1 /* Handle Darwin shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 2009-2016 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
30 #include "gdbthread.h"
35 #include "solib-svr4.h"
37 #include "bfd-target.h"
42 #include "mach-o/external.h"
44 struct gdb_dyld_image_info
46 /* Base address (which corresponds to the Mach-O header). */
47 CORE_ADDR mach_header;
48 /* Image file path. */
50 /* st.m_time of image file. */
54 /* Content of inferior dyld_all_image_infos structure.
55 See /usr/include/mach-o/dyld_images.h for the documentation. */
56 struct gdb_dyld_all_image_infos
60 /* Number of images. */
62 /* Image description. */
64 /* Notifier (function called when a library is added or removed). */
68 /* Current all_image_infos version. */
69 #define DYLD_VERSION_MIN 1
70 #define DYLD_VERSION_MAX 14
72 /* Per PSPACE specific data. */
75 /* Address of structure dyld_all_image_infos in inferior. */
76 CORE_ADDR all_image_addr;
78 /* Gdb copy of dyld_all_info_infos. */
79 struct gdb_dyld_all_image_infos all_image;
82 /* Per-program-space data key. */
83 static const struct program_space_data *solib_darwin_pspace_data;
86 darwin_pspace_data_cleanup (struct program_space *pspace, void *arg)
91 /* Get the current darwin data. If none is found yet, add it now. This
92 function always returns a valid object. */
94 static struct darwin_info *
95 get_darwin_info (void)
97 struct darwin_info *info;
99 info = (struct darwin_info *) program_space_data (current_program_space,
100 solib_darwin_pspace_data);
104 info = XCNEW (struct darwin_info);
105 set_program_space_data (current_program_space,
106 solib_darwin_pspace_data, info);
110 /* Return non-zero if the version in dyld_all_image is known. */
113 darwin_dyld_version_ok (const struct darwin_info *info)
115 return info->all_image.version >= DYLD_VERSION_MIN
116 && info->all_image.version <= DYLD_VERSION_MAX;
119 /* Read dyld_all_image from inferior. */
122 darwin_load_image_infos (struct darwin_info *info)
125 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
126 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
129 /* If the structure address is not known, don't continue. */
130 if (info->all_image_addr == 0)
133 /* The structure has 4 fields: version (4 bytes), count (4 bytes),
134 info (pointer) and notifier (pointer). */
135 len = 4 + 4 + 2 * TYPE_LENGTH (ptr_type);
136 gdb_assert (len <= sizeof (buf));
137 memset (&info->all_image, 0, sizeof (info->all_image));
139 /* Read structure raw bytes from target. */
140 if (target_read_memory (info->all_image_addr, buf, len))
143 /* Extract the fields. */
144 info->all_image.version = extract_unsigned_integer (buf, 4, byte_order);
145 if (!darwin_dyld_version_ok (info))
148 info->all_image.count = extract_unsigned_integer (buf + 4, 4, byte_order);
149 info->all_image.info = extract_typed_address (buf + 8, ptr_type);
150 info->all_image.notifier = extract_typed_address
151 (buf + 8 + TYPE_LENGTH (ptr_type), ptr_type);
154 /* Link map info to include in an allocated so_list entry. */
158 /* The target location of lm. */
162 struct darwin_so_list
166 /* Darwin specific data. */
170 /* Lookup the value for a specific symbol. */
173 lookup_symbol_from_bfd (bfd *abfd, char *symname)
176 asymbol **symbol_table;
177 unsigned int number_of_symbols;
179 CORE_ADDR symaddr = 0;
181 storage_needed = bfd_get_symtab_upper_bound (abfd);
183 if (storage_needed <= 0)
186 symbol_table = (asymbol **) xmalloc (storage_needed);
187 number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
189 for (i = 0; i < number_of_symbols; i++)
191 asymbol *sym = symbol_table[i];
193 if (strcmp (sym->name, symname) == 0
194 && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
196 /* BFD symbols are section relative. */
197 symaddr = sym->value + sym->section->vma;
201 xfree (symbol_table);
206 /* Return program interpreter string. */
209 find_program_interpreter (void)
213 /* If we have an exec_bfd, get the interpreter from the load commands. */
216 bfd_mach_o_load_command *cmd;
218 if (bfd_mach_o_lookup_command (exec_bfd,
219 BFD_MACH_O_LC_LOAD_DYLINKER, &cmd) == 1)
220 return cmd->command.dylinker.name_str;
223 /* If we didn't find it, read from memory.
