machined: run clone operation asynchronously in the background

Cloning an image can be slow, if the image is not on a btrfs subvolume, hence
let's make sure we do this asynchronously in a child process, so that machined
isn't blocked as long as we process the client request.

This adds a new, generic "Operation" object to machined, that is used to track
these kind of background processes.

This is inspired by the MachineOperation object that already exists to make
copy operations asynchronous. A later patch will rework the MachineOperation
logic to use the generic Operation instead.

1 files changed, 45 insertions, 0 deletions

diff --git a/src/machine/operation.h b/src/machine/operation.h
new file mode 100644
index 0000000000..9d4c3afe45
--- /dev/null
+++ b/src/machine/operation.h
@@ -0,0 +1,45 @@
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2016 Lennart Poettering
+
+  systemd 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.
+
+  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/types.h>
+
+#include "sd-bus.h"
+#include "sd-event.h"
+
+#include "list.h"
+
+typedef struct Operation Operation;
+
+#include "machined.h"
+
+#define OPERATIONS_MAX 64
+
+struct Operation {
+        Manager *manager;
+        pid_t pid;
+        sd_bus_message *message;
+        int errno_fd;
+        sd_event_source *event_source;
+        LIST_FIELDS(Operation, operations);
+};
+
+int operation_new(Manager *m, pid_t child, sd_bus_message *message, int errno_fd);
+Operation *operation_free(Operation *o);