target/linux/bcm27xx/patches-5.4/950-0648-media-v4l2-dev-Add-v4l2_device_register_ro_subdev_no.patch

   1 From 90712c1a495c2aa4b10dd8127fdd7f1a0cd9ef00 Mon Sep 17 00:00:00 2001
   2 From: Jacopo Mondi <jacopo@jmondi.org>
   3 Date: Tue, 7 Apr 2020 17:21:57 +0200
   4 Subject: [PATCH] media: v4l2-dev: Add
   5  v4l2_device_register_ro_subdev_node()
   6
   7 Add to the V4L2 core a function to register device nodes for video
   8 subdevices in read-only mode.
   9
  10 Registering a device node in read-only mode is useful to expose to
  11 userspace the current sub-device configuration, without allowing
  12 application to change it by using the V4L2 subdevice ioctls.
  13
  14 Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
  15 Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
  16 ---
  17  drivers/media/v4l2-core/v4l2-device.c |  7 ++--
  18  drivers/media/v4l2-core/v4l2-subdev.c | 19 ++++++++++
  19  include/media/v4l2-dev.h              |  7 ++++
  20  include/media/v4l2-device.h           | 50 ++++++++++++++++++++++++---
  21  4 files changed, 77 insertions(+), 6 deletions(-)
  22
  23 --- a/drivers/media/v4l2-core/v4l2-device.c
  24 +++ b/drivers/media/v4l2-core/v4l2-device.c
  25 @@ -189,7 +189,8 @@ static void v4l2_device_release_subdev_n
  26         kfree(vdev);
  27  }
  28
  29 -int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
  30 +int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
  31 +                                       bool read_only)
  32  {
  33         struct video_device *vdev;
  34         struct v4l2_subdev *sd;
  35 @@ -218,6 +219,8 @@ int v4l2_device_register_subdev_nodes(st
  36                 vdev->fops = &v4l2_subdev_fops;
  37                 vdev->release = v4l2_device_release_subdev_node;
  38                 vdev->ctrl_handler = sd->ctrl_handler;
  39 +               if (read_only)
  40 +                       set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
  41                 err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
  42                                               sd->owner);
  43                 if (err < 0) {
  44 @@ -255,7 +258,7 @@ clean_up:
  45
  46         return err;
  47  }
  48 -EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
  49 +EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);
  50
  51  void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
  52  {
  53 --- a/drivers/media/v4l2-core/v4l2-subdev.c
  54 +++ b/drivers/media/v4l2-core/v4l2-subdev.c
  55 @@ -331,6 +331,7 @@ static long subdev_do_ioctl(struct file
  56         struct v4l2_fh *vfh = file->private_data;
  57  #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
  58         struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);
  59 +       bool ro_subdev = test_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
  60         int rval;
  61  #endif
  62
  63 @@ -453,6 +454,9 @@ static long subdev_do_ioctl(struct file
  64         case VIDIOC_SUBDEV_S_FMT: {
  65                 struct v4l2_subdev_format *format = arg;
  66
  67 +               if (format->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)
  68 +                       return -EPERM;
  69 +
  70                 memset(format->reserved, 0, sizeof(format->reserved));
  71                 memset(format->format.reserved, 0, sizeof(format->format.reserved));
  72                 return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->pad, format);
  73 @@ -480,6 +484,9 @@ static long subdev_do_ioctl(struct file
  74                 struct v4l2_subdev_crop *crop = arg;
  75                 struct v4l2_subdev_selection sel;
  76
  77 +               if (crop->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)
  78 +                       return -EPERM;
  79 +
  80                 memset(crop->reserved, 0, sizeof(crop->reserved));
  81                 memset(&sel, 0, sizeof(sel));
  82                 sel.which = crop->which;
  83 @@ -521,6 +528,9 @@ static long subdev_do_ioctl(struct file
  84         case VIDIOC_SUBDEV_S_FRAME_INTERVAL: {
  85                 struct v4l2_subdev_frame_interval *fi = arg;
  86
  87 +               if (ro_subdev)
  88 +                       return -EPERM;
  89 +
  90                 memset(fi->reserved, 0, sizeof(fi->reserved));
  91                 return v4l2_subdev_call(sd, video, s_frame_interval, arg);
  92         }
  93 @@ -544,6 +554,9 @@ static long subdev_do_ioctl(struct file
  94         case VIDIOC_SUBDEV_S_SELECTION: {
  95                 struct v4l2_subdev_selection *sel = arg;
  96
  97 +               if (sel->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev)
  98 +                       return -EPERM;
  99 +
 100                 memset(sel->reserved, 0, sizeof(sel->reserved));
 101                 return v4l2_subdev_call(
 102                         sd, pad, set_selection, subdev_fh->pad, sel);
 103 @@ -580,6 +593,9 @@ static long subdev_do_ioctl(struct file
 104                 return v4l2_subdev_call(sd, video, g_dv_timings, arg);
 105
 106         case VIDIOC_SUBDEV_S_DV_TIMINGS:
 107 +               if (ro_subdev)
 108 +                       return -EPERM;
 109 +
 110                 return v4l2_subdev_call(sd, video, s_dv_timings, arg);
 111
 112         case VIDIOC_SUBDEV_G_STD:
 113 @@ -588,6 +604,9 @@ static long subdev_do_ioctl(struct file
 114         case VIDIOC_SUBDEV_S_STD: {
 115                 v4l2_std_id *std = arg;
 116
 117 +               if (ro_subdev)
 118 +                       return -EPERM;
 119 +
 120                 return v4l2_subdev_call(sd, video, s_std, *std);
 121         }
 122
 123 --- a/include/media/v4l2-dev.h
 124 +++ b/include/media/v4l2-dev.h
 125 @@ -82,11 +82,18 @@ struct v4l2_ctrl_handler;
 126   *     but the old crop API will still work as expected in order to preserve
 127   *     backwards compatibility.
