freebsd-skq/usr.sbin/bhyve/iov.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2016 Jakub Klama <jceel@FreeBSD.org>.
* Copyright (c) 2018 Alexander Motin <mav@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <stdlib.h>
#include <string.h>
#include "iov.h"
void
seek_iov(const struct iovec *iov1, int niov1, struct iovec *iov2, int *niov2,
size_t seek)
{
size_t remainder = 0;
size_t left = seek;
int i, j;
for (i = 0; i < niov1; i++) {
size_t toseek = MIN(left, iov1[i].iov_len);
left -= toseek;
if (toseek == iov1[i].iov_len)
continue;
if (left == 0) {
remainder = toseek;
break;
}
}
for (j = i; j < niov1; j++) {
iov2[j - i].iov_base = (char *)iov1[j].iov_base + remainder;
iov2[j - i].iov_len = iov1[j].iov_len - remainder;
remainder = 0;
}
*niov2 = j - i;
}
size_t
count_iov(const struct iovec *iov, int niov)
{
size_t total = 0;
int i;
for (i = 0; i < niov; i++)
total += iov[i].iov_len;
return (total);
}
void
truncate_iov(struct iovec *iov, int *niov, size_t length)
{
size_t done = 0;
int i;
for (i = 0; i < *niov; i++) {
size_t toseek = MIN(length - done, iov[i].iov_len);
done += toseek;
if (toseek <= iov[i].iov_len) {
iov[i].iov_len = toseek;
*niov = i + 1;
return;
}
}
}
ssize_t
iov_to_buf(const struct iovec *iov, int niov, void **buf)
{
size_t ptr, total;
int i;
total = count_iov(iov, niov);
*buf = realloc(*buf, total);
if (*buf == NULL)
return (-1);
for (i = 0, ptr = 0; i < niov; i++) {
memcpy(*buf + ptr, iov[i].iov_base, iov[i].iov_len);
ptr += iov[i].iov_len;
}
return (total);
}
ssize_t
buf_to_iov(const void *buf, size_t buflen, struct iovec *iov, int niov,
size_t seek)
{
struct iovec *diov;
int ndiov, i;
size_t off = 0, len;
if (seek > 0) {
diov = malloc(sizeof(struct iovec) * niov);
seek_iov(iov, niov, diov, &ndiov, seek);
} else {
diov = iov;
ndiov = niov;
}
for (i = 0; i < ndiov && off < buflen; i++) {
len = MIN(diov[i].iov_len, buflen - off);
memcpy(diov[i].iov_base, buf + off, len);
off += len;
}
if (seek > 0)
free(diov);
return ((ssize_t)off);
}