xref: /freebsd/share/man/man8/nanobsd.8 (revision f856af0466c076beef4ea9b15d088e1119a945b8)
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25.\" $FreeBSD$
26.\"
27.Dd August 28, 2006
28.Dt NANOBSD 8
29.Os
30.Sh NAME
31.Nm nanobsd.sh
32.Nd utility used to create a FreeBSD system image suitable for embedded
33applications
34.Sh SYNOPSIS
35.Nm
36.Op Fl bhkw
37.Op Fl c Ar config-file
38.Sh DESCRIPTION
39The
40.Nm
41utility is a script which produces a minimal implementation of
42.Fx
43(called
44.Nm NanoBSD ) ,
45which typically fits on a small media such as a Compact Flash card,
46or other mass storage medium.
47It can be used to build specialized install images, designed for easy
48installation and maintenance.
49.Pp
50The following options are available:
51.Bl -tag -width ".Fl c Ar config-file" -offset indent
52.It Fl b
53Skip the build stages (both for kernel and world).
54.It Fl c Ar config-file
55Specify the configuration file to use.
56.It Fl h
57Display usage information.
58.It Fl k
59Skip the
60.Cm buildkernel
61stage of the build.
62.It Fl w
63Skip the
64.Cm buildworld
65stage of the build.
66.El
67.Pp
68The features of
69.Nm NanoBSD
70include:
71.Pp
72.Bl -bullet -offset indent -compact
73.It
74Ports and packages work as in
75.Fx .
76Every single application can be installed and used in a
77.Nm NanoBSD
78image, the same way as in
79.Fx .
80.It
81No missing functionality.
82If it is possible to do something with
83.Fx ,
84it is possible to do the same thing with
85.Nm NanoBSD ,
86unless the specific feature or features were explicitly removed from the
87.Nm NanoBSD
88image when it was created.
89.It
90Everything is read-only at run-time.
91It is safe to pull the power-plug.
92There is no necessity to run
93.Xr fsck 8
94after a non-graceful shutdown of the system.
95.It
96Easy to build and customize.
97Making use of just one shell script and one configuration file it is
98possible to build reduced and customized images satisfying any arbitrary
99set of requirements.
100.El
101.Ss Nm NanoBSD Ss Media Layout
102The mass storage medium is divided into three parts by default (which
103are normally mounted read-only):
104.Pp
105.Bl -bullet -offset indent -compact
106.It
107Two image partitions:
108.Li code#1
109and
110.Li code#2 .
111.It
112The configuration file partition, which can be mounted under the
113.Pa /cfg
114directory at run time.
115.El
116.Pp
117The
118.Pa /etc
119and
120.Pa /var
121directories are
122.Xr md 4
123(malloc backed) disks.
124.Pp
125The configuration file partition persists under the
126.Pa /cfg
127directory.
128It contains files for
129.Pa /etc
130directory and is briefly mounted read-only right after the system boot,
131therefore it is required to copy modified files from
132.Pa /etc
133back to the
134.Pa /cfg
135directory if changes are expected to persist after the system restarts.
136.Sh BUILDING Nm NanoBSD
137A
138.Nm NanoBSD
139image is built using a simple
140.Nm
141shell script, which can be
142found in the
143.Pa src/tools/tools/nanobsd
144directory.
145This script creates a bootable image, which can be copied on the storage
146medium using the
147.Xr dd 1
148utility.
149.Pp
150The necessary commands to build and install a
151.Nm NanoBSD
152image are:
153.Bd -literal -offset indent
154cd /usr/src/tools/tools/nanobsd
155sh nanobsd.sh
156cd /usr/obj/nanobsd.full
157dd if=_.disk.full of=/dev/da0 bs=64k
158.Ed
159.Sh CUSTOMIZING Nm NanoBSD
160This is probably the most important and most interesting feature of
161.Nm NanoBSD .
162This is also where you will be spending most of the time when developing with
163.Nm NanoBSD .
164.Pp
165Customization is done in two ways:
166.Pp
167.Bl -bullet -offset indent -compact
168.It
169Configuration options.
