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 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
367 int ptr_len = TYPE_LENGTH (ptr_type);
368 unsigned int image_info_size = ptr_len * 3;
371 /* Read infos for each solib. One of them should be the executable. */
372 for (i = 0; i < info->all_image.count; i++)
374 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
375 gdb_byte buf[image_info_size];
378 /* Read image info from inferior. */
379 if (target_read_memory (iinfo, buf, image_info_size))
382 load_addr = extract_typed_address (buf, ptr_type);
383 if (darwin_validate_exec_header (load_addr) == load_addr)
390 /* Get the load address of the executable when the PC is at the dyld
391 entry point using parameter passed by the kernel (at SP). */
394 darwin_read_exec_load_addr_at_init (struct darwin_info *info)
396 struct gdbarch *gdbarch = target_gdbarch ();
397 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
398 int addr_size = gdbarch_addr_bit (gdbarch) / 8;
399 ULONGEST load_ptr_addr;
404 if (regcache_cooked_read_unsigned (get_current_regcache (),
405 gdbarch_sp_regnum (gdbarch),
406 &load_ptr_addr) != REG_VALID)
409 /* Read value at SP (image load address). */
410 if (target_read_memory (load_ptr_addr, buf, addr_size))
413 load_addr = extract_unsigned_integer (buf, addr_size, byte_order);
415 return darwin_validate_exec_header (load_addr);
418 /* Return 1 if PC lies in the dynamic symbol resolution code of the
422 darwin_in_dynsym_resolve_code (CORE_ADDR pc)
428 /* No special symbol handling. */
431 darwin_special_symbol_handling (void)
435 /* A wrapper for bfd_mach_o_fat_extract that handles reference
436 counting properly. This will either return NULL, or return a new
437 reference to a BFD. */
440 gdb_bfd_mach_o_fat_extract (bfd *abfd, bfd_format format,
441 const bfd_arch_info_type *arch)
443 bfd *result = bfd_mach_o_fat_extract (abfd, format, arch);
449 gdb_bfd_ref (result);
451 gdb_bfd_mark_parent (result, abfd);
456 /* Extract dyld_all_image_addr when the process was just created, assuming the
457 current PC is at the entry of the dynamic linker. */
460 darwin_solib_get_all_image_info_addr_at_init (struct darwin_info *info)
463 CORE_ADDR load_addr = 0;
464 bfd *dyld_bfd = NULL;
465 struct cleanup *cleanup;
467 /* This method doesn't work with an attached process. */
468 if (current_inferior ()->attach_flag)
471 /* Find the program interpreter. */
472 interp_name = find_program_interpreter ();
476 cleanup = make_cleanup (null_cleanup, NULL);
478 /* Create a bfd for the interpreter. */
479 dyld_bfd = gdb_bfd_open (interp_name, gnutarget, -1);
484 make_cleanup_bfd_unref (dyld_bfd);
485 sub = gdb_bfd_mach_o_fat_extract
486 (dyld_bfd, bfd_object, gdbarch_bfd_arch_info (target_gdbarch ()));
490 make_cleanup_bfd_unref (sub);
497 do_cleanups (cleanup);
501 /* We find the dynamic linker's base address by examining
502 the current pc (which should point at the entry point for the
503 dynamic linker) and subtracting the offset of the entry point. */
504 load_addr = (regcache_read_pc (get_current_regcache ())
505 - bfd_get_start_address (dyld_bfd));
507 /* Now try to set a breakpoint in the dynamic linker. */
508 info->all_image_addr =
509 lookup_symbol_from_bfd (dyld_bfd, "_dyld_all_image_infos");
511 do_cleanups (cleanup);
513 if (info->all_image_addr == 0)
516 info->all_image_addr += load_addr;
519 /* Extract dyld_all_image_addr reading it from
520 TARGET_OBJECT_DARWIN_DYLD_INFO. */
523 darwin_solib_read_all_image_info_addr (struct darwin_info *info)
527 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
528 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
531 if (TYPE_LENGTH (ptr_type) > sizeof (buf))
534 len = target_read (¤t_target, TARGET_OBJECT_DARWIN_DYLD_INFO, NULL,
535 buf, 0, TYPE_LENGTH (ptr_type));
539 /* The use of BIG endian is intended, as BUF is a raw stream of bytes. This
540 makes the support of remote protocol easier. */
541 info->all_image_addr = extract_unsigned_integer (buf, len, BFD_ENDIAN_BIG);
