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 #include <sys/param.h>
31
32 #include <errno.h>
33 #include <poll.h>
34 #include <unistd.h>
35
36 #include "atomicio.h"
37
38 /*
39 * ensure all of data on socket comes through. f==read || f==vwrite
40 */
41 size_t
atomicio(ssize_t (* f)(int,void *,size_t),int fd,void * _s,size_t n)42 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
43 {
44 char *s = _s;
45 size_t pos = 0;
46 ssize_t res;
47 struct pollfd pfd;
48
49 pfd.fd = fd;
50 pfd.events = f == read ? POLLIN : POLLOUT;
51 while (n > pos) {
52 res = (f) (fd, s + pos, n - pos);
53 switch (res) {
54 case -1:
55 if (errno == EINTR)
56 continue;
57 if (errno == EAGAIN) {
58 (void) poll(&pfd, 1, -1);
59 continue;
60 }
61 return (0);
62 case 0:
63 errno = EPIPE;
64 return (pos);
65 default:
66 pos += (size_t)res;
67 }
68 }
69 return (pos);
70 }
71