Re: [PATCH] y2038: fix socket.h header inclusion

[Arnd Bergmann]

On Thu, Mar 14, 2019 at 7:41 PM Florian Weimer <fw@xxxxxxxxxxxxx> wrote:
>
> * Arnd Bergmann:
>
> > diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
> > index 0d0fddb7e738..976e89b116e5 100644
> > --- a/arch/alpha/include/uapi/asm/socket.h
> > +++ b/arch/alpha/include/uapi/asm/socket.h
> > @@ -2,8 +2,8 @@
> >  #ifndef _UAPI_ASM_SOCKET_H
> >  #define _UAPI_ASM_SOCKET_H
> >
> > +#include <linux/posix_types.h>
> >  #include <asm/sockios.h>
> > -#include <asm/bitsperlong.h>
>
> This breaks POSIX conformance in glibc because the
> <linux/posix_types.h> header is not namespace clean.  It contains the
> identifiers fds_bits and val:
>
>         unsigned long fds_bits[__FD_SETSIZE / (8 * sizeof(long))];
>
>         int     val[2];

What is problematic about the struct members here? I had thought that
only the struct names have to be in a namespace to be usable here,
but not the members.

The only part that might be problematic is

#undef __FD_SETSIZE
#define __FD_SETSIZE    1024

but we already get that from a number of other inclusions of
linux/posix_types.h. Is this what you mean?

> We could duplicate some of the SO_* constants for POSIX mode in glibc,
> but it would be nice to avoid that.
>
> Is there a different way of fixing this on the kernel side that avoids
> including <linux/posix_types.h>?

We could use asm/posix_types.h instead of linux/posix_types.h,
would that address your concern?

       Arnd