| 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 |  |  | } |