120 lines
2.2 KiB
Bash
Executable file
120 lines
2.2 KiB
Bash
Executable file
#!/bin/sh
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set -eu
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ensure() {
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command -v $1 >/dev/null || (echo "$1 not found"; exit 1)
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}
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ensure curl
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ensure tar
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ensure gunzip
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ensure mount
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uid=$(id -u)
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if [ "$uid" -ne 0 ]; then
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ensure sudo
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exec sudo $0
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fi
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mount -o remount --make-private /
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arch="x86_64"
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case $(uname -m) in
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"x86_64") arch=x86_64 ;;
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"i686") arch=x86 ;;
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*) exit 1 ;;
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esac
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version=${VERSION:-3.15.0}
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branch="v$(echo $version | rev | cut -d'.' -f2- | rev)"
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filename="alpine-minirootfs-$version-$arch.tar.gz"
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# clean up, just in case
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rm -f "$filename"
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umount -R new_root 2>/dev/null || true
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rm -rf new_root
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# download alpine minirootfs
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curl -Ok "https://dl-cdn.alpinelinux.org/alpine/$branch/releases/$arch/$filename"
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# extract the files to new_root
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mkdir new_root
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mount -t tmpfs tmpfs new_root
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< "$filename" gunzip | tar xf - -C new_root
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rm -f "$filename"
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cd new_root
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mkdir old_root
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mount -t sysfs sysfs sys
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mount -t devtmpfs devtmpfs dev
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mount -t proc proc proc
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cp /etc/resolv.conf etc/resolv.conf
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echo '
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pivot_root . old_root || exit 1
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rm second_stage.sh
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apk add alpine-base util-linux-misc syslinux gdb procps
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_ppid=$$
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while [[ "$_ppid" != 1 ]]; do
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parent=$_ppid
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_ppid=$(cut -f4 -d" " /proc/$parent/stat)
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done
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busybox kill -- "-$parent"
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cp /etc/inittab /etc/inittab.bak
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echo "tty1::wait:/sbin/getty -n -l /third_stage.sh 38400 tty1" > /etc/inittab
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# here be dragons
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init_file=/old_root/sbin/init
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init_link=$(readlink $init_file)
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if [[ "$init_link" != "" ]]; then
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init_file=/old_root$init_link
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fi
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echo -e "set follow-fork-mode child
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set solib-absolute-prefix /old_root
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file $init_file
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attach 1
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call (int)execl(\"/sbin/init\", \"/sbin/init\", 0)
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" | gdb
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' > second_stage.sh
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echo '#!/bin/ash
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rm third_stage.sh
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# kill all remaining processes
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cd /proc
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ps ax | awk "{print \$1}" | tail -n +3 | while read pid; do
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if grep -qE "^/dev/\w+ / " /proc/$pid/mounts; then
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kill -9 $pid
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fi
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done
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cd /
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/bin/umount -Rl old_root/* 2>/dev/null
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/bin/umount old_root
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# get nameservers
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udhcpc
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# restore inittab
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mv /etc/inittab.bak /etc/inittab
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# maybe ask user what kernel they want? TODO
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export DISKOPTS="-k lts"
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setup-alpine
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echo "It is now safe to turn off your computer."
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reboot
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' > third_stage.sh
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chmod +x third_stage.sh
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setsid bin/ash second_stage.sh
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