1 files changed, 122 insertions, 0 deletions
diff --git a/hbeat.c b/hbeat.c
new file mode 100644
index 0000000..e0255a3
--- /dev/null
+++ b/hbeat.c
@@ -0,0 +1,122 @@
+/*
+ * hbeat.c --
+ *
+ *	Simple heartbeating.
+ *
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <time.h>
+
+#include "btime.h"
+#include "hbeat.h"
+
+
+struct hbeat_s {
+	char *host;
+	int max_timeout;
+	enum {HOST_ALIVE, HOST_QUIET, HOST_TIMEOUT, HOST_REBOOT} rhost_state;
+	unsigned int last_rhost_btime;
+	time_t start_quiet_time;
+};
+
+
+/*
+ * hbeat_init --
+ *
+ *	Init a heartbeat to host, with max_timeout as supplied.
+ *
+ *	Returns: 
+ *	A hbeat handle, or NULL on error;
+ */
+
+hbeat_t 
+hbeat_init(const char *host, int max_timeout)
+{
+	struct hbeat_s *hbeatp;
+
+	hbeatp = malloc(sizeof *hbeatp);
+	if (!hbeatp) {
+		return NULL;
+	}
+
+	hbeatp->host = strdup(host);
+	hbeatp->max_timeout = max_timeout;
+	hbeatp->rhost_state = HOST_ALIVE;
+	hbeatp->last_rhost_btime = 0;
+	hbeatp->start_quiet_time = 0;
+
+	return hbeatp;
+}
+
+
+/*
+ * hbeat_free --
+ *
+ *	Free a hbeat handle.
+ */
+
+void 
+hbeat_free(hbeat_t hbh)
+{
+	struct hbeat_s *hbeatp = hbh;
+	
+	free(hbeatp->host);
+	free(hbeatp);
+}
+	
+
+/*
+ * hbeat --
+ *
+ *	Attempt to contact host in the hbeat handle, run the hbeat
+ *	"state machine" to decide if we the host is still "alive."
+ *
+ *	Returns:
+ *		1 if host has been active or responded withing max_timeout secs.
+ *		0 if host is dead, no response for > max_timeout secs.
+ */
+
+unsigned int
+hbeat(hbeat_t hbh)
+{
+	struct hbeat_s *hbeatp = hbh;
+	unsigned int hbeat;
+	time_t current_time;
+
+	/* User disabled heart beating */
+	if (!hbeatp->max_timeout) {
+		return 1;
+	}
+
+	hbeat = btime(hbeatp->host);
+	current_time = time(NULL);
+
+	if (!hbeat && (hbeatp->rhost_state == HOST_QUIET)) {
+		if (current_time - hbeatp->start_quiet_time 
+		     > hbeatp->max_timeout) {
+			hbeatp->rhost_state = HOST_TIMEOUT;
+			return 0;
+		}
+	} else {
+		hbeatp->rhost_state = HOST_QUIET;
+		hbeatp->start_quiet_time = time(NULL);
+	}
+
+	if (hbeat) {
+		if (hbeatp->last_rhost_btime == 0) {
+			hbeatp->last_rhost_btime = hbeat;
+			hbeatp->rhost_state = HOST_ALIVE;
+			hbeatp->start_quiet_time = 0;
+		}
+			
+		if (abs(hbeat - hbeatp->last_rhost_btime) > 5) {
+			hbeatp->rhost_state = HOST_REBOOT;
+			return 0;
+		} 
+	}
+
+	return 1;	
+}