From c2eb29efe61ffe88d3aff449446a9ac0f0f045a5 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones@redhat.com>
Date: Tue, 2 Jun 2015 09:46:37 +0200
Subject: [PATCH 3/4] block: Allow JSON filenames

Message-id: <1433238397-2500-3-git-send-email-rjones@redhat.com>
Patchwork-id: 65279
O-Subject: [RHEL-7.2 qemu-kvm PATCH 2/2] block: Allow JSON filenames
Bugzilla: 1226697
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>

From: Max Reitz <mreitz@redhat.com>

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>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/block.c b/block.c
index 45543d5..f2caf20 100644
--- a/block.c
+++ b/block.c
@@ -1085,6 +1085,33 @@ static void extract_subqdict(QDict *src, QDict **dst, const char *start)
     }
 }
 
+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, ...)
  *
@@ -1109,6 +1136,20 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
         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);
 
-- 
1.8.3.1