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--- /dev/null
+++ b/lib/fts_.h
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+/* Traverse a file hierarchy.
+
+   Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/*
+ * Copyright (c) 1989, 1993
+ *	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.
+ *
+ *	@(#)fts.h	8.3 (Berkeley) 8/14/94
+ */
+
+#ifndef	_FTS_H
+# define _FTS_H 1
+
+# ifdef _LIBC
+#  include <features.h>
+# else
+#  undef __THROW
+#  define __THROW
+#  undef __BEGIN_DECLS
+#  define __BEGIN_DECLS
+#  undef __END_DECLS
+#  define __END_DECLS
+# endif
+
+# include <stddef.h>
+# include <sys/types.h>
+# include "hash.h"
+# include "cycle-check.h"
+
+typedef struct {
+	struct _ftsent *fts_cur;	/* current node */
+	struct _ftsent *fts_child;	/* linked list of children */
+	struct _ftsent **fts_array;	/* sort array */
+	dev_t fts_dev;			/* starting device # */
+	char *fts_path;			/* path for this descent */
+	int fts_rfd;			/* fd for root */
+	size_t fts_pathlen;		/* sizeof(path) */
+	size_t fts_nitems;			/* elements in the sort array */
+	int (*fts_compar) (struct _ftsent const **, struct _ftsent const **);
+					/* compare fn */
+
+# define FTS_COMFOLLOW	0x0001		/* follow command line symlinks */
+# define FTS_LOGICAL	0x0002		/* logical walk */
+# define FTS_NOCHDIR	0x0004		/* don't change directories */
+# define FTS_NOSTAT	0x0008		/* don't get stat info */
+# define FTS_PHYSICAL	0x0010		/* physical walk */
+# define FTS_SEEDOT	0x0020		/* return dot and dot-dot */
+# define FTS_XDEV	0x0040		/* don't cross devices */
+# define FTS_WHITEOUT	0x0080		/* return whiteout information */
+
+  /* There are two ways to detect cycles.
+     The lazy way, with which one may process a directory that is a
+     part of the cycle several times before detecting the cycle.
+     The `tight' way, whereby fts uses more memory (proportional
+     to number of `active' directories, aka distance from root
+     of current tree to current directory -- see active_dir_ht)
+     to detect any cycle right away.  For example, du must use
+     this option to avoid counting disk space in a cycle multiple
+     times, but chown -R need not.
+     The default is to use the constant-memory lazy way. */
+# define FTS_TIGHT_CYCLE_CHECK	0x0100
+
+# define FTS_OPTIONMASK	0x01ff		/* valid user option mask */
+
+# define FTS_NAMEONLY	0x1000		/* (private) child names only */
+# define FTS_STOP	0x2000		/* (private) unrecoverable error */
+	int fts_options;		/* fts_open options, global flags */
+
+	/* This data structure records the directories between a starting
+	   point and the current directory.  I.e., a directory is recorded
+	   here IFF we have visited it once, but we have not yet completed
+	   processing of all its entries.  Every time we visit a new directory,
+	   we add that directory to this set.  When we finish with a directory
+	   (usually by visiting it a second time), we remove it from this
+	   set.  Each entry in this data structure is a device/inode pair.
+	   This data structure is used to detect directory cycles efficiently
+	   and promptly even when the depth of a hierarchy is in the tens
+	   of thousands.  Lazy checking, as done by GNU rm via cycle-check.c,
+	   wouldn't be appropriate for du.  */
+	Hash_table *active_dir_ht;
+	struct cycle_check_state *cycle_state;
+} FTS;
+
+typedef struct _ftsent {
+	struct _ftsent *fts_cycle;	/* cycle node */
+	struct _ftsent *fts_parent;	/* parent directory */
+	struct _ftsent *fts_link;	/* next file in directory */
+	long fts_number;	        /* local numeric value */
+	void *fts_pointer;	        /* local address value */
+	char *fts_accpath;		/* access path */
+	char *fts_path;			/* root path; == fts_fts->fts_path */
+	int fts_errno;			/* errno for this node */
+	int fts_symfd;			/* fd for symlink */
+	size_t fts_pathlen;		/* strlen(fts_path) */
+
+	FTS *fts_fts;			/* the file hierarchy itself */
+
+# define FTS_ROOTPARENTLEVEL	(-1)
+# define FTS_ROOTLEVEL		 0
+	ptrdiff_t fts_level;		/* depth (-1 to N) */
+
+	size_t fts_namelen;		/* strlen(fts_name) */
+
+# define FTS_D		 1		/* preorder directory */
+# define FTS_DC		 2		/* directory that causes cycles */
+# define FTS_DEFAULT	 3		/* none of the above */
+# define FTS_DNR	 4		/* unreadable directory */
+# define FTS_DOT	 5		/* dot or dot-dot */
+# define FTS_DP		 6		/* postorder directory */
+# define FTS_ERR	 7		/* error; errno is set */
+# define FTS_F		 8		/* regular file */
+# define FTS_INIT	 9		/* initialized only */
+# define FTS_NS		10		/* stat(2) failed */
+# define FTS_NSOK	11		/* no stat(2) requested */
+# define FTS_SL		12		/* symbolic link */
+# define FTS_SLNONE	13		/* symbolic link without target */
+# define FTS_W		14		/* whiteout object */
+	unsigned short int fts_info;	/* user flags for FTSENT structure */
+
+# define FTS_DONTCHDIR	 0x01		/* don't chdir .. to the parent */
+# define FTS_SYMFOLLOW	 0x02		/* followed a symlink to get here */
+	unsigned short int fts_flags;	/* private flags for FTSENT structure */
+
+# define FTS_AGAIN	 1		/* read node again */
+# define FTS_FOLLOW	 2		/* follow symbolic link */
+# define FTS_NOINSTR	 3		/* no instructions */
+# define FTS_SKIP	 4		/* discard node */
+	unsigned short int fts_instr;	/* fts_set() instructions */
+
+	struct stat fts_statp[1];	/* stat(2) information */
+	char fts_name[1];		/* file name */
+} FTSENT;
+
+__BEGIN_DECLS
+FTSENT	*fts_children (FTS *, int) __THROW;
+int	 fts_close (FTS *) __THROW;
+FTS	*fts_open (char * const *, int,
+		   int (*)(const FTSENT **, const FTSENT **)) __THROW;
+FTSENT	*fts_read (FTS *) __THROW;
+int	 fts_set (FTS *, FTSENT *, int) __THROW;
+__END_DECLS
+
+#endif /* fts.h */