On Mon, Sep 15, 2014 at 05:36:16PM +0200, Michal Privoznik wrote:
On 15.09.2014 17:32, Martin Kletzander wrote: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 redhat com> >>--- >>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 We took the patch specifically to help Debian where the kernel has it but glibc is outdated.Either Debian should patch their glibc or we should at lease use SYS_setns IMHO.That's not gonna fly either. On my system, the SYS_setns is declared in: # grep -r SYS_setns /usr/include/ /usr/include/bits/syscall.h:#define SYS_setns __NR_setns And the syscall.h belongs to glibc, not kernel headers. So we are back at the start.
Well, I'd argue that we're not :) Distros could make our lives easier by not requiring us to guess their kernel's syscall numbers :)
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