1/* Wait for 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 <errno.h>
20#include <pthread.h>
21#include <stddef.h>
22
23#include <pt-internal.h>
24
25/* Make calling thread wait for termination of thread THREAD. Return
26 the exit status of the thread in *STATUS. */
27static int
28__pthread_join_common (pthread_t thread, void **status, int try,
29 clockid_t clockid,
30 const struct timespec *abstime)
31{
32 struct __pthread *pthread;
33 int err = 0;
34
35 /* Lookup the thread structure for THREAD. */
36 pthread = __pthread_getid (thread);
37 if (pthread == NULL)
38 return ESRCH;
39
40 if (pthread == _pthread_self ())
41 return EDEADLK;
42
43 __pthread_mutex_lock (&pthread->state_lock);
44
45 if (try == 0)
46 {
47 pthread_cleanup_push ((void (*)(void *)) __pthread_mutex_unlock,
48 &pthread->state_lock);
49
50 /* Rely on pthread_cond_wait being a cancellation point to make
51 pthread_join one too. */
52 while (pthread->state == PTHREAD_JOINABLE && err != ETIMEDOUT)
53 err = __pthread_cond_clockwait (&pthread->state_cond,
54 &pthread->state_lock,
55 clockid, abstime);
56
57 pthread_cleanup_pop (0);
58 }
59
60 switch (pthread->state)
61 {
62 case PTHREAD_JOINABLE:
63 __pthread_mutex_unlock (&pthread->state_lock);
64 if (err != ETIMEDOUT)
65 err = EBUSY;
66 break;
67
68 case PTHREAD_EXITED:
69 /* THREAD has already exited. Salvage its exit status. */
70 if (status != NULL)
71 *status = pthread->status;
72
73 __pthread_mutex_unlock (&pthread->state_lock);
74
75 __pthread_dealloc (thread: pthread);
76 break;
77
78 default:
79 /* Thou shalt not join non-joinable threads! */
80 __pthread_mutex_unlock (&pthread->state_lock);
81 err = EINVAL;
82 break;
83 }
84
85 return err;
86}
87
88int
89__pthread_join (pthread_t thread, void **status)
90{
91 return __pthread_join_common (thread, status, try: 0, CLOCK_REALTIME, NULL);
92}
93weak_alias (__pthread_join, pthread_join);
94
95int
96__pthread_tryjoin_np (pthread_t thread, void **status)
97{
98 return __pthread_join_common (thread, status, try: 1, CLOCK_REALTIME, NULL);
99}
100weak_alias (__pthread_tryjoin_np, pthread_tryjoin_np);
101
102int
103__pthread_timedjoin_np (pthread_t thread, void **status,
104 const struct timespec *abstime)
105{
106 return __pthread_join_common (thread, status, try: 0, CLOCK_REALTIME, abstime);
107}
108weak_alias (__pthread_timedjoin_np, pthread_timedjoin_np);
109
110int
111__pthread_clockjoin_np (pthread_t thread, void **status,
112 clockid_t clockid,
113 const struct timespec *abstime)
114{
115 return __pthread_join_common (thread, status, try: 0, clockid, abstime);
116}
117weak_alias (__pthread_clockjoin_np, pthread_clockjoin_np);
118

source code of glibc/htl/pt-join.c