.\" t
.TH AUTOFS 5 "9 Feb 2014"
.SH NAME
autofs \- Format of the automounter maps
.SH "DESCRIPTION"
The automounter maps are FILE, NIS, NISPLUS or LDAP (including LDAP via SSS)
referred to by the master map of the automounter (see
.BR auto.master (5)).
These maps describe how file systems below the mount point of the map
(given in the master map) are to be mounted.  This page describes the
.B sun
map format; if another map format, other than
.B amd ,
is specified (e.g. \fBhesiod\fP),
this documentation does not apply.

Indirect maps, except for the internal hosts map, can be changed on the fly
and the automouter will recognize those changes on the next operation it
performs on that map. Direct maps require a HUP signal be sent to the
daemon to refresh their contents as does the master map.
.SH "SUN FORMAT"
This is a description of the text file format.  Other methods of specifying
these files may exist.  All empty lines or lines beginning with # are
ignored. The basic format of one line in such maps is:
.P
.BR key\  [ \-options ]\  location
.TP
.B key
.br
For indirect mounts this is the part of the path name between the mount point
and the path into the filesystem when it is mounted. Usually you can think about the
key as a sub-directory name below the autofs managed mount point.

For direct mounts this is the full path of each mount point. This map is always
associated with the /- mount point in the master map. 
.TP
.B options
.br
Zero or more options may be given.  Options can also be given in the 
.B auto.master
file in which case both values are cumulative (this is a difference
from SunOS).  The options are a list of comma separated options as
customary for the
.BR mount (8)
command.

There are several special options
.RS
.TP
.B \-fstype=
.br
is used to specify a filesystem type if the filesystem is not of the default
NFS type.  This option is processed by the automounter and not by the mount
command.
.TP
.B \-strict
.br
is used to treat errors when mounting file systems as fatal. This is important when
multiple file systems should be mounted (`multi-mounts'). If this option
is given, no file system is mounted at all if at least one file system
can't be mounted.
.TP
.B \-use-weight-only
.br
is used to make the weight the sole factor in selecting a server when multiple
servers are present in a map entry.
and
.TP
.B \-no-use-weight-only
.br
can be used to negate the option if it is present in the master map entry
for the map but is not wanted for the given mount.
.RE
.TP
.B location
The location specifies from where the file system is to be mounted.  In the
most cases this will be an NFS volume and the usual notation
.I host:pathname
is used to indicate the remote filesystem and path to be mounted.  If
the filesystem to be mounted begins with a / (such as local
.I /dev
entries or smbfs shares) a : needs to be prefixed (e.g. 
.IR :/dev/sda1 ).
.SH EXAMPLE
Indirect map:
.sp
.RS +.2i
.ta 1.0i 3.0i
.nf
kernel	\-ro,soft,intr	ftp.kernel.org:/pub/linux
boot	\-fstype=ext2	:/dev/hda1
windoze	\-fstype=smbfs	://windoze/c
removable	\-fstype=ext2	:/dev/hdd
cd	\-fstype=iso9660,ro	:/dev/hdc
floppy	\-fstype=auto	:/dev/fd0
server	\-rw,hard,intr	/ \-ro myserver.me.org:/ \\
			/usr myserver.me.org:/usr \\
			/home myserver.me.org:/home
.fi
.RE
.sp
In the first line we have a NFS remote mount of the kernel directory on
.IR ftp.kernel.org .
This is mounted read-only.  The second line mounts an ext2 volume from a
local ide drive.  The third makes a share exported from a Windows
machine available for automounting.  The rest should be fairly
self-explanatory. The last entry (the last three lines) is an example
of a multi-map (see below).

