[Qemu-devel] [PATCH v2 1/2] qdev-properties: add UUID property type

[Roman Kagan <rkagan@virtuozzo.com>]

UUIDs (GUIDs) are widely used in VMBus-related stuff, so a dedicated
property type becomes helpful.

The property accepts a string-formatted UUID or a special keyword "auto"
meaning a randomly generated UUID; the latter is also the default when
the property is not given a value explicitly.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
---
v1 -> v2:
 - make the property default to autogeneration if not specified
   explicitly

 include/hw/qdev-properties.h |  9 +++++++
 hw/core/qdev-properties.c    | 61 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
index e2321f1cc1..efb22ba80c 100644
--- a/include/hw/qdev-properties.h
+++ b/include/hw/qdev-properties.h
@@ -30,6 +30,7 @@ extern const PropertyInfo qdev_prop_vlan;
 extern const PropertyInfo qdev_prop_pci_devfn;
 extern const PropertyInfo qdev_prop_blocksize;
 extern const PropertyInfo qdev_prop_pci_host_devaddr;
+extern const PropertyInfo qdev_prop_uuid;
 extern const PropertyInfo qdev_prop_arraylen;
 extern const PropertyInfo qdev_prop_link;
 
@@ -213,6 +214,14 @@ extern const PropertyInfo qdev_prop_link;
 #define DEFINE_PROP_MEMORY_REGION(_n, _s, _f)             \
     DEFINE_PROP(_n, _s, _f, qdev_prop_ptr, MemoryRegion *)
 
+#define DEFINE_PROP_UUID(_name, _state, _field) {                  \
+        .name      = (_name),                                      \
+        .info      = &qdev_prop_uuid,                              \
+        .offset    = offsetof(_state, _field)                      \
+            + type_check(QemuUUID, typeof_field(_state, _field)),  \
+        .set_default = true,                                       \
+        }
+
 #define DEFINE_PROP_END_OF_LIST()               \
     {}
 
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index 1dc80fcea2..24c17800e3 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -10,6 +10,7 @@
 #include "net/hub.h"
 #include "qapi/visitor.h"
 #include "chardev/char.h"
+#include "qemu/uuid.h"
 
 void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
                                   Error **errp)
@@ -883,6 +884,66 @@ const PropertyInfo qdev_prop_pci_host_devaddr = {
     .set = set_pci_host_devaddr,
 };
 
+/* --- UUID --- */
+
+static void get_uuid(Object *obj, Visitor *v, const char *name, void *opaque,
+                     Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    QemuUUID *uuid = qdev_get_prop_ptr(dev, prop);
+    char buffer[UUID_FMT_LEN + 1];
+    char *p = buffer;
+
+    qemu_uuid_unparse(uuid, buffer);
+
+    visit_type_str(v, name, &p, errp);
+}
+
+#define UUID_VALUE_AUTO        "auto"
+
+static void set_uuid(Object *obj, Visitor *v, const char *name, void *opaque,
+                    Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    QemuUUID *uuid = qdev_get_prop_ptr(dev, prop);
+    Error *local_err = NULL;
+    char *str;
+
+    if (dev->realized) {
+        qdev_prop_set_after_realize(dev, name, errp);
+        return;
+    }
+
+    visit_type_str(v, name, &str, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    if (!strcmp(str, UUID_VALUE_AUTO)) {
+        qemu_uuid_generate(uuid);
+    } else if (qemu_uuid_parse(str, uuid) < 0) {
+        error_set_from_qdev_prop_error(errp, EINVAL, dev, prop, str);
+    }
+    g_free(str);
+}
+
+static void set_default_uuid_auto(Object *obj, const Property *prop)
+{
+    object_property_set_str(obj, UUID_VALUE_AUTO, prop->name, &error_abort);
+}
+
+const PropertyInfo qdev_prop_uuid = {
+    .name  = "str",
+    .description = "UUID (aka GUID) or \"" UUID_VALUE_AUTO
+        "\" for random value (default)",
+    .get   = get_uuid,
+    .set   = set_uuid,
+    .set_default_value = set_default_uuid_auto,
+};
+
 /* --- support for array properties --- */
 
 /* Used as an opaque for the object properties we add for each
-- 
2.14.3