xref: /freebsd/share/man/man8/nanobsd.8 (revision 7cc42f6d25ef2e19059d088fa7d4853fe9afefb5)
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25.\" $FreeBSD$
26.\"
27.Dd May 19, 2016
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 bfhiKknqvwX
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 f
57Skip the code slice extraction.
58.It Fl h
59Display usage information.
60.It Fl i
61Skip the disk image build stage.
62.It Fl K
63Skip the
64.Cm installkernel
65stage of the build.
66.It Fl k
67Skip the
68.Cm buildkernel
69stage of the build.
70.It Fl n
71Do not cleanup before each build stage.
72This suppresses the normal cleanup work done before the
73.Cm buildworld
74stage and adds -DNO_CLEAN to the make command line
75used for each build stage (world and kernel).
76.It Fl q
77Make output more quiet.
78.It Fl v
79Make output more verbose.
80.It Fl w
81Skip the
82.Cm buildworld
83stage of the build.
84.It Fl X
85Make
86.Cm native-xtools.
87.El
88.Pp
89The features of
90.Nm NanoBSD
91include:
92.Pp
93.Bl -bullet -offset indent -compact
94.It
95Ports and packages work as in
96.Fx .
97Every single application can be installed and used in a
98.Nm NanoBSD
99image, the same way as in
100.Fx .
101.It
102No missing functionality.
103If it is possible to do something with
104.Fx ,
105it is possible to do the same thing with
106.Nm NanoBSD ,
107unless the specific feature or features were explicitly removed from the
108.Nm NanoBSD
109image when it was created.
110.It
111Everything is read-only at run-time.
112It is safe to pull the power-plug.
113There is no necessity to run
114.Xr fsck 8
115after a non-graceful shutdown of the system.
116.It
117Easy to build and customize.
118Making use of just one shell script and one configuration file it is
119possible to build reduced and customized images satisfying any arbitrary
120set of requirements.
121.El
122.Ss NanoBSD Media Layout
123The mass storage medium is divided into three parts by default (which
124are normally mounted read-only):
125.Pp
126.Bl -bullet -offset indent -compact
127.It
128Two image partitions:
129.Li code#1
130and
131.Li code#2 .
132.It
133The configuration file partition, which can be mounted under the
134.Pa /cfg
135directory at run time.
136.El
137.Pp
138The
139.Pa /etc
140and
141.Pa /var
142directories are
143.Xr md 4
144(malloc backed) disks.
145.Pp
146The configuration file partition persists under the
147.Pa /cfg
148directory.
149It contains files for
150.Pa /etc
151directory and is briefly mounted read-only right after the system boot,
152therefore it is required to copy modified files from
153.Pa /etc
154back to the
155.Pa /cfg
156directory if changes are expected to persist after the system restarts.
157.Sh BUILDING Nm NanoBSD
158A
159.Nm NanoBSD
160image is built using a simple
161.Nm
162shell script, which can be
163found in the
164.Pa src/tools/tools/nanobsd
165directory.
166This script creates a bootable image, which can be copied on the storage
167medium using the
168.Xr dd 1
169utility.
170.Pp
171The necessary commands to build and install a
172.Nm NanoBSD
173image are:
174.Bd -literal -offset indent
175cd /usr/src/tools/tools/nanobsd
176sh nanobsd.sh
177cd /usr/obj/nanobsd.full
178dd if=_.disk.full of=/dev/da0 bs=64k
179.Ed
180.Sh CUSTOMIZING Nm NanoBSD
181This is probably the most important and most interesting feature of
182.Nm NanoBSD .
183This is also where you will be spending most of the time when developing with
184.Nm NanoBSD .
185.Pp
186Customization is done in two ways:
187.Pp
188.Bl -bullet -offset indent -compact
189.It
190Configuration options.
191.It
192Custom functions.
193.El
194.Pp
195With configuration settings, it is possible to configure options passed
196to both the
197.Cm buildworld
198and
199.Cm installworld
200stages of the
201.Nm NanoBSD
202build process, as well as internal options passed to the main build
203process of
204.Nm NanoBSD .
205Through these options it is possible to cut the system down, so it will
206fit on as little as 64MB.
207You can use the configuration options to trim down the system
208even more, until it will consist of just the kernel and two or three
209files in the userland.
