(pthread_exit): main thread now calls exit() instead of _exit() in
[kopensolaris-gnu/glibc.git] / linuxthreads / join.c
1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
2 /* threads for Linux.                                                   */
3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
4 /*                                                                      */
5 /* This program is free software; you can redistribute it and/or        */
6 /* modify it under the terms of the GNU Library General Public License  */
7 /* as published by the Free Software Foundation; either version 2       */
8 /* of the License, or (at your option) any later version.               */
9 /*                                                                      */
10 /* This program 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        */
13 /* GNU Library General Public License for more details.                 */
14
15 /* Thread termination and joining */
16
17 #include <errno.h>
18 #include <sched.h>
19 #include <unistd.h>
20 #include "pthread.h"
21 #include "internals.h"
22 #include "spinlock.h"
23 #include "restart.h"
24
25 void pthread_exit(void * retval)
26 {
27   pthread_descr self = thread_self();
28   pthread_descr joining;
29   struct pthread_request request;
30
31   /* Reset the cancellation flag to avoid looping if the cleanup handlers
32      contain cancellation points */
33   THREAD_SETMEM(self, p_canceled, 0);
34   /* Call cleanup functions and destroy the thread-specific data */
35   __pthread_perform_cleanup();
36   __pthread_destroy_specifics();
37   /* Store return value */
38   __pthread_lock(THREAD_GETMEM(self, p_lock), self);
39   THREAD_SETMEM(self, p_retval, retval);
40   /* See whether we have to signal the death.  */
41   if (THREAD_GETMEM(self, p_report_events))
42     {
43       /* See whether TD_DEATH is in any of the mask.  */
44       int idx = __td_eventword (TD_DEATH);
45       uint32_t mask = __td_eventmask (TD_DEATH);
46
47       if ((mask & (__pthread_threads_events.event_bits[idx]
48                    | THREAD_GETMEM_NC(self,
49                                       p_eventbuf.eventmask.event_bits[idx])))
50           != 0)
51         {
52           /* Yep, we have to signal the death.  */
53           THREAD_SETMEM(self, p_eventbuf.eventnum, TD_DEATH);
54           THREAD_SETMEM(self, p_eventbuf.eventdata, self);
55           __pthread_last_event = self;
56
57           /* Now call the function to signal the event.  */
58           __linuxthreads_death_event();
59         }
60     }
61   /* Say that we've terminated */
62   THREAD_SETMEM(self, p_terminated, 1);
63   /* See if someone is joining on us */
64   joining = THREAD_GETMEM(self, p_joining);
65   __pthread_spin_unlock(THREAD_GETMEM(self, p_lock));
66   /* Restart joining thread if any */
67   if (joining != NULL) restart(joining);
68   /* If this is the initial thread, block until all threads have terminated.
69      If another thread calls exit, we'll be terminated from our signal
70      handler. */
71   if (self == __pthread_main_thread && __pthread_manager_request >= 0) {
72     request.req_thread = self;
73     request.req_kind = REQ_MAIN_THREAD_EXIT;
74     __libc_write(__pthread_manager_request, (char *)&request, sizeof(request));
75     suspend(self);
76     /* Main thread flushes stdio streams and runs atexit functions.
