1 /* $OpenBSD: atomicio.c,v 1.2 2012/12/04 02:38:51 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 <sys/types.h>
30 #include <sys/uio.h>
31
32 #include <errno.h>
33 #include <poll.h>
34 #include <string.h>
35 #include <limits.h>
36 #include <unistd.h>
37
38 #include "atomicio.h"
39
40 /*
41 * ensure all of data on socket comes through. f==read || f==vwrite
42 */
43 size_t
atomicio(ssize_t (* f)(int,void *,size_t),int fd,void * _s,size_t n)44 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
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 }
70 }
71 return (pos);
72 }
73
74 /*
75 * ensure all of data on socket comes through. f==readv || f==writev
76 */
77 size_t
atomiciov(ssize_t (* f)(int,const struct iovec *,int),int fd,const struct iovec * _iov,int iovcnt)78 atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
79 const struct iovec *_iov, int iovcnt)
80 {
81 size_t pos = 0, rem;
82 ssize_t res;
83 struct iovec iov_array[IOV_MAX], *iov = iov_array;
84 struct pollfd pfd;
85
86 if (iovcnt > IOV_MAX) {
87 errno = EINVAL;
88 return 0;
89 }
90 /* Make a copy of the iov array because we may modify it below */
91 memcpy(iov, _iov, iovcnt * sizeof(*_iov));
92
93 pfd.fd = fd;
94 pfd.events = f == readv ? POLLIN : POLLOUT;
95 for (; iovcnt > 0 && iov[0].iov_len > 0;) {
96 res = (f) (fd, iov, iovcnt);
97 switch (res) {
98 case -1:
99 if (errno == EINTR)
100 continue;
101 if (errno == EAGAIN) {
102 (void)poll(&pfd, 1, -1);
103 continue;
104 }
105 return 0;
106 case 0:
107 errno = EPIPE;
108 return pos;
109 default:
110 rem = (size_t)res;
111 pos += rem;
112 /* skip completed iov entries */
113 while (iovcnt > 0 && rem >= iov[0].iov_len) {
114 rem -= iov[0].iov_len;
115 iov++;
116 iovcnt--;
117 }
118 /* This shouldn't happen... */
119 if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
120 errno = EFAULT;
121 return 0;
122 }
123 if (iovcnt == 0)
124 break;
125 /* update pointer in partially complete iov */
126 iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
127 iov[0].iov_len -= rem;
128 }
129 }
130 return pos;
131 }
132