sysctl: add the kernel.ns_last_pid control
authorPavel Emelyanov <xemul@parallels.com>
Fri, 13 Jan 2012 01:20:27 +0000 (17:20 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 13 Jan 2012 04:13:11 +0000 (20:13 -0800)
commitb8f566b04d3cddd192cfd2418ae6d54ac6353792
tree32a5bf86548cd43feff4822d800b6a99e157b5d7
parentf5138e42211d4e8bfbd6ac5b3816348da1533433
sysctl: add the kernel.ns_last_pid control

The sysctl works on the current task's pid namespace, getting and setting
its last_pid field.

Writing is allowed for CAP_SYS_ADMIN-capable tasks thus making it possible
to create a task with desired pid value.  This ability is required badly
for the checkpoint/restore in userspace.

This approach suits all the parties for now.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation/sysctl/kernel.txt
kernel/pid.c
kernel/pid_namespace.c