Inspecting the contents of an initrd file.

Today’s kernels are moving towards initramfs type initrd files. Initramfs is basicly a cpio archive so all we have to do is uncompress it’s contents to a temp folder.

The example below uses the file initrd.SLES10.x64.img from a SLES 10 implementaion.

#create a temp directory

mkdir /tmp/initramfstmp
cd /tmp/initramfstmp

#copy the initrd file to the temp folder

cp initrd.SLES10.x64 /tmp/initramfstmp/initrd.SLES10.x64.img.gz

#uncompress the image file

gunzip -v /tmp/initramfstmp/initrd.SLES10.x64.img.gz

#extract the contents of the cpio archive

cpio -i < /tmp/initramfstmp/initrd.SLES10.x64.img

#list directory

ls -l
View actually out put on next page:

pandora:/tmp # mkdir /tmp/initramfstmp/
pandora:/tmp # cp /media/DELLBOOT/boot/grub/initrd.SLES10.x64 /tmp/initramfstmp/initrd.SLES10.x64.img.gz
pandora:/tmp # cd /tmp/initramfstmp/
pandora:/tmp/initramfstmp # ls
initrd.SLES10.x64.img.gz
pandora:/tmp/initramfstmp # gunzip -v initrd.SLES10.x64.img.gz
initrd.SLES10.x64.img.gz: 64.5% — replaced with initrd.SLES10.x64.img
pandora:/tmp/initramfstmp # cpio -i < initrd.SLES10.x64.img
47264 blocks
pandora:/tmp/initramfstmp # ls -la
total 25044
drwxr-xr-x 17 root root 4096 Jan 29 16:53 .
drwxrwxrwt 50 root root 12288 Jan 29 16:52 ..
drwxr-xr-x 2 root root 4096 Jan 29 16:53 bin
drwxr-xr-x 2 root root 4096 Jan 29 16:53 dev
-rw-r-r- 1 root root 10761 Jan 29 16:53 devz
drwxr-xr-x 2 root root 4096 Jan 29 16:53 download
drwxr-xr-x 8 root root 4096 Jan 29 16:53 etc
-rwxr-xr-x 1 root root 649704 Jan 29 16:53 init
-rwxr-xr-x 1 root root 652544 Jan 29 16:53 init.old
-rwxr-xr-x 1 root root 24199168 Jan 29 16:52 initrd.SLES10.x64.img
-rw-r-r- 1 root root 5604 Jan 29 16:53 installkey.gpg
drwxr-xr-x 5 root root 4096 Jan 29 16:53 lib
drwxr-xr-x 2 root root 4096 Jan 29 16:53 lib64
-rw-r-r- 1 root root 289 Jan 29 16:53 linuxrc.config
drwxr-xr-x 2 root root 4096 Jan 29 16:53 mnt
lrwxrwxrwx 1 root root 45 Jan 29 16:53 modules -> lib/modules/2.6.16.21-override-default/initrd
drwxr-xr-x 2 root root 4096 Jan 29 16:53 mounts
drwxr-xr-x 2 root root 4096 Jan 29 16:53 proc
drwxr-xr-x 2 root root 4096 Jan 29 16:53 root
drwxr-xr-x 2 root root 4096 Jan 29 16:53 sbin
drwxr-xr-x 2 root root 4096 Jan 29 16:53 sys
drwxrwxrwt 2 root root 4096 Jan 29 16:53 tmp
drwxr-xr-x 6 root root 4096 Jan 29 16:53 usr
drwxr-xr-x 11 root root 4096 Jan 29 16:53 var
pandora:/tmp/initramfstmp # pwd
/tmp/initramfstmp