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