Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  Copyright (C) 2006 IBM Corporation

 *

 *  Author: Serge Hallyn <serue@us.ibm.com>

 *

 *  This program is free software; you can redistribute it and/or

 *  modify it under the terms of the GNU General Public License as

 *  published by the Free Software Foundation, version 2 of the

 *  License.

 *

 *  Jun 2006 - namespaces support

 *             OpenVZ, SWsoft Inc.

 *             Pavel Emelianov <xemul@openvz.org>

 */

#include <linux/module.h>

#include <linux/version.h>

#include <linux/nsproxy.h>

#include <linux/init_task.h>

#include <linux/mnt_namespace.h>

#include <linux/utsname.h>

#include <linux/pid_namespace.h>

#include <net/net_namespace.h>

static struct kmem_cache *nsproxy_cachep;

struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);

/*

 * creates a copy of "orig" with refcount 1.

 */

static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)

{

        struct nsproxy *ns;

        ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);

        if (ns) {

                memcpy(ns, orig, sizeof(struct nsproxy));

                atomic_set(&ns->count, 1);

        }

        return ns;

}

/*

 * Create new nsproxy and all of its the associated namespaces.

 * Return the newly created nsproxy.  Do not attach this to the task,

 * leave it to the caller to do proper locking and attach it to task.

 */

static struct nsproxy *create_new_namespaces(unsigned long flags,

                        struct task_struct *tsk, struct fs_struct *new_fs)

{

        struct nsproxy *new_nsp;

        int err;

        new_nsp = clone_nsproxy(tsk->nsproxy);

        if (!new_nsp)

                return ERR_PTR(-ENOMEM);

        new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);

        if (IS_ERR(new_nsp->mnt_ns)) {

                err = PTR_ERR(new_nsp->mnt_ns);

                goto out_ns;

        }

        new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);

        if (IS_ERR(new_nsp->uts_ns)) {

                err = PTR_ERR(new_nsp->uts_ns);

                goto out_uts;

        }

        new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);

        if (IS_ERR(new_nsp->ipc_ns)) {

                err = PTR_ERR(new_nsp->ipc_ns);

                goto out_ipc;

        }

        new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));

        if (IS_ERR(new_nsp->pid_ns)) {

                err = PTR_ERR(new_nsp->pid_ns);

                goto out_pid;

        }

        new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);

        if (IS_ERR(new_nsp->user_ns)) {

                err = PTR_ERR(new_nsp->user_ns);

                goto out_user;

        }

        new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns);

        if (IS_ERR(new_nsp->net_ns)) {

                err = PTR_ERR(new_nsp->net_ns);

                goto out_net;

        }

        return new_nsp;

out_net:

        if (new_nsp->user_ns)

                put_user_ns(new_nsp->user_ns);

out_user:

        if (new_nsp->pid_ns)

                put_pid_ns(new_nsp->pid_ns);

out_pid:

        if (new_nsp->ipc_ns)

                put_ipc_ns(new_nsp->ipc_ns);

out_ipc:

        if (new_nsp->uts_ns)

                put_uts_ns(new_nsp->uts_ns);

out_uts:

        if (new_nsp->mnt_ns)

                put_mnt_ns(new_nsp->mnt_ns);

out_ns:

        kmem_cache_free(nsproxy_cachep, new_nsp);

        return ERR_PTR(err);

}

/*

 * called from clone.  This now handles copy for nsproxy and all

 * namespaces therein.

 */

int copy_namespaces(unsigned long flags, struct task_struct *tsk)

{

        struct nsproxy *old_ns = tsk->nsproxy;

        struct nsproxy *new_ns;

        int err = 0;

        if (!old_ns)

                return 0;

        get_nsproxy(old_ns);

        if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |

                                CLONE_NEWUSER | CLONE_NEWPID | CLONE_NEWNET)))

                return 0;

        if (!capable(CAP_SYS_ADMIN)) {

                err = -EPERM;

                goto out;

        }

        new_ns = create_new_namespaces(flags, tsk, tsk->fs);

        if (IS_ERR(new_ns)) {

                err = PTR_ERR(new_ns);

                goto out;

        }

        err = ns_cgroup_clone(tsk);

        if (err) {

                put_nsproxy(new_ns);

                goto out;

        }

        tsk->nsproxy = new_ns;

out:

        put_nsproxy(old_ns);

        return err;

}

void free_nsproxy(struct nsproxy *ns)

{

        if (ns->mnt_ns)

                put_mnt_ns(ns->mnt_ns);

        if (ns->uts_ns)

                put_uts_ns(ns->uts_ns);

        if (ns->ipc_ns)

                put_ipc_ns(ns->ipc_ns);

        if (ns->pid_ns)

                put_pid_ns(ns->pid_ns);

        if (ns->user_ns)

                put_user_ns(ns->user_ns);

        put_net(ns->net_ns);

        kmem_cache_free(nsproxy_cachep, ns);

}

/*

 * Called from unshare. Unshare all the namespaces part of nsproxy.

 * On success, returns the new nsproxy.

 */

int unshare_nsproxy_namespaces(unsigned long unshare_flags,

                struct nsproxy **new_nsp, struct fs_struct *new_fs)

{

        int err = 0;

        if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |

                               CLONE_NEWUSER | CLONE_NEWNET)))

                return 0;

        if (!capable(CAP_SYS_ADMIN))

                return -EPERM;

        *new_nsp = create_new_namespaces(unshare_flags, current,

                                new_fs ? new_fs : current->fs);

        if (IS_ERR(*new_nsp)) {

                err = PTR_ERR(*new_nsp);

                goto out;

        }

        err = ns_cgroup_clone(current);

        if (err)

                put_nsproxy(*new_nsp);

out:

        return err;

}

void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)

{

        struct nsproxy *ns;

        might_sleep();

        ns = p->nsproxy;

        rcu_assign_pointer(p->nsproxy, new);

        if (ns && atomic_dec_and_test(&ns->count)) {

                /*

                 * wait for others to get what they want from this nsproxy.

                 *

                 * cannot release this nsproxy via the call_rcu() since

                 * put_mnt_ns() will want to sleep

                 */

                synchronize_rcu();

                free_nsproxy(ns);

        }

}

void exit_task_namespaces(struct task_struct *p)

{

        switch_task_namespaces(p, NULL);

}

static int __init nsproxy_cache_init(void)

{

        nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);

        return 0;

}

module_init(nsproxy_cache_init);