zfs/tests/test-runner/bin/test-runner.py.in

#!/usr/bin/env @PYTHON_SHEBANG@

#
# This file and its contents are supplied under the terms of the
# Common Development and Distribution License ("CDDL"), version 1.0.
# You may only use this file in accordance with the terms of version
# 1.0 of the CDDL.
#
# A full copy of the text of the CDDL should have accompanied this
# source.  A copy of the CDDL is also available via the Internet at
# http://www.illumos.org/license/CDDL.
#

#
# Copyright (c) 2012, 2018 by Delphix. All rights reserved.
# Copyright (c) 2019 Datto Inc.
#
# This script must remain compatible with Python 3.6+.
#

import os
import sys
import ctypes
import re
import configparser

from datetime import datetime
from optparse import OptionParser
from pwd import getpwnam
from pwd import getpwuid
from select import select
from subprocess import PIPE
from subprocess import Popen
from subprocess import check_output
from threading import Timer
from time import time, CLOCK_MONOTONIC

BASEDIR = '/var/tmp/test_results'
TESTDIR = '/usr/share/zfs/'
KMEMLEAK_FILE = '/sys/kernel/debug/kmemleak'
KILL = 'kill'
TRUE = 'true'
SUDO = 'sudo'
LOG_FILE = 'LOG_FILE'
LOG_OUT = 'LOG_OUT'
LOG_ERR = 'LOG_ERR'
LOG_FILE_OBJ = None


class timespec(ctypes.Structure):
    _fields_ = [
        ('tv_sec', ctypes.c_long),
        ('tv_nsec', ctypes.c_long)
    ]


librt = ctypes.CDLL('librt.so.1', use_errno=True)
clock_gettime = librt.clock_gettime
clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)]


def monotonic_time():
    t = timespec()
    if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) != 0:
        errno_ = ctypes.get_errno()
        raise OSError(errno_, os.strerror(errno_))
    return t.tv_sec + t.tv_nsec * 1e-9


class Result(object):
    total = 0
    runresults = {'PASS': 0, 'FAIL': 0, 'SKIP': 0, 'KILLED': 0, 'RERAN': 0}

    def __init__(self):
        self.starttime = None
        self.returncode = None
        self.runtime = ''
        self.stdout = []
        self.stderr = []
        self.kmemleak = ''
        self.result = ''

    def done(self, proc, killed, reran):
        """
        Finalize the results of this Cmd.
        """
        Result.total += 1
        m, s = divmod(monotonic_time() - self.starttime, 60)
        self.runtime = '%02d:%02d' % (m, s)
        self.returncode = proc.returncode
        if reran is True:
            Result.runresults['RERAN'] += 1
        if killed:
            self.result = 'KILLED'
            Result.runresults['KILLED'] += 1
        elif len(self.kmemleak) > 0:
            self.result = 'FAIL'
            Result.runresults['FAIL'] += 1
        elif self.returncode == 0:
            self.result = 'PASS'
            Result.runresults['PASS'] += 1
        elif self.returncode == 4:
            self.result = 'SKIP'
            Result.runresults['SKIP'] += 1
        elif self.returncode != 0:
            self.result = 'FAIL'
            Result.runresults['FAIL'] += 1


class Output(object):
    """
    This class is a slightly modified version of the 'Stream' class found
    here: http://goo.gl/aSGfv
    """
    def __init__(self, stream):
        self.stream = stream
        self._buf = b''
        self.lines = []

    def fileno(self):
        return self.stream.fileno()

    def read(self, drain=0):
        """
        Read from the file descriptor. If 'drain' set, read until EOF.
        """
        while self._read() is not None:
            if not drain:
                break

    def _read(self):
        """
        Read up to 4k of data from this output stream. Collect the output
        up to the last newline, and append it to any leftover data from a
        previous call. The lines are stored as a (timestamp, data) tuple
        for easy sorting/merging later.
        """
        fd = self.fileno()
        buf = os.read(fd, 4096)
        if not buf:
            return None
        if b'\n' not in buf:
            self._buf += buf
            return []

        buf = self._buf + buf
        tmp, rest = buf.rsplit(b'\n', 1)
        self._buf = rest
        now = datetime.now()
        rows = tmp.split(b'\n')
        self.lines += [(now, r) for r in rows]


class Cmd(object):
    verified_users = []

    def __init__(self, pathname, identifier=None, outputdir=None,
                 timeout=None, user=None, tags=None):
        self.pathname = pathname
        self.identifier = identifier
        self.outputdir = outputdir or 'BASEDIR'
        """
        The timeout for tests is measured in wall-clock time
        """
        self.timeout = timeout
        self.user = user or ''
        self.killed = False
        self.reran = None
        self.result = Result()

