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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/err.h> |
16 | #include <linux/slab.h> |
17 | |
18 | static struct uts_namespace *create_uts_ns(void) |
19 | { |
20 | struct uts_namespace *uts_ns; |
21 | |
22 | uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL); |
23 | if (uts_ns) |
24 | kref_init(&uts_ns->kref); |
25 | return uts_ns; |
26 | } |
27 | |
28 | /* |
29 | * Clone a new ns copying an original utsname, setting refcount to 1 |
30 | * @old_ns: namespace to clone |
31 | * Return NULL on error (failure to kmalloc), new ns otherwise |
32 | */ |
33 | static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns) |
34 | { |
35 | struct uts_namespace *ns; |
36 | |
37 | ns = create_uts_ns(); |
38 | if (!ns) |
39 | return ERR_PTR(-ENOMEM); |
40 | |
41 | down_read(&uts_sem); |
42 | memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); |
43 | up_read(&uts_sem); |
44 | return ns; |
45 | } |
46 | |
47 | /* |
48 | * Copy task tsk's utsname namespace, or clone it if flags |
49 | * specifies CLONE_NEWUTS. In latter case, changes to the |
50 | * utsname of this process won't be seen by parent, and vice |
51 | * versa. |
52 | */ |
53 | struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns) |
54 | { |
55 | struct uts_namespace *new_ns; |
56 | |
57 | BUG_ON(!old_ns); |
58 | get_uts_ns(old_ns); |
59 | |
60 | if (!(flags & CLONE_NEWUTS)) |
61 | return old_ns; |
62 | |
63 | new_ns = clone_uts_ns(old_ns); |
64 | |
65 | put_uts_ns(old_ns); |
66 | return new_ns; |
67 | } |
68 | |
69 | void free_uts_ns(struct kref *kref) |
70 | { |
71 | struct uts_namespace *ns; |
72 | |
73 | ns = container_of(kref, struct uts_namespace, kref); |
74 | kfree(ns); |
75 | } |
76 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9