mkinitramfs.sh

#!/bin/bash
set -e
mkdir -vp initramfs/{bin,etc,dev,sys,proc,root,tmp,usr,var,mnt,home}
mkdir -vp initramfs/etc/init.d
test -L initramfs/sbin || ln -vfs bin initramfs/sbin
test -f initramfs/bin/busybox || wget -O initramfs/bin/busybox https://busybox.net/downloads/binaries/1.21.1/busybox-x86_64
chmod +x initramfs/bin/busybox
for symlink in \[ \[\[ adjtimex arp arping ash awk base64 basename beep blkid blockdev bootchartd bunzip2 bzcat bzip2 brctl cal cat catv chat chattr chgrp chmod chown chpasswd chpst chrt chvt cksum clear cmp comm conspy cp cpio crond crontab cryptpw cttyhack cut date dc dd deallocvt depmod devmem df dhcprelay diff dirname dmesg dnsd dnsdomainname dos2unix du dumpkmap dumpleases echo ed egrep eject env envdir envuidgid ether-wake expand expr fakeidentd false fbset fbsplash fdflush fdformat fdisk fgconsole fgrep find findfs flock fold free freeramdisk fsck fsck.minix fsync ftpget ftpput fuser getopt grep groups gunzip gzip hd hdparm head hexdump hostid hostname hush hwclock id  install ionice iostat ipaddr ipcalc ipcrm ipcs kbd_mode kill killall killall5 klogd last less linux32 linux64 ln loadfont loadkmap logger logname logread losetup lpd lpq lpr ls lsattr lsmod lsof lspci lsusb lzcat lzma lzop lzopcat makedevs makemime man md5sum mdev mesg microcom mkdir mkdosfs mke2fs mkfifo mkfs.ext2 mkfs.minix mkfs.vfat mknod mkpasswd mkswap modprobe mktemp modinfo more mount mountpoint mpstat mt mv nameif nanddump nandwrite nbd-client nc netstat nice nmeter nohup nslookup od openvt passwd patch pgrep pidof ping ping6 pipe_progress pkill pmap popmaildir printenv printf ps pscan pstree pwd pwdx raidautorun rdate rdev readahead readlink readprofile realpath reformime remove-shell renice reset resize rev rm rmdir rmmod route rpm rpm2cpio rtcwake run-parts runlevel runsv runsvdir rx script scriptreplay sed sendmail seq setarch setconsole setfont setkeycodes setlogcons setserial setsid setuidgid sh sha1sum sha256sum sha3sum sha512sum showkey slattach sleep smemcap softlimit sort split start-stop-daemon stat strings stty sum sv svlogd sysctl syslogd tac tail tar tcpsvd tee telnet test tftp time timeout top touch tr traceroute traceroute6 true tty ttysize tunctl udhcpc udhcpd udpsvd umount uname unexpand uniq unix2dos unlzma unlzop unxz unzip uptime users usleep uudecode uuencode vconfig vi vlock volname wall watch watchdog wc wget which who whoami whois xargs xz xzcat yes zcat zcip acpid add-shell addgroup adduser delgroup deluser chroot ftpd getty halt httpd init ifconfig ifdown ifenslave ifplugd ifup inetd insmod ip iplink iproute iprule iptunnel ntpd pivot_root poweroff powertop reboot su sulogin swapoff swapon switch_root sync telnetd tftpd login;do
    test -L initramfs/bin/$symlink || ln -vfs busybox initramfs/bin/$symlink
done
test -L initramfs/linuxrc || ln -vfs bin/busybox initramfs/linuxrc
test -L initramfs/init || ln -vfs sbin/busybox initramfs/init
cat << __EOF__ > initramfs/etc/inittab
::sysinit:/etc/init.d/rcS
tty1::respawn:/sbin/getty -nl /sbin/autologin 38400 tty1
::restart:/sbin/init
::ctrlaltdel:/sbin/reboot
::shutdown:/sbin/poweroff
__EOF__
cat << __EOF__ > initramfs/etc/init.d/rcS
#!/bin/sh
mount -t proc proc /proc
mount -t sysfs sysfs /sys
mount -t devtmpfs dev /dev
mount -o remount,rw /
mkdir -p /dev/pts
mkdir -p /dev/shm
mount -a
__EOF__
chmod +x initramfs/etc/init.d/rcS
cat << __EOF__ > initramfs/etc/fstab
proc            /proc        proc     defaults          0       0
sysfs           /sys         sysfs    defaults          0       0
dev             /dev         devtmpfs defaults          0       0
devpts          /dev/pts     devpts   defaults          0       0
tmpfs           /dev/shm     tmpfs    defaults          0       0
tmpfs           /tmp         tmpfs    defaults          0       0
__EOF__
cat << __EOF__ > initramfs/sbin/autologin-
#!/bin/sh
busybox login -f root
__EOF__
chmod +x initramfs/sbin/autologin
cat << __EOF__ > initramfs/etc/passwd
root:x:0:0:root:/root:/bin/sh
__EOF__
fakeroot=fakeroot
if [[ "$FAKEROOTKEY" != "" ]] || [[ "$UID" == "0" ]];then
    fakeroot=
fi
cd initramfs
find . -print0 | $fakeroot cpio --null -ov --format=newc | gzip -9 > ../initramfs.gz
cd ..
echo "-------------------------"
echo "Fertig."
echo "-------------------------"