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 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 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