Re: [PATCH glibc] Linux: Include <linux/sockios.h> in <bits/socket.h> under __USE_MISC

[Szabolcs Nagy <Szabolcs.Nagy@arm.com>]

On 22/07/2019 12:34, Arnd Bergmann wrote:
> On Mon, Jul 22, 2019 at 1:31 PM Florian Weimer <fweimer@redhat.com> wrote:
>>
>> Historically, <asm/socket.h> (which is included from <bits/socket.h>)
>> provided ioctl operations for sockets.  User code accessed them
>> through <sys/socket.h>.  The kernel UAPI headers have removed these
>> definitions in favor of <linux/sockios.h>.  This commit makes them
>> available via <sys/socket.h> again.
> 
> Looks good to me.
> 
> I wonder if we should still do these two changes in the kernel:
> 
> - include asm/socket.h from linux/socket.h for consistency
> - move the defines that got moved from asm/sockios.h to linux/sockios.h
>   back to the previous location to help anyone who is user
>   newer kernel headers with older glibc headers.

does user code actually expect these in sys/socket.h
or in asm/socket.h ?

man 7 socket
mentions SIOCGSTAMP but does not say the header.

man 2 ioctl_list
specifies include/asm-i386/socket.h as the location.

if user code tends to directly include asm/socket.h
then i think it's better to undo the kernel header
change than to put things in sys/socket.h.

(note: in musl these ioctl macros are in sys/ioctl.h
which is not a posix header so namespace rules are
less strict than for sys/socket.h and users tend to
include it for ioctl())