xref: /freebsd/usr.sbin/config/config.8 (revision 74bf4e164ba5851606a27d4feff27717452583e5)
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28.\"     @(#)config.8	8.2 (Berkeley) 4/19/94
29.\" $FreeBSD$
30.\"
31.Dd July 4, 2001
32.Dt CONFIG 8
33.Os
34.Sh NAME
35.Nm config
36.Nd build system configuration files
37.Sh SYNOPSIS
38.Nm
39.Op Fl gp
40.Op Fl d Ar destdir
41.Ar SYSTEM_NAME
42.Sh DESCRIPTION
43This is the old version of the
44.Nm
45utility.
46It understands the old autoconfiguration scheme
47used on the HP300, i386, DECstation, and derivative platforms.
48The new version of
49.Nm
50is used with the
51SPARC platform.
52Only the version of
53.Nm
54applicable to the architecture that you are running
55will be installed on your machine.
56.Pp
57The
58.Nm
59utility builds a set of system configuration files from the file
60.Ar SYSTEM_NAME
61which describes
62the system to configure.
63A second file
64tells
65.Nm
66what files are needed to generate a system and
67can be augmented by configuration specific set of files
68that give alternate files for a specific machine
69(see the
70.Sx FILES
71section below).
72.Pp
73Available options and operands:
74.Bl -tag -width ".Ar SYSTEM_NAME"
75.It Fl d Ar destdir
76Use
77.Ar destdir
78as the output directory, instead of the default one.
79Note that
80.Nm
81does not append
82.Ar SYSTEM_NAME
83to the directory given.
84.It Fl g
85Configure a system for debugging.
86.It Fl p
87Configure a system for profiling; for example,
88.Xr kgmon 8
89and
90.Xr gprof 1 .
91If two or more
92.Fl p
93options are supplied,
94.Nm
95configures a system for high resolution profiling.
96.It Ar SYSTEM_NAME
97Specify the name of the system configuration file
98containing device specifications, configuration options
99and other system parameters for one system configuration.
100.El
101.Pp
102The
103.Nm
104utility should be run from the
105.Pa conf
106subdirectory of the system source (usually
107.Pa /sys/ Ns Va ARCH Ns Pa /conf ) ,
108where
109.Va ARCH
110represents one of the architectures supported by
111.Fx .
112The
113.Nm
114utility creates the directory
115.Pa ../compile/ Ns Ar SYSTEM_NAME
116or the one given with the
117.Fl d
118option
119as necessary and places all output files there.
120The output of
121.Nm
122consists of a number of files; for the
123.Tn i386 ,
124they are:
125.Pa ioconf.c ,
126a description
127of what I/O devices are attached to the system;
128.Pa Makefile ,
129used by
130.Xr make 1
131in building the system;
132header files,
133definitions of
134the number of various devices that will be compiled into the system.
135.Pp
136After running
137.Nm ,
138it is necessary to run
139.Dq Li make depend
140in the directory where the new makefile
141was created.
142The
143.Nm
144utility prints a reminder of this when it completes.
145.Pp
146If any other error messages are produced by
147.Nm ,
148the problems in the configuration file should be corrected and
149.Nm
150should be run again.
151Attempts to compile a system that had configuration errors
152are likely to fail.
153.Pp
154If the
155.Cd "options INCLUDE_CONFIG_FILE"
156is used in the configuration file the
157entire input file is embedded in the new kernel.
158This means that
159.Xr strings 1
160can be used to extract it from a kernel:
161to extract the configuration information, use the command
162.Pp
163.Dl "strings -n 3 kernel | sed -n 's/^___//p'"
164.Sh DEBUG KERNELS
165Traditional
166.Bx
167kernels are compiled without symbols due to the heavy load on the
168system when compiling a
169.Dq debug
170kernel.
171A debug kernel contains complete symbols for all the source files, and
172enables an experienced kernel programmer to analyse the cause of a problem.
173The
174debuggers available prior to
175.Bx 4.4 Lite
176were able to find some information
177from a normal kernel;
178.Xr gdb 1
179provides very little support for normal kernels, and a debug kernel is needed
180for any meaningful analysis.
181.Pp
182For reasons of history, time and space, building a debug kernel is not the
183default with
184.Fx :
185a debug kernel takes up to 30% longer to build and
186requires about 30 MB of disk storage in the build directory, compared to about 6
187MB for a non-debug kernel.
188A debug kernel is about 11 MB in size, compared to
189about 2 MB for a non-debug kernel.
190This space is used both in the root file
191system and at run time in memory.
192Use the
193.Fl g
194option to build a debug kernel.
195With this option,
196.Nm
197causes two kernel files to be built in the kernel build directory:
198.Bl -bullet
199.It
200.Pa kernel.debug
201is the complete debug kernel.
202.It
203.Pa kernel
204is a copy of the kernel with the debug symbols stripped off.
205This is equivalent
206to the normal non-debug kernel.
207.El
208.Pp
209There is currently little sense in installing and booting from a debug kernel,
210since the only tools available which use the symbols do not run on-line.
211There
212are therefore two options for installing a debug kernel:
213.Bl -bullet
214.It
215.Dq Li "make install"
216installs
217.Pa kernel
218in the root file system.
219.It
220.Dq Li "make install.debug"
221installs
222.Pa kernel.debug
223in the root file system.
224.El
225.Sh FILES
226.Bl -tag -width ".Pa /sys/ Ns Va ARCH Ns Pa /compile/ Ns Ar SYSTEM_NAME" -compact
227.It Pa /sys/conf/files
228list of common files system is built from
229.It Pa /sys/conf/Makefile. Ns Va ARCH
230generic makefile for the
231.Va ARCH
232.It Pa /sys/conf/files. Ns Va ARCH
233list of
234.Va ARCH
235specific files
236.It Pa /sys/ Ns Va ARCH Ns Pa /compile/ Ns Ar SYSTEM_NAME
237default kernel build directory for system
238.Ar SYSTEM_NAME
239on
240.Va ARCH .
241.El
242.Sh SEE ALSO
243.Xr config 5
244.Pp
245The
246.Sx SYNOPSIS
247portion of each device in section 4.
248.Rs
249.%T "Building 4.3 BSD UNIX System with Config"
250.Re
251.Sh BUGS
252The line numbers reported in error messages are usually off by one.
253.Sh HISTORY
254The
255.Nm
256utility appeared in
257.Bx 4.1 .
258