Added new routines from POSIX 1003.1j. This is alpha level code.

        * spin.c: New module implementing spin locks.
        * barrier.c: New module implementing barriers.
        * pthread.h (_POSIX_SPIN_LOCKS): defined.
        (_POSIX_BARRIERS): Defined.
        (pthread_spin_*): Defined.
        (pthread_barrier*): Defined.
        (PTHREAD_BARRIER_SERIAL_THREAD): Defined.
        * implement.h (pthread_spinlock_t_): Defined.
        (pthread_barrier_t_): Defined.
        (pthread_barrierattr_t_): Defined.

        * mutex.c (pthread_mutex_lock): Return with the error
        if an auto-initialiser initialisation fails.

        * nonportable.c (pthread_getprocessors_np): New; gets the
        number of available processors for the current process.

1 files changed, 517 insertions, 0 deletions

diff --git a/barrier.c b/barrier.c
new file mode 100644
index 0000000..4495e33
--- /dev/null
+++ b/barrier.c
@@ -0,0 +1,517 @@
+/*
+ * barrier.c
+ *
+ * Description:
+ * This translation unit implements spin locks primitives.
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright (C) 1998
+ *
+ * This library 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 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA
+ */
+
+#include "pthread.h"
+#include "implement.h"
+
+
+static int
+ptw32_barrier_check_need_init(pthread_barrier_t *barrier)
+{
+  int result = 0;
+
+  /*
+   * The following guarded test is specifically for statically
+   * initialised barriers (via PTHREAD_BARRIER_INITIALIZER).
+   *
+   * Note that by not providing this synchronisation we risk
+   * introducing race conditions into applications which are
+   * correctly written.
+   *
+   * Approach
+   * --------
+   * We know that static barriers will not be PROCESS_SHARED
+   * so we can serialise access to internal state using
+   * Win32 Critical Sections rather than Win32 Mutexes.
+   *
+   * If using a single global lock slows applications down too much,
+   * multiple global locks could be created and hashed on some random
+   * value associated with each barrier, the pointer perhaps. At a guess,
+   * a good value for the optimal number of global locks might be
+   * the number of processors + 1.
+   *
+   */
+  EnterCriticalSection(&ptw32_barrier_test_init_lock);
+
+  /*
+   * We got here possibly under race
+   * conditions. Check again inside the critical section
+   * and only initialise if the barrier is valid (not been destroyed).
+   * If a static barrier has been destroyed, the application can
+   * re-initialise it only by calling pthread_barrier_init()
+   * explicitly.
+   */
+  if (*barrier == (pthread_barrier_t) PTW32_OBJECT_AUTO_INIT)
+    {
+      result = pthread_barrier_init(barrier, NULL);
+    }
+  else if (*barrier == NULL)
+    {
+      /*
+       * The barrier has been destroyed while we were waiting to
+       * initialise it, so the operation that caused the
+       * auto-initialisation should fail.
+       */
+      result = EINVAL;
+    }
+
+  LeaveCriticalSection(&ptw32_barrier_test_init_lock);
+
+  return(result);
+}
+
+
+int
+pthread_barrier_init(pthread_barrier_t * barrier,
+                     const pthread_barrierattr_t * attr,
+                     int count)
+{
+  int result = 0;
+  int pshared = PTHREAD_PROCESS_PRIVATE;
+  pthread_barrier_t * b;
+
+  if (barrier == NULL)
+    {
+      return EINVAL;
+    }
+
+  b = (pthread_barrier_t *) calloc(1, sizeof(*b));
+
+  if (b == NULL)
+    {
+      result = ENOMEM;
+      goto FAIL0;
+    }
+
+  if (attr != NULL && *attr != NULL)
+    {
+      pshared = (*attr)->pshared;
+    }
+
+  b->nCurrentBarrierHeight = b->nInitialBarrierHeight = count;
+
+  result = pthread_mutex_init(&b->mtxExclusiveAccess, NULL);
+  if (0 != result)
+    {
+      goto FAIL0;
+    }
+
+  result = sem_init(&(b->semBarrierBreeched), pshared, 0);
+  if (0 != result)
+    {
+      goto FAIL1;
+    }
+
+  goto DONE;
+
+ FAIL1:
+  (void) pthread_mutex_destroy(&b->mtxExclusiveAccess);
+
+ FAIL0:
+  (void) free(b);
+
+ DONE:
+  return(result);
+}
+
+int
+pthread_barrier_destroy(pthread_barrier_t *barrier)
+{
+  int result = 0;
+  pthread_barrier_t b;
+
+  if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID)
+    {
+      return EINVAL;
+    }
+
+  if (*barrier != (pthread_barrier_t) PTW32_OBJECT_AUTO_INIT)
+    {
+      b = *barrier;
+  
+      if (0 == pthread_mutex_trylock(&b->mtxExclusiveAccess))
+        {
+          /*
+           * FIXME!!!
+           * The mutex isn't held by another thread but we could still
+           * be too late invalidating the barrier below since another thread
+           * may alredy have entered barrier_wait and the check for a valid
+           * *barrier != NULL.
+           */
+          *barrier = NULL;
+
+          (void) sem_destroy(&(b->semBarrierBreeched));
+          (void) pthread_mutex_unlock(&(b->mtxExclusiveAccess));
