| /* Handle Darwin shared libraries for GDB, the GNU Debugger. |
| |
| Copyright (C) 2009-2021 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| |
| #include "symtab.h" |
| #include "bfd.h" |
| #include "symfile.h" |
| #include "objfiles.h" |
| #include "gdbcore.h" |
| #include "target.h" |
| #include "inferior.h" |
| #include "regcache.h" |
| #include "gdbthread.h" |
| #include "gdb_bfd.h" |
| |
| #include "solist.h" |
| #include "solib.h" |
| #include "solib-svr4.h" |
| |
| #include "bfd-target.h" |
| #include "elf-bfd.h" |
| #include "exec.h" |
| #include "auxv.h" |
| #include "mach-o.h" |
| #include "mach-o/external.h" |
| |
| struct gdb_dyld_image_info |
| { |
| /* Base address (which corresponds to the Mach-O header). */ |
| CORE_ADDR mach_header; |
| /* Image file path. */ |
| CORE_ADDR file_path; |
| /* st.m_time of image file. */ |
| unsigned long mtime; |
| }; |
| |
| /* Content of inferior dyld_all_image_infos structure. |
| See /usr/include/mach-o/dyld_images.h for the documentation. */ |
| struct gdb_dyld_all_image_infos |
| { |
| /* Version (1). */ |
| unsigned int version; |
| /* Number of images. */ |
| unsigned int count; |
| /* Image description. */ |
| CORE_ADDR info; |
| /* Notifier (function called when a library is added or removed). */ |
| CORE_ADDR notifier; |
| }; |
| |
| /* Current all_image_infos version. */ |
| #define DYLD_VERSION_MIN 1 |
| #define DYLD_VERSION_MAX 15 |
| |
| /* Per PSPACE specific data. */ |
| struct darwin_info |
| { |
| /* Address of structure dyld_all_image_infos in inferior. */ |
| CORE_ADDR all_image_addr = 0; |
| |
| /* Gdb copy of dyld_all_info_infos. */ |
| struct gdb_dyld_all_image_infos all_image {}; |
| }; |
| |
| /* Per-program-space data key. */ |
| static program_space_key<darwin_info> solib_darwin_pspace_data; |
| |
| /* Get the current darwin data. If none is found yet, add it now. This |
| function always returns a valid object. */ |
| |
| static struct darwin_info * |
| get_darwin_info (void) |
| { |
| struct darwin_info *info; |
| |
| info = solib_darwin_pspace_data.get (current_program_space); |
| if (info != NULL) |
| return info; |
| |
| return solib_darwin_pspace_data.emplace (current_program_space); |
| } |
| |
| /* Return non-zero if the version in dyld_all_image is known. */ |
| |
| static int |
| darwin_dyld_version_ok (const struct darwin_info *info) |
| { |
| return info->all_image.version >= DYLD_VERSION_MIN |
| && info->all_image.version <= DYLD_VERSION_MAX; |
| } |
| |
| /* Read dyld_all_image from inferior. */ |
| |
| static void |
| darwin_load_image_infos (struct darwin_info *info) |
| { |
| gdb_byte buf[24]; |
| enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| int len; |
| |
| /* If the structure address is not known, don't continue. */ |
| if (info->all_image_addr == 0) |
| return; |
| |
| /* The structure has 4 fields: version (4 bytes), count (4 bytes), |
| info (pointer) and notifier (pointer). */ |
| len = 4 + 4 + 2 * TYPE_LENGTH (ptr_type); |
| gdb_assert (len <= sizeof (buf)); |
| memset (&info->all_image, 0, sizeof (info->all_image)); |
| |
| /* Read structure raw bytes from target. */ |
| if (target_read_memory (info->all_image_addr, buf, len)) |
| return; |
| |
| /* Extract the fields. */ |
| info->all_image.version = extract_unsigned_integer (buf, 4, byte_order); |
