Greatly simplify svc hook for external plugins

This commit removes a lot of unnecessary overhead for handling external
service plugins.  Instead of traversing the plugin array every time a
service callback should run we set the plugin callback in the svc_t when
the plugin is registered.

Also, make sure to check for norespawn/SIGSTOP in svc_reload() as well.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

plugin.c

@@ -32,7 +32,6 @@
 #include "private.h"
 #include "helpers.h"
 #include "plugin.h"
-#include "svc.h"
 
 #define is_io_plugin(p) ((p)->io.cb && (p)->io.fd >= 0)
 
@@ -69,11 +68,13 @@ int plugin_register(plugin_t *plugin)
 	}
 
 	if (plugin->svc.cb) {
-		svc_t *svc = svc_find_by_name(plugin->name);
+		svc_t *svc = svc_find(plugin->name);
 
 		if (svc) {
-			plugin->svc.id = svc_id(svc);
 			inuse++;
+			svc->cb           = plugin->svc.cb;
+			svc->dynamic      = plugin->svc.dynamic;
+			svc->dynamic_stop = plugin->svc.dynamic_stop;
 		}
 	}
 
@@ -91,6 +92,15 @@ int plugin_unregister(plugin_t *plugin)
 {
 	LIST_REMOVE(plugin, link);
 
+	if (plugin->svc.cb) {
+		svc_t *svc = svc_find(plugin->name);
+
+		if (svc) {
+			svc->cb      = NULL;
+			svc->dynamic = 0;
+		}
+	}
+
 	/* XXX: Unfinished, add cleanup code here! */
 
 	return 0;
@@ -109,21 +119,6 @@ void plugin_run_hooks(hook_point_t no)
 	}
 }
 
-/* Run registered plugin service callback for the given svc ID */
-svc_cmd_t plugin_svc_enabled(svc_t *svc, int event, void *arg)
-{
-	plugin_t *p;
-
-	/* Find matching plugin, pick first matching fd */
-	PLUGIN_ITERATOR(p) {
-		if (p->svc.id == svc_id(svc))
-			return p->svc.cb(svc, event, arg);
-	}
-
-	/* Unknown service, default to start (since it's in finit.conf) */
-	return SVC_START;
-}
-
 /* Generic libev I/O callback, looks up correct plugin and calls its callback */
 static void generic_io_cb(int fd, int events)
 {

plugin.h

@@ -83,11 +83,8 @@ typedef struct plugin {
 
 	/* Service callback to be called once per lap of runloop. */
 	struct {
-		/* Private */
-		int         id;       /* Service ID# to match this service plugin against, set on installation. */
-
-		/* Public */
-		int         dynamic;  /* Reload (SIGHUP) on dynamic event?  Set by plugin. */
+		int dynamic;      /* Callback wants external events as well. */
+		int dynamic_stop; /* Callback allows dynamic events to stop. */
 		svc_cmd_t (*cb)(svc_t *svc, int event, void *event_arg);
 	} svc;
 

private.h

@@ -28,13 +28,12 @@
 #include "svc.h"
 #include "plugin.h"
 
-void      svc_start_all      (void);
-void      svc_monitor        (void);
+void      svc_start_all    (void);
+void      svc_monitor      (void);
 
-void      plugin_run_hooks   (hook_point_t no);
-svc_cmd_t plugin_svc_enabled (svc_t *svc, int event, void *arg);
-int       plugin_load_all    (char *path);
-void      plugin_monitor     (void);
+void      plugin_run_hooks (hook_point_t no);
+int       plugin_load_all  (char *path);
+void      plugin_monitor   (void);
 
 #endif /* FINIT_PRIVATE_H_ */
 

svc.c

@@ -66,7 +66,6 @@ svc_t *svc_new(void)
 	if (svc_counter < MAX_NUM_SVC) {
 		svc = &services[svc_counter++];
 		memset(svc, 0, sizeof(*svc));
-		svc->id = svc_counter; /* Array pos + 1 to avoid zero ID */
 	} else {
 		errno = ENOMEM;
 		return NULL;
@@ -76,29 +75,13 @@ svc_t *svc_new(void)
 }
 
