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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  */
51 size_t
atomicio6(ssize_t (* f)(int,void *,size_t),int fd,void * _s,size_t n,int (* cb)(void *,size_t),void * cb_arg)52 atomicio6(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 
91 size_t
atomicio(ssize_t (* f)(int,void *,size_t),int fd,void * _s,size_t n)92 atomicio(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  */
100 size_t
atomiciov6(ssize_t (* f)(int,const struct iovec *,int),int fd,const struct iovec * _iov,int iovcnt,int (* cb)(void *,size_t),void * cb_arg)101 atomiciov6(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 
165 size_t
atomiciov(ssize_t (* f)(int,const struct iovec *,int),int fd,const struct iovec * _iov,int iovcnt)166 atomiciov(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