Re: [Qemu-devel] [PATCH V5 2/5] runner: Tool for fuzz tests execution

[M.Kustova]

On Fri, Aug 8, 2014 at 12:50 PM, Fam Zheng <address@hidden> wrote:
> On Wed, 08/06 17:12, Maria Kustova wrote:
>> The purpose of the test runner is to prepare the test environment (e.g. 
>> create
>> a work directory, a test image, etc), execute a program under test with
>> parameters, indicate a test failure if the program was killed during the test
>> execution and collect core dumps, logs and other test artifacts.
>>
>> The test runner doesn't depend on an image format or a program will be 
>> tested,
>> so it can be used with any external image generator and program under test.
>>
>> Signed-off-by: Maria Kustova <address@hidden>
>> ---
>>  tests/image-fuzzer/runner/runner.py | 405 
>> ++++++++++++++++++++++++++++++++++++
>>  1 file changed, 405 insertions(+)
>>  create mode 100755 tests/image-fuzzer/runner/runner.py
>>
>> diff --git a/tests/image-fuzzer/runner/runner.py 
>> b/tests/image-fuzzer/runner/runner.py
>> new file mode 100755
>> index 0000000..3fa7fca
>> --- /dev/null
>> +++ b/tests/image-fuzzer/runner/runner.py
>> @@ -0,0 +1,405 @@
>> +#!/usr/bin/env python
>> +
>> +# Tool for running fuzz tests
>> +#
>> +# Copyright (C) 2014 Maria Kustova <address@hidden>
>> +#
>> +# 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.
>> +#
>> +# This program is distributed in the hope that it will be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +# GNU General Public License for more details.
>> +#
>> +# You should have received a copy of the GNU General Public License
>> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> +#
>> +
>> +import sys
>> +import os
>> +import signal
>> +import subprocess
>> +import random
>> +import shutil
>> +from itertools import count
>> +import getopt
>> +import StringIO
>> +import resource
>> +
>> +try:
>> +    import json
>> +except ImportError:
>> +    try:
>> +        import simplejson as json
>> +    except ImportError:
>> +        print >>sys.stderr, \
>> +            "Warning: Module for JSON processing is not found.\n" \
>> +            "'--config' and '--command' options are not supported."
>> +
>> +# Backing file sizes in MB
>> +MAX_BACKING_FILE_SIZE = 10
>> +MIN_BACKING_FILE_SIZE = 1
>> +
>> +
>> +def multilog(msg, *output):
>> +    """ Write an object to all of specified file descriptors."""
>> +    for fd in output:
>> +        fd.write(msg)
>> +        fd.flush()
>> +
>> +
>> +def str_signal(sig):
>> +    """ Convert a numeric value of a system signal to the string one
>> +    defined by the current operational system.
>> +    """
>> +    for k, v in signal.__dict__.items():
>> +        if v == sig:
>> +            return k
>> +
>> +
>> +def run_app(fd, q_args):
>> +    """Start an application with specified arguments and return its exit 
>> code
>> +    or kill signal depending on the result of execution.
>> +    """
>> +    devnull = open('/dev/null', 'r+')
>> +    process = subprocess.Popen(q_args, stdin=devnull,
>> +                               stdout=subprocess.PIPE,
>> +                               stderr=subprocess.PIPE)
>> +    out, err = process.communicate()
>> +    fd.write(out)
>> +    fd.write(err)
>> +    return process.returncode
>> +
>> +
>> +class TestException(Exception):
>> +    """Exception for errors risen by TestEnv objects."""
>> +    pass
>> +
>> +
>> +class TestEnv(object):
>> +
>> +    """Test object.
>> +
>> +    The class sets up test environment, generates backing and test images
>> +    and executes application under tests with specified arguments and a test
>> +    image provided.
>> +
>> +    All logs are collected.
>> +
>> +    The summary log will contain short descriptions and statuses of tests in
>> +    a run.
>> +
>> +    The test log will include application (e.g. 'qemu-img') logs besides 
>> info
>> +    sent to the summary log.
>> +    """
>> +
>> +    def __init__(self, test_id, seed, work_dir, run_log,
>> +                 cleanup=True, log_all=False):
>> +        """Set test environment in a specified work directory.
>> +
>> +        Path to qemu-img and qemu-io will be retrieved from 'QEMU_IMG' and
>> +        'QEMU_IO' environment variables.
