xref: /freebsd/usr.sbin/config/config.8 (revision 41466b50c1d5bfd1cf6adaae547a579a75d7c04e)
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32.\"     @(#)config.8	8.2 (Berkeley) 4/19/94
33.\" $FreeBSD$
34.\"
35.Dd July 4, 2001
36.Dt CONFIG 8
37.Os
38.Sh NAME
39.Nm config
40.Nd build system configuration files
41.Sh SYNOPSIS
42.Nm
43.Op Fl gp
44.Op Fl d Ar destdir
45.Ar SYSTEM_NAME
46.Sh DESCRIPTION
47This is the old version of the
48.Nm
49program.
50It understands the old autoconfiguration scheme
51used on the HP300, i386, DECstation, and derivative platforms.
52The new version of
53.Nm
54is used with the
55SPARC platform.
56Only the version of
57.Nm
58applicable to the architecture that you are running
59will be installed on your machine.
60.Pp
61.Nm
62builds a set of system configuration files from the file
63.Ar SYSTEM_NAME
64which describes
65the system to configure.
66A second file
67tells
68.Nm
69what files are needed to generate a system and
70can be augmented by configuration specific set of files
71that give alternate files for a specific machine
72(see the
73.Sx FILES
74section below).
75.Pp
76Available options and operands:
77.Bl -tag -width ".Ar SYSTEM_NAME"
78.It Fl d Ar destdir
79Use
80.Ar destdir
81as the output directory, instead of the default one.
82Note that
83.Nm
84does not append
85.Ar SYSTEM_NAME
86to the directory given.
87.It Fl g
88Configure a system for debugging.
89.It Fl p
90Configure a system for profiling; for example,
91.Xr kgmon 8
92and
93.Xr gprof 1 .
94If two or more
95.Fl p
96options are supplied,
97.Nm
98configures a system for high resolution profiling.
99.It Ar SYSTEM_NAME
100Specify the name of the system configuration file
101containing device specifications, configuration options
102and other system parameters for one system configuration.
103.El
104.Pp
105.Nm
106should be run from the
107.Pa conf
108subdirectory of the system source (usually
109.Pa /sys/ Ns Va ARCH Ns Pa /conf ) ,
110where
111.Va ARCH
112represents one of the architectures supported by
113.Fx .
114.Nm
115creates the directory
116.Pa ../compile/ Ns Ar SYSTEM_NAME
117or the one given with the
118.Fl d
119option
120as necessary and places all output files there.
121The output of
122.Nm
123consists of a number of files; for the
124.Tn i386 ,
125they are:
126.Pa ioconf.c ,
127a description
128of what I/O devices are attached to the system;
129.Pa Makefile ,
130used by
131.Xr make 1
132in building the system;
133header files,
134definitions of
135the number of various devices that will be compiled into the system.
136.Pp
137After running
138.Nm ,
139it is necessary to run
140.Dq Li make depend
141in the directory where the new makefile
142was created.
143.Nm
144prints 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 kernel | grep ___"
164.Sh DEBUG KERNELS
165Traditional
166.Bx
167kernels 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
243The
244.Sx SYNOPSIS
245portion of each device in section 4.
246.Rs
247.%T "Building 4.3 BSD UNIX System with Config"
248.Re
249.Sh BUGS
250The line numbers reported in error messages are usually off by one.
251.Sh HISTORY
252The
253.Nm
254command appeared in
255.Bx 4.1 .
256