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