1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/**************************************************************************
* sched/pthread/pthread_cancel.c
*
* Copyright (C) 2007, 2009, 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
**************************************************************************/
/**************************************************************************
* Included Files
**************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
#include "sched/sched.h"
#include "pthread/pthread.h"
/**************************************************************************
* Private Definitions
**************************************************************************/
/**************************************************************************
* Private Types
**************************************************************************/
/**************************************************************************
* Private Function Prototypes
**************************************************************************/
/**************************************************************************
* Global Variables
**************************************************************************/
/**************************************************************************
* Private Variables
**************************************************************************/
/**************************************************************************
* Private Functions
**************************************************************************/
/**************************************************************************
* Public Functions
**************************************************************************/
int pthread_cancel(pthread_t thread)
{
struct tcb_s *tcb;
/* First, make sure that the handle references a valid thread */
if (!thread)
{
/* pid == 0 is the IDLE task. Callers cannot cancel the
* IDLE task.
*/
return ESRCH;
}
tcb = sched_gettcb((pid_t)thread);
if (!tcb)
{
/* The pid does not correspond to any known thread. The thread
* has probably already exited.
*/
return ESRCH;
}
/* Check to see if this thread has the non-cancelable bit set in its
* flags. Suppress context changes for a bit so that the flags are stable.
* (the flags should not change in interrupt handling.
*/
sched_lock();
if ((tcb->flags & TCB_FLAG_NONCANCELABLE) != 0)
{
/* Then we cannot cancel the thread now. Here is how this is
* supposed to work:
*
* "When cancelability is disabled, all cancels are held pending
* in the target thread until the thread changes the cancelability.
* When cancelability is deferred, all cancels are held pending in
* the target thread until the thread changes the cancelability, calls
* a function which is a cancellation point or calls pthread_testcancel(),
* thus creating a cancellation point. When cancelability is asynchronous,
* all cancels are acted upon immediately, interrupting the thread with its
* processing."
*/
tcb->flags |= TCB_FLAG_CANCEL_PENDING;
sched_unlock();
return OK;
}
sched_unlock();
/* Check to see if the ID refers to ourselves.. this would be the
* same as pthread_exit(PTHREAD_CANCELED).
*/
if (tcb == (struct tcb_s*)g_readytorun.head)
{
pthread_exit(PTHREAD_CANCELED);
}
/* Complete pending join operations */
(void)pthread_completejoin((pid_t)thread, PTHREAD_CANCELED);
/* Then let pthread_delete do the real work */
task_delete((pid_t)thread);
return OK;
}
|
