|Start extended attribute support on the file system named using path. The file system must be an UFS1 file system, and the UFS_EXTATTR kernel option must have been enabled.|
|Stop extended attribute support on the file system named using path. Extended attribute support must previously have been started.|
|initattr [-f] [-p path] attrsize attrfile|
Create and initialize a file to use as an attribute backing file.
You must specify a maximum per-inode size for the attribute in bytes in
as well as the file where the attribute will be stored, using
The -f argument may be used to indicate that it is alright to overwrite an existing attribute backing file; otherwise, if the target file exists, an error will be returned.
The -p path argument may be used to preallocate space for all attributes rather than relying on sparse files to conserve space. This has the advantage of guaranteeing that space will be available for attributes when they are written, preventing low disk space conditions from denying attribute service.
This file should not exist before running initattr.
|Show the attribute header values in the attribute file named by attrfile.|
|enable path attrnamespace attrname attrfile|
|Enable an attribute named attrname in the namespace attrnamespace on the file system identified using path, and backed by initialized attribute file attrfile. Available namespaces are "user" and "system". The backing file must have been initialized using initattr before its first use. Attributes must have been started on the file system prior to the enabling of any attributes.|
|disable path attrnamespace attrname|
|Disable the attributed named attrname in namespace attrnamespace on the file system identified by path. Available namespaces are "user" and "system". The file system must have attributes started on it, and the attribute most have been enabled using enable.|
extattrctl start /
Start extended attributes on the root file system.
extattrctl initattr 17 /.attribute/system/md5
Create an attribute backing file in /.attribute/system/md5, and set the maximum size of each attribute to 17 bytes, with a sparse file used for storing the attributes.
extattrctl enable / system md5 /.attribute/system/md5
Enable an attribute named md5 on the root file system, backed from the file /.attribute/system/md5.
extattrctl disable / md5
Disable the attribute named md5 on the root file system.
extattrctl stop /
Stop extended attributes on the root file system.
ffs(7), getextattr(8), setextattr(8), extattr(9)
Extended attribute support was developed as part of the TrustedBSD Project, and introduced in
.Fx 5.0 . It was developed to support security extensions requiring additional labels to be associated with each file or directory.
Robert N M Watson