media: v4l2-compat-ioctl32.c: fix ctrl_is_pointer

commit b8c601e8af2d08f733d74defa8465303391bb930 upstream.

ctrl_is_pointer just hardcoded two known string controls, but that
caused problems when using e.g. custom controls that use a pointer
for the payload.

Reimplement this function: it now finds the v4l2_ctrl (if the driver
uses the control framework) or it calls vidioc_query_ext_ctrl (if the
driver implements that directly).

In both cases it can now check if the control is a pointer control
or not.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
[bwh: Rebased on top of some earlier fixes]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
index 1cde4c5..714dfdc 100644 (file)
--- a/drivers/media/video/v4l2-compat-ioctl32.c
+++ b/drivers/media/video/v4l2-compat-ioctl32.c
@@ -17,6 +17,9 @@
 #include <linux/videodev2.h>
 #include <linux/module.h>
 #include <media/v4l2-ioctl.h>
+#include <media/v4l2-dev.h>
+#include <media/v4l2-fh.h>
+#include <media/v4l2-ctrls.h>
 
 #ifdef CONFIG_COMPAT
 
@@ -572,24 +575,32 @@ struct v4l2_ext_control32 {
        };
 } __attribute__ ((packed));
 
-/* The following function really belong in v4l2-common, but that causes
-   a circular dependency between modules. We need to think about this, but
-   for now this will do. */
-
-/* Return non-zero if this control is a pointer type. Currently only
-   type STRING is a pointer type. */
-static inline int ctrl_is_pointer(u32 id)
+/* Return true if this control is a pointer type. */
+static inline bool ctrl_is_pointer(struct file *file, u32 id)
 {
-       switch (id) {
-       case V4L2_CID_RDS_TX_PS_NAME:
-       case V4L2_CID_RDS_TX_RADIO_TEXT:
-               return 1;
-       default:
-               return 0;
+       struct video_device *vdev = video_devdata(file);
+       struct v4l2_fh *fh = NULL;
+       struct v4l2_ctrl_handler *hdl = NULL;
+
+       if (test_bit(V4L2_FL_USES_V4L2_FH, &vdev->flags))
+               fh = file->private_data;
+
+       if (fh && fh->ctrl_handler)
+               hdl = fh->ctrl_handler;
+       else if (vdev->ctrl_handler)
+               hdl = vdev->ctrl_handler;
+
+       if (hdl) {
+               struct v4l2_ctrl *ctrl = v4l2_ctrl_find(hdl, id);
+
+               return ctrl && ctrl->type == V4L2_CTRL_TYPE_STRING;
        }
+       return false;
 }
 
-static int get_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext_controls32 __user *up)
+static int get_v4l2_ext_controls32(struct file *file,
+                                  struct v4l2_ext_controls *kp,
+                                  struct v4l2_ext_controls32 __user *up)
 {
        struct v4l2_ext_control32 __user *ucontrols;
        struct v4l2_ext_control __user *kcontrols;
@@ -621,7 +632,7 @@ static int get_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext
                        return -EFAULT;
                if (get_user(id, &kcontrols->id))
                        return -EFAULT;
-               if (ctrl_is_pointer(id)) {
+               if (ctrl_is_pointer(file, id)) {
                        void __user *s;
 
                        if (get_user(p, &ucontrols->string))
@@ -636,7 +647,9 @@ static int get_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext
        return 0;
 }
 
-static int put_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext_controls32 __user *up)
+static int put_v4l2_ext_controls32(struct file *file,
+                                  struct v4l2_ext_controls *kp,
+                                  struct v4l2_ext_controls32 __user *up)
 {
        struct v4l2_ext_control32 __user *ucontrols;
        struct v4l2_ext_control __user *kcontrols =
@@ -668,7 +681,7 @@ static int put_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext
                /* Do not modify the pointer when copying a pointer control.
                   The contents of the pointer was changed, not the pointer
                   itself. */
-               if (ctrl_is_pointer(id))
+               if (ctrl_is_pointer(file, id))
                        size -= sizeof(ucontrols->value64);
                if (copy_in_user(ucontrols, kcontrols, size))
                        return -EFAULT;
@@ -832,7 +845,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
        case VIDIOC_G_EXT_CTRLS:
        case VIDIOC_S_EXT_CTRLS:
        case VIDIOC_TRY_EXT_CTRLS:
-               err = get_v4l2_ext_controls32(&karg.v2ecs, up);
+               err = get_v4l2_ext_controls32(file, &karg.v2ecs, up);
                compatible_arg = 0;
                break;
        case VIDIOC_DQEVENT:
@@ -859,7 +872,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
        case VIDIOC_G_EXT_CTRLS:
        case VIDIOC_S_EXT_CTRLS:
        case VIDIOC_TRY_EXT_CTRLS:
-               if (put_v4l2_ext_controls32(&karg.v2ecs, up))
+               if (put_v4l2_ext_controls32(file, &karg.v2ecs, up))
                        err = -EFAULT;
                break;
        }