[PATCH 1/3] io: Consolidate fts implementation

Adhemerval Zanella Netto adhemerval.zanella@linaro.org
Fri Apr 17 17:31:13 GMT 2026


This is a mechanical patch and I install if no one opposes it.

On 17/04/26 10:24, Adhemerval Zanella wrote:
> Remove wordsize-64 and arch-specific implementations, for ABIs when
> off_t is the same as off64_t (__OFF_T_MATCHES_OFF64_T) the fts64.c
> will create the requires aliases.
> 
> The fts.c implementation is moved to fts-common.c to simplify
> the __OFF_T_MATCHES_OFF64_T usage.
> ---
>  SHARED-FILES                                  |    2 +-
>  io/fts-common.c                               | 2208 ++++++++++++++++
>  io/fts.c                                      | 2217 +----------------
>  io/fts64-time64.c                             |    2 +-
>  io/fts64.c                                    |   38 +-
>  sysdeps/unix/sysv/linux/mips/mips64/n64/fts.c |    1 -
>  .../unix/sysv/linux/mips/mips64/n64/fts64.c   |    1 -
>  sysdeps/unix/sysv/linux/x86_64/x32/fts.c      |    1 -
>  sysdeps/unix/sysv/linux/x86_64/x32/fts64.c    |    1 -
>  sysdeps/wordsize-64/fts.c                     |   19 -
>  sysdeps/wordsize-64/fts64.c                   |    1 -
>  11 files changed, 2258 insertions(+), 2233 deletions(-)
>  create mode 100644 io/fts-common.c
>  delete mode 100644 sysdeps/unix/sysv/linux/mips/mips64/n64/fts.c
>  delete mode 100644 sysdeps/unix/sysv/linux/mips/mips64/n64/fts64.c
>  delete mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/fts.c
>  delete mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/fts64.c
>  delete mode 100644 sysdeps/wordsize-64/fts.c
>  delete mode 100644 sysdeps/wordsize-64/fts64.c
> 
> diff --git a/SHARED-FILES b/SHARED-FILES
> index 126aaf096d..645040d7e1 100644
> --- a/SHARED-FILES
> +++ b/SHARED-FILES
> @@ -49,7 +49,7 @@ gnulib:
>    io/cycle-check.h
>    io/dev-ino.h
>    io/fts-cycle.c
> -  io/fts.c
> +  io/fts-common.c
>    io/i-ring.c
>    io/same-inode.h
>    locale/programs/3level.h
> diff --git a/io/fts-common.c b/io/fts-common.c
> new file mode 100644
> index 0000000000..3825f0aeb4
> --- /dev/null
> +++ b/io/fts-common.c
> @@ -0,0 +1,2208 @@
> +/* Traverse a file hierarchy.
> +
> +   Copyright (C) 2004-2026 Free Software Foundation, Inc.
> +
> +   This file 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.
> +
> +   This file 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */
> +
> +/*-
> + * Copyright (c) 1990, 1993, 1994
> + *      The Regents of the University of California.  All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + *    notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + *    notice, this list of conditions and the following disclaimer in the
> + *    documentation and/or other materials provided with the distribution.
> + * 4. Neither the name of the University nor the names of its contributors
> + *    may be used to endorse or promote products derived from this software
> + *    without specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE.
> + */
> +
> +#include <config.h>
> +
> +#if defined LIBC_SCCS && !defined GCC_LINT && !defined lint
> +static char sccsid[] = "@(#)fts.c       8.6 (Berkeley) 8/14/94";
> +#endif
> +
> +#if _LIBC
> +# include <fts.h>
> +#else
> +# include "fts_.h"
> +#endif
> +#if _LIBC || HAVE_SYS_PARAM_H
> +# include <sys/param.h>
> +#endif
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <errno.h>
> +#include <stddef.h>
> +#include <stdint.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +
> +/* Support for the LFS API version.  */
> +#ifndef FTS_OPEN
> +# define FTS_OPEN fts_open
> +# define FTS_CLOSE fts_close
> +# define FTS_READ fts_read
> +# define FTS_SET fts_set
> +# define FTS_CHILDREN fts_children
> +# define FTSOBJ FTS
> +# define FTSENTRY FTSENT
> +# define INO_T ino_t
> +# define STRUCT_STAT stat
> +# define FSTAT __fstat
> +# define FSTATAT __fstatat
> +# define STRUCT_STATFS statfs
> +# define FSTATFS __fstatfs
> +#endif
> +
> +#if ! _LIBC
> +# include "attribute.h"
> +# include "fcntl--.h"
> +# include "openat.h"
> +# include "opendirat.h"
> +# include "same-inode.h"
> +# define OPENDIRAT opendirat
> +# define FTSENT_WRAPPER(__p) __p
> +# define FTS_COMPAR_CAST(__fn) __fn
> +#else
> +# include <stdbool.h>
> +
> +# define internal_function
> +# define FALLTHROUGH               ; [[fallthrough]]
> +# define HAVE_STRUCT_DIRENT_D_TYPE 1
> +# define GNULIB_FTS_DEBUG          0
> +# ifdef O_PATH
> +#  define O_SEARCH                 O_PATH
> +# else
> +#  define O_SEARCH                 O_RDONLY
> +# endif
> +# define HAVE_SYS_VFS_H            1
> +# define HAVE_FSTATFS              1
> +# define HAVE_STRUCT_STATFS_F_TYPE 1
> +# define HAVE_OPENAT               1
> +# define HAVE_WORKING_O_NOFOLLOW   1
> +# define _GL_CMP(a, b)             ((a) < (b) ? -1 : (a) > (b))
> +# define OPENDIRAT                 __opendirat
> +
> +static inline bool openat_needs_fchdir (void)
> +{
> +  return false;
> +}
> +
> +static inline bool streq (const char *s1, const char *s2)
> +{
> +  return strcmp (s1, s2) == 0;
> +}
> +# define reallocarray              __libc_reallocarray
> +# define fchdir                    __fchdir
> +# define close                     __close
> +# define closedir                  __closedir
> +# define fcntl                     __fcntl
> +# define readdir                   __readdir
> +# ifndef dirfd
> +#  define dirfd                    __dirfd
> +# endif
> +# define open                      __open
> +# define openat                    __openat
> +
> +# include "cycle-check.c"
> +# include "i-ring.c"
> +
> +struct FTSENT_wrapper
> +{
> +  FTSOBJ *fts_fts;                /* the file hierarchy itself */
> +  DIR *fts_dirp;                  /* Dir pointer for any directory containing
> +				     more entries than we read at one time.  */
> +  struct STRUCT_STAT fts_stat;
> +
> +  FTSENTRY ent;
> +};
> +
> +/* glibc historicaly defines the FTS::fts_compar as having 'void *', while the
> +   fts_open has a function point using 'FTSENT **' as argument.  */
> +# define FTS_COMPAR_CAST(__fn) ((int (*) (void const *, void const *))__fn)
> +
> +# define FTSENT_WRAPPER(p) \
> +    ((struct FTSENT_wrapper *) ((char *)(p) - offsetof(struct FTSENT_wrapper, ent)))
> +#endif
> +#define FTSENT_FTS(p)   (FTSENT_WRAPPER(p)->fts_fts)
> +#define FTSENT_DIRP(p)  (FTSENT_WRAPPER(p)->fts_dirp)
> +
> +#include "flexmember.h"
> +
> +#include <dirent.h>
> +#ifndef _D_EXACT_NAMLEN
> +# define _D_EXACT_NAMLEN(dirent) strlen ((dirent)->d_name)
> +#endif
> +
> +#if HAVE_STRUCT_DIRENT_D_TYPE
> +/* True if the type of the directory entry D is known.  */
> +# define DT_IS_KNOWN(d) ((d)->d_type != DT_UNKNOWN)
> +/* True if the type of the directory entry D must be T.  */
> +# define DT_MUST_BE(d, t) ((d)->d_type == (t))
> +# define D_TYPE(d) ((d)->d_type)
> +#else
> +# define DT_IS_KNOWN(d) false
> +# define DT_MUST_BE(d, t) false
> +# define D_TYPE(d) DT_UNKNOWN
> +
> +# undef DT_UNKNOWN
> +# define DT_UNKNOWN 0
> +
> +/* Any nonzero values will do here, so long as they're distinct.
> +   Undef any existing macros out of the way.  */
> +# undef DT_BLK
> +# undef DT_CHR
> +# undef DT_DIR
> +# undef DT_FIFO
> +# undef DT_LNK
> +# undef DT_REG
> +# undef DT_SOCK
> +# define DT_BLK 1
> +# define DT_CHR 2
> +# define DT_DIR 3
> +# define DT_FIFO 4
> +# define DT_LNK 5
> +# define DT_REG 6
> +# define DT_SOCK 7
> +#endif
> +
> +#ifndef S_IFBLK
> +# define S_IFBLK 0
> +#endif
> +#ifndef S_IFLNK
> +# define S_IFLNK 0
> +#endif
> +#ifndef S_IFSOCK
> +# define S_IFSOCK 0
> +#endif
> +
> +enum
> +{
> +  NOT_AN_INODE_NUMBER = 0
> +};
> +
> +#ifdef D_INO_IN_DIRENT
> +# define D_INO(dp) (dp)->d_ino
> +#else
> +/* Some systems don't have inodes, so fake them to avoid lots of ifdefs.  */
> +# define D_INO(dp) NOT_AN_INODE_NUMBER
> +#endif
> +
> +/* If possible (see max_entries, below), read no more than this many directory
> +   entries at a time.  Without this limit (i.e., when using non-NULL
> +   fts_compar), processing a directory with 4,000,000 entries requires ~1GiB
> +   of memory, and handling 64M entries would require 16GiB of memory.  */
> +#ifndef FTS_MAX_READDIR_ENTRIES
> +# define FTS_MAX_READDIR_ENTRIES 100000
> +#endif
> +
> +/* If there are more than this many entries in a directory,
> +   and the conditions mentioned below are satisfied, then sort
> +   the entries on inode number before any further processing.  */
> +#ifndef FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
> +# define FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD 10000
> +#endif
> +
> +enum
> +{
> +  _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD = FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
> +};
> +
> +enum Fts_stat
> +{
> +  FTS_NO_STAT_REQUIRED = 1,
> +  FTS_STAT_REQUIRED = 2
> +};
> +
> +#ifndef __set_errno
> +# define __set_errno(Val) errno = (Val)
> +#endif
> +
> +/* If this host provides the openat function, then we can avoid
> +   attempting to open "." in some initialization code below.  */
> +#ifdef HAVE_OPENAT
> +# define HAVE_OPENAT_SUPPORT 1
> +#else
> +# define HAVE_OPENAT_SUPPORT 0
> +#endif
> +
> +#ifdef NDEBUG
> +# define fts_assert(expr) ((void) (0 && (expr)))
> +#else
> +# define fts_assert(expr)       \
> +    do                          \
> +      {                         \
> +        if (!(expr))            \
> +          abort ();             \
> +      }                         \
> +    while (false)
> +#endif
> +
> +static FTSENTRY  *fts_alloc (FTSOBJ *, const char *, size_t);
> +static FTSENTRY  *fts_build (FTSOBJ *, int);
> +static void      fts_lfree (FTSENTRY *);
> +static void      fts_load (FTSOBJ *, FTSENTRY *);
> +static size_t    fts_maxarglen (char * const *);
> +static void      fts_padjust (FTSOBJ *, FTSENTRY *);
> +static bool      fts_palloc (FTSOBJ *, size_t);
> +static FTSENTRY  *fts_sort (FTSOBJ *, FTSENTRY *, size_t);
> +static unsigned short int fts_stat (FTSOBJ *, FTSENTRY *, bool);
> +static int      fts_safe_changedir (FTSOBJ *, FTSENTRY *, int, const char *);
> +
> +#include "fts-cycle.c"
> +
> +#ifndef MAX
> +# define MAX(a,b) ((a) > (b) ? (a) : (b))
> +#endif
> +
> +#ifndef SIZE_MAX
> +# define SIZE_MAX ((size_t) -1)
> +#endif
> +
> +#define ISDOT(a)        (a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
> +
> +#define CLR(opt)        (sp->fts_options &= ~(opt))
> +#define ISSET(opt)      ((sp->fts_options & (opt)) != 0)
> +#define SET(opt)        (sp->fts_options |= (opt))
> +
> +/* FIXME: FTS_NOCHDIR is now misnamed.
> +   Call it FTS_USE_FULL_RELATIVE_FILE_NAMES instead. */
> +#define FCHDIR(sp, fd)                                  \
> +  (!ISSET(FTS_NOCHDIR) && (ISSET(FTS_CWDFD)             \
> +                           ? (cwd_advance_fd ((sp), (fd), true), 0) \
> +                           : fchdir (fd)))
> +
> +
> +/* fts_build flags */
> +/* FIXME: make this an enum */
> +#define BCHILD          1               /* fts_children */
> +#define BNAMES          2               /* fts_children, names only */
> +#define BREAD           3               /* fts_read */
> +
> +#if GNULIB_FTS_DEBUG
> +# include <inttypes.h>
> +# include <stdio.h>
> +bool fts_debug = false;
> +# define Dprintf(x) do { if (fts_debug) printf x; } while (false)
> +static void fd_ring_check (FTSOBJ const *);
> +static void fd_ring_print (FTSOBJ const *, FILE *, char const *);
> +#else
> +# define Dprintf(x)
> +# define fd_ring_check(x)
> +# define fd_ring_print(a, b, c)
> +#endif
> +
> +#define LEAVE_DIR(Fts, Ent, Tag)                                \
> +  do                                                            \
> +    {                                                           \
> +      Dprintf (("  %s-leaving: %s\n", Tag, (Ent)->fts_path));   \
> +      leave_dir (Fts, Ent);                                     \
> +      fd_ring_check (Fts);                                      \
> +    }                                                           \
> +  while (false)
> +
> +static void
> +fd_ring_clear (I_ring *fd_ring)
> +{
> +  while ( ! i_ring_empty (fd_ring))
> +    {
> +      int fd = i_ring_pop (fd_ring);
> +      if (0 <= fd)
> +        close (fd);
> +    }
> +}
> +
> +/* Overload the fts_statp->st_size member (otherwise unused, when
> +   fts_info is FTS_NSOK) to indicate whether fts_read should stat
> +   this entry or not.  */
> +static void
> +fts_set_stat_required (FTSENTRY *p, bool required)
> +{
> +  fts_assert (p->fts_info == FTS_NSOK);
> +  p->fts_statp->st_size = (required
> +                           ? FTS_STAT_REQUIRED
> +                           : FTS_NO_STAT_REQUIRED);
> +}
> +
> +/* Virtual fchdir.  Advance SP's working directory file descriptor,
> +   SP->fts_cwd_fd, to FD, and push the previous value onto the fd_ring.
> +   CHDIR_DOWN_ONE is true if FD corresponds to an entry in the directory
> +   open on sp->fts_cwd_fd; i.e., to move the working directory one level
> +   down.  */
> +static void
> +internal_function
> +cwd_advance_fd (FTSOBJ *sp, int fd, bool chdir_down_one)
> +{
> +  int old = sp->fts_cwd_fd;
> +  fts_assert (old != fd || old == AT_FDCWD);
> +
> +  if (chdir_down_one)
> +    {
> +      /* Push "old" onto the ring.
> +         If the displaced file descriptor is non-negative, close it.  */
> +      int prev_fd_in_slot = i_ring_push (&sp->fts_fd_ring, old);
> +      fd_ring_print (sp, stderr, "post-push");
> +      if (0 <= prev_fd_in_slot)
> +        close (prev_fd_in_slot); /* ignore any close failure */
> +    }
> +  else if ( ! ISSET (FTS_NOCHDIR))
> +    {
> +      if (0 <= old)
> +        close (old); /* ignore any close failure */
> +    }
> +
> +  sp->fts_cwd_fd = fd;
> +}
> +
> +/* Restore the initial, pre-traversal, "working directory".
> +   In FTS_CWDFD mode, we merely call cwd_advance_fd, otherwise,
> +   we may actually change the working directory.
> +   Return 0 upon success. Upon failure, set errno and return nonzero.  */
> +static int
> +restore_initial_cwd (FTSOBJ *sp)
> +{
> +  int fail = FCHDIR (sp, ISSET (FTS_CWDFD) ? AT_FDCWD : sp->fts_rfd);
> +  fd_ring_clear (&(sp->fts_fd_ring));
> +  return fail;
> +}
> +
> +/* Open the directory DIR if possible, and return a file
> +   descriptor.  Return -1 and set errno on failure.  It doesn't matter
> +   whether the file descriptor has read or write access.  */
> +
> +static int
> +internal_function
> +diropen (FTSOBJ const *sp, char const *dir)
> +{
> +  int open_flags = (O_SEARCH | O_CLOEXEC | O_DIRECTORY | O_NOCTTY | O_NONBLOCK
> +                    | (ISSET (FTS_PHYSICAL) ? O_NOFOLLOW : 0));
> +
> +  int fd = (ISSET (FTS_CWDFD)
> +            ? openat (sp->fts_cwd_fd, dir, open_flags)
> +            : open (dir, open_flags));
> +  return fd;
> +}
> +
> +FTSOBJ *
> +FTS_OPEN (char * const *argv,
> +          register int options,
> +          int (*compar) (const FTSENTRY **, const FTSENTRY **))
> +{
> +        /* Options check: glibc added other flags after FTS_NAMEONLY and
> +	   FTS_STOP, and they are assumed to be private.  */
> +        if (options & ~FTS_OPTIONMASK
> +#if _LIBC
> +	    || options & (FTS_NAMEONLY | FTS_STOP)
> +#endif
> +	    ) {
> +                __set_errno (EINVAL);
> +                return (NULL);
> +        }
> +        if ((options & FTS_NOCHDIR) && (options & FTS_CWDFD)) {
> +                __set_errno (EINVAL);
> +                return (NULL);
> +        }
> +#if !_LIBC
> +        if ( ! (options & (FTS_LOGICAL | FTS_PHYSICAL))) {
> +                __set_errno (EINVAL);
> +                return (NULL);
> +        }
> +#else
> +	/* glibc historically falls to FTS_PHYSICAL if no FTS_PHYSICAL or
> +	   FTS_LOGICAL is specified.  */
> +        if (! (options & (FTS_PHYSICAL | FTS_LOGICAL)))
> +	  options |= FTS_PHYSICAL;
> +#endif
> +
> +        /* Allocate/initialize the stream */
> +        register FTSOBJ *sp = calloc (1, sizeof *sp);
> +        if (sp == NULL)
> +                return (NULL);
> +        sp->fts_compar = FTS_COMPAR_CAST(compar);
> +        sp->fts_options = options;
> +
> +        /* Logical walks turn on NOCHDIR; symbolic links are too hard. */
> +        if (ISSET(FTS_LOGICAL)) {
> +                SET(FTS_NOCHDIR);
> +                CLR(FTS_CWDFD);
> +        }
> +
> +        /* Initialize fts_cwd_fd.  */
> +        sp->fts_cwd_fd = AT_FDCWD;
> +        if ( ISSET(FTS_CWDFD) && ! HAVE_OPENAT_SUPPORT)
> +          {
> +            /* While it isn't technically necessary to open "." this
> +               early, doing it here saves us the trouble of ensuring
> +               later (where it'd be messier) that "." can in fact
> +               be opened.  If not, revert to FTS_NOCHDIR mode.  */
> +            int fd = open (".", O_SEARCH | O_CLOEXEC);
> +            if (fd < 0)
> +              {
> +                /* Even if "." is unreadable, don't revert to FTS_NOCHDIR mode
> +                   on systems like Linux+PROC_FS, where our openat emulation
> +                   is good enough.  Note: on a system that emulates
> +                   openat via /proc, this technique can still fail, but
> +                   only in extreme conditions, e.g., when the working
> +                   directory cannot be saved (i.e. save_cwd fails) --
> +                   and that happens on Linux only when "." is unreadable
> +                   and the CWD would be longer than PATH_MAX.
> +                   FIXME: once Linux kernel openat support is well established,
> +                   replace the above open call and this entire if/else block
> +                   with the body of the if-block below.  */
> +                if ( openat_needs_fchdir ())
> +                  {
> +                    SET(FTS_NOCHDIR);
> +                    CLR(FTS_CWDFD);
> +                  }
> +              }
> +            else
> +              {
> +                close (fd);
> +              }
> +          }
> +
> +        /*
> +         * Start out with 1K of file name space, and enough, in any case,
> +         * to hold the user's file names.
> +         */
> +#ifndef MAXPATHLEN
> +# define MAXPATHLEN 1024
> +#endif
> +        {
> +          size_t maxarglen = fts_maxarglen(argv);
> +          if (! fts_palloc(sp, MAX(maxarglen, MAXPATHLEN)))
> +                  goto mem1;
> +        }
> +
> +        /* Allocate/initialize root's parent. */
> +        FTSENTRY *parent = NULL;
> +        if (*argv != NULL) {
> +                if ((parent = fts_alloc(sp, "", 0)) == NULL)
> +                        goto mem2;
> +                parent->fts_level = FTS_ROOTPARENTLEVEL;
> +          }
> +
> +        /* The classic fts implementation would call fts_stat with
> +           a new entry for each iteration of the loop below.
