atexit.c revision 91697
11573Srgrimes/*- 21573Srgrimes * Copyright (c) 1990, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * This code is derived from software contributed to Berkeley by 61573Srgrimes * Chris Torek. 71573Srgrimes * 81573Srgrimes * Redistribution and use in source and binary forms, with or without 91573Srgrimes * modification, are permitted provided that the following conditions 101573Srgrimes * are met: 111573Srgrimes * 1. Redistributions of source code must retain the above copyright 121573Srgrimes * notice, this list of conditions and the following disclaimer. 131573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer in the 151573Srgrimes * documentation and/or other materials provided with the distribution. 161573Srgrimes * 3. All advertising materials mentioning features or use of this software 171573Srgrimes * must display the following acknowledgement: 181573Srgrimes * This product includes software developed by the University of 191573Srgrimes * California, Berkeley and its contributors. 201573Srgrimes * 4. Neither the name of the University nor the names of its contributors 211573Srgrimes * may be used to endorse or promote products derived from this software 221573Srgrimes * without specific prior written permission. 231573Srgrimes * 241573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 251573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 261573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 271573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 281573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 291573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 301573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 311573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 321573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 331573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 341573Srgrimes * SUCH DAMAGE. 3591697Stegge * 3691697Stegge * $FreeBSD: head/lib/libc/stdlib/atexit.c 91697 2002-03-05 17:34:37Z tegge $ 371573Srgrimes */ 381573Srgrimes 391573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 4023662Speterstatic char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94"; 411573Srgrimes#endif /* LIBC_SCCS and not lint */ 421573Srgrimes 4391697Stegge#include "namespace.h" 441573Srgrimes#include <stddef.h> 451573Srgrimes#include <stdlib.h> 4618516Sphk#include <unistd.h> 4791697Stegge#include <pthread.h> 481573Srgrimes#include "atexit.h" 4991697Stegge#include "un-namespace.h" 501573Srgrimes 5191697Stegge#include "libc_private.h" 5291697Stegge 5391697Steggestatic pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; 5491697Stegge 5591697Stegge#define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) 5691697Stegge#define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) 5791697Stegge 5823662Speterstruct atexit *__atexit; /* points to head of LIFO stack */ 5923662Speter 601573Srgrimes/* 611573Srgrimes * Register a function to be performed at exit. 621573Srgrimes */ 631573Srgrimesint 641573Srgrimesatexit(fn) 651573Srgrimes void (*fn)(); 661573Srgrimes{ 671573Srgrimes static struct atexit __atexit0; /* one guaranteed table */ 681573Srgrimes register struct atexit *p; 691573Srgrimes 7091697Stegge _MUTEX_LOCK(&atexit_mutex); 711573Srgrimes if ((p = __atexit) == NULL) 721573Srgrimes __atexit = p = &__atexit0; 7391697Stegge else while (p->ind >= ATEXIT_SIZE) { 7491697Stegge struct atexit *old__atexit; 7591697Stegge old__atexit = __atexit; 7691697Stegge _MUTEX_UNLOCK(&atexit_mutex); 7791697Stegge if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 781573Srgrimes return (-1); 7991697Stegge _MUTEX_LOCK(&atexit_mutex); 8091697Stegge if (old__atexit != __atexit) { 8191697Stegge /* Lost race, retry operation */ 8291697Stegge _MUTEX_UNLOCK(&atexit_mutex); 8391697Stegge free(p); 8491697Stegge _MUTEX_LOCK(&atexit_mutex); 8591697Stegge p = __atexit; 8691697Stegge continue; 8791697Stegge } 881573Srgrimes p->ind = 0; 891573Srgrimes p->next = __atexit; 901573Srgrimes __atexit = p; 911573Srgrimes } 921573Srgrimes p->fns[p->ind++] = fn; 9391697Stegge _MUTEX_UNLOCK(&atexit_mutex); 941573Srgrimes return (0); 951573Srgrimes} 96