77        It also calls a handler within LinuxThreads which sends a process exit
78        request to the thread manager. */
79     exit(0); 
80   }
81   /* Threads other than the main one  terminate without flushing stdio streams
82      or running atexit functions. */
83   _exit(0);
84 }
85
86 /* Function called by pthread_cancel to remove the thread from
87    waiting on a condition variable queue. */
88
89 static int join_extricate_func(void *obj, pthread_descr th)
90 {
91   volatile pthread_descr self = thread_self();
92   pthread_handle handle = obj;
93   pthread_descr jo;
94   int did_remove = 0;
95
96   __pthread_lock(&handle->h_lock, self);
97   jo = handle->h_descr;
98   did_remove = jo->p_joining != NULL;
99   jo->p_joining = NULL;
100   __pthread_spin_unlock(&handle->h_lock);
101
102   return did_remove;
103 }
104
105 int pthread_join(pthread_t thread_id, void ** thread_return)
106 {
107   volatile pthread_descr self = thread_self();
108   struct pthread_request request;
109   pthread_handle handle = thread_handle(thread_id);
110   pthread_descr th;
111   pthread_extricate_if extr;
112   int already_canceled = 0;
113
114   /* Set up extrication interface */
115   extr.pu_object = handle;
116   extr.pu_extricate_func = join_extricate_func;
117
118   __pthread_lock(&handle->h_lock, self);
119   if (invalid_handle(handle, thread_id)) {
120     __pthread_spin_unlock(&handle->h_lock);
121     return ESRCH;
122   }
123   th = handle->h_descr;
124   if (th == self) {
125     __pthread_spin_unlock(&handle->h_lock);
126     return EDEADLK;
127   }
128   /* If detached or already joined, error */
129   if (th->p_detached || th->p_joining != NULL) {
130     __pthread_spin_unlock(&handle->h_lock);
131     return EINVAL;
132   }
133   /* If not terminated yet, suspend ourselves. */
134   if (! th->p_terminated) {
135     /* Register extrication interface */
136     __pthread_set_own_extricate_if(self, &extr);
137     if (!(THREAD_GETMEM(self, p_canceled)
138         && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
139       th->p_joining = self;
140     else
141       already_canceled = 1;
142     __pthread_spin_unlock(&handle->h_lock);
143
144     if (already_canceled) {
145       __pthread_set_own_extricate_if(self, 0);
146       pthread_exit(PTHREAD_CANCELED);
147     }
148
149     suspend(self);
150     /* Deregister extrication interface */
151     __pthread_set_own_extricate_if(self, 0);
152
153     /* This is a cancellation point */
154     if (THREAD_GETMEM(self, p_woken_by_cancel)
155         && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
156       THREAD_SETMEM(self, p_woken_by_cancel, 0);
157       pthread_exit(PTHREAD_CANCELED);
158     }
159     __pthread_lock(&handle->h_lock, self);
160   }
161   /* Get return value */
162   if (thread_return != NULL) *thread_return = th->p_retval;
163   __pthread_spin_unlock(&handle->h_lock);
164   /* Send notification to thread manager */
165   if (__pthread_manager_request >= 0) {
166     request.req_thread = self;
167     request.req_kind = REQ_FREE;
168     request.req_args.free.thread_id = thread_id;
169     __libc_write(__pthread_manager_request,
170                  (char *) &request, sizeof(request));
171   }
172   return 0;
173 }
174
175 int pthread_detach(pthread_t thread_id)
176 {
177   int terminated;
178   struct pthread_request request;
179   pthread_handle handle = thread_handle(thread_id);
180   pthread_descr th;
181
182   __pthread_lock(&handle->h_lock, NULL);
183   if (invalid_handle(handle, thread_id)) {
184     __pthread_spin_unlock(&handle->h_lock);
185     return ESRCH;
186   }
187   th = handle->h_descr;
188   /* If already detached, error */
189   if (th->p_detached) {
190     __pthread_spin_unlock(&handle->h_lock);
191     return EINVAL;
192   }
193   /* If already joining, don't do anything. */
194   if (th->p_joining != NULL) {
195     __pthread_spin_unlock(&handle->h_lock);
196     return 0;
197   }
198   /* Mark as detached */
199   th->p_detached = 1;
200   terminated = th->p_terminated;
201   __pthread_spin_unlock(&handle->h_lock);
202   /* If already terminated, notify thread manager to reclaim resources */
203   if (terminated && __pthread_manager_request >= 0) {
204     request.req_thread = thread_self();
205     request.req_kind = REQ_FREE;
206     request.req_args.free.thread_id = thread_id;
207     __libc_write(__pthread_manager_request,
208                  (char *) &request, sizeof(request));
209   }
210   return 0;
211 }