add watchdog support

1 files changed, 103 insertions, 0 deletions

diff --git a/watchdog.c b/watchdog.c
new file mode 100644
index 0000000..98961d3
--- /dev/null
+++ b/watchdog.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1
+ * as published by the Free Software Foundation
+ *
+ * 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.
+ */
+
+#include <linux/watchdog.h>
+
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <unistd.h>
+
+#include <libubox/uloop.h>
+
+#include "procd.h"
+#include "watchdog.h"
+
+#define WDT_PATH	"/dev/watchdog"
+
+static struct uloop_timeout wdt_timeout;
+static int wdt_fd = -1;
+static int wdt_frequency = 5;
+
+static void watchdog_timeout_cb(struct uloop_timeout *t)
+{
+	DEBUG(2, "Ping\n");
+	if (write(wdt_fd, "X", 1) < 0)
+		perror("WDT failed to write\n");
+	uloop_timeout_set(t, wdt_frequency * 1000);
+}
+
+int watchdog_timeout(int timeout)
+{
+	if (wdt_fd < 0)
+		return 0;
+
+	if (timeout) {
+		DEBUG(2, "Set watchdog timeout: %ds\n", timeout);
+		ioctl(wdt_fd, WDIOC_SETTIMEOUT, &timeout);
+	}
+	ioctl(wdt_fd, WDIOC_GETTIMEOUT, &timeout);
+
+	return timeout;
+}
+
+int watchdog_frequency(int frequency)
+{
+	if (wdt_fd < 0)
+		return 0;
+
+	if (frequency) {
+		DEBUG(2, "Set watchdog frequency: %ds\n", frequency);
+		wdt_frequency = frequency;
+	}
+
+	return wdt_frequency;
+}
+
+char* watchdog_fd(void)
+{
+	static char fd_buf[3];
+
+	if (wdt_fd < 0)
+		return NULL;
+	snprintf(fd_buf, sizeof(fd_buf), "%d", wdt_fd);
+
+	return fd_buf;
+}
+
+void watchdog_init(void)
+{
+	char *env = getenv("WDTFD");
+
+	wdt_timeout.cb = watchdog_timeout_cb;
+	if (env) {
+		LOG("- watchdog -\n");
+		DEBUG(1, "Watchdog handover: fd=%s\n", env);
+		wdt_fd = atoi(env);
+		fcntl(wdt_fd, F_SETFD, fcntl(wdt_fd, F_GETFD) | FD_CLOEXEC);
+		unsetenv("WDTFD");
+	} else {
+		wdt_fd = open("/dev/watchdog", O_WRONLY);
+		if (getpid() != 1)
+			fcntl(wdt_fd, F_SETFD, fcntl(wdt_fd, F_GETFD) | FD_CLOEXEC);
+	}
+	if (wdt_fd < 0)
+		return;
+	watchdog_timeout(30);
+	watchdog_timeout_cb(&wdt_timeout);
+
+	DEBUG(2, "Opened watchdog with timeout %ds\n", watchdog_timeout(0));
+}