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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 | 18 | |
8c2e9a29 | 19 | #include <errno.h> |
76a50749 | 20 | #include <signal.h> |
2f531bbb | 21 | #include <stdlib.h> |
76a50749 | 22 | #include "pthreadP.h" |
2f531bbb | 23 | #include <atomic.h> |
e814f748 | 24 | #include <sysdep.h> |
c579f48e | 25 | #include <unistd.h> |
76a50749 UD |
26 | |
27 | int | |
fa872e1b | 28 | __pthread_cancel (pthread_t th) |
76a50749 UD |
29 | { |
30 | volatile struct pthread *pd = (volatile struct pthread *) th; | |
31 | ||
8c2e9a29 UD |
32 | /* Make sure the descriptor is valid. */ |
33 | if (INVALID_TD_P (pd)) | |
34 | /* Not a valid thread handle. */ | |
35 | return ESRCH; | |
36 | ||
9d79e037 UD |
37 | #ifdef SHARED |
38 | pthread_cancel_init (); | |
39 | #endif | |
8c2e9a29 | 40 | int result = 0; |
5a3ab2fc UD |
41 | int oldval; |
42 | int newval; | |
43 | do | |
76a50749 | 44 | { |
9437b427 | 45 | again: |
5a3ab2fc UD |
46 | oldval = pd->cancelhandling; |
47 | newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK; | |
76a50749 UD |
48 | |
49 | /* Avoid doing unnecessary work. The atomic operation can | |
50 | potentially be expensive if the bug has to be locked and | |
51 | remote cache lines have to be invalidated. */ | |
52 | if (oldval == newval) | |
53 | break; | |
54 | ||
55 | /* If the cancellation is handled asynchronously just send a | |
56 | signal. We avoid this if possible since it's more | |
57 | expensive. */ | |
58 | if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval)) | |
59 | { | |
e320ef46 | 60 | /* Mark the cancellation as "in progress". */ |
9437b427 UD |
61 | if (atomic_compare_and_exchange_bool_acq (&pd->cancelhandling, |
62 | oldval | CANCELING_BITMASK, | |
63 | oldval)) | |
64 | goto again; | |
e320ef46 | 65 | |
76a50749 UD |
66 | /* The cancellation handler will take care of marking the |
67 | thread as canceled. */ | |
fa872e1b | 68 | pid_t pid = __getpid (); |
e814f748 | 69 | |
c579f48e AZ |
70 | INTERNAL_SYSCALL_DECL (err); |
71 | int val = INTERNAL_SYSCALL_CALL (tgkill, err, pid, pd->tid, | |
72 | SIGCANCEL); | |
e814f748 UD |
73 | if (INTERNAL_SYSCALL_ERROR_P (val, err)) |
74 | result = INTERNAL_SYSCALL_ERRNO (val, err); | |
76a50749 UD |
75 | |
76 | break; | |
77 | } | |
439bf404 | 78 | |
2f531bbb RM |
79 | /* A single-threaded process should be able to kill itself, since |
80 | there is nothing in the POSIX specification that says that it | |
81 | cannot. So we set multiple_threads to true so that cancellation | |
82 | points get executed. */ | |
439bf404 SP |
83 | THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1); |
84 | #ifndef TLS_MULTIPLE_THREADS_IN_TCB | |
85 | __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1; | |
86 | #endif | |
76a50749 | 87 | } |
5a3ab2fc UD |
88 | /* Mark the thread as canceled. This has to be done |
89 | atomically since other bits could be modified as well. */ | |
90 | while (atomic_compare_and_exchange_bool_acq (&pd->cancelhandling, newval, | |
91 | oldval)); | |
76a50749 | 92 | |
e9cb48ab | 93 | return result; |
76a50749 | 94 | } |
fa872e1b | 95 | weak_alias (__pthread_cancel, pthread_cancel) |
ef2bb413 | 96 | |
fa872e1b | 97 | PTHREAD_STATIC_FN_REQUIRE (__pthread_create) |