xref: /openbsd/usr.bin/ssh/atomicio.c (revision f24b2c8a)
1 /*
2  * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
3  * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include "includes.h"
28 RCSID("$OpenBSD: atomicio.c,v 1.14 2006/02/11 19:31:18 otto Exp $");
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