Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2004 IBM Corporation |
| 3 | * |
| 4 | * Author: Serge Hallyn <serue@us.ibm.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License as |
| 8 | * published by the Free Software Foundation, version 2 of the |
| 9 | * License. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/uts.h> |
| 14 | #include <linux/utsname.h> |
| 15 | #include <linux/version.h> |
| 16 | |
| 17 | /* |
Serge E. Hallyn | 071df10 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 18 | * Clone a new ns copying an original utsname, setting refcount to 1 |
| 19 | * @old_ns: namespace to clone |
| 20 | * Return NULL on error (failure to kmalloc), new ns otherwise |
| 21 | */ |
| 22 | static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns) |
| 23 | { |
| 24 | struct uts_namespace *ns; |
| 25 | |
| 26 | ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL); |
| 27 | if (ns) { |
| 28 | memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); |
| 29 | kref_init(&ns->kref); |
| 30 | } |
| 31 | return ns; |
| 32 | } |
| 33 | |
| 34 | /* |
| 35 | * unshare the current process' utsname namespace. |
| 36 | * called only in sys_unshare() |
| 37 | */ |
| 38 | int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts) |
| 39 | { |
| 40 | if (unshare_flags & CLONE_NEWUTS) { |
| 41 | if (!capable(CAP_SYS_ADMIN)) |
| 42 | return -EPERM; |
| 43 | |
| 44 | *new_uts = clone_uts_ns(current->nsproxy->uts_ns); |
| 45 | if (!*new_uts) |
| 46 | return -ENOMEM; |
| 47 | } |
| 48 | |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | /* |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 53 | * Copy task tsk's utsname namespace, or clone it if flags |
| 54 | * specifies CLONE_NEWUTS. In latter case, changes to the |
| 55 | * utsname of this process won't be seen by parent, and vice |
| 56 | * versa. |
| 57 | */ |
| 58 | int copy_utsname(int flags, struct task_struct *tsk) |
| 59 | { |
| 60 | struct uts_namespace *old_ns = tsk->nsproxy->uts_ns; |
Serge E. Hallyn | 071df10 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 61 | struct uts_namespace *new_ns; |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 62 | int err = 0; |
| 63 | |
| 64 | if (!old_ns) |
| 65 | return 0; |
| 66 | |
| 67 | get_uts_ns(old_ns); |
| 68 | |
Serge E. Hallyn | 071df10 | 2006-10-02 02:18:17 -0700 | [diff] [blame] | 69 | if (!(flags & CLONE_NEWUTS)) |
| 70 | return 0; |
| 71 | |
| 72 | if (!capable(CAP_SYS_ADMIN)) { |
| 73 | err = -EPERM; |
| 74 | goto out; |
| 75 | } |
| 76 | |
| 77 | new_ns = clone_uts_ns(old_ns); |
| 78 | if (!new_ns) { |
| 79 | err = -ENOMEM; |
| 80 | goto out; |
| 81 | } |
| 82 | tsk->nsproxy->uts_ns = new_ns; |
| 83 | |
| 84 | out: |
| 85 | put_uts_ns(old_ns); |
Serge E. Hallyn | 4865ecf | 2006-10-02 02:18:14 -0700 | [diff] [blame] | 86 | return err; |
| 87 | } |
| 88 | |
| 89 | void free_uts_ns(struct kref *kref) |
| 90 | { |
| 91 | struct uts_namespace *ns; |
| 92 | |
| 93 | ns = container_of(kref, struct uts_namespace, kref); |
| 94 | kfree(ns); |
| 95 | } |