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1/* Copyright (C) 2002-2019 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
4
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.
9
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.
14
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 <http://www.gnu.org/licenses/>. */
18
19#include <setjmp.h>
20#include <stdlib.h>
21#include "pthreadP.h"
22#include <futex-internal.h>
23
24
25/* The next two functions are similar to pthread_setcanceltype() but
26 more specialized for the use in the cancelable functions like write().
27 They do not need to check parameters etc. */
28int
29attribute_hidden
30__pthread_enable_asynccancel (void)
31{
32 struct pthread *self = THREAD_SELF;
33 int oldval = THREAD_GETMEM (self, cancelhandling);
34
35 while (1)
36 {
37 int newval = oldval | CANCELTYPE_BITMASK;
38
39 if (newval == oldval)
40 break;
41
42 int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
43 oldval);
44 if (__glibc_likely (curval == oldval))
45 {
46 if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
47 {
48 THREAD_SETMEM (self, result, PTHREAD_CANCELED);
49 __do_cancel ();
50 }
51
52 break;
53 }
54
55 /* Prepare the next round. */
56 oldval = curval;
57 }
58
59 return oldval;
60}
61
62
63void
64attribute_hidden
65__pthread_disable_asynccancel (int oldtype)
66{
67 /* If asynchronous cancellation was enabled before we do not have
68 anything to do. */
69 if (oldtype & CANCELTYPE_BITMASK)
70 return;
71
72 struct pthread *self = THREAD_SELF;
73 int newval;
74
75 int oldval = THREAD_GETMEM (self, cancelhandling);
76
77 while (1)
78 {
79 newval = oldval & ~CANCELTYPE_BITMASK;
80
81 int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
82 oldval);
83 if (__glibc_likely (curval == oldval))
84 break;
85
86 /* Prepare the next round. */
87 oldval = curval;
88 }
89
90 /* We cannot return when we are being canceled. Upon return the
91 thread might be things which would have to be undone. The
92 following loop should loop until the cancellation signal is
93 delivered. */
94 while (__builtin_expect ((newval & (CANCELING_BITMASK | CANCELED_BITMASK))
95 == CANCELING_BITMASK, 0))
96 {
97 futex_wait_simple ((unsigned int *) &self->cancelhandling, newval,
98 FUTEX_PRIVATE);
99 newval = THREAD_GETMEM (self, cancelhandling);
100 }
101}
102

Warning: That file was not part of the compilation database. It may have many parsing errors.