1HLFSD(8)                    System Manager's Manual                   HLFSD(8)
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NAME

6       hlfsd - home-link file system daemon
7

SYNOPSIS

9       hlfsd  [  -fhnpvC ] [ -a alt_dir ] [ -c cache-interval ] [ -g group ] [
10       -i reload-interval ] [ -l logfile ] [ -o  mount-options  ]  [  -x  log-
11       options ] [ -D debug-options ] [ -P password-file ] [ linkname [ subdir
12       ] ]
13

DESCRIPTION

15       Hlfsd is a daemon which implements a filesystem containing  a  symbolic
16       link  to  subdirectory within a user's home directory, depending on the
17       user which accessed that link.  It was primarily designed  to  redirect
18       incoming mail to users' home directories, so that it can read from any‐
19       where.
20
21       Hlfsd operates by mounting itself as an NFS server  for  the  directory
22       containing linkname, which defaults to /hlfs/home.  Lookups within that
23       directory are handled by hlfsd, which uses the password map  to  deter‐
24       mine  how  to  resolve the lookup.  The directory will be created if it
25       doesn't already exist.  The symbolic link  will  be  to  the  accessing
26       user's  home  directory, with subdir appended to it.  If not specified,
27       subdir defaults to .hlfsdir.  This directory will also be created if it
28       does not already exist.
29
30       A SIGTERM sent to hlfsd will cause it to shutdown.  A SIGHUP will flush
31       the internal caches, and reload the password map.  It will  also  close
32       and  reopen the log file, to enable the original log file to be removed
33       or rotated.  A SIGUSR1 will cause it to dump its internal table of user
34       IDs and home directories to the file /usr/tmp/hlfsd.dump.XXXXXX.
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OPTIONS

