1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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__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
42void
43seek_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
72size_t
73count_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
84void
85truncate_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
102ssize_t
103iov_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
121ssize_t
122buf_to_iov(const void *buf, size_t buflen, const struct iovec *iov, int niov,
123    size_t seek)
124{
125	struct iovec *diov;
126	size_t off = 0, len;
127	int  i;
128
129#ifndef __FreeBSD__
130	diov = NULL;
131#endif
132
133	if (seek > 0) {
134		int ndiov;
135
136		diov = malloc(sizeof(struct iovec) * niov);
137		seek_iov(iov, niov, diov, &ndiov, seek);
138		iov = diov;
139		niov = ndiov;
140	}
141
142	for (i = 0; i < niov && off < buflen; i++) {
143		len = MIN(iov[i].iov_len, buflen - off);
144		memcpy(iov[i].iov_base, buf + off, len);
145		off += len;
146	}
147
148	if (seek > 0)
149		free(diov);
150
151	return ((ssize_t)off);
152}
153
154