1 /* Traverse a file hierarchy.
3 Copyright (C) 2004-2010 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.
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23 * modification, are permitted provided that the following conditions
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46 * @(#)fts.h 8.3 (Berkeley) 8/14/94
53 # include <features.h>
58 # define __BEGIN_DECLS
64 # include <sys/types.h>
65 # include <sys/stat.h>
69 struct _ftsent *fts_cur; /* current node */
70 struct _ftsent *fts_child; /* linked list of children */
71 struct _ftsent **fts_array; /* sort array */
72 dev_t fts_dev; /* starting device # */
73 char *fts_path; /* file name for this descent */
74 int fts_rfd; /* fd for root */
75 int fts_cwd_fd; /* the file descriptor on which the
76 virtual cwd is open, or AT_FDCWD */
77 size_t fts_pathlen; /* sizeof(path) */
78 size_t fts_nitems; /* elements in the sort array */
79 int (*fts_compar) (struct _ftsent const **, struct _ftsent const **);
82 # define FTS_COMFOLLOW 0x0001 /* follow command line symlinks */
83 # define FTS_LOGICAL 0x0002 /* logical walk */
84 # define FTS_NOCHDIR 0x0004 /* don't change directories */
85 # define FTS_NOSTAT 0x0008 /* don't get stat info */
86 # define FTS_PHYSICAL 0x0010 /* physical walk */
87 # define FTS_SEEDOT 0x0020 /* return dot and dot-dot */
88 # define FTS_XDEV 0x0040 /* don't cross devices */
89 # define FTS_WHITEOUT 0x0080 /* return whiteout information */
91 /* There are two ways to detect cycles.
92 The lazy way (which works only with FTS_PHYSICAL),
93 with which one may process a directory that is a
94 part of the cycle several times before detecting the cycle.
95 The `tight' way, whereby fts uses more memory (proportional
96 to number of `active' directories, aka distance from root
97 of current tree to current directory -- see active_dir_ht)
98 to detect any cycle right away. For example, du must use
99 this option to avoid counting disk space in a cycle multiple
100 times, but chown -R need not.
101 The default is to use the constant-memory lazy way, when possible
104 However, with FTS_LOGICAL (when following symlinks, e.g., chown -L)
105 using lazy cycle detection is inadequate. For example, traversing
106 a directory containing a symbolic link to a peer directory, it is
107 possible to encounter the same directory twice even though there
112 So, when FTS_LOGICAL is selected, we have to use a different
113 mode of cycle detection: FTS_TIGHT_CYCLE_CHECK. */
114 # define FTS_TIGHT_CYCLE_CHECK 0x0100
116 /* Use this flag to enable semantics with which the parent
117 application may be made both more efficient and more robust.
118 Whereas the default is to visit each directory in a recursive
119 traversal (via chdir), using this flag makes it so the initial
120 working directory is never changed. Instead, these functions
121 perform the traversal via a virtual working directory, maintained
122 through the file descriptor member, fts_cwd_fd. */
123 # define FTS_CWDFD 0x0200
125 /* Historically, for each directory that fts initially encounters, it would
126 open it, read all entries, and stat each entry, storing the results, and
127 then it would process the first entry. But that behavior is bad for
128 locality of reference, and also causes trouble with inode-simulating
129 file systems like FAT, CIFS, FUSE-based ones, etc., when entries from
130 their name/inode cache are flushed too early.
131 Use this flag to make fts_open and fts_read defer the stat/lstat/fststat
132 of each entry until it is actually processed. However, note that if you
133 use this option and also specify a comparison function, that function may
134 not examine any data via fts_statp. However, when fts_statp->st_mode is
135 nonzero, the S_IFMT type bits are valid, with mapped dirent.d_type data.
136 Of course, that happens only on file systems that provide useful
137 dirent.d_type data. */
138 # define FTS_DEFER_STAT 0x0400
140 # define FTS_OPTIONMASK 0x07ff /* valid user option mask */
142 # define FTS_NAMEONLY 0x1000 /* (private) child names only */
143 # define FTS_STOP 0x2000 /* (private) unrecoverable error */
144 int fts_options; /* fts_open options, global flags */
146 /* Map a directory's device number to a boolean. The boolean is
147 true if for that file system (type determined by a single fstatfs
148 call per FS) st_nlink can be used to calculate the number of
149 sub-directory entries in a directory.
