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

NAME
     hlfsd -- home-link file system daemon

SYNOPSIS
     hlfsd [-fhnpvC] [-a alt_dir] [-c cache-interval] [-g group]
           [-i reload-interval] [-l logfile] [-o mount-options]
           [-x log-options] [-D debug-options] [-P password-file]
           [linkname [subdir]]

DESCRIPTION
     hlfsd is a daemon which implements a file system containing a symbolic
     link to subdirectory within a user's home directory, depending on the
     user which accessed that link.  It was primarily designed to redirect
     incoming mail to users' home directories, so that it can read from any-
     where.

     hlfsd operates by mounting itself as an NFS server for the directory con-
     taining linkname, which defaults to /hlfs/home.  Lookups within that
     directory are handled by hlfsd, which uses the password map to determine
     how to resolve the lookup.  The directory will be created if it doesn't
     already exist.  The symbolic link will be to the accessing user's home
     directory, with subdir appended to it.  If not specified, subdir defaults
     to .hlfsdir.  This directory will also be created if it does not already
     exist.

     A SIGHUP will flush the internal caches, and reload the password map.  It
     will also close and reopen the log file, to enable the original log file
     to be removed or rotated.  A SIGUSR1 will cause it to dump its internal
     table of user IDs and home directories to the file
     /usr/tmp/hlfsd.dump.XXXXXX.

OPTIONS
     -a alt_dir
             Alternate directory.  The name of the directory to which the sym-
             bolic link returned by hlfsd will point, if it cannot access the
             home directory of the user.  This defaults to /var/hlfs.  This
             directory will be created  if it doesn't exist.  It is expected
             that either users will read these files, or the system adminis-
             trators will run a script to resend this ``lost mail'' to its
             owner.

     -c cache-interval
             Caching interval.  hlfsd will cache the validity of home directo-
             ries for this interval, in seconds.  Entries which have been ver-
             ified within the last cache-interval seconds will not be verified
             again, since the operation could be expensive, and the entries
             are most likely still valid.  After the interval has expired,
             hlfsd will re-verify the validity of the user's home directory,
             and reset the cache time-counter.  The default value for
             cache-interval is 300 seconds (5 minutes).

     -f      Force fast startup.  This option tells hlfsd to skip startup-time
             consistency checks such as existence of mount directory, alter-
             nate spool directory, symlink to be hidden under the mount direc-
             tory, their permissions and validity.

     -g group
             Set the special group HLFS_GID to group.  Programs such as
             comsat, (which access the mailboxes of other users) must be set-
             gid HLFS_GID to work properly.  The default group is ``hlfs''.
             If no group is provided, and there is no group ``hlfs'', this
             feature is disabled.

     -h      Help.  Print a brief help message, and exit.

     -i reload-interval
             Map-reloading interval.  Each reload-interval seconds, hlfsd will
             reload the password map.  hlfsd needs the password map for the
             UIDs and home directory pathnames.  hlfsd schedules a SIGALRM to
             reload the password maps.  A SIGHUP sent to hlfsd will force it
             to reload the maps immediately.   The default value for
             reload-interval is 900 seconds (15 minutes).

     -l logfile
             Specify a log file to which hlfsd will record events.  If logfile
             is the string syslog then the log messages will be sent to the
             system log daemon by syslog(3), using the LOG_DAEMON facility.
             This is also the default.

     -n      No verify.  hlfsd will not verify the validity of the symbolic
             link it will be returning, or that the user's home directory con-
             tains sufficient disk-space for spooling.  This can speed up
             hlfsd at the cost of possibly returning symbolic links to home
             directories which are not currently accessible or are full.  By
             default, hlfsd validates the symbolic-link in the background.
             The -n option overrides the meaning of the -c option, since no
             caching is necessary.

     -o mount-options
             Mount options.  Mount options which hlfsd will use to mount
             itself on top of dirname.  By default, mount-options is set to
             "ro".  If the system supports symbolic-link caching, default
             options are set to "ro,nocache".

     -p      Prints PID.  Outputs the process-id of hlfsd to standard output
             where it can be saved into a file.

     -v      Version.  Displays version information to standard error.

     -x log-options
             Specify run-time logging options.  The options are a comma sepa-
             rated list chosen from: fatal, error, user, warn, info, map,
             stats, all.

     -C      Force hlfsd to run on systems that cannot turn off the NFS
             attribute-cache.  Use of this option on those systems is discour-
             aged, as it may result in loss or mis-delivery of mail.  The
             option is ignored on systems that can turn off the attribute-
             cache.

     -D log-options
             Select from a variety of debugging options.  Prefixing an option
             with the string "no" reverses the effect of that option.  Options
             are cumulative.  The most useful option is all.  Since this
             option is only used for debugging other options are not docu-
             mented here.  A fuller description is available in the program
             source.  A SIGUSR1 sent to hlfsd will cause it to dump its inter-
             nal password map to the file /usr/tmp/hlfsd.dump.XXXXXX.

     -P password-file
             Read the user-name, user-id, and home directory information from
             the file password-file.  Normally, hlfsd will use getpwent(3) to
             read the password database.  This option allows you to override
             the default database, and is useful if you want to map users'
             mail files to a directory other than their home directory.  Only
             the username, uid, and home-directory fields of the file
             password-file are read and checked.  All other fields are
             ignored.  The file password-file must be compliant with UNIX Sys-
             tem 7 colon-delimited format passwd(5).

FILES
     /hlfs
           directory under which hlfsd mounts itself and manages the symbolic
           link home.

     .hlfsdir
           default sub-directory in the user's home directory, to which the
           home symbolic link returned by hlfsd points.

     /var/hlfs
           directory to which home symbolic link returned by hlfsd points if
           it is unable to verify the that user's home directory is accessi-
           ble.

SEE ALSO
     mail(1), getgrent(3), getpwent(3), mtab(5), passwd(5), amd(8), cron(8),
     mount(8), sendmail(8), umount(8)

     "HLFSD: Delivering Email to Your $HOME", Proc. LISA-VII, The 7th Usenix
     System Administration Conference, November 1993.

AUTHORS
     Erez Zadok <ezkATcs.edu>, Department of Computer Science, Colum-
     bia University, New York, USA.

     Alexander Dupuy <dupuyATsmarts.com>, System Management ARTS, White Plains,
     New York, USA.

HISTORY
     The hlfsd utility appeared in FreeBSD 3.0.

BSD                           September 14, 1993                           BSD