nuttx-mirror/fs/vfs/fs_dup.c

/****************************************************************************
 * fs/vfs/fs_dup.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <unistd.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>

#include <nuttx/fs/fs.h>
#include "inode/inode.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: file_dup
 *
 * Description:
 *   Equivalent to the standard dup() function except that it
 *   accepts a struct file instance instead of a file descriptor.
 *
 * Returned Value:
 *   The new file descriptor is returned on success; a negated errno value
 *   is returned on any failure.
 *
 ****************************************************************************/

int file_dup(FAR struct file *filep, int minfd, int flags)
{
  FAR struct file *filep2;
  int fd2;
  int ret;
#ifdef CONFIG_FDSAN
  uint64_t f_tag_fdsan; /* File owner fdsan tag, init to 0 */
#endif

#ifdef CONFIG_FDCHECK
  uint8_t f_tag_fdcheck; /* File owner fdcheck tag, init to 0 */
#endif

  fd2 = file_allocate(g_root_inode, 0, 0, NULL, minfd, true);
  if (fd2 < 0)
    {
      return fd2;
    }

  ret = fs_getfilep(fd2, &filep2);
#ifdef CONFIG_FDSAN
  f_tag_fdsan = filep2->f_tag_fdsan;
#endif

#ifdef CONFIG_FDCHECK
  f_tag_fdcheck = filep2->f_tag_fdcheck;
#endif
  DEBUGASSERT(ret >= 0);

  ret = file_dup3(filep, filep2, flags);
#ifdef CONFIG_FDSAN
  filep2->f_tag_fdsan = f_tag_fdsan;
#endif

#ifdef CONFIG_FDCHECK
  filep2->f_tag_fdcheck = f_tag_fdcheck;
#endif

  fs_putfilep(filep2);
  if (ret >= 0)
    {
      return fd2;
    }

  fs_putfilep(filep2);
  return ret;
}

/****************************************************************************
 * Name: dup
 *
 * Description:
 *   Clone a file or socket descriptor to an arbitrary descriptor number
 *
 ****************************************************************************/

int dup(int fd)
{
  FAR struct file *filep;
  int ret;

  /* Get the file structure corresponding to the file descriptor. */

  ret = fs_getfilep(fd, &filep);
  if (ret < 0)
    {
      goto err;
    }

  /* Let file_dup() do the real work */

  ret = file_dup(filep, 0, 0);
  fs_putfilep(filep);
  if (ret < 0)
    {
      goto err;
    }

  return ret;

err:
  set_errno(-ret);
  return ERROR;
}