| if (!darwin_dyld_version_ok (info)) |
| return; |
| |
| info->all_image.count = extract_unsigned_integer (buf + 4, 4, byte_order); |
| info->all_image.info = extract_typed_address (buf + 8, ptr_type); |
| info->all_image.notifier = extract_typed_address |
| (buf + 8 + TYPE_LENGTH (ptr_type), ptr_type); |
| } |
| |
| /* Link map info to include in an allocated so_list entry. */ |
| |
| struct lm_info_darwin : public lm_info_base |
| { |
| /* The target location of lm. */ |
| CORE_ADDR lm_addr = 0; |
| }; |
| |
| /* Lookup the value for a specific symbol. */ |
| |
| static CORE_ADDR |
| lookup_symbol_from_bfd (bfd *abfd, const char *symname) |
| { |
| long storage_needed; |
| asymbol **symbol_table; |
| unsigned int number_of_symbols; |
| unsigned int i; |
| CORE_ADDR symaddr = 0; |
| |
| storage_needed = bfd_get_symtab_upper_bound (abfd); |
| |
| if (storage_needed <= 0) |
| return 0; |
| |
| symbol_table = (asymbol **) xmalloc (storage_needed); |
| number_of_symbols = bfd_canonicalize_symtab (abfd, symbol_table); |
| |
| for (i = 0; i < number_of_symbols; i++) |
| { |
| asymbol *sym = symbol_table[i]; |
| |
| if (strcmp (sym->name, symname) == 0 |
| && (sym->section->flags & (SEC_CODE | SEC_DATA)) != 0) |
| { |
| /* BFD symbols are section relative. */ |
| symaddr = sym->value + sym->section->vma; |
| break; |
| } |
| } |
| xfree (symbol_table); |
| |
| return symaddr; |
| } |
| |
| /* Return program interpreter string. */ |
| |
| static char * |
| find_program_interpreter (void) |
| { |
| char *buf = NULL; |
| |
| /* If we have an current exec_bfd, get the interpreter from the load |
| commands. */ |
| if (current_program_space->exec_bfd ()) |
| { |
| bfd_mach_o_load_command *cmd; |
| |
| if (bfd_mach_o_lookup_command (current_program_space->exec_bfd (), |
| BFD_MACH_O_LC_LOAD_DYLINKER, &cmd) == 1) |
| return cmd->command.dylinker.name_str; |
| } |
| |
| /* If we didn't find it, read from memory. |
| FIXME: todo. */ |
| return buf; |
| } |
| |
| /* Not used. I don't see how the main symbol file can be found: the |
| interpreter name is needed and it is known from the executable file. |
| Note that darwin-nat.c implements pid_to_exec_file. */ |
| |
| static int |
| open_symbol_file_object (int from_tty) |
| { |
| return 0; |
| } |
| |
| /* Build a list of currently loaded shared objects. See solib-svr4.c. */ |
| |
| static struct so_list * |
| darwin_current_sos (void) |
| { |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| enum bfd_endian byte_order = type_byte_order (ptr_type); |
| int ptr_len = TYPE_LENGTH (ptr_type); |
| unsigned int image_info_size; |
| struct so_list *head = NULL; |
| struct so_list *tail = NULL; |
| int i; |
| struct darwin_info *info = get_darwin_info (); |
| |
| /* Be sure image infos are loaded. */ |
| darwin_load_image_infos (info); |
| |
| if (!darwin_dyld_version_ok (info)) |
| return NULL; |
| |
| image_info_size = ptr_len * 3; |
| |
| /* Read infos for each solib. |
| The first entry was rumored to be the executable itself, but this is not |
| true when a large number of shared libraries are used (table expanded ?). |
| We now check all entries, but discard executable images. */ |
| for (i = 0; i < info->all_image.count; i++) |
| { |
| CORE_ADDR iinfo = info->all_image.info + i * image_info_size; |
| gdb_byte buf[image_info_size]; |
