1 /* $OpenBSD: atomicio.c,v 1.9 2007/09/07 14:50:44 tobias Exp $ */
2
3 /*
4 * Copyright (c) 2006 Damien Miller. All rights reserved.
5 * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
6 * Copyright (c) 1995,1999 Theo de Raadt. All rights reserved.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #pragma ident "%Z%%M% %I% %E% SMI"
31
32 #include <sys/param.h>
33
34 #include <errno.h>
35 #include <poll.h>
36 #include <unistd.h>
37
38 #include "atomicio.h"
39
40 /*
41 * ensure all of data on socket comes through. f==read || f==vwrite
42 */
43 size_t
atomicio(ssize_t (* f)(int,void *,size_t),int fd,void * _s,size_t n)44 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
45 {
46 char *s = _s;
47 size_t pos = 0;
48 ssize_t res;
49 struct pollfd pfd;
50
51 pfd.fd = fd;
52 pfd.events = f == read ? POLLIN : POLLOUT;
53 while (n > pos) {
54 res = (f) (fd, s + pos, n - pos);
55 switch (res) {
56 case -1:
57 if (errno == EINTR)
58 continue;
59 if (errno == EAGAIN) {
60 (void) poll(&pfd, 1, -1);
61 continue;
62 }
63 return (0);
64 case 0:
65 errno = EPIPE;
66 return (pos);
67 default:
68 pos += (size_t)res;
69 }
70 }
71 return (pos);
72 }
73