cae7a366f7
I happened to find the spinlock in struct ns_cgroup is never used. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
/*
|
|
* ns_cgroup.c - namespace cgroup subsystem
|
|
*
|
|
* Copyright 2006, 2007 IBM Corp
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/cgroup.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/nsproxy.h>
|
|
|
|
struct ns_cgroup {
|
|
struct cgroup_subsys_state css;
|
|
};
|
|
|
|
struct cgroup_subsys ns_subsys;
|
|
|
|
static inline struct ns_cgroup *cgroup_to_ns(
|
|
struct cgroup *cgroup)
|
|
{
|
|
return container_of(cgroup_subsys_state(cgroup, ns_subsys_id),
|
|
struct ns_cgroup, css);
|
|
}
|
|
|
|
int ns_cgroup_clone(struct task_struct *task, struct pid *pid)
|
|
{
|
|
char name[PROC_NUMBUF];
|
|
|
|
snprintf(name, PROC_NUMBUF, "%d", pid_vnr(pid));
|
|
return cgroup_clone(task, &ns_subsys, name);
|
|
}
|
|
|
|
/*
|
|
* Rules:
|
|
* 1. you can only enter a cgroup which is a child of your current
|
|
* cgroup
|
|
* 2. you can only place another process into a cgroup if
|
|
* a. you have CAP_SYS_ADMIN
|
|
* b. your cgroup is an ancestor of task's destination cgroup
|
|
* (hence either you are in the same cgroup as task, or in an
|
|
* ancestor cgroup thereof)
|
|
*/
|
|
static int ns_can_attach(struct cgroup_subsys *ss,
|
|
struct cgroup *new_cgroup, struct task_struct *task)
|
|
{
|
|
struct cgroup *orig;
|
|
|
|
if (current != task) {
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
if (!cgroup_is_descendant(new_cgroup))
|
|
return -EPERM;
|
|
}
|
|
|
|
if (atomic_read(&new_cgroup->count) != 0)
|
|
return -EPERM;
|
|
|
|
orig = task_cgroup(task, ns_subsys_id);
|
|
if (orig && orig != new_cgroup->parent)
|
|
return -EPERM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Rules: you can only create a cgroup if
|
|
* 1. you are capable(CAP_SYS_ADMIN)
|
|
* 2. the target cgroup is a descendant of your own cgroup
|
|
*/
|
|
static struct cgroup_subsys_state *ns_create(struct cgroup_subsys *ss,
|
|
struct cgroup *cgroup)
|
|
{
|
|
struct ns_cgroup *ns_cgroup;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return ERR_PTR(-EPERM);
|
|
if (!cgroup_is_descendant(cgroup))
|
|
return ERR_PTR(-EPERM);
|
|
|
|
ns_cgroup = kzalloc(sizeof(*ns_cgroup), GFP_KERNEL);
|
|
if (!ns_cgroup)
|
|
return ERR_PTR(-ENOMEM);
|
|
return &ns_cgroup->css;
|
|
}
|
|
|
|
static void ns_destroy(struct cgroup_subsys *ss,
|
|
struct cgroup *cgroup)
|
|
{
|
|
struct ns_cgroup *ns_cgroup;
|
|
|
|
ns_cgroup = cgroup_to_ns(cgroup);
|
|
kfree(ns_cgroup);
|
|
}
|
|
|
|
struct cgroup_subsys ns_subsys = {
|
|
.name = "ns",
|
|
.can_attach = ns_can_attach,
|
|
.create = ns_create,
|
|
.destroy = ns_destroy,
|
|
.subsys_id = ns_subsys_id,
|
|
};
|