From: Kirill Tkhai <[email protected]> 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 <[email protected]> Reviewed-by: Cyrill Gorcunov <[email protected]> Acked-by: Andrei Vagin <[email protected]> Cc: Andreas Gruenbacher <[email protected]> Cc: Kees Cook <[email protected]> Cc: Michael Kerrisk <[email protected]> Cc: Al Viro <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Paul Moore <[email protected]> Cc: Eric Biederman <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Serge Hallyn <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> (cherry picked from VZ8 commit 25b14e92af1a563c7331466ca59188f88050bbf0) https://jira.sw.ru/browse/PSBM-102357 Signed-off-by: Pavel Tikhomirov <[email protected]> --- fs/nsfs.c | 4 +++- include/linux/proc_ns.h | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/nsfs.c b/fs/nsfs.c index fb5215552a8d..ade35cf01d0a 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -190,9 +190,11 @@ 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; diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h index a8645c5eb679..ea002b8e5ab9 100644 --- a/include/linux/proc_ns.h +++ b/include/linux/proc_ns.h @@ -14,6 +14,7 @@ struct path; struct proc_ns_operations { const char *name; + const char *real_ns_name; int type; struct ns_common *(*get)(struct task_struct *task); void (*put)(struct ns_common *ns); -- 2.24.1 _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
