• Kirill Tkhai's avatar
    ns: allow ns_entries to have custom symlink content · 25b14e92
    Kirill Tkhai authored
    Patch series "Expose task pid_ns_for_children to userspace".
    pid_ns_for_children set by a task is known only to the task itself, and
    it's impossible to identify it from outside.
    It's a big problem for checkpoint/restore software like CRIU, because it
    can't correctly handle tasks, that do setns(CLONE_NEWPID) in proccess of
    their work.  If they have a custom pid_ns_for_children before dump, they
    must have the same ns after restore.  Otherwise, restored task bumped
    into enviroment it does not expect.
    This patchset solves the problem.  It exposes pid_ns_for_children to ns
    directory in standard way with the name "pid_for_children":
      ~# ls /proc/5531/ns -l | grep pid
      lrwxrwxrwx 1 root root 0 Jan 14 16:38 pid -> pid:[4026531836]
      lrwxrwxrwx 1 root root 0 Jan 14 16:38 pid_for_children -> pid:[4026532286]
    This patch (of 2):
    Make possible to have link content prefix yyy different from the link
    name xxx:
      $ readlink /proc/[pid]/ns/xxx
    This will be used in next patch.
    Link: http://lkml.kernel.org/r/149201120318.6007.7362655181033883000.stgit@localhost.localdomainSigned-off-by: default avatarKirill Tkhai <ktkhai@virtuozzo.com>
    Reviewed-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
    Acked-by: default avatarAndrei Vagin <avagin@virtuozzo.com>
    Cc: Andreas Gruenbacher <agruenba@redhat.com>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Oleg Nesterov <oleg@redhat.com>
    Cc: Paul Moore <paul@paul-moore.com>
    Cc: Eric Biederman <ebiederm@xmission.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Serge Hallyn <serge@hallyn.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
nsfs.c 5.63 KB