        if self.timeout is None:
            self.timeout = 60

    def __str__(self):
        return '''\
Pathname: %s
Identifier: %s
Outputdir: %s
Timeout: %d
User: %s
''' % (self.pathname, self.identifier, self.outputdir, self.timeout, self.user)

    def kill_cmd(self, proc, keyboard_interrupt=False):
        """
        Kill a running command due to timeout, or ^C from the keyboard. If
        sudo is required, this user was verified previously.
        """
        self.killed = True
        do_sudo = len(self.user) != 0
        signal = '-TERM'

        cmd = [SUDO, KILL, signal, str(proc.pid)]
        if not do_sudo:
            del cmd[0]

        try:
            kp = Popen(cmd)
            kp.wait()
        except Exception:
            pass

        """
        If this is not a user-initiated kill and the test has not been
        reran before we consider if the test needs to be reran:
        If the test has spent some time hibernating and didn't run the whole
        length of time before being timed out we will rerun the test.
        """
        if keyboard_interrupt is False and self.reran is None:
            runtime = monotonic_time() - self.result.starttime
            if int(self.timeout) > runtime:
                self.killed = False
                self.reran = False
                self.run(False)
                self.reran = True

    def update_cmd_privs(self, cmd, user):
        """
        If a user has been specified to run this Cmd and we're not already
        running as that user, prepend the appropriate sudo command to run
        as that user.
        """
        me = getpwuid(os.getuid())

        if not user or user is me:
            if os.path.isfile(cmd+'.ksh') and os.access(cmd+'.ksh', os.X_OK):
                cmd += '.ksh'
            if os.path.isfile(cmd+'.sh') and os.access(cmd+'.sh', os.X_OK):
                cmd += '.sh'
            return cmd

        if not os.path.isfile(cmd):
            if os.path.isfile(cmd+'.ksh') and os.access(cmd+'.ksh', os.X_OK):
                cmd += '.ksh'
            if os.path.isfile(cmd+'.sh') and os.access(cmd+'.sh', os.X_OK):
                cmd += '.sh'

        ret = '%s -E -u %s %s' % (SUDO, user, cmd)
        return ret.split(' ')

    def collect_output(self, proc):
        """
        Read from stdout/stderr as data becomes available, until the
        process is no longer running. Return the lines from the stdout and
        stderr Output objects.
        """
        out = Output(proc.stdout)
        err = Output(proc.stderr)
        res = []
        while proc.returncode is None:
            proc.poll()
            res = select([out, err], [], [], .1)
            for fd in res[0]:
                fd.read()
        for fd in res[0]:
            fd.read(drain=1)

        return out.lines, err.lines

    def run(self, dryrun, kmemleak):
        """
        This is the main function that runs each individual test.
        Determine whether or not the command requires sudo, and modify it
        if needed. Run the command, and update the result object.
        """
        if dryrun is True:
            print(self)
            return

        privcmd = self.update_cmd_privs(self.pathname, self.user)
        try:
            old = os.umask(0)
            if not os.path.isdir(self.outputdir):
                os.makedirs(self.outputdir, mode=0o777)
            os.umask(old)
        except OSError as e:
            fail('%s' % e)

        self.result.starttime = monotonic_time()

        if kmemleak:
            cmd = f'echo clear | {SUDO} tee {KMEMLEAK_FILE}'
            check_output(cmd, shell=True)

        proc = Popen(privcmd, stdout=PIPE, stderr=PIPE)
        # Allow a special timeout value of 0 to mean infinity
        if int(self.timeout) == 0:
            self.timeout = sys.maxsize
        t = Timer(int(self.timeout), self.kill_cmd, [proc])

        try:
            t.start()
            self.result.stdout, self.result.stderr = self.collect_output(proc)

            if kmemleak:
                cmd = f'echo scan | {SUDO} tee {KMEMLEAK_FILE}'
                check_output(cmd, shell=True)
                cmd = f'{SUDO} cat {KMEMLEAK_FILE}'
                self.result.kmemleak = check_output(cmd, shell=True)
        except KeyboardInterrupt:
            self.kill_cmd(proc, True)
            fail('\nRun terminated at user request.')
        finally:
            t.cancel()

        if self.reran is not False:
            self.result.done(proc, self.killed, self.reran)

    def skip(self):
        """
        Initialize enough of the test result that we can log a skipped
        command.
        """
        Result.total += 1
        Result.runresults['SKIP'] += 1
        self.result.stdout = self.result.stderr = []
        self.result.starttime = monotonic_time()
        m, s = divmod(monotonic_time() - self.result.starttime, 60)
        self.result.runtime = '%02d:%02d' % (m, s)
        self.result.result = 'SKIP'

