tests/image-fuzzer/runner.py

   1 #!/usr/bin/env python
   2
   3 # Tool for running fuzz tests
   4 #
   5 # Copyright (C) 2014 Maria Kustova <maria.k@catit.be>
   6 #
   7 # This program is free software: you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation, either version 2 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 #
  20
  21 import sys
  22 import os
  23 import signal
  24 import subprocess
  25 import random
  26 import shutil
  27 from itertools import count
  28 import time
  29 import getopt
  30 import StringIO
  31 import resource
  32
  33 try:
  34     import json
  35 except ImportError:
  36     try:
  37         import simplejson as json
  38     except ImportError:
  39         print >>sys.stderr, \
  40             "Warning: Module for JSON processing is not found.\n" \
  41             "'--config' and '--command' options are not supported."
  42
  43 # Backing file sizes in MB
  44 MAX_BACKING_FILE_SIZE = 10
  45 MIN_BACKING_FILE_SIZE = 1
  46
  47
  48 def multilog(msg, *output):
  49     """ Write an object to all of specified file descriptors."""
  50     for fd in output:
  51         fd.write(msg)
  52         fd.flush()
  53
  54
  55 def str_signal(sig):
  56     """ Convert a numeric value of a system signal to the string one
  57     defined by the current operational system.
  58     """
  59     for k, v in signal.__dict__.items():
  60         if v == sig:
  61             return k
  62
  63
  64 def run_app(fd, q_args):
  65     """Start an application with specified arguments and return its exit code
  66     or kill signal depending on the result of execution.
  67     """
  68
  69     class Alarm(Exception):
  70         """Exception for signal.alarm events."""
  71         pass
  72
  73     def handler(*args):
  74         """Notify that an alarm event occurred."""
  75         raise Alarm
  76
  77     signal.signal(signal.SIGALRM, handler)
  78     signal.alarm(600)
  79     term_signal = signal.SIGKILL
  80     devnull = open('/dev/null', 'r+')
  81     process = subprocess.Popen(q_args, stdin=devnull,
  82                                stdout=subprocess.PIPE,
  83                                stderr=subprocess.PIPE)
  84     try:
  85         out, err = process.communicate()
  86         signal.alarm(0)
  87         fd.write(out)
  88         fd.write(err)
  89         fd.flush()
  90         return process.returncode
  91
  92     except Alarm:
  93         os.kill(process.pid, term_signal)
  94         fd.write('The command was terminated by timeout.\n')
  95         fd.flush()
  96         return -term_signal
  97
  98
  99 class TestException(Exception):
 100     """Exception for errors risen by TestEnv objects."""
 101     pass
 102
 103
 104 class TestEnv(object):
 105
 106     """Test object.
 107
 108     The class sets up test environment, generates backing and test images
 109     and executes application under tests with specified arguments and a test
 110     image provided.
 111
 112     All logs are collected.
 113
 114     The summary log will contain short descriptions and statuses of tests in
 115     a run.
 116
 117     The test log will include application (e.g. 'qemu-img') logs besides info
 118     sent to the summary log.
 119     """
 120
 121     def __init__(self, test_id, seed, work_dir, run_log,
 122                  cleanup=True, log_all=False):
 123         """Set test environment in a specified work directory.
 124
 125         Path to qemu-img and qemu-io will be retrieved from 'QEMU_IMG' and
 126         'QEMU_IO' environment variables.
