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