1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* iov.h - helpers for using (partial) iovecs.
*
* Copyright Red Hat
* Author: Laurent Vivier <lvivier@redhat.com>
*
* This file also contains code originally from QEMU include/qemu/iov.h
* and licensed under the following terms:
*
* Copyright (C) 2010 Red Hat, Inc.
*
* Author(s):
* Amit Shah <amit.shah@redhat.com>
* Michael Tokarev <mjt@tls.msk.ru>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include <sys/socket.h>
#include "util.h"
#include "iov.h"
/**
* iov_from_buf - Copy data from a buffer to an I/O vector (struct iovec)
* efficiently.
*
* @iov: Pointer to the array of struct iovec describing the
* scatter/gather I/O vector.
* @iov_cnt: Number of elements in the iov array.
* @offset: Byte offset in the iov array where copying should start.
* @buf: Pointer to the source buffer containing the data to copy.
* @bytes: Total number of bytes to copy from buf to iov.
*
* Returns: The number of bytes successfully copied.
*/
/* cppcheck-suppress unusedFunction */
size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
size_t offset, const void *buf, size_t bytes)
{
unsigned int i;
size_t copied;
if (__builtin_constant_p(bytes) && iov_cnt &&
offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
memcpy((char *)iov[0].iov_base + offset, buf, bytes);
return bytes;
}
/* skipping offset bytes in the iovec */
for (i = 0; i < iov_cnt && offset >= iov[i].iov_len; i++)
offset -= iov[i].iov_len;
/* copying data */
for (copied = 0; copied < bytes && i < iov_cnt; i++) {
size_t len = MIN(iov[i].iov_len - offset, bytes - copied);
memcpy((char *)iov[i].iov_base + offset, (char *)buf + copied,
len);
copied += len;
offset = 0;
}
return copied;
}
/**
* iov_to_buf - Copy data from a scatter/gather I/O vector (struct iovec) to
* a buffer efficiently.
*
* @iov: Pointer to the array of struct iovec describing the scatter/gather
* I/O vector.
* @iov_cnt: Number of elements in the iov array.
* @offset: Offset within the first element of iov from where copying should start.
* @buf: Pointer to the destination buffer where data will be copied.
* @bytes: Total number of bytes to copy from iov to buf.
*
* Returns: The number of bytes successfully copied.
*/
/* cppcheck-suppress unusedFunction */
size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
size_t offset, void *buf, size_t bytes)
{
unsigned int i;
size_t copied;
if (__builtin_constant_p(bytes) && iov_cnt &&
offset <= iov[0].iov_len && bytes <= iov[0].iov_len - offset) {
memcpy(buf, (char *)iov[0].iov_base + offset, bytes);
return bytes;
}
/* skipping offset bytes in the iovec */
for (i = 0; i < iov_cnt && offset >= iov[i].iov_len; i++)
offset -= iov[i].iov_len;
/* copying data */
for (copied = 0; copied < bytes && i < iov_cnt; i++) {
size_t len = MIN(iov[i].iov_len - offset, bytes - copied);
memcpy((char *)buf + copied, (char *)iov[i].iov_base + offset,
len);
copied += len;
offset = 0;
}
return copied;
}
/**
* iov_size - Calculate the total size of a scatter/gather I/O vector
* (struct iovec).
*
* @iov: Pointer to the array of struct iovec describing the
* scatter/gather I/O vector.
* @iov_cnt: Number of elements in the iov array.
*
* Returns: The total size in bytes.
*/
/* cppcheck-suppress unusedFunction */
size_t iov_size(const struct iovec *iov, size_t iov_cnt)
{
unsigned int i;
size_t len;
for (i = 0, len = 0; i < iov_cnt; i++)
len += iov[i].iov_len;
return len;
}
/**
* iov_copy - Copy data from one scatter/gather I/O vector (struct iovec) to
* another.
*
* @dst_iov: Pointer to the destination array of struct iovec describing
* the scatter/gather I/O vector to copy to.
* @dst_iov_cnt: Number of elements in the destination iov array.
* @iov: Pointer to the source array of struct iovec describing
* the scatter/gather I/O vector to copy from.
* @iov_cnt: Number of elements in the source iov array.
* @offset: Offset within the source iov from where copying should start.
* @bytes: Total number of bytes to copy from iov to dst_iov.
*
* Returns: The number of elements successfully copied to the destination
* iov array.
*/
/* cppcheck-suppress unusedFunction */
unsigned iov_copy(struct iovec *dst_iov, size_t dst_iov_cnt,
const struct iovec *iov, size_t iov_cnt,
size_t offset, size_t bytes)
{
unsigned int i, j;
/* skipping offset bytes in the iovec */
for (i = 0; i < iov_cnt && offset >= iov[i].iov_len; i++)
offset -= iov[i].iov_len;
/* copying data */
for (j = 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) {
size_t len = MIN(bytes, iov[i].iov_len - offset);
dst_iov[j].iov_base = (char *)iov[i].iov_base + offset;
dst_iov[j].iov_len = len;
j++;
bytes -= len;
offset = 0;
}
return j;
}
|