228 /* Not used. I don't see how the main symbol file can be found: the
229 interpreter name is needed and it is known from the executable file.
230 Note that darwin-nat.c implements pid_to_exec_file. */
233 open_symbol_file_object (void *from_ttyp)
238 /* Build a list of currently loaded shared objects. See solib-svr4.c. */
240 static struct so_list *
241 darwin_current_sos (void)
243 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
244 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
245 int ptr_len = TYPE_LENGTH (ptr_type);
246 unsigned int image_info_size;
247 struct so_list *head = NULL;
248 struct so_list *tail = NULL;
250 struct darwin_info *info = get_darwin_info ();
252 /* Be sure image infos are loaded. */
253 darwin_load_image_infos (info);
255 if (!darwin_dyld_version_ok (info))
258 image_info_size = ptr_len * 3;
260 /* Read infos for each solib.
261 The first entry was rumored to be the executable itself, but this is not
262 true when a large number of shared libraries are used (table expanded ?).
263 We now check all entries, but discard executable images. */
264 for (i = 0; i < info->all_image.count; i++)
266 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
267 gdb_byte buf[image_info_size];
270 struct mach_o_header_external hdr;
271 unsigned long hdr_val;
274 struct darwin_so_list *dnew;
275 struct so_list *newobj;
276 struct cleanup *old_chain;
278 /* Read image info from inferior. */
279 if (target_read_memory (iinfo, buf, image_info_size))
282 load_addr = extract_typed_address (buf, ptr_type);
283 path_addr = extract_typed_address (buf + ptr_len, ptr_type);
285 /* Read Mach-O header from memory. */
286 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
288 /* Discard wrong magic numbers. Shouldn't happen. */
289 hdr_val = extract_unsigned_integer
290 (hdr.magic, sizeof (hdr.magic), byte_order);
291 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
293 /* Discard executable. Should happen only once. */
294 hdr_val = extract_unsigned_integer
295 (hdr.filetype, sizeof (hdr.filetype), byte_order);
296 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
299 target_read_string (path_addr, &file_path,
300 SO_NAME_MAX_PATH_SIZE - 1, &errcode);
304 /* Create and fill the new so_list element. */
305 dnew = XCNEW (struct darwin_so_list);
307 old_chain = make_cleanup (xfree, dnew);
309 newobj->lm_info = &dnew->li;
311 strncpy (newobj->so_name, file_path, SO_NAME_MAX_PATH_SIZE - 1);
312 newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
313 strcpy (newobj->so_original_name, newobj->so_name);
315 newobj->lm_info->lm_addr = load_addr;
323 discard_cleanups (old_chain);
329 /* Check LOAD_ADDR points to a Mach-O executable header. Return LOAD_ADDR
330 in case of success, 0 in case of failure. */
333 darwin_validate_exec_header (CORE_ADDR load_addr)
335 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
336 struct mach_o_header_external hdr;
337 unsigned long hdr_val;
339 /* Read Mach-O header from memory. */
340 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
343 /* Discard wrong magic numbers. Shouldn't happen. */
344 hdr_val = extract_unsigned_integer
345 (hdr.magic, sizeof (hdr.magic), byte_order);
346 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
349 /* Check executable. */
350 hdr_val = extract_unsigned_integer
351 (hdr.filetype, sizeof (hdr.filetype), byte_order);
352 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
358 /* Get the load address of the executable using dyld list of images.
