1/* $OpenBSD: atomicio.c,v 1.1 2017/05/08 09:08:40 reyk 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				continue;
59			if (errno == EAGAIN) {
60				(void)poll(&pfd, 1, -1);
61				continue;
62			}
63			return 0;
64		case 0:
65			errno = EPIPE;
66			return pos;
67		default:
68			pos += (size_t)res;
69			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
70				errno = EINTR;
71				return pos;
72			}
73		}
74	}
75	return pos;
76}
77
78size_t
79atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
80{
81	return atomicio6(f, fd, _s, n, NULL, NULL);
82}
83
84/*
85 * ensure all of data on socket comes through. f==readv || f==writev
86 */
87size_t
88atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
89    const struct iovec *_iov, int iovcnt,
90    int (*cb)(void *, size_t), void *cb_arg)
91{
92	size_t pos = 0, rem;
93	ssize_t res;
94	struct iovec iov_array[IOV_MAX], *iov = iov_array;
95	struct pollfd pfd;
96
97	if (iovcnt < 0 || iovcnt > IOV_MAX) {
98		errno = EINVAL;
99		return 0;
100	}
101	/* Make a copy of the iov array because we may modify it below */
102	memcpy(iov, _iov, (size_t)iovcnt * sizeof(*_iov));
103
104	pfd.fd = fd;
105	pfd.events = f == readv ? POLLIN : POLLOUT;
106	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
107		res = (f) (fd, iov, iovcnt);
108		switch (res) {
109		case -1:
110			if (errno == EINTR)
111				continue;
112			if (errno == EAGAIN) {
113				(void)poll(&pfd, 1, -1);
114				continue;
115			}
116			return 0;
117		case 0:
118			errno = EPIPE;
119			return pos;
120		default:
121			rem = (size_t)res;
122			pos += rem;
123			/* skip completed iov entries */
124			while (iovcnt > 0 && rem >= iov[0].iov_len) {
125				rem -= iov[0].iov_len;
126				iov++;
127				iovcnt--;
128			}
129			/* This shouldn't happen... */
130			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
131				errno = EFAULT;
132				return 0;
133			}
134			if (iovcnt == 0)
135				break;
136			/* update pointer in partially complete iov */
137			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
138			iov[0].iov_len -= rem;
139		}
140		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
141			errno = EINTR;
142			return pos;
143		}
144	}
145	return pos;
146}
147
148size_t
149atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
150    const struct iovec *_iov, int iovcnt)
151{
152	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
153}
154