v0.4 - Now with README!

README

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+1) What is it?
+A simple initramfs that looks for a filesystem with a given UUID (not the gpt
+PARTUUID), looks there for a .tar.xz file containing a root filesystem and
+tries to switch root filesystem to a tmpfs where the tarball was extracted.
+
+2) How to use it?
+2.1) Stea^WAcquire statically linked copies of:
+ a) busybox (http://www.busybox.net/)
+ b) pv (http://www.ivarch.com/programs/pv.shtml)
+(protip: use magnets for faster acquiring)
+and put the binaries in the initramfs root directory (hint: ./initramfs)
+
+2.2) Get UUID of your filesystem where you have an xz-compressed tarball of
+your filesystem.
+ ls -l /dev/disk/by-uuid/ might help
+
+2.3) Set these kernel parameters:
+ rootfs_location_uuid - uuid of the filesystem containing rootfs tarball
+ rootfs_filename - tarball filename
+ rootfs_size - size of the tmpfs that will be used as /
+
+2.4) ???
+ (you might want to pray to flying spaghetti monster, or some other imaginary
+ friend of your choice)
+
+2.5) PROFIT!
+ (assuming your system didn't OOM in the process)
+
+3) I've got an idea/suggestion/bugfix!
+ Patches welcome:
+  git format-patch --stdout -M -C -C -1
+

scripts/mkinitramfs

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+#!/bin/sh
+
+die() {
+    echo "${2}"
+    echo "Usage: ${0} <path to directory> <output file>"
+    exit $1
+}
+
+[[ $# -eq 2 ]] || die 22 "Invalid number of arguments"
+[[ -d "${1}" ]] || die 20 "${1} is not a directory"
+[[ -e "${2}" ]] && die 17 "${2} exists"
+
+[[ -f "${1}/pv" ]] || die 2 "${1}/pv does not exist. Read README!"
+[[ -f "${1}/busybox" ]] || die 2 "${1}/busybox does not exist. Read README!"
+
+file=$(readlink -f ${2})
+
+cd "${1}"
+find . -print0 | cpio --null -ov --format=newc | gzip -9 > "${file}"
+