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 = 0;
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 program_space_key<darwin_info> solib_darwin_pspace_data;
85 /* Get the current darwin data. If none is found yet, add it now. This
86 function always returns a valid object. */
88 static struct darwin_info *
89 get_darwin_info (void)
91 struct darwin_info *info;
93 info = solib_darwin_pspace_data.get (current_program_space);
97 return solib_darwin_pspace_data.emplace (current_program_space);
100 /* Return non-zero if the version in dyld_all_image is known. */
103 darwin_dyld_version_ok (const struct darwin_info *info)
105 return info->all_image.version >= DYLD_VERSION_MIN
106 && info->all_image.version <= DYLD_VERSION_MAX;
109 /* Read dyld_all_image from inferior. */
112 darwin_load_image_infos (struct darwin_info *info)
115 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
116 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
119 /* If the structure address is not known, don't continue. */
120 if (info->all_image_addr == 0)
123 /* The structure has 4 fields: version (4 bytes), count (4 bytes),
124 info (pointer) and notifier (pointer). */
125 len = 4 + 4 + 2 * TYPE_LENGTH (ptr_type);
126 gdb_assert (len <= sizeof (buf));
127 memset (&info->all_image, 0, sizeof (info->all_image));
129 /* Read structure raw bytes from target. */
130 if (target_read_memory (info->all_image_addr, buf, len))
133 /* Extract the fields. */
134 info->all_image.version = extract_unsigned_integer (buf, 4, byte_order);
135 if (!darwin_dyld_version_ok (info))
138 info->all_image.count = extract_unsigned_integer (buf + 4, 4, byte_order);
139 info->all_image.info = extract_typed_address (buf + 8, ptr_type);
140 info->all_image.notifier = extract_typed_address
141 (buf + 8 + TYPE_LENGTH (ptr_type), ptr_type);
144 /* Link map info to include in an allocated so_list entry. */
146 struct lm_info_darwin : public lm_info_base
148 /* The target location of lm. */
149 CORE_ADDR lm_addr = 0;
152 /* Lookup the value for a specific symbol. */
155 lookup_symbol_from_bfd (bfd *abfd, const char *symname)
158 asymbol **symbol_table;
159 unsigned int number_of_symbols;
161 CORE_ADDR symaddr = 0;
163 storage_needed = bfd_get_symtab_upper_bound (abfd);
165 if (storage_needed <= 0)
168 symbol_table = (asymbol **) xmalloc (storage_needed);
169 number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table);
171 for (i = 0; i < number_of_symbols; i++)
173 asymbol *sym = symbol_table[i];
175 if (strcmp (sym->name, symname) == 0
176 && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0)
178 /* BFD symbols are section relative. */
179 symaddr = sym->value + sym->section->vma;
183 xfree (symbol_table);
188 /* Return program interpreter string. */
191 find_program_interpreter (void)
195 /* If we have an exec_bfd, get the interpreter from the load commands. */
198 bfd_mach_o_load_command *cmd;
200 if (bfd_mach_o_lookup_command (exec_bfd,
201 BFD_MACH_O_LC_LOAD_DYLINKER, &cmd) == 1)
202 return cmd->command.dylinker.name_str;
205 /* If we didn't find it, read from memory.
210 /* Not used. I don't see how the main symbol file can be found: the
211 interpreter name is needed and it is known from the executable file.
212 Note that darwin-nat.c implements pid_to_exec_file. */
215 open_symbol_file_object (int from_tty)
220 /* Build a list of currently loaded shared objects. See solib-svr4.c. */
222 static struct so_list *
223 darwin_current_sos (void)
225 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
226 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
227 int ptr_len = TYPE_LENGTH (ptr_type);
228 unsigned int image_info_size;
229 struct so_list *head = NULL;
230 struct so_list *tail = NULL;
232 struct darwin_info *info = get_darwin_info ();
234 /* Be sure image infos are loaded. */
235 darwin_load_image_infos (info);
237 if (!darwin_dyld_version_ok (info))
240 image_info_size = ptr_len * 3;
242 /* Read infos for each solib.
