Resync new repository with old repo r5166

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5153 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 166 insertions, 0 deletions

diff --git a/nuttx/sched/mq_receive.c b/nuttx/sched/mq_receive.c
new file mode 100644
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+/************************************************************************
+ * sched/mq_receive.c
+ *
+ *   Copyright (C) 2007, 2009 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 <sys/types.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <mqueue.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "mq_internal.h"
+
+/************************************************************************
+ * Pre-processor Definitions
+ ************************************************************************/
+
+/************************************************************************
+ * Private Type Declarations
+ ************************************************************************/
+
+/************************************************************************
+ * Global Variables
+ ************************************************************************/
+
+/************************************************************************
+ * Private Variables
+ ************************************************************************/
+
+/************************************************************************
+ * Private Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Public Functions
+ ************************************************************************/
+
+/************************************************************************
+ * Name: mq_receive
+ *
+ * Description:
+ *   This function receives the oldest of the highest priority messages
+ *   from the message queue specified by "mqdes."  If the size of the
+ *   buffer in bytes (msglen) is less than the "mq_msgsize" attribute of
+ *   the message queue, mq_receive will return an error.  Otherwise, the
+ *   selected message is removed from the queue and copied to "msg."
+ *
+ *   If the message queue is empty and O_NONBLOCK was not set,
+ *   mq_receive() will block until a message is added to the message
+ *   queue.  If more than one task is waiting to receive a message, only
+ *   the task with the highest priority that has waited the longest will
+ *   be unblocked.
+ *
+ *   If the queue is empty and O_NONBLOCK is set, ERROR will be returned.
+ *
+ * Parameters:
+ *   mqdes - Message Queue Descriptor
+ *   msg - Buffer to receive the message
+ *   msglen - Size of the buffer in bytes
+ *   prio - If not NULL, the location to store message priority.
+ *
+ * Return Value:
+ *   One success, the length of the selected message in bytes is returned.
+ *   On failure, -1 (ERROR) is returned and the errno is set appropriately:
+ *
+ *   EAGAIN   The queue was empty, and the O_NONBLOCK flag was set
+ *            for the message queue description referred to by 'mqdes'.
+ *   EPERM    Message queue opened not opened for reading.
+ *   EMSGSIZE 'msglen' was less than the maxmsgsize attribute of the
+ *            message queue.
+ *   EINTR    The call was interrupted by a signal handler.
+ *   EINVAL   Invalid 'msg' or 'mqdes'
+ *
+ * Assumptions:
+ *
+ ************************************************************************/
+
+ssize_t mq_receive(mqd_t mqdes, void *msg, size_t msglen, int *prio)
+{
+  FAR mqmsg_t *mqmsg;
+  irqstate_t   saved_state;
+  ssize_t      ret = ERROR;
+
+  DEBUGASSERT(up_interrupt_context() == false);
+
+  /* Verify the input parameters and, in case of an error, set
+   * errno appropriately.
+   */
+
+  if (mq_verifyreceive(mqdes, msg, msglen) != OK)
+    {
+      return ERROR;
+    }
+
+  /* Get the next mesage from the message queue.  We will disable
+   * pre-emption until we have completed the message received.  This
+   * is not too bad because if the receipt takes a long time, it will
+   * be because we are blocked waiting for a message and pre-emption
+   * will be re-enabled while we are blocked
+   */
+
+  sched_lock();
+
+  /* Furthermore, mq_waitreceive() expects to have interrupts disabled
+   * because messages can be sent from interrupt level.
+   */
+
+  saved_state = irqsave();
+
+  /* Get the message from the message queue */
+
+  mqmsg = mq_waitreceive(mqdes);
+  irqrestore(saved_state);
+
+  /* Check if we got a message from the message queue.  We might
+   * not have a message if:
+   *
+   * - The message queue is empty and O_NONBLOCK is set in the mqdes
+   * - The wait was interrupted by a signal
+   */
+
+  if (mqmsg)
+    {
+      ret = mq_doreceive(mqdes, mqmsg, msg, prio);
+    }
+
+  sched_unlock();
+  return ret;
+}