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/* _longjmp_unwind -- Clean up stack frames unwound by longjmp. Hurd version.
Copyright (C) 1995-2022 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 <jmpbuf-unwind.h>
#include <hurd/userlink.h>
#include <hurd/signal.h>
#include <hurd/sigpreempt.h>
#include <assert.h>
#include <stdint.h>
#include <pointer_guard.h>
#ifndef _JMPBUF_UNWINDS
#error "<jmpbuf-unwind.h> fails to define _JMPBUF_UNWINDS"
#endif
static inline uintptr_t
demangle_ptr (uintptr_t x)
{
PTR_DEMANGLE (x);
return x;
}
/* This function is called by `longjmp' (with its arguments) to restore
active resources to a sane state before the frames code using them are
jumped out of. */
void
_longjmp_unwind (jmp_buf env, int val)
{
struct hurd_sigstate *ss = _hurd_self_sigstate ();
struct hurd_userlink *link;
/* All access to SS->active_resources must take place inside a critical
section where signal handlers cannot run. */
__spin_lock (&ss->lock);
assert (! __spin_lock_locked (&ss->critical_section_lock));
__spin_lock (&ss->critical_section_lock);
/* Remove local signal preemptors being unwound past. */
while (ss->preemptors
&& _JMPBUF_UNWINDS (env[0].__jmpbuf, ss->preemptors, demangle_ptr))
ss->preemptors = ss->preemptors->next;
__spin_unlock (&ss->lock);
/* Iterate over the current thread's list of active resources.
Process the head portion of the list whose links reside
in stack frames being unwound by this jump. */
for (link = ss->active_resources;
link && _JMPBUF_UNWINDS (env[0].__jmpbuf, link, demangle_ptr);
link = link->thread.next)
/* Remove this link from the resource's users list,
since the frame using the resource is being unwound.
This call returns nonzero if that was the last user. */
if (_hurd_userlink_unlink (link))
/* One of the frames being unwound by the longjmp was the last user
of its resource. Call the cleanup function to deallocate it. */
(*link->cleanup) (link->cleanup_data, env, val);
_hurd_critical_section_unlock (ss);
}
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