pipes: support FIONREAD and FIONWRITE ioctl on pipes; use semaphores for pipecommon_ioctl().

arch @ 2a3c9628

-Subproject commit 2c6b85793f26fb265e88ff2fc3d4e71707f9ab2b
+Subproject commit 2a3c96286af41c261411d9cdd17e98e2ee18dc2e

drivers/pipes/fifo.c

@@ -50,18 +50,6 @@
 
 #if CONFIG_DEV_PIPE_SIZE > 0
 
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
-/****************************************************************************
- * Private Types
- ****************************************************************************/
-
-/****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
-
 /****************************************************************************
  * Private Data
  ****************************************************************************/
@@ -82,10 +70,6 @@ static const struct file_operations fifo_fops =
 #endif
 };
 
-/****************************************************************************
- * Private Functions
- ****************************************************************************/
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/

drivers/pipes/pipe_common.c

@@ -55,6 +55,7 @@
 
 #include <nuttx/kmalloc.h>
 #include <nuttx/fs/fs.h>
+#include <nuttx/fs/ioctl.h>
 #ifdef CONFIG_DEBUG
 #  include <nuttx/arch.h>
 #endif
@@ -77,20 +78,12 @@
 #  define pipe_dumpbuffer(m,a,n)
 #endif
 
-/****************************************************************************
- * Private Types
- ****************************************************************************/
-
 /****************************************************************************
  * Private Function Prototypes
  ****************************************************************************/
 
 static void pipecommon_semtake(sem_t *sem);
 
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -746,32 +739,90 @@ errout:
 }
 #endif
 
-/****************************************************************************
+/************************************************************************************
  * Name: pipecommon_ioctl
- ****************************************************************************/
+ ************************************************************************************/
 
-int  pipecommon_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
+int pipecommon_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
 {
-  FAR struct inode      *inode    = filep->f_inode;
-  FAR struct pipe_dev_s *dev      = inode->i_private;
+  FAR struct inode *inode = filep->f_inode;
+  struct pipe_dev_s *dev   = inode->i_private;
+  int ret = -EINVAL;
 
-  /* Only one command supported */
+#ifdef CONFIG_DEBUG
+  /* Some sanity checking */
 
-  if (cmd == PIPEIOC_POLICY)
+  if (dev == NULL)
     {
-      if (arg != 0)
+       return -EBADF;
+    }
+#endif
+
+  pipecommon_semtake(&dev->d_bfsem);
+
+  switch (cmd)
+    {
+      case PIPEIOC_POLICY:
         {
-          PIPE_POLICY_1(dev->d_flags);
+          if (arg != 0)
+            {
+              PIPE_POLICY_1(dev->d_flags);
+            }
+          else
+            {
+              PIPE_POLICY_0(dev->d_flags);
+            }
+
+          ret = OK;
         }
-      else
+        break;
+
+      case FIONREAD:
+        {
+          int count;
+
+          /* Determine the number of bytes available in the buffer */
+
+          if (dev->d_wrndx < dev->d_rdndx)
+            {
+              count = (CONFIG_DEV_PIPE_SIZE - dev->d_rdndx) + dev->d_wrndx;
+            }
+          else
+            {
+              count = dev->d_wrndx - dev->d_rdndx;
+            }
+
+          *(int *)arg = count;
+          ret = 0;
+        }
+        break;
+
+      case FIONWRITE:
         {
-          PIPE_POLICY_0(dev->d_flags);
+          int count;
+
+          /* Determine the number of bytes free in the buffer */
+
+          if (dev->d_wrndx < dev->d_rdndx)
+            {
+              count = (dev->d_rdndx - dev->d_wrndx) - 1;
+            }
+          else
+            {
+              count = ((CONFIG_DEV_PIPE_SIZE - dev->d_wrndx) + dev->d_rdndx) - 1;
+            }
+
+          *(int *)arg = count;
+          ret = 0;
         }
+        break;
 
-      return OK;
+      default:
+        break;
     }
 
-  return -ENOTTY;
+  sem_post(&dev->d_bfsem);
+  return ret;
 }
 
 /****************************************************************************

drivers/pipes/pipe_common.h

 /****************************************************************************
  * drivers/pipe/pipe_common.h
  *
- *   Copyright (C) 2008-2009, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2008-2009, 2015=2016 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without