Use shell script instead of OS Agent for device wipe (#3916)

Use simple shell script to perform device wipe instead of calling OS Agent to
do that through the UDisks2 API. While it might have been a good idea to use
high level interface for that back then, it turns out it causes more issues
than the benefits it could bring.

Main problem currently is that the OS Agent needs to read sysctl variables, but
those are only set after mounting the overlay partition. But at the same time,
the overlay partition can't be mounted if we want to wipe it - this creates a
dependency cycle through the haos-agent.service.

To get rid of the cycle and simplify things, use a shell script doing basically
the same what the OS Agent does. Since the wipe functionality only makes sense
to be implemented on HAOS targets (not on Supervised), there's little point of
having it in higher layer of abstraction that OS Agent provides.

It should be also checked if changes from #1291 are needed anymore, as the
driving factor for those have been probably the wipe feature in OS Agent too,
but at this point they seem to be harmless.

buildroot-external/rootfs-overlay/usr/lib/systemd/system/haos-wipe.service

@@ -4,15 +4,13 @@ DefaultDependencies=no
 RefuseManualStart=true
 RefuseManualStop=true
 Wants=mnt-boot.mount
-Requires=haos-agent.service
-After=haos-agent.service mnt-boot.mount
+After=mnt-boot.mount
 Before=mnt-data.mount mnt-overlay.mount
 ConditionKernelCommandLine=haos.wipe=1
 
 [Service]
 Type=oneshot
-ExecStart=/usr/bin/busctl --verbose --timeout=1h call io.hass.os /io/hass/os/System io.hass.os.System WipeDevice
-ExecStartPost=/usr/bin/sed -i 's/\s*haos.wipe=1//g' /mnt/boot/cmdline.txt
+ExecStart=/usr/libexec/haos-wipe
 
 [Install]
 WantedBy=sysinit.target

buildroot-external/rootfs-overlay/usr/libexec/haos-wipe

@@ -0,0 +1,30 @@
+#!/bin/sh
+set -e
+
+PARTITION_OVERLAY="/dev/disk/by-label/hassos-overlay"
+PARTITION_DATA="/dev/disk/by-label/hassos-data"
+
+if [ ! -b "$PARTITION_OVERLAY" ]; then
+    echo "[ERROR] Overlay partition not found"
+    exit 1
+elif findmnt "$PARTITION_OVERLAY" > /dev/null; then
+    echo "[ERROR] Unable to wipe overlay partition while it is already mounted"
+    exit 1
+fi
+
+if [ ! -b "$PARTITION_DATA" ]; then
+    echo "[ERROR] Data partition not found"
+    exit 1
+elif findmnt "$PARTITION_DATA" > /dev/null; then
+    echo "[ERROR] Unable to wipe data partition while it is already mounted"
+    exit 1
+fi
+
+echo "[INFO] Wiping data partition"
+mkfs.ext4 -L "hassos-data" -E lazy_itable_init=0,lazy_journal_init=0 "$PARTITION_DATA"
+
+echo "[INFO] Wiping overlay partition"
+mkfs.ext4 -L "hassos-overlay" -I 256 -E lazy_itable_init=0,lazy_journal_init=0 "$PARTITION_OVERLAY"
+
+echo "[INFO] Removing wipe flag from cmdline.txt"
+/usr/bin/sed -i 's/\s*haos.wipe=1//g' /mnt/boot/cmdline.txt