243 The first entry was rumored to be the executable itself, but this is not
244 true when a large number of shared libraries are used (table expanded ?).
245 We now check all entries, but discard executable images. */
246 for (i = 0; i < info->all_image.count; i++)
248 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
249 gdb_byte buf[image_info_size];
252 struct mach_o_header_external hdr;
253 unsigned long hdr_val;
254 gdb::unique_xmalloc_ptr<char> file_path;
257 /* Read image info from inferior. */
258 if (target_read_memory (iinfo, buf, image_info_size))
261 load_addr = extract_typed_address (buf, ptr_type);
262 path_addr = extract_typed_address (buf + ptr_len, ptr_type);
264 /* Read Mach-O header from memory. */
265 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
267 /* Discard wrong magic numbers. Shouldn't happen. */
268 hdr_val = extract_unsigned_integer
269 (hdr.magic, sizeof (hdr.magic), byte_order);
270 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
272 /* Discard executable. Should happen only once. */
273 hdr_val = extract_unsigned_integer
274 (hdr.filetype, sizeof (hdr.filetype), byte_order);
275 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
278 target_read_string (path_addr, &file_path,
279 SO_NAME_MAX_PATH_SIZE - 1, &errcode);
283 /* Create and fill the new so_list element. */
284 gdb::unique_xmalloc_ptr<struct so_list> newobj (XCNEW (struct so_list));
286 lm_info_darwin *li = new lm_info_darwin;
287 newobj->lm_info = li;
289 strncpy (newobj->so_name, file_path.get (), SO_NAME_MAX_PATH_SIZE - 1);
290 newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
291 strcpy (newobj->so_original_name, newobj->so_name);
292 li->lm_addr = load_addr;
295 head = newobj.get ();
297 tail->next = newobj.get ();
298 tail = newobj.release ();
304 /* Check LOAD_ADDR points to a Mach-O executable header. Return LOAD_ADDR
305 in case of success, 0 in case of failure. */
308 darwin_validate_exec_header (CORE_ADDR load_addr)
310 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
311 struct mach_o_header_external hdr;
312 unsigned long hdr_val;
314 /* Read Mach-O header from memory. */
315 if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
318 /* Discard wrong magic numbers. Shouldn't happen. */
319 hdr_val = extract_unsigned_integer
320 (hdr.magic, sizeof (hdr.magic), byte_order);
321 if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64)
324 /* Check executable. */
325 hdr_val = extract_unsigned_integer
326 (hdr.filetype, sizeof (hdr.filetype), byte_order);
327 if (hdr_val == BFD_MACH_O_MH_EXECUTE)
333 /* Get the load address of the executable using dyld list of images.
334 We assume that the dyld info are correct (which is wrong if the target
335 is stopped at the first instruction). */
338 darwin_read_exec_load_addr_from_dyld (struct darwin_info *info)
340 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
341 int ptr_len = TYPE_LENGTH (ptr_type);
342 unsigned int image_info_size = ptr_len * 3;
345 /* Read infos for each solib. One of them should be the executable. */
346 for (i = 0; i < info->all_image.count; i++)
348 CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
349 gdb_byte buf[image_info_size];
352 /* Read image info from inferior. */
353 if (target_read_memory (iinfo, buf, image_info_size))
356 load_addr = extract_typed_address (buf, ptr_type);
357 if (darwin_validate_exec_header (load_addr) == load_addr)
364 /* Get the load address of the executable when the PC is at the dyld
365 entry point using parameter passed by the kernel (at SP). */
368 darwin_read_exec_load_addr_at_init (struct darwin_info *info)
370 struct gdbarch *gdbarch = target_gdbarch ();
