external/bsd/libarchive/dist/tar/tree.h

   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 *);