From c516a22e4de2465ea90c8e07a0577ae5ba6fb4ae Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Fri, 30 Nov 2018 20:46:20 -0500
Subject: [PATCH] session-helper: Improve HostCommand life-cycle handling

Add flag that instructs the session-helper to kill
the spawned command when the caller drops off the bus.

Closes: #2326

Closes: #2365
Approved by: alexlarsson
---
 common/flatpak-utils-private.h          |  1 +
 session-helper/flatpak-session-helper.c | 57 ++++++++++++++++++++++++-
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/common/flatpak-utils-private.h b/common/flatpak-utils-private.h
index 54d317b6..156462e2 100644
--- a/common/flatpak-utils-private.h
+++ b/common/flatpak-utils-private.h
@@ -39,6 +39,7 @@
 
 typedef enum {
   FLATPAK_HOST_COMMAND_FLAGS_CLEAR_ENV = 1 << 0,
+  FLATPAK_HOST_COMMAND_FLAGS_WATCH_BUS = 1 << 1,
 } FlatpakHostCommandFlags;
 
 
diff --git a/session-helper/flatpak-session-helper.c b/session-helper/flatpak-session-helper.c
index 7416b0de..396f2471 100644
--- a/session-helper/flatpak-session-helper.c
+++ b/session-helper/flatpak-session-helper.c
@@ -56,6 +56,7 @@ typedef struct
   GPid  pid;
   char *client;
   guint child_watch;
+  gboolean watch_bus;
 } PidData;
 
 static void
@@ -237,7 +238,8 @@ handle_host_command (FlatpakDevelopment    *object,
 
   if (!g_variant_is_of_type (arg_fds, G_VARIANT_TYPE ("a{uh}")) ||
       !g_variant_is_of_type (arg_envs, G_VARIANT_TYPE ("a{ss}")) ||
-      (flags & ~FLATPAK_HOST_COMMAND_FLAGS_CLEAR_ENV) != 0)
+      (flags & ~(FLATPAK_HOST_COMMAND_FLAGS_CLEAR_ENV|
+                 FLATPAK_HOST_COMMAND_FLAGS_WATCH_BUS)) != 0)
     {
       g_dbus_method_invocation_return_error (invocation, G_DBUS_ERROR,
                                              G_DBUS_ERROR_INVALID_ARGS,
@@ -353,6 +355,7 @@ handle_host_command (FlatpakDevelopment    *object,
   pid_data = g_new0 (PidData, 1);
   pid_data->pid = pid;
   pid_data->client = g_strdup (g_dbus_method_invocation_get_sender (invocation));
+  pid_data->watch_bus = (flags & FLATPAK_HOST_COMMAND_FLAGS_WATCH_BUS) != 0;
   pid_data->child_watch = g_child_watch_add_full (G_PRIORITY_DEFAULT,
                                                   pid,
                                                   child_watch_died,
@@ -401,6 +404,48 @@ handle_host_command_signal (FlatpakDevelopment    *object,
   return TRUE;
 }
 
+static void
+name_owner_changed (GDBusConnection *connection,
+                    const gchar     *sender_name,
+                    const gchar     *object_path,
+                    const gchar     *interface_name,
+                    const gchar     *signal_name,
+                    GVariant        *parameters,
+                    gpointer         user_data)
+{
+  const char *name, *from, *to;
+
+  g_variant_get (parameters, "(&s&s&s)", &name, &from, &to);
+
+  if (name[0] == ':' &&
+      strcmp (name, from) == 0 &&
+      strcmp (to, "") == 0)
+    {
+      GHashTableIter iter;
+      PidData *pid_data = NULL;
+      GList *list = NULL, *l;
+
+      g_hash_table_iter_init (&iter, client_pid_data_hash);
+      while (g_hash_table_iter_next (&iter, NULL, (gpointer *)pid_data))
+        {
+          if (pid_data->watch_bus && g_str_equal (pid_data->client, name))
+            list = g_list_prepend (list, pid_data);
+        }
+
+      for (l = list; l; l = l->next)
+        {
+          pid_data = l->data;
+          killpg (pid_data->pid, SIGINT);
+        }
+
+      g_list_free (list);
+    }
+}
+
+#define DBUS_NAME_DBUS "org.freedesktop.DBus"
+#define DBUS_INTERFACE_DBUS DBUS_NAME_DBUS
+#define DBUS_PATH_DBUS "/org/freedesktop/DBus"
+
 static void
 on_bus_acquired (GDBusConnection *connection,
                  const gchar     *name,
@@ -410,6 +455,16 @@ on_bus_acquired (GDBusConnection *connection,
   FlatpakDevelopment *devel;
   GError *error = NULL;
 
+  g_dbus_connection_signal_subscribe (connection,
+                                      DBUS_NAME_DBUS,
+                                      DBUS_INTERFACE_DBUS,
+                                      "NameOwnerChanged",
+                                      DBUS_PATH_DBUS,
+                                      NULL,
+                                      G_DBUS_SIGNAL_FLAGS_NONE,
+                                      name_owner_changed,
+                                      NULL, NULL);
+
   helper = flatpak_session_helper_skeleton_new ();
 
   flatpak_session_helper_set_version (FLATPAK_SESSION_HELPER (helper), 1);