Maint: do not mock os functions

- Use filepaths with /tmp for tests instead
- Only mock functions where filepath can't be specified such as user.Lookup

cmd/gluetun/main.go

@@ -6,7 +6,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
-	nativeos "os"
+	"os"
 	"os/signal"
 	"strconv"
 	"strings"
@@ -33,8 +33,6 @@ import (
 	"github.com/qdm12/gluetun/internal/updater"
 	versionpkg "github.com/qdm12/gluetun/internal/version"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
-	"github.com/qdm12/golibs/os/user"
 	"github.com/qdm12/golibs/params"
 	"github.com/qdm12/goshutdown"
 	"github.com/qdm12/gosplash"
@@ -61,21 +59,19 @@ func main() {
 	}
 
 	ctx := context.Background()
-	ctx, stop := signal.NotifyContext(ctx, syscall.SIGINT, syscall.SIGTERM, nativeos.Interrupt)
+	ctx, stop := signal.NotifyContext(ctx, syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
 	ctx, cancel := context.WithCancel(ctx)
 
 	logger := logging.NewParent(logging.Settings{})
 
-	args := nativeos.Args
+	args := os.Args
-	os := os.New()
-	osUser := user.New()
 	unix := unix.New()
 	cli := cli.New()
 	env := params.NewEnv()
 
 	errorCh := make(chan error)
 	go func() {
-		errorCh <- _main(ctx, buildInfo, args, logger, env, os, osUser, unix, cli)
+		errorCh <- _main(ctx, buildInfo, args, logger, env, unix, cli)
 	}()
 
 	select {
@@ -86,7 +82,7 @@ func main() {
 		stop()
 		close(errorCh)
 		if err == nil { // expected exit such as healthcheck
-			nativeos.Exit(0)
+			os.Exit(0)
 		}
 		logger.Error(err)
 		cancel()
@@ -104,7 +100,7 @@ func main() {
 		logger.Warn("Shutdown timed out")
 	}
 
-	nativeos.Exit(1)
+	os.Exit(1)
 }
 
 var (
@@ -113,18 +109,18 @@ var (
 
 //nolint:gocognit,gocyclo
 func _main(ctx context.Context, buildInfo models.BuildInformation,
-	args []string, logger logging.ParentLogger, env params.Env, os os.OS,
+	args []string, logger logging.ParentLogger, env params.Env,
-	osUser user.OSUser, unix unix.Unix, cli cli.CLI) error {
+	unix unix.Unix, cli cli.CLI) error {
 	if len(args) > 1 { // cli operation
 		switch args[1] {
 		case "healthcheck":
-			return cli.HealthCheck(ctx, env, os, logger)
+			return cli.HealthCheck(ctx, env, logger)
 		case "clientkey":
-			return cli.ClientKey(args[2:], os.OpenFile)
+			return cli.ClientKey(args[2:])
 		case "openvpnconfig":
-			return cli.OpenvpnConfig(os, logger)
+			return cli.OpenvpnConfig(logger)
 		case "update":
-			return cli.Update(ctx, args[2:], os, logger)
+			return cli.Update(ctx, args[2:], logger)
 		default:
 			return fmt.Errorf("%w: %s", errCommandUnknown, args[1])
 		}
@@ -133,19 +129,19 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	const clientTimeout = 15 * time.Second
 	httpClient := &http.Client{Timeout: clientTimeout}
 	// Create configurators
-	alpineConf := alpine.NewConfigurator(os.OpenFile, osUser)
+	alpineConf := alpine.NewConfigurator()
 	ovpnConf := openvpn.NewConfigurator(
 		logger.NewChild(logging.Settings{Prefix: "openvpn configurator: "}),
-		os, unix)
+		unix)
 	dnsCrypto := dnscrypto.New(httpClient, "", "")
 	const cacertsPath = "/etc/ssl/certs/ca-certificates.crt"
-	dnsConf := unbound.NewConfigurator(nil, os.OpenFile, dnsCrypto,
+	dnsConf := unbound.NewConfigurator(nil, dnsCrypto,
 		"/etc/unbound", "/usr/sbin/unbound", cacertsPath)
 	routingConf := routing.NewRouting(
 		logger.NewChild(logging.Settings{Prefix: "routing: "}))
 	firewallConf := firewall.NewConfigurator(
 		logger.NewChild(logging.Settings{Prefix: "firewall: "}),
-		routingConf, os.OpenFile)
+		routingConf)
 
 	announcementExp, err := time.Parse(time.RFC3339, "2021-07-22T00:00:00Z")
 	if err != nil {
@@ -179,7 +175,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	}
 
