sysdeps/mach/hurd/readdir.c

   1 /* Copyright (C) 1993, 1994, 1995, 1996 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <limits.h>
  22 #include <stddef.h>
  23 #include <string.h>
  24 #include <dirent.h>
  25 #include <unistd.h>
  26 #include <sys/types.h>
  27 #include <hurd.h>
  28 #include <hurd/fd.h>
  29 #include "dirstream.h"
  30
  31
  32 /* Read a directory entry from DIRP.  */
  33 struct dirent *
  34 DEFUN(readdir, (dirp), DIR *dirp)
  35 {
  36   struct dirent *dp;
  37
  38   if (dirp == NULL)
  39     {
  40       errno = EINVAL;
  41       return NULL;
  42     }
  43
  44   __libc_lock_lock (dirp->__lock);
  45
  46   do
  47     {
  48       if (dirp->__ptr - dirp->__data >= dirp->__size)
  49         {
  50           /* We've emptied out our buffer.  Refill it.  */
  51
  52           char *data = dirp->__data;
  53           int nentries;
  54           error_t err;
  55
  56           if (err = HURD_FD_PORT_USE (dirp->__fd,
  57                                       __dir_readdir (port,
  58                                                      &data, &dirp->__size,
  59                                                      dirp->__entry_ptr,
  60                                                      -1, 0, &nentries)))
  61             {
  62               __hurd_fail (err);
  63               dp = NULL;
  64               break;
  65             }
  66
  67           /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
  68           dirp->__entry_data = dirp->__entry_ptr;
  69
  70           if (data != dirp->__data)
  71             {
  72               /* The data was passed out of line, so our old buffer is no
  73                  longer useful.  Deallocate the old buffer and reset our
  74                  information for the new buffer.  */
  75               __vm_deallocate (__mach_task_self (),
  76                                (vm_address_t) dirp->__data,
  77                                dirp->__allocation);
  78               dirp->__data = data;
  79               dirp->__allocation = round_page (dirp->__size);
  80             }
  81
  82           /* Reset the pointer into the buffer.  */
  83           dirp->__ptr = dirp->__data;
  84
  85           if (nentries == 0)
  86             {
  87               /* End of file.  */
  88               dp = NULL;
  89               break;
  90             }
  91
  92           /* We trust the filesystem to return correct data and so we
  93              ignore NENTRIES.  */
  94         }
  95
  96       dp = (struct dirent *) dirp->__ptr;
  97       dirp->__ptr += dp->d_reclen;
  98       ++dirp->__entry_ptr;
  99
 100       /* Loop to ignore deleted files.  */
 101     } while (dp->d_fileno == 0);
 102
 103   __libc_lock_unlock (dirp->__lock);
 104
 105   return dp;
 106 }