1062c5bc4SJason Schmidlapp /*
2062c5bc4SJason Schmidlapp * pthread_cancel.c
3062c5bc4SJason Schmidlapp *
4062c5bc4SJason Schmidlapp * Description:
5062c5bc4SJason Schmidlapp * POSIX thread functions related to thread cancellation.
6062c5bc4SJason Schmidlapp *
7062c5bc4SJason Schmidlapp * --------------------------------------------------------------------------
8062c5bc4SJason Schmidlapp *
9062c5bc4SJason Schmidlapp * Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems
10062c5bc4SJason Schmidlapp * Copyright(C) 2008 Jason Schmidlapp
11062c5bc4SJason Schmidlapp *
12062c5bc4SJason Schmidlapp * Contact Email: jschmidlapp@users.sourceforge.net
13062c5bc4SJason Schmidlapp *
14062c5bc4SJason Schmidlapp *
15062c5bc4SJason Schmidlapp * Based upon Pthreads-win32 - POSIX Threads Library for Win32
16062c5bc4SJason Schmidlapp * Copyright(C) 1998 John E. Bossom
17062c5bc4SJason Schmidlapp * Copyright(C) 1999,2005 Pthreads-win32 contributors
18062c5bc4SJason Schmidlapp *
19062c5bc4SJason Schmidlapp * Contact Email: rpj@callisto.canberra.edu.au
20062c5bc4SJason Schmidlapp *
21062c5bc4SJason Schmidlapp * The original list of contributors to the Pthreads-win32 project
22062c5bc4SJason Schmidlapp * is contained in the file CONTRIBUTORS.ptw32 included with the
23062c5bc4SJason Schmidlapp * source code distribution. The list can also be seen at the
24062c5bc4SJason Schmidlapp * following World Wide Web location:
25062c5bc4SJason Schmidlapp * http://sources.redhat.com/pthreads-win32/contributors.html
26062c5bc4SJason Schmidlapp *
27062c5bc4SJason Schmidlapp * This library is free software; you can redistribute it and/or
28062c5bc4SJason Schmidlapp * modify it under the terms of the GNU Lesser General Public
29062c5bc4SJason Schmidlapp * License as published by the Free Software Foundation; either
30062c5bc4SJason Schmidlapp * version 2 of the License, or (at your option) any later version.
31062c5bc4SJason Schmidlapp *
32062c5bc4SJason Schmidlapp * This library is distributed in the hope that it will be useful,
33062c5bc4SJason Schmidlapp * but WITHOUT ANY WARRANTY; without even the implied warranty of
34062c5bc4SJason Schmidlapp * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
35062c5bc4SJason Schmidlapp * Lesser General Public License for more details.
36062c5bc4SJason Schmidlapp *
37062c5bc4SJason Schmidlapp * You should have received a copy of the GNU Lesser General Public
38062c5bc4SJason Schmidlapp * License along with this library in the file COPYING.LIB;
39062c5bc4SJason Schmidlapp * if not, write to the Free Software Foundation, Inc.,
40062c5bc4SJason Schmidlapp * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
41062c5bc4SJason Schmidlapp */
42062c5bc4SJason Schmidlapp
43062c5bc4SJason Schmidlapp #include "pthread.h"
44062c5bc4SJason Schmidlapp #include "implement.h"
45062c5bc4SJason Schmidlapp #include <stdio.h>
46062c5bc4SJason Schmidlapp
47062c5bc4SJason Schmidlapp int
pthread_cancel(pthread_t thread)48062c5bc4SJason Schmidlapp pthread_cancel (pthread_t thread)
49062c5bc4SJason Schmidlapp /*
50062c5bc4SJason Schmidlapp * ------------------------------------------------------
51062c5bc4SJason Schmidlapp * DOCPUBLIC
52062c5bc4SJason Schmidlapp * This function requests cancellation of 'thread'.
