Support for compressed kernel modules

[Luciano Miguel Ferreira Rocha]

On Mon, Nov 27, 2006 at 02:19:41PM +0100, Rory Vieira wrote:
> Hi,
> 
> I'm using BusyBox 1.2.1 (built by buildroot) for my tiny linux env...
> 
> I'm running out of rootfs space, and can save roughly 1Mb if I
> compress the kernel modules.
> Does this version of busybox come with modprobe with gzip support?
> And if so, how do I enable this?

If you apply the attached patch to busybox, and use the attached insmod
script instead of busybox's, you can use compressed modules:

* /lib/modules/<kver>/.../module.ko.gz
 ( find /lib/modules/<kver> -name \*.ko | gzip -9 )
-- or --
* /lib/modules/<kver>/modules.tgz
 ( cd /lib/modules/<kver> && tar cf - `find */ -name \*.ko` | gzip -9 > modules.tgz )
-- or --
* /lib/modules/<kver>/modules.cgz
 ( cd /lib/modules/<kver> && find */ -name \*.ko | cpio -oH newc | gzip -9 > modules.cgz )

-- 
lfr
0/0
-------------- next part --------------
--- busybox-1.2.2.1/libbb/xfuncs.c	2006-07-28 23:53:44.000000000 +0100
+++ busybox-1.2.2.1/libbb/xfuncs.c	2006-11-24 17:09:57.000000000 +0000
@@ -190,14 +190,15 @@
 {
 	static int failed;
 	pid_t pid;
-	void *app = find_applet_by_name(argv[0]);
 
 	// Be nice to nommu machines.
 	failed = 0;
 	pid = vfork();
 	if (pid < 0) return pid;
 	if (!pid) {
-		execvp(app ? CONFIG_BUSYBOX_EXEC_PATH : *argv, argv);
+		execvp(*argv, argv);
+		if (find_applet_by_name(argv[0]))
+			execvp(CONFIG_BUSYBOX_EXEC_PATH, argv);
 
 		// We're sharing a stack with blocked parent, let parent know we failed
 		// and then exit to unblock parent (but don't run atexit() stuff, which
-------------- next part --------------
#!/bin/sh

INSMOD="busybox insmod"
MODULE="$1"

[ -e $MODULE ] && exec $INSMOD $MODULE

umask 077

T=`mktemp -d /tmp/mod.XXXXXX`
[ $? -eq 0  -a -n "$T" ] || exit 1

trap "rm -fr $T" EXIT

cd $T || exit 1

FILE="${MODULE##*/}"
KVER=${MODULE#/lib/modules/}
KMOD=${KVER#*/}
KVER=${KVER%%/*}

KDIR=/lib/modules/$KVER

if [ -e "$MODULE.gz" ]; then
	zcat < $MODULE.gz > $FILE
	$INSMOD $FILE
elif [ -e $KDIR/modules.tgz ]; then
	tar xzf $KDIR/modules.tgz ./$KMOD
	insmod ./$KMOD
elif [ -e $KDIR/modules.cgz ]; then
	zcat < $KDIR/modules.cgz | cpio -id $KMOD > /dev/null
	insmod $KMOD
fi

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