 	var allSettings configuration.Settings
-	err = allSettings.Read(env, os,
+	err = allSettings.Read(env,
 		logger.NewChild(logging.Settings{Prefix: "configuration: "}))
 	if err != nil {
 		return err
@@ -196,7 +192,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	// TODO run this in a loop or in openvpn to reload from file without restarting
 	storage := storage.New(
 		logger.NewChild(logging.Settings{Prefix: "storage: "}),
-		os, constants.ServersData)
+		constants.ServersData)
 	allServers, err := storage.SyncServers(constants.GetAllServers())
 	if err != nil {
 		return err
@@ -314,7 +310,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	otherGroupHandler := goshutdown.NewGroupHandler("other", defaultGroupSettings)
 
 	openvpnLooper := openvpn.NewLooper(allSettings.OpenVPN, nonRootUsername, puid, pgid, allServers,
-		ovpnConf, firewallConf, routingConf, logger, httpClient, os.OpenFile, tunnelReadyCh)
+		ovpnConf, firewallConf, routingConf, logger, httpClient, tunnelReadyCh)
 	openvpnHandler, openvpnCtx, openvpnDone := goshutdown.NewGoRoutineHandler(
 		"openvpn", goshutdown.GoRoutineSettings{Timeout: time.Second})
 	// wait for restartOpenvpn
@@ -331,7 +327,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 
 	unboundLogger := logger.NewChild(logging.Settings{Prefix: "dns over tls: "})
 	unboundLooper := dns.NewLooper(dnsConf, allSettings.DNS, httpClient,
-		unboundLogger, os.OpenFile)
+		unboundLogger)
 	dnsHandler, dnsCtx, dnsDone := goshutdown.NewGoRoutineHandler(
 		"unbound", defaultGoRoutineSettings)
 	// wait for unboundLooper.Restart or its ticker launched with RunRestartTicker
@@ -340,7 +336,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 
 	publicIPLooper := publicip.NewLooper(httpClient,
 		logger.NewChild(logging.Settings{Prefix: "ip getter: "}),
-		allSettings.PublicIP, puid, pgid, os)
+		allSettings.PublicIP, puid, pgid)
 	pubIPHandler, pubIPCtx, pubIPDone := goshutdown.NewGoRoutineHandler(
 		"public IP", defaultGoRoutineSettings)
 	go publicIPLooper.Run(pubIPCtx, pubIPDone)

go.mod

@@ -5,7 +5,7 @@ go 1.16
 require (
 	github.com/fatih/color v1.12.0
 	github.com/golang/mock v1.6.0
-	github.com/qdm12/dns v1.9.0
+	github.com/qdm12/dns v1.10.0
 	github.com/qdm12/golibs v0.0.0-20210721223530-ec1d3fe6dc99
 	github.com/qdm12/goshutdown v0.1.0
 	github.com/qdm12/gosplash v0.1.0

go.sum

@@ -63,8 +63,8 @@ github.com/phayes/permbits v0.0.0-20190612203442-39d7c581d2ee/go.mod h1:3uODdxMg
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/qdm12/dns v1.9.0 h1:p4g/BfbpQ+gJRpQdklDAnybkjds+OuenF0wEGoZ8/AI=
+github.com/qdm12/dns v1.10.0 h1:WX5QQ5+2h34xfhfxJTmvyURbs9XE4qNrEGtyNeq38Bw=
-github.com/qdm12/dns v1.9.0/go.mod h1:fqZoDf3VzddnKBMNI/OzZUp5H4dO0VBw1fp4qPkolOg=
+github.com/qdm12/dns v1.10.0/go.mod h1:fqZoDf3VzddnKBMNI/OzZUp5H4dO0VBw1fp4qPkolOg=
 github.com/qdm12/golibs v0.0.0-20210603202746-e5494e9c2ebb/go.mod h1:15RBzkun0i8XB7ADIoLJWp9ITRgsz3LroEI2FiOXLRg=
 github.com/qdm12/golibs v0.0.0-20210716185557-66793f4ddd80/go.mod h1:15RBzkun0i8XB7ADIoLJWp9ITRgsz3LroEI2FiOXLRg=
 github.com/qdm12/golibs v0.0.0-20210721223530-ec1d3fe6dc99 h1:2OKHAR0SK8BtTtWCRNoSn58eh+iVDA3Cwq4i2CnD3i4=

internal/alpine/alpine.go

@@ -3,9 +3,7 @@ package alpine
 
 import (
 	"context"
-
+	"os/user"
-	"github.com/qdm12/golibs/os"
-	"github.com/qdm12/golibs/os/user"
 )
 
 type Configurator interface {
@@ -14,13 +12,17 @@ type Configurator interface {
 }
 
 type configurator struct {
-	openFile os.OpenFileFunc
+	alpineReleasePath string
-	osUser   user.OSUser
+	passwdPath        string
+	lookupID          func(uid string) (*user.User, error)
+	lookup            func(username string) (*user.User, error)
 }
 
