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d6163dfd38
If libpthread is included in libc, it is not necessary to delay initialization of the lock/unlock function pointers until libpthread is loaded. This eliminates two unprotected function pointers from _rtld_global and removes some initialization code from libpthread. Tested-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
54 lines
2.2 KiB
C
54 lines
2.2 KiB
C
/* Recursive locking implementation for the dynamic loader. NPTL version.
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Copyright (C) 2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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<https://www.gnu.org/licenses/>. */
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/* Use the mutex implementation in libc (assuming PTHREAD_IN_LIBC). */
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#include <assert.h>
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#include <first-versions.h>
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#include <ldsodefs.h>
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__typeof (pthread_mutex_lock) *___rtld_mutex_lock attribute_relro;
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__typeof (pthread_mutex_unlock) *___rtld_mutex_unlock attribute_relro;
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void
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__rtld_mutex_init (void)
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{
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/* There is an implicit assumption here that the lock counters are
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zero and this function is called while nothing is locked. For
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early initialization of the mutex functions this is true because
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it happens directly in dl_main in elf/rtld.c, and not some ELF
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constructor while holding loader locks. */
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struct link_map *libc_map = GL (dl_ns)[LM_ID_BASE].libc_map;
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const ElfW(Sym) *sym
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= _dl_lookup_direct (libc_map, "pthread_mutex_lock",
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0x4f152227, /* dl_new_hash output. */
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FIRST_VERSION_libc_pthread_mutex_lock_STRING,
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FIRST_VERSION_libc_pthread_mutex_lock_HASH);
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assert (sym != NULL);
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___rtld_mutex_lock = DL_SYMBOL_ADDRESS (libc_map, sym);
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sym = _dl_lookup_direct (libc_map, "pthread_mutex_unlock",
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0x7dd7aaaa, /* dl_new_hash output. */
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FIRST_VERSION_libc_pthread_mutex_unlock_STRING,
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FIRST_VERSION_libc_pthread_mutex_unlock_HASH);
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assert (sym != NULL);
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___rtld_mutex_unlock = DL_SYMBOL_ADDRESS (libc_map, sym);
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}
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