1 /* Handle Darwin shared libraries for GDB, the GNU Debugger.
3 Copyright (C) 2009-2019 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 15
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. */
159 CORE_ADDR lm_addr = 0;
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 (int from_tty)
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;
264 gdb::unique_xmalloc_ptr<char> file_path;
267 /* Read image info from inferior. */
268 if (target_read_memory (iinfo, buf, image_info_size))
271 load_addr = extract_typed_address (buf, ptr_type);
272 path_addr = extract_typed_address (buf + ptr_len, ptr_type);
274 /* Read Mach-O header from memory. */
275 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
277 /* Discard wrong magic numbers. Shouldn't happen. */
278 hdr_val = extract_unsigned_integer
279 (hdr.magic, sizeof (hdr.magic), byte_order);
280 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
282 /* Discard executable. Should happen only once. */
283 hdr_val = extract_unsigned_integer
284 (hdr.filetype, sizeof (hdr.filetype), byte_order);
285 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
288 target_read_string (path_addr, &file_path,
289 SO_NAME_MAX_PATH_SIZE - 1, &errcode);
293 /* Create and fill the new so_list element. */
294 gdb::unique_xmalloc_ptr<struct so_list> newobj (XCNEW (struct so_list));
296 lm_info_darwin *li = new lm_info_darwin;
297 newobj->lm_info = li;
299 strncpy (newobj->so_name, file_path.get (), SO_NAME_MAX_PATH_SIZE - 1);
300 newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
301 strcpy (newobj->so_original_name, newobj->so_name);
302 li->lm_addr = load_addr;
305 head = newobj.get ();
307 tail->next = newobj.get ();
308 tail = newobj.release ();
314 /* Check LOAD_ADDR points to a Mach-O executable header. Return LOAD_ADDR
315 in case of success, 0 in case of failure. */
318 darwin_validate_exec_header (CORE_ADDR load_addr)
320 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
321 struct mach_o_header_external hdr;
322 unsigned long hdr_val;
324 /* Read Mach-O header from memory. */
325 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
328 /* Discard wrong magic numbers. Shouldn't happen. */
329 hdr_val = extract_unsigned_integer
330 (hdr.magic, sizeof (hdr.magic), byte_order);
331 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
334 /* Check executable. */
335 hdr_val = extract_unsigned_integer
336 (hdr.filetype, sizeof (hdr.filetype), byte_order);
337 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
343 /* Get the load address of the executable using dyld list of images.
344 We assume that the dyld info are correct (which is wrong if the target
345 is stopped at the first instruction). */
348 darwin_read_exec_load_addr_from_dyld (struct darwin_info *info)
350 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
351 int ptr_len = TYPE_LENGTH (ptr_type);
352 unsigned int image_info_size = ptr_len * 3;
355 /* Read infos for each solib. One of them should be the executable. */
356 for (i = 0; i < info->all_image.count; i++)
358 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
359 gdb_byte buf[image_info_size];
362 /* Read image info from inferior. */
363 if (target_read_memory (iinfo, buf, image_info_size))
366 load_addr = extract_typed_address (buf, ptr_type);
367 if (darwin_validate_exec_header (load_addr) == load_addr)
374 /* Get the load address of the executable when the PC is at the dyld
375 entry point using parameter passed by the kernel (at SP). */
378 darwin_read_exec_load_addr_at_init (struct darwin_info *info)
380 struct gdbarch *gdbarch = target_gdbarch ();
381 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
382 int addr_size = gdbarch_addr_bit (gdbarch) / 8;
383 ULONGEST load_ptr_addr;
388 if (regcache_cooked_read_unsigned (get_current_regcache (),
389 gdbarch_sp_regnum (gdbarch),
390 &load_ptr_addr) != REG_VALID)
393 /* Read value at SP (image load address). */
