udev: split wifi and bt rules into two separate files, add systemd unit file, and add BT mac retry

The udev rule for bluetooth doesn't work on systemd[1], by splitting the rule into two separate rules, distros can leave this bluetooth rule out when packaging for systemd.

Distros packaging bootmac will have to make note of the new rule files/names.

This also includes a systemd unit file that can be used to autostart bootmac when bluetooth stuff is starting up (e.g. when the adapter is available), and provides a nicer way to add delays instead of trying to delay udev scripts, scripts that take 'too long' for udev can cause problems.

1. https://github.com/systemd/systemd/issues/35003

bootmac

@@ -16,9 +16,18 @@ WLAN_INTERFACE="wlan0"
 BT_INTERFACE="hci0"
 # Default MAC prefix
 MAC_PREFIX="0200"
+BT_TIMEOUT=${BT_TIMEOUT:-5} # seconds
+WLAN_TIMEOUT=${WLAN_TIMEOUT:-5} # seconds
+
+USE_LOGGER=true
+[ -n "$SYSTEMD_EXEC_PID" ] && USE_LOGGER=false
 
 log() {
-    echo "$@" | logger -t "bootmac"
+    if "$USE_LOGGER"; then
+        echo "$@" | logger -t "bootmac"
+    else
+        echo "$@"
+    fi
 }
 
 help_info() {
@@ -141,9 +150,6 @@ mac_generate() {
 }
 
 mac_bluetooth() {
-    # Some Bluetooth adapters take time before they can be configured
-    sleep 1
-
     log "setting Bluetooth MAC to $BT_MAC"
 
     # Check if the Bluetooth interface is up
@@ -162,7 +168,24 @@ mac_bluetooth() {
     # The 'yes | btmgmt xxx' workaround is needed for proper working of btmgmt
     # as noted in https://gitlab.com/postmarketOS/bootmac/-/issues/3
     yes | btmgmt -i "$BT_INTERFACE" power off
-    yes | btmgmt -i "$BT_INTERFACE" public-addr "$BT_MAC"
+
+    # Setting the mac addr might fail if the device/driver hasn't finished
+    # initializing, so retry
+    timeout=0
+    while [ $timeout -lt "$BT_TIMEOUT" ]; do
+        if yes | btmgmt -i "$BT_INTERFACE" public-addr "$BT_MAC"; then
+            break
+        fi
+        log "Unable to set Bluetooth MAC, retrying after 1 second..."
+        sleep 1
+        timeout=$((timeout + 1))
+    done
+
+    if [ $timeout -ge "$BT_TIMEOUT" ]; then
+        log "Failed to set Bluetooth MAC address, command timed out after $BT_TIMEOUT seconds"
+        return 1
+    fi
+
     if [ -n "$BT_RFKILL_UNBLOCKED" ]; then
         log "restoring Bluetooth rfkill state to unblocked"
         rfkill unblock bluetooth
@@ -180,8 +203,24 @@ mac_wlan() {
     set -e
 
     # Bring WLAN down, set the extracted MAC and bring it up again
-    ip link set dev "$WLAN_INTERFACE" down
-    ip link set dev "$WLAN_INTERFACE" address "$WLAN_MAC"
+    # Setting the mac addr might fail if the device/driver hasn't finished
+    # initializing, so retry
+    timeout=0
+    while [ $timeout -lt "$WLAN_TIMEOUT" ]; do
+        if ip link set dev "$WLAN_INTERFACE" down \
+                && ip link set dev "$WLAN_INTERFACE" address "$WLAN_MAC" ; then
+            break
+        fi
+        log "Unable to set wlan MAC, retrying after 1 second..."
+        sleep 1
+        timeout=$((timeout + 1))
+    done
+
+    if [ $timeout -ge "$WLAN_TIMEOUT" ]; then
+        log "Failed to set wlan MAC address, command timed out after $WLAN_TIMEOUT seconds"
+        return 1
+    fi
+
     if [ -n "$WLAN_RFKILL_UNBLOCKED" ]; then
       log "restoring WLAN rfkill state to unblocked"
       rfkill unblock wlan