/* * 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/namespace.h> #include <linux/utsname.h> struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); static inline void get_nsproxy(struct nsproxy *ns) { atomic_inc(&ns->count); } void get_task_namespaces(struct task_struct *tsk) { struct nsproxy *ns = tsk->nsproxy; if (ns) { get_nsproxy(ns); } } /* * creates a copy of "orig" with refcount 1. * This does not grab references to the contained namespaces, * so that needs to be done by dup_namespaces. */ static inline struct nsproxy *clone_namespaces(struct nsproxy *orig) { struct nsproxy *ns; ns = kmalloc(sizeof(struct nsproxy), GFP_KERNEL); if (ns) { memcpy(ns, orig, sizeof(struct nsproxy)); atomic_set(&ns->count, 1); } return ns; } /* * copies the nsproxy, setting refcount to 1, and grabbing a * reference to all contained namespaces. Called from * sys_unshare() */ struct nsproxy *dup_namespaces(struct nsproxy *orig) { struct nsproxy *ns = clone_namespaces(orig); if (ns) { if (ns->namespace) get_namespace(ns->namespace); if (ns->uts_ns) get_uts_ns(ns->uts_ns); if (ns->ipc_ns) get_ipc_ns(ns->ipc_ns); } return ns; } /* * called from clone. This now handles copy for nsproxy and all * namespaces therein. */ int copy_namespaces(int 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))) return 0; new_ns = clone_namespaces(old_ns); if (!new_ns) { err = -ENOMEM; goto out; } tsk->nsproxy = new_ns; err = copy_namespace(flags, tsk); if (err) goto out_ns; err = copy_utsname(flags, tsk); if (err) goto out_uts; err = copy_ipcs(flags, tsk); if (err) goto out_ipc; out: put_nsproxy(old_ns); return err; out_ipc: if (new_ns->uts_ns) put_uts_ns(new_ns->uts_ns); out_uts: if (new_ns->namespace) put_namespace(new_ns->namespace); out_ns: tsk->nsproxy = old_ns; kfree(new_ns); goto out; } void free_nsproxy(struct nsproxy *ns) { if (ns->namespace) put_namespace(ns->namespace); if (ns->uts_ns) put_uts_ns(ns->uts_ns); if (ns->ipc_ns) put_ipc_ns(ns->ipc_ns); kfree(ns); }