#!/usr/bin/python3
#
# Collect information about processes which are still running after sending
# SIGTERM to them (which happens during computer shutdown in
# /etc/init.d/sendsigs in Debian/Ubuntu)
#
# Copyright (c) 2010 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.

import os, os.path, sys, errno, optparse

import apport, apport.fileutils, apport.hookutils


def parse_argv():
    '''Parse command line and return (options, args).'''

    optparser = optparse.OptionParser('%prog [options]')
    optparser.add_option('-o', '--omit', metavar='PID', action='append',
                         default=[], dest='blacklist',
                         help='Ignore a particular process ID (can be specified multiple times)')

    (opts, args) = optparser.parse_args()

    if len(args) != 0:
        optparser.error('This program does not take any non-option arguments.  Please see --help.')
        sys.exit(1)

    return (opts, args)


def orphaned_processes(blacklist):
    '''Yield an iterator of running process IDs.

    This excludes PIDs which do not have a valid /proc/pid/exe symlink (e. g.
    kernel processes), the PID of our own process, and everything that is
    contained in the blacklist argument.
    '''
    my_pid = os.getpid()
    my_sid = os.getsid(0)
    for d in os.listdir('/proc'):
        try:
            pid = int(d)
        except ValueError:
            continue
        if pid == 1 or pid == my_pid or d in blacklist:
            apport.warning('ignoring: %s', d)
            continue

        try:
            sid = os.getsid(pid)
        except OSError:
            # os.getsid() can fail with "No such process" if the process died
            # in the meantime
            continue

        if sid == my_sid:
            apport.warning('ignoring same sid: %s', d)
            continue

        try:
            os.readlink(os.path.join('/proc', d, 'exe'))
        except OSError as e:
            if e.errno == errno.ENOENT:
                # kernel thread or similar, silently ignore
                continue
            apport.warning('Could not read information about pid %s: %s', d, str(e))
            continue

        yield d


def do_report(pid, blacklist):
    '''Create a report for a particular PID.'''

    r = apport.Report('Bug')
    try:
        r.add_proc_info(pid)
    except (ValueError, AssertionError):
        # happens if ExecutablePath doesn't exist (any more?), ignore
        return

    r['Tags'] = 'shutdown-hang'
    r['Title'] = 'does not terminate at computer shutdown'
    if 'ExecutablePath' in r:
        r['Title'] = os.path.basename(r['ExecutablePath']) + ' ' + r['Title']
    r['Processes'] = apport.hookutils.command_output(['ps', 'aux'])
    r['InitctlList'] = apport.hookutils.command_output(['initctl', 'list'])
    if blacklist:
        r['OmitPids'] = ' '.join(blacklist)

    try:
        with apport.fileutils.make_report_file(r) as f:
            r.write(f)
    except (IOError, OSError) as e:
        apport.fatal('Cannot create report: ' + str(e))

#
# main
#

(opts, args) = parse_argv()

for p in orphaned_processes(opts.blacklist):
    do_report(p, opts.blacklist)