-func NewConfigurator(openFile os.OpenFileFunc, osUser user.OSUser) Configurator {
+func NewConfigurator() Configurator {
 	return &configurator{
-		openFile: openFile,
+		alpineReleasePath: "/etc/alpine-release",
-		osUser:   osUser,
+		passwdPath:        "/etc/passwd",
+		lookupID:          user.LookupId,
+		lookup:            user.Lookup,
 	}
 }

internal/alpine/users.go

@@ -15,7 +15,7 @@ var (
 // CreateUser creates a user in Alpine with the given UID.
 func (c *configurator) CreateUser(username string, uid int) (createdUsername string, err error) {
 	UIDStr := strconv.Itoa(uid)
-	u, err := c.osUser.LookupID(UIDStr)
+	u, err := c.lookupID(UIDStr)
 	_, unknownUID := err.(user.UnknownUserIdError)
 	if err != nil && !unknownUID {
 		return "", err
@@ -28,7 +28,7 @@ func (c *configurator) CreateUser(username string, uid int) (createdUsername str
 		return u.Username, nil
 	}
 
-	u, err = c.osUser.Lookup(username)
+	u, err = c.lookup(username)
 	_, unknownUsername := err.(user.UnknownUserError)
 	if err != nil && !unknownUsername {
 		return "", err
@@ -39,7 +39,7 @@ func (c *configurator) CreateUser(username string, uid int) (createdUsername str
 			ErrUserAlreadyExists, username, u.Uid, uid)
 	}
 
-	file, err := c.openFile("/etc/passwd", os.O_APPEND|os.O_WRONLY, 0644)
+	file, err := os.OpenFile(c.passwdPath, os.O_APPEND|os.O_WRONLY, 0644)
 	if err != nil {
 		return "", err
 	}

internal/alpine/version.go

@@ -8,7 +8,7 @@ import (
 )
 
 func (c *configurator) Version(ctx context.Context) (version string, err error) {
-	file, err := c.openFile("/etc/alpine-release", os.O_RDONLY, 0)
+	file, err := os.OpenFile(c.alpineReleasePath, os.O_RDONLY, 0)
 	if err != nil {
 		return "", err
 	}

internal/cli/cli.go

@@ -5,19 +5,22 @@ import (
 	"context"
 
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 	"github.com/qdm12/golibs/params"
 )
 
 type CLI interface {
-	ClientKey(args []string, openFile os.OpenFileFunc) error
+	ClientKey(args []string) error
-	HealthCheck(ctx context.Context, env params.Env, os os.OS, logger logging.Logger) error
+	HealthCheck(ctx context.Context, env params.Env, logger logging.Logger) error
-	OpenvpnConfig(os os.OS, logger logging.Logger) error
+	OpenvpnConfig(logger logging.Logger) error
-	Update(ctx context.Context, args []string, os os.OS, logger logging.Logger) error
+	Update(ctx context.Context, args []string, logger logging.Logger) error
 }
 
-type cli struct{}
+type cli struct {
+	repoServersPath string
+}
 
 func New() CLI {
-	return &cli{}
+	return &cli{
+		repoServersPath: "./internal/constants/servers.json",
+	}
 }

internal/cli/clientkey.go

@@ -4,19 +4,19 @@ import (
 	"flag"
 	"fmt"
 	"io"
+	"os"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/constants"
-	"github.com/qdm12/golibs/os"
 )
 
-func (c *cli) ClientKey(args []string, openFile os.OpenFileFunc) error {
+func (c *cli) ClientKey(args []string) error {
 	flagSet := flag.NewFlagSet("clientkey", flag.ExitOnError)
 	filepath := flagSet.String("path", constants.ClientKey, "file path to the client.key file")
 	if err := flagSet.Parse(args); err != nil {
 		return err
 	}
-	file, err := openFile(*filepath, os.O_RDONLY, 0)
+	file, err := os.OpenFile(*filepath, os.O_RDONLY, 0)
 	if err != nil {
 		return err
 	}

internal/cli/healthcheck.go

@@ -9,15 +9,14 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration"
 	"github.com/qdm12/gluetun/internal/healthcheck"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 	"github.com/qdm12/golibs/params"
 )
 
 func (c *cli) HealthCheck(ctx context.Context, env params.Env,
-	os os.OS, logger logging.Logger) error {
+	logger logging.Logger) error {
 	// Extract the health server port from the configuration.
 	config := configuration.Health{}
-	err := config.Read(env, os, logger)
+	err := config.Read(env, logger)
 	if err != nil {
 		return err
 	}

internal/cli/openvpnconfig.go

@@ -10,17 +10,16 @@ import (
 	"github.com/qdm12/gluetun/internal/provider"
 	"github.com/qdm12/gluetun/internal/storage"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 	"github.com/qdm12/golibs/params"
 )
 
