1  /* Create a device inode.
       2     Copyright (C) 2009-2023 Free Software Foundation, Inc.
       3  
       4     This file is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU Lesser General Public License as
       6     published by the Free Software Foundation, either version 3 of the
       7     License, or (at your option) any later version.
       8  
       9     This file is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* written by Eric Blake */
      18  
      19  #include <config.h>
      20  
      21  #include <sys/stat.h>
      22  
      23  #include <errno.h>
      24  #include <string.h>
      25  
      26  #if !HAVE_MKNOD
      27  /* Mingw lacks mknod; always fail with ENOSYS.  */
      28  
      29  int
      30  mknod (_GL_UNUSED char const *name, _GL_UNUSED mode_t mode,
      31         _GL_UNUSED dev_t dev)
      32  {
      33    errno = ENOSYS;
      34    return -1;
      35  }
      36  
      37  #else /* HAVE_MKNOD */
      38  
      39  # undef mknod
      40  
      41  /* Create a file system node FILE, with access permissions and file
      42     type in MODE, and device type in DEV.  Usually, non-root
      43     applications can only create named fifos (mode includes S_IFIFO),
      44     with DEV set to 0.  Also work around trailing slash bugs.  */
      45  
      46  int
      47  rpl_mknod (char const *name, mode_t mode, dev_t dev)
      48  {
      49  # if MKFIFO_TRAILING_SLASH_BUG
      50    /* Trailing slash only makes sense for directories.  Of course,
      51       using mknod to create a directory is not very portable, so it may
      52       still fail later on.  */
      53    if (!S_ISDIR (mode))
      54      {
      55        size_t len = strlen (name);
      56        if (len && name[len - 1] == '/')
      57          {
      58            struct stat st;
      59            if (stat (name, &st) == 0 || errno == EOVERFLOW)
      60              errno = EEXIST;
      61            return -1;
      62          }
      63      }
      64  # endif
      65  # if MKNOD_FIFO_BUG
      66    /* POSIX requires mknod to create fifos for non-privileged
      67       processes, but BSD implementations fail with EPERM.  */
      68    if (S_ISFIFO (mode) && dev == 0)
      69      return mkfifo (name, mode & ~S_IFIFO);
      70  # endif
      71    return mknod (name, mode, dev);
      72  }
      73  
      74  #endif /* HAVE_MKNOD */