    def log(self, options, suppress_console=False):
        """
        This function is responsible for writing all output. This includes
        the console output, the logfile of all results (with timestamped
        merged stdout and stderr), and for each test, the unmodified
        stdout/stderr/merged in its own file.
        """

        logname = getpwuid(os.getuid()).pw_name
        rer = ''
        if self.reran is True:
            rer = ' (RERAN)'
        user = ' (run as %s)' % (self.user if len(self.user) else logname)
        if self.identifier:
            msga = 'Test (%s): %s%s ' % (self.identifier, self.pathname, user)
        else:
            msga = 'Test: %s%s ' % (self.pathname, user)
        msgb = '[%s] [%s]%s\n' % (self.result.runtime, self.result.result, rer)
        pad = ' ' * (80 - (len(msga) + len(msgb)))
        result_line = msga + pad + msgb

        # The result line is always written to the log file. If -q was
        # specified only failures are written to the console, otherwise
        # the result line is written to the console. The console output
        # may be suppressed by calling log() with suppress_console=True.
        write_log(bytearray(result_line, encoding='utf-8'), LOG_FILE)
        if not suppress_console:
            if not options.quiet:
                write_log(result_line, LOG_OUT)
            elif options.quiet and self.result.result != 'PASS':
                write_log(result_line, LOG_OUT)

        lines = sorted(self.result.stdout + self.result.stderr,
                       key=lambda x: x[0])

        # Write timestamped output (stdout and stderr) to the logfile
        for dt, line in lines:
            timestamp = bytearray(dt.strftime("%H:%M:%S.%f ")[:11],
                                  encoding='utf-8')
            write_log(b'%s %s\n' % (timestamp, line), LOG_FILE)

        # Write the separate stdout/stderr/merged files, if the data exists
        if len(self.result.stdout):
            with open(os.path.join(self.outputdir, 'stdout'), 'wb') as out:
                for _, line in self.result.stdout:
                    os.write(out.fileno(), b'%s\n' % line)
        if len(self.result.stderr):
            with open(os.path.join(self.outputdir, 'stderr'), 'wb') as err:
                for _, line in self.result.stderr:
                    os.write(err.fileno(), b'%s\n' % line)
        if len(self.result.stdout) and len(self.result.stderr):
            with open(os.path.join(self.outputdir, 'merged'), 'wb') as merged:
                for _, line in lines:
                    os.write(merged.fileno(), b'%s\n' % line)
        if len(self.result.kmemleak):
            with open(os.path.join(self.outputdir, 'kmemleak'), 'wb') as kmem:
                kmem.write(self.result.kmemleak)


class Test(Cmd):
    props = ['outputdir', 'timeout', 'user', 'pre', 'pre_user', 'post',
             'post_user', 'failsafe', 'failsafe_user', 'tags']

    def __init__(self, pathname,
                 pre=None, pre_user=None, post=None, post_user=None,
                 failsafe=None, failsafe_user=None, tags=None, **kwargs):
        super(Test, self).__init__(pathname, **kwargs)
        self.pre = pre or ''
        self.pre_user = pre_user or ''
        self.post = post or ''
        self.post_user = post_user or ''
        self.failsafe = failsafe or ''
        self.failsafe_user = failsafe_user or ''
        self.tags = tags or []

    def __str__(self):
        post_user = pre_user = failsafe_user = ''
        if len(self.pre_user):
            pre_user = ' (as %s)' % (self.pre_user)
        if len(self.post_user):
            post_user = ' (as %s)' % (self.post_user)
        if len(self.failsafe_user):
            failsafe_user = ' (as %s)' % (self.failsafe_user)
        return '''\
Pathname: %s
Identifier: %s
Outputdir: %s
Timeout: %d
User: %s
Pre: %s%s
Post: %s%s
Failsafe: %s%s
Tags: %s
''' % (self.pathname, self.identifier, self.outputdir, self.timeout, self.user,
            self.pre, pre_user, self.post, post_user, self.failsafe,
            failsafe_user, self.tags)

    def verify(self):
        """
        Check the pre/post/failsafe scripts, user and Test. Omit the Test from
        this run if there are any problems.
        """
        files = [self.pre, self.pathname, self.post, self.failsafe]
        users = [self.pre_user, self.user, self.post_user, self.failsafe_user]

        for f in [f for f in files if len(f)]:
            if not verify_file(f):
                write_log("Warning: Test '%s' not added to this run because"
                          " it failed verification.\n" % f, LOG_ERR)
                return False

        for user in [user for user in users if len(user)]:
            if not verify_user(user):
                write_log("Not adding Test '%s' to this run.\n" %
                          self.pathname, LOG_ERR)
                return False