 127         """
 128         if seed is not None:
 129             self.seed = seed
 130         else:
 131             self.seed = str(random.randint(0, sys.maxint))
 132         random.seed(self.seed)
 133
 134         self.init_path = os.getcwd()
 135         self.work_dir = work_dir
 136         self.current_dir = os.path.join(work_dir, 'test-' + test_id)
 137         self.qemu_img = \
 138             os.environ.get('QEMU_IMG', 'qemu-img').strip().split(' ')
 139         self.qemu_io = os.environ.get('QEMU_IO', 'qemu-io').strip().split(' ')
 140         self.commands = [['qemu-img', 'check', '-f', 'qcow2', '$test_img'],
 141                          ['qemu-img', 'info', '-f', 'qcow2', '$test_img'],
 142                          ['qemu-io', '$test_img', '-c', 'read $off $len'],
 143                          ['qemu-io', '$test_img', '-c', 'write $off $len'],
 144                          ['qemu-io', '$test_img', '-c',
 145                           'aio_read $off $len'],
 146                          ['qemu-io', '$test_img', '-c',
 147                           'aio_write $off $len'],
 148                          ['qemu-io', '$test_img', '-c', 'flush'],
 149                          ['qemu-io', '$test_img', '-c',
 150                           'discard $off $len'],
 151                          ['qemu-io', '$test_img', '-c',
 152                           'truncate $off']]
 153         for fmt in ['raw', 'vmdk', 'vdi', 'qcow2', 'file', 'qed', 'vpc']:
 154             self.commands.append(
 155                 ['qemu-img', 'convert', '-f', 'qcow2', '-O', fmt,
 156                  '$test_img', 'converted_image.' + fmt])
 157
 158         try:
 159             os.makedirs(self.current_dir)
 160         except OSError as e:
 161             print >>sys.stderr, \
 162                 "Error: The working directory '%s' cannot be used. Reason: %s"\
 163                 % (self.work_dir, e[1])
 164             raise TestException
 165         self.log = open(os.path.join(self.current_dir, "test.log"), "w")
 166         self.parent_log = open(run_log, "a")
 167         self.failed = False
 168         self.cleanup = cleanup
 169         self.log_all = log_all
 170
 171     def _create_backing_file(self):
 172         """Create a backing file in the current directory.
 173
 174         Return a tuple of a backing file name and format.
 175
 176         Format of a backing file is randomly chosen from all formats supported
 177         by 'qemu-img create'.
 178         """
 179         # All formats supported by the 'qemu-img create' command.
 180         backing_file_fmt = random.choice(['raw', 'vmdk', 'vdi', 'qcow2',
 181                                           'file', 'qed', 'vpc'])
 182         backing_file_name = 'backing_img.' + backing_file_fmt
 183         backing_file_size = random.randint(MIN_BACKING_FILE_SIZE,
 184                                            MAX_BACKING_FILE_SIZE) * (1 << 20)
 185         cmd = self.qemu_img + ['create', '-f', backing_file_fmt,
 186                                backing_file_name, str(backing_file_size)]
 187         temp_log = StringIO.StringIO()
 188         retcode = run_app(temp_log, cmd)
 189         if retcode == 0:
 190             temp_log.close()
 191             return (backing_file_name, backing_file_fmt)
 192         else:
 193             multilog("Warning: The %s backing file was not created.\n\n"
 194                      % backing_file_fmt, sys.stderr, self.log, self.parent_log)
 195             self.log.write("Log for the failure:\n" + temp_log.getvalue() +
 196                            '\n\n')
 197             temp_log.close()
 198             return (None, None)
 199
 200     def execute(self, input_commands=None, fuzz_config=None):
 201         """ Execute a test.
 202
 203         The method creates backing and test images, runs test app and analyzes
 204         its exit status. If the application was killed by a signal, the test
 205         is marked as failed.
