1 /* Thread termination.
2 Copyright (C) 2000-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <assert.h>
20 #include <errno.h>
21 #include <pthread.h>
22 #include <stdlib.h>
23
24 #include <pt-internal.h>
25 #include <pthreadP.h>
26
27 #include <atomic.h>
28
29
30 /* Terminate the current thread and make STATUS available to any
31 thread that might join it. */
32 void
__pthread_exit(void * status)33 __pthread_exit (void *status)
34 {
35 struct __pthread *self = _pthread_self ();
36 struct __pthread_cancelation_handler **handlers;
37 int oldstate;
38
39 /* Run any cancelation handlers. According to POSIX, the
40 cancellation cleanup handlers should be called with cancellation
41 disabled. */
42 __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
43
44 for (handlers = __pthread_get_cleanup_stack ();
45 *handlers != NULL;
46 *handlers = (*handlers)->__next)
47 (*handlers)->__handler ((*handlers)->__arg);
48
49 __pthread_setcancelstate (oldstate, &oldstate);
50
51 /* Decrease the number of threads. We use an atomic operation to
52 make sure that only the last thread calls `exit'. */
53 if (atomic_decrement_and_test (&__pthread_total))
54 /* We are the last thread. */
55 exit (0);
56
57 /* Destroy any thread specific data. */
58 __pthread_destroy_specific (self);
59
60 /* Note that after this point the process can be terminated at any
61 point if another thread calls `pthread_exit' and happens to be
62 the last thread. */
63
64 __pthread_mutex_lock (&self->state_lock);
65
66 if (self->cancel_state == PTHREAD_CANCEL_ENABLE && self->cancel_pending)
67 status = PTHREAD_CANCELED;
68
69 switch (self->state)
70 {
71 default:
72 assert (!"Consistency error: unexpected self->state");
73 abort ();
74 break;
75
76 case PTHREAD_DETACHED:
77 __pthread_mutex_unlock (&self->state_lock);
78
79 break;
80
81 case PTHREAD_JOINABLE:
82 /* We need to stay around for a while since another thread
83 might want to join us. */
84 self->state = PTHREAD_EXITED;
85
86 /* We need to remember the exit status. A thread joining us
87 might ask for it. */
88 self->status = status;
89
90 /* Broadcast the condition. This will wake up threads that are
91 waiting to join us. */
92 __pthread_cond_broadcast (&self->state_cond);
93 __pthread_mutex_unlock (&self->state_lock);
94
95 break;
96 }
97
98 /* Destroy any signal state. */
99 __pthread_sigstate_destroy (self);
100
101 /* Self terminating requires TLS, so defer the release of the TCB until
102 the thread structure is reused. */
103
104 /* Release kernel resources, including the kernel thread and the stack,
105 and drop the self reference. */
106 __pthread_thread_terminate (self);
107
108 /* NOTREACHED */
109 abort ();
110 }
111
112 weak_alias (__pthread_exit, pthread_exit);
113