glibc/nptl/pt-vfork.c

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/* vfork ABI-compatibility entry points for libpthread.
Copyright (C) 2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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 <unistd.h>
#include <shlib-compat.h>
/* libpthread used to have its own vfork implementation that differed
from libc's only in having a pointless micro-optimization. There
is no longer any use to having a separate copy in libpthread, but
the historical ABI requires it. For static linking, there is no
need to provide anything here--the libc version will be linked in.
For shared library ABI compatibility, there must be __vfork and
vfork symbols in libpthread.so; so we define them using IFUNC to
redirect to the libc function. */
#if (SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_20) \
|| SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20))
extern __typeof (vfork) __libc_vfork; /* Defined in libc. */
# ifdef HAVE_IFUNC
attribute_hidden __attribute__ ((used))
__typeof (vfork) *
vfork_ifunc (void)
{
return &__libc_vfork;
}
# ifdef HAVE_ASM_SET_DIRECTIVE
# define DEFINE_VFORK(name) \
asm (".set " #name ", vfork_ifunc\n" \
".globl " #name "\n" \
".type " #name ", %gnu_indirect_function");
# else
# define DEFINE_VFORK(name) \
asm (#name " = vfork_ifunc\n" \
".globl " #name "\n" \
".type " #name ", %gnu_indirect_function");
# endif
# else
attribute_hidden
pid_t
vfork_compat (void)
{
return __libc_vfork ();
}
# define DEFINE_VFORK(name) weak_alias (vfork_compat, name)
# endif
#endif
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_20)
DEFINE_VFORK (vfork)
#endif
#if SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20)
DEFINE_VFORK (__vfork)
#endif