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41d6f74e6c
With commit f0b2132b35 ("ld.so:
Support moving versioned symbols between sonames [BZ #24741]"), the
dynamic linker will find the definition of vfork in libc and binds
a vfork reference to that symbol, even if the soname in the version
reference says that the symbol should be located in libpthread.
As a result, the forwarder (whether it's IFUNC-based or a duplicate
of the libc implementation) is no longer necessary.
On older architectures, a placeholder symbol is required, to make sure
that the GLIBC_2.1.2 symbol version does not go away, or is turned in
to a weak symbol definition by the link editor. (The symbol version
needs to preserved so that the symbol coverage check in
elf/dl-version.c does not fail for old binaries.)
mips32 is an outlier: It defined __vfork@@GLIBC_2.2, but the
baseline is GLIBC_2.0. Since there are other @@GLIBC_2.2 symbols,
the placeholder symbol is not needed there.
38 lines
1.6 KiB
C
38 lines
1.6 KiB
C
/* Placeholder definitions to pull in removed symbol versions.
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Copyright (C) 2019 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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<http://www.gnu.org/licenses/>. */
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#include <shlib-compat.h>
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/* This is an unused compatibility symbol definition, to prevent ld
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from creating a weak version definition for GLIBC_2.1.2. (__vfork
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used to be defined at that version, but it is now provided by libc,
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and there are no versions left in libpthread for that symbol
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version.) If the ABI baseline for glibc is the GLIBC_2.2 symbol
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version or later, the placeholder symbol is not needed because
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there are plenty of other symbols which populate those later
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versions. */
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#if (SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_2))
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void
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attribute_compat_text_section
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__libpthread_version_placeholder (void)
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{
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}
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compat_symbol (libpthread, __libpthread_version_placeholder,
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__libpthread_version_placeholder, GLIBC_2_1_2);
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#endif
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