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
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/* Linuxthreads - a simple clone()-based implementation of Posix */
/* threads for Linux. */
/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
/* */
/* This program is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU Library General Public License */
/* as published by the Free Software Foundation; either version 2 */
/* of the License, or (at your option) any later version. */
/* */
/* This program is distributed in the hope that it will be useful, */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
/* GNU Library General Public License for more details. */
/* Thread termination and joining */
#include <errno.h>
#include <sched.h>
#include <stdlib.h>
#include <unistd.h>
#include "pthread.h"
#include "internals.h"
#include "spinlock.h"
#include "restart.h"
void pthread_exit(void * retval)
{
__pthread_do_exit (retval, CURRENT_STACK_FRAME);
}
void __pthread_do_exit(void *retval, char *currentframe)
{
pthread_descr self = thread_self();
pthread_descr joining;
struct pthread_request request;
/* Reset the cancellation flag to avoid looping if the cleanup handlers
contain cancellation points */
THREAD_SETMEM(self, p_canceled, 0);
/* Call cleanup functions and destroy the thread-specific data */
__pthread_perform_cleanup(currentframe);
__pthread_destroy_specifics();
/* Store return value */
__pthread_lock(THREAD_GETMEM(self, p_lock), self);
THREAD_SETMEM(self, p_retval, retval);
/* See whether we have to signal the death. */
if (THREAD_GETMEM(self, p_report_events))
{
/* See whether TD_DEATH is in any of the mask. */
int idx = __td_eventword (TD_DEATH);
uint32_t mask = __td_eventmask (TD_DEATH);
if ((mask & (__pthread_threads_events.event_bits[idx]
| THREAD_GETMEM_NC(self,
p_eventbuf.eventmask.event_bits[idx])))
!= 0)
{
/* Yep, we have to signal the death. */
THREAD_SETMEM(self, p_eventbuf.eventnum, TD_DEATH);
THREAD_SETMEM(self, p_eventbuf.eventdata, self);
__pthread_last_event = self;
/* Now call the function to signal the event. */
__linuxthreads_death_event();
}
}
/* Say that we've terminated */
THREAD_SETMEM(self, p_terminated, 1);
/* See if someone is joining on us */
joining = THREAD_GETMEM(self, p_joining);
__pthread_unlock(THREAD_GETMEM(self, p_lock));
/* Restart joining thread if any */
if (joining != NULL) restart(joining);
/* If this is the initial thread, block until all threads have terminated.
If another thread calls exit, we'll be terminated from our signal
handler. */
if (self == __pthread_main_thread && __pthread_manager_request >= 0) {
request.req_thread = self;
request.req_kind = REQ_MAIN_THREAD_EXIT;
TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
(char *)&request, sizeof(request)));
suspend(self);
/* Main thread flushes stdio streams and runs atexit functions.
It also calls a handler within LinuxThreads which sends a process exit
request to the thread manager. */
exit(0);
}
/* Threads other than the main one terminate without flushing stdio streams
or running atexit functions. */
_exit(0);
}
/* Function called by pthread_cancel to remove the thread from
waiting on a condition variable queue. */
static int join_extricate_func(void *obj, pthread_descr th)
{
volatile pthread_descr self = thread_self();
pthread_handle handle = obj;
pthread_descr jo;
int did_remove = 0;
__pthread_lock(&handle->h_lock, self);
jo = handle->h_descr;
did_remove = jo->p_joining != NULL;
jo->p_joining = NULL;
__pthread_unlock(&handle->h_lock);
return did_remove;
}
int pthread_join(pthread_t thread_id, void ** thread_return)
{
volatile pthread_descr self = thread_self();
struct pthread_request request;
pthread_handle handle = thread_handle(thread_id);
pthread_descr th;
pthread_extricate_if extr;
int already_canceled = 0;
/* Set up extrication interface */
extr.pu_object = handle;
extr.pu_extricate_func = join_extricate_func;
__pthread_lock(&handle->h_lock, self);
if (nonexisting_handle(handle, thread_id)) {
__pthread_unlock(&handle->h_lock);
return ESRCH;
}
th = handle->h_descr;
if (th == self) {
__pthread_unlock(&handle->h_lock);
return EDEADLK;
}
/* If detached or already joined, error */
if (th->p_detached || th->p_joining != NULL) {
__pthread_unlock(&handle->h_lock);
return EINVAL;
}
/* If not terminated yet, suspend ourselves. */
if (! th->p_terminated) {
/* Register extrication interface */
__pthread_set_own_extricate_if(self, &extr);
if (!(THREAD_GETMEM(self, p_canceled)
&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
th->p_joining = self;
else
already_canceled = 1;
__pthread_unlock(&handle->h_lock);
if (already_canceled) {
__pthread_set_own_extricate_if(self, 0);
__pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
}
suspend(self);
/* Deregister extrication interface */
__pthread_set_own_extricate_if(self, 0);
/* This is a cancellation point */
if (THREAD_GETMEM(self, p_woken_by_cancel)
&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
THREAD_SETMEM(self, p_woken_by_cancel, 0);
__pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
}
__pthread_lock(&handle->h_lock, self);
}
/* Get return value */
if (thread_return != NULL) *thread_return = th->p_retval;
__pthread_unlock(&handle->h_lock);
/* Send notification to thread manager */
if (__pthread_manager_request >= 0) {
request.req_thread = self;
request.req_kind = REQ_FREE;
request.req_args.free.thread_id = thread_id;
TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
(char *) &request, sizeof(request)));
}
return 0;
}
int pthread_detach(pthread_t thread_id)
{
int terminated;
struct pthread_request request;
pthread_handle handle = thread_handle(thread_id);
pthread_descr th;
__pthread_lock(&handle->h_lock, NULL);
if (nonexisting_handle(handle, thread_id)) {
__pthread_unlock(&handle->h_lock);
return ESRCH;
}
th = handle->h_descr;
/* If already detached, error */
if (th->p_detached) {
__pthread_unlock(&handle->h_lock);
return EINVAL;
}
/* If already joining, don't do anything. */
if (th->p_joining != NULL) {
__pthread_unlock(&handle->h_lock);
return 0;
}
/* Mark as detached */
th->p_detached = 1;
terminated = th->p_terminated;
__pthread_unlock(&handle->h_lock);
/* If already terminated, notify thread manager to reclaim resources */
if (terminated && __pthread_manager_request >= 0) {
request.req_thread = thread_self();
request.req_kind = REQ_FREE;
request.req_args.free.thread_id = thread_id;
TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
(char *) &request, sizeof(request)));
}
return 0;
}
|
