ARCHIVE_WRITE_OPTIONS(3) Introduction to Library Functions

NAME

archive_write_set_filter_option, archive_write_set_format_option,
archive_write_set_option, archive_write_set_options - functions
controlling options for writing archives

LIBRARY

Streaming Archive Library (libarchive, -larchive)

SYNOPSIS

int
archive_write_set_filter_option(struct archive *, const char *module,
const char *option, const char *value);

int
archive_write_set_format_option(struct archive *, const char *module,
const char *option, const char *value);

int
archive_write_set_option(struct archive *, const char *module,
const char *option, const char *value);

int
archive_write_set_options(struct archive *, const char *options);

DESCRIPTION

These functions provide a way for libarchive clients to configure
specific write modules.

archive_write_set_filter_option(), archive_write_set_format_option()
Specifies an option that will be passed to the currently-
registered filters (including decompression filters) or format
readers.

If option and value are both NULL, these functions will do
nothing and ARCHIVE_OK will be returned. If option is NULL but
value is not, these functions will do nothing and
ARCHIVE_FAILED will be returned.

If module is not NULL, option and value will be provided to the
filter or reader named module. The return value will be either
ARCHIVE_OK if the option was successfully handled or
ARCHIVE_WARN if the option was unrecognized by the module or
could otherwise not be handled. If there is no such module,
ARCHIVE_FAILED will be returned.

If module is NULL, option and value will be provided to every
registered module. If any module returns ARCHIVE_FATAL, this
value will be returned immediately. Otherwise, ARCHIVE_OK will
be returned if any module accepts the option, and
ARCHIVE_FAILED in all other cases.

archive_write_set_option()
Calls archive_write_set_format_option(), then
archive_write_set_filter_option(). If either function returns
ARCHIVE_FATAL, ARCHIVE_FATAL will be returned immediately.
Otherwise, the greater of the two values will be returned.

archive_write_set_options()
options is a comma-separated list of options. If options is
NULL or empty, ARCHIVE_OK will be returned immediately.

Individual options have one of the following forms:
option=value
The option/value pair will be provided to every module.
Modules that do not accept an option with this name
will ignore it.
option The option will be provided to every module with a
value of "1".
!option
The option will be provided to every module with a NULL
value.
module:option=value, module:option, module:!option
As above, but the corresponding option and value will
be provided only to modules whose name matches module.

