diff options
Diffstat (limited to 'nptl/unregister-atfork.c')
| -rw-r--r-- | nptl/unregister-atfork.c | 121 |
1 files changed, 0 insertions, 121 deletions
diff --git a/nptl/unregister-atfork.c b/nptl/unregister-atfork.c deleted file mode 100644 index 1eb11d60c6..0000000000 --- a/nptl/unregister-atfork.c +++ /dev/null @@ -1,121 +0,0 @@ -/* Copyright (C) 2002-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. - - 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 <errno.h> -#include <stdlib.h> -#include <fork.h> -#include <atomic.h> -#include <futex-internal.h> - - -void -__unregister_atfork (void *dso_handle) -{ - /* Check whether there is any entry in the list which we have to - remove. It is likely that this is not the case so don't bother - getting the lock. - - We do not worry about other threads adding entries for this DSO - right this moment. If this happens this is a race and we can do - whatever we please. The program will crash anyway seen. */ - struct fork_handler *runp = __fork_handlers; - struct fork_handler *lastp = NULL; - - while (runp != NULL) - if (runp->dso_handle == dso_handle) - break; - else - { - lastp = runp; - runp = runp->next; - } - - if (runp == NULL) - /* Nothing to do. */ - return; - - /* Get the lock to not conflict with additions or deletions. Note - that there couldn't have been another thread deleting something. - The __unregister_atfork function is only called from the - dlclose() code which itself serializes the operations. */ - lll_lock (__fork_lock, LLL_PRIVATE); - - /* We have to create a new list with all the entries we don't remove. */ - struct deleted_handler - { - struct fork_handler *handler; - struct deleted_handler *next; - } *deleted = NULL; - - /* Remove the entries for the DSO which is unloaded from the list. - It's a single linked list so readers are. */ - do - { - again: - if (runp->dso_handle == dso_handle) - { - if (lastp == NULL) - { - /* We have to use an atomic operation here because - __linkin_atfork also uses one. */ - if (catomic_compare_and_exchange_bool_acq (&__fork_handlers, - runp->next, runp) - != 0) - { - runp = __fork_handlers; - goto again; - } - } - else - lastp->next = runp->next; - - /* We cannot overwrite the ->next element now. Put the deleted - entries in a separate list. */ - struct deleted_handler *newp = alloca (sizeof (*newp)); - newp->handler = runp; - newp->next = deleted; - deleted = newp; - } - else - lastp = runp; - - runp = runp->next; - } - while (runp != NULL); - - /* Release the lock. */ - lll_unlock (__fork_lock, LLL_PRIVATE); - - /* Walk the list of all entries which have to be deleted. */ - while (deleted != NULL) - { - /* We need to be informed by possible current users. */ - deleted->handler->need_signal = 1; - /* Make sure this gets written out first. */ - atomic_write_barrier (); - - /* Decrement the reference counter. If it does not reach zero - wait for the last user. */ - atomic_decrement (&deleted->handler->refcntr); - unsigned int val; - while ((val = deleted->handler->refcntr) != 0) - futex_wait_simple (&deleted->handler->refcntr, val, FUTEX_PRIVATE); - - deleted = deleted->next; - } -} |