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

     config - build kernel compilation directories or modify a kernel

     config [-p] [-b builddir] [-s srcdir] [config-file]
     config [-u] [-f | -o outfile] -e 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.  Devices may be enabled, disabled, or modified
     without recompiling, by editing the kernel executable.  Similarly, the
     same editing can be done at boot-time, using the in-kernel editor, as
     described in boot_config(8).

     For kernel building, the options are as follows:

     -b builddir
	     Create the build directory in the path specified by builddir
	     instead 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 ``option 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
	     existing 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.
	     Otherwise, -o should be given to specify an alternate output

     -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) ``option 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 config is
     run this way, the location of the top-level kernel source directory must
     be specified 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
		   including 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
		   automatic 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
		   provided 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
		   generic 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.

     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
     running 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
	   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

	   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.

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

     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.

     lines [count]		     Set the number of rows per page.

     list			     Show all known devices, a screen at a

     nkmempg [number]		     Change the NKMEMPAGES value.  Without
				     arguments, displays its current value.

     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.
				     minuteswest is the number of minutes west
				     of GMT and dst is non-zero if Daylight
				     Saving Time is in effect.	Without
				     arguments, displays its current value.

EXAMPLES (kernel building)
     Note: The standard OpenBSD kernel configuration (GENERIC or GENERIC.MP)
     is suitable for most purposes.  Use of an alternative kernel
     configuration is not recommended.	A custom kernel is built in the
     following way.

     To compile a 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

     In the examples above, 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
     if a ``make clean'' is required; a ``make depend'' can also be run to
     have dependencies there the next time sources are compiled.

     The new kernel, called bsd, can be copied to /bsd and the system will
     boot it next time.	 Most people save their backup kernels as /bsd.1,
     /bsd.2, etc.

EXAMPLES (kernel modification)
     The Ethernet card is not detected at boot because the kernel
     configuration 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 10 instead of IRQ
     5.	 So the irq on ne1 should be changed via the change command.  The
     device 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
     disable 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.	 For

     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
     attribute.	 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

     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
     ignore any changes while quit writes the changes to outfile (if -o or -f
     was given, else ignore changes).

     ukc> quit

     options(4), boot.conf(5), 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.

     Included files should start with an empty line or comment.

OpenBSD 4.9		       December 10, 2009		   OpenBSD 4.9

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