-func (c *cli) OpenvpnConfig(os os.OS, logger logging.Logger) error {
+func (c *cli) OpenvpnConfig(logger logging.Logger) error {
 	var allSettings configuration.Settings
-	err := allSettings.Read(params.NewEnv(), os, logger)
+	err := allSettings.Read(params.NewEnv(), logger)
 	if err != nil {
 		return err
 	}
-	allServers, err := storage.New(logger, os, constants.ServersData).
+	allServers, err := storage.New(logger, constants.ServersData).
 		SyncServers(constants.GetAllServers())
 	if err != nil {
 		return err

internal/cli/update.go

@@ -7,7 +7,7 @@ import (
 	"flag"
 	"fmt"
 	"net/http"
-	nativeos "os"
+	"os"
 	"time"
 
 	"github.com/qdm12/gluetun/internal/configuration"
@@ -16,7 +16,6 @@ import (
 	"github.com/qdm12/gluetun/internal/storage"
 	"github.com/qdm12/gluetun/internal/updater"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 var (
@@ -26,7 +25,7 @@ var (
 	ErrWriteToFile             = errors.New("cannot write updated information to file")
 )
 
-func (c *cli) Update(ctx context.Context, args []string, os os.OS, logger logging.Logger) error {
+func (c *cli) Update(ctx context.Context, args []string, logger logging.Logger) error {
 	options := configuration.Updater{CLI: true}
 	var endUserMode, maintainerMode, updateAll bool
 	flagSet := flag.NewFlagSet("update", flag.ExitOnError)
@@ -65,7 +64,7 @@ func (c *cli) Update(ctx context.Context, args []string, os os.OS, logger loggin
 
 	const clientTimeout = 10 * time.Second
 	httpClient := &http.Client{Timeout: clientTimeout}
-	storage := storage.New(logger, os, constants.ServersData)
+	storage := storage.New(logger, constants.ServersData)
 	currentServers, err := storage.SyncServers(constants.GetAllServers())
 	if err != nil {
 		return fmt.Errorf("%w: %s", ErrSyncServers, err)
@@ -83,7 +82,7 @@ func (c *cli) Update(ctx context.Context, args []string, os os.OS, logger loggin
 	}
 
 	if maintainerMode {
-		if err := writeToEmbeddedJSON(os, allServers); err != nil {
+		if err := writeToEmbeddedJSON(c.repoServersPath, allServers); err != nil {
 			return fmt.Errorf("%w: %s", ErrWriteToFile, err)
 		}
 	}
@@ -91,10 +90,11 @@ func (c *cli) Update(ctx context.Context, args []string, os os.OS, logger loggin
 	return nil
 }
 
-func writeToEmbeddedJSON(os os.OS, allServers models.AllServers) error {
+func writeToEmbeddedJSON(repoServersPath string,
+	allServers models.AllServers) error {
 	const perms = 0600
-	f, err := os.OpenFile("./internal/constants/servers.json",
+	f, err := os.OpenFile(repoServersPath,
-		nativeos.O_TRUNC|nativeos.O_WRONLY|nativeos.O_CREATE, perms)
+		os.O_TRUNC|os.O_WRONLY|os.O_CREATE, perms)
 	if err != nil {
 		return err
 	}

internal/configuration/health.go

@@ -5,7 +5,6 @@ import (
 	"strings"
 
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 	"github.com/qdm12/golibs/params"
 )
 
@@ -33,8 +32,8 @@ func (settings *Health) lines() (lines []string) {
 }
 
 // Read is to be used for the healthcheck query mode.
-func (settings *Health) Read(env params.Env, os os.OS, logger logging.Logger) (err error) {
+func (settings *Health) Read(env params.Env, logger logging.Logger) (err error) {
-	reader := newReader(env, os, logger)
+	reader := newReader(env, logger)
 	return settings.read(reader)
 }
 

internal/configuration/reader.go

@@ -8,7 +8,6 @@ import (
 	"strings"
 
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 	"github.com/qdm12/golibs/params"
 	"github.com/qdm12/golibs/verification"
 )
@@ -17,15 +16,13 @@ type reader struct {
 	env    params.Env
 	logger logging.Logger
 	regex  verification.Regex
-	os     os.OS
 }
 
-func newReader(env params.Env, os os.OS, logger logging.Logger) reader {
+func newReader(env params.Env, logger logging.Logger) reader {
 	return reader{
 		env:    env,
 		logger: logger,
 		regex:  verification.NewRegex(),
-		os:     os,
 	}
 }
 

internal/configuration/secrets.go

@@ -4,9 +4,9 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 	"strings"
 
-	"github.com/qdm12/golibs/os"
 	"github.com/qdm12/golibs/params"
 )
 
@@ -48,7 +48,7 @@ func (r *reader) getFromEnvOrSecretFile(envKey string, compulsory bool, retroKey
 			ErrGetSecretFilepath, secretFilepathEnvKey, err)
 	}
 
-	file, fileErr := r.os.OpenFile(filepath, os.O_RDONLY, 0)
+	file, fileErr := os.OpenFile(filepath, os.O_RDONLY, 0)
 	if os.IsNotExist(fileErr) {
 		if compulsory {
 			return "", envErr
@@ -85,7 +85,7 @@ func (r *reader) getFromFileOrSecretFile(secretName, filepath string) (
 		return b, fmt.Errorf("environment variable %s: %w: %s", key, ErrGetSecretFilepath, err)
 	}
 
-	b, err = readFromFile(r.os.OpenFile, secretFilepath)
+	b, err = readFromFile(secretFilepath)
 	if err != nil && !os.IsNotExist(err) {
 		return b, fmt.Errorf("%w: %s", ErrReadSecretFile, err)
 	} else if err == nil {
@@ -93,7 +93,7 @@ func (r *reader) getFromFileOrSecretFile(secretName, filepath string) (
 	}
 
 	// Secret file does not exist, try the non secret file
-	b, err = readFromFile(r.os.OpenFile, filepath)
+	b, err = readFromFile(filepath)
 	if err != nil && !os.IsNotExist(err) {
 		return nil, fmt.Errorf("%w: %s", ErrReadSecretFile, err)
 	} else if err == nil {
@@ -102,8 +102,8 @@ func (r *reader) getFromFileOrSecretFile(secretName, filepath string) (
 	return nil, fmt.Errorf("%w: %s and %s", ErrFilesDoNotExist, secretFilepath, filepath)
 }
 
-func readFromFile(openFile os.OpenFileFunc, filepath string) (b []byte, err error) {
+func readFromFile(filepath string) (b []byte, err error) {
-	file, err := openFile(filepath, os.O_RDONLY, 0)
+	file, err := os.Open(filepath)
 	if err != nil {
 		return nil, err
 	}

internal/configuration/settings.go

@@ -6,7 +6,6 @@ import (
 	"strings"
 
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 	"github.com/qdm12/golibs/params"
 )
 
@@ -62,8 +61,8 @@ var (
 
 // Read obtains all configuration options for the program and returns an error as soon
 // as an error is encountered reading them.
-func (settings *Settings) Read(env params.Env, os os.OS, logger logging.Logger) (err error) {
+func (settings *Settings) Read(env params.Env, logger logging.Logger) (err error) {
-	r := newReader(env, os, logger)
+	r := newReader(env, logger)
 
 	settings.VersionInformation, err = r.env.OnOff("VERSION_INFORMATION", params.Default("on"))
 	if err != nil {

internal/dns/loop.go

@@ -16,7 +16,6 @@ import (
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 type Looper interface {
@@ -33,6 +32,7 @@ type Looper interface {
 type looper struct {
 	state        *state
 	conf         unbound.Configurator
+	resolvConf   string
 	blockBuilder blacklist.Builder
 	client       *http.Client
 	logger       logging.Logger
@@ -45,13 +45,12 @@ type looper struct {
 	backoffTime  time.Duration
 	timeNow      func() time.Time
 	timeSince    func(time.Time) time.Duration
-	openFile     os.OpenFileFunc
 }
 
 const defaultBackoffTime = 10 * time.Second
 
 func NewLooper(conf unbound.Configurator, settings configuration.DNS, client *http.Client,
-	logger logging.Logger, openFile os.OpenFileFunc) Looper {
+	logger logging.Logger) Looper {
 	start := make(chan struct{})
 	running := make(chan models.LoopStatus)
 	stop := make(chan struct{})
@@ -63,6 +62,7 @@ func NewLooper(conf unbound.Configurator, settings configuration.DNS, client *ht
 	return &looper{
 		state:        state,
 		conf:         conf,
+		resolvConf:   "/etc/resolv.conf",
 		blockBuilder: blacklist.NewBuilder(client),
 		client:       client,
 		logger:       logger,
@@ -75,7 +75,6 @@ func NewLooper(conf unbound.Configurator, settings configuration.DNS, client *ht
 		backoffTime:  defaultBackoffTime,
 		timeNow:      time.Now,
 		timeSince:    time.Since,
-		openFile:     openFile,
 	}
 }
 
