1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2016 Jakub Klama <[email protected]>.
5 * Copyright (c) 2018 Alexander Motin <[email protected]>
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 __FBSDID("$FreeBSD$");
33
34 #include <sys/param.h>
35 #include <sys/types.h>
36 #include <sys/uio.h>
37
38 #include <stdlib.h>
39 #include <string.h>
40 #include "iov.h"
41
42 void
seek_iov(const struct iovec * iov1,int niov1,struct iovec * iov2,int * niov2,size_t seek)43 seek_iov(const struct iovec *iov1, int niov1, struct iovec *iov2, int *niov2,
44 size_t seek)
45 {
46 size_t remainder = 0;
47 size_t left = seek;
48 int i, j;
49
50 for (i = 0; i < niov1; i++) {
51 size_t toseek = MIN(left, iov1[i].iov_len);
52 left -= toseek;
53
54 if (toseek == iov1[i].iov_len)
55 continue;
56
57 if (left == 0) {
58 remainder = toseek;
59 break;
60 }
61 }
62
63 for (j = i; j < niov1; j++) {
64 iov2[j - i].iov_base = (char *)iov1[j].iov_base + remainder;
65 iov2[j - i].iov_len = iov1[j].iov_len - remainder;
66 remainder = 0;
67 }
68
69 *niov2 = j - i;
70 }
71
72 size_t
count_iov(const struct iovec * iov,int niov)73 count_iov(const struct iovec *iov, int niov)
74 {
75 size_t total = 0;
76 int i;
77
78 for (i = 0; i < niov; i++)
79 total += iov[i].iov_len;
80
81 return (total);
82 }
83
84 void
truncate_iov(struct iovec * iov,int * niov,size_t length)85 truncate_iov(struct iovec *iov, int *niov, size_t length)
86 {
87 size_t done = 0;
88 int i;
89
90 for (i = 0; i < *niov; i++) {
91 size_t toseek = MIN(length - done, iov[i].iov_len);
92 done += toseek;
93
94 if (toseek <= iov[i].iov_len) {
95 iov[i].iov_len = toseek;
96 *niov = i + 1;
97 return;
98 }
99 }
100 }
101
102 ssize_t
iov_to_buf(const struct iovec * iov,int niov,void ** buf)103 iov_to_buf(const struct iovec *iov, int niov, void **buf)
104 {
105 size_t ptr, total;
106 int i;
107
108 total = count_iov(iov, niov);
109 *buf = realloc(*buf, total);
110 if (*buf == NULL)
111 return (-1);
112
113 for (i = 0, ptr = 0; i < niov; i++) {
114 memcpy(*buf + ptr, iov[i].iov_base, iov[i].iov_len);
115 ptr += iov[i].iov_len;
116 }
117
118 return (total);
119 }
120
121 ssize_t
buf_to_iov(const void * buf,size_t buflen,struct iovec * iov,int niov,size_t seek)122 buf_to_iov(const void *buf, size_t buflen, struct iovec *iov, int niov,
123 size_t seek)
124 {
125 struct iovec *diov;
126 int ndiov, i;
127 size_t off = 0, len;
128
129 if (seek > 0) {
130 diov = malloc(sizeof(struct iovec) * niov);
131 seek_iov(iov, niov, diov, &ndiov, seek);
132 } else {
133 diov = iov;
134 ndiov = niov;
135 }
136
137 for (i = 0; i < ndiov && off < buflen; i++) {
138 len = MIN(diov[i].iov_len, buflen - off);
139 memcpy(diov[i].iov_base, buf + off, len);
140 off += len;
141 }
142
143 if (seek > 0)
144 free(diov);
145
146 return ((ssize_t)off);
147 }
148
149