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/* Copyright (C) 2011-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
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 <jmpbuf-offsets.h>
#include <sysdep.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stackinfo.h>
#ifdef _STACK_GROWS_DOWN
#define called_from(this, saved) ((this) < (saved))
#else
#define called_from(this, saved) ((this) > (saved))
#endif
extern void ____longjmp_chk (__jmp_buf __env, int __val)
__attribute__ ((__noreturn__));
void ____longjmp_chk (__jmp_buf env, int val)
{
void *this_frame = __builtin_frame_address (0);
void *saved_frame = JB_FRAME_ADDRESS (env);
INTERNAL_SYSCALL_DECL (err);
stack_t ss;
/* If "env" is from a frame that called us, we're all set. */
if (called_from(this_frame, saved_frame))
__longjmp (env, val);
/* If we can't get the current stack state, give up and do the longjmp. */
if (INTERNAL_SYSCALL (sigaltstack, err, 2, NULL, &ss) != 0)
__longjmp (env, val);
/* If we we are executing on the alternate stack and within the
bounds, do the longjmp. */
if (ss.ss_flags == SS_ONSTACK
&& (this_frame >= ss.ss_sp && this_frame < (ss.ss_sp + ss.ss_size)))
__longjmp (env, val);
__fortify_fail ("longjmp causes uninitialized stack frame");
}
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