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Diffstat (limited to 'util-linux/switch_root.c')
| -rw-r--r-- | util-linux/switch_root.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c index 7960b67..6034485 100644 --- a/util-linux/switch_root.c +++ b/util-linux/switch_root.c @@ -5,6 +5,29 @@ * * Licensed under GPLv2, see file LICENSE in this source tree. */ +//config:config SWITCH_ROOT +//config: bool "switch_root" +//config: default y +//config: select PLATFORM_LINUX +//config: help +//config: The switch_root utility is used from initramfs to select a new +//config: root device. Under initramfs, you have to use this instead of +//config: pivot_root. (Stop reading here if you don't care why.) +//config: +//config: Booting with initramfs extracts a gzipped cpio archive into rootfs +//config: (which is a variant of ramfs/tmpfs). Because rootfs can't be moved +//config: or unmounted*, pivot_root will not work from initramfs. Instead, +//config: switch_root deletes everything out of rootfs (including itself), +//config: does a mount --move that overmounts rootfs with the new root, and +//config: then execs the specified init program. +//config: +//config: * Because the Linux kernel uses rootfs internally as the starting +//config: and ending point for searching through the kernel's doubly linked +//config: list of active mount points. That's why. + +//applet:IF_SWITCH_ROOT(APPLET(switch_root, BB_DIR_SBIN, BB_SUID_DROP)) + +//kbuild:lib-$(CONFIG_SWITCH_ROOT) += switch_root.o //usage:#define switch_root_trivial_usage //usage: "[-c /dev/console] NEW_ROOT NEW_INIT [ARGS]" |