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1 /* _longjmp_unwind -- Clean up stack frames unwound by longjmp. Hurd version.
2 Copyright (C) 1995-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
19 #include <jmpbuf-unwind.h>
20 #include <hurd/userlink.h>
21 #include <hurd/signal.h>
22 #include <hurd/sigpreempt.h>
25 #include <pointer_guard.h>
27 #ifndef _JMPBUF_UNWINDS
28 #error "<jmpbuf-unwind.h> fails to define _JMPBUF_UNWINDS"
31 static inline uintptr_t
32 demangle_ptr (uintptr_t x
)
38 /* This function is called by `longjmp' (with its arguments) to restore
39 active resources to a sane state before the frames code using them are
43 _longjmp_unwind (jmp_buf env
, int val
)
45 struct hurd_sigstate
*ss
= _hurd_self_sigstate ();
46 struct hurd_userlink
*link
;
48 /* All access to SS->active_resources must take place inside a critical
49 section where signal handlers cannot run. */
50 __spin_lock (&ss
->lock
);
51 assert (! __spin_lock_locked (&ss
->critical_section_lock
));
52 __spin_lock (&ss
->critical_section_lock
);
54 /* Remove local signal preemptors being unwound past. */
56 && _JMPBUF_UNWINDS (env
[0].__jmpbuf
, ss
->preemptors
, demangle_ptr
))
57 ss
->preemptors
= ss
->preemptors
->next
;
59 __spin_unlock (&ss
->lock
);
61 /* Iterate over the current thread's list of active resources.
62 Process the head portion of the list whose links reside
63 in stack frames being unwound by this jump. */
65 for (link
= ss
->active_resources
;
66 link
&& _JMPBUF_UNWINDS (env
[0].__jmpbuf
, link
, demangle_ptr
);
67 link
= link
->thread
.next
)
68 /* Remove this link from the resource's users list,
69 since the frame using the resource is being unwound.
70 This call returns nonzero if that was the last user. */
71 if (_hurd_userlink_unlink (link
))
72 /* One of the frames being unwound by the longjmp was the last user
73 of its resource. Call the cleanup function to deallocate it. */
74 (*link
->cleanup
) (link
->cleanup_data
, env
, val
);
76 _hurd_critical_section_unlock (ss
);