Rewrite USB logic

We're not actually using libusb for anything, so in this commit we drop
all usage of libusb and CGO_ENABLED=1 to make things more portable.

To find USB devices we scan /sys/bus/usb/devices/* to find devices,
matching on idVendor and idProduct.

Signed-off-by: Fredrik Lönnegren <[email protected]>

Author: frelon

Dockerfile.device-plugin

@@ -1,9 +1,8 @@
 # Build the manager binary
-FROM registry.opensuse.org/opensuse/tumbleweed:latest AS builder
+FROM --platform=$BUILDPLATFORM golang:1.25 AS builder
 ARG TARGETOS
 ARG TARGETARCH
 
-RUN zypper --non-interactive install --no-recommends go libusb-1_0-devel
 WORKDIR /workspace
 
 COPY go.mod go.mod
@@ -12,10 +11,10 @@ RUN go mod download
 
 COPY cmd/device-plugin/main.go cmd/device-plugin/main.go
 COPY device-plugin device-plugin
-RUN CGO_ENABLED=1 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build -a -o deviceplugin cmd/device-plugin/main.go
+RUN CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build -a -o deviceplugin cmd/device-plugin/main.go
 
-FROM registry.opensuse.org/opensuse/tumbleweed:latest
-RUN zypper --non-interactive install --no-recommends libusb-1_0-0
-WORKDIR /root
+FROM gcr.io/distroless/static:latest
+WORKDIR /
 COPY --from=builder /workspace/deviceplugin .
+
 ENTRYPOINT ["./deviceplugin", "-logtostderr=true", "-stderrthreshold=INFO", "-v=5"]

cmd/device-plugin/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"log/slog"
+	"os"
 	"time"
 
 	"github.com/kubevirt/device-plugin-manager/pkg/dpm"
@@ -32,10 +33,7 @@ func (l *RadioDeviceLister) Discover(pluginListCh chan dpm.PluginNameList) {
 
 func (l *RadioDeviceLister) NewPlugin(resourceLastName string) dpm.PluginInterface {
 	if resourceLastName == rtlsdr.ResourceName {
-		return &rtlsdr.Plugin{
-			Heartbeat: l.Heartbeat,
-			RtlSdrs:   make(map[string]*rtlsdr.RtlSdrDev),
-		}
+		return rtlsdr.NewPlugin(l.Heartbeat, os.DirFS("/"))
 	}
 
 	slog.Error("Unknown resource", "name", resourceLastName)

device-plugin/rtl-sdr/rtl-sdr.go

@@ -2,93 +2,92 @@ package rtlsdr
 
 import (
 	"context"
-	"fmt"
+	"io/fs"
 	"log/slog"
 
-	"github.com/google/gousb"
 	pluginapi "k8s.io/kubelet/pkg/apis/deviceplugin/v1beta1"
 )
 
 const (
 	ResourceName = "rtl-sdr"
 )
 
-type Plugin struct {
-	RtlSdrs   map[string]*RtlSdrDev
-	Heartbeat chan bool
+type plugin struct {
+	devices   map[string]*UsbDevice
+	heartbeat chan bool
+	fsys      fs.FS
 }
 
-func (p *Plugin) GetDevicePluginOptions(ctx context.Context, e *pluginapi.Empty) (*pluginapi.DevicePluginOptions, error) {
+func NewPlugin(heartbeat chan bool, fsys fs.FS) *plugin {
+	return &plugin{
+		heartbeat: heartbeat,
+		fsys:      fsys,
+		devices:   make(map[string]*UsbDevice),
+	}
+}
+
+func (p *plugin) GetDevicePluginOptions(ctx context.Context, e *pluginapi.Empty) (*pluginapi.DevicePluginOptions, error) {
 	return &pluginapi.DevicePluginOptions{}, nil
 }
 
-func (p *Plugin) PreStartContainer(ctx context.Context, r *pluginapi.PreStartContainerRequest) (*pluginapi.PreStartContainerResponse, error) {
+func (p *plugin) PreStartContainer(ctx context.Context, r *pluginapi.PreStartContainerRequest) (*pluginapi.PreStartContainerResponse, error) {
 	return &pluginapi.PreStartContainerResponse{}, nil
 }
 
-func (p *Plugin) UpdateDevices() error {
-	rtls, err := ListDevices()
+func (p *plugin) UpdateDevices() ([]*pluginapi.Device, error) {
+	connectedDevs, err := ListUsbDevices(p.fsys)
 	if err != nil {
 		slog.Info("Error listing devices", slog.Any("error", err))
-		return err
+		return nil, err
 	}
 
-	slog.Info("Found devices", "len", len(rtls))
+	slog.Info("Found devices", "len", len(connectedDevs))
 
-	for _, rtl := range p.RtlSdrs {
-		rtl.Connected = false
+	connectedDevsBySerial := map[string]*UsbDevice{}
+	for i := range connectedDevs {
+		connectedDevsBySerial[connectedDevs[i].Serial] = connectedDevs[i]
+		p.devices[connectedDevs[i].Serial] = connectedDevs[i]
 	}
 