 /**
- * svc_find_by_id - Find a service object by its logical ID#
- * @id: Logical ID#
- *
- * Returns:
- * A pointer to an &svc_t object, or %NULL if not found.
- */
-svc_t *svc_find_by_id(int id)
-{
-	__connect_shm();
-	if (id < 1 || id > svc_counter)
-		return NULL;
-
-	return &services[id - 1];
-}
-
-/**
- * svc_find_by_name - Find a service object by its full path name
+ * svc_find - Find a service object by its full path name
  * @name: Full path name, e.g., /sbin/syslogd
  *
  * Returns:
  * A pointer to an &svc_t object, or %NULL if not found.
  */
-svc_t *svc_find_by_name(char *name)
+svc_t *svc_find(char *name)
 {
 	int i;
 
@@ -226,7 +209,12 @@ svc_cmd_t svc_enabled(svc_t *svc, int event, void *arg)
 		return SVC_STOP;
 	}
 
-	return plugin_svc_enabled(svc, event, arg);
+	/* Is there a service plugin registered? */
+	if (svc->cb)
+		return svc->cb(svc, event, arg);
+
+	/* No service plugin, default to start, since listed in finit.conf */
+	return SVC_START;
 }
 
 static int is_norespawn(void)
@@ -335,7 +323,7 @@ int svc_start(svc_t *svc)
 
 int svc_start_by_name(char *name)
 {
-	svc_t *svc = svc_find_by_name(name);
+	svc_t *svc = svc_find(name);
 
 	if (svc && svc_enabled(svc, 0, NULL))
 		return svc_start(svc);
@@ -369,6 +357,10 @@ int svc_stop(svc_t *svc)
 
 int svc_reload(svc_t *svc)
 {
+	/* Ignore if finit is SIGSTOP'ed */
+	if (is_norespawn())
+		return 0;
+
 	if (!svc) {
 		_e("Failed, no svc pointer.");
 		return 1;

svc.h

@@ -48,17 +48,22 @@ typedef enum {
  * of issuing an initctl call. E.g.
  *   initctl <stop|start|restart> service */
 typedef struct svc {
-	/* Private */
-	int            id;	/* Service ID#, set by svc_new() */
 	pid_t	       pid;
+	int	       reload;
 	char	       cmd[MAX_ARG_LEN];
 	char	       args[MAX_NUM_SVC_ARGS][MAX_ARG_LEN];
 	char	       desc[MAX_STR_LEN];
 	char           username[MAX_USER_LEN];
 
-	/* Public */
-	int	       reload;   /* For external plugins. */
-	int            private;  /* For callbacks to use freely, possibly to store "states", set by plugin. */
+	/* For external plugins. If @cb is set a plugin is loaded.
+	 * @dynamic:      Set by plugins that want dynamic events.
+	 * @dynamic_stop: Set by plugins that allow dyn. events to stop it as well.
+	 * @private:      Can be used freely by plugin, e.g., to store "states".
+	 */
+	int            dynamic;
+	int            dynamic_stop;
+	int            private;
+	svc_cmd_t    (*cb)(struct svc *svc, int event, void *event_arg);
 } svc_t;
 
 typedef struct svc_map svc_map_t;
@@ -78,19 +83,8 @@ static inline svc_t *finit_svc_connect(void)
 	return (svc_t *)ptr;
 }
 
-static inline int svc_id(svc_t *svc)
-{
-	if (!svc) {
-		errno = EINVAL;
-		return -1;
-	}
-
-	return svc->id;
-}
-
 svc_t    *svc_new           (void);
-svc_t    *svc_find_by_id    (int id);
-svc_t    *svc_find_by_name  (char *name);
+svc_t    *svc_find          (char *name);
 svc_t    *svc_iterator      (int restart);
 
 int       svc_register      (char *line, char *username);