1 files changed, 128 insertions, 0 deletions
diff --git a/nuttx/sched/sem_waitirq.c b/nuttx/sched/sem_waitirq.c
new file mode 100644
index 0000000000..96ab61f445
--- /dev/null
+++ b/nuttx/sched/sem_waitirq.c
@@ -0,0 +1,128 @@
+/************************************************************
+ * sem_waitirq.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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 <sys/types.h>
+#include <sched.h>
+#include <errno.h>
+#include <nuttx/arch.h>
+#include "sem_internal.h"
+
+/************************************************************
+ * Compilation Switches
+ ************************************************************/
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Type Declarations
+ ************************************************************/
+
+/************************************************************
+ * Global Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Functions
+ ************************************************************/
+
+/************************************************************
+ * Public Functions
+ ************************************************************/
+
+/************************************************************
+ * Function:  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 semphare, but has received a signal instead.
+ *
+ * Return Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ************************************************************/
+
+void sem_waitirq (_TCB *wtcb)
+{
+  uint32 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)
+    {
+      /* Indicate that the semaphore wait is over. */
+
+      wtcb->waitsem = NULL;
+
+      /* Mark the errno value for the thread. */
+
+      wtcb->errno = EINTR;
+
+      /* Restart the the task. */
+
+      up_unblock_task(wtcb);
+    }
+
+  /* Interrupts may now be enabled. */
+
+  irqrestore(saved_state);
+}