rego-tunnel: default TSCLIENT to APP_DATA_DIR + auto-mount 9p

apps/rego-tunnel/build/start-vm.sh

@@ -28,6 +28,56 @@ TAP_NAME="${TAP_NAME:-tap0}"
 # Optional: provide a dedicated 9p export for host app-data (bind-mounted into the container at /shared/app-data)
 TSCLIENT_PATH="/hostshare"
 TSCLIENT_TAG="${TSCLIENT_TAG:-TSCLIENT}"
+SHARED_TAG="${SHARED_TAG:-shared}"
+
+# Ensure the VM auto-mounts the 9p shares without manual steps.
+# This edits the QCOW2 from the outside (idempotent) before QEMU boots.
+AUTO_MOUNT_9P="${AUTO_MOUNT_9P:-1}"
+if [ "$AUTO_MOUNT_9P" = "1" ]; then
+	QCOW2_PATH="/vm/linux-vm.qcow2"
+	NBD_DEV="${NBD_DEV:-/dev/nbd0}"
+	VMROOT_MNT="/mnt/vmroot"
+
+	if [ -e "$QCOW2_PATH" ] && [ -e "$NBD_DEV" ]; then
+		echo "[rego-tunnel] Ensuring guest fstab mounts 9p tags ($SHARED_TAG, $TSCLIENT_TAG)"
+		modprobe nbd max_part=16 >/dev/null 2>&1 || true
+		qemu-nbd --disconnect "$NBD_DEV" >/dev/null 2>&1 || true
+		qemu-nbd --connect "$NBD_DEV" "$QCOW2_PATH"
+		sleep 1
+
+		mkdir -p "$VMROOT_MNT"
+		ROOT_PART=""
+		for part in "${NBD_DEV}"p*; do
+			[ -e "$part" ] || continue
+			# Try mount and detect a Linux root by presence of /etc/fstab and /etc/os-release
+			if mount "$part" "$VMROOT_MNT" >/dev/null 2>&1; then
+				if [ -f "$VMROOT_MNT/etc/fstab" ] && [ -f "$VMROOT_MNT/etc/os-release" ]; then
+					ROOT_PART="$part"
+					break
+				fi
+				umount "$VMROOT_MNT" >/dev/null 2>&1 || true
+			fi
+		done
+
+		if [ -n "$ROOT_PART" ]; then
+			# already mounted from loop above
+			mkdir -p "$VMROOT_MNT/shared" "$VMROOT_MNT/mnt/TSCLIENT"
+
+			FSTAB="$VMROOT_MNT/etc/fstab"
+			# Add entries only if missing
+			grep -qE "^[[:space:]]*${SHARED_TAG}[[:space:]]+" "$FSTAB" || echo "${SHARED_TAG} /shared 9p trans=virtio,version=9p2000.L,msize=262144,_netdev,nofail,x-systemd.automount 0 0" >> "$FSTAB"
+			grep -qE "^[[:space:]]*${TSCLIENT_TAG}[[:space:]]+" "$FSTAB" || echo "${TSCLIENT_TAG} /mnt/TSCLIENT 9p trans=virtio,version=9p2000.L,msize=262144,_netdev,nofail,x-systemd.automount 0 0" >> "$FSTAB"
+
+			umount "$VMROOT_MNT" >/dev/null 2>&1 || true
+		else
+			echo "[rego-tunnel] WARN: could not locate guest root partition; skipping auto-mount setup"
+		fi
+
+		qemu-nbd --disconnect "$NBD_DEV" >/dev/null 2>&1 || true
+	else
+		echo "[rego-tunnel] WARN: missing $QCOW2_PATH or $NBD_DEV; skipping auto-mount setup"
+	fi
+fi
 
 exec qemu-system-x86_64 \
 	-enable-kvm \
@@ -36,7 +86,7 @@ exec qemu-system-x86_64 \
 	-smp ${VM_CPUS:-4} \
 	-hda /vm/linux-vm.qcow2 \
 	-fsdev local,id=fsdev0,path=/shared,security_model=none,multidevs=remap \
-	-device virtio-9p-pci,fsdev=fsdev0,mount_tag=shared \
+	-device virtio-9p-pci,fsdev=fsdev0,mount_tag="$SHARED_TAG" \
 	-fsdev local,id=fsdev1,path="$TSCLIENT_PATH",security_model=none,multidevs=remap \
 	-device virtio-9p-pci,fsdev=fsdev1,mount_tag="$TSCLIENT_TAG" \
 	-netdev tap,id=net0,ifname="$TAP_NAME",script=no,downscript=no \