 206         """
 207         if input_commands is None:
 208             commands = self.commands
 209         else:
 210             commands = input_commands
 211
 212         os.chdir(self.current_dir)
 213         backing_file_name, backing_file_fmt = self._create_backing_file()
 214         img_size = image_generator.create_image(
 215             'test.img', backing_file_name, backing_file_fmt, fuzz_config)
 216         for item in commands:
 217             shutil.copy('test.img', 'copy.img')
 218             # 'off' and 'len' are multiple of the sector size
 219             sector_size = 512
 220             start = random.randrange(0, img_size + 1, sector_size)
 221             end = random.randrange(start, img_size + 1, sector_size)
 222
 223             if item[0] == 'qemu-img':
 224                 current_cmd = list(self.qemu_img)
 225             elif item[0] == 'qemu-io':
 226                 current_cmd = list(self.qemu_io)
 227             else:
 228                 multilog("Warning: test command '%s' is not defined.\n"
 229                          % item[0], sys.stderr, self.log, self.parent_log)
 230                 continue
 231             # Replace all placeholders with their real values
 232             for v in item[1:]:
 233                 c = (v
 234                      .replace('$test_img', 'copy.img')
 235                      .replace('$off', str(start))
 236                      .replace('$len', str(end - start)))
 237                 current_cmd.append(c)
 238
 239             # Log string with the test header
 240             test_summary = "Seed: %s\nCommand: %s\nTest directory: %s\n" \
 241                            "Backing file: %s\n" \
 242                            % (self.seed, " ".join(current_cmd),
 243                               self.current_dir, backing_file_name)
 244             temp_log = StringIO.StringIO()
 245             try:
 246                 retcode = run_app(temp_log, current_cmd)
 247             except OSError as e:
 248                 multilog("%sError: Start of '%s' failed. Reason: %s\n\n"
 249                          % (test_summary, os.path.basename(current_cmd[0]),
 250                             e[1]),
 251                          sys.stderr, self.log, self.parent_log)
 252                 raise TestException
 253
 254             if retcode < 0:
 255                 self.log.write(temp_log.getvalue())
 256                 multilog("%sFAIL: Test terminated by signal %s\n\n"
 257                          % (test_summary, str_signal(-retcode)),
 258                          sys.stderr, self.log, self.parent_log)
 259                 self.failed = True
 260             else:
 261                 if self.log_all:
 262                     self.log.write(temp_log.getvalue())
 263                     multilog("%sPASS: Application exited with the code " \
 264                              "'%d'\n\n" % (test_summary, retcode),
 265                              sys.stdout, self.log, self.parent_log)
 266             temp_log.close()
 267             os.remove('copy.img')
 268
 269     def finish(self):
 270         """Restore the test environment after a test execution."""
 271         self.log.close()
 272         self.parent_log.close()
 273         os.chdir(self.init_path)
 274         if self.cleanup and not self.failed:
 275             shutil.rmtree(self.current_dir)
 276
 277 if __name__ == '__main__':
 278
 279     def usage():
 280         print """
 281         Usage: runner.py [OPTION...] TEST_DIR IMG_GENERATOR
 282
 283         Set up test environment in TEST_DIR and run a test in it. A module for
 284         test image generation should be specified via IMG_GENERATOR.
 285
 286         Example:
 287           runner.py -c '[["qemu-img", "info", "$test_img"]]' /tmp/test qcow2
 288
 289         Optional arguments:
 290           -h, --help                    display this help and exit
 291           -d, --duration=NUMBER         finish tests after NUMBER of seconds
 292           -c, --command=JSON            run tests for all commands specified in
 293                                         the JSON array
 294           -s, --seed=STRING             seed for a test image generation,
 295                                         by default will be generated randomly
 296           --config=JSON                 take fuzzer configuration from the JSON
 297                                         array
 298           -k, --keep_passed             don't remove folders of passed tests
 299           -v, --verbose                 log information about passed tests
 300
 301         JSON:
 302
 303         '--command' accepts a JSON array of commands. Each command presents
 304         an application under test with all its parameters as a list of strings,
 305         e.g. ["qemu-io", "$test_img", "-c", "write $off $len"].
 306
 307         Supported application aliases: 'qemu-img' and 'qemu-io'.
 308
 309         Supported argument aliases: $test_img for the fuzzed image, $off
 310         for an offset, $len for length.
 311
 312         Values for $off and $len will be generated based on the virtual disk
 313         size of the fuzzed image.
 314
 315         Paths to 'qemu-img' and 'qemu-io' are retrevied from 'QEMU_IMG' and
 316         'QEMU_IO' environment variables.
 317
 318         '--config' accepts a JSON array of fields to be fuzzed, e.g.
 319         '[["header"], ["header", "version"]]'.
 320
 321         Each of the list elements can consist of a complex image element only
 322         as ["header"] or ["feature_name_table"] or an exact field as
 323         ["header", "version"]. In the first case random portion of the element
 324         fields will be fuzzed, in the second one the specified field will be
 325         fuzzed always.
