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/cdefs.h>
32
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <sys/uio.h>
36
37 #include <stdlib.h>
38 #include <string.h>
39 #include "iov.h"
40
41 void
seek_iov(const struct iovec * iov1,int niov1,struct iovec * iov2,int * niov2,size_t seek)42 seek_iov(const struct iovec *iov1, int niov1, struct iovec *iov2, int *niov2,
43 size_t seek)
44 {
45 size_t remainder = 0;
46 size_t left = seek;
47 int i, j;
48
49 for (i = 0; i < niov1; i++) {
50 size_t toseek = MIN(left, iov1[i].iov_len);
51 left -= toseek;
52
53 if (toseek == iov1[i].iov_len)
54 continue;
55
56 if (left == 0) {
57 remainder = toseek;
58 break;
59 }
60 }
61
62 for (j = i; j < niov1; j++) {
63 iov2[j - i].iov_base = (char *)iov1[j].iov_base + remainder;
64 iov2[j - i].iov_len = iov1[j].iov_len - remainder;
65 remainder = 0;
66 }
67
68 *niov2 = j - i;
69 }
70
71 size_t
count_iov(const struct iovec * iov,int niov)72 count_iov(const struct iovec *iov, int niov)
73 {
74 size_t total = 0;
75 int i;
76
77 for (i = 0; i < niov; i++)
78 total += iov[i].iov_len;
79
80 return (total);
81 }
82
83 void
truncate_iov(struct iovec * iov,int * niov,size_t length)84 truncate_iov(struct iovec *iov, int *niov, size_t length)
85 {
86 size_t done = 0;
87 int i;
88
89 for (i = 0; i < *niov; i++) {
90 size_t toseek = MIN(length - done, iov[i].iov_len);
91 done += toseek;
92
93 if (toseek <= iov[i].iov_len) {
94 iov[i].iov_len = toseek;
95 *niov = i + 1;
96 return;
97 }
98 }
99 }
100
101 ssize_t
iov_to_buf(const struct iovec * iov,int niov,void ** buf)102 iov_to_buf(const struct iovec *iov, int niov, void **buf)
103 {
104 size_t ptr, total;
105 int i;
106
107 total = count_iov(iov, niov);
108 *buf = realloc(*buf, total);
109 if (*buf == NULL)
110 return (-1);
111
112 for (i = 0, ptr = 0; i < niov; i++) {
113 memcpy((uint8_t *)*buf + ptr, iov[i].iov_base, iov[i].iov_len);
114 ptr += iov[i].iov_len;
115 }
116
117 return (total);
118 }
119
120 ssize_t
buf_to_iov(const void * buf,size_t buflen,const struct iovec * iov,int niov,size_t seek)121 buf_to_iov(const void *buf, size_t buflen, const struct iovec *iov, int niov,
122 size_t seek)
123 {
124 struct iovec *diov;
125 size_t off = 0, len;
126 int i;
127
128 #ifndef __FreeBSD__
129 diov = NULL;
130 #endif
131
132 if (seek > 0) {
133 int ndiov;
134
135 diov = malloc(sizeof(struct iovec) * niov);
136 seek_iov(iov, niov, diov, &ndiov, seek);
137 iov = diov;
138 niov = ndiov;
139 }
140
141 for (i = 0; i < niov && off < buflen; i++) {
142 len = MIN(iov[i].iov_len, buflen - off);
143 memcpy(iov[i].iov_base, (const uint8_t *)buf + off, len);
144 off += len;
145 }
146
147 if (seek > 0)
148 free(diov);
149
150 return ((ssize_t)off);
151 }
152
153