If you use the automounter for a filesystem without access permissions
(like \fBvfat\fP), users usually can't write on such a filesystem
because it is mounted as user \fBroot\fP.
You can solve this problem by passing the option \fIgid=<gid>\fP,
e.g. \fIgid=floppy\fP. The filesystem is then mounted as group
\fBfloppy\fP instead of \fBroot\fP. Then you can add the users
to this group, and they can write to the filesystem. Here's an
example entry for an autofs map:
.sp
.RS +.2i
.ta 1.0i 3.0i
.nf
floppy-vfat  \-fstype=vfat,sync,gid=floppy,umask=002  :/dev/fd0
.fi
.RE
.sp
Direct map:
.sp
.RS +.2i
.ta 1.0i 3.0i
.nf
/nfs/apps/mozilla	bogus:/usr/local/moxill
/nfs/data/budgets	tiger:/usr/local/budgets
/tst/sbin		bogus:/usr/sbin
.fi
.RE
.sp
.SH FEATURES
.SS Map Key Substitution
An & character in the
.B location
is expanded to the value of the 
.B key
field that matched the line (which probably only makes sense together with
a wildcard key).
.SS Wildcard Key
A map key of * denotes a wild-card entry. This entry is consulted
if the specified key does not exist in the map.  A typical wild-card
entry looks like this:
.sp
.RS +.2i
.ta 1.0i
.nf
*	server:/export/home/&
.fi
.RE
.sp
The special character '&' will be replaced by the provided key.  So,
in the example above, a lookup for the key 'foo' would yield a mount
of server:/export/home/foo.
.SS Variable Substitution
The following special variables will be substituted in the location
field of an automounter map entry if prefixed with $ as customary
from shell scripts (curly braces can be used to separate the field
name):
.sp
.RS +.2i
.ta 1.5i
.nf
ARCH	Architecture (uname \-m)
CPU	Processor Type
HOST	Hostname (uname \-n)
OSNAME	Operating System (uname \-s)
OSREL	Release of OS (uname \-r)
OSVERS	Version of OS (uname \-v)
.fi
.RE
.sp
autofs provides additional variables that are set based on the
user requesting the mount:
.sp 
.RS +.2i
.ta 1.5i
.nf
USER	The user login name
UID	The user login ID
GROUP	The user group name
GID	The user group ID
HOME	The user home directory
SHOST	Short hostname (domain part removed if present)
.fi
.RE
.sp
If a program map is used these standard environment variables will have
a prefix of "AUTOFS_" to prevent interpreted languages like python from
being able to load and execute arbitray code from a user home directory.
.RE
.sp
Additional entries can be defined with the \-Dvariable=Value map-option to
.BR automount (8).
.SS Executable Maps
A map can be marked as executable. A
.B program
map will be called with the key as an argument.  It may
return no lines of output if there's an error, or one or more lines
containing a map entry (with \\ quoting line breaks). The map entry
corresponds to what would normally follow a map key.
.P
An executable map can return an error code to indicate the failure in addition
to no output at all.  All output sent to stderr is logged into the system
logs.
.SS Multiple Mounts
A
.B multi-mount map
can be used to name multiple filesystems to mount.  It takes the form:
.sp
.RS +.2i
.ta 1.0i
.nf
.BI "key [ \-options ] [[/] location [/relative-mount-point [ \-options ] location...]..."
.fi
.RE
.sp
.P
This may extend over multiple lines, quoting the line-breaks with \`\\\'.
If present, the per-mountpoint mount-options are appended to the
default mount-options. This behaviour may be overridden by the append_options
configuration setting.
.SS Replicated Server
A mount location can specify multiple hosts for a location, portentially
with a different export path for the same file system. Historically these
different locations are read-only and provide the same replicated file system.
.sp
.RS +.2i
.ta 1.5i
.nf
Multiple replicated hosts, same path:
<path> host1,host2,hostn:/path/path

Multiple hosts, some with same path, some with another
<path> host1,host2:/blah host3:/some/other/path

Multiple replicated hosts, different (potentially) paths:
<path> host1:/path/pathA host2:/path/pathB

Mutliple weighted, replicated hosts same path:
<path> host1(5),host2(6),host3(1):/path/path

Multiple weighted, replicated hosts different (potentially) paths:
<path> host1(3):/path/pathA host2(5):/path/pathB

Anything else is questionable and unsupported, but these variations will also work:
<path> host1(3),host:/blah
.fi
.RE
.SH UNSUPPORTED
This version of the automounter supports direct maps stored in FILE, NIS, NISPLUS
and LDAP (including LDAP via SSS) only.
.P
.SH "AMD FORMAT"
This is a description of the text file format. Other methods of specifying
mount map entries may be required for different map sources.  All empty
lines or lines beginning with # are ignored. The basic format of one
line in such maps is:
.P
.BR key\ location-list
.TP
.B key
.br
A \fBkey\fP is a path (or a single path component alone) that may end
in the wildcard key, "*", or the wildcard key alone and must not begin
with the "/" character.
.TP
.B location-list
Following the \fBkey\fP is a mount \fBlocation-list\fP.
.TP
A \fBlocation-list\fP list has the following syntax:
.TP
.B location[\ location[\ ...\ ]]\ [||\ location[\ location[\ ...\ ]]
.P
A mount \fBlocation-list\fP can use the cut operator, \fB||\fP, to specify
locations that should be tried if none of the locations to the left of it
where selected for a mount attempt.

A mount \fBlocation\fP consists of an optional colon separated list
of \fBselectors\fP, followed by a colon separated list of \fBoption:=value\fP
pairs.

The \fBselectors\fP that may be used return a value or boolean result.
Those that return a value may be to used with the comparison
operators \fB==\fP and \fB!=\fP and those that return a boolean result
may be negated with the \fB!\fP.

