1 files changed, 93 insertions, 0 deletions
diff --git a/lib/libc/stdlib/exit.c b/lib/libc/stdlib/exit.c
new file mode 100644
index 000000000000..16631fad5b90
--- /dev/null
+++ b/lib/libc/stdlib/exit.c
@@ -0,0 +1,93 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * 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. 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.
+ */
+
+#include "namespace.h"
+#include <stdlib.h>
+#include <pthread.h>
+#include <unistd.h>
+#include "un-namespace.h"
+
+#include "atexit.h"
+#include "libc_private.h"
+
+void (*__cleanup)(void);
+
+/*
+ * This variable is zero until a process has created a thread.
+ * It is used to avoid calling locking functions in libc when they
+ * are not required. By default, libc is intended to be(come)
+ * thread-safe, but without a (significant) penalty to non-threaded
+ * processes.
+ */
+int	__isthreaded	= 0;
+
+static pthread_mutex_t exit_mutex;
+static pthread_once_t exit_mutex_once = PTHREAD_ONCE_INIT;
+
+static void
+exit_mutex_init_once(void)
+{
+	pthread_mutexattr_t ma;
+
+	_pthread_mutexattr_init(&ma);
+	_pthread_mutexattr_settype(&ma, PTHREAD_MUTEX_RECURSIVE);
+	_pthread_mutex_init(&exit_mutex, &ma);
+	_pthread_mutexattr_destroy(&ma);
+}
+
+/*
+ * Exit, flushing stdio buffers if necessary.
+ */
+void
+exit(int status)
+{
+	/* Ensure that the auto-initialization routine is linked in: */
+	extern int _thread_autoinit_dummy_decl;
+
+	_thread_autoinit_dummy_decl = 1;
+
+	/* Make exit(3) thread-safe */
+	if (__isthreaded) {
+		_once(&exit_mutex_once, exit_mutex_init_once);
+		_pthread_mutex_lock(&exit_mutex);
+	}
+
+	/*
+	 * We're dealing with cleaning up thread_local destructors in the case of
+	 * the process termination through main() exit.
+	 * Other cases are handled elsewhere.
+	 */
+	__cxa_thread_call_dtors();
+	__cxa_finalize(NULL);
+	if (__cleanup)
+		(*__cleanup)();
+	_exit(status);
+}