summaryrefslogtreecommitdiff
path: root/linuxthreads/join.c
blob: 42eb033746f659ec2374595719af1e151c2d48e5 (plain)
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
/* 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 <unistd.h>
#include "pthread.h"
#include "internals.h"
#include "spinlock.h"
#include "restart.h"

void pthread_exit(void * retval)
{
  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();
  __pthread_destroy_specifics();
  /* Store return value */
  __pthread_lock(THREAD_GETMEM(self, p_lock), self);
  THREAD_SETMEM(self, p_retval, retval);
  /* 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;
    __libc_write(__pthread_manager_request, (char *)&request, sizeof(request));
    suspend(self);
  }
  /* Exit the process (but don't flush stdio streams, and don't run
     atexit functions). */
  _exit(0);
}

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_lock(&handle->h_lock, self);
  if (invalid_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) {
    th->p_joining = self;
    __pthread_unlock(&handle->h_lock);
    suspend_with_cancellation(self);
    /* This is a cancellation point */
    if (THREAD_GETMEM(self, p_canceled)
	&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
      th->p_joining = NULL;
      pthread_exit(PTHREAD_CANCELED);
    }
    __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;
    __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 (invalid_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;
    __libc_write(__pthread_manager_request,
		 (char *) &request, sizeof(request));
  }
  return 0;
}