PACKAGE(5) BSD File Formats Manual PACKAGE(5)
package -- format for OpenBSD binary packages
Binary packages for OpenBSD can be created using pkg_create(1) and are
usually manipulated using pkg_add(1), pkg_mklocatedb(1), or pkg_info(1).
The basic underlying format is an archive following the ustar specifica-
tion that can be handled with tar(1) and compressed using gzip(1).
Package names always end in ``.tgz''; the file name itself should conform
Note that the base distribution tarballs of OpenBSD (e.g. baseXX.tgz,
compXX.tgz, ...) are not binary packages fit for pkg_add(1).
All types of archive contents can be present in a package, including
files, directories, hardlinks, symlinks, fifos, block and character
In order to allow just-in-time extraction, packages always begin with a
table of contents, named +CONTENTS. This table of contents can be read
using the API described in OpenBSD::PackingList(3p).
All the remaining information in the archive should be referenced in the
packing-list, including all relevant information: symlinks destinations,
special permissions, and file owners (pkg_create(1) and pkg_add(1)
actually enforce this). See pkg_create(1) for annotation details.
This table of contents is always followed by a few special files, some of
which are optional: the package description (+DESC), a display message
The basic ustar format has some limitations with respect to file names.
Packages now use the "extended record specification" (header type x) for
long links and long file names. Other extended ustar headers are cur-
rently recognized, but not supported.
Starting with OpenBSD 5.5, the compressed archive may be composed of sev-
eral gzip(1) archives concatenated together. gzip(1) doesn't mind, and
tar(1) is happy as long as the uncompressed stream is sane. This allows
for faster signing and better rsync properties.
Starting with OpenBSD 5.6, tarballs are stored "out-of-order": each ar-
chive entry will match an entry in the packing-list (and all file-like
entries will be matched), but the order will be adjusted so that most
recently changed files come first, in order to allow faster updates.
PACKING LIST ANNOTATIONS
User annotations are described in pkg_create(1). The following annota-
tions are automatically inserted during package creation and installa-
List of architectures for which this package is intended. This
corresponds to -A arches of pkg_create(1)
@comment pkgpath=path cdrom=yes/no ftp=yes/no
Historical accident. This specific comment encodes the actual -D
FULLPKGPATH, -D CDROM, and -D FTP arguments to pkg_create(1).
Record a dependency declared using the option -P of
Record a digital signature of the packing-list, corresponding to
pkg_create(1)'s -s option.
Added after a file entry by package to record that the entry is
actually a hard link.
Used internally to record the settings of -L option.
Set the name of the package. This name is potentially different
than the name of the file it came in, and is used when keeping
track of the package for later deinstallation. pkg_create(1)
will derive this field from the package file name.
Some options are automatically inserted by the package tools:
Set by fw_update(1) to trigger firmware-specific han-
dling. In particular, firmwares are hidden from normal
Record that a package has been explicitly installed by
the user, and not as a result of a dependency look-up.
Refer to pkg_add(1)'s -a option for details.
@sha Added after a file entry by pkg_create(1) to record the files's
cryptographic checksum, as a sha256 digest encoded in base64.
Internal annotation necessary to identify packages signed with
signify(1) keys, as those keys don't carry any identity.
@size Added after a file entry by pkg_create(1) to record a file size.
Added after a file entry by pkg_create(1) to record that the
entry is actually a symbolic link.
@url Original location of the package, automatically recorded in
installed packages by pkg_add(1).
Added after a file entry to record the actual file timestamp.
The package tools read and process that annotation correctly.
Starting with OpenBSD 5.7, pkg_create(1) will migrate timestamps
from the tarball meta-info to the packing-list to better create
unchanging archive chunks.
Record a library requirement declared using the option -W of
All information within a package is checksummed, using SHA256 since
OpenBSD 4.4. During creation and installation, meta-information, such as
file owners and permissions, are also checked: any important stuff that
isn't recorded in the packing-list is an error.
Packing-lists can be signed. If a signature is found, then it will be
checked during installation, and failure to verify will prevent the pack-
age from installing correctly. Currently, signify(1) and X.509-style
signatures are supported. X.509 signatures rely on a certificate author-
ity file being present as /etc/ssl/pkgca.pem and all signatures will be
checked against it. Once the packing-list signature is checked, all
individual packing elements will be checksummed, resulting in a
'just-in-time' signature checking.
Fat packages were removed in OpenBSD 5.1, since no practical application
pkg_add(1), pkg_create(1), pkg_info(1), pkg_sign(1), packages(7),
Packages are valid gzip'ed ustar archives that can be extracted using
tar(1). In particular, hardlink names should be valid, and all items
will extract to different names. However, it may be a bit difficult to
make sense of the package contents without peeking at the packing-list.
BSD April 25, 2017 BSD