150 Using this table is an optimization that permits us to look up
151 file system type on a per-inode basis at the minimal cost of
152 calling fstatfs only once per traversed device. */
153 struct hash_table *fts_leaf_optimization_works_ht;
156 /* This data structure is used if FTS_TIGHT_CYCLE_CHECK is
157 specified. It records the directories between a starting
158 point and the current directory. I.e., a directory is
159 recorded here IFF we have visited it once, but we have not
160 yet completed processing of all its entries. Every time we
161 visit a new directory, we add that directory to this set.
162 When we finish with a directory (usually by visiting it a
163 second time), we remove it from this set. Each entry in
164 this data structure is a device/inode pair. This data
165 structure is used to detect directory cycles efficiently and
166 promptly even when the depth of a hierarchy is in the tens
168 struct hash_table *ht;
170 /* FIXME: rename these two members to have the fts_ prefix */
171 /* This data structure uses a lazy cycle-detection algorithm,
172 as done by rm via cycle-check.c. It's the default,
173 but it's not appropriate for programs like du. */
174 struct cycle_check_state *state;
177 /* A stack of the file descriptors corresponding to the
178 most-recently traversed parent directories.
179 Currently used only in FTS_CWDFD mode. */
183 typedef struct _ftsent {
184 struct _ftsent *fts_cycle; /* cycle node */
185 struct _ftsent *fts_parent; /* parent directory */
186 struct _ftsent *fts_link; /* next file in directory */
187 long fts_number; /* local numeric value */
188 void *fts_pointer; /* local address value */
189 char *fts_accpath; /* access file name */
190 char *fts_path; /* root name; == fts_fts->fts_path */
191 int fts_errno; /* errno for this node */
192 int fts_symfd; /* fd for symlink */
193 size_t fts_pathlen; /* strlen(fts_path) */
195 FTS *fts_fts; /* the file hierarchy itself */
197 # define FTS_ROOTPARENTLEVEL (-1)
198 # define FTS_ROOTLEVEL 0
199 ptrdiff_t fts_level; /* depth (-1 to N) */
201 size_t fts_namelen; /* strlen(fts_name) */
202 nlink_t fts_n_dirs_remaining; /* count down from st_nlink */
204 # define FTS_D 1 /* preorder directory */
205 # define FTS_DC 2 /* directory that causes cycles */
206 # define FTS_DEFAULT 3 /* none of the above */
207 # define FTS_DNR 4 /* unreadable directory */
208 # define FTS_DOT 5 /* dot or dot-dot */
209 # define FTS_DP 6 /* postorder directory */
210 # define FTS_ERR 7 /* error; errno is set */
211 # define FTS_F 8 /* regular file */
212 # define FTS_INIT 9 /* initialized only */
213 # define FTS_NS 10 /* stat(2) failed */
214 # define FTS_NSOK 11 /* no stat(2) requested */
215 # define FTS_SL 12 /* symbolic link */
216 # define FTS_SLNONE 13 /* symbolic link without target */
217 # define FTS_W 14 /* whiteout object */
218 unsigned short int fts_info; /* user flags for FTSENT structure */
220 # define FTS_DONTCHDIR 0x01 /* don't chdir .. to the parent */
221 # define FTS_SYMFOLLOW 0x02 /* followed a symlink to get here */
222 unsigned short int fts_flags; /* private flags for FTSENT structure */
224 # define FTS_AGAIN 1 /* read node again */
225 # define FTS_FOLLOW 2 /* follow symbolic link */
226 # define FTS_NOINSTR 3 /* no instructions */
227 # define FTS_SKIP 4 /* discard node */
228 unsigned short int fts_instr; /* fts_set() instructions */
230 struct stat fts_statp[1]; /* stat(2) information */
231 char fts_name[1]; /* file name */
234 #ifndef __GNUC_PREREQ
235 # if defined __GNUC__ && defined __GNUC_MINOR__
236 # define __GNUC_PREREQ(maj, min) \
237 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
239 # define __GNUC_PREREQ(maj, min) 0
243 #if __GNUC_PREREQ (3,4)
244 # undef __attribute_warn_unused_result__
245 # define __attribute_warn_unused_result__ \
246 __attribute__ ((__warn_unused_result__))
248 # define __attribute_warn_unused_result__ /* empty */
252 FTSENT *fts_children (FTS *, int) __THROW __attribute_warn_unused_result__;
253 int fts_close (FTS *) __THROW __attribute_warn_unused_result__;
254 FTS *fts_open (char * const *, int,
255 int (*)(const FTSENT **, const FTSENT **))
256 __THROW __attribute_warn_unused_result__;
257 FTSENT *fts_read (FTS *) __THROW __attribute_warn_unused_result__;
258 int fts_set (FTS *, FTSENT *, int) __THROW;