1/* 2 * run-init implementation for busybox 3 * 4 * Copyright (c) 2017 Denys Vlasenko <vda.linux@gmail.com> 5 * 6 * Licensed under GPLv2, see file LICENSE in this source tree. 7 */ 8//config:config RUN_INIT 9//config: bool "run-init (7.7 kb)" 10//config: default y 11//config: help 12//config: The run-init utility is used from initramfs to select a new 13//config: root device. Under initramfs, you have to use this instead of 14//config: pivot_root. 15//config: 16//config: Booting with initramfs extracts a gzipped cpio archive into rootfs 17//config: (which is a variant of ramfs/tmpfs). Because rootfs can't be moved 18//config: or unmounted, pivot_root will not work from initramfs. Instead, 19//config: run-init deletes everything out of rootfs (including itself), 20//config: does a mount --move that overmounts rootfs with the new root, and 21//config: then execs the specified init program. 22//config: 23//config: util-linux has a similar tool, switch-root. 24//config: run-init differs by also having a "-d CAPS_TO_DROP" option. 25 26/* applet and kbuild hooks are in switch_root.c */ 27