qemu-ga: switch to the new error format on the wire

IMPORTANT: this BREAKS qemu-ga compatibility for the error response.

Instead of returning something like:

{ "error": { "class": "InvalidParameterValue",
             "data": {"name": "mode", "expected": "halt|powerdown|reboot" } } }

qemu-ga now returns:

 { "error": { "class": "GenericError",
              "desc": "Parameter 'mode' expects halt|powerdown|reboot" } }

Notice that this is also a bug fix, as qemu-ga wasn't returning the
human message.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

2 files changed, 10 insertions, 1 deletions

diff --git a/qapi/qmp-core.h b/qapi/qmp-core.h
index b0f64ba1ee..00446cff9b 100644
--- a/qapi/qmp-core.h
+++ b/qapi/qmp-core.h
@@ -49,6 +49,7 @@ void qmp_disable_command(const char *name);
 void qmp_enable_command(const char *name);
 bool qmp_command_is_enabled(const char *name);
 char **qmp_get_command_list(void);
+QObject *qmp_build_error_object(Error *errp);
 
 #endif
 
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
index 122c1a29ba..ec613f88b5 100644
--- a/qapi/qmp-dispatch.c
+++ b/qapi/qmp-dispatch.c
@@ -14,6 +14,7 @@
 #include "qemu-objects.h"
 #include "qapi/qmp-core.h"
 #include "json-parser.h"
+#include "qapi-types.h"
 #include "error.h"
 #include "error_int.h"
 #include "qerror.h"
@@ -109,6 +110,13 @@ static QObject *do_qmp_dispatch(QObject *request, Error **errp)
     return ret;
 }
 
+QObject *qmp_build_error_object(Error *errp)
+{
+    return qobject_from_jsonf("{ 'class': %s, 'desc': %s }",
+                              ErrorClass_lookup[error_get_class(errp)],
+                              error_get_pretty(errp));
+}
+
 QObject *qmp_dispatch(QObject *request)
 {
     Error *err = NULL;
@@ -119,7 +127,7 @@ QObject *qmp_dispatch(QObject *request)
 
     rsp = qdict_new();
     if (err) {
-        qdict_put_obj(rsp, "error", error_get_qobject(err));
+        qdict_put_obj(rsp, "error", qmp_build_error_object(err));
         error_free(err);
     } else if (ret) {
         qdict_put_obj(rsp, "return", ret);