1 /* Copyright (C) 2002-2016 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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, see
17 <http://www.gnu.org/licenses/>. */
28 pthread_cancel (pthread_t th
)
30 volatile struct pthread
*pd
= (volatile struct pthread
*) th
;
32 /* Make sure the descriptor is valid. */
33 if (INVALID_TD_P (pd
))
34 /* Not a valid thread handle. */
38 pthread_cancel_init ();
46 oldval
= pd
->cancelhandling
;
47 newval
= oldval
| CANCELING_BITMASK
| CANCELED_BITMASK
;
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. */
55 /* If the cancellation is handled asynchronously just send a
56 signal. We avoid this if possible since it's more
58 if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval
))
60 /* Mark the cancellation as "in progress". */
61 if (atomic_compare_and_exchange_bool_acq (&pd
->cancelhandling
,
62 oldval
| CANCELING_BITMASK
,
67 /* The cancellation handler will take care of marking the
68 thread as canceled. */
69 pid_t pid
= getpid ();
71 INTERNAL_SYSCALL_DECL (err
);
72 int val
= INTERNAL_SYSCALL_CALL (tgkill
, err
, pid
, pd
->tid
,
74 if (INTERNAL_SYSCALL_ERROR_P (val
, err
))
75 result
= INTERNAL_SYSCALL_ERRNO (val
, err
);
77 /* It should be impossible to get here at all, since
78 pthread_setcanceltype should never have allowed
79 PTHREAD_CANCEL_ASYNCHRONOUS to be set. */
86 /* A single-threaded process should be able to kill itself, since
87 there is nothing in the POSIX specification that says that it
88 cannot. So we set multiple_threads to true so that cancellation
89 points get executed. */
90 THREAD_SETMEM (THREAD_SELF
, header
.multiple_threads
, 1);
91 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
92 __pthread_multiple_threads
= *__libc_multiple_threads_ptr
= 1;
95 /* Mark the thread as canceled. This has to be done
96 atomically since other bits could be modified as well. */
97 while (atomic_compare_and_exchange_bool_acq (&pd
->cancelhandling
, newval
,
103 PTHREAD_STATIC_FN_REQUIRE (pthread_create
)