1 files changed, 479 insertions, 0 deletions
diff --git a/nuttx/fs/fs_files.c b/nuttx/fs/fs_files.c
new file mode 100644
index 000000000..033cd8c63
--- /dev/null
+++ b/nuttx/fs/fs_files.c
@@ -0,0 +1,479 @@
+/****************************************************************************
+ * fs/fs_files.c
+ *
+ *   Copyright (C) 2007-2009, 2011-2012 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 <string.h>
+#include <semaphore.h>
+#include <assert.h>
+#include <sched.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+#include <nuttx/kmalloc.h>
+
+#include "fs_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: _files_semtake
+ ****************************************************************************/
+
+static void _files_semtake(FAR struct filelist *list)
+{
+  /* Take the semaphore (perhaps waiting) */
+
+  while (sem_wait(&list->fl_sem) != 0)
+    {
+      /* The only case that an error should occr here is if
+       * the wait was awakened by a signal.
+       */
+
+      ASSERT(get_errno() == EINTR);
+    }
+}
+
+/****************************************************************************
+ * Name: _files_semgive
+ ****************************************************************************/
+
+#define _files_semgive(list) sem_post(&list->fl_sem)
+
+/****************************************************************************
+ * Name: _files_close
+ *
+ * Description:
+ *   Close an inode (if open)
+ *
+ * Assumuptions:
+ *   Caller holds the list semaphore because the file descriptor will be freed.
+ *
+ ****************************************************************************/
+
+static int _files_close(FAR struct file *filep)
+{
+  struct inode *inode = filep->f_inode;
+  int ret = OK;
+
+  /* Check if the struct file is open (i.e., assigned an inode) */
+
+  if (inode)
+    {
+      /* Close the file, driver, or mountpoint. */
+
+      if (inode->u.i_ops && inode->u.i_ops->close)
+        {
+          /* Perform the close operation */
+
+          ret = inode->u.i_ops->close(filep);
+        }
+
+      /* And release the inode */
+
+      inode_release(inode);
+
+      /* Release the file descriptor */
+
+      filep->f_oflags  = 0;
+      filep->f_pos     = 0;
+      filep->f_inode = NULL;
+    }
+
+  return ret;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: files_initialize
+ *
+ * Description:
+ *   This is called from the FS initialization logic to configure the files.
+ *
+ ****************************************************************************/
+
+void files_initialize(void)
+{
+}
+
+/****************************************************************************
+ * Name: files_alloclist
+ *
+ * Description: Allocate a list of files for a new task
+ *
+ ****************************************************************************/
+
+FAR struct filelist *files_alloclist(void)
+{
+  FAR struct filelist *list;
+  list = (FAR struct filelist*)kzalloc(sizeof(struct filelist));
+  if (list)
+    {
+       /* Start with a reference count of one */
+
+       list->fl_crefs = 1;
+
+       /* Initialize the list access mutex */
+
+      (void)sem_init(&list->fl_sem, 0, 1);
+    }
+
+  return list;
+}
+
+/****************************************************************************
+ * Name: files_addreflist
+ *
+ * Description:
+ *   Increase the reference count on a file list
+ *
+ ****************************************************************************/
+
+int files_addreflist(FAR struct filelist *list)
+{
+  if (list)
+    {
+      /* Increment the reference count on the list.
+       * NOTE: that we disable interrupts to do this
+       * (vs. taking the list semaphore).  We do this
+       * because file cleanup operations often must be
+       * done from the IDLE task which cannot wait
+       * on semaphores.
+       */
+
+      register irqstate_t flags = irqsave();
+      list->fl_crefs++;
+      irqrestore(flags);
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: files_releaselist
+ *
+ * Description:
+ *   Release a reference to the file list
+ *
+ ****************************************************************************/
+
+int files_releaselist(FAR struct filelist *list)
+{
+  int crefs;
+  if (list)
+    {
+      /* Decrement the reference count on the list.
+       * NOTE: that we disable interrupts to do this
+       * (vs. taking the list semaphore).  We do this
+       * because file cleanup operations often must be
+       * done from the IDLE task which cannot wait
+       * on semaphores.
+       */
+
+      register irqstate_t flags = irqsave();
+      crefs = --(list->fl_crefs);
+      irqrestore(flags);
+
+      /* If the count decrements to zero, then there is no reference
+       * to the structure and it should be deallocated.  Since there
+       * are references, it would be an error if any task still held
+       * a reference to the list's semaphore.
+       */
+
+      if (crefs <= 0)
+        {
+          int i;
+
+          /* Close each file descriptor .. Normally, you would need
+           * take the list semaphore, but it is safe to ignore the
+           * semaphore in this context because there are no references
+           */
+
+          for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
+            {
+              (void)_files_close(&list->fl_files[i]);
+            }
+
+          /* Destroy the semaphore and release the filelist */
+
+          (void)sem_destroy(&list->fl_sem);
+          sched_free(list);
+        }
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: files_dup
+ *
+ * Description:
+ *   Assign an inode to a specific files structure.  This is the heart of
+ *   dup2.
