projects/linux·blob v3.0 · refs

147 lines · 2.8 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/ipc_namespace.h>
17#include <asm/uaccess.h>
18
19#include "util.h"
20
21DEFINE_SPINLOCK(mq_lock);
22
23/*
24 * The next 2 defines are here bc this is the only file
25 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
26 * and not CONFIG_IPC_NS.
27 */
28struct ipc_namespace init_ipc_ns = {
29 .count = ATOMIC_INIT(1),
30#ifdef CONFIG_POSIX_MQUEUE
31 .mq_queues_max = DFLT_QUEUESMAX,
32 .mq_msg_max = DFLT_MSGMAX,
33 .mq_msgsize_max = DFLT_MSGSIZEMAX,
34#endif
35 .user_ns = &init_user_ns,
36};
37
38atomic_t nr_ipc_ns = ATOMIC_INIT(1);
39
40struct msg_msgseg {
41 struct msg_msgseg* next;
42 /* the next part of the message follows immediately */
43};
44
45#define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg))
46#define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg))
47
48struct msg_msg *load_msg(const void __user *src, int len)
49{
50 struct msg_msg *msg;
51 struct msg_msgseg **pseg;
52 int err;
53 int alen;
54
55 alen = len;
56 if (alen > DATALEN_MSG)
57 alen = DATALEN_MSG;
58
59 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
60 if (msg == NULL)
61 return ERR_PTR(-ENOMEM);
62
63 msg->next = NULL;
64 msg->security = NULL;
65
66 if (copy_from_user(msg + 1, src, alen)) {
67 err = -EFAULT;
68 goto out_err;
69 }
70
71 len -= alen;
72 src = ((char __user *)src) + alen;
73 pseg = &msg->next;
74 while (len > 0) {
75 struct msg_msgseg *seg;
76 alen = len;
77 if (alen > DATALEN_SEG)
78 alen = DATALEN_SEG;
79 seg = kmalloc(sizeof(*seg) + alen,
80 GFP_KERNEL);
81 if (seg == NULL) {
82 err = -ENOMEM;
83 goto out_err;
84 }
85 *pseg = seg;
86 seg->next = NULL;
87 if (copy_from_user(seg + 1, src, alen)) {
88 err = -EFAULT;
89 goto out_err;
90 }
91 pseg = &seg->next;
92 len -= alen;
93 src = ((char __user *)src) + alen;
94 }
95
96 err = security_msg_msg_alloc(msg);
97 if (err)
98 goto out_err;
99
100 return msg;
101
102out_err:
103 free_msg(msg);
104 return ERR_PTR(err);
105}
106
107int store_msg(void __user *dest, struct msg_msg *msg, int len)
108{
109 int alen;
110 struct msg_msgseg *seg;
111
112 alen = len;
113 if (alen > DATALEN_MSG)
114 alen = DATALEN_MSG;
115 if (copy_to_user(dest, msg + 1, alen))
116 return -1;
117
118 len -= alen;
119 dest = ((char __user *)dest) + alen;
120 seg = msg->next;
121 while (len > 0) {
122 alen = len;
123 if (alen > DATALEN_SEG)
124 alen = DATALEN_SEG;
125 if (copy_to_user(dest, seg + 1, alen))
126 return -1;
127 len -= alen;
128 dest = ((char __user *)dest) + alen;
129 seg = seg->next;
130 }
131 return 0;
132}
133
134void free_msg(struct msg_msg *msg)
135{
136 struct msg_msgseg *seg;
137
138 security_msg_msg_free(msg);
139
140 seg = msg->next;
141 kfree(msg);
142 while (seg != NULL) {
143 struct msg_msgseg *tmp = seg->next;
144 kfree(seg);
145 seg = tmp;
146 }
147}