 326
 327         If '--config' argument is specified, fields not listed in
 328         the configuration array will not be fuzzed.
 329         """
 330
 331     def run_test(test_id, seed, work_dir, run_log, cleanup, log_all,
 332                  command, fuzz_config):
 333         """Setup environment for one test and execute this test."""
 334         try:
 335             test = TestEnv(test_id, seed, work_dir, run_log, cleanup,
 336                            log_all)
 337         except TestException:
 338             sys.exit(1)
 339
 340         # Python 2.4 doesn't support 'finally' and 'except' in the same 'try'
 341         # block
 342         try:
 343             try:
 344                 test.execute(command, fuzz_config)
 345             except TestException:
 346                 sys.exit(1)
 347         finally:
 348             test.finish()
 349
 350     def should_continue(duration, start_time):
 351         """Return True if a new test can be started and False otherwise."""
 352         current_time = int(time.time())
 353         return (duration is None) or (current_time - start_time < duration)
 354
 355     try:
 356         opts, args = getopt.gnu_getopt(sys.argv[1:], 'c:hs:kvd:',
 357                                        ['command=', 'help', 'seed=', 'config=',
 358                                         'keep_passed', 'verbose', 'duration='])
 359     except getopt.error as e:
 360         print >>sys.stderr, \
 361             "Error: %s\n\nTry 'runner.py --help' for more information" % e
 362         sys.exit(1)
 363
 364     command = None
 365     cleanup = True
 366     log_all = False
 367     seed = None
 368     config = None
 369     duration = None
 370     for opt, arg in opts:
 371         if opt in ('-h', '--help'):
 372             usage()
 373             sys.exit()
 374         elif opt in ('-c', '--command'):
 375             try:
 376                 command = json.loads(arg)
 377             except (TypeError, ValueError, NameError) as e:
 378                 print >>sys.stderr, \
 379                     "Error: JSON array of test commands cannot be loaded.\n" \
 380                     "Reason: %s" % e
 381                 sys.exit(1)
 382         elif opt in ('-k', '--keep_passed'):
 383             cleanup = False
 384         elif opt in ('-v', '--verbose'):
 385             log_all = True
 386         elif opt in ('-s', '--seed'):
 387             seed = arg
 388         elif opt in ('-d', '--duration'):
 389             duration = int(arg)
 390         elif opt == '--config':
 391             try:
 392                 config = json.loads(arg)
 393             except (TypeError, ValueError, NameError) as e:
 394                 print >>sys.stderr, \
 395                     "Error: JSON array with the fuzzer configuration cannot" \
 396                     " be loaded\nReason: %s" % e
 397                 sys.exit(1)
 398
 399     if not len(args) == 2:
 400         print >>sys.stderr, \
 401             "Expected two parameters\nTry 'runner.py --help'" \
 402             " for more information."
 403         sys.exit(1)
 404
 405     work_dir = os.path.realpath(args[0])
 406     # run_log is created in 'main', because multiple tests are expected to
 407     # log in it
 408     run_log = os.path.join(work_dir, 'run.log')
 409
 410     # Add the path to the image generator module to sys.path
 411     sys.path.append(os.path.realpath(os.path.dirname(args[1])))
 412     # Remove a script extension from image generator module if any
 413     generator_name = os.path.splitext(os.path.basename(args[1]))[0]
 414
 415     try:
 416         image_generator = __import__(generator_name)
 417     except ImportError as e:
 418         print >>sys.stderr, \
 419             "Error: The image generator '%s' cannot be imported.\n" \
 420             "Reason: %s" % (generator_name, e)
 421         sys.exit(1)
 422
 423     # Enable core dumps
 424     resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))
 425     # If a seed is specified, only one test will be executed.
 426     # Otherwise runner will terminate after a keyboard interruption
 427     start_time = int(time.time())
 428     test_id = count(1)
 429     while should_continue(duration, start_time):
 430         try:
 431             run_test(str(test_id.next()), seed, work_dir, run_log, cleanup,
 432                      log_all, command, config)
 433         except (KeyboardInterrupt, SystemExit):
 434             sys.exit(1)
 435
 436         if seed is not None:
 437             break