>> +        """
>> +        if seed is not None:
>> +            self.seed = seed
>> +        else:
>> +            self.seed = str(random.randint(0, sys.maxint))
>> +        random.seed(self.seed)
>> +
>> +        self.init_path = os.getcwd()
>> +        self.work_dir = work_dir
>> +        self.current_dir = os.path.join(work_dir, 'test-' + test_id)
>> +        self.qemu_img = os.environ.get('QEMU_IMG', 'qemu-img')\
>> +                                  .strip().split(' ')
>
> Nitpicking. I think split(' ') doesn't make sense, this could instead be:
>
>            self.qemu_img = [os.environ.get('QEMU_IMG', 'qemu-img').strip()]
>
> Otherwise user won't be able to pass in a QEMU_IMG path with space.
>
> Corner case, though. Otherwise looks good,

This functionality was inherited from qemu-iotests/iotests.py.
Rationale for this splitting was that environment variables can
contain call arguments as well.
Ruining paths with white spaces was a reasonable trade-off.

Maria.

>> +        self.qemu_io = os.environ.get('QEMU_IO', 'qemu-io').strip().split(' 
>> ')
>> +        self.commands = [['qemu-img', 'check', '-f', 'qcow2', '$test_img'],
>> +                         ['qemu-img', 'info', '-f', 'qcow2', '$test_img'],
>> +                         ['qemu-io', '$test_img', '-c', 'read $off $len'],
>> +                         ['qemu-io', '$test_img', '-c', 'write $off $len'],
>> +                         ['qemu-io', '$test_img', '-c',
>> +                          'aio_read $off $len'],
>> +                         ['qemu-io', '$test_img', '-c',
>> +                          'aio_write $off $len'],
>> +                         ['qemu-io', '$test_img', '-c', 'flush'],
>> +                         ['qemu-io', '$test_img', '-c',
>> +                          'discard $off $len'],
>> +                         ['qemu-io', '$test_img', '-c',
>> +                          'truncate $off']]
>> +        for fmt in ['raw', 'vmdk', 'vdi', 'cow', 'qcow2', 'file',
>> +                    'qed', 'vpc']:
>> +            self.commands.append(
>> +                ['qemu-img', 'convert', '-f', 'qcow2', '-O', fmt,
>> +                 '$test_img', 'converted_image.' + fmt])
>> +
>> +        try:
>> +            os.makedirs(self.current_dir)
>> +        except OSError, e:
>> +            print >>sys.stderr, \
>> +                "Error: The working directory '%s' cannot be used. Reason: 
>> %s"\
>> +                % (self.work_dir, e[1])
>> +            raise TestException
>> +        self.log = open(os.path.join(self.current_dir, "test.log"), "w")
>> +        self.parent_log = open(run_log, "a")
>> +        self.failed = False
>> +        self.cleanup = cleanup
>> +        self.log_all = log_all
>> +
>> +    def _create_backing_file(self):
>> +        """Create a backing file in the current directory.
>> +
>> +        Return a tuple of a backing file name and format.
>> +
>> +        Format of a backing file is randomly chosen from all formats 
>> supported
>> +        by 'qemu-img create'.
>> +        """
>> +        # All formats supported by the 'qemu-img create' command.
>> +        backing_file_fmt = random.choice(['raw', 'vmdk', 'vdi', 'cow', 
>> 'qcow2',
>> +                                          'file', 'qed', 'vpc'])
>> +        backing_file_name = 'backing_img.' + backing_file_fmt
>> +        backing_file_size = random.randint(MIN_BACKING_FILE_SIZE,
>> +                                           MAX_BACKING_FILE_SIZE) * (1 << 
>> 20)
>> +        cmd = self.qemu_img + ['create', '-f', backing_file_fmt,
>> +                               backing_file_name, str(backing_file_size)]
>> +        temp_log = StringIO.StringIO()
>> +        retcode = run_app(temp_log, cmd)
>> +        if retcode == 0:
>> +            temp_log.close()
>> +            return (backing_file_name, backing_file_fmt)
>> +        else:
>> +            multilog("Warning: The %s backing file was not created.\n\n"
>> +                     % backing_file_fmt, sys.stderr, self.log, 
>> self.parent_log)
>> +            self.log.write("Log for the failure:\n" + temp_log.getvalue() +
>> +                           '\n\n')
>> +            temp_log.close()
>> +            return (None, None)
>> +
>> +    def execute(self, input_commands=None, fuzz_config=None):
>> +        """ Execute a test.
>> +
>> +        The method creates backing and test images, runs test app and 
>> analyzes
>> +        its exit status. If the application was killed by a signal, the test
>> +        is marked as failed.