394 if (target_read_memory (load_ptr_addr, buf, addr_size))
397 load_addr = extract_unsigned_integer (buf, addr_size, byte_order);
399 return darwin_validate_exec_header (load_addr);
402 /* Return 1 if PC lies in the dynamic symbol resolution code of the
406 darwin_in_dynsym_resolve_code (CORE_ADDR pc)
411 /* A wrapper for bfd_mach_o_fat_extract that handles reference
412 counting properly. This will either return NULL, or return a new
413 reference to a BFD. */
415 static gdb_bfd_ref_ptr
416 gdb_bfd_mach_o_fat_extract (bfd *abfd, bfd_format format,
417 const bfd_arch_info_type *arch)
419 bfd *result = bfd_mach_o_fat_extract (abfd, format, arch);
425 gdb_bfd_ref (result);
427 gdb_bfd_mark_parent (result, abfd);
429 return gdb_bfd_ref_ptr (result);
432 /* Return the BFD for the program interpreter. */
434 static gdb_bfd_ref_ptr
435 darwin_get_dyld_bfd ()
439 /* This method doesn't work with an attached process. */
440 if (current_inferior ()->attach_flag)
443 /* Find the program interpreter. */
444 interp_name = find_program_interpreter ();
448 /* Create a bfd for the interpreter. */
449 gdb_bfd_ref_ptr dyld_bfd (gdb_bfd_open (interp_name, gnutarget, -1));
450 if (dyld_bfd != NULL)
453 (gdb_bfd_mach_o_fat_extract (dyld_bfd.get (), bfd_object,
454 gdbarch_bfd_arch_info (target_gdbarch ())));
460 /* Extract dyld_all_image_addr when the process was just created, assuming the
461 current PC is at the entry of the dynamic linker. */
464 darwin_solib_get_all_image_info_addr_at_init (struct darwin_info *info)
466 CORE_ADDR load_addr = 0;
467 gdb_bfd_ref_ptr dyld_bfd = darwin_get_dyld_bfd ();
469 if (dyld_bfd == NULL)
472 /* We find the dynamic linker's base address by examining
473 the current pc (which should point at the entry point for the
474 dynamic linker) and subtracting the offset of the entry point. */
475 load_addr = (regcache_read_pc (get_current_regcache ())
476 - bfd_get_start_address (dyld_bfd.get ()));
478 /* Now try to set a breakpoint in the dynamic linker. */
479 info->all_image_addr =
480 lookup_symbol_from_bfd (dyld_bfd.get (), "_dyld_all_image_infos");
482 if (info->all_image_addr == 0)
485 info->all_image_addr += load_addr;
488 /* Extract dyld_all_image_addr reading it from
489 TARGET_OBJECT_DARWIN_DYLD_INFO. */
492 darwin_solib_read_all_image_info_addr (struct darwin_info *info)
496 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
499 if (TYPE_LENGTH (ptr_type) > sizeof (buf))
502 len = target_read (current_top_target (), TARGET_OBJECT_DARWIN_DYLD_INFO,
503 NULL, buf, 0, TYPE_LENGTH (ptr_type));
507 /* The use of BIG endian is intended, as BUF is a raw stream of bytes. This
508 makes the support of remote protocol easier. */
509 info->all_image_addr = extract_unsigned_integer (buf, len, BFD_ENDIAN_BIG);
512 /* Shared library startup support. See documentation in solib-svr4.c. */
515 darwin_solib_create_inferior_hook (int from_tty)
517 struct darwin_info *info = get_darwin_info ();
520 info->all_image_addr = 0;
522 darwin_solib_read_all_image_info_addr (info);
524 if (info->all_image_addr == 0)
525 darwin_solib_get_all_image_info_addr_at_init (info);
527 if (info->all_image_addr == 0)
530 darwin_load_image_infos (info);
532 if (!darwin_dyld_version_ok (info))
534 warning (_("unhandled dyld version (%d)"), info->all_image.version);
538 if (info->all_image.count != 0)
540 /* Possible relocate the main executable (PIE). */
541 load_addr = darwin_read_exec_load_addr_from_dyld (info);
546 Do not break on the notifier if dyld is not initialized (deduced from
547 count == 0). In that case, dyld hasn't relocated itself and the
548 notifier may point to a wrong address. */
550 load_addr = darwin_read_exec_load_addr_at_init (info);
553 if (load_addr != 0 && symfile_objfile != NULL)
557 /* Find the base address of the executable. */
558 vmaddr = bfd_mach_o_get_base_address (exec_bfd);
561 if (vmaddr != load_addr)
