Re: xattr.h wonkiness
On Thu, Mar 6, 2014 at 6:06 PM, Serge Hallyn <serge.hallyn@ubuntu.com> wrote:
> Quoting Carlos O'Donell (carlos@systemhalted.org):
>> On Fri, Feb 21, 2014 at 6:42 PM, Serge Hallyn <serge.hallyn@ubuntu.com> wrote:
>> > Hi, would a simple patchl ike this to misc/sys/xattr.h be
>> > acceptable? This showed up in a failure to build (of at least
>> > qemu, and aiui lots of other pkgs) after merging a new libcap2
>> > where sys/capability.h #included linux/xattr.h. It's being
>> > worked around by patching libcap2 to #include sys/xattr.h
>> > first, but presumably this will cause other breakages.
>>
>> Please follow the accepted practice for fixing coordination between
>> userspace and Linux kernel headers.
>>
>> Upstream glibc and the Linux kernel have already worked out a
>> mechanical solution to this problem, and we need people to work out
>> the patches and post them upstream.
>>
>> The solution is to coordinate the conflicting headers following this template:
>> https://sourceware.org/glibc/wiki/Synchronizing_Headers
>
> Thanks for the information. I tested the two patches at
> http://people.canonical.com/~serge/xattr-kernel-libc-fix/ and they
> seem to do the right thing. I'll send them out if they look ok.
Let me warn you that the glibc patch won't get accepted as-is.
You are adding a #ifdef for a Linux-specific define in OS-agnostic code.
Look at: https://sourceware.org/ml/libc-alpha/2013-08/msg00209.html
See how we adjust a Linux-specific header to define an OS-agnostic
variable to use in the OS-agnostic code e.g. __USE_FOO.
Cheers,
Carlos.
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