Re: [libvirt] [PATCH] virprocess: Extend list of platforms for setns wrapper

On Mon, Sep 15, 2014 at 04:22:18PM +0100, Daniel P. Berrange wrote: > On Mon, Sep 15, 2014 at 05:20:46PM +0200, Michal Privoznik wrote: >> On 15.09.2014 17:15, Martin Kletzander wrote: >> >On Mon, Sep 15, 2014 at 03:43:55PM +0200, Michal Privoznik wrote: >> >>Currently, the setns() wrapper is supported only for x86_64 and i686 >> >>which leaves us failing to build on other platforms like arm, aarch64 >> >>and so on. This means, that the wrapper needs to be extended to those >> >>platforms and make to fail on runtime not compile time. >> >> >> >>The syscall numbers for other platforms was fetched using this >> >>command: >> >> >> >>kernel.git $ git grep "define.*__NR_setns" | grep -e arm -e powerpc -e >> >>s390 >> >>arch/arm/include/uapi/asm/unistd.h:#define >> >>__NR_setns (__NR_SYSCALL_BASE+375) >> >>arch/arm64/include/asm/unistd32.h:#define __NR_setns 375 >> >>arch/powerpc/include/uapi/asm/unistd.h:#define >> >>__NR_setns 350 >> >>arch/s390/include/uapi/asm/unistd.h:#define __NR_setns 339 >> >> >> >>Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; >> >>--- >> >>src/util/virprocess.c | 18 ++++++++++++------ >> >>1 file changed, 12 insertions(+), 6 deletions(-) >> >> >> > >> >NACK, we shouldn't be duplicating syscall definitions. There should >> >be AC_CHECK_FUNCS([setns]) (instead of AC_CHECK_FUNCS_ONCE() for the >> >syscall) and having with_lxc = "yes" and ac_cv_func_setns != "yes" >> >should result in an error. >> >> The only problem with this might be that on systems with older glibc >> (and >> there is plenty of them) libvirt will fail to build / miss this >> feature. And >> it's not that the kernel doesn't support the namesapces. But let me >> see if I >> can get some ACKs on that approach you're suggesting. > > That's basically what the code did before we added the #define or > NR_setns. > We took the patch specifically to help Debian where the kernel has it but > glibc is outdated. > Either Debian should patch their glibc or we should at lease use SYS_setns IMHO.