winafl-cmin: add --skip-dry-run to skip the dry run if it failed and …

…add support for AFL_NO_SINKHOLE to ease debugging

winafl-cmin.py

@@ -46,9 +46,12 @@ def _to_showmap_options(args, trace_name = '-'):
         '''Takes the argparse namespace, and convert it to the list of options used
         to invoke afl-showmap.exe'''
         r = [
-            'afl-showmap.exe', '-q', '-o', trace_name
+            'afl-showmap.exe', '-o', trace_name
         ]
 
+        if os.getenv('AFL_NO_SINKHOLE') is None:
+            r.append('-q')
+
         if args.time_limit > 0:
             r.extend(['-t', '%d' % args.time_limit])
         else:
@@ -267,6 +270,10 @@ def setup_argparse():
         '-w', '--workers', type = int, default = multiprocessing.cpu_count(),
         metavar = 'n', help = 'The number of worker processes (default: cpu count)'
     )
+    group.add_argument(
+        '--skip-dry-run', action = 'store_true', default = False,
+        help = 'Skip the dry-run step even if it failed'
+    )
     parser.add_argument(
         'target_cmdline', nargs = argparse.REMAINDER,
         help = 'target command line'
@@ -375,7 +382,9 @@ def main(argc, argv):
             '  Return codes matching? %r',
             results[0].returncode == results[1].returncode
         )
-        return 1
+
+        if not args.skip_dry_run:
+            return 1
 
     logging.info('[+] OK, %d tuples recorded.', len(results[0].tuples))