562 objfile_rebase (symfile_objfile, load_addr - vmaddr);
565 /* Set solib notifier (to reload list of shared libraries). */
566 CORE_ADDR notifier = info->all_image.notifier;
568 if (info->all_image.count == 0)
570 /* Dyld hasn't yet relocated itself, so the notifier address may
571 be incorrect (as it has to be relocated). */
572 CORE_ADDR start = bfd_get_start_address (exec_bfd);
577 gdb_bfd_ref_ptr dyld_bfd = darwin_get_dyld_bfd ();
578 if (dyld_bfd != NULL)
580 CORE_ADDR dyld_bfd_start_address;
581 CORE_ADDR dyld_relocated_base_address;
584 dyld_bfd_start_address = bfd_get_start_address (dyld_bfd.get());
586 /* We find the dynamic linker's base address by examining
587 the current pc (which should point at the entry point
588 for the dynamic linker) and subtracting the offset of
591 pc = regcache_read_pc (get_current_regcache ());
592 dyld_relocated_base_address = pc - dyld_bfd_start_address;
594 /* We get the proper notifier relocated address by
595 adding the dyld relocated base address to the current
596 notifier offset value. */
598 notifier += dyld_relocated_base_address;
603 /* Add the breakpoint which is hit by dyld when the list of solib is
606 create_solib_event_breakpoint (target_gdbarch (), notifier);
610 darwin_clear_solib (void)
612 struct darwin_info *info = get_darwin_info ();
614 info->all_image_addr = 0;
615 info->all_image.version = 0;
619 darwin_free_so (struct so_list *so)
621 lm_info_darwin *li = (lm_info_darwin *) so->lm_info;
626 /* The section table is built from bfd sections using bfd VMAs.
627 Relocate these VMAs according to solib info. */
630 darwin_relocate_section_addresses (struct so_list *so,
631 struct target_section *sec)
633 lm_info_darwin *li = (lm_info_darwin *) so->lm_info;
635 sec->addr += li->lm_addr;
636 sec->endaddr += li->lm_addr;
638 /* Best effort to set addr_high/addr_low. This is used only by
639 'info sharedlibary'. */
640 if (so->addr_high == 0)
642 so->addr_low = sec->addr;
643 so->addr_high = sec->endaddr;
645 if (sec->endaddr > so->addr_high)
646 so->addr_high = sec->endaddr;
647 if (sec->addr < so->addr_low)
648 so->addr_low = sec->addr;
651 static struct block_symbol
652 darwin_lookup_lib_symbol (struct objfile *objfile,
654 const domain_enum domain)
656 return (struct block_symbol) {NULL, NULL};
659 static gdb_bfd_ref_ptr
660 darwin_bfd_open (const char *pathname)
664 /* Search for shared library file. */
665 gdb::unique_xmalloc_ptr<char> found_pathname
666 = solib_find (pathname, &found_file);
667 if (found_pathname == NULL)
668 perror_with_name (pathname);
670 /* Open bfd for shared library. */
671 gdb_bfd_ref_ptr abfd (solib_bfd_fopen (found_pathname.get (), found_file));
674 (gdb_bfd_mach_o_fat_extract (abfd.get (), bfd_object,
675 gdbarch_bfd_arch_info (target_gdbarch ())));
677 error (_("`%s': not a shared-library: %s"),
678 bfd_get_filename (abfd.get ()), bfd_errmsg (bfd_get_error ()));
680 /* The current filename for fat-binary BFDs is a name generated
681 by BFD, usually a string containing the name of the architecture.
682 Reset its value to the actual filename. */
683 xfree (bfd_get_filename (res.get ()));
684 res->filename = xstrdup (pathname);
689 struct target_so_ops darwin_so_ops;
692 _initialize_darwin_solib (void)
694 solib_darwin_pspace_data
695 = register_program_space_data_with_cleanup (NULL,
696 darwin_pspace_data_cleanup);
698 darwin_so_ops.relocate_section_addresses = darwin_relocate_section_addresses;
699 darwin_so_ops.free_so = darwin_free_so;
700 darwin_so_ops.clear_solib = darwin_clear_solib;
701 darwin_so_ops.solib_create_inferior_hook = darwin_solib_create_inferior_hook;
702 darwin_so_ops.current_sos = darwin_current_sos;
703 darwin_so_ops.open_symbol_file_object = open_symbol_file_object;
704 darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;
705 darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
706 darwin_so_ops.bfd_open = darwin_bfd_open;