Bug 935677 - Exit status reported by wait is incorrect

mozprocess/mozprocess/processhandler.py

@@ -521,8 +521,14 @@ def _wait(self):
 
                 if not self._ignore_children:
                     try:
-                        # os.waitpid returns a (pid, status) tuple
-                        return os.waitpid(self.pid, 0)[1]
+                        # os.waitpid return value:
+                        # > [...] a tuple containing its pid and exit status
+                        # > indication: a 16-bit number, whose low byte is the
+                        # > signal number that killed the process, and whose
+                        # > high byte is the exit status (if the signal number
+                        # > is zero)
+                        # - http://docs.python.org/2/library/os.html#os.wait
+                        return os.waitpid(self.pid, 0)[1] >> 8
                     except OSError, e:
                         if getattr(e, "errno", None) != 10:
                             # Error 10 is "no child process", which could indicate normal
@@ -736,6 +742,8 @@ def wait(self, timeout=None):
         If timeout is not None, will return after timeout seconds.
         This timeout only causes the wait function to return and
         does not kill the process.
+
+        Returns the process's exit code.
         """
         if self.outThread:
             # Thread.join() blocks the main thread until outThread is finished