linux-kernel-module-cheat/rungdb

#!/usr/bin/env python3

import os
import shlex
import sys
import signal
import subprocess

import common

defaults = {
    'after': '',
    'before': '',
    'no_continue': False,
    'kgdb': False,
    'no_lxsymbols': False,
    'break_at': None,
}

def main(args, extra_args=None):
    '''
    :param args: argparse parse_argument() output. Must contain all the common options,
                 but does not need GDB specific ones.
    :type args: argparse.Namespace

    :param extra_args: extra arguments to be added to args
    :type extra_args: Dict[str,Any]

    :return: GDB exit status
    :rtype: int
    '''
    global defaults
    args = common.resolve_args(defaults, args, extra_args)
    after = shlex.split(args.after)
    before = shlex.split(args.before)
    if args.no_lxsymbols:
        lx_symbols = []
    else:
        lx_symbols = ['-ex', 'lx-symbols ../kernel_modules-1.0/']
    if args.break_at is not None:
        break_at = ['-ex', 'break {}'.format(args.break_at)]
    else:
        break_at = []
    cmd = (
        [
            os.path.join(common.host_bin_dir,
            '{}-linux-gdb'.format(args.arch))
        ] +
        before +
        [
            '-q',
            '-ex', 'add-auto-load-safe-path {}'.format(common.linux_variant_dir),
            '-ex', 'file {}'.format(common.vmlinux),
            '-ex', 'target remote localhost:{}'.format(common.gdb_port),
        ]
    )
    if not args.kgdb:
        cmd.extend(break_at)
    if not args.no_continue:
        # ## lx-symbols
        #
        # ### lx-symbols after continue
        #
        # lx symbols must be run after continue.
        #
        # running it immediately after the connect on the bootloader leads to failure,
        # likely because kernel structure on which it depends are not yet available.
        #
        # With this setup, continue runs, and lx-symbols only runs when a break happens,
        # either by hitting the breakpoint, or by entering Ctrl + C.
        #
        # Sure, if the user sets a break on a raw address of the bootloader,
        # problems will still arise, but let's think about that some other time.
        #
        # ### lx-symbols autoload
        #
        # The lx-symbols commands gets loaded through the file vmlinux-gdb.py
        # which gets put on the kernel build root when python debugging scripts are enabled.
        cmd.extend(['-ex', 'continue'] + lx_symbols)
    cmd.extend(after)
    return common.run_cmd(cmd, cmd_file=os.path.join(common.run_dir, 'rungdb.sh'), cwd=common.linux_variant_dir)

if __name__ == '__main__':
    parser = common.get_argparse(argparse_args={'description': 'Connect with GDB to an emulator to debug Linux itself'})
    parser.add_argument(
        '-A', '--after', default=defaults['after'],
        help='Pass extra arguments to GDB, to be appended after all other arguments'
    )
    parser.add_argument(
        '-b', '--before', default=defaults['before'],
        help='Pass extra arguments to GDB to be prepended before any of the arguments passed by this script'
    )
    parser.add_argument(
        '-C', '--no-continue', default=defaults['no_continue'], action='store_true',
        help="Don't run continue after connecting"
    )
    parser.add_argument(
        '-k', '--kgdb', default=defaults['kgdb'], action='store_true'
    )
    parser.add_argument(
        '-X', '--no-lxsymbols', default=defaults['no_lxsymbols'], action='store_true'
    )
    parser.add_argument(
        'break_at', nargs='?',
        help='Extra options to append at the end of the emulator command line'
    )
    args = common.setup(parser)
    sys.exit(main(args))