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32 .Nd utility used to create a FreeBSD system image suitable for embedded
37 .Op Fl c Ar config-file
41 utility is a script which produces a minimal implementation of
45 which typically fits on a small media such as a Compact Flash card,
46 or other mass storage medium.
47 It can be used to build specialized install images, designed for easy
48 installation and maintenance.
50 The following options are available:
51 .Bl -tag -width ".Fl c Ar config-file" -offset indent
53 Skip the build stages (both for kernel and world).
54 .It Fl c Ar config-file
55 Specify the configuration file to use.
57 Display usage information.
72 .Bl -bullet -offset indent -compact
74 Ports and packages work as in
76 Every single application can be installed and used in a
78 image, the same way as in
81 No missing functionality.
82 If it is possible to do something with
84 it is possible to do the same thing with
86 unless the specific feature or features were explicitly removed from the
88 image when it was created.
90 Everything is read-only at run-time.
91 It is safe to pull the power-plug.
92 There is no necessity to run
94 after a non-graceful shutdown of the system.
96 Easy to build and customize.
97 Making use of just one shell script and one configuration file it is
98 possible to build reduced and customized images satisfying any arbitrary
101 .Ss Nm NanoBSD Ss Media Layout
102 The mass storage medium is divided into three parts by default (which
103 are normally mounted read-only):
105 .Bl -bullet -offset indent -compact
107 Two image partitions:
112 The configuration file partition, which can be mounted under the
114 directory at run time.
123 (malloc backed) disks.
125 The configuration file partition persists under the
128 It contains files for
130 directory and is briefly mounted read-only right after the system boot,
131 therefore it is required to copy modified files from
135 directory if changes are expected to persist after the system restarts.
136 .Sh BUILDING Nm NanoBSD
139 image is built using a simple
141 shell script, which can be
143 .Pa src/tools/tools/nanobsd
145 This script creates a bootable image, which can be copied on the storage
150 The necessary commands to build and install a
153 .Bd -literal -offset indent
154 cd /usr/src/tools/tools/nanobsd
156 cd /usr/obj/nanobsd.full
157 dd if=_.disk.full of=/dev/da0 bs=64k
159 .Sh CUSTOMIZING Nm NanoBSD
160 This is probably the most important and most interesting feature of
162 This is also where you will be spending most of the time when developing with
165 Customization is done in two ways:
167 .Bl -bullet -offset indent -compact
169 Configuration options.
174 With configuration settings, it is possible to configure options passed
181 build process, as well as internal options passed to the main build
184 Through these options it is possible to cut the system down, so it will
185 fit on as little as 64MB.
186 You can use the configuration options to trim down the system
187 even more, until it will consist of just the kernel and two or three
188 files in the userland.
190 The configuration file consists of configuration options, which override
192 The most important directives are:
193 .Bl -tag -width ".Va CONF_INSTALL" -offset indent
195 Build name (used to construct the working directory names).
197 Path to the source tree used to build the image.
199 Name of the kernel configuration file used to build the kernel.
201 Controls the options passed to
206 .It Va NANO_BOOTLOADER
209 loader to use relative to the
214 and should be overridden to
219 Options passed to the
223 Options passed to the
227 Options passed to both the
233 Defines the type of media to use.
236 file for more details.
239 For more configuration options, please check the
247 configuration file, use the following command:
248 .Bd -literal -offset indent
249 sh nanobsd.sh -c nanobsd.conf
252 It is possible to fine-tune
254 using shell functions in the configuration file.
255 The following example illustrates the basic model of custom functions:
256 .Bd -literal -offset indent
258 echo "bar=topless" > \\
259 ${NANO_WORLDDIR}/etc/foo
261 customize_cmd cust_foo
264 There are a few pre-defined customization functions ready for use:
265 .Bl -tag -width ".Cm cust_allow_ssh_root" -offset indent
266 .It Cm cust_comconsole
273 and enables the use of the first serial port as the system
275 .It Cm cust_allow_ssh_root
276 Allow root to log in via
278 .It Cm cust_install_files
279 Installs files from the
281 directory, which contains some useful scripts for system administration.
284 .Bl -tag -width ".Pa src/tools/tools/nanobsd" -compact
285 .It Pa src/tools/tools/nanobsd
286 Base directory of the
291 Making persistent changes to
292 .Pa /etc/resolv.conf :
293 .Bd -literal -offset indent
297 cp /etc/resolv.conf /cfg
301 A more useful example of a customization function is the following,
302 which changes the default size of the
304 directory from 5MB to 30MB:
305 .Bd -literal -offset indent
307 cd ${NANO_WORLDDIR}/conf
308 echo 30000 > default/etc/md_size
310 customize_cmd cust_etc_size
320 utility first appeared in
326 .An Poul-Henning Kamp Aq phk@FreeBSD.org .
327 This manual page was written by
328 .An Daniel Gerzo Aq danger@FreeBSD.org .