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04277e02d7
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80 lines
2.4 KiB
C
80 lines
2.4 KiB
C
/* Copyright (C) 2002-2019 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <unistd.h>
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#include <list.h>
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#include <fork.h>
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#include <dl-sysdep.h>
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#include <tls.h>
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#include <string.h>
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#include <pthreadP.h>
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#include <libc-lock.h>
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#include <sysdep.h>
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#include <ldsodefs.h>
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unsigned long int *__fork_generation_pointer;
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#ifdef TLS_MULTIPLE_THREADS_IN_TCB
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void
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#else
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extern int __libc_multiple_threads attribute_hidden;
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int *
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#endif
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__libc_pthread_init (unsigned long int *ptr, void (*reclaim) (void),
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const struct pthread_functions *functions)
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{
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/* Remember the pointer to the generation counter in libpthread. */
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__fork_generation_pointer = ptr;
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/* Called by a child after fork. */
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__register_atfork (NULL, NULL, reclaim, NULL);
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#ifdef SHARED
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/* Copy the function pointers into an array in libc. This enables
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access with just one memory reference but moreso, it prevents
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hijacking the function pointers with just one pointer change. We
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"encrypt" the function pointers since we cannot write-protect the
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array easily enough. */
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union ptrhack
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{
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struct pthread_functions pf;
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# define NPTRS (sizeof (struct pthread_functions) / sizeof (void *))
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void *parr[NPTRS];
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} __attribute__ ((may_alias)) const *src;
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union ptrhack *dest;
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src = (const void *) functions;
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dest = (void *) &__libc_pthread_functions;
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for (size_t cnt = 0; cnt < NPTRS; ++cnt)
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{
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void *p = src->parr[cnt];
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PTR_MANGLE (p);
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dest->parr[cnt] = p;
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}
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__libc_pthread_functions_init = 1;
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#endif
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#ifndef TLS_MULTIPLE_THREADS_IN_TCB
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return &__libc_multiple_threads;
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#endif
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}
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