msgutil.c revision be5f4b33
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	(int)(PAGE_SIZE-sizeof(struct msg_msg))
45#define DATALEN_SEG	(int)(PAGE_SIZE-sizeof(struct msg_msgseg))
46
47
48static struct msg_msg *alloc_msg(int len)
49{
50	struct msg_msg *msg;
51	struct msg_msgseg **pseg;
52	int alen;
53
54	alen = min(len, DATALEN_MSG);
55	msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
56	if (msg == NULL)
57		return NULL;
58
59	msg->next = NULL;
60	msg->security = NULL;
61
62	len -= alen;
63	pseg = &msg->next;
64	while (len > 0) {
65		struct msg_msgseg *seg;
66		alen = min(len, DATALEN_SEG);
67		seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL);
68		if (seg == NULL)
69			goto out_err;
70		*pseg = seg;
71		seg->next = NULL;
72		pseg = &seg->next;
73		len -= alen;
74	}
75
76	return msg;
77
78out_err:
79	free_msg(msg);
80	return NULL;
81}
82
83struct msg_msg *load_msg(const void __user *src, int len)
84{
85	struct msg_msg *msg;
86	struct msg_msgseg *seg;
87	int err;
88	int alen;
89
90	msg = alloc_msg(len);
91	if (msg == NULL)
92		return ERR_PTR(-ENOMEM);
93
94	alen = min(len, DATALEN_MSG);
95	if (copy_from_user(msg + 1, src, alen)) {
96		err = -EFAULT;
97		goto out_err;
98	}
99
100	len -= alen;
101	src = ((char __user *)src) + alen;
102	seg = msg->next;
103	while (len > 0) {
104		alen = min(len, DATALEN_SEG);
105		if (copy_from_user(seg + 1, src, alen)) {
106			err = -EFAULT;
107			goto out_err;
108		}
109		seg = seg->next;
110		len -= alen;
111		src = ((char __user *)src) + alen;
112	}
113
114	err = security_msg_msg_alloc(msg);
115	if (err)
116		goto out_err;
117
118	return msg;
119
120out_err:
121	free_msg(msg);
122	return ERR_PTR(err);
123}
124#ifdef CONFIG_CHECKPOINT_RESTORE
125struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
126{
127	struct msg_msgseg *dst_pseg, *src_pseg;
128	int len = src->m_ts;
129	int alen;
130
131	BUG_ON(dst == NULL);
132	if (src->m_ts > dst->m_ts)
133		return ERR_PTR(-EINVAL);
134
135	alen = min(len, DATALEN_MSG);
136	memcpy(dst + 1, src + 1, alen);
137
138	len -= alen;
139	dst_pseg = dst->next;
140	src_pseg = src->next;
141	while (len > 0) {
142		alen = min(len, DATALEN_SEG);
143		memcpy(dst_pseg + 1, src_pseg + 1, alen);
144		dst_pseg = dst_pseg->next;
145		len -= alen;
146		src_pseg = src_pseg->next;
147	}
148
149	dst->m_type = src->m_type;
150	dst->m_ts = src->m_ts;
151
152	return dst;
153}
154#else
155struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
156{
157	return ERR_PTR(-ENOSYS);
158}
159#endif
160int store_msg(void __user *dest, struct msg_msg *msg, int len)
161{
162	int alen;
163	struct msg_msgseg *seg;
164
165	alen = min(len, DATALEN_MSG);
166	if (copy_to_user(dest, msg + 1, alen))
167		return -1;
168
169	len -= alen;
170	dest = ((char __user *)dest) + alen;
171	seg = msg->next;
172	while (len > 0) {
173		alen = min(len, DATALEN_SEG);
174		if (copy_to_user(dest, seg + 1, alen))
175			return -1;
176		len -= alen;
177		dest = ((char __user *)dest) + alen;
178		seg = seg->next;
179	}
180	return 0;
181}
182
183void free_msg(struct msg_msg *msg)
184{
185	struct msg_msgseg *seg;
186
187	security_msg_msg_free(msg);
188
189	seg = msg->next;
190	kfree(msg);
191	while (seg != NULL) {
192		struct msg_msgseg *tmp = seg->next;
193		kfree(seg);
194		seg = tmp;
195	}
196}
197