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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
5from __future__ import print_function
6
7import logging, re
8
9# http://docs.python.org/2/library/errno.html
10import errno
11
12from autotest_lib.client.common_lib import error
13
14class WatchdogTester(object):
15    """Helper class to perform various watchdog tests."""
16
17    WD_DEV = '/dev/watchdog'
18    DAISYDOG_PATH='/usr/sbin/daisydog'
19    def _exists_on_client(self):
20        return self._client.run('test -c "%s"' % self.WD_DEV,
21                                ignore_status=True).exit_status == 0 and \
22               self._client.run('test -x "%s"' % self.DAISYDOG_PATH,
23                                ignore_status=True).exit_status == 0
24    # If daisydog is running, stop it so we can use /dev/watchdog
25    def _stop_daemon(self):
26        """If running, stop daisydog so we can use /dev/watchdog."""
27        self._client.run('stop daisydog', ignore_status=True)
28
29    def _start_daemon(self):
30        self._client.run('start daisydog', ignore_status=True)
31
32    def _query_hw_interval(self):
33        """Check how long the hardware interval is."""
34        output = self._client.run('daisydog -c').stdout
35        secs = re.findall(r'HW watchdog interval is (\d*) seconds', output)[0]
36        return int(secs)
37
38    def __init__(self, client):
39        self._client = client
40        self._supported = self._exists_on_client()
41
42    def is_supported(self):
43        return self._supported
44
45    def __enter__(self):
46        self._stop_daemon()
47        self._hw_interval = self._query_hw_interval()
48
49    def trigger_watchdog(self, timeout=60):
50        """
51        Trigger a watchdog reset by opening the watchdog device but not petting
52        it. Will ensure the device goes down and comes back up again.
53        """
54
55        try:
56            self._client.run('echo "z" > %s' % self.WD_DEV)
57        except error.AutoservRunError as e:
58            raise error.TestError('write to %s failed (%s)' %
59                                  (self.WD_DEV, errno.errorcode[e.errno]))
60
61        logging.info("WatchdogHelper: tickled watchdog on %s (%ds to reboot)",
62                     self._client.hostname, self._hw_interval)
63
64        # machine should became unpingable after lockup
65        # ...give 5 seconds slack...
66        wait_down = self._hw_interval + 5
67        if not self._client.wait_down(timeout=wait_down):
68            raise error.TestError('machine should be unpingable '
69                                  'within %d seconds' % wait_down)
70
71        # make sure the machine comes back,
72        # DHCP can take up to 45 seconds in odd cases.
73        if not self._client.wait_up(timeout=timeout):
74            raise error.TestError('machine did not reboot/ping within '
75                                  '%d seconds of HW reset' % timeout)
76
77    def __exit__(self, exception, value, traceback):
78        self._start_daemon()
79