Provided by: am-utils_6.2+rc20110530-3.2ubuntu1_amd64 bug


       hlfsd - home-link file system daemon


       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 ] ]


       Hlfsd is a daemon which implements a filesystem 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 anywhere.

       Hlfsd operates by mounting itself as an NFS server for the directory containing  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  SIGTERM  sent  to  hlfsd  will  cause it to shutdown.  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


       -a alt_dir
              Alternate directory.  The name of the directory to which the symbolic 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 administrators will
              run a script to resend this "lost mail" to its owner.

       -c cache-interval
              Caching  interval.   Hlfsd  will  cache  the  validity of home directories for this
              interval, in seconds.  Entries which have been  verified  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

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

       -g group
              Set  the  special  group HLFS_GID to group.  Programs such as from or comsat, which
              access the mailboxes of other users) must be setgid 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 contains 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     Print  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  separated  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 discouraged, as it  may  result  in  loss  or  mis-
              delivery  of  mail.   The  option  is  ignored  on  systems  that  can turn off the

       -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
              documented  here.   A  fuller  description  is  available in the program source.  A
              SIGUSR1 sent to hlfsd will cause it to dump its internal password map to  the  file

       -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  otherwise  be
              compliant with Unix System 7 colon-delimited format passwd(4).


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

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

            directory to which home symbolic link returned by hlfsd points if  it  is  unable  to
            verify the that user's home directory is accessible.


       mail(1),  getgrent(3),  getpwent(3),  mnttab(4), passwd(4), mtab(5), amd(8), automount(8),
       cron(8), mount(8), sendmail(8), umount(8).

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

       ``am-utils'' info(1) entry.

       Linux NFS and Automounter Administration by Erez Zadok, ISBN 0-7821-2739-8, (Sybex, 2001).


       Erez Zadok <>, Computer Science Department, Stony Brook University, Stony
       Brook, New York, USA.  and Alexander Dupuy  <>,  System  Management  ARTS,
       White Plains, New York, USA.

       Other authors and contributors to am-utils are listed in the AUTHORS file distributed with

                                        14 September 1993                                HLFSD(8)