1 /* Traverse a file hierarchy. 2 3 Copyright (C) 2004-2012 Free Software Foundation, Inc. 4 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. 9 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. 14 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/>. */ 17 18 /* 19 * Copyright (c) 1989, 1993 20 * The Regents of the University of California. All rights reserved. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 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. 33 * 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 44 * SUCH DAMAGE. 45 * 46 * @(#)fts.h 8.3 (Berkeley) 8/14/94 47 */ 48 49 #ifndef _FTS_H 50 # define _FTS_H 1 51 52 # ifdef _LIBC 53 # include <features.h> 54 # else 55 # undef __THROW 56 # define __THROW 57 # undef __BEGIN_DECLS 58 # undef __END_DECLS 59 # ifdef __cplusplus 60 # define __BEGIN_DECLS extern "C" { 61 # define __END_DECLS } 62 # else 63 # define __BEGIN_DECLS 64 # define __END_DECLS 65 # endif 66 # endif 67 68 # include <stddef.h> 69 # include <sys/types.h> 70 # include <dirent.h> 71 # include <sys/stat.h> 72 # include "i-ring.h" 73 74 typedef struct { 75 struct _ftsent *fts_cur; /* current node */ 76 struct _ftsent *fts_child; /* linked list of children */ 77 struct _ftsent **fts_array; /* sort array */ 78 dev_t fts_dev; /* starting device # */ 79 char *fts_path; /* file name for this descent */ 80 int fts_rfd; /* fd for root */ 81 int fts_cwd_fd; /* the file descriptor on which the 82 virtual cwd is open, or AT_FDCWD */ 83 size_t fts_pathlen; /* sizeof(path) */ 84 size_t fts_nitems; /* elements in the sort array */ 85 int (*fts_compar) (struct _ftsent const **, struct _ftsent const **); 86 /* compare fn */ 87 88 # define FTS_COMFOLLOW 0x0001 /* follow command line symlinks */ 89 # define FTS_LOGICAL 0x0002 /* logical walk */ 90 # define FTS_NOCHDIR 0x0004 /* don't change directories */ 91 # define FTS_NOSTAT 0x0008 /* don't get stat info */ 92 # define FTS_PHYSICAL 0x0010 /* physical walk */ 93 # define FTS_SEEDOT 0x0020 /* return dot and dot-dot */ 94 # define FTS_XDEV 0x0040 /* don't cross devices */ 95 # define FTS_WHITEOUT 0x0080 /* return whiteout information */ 96 97 /* There are two ways to detect cycles. 98 The lazy way (which works only with FTS_PHYSICAL), 99 with which one may process a directory that is a 100 part of the cycle several times before detecting the cycle. 101 The "tight" way, whereby fts uses more memory (proportional 102 to number of "active" directories, aka distance from root 103 of current tree to current directory -- see active_dir_ht) 104 to detect any cycle right away. For example, du must use 105 this option to avoid counting disk space in a cycle multiple 106 times, but chown -R need not. 107 The default is to use the constant-memory lazy way, when possible 108 (see below). 109 110 However, with FTS_LOGICAL (when following symlinks, e.g., chown -L) 111 using lazy cycle detection is inadequate. For example, traversing 112 a directory containing a symbolic link to a peer directory, it is 113 possible to encounter the same directory twice even though there 114 is no cycle: 115 dir 116 ... 117 slink -> dir 118 So, when FTS_LOGICAL is selected, we have to use a different 119 mode of cycle detection: FTS_TIGHT_CYCLE_CHECK. */ 120 # define FTS_TIGHT_CYCLE_CHECK 0x0100 121 122 /* Use this flag to enable semantics with which the parent 123 application may be made both more efficient and more robust. 124 Whereas the default is to visit each directory in a recursive 125 traversal (via chdir), using this flag makes it so the initial 126 working directory is never changed. Instead, these functions 127 perform the traversal via a virtual working directory, maintained 128 through the file descriptor member, fts_cwd_fd. */ 129 # define FTS_CWDFD 0x0200 130 131 /* Historically, for each directory that fts initially encounters, it would 132 open it, read all entries, and stat each entry, storing the results, and 133 then it would process the first entry. But that behavior is bad for 134 locality of reference, and also causes trouble with inode-simulating 135 file systems like FAT, CIFS, FUSE-based ones, etc., when entries from 136 their name/inode cache are flushed too early. 137 Use this flag to make fts_open and fts_read defer the stat/lstat/fststat 138 of each entry until it is actually processed. However, note that if you 139 use this option and also specify a comparison function, that function may 140 not examine any data via fts_statp. However, when fts_statp->st_mode is 141 nonzero, the S_IFMT type bits are valid, with mapped dirent.d_type data. 142 Of course, that happens only on file systems that provide useful 143 dirent.d_type data. */ 144 # define FTS_DEFER_STAT 0x0400 145 146 # define FTS_NOATIME 0x0800 /* use O_NOATIME during traversal */ 147 148 # define FTS_OPTIONMASK 0x0fff /* valid user option mask */ 149 150 # define FTS_NAMEONLY 0x1000 /* (private) child names only */ 151 # define FTS_STOP 0x2000 /* (private) unrecoverable error */ 152 int fts_options; /* fts_open options, global flags */ 153 154 /* Map a directory's device number to a boolean. The boolean is 155 true if for that file system (type determined by a single fstatfs 156 call per FS) st_nlink can be used to calculate the number of 157 sub-directory entries in a directory. 