1  /* Read a directory.  Linux no-LFS version.
       2     Copyright (C) 2018-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <dirent.h>
      20  
      21  #if !_DIRENT_MATCHES_DIRENT64
      22  #include <dirstream.h>
      23  
      24  /* Read a directory entry from DIRP.  */
      25  struct dirent *
      26  __readdir_unlocked (DIR *dirp)
      27  {
      28    struct dirent *dp;
      29    int saved_errno = errno;
      30  
      31    if (dirp->offset >= dirp->size)
      32      {
      33        /* We've emptied out our buffer.  Refill it.  */
      34  
      35        size_t maxread = dirp->allocation;
      36        ssize_t bytes;
      37  
      38        bytes = __getdents (dirp->fd, dirp->data, maxread);
      39        if (bytes <= 0)
      40  	{
      41  	  /* Linux may fail with ENOENT on some file systems if the
      42  	     directory inode is marked as dead (deleted).  POSIX
      43  	     treats this as a regular end-of-directory condition, so
      44  	     do not set errno in that case, to indicate success.  */
      45  	  if (bytes == 0 || errno == ENOENT)
      46  	    __set_errno (saved_errno);
      47  	  return NULL;
      48  	}
      49        dirp->size = (size_t) bytes;
      50  
      51        /* Reset the offset into the buffer.  */
      52        dirp->offset = 0;
      53      }
      54  
      55    dp = (struct dirent *) &dirp->data[dirp->offset];
      56    dirp->offset += dp->d_reclen;
      57    dirp->filepos = dp->d_off;
      58  
      59    return dp;
      60  }
      61  
      62  struct dirent *
      63  __readdir (DIR *dirp)
      64  {
      65    struct dirent *dp;
      66  
      67  #if IS_IN (libc)
      68    __libc_lock_lock (dirp->lock);
      69  #endif
      70    dp = __readdir_unlocked (dirp);
      71  #if IS_IN (libc)
      72    __libc_lock_unlock (dirp->lock);
      73  #endif
      74  
      75    return dp;
      76  }
      77  weak_alias (__readdir, readdir)
      78  
      79  #endif