/* Traverse a file hierarchy.
- Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007 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
# include <stddef.h>
# include <sys/types.h>
-# include "hash.h"
-# include "cycle-check.h"
+# include <sys/stat.h>
+# include "i-ring.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; /* path for this descent */
+ char *fts_path; /* file name for this descent */
int fts_rfd; /* fd for root */
+ int fts_cwd_fd; /* the file descriptor on which the
+ virtual cwd is open, or AT_FDCWD */
size_t fts_pathlen; /* sizeof(path) */
- size_t fts_nitems; /* elements in the sort array */
+ size_t fts_nitems; /* elements in the sort array */
int (*fts_compar) (struct _ftsent const **, struct _ftsent const **);
/* compare fn */
# define FTS_WHITEOUT 0x0080 /* return whiteout information */
/* There are two ways to detect cycles.
- The lazy way, with which one may process a directory that is a
+ 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
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. */
+ 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 */
+ /* Use this flag to enable semantics with which the parent
+ application may be made both more efficient and more robust.
+ Whereas the default is to visit each directory in a recursive
+ traversal (via chdir), using this flag makes it so the initial
+ working directory is never changed. Instead, these functions
+ perform the traversal via a virtual working directory, maintained
+ through the file descriptor member, fts_cwd_fd. */
+# define FTS_CWDFD 0x0200
+
+ /* Historically, for each directory that fts initially encounters, it would
+ open it, read all entries, and stat each entry, storing the results, and
+ then it would process the first entry. But that behavior is bad for
+ locality of reference, and also causes trouble with inode-simulating
+ file systems like FAT, CIFS, FUSE-based ones, etc., when entries from
+ their name/inode cache are flushed too early.
+ Use this flag to make fts_open and fts_read defer the stat/lstat/fststat
+ of each entry until it actually processed. However, note that if you use
+ this option and also specify a comparison function, that function may not
+ examine any data via fts_statp. */
+# define FTS_DEFER_STAT 0x0400
+
+# define FTS_OPTIONMASK 0x07ff /* 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 */
- /* This data structure 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. Lazy checking, as done by GNU rm via cycle-check.c,
- wouldn't be appropriate for du. */
- Hash_table *active_dir_ht;
- struct cycle_check_state *cycle_state;
+# if GNULIB_FTS
+ 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;
+
+ /* FIXME: rename these two members to have the fts_ prefix */
+ /* This data structure uses a lazy cycle-detection algorithm,
+ 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
+ /* A stack of the file descriptors corresponding to the
+ most-recently traversed parent directories.
+ Currently used only in FTS_CWDFD mode. */
+ I_ring fts_fd_ring;
} FTS;
typedef struct _ftsent {
struct _ftsent *fts_link; /* next file in directory */
long fts_number; /* local numeric value */
void *fts_pointer; /* local address value */
- char *fts_accpath; /* access path */
- char *fts_path; /* root path; == fts_fts->fts_path */
+ 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) */
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