/* *  Copyright (C) 2004 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. */ #include <linux/module.h>#include <linux/uts.h>#include <linux/utsname.h>#include <linux/version.h> /* * Clone a new ns copying an original utsname, setting refcount to 1 * @old_ns: namespace to clone * Return NULL on error (failure to kmalloc), new ns otherwise */static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns){	struct uts_namespace *ns; 	ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);	if (ns) {		memcpy(&ns->name, &old_ns->name, sizeof(ns->name));		kref_init(&ns->kref);	}	return ns;} /* * unshare the current process' utsname namespace. * called only in sys_unshare() */int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts){	if (unshare_flags & CLONE_NEWUTS) {		if (!capable(CAP_SYS_ADMIN))			return -EPERM; 		*new_uts = clone_uts_ns(current->nsproxy->uts_ns);		if (!*new_uts)			return -ENOMEM;	} 	return 0;} /* * Copy task tsk's utsname namespace, or clone it if flags * specifies CLONE_NEWUTS.  In latter case, changes to the * utsname of this process won't be seen by parent, and vice * versa. */int copy_utsname(int flags, struct task_struct *tsk){	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;	struct uts_namespace *new_ns;	int err = 0; 	if (!old_ns)		return 0; 	get_uts_ns(old_ns); 	if (!(flags & CLONE_NEWUTS))		return 0; 	if (!capable(CAP_SYS_ADMIN)) {		err = -EPERM;		goto out;	} 	new_ns = clone_uts_ns(old_ns);	if (!new_ns) {		err = -ENOMEM;		goto out;	}	tsk->nsproxy->uts_ns = new_ns; out:	put_uts_ns(old_ns);	return err;} void free_uts_ns(struct kref *kref){	struct uts_namespace *ns; 	ns = container_of(kref, struct uts_namespace, kref);	kfree(ns);}