forked from Archive/PX4-Autopilot
262 lines
7.2 KiB
C
262 lines
7.2 KiB
C
/****************************************************************************
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* fs/fs_fdopen.c
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*
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* Copyright (C) 2007-2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <string.h>
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#include <semaphore.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/fs.h>
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#include <nuttx/net.h>
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: fs_checkfd
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*
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* Description:
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* Check if the file descriptor is valid for the provided TCB and if it
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* supports the requested access.
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*
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****************************************************************************/
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#if CONFIG_NFILE_DESCRIPTORS > 0
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static inline int fs_checkfd(FAR _TCB *tcb, int fd, int oflags)
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{
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FAR struct filelist *flist;
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FAR struct inode *inode;
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/* Get the file list from the TCB */
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flist = tcb->filelist;
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/* Get the inode associated with the file descriptor. This should
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* normally be the case if fd >= 0. But not in the case where the
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* called attempts to explictly stdin with fdopen(0) but stdin has
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* been closed.
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*/
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inode = flist->fl_files[fd].f_inode;
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if (!inode)
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{
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/* No inode -- descriptor does not correspond to an open file */
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return -ENOENT;
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}
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/* Make sure that the inode supports the requested access. In
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* the case of fdopen, we are not actually creating the file -- in
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* particular w and w+ do not truncate the file and any files have
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* already been created.
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*/
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if (inode_checkflags(inode, oflags) != OK)
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{
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/* Cannot support the requested access */
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return -EACCES;
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}
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/* Looks good to me */
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return OK;
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}
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: fs_fdopen
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*
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* Description:
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* This function does the core operations for fopen and fdopen.
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*
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****************************************************************************/
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FAR struct file_struct *fs_fdopen(int fd, int oflags, FAR _TCB *tcb)
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{
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FAR struct streamlist *slist;
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FAR FILE *stream;
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int err = OK;
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int ret;
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int i;
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/* Check input parameters */
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if (fd < 0)
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{
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err = EBADF;
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goto errout;
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}
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/* A NULL TCB pointer means to use this threads TCB. This is a little
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* hack the let's this function be called from user-space (via a syscall)
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* without having access to the TCB.
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*/
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if (!tcb)
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{
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tcb = sched_self();
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}
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/* Verify that this is a valid file/socket descriptor and that the
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* requested access can be support.
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*
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* Is this fd in the range of valid file descriptors? Socket descriptors
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* lie in a different range.
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*/
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#if CONFIG_NFILE_DESCRIPTORS > 0
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if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
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#endif
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{
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/* No.. If networking is enabled then this might be a socket
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* descriptor.
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*/
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#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
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ret = net_checksd(fd, oflags);
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#else
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/* No networking... it is just a bad descriptor */
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err = EBADF;
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goto errout;
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#endif
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}
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/* The descriptor is in a valid range to file descriptor... do the read */
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#if CONFIG_NFILE_DESCRIPTORS > 0
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else
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{
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ret = fs_checkfd(tcb, fd, oflags);
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}
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#endif
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/* Do we have a good descriptor of some sort? */
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if (ret < 0)
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{
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/* No... return the reported error */
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err = -ret;
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goto errout;
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}
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/* Get the stream list from the TCB */
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slist = tcb->streams;
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/* Find an unallocated FILE structure in the stream list */
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ret = sem_wait(&slist->sl_sem);
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if (ret != OK)
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{
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goto errout_with_errno;
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}
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for (i = 0 ; i < CONFIG_NFILE_STREAMS; i++)
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{
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stream = &slist->sl_streams[i];
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if (stream->fs_filedes < 0)
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{
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/* Zero the structure */
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#if CONFIG_STDIO_BUFFER_SIZE > 0
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memset(stream, 0, sizeof(FILE));
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#elif CONFIG_NUNGET_CHARS > 0
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stream->fs_nungotten = 0;
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#endif
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#if CONFIG_STDIO_BUFFER_SIZE > 0
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/* Initialize the semaphore the manages access to the buffer */
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(void)sem_init(&stream->fs_sem, 0, 1);
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/* Allocate the IO buffer */
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stream->fs_bufstart = kmalloc(CONFIG_STDIO_BUFFER_SIZE);
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if (!stream)
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{
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err = ENOMEM;
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goto errout_with_sem;
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}
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/* Set up pointers */
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stream->fs_bufend = &stream->fs_bufstart[CONFIG_STDIO_BUFFER_SIZE];
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stream->fs_bufpos = stream->fs_bufstart;
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stream->fs_bufpos = stream->fs_bufstart;
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stream->fs_bufread = stream->fs_bufstart;
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#endif
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/* Save the file description and open flags. Setting the
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* file descriptor locks this stream.
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*/
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stream->fs_filedes = fd;
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stream->fs_oflags = oflags;
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sem_post(&slist->sl_sem);
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return stream;
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}
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}
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/* No free stream available.. report ENFILE */
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err = ENFILE;
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#if CONFIG_STDIO_BUFFER_SIZE > 0
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errout_with_sem:
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#endif
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sem_post(&slist->sl_sem);
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errout:
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set_errno(err);
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errout_with_errno:
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return NULL;
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}
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