@@ -227,8 +226,8 @@ func (l *looper) setupUnbound(ctx context.Context) (
 
 	// use Unbound
 	nameserver.UseDNSInternally(net.IP{127, 0, 0, 1})
-	err = nameserver.UseDNSSystemWide(l.openFile,
+	err = nameserver.UseDNSSystemWide(l.resolvConf, net.IP{127, 0, 0, 1},
-		net.IP{127, 0, 0, 1}, settings.KeepNameserver)
+		settings.KeepNameserver)
 	if err != nil {
 		l.logger.Error(err)
 	}
@@ -256,8 +255,8 @@ func (l *looper) useUnencryptedDNS(fallback bool) {
 			l.logger.Info("using plaintext DNS at address %s", targetIP)
 		}
 		nameserver.UseDNSInternally(targetIP)
-		if err := nameserver.UseDNSSystemWide(l.openFile,
+		err := nameserver.UseDNSSystemWide(l.resolvConf, targetIP, settings.KeepNameserver)
-			targetIP, settings.KeepNameserver); err != nil {
+		if err != nil {
 			l.logger.Error(err)
 		}
 		return
@@ -271,7 +270,8 @@ func (l *looper) useUnencryptedDNS(fallback bool) {
 		l.logger.Info("using plaintext DNS at address " + targetIP.String())
 	}
 	nameserver.UseDNSInternally(targetIP)
-	if err := nameserver.UseDNSSystemWide(l.openFile, targetIP, settings.KeepNameserver); err != nil {
+	err := nameserver.UseDNSSystemWide(l.resolvConf, targetIP, settings.KeepNameserver)
+	if err != nil {
 		l.logger.Error(err)
 	}
 }

internal/firewall/enable.go

@@ -136,7 +136,7 @@ func (c *configurator) enable(ctx context.Context) (err error) {
 		}
 	}
 
-	if err := c.runUserPostRules(ctx, "/iptables/post-rules.txt", remove); err != nil {
+	if err := c.runUserPostRules(ctx, c.customRulesPath, remove); err != nil {
 		return fmt.Errorf("%w: %s", ErrUserPostRules, err)
 	}
 

internal/firewall/firewall.go

@@ -11,7 +11,6 @@ import (
 	"github.com/qdm12/gluetun/internal/routing"
 	"github.com/qdm12/golibs/command"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 // Configurator allows to change firewall rules and modify network routes.
@@ -32,7 +31,6 @@ type configurator struct { //nolint:maligned
 	commander        command.Commander
 	logger           logging.Logger
 	routing          routing.Routing
-	openFile         os.OpenFileFunc // for custom iptables rules
 	iptablesMutex    sync.Mutex
 	ip6tablesMutex   sync.Mutex
 	debug            bool
@@ -43,7 +41,8 @@ type configurator struct { //nolint:maligned
 	networkInfoMutex sync.Mutex
 
 	// Fixed state
-	ip6Tables bool
+	ip6Tables       bool
+	customRulesPath string
 
 	// State
 	enabled           bool
@@ -54,15 +53,15 @@ type configurator struct { //nolint:maligned
 }
 
 // NewConfigurator creates a new Configurator instance.
-func NewConfigurator(logger logging.Logger, routing routing.Routing, openFile os.OpenFileFunc) Configurator {
+func NewConfigurator(logger logging.Logger, routing routing.Routing) Configurator {
 	commander := command.NewCommander()
 	return &configurator{
 		commander:         commander,
 		logger:            logger,
 		routing:           routing,
-		openFile:          openFile,
 		allowedInputPorts: make(map[uint16]string),
 		ip6Tables:         ip6tablesSupported(context.Background(), commander),
+		customRulesPath:   "/iptables/post-rules.txt",
 	}
 }
 

internal/firewall/iptables.go

@@ -196,7 +196,7 @@ func (c *configurator) acceptInputToPort(ctx context.Context, intf string, port
 }
 
 func (c *configurator) runUserPostRules(ctx context.Context, filepath string, remove bool) error {
-	file, err := c.openFile(filepath, os.O_RDONLY, 0)
+	file, err := os.OpenFile(filepath, os.O_RDONLY, 0)
 	if os.IsNotExist(err) {
 		return nil
 	} else if err != nil {

internal/openvpn/auth.go

@@ -10,14 +10,14 @@ import (
 
 // WriteAuthFile writes the OpenVPN auth file to disk with the right permissions.
 func (c *configurator) WriteAuthFile(user, password string, puid, pgid int) error {
-	file, err := c.os.OpenFile(constants.OpenVPNAuthConf, os.O_RDONLY, 0)
+	file, err := os.Open(c.authFilePath)
 
 	if err != nil && !os.IsNotExist(err) {
 		return err
 	}
 
 	if os.IsNotExist(err) {
-		file, err = c.os.OpenFile(constants.OpenVPNAuthConf, os.O_WRONLY|os.O_CREATE, 0400)
+		file, err = os.OpenFile(c.authFilePath, os.O_WRONLY|os.O_CREATE, 0400)
 		if err != nil {
 			return err
 		}
@@ -49,7 +49,7 @@ func (c *configurator) WriteAuthFile(user, password string, puid, pgid int) erro
 	}
 
 	c.logger.Info("username and password changed in %s", constants.OpenVPNAuthConf)
-	file, err = c.os.OpenFile(constants.OpenVPNAuthConf, os.O_TRUNC|os.O_WRONLY, 0400)
+	file, err = os.OpenFile(c.authFilePath, os.O_TRUNC|os.O_WRONLY, 0400)
 	if err != nil {
 		return err
 	}

internal/openvpn/custom.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"os"
 	"strconv"
 	"strings"
 
