xref: /openbsd/usr.bin/ssh/atomicio.c (revision 7ef31a41)
1 /* $OpenBSD: atomicio.c,v 1.16 2006/03/25 13:17:01 djm Exp $ */
2 /*
3  * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
4  * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include "includes.h"
29 
30 #include "atomicio.h"
31 
32 /*
33  * ensure all of data on socket comes through. f==read || f==vwrite
34  */
35 size_t
36 atomicio(f, fd, _s, n)
37 	ssize_t (*f) (int, void *, size_t);
38 	int fd;
39 	void *_s;
40 	size_t n;
41 {
42 	char *s = _s;
43 	size_t pos = 0;
44 	ssize_t res;
45 
46 	while (n > pos) {
47 		res = (f) (fd, s + pos, n - pos);
48 		switch (res) {
49 		case -1:
50 			if (errno == EINTR || errno == EAGAIN)
51 				continue;
52 			return 0;
53 		case 0:
54 			errno = EPIPE;
55 			return pos;
56 		default:
57 			pos += (size_t)res;
58 		}
59 	}
60 	return (pos);
61 }
62