[NaCl SDK] Add keyboard interrupt handlers for python scripts

native_client_sdk/src/tools/create_nmf.py

Index: native_client_sdk/src/tools/create_nmf.py
diff --git a/native_client_sdk/src/tools/create_nmf.py b/native_client_sdk/src/tools/create_nmf.py
index 5c9d270d9956450ec146b2fd50ca4c0c65ebe692..6ca83abbf574c8e0d5e8014d695706965213b31b 100755
--- a/native_client_sdk/src/tools/create_nmf.py
+++ b/native_client_sdk/src/tools/create_nmf.py
@@ -635,6 +635,12 @@ def main(argv):
   if len(args) < 1:
     raise Error('No nexe files specified.  See --help for more info')
 
+  for filename in args:
+    if not os.path.exists(filename):
+      raise Error('Input file not found: %s' % filename)
+    if not os.path.isfile(filename):
+      raise Error('Input is not a file: %s' % filename)
+
   canonicalized = ParseExtraFiles(options.extra_files, sys.stderr)
   if canonicalized is None:
     parser.error('Bad --extra-files (-x) argument syntax')
@@ -684,4 +690,7 @@ if __name__ == '__main__':
   except Error, e:
     sys.stderr.write('%s: %s\n' % (os.path.basename(__file__), e))
     rtn = 1
+  except KeyboardInterrupt:
+    sys.stderr.write('%s: interrupted\n' % os.path.basename(__file__))
+    rtn = 1
   sys.exit(rtn)