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[media] v4l: Share code between video_usercopy and video_ioctl2

The two functions are mostly identical. They handle the copy_from_user
and copy_to_user operations related with V4L2 ioctls and call the real
ioctl handler.

Create a __video_usercopy function that implements the core of
video_usercopy and video_ioctl2, and call that function from both.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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pinchartl authored and Mauro Carvalho Chehab committed Jul 12, 2010
1 parent 9f00eda commit fc0a80798576f80ca10b3f6c9c7097f12fd1d64e
Showing with 11 additions and 98 deletions.
  1. +11 −98 drivers/media/video/v4l2-ioctl.c
@@ -294,101 +294,6 @@ void v4l_printk_ioctl(unsigned int cmd)
}
EXPORT_SYMBOL(v4l_printk_ioctl);

/*
* helper function -- handles userspace copying for ioctl arguments
* Obsolete usercopy function - Should be removed soon
*/
long
video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
v4l2_kioctl func)
{
char sbuf[128];
void *mbuf = NULL;
void *parg = NULL;
long err = -EINVAL;
int is_ext_ctrl;
size_t ctrls_size = 0;
void __user *user_ptr = NULL;

is_ext_ctrl = (cmd == VIDIOC_S_EXT_CTRLS || cmd == VIDIOC_G_EXT_CTRLS ||
cmd == VIDIOC_TRY_EXT_CTRLS);

/* Copy arguments into temp kernel buffer */
switch (_IOC_DIR(cmd)) {
case _IOC_NONE:
parg = NULL;
break;
case _IOC_READ:
case _IOC_WRITE:
case (_IOC_WRITE | _IOC_READ):
if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
parg = sbuf;
} else {
/* too big to allocate from stack */
mbuf = kmalloc(_IOC_SIZE(cmd), GFP_KERNEL);
if (NULL == mbuf)
return -ENOMEM;
parg = mbuf;
}

err = -EFAULT;
if (_IOC_DIR(cmd) & _IOC_WRITE)
if (copy_from_user(parg, (void __user *)arg, _IOC_SIZE(cmd)))
goto out;
break;
}
if (is_ext_ctrl) {
struct v4l2_ext_controls *p = parg;

/* In case of an error, tell the caller that it wasn't
a specific control that caused it. */
p->error_idx = p->count;
user_ptr = (void __user *)p->controls;
if (p->count) {
ctrls_size = sizeof(struct v4l2_ext_control) * p->count;
/* Note: v4l2_ext_controls fits in sbuf[] so mbuf is still NULL. */
mbuf = kmalloc(ctrls_size, GFP_KERNEL);
err = -ENOMEM;
if (NULL == mbuf)
goto out_ext_ctrl;
err = -EFAULT;
if (copy_from_user(mbuf, user_ptr, ctrls_size))
goto out_ext_ctrl;
p->controls = mbuf;
}
}

/* call driver */
err = func(file, cmd, parg);
if (err == -ENOIOCTLCMD)
err = -EINVAL;
if (is_ext_ctrl) {
struct v4l2_ext_controls *p = parg;

p->controls = (void *)user_ptr;
if (p->count && err == 0 && copy_to_user(user_ptr, mbuf, ctrls_size))
err = -EFAULT;
goto out_ext_ctrl;
}
if (err < 0)
goto out;

out_ext_ctrl:
/* Copy results into user buffer */
switch (_IOC_DIR(cmd)) {
case _IOC_READ:
case (_IOC_WRITE | _IOC_READ):
if (copy_to_user((void __user *)arg, parg, _IOC_SIZE(cmd)))
err = -EFAULT;
break;
}

out:
kfree(mbuf);
return err;
}
EXPORT_SYMBOL(video_usercopy);

static void dbgbuf(unsigned int cmd, struct video_device *vfd,
struct v4l2_buffer *p)
{
@@ -2332,8 +2237,9 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
return ret;
}

long video_ioctl2(struct file *file,
unsigned int cmd, unsigned long arg)
long
video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
v4l2_kioctl func)
{
char sbuf[128];
void *mbuf = NULL;
@@ -2395,7 +2301,7 @@ long video_ioctl2(struct file *file,
}

/* Handles IOCTL */
err = __video_do_ioctl(file, cmd, parg);
err = func(file, cmd, parg);
if (err == -ENOIOCTLCMD)
err = -EINVAL;

@@ -2422,4 +2328,11 @@ long video_ioctl2(struct file *file,
kfree(mbuf);
return err;
}
EXPORT_SYMBOL(video_usercopy);

long video_ioctl2(struct file *file,
unsigned int cmd, unsigned long arg)
{
return video_usercopy(file, cmd, arg, __video_do_ioctl);
}
EXPORT_SYMBOL(video_ioctl2);

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