run-init: new applet

function                                             old     new   delta
switch_root_main                                     354     637    +283
drop_usermodehelper                                    -     157    +157
cap_name_to_number                                     -      77     +77
packed_usage                                       31707   31743     +36
applet_names                                        2665    2674      +9
applet_main                                         1544    1548      +4
applet_install_loc                                   193     194      +1
setpriv_main                                         933     928      -5
getcaps                                              131     122      -9
parse_cap                                            117      29     -88
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 5/3 up/down: 567/-102)          Total: 465 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/klibc-utils/run-init.c b/klibc-utils/run-init.c
new file mode 100644
index 000000000..a70d1bfbf
--- /dev/null
+++ b/klibc-utils/run-init.c
@@ -0,0 +1,27 @@
+/*
+ * run-init implementation for busybox
+ *
+ * Copyright (c) 2017 Denys Vlasenko <vda.linux@gmail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+//config:config RUN_INIT
+//config:       bool "run-init"
+//config:       default y
+//config:       select PLATFORM_LINUX
+//config:       help
+//config:       The run-init utility is used from initramfs to select a new
+//config:       root device. Under initramfs, you have to use this instead of
+//config:       pivot_root.
+//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:       run-init 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:       util-linux has a similar tool, switch-root.
+//config:       run-init differs by also having a "-d CAPS_TO_DROP" option.
+
+/* applet and kbuild hooks are in switch_root.c */