Hibernation enablement script for Fedora

enable_hibernation.sh

#!/bin/bash
# Based on https://fedoramagazine.org/hibernation-in-fedora-36-workstation/
set -eo pipefail

ZRAM_KBYTES=$(cat /proc/swaps | grep zram0 | sed -E 's/\s+/\t/g' | cut -f 3)
TOTAL_RAM=$(free -k | egrep ^Mem: | sed -E "s/ +/\t/g" | cut -f2)
TOTAL_ZRAM=0
UNCOMPRESSED_RAM=${TOTAL_RAM}

for ZRAM in ${ZRAM_KBYTES}; do
    TOTAL_ZRAM=$(expr ${ZRAM} \* 2 + ${TOTAL_ZRAM})
    UNCOMPRESSED_RAM=$(expr ${UNCOMPRESSED_RAM} - ${ZRAM})
done
TOTAL_MEM_SPACE=$(expr ${TOTAL_ZRAM} + ${UNCOMPRESSED_RAM})

echo "MEMORY: ${TOTAL_MEM_SPACE} / ZRAM: ${TOTAL_ZRAM} / UNCOMPRESSED: ${UNCOMPRESSED_RAM}"

# Create swap file
btrfs subvolume create /swap
touch /swap/swapfile
chattr +C /swap/swapfile
fallocate --length ${TOTAL_MEM_SPACE}K /swap/swapfile
chmod 600 /swap/swapfile
mkswap /swap/swapfile
SWAP_UUID=$(findmnt -no UUID -T /swap/swapfile)

# Enable resume support in initramfs
cat <<-EOF | sudo tee /etc/dracut.conf.d/resume.conf
add_dracutmodules+=" resume "
EOF
dracut -f

curl -s https://raw.githubusercontent.com/osandov/osandov-linux/master/scripts/btrfs_map_physical.c -o btrfs_map_physical.c
gcc -Os -o /tmp/btrfs_map_physical btrfs_map_physical.c
SWAPFILE_OFFSET=$(/tmp/btrfs_map_physical /swap/swapfile | egrep ^0 | sed -E 's/\s+/\t/g' | cut -f9)
PAGESIZE=$(getconf PAGESIZE)
SWAPFILE_OFFSET_PAGES=$(expr ${SWAPFILE_OFFSET} / ${PAGESIZE})

echo "SWAP: UUID=${SWAP_UUID} OFFSET=${SWAPFILE_OFFSET_PAGES}"

grubby --args="resume=UUID=${SWAP_UUID} resume_offset=${SWAPFILE_OFFSET_PAGES}" --update-kernel=ALL

cat >/etc/systemd/system/hibernate-preparation.service <<-EOF
[Unit]
Description=Enable swap file and disable zram before hibernate
Before=systemd-hibernate.service

[Service]
User=root
Type=oneshot
ExecStart=/bin/bash -c "/usr/sbin/swapon /swap/swapfile && /usr/sbin/swapoff /dev/zram0"

[Install]
WantedBy=systemd-hibernate.service
EOF

cat >/etc/systemd/system/hibernate-resume.service <<-EOF
[Unit]
Description=Disable swap after resuming from hibernation
After=hibernate.target

[Service]
User=root
Type=oneshot
ExecStart=/usr/sbin/swapoff /swap/swapfile

[Install]
WantedBy=hibernate.target
EOF

systemctl enable hibernate-preparation.service
systemctl enable hibernate-resume.service

mkdir -p /etc/systemd/system/systemd-logind.service.d/ /etc/systemd/system/systemd-hibernate.service.d/
cat >/etc/systemd/system/systemd-logind.service.d/override.conf <<-EOF
[Service]
Environment=SYSTEMD_BYPASS_HIBERNATION_MEMORY_CHECK=1
EOF

cat >/etc/systemd/system/systemd-hibernate.service.d/override.conf <<-EOF
[Service]
Environment=SYSTEMD_BYPASS_HIBERNATION_MEMORY_CHECK=1
EOF