Merge pull request #640 from sosy-lab/improvements_windows_support

Avoid crash of benchexec on Windows due to SIGUSR1.

benchexec/benchexec.py

@@ -14,7 +14,6 @@
 import datetime
 import logging
 import os
-import signal
 import sys
 
 from benchexec import __version__
@@ -475,9 +474,7 @@ def signal_stop(signum, frame):
 
         # Handle termination-request signals that are available on the current platform
         for signal_name in ["SIGINT", "SIGQUIT", "SIGTERM", "SIGBREAK"]:
-            sig = getattr(signal, signal_name, None)
-            if sig:
-                signal.signal(sig, signal_stop)
+            util.try_set_signal_handler(signal_name, signal_stop)
 
         sys.exit(benchexec.start(argv or sys.argv))
     except BenchExecException as e:

benchexec/util.py

@@ -579,6 +579,16 @@ def kill_process(pid, sig=None):
             )
 
 
+def try_set_signal_handler(signal_name, handler):
+    """
+    Set signal handler like signal.signal(), but only if signal name exists on this
+    platform. Signal name must be a string starting with "SIG".
+    """
+    sig = getattr(_signal, signal_name, None)
+    if sig:
+        _signal.signal(sig, handler)
+
+
 def dummy_fn(*args, **kwargs):
     """Dummy function that accepts all parameters but does nothing."""
     pass
@@ -704,9 +714,9 @@ def _debug_current_process(sig, current_frame):
 
 def activate_debug_shell_on_signal():
     """Install a signal handler for USR1 that dumps stack traces
-    and gives an interactive debugging shell.
+    and gives an interactive debugging shell. Does nothing on Windows.
     """
-    _signal.signal(_signal.SIGUSR1, _debug_current_process)  # Register handler
+    try_set_signal_handler("SIGUSR1", _debug_current_process)
 
 
 def get_capability(filename):