359 We assume that the dyld info are correct (which is wrong if the target
360 is stopped at the first instruction). */
363 darwin_read_exec_load_addr_from_dyld (struct darwin_info *info)
365 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
366 int ptr_len = TYPE_LENGTH (ptr_type);
367 unsigned int image_info_size = ptr_len * 3;
370 /* Read infos for each solib. One of them should be the executable. */
371 for (i = 0; i < info->all_image.count; i++)
373 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
374 gdb_byte buf[image_info_size];
377 /* Read image info from inferior. */
378 if (target_read_memory (iinfo, buf, image_info_size))
381 load_addr = extract_typed_address (buf, ptr_type);
382 if (darwin_validate_exec_header (load_addr) == load_addr)
389 /* Get the load address of the executable when the PC is at the dyld
390 entry point using parameter passed by the kernel (at SP). */
393 darwin_read_exec_load_addr_at_init (struct darwin_info *info)
395 struct gdbarch *gdbarch = target_gdbarch ();
396 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
397 int addr_size = gdbarch_addr_bit (gdbarch) / 8;
398 ULONGEST load_ptr_addr;
403 if (regcache_cooked_read_unsigned (get_current_regcache (),
404 gdbarch_sp_regnum (gdbarch),
405 &load_ptr_addr) != REG_VALID)
408 /* Read value at SP (image load address). */
409 if (target_read_memory (load_ptr_addr, buf, addr_size))
412 load_addr = extract_unsigned_integer (buf, addr_size, byte_order);
414 return darwin_validate_exec_header (load_addr);
417 /* Return 1 if PC lies in the dynamic symbol resolution code of the
421 darwin_in_dynsym_resolve_code (CORE_ADDR pc)
426 /* A wrapper for bfd_mach_o_fat_extract that handles reference
427 counting properly. This will either return NULL, or return a new
428 reference to a BFD. */
431 gdb_bfd_mach_o_fat_extract (bfd *abfd, bfd_format format,
432 const bfd_arch_info_type *arch)
434 bfd *result = bfd_mach_o_fat_extract (abfd, format, arch);
440 gdb_bfd_ref (result);
442 gdb_bfd_mark_parent (result, abfd);
447 /* Extract dyld_all_image_addr when the process was just created, assuming the
448 current PC is at the entry of the dynamic linker. */
451 darwin_solib_get_all_image_info_addr_at_init (struct darwin_info *info)
454 CORE_ADDR load_addr = 0;
455 bfd *dyld_bfd = NULL;
456 struct cleanup *cleanup;
458 /* This method doesn't work with an attached process. */
459 if (current_inferior ()->attach_flag)
462 /* Find the program interpreter. */
463 interp_name = find_program_interpreter ();
467 cleanup = make_cleanup (null_cleanup, NULL);
469 /* Create a bfd for the interpreter. */
470 dyld_bfd = gdb_bfd_open (interp_name, gnutarget, -1);
475 make_cleanup_bfd_unref (dyld_bfd);
476 sub = gdb_bfd_mach_o_fat_extract
477 (dyld_bfd, bfd_object, gdbarch_bfd_arch_info (target_gdbarch ()));
481 make_cleanup_bfd_unref (sub);
488 do_cleanups (cleanup);
492 /* We find the dynamic linker's base address by examining
493 the current pc (which should point at the entry point for the
494 dynamic linker) and subtracting the offset of the entry point. */
495 load_addr = (regcache_read_pc (get_current_regcache ())
496 - bfd_get_start_address (dyld_bfd));
498 /* Now try to set a breakpoint in the dynamic linker. */
499 info->all_image_addr =
500 lookup_symbol_from_bfd (dyld_bfd, "_dyld_all_image_infos");
502 do_cleanups (cleanup);
504 if (info->all_image_addr == 0)
507 info->all_image_addr += load_addr;
510 /* Extract dyld_all_image_addr reading it from
511 TARGET_OBJECT_DARWIN_DYLD_INFO. */
514 darwin_solib_read_all_image_info_addr (struct darwin_info *info)
518 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
521 if (TYPE_LENGTH (ptr_type) > sizeof (buf))
524 len = target_read (¤t_target, TARGET_OBJECT_DARWIN_DYLD_INFO, NULL,
525 buf, 0, TYPE_LENGTH (ptr_type));
529 /* The use of BIG endian is intended, as BUF is a raw stream of bytes. This
530 makes the support of remote protocol easier. */
531 info->all_image_addr = extract_unsigned_integer (buf, len, BFD_ENDIAN_BIG);
