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1651e14e28
This moves the mount namespace into the nsproxy. The mount namespace count now refers to the number of nsproxies point to it, rather than the number of tasks. As a result, the unshare_namespace() function in kernel/fork.c no longer checks whether it is being shared. Signed-off-by: Serge Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Andrey Savochkin <saw@sw.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
110 lines
2.1 KiB
C
110 lines
2.1 KiB
C
/*
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* Copyright (C) 2006 IBM Corporation
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*
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* Author: Serge Hallyn <serue@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/module.h>
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#include <linux/version.h>
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#include <linux/nsproxy.h>
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#include <linux/init_task.h>
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#include <linux/namespace.h>
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struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
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static inline void get_nsproxy(struct nsproxy *ns)
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{
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atomic_inc(&ns->count);
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}
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void get_task_namespaces(struct task_struct *tsk)
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{
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struct nsproxy *ns = tsk->nsproxy;
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if (ns) {
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get_nsproxy(ns);
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}
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}
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/*
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* creates a copy of "orig" with refcount 1.
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* This does not grab references to the contained namespaces,
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* so that needs to be done by dup_namespaces.
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*/
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static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
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{
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struct nsproxy *ns;
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ns = kmalloc(sizeof(struct nsproxy), GFP_KERNEL);
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if (ns) {
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memcpy(ns, orig, sizeof(struct nsproxy));
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atomic_set(&ns->count, 1);
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}
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return ns;
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}
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/*
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* copies the nsproxy, setting refcount to 1, and grabbing a
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* reference to all contained namespaces. Called from
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* sys_unshare()
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*/
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struct nsproxy *dup_namespaces(struct nsproxy *orig)
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{
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struct nsproxy *ns = clone_namespaces(orig);
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if (ns) {
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if (ns->namespace)
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get_namespace(ns->namespace);
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}
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return ns;
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}
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/*
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* called from clone. This now handles copy for nsproxy and all
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* namespaces therein.
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*/
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int copy_namespaces(int flags, struct task_struct *tsk)
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{
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struct nsproxy *old_ns = tsk->nsproxy;
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struct nsproxy *new_ns;
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int err = 0;
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if (!old_ns)
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return 0;
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get_nsproxy(old_ns);
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if (!(flags & CLONE_NEWNS))
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return 0;
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new_ns = clone_namespaces(old_ns);
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if (!new_ns) {
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err = -ENOMEM;
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goto out;
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}
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tsk->nsproxy = new_ns;
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err = copy_namespace(flags, tsk);
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if (err) {
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tsk->nsproxy = old_ns;
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put_nsproxy(new_ns);
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goto out;
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}
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out:
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put_nsproxy(old_ns);
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return err;
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}
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void free_nsproxy(struct nsproxy *ns)
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{
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if (ns->namespace)
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put_namespace(ns->namespace);
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kfree(ns);
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}
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