100 lines
2.8 KiB
C
100 lines
2.8 KiB
C
/*
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* CDE - Common Desktop Environment
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*
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* Copyright (c) 1993-2012, The Open Group. All rights reserved.
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*
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* These libraries and programs are free software; you can
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* redistribute them and/or modify them under the terms of the GNU
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* Lesser General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* These libraries and programs are distributed in the hope that
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* they will be useful, but WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU Lesser General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with these libraries and programs; if not, write
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* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
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* Floor, Boston, MA 02110-1301 USA
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*/
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/*
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* $XConsortium: atomic_lock.C /main/4 1996/11/01 10:19:09 drk $
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*
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* Copyright (c) 1993 HAL Computer Systems International, Ltd.
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* All rights reserved. Unpublished -- rights reserved under
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* the Copyright Laws of the United States. USE OF A COPYRIGHT
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* NOTICE IS PRECAUTIONARY ONLY AND DOES NOT IMPLY PUBLICATION
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* OR DISCLOSURE.
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*
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* THIS SOFTWARE CONTAINS CONFIDENTIAL INFORMATION AND TRADE
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* SECRETS OF HAL COMPUTER SYSTEMS INTERNATIONAL, LTD. USE,
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* DISCLOSURE, OR REPRODUCTION IS PROHIBITED WITHOUT THE
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* PRIOR EXPRESS WRITTEN PERMISSION OF HAL COMPUTER SYSTEMS
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* INTERNATIONAL, LTD.
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*
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* RESTRICTED RIGHTS LEGEND
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* Use, duplication, or disclosure by the Government is subject
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* to the restrictions as set forth in subparagraph (c)(l)(ii)
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* of the Rights in Technical Data and Computer Software clause
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* at DFARS 252.227-7013.
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*
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* HAL COMPUTER SYSTEMS INTERNATIONAL, LTD.
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* 1315 Dell Avenue
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* Campbell, CA 95008
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*
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*/
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#include "atomic_lock.h"
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#include <X11/Xosdefs.h>
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#include <errno.h>
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#ifdef X_NOT_STDC_ENV
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extern int errno;
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#endif
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atomic_lock::atomic_lock(const char* p)
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{
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int len = MIN(strlen(p), PATHSIZ - 1);
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*((char *) memcpy(v_path, p, len) + len) = '\0';
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}
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atomic_lock::~atomic_lock()
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{
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}
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/////////////////////////////////////////
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// from Rochkind's Adv. UNIX programming
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/////////////////////////////////////////
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Boolean atomic_lock::lock()
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{
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int fd, tries;
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tries = 0;
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while ( (fd = creat(v_path, 0)) == -1 && errno == EACCES ) {
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if ( ++tries >= MAXTRIES )
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break;
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sleep (NAPTIME);
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}
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if ( fd == -1 || close(fd) == -1 ) {
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perror("lock");
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return false;
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} else
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return true;
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}
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Boolean atomic_lock::unlock()
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{
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if ( unlink(v_path) == -1 ) {
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MESSAGE(cerr, "unlock(): unlink() failed");
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throw(systemException(errno));
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}
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return true;
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}
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