1 files changed, 114 insertions, 0 deletions
diff --git a/libpthread/nptl/pthread_join.c b/libpthread/nptl/pthread_join.c
new file mode 100644
index 000000000..ce6cf6fb9
--- /dev/null
+++ b/libpthread/nptl/pthread_join.c
@@ -0,0 +1,114 @@
+/* Copyright (C) 2002, 2003, 2005, 2006 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
+#include <stdlib.h>
+
+#include <atomic.h>
+#include "pthreadP.h"
+
+
+static void
+cleanup (void *arg)
+{
+  /* If we already changed the waiter ID, reset it.  The call cannot
+     fail for any reason but the thread not having done that yet so
+     there is no reason for a loop.  */
+  (void) atomic_compare_and_exchange_bool_acq ((struct pthread **) arg, NULL,
+					       THREAD_SELF);
+}
+
+
+int
+pthread_join (
+     pthread_t threadid,
+     void **thread_return)
+{
+  struct pthread *pd = (struct pthread *) threadid;
+
+  /* Make sure the descriptor is valid.  */
+  if (INVALID_NOT_TERMINATED_TD_P (pd))
+    /* Not a valid thread handle.  */
+    return ESRCH;
+
+  /* Is the thread joinable?.  */
+  if (IS_DETACHED (pd))
+    /* We cannot wait for the thread.  */
+    return EINVAL;
+
+  struct pthread *self = THREAD_SELF;
+  int result = 0;
+
+  /* During the wait we change to asynchronous cancellation.  If we
+     are canceled the thread we are waiting for must be marked as
+     un-wait-ed for again.  */
+  pthread_cleanup_push (cleanup, &pd->joinid);
+
+  /* Switch to asynchronous cancellation.  */
+  int oldtype = CANCEL_ASYNC ();
+
+  if ((pd == self
+       || (self->joinid == pd
+	   && (pd->cancelhandling
+	       & (CANCELING_BITMASK | CANCELED_BITMASK | EXITING_BITMASK
+		  | TERMINATED_BITMASK)) == 0))
+      && !CANCEL_ENABLED_AND_CANCELED (self->cancelhandling))
+    /* This is a deadlock situation.  The threads are waiting for each
+       other to finish.  Note that this is a "may" error.  To be 100%
+       sure we catch this error we would have to lock the data
+       structures but it is not necessary.  In the unlikely case that
+       two threads are really caught in this situation they will
+       deadlock.  It is the programmer's problem to figure this
+       out.  */
+    result = EDEADLK;
+  /* Wait for the thread to finish.  If it is already locked something
+     is wrong.  There can only be one waiter.  */
+  else if (__builtin_expect (atomic_compare_and_exchange_bool_acq (&pd->joinid,
+								   self,
+								   NULL), 0))
+    /* There is already somebody waiting for the thread.  */
+    result = EINVAL;
+  else
+    /* Wait for the child.  */
+    lll_wait_tid (pd->tid);
+
+
+  /* Restore cancellation mode.  */
+  CANCEL_RESET (oldtype);
+
+  /* Remove the handler.  */
+  pthread_cleanup_pop (0);
+
+
+  if (__builtin_expect (result == 0, 1))
+    {
+      /* We mark the thread as terminated and as joined.  */
+      pd->tid = -1;
+
+      /* Store the return value if the caller is interested.  */
+      if (thread_return != NULL)
+	*thread_return = pd->result;
+
+
+      /* Free the TCB.  */
+      __free_tcb (pd);
+    }
+
+  return result;
+}