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fts_.h

/* 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>
#  define _LGPL_PACKAGE 1
# 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 <sys/stat.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;               /* file name 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 (which works only with FTS_PHYSICAL),
     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, when possible
     (see below).

     However, with FTS_LOGICAL (when following symlinks, e.g., chown -L)
     using lazy cycle detection is inadequate.  For example, traversing
     a directory containing a symbolic link to a peer directory, it is
     possible to encounter the same directory twice even though there
     is no cycle:
     dir
     ...
     slink -> dir
     So, when FTS_LOGICAL is selected, we have to use a different
     mode of cycle detection: FTS_TIGHT_CYCLE_CHECK.  */
# 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 */

# if !_LGPL_PACKAGE
      union {
            /* This data structure is used if FTS_TIGHT_CYCLE_CHECK is
               specified.  It 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.  */
            struct hash_table *ht;

            /* This data structure uses lazy checking, as done by rm via
                 cycle-check.c.  It's the default, but it's not appropriate
                 for programs like du.  */
            struct cycle_check_state *state;
      } fts_cycle;
# endif
} 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 file name */
      char *fts_path;               /* root name; == 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 */

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