atomicio.c revision 262566 
1/* $OpenBSD: atomicio.c,v 1.26 2010/09/22 22:58:51 djm 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#ifdef HAVE_POLL_H
36#include <poll.h>
37#else
38# ifdef HAVE_SYS_POLL_H
39#  include <sys/poll.h>
40# endif
41#endif
42#include <string.h>
43#include <unistd.h>
44
45#include "atomicio.h"
46
47/*
48 * ensure all of data on socket comes through. f==read || f==vwrite
49 */
50size_t
51atomicio6(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n,
52    int (*cb)(void *, size_t), void *cb_arg)
53{
54	char *s = _s;
55	size_t pos = 0;
56	ssize_t res;
57	struct pollfd pfd;
58
59#ifndef BROKEN_READ_COMPARISON
60	pfd.fd = fd;
61	pfd.events = f == read ? POLLIN : POLLOUT;
62#endif
63	while (n > pos) {
64		res = (f) (fd, s + pos, n - pos);
65		switch (res) {
66		case -1:
67			if (errno == EINTR)
68				continue;
69			if (errno == EAGAIN || errno == EWOULDBLOCK) {
70#ifndef BROKEN_READ_COMPARISON
71				(void)poll(&pfd, 1, -1);
72#endif
73				continue;
74			}
75			return 0;
76		case 0:
77			errno = EPIPE;
78			return pos;
79		default:
80			pos += (size_t)res;
81			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
82				errno = EINTR;
83				return pos;
84			}
85		}
86	}
87	return pos;
88}
89
90size_t
91atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
92{
93	return atomicio6(f, fd, _s, n, NULL, NULL);
94}
95
96/*
97 * ensure all of data on socket comes through. f==readv || f==writev
98 */
99size_t
100atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
101    const struct iovec *_iov, int iovcnt,
102    int (*cb)(void *, size_t), void *cb_arg)
103{
104	size_t pos = 0, rem;
105	ssize_t res;
106	struct iovec iov_array[IOV_MAX], *iov = iov_array;
107	struct pollfd pfd;
108
109	if (iovcnt > IOV_MAX) {
110		errno = EINVAL;
111		return 0;
112	}
113	/* Make a copy of the iov array because we may modify it below */
114	memcpy(iov, _iov, iovcnt * sizeof(*_iov));
115
116#ifndef BROKEN_READV_COMPARISON
117	pfd.fd = fd;
118	pfd.events = f == readv ? POLLIN : POLLOUT;
119#endif
120	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
121		res = (f) (fd, iov, iovcnt);
122		switch (res) {
123		case -1:
124			if (errno == EINTR)
125				continue;
126			if (errno == EAGAIN || errno == EWOULDBLOCK) {
127#ifndef BROKEN_READV_COMPARISON
128				(void)poll(&pfd, 1, -1);
129#endif
130				continue;
131			}
132			return 0;
133		case 0:
134			errno = EPIPE;
135			return pos;
136		default:
137			rem = (size_t)res;
138			pos += rem;
139			/* skip completed iov entries */
140			while (iovcnt > 0 && rem >= iov[0].iov_len) {
141				rem -= iov[0].iov_len;
142				iov++;
143				iovcnt--;
144			}
145			/* This shouldn't happen... */
146			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
147				errno = EFAULT;
148				return 0;
149			}
150			if (iovcnt == 0)
151				break;
152			/* update pointer in partially complete iov */
153			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
154			iov[0].iov_len -= rem;
155		}
156		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
157			errno = EINTR;
158			return pos;
159		}
160	}
161	return pos;
162}
163
164size_t
165atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
166    const struct iovec *_iov, int iovcnt)
167{
168	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
169}
170