1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2016 Jakub Klama <jceel@FreeBSD.org>.
5 * Copyright (c) 2018 Alexander Motin <mav@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer
13 * in this position and unchanged.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/param.h>
32 #include <sys/types.h>
33 #include <sys/uio.h>
34
35 #include <stdlib.h>
36 #include <string.h>
37 #include "iov.h"
38
39 void
seek_iov(const struct iovec * iov1,int niov1,struct iovec * iov2,int * niov2,size_t seek)40 seek_iov(const struct iovec *iov1, int niov1, struct iovec *iov2, int *niov2,
41 size_t seek)
42 {
43 size_t remainder = 0;
44 size_t left = seek;
45 int i, j;
46
47 for (i = 0; i < niov1; i++) {
48 size_t toseek = MIN(left, iov1[i].iov_len);
49 left -= toseek;
50
51 if (toseek == iov1[i].iov_len)
52 continue;
53
54 if (left == 0) {
55 remainder = toseek;
56 break;
57 }
58 }
59
60 for (j = i; j < niov1; j++) {
61 iov2[j - i].iov_base = (char *)iov1[j].iov_base + remainder;
62 iov2[j - i].iov_len = iov1[j].iov_len - remainder;
63 remainder = 0;
64 }
65
66 *niov2 = j - i;
67 }
68
69 size_t
count_iov(const struct iovec * iov,int niov)70 count_iov(const struct iovec *iov, int niov)
71 {
72 size_t total = 0;
73 int i;
74
75 for (i = 0; i < niov; i++)
76 total += iov[i].iov_len;
77
78 return (total);
79 }
80
81 void
truncate_iov(struct iovec * iov,int * niov,size_t length)82 truncate_iov(struct iovec *iov, int *niov, size_t length)
83 {
84 size_t done = 0;
85 int i;
86
87 for (i = 0; i < *niov; i++) {
88 size_t toseek = MIN(length - done, iov[i].iov_len);
89 done += toseek;
90
91 if (toseek <= iov[i].iov_len) {
92 iov[i].iov_len = toseek;
93 *niov = i + 1;
94 return;
95 }
96 }
97 }
98
99 ssize_t
iov_to_buf(const struct iovec * iov,int niov,void ** buf)100 iov_to_buf(const struct iovec *iov, int niov, void **buf)
101 {
102 size_t ptr, total;
103 int i;
104
105 total = count_iov(iov, niov);
106 *buf = realloc(*buf, total);
107 if (*buf == NULL)
108 return (-1);
109
110 for (i = 0, ptr = 0; i < niov; i++) {
111 memcpy((uint8_t *)*buf + ptr, iov[i].iov_base, iov[i].iov_len);
112 ptr += iov[i].iov_len;
113 }
114
115 return (total);
116 }
117
118 ssize_t
buf_to_iov(const void * buf,size_t buflen,const struct iovec * iov,int niov,size_t seek)119 buf_to_iov(const void *buf, size_t buflen, const struct iovec *iov, int niov,
120 size_t seek)
121 {
122 struct iovec *diov;
123 size_t off = 0, len;
124 int i;
125
126 if (seek > 0) {
127 int ndiov;
128
129 diov = malloc(sizeof(struct iovec) * niov);
130 seek_iov(iov, niov, diov, &ndiov, seek);
131 iov = diov;
132 niov = ndiov;
133 }
134
135 for (i = 0; i < niov && off < buflen; i++) {
136 len = MIN(iov[i].iov_len, buflen - off);
137 memcpy(iov[i].iov_base, (const uint8_t *)buf + off, len);
138 off += len;
139 }
140
141 if (seek > 0)
142 free(diov);
143
144 return ((ssize_t)off);
145 }
146
147