/* *  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/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>#include <linux/ipc_namespace.h> static struct kmem_cache *nsproxy_cachep; struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); static inline struct nsproxy *create_nsproxy(void){	struct nsproxy *nsproxy; 	nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);	if (nsproxy)		atomic_set(&nsproxy->count, 1);	return nsproxy;} /* * 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 = create_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->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->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_NEWPID | CLONE_NEWNET)))		return 0; 	if (!capable(CAP_SYS_ADMIN)) {		err = -EPERM;		goto out;	} 	/*	 * CLONE_NEWIPC must detach from the undolist: after switching	 * to a new ipc namespace, the semaphore arrays from the old	 * namespace are unreachable.  In clone parlance, CLONE_SYSVSEM	 * means share undolist with parent, so we must forbid using	 * it along with CLONE_NEWIPC.	 */	if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) {		err = -EINVAL;		goto out;	} 	new_ns = create_new_namespaces(flags, tsk, tsk->fs);	if (IS_ERR(new_ns)) {		err = PTR_ERR(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);	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_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, task_pid(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);