sysdeps/mach/hurd/readdir64.c

   1 /* Copyright (C) 2001-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <dirent.h>
  19 #include <stddef.h>
  20 #include <hurd.h>
  21 #include <hurd/fs.h>
  22 #include <hurd/fd.h>
  23 #include "dirstream.h"
  24
  25 /* Read a directory entry from DIRP.  */
  26 struct dirent64 *
  27 __readdir64 (DIR *dirp)
  28 {
  29   struct dirent64 *dp;
  30
  31   if (dirp == NULL)
  32     return __hurd_fail (EINVAL), NULL;
  33
  34   __libc_lock_lock (dirp->__lock);
  35
  36   do
  37     {
  38       if (dirp->__ptr - dirp->__data >= dirp->__size)
  39         {
  40           /* We've emptied out our buffer.  Refill it.  */
  41
  42           char *data = dirp->__data;
  43           mach_msg_type_number_t data_size = dirp->__size;
  44           int nentries;
  45           error_t err;
  46
  47           if (err = HURD_FD_PORT_USE (dirp->__fd,
  48                                       __dir_readdir (port,
  49                                                      &data, &data_size,
  50                                                      dirp->__entry_ptr,
  51                                                      -1, 0, &nentries)))
  52             {
  53               __hurd_fail (err);
  54               dp = NULL;
  55               break;
  56             }
  57
  58           dirp->__size = data_size;
  59           /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
  60           dirp->__entry_data = dirp->__entry_ptr;
  61
  62           if (data != dirp->__data)
  63             {
  64               /* The data was passed out of line, so our old buffer is no
  65                  longer useful.  Deallocate the old buffer and reset our
  66                  information for the new buffer.  */
  67               if (dirp->__data != NULL)
  68                 {
  69                   err = __vm_deallocate (__mach_task_self (),
  70                                          (vm_address_t) dirp->__data,
  71                                          dirp->__allocation);
  72                   assert_perror (err);
  73                 }
  74               dirp->__data = data;
  75               dirp->__allocation = round_page (dirp->__size);
  76             }
  77
  78           /* Reset the pointer into the buffer.  */
  79           dirp->__ptr = dirp->__data;
  80
  81           if (nentries == 0)
  82             {
  83               /* End of file.  */
  84               dp = NULL;
  85               break;
  86             }
  87
  88           /* We trust the filesystem to return correct data and so we
  89              ignore NENTRIES.  */
  90         }
  91
  92       dp = (struct dirent64 *) dirp->__ptr;
  93       dirp->__ptr += dp->d_reclen;
  94       ++dirp->__entry_ptr;
  95
  96       /* Loop to ignore deleted files.  */
  97     } while (dp->d_fileno == 0);
  98
  99   __libc_lock_unlock (dirp->__lock);
 100
 101   return dp;
 102 }
 103
 104 libc_hidden_def (__readdir64)
 105 weak_alias (__readdir64, readdir64)