binutils-gdb/gdb/solib-darwin.c

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/* Handle Darwin shared libraries for GDB, the GNU Debugger.
Copyright (C) 2009, 2010, 2011 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_assert.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 "exceptions.h"
#include "mach-o.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 12
/* Address of structure dyld_all_image_infos in inferior. */
static CORE_ADDR dyld_all_image_addr;
/* Gdb copy of dyld_all_info_infos. */
static struct gdb_dyld_all_image_infos dyld_all_image;
/* Return non-zero if the version in dyld_all_image is known. */
static int
darwin_dyld_version_ok (void)
{
return dyld_all_image.version >= DYLD_VERSION_MIN
&& dyld_all_image.version <= DYLD_VERSION_MAX;
}
/* Read dyld_all_image from inferior. */
static void
darwin_load_image_infos (void)
{
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 (dyld_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 * ptr_type->length;
gdb_assert (len <= sizeof (buf));
memset (&dyld_all_image, 0, sizeof (dyld_all_image));
/* Read structure raw bytes from target. */
if (target_read_memory (dyld_all_image_addr, buf, len))
return;
/* Extract the fields. */
dyld_all_image.version = extract_unsigned_integer (buf, 4, byte_order);
if (!darwin_dyld_version_ok ())
return;
dyld_all_image.count = extract_unsigned_integer (buf + 4, 4, byte_order);
dyld_all_image.info = extract_typed_address (buf + 8, ptr_type);
dyld_all_image.notifier = extract_typed_address
(buf + 8 + ptr_type->length, ptr_type);
}
/* Link map info to include in an allocated so_list entry. */
struct lm_info
{
/* The target location of lm. */
CORE_ADDR lm_addr;
};
struct darwin_so_list
{
/* Common field. */
struct so_list sl;
/* Darwin specific data. */
struct lm_info li;
};
/* Lookup the value for a specific symbol. */
static CORE_ADDR
lookup_symbol_from_bfd (bfd *abfd, 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 gdb_byte *
find_program_interpreter (void)
{
gdb_byte *buf = NULL;
/* If we have an exec_bfd, get the interpreter from the load commands. */
if (exec_bfd)
{
bfd_mach_o_load_command *cmd;
if (bfd_mach_o_lookup_command (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 (void *from_ttyp)
{
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;
int ptr_len = TYPE_LENGTH (ptr_type);
unsigned int image_info_size;
CORE_ADDR lm;
struct so_list *head = NULL;
struct so_list *tail = NULL;
int i;
/* Be sure image infos are loaded. */
darwin_load_image_infos ();
if (!darwin_dyld_version_ok ())
return NULL;
image_info_size = ptr_len * 3;
/* Read infos for each solib.
This first entry is ignored as this is the executable itself. */
for (i = 1; i < dyld_all_image.count; i++)
{
CORE_ADDR info = dyld_all_image.info + i * image_info_size;
char buf[image_info_size];
CORE_ADDR load_addr;
CORE_ADDR path_addr;
char *file_path;
int errcode;
struct darwin_so_list *dnew;
struct so_list *new;
struct cleanup *old_chain;
/* Read image info from inferior. */
if (target_read_memory (info, buf, image_info_size))
break;
load_addr = extract_typed_address (buf, ptr_type);
path_addr = extract_typed_address (buf + ptr_len, ptr_type);
target_read_string (path_addr, &file_path,
SO_NAME_MAX_PATH_SIZE - 1, &errcode);
if (errcode)
break;
/* Create and fill the new so_list element. */
dnew = XZALLOC (struct darwin_so_list);
new = &dnew->sl;
old_chain = make_cleanup (xfree, dnew);
new->lm_info = &dnew->li;
strncpy (new->so_name, file_path, SO_NAME_MAX_PATH_SIZE - 1);
new->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';