For a \fBlocation\fP to be selected for a mount attempt all of its \fBselectors\fP
must evaluate to true. If a \fBlocation\fP is selected for a mount attempt
and succeeds the lookup is completed and returns success. If the mount
attempt fails the proceedure continues with the next \fBlocation\fP until
they have all been tried.

In addition some \fBselectors\fP take no argumenets, some one argument
and others optionally take two arguments.

The \fBselectors\fP that take no arguments are:
.RS
.TP
.B arch
.br
The machine architecture which, if not set in the confugration, is
obtained using uname(2).
.TP
.B karch
.br
The machine kernel architecture which, if not set in the confugration,
is obtained using uname(2).
.TP
.B os
.br
The operating system name, if not set in the confugration, is obtained
using uname(2).
.TP
.B osver
.br
The operating system version, if not set in the confugration, is obtained
using uname(2).
.TP
.B full_os
.br
The full operating system name, if not set in the confugration this selector
has no value.
.TP
.B vendor
.br
The operating system vendor name, if not set in the confugration this selector
has the value "unknown".
.TP
.B byte
.br
The endianness of the hardware.
.TP
.B cluster
.br
The name of the local cluster. It has a value only if it is set in the
configuration.
.TP
.B autodir
.br
The base path under which external mounts are done if they are needed.
Most mounts are done in place but some can't be and this is the base
path under which those mounts will be done.
.TP
.B domain
.br
The local domain name. It is set to the value of the configuration
option \fBsub_domain\fP. If sub_domain is not given in the configuration
it is set to the domain part of the local host name, as given by
gethostname(2).
.TP
.B host
.br
The local host name, without the domain part, as given by gethostname(2).
.TP
.B hostd
.br
The full host name. If \fBsub_domain\fP is given in the configuration
this is set to the contatenation of \fBhost\fP and \fBsub_domain\fP deperated
by a \fB.\fP. If \fBsub_domain\fP is not set in the configuration the value
of \fBdomain\fP is used instead of \fBsub_domain\fP.
.TP
.B uid
.br
The numeric value of the uid of the user that first requested the mount. Note
this is usual the same as that used by amd but can be different within autofs.
.TP
.B gid
.br
The numeric value of the gid of the user that first requested the mount. Note
this is usual the same as that used by amd but can be different within autofs.
.TP
.B key
.br
The string value of the key being looked up.
.TP
.B map
.br
The string value of the map name used to lookup \fBkey\fPs.
.TP
.B path
.br
The string value of the full path to the mount being requested.
.TP
.B dollar
.br
Evaluates to the string "$".
.RE
.TP
The \fBselectors\fP that take one argument are:
.RS
.TP
.B in_network(network) ", " network(network) ", " netnumber(network) ", " wire(network)
.br
These \fBselectors\fP are all the same. \fBin_network()\fP is the
preferred usage. The \fBnetwork\fP argument is an address (which may include
a subnet mask) or network name. The function compares \fBnetwork\fP
against each interface and returns true if \fBnetwork\fP belongs to
the network the interface is connected to.
.TP
.B xhost(hostname)
.br
The \fBxhost()\fP selector compares \fBhostname\fP to the \fB${host}\fP
and if it doesn't match it attempts to lookup the cannonical name
of \fBhostname\fP and compares it to \f${host}\fP as well.
.TP
.B exists(filename)
.br
Returns true if \fBfilename\fP exits as determined by lstat(2).
.TP
.B true()
.br
Evaluates to true, the argument is ignored and may be empty.
.TP
.B false()
.br
Evaluates to false, the argument is ignored and may be empty.
.RE
.TP
The \fBselectors\fP that take up to two arguments are:
.RS
.TP
.B netgrp(netgroup[,hostname])
.br
The \fBnetgrp()\fP selector returns true if \fPhostname\fP is a member of
the netgroup \fBnetgroup\fP. If \fBhostname\fP is not given \fB${host}\fP
is used for the comparison.
.TP
.B netgrpd(netgroup[,hostname])
.br
The \fBnetgrpd()i\fP selector behaves the same as \fBnetgrp()\fP except
that if \fBhostname\fP is not given \fB${hostd}\fP, the fully qualified
hostname, is used instead of \fB${host}\fP.
.RE
.TP
The \fBoptions\fP that may be used are:
.RS
.TP
.B type
.br
This is the mount filesystem \fBtype\fP.
It can have a value of
.BR auto ", " link ", " linkx ", " host ", " lofs ", " ext2-4 ", "
.BR xfs ", " nfs ", " nfsl " or " cdfs "."
Other types that are not yet implemented or are not available in autofs are
.BR nfsx ", " lustre ", " jfs ", " program ", " cachefs " and " direct "."
.TP
.B maptype
.br
The \fBmaptype\fP option specifies the type of the map source and can
have a value of \fBfile\fP, \fBnis\fP, \fBnisplus\fP, \fBexec\fP, \fBldap\fP
or \fBhesiod\fP. Map sources either not yet implemented or not available in
autofs are \fBsss\fP, \fBndbm\fP, \fBpasswd\fP and \fBunion\fP.
.TP
.B fs
.br
The option \fBfs\fP is used to specify the local filesystem. The meaning of
this option (and whether or not it is used) is dependent on the mount
filesystem \fBtype\fP.
.TP
.B rhost
.br
The remote host name for network mount requests.
.TP
.B rfs
.br
The remote host filesystem path for network mount requests.
.TP
.B dev
.br
Must resolve to the device file for local device mount
requests.
.TP
.B sublink
.br
The \fBsublink\fP option is used to specify a subdirectory
within the mount location to which this entry will point.
.TP
.B pref
.br
The \fBpref\fP option is used to specify a prefix that is
prepended to the lookup key before looking up the map entry
key.
.TP
.B opts
.br
The \fBopts\fP option is used to specify mount options to be
used for the mount. If a "\fB-\fP" is given it is ignored.
Options that may be used are dependend on the mount filesystem.
.TP
.B addopts
.br
The \fBaddopts\fP option is used to specify additional mount
options used in addition to the default mount options for the
mount location.
.TP
.B remopts
.br
The \fBaddopts\fP option is used to specify mount options used
instead the options given in \fBopts\fP when the mount location
is on a remote retwork.
.RE
.TP
A number of \fBoptions\fP aren't available or aren't yet implemented
within autofs, these are:
.RS
.TP
.B cache
.br
The \fBcache option\fP isn't used by autofs. The map entry cache is
continually updated and stale entries cleaned on re-load when map
changes are detected so these configuration entries are not used.
The \fBregex\fP map key matching is not implemented and may not be
due to the potential overhead of the full map scans needed on every
key lookup.
.TP
.B cachedir
.br
The \fBcachefs\fP filesystem is not available on Linux, a different
implementation is used for caching network mounted file systems.
.TP
.B mount ", " unmount ", " umount
.br
These \fBoptions\fP are used by the amd \fBprogram\fP mount type which
is not yet implemented.
.TP
.B delay
.br
This \fBoption\fP is not used by the autofs implementation and is ignored.
.RE
.BR
.SH FEATURES
.SS Key Matching
The amd parser key matching is unusual.

