1 /* Handle Darwin shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 2009-2017 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. */
156 struct lm_info_darwin : public lm_info_base
158 /* The target location of lm. */
162 /* Lookup the value for a specific symbol. */
165 lookup_symbol_from_bfd (bfd *abfd, const char *symname)
168 asymbol **symbol_table;
169 unsigned int number_of_symbols;
171 CORE_ADDR symaddr = 0;
173 storage_needed = bfd_get_symtab_upper_bound (abfd);
175 if (storage_needed <= 0)
178 symbol_table = (asymbol **) xmalloc (storage_needed);
179 number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
181 for (i = 0; i < number_of_symbols; i++)
183 asymbol *sym = symbol_table[i];
185 if (strcmp (sym->name, symname) == 0
186 && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
188 /* BFD symbols are section relative. */
189 symaddr = sym->value + sym->section->vma;
193 xfree (symbol_table);
198 /* Return program interpreter string. */
201 find_program_interpreter (void)
205 /* If we have an exec_bfd, get the interpreter from the load commands. */
208 bfd_mach_o_load_command *cmd;
210 if (bfd_mach_o_lookup_command (exec_bfd,
211 BFD_MACH_O_LC_LOAD_DYLINKER, &cmd) == 1)
212 return cmd->command.dylinker.name_str;
215 /* If we didn't find it, read from memory.
220 /* Not used. I don't see how the main symbol file can be found: the
221 interpreter name is needed and it is known from the executable file.
222 Note that darwin-nat.c implements pid_to_exec_file. */
225 open_symbol_file_object (void *from_ttyp)
230 /* Build a list of currently loaded shared objects. See solib-svr4.c. */
232 static struct so_list *
233 darwin_current_sos (void)
235 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
236 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
237 int ptr_len = TYPE_LENGTH (ptr_type);
238 unsigned int image_info_size;
239 struct so_list *head = NULL;
240 struct so_list *tail = NULL;
242 struct darwin_info *info = get_darwin_info ();
244 /* Be sure image infos are loaded. */
245 darwin_load_image_infos (info);
247 if (!darwin_dyld_version_ok (info))
250 image_info_size = ptr_len * 3;
252 /* Read infos for each solib.
253 The first entry was rumored to be the executable itself, but this is not
254 true when a large number of shared libraries are used (table expanded ?).
255 We now check all entries, but discard executable images. */
256 for (i = 0; i < info->all_image.count; i++)
258 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
259 gdb_byte buf[image_info_size];
262 struct mach_o_header_external hdr;
263 unsigned long hdr_val;
266 struct so_list *newobj;
267 struct cleanup *old_chain;
269 /* Read image info from inferior. */
270 if (target_read_memory (iinfo, buf, image_info_size))
273 load_addr = extract_typed_address (buf, ptr_type);
274 path_addr = extract_typed_address (buf + ptr_len, ptr_type);
276 /* Read Mach-O header from memory. */
277 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
279 /* Discard wrong magic numbers. Shouldn't happen. */
280 hdr_val = extract_unsigned_integer
281 (hdr.magic, sizeof (hdr.magic), byte_order);
282 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
284 /* Discard executable. Should happen only once. */
285 hdr_val = extract_unsigned_integer
286 (hdr.filetype, sizeof (hdr.filetype), byte_order);
287 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
290 target_read_string (path_addr, &file_path,
291 SO_NAME_MAX_PATH_SIZE - 1, &errcode);
295 /* Create and fill the new so_list element. */
296 newobj = XCNEW (struct so_list);
297 old_chain = make_cleanup (xfree, newobj);
299 lm_info_darwin *li = XCNEW (lm_info_darwin);
300 newobj->lm_info = li;
302 strncpy (newobj->so_name, file_path, SO_NAME_MAX_PATH_SIZE - 1);
303 newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
304 strcpy (newobj->so_original_name, newobj->so_name);
306 li->lm_addr = load_addr;
314 discard_cleanups (old_chain);
320 /* Check LOAD_ADDR points to a Mach-O executable header. Return LOAD_ADDR
321 in case of success, 0 in case of failure. */
324 darwin_validate_exec_header (CORE_ADDR load_addr)
326 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
327 struct mach_o_header_external hdr;
328 unsigned long hdr_val;
330 /* Read Mach-O header from memory. */
331 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
334 /* Discard wrong magic numbers. Shouldn't happen. */
335 hdr_val = extract_unsigned_integer
336 (hdr.magic, sizeof (hdr.magic), byte_order);
337 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
340 /* Check executable. */
341 hdr_val = extract_unsigned_integer
342 (hdr.filetype, sizeof (hdr.filetype), byte_order);
343 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
349 /* Get the load address of the executable using dyld list of images.
