Attachment 65246 Details for Bug 53220 – Avoid race between Mission Control's two names by having one wait for the other

[patch] Avoid race between Mission Control's two names by having one wait for the other

0001-Avoid-race-between-Mission-Control-s-two-names-by-ha.patch (text/plain), 6.08 KB, created by Simon McVittie on 2012-08-07 18:59:16 UTC

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Creator: Simon McVittie

Created: 2012-08-07 18:59:16 UTC

Size: 6.08 KB

patch

obsolete

>From a9cf88f29cea7febfc0dea6244ee37b2955d0970 Mon Sep 17 00:00:00 2001
>From: Simon McVittie <simon.mcvittie@collabora.co.uk>
>Date: Tue, 7 Aug 2012 19:48:09 +0100
>Subject: [PATCH] Avoid race between Mission Control's two names by having one
> wait for the other
>
>If you do:
>
>dbus-send --dest=org.freedesktop.Telepathy.MissionControl5 \
>  --type=method_call --print-reply / org.freedesktop.DBus.Peer.Ping & \
>dbus-send --dest=org.freedesktop.Telepathy.AccountManager \
>--type=method_call --print-reply / org.freedesktop.DBus.Peer.Ping
>
>then one or both of the calls will fail because the executable claims
>one of its bus names, but can't get the other, and exits 1.
>
>By making one wait for the other, we get the desired behaviour.
>I've made activating MissionControl5 wait for AccountManager because
>in MC's current implementation AccountManager is taken last.
>---
> server/Makefile.am                                 |    5 +-
> ...reedesktop.Telepathy.MissionControl5.service.in |    2 +-
> util/wait-for-name.c                               |   87 ++++++++++++++++++--
> 3 files changed, 86 insertions(+), 8 deletions(-)
>
>diff --git a/server/Makefile.am b/server/Makefile.am
>index ba73450..eb74a3c 100644
>--- a/server/Makefile.am
>+++ b/server/Makefile.am
>@@ -24,7 +24,10 @@ servicefile_DATA=org.freedesktop.Telepathy.MissionControl5.service \
> 		 org.freedesktop.Telepathy.AccountManager.service
> 
> %.service: %.service.in Makefile
>-	$(AM_V_GEN)sed -e 's![@]libexecdir[@]!$(libexecdir)!' $< > $@
>+	$(AM_V_GEN)sed \
>+		-e 's![@]libexecdir[@]!$(libexecdir)!' \
>+		-e 's![@]bindir[@]!$(bindir)!' \
>+		$< > $@
> 
> man8_MANS = mission-control-5.8
> 
>diff --git a/server/org.freedesktop.Telepathy.MissionControl5.service.in b/server/org.freedesktop.Telepathy.MissionControl5.service.in
>index d91d4dd..51f4dc1 100644
>--- a/server/org.freedesktop.Telepathy.MissionControl5.service.in
>+++ b/server/org.freedesktop.Telepathy.MissionControl5.service.in
>@@ -1,3 +1,3 @@
> [D-BUS Service]
> Name=org.freedesktop.Telepathy.MissionControl5
>-Exec=@libexecdir@/mission-control-5
>+Exec=@bindir@/mc-wait-for-name --activate org.freedesktop.Telepathy.AccountManager org.freedesktop.Telepathy.MissionControl5
>diff --git a/util/wait-for-name.c b/util/wait-for-name.c
>index af8bcdb..4679a18 100644
>--- a/util/wait-for-name.c
>+++ b/util/wait-for-name.c
>@@ -4,14 +4,22 @@
>  * automatically (after a while) by the desktop session.
>  *
>  * Usage, in
>- * $XDG_DATA_DIRS/dbus-1/services/org.freedesktop.Client.Something.service:
>+ * $XDG_DATA_DIRS/dbus-1/services/....Client.Something.service:
>  *
>  * [D-BUS Service]
>- * Name=org.freedesktop.Telepathy.Client.Something
>- * Exec=/usr/lib/mission-control/mc-wait-for-name org.freedesktop.Telepathy.Client.Something
>+ * Name=....Client.Something
>+ * Exec=/usr/lib/telepathy/mc-wait-for-name ....Client.Something
>+ *
>+ * Alternatively, it can be used to activate something via an alternative
>+ * name, e.g. in
