On 08/30/2015 05:07 AM, Mauro Carvalho Chehab wrote:
> Add support for the new MEDIA_IOC_G_TOPOLOGY ioctl, according
> with the RFC for the MC next generation.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
>
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index 5b2c9f7fcd45..a91e1ec076a6 100644
> --- a/drivers/media/media-device.c
> +++ b/drivers/media/media-device.c
> @@ -232,6 +232,136 @@ static long media_device_setup_link(struct media_device *mdev,
> return ret;
> }
>
> +static long __media_device_get_topology(struct media_device *mdev,
> + struct media_v2_topology *topo)
> +{
> + struct media_entity *entity;
> + struct media_interface *intf;
> + struct media_pad *pad;
> + struct media_link *link;
> + struct media_v2_entity uentity;
> + struct media_v2_interface uintf;
> + struct media_v2_pad upad;
> + struct media_v2_link ulink;
> + int ret = 0, i;
> +
> + topo->topology_version = mdev->topology_version;
> +
> + /* Get entities and number of entities */
> + i = 0;
> + media_device_for_each_entity(entity, mdev) {
> + i++;
> +
> + if (ret || !topo->entities)
> + continue;
I would add:
if (i > topo->num_entities)
continue;
The copy_to_user can succeed, even if i > num_entities depending on how the
memory was allocated. So I would always check num_entities and refuse to go
beyond it.
> +
> + /* Copy fields to userspace struct if not error */
> + memset(&uentity, 0, sizeof(uentity));
> + uentity.id = entity->graph_obj.id;
> + strncpy(uentity.name, entity->name,
> + sizeof(uentity.name));
> +
> + if (copy_to_user(&topo->entities[i - 1], &uentity, sizeof(uentity)))
> + ret = -EFAULT;
I would just return here. If the user gives bogus values for this, then just
give up.
> + }
> + topo->num_entities = i;
What to do if topo->entities != NULL and i > topo->num_entities? Just return 0
or return ENOSPC? I'm in favor of ENOSPC since a partial topology result is
useless. But if ENOSPC is returned, then all num_foo values should be updated
with the current number of elements.
This behavior would be consistent with e.g. VIDIOC_G_EXT_CTRLS.
> +
> + /* Get interfaces and number of interfaces */
> + i = 0;
> + media_device_for_each_intf(intf, mdev) {
> + i++;
> +
> + if (ret || !topo->interfaces)
> + continue;
> +
> + memset(&uintf, 0, sizeof(uintf));
> +
> + /* Copy intf fields to userspace struct */
> + uintf.id = intf->graph_obj.id;
> + uintf.intf_type = intf->type;
> + uintf.flags = intf->flags;
> +
> + if (media_type(&intf->graph_obj) == MEDIA_GRAPH_INTF_DEVNODE) {
> + struct media_intf_devnode *devnode;
> +
> + devnode = intf_to_devnode(intf);
> +
> + uintf.devnode.major = devnode->major;
> + uintf.devnode.minor = devnode->minor;
> + }
> +
> + if (copy_to_user(&topo->interfaces[i - 1], &uintf, sizeof(uintf)))
> + ret = -EFAULT;
> + }
> + topo->num_interfaces = i;
> +
> + /* Get pads and number of pads */
> + i = 0;
> + media_device_for_each_pad(pad, mdev) {
> + i++;
> +
> + if (ret || !topo->pads)
> + continue;
> +
> + memset(&upad, 0, sizeof(upad));
> +
> + /* Copy pad fields to userspace struct */
> + upad.id = pad->graph_obj.id;
> + upad.entity_id = pad->entity->graph_obj.id;
> + upad.flags = pad->flags;
> +
> + if (copy_to_user(&topo->pads[i - 1], &upad, sizeof(upad)))
> + ret = -EFAULT;
> + }
> + topo->num_pads = i;
> +
> + /* Get links and number of links */
> + i = 0;
> + media_device_for_each_link(link, mdev) {
> + i++;
> +
> + if (ret || !topo->links)
> + continue;
> +
> + memset(&ulink, 0, sizeof(ulink));
> +
> + /* Copy link fields to userspace struct */
> + ulink.id = link->graph_obj.id;
> + ulink.source_id = link->gobj0->id;
> + ulink.sink_id = link->gobj1->id;
> + ulink.flags = link->flags;
> +
> + if (media_type(link->gobj0) != MEDIA_GRAPH_PAD)
> + ulink.flags |= MEDIA_NEW_LNK_FL_INTERFACE_LINK;
> +
> + if (copy_to_user(&topo->links[i - 1], &ulink, sizeof(ulink)))
> + ret = -EFAULT;
> + }
> + topo->num_links = i;
> +
> + return ret;
> +}
> +
> +static long media_device_get_topology(struct media_device *mdev,
> + struct media_v2_topology __user *utopo)
> +{
> + struct media_v2_topology ktopo;
> + int ret;
> +
> + ret = copy_from_user(&ktopo, utopo, sizeof(ktopo));
> +
> + if (ret < 0)
> + return ret;
> +
> + ret = __media_device_get_topology(mdev, &ktopo);
> + if (ret < 0)
> + return ret;
> +
> + ret = copy_to_user(utopo, &ktopo, sizeof(*utopo));
> +
> + return ret;
> +}
> +
> static long media_device_ioctl(struct file *filp, unsigned int cmd,
> unsigned long arg)
> {
> @@ -264,6 +394,13 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd,
> mutex_unlock(&dev->graph_mutex);
> break;
>
> + case MEDIA_IOC_G_TOPOLOGY:
> + mutex_lock(&dev->graph_mutex);
> + ret = media_device_get_topology(dev,
> + (struct media_v2_topology __user *)arg);
> + mutex_unlock(&dev->graph_mutex);
> + break;
> +
> default:
> ret = -ENOIOCTLCMD;
> }
> @@ -312,6 +449,7 @@ static long media_device_compat_ioctl(struct file *filp, unsigned int cmd,
> case MEDIA_IOC_DEVICE_INFO:
> case MEDIA_IOC_ENUM_ENTITIES:
> case MEDIA_IOC_SETUP_LINK:
> + case MEDIA_IOC_G_TOPOLOGY:
> return media_device_ioctl(filp, cmd, arg);
>
> case MEDIA_IOC_ENUM_LINKS32:
>
Note that this will need compat32 code eventually. Should probably be added to the
todo list in the cover letter.
Regards,
Hans
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