350 We assume that the dyld info are correct (which is wrong if the target
351 is stopped at the first instruction). */
354 darwin_read_exec_load_addr_from_dyld (struct darwin_info *info)
356 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
357 int ptr_len = TYPE_LENGTH (ptr_type);
358 unsigned int image_info_size = ptr_len * 3;
361 /* Read infos for each solib. One of them should be the executable. */
362 for (i = 0; i < info->all_image.count; i++)
364 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
365 gdb_byte buf[image_info_size];
368 /* Read image info from inferior. */
369 if (target_read_memory (iinfo, buf, image_info_size))
372 load_addr = extract_typed_address (buf, ptr_type);
373 if (darwin_validate_exec_header (load_addr) == load_addr)
380 /* Get the load address of the executable when the PC is at the dyld
381 entry point using parameter passed by the kernel (at SP). */
384 darwin_read_exec_load_addr_at_init (struct darwin_info *info)
386 struct gdbarch *gdbarch = target_gdbarch ();
387 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
388 int addr_size = gdbarch_addr_bit (gdbarch) / 8;
389 ULONGEST load_ptr_addr;
394 if (regcache_cooked_read_unsigned (get_current_regcache (),
395 gdbarch_sp_regnum (gdbarch),
396 &load_ptr_addr) != REG_VALID)
399 /* Read value at SP (image load address). */
400 if (target_read_memory (load_ptr_addr, buf, addr_size))
403 load_addr = extract_unsigned_integer (buf, addr_size, byte_order);
405 return darwin_validate_exec_header (load_addr);
408 /* Return 1 if PC lies in the dynamic symbol resolution code of the
412 darwin_in_dynsym_resolve_code (CORE_ADDR pc)
417 /* A wrapper for bfd_mach_o_fat_extract that handles reference
418 counting properly. This will either return NULL, or return a new
419 reference to a BFD. */
421 static gdb_bfd_ref_ptr
422 gdb_bfd_mach_o_fat_extract (bfd *abfd, bfd_format format,
423 const bfd_arch_info_type *arch)
425 bfd *result = bfd_mach_o_fat_extract (abfd, format, arch);
431 gdb_bfd_ref (result);
433 gdb_bfd_mark_parent (result, abfd);
435 return gdb_bfd_ref_ptr (result);
438 /* Extract dyld_all_image_addr when the process was just created, assuming the
439 current PC is at the entry of the dynamic linker. */
442 darwin_solib_get_all_image_info_addr_at_init (struct darwin_info *info)
445 CORE_ADDR load_addr = 0;
447 /* This method doesn't work with an attached process. */
448 if (current_inferior ()->attach_flag)
451 /* Find the program interpreter. */
452 interp_name = find_program_interpreter ();
456 /* Create a bfd for the interpreter. */
457 gdb_bfd_ref_ptr dyld_bfd (gdb_bfd_open (interp_name, gnutarget, -1));
458 if (dyld_bfd != NULL)
461 (gdb_bfd_mach_o_fat_extract (dyld_bfd.get (), bfd_object,
462 gdbarch_bfd_arch_info (target_gdbarch ())));
468 if (dyld_bfd == NULL)
471 /* We find the dynamic linker's base address by examining
472 the current pc (which should point at the entry point for the
473 dynamic linker) and subtracting the offset of the entry point. */
474 load_addr = (regcache_read_pc (get_current_regcache ())
475 - bfd_get_start_address (dyld_bfd.get ()));
477 /* Now try to set a breakpoint in the dynamic linker. */
478 info->all_image_addr =
479 lookup_symbol_from_bfd (dyld_bfd.get (), "_dyld_all_image_infos");
481 if (info->all_image_addr == 0)
484 info->all_image_addr += load_addr;
487 /* Extract dyld_all_image_addr reading it from
488 TARGET_OBJECT_DARWIN_DYLD_INFO. */
491 darwin_solib_read_all_image_info_addr (struct darwin_info *info)
495 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
498 if (TYPE_LENGTH (ptr_type) > sizeof (buf))
501 len = target_read (¤t_target, TARGET_OBJECT_DARWIN_DYLD_INFO, NULL,
502 buf, 0, TYPE_LENGTH (ptr_type));
506 /* The use of BIG endian is intended, as BUF is a raw stream of bytes. This
507 makes the support of remote protocol easier. */
508 info->all_image_addr = extract_unsigned_integer (buf, len, BFD_ENDIAN_BIG);
511 /* Shared library startup support. See documentation in solib-svr4.c. */
