1 files changed, 147 insertions, 0 deletions
diff --git a/nuttx/fs/fs_read.c b/nuttx/fs/fs_read.c
new file mode 100644
index 000000000..30dd4af03
--- /dev/null
+++ b/nuttx/fs/fs_read.c
@@ -0,0 +1,147 @@
+/****************************************************************************
+ * fs_read.c
+ *
+ *   Copyright (C) 2007-2009, 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 <sys/socket.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <errno.h>
+
+#include "fs_internal.h"
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+static inline ssize_t file_read(int fd, FAR void *buf, size_t nbytes)
+{
+  FAR struct filelist *list;
+  int ret = -EBADF;
+
+  /* Get the thread-specific file list */
+
+  list = sched_getfiles();
+  if (!list)
+    {
+      /* Failed to get the file list */
+
+      ret = -EMFILE;
+    }
+
+  /* Were we given a valid file descriptor? */
+
+  else if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS)
+    {
+      FAR struct file *this_file = &list->fl_files[fd];
+      FAR struct inode *inode    = this_file->f_inode;
+
+      /* Yes.. Was this file opened for read access? */
+
+      if ((this_file->f_oflags & O_RDOK) == 0)
+        {
+          /* No.. File is not read-able */
+
+          ret = -EACCES;
+        }
+
+      /* Is a driver or mountpoint registered? If so, does it support
+       * the read method?
+       */
+
+      else if (inode && inode->u.i_ops && inode->u.i_ops->read)
+        {
+          /* Yes.. then let it perform the read.  NOTE that for the case
+           * of the mountpoint, we depend on the read methods bing
+           * identical in signature and position in the operations vtable.
+           */
+
+          ret = (int)inode->u.i_ops->read(this_file, (char*)buf, (size_t)nbytes);
+        }
+    }
+
+  /* If an error occurred, set errno and return -1 (ERROR) */
+
+  if (ret < 0)
+    {
+      set_errno(-ret);
+      return ERROR;
+    }
+
+  /* Otherwise, return the number of bytes read */
+
+  return ret;
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+ssize_t read(int fd, FAR void *buf, size_t nbytes)
+{
+  /* Did we get a valid file descriptor? */
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+  if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
+#endif
+    {
+      /* No.. If networking is enabled, read() is the same as recv() with
+       * the flags parameter set to zero.
+       */
+
+#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
+      return recv(fd, buf, nbytes, 0);
+#else
+      /* No networking... it is a bad descriptor in any event */
+
+      set_errno(EBADF);
+      return ERROR;
+#endif
+    }
+
+  /* The descriptor is in a valid range to file descriptor... do the read */
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+  return file_read(fd, buf, nbytes);
+#endif
+}