        return True

    def run(self, options):
        """
        Create Cmd instances for the pre/post/failsafe scripts. If the pre
        script doesn't pass, skip this Test. Run the post script regardless.
        If the Test is killed, also run the failsafe script.
        """
        odir = os.path.join(self.outputdir, os.path.basename(self.pre))
        pretest = Cmd(self.pre, identifier=self.identifier, outputdir=odir,
                      timeout=self.timeout, user=self.pre_user)
        test = Cmd(self.pathname, identifier=self.identifier,
                   outputdir=self.outputdir, timeout=self.timeout,
                   user=self.user)
        odir = os.path.join(self.outputdir, os.path.basename(self.failsafe))
        failsafe = Cmd(self.failsafe, identifier=self.identifier,
                       outputdir=odir, timeout=self.timeout,
                       user=self.failsafe_user)
        odir = os.path.join(self.outputdir, os.path.basename(self.post))
        posttest = Cmd(self.post, identifier=self.identifier, outputdir=odir,
                       timeout=self.timeout, user=self.post_user)

        cont = True
        if len(pretest.pathname):
            pretest.run(options.dryrun, False)
            cont = pretest.result.result == 'PASS'
            pretest.log(options)

        if cont:
            test.run(options.dryrun, options.kmemleak)
            if test.result.result == 'KILLED' and len(failsafe.pathname):
                failsafe.run(options.dryrun, False)
                failsafe.log(options, suppress_console=True)
        else:
            test.skip()

        test.log(options)

        if len(posttest.pathname):
            posttest.run(options.dryrun, False)
            posttest.log(options)


class TestGroup(Test):
    props = Test.props + ['tests']

    def __init__(self, pathname, tests=None, **kwargs):
        super(TestGroup, self).__init__(pathname, **kwargs)
        self.tests = tests or []

    def __str__(self):
        post_user = pre_user = failsafe_user = ''
        if len(self.pre_user):
            pre_user = ' (as %s)' % (self.pre_user)
        if len(self.post_user):
            post_user = ' (as %s)' % (self.post_user)
        if len(self.failsafe_user):
            failsafe_user = ' (as %s)' % (self.failsafe_user)
        return '''\
Pathname: %s
Identifier: %s
Outputdir: %s
Tests: %s
Timeout: %s
User: %s
Pre: %s%s
Post: %s%s
Failsafe: %s%s
Tags: %s
''' % (self.pathname, self.identifier, self.outputdir, self.tests,
            self.timeout, self.user, self.pre, pre_user, self.post, post_user,
            self.failsafe, failsafe_user, self.tags)

    def filter(self, keeplist):
        self.tests = [x for x in self.tests if x in keeplist]

    def verify(self):
        """
        Check the pre/post/failsafe scripts, user and tests in this TestGroup.
        Omit the TestGroup entirely, or simply delete the relevant tests in the
        group, if that's all that's required.
        """
        # If the pre/post/failsafe scripts are relative pathnames, convert to
        # absolute, so they stand a chance of passing verification.
        if len(self.pre) and not os.path.isabs(self.pre):
            self.pre = os.path.join(self.pathname, self.pre)
        if len(self.post) and not os.path.isabs(self.post):
            self.post = os.path.join(self.pathname, self.post)
        if len(self.failsafe) and not os.path.isabs(self.failsafe):
            self.post = os.path.join(self.pathname, self.post)

        auxfiles = [self.pre, self.post, self.failsafe]
        users = [self.pre_user, self.user, self.post_user, self.failsafe_user]

        for f in [f for f in auxfiles if len(f)]:
            if f != self.failsafe and self.pathname != os.path.dirname(f):
                write_log("Warning: TestGroup '%s' not added to this run. "
                          "Auxiliary script '%s' exists in a different "
                          "directory.\n" % (self.pathname, f), LOG_ERR)
                return False

            if not verify_file(f):
                write_log("Warning: TestGroup '%s' not added to this run. "
                          "Auxiliary script '%s' failed verification.\n" %
                          (self.pathname, f), LOG_ERR)
                return False

        for user in [user for user in users if len(user)]:
            if not verify_user(user):
                write_log("Not adding TestGroup '%s' to this run.\n" %
                          self.pathname, LOG_ERR)
                return False