The key string to be looked up is constructed by prepending the prefix, if
there is one.

The resulting relative path string is matched by first trying the sting
itself. If no match is found the last component of the key string is
replaced with the wilcard match cahracter ("*") and a wildcard match is
attemted. This process continues until a match is found or until the
last match, against the wilcard match key alone, fails to match a map
entry and the key lookup fails.
.SS Macro Usage
Macros are used a lot in the autofs amd implementation.

Many of the option values are set as macro variables corresponding to the
option name during the map entry parse. So they may be used in subsequent
option values. Beware though, the order in which option values is not
necessarily left to right so you may get unexpected results.
.BR
.SH EXAMPLE
Example NFS mount map:
.P
Assuming we have the autofs master map entry:
.sp
.RS +.2i
.ta 1.0i 3.0i
.nf
/test	file,amd:/etc/amd.test
.fi
.RE
.sp
And the following map in /etc/amd.test:
.sp
.RS +.2i
.ta 1.0i 3.0i
.nf
/defaults	type:=nfs;rhost:=bilbo
apps	rfs:=/autofs
util	rhost:=zeus;rfs:=/work/util
local	rfs:=/shared;sublink:=local
.fi
.RE
.sp
In the first line we have an NFS remote mount of the exported directory
/autofs from host bilbo which would be mounted on /test/apps. Next
another nfs mount for the exported directory /work/util from host zeus.
This would be mounted on /test/util.

Finally we have an example of the use of the \fBsublink\fP option. In
this case the filesystem bilbo:/shared would be mounted on a path
external the automount directory (under the direcory given by
configuration option auto_dir) and the path /test/local either
symlinked or bind mounted (depending on the setting autofs_use_lofs)
to the "local" subdirectory of the external mount.
.BR
.SH "NOTES"
To be able to use IPv6 within autofs maps the package must be build
to use the libtirpc library for its RPC communications. This is
becuase the glibc RPC implementation doesn't support IPv6 and is
depricated so this is not likely to change.
.BR
.SH "SEE ALSO"
.BR automount (8),
.BR auto.master (5),
.BR autofs (8),
.BR autofs.conf (5),
.BR mount (8),
.BR autofs_ldap_auth.conf (5).
.SH AUTHOR
This manual page was written by Christoph Lameter <chris@waterf.org>,
for the Debian GNU/Linux system.  Edited by H. Peter Avian
<hpa@transmeta.com>, Jeremy Fitzhardinge <jeremy@goop.org> and
Ian Kent <raven@themaw.net>.