Fix #18: Add support for calling run/tasks on HOOK points

This patch implements support for calling run/task jobs on the built-in
`HOOK_*` points in Finit.  To map each HOOK point to a condition a new
classification was made, as shown in plugin.h and in the example below.

task <hook/mount/root> /sbin/attachubi.sh      # run in parallel with other tasks/services
run  <hook/net/up>     /sbin/dosomething.sh    # run in sequence with other commands

Please note, only rudimentary tested.

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

plugins/pidfile.c

@@ -114,7 +114,7 @@ static void pidfile_reconf(void *_null)
 		}
 
 		if (restart)
-			service_step_all(SVC_TYPE_SERVICE | SVC_TYPE_INETD);
+			service_step_all(SVC_TYPE_SERVICE | SVC_TYPE_RUNTASK | SVC_TYPE_INETD);
 
 	} while (restart);
 }

src/plugin.c

@@ -30,10 +30,12 @@
 #include <lite/queue.h>		/* BSD sys/queue.h API */
 
 #include "config.h"
+#include "cond.h"
 #include "finit.h"
-#include "private.h"
 #include "helpers.h"
 #include "plugin.h"
+#include "private.h"
+#include "service.h"
 
 #define is_io_plugin(p) ((p)->io.cb && (p)->io.fd > 0)
 #define SEARCH_PLUGIN(str)						\
@@ -163,6 +165,15 @@ plugin_t *plugin_find(char *name)
 }
 
 /* Private daemon API *******************************************************/
+#define CHOOSE(x, y) y
+static const char *hook_cond[] = HOOK_TYPES;
+#undef CHOOSE
+
+const char *plugin_hook_str(hook_point_t no)
+{
+	return hook_cond[no];
+}
+
 int plugin_exists(hook_point_t no)
 {
 	plugin_t *p, *tmp;
@@ -178,14 +189,34 @@ int plugin_exists(hook_point_t no)
 /* Some hooks are called with a fixed argument, like HOOK_SVC_LOST */
 void plugin_run_hook(hook_point_t no, void *arg)
 {
+	static int last = -1;
 	plugin_t *p, *tmp;
 
+	/*
+	 * End recursion: any plugin hook => start service => SVC start
+	 * hook => start service ... err ... wait a second
+	 */
+	if (HOOK_SVC_START == last) {
+		_d("End plugin recursion in our lifetime!");
+		return;
+	}
+
 	PLUGIN_ITERATOR(p, tmp) {
 		if (p->hook[no].cb) {
 			_d("Calling %s hook n:o %d (arg: %p) ...", basename(p->name), no, arg);
 			p->hook[no].cb(arg ? arg : p->hook[no].arg);
 		}
 	}
+
+	/* Guard against infinite recursion */
+	if (HOOK_SVC_START == no)
+		last = no;
+
+	cond_set(hook_cond[no]);
+	service_step_all(SVC_TYPE_RUNTASK);
+
+	if (HOOK_SVC_START == no)
+		last = -1;
 }
 
 /* Regular hooks are called with the registered plugin's argument */

src/plugin.h

@@ -51,28 +51,34 @@
 #define PLUGIN_ITERATOR(x, tmp) TAILQ_FOREACH_SAFE(x, &plugins, link, tmp)
 
 /*
- * Predefined hook points for easier plugin debugging 
+ * Predefined hook points and corresponding conditions in Finit,
+ * for use by plugins and scripts.  Recommended to use the task
+ * or run stanzas:  task <hook/mount/error> /bin/rescue.sh
  */
-typedef enum {
-	/* Bootstrap hooks */
-	HOOK_BANNER = 0,
-	HOOK_ROOTFS_UP,
-	HOOK_MOUNT_ERROR,
-	HOOK_BASEFS_UP,
-	HOOK_NETWORK_UP,
-	HOOK_SVC_UP,
-	HOOK_SYSTEM_UP,
+#define HOOK_TYPES {						\
+	/* Bootstrap hooks, runlevel [S] */			\
+	CHOOSE(HOOK_BANNER = 0,      "hook/sys/banner"),	\
+	CHOOSE(HOOK_ROOTFS_UP,       "hook/mount/root"),	\
+	CHOOSE(HOOK_MOUNT_ERROR,     "hook/mount/error"),	\
+	CHOOSE(HOOK_BASEFS_UP,       "hook/mount/all"),		\
+	CHOOSE(HOOK_NETWORK_UP,      "hook/net/up"),		\
+	CHOOSE(HOOK_SVC_UP,          "hook/svc/up"),		\
+	CHOOSE(HOOK_SYSTEM_UP,       "hook/sys/up"),		\
+								\
+	/* Runtime hooks, runlevel [S1-9] */			\
+	CHOOSE(HOOK_SVC_RECONF,      "hook/svc/reconf"),	\
+	CHOOSE(HOOK_SVC_LOST,        "hook/svc/lost"),		\
+	CHOOSE(HOOK_SVC_START,       "hook/svc/start"),		\
+	CHOOSE(HOOK_RUNLEVEL_CHANGE, "hook/sys/runlevel"),	\
+								\
+	/* Shutdown hooks, runlevel [06] */			\
+	CHOOSE(HOOK_SHUTDOWN,        "hook/sys/shutdown"),	\
+	CHOOSE(HOOK_MAX_NUM,         "nop")			\
+}
 
-	/* Runtime hooks */
-	HOOK_SVC_RECONF,
-	HOOK_SVC_LOST,
-	HOOK_SVC_START,
-	HOOK_RUNLEVEL_CHANGE,
-
-	/* Shutdown hooks */
-	HOOK_SHUTDOWN,
-	HOOK_MAX_NUM
-} hook_point_t;
+#define CHOOSE(x, y) x
+typedef enum HOOK_TYPES hook_point_t;
+#undef CHOOSE
 
 /**
  * plugin_t - Finit &plugin_t object

src/private.h

@@ -40,6 +40,7 @@ int       client           (int argc, char *argv[]);
 
 void      service_monitor  (pid_t lost);
 
+const char *plugin_hook_str(hook_point_t no);
 int       plugin_exists    (hook_point_t no);
 void      plugin_run_hook  (hook_point_t no, void *arg);
 void      plugin_run_hooks (hook_point_t no);