97 lines
3.6 KiB
C
97 lines
3.6 KiB
C
/* $NetBSD: read.c,v 1.8 1997/01/22 00:38:12 cgd Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* The Mach Operating System project at Carnegie-Mellon University.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* @(#)read.c 8.1 (Berkeley) 6/11/93
|
|
*
|
|
*
|
|
* Copyright (c) 1989, 1990, 1991 Carnegie Mellon University
|
|
* All Rights Reserved.
|
|
*
|
|
* Author: Alessandro Forin
|
|
*
|
|
* Permission to use, copy, modify and distribute this software and its
|
|
* documentation is hereby granted, provided that both the copyright
|
|
* notice and this permission notice appear in all copies of the
|
|
* software, derivative works or modified versions, and any portions
|
|
* thereof, and that both notices appear in supporting documentation.
|
|
*
|
|
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
|
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
|
|
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
|
*
|
|
* Carnegie Mellon requests users of this software to return to
|
|
*
|
|
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
|
* School of Computer Science
|
|
* Carnegie Mellon University
|
|
* Pittsburgh PA 15213-3890
|
|
*
|
|
* any improvements or extensions that they make and grant Carnegie the
|
|
* rights to redistribute these changes.
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include "stand.h"
|
|
|
|
ssize_t
|
|
read(fd, dest, bcount)
|
|
int fd;
|
|
void *dest;
|
|
size_t bcount;
|
|
{
|
|
register struct open_file *f = &files[fd];
|
|
size_t resid;
|
|
|
|
if ((unsigned)fd >= SOPEN_MAX || !(f->f_flags & F_READ)) {
|
|
errno = EBADF;
|
|
return (-1);
|
|
}
|
|
if (f->f_flags & F_RAW) {
|
|
twiddle();
|
|
errno = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
|
|
btodb(f->f_offset), bcount, dest, &resid);
|
|
if (errno)
|
|
return (-1);
|
|
f->f_offset += resid;
|
|
return (resid);
|
|
}
|
|
resid = bcount;
|
|
if ((errno = (f->f_ops->fo_read)(f, dest, bcount, &resid)))
|
|
return (-1);
|
|
return (ssize_t)(bcount - resid);
|
|
}
|