Created
June 2, 2014 16:43
-
-
Save oconnore/1b4876e716755cc83ae8 to your computer and use it in GitHub Desktop.
Encrypted swap
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/bin/sh | |
set -e | |
SWAPNAME="swapfile" | |
SWAPFILE="/var/swapfile.crypt" | |
MEMORY=`cat /proc/meminfo | grep MemTotal | sel -c 2` | |
# Next power of 2 Megabytes above reported memory | |
MEGABYTES=$(perl -e "use POSIX; print 2**ceil(log(ceil($MEMORY/(2**10)))/log(2))") | |
# status, on, or off | |
TYPE="$1" | |
if [ -z "$TYPE" ]; then | |
TYPE="status" | |
fi | |
enabled_p() { | |
SWAPS=$(sudo swapon -s | tail -n +2 | wc -l) | |
if [ $SWAPS -gt "0" ]; then | |
return 0; | |
else | |
return 1; | |
fi | |
} | |
status() { | |
# SWAPS=$(swapon -s | tail -n +2 | wc -l) | |
if enabled_p; then | |
swapon -s | tail -n +2 | sel -c 1 3 | xargs -n2 echo swap enabled | |
else | |
echo "swap disabled" | |
fi | |
} | |
cleanup() { | |
if [ -f /var/swap_loops ]; then | |
for loop_i in $(sudo cat /var/swap_loops); do | |
echo removing loopback $loop_i | |
sudo losetup -d "$loop_i" | |
done | |
sudo rm /var/swap_loops | |
fi | |
if sh -c "sudo cryptsetup status $SWAPNAME >/dev/null 2>&1"; then | |
echo closing crypto $SWAPNAME | |
sudo cryptsetup close $SWAPNAME | |
fi | |
} | |
make_swapfile() { | |
echo "creating a swap of size ${MEGABYTES}mB" | |
sudo dd if=/dev/zero of=$SWAPFILE bs=1M count=$MEGABYTES | |
} | |
ensure_swapfile() { | |
if [ -f $SWAPFILE ]; then | |
SIZE=$(ls -l $SWAPFILE | sel -c 5) | |
MBACT=$(perl -e "use POSIX; print floor($SIZE/1048576)") | |
if [ "$MBACT" -lt "$MEGABYTES" ]; then | |
make_swapfile | |
fi | |
else | |
make_swapfile | |
fi | |
sudo chmod 600 $SWAPFILE | |
} | |
# run main operations | |
if [ "$TYPE" = "status" ]; then | |
status | |
elif [ "$TYPE" = "on" ]; then | |
if enabled_p; then | |
status | |
else | |
cleanup | |
ensure_swapfile | |
LOOP=$(sudo losetup -f) | |
echo using loopback device $LOOP | |
sudo sh -c "echo $LOOP >> /var/swap_loops" | |
sudo losetup $LOOP $SWAPFILE | |
echo setting up crypto | |
sudo cryptsetup open --type plain --key-file /dev/urandom $LOOP $SWAPNAME | |
echo mkswap on /dev/mapper/$SWAPNAME | |
sudo mkswap -f /dev/mapper/$SWAPNAME | |
echo swapon on /dev/mapper/$SWAPNAME | |
sudo swapon /dev/mapper/$SWAPNAME | |
status | |
fi | |
elif [ "$TYPE" = "off" ]; then | |
for swap_i in $(swapon -s | tail -n +2 | sel -c 1); do | |
echo swapoff on $swap_i | |
sudo swapoff $swap_i | |
done | |
cleanup | |
status | |
fi | |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
on Ubuntu 14.04 LTS