71 lines
2 KiB
C
71 lines
2 KiB
C
/* $NetBSD: pread.c,v 1.7 2008/12/14 17:03:43 christos Exp $ */
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/*
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* Copyright (c) 1996
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* Matthias Drochner. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/* read into destination in flat addr space */
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#include <lib/libsa/stand.h>
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#include "libi386.h"
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#ifdef SAVE_MEMORY
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#define BUFSIZE (1*1024)
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#else
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#define BUFSIZE (4*1024)
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#endif
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static char *buf;
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ssize_t
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pread(int fd, void *dest, size_t size)
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{
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int rsize;
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if (!buf)
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buf = alloc(BUFSIZE);
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rsize = size;
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while (rsize > 0) {
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int count, got;
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count = (rsize < BUFSIZE ? rsize : BUFSIZE);
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got = read(fd, buf, count);
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if (got < 0)
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return -1;
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/* put to physical space */
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vpbcopy(buf, dest, got);
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dest += got;
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rsize -= got;
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if (got < count)
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break; /* EOF */
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}
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return size - rsize;
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}
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