Added mkinitcpio-growrootfs package

PKGBUILD

@@ -0,0 +1,28 @@
+# Maintainer: Greg Sutcliffe <greg.sutcliffe at gmail dot com>
+# Mostly inspired from Debian's cloud-initramfs-growroot
+
+pkgname=mkinitcpio-growrootfs
+pkgver=0.1
+pkgrel=4
+pkgdesc="mkinitcpio hook to autoscale the rootfs to the size of the partition"
+url="https://github.com/aryklein/mkinitcpio-growrootfs"
+arch=('any')
+license=('GPL3')
+depends=('util-linux' 'e2fsprogs')
+install=${pkgname}.install
+source=('growpart'
+        'growfs-hook'
+        'growfs-install')
+sha256sums=('13428ca6e335176d5ebfd30027f3a4dbc9b8054e6d49f631f87aae55d9ffcb8c'
+            '69dcb1143dd84d1f7a834bac58e7fb03c28f63cf588a25bb1c444fb1ebef828e'
+            '656083022534ea34e10926bd63a7efad5a56dbaa5fcb569c2df0201b57a4cd39')
+package() {
+    install -m755 -d "${pkgdir}/usr/bin"
+    install -m755 "${srcdir}/growpart" "${pkgdir}/usr/bin/growpart"
+
+    install -m755 -d "${pkgdir}/usr/lib/initcpio/install"
+    install -m644 "${srcdir}/growfs-install" "${pkgdir}/usr/lib/initcpio/install/growfs"
+
+    install -m755 -d "${pkgdir}/usr/lib/initcpio/hooks"
+    install -m644 "${srcdir}/growfs-hook" "${pkgdir}/usr/lib/initcpio/hooks/growfs"
+}

growfs-hook

@@ -0,0 +1,79 @@
+#!/bin/sh
+
+run_hook() {
+  echo "GrowRootFS: starting"
+
+  # if a file indicates we should do nothing, then just exit
+  for f in /var/lib/cloud/instance/root-grown /etc/growroot-disabled \
+      /etc/growroot-grown; do
+    [ -f "${rootmnt}$f" ] && echo "GrowRootFS: disabled by file" && return 0
+  done
+
+  # figure out what disk '$root' is on
+  { [ ! -L "${root}" ] && rootdev=${root} || rootdev=$(readlink -f "${root}") ; } || { echo "failed to get target of link for ${root}" && 
+return 0 ; }
+
+  case "${rootdev}" in
+    *[0-9]) : ;;
+    # the root is a disk, not a partition (does not end in a digit)
+    # no need to do anything in this case, kernel already knows the full size.
+    *) echo "GrowRootFS: ${rootdev} is a disk, not a partition, no action" && return 0 ;;
+  esac
+
+  # remove all consective numbers from the end of rootdev to get 'rootdisk'
+  rootdisk=${rootdev}
+  while [ "${rootdisk%[0-9]}" != "${rootdisk}" ]; do
+    rootdisk=${rootdisk%[0-9]};
+  done
+  partnum=${rootdev#${rootdisk}}
+
+  # if the basename of the root device (ie 'xvda1' or 'sda1') exists
+  # in /sys/block/ then it is a block device, not a partition
+  # (xen xvda1 is an example of such a funny named block device)
+  [ -e "/sys/block/${rootdev##*/}" ] && echo "GrowRootFS: ${rootdev} is a block device" && return 0
+
+  # if growpart fails, exit.
+  # we capture stderr because on success of dry-run, it writes
+  # to stderr what it would do.
+  out=$(growpart --dry-run "${rootdisk}" "${partnum}" 2>&1) || { echo "GrowRootFS: ${out}" && return 1; }
+
+  # if growpart would change something, --dry-run will write something like
+  #  CHANGE: partition=1 start=2048 old: size=1024000 end=1026048 new: size=2089192,end=2091240
+  # anything else, exit
+  case "${out}" in
+    CHANGE:*) :;;
+    *) echo "GrowRootFS: ${out}" && return 0;;
+  esac
+
+  ## Wait for any of the initial udev events to finish
+  ## This is to avoid any other processes using the block device that the
+  ## root partition is on, which would cause the sfdisk 'BLKRRPART' to fail.
+  udevadm settle --timeout ${rootdelay:-30} || { echo "GrowRootFS: WARNING: udevadm settle prior to growpart failed" && return 1 ; }
+
+  if out=$(growpart "${rootdisk}" "${partnum}" 2>&1); then
+    case "$out" in
+      CHANGED:*) echo "GrowRootFS: $out";;
+      NOCHANGE:*)
+        echo "GrowRootFS: WARNING: expected to grow partition, but did not";;
+      *) echo "GrowRootFS: unexpected output: ${out}"
+    esac
+  else
+    echo "GrowRootFS: WARNING: resize failed: $out"
+  fi
+
+  ## Wait for the partition re-read events to complete
+  ## so that the root partition is available when we try and mount it.
+  udevadm settle --timeout ${rootdelay:-30}
+
+  # Need to figure out the rootfs type somehow
+  # For now we only support ext2/3/4
+  fsck -f ${rootdev}
+  resize2fs -p ${rootdev}
+
+  ## write to /etc/grownroot-grown. most likely this wont work (readonly)
+  { date --utc > "${rootmnt}/etc/growroot-grown" ; } >/dev/null 2>&1 || :
+
+  echo "GrowRootFS: done"
+  sleep 1
+
+}

growfs-install

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+build() {
+    add_binary date
+    add_binary growpart
+    add_binary resize2fs
+    add_binary sfdisk
+    add_runscript
+}
+
+help() {
+    cat <<HELPEOF
+This hook expands the root filesystem to the size of the partition
+which is mostly useful for cloud images to expand to the block device
+they've been given.
+HELPEOF
+}
+
+# vim: set ft=sh ts=4 sw=4 et: