nm-dispatcher: allow scripts to be marked as no-waitbg/dispatch-sync-requests-rh746703-v2

When a script is a symbolic link to the 'no-wait.d' subdirectory, the
dispatcher now schedules it immediately and in parallel with other
no-wait scripts.

https://bugzilla.gnome.org/show_bug.cgi?id=746703

5 files changed, 126 insertions, 41 deletions

diff --git a/callouts/Makefile.am b/callouts/Makefile.am
index 7bc7273032..c192889ef8 100644
--- a/callouts/Makefile.am
+++ b/callouts/Makefile.am
@@ -95,6 +95,7 @@ install-data-hook:
 	   $(mkinstalldirs) -m 0755 $(DESTDIR)$(dispatcherdir)
 	   $(mkinstalldirs) -m 0755 $(DESTDIR)$(dispatcherdir)/pre-down.d
 	   $(mkinstalldirs) -m 0755 $(DESTDIR)$(dispatcherdir)/pre-up.d
+	   $(mkinstalldirs) -m 0755 $(DESTDIR)$(dispatcherdir)/no-wait.d
 
 CLEANFILES = $(nodist_libnmdbus_dispatcher_la_SOURCES) $(dbusactivation_DATA)
 
diff --git a/callouts/nm-dispatcher-api.h b/callouts/nm-dispatcher-api.h
index e84b08f489..d702ba6851 100644
--- a/callouts/nm-dispatcher-api.h
+++ b/callouts/nm-dispatcher-api.h
@@ -21,6 +21,7 @@
 #define NMD_SCRIPT_DIR_DEFAULT  NMCONFDIR "/dispatcher.d"
 #define NMD_SCRIPT_DIR_PRE_UP   NMD_SCRIPT_DIR_DEFAULT "/pre-up.d"
 #define NMD_SCRIPT_DIR_PRE_DOWN NMD_SCRIPT_DIR_DEFAULT "/pre-down.d"
+#define NMD_SCRIPT_DIR_NO_WAIT  NMD_SCRIPT_DIR_DEFAULT "/no-wait.d"
 
 #define NM_DISPATCHER_DBUS_SERVICE   "org.freedesktop.nm_dispatcher"
 #define NM_DISPATCHER_DBUS_INTERFACE "org.freedesktop.nm_dispatcher"
diff --git a/callouts/nm-dispatcher.c b/callouts/nm-dispatcher.c
index d9fe147f4d..287b2a600c 100644
--- a/callouts/nm-dispatcher.c
+++ b/callouts/nm-dispatcher.c
@@ -31,6 +31,7 @@
 #include <sys/wait.h>
 #include <errno.h>
 #include <arpa/inet.h>
+#include <limits.h>
 
 #include <glib.h>
 #include <glib-unix.h>
@@ -39,6 +40,8 @@
 #include "nm-dispatcher-api.h"
 #include "nm-dispatcher-utils.h"
 #include "nm-glib-compat.h"
+#include "nm-macros-internal.h"
+#include "gsystem-local-alloc.h"
 
 #include "nmdbus-dispatcher.h"
 
@@ -57,6 +60,7 @@ typedef struct {
 
 	Request *current_request;
 	GQueue *pending_requests;
+	guint num_pending;
 } Handler;
 
 typedef struct {
@@ -102,8 +106,6 @@ handler_class_init (HandlerClass *h_class)
 {
 }
 
-static void dispatch_one_script (Request *request);
-
 typedef struct {
 	Request *request;
 
@@ -111,6 +113,10 @@ typedef struct {
 	GPid pid;
 	DispatchResult result;
 	char *error;
+	gboolean wait;
+	gboolean dispatched;
+	guint watch_id;
+	guint timeout_id;
 } ScriptInfo;
 
 struct Request {
@@ -122,13 +128,16 @@ struct Request {
 	char **envp;
 	gboolean debug;
 
