projects/linux·blob v3.8 · refs

189 lines · 3.6 KiB

1/*
2 * linux/ipc/msgutil.c
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>
16#include <linux/msg.h>
17#include <linux/ipc_namespace.h>
18#include <linux/utsname.h>
19#include <linux/proc_fs.h>
20#include <asm/uaccess.h>
21
22#include "util.h"
23
24DEFINE_SPINLOCK(mq_lock);
25
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 = {
32 .count = ATOMIC_INIT(1),
33 .user_ns = &init_user_ns,
34 .proc_inum = PROC_IPC_INIT_INO,
35};
36
37atomic_t nr_ipc_ns = ATOMIC_INIT(1);
38
39struct msg_msgseg {
40 struct msg_msgseg* next;
41 /* the next part of the message follows immediately */
42};
43
44#define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg))
45#define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg))
46
47struct msg_msg *load_msg(const void __user *src, int len)
48{
49 struct msg_msg *msg;
50 struct msg_msgseg **pseg;
51 int err;
52 int alen;
53
54 alen = len;
55 if (alen > DATALEN_MSG)
56 alen = DATALEN_MSG;
57
58 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
59 if (msg == NULL)
60 return ERR_PTR(-ENOMEM);
61
62 msg->next = NULL;
63 msg->security = NULL;
64
65 if (copy_from_user(msg + 1, src, alen)) {
66 err = -EFAULT;
67 goto out_err;
68 }
69
70 len -= alen;
71 src = ((char __user *)src) + alen;
72 pseg = &msg->next;
73 while (len > 0) {
74 struct msg_msgseg *seg;
75 alen = len;
76 if (alen > DATALEN_SEG)
77 alen = DATALEN_SEG;
78 seg = kmalloc(sizeof(*seg) + alen,
79 GFP_KERNEL);
80 if (seg == NULL) {
81 err = -ENOMEM;
82 goto out_err;
83 }
84 *pseg = seg;
85 seg->next = NULL;
86 if (copy_from_user(seg + 1, src, alen)) {
87 err = -EFAULT;
88 goto out_err;
89 }
90 pseg = &seg->next;
91 len -= alen;
92 src = ((char __user *)src) + alen;
93 }
94
95 err = security_msg_msg_alloc(msg);
96 if (err)
97 goto out_err;
98
99 return msg;
100
101out_err:
102 free_msg(msg);
103 return ERR_PTR(err);
104}
105#ifdef CONFIG_CHECKPOINT_RESTORE
106struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
107{
108 struct msg_msgseg *dst_pseg, *src_pseg;
109 int len = src->m_ts;
110 int alen;
111
112 BUG_ON(dst == NULL);
113 if (src->m_ts > dst->m_ts)
114 return ERR_PTR(-EINVAL);
115
116 alen = len;
117 if (alen > DATALEN_MSG)
118 alen = DATALEN_MSG;
119
120 dst->next = NULL;
121 dst->security = NULL;
122
123 memcpy(dst + 1, src + 1, alen);
124
125 len -= alen;
126 dst_pseg = dst->next;
127 src_pseg = src->next;
128 while (len > 0) {
129 alen = len;
130 if (alen > DATALEN_SEG)
131 alen = DATALEN_SEG;
132 memcpy(dst_pseg + 1, src_pseg + 1, alen);
133 dst_pseg = dst_pseg->next;
134 len -= alen;
135 src_pseg = src_pseg->next;
136 }
137
138 dst->m_type = src->m_type;
139 dst->m_ts = src->m_ts;
140
141 return dst;
142}
143#else
144struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
145{
146 return ERR_PTR(-ENOSYS);
147}
148#endif
149int store_msg(void __user *dest, struct msg_msg *msg, int len)
150{
151 int alen;
152 struct msg_msgseg *seg;
153
154 alen = len;
155 if (alen > DATALEN_MSG)
156 alen = DATALEN_MSG;
157 if (copy_to_user(dest, msg + 1, alen))
158 return -1;
159
160 len -= alen;
161 dest = ((char __user *)dest) + alen;
162 seg = msg->next;
163 while (len > 0) {
164 alen = len;
165 if (alen > DATALEN_SEG)
166 alen = DATALEN_SEG;
167 if (copy_to_user(dest, seg + 1, alen))
168 return -1;
169 len -= alen;
170 dest = ((char __user *)dest) + alen;
171 seg = seg->next;
172 }
173 return 0;
174}
175
176void free_msg(struct msg_msg *msg)
177{
178 struct msg_msgseg *seg;
179
180 security_msg_msg_free(msg);
181
182 seg = msg->next;
183 kfree(msg);
184 while (seg != NULL) {
185 struct msg_msgseg *tmp = seg->next;
186 kfree(seg);
187 seg = tmp;
188 }
189}