Re: Possible issue around utime() and symlinks on at least MIPS64

["A. Wilcox" <awilfox@adelielinux.org>]

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On 04/18/18 15:00, Rich Felker wrote:
> On Thu, Jul 06, 2017 at 02:50:16PM +0100, Adam Hill wrote:
>> Hi,
>> 
>> Not carried out ANY investigation around this... unfortunately I
>> don't have any time atm. Could also have been mentioned already or
>> actually be a bug in tar itself etc. but I couldn't find anything
>> with my quick search. Just thought I'd mention it in case anyone
>> does feel inclined to investigate.
>> 
>> I compiled OpenWrt using pretty much default build settings for an
>> octeon chip... it uses musl-1.1.16. The only real change I made was
>> to use GNU tar rather than busybox. The resulting tar binary can't
>> fix the modification/access times on any extracted symbolic links,
>>  resulting in for example:
>> 
>> tar: usr/share/zoneinfo/Africa: Cannot utime: Invalid argument
>> 
>> I didn't have strace available so can't even be sure tar's using
>> utime()... just going by the error message alone.
>> 
>> I recompiled OpenWrt changing only the C library ( to GCC ) and the
>> resulting tar binary worked fine... so I can only *assume* it's
>> something to do with musl.
> 
> Did anyone ever get a chance to look further into this? It's been on 
> my todo for a long time, but without sufficient information to 
> reproduce I don't know where to begin. I spent about 20 minutes 
> looking at the musl and kernel code now and it does not seem likely 
> that this is mips64-specific.
> 
> Rich
> 

This really sounds like broken cross-compiling.  When we cross-compile
cp, it's unable to handle xattrs until it's re-compiled on native
hardware.  I'd suggest poking around at autoconf for GNU tar and seeing
what it is 'guessing' the environment is like, and perhaps overriding
some with ac_*={yes,no} on the configure line.

Best,
--arw

-- 
A. Wilcox (awilfox)
Project Lead, Adélie Linux
http://adelielinux.org


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