add -t option to ssh, to second sudo

[sliver-openvswitch.git] / lib / signals.c

diff --git a/lib/signals.c b/lib/signals.c
index 37f0637..b712f7e 100644 (file)
--- a/lib/signals.c
+++ b/lib/signals.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2011 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2011, 2012 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@
 #include <errno.h>
 #include <limits.h>
 #include <signal.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include "poll-loop.h"
 #include "socket-util.h"
@@ -40,6 +41,7 @@ VLOG_DEFINE_THIS_MODULE(signals);
 #endif
 
 struct signal {
+    struct sigaction saved_sa;
     int signr;
 };
 
@@ -62,8 +64,8 @@ signal_init(void)
     if (!inited) {
         inited = true;
         xpipe(fds);
-        set_nonblocking(fds[0]);
-        set_nonblocking(fds[1]);
+        xset_nonblocking(fds[0]);
+        xset_nonblocking(fds[1]);
     }
 }
 
@@ -78,20 +80,31 @@ signal_register(int signr)
 
     signal_init();
 
+    s = xmalloc(sizeof *s);
+    s->signr = signr;
+
     /* Set up signal handler. */
     assert(signr >= 1 && signr < N_SIGNALS);
     memset(&sa, 0, sizeof sa);
     sa.sa_handler = signal_handler;
     sigemptyset(&sa.sa_mask);
     sa.sa_flags = SA_RESTART;
-    xsigaction(signr, &sa, NULL);
+    xsigaction(signr, &sa, &s->saved_sa);
 
-    /* Return structure. */
-    s = xmalloc(sizeof *s);
-    s->signr = signr;
     return s;
 }
 
+/* Unregisters the handler for 's', restores the signal handler that was in
+ * effect before signal_register() was called, and frees 's'. */
+void
+signal_unregister(struct signal *s)
+{
+    if (s) {
+        xsigaction(s->signr, &s->saved_sa, NULL);
+        free(s);
+    }
+}
+
 /* Returns true if signal 's' has been received since the last call to this
  * function with argument 's'. */
 bool