MirBSD manpage: config(8)

CONFIG(8)                BSD System Manager's Manual                 CONFIG(8)


     config - build kernel compilation directories or modify a kernel


     config [-b builddir] [-p] [-s srcdir] [config-file]
     config -e [-f | -o outfile] [-u] infile


     In the first synopsis form, the config program creates a kernel build
     directory from the kernel configuration file specified by config-file. In
     the second synopsis form, config allows editing of the kernel binary
     specified by infile.

     Furthermore, devices may be enabled, disabled, or modified without recom-
     piling, by editing the kernel executable using the -e option. Similarly,
     you can do the same editing at boot-time, using the in-kernel editor, as
     described in boot_config(8).

     config is most commonly invoked from the directory containing OpenBSD
     kernel configuration files (i.e., /usr/src/sys/arch/i386/conf for i386
     machines). For instance, the following steps would be followed to config-
     ure and compile a new GENERIC kernel (assuming a complete kernel source
     tree is available in /usr/src/sys):

           # cd /usr/src/sys/arch/i386/conf
           # config ./GENERIC
           # cd ../compile/GENERIC
           # make depend && make

     Replace "i386" with the appropriate architecture name.

     For kernel building, the options are as follows:

     -b builddir
             Create the build directory in the path specified by builddir in-
             stead of the default ../compile/SYSTEMNAME.

     -p      Configure for a system that includes profiling code; see kgmon(8)
             and gprof(1). When this option is specified, config acts as if
             the lines "makeoptions PROF="-pg"" and "options GPROF" appeared
             in the specified kernel configuration file. In addition, ".PROF"
             is appended to the default compilation directory name.

             The -p flag is expected to be used for "one-shot" profiles of ex-
             isting systems; for regular profiling, it is probably wiser to
             make a separate configuration containing the makeoptions line.

     -s srcdir
             Use srcdir as the top-level kernel source directory instead of
             the default (four directories above the build directory).

     For kernel modification, the options are as follows:

     -e      Allows the modification of kernel device configuration (see
             boot_config(8)). Temporary changes can be made to the running
             kernel's configuration or a new kernel binary may be written for
             permanent changes between system reboots. See the section Kernel
             modification below for more details.

     -f      Overwrite the infile kernel binary with the modified kernel. Oth-
             erwise, -o should be given to specify an alternate output file.

     -o outfile
             Write the modified kernel to outfile.

     -u      Check to see if the kernel configuration was modified at boot-
             time (i.e., boot -c was used). If so, compare the running kernel
             with the kernel to be edited (infile). If they seem to be the
             same, apply all configuration changes performed at boot.

     The old -g flag is deprecated and no longer supported. Instead, add
     "makeoptions DEBUG="-g"" to the kernel configuration file, along with
     (typically) "options KGDB".

     The output of config consists of a number of files, principally ioconf.c
     (a description of I/O devices that may be attached to the system) and a
     Makefile, used by make(1) when building the kernel.

     After running config it is wise to run "make depend" in the new build
     directory. config prints a reminder of this when it completes.

     If config stops due to errors, the problems reported should be corrected
     and config should be run again. config attempts to avoid changing the
     compilation directory if there are configuration errors, but this code is
     not well-tested and some problems (such as running out of disk space) are

     If config-file is not specified, config uses the current directory as the
     build directory, and looks in it for a file called CONFIG. If you run
     config this way, you must specify the location of the top-level kernel
     source directory using the -s option or by using the "source" directive
     at the beginning of the system configuration file.

     The configuration files consists of various statements which include the

           machine var
                   Required. Specifies the machine architecture.

           include file
                   Include another configuration file.

           option name
                   Set a kernel option. Kernel options may take either the
                   form NAME or the form NAME=value. These options are passed
                   to the compiler with the -D flag.

           rmoption name
                   Delete a previously set option. This is useful when includ-
                   ing another kernel configuration file. A typical use is to
                   include the GENERIC kernel provided with each release and
                   remove options that are unwanted, thus allowing for au-
                   tomatic inclusion of new device drivers.

           maxusers number
                   Required. Used to size various system tables and maximum
                   operating conditions in an approximate fashion. Multiple
                   instances of this keyword may be specified. The number pro-
                   vided in the last instance will be used, and warnings will
                   be printed for each duplicate value. This is convenient
                   when used with the include directive.

           config bsd root on dev [swap on dev [and dev ...]] [dumps on dev
               [and dev ...]]
                   Required. Specifies the swap and dump devices which the
                   system should use.

           config bsd swap generic
                   Otherwise, if generic is specified, the system follows gen-
                   eric routines to decide what should happen.

     Many other statements exist, and the file format is fairly rich; for more
     information see the various configuration files included in the system,
     as well as files.conf(5) for the config rules base.

