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 collections
6import logging
7import os
8import tempfile
9from autotest_lib.client.common_lib import error
10from autotest_lib.server import test
11from autotest_lib.server import utils
12
13
14class brillo_HWRandom(test.test):
15    """Tests that /dev/hw_random is present and passes basic tests."""
16    version = 1
17
18    # Basic info for a dieharder test.
19    TestInfo = collections.namedtuple('TestInfo', 'number custom_args')
20
21    # Basic results of a dieharder test.
22    TestResult = collections.namedtuple('TestResult', 'test_name assessment')
23
24    # Results of a test suite run.
25    TestSuiteResult = collections.namedtuple('TestSuiteResult',
26                                             'num_weak num_failed full_output')
27
28    # A list of dieharder tests that can be reasonably constrained to run within
29    # a sample space of <= 10MB, and the arguments to constrain them. These have
30    # been applied somewhat naively and over time these can be tweaked if a test
31    # has a problematic failure rate. In general, since there is only so much
32    # that can be done within the constraints these tests should be viewed as a
33    # sanity check and not as a measure of entropy quality. If a hardware RNG
34    # repeatedly fails this test, it has a big problem and should not be used.
35    _TEST_LIST = [
36        TestInfo(number=0, custom_args=['-p', '50']),
37        TestInfo(number=1, custom_args=['-p', '50', '-t', '50000']),
38        TestInfo(number=2, custom_args=['-p', '50', '-t', '1000']),
39        TestInfo(number=3, custom_args=['-p', '50', '-t', '5000']),
40        TestInfo(number=8, custom_args=['-p', '40']),
41        TestInfo(number=10, custom_args=[]),
42        TestInfo(number=11, custom_args=[]),
43        TestInfo(number=12, custom_args=[]),
44        TestInfo(number=15, custom_args=['-p', '50', '-t', '50000']),
45        TestInfo(number=16, custom_args=['-p', '50', '-t', '7000']),
46        TestInfo(number=17, custom_args=['-p', '50', '-t', '20000']),
47        TestInfo(number=100, custom_args=['-p', '50', '-t', '50000']),
48        TestInfo(number=101, custom_args=['-p', '50', '-t', '50000']),
49        TestInfo(number=102, custom_args=['-p', '50', '-t', '50000']),
50        TestInfo(number=200, custom_args=['-p', '20', '-t', '20000',
51                                          '-n', '3']),
52        TestInfo(number=202, custom_args=['-p', '20', '-t', '20000']),
53        TestInfo(number=203, custom_args=['-p', '50', '-t', '50000']),
54        TestInfo(number=204, custom_args=['-p', '200']),
55        TestInfo(number=205, custom_args=['-t', '512000']),
56        TestInfo(number=206, custom_args=['-t', '40000', '-n', '64']),
57        TestInfo(number=207, custom_args=['-t', '300000']),
58        TestInfo(number=208, custom_args=['-t', '400000']),
59        TestInfo(number=209, custom_args=['-t', '2000000']),
60    ]
61
62    def _run_dieharder_test(self, input_file, test_number, custom_args=None):
63        """Runs a specific dieharder test (locally) and returns the assessment.
64
65        @param input_file: The name of the file containing the data to be tested
66        @param test_number: A dieharder test number specifying which test to run
67        @param custom_args: Optional additional arguments for the test
68
69        @returns A list of TestResult
70
71        @raise TestError: An error occurred running the test.
72        """
73        command = ['dieharder',
74                   '-g', '201',
75                   '-D', 'test_name',
76                   '-D', 'ntuple',
77                   '-D', 'assessment',
78                   '-D', '32768',  # no_whitespace
79                   '-c', ',',
80                   '-d', str(test_number),
81                   '-f', input_file]
82        if custom_args:
83            command.extend(custom_args)
84        command_result = utils.run(command)
85        if command_result.stderr != '':
86            raise error.TestError('Error running dieharder: %s' %
87                                  command_result.stderr.rstrip())
88        output = command_result.stdout.splitlines()
89        results = []
90        for line in output:
91            fields = line.split(',')
92            if len(fields) != 3:
93                raise error.TestError(
94                    'dieharder: unexpected output: %s' % line)
95            results.append(self.TestResult(
96                test_name='%s[%s]' % (fields[0], fields[1]),
97                assessment=fields[2]))
98        return results
99
100
101    def _run_all_dieharder_tests(self, input_file):
102        """Runs all the dieharder tests in _TEST_LIST, continuing on failure.
103
104        @param input_file: The name of the file containing the data to be tested
105
106        @returns TestSuiteResult
107
108        @raise TestError: An error occurred running the test.
109        """
110        weak = 0
111        failed = 0
112        full_output = 'Test Results:\n'
113        for test_info in self._TEST_LIST:
114            results = self._run_dieharder_test(input_file,
115                                               test_info.number,
116                                               test_info.custom_args)
117            for test_result in results:
118                logging.info('%s: %s', test_result.test_name,
119                             test_result.assessment)
120                full_output += '  %s: %s\n' % test_result
121                if test_result.assessment == 'WEAK':
122                    weak += 1
123                elif test_result.assessment == 'FAILED':
124                    failed += 1
125                elif test_result.assessment != 'PASSED':
126                    raise error.TestError(
127                        'Unexpected output: %s' % full_output)
128        logging.info('Total: %d, Weak: %d, Failed: %d',
129                     len(self._TEST_LIST), weak, failed)
130        return self.TestSuiteResult(weak, failed, full_output)
131
132    def run_once(self, host=None):
133        """Runs the test.
134
135        @param host: A host object representing the DUT.
136
137        @raise TestError: An error occurred running the test.
138        @raise TestFail: The test ran without error but failed.
139        """
140        # Grab 10MB of data from /dev/hw_random.
141        dut_file = '/data/local/tmp/hw_random_output'
142        host.run('dd count=20480 if=/dev/hw_random of=%s' % dut_file)
143        with tempfile.NamedTemporaryFile() as local_file:
144            host.get_file(dut_file, local_file.name)
145            output_size = os.stat(local_file.name).st_size
146            if output_size != 0xA00000:
147                raise error.TestError(
148                    'Unexpected output length: %d (expecting %d)',
149                    output_size, 0xA00000)
150            # Run the data through each test (even if one fails).
151            result = self._run_all_dieharder_tests(local_file.name)
152            if result.num_failed > 0 or result.num_weak > 5:
153                raise error.TestFail(result.full_output)
154