Libc-320.tar.gz

[apple/libc.git] / stdlib / FreeBSD / atexit.c

diff --git a/stdlib/FreeBSD/atexit.c b/stdlib/FreeBSD/atexit.c
new file mode 100644 (file)
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--- /dev/null
+++ b/stdlib/FreeBSD/atexit.c
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+/*-
+ * Copyright (c) 1990, 1993
+ *     The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)atexit.c   8.2 (Berkeley) 7/3/94";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: src/lib/libc/stdlib/atexit.c,v 1.6 2002/03/22 21:53:09 obrien Exp $");
+
+#include "namespace.h"
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <pthread.h>
+#include "atexit.h"
+#include "un-namespace.h"
+
+#include "libc_private.h"
+
+static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+#define _MUTEX_LOCK(x)         if (__isthreaded) _pthread_mutex_lock(x)
+#define _MUTEX_UNLOCK(x)       if (__isthreaded) _pthread_mutex_unlock(x)
+
+struct atexit *__atexit;       /* points to head of LIFO stack */
+
+/*
+ * Register a function to be performed at exit.
+ */
+int
+atexit(fn)
+       void (*fn)();
+{
+       static struct atexit __atexit0; /* one guaranteed table */
+       struct atexit *p;
+
+       _MUTEX_LOCK(&atexit_mutex);
+       if ((p = __atexit) == NULL)
+               __atexit = p = &__atexit0;
+       else while (p->ind >= ATEXIT_SIZE) {
+               struct atexit *old__atexit;
+               old__atexit = __atexit;
+               _MUTEX_UNLOCK(&atexit_mutex);
+               if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL)
+                       return (-1);
+               _MUTEX_LOCK(&atexit_mutex);
+               if (old__atexit != __atexit) {
+                       /* Lost race, retry operation */
+                       _MUTEX_UNLOCK(&atexit_mutex);
+                       free(p);
+                       _MUTEX_LOCK(&atexit_mutex);
+                       p = __atexit;
+                       continue;
+               }
+               p->ind = 0;
+               p->next = __atexit;
+               __atexit = p;
+       }
+       p->fns[p->ind++] = fn;
+       _MUTEX_UNLOCK(&atexit_mutex);
+       return (0);
+}