Check if iommu_group devices path exists, before listing it.

src/pci_passthrough_assist/pci.py

@@ -1,5 +1,4 @@
 from os import listdir
-from os.path import realpath, basename
 
 
 def all_pci_device_ids() -> list[str]:
@@ -8,9 +7,3 @@ def all_pci_device_ids() -> list[str]:
 
 def all_pci_driver_ids() -> list[str]:
     return listdir("/sys/bus/pci/drivers")
-
-
-def driver_of_pci_device(pci_device_id: str) -> str:
-    driver_directory: str = realpath(
-        f"/sys/bus/pci/devices/{pci_device_id}/driver")
-    return basename(driver_directory)

src/pci_passthrough_assist/pci_device.py

@@ -1,15 +1,19 @@
-from pci_passthrough_assist.pci import driver_of_pci_device
-from os.path import exists
+from os.path import exists, realpath, basename
 from os import listdir
 
 
 class PciDevice:
 
     def __init__(self, device_id: str):
+        assert exists(f"/sys/bus/pci/devices/{device_id}")
         self.device_id = device_id
 
     def driver_name(self) -> str:
-        return driver_of_pci_device(self.device_id)
+        pci_driver_path = f"/sys/bus/pci/devices/{self.device_id}/driver"
+        if not exists(pci_driver_path):
+            return "NO-DRIVER-BOUND"
+        driver_directory: str = realpath(pci_driver_path)
+        return basename(driver_directory)
 
     def is_vga(self) -> bool:
         return exists(f"/sys/bus/pci/devices/{self.device_id}/boot_vga")
@@ -42,13 +46,20 @@ class PciDevice:
         if unbind_first:
             self.unbind_driver()
 
-        with open(f"/sys/bus/pci/drivers/{driver_to_bind}/bind",
-                  "w") as driver:
+        driver_bind_path = f"/sys/bus/pci/drivers/{driver_to_bind}/bind"
+        if not exists(driver_bind_path):
+            print(f"Can't bind to driver: {driver_bind_path}.")
+            return
+
+        with open(driver_bind_path, "w") as driver:
             driver.write(self.device_id)
 
     def devices_in_iommu_group(self) -> list['PciDevice']:
-        device_ids: list[str] = listdir(
-            f"/sys/bus/pci/devices/{self.device_id}/iommu_group/devices")
+        iommu_group_device_path = f"/sys/bus/pci/devices/{self.device_id}/iommu_group/devices"
+        if not exists(iommu_group_device_path):
+            print("Device does not have iommu_group devices.")
+            return []
+        device_ids: list[str] = listdir(iommu_group_device_path)
         return [PciDevice(device_id) for device_id in device_ids]
 
     def __str__(self) -> str: