/* Common implementation for scandir{at}.

   Copyright (C) 2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <string.h>

#include <errno.h>

int

SCANDIR_TAIL (DIR *dp,

              DIRENT_TYPE ***namelist,

              int (*select) (const DIRENT_TYPE *),

              int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **))

{

  if (dp == NULL)

    return -1;

  int save = errno;

  __set_errno (0);

  int result;

  struct scandir_cancel_struct c = { .dp = dp };

  __libc_cleanup_push (&__scandir_cancel_handler, &c);

  DIRENT_TYPE **v = NULL;

  size_t vsize = 0;

  DIRENT_TYPE *d;

  while ((d = READDIR (dp)) != NULL)

    {

      if (select != NULL)

        {

          int selected = (*select) (d);

	  /* The SELECT function might have set errno to non-zero on

	     success.  It was zero before and it needs to be again to

	     make the later tests work.  */

	  __set_errno (0);

          if (!selected)

            continue;

        }

      if (__glibc_unlikely (c.cnt == vsize))

        {

          if (vsize == 0)

            vsize = 10;

          else

            vsize *= 2;

          DIRENT_TYPE **new = realloc (v, vsize * sizeof *v);

          if (new == NULL)

            break;

          c.v = v = new;

        }

      size_t dsize = &d->d_name[_D_ALLOC_NAMLEN (d)] - (char *) d;

      DIRENT_TYPE *vnew = malloc (dsize);

      if (vnew == NULL)

        break;

      v[c.cnt++] = (DIRENT_TYPE *) memcpy (vnew, d, dsize);

      /* Ignore errors from readdir, malloc or realloc.  These functions

	 might have set errno to non-zero on success.  It was zero before

	 and it needs to be again to make the latter tests work.  */

      __set_errno (0);

    }

  if (__glibc_likely (errno == 0))

    {

      __closedir (dp);

      /* Sort the list if we have a comparison function to sort with.  */

      if (cmp != NULL)

	qsort (v, c.cnt, sizeof *v, (__compar_fn_t) cmp);

      *namelist = v;

      result = c.cnt;

    }

  else

    {

      /* This frees everything and calls closedir.  */

      __scandir_cancel_handler (&c);

      result = -1;

    }

  __libc_cleanup_pop (0);

  if (result >= 0)

    __set_errno (save);

  return result;

}