Hi Huacai,
On Thu, Jul 12, 2018 at 07:09:04AM +0800, Huacai Chen wrote:
> >> It seems like some application use "uname" command's output to do
> >> something different between big-endian and little-endian, so we make
> >> UTS_MACHINE reflect both 32bit/64bit and big-endian/little-endian.
> >
> > Since UTS_MACHINE is exposed to userland (which is of course the point
> > of your patch) I'm not comfortable changing it. If some piece of code
> > checks whether uname -m gives "mips" then we'd break it by suddenly
> > giving "mipsel". This is too risky.
> >
> > Which applications are you talking about that look for endianness in
> > uname output? Since Linux on MIPS doesn't expose endianness information
> > in this way these applications will always have been broken on MIPS
> > systems, and it would make more sense to fix the applications than to
> > change the kernel & probably break others.
>
> Hi, we are making Fedora on MIPS, we found that yum use uname's output
> to adjust endianness compatibility. We haven't seen anything broken
> while we changing mips64 to mips64el, do you know something about
> "broken things with this changing". I also don't want to change
> UTS_MACHINE, but if it is harmless, I think we can just do it.
A quick GitHub code search find a ton of things which check uname -m,
some of which expect the exact string "mips":
https://github.com/search?l=&p=1&q=uname+-m+mips&type=Code
UTS_MACHINE is not something to change.
Can you just have yum detect endianness some other way? Wikipedia tells
me yum is written in python, and a quick Google tells me there's a
sys.byteorder variable which would indicate endianness. Can you just use
that?
Thanks,
Paul
