atomicio.c revision 124208 
1/*
2 * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "includes.h"
27RCSID("$OpenBSD: atomicio.c,v 1.12 2003/07/31 15:50:16 avsm Exp $");
28
29#include "atomicio.h"
30
31/*
32 * ensure all of data on socket comes through. f==read || f==vwrite
33 */
34ssize_t
35atomicio(f, fd, _s, n)
36	ssize_t (*f) (int, void *, size_t);
37	int fd;
38	void *_s;
39	size_t n;
40{
41	char *s = _s;
42	ssize_t res, pos = 0;
43
44	while (n > pos) {
45		res = (f) (fd, s + pos, n - pos);
46		switch (res) {
47		case -1:
48#ifdef EWOULDBLOCK
49			if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
50#else
51			if (errno == EINTR || errno == EAGAIN)
52#endif
53				continue;
54		case 0:
55			return (res);
56		default:
57			pos += res;
58		}
59	}
60	return (pos);
61}
62