On Fri, Jul 22, 2011 at 7:13 PM, Tom Gundersen <teg@jklm.no> 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 v3: support for 32-bit, and cleanup If you put these below the --- (three dashes), they won't show up when you commit to git. (Use git format-patch then edit the results before send-email).

Signed-off-by: Tom Gundersen <teg@jklm.no> ---  Makefile         |    1 +  hooks/shutdown   |   17 +++++++++++++++++  install/shutdown |   16 ++++++++++++++++  shutdown         |   12 ++++++++++++  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        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..f22a0f0 --- /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

One liner: mkdir -p /run/initramfs/{usr/bin,usr/sbin,bin,sbin,lib}

+    cp /bin/busybox /run/initramfs/bin/ +    cp /lib/ld-* /run/initramfs/lib/ +    cp /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..019a6a5 --- /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/mkinitramfs +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

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@jklm.no> --- v2: copy the needed libraries to the new ramfs v3: support for 32-bit, and cleanup v4: fix Makefile++ 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..5241a85 --- /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