From d9804a00d1d2164f5c25d743d18bd4f6a8776f31 Mon Sep 17 00:00:00 2001
From: Max Christian Pohle
Date: Wed, 6 May 2020 00:01:37 +0200
Subject: Added automatic backup script

This is WIP and should not be used by anybody until I have fixed hard
coded paths and stuff like that.

The idea of this script is: Once you plug a disk drive in, it will
automatically be backed up, but only if a zfs dataset with the name of
that drive already exists.
---
 backup/backup.sh                            | 75 +++++++++++++++++++++++++++++
 backup/systemd/max-backup@.service          |  8 +++
 backup/udev/rules.d/99-max-autobackup.rules |  2 +
 3 files changed, 85 insertions(+)
 create mode 100755 backup/backup.sh
 create mode 100644 backup/systemd/max-backup@.service
 create mode 100644 backup/udev/rules.d/99-max-autobackup.rules

diff --git a/backup/backup.sh b/backup/backup.sh
new file mode 100755
index 0000000..91acdfc
--- /dev/null
+++ b/backup/backup.sh
@@ -0,0 +1,75 @@
+#!/usr/bin/bash
+logger "================================================================================"
+
+# BACKUP_NAME=$ID_SERIAL-part$ID_PART_ENTRY_NUMBER
+BACKUP_NAME=$(echo $1 | sed -e 's/\\x2d/-/g')
+MOUNT_TARGET=/media/$BACKUP_NAME
+
+function fail() {
+    logger -s -t "$0" "Backup '$1' -> '$2' failed."
+    sudo -u max beep -f 40 -l 500
+    # sudo -u max beep -f 523 -l 150 -n -f 54 -l 600
+}
+
+function start() {
+    DEVNAME=$(echo $1 | sed 's/-/\\x2d/')
+    systemctl restart media-$DEVNAME.automount
+
+    logger -t "$0" "Backup '$1' -> '$2' started."
+    sudo -u max beep -f 147 -l 120 -n -f 294 -l 200 -n -f 831
+}
+
+function stop() {
+    DEVNAME=$(echo $1 | sed 's/-/\\x2d/')
+    systemctl stop media-$DEVNAME.automount
+
+    logger -t "$0" "Backup '$1' -> '$2' finished."
+    sudo -u max beep -f 831 -l 120 -n -f 294 -l 200 -n -f 147
+}
+
+function zfs_snapshot() {
+    zfs diff $LAST_SNAPSHOT > $ZFS_PATH/backup-differences.txt
+    zfs snap media-backup/$BACKUP_NAME@$(date +%Y-%m-%d--%H-%M)
+    echo "Here comes a list of changes since your last backup: $LAST_SNAPSHOT" | mailx -A typesafe -a $ZFS_PATH/backup-differences.txt -s 'Backup overview' max@entwicklerseite.de
+}
+
+start $1
+
+if ! findmnt $MOUNT_TARGET; then
+    logger "$MOUNT_TARGET is not mounted. Cannot back it up."
+    exit 0
+fi
+
+logger ">> Inspecting $BACKUP_NAME"
+ZFS_PATH=$(zfs get mountpoint -H -o value media-backup/$BACKUP_NAME) || fail "$MOUNT_TARGET" "(no zfs dataset found)"
+ZFS_MOUNTPATH=$(findmnt -no source $ZFS_PATH)                        || fail "$ZFS_PATH (not mounted)" "(no association)"
+LAST_SNAPSHOT=$(zfs list -t snap -o name -s creation media-backup/$BACKUP_NAME | tail -n1)
+
+
+# Make sure, that we are really writing where a mountpoint is
+if [ "$ZFS_PATH" == "/$ZFS_MOUNTPATH" ]; then
+    sudo -u max beep -f 831
+    logger "We can start $MOUNT_TARGET -> $ZFS_PATH"
+    rsync -ahoi -x --delete --info=all \
+        "/media/$BACKUP_NAME/"      \
+        "$ZFS_PATH"                 \
+        2>&1 | tee $ZFS_PATH/backup-report.txt && zfs_snapshot
+
+else
+    fail $ZFS_PATH $ZFS_MOUNTPATH
+    exit 1
+fi
+
+
+
+stop $1
+
+# sleep a second so that /dev/disk/by-id/*-part become available
+# sleep 1
+
+# DISK=$(readlink -f /dev/disk/by-id/$ID_BUS-$ID_SERIAL)
+# if ! [ -e "$DISK" ]; then
+#     fail
+#     logger "$DISK: Disk not there :("
+#     exit 1
+# fi
diff --git a/backup/systemd/max-backup@.service b/backup/systemd/max-backup@.service
new file mode 100644
index 0000000..44c6bf8
--- /dev/null
+++ b/backup/systemd/max-backup@.service
@@ -0,0 +1,8 @@
+[Unit]
+Description=Generic backup
+
+[Service]
+Type=simple
+ExecStart=/home/max/backup/backup.sh %I
+
+
diff --git a/backup/udev/rules.d/99-max-autobackup.rules b/backup/udev/rules.d/99-max-autobackup.rules
new file mode 100644
index 0000000..e17bba0
--- /dev/null
+++ b/backup/udev/rules.d/99-max-autobackup.rules
@@ -0,0 +1,2 @@
+ACTION=="add", ENV{ID_PART_ENTRY_NUMBER}=="[0-9]", ENV{SYSTEMD_WANTS}="max-backup@$env{ID_SERIAL}\\x2dpart$env{ID_PART_ENTRY_NUMBER}.service" 
+LABEL="External disk drive backup"
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