| CORE_ADDR load_addr; |
| CORE_ADDR path_addr; |
| struct mach_o_header_external hdr; |
| unsigned long hdr_val; |
| |
| /* Read image info from inferior. */ |
| if (target_read_memory (iinfo, buf, image_info_size)) |
| break; |
| |
| load_addr = extract_typed_address (buf, ptr_type); |
| path_addr = extract_typed_address (buf + ptr_len, ptr_type); |
| |
| /* Read Mach-O header from memory. */ |
| if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4)) |
| break; |
| /* Discard wrong magic numbers. Shouldn't happen. */ |
| hdr_val = extract_unsigned_integer |
| (hdr.magic, sizeof (hdr.magic), byte_order); |
| if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64) |
| continue; |
| /* Discard executable. Should happen only once. */ |
| hdr_val = extract_unsigned_integer |
| (hdr.filetype, sizeof (hdr.filetype), byte_order); |
| if (hdr_val == BFD_MACH_O_MH_EXECUTE) |
| continue; |
| |
| gdb::unique_xmalloc_ptr<char> file_path |
| = target_read_string (path_addr, SO_NAME_MAX_PATH_SIZE - 1); |
| if (file_path == nullptr) |
| break; |
| |
| /* Create and fill the new so_list element. */ |
| gdb::unique_xmalloc_ptr<struct so_list> newobj (XCNEW (struct so_list)); |
| |
| lm_info_darwin *li = new lm_info_darwin; |
| newobj->lm_info = li; |
| |
| strncpy (newobj->so_name, file_path.get (), SO_NAME_MAX_PATH_SIZE - 1); |
| newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; |
| strcpy (newobj->so_original_name, newobj->so_name); |
| li->lm_addr = load_addr; |
| |
| if (head == NULL) |
| head = newobj.get (); |
| else |
| tail->next = newobj.get (); |
| tail = newobj.release (); |
| } |
| |
| return head; |
| } |
| |
| /* Check LOAD_ADDR points to a Mach-O executable header. Return LOAD_ADDR |
| in case of success, 0 in case of failure. */ |
| |
| static CORE_ADDR |
| darwin_validate_exec_header (CORE_ADDR load_addr) |
| { |
| enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| struct mach_o_header_external hdr; |
| unsigned long hdr_val; |
| |
| /* Read Mach-O header from memory. */ |
| if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4)) |
| return 0; |
| |
| /* Discard wrong magic numbers. Shouldn't happen. */ |
| hdr_val = extract_unsigned_integer |
| (hdr.magic, sizeof (hdr.magic), byte_order); |
| if (hdr_val != BFD_MACH_O_MH_MAGIC && hdr_val != BFD_MACH_O_MH_MAGIC_64) |
| return 0; |
| |
| /* Check executable. */ |
| hdr_val = extract_unsigned_integer |
| (hdr.filetype, sizeof (hdr.filetype), byte_order); |
| if (hdr_val == BFD_MACH_O_MH_EXECUTE) |
| return load_addr; |
| |
| return 0; |
| } |
| |
| /* Get the load address of the executable using dyld list of images. |
| We assume that the dyld info are correct (which is wrong if the target |
| is stopped at the first instruction). */ |
| |
| static CORE_ADDR |
| darwin_read_exec_load_addr_from_dyld (struct darwin_info *info) |
| { |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| int ptr_len = TYPE_LENGTH (ptr_type); |
| unsigned int image_info_size = ptr_len * 3; |
| int i; |
| |
| /* Read infos for each solib. One of them should be the executable. */ |
| for (i = 0; i < info->all_image.count; i++) |
| { |
| CORE_ADDR iinfo = info->all_image.info + i * image_info_size; |
| gdb_byte buf[image_info_size]; |
| CORE_ADDR load_addr; |
| |
| /* Read image info from inferior. */ |
