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>
This commit is contained in:
Max Reitz 2014-05-08 20:12:41 +02:00 committed by Kevin Wolf
parent 8a5eb36a1c
commit 4993f7ea7e

41
block.c
View File

@ -1274,6 +1274,33 @@ out:
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 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
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);