atomicio.c revision 323134 
1/* $OpenBSD: atomicio.c,v 1.28 2016/07/27 23:18:12 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#include <limits.h>
45
46#include "atomicio.h"
47
48/*
49 * ensure all of data on socket comes through. f==read || f==vwrite
50 */
51size_t
52atomicio6(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n,
53    int (*cb)(void *, size_t), void *cb_arg)
54{
55	char *s = _s;
56	size_t pos = 0;
57	ssize_t res;
58	struct pollfd pfd;
59
60#ifndef BROKEN_READ_COMPARISON
61	pfd.fd = fd;
62	pfd.events = f == read ? POLLIN : POLLOUT;
63#endif
64	while (n > pos) {
65		res = (f) (fd, s + pos, n - pos);
66		switch (res) {
67		case -1:
68			if (errno == EINTR)
69				continue;
70			if (errno == EAGAIN || errno == EWOULDBLOCK) {
71#ifndef BROKEN_READ_COMPARISON
72				(void)poll(&pfd, 1, -1);
73#endif
74				continue;
75			}
76			return 0;
77		case 0:
78			errno = EPIPE;
79			return pos;
80		default:
81			pos += (size_t)res;
82			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
83				errno = EINTR;
84				return pos;
85			}
86		}
87	}
88	return pos;
89}
90
91size_t
92atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
93{
94	return atomicio6(f, fd, _s, n, NULL, NULL);
95}
96
97/*
98 * ensure all of data on socket comes through. f==readv || f==writev
99 */
100size_t
101atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
102    const struct iovec *_iov, int iovcnt,
103    int (*cb)(void *, size_t), void *cb_arg)
104{
105	size_t pos = 0, rem;
106	ssize_t res;
107	struct iovec iov_array[IOV_MAX], *iov = iov_array;
108	struct pollfd pfd;
109
110	if (iovcnt < 0 || iovcnt > IOV_MAX) {
111		errno = EINVAL;
112		return 0;
113	}
114	/* Make a copy of the iov array because we may modify it below */
115	memcpy(iov, _iov, (size_t)iovcnt * sizeof(*_iov));
116
117#ifndef BROKEN_READV_COMPARISON
118	pfd.fd = fd;
119	pfd.events = f == readv ? POLLIN : POLLOUT;
120#endif
121	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
122		res = (f) (fd, iov, iovcnt);
123		switch (res) {
124		case -1:
125			if (errno == EINTR)
126				continue;
127			if (errno == EAGAIN || errno == EWOULDBLOCK) {
128#ifndef BROKEN_READV_COMPARISON
129				(void)poll(&pfd, 1, -1);
130#endif
131				continue;
132			}
133			return 0;
134		case 0:
135			errno = EPIPE;
136			return pos;
137		default:
138			rem = (size_t)res;
139			pos += rem;
140			/* skip completed iov entries */
141			while (iovcnt > 0 && rem >= iov[0].iov_len) {
142				rem -= iov[0].iov_len;
143				iov++;
144				iovcnt--;
145			}
146			/* This shouldn't happen... */
147			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
148				errno = EFAULT;
149				return 0;
150			}
151			if (iovcnt == 0)
152				break;
153			/* update pointer in partially complete iov */
154			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
155			iov[0].iov_len -= rem;
156		}
157		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
158			errno = EINTR;
159			return pos;
160		}
161	}
162	return pos;
163}
164
165size_t
166atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
167    const struct iovec *_iov, int iovcnt)
168{
169	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
170}
171