add respawn handling

Signed-off-by: John Crispin <blogic@openwrt.org>

3 files changed, 57 insertions, 10 deletions

diff --git a/instance.c b/instance.c
index d61bb33..e263b84 100644
--- a/instance.c
+++ b/instance.c
@@ -32,6 +32,7 @@ enum {
 	INSTANCE_ATTR_NETDEV,
 	INSTANCE_ATTR_FILE,
 	INSTANCE_ATTR_TRIGGER,
+	INSTANCE_ATTR_RESPAWN,
 	INSTANCE_ATTR_NICE,
 	__INSTANCE_ATTR_MAX
 };
@@ -43,6 +44,7 @@ static const struct blobmsg_policy instance_attr[__INSTANCE_ATTR_MAX] = {
 	[INSTANCE_ATTR_NETDEV] = { "netdev", BLOBMSG_TYPE_ARRAY },
 	[INSTANCE_ATTR_FILE] = { "file", BLOBMSG_TYPE_ARRAY },
 	[INSTANCE_ATTR_TRIGGER] = { "triggers", BLOBMSG_TYPE_ARRAY },
+	[INSTANCE_ATTR_RESPAWN] = { "respawn", BLOBMSG_TYPE_ARRAY },
 	[INSTANCE_ATTR_NICE] = { "nice", BLOBMSG_TYPE_INT32 },
 };
 
@@ -102,6 +104,8 @@ instance_start(struct service_instance *in)
 		return;
 
 	in->restart = false;
+	in->halt = !in->respawn;
+
 	if (!in->valid)
 		return;
 
@@ -117,6 +121,7 @@ instance_start(struct service_instance *in)
 
 	DEBUG(1, "Started instance %s::%s\n", in->srv->name, in->name);
 	in->proc.pid = pid;
+	clock_gettime(CLOCK_MONOTONIC, &in->start);
 	uloop_process_add(&in->proc);
 }
 
@@ -126,29 +131,58 @@ instance_timeout(struct uloop_timeout *t)
 	struct service_instance *in;
 
 	in = container_of(t, struct service_instance, timeout);
-	kill(in->proc.pid, SIGKILL);
-	uloop_process_delete(&in->proc);
-	in->proc.cb(&in->proc, -1);
+
+	if (!in->halt && (in->restart || in->respawn))
+		instance_start(in);
 }
 
 static void
 instance_exit(struct uloop_process *p, int ret)
 {
 	struct service_instance *in;
+	struct timespec tp;
+	long runtime;
 
 	in = container_of(p, struct service_instance, proc);
-	DEBUG(1, "Instance %s::%s exit with error code %d\n", in->srv->name, in->name, ret);
+
+	clock_gettime(CLOCK_MONOTONIC, &tp);
+	runtime = tp.tv_sec - in->start.tv_sec;
+
+	DEBUG(1, "Instance %s::%s exit with error code %d after %ld seconds\n", in->srv->name, in->name, ret, runtime);
 	uloop_timeout_cancel(&in->timeout);
-	if (in->restart)
+	if (in->halt) {
+		/* no action */
+	} else if (in->restart) {
 		instance_start(in);
+	} else if (in->respawn) {
+		if (runtime < RESPAWN_ERROR)
+			in->respawn_count++;
+		else
+			in->respawn_count = 0;
+		if (in->respawn_count > 5)
+			DEBUG(1, "Instance %s::%s s in a crash loop %d crashes, %ld seconds since last crash\n",
+								in->srv->name, in->name, in->respawn_count, runtime);
+		uloop_timeout_set(&in->timeout, 5000);
+	}
 }
 
 void
-instance_stop(struct service_instance *in, bool restart)
+instance_stop(struct service_instance *in)
 {
 	if (!in->proc.pending)
 		return;
+	in->halt = true;
+	in->restart = in->respawn = false;
+	kill(in->proc.pid, SIGTERM);
+}
 
+static void
+instance_restart(struct service_instance *in)
+{
+	if (!in->proc.pending)
+		return;
+	in->halt = false;
+	in->restart = true;
 	kill(in->proc.pid, SIGTERM);
 }
 
@@ -348,9 +382,9 @@ instance_update(struct service_instance *in, struct service_instance *in_new)
 			instance_config_move(in, in_new);
 		instance_start(in);
 	} else {
-		in->restart = true;
-		instance_stop(in, true);
+		instance_restart(in);
 		instance_config_move(in, in_new);
+		/* restart happens in the child callback handler */
 	}
 	return true;
 }
@@ -375,6 +409,8 @@ instance_init(struct service_instance *in, struct service *s, struct blob_attr *
 	in->config = config;
 	in->timeout.cb = instance_timeout;
 	in->proc.cb = instance_exit;
+	in->respawn = true;
+	in->respawn_count = 0;
 
 	blobmsg_list_init(&in->netdev, struct instance_netdev, node, instance_netdev_cmp);
 	blobmsg_list_init(&in->file, struct instance_file, node, instance_file_cmp);
diff --git a/instance.h b/instance.h
index ceae834..1c8c0a0 100644
--- a/instance.h
+++ b/instance.h
@@ -19,6 +19,8 @@
 #include <libubox/uloop.h>
 #include "utils.h"
 
+#define RESPAWN_ERROR	(5 * 60)
+
 struct service_instance {
 	struct vlist_node node;
 	struct service *srv;
@@ -26,7 +28,16 @@ struct service_instance {
 
 	int8_t nice;
 	bool valid;
+
+	bool halt;
 	bool restart;
+	bool respawn;
+	int respawn_count;
+	struct timespec start;
+
+	int respawn_timeout;
+	int respawn_threshold;
+	int respawn_retry;
 
 	struct blob_attr *config;
 	struct uloop_process proc;
@@ -41,7 +52,7 @@ struct service_instance {
 };
 
 void instance_start(struct service_instance *in);
-void instance_stop(struct service_instance *in, bool restart);
+void instance_stop(struct service_instance *in);
 bool instance_update(struct service_instance *in, struct service_instance *in_new);
 void instance_init(struct service_instance *in, struct service *s, struct blob_attr *config);
 void instance_free(struct service_instance *in);
diff --git a/service.c b/service.c
index 561c76c..c80402c 100644
--- a/service.c
+++ b/service.c
@@ -55,7 +55,7 @@ service_instance_update(struct vlist_tree *tree, struct vlist_node *node_new,
 		instance_free(in_n);
 	} else if (in_o) {
 		DEBUG(1, "Free instance %s::%s\n", in_o->srv->name, in_o->name);
-		instance_stop(in_o, false);
+		instance_stop(in_o);
 		instance_free(in_o);
 	} else if (in_n) {
 		DEBUG(1, "Create instance %s::%s\n", in_n->srv->name, in_n->name);