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      1 /* $OpenBSD: atomicio.c,v 1.26 2010/09/22 22:58:51 djm 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 atomicio6(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n,
     52     int (*cb)(void *, size_t), void *cb_arg)
     53 {
     54 	char *s = _s;
     55 	size_t pos = 0;
     56 	ssize_t res;
     57 	struct pollfd pfd;
     58 
     59 	pfd.fd = fd;
     60 	pfd.events = f == read ? POLLIN : POLLOUT;
     61 	while (n > pos) {
     62 		res = (f) (fd, s + pos, n - pos);
     63 		switch (res) {
     64 		case -1:
     65 			if (errno == EINTR)
     66 				continue;
     67 			if (errno == EAGAIN || errno == EWOULDBLOCK) {
     68 				(void)poll(&pfd, 1, -1);
     69 				continue;
     70 			}
     71 			return 0;
     72 		case 0:
     73 			errno = EPIPE;
     74 			return pos;
     75 		default:
     76 			pos += (size_t)res;
     77 			if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
     78 				errno = EINTR;
     79 				return pos;
     80 			}
     81 		}
     82 	}
     83 	return pos;
     84 }
     85 
     86 size_t
     87 atomicio(ssize_t (*f) (int, void *, size_t), int fd, void *_s, size_t n)
     88 {
     89 	return atomicio6(f, fd, _s, n, NULL, NULL);
     90 }
     91 
     92 /*
     93  * ensure all of data on socket comes through. f==readv || f==writev
     94  */
     95 size_t
     96 atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
     97     const struct iovec *_iov, int iovcnt,
     98     int (*cb)(void *, size_t), void *cb_arg)
     99 {
    100 	size_t pos = 0, rem;
    101 	ssize_t res;
    102 	struct iovec iov_array[IOV_MAX], *iov = iov_array;
    103 	struct pollfd pfd;
    104 
    105 	if (iovcnt > IOV_MAX) {
    106 		errno = EINVAL;
    107 		return 0;
    108 	}
    109 	/* Make a copy of the iov array because we may modify it below */
    110 	memcpy(iov, _iov, iovcnt * sizeof(*_iov));
    111 
    112 #ifndef BROKEN_READV_COMPARISON
    113 	pfd.fd = fd;
    114 	pfd.events = f == readv ? POLLIN : POLLOUT;
    115 #endif
    116 	for (; iovcnt > 0 && iov[0].iov_len > 0;) {
    117 		res = (f) (fd, iov, iovcnt);
    118 		switch (res) {
    119 		case -1:
    120 			if (errno == EINTR)
    121 				continue;
    122 			if (errno == EAGAIN || errno == EWOULDBLOCK) {
    123 #ifndef BROKEN_READV_COMPARISON
    124 				(void)poll(&pfd, 1, -1);
    125 #endif
    126 				continue;
    127 			}
    128 			return 0;
    129 		case 0:
    130 			errno = EPIPE;
    131 			return pos;
    132 		default:
    133 			rem = (size_t)res;
    134 			pos += rem;
    135 			/* skip completed iov entries */
    136 			while (iovcnt > 0 && rem >= iov[0].iov_len) {
    137 				rem -= iov[0].iov_len;
    138 				iov++;
    139 				iovcnt--;
    140 			}
    141 			/* This shouldn't happen... */
    142 			if (rem > 0 && (iovcnt <= 0 || rem > iov[0].iov_len)) {
    143 				errno = EFAULT;
    144 				return 0;
    145 			}
    146 			if (iovcnt == 0)
    147 				break;
    148 			/* update pointer in partially complete iov */
    149 			iov[0].iov_base = ((char *)iov[0].iov_base) + rem;
    150 			iov[0].iov_len -= rem;
    151 		}
    152 		if (cb != NULL && cb(cb_arg, (size_t)res) == -1) {
    153 			errno = EINTR;
    154 			return pos;
    155 		}
    156 	}
    157 	return pos;
    158 }
    159 
    160 size_t
    161 atomiciov(ssize_t (*f) (int, const struct iovec *, int), int fd,
    162     const struct iovec *_iov, int iovcnt)
    163 {
    164 	return atomiciov6(f, fd, _iov, iovcnt, NULL, NULL);
    165 }
    166