>b) Store a copy of the kernel's config file in the kernel itself,
>   in a manner that's easily extractable by a user.
>
>   My initial experiments were to add something like the following to
>   vers.c (with `"' and `\' appropriately \-quoted):
>
>	#ifdef STORE_CONFIG
>	const char kernel_config[] = "
>	#       $NetBSD: GENERIC,v 1.381 2000/11/28 19:44:07 augustss Exp $
>	#
>	#       GENERIC -- everything that's currently supported
>	#
>	   [...]
>	# mouse & keyboard multiplexor pseudo-devices
>	pseudo-device   wsmux           2
>	";
>	#endif /* STORE_CONFIG */
>
>   That way you'd only get the config file compiled in if you asked for it,
>   which possibly could be the default. It's ~ 25K extra on a 3000K i386
>   GENERIC kernel.
>
>   I'm not 100% sure of the easiest way to extract this info though;
>   using gdb and 'print kernel_config' displays the LFs as the literal
>   \n.

freebsd has done this for as long as i can remember...not that i
remember *that* far back.  :)

their method is like this:

 * add 'options INCLUDE_CONFIG_FILE' to your kernel config
 * config makes two files for this: config.c and opt_config.h
 * opt_config.h #defines INCLUDE_CONFIG_FILE
 * config.c looks like this:

    #include "opt_config.h"
    #ifdef INCLUDE_CONFIG_FILE
    static const char config[] = "\
    START CONFIG FILE <config name>\n\
    ___#\n\
    ...(thus continues the config file, with each line indented with ___)
    ___\n\
    END CONFIG FILE <config name>\n\
    ";
    #endif /* INCLUDE_CONFIG_FILE */

the symbol is a static, so you can't "print" it (easily) via gdb or
ddb, but you can easily do this:

    # strings /kernel | sed -n s/^___//p > configfile

to extract a copy.  a sysctl to extract it should also be easy.

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