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/* $OpenBSD: buffer.c,v 1.2 2004/07/12 09:22:38 dtucker Exp $ */
/*
* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/uio.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
#include <unistd.h>
#include "ntpd.h"
int buf_write(int, struct buf *);
void buf_enqueue(struct msgbuf *, struct buf *);
void buf_dequeue(struct msgbuf *, struct buf *);
struct buf *
buf_open(ssize_t len)
{
struct buf *buf;
if ((buf = calloc(1, sizeof(struct buf))) == NULL)
return (NULL);
if ((buf->buf = malloc(len)) == NULL) {
free(buf);
return (NULL);
}
buf->size = len;
return (buf);
}
int
buf_add(struct buf *buf, void *data, ssize_t len)
{
if (buf->wpos + len > buf->size)
return (-1);
memcpy(buf->buf + buf->wpos, data, len);
buf->wpos += len;
return (0);
}
int
buf_close(struct msgbuf *msgbuf, struct buf *buf)
{
buf_enqueue(msgbuf, buf);
return (1);
}
int
buf_write(int sock, struct buf *buf)
{
ssize_t n;
if ((n = write(sock, buf->buf + buf->rpos,
buf->size - buf->rpos)) == -1) {
if (errno == EAGAIN) /* cannot write immediately */
return (0);
else
return (-1);
}
if (n == 0) { /* connection closed */
errno = 0;
return (-2);
}
if (n < buf->size - buf->rpos) { /* not all data written yet */
buf->rpos += n;
return (0);
} else
return (1);
}
void
buf_free(struct buf *buf)
{
free(buf->buf);
free(buf);
}
void
msgbuf_init(struct msgbuf *msgbuf)
{
msgbuf->queued = 0;
msgbuf->fd = -1;
TAILQ_INIT(&msgbuf->bufs);
}
void
msgbuf_clear(struct msgbuf *msgbuf)
{
struct buf *buf;
while ((buf = TAILQ_FIRST(&msgbuf->bufs)) != NULL)
buf_dequeue(msgbuf, buf);
}
int
msgbuf_write(struct msgbuf *msgbuf)
{
/*
* possible race here
* when we cannot write out data completely from a buffer,
* we MUST return and NOT try to write out stuff from later buffers -
* the socket might have become writeable again
*/
struct iovec iov[IOV_MAX];
struct buf *buf, *next;
int i = 0;
ssize_t n;
bzero(&iov, sizeof(iov));
TAILQ_FOREACH(buf, &msgbuf->bufs, entries) {
if (i >= IOV_MAX)
break;
iov[i].iov_base = buf->buf + buf->rpos;
iov[i].iov_len = buf->size - buf->rpos;
i++;
}
if ((n = writev(msgbuf->fd, iov, i)) == -1) {
if (errno == EAGAIN) /* cannot write immediately */
return (0);
else
return (-1);
}
if (n == 0) { /* connection closed */
errno = 0;
return (-2);
}
for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0;
buf = next) {
next = TAILQ_NEXT(buf, entries);
if (n >= buf->size - buf->rpos) {
n -= buf->size - buf->rpos;
buf_dequeue(msgbuf, buf);
} else {
buf->rpos += n;
n = 0;
}
}
return (0);
}
void
buf_enqueue(struct msgbuf *msgbuf, struct buf *buf)
{
TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entries);
msgbuf->queued++;
}
void
buf_dequeue(struct msgbuf *msgbuf, struct buf *buf)
{
TAILQ_REMOVE(&msgbuf->bufs, buf, entries);
msgbuf->queued--;
buf_free(buf);
}
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