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d614a753 | 1 | /* Copyright (C) 2002-2020 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(). | |
676b2f20 CD |
27 | They do not need to check parameters etc. These functions must be |
28 | AS-safe, with the exception of the actual cancellation, because they | |
29 | are called by wrappers around AS-safe functions like write().*/ | |
bdb04f92 UD |
30 | int |
31 | attribute_hidden | |
32 | __pthread_enable_asynccancel (void) | |
33 | { | |
34 | struct pthread *self = THREAD_SELF; | |
b22d701b | 35 | int oldval = THREAD_GETMEM (self, cancelhandling); |
bdb04f92 UD |
36 | |
37 | while (1) | |
38 | { | |
bdb04f92 UD |
39 | int newval = oldval | CANCELTYPE_BITMASK; |
40 | ||
41 | if (newval == oldval) | |
42 | break; | |
43 | ||
b22d701b UD |
44 | int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, |
45 | oldval); | |
a1ffb40e | 46 | if (__glibc_likely (curval == oldval)) |
bdb04f92 UD |
47 | { |
48 | if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval)) | |
49 | { | |
50 | THREAD_SETMEM (self, result, PTHREAD_CANCELED); | |
9ae0909b | 51 | __do_cancel (); |
bdb04f92 UD |
52 | } |
53 | ||
54 | break; | |
55 | } | |
b22d701b UD |
56 | |
57 | /* Prepare the next round. */ | |
58 | oldval = curval; | |
bdb04f92 UD |
59 | } |
60 | ||
61 | return oldval; | |
62 | } | |
63 | ||
676b2f20 CD |
64 | /* See the comment for __pthread_enable_asynccancel regarding |
65 | the AS-safety of this function. */ | |
bdb04f92 | 66 | void |
83b09837 | 67 | attribute_hidden |
bdb04f92 UD |
68 | __pthread_disable_asynccancel (int oldtype) |
69 | { | |
70 | /* If asynchronous cancellation was enabled before we do not have | |
71 | anything to do. */ | |
72 | if (oldtype & CANCELTYPE_BITMASK) | |
73 | return; | |
74 | ||
75 | struct pthread *self = THREAD_SELF; | |
1a7f254b | 76 | int newval; |
d5c157a9 | 77 | |
b22d701b | 78 | int oldval = THREAD_GETMEM (self, cancelhandling); |
bdb04f92 UD |
79 | |
80 | while (1) | |
81 | { | |
1a7f254b | 82 | newval = oldval & ~CANCELTYPE_BITMASK; |
bdb04f92 | 83 | |
b22d701b UD |
84 | int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, |
85 | oldval); | |
a1ffb40e | 86 | if (__glibc_likely (curval == oldval)) |
bdb04f92 | 87 | break; |
b22d701b UD |
88 | |
89 | /* Prepare the next round. */ | |
90 | oldval = curval; | |
bdb04f92 | 91 | } |
1a7f254b UD |
92 | |
93 | /* We cannot return when we are being canceled. Upon return the | |
94 | thread might be things which would have to be undone. The | |
95 | following loop should loop until the cancellation signal is | |
96 | delivered. */ | |
9437b427 UD |
97 | while (__builtin_expect ((newval & (CANCELING_BITMASK | CANCELED_BITMASK)) |
98 | == CANCELING_BITMASK, 0)) | |
1a7f254b | 99 | { |
a2f0363f TR |
100 | futex_wait_simple ((unsigned int *) &self->cancelhandling, newval, |
101 | FUTEX_PRIVATE); | |
1a7f254b UD |
102 | newval = THREAD_GETMEM (self, cancelhandling); |
103 | } | |
bdb04f92 | 104 | } |