xref: /freebsd/crypto/openssh/atomicio.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /* $OpenBSD: atomicio.c,v 1.23 2006/08/03 03:34:41 deraadt 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 #include <string.h>
36 
37 #include "atomicio.h"
38 
39 /*
40  * ensure all of data on socket comes through. f==read || f==vwrite
41  */
42 size_t
43 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
44 {
45 	char *s = _s;
46 	size_t pos = 0;
47 	ssize_t res;
48 
49 	while (n > pos) {
50 		res = (f) (fd, s + pos, n - pos);
51 		switch (res) {
52 		case -1:
53 #ifdef EWOULDBLOCK
54 			if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
55 #else
56 			if (errno == EINTR || errno == EAGAIN)
57 #endif
58 				continue;
59 			return 0;
60 		case 0:
61 			errno = EPIPE;
62 			return pos;
63 		default:
64 			pos += (size_t)res;
65 		}
66 	}
67 	return (pos);
68 }
69 
70 /*
71  * ensure all of data on socket comes through. f==readv || f==writev
72  */
73 size_t
74 atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
75     const struct iovec *_iov, int iovcnt)
76 {
77 	size_t pos = 0, rem;
78 	ssize_t res;
79 	struct iovec iov_array[IOV_MAX], *iov = iov_array;
80 
81 	if (iovcnt > IOV_MAX) {
82 		errno = EINVAL;
83 		return 0;
84 	}
85 	/* Make a copy of the iov array because we may modify it below */
86 	memcpy(iov, _iov, iovcnt * sizeof(*_iov));
87 
88 	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
89 		res = (f) (fd, iov, iovcnt);
90 		switch (res) {
91 		case -1:
92 			if (errno == EINTR || errno == EAGAIN)
93 				continue;
94 			return 0;
95 		case 0:
96 			errno = EPIPE;
97 			return pos;
98 		default:
99 			rem = (size_t)res;
100 			pos += rem;
101 			/* skip completed iov entries */
102 			while (iovcnt > 0 && rem >= iov[0].iov_len) {
103 				rem -= iov[0].iov_len;
104 				iov++;
105 				iovcnt--;
106 			}
107 			/* This shouldn't happen... */
108 			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
109 				errno = EFAULT;
110 				return 0;
111 			}
112 			if (iovcnt == 0)
113 				break;
114 			/* update pointer in partially complete iov */
115 			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
116 			iov[0].iov_len -= rem;
117 		}
118 	}
119 	return pos;
120 }
121