 378 | gdb_byte buf[8 + 8 + 4]; |
| 379 | LONGEST len; |
| 380 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch); |
| 381 | |
| 382 | len = target_read (¤t_target, TARGET_OBJECT_DARWIN_DYLD_INFO, NULL, |
| 383 | buf, 0, sizeof (buf)); |
| 384 | if (len != sizeof (buf)) |
| 385 | return; |
| 386 | |
| 387 | dyld_all_image_addr = extract_unsigned_integer (buf, 8, byte_order); |
| 388 | } |
| 389 | |
| 390 | /* Shared library startup support. See documentation in solib-svr4.c. */ |
| 391 | |
| 392 | static void |
| 393 | darwin_solib_create_inferior_hook (int from_tty) |
| 394 | { |
| 395 | dyld_all_image_addr = 0; |
| 396 | |
| 397 | darwin_solib_read_all_image_info_addr (); |
| 398 | |
| 399 | if (dyld_all_image_addr == 0) |
| 400 | darwin_solib_get_all_image_info_addr_at_init (); |
| 401 | |
| 402 | if (dyld_all_image_addr == 0) |
| 403 | return; |
| 404 | |
| 405 | darwin_load_image_infos (); |
| 406 | |
| 407 | if (darwin_dyld_version_ok ()) |
| 408 | create_solib_event_breakpoint (target_gdbarch, dyld_all_image.notifier); |
| 409 | } |
| 410 | |
| 411 | static void |
| 412 | darwin_clear_solib (void) |
| 413 | { |
| 414 | dyld_all_image_addr = 0; |
| 415 | dyld_all_image.version = 0; |
| 416 | } |
| 417 | |
| 418 | static void |
| 419 | darwin_free_so (struct so_list *so) |
| 420 | { |
| 421 | } |
| 422 | |
| 423 | /* The section table is built from bfd sections using bfd VMAs. |
| 424 | Relocate these VMAs according to solib info. */ |
| 425 | |
| 426 | static void |
| 427 | darwin_relocate_section_addresses (struct so_list *so, |
| 428 | struct target_section *sec) |
| 429 | { |
| 430 | sec->addr += so->lm_info->lm_addr; |
| 431 | sec->endaddr += so->lm_info->lm_addr; |
| 432 | |
| 433 | /* Best effort to set addr_high/addr_low. This is used only by |
| 434 | 'info sharedlibary'. */ |
| 435 | if (so->addr_high == 0) |
| 436 | { |
| 437 | so->addr_low = sec->addr; |
| 438 | so->addr_high = sec->endaddr; |
| 439 | } |
| 440 | if (sec->endaddr > so->addr_high) |
| 441 | so->addr_high = sec->endaddr; |
| 442 | if (sec->addr < so->addr_low) |
| 443 | so->addr_low = sec->addr; |
| 444 | } |
| 445 | \f |
| 446 | static struct symbol * |
| 447 | darwin_lookup_lib_symbol (const struct objfile *objfile, |
| 448 | const char *name, |
| 449 | const domain_enum domain) |
| 450 | { |
| 451 | return NULL; |
| 452 | } |
| 453 | |
| 454 | static bfd * |
| 455 | darwin_bfd_open (char *pathname) |
| 456 | { |
| 457 | char *found_pathname; |
| 458 | int found_file; |
| 459 | bfd *abfd; |
| 460 | bfd *res; |
| 461 | |
| 462 | /* Search for shared library file. */ |
| 463 | found_pathname = solib_find (pathname, &found_file); |
| 464 | if (found_pathname == NULL) |
| 465 | perror_with_name (pathname); |
| 466 | |
| 467 | /* Open bfd for shared library. */ |
| 468 | abfd = solib_bfd_fopen (found_pathname, found_file); |
| 469 | |
| 470 | res = bfd_mach_o_fat_extract (abfd, bfd_object, |
| 471 | gdbarch_bfd_arch_info (target_gdbarch)); |
| 472 | if (!res) |
| 473 | { |
| 474 | bfd_close (abfd); |
| 475 | make_cleanup (xfree, found_pathname); |
| 476 | error (_("`%s': not a shared-library: %s"), |
| 477 | found_pathname, bfd_errmsg (bfd_get_error ())); |
| 478 | } |
| 479 | |
| 480 | /* Make sure that the filename is malloc'ed. The current filename |
| 481 | for fat-binaries BFDs is a name that was generated by BFD, usually |
| 482 | a static string containing the name of the architecture. */ |
| 483 | res->filename = xstrdup (pathname); |
| 484 | |
| 485 | return res; |
| 486 | } |
| 487 | |
| 488 | struct target_so_ops darwin_so_ops; |
| 489 | |
| 490 | void |
| 491 | _initialize_darwin_solib (void) |
| 492 | { |
| 493 | darwin_so_ops.relocate_section_addresses = darwin_relocate_section_addresses; |
| 494 | darwin_so_ops.free_so = darwin_free_so; |
| 495 | darwin_so_ops.clear_solib = darwin_clear_solib; |
| 496 | darwin_so_ops.solib_create_inferior_hook = darwin_solib_create_inferior_hook; |
| 497 | darwin_so_ops.special_symbol_handling = darwin_special_symbol_handling; |
| 498 | darwin_so_ops.current_sos = darwin_current_sos; |
| 499 | darwin_so_ops.open_symbol_file_object = open_symbol_file_object; |
| 500 | darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code; |
| 501 | darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol; |
| 502 | darwin_so_ops.bfd_open = darwin_bfd_open; |
| 503 | } |