Trying to recover from deleted directory contents

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5329 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 315 insertions, 0 deletions

diff --git a/nuttx/lib/stdio/lib_libfread.c b/nuttx/lib/stdio/lib_libfread.c
new file mode 100644
index 000000000..5585acbae
--- /dev/null
+++ b/nuttx/lib/stdio/lib_libfread.c
@@ -0,0 +1,315 @@
+/****************************************************************************
+ * lib/stdio/lib_libfread.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>  /* for CONFIG_STDIO_BUFFER_SIZE */
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "lib_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Constant Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Constant Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lib_fread
+ ****************************************************************************/
+
+ssize_t lib_fread(FAR void *ptr, size_t count, FAR FILE *stream)
+{
+  unsigned char *dest  = (unsigned char*)ptr;
+  ssize_t        bytes_read;
+  int            ret;
+
+  /* Make sure that reading from this stream is allowed */
+
+  if (!stream || (stream->fs_oflags & O_RDOK) == 0)
+    {
+      set_errno(EBADF);
+      bytes_read = -1;
+    }
+  else
+    {
+      /* The stream must be stable until we complete the read */
+
+      lib_take_semaphore(stream);
+
+#if CONFIG_NUNGET_CHARS > 0
+      /* First, re-read any previously ungotten characters */
+
+      while ((stream->fs_nungotten > 0) && (count > 0))
+        {
+          /* Decrement the count of ungotten bytes to get an index */
+
+          stream->fs_nungotten--;
+
+          /* Return the last ungotten byte */
+
+          *dest++ = stream->fs_ungotten[stream->fs_nungotten];
+
+          /* That's one less byte that we have to read */
+
+          count--;
+        }
+#endif
+
+#if CONFIG_STDIO_BUFFER_SIZE > 0
+      /* If the buffer is currently being used for write access, then
+       * flush all of the buffered write data.  We do not support concurrent
+       * buffered read/write access.
+       */
+
+      ret = lib_wrflush(stream);
+      if (ret < 0)
+        {
+          lib_give_semaphore(stream);
+          return ret;
+        }
+
+      /* Now get any other needed chars from the buffer or the file. */
+
+      while (count > 0)
+        {
+          /* Is there readable data in the buffer? */
+
+          while ((count > 0) && (stream->fs_bufpos < stream->fs_bufread))
+            {
+              /* Yes, copy a byte into the user buffer */
+
+              *dest++ = *stream->fs_bufpos++;
+              count--;
+            }
+
+          /* The buffer is empty OR we have already supplied the number of
+           * bytes requested in the read.  Check if we need to read
+           * more from the file.
+           */
+
+          if (count > 0)
+            {
+              size_t buffer_available;
+
+              /* We need to read more data into the buffer from the file */
+
+              /* Mark the buffer empty */
+
+              stream->fs_bufpos = stream->fs_bufread = stream->fs_bufstart;
+
+              /* How much space is available in the buffer? */
+
+              buffer_available = stream->fs_bufend - stream->fs_bufread;
+
+              /* Will the number of bytes that we need to read fit into
+               * the buffer space that is available? If the read size is
+               * larger than the buffer, then read some of the data
+               * directly into the user's buffer.
+               */
+
+              if (count > buffer_available)
+                {
+                  bytes_read = read(stream->fs_filedes, dest, count);
+                  if (bytes_read < 0)
+                    {
+                      /* An error occurred on the read.  The error code is
+                       * in the 'errno' variable.
+                       */
+
+                      goto errout_with_errno;
+                    }
+                  else if (bytes_read == 0)
+                    {
+                      /* We are at the end of the file.  But we may already
+                       * have buffered data.  In that case, we will report
+                       * the EOF indication later.
+                       */
+
+                      goto shortread;
+                    }
+                  else
+                    {
+                      /* Some bytes were read. Adjust the dest pointer */
+
+                      dest  += bytes_read;
+
+                      /* Were all of the requested bytes read? */
+
+                      if (bytes_read < count)
+                        {
+                          /* No.  We must be at the end of file. */
+
+                          goto shortread;
+                        }
+                      else
+                        {
+                          /* Yes.  We are done. */
+
+                          count = 0;
+                        }
+                    }
+                }
+              else
+                {
+                  /* The number of bytes required to satisfy the read
+                   * is less than or equal to the size of the buffer
+                   * space that we have left. Read as much as we can
+                   * into the buffer.
+                   */
+
+                  bytes_read = read(stream->fs_filedes, stream->fs_bufread, buffer_available);
+                  if (bytes_read < 0)
+                    {
+                      /* An error occurred on the read.  The error code is
+                       * in the 'errno' variable.
+                       */
+
+                      goto errout_with_errno;
+                    }
+                  else if (bytes_read == 0)
+                    {
+                      /* We are at the end of the file.  But we may already
+                       * have buffered data.  In that case, we will report
+                       * the EOF indication later.
+                       */
+
+                      goto shortread;
+                    }
+                  else
+                    {
+                      /* Some bytes were read */
+
+                      stream->fs_bufread += bytes_read;
+                    }
+                }
+            }
+        }
+#else
+      /* Now get any other needed chars from the file. */
+
+      while (count > 0)
+        {
+          bytes_read = read(stream->fs_filedes, dest, count);
+          if (bytes_read < 0)
+            {
+              /* An error occurred on the read.  The error code is
+               * in the 'errno' variable.
+               */
+
+              goto errout_with_errno;
+            }
+          else if (bytes_read == 0)
+            {
+              /* We are at the end of the file.  But we may already
+               * have buffered data.  In that case, we will report
+               * the EOF indication later.
+               */
+
+              break;
+            }
+          else
+            {
+              dest  += bytes_read;
+              count -= bytes_read;
+            }
+        }
+#endif
+      /* Here after a successful (but perhaps short) read */
+
+#if CONFIG_STDIO_BUFFER_SIZE > 0
+    shortread:
+#endif
+      bytes_read = dest - (unsigned char*)ptr;
+
+      /* Set or clear the EOF indicator.  If we get here because of a
+       * short read and the total number of* bytes read is zero, then
+       * we must be at the end-of-file.
+       */
+
+      if (bytes_read > 0)
+        {
+          stream->fs_flags &= ~__FS_FLAG_EOF;
+        }
+      else
+        {
+          stream->fs_flags |= __FS_FLAG_EOF;
+        }
+    }
+
+  lib_give_semaphore(stream);
+  return bytes_read;  
+
+/* Error exits */
+
+errout_with_errno:
+  lib_give_semaphore(stream);
+  return -get_errno();  
+}
+