AUTOMASTER(5) BSD File Formats Manual AUTOMASTER(5)

NAME
     aauuttoommaasstteerr - automounter master map

DESCRIPTION
     The aauuttoommaasstteerr file contains a list of the directories that are to be
     automounted.  Associated with each directory is the name of a map that
     lists the locations of the filesystems to be automounted there.  The
     default map looks like this:

           #
           # Automounter master map
           #
           +automaster            # Use directory service
           /net                    -hosts          -nobrowse,nosuid
           /home                   autohome       -nobrowse
           /Network/Servers        -fstab
           /-                      -static

     A ``#'' is the comment character. All characters from it to the end of
     line are ignored.  A line beginning with ``+'' and followed by a name,
     indicates the name of a file or map accessible from a Directory Service
     source such as NIS or LDAP; the master map entries in that file or map
     are included at this point in the master map.  A line that specifies a
     map to be mounted has the format:

           mountpoint map -options

     where mountpoint is the directory on which the map is to be mounted, map
     is the name of the map to be mounted, and options is an optional, comma-
     separated list of default mount options to be used by any entries in the
     map that do not have their own mount options.  The nnoobbrroowwssee option is
     used on maps that have the potential to produce entries too numerous for
     browsing to be practical. This option as used in the master map is dis-
     tinct from nobrowse used as a Mac OS X mount option, which affects the
     visibility of the mount to the Finder.

     A map name beginning with / is the pathname of a file containing the map,
     otherwise the name represents a map to be found as a file in /etc or to
     be read from Directory Service (and thus from whatever sources Directory
     Service uses, such as NIS or LDAP servers).

     Note that, in order to get automounter maps from NIS, the "BSD Flat File
     and NIS" plugin must, in the Directory Utility application, be enabled
     and configured to "Use NIS domain for authentication".

     If more than one entry in the master map has the same mountpoint then all
     but the first are ignored.  For instance, in the following master map:

                   /shared         myautoshared
                   +automaster

     The /shared entry overrides any /shared specification imported from the
     network aauuttoommaasstteerr.

AAUUTTOOMMOOUUNNTTEERR MMAAPPSS
     Automounter maps associate directories with the locations of filesystems
     that are to be mounted when the directory is accessed.  Map entries have
     the general form:

           key location

     These map entries may be represented by lines in a file, NIS or LDAP
     tables indexed by the key, or from output of an executable map.  Most
     commonly, the location is simply the name of an NFS server and the path
     to an exported file system, e.g.

          local     mynfs:/export/local

     A location can also represent multiple mounts, where each is associated
     with a relative path, for example:

           pkg     \
                   /data   mynfs:/export/pkg/data \
                   /bin    mynfs:/export/pkg/bin  \
                   /man    mynfs:/export/pkg/man

     Reference to this entry will provide access to any of three exported file
     systems from the server, each via its own subdirectory.  Each of these
     sub-mounts will be done only when referenced.  Note the use of a back-
     slash to escape the newline so that the automounter will read these lines
     as a single map entry.

     The location can be preceded by a comma-separated list of mount options
     with a prepended ``-''.  For example:

             bin     -ro,nosuid  mynfs:/export/bin

DDiirreecctt MMaapp
     A direct map associates filesystem locations directly with directories.
     The entry key is the full path name of a directory.  For example:

           /usr/local      eng4:/export/local
           /src            eng4:/export/src

     Since the direct map as a whole isn't associated with a single directory,
     it is specified in the master map with a dummy directory name of /-.

IInnddiirreecctt MMaapp
     An indirect map is used where a large number of entries are to be associ-
     ated with a single directory.  Each map entry key is the simple name of a
     directory entry.  A good example of this is the autohome map which
     determines the entries under the /home directory.  For example:

           bill    argon:/export/home/bill
           brent   depot:/export/home/brent
           guy     depot:/export/home/guy

EExxeeccuuttaabbllee MMaapp
     An executable map is an indirect map represented by a file that has its
     execute bit set.  Instead of reading entries from the file directly, the
     automounter executes the program or script passing the key as an argument
     and receiving the location string on stdout.  If the automounter needs to
     enumerate map keys for a directory listing, it invokes the map with no
     arguments and expects a newline-separated list of keys on stdout.

     If an error occurs, the executable map must return a non-zero exit status
     and no output.

     For example, a map that, when bound to an Open Directory server, has one
     entry for every user, with the key being the user's login name and the
     entry being the URL of the user's home directory, could be implemented as

           #!/bin/sh
           if [ $# = 0 ]; then # List keys
                   dscl /Search -list Users
                   exit
           fi
           # Return location
           homedirloc=`dscl /Search -read Users/$1 HomeDirectory`
           case "$homedirloc" in

           "No such key: HomeDirectory"*)
                   homedirloc=`dscl /Search -read Users/$1 NFSHomeDirectory`
                   case "$homedirloc" in

                   "NFSHomeDirectory: /Network/Servers/"*)
                           #
                           # NFS home directory
                           #
                           echo "$homedirloc" | sed 's;NFSHomeDirectory: /Network/Servers//]*/;1:/2;'
                           ;;

                   *)
                           #
                           # Unknown
                           #
                           exit 1
                           ;;
                   esac
                   ;;

           "HomeDirectory: smb://"*)
                   #
                   # SMB home directory
                   #
                   echo "$homedirloc" | sed -e 's;HomeDirectory: ;;' -e 's;;/;' -e 's;;;'
                   ;;

           *)
                   #
                   # Unknown
                   #
                   exit 1
                   ;;
           esac

     (this is a simplified example; it does not handle users who do not have a
     network home directory, but includes them in the directory listing).

SSppeecciiaall MMaappss
     The special maps have reserved names and are built into the automounter.

     -fstab        This map would normally be mounted on /Network/Servers.
                   The key is the host name of a server; the contents of the
                   map entry are generated from corresponding entries in
                   fstab(5) data (as provided by getfsent(3)) that have the
                   net option and that specify mounts from that server.  An
                   entry of the form

                        server:/path mountpoint fstype options 0 0

                   will be mounted in server/path under the mount point of the
                   -fstab map, using the specified fstype file system type and
                   the specified options.  The mountpoint is ignored.

     -hosts        This map would normally be mounted on /net.  The key is the
                   host name of an NFS server; the contents of the map are
                   generated from the list of file systems exported by that
                   server.  For example, a server that exports three NFS
                   filesystems might have an equivalent map entry of:

                         myserv  \
                                 /export/home    myserv:/export/home \
                                 /export/local   myserv:/export/local \
                                 /export/pkg     myserv:/export/pkg

                   To access the first mount, the path would be
                   /net/myserv/export/home if the map was associated with
                   /net.

     -null         This map has no entries.  It is used to disable entries
                   that occur later in the aauuttoommaasstteerr file.  For example:

                                 /shared         -null
                                 +automaster

                   The -null entry disables any /shared entry in +automaster.

     -static       This map is a direct map, so the mount point must be speci-
                   fied as /-.  The contents are generated from all entries in
                   fstab(5) data (as provided by getfsent(3)) that do not have
                   the net option.  An fstab(5) entry of the form

                           server:/path mountpoint fstype options rw 0 0

                   will generate a direct map entry of the form

                           mountpoint options server:/path

FILES     /etc/automaster  The master map file.

SEE ALSO
     automount(8), automountd(8), autofsd(8), autofs.conf(5), fstab(5),
     getfsent(3), DirectoryService(8)

Darwin                          April 20, 2007                          Darwin