1 /*- 2 * Copyright (c) 2003-2007 Tim Kientzle 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 * $FreeBSD: src/usr.bin/tar/tree.h,v 1.4 2008/11/27 05:49:52 kientzle Exp $ 26 */ 27 28 /*- 29 * A set of routines for traversing directory trees. 30 * Similar in concept to the fts library, but with a few 31 * important differences: 32 * * Uses less memory. In particular, fts stores an entire directory 33 * in memory at a time. This package only keeps enough subdirectory 34 * information in memory to track the traversal. Information 35 * about non-directories is discarded as soon as possible. 36 * * Supports very deep logical traversals. The fts package 37 * uses "non-chdir" approach for logical traversals. This 38 * package does use a chdir approach for logical traversals 39 * and can therefore handle pathnames much longer than PATH_MAX. 40 * * Supports deep physical traversals "out of the box." 41 * Due to the memory optimizations above, there's no need to 42 * limit dir names to 32k. 43 */ 44 45 #include <sys/stat.h> 46 #include <stdio.h> 47 48 struct tree; 49 50 /* Initiate/terminate a tree traversal. */ 51 struct tree *tree_open(const char * /* pathname */); 52 void tree_close(struct tree *); 53 54 /* 55 * tree_next() returns Zero if there is no next entry, non-zero if 56 * there is. Note that directories are visited three times. 57 * Directories are always visited first as part of enumerating their 58 * parent; that is a "regular" visit. If tree_descend() is invoked at 59 * that time, the directory is added to a work list and will 60 * subsequently be visited two more times: once just after descending 61 * into the directory ("postdescent") and again just after ascending 62 * back to the parent ("postascent"). 63 * 64 * TREE_ERROR_DIR is returned if the descent failed (because the 65 * directory couldn't be opened, for instance). This is returned 66 * instead of TREE_POSTDESCENT/TREE_POSTASCENT. TREE_ERROR_DIR is not a 67 * fatal error, but it does imply that the relevant subtree won't be 68 * visited. TREE_ERROR_FATAL is returned for an error that left the 69 * traversal completely hosed. Right now, this is only returned for 70 * chdir() failures during ascent. 71 */ 72 #define TREE_REGULAR 1 73 #define TREE_POSTDESCENT 2 74 #define TREE_POSTASCENT 3 75 #define TREE_ERROR_DIR -1 76 #define TREE_ERROR_FATAL -2 77 78 int tree_next(struct tree *); 79 80 /* Errno value associated with the last traversal error. */ 81 int tree_errno(struct tree *); 82 83 /* 84 * Request that current entry be visited. If you invoke it on every 85 * directory, you'll get a physical traversal. This is ignored if the 86 * current entry isn't a directory or a link to a directory. So, if 87 * you invoke this on every returned path, you'll get a full logical 88 * traversal. 89 */ 90 void tree_descend(struct tree *); 91 92 /* 93 * Return information about the current entry. 94 */ 95 96 /* Current depth in the traversal. */ 97 int tree_current_depth(struct tree *); 98 99 /* 100 * The current full pathname, length of the full pathname, and a name 101 * that can be used to access the file. Because tree does use chdir 102 * extensively, the access path is almost never the same as the full 103 * current path. 104 * 105 * TODO: Flesh out this interface to provide other information. In 106 * particular, Windows can provide file size, mode, and some permission 107 * information without invoking stat() at all. 108 * 109 * TODO: On platforms that support it, use openat()-style operations 110 * to eliminate the chdir() operations entirely while still supporting 111 * arbitrarily deep traversals. This makes access_path troublesome to 112 * support, of course, which means we'll need a rich enough interface 113 * that clients can function without it. (In particular, we'll need 114 * tree_current_open() that returns an open file descriptor.) 115 * 116 * TODO: Provide tree_current_archive_entry(). 117 */ 118 const char *tree_current_path(struct tree *); 119 size_t tree_current_pathlen(struct tree *); 120 const char *tree_current_access_path(struct tree *); 121 122 /* 123 * Request the lstat() or stat() data for the current path. Since the 124 * tree package needs to do some of this anyway, and caches the 125 * results, you should take advantage of it here if you need it rather 126 * than make a redundant stat() or lstat() call of your own. 127 */ 128 const struct stat *tree_current_stat(struct tree *); 129 const struct stat *tree_current_lstat(struct tree *); 130 131 /* The following functions use tricks to avoid a certain number of 132 * stat()/lstat() calls. */ 133 /* "is_physical_dir" is equivalent to S_ISDIR(tree_current_lstat()->st_mode) */ 134 int tree_current_is_physical_dir(struct tree *); 135 /* "is_physical_link" is equivalent to S_ISLNK(tree_current_lstat()->st_mode) */ 136 int tree_current_is_physical_link(struct tree *); 137 /* "is_dir" is equivalent to S_ISDIR(tree_current_stat()->st_mode) */ 138 int tree_current_is_dir(struct tree *); 139 140 /* For testing/debugging: Dump the internal status to the given filehandle. */ 141 void tree_dump(struct tree *, FILE *); 142