projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 33574c17 | 1 | /* Deallocate a thread structure. |
| 04277e02 | 2 | Copyright (C) 2000-2019 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 | |
| 17 | <http://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 | } |