jdk7-b64 has new dependency on glibc-2.4

[Alan Bateman]

Alan Bateman wrote:
> Martin Buchholz wrote:
>> Hi Alan,
>>
>> As of openjdk7-b64, one can no longer build or run on glibc 2.3 
>> systems because of a new dependency
>> on fdopendir (and perhaps other glibc 2.4 functions).
>>
>> ../../../src/solaris/native/sun/nio/fs/UnixNativeDispatcher.c: In 
>> function 'Java_sun_nio_fs_UnixNativeDispatcher_fdopendir':
>> ../../../src/solaris/native/sun/nio/fs/UnixNativeDispatcher.c:569: 
>> warning: implicit declaration of function 'fdopendir'
>>
>> I have been advocating continued support of glibc 2.3 systems,
>> but this does not seem to be a popular sentiment.
>>
>> Would the nio2 team (and Sun)
>> - regard the new build failure as a bug to be fixed?
>> - grudgingly accept patches to allow possibly reduced functionality 
>> on older systems?
>> - refuse such patches?
>>
>> Thanks,
>>
>> Martin
> Sorry for the late reply, I've been on vacation.
>
> I don't think I've seen any discussion about the oldest version of 
> glibc that OpenJDK should build with. As you know, in Sun, we build on 
> Fedora 9 now (glibc 2.8) so it's possible that dependencies on more 
> recent glibc releases might creep in, unintentionally, as in this case.
>
> I don't have any objection to locating fdopendir at runtime. That's 
> the way it used to work before b64 and an over-sight, on my part, that 
> this was only a recent addition to glibc. It's only used in the 
> optional SecureDirectoryStream support and so isn't required to be 
> present. The attached should get you going for now (you've probably 
> done this already). Before you push this or similar, I'd like to 
> re-examine the capability check to see this one should be lumped in 
> with the existing *at calls or be its own capability.
>
> -Alan.
Martin - someone pinged me to say the BSD folks had to apply a similar 
patch. As the implementation already works when fdopendir is not present 
then I propose we just revert this to what we had prior to b64. Here's 
the patch:
    http://cr.openjdk.java.net/~alanb/6864319/webrev.00/

Can you review? If we push it today then it will be in b68.

Thanks,
Alan.