Refactor the crashesat interestingness test to use argparse, logging and pathlib

src/funfuzz/util/crashesat.py

@@ -4,62 +4,69 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
-"""Lithium's "crashesat" interestingness test to assess whether a binary crashes at a desired location.
+"""Lithium's "crashesat" interestingness test to assess whether a binary crashes with a possibly-desired signature on
+the stack.
 
-Not merged into Lithium, unsure if this still works for now. Still relies on grabCrashLog.
+Not merged into Lithium as it still relies on grabCrashLog.
 """
 
-from __future__ import absolute_import, print_function  # isort:skip
+from __future__ import absolute_import
 
-from optparse import OptionParser  # pylint: disable=deprecated-module
-import os
+import argparse
+import logging
+import sys
 
 import lithium.interestingness.timed_run as timed_run
 from lithium.interestingness.utils import file_contains
 
 from . import subprocesses as sps
 
-
-def parse_options(arguments):  # pylint: disable=missing-docstring,missing-return-doc,missing-return-type-doc
-    parser = OptionParser()
-    parser.disable_interspersed_args()
-    parser.add_option("-r", "--regex", action="store_true", dest="useRegex",
-                      default=False,
-                      help="Allow search for regular expressions instead of strings.")
-    parser.add_option("-s", "--sig", action="store", dest="sig",
-                      default="",
-                      help='Match this crash signature. Defaults to "%default".')
-    parser.add_option("-t", "--timeout", type="int", action="store", dest="condTimeout",
-                      default=120,
-                      help='Optionally set the timeout. Defaults to "%default" seconds.')
-
-    options, args = parser.parse_args(arguments)
-
-    return options.useRegex, options.sig, options.condTimeout, args
-
-
-def interesting(cli_args, temp_prefix):  # pylint: disable=missing-docstring,missing-return-doc,missing-return-type-doc
-    (regex_enabled, crash_sig, timeout, args) = parse_options(cli_args)
-
-    # Examine stack for crash signature, this is needed if crash_sig is specified.
-    runinfo = timed_run.timed_run(args, timeout, temp_prefix)
+if sys.version_info.major == 2:
+    from pathlib2 import Path
+else:
+    from pathlib import Path  # pylint: disable=import-error
+
+
+def interesting(cli_args, temp_prefix):
+    """Interesting if the binary crashes with a possibly-desired signature on the stack.
+
+    Args:
+        cli_args (list): List of input arguments.
+        temp_prefix (str): Temporary directory prefix, e.g. tmp1/1 or tmp4/1
+
+    Returns:
+        bool: True if the intended signature shows up on the stack, False otherwise.
+    """
+    parser = argparse.ArgumentParser(prog="crashesat",
+                                     usage="python -m lithium %(prog)s [options] binary [flags] testcase.ext")
+    parser.add_argument("-r", "--regex", action="store_true", default=False,
+                        help="Allow search for regular expressions instead of strings.")
+    parser.add_argument("-s", "--sig", default="", type=str,
+                        help="Match this crash signature. Defaults to '%default'.")
+    parser.add_argument("-t", "--timeout", default=120, type=int,
+                        help="Optionally set the timeout. Defaults to '%default' seconds.")
+    parser.add_argument("cmd_with_flags", nargs=argparse.REMAINDER)
+    args = parser.parse_args(cli_args)
+
+    log = logging.getLogger(__name__)
+
+    # Examine stack for crash signature, this is needed if args.sig is specified.
+    runinfo = timed_run.timed_run(args.cmd_with_flags, args.timeout, temp_prefix)
     if runinfo.sta == timed_run.CRASHED:
-        sps.grabCrashLog(args[0], runinfo.pid, temp_prefix, True)
+        sps.grabCrashLog(args.cmd_with_flags[0], runinfo.pid, temp_prefix, True)
 
+    crash_log = Path(temp_prefix + "-crash.txt")
     time_str = " (%.3f seconds)" % runinfo.elapsedtime
 
-    crash_log = temp_prefix + "-crash.txt"
-
     if runinfo.sta == timed_run.CRASHED:
-        if os.path.exists(crash_log):
+        if crash_log.resolve().is_file():  # pylint: disable=no-member
             # When using this script, remember to escape characters, e.g. "\(" instead of "(" !
-            found, _found_sig = file_contains(crash_log, crash_sig, regex_enabled)
-            if found:
-                print("Exit status: %s%s" % (runinfo.msg, time_str))
+            if file_contains(str(crash_log), args.sig, args.regex)[0]:
+                log.info("Exit status: %s%s", runinfo.msg, time_str)
                 return True
-            print("[Uninteresting] It crashed somewhere else!" + time_str)
+            log.info("[Uninteresting] It crashed somewhere else!%s", time_str)
             return False
-        print("[Uninteresting] It appeared to crash, but no crash log was found?" + time_str)
+        log.info("[Uninteresting] It appeared to crash, but no crash log was found?%s", time_str)
         return False
-    print("[Uninteresting] It didn't crash." + time_str)
+    log.info("[Uninteresting] It didn't crash.%s", time_str)
     return False