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4865ecf1 SH |
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 | ||
071df104 SH |
17 | /* |
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 | ||
4865ecf1 SH |
34 | /* |
35 | * Copy task tsk's utsname namespace, or clone it if flags | |
36 | * specifies CLONE_NEWUTS. In latter case, changes to the | |
37 | * utsname of this process won't be seen by parent, and vice | |
38 | * versa. | |
39 | */ | |
e3222c4e | 40 | struct uts_namespace *copy_utsname(int flags, struct uts_namespace *old_ns) |
4865ecf1 | 41 | { |
071df104 | 42 | struct uts_namespace *new_ns; |
4865ecf1 | 43 | |
e3222c4e | 44 | BUG_ON(!old_ns); |
4865ecf1 SH |
45 | get_uts_ns(old_ns); |
46 | ||
071df104 | 47 | if (!(flags & CLONE_NEWUTS)) |
e3222c4e | 48 | return old_ns; |
071df104 SH |
49 | |
50 | new_ns = clone_uts_ns(old_ns); | |
071df104 | 51 | |
071df104 | 52 | put_uts_ns(old_ns); |
e3222c4e | 53 | return new_ns; |
4865ecf1 SH |
54 | } |
55 | ||
56 | void free_uts_ns(struct kref *kref) | |
57 | { | |
58 | struct uts_namespace *ns; | |
59 | ||
60 | ns = container_of(kref, struct uts_namespace, kref); | |
61 | kfree(ns); | |
62 | } |