kvm/internal/usbgadget/udc.go

127 lines
3.0 KiB
Go

package usbgadget
import (
"context"
"fmt"
"os"
"path"
"strings"
"time"
)
func getUdcs() []string {
var udcs []string
files, err := os.ReadDir("/sys/devices/platform/usbdrd")
if err != nil {
return nil
}
for _, file := range files {
if !file.IsDir() || !strings.HasSuffix(file.Name(), ".usb") {
continue
}
udcs = append(udcs, file.Name())
}
return udcs
}
func rebindUsb(udc string, ignoreUnbindError bool) error {
return rebindUsbWithTimeout(udc, ignoreUnbindError, 10*time.Second)
}
func rebindUsbWithTimeout(udc string, ignoreUnbindError bool, timeout time.Duration) error {
ctx, cancel := context.WithTimeout(context.Background(), timeout)
defer cancel()
// Unbind with timeout
err := writeFileWithTimeout(ctx, path.Join(dwc3Path, "unbind"), []byte(udc), 0644)
if err != nil && !ignoreUnbindError {
return fmt.Errorf("failed to unbind UDC: %w", err)
}
// Small delay to allow unbind to complete
time.Sleep(100 * time.Millisecond)
// Bind with timeout
err = writeFileWithTimeout(ctx, path.Join(dwc3Path, "bind"), []byte(udc), 0644)
if err != nil {
return fmt.Errorf("failed to bind UDC: %w", err)
}
return nil
}
func writeFileWithTimeout(ctx context.Context, filename string, data []byte, perm os.FileMode) error {
done := make(chan error, 1)
go func() {
done <- os.WriteFile(filename, data, perm)
}()
select {
case err := <-done:
return err
case <-ctx.Done():
return fmt.Errorf("write operation timed out: %w", ctx.Err())
}
}
func (u *UsbGadget) rebindUsb(ignoreUnbindError bool) error {
u.log.Info().Str("udc", u.udc).Msg("rebinding USB gadget to UDC")
return rebindUsb(u.udc, ignoreUnbindError)
}
// RebindUsb rebinds the USB gadget to the UDC.
func (u *UsbGadget) RebindUsb(ignoreUnbindError bool) error {
u.configLock.Lock()
defer u.configLock.Unlock()
return u.rebindUsb(ignoreUnbindError)
}
// GetUsbState returns the current state of the USB gadget
func (u *UsbGadget) GetUsbState() (state string) {
stateFile := path.Join("/sys/class/udc", u.udc, "state")
stateBytes, err := os.ReadFile(stateFile)
if err != nil {
if os.IsNotExist(err) {
return "not attached"
} else {
u.log.Trace().Err(err).Msg("failed to read usb state")
}
return "unknown"
}
return strings.TrimSpace(string(stateBytes))
}
// IsUDCBound checks if the UDC state is bound.
func (u *UsbGadget) IsUDCBound() (bool, error) {
udcFilePath := path.Join(dwc3Path, u.udc)
_, err := os.Stat(udcFilePath)
if err != nil {
if os.IsNotExist(err) {
return false, nil
}
return false, fmt.Errorf("error checking USB emulation state: %w", err)
}
return true, nil
}
// BindUDC binds the gadget to the UDC.
func (u *UsbGadget) BindUDC() error {
err := os.WriteFile(path.Join(dwc3Path, "bind"), []byte(u.udc), 0644)
if err != nil {
return fmt.Errorf("error binding UDC: %w", err)
}
return nil
}
// UnbindUDC unbinds the gadget from the UDC.
func (u *UsbGadget) UnbindUDC() error {
err := os.WriteFile(path.Join(dwc3Path, "unbind"), []byte(u.udc), 0644)
if err != nil {
return fmt.Errorf("error unbinding UDC: %w", err)
}
return nil
}