msgutil.c revision e1082f45
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	memcpy(dst + 1, src + 1, alen);
121
122	len -= alen;
123	dst_pseg = dst->next;
124	src_pseg = src->next;
125	while (len > 0) {
126		alen = len;
127		if (alen > DATALEN_SEG)
128			alen = DATALEN_SEG;
129		memcpy(dst_pseg + 1, src_pseg + 1, alen);
130		dst_pseg = dst_pseg->next;
131		len -= alen;
132		src_pseg = src_pseg->next;
133	}
134
135	dst->m_type = src->m_type;
136	dst->m_ts = src->m_ts;
137
138	return dst;
139}
140#else
141struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
142{
143	return ERR_PTR(-ENOSYS);
144}
145#endif
146int store_msg(void __user *dest, struct msg_msg *msg, int len)
147{
148	int alen;
149	struct msg_msgseg *seg;
150
151	alen = len;
152	if (alen > DATALEN_MSG)
153		alen = DATALEN_MSG;
154	if (copy_to_user(dest, msg + 1, alen))
155		return -1;
156
157	len -= alen;
158	dest = ((char __user *)dest) + alen;
159	seg = msg->next;
160	while (len > 0) {
161		alen = len;
162		if (alen > DATALEN_SEG)
163			alen = DATALEN_SEG;
164		if (copy_to_user(dest, seg + 1, alen))
165			return -1;
166		len -= alen;
167		dest = ((char __user *)dest) + alen;
168		seg = seg->next;
169	}
170	return 0;
171}
172
173void free_msg(struct msg_msg *msg)
174{
175	struct msg_msgseg *seg;
176
177	security_msg_msg_free(msg);
178
179	seg = msg->next;
180	kfree(msg);
181	while (seg != NULL) {
182		struct msg_msgseg *tmp = seg->next;
183		kfree(seg);
184		seg = tmp;
185	}
186}
187