Initial Contribution

1 files changed, 137 insertions, 0 deletions

diff --git a/signals.c b/signals.c
new file mode 100644
index 0000000..fb986d7
--- /dev/null
+++ b/signals.c
@@ -0,0 +1,137 @@
+/* 
+ * dhcpcd - DHCP client daemon
+ * Copyright 2006-2008 Roy Marples <roy@marples.name>
+ * All rights reserved
+
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <errno.h>
+#include <poll.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "common.h"
+#include "signals.h"
+
+static int signal_pipe[2];
+
+static const int handle_sigs[] = {
+	SIGHUP,
+	SIGALRM,
+	SIGTERM,
+	SIGINT
+};
+
+static void
+signal_handler(int sig)
+{
+	int serrno = errno;
+
+	write(signal_pipe[1], &sig, sizeof(sig));
+	/* Restore errno */
+	errno = serrno;
+}
+
+int
+signal_fd(void)
+{
+	return (signal_pipe[0]);
+}
+
+/* Check if we have a signal or not */
+int
+signal_exists(int fd)
+{
+	if (fd_hasdata(fd) == 1)
+		return 0;
+	return -1;
+}
+
+/* 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(int fd)
+{
+	int sig = -1;
+	char buf[16];
+	size_t bytes;
+
+	if (fd_hasdata(fd) == 1) {
+		memset(buf, 0, sizeof(buf));
+		bytes = read(signal_pipe[0], buf, sizeof(buf));
+		if (bytes >= sizeof(sig))
+			memcpy(&sig, buf, sizeof(sig));
+	}
+	return sig;
+}
+
+/* Call this before doing anything else. Sets up the socket pair
+ * and installs the signal handler */
+int
+signal_init(void)
+{
+	if (pipe(signal_pipe) == -1)
+		return -1;
+	/* Don't block on read */
+	if (set_nonblock(signal_pipe[0]) == -1)
+		return -1;
+	/* Stop any scripts from inheriting us */
+	if (set_cloexec(signal_pipe[0]) == -1)
+		return -1;
+	if (set_cloexec(signal_pipe[1]) == -1)
+		return -1;
+	return 0;
+}
+
+static int
+signal_handle(void (*func)(int))
+{
+	unsigned int i;
+	struct sigaction sa;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = func;
+	sigemptyset(&sa.sa_mask);
+
+	for (i = 0; i < sizeof(handle_sigs) / sizeof(handle_sigs[0]); i++)
+		if (sigaction(handle_sigs[i], &sa, NULL) == -1)
+			return -1;
+	return 0;
+}
+
+int
+signal_setup(void)
+{
+	return signal_handle(signal_handler);
+}
+
+int
+signal_reset(void)
+{
+	return signal_handle(SIG_DFL);
+}