158 Using this table is an optimization that permits us to look up 159 file system type on a per-inode basis at the minimal cost of 160 calling fstatfs only once per traversed device. */ 161 struct hash_table *fts_leaf_optimization_works_ht; 162 163 union { 164 /* This data structure is used if FTS_TIGHT_CYCLE_CHECK is 165 specified. It records the directories between a starting 166 point and the current directory. I.e., a directory is 167 recorded here IFF we have visited it once, but we have not 168 yet completed processing of all its entries. Every time we 169 visit a new directory, we add that directory to this set. 170 When we finish with a directory (usually by visiting it a 171 second time), we remove it from this set. Each entry in 172 this data structure is a device/inode pair. This data 173 structure is used to detect directory cycles efficiently and 174 promptly even when the depth of a hierarchy is in the tens 175 of thousands. */ 176 struct hash_table *ht; 177 178 /* FIXME: rename these two members to have the fts_ prefix */ 179 /* This data structure uses a lazy cycle-detection algorithm, 180 as done by rm via cycle-check.c. It's the default, 181 but it's not appropriate for programs like du. */ 182 struct cycle_check_state *state; 183 } fts_cycle; 184 185 /* A stack of the file descriptors corresponding to the 186 most-recently traversed parent directories. 187 Currently used only in FTS_CWDFD mode. */ 188 I_ring fts_fd_ring; 189 } FTS; 190 191 typedef struct _ftsent { 192 struct _ftsent *fts_cycle; /* cycle node */ 193 struct _ftsent *fts_parent; /* parent directory */ 194 struct _ftsent *fts_link; /* next file in directory */ 195 DIR *fts_dirp; /* Dir pointer for any directory 196 containing more entries than we 197 read at one time. */ 198 long fts_number; /* local numeric value */ 199 void *fts_pointer; /* local address value */ 200 char *fts_accpath; /* access file name */ 201 char *fts_path; /* root name; == fts_fts->fts_path */ 202 int fts_errno; /* errno for this node */ 203 int fts_symfd; /* fd for symlink */ 204 size_t fts_pathlen; /* strlen(fts_path) */ 205 206 FTS *fts_fts; /* the file hierarchy itself */ 207 208 # define FTS_ROOTPARENTLEVEL (-1) 209 # define FTS_ROOTLEVEL 0 210 ptrdiff_t fts_level; /* depth (-1 to N) */ 211 212 size_t fts_namelen; /* strlen(fts_name) */ 213 nlink_t fts_n_dirs_remaining; /* count down from st_nlink */ 214 215 # define FTS_D 1 /* preorder directory */ 216 # define FTS_DC 2 /* directory that causes cycles */ 217 # define FTS_DEFAULT 3 /* none of the above */ 218 # define FTS_DNR 4 /* unreadable directory */ 219 # define FTS_DOT 5 /* dot or dot-dot */ 220 # define FTS_DP 6 /* postorder directory */ 221 # define FTS_ERR 7 /* error; errno is set */ 222 # define FTS_F 8 /* regular file */ 223 # define FTS_INIT 9 /* initialized only */ 224 # define FTS_NS 10 /* stat(2) failed */ 225 # define FTS_NSOK 11 /* no stat(2) requested */ 226 # define FTS_SL 12 /* symbolic link */ 227 # define FTS_SLNONE 13 /* symbolic link without target */ 228 # define FTS_W 14 /* whiteout object */ 229 unsigned short int fts_info; /* user flags for FTSENT structure */ 230 231 # define FTS_DONTCHDIR 0x01 /* don't chdir .. to the parent */ 232 # define FTS_SYMFOLLOW 0x02 /* followed a symlink to get here */ 233 unsigned short int fts_flags; /* private flags for FTSENT structure */ 234 235 # define FTS_AGAIN 1 /* read node again */ 236 # define FTS_FOLLOW 2 /* follow symbolic link */ 237 # define FTS_NOINSTR 3 /* no instructions */ 238 # define FTS_SKIP 4 /* discard node */ 239 unsigned short int fts_instr; /* fts_set() instructions */ 240 241 struct stat fts_statp[1]; /* stat(2) information */ 242 char fts_name[1]; /* file name */ 243 } FTSENT; 244 245 #ifndef __GNUC_PREREQ 246 # if defined __GNUC__ && defined __GNUC_MINOR__ 247 # define __GNUC_PREREQ(maj, min) \ 248 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) 249 # else 250 # define __GNUC_PREREQ(maj, min) 0 251 # endif 252 #endif 253 254 #if __GNUC_PREREQ (3,4) 255 # undef __attribute_warn_unused_result__ 256 # define __attribute_warn_unused_result__ \ 257 __attribute__ ((__warn_unused_result__)) 258 #else 259 # define __attribute_warn_unused_result__ /* empty */ 260 #endif 261 262 __BEGIN_DECLS 263 FTSENT *fts_children (FTS *, int) __THROW __attribute_warn_unused_result__; 264 int fts_close (FTS *) __THROW __attribute_warn_unused_result__; 265 FTS *fts_open (char * const *, int, 266 int (*)(const FTSENT **, const FTSENT **)) 267 __THROW __attribute_warn_unused_result__; 268 FTSENT *fts_read (FTS *) __THROW __attribute_warn_unused_result__; 269 int fts_set (FTS *, FTSENT *, int) __THROW; 270 __END_DECLS 271 272 #endif /* fts.h */ 273