544 /* Shared library startup support. See documentation in solib-svr4.c. */
547 darwin_solib_create_inferior_hook (int from_tty)
549 struct darwin_info *info = get_darwin_info ();
552 info->all_image_addr = 0;
554 darwin_solib_read_all_image_info_addr (info);
556 if (info->all_image_addr == 0)
557 darwin_solib_get_all_image_info_addr_at_init (info);
559 if (info->all_image_addr == 0)
562 darwin_load_image_infos (info);
564 if (!darwin_dyld_version_ok (info))
566 warning (_("unhandled dyld version (%d)"), info->all_image.version);
570 /* Add the breakpoint which is hit by dyld when the list of solib is
572 create_solib_event_breakpoint (target_gdbarch (), info->all_image.notifier);
574 if (info->all_image.count != 0)
576 /* Possible relocate the main executable (PIE). */
577 load_addr = darwin_read_exec_load_addr_from_dyld (info);
582 Do not break on the notifier if dyld is not initialized (deduced from
583 count == 0). In that case, dyld hasn't relocated itself and the
584 notifier may point to a wrong address. */
586 load_addr = darwin_read_exec_load_addr_at_init (info);
589 if (load_addr != 0 && symfile_objfile != NULL)
593 /* Find the base address of the executable. */
594 vmaddr = bfd_mach_o_get_base_address (exec_bfd);
597 if (vmaddr != load_addr)
598 objfile_rebase (symfile_objfile, load_addr - vmaddr);
603 darwin_clear_solib (void)
605 struct darwin_info *info = get_darwin_info ();
607 info->all_image_addr = 0;
608 info->all_image.version = 0;
612 darwin_free_so (struct so_list *so)
616 /* The section table is built from bfd sections using bfd VMAs.
617 Relocate these VMAs according to solib info. */
620 darwin_relocate_section_addresses (struct so_list *so,
621 struct target_section *sec)
623 sec->addr += so->lm_info->lm_addr;
624 sec->endaddr += so->lm_info->lm_addr;
626 /* Best effort to set addr_high/addr_low. This is used only by
627 'info sharedlibary'. */
628 if (so->addr_high == 0)
630 so->addr_low = sec->addr;
631 so->addr_high = sec->endaddr;
633 if (sec->endaddr > so->addr_high)
634 so->addr_high = sec->endaddr;
635 if (sec->addr < so->addr_low)
636 so->addr_low = sec->addr;
639 static struct block_symbol
640 darwin_lookup_lib_symbol (struct objfile *objfile,
642 const domain_enum domain)
644 return (struct block_symbol) {NULL, NULL};
648 darwin_bfd_open (char *pathname)
650 char *found_pathname;
655 /* Search for shared library file. */
656 found_pathname = solib_find (pathname, &found_file);
657 if (found_pathname == NULL)
658 perror_with_name (pathname);
660 /* Open bfd for shared library. */
661 abfd = solib_bfd_fopen (found_pathname, found_file);
663 res = gdb_bfd_mach_o_fat_extract (abfd, bfd_object,
664 gdbarch_bfd_arch_info (target_gdbarch ()));
667 make_cleanup_bfd_unref (abfd);
668 error (_("`%s': not a shared-library: %s"),
669 bfd_get_filename (abfd), bfd_errmsg (bfd_get_error ()));
672 /* The current filename for fat-binary BFDs is a name generated
673 by BFD, usually a string containing the name of the architecture.
674 Reset its value to the actual filename. */
675 xfree (bfd_get_filename (res));
676 res->filename = xstrdup (pathname);
678 gdb_bfd_unref (abfd);
682 struct target_so_ops darwin_so_ops;
684 /* -Wmissing-prototypes */
685 extern initialize_file_ftype _initialize_darwin_solib;
688 _initialize_darwin_solib (void)
690 solib_darwin_pspace_data
691 = register_program_space_data_with_cleanup (NULL,
692 darwin_pspace_data_cleanup);
694 darwin_so_ops.relocate_section_addresses = darwin_relocate_section_addresses;
695 darwin_so_ops.free_so = darwin_free_so;
696 darwin_so_ops.clear_solib = darwin_clear_solib;
697 darwin_so_ops.solib_create_inferior_hook = darwin_solib_create_inferior_hook;
698 darwin_so_ops.special_symbol_handling = darwin_special_symbol_handling;
699 darwin_so_ops.current_sos = darwin_current_sos;
700 darwin_so_ops.open_symbol_file_object = open_symbol_file_object;
701 darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;
702 darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
703 darwin_so_ops.bfd_open = darwin_bfd_open;