xref: /openbsd/usr.bin/nc/atomicio.c (revision 78b63d65)
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 <sys/types.h>
27 #include <sys/uio.h>
28 
29 #include <errno.h>
30 #include <unistd.h>
31 
32 /*
33  * ensure all of data on socket comes through. f==read || f==write
34  */
35 ssize_t
36 atomicio(f, fd, _s, n)
37 	ssize_t (*f) ();
38 	int fd;
39 	void *_s;
40 	size_t n;
41 {
42 	char *s = _s;
43 	ssize_t res, pos = 0;
44 
45 	while (n > pos) {
46 		res = (f) (fd, s + pos, n - pos);
47 		switch (res) {
48 		case -1:
49 			if (errno == EINTR || errno == EAGAIN)
50 				continue;
51 		case 0:
52 			return (res);
53 		default:
54 			pos += res;
55 		}
56 	}
57 	return (pos);
58 }
59