feat(waybar): add webcam privacy indicator

V4L2 capture goes directly through /dev/videoN and never traverses
the PipeWire portal, so the built-in privacy module misses it. New
custom/webcam module polls fuser on /dev/video* every 2s and shows
a red 'CAM' badge when any device is held open.

Empty text when idle, so the slot collapses and stays out of the way
when the webcam is unused (i.e. always, on a usual day).

1 files changed, 18 insertions, 0 deletions

diff --git a/dot_config/waybar/executable_webcam-status.sh b/dot_config/waybar/executable_webcam-status.sh
new file mode 100644
index 0000000..b8e5570
--- /dev/null
+++ b/dot_config/waybar/executable_webcam-status.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+# Emit waybar JSON when any /dev/video* device is held open by a process.
+# V4L2 capture (firefox, zoom, OBS, etc.) doesn't go through PipeWire's
+# privacy portal, so the built-in waybar privacy module never sees it.
+set -eu
+
+devs=$(echo /dev/video[0-9]*)
+case "$devs" in
+  '/dev/video[0-9]*') exit 0 ;;  # no devices present
+esac
+
+# fuser exits 0 when at least one device has an opener, 1 otherwise. Stderr
+# carries 'PID' for each match; redirect it away.
+if fuser $devs >/dev/null 2>&1; then
+  printf '{"text":"CAM","tooltip":"webcam in use","class":"active","alt":"active"}\n'
+else
+  printf '{"text":"","alt":"idle"}\n'
+fi