/* * 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/err.h> #include <linux/slab.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) return ERR_PTR(-ENOMEM); down_read(&uts_sem); memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); up_read(&uts_sem); kref_init(&ns->kref); return ns; } /* * 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. */ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns) { struct uts_namespace *new_ns; BUG_ON(!old_ns); get_uts_ns(old_ns); if (!(flags & CLONE_NEWUTS)) return old_ns; new_ns = clone_uts_ns(old_ns); put_uts_ns(old_ns); return new_ns; } void free_uts_ns(struct kref *kref) { struct uts_namespace *ns; ns = container_of(kref, struct uts_namespace, kref); kfree(ns); }