+          (void) pthread_mutex_destroy(&(b->mtxExclusiveAccess));
+          (void) free(b);
+        }
+    }
+  else
+    {
+      /*
+       * See notes in ptw32_barrier_check_need_init() above also.
+       */
+      EnterCriticalSection(&ptw32_barrier_test_init_lock);
+
+      /*
+       * Check again.
+       */
+      if (*barrier == (pthread_barrier_t) PTW32_OBJECT_AUTO_INIT)
+        {
+          /*
+           * This is all we need to do to destroy a statically
+           * initialised barrier that has not yet been used (initialised).
+           * If we get to here, another thread
+           * waiting to initialise this barrier will get an EINVAL.
+           */
+          *barrier = NULL;
+        }
+      else
+        {
+          /*
+           * The barrier has been initialised while we were waiting
+           * so assume it's in use.
+           */
+          result = EBUSY;
+        }
+
+      LeaveCriticalSection(&ptw32_barrier_test_init_lock);
+    }
+
+  return(result);
+}
+
+
+int
+pthread_barrier_wait(pthread_barrier_t *barrier)
+{
+  int result;
+  pthread_barrier_t b;
+
+  if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID)
+    {
+      return EINVAL;
+    }
+
+  if (*barrier == (pthread_barrier_t) PTHREAD_OBJECT_AUTO_INIT)
+    {
+      if ((result = ptw32_barrier_check_need_init(barrier)) != 0)
+        {
+          return(result);
+        }
+    }
+
+  b = *barrier;
+
+  result = pthread_mutex_lock(b->mtxExclusiveAccess);
+  if (0 == result)
+    {
+      if (0 == --(b->nCurrentBarrierHeight))
+        {
+          b->nCurrentBarrierHeight = b->nInitialBarrierHeight;
+          (void) pthread_mutex_unlock(b->mtxExclusiveAccess);
+          (void) sem_post_multiple(&(b->semBarrierBreeched),
+                                   b->InitialBarrierHeight);
+          /*
+           * Would be better if the first thread to return
+           * from this routine got this value. On a single
+           * processor machine that will be the last thread
+           * to reach the barrier (us), most of the time.
+           */
+          result = PTHREAD_BARRIER_SERIAL_THREAD;
+        }
+      else
+        {
+          /*
+           * pthread_barrier_wait() is not a cancelation point
+           * so temporarily prevent sem_wait() from being one.
+           */
+          pthread_t self = pthread_self();
+          int cancelType = pthread_getcanceltype(self);
+          int oldCancelState;
+
+          if (cancelType == PTHREAD_CANCEL_DEFERRED)
+            {
+              oldCancelState = pthread_setcancelstate(self,
+                                                      PTHREAD_CANCEL_DISABLED);
+            }
+
+          /* Could still be PTHREAD_CANCEL_ASYNCHRONOUS. */
+          pthread_cleanup_push(pthread_mutex_unlock,
+                               (void *) &(b->mtxExclusiveAccess));
+
+          if (0 != sem_wait(&(b->semBarrierBreeched)))
+            {
+              result = errno;
+            }
+
+          if (cancelType == PTHREAD_CANCEL_DEFERRED)
+            {
+              pthread_setcancelstate(self, oldCancelState);
+            }
+
+          pthread_cleanup_pop(1);
+        }
+    }
+
+  return(result);
+}
+
+
+int
+pthread_barrierattr_init (pthread_barrierattr_t * attr)
+     /*
+      * ------------------------------------------------------
+      * DOCPUBLIC
+      *      Initializes a barrier attributes object with default
+      *      attributes.
+      *
+      * PARAMETERS
+      *      attr
+      *              pointer to an instance of pthread_barrierattr_t
+      *
+      *
+      * DESCRIPTION
+      *      Initializes a barrier attributes object with default
+      *      attributes.
+      *
+      *      NOTES:
+      *              1)      Used to define barrier types
+      *
+      * RESULTS
+      *              0               successfully initialized attr,
+      *              ENOMEM          insufficient memory for attr.
+      *
+      * ------------------------------------------------------
+      */
+{
+  pthread_barrierattr_t ba;
+  int result = 0;
+ 
+  ba = (pthread_barrierattr_t) calloc (1, sizeof (*ba));
+ 
+  if (ba == NULL)
+    {
+      result = ENOMEM;
+    }
+ 
+  ba->pshared = PTHREAD_PROCESS_PRIVATE;
+ 
+  *attr = ba;
+ 
+  return (result);
+ 
+}                               /* pthread_barrierattr_init */
+ 
+ 
+int
+pthread_barrierattr_destroy (pthread_barrierattr_t * attr)
+     /*
+      * ------------------------------------------------------
+      * DOCPUBLIC
+      *      Destroys a barrier attributes object. The object can
+      *      no longer be used.
+      *
+      * PARAMETERS
+      *      attr
+      *              pointer to an instance of pthread_barrierattr_t
+      *
+      *
+      * DESCRIPTION
+      *      Destroys a barrier attributes object. The object can
+      *      no longer be used.
+      *
+      *      NOTES:
