target: simplify backend attribute implementation
[linux-2.6-block.git] / ipc / msgutil.c
CommitLineData
1da177e4 1/*
f30c2269 2 * linux/ipc/msgutil.c
1da177e4
LT
3 * Copyright (C) 1999, 2004 Manfred Spraul
4 *
5 * This file is released under GNU General Public Licence version 2 or
6 * (at your option) any later version.
7 *
8 * See the file COPYING for more details.
9 */
10
11#include <linux/spinlock.h>
12#include <linux/init.h>
13#include <linux/security.h>
14#include <linux/slab.h>
15#include <linux/ipc.h>
40401530 16#include <linux/msg.h>
614b84cf 17#include <linux/ipc_namespace.h>
40401530 18#include <linux/utsname.h>
0bb80f24 19#include <linux/proc_ns.h>
1e3c941c 20#include <linux/uaccess.h>
1da177e4
LT
21
22#include "util.h"
23
7eafd7c7
SH
24DEFINE_SPINLOCK(mq_lock);
25
614b84cf
SH
26/*
27 * The next 2 defines are here bc this is the only file
28 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
29 * and not CONFIG_IPC_NS.
30 */
31struct ipc_namespace init_ipc_ns = {
7eafd7c7 32 .count = ATOMIC_INIT(1),
b515498f 33 .user_ns = &init_user_ns,
435d5f4b 34 .ns.inum = PROC_IPC_INIT_INO,
33c42940
AV
35#ifdef CONFIG_IPC_NS
36 .ns.ops = &ipcns_operations,
37#endif
614b84cf
SH
38};
39
40atomic_t nr_ipc_ns = ATOMIC_INIT(1);
41
1da177e4 42struct msg_msgseg {
1e3c941c 43 struct msg_msgseg *next;
1da177e4
LT
44 /* the next part of the message follows immediately */
45};
46
4e9b45a1
MK
47#define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg))
48#define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg))
1da177e4 49
be5f4b33 50
4e9b45a1 51static struct msg_msg *alloc_msg(size_t len)
1da177e4
LT
52{
53 struct msg_msg *msg;
54 struct msg_msgseg **pseg;
4e9b45a1 55 size_t alen;
1da177e4 56
3d8fa456 57 alen = min(len, DATALEN_MSG);
5cbded58 58 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
1da177e4 59 if (msg == NULL)
be5f4b33 60 return NULL;
1da177e4
LT
61
62 msg->next = NULL;
63 msg->security = NULL;
64
be5f4b33
PH
65 len -= alen;
66 pseg = &msg->next;
67 while (len > 0) {
68 struct msg_msgseg *seg;
69 alen = min(len, DATALEN_SEG);
70 seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL);
71 if (seg == NULL)
72 goto out_err;
73 *pseg = seg;
74 seg->next = NULL;
75 pseg = &seg->next;
76 len -= alen;
77 }
78
79 return msg;
80
81out_err:
82 free_msg(msg);
83 return NULL;
84}
85
4e9b45a1 86struct msg_msg *load_msg(const void __user *src, size_t len)
be5f4b33
PH
87{
88 struct msg_msg *msg;
89 struct msg_msgseg *seg;
2b3097a2 90 int err = -EFAULT;
4e9b45a1 91 size_t alen;
be5f4b33
PH
92
93 msg = alloc_msg(len);
94 if (msg == NULL)
95 return ERR_PTR(-ENOMEM);
96
97 alen = min(len, DATALEN_MSG);
2b3097a2 98 if (copy_from_user(msg + 1, src, alen))
1da177e4 99 goto out_err;
1da177e4 100
da085d45
PH
101 for (seg = msg->next; seg != NULL; seg = seg->next) {
102 len -= alen;
103 src = (char __user *)src + alen;
3d8fa456 104 alen = min(len, DATALEN_SEG);
2b3097a2 105 if (copy_from_user(seg + 1, src, alen))
1da177e4 106 goto out_err;
1da177e4
LT
107 }
108
109 err = security_msg_msg_alloc(msg);
110 if (err)
111 goto out_err;
112
113 return msg;
114
115out_err:
116 free_msg(msg);
117 return ERR_PTR(err);
118}
4a674f34
SK
119#ifdef CONFIG_CHECKPOINT_RESTORE
120struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
121{
122 struct msg_msgseg *dst_pseg, *src_pseg;
4e9b45a1
MK
123 size_t len = src->m_ts;
124 size_t alen;
4a674f34
SK
125
126 BUG_ON(dst == NULL);
127 if (src->m_ts > dst->m_ts)
128 return ERR_PTR(-EINVAL);
129
3d8fa456 130 alen = min(len, DATALEN_MSG);
4a674f34
SK
131 memcpy(dst + 1, src + 1, alen);
132
da085d45
PH
133 for (dst_pseg = dst->next, src_pseg = src->next;
134 src_pseg != NULL;
135 dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) {
136
137 len -= alen;
3d8fa456 138 alen = min(len, DATALEN_SEG);
4a674f34 139 memcpy(dst_pseg + 1, src_pseg + 1, alen);
4a674f34
SK
140 }
141
142 dst->m_type = src->m_type;
143 dst->m_ts = src->m_ts;
144
145 return dst;
146}
51eeacaa
SK
147#else
148struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
149{
150 return ERR_PTR(-ENOSYS);
151}
4a674f34 152#endif
4e9b45a1 153int store_msg(void __user *dest, struct msg_msg *msg, size_t len)
1da177e4 154{
4e9b45a1 155 size_t alen;
1da177e4
LT
156 struct msg_msgseg *seg;
157
3d8fa456 158 alen = min(len, DATALEN_MSG);
1da177e4
LT
159 if (copy_to_user(dest, msg + 1, alen))
160 return -1;
161
da085d45
PH
162 for (seg = msg->next; seg != NULL; seg = seg->next) {
163 len -= alen;
164 dest = (char __user *)dest + alen;
3d8fa456 165 alen = min(len, DATALEN_SEG);
1da177e4
LT
166 if (copy_to_user(dest, seg + 1, alen))
167 return -1;
1da177e4
LT
168 }
169 return 0;
170}
171
172void free_msg(struct msg_msg *msg)
173{
174 struct msg_msgseg *seg;
175
176 security_msg_msg_free(msg);
177
178 seg = msg->next;
179 kfree(msg);
180 while (seg != NULL) {
181 struct msg_msgseg *tmp = seg->next;
182 kfree(seg);
183 seg = tmp;
184 }
185}