272 lines
12 KiB
C
272 lines
12 KiB
C
/* Traverse a file hierarchy.
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Copyright (C) 2004-2022 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)fts.h 8.3 (Berkeley) 8/14/94
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*/
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#ifndef _FTS_H
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# define _FTS_H 1
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# ifdef _LIBC
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# include <features.h>
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# if __STDC_VERSION__ < 199901L
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# define __FLEXIBLE_ARRAY_MEMBER 1
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# else
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# define __FLEXIBLE_ARRAY_MEMBER
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# endif
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# else
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# define __FLEXIBLE_ARRAY_MEMBER FLEXIBLE_ARRAY_MEMBER
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# undef __THROW
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# define __THROW
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# undef __BEGIN_DECLS
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# undef __END_DECLS
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# ifdef __cplusplus
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# define __BEGIN_DECLS extern "C" {
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# define __END_DECLS }
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# else
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# define __BEGIN_DECLS
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# define __END_DECLS
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# endif
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# endif
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# include <stddef.h>
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# include <sys/types.h>
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# include <dirent.h>
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# include <sys/stat.h>
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# include "i-ring.h"
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typedef struct {
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struct _ftsent *fts_cur; /* current node */
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struct _ftsent *fts_child; /* linked list of children */
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struct _ftsent **fts_array; /* sort array */
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dev_t fts_dev; /* starting device # */
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char *fts_path; /* file name for this descent */
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int fts_rfd; /* fd for root */
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int fts_cwd_fd; /* the file descriptor on which the
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virtual cwd is open, or AT_FDCWD */
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size_t fts_pathlen; /* sizeof(path) */
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size_t fts_nitems; /* elements in the sort array */
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int (*fts_compar) (struct _ftsent const **, struct _ftsent const **);
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/* compare fn */
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# define FTS_COMFOLLOW 0x0001 /* follow command line symlinks */
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# define FTS_LOGICAL 0x0002 /* logical walk */
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# define FTS_NOCHDIR 0x0004 /* don't change directories */
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# define FTS_NOSTAT 0x0008 /* don't get stat info */
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# define FTS_PHYSICAL 0x0010 /* physical walk */
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# define FTS_SEEDOT 0x0020 /* return dot and dot-dot */
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# define FTS_XDEV 0x0040 /* don't cross devices */
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# define FTS_WHITEOUT 0x0080 /* return whiteout information */
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/* There are two ways to detect cycles.
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The lazy way (which works only with FTS_PHYSICAL),
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with which one may process a directory that is a
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part of the cycle several times before detecting the cycle.
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The "tight" way, whereby fts uses more memory (proportional
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to number of "active" directories, aka distance from root
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of current tree to current directory -- see active_dir_ht)
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to detect any cycle right away. For example, du must use
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this option to avoid counting disk space in a cycle multiple
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times, but chown -R need not.
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The default is to use the constant-memory lazy way, when possible
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(see below).
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However, with FTS_LOGICAL (when following symlinks, e.g., chown -L)
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using lazy cycle detection is inadequate. For example, traversing
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a directory containing a symbolic link to a peer directory, it is
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possible to encounter the same directory twice even though there
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is no cycle:
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dir
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...
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slink -> dir
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So, when FTS_LOGICAL is selected, we have to use a different
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mode of cycle detection: FTS_TIGHT_CYCLE_CHECK. */
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# define FTS_TIGHT_CYCLE_CHECK 0x0100
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/* Use this flag to enable semantics with which the parent
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application may be made both more efficient and more robust.
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Whereas the default is to visit each directory in a recursive
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traversal (via chdir), using this flag makes it so the initial
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working directory is never changed. Instead, these functions
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perform the traversal via a virtual working directory, maintained
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through the file descriptor member, fts_cwd_fd. */
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# define FTS_CWDFD 0x0200
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/* Historically, for each directory that fts initially encounters, it would
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open it, read all entries, and stat each entry, storing the results, and
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then it would process the first entry. But that behavior is bad for
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locality of reference, and also causes trouble with inode-simulating
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file systems like FAT, CIFS, FUSE-based ones, etc., when entries from
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their name/inode cache are flushed too early.
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Use this flag to make fts_open and fts_read defer the stat/lstat/fststat
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of each entry until it is actually processed. However, note that if you
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use this option and also specify a comparison function, that function may
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not examine any data via fts_statp. However, when fts_statp->st_mode is
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nonzero, the S_IFMT type bits are valid, with mapped dirent.d_type data.
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Of course, that happens only on file systems that provide useful
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dirent.d_type data. */
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# define FTS_DEFER_STAT 0x0400
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/* Use this flag to disable stripping of trailing slashes
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from input path names during fts_open initialization. */
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# define FTS_VERBATIM 0x0800
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# define FTS_OPTIONMASK 0x0fff /* valid user option mask */
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# define FTS_NAMEONLY 0x1000 /* (private) child names only */
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# define FTS_STOP 0x2000 /* (private) unrecoverable error */
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int fts_options; /* fts_open options, global flags */
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/* Map a directory's device number to a boolean. The boolean is
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true if for that file system (type determined by a single fstatfs
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call per FS) st_nlink can be used to calculate the number of
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sub-directory entries in a directory.
