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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 22/32] libxl_qmp: Handle messages from QEMU
This will handles messages received, and calls callbacks associated with
the libxl__ev_qmp when the expected response is received.
This also print error messages from QMP on behalf of the callback.
Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
Notes:
v4:
Provide an libxl error code to callbacks on error instead of a
qmp_error_class
tools/libxl/libxl_qmp.c | 116 +++++++++++++++++++++++++++
tools/libxl/libxl_types.idl | 4 +
tools/libxl/libxl_types_internal.idl | 8 ++
3 files changed, 128 insertions(+)
diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c
index aabf9ad5e7..e649b8054d 100644
--- a/tools/libxl/libxl_qmp.c
+++ b/tools/libxl/libxl_qmp.c
@@ -1330,6 +1330,118 @@ static int qmp_ev_prepare_cmd(libxl__gc *gc,
return 0;
}
+/*
+ * Handle messages received from QMP server
+ */
+
+static int qmp_error_class_to_libxl_error_code(const libxl__qmp_error_class c)
+{
+ switch (c) {
+ case LIBXL__QMP_ERROR_CLASS_GENERICERROR:
+ return ERROR_QMP_GENERIC_ERROR;
+ case LIBXL__QMP_ERROR_CLASS_COMMANDNOTFOUND:
+ return ERROR_QMP_COMMAND_NOT_FOUND;
+ case LIBXL__QMP_ERROR_CLASS_DEVICENOTACTIVE:
+ return ERROR_QMP_DEVICE_NOT_ACTIVE;
+ case LIBXL__QMP_ERROR_CLASS_DEVICENOTFOUND:
+ return ERROR_QMP_DEVICE_NOT_FOUND;
+ default:
+ abort();
+ }
+}
+
+/* return 1 when a user callback as been called */
+static int qmp_ev_handle_response(libxl__egc *egc,
+ libxl__ev_qmp *ev,
+ const libxl__json_object *resp,
+ libxl__qmp_message_type type)
+{
+ EGC_GC;
+ const libxl__json_object *response;
+ const libxl__json_object *o;
+ int rc;
+ int id;
+
+ o = libxl__json_map_get("id", resp, JSON_INTEGER);
+ if (!o) {
+ const char *error_desc;
+
+ /* unexpected message, attempt to find an error description */
+ o = libxl__json_map_get("error", resp, JSON_MAP);
+ o = libxl__json_map_get("desc", o, JSON_STRING);
+ error_desc = libxl__json_object_get_string(o);
+ if (error_desc)
+ LOGD(ERROR, ev->domid, "%s", error_desc);
+ else
+ LOGD(ERROR, ev->domid, "Received unexpected message: %s",
+ libxl__json_object_to_json(gc, resp));
+ return 0;
+ }
+
+ id = libxl__json_object_get_integer(o);
+ if (id != ev->id)
+ return 0;
+
+ switch (type) {
+ case LIBXL__QMP_MESSAGE_TYPE_RETURN: {
+ response = libxl__json_map_get("return", resp, JSON_ANY);
+ rc = 0;
+ break;
+ }
+ case LIBXL__QMP_MESSAGE_TYPE_ERROR: {
+ const char *s;
+ const libxl__json_object *err;
+ libxl__qmp_error_class error_class;
+
+ rc = ERROR_FAIL;
+ response = NULL;
+
+ err = libxl__json_map_get("error", resp, JSON_MAP);
+ o = libxl__json_map_get("class", err, JSON_STRING);
+ s = libxl__json_object_get_string(o);
+ if (s && !libxl__qmp_error_class_from_string(s, &error_class))
+ rc = qmp_error_class_to_libxl_error_code(error_class);
+
+ o = libxl__json_map_get("desc", err, JSON_STRING);
+ s = libxl__json_object_get_string(o);
+ if (s)
+ LOGD(ERROR, ev->domid, "%s", s);
+
+ break;
+ }
+ default:
+ abort();
+ }
+
+ ev->id = -1;
+ ev->callback(egc, ev, response, rc); /* must be last */
+ return 1;
+}
+
+/* return 1 when a user callback as been called */
+static int qmp_ev_handle_message(libxl__egc *egc,
+ libxl__ev_qmp *ev,
+ const libxl__json_object *resp)
+{
+ EGC_GC;
+ libxl__qmp_message_type type = qmp_response_type(resp);
+
+ switch (type) {
+ case LIBXL__QMP_MESSAGE_TYPE_QMP:
+ /* greeting message */
+ return 0;
+ case LIBXL__QMP_MESSAGE_TYPE_RETURN:
+ case LIBXL__QMP_MESSAGE_TYPE_ERROR:
+ return qmp_ev_handle_response(egc, ev, resp, type);
+ case LIBXL__QMP_MESSAGE_TYPE_EVENT:
+ /* Event are ignored */
+ return 0;
+ case LIBXL__QMP_MESSAGE_TYPE_INVALID:
+ return 0;
+ }
+ return 0;
+}
+
/*
* QMP FD callbacks
*/
@@ -1432,6 +1544,10 @@ static int qmp_ev_callback_readable(libxl__egc *egc,
libxl__ev_qmp *ev, int fd)
end = NULL;
LOG_QMP("JSON object received: %s", libxl__json_object_to_json(gc, o));
+
+ /* Must be last and return when the user callback is called */
+ if (qmp_ev_handle_message(egc, ev, o) == 1)
+ return 0;
}
return 0;
}
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 4a385801ba..e104fea941 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -69,6 +69,10 @@ libxl_error = Enumeration("error", [
(-23, "NOTFOUND"),
(-24, "DOMAIN_DESTROYED"), # Target domain ceased to exist during op
(-25, "FEATURE_REMOVED"), # For functionality that has been removed
+ (-26, "QMP_GENERIC_ERROR"), # unspecified qmp error
+ (-27, "QMP_COMMAND_NOT_FOUND"), # the requested command has not been found
+ (-28, "QMP_DEVICE_NOT_ACTIVE"), # a device has failed to be become active
+ (-29, "QMP_DEVICE_NOT_FOUND"), # the requested device has not been found
], value_namespace = "")
libxl_domain_type = Enumeration("domain_type", [
diff --git a/tools/libxl/libxl_types_internal.idl
b/tools/libxl/libxl_types_internal.idl
index 37402e49cb..1536d02215 100644
--- a/tools/libxl/libxl_types_internal.idl
+++ b/tools/libxl/libxl_types_internal.idl
@@ -13,6 +13,14 @@ libxl__qmp_message_type = Enumeration("qmp_message_type", [
(5, "invalid"),
])
+libxl__qmp_error_class = Enumeration("qmp_error_class", [
+ # QMP error classes described in QEMU sources code (QapiErrorClass)
+ (1, "GenericError"),
+ (2, "CommandNotFound"),
+ (3, "DeviceNotActive"),
+ (4, "DeviceNotFound"),
+ ])
+
libxl__device_kind = Enumeration("device_kind", [
(0, "NONE"),
(1, "VIF"),
--
Anthony PERARD
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