97df383415
by switching into single-thread mode. libthr ignores broken use of lock bitmaps used by default rtld locking implementation, this in turn turns lock handoff in _rtld_thread_init into NOP. This in turn makes child processes of forked multi-threaded programs to run with _thr_signal_block still in effect, with most signals blocked. Reported by: phk, kib
209 lines
6.1 KiB
C
209 lines
6.1 KiB
C
/*
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* Copyright (c) 2005 David Xu <davidxu@freebsd.org>
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* Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include "namespace.h"
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <spinlock.h>
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#include "un-namespace.h"
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#include "libc_private.h"
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#include "rtld_lock.h"
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#include "thr_private.h"
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__weak_reference(_pthread_atfork, pthread_atfork);
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int
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_pthread_atfork(void (*prepare)(void), void (*parent)(void),
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void (*child)(void))
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{
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struct pthread *curthread;
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struct pthread_atfork *af;
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_thr_check_init();
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if ((af = malloc(sizeof(struct pthread_atfork))) == NULL)
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return (ENOMEM);
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curthread = _get_curthread();
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af->prepare = prepare;
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af->parent = parent;
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af->child = child;
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THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock);
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TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe);
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THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock);
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return (0);
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}
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__weak_reference(_fork, fork);
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pid_t _fork(void);
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pid_t
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_fork(void)
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{
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struct pthread *curthread;
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struct pthread_atfork *af;
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pid_t ret;
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int errsave;
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int unlock_malloc;
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int rtld_locks[16];
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if (!_thr_is_inited())
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return (__sys_fork());
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curthread = _get_curthread();
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THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock);
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/* Run down atfork prepare handlers. */
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TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) {
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if (af->prepare != NULL)
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af->prepare();
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}
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/*
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* Try our best to protect memory from being corrupted in
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* child process because another thread in malloc code will
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* simply be kill by fork().
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*/
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if (_thr_isthreaded() != 0) {
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unlock_malloc = 1;
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_malloc_prefork();
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_rtld_atfork_pre(rtld_locks);
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} else {
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unlock_malloc = 0;
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}
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/*
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* Block all signals until we reach a safe point.
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*/
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_thr_signal_block(curthread);
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/* Fork a new process: */
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if ((ret = __sys_fork()) == 0) {
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/* Child process */
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errsave = errno;
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curthread->cancel_pending = 0;
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curthread->flags &= ~THR_FLAGS_NEED_SUSPEND;
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/*
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* Thread list will be reinitialized, and later we call
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* _libpthread_init(), it will add us back to list.
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*/
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curthread->tlflags &= ~(TLFLAGS_IN_TDLIST | TLFLAGS_DETACHED);
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/* child is a new kernel thread. */
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thr_self(&curthread->tid);
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/* clear other threads locked us. */
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_thr_umutex_init(&curthread->lock);
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_thr_umutex_init(&_thr_atfork_lock);
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if (unlock_malloc)
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_rtld_atfork_post(rtld_locks);
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_thr_setthreaded(0);
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/* reinitialize libc spinlocks. */
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_thr_spinlock_init();
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_mutex_fork(curthread);
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/* reinitalize library. */
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_libpthread_init(curthread);
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/* Ready to continue, unblock signals. */
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_thr_signal_unblock(curthread);
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if (unlock_malloc)
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_malloc_postfork();
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/* Run down atfork child handlers. */
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TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
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if (af->child != NULL)
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af->child();
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}
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} else {
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/* Parent process */
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errsave = errno;
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/* Ready to continue, unblock signals. */
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_thr_signal_unblock(curthread);
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if (unlock_malloc) {
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_rtld_atfork_post(rtld_locks);
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_malloc_postfork();
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}
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/* Run down atfork parent handlers. */
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TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
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if (af->parent != NULL)
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af->parent();
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}
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THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock);
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}
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errno = errsave;
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/* Return the process ID: */
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return (ret);
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}
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