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Subject[PATCH v6 16/17] media: uvcvideo: Return -EACCES to inactive controls
Date
If a control is inactive return -EACCES to let the userspace know that
the value will not be applied automatically when the control is active
again.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Suggested-by: Hans Verkuil <hverkuil@xs4all.nl>
---
drivers/media/usb/uvc/uvc_ctrl.c | 73 +++++++++++++++++++++++++-------
drivers/media/usb/uvc/uvc_v4l2.c | 11 ++++-
drivers/media/usb/uvc/uvcvideo.h | 3 +-
3 files changed, 69 insertions(+), 18 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index af1d4d9b8afb..26d3494b401b 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1046,10 +1046,62 @@ static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id,
return 0;
}

-int uvc_ctrl_is_accesible(struct uvc_video_chain *chain, u32 v4l2_id, bool read)
+static bool uvc_ctrl_is_inactive(struct uvc_video_chain *chain,
+ struct uvc_control *ctrl,
+ struct uvc_control_mapping *mapping)
+{
+ struct uvc_control_mapping *master_map = NULL;
+ struct uvc_control *master_ctrl = NULL;
+ s32 val;
+ int ret;
+
+ if (!mapping->master_id)
+ return false;
+
+ __uvc_find_control(ctrl->entity, mapping->master_id, &master_map,
+ &master_ctrl, 0);
+
+ if (!master_ctrl || !(master_ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR))
+ return false;
+
+ ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
+ if (ret < 0 || val == mapping->master_manual)
+ return false;
+
+ return true;
+}
+
+int uvc_ctrl_is_accesible(struct uvc_video_chain *chain, u32 v4l2_id,
+ unsigned long ioctl)
{
struct uvc_control_mapping *mapping;
struct uvc_control *ctrl;
+ bool read, try;
+
+ switch (ioctl) {
+ case VIDIOC_G_EXT_CTRLS:
+ read = true;
+ try = false;
+ break;
+ case VIDIOC_S_EXT_CTRLS:
+ read = false;
+ try = false;
+ break;
+ case VIDIOC_TRY_EXT_CTRLS:
+ read = false;
+ try = true;
+ break;
+ case VIDIOC_G_CTRL:
+ read = true;
+ try = false;
+ break;
+ case VIDIOC_S_CTRL:
+ read = false;
+ try = false;
+ break;
+ default:
+ return -EINVAL;
+ }

if (__uvc_query_v4l2_class(chain, v4l2_id, 0) >= 0)
return -EACCES;
@@ -1064,6 +1116,9 @@ int uvc_ctrl_is_accesible(struct uvc_video_chain *chain, u32 v4l2_id, bool read)
if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) && !read)
return -EACCES;

+ if (!read && !try && uvc_ctrl_is_inactive(chain, ctrl, mapping))
+ return -EACCES;
+
return 0;
}

@@ -1086,8 +1141,6 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
struct uvc_control_mapping *mapping,
struct v4l2_queryctrl *v4l2_ctrl)
{
- struct uvc_control_mapping *master_map = NULL;
- struct uvc_control *master_ctrl = NULL;
const struct uvc_menu_info *menu;
unsigned int i;

@@ -1103,18 +1156,8 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR))
v4l2_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;

- if (mapping->master_id)
- __uvc_find_control(ctrl->entity, mapping->master_id,
- &master_map, &master_ctrl, 0);
- if (master_ctrl && (master_ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR)) {
- s32 val;
- int ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
- if (ret < 0)
- return ret;
-
- if (val != mapping->master_manual)
- v4l2_ctrl->flags |= V4L2_CTRL_FLAG_INACTIVE;
- }
+ if (uvc_ctrl_is_inactive(chain, ctrl, mapping))
+ v4l2_ctrl->flags |= V4L2_CTRL_FLAG_INACTIVE;

if (!ctrl->cached) {
int ret = uvc_ctrl_populate_cache(chain, ctrl);
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index ce55b4bff687..8e9051a245c7 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -999,6 +999,10 @@ static int uvc_ioctl_g_ctrl(struct file *file, void *fh,
struct v4l2_ext_control xctrl;
int ret;

+ ret = uvc_ctrl_is_accesible(chain, ctrl->id, VIDIOC_G_CTRL);
+ if (ret)
+ return ret;
+
memset(&xctrl, 0, sizeof(xctrl));
xctrl.id = ctrl->id;

@@ -1023,6 +1027,10 @@ static int uvc_ioctl_s_ctrl(struct file *file, void *fh,
struct v4l2_ext_control xctrl;
int ret;

+ ret = uvc_ctrl_is_accesible(chain, ctrl->id, VIDIOC_S_CTRL);
+ if (ret)
+ return ret;
+
memset(&xctrl, 0, sizeof(xctrl));
xctrl.id = ctrl->id;
xctrl.value = ctrl->value;
@@ -1054,8 +1062,7 @@ static int uvc_ctrl_check_access(struct uvc_video_chain *chain,
int ret = 0;

for (i = 0; i < ctrls->count; ++ctrl, ++i) {
- ret = uvc_ctrl_is_accesible(chain, ctrl->id,
- ioctl == VIDIOC_G_EXT_CTRLS);
+ ret = uvc_ctrl_is_accesible(chain, ctrl->id, ioctl);
if (ret)
break;
}
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 3288b118264e..4e86d0983d58 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -902,7 +902,8 @@ static inline int uvc_ctrl_rollback(struct uvc_fh *handle)

int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control *xctrl);
int uvc_ctrl_set(struct uvc_fh *handle, struct v4l2_ext_control *xctrl);
-int uvc_ctrl_is_accesible(struct uvc_video_chain *chain, u32 v4l2_id, bool read);
+int uvc_ctrl_is_accesible(struct uvc_video_chain *chain, u32 v4l2_id,
+ unsigned long ioctl);

int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
struct uvc_xu_control_query *xqry);
--
2.31.0.rc2.261.g7f71774620-goog
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