Kernel modification

     When -e is specified, device parameters that are normally hard-coded into
     the kernel may be changed. This is useful to avoid the need for kernel
     recompilation or rebooting. Modifications are made to the currently run-
     ning kernel and can be written to a new kernel binary so changes are
     preserved during subsequent system restarts.

     When invoked, the kernel identification is first shown.

     # config -e -o bsd.new /bsd
     OpenBSD 2.6-beta (GENERIC.rz0) #0: Mon Oct  4 03:57:22 MEST 1999
     Enter 'help' for information

     One or more warnings may be printed before the ukc> prompt.

           warning: no output file specified

     Neither the -f nor -o option has been specified. Changes will be ignored.

           WARNING this kernel doesn't contain all information needed!
           WARNING the commands add and change might not work.

     The kernel is too old (pre OpenBSD 2.6) and cannot support all of the
     functionality needed by the -e option.

           WARNING kernel mismatch. -u ignored.
           WARNING the running kernel version:

     config does not believe the running kernel is the same as the infile
     specified. Since the log of changes (from boot -c) in the running kernel
     is kernel-specific, the -u option is ignored.

     The commands are as follows:

     add dev                         Add a device through copying another.

     base 8 | 10 | 16                Change the base of numbers displayed and
                                     entered, e.g., I/O addresses in a VAXen
                                     are octal.

     change devno | dev              Modify one or more devices.

     disable attr val | devno | dev  Disable one or more devices.

     enable attr val | devno | dev   Enable one or more devices.

     exit                            Exit without saving changes.

     find devno | dev                Find one or more devices.

     help                            Give a short summary of all commands and
                                     their arguments.

     list                            Show all known devices, a screen at a

     lines [count]                   Set the number of rows per page. 0 dis-
                                     ables paging.

     quit                            Exit and save changes.

     show [attr [val]]               Show all devices for which attribute attr
                                     has the value val.

     timezone [minuteswest [dst]]    Change the tz timezone structure. Without
                                     arguments, displays its current value.

     cachepct [number]               Change the BUFCACHEPERCENT value. Without
                                     arguments, displays its current value.

     nkmempg [number]                Change the NKMEMPAGES value. Without ar-
                                     guments, displays its current value.

     shmseg [number]                 Change the SHMSEG value. Without argu-
                                     ments, displays its current value.

     shmmaxpgs [number]              Change the SHMMAXPGS value. Without argu-
                                     ments, displays its current value.

EXAMPLES (First synopsis)
     A custom kernel is built in the following way.

     To compile your own kernel from a non-writable media (such as a CD-ROM)
     mounted on /usr/src, do the following:

           # cd /somedir
           # cp /usr/src/sys/arch/somearch/conf/SOMEFILE .
           # vi SOMEFILE   (to make any changes)
           # config -s /usr/src/sys -b . SOMEFILE
           # make

     To compile a kernel inside a writable source tree, do the following:

           # cd /usr/src/sys/arch/somearch/conf
           # vi SOMEFILE   (to make any changes)
           # config SOMEFILE
           # cd ../compile/SOMEFILE
           # make

     where somedir is a writable directory, somearch is the architecture
     (e.g., i386), and SOMEFILE should be a name indicative of a particular
     configuration (often that of the hostname). config will warn you if a
     "make clean" is required; you can also do a "make depend" so that you
     will have dependencies there the next time you do a compile.

     After either of these two methods, you can place the new kernel (called
     bsd) in / (i.e., /bsd) and the system will boot it next time. Most people
     save their backup kernels as /bsd.1, /bsd.2, etc.

EXAMPLES (Second synopsis)
     The Ethernet card is not detected at boot because the kernel configura-
     tion does not match the physical hardware configuration, e.g., wrong IRQ
     in OpenBSD/i386. The Ethernet card is supposed to use the ne(4) driver.

     ukc> find ne
     24 ne0 at isa0 port 0x240 size 0 iomem 0xd8000 iosiz 0 irq 9 drq -1 drq2 -1 flags 0x0
     25 ne1 at isa0 port 0x300 size 0 iomem -1 iosiz 0 irq 10 drq -1 drq2 -1 flags 0x0
     26 ne* at isapnp0 port -1 size 0 iomem -1 iosiz 0 irq -1 drq -1 flags 0x0
     27 ne* at pci* dev -1 function -1 flags 0x0
     28 ne* at pcmcia* function -1 irq -1 flags 0x0

     ne1 seems to match the configuration except it uses IRQ 5 instead of IRQ
     10. So the irq on ne1 should be changed via the change command. The dev-
     ice can be specified by either name or number.