170.It
171Custom functions.
172.El
173.Pp
174With configuration settings, it is possible to configure options passed
175to both the
176.Cm buildworld
177and
178.Cm installworld
179stages of the
180.Nm NanoBSD
181build process, as well as internal options passed to the main build
182process of
183.Nm NanoBSD .
184Through these options it is possible to cut the system down, so it will
185fit on as little as 64MB.
186You can use the configuration options to trim down the system
187even more, until it will consist of just the kernel and two or three
188files in the userland.
189.Pp
190The configuration file consists of configuration options, which override
191the default values.
192The most important directives are:
193.Bl -tag -width ".Va CONF_INSTALL" -offset indent
194.It Va NANO_NAME
195Build name (used to construct the working directory names).
196.It Va NANO_SRC
197Path to the source tree used to build the image.
198.It Va NANO_KERNEL
199Name of the kernel configuration file used to build the kernel.
200.It Va CONF_BUILD
201Options passed to the
202.Cm buildworld
203stage of the build.
204.It Va CONF_INSTALL
205Options passed to the
206.Cm installworld
207stage of the build.
208.It Va CONF_WORLD
209Options passed to both the
210.Cm buildworld
211and
212.Cm installworld
213stages of the build.
214.It Va FlashDevice
215Defines the type of media to use.
216Check the
217.Pa FlashDevice.sub
218file for more details.
219.El
220.Pp
221For more configuration options, please check the
222.Nm
223script.
224.Pp
225To build
226.Nm NanoBSD
227image using the
228.Pa nanobsd.conf
229configuration file, use the following command:
230.Bd -literal -offset indent
231sh nanobsd.sh -c nanobsd.conf
232.Ed
233.Pp
234It is possible to fine-tune
235.Nm NanoBSD
236using shell functions in the configuration file.
237The following example illustrates the basic model of custom functions:
238.Bd -literal -offset indent
239cust_foo () (
240	echo "bar=topless" > \\
241	     ${NANO_WORLDDIR}/etc/foo
242)
243customize_cmd cust_foo
244.Ed
245.Pp
246There are a few pre-defined customization functions ready for use:
247.Bl -tag -width ".Cm cust_allow_ssh_root" -offset indent
248.It Cm cust_comconsole
249Disables
250.Xr getty 8
251on the virtual
252.Xr syscons 4
253terminals
254.Pq Pa /dev/ttyv*
255and enables the use of the first serial port as the system
256console.
257.It Cm cust_allow_ssh_root
258Allow root to log in via
259.Xr sshd 8 .
260.It Cm cust_install_files
261Installs files from the
262.Pa nanobsd/Files
263directory, which contains some useful scripts for system administration.
264.El
265.Sh FILES
266.Bl -tag -width ".Pa src/tools/tools/nanobsd" -compact
267.It Pa src/tools/tools/nanobsd
268Base directory of the
269.Nm NanoBSD
270build script.
271.El
272.Sh EXAMPLES
273Making persistent changes to
274.Pa /etc/resolv.conf :
275.Bd -literal -offset indent
276vi /etc/resolv.conf
277\&...
278mount /cfg
279cp /etc/resolv.conf /cfg
280umount /cfg
281.Ed
282.Pp
283A more useful example of a customization function is the following,
284which changes the default size of the
285.Pa /etc
286directory from 5MB to 30MB:
287.Bd -literal -offset indent
288cust_etc_size () (
289	cd ${NANO_WORLDDIR}/conf
290	echo 30000 > default/etc/md_size
291)
292customize_cmd cust_etc_size
293.Ed
294.Sh SEE ALSO
295.Xr make.conf 5 ,
296.Xr picobsd 8
297.Sh HISTORY
298The
299.Nm
300utility first appeared in
301.Fx 6.0 .
302.Sh AUTHORS
303.An -nosplit
304.Nm NanoBSD
305was developed by
306.An Poul-Henning Kamp Aq phk@FreeBSD.org .
307This manual page was written by
308.An Daniel Gerzo Aq danger@FreeBSD.org .
309