1 files changed, 312 insertions, 0 deletions
diff --git a/nuttx/sched/mq_rcvinternal.c b/nuttx/sched/mq_rcvinternal.c
new file mode 100644
index 000000000..e80685e87
--- /dev/null
+++ b/nuttx/sched/mq_rcvinternal.c
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+/****************************************************************************
+ * sched/mq_rcvinternal.c
+ *
+ *   Copyright (C) 2007, 2008, 2012 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 <fcntl.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <mqueue.h>
+#include <sched.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "mq_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: mq_verifyreceive
+ *
+ * Description:
+ *   This is internal, common logic shared by both mq_receive and
+ *   mq_timedreceive.  This function verifies the input parameters that are
+ *   common to both functions.
+ *
+ * Parameters:
+ *   mqdes - Message Queue Descriptor
+ *   msg - Buffer to receive the message
+ *   msglen - Size of the buffer in bytes
+ *
+ * Return Value:
+ *   One success, 0 (OK) is returned. On failure, -1 (ERROR) is returned and
+ *   the errno is set appropriately:
+ *
+ *   EPERM    Message queue opened not opened for reading.
+ *   EMSGSIZE 'msglen' was less than the maxmsgsize attribute of the message
+ *            queue.
+ *   EINVAL   Invalid 'msg' or 'mqdes'
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+int mq_verifyreceive(mqd_t mqdes, void *msg, size_t msglen)
+{
+  /* Verify the input parameters */
+
+  if (!msg || !mqdes)
+    {
+      set_errno(EINVAL);
+      return ERROR;
+    }
+
+  if ((mqdes->oflags & O_RDOK) == 0)
+    {
+      set_errno(EPERM);
+      return ERROR;
+    }
+
+  if (msglen < (size_t)mqdes->msgq->maxmsgsize)
+    {
+      set_errno(EMSGSIZE);
+      return ERROR;
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: mq_waitreceive
+ *
+ * Description:
+ *   This is internal, common logic shared by both mq_receive and
+ *   mq_timedreceive.  This function waits for a message to be received on
+ *   the specified message queue, removes the message from the queue, and
+ *   returns it.
+ *
+ * Parameters:
+ *   mqdes - Message queue descriptor
+ *
+ * Return Value:
+ *   On success, a reference to the received message.  If the wait was
+ *   interrupted by a signal or a timeout, then the errno will be set
+ *   appropriately and NULL will be returned.
+ *
+ * Assumptions:
+ * - The caller has provided all validity checking of the input parameters
+ *   using mq_verifyreceive.
+ * - Interrupts should be disabled throughout this call.  This is necessary
+ *   because messages can be sent from interrupt level processing.
+ * - For mq_timedreceive, setting of the timer and this wait must be atomic.
+ *
+ ****************************************************************************/
+
+FAR mqmsg_t *mq_waitreceive(mqd_t mqdes)
+{
+  FAR _TCB    *rtcb;
+  FAR msgq_t  *msgq;
+  FAR mqmsg_t *rcvmsg;
+
+  /* Get a pointer to the message queue */
+
+  msgq = mqdes->msgq;
+
+  /* Get the message from the head of the queue */
+
+  while ((rcvmsg = (FAR mqmsg_t*)sq_remfirst(&msgq->msglist)) == NULL)
+    {
+      /* The queue is empty!  Should we block until there the above condition
+       * has been satisfied?
+       */
+
+      if ((mqdes->oflags & O_NONBLOCK) == 0)
+        {
+          /* Yes.. Block and try again */
+
+          rtcb = (FAR _TCB*)g_readytorun.head;
+          rtcb->msgwaitq = msgq;
+          msgq->nwaitnotempty++;
+
+          set_errno(OK);
+          up_block_task(rtcb, TSTATE_WAIT_MQNOTEMPTY);
+
+          /* When we resume at this point, either (1) the message queue
+           * is no longer empty, or (2) the wait has been interrupted by
+           * a signal.  We can detect the latter case be examining the
+           * errno value (should be either EINTR or ETIMEDOUT).
+           */
+
+          if (get_errno() != OK)
+            {
+              break;
+            }
+        }
+      else
+        {
+          /* The queue was empty, and the O_NONBLOCK flag was set for the
+           * message queue description referred to by 'mqdes'.
+           */
+
+          set_errno(EAGAIN);
+          break;
+        }
+    }
+
+  /* If we got message, then decrement the number of messages in
+   * the queue while we are still in the critical section
+   */
+
+  if (rcvmsg)
+    {
+      msgq->nmsgs--;
+    }
+
+  return rcvmsg;
+}
+
+/****************************************************************************
+ * Name: mq_doreceive
+ *
+ * Description:
+ *   This is internal, common logic shared by both mq_receive and
+ *   mq_timedreceive.  This function accepts the message obtained by
+ *   mq_waitmsg, provides the message content to the user, notifies any
+ *   threads that were waiting for the message queue to become non-full,
+ *   and disposes of the message structure
+ *
+ * Parameters:
+ *   mqdes - Message queue descriptor
+ *   mqmsg   - The message obtained by mq_waitmsg()
+ *   ubuffer - The address of the user provided buffer to receive the message
+ *   prio    - The user-provided location to return the message priority.
+ *
+ * Return Value:
+ *   Returns the length of the received message.  This function does not fail.
+ *
+ * Assumptions:
+ * - The caller has provided all validity checking of the input parameters
+ *   using mq_verifyreceive.
+ * - The user buffer, ubuffer, is known to be large enough to accept the
+ *   largest message that an be sent on this message queue
+ * - Pre-emption should be disabled throughout this call.
+ *
+ ****************************************************************************/
+
+ssize_t mq_doreceive(mqd_t mqdes, mqmsg_t *mqmsg, void *ubuffer, int *prio)
+{
+  FAR _TCB   *btcb;
+  irqstate_t  saved_state;
+  FAR msgq_t *msgq;
+  ssize_t     rcvmsglen;
+
+  /* Get the length of the message (also the return value) */
+
+  rcvmsglen = mqmsg->msglen;
+
+  /* Copy the message into the caller's buffer */
+
+  memcpy(ubuffer, (const void*)mqmsg->mail, rcvmsglen);
+
+  /* Copy the message priority as well (if a buffer is provided) */
+
+  if (prio)
+    {
+      *prio = mqmsg->priority;
+    }
+
+  /* We are done with the message.  Deallocate it now. */
+
+  mq_msgfree(mqmsg);
+
+  /* Check if any tasks are waiting for the MQ not full event. */
+
+  msgq = mqdes->msgq;
+  if (msgq->nwaitnotfull > 0)
+    {
+      /* Find the highest priority task that is waiting for
+       * this queue to be not-full in g_waitingformqnotfull list.
+       * This must be performed in a critical section because
+       * messages can be sent from interrupt handlers.
+       */
+
+      saved_state = irqsave();
+      for (btcb = (FAR _TCB*)g_waitingformqnotfull.head;
+           btcb && btcb->msgwaitq != msgq;
+           btcb = btcb->flink);
+
+      /* If one was found, unblock it.  NOTE:  There is a race
+       * condition here:  the queue might be full again by the
+       * time the task is unblocked
+       */
+
+      if (!btcb)
+        {
+          PANIC(OSERR_MQNOTFULLCOUNT);
+        }
+      else
+        {
+          btcb->msgwaitq = NULL;
+          msgq->nwaitnotfull--;
+          up_unblock_task(btcb);
+        }
+
+      irqrestore(saved_state);
+    }
+
+  /* Return the length of the message transferred to the user buffer */
+
+  return rcvmsglen;
+}