Add support for freopen()

ChangeLog

@@ -11138,3 +11138,5 @@
 	* fs/vfs/open.c: If the use attempts to open a block driver, use
 	  block_proxy() to insert a character driver conversion layer in front
 	  of the block driver (2015-11-21).
+	* libc/stdio/lib_freopen.c and include/stdio.h:  Add support for
+	  freopen() (2015-11-22).

drivers/pipes/pipe_common.c

@@ -371,7 +371,7 @@ int pipecommon_close(FAR struct file *filep)
         }
     }
 
-  /* What is the buffer management policy?  Do we free the buffe when the
+  /* What is the buffer management policy?  Do we free the buffer when the
    * last client closes the pipe policy 0, or when the buffer becomes empty.
    * In the latter case, the buffer data will remain valid and can be
    * obtained when the pipe is re-opened.

fs/vfs/fs_open.c

@@ -51,6 +51,7 @@
 #include <nuttx/fs/fs.h>
 
 #include "inode/inode.h"
+#include "driver/driver.h"
 
 /****************************************************************************
  * Private Functions

include/fcntl.h

@@ -102,7 +102,7 @@
 #define F_GETSIG    6  /* Get the signal sent */
 #define F_NOTIFY    7  /* Provide notification when directory referred to by fd changes (linux)*/
 #define F_SETFD     8  /* Set the file descriptor flags to value */
-#define F_SETFL     9  /* Set  the  file status flags to the value */
+#define F_SETFL     9  /* Set the file status flags to the value */
 #define F_SETLEASE  10 /* Set or remove file lease (linux) */
 #define F_SETLK     11 /* Acquire or release a lock on range of bytes */
 #define F_SETLKW    12 /* Like F_SETLK, but wait for lock to become available */

include/stdio.h

@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/stdio.h
  *
- *   Copyright (C) 2007-2009, 2011, 2013-2014 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011, 2013-2015 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -147,6 +147,7 @@ int    fprintf(FAR FILE *stream, FAR const char *format, ...);
 int    fputc(int c, FAR FILE *stream);
 int    fputs(FAR const char *s, FAR FILE *stream);
 size_t fread(FAR void *ptr, size_t size, size_t n_items, FAR FILE *stream);
+FAR FILE *freopen(FAR const char *path, FAR const char *mode, FAR FILE *stream);
 int    fseek(FAR FILE *stream, long int offset, int whence);
 int    fsetpos(FAR FILE *stream, FAR fpos_t *pos);
 long   ftell(FAR FILE *stream);

libc/lib_internal.h

@@ -155,7 +155,11 @@ char *__dtoa(double d, int mode, int ndigits, int *decpt, int *sign,
              char **rve);
 #endif
 
-/* Defined in lib_libwrite.c */
+/* Defined in lib_fopen.c */
+
+int lib_mode2oflags(FAR const char *mode);
+
+/* Defined in lib_libfwrite.c */
 
 ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream);
 

libc/stdio/Make.defs

@@ -56,14 +56,15 @@ CSRCS += lib_rawsostream.c
 
 ifneq ($(CONFIG_NFILE_STREAMS),0)
 
