Instance: mitigate races, add new launch api

Avoid the 3-second 'afterlife' of instances by using
kill (pid, 0) instead of checking the file lock. We
trade pid for lock races, but this seems more reliable.

Also add flatpak_installation_launch_full that returns
a FlatpakInstance for the launched app, and lets us
avoid races around killing the app, by using a child
watch.

Closes: #2221
Approved by: matthiasclasen

1 files changed, 28 insertions, 0 deletions

diff --git a/common/flatpak-instance-private.h b/common/flatpak-instance-private.h
new file mode 100644
index 00000000..64ac6485
--- /dev/null
+++ b/common/flatpak-instance-private.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright © 2018 Red Hat, Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ *       Matthias Clasen
+ */
+
+#ifndef __FLATPAK_INSTANCE_PRIVATE_H__
+#define __FLATPAK_INSTANCE_PRIVATE_H__
+
+#include "flatpak-instance.h"
+
+FlatpakInstance *flatpak_instance_new (const char *dir);
+
+#endif /* __FLATPAK_INSTANCE_PRIVATE_H__ */