1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include "namespace.h"
33 #include <stdlib.h>
34 #include <pthread.h>
35 #include <unistd.h>
36 #include "un-namespace.h"
37
38 #include "atexit.h"
39 #include "libc_private.h"
40
41 void (*__cleanup)(void);
42
43 /*
44 * This variable is zero until a process has created a thread.
45 * It is used to avoid calling locking functions in libc when they
46 * are not required. By default, libc is intended to be(come)
47 * thread-safe, but without a (significant) penalty to non-threaded
48 * processes.
49 */
50 int __isthreaded = 0;
51
52 static pthread_mutex_t exit_mutex;
53 static pthread_once_t exit_mutex_once = PTHREAD_ONCE_INIT;
54
55 static void
exit_mutex_init_once(void)56 exit_mutex_init_once(void)
57 {
58 pthread_mutexattr_t ma;
59
60 _pthread_mutexattr_init(&ma);
61 _pthread_mutexattr_settype(&ma, PTHREAD_MUTEX_RECURSIVE);
62 _pthread_mutex_init(&exit_mutex, &ma);
63 _pthread_mutexattr_destroy(&ma);
64 }
65
66 /*
67 * Exit, flushing stdio buffers if necessary.
68 */
69 void
exit(int status)70 exit(int status)
71 {
72 /* Ensure that the auto-initialization routine is linked in: */
73 extern int _thread_autoinit_dummy_decl;
74
75 _thread_autoinit_dummy_decl = 1;
76
77 /* Make exit(3) thread-safe */
78 if (__isthreaded) {
79 _once(&exit_mutex_once, exit_mutex_init_once);
80 _pthread_mutex_lock(&exit_mutex);
81 }
82
83 /*
84 * We're dealing with cleaning up thread_local destructors in the case of
85 * the process termination through main() exit.
86 * Other cases are handled elsewhere.
87 */
88 __cxa_thread_call_dtors();
89 __cxa_finalize(NULL);
90 if (__cleanup)
91 (*__cleanup)();
92 _exit(status);
93 }
94