-CSRCS += lib_fopen.c lib_fclose.c lib_fread.c lib_libfread.c lib_fseek.c
-CSRCS += lib_ftell.c lib_fsetpos.c lib_fgetpos.c lib_fgetc.c lib_fgets.c
-CSRCS += lib_gets_s.c lib_gets.c lib_libfgets.c lib_fwrite.c lib_libfwrite.c
-CSRCS += lib_fflush.c lib_libflushall.c lib_libfflush.c lib_rdflush.c
-CSRCS += lib_wrflush.c lib_fputc.c lib_puts.c lib_fputs.c lib_ungetc.c
-CSRCS += lib_vprintf.c lib_fprintf.c lib_vfprintf.c lib_stdinstream.c
-CSRCS += lib_stdoutstream.c lib_stdsistream.c lib_stdsostream.c lib_perror.c
-CSRCS += lib_feof.c lib_ferror.c lib_clearerr.c
+CSRCS += lib_fopen.c lib_freopen.c lib_fclose.c lib_fread.c lib_libfread.c
+CSRCS += lib_fseek.c lib_ftell.c lib_fsetpos.c lib_fgetpos.c lib_fgetc.c
+CSRCS += lib_fgets.c lib_gets_s.c lib_gets.c lib_libfgets.c lib_fwrite.c
+CSRCS += lib_libfwrite.c lib_fflush.c lib_libflushall.c lib_libfflush.c
+CSRCS += lib_rdflush.c lib_wrflush.c lib_fputc.c lib_puts.c lib_fputs.c
+CSRCS += lib_ungetc.c lib_vprintf.c lib_fprintf.c lib_vfprintf.c
+CSRCS += lib_stdinstream.c lib_stdoutstream.c lib_stdsistream.c
+CSRCS += lib_stdsostream.c lib_perror.c lib_feof.c lib_ferror.c
+CSRCS += lib_clearerr.c
 
 endif
 

libc/stdio/lib_fileno.c

@@ -53,6 +53,7 @@
 int fileno(FAR FILE *stream)
 {
   int ret = -1;
+
   if (stream)
     {
       ret = stream->fs_fd;

libc/stdio/lib_fopen.c

@@ -69,18 +69,76 @@
 #define MODE_MASK (MODE_R | MODE_W | MODE_A)
 
 /****************************************************************************
- * Private Types
+ * Public Functions
  ****************************************************************************/
 
 /****************************************************************************
- * Private Functions
+ * Name: fdopen
  ****************************************************************************/
 
+FAR FILE *fdopen(int fd, FAR const char *mode)
+{
+  FAR FILE *ret = NULL;
+  int oflags;
+
+  /* Map the open mode string to open flags */
+
+  oflags = lib_mode2oflags(mode);
+  if (oflags >= 0)
+    {
+      ret = fs_fdopen(fd, oflags, NULL);
+    }
+
+  return ret;
+}
+
+/****************************************************************************
+ * Name: fopen
+ ****************************************************************************/
+
+FAR FILE *fopen(FAR const char *path, FAR const char *mode)
+{
+  FAR FILE *ret = NULL;
+  int oflags;
+  int fd;
+
+  /* Map the open mode string to open flags */
+
+  oflags = lib_mode2oflags(mode);
+  if (oflags < 0)
+    {
+      return NULL;
+    }
+
+  /* Open the file */
+
+  fd = open(path, oflags, 0666);
+
+  /* If the open was successful, then fdopen() the fil using the file
+   * descriptor returned by open.  If open failed, then just return the
+   * NULL stream -- open() has already set the errno.
+   */
+
+  if (fd >= 0)
+    {
+      ret = fs_fdopen(fd, oflags, NULL);
+      if (!ret)
+        {
+          /* Don't forget to close the file descriptor if any other
+           * failures are reported by fdopen().
+           */
+
+          (void)close(fd);
+        }
+    }
+  return ret;
+}
+
 /****************************************************************************
  * Name: lib_mode2oflags
  ****************************************************************************/
 
