Enabling the shutdown hook and using systemd v31
(which is yet to be released), means that on shutdown the root
will be pivoted to /run/initramfs, from where the rootfs and
all its submonuts (such as /usr) are unmounted cleanly.
The same functionality will be supported in a future release of
initscript.
A natural next step is to add an "/usr"-hook, which mounts the /usr
partition (if it exists) in the initramfs, so initscripts (and systemd)
can always rely on it being mounted, and we no longer need to move some
binaries/libraries to /bin, /sbin and /lib (as this does not work well
at the moment).
One might argue that this functionality does not beling in mkinitrd.
The reason I propose it for inclusion here is:
- it is independent of initscripts, so does not really belong there either.
- in the future one might imagine extending this to integrate more tightly
with the rest of the initramfs (e.g. store state/logs in /run/initramfs
to ease debugging, or add shutdown-hooks, to go with the boot-hooks, to
gracefully tear down things such as dm or nfs mounts at shutdown).
- by behaving like dracut, integrating with systemd became trivial, and IMHO
there is no point in systemd/initscripts/dracut/mkinitrd differing at the
interface level.
Signed-off-by: Tom Gundersen <teg(a)jklm.no>
---
v2: copy the needed libraries to the new ramfs
v3: support for 32-bit, and cleanup
v4: fix Makefile++
v5: include all the needed libraries (typo)
Makefile | 2 +-
hooks/shutdown | 17 +++++++++++++++++
install/shutdown | 16 ++++++++++++++++
shutdown | 12 ++++++++++++
4 files changed, 46 insertions(+), 1 deletions(-)
create mode 100644 hooks/shutdown
create mode 100644 install/shutdown
create mode 100644 shutdown
diff --git a/Makefile b/Makefile
index 18df47f..56783bb 100644
--- a/Makefile
+++ b/Makefile
@@ -35,7 +35,7 @@ install: all
chmod 755 ${DESTDIR}/bin/lsinitcpio ${DESTDIR}/sbin/mkinitcpio
install -m644 mkinitcpio.conf ${DESTDIR}/etc/mkinitcpio.conf
- install -m755 -t ${DESTDIR}/lib/initcpio init
+ install -m755 -t ${DESTDIR}/lib/initcpio init shutdown
install -m644 -t ${DESTDIR}/lib/initcpio init_functions functions
install -m644 01-memdisk.rules ${DESTDIR}/lib/initcpio/udev/01-memdisk.rules
diff --git a/hooks/shutdown b/hooks/shutdown
new file mode 100644
index 0000000..505d2d6
--- /dev/null
+++ b/hooks/shutdown
@@ -0,0 +1,17 @@
+# vim: set ft=sh:
+run_hook ()
+{
+ msg -n ":: Creating shutdown ramfs..."
+ mkdir -p /run/initramfs/usr/bin
+ mkdir /run/initramfs/usr/sbin
+ mkdir /run/initramfs/bin
+ mkdir /run/initramfs/sbin
+ mkdir /run/initramfs/lib
+ cp /bin/busybox /run/initramfs/bin/
+ cp -P /lib/ld-* /run/initramfs/lib/
+ cp -P /lib/libc* /run/initramfs/lib/
+
+ chroot /run/initramfs /bin/busybox --install
+ cp /shutdown /run/initramfs/
+ msg "done."
+}
diff --git a/install/shutdown b/install/shutdown
new file mode 100644
index 0000000..3e37326
--- /dev/null
+++ b/install/shutdown
@@ -0,0 +1,16 @@
+#!/bin/bash
+
+build() {
+ SCRIPT="shutdown"
+ add_binary /lib/initcpio/shutdown /shutdown
+}
+
+help () {
+ cat <<HELPEOF
+This hook will create a shutdown initrd in /run/initramfs
+that we can pivot to on shutdown in order to unmount /
+(and any submounts such as /usr) cleanly.
+HELPEOF
+}
+
+# vim: set ft=sh ts=4 sw=4 et:
diff --git a/shutdown b/shutdown
new file mode 100644
index 0000000..db2d394
--- /dev/null
+++ b/shutdown
@@ -0,0 +1,12 @@
+#!/bin/sh
+# shutdown
+
+# unmount everything that was mounted on the old root
+umount `mount | awk '{ print $3 }' | grep "^/oldroot" | sort -r`
+
+# reboot / poweroff / halt, depending on the argument passed by init
+# if something invalid is passed, we halt
+case "$1" in
+ reboot|poweroff|halt) "$1" -f ;;
+ *) halt -f;;
+esac
--
1.7.6