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+/****************************************************************************
+ * lib/stdio/lib_fopen.c
+ *
+ * Copyright (C) 2007-2011 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 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"
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lib_mode2oflags
+ ****************************************************************************/
+
+static int lib_mode2oflags(FAR const char *mode)
+{
+ int oflags = 0;
+ if (mode)
+ {
+ while(*mode)
+ {
+ switch (*mode)
+ {
+ /* Open for read access */
+
+ case 'r' :
+ if (*(mode + 1) == '+')
+ {
+ /* Open for read/write access */
+ oflags |= O_RDWR;
+ mode++;
+ }
+ else
+ {
+ /* Open for read access */
+ oflags |= O_RDOK;
+ }
+ break;
+
+ /* Open for write access? */
+
+ case 'w' :
+ if (*(mode + 1) == '+')
+ {
+ /* Open for write read/access, truncating any existing file */
+ oflags |= O_RDWR|O_CREAT|O_TRUNC;
+ mode++;
+ }
+ else
+ {
+ /* Open for write access, truncating any existing file */
+ oflags |= O_WROK|O_CREAT|O_TRUNC;
+ }
+ break;
+
+ /* Open for write/append access? */
+
+ case 'a' :
+ if (*(mode + 1) == '+')
+ {
+ /* Read from the beginning of the file; write to the end */
+ oflags |= O_RDWR|O_CREAT;
+ mode++;
+ }
+ else
+ {
+ /* Write to the end of the file */
+ oflags |= O_WROK|O_CREAT;
+ }
+ break;
+
+ /* Open for binary access? */
+
+ case 'b' :
+ default:
+ break;
+ }
+ mode++;
+ }
+ }
+ return oflags;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lib_fdopen
+ ****************************************************************************/
+
+FAR struct file_struct *lib_fdopen(int fd, FAR const char *mode,
+ FAR struct filelist *flist,
+ FAR struct streamlist *slist)
+{
+ FAR struct inode *inode;
+ FAR FILE *stream;
+ int oflags = lib_mode2oflags(mode);
+ int err = OK;
+ int i;
+
+ /* Check input parameters */
+
+ if (fd < 0 || !flist || !slist)
+ {
+ err = EBADF;
+ goto errout;
+ }
+
+ /* Get the inode associated with the file descriptor. This should
+ * normally be the case if fd >= 0. But not in the case where the
+ * called attempts to explictly stdin with fdopen(0) but stdin has
+ * been closed.
+ */
+
+ inode = flist->fl_files[fd].f_inode;
+ if (!inode)
+ {
+ err = ENOENT;
+ goto errout;
+ }
+
+ /* Make sure that the inode supports the requested access. In
+ * the case of fdopen, we are not actually creating the file -- in
+ * particular w and w+ do not truncate the file and any files have
+ * already been created.
+ */
+
+ if (inode_checkflags(inode, oflags) != OK)
+ {
+ err = EACCES;
+ goto errout;
+ }
+
+ /* Find an unallocated FILE structure */
+
+ stream_semtake(slist);
+ for (i = 0 ; i < CONFIG_NFILE_STREAMS; i++)
+ {
+ stream = &slist->sl_streams[i];
+ if (stream->fs_filedes < 0)
+ {
+ /* Zero the structure */
+#if CONFIG_STDIO_BUFFER_SIZE > 0
+ memset(stream, 0, sizeof(FILE));
+#elif CONFIG_NUNGET_CHARS > 0
+ stream->fs_nungotten = 0;
+#endif
+
+#if CONFIG_STDIO_BUFFER_SIZE > 0
+ /* Initialize the semaphore the manages access to the buffer */
+
+ (void)sem_init(&stream->fs_sem, 0, 1);
+
+ /* Allocate the IO buffer */
+
+ stream->fs_bufstart = malloc(CONFIG_STDIO_BUFFER_SIZE);
+ if (!stream)
+ {
+ err = ENOMEM;
+ goto errout_with_sem;
+ }
+
+ /* Set up pointers */
+
+ stream->fs_bufend = &stream->fs_bufstart[CONFIG_STDIO_BUFFER_SIZE];
+ stream->fs_bufpos = stream->fs_bufstart;
+ stream->fs_bufpos = stream->fs_bufstart;
+ stream->fs_bufread = stream->fs_bufstart;
+#endif
+ /* Save the file description and open flags. Setting the
+ * file descriptor locks this stream.
+ */
+
+ stream->fs_filedes = fd;
+ stream->fs_oflags = oflags;
+
+ stream_semgive(slist);
+ return stream;
+ }
+ }
+
+#if CONFIG_STDIO_BUFFER_SIZE > 0
+errout_with_sem:
+#endif
+ stream_semgive(slist);
+
+errout:
+ *get_errno_ptr() = err;
+ return NULL;
+}
+
+/****************************************************************************
+ * Name: fdopen
+ ****************************************************************************/
+
+FAR FILE *fdopen(int fd, FAR const char *mode)
+{
+ FAR struct filelist *flist = sched_getfiles();
+ FAR struct streamlist *slist = sched_getstreams();
+ return lib_fdopen(fd, mode, flist, slist);
+}
+
+/****************************************************************************
+ * Name: fopen
+ ****************************************************************************/
+
+FAR FILE *fopen(FAR const char *path, FAR const char *mode)
+{
+ FAR FILE *ret = NULL;;
+ int oflags;
+ int fd;
+
+ /* Open the file */
+
+ oflags = lib_mode2oflags(mode);
+ 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)
+ {
+ FAR struct filelist *flist = sched_getfiles();
+ FAR struct streamlist *slist = sched_getstreams();
+
+ ret = lib_fdopen(fd, mode, flist, slist);
+ 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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