USB rebind via sudo tee (permission sysfs requiert root)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/main.py

@@ -124,8 +124,9 @@ def _usb_reset_canon():
 
 
 def _usb_rebind_canon():
-    """Unbind/rebind USB Canon — simule un debranchement/rebranchement physique."""
-    import glob
+    """Unbind/rebind USB Canon — simule un debranchement/rebranchement physique.
+    Necessite sudoers NOPASSWD pour tee sur /sys/bus/usb/drivers/usb/{un,}bind."""
+    import glob, subprocess, time
     try:
         for f in glob.glob("/sys/bus/usb/devices/*/idVendor"):
             if open(f).read().strip() == "04a9":
@@ -133,12 +134,15 @@ def _usb_rebind_canon():
                     __import__("os.path", fromlist=["dirname"]).dirname(f)
                 )
                 log.info(f"USB rebind Canon: unbind {dev_id}")
-                with open("/sys/bus/usb/drivers/usb/unbind", "w") as fh:
-                    fh.write(dev_id)
-                import time
+                subprocess.run(
+                    ["sudo", "tee", "/sys/bus/usb/drivers/usb/unbind"],
+                    input=dev_id.encode(), stdout=subprocess.DEVNULL, timeout=5,
+                )
                 time.sleep(2)
-                with open("/sys/bus/usb/drivers/usb/bind", "w") as fh:
-                    fh.write(dev_id)
+                subprocess.run(
+                    ["sudo", "tee", "/sys/bus/usb/drivers/usb/bind"],
+                    input=dev_id.encode(), stdout=subprocess.DEVNULL, timeout=5,
+                )
                 log.info(f"USB rebind Canon: bind {dev_id}")
                 time.sleep(3)
                 return True