From ec6cf92eb0da7ad8ceee1dd57c7a6b9ff091c940 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1s=20Migone?= <tomas@balena.io>
Date: Thu, 2 Dec 2021 13:31:34 -0300
Subject: [PATCH] Support initiating pairing for devices that can't do it
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Change-type: minor
Signed-off-by: Tomás Migone <tomas@balena.io>
---
 README.md       |  8 ++++++++
 bluetooth-agent |  3 +--
 entry.sh        | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index a2e69ab..6994d0b 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,14 @@ The following environment variables allow some degree of configuration:
 | `BLUETOOTH_HCI_INTERFACE` | The bluetooth interface to be used. | `hci0` | - |
 | `BLUETOOTH_PAIRING_MODE` | The bluetooth paring mode:<br>- Secure Simple Pairing (SSP): Secure pinless pairing method<br>- Legacy Pairing: PIN code based authentication. Less secure but older devices might only support this mode. Note that this mode is no longer allowed on [iOS](https://developer.apple.com/accessories/Accessory-Design-Guidelines.pdf) devices. | `SSP` | `SSP`, `LEGACY` |
 | `BLUETOOTH_PIN_CODE` | PIN code used for Legacy Pairing. Must be numeric and up to six digits (1 - 999999). | `0000` | - |
+| `BLUETOOTH_CONNECT_DEVICE` | Initiate pairing with a device using the provided MAC address. Useful for devices that can't initiate the pairing process like bluetooth headsets. *| - | - |
+
+*: You can find the MAC address by checking the logs of the bluetooth block. Look for a line with your device's name, the address will be on the previous line. For example, in this case `70:BF:12:F6:91:24` is the MAC address of the `Jabra Evolve 75` headset
+
+```
+[bluetooth] hci0 dev_found: 70:BF:12:F6:91:24 type BR/EDR rssi -29 flags 0x0000 
+[bluetooth] name Jabra Evolve 75
+```
 
 ## Supported devices
 The bluetooth block has been tested to work on the following devices:
diff --git a/bluetooth-agent b/bluetooth-agent
index a7e58e6..295d2c5 100644
--- a/bluetooth-agent
+++ b/bluetooth-agent
@@ -158,10 +158,9 @@ if __name__ == "__main__":
     bluez_objects = bluez_manager.GetManagedObjects()
     device_paths = dbus_filter_objects_by_interface(bluez_objects, "org.bluez.Device1")
 
-    print("Checking for known bluetooth devices...")
     for device_path in device_paths:
         props = dbus_get_all_properties("org.bluez", device_path, "org.bluez.Device1")
-        if bool(props["Paired"]) and bool(props["Trusted"]):
+        if bool(props["Paired"]):
             print("- Attempting to reconnect to %s (%s)..." % (props["Name"], props["Address"]))
 
             # Try to reconnect...
diff --git a/entry.sh b/entry.sh
index 5e98136..a3df591 100644
--- a/entry.sh
+++ b/entry.sh
@@ -18,6 +18,7 @@ DEVICE_NAME=${BLUETOOTH_DEVICE_NAME:-$(printf "balenaOS %s"$(echo "$BALENA_DEVIC
 HCI_INTERFACE=${BLUETOOTH_HCI_INTERFACE:-"hci0"}
 PAIRING_MODE=${BLUETOOTH_PAIRING_MODE:-"SSP"}
 PIN_CODE=${BLUETOOTH_PIN_CODE:-"0000"}
+CONNECT_DEVICE="$BLUETOOTH_CONNECT_DEVICE"
 
 echo "--- Bluetooth ---"
 echo "Starting bluetooth service with settings:"
@@ -66,6 +67,38 @@ else
   echo "Pairing mode set to 'Secure Simple Pairing Mode (SSPM)'. PIN code is NOT required."
 fi
 
+# Handle pairing with devices that can't initiate the pairing process
+# Single device allowed via BLUETOOTH_CONNECT_DEVICE
+# Bluetooth connection is handled by bluetooth-agent
+if [[ -n "$CONNECT_DEVICE" ]]; then
+  echo "Bluetooth connect device provided, initiating pairing with device: $CONNECT_DEVICE"
+  PAIRED=$(bluetoothctl -- paired-devices | grep "$CONNECT_DEVICE" || echo "")
+
+  if [[ -z "$PAIRED" ]]; then
+    echo "Scanning for bluetooth devices... please set your device to pairing mode"
+    btmgmt --index $HCI_INTERFACE find
+    sleep 10
+  
+    for i in {1..5}
+    do
+      echo "($i/5) Attempting to pair with device: $CONNECT_DEVICE"
+      btmgmt --index $HCI_INTERFACE pair "$CONNECT_DEVICE"
+
+      PAIRED=$(bluetoothctl -- paired-devices | grep "$CONNECT_DEVICE" || echo "")
+      if [[ -n "$PAIRED" ]]; then
+        break
+      fi
+
+      sleep 10
+    done
+
+    btmgmt --index $HCI_INTERFACE stop-find
+    echo "Scanning off"
+  else
+    echo "Device already paired: $CONNECT_DEVICE"
+  fi
+fi
+
 # If command starts with an option, prepend bluetooth-agent to it
 if [[ "${1#-}" != "$1" ]]; then
   set -- bluetooth-agent "$@"