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diff --git a/libarchive/libarchive-2.4.17/doc/text/libarchive-formats.5 b/libarchive/libarchive-2.4.17/doc/text/libarchive-formats.5 deleted file mode 100644 index 35eb278..0000000 --- a/libarchive/libarchive-2.4.17/doc/text/libarchive-formats.5 +++ /dev/null @@ -1,180 +0,0 @@ -libarchive-formats(3) FreeBSD Library Functions Manual libarchive-formats(3) - -NAME - libarchive-formats -- archive formats supported by the libarchive library - -DESCRIPTION - The libarchive(3) library reads and writes a variety of streaming archive - formats. Generally speaking, all of these archive formats consist of a - series of ``entries''. Each entry stores a single file system object, - such as a file, directory, or symbolic link. - - The following provides a brief description of each format supported by - libarchive, with some information about recognized extensions or limita- - tions of the current library support. Note that just because a format is - supported by libarchive does not imply that a program that uses - libarchive will support that format. Applications that use libarchive - specify which formats they wish to support. - - Tar Formats - The libarchive(3) library can read most tar archives. However, it only - writes POSIX-standard ``ustar'' and ``pax interchange'' formats. - - All tar formats store each entry in one or more 512-byte records. The - first record is used for file metadata, including filename, timestamp, - and mode information, and the file data is stored in subsequent records. - Later variants have extended this by either appropriating undefined areas - of the header record, extending the header to multiple records, or by - storing special entries that modify the interpretation of subsequent - entries. - - gnutar The libarchive(3) library can read GNU-format tar archives. It - currently supports the most popular GNU extensions, including - modern long filename and linkname support, as well as atime and - ctime data. The libarchive library does not support multi-volume - archives, nor the old GNU long filename format. It can read GNU - sparse file entries, including the new POSIX-based formats, but - cannot write GNU sparse file entries. - - pax The libarchive(3) library can read and write POSIX-compliant pax - interchange format archives. Pax interchange format archives are - an extension of the older ustar format that adds a separate entry - with additional attributes stored as key/value pairs. The pres- - ence of this additional entry is the only difference between pax - interchange format and the older ustar format. The extended - attributes are of unlimited length and are stored as UTF-8 Uni- - code strings. Keywords defined in the standard are in all lower- - case; vendors are allowed to define custom keys by preceding them - with the vendor name in all uppercase. When writing pax ar- - chives, libarchive uses many of the SCHILY keys defined by Joerg - Schilling's ``star'' archiver. The libarchive library can read - most of the SCHILY keys. It silently ignores any keywords that - it does not understand. - - restricted pax - The libarchive library can also write pax archives in which it - attempts to suppress the extended attributes entry whenever pos- - sible. The result will be identical to a ustar archive unless - the extended attributes entry is required to store a long file - name, long linkname, extended ACL, file flags, or if any of the - standard ustar data (user name, group name, UID, GID, etc) cannot - be fully represented in the ustar header. In all cases, the - result can be dearchived by any program that can read POSIX-com- - pliant pax interchange format archives. Programs that correctly - read ustar format (see below) will also be able to read this for- - mat; any extended attributes will be extracted as separate files - stored in PaxHeader directories. - - ustar The libarchive library can both read and write this format. This - format has the following limitations: - o Device major and minor numbers are limited to 21 bits. Nodes - with larger numbers will not be added to the archive. - o Path names in the archive are limited to 255 bytes. (Shorter - if there is no / character in exactly the right place.) - o Symbolic links and hard links are stored in the archive with - the name of the referenced file. This name is limited to 100 - bytes. - o Extended attributes, file flags, and other extended security - information cannot be stored. - o Archive entries are limited to 2 gigabytes in size. - Note that the pax interchange format has none of these restric- - tions. - - The libarchive library can also read a variety of commonly-used exten- - sions to the basic tar format. In particular, it supports base-256 val- - ues in certain numeric fields. This essentially removes the limitations - on file size, modification time, and device numbers. - - The first tar program appeared in Seventh Edition Unix in 1979. The - first official standard for the tar file format was the ``ustar'' (Unix - Standard Tar) format defined by POSIX in 1988. POSIX.1-2001 extended the - ustar format to create the ``pax interchange'' format. - - Cpio Formats - The libarchive library can read a number of common cpio variants and can - write ``odc'' and ``newc'' format archives. A cpio archive stores each - entry as a fixed-size header followed by a variable-length filename and - variable-length data. Unlike tar, cpio does only minimal padding of the - header or file data. There are a variety of cpio formats, which differ - primarily in how they store the initial header: some store the values as - octal or hexadecimal numbers in ASCII, others as binary values of varying - byte order and length. - - binary The libarchive library can read both big-endian and little-endian - variants of the original binary cpio format. This format used - 32-bit binary values for file size and mtime, and 16-bit binary - values for the other fields. - - odc The libarchive library can both read and write this POSIX-stan- - dard format. This format stores the header contents as octal - values in ASCII. It is standard, portable, and immune from byte- - order confusion. File sizes and mtime are limited to 33 bits - (8GB file size), other fields are limited to 18 bits. - - SVR4 The libarchive library can read both CRC and non-CRC variants of - this format. The SVR4 format uses eight-digit hexadecimal values - for all header fields. This limits file size to 4GB, and also - limits the mtime and other fields to 32 bits. The SVR4 format - can optionally include a CRC of the file contents, although - libarchive does not currently verify this CRC. - - Cpio first appeared in PWB/UNIX 1.0, which was released within AT&T in - 1977. PWB/UNIX 1.0 formed the basis of System III Unix, released outside - of AT&T in 1981. This makes cpio older than tar, although cpio was not - included in Version 7 AT&T Unix. As a result, the tar command became - much better known in universities and research groups that used Version - 7. The combination of the find and cpio utilities provided very precise - control over file selection. Unfortunately, the format has many limita- - tions that make it unsuitable for widespread use. Only the POSIX format - permits files over 4GB, and its 18-bit limit for most other fields makes - it unsuitable for modern systems. In addition, cpio formats only store - numeric UID/GID values (not usernames and group names), which can make it - very difficult to correctly transfer archives across systems with dissim- - ilar user numbering. - - Shar Formats - A ``shell archive'' is a shell script that, when executed on a POSIX-com- - pliant system, will recreate a collection of file system objects. The - libarchive library can write two different kinds of shar archives: - - shar The traditional shar format uses a limited set of POSIX commands, - including echo(1), mkdir(1), and sed(1). It is suitable for - portably archiving small collections of plain text files. How- - ever, it is not generally well-suited for large archives (many - implementations of sh(1) have limits on the size of a script) nor - should it be used with non-text files. - - shardump - This format is similar to shar but encodes files using - uuencode(1) so that the result will be a plain text file regard- - less of the file contents. It also includes additional shell - commands that attempt to reproduce as many file attributes as - possible, including owner, mode, and flags. The additional com- - mands used to restore file attributes make shardump archives less - portable than plain shar archives. - - ISO9660 format - Libarchive can read and extract from files containing ISO9660-compliant - CDROM images. It also has partial support for Rockridge extensions. In - many cases, this can remove the need to burn a physical CDROM. It also - avoids security and complexity issues that come with virtual mounts and - loopback devices. - - Zip format - Libarchive can extract from most zip format archives. It currently only - supports uncompressed entries and entries compressed with the ``deflate'' - algorithm. Older zip compression algorithms are not supported. - - Archive (library) file format - The Unix archive format (commonly created by the ar(1) archiver) is a - general-purpose format which is used almost exclusively for object files - to be read by the link editor ld(1). The ar format has never been stan- - dardised. There are two common variants: the GNU format derived from - SVR4, and the BSD format, which first appeared in 4.4BSD. Libarchive - provides read and write support for both variants. - -SEE ALSO - ar(1), cpio(1), mkisofs(1), shar(1), tar(1), zip(1), zlib(3), cpio(5), - mtree(5), tar(5) - -FreeBSD 6.0 April 27, 2004 FreeBSD 6.0 |