70 lines
2.1 KiB
C
70 lines
2.1 KiB
C
#ident "$Id: opendev.c,v 1.3 2004/11/23 23:43:02 hpa Exp $"
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/* ----------------------------------------------------------------------- *
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*
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* Copyright 2003-2004 H. Peter Anvin - All Rights Reserved
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom
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* the Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall
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* be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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* ----------------------------------------------------------------------- */
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#include <errno.h>
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#include <com32.h>
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#include <string.h>
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#include "file.h"
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/*
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* opendev.c
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*
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* Open a special device
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*/
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int opendev(const struct input_dev *idev, const struct output_dev *odev, int flags)
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{
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int fd;
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struct file_info *fp;
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int okflags;
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okflags = (idev ? idev->fileflags : 0) | (odev ? odev->fileflags : 0);
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if ( !(flags & 3) || (flags & ~okflags) ) {
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errno = EINVAL;
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return -1;
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}
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for ( fd = 0, fp = __file_info ; fd < NFILES ; fd++, fp++ )
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if ( !fp->iop && !fp->oop )
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break;
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if ( fd >= NFILES ) {
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errno = EMFILE;
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return -1;
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}
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fp->iop = idev ? idev : &dev_error_r;
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fp->oop = odev ? odev : &dev_error_w;
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fp->i.offset = 0;
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fp->i.nbytes = 0;
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fp->i.datap = fp->i.buf;
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return fd;
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}
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