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 "includes.h"
30
31#include <sys/uio.h>
32
33#include <errno.h>
34#ifdef HAVE_POLL_H
35#include <poll.h>
36#else
37# ifdef HAVE_SYS_POLL_H
38#  include <sys/poll.h>
39# endif
40#endif
41#include <string.h>
42#include <unistd.h>
43#include <limits.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#ifndef BROKEN_READ_COMPARISON
61	pfd.events = f == read ? POLLIN : POLLOUT;
62#else
63	pfd.events = POLLIN|POLLOUT;
64#endif
65	while (n > pos) {
66		res = (f) (fd, s + pos, n - pos);
67		switch (res) {
68		case -1:
69			if (errno == EINTR) {
70				/* possible SIGALARM, update callback */
71				if (cb != NULL && cb(cb_arg, 0) == -1) {
72					errno = EINTR;
73					return pos;
74				}
75				continue;
76			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
77				(void)poll(&pfd, 1, -1);
78				continue;
79			}
80			return 0;
81		case 0:
82			errno = EPIPE;
83			return pos;
84		default:
85			pos += (size_t)res;
86			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
87				errno = EINTR;
88				return pos;
89			}
90		}
91	}
92	return pos;
93}
94
95size_t
96atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
97{
98	return atomicio6(f, fd, _s, n, NULL, NULL);
99}
100
101/*
102 * ensure all of data on socket comes through. f==readv || f==writev
103 */
104size_t
105atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
106    const struct iovec *_iov, int iovcnt,
107    int (*cb)(void *, size_t), void *cb_arg)
108{
109	size_t pos = 0, rem;
110	ssize_t res;
111	struct iovec iov_array[IOV_MAX], *iov = iov_array;
112	struct pollfd pfd;
113
114	if (iovcnt < 0 || iovcnt > IOV_MAX) {
115		errno = EINVAL;
116		return 0;
117	}
118	/* Make a copy of the iov array because we may modify it below */
119	memcpy(iov, _iov, (size_t)iovcnt * sizeof(*_iov));
120
121	pfd.fd = fd;
122#ifndef BROKEN_READV_COMPARISON
123	pfd.events = f == readv ? POLLIN : POLLOUT;
124#else
125	pfd.events = POLLIN|POLLOUT;
126#endif
127	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
128		res = (f) (fd, iov, iovcnt);
129		switch (res) {
130		case -1:
131			if (errno == EINTR) {
132				/* possible SIGALARM, update callback */
133				if (cb != NULL && cb(cb_arg, 0) == -1) {
134					errno = EINTR;
135					return pos;
136				}
137				continue;
138			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
139				(void)poll(&pfd, 1, -1);
140				continue;
141			}
142			return 0;
143		case 0:
144			errno = EPIPE;
145			return pos;
146		default:
147			rem = (size_t)res;
148			pos += rem;
149			/* skip completed iov entries */
150			while (iovcnt > 0 && rem >= iov[0].iov_len) {
151				rem -= iov[0].iov_len;
152				iov++;
153				iovcnt--;
154			}
155			/* This shouldn't happen... */
156			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
157				errno = EFAULT;
158				return 0;
159			}
160			if (iovcnt == 0)
161				break;
162			/* update pointer in partially complete iov */
163			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
164			iov[0].iov_len -= rem;
165		}
166		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
167			errno = EINTR;
168			return pos;
169		}
170	}
171	return pos;
172}
173
174size_t
175atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
176    const struct iovec *_iov, int iovcnt)
177{
178	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
179}
180