doesn't properly unpack initrd/initramfs (which is a cpio archive) on debian

[dilinger]

I could've sworn that this used to work, but my tests on current debian stable have it not working.

On debian 13 (dtrx 8.5.3-3), if I run lsinitramfs on the latest generated initrd, I get a list of almost 2000 files and directories inside of the cpio archive:

dilinger@hm90:/tmp$ file /boot/initrd.img-6.12.41+deb13-amd64 
/boot/initrd.img-6.12.41+deb13-amd64: ASCII cpio archive (SVR4 with no CRC)
dilinger@hm90:/tmp$ lsinitramfs /boot/initrd.img-6.12.41+deb13-amd64 |wc -l
1839

However, if I then attempt to use dtrx to unpack that initrd, it only unpacks a single file. This is obviously incorrect behavior.

dilinger@hm90:/tmp$ dtrx /boot/initrd.img-6.12.41+deb13-amd64 
/boot/initrd.img-6.12.41+deb13-amd64 contains one directory but its name doesn't match.
 Expected: initrd.img-6.12.41+deb13-amd64
   Actual: kernel/
You can:
 * extract the directory _I_nside a new directory named initrd.img-6.12.41+deb13-amd64
 * extract the directory and _R_ename it initrd.img-6.12.41+deb13-amd64
 * extract the directory _H_ere
What do you want to do?  (I/r/h) 
dilinger@hm90:/tmp$ find initrd.img-6.12.41+deb13-amd64/
initrd.img-6.12.41+deb13-amd64/
initrd.img-6.12.41+deb13-amd64/kernel
initrd.img-6.12.41+deb13-amd64/kernel/x86
initrd.img-6.12.41+deb13-amd64/kernel/x86/microcode
initrd.img-6.12.41+deb13-amd64/kernel/x86/microcode/AuthenticAMD.bin
dilinger@hm90:/tmp$ 

[noahp]

🤔 interesting- it looks like initramfs archives are actually multiple cpio archives concatenated together, there's some special logic here to handle it:
https://salsa.debian.org/kernel-team/initramfs-tools/-/blob/v0.150/unmkinitramfs.c?ref_type=tags

i think the simplest approach for dtrx would be to add detection for initramfs archives, and use the unmkramrfs utility instead of cpio