        # If one of the tests is invalid, delete it, log it, and drive on.
        for test in self.tests:
            if not verify_file(os.path.join(self.pathname, test)):
                del self.tests[self.tests.index(test)]
                write_log("Warning: Test '%s' removed from TestGroup '%s' "
                          "because it failed verification.\n" %
                          (test, self.pathname), LOG_ERR)

        return len(self.tests) != 0

    def run(self, options):
        """
        Create Cmd instances for the pre/post/failsafe scripts. If the pre
        script doesn't pass, skip all the tests in this TestGroup. Run the
        post script regardless. Run the failsafe script when a test is killed.
        """
        # tags assigned to this test group also include the test names
        if options.tags and not set(self.tags).intersection(set(options.tags)):
            return

        odir = os.path.join(self.outputdir, os.path.basename(self.pre))
        pretest = Cmd(self.pre, outputdir=odir, timeout=self.timeout,
                      user=self.pre_user, identifier=self.identifier)
        odir = os.path.join(self.outputdir, os.path.basename(self.post))
        posttest = Cmd(self.post, outputdir=odir, timeout=self.timeout,
                       user=self.post_user, identifier=self.identifier)

        cont = True
        if len(pretest.pathname):
            pretest.run(options.dryrun, False)
            cont = pretest.result.result == 'PASS'
            pretest.log(options)

        for fname in self.tests:
            odir = os.path.join(self.outputdir, fname)
            test = Cmd(os.path.join(self.pathname, fname), outputdir=odir,
                       timeout=self.timeout, user=self.user,
                       identifier=self.identifier)
            odir = os.path.join(odir, os.path.basename(self.failsafe))
            failsafe = Cmd(self.failsafe, outputdir=odir, timeout=self.timeout,
                           user=self.failsafe_user, identifier=self.identifier)
            if cont:
                test.run(options.dryrun, options.kmemleak)
                if test.result.result == 'KILLED' and len(failsafe.pathname):
                    failsafe.run(options.dryrun, False)
                    failsafe.log(options, suppress_console=True)
            else:
                test.skip()

            test.log(options)

        if len(posttest.pathname):
            posttest.run(options.dryrun, False)
            posttest.log(options)


class TestRun(object):
    props = ['quiet', 'outputdir']

    def __init__(self, options):
        self.tests = {}
        self.testgroups = {}
        self.starttime = time()
        self.timestamp = datetime.now().strftime('%Y%m%dT%H%M%S')
        self.outputdir = os.path.join(options.outputdir, self.timestamp)
        self.setup_logging(options)
        self.defaults = [
            ('outputdir', BASEDIR),
            ('quiet', False),
            ('timeout', 60),
            ('user', ''),
            ('pre', ''),
            ('pre_user', ''),
            ('post', ''),
            ('post_user', ''),
            ('failsafe', ''),
            ('failsafe_user', ''),
            ('tags', [])
        ]

    def __str__(self):
        s = 'TestRun:\n    outputdir: %s\n' % self.outputdir
        s += 'TESTS:\n'
        for key in sorted(self.tests.keys()):
            s += '%s%s' % (self.tests[key].__str__(), '\n')
        s += 'TESTGROUPS:\n'
        for key in sorted(self.testgroups.keys()):
            s += '%s%s' % (self.testgroups[key].__str__(), '\n')
        return s

    def addtest(self, pathname, options):
        """
        Create a new Test, and apply any properties that were passed in
        from the command line. If it passes verification, add it to the
        TestRun.
        """
        test = Test(pathname)
        for prop in Test.props:
            setattr(test, prop, getattr(options, prop))

        if test.verify():
            self.tests[pathname] = test

    def addtestgroup(self, dirname, filenames, options):
        """
        Create a new TestGroup, and apply any properties that were passed
        in from the command line. If it passes verification, add it to the
        TestRun.
        """
        if dirname not in self.testgroups:
            testgroup = TestGroup(dirname)
            for prop in Test.props:
                setattr(testgroup, prop, getattr(options, prop))

            # Prevent pre/post/failsafe scripts from running as regular tests
            for f in [testgroup.pre, testgroup.post, testgroup.failsafe]:
                if f in filenames:
                    del filenames[filenames.index(f)]

            self.testgroups[dirname] = testgroup
            self.testgroups[dirname].tests = sorted(filenames)

            testgroup.verify()

    def filter(self, keeplist):
        for group in list(self.testgroups.keys()):
            if group not in keeplist:
                del self.testgroups[group]
                continue

            g = self.testgroups[group]

            if g.pre and os.path.basename(g.pre) in keeplist[group]:
                continue

            g.filter(keeplist[group])

        for test in list(self.tests.keys()):
            directory, base = os.path.split(test)
            if directory not in keeplist or base not in keeplist[directory]:
                del self.tests[test]

    def read(self, options):
        """
        Read in the specified runfiles, and apply the TestRun properties
        listed in the 'DEFAULT' section to our TestRun. Then read each
        section, and apply the appropriate properties to the Test or
        TestGroup. Properties from individual sections override those set
        in the 'DEFAULT' section. If the Test or TestGroup passes
        verification, add it to the TestRun.
        """
        config = configparser.RawConfigParser()
        parsed = config.read(options.runfiles)
        failed = options.runfiles - set(parsed)
        if len(failed):
            files = ' '.join(sorted(failed))
            fail("Couldn't read config files: %s" % files)

