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04277e02 | 1 | /* Copyright (C) 2002-2019 Free Software Foundation, Inc. |
76a50749 UD |
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 | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
76a50749 UD |
18 | |
19 | #include <setjmp.h> | |
20 | #include <stdlib.h> | |
21 | #include "pthreadP.h" | |
a2f0363f | 22 | #include <futex-internal.h> |
76a50749 UD |
23 | |
24 | ||
bdb04f92 UD |
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. */ | |
28 | int | |
29 | attribute_hidden | |
30 | __pthread_enable_asynccancel (void) | |
31 | { | |
32 | struct pthread *self = THREAD_SELF; | |
b22d701b | 33 | int oldval = THREAD_GETMEM (self, cancelhandling); |
bdb04f92 UD |
34 | |
35 | while (1) | |
36 | { | |
bdb04f92 UD |
37 | int newval = oldval | CANCELTYPE_BITMASK; |
38 | ||
39 | if (newval == oldval) | |
40 | break; | |
41 | ||
b22d701b UD |
42 | int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, |
43 | oldval); | |
a1ffb40e | 44 | if (__glibc_likely (curval == oldval)) |
bdb04f92 UD |
45 | { |
46 | if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval)) | |
47 | { | |
48 | THREAD_SETMEM (self, result, PTHREAD_CANCELED); | |
9ae0909b | 49 | __do_cancel (); |
bdb04f92 UD |
50 | } |
51 | ||
52 | break; | |
53 | } | |
b22d701b UD |
54 | |
55 | /* Prepare the next round. */ | |
56 | oldval = curval; | |
bdb04f92 UD |
57 | } |
58 | ||
59 | return oldval; | |
60 | } | |
61 | ||
62 | ||
63 | void | |
83b09837 | 64 | attribute_hidden |
bdb04f92 UD |
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; | |
1a7f254b | 73 | int newval; |
d5c157a9 | 74 | |
b22d701b | 75 | int oldval = THREAD_GETMEM (self, cancelhandling); |
bdb04f92 UD |
76 | |
77 | while (1) | |
78 | { | |
1a7f254b | 79 | newval = oldval & ~CANCELTYPE_BITMASK; |
bdb04f92 | 80 | |
b22d701b UD |
81 | int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, |
82 | oldval); | |
a1ffb40e | 83 | if (__glibc_likely (curval == oldval)) |
bdb04f92 | 84 | break; |
b22d701b UD |
85 | |
86 | /* Prepare the next round. */ | |
87 | oldval = curval; | |
bdb04f92 | 88 | } |
1a7f254b UD |
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. */ | |
9437b427 UD |
94 | while (__builtin_expect ((newval & (CANCELING_BITMASK | CANCELED_BITMASK)) |
95 | == CANCELING_BITMASK, 0)) | |
1a7f254b | 96 | { |
a2f0363f TR |
97 | futex_wait_simple ((unsigned int *) &self->cancelhandling, newval, |
98 | FUTEX_PRIVATE); | |
1a7f254b UD |
99 | newval = THREAD_GETMEM (self, cancelhandling); |
100 | } | |
bdb04f92 | 101 | } |