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[glibc.git] / sysdeps / mach / hurd / jmp-unwind.c
blobe0e16e28b2eb82dcd1a77907fc167d5cebe2cf42
1 /* _longjmp_unwind -- Clean up stack frames unwound by longjmp. Hurd version.
2 Copyright (C) 1995,1996,2005,2006 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, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <jmpbuf-unwind.h>
21 #include <hurd/userlink.h>
22 #include <hurd/signal.h>
23 #include <hurd/sigpreempt.h>
24 #include <assert.h>
25 #include <stdint.h>
28 #ifndef _JMPBUF_UNWINDS
29 #error "<jmpbuf-unwind.h> fails to define _JMPBUF_UNWINDS"
30 #endif
32 static inline uintptr_t
33 demangle_ptr (uintptr_t x)
35 # ifdef PTR_DEMANGLE
36 PTR_DEMANGLE (x);
37 # endif
38 return x;
41 /* This function is called by `longjmp' (with its arguments) to restore
42 active resources to a sane state before the frames code using them are
43 jumped out of. */
45 void
46 _longjmp_unwind (jmp_buf env, int val)
48 struct hurd_sigstate *ss = _hurd_self_sigstate ();
49 struct hurd_userlink *link;
51 /* All access to SS->active_resources must take place inside a critical
52 section where signal handlers cannot run. */
53 __spin_lock (&ss->lock);
54 assert (! __spin_lock_locked (&ss->critical_section_lock));
55 __spin_lock (&ss->critical_section_lock);
57 /* Remove local signal preemptors being unwound past. */
58 while (ss->preemptors &&
59 _JMPBUF_UNWINDS (env[0].__jmpbuf, ss->preemptors, demangle_ptr))
60 ss->preemptors = ss->preemptors->next;
62 __spin_unlock (&ss->lock);
64 /* Iterate over the current thread's list of active resources.
65 Process the head portion of the list whose links reside
66 in stack frames being unwound by this jump. */
68 for (link = ss->active_resources;
69 link && _JMPBUF_UNWINDS (env[0].__jmpbuf, link, demangle_ptr);
70 link = link->thread.next)
71 /* Remove this link from the resource's users list,
72 since the frame using the resource is being unwound.
73 This call returns nonzero if that was the last user. */
74 if (_hurd_userlink_unlink (link))
75 /* One of the frames being unwound by the longjmp was the last user
76 of its resource. Call the cleanup function to deallocate it. */
77 (*link->cleanup) (link->cleanup_data, env, val);
79 _hurd_critical_section_unlock (ss);