> +           If the comparison function is not specified or if the
> +           FTS_DEFER_STAT option is in effect, don't stat any entry
> +           in this loop.  This is an attempt to minimize the interval
> +           between the initial stat/lstat/fstatat and the point at which
> +           a directory argument is first opened.  This matters for any
> +           directory command line argument that resides on a file system
> +           without genuine i-nodes.  If you specify FTS_DEFER_STAT along
> +           with a comparison function, that function must not access any
> +           data via the fts_statp pointer.  */
> +        bool defer_stat = (compar == NULL || ISSET(FTS_DEFER_STAT));
> +
> +        /* Allocate/initialize root(s). */
> +        register FTSENTRY *root;
> +        register size_t nitems;
> +        FTSENTRY *tmp = NULL;     /* pacify gcc */
> +        for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
> +                /* *Do* allow zero-length file names. */
> +                size_t len = strlen(*argv);
> +
> +                if ( ! (options & FTS_VERBATIM))
> +                  {
> +                    /* If there are two or more trailing slashes, trim all but one,
> +                       but don't change "//" to "/", and do map "///" to "/".  */
> +                    char const *v = *argv;
> +                    if (2 < len && v[len - 1] == '/')
> +                      while (1 < len && v[len - 2] == '/')
> +                        --len;
> +                  }
> +
> +                register FTSENTRY *p = fts_alloc(sp, *argv, len);
> +                if (p == NULL)
> +                        goto mem3;
> +                p->fts_level = FTS_ROOTLEVEL;
> +                p->fts_parent = parent;
> +                p->fts_accpath = p->fts_name;
> +                /* Even when defer_stat is true, be sure to stat the first
> +                   command line argument, since fts_read (at least with
> +                   FTS_XDEV) requires that.  */
> +                if (defer_stat && root != NULL) {
> +                        p->fts_info = FTS_NSOK;
> +                        fts_set_stat_required(p, true);
> +                } else {
> +                        p->fts_info = fts_stat(sp, p, false);
> +                }
> +
> +                /*
> +                 * If comparison routine supplied, traverse in sorted
> +                 * order; otherwise traverse in the order specified.
> +                 */
> +                if (compar) {
> +                        p->fts_link = root;
> +                        root = p;
> +                } else {
> +                        p->fts_link = NULL;
> +                        if (root == NULL)
> +                                tmp = root = p;
> +                        else {
> +                                tmp->fts_link = p;
> +                                tmp = p;
> +                        }
> +                }
> +        }
> +        if (compar && nitems > 1)
> +                root = fts_sort(sp, root, nitems);
> +
> +        /*
> +         * Allocate a dummy pointer and make fts_read think that we've just
> +         * finished the node before the root(s); set p->fts_info to FTS_INIT
> +         * so that everything about the "current" node is ignored.
> +         */
> +        if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
> +                goto mem3;
> +        sp->fts_cur->fts_link = root;
> +        sp->fts_cur->fts_info = FTS_INIT;
> +        sp->fts_cur->fts_level = 1;
> +        if (! setup_dir (sp))
> +                goto mem3;
> +
> +        /*
> +         * If using chdir(2), grab a file descriptor pointing to dot to ensure
> +         * that we can get back here; this could be avoided for some file names,
> +         * but almost certainly not worth the effort.  Slashes, symbolic links,
> +         * and ".." are all fairly nasty problems.  Note, if we can't get the
> +         * descriptor we run anyway, just more slowly.
> +         */
> +        if (!ISSET(FTS_NOCHDIR) && !ISSET(FTS_CWDFD)
> +            && (sp->fts_rfd = diropen (sp, ".")) < 0)
> +                SET(FTS_NOCHDIR);
> +
> +        i_ring_init (&sp->fts_fd_ring, -1);
> +        return (sp);
> +
> +mem3:   fts_lfree(root);
> +        free(FTSENT_WRAPPER(parent));
> +mem2:   free(sp->fts_path);
> +mem1:   free(sp);
> +        return (NULL);
> +}
> +
> +static void
> +internal_function
> +fts_load (FTSOBJ *sp, register FTSENTRY *p)
> +{
> +        /*
> +         * Load the stream structure for the next traversal.  Since we don't
> +         * actually enter the directory until after the preorder visit, set
> +         * the fts_accpath field specially so the chdir gets done to the right
> +         * place and the user can access the first node.  From fts_open it's
> +         * known that the file name will fit.
> +         */
> +        register size_t len = p->fts_pathlen = p->fts_namelen;
> +        memmove(sp->fts_path, p->fts_name, len + 1);
> +        register char *cp = strrchr(p->fts_name, '/');
> +        if (cp && (cp != p->fts_name || cp[1])) {
> +                len = strlen(++cp);
> +                memmove(p->fts_name, cp, len + 1);
> +                p->fts_namelen = len;
> +        }
> +        p->fts_accpath = p->fts_path = sp->fts_path;
> +}
> +
> +int
> +FTS_CLOSE (FTSOBJ *sp)
> +{
> +        /*
> +         * This still works if we haven't read anything -- the dummy structure
> +         * points to the root list, so we step through to the end of the root
> +         * list which has a valid parent pointer.
> +         */
> +        if (sp->fts_cur) {
> +                register FTSENTRY *p;
> +                for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
> +                        register FTSENTRY *freep = p;
> +                        p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
> +                        free(FTSENT_WRAPPER(freep));
> +                }
> +                free(FTSENT_WRAPPER(p));
> +        }
> +
> +        /* Free up child linked list, sort array, file name buffer. */
> +        if (sp->fts_child)
> +                fts_lfree(sp->fts_child);
> +        free(sp->fts_array);
> +        free(sp->fts_path);
> +
> +        int saved_errno = 0;
> +        if (ISSET(FTS_CWDFD))
> +          {
> +            if (0 <= sp->fts_cwd_fd)
> +              if (close (sp->fts_cwd_fd))
> +                saved_errno = errno;
> +          }
> +        else if (!ISSET(FTS_NOCHDIR))
> +          {
> +            /* Return to original directory, save errno if necessary. */
> +            if (fchdir(sp->fts_rfd))
> +              saved_errno = errno;
> +
> +            /* If close fails, record errno only if saved_errno is zero,
> +               so that we report the probably-more-meaningful fchdir errno.  */
> +            if (close (sp->fts_rfd))
> +              if (saved_errno == 0)
> +                saved_errno = errno;
> +          }
> +
> +        fd_ring_clear (&sp->fts_fd_ring);
> +
> +        if (sp->fts_leaf_optimization_works_ht)
> +          hash_free (sp->fts_leaf_optimization_works_ht);
> +
> +        free_dir (sp);
> +
> +        /* Free up the stream pointer. */
> +        free(sp);
> +
> +        /* Set errno and return. */
> +        if (saved_errno) {
> +                __set_errno (saved_errno);
> +                return (-1);
> +        }
> +
> +        return (0);
> +}
> +
> +/* Minimum link count of a traditional Unix directory.  When leaf
> +   optimization is OK and a directory's st_nlink == MIN_DIR_NLINK,
> +   then the directory has no subdirectories.  */
> +enum { MIN_DIR_NLINK = 2 };
> +
> +/* Whether leaf optimization is OK for a directory.  */
> +enum leaf_optimization
> +  {
> +    /* st_nlink is not reliable for this directory's subdirectories.  */
> +    NO_LEAF_OPTIMIZATION,
> +
> +    /* st_nlink == 2 means the directory lacks subdirectories.  */
> +    OK_LEAF_OPTIMIZATION
> +  };
> +
> +#if (defined __linux__ || defined __ANDROID__) \
> +  && HAVE_SYS_VFS_H && HAVE_FSTATFS && HAVE_STRUCT_STATFS_F_TYPE
> +
> +# include <sys/vfs.h>
> +
> +/* Linux-specific constants from coreutils' src/fs.h */
> +# define S_MAGIC_AFS 0x5346414F
> +# define S_MAGIC_CIFS 0xFF534D42
> +# define S_MAGIC_LUSTRE 0x0BD00BD0
> +# define S_MAGIC_NFS 0x6969
> +# define S_MAGIC_PROC 0x9FA0
> +# define S_MAGIC_TMPFS 0x1021994
> +
> +# ifdef HAVE___FSWORD_T
> +typedef __fsword_t fsword;
> +# else
> +typedef long int fsword;
> +# endif
> +
> +/* Map a stat.st_dev number to a file system type number f_ftype.  */
> +struct dev_type
> +{
> +  dev_t st_dev;
> +  fsword f_type;
> +};
> +
> +/* Use a tiny initial size.  If a traversal encounters more than
> +   a few devices, the cost of growing/rehashing this table will be
> +   rendered negligible by the number of inodes processed.  */
> +enum { DEV_TYPE_HT_INITIAL_SIZE = 13 };
> +
> +static size_t
> +dev_type_hash (void const *x, size_t table_size)
> +{
> +  struct dev_type const *ax = x;
> +  uintmax_t dev = ax->st_dev;
> +  return dev % table_size;
> +}
> +
> +static bool
> +dev_type_compare (void const *x, void const *y)
> +{
> +  struct dev_type const *ax = x;
> +  struct dev_type const *ay = y;
> +  return ax->st_dev == ay->st_dev;
> +}
> +
> +/* Return the file system type of P with file descriptor FD, or 0 if not known.
> +   If FD is negative, P's file descriptor is unavailable.
> +   Try to cache known values.  */
> +
> +static fsword
> +filesystem_type (FTSENTRY const *p, int fd)
> +{
> +  FTSOBJ *sp = FTSENT_FTS(p);
> +
> +  /* If we're not in CWDFD mode, don't bother with this optimization,
> +     since the caller is not serious about performance.  */
> +  if (!ISSET (FTS_CWDFD))
> +    return 0;
> +
> +  Hash_table *h = sp->fts_leaf_optimization_works_ht;
> +  if (! h)
> +    h = sp->fts_leaf_optimization_works_ht
> +      = hash_initialize (DEV_TYPE_HT_INITIAL_SIZE, NULL, dev_type_hash,
> +                         dev_type_compare, free);
> +
> +  if (h)
> +    {
> +      struct dev_type tmp;
> +      tmp.st_dev = p->fts_statp->st_dev;
> +      struct dev_type *ent = hash_lookup (h, &tmp);
> +      if (ent)
> +        return ent->f_type;
> +    }
> +
> +  /* Look-up failed.  Query directly and cache the result.  */
> +  struct STRUCT_STATFS fs_buf;
> +  if (fd < 0 || FSTATFS (fd, &fs_buf) != 0)
> +    return 0;
> +
> +  if (h)
> +    {
> +      struct dev_type *t2 = malloc (sizeof *t2);
> +      if (t2)
> +        {
> +          t2->st_dev = p->fts_statp->st_dev;
> +          t2->f_type = fs_buf.f_type;
> +
> +          struct dev_type *ent = hash_insert (h, t2);
> +          if (ent)
> +            fts_assert (ent == t2);
> +          else
> +            free (t2);
> +        }
> +    }
> +
> +  return fs_buf.f_type;
> +}
> +
> +/* Return true if sorting dirents on inode numbers is known to improve
> +   traversal performance for the directory P with descriptor DIR_FD.
> +   Return false otherwise.  When in doubt, return true.
> +   DIR_FD is negative if unavailable.  */
> +static bool
> +dirent_inode_sort_may_be_useful (FTSENTRY const *p, int dir_fd)
> +{
> +  /* Skip the sort only if we can determine efficiently
> +     that skipping it is the right thing to do.
> +     The cost of performing an unnecessary sort is negligible,
> +     while the cost of *not* performing it can be O(N^2) with
> +     a very large constant.  */
> +
> +  switch (filesystem_type (p, dir_fd))
> +    {
> +    case S_MAGIC_LUSTRE:
> +      /* On Lustre, sorting directory entries interferes with its ability to
> +         prefetch file metadata (via statahead).  This would make a command
> +         like 'du' around 9 times slower.  See
> +         <https://bugs.gnu.org/80106>.  */
> +    case S_MAGIC_CIFS:
> +    case S_MAGIC_NFS:
> +    case S_MAGIC_TMPFS:
> +      /* On a file system of any of these types, sorting
> +         is unnecessary, and hence wasteful.  */
> +      return false;
> +
> +    default:
> +      return true;
> +    }
> +}
> +
> +/* Given an FTS entry P for a directory with descriptor DIR_FD,
> +   return whether it is valid to apply leaf optimization.
> +   The optimization is valid if a directory's st_nlink value equal
> +   to MIN_DIR_NLINK means the directory has no subdirectories.
> +   DIR_FD is negative if unavailable.  */
> +static enum leaf_optimization
> +leaf_optimization (FTSENTRY const *p, int dir_fd)
> +{
> +  switch (filesystem_type (p, dir_fd))
> +    {
> +    case 0:
> +      /* Leaf optimization is unsafe if the file system type is unknown.  */
> +      FALLTHROUGH;
> +    case S_MAGIC_AFS:
> +      /* Although AFS mount points are not counted in st_nlink, they
> +         act like directories.  See <https://bugs.debian.org/143111>.  */
> +      FALLTHROUGH;
> +    case S_MAGIC_CIFS:
> +      /* Leaf optimization causes 'find' to abort.  See
> +         <https://lists.gnu.org/r/bug-gnulib/2018-04/msg00015.html>.  */
> +      FALLTHROUGH;
> +    case S_MAGIC_NFS:
> +      /* NFS provides usable dirent.d_type but not necessarily for all entries
> +         of large directories, so as per <https://bugzilla.redhat.com/1252549>
> +         NFS should return true.  However st_nlink values are not accurate on
> +         all implementations as per <https://bugzilla.redhat.com/1299169>.  */
> +      FALLTHROUGH;
> +    case S_MAGIC_PROC:
> +      /* Per <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=143111> /proc
> +         may have bogus stat.st_nlink values.  */
> +      return NO_LEAF_OPTIMIZATION;
> +
> +    default:
> +      return OK_LEAF_OPTIMIZATION;
> +    }
> +}
> +
> +#else
> +static bool
> +dirent_inode_sort_may_be_useful (_GL_UNUSED FTSENTRY const *p,
> +                                 _GL_UNUSED int dir_fd)
> +{
> +  return true;
> +}
> +static enum leaf_optimization
> +leaf_optimization (_GL_UNUSED FTSENTRY const *p, _GL_UNUSED int dir_fd)
> +{
> +  return NO_LEAF_OPTIMIZATION;
> +}
> +#endif
> +
> +/*
> + * Special case of "/" at the end of the file name so that slashes aren't
> + * appended which would cause file names to be written as "....//foo".
> + */
> +#define NAPPEND(p)                                                      \
> +        (p->fts_path[p->fts_pathlen - 1] == '/'                         \
> +            ? p->fts_pathlen - 1 : p->fts_pathlen)
> +
> +FTSENTRY *
> +FTS_READ (FTSOBJ *sp)
> +{
> +        /* If finished or unrecoverable error, return NULL. */
> +        if (sp->fts_cur == NULL || ISSET(FTS_STOP))
> +                return (NULL);
> +
> +        /* Set current node pointer. */
> +        register FTSENTRY *p = sp->fts_cur;
> +
> +        /* Save and zero out user instructions. */
> +        register unsigned short int instr = p->fts_instr;
> +        p->fts_instr = FTS_NOINSTR;
> +
> +        /* Any type of file may be re-visited; re-stat and re-turn. */
> +        if (instr == FTS_AGAIN) {
> +                p->fts_info = fts_stat(sp, p, false);
> +                return (p);
> +        }
> +        Dprintf (("fts_read: p=%s\n",
> +                  p->fts_info == FTS_INIT ? "" : p->fts_path));
> +
> +        /*
> +         * Following a symlink -- SLNONE test allows application to see
> +         * SLNONE and recover.  If indirecting through a symlink, have
> +         * keep a pointer to current location.  If unable to get that
> +         * pointer, follow fails.
> +         */
> +        if (instr == FTS_FOLLOW &&
> +            (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
> +                p->fts_info = fts_stat(sp, p, true);
> +                if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
> +                        if ((p->fts_symfd = diropen (sp, ".")) < 0) {
> +                                p->fts_errno = errno;
> +                                p->fts_info = FTS_ERR;
> +                        } else
> +                                p->fts_flags |= FTS_SYMFOLLOW;
> +                }
> +                goto check_for_dir;
> +        }
> +
> +        /* Directory in pre-order. */
> +        if (p->fts_info == FTS_D) {
> +                /* If skipped or crossed mount point, do post-order visit. */
> +                if (instr == FTS_SKIP ||
> +                    (ISSET(FTS_XDEV) && p->fts_statp->st_dev != sp->fts_dev)) {
> +                        if (p->fts_flags & FTS_SYMFOLLOW)
> +                                (void)close(p->fts_symfd);
> +                        if (sp->fts_child) {
> +                                fts_lfree(sp->fts_child);
> +                                sp->fts_child = NULL;
> +                        }
> +                        p->fts_info = FTS_DP;
> +                        LEAVE_DIR (sp, p, "1");
> +                        return (p);
> +                }
> +
> +                /* Rebuild if only read the names and now traversing. */
> +                if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) {
> +                        CLR(FTS_NAMEONLY);
> +                        fts_lfree(sp->fts_child);
> +                        sp->fts_child = NULL;
> +                }
> +
> +                /*
> +                 * Cd to the subdirectory.
> +                 *
> +                 * If have already read and now fail to chdir, whack the list
> +                 * to make the names come out right, and set the parent errno
> +                 * so the application will eventually get an error condition.
> +                 * Set the FTS_DONTCHDIR flag so that when we logically change
> +                 * directories back to the parent we don't do a chdir.
> +                 *
> +                 * If haven't read do so.  If the read fails, fts_build sets
> +                 * FTS_STOP or the fts_info field of the node.
> +                 */
> +                if (sp->fts_child != NULL) {
> +                        if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
> +                                p->fts_errno = errno;
> +                                p->fts_flags |= FTS_DONTCHDIR;
> +                                for (p = sp->fts_child; p != NULL;
> +                                     p = p->fts_link)
> +                                        p->fts_accpath =
> +                                            p->fts_parent->fts_accpath;
> +                        }
> +                } else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
> +                        if (ISSET(FTS_STOP))
> +                                return (NULL);
> +                        /* If fts_build's call to fts_safe_changedir failed
> +                           because it was not able to fchdir into a
> +                           subdirectory, tell the caller.  */
> +                        if (p->fts_errno && p->fts_info != FTS_DNR)
> +                                p->fts_info = FTS_ERR;
> +                        LEAVE_DIR (sp, p, "2");
> +                        return (p);
> +                }
> +                p = sp->fts_child;
> +                sp->fts_child = NULL;
> +                goto name;
> +        }
> +
> +        /* Move to the next node on this level. */
> +next: ;
> +        register FTSENTRY *tmp = p;
> +
> +        /* If we have so many directory entries that we're reading them
> +           in batches, and we've reached the end of the current batch,
> +           read in a new batch.  */
> +        if (p->fts_link == NULL && FTSENT_DIRP(p->fts_parent))
> +          {
> +            p = tmp->fts_parent;
> +            sp->fts_cur = p;
> +            sp->fts_path[p->fts_pathlen] = '\0';
> +
> +            if ((p = fts_build (sp, BREAD)) == NULL)
> +              {
> +                if (ISSET(FTS_STOP))
> +                  return NULL;
> +                goto cd_dot_dot;
> +              }
> +
> +            free(FTSENT_WRAPPER(tmp));
> +            goto name;
> +          }
> +
> +        if ((p = p->fts_link) != NULL) {
> +                sp->fts_cur = p;
> +                free(FTSENT_WRAPPER(tmp));
> +
> +                /*
> +                 * If reached the top, return to the original directory (or
> +                 * the root of the tree), and load the file names for the next
> +                 * root.
> +                 */
> +                if (p->fts_level == FTS_ROOTLEVEL) {
> +                        if (restore_initial_cwd(sp)) {
> +                                SET(FTS_STOP);
> +                                return (NULL);
> +                        }
> +                        free_dir(sp);
> +                        fts_load(sp, p);
> +                        if (! setup_dir(sp)) {
> +                                free_dir(sp);
> +                                return (NULL);
> +                        }
> +                        goto check_for_dir;
> +                }
> +
> +                /*
> +                 * User may have called fts_set on the node.  If skipped,
> +                 * ignore.  If followed, get a file descriptor so we can
> +                 * get back if necessary.
> +                 */
> +                if (p->fts_instr == FTS_SKIP)
> +                        goto next;
> +                if (p->fts_instr == FTS_FOLLOW) {
> +                        p->fts_info = fts_stat(sp, p, true);
> +                        if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
> +                                if ((p->fts_symfd = diropen (sp, ".")) < 0) {
> +                                        p->fts_errno = errno;
> +                                        p->fts_info = FTS_ERR;
> +                                } else
> +                                        p->fts_flags |= FTS_SYMFOLLOW;
> +                        }
> +                        p->fts_instr = FTS_NOINSTR;
> +                }
> +
> +name:           {
> +                  register char *t = sp->fts_path + NAPPEND(p->fts_parent);
> +                  *t++ = '/';
> +                  memmove(t, p->fts_name, p->fts_namelen + 1);
> +                }
> +check_for_dir:
> +                sp->fts_cur = p;
> +                if (p->fts_info == FTS_NSOK)
> +                  {
> +                    if (p->fts_statp->st_size == FTS_STAT_REQUIRED)
> +                      p->fts_info = fts_stat(sp, p, false);
> +                    else
> +                      fts_assert (p->fts_statp->st_size == FTS_NO_STAT_REQUIRED);
> +                  }
> +
> +                /* Skip files with different device numbers when FTS_MOUNT
> +                   is set.  */
> +                if (ISSET (FTS_MOUNT) && p->fts_info != FTS_NS &&
> +                    p->fts_level != FTS_ROOTLEVEL &&
> +                    p->fts_statp->st_dev != sp->fts_dev)
> +                      goto next;
> +
> +                if (p->fts_info == FTS_D)
> +                  {
> +                    /* Now that P->fts_statp is guaranteed to be valid, if
> +                       this is a command-line directory, record its device
> +                       number, to be used for FTS_MOUNT and FTS_XDEV.  */
> +                    if (p->fts_level == FTS_ROOTLEVEL)
> +                      sp->fts_dev = p->fts_statp->st_dev;
> +                    Dprintf (("  entering: %s\n", p->fts_path));
> +                    if (! enter_dir (sp, p))
> +                      return NULL;
> +                  }
> +                return p;
> +        }
> +cd_dot_dot:
> +
> +        /* Move up to the parent node. */
> +        p = tmp->fts_parent;
> +        sp->fts_cur = p;
> +        free(FTSENT_WRAPPER(tmp));
> +
> +        if (p->fts_level == FTS_ROOTPARENTLEVEL) {
> +                /*
> +                 * Done; free everything up and set errno to 0 so the user
> +                 * can distinguish between error and EOF.
