dispatcher: use separate directories for pre-up/pre-down events

To ensure that NetworkManager does not block needlessly for events
which have no scripts, require scripts that respond to blocking
events to opt into the action.

4 files changed, 124 insertions, 31 deletions

diff --git a/callouts/nm-dispatcher-api.h b/callouts/nm-dispatcher-api.h
index 96db789283..eb6b33fe0c 100644
--- a/callouts/nm-dispatcher-api.h
+++ b/callouts/nm-dispatcher-api.h
@@ -20,7 +20,9 @@
 
 #include <dbus/dbus-glib.h>
 
-#define NMD_SCRIPT_DIR NMCONFDIR "/dispatcher.d"
+#define NMD_SCRIPT_DIR   NMCONFDIR "/dispatcher.d"
+#define NMD_PRE_UP_DIR   NMD_SCRIPT_DIR "/pre-up.d"
+#define NMD_PRE_DOWN_DIR NMD_SCRIPT_DIR "/pre-down.d"
 
 /* dbus-glib types for dispatcher call return value */
 #define DISPATCHER_TYPE_RESULT       (dbus_g_type_get_struct ("GValueArray", G_TYPE_STRING, G_TYPE_UINT, G_TYPE_STRING, G_TYPE_INVALID))
@@ -38,6 +40,19 @@
 #define NMD_DEVICE_PROPS_STATE            "state"
 #define NMD_DEVICE_PROPS_PATH             "path"
 
+/* Actions */
+#define NMD_ACTION_HOSTNAME     "hostname"
+#define NMD_ACTION_PRE_UP       "pre-up"
+#define NMD_ACTION_UP           "up"
+#define NMD_ACTION_PRE_DOWN     "pre-down"
+#define NMD_ACTION_DOWN         "down"
+#define NMD_ACTION_VPN_PRE_UP   "vpn-pre-up"
+#define NMD_ACTION_VPN_UP       "vpn-up"
+#define NMD_ACTION_VPN_PRE_DOWN "vpn-pre-down"
+#define NMD_ACTION_VPN_DOWN     "vpn-down"
+#define NMD_ACTION_DHCP4_CHANGE "dhcp4-change"
+#define NMD_ACTION_DHCP6_CHANGE "dhcp6-change"
+
 typedef enum {
 	DISPATCH_RESULT_UNKNOWN = 0,
 	DISPATCH_RESULT_SUCCESS = 1,
diff --git a/callouts/nm-dispatcher.c b/callouts/nm-dispatcher.c
index 3747fd563a..6c9c294f27 100644
--- a/callouts/nm-dispatcher.c
+++ b/callouts/nm-dispatcher.c
@@ -414,16 +414,26 @@ dispatch_one_script (Request *request)
 }
 
 static GSList *
-find_scripts (void)
+find_scripts (const char *str_action)
 {
 	GDir *dir;
 	const char *filename;
 	GSList *sorted = NULL;
 	GError *error = NULL;
+	const char *dirname;
+
+	if (   strcmp (str_action, NMD_ACTION_PRE_UP) == 0
+	    || strcmp (str_action, NMD_ACTION_VPN_PRE_UP) == 0)
+		dirname = NMD_PRE_UP_DIR;
+	else if (   strcmp (str_action, NMD_ACTION_PRE_DOWN) == 0
+	         || strcmp (str_action, NMD_ACTION_VPN_PRE_DOWN) == 0)
+		dirname = NMD_PRE_DOWN_DIR;
+	else
+		dirname = NMD_SCRIPT_DIR;
 
-	if (!(dir = g_dir_open (NMD_SCRIPT_DIR, 0, &error))) {
+	if (!(dir = g_dir_open (dirname, 0, &error))) {
 		g_warning ("Failed to open dispatcher directory '%s': (%d) %s",
-		           NMD_SCRIPT_DIR, error->code, error->message);
+		           dirname, error->code, error->message);
 		g_error_free (error);
 		return NULL;
 	}
@@ -436,7 +446,7 @@ find_scripts (void)
 		if (!check_filename (filename))
 			continue;
 
-		path = g_build_filename (NMD_SCRIPT_DIR, filename, NULL);
+		path = g_build_filename (dirname, filename, NULL);
 
 		err = stat (path, &st);
 		if (err)
@@ -476,7 +486,7 @@ impl_dispatch (Handler *h,
 	char **p;
 	char *iface = NULL;
 
