[libvirt] [PATCH] lxc: ensure setns() syscall is defined

Older versions of glibc don't provide the setns() syscall function wrapper, so we must define it ourselves to prevent build failure on old distros. Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; Pushed as a RHEL-6 build-break fix --- src/lxc/lxc_container.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index 8011ed0..feb8fad 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -95,6 +95,40 @@ VIR_LOG_INIT("lxc.lxc_container"); # define CLONE_NEWNET 0x40000000 /* New network namespace */ #endif +/* + * Workaround older glibc. While kernel may support the setns + * syscall, the glibc wrapper might not exist. If that's the + * case, use our own. + */ +#ifndef __NR_setns +# if defined(__x86_64__) +# define __NR_setns 308 +# elif defined(__i386__) +# define __NR_setns 346 +# elif defined(__arm__) +# define __NR_setns 375 +# elif defined(__aarch64__) +# define __NR_setns 375 +# elif defined(__powerpc__) +# define __NR_setns 350 +# elif defined(__s390__) +# define __NR_setns 339 +# endif +#endif + +#ifndef HAVE_SETNS +# if defined(__NR_setns) +# include <sys/syscall.h> + +static inline int setns(int fd, int nstype) +{ + return syscall(__NR_setns, fd, nstype); +} +# else /* !__NR_setns */ +# error Please determine the syscall number for setns on your architecture +# endif +#endif + /* messages between parent and container */ typedef char lxc_message_t; #define LXC_CONTINUE_MSG 'c' -- 2.4.3