nuttx/fs/vfs/fs_getfilep.c

115 lines
3.9 KiB
C

/****************************************************************************
* fs/vfs/fs_getfilep.c
*
* Copyright (C) 2014, 2016 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 <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <fcntl.h>
#include <sched.h>
#include <errno.h>
#include "inode/inode.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: fs_getfilep
*
* Description:
* Given a file descriptor, return the corresponding instance of struct
* file. NOTE that this function will currently fail if it is provided
* with a socket descriptor.
*
* Parameters:
* fd - The file descriptor
*
* Return:
* A point to the corresponding struct file instance is returned on
* success. On failure, NULL is returned and the errno value is
* set appropriately (EBADF).
*
****************************************************************************/
FAR struct file *fs_getfilep(int fd)
{
FAR struct filelist *list;
int errcode;
if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
{
errcode = EBADF;
goto errout;
}
/* The descriptor is in a valid range to file descriptor... Get the
* thread-specific file list.
*/
list = sched_getfiles();
/* The file list can be NULL under two cases: (1) One is an obscure
* cornercase: When memory management debug output is enabled. Then
* there may be attempts to write to stdout from malloc before the group
* data has been allocated. The other other is (2) if this is a kernel
* thread. Kernel threads have no allocated file descriptors.
*/
if (list == NULL)
{
errcode = EAGAIN;
goto errout;
}
/* And return the file pointer from the list */
return &list->fl_files[fd];
errout:
set_errno(errcode);
return NULL;
}