Add dhcpcd-3 re-write

1 files changed, 91 insertions, 0 deletions

diff --git a/signals.c b/signals.c
new file mode 100644
index 00000000..b565b8d2
--- /dev/null
+++ b/signals.c
@@ -0,0 +1,91 @@
+/* 
+ * Shameless taken from udhcp as I think it's a good idea.
+ * Signal pipe infrastructure. A reliable way of delivering signals.
+ *
+ * Russ Dill <Russ.Dill@asu.edu> December 2003
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "logger.h"
+
+static int signal_pipe[2];
+
+static void signal_handler (int sig)
+{
+  if (send (signal_pipe[1], &sig, sizeof (sig), MSG_DONTWAIT) < 0)
+    logger (LOG_ERR, "Could not send signal: %s", strerror (errno));
+}
+
+
+/* Call this before doing anything else. Sets up the socket pair
+ * and installs the signal handler */
+void signal_setup(void)
+{
+  int i;
+  int flags;
+
+  socketpair (AF_UNIX, SOCK_STREAM, 0, signal_pipe);
+
+  /* Stop any scripts from inheriting us */
+  for (i = 0; i < 2; i++)
+    if ((flags = fcntl (signal_pipe[i], F_GETFD, 0)) < 0 ||
+	fcntl (signal_pipe[i], F_SETFD, flags | FD_CLOEXEC) < 0)
+      logger (LOG_ERR ,"fcntl: %s", strerror (errno));
+  
+  signal (SIGHUP, signal_handler);
+  signal (SIGALRM, signal_handler);
+  signal (SIGTERM, signal_handler);
+  signal (SIGINT, signal_handler);
+}
+
+
+/* Quick little function to setup the rfds. Will return the
+ * max_fd for use with select. Limited in that you can only pass
+ * one extra fd */
+int signal_fd_set (fd_set *rfds, int extra_fd)
+{
+  FD_ZERO (rfds);
+  FD_SET (signal_pipe[0], rfds);
+  if (extra_fd >= 0)
+    FD_SET (extra_fd, rfds);
+  return signal_pipe[0] > extra_fd ? signal_pipe[0] : extra_fd;
+}
+
+
+/* Read a signal from the signal pipe. Returns 0 if there is
+ * no signal, -1 on error (and sets errno appropriately), and
+ * your signal on success */
+int signal_read (fd_set *rfds)
+{
+  int sig;
+
+  if (!FD_ISSET (signal_pipe[0], rfds))
+    return 0;
+
+  if (read (signal_pipe[0], &sig, sizeof (sig)) < 0)
+    return -1;
+
+  return sig;
+}
+