xref: /freebsd/usr.sbin/config/config.8 (revision 6af83ee0d2941d18880b6aaa2b4facd1d30c6106)
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28.\"     @(#)config.8	8.2 (Berkeley) 4/19/94
29.\" $FreeBSD$
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31.Dd December 16, 2004
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 Makefile ,
126used by
127.Xr make 1
128in building the system;
129header files,
130definitions of
131the number of various devices that will be compiled into the system.
132.Pp
133After running
134.Nm ,
135it is necessary to run
136.Dq Li make depend
137in the directory where the new makefile
138was created.
139The
140.Nm
141utility prints a reminder of this when it completes.
142.Pp
143If any other error messages are produced by
144.Nm ,
145the problems in the configuration file should be corrected and
146.Nm
147should be run again.
148Attempts to compile a system that had configuration errors
149are likely to fail.
150.Pp
151If the
152.Cd "options INCLUDE_CONFIG_FILE"
153is used in the configuration file the
154entire input file is embedded in the new kernel.
155This means that
156.Xr strings 1
157can be used to extract it from a kernel:
158to extract the configuration information, use the command
159.Pp
160.Dl "strings -n 3 kernel | sed -n 's/^___//p'"
161.Sh DEBUG KERNELS
162Traditional
163.Bx
164kernels are compiled without symbols due to the heavy load on the
165system when compiling a
166.Dq debug
167kernel.
168A debug kernel contains complete symbols for all the source files, and
169enables an experienced kernel programmer to analyse the cause of a problem.
170The
171debuggers available prior to
172.Bx 4.4 Lite
173were able to find some information
174from a normal kernel;
175.Xr gdb 1
176provides very little support for normal kernels, and a debug kernel is needed
177for any meaningful analysis.
178.Pp
179For reasons of history, time and space, building a debug kernel is not the
180default with
181.Fx :
182a debug kernel takes up to 30% longer to build and
183requires about 30 MB of disk storage in the build directory, compared to about 6
184MB for a non-debug kernel.
185A debug kernel is about 11 MB in size, compared to
186about 2 MB for a non-debug kernel.
187This space is used both in the root file
188system and at run time in memory.
189Use the
190.Fl g
191option to build a debug kernel.
192With this option,
193.Nm
194causes two kernel files to be built in the kernel build directory:
195.Bl -bullet
196.It
197.Pa kernel.debug
198is the complete debug kernel.
199.It
200.Pa kernel
201is a copy of the kernel with the debug symbols stripped off.
202This is equivalent
203to the normal non-debug kernel.
204.El
205.Pp
206There is currently little sense in installing and booting from a debug kernel,
207since the only tools available which use the symbols do not run on-line.
208There
209are therefore two options for installing a debug kernel:
210.Bl -bullet
211.It
212.Dq Li "make install"
213installs
214.Pa kernel
215in the root file system.
216.It
217.Dq Li "make install.debug"
218installs
219.Pa kernel.debug
220in the root file system.
221.El
222.Sh FILES
223.Bl -tag -width ".Pa /sys/ Ns Va ARCH Ns Pa /compile/ Ns Ar SYSTEM_NAME" -compact
224.It Pa /sys/conf/files
225list of common files system is built from
226.It Pa /sys/conf/Makefile. Ns Va ARCH
227generic makefile for the
228.Va ARCH
229.It Pa /sys/conf/files. Ns Va ARCH
230list of
231.Va ARCH
232specific files
233.It Pa /sys/ Ns Va ARCH Ns Pa /compile/ Ns Ar SYSTEM_NAME
234default kernel build directory for system
235.Ar SYSTEM_NAME
236on
237.Va ARCH .
238.El
239.Sh SEE ALSO
240.Xr config 5
241.Pp
242The
243.Sx SYNOPSIS
244portion of each device in section 4.
245.Rs
246.%T "Building 4.3 BSD UNIX System with Config"
247.Re
248.Sh HISTORY
249The
250.Nm
251utility appeared in
252.Bx 4.1 .
253.Sh BUGS
254The line numbers reported in error messages are usually off by one.
255