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 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 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 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 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 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