usr/src/cmd/bhyve/iov.c

   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((uint8_t *)*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, (const uint8_t *)buf + off, len);
 145                 off += len;
 146         }
 147
 148         if (seek > 0)
 149                 free(diov);
 150
 151         return ((ssize_t)off);
 152 }
 153