371 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
372 int addr_size = gdbarch_addr_bit (gdbarch) / 8;
373 ULONGEST load_ptr_addr;
378 if (regcache_cooked_read_unsigned (get_current_regcache (),
379 gdbarch_sp_regnum (gdbarch),
380 &load_ptr_addr) != REG_VALID)
383 /* Read value at SP (image load address). */
384 if (target_read_memory (load_ptr_addr, buf, addr_size))
387 load_addr = extract_unsigned_integer (buf, addr_size, byte_order);
389 return darwin_validate_exec_header (load_addr);
392 /* Return 1 if PC lies in the dynamic symbol resolution code of the
396 darwin_in_dynsym_resolve_code (CORE_ADDR pc)
401 /* A wrapper for bfd_mach_o_fat_extract that handles reference
402 counting properly. This will either return NULL, or return a new
403 reference to a BFD. */
405 static gdb_bfd_ref_ptr
406 gdb_bfd_mach_o_fat_extract (bfd *abfd, bfd_format format,
407 const bfd_arch_info_type *arch)
409 bfd *result = bfd_mach_o_fat_extract (abfd, format, arch);
415 gdb_bfd_ref (result);
417 gdb_bfd_mark_parent (result, abfd);
419 return gdb_bfd_ref_ptr (result);
422 /* Return the BFD for the program interpreter. */
424 static gdb_bfd_ref_ptr
425 darwin_get_dyld_bfd ()
429 /* This method doesn't work with an attached process. */
430 if (current_inferior ()->attach_flag)
433 /* Find the program interpreter. */
434 interp_name = find_program_interpreter ();
438 /* Create a bfd for the interpreter. */
439 gdb_bfd_ref_ptr dyld_bfd (gdb_bfd_open (interp_name, gnutarget, -1));
440 if (dyld_bfd != NULL)
443 (gdb_bfd_mach_o_fat_extract (dyld_bfd.get (), bfd_object,
444 gdbarch_bfd_arch_info (target_gdbarch ())));
450 /* Extract dyld_all_image_addr when the process was just created, assuming the
451 current PC is at the entry of the dynamic linker. */
454 darwin_solib_get_all_image_info_addr_at_init (struct darwin_info *info)
456 CORE_ADDR load_addr = 0;
457 gdb_bfd_ref_ptr dyld_bfd = darwin_get_dyld_bfd ();
459 if (dyld_bfd == NULL)
462 /* We find the dynamic linker's base address by examining
463 the current pc (which should point at the entry point for the
464 dynamic linker) and subtracting the offset of the entry point. */
465 load_addr = (regcache_read_pc (get_current_regcache ())
466 - bfd_get_start_address (dyld_bfd.get ()));
468 /* Now try to set a breakpoint in the dynamic linker. */
469 info->all_image_addr =
470 lookup_symbol_from_bfd (dyld_bfd.get (), "_dyld_all_image_infos");
472 if (info->all_image_addr == 0)
475 info->all_image_addr += load_addr;
478 /* Extract dyld_all_image_addr reading it from
479 TARGET_OBJECT_DARWIN_DYLD_INFO. */
482 darwin_solib_read_all_image_info_addr (struct darwin_info *info)
486 struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
489 if (TYPE_LENGTH (ptr_type) > sizeof (buf))
492 len = target_read (current_top_target (), TARGET_OBJECT_DARWIN_DYLD_INFO,
493 NULL, buf, 0, TYPE_LENGTH (ptr_type));
497 /* The use of BIG endian is intended, as BUF is a raw stream of bytes. This
498 makes the support of remote protocol easier. */
499 info->all_image_addr = extract_unsigned_integer (buf, len, BFD_ENDIAN_BIG);
502 /* Shared library startup support. See documentation in solib-svr4.c. */
505 darwin_solib_create_inferior_hook (int from_tty)
507 struct darwin_info *info = get_darwin_info ();
510 info->all_image_addr = 0;
512 darwin_solib_read_all_image_info_addr (info);
514 if (info->all_image_addr == 0)
515 darwin_solib_get_all_image_info_addr_at_init (info);
517 if (info->all_image_addr == 0)
520 darwin_load_image_infos (info);
522 if (!darwin_dyld_version_ok (info))
524 warning (_("unhandled dyld version (%d)"), info->all_image.version);