@@ -12,14 +13,13 @@ import (
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/utils"
-	"github.com/qdm12/golibs/os"
 )
 
 var errProcessCustomConfig = errors.New("cannot process custom config")
 
 func (l *looper) processCustomConfig(settings configuration.OpenVPN) (
 	lines []string, connection models.OpenVPNConnection, err error) {
-	lines, err = readCustomConfigLines(settings.Config, l.openFile)
+	lines, err = readCustomConfigLines(settings.Config)
 	if err != nil {
 		return nil, connection, fmt.Errorf("%w: %s", errProcessCustomConfig, err)
 	}
@@ -35,9 +35,9 @@ func (l *looper) processCustomConfig(settings configuration.OpenVPN) (
 	return lines, connection, nil
 }
 
-func readCustomConfigLines(filepath string, openFile os.OpenFileFunc) (
+func readCustomConfigLines(filepath string) (
 	lines []string, err error) {
-	file, err := openFile(filepath, os.O_RDONLY, 0)
+	file, err := os.Open(filepath)
 	if err != nil {
 		return nil, err
 	}

internal/openvpn/loop.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"net"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
@@ -14,7 +15,6 @@ import (
 	"github.com/qdm12/gluetun/internal/provider"
 	"github.com/qdm12/gluetun/internal/routing"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 type Looper interface {
@@ -34,9 +34,10 @@ type Looper interface {
 type looper struct {
 	state *state
 	// Fixed parameters
-	username string
+	username       string
-	puid     int
+	puid           int
-	pgid     int
+	pgid           int
+	targetConfPath string
 	// Configurators
 	conf    Configurator
 	fw      firewall.Configurator
@@ -44,7 +45,6 @@ type looper struct {
 	// Other objects
 	logger, pfLogger logging.Logger
 	client           *http.Client
-	openFile         os.OpenFileFunc
 	tunnelReady      chan<- struct{}
 	// Internal channels and values
 	stop               <-chan struct{}
@@ -64,7 +64,7 @@ const (
 func NewLooper(settings configuration.OpenVPN,
 	username string, puid, pgid int, allServers models.AllServers,
 	conf Configurator, fw firewall.Configurator, routing routing.Routing,
-	logger logging.ParentLogger, client *http.Client, openFile os.OpenFileFunc,
+	logger logging.ParentLogger, client *http.Client,
 	tunnelReady chan<- struct{}) Looper {
 	start := make(chan struct{})
 	running := make(chan models.LoopStatus)
@@ -79,13 +79,13 @@ func NewLooper(settings configuration.OpenVPN,
 		username:           username,
 		puid:               puid,
 		pgid:               pgid,
+		targetConfPath:     constants.OpenVPNConf,
 		conf:               conf,
 		fw:                 fw,
 		routing:            routing,
 		logger:             logger.NewChild(logging.Settings{Prefix: "openvpn: "}),
 		pfLogger:           logger.NewChild(logging.Settings{Prefix: "port forwarding: "}),
 		client:             client,
-		openFile:           openFile,
 		tunnelReady:        tunnelReady,
 		start:              start,
 		running:            running,
@@ -145,7 +145,7 @@ func (l *looper) Run(ctx context.Context, done chan<- struct{}) {
 			}
 		}
 
-		if err := writeOpenvpnConf(lines, l.openFile); err != nil {
+		if err := l.writeOpenvpnConf(lines); err != nil {
 			l.signalOrSetStatus(constants.Crashed)
 			l.logAndWait(ctx, err)
 			continue
@@ -279,13 +279,12 @@ func (l *looper) portForward(ctx context.Context,
 		defer l.state.settingsMu.RUnlock()
 		return settings.Provider.PortForwarding.Filepath
 	}
-	providerConf.PortForward(ctx,
+	providerConf.PortForward(ctx, client, l.pfLogger,
-		client, l.openFile, l.pfLogger,
 		gateway, l.fw, syncState)
 }
 
-func writeOpenvpnConf(lines []string, openFile os.OpenFileFunc) error {
+func (l *looper) writeOpenvpnConf(lines []string) error {
-	file, err := openFile(constants.OpenVPNConf, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+	file, err := os.OpenFile(l.targetConfPath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
 	if err != nil {
 		return err
 	}

internal/openvpn/openvpn.go

@@ -5,10 +5,10 @@ package openvpn
 import (
 	"context"
 
