summaryrefslogtreecommitdiffstats
path: root/contrib/libarchive/tar/tree.h
blob: 9a7e0d30744f63a99eae9920db3b37d01f4707d9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
/*-
 * Copyright (c) 2003-2007 Tim Kientzle
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $FreeBSD: src/usr.bin/tar/tree.h,v 1.4 2008/11/27 05:49:52 kientzle Exp $
 */

/*-
 * A set of routines for traversing directory trees.
 * Similar in concept to the fts library, but with a few
 * important differences:
 *    * Uses less memory.  In particular, fts stores an entire directory
 *      in memory at a time.  This package only keeps enough subdirectory
 *      information in memory to track the traversal.  Information
 *      about non-directories is discarded as soon as possible.
 *    * Supports very deep logical traversals.  The fts package
 *      uses "non-chdir" approach for logical traversals.  This
 *      package does use a chdir approach for logical traversals
 *      and can therefore handle pathnames much longer than PATH_MAX.
 *    * Supports deep physical traversals "out of the box."
 *      Due to the memory optimizations above, there's no need to
 *      limit dir names to 32k.
 */

#include <sys/stat.h>
#include <stdio.h>

struct tree;

/* Initiate/terminate a tree traversal. */
struct tree *tree_open(const char * /* pathname */);
void tree_close(struct tree *);

/*
 * tree_next() returns Zero if there is no next entry, non-zero if
 * there is.  Note that directories are visited three times.
 * Directories are always visited first as part of enumerating their
 * parent; that is a "regular" visit.  If tree_descend() is invoked at
 * that time, the directory is added to a work list and will
 * subsequently be visited two more times: once just after descending
 * into the directory ("postdescent") and again just after ascending
 * back to the parent ("postascent").
 *
 * TREE_ERROR_DIR is returned if the descent failed (because the
 * directory couldn't be opened, for instance).  This is returned
 * instead of TREE_POSTDESCENT/TREE_POSTASCENT.  TREE_ERROR_DIR is not a
 * fatal error, but it does imply that the relevant subtree won't be
 * visited.  TREE_ERROR_FATAL is returned for an error that left the
 * traversal completely hosed.  Right now, this is only returned for
 * chdir() failures during ascent.
 */
#define	TREE_REGULAR	1
#define	TREE_POSTDESCENT	2
#define	TREE_POSTASCENT	3
#define	TREE_ERROR_DIR	-1
#define	TREE_ERROR_FATAL -2

int tree_next(struct tree *);

/* Errno value associated with the last traversal error. */
int tree_errno(struct tree *);

/*
 * Request that current entry be visited.  If you invoke it on every
 * directory, you'll get a physical traversal.  This is ignored if the
 * current entry isn't a directory or a link to a directory.  So, if
 * you invoke this on every returned path, you'll get a full logical
 * traversal.
 */
void tree_descend(struct tree *);

/*
 * Return information about the current entry.
 */

/* Current depth in the traversal. */
int tree_current_depth(struct tree *);

/*
 * The current full pathname, length of the full pathname, and a name
 * that can be used to access the file.  Because tree does use chdir
 * extensively, the access path is almost never the same as the full
 * current path.
 *
 * TODO: Flesh out this interface to provide other information.  In
 * particular, Windows can provide file size, mode, and some permission
 * information without invoking stat() at all.
 *
 * TODO: On platforms that support it, use openat()-style operations
 * to eliminate the chdir() operations entirely while still supporting
 * arbitrarily deep traversals.  This makes access_path troublesome to
 * support, of course, which means we'll need a rich enough interface
 * that clients can function without it.  (In particular, we'll need
 * tree_current_open() that returns an open file descriptor.)
 *
 * TODO: Provide tree_current_archive_entry().
 */
const char *tree_current_path(struct tree *);
size_t tree_current_pathlen(struct tree *);
const char *tree_current_access_path(struct tree *);

/*
 * Request the lstat() or stat() data for the current path.  Since the
 * tree package needs to do some of this anyway, and caches the
 * results, you should take advantage of it here if you need it rather
 * than make a redundant stat() or lstat() call of your own.
 */
const struct stat *tree_current_stat(struct tree *);
const struct stat *tree_current_lstat(struct tree *);

/* The following functions use tricks to avoid a certain number of
 * stat()/lstat() calls. */
/* "is_physical_dir" is equivalent to S_ISDIR(tree_current_lstat()->st_mode) */
int tree_current_is_physical_dir(struct tree *);
/* "is_physical_link" is equivalent to S_ISLNK(tree_current_lstat()->st_mode) */
int tree_current_is_physical_link(struct tree *);
/* "is_dir" is equivalent to S_ISDIR(tree_current_stat()->st_mode) */
int tree_current_is_dir(struct tree *);

/* For testing/debugging: Dump the internal status to the given filehandle. */
void tree_dump(struct tree *, FILE *);
OpenPOWER on IntegriCloud