xref: /freebsd/usr.sbin/autofs/auto_master.5 (revision 28f42739a547ffe0b5dfaaf9f49fb4c4813aa232)
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4.\" This software was developed by Edward Tomasz Napierala under sponsorship
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28.\" $FreeBSD$
29.\"
30.Dd November 22, 2014
31.Dt AUTO_MASTER 5
32.Os
33.Sh NAME
34.Nm auto_master
35.Nd auto_master and map file format
36.Sh DESCRIPTION
37The automounter configuration consists of the
38.Nm
39configuration file, which assigns filesystem paths to map names,
40and maps, which contain actual mount information.
41The
42.Nm
43configuration file is used by the
44.Xr automount 8
45command.
46Map files are read by the
47.Xr automountd 8
48daemon.
49.Sh AUTO_MASTER SYNTAX
50The
51.Nm
52file consists of lines with two or three entries separated by whitespace
53and terminated by newline character:
54.Bd -literal -offset indent
55.Pa mountpoint Pa map_name Op Ar -options
56.Ed
57.Pp
58.Pa mountpoint
59is either a fully specified path, or
60.Li /- .
61When
62.Pa mountpoint
63is a full path,
64.Pa map_name
65must reference an indirect map.
66Otherwise,
67.Pa map_name
68must reference a direct map.
69See
70.Sx "MAP SYNTAX" below.
71.Pp
72.Pa map_name
73specifies map to use.
74If
75.Pa map_name
76begins with
77.Li - ,
78it specifies a special map.
79See
80.Sx "MAP SYNTAX"
81below.
82If
83.Pa map_name
84is not a fully specified path
85.Pq it does not start with Li / ,
86.Xr automountd 8
87will search for that name in
88.Li /etc .
89Otherwise it will use the path as given.
90If the file indicated by
91.Pa map_name
92is executable,
93.Xr automountd 8
94will assume it is an executable map.
95See
96.Sx "MAP SYNTAX"
97below.
98Otherwise, the file is opened and the contents parsed.
99.Pp
100.Pa -options
101is an optional field that starts with
102.Li -
103and can contain generic filesystem mount options.
104.Pp
105The following example specifies that the /etc/auto_example indirect map
106will be mounted on /example.
107.Bd -literal -offset indent
108/example auto_example
109.Ed
110.Sh MAP SYNTAX
111Map files consist of lines with a number of entries separated by whitespace
112and terminated by newline character:
113.Bd -literal -offset indent
114.Pa key Oo Ar -options Oc Oo Ar mountpoint Oo -options Oc Oc Ar location Op ...
115.Ed
116.Pp
117In most cases, it can be simplified to:
118.Bd -literal -offset indent
119.Pa key Oo Ar -options Oc Ar location
120.Ed
121.Pp
122.Pa key
123is the path component used by
124.Xr automountd 8
125to find the right map entry to use.
126It is also used to form the final mountpoint.
127A wildcard
128.Pq Ql *
129can be used for the key.
130It matches every directory that does not match other keys.
131Those directories will not be visible to the user
132until accessed.
133.Pp
134The
135.Ar options
136field, if present, must begin with
137.Li - .
138When mounting the filesystem, options supplied to
139.Nm
140and options specified in the map entry are concatenated together.
141The special option
142.Li fstype
143is used to specify filesystem type.
144It is not passed to the mount program as an option.
145Instead, it is passed as an argument to
146.Cm "mount -t".
147The default
148.Li fstype
149is
150.Ql nfs .
151The special option
152.Li nobrowse
153is used to disable creation of top-level directories for special
154and executable maps.
155.Pp
156The optional
157.Pa mountpoint
158field is used to specify multiple mount points
159for a single key.
160.Pp
161The
162.Ar location
163field specifies the filesystem to be mounted.
164Ampersands
165.Pq Ql &
166in the
167.Ar location
168field are replaced with the value of
169.Ar key .
170This is typically used with wildcards, like:
171.Bd -literal -offset indent
172.Li *	192.168.1.1:/share/&
173.Ed
174.Pp
175To pass a location that begins with
176.Li / ,
177prefix it with a colon.
178For example,
179.Li :/dev/cd0 .
