block: Allow JSON filenames
If the filename given to bdrv_open() is prefixed with "json:", parse the
rest as a JSON object and merge the result into the options QDict. If
there are conflicts, the options QDict takes precedence.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 65e8191..415ae3d 100644
--- a/block.c
+++ b/block.c
@@ -1274,6 +1274,33 @@
g_free(tmp_filename);
}
+static QDict *parse_json_filename(const char *filename, Error **errp)
+{
+ QObject *options_obj;
+ QDict *options;
+ int ret;
+
+ ret = strstart(filename, "json:", &filename);
+ assert(ret);
+
+ options_obj = qobject_from_json(filename);
+ if (!options_obj) {
+ error_setg(errp, "Could not parse the JSON options");
+ return NULL;
+ }
+
+ if (qobject_type(options_obj) != QTYPE_QDICT) {
+ qobject_decref(options_obj);
+ error_setg(errp, "Invalid JSON object given");
+ return NULL;
+ }
+
+ options = qobject_to_qdict(options_obj);
+ qdict_flatten(options);
+
+ return options;
+}
+
/*
* Opens a disk image (raw, qcow2, vmdk, ...)
*
@@ -1337,6 +1364,20 @@
options = qdict_new();
}
+ if (filename && g_str_has_prefix(filename, "json:")) {
+ QDict *json_options = parse_json_filename(filename, &local_err);
+ if (local_err) {
+ ret = -EINVAL;
+ goto fail;
+ }
+
+ /* Options given in the filename have lower priority than options
+ * specified directly */
+ qdict_join(options, json_options, false);
+ QDECREF(json_options);
+ filename = NULL;
+ }
+
bs->options = options;
options = qdict_clone_shallow(options);
