default appliance: restore some config and users from theDATA volume

appliances/default/Makefile

@@ -39,7 +39,7 @@ $(PAM_SSH_AGENT_AUTH):
 	touch $(PAM_SSH_AGENT_AUTH)
 
 $(ADMINUSER):
-	RUN useradd -m -G users,wheel -s /bin/bash --comment="virtual appliance admin" --uid 2000 admin
+	-RUN useradd -m -G users,wheel -s /bin/bash --comment="virtual appliance admin" --uid 2000 admin
 	RUN passwd -d admin; $(inroot) passwd -e admin
 	touch $(ADMINUSER)
 

appliances/default/default/01firstboot.start

@@ -33,4 +33,46 @@ if ! mount | grep /$LABEL > /dev/null; then
     exit 1
 fi
 
+if [ -d "/$LABEL/home" ]; then
+    cd "/$LABEL/home"
+    for user in *; do
+        if [ -d "$user" ]; then
+            if ! id -u "$user" >/dev/null 2>&1; then
+                useradd -m -G users,wheel -s /bin/bash --uid $(stat -c '%u' $user) --user-group $user
+            fi
+            rm -rf "/home/$user"
+            ln -nsf "/$LABEL/home/$user" "/home/$user"
+        fi
+    done
+fi
+
+if [ -d "/$LABEL/etc/ssh" ]; then
+    rm -rf /etc/ssh
+    ln -nsf "/$LABEL/etc/ssh" /etc/ssh
+    systemctl restart sshd
+else
+    mkdir -p "/$LABEL/etc"
+    mv /etc/ssh "/$LABEL/etc/"
+    ln -nsf "/$LABEL/etc/ssh" /etc/ssh
+fi
+
+if [ -f "/$LABEL/etc/hosts" ]; then
+    rm -f /etc/hosts
+    ln -nsf "/$LABEL/etc/hosts" /etc/hosts
+else
+    mkdir -p "/$LABEL/etc"
+    mv -f /etc/hosts "/$LABEL/etc/hosts"
+    cp -f "/$LABEL/etc/hosts" "/$LABEL/etc/hosts.orig"
+    ln -nsf "/$LABEL/etc/hosts" /etc/hosts
+fi
+
+if [ -f "/$LABEL/etc/fstab" ]; then
+    cp -f "/$LABEL/etc/fstab" /etc/fstab
+fi
+
+if [ -d "/$LABEL/etc/systemd" ]; then
+    cp -a "/$LABEL/etc/systemd" /etc/
+    systemctl daemon-reload
+fi
+
 rm /01firstboot