> +                 */
> +                free(FTSENT_WRAPPER(p));
> +                __set_errno (0);
> +                return (sp->fts_cur = NULL);
> +        }
> +
> +        fts_assert (p->fts_info != FTS_NSOK);
> +
> +        /* NUL terminate the file name.  */
> +        sp->fts_path[p->fts_pathlen] = '\0';
> +
> +        /*
> +         * Return to the parent directory.  If at a root node, restore
> +         * the initial working directory.  If we came through a symlink,
> +         * go back through the file descriptor.  Otherwise, move up
> +         * one level, via "..".
> +         */
> +        if (p->fts_level == FTS_ROOTLEVEL) {
> +                if (restore_initial_cwd(sp)) {
> +                        p->fts_errno = errno;
> +                        SET(FTS_STOP);
> +                }
> +        } else if (p->fts_flags & FTS_SYMFOLLOW) {
> +                if (FCHDIR(sp, p->fts_symfd)) {
> +                        p->fts_errno = errno;
> +                        SET(FTS_STOP);
> +                }
> +                (void)close(p->fts_symfd);
> +        } else if (!(p->fts_flags & FTS_DONTCHDIR) &&
> +                   fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
> +                p->fts_errno = errno;
> +                SET(FTS_STOP);
> +        }
> +
> +        /* If the directory causes a cycle, preserve the FTS_DC flag and keep
> +           the corresponding dev/ino pair in the hash table.  It is going to be
> +           removed when leaving the original directory.  */
> +        if (p->fts_info != FTS_DC) {
> +                p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
> +                if (p->fts_errno == 0)
> +                        LEAVE_DIR (sp, p, "3");
> +        }
> +        return ISSET(FTS_STOP) ? NULL : p;
> +}
> +
> +/*
> + * Fts_set takes the stream as an argument although it's not used in this
> + * implementation; it would be necessary if anyone wanted to add global
> + * semantics to fts using fts_set.  An error return is allowed for similar
> + * reasons.
> + */
> +/* ARGSUSED */
> +int
> +FTS_SET (_GL_UNUSED FTSOBJ *sp, FTSENTRY *p, int instr)
> +{
> +        if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
> +            instr != FTS_NOINSTR && instr != FTS_SKIP) {
> +                __set_errno (EINVAL);
> +                return (1);
> +        }
> +        p->fts_instr = instr;
> +        return (0);
> +}
> +
> +FTSENTRY *
> +FTS_CHILDREN (FTSOBJ *sp, int instr)
> +{
> +        if (instr != 0 && instr != FTS_NAMEONLY) {
> +                __set_errno (EINVAL);
> +                return (NULL);
> +        }
> +
> +        /* Set current node pointer. */
> +        register FTSENTRY *p = sp->fts_cur;
> +
> +        /*
> +         * Errno set to 0 so user can distinguish empty directory from
> +         * an error.
> +         */
> +        __set_errno (0);
> +
> +        /* Fatal errors stop here. */
> +        if (ISSET(FTS_STOP))
> +                return (NULL);
> +
> +        /* Return logical hierarchy of user's arguments. */
> +        if (p->fts_info == FTS_INIT)
> +                return (p->fts_link);
> +
> +        /*
> +         * If not a directory being visited in pre-order, stop here.  Could
> +         * allow FTS_DNR, assuming the user has fixed the problem, but the
> +         * same effect is available with FTS_AGAIN.
> +         */
> +        if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
> +                return (NULL);
> +
> +        /* Free up any previous child list. */
> +        if (sp->fts_child != NULL)
> +                fts_lfree(sp->fts_child);
> +
> +        if (instr == FTS_NAMEONLY) {
> +                SET(FTS_NAMEONLY);
> +                instr = BNAMES;
> +        } else
> +                instr = BCHILD;
> +
> +        /*
> +         * If using chdir on a relative file name and called BEFORE fts_read
> +         * does its chdir to the root of a traversal, we can lose -- we need to
> +         * chdir into the subdirectory, and we don't know where the current
> +         * directory is, so we can't get back so that the upcoming chdir by
> +         * fts_read will work.
> +         */
> +        if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
> +            ISSET(FTS_NOCHDIR))
> +                return (sp->fts_child = fts_build(sp, instr));
> +
> +        int fd = diropen (sp, ".");
> +        if (fd < 0)
> +                return (sp->fts_child = NULL);
> +        sp->fts_child = fts_build(sp, instr);
> +        if (ISSET(FTS_CWDFD))
> +          {
> +            cwd_advance_fd (sp, fd, true);
> +          }
> +        else
> +          {
> +            if (fchdir(fd))
> +              {
> +                int saved_errno = errno;
> +                close (fd);
> +                __set_errno (saved_errno);
> +                return NULL;
> +              }
> +            close (fd);
> +          }
> +        return (sp->fts_child);
> +}
> +
> +/* A comparison function to sort on increasing inode number.
> +   For some file system types, sorting either way makes a huge
> +   performance difference for a directory with very many entries,
> +   but sorting on increasing values is slightly better than sorting
> +   on decreasing values.  The difference is in the 5% range.  */
> +static int
> +fts_compare_ino (FTSENTRY const **a, FTSENTRY const **b)
> +{
> +  return _GL_CMP (a[0]->fts_statp->st_ino, b[0]->fts_statp->st_ino);
> +}
> +
> +/* Map the dirent.d_type value, DTYPE, to the corresponding stat.st_mode
> +   S_IF* bit and set ST.st_mode, thus clearing all other bits in that field.  */
> +static void
> +set_stat_type (struct STRUCT_STAT *st, unsigned int dtype)
> +{
> +  mode_t type;
> +  switch (dtype)
> +    {
> +    case DT_BLK:
> +      type = S_IFBLK;
> +      break;
> +    case DT_CHR:
> +      type = S_IFCHR;
> +      break;
> +    case DT_DIR:
> +      type = S_IFDIR;
> +      break;
> +    case DT_FIFO:
> +      type = S_IFIFO;
> +      break;
> +    case DT_LNK:
> +      type = S_IFLNK;
> +      break;
> +    case DT_REG:
> +      type = S_IFREG;
> +      break;
> +    case DT_SOCK:
> +      type = S_IFSOCK;
> +      break;
> +    default:
> +      type = 0;
> +    }
> +  st->st_mode = type;
> +}
> +
> +#define closedir_and_clear(dirp)                \
> +  do                                            \
> +    {                                           \
> +      closedir (dirp);                          \
> +      dirp = NULL;                              \
> +    }                                           \
> +  while (0)
> +
> +#define fts_opendir(file, Pdir_fd)                              \
> +        OPENDIRAT((! ISSET(FTS_NOCHDIR) && ISSET(FTS_CWDFD)     \
> +                   ? sp->fts_cwd_fd : AT_FDCWD),                \
> +                  file,                                         \
> +                  (((ISSET(FTS_PHYSICAL)                        \
> +                     && ! (ISSET(FTS_COMFOLLOW)                 \
> +                           && cur->fts_level == FTS_ROOTLEVEL)) \
> +                    ? O_NOFOLLOW : 0)),                         \
> +                  Pdir_fd)
> +
> +/*
> + * This is the tricky part -- do not casually change *anything* in here.  The
> + * idea is to build the linked list of entries that are used by fts_children
> + * and fts_read.  There are lots of special cases.
> + *
> + * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
> + * set and it's a physical walk (so that symbolic links can't be directories),
> + * we can do things quickly.  First, if it's a 4.4BSD file system, the type
> + * of the file is in the directory entry.  Otherwise, we assume that the number
> + * of subdirectories in a node is equal to the number of links to the parent.
> + * The former skips all stat calls.  The latter skips stat calls in any leaf
> + * directories and for any files after the subdirectories in the directory have
> + * been found, cutting the stat calls by about 2/3.
> + */
> +static FTSENTRY *
> +internal_function
> +fts_build (register FTSOBJ *sp, int type)
> +{
> +        FTSENTRY *cur = sp->fts_cur;
> +        bool continue_readdir = !!FTSENT_DIRP(cur);
> +
> +        /* When cur->fts_dirp is non-NULL, that means we should
> +           continue calling readdir on that existing DIR* pointer
> +           rather than opening a new one.  */
> +        int dir_fd;
> +        if (continue_readdir)
> +          {
> +            DIR *dp = FTSENT_DIRP(cur);
> +            dir_fd = dirfd (dp);
> +            if (dir_fd < 0)
> +              {
> +                int dirfd_errno = errno;
> +                closedir_and_clear (FTSENT_DIRP(cur));
> +                if (type == BREAD)
> +                  {
> +                    cur->fts_info = FTS_DNR;
> +                    cur->fts_errno = dirfd_errno;
> +                  }
> +                return NULL;
> +              }
> +          }
> +        else
> +          {
> +            /* Open the directory for reading.  If this fails, we're done.
> +               If being called from fts_read, set the fts_info field. */
> +            if ((FTSENT_DIRP (cur) = fts_opendir(cur->fts_accpath, &dir_fd)) == NULL)
> +              {
> +                if (type == BREAD)
> +                  {
> +                    cur->fts_info = FTS_DNR;
> +                    cur->fts_errno = errno;
> +                  }
> +                return NULL;
> +              }
> +            /* Rather than calling fts_stat for each and every entry encountered
> +               in the readdir loop (below), stat each directory only right after
> +               opening it.  */
> +            bool stat_optimization = cur->fts_info == FTS_NSOK;
> +
> +            if (stat_optimization
> +                /* Also read the stat info again after opening a directory to
> +                   reveal eventual changes caused by a submount triggered by
> +                   the traversal.  But do it only for utilities which use
> +                   FTS_TIGHT_CYCLE_CHECK.  Therefore, only find and du
> +                   benefit/suffer from this feature for now.  */
> +                || ISSET (FTS_TIGHT_CYCLE_CHECK))
> +              {
> +                if (!stat_optimization)
> +                  LEAVE_DIR (sp, cur, "4");
> +                if (FSTAT (dir_fd, cur->fts_statp) != 0)
> +                  {
> +                    int fstat_errno = errno;
> +                    closedir_and_clear (FTSENT_DIRP(cur));
> +                    if (type == BREAD)
> +                      {
> +                        cur->fts_errno = fstat_errno;
> +                        cur->fts_info = FTS_NS;
> +                      }
> +                    __set_errno (fstat_errno);
> +                    return NULL;
> +                  }
> +                if (stat_optimization)
> +                  cur->fts_info = FTS_D;
> +                else if (! enter_dir (sp, cur))
> +                  {
> +                    int saved_errno = errno;
> +                    closedir_and_clear (FTSENT_DIRP(cur));
> +                    __set_errno (saved_errno);
> +                    return NULL;
> +                  }
> +              }
> +          }
> +
> +        /* Maximum number of readdir entries to read at one time.  This
> +           limitation is to avoid reading millions of entries into memory
> +           at once.  When an fts_compar function is specified, we have no
> +           choice: we must read all entries into memory before calling that
> +           function.  But when no such function is specified, we can read
> +           entries in batches that are large enough to help us with inode-
> +           sorting, yet not so large that we risk exhausting memory.  */
> +        size_t max_entries = sp->fts_compar ? SIZE_MAX : FTS_MAX_READDIR_ENTRIES;
> +
> +        /*
> +         * If we're going to need to stat anything or we want to descend
> +         * and stay in the directory, chdir.  If this fails we keep going,
> +         * but set a flag so we don't chdir after the post-order visit.
> +         * We won't be able to stat anything, but we can still return the
> +         * names themselves.  Note, that since fts_read won't be able to
> +         * chdir into the directory, it will have to return different file
> +         * names than before, i.e. "a/b" instead of "b".  Since the node
> +         * has already been visited in pre-order, have to wait until the
> +         * post-order visit to return the error.  There is a special case
> +         * here, if there was nothing to stat then it's not an error to
> +         * not be able to stat.  This is all fairly nasty.  If a program
> +         * needed sorted entries or stat information, they had better be
> +         * checking FTS_NS on the returned nodes.
> +         */
> +        bool descend;
> +        if (continue_readdir)
> +          {
> +            /* When resuming a short readdir run, we already have
> +               the required dirp and dir_fd.  */
> +            descend = true;
> +          }
> +        else
> +          {
> +            /* Try to descend unless it is a names-only fts_children,
> +               or the directory is known to lack subdirectories.  */
> +            descend = (type != BNAMES
> +                       && ! (ISSET (FTS_NOSTAT) && ISSET (FTS_PHYSICAL)
> +                             && ! ISSET (FTS_SEEDOT)
> +                             && cur->fts_statp->st_nlink == MIN_DIR_NLINK
> +                             && (leaf_optimization (cur, dir_fd)
> +                                 != NO_LEAF_OPTIMIZATION)));
> +            if (descend || type == BREAD)
> +              {
> +                if (ISSET(FTS_CWDFD))
> +                  dir_fd = fcntl (dir_fd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1);
> +                if (dir_fd < 0 || fts_safe_changedir(sp, cur, dir_fd, NULL)) {
> +                        if (descend && type == BREAD)
> +                                cur->fts_errno = errno;
> +                        cur->fts_flags |= FTS_DONTCHDIR;
> +                        descend = false;
> +                        closedir_and_clear(FTSENT_DIRP(cur));
> +                        if (ISSET(FTS_CWDFD) && 0 <= dir_fd)
> +                                close (dir_fd);
> +                        FTSENT_DIRP(cur) = NULL;
> +                } else
> +                        descend = true;
> +              }
> +          }
> +
> +        /*
> +         * Figure out the max file name length that can be stored in the
> +         * current buffer -- the inner loop allocates more space as necessary.
> +         * We really wouldn't have to do the maxlen calculations here, we
> +         * could do them in fts_read before returning the name, but it's a
> +         * lot easier here since the length is part of the dirent structure.
> +         *
> +         * If not changing directories set a pointer so that can just append
> +         * each new component into the file name.
> +         */
> +        size_t len = NAPPEND(cur);
> +        char *cp;
> +        if (ISSET(FTS_NOCHDIR)) {
> +                cp = sp->fts_path + len;
> +                *cp++ = '/';
> +        } else {
> +                /* GCC, you're too verbose. */
> +                cp = NULL;
> +        }
> +        len++;
> +        size_t maxlen = sp->fts_pathlen - len;
> +
> +        ptrdiff_t level = cur->fts_level + 1;
> +
> +        /* Read the directory, attaching each entry to the "link" pointer. */
> +        bool doadjust = false;
> +        register FTSENTRY *head = NULL;
> +        FTSENTRY *tail = NULL;
> +        register size_t nitems = 0;
> +        bool sort_by_inode = false;
> +        while (FTSENT_DIRP(cur)) {
> +                __set_errno (0);
> +                struct dirent *dp = readdir(FTSENT_DIRP(cur));
> +                if (dp == NULL) {
> +                        /* Some readdir()s do not absorb ENOENT (dir
> +                           deleted but open).  This bug was fixed in
> +                           glibc 2.3 (2002).  */
> +#if ! (2 < __GLIBC__ + (3 <= __GLIBC_MINOR__))
> +                        if (errno == ENOENT)
> +                          errno = 0;
> +#endif
> +                        if (errno) {
> +                                cur->fts_errno = errno;
> +                                /* If we've not read any items yet, treat
> +                                   the error as if we can't access the dir.  */
> +                                cur->fts_info = (continue_readdir || nitems)
> +                                                ? FTS_ERR : FTS_DNR;
> +                        }
> +                        closedir_and_clear(FTSENT_DIRP(cur));
> +                        break;
> +                }
> +                if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
> +                        continue;
> +
> +                size_t d_namelen = _D_EXACT_NAMLEN (dp);
> +                register FTSENTRY *p = fts_alloc (sp, dp->d_name, d_namelen);
> +                if (!p)
> +                        goto mem1;
> +                if (d_namelen >= maxlen) {
> +                        /* include space for NUL */
> +                        uintptr_t oldaddr = (uintptr_t) sp->fts_path;
> +                        if (! fts_palloc(sp, d_namelen + len + 1)) {
> +                                /*
> +                                 * No more memory.  Save
> +                                 * errno, free up the current structure and the
> +                                 * structures already allocated.
> +                                 */
> +mem1: ;
> +                                int saved_errno = errno;
> +                                free(FTSENT_WRAPPER(p));
> +                                fts_lfree(head);
> +                                closedir_and_clear(FTSENT_DIRP(cur));
> +                                cur->fts_info = FTS_ERR;
> +                                SET(FTS_STOP);
> +                                __set_errno (saved_errno);
> +                                return (NULL);
> +                        }
> +                        /* Did realloc() change the pointer? */
> +                        if (oldaddr != (uintptr_t) sp->fts_path) {
> +                                doadjust = true;
> +                                if (ISSET(FTS_NOCHDIR))
> +                                        cp = sp->fts_path + len;
> +                        }
> +                        maxlen = sp->fts_pathlen - len;
> +                }
> +
> +                size_t new_len = len + d_namelen;
> +                if (new_len < len) {
> +                        /*
> +                         * In the unlikely event that we would end up
> +                         * with a file name longer than SIZE_MAX, free up
> +                         * the current structure and the structures already
> +                         * allocated, then error out with ENAMETOOLONG.
> +                         */
> +                        free(FTSENT_WRAPPER(p));
> +                        fts_lfree(head);
> +                        closedir_and_clear(FTSENT_DIRP(cur));
> +                        cur->fts_info = FTS_ERR;
> +                        SET(FTS_STOP);
> +                        __set_errno (ENAMETOOLONG);
> +                        return (NULL);
> +                }
> +                p->fts_level = level;
> +                p->fts_parent = sp->fts_cur;
> +                p->fts_pathlen = new_len;
> +
> +                /* Store dirent.d_ino, in case we need to sort
> +                   entries before processing them.  */
> +                p->fts_statp->st_ino = D_INO (dp);
> +
> +                /* Build a file name for fts_stat to stat. */
> +                if (ISSET(FTS_NOCHDIR)) {
> +                        p->fts_accpath = p->fts_path;
> +                        memmove(cp, p->fts_name, p->fts_namelen + 1);
> +                } else
> +                        p->fts_accpath = p->fts_name;
> +
> +                if (sp->fts_compar == NULL || ISSET(FTS_DEFER_STAT)) {
> +                        /* Record what fts_read will have to do with this
> +                           entry. In many cases, it will simply fts_stat it,
> +                           but we can take advantage of any d_type information
> +                           to optimize away the unnecessary stat calls.  I.e.,
> +                           if FTS_NOSTAT is in effect, we don't need device
> +                           numbers unconditionally (FTS_MOUNT) and we're not
> +                           following symlinks (FTS_PHYSICAL) and d_type
> +                           indicates this is *not* a directory, then we won't
> +                           have to stat it  at all.  If it *is* a directory,
> +                           then (currently) we stat it regardless, in order to
> +                           get device and inode numbers.  Some day we might
> +                           optimize that away, too, for directories where
> +                           d_ino is known to be valid.  */
> +                        bool skip_stat = (ISSET(FTS_NOSTAT)
> +                                          && DT_IS_KNOWN(dp)
> +                                          && ! DT_MUST_BE(dp, DT_DIR)
> +                                          && (ISSET(FTS_PHYSICAL)
> +                                              || ! DT_MUST_BE(dp, DT_LNK))
> +                                          && ! ISSET(FTS_MOUNT));
> +                        p->fts_info = FTS_NSOK;
> +                        /* Propagate dirent.d_type information back
> +                           to caller, when possible.  */
> +                        set_stat_type (p->fts_statp, D_TYPE (dp));
> +                        fts_set_stat_required(p, !skip_stat);
> +                } else {
> +                        p->fts_info = fts_stat(sp, p, false);
> +                }
> +
> +                /* We walk in directory order so "ls -f" doesn't get upset. */
> +                p->fts_link = NULL;
> +                if (head == NULL)
> +                        head = tail = p;
> +                else {
> +                        tail->fts_link = p;
> +                        tail = p;
> +                }
> +
> +                /* If there are many entries, no sorting function has been
> +                   specified, and this file system is of a type that may be
> +                   slow with a large number of entries, arrange to sort the
> +                   directory entries on increasing inode numbers.
> +
> +                   The NITEMS comparison uses ==, not >, because the test
> +                   needs to be tried at most once once, and NITEMS will exceed
> +                   the threshold after it is incremented below.  */
> +                if (nitems == _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
> +                    && !sp->fts_compar)
> +                  sort_by_inode = dirent_inode_sort_may_be_useful (cur, dir_fd);
> +
> +                ++nitems;
> +                if (max_entries <= nitems) {
> +                        /* When there are too many dir entries, leave
> +                           fts_dirp open, so that a subsequent fts_read
> +                           can take up where we leave off.  */
> +                        break;
> +                }
> +        }
> +
> +        /*
> +         * If realloc() changed the address of the file name, adjust the
> +         * addresses for the rest of the tree and the dir list.
> +         */
> +        if (doadjust)
> +                fts_padjust(sp, head);
> +
> +        /*
> +         * If not changing directories, reset the file name back to original
> +         * state.
> +         */
> +        if (ISSET(FTS_NOCHDIR)) {
> +                if (len == sp->fts_pathlen || nitems == 0)
> +                        --cp;
> +                *cp = '\0';
> +        }
> +
> +        /*
> +         * If descended after called from fts_children or after called from
> +         * fts_read and nothing found, get back.  At the root level we use
> +         * the saved fd; if one of fts_open()'s arguments is a relative name
> +         * to an empty directory, we wind up here with no other way back.  If
> +         * can't get back, we're done.
