On Thu, Jul 10, 2025 at 10:26:45AM +0300, Mike Rapoport wrote:
> IIUC Christian's point was mostly not about using VFS APIs (i.e.
> read/write) but about using a special pseudo fs rather than devtmpfs to
> drive ioctls.
>
> So instead of
>
> fd = open("/dev/liveupdate", ...);
> ioctl(fd, ...);
>
> we'd use
>
> fd = open("/sys/fs/kexec/control", ...);
> ioctl(fd, ...);
Please no, /sys/ is much worse.
/dev/ has lots of infrastructure to control permissions/etc that /sys/
does not.
If you want to do ioctls to something that you open() is a character
dev and you accept the limitations with namespaces, coarse permissions
and so on.
Jason