OPTIONS

Filter b64encode
mode The value is interpreted as octal digits specifying the
file mode.
name The value specifies the file name.
Filter bzip2
compression-level
The value is interpreted as a decimal integer
specifying the bzip2 compression level. Supported
values are from 1 to 9.
Filter gzip
compression-level
The value is interpreted as a decimal integer
specifying the gzip compression level. Supported values
are from 0 to 9.
timestamp
Store timestamp. This is enabled by default.
Filter lrzip
compression=type
Use type as compression method. Supported values are
"bzip2", "gzipi", "lzo" (ultra fast), and "zpaq" (best,
extremely slow).
compression-level
The value is interpreted as a decimal integer
specifying the lrzip compression level. Supported
values are from 1 to 9.
Filter lz4
compression-level
The value is interpreted as a decimal integer
specifying the lz4 compression level. Supported values
are from 0 to 9.
stream-checksum
Enable stream checksum. This is enabled by default.
block-checksum
Enable block checksum. This is disabled by default.
block-size
The value is interpreted as a decimal integer
specifying the lz4 compression block size. Supported
values are from 4 to 7 (default).
block-dependence
Use the previous block of the block being compressed
for a compression dictionary to improve compression
ratio. This is disabled by default.
Filter lzop
compression-level
The value is interpreted as a decimal integer
specifying the lzop compression level. Supported values
are from 1 to 9.
Filter uuencode
mode The value is interpreted as octal digits specifying the
file mode.
name The value specifies the file name.
Filter xz
compression-level
The value is interpreted as a decimal integer
specifying the compression level. Supported values are
from 0 to 9.
threads
The value is interpreted as a decimal integer
specifying the number of threads for multi-threaded
lzma compression. If supported, the default value is
read from lzma_cputhreads().
Filter zstd
compression-level
The value is interpreted as a decimal integer
specifying the compression level. Supported values
depend on the library version, common values are from 1
to 22.
long Enables long distance matching. The value is
interpreted as a decimal integer specifying log2 window
size in bytes. Values from 10 to 30 for 32 bit, or 31
for 64 bit, are supported.
threads
The value is interpreted as a decimal integer
specifying the number of threads for multi-threaded
zstd compression. If set to 0, zstd will attempt to
detect and use the number of physical CPU cores.
Format 7zip
compression
The value is one of "store", "copy", "deflate",
"bzip2", "lzma1", "lzma2" or "ppmd" to indicate how the
following entries should be compressed. The values
"store" and "copy" are synonyms. Note that this
setting is ignored for directories, symbolic links, and
other special entries.
compression-level
The value is interpreted as a decimal integer
specifying the compression level. Values between 0 and
9 are supported, with the exception of bzip2 which only
supports values between 1 and 9. The interpretation of
the compression level depends on the chosen compression
method.
Format bin
hdrcharset
The value is used as a character set name that will be
used when translating file names.
Format gnutar
hdrcharset
The value is used as a character set name that will be
used when translating file, group and user names.
Format iso9660 - volume metadata
These options are used to set standard ISO9660 metadata.
abstract-file=filename
The file with the specified name will be identified in
the ISO9660 metadata as holding the abstract for this
volume. Default: none.
application-id=filename
The file with the specified name will be identified in
the ISO9660 metadata as holding the application
identifier for this volume. Default: none.
biblio-file=filename
The file with the specified name will be identified in
the ISO9660 metadata as holding the bibliography for
this volume. Default: none.
copyright-file=filename
The file with the specified name will be identified in
the ISO9660 metadata as holding the copyright for this
volume. Default: none.
publisher=filename
The file with the specified name will be identified in
the ISO9660 metadata as holding the publisher
information for this volume. Default: none.
volume-id=string
The specified string will be used as the Volume
Identifier in the ISO9660 metadata. It is limited to
32 bytes. Default: none.
Format iso9660 - boot support
These options are used to make an ISO9660 image that can be
directly booted on various systems.
boot=filename
The file matching this name will be used as the El
Torito boot image file.
boot-catalog=name
The name that will be used for the El Torito boot
catalog. Default: boot.catalog
boot-info-table
The boot image file provided by the boot=filename
option will be edited with appropriate boot information
in bytes 8 through 64. Default: disabled
boot-load-seg=hexadecimal-number
The load segment for a no-emulation boot image.
boot-load-size=decimal-number
The number of "virtual" 512-byte sectors to be loaded
from a no-emulation boot image. Some very old BIOSes
can only load very small images, setting this value to
4 will often allow such BIOSes to load the first part
of the boot image (which will then need to be
intelligent enough to load the rest of itself). This
should not be needed unless you are trying to support
systems with very old BIOSes. This defaults to the
full size of the image.
boot-type=value
Specifies the boot semantics used by the El Torito boot
image: If the value is fd, then the boot image is
assumed to be a bootable floppy image. If the value is
hd, then the boot image is assumed to be a bootable
hard disk image. If the value is no-emulation, the
boot image is used without floppy or hard disk
emulation. If the boot image is exactly 1.2MB, 1.44MB,
or 2.88MB, then the default is fd, otherwise the
default is no-emulation.
Format iso9660 - filename and size extensions
Various extensions to the base ISO9660 format.
allow-ldots
If enabled, allows filenames to begin with a leading
period. If disabled, filenames that begin with a
leading period will have that period replaced by an
underscore character in the standard ISO9660 namespace.
This does not impact names stored in the Rockridge or
Joliet extension area. Default: disabled.
allow-lowercase
If enabled, allows filenames to contain lowercase
characters. If disabled, filenames will be forced to
uppercase. This does not impact names stored in the
Rockridge or Joliet extension area. Default: disabled.
allow-multidot
If enabled, allows filenames to contain multiple period
characters, in violation of the ISO9660 specification.
If disabled, additional periods will be converted to
underscore characters. This does not impact names
stored in the Rockridge or Joliet extension area.
Default: disabled.
allow-period
If enabled, allows filenames to contain trailing period
characters, in violation of the ISO9660 specification.
If disabled, trailing periods will be converted to
underscore characters. This does not impact names
stored in the Rockridge or Joliet extension area.
Default: disabled.
allow-pvd-lowercase
If enabled, the Primary Volume Descriptor may contain
lowercase ASCII characters, in violation of the ISO9660
specification. If disabled, characters will be
converted to uppercase ASCII. Default: disabled.
allow-sharp-tilde
If enabled, sharp and tilde characters will be