        for opt in TestRun.props:
            if config.has_option('DEFAULT', opt):
                setattr(self, opt, config.get('DEFAULT', opt))
        self.outputdir = os.path.join(self.outputdir, self.timestamp)

        testdir = options.testdir

        for section in config.sections():
            if 'tests' in config.options(section):
                parts = section.split(':', 1)
                sectiondir = parts[0]
                identifier = parts[1] if len(parts) == 2 else None
                if os.path.isdir(sectiondir):
                    pathname = sectiondir
                elif os.path.isdir(os.path.join(testdir, sectiondir)):
                    pathname = os.path.join(testdir, sectiondir)
                else:
                    pathname = sectiondir

                testgroup = TestGroup(os.path.abspath(pathname),
                                      identifier=identifier)
                for prop in TestGroup.props:
                    for sect in ['DEFAULT', section]:
                        if config.has_option(sect, prop):
                            if prop == 'tags':
                                setattr(testgroup, prop,
                                        eval(config.get(sect, prop)))
                            elif prop == 'failsafe':
                                failsafe = config.get(sect, prop)
                                setattr(testgroup, prop,
                                        os.path.join(testdir, failsafe))
                            else:
                                setattr(testgroup, prop,
                                        config.get(sect, prop))

                # Repopulate tests using eval to convert the string to a list
                testgroup.tests = eval(config.get(section, 'tests'))

                if testgroup.verify():
                    self.testgroups[section] = testgroup
            else:
                test = Test(section)
                for prop in Test.props:
                    for sect in ['DEFAULT', section]:
                        if config.has_option(sect, prop):
                            if prop == 'failsafe':
                                failsafe = config.get(sect, prop)
                                setattr(test, prop,
                                        os.path.join(testdir, failsafe))
                            else:
                                setattr(test, prop, config.get(sect, prop))

                if test.verify():
                    self.tests[section] = test

    def write(self, options):
        """
        Create a configuration file for editing and later use. The
        'DEFAULT' section of the config file is created from the
        properties that were specified on the command line. Tests are
        simply added as sections that inherit everything from the
        'DEFAULT' section. TestGroups are the same, except they get an
        option including all the tests to run in that directory.
        """

        defaults = dict([(prop, getattr(options, prop)) for prop, _ in
                         self.defaults])
        config = configparser.RawConfigParser(defaults)

        for test in sorted(self.tests.keys()):
            config.add_section(test)
            for prop in Test.props:
                if prop not in self.props:
                    config.set(test, prop,
                               getattr(self.tests[test], prop))

        for testgroup in sorted(self.testgroups.keys()):
            config.add_section(testgroup)
            config.set(testgroup, 'tests', self.testgroups[testgroup].tests)
            for prop in TestGroup.props:
                if prop not in self.props:
                    config.set(testgroup, prop,
                               getattr(self.testgroups[testgroup], prop))

        try:
            with open(options.template, 'w') as f:
                return config.write(f)
        except IOError:
            fail('Could not open \'%s\' for writing.' % options.template)

    def complete_outputdirs(self):
        """
        Collect all the pathnames for Tests, and TestGroups. Work
        backwards one pathname component at a time, to create a unique
        directory name in which to deposit test output. Tests will be able
        to write output files directly in the newly modified outputdir.
        TestGroups will be able to create one subdirectory per test in the
        outputdir, and are guaranteed uniqueness because a group can only
        contain files in one directory. Pre and post tests will create a
        directory rooted at the outputdir of the Test or TestGroup in
        question for their output. Failsafe scripts will create a directory
        rooted at the outputdir of each Test for their output.
        """
        done = False
        components = 0
        tmp_dict = dict(list(self.tests.items()) +
                        list(self.testgroups.items()))
        total = len(tmp_dict)
        base = self.outputdir

        while not done:
            paths = []
            components -= 1
            for testfile in list(tmp_dict.keys()):
                uniq = '/'.join(testfile.split('/')[components:]).lstrip('/')
                if uniq not in paths:
                    paths.append(uniq)
                    tmp_dict[testfile].outputdir = os.path.join(base, uniq)
                else:
                    break
            done = total == len(paths)

    def setup_logging(self, options):
        """
        This function creates the output directory and gets a file object
        for the logfile. This function must be called before write_log()
        can be used.
        """
        if options.dryrun is True:
            return

        global LOG_FILE_OBJ
        if not options.template:
            try:
                old = os.umask(0)
                os.makedirs(self.outputdir, mode=0o777)
                os.umask(old)
                filename = os.path.join(self.outputdir, 'log')
                LOG_FILE_OBJ = open(filename, buffering=0, mode='wb')
            except OSError as e:
                fail('%s' % e)

