NuttX RTOS

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 273 insertions, 0 deletions

diff --git a/nuttx/fs/fs_files.c b/nuttx/fs/fs_files.c
new file mode 100644
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+/************************************************************
+ * fs_files.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 <nuttx/config.h>
+
+
+#if CONFIG_NFILE_DESCRIPTORS >0
+
+#include <string.h>
+#include <semaphore.h>
+#include <assert.h>
+#include <sched.h>
+#include <errno.h>
+#include <nuttx/fs.h>
+#include <nuttx/kmalloc.h>
+
+#include "fs_internal.h"
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Public Types
+ ************************************************************/
+
+/************************************************************
+ * Private Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Variables
+ ************************************************************/
+
+/************************************************************
+ * Private Functions
+ ************************************************************/
+
+static void _files_semtake(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_ptr() == EINTR);
+    }
+}
+
+static inline void _files_semgive(struct filelist *list)
+{
+  sem_post(&list->fl_sem);
+}
+
+/************************************************************
+ * Pulblic Functions
+ ************************************************************/
+
+/* This is called from the FS initialization logic to configure
+ * the files.
+ */
+
+void files_initialize(void)
+{
+}
+
+/* Allocate a list of files for a new task */
+
+struct filelist *files_alloclist(void)
+{
+  struct filelist *list;
+  list = (struct filelist*)kzmalloc(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;
+}
+
+/* Increase the reference count on a file list */
+
+int files_addreflist(struct filelist *list)
+{
+  if (list)
+    {
+       /* Increment the reference count on the list */
+
+       _files_semtake(list);
+       list->fl_crefs++;
+       _files_semgive(list);
+    }
+  return OK;
+}
+
+/* Release a reference to the file list */
+
+int files_releaselist(struct filelist *list)
+{
+  int crefs;
+  if (list)
+    {
+       /* Decrement the reference count */
+
+       _files_semtake(list);
+       crefs = --list->fl_crefs;
+       _files_semgive(list);
+
+       /* If the count decrements to zero, then there is no reference
+        * to the structure and it should be deallocated.
+        */
+
+       if (crefs <= 0)
+          {
+            int i;
+
+            /* close each file descriptor */
+
+            for (i = 0; i < CONFIG_NFILE_DESCRIPTORS; i++)
+              {
+                struct inode *inode = list->fl_files[i].f_inode;
+                if (inode)
+                  {
+                    inode_release(inode);
+                  }
+              }
+
+             /* Destroy the semaphore and release the filelist */
+
+             (void)sem_destroy(&list->fl_sem);
+             sched_free(list);
+          }
+    }
+  return OK;
+}
+
+/* Assign an inode to a specific files structure.  this is the
+ * heart of dup2.
+ */
+
+int files_dup(struct file *filep1, struct file *filep2)
+{
+  struct filelist *list;
+
+  if (!filep1 || !filep1->f_inode || !filep2)
+    {
+      *get_errno_ptr() = EBADF;
+      return ERROR;
+    }
+
+  list = sched_getfiles();
+  if (!list)
+    {
+      *get_errno_ptr() = EMFILE;
+      return ERROR;
+    }
+
+  _files_semtake(list);
+
+  /* If there is already an inode contained in the new file structure,
+   * release it (effectively closing the file).
+   */
+
+  if (filep2->f_inode)
+    {
+      inode_release(filep2->f_inode);
+    }
+
+  /* Increment the reference count on the contained inode */
+
+  inode_addref(filep1->f_inode);
+
+  /* Then clone the file structure */
+
+  filep2->f_oflags = filep1->f_oflags;
+  filep2->f_pos    = filep1->f_pos;
+  filep2->f_inode  = filep1->f_inode;
+  _files_semgive(list);
+  return OK;
+}
+
+/* Allocate a struct files instance and associate it with an
+ * inode instance.  Returns the file descriptor == index into
+ * the files array.
+ */
+
+int files_allocate(struct inode *inode, int oflags, off_t pos)
+{
+  struct filelist *list;
+  int i;
+
+  list = sched_getfiles();
+  if (list)
+    {
+    _files_semtake(list);
+    for (i = 0; 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;
+}
+
+void files_release(int filedes)
+{
+  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);
+        }
+    }
+}
+#endif /* CONFIG_NFILE_DESCRIPTORS */