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Using this table is an optimization that permits us to look up
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file system type on a per-inode basis at the minimal cost of
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calling fstatfs only once per traversed device. */
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struct hash_table *fts_leaf_optimization_works_ht;
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union {
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/* This data structure is used if FTS_TIGHT_CYCLE_CHECK is
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specified. It records the directories between a starting
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point and the current directory. I.e., a directory is
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recorded here IFF we have visited it once, but we have not
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yet completed processing of all its entries. Every time we
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visit a new directory, we add that directory to this set.
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When we finish with a directory (usually by visiting it a
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second time), we remove it from this set. Each entry in
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this data structure is a device/inode pair. This data
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structure is used to detect directory cycles efficiently and
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promptly even when the depth of a hierarchy is in the tens
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of thousands. */
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struct hash_table *ht;
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/* FIXME: rename these two members to have the fts_ prefix */
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/* This data structure uses a lazy cycle-detection algorithm,
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as done by rm via cycle-check.c. It's the default,
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but it's not appropriate for programs like du. */
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struct cycle_check_state *state;
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} fts_cycle;
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/* A stack of the file descriptors corresponding to the
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most-recently traversed parent directories.
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Currently used only in FTS_CWDFD mode. */
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I_ring fts_fd_ring;
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} FTS;
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typedef struct _ftsent {
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struct _ftsent *fts_cycle; /* cycle node */
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struct _ftsent *fts_parent; /* parent directory */
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struct _ftsent *fts_link; /* next file in directory */
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DIR *fts_dirp; /* Dir pointer for any directory
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containing more entries than we
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read at one time. */
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long fts_number; /* local numeric value */
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void *fts_pointer; /* local address value */
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char *fts_accpath; /* access file name */
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char *fts_path; /* root name; == fts_fts->fts_path */
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int fts_errno; /* errno for this node */
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int fts_symfd; /* fd for symlink */
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size_t fts_pathlen; /* strlen(fts_path) */
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FTS *fts_fts; /* the file hierarchy itself */
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# define FTS_ROOTPARENTLEVEL (-1)
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# define FTS_ROOTLEVEL 0
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ptrdiff_t fts_level; /* depth (-1 to N) */
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size_t fts_namelen; /* strlen(fts_name) */
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# define FTS_D 1 /* preorder directory */
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# define FTS_DC 2 /* directory that causes cycles */
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# define FTS_DEFAULT 3 /* none of the above */
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# define FTS_DNR 4 /* unreadable directory */
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# define FTS_DOT 5 /* dot or dot-dot */
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# define FTS_DP 6 /* postorder directory */
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# define FTS_ERR 7 /* error; errno is set */
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# define FTS_F 8 /* regular file */
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# define FTS_INIT 9 /* initialized only */
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# define FTS_NS 10 /* stat(2) failed */
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# define FTS_NSOK 11 /* no stat(2) requested */
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# define FTS_SL 12 /* symbolic link */
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# define FTS_SLNONE 13 /* symbolic link without target */
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# define FTS_W 14 /* whiteout object */
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unsigned short int fts_info; /* user flags for FTSENT structure */
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# define FTS_DONTCHDIR 0x01 /* don't chdir .. to the parent */
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# define FTS_SYMFOLLOW 0x02 /* followed a symlink to get here */
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unsigned short int fts_flags; /* private flags for FTSENT structure */
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# define FTS_AGAIN 1 /* read node again */
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# define FTS_FOLLOW 2 /* follow symbolic link */
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# define FTS_NOINSTR 3 /* no instructions */
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# define FTS_SKIP 4 /* discard node */
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unsigned short int fts_instr; /* fts_set() instructions */
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struct stat fts_statp[1]; /* stat(2) information */
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char fts_name[__FLEXIBLE_ARRAY_MEMBER]; /* file name */
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} FTSENT;
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__BEGIN_DECLS
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_GL_ATTRIBUTE_NODISCARD
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FTSENT *fts_children (FTS *, int) __THROW;
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_GL_ATTRIBUTE_NODISCARD
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int fts_close (FTS *) __THROW;
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_GL_ATTRIBUTE_NODISCARD
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FTS *fts_open (char * const *, int,
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int (*)(const FTSENT **, const FTSENT **))
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_GL_ATTRIBUTE_DEALLOC (fts_close, 1) __THROW;
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_GL_ATTRIBUTE_NODISCARD
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FTSENT *fts_read (FTS *) __THROW;
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int fts_set (FTS *, FTSENT *, int) __THROW;
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__END_DECLS
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#endif /* fts.h */
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