[Qemu-devel] [PATCH 6/6] qdev: Generate IDs for anonymous devices

[Jan Kiszka]

In order to address devices for that the user forgot or is even unable
(no_user) to provide an ID, assign an automatically generated one. Such
IDs have the format #<number>, thus are outside the name space availing
to users. Don't use them for bus naming to avoid any other user-visible
change.

CC: Markus Armbruster <address@hidden>
Signed-off-by: Jan Kiszka <address@hidden>
---
 hw/qdev-properties.c |    2 +-
 hw/qdev.c            |   25 +++++++++++++------------
 hw/qdev.h            |    1 +
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index 0c0c292..4e39cef 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -682,7 +682,7 @@ int qdev_prop_set_drive(DeviceState *dev, const char *name, 
BlockDriverState *va
     if (res < 0) {
         error_report("Can't attach drive %s to %s.%s: %s",
                      bdrv_get_device_name(value),
-                     dev->id ? dev->id : dev->info->name,
+                     dev->id != dev->auto_id ? dev->id : dev->info->name,
                      name, strerror(-res));
         return -1;
     }
diff --git a/hw/qdev.c b/hw/qdev.c
index 3b0e1af..807902b 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -85,6 +85,7 @@ static DeviceInfo *qdev_find_info(BusInfo *bus_info, const 
char *name)
 
 static DeviceState *qdev_create_from_info(BusState *bus, DeviceInfo *info)
 {
+    static unsigned int auto_id;
     DeviceState *dev;
 
     assert(bus->info == info->bus_info);
@@ -94,6 +95,8 @@ static DeviceState *qdev_create_from_info(BusState *bus, 
DeviceInfo *info)
     qdev_prop_set_defaults(dev, dev->info->props);
     qdev_prop_set_defaults(dev, dev->parent_bus->info->props);
     qdev_prop_set_globals(dev);
+    snprintf(dev->auto_id, sizeof(dev->auto_id), "#%u", ++auto_id);
+    dev->id = dev->auto_id;
     QLIST_INSERT_HEAD(&bus->children, dev, sibling);
     if (qdev_hotplug) {
         assert(bus->allow_hotplug);
@@ -574,8 +577,9 @@ DeviceState *qdev_find_recursive(BusState *bus, const char 
*id)
     BusState *child;
 
     QLIST_FOREACH(dev, &bus->children, sibling) {
-        if (dev->id && strcmp(dev->id, id) == 0)
+        if (strcmp(dev->id, id) == 0) {
             return dev;
+        }
         QLIST_FOREACH(child, &dev->child_bus, sibling) {
             ret = qdev_find_recursive(child, id);
             if (ret) {
@@ -591,8 +595,8 @@ static void qbus_list_bus(DeviceState *dev)
     BusState *child;
     const char *sep = " ";
 
-    error_printf("child busses at \"%s\":",
-                 dev->id ? dev->id : dev->info->name);
+    error_printf("child busses at \"%s\"/\"%s\":",
+                 dev->info->name, dev->id);
     QLIST_FOREACH(child, &dev->child_bus, sibling) {
         error_printf("%s\"%s\"", sep, child->name);
         sep = ", ";
@@ -607,9 +611,7 @@ static void qbus_list_dev(BusState *bus)
 
     error_printf("devices at \"%s\":", bus->name);
     QLIST_FOREACH(dev, &bus->children, sibling) {
-        error_printf("%s\"%s\"", sep, dev->info->name);
-        if (dev->id)
-            error_printf("/\"%s\"", dev->id);
+        error_printf("%s\"%s\"/\"%s\"", sep, dev->info->name, dev->id);
         sep = ", ";
     }
     error_printf("\n");
@@ -638,7 +640,7 @@ static DeviceState *qbus_find_dev(BusState *bus, char *elem)
      *   (3) driver alias, if present
      */
     QLIST_FOREACH(dev, &bus->children, sibling) {
-        if (dev->id  &&  strcmp(dev->id, elem) == 0) {
+        if (strcmp(dev->id, elem) == 0) {
             return dev;
         }
     }
@@ -754,8 +756,8 @@ void qbus_create_inplace(BusState *bus, BusInfo *info,
     if (name) {
         /* use supplied name */
         bus->name = g_strdup(name);
-    } else if (parent && parent->id) {
-        /* parent device has id -> use it for bus name */
+    } else if (parent && parent->id != parent->auto_id) {
+        /* parent device has user-assigned id -> use it for bus name */
         len = strlen(parent->id) + 16;
         buf = g_malloc(len);
         snprintf(buf, len, "%s.%d", parent->id, parent->num_child_bus);
@@ -850,8 +852,7 @@ static void qdev_print_props(Monitor *mon, DeviceState 
*dev, Property *props,
 static void qdev_print(Monitor *mon, DeviceState *dev, int indent)
 {
     BusState *child;
-    qdev_printf("dev: %s, id \"%s\"\n", dev->info->name,
-                dev->id ? dev->id : "");
+    qdev_printf("dev: %s, id \"%s\"\n", dev->info->name, dev->id);
     indent += 2;
     if (dev->num_gpio_in) {
         qdev_printf("gpio-in %d\n", dev->num_gpio_in);
@@ -1196,7 +1197,7 @@ int do_device_show(Monitor *mon, const QDict *qdict, 
QObject **ret_data)
     name = g_malloc(name_len);
     snprintf(name, name_len, "%s", dev->info->name);
     *ret_data = qobject_from_jsonf("{ 'device': %s, 'id': %s, 'version': %d }",
-                                   name, dev->id ? : "", vmsd->version_id);
+                                   name, dev->id, vmsd->version_id);
     g_free(name);
     qlist = qlist_new();
     parse_vmstate(vmsd, dev, qlist, qdict_get_try_bool(qdict, "full", false));
diff --git a/hw/qdev.h b/hw/qdev.h
index 912fc45..d028409 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -31,6 +31,7 @@ enum {
    so that it can be embedded in individual device state structures.  */
 struct DeviceState {
     const char *id;
+    char auto_id[16];
     enum DevState state;
     QemuOpts *opts;
     int hotplugged;
-- 
1.7.3.4