Maint: tun package to handle tun device operations

- Moved from openvpn package to tun package
- TUN check verifies Rdev value
- TUN create
- Inject as interface to main function
- Add integration test
- Clearer log message for end users if tun device does not exist
- Remove unix package (unneeded for tests)
- Remove tun file opening at the end of tun file creation
- Do not mock unix.Mkdev (no OS operation)
- Remove Tun operations from OpenVPN configurator

internal/openvpn/openvpn.go

@@ -4,7 +4,6 @@ package openvpn
 
 import (
 	"github.com/qdm12/gluetun/internal/constants"
-	"github.com/qdm12/gluetun/internal/unix"
 	"github.com/qdm12/golibs/command"
 	"github.com/qdm12/golibs/logging"
 )
@@ -12,7 +11,6 @@ import (
 type Configurator interface {
 	VersionGetter
 	AuthWriter
-	TUNCheckCreater
 	Starter
 }
 
@@ -24,18 +22,14 @@ type StarterAuthWriter interface {
 type configurator struct {
 	logger       logging.Logger
 	cmder        command.RunStarter
-	unix         unix.Unix
 	authFilePath string
-	tunDevPath   string
 }
 
-func NewConfigurator(logger logging.Logger, unix unix.Unix,
+func NewConfigurator(logger logging.Logger,
 	cmder command.RunStarter) Configurator {
 	return &configurator{
 		logger:       logger,
 		cmder:        cmder,
-		unix:         unix,
 		authFilePath: constants.OpenVPNAuthConf,
-		tunDevPath:   constants.TunnelDevice,
 	}
 }

internal/openvpn/tun.go

@@ -1,61 +0,0 @@
-package openvpn
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-
-	"github.com/qdm12/gluetun/internal/unix"
-)
-
-type TUNCheckCreater interface {
-	TUNChecker
-	TUNCreater
-}
-
-type TUNChecker interface {
-	CheckTUN() error
-}
-
-// CheckTUN checks the tunnel device is present and accessible.
-func (c *configurator) CheckTUN() error {
-	c.logger.Info("checking for device " + c.tunDevPath)
-	f, err := os.OpenFile(c.tunDevPath, os.O_RDWR, 0)
-	if err != nil {
-		return fmt.Errorf("TUN device is not available: %w", err)
-	}
-	if err := f.Close(); err != nil {
-		c.logger.Warn("Could not close TUN device file: " + err.Error())
-	}
-	return nil
-}
-
-type TUNCreater interface {
-	CreateTUN() error
-}
-
-func (c *configurator) CreateTUN() error {
-	c.logger.Info("creating " + c.tunDevPath)
-
-	parentDir := filepath.Dir(c.tunDevPath)
-	if err := os.MkdirAll(parentDir, 0751); err != nil { //nolint:gomnd
-		return err
-	}
-
-	const (
-		major = 10
-		minor = 200
-	)
-	dev := c.unix.Mkdev(major, minor)
-	if err := c.unix.Mknod(c.tunDevPath, unix.S_IFCHR, int(dev)); err != nil {
-		return err
-	}
-
-	const readWriteAllPerms os.FileMode = 0666
-	file, err := os.OpenFile(c.tunDevPath, os.O_WRONLY, readWriteAllPerms)
-	if err != nil {
-		return err
-	}
-
-	return file.Close()
-}