180.Pp
181This example, when put into
182.Pa /etc/auto_example ,
183and with
184.Nm
185referring to the map as described above, specifies that the NFS share
186.Li 192.168.1.1:/share/example/x
187will be mounted on
188.Pa /example/x/
189when any process attempts to access that mountpoint, with
190.Li intr
191and
192.Li nfsv4
193mount options, described in
194.Xr mount_nfs 8 :
195.Bd -literal -offset indent
196.Li x -intr,nfsv4 192.168.1.1:/share/example/x
197.Ed
198.Pp
199Automatically mount an SMB share on access, as a guest user,
200without prompting for a password:
201.Bd -literal -offset indent
202.Li share -fstype=smbfs,-N ://@server/share
203.Ed
204.Pp
205Automatically mount the CD drive on access:
206.Bd -literal -offset indent
207.Li cd -fstype=cd9660 :/dev/cd0
208.Ed
209.Sh SPECIAL MAPS
210Special maps have names beginning with
211.Li - .
212Supported special maps are:
213.Pp
214.Bl -tag -width "-hosts" -compact
215.It Li -hosts
216Query the remote NFS server and map exported shares.
217This map is traditionally mounted on
218.Pa /net .
219Access to files on a remote NFS server is provided through the
220.Pa /net/nfs-server-ip/share-name/
221directory without any additional configuration.
222.It Li -media
223Query devices that are not yet mounted, but contain valid filesystems.
224Generally used to access files on removable media.
225.It Li -null
226Prevent
227.Xr automountd 8
228from mounting anything on the mountpoint.
229.El
230.Sh EXECUTABLE MAPS
231If the map file specified in
232.Nm
233has execute bit set, the
234.Xr automountd 8
235will execute it and parse the standard output instead of parsing
236the file contents.
237.Sh INDIRECT VERSUS DIRECT MAPS
238Indirect maps are referred to in
239.Nm
240by entries with a fully qualified path as a mount point, and must contain only
241relative paths as keys.
242Direct maps are referred to in
243.Nm
244by entries with
245.Li /-
246as the mountpoint, and must contain only fully qualified paths as keys.
247For indirect maps, the final mount point is determined by concatenating the
248.Nm
249mountpoint with the map entry key and optional map entry mountpoint.
250For direct maps, the final mount point is determined by concatenating
251the map entry key with the optional map entry mountpoint.
252.Pp
253The example above could be rewritten using direct map, by placing this in
254.Nm :
255.Bd -literal -offset indent
256.Li /- auto_example
257.Ed
258.Pp
259and this in
260.Li /etc/auto_example
261map file:
262.Bd -literal -offset indent
263.Li /example/x -intr,nfsv4 192.168.1.1:/share/example/x
264.Li /example/share -fstype=smbfs,-N ://@server/share
265.Li /example/cd -fstype=cd9660 :/dev/cd0
266.Ed
267.Sh DIRECTORY SERVICES
268Both
269.Nm
270and maps may contain entries consisting of a plus sign and map name:
271.Bd -literal -offset indent
272.Li +auto_master
273.Ed
274.Pp
275Those entries cause
276.Xr automountd 8
277daemon to retrieve the named map from directory services (like LDAP)
278and include it where the entry was.
279.Pp
280If the file containing the map referenced in
281.Nm
282is not found, the map will be retrieved from directory services instead.
283.Pp
284To retrieve entries from directory services,
285.Xr automountd 8
286daemon runs
287.Pa /etc/autofs/include ,
288which is usually a shell script, with map name as the only command line
289parameter.
290The script should output entries formatted according to
291.Nm
292or automounter map syntax to standard output.
293An example script to use LDAP is included in
294.Pa /etc/autofs/include_ldap .
295It can be symlinked to
296.Pa /etc/autofs/include .
297.Sh FILES
298.Bl -tag -width ".Pa /etc/auto_master" -compact
299.It Pa /etc/auto_master
300The default location of the
301.Pa auto_master
302file.
303.El
304.Sh SEE ALSO
305.Xr autofs 5 ,
306.Xr automount 8 ,
307.Xr automountd 8 ,
308.Xr autounmountd 8
309.Sh AUTHORS
310The
311.Nm
312configuration file functionality was developed by
313.An Edward Tomasz Napierala Aq Mt trasz@FreeBSD.org
314under sponsorship from the FreeBSD Foundation.
315