    def run(self, options):
        """
        Walk through all the Tests and TestGroups, calling run().
        """
        try:
            os.chdir(self.outputdir)
        except OSError:
            fail('Could not change to directory %s' % self.outputdir)
        # make a symlink to the output for the currently running test
        logsymlink = os.path.join(self.outputdir, '../current')
        if os.path.islink(logsymlink):
            os.unlink(logsymlink)
        if not os.path.exists(logsymlink):
            os.symlink(self.outputdir, logsymlink)
        else:
            write_log('Could not make a symlink to directory %s\n' %
                      self.outputdir, LOG_ERR)

        if options.kmemleak:
            cmd = f'echo scan=0 | {SUDO} tee {KMEMLEAK_FILE}'
            check_output(cmd, shell=True)

        iteration = 0
        while iteration < options.iterations:
            for test in sorted(self.tests.keys()):
                self.tests[test].run(options)
            for testgroup in sorted(self.testgroups.keys()):
                self.testgroups[testgroup].run(options)
            iteration += 1

    def summary(self):
        if Result.total == 0:
            return 2

        print('\nResults Summary')
        for key in list(Result.runresults.keys()):
            if Result.runresults[key] != 0:
                print('%s\t% 4d' % (key, Result.runresults[key]))

        m, s = divmod(time() - self.starttime, 60)
        h, m = divmod(m, 60)
        print('\nRunning Time:\t%02d:%02d:%02d' % (h, m, s))
        print('Percent passed:\t%.1f%%' % ((float(Result.runresults['PASS']) /
                                            float(Result.total)) * 100))
        print('Log directory:\t%s' % self.outputdir)

        if Result.runresults['FAIL'] > 0:
            return 1

        if Result.runresults['KILLED'] > 0:
            return 1

        if Result.runresults['RERAN'] > 0:
            return 3

        return 0


def write_log(msg, target):
    """
    Write the provided message to standard out, standard error or
    the logfile. If specifying LOG_FILE, then `msg` must be a bytes
    like object. This way we can still handle output from tests that
    may be in unexpected encodings.
    """
    if target == LOG_OUT:
        os.write(sys.stdout.fileno(), bytearray(msg, encoding='utf-8'))
    elif target == LOG_ERR:
        os.write(sys.stderr.fileno(), bytearray(msg, encoding='utf-8'))
    elif target == LOG_FILE:
        os.write(LOG_FILE_OBJ.fileno(), msg)
    else:
        fail('log_msg called with unknown target "%s"' % target)


def verify_file(pathname):
    """
    Verify that the supplied pathname is an executable regular file.
    """
    if os.path.isdir(pathname) or os.path.islink(pathname):
        return False

    for ext in '', '.ksh', '.sh':
        script_path = pathname + ext
        if os.path.isfile(script_path) and os.access(script_path, os.X_OK):
            return True

    return False


def verify_user(user):
    """
    Verify that the specified user exists on this system, and can execute
    sudo without being prompted for a password.
    """
    testcmd = [SUDO, '-n', '-u', user, TRUE]

    if user in Cmd.verified_users:
        return True

    try:
        getpwnam(user)
    except KeyError:
        write_log("Warning: user '%s' does not exist.\n" % user,
                  LOG_ERR)
        return False

    p = Popen(testcmd)
    p.wait()
    if p.returncode != 0:
        write_log("Warning: user '%s' cannot use passwordless sudo.\n" % user,
                  LOG_ERR)
        return False
    else:
        Cmd.verified_users.append(user)

    return True


def find_tests(testrun, options):
    """
    For the given list of pathnames, add files as Tests. For directories,
    if do_groups is True, add the directory as a TestGroup. If False,
    recursively search for executable files.
    """

    for p in sorted(options.pathnames):
        if os.path.isdir(p):
            for dirname, _, filenames in os.walk(p):
                if options.do_groups:
                    testrun.addtestgroup(dirname, filenames, options)
                else:
                    for f in sorted(filenames):
                        testrun.addtest(os.path.join(dirname, f), options)
        else:
            testrun.addtest(p, options)


def filter_tests(testrun, options):
    try:
        fh = open(options.logfile, "r")
    except Exception as e:
        fail('%s' % e)

    failed = {}
    while True:
        line = fh.readline()
        if not line:
            break
        m = re.match(r'Test: .*(tests/.*)/(\S+).*\[FAIL\]', line)
        if not m:
            continue
        group, test = m.group(1, 2)
        try:
            failed[group].append(test)
        except KeyError:
            failed[group] = [test]
    fh.close()

    testrun.filter(failed)


def fail(retstr, ret=1):
    print('%s: %s' % (sys.argv[0], retstr))
    exit(ret)


def kmemleak_cb(option, opt_str, value, parser):
    if not os.path.exists(KMEMLEAK_FILE):
        fail(f"File '{KMEMLEAK_FILE}' doesn't exist. " +
             "Enable CONFIG_DEBUG_KMEMLEAK in kernel configuration.")