-	sorted_scripts = find_scripts ();
+	sorted_scripts = find_scripts (str_action);
 
 	if (!sorted_scripts) {
 		dbus_g_method_return (context, g_ptr_array_new ());
diff --git a/man/NetworkManager.xml b/man/NetworkManager.xml
index 70e49aa16a..229c390cdc 100644
--- a/man/NetworkManager.xml
+++ b/man/NetworkManager.xml
@@ -53,9 +53,9 @@
     <title>Dispatcher scripts</title>
     <para>
       NetworkManager will execute scripts in the
-      /etc/NetworkManager/dispatcher.d directory in alphabetical order
-      in response to network events.  Each script should be a regular
-      executable file, owned by root.  Furthermore, it must not be
+      /etc/NetworkManager/dispatcher.d directory or subdirectories in
+      alphabetical order in response to network events.  Each script should
+      be a regular executable file owned by root.  Furthermore, it must not be
       writable by group or other, and not setuid.
     </para>
     <para>
@@ -65,22 +65,65 @@
     <para>The actions are:</para>
     <variablelist class="dispatcher-options">
       <varlistentry>
+        <term><varname>pre-up</varname></term>
+        <listitem><para>The interface is connected to the network but is not
+        yet fully activated.  Scripts acting on this event must be placed or
+        symlinked into the /etc/NetworkManager/dispatcher.d/pre-up.d directory,
+        and NetworkManager will wait for script execution to complete before
+        indicating to applications that the interface is fully activated.
+        </para></listitem>
+      </varlistentry>
+      <varlistentry>
         <term><varname>up</varname></term>
         <listitem><para>The interface has been activated.</para></listitem>
       </varlistentry>
       <varlistentry>
+        <term><varname>pre-down</varname></term>
+        <listitem><para>The interface will be deactivated but has not yet been
+        disconnected from the network.  Scripts acting on this event must be
+        placed or symlinked into the /etc/NetworkManager/dispatcher.d/pre-down.d
+        directory, and NetworkManager will wait for script execution to complete
+        before disconnecting the interface from its network.  Note that this
+        event is not emitted for forced disconnections, like when carrier is
+        lost or a wireless signal fades.  It is only emitted when there is
+        an opportunity to cleanly handle a network disconnection event.
+        </para></listitem>
+      </varlistentry>
+      <varlistentry>
         <term><varname>down</varname></term>
         <listitem><para>
           The interface has been deactivated.
         </para></listitem>
       </varlistentry>
       <varlistentry>
+        <term><varname>vpn-pre-up</varname></term>
+        <listitem><para>The VPN is connected to the network but is not yet
+        fully activated.  Scripts acting on this event must be placed or
+        symlinked into the /etc/NetworkManager/dispatcher.d/pre-up.d directory,
+        and NetworkManager will wait for script execution to complete before
+        indicating to applications that the VPN is fully activated.
+        </para></listitem>
+      </varlistentry>
+      <varlistentry>
         <term><varname>vpn-up</varname></term>
         <listitem><para>
           A VPN connection has been activated.
         </para></listitem>
       </varlistentry>
       <varlistentry>
+        <term><varname>vpn-pre-down</varname></term>
+        <listitem><para>The VPN will be deactivated but has not yet been
+        disconnected from the network.  Scripts acting on this event must be
+        placed or symlinked into the /etc/NetworkManager/dispatcher.d/pre-down.d
+        directory, and NetworkManager will wait for script execution to complete
+        before disconnecting the VPN from its network.  Note that this
+        event is not emitted for forced disconnections, like when the VPN
+        terminates unexpectedly or general connectivity is lost.  It is only
+        emitted when there is an opportunity to cleanly handle a VPN
+        disconnection event.
+        </para></listitem>
+      </varlistentry>
+      <varlistentry>
         <term><varname>vpn-down</varname></term>
         <listitem><para>
           A VPN connection has been deactivated.
diff --git a/src/nm-dispatcher.c b/src/nm-dispatcher.c
index 51b9a8a196..29b0329d4a 100644
--- a/src/nm-dispatcher.c
+++ b/src/nm-dispatcher.c
@@ -271,17 +271,17 @@ dispatcher_done_cb (DBusGProxy *proxy, DBusGProxyCall *call, gpointer user_data)
 }
 