-	GPtrArray *scripts;  /* list of ScriptInfo */
+	GPtrArray *scripts;         /* list of ScriptInfo */
 	guint idx;
+	guint num_pending;          /* number of pending scripts */
 
 	guint script_watch_id;
 	guint script_timeout_id;
 };
 
+static void dispatch_one_script (ScriptInfo *script);
+
 static void
 script_info_free (gpointer ptr)
 {
@@ -139,16 +148,6 @@ script_info_free (gpointer ptr)
 	g_free (info);
 }
 
-static void
-request_free (Request *request)
-{
-	g_free (request->action);
-	g_free (request->iface);
-	g_strfreev (request->envp);
-	if (request->scripts)
-		g_ptr_array_free (request->scripts, TRUE);
-}
-
 static gboolean
 quit_timeout_cb (gpointer user_data)
 {
@@ -174,6 +173,22 @@ quit_timeout_reschedule (void)
 }
 
 static void
+request_free (Request *request)
+{
+	g_free (request->action);
+	g_free (request->iface);
+	g_strfreev (request->envp);
+	if (request->scripts)
+		g_ptr_array_free (request->scripts, TRUE);
+
+	g_assert_cmpuint (request->handler->num_pending, >, 0);
+	if (--request->handler->num_pending == 0)
+		quit_timeout_reschedule ();
+
+	g_free (request);
+}
+
+static void
 start_request (Request *request)
 {
 	if (request->iface)
@@ -182,7 +197,7 @@ start_request (Request *request)
 		g_message ("Dispatching action '%s'", request->action);
 
 	request->handler->current_request = request;
-	dispatch_one_script (request);
+	dispatch_one_script (g_ptr_array_index (request->scripts, 0));
 }
 
 static void
@@ -196,23 +211,17 @@ next_request (Handler *h)
 	}
 
 	h->current_request = NULL;
-	quit_timeout_reschedule ();
 }
 
-static gboolean
-next_script (gpointer user_data)
+static void
+complete_request (Request *request)
 {
-	Request *request = user_data;
-	Handler *h = request->handler;
 	GVariantBuilder results;
 	GVariant *ret;
 	guint i;
 
-	request->idx++;
-	if (request->idx < request->scripts->len) {
-		dispatch_one_script (request);
-		return FALSE;
-	}
+	if (request->num_pending || request->idx < request->scripts->len)
+		return;
 
 	/* All done */
 	g_variant_builder_init (&results, G_VARIANT_TYPE ("a(sus)"));
@@ -235,7 +244,21 @@ next_script (gpointer user_data)
 			g_message ("Dispatch '%s' complete", request->action);
 	}
 	request_free (request);
+}
+
+static gboolean
+next_script (gpointer user_data)
+{
+	Request *request = user_data;
+	Handler *h = request->handler;
+
+	request->idx++;
+	if (request->idx < request->scripts->len) {
+		dispatch_one_script (g_ptr_array_index (request->scripts, request->idx));
+		return FALSE;
+	}
 
+	complete_request (request);
 	next_request (h);
 	return FALSE;
 }
@@ -248,9 +271,8 @@ script_watch_cb (GPid pid, gint status, gpointer user_data)
 
 	g_assert (pid == script->pid);
 
-	script->request->script_watch_id = 0;
-	g_source_remove (script->request->script_timeout_id);
-	script->request->script_timeout_id = 0;
+	script->watch_id = 0;
+	nm_clear_g_source (&script->timeout_id);
 
 	if (WIFEXITED (status)) {
 		err = WEXITSTATUS (status);
@@ -280,7 +302,12 @@ script_watch_cb (GPid pid, gint status, gpointer user_data)
 	}
 
 	g_spawn_close_pid (script->pid);
-	next_script (script->request);
+	script->request->num_pending--;
+
+	if (script->wait)
+		next_script (script->request);
+	else
+		complete_request (script->request);
 }
 
 static gboolean
@@ -288,8 +315,7 @@ script_timeout_cb (gpointer user_data)
 {
 	ScriptInfo *script = user_data;
 
