V4L/DVB (12543): v4l: introduce string control support.
The upcoming RDS encoder needs support for string controls. This patch
implements the core implementation.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
index 0056b11..f788c41 100644
--- a/drivers/media/video/v4l2-compat-ioctl32.c
+++ b/drivers/media/video/v4l2-compat-ioctl32.c
@@ -600,9 +600,35 @@
compat_caddr_t controls; /* actually struct v4l2_ext_control32 * */
};
+struct v4l2_ext_control32 {
+ __u32 id;
+ __u32 size;
+ __u32 reserved2[1];
+ union {
+ __s32 value;
+ __s64 value64;
+ compat_caddr_t string; /* actually char * */
+ };
+} __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.
+ *
+ * Note that there are currently no controls of this type, but at least the
+ * compat32 code is in place to properly handle such controls. Please
+ * remove this note once the first pointer controls are added. */
+static inline int ctrl_is_pointer(u32 id)
+{
+ return 0;
+}
+
static int get_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext_controls32 __user *up)
{
- struct v4l2_ext_control __user *ucontrols;
+ struct v4l2_ext_control32 __user *ucontrols;
struct v4l2_ext_control __user *kcontrols;
int n;
compat_caddr_t p;
@@ -626,15 +652,17 @@
kcontrols = compat_alloc_user_space(n * sizeof(struct v4l2_ext_control));
kp->controls = kcontrols;
while (--n >= 0) {
- if (copy_in_user(&kcontrols->id, &ucontrols->id, sizeof(__u32)))
+ if (copy_in_user(kcontrols, ucontrols, sizeof(*kcontrols)))
return -EFAULT;
- if (copy_in_user(&kcontrols->reserved2, &ucontrols->reserved2, sizeof(ucontrols->reserved2)))
- return -EFAULT;
- /* Note: if the void * part of the union ever becomes relevant
- then we need to know the type of the control in order to do
- the right thing here. Luckily, that is not yet an issue. */
- if (copy_in_user(&kcontrols->value, &ucontrols->value, sizeof(ucontrols->value)))
- return -EFAULT;
+ if (ctrl_is_pointer(kcontrols->id)) {
+ void __user *s;
+
+ if (get_user(p, &ucontrols->string))
+ return -EFAULT;
+ s = compat_ptr(p);
+ if (put_user(s, &kcontrols->string))
+ return -EFAULT;
+ }
ucontrols++;
kcontrols++;
}
@@ -643,7 +671,7 @@
static int put_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct v4l2_ext_controls32 __user *up)
{
- struct v4l2_ext_control __user *ucontrols;
+ struct v4l2_ext_control32 __user *ucontrols;
struct v4l2_ext_control __user *kcontrols = kp->controls;
int n = kp->count;
compat_caddr_t p;
@@ -664,15 +692,14 @@
return -EFAULT;
while (--n >= 0) {
- if (copy_in_user(&ucontrols->id, &kcontrols->id, sizeof(__u32)))
- return -EFAULT;
- if (copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
- sizeof(ucontrols->reserved2)))
- return -EFAULT;
- /* Note: if the void * part of the union ever becomes relevant
- then we need to know the type of the control in order to do
- the right thing here. Luckily, that is not yet an issue. */
- if (copy_in_user(&ucontrols->value, &kcontrols->value, sizeof(ucontrols->value)))
+ unsigned size = sizeof(*ucontrols);
+
+ /* 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(kcontrols->id))
+ size -= sizeof(ucontrols->value64);
+ if (copy_in_user(ucontrols, kcontrols, size))
return -EFAULT;
ucontrols++;
kcontrols++;