atomicio.c revision 162853 
1/* $OpenBSD: atomicio.c,v 1.23 2006/08/03 03:34:41 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 "includes.h"
30
31#include <sys/param.h>
32#include <sys/uio.h>
33
34#include <errno.h>
35#include <string.h>
36
37#include "atomicio.h"
38
39/*
40 * ensure all of data on socket comes through. f==read || f==vwrite
41 */
42size_t
43atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
44{
45	char *s = _s;
46	size_t pos = 0;
47	ssize_t res;
48
49	while (n > pos) {
50		res = (f) (fd, s + pos, n - pos);
51		switch (res) {
52		case -1:
53#ifdef EWOULDBLOCK
54			if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
55#else
56			if (errno == EINTR || errno == EAGAIN)
57#endif
58				continue;
59			return 0;
60		case 0:
61			errno = EPIPE;
62			return pos;
63		default:
64			pos += (size_t)res;
65		}
66	}
67	return (pos);
68}
69
70/*
71 * ensure all of data on socket comes through. f==readv || f==writev
72 */
73size_t
74atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
75    const struct iovec *_iov, int iovcnt)
76{
77	size_t pos = 0, rem;
78	ssize_t res;
79	struct iovec iov_array[IOV_MAX], *iov = iov_array;
80
81	if (iovcnt > IOV_MAX) {
82		errno = EINVAL;
83		return 0;
84	}
85	/* Make a copy of the iov array because we may modify it below */
86	memcpy(iov, _iov, iovcnt * sizeof(*_iov));
87
88	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
89		res = (f) (fd, iov, iovcnt);
90		switch (res) {
91		case -1:
92			if (errno == EINTR || errno == EAGAIN)
93				continue;
94			return 0;
95		case 0:
96			errno = EPIPE;
97			return pos;
98		default:
99			rem = (size_t)res;
100			pos += rem;
101			/* skip completed iov entries */
102			while (iovcnt > 0 && rem >= iov[0].iov_len) {
103				rem -= iov[0].iov_len;
104				iov++;
105				iovcnt--;
106			}
107			/* This shouldn't happen... */
108			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
109				errno = EFAULT;
110				return 0;
111			}
112			if (iovcnt == 0)
113				break;
114			/* update pointer in partially complete iov */
115			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
116			iov[0].iov_len -= rem;
117		}
118	}
119	return pos;
120}
121