oeqa/core/decorator: Add support for OETimeout decorator

The OETimeout provides support for specify certain timeout
in seconds for a test case, if the timeout is reach the SIGALRM
is sent and an exception is raised to notify the timeout.

[YOCTO #10235]

(From OE-Core rev: 1bf66a370361912e9950d7ff45e382c93622a169)

Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com>
Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/core/decorator/oetimeout.py

@@ -0,0 +1,25 @@
+# Copyright (C) 2016 Intel Corporation
+# Released under the MIT license (see COPYING.MIT)
+
+import signal
+from . import OETestDecorator, registerDecorator
+from oeqa.core.exception import OEQATimeoutError
+
+@registerDecorator
+class OETimeout(OETestDecorator):
+    attrs = ('oetimeout',)
+
+    def setUpDecorator(self):
+        timeout = self.oetimeout
+        def _timeoutHandler(signum, frame):
+            raise OEQATimeoutError("Timed out after %s "
+                    "seconds of execution" % timeout)
+
+        self.logger.debug("Setting up a %d second(s) timeout" % self.oetimeout)
+        self.alarmSignal = signal.signal(signal.SIGALRM, _timeoutHandler)
+        signal.alarm(self.oetimeout)
+
+    def tearDownDecorator(self):
+        signal.alarm(0)
+        signal.signal(signal.SIGALRM, self.alarmSignal)
+        self.logger.debug("Removed SIGALRM handler")