Follow-up to c9fe9afa, proper fix for HOOK_BASFFS_UP mess

Instead of the revert in c9fe9afa, we restore HOOK_BASFFS_UP to its
proper place at the end of fs_mount_all().  For this to not cause any
regressions we add a new hook, HOOK_SVC_PLUGIN, and update all plugins
that call service_register() to run at the new hook.

This will cause regressions for external 3rd party plugins that rely on
HOOK_BASEFS_UP to be called at its previous postion.  Nevertheless, this
is the proper fix to the problem.

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

doc/plugins.md

@@ -168,6 +168,12 @@ hook points:
 * `HOOK_BASEFS_UP`, `hook/mount/all`: All of `/etc/fstab` is mounted,
   swap is available and default init signals are setup
 
+* `HOOK_SVC_PLUGIN`, `hook/svc/plugin`: Called in `conf_init()` right
+  before loading `/etc/finit.conf`.  For plugins to register any early
+  run/task/services, please do NOT use any earlier hook point.  That
+  will cause uninitialized rlimits that lead to unpredictable results
+  when Finit later tries to start the run/task/service.
+
 * `HOOK_NETWORK_UP`, `hook/net/up`: System bootstrap, runlevel S, has
   completed and networking is up (`lo` is up and the `network` script
   has run)

plugins/dbus.c

@@ -163,11 +163,8 @@ static void setup(void *arg)
 }
 
 static plugin_t plugin = {
-	.name = __FILE__,
+	.name                  = __FILE__,
-	.hook[HOOK_BASEFS_UP] = {
+	.hook[HOOK_SVC_PLUGIN] = { .cb  = setup },
-		.cb  = setup
-	},
-	.depends = { "bootmisc", },
 };
 
 PLUGIN_INIT(plugin_init)

plugins/hotplug.c

@@ -91,11 +91,8 @@ static void setup(void *arg)
 }
 
 static plugin_t plugin = {
-	.name = __FILE__,
+	.name                  = __FILE__,
-	.hook[HOOK_BASEFS_UP] = {
+	.hook[HOOK_SVC_PLUGIN] = { .cb  = setup },
-		.cb  = setup
-	},
-	.depends = { "bootmisc", "modprobe" },
 };
 
 PLUGIN_INIT(plugin_init)

plugins/modules-load.c

@@ -212,10 +212,8 @@ static void load(void *arg)
 }
 
 static plugin_t plugin = {
-	.name = __FILE__,
+	.name                  = __FILE__,
-	.hook[HOOK_BASEFS_UP] = {
+	.hook[HOOK_SVC_PLUGIN] = { .cb  = load },
-		.cb  = load
-	},
 };
 
 PLUGIN_INIT(plugin_init)

src/conf.c

@@ -1209,6 +1209,9 @@ int conf_init(uev_ctx_t *ctx)
 	/* Initialize global rlimits, e.g. for built-in services */
 	memcpy(global_rlimit, initial_rlimit, sizeof(global_rlimit));
 
+	dbg("Allow plugins to register early runlevel 1 run/task/services ...");
+	plugin_run_hooks(HOOK_SVC_PLUGIN);
+
 	/* Read global rlimits and global cgroup setup from /etc/finit.conf */
 	parse_conf(finit_conf, 0);
 

src/finit.c

@@ -476,6 +476,9 @@ static void fs_mount_all(void)
 
 	dbg("Finalize, ensure common file systems are available ...");
 	fs_finalize();
+
+	dbg("Base FS up, calling hooks ...");
+	plugin_run_hooks(HOOK_BASEFS_UP);
 }
 
 /*
@@ -789,7 +792,11 @@ int main(int argc, char *argv[])
 	 */
 	fs_mount_all();
 
-	/* Bootstrap conditions, needed for hooks */
+	/*
+	 * Base FS up, enable standard SysV init signals and
+	 * Bootstrap conditions, needed for hooks
+	 */
+	sig_setup(&loop);
 	cond_init();
 
 	/*
@@ -821,12 +828,6 @@ int main(int argc, char *argv[])
 	if (whichp(FINIT_LIBPATH_ "/keventd"))
 		service_register(SVC_TYPE_SERVICE, "[123456789] cgroup.init " FINIT_LIBPATH_ "/keventd -- Finit kernel event daemon", global_rlimit, NULL);
 
-	/* Base FS up, enable standard SysV init signals */
-	sig_setup(&loop);
-
-	dbg("Base FS up, calling hooks ...");
-	plugin_run_hooks(HOOK_BASEFS_UP);
-
 	/*
 	 * Set up inotify watcher for /etc/finit.conf, /etc/finit.d, and
 	 * their deps, to figure out how to bootstrap the system.

src/plugin.h

@@ -72,6 +72,7 @@
 	CHOOSE(HOOK_MOUNT_ERROR,     "hook/mount/error"),	\
 	CHOOSE(HOOK_MOUNT_POST,      "hook/mount/post"),	\
 	CHOOSE(HOOK_BASEFS_UP,       "hook/mount/all"),		\
+	CHOOSE(HOOK_SVC_PLUGIN,      "hook/svc/plugin"),	\
 	CHOOSE(HOOK_NETWORK_UP,      "hook/net/up"),		\
 	CHOOSE(HOOK_SVC_UP,          "hook/svc/up"),		\
 	CHOOSE(HOOK_SYSTEM_UP,       "hook/sys/up"),		\