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/* ABI compatibility for 'longjmp' and 'siglongjmp' symbols in libpthread ABI.
X86 version.
Copyright (C) 1918-2020 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
<https://www.gnu.org/licenses/>. */
#include <pthreadP.h>
#include <jmp_buf-ssp.h>
#ifdef __x86_64__
# define SHADOW_STACK_POINTER_SIZE 8
#else
# define SHADOW_STACK_POINTER_SIZE 4
#endif
/* Assert that the priv field in struct pthread_unwind_buf has space
to store shadow stack pointer. */
_Static_assert ((offsetof (struct pthread_unwind_buf, priv)
<= SHADOW_STACK_POINTER_OFFSET)
&& ((offsetof (struct pthread_unwind_buf, priv)
+ sizeof (((struct pthread_unwind_buf *) 0)->priv))
>= (SHADOW_STACK_POINTER_OFFSET
+ SHADOW_STACK_POINTER_SIZE)),
"Shadow stack pointer is not within private storage "
"of pthread_unwind_buf.");
#include <shlib-compat.h>
/* libpthread once had its own longjmp (and siglongjmp alias), though there
was no apparent reason for it. There is no use in having a separate
symbol 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
longjmp and siglongjmp symbols in libpthread.so.
With an IFUNC resolver, it would be possible to avoid the indirection,
but the IFUNC resolver might run before the __libc_longjmp symbol has
been relocated, in which case the IFUNC resolver would not be able to
provide the correct address. */
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
static void __attribute__ ((noreturn, used))
longjmp_compat (jmp_buf env, int val)
{
/* NB: We call __libc_siglongjmp, instead of __libc_longjmp, since
__libc_longjmp is a private interface for cancellation which
doesn't restore shadow stack register. */
__libc_siglongjmp (env, val);
}
strong_alias (longjmp_compat, longjmp_alias)
compat_symbol (libpthread, longjmp_alias, longjmp, GLIBC_2_0);
strong_alias (longjmp_alias, siglongjmp_alias)
compat_symbol (libpthread, siglongjmp_alias, siglongjmp, GLIBC_2_0);
#endif
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