+ *
+ ****************************************************************************/
+
+int files_dup(FAR struct file *filep1, FAR struct file *filep2)
+{
+  FAR struct filelist *list;
+  FAR struct inode *inode;
+  int err;
+  int ret;
+
+  if (!filep1 || !filep1->f_inode || !filep2)
+    {
+      err = EBADF;
+      goto errout;
+    }
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+  if (INODE_IS_MOUNTPT(filep1->f_inode))
+    {
+      err = ENOSYS; /* Not yet supported */
+      goto errout;
+    }
+#endif
+
+  list = sched_getfiles();
+  if (!list)
+    {
+      err = EMFILE;
+      goto errout;
+    }
+
+  _files_semtake(list);
+
+  /* If there is already an inode contained in the new file structure,
+   * close the file and release the inode.
+   */
+
+  ret = _files_close(filep2);
+  if (ret < 0)
+    {
+      /* An error occurred while closing the driver */
+
+      goto errout_with_ret;
+    }
+
+  /* Increment the reference count on the contained inode */
+
+  inode = filep1->f_inode;
+  inode_addref(inode);
+
+  /* Then clone the file structure */
+
+  filep2->f_oflags = filep1->f_oflags;
+  filep2->f_pos    = filep1->f_pos;
+  filep2->f_inode  = inode;
+
+  /* Call the open method on the file, driver, mountpoint so that it
+   * can maintain the correct open counts.
+   */
+
+  if (inode->u.i_ops && inode->u.i_ops->open)
+    {
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+#if 0 /* Not implemented */
+      if (INODE_IS_MOUNTPT(inode))
+        {
+         /* Open a file on the mountpoint */
+
+          ret = inode->u.i_mops->open(filep2, ?, filep2->f_oflags, ?);
+        }
+      else
+#endif
+#endif
+        {
+          /* Open the psuedo file or device driver */
+
+          ret = inode->u.i_ops->open(filep2);
+        }
+
+      /* Handle open failures */
+
+      if (ret < 0)
+        {
+          goto errout_with_inode;
+        }
+    }
+
+  _files_semgive(list);
+  return OK;
+
+/* Handler various error conditions */
+
+errout_with_inode:
+  inode_release(filep2->f_inode);
+  filep2->f_oflags = 0;
+  filep2->f_pos    = 0;
+  filep2->f_inode  = NULL;
+
+errout_with_ret:
+  err              = -ret;
+  _files_semgive(list);
+
+errout:
+  set_errno(err);
+  return ERROR;
+}
+
+/****************************************************************************
+ * Name: files_allocate
+ *
+ * Description:
+ *   Allocate a struct files instance and associate it with an inode instance. 
+ *   Returns the file descriptor == index into the files array.
+ *
+ ****************************************************************************/
+
+int files_allocate(FAR struct inode *inode, int oflags, off_t pos, int minfd)
+{
+  FAR struct filelist *list;
+  int i;
+
+  list = sched_getfiles();
+  if (list)
+    {
+      _files_semtake(list);
+      for (i = minfd; i < CONFIG_NFILE_DESCRIPTORS; i++)
+        {
+          if (!list->fl_files[i].f_inode)
+            {
+               list->fl_files[i].f_oflags = oflags;
+               list->fl_files[i].f_pos    = pos;
+               list->fl_files[i].f_inode  = inode;
+               _files_semgive(list);
+               return i;
+            }
+        }
+
+      _files_semgive(list);
+    }
+
+  return ERROR;
+}
+
+/****************************************************************************
+ * Name: files_close
+ *
+ * Description:
+ *   Close an inode (if open)
+ *
+ * Assumuptions:
+ *   Caller holds the list semaphore because the file descriptor will be freed.
+ *
+ ****************************************************************************/
+
+int files_close(int filedes)
+{
+  FAR struct filelist *list;
+  int                  ret;
+
+  /* Get the thread-specific file list */
+
+  list = sched_getfiles();
+  if (!list)
+    {
+      return -EMFILE;
+    }
+
+  /* If the file was properly opened, there should be an inode assigned */
+
+  if (filedes < 0 || filedes >= CONFIG_NFILE_DESCRIPTORS || !list->fl_files[filedes].f_inode)
+   {
+     return -EBADF;
+   }
+
+  /* Perform the protected close operation */
+
+  _files_semtake(list);
+  ret = _files_close(&list->fl_files[filedes]);
+  _files_semgive(list);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: files_release
+ *
+ * Assumuptions:
+ *   Similar to files_close().  Called only from open() logic on error
+ *   conditions.
+ *
+ ****************************************************************************/
+
+void files_release(int filedes)
+{
+  FAR struct filelist *list;
+
+  list = sched_getfiles();
+  if (list)
+    {
+      if (filedes >=0 && filedes < CONFIG_NFILE_DESCRIPTORS)
+        {
+          _files_semtake(list);
+          list->fl_files[filedes].f_oflags  = 0;
+          list->fl_files[filedes].f_pos     = 0;
+          list->fl_files[filedes].f_inode = NULL;
+          _files_semgive(list);
+        }
+    }
+}
+