[PATCH] virprocess: Drop workaround for setns() wrt old glibc

[Daniel P. Berrangé]

On Tue, May 24, 2022 at 01:40:54PM +0200, Michal Privoznik wrote:
> We have our own implementation of setns() which was introduced in
> v1.2.9-rc1~190 and extended afterwards. The reason was that back
> in 2014 we were dealing with glibc that in some of its older
> versions did not provide the function. Mostly for non-intel
> arches. Nevertheless, glibc now offers the function for all
> architectures we care about (aarch64 being the freshest
> architecture where the function was introduced, in glibc-2.17).
> 
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
>  src/util/virprocess.c | 55 +++++++++----------------------------------
>  1 file changed, 11 insertions(+), 44 deletions(-)
> 
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index 36d7df050a..f0a79396e7 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -27,7 +27,6 @@
>  #ifndef WIN32
>  # include <sys/wait.h>
>  #endif
> -#include <unistd.h>
>  #if WITH_SYS_MOUNT_H
>  # include <sys/mount.h>
>  #endif
> @@ -70,49 +69,6 @@
>  
>  VIR_LOG_INIT("util.process");
>  
> -#ifdef __linux__
> -/*
> - * 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 WITH_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
> -#else /* !__linux__ */
> -static inline int setns(int fd G_GNUC_UNUSED, int nstype G_GNUC_UNUSED)
> -{
> -    virReportSystemError(ENOSYS, "%s",
> -                         _("Namespaces are not supported on this platform."));
> -    return -1;
> -}
> -#endif
> -
>  VIR_ENUM_IMPL(virProcessSchedPolicy,
>                VIR_PROC_POLICY_LAST,
>                "none",
> @@ -714,6 +670,7 @@ int virProcessGetNamespaces(pid_t pid,
>  }
>  
>  
> +#if WITH_SETNS

We could assume  __linux__ at this point and remove the meson
check too for a slight speedup.

>  int virProcessSetNamespaces(size_t nfdlist,
>                              int *fdlist)
>  {
> @@ -742,6 +699,16 @@ int virProcessSetNamespaces(size_t nfdlist,
>      }
>      return 0;
>  }
> +#else
> +int virProcessSetNamespaces(size_t nfdlist G_GNUC_UNUSED,
> +                            int *fdlist G_GNUC_UNUSED)
> +{
> +    virReportSystemError(ENOSYS, "%s",
> +                         _("Namespaces are not supported on this platform."));
> +    return -1;
> +}
> +#endif
> +
>  
>  #if WITH_PRLIMIT
>  static int
> -- 
> 2.35.1
> 

With regards,
Daniel
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