1/* $OpenBSD: atomicio.c,v 1.30 2019/01/24 02:42:23 dtucker 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/uio.h>
30
31#include <errno.h>
32#include <poll.h>
33#include <string.h>
34#include <unistd.h>
35#include <limits.h>
36
37#include "atomicio.h"
38
39/*
40 * ensure all of data on socket comes through. f==read || f==vwrite
41 */
42size_t
43atomicio6(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n,
44    int (*cb)(void *, size_t), void *cb_arg)
45{
46	char *s = _s;
47	size_t pos = 0;
48	ssize_t res;
49	struct pollfd pfd;
50
51	pfd.fd = fd;
52	pfd.events = f == read ? POLLIN : POLLOUT;
53	while (n > pos) {
54		res = (f) (fd, s + pos, n - pos);
55		switch (res) {
56		case -1:
57			if (errno == EINTR) {
58				/* possible SIGALARM, update callback */
59				if (cb != NULL && cb(cb_arg, 0) == -1) {
60					errno = EINTR;
61					return pos;
62				}
63				continue;
64			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
65				(void)poll(&pfd, 1, -1);
66				continue;
67			}
68			return 0;
69		case 0:
70			errno = EPIPE;
71			return pos;
72		default:
73			pos += (size_t)res;
74			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
75				errno = EINTR;
76				return pos;
77			}
78		}
79	}
80	return pos;
81}
82
83size_t
84atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
85{
86	return atomicio6(f, fd, _s, n, NULL, NULL);
87}
88
89/*
90 * ensure all of data on socket comes through. f==readv || f==writev
91 */
92size_t
93atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
94    const struct iovec *_iov, int iovcnt,
95    int (*cb)(void *, size_t), void *cb_arg)
96{
97	size_t pos = 0, rem;
98	ssize_t res;
99	struct iovec iov_array[IOV_MAX], *iov = iov_array;
100	struct pollfd pfd;
101
102	if (iovcnt < 0 || iovcnt > IOV_MAX) {
103		errno = EINVAL;
104		return 0;
105	}
106	/* Make a copy of the iov array because we may modify it below */
107	memcpy(iov, _iov, (size_t)iovcnt * sizeof(*_iov));
108
109	pfd.fd = fd;
110	pfd.events = f == readv ? POLLIN : POLLOUT;
111	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
112		res = (f) (fd, iov, iovcnt);
113		switch (res) {
114		case -1:
115			if (errno == EINTR) {
116				/* possible SIGALARM, update callback */
117				if (cb != NULL && cb(cb_arg, 0) == -1) {
118					errno = EINTR;
119					return pos;
120				}
121				continue;
122			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
123				(void)poll(&pfd, 1, -1);
124				continue;
125			}
126			return 0;
127		case 0:
128			errno = EPIPE;
129			return pos;
130		default:
131			rem = (size_t)res;
132			pos += rem;
133			/* skip completed iov entries */
134			while (iovcnt > 0 && rem >= iov[0].iov_len) {
135				rem -= iov[0].iov_len;
136				iov++;
137				iovcnt--;
138			}
139			/* This shouldn't happen... */
140			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
141				errno = EFAULT;
142				return 0;
143			}
144			if (iovcnt == 0)
145				break;
146			/* update pointer in partially complete iov */
147			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
148			iov[0].iov_len -= rem;
149		}
150		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
151			errno = EINTR;
152			return pos;
153		}
154	}
155	return pos;
156}
157
158size_t
159atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
160    const struct iovec *_iov, int iovcnt)
161{
162	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
163}
164