1 /* Traverse a file hierarchy.
3 Copyright (C) 2004-2011 Free Software Foundation, Inc.
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 * Copyright (c) 1989, 1993
20 * The Regents of the University of California. All rights reserved.
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
25 * 1. Redistributions of source code must retain the above copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 4. Neither the name of the University nor the names of its contributors
31 * may be used to endorse or promote products derived from this software
32 * without specific prior written permission.
34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 * @(#)fts.h 8.3 (Berkeley) 8/14/94
53 # include <features.h>
60 # define __BEGIN_DECLS extern "C" {
61 # define __END_DECLS }
63 # define __BEGIN_DECLS
69 # include <sys/types.h>
70 # include <sys/stat.h>
74 struct _ftsent *fts_cur; /* current node */
75 struct _ftsent *fts_child; /* linked list of children */
76 struct _ftsent **fts_array; /* sort array */
77 dev_t fts_dev; /* starting device # */
78 char *fts_path; /* file name for this descent */
79 int fts_rfd; /* fd for root */
80 int fts_cwd_fd; /* the file descriptor on which the
81 virtual cwd is open, or AT_FDCWD */
82 size_t fts_pathlen; /* sizeof(path) */
83 size_t fts_nitems; /* elements in the sort array */
84 int (*fts_compar) (struct _ftsent const **, struct _ftsent const **);
87 # define FTS_COMFOLLOW 0x0001 /* follow command line symlinks */
88 # define FTS_LOGICAL 0x0002 /* logical walk */
89 # define FTS_NOCHDIR 0x0004 /* don't change directories */
90 # define FTS_NOSTAT 0x0008 /* don't get stat info */
91 # define FTS_PHYSICAL 0x0010 /* physical walk */
92 # define FTS_SEEDOT 0x0020 /* return dot and dot-dot */
93 # define FTS_XDEV 0x0040 /* don't cross devices */
94 # define FTS_WHITEOUT 0x0080 /* return whiteout information */
96 /* There are two ways to detect cycles.
97 The lazy way (which works only with FTS_PHYSICAL),
98 with which one may process a directory that is a
99 part of the cycle several times before detecting the cycle.
100 The `tight' way, whereby fts uses more memory (proportional
101 to number of `active' directories, aka distance from root
102 of current tree to current directory -- see active_dir_ht)
103 to detect any cycle right away. For example, du must use
104 this option to avoid counting disk space in a cycle multiple
105 times, but chown -R need not.
106 The default is to use the constant-memory lazy way, when possible
109 However, with FTS_LOGICAL (when following symlinks, e.g., chown -L)
110 using lazy cycle detection is inadequate. For example, traversing
111 a directory containing a symbolic link to a peer directory, it is
112 possible to encounter the same directory twice even though there
117 So, when FTS_LOGICAL is selected, we have to use a different
118 mode of cycle detection: FTS_TIGHT_CYCLE_CHECK. */
119 # define FTS_TIGHT_CYCLE_CHECK 0x0100
121 /* Use this flag to enable semantics with which the parent
122 application may be made both more efficient and more robust.
123 Whereas the default is to visit each directory in a recursive
124 traversal (via chdir), using this flag makes it so the initial
125 working directory is never changed. Instead, these functions
126 perform the traversal via a virtual working directory, maintained
127 through the file descriptor member, fts_cwd_fd. */
128 # define FTS_CWDFD 0x0200
130 /* Historically, for each directory that fts initially encounters, it would
131 open it, read all entries, and stat each entry, storing the results, and
132 then it would process the first entry. But that behavior is bad for
133 locality of reference, and also causes trouble with inode-simulating
134 file systems like FAT, CIFS, FUSE-based ones, etc., when entries from
135 their name/inode cache are flushed too early.
136 Use this flag to make fts_open and fts_read defer the stat/lstat/fststat
137 of each entry until it is actually processed. However, note that if you
138 use this option and also specify a comparison function, that function may
139 not examine any data via fts_statp. However, when fts_statp->st_mode is
140 nonzero, the S_IFMT type bits are valid, with mapped dirent.d_type data.
141 Of course, that happens only on file systems that provide useful
142 dirent.d_type data. */
143 # define FTS_DEFER_STAT 0x0400
145 # define FTS_NOATIME 0x0800 /* use O_NOATIME during traversal */
147 # define FTS_OPTIONMASK 0x0fff /* valid user option mask */
149 # define FTS_NAMEONLY 0x1000 /* (private) child names only */
150 # define FTS_STOP 0x2000 /* (private) unrecoverable error */
151 int fts_options; /* fts_open options, global flags */
153 /* Map a directory's device number to a boolean. The boolean is
154 true if for that file system (type determined by a single fstatfs
155 call per FS) st_nlink can be used to calculate the number of
156 sub-directory entries in a directory.