210.Pp
211The configuration file consists of configuration options, which override
212the default values.
213The most important directives are:
214.Bl -tag -width ".Va CONF_INSTALL" -offset indent
215.It Va NANO_NAME
216Build name (used to construct the working directory names).
217.It Va NANO_SRC
218Path to the source tree used to build the image.
219.It Va NANO_KERNEL
220Name of the kernel configuration file used to build the kernel.
221.It Va NANO_ARCH
222Machine processor architecture to build.
223Defaults to output of
224.Cm uname -p .
225.It Va NANO_BOOT0CFG
226Controls the options passed to
227.Xr boot0cfg 8 ;
228these dictate
229.Nm boot0 Ns 's
230behaviour.
231.It Va NANO_BOOTLOADER
232The
233.Nm boot0
234loader to use relative to the
235.Va NANO_WORLDDIR
236variable.
237This defaults to
238.Pa boot/boot0sio
239and should be overridden to
240.Pa boot/boot0
241to provide a VGA
242console.
243.It Va CONF_BUILD
244Options passed to the
245.Cm buildworld
246stage of the build.
247.It Va CONF_INSTALL
248Options passed to the
249.Cm installworld
250stage of the build.
251.It Va CONF_WORLD
252Options passed to both the
253.Cm buildworld
254and
255.Cm installworld
256stages of the build.
257.It Va FlashDevice
258Defines the type of media to use.
259Check the
260.Pa FlashDevice.sub
261file for more details.
262.El
263.Pp
264For more configuration options, please check the
265.Nm
266script.
267.Pp
268To build
269.Nm NanoBSD
270image using the
271.Pa nanobsd.conf
272configuration file, use the following command:
273.Bd -literal -offset indent
274sh nanobsd.sh -c nanobsd.conf
275.Ed
276.Pp
277It is possible to fine-tune
278.Nm NanoBSD
279using shell functions in the configuration file.
280The following example illustrates the basic model of custom functions:
281.Bd -literal -offset indent
282cust_foo () (
283	echo "bar=topless" > \\
284	     ${NANO_WORLDDIR}/etc/foo
285)
286customize_cmd cust_foo
287.Ed
288.Pp
289There are a few pre-defined customization functions ready for use:
290.Bl -tag -width ".Cm cust_allow_ssh_root" -offset indent
291.It Cm cust_comconsole
292Disables
293.Xr getty 8
294on the virtual
295.Xr syscons 4
296or
297.Xr vt 4
298terminals
299.Pq Pa /dev/ttyv*
300and enables the use of the first serial port as the system
301console.
302.It Cm cust_allow_ssh_root
303Allow root to log in via
304.Xr sshd 8 .
305.It Cm cust_install_files
306Installs files from the
307.Pa nanobsd/Files
308directory, which contains some useful scripts for system administration.
309.El
310.Sh FILES
311.Bl -tag -width ".Pa src/tools/tools/nanobsd" -compact
312.It Pa src/tools/tools/nanobsd
313Base directory of the
314.Nm NanoBSD
315build script.
316.El
317.Sh EXAMPLES
318Making persistent changes to
319.Pa /etc/resolv.conf :
320.Bd -literal -offset indent
321vi /etc/resolv.conf
322\&...
323mount /cfg
324cp /etc/resolv.conf /cfg
325umount /cfg
326.Ed
327.Pp
328A more useful example of a customization function is the following,
329which changes the default size of the
330.Pa /etc
331directory from 5MB to 30MB:
332.Bd -literal -offset indent
333cust_etc_size () (
334	cd ${NANO_WORLDDIR}/conf
335	echo 30000 > default/etc/md_size
336)
337customize_cmd cust_etc_size
338.Ed
339.Sh SEE ALSO
340.Xr make.conf 5 ,
341.Xr boot 8 ,
342.Xr boot0cfg 8
343.Sh HISTORY
344The
345.Nm
346utility first appeared in
347.Fx 6.0 .
348.Sh AUTHORS
349.An -nosplit
350.Nm NanoBSD
351was developed by
352.An Poul-Henning Kamp Aq Mt phk@FreeBSD.org .
353This manual page was written by
354.An Daniel Gerzo Aq Mt danger@FreeBSD.org .
355