Re: [PATCH] Re: Building .config into the kernel

Chris Chiappa (griffon@snurgle.org)
Fri, 15 Jan 1999 08:39:28 -0500


On Thu, Jan 14, 1999 at 09:30:56PM -0600, Michael Elizabeth Chastain wrote:
> It discards semantic information from the .config file, and once that
> information is lost, it can't be regenerated.
I'm not sure about this. It's trivial to find the version of a running
kernel and from that you can deduce anything that *isn't* set in .config,
and the space savings are substantial.

> in a standard format (straight gzip compression, no s/CONFIG_// games),
^^^^^^^^^^^
This might be a reasonable thing to do since the way LZ compression is
implemented, killing a redundant string doesn't have that much effect. For
jollies:
-rw-r--r-- 1 griffon root 6960 Jan 15 08:19 config
-rw-r--r-- 1 griffon root 2052 Jan 15 08:19 config.gz
-rw-r--r-- 1 griffon root 1982 Jan 15 08:25 config.hack.gz
-rw-r--r-- 1 griffon root 777 Jan 15 08:22 config.strip.gz
-rw-r--r-- 1 griffon root 731 Jan 15 08:23 config.strip.hack.gz
config is the original file. config.gz is it compresses with gzip -9.
config.hack.gz is it compressed after being run through sed -e s/CONFIG_//.
config.strip.gz is the compresses product after running it through
egrep -v '(^#|^$)', and config.strip.hack.gz is the compressed product after
both the sed and egrep. 46 bytes doesn't seem to me to be all that
important a savings. (This might even get lost in alignment fuzz or
something, I don't know) I would tend to vote for the "egrep" approach
without the "sed" approach.

Other caveats:
o The script makes use of an easily guessable name in /tmp. Unless the
author wants to be flamed on bugtraq, he should probably change it.
o I know the overall tendency is to make files in /proc not human-readable
but it seems like even in 2.2 we're going to have /proc/* still be. A
gzipped file definitely isn't so it should probably be moved deeped into the
hierarchy. /proc/sys/kernel/config.gz maybe? (Unless you want to gunzip on
the fly that is, which is probably not a good idea.)

-- 

+------- --- -- -- - | griffon@snurgle.N0-SPAM.org / My opinions represent snurgle.org : ! Unspoilt by progress / http://www.snurgle.org/~griffon | - -- -- --- -------+

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