.

1 files changed, 191 insertions, 0 deletions

diff --git a/nptl/sysdeps/pthread/pthread_cond_wait.c b/nptl/sysdeps/pthread/pthread_cond_wait.c
new file mode 100644
index 0000000000..f5f5cec5a8
--- /dev/null
+++ b/nptl/sysdeps/pthread/pthread_cond_wait.c
@@ -0,0 +1,191 @@
+/* Copyright (C) 2003, 2004, 2006 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
+
+   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 <endian.h>
+#include <errno.h>
+#include <sysdep.h>
+#include <lowlevellock.h>
+#include <pthread.h>
+#include <pthreadP.h>
+
+#include <shlib-compat.h>
+
+
+struct _condvar_cleanup_buffer
+{
+  int oldtype;
+  pthread_cond_t *cond;
+  pthread_mutex_t *mutex;
+  unsigned int bc_seq;
+};
+
+
+void
+__attribute__ ((visibility ("hidden")))
+__condvar_cleanup (void *arg)
+{
+  struct _condvar_cleanup_buffer *cbuffer =
+    (struct _condvar_cleanup_buffer *) arg;
+  unsigned int destroying;
+
+  /* We are going to modify shared data.  */
+  lll_mutex_lock (cbuffer->cond->__data.__lock);
+
+  if (cbuffer->bc_seq == cbuffer->cond->__data.__broadcast_seq)
+    {
+      /* This thread is not waiting anymore.  Adjust the sequence counters
+	 appropriately.  We do not increment WAKEUP_SEQ if this would
+	 bump it over the value of TOTAL_SEQ.  This can happen if a thread
+	 was woken and then canceled.  */
+      if (cbuffer->cond->__data.__wakeup_seq
+	  < cbuffer->cond->__data.__total_seq)
+	{
+	  ++cbuffer->cond->__data.__wakeup_seq;
+	  ++cbuffer->cond->__data.__futex;
+	}
+      ++cbuffer->cond->__data.__woken_seq;
+    }
+
+  cbuffer->cond->__data.__nwaiters -= 1 << COND_CLOCK_BITS;
+
+  /* If pthread_cond_destroy was called on this variable already,
+     notify the pthread_cond_destroy caller all waiters have left
+     and it can be successfully destroyed.  */
+  destroying = 0;
+  if (cbuffer->cond->__data.__total_seq == -1ULL
+      && cbuffer->cond->__data.__nwaiters < (1 << COND_CLOCK_BITS))
+    {
+      lll_futex_wake (&cbuffer->cond->__data.__nwaiters, 1);
+      destroying = 1;
+    }
+
+  /* We are done.  */
+  lll_mutex_unlock (cbuffer->cond->__data.__lock);
+
+  /* Wake everybody to make sure no condvar signal gets lost.  */
+  if (! destroying)
+    lll_futex_wake (&cbuffer->cond->__data.__futex, INT_MAX);
+
+  /* Get the mutex before returning unless asynchronous cancellation
+     is in effect.  */
+  __pthread_mutex_cond_lock (cbuffer->mutex);
+}
+
+
+int
+__pthread_cond_wait (cond, mutex)
+     pthread_cond_t *cond;
+     pthread_mutex_t *mutex;
+{
+  struct _pthread_cleanup_buffer buffer;
+  struct _condvar_cleanup_buffer cbuffer;
+  int err;
+
+  /* Make sure we are along.  */
+  lll_mutex_lock (cond->__data.__lock);
+
+  /* Now we can release the mutex.  */
+  err = __pthread_mutex_unlock_usercnt (mutex, 0);
+  if (__builtin_expect (err, 0))
+    {
+      lll_mutex_unlock (cond->__data.__lock);
+      return err;
+    }
+
+  /* We have one new user of the condvar.  */
+  ++cond->__data.__total_seq;
+  ++cond->__data.__futex;
+  cond->__data.__nwaiters += 1 << COND_CLOCK_BITS;
+
+  /* Remember the mutex we are using here.  If there is already a
+     different address store this is a bad user bug.  Do not store
+     anything for pshared condvars.  */
+  if (cond->__data.__mutex != (void *) ~0l)
+    cond->__data.__mutex = mutex;
+
+  /* Prepare structure passed to cancellation handler.  */
+  cbuffer.cond = cond;
+  cbuffer.mutex = mutex;
+
+  /* Before we block we enable cancellation.  Therefore we have to
+     install a cancellation handler.  */
+  __pthread_cleanup_push (&buffer, __condvar_cleanup, &cbuffer);
+
+  /* The current values of the wakeup counter.  The "woken" counter
+     must exceed this value.  */
+  unsigned long long int val;
+  unsigned long long int seq;
+  val = seq = cond->__data.__wakeup_seq;
+  /* Remember the broadcast counter.  */
+  cbuffer.bc_seq = cond->__data.__broadcast_seq;
+
+  do
+    {
+      unsigned int futex_val = cond->__data.__futex;
+
+      /* Prepare to wait.  Release the condvar futex.  */
+      lll_mutex_unlock (cond->__data.__lock);
+
+      /* Enable asynchronous cancellation.  Required by the standard.  */
+      cbuffer.oldtype = __pthread_enable_asynccancel ();
+
+      /* Wait until woken by signal or broadcast.  */
+      lll_futex_wait (&cond->__data.__futex, futex_val);
+
+      /* Disable asynchronous cancellation.  */
+      __pthread_disable_asynccancel (cbuffer.oldtype);
+
+      /* We are going to look at shared data again, so get the lock.  */
+      lll_mutex_lock (cond->__data.__lock);
+
+      /* If a broadcast happened, we are done.  */
+      if (cbuffer.bc_seq != cond->__data.__broadcast_seq)
+	goto bc_out;
+
+      /* Check whether we are eligible for wakeup.  */
+      val = cond->__data.__wakeup_seq;
+    }
+  while (val == seq || cond->__data.__woken_seq == val);
+
+  /* Another thread woken up.  */
+  ++cond->__data.__woken_seq;
+
+ bc_out:
+
+  cond->__data.__nwaiters -= 1 << COND_CLOCK_BITS;
+
+  /* If pthread_cond_destroy was called on this varaible already,
+     notify the pthread_cond_destroy caller all waiters have left
+     and it can be successfully destroyed.  */
+  if (cond->__data.__total_seq == -1ULL
+      && cond->__data.__nwaiters < (1 << COND_CLOCK_BITS))
+    lll_futex_wake (&cond->__data.__nwaiters, 1);
+
+  /* We are done with the condvar.  */
+  lll_mutex_unlock (cond->__data.__lock);
+
+  /* The cancellation handling is back to normal, remove the handler.  */
+  __pthread_cleanup_pop (&buffer, 0);
+
+  /* Get the mutex before returning.  */
+  return __pthread_mutex_cond_lock (mutex);
+}
+
+versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
+		  GLIBC_2_3_2);