1/* $OpenBSD: atomicio.c,v 1.7 2005/05/26 01:01:08 avsm Exp $ */
2
3/*
4 * Copyright (c) 2005 Anil Madhavapeddy.  All rights served.
5 * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
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 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/types.h>
30#include <sys/event.h>
31#include <sys/time.h>
32#include <sys/uio.h>
33#include <errno.h>
34#include <unistd.h>
35#include "atomicio.h"
36
37extern int use_flowadv;
38extern int wait_for_flowadv(int fd);
39
40/*
41 * ensure all of data on socket comes through. f==read || f==vwrite
42 */
43size_t
44atomicio(f, fd, _s, n)
45	ssize_t (*f) (int, void *, size_t);
46	int fd;
47	void *_s;
48	size_t n;
49{
50	char *s = _s;
51	size_t pos = 0;
52	ssize_t res;
53
54	while (n > pos) {
55		res = (f) (fd, s + pos, n - pos);
56		switch (res) {
57		case -1:
58			if (errno == EINTR || errno == EAGAIN)
59				continue;
60			if (errno == ENOBUFS && use_flowadv && wait_for_flowadv(fd) == 0)
61				continue;
62			return 0;
63		case 0:
64			errno = EPIPE;
65			return pos;
66		default:
67			pos += (u_int)res;
68		}
69	}
70	return pos;
71}
72