 128   *     Never set this flag for new drivers.
 129 + * @V4L2_FL_SUBDEV_RO_DEVNODE:
 130 + *     indicates that the video device node is registered in read-only mode.
 131 + *     The flag only applies to device nodes registered for sub-devices, it is
 132 + *     set by the core when the sub-devices device nodes are registered with
 133 + *     v4l2_device_register_ro_subdev_nodes() and used by the sub-device ioctl
 134 + *     handler to restrict access to some ioctl calls.
 135   */
 136  enum v4l2_video_device_flags {
 137         V4L2_FL_REGISTERED              = 0,
 138         V4L2_FL_USES_V4L2_FH            = 1,
 139         V4L2_FL_QUIRK_INVERTED_CROP     = 2,
 140 +       V4L2_FL_SUBDEV_RO_DEVNODE       = 3,
 141  };
 142
 143  /* Priority helper functions */
 144 --- a/include/media/v4l2-device.h
 145 +++ b/include/media/v4l2-device.h
 146 @@ -174,14 +174,56 @@ int __must_check v4l2_device_register_su
 147  void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
 148
 149  /**
 150 - * v4l2_device_register_subdev_nodes - Registers device nodes for all subdevs
 151 - *     of the v4l2 device that are marked with
 152 - *     the %V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 153 + * __v4l2_device_register_ro_subdev_nodes - Registers device nodes for
 154 + *      all subdevs of the v4l2 device that are marked with the
 155 + *      %V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 156   *
 157   * @v4l2_dev: pointer to struct v4l2_device
 158 + * @read_only: subdevices read-only flag. True to register the subdevices
 159 + *     device nodes in read-only mode, false to allow full access to the
 160 + *     subdevice userspace API.
 161   */
 162  int __must_check
 163 -v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
 164 +__v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
 165 +                                   bool read_only);
 166 +
 167 +/**
 168 + * v4l2_device_register_subdev_nodes - Registers subdevices device nodes with
 169 + *     unrestricted access to the subdevice userspace operations
 170 + *
 171 + * Internally calls __v4l2_device_register_subdev_nodes(). See its documentation
 172 + * for more details.
 173 + *
 174 + * @v4l2_dev: pointer to struct v4l2_device
 175 + */
 176 +static inline int __must_check
 177 +v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
 178 +{
 179 +#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
 180 +       return __v4l2_device_register_subdev_nodes(v4l2_dev, false);
 181 +#else
 182 +       return 0;
 183 +#endif
 184 +}
 185 +
 186 +/**
 187 + * v4l2_device_register_ro_subdev_nodes - Registers subdevices device nodes
 188 + *     in read-only mode
 189 + *
 190 + * Internally calls __v4l2_device_register_subdev_nodes(). See its documentation
 191 + * for more details.
 192 + *
 193 + * @v4l2_dev: pointer to struct v4l2_device
 194 + */
 195 +static inline int __must_check
 196 +v4l2_device_register_ro_subdev_nodes(struct v4l2_device *v4l2_dev)
 197 +{
 198 +#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
 199 +       return __v4l2_device_register_subdev_nodes(v4l2_dev, true);
 200 +#else
 201 +       return 0;
 202 +#endif
 203 +}
 204
 205  /**
 206   * v4l2_subdev_notify - Sends a notification to v4l2_device.