 static const char *action_table[] = {
-	[DISPATCHER_ACTION_HOSTNAME]     = "hostname",
-	[DISPATCHER_ACTION_PRE_UP]       = "pre-up",
-	[DISPATCHER_ACTION_UP]           = "up",
-	[DISPATCHER_ACTION_PRE_DOWN]     = "pre-down",
-	[DISPATCHER_ACTION_DOWN]         = "down",
-	[DISPATCHER_ACTION_VPN_PRE_UP]   = "vpn-pre-up",
-	[DISPATCHER_ACTION_VPN_UP]       = "vpn-up",
-	[DISPATCHER_ACTION_VPN_PRE_DOWN] = "vpn-pre-down",
-	[DISPATCHER_ACTION_VPN_DOWN]     = "vpn-down",
-	[DISPATCHER_ACTION_DHCP4_CHANGE] = "dhcp4-change",
-	[DISPATCHER_ACTION_DHCP6_CHANGE] = "dhcp6-change",
+	[DISPATCHER_ACTION_HOSTNAME]     = NMD_ACTION_HOSTNAME,
+	[DISPATCHER_ACTION_PRE_UP]       = NMD_ACTION_PRE_UP,
+	[DISPATCHER_ACTION_UP]           = NMD_ACTION_UP,
+	[DISPATCHER_ACTION_PRE_DOWN]     = NMD_ACTION_PRE_DOWN,
+	[DISPATCHER_ACTION_DOWN]         = NMD_ACTION_DOWN,
+	[DISPATCHER_ACTION_VPN_PRE_UP]   = NMD_ACTION_VPN_PRE_UP,
+	[DISPATCHER_ACTION_VPN_UP]       = NMD_ACTION_VPN_UP,
+	[DISPATCHER_ACTION_VPN_PRE_DOWN] = NMD_ACTION_VPN_PRE_DOWN,
+	[DISPATCHER_ACTION_VPN_DOWN]     = NMD_ACTION_VPN_DOWN,
+	[DISPATCHER_ACTION_DHCP4_CHANGE] = NMD_ACTION_DHCP4_CHANGE,
+	[DISPATCHER_ACTION_DHCP6_CHANGE] = NMD_ACTION_DHCP6_CHANGE,
 };
 
 static const char *
@@ -605,32 +605,57 @@ nm_dispatcher_call_cancel (guint call_id)
 		g_return_if_reached ();
 }
 
+typedef struct {
+	const char *dir;
+	GFileMonitor *monitor;
+	gboolean has_scripts;
+} Monitor;
+
+static Monitor monitors[3] = {
+	{ NMD_SCRIPT_DIR,   NULL, TRUE },
+	{ NMD_PRE_UP_DIR,   NULL, TRUE },
+	{ NMD_PRE_DOWN_DIR, NULL, TRUE }
+};
+
 static void
-dispatcher_dir_changed (GFileMonitor *monitor)
+dispatcher_dir_changed (GFileMonitor *monitor,
+                        GFile *file,
+                        GFile *other_file,
+                        GFileMonitorEvent event_type,
+                        Monitor *item)
 {
 	GDir *dir;
+	guint i;
 
 	/* Default to dispatching on any errors */
-	do_dispatch = TRUE;
-	dir = g_dir_open (NMD_SCRIPT_DIR, 0, NULL);
+	item->has_scripts = TRUE;
+
+	dir = g_dir_open (item->dir, 0, NULL);
 	if (dir) {
-		do_dispatch = !!g_dir_read_name (dir);
+		item->has_scripts = !!g_dir_read_name (dir);
 		g_dir_close (dir);
 	}
+
+	/* Recheck all dirs for scripts and update global variable */
+	do_dispatch = FALSE;
+	for (i = 0; i < G_N_ELEMENTS (monitors); i++)
+		do_dispatch |= monitors[i].has_scripts;
 }
 
 void
 nm_dispatcher_init (void)
 {
 	GFile *file;
-	static GFileMonitor *monitor;
+	guint i;
 
-	file = g_file_new_for_path (NMD_SCRIPT_DIR);
-	monitor = g_file_monitor_directory (file, G_FILE_MONITOR_NONE, NULL, NULL);
-	if (monitor) {
-		g_signal_connect (monitor, "changed", G_CALLBACK (dispatcher_dir_changed), NULL);
-		dispatcher_dir_changed (monitor);
+	for (i = 0; i < G_N_ELEMENTS (monitors); i++) {
+		file = g_file_new_for_path (monitors[i].dir);
+		monitors[i].monitor = g_file_monitor_directory (file, G_FILE_MONITOR_NONE, NULL, NULL);
+		if (monitors[i].monitor) {
+			g_signal_connect (monitors[i].monitor, "changed", G_CALLBACK (dispatcher_dir_changed), &monitors[i]);
+			dispatcher_dir_changed (monitors[i].monitor, file, NULL, 0, &monitors[i]);
+		}
+		g_object_unref (file);
 	}
-	g_object_unref (file);
 }