> +         */
> +        if (!continue_readdir && descend && (type == BCHILD || !nitems) &&
> +            (cur->fts_level == FTS_ROOTLEVEL
> +             ? restore_initial_cwd(sp)
> +             : fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
> +                cur->fts_info = FTS_ERR;
> +                SET(FTS_STOP);
> +                fts_lfree(head);
> +                return (NULL);
> +        }
> +
> +        /* If didn't find anything, return NULL. */
> +        if (!nitems) {
> +                if (type == BREAD
> +                    && cur->fts_info != FTS_DNR && cur->fts_info != FTS_ERR)
> +                        cur->fts_info = FTS_DP;
> +                fts_lfree(head);
> +                return (NULL);
> +        }
> +
> +        if (sort_by_inode) {
> +                sp->fts_compar = FTS_COMPAR_CAST (fts_compare_ino);
> +                head = fts_sort (sp, head, nitems);
> +                sp->fts_compar = NULL;
> +        }
> +
> +        /* Sort the entries. */
> +        if (sp->fts_compar && nitems > 1)
> +                head = fts_sort(sp, head, nitems);
> +        return (head);
> +}
> +
> +#if GNULIB_FTS_DEBUG
> +
> +struct devino {
> +  intmax_t dev, ino;
> +};
> +#define PRINT_DEVINO "(%jd,%jd)"
> +
> +static struct devino
> +getdevino (int fd)
> +{
> +  struct STRUCT_STAT st;
> +  return (fd == AT_FDCWD
> +          ? (struct devino) { -1, 0 }
> +          : FSTAT (fd, &st) == 0
> +          ? (struct devino) { st.st_dev, st.st_ino }
> +          : (struct devino) { -1, errno });
> +}
> +
> +/* Walk ->fts_parent links starting at E_CURR, until the root of the
> +   current hierarchy.  There should be a directory with dev/inode
> +   matching those of AD.  If not, print a lot of diagnostics.  */
> +static void
> +find_matching_ancestor (FTSENTRY const *e_curr, struct Active_dir const *ad)
> +{
> +  for (FTSENTRY const *ent = e_curr;
> +       ent->fts_level >= FTS_ROOTLEVEL;
> +       ent = ent->fts_parent)
> +    {
> +      if (ad->ino == ent->fts_statp->st_ino
> +          && ad->dev == ent->fts_statp->st_dev)
> +        return;
> +    }
> +  printf ("ERROR: tree dir, %s, not active\n", ad->fts_ent->fts_accpath);
> +  printf ("active dirs:\n");
> +  for (FTSENTRY const *ent = e_curr;
> +       ent->fts_level >= FTS_ROOTLEVEL;
> +       ent = ent->fts_parent)
> +    printf ("  %s(%"PRIuMAX"/%"PRIuMAX") to %s(%"PRIuMAX"/%"PRIuMAX")...\n",
> +            ad->fts_ent->fts_accpath,
> +            (uintmax_t) ad->dev,
> +            (uintmax_t) ad->ino,
> +            ent->fts_accpath,
> +            (uintmax_t) ent->fts_statp->st_dev,
> +            (uintmax_t) ent->fts_statp->st_ino);
> +}
> +
> +void
> +fts_cross_check (FTSOBJ const *sp)
> +{
> +  if ( ! ISSET (FTS_TIGHT_CYCLE_CHECK))
> +    return;
> +
> +  FTSENTRY const *ent = sp->fts_cur;
> +
> +  Dprintf (("fts-cross-check cur=%s\n", ent->fts_path));
> +  /* Make sure every parent dir is in the tree.  */
> +  for (FTSENTRY const *t = ent->fts_parent;
> +       t->fts_level >= FTS_ROOTLEVEL;
> +       t = t->fts_parent)
> +    {
> +      struct Active_dir ad;
> +      ad.ino = t->fts_statp->st_ino;
> +      ad.dev = t->fts_statp->st_dev;
> +      if ( ! hash_lookup (sp->fts_cycle.ht, &ad))
> +        printf ("ERROR: active dir, %s, not in tree\n", t->fts_path);
> +    }
> +
> +  /* Make sure every dir in the tree is an active dir.
> +     But ENT is not necessarily a directory.  If so, just skip this part. */
> +  if (ent->fts_parent->fts_level >= FTS_ROOTLEVEL
> +      && (ent->fts_info == FTS_DP
> +          || ent->fts_info == FTS_D))
> +    for (struct Active_dir *ad = hash_get_first (sp->fts_cycle.ht);
> +         ad != NULL;
> +         ad = hash_get_next (sp->fts_cycle.ht, ad))
> +      {
> +        find_matching_ancestor (ent, ad);
> +      }
> +}
> +
> +static bool
> +same_fd (int fd1, int fd2)
> +{
> +  struct STRUCT_STAT sb1, sb2;
> +  return (FSTAT (fd1, &sb1) == 0
> +          && FSTAT (fd2, &sb2) == 0
> +          && psame_inode (&sb1, &sb2));
> +}
> +
> +static void
> +fd_ring_print (FTSOBJ const *sp, FILE *stream, char const *msg)
> +{
> +  if (!fts_debug)
> +    return;
> +  I_ring const *fd_ring = &sp->fts_fd_ring;
> +  struct devino cwd = getdevino (sp->fts_cwd_fd);
> +  fprintf (stream, "=== %s ========== "PRINT_DEVINO"\n", msg, cwd.dev, cwd.ino);
> +  if (i_ring_empty (fd_ring))
> +    return;
> +
> +  unsigned int i = fd_ring->ir_front;
> +  while (true)
> +    {
> +      int fd = fd_ring->ir_data[i];
> +      if (fd < 0)
> +        fprintf (stream, "%u: %d:\n", i, fd);
> +      else
> +        {
> +          struct devino wd = getdevino (fd);
> +          fprintf (stream, "%u: %d: "PRINT_DEVINO"\n", i, fd, wd.dev, wd.ino);
> +        }
> +      if (i == fd_ring->ir_back)
> +        break;
> +      i = (i + I_RING_SIZE - 1) % I_RING_SIZE;
> +    }
> +}
> +
> +/* Ensure that each file descriptor on the fd_ring matches a
> +   parent, grandparent, etc. of the current working directory.  */
> +static void
> +fd_ring_check (FTSOBJ const *sp)
> +{
> +  if (!fts_debug)
> +    return;
> +
> +  /* Make a writable copy.  */
> +  I_ring fd_w = sp->fts_fd_ring;
> +
> +  int cwd_fd = sp->fts_cwd_fd;
> +  cwd_fd = fcntl (cwd_fd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1);
> +  struct devino dot = getdevino (cwd_fd);
> +  fprintf (stderr, "===== check ===== cwd: "PRINT_DEVINO"\n",
> +           dot.dev, dot.ino);
> +  while ( ! i_ring_empty (&fd_w))
> +    {
> +      int fd = i_ring_pop (&fd_w);
> +      if (0 <= fd)
> +        {
> +          int open_flags = O_SEARCH | O_CLOEXEC;
> +          int parent_fd = openat (cwd_fd, "..", open_flags);
> +          if (parent_fd < 0)
> +            {
> +              // Warn?
> +              break;
> +            }
> +          if (!same_fd (fd, parent_fd))
> +            {
> +              struct devino cwd = getdevino (fd);
> +              fprintf (stderr, "ring  : "PRINT_DEVINO"\n", cwd.dev, cwd.ino);
> +              struct devino c2 = getdevino (parent_fd);
> +              fprintf (stderr, "parent: "PRINT_DEVINO"\n", c2.dev, c2.ino);
> +              fts_assert (0);
> +            }
> +          close (cwd_fd);
> +          cwd_fd = parent_fd;
> +        }
> +    }
> +  close (cwd_fd);
> +}
> +#endif
> +
> +static unsigned short int
> +internal_function
> +fts_stat(FTSOBJ *sp, register FTSENTRY *p, bool follow)
> +{
> +        if (ISSET (FTS_LOGICAL)
> +            || (ISSET (FTS_COMFOLLOW) && p->fts_level == FTS_ROOTLEVEL))
> +                follow = true;
> +
> +        struct STRUCT_STAT *sbp = p->fts_statp;
> +
> +        /*
> +         * If doing a logical walk, or application requested FTS_FOLLOW, do
> +         * a stat(2).  If that fails, check for a nonexistent symlink.  If
> +         * fail, set the errno from the stat call.
> +         */
> +        int flags = follow ? 0 : AT_SYMLINK_NOFOLLOW;
> +        if (FSTATAT (sp->fts_cwd_fd, p->fts_accpath, sbp, flags) < 0)
> +          {
> +            if (follow && errno == ENOENT
> +                && 0 <= FSTATAT (sp->fts_cwd_fd, p->fts_accpath, sbp,
> +                                 AT_SYMLINK_NOFOLLOW))
> +              {
> +                __set_errno (0);
> +                return FTS_SLNONE;
> +              }
> +
> +            p->fts_errno = errno;
> +           memset (sbp, 0, sizeof *sbp);
> +            return FTS_NS;
> +          }
> +
> +        if (S_ISDIR(sbp->st_mode)) {
> +                if (ISDOT(p->fts_name)) {
> +                        /* Command-line "." and ".." are real directories. */
> +                        return (p->fts_level == FTS_ROOTLEVEL ? FTS_D : FTS_DOT);
> +                }
> +
> +                return (FTS_D);
> +        }
> +        if (S_ISLNK(sbp->st_mode))
> +                return (FTS_SL);
> +        if (S_ISREG(sbp->st_mode))
> +                return (FTS_F);
> +        return (FTS_DEFAULT);
> +}
> +
> +static int
> +fts_compar (void const *a, void const *b)
> +{
> +  /* Convert A and B to the correct types, to pacify the compiler, and
> +     for portability to bizarre hosts where "void const *" and "FTSENT
> +     const **" differ in runtime representation.  The comparison
> +     function cannot modify *a and *b, but there is no compile-time
> +     check for this.  */
> +  FTSENTRY const **pa = (FTSENTRY const **) a;
> +  FTSENTRY const **pb = (FTSENTRY const **) b;
> +  return FTSENT_FTS(pa[0])->fts_compar (pa, pb);
> +}
> +
> +static FTSENTRY *
> +internal_function
> +fts_sort (FTSOBJ *sp, FTSENTRY *head, register size_t nitems)
> +{
> +        register FTSENTRY **ap, *p;
> +
> +        /* On most modern hosts, void * and FTSENT ** have the same
> +           run-time representation, and one can convert sp->fts_compar to
> +           the type qsort expects without problem.  Use the heuristic that
> +           this is OK if the two pointer types are the same size, and if
> +           converting FTSENT ** to uintptr_t is the same as converting
> +           FTSENT ** to void * and then to uintptr_t.  This heuristic isn't
> +           valid in general but we don't know of any counterexamples.  */
> +        FTSENTRY *dummy;
> +        int (*compare) (void const *, void const *) =
> +          ((sizeof &dummy == sizeof (void *)
> +            && (uintptr_t) &dummy == (uintptr_t) (void *) &dummy)
> +           ? (int (*) (void const *, void const *)) sp->fts_compar
> +           : fts_compar);
> +
> +        /*
> +         * Construct an array of pointers to the structures and call qsort(3).
> +         * Reassemble the array in the order returned by qsort.  If unable to
> +         * sort for memory reasons, return the directory entries in their
> +         * current order.  Allocate enough space for the current needs plus
> +         * 40 so don't realloc one entry at a time.
> +         */
> +        if (nitems > sp->fts_nitems) {
> +                sp->fts_nitems = nitems + 40;
> +                FTSENTRY **a;
> +                if (! (a = reallocarray (sp->fts_array,
> +                                         sp->fts_nitems, sizeof *a))) {
> +                        free(sp->fts_array);
> +                        sp->fts_array = NULL;
> +                        sp->fts_nitems = 0;
> +                        return (head);
> +                }
> +                sp->fts_array = a;
> +        }
> +        for (ap = sp->fts_array, p = head; p; p = p->fts_link)
> +                *ap++ = p;
> +        qsort((void *)sp->fts_array, nitems, sizeof(FTSENTRY *), compare);
> +        for (head = *(ap = sp->fts_array); --nitems; ++ap)
> +                ap[0]->fts_link = ap[1];
> +        ap[0]->fts_link = NULL;
> +        return (head);
> +}
> +
> +static FTSENTRY *
> +internal_function
> +fts_alloc (FTSOBJ *sp, const char *name, register size_t namelen)
> +{
> +        /*
> +         * The file name is a variable length array.  Allocate the FTSENT
> +         * structure and the file name in one chunk.
> +         */
> +        size_t len = FLEXSIZEOF(FTSENT, fts_name, namelen + 1);
> +	register FTSENTRY *p;
> +#if !_LIBC
> +        p = malloc(len);
> +        if (p == NULL)
> +                return (NULL);
> +#else
> +	/*
> +	 * For glibc, we use a wrapper struct to provide the extra required
> +	 * fields without changing the FSENT layout.
> +	 */
> +	len += sizeof (struct FTSENT_wrapper);
> +	struct FTSENT_wrapper *wrapper = malloc(len);
> +	if (wrapper == NULL)
> +		return (NULL);
> +	p = &wrapper->ent;
> +        p->fts_statp = &wrapper->fts_stat;
> +#endif
> +
> +        /* Copy the name and guarantee NUL termination. */
> +        memcpy(p->fts_name, name, namelen);
> +        p->fts_name[namelen] = '\0';
> +
> +        p->fts_namelen = namelen;
> +        FTSENT_FTS(p)= sp;
> +        p->fts_path = sp->fts_path;
> +        p->fts_errno = 0;
> +        FTSENT_DIRP(p) = NULL;
> +        p->fts_flags = 0;
> +        p->fts_instr = FTS_NOINSTR;
> +        p->fts_number = 0;
> +        p->fts_pointer = NULL;
> +        return (p);
> +}
> +
> +static void
> +internal_function
> +fts_lfree (register FTSENTRY *head)
> +{
> +        int saved_errno = errno;
> +
> +        /* Free a linked list of structures. */
> +        register FTSENTRY *p;
> +        while ((p = head)) {
> +                head = head->fts_link;
> +                if (FTSENT_DIRP(p))
> +                        closedir (FTSENT_DIRP(p));
> +                free(FTSENT_WRAPPER(p));
> +        }
> +
> +        __set_errno (saved_errno);
> +}
> +
> +/*
> + * Allow essentially unlimited file name lengths; find, rm, ls should
> + * all work on any tree.  Most systems will allow creation of file
> + * names much longer than MAXPATHLEN, even though the kernel won't
> + * resolve them.  Add the size (not just what's needed) plus 256 bytes
> + * so don't realloc the file name 2 bytes at a time.
> + */
> +static bool
> +internal_function
> +fts_palloc (FTSOBJ *sp, size_t more)
> +{
> +        size_t new_len = sp->fts_pathlen + more + 256;
> +
> +        /*
> +         * See if fts_pathlen would overflow.
> +         */
> +        if (new_len < sp->fts_pathlen) {
> +                free(sp->fts_path);
> +                sp->fts_path = NULL;
> +                __set_errno (ENAMETOOLONG);
> +                return false;
> +        }
> +        sp->fts_pathlen = new_len;
> +        char *p = realloc(sp->fts_path, sp->fts_pathlen);
> +        if (p == NULL) {
> +                free(sp->fts_path);
> +                sp->fts_path = NULL;
> +                return false;
> +        }
> +        sp->fts_path = p;
> +        return true;
> +}
> +
> +/*
> + * When the file name is realloc'd, have to fix all of the pointers in
> + *  structures already returned.
> + */
> +static void
> +internal_function
> +fts_padjust (FTSOBJ *sp, FTSENTRY *head)
> +{
> +        char *addr = sp->fts_path;
> +
> +        /* This code looks at bit-patterns of freed pointers to
> +           relocate them, so it relies on undefined behavior.  If this
> +           trick does not work on your platform, please report a bug.  */
> +
> +#define ADJUST(p) do {                                                  \
> +        uintptr_t old_accpath = (uintptr_t) (p)->fts_accpath;           \
> +        if (old_accpath != (uintptr_t) (p)->fts_name) {                 \
> +                (p)->fts_accpath =                                      \
> +                  addr + (old_accpath - (uintptr_t) (p)->fts_path);     \
> +        }                                                               \
> +        (p)->fts_path = addr;                                           \
> +} while (0)
> +        /* Adjust the current set of children. */
> +        for (FTSENTRY *p = sp->fts_child; p; p = p->fts_link)
> +                ADJUST(p);
> +
> +        /* Adjust the rest of the tree, including the current level. */
> +        for (FTSENTRY *p = head; p->fts_level >= FTS_ROOTLEVEL;) {
> +                ADJUST(p);
> +                p = p->fts_link ? p->fts_link : p->fts_parent;
> +        }
> +}
> +
> +static size_t
> +internal_function _GL_ATTRIBUTE_PURE
> +fts_maxarglen (char * const *argv)
> +{
> +        size_t max;
> +
> +        for (max = 0; *argv; ++argv) {
> +                size_t len = strlen(*argv);
> +                if (len > max)
> +                        max = len;
> +        }
> +        return (max + 1);
> +}
> +
> +/*
> + * Change to dir specified by fd or file name without getting
> + * tricked by someone changing the world out from underneath us.
> + * Assumes p->fts_statp->st_dev and p->fts_statp->st_ino are filled in.
> + * If FD is non-negative, expect it to be used after this function returns,
> + * and to be closed eventually.  So don't pass e.g., 'dirfd(dirp)' and then
> + * do closedir(dirp), because that would invalidate the saved FD.
> + * Upon failure, close FD immediately and return nonzero.
> + */
> +static int
> +internal_function
> +fts_safe_changedir (FTSOBJ *sp, FTSENTRY *p, int fd, char const *dir)
> +{
> +        fts_assert (0 <= fd || dir != NULL);
> +        bool is_dotdot = dir && streq (dir, "..");
> +
> +        /* This clause handles the unusual case in which FTS_NOCHDIR
> +           is specified, along with FTS_CWDFD.  In that case, there is
> +           no need to change even the virtual cwd file descriptor.
> +           However, if FD is non-negative, we do close it here.  */
> +        if (ISSET (FTS_NOCHDIR))
> +          {
> +            if (ISSET (FTS_CWDFD) && 0 <= fd)
> +              close (fd);
> +            return 0;
> +          }
> +
> +        if (fd < 0 && is_dotdot && ISSET (FTS_CWDFD))
> +          {
> +            /* When possible, skip the diropen and subsequent fstat+dev/ino
> +               comparison.  I.e., when changing to parent directory
> +               (chdir ("..")), use a file descriptor from the ring and
> +               save the overhead of diropen+fstat, as well as avoiding
> +               failure when we lack "x" access to the virtual cwd.  */
> +            if ( ! i_ring_empty (&sp->fts_fd_ring))
> +              {
> +                int parent_fd;
> +                fd_ring_print (sp, stderr, "pre-pop");
> +                parent_fd = i_ring_pop (&sp->fts_fd_ring);
> +                if (0 <= parent_fd)
> +                  {
> +                    fd = parent_fd;
> +                    dir = NULL;
> +                  }
> +              }
> +          }
> +
> +        int newfd = fd;
> +        if (fd < 0 && (newfd = diropen (sp, dir)) < 0)
> +          return -1;
> +
> +        /* The following dev/inode check is necessary if we're doing a
> +           "logical" traversal (through symlinks, a la chown -L), if the
> +           system lacks O_NOFOLLOW support, or if we're changing to ".."
> +           (but not via a popped file descriptor).  When changing to the
> +           name "..", O_NOFOLLOW can't help.  In general, when the target is
> +           not "..", diropen's use of O_NOFOLLOW ensures we don't mistakenly
> +           follow a symlink, so we can avoid the expense of this fstat.  */
> +        int ret;
> +        if (ISSET(FTS_LOGICAL) || ! HAVE_WORKING_O_NOFOLLOW
> +            || (dir && streq (dir, "..")))
> +          {
> +            struct STRUCT_STAT sb;
> +            if (FSTAT (newfd, &sb))
> +              {
> +                ret = -1;
> +                goto bail;
> +              }
> +            if (p->fts_statp->st_dev != sb.st_dev
> +                || p->fts_statp->st_ino != sb.st_ino)
> +              {
> +                __set_errno (ENOENT);           /* disinformation */
> +                ret = -1;
> +                goto bail;
> +              }
> +          }
> +
> +        if (ISSET(FTS_CWDFD))
> +          {
> +            cwd_advance_fd (sp, newfd, ! is_dotdot);
> +            return 0;
> +          }
> +
> +        ret = fchdir(newfd);
> +bail:
> +        if (fd < 0)
> +          {
> +            int oerrno = errno;
> +            (void)close(newfd);
> +            __set_errno (oerrno);
> +          }
> +        return ret;
> +}
> diff --git a/io/fts.c b/io/fts.c
> index 3825f0aeb4..d3b8e5a100 100644
> --- a/io/fts.c
> +++ b/io/fts.c
> @@ -1,2208 +1,23 @@
> -/* Traverse a file hierarchy.
> +/* File tree traversal functions LFS version.
> +   Copyright (C) 2026 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
>  
> -   Copyright (C) 2004-2026 Free Software Foundation, Inc.
> +   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.
>  
> -   This file 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.
> -
> -   This file is distributed in the hope that it will be useful,
> +   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.
> +   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 this program.  If not, see <https://www.gnu.org/licenses/>.  */
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
>  
> -/*-
> - * Copyright (c) 1990, 1993, 1994
> - *      The Regents of the University of California.  All rights reserved.
> - *
> - * Redistribution and use in source and binary forms, with or without
> - * modification, are permitted provided that the following conditions
> - * are met:
> - * 1. Redistributions of source code must retain the above copyright
> - *    notice, this list of conditions and the following disclaimer.
> - * 2. Redistributions in binary form must reproduce the above copyright
> - *    notice, this list of conditions and the following disclaimer in the
> - *    documentation and/or other materials provided with the distribution.
> - * 4. Neither the name of the University nor the names of its contributors
> - *    may be used to endorse or promote products derived from this software
> - *    without specific prior written permission.
> - *
> - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
> - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> - * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
> - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> - * SUCH DAMAGE.
