On Sat, Jul 23, 2011 at 01:23:41AM +0200, Tom Gundersen wrote:
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.
v2: copy the needed libraries to the new ramfs
Signed-off-by: Tom Gundersen <teg@jklm.no> --- Makefile | 1 + hooks/shutdown | 16 ++++++++++++++++ install/shutdown | 19 +++++++++++++++++++ shutdown | 10 ++++++++++ 4 files changed, 46 insertions(+), 0 deletions(-) create mode 100644 hooks/shutdown create mode 100644 install/shutdown create mode 100644 shutdown
diff --git a/Makefile b/Makefile index 18df47f..d4bb4e1 100644 --- a/Makefile +++ b/Makefile @@ -35,6 +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/shutdown shutdown
You never added /lib/initcpio/shutdown to the DIRS declare in the Makefile. install(1) doesn't make the directory structure for you here.
install -m755 -t ${DESTDIR}/lib/initcpio init 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..6291a30 --- /dev/null +++ b/hooks/shutdown @@ -0,0 +1,16 @@ +# vim: set ft=sh: +run_hook () +{ + msg -n ":: Creating shutdown ramfs..."
Skip the -n if you aren't going to add a 'done' msg at the end.
+ mkdir -p /run/initramfs/usr/bin + mkdir -p /run/initramfs/usr/sbin + mkdir -p /run/initramfs/bin + mkdir -p /run/initramfs/sbin + mkdir -p /run/initramfs/lib
Such repetition... -p is only necessary on the first call.
+ cp /bin/busybox /run/initramfs/bin/ + cp /lib/ld-linux-x86-64.so.2 /run/initramfs/lib/
You can't hardcode this -- it totally precludes 32 bit. Since we're running this from the initramfs anyways, I suggest we just copy over /lib/ld-* to /run/initramfs/bin.
+ cp /lib/libc.so.6 /run/initramfs/lib/
Same here. cp /lib/libc.* /run/initramfs/lib/
+ + chroot /run/initramfs /bin/busybox --install + cp /shutdown /run/initramfs/ +} diff --git a/install/shutdown b/install/shutdown new file mode 100644 index 0000000..9f8076b --- /dev/null +++ b/install/shutdown @@ -0,0 +1,19 @@ +# vim:set ft=sh: + +build() +{ + MODULES="" + BINARIES="" + FILES="" + SCRIPT="shutdown" + add_binary /lib/initcpio/shutdown /shutdown +} + +help () +{ +cat <<HELPEOF + This hook will create a shutdown initrd in /run/mkinitramfs + that we can pivot to on shutdown in order to unmount / + (and any submounts such as /usr) cleanly. +HELPEOF +}
This is all bash, and I spent a fair bit of time cleaning things up in the install directory. Can I pedantic and ask for the same style? #!/bin/bash build() { foo bar } help() { cat <<HELPEOF i halp you. EOF } # vim: set ft=sh ts=4 sw=4 et: If a var isn't defined, just leave it out. It's all unset prior to the hook being run anyways.
diff --git a/shutdown b/shutdown new file mode 100644
Doesn't this need to be executable? Or are we sourcing this?
index 0000000..a55975f --- /dev/null +++ b/shutdown @@ -0,0 +1,10 @@ +#!/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 +[ "$1" = "reboot" ] && reboot -f +[ "$1" = "poweroff" ] && poweroff -f +[ "$1" = "halt" ] && halt -f
Would probably make sense to throw this into a case statement: case "$1" in reboot|poweroff|halt) "$1" -f ;; *) defaultaction ;; esac Not sure what that default action should be, but I suggest we do _something_. d