nuttx/fs/vfs/fs_dupfd.c
Gregory Nutt e4dd33280d Squashed commit of the following:
psock_close() and net_close() are internal OS functions and should not set the errno variable.

    psock_ioctl() and netdev_ioctl() are internal OS functions and should not set the errno variable.

    net_dupsd() and net_dupsd2() are internal OS functions and should not set the errno variable.

    net/ and fs/: net_vfcntl(), file_fcntl(), file_dup(), and file_dup2() are all internal OS interfaces and should not modify the errno value.
2017-09-30 10:41:21 -06:00

153 lines
4.8 KiB
C

/****************************************************************************
* fs/vfs/fs_dupfd.c
*
* Copyright (C) 2007-2009, 2011-2014, 2017 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 <sched.h>
#include <errno.h>
#include <assert.h>
#include <nuttx/fs/fs.h>
#include "inode/inode.h"
#if CONFIG_NFILE_DESCRIPTORS > 0
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define DUP_ISOPEN(filep) (filep->f_inode != NULL)
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: file_dup
*
* Description:
* Equivalent to the non-standard fs_dupfd() function except that it
* accepts a struct file instance instead of a file descriptor and does
* not set the errno variable.
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned on
* any failure.
*
****************************************************************************/
int file_dup(FAR struct file *filep, int minfd)
{
int fd2;
/* Verify that fd is a valid, open file descriptor */
if (!DUP_ISOPEN(filep))
{
return -EBADF;
}
/* Increment the reference count on the contained inode */
inode_addref(filep->f_inode);
/* Then allocate a new file descriptor for the inode */
fd2 = files_allocate(filep->f_inode, filep->f_oflags, filep->f_pos, minfd);
if (fd2 < 0)
{
inode_release(filep->f_inode);
return -EMFILE;
}
return fd2;
}
/****************************************************************************
* Name: fs_dupfd OR dup
*
* Description:
* Clone a file descriptor 'fd' to an arbitray descriptor number (any value
* greater than or equal to 'minfd'). If socket descriptors are
* implemented, then this is called by dup() for the case of file
* descriptors. If socket descriptors are not implemented, then this
* function IS dup().
*
* Returned Value:
* fs_dupfd is sometimes an OS internal function and sometimes is a direct
* substitute for dup(). So it must return an errno value as though it
* were dup().
*
****************************************************************************/
int fs_dupfd(int fd, int minfd)
{
FAR struct file *filep;
int ret;
/* Get the file structure corresponding to the file descriptor. */
filep = fs_getfilep(fd);
if (!filep)
{
/* The errno value has already been set */
return ERROR;
}
/* Let file_dup() do the real work */
ret = file_dup(filep, minfd);
if (ret < 0)
{
set_errno(-ret);
return ERROR;
}
return OK;
}
#endif /* CONFIG_NFILE_DESCRIPTORS > 0 */