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NetBSD 6.1.5 - man page for extattrctl (netbsd section 8)

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EXTATTRCTL(8)			   BSD System Manager's Manual			    EXTATTRCTL(8)

NAME
     extattrctl -- manage UFS1 extended attributes

SYNOPSIS
     extattrctl start path
     extattrctl stop path
     extattrctl initattr [-f] [-p path] attrsize attrfile
     extattrctl showattr attrfile
     extattrctl enable path attrnamespace attrname attrfile
     extattrctl disable path attrnamespace attrname

DESCRIPTION
     The extattrctl utility is the management utility for extended attributes over the UFS1 file
     system.  It allows the starting and stopping of extended attributes on a file system, as
     well as initialization of attribute backing files, and enabling and disabling of specific
     extended attributes on a file system.

     The first argument on the command line indicates the operation to be performed.  Operation
     must be one of the following:

     start path
	     Start extended attribute support on the file system named using path.  The file sys-
	     tem must be a UFS1 file system, and the UFS_EXTATTR kernel option must have been
	     enabled.  If .attribute/user and .attribute/system exist at the filesystem root,
	     extended attributes backed by files in these directories will be automatically
	     enabled.  Note that extended attributes can be automatically started at mount time
	     by using the -o extattr option to mount(8).

     stop path
	     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 attrsize, as well as the file
	     where the attribute will be stored, using attrfile.

	     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.

	     When a user attempts to set a ``user'' or ``system'' extended attribute that lacks a
	     backing file, the kernel will attempt to automatically create it, provided
	     .attribute/user or .attribute/system exist and are writable by the requesting user.

     showattr attrfile
	     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.

EXAMPLES
	   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.

SEE ALSO
     getextattr(1), extattr_get_file(2), extattr(9)

HISTORY
     Extended attribute support was developed as part of the TrustedBSD Project, and introduced
     in FreeBSD 5.0 and NetBSD 4.0.  It was developed to support security extensions requiring
     additional labels to be associated with each file or directory.  Backing file autocreation
     was added in NetBSD 6.0.

AUTHORS
     Robert N M Watson

BUGS
     extattrctl works only on UFS1 file systems.  The kernel support for extended attribute back-
     ing files and this control program should be generalized for any file system that lacks
     native extended attribute support.

BSD					  June 17, 2011 				      BSD
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