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authorKirill Tkhai <ktkhai@virtuozzo.com>2017-05-08 15:56:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-08 17:15:12 -0700
commit25b14e92af1a563c7331466ca59188f88050bbf0 (patch)
tree3bf6e81e06b3d9186a620b2ad7327193f0eb7b52 /fs/nsfs.c
parent8896c23d2ef803f1883fea73117a435925c2b4c4 (diff)
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ns: allow ns_entries to have custom symlink content
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 yyy:[4026531838] This will be used in next patch. Link: http://lkml.kernel.org/r/149201120318.6007.7362655181033883000.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Andrei 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/nsfs.c')
-rw-r--r--fs/nsfs.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/nsfs.c b/fs/nsfs.c
index 323f492e0822..f3db56e83dd2 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -196,9 +196,11 @@ int ns_get_name(char *buf, size_t size, struct task_struct *task,
{
struct ns_common *ns;
int res = -ENOENT;
+ const char *name;
ns = ns_ops->get(task);
if (ns) {
- res = snprintf(buf, size, "%s:[%u]", ns_ops->name, ns->inum);
+ name = ns_ops->real_ns_name ? : ns_ops->name;
+ res = snprintf(buf, size, "%s:[%u]", name, ns->inum);
ns_ops->put(ns);
}
return res;