xref: /third_party/NuttX/fs/vfs/fs_dup2.c (revision beacf11b) 
1/****************************************************************************
2 * fs/vfs/fs_dup2.c
3 *
4 * Copyright (c) 2023 Huawei Device Co., Ltd. All rights reserved.
5 * Based on NuttX originally from nuttx source (nuttx/fs/ and nuttx/drivers/)
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 *     http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 ****************************************************************************/
20
21/****************************************************************************
22 * Included Files
23 ****************************************************************************/
24
25#include "vfs_config.h"
26
27#include "errno.h"
28#include "unistd.h"
29#include "sched.h"
30#include "vnode.h"
31
32/* This logic in this applies only when both socket and file descriptors are
33 * in that case, this function descriminates which type of dup2 is being
34 * performed.
35 */
36
37#if CONFIG_NFILE_DESCRIPTORS > 0 && defined(LOSCFG_NET_LWIP_SACK)
38
39/****************************************************************************
40 * Public Functions
41 ****************************************************************************/
42
43/****************************************************************************
44 * Name: dup2
45 *
46 * Description:
47 *   Clone a file descriptor or socket descriptor to a specific descriptor
48 *   number
49 *
50 ****************************************************************************/
51
52int dup2(int fd1, int fd2)
53{
54  /* Check the range of the descriptor to see if we got a file or a socket
55   * descriptor.
56   */
57
58  if ((unsigned int)fd1 >= CONFIG_NFILE_DESCRIPTORS)
59    {
60      /* Not a valid file descriptor.  Did we get a valid socket descriptor? */
61
62      if ((unsigned int)fd1 < (unsigned int)(CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS))
63        {
64          /* Yes.. dup the socket descriptor. The errno value is not set. */
65
66          set_errno(EBADF); /* When net_dupsd2 is still closed,errno should set */
67          return VFS_ERROR; /* LWIP not support */
68        }
69      else
70        {
71          /* No.. then it is a bad descriptor number */
72
73          set_errno(EBADF);
74          return VFS_ERROR;
75        }
76    }
77  else
78    {
79      /* Its a valid file descriptor.. dup the file descriptor.  fd_dupfd()
80       * sets the errno value in the event of any failures.
81       */
82
83      return fs_dupfd2(fd1, fd2);
84    }
85}
86
87#endif /* CONFIG_NFILE_DESCRIPTORS > 0 ... */
88