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 "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 45 #include "atomicio.h" 46 47 /* 48 * ensure all of data on socket comes through. f==read || f==vwrite 49 */ 50 size_t 51 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n) 52 { 53 char *s = _s; 54 size_t pos = 0; 55 ssize_t res; 56 struct pollfd pfd; 57 58 pfd.fd = fd; 59 pfd.events = f == read ? POLLIN : POLLOUT; 60 while (n > pos) { 61 res = (f) (fd, s + pos, n - pos); 62 switch (res) { 63 case -1: 64 if (errno == EINTR) 65 continue; 66 if (errno == EAGAIN || errno == EWOULDBLOCK) { 67 (void)poll(&pfd, 1, -1); 68 continue; 69 } 70 return 0; 71 case 0: 72 errno = EPIPE; 73 return pos; 74 default: 75 pos += (size_t)res; 76 } 77 } 78 return (pos); 79 } 80 81 /* 82 * ensure all of data on socket comes through. f==readv || f==writev 83 */ 84 size_t 85 atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd, 86 const struct iovec *_iov, int iovcnt) 87 { 88 size_t pos = 0, rem; 89 ssize_t res; 90 struct iovec iov_array[IOV_MAX], *iov = iov_array; 91 struct pollfd pfd; 92 93 if (iovcnt > IOV_MAX) { 94 errno = EINVAL; 95 return 0; 96 } 97 /* Make a copy of the iov array because we may modify it below */ 98 memcpy(iov, _iov, iovcnt * sizeof(*_iov)); 99 100 #ifndef BROKEN_READV_COMPARISON 101 pfd.fd = fd; 102 pfd.events = f == readv ? POLLIN : POLLOUT; 103 #endif 104 for (; iovcnt > 0 && iov[0].iov_len > 0;) { 105 res = (f) (fd, iov, iovcnt); 106 switch (res) { 107 case -1: 108 if (errno == EINTR) 109 continue; 110 if (errno == EAGAIN || errno == EWOULDBLOCK) { 111 #ifndef BROKEN_READV_COMPARISON 112 (void)poll(&pfd, 1, -1); 113 #endif 114 continue; 115 } 116 return 0; 117 case 0: 118 errno = EPIPE; 119 return pos; 120 default: 121 rem = (size_t)res; 122 pos += rem; 123 /* skip completed iov entries */ 124 while (iovcnt > 0 && rem >= iov[0].iov_len) { 125 rem -= iov[0].iov_len; 126 iov++; 127 iovcnt--; 128 } 129 /* This shouldn't happen... */ 130 if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) { 131 errno = EFAULT; 132 return 0; 133 } 134 if (iovcnt == 0) 135 break; 136 /* update pointer in partially complete iov */ 137 iov[0].iov_base = ((char *)iov[0].iov_base) + rem; 138 iov[0].iov_len -= rem; 139 } 140 } 141 return pos; 142 } 143