1 /* $OpenBSD: atomicio.c,v 1.2 2015/01/16 06:40:06 deraadt Exp $ */
2 /*
3 * Copyright (c) 2006 Damien Miller. All rights reserved.
4 * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
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
31 #include <errno.h>
32 #include <poll.h>
33 #include <unistd.h>
34
35 #include "atomicio.h"
36
37 /*
38 * ensure all of data on socket comes through. f==read || f==vwrite
39 */
40 size_t
atomicio(ssize_t (* f)(int,void *,size_t),int fd,void * _s,size_t n)41 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
42 {
43 char *s = _s;
44 size_t pos = 0;
45 ssize_t res;
46 struct pollfd pfd;
47
48 pfd.fd = fd;
49 pfd.events = f == read ? POLLIN : POLLOUT;
50 while (n > pos) {
51 res = (f) (fd, s + pos, n - pos);
52 switch (res) {
53 case -1:
54 if (errno == EINTR)
55 continue;
56 if (errno == EAGAIN) {
57 (void)poll(&pfd, 1, -1);
58 continue;
59 }
60 return 0;
61 case 0:
62 errno = EPIPE;
63 return pos;
64 default:
65 pos += (size_t)res;
66 }
67 }
68 return (pos);
69 }
70