534 /* Shared library startup support. See documentation in solib-svr4.c. */
537 darwin_solib_create_inferior_hook (int from_tty)
539 struct darwin_info *info = get_darwin_info ();
542 info->all_image_addr = 0;
544 darwin_solib_read_all_image_info_addr (info);
546 if (info->all_image_addr == 0)
547 darwin_solib_get_all_image_info_addr_at_init (info);
549 if (info->all_image_addr == 0)
552 darwin_load_image_infos (info);
554 if (!darwin_dyld_version_ok (info))
556 warning (_("unhandled dyld version (%d)"), info->all_image.version);
560 /* Add the breakpoint which is hit by dyld when the list of solib is
562 create_solib_event_breakpoint (target_gdbarch (), info->all_image.notifier);
564 if (info->all_image.count != 0)
566 /* Possible relocate the main executable (PIE). */
567 load_addr = darwin_read_exec_load_addr_from_dyld (info);
572 Do not break on the notifier if dyld is not initialized (deduced from
573 count == 0). In that case, dyld hasn't relocated itself and the
574 notifier may point to a wrong address. */
576 load_addr = darwin_read_exec_load_addr_at_init (info);
579 if (load_addr != 0 && symfile_objfile != NULL)
583 /* Find the base address of the executable. */
584 vmaddr = bfd_mach_o_get_base_address (exec_bfd);
587 if (vmaddr != load_addr)
588 objfile_rebase (symfile_objfile, load_addr - vmaddr);
593 darwin_clear_solib (void)
595 struct darwin_info *info = get_darwin_info ();
597 info->all_image_addr = 0;
598 info->all_image.version = 0;
602 darwin_free_so (struct so_list *so)
606 /* The section table is built from bfd sections using bfd VMAs.
607 Relocate these VMAs according to solib info. */
610 darwin_relocate_section_addresses (struct so_list *so,
611 struct target_section *sec)
613 sec->addr += so->lm_info->lm_addr;
614 sec->endaddr += so->lm_info->lm_addr;
616 /* Best effort to set addr_high/addr_low. This is used only by
617 'info sharedlibary'. */
618 if (so->addr_high == 0)
620 so->addr_low = sec->addr;
621 so->addr_high = sec->endaddr;
623 if (sec->endaddr > so->addr_high)
624 so->addr_high = sec->endaddr;
625 if (sec->addr < so->addr_low)
626 so->addr_low = sec->addr;
629 static struct block_symbol
630 darwin_lookup_lib_symbol (struct objfile *objfile,
632 const domain_enum domain)
634 return (struct block_symbol) {NULL, NULL};
638 darwin_bfd_open (char *pathname)
640 char *found_pathname;
645 /* Search for shared library file. */
646 found_pathname = solib_find (pathname, &found_file);
647 if (found_pathname == NULL)
648 perror_with_name (pathname);
650 /* Open bfd for shared library. */
651 abfd = solib_bfd_fopen (found_pathname, found_file);
653 res = gdb_bfd_mach_o_fat_extract (abfd, bfd_object,
654 gdbarch_bfd_arch_info (target_gdbarch ()));
657 make_cleanup_bfd_unref (abfd);
658 error (_("`%s': not a shared-library: %s"),
659 bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));
662 /* The current filename for fat-binary BFDs is a name generated
663 by BFD, usually a string containing the name of the architecture.
664 Reset its value to the actual filename. */
665 xfree (bfd_get_filename (res));
666 res->filename = xstrdup (pathname);
668 gdb_bfd_unref (abfd);
672 struct target_so_ops darwin_so_ops;
674 /* -Wmissing-prototypes */
675 extern initialize_file_ftype _initialize_darwin_solib;
678 _initialize_darwin_solib (void)
680 solib_darwin_pspace_data
681 = register_program_space_data_with_cleanup (NULL,
682 darwin_pspace_data_cleanup);
684 darwin_so_ops.relocate_section_addresses = darwin_relocate_section_addresses;
685 darwin_so_ops.free_so = darwin_free_so;
686 darwin_so_ops.clear_solib = darwin_clear_solib;
687 darwin_so_ops.solib_create_inferior_hook = darwin_solib_create_inferior_hook;
688 darwin_so_ops.current_sos = darwin_current_sos;
689 darwin_so_ops.open_symbol_file_object = open_symbol_file_object;
690 darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;
691 darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
692 darwin_so_ops.bfd_open = darwin_bfd_open;