README
1README for libarchive bundle.
2
3Questions? Issues?
4 * http://www.libarchive.org is the home for ongoing
5 libarchive development, including documentation, and
6 links to the libarchive mailing lists.
7 * To report an issue, use the issue tracker at
8 http://code.google.com/p/libarchive/issues/list
9 * To submit an enhancement to libarchive, please submit
10 a pull request via GitHub.
11 https://github.com/libarchive/libarchive/pulls
12
13This distribution bundle includes the following components:
14 * libarchive: a library for reading and writing streaming archives
15 * tar: the 'bsdtar' program is a full-featured 'tar'
16 replacement built on libarchive
17 * cpio: the 'bsdcpio' program is a different interface to
18 essentially the same functionality
19 * examples: Some small example programs that you may find useful.
20 * examples/minitar: a compact sample demonstrating use of libarchive.
21 * contrib: Various items sent to me by third parties;
22 please contact the authors with any questions.
23
24The top-level directory contains the following information files:
25 * NEWS - highlights of recent changes
26 * COPYING - what you can do with this
27 * INSTALL - installation instructions
28 * README - this file
29 * configure - configuration script, see INSTALL for details.
30 * CMakeLists.txt - input for "cmake" build tool, see INSTALL
31
32The following files in the top-level directory are used by the
33'configure' script:
34 * Makefile.am, aclocal.m4, configure.ac
35 - used to build this distribution, only needed by maintainers
36 * Makefile.in, config.h.in
37 - templates used by configure script
38
39Guide to Documentation installed by this system:
40 * bsdtar.1 explains the use of the bsdtar program
41 * bsdcpio.1 explains the use of the bsdcpio program
42 * libarchive.3 gives an overview of the library as a whole
43 * archive_read.3, archive_write.3, archive_write_disk.3, and
44 archive_read_disk.3 provide detailed calling sequences for the read
45 and write APIs
46 * archive_entry.3 details the "struct archive_entry" utility class
47 * archive_internals.3 provides some insight into libarchive's
48 internal structure and operation.
49 * libarchive-formats.5 documents the file formats supported by the library
50 * cpio.5, mtree.5, and tar.5 provide detailed information about these
51 popular archive formats, including hard-to-find details about
52 modern cpio and tar variants.
53The manual pages above are provided in the 'doc' directory in
54a number of different formats.
55
56You should also read the copious comments in "archive.h" and the
57source code for the sample programs for more details. Please let us
58know about any errors or omissions you find.
59
60Currently, the library automatically detects and reads the following fomats:
61 * GNU tar format (including GNU long filenames, long link names, and sparse files)
62 * Solaris 9 extended tar format (including ACLs)
63 * Old V7 tar archives
64 * POSIX ustar
65 * POSIX pax interchange format
66 * POSIX octet-oriented cpio
67 * SVR4 ASCII cpio
68 * POSIX octet-oriented cpio
69 * Binary cpio (big-endian or little-endian)
70 * ISO9660 CD-ROM images (with optional Rockridge or Joliet extensions)
71 * ZIP archives (with uncompressed or "deflate" compressed entries)
72 * GNU and BSD 'ar' archives
73 * 'mtree' format
74 * 7-Zip archives
75 * Microsoft CAB format
76 * LHA and LZH archives
77 * RAR archives
78 * XAR archives
79
80The library also detects and handles any of the following before evaluating the archive:
81 * uuencoded files
82 * files with RPM wrapper
83 * gzip compression
84 * bzip2 compression
85 * compress/LZW compression
86 * lzma, lzip, and xz compression
87
88The library can create archives in any of the following formats:
89 * POSIX ustar
90 * POSIX pax interchange format
91 * "restricted" pax format, which will create ustar archives except for
92 entries that require pax extensions (for long filenames, ACLs, etc).
93 * Old GNU tar format
94 * POSIX octet-oriented cpio
95 * SVR4 "newc" cpio
96 * shar archives
97 * ZIP archives (with uncompressed or "deflate" compressed entries)
98 * GNU and BSD 'ar' archives
99 * 'mtree' format
100 * ISO9660 format
101 * 7-Zip archives
102 * XAR archives
103
104When creating archives, the result can be filtered with any of the following:
105 * uuencode
106 * gzip compression
107 * bzip2 compression
108 * compress/LZW compression
109 * lzma, lzip, and xz compression
110
111Notes about the library architecture:
112
113 * This is a heavily stream-oriented system. There is no direct
114 support for in-place modification or random access.
115
116 * The library is designed to be extended with new compression and
117 archive formats. The only requirement is that the format be
118 readable or writable as a stream and that each archive entry be
119 independent. There are articles on the libarchive Wiki explaining
120 how to extend libarchive.
121
122 * On read, compression and format are always detected automatically.
123
124 * I've attempted to minimize static link pollution. If you don't
125 explicitly invoke a particular feature (such as support for a
126 particular compression or format), it won't get pulled in.
127 In particular, if you don't explicitly enable a particular
128 compression or decompression support, you won't need to link
129 against the corresponding compression or decompression libraries.
130 This also reduces the size of statically-linked binaries in
131 environments where that matters.
132
133 * On read, the library accepts whatever blocks you hand it.
134 Your read callback is free to pass the library a byte at a time
135 or mmap the entire archive and give it to the library at once.
136 On write, the library always produces correctly-blocked output.
137
138 * The object-style approach allows you to have multiple archive streams
139 open at once. bsdtar uses this in its "@archive" extension.
140
141 * The archive itself is read/written using callback functions.
142 You can read an archive directly from an in-memory buffer or
143 write it to a socket, if you wish. There are some utility
144 functions to provide easy-to-use "open file," etc, capabilities.
145
146 * The read/write APIs are designed to allow individual entries
147 to be read or written to any data source: You can create
148 a block of data in memory and add it to a tar archive without
149 first writing a temporary file. You can also read an entry from
150 an archive and write the data directly to a socket. If you want
151 to read/write entries to disk, there are convenience functions to
152 make this especially easy.
153
154 * Note: "pax interchange format" is really an extended tar format,
155 despite what the name says.
156