>> +        """
>> +        if input_commands is None:
>> +            commands = self.commands
>> +        else:
>> +            commands = input_commands
>> +
>> +        os.chdir(self.current_dir)
>> +        backing_file_name, backing_file_fmt = self._create_backing_file()
>> +        img_size = image_generator.create_image('test.img',
>> +                                                backing_file_name,
>> +                                                backing_file_fmt,
>> +                                                fuzz_config)
>> +        for item in commands:
>> +            shutil.copy('test.img', 'copy.img')
>> +            # 'off' and 'len' are multiple of the sector size
>> +            sector_size = 512
>> +            start = random.randrange(0, img_size + 1, sector_size)
>> +            end = random.randrange(start, img_size + 1, sector_size)
>> +
>> +            if item[0] == 'qemu-img':
>> +                current_cmd = list(self.qemu_img)
>> +            elif item[0] == 'qemu-io':
>> +                current_cmd = list(self.qemu_io)
>> +            else:
>> +                multilog("Warning: test command '%s' is not defined.\n" \
>> +                         % item[0], sys.stderr, self.log, self.parent_log)
>> +                continue
>> +            # Replace all placeholders with their real values
>> +            for v in item[1:]:
>> +                c = (v
>> +                     .replace('$test_img', 'copy.img')
>> +                     .replace('$off', str(start))
>> +                     .replace('$len', str(end - start)))
>> +                current_cmd.append(c)
>> +
>> +            # Log string with the test header
>> +            test_summary = "Seed: %s\nCommand: %s\nTest directory: %s\n" \
>> +                           "Backing file: %s\n" \
>> +                           % (self.seed, " ".join(current_cmd),
>> +                              self.current_dir, backing_file_name)
>> +
>> +            temp_log = StringIO.StringIO()
>> +            try:
>> +                retcode = run_app(temp_log, current_cmd)
>> +            except OSError, e:
>> +                multilog(test_summary + "Error: Start of '%s' failed. " \
>> +                         "Reason: %s\n\n" % (os.path.basename(
>> +                             current_cmd[0]), e[1]),
>> +                         sys.stderr, self.log, self.parent_log)
>> +                raise TestException
>> +
>> +            if retcode < 0:
>> +                self.log.write(temp_log.getvalue())
>> +                multilog(test_summary + "FAIL: Test terminated by signal " +
>> +                         "%s\n\n" % str_signal(-retcode), sys.stderr, 
>> self.log,
>> +                         self.parent_log)
>> +                self.failed = True
>> +            else:
>> +                if self.log_all:
>> +                    self.log.write(temp_log.getvalue())
>> +                    multilog(test_summary + "PASS: Application exited with" 
>> +
>> +                             " the code '%d'\n\n" % retcode, sys.stdout,
>> +                             self.log, self.parent_log)
>> +            temp_log.close()
>> +            os.remove('copy.img')
>> +
>> +    def finish(self):
>> +        """Restore the test environment after a test execution."""
>> +        self.log.close()
>> +        self.parent_log.close()
>> +        os.chdir(self.init_path)
>> +        if self.cleanup and not self.failed:
>> +            shutil.rmtree(self.current_dir)
>> +
>> +if __name__ == '__main__':
>> +
>> +    def usage():
>> +        print """
>> +        Usage: runner.py [OPTION...] TEST_DIR IMG_GENERATOR
>> +
>> +        Set up test environment in TEST_DIR and run a test in it. A module 
>> for
>> +        test image generation should be specified via IMG_GENERATOR.
>> +        Example:
>> +        runner.py -c '[["qemu-img", "info", "$test_img"]]' /tmp/test 
>> ../qcow2
>> +
>> +        Optional arguments:
>> +          -h, --help                    display this help and exit
>> +          -c, --command=JSON            run tests for all commands 
>> specified in
>> +                                        the JSON array
>> +          -s, --seed=STRING             seed for a test image generation,
>> +                                        by default will be generated 
>> randomly
>> +          --config=JSON                 take fuzzer configuration from the 
>> JSON
>> +                                        array
>> +          -k, --keep_passed             don't remove folders of passed tests
>> +          -v, --verbose                 log information about passed tests
>> +
>> +        JSON:
>> +
>> +        '--command' accepts a JSON array of commands. Each command presents
>> +        an application under test with all its paramaters as a list of 
>> strings,
>> +        e.g.
>> +          ["qemu-io", "$test_img", "-c", "write $off $len"]
>> +
>> +        Supported application aliases: 'qemu-img' and 'qemu-io'.
>> +        Supported argument aliases: $test_img for the fuzzed image, $off
>> +        for an offset, $len for length.
>> +
>> +        Values for $off and $len will be generated based on the virtual disk
>> +        size of the fuzzed image
>> +        Paths to 'qemu-img' and 'qemu-io' are retrevied from 'QEMU_IMG' and
>> +        'QEMU_IO' environment variables
>> +
>> +        '--config' accepts a JSON array of fields to be fuzzed, e.g.
>> +          '[["header"], ["header", "version"]]'
>> +        Each of the list elements can consist of a complex image element 
>> only
>> +        as ["header"] or ["feature_name_table"] or an exact field as
>> +        ["header", "version"]. In the first case random portion of the 
>> element
>> +        fields will be fuzzed, in the second one the specified field will be
>> +        fuzzed always.
>> +
>> +        If '--config' argument is specified, fields not listed in
>> +        the configuration array will not be fuzzed.
>> +        """
>> +
>> +    def run_test(test_id, seed, work_dir, run_log, cleanup, log_all,
>> +                 command, fuzz_config):
>> +        """Setup environment for one test and execute this test."""
>> +        try:
>> +            test = TestEnv(test_id, seed, work_dir, run_log, cleanup,
>> +                           log_all)
>> +        except TestException:
>> +            sys.exit(1)
>> +
>> +        # Python 2.4 doesn't support 'finally' and 'except' in the same 
>> 'try'
>> +        # block
>> +        try:
>> +            try:
>> +                test.execute(command, fuzz_config)
>> +            except TestException:
>> +                sys.exit(1)
>> +        finally:
>> +            test.finish()
>> +
>> +    try:
>> +        opts, args = getopt.gnu_getopt(sys.argv[1:], 'c:hs:kv',
>> +                                       ['command=', 'help', 'seed=', 
>> 'config=',
>> +                                        'keep_passed', 'verbose'])
>> +    except getopt.error, e:
>> +        print >>sys.stderr, \
>> +            "Error: %s\n\nTry 'runner.py --help' for more information" % e
>> +        sys.exit(1)
>> +
>> +    command = None
>> +    cleanup = True
>> +    log_all = False
>> +    seed = None
>> +    config = None
>> +    for opt, arg in opts:
>> +        if opt in ('-h', '--help'):
>> +            usage()
>> +            sys.exit()
>> +        elif opt in ('-c', '--command'):
>> +            try:
>> +                command = json.loads(arg)
>> +            except (TypeError, ValueError, NameError), e:
>> +                print >>sys.stderr, \
>> +                    "Error: JSON array of test commands cannot be 
>> loaded.\n" \
>> +                    "Reason: %s" % e
>> +                sys.exit(1)
>> +        elif opt in ('-k', '--keep_passed'):
>> +            cleanup = False
>> +        elif opt in ('-v', '--verbose'):
>> +            log_all = True
>> +        elif opt in ('-s', '--seed'):
>> +            seed = arg
>> +        elif opt == '--config':
>> +            try:
>> +                config = json.loads(arg)
>> +            except (TypeError, ValueError, NameError), e:
>> +                print >>sys.stderr, \
>> +                    "Error: JSON array with the fuzzer configuration 
>> cannot" \
>> +                    " be loaded\nReason: %s" % e
>> +                sys.exit(1)
>> +
>> +    if not len(args) == 2:
>> +        print >>sys.stderr, \
>> +            "Expected two parameters\nTry 'runner.py --help'" \
>> +            " for more information."
>> +        sys.exit(1)
>> +
>> +    work_dir = os.path.realpath(args[0])
>> +    # run_log is created in 'main', because multiple tests are expected to
>> +    # log in it
>> +    run_log = os.path.join(work_dir, 'run.log')
>> +
>> +    # Add the path to the image generator module to sys.path
>> +    sys.path.append(os.path.realpath(os.path.dirname(args[1])))
>> +    # Remove a script extension from image generator module if any
>> +    generator_name = os.path.splitext(os.path.basename(args[1]))[0]
>> +
>> +    try:
>> +        image_generator = __import__(generator_name)
>> +    except ImportError, e:
>> +        print >>sys.stderr, \
>> +            "Error: The image generator '%s' cannot be imported.\n" \
>> +            "Reason: %s" % (generator_name, e)
>> +        sys.exit(1)
>> +
>> +    # Enable core dumps
>> +    resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))
>> +    # If a seed is specified, only one test will be executed.
>> +    # Otherwise runner will terminate after a keyboard interruption
>> +    for test_id in count(1):
>> +        try:
>> +            run_test(str(test_id), seed, work_dir, run_log, cleanup,
>> +                     log_all, command, config)
>> +        except (KeyboardInterrupt, SystemExit):
>> +            sys.exit(1)
>> +
>> +        if seed is not None:
>> +            break
>> --
>> 1.9.3
>>