[Qemu-devel] [PATCH 1/4] qmp: introduce 'writeconfig' command

[Vadim Galitsyn <vadim.galitsyn@profitbricks.com>]

Add support for `writeconfig' command for QMP monitor.
This is a simple way to keep track of current state of VM
after series of hotplugs and/or hotunplugs of different devices.

Signed-off-by: Vadim Galitsyn <vadim.galitsyn@profitbricks.com>
Signed-off-by: Eduardo Otubo <eduardo.otubo@profitbricks.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Cc: qemu-devel@nongnu.org
---
 qapi-schema.json | 18 ++++++++++++++++++
 qmp.c            | 21 +++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/qapi-schema.json b/qapi-schema.json
index a9dd043f65..083f8f3258 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3200,3 +3200,21 @@
 # Since: 2.11
 ##
 { 'command': 'watchdog-set-action', 'data' : {'action': 'WatchdogAction'} }
+
+##
+# @writeconfig:
+#
+# Dump current configuration into specified file
+#
+# @file: pathname of a file to store current configuration
+#
+# Since: 2.11
+#
+# Example:
+#
+# -> { "execute": "writeconfig",
+#      "arguments": { "file": "/tmp/qemu.conf" } }
+# <- { "return": {} }
+#
+##
+{ 'command': 'writeconfig', 'data': {'file': 'str'} }
diff --git a/qmp.c b/qmp.c
index e8c303116a..fcb911cabb 100644
--- a/qmp.c
+++ b/qmp.c
@@ -722,3 +722,24 @@ MemoryInfo *qmp_query_memory_size_summary(Error **errp)
 
     return mem_info;
 }
+
+void qmp_writeconfig(const char *file, Error **errp)
+{
+    int fd;
+    FILE *fp;
+
+    fd = qemu_open(file,  O_WRONLY | O_CREAT | O_TRUNC, 0600);
+    if (fd != -1) {
+
+        fp = fdopen(fd, "wb");
+        if (fp) {
+            qemu_config_write(fp);
+            fclose(fp);
+            return;
+        }
+
+        qemu_close(fd);
+    }
+
+    error_setg(errp, "cannot write configuration file: '%s'", file);
+}
-- 
2.13.1.394.g41dd433