157 Using this table is an optimization that permits us to look up
158 file system type on a per-inode basis at the minimal cost of
159 calling fstatfs only once per traversed device. */
160 struct hash_table *fts_leaf_optimization_works_ht;
163 /* This data structure is used if FTS_TIGHT_CYCLE_CHECK is
164 specified. It records the directories between a starting
165 point and the current directory. I.e., a directory is
166 recorded here IFF we have visited it once, but we have not
167 yet completed processing of all its entries. Every time we
168 visit a new directory, we add that directory to this set.
169 When we finish with a directory (usually by visiting it a
170 second time), we remove it from this set. Each entry in
171 this data structure is a device/inode pair. This data
172 structure is used to detect directory cycles efficiently and
173 promptly even when the depth of a hierarchy is in the tens
175 struct hash_table *ht;
177 /* FIXME: rename these two members to have the fts_ prefix */
178 /* This data structure uses a lazy cycle-detection algorithm,
179 as done by rm via cycle-check.c. It's the default,
180 but it's not appropriate for programs like du. */
181 struct cycle_check_state *state;
184 /* A stack of the file descriptors corresponding to the
185 most-recently traversed parent directories.
186 Currently used only in FTS_CWDFD mode. */
190 typedef struct _ftsent {
191 struct _ftsent *fts_cycle; /* cycle node */
192 struct _ftsent *fts_parent; /* parent directory */
193 struct _ftsent *fts_link; /* next file in directory */
194 long fts_number; /* local numeric value */
195 void *fts_pointer; /* local address value */
196 char *fts_accpath; /* access file name */
197 char *fts_path; /* root name; == fts_fts->fts_path */
198 int fts_errno; /* errno for this node */
199 int fts_symfd; /* fd for symlink */
200 size_t fts_pathlen; /* strlen(fts_path) */
202 FTS *fts_fts; /* the file hierarchy itself */
204 # define FTS_ROOTPARENTLEVEL (-1)
205 # define FTS_ROOTLEVEL 0
206 ptrdiff_t fts_level; /* depth (-1 to N) */
208 size_t fts_namelen; /* strlen(fts_name) */
209 nlink_t fts_n_dirs_remaining; /* count down from st_nlink */
211 # define FTS_D 1 /* preorder directory */
212 # define FTS_DC 2 /* directory that causes cycles */
213 # define FTS_DEFAULT 3 /* none of the above */
214 # define FTS_DNR 4 /* unreadable directory */
215 # define FTS_DOT 5 /* dot or dot-dot */
216 # define FTS_DP 6 /* postorder directory */
217 # define FTS_ERR 7 /* error; errno is set */
218 # define FTS_F 8 /* regular file */
219 # define FTS_INIT 9 /* initialized only */
220 # define FTS_NS 10 /* stat(2) failed */
221 # define FTS_NSOK 11 /* no stat(2) requested */
222 # define FTS_SL 12 /* symbolic link */
223 # define FTS_SLNONE 13 /* symbolic link without target */
224 # define FTS_W 14 /* whiteout object */
225 unsigned short int fts_info; /* user flags for FTSENT structure */
227 # define FTS_DONTCHDIR 0x01 /* don't chdir .. to the parent */
228 # define FTS_SYMFOLLOW 0x02 /* followed a symlink to get here */
229 unsigned short int fts_flags; /* private flags for FTSENT structure */
231 # define FTS_AGAIN 1 /* read node again */
232 # define FTS_FOLLOW 2 /* follow symbolic link */
233 # define FTS_NOINSTR 3 /* no instructions */
234 # define FTS_SKIP 4 /* discard node */
235 unsigned short int fts_instr; /* fts_set() instructions */
237 struct stat fts_statp[1]; /* stat(2) information */
238 char fts_name[1]; /* file name */
241 #ifndef __GNUC_PREREQ
242 # if defined __GNUC__ && defined __GNUC_MINOR__
243 # define __GNUC_PREREQ(maj, min) \
244 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
246 # define __GNUC_PREREQ(maj, min) 0
250 #if __GNUC_PREREQ (3,4)
251 # undef __attribute_warn_unused_result__
252 # define __attribute_warn_unused_result__ \
253 __attribute__ ((__warn_unused_result__))
255 # define __attribute_warn_unused_result__ /* empty */
259 FTSENT *fts_children (FTS *, int) __THROW __attribute_warn_unused_result__;
260 int fts_close (FTS *) __THROW __attribute_warn_unused_result__;
261 FTS *fts_open (char * const *, int,
262 int (*)(const FTSENT **, const FTSENT **))
263 __THROW __attribute_warn_unused_result__;
264 FTSENT *fts_read (FTS *) __THROW __attribute_warn_unused_result__;
265 int fts_set (FTS *, FTSENT *, int) __THROW;