1 .\" Copyright (c) 2003-2007 Tim Kientzle
2 .\" All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
13 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 .\" $FreeBSD: src/lib/libarchive/libarchive.3,v 1.11 2007/01/09 08:05:56 kientzle Exp $
32 .Nd functions for reading and writing streaming archives
38 library provides a flexible interface for reading and writing
39 archives in various formats such as tar and cpio.
41 also supports reading and writing archives compressed using
42 various compression filters such as gzip and bzip2.
43 The library is inherently stream-oriented; readers serially iterate through
44 the archive, writers serially add things to the archive.
45 In particular, note that there is currently no built-in support for
46 random access nor for in-place modification.
48 When reading an archive, the library automatically detects the
49 format and the compression.
50 The library currently has read support for:
53 old-style tar archives,
55 most variants of the POSIX
63 GNU-format tar archives,
65 most common cpio archive formats,
67 ISO9660 CD images (including RockRidge and Joliet extensions),
71 The library automatically detects archives compressed with
77 and decompresses them transparently.
79 When writing an archive, you can specify the compression
80 to be used and the format to use.
89 .Dq pax interchange format
92 POSIX octet-oriented cpio archives,
96 two different variants of shar archives.
98 Pax interchange format is an extension of the tar archive format that
99 eliminates essentially all of the limitations of historic tar formats
100 in a standard fashion that is supported
103 implementations on many systems as well as several newer implementations of
105 Note that the default write format will suppress the pax extended
106 attributes for most entries; explicitly requesting pax format will
107 enable those attributes for all entries.
109 The read and write APIs are accessed through the
112 .Fn archive_write_XXX
113 functions, respectively, and either can be used independently
116 The rest of this manual page provides an overview of the library
118 More detailed information can be found in the individual manual
119 pages for each API or utility function.
121 .Sh READING AN ARCHIVE
123 .Xr libarchive_read 3 .
125 .Sh WRITING AN ARCHIVE
127 .Xr libarchive_write 3 .
129 .Sh WRITING ENTRIES TO DISK
131 .Xr archive_write_disk 3
132 API allows you to write
134 objects to disk using the same API used by
135 .Xr archive_write 3 .
137 .Xr archive_write_disk 3
138 API is used internally by
139 .Fn archive_read_extract ;
140 using it directly can provide greater control over how entries
142 This API also makes it possible to share code between
143 archive-to-archive copy and archive-to-disk extraction
145 .Sh READING ENTRIES FROM DISK
147 .Xr archive_read_disk 3
148 provides some support for populating
150 objects from information in the filesystem.
152 Detailed descriptions of each function are provided by the
153 corresponding manual pages.
155 All of the functions utilize an opaque
157 datatype that provides access to the archive contents.
160 .Tn struct archive_entry
161 structure contains a complete description of a single archive
163 It uses an opaque interface that is fully documented in
164 .Xr archive_entry 3 .
166 Users familiar with historic formats should be aware that the newer
167 variants have eliminated most restrictions on the length of textual fields.
168 Clients should not assume that filenames, link names, user names, or
169 group names are limited in length.
170 In particular, pax interchange format can easily accommodate pathnames
171 in arbitrary character sets that exceed
174 Most functions return
176 (zero) on success, non-zero on error.
177 The return value indicates the general severity of the error, ranging
180 which indicates a minor problem that should probably be reported
183 which indicates a serious problem that will prevent any further
184 operations on this archive.
187 function can be used to retrieve a numeric error code (see
190 .Fn archive_error_string
191 returns a textual error message suitable for display.
195 .Fn archive_write_new
196 return pointers to an allocated and initialized
200 .Fn archive_read_data
202 .Fn archive_write_data
203 return a count of the number of bytes actually read or written.
204 A value of zero indicates the end of the data for this entry.
205 A negative value indicates an error, in which case the
208 .Fn archive_error_string
209 functions can be used to obtain more information.
211 There are character set conversions within the
213 functions that are impacted by the currently-selected locale.
216 .Xr archive_entry 3 ,
219 .Xr archive_write 3 ,
224 library first appeared in
230 library was written by
231 .An Tim Kientzle Aq kientzle@acm.org .
233 Some archive formats support information that is not supported by
234 .Tn struct archive_entry .
235 Such information cannot be fully archived or restored using this library.
236 This includes, for example, comments, character sets,
237 or the arbitrary key/value pairs that can appear in
238 pax interchange format archives.
240 Conversely, of course, not all of the information that can be
242 .Tn struct archive_entry
243 is supported by all formats.
244 For example, cpio formats do not support nanosecond timestamps;
245 old tar formats do not support large device numbers.
248 .Xr archive_read_disk 3
249 API should support iterating over filesystems;
250 that would make it possible to share code among
251 disk-to-archive, archive-to-archive, archive-to-disk,
252 and disk-to-disk operations.
253 Currently, it only supports reading the
254 information for a single file.
255 (Which is still quite useful, as it hides a lot
256 of system-specific details.)