     ukc> change ne1
     25 ne1 at isa0 port 0x300 size 0 iomem -1 iosiz 0 irq 10 drq -1 drq2 -1
     change (y/n) ? y
     port [0x300] ?
     size [0] ?
     iomem [-1] ?
     iosiz [0] ?
     irq [10] ? 5
     drq [-1] ?
     drq2 [-1] ?
     flags [0] ?
     25 ne1 changed
     25 ne1 at isa0 port 0x300 size 0 iomem -1 iosiz 0 irq 5 drq -1 drq2 -1 flags 0x0

     Another case is a mistakenly detected non-existing device instead of
     another device at the probed location. One known case is the Mitsumi CD-
     ROM in OpenBSD/i386. The simplest thing to solve that problem is to dis-
     able mcd0.

     ukc> find mcd0
      29 mcd0 at isa0 port 0x300 size 0 iomem -1 iosiz 0 irq 10 drq -1 drq2 -1 flags 0x0
     ukc> disable mcd0
      29 mcd0 disabled
     ukc> find 29
      29 mcd0 at isa0 disable port 0x300 size 0 iomem -1 iosiz 0 irq 10 drq -1 drq2 -1 flags 0x0

     It's also possible to disable all devices with a common attribute. e.g.,

     ukc> disable port 0x300
      25 ne1 disabled
      29 mcd0 already disabled
      72 we1 disabled
      75 el0 disabled
      77 ie1 disabled

     The show command is useful for finding which devices have a certain at-
     tribute. It can also be used to find those devices with a particular
     value for an attribute.

     ukc> show slot
       2 ahc* at eisa0 slot -1
      10 uha* at eisa0 slot -1
      12 ep0 at eisa0 slot -1
      17 ep* at eisa0 slot -1
     102 ahb* at eisa0 slot -1
     103 fea* at eisa0 slot -1
     ukc> show port 0x300
      25 ne1 at isa0 port 0x300 size 0 iomem -1 iosiz 0 irq 10 drq -1 drq2 -1 flags 0x0
      72 we1 at isa0 port 0x300 size 0 iomem 0xcc000 iosiz 0 irq 10 drq -1 drq2 -1 flags 0x0
      75 el0 at isa0 port 0x300 size 0 iomem -1 iosiz 0 irq 9 drq -1 drq2 -1 flags 0x0
      77 ie1 at isa0 port 0x300 size 0 iomem -1 iosiz 0 irq 10 drq -1 drq2 -1 flags 0x0

     It is possible to add new devices, but only devices that were linked into
     the kernel. If a new device is added, following devices will be renum-

     ukc> find ep
      11 ep0 at isa0 port -1 size 0 iomem -1 iosiz 0 irq -1 drq -1 drq2 -1 flags 0x0
      12 ep0 at eisa0 slot -1 flags 0x0
      13 ep0 at pci* dev -1 function -1 flags 0x0
      14 ep* at isapnp0 port -1 size 0 iomem -1 iosiz 0 irq -1 drq -1 flags 0x0
      15 ep* at isa0 port -1 size 0 iomem -1 iosiz 0 irq -1 drq -1 drq2 -1 flags 0x0
      16 ep* at eisa0 slot -1 flags 0x0
      17 ep* at pci* dev -1 function -1 flags 0x0
      18 ep* at pcmcia* dev -1 irq -1 flags 0x0
     ukc> add ep1
     Clone Device (DevNo, 'q' or '?') ? 13
     Insert before Device (DevNo, 'q' or '?') 14
      14 ep1 at pci* dev -1 function -1
     ukc> change 14
      14 ep1 at pci* dev -1 function -1
     change (y/n) ? y
     dev [-1] ? 14
     function [-1] ?
     flags [0] ? 18
      14 ep1 changed
      14 ep1 at pci* dev 14 function -1 flags 0x12

     When done, exit the program with the quit or exit commands. exit will ig-
     nore any changes while quit writes the changes to outfile (if -o or -f
     was given, else ignore changes).

     ukc> quit


     options(4), files.conf(5), boot_config(8)

     The SYNOPSIS portion of each device in section 4 of the manual.

     Building 4.4 BSD Systems with Config.


     The config program appeared in 4.1BSD. It was completely revised in
     4.4BSD. The -e option appeared in OpenBSD 2.6.

MirBSD #10-current             October 15, 1999                              5

Generated on 2021-12-07 11:07:08 by $MirOS: src/scripts/roff2htm,v 1.103 2021/01/23 20:24:35 tg Exp $ — This product includes material provided by mirabilos.

These manual pages and other documentation are copyrighted by their respective writers; their sources are available at the project’s CVSweb, AnonCVS and other mirrors. The rest is Copyright © 2002–2021 MirBSD.

This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report — diffs preferred.