| if (target_read_memory (iinfo, buf, image_info_size)) |
| break; |
| |
| load_addr = extract_typed_address (buf, ptr_type); |
| if (darwin_validate_exec_header (load_addr) == load_addr) |
| return load_addr; |
| } |
| |
| return 0; |
| } |
| |
| /* Get the load address of the executable when the PC is at the dyld |
| entry point using parameter passed by the kernel (at SP). */ |
| |
| static CORE_ADDR |
| darwin_read_exec_load_addr_at_init (struct darwin_info *info) |
| { |
| struct gdbarch *gdbarch = target_gdbarch (); |
| enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| int addr_size = gdbarch_addr_bit (gdbarch) / 8; |
| ULONGEST load_ptr_addr; |
| ULONGEST load_addr; |
| gdb_byte buf[8]; |
| |
| /* Get SP. */ |
| if (regcache_cooked_read_unsigned (get_current_regcache (), |
| gdbarch_sp_regnum (gdbarch), |
| &load_ptr_addr) != REG_VALID) |
| return 0; |
| |
| /* Read value at SP (image load address). */ |
| if (target_read_memory (load_ptr_addr, buf, addr_size)) |
| return 0; |
| |
| load_addr = extract_unsigned_integer (buf, addr_size, byte_order); |
| |
| return darwin_validate_exec_header (load_addr); |
| } |
| |
| /* Return 1 if PC lies in the dynamic symbol resolution code of the |
| run time loader. */ |
| |
| static int |
| darwin_in_dynsym_resolve_code (CORE_ADDR pc) |
| { |
| return 0; |
| } |
| |
| /* A wrapper for bfd_mach_o_fat_extract that handles reference |
| counting properly. This will either return NULL, or return a new |
| reference to a BFD. */ |
| |
| static gdb_bfd_ref_ptr |
| gdb_bfd_mach_o_fat_extract (bfd *abfd, bfd_format format, |
| const bfd_arch_info_type *arch) |
| { |
| bfd *result = bfd_mach_o_fat_extract (abfd, format, arch); |
| |
| if (result == NULL) |
| return NULL; |
| |
| if (result == abfd) |
| gdb_bfd_ref (result); |
| else |
| gdb_bfd_mark_parent (result, abfd); |
| |
| return gdb_bfd_ref_ptr (result); |
| } |
| |
| /* Return the BFD for the program interpreter. */ |
| |
| static gdb_bfd_ref_ptr |
| darwin_get_dyld_bfd () |
| { |
| char *interp_name; |
| |
| /* This method doesn't work with an attached process. */ |
| if (current_inferior ()->attach_flag) |
| return NULL; |
| |
| /* Find the program interpreter. */ |
| interp_name = find_program_interpreter (); |
| if (!interp_name) |
| return NULL; |
| |
| /* Create a bfd for the interpreter. */ |
| gdb_bfd_ref_ptr dyld_bfd (gdb_bfd_open (interp_name, gnutarget)); |
| if (dyld_bfd != NULL) |
| { |
| gdb_bfd_ref_ptr sub |
| (gdb_bfd_mach_o_fat_extract (dyld_bfd.get (), bfd_object, |
| gdbarch_bfd_arch_info (target_gdbarch ()))); |
| dyld_bfd = sub; |
| } |
| return dyld_bfd; |
| } |
| |
| /* Extract dyld_all_image_addr when the process was just created, assuming the |
| current PC is at the entry of the dynamic linker. */ |
| |
| static void |
| darwin_solib_get_all_image_info_addr_at_init (struct darwin_info *info) |
| { |
| CORE_ADDR load_addr = 0; |
| gdb_bfd_ref_ptr dyld_bfd = darwin_get_dyld_bfd (); |
| |
| if (dyld_bfd == NULL) |
| return; |
| |
| /* We find the dynamic linker's base address by examining |
| the current pc (which should point at the entry point for the |
| dynamic linker) and subtracting the offset of the entry point. */ |
| load_addr = (regcache_read_pc (get_current_regcache ()) |
| - bfd_get_start_address (dyld_bfd.get ())); |
| |
| /* Now try to set a breakpoint in the dynamic linker. */ |