-static int lib_mode2oflags(FAR const char *mode)
+int lib_mode2oflags(FAR const char *mode)
 {
   unsigned int state;
   int oflags;
@@ -246,69 +304,3 @@ errout:
   set_errno(EINVAL);
   return ERROR;
 }
-
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-/****************************************************************************
- * Name: fdopen
- ****************************************************************************/
-
-FAR FILE *fdopen(int fd, FAR const char *mode)
-{
-  FAR FILE *ret = NULL;
-  int oflags;
-
-  /* Map the open mode string to open flags */
-
-  oflags = lib_mode2oflags(mode);
-  if (oflags >= 0)
-    {
-      ret = fs_fdopen(fd, oflags, NULL);
-    }
-
-  return ret;
-}
-
-/****************************************************************************
- * Name: fopen
- ****************************************************************************/
-
-FAR FILE *fopen(FAR const char *path, FAR const char *mode)
-{
-  FAR FILE *ret = NULL;
-  int oflags;
-  int fd;
-
-  /* Map the open mode string to open flags */
-
-  oflags = lib_mode2oflags(mode);
-  if (oflags < 0)
-    {
-      return NULL;
-    }
-
-  /* Open the file */
-
-  fd = open(path, oflags, 0666);
-
-  /* If the open was successful, then fdopen() the fil using the file
-   * descriptor returned by open.  If open failed, then just return the
-   * NULL stream -- open() has already set the errno.
-   */
-
-  if (fd >= 0)
-    {
-      ret = fs_fdopen(fd, oflags, NULL);
-      if (!ret)
-        {
-          /* Don't forget to close the file descriptor if any other
-           * failures are reported by fdopen().
-           */
-
-          (void)close(fd);
-        }
-    }
-  return ret;
-}

libc/stdio/lib_freopen.c

@@ -0,0 +1,143 @@
+/****************************************************************************
+ * libc/stdio/lib_freopen.c
+ *
+ *   Copyright (C) 2015 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 <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "lib_internal.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: freopen
+ *
+ * Description:
+ *   Reuses stream to either open the file specified by path or to change
+ *   its access mode.
+ *
+ *   If a new path is specified, the function first attempts to close
+ *   any file already associated with stream (third parameter) and
+ *   disassociates it. Then, independently of whether that stream was
+ *   successfuly closed or not, freopen opens the file specified by path
+ *   and associates it with the stream just as fopen would do using the
+ *   specified mode.
+ *
+ *   If path is a null pointer, the function attempts to change the mode
+ *   of the stream. Although a particular library implementation is allowed
+ *   to restrict the changes permitted, and under which circumstances.
+ *
+ *   The error indicator and eof indicator are automatically cleared (as if
+ *   clearerr was called).
+ *
+ * Input Paramters:
+ *   path   - If non-NULL, refers to the name of the file to be opened.
+ *   mode   - String describing the new file access mode
+ *   stream - Pointer to the type FILE to be reopened.
+ *
+ * Returned Value:
+ *   If the file is successfully reopened, the function returns the pointer
+ *   passed as parameter stream, which can be used to identify the reopened
+ *   stream.   Otherwise, a null pointer is returned and the errno variable
+ *   is also set to a system-specific error code on failure.
+ *
+ ****************************************************************************/
+
+FAR FILE *freopen(FAR const char *path, FAR const char *mode,
+                  FAR FILE *stream)
+{
+  int oflags;
+  int ret;
+  int fd;
+
+  /* Was a file name provided? */
+
+  if (path != NULL)
+    {
+      /* Yes, close the stream */
+
+      if (stream)
+        {
+          (void)fclose(stream);
+        }
+
+      /* And attempt to reopen the file at the provided path */
+
+      return fopen(path, mode);
+    }
+
+  /* Otherwise, we are just changing the mode of the current file. */
+
+  if (stream)
+    {
+      /* Convert the mode string into standard file open mode flags. */
+
+      oflags = lib_mode2oflags(mode);
+      if (oflags == 0)
+        {
+          return NULL;
+        }
+
+      /* Get the underlying file descriptor from the stream */
+
+      fd = fileno(stream);
+      if (fd < 0)
+        {
+          return NULL;
+        }
+
+      /* Set the new file mode for the file descriptor */
+
+      ret = fcntl(fd, F_SETFL, oflags);
+      if (ret < 0)
+        {
+          return NULL;
+        }
+
+      clearerr(stream);
+      return stream;
+    }
+
+  set_errno(EINVAL);
+  return NULL;
+}