server: detach gadget on stop

scripts/daemon/lesavka-core.sh

@@ -6,6 +6,65 @@
 set -euo pipefail
 
 log() { printf '[lesavka-core] %s\n' "$*"; }
+
+G=/sys/kernel/config/usb_gadget/lesavka
+
+find_udc() {
+    ls /sys/class/udc 2>/dev/null | head -n1 || true
+}
+
+detach_gadget() {
+    local udc=""
+    udc="$(find_udc)"
+    if [[ -n $udc && -w /sys/class/udc/$udc/soft_connect ]]; then
+        echo 0 >"/sys/class/udc/$udc/soft_connect" 2>/dev/null || true
+    fi
+    if [[ -e $G/UDC ]]; then
+        echo "" >"$G/UDC" 2>/dev/null || true
+    fi
+    if [[ -n $udc && -f /sys/class/udc/$udc/state ]]; then
+        local state
+        state="$(cat "/sys/class/udc/$udc/state" 2>/dev/null || true)"
+        log "detached (state=${state:-unknown})"
+    else
+        log "detached (no UDC state)"
+    fi
+}
+
+attach_gadget() {
+    if [[ ! -d $G ]]; then
+        log "gadget path missing; need full setup"
+        return 1
+    fi
+    local udc=""
+    udc="$(find_udc)"
+    if [[ -z $udc ]]; then
+        log "UDC not found; need full setup"
+        return 1
+    fi
+    if [[ -e $G/UDC ]]; then
+        echo "$udc" >"$G/UDC" 2>/dev/null || true
+    fi
+    log "attached to $udc"
+    return 0
+}
+
+case "${1:-}" in
+    --detach)
+        detach_gadget
+        exit 0
+        ;;
+    --attach)
+        if attach_gadget; then
+            exit 0
+        fi
+        ;;
+    --help|-h)
+        echo "Usage: $0 [--attach|--detach]"
+        exit 0
+        ;;
+esac
+
 cleanup() { echo "" >"$G/UDC" 2>/dev/null || true; }
 
 DISABLE_UAC=${LESAVKA_DISABLE_UAC:-}
@@ -100,7 +159,6 @@ log "✅ UDC detected: $UDC"
 # 3.  (Re‑)create gadget
 #──────────────────────────────────────────────────
 mountpoint -q /sys/kernel/config || mount -t configfs none /sys/kernel/config
-G=/sys/kernel/config/usb_gadget/lesavka
 
 if [[ -d $G ]]; then
   echo '' >"$G/UDC" 2>/dev/null || true

scripts/install/server.sh

@@ -166,7 +166,11 @@ Description=lesavka gRPC relay
 After=network.target lesavka-core.service
 
 [Service]
+ExecStartPre=/usr/local/bin/lesavka-core.sh --attach
 ExecStart=/usr/local/bin/lesavka-server
+ExecStopPre=/usr/local/bin/lesavka-core.sh --detach
+TimeoutStopSec=10
+KillSignal=SIGTERM
 Restart=always
 Environment=RUST_LOG=lesavka_server=info,lesavka_server::audio=info,lesavka_server::video=debug,lesavka_server::gadget=info
 Environment=RUST_BACKTRACE=1