| info->all_image_addr = |
| lookup_symbol_from_bfd (dyld_bfd.get (), "_dyld_all_image_infos"); |
| |
| if (info->all_image_addr == 0) |
| return; |
| |
| info->all_image_addr += load_addr; |
| } |
| |
| /* Extract dyld_all_image_addr reading it from |
| TARGET_OBJECT_DARWIN_DYLD_INFO. */ |
| |
| static void |
| darwin_solib_read_all_image_info_addr (struct darwin_info *info) |
| { |
| gdb_byte buf[8]; |
| LONGEST len; |
| struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr; |
| |
| /* Sanity check. */ |
| if (TYPE_LENGTH (ptr_type) > sizeof (buf)) |
| return; |
| |
| len = target_read (current_inferior ()->top_target (), |
| TARGET_OBJECT_DARWIN_DYLD_INFO, |
| NULL, buf, 0, TYPE_LENGTH (ptr_type)); |
| if (len <= 0) |
| return; |
| |
| /* The use of BIG endian is intended, as BUF is a raw stream of bytes. This |
| makes the support of remote protocol easier. */ |
| info->all_image_addr = extract_unsigned_integer (buf, len, BFD_ENDIAN_BIG); |
| } |
| |
| /* Shared library startup support. See documentation in solib-svr4.c. */ |
| |
| static void |
| darwin_solib_create_inferior_hook (int from_tty) |
| { |
| /* Everything below only makes sense if we have a running inferior. */ |
| if (!target_has_execution ()) |
| return; |
| |
| struct darwin_info *info = get_darwin_info (); |
| CORE_ADDR load_addr; |
| |
| info->all_image_addr = 0; |
| |
| darwin_solib_read_all_image_info_addr (info); |
| |
| if (info->all_image_addr == 0) |
| darwin_solib_get_all_image_info_addr_at_init (info); |
| |
| if (info->all_image_addr == 0) |
| return; |
| |
| darwin_load_image_infos (info); |
| |
| if (!darwin_dyld_version_ok (info)) |
| { |
| warning (_("unhandled dyld version (%d)"), info->all_image.version); |
| return; |
| } |
| |
| if (info->all_image.count != 0) |
| { |
| /* Possible relocate the main executable (PIE). */ |
| load_addr = darwin_read_exec_load_addr_from_dyld (info); |
| } |
| else |
| { |
| /* Possible issue: |
| Do not break on the notifier if dyld is not initialized (deduced from |
| count == 0). In that case, dyld hasn't relocated itself and the |
| notifier may point to a wrong address. */ |
| |
| load_addr = darwin_read_exec_load_addr_at_init (info); |
| } |
| |
| if (load_addr != 0 && current_program_space->symfile_object_file != NULL) |
| { |
| CORE_ADDR vmaddr; |
| |
| /* Find the base address of the executable. */ |
| vmaddr = bfd_mach_o_get_base_address (current_program_space->exec_bfd ()); |
| |
| /* Relocate. */ |
| if (vmaddr != load_addr) |
| objfile_rebase (current_program_space->symfile_object_file, |
| load_addr - vmaddr); |
| } |
| |
| /* Set solib notifier (to reload list of shared libraries). */ |
| CORE_ADDR notifier = info->all_image.notifier; |
| |
| if (info->all_image.count == 0) |
| { |
| /* Dyld hasn't yet relocated itself, so the notifier address may |
| be incorrect (as it has to be relocated). */ |
| CORE_ADDR start |
| = bfd_get_start_address (current_program_space->exec_bfd ()); |
| if (start == 0) |
| notifier = 0; |
| else |
| { |
| gdb_bfd_ref_ptr dyld_bfd = darwin_get_dyld_bfd (); |
| if (dyld_bfd != NULL) |
| { |
| CORE_ADDR dyld_bfd_start_address; |
| CORE_ADDR dyld_relocated_base_address; |
| CORE_ADDR pc; |
| |
| dyld_bfd_start_address = bfd_get_start_address (dyld_bfd.get()); |
| |
