Re: [PATCH v2 09/15] softmmu/qdev-monitor: add error handling in qdev_set_id

From: Damien Hedde <damien.hedde(a)greensocs.com&gt; qdev_set_id() is mostly used when the user adds a device (using -device cli option or device_add qmp command). This commit adds an error parameter to handle the case where the given id is already taken. Also document the function and add a return value in order to be able to capture success/failure: the function now returns the id in case of success, or NULL in case of failure. The commit modifies the 2 calling places (qdev-monitor and xen-legacy-backend) to add the error object parameter. Note that the id is, right now, guaranteed to be unique because all ids came from the "device" QemuOptsList where the id is used as key. This addition is a preparation for a future commit which will relax the uniqueness. Signed-off-by: Damien Hedde <damien.hedde(a)greensocs.com&gt; Signed-off-by: Kevin Wolf <kwolf(a)redhat.com&gt; ---

+++ b/softmmu/qdev-monitor.c @@ -593,22 +593,34 @@ static BusState *qbus_find(const char *path, Error **errp) } /* Takes ownership of @id, will be freed when deleting the device */ -void qdev_set_id(DeviceState *dev, char *id) +const char *qdev_set_id(DeviceState *dev, char *id, Error **errp) { - if (id) { - dev->id = id; - } + ObjectProperty *prop; - if (dev->id) { - object_property_add_child(qdev_get_peripheral(), dev->id, - OBJECT(dev)); + assert(!dev->id && !dev->realized); + + /* + * object_property_[try_]add_child() below will assert the device + * has no parent + */ + if (id) { + prop = object_property_try_add_child(qdev_get_peripheral(), id, + OBJECT(dev), NULL); + if (prop) { + dev->id = id; + } else { + error_setg(errp, "Duplicate device ID '%s'", id); + return NULL;

+ } } else { static int anon_count; gchar *name = g_strdup_printf("device[%d]", anon_count++); - object_property_add_child(qdev_get_peripheral_anon(), name, - OBJECT(dev)); + prop = object_property_add_child(qdev_get_peripheral_anon(), name, + OBJECT(dev)); g_free(name); } + + return prop->name; } DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) @@ -691,7 +703,13 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) } } - qdev_set_id(dev, g_strdup(qemu_opts_id(opts))); + /* + * set dev's parent and register its id. + * If it fails it means the id is already taken. + */ + if (!qdev_set_id(dev, g_strdup(qemu_opts_id(opts)), errp)) { + goto err_del_dev;

+ } /* set properties */ if (qemu_opt_foreach(opts, set_property, dev, errp)) { -- 2.31.1