On Wed, May 02, 2018 at 09:28:35AM -0500, Eric Sandeen wrote:
> On 5/2/18 9:24 AM, Darrick J. Wong wrote:
> > On Tue, May 01, 2018 at 06:04:09PM -0500, Eric Sandeen wrote:
> >> The GET ioctl is trivial, just return the current label.
> >> +static int
> >> +xfs_ioc_getlabel(
> >> + struct xfs_mount *mp,
> >> + char __user *label)
> >> +{
> >> + struct xfs_sb *sbp = &mp->m_sb;
> >> +
> >> + /* Paranoia */
> >> + BUILD_BUG_ON(sizeof(sbp->sb_fname) > FSLABEL_MAX);
> >> +
> >> + if (copy_to_user(label, sbp->sb_fname, sizeof(sbp->sb_fname)))
> >
> > Needs to ensure that a null is set at the end of the (userspace) buffer
> > just in case the label is "123456789012".
>
> Oh, yup!
>
> > There's nothing in the documentation for this ioctl <cough> that says
> > the passed in buffer must already be zeroed.
>
> where /do/ we document ioctls like this, anyway?
man pages. You should really cc linux-api@xxxxxxxxxxxxxxx on any
patch that introduces/hoists a new VFS ioctl, as well as the man
page patch to document it.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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