-	for i := range rtls {
-		p.RtlSdrs[rtls[i].SerialNumber] = rtls[i]
-	}
-
-	return nil
-}
-
-func (p *Plugin) GetDevices() []*pluginapi.Device {
-	devs := make([]*pluginapi.Device, len(p.RtlSdrs))
+	pdevs := make([]*pluginapi.Device, len(p.devices))
 	i := 0
-	for _, rtl := range p.RtlSdrs {
-		devs[i] = &pluginapi.Device{
-			ID:     rtl.SerialNumber,
+	for _, rtl := range p.devices {
+		pdevs[i] = &pluginapi.Device{
+			ID:     rtl.Serial,
 			Health: pluginapi.Unhealthy,
 		}
 
-		if rtl.Connected {
-			devs[i].Health = pluginapi.Healthy
+		if _, ok := connectedDevsBySerial[rtl.Serial]; ok {
+			pdevs[i].Health = pluginapi.Healthy
 		}
 
 		i++
 	}
 
-	return devs
+	return pdevs, nil
 }
 
-func (p *Plugin) ListAndWatch(e *pluginapi.Empty, s pluginapi.DevicePlugin_ListAndWatchServer) error {
-	err := p.UpdateDevices()
+func (p *plugin) ListAndWatch(e *pluginapi.Empty, s pluginapi.DevicePlugin_ListAndWatchServer) error {
+	devs, err := p.UpdateDevices()
 	if err != nil {
 		slog.Error("Error listing devices", slog.Any("error", err))
 	}
 
-	devs := p.GetDevices()
-
 	err = s.Send(&pluginapi.ListAndWatchResponse{Devices: devs})
 	if err != nil {
 		slog.Error("Error sending initial response", slog.Any("error", err))
 	}
 
 	slog.Info("Waiting for updates...")
 
-	for range p.Heartbeat {
-		err = p.UpdateDevices()
+	for range p.heartbeat {
+		devs, err = p.UpdateDevices()
 		if err != nil {
 			slog.Error("Error reading devices", slog.Any("error", err))
 			continue
 		}
 
-		devs := p.GetDevices()
-		slog.Info("Devices updated", "len", len(devs))
+		slog.Info("Devices updated", slog.Int("len", len(devs)))
 
 		err = s.Send(&pluginapi.ListAndWatchResponse{Devices: devs})
 		if err != nil {
@@ -100,11 +99,11 @@ func (p *Plugin) ListAndWatch(e *pluginapi.Empty, s pluginapi.DevicePlugin_ListA
 	return nil
 }
 
-func (p *Plugin) GetPreferredAllocation(context.Context, *pluginapi.PreferredAllocationRequest) (*pluginapi.PreferredAllocationResponse, error) {
+func (p *plugin) GetPreferredAllocation(context.Context, *pluginapi.PreferredAllocationRequest) (*pluginapi.PreferredAllocationResponse, error) {
 	return &pluginapi.PreferredAllocationResponse{}, nil
 }
 
-func (p *Plugin) Allocate(ctx context.Context, r *pluginapi.AllocateRequest) (*pluginapi.AllocateResponse, error) {
+func (p *plugin) Allocate(ctx context.Context, r *pluginapi.AllocateRequest) (*pluginapi.AllocateResponse, error) {
 	var response pluginapi.AllocateResponse
 	var car pluginapi.ContainerAllocateResponse
 	var dev *pluginapi.DeviceSpec
@@ -119,61 +118,12 @@ func (p *Plugin) Allocate(ctx context.Context, r *pluginapi.AllocateRequest) (*p
 		for _, id := range req.DevicesIDs {
 			slog.Info("Allocating device", slog.String("ID", id))
 
-			dev.HostPath = p.RtlSdrs[id].DevicePath()
-			dev.ContainerPath = p.RtlSdrs[id].DevicePath()
+			dev.HostPath = p.devices[id].DevicePath()
+			dev.ContainerPath = p.devices[id].DevicePath()
 		}
 
 		response.ContainerResponses = append(response.ContainerResponses, &car)
 	}
 
 	return &response, nil
 }
-
-type RtlSdrDev struct {
-	*gousb.Device
-
-	SerialNumber string
-	Connected    bool
-}
-
-func (r RtlSdrDev) DevicePath() string {
-	return fmt.Sprintf("/dev/bus/usb/%03d/%03d", r.Device.Desc.Bus, r.Device.Desc.Address)
-}
-
-func NewRtlSdrDev(dev *gousb.Device) *RtlSdrDev {
-	serial, _ := dev.SerialNumber()
-
-	return &RtlSdrDev{
-		Device:       dev,
-		SerialNumber: serial,
-		Connected:    true,
-	}
-}
-
-func ListDevices() ([]*RtlSdrDev, error) {
-	ctx := gousb.NewContext()
-	defer func() {
-		_ = ctx.Close()
-	}()
-
-	devs, err := ctx.OpenDevices(func(desc *gousb.DeviceDesc) bool {
-		return desc.Vendor == 0x0bda
-	})
-	for i := range devs {
-		defer func(i int) {
-			_ = devs[i].Close()
-		}(i)
-	}
-
-	if err != nil {
-		slog.Info("Error open device", slog.Int("len", len(devs)), slog.Any("error", err))
-		return nil, err
-	}
-
-	devices := make([]*RtlSdrDev, len(devs))
-	for i := range devs {
-		devices[i] = NewRtlSdrDev(devs[i])
-	}
-
-	return devices, nil
-}

