1 /* $OpenBSD: atomicio.c,v 1.25 2007/06/25 12:02:27 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 <sys/param.h>
30 #include <sys/uio.h>
31
32 #include <errno.h>
33 #include <poll.h>
34 #include <string.h>
35 #include <unistd.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
atomicio(ssize_t (* f)(int,void *,size_t),int fd,void * _s,size_t n)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 struct pollfd pfd;
49
50 pfd.fd = fd;
51 pfd.events = f == read ? POLLIN : POLLOUT;
52 while (n > pos) {
53 res = (f) (fd, s + pos, n - pos);
54 switch (res) {
55 case -1:
56 if (errno == EINTR)
57 continue;
58 if (errno == EAGAIN) {
59 (void)poll(&pfd, 1, -1);
60 continue;
61 }
62 return 0;
63 case 0:
64 errno = EPIPE;
65 return pos;
66 default:
67 pos += (size_t)res;
68 }
69 }
70 return (pos);
71 }
72
73 /*
74 * ensure all of data on socket comes through. f==readv || f==writev
75 */
76 size_t
atomiciov(ssize_t (* f)(int,const struct iovec *,int),int fd,const struct iovec * _iov,int iovcnt)77 atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
78 const struct iovec *_iov, int iovcnt)
79 {
80 size_t pos = 0, rem;
81 ssize_t res;
82 struct iovec iov_array[IOV_MAX], *iov = iov_array;
83 struct pollfd pfd;
84
85 if (iovcnt > IOV_MAX) {
86 errno = EINVAL;
87 return 0;
88 }
89 /* Make a copy of the iov array because we may modify it below */
90 memcpy(iov, _iov, iovcnt * sizeof(*_iov));
91
92 pfd.fd = fd;
93 pfd.events = f == readv ? POLLIN : POLLOUT;
94 for (; iovcnt > 0 && iov[0].iov_len > 0;) {
95 res = (f) (fd, iov, iovcnt);
96 switch (res) {
97 case -1:
98 if (errno == EINTR)
99 continue;
100 if (errno == EAGAIN) {
101 (void)poll(&pfd, 1, -1);
102 continue;
103 }
104 return 0;
105 case 0:
106 errno = EPIPE;
107 return pos;
108 default:
109 rem = (size_t)res;
110 pos += rem;
111 /* skip completed iov entries */
112 while (iovcnt > 0 && rem >= iov[0].iov_len) {
113 rem -= iov[0].iov_len;
114 iov++;
115 iovcnt--;
116 }
117 /* This shouldn't happen... */
118 if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
119 errno = EFAULT;
120 return 0;
121 }
122 if (iovcnt == 0)
123 break;
124 /* update pointer in partially complete iov */
125 iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
126 iov[0].iov_len -= rem;
127 }
128 }
129 return pos;
130 }
131