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Re: Redefinition of struct in6_addr in <netinet/in.h> and <linux/in6.h>
- From: "Carlos O'Donell" <carlos at systemhalted dot org>
- To: Mike Frysinger <vapier at gentoo dot org>
- Cc: David Miller <davem at davemloft dot net>, libc-alpha at sourceware dot org, bhutchings at solarflare dot com, yoshfuji at linux-ipv6 dot org, amwang at redhat dot com, tmb at mageia dot org, eblake at redhat dot com, netdev at vger dot kernel dot org, linux-kernel at vger dot kernel dot org, libvirt-list at redhat dot com, tgraf at suug dot ch, schwab at suse dot de
- Date: Thu, 17 Jan 2013 23:22:26 -0500
- Subject: Re: Redefinition of struct in6_addr in <netinet/in.h> and <linux/in6.h>
- References: <201301161205.04502.vapier@gentoo.org><50F75EA7.4060309@systemhalted.org><20130116.221538.1756411165313441486.davem@davemloft.net><201301172320.19905.vapier@gentoo.org>
On Thu, Jan 17, 2013 at 11:20 PM, Mike Frysinger <vapier@gentoo.org> wrote:
> On Wednesday 16 January 2013 22:15:38 David Miller wrote:
>> From: Carlos O'Donell <carlos@systemhalted.org>
>> Date: Wed, 16 Jan 2013 21:15:03 -0500
>>
>> > +/* If a glibc-based userspace has already included in.h, then we will
>> > not + * define in6_addr (nor the defines), sockaddr_in6, or ipv6_mreq.
>> > The + * ABI used by the kernel and by glibc match exactly. Neither the
>> > kernel + * nor glibc should break this ABI without coordination.
>> > + */
>> > +#ifndef _NETINET_IN_H
>> > +
>>
>> I think we should shoot for a non-glibc-centric solution.
>>
>> I can't imagine that other libc's won't have the same exact problem
>> with their netinet/in.h conflicting with the kernel's, redefining
>> structures like in6_addr, that we'd want to provide a protection
>> scheme for here as well.
>
> yes, the kernel's use of __GLIBC__ in exported headers has already caused
> problems in the past. fortunately, it's been reduced down to just one case
> now (stat.h). let's not balloon it back up.
> -mike
I also see coda.h has grown a __GLIBC__ usage.
In the next revision of the patch I created a single libc-compat.h header
which encompasses the logic for any libc that wants to coordinate with
the kernel headers.
It's simple enough to move all of the __GLIBC__ uses into libc-compat.h,
then you control userspace libc coordination from one file.
Cheers,
Carlos.