Add GDB scripts for dynamic debugging of Win32 binaries via Wine.

This commit is contained in:
John Millikin 2022-08-23 22:22:12 +09:00
parent 92b15fed6e
commit 38eb0448b5
3 changed files with 107 additions and 0 deletions

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# A GDB command to obtain the PID of a traced process, which must be running
# on an x86 Linux host. This is primarily useful when running gdbserver.exe
# under Wine.
#
# Note that binaries linked with non-executable stacks, such as those
# created by the `-z,noexecstack` or `/NXCOMPAT` options, should replace
# `($esp-7)` with an address that will be mapped to an executable region.
# Selection of such an address is platform- and binary-specific.
define getpid-linux-i386
# MOV eax,20 [SYS_getpid]
# INT 0x80
# RET
set $linux_getpid = {int (void)}($esp-7)
set {unsigned char[8]}($linux_getpid) = {\
0xB8, 0x14, 0x00, 0x00, 0x00, \
0xCD, 0x80, \
0xC3 \
}
output $linux_getpid()
echo \n
end

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# A GDB command for fetching /proc/{pid}/maps from a remote gdbserver,
# formatted in the style of `info proc mappings`.
#
# usage: remote-proc-mappings PID
import contextlib
import os
import threading
@contextlib.contextmanager
def pipe_fds():
r_fd, w_fd = os.pipe()
r_file = os.fdopen(r_fd, mode="rb")
w_file = os.fdopen(w_fd, mode="wb")
try:
yield (r_file, w_file)
finally:
r_file.close()
w_file.close()
class ReadThread(threading.Thread):
def __init__(self, reader):
super(ReadThread, self).__init__()
self.__r = reader
self.bytes = None
def run(self):
self.bytes = bytearray(self.__r.read())
def reformat_line(raw_line):
split = raw_line.decode("utf-8").split(None, 5)
# split[0] range
# split[1] mode
# split[2] offset
# split[3] major_minor
# split[4] inode
# split[5] object name
start_addr_s, end_addr_s = split[0].split("-")
start_addr = int(start_addr_s, 16)
end_addr = int(end_addr_s, 16)
if len(split) == 6:
objfile = split[5]
else:
objfile = ""
return "0x{:X} 0x{:X} 0x{:X} 0x{:X} {} {}\n".format(
start_addr, end_addr,
end_addr - start_addr,
int(split[2], 16),
split[1],
objfile,
)
class RemoteProcMappings(gdb.Command):
def __init__(self):
super(RemoteProcMappings, self).__init__("remote-proc-mappings", gdb.COMMAND_STATUS)
def invoke(self, arg, from_tty):
argv = gdb.string_to_argv(arg)
if len(argv) != 1:
gdb.write("usage: remote-proc-mappings PID\n", gdb.STDERR)
return
remote_pid = int(argv[0])
with pipe_fds() as (r_file, w_file):
read_thread = ReadThread(reader = r_file)
read_thread.start()
maps_path = "/proc/{}/maps".format(remote_pid)
pipe_writer_path = "/dev/fd/{}".format(w_file.fileno())
gdb.execute("remote get {} {}".format(maps_path, pipe_writer_path))
w_file.close()
read_thread.join()
raw_bytes = read_thread.bytes
for raw_line in raw_bytes.split(b"\n"):
if raw_line:
gdb.write(reformat_line(raw_line))
RemoteProcMappings()

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define info proc mappings
python
remote_pid = gdb.execute("getpid-linux-i386", to_string=True).strip()
gdb.execute("remote-proc-mappings {}".format(remote_pid))
end
end