From f908a2c668bc9bf99a8c58fa0ed02b343f7b9ea6 Mon Sep 17 00:00:00 2001
From: Rob Berwick <rob.berwick@gmail.com>
Date: Sun, 23 Feb 2025 09:56:01 +0000
Subject: [PATCH] feat: enhance USB backend error handling with specific
 permission exception

---
 src/blinkstick/backends/unix_like.py | 36 ++++++++++++++++++----------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/src/blinkstick/backends/unix_like.py b/src/blinkstick/backends/unix_like.py
index db6179f..a953b5f 100644
--- a/src/blinkstick/backends/unix_like.py
+++ b/src/blinkstick/backends/unix_like.py
@@ -50,19 +50,29 @@ def get_attached_blinkstick_devices(
             raise USBBackendNotAvailable(
                 "Could not find USB backend. Is libusb installed?"
             )
-        return [
-            # TODO: refactor this to DRY up the usb.util.get_string calls
-            BlinkStickDevice(
-                raw_device=device,
-                serial_details=SerialDetails(
-                    serial=str(usb.util.get_string(device, 3, 1033))
-                ),
-                manufacturer=str(usb.util.get_string(device, 1, 1033)),
-                version_attribute=device.bcdDevice,
-                description=str(usb.util.get_string(device, 2, 1033)),
-            )
-            for device in raw_devices
-        ]
+
+        try:
+            devices = [
+                # TODO: refactor this to DRY up the usb.util.get_string calls
+                BlinkStickDevice(
+                    raw_device=device,
+                    serial_details=SerialDetails(
+                        serial=str(usb.util.get_string(device, 3, 1033))
+                    ),
+                    manufacturer=str(usb.util.get_string(device, 1, 1033)),
+                    version_attribute=device.bcdDevice,
+                    description=str(usb.util.get_string(device, 2, 1033)),
+                )
+                for device in raw_devices
+            ]
+        except usb.core.USBError as e:
+            # if the error is due to a permission issue, raise a more specific exception
+            if "Operation not permitted" in str(e):
+                raise USBBackendNotAvailable(
+                    "Permission denied accessing USB backend. Does a udev rule need to be added?"
+                )
+            raise
+        return devices
 
     @staticmethod
     def find_by_serial(serial: str) -> list[BlinkStickDevice[usb.core.Device]] | None: