[V4,2/5] runner: Tool for fuzz tests execution

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 <maria.k@catit.be>
---
 tests/image-fuzzer/runner/runner.py | 360 ++++++++++++++++++++++++++++++++++++
 1 file changed, 360 insertions(+)
 create mode 100755 tests/image-fuzzer/runner/runner.py

On Mon, 07/21 14:18, 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 <maria.k@catit.be>

Looks good. Only two minor comments below but neither is a stopper.

> ---
>  tests/image-fuzzer/runner/runner.py | 360 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 360 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..3e9e65d
> --- /dev/null
> +++ b/tests/image-fuzzer/runner/runner.py
> @@ -0,0 +1,360 @@
> +#!/usr/bin/env python
> +
> +# Tool for running fuzz tests
> +#
> +# Copyright (C) 2014 Maria Kustova <maria.k@catit.be>
> +#
> +# 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, os, signal
> +import subprocess
> +import random
> +from itertools import count
> +from shutil import rmtree
> +import getopt
> +try:
> +    import json
> +except ImportError:
> +    try:
> +        import simplejson as json
> +    except ImportError:
> +        print "Warning: Module for JSON processing is not found.\n" + \
> +            "'--config' and '--command' options are not supported."
> +import resource
> +resource.setrlimit(resource.RLIMIT_CORE, (-1, -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
> +
> +
> +class TestException(Exception):
> +    """Exception for errors risen by TestEnv objects"""
> +    pass
> +
> +
> +class TestEnv(object):
> +    """ Trivial 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.
> +    Summary log will contain short descriptions and statuses of tests in
> +    a run.
> +    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(' ')
> +        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 _test_app(self, q_args):
> +        """ Start application under test with specified arguments and return
> +        an exit code or a kill signal depending on the result of execution.
> +        """
> +        devnull = open('/dev/null', 'r+')
> +        return subprocess.call(q_args, stdin=devnull, stdout=self.log,
> +                               stderr=self.log)
> +
> +    def _create_backing_file(self):
> +        """Create a backing file in the current directory and return
> +        its name and file format
> +
> +        Format of a backing file is randomly chosen from all formats supported
> +        by 'qemu-img create'
> +        """
> +        # All formats qemu-img can create images of.
> +        backing_file_fmt = random.choice(['raw', 'vmdk', 'vdi', 'cow', 'qcow2',
> +                                          'file', 'qed', 'vpc'])
> +        backing_file_name = 'backing_img.' + backing_file_fmt
> +        # Size of the backing file varies from 1 to 10 MB
> +        backing_file_size = random.randint(1, 10)*(1 << 20)

Missing whitespaces around '*'.

> +        cmd = self.qemu_img + ['create', '-f', backing_file_fmt,
> +                               backing_file_name, str(backing_file_size)]
> +        devnull = open('/dev/null', 'r+')
> +        retcode = subprocess.call(cmd, stdin=devnull, stdout=self.log,
> +                                  stderr=self.log)
> +        if retcode == 0:

We can assert retcode == 0.

> +            return [backing_file_name, backing_file_fmt]
> +        else:
> +            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_image',
> +                                                backing_file_name,
> +                                                backing_file_fmt,
> +                                                fuzz_config)
> +        for item in commands:
> +            start = random.randint(0, img_size)
> +            end = random.randint(start, img_size)
> +            current_cmd = list(self.__dict__[item[0].replace('-', '_')])
> +            # Replace all placeholders with their real values
> +            for v in item[1:]:
> +                c = v.replace('$test_img', 'test_image').\
> +                    replace('$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)
> +            try:
> +                retcode = self._test_app(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:
> +                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:
> +                    multilog(test_summary + "PASS: Application exited with" + \
> +                             " the code '%d'\n\n" % retcode, sys.stdout,
> +                             self.log, self.parent_log)
> +
> +    def finish(self):
> +        """ Restore environment after a test execution. Remove folders of
> +        passed tests
> +        """
> +        self.log.close()
> +        self.parent_log.close()
> +        os.chdir(self.init_path)
> +        if self.cleanup and not self.failed:
> +            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)
> +            # Silent exit on user break
> +            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 "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 "Error: JSON array of test commands cannot be loaded"\
> +                    "\nReason: %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 "Error: JSON array with the fuzzer configuration " \
> +                    "cannot be loaded\nReason: %s" % e
> +                sys.exit(1)
> +
> +    if not len(args) == 2:
> +        print "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.dirname(os.path.realpath(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 "Error: The image generator '%s' cannot be imported.\n" \
> +            "Reason: %s" % (generator_name, e)
> +        sys.exit(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
>

On Mon, Jul 21, 2014 at 02:18:09PM +0400, Maria Kustova wrote:
> +    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_image',
> +                                                backing_file_name,
> +                                                backing_file_fmt,
> +                                                fuzz_config)
> +        for item in commands:
> +            start = random.randint(0, img_size)
> +            end = random.randint(start, img_size)
> +            current_cmd = list(self.__dict__[item[0].replace('-', '_')])

This special case for self.qemu_img and self.qemu_io is not obvious to
me when reading the code.  It would be clearer to use the same
$qemu_img/$qemu_io substitution mechanism as for $test_img/$off/$len
below.

On Fri, Aug 1, 2014 at 9:46 AM, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> On Mon, Jul 21, 2014 at 02:18:09PM +0400, Maria Kustova wrote:
>> +    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_image',
>> +                                                backing_file_name,
>> +                                                backing_file_fmt,
>> +                                                fuzz_config)
>> +        for item in commands:
>> +            start = random.randint(0, img_size)
>> +            end = random.randint(start, img_size)
>> +            current_cmd = list(self.__dict__[item[0].replace('-', '_')])
>
> This special case for self.qemu_img and self.qemu_io is not obvious to
> me when reading the code.  It would be clearer to use the same
> $qemu_img/$qemu_io substitution mechanism as for $test_img/$off/$len
> below.
Separate processing of test programs is due to the impossibility to
laconically replace a string with an unpacked list of strings.
But I agree that using of __dict__ is not safe and have to be redesigned.

BR, M.