#!/usr/bin/python3
#
# Copyright (c) 2007 Canonical Ltd.
# Author: Martin Pitt <martin.pitt@ubuntu.com>
#
# 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

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))