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Diffstat (limited to 'release/src/router/busybox/networking/udhcp/signalpipe.c')
-rw-r--r--release/src/router/busybox/networking/udhcp/signalpipe.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/release/src/router/busybox/networking/udhcp/signalpipe.c b/release/src/router/busybox/networking/udhcp/signalpipe.c
new file mode 100644
index 00000000..a025bd8b
--- /dev/null
+++ b/release/src/router/busybox/networking/udhcp/signalpipe.c
@@ -0,0 +1,82 @@
+/* vi: set sw=4 ts=4: */
+/* signalpipe.c
+ *
+ * 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 "common.h"
+
+
+static struct fd_pair signal_pipe;
+
+static void signal_handler(int sig)
+{
+ unsigned char ch = sig; /* use char, avoid dealing with partial writes */
+ if (write(signal_pipe.wr, &ch, 1) != 1)
+ bb_perror_msg("cannot send signal");
+}
+
+
+/* Call this before doing anything else. Sets up the socket pair
+ * and installs the signal handler */
+void FAST_FUNC udhcp_sp_setup(void)
+{
+ /* was socketpair, but it needs AF_UNIX in kernel */
+ xpiped_pair(signal_pipe);
+ close_on_exec_on(signal_pipe.rd);
+ close_on_exec_on(signal_pipe.wr);
+ ndelay_on(signal_pipe.wr);
+ bb_signals(0
+ + (1 << SIGUSR1)
+ + (1 << SIGUSR2)
+ + (1 << SIGTERM)
+ , 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 FAST_FUNC udhcp_sp_fd_set(fd_set *rfds, int extra_fd)
+{
+ FD_ZERO(rfds);
+ FD_SET(signal_pipe.rd, rfds);
+ if (extra_fd >= 0) {
+ close_on_exec_on(extra_fd);
+ FD_SET(extra_fd, rfds);
+ }
+ return signal_pipe.rd > extra_fd ? signal_pipe.rd : 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 FAST_FUNC udhcp_sp_read(const fd_set *rfds)
+{
+ unsigned char sig;
+
+ if (!FD_ISSET(signal_pipe.rd, rfds))
+ return 0;
+
+ if (safe_read(signal_pipe.rd, &sig, 1) != 1)
+ return -1;
+
+ return sig;
+}