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      1 /*	$NetBSD: atomicio.c,v 1.9 2019/04/20 17:16:40 christos Exp $	*/
      2 /* $OpenBSD: atomicio.c,v 1.30 2019/01/24 02:42:23 dtucker Exp $ */
      3 /*
      4  * Copyright (c) 2006 Damien Miller. All rights reserved.
      5  * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
      6  * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
      7  * All rights reserved.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 #include "includes.h"
     31 __RCSID("$NetBSD: atomicio.c,v 1.9 2019/04/20 17:16:40 christos Exp $");
     32 #include <sys/param.h>
     33 #include <sys/uio.h>
     34 
     35 #include <errno.h>
     36 #include <poll.h>
     37 #include <string.h>
     38 #include <unistd.h>
     39 #include <limits.h>
     40 
     41 #include "atomicio.h"
     42 
     43 /*
     44  * ensure all of data on socket comes through. f==read || f==vwrite
     45  */
     46 size_t
     47 atomicio6(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n,
     48     int (*cb)(void *, size_t), void *cb_arg)
     49 {
     50 	char *s = _s;
     51 	size_t pos = 0;
     52 	ssize_t res;
     53 	struct pollfd pfd;
     54 
     55 	pfd.fd = fd;
     56 	/*
     57 	 * check for vwrite instead of read to avoid read being renamed
     58 	 * by SSP issues
     59 	 */
     60 	pfd.events = f == vwrite ? POLLOUT : POLLIN;
     61 	while (n > pos) {
     62 		res = (f) (fd, s + pos, n - pos);
     63 		switch (res) {
     64 		case -1:
     65 			if (errno == EINTR) {
     66 				/* possible SIGALARM, update callback */
     67 				if (cb != NULL && cb(cb_arg, 0) == -1) {
     68 					errno = EINTR;
     69 					return pos;
     70 				}
     71 				continue;
     72 			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
     73 				(void)poll(&pfd, 1, -1);
     74 				continue;
     75 			}
     76 			return 0;
     77 		case 0:
     78 			errno = EPIPE;
     79 			return pos;
     80 		default:
     81 			pos += (size_t)res;
     82 			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
     83 				errno = EINTR;
     84 				return pos;
     85 			}
     86 		}
     87 	}
     88 	return pos;
     89 }
     90 
     91 size_t
     92 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
     93 {
     94 	return atomicio6(f, fd, _s, n, NULL, NULL);
     95 }
     96 
     97 /*
     98  * ensure all of data on socket comes through. f==readv || f==writev
     99  */
    100 size_t
    101 atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
    102     const struct iovec *_iov, int iovcnt,
    103     int (*cb)(void *, size_t), void *cb_arg)
    104 {
    105 	size_t pos = 0, rem;
    106 	ssize_t res;
    107 	struct iovec iov_array[IOV_MAX], *iov = iov_array;
    108 	struct pollfd pfd;
    109 
    110 	if (iovcnt < 0 || iovcnt > IOV_MAX) {
    111 		errno = EINVAL;
    112 		return 0;
    113 	}
    114 	/* Make a copy of the iov array because we may modify it below */
    115 	memcpy(iov, _iov, (size_t)iovcnt * sizeof(*_iov));
    116 
    117 	pfd.fd = fd;
    118 	pfd.events = f == readv ? POLLIN : POLLOUT;
    119 	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
    120 		res = (f) (fd, iov, iovcnt);
    121 		switch (res) {
    122 		case -1:
    123 			if (errno == EINTR) {
    124 				/* possible SIGALARM, update callback */
    125 				if (cb != NULL && cb(cb_arg, 0) == -1) {
    126 					errno = EINTR;
    127 					return pos;
    128 				}
    129 				continue;
    130 			} else if (errno == EAGAIN || errno == EWOULDBLOCK) {
    131 				(void)poll(&pfd, 1, -1);
    132 				continue;
    133 			}
    134 			return 0;
    135 		case 0:
    136 			errno = EPIPE;
    137 			return pos;
    138 		default:
    139 			rem = (size_t)res;
    140 			pos += rem;
    141 			/* skip completed iov entries */
    142 			while (iovcnt > 0 && rem >= iov[0].iov_len) {
    143 				rem -= iov[0].iov_len;
    144 				iov++;
    145 				iovcnt--;
    146 			}
    147 			/* This shouldn't happen... */
    148 			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
    149 				errno = EFAULT;
    150 				return 0;
    151 			}
    152 			if (iovcnt == 0)
    153 				break;
    154 			/* update pointer in partially complete iov */
    155 			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
    156 			iov[0].iov_len -= rem;
    157 		}
    158 		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
    159 			errno = EINTR;
    160 			return pos;
    161 		}
    162 	}
    163 	return pos;
    164 }
    165 
    166 size_t
    167 atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
    168     const struct iovec *_iov, int iovcnt)
    169 {
    170 	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
    171 }
    172