#!/usr/bin/python3
#
# Copyright (c) 2007 Canonical Ltd.
# Author: Martin Pitt <[email protected]>
#
# 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 2 of the License, or (at your
# option) any later version.  See http://www.gnu.org/copyleft/gpl.html for
# the full text of the license.

"""Collect information about a kernel oops."""

import glob
import os
import re

import apport
import apport.fileutils


def main() -> None:
    """Collect information about a kernel oops."""
    pr = apport.Report("KernelCrash")
    package = apport.packaging.get_kernel_package()
    pr.add_package(package)

    pr.add_os_info()

    vmcore_path = os.path.join(apport.fileutils.report_dir, "vmcore")
    # only accept plain files here, not symlinks; otherwise we might recursively
    # include the report, or similar DoS attacks
    if os.path.exists(f"{vmcore_path}.log"):
        try:
            log_fd = os.open(f"{vmcore_path}.log", os.O_RDONLY | os.O_NOFOLLOW)
            pr["VmCoreLog"] = (os.fdopen(log_fd, "rb"),)
            os.unlink(f"{vmcore_path}.log")
        except OSError as error:
            apport.fatal("Cannot open vmcore log: %s", str(error))

    if os.path.exists(vmcore_path):
        try:
            core_fd = os.open(vmcore_path, os.O_RDONLY | os.O_NOFOLLOW)
            pr["VmCore"] = (os.fdopen(core_fd, "rb"),)
            with apport.fileutils.make_report_file(pr) as f:
                pr.write(f)
        except OSError as error:
            apport.fatal("Cannot create report: %s", str(error))

        try:
            os.unlink(vmcore_path)
        except OSError:
            pass  # huh, already gone?
    else:
        # check for kdump-tools generated dmesg in timestamped dir
        for dmesg_file in glob.glob(
            os.path.join(apport.fileutils.report_dir, "*", "dmesg.*")
        ):
            timedir = os.path.dirname(dmesg_file)
            timestamp = os.path.basename(timedir)
            if re.match("^[0-9]{12}$", timestamp):
                # we require the containing dir to be owned by root, to avoid users
                # creating a symlink to someplace else and disclosing data; we just
                # compare against euid here so that we can test this as non-root
                if os.lstat(timedir).st_uid != os.geteuid():
                    apport.fatal("%s has unsafe permissions, ignoring", timedir)
                report_name = f"{package}-{timestamp}.crash"
                try:
                    crash_report = os.path.join(
                        apport.fileutils.report_dir, report_name
                    )
                    dmesg_fd = os.open(dmesg_file, os.O_RDONLY | os.O_NOFOLLOW)
                    pr["VmCoreDmesg"] = (os.fdopen(dmesg_fd, "rb"),)
                    with open(crash_report, "xb") as f:
                        pr.write(f)
                except OSError as error:
                    apport.fatal("Cannot create report: %s", str(error))


if __name__ == "__main__":
    main()