53062c5bc4SJason Schmidlapp *
54062c5bc4SJason Schmidlapp * PARAMETERS
55062c5bc4SJason Schmidlapp * thread
56062c5bc4SJason Schmidlapp * reference to an instance of pthread_t
57062c5bc4SJason Schmidlapp *
58062c5bc4SJason Schmidlapp *
59062c5bc4SJason Schmidlapp * DESCRIPTION
60062c5bc4SJason Schmidlapp * This function requests cancellation of 'thread'.
61062c5bc4SJason Schmidlapp * NOTE: cancellation is asynchronous; use pthread_join to
62062c5bc4SJason Schmidlapp * wait for termination of 'thread' if necessary.
63062c5bc4SJason Schmidlapp *
64062c5bc4SJason Schmidlapp * RESULTS
65062c5bc4SJason Schmidlapp * 0 successfully requested cancellation,
66062c5bc4SJason Schmidlapp * ESRCH no thread found corresponding to 'thread',
67062c5bc4SJason Schmidlapp * ENOMEM implicit self thread create failed.
68062c5bc4SJason Schmidlapp * ------------------------------------------------------
69062c5bc4SJason Schmidlapp */
70062c5bc4SJason Schmidlapp {
71062c5bc4SJason Schmidlapp int result;
72062c5bc4SJason Schmidlapp int cancel_self;
73062c5bc4SJason Schmidlapp pthread_t self;
74062c5bc4SJason Schmidlapp pte_thread_t * tp;
75062c5bc4SJason Schmidlapp
76062c5bc4SJason Schmidlapp result = pthread_kill (thread, 0);
77062c5bc4SJason Schmidlapp
78062c5bc4SJason Schmidlapp if (0 != result)
79062c5bc4SJason Schmidlapp {
80062c5bc4SJason Schmidlapp return result;
81062c5bc4SJason Schmidlapp }
82062c5bc4SJason Schmidlapp
83*a12978ccSJeremy Soller if ((self = pthread_self ()) == NULL)
84062c5bc4SJason Schmidlapp {
85062c5bc4SJason Schmidlapp return ENOMEM;
86062c5bc4SJason Schmidlapp };
87062c5bc4SJason Schmidlapp
88062c5bc4SJason Schmidlapp /*
89062c5bc4SJason Schmidlapp * FIXME!!
90062c5bc4SJason Schmidlapp *
91062c5bc4SJason Schmidlapp * Can a thread cancel itself?
92062c5bc4SJason Schmidlapp *
93062c5bc4SJason Schmidlapp * The standard doesn't
94062c5bc4SJason Schmidlapp * specify an error to be returned if the target
95062c5bc4SJason Schmidlapp * thread is itself.
96062c5bc4SJason Schmidlapp *
97062c5bc4SJason Schmidlapp * If it may, then we need to ensure that a thread can't
98062c5bc4SJason Schmidlapp * deadlock itself trying to cancel itself asyncronously
99062c5bc4SJason Schmidlapp * (pthread_cancel is required to be an async-cancel
100062c5bc4SJason Schmidlapp * safe function).
101062c5bc4SJason Schmidlapp */
102062c5bc4SJason Schmidlapp cancel_self = pthread_equal (thread, self);
103062c5bc4SJason Schmidlapp
104*a12978ccSJeremy Soller tp = (pte_thread_t *) thread;
105062c5bc4SJason Schmidlapp
106062c5bc4SJason Schmidlapp /*
107062c5bc4SJason Schmidlapp * Lock for async-cancel safety.