permitted in filenames, in violation if the ISO9660
specification. If disabled, such characters will be
converted to underscore characters. Default: disabled.
allow-vernum
If enabled, version numbers will be included with
files. If disabled, version numbers will be
suppressed, in violation of the ISO9660 standard. This
does not impact names stored in the Rockridge or Joliet
extension area. Default: enabled.
iso-level
This enables support for file size and file name
extensions in the core ISO9660 area. The name
extensions specified here do not affect the names
stored in the Rockridge or Joliet extension areas.
iso-level=1
The most compliant form of ISO9660 image.
Filenames are limited to 8.3 uppercase format,
directory names are limited to 8 uppercase
characters, files are limited to 4 GiB, the
complete ISO9660 image cannot exceed 4 GiB.
iso-level=2
Filenames are limited to 30 uppercase
characters with a 30-character extension,
directory names are limited to 30 characters,
files are limited to 4 GiB.
iso-level=3
As with iso-level=2, except that files may
exceed 4 GiB.
iso-level=4
As with iso-level=3, except that filenames may
be up to 193 characters and may include
arbitrary 8-bit characters.
joliet Microsoft's Joliet extensions store a completely
separate set of directory information about each file.
In particular, this information includes Unicode
filenames of up to 255 characters. Default: enabled.
limit-depth
If enabled, libarchive will use directory relocation
records to ensure that no pathname exceeds the ISO9660
limit of 8 directory levels. If disabled, no
relocation will occur. Default: enabled.
limit-dirs
If enabled, libarchive will cause an error if there are
more than 65536 directories. If disabled, there is no
limit on the number of directories. Default: enabled
pad If enabled, 300 kiB of zero bytes will be appended to
the end of the archive. Default: enabled
relaxed-filenames
If enabled, all 7-bit ASCII characters are permitted in
filenames (except lowercase characters unless
allow-lowercase is also specified). This violates
ISO9660 standards. This does not impact names stored
in the Rockridge or Joliet extension area. Default:
disabled.
rockridge
The Rockridge extensions store an additional set of
POSIX-style file information with each file, including
mtime, atime, ctime, permissions, and long filenames
with arbitrary 8-bit characters. These extensions also
support symbolic links and other POSIX file types.
Default: enabled.
Format iso9660 - zisofs support
The zisofs extensions permit each file to be independently
compressed using a gzip-compatible compression. This can
provide significant size savings, but requires the reading
system to have support for these extensions. These extensions
are disabled by default.
compression-level=number
The compression level used by the deflate compressor.
Ranges from 0 (least effort) to 9 (most effort).
Default: 6
zisofs Synonym for zisofs=direct.
zisofs=direct
Compress each file in the archive. Unlike
zisofs=indirect, this is handled entirely within
libarchive and does not require a separate utility.
For best results, libarchive tests each file and will
store the file uncompressed if the compression does not
actually save any space. In particular, files under 2k
will never be compressed. Note that boot image files
are never compressed.
zisofs=indirect
Recognizes files that have already been compressed with
the mkzftree utility and sets up the necessary file
metadata so that readers will correctly identify these
as zisofs-compressed files.
zisofs-exclude=filename
Specifies a filename that should not be compressed when
using zisofs=direct. This option can be provided
multiple times to suppress compression on many files.
Format mtree
cksum, device, flags, gid, gname, indent, link, md5, mode,
nlink, rmd160, sha1, sha256, sha384, sha512, size,
time, uid, uname
Enable a particular keyword in the mtree output.
Prefix with an exclamation mark to disable the
corresponding keyword. The default is equivalent to
"device, flags, gid, gname, link, mode, nlink, size,
time, type, uid, uname".
all Enables all of the above keywords.
use-set
Enables generation of /set lines that specify default
values for the following files and/or directories.
indent XXX needs explanation XXX
Format newc
hdrcharset
The value is used as a character set name that will be
used when translating file names.
Format odc
hdrcharset
The value is used as a character set name that will be
used when translating file names.
Format pwb
hdrcharset
The value is used as a character set name that will be
used when translating file names.
Format pax
hdrcharset
The value is used as a character set name that will be
used when translating file, group and user names. The
value is one of "BINARY" or "UTF-8". With "BINARY"
there is no character conversion, with "UTF-8" names
are converted to UTF-8.
xattrheader
When storing extended attributes, this option
configures which headers should be written. The value
is one of "all", "LIBARCHIVE", or "SCHILY". By
default, both "LIBARCHIVE.xattr" and "SCHILY.xattr"
headers are written.
Format ustar
hdrcharset
The value is used as a character set name that will be
used when translating file, group and user names.
Format v7tar
hdrcharset
The value is used as a character set name that will be
used when translating file, group and user names.
Format warc
omit-warcinfo
Set to "true" to disable output of the warcinfo record.
Format xar
checksum=type
Use type as file checksum method. Supported values are
"none", "md5", and "sha1" (default).
compression=type
Use type as compression method. Supported values are
"none", "bzip2", "gzip" (default), "lzma" and "xz".
compression_level
The value is a decimal integer from 1 to 9 specifying
the compression level.
toc-checksum=type
Use type as table of contents checksum method.
Supported values are "none", "md5" and "sha1"
(default).
Format zip
compression
The value is either "store" or "deflate" to indicate
how the following entries should be compressed. Note
that this setting is ignored for directories, symbolic
links, and other special entries.
compression-level
The value is interpreted as a decimal integer
specifying the compression level. Values between 0 and
9 are supported. A compression level of 0 switches the
compression method to "store", other values will enable
"deflate" compression with the given level.
encryption
Enable encryption using traditional zip encryption.
encryption=type
Use type as encryption type. Supported values are
"zipcrypt" (traditional zip encryption), "aes128"
(WinZip AES-128 encryption) and "aes256" (WinZip
AES-256 encryption).
experimental
This boolean option enables or disables experimental
Zip features that may not be compatible with other Zip
implementations.
fakecrc32
This boolean option disables CRC calculations. All CRC
fields are set to zero. It should not be used except
for testing purposes.
hdrcharset
The value is used as a character set name that will be
used when translating file names.
zip64 Zip64 extensions provide additional file size
information for entries larger than 4 GiB. They also
provide extended file offset and archive size
information when archives exceed 4 GiB. By default,
the Zip writer selectively enables these extensions
only as needed. In particular, if the file size is
unknown, the Zip writer will include Zip64 extensions
to guard against the possibility that the file might be
larger than 4 GiB.

