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atexit.c revision 1.13 
      1 /*	$NetBSD: atexit.c,v 1.13 2003/01/18 11:32:03 thorpej Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Chris Torek.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 #if 0
     42 static char sccsid[] = "@(#)atexit.c	8.2 (Berkeley) 7/3/94";
     43 #else
     44 __RCSID("$NetBSD: atexit.c,v 1.13 2003/01/18 11:32:03 thorpej Exp $");
     45 #endif
     46 #endif /* LIBC_SCCS and not lint */
     47 
     48 #include <assert.h>
     49 #include <errno.h>
     50 #include <stdlib.h>
     51 #include "reentrant.h"
     52 #include "atexit.h"
     53 
     54 struct atexit *__atexit;	/* points to head of LIFO stack */
     55 
     56 #ifdef _REENTRANT
     57 mutex_t __atexit_mutex = MUTEX_INITIALIZER;
     58 #endif
     59 
     60 /*
     61  * Register a function to be performed at exit.
     62  */
     63 int
     64 atexit(fn)
     65 	void (*fn) __P((void));
     66 {
     67 	static struct atexit __atexit0;	/* one guaranteed table */
     68 	struct atexit *p;
     69 
     70 	_DIAGASSERT(fn != NULL);
     71 
     72 	mutex_lock(&__atexit_mutex);
     73 	if ((p = __atexit) == NULL)
     74 		__atexit = p = &__atexit0;
     75 	else if (p->ind >= ATEXIT_SIZE) {
     76 		if ((p = malloc(sizeof(*p))) == NULL) {
     77 			mutex_unlock(&__atexit_mutex);
     78 			return (-1);
     79 		}
     80 		p->ind = 0;
     81 		p->next = __atexit;
     82 		__atexit = p;
     83 	}
     84 	p->fns[p->ind++] = fn;
     85 	mutex_unlock(&__atexit_mutex);
     86 	return (0);
     87 }
     88