1 files changed, 145 insertions, 0 deletions
diff --git a/nuttx/sched/sem_waitirq.c b/nuttx/sched/sem_waitirq.c
new file mode 100644
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+/****************************************************************************
+ * sched/sem_waitirq.c
+ *
+ *   Copyright (C) 2007-2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sched.h>
+#include <errno.h>
+#include <nuttx/arch.h>
+
+#include "sem_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sem_waitirq
+ *
+ * Description:
+ *   This function is called when a signal is received by a task that is
+ *   waiting on a semaphore.  According to the POSIX spec, "...the calling
+ *   thread shall not return from the call to [sem_wait] until it either
+ *   locks the semaphore or the call is interrupted by a signal."
+ *
+ * Parameters:
+ *   wtcb    - A pointer to the TCB of the task that is waiting on a
+ *             semphaphore, but has received a signal or timeout instead.
+ *   errcode - EINTR if the semaphore wait was awakened by a signal;
+ *             ETIMEDOUT if awakened by a timeout
+ *
+ * Return Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+void sem_waitirq(FAR _TCB *wtcb, int errcode)
+{
+  irqstate_t saved_state;
+
+  /* Disable interrupts.  This is necessary (unfortunately) because an
+   * interrupt handler may attempt to post the semaphore while we are
+   * doing this.
+   */
+
+  saved_state = irqsave();
+
+  /* It is possible that an interrupt/context switch beat us to the punch
+   * and already changed the task's state.
+   */
+
+  if (wtcb->task_state == TSTATE_WAIT_SEM)
+    {
+      sem_t *sem = wtcb->waitsem;
+      DEBUGASSERT(sem != NULL && sem->semcount < 0);
+
+      /* Restore the correct priority of all threads that hold references
+       * to this semaphore.
+       */
+
+      sem_canceled(wtcb, sem);
+
+      /* And increment the count on the semaphore.  This releases the count
+       * that was taken by sem_post().  This count decremented the semaphore
+       * count to negative and caused the thread to be blocked in the first
+       * place.
+       */ 
+
+      sem->semcount++;
+
+      /* Indicate that the semaphore wait is over. */
+
+      wtcb->waitsem = NULL;
+
+      /* Mark the errno value for the thread. */
+
+      wtcb->pterrno = errcode;
+
+      /* Restart the task. */
+
+      up_unblock_task(wtcb);
+    }
+
+  /* Interrupts may now be enabled. */
+
+  irqrestore(saved_state);
+}
+