1# Copyright 2016 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import logging, re
6
7# http://docs.python.org/2/library/errno.html
8import errno
9
10from autotest_lib.client.common_lib import error
11
12class WatchdogTester(object):
13    """Helper class to perform various watchdog tests."""
14
15    WD_DEV = '/dev/watchdog'
16
17    def _exists_on_client(self):
18        return self._client.run('test -c "%s"' % self.WD_DEV,
19                                ignore_status=True).exit_status == 0
20
21    # If daisydog is running, stop it so we can use /dev/watchdog
22    def _stop_daemon(self):
23        """If running, stop daisydog so we can use /dev/watchdog."""
24        self._client.run('stop daisydog', ignore_status=True)
25
26    def _start_daemon(self):
27        self._client.run('start daisydog', ignore_status=True)
28
29    def _query_hw_interval(self):
30        """Check how long the hardware interval is."""
31        output = self._client.run('daisydog -c').stdout
32        secs = re.findall(r'HW watchdog interval is (\d*) seconds', output)[0]
33        return int(secs)
34
35    def __init__(self, client):
36        self._client = client
37        self._supported = self._exists_on_client()
38
39    def is_supported(self):
40        return self._supported
41
42    def __enter__(self):
43        self._stop_daemon()
44        self._hw_interval = self._query_hw_interval()
45
46    def trigger_watchdog(self, timeout=60):
47        """
48        Trigger a watchdog reset by opening the watchdog device but not petting
49        it. Will ensure the device goes down and comes back up again.
50        """
51
52        try:
53            self._client.run('echo "z" > %s' % self.WD_DEV)
54        except error.AutoservRunError, e:
55            raise error.TestError('write to %s failed (%s)' %
56                                  (self.WD_DEV, errno.errorcode[e.errno]))
57
58        logging.info("WatchdogHelper: tickled watchdog on %s (%ds to reboot)",
59                     self._client.hostname, self._hw_interval)
60
61        # machine should became unpingable after lockup
62        # ...give 5 seconds slack...
63        wait_down = self._hw_interval + 5
64        if not self._client.wait_down(timeout=wait_down):
65            raise error.TestError('machine should be unpingable '
66                                  'within %d seconds' % wait_down)
67
68        # make sure the machine comes back,
69        # DHCP can take up to 45 seconds in odd cases.
70        if not self._client.wait_up(timeout=timeout):
71            raise error.TestError('machine did not reboot/ping within '
72                                  '%d seconds of HW reset' % timeout)
73
74    def __exit__(self, exception, value, traceback):
75        self._start_daemon()
76