37       -a alt_dir
38              Alternate  directory.   The  name  of the directory to which the
39              symbolic link returned by hlfsd will point, if it cannot  access
40              the  home  directory  of  the user.  This defaults to /var/hlfs.
41              This directory will be created  if  it  doesn't  exist.   It  is
42              expected  that either users will read these files, or the system
43              administrators will run a script to resend this "lost  mail"  to
44              its owner.
45
46       -c cache-interval
47              Caching  interval.  Hlfsd will cache the validity of home direc‐
48              tories for this interval, in seconds.  Entries which  have  been
49              verified within the last cache-interval seconds will not be ver‐
50              ified again, since the operation could  be  expensive,  and  the
51              entries  are  most  likely  still valid.  After the interval has
52              expired, hlfsd will re-verify the validity of  the  user's  home
53              directory,  and reset the cache time-counter.  The default value
54              for cache-interval is 300 seconds (5 minutes).
55
56       -f     Force fast startup.  This option tells hlfsd  to  skip  startup-
57              time  consistency  checks  such as existence of mount directory,
58              alternate spool directory, symlink to be hidden under the  mount
59              directory, their permissions and validity.
60
61       -g group
62              Set  the special group HLFS_GID to group.  Programs such as from
63              or comsat, which access the mailboxes of other  users)  must  be
64              setgid  HLFS_GID to work properly.  The default group is "hlfs".
65              If no group is provided, and there is no group "hlfs", this fea‐
66              ture is disabled.
67
68       -h     Help.  Print a brief help message, and exit.
69
70       -i reload-interval
71              Map-reloading  interval.   Each  reload-interval  seconds, hlfsd
72              will reload the password map.  Hlfsd needs the password map  for
73              the  UIDs  and  home  directory  pathnames.   Hlfsd  schedules a
74              SIGALRM to reload the password maps.  A  SIGHUP  sent  to  hlfsd
75              will  force  it  to  reload  the maps immediately.   The default
76              value for reload-interval is 900 seconds (15 minutes.)
77
78       -l logfile
79              Specify a log file to which hlfsd will record events.   If  log‐
80              file  is the string syslog then the log messages will be sent to
81              the system log daemon by syslog(3), using the LOG_DAEMON  facil‐
82              ity.  This is also the default.
83
84       -n     No  verify.   Hlfsd will not verify the validity of the symbolic
85              link it will be returning, or that  the  user's  home  directory
86              contains  sufficient disk-space for spooling.  This can speed up
87              hlfsd at the cost of possibly returning symbolic links  to  home
88              directories  which are not currently accessible or are full.  By
89              default, hlfsd validates the symbolic-link  in  the  background.
90              The  -n  option overrides the meaning of the -c option, since no
91              caching is necessary.
92
93       -o mount-options
94              Mount options.  Mount options which  hlfsd  will  use  to  mount
95              itself  on  top of dirname.  By default, mount-options is set to
96              "ro".  If the system  supports  symbolic-link  caching,  default
97              options are set to "ro,nocache".
98
99       -p     Print  PID.   Outputs the process-id of hlfsd to standard output
100              where it can be saved into a file.
101
102       -v     Version.  Displays version information to standard error.
103
104       -x log-options
105              Specify run-time logging options.  The options are a comma sepa‐
106              rated  list  chosen  from:  fatal, error, user, warn, info, map,
107              stats, all.
108
109       -C     Force hlfsd to run on systems  that  cannot  turn  off  the  NFS
110              attribute-cache.   Use  of  this option on those systems is dis‐
111              couraged, as it may result in loss or mis-delivery of mail.  The
112              option  is  ignored  on systems that can turn off the attribute-
113              cache.
114
115       -D log-options
116              Select from a variety of debugging options.  Prefixing an option
117              with  the string no reverses the effect of that option.  Options
118              are cumulative.  The most useful  option  is  all.   Since  this
119              option  is  only  used for debugging other options are not docu‐
120              mented here.  A fuller description is available in  the  program
121              source.   A  SIGUSR1  sent  to  hlfsd  will cause it to dump its
122              internal password map to the file /usr/tmp/hlfsd.dump.XXXXXX.
123
124       -P password-file
125              Read the user-name, user-id, and home directory information from
126              the file password-file.  Normally, hlfsd will use getpwent(3) to
127              read the password database.  This option allows you to  override
128              the  default  database,  and is useful if you want to map users'
129              mail files to a directory other than their home directory.  Only
130              the  username,  uid, and home-directory fields of the file pass‐
131              word-file are read and checked.  All other fields  are  ignored.
132              The  file  password-file  must  otherwise be compliant with Unix
133              System 7 colon-delimited format passwd(4).
134

FILES

136       /hlfs
137            directory under which hlfsd mounts itself and manages the symbolic
138            link home.
139
140       .hlfsdir
141            default  sub-directory  in the user's home directory, to which the
142            home symbolic link returned by hlfsd points.
143
144       /var/hlfs
145            directory to which home symbolic link returned by hlfsd points  if
146            it  is unable to verify the that user's home directory is accessi‐
147            ble.
148

SEE ALSO

150       amd(8), automount(8), cron(8), getgrent(3), getpwent(3), mail(1),  mnt‐
151       tab(4), mount(8), mtab(5), passwd(4), sendmail(8), umount(8).
152
153       HLFSD:  Delivering  Email  to  Your  $HOME,  in Proc. LISA-VII, The 7th
154       Usenix System Administration Conference, November 1993.
155
156       ``am-utils'' info(1) entry.
157
158       Linux  NFS  and  Automounter  Administration  by   Erez   Zadok,   ISBN
159       0-7821-2739-8, (Sybex, 2001).
160
161       http://www.am-utils.org
162

AUTHORS

164       Erez  Zadok  <ezk@cs.sunysb.edu>,  Computer  Science  Department, Stony
165       Brook University, Stony Brook, New  York,  USA.   and  Alexander  Dupuy
166       <dupuy@smarts.com>,  System  Management  ARTS,  White Plains, New York,
167       USA.
168
169       Other authors and contributors to am-utils are listed  in  the  AUTHORS
170       file distributed with am-utils.
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174                               14 September 1993                      HLFSD(8)
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