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diff --git a/nuttx/lib/stdio/lib_fopen.c b/nuttx/lib/stdio/lib_fopen.c
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+/****************************************************************************
+ * lib/stdio/lib_fopen.c
+ *
+ * Copyright (C) 2007-2012 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 <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+
+#include "lib_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+enum open_mode_e
+{
+ MODE_NONE = 0, /* No access mode determined */
+ MODE_R, /* "r" or "rb" open for reading */
+ MODE_W, /* "w" or "wb" open for writing, truncating or creating file */
+ MODE_A, /* "a" or "ab" open for writing, appending to file */
+ MODE_RPLUS, /* "r+", "rb+", or "r+b" open for update (reading and writing) */
+ MODE_WPLUS, /* "w+", "wb+", or "w+b" open for update, truncating or creating file */
+ MODE_APLUS /* "a+", "ab+", or "a+b" open for update, appending to file */
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lib_mode2oflags
+ ****************************************************************************/
+
+static int lib_mode2oflags(FAR const char *mode)
+{
+ enum open_mode_e state;
+ int oflags;
+
+ /* Verify that a mode string was provided. No error is */
+
+ if (!mode)
+ {
+ goto errout;
+ }
+
+ /* Parse the mode string to determine the corresponding open flags */
+
+ state = MODE_NONE;
+ oflags = 0;
+
+ for (; *mode; mode++)
+ {
+ switch (*mode)
+ {
+ /* Open for read access ("r", "r[+]", "r[b]", "r[b+]", or "r[+b]") */
+
+ case 'r' :
+ if (state == MODE_NONE)
+ {
+ /* Open for read access */
+
+ oflags = O_RDOK;
+ state = MODE_R;
+ }
+ else
+ {
+ goto errout;
+ }
+ break;
+
+ /* Open for write access ("w", "w[+]", "w[b]", "w[b+]", or "w[+b]") */
+
+ case 'w' :
+ if (state == MODE_NONE)
+ {
+ /* Open for write access, truncating any existing file */
+
+ oflags = O_WROK|O_CREAT|O_TRUNC;
+ state = MODE_W;
+ }
+ else
+ {
+ goto errout;
+ }
+ break;
+
+ /* Open for write/append access ("a", "a[+]", "a[b]", "a[b+]", or "a[+b]") */
+
+ case 'a' :
+ if (state == MODE_NONE)
+ {
+ /* Write to the end of the file */
+
+ oflags = O_WROK|O_CREAT|O_APPEND;
+ state = MODE_A;
+ }
+ else
+ {
+ goto errout;
+ }
+ break;
+
+ /* Open for update access ("[r]+", "[rb]+]", "[r]+[b]", "[w]+",
+ * "[wb]+]", "[w]+[b]", "[a]+", "[ab]+]", "[a]+[b]")
+ */
+
+ case '+' :
+ switch (state)
+ {
+ case MODE_R:
+ {
+ /* Retain any binary mode selection */
+
+ oflags &= O_BINARY;
+
+ /* Open for read/write access */
+
+ oflags |= O_RDWR;
+ state = MODE_RPLUS;
+ }
+ break;
+
+ case MODE_W:
+ {
+ /* Retain any binary mode selection */
+
+ oflags &= O_BINARY;
+
+ /* Open for write read/access, truncating any existing file */
+
+ oflags |= O_RDWR|O_CREAT|O_TRUNC;
+ state = MODE_WPLUS;
+ }
+ break;
+
+ case MODE_A:
+ {
+ /* Retain any binary mode selection */
+
+ oflags &= O_BINARY;
+
+ /* Read from the beginning of the file; write to the end */
+
+ oflags |= O_RDWR|O_CREAT|O_APPEND;
+ state = MODE_APLUS;
+ }
+ break;
+
+ default:
+ goto errout;
+ break;
+ }
+ break;
+
+ /* Open for binary access ("[r]b", "[r]b[+]", "[r+]b", "[w]b",
+ * "[w]b[+]", "[w+]b", "[a]b", "[a]b[+]", "[a+]b")
+ */
+
+ case 'b' :
+ if (state != MODE_NONE)
+ {
+ /* The file is opened in binary mode */
+
+ oflags |= O_BINARY;
+ }
+ else
+ {
+ goto errout;
+ }
+ break;
+
+ /* Unrecognized or unsupported mode */
+
+ default:
+ goto errout;
+ break;
+ }
+ }
+
+ return oflags;
+
+/* Both fopen and fdopen should fail with errno == EINVAL if the mode
+ * string is invalid.
+ */
+
+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
+ * desciptor 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;
+}
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