>+ * $XDG_DATA_DIRS/dbus-1/services/....AccountManager.service:
>+ *
>+ * [D-BUS Service]
>+ * Name=....AccountManager
>+ * Exec=/usr/lib/telepathy/mc-wait-for-name --activate ....MissionControl5 ....AccountManager
>  *
>  * Copyright (C) 2009 Nokia Corporation
>- * Copyright (C) 2009 Collabora Ltd.
>+ * Copyright (C) 2009, 2012 Collabora Ltd.
>  *
>  * This library is free software; you can redistribute it and/or
>  * modify it under the terms of the GNU Lesser General Public
>@@ -41,7 +49,7 @@
> 
> #include <glib.h>
> 
>-#include <telepathy-glib/dbus.h>
>+#include <telepathy-glib/telepathy-glib.h>
> 
> static int exit_status = EX_SOFTWARE;
> static guint timeout_id = 0;
>@@ -86,8 +94,48 @@ noc_cb (TpDBusDaemon *bus_daemon,
>     }
> }
> 
>+static void
>+start_service_cb (TpDBusDaemon *bus_daemon,
>+    guint ret,
>+    const GError *error,
>+    gpointer user_data,
>+    GObject *weak_object)
>+{
>+  GMainLoop *loop = user_data;
>+
>+  if (error != NULL)
>+    {
>+      g_message ("%s", error->message);
>+      g_main_loop_quit (loop);
>+      exit_status = EX_TEMPFAIL;
>+    }
>+  else
>+    {
>+      switch (ret)
>+        {
>+          case 1: /* DBUS_START_REPLY_SUCCESS */
>+            g_debug ("activated name successfully started");
>+            break;
>+
>+          case 2: /* DBUS_START_REPLY_ALREADY_RUNNING */
>+            g_debug ("activated name already running");
>+            break;
>+
>+          default:
>+            g_message ("ignoring unknown result from StartServiceByName: %u", ret);
>+            break;
>+        }
>+    }
>+}
>+
> #define WFN_TIMEOUT (5 * 60) /* 5 minutes */
> 
>+static gchar *activate = NULL;
>+static GOptionEntry entries[] = {
>+      { "activate", 0, 0, G_OPTION_ARG_STRING, &activate, "Activate NAME before waiting for the other name", "NAME" },
>+      { NULL }
>+};
>+
> int
> main (int argc,
>       char **argv)
>@@ -95,14 +143,33 @@ main (int argc,
>   TpDBusDaemon *bus_daemon;
>   GMainLoop *loop;
>   GError *error = NULL;
>+  GOptionContext *context;
> 
>   g_set_prgname ("mc-wait-for-name");
> 
>+  context = g_option_context_new ("- wait for a bus name");
>+  g_option_context_add_main_entries (context, entries, NULL);
>+
>+  if (!g_option_context_parse (context, &argc, &argv, &error))
>+    {
>+      g_message ("%s", error->message);
>+      g_error_free (error);
>+      return EX_USAGE;
>+    }
>+
>+  if (activate != NULL &&
>+      !tp_dbus_check_valid_bus_name (activate, TP_DBUS_NAME_TYPE_WELL_KNOWN,
>+        NULL))
>+    {
>+      g_message ("Not a valid bus name: %s", activate);
>+      return EX_USAGE;
>+    }
>+
>   if (argc != 2 ||
>       !tp_dbus_check_valid_bus_name (argv[1], TP_DBUS_NAME_TYPE_WELL_KNOWN,
>         NULL))
>     {
>-      g_message ("Usage: mc-wait-for-name com.example.SomeBusName");
>+      g_message ("Usage: mc-wait-for-name [OPTIONS] com.example.SomeBusName");
>       return EX_USAGE;
>     }
> 
>@@ -117,6 +184,14 @@ main (int argc,
>     }
> 
>   loop = g_main_loop_new (NULL, FALSE);
>+
>+  if (activate != NULL)
>+    {
>+      tp_cli_dbus_daemon_call_start_service_by_name (bus_daemon, -1,
>+          activate, 0 /* no flags */, start_service_cb, g_main_loop_ref (loop),
>+          (GDestroyNotify) g_main_loop_unref, NULL);
>+    }
>+
>   tp_dbus_daemon_watch_name_owner (bus_daemon, argv[1],
>       noc_cb, g_main_loop_ref (loop), (GDestroyNotify) g_main_loop_unref);
> 
>-- 
>1.7.10.4
>

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