| /* |
| * 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/export.h> |
| #include <linux/uts.h> |
| #include <linux/utsname.h> |
| #include <linux/err.h> |
| #include <linux/slab.h> |
| #include <linux/user_namespace.h> |
| #include <linux/proc_fs.h> |
| |
| static struct uts_namespace *create_uts_ns(void) |
| { |
| struct uts_namespace *uts_ns; |
| |
| uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL); |
| if (uts_ns) |
| kref_init(&uts_ns->kref); |
| return uts_ns; |
| } |
| |
| /* |
| * 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 task_struct *tsk, |
| struct uts_namespace *old_ns) |
| { |
| struct uts_namespace *ns; |
| |
| ns = create_uts_ns(); |
| if (!ns) |
| return ERR_PTR(-ENOMEM); |
| |
| down_read(&uts_sem); |
| memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); |
| ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns); |
| up_read(&uts_sem); |
| 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 task_struct *tsk) |
| { |
| struct uts_namespace *old_ns = tsk->nsproxy->uts_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(tsk, 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); |
| put_user_ns(ns->user_ns); |
| kfree(ns); |
| } |
| |
| static void *utsns_get(struct task_struct *task) |
| { |
| struct uts_namespace *ns = NULL; |
| struct nsproxy *nsproxy; |
| |
| rcu_read_lock(); |
| nsproxy = task_nsproxy(task); |
| if (nsproxy) { |
| ns = nsproxy->uts_ns; |
| get_uts_ns(ns); |
| } |
| rcu_read_unlock(); |
| |
| return ns; |
| } |
| |
| static void utsns_put(void *ns) |
| { |
| put_uts_ns(ns); |
| } |
| |
| static int utsns_install(struct nsproxy *nsproxy, void *ns) |
| { |
| get_uts_ns(ns); |
| put_uts_ns(nsproxy->uts_ns); |
| nsproxy->uts_ns = ns; |
| return 0; |
| } |
| |
| const struct proc_ns_operations utsns_operations = { |
| .name = "uts", |
| .type = CLONE_NEWUTS, |
| .get = utsns_get, |
| .put = utsns_put, |
| .install = utsns_install, |
| }; |
| |