strcpy (new->so_original_name, new->so_name);
xfree (file_path);
new->lm_info->lm_addr = load_addr;
if (head == NULL)
head = new;
else
tail->next = new;
tail = new;
discard_cleanups (old_chain);
}
return head;
}
/* Return 1 if PC lies in the dynamic symbol resolution code of the
run time loader. */
int
darwin_in_dynsym_resolve_code (CORE_ADDR pc)
{
return 0;
}
/* No special symbol handling. */
static void
darwin_special_symbol_handling (void)
{
}
/* 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 (void)
{
gdb_byte *interp_name;
CORE_ADDR load_addr = 0;
bfd *dyld_bfd = NULL;
/* This method doesn't work with an attached process. */
if (current_inferior ()->attach_flag)
return;
/* Find the program interpreter. */
interp_name = find_program_interpreter ();
if (!interp_name)
return;
/* Create a bfd for the interpreter. */
dyld_bfd = bfd_openr (interp_name, gnutarget);
if (dyld_bfd)
{
bfd *sub;
sub = bfd_mach_o_fat_extract (dyld_bfd, bfd_object,
gdbarch_bfd_arch_info (target_gdbarch));
if (sub)
dyld_bfd = sub;
else
{
bfd_close (dyld_bfd);
dyld_bfd = NULL;
}
}
if (!dyld_bfd)
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));
/* Now try to set a breakpoint in the dynamic linker. */
dyld_all_image_addr =
lookup_symbol_from_bfd (dyld_bfd, "_dyld_all_image_infos");
bfd_close (dyld_bfd);
if (dyld_all_image_addr == 0)
return;
dyld_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 (void)
{
gdb_byte buf[8 + 8 + 4];
LONGEST len;
enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
len = target_read (&current_target, TARGET_OBJECT_DARWIN_DYLD_INFO, NULL,
buf, 0, sizeof (buf));
if (len != sizeof (buf))
return;
dyld_all_image_addr = extract_unsigned_integer (buf, 8, byte_order);
}
/* Shared library startup support. See documentation in solib-svr4.c. */
static void
darwin_solib_create_inferior_hook (int from_tty)
{
dyld_all_image_addr = 0;
darwin_solib_read_all_image_info_addr ();
if (dyld_all_image_addr == 0)
darwin_solib_get_all_image_info_addr_at_init ();
if (dyld_all_image_addr == 0)
return;
darwin_load_image_infos ();
if (darwin_dyld_version_ok ())
create_solib_event_breakpoint (target_gdbarch, dyld_all_image.notifier);
}
static void
darwin_clear_solib (void)
{
dyld_all_image_addr = 0;
dyld_all_image.version = 0;
}
static void
darwin_free_so (struct so_list *so)
{
}
/* 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)
{
sec->addr += so->lm_info->lm_addr;
sec->endaddr += so->lm_info->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 struct symbol *
darwin_lookup_lib_symbol (const struct objfile *objfile,
const char *name,
const domain_enum domain)
{
return NULL;
}
static bfd *
darwin_bfd_open (char *pathname)
{
char *found_pathname;
int found_file;
bfd *abfd;
bfd *res;
/* Search for shared library file. */
found_pathname = solib_find (pathname, &found_file);
if (found_pathname == NULL)
perror_with_name (pathname);
/* Open bfd for shared library. */
abfd = solib_bfd_fopen (found_pathname, found_file);
res = bfd_mach_o_fat_extract (abfd, bfd_object,
gdbarch_bfd_arch_info (target_gdbarch));
if (!res)
{
bfd_close (abfd);
make_cleanup (xfree, found_pathname);
error (_("`%s': not a shared-library: %s"),
found_pathname, bfd_errmsg (bfd_get_error ()));
}
return res;
}
struct target_so_ops darwin_so_ops;
void
_initialize_darwin_solib (void)
{
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.special_symbol_handling = darwin_special_symbol_handling;
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.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
darwin_so_ops.bfd_open = darwin_bfd_open;
}