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 <errno.h>
  20 #include <limits.h>
  21 #include <stddef.h>
  22 #include <string.h>
  23 #include <dirent.h>
  24 #include <unistd.h>
  25 #include <sys/types.h>
  26 #include <hurd.h>
  27 #include <hurd/fd.h>
  28 #include "dirstream.h"
  29
  30
  31 /* Read a directory entry from DIRP.  */
  32 struct dirent *
  33 __readdir (DIR *dirp)
  34 {
  35   struct dirent *dp;
  36
  37   if (dirp == NULL)
  38     {
  39       errno = EINVAL;
  40       return NULL;
  41     }
  42
  43   __libc_lock_lock (dirp->__lock);
  44
  45   do
  46     {
  47       if (dirp->__ptr - dirp->__data >= dirp->__size)
  48         {
  49           /* We've emptied out our buffer.  Refill it.  */
  50
  51           char *data = dirp->__data;
  52           int nentries;
  53           error_t err;
  54
  55           if (err = HURD_FD_PORT_USE (dirp->__fd,
  56                                       __dir_readdir (port,
  57                                                      &data, &dirp->__size,
  58                                                      dirp->__entry_ptr,
  59                                                      -1, 0, &nentries)))
  60             {
  61               __hurd_fail (err);
  62               dp = NULL;
  63               break;
  64             }
  65
  66           /* DATA now corresponds to entry index DIRP->__entry_ptr.  */
  67           dirp->__entry_data = dirp->__entry_ptr;
  68
  69           if (data != dirp->__data)
  70             {
  71               /* The data was passed out of line, so our old buffer is no
  72                  longer useful.  Deallocate the old buffer and reset our
  73                  information for the new buffer.  */
  74               __vm_deallocate (__mach_task_self (),
  75                                (vm_address_t) dirp->__data,
  76                                dirp->__allocation);
  77               dirp->__data = data;
  78               dirp->__allocation = round_page (dirp->__size);
  79             }
  80
  81           /* Reset the pointer into the buffer.  */
  82           dirp->__ptr = dirp->__data;
  83
  84           if (nentries == 0)
  85             {
  86               /* End of file.  */
  87               dp = NULL;
  88               break;
  89             }
  90
  91           /* We trust the filesystem to return correct data and so we
  92              ignore NENTRIES.  */
  93         }
  94
  95       dp = (struct dirent *) dirp->__ptr;
  96       dirp->__ptr += dp->d_reclen;
  97       ++dirp->__entry_ptr;
  98
  99       /* Loop to ignore deleted files.  */
 100     } while (dp->d_fileno == 0);
 101
 102   __libc_lock_unlock (dirp->__lock);
 103
 104   return dp;
 105 }
 106 weak_alias (__readdir, readdir)