Setting this boolean option will force the writer to
use Zip64 extensions even for small files that would
not otherwise require them. This is primarily useful
for testing.

Disabling this option with !zip64 will force the Zip
writer to avoid Zip64 extensions: It will reject files
with size greater than 4 GiB, it will reject any new
entries once the total archive size reaches 4 GiB, and
it will not use Zip64 extensions for files with unknown
size. In particular, this can improve compatibility
when generating archives where the entry sizes are not
known in advance.

EXAMPLES

The following example creates an archive write handle to create a gzip-
compressed ISO9660 format image. The two options here specify that the
ISO9660 archive will use kernel.img as the boot image for El Torito
booting, and that the gzip compressor should use the maximum
compression level.

a = archive_write_new();
archive_write_add_filter_gzip(a);
archive_write_set_format_iso9660(a);
archive_write_set_options(a, "boot=kernel.img,compression=9");
archive_write_open_filename(a, filename, blocksize);

ERRORS

More detailed error codes and textual descriptions are available from
the archive_errno() and archive_error_string() functions.

SEE ALSO

tar(1), archive_read_set_options(3), archive_write(3), libarchive(3)

HISTORY

The libarchive library first appeared in FreeBSD 5.3.

AUTHORS

The options support for libarchive was originally implemented by
Michihiro NAKAJIMA.

BUGS

illumos January 31, 2020 illumos