Gerd Hoffmann <[email protected]> writes:
> Add policies for devices which are deprecated or not secure.
> There are three options: allow, warn and deny.
>
> It's implemented for devices only. Devices will probably be the main
> user of this. Also object_new() can't fail as of today so it's a bit
> hard to implement policy checking at object level, especially the 'deny'
> part of it.
>
> TODO: add a command line option to actually set these policies.
>
> Comments are welcome.
>
> Signed-off-by: Gerd Hoffmann <[email protected]>
> ---
> hw/core/qdev.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 59 insertions(+), 1 deletion(-)
>
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index f3a996f57dee..0c4e5cec743c 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -43,6 +43,15 @@
> static bool qdev_hot_added = false;
> bool qdev_hot_removed = false;
>
> +enum qdev_policy {
> + QDEV_ALLOW = 0,
> + QDEV_WARN = 1,
> + QDEV_DENY = 2,
> +};
> +
> +static enum qdev_policy qdev_deprecated_policy;
> +static enum qdev_policy qdev_not_secure_policy;
> +
> const VMStateDescription *qdev_get_vmsd(DeviceState *dev)
> {
> DeviceClass *dc = DEVICE_GET_CLASS(dev);
> @@ -144,6 +153,43 @@ bool qdev_set_parent_bus(DeviceState *dev, BusState
> *bus, Error **errp)
> return true;
> }
>
> +static bool qdev_class_check(const char *name, ObjectClass *oc)
> +{
> + bool allow = true;
> +
> + if (oc->deprecated) {
> + switch (qdev_deprecated_policy) {
> + case QDEV_WARN:
> + warn_report("device \"%s\" is deprecated", name);
> + break;
> + case QDEV_DENY:
> + error_report("device \"%s\" is deprecated", name);
> + allow = false;
> + break;
> + default:
> + /* nothing */
> + break;
> + }
> + }
> +
> + if (oc->not_secure) {
> + switch (qdev_not_secure_policy) {
> + case QDEV_WARN:
> + warn_report("device \"%s\" is not secure", name);
> + break;
> + case QDEV_DENY:
> + error_report("device \"%s\" is not secure", name);
> + allow = false;
> + break;
> + default:
> + /* nothing */
> + break;
> + }
> + }
> +
> + return allow;
> +}
> +
> DeviceState *qdev_new(const char *name)
> {
> ObjectClass *oc = object_class_by_name(name);
> @@ -162,14 +208,26 @@ DeviceState *qdev_new(const char *name)
> error_report("unknown type '%s'", name);
> abort();
> }
> +
> + if (!qdev_class_check(name, oc)) {
Anti-pattern: use of error_report() from within a function that returns
an error via Error **errp argument.
One such call chain: QMP core -> qmp_device_add() -> qdev_device_add()
-> qdev_device_add_from_qdict() -> qdev_new(). Your error message goes
to stderr, which is wrong.
> + exit(1);
Worse, QMP command device_add can now kill the guest instantly.
You need to lift the check up the call chains some.
> + }
> +
> return DEVICE(object_new(name));
> }
>
> DeviceState *qdev_try_new(const char *name)
> {
> - if (!module_object_class_by_name(name)) {
> + ObjectClass *oc = module_object_class_by_name(name);
> +
> + if (!oc) {
> return NULL;
> }
> +
> + if (!qdev_class_check(name, oc)) {
> + return NULL;
> + }
> +
> return DEVICE(object_new(name));
> }
