atomicio.c (2229B)
1 /* $OpenBSD: atomicio.c,v 1.11 2012/12/04 02:24:47 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 <errno.h> 30 #include <poll.h> 31 #include <unistd.h> 32 33 #include "atomicio.h" 34 35 /* 36 * ensure all of data on socket comes through. f==read || f==vwrite 37 */ 38 size_t 39 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n) 40 { 41 char *s = _s; 42 size_t pos = 0; 43 ssize_t res; 44 struct pollfd pfd; 45 46 pfd.fd = fd; 47 pfd.events = f == read ? POLLIN : POLLOUT; 48 while (n > pos) { 49 res = (f) (fd, s + pos, n - pos); 50 switch (res) { 51 case -1: 52 if (errno == EINTR) 53 continue; 54 if ((errno == EAGAIN) || (errno == ENOBUFS)) { 55 (void)poll(&pfd, 1, -1); 56 continue; 57 } 58 return 0; 59 case 0: 60 errno = EPIPE; 61 return pos; 62 default: 63 pos += (size_t)res; 64 } 65 } 66 return (pos); 67 }