-	g_source_remove (script->request->script_watch_id);
-	script->request->script_watch_id = 0;
+	nm_clear_g_source (&script->watch_id);
 	script->request->script_timeout_id = 0;
 
 	g_warning ("Script '%s' took too long; killing it.", script->script);
@@ -305,7 +331,13 @@ again:
 	script->result = DISPATCH_RESULT_TIMEOUT;
 
 	g_spawn_close_pid (script->pid);
-	g_idle_add (next_script, script->request);
+	script->request->num_pending--;
+
+	if (script->wait)
+		g_idle_add (next_script, script->request);
+	else
+		complete_request (script->request);
+
 	return FALSE;
 }
 
@@ -367,11 +399,18 @@ check_filename (const char *file_name)
 #define SCRIPT_TIMEOUT 600  /* 10 minutes */
 
 static void
-dispatch_one_script (Request *request)
+dispatch_one_script (ScriptInfo *script)
 {
 	GError *error = NULL;
 	gchar *argv[4];
-	ScriptInfo *script = g_ptr_array_index (request->scripts, request->idx);
+	Request *request = script->request;
+
+	if (script->dispatched) {
+		g_idle_add (next_script, request);
+		return;
+	}
+
+	script->dispatched = TRUE;
 
 	argv[0] = script->script;
 	argv[1] = request->iface ? request->iface : "none";
@@ -382,8 +421,9 @@ dispatch_one_script (Request *request)
 		g_message ("Running script '%s'", script->script);
 
 	if (g_spawn_async ("/", argv, request->envp, G_SPAWN_DO_NOT_REAP_CHILD, NULL, request, &script->pid, &error)) {
-		request->script_watch_id = g_child_watch_add (script->pid, (GChildWatchFunc) script_watch_cb, script);
-		request->script_timeout_id = g_timeout_add_seconds (SCRIPT_TIMEOUT, script_timeout_cb, script);
+		request->num_pending++;
+		script->watch_id = g_child_watch_add (script->pid, (GChildWatchFunc) script_watch_cb, script);
+		script->timeout_id = g_timeout_add_seconds (SCRIPT_TIMEOUT, script_timeout_cb, script);
 	} else {
 		g_warning ("Failed to execute script '%s': (%d) %s",
 		           script->script, error->code, error->message);
@@ -392,7 +432,8 @@ dispatch_one_script (Request *request)
 		g_clear_error (&error);
 
 		/* Try the next script */
-		g_idle_add (next_script, request);
+		if (script->wait)
+			g_idle_add (next_script, request);
 	}
 }
 
@@ -452,6 +493,34 @@ find_scripts (const char *str_action)
 }
 
 static gboolean
+script_must_wait (const char *path)
+{
+	gs_free char *link = NULL;
+	gs_free char *dir = NULL;
+	gs_free char *real = NULL;
+	char *tmp;
+
+	link = g_file_read_link (path, NULL);
+	if (link) {
+		if (!g_path_is_absolute (link)) {
+			dir = g_path_get_dirname (path);
+			tmp = g_build_path ("/", dir, link, NULL);
+			g_free (link);
+			g_free (dir);
+			link = tmp;
+		}
+
+		dir = g_path_get_dirname (link);
+		real = realpath (dir, NULL);
+
+		if (real && !strcmp (real, NMD_SCRIPT_DIR_NO_WAIT))
+			return FALSE;
+	}
+
+	return TRUE;
+}
+
+static gboolean
 handle_action (NMDBusDispatcher *dbus_dispatcher,
                GDBusMethodInvocation *context,
                const char *str_action,
@@ -474,6 +543,7 @@ handle_action (NMDBusDispatcher *dbus_dispatcher,
 	Request *request;
 	char **p;
 	char *iface = NULL;
+	guint i;
 
 	sorted_scripts = find_scripts (str_action);
 
@@ -514,16 +584,25 @@ handle_action (NMDBusDispatcher *dbus_dispatcher,
 		g_message ("\n");
 	}
 