> - */
> +#include <sys/types.h>
>  
> -#include <config.h>
> -
> -#if defined LIBC_SCCS && !defined GCC_LINT && !defined lint
> -static char sccsid[] = "@(#)fts.c       8.6 (Berkeley) 8/14/94";
> +#ifndef __OFF_T_MATCHES_OFF64_T
> +# include "io/fts-common.c"
>  #endif
> -
> -#if _LIBC
> -# include <fts.h>
> -#else
> -# include "fts_.h"
> -#endif
> -#if _LIBC || HAVE_SYS_PARAM_H
> -# include <sys/param.h>
> -#endif
> -#include <sys/stat.h>
> -#include <fcntl.h>
> -#include <errno.h>
> -#include <stddef.h>
> -#include <stdint.h>
> -#include <stdlib.h>
> -#include <string.h>
> -#include <unistd.h>
> -
> -/* Support for the LFS API version.  */
> -#ifndef FTS_OPEN
> -# define FTS_OPEN fts_open
> -# define FTS_CLOSE fts_close
> -# define FTS_READ fts_read
> -# define FTS_SET fts_set
> -# define FTS_CHILDREN fts_children
> -# define FTSOBJ FTS
> -# define FTSENTRY FTSENT
> -# define INO_T ino_t
> -# define STRUCT_STAT stat
> -# define FSTAT __fstat
> -# define FSTATAT __fstatat
> -# define STRUCT_STATFS statfs
> -# define FSTATFS __fstatfs
> -#endif
> -
> -#if ! _LIBC
> -# include "attribute.h"
> -# include "fcntl--.h"
> -# include "openat.h"
> -# include "opendirat.h"
> -# include "same-inode.h"
> -# define OPENDIRAT opendirat
> -# define FTSENT_WRAPPER(__p) __p
> -# define FTS_COMPAR_CAST(__fn) __fn
> -#else
> -# include <stdbool.h>
> -
> -# define internal_function
> -# define FALLTHROUGH               ; [[fallthrough]]
> -# define HAVE_STRUCT_DIRENT_D_TYPE 1
> -# define GNULIB_FTS_DEBUG          0
> -# ifdef O_PATH
> -#  define O_SEARCH                 O_PATH
> -# else
> -#  define O_SEARCH                 O_RDONLY
> -# endif
> -# define HAVE_SYS_VFS_H            1
> -# define HAVE_FSTATFS              1
> -# define HAVE_STRUCT_STATFS_F_TYPE 1
> -# define HAVE_OPENAT               1
> -# define HAVE_WORKING_O_NOFOLLOW   1
> -# define _GL_CMP(a, b)             ((a) < (b) ? -1 : (a) > (b))
> -# define OPENDIRAT                 __opendirat
> -
> -static inline bool openat_needs_fchdir (void)
> -{
> -  return false;
> -}
> -
> -static inline bool streq (const char *s1, const char *s2)
> -{
> -  return strcmp (s1, s2) == 0;
> -}
> -# define reallocarray              __libc_reallocarray
> -# define fchdir                    __fchdir
> -# define close                     __close
> -# define closedir                  __closedir
> -# define fcntl                     __fcntl
> -# define readdir                   __readdir
> -# ifndef dirfd
> -#  define dirfd                    __dirfd
> -# endif
> -# define open                      __open
> -# define openat                    __openat
> -
> -# include "cycle-check.c"
> -# include "i-ring.c"
> -
> -struct FTSENT_wrapper
> -{
> -  FTSOBJ *fts_fts;                /* the file hierarchy itself */
> -  DIR *fts_dirp;                  /* Dir pointer for any directory containing
> -				     more entries than we read at one time.  */
> -  struct STRUCT_STAT fts_stat;
> -
> -  FTSENTRY ent;
> -};
> -
> -/* glibc historicaly defines the FTS::fts_compar as having 'void *', while the
> -   fts_open has a function point using 'FTSENT **' as argument.  */
> -# define FTS_COMPAR_CAST(__fn) ((int (*) (void const *, void const *))__fn)
> -
> -# define FTSENT_WRAPPER(p) \
> -    ((struct FTSENT_wrapper *) ((char *)(p) - offsetof(struct FTSENT_wrapper, ent)))
> -#endif
> -#define FTSENT_FTS(p)   (FTSENT_WRAPPER(p)->fts_fts)
> -#define FTSENT_DIRP(p)  (FTSENT_WRAPPER(p)->fts_dirp)
> -
> -#include "flexmember.h"
> -
> -#include <dirent.h>
> -#ifndef _D_EXACT_NAMLEN
> -# define _D_EXACT_NAMLEN(dirent) strlen ((dirent)->d_name)
> -#endif
> -
> -#if HAVE_STRUCT_DIRENT_D_TYPE
> -/* True if the type of the directory entry D is known.  */
> -# define DT_IS_KNOWN(d) ((d)->d_type != DT_UNKNOWN)
> -/* True if the type of the directory entry D must be T.  */
> -# define DT_MUST_BE(d, t) ((d)->d_type == (t))
> -# define D_TYPE(d) ((d)->d_type)
> -#else
> -# define DT_IS_KNOWN(d) false
> -# define DT_MUST_BE(d, t) false
> -# define D_TYPE(d) DT_UNKNOWN
> -
> -# undef DT_UNKNOWN
> -# define DT_UNKNOWN 0
> -
> -/* Any nonzero values will do here, so long as they're distinct.
> -   Undef any existing macros out of the way.  */
> -# undef DT_BLK
> -# undef DT_CHR
> -# undef DT_DIR
> -# undef DT_FIFO
> -# undef DT_LNK
> -# undef DT_REG
> -# undef DT_SOCK
> -# define DT_BLK 1
> -# define DT_CHR 2
> -# define DT_DIR 3
> -# define DT_FIFO 4
> -# define DT_LNK 5
> -# define DT_REG 6
> -# define DT_SOCK 7
> -#endif
> -
> -#ifndef S_IFBLK
> -# define S_IFBLK 0
> -#endif
> -#ifndef S_IFLNK
> -# define S_IFLNK 0
> -#endif
> -#ifndef S_IFSOCK
> -# define S_IFSOCK 0
> -#endif
> -
> -enum
> -{
> -  NOT_AN_INODE_NUMBER = 0
> -};
> -
> -#ifdef D_INO_IN_DIRENT
> -# define D_INO(dp) (dp)->d_ino
> -#else
> -/* Some systems don't have inodes, so fake them to avoid lots of ifdefs.  */
> -# define D_INO(dp) NOT_AN_INODE_NUMBER
> -#endif
> -
> -/* If possible (see max_entries, below), read no more than this many directory
> -   entries at a time.  Without this limit (i.e., when using non-NULL
> -   fts_compar), processing a directory with 4,000,000 entries requires ~1GiB
> -   of memory, and handling 64M entries would require 16GiB of memory.  */
> -#ifndef FTS_MAX_READDIR_ENTRIES
> -# define FTS_MAX_READDIR_ENTRIES 100000
> -#endif
> -
> -/* If there are more than this many entries in a directory,
> -   and the conditions mentioned below are satisfied, then sort
> -   the entries on inode number before any further processing.  */
> -#ifndef FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
> -# define FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD 10000
> -#endif
> -
> -enum
> -{
> -  _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD = FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
> -};
> -
> -enum Fts_stat
> -{
> -  FTS_NO_STAT_REQUIRED = 1,
> -  FTS_STAT_REQUIRED = 2
> -};
> -
> -#ifndef __set_errno
> -# define __set_errno(Val) errno = (Val)
> -#endif
> -
> -/* If this host provides the openat function, then we can avoid
> -   attempting to open "." in some initialization code below.  */
> -#ifdef HAVE_OPENAT
> -# define HAVE_OPENAT_SUPPORT 1
> -#else
> -# define HAVE_OPENAT_SUPPORT 0
> -#endif
> -
> -#ifdef NDEBUG
> -# define fts_assert(expr) ((void) (0 && (expr)))
> -#else
> -# define fts_assert(expr)       \
> -    do                          \
> -      {                         \
> -        if (!(expr))            \
> -          abort ();             \
> -      }                         \
> -    while (false)
> -#endif
> -
> -static FTSENTRY  *fts_alloc (FTSOBJ *, const char *, size_t);
> -static FTSENTRY  *fts_build (FTSOBJ *, int);
> -static void      fts_lfree (FTSENTRY *);
> -static void      fts_load (FTSOBJ *, FTSENTRY *);
> -static size_t    fts_maxarglen (char * const *);
> -static void      fts_padjust (FTSOBJ *, FTSENTRY *);
> -static bool      fts_palloc (FTSOBJ *, size_t);
> -static FTSENTRY  *fts_sort (FTSOBJ *, FTSENTRY *, size_t);
> -static unsigned short int fts_stat (FTSOBJ *, FTSENTRY *, bool);
> -static int      fts_safe_changedir (FTSOBJ *, FTSENTRY *, int, const char *);
> -
> -#include "fts-cycle.c"
> -
> -#ifndef MAX
> -# define MAX(a,b) ((a) > (b) ? (a) : (b))
> -#endif
> -
> -#ifndef SIZE_MAX
> -# define SIZE_MAX ((size_t) -1)
> -#endif
> -
> -#define ISDOT(a)        (a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
> -
> -#define CLR(opt)        (sp->fts_options &= ~(opt))
> -#define ISSET(opt)      ((sp->fts_options & (opt)) != 0)
> -#define SET(opt)        (sp->fts_options |= (opt))
> -
> -/* FIXME: FTS_NOCHDIR is now misnamed.
> -   Call it FTS_USE_FULL_RELATIVE_FILE_NAMES instead. */
> -#define FCHDIR(sp, fd)                                  \
> -  (!ISSET(FTS_NOCHDIR) && (ISSET(FTS_CWDFD)             \
> -                           ? (cwd_advance_fd ((sp), (fd), true), 0) \
> -                           : fchdir (fd)))
> -
> -
> -/* fts_build flags */
> -/* FIXME: make this an enum */
> -#define BCHILD          1               /* fts_children */
> -#define BNAMES          2               /* fts_children, names only */
> -#define BREAD           3               /* fts_read */
> -
> -#if GNULIB_FTS_DEBUG
> -# include <inttypes.h>
> -# include <stdio.h>
> -bool fts_debug = false;
> -# define Dprintf(x) do { if (fts_debug) printf x; } while (false)
> -static void fd_ring_check (FTSOBJ const *);
> -static void fd_ring_print (FTSOBJ const *, FILE *, char const *);
> -#else
> -# define Dprintf(x)
> -# define fd_ring_check(x)
> -# define fd_ring_print(a, b, c)
> -#endif
> -
> -#define LEAVE_DIR(Fts, Ent, Tag)                                \
> -  do                                                            \
> -    {                                                           \
> -      Dprintf (("  %s-leaving: %s\n", Tag, (Ent)->fts_path));   \
> -      leave_dir (Fts, Ent);                                     \
> -      fd_ring_check (Fts);                                      \
> -    }                                                           \
> -  while (false)
> -
> -static void
> -fd_ring_clear (I_ring *fd_ring)
> -{
> -  while ( ! i_ring_empty (fd_ring))
> -    {
> -      int fd = i_ring_pop (fd_ring);
> -      if (0 <= fd)
> -        close (fd);
> -    }
> -}
> -
> -/* Overload the fts_statp->st_size member (otherwise unused, when
> -   fts_info is FTS_NSOK) to indicate whether fts_read should stat
> -   this entry or not.  */
> -static void
> -fts_set_stat_required (FTSENTRY *p, bool required)
> -{
> -  fts_assert (p->fts_info == FTS_NSOK);
> -  p->fts_statp->st_size = (required
> -                           ? FTS_STAT_REQUIRED
> -                           : FTS_NO_STAT_REQUIRED);
> -}
> -
> -/* Virtual fchdir.  Advance SP's working directory file descriptor,
> -   SP->fts_cwd_fd, to FD, and push the previous value onto the fd_ring.
> -   CHDIR_DOWN_ONE is true if FD corresponds to an entry in the directory
> -   open on sp->fts_cwd_fd; i.e., to move the working directory one level
> -   down.  */
> -static void
> -internal_function
> -cwd_advance_fd (FTSOBJ *sp, int fd, bool chdir_down_one)
> -{
> -  int old = sp->fts_cwd_fd;
> -  fts_assert (old != fd || old == AT_FDCWD);
> -
> -  if (chdir_down_one)
> -    {
> -      /* Push "old" onto the ring.
> -         If the displaced file descriptor is non-negative, close it.  */
> -      int prev_fd_in_slot = i_ring_push (&sp->fts_fd_ring, old);
> -      fd_ring_print (sp, stderr, "post-push");
> -      if (0 <= prev_fd_in_slot)
> -        close (prev_fd_in_slot); /* ignore any close failure */
> -    }
> -  else if ( ! ISSET (FTS_NOCHDIR))
> -    {
> -      if (0 <= old)
> -        close (old); /* ignore any close failure */
> -    }
> -
> -  sp->fts_cwd_fd = fd;
> -}
> -
> -/* Restore the initial, pre-traversal, "working directory".
> -   In FTS_CWDFD mode, we merely call cwd_advance_fd, otherwise,
> -   we may actually change the working directory.
> -   Return 0 upon success. Upon failure, set errno and return nonzero.  */
> -static int
> -restore_initial_cwd (FTSOBJ *sp)
> -{
> -  int fail = FCHDIR (sp, ISSET (FTS_CWDFD) ? AT_FDCWD : sp->fts_rfd);
> -  fd_ring_clear (&(sp->fts_fd_ring));
> -  return fail;
> -}
> -
> -/* Open the directory DIR if possible, and return a file
> -   descriptor.  Return -1 and set errno on failure.  It doesn't matter
> -   whether the file descriptor has read or write access.  */
> -
> -static int
> -internal_function
> -diropen (FTSOBJ const *sp, char const *dir)
> -{
> -  int open_flags = (O_SEARCH | O_CLOEXEC | O_DIRECTORY | O_NOCTTY | O_NONBLOCK
> -                    | (ISSET (FTS_PHYSICAL) ? O_NOFOLLOW : 0));
> -
> -  int fd = (ISSET (FTS_CWDFD)
> -            ? openat (sp->fts_cwd_fd, dir, open_flags)
> -            : open (dir, open_flags));
> -  return fd;
> -}
> -
> -FTSOBJ *
> -FTS_OPEN (char * const *argv,
> -          register int options,
> -          int (*compar) (const FTSENTRY **, const FTSENTRY **))
> -{
> -        /* Options check: glibc added other flags after FTS_NAMEONLY and
> -	   FTS_STOP, and they are assumed to be private.  */
> -        if (options & ~FTS_OPTIONMASK
> -#if _LIBC
> -	    || options & (FTS_NAMEONLY | FTS_STOP)
> -#endif
> -	    ) {
> -                __set_errno (EINVAL);
> -                return (NULL);
> -        }
> -        if ((options & FTS_NOCHDIR) && (options & FTS_CWDFD)) {
> -                __set_errno (EINVAL);
> -                return (NULL);
> -        }
> -#if !_LIBC
> -        if ( ! (options & (FTS_LOGICAL | FTS_PHYSICAL))) {
> -                __set_errno (EINVAL);
> -                return (NULL);
> -        }
> -#else
> -	/* glibc historically falls to FTS_PHYSICAL if no FTS_PHYSICAL or
> -	   FTS_LOGICAL is specified.  */
> -        if (! (options & (FTS_PHYSICAL | FTS_LOGICAL)))
> -	  options |= FTS_PHYSICAL;
> -#endif
> -
> -        /* Allocate/initialize the stream */
> -        register FTSOBJ *sp = calloc (1, sizeof *sp);
> -        if (sp == NULL)
> -                return (NULL);
> -        sp->fts_compar = FTS_COMPAR_CAST(compar);
> -        sp->fts_options = options;
> -
> -        /* Logical walks turn on NOCHDIR; symbolic links are too hard. */
> -        if (ISSET(FTS_LOGICAL)) {
> -                SET(FTS_NOCHDIR);
> -                CLR(FTS_CWDFD);
> -        }
> -
> -        /* Initialize fts_cwd_fd.  */
> -        sp->fts_cwd_fd = AT_FDCWD;
> -        if ( ISSET(FTS_CWDFD) && ! HAVE_OPENAT_SUPPORT)
> -          {
> -            /* While it isn't technically necessary to open "." this
> -               early, doing it here saves us the trouble of ensuring
> -               later (where it'd be messier) that "." can in fact
> -               be opened.  If not, revert to FTS_NOCHDIR mode.  */
> -            int fd = open (".", O_SEARCH | O_CLOEXEC);
> -            if (fd < 0)
> -              {
> -                /* Even if "." is unreadable, don't revert to FTS_NOCHDIR mode
> -                   on systems like Linux+PROC_FS, where our openat emulation
> -                   is good enough.  Note: on a system that emulates
> -                   openat via /proc, this technique can still fail, but
> -                   only in extreme conditions, e.g., when the working
> -                   directory cannot be saved (i.e. save_cwd fails) --
> -                   and that happens on Linux only when "." is unreadable
> -                   and the CWD would be longer than PATH_MAX.
> -                   FIXME: once Linux kernel openat support is well established,
> -                   replace the above open call and this entire if/else block
> -                   with the body of the if-block below.  */
> -                if ( openat_needs_fchdir ())
> -                  {
> -                    SET(FTS_NOCHDIR);
> -                    CLR(FTS_CWDFD);
> -                  }
> -              }
> -            else
> -              {
> -                close (fd);
> -              }
> -          }
> -
> -        /*
> -         * Start out with 1K of file name space, and enough, in any case,
> -         * to hold the user's file names.
> -         */
> -#ifndef MAXPATHLEN
> -# define MAXPATHLEN 1024
> -#endif
> -        {
> -          size_t maxarglen = fts_maxarglen(argv);
> -          if (! fts_palloc(sp, MAX(maxarglen, MAXPATHLEN)))
> -                  goto mem1;
> -        }
> -
> -        /* Allocate/initialize root's parent. */
> -        FTSENTRY *parent = NULL;
> -        if (*argv != NULL) {
> -                if ((parent = fts_alloc(sp, "", 0)) == NULL)
> -                        goto mem2;
> -                parent->fts_level = FTS_ROOTPARENTLEVEL;
> -          }
> -
> -        /* The classic fts implementation would call fts_stat with
> -           a new entry for each iteration of the loop below.
> -           If the comparison function is not specified or if the
> -           FTS_DEFER_STAT option is in effect, don't stat any entry
> -           in this loop.  This is an attempt to minimize the interval
> -           between the initial stat/lstat/fstatat and the point at which
> -           a directory argument is first opened.  This matters for any
> -           directory command line argument that resides on a file system
> -           without genuine i-nodes.  If you specify FTS_DEFER_STAT along
> -           with a comparison function, that function must not access any
> -           data via the fts_statp pointer.  */
> -        bool defer_stat = (compar == NULL || ISSET(FTS_DEFER_STAT));
> -
> -        /* Allocate/initialize root(s). */
> -        register FTSENTRY *root;
> -        register size_t nitems;
> -        FTSENTRY *tmp = NULL;     /* pacify gcc */
> -        for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
> -                /* *Do* allow zero-length file names. */
> -                size_t len = strlen(*argv);
> -
> -                if ( ! (options & FTS_VERBATIM))
> -                  {
> -                    /* If there are two or more trailing slashes, trim all but one,
> -                       but don't change "//" to "/", and do map "///" to "/".  */
> -                    char const *v = *argv;
> -                    if (2 < len && v[len - 1] == '/')
> -                      while (1 < len && v[len - 2] == '/')
> -                        --len;
> -                  }
> -
> -                register FTSENTRY *p = fts_alloc(sp, *argv, len);
> -                if (p == NULL)
> -                        goto mem3;
> -                p->fts_level = FTS_ROOTLEVEL;
> -                p->fts_parent = parent;
> -                p->fts_accpath = p->fts_name;
> -                /* Even when defer_stat is true, be sure to stat the first
> -                   command line argument, since fts_read (at least with
> -                   FTS_XDEV) requires that.  */
> -                if (defer_stat && root != NULL) {
> -                        p->fts_info = FTS_NSOK;
> -                        fts_set_stat_required(p, true);
> -                } else {
> -                        p->fts_info = fts_stat(sp, p, false);
> -                }
> -
> -                /*
> -                 * If comparison routine supplied, traverse in sorted
> -                 * order; otherwise traverse in the order specified.
> -                 */
> -                if (compar) {
> -                        p->fts_link = root;
> -                        root = p;
> -                } else {
> -                        p->fts_link = NULL;
> -                        if (root == NULL)
> -                                tmp = root = p;
> -                        else {
> -                                tmp->fts_link = p;
> -                                tmp = p;
> -                        }
> -                }
> -        }
> -        if (compar && nitems > 1)
> -                root = fts_sort(sp, root, nitems);
> -
> -        /*
> -         * Allocate a dummy pointer and make fts_read think that we've just
> -         * finished the node before the root(s); set p->fts_info to FTS_INIT
> -         * so that everything about the "current" node is ignored.
> -         */
> -        if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
> -                goto mem3;
> -        sp->fts_cur->fts_link = root;
> -        sp->fts_cur->fts_info = FTS_INIT;
> -        sp->fts_cur->fts_level = 1;
> -        if (! setup_dir (sp))
> -                goto mem3;
> -
> -        /*
> -         * If using chdir(2), grab a file descriptor pointing to dot to ensure
> -         * that we can get back here; this could be avoided for some file names,
> -         * but almost certainly not worth the effort.  Slashes, symbolic links,
> -         * and ".." are all fairly nasty problems.  Note, if we can't get the
> -         * descriptor we run anyway, just more slowly.
> -         */
> -        if (!ISSET(FTS_NOCHDIR) && !ISSET(FTS_CWDFD)
> -            && (sp->fts_rfd = diropen (sp, ".")) < 0)
> -                SET(FTS_NOCHDIR);
> -
> -        i_ring_init (&sp->fts_fd_ring, -1);
> -        return (sp);
> -
> -mem3:   fts_lfree(root);
> -        free(FTSENT_WRAPPER(parent));
> -mem2:   free(sp->fts_path);
> -mem1:   free(sp);
> -        return (NULL);
> -}
> -
> -static void
> -internal_function
> -fts_load (FTSOBJ *sp, register FTSENTRY *p)
> -{
> -        /*
> -         * Load the stream structure for the next traversal.  Since we don't
> -         * actually enter the directory until after the preorder visit, set
> -         * the fts_accpath field specially so the chdir gets done to the right
> -         * place and the user can access the first node.  From fts_open it's
> -         * known that the file name will fit.