| /* We find the dynamic linker's base address by examining |
| the current pc (which should point at the entry point |
| for the dynamic linker) and subtracting the offset of |
| the entry point. */ |
| |
| pc = regcache_read_pc (get_current_regcache ()); |
| dyld_relocated_base_address = pc - dyld_bfd_start_address; |
| |
| /* We get the proper notifier relocated address by |
| adding the dyld relocated base address to the current |
| notifier offset value. */ |
| |
| notifier += dyld_relocated_base_address; |
| } |
| } |
| } |
| |
| /* Add the breakpoint which is hit by dyld when the list of solib is |
| modified. */ |
| if (notifier != 0) |
| create_solib_event_breakpoint (target_gdbarch (), notifier); |
| } |
| |
| static void |
| darwin_clear_solib (void) |
| { |
| struct darwin_info *info = get_darwin_info (); |
| |
| info->all_image_addr = 0; |
| info->all_image.version = 0; |
| } |
| |
| static void |
| darwin_free_so (struct so_list *so) |
| { |
| lm_info_darwin *li = (lm_info_darwin *) so->lm_info; |
| |
| delete li; |
| } |
| |
| /* The section table is built from bfd sections using bfd VMAs. |
| Relocate these VMAs according to solib info. */ |
| |
| static void |
| darwin_relocate_section_addresses (struct so_list *so, |
| struct target_section *sec) |
| { |
| lm_info_darwin *li = (lm_info_darwin *) so->lm_info; |
| |
| sec->addr += li->lm_addr; |
| sec->endaddr += li->lm_addr; |
| |
| /* Best effort to set addr_high/addr_low. This is used only by |
| 'info sharedlibary'. */ |
| if (so->addr_high == 0) |
| { |
| so->addr_low = sec->addr; |
| so->addr_high = sec->endaddr; |
| } |
| if (sec->endaddr > so->addr_high) |
| so->addr_high = sec->endaddr; |
| if (sec->addr < so->addr_low) |
| so->addr_low = sec->addr; |
| } |
| |
| static gdb_bfd_ref_ptr |
| darwin_bfd_open (const char *pathname) |
| { |
| int found_file; |
| |
| /* Search for shared library file. */ |
| gdb::unique_xmalloc_ptr<char> found_pathname |
| = solib_find (pathname, &found_file); |
| if (found_pathname == NULL) |
| perror_with_name (pathname); |
| |
| /* Open bfd for shared library. */ |
| gdb_bfd_ref_ptr abfd (solib_bfd_fopen (found_pathname.get (), found_file)); |
| |
| gdb_bfd_ref_ptr res |
| (gdb_bfd_mach_o_fat_extract (abfd.get (), bfd_object, |
| gdbarch_bfd_arch_info (target_gdbarch ()))); |
| if (res == NULL) |
| error (_("`%s': not a shared-library: %s"), |
| bfd_get_filename (abfd.get ()), bfd_errmsg (bfd_get_error ())); |
| |
| /* The current filename for fat-binary BFDs is a name generated |
| by BFD, usually a string containing the name of the architecture. |
| Reset its value to the actual filename. */ |
| bfd_set_filename (res.get (), pathname); |
| |
| return res; |
| } |
| |
| struct target_so_ops darwin_so_ops; |
| |
| void _initialize_darwin_solib (); |
| void |
| _initialize_darwin_solib () |
| { |
| darwin_so_ops.relocate_section_addresses = darwin_relocate_section_addresses; |
| darwin_so_ops.free_so = darwin_free_so; |
| darwin_so_ops.clear_solib = darwin_clear_solib; |
| darwin_so_ops.solib_create_inferior_hook = darwin_solib_create_inferior_hook; |
| darwin_so_ops.current_sos = darwin_current_sos; |
| darwin_so_ops.open_symbol_file_object = open_symbol_file_object; |
| darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code; |
| darwin_so_ops.bfd_open = darwin_bfd_open; |
| } |