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- /* Handle Darwin shared libraries for GDB, the GNU Debugger.
- Copyright (C) 2009-2022 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;
- }
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