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ec216c2634
Change the FILE locking to support kernel threads when linked with libpthread (which you haven't see yet). This requires that libc become thread-safe and thread-aware, testing __isthreaded before attempting to do lock/unlock calls. The impact on non-threaded programs is minor. This change works with libc_r, so it's the best compromise.
75 lines
2.6 KiB
C
75 lines
2.6 KiB
C
/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)fpurge.c 8.1 (Berkeley) 6/4/93";
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#endif
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static const char rcsid[] =
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"$Id: fpurge.c,v 1.5 1997/02/22 15:01:58 peter Exp $";
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#endif /* LIBC_SCCS and not lint */
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "local.h"
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#include "libc_private.h"
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/*
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* fpurge: like fflush, but without writing anything: leave the
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* given FILE's buffer empty.
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*/
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int
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fpurge(fp)
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register FILE *fp;
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{
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int retval;
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FLOCKFILE(fp);
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if (!fp->_flags) {
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errno = EBADF;
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retval = EOF;
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} else {
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if (HASUB(fp))
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FREEUB(fp);
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fp->_p = fp->_bf._base;
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fp->_r = 0;
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fp->_w = fp->_flags & (__SLBF|__SNBF) ? 0 : fp->_bf._size;
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retval = 0;
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}
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FUNLOCKFILE(fp);
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return (retval);
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}
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