514 darwin_solib_create_inferior_hook (int from_tty)
516 struct darwin_info *info = get_darwin_info ();
519 info->all_image_addr = 0;
521 darwin_solib_read_all_image_info_addr (info);
523 if (info->all_image_addr == 0)
524 darwin_solib_get_all_image_info_addr_at_init (info);
526 if (info->all_image_addr == 0)
529 darwin_load_image_infos (info);
531 if (!darwin_dyld_version_ok (info))
533 warning (_("unhandled dyld version (%d)"), info->all_image.version);
537 /* Add the breakpoint which is hit by dyld when the list of solib is
539 create_solib_event_breakpoint (target_gdbarch (), info->all_image.notifier);
541 if (info->all_image.count != 0)
543 /* Possible relocate the main executable (PIE). */
544 load_addr = darwin_read_exec_load_addr_from_dyld (info);
549 Do not break on the notifier if dyld is not initialized (deduced from
550 count == 0). In that case, dyld hasn't relocated itself and the
551 notifier may point to a wrong address. */
553 load_addr = darwin_read_exec_load_addr_at_init (info);
556 if (load_addr != 0 && symfile_objfile != NULL)
560 /* Find the base address of the executable. */
561 vmaddr = bfd_mach_o_get_base_address (exec_bfd);
564 if (vmaddr != load_addr)
565 objfile_rebase (symfile_objfile, load_addr - vmaddr);
570 darwin_clear_solib (void)
572 struct darwin_info *info = get_darwin_info ();
574 info->all_image_addr = 0;
575 info->all_image.version = 0;
579 darwin_free_so (struct so_list *so)
584 /* The section table is built from bfd sections using bfd VMAs.
585 Relocate these VMAs according to solib info. */
588 darwin_relocate_section_addresses (struct so_list *so,
589 struct target_section *sec)
591 lm_info_darwin *li = (lm_info_darwin *) so->lm_info;
593 sec->addr += li->lm_addr;
594 sec->endaddr += li->lm_addr;
596 /* Best effort to set addr_high/addr_low. This is used only by
597 'info sharedlibary'. */
598 if (so->addr_high == 0)
600 so->addr_low = sec->addr;
601 so->addr_high = sec->endaddr;
603 if (sec->endaddr > so->addr_high)
604 so->addr_high = sec->endaddr;
605 if (sec->addr < so->addr_low)
606 so->addr_low = sec->addr;
609 static struct block_symbol
610 darwin_lookup_lib_symbol (struct objfile *objfile,
612 const domain_enum domain)
614 return (struct block_symbol) {NULL, NULL};
617 static gdb_bfd_ref_ptr
618 darwin_bfd_open (char *pathname)
620 char *found_pathname;
623 /* Search for shared library file. */
624 found_pathname = solib_find (pathname, &found_file);
625 if (found_pathname == NULL)
626 perror_with_name (pathname);
628 /* Open bfd for shared library. */
629 gdb_bfd_ref_ptr abfd (solib_bfd_fopen (found_pathname, found_file));
632 (gdb_bfd_mach_o_fat_extract (abfd.get (), bfd_object,
633 gdbarch_bfd_arch_info (target_gdbarch ())));
635 error (_("`%s': not a shared-library: %s"),
636 bfd_get_filename (abfd.get ()), bfd_errmsg (bfd_get_error ()));
638 /* The current filename for fat-binary BFDs is a name generated
639 by BFD, usually a string containing the name of the architecture.
640 Reset its value to the actual filename. */
641 xfree (bfd_get_filename (res.get ()));
642 res->filename = xstrdup (pathname);
647 struct target_so_ops darwin_so_ops;
649 /* -Wmissing-prototypes */
650 extern initialize_file_ftype _initialize_darwin_solib;
653 _initialize_darwin_solib (void)
655 solib_darwin_pspace_data
656 = register_program_space_data_with_cleanup (NULL,
657 darwin_pspace_data_cleanup);
659 darwin_so_ops.relocate_section_addresses = darwin_relocate_section_addresses;
660 darwin_so_ops.free_so = darwin_free_so;
661 darwin_so_ops.clear_solib = darwin_clear_solib;
662 darwin_so_ops.solib_create_inferior_hook = darwin_solib_create_inferior_hook;
663 darwin_so_ops.current_sos = darwin_current_sos;
664 darwin_so_ops.open_symbol_file_object = open_symbol_file_object;
665 darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;
666 darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
667 darwin_so_ops.bfd_open = darwin_bfd_open;