+      *              1)      Does not affect barrieres created using 'attr'
+      *
+      * RESULTS
+      *              0               successfully released attr,
+      *              EINVAL          'attr' is invalid.
+      *
+      * ------------------------------------------------------
+      */
+{
+  int result = 0;
+ 
+  if (attr == NULL || *attr == NULL)
+    {
+      result = EINVAL;
+    }
+  else
+    {
+      pthread_barrierattr_t ba = *attr;
+ 
+      *attr = NULL;
+      free (ba);
+ 
+      result = 0;
+    }
+ 
+  return (result);
+ 
+}                               /* pthread_barrierattr_destroy */
+
+
+int
+pthread_barrierattr_getpshared (const pthread_barrierattr_t * attr,
+                                int *pshared)
+     /*
+      * ------------------------------------------------------
+      * DOCPUBLIC
+      *      Determine whether barriers created with 'attr' can be
+      *      shared between processes.
+      *
+      * PARAMETERS
+      *      attr
+      *              pointer to an instance of pthread_barrierattr_t
+      *
+      *      pshared
+      *              will be set to one of:
+      *
+      *                      PTHREAD_PROCESS_SHARED
+      *                              May be shared if in shared memory
+      *
+      *                      PTHREAD_PROCESS_PRIVATE
+      *                              Cannot be shared.
+      *
+      *
+      * DESCRIPTION
+      *      Mutexes creatd with 'attr' can be shared between
+      *      processes if pthread_barrier_t variable is allocated
+      *      in memory shared by these processes.
+      *      NOTES:
+      *              1)      pshared barriers MUST be allocated in shared
+      *                      memory.
+      *              2)      The following macro is defined if shared barriers
+      *                      are supported:
+      *                              _POSIX_THREAD_PROCESS_SHARED
+      *
+      * RESULTS
+      *              0               successfully retrieved attribute,
+      *              EINVAL          'attr' is invalid,
+      *
+      * ------------------------------------------------------
+      */
+{
+  int result;
+ 
+  if ((attr != NULL && *attr != NULL) &&
+      (pshared != NULL))
+    {
+      *pshared = (*attr)->pshared;
+      result = 0;
+    }
+  else
+    {
+      *pshared = PTHREAD_PROCESS_PRIVATE;
+      result = EINVAL;
+    }
+ 
+  return (result);
+ 
+}                               /* pthread_barrierattr_getpshared */
+
+
+int
+pthread_barrierattr_setpshared (pthread_barrierattr_t * attr,
+                                int pshared)
+     /*
+      * ------------------------------------------------------
+      * DOCPUBLIC
+      *      Barriers created with 'attr' can be shared between
+      *      processes if pthread_barrier_t variable is allocated
+      *      in memory shared by these processes.
+      *
+      * PARAMETERS
+      *      attr
+      *              pointer to an instance of pthread_barrierattr_t
+      *
+      *      pshared
+      *              must be one of:
+      *
+      *                      PTHREAD_PROCESS_SHARED
+      *                              May be shared if in shared memory
+      *
+      *                      PTHREAD_PROCESS_PRIVATE
+      *                              Cannot be shared.
+      *
+      * DESCRIPTION
+      *      Mutexes creatd with 'attr' can be shared between
+      *      processes if pthread_barrier_t variable is allocated
+      *      in memory shared by these processes.
+      *
+      *      NOTES:
+      *              1)      pshared barriers MUST be allocated in shared
+      *                      memory.
+      *
+      *              2)      The following macro is defined if shared barriers
+      *                      are supported:
+      *                              _POSIX_THREAD_PROCESS_SHARED
+      *
+      * RESULTS
+      *              0               successfully set attribute,
+      *              EINVAL          'attr' or pshared is invalid,
+      *              ENOSYS          PTHREAD_PROCESS_SHARED not supported,
+      *
+      * ------------------------------------------------------
+      */
+{
+  int result;
+ 
+  if ((attr != NULL && *attr != NULL) &&
+      ((pshared == PTHREAD_PROCESS_SHARED) ||
+       (pshared == PTHREAD_PROCESS_PRIVATE)))
+    {
+      if (pshared == PTHREAD_PROCESS_SHARED)
+        {
+ 
+#if !defined( _POSIX_THREAD_PROCESS_SHARED )
+ 
+          result = ENOSYS;
+          pshared = PTHREAD_PROCESS_PRIVATE;
+ 
+#else
+ 
+          result = 0;
+ 
+#endif /* _POSIX_THREAD_PROCESS_SHARED */
+ 
+        }
+      else
+        {
+          result = 0;
+        }
+ 
+      (*attr)->pshared = pshared;
+    }
+  else
+    {
+      result = EINVAL;
+    }
+ 
+  return (result);
+ 
+}                               /* pthread_barrierattr_setpshared */
+