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 42 void 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 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 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 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 122 buf_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