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 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 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