528 if (info->all_image.count != 0)
530 /* Possible relocate the main executable (PIE). */
531 load_addr = darwin_read_exec_load_addr_from_dyld (info);
536 Do not break on the notifier if dyld is not initialized (deduced from
537 count == 0). In that case, dyld hasn't relocated itself and the
538 notifier may point to a wrong address. */
540 load_addr = darwin_read_exec_load_addr_at_init (info);
543 if (load_addr != 0 && symfile_objfile != NULL)
547 /* Find the base address of the executable. */
548 vmaddr = bfd_mach_o_get_base_address (exec_bfd);
551 if (vmaddr != load_addr)
552 objfile_rebase (symfile_objfile, load_addr - vmaddr);
555 /* Set solib notifier (to reload list of shared libraries). */
556 CORE_ADDR notifier = info->all_image.notifier;
558 if (info->all_image.count == 0)
560 /* Dyld hasn't yet relocated itself, so the notifier address may
561 be incorrect (as it has to be relocated). */
562 CORE_ADDR start = bfd_get_start_address (exec_bfd);
567 gdb_bfd_ref_ptr dyld_bfd = darwin_get_dyld_bfd ();
568 if (dyld_bfd != NULL)
570 CORE_ADDR dyld_bfd_start_address;
571 CORE_ADDR dyld_relocated_base_address;
574 dyld_bfd_start_address = bfd_get_start_address (dyld_bfd.get());
576 /* We find the dynamic linker's base address by examining
577 the current pc (which should point at the entry point
578 for the dynamic linker) and subtracting the offset of
581 pc = regcache_read_pc (get_current_regcache ());
582 dyld_relocated_base_address = pc - dyld_bfd_start_address;
584 /* We get the proper notifier relocated address by
585 adding the dyld relocated base address to the current
586 notifier offset value. */
588 notifier += dyld_relocated_base_address;
593 /* Add the breakpoint which is hit by dyld when the list of solib is
596 create_solib_event_breakpoint (target_gdbarch (), notifier);
600 darwin_clear_solib (void)
602 struct darwin_info *info = get_darwin_info ();
604 info->all_image_addr = 0;
605 info->all_image.version = 0;
609 darwin_free_so (struct so_list *so)
611 lm_info_darwin *li = (lm_info_darwin *) so->lm_info;
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 lm_info_darwin *li = (lm_info_darwin *) so->lm_info;
625 sec->addr += li->lm_addr;
626 sec->endaddr += li->lm_addr;
628 /* Best effort to set addr_high/addr_low. This is used only by
629 'info sharedlibary'. */
630 if (so->addr_high == 0)
632 so->addr_low = sec->addr;
633 so->addr_high = sec->endaddr;
635 if (sec->endaddr > so->addr_high)
636 so->addr_high = sec->endaddr;
637 if (sec->addr < so->addr_low)
638 so->addr_low = sec->addr;
641 static struct block_symbol
642 darwin_lookup_lib_symbol (struct objfile *objfile,
644 const domain_enum domain)
649 static gdb_bfd_ref_ptr
650 darwin_bfd_open (const char *pathname)
654 /* Search for shared library file. */
655 gdb::unique_xmalloc_ptr<char> found_pathname
656 = solib_find (pathname, &found_file);
657 if (found_pathname == NULL)
658 perror_with_name (pathname);
660 /* Open bfd for shared library. */
661 gdb_bfd_ref_ptr abfd (solib_bfd_fopen (found_pathname.get (), found_file));
664 (gdb_bfd_mach_o_fat_extract (abfd.get (), bfd_object,
665 gdbarch_bfd_arch_info (target_gdbarch ())));
667 error (_("`%s': not a shared-library: %s"),
668 bfd_get_filename (abfd.get ()), bfd_errmsg (bfd_get_error ()));
670 /* The current filename for fat-binary BFDs is a name generated
671 by BFD, usually a string containing the name of the architecture.
672 Reset its value to the actual filename. */
673 xfree (bfd_get_filename (res.get ()));
674 res->filename = xstrdup (pathname);
679 struct target_so_ops darwin_so_ops;
682 _initialize_darwin_solib (void)
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;