Remove support for service callback plugins

This patch removes the now heavily outdated (and non-working) support
for callback plugins.  I.e. plugins that attach themselves to services
listed in /etc/finit.conf and can be queried to determine if a service
should be started or stopped.

The Finit3 support for adding/removing services at runtime with plain
text *.conf files in /etc/finit.d and `initctl reload`, this old, and
rather cumbersome service callback feature, is not longer supported.

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

doc/plugins.md

@@ -1,10 +1,11 @@
-Hooks, Callbacks & Plugins
-==========================
+Hooks & Plugins
+===============
 
-Finit provides only the bare necessities for starting and supervising
-processes, with an emphasis on *bare* — for your convenience it does
-however come with support for hooks, service callbacks and plugins that
-can used to extend finit with.
+Finit can be extended to add general functionality in the form of I/O
+monitors, built-in inetd services, or hook plugins.
+
+The following sections detail existing plugins and hook points.  For
+more information, see the plugins listed below.
 
 
 Plugins
@@ -124,20 +125,6 @@ they are called I/O plugins and are called from the finit main loop when
 more help and ideas.
 
 
-Callbacks
----------
-
-Callback plugins are called by finit right before a process is started,
-or restarted if it exits.  The callback runs as a separate process and
-receives a pointer to the `svc_t` of the service, with all command line
-parameters free to modify as needed.
-
-All the callback needs to do is respond with one of: `SVC_STOP (0)`
-tells Finit to *not* start the service, `SVC_START (1)` to start the
-service, or `SVC_RELOAD (2)` to have finit signal the process with
-`SIGHUP`.
-
-
 <!--
   -- Local Variables:
   -- mode: markdown

plugin.c

@@ -109,20 +109,6 @@ int plugin_unregister(plugin_t *plugin)
 #ifndef ENABLE_STATIC
 	TAILQ_REMOVE(&plugins, plugin, link);
 
-	if (plugin->svc.cb) {
-		svc_t *svc;
-
-		/* Unregister plugin callback for all matching services */
-		for (svc = svc_iterator(1); svc; svc = svc_iterator(0)) {
-			if (strcmp(svc->cmd, plugin->name))
-				continue;
-
-			svc->cb           = NULL;
-			svc->dynamic      = 0;
-			svc->dynamic_stop = 0;
-		}
-	}
-
 	_d("%s exiting ...", plugin->name);
 	free(plugin->name);
 #else

plugin.h

@@ -100,13 +100,6 @@ typedef struct plugin {
 	 * NOTE: Must match cmd for services or inetd plugins! */
 	char *name;
 
-	/* Service callback to be called once per lap of runloop. */
-	struct {
-		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;
-
 	/* List of hook callbacks. */
 	struct {
 		void  *arg;      /* Optional argument to callback func. */

service.c

@@ -608,13 +608,6 @@ recreate:
 		while ((cmd = strtok(NULL, " ")))
 			strlcpy(svc->args[i++], cmd, sizeof(svc->args[0]));
 		svc->args[i][0] = 0;
-
-		plugin = plugin_find(svc->cmd);
-		if (plugin && plugin->svc.cb) {
-			svc->cb           = plugin->svc.cb;
-			svc->dynamic      = plugin->svc.dynamic;
-			svc->dynamic_stop = plugin->svc.dynamic_stop;
-		}
 	}
 
 	svc->runlevels = conf_parse_runlevels(runlevels);

svc.h

@@ -33,11 +33,7 @@
 #include "inetd.h"
 #include "helpers.h"
 
-typedef enum {
-	SVC_STOP = 0,		/* Disabled */
-	SVC_START,		/* Enabled */
-	SVC_RELOAD		/* Enabled, needs restart */
-} svc_cmd_t;
+typedef int svc_cmd_t;
 
 typedef enum {
 	SVC_TYPE_FREE       = 0,	/* Free to allocate */
@@ -113,16 +109,6 @@ typedef struct svc {
 	char	       cmd[MAX_ARG_LEN];
 	char	       args[MAX_NUM_SVC_ARGS][MAX_ARG_LEN];
 	char	       desc[MAX_STR_LEN];
-
-	/* 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;