device-plugin/rtl-sdr/usb.go

@@ -0,0 +1,115 @@
+package rtlsdr
+
+import (
+	"bytes"
+	"fmt"
+	"io/fs"
+	"log/slog"
+	"path/filepath"
+	"slices"
+	"strconv"
+)
+
+type UsbDevice struct {
+	Serial    string
+	VendorID  string
+	ProductID string
+	Bus       int
+	Dev       int
+}
+
+// supportedProducts is a map of supported products per vendor ID.
+var supportedProducts = map[string][]string{
+	// 0bda = RealTek, 2838 = RTL2838UHIDIR
+	"0bda": {"2838"},
+}
+
+func (d UsbDevice) DevicePath() string {
+	return fmt.Sprintf("/dev/bus/usb/%03d/%03d", d.Bus, d.Dev)
+}
+
+func ListUsbDevices(fsys fs.FS) ([]*UsbDevice, error) {
+	const devicesPath = "sys/bus/usb/devices"
+
+	entries, err := fs.ReadDir(fsys, devicesPath)
+	if err != nil {
+		return nil, fmt.Errorf("failed reading '%s': %w", devicesPath, err)
+	}
+
+	devices := []*UsbDevice{}
+	for i := range entries {
+		// Check if it is a directory or symlink
+		if !entries[i].IsDir() && entries[i].Type()&fs.ModeSymlink == 0 {
+			slog.Info("Skipping", slog.String("name", entries[i].Name()))
+			continue
+		}
+
+		path := filepath.Join(devicesPath, entries[i].Name())
+		dev, err := ReadUsbDevice(fsys, path)
+		if err != nil {
+			slog.Debug("failed reading USB device", slog.String("path", path), slog.Any("error", err))
+			continue
+		}
+
+		if !isSupportedProduct(dev.VendorID, dev.ProductID) {
+			continue
+		}
+
+		devices = append(devices, dev)
+	}
+
+	return devices, nil
+}
+
+func isSupportedProduct(vendorID, productID string) bool {
+	if prods, ok := supportedProducts[vendorID]; ok {
+		return slices.Contains(prods, productID)
+	}
+
+	return false
+}
+
+func ReadUsbDevice(fsys fs.FS, dir string) (*UsbDevice, error) {
+	vendorID, err := fs.ReadFile(fsys, filepath.Join(dir, "idVendor"))
+	if err != nil {
+		return nil, fmt.Errorf("failed reading '%s/idVendor': %w", dir, err)
+	}
+
+	productID, err := fs.ReadFile(fsys, filepath.Join(dir, "idProduct"))
+	if err != nil {
+		return nil, fmt.Errorf("failed reading '%s/idProduct': %w", dir, err)
+	}
+
+	busnum, err := fs.ReadFile(fsys, filepath.Join(dir, "busnum"))
+	if err != nil {
+		return nil, fmt.Errorf("failed reading '%s/busnum': %w", dir, err)
+	}
+
+	bus, err := strconv.Atoi(string(bytes.TrimSuffix(busnum, []byte("\n"))))
+	if err != nil {
+		return nil, fmt.Errorf("failed converting '%s' to int: %w", busnum, err)
+	}
+
+	devnum, err := fs.ReadFile(fsys, filepath.Join(dir, "devnum"))
+	if err != nil {
+		return nil, fmt.Errorf("failed reading '%s/devnum': %w", dir, err)
+	}
+
+	dev, err := strconv.Atoi(string(bytes.TrimSuffix(devnum, []byte("\n"))))
+	if err != nil {
+		return nil, fmt.Errorf("failed converting '%s' to int: %w", devnum, err)
+	}
+
+	serial, err := fs.ReadFile(fsys, filepath.Join(dir, "serial"))
+	if err != nil {
+		return nil, fmt.Errorf("failed reading '%s/serial': %w", dir, err)
+	}
+
+	return &UsbDevice{
+		VendorID:  string(bytes.TrimSuffix(vendorID, []byte("\n"))),
+		ProductID: string(bytes.TrimSuffix(productID, []byte("\n"))),
+		Bus:       bus,
+		Dev:       dev,
+		Serial:    string(bytes.TrimSuffix(serial, []byte("\n"))),
+	}, nil
+}