> -         */
> -        register size_t len = p->fts_pathlen = p->fts_namelen;
> -        memmove(sp->fts_path, p->fts_name, len + 1);
> -        register char *cp = strrchr(p->fts_name, '/');
> -        if (cp && (cp != p->fts_name || cp[1])) {
> -                len = strlen(++cp);
> -                memmove(p->fts_name, cp, len + 1);
> -                p->fts_namelen = len;
> -        }
> -        p->fts_accpath = p->fts_path = sp->fts_path;
> -}
> -
> -int
> -FTS_CLOSE (FTSOBJ *sp)
> -{
> -        /*
> -         * This still works if we haven't read anything -- the dummy structure
> -         * points to the root list, so we step through to the end of the root
> -         * list which has a valid parent pointer.
> -         */
> -        if (sp->fts_cur) {
> -                register FTSENTRY *p;
> -                for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
> -                        register FTSENTRY *freep = p;
> -                        p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
> -                        free(FTSENT_WRAPPER(freep));
> -                }
> -                free(FTSENT_WRAPPER(p));
> -        }
> -
> -        /* Free up child linked list, sort array, file name buffer. */
> -        if (sp->fts_child)
> -                fts_lfree(sp->fts_child);
> -        free(sp->fts_array);
> -        free(sp->fts_path);
> -
> -        int saved_errno = 0;
> -        if (ISSET(FTS_CWDFD))
> -          {
> -            if (0 <= sp->fts_cwd_fd)
> -              if (close (sp->fts_cwd_fd))
> -                saved_errno = errno;
> -          }
> -        else if (!ISSET(FTS_NOCHDIR))
> -          {
> -            /* Return to original directory, save errno if necessary. */
> -            if (fchdir(sp->fts_rfd))
> -              saved_errno = errno;
> -
> -            /* If close fails, record errno only if saved_errno is zero,
> -               so that we report the probably-more-meaningful fchdir errno.  */
> -            if (close (sp->fts_rfd))
> -              if (saved_errno == 0)
> -                saved_errno = errno;
> -          }
> -
> -        fd_ring_clear (&sp->fts_fd_ring);
> -
> -        if (sp->fts_leaf_optimization_works_ht)
> -          hash_free (sp->fts_leaf_optimization_works_ht);
> -
> -        free_dir (sp);
> -
> -        /* Free up the stream pointer. */
> -        free(sp);
> -
> -        /* Set errno and return. */
> -        if (saved_errno) {
> -                __set_errno (saved_errno);
> -                return (-1);
> -        }
> -
> -        return (0);
> -}
> -
> -/* Minimum link count of a traditional Unix directory.  When leaf
> -   optimization is OK and a directory's st_nlink == MIN_DIR_NLINK,
> -   then the directory has no subdirectories.  */
> -enum { MIN_DIR_NLINK = 2 };
> -
> -/* Whether leaf optimization is OK for a directory.  */
> -enum leaf_optimization
> -  {
> -    /* st_nlink is not reliable for this directory's subdirectories.  */
> -    NO_LEAF_OPTIMIZATION,
> -
> -    /* st_nlink == 2 means the directory lacks subdirectories.  */
> -    OK_LEAF_OPTIMIZATION
> -  };
> -
> -#if (defined __linux__ || defined __ANDROID__) \
> -  && HAVE_SYS_VFS_H && HAVE_FSTATFS && HAVE_STRUCT_STATFS_F_TYPE
> -
> -# include <sys/vfs.h>
> -
> -/* Linux-specific constants from coreutils' src/fs.h */
> -# define S_MAGIC_AFS 0x5346414F
> -# define S_MAGIC_CIFS 0xFF534D42
> -# define S_MAGIC_LUSTRE 0x0BD00BD0
> -# define S_MAGIC_NFS 0x6969
> -# define S_MAGIC_PROC 0x9FA0
> -# define S_MAGIC_TMPFS 0x1021994
> -
> -# ifdef HAVE___FSWORD_T
> -typedef __fsword_t fsword;
> -# else
> -typedef long int fsword;
> -# endif
> -
> -/* Map a stat.st_dev number to a file system type number f_ftype.  */
> -struct dev_type
> -{
> -  dev_t st_dev;
> -  fsword f_type;
> -};
> -
> -/* Use a tiny initial size.  If a traversal encounters more than
> -   a few devices, the cost of growing/rehashing this table will be
> -   rendered negligible by the number of inodes processed.  */
> -enum { DEV_TYPE_HT_INITIAL_SIZE = 13 };
> -
> -static size_t
> -dev_type_hash (void const *x, size_t table_size)
> -{
> -  struct dev_type const *ax = x;
> -  uintmax_t dev = ax->st_dev;
> -  return dev % table_size;
> -}
> -
> -static bool
> -dev_type_compare (void const *x, void const *y)
> -{
> -  struct dev_type const *ax = x;
> -  struct dev_type const *ay = y;
> -  return ax->st_dev == ay->st_dev;
> -}
> -
> -/* Return the file system type of P with file descriptor FD, or 0 if not known.
> -   If FD is negative, P's file descriptor is unavailable.
> -   Try to cache known values.  */
> -
> -static fsword
> -filesystem_type (FTSENTRY const *p, int fd)
> -{
> -  FTSOBJ *sp = FTSENT_FTS(p);
> -
> -  /* If we're not in CWDFD mode, don't bother with this optimization,
> -     since the caller is not serious about performance.  */
> -  if (!ISSET (FTS_CWDFD))
> -    return 0;
> -
> -  Hash_table *h = sp->fts_leaf_optimization_works_ht;
> -  if (! h)
> -    h = sp->fts_leaf_optimization_works_ht
> -      = hash_initialize (DEV_TYPE_HT_INITIAL_SIZE, NULL, dev_type_hash,
> -                         dev_type_compare, free);
> -
> -  if (h)
> -    {
> -      struct dev_type tmp;
> -      tmp.st_dev = p->fts_statp->st_dev;
> -      struct dev_type *ent = hash_lookup (h, &tmp);
> -      if (ent)
> -        return ent->f_type;
> -    }
> -
> -  /* Look-up failed.  Query directly and cache the result.  */
> -  struct STRUCT_STATFS fs_buf;
> -  if (fd < 0 || FSTATFS (fd, &fs_buf) != 0)
> -    return 0;
> -
> -  if (h)
> -    {
> -      struct dev_type *t2 = malloc (sizeof *t2);
> -      if (t2)
> -        {
> -          t2->st_dev = p->fts_statp->st_dev;
> -          t2->f_type = fs_buf.f_type;
> -
> -          struct dev_type *ent = hash_insert (h, t2);
> -          if (ent)
> -            fts_assert (ent == t2);
> -          else
> -            free (t2);
> -        }
> -    }
> -
> -  return fs_buf.f_type;
> -}
> -
> -/* Return true if sorting dirents on inode numbers is known to improve
> -   traversal performance for the directory P with descriptor DIR_FD.
> -   Return false otherwise.  When in doubt, return true.
> -   DIR_FD is negative if unavailable.  */
> -static bool
> -dirent_inode_sort_may_be_useful (FTSENTRY const *p, int dir_fd)
> -{
> -  /* Skip the sort only if we can determine efficiently
> -     that skipping it is the right thing to do.
> -     The cost of performing an unnecessary sort is negligible,
> -     while the cost of *not* performing it can be O(N^2) with
> -     a very large constant.  */
> -
> -  switch (filesystem_type (p, dir_fd))
> -    {
> -    case S_MAGIC_LUSTRE:
> -      /* On Lustre, sorting directory entries interferes with its ability to
> -         prefetch file metadata (via statahead).  This would make a command
> -         like 'du' around 9 times slower.  See
> -         <https://bugs.gnu.org/80106>.  */
> -    case S_MAGIC_CIFS:
> -    case S_MAGIC_NFS:
> -    case S_MAGIC_TMPFS:
> -      /* On a file system of any of these types, sorting
> -         is unnecessary, and hence wasteful.  */
> -      return false;
> -
> -    default:
> -      return true;
> -    }
> -}
> -
> -/* Given an FTS entry P for a directory with descriptor DIR_FD,
> -   return whether it is valid to apply leaf optimization.
> -   The optimization is valid if a directory's st_nlink value equal
> -   to MIN_DIR_NLINK means the directory has no subdirectories.
> -   DIR_FD is negative if unavailable.  */
> -static enum leaf_optimization
> -leaf_optimization (FTSENTRY const *p, int dir_fd)
> -{
> -  switch (filesystem_type (p, dir_fd))
> -    {
> -    case 0:
> -      /* Leaf optimization is unsafe if the file system type is unknown.  */
> -      FALLTHROUGH;
> -    case S_MAGIC_AFS:
> -      /* Although AFS mount points are not counted in st_nlink, they
> -         act like directories.  See <https://bugs.debian.org/143111>.  */
> -      FALLTHROUGH;
> -    case S_MAGIC_CIFS:
> -      /* Leaf optimization causes 'find' to abort.  See
> -         <https://lists.gnu.org/r/bug-gnulib/2018-04/msg00015.html>.  */
> -      FALLTHROUGH;
> -    case S_MAGIC_NFS:
> -      /* NFS provides usable dirent.d_type but not necessarily for all entries
> -         of large directories, so as per <https://bugzilla.redhat.com/1252549>
> -         NFS should return true.  However st_nlink values are not accurate on
> -         all implementations as per <https://bugzilla.redhat.com/1299169>.  */
> -      FALLTHROUGH;
> -    case S_MAGIC_PROC:
> -      /* Per <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=143111> /proc
> -         may have bogus stat.st_nlink values.  */
> -      return NO_LEAF_OPTIMIZATION;
> -
> -    default:
> -      return OK_LEAF_OPTIMIZATION;
> -    }
> -}
> -
> -#else
> -static bool
> -dirent_inode_sort_may_be_useful (_GL_UNUSED FTSENTRY const *p,
> -                                 _GL_UNUSED int dir_fd)
> -{
> -  return true;
> -}
> -static enum leaf_optimization
> -leaf_optimization (_GL_UNUSED FTSENTRY const *p, _GL_UNUSED int dir_fd)
> -{
> -  return NO_LEAF_OPTIMIZATION;
> -}
> -#endif
> -
> -/*
> - * Special case of "/" at the end of the file name so that slashes aren't
> - * appended which would cause file names to be written as "....//foo".
> - */
> -#define NAPPEND(p)                                                      \
> -        (p->fts_path[p->fts_pathlen - 1] == '/'                         \
> -            ? p->fts_pathlen - 1 : p->fts_pathlen)
> -
> -FTSENTRY *
> -FTS_READ (FTSOBJ *sp)
> -{
> -        /* If finished or unrecoverable error, return NULL. */
> -        if (sp->fts_cur == NULL || ISSET(FTS_STOP))
> -                return (NULL);
> -
> -        /* Set current node pointer. */
> -        register FTSENTRY *p = sp->fts_cur;
> -
> -        /* Save and zero out user instructions. */
> -        register unsigned short int instr = p->fts_instr;
> -        p->fts_instr = FTS_NOINSTR;
> -
> -        /* Any type of file may be re-visited; re-stat and re-turn. */
> -        if (instr == FTS_AGAIN) {
> -                p->fts_info = fts_stat(sp, p, false);
> -                return (p);
> -        }
> -        Dprintf (("fts_read: p=%s\n",
> -                  p->fts_info == FTS_INIT ? "" : p->fts_path));
> -
> -        /*
> -         * Following a symlink -- SLNONE test allows application to see
> -         * SLNONE and recover.  If indirecting through a symlink, have
> -         * keep a pointer to current location.  If unable to get that
> -         * pointer, follow fails.
> -         */
> -        if (instr == FTS_FOLLOW &&
> -            (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
> -                p->fts_info = fts_stat(sp, p, true);
> -                if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
> -                        if ((p->fts_symfd = diropen (sp, ".")) < 0) {
> -                                p->fts_errno = errno;
> -                                p->fts_info = FTS_ERR;
> -                        } else
> -                                p->fts_flags |= FTS_SYMFOLLOW;
> -                }
> -                goto check_for_dir;
> -        }
> -
> -        /* Directory in pre-order. */
> -        if (p->fts_info == FTS_D) {
> -                /* If skipped or crossed mount point, do post-order visit. */
> -                if (instr == FTS_SKIP ||
> -                    (ISSET(FTS_XDEV) && p->fts_statp->st_dev != sp->fts_dev)) {
> -                        if (p->fts_flags & FTS_SYMFOLLOW)
> -                                (void)close(p->fts_symfd);
> -                        if (sp->fts_child) {
> -                                fts_lfree(sp->fts_child);
> -                                sp->fts_child = NULL;
> -                        }
> -                        p->fts_info = FTS_DP;
> -                        LEAVE_DIR (sp, p, "1");
> -                        return (p);
> -                }
> -
> -                /* Rebuild if only read the names and now traversing. */
> -                if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) {
> -                        CLR(FTS_NAMEONLY);
> -                        fts_lfree(sp->fts_child);
> -                        sp->fts_child = NULL;
> -                }
> -
> -                /*
> -                 * Cd to the subdirectory.
> -                 *
> -                 * If have already read and now fail to chdir, whack the list
> -                 * to make the names come out right, and set the parent errno
> -                 * so the application will eventually get an error condition.
> -                 * Set the FTS_DONTCHDIR flag so that when we logically change
> -                 * directories back to the parent we don't do a chdir.
> -                 *
> -                 * If haven't read do so.  If the read fails, fts_build sets
> -                 * FTS_STOP or the fts_info field of the node.
> -                 */
> -                if (sp->fts_child != NULL) {
> -                        if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
> -                                p->fts_errno = errno;
> -                                p->fts_flags |= FTS_DONTCHDIR;
> -                                for (p = sp->fts_child; p != NULL;
> -                                     p = p->fts_link)
> -                                        p->fts_accpath =
> -                                            p->fts_parent->fts_accpath;
> -                        }
> -                } else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
> -                        if (ISSET(FTS_STOP))
> -                                return (NULL);
> -                        /* If fts_build's call to fts_safe_changedir failed
> -                           because it was not able to fchdir into a
> -                           subdirectory, tell the caller.  */
> -                        if (p->fts_errno && p->fts_info != FTS_DNR)
> -                                p->fts_info = FTS_ERR;
> -                        LEAVE_DIR (sp, p, "2");
> -                        return (p);
> -                }
> -                p = sp->fts_child;
> -                sp->fts_child = NULL;
> -                goto name;
> -        }
> -
> -        /* Move to the next node on this level. */
> -next: ;
> -        register FTSENTRY *tmp = p;
> -
> -        /* If we have so many directory entries that we're reading them
> -           in batches, and we've reached the end of the current batch,
> -           read in a new batch.  */
> -        if (p->fts_link == NULL && FTSENT_DIRP(p->fts_parent))
> -          {
> -            p = tmp->fts_parent;
> -            sp->fts_cur = p;
> -            sp->fts_path[p->fts_pathlen] = '\0';
> -
> -            if ((p = fts_build (sp, BREAD)) == NULL)
> -              {
> -                if (ISSET(FTS_STOP))
> -                  return NULL;
> -                goto cd_dot_dot;
> -              }
> -
> -            free(FTSENT_WRAPPER(tmp));
> -            goto name;
> -          }
> -
> -        if ((p = p->fts_link) != NULL) {
> -                sp->fts_cur = p;
> -                free(FTSENT_WRAPPER(tmp));
> -
> -                /*
> -                 * If reached the top, return to the original directory (or
> -                 * the root of the tree), and load the file names for the next
> -                 * root.
> -                 */
> -                if (p->fts_level == FTS_ROOTLEVEL) {
> -                        if (restore_initial_cwd(sp)) {
> -                                SET(FTS_STOP);
> -                                return (NULL);
> -                        }
> -                        free_dir(sp);
> -                        fts_load(sp, p);
> -                        if (! setup_dir(sp)) {
> -                                free_dir(sp);
> -                                return (NULL);
> -                        }
> -                        goto check_for_dir;
> -                }
> -
> -                /*
> -                 * User may have called fts_set on the node.  If skipped,
> -                 * ignore.  If followed, get a file descriptor so we can
> -                 * get back if necessary.
> -                 */
> -                if (p->fts_instr == FTS_SKIP)
> -                        goto next;
> -                if (p->fts_instr == FTS_FOLLOW) {
> -                        p->fts_info = fts_stat(sp, p, true);
> -                        if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
> -                                if ((p->fts_symfd = diropen (sp, ".")) < 0) {
> -                                        p->fts_errno = errno;
> -                                        p->fts_info = FTS_ERR;
> -                                } else
> -                                        p->fts_flags |= FTS_SYMFOLLOW;
> -                        }
> -                        p->fts_instr = FTS_NOINSTR;
> -                }
> -
> -name:           {
> -                  register char *t = sp->fts_path + NAPPEND(p->fts_parent);
> -                  *t++ = '/';
> -                  memmove(t, p->fts_name, p->fts_namelen + 1);
> -                }
> -check_for_dir:
> -                sp->fts_cur = p;
> -                if (p->fts_info == FTS_NSOK)
> -                  {
> -                    if (p->fts_statp->st_size == FTS_STAT_REQUIRED)
> -                      p->fts_info = fts_stat(sp, p, false);
> -                    else
> -                      fts_assert (p->fts_statp->st_size == FTS_NO_STAT_REQUIRED);
> -                  }
> -
> -                /* Skip files with different device numbers when FTS_MOUNT
> -                   is set.  */
> -                if (ISSET (FTS_MOUNT) && p->fts_info != FTS_NS &&
> -                    p->fts_level != FTS_ROOTLEVEL &&
> -                    p->fts_statp->st_dev != sp->fts_dev)
> -                      goto next;
> -
> -                if (p->fts_info == FTS_D)
> -                  {
> -                    /* Now that P->fts_statp is guaranteed to be valid, if
> -                       this is a command-line directory, record its device
> -                       number, to be used for FTS_MOUNT and FTS_XDEV.  */
> -                    if (p->fts_level == FTS_ROOTLEVEL)
> -                      sp->fts_dev = p->fts_statp->st_dev;
> -                    Dprintf (("  entering: %s\n", p->fts_path));
> -                    if (! enter_dir (sp, p))
> -                      return NULL;
> -                  }
> -                return p;
> -        }
> -cd_dot_dot:
> -
> -        /* Move up to the parent node. */
> -        p = tmp->fts_parent;
> -        sp->fts_cur = p;
> -        free(FTSENT_WRAPPER(tmp));
> -
> -        if (p->fts_level == FTS_ROOTPARENTLEVEL) {
> -                /*
> -                 * Done; free everything up and set errno to 0 so the user
> -                 * can distinguish between error and EOF.
> -                 */
> -                free(FTSENT_WRAPPER(p));
> -                __set_errno (0);
> -                return (sp->fts_cur = NULL);
> -        }
> -
> -        fts_assert (p->fts_info != FTS_NSOK);
> -
> -        /* NUL terminate the file name.  */
> -        sp->fts_path[p->fts_pathlen] = '\0';
> -
> -        /*
> -         * Return to the parent directory.  If at a root node, restore
> -         * the initial working directory.  If we came through a symlink,
> -         * go back through the file descriptor.  Otherwise, move up
> -         * one level, via "..".
> -         */
> -        if (p->fts_level == FTS_ROOTLEVEL) {
> -                if (restore_initial_cwd(sp)) {
> -                        p->fts_errno = errno;
> -                        SET(FTS_STOP);
> -                }
> -        } else if (p->fts_flags & FTS_SYMFOLLOW) {
> -                if (FCHDIR(sp, p->fts_symfd)) {
> -                        p->fts_errno = errno;
> -                        SET(FTS_STOP);
> -                }
> -                (void)close(p->fts_symfd);
> -        } else if (!(p->fts_flags & FTS_DONTCHDIR) &&
> -                   fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
> -                p->fts_errno = errno;
> -                SET(FTS_STOP);
> -        }
> -
> -        /* If the directory causes a cycle, preserve the FTS_DC flag and keep
> -           the corresponding dev/ino pair in the hash table.  It is going to be
> -           removed when leaving the original directory.  */
> -        if (p->fts_info != FTS_DC) {
> -                p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
> -                if (p->fts_errno == 0)
> -                        LEAVE_DIR (sp, p, "3");
> -        }
> -        return ISSET(FTS_STOP) ? NULL : p;
> -}
> -
> -/*
> - * Fts_set takes the stream as an argument although it's not used in this
> - * implementation; it would be necessary if anyone wanted to add global
> - * semantics to fts using fts_set.  An error return is allowed for similar
> - * reasons.
> - */
> -/* ARGSUSED */
> -int
> -FTS_SET (_GL_UNUSED FTSOBJ *sp, FTSENTRY *p, int instr)
> -{
> -        if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
> -            instr != FTS_NOINSTR && instr != FTS_SKIP) {
> -                __set_errno (EINVAL);
> -                return (1);
> -        }
> -        p->fts_instr = instr;
> -        return (0);
> -}
> -
> -FTSENTRY *
> -FTS_CHILDREN (FTSOBJ *sp, int instr)
> -{
> -        if (instr != 0 && instr != FTS_NAMEONLY) {
> -                __set_errno (EINVAL);
> -                return (NULL);
> -        }
> -
> -        /* Set current node pointer. */
> -        register FTSENTRY *p = sp->fts_cur;
> -
> -        /*
> -         * Errno set to 0 so user can distinguish empty directory from
> -         * an error.
> -         */
> -        __set_errno (0);
> -
> -        /* Fatal errors stop here. */
> -        if (ISSET(FTS_STOP))
> -                return (NULL);
> -
> -        /* Return logical hierarchy of user's arguments. */
> -        if (p->fts_info == FTS_INIT)
> -                return (p->fts_link);
> -
> -        /*
> -         * If not a directory being visited in pre-order, stop here.  Could
> -         * allow FTS_DNR, assuming the user has fixed the problem, but the
> -         * same effect is available with FTS_AGAIN.
