First cut of swap image and example

Signed-off-by: Avi Deitcher <avi@deitcher.net>

Fix spaces after commas

Remove MAINTAINER

Signed-off-by: Avi Deitcher <avi@deitcher.net>

Simplify swap.yml example to remove files section

Signed-off-by: Avi Deitcher <avi@deitcher.net>

Switch swap.sh to sh from bash and remove bash from image

Signed-off-by: Avi Deitcher <avi@deitcher.net>

Replace fallocate with dd and update calculation function to support it

Signed-off-by: Avi Deitcher <avi@deitcher.net>

Fix indentation

Signed-off-by: Avi Deitcher <avi@deitcher.net>

Change link to swap to just swap.sh

Signed-off-by: Avi Deitcher <avi@deitcher.net>

Fix indent

Signed-off-by: Avi Deitcher <avi@deitcher.net>

pkg/swap/swap.sh

@@ -0,0 +1,135 @@
+#!/bin/sh
+
+set -e
+
+while [ $# -gt 1 ]; do
+	key="$1"
+
+	case $key in
+		--debug)
+			set -x
+			;;
+		--path)
+			path="$2"
+			shift # past argument
+			;;
+		--size)
+			size="$2"
+			shift # past argument
+			;;
+		--encrypt)
+			ENCRYPT=true
+			;;
+		--condition)
+			CONDITIONS="$CONDITIONS $2"
+			shift
+			;;
+		*)
+			echo "Unknown option passed to swapmaker: $key"      # unknown option
+			exit 1
+			;;
+	esac
+	shift # past argument or value
+done
+
+function disksize_to_count {
+	local blocksize=$1
+	local origsize=$2
+	local ret
+	case $origsize in
+		*G)
+			ret=$(( ${origsize%%G} * 1024 * 1024 * 1024 ))
+			;;
+		*M)
+			ret=$(( ${origsize%%M} * 1024 * 1024 ))
+			;;
+		*K)
+			ret=$(( ${origsize%%K} * 1024 ))
+			;;
+		*)
+			ret=$origsize
+			;;
+	esac
+	ret=$(( $ret / $blocksize ))
+	echo $ret
+}
+
+
+## make sure path is valid
+if [ -z "${path}" ]; then
+	echo "swap: --file <path> must be defined"
+	exit 1
+fi
+if [ "${path:0:5}" != "/var/" -o ${#path} -lt 6 ]; then
+	echo "--file <path> option must be under /var"
+	exit 1
+fi
+if [ -z "${size}" ]; then
+	echo "swap: --size <size> must be defined"
+	exit 1
+fi
+
+
+
+## check each of our conditions
+for cond in $CONDITIONS; do
+	# split the condition parts
+	IFS=: read condtype arg1 arg2 arg3 arg4 <<< "$cond"
+	case $condtype in
+		part)
+			partition=$arg1
+			required=$arg2
+			# check that the path exists as its own mount point
+			set +e
+			grep -qs $partition /proc/mounts
+			is_mnt=$?
+			set -e
+			if [ $is_mnt -ne 0 ]; then
+				[ "$required" == "true" ] && exit 1
+				exit 0
+			fi
+			;;
+		partsize)
+			partition=$arg1
+			minsize=$arg2
+			required=$arg3
+			# check that the partition on which it exists has sufficient size
+			partsize=$(df -k $partition | tail -1 | awk '{print $2}')
+			partsize=$(( $partsize * 1024 ))
+			# convert minsize to bytes
+			minsize=$(disksize_to_count 1 $minsize)
+			if [ $partsize -lt $minsize ]; then
+				[ "$required" == "true" ] && exit 1
+				exit 0
+			fi
+			;;
+		*)
+			echo "Unknown condition: $cond"
+			exit 1
+			;;
+	esac
+done
+## if a condition failed:
+### Required? exit 1
+### Else? exit 0
+
+
+## Allocate the file
+dd if=/dev/zero of=$path bs=1024 count=$(disksize_to_count 1024 $size)
+chmod 0600 $path
+
+## was it encrypted? use cryptsetup and get the mapped device
+if [ "$ENCRYPT" == "true" ]; then
+	# might need
+	#loop=$(losetup -f)
+	#losetup ${loop} ${path}
+
+	cryptsetup open --type plain --key-file /dev/urandom --key-size=256 --hash=sha256 --cipher=aes-cbc-essiv --offset=0  ${path} swapfile
+	SWAPDEV=/dev/mapper/swapfile
+else
+	SWAPDEV=$path
+fi
+
+## mkswap and swapon the device
+/sbin/mkswap $SWAPDEV
+/sbin/swapon $SWAPDEV