| Denys Vlasenko | 200bcc8 | 2017-08-21 19:30:01 +0200 | [diff] [blame] | 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 |
| Denys Vlasenko | b097a84 | 2018-12-28 03:20:17 +0100 | [diff] [blame] | 9 | //config: bool "run-init (7.7 kb)" |
| Denys Vlasenko | 200bcc8 | 2017-08-21 19:30:01 +0200 | [diff] [blame] | 10 | //config: default y |
| Denys Vlasenko | 200bcc8 | 2017-08-21 19:30:01 +0200 | [diff] [blame] | 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 */ |