> -         */
> -        if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
> -                return (NULL);
> -
> -        /* Free up any previous child list. */
> -        if (sp->fts_child != NULL)
> -                fts_lfree(sp->fts_child);
> -
> -        if (instr == FTS_NAMEONLY) {
> -                SET(FTS_NAMEONLY);
> -                instr = BNAMES;
> -        } else
> -                instr = BCHILD;
> -
> -        /*
> -         * If using chdir on a relative file name and called BEFORE fts_read
> -         * does its chdir to the root of a traversal, we can lose -- we need to
> -         * chdir into the subdirectory, and we don't know where the current
> -         * directory is, so we can't get back so that the upcoming chdir by
> -         * fts_read will work.
> -         */
> -        if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
> -            ISSET(FTS_NOCHDIR))
> -                return (sp->fts_child = fts_build(sp, instr));
> -
> -        int fd = diropen (sp, ".");
> -        if (fd < 0)
> -                return (sp->fts_child = NULL);
> -        sp->fts_child = fts_build(sp, instr);
> -        if (ISSET(FTS_CWDFD))
> -          {
> -            cwd_advance_fd (sp, fd, true);
> -          }
> -        else
> -          {
> -            if (fchdir(fd))
> -              {
> -                int saved_errno = errno;
> -                close (fd);
> -                __set_errno (saved_errno);
> -                return NULL;
> -              }
> -            close (fd);
> -          }
> -        return (sp->fts_child);
> -}
> -
> -/* A comparison function to sort on increasing inode number.
> -   For some file system types, sorting either way makes a huge
> -   performance difference for a directory with very many entries,
> -   but sorting on increasing values is slightly better than sorting
> -   on decreasing values.  The difference is in the 5% range.  */
> -static int
> -fts_compare_ino (FTSENTRY const **a, FTSENTRY const **b)
> -{
> -  return _GL_CMP (a[0]->fts_statp->st_ino, b[0]->fts_statp->st_ino);
> -}
> -
> -/* Map the dirent.d_type value, DTYPE, to the corresponding stat.st_mode
> -   S_IF* bit and set ST.st_mode, thus clearing all other bits in that field.  */
> -static void
> -set_stat_type (struct STRUCT_STAT *st, unsigned int dtype)
> -{
> -  mode_t type;
> -  switch (dtype)
> -    {
> -    case DT_BLK:
> -      type = S_IFBLK;
> -      break;
> -    case DT_CHR:
> -      type = S_IFCHR;
> -      break;
> -    case DT_DIR:
> -      type = S_IFDIR;
> -      break;
> -    case DT_FIFO:
> -      type = S_IFIFO;
> -      break;
> -    case DT_LNK:
> -      type = S_IFLNK;
> -      break;
> -    case DT_REG:
> -      type = S_IFREG;
> -      break;
> -    case DT_SOCK:
> -      type = S_IFSOCK;
> -      break;
> -    default:
> -      type = 0;
> -    }
> -  st->st_mode = type;
> -}
> -
> -#define closedir_and_clear(dirp)                \
> -  do                                            \
> -    {                                           \
> -      closedir (dirp);                          \
> -      dirp = NULL;                              \
> -    }                                           \
> -  while (0)
> -
> -#define fts_opendir(file, Pdir_fd)                              \
> -        OPENDIRAT((! ISSET(FTS_NOCHDIR) && ISSET(FTS_CWDFD)     \
> -                   ? sp->fts_cwd_fd : AT_FDCWD),                \
> -                  file,                                         \
> -                  (((ISSET(FTS_PHYSICAL)                        \
> -                     && ! (ISSET(FTS_COMFOLLOW)                 \
> -                           && cur->fts_level == FTS_ROOTLEVEL)) \
> -                    ? O_NOFOLLOW : 0)),                         \
> -                  Pdir_fd)
> -
> -/*
> - * This is the tricky part -- do not casually change *anything* in here.  The
> - * idea is to build the linked list of entries that are used by fts_children
> - * and fts_read.  There are lots of special cases.
> - *
> - * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
> - * set and it's a physical walk (so that symbolic links can't be directories),
> - * we can do things quickly.  First, if it's a 4.4BSD file system, the type
> - * of the file is in the directory entry.  Otherwise, we assume that the number
> - * of subdirectories in a node is equal to the number of links to the parent.
> - * The former skips all stat calls.  The latter skips stat calls in any leaf
> - * directories and for any files after the subdirectories in the directory have
> - * been found, cutting the stat calls by about 2/3.
> - */
> -static FTSENTRY *
> -internal_function
> -fts_build (register FTSOBJ *sp, int type)
> -{
> -        FTSENTRY *cur = sp->fts_cur;
> -        bool continue_readdir = !!FTSENT_DIRP(cur);
> -
> -        /* When cur->fts_dirp is non-NULL, that means we should
> -           continue calling readdir on that existing DIR* pointer
> -           rather than opening a new one.  */
> -        int dir_fd;
> -        if (continue_readdir)
> -          {
> -            DIR *dp = FTSENT_DIRP(cur);
> -            dir_fd = dirfd (dp);
> -            if (dir_fd < 0)
> -              {
> -                int dirfd_errno = errno;
> -                closedir_and_clear (FTSENT_DIRP(cur));
> -                if (type == BREAD)
> -                  {
> -                    cur->fts_info = FTS_DNR;
> -                    cur->fts_errno = dirfd_errno;
> -                  }
> -                return NULL;
> -              }
> -          }
> -        else
> -          {
> -            /* Open the directory for reading.  If this fails, we're done.
> -               If being called from fts_read, set the fts_info field. */
> -            if ((FTSENT_DIRP (cur) = fts_opendir(cur->fts_accpath, &dir_fd)) == NULL)
> -              {
> -                if (type == BREAD)
> -                  {
> -                    cur->fts_info = FTS_DNR;
> -                    cur->fts_errno = errno;
> -                  }
> -                return NULL;
> -              }
> -            /* Rather than calling fts_stat for each and every entry encountered
> -               in the readdir loop (below), stat each directory only right after
> -               opening it.  */
> -            bool stat_optimization = cur->fts_info == FTS_NSOK;
> -
> -            if (stat_optimization
> -                /* Also read the stat info again after opening a directory to
> -                   reveal eventual changes caused by a submount triggered by
> -                   the traversal.  But do it only for utilities which use
> -                   FTS_TIGHT_CYCLE_CHECK.  Therefore, only find and du
> -                   benefit/suffer from this feature for now.  */
> -                || ISSET (FTS_TIGHT_CYCLE_CHECK))
> -              {
> -                if (!stat_optimization)
> -                  LEAVE_DIR (sp, cur, "4");
> -                if (FSTAT (dir_fd, cur->fts_statp) != 0)
> -                  {
> -                    int fstat_errno = errno;
> -                    closedir_and_clear (FTSENT_DIRP(cur));
> -                    if (type == BREAD)
> -                      {
> -                        cur->fts_errno = fstat_errno;
> -                        cur->fts_info = FTS_NS;
> -                      }
> -                    __set_errno (fstat_errno);
> -                    return NULL;
> -                  }
> -                if (stat_optimization)
> -                  cur->fts_info = FTS_D;
> -                else if (! enter_dir (sp, cur))
> -                  {
> -                    int saved_errno = errno;
> -                    closedir_and_clear (FTSENT_DIRP(cur));
> -                    __set_errno (saved_errno);
> -                    return NULL;
> -                  }
> -              }
> -          }
> -
> -        /* Maximum number of readdir entries to read at one time.  This
> -           limitation is to avoid reading millions of entries into memory
> -           at once.  When an fts_compar function is specified, we have no
> -           choice: we must read all entries into memory before calling that
> -           function.  But when no such function is specified, we can read
> -           entries in batches that are large enough to help us with inode-
> -           sorting, yet not so large that we risk exhausting memory.  */
> -        size_t max_entries = sp->fts_compar ? SIZE_MAX : FTS_MAX_READDIR_ENTRIES;
> -
> -        /*
> -         * If we're going to need to stat anything or we want to descend
> -         * and stay in the directory, chdir.  If this fails we keep going,
> -         * but set a flag so we don't chdir after the post-order visit.
> -         * We won't be able to stat anything, but we can still return the
> -         * names themselves.  Note, that since fts_read won't be able to
> -         * chdir into the directory, it will have to return different file
> -         * names than before, i.e. "a/b" instead of "b".  Since the node
> -         * has already been visited in pre-order, have to wait until the
> -         * post-order visit to return the error.  There is a special case
> -         * here, if there was nothing to stat then it's not an error to
> -         * not be able to stat.  This is all fairly nasty.  If a program
> -         * needed sorted entries or stat information, they had better be
> -         * checking FTS_NS on the returned nodes.
> -         */
> -        bool descend;
> -        if (continue_readdir)
> -          {
> -            /* When resuming a short readdir run, we already have
> -               the required dirp and dir_fd.  */
> -            descend = true;
> -          }
> -        else
> -          {
> -            /* Try to descend unless it is a names-only fts_children,
> -               or the directory is known to lack subdirectories.  */
> -            descend = (type != BNAMES
> -                       && ! (ISSET (FTS_NOSTAT) && ISSET (FTS_PHYSICAL)
> -                             && ! ISSET (FTS_SEEDOT)
> -                             && cur->fts_statp->st_nlink == MIN_DIR_NLINK
> -                             && (leaf_optimization (cur, dir_fd)
> -                                 != NO_LEAF_OPTIMIZATION)));
> -            if (descend || type == BREAD)
> -              {
> -                if (ISSET(FTS_CWDFD))
> -                  dir_fd = fcntl (dir_fd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1);
> -                if (dir_fd < 0 || fts_safe_changedir(sp, cur, dir_fd, NULL)) {
> -                        if (descend && type == BREAD)
> -                                cur->fts_errno = errno;
> -                        cur->fts_flags |= FTS_DONTCHDIR;
> -                        descend = false;
> -                        closedir_and_clear(FTSENT_DIRP(cur));
> -                        if (ISSET(FTS_CWDFD) && 0 <= dir_fd)
> -                                close (dir_fd);
> -                        FTSENT_DIRP(cur) = NULL;
> -                } else
> -                        descend = true;
> -              }
> -          }
> -
> -        /*
> -         * Figure out the max file name length that can be stored in the
> -         * current buffer -- the inner loop allocates more space as necessary.
> -         * We really wouldn't have to do the maxlen calculations here, we
> -         * could do them in fts_read before returning the name, but it's a
> -         * lot easier here since the length is part of the dirent structure.
> -         *
> -         * If not changing directories set a pointer so that can just append
> -         * each new component into the file name.
> -         */
> -        size_t len = NAPPEND(cur);
> -        char *cp;
> -        if (ISSET(FTS_NOCHDIR)) {
> -                cp = sp->fts_path + len;
> -                *cp++ = '/';
> -        } else {
> -                /* GCC, you're too verbose. */
> -                cp = NULL;
> -        }
> -        len++;
> -        size_t maxlen = sp->fts_pathlen - len;
> -
> -        ptrdiff_t level = cur->fts_level + 1;
> -
> -        /* Read the directory, attaching each entry to the "link" pointer. */
> -        bool doadjust = false;
> -        register FTSENTRY *head = NULL;
> -        FTSENTRY *tail = NULL;
> -        register size_t nitems = 0;
> -        bool sort_by_inode = false;
> -        while (FTSENT_DIRP(cur)) {
> -                __set_errno (0);
> -                struct dirent *dp = readdir(FTSENT_DIRP(cur));
> -                if (dp == NULL) {
> -                        /* Some readdir()s do not absorb ENOENT (dir
> -                           deleted but open).  This bug was fixed in
> -                           glibc 2.3 (2002).  */
> -#if ! (2 < __GLIBC__ + (3 <= __GLIBC_MINOR__))
> -                        if (errno == ENOENT)
> -                          errno = 0;
> -#endif
> -                        if (errno) {
> -                                cur->fts_errno = errno;
> -                                /* If we've not read any items yet, treat
> -                                   the error as if we can't access the dir.  */
> -                                cur->fts_info = (continue_readdir || nitems)
> -                                                ? FTS_ERR : FTS_DNR;
> -                        }
> -                        closedir_and_clear(FTSENT_DIRP(cur));
> -                        break;
> -                }
> -                if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
> -                        continue;
> -
> -                size_t d_namelen = _D_EXACT_NAMLEN (dp);
> -                register FTSENTRY *p = fts_alloc (sp, dp->d_name, d_namelen);
> -                if (!p)
> -                        goto mem1;
> -                if (d_namelen >= maxlen) {
> -                        /* include space for NUL */
> -                        uintptr_t oldaddr = (uintptr_t) sp->fts_path;
> -                        if (! fts_palloc(sp, d_namelen + len + 1)) {
> -                                /*
> -                                 * No more memory.  Save
> -                                 * errno, free up the current structure and the
> -                                 * structures already allocated.
> -                                 */
> -mem1: ;
> -                                int saved_errno = errno;
> -                                free(FTSENT_WRAPPER(p));
> -                                fts_lfree(head);
> -                                closedir_and_clear(FTSENT_DIRP(cur));
> -                                cur->fts_info = FTS_ERR;
> -                                SET(FTS_STOP);
> -                                __set_errno (saved_errno);
> -                                return (NULL);
> -                        }
> -                        /* Did realloc() change the pointer? */
> -                        if (oldaddr != (uintptr_t) sp->fts_path) {
> -                                doadjust = true;
> -                                if (ISSET(FTS_NOCHDIR))
> -                                        cp = sp->fts_path + len;
> -                        }
> -                        maxlen = sp->fts_pathlen - len;
> -                }
> -
> -                size_t new_len = len + d_namelen;
> -                if (new_len < len) {
> -                        /*
> -                         * In the unlikely event that we would end up
> -                         * with a file name longer than SIZE_MAX, free up
> -                         * the current structure and the structures already
> -                         * allocated, then error out with ENAMETOOLONG.
> -                         */
> -                        free(FTSENT_WRAPPER(p));
> -                        fts_lfree(head);
> -                        closedir_and_clear(FTSENT_DIRP(cur));
> -                        cur->fts_info = FTS_ERR;
> -                        SET(FTS_STOP);
> -                        __set_errno (ENAMETOOLONG);
> -                        return (NULL);
> -                }
> -                p->fts_level = level;
> -                p->fts_parent = sp->fts_cur;
> -                p->fts_pathlen = new_len;
> -
> -                /* Store dirent.d_ino, in case we need to sort
> -                   entries before processing them.  */
> -                p->fts_statp->st_ino = D_INO (dp);
> -
> -                /* Build a file name for fts_stat to stat. */
> -                if (ISSET(FTS_NOCHDIR)) {
> -                        p->fts_accpath = p->fts_path;
> -                        memmove(cp, p->fts_name, p->fts_namelen + 1);
> -                } else
> -                        p->fts_accpath = p->fts_name;
> -
> -                if (sp->fts_compar == NULL || ISSET(FTS_DEFER_STAT)) {
> -                        /* Record what fts_read will have to do with this
> -                           entry. In many cases, it will simply fts_stat it,
> -                           but we can take advantage of any d_type information
> -                           to optimize away the unnecessary stat calls.  I.e.,
> -                           if FTS_NOSTAT is in effect, we don't need device
> -                           numbers unconditionally (FTS_MOUNT) and we're not
> -                           following symlinks (FTS_PHYSICAL) and d_type
> -                           indicates this is *not* a directory, then we won't
> -                           have to stat it  at all.  If it *is* a directory,
> -                           then (currently) we stat it regardless, in order to
> -                           get device and inode numbers.  Some day we might
> -                           optimize that away, too, for directories where
> -                           d_ino is known to be valid.  */
> -                        bool skip_stat = (ISSET(FTS_NOSTAT)
> -                                          && DT_IS_KNOWN(dp)
> -                                          && ! DT_MUST_BE(dp, DT_DIR)
> -                                          && (ISSET(FTS_PHYSICAL)
> -                                              || ! DT_MUST_BE(dp, DT_LNK))
> -                                          && ! ISSET(FTS_MOUNT));
> -                        p->fts_info = FTS_NSOK;
> -                        /* Propagate dirent.d_type information back
> -                           to caller, when possible.  */
> -                        set_stat_type (p->fts_statp, D_TYPE (dp));
> -                        fts_set_stat_required(p, !skip_stat);
> -                } else {
> -                        p->fts_info = fts_stat(sp, p, false);
> -                }
> -
> -                /* We walk in directory order so "ls -f" doesn't get upset. */
> -                p->fts_link = NULL;
> -                if (head == NULL)
> -                        head = tail = p;
> -                else {
> -                        tail->fts_link = p;
> -                        tail = p;
> -                }
> -
> -                /* If there are many entries, no sorting function has been
> -                   specified, and this file system is of a type that may be
> -                   slow with a large number of entries, arrange to sort the
> -                   directory entries on increasing inode numbers.
> -
> -                   The NITEMS comparison uses ==, not >, because the test
> -                   needs to be tried at most once once, and NITEMS will exceed
> -                   the threshold after it is incremented below.  */
> -                if (nitems == _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
> -                    && !sp->fts_compar)
> -                  sort_by_inode = dirent_inode_sort_may_be_useful (cur, dir_fd);
> -
> -                ++nitems;
> -                if (max_entries <= nitems) {
> -                        /* When there are too many dir entries, leave
> -                           fts_dirp open, so that a subsequent fts_read
> -                           can take up where we leave off.  */
> -                        break;
> -                }
> -        }
> -
> -        /*
> -         * If realloc() changed the address of the file name, adjust the
> -         * addresses for the rest of the tree and the dir list.
> -         */
> -        if (doadjust)
> -                fts_padjust(sp, head);
> -
> -        /*
> -         * If not changing directories, reset the file name back to original
> -         * state.
> -         */
> -        if (ISSET(FTS_NOCHDIR)) {
> -                if (len == sp->fts_pathlen || nitems == 0)
> -                        --cp;
> -                *cp = '\0';
> -        }
> -
> -        /*
> -         * If descended after called from fts_children or after called from
> -         * fts_read and nothing found, get back.  At the root level we use
> -         * the saved fd; if one of fts_open()'s arguments is a relative name
> -         * to an empty directory, we wind up here with no other way back.  If
> -         * can't get back, we're done.
> -         */
> -        if (!continue_readdir && descend && (type == BCHILD || !nitems) &&
> -            (cur->fts_level == FTS_ROOTLEVEL
> -             ? restore_initial_cwd(sp)
> -             : fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
> -                cur->fts_info = FTS_ERR;
> -                SET(FTS_STOP);
> -                fts_lfree(head);
> -                return (NULL);
> -        }
> -
> -        /* If didn't find anything, return NULL. */
> -        if (!nitems) {
> -                if (type == BREAD
> -                    && cur->fts_info != FTS_DNR && cur->fts_info != FTS_ERR)
> -                        cur->fts_info = FTS_DP;
> -                fts_lfree(head);
> -                return (NULL);
> -        }
> -
> -        if (sort_by_inode) {
> -                sp->fts_compar = FTS_COMPAR_CAST (fts_compare_ino);
> -                head = fts_sort (sp, head, nitems);
> -                sp->fts_compar = NULL;
> -        }
> -
> -        /* Sort the entries. */
> -        if (sp->fts_compar && nitems > 1)
> -                head = fts_sort(sp, head, nitems);
> -        return (head);
> -}
> -
> -#if GNULIB_FTS_DEBUG
> -
> -struct devino {
> -  intmax_t dev, ino;
> -};
> -#define PRINT_DEVINO "(%jd,%jd)"
> -
> -static struct devino
> -getdevino (int fd)
> -{
> -  struct STRUCT_STAT st;
> -  return (fd == AT_FDCWD
> -          ? (struct devino) { -1, 0 }
> -          : FSTAT (fd, &st) == 0
> -          ? (struct devino) { st.st_dev, st.st_ino }
> -          : (struct devino) { -1, errno });
> -}
> -
> -/* Walk ->fts_parent links starting at E_CURR, until the root of the
> -   current hierarchy.  There should be a directory with dev/inode
> -   matching those of AD.  If not, print a lot of diagnostics.  */
> -static void
> -find_matching_ancestor (FTSENTRY const *e_curr, struct Active_dir const *ad)
> -{
> -  for (FTSENTRY const *ent = e_curr;
> -       ent->fts_level >= FTS_ROOTLEVEL;
> -       ent = ent->fts_parent)
> -    {
> -      if (ad->ino == ent->fts_statp->st_ino
> -          && ad->dev == ent->fts_statp->st_dev)
> -        return;
> -    }
> -  printf ("ERROR: tree dir, %s, not active\n", ad->fts_ent->fts_accpath);
> -  printf ("active dirs:\n");
> -  for (FTSENTRY const *ent = e_curr;
> -       ent->fts_level >= FTS_ROOTLEVEL;
> -       ent = ent->fts_parent)
> -    printf ("  %s(%"PRIuMAX"/%"PRIuMAX") to %s(%"PRIuMAX"/%"PRIuMAX")...\n",
> -            ad->fts_ent->fts_accpath,
> -            (uintmax_t) ad->dev,
> -            (uintmax_t) ad->ino,
> -            ent->fts_accpath,
> -            (uintmax_t) ent->fts_statp->st_dev,
> -            (uintmax_t) ent->fts_statp->st_ino);
> -}
> -
> -void
> -fts_cross_check (FTSOBJ const *sp)
> -{
> -  if ( ! ISSET (FTS_TIGHT_CYCLE_CHECK))
> -    return;
> -
> -  FTSENTRY const *ent = sp->fts_cur;
> -
> -  Dprintf (("fts-cross-check cur=%s\n", ent->fts_path));
> -  /* Make sure every parent dir is in the tree.  */
> -  for (FTSENTRY const *t = ent->fts_parent;
> -       t->fts_level >= FTS_ROOTLEVEL;
> -       t = t->fts_parent)
> -    {
> -      struct Active_dir ad;
> -      ad.ino = t->fts_statp->st_ino;
> -      ad.dev = t->fts_statp->st_dev;
> -      if ( ! hash_lookup (sp->fts_cycle.ht, &ad))
> -        printf ("ERROR: active dir, %s, not in tree\n", t->fts_path);
> -    }
> -
> -  /* Make sure every dir in the tree is an active dir.
