#!/bin/sh
# /init — PID 1 entry point for the everything-in-initramfs live image.
#
# The kernel unpacks our cpio.zst into a ramfs, sees no root= parameter,
# and execs /init. Classic initramfs-tools has an elaborate /init that
# mounts a real rootfs and pivot_roots into it; we don't do that —
# there IS no other rootfs, the initramfs IS the rootfs. All we need
# to do is set up the api-vfs mounts systemd expects before PID 1 and
# hand off.
#
# Running systemd directly as PID 1 from kernel /init works (systemd
# detects it's PID 1 and boots normally), but only if /proc, /sys, /dev
# are pre-mounted. Systemd has fallback mount code for these, but it's
# fragile in the ramfs-rootfs case — doing it here explicitly makes
# first-boot failures easier to see and harder to hit.

set -e

echo "vetting-init: bootstrapping api-vfs"

mount -t proc     -o nosuid,noexec,nodev        proc     /proc
mount -t sysfs    -o nosuid,noexec,nodev        sysfs    /sys
mount -t devtmpfs -o mode=0755,nosuid           devtmpfs /dev
mkdir -p /dev/pts /dev/shm /run
mount -t devpts   -o gid=5,mode=620,nosuid,noexec devpts /dev/pts
mount -t tmpfs    -o mode=1777,nosuid,nodev     tmpfs    /dev/shm
mount -t tmpfs    -o mode=0755,nosuid,nodev     tmpfs    /run

echo "vetting-init: handing off to systemd"

exec /lib/systemd/systemd