    setattr(parser.values, option.dest, True)


def options_cb(option, opt_str, value, parser):
    path_options = ['outputdir', 'template', 'testdir', 'logfile']

    if opt_str in parser.rargs:
        fail('%s may only be specified once.' % opt_str)

    if option.dest == 'runfiles':
        parser.values.cmd = 'rdconfig'
        value = set(os.path.abspath(p) for p in value.split(','))
    if option.dest == 'tags':
        value = [x.strip() for x in value.split(',')]

    if option.dest in path_options:
        setattr(parser.values, option.dest, os.path.abspath(value))
    else:
        setattr(parser.values, option.dest, value)


def parse_args():
    parser = OptionParser()
    parser.add_option('-c', action='callback', callback=options_cb,
                      type='string', dest='runfiles', metavar='runfiles',
                      help='Specify tests to run via config files.')
    parser.add_option('-d', action='store_true', default=False, dest='dryrun',
                      help='Dry run. Print tests, but take no other action.')
    parser.add_option('-l', action='callback', callback=options_cb,
                      default=None, dest='logfile', metavar='logfile',
                      type='string',
                      help='Read logfile and re-run tests which failed.')
    parser.add_option('-g', action='store_true', default=False,
                      dest='do_groups', help='Make directories TestGroups.')
    parser.add_option('-o', action='callback', callback=options_cb,
                      default=BASEDIR, dest='outputdir', type='string',
                      metavar='outputdir', help='Specify an output directory.')
    parser.add_option('-i', action='callback', callback=options_cb,
                      default=TESTDIR, dest='testdir', type='string',
                      metavar='testdir', help='Specify a test directory.')
    parser.add_option('-m', action='callback', callback=kmemleak_cb,
                      default=False, dest='kmemleak',
                      help='Enable kmemleak reporting (Linux only)')
    parser.add_option('-p', action='callback', callback=options_cb,
                      default='', dest='pre', metavar='script',
                      type='string', help='Specify a pre script.')
    parser.add_option('-P', action='callback', callback=options_cb,
                      default='', dest='post', metavar='script',
                      type='string', help='Specify a post script.')
    parser.add_option('-q', action='store_true', default=False, dest='quiet',
                      help='Silence on the console during a test run.')
    parser.add_option('-s', action='callback', callback=options_cb,
                      default='', dest='failsafe', metavar='script',
                      type='string', help='Specify a failsafe script.')
    parser.add_option('-S', action='callback', callback=options_cb,
                      default='', dest='failsafe_user',
                      metavar='failsafe_user', type='string',
                      help='Specify a user to execute the failsafe script.')
    parser.add_option('-t', action='callback', callback=options_cb, default=60,
                      dest='timeout', metavar='seconds', type='int',
                      help='Timeout (in seconds) for an individual test.')
    parser.add_option('-u', action='callback', callback=options_cb,
                      default='', dest='user', metavar='user', type='string',
                      help='Specify a different user name to run as.')
    parser.add_option('-w', action='callback', callback=options_cb,
                      default=None, dest='template', metavar='template',
                      type='string', help='Create a new config file.')
    parser.add_option('-x', action='callback', callback=options_cb, default='',
                      dest='pre_user', metavar='pre_user', type='string',
                      help='Specify a user to execute the pre script.')
    parser.add_option('-X', action='callback', callback=options_cb, default='',
                      dest='post_user', metavar='post_user', type='string',
                      help='Specify a user to execute the post script.')
    parser.add_option('-T', action='callback', callback=options_cb, default='',
                      dest='tags', metavar='tags', type='string',
                      help='Specify tags to execute specific test groups.')
    parser.add_option('-I', action='callback', callback=options_cb, default=1,
                      dest='iterations', metavar='iterations', type='int',
                      help='Number of times to run the test run.')
    (options, pathnames) = parser.parse_args()

    if options.runfiles and len(pathnames):
        fail('Extraneous arguments.')

    options.pathnames = [os.path.abspath(path) for path in pathnames]

    return options


def main():
    options = parse_args()

    testrun = TestRun(options)

    if options.runfiles:
        testrun.read(options)
    else:
        find_tests(testrun, options)

    if options.logfile:
        filter_tests(testrun, options)

    if options.template:
        testrun.write(options)
        exit(0)

    testrun.complete_outputdirs()
    testrun.run(options)
    exit(testrun.summary())


if __name__ == '__main__':
    main()