]>
Commit | Line | Data |
---|---|---|
33574c17 | 1 | /* Deallocate a thread structure. |
d614a753 | 2 | Copyright (C) 2000-2020 Free Software Foundation, Inc. |
33574c17 ST |
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 | |
ad2b41bf ST |
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. | |
33574c17 ST |
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 | |
ad2b41bf | 13 | Lesser General Public License for more details. |
33574c17 | 14 | |
ad2b41bf ST |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
33574c17 ST |
18 | |
19 | #include <assert.h> | |
20 | #include <pthread.h> | |
21 | #include <stdlib.h> | |
22 | ||
23 | #include <pt-internal.h> | |
24 | ||
25 | #include <atomic.h> | |
26 | ||
27 | /* List of thread structures corresponding to free thread IDs. */ | |
28 | extern struct __pthread *__pthread_free_threads; | |
29 | extern pthread_mutex_t __pthread_free_threads_lock; | |
30 | ||
31 | ||
32 | /* Deallocate the thread structure for PTHREAD. */ | |
33 | void | |
34 | __pthread_dealloc (struct __pthread *pthread) | |
35 | { | |
36 | assert (pthread->state != PTHREAD_TERMINATED); | |
37 | ||
38 | if (!atomic_decrement_and_test (&pthread->nr_refs)) | |
39 | return; | |
40 | ||
41 | /* Withdraw this thread from the thread ID lookup table. */ | |
42 | __pthread_setid (pthread->thread, NULL); | |
43 | ||
44 | /* Mark the thread as terminated. We broadcast the condition | |
45 | here to prevent pthread_join from waiting for this thread to | |
46 | exit where it was never really started. Such a call to | |
47 | pthread_join is completely bogus, but unfortunately allowed | |
48 | by the standards. */ | |
49 | __pthread_mutex_lock (&pthread->state_lock); | |
50 | if (pthread->state != PTHREAD_EXITED) | |
51 | __pthread_cond_broadcast (&pthread->state_cond); | |
52 | __pthread_mutex_unlock (&pthread->state_lock); | |
53 | ||
54 | /* We do not actually deallocate the thread structure, but add it to | |
55 | a list of re-usable thread structures. */ | |
56 | __pthread_mutex_lock (&__pthread_free_threads_lock); | |
57 | __pthread_enqueue (&__pthread_free_threads, pthread); | |
58 | __pthread_mutex_unlock (&__pthread_free_threads_lock); | |
59 | ||
60 | /* Setting PTHREAD->STATE to PTHREAD_TERMINATED makes this TCB | |
61 | available for reuse. After that point, we can no longer assume | |
62 | that PTHREAD is valid. | |
63 | ||
64 | Note that it is safe to not lock this update to PTHREAD->STATE: | |
65 | the only way that it can now be accessed is in __pthread_alloc, | |
66 | which reads this variable. */ | |
67 | pthread->state = PTHREAD_TERMINATED; | |
68 | } |