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/uio.h>
31 #include <errno.h>
32 #include <unistd.h>
33 
34 #include "atomicio.h"
35 
36 __RCSID("$MirOS: src/usr.bin/nc/atomicio.c,v 1.4 2005/11/23 18:04:10 tg Exp $");
37 
38 /*
39  * ensure all of data on socket comes through. f==read || f==vwrite
40  */
41 size_t
42 atomicio(f, fd, _s, n)
43 	ssize_t (*f) (int, void *, size_t);
44 	int fd;
45 	void *_s;
46 	size_t n;
47 {
48 	char *s = _s;
49 	size_t pos = 0;
50 	ssize_t res;
51 
52 	while (n > pos) {
53 		res = (f) (fd, s + pos, n - pos);
54 		switch (res) {
55 		case -1:
56 			if (errno == EINTR || errno == EAGAIN)
57 				continue;
58 			return 0;
59 		case 0:
60 			errno = EPIPE;
61 			return pos;
62 		default:
63 			pos += (u_int)res;
64 		}
65 	}
66 	return pos;
67 }
68