From f77041a12a5484769ef982c324e2230ab9c2e377 Mon Sep 17 00:00:00 2001
From: James Le Cuirot <chewi@gentoo.org>
Date: Wed, 22 Feb 2017 13:29:20 +0000
Subject: [PATCH 1/3] Ignore a fakeinit binary

---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..489fda8
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/fakeinit

From b69d42fb27472f39b5a01104827b4072dd7cfbc6 Mon Sep 17 00:00:00 2001
From: James Le Cuirot <chewi@gentoo.org>
Date: Wed, 22 Feb 2017 13:46:28 +0000
Subject: [PATCH 2/3] Bind mount just the init file

This is cleaner and saves you from having to copy telinit beforehand.
---
 takeover.sh | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/takeover.sh b/takeover.sh
index 7c04fb2..fa887d4 100755
--- a/takeover.sh
+++ b/takeover.sh
@@ -2,7 +2,6 @@
 set -e
 
 TO=/takeover
-OLD_TELINIT=/sbin/telinit
 PORT=80
 
 cd "$TO"
@@ -47,7 +46,6 @@ if [ "$a" != "OK" ] ; then
 fi
 
 ./busybox echo "Preparing init..."
-./busybox cp $OLD_TELINIT tmp/telinit
 ./busybox cat >tmp/init <<EOF
 #!${TO}/busybox sh
 
@@ -80,9 +78,9 @@ fi
 ./busybox echo "You may then kill the remnants of this session and any remaining"
 ./busybox echo "processes from your new SSH session, and umount the old root filesystem."
 
-./busybox mount --bind tmp /sbin
+./busybox mount --bind tmp/init /sbin/init
 
-./tmp/telinit u
+telinit u
 
 ./busybox sleep 10
 

From 5cd2f683aa41513acefcdb4920aaff0ce6305296 Mon Sep 17 00:00:00 2001
From: James Le Cuirot <chewi@gentoo.org>
Date: Wed, 22 Feb 2017 13:49:27 +0000
Subject: [PATCH 3/3] Support systemd and potentially other inits with a
 telinit wrapper

---
 README.md   | 7 ++++---
 takeover.sh | 8 +++++---
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index a7e7eec..50d6b5a 100644
--- a/README.md
+++ b/README.md
@@ -28,9 +28,10 @@ handholding, this script is not for you.
 
 ## Compatibility
 
-This script is designed for systems using sysvinit that support the `telinit u`
-command to reload `/sbin/init`. If your system uses something else, you will
-have to adapt it, or this might not work at all. You're on your own here.
+This script is designed for init systems that support the `telinit u` command to
+reload the init binary. This includes sysvinit and systemd. If your init system
+works a different way, you will have to adapt it, or this might not work at
+all. You're on your own here.
 
 You should always test this in a VM first. You can grab a tarball of your live
 root filesystem, extract it into a VM image, get your VM up and running (boot
diff --git a/takeover.sh b/takeover.sh
index fa887d4..784b142 100755
--- a/takeover.sh
+++ b/takeover.sh
@@ -2,6 +2,7 @@
 set -e
 
 TO=/takeover
+OLD_INIT=$(readlink /proc/1/exe)
 PORT=80
 
 cd "$TO"
@@ -46,7 +47,7 @@ if [ "$a" != "OK" ] ; then
 fi
 
 ./busybox echo "Preparing init..."
-./busybox cat >tmp/init <<EOF
+./busybox cat >tmp/${OLD_INIT##*/} <<EOF
 #!${TO}/busybox sh
 
 exec <"${TO}/${TTY}" >"${TO}/${TTY}" 2>"${TO}/${TTY}"
@@ -54,11 +55,12 @@ cd "${TO}"
 
 ./busybox echo "Init takeover successful"
 ./busybox echo "Pivoting root..."
+./busybox mount --make-rprivate /
 ./busybox pivot_root . old_root
 ./busybox echo "Chrooting and running init..."
 exec ./busybox chroot . /fakeinit
 EOF
-./busybox chmod +x tmp/init
+./busybox chmod +x tmp/${OLD_INIT##*/}
 
 ./busybox echo "Starting secondary sshd"
 
@@ -78,7 +80,7 @@ fi
 ./busybox echo "You may then kill the remnants of this session and any remaining"
 ./busybox echo "processes from your new SSH session, and umount the old root filesystem."
 
-./busybox mount --bind tmp/init /sbin/init
+./busybox mount --bind tmp/${OLD_INIT##*/} ${OLD_INIT}
 
 telinit u