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 <stdlib.h>
28 #include <errno.h>
29 #include "atomicio.h"
30 
31 /*
32  * ensure all of data on socket comes through. f==read || f==vwrite
33  */
34 size_t
35 atomicio(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 	size_t pos = 0;
43 	ssize_t res;
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 			return 0;
52 		case 0:
53 			errno = EPIPE;
54 			return pos;
55 		default:
56 			pos += (size_t)res;
57 		}
58 	}
59 	return (pos);
60 }
61 
62