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/* $OpenBSD: atomicio.c,v 1.1 2008/06/09 21:06:10 mbalmer Exp $ */
/*
* Copyright (c) 2006 Damien Miller. All rights reserved.
* Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
* Copyright (c) 1995,1999 Theo de Raadt. All rights reserved.
* 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.
* 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 ``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 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/param.h>
#include <sys/uio.h>
#include <errno.h>
#include <poll.h>
#include <string.h>
#include <unistd.h>
#include "atomicio.h"
/*
* ensure all of data on socket comes through. f==read || f==vwrite
*/
size_t
atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
{
char *s = _s;
size_t pos = 0;
ssize_t res;
struct pollfd pfd;
pfd.fd = fd;
pfd.events = f == read ? POLLIN : POLLOUT;
while (n > pos) {
res = (f) (fd, s + pos, n - pos);
switch (res) {
case -1:
if (errno == EINTR)
continue;
if (errno == EAGAIN) {
(void)poll(&pfd, 1, -1);
continue;
}
return 0;
case 0:
errno = EPIPE;
return pos;
default:
pos += (size_t)res;
}
}
return (pos);
}
/*
* ensure all of data on socket comes through. f==readv || f==writev
*/
size_t
atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
const struct iovec *_iov, int iovcnt)
{
size_t pos = 0, rem;
ssize_t res;
struct iovec iov_array[IOV_MAX], *iov = iov_array;
struct pollfd pfd;
if (iovcnt > IOV_MAX) {
errno = EINVAL;
return 0;
}
/* Make a copy of the iov array because we may modify it below */
memcpy(iov, _iov, iovcnt * sizeof(*_iov));
pfd.fd = fd;
pfd.events = f == readv ? POLLIN : POLLOUT;
for (; iovcnt > 0 && iov[0].iov_len > 0;) {
res = (f) (fd, iov, iovcnt);
switch (res) {
case -1:
if (errno == EINTR)
continue;
if (errno == EAGAIN) {
(void)poll(&pfd, 1, -1);
continue;
}
return 0;
case 0:
errno = EPIPE;
return pos;
default:
rem = (size_t)res;
pos += rem;
/* skip completed iov entries */
while (iovcnt > 0 && rem >= iov[0].iov_len) {
rem -= iov[0].iov_len;
iov++;
iovcnt--;
}
/* This shouldn't happen... */
if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
errno = EFAULT;
return 0;
}
if (iovcnt == 0)
break;
/* update pointer in partially complete iov */
iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
iov[0].iov_len -= rem;
}
}
return pos;
}
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