-	request->iface = g_strdup (iface);
+	request->iface = iface;
 
 	request->scripts = g_ptr_array_new_full (5, script_info_free);
 	for (iter = sorted_scripts; iter; iter = g_slist_next (iter)) {
 		ScriptInfo *s = g_malloc0 (sizeof (*s));
 		s->request = request;
 		s->script = iter->data;
+		s->wait = script_must_wait (s->script);
 		g_ptr_array_add (request->scripts, s);
 	}
 	g_slist_free (sorted_scripts);
+	h->num_pending++;
+
+	for (i = 0; i < request->scripts->len; i++) {
+		ScriptInfo *s = g_ptr_array_index (request->scripts, i);
+
+		if (!s->wait)
+			dispatch_one_script (g_ptr_array_index (request->scripts, i));
+	}
 
 	if (h->current_request)
 		g_queue_push_tail (h->pending_requests, request);
diff --git a/contrib/fedora/rpm/NetworkManager.spec b/contrib/fedora/rpm/NetworkManager.spec
index 5211045801..cdb7bb8e1b 100644
--- a/contrib/fedora/rpm/NetworkManager.spec
+++ b/contrib/fedora/rpm/NetworkManager.spec
@@ -456,6 +456,7 @@ mkdir -p $RPM_BUILD_ROOT%{nmlibdir}/conf.d
 mkdir -p $RPM_BUILD_ROOT%{_sysconfdir}/%{name}/dispatcher.d
 mkdir -p $RPM_BUILD_ROOT%{_sysconfdir}/%{name}/dispatcher.d/pre-up.d
 mkdir -p $RPM_BUILD_ROOT%{_sysconfdir}/%{name}/dispatcher.d/pre-down.d
+mkdir -p $RPM_BUILD_ROOT%{_sysconfdir}/%{name}/dispatcher.d/no-wait.d
 %{__cp} examples/dispatcher/10-ifcfg-rh-routes.sh $RPM_BUILD_ROOT%{_sysconfdir}/%{name}/dispatcher.d/
 %{__ln_s} ../10-ifcfg-rh-routes.sh $RPM_BUILD_ROOT%{_sysconfdir}/%{name}/dispatcher.d/pre-up.d/
 
@@ -524,6 +525,7 @@ fi
 %{_sysconfdir}/%{name}/dispatcher.d/10-ifcfg-rh-routes.sh
 %dir %{_sysconfdir}/%{name}/dispatcher.d/pre-down.d
 %dir %{_sysconfdir}/%{name}/dispatcher.d/pre-up.d
+%dir %{_sysconfdir}/%{name}/dispatcher.d/non-blocking.d
 %{_sysconfdir}/%{name}/dispatcher.d/pre-up.d/10-ifcfg-rh-routes.sh
 %dir %{_sysconfdir}/%{name}/dnsmasq.d
 %dir %{_sysconfdir}/%{name}/VPN
diff --git a/man/NetworkManager.xml b/man/NetworkManager.xml
index ceb810e3b4..1c0572d875 100644
--- a/man/NetworkManager.xml
+++ b/man/NetworkManager.xml
@@ -267,10 +267,12 @@
       Dispatcher scripts are run one at a time, but asynchronously from the main
       NetworkManager process, and will be killed if they run for too long. If your script
       might take arbitrarily long to complete, you should spawn a child process and have the
-      parent return immediately. Also beware that once a script is queued, it will always be
-      run, even if a later event renders it obsolete. (Eg, if an interface goes up, and then
-      back down again quickly, it is possible that one or more "up" scripts will be run
-      after the interface has gone down.)
+      parent return immediately. Scripts that are a link into the
+      /etc/NetworkManager/dispatcher.d/no-wait.d/ directory are run immediately, without
+      waiting for the termination of previous scripts, and in parallel. Also beware that
+      once a script is queued, it will always be run, even if a later event renders it
+      obsolete. (Eg, if an interface goes up, and then back down again quickly, it is
+      possible that one or more "up" scripts will be run after the interface has gone down.)
     </para>
   </refsect1>