1  /* Create an inode relative to an open directory.
       2     Copyright (C) 2009-2023 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation, either version 3 of the License, or
       7     (at your option) any later version.
       8  
       9     This program 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 General Public License for more details.
      13  
      14     You should have received a copy of the GNU 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  /* Specification.  */
      22  #include <sys/stat.h>
      23  
      24  #include <stdlib.h>
      25  
      26  #if HAVE_MKNODAT
      27  
      28  # include <errno.h>
      29  # include <fcntl.h>
      30  # include <string.h>
      31  
      32  int
      33  rpl_mknodat (int fd, char const *file, mode_t mode, dev_t dev)
      34  #undef mknodat
      35  {
      36    /* Use the original mknodat(), but correct the trailing slash handling.  */
      37    size_t len = strlen (file);
      38    if (len && file[len - 1] == '/')
      39      {
      40        struct stat st;
      41  
      42        if (fstatat (fd, file, &st, AT_SYMLINK_NOFOLLOW) < 0)
      43          {
      44            if (errno == EOVERFLOW)
      45              /* It's surely a file, not a directory.  */
      46              errno = ENOTDIR;
      47          }
      48        else
      49          {
      50            /* It's a directory, otherwise fstatat() would have reported an error
      51               ENOTDIR.  */
      52            errno = EEXIST;
      53          }
      54        return -1;
      55      }
      56  
      57    return mknodat (fd, file, mode, dev);
      58  }
      59  
      60  #else
      61  
      62  # if !HAVE_MKNOD
      63  
      64  #  include <errno.h>
      65  
      66  /* Mingw lacks mknod, so this wrapper is trivial.  */
      67  
      68  int
      69  mknodat (_GL_UNUSED int fd, _GL_UNUSED char const *path,
      70           _GL_UNUSED mode_t mode, _GL_UNUSED dev_t dev)
      71  {
      72    errno = ENOSYS;
      73    return -1;
      74  }
      75  
      76  # else
      77  
      78  /* Create a file system node FILE relative to directory FD, with
      79     access permissions and file type in MODE, and device type in DEV.
      80     Usually, non-root applications can only create named fifos, with
      81     DEV set to 0.  If possible, create the node without changing the
      82     working directory.  Otherwise, resort to using save_cwd/fchdir,
      83     then mknod/restore_cwd.  If either the save_cwd or the restore_cwd
      84     fails, then give a diagnostic and exit nonzero.  */
      85  
      86  #  define AT_FUNC_NAME mknodat
      87  #  define AT_FUNC_F1 mknod
      88  #  define AT_FUNC_POST_FILE_PARAM_DECLS , mode_t mode, dev_t dev
      89  #  define AT_FUNC_POST_FILE_ARGS        , mode, dev
      90  #  include "at-func.c"
      91  #  undef AT_FUNC_NAME
      92  #  undef AT_FUNC_F1
      93  #  undef AT_FUNC_POST_FILE_PARAM_DECLS
      94  #  undef AT_FUNC_POST_FILE_ARGS
      95  
      96  # endif
      97  
      98  #endif