arch-system: add backup-system package

This implements fully automated, hourly backups of my /home via
borgbackup, btrfs and systemd timers.

Note that `setup_borgbackup`, a related function that is part of my
dotfiles, is needed to setup backups for the first time, as well as a
call to `borg init` with the proper environment variables.

1 files changed, 34 insertions, 0 deletions

diff --git a/arch-system/backup-sudo b/arch-system/backup-sudo
new file mode 100755
index 0000000..b2694b6
--- /dev/null
+++ b/arch-system/backup-sudo
@@ -0,0 +1,34 @@
+#!/bin/bash -e
+
+validate_path() {
+    # validate path
+    targetpath=$(realpath -m -- "$1")
+    if [[ "$targetpath" != /.snapshots/* ]]; then
+        echo "Invalid path given." >&2
+        exit 2
+    fi
+}
+
+case "$1" in
+    snapshot)
+        validate_path "$2"
+        btrfs subvolume snapshot -r -- /home "$2"
+        ;;
+    delete_snapshot)
+        validate_path "$2"
+        btrfs subvolume delete -- "$2"
+        ;;
+    mount)
+        validate_path "$2"
+        mkdir -p /backup
+        mount --bind -- "$2" /backup
+        ;;
+    cleanup)
+        umount /backup 2> /dev/null || true
+        rm -rf /backup
+        ;;
+    *)
+        echo "No command specified." >&2
+        exit 1
+        ;;
+esac