> -     But ENT is not necessarily a directory.  If so, just skip this part. */
> -  if (ent->fts_parent->fts_level >= FTS_ROOTLEVEL
> -      && (ent->fts_info == FTS_DP
> -          || ent->fts_info == FTS_D))
> -    for (struct Active_dir *ad = hash_get_first (sp->fts_cycle.ht);
> -         ad != NULL;
> -         ad = hash_get_next (sp->fts_cycle.ht, ad))
> -      {
> -        find_matching_ancestor (ent, ad);
> -      }
> -}
> -
> -static bool
> -same_fd (int fd1, int fd2)
> -{
> -  struct STRUCT_STAT sb1, sb2;
> -  return (FSTAT (fd1, &sb1) == 0
> -          && FSTAT (fd2, &sb2) == 0
> -          && psame_inode (&sb1, &sb2));
> -}
> -
> -static void
> -fd_ring_print (FTSOBJ const *sp, FILE *stream, char const *msg)
> -{
> -  if (!fts_debug)
> -    return;
> -  I_ring const *fd_ring = &sp->fts_fd_ring;
> -  struct devino cwd = getdevino (sp->fts_cwd_fd);
> -  fprintf (stream, "=== %s ========== "PRINT_DEVINO"\n", msg, cwd.dev, cwd.ino);
> -  if (i_ring_empty (fd_ring))
> -    return;
> -
> -  unsigned int i = fd_ring->ir_front;
> -  while (true)
> -    {
> -      int fd = fd_ring->ir_data[i];
> -      if (fd < 0)
> -        fprintf (stream, "%u: %d:\n", i, fd);
> -      else
> -        {
> -          struct devino wd = getdevino (fd);
> -          fprintf (stream, "%u: %d: "PRINT_DEVINO"\n", i, fd, wd.dev, wd.ino);
> -        }
> -      if (i == fd_ring->ir_back)
> -        break;
> -      i = (i + I_RING_SIZE - 1) % I_RING_SIZE;
> -    }
> -}
> -
> -/* Ensure that each file descriptor on the fd_ring matches a
> -   parent, grandparent, etc. of the current working directory.  */
> -static void
> -fd_ring_check (FTSOBJ const *sp)
> -{
> -  if (!fts_debug)
> -    return;
> -
> -  /* Make a writable copy.  */
> -  I_ring fd_w = sp->fts_fd_ring;
> -
> -  int cwd_fd = sp->fts_cwd_fd;
> -  cwd_fd = fcntl (cwd_fd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1);
> -  struct devino dot = getdevino (cwd_fd);
> -  fprintf (stderr, "===== check ===== cwd: "PRINT_DEVINO"\n",
> -           dot.dev, dot.ino);
> -  while ( ! i_ring_empty (&fd_w))
> -    {
> -      int fd = i_ring_pop (&fd_w);
> -      if (0 <= fd)
> -        {
> -          int open_flags = O_SEARCH | O_CLOEXEC;
> -          int parent_fd = openat (cwd_fd, "..", open_flags);
> -          if (parent_fd < 0)
> -            {
> -              // Warn?
> -              break;
> -            }
> -          if (!same_fd (fd, parent_fd))
> -            {
> -              struct devino cwd = getdevino (fd);
> -              fprintf (stderr, "ring  : "PRINT_DEVINO"\n", cwd.dev, cwd.ino);
> -              struct devino c2 = getdevino (parent_fd);
> -              fprintf (stderr, "parent: "PRINT_DEVINO"\n", c2.dev, c2.ino);
> -              fts_assert (0);
> -            }
> -          close (cwd_fd);
> -          cwd_fd = parent_fd;
> -        }
> -    }
> -  close (cwd_fd);
> -}
> -#endif
> -
> -static unsigned short int
> -internal_function
> -fts_stat(FTSOBJ *sp, register FTSENTRY *p, bool follow)
> -{
> -        if (ISSET (FTS_LOGICAL)
> -            || (ISSET (FTS_COMFOLLOW) && p->fts_level == FTS_ROOTLEVEL))
> -                follow = true;
> -
> -        struct STRUCT_STAT *sbp = p->fts_statp;
> -
> -        /*
> -         * If doing a logical walk, or application requested FTS_FOLLOW, do
> -         * a stat(2).  If that fails, check for a nonexistent symlink.  If
> -         * fail, set the errno from the stat call.
> -         */
> -        int flags = follow ? 0 : AT_SYMLINK_NOFOLLOW;
> -        if (FSTATAT (sp->fts_cwd_fd, p->fts_accpath, sbp, flags) < 0)
> -          {
> -            if (follow && errno == ENOENT
> -                && 0 <= FSTATAT (sp->fts_cwd_fd, p->fts_accpath, sbp,
> -                                 AT_SYMLINK_NOFOLLOW))
> -              {
> -                __set_errno (0);
> -                return FTS_SLNONE;
> -              }
> -
> -            p->fts_errno = errno;
> -           memset (sbp, 0, sizeof *sbp);
> -            return FTS_NS;
> -          }
> -
> -        if (S_ISDIR(sbp->st_mode)) {
> -                if (ISDOT(p->fts_name)) {
> -                        /* Command-line "." and ".." are real directories. */
> -                        return (p->fts_level == FTS_ROOTLEVEL ? FTS_D : FTS_DOT);
> -                }
> -
> -                return (FTS_D);
> -        }
> -        if (S_ISLNK(sbp->st_mode))
> -                return (FTS_SL);
> -        if (S_ISREG(sbp->st_mode))
> -                return (FTS_F);
> -        return (FTS_DEFAULT);
> -}
> -
> -static int
> -fts_compar (void const *a, void const *b)
> -{
> -  /* Convert A and B to the correct types, to pacify the compiler, and
> -     for portability to bizarre hosts where "void const *" and "FTSENT
> -     const **" differ in runtime representation.  The comparison
> -     function cannot modify *a and *b, but there is no compile-time
> -     check for this.  */
> -  FTSENTRY const **pa = (FTSENTRY const **) a;
> -  FTSENTRY const **pb = (FTSENTRY const **) b;
> -  return FTSENT_FTS(pa[0])->fts_compar (pa, pb);
> -}
> -
> -static FTSENTRY *
> -internal_function
> -fts_sort (FTSOBJ *sp, FTSENTRY *head, register size_t nitems)
> -{
> -        register FTSENTRY **ap, *p;
> -
> -        /* On most modern hosts, void * and FTSENT ** have the same
> -           run-time representation, and one can convert sp->fts_compar to
> -           the type qsort expects without problem.  Use the heuristic that
> -           this is OK if the two pointer types are the same size, and if
> -           converting FTSENT ** to uintptr_t is the same as converting
> -           FTSENT ** to void * and then to uintptr_t.  This heuristic isn't
> -           valid in general but we don't know of any counterexamples.  */
> -        FTSENTRY *dummy;
> -        int (*compare) (void const *, void const *) =
> -          ((sizeof &dummy == sizeof (void *)
> -            && (uintptr_t) &dummy == (uintptr_t) (void *) &dummy)
> -           ? (int (*) (void const *, void const *)) sp->fts_compar
> -           : fts_compar);
> -
> -        /*
> -         * Construct an array of pointers to the structures and call qsort(3).
> -         * Reassemble the array in the order returned by qsort.  If unable to
> -         * sort for memory reasons, return the directory entries in their
> -         * current order.  Allocate enough space for the current needs plus
> -         * 40 so don't realloc one entry at a time.
> -         */
> -        if (nitems > sp->fts_nitems) {
> -                sp->fts_nitems = nitems + 40;
> -                FTSENTRY **a;
> -                if (! (a = reallocarray (sp->fts_array,
> -                                         sp->fts_nitems, sizeof *a))) {
> -                        free(sp->fts_array);
> -                        sp->fts_array = NULL;
> -                        sp->fts_nitems = 0;
> -                        return (head);
> -                }
> -                sp->fts_array = a;
> -        }
> -        for (ap = sp->fts_array, p = head; p; p = p->fts_link)
> -                *ap++ = p;
> -        qsort((void *)sp->fts_array, nitems, sizeof(FTSENTRY *), compare);
> -        for (head = *(ap = sp->fts_array); --nitems; ++ap)
> -                ap[0]->fts_link = ap[1];
> -        ap[0]->fts_link = NULL;
> -        return (head);
> -}
> -
> -static FTSENTRY *
> -internal_function
> -fts_alloc (FTSOBJ *sp, const char *name, register size_t namelen)
> -{
> -        /*
> -         * The file name is a variable length array.  Allocate the FTSENT
> -         * structure and the file name in one chunk.
> -         */
> -        size_t len = FLEXSIZEOF(FTSENT, fts_name, namelen + 1);
> -	register FTSENTRY *p;
> -#if !_LIBC
> -        p = malloc(len);
> -        if (p == NULL)
> -                return (NULL);
> -#else
> -	/*
> -	 * For glibc, we use a wrapper struct to provide the extra required
> -	 * fields without changing the FSENT layout.
> -	 */
> -	len += sizeof (struct FTSENT_wrapper);
> -	struct FTSENT_wrapper *wrapper = malloc(len);
> -	if (wrapper == NULL)
> -		return (NULL);
> -	p = &wrapper->ent;
> -        p->fts_statp = &wrapper->fts_stat;
> -#endif
> -
> -        /* Copy the name and guarantee NUL termination. */
> -        memcpy(p->fts_name, name, namelen);
> -        p->fts_name[namelen] = '\0';
> -
> -        p->fts_namelen = namelen;
> -        FTSENT_FTS(p)= sp;
> -        p->fts_path = sp->fts_path;
> -        p->fts_errno = 0;
> -        FTSENT_DIRP(p) = NULL;
> -        p->fts_flags = 0;
> -        p->fts_instr = FTS_NOINSTR;
> -        p->fts_number = 0;
> -        p->fts_pointer = NULL;
> -        return (p);
> -}
> -
> -static void
> -internal_function
> -fts_lfree (register FTSENTRY *head)
> -{
> -        int saved_errno = errno;
> -
> -        /* Free a linked list of structures. */
> -        register FTSENTRY *p;
> -        while ((p = head)) {
> -                head = head->fts_link;
> -                if (FTSENT_DIRP(p))
> -                        closedir (FTSENT_DIRP(p));
> -                free(FTSENT_WRAPPER(p));
> -        }
> -
> -        __set_errno (saved_errno);
> -}
> -
> -/*
> - * Allow essentially unlimited file name lengths; find, rm, ls should
> - * all work on any tree.  Most systems will allow creation of file
> - * names much longer than MAXPATHLEN, even though the kernel won't
> - * resolve them.  Add the size (not just what's needed) plus 256 bytes
> - * so don't realloc the file name 2 bytes at a time.
> - */
> -static bool
> -internal_function
> -fts_palloc (FTSOBJ *sp, size_t more)
> -{
> -        size_t new_len = sp->fts_pathlen + more + 256;
> -
> -        /*
> -         * See if fts_pathlen would overflow.
> -         */
> -        if (new_len < sp->fts_pathlen) {
> -                free(sp->fts_path);
> -                sp->fts_path = NULL;
> -                __set_errno (ENAMETOOLONG);
> -                return false;
> -        }
> -        sp->fts_pathlen = new_len;
> -        char *p = realloc(sp->fts_path, sp->fts_pathlen);
> -        if (p == NULL) {
> -                free(sp->fts_path);
> -                sp->fts_path = NULL;
> -                return false;
> -        }
> -        sp->fts_path = p;
> -        return true;
> -}
> -
> -/*
> - * When the file name is realloc'd, have to fix all of the pointers in
> - *  structures already returned.
> - */
> -static void
> -internal_function
> -fts_padjust (FTSOBJ *sp, FTSENTRY *head)
> -{
> -        char *addr = sp->fts_path;
> -
> -        /* This code looks at bit-patterns of freed pointers to
> -           relocate them, so it relies on undefined behavior.  If this
> -           trick does not work on your platform, please report a bug.  */
> -
> -#define ADJUST(p) do {                                                  \
> -        uintptr_t old_accpath = (uintptr_t) (p)->fts_accpath;           \
> -        if (old_accpath != (uintptr_t) (p)->fts_name) {                 \
> -                (p)->fts_accpath =                                      \
> -                  addr + (old_accpath - (uintptr_t) (p)->fts_path);     \
> -        }                                                               \
> -        (p)->fts_path = addr;                                           \
> -} while (0)
> -        /* Adjust the current set of children. */
> -        for (FTSENTRY *p = sp->fts_child; p; p = p->fts_link)
> -                ADJUST(p);
> -
> -        /* Adjust the rest of the tree, including the current level. */
> -        for (FTSENTRY *p = head; p->fts_level >= FTS_ROOTLEVEL;) {
> -                ADJUST(p);
> -                p = p->fts_link ? p->fts_link : p->fts_parent;
> -        }
> -}
> -
> -static size_t
> -internal_function _GL_ATTRIBUTE_PURE
> -fts_maxarglen (char * const *argv)
> -{
> -        size_t max;
> -
> -        for (max = 0; *argv; ++argv) {
> -                size_t len = strlen(*argv);
> -                if (len > max)
> -                        max = len;
> -        }
> -        return (max + 1);
> -}
> -
> -/*
> - * Change to dir specified by fd or file name without getting
> - * tricked by someone changing the world out from underneath us.
> - * Assumes p->fts_statp->st_dev and p->fts_statp->st_ino are filled in.
> - * If FD is non-negative, expect it to be used after this function returns,
> - * and to be closed eventually.  So don't pass e.g., 'dirfd(dirp)' and then
> - * do closedir(dirp), because that would invalidate the saved FD.
> - * Upon failure, close FD immediately and return nonzero.
> - */
> -static int
> -internal_function
> -fts_safe_changedir (FTSOBJ *sp, FTSENTRY *p, int fd, char const *dir)
> -{
> -        fts_assert (0 <= fd || dir != NULL);
> -        bool is_dotdot = dir && streq (dir, "..");
> -
> -        /* This clause handles the unusual case in which FTS_NOCHDIR
> -           is specified, along with FTS_CWDFD.  In that case, there is
> -           no need to change even the virtual cwd file descriptor.
> -           However, if FD is non-negative, we do close it here.  */
> -        if (ISSET (FTS_NOCHDIR))
> -          {
> -            if (ISSET (FTS_CWDFD) && 0 <= fd)
> -              close (fd);
> -            return 0;
> -          }
> -
> -        if (fd < 0 && is_dotdot && ISSET (FTS_CWDFD))
> -          {
> -            /* When possible, skip the diropen and subsequent fstat+dev/ino
> -               comparison.  I.e., when changing to parent directory
> -               (chdir ("..")), use a file descriptor from the ring and
> -               save the overhead of diropen+fstat, as well as avoiding
> -               failure when we lack "x" access to the virtual cwd.  */
> -            if ( ! i_ring_empty (&sp->fts_fd_ring))
> -              {
> -                int parent_fd;
> -                fd_ring_print (sp, stderr, "pre-pop");
> -                parent_fd = i_ring_pop (&sp->fts_fd_ring);
> -                if (0 <= parent_fd)
> -                  {
> -                    fd = parent_fd;
> -                    dir = NULL;
> -                  }
> -              }
> -          }
> -
> -        int newfd = fd;
> -        if (fd < 0 && (newfd = diropen (sp, dir)) < 0)
> -          return -1;
> -
> -        /* The following dev/inode check is necessary if we're doing a
> -           "logical" traversal (through symlinks, a la chown -L), if the
> -           system lacks O_NOFOLLOW support, or if we're changing to ".."
> -           (but not via a popped file descriptor).  When changing to the
> -           name "..", O_NOFOLLOW can't help.  In general, when the target is
> -           not "..", diropen's use of O_NOFOLLOW ensures we don't mistakenly
> -           follow a symlink, so we can avoid the expense of this fstat.  */
> -        int ret;
> -        if (ISSET(FTS_LOGICAL) || ! HAVE_WORKING_O_NOFOLLOW
> -            || (dir && streq (dir, "..")))
> -          {
> -            struct STRUCT_STAT sb;
> -            if (FSTAT (newfd, &sb))
> -              {
> -                ret = -1;
> -                goto bail;
> -              }
> -            if (p->fts_statp->st_dev != sb.st_dev
> -                || p->fts_statp->st_ino != sb.st_ino)
> -              {
> -                __set_errno (ENOENT);           /* disinformation */
> -                ret = -1;
> -                goto bail;
> -              }
> -          }
> -
> -        if (ISSET(FTS_CWDFD))
> -          {
> -            cwd_advance_fd (sp, newfd, ! is_dotdot);
> -            return 0;
> -          }
> -
> -        ret = fchdir(newfd);
> -bail:
> -        if (fd < 0)
> -          {
> -            int oerrno = errno;
> -            (void)close(newfd);
> -            __set_errno (oerrno);
> -          }
> -        return ret;
> -}
> diff --git a/io/fts64-time64.c b/io/fts64-time64.c
> index 6a1053194e..29f2dbc28c 100644
> --- a/io/fts64-time64.c
> +++ b/io/fts64-time64.c
> @@ -33,5 +33,5 @@
>  # define STRUCT_STATFS      statfs64
>  # define FSTATFS            __fstatfs64
>  
> -# include "fts.c"
> +# include "fts-common.c"
>  #endif
> diff --git a/io/fts64.c b/io/fts64.c
> index a6f607a873..1efa06ab3b 100644
> --- a/io/fts64.c
> +++ b/io/fts64.c
> @@ -16,11 +16,11 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -#define FTS_OPEN fts64_open
> -#define FTS_CLOSE fts64_close
> -#define FTS_READ fts64_read
> -#define FTS_SET fts64_set
> -#define FTS_CHILDREN fts64_children
> +#define FTS_OPEN __fts64_open
> +#define FTS_CLOSE __fts64_close
> +#define FTS_READ __fts64_read
> +#define FTS_SET __fts64_set
> +#define FTS_CHILDREN __fts64_children
>  #define FTSOBJ FTS64
>  #define FTSENTRY FTSENT64
>  #define INO_T ino64_t
> @@ -30,4 +30,30 @@
>  #define STRUCT_STATFS statfs64
>  #define FSTATFS __fstatfs64
>  
> -#include "fts.c"
> +#define fts_open __rename_fts_open
> +#define fts_close __rename_fts_close
> +#define fts_read __rename_fts_read
> +#define fts_set __rename_fts_set
> +#define fts_children __rename_fts_children
> +
> +#include "fts-common.c"
> +
> +#undef fts_open
> +#undef fts_close
> +#undef fts_read
> +#undef fts_set
> +#undef fts_children
> +
> +weak_alias (__fts64_open, fts64_open)
> +weak_alias (__fts64_close, fts64_close)
> +weak_alias (__fts64_read, fts64_read)
> +weak_alias (__fts64_set, fts64_set)
> +weak_alias (__fts64_children, fts64_children)
> +
> +#ifdef __OFF_T_MATCHES_OFF64_T
> +weak_alias (__fts64_open, fts_open)
> +weak_alias (__fts64_close, fts_close)
> +weak_alias (__fts64_read, fts_read)
> +weak_alias (__fts64_set, fts_set)
> +weak_alias (__fts64_children, fts_children)
> +#endif
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/fts.c b/sysdeps/unix/sysv/linux/mips/mips64/n64/fts.c
> deleted file mode 100644
> index d0c62e6195..0000000000
> --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/fts.c
> +++ /dev/null
> @@ -1 +0,0 @@
> -#include <io/fts.c>
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/fts64.c b/sysdeps/unix/sysv/linux/mips/mips64/n64/fts64.c
> deleted file mode 100644
> index 2472f8bf75..0000000000
> --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/fts64.c
> +++ /dev/null
> @@ -1 +0,0 @@
> -#include <io/fts64.c>
> diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/fts.c b/sysdeps/unix/sysv/linux/x86_64/x32/fts.c
> deleted file mode 100644
> index 980573ed68..0000000000
> --- a/sysdeps/unix/sysv/linux/x86_64/x32/fts.c
> +++ /dev/null
> @@ -1 +0,0 @@
> -#include <sysdeps/wordsize-64/fts.c>
> diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/fts64.c b/sysdeps/unix/sysv/linux/x86_64/x32/fts64.c
> deleted file mode 100644
> index 221d1b5608..0000000000
> --- a/sysdeps/unix/sysv/linux/x86_64/x32/fts64.c
> +++ /dev/null
> @@ -1 +0,0 @@
> -#include <sysdeps/wordsize-64/fts64.c>
> diff --git a/sysdeps/wordsize-64/fts.c b/sysdeps/wordsize-64/fts.c
> deleted file mode 100644
> index 159dc1febe..0000000000
> --- a/sysdeps/wordsize-64/fts.c
> +++ /dev/null
> @@ -1,19 +0,0 @@
> -#define fts64_open __rename_fts64_open
> -#define fts64_close __rename_fts64_close
> -#define fts64_read __rename_fts64_read
> -#define fts64_set __rename_fts64_set
> -#define fts64_children __rename_fts64_children
> -
> -#include "../../io/fts.c"
> -
> -#undef fts64_open
> -#undef fts64_close
> -#undef fts64_read
> -#undef fts64_set
> -#undef fts64_children
> -
> -weak_alias (fts_open, fts64_open)
> -weak_alias (fts_close, fts64_close)
> -weak_alias (fts_read, fts64_read)
> -weak_alias (fts_set, fts64_set)
> -weak_alias (fts_children, fts64_children)
> diff --git a/sysdeps/wordsize-64/fts64.c b/sysdeps/wordsize-64/fts64.c
> deleted file mode 100644
> index f2848fc3e4..0000000000
> --- a/sysdeps/wordsize-64/fts64.c
> +++ /dev/null
> @@ -1 +0,0 @@
> -/* Defined in fts.c.  */



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