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author | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2018-12-27 16:39:27 +0000 |
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committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2018-12-27 16:39:27 +0000 |
commit | 52629237a522c7c146d788ddaaf69946fd2729f9 (patch) | |
tree | 552402b085cff37bc251fc0f45ed9255b53cdd57 /htl/pt-dealloc.c | |
parent | 3896c5809b49e72fbadc57da2189ff42aa2a5d02 (diff) | |
parent | 064374be911f72dfaec8a75f06da1f9fc1827712 (diff) |
Merge commit 'refs/top-bases/t/hurdsig-boot-fix' into t/hurdsig-boot-fix
Diffstat (limited to 'htl/pt-dealloc.c')
-rw-r--r-- | htl/pt-dealloc.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/htl/pt-dealloc.c b/htl/pt-dealloc.c new file mode 100644 index 0000000000..c9a82aa1b9 --- /dev/null +++ b/htl/pt-dealloc.c @@ -0,0 +1,68 @@ +/* Deallocate a thread structure. + Copyright (C) 2000-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <assert.h> +#include <pthread.h> +#include <stdlib.h> + +#include <pt-internal.h> + +#include <atomic.h> + +/* List of thread structures corresponding to free thread IDs. */ +extern struct __pthread *__pthread_free_threads; +extern pthread_mutex_t __pthread_free_threads_lock; + + +/* Deallocate the thread structure for PTHREAD. */ +void +__pthread_dealloc (struct __pthread *pthread) +{ + assert (pthread->state != PTHREAD_TERMINATED); + + if (!atomic_decrement_and_test (&pthread->nr_refs)) + return; + + /* Withdraw this thread from the thread ID lookup table. */ + __pthread_setid (pthread->thread, NULL); + + /* Mark the thread as terminated. We broadcast the condition + here to prevent pthread_join from waiting for this thread to + exit where it was never really started. Such a call to + pthread_join is completely bogus, but unfortunately allowed + by the standards. */ + __pthread_mutex_lock (&pthread->state_lock); + if (pthread->state != PTHREAD_EXITED) + __pthread_cond_broadcast (&pthread->state_cond); + __pthread_mutex_unlock (&pthread->state_lock); + + /* We do not actually deallocate the thread structure, but add it to + a list of re-usable thread structures. */ + __pthread_mutex_lock (&__pthread_free_threads_lock); + __pthread_enqueue (&__pthread_free_threads, pthread); + __pthread_mutex_unlock (&__pthread_free_threads_lock); + + /* Setting PTHREAD->STATE to PTHREAD_TERMINATED makes this TCB + available for reuse. After that point, we can no longer assume + that PTHREAD is valid. + + Note that it is safe to not lock this update to PTHREAD->STATE: + the only way that it can now be accessed is in __pthread_alloc, + which reads this variable. */ + pthread->state = PTHREAD_TERMINATED; +} |