108062c5bc4SJason Schmidlapp */
109062c5bc4SJason Schmidlapp (void) pthread_mutex_lock (&tp->cancelLock);
110062c5bc4SJason Schmidlapp
111062c5bc4SJason Schmidlapp if (tp->cancelType == PTHREAD_CANCEL_ASYNCHRONOUS
112062c5bc4SJason Schmidlapp && tp->cancelState == PTHREAD_CANCEL_ENABLE
113062c5bc4SJason Schmidlapp && tp->state < PThreadStateCanceling)
114062c5bc4SJason Schmidlapp {
115062c5bc4SJason Schmidlapp if (cancel_self)
116062c5bc4SJason Schmidlapp {
117062c5bc4SJason Schmidlapp tp->state = PThreadStateCanceling;
118062c5bc4SJason Schmidlapp tp->cancelState = PTHREAD_CANCEL_DISABLE;
119062c5bc4SJason Schmidlapp
120062c5bc4SJason Schmidlapp (void) pthread_mutex_unlock (&tp->cancelLock);
121062c5bc4SJason Schmidlapp pte_throw (PTE_EPS_CANCEL);
122062c5bc4SJason Schmidlapp
123062c5bc4SJason Schmidlapp /* Never reached */
124062c5bc4SJason Schmidlapp }
125062c5bc4SJason Schmidlapp else
126062c5bc4SJason Schmidlapp {
127062c5bc4SJason Schmidlapp /*
128062c5bc4SJason Schmidlapp * We don't support asynchronous cancellation for thread other than ourselves.
129062c5bc4SJason Schmidlapp * as it requires significant platform and OS specific functionality (see below).
130062c5bc4SJason Schmidlapp *
131062c5bc4SJason Schmidlapp * We should never get here, as we don't allow the cancellability type to be
132062c5bc4SJason Schmidlapp * sent to async.
133062c5bc4SJason Schmidlapp *
134062c5bc4SJason Schmidlapp * If you really wanted to implement async cancellation, you would probably need to
135062c5bc4SJason Schmidlapp * do something like the Win32 implement did, which is:
136062c5bc4SJason Schmidlapp * 1. Suspend the target thread.
137062c5bc4SJason Schmidlapp * 2. Replace the PC for the target thread to a routine that throws an exception
138062c5bc4SJason Schmidlapp * or does a longjmp, depending on cleanup method.
139062c5bc4SJason Schmidlapp * 3. Resume the target thread.
140062c5bc4SJason Schmidlapp *
141062c5bc4SJason Schmidlapp * Note that most of the async cancellation code is still in here if anyone
142062c5bc4SJason Schmidlapp * wanted to add the OS/platform specific stuff.
143062c5bc4SJason Schmidlapp */
144062c5bc4SJason Schmidlapp (void) pthread_mutex_unlock (&tp->cancelLock);
145062c5bc4SJason Schmidlapp
146062c5bc4SJason Schmidlapp result = EPERM;
147062c5bc4SJason Schmidlapp
148062c5bc4SJason Schmidlapp }
149062c5bc4SJason Schmidlapp }
150062c5bc4SJason Schmidlapp else
151062c5bc4SJason Schmidlapp {
152062c5bc4SJason Schmidlapp /*
153062c5bc4SJason Schmidlapp * Set for deferred cancellation.
154062c5bc4SJason Schmidlapp */
155062c5bc4SJason Schmidlapp if (tp->state < PThreadStateCancelPending)
156062c5bc4SJason Schmidlapp {
157062c5bc4SJason Schmidlapp tp->state = PThreadStateCancelPending;
158062c5bc4SJason Schmidlapp
159062c5bc4SJason Schmidlapp if (pte_osThreadCancel(tp->threadId) != PTE_OS_OK)
160062c5bc4SJason Schmidlapp {
161062c5bc4SJason Schmidlapp result = ESRCH;
162062c5bc4SJason Schmidlapp }
163062c5bc4SJason Schmidlapp }
164062c5bc4SJason Schmidlapp else if (tp->state >= PThreadStateCanceling)
165062c5bc4SJason Schmidlapp {
166062c5bc4SJason Schmidlapp result = ESRCH;
167062c5bc4SJason Schmidlapp }
168062c5bc4SJason Schmidlapp
169062c5bc4SJason Schmidlapp (void) pthread_mutex_unlock (&tp->cancelLock);
170062c5bc4SJason Schmidlapp }
171062c5bc4SJason Schmidlapp
172062c5bc4SJason Schmidlapp return (result);
173062c5bc4SJason Schmidlapp }
174