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media: v4l2-dev: Add v4l2_device_register_ro_subdev_node()

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Add to the V4L2 core a function to register device nodes for video
subdevices in read-only mode.

Registering a device node in read-only mode is useful to expose to
userspace the current sub-device configuration, without allowing
application to change it by using the V4L2 subdevice ioctls.

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Jacopo Mondi 2020-05-07 17:12:50 +02:00 committed by Mauro Carvalho Chehab
parent 3fb0ee8b3b
commit f75c431e54
4 changed files with 78 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/media/v4l2-core/v4l2-device.c
View File

@ -186,7 +186,8 @@ static void v4l2_device_release_subdev_node(struct video_device *vdev)
kfree(vdev);
}
int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
bool read_only)
{
struct video_device *vdev;
struct v4l2_subdev *sd;
@ -215,6 +216,8 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
vdev->fops = &v4l2_subdev_fops;
vdev->release = v4l2_device_release_subdev_node;
vdev->ctrl_handler = sd->ctrl_handler;
if (read_only)
set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
sd->owner);
if (err < 0) {
@ -252,7 +255,7 @@ clean_up:
return err;
}
EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
{

19
drivers/media/v4l2-core/v4l2-subdev.c
View File

@ -331,6 +331,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
struct v4l2_fh *vfh = file->private_data;
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);
bool ro_subdev = test_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
#endif
int rval;
@ -477,6 +478,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
case VIDIOC_SUBDEV_S_FMT: {
struct v4l2_subdev_format *format = arg;
if (format->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)
return -EPERM;
memset(format->reserved, 0, sizeof(format->reserved));
memset(format->format.reserved, 0, sizeof(format->format.reserved));
return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
@ -504,6 +508,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
struct v4l2_subdev_crop *crop = arg;
struct v4l2_subdev_selection sel;
if (crop->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)
return -EPERM;
memset(crop->reserved, 0, sizeof(crop->reserved));
memset(&sel, 0, sizeof(sel));
sel.which = crop->which;
@ -545,6 +552,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
case VIDIOC_SUBDEV_S_FRAME_INTERVAL: {
struct v4l2_subdev_frame_interval *fi = arg;
if (ro_subdev)
return -EPERM;
memset(fi->reserved, 0, sizeof(fi->reserved));
return v4l2_subdev_call(sd, video, s_frame_interval, arg);
}
@ -568,6 +578,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
case VIDIOC_SUBDEV_S_SELECTION: {
struct v4l2_subdev_selection *sel = arg;
if (sel->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)
return -EPERM;
memset(sel->reserved, 0, sizeof(sel->reserved));
return v4l2_subdev_call(
sd, pad, set_selection, subdev_fh->pad, sel);
@ -604,6 +617,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
return v4l2_subdev_call(sd, video, g_dv_timings, arg);
case VIDIOC_SUBDEV_S_DV_TIMINGS:
if (ro_subdev)
return -EPERM;
return v4l2_subdev_call(sd, video, s_dv_timings, arg);
case VIDIOC_SUBDEV_G_STD:
@ -612,6 +628,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
case VIDIOC_SUBDEV_S_STD: {
v4l2_std_id *std = arg;
if (ro_subdev)
return -EPERM;
return v4l2_subdev_call(sd, video, s_std, *std);
}

7
include/media/v4l2-dev.h
View File

@ -82,11 +82,18 @@ struct v4l2_ctrl_handler;
* but the old crop API will still work as expected in order to preserve
* backwards compatibility.
* Never set this flag for new drivers.
* @V4L2_FL_SUBDEV_RO_DEVNODE:
* indicates that the video device node is registered in read-only mode.
* The flag only applies to device nodes registered for sub-devices, it is
* set by the core when the sub-devices device nodes are registered with
* v4l2_device_register_ro_subdev_nodes() and used by the sub-device ioctl
* handler to restrict access to some ioctl calls.
*/
enum v4l2_video_device_flags {
V4L2_FL_REGISTERED = 0,
V4L2_FL_USES_V4L2_FH = 1,
V4L2_FL_QUIRK_INVERTED_CROP = 2,
V4L2_FL_SUBDEV_RO_DEVNODE = 3,
};
/* Priority helper functions */

52
include/media/v4l2-device.h
View File

@ -174,14 +174,56 @@ int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
/**
* v4l2_device_register_subdev_nodes - Registers device nodes for all subdevs
* of the v4l2 device that are marked with
* the %V4L2_SUBDEV_FL_HAS_DEVNODE flag.
* __v4l2_device_register_ro_subdev_nodes - Registers device nodes for
* all subdevs of the v4l2 device that are marked with the
* %V4L2_SUBDEV_FL_HAS_DEVNODE flag.
*
* @v4l2_dev: pointer to struct v4l2_device
* @read_only: subdevices read-only flag. True to register the subdevices
* device nodes in read-only mode, false to allow full access to the
* subdevice userspace API.
*/
int __must_check
__v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
bool read_only);
/**
* v4l2_device_register_subdev_nodes - Registers subdevices device nodes with
* unrestricted access to the subdevice userspace operations
*
* Internally calls __v4l2_device_register_subdev_nodes(). See its documentation
* for more details.
*
* @v4l2_dev: pointer to struct v4l2_device
*/
int __must_check
v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
static inline int __must_check
v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
{
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
return __v4l2_device_register_subdev_nodes(v4l2_dev, false);
#else
return 0;
#endif
}
/**
* v4l2_device_register_ro_subdev_nodes - Registers subdevices device nodes
* in read-only mode
*
* Internally calls __v4l2_device_register_subdev_nodes(). See its documentation
* for more details.
*
* @v4l2_dev: pointer to struct v4l2_device
*/
static inline int __must_check
v4l2_device_register_ro_subdev_nodes(struct v4l2_device *v4l2_dev)
{
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
return __v4l2_device_register_subdev_nodes(v4l2_dev, true);
#else
return 0;
#endif
}
/**
* v4l2_subdev_notify - Sends a notification to v4l2_device.