+	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/unix"
 	"github.com/qdm12/golibs/command"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 type Configurator interface {
@@ -22,17 +22,19 @@ type Configurator interface {
 }
 
 type configurator struct {
-	logger    logging.Logger
+	logger       logging.Logger
-	commander command.Commander
+	commander    command.Commander
-	os        os.OS
+	unix         unix.Unix
-	unix      unix.Unix
+	authFilePath string
+	tunDevPath   string
 }
 
-func NewConfigurator(logger logging.Logger, os os.OS, unix unix.Unix) Configurator {
+func NewConfigurator(logger logging.Logger, unix unix.Unix) Configurator {
 	return &configurator{
-		logger:    logger,
+		logger:       logger,
-		commander: command.NewCommander(),
+		commander:    command.NewCommander(),
-		os:        os,
+		unix:         unix,
-		unix:      unix,
+		authFilePath: constants.OpenVPNAuthConf,
+		tunDevPath:   constants.TunnelDevice,
 	}
 }

internal/openvpn/tun.go

@@ -3,15 +3,15 @@ package openvpn
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 
-	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/unix"
 )
 
 // CheckTUN checks the tunnel device is present and accessible.
 func (c *configurator) CheckTUN() error {
-	c.logger.Info("checking for device %s", constants.TunnelDevice)
+	c.logger.Info("checking for device " + c.tunDevPath)
-	f, err := c.os.OpenFile(constants.TunnelDevice, os.O_RDWR, 0)
+	f, err := os.OpenFile(c.tunDevPath, os.O_RDWR, 0)
 	if err != nil {
 		return fmt.Errorf("TUN device is not available: %w", err)
 	}
@@ -22,8 +22,10 @@ func (c *configurator) CheckTUN() error {
 }
 
 func (c *configurator) CreateTUN() error {
-	c.logger.Info("creating %s", constants.TunnelDevice)
+	c.logger.Info("creating " + c.tunDevPath)
-	if err := c.os.MkdirAll("/dev/net", 0751); err != nil { //nolint:gomnd
+
+	parentDir := filepath.Dir(c.tunDevPath)
+	if err := os.MkdirAll(parentDir, 0751); err != nil { //nolint:gomnd
 		return err
 	}
 
@@ -32,17 +34,13 @@ func (c *configurator) CreateTUN() error {
 		minor = 200
 	)
 	dev := c.unix.Mkdev(major, minor)
-	if err := c.unix.Mknod(constants.TunnelDevice, unix.S_IFCHR, int(dev)); err != nil {
+	if err := c.unix.Mknod(c.tunDevPath, unix.S_IFCHR, int(dev)); err != nil {
 		return err
 	}
 
-	file, err := c.os.OpenFile(constants.TunnelDevice, os.O_WRONLY, 0666) //nolint:gomnd
-	if err != nil {
-		return err
-	}
 	const readWriteAllPerms os.FileMode = 0666
-	if err := file.Chmod(readWriteAllPerms); err != nil {
+	file, err := os.OpenFile(c.tunDevPath, os.O_WRONLY, readWriteAllPerms)
-		_ = file.Close()
+	if err != nil {
 		return err
 	}
 

internal/provider/cyberghost/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (c *Cyberghost) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Cyberghost")
 }

internal/provider/fastestvpn/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (f *Fastestvpn) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for FastestVPN")
 }

internal/provider/hidemyass/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (f *HideMyAss) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for HideMyAss")
 }

internal/provider/ipvanish/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (i *Ipvanish) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Ipvanish")
 }

internal/provider/ivpn/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (i *Ivpn) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Ivpn")
 }

internal/provider/mullvad/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (m *Mullvad) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding logic is not needed for Mullvad")
 }

internal/provider/nordvpn/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (n *Nordvpn) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for NordVPN")
 }

internal/provider/privado/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (p *Privado) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Privado")
 }

internal/provider/privateinternetaccess/portforward.go

@@ -10,6 +10,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"strconv"
 	"strings"
 	"time"
@@ -18,7 +19,6 @@ import (
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/gluetun/internal/format"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 var (
@@ -28,7 +28,7 @@ var (
 // PortForward obtains a VPN server side port forwarded from PIA.
 //nolint:gocognit
 func (p *PIA) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, logger logging.Logger, gateway net.IP, fw firewall.Configurator,
+	logger logging.Logger, gateway net.IP, fw firewall.Configurator,
 	syncState func(port uint16) (pfFilepath string)) {
 	commonName := p.activeServer.ServerName
 	if !p.activeServer.PortForward {
@@ -47,7 +47,7 @@ func (p *PIA) PortForward(ctx context.Context, client *http.Client,
 		return
 	}
 
-	data, err := readPIAPortForwardData(openFile)
+	data, err := readPIAPortForwardData(p.portForwardPath)
 	if err != nil {
 		logger.Error(err)
 	}
@@ -67,7 +67,8 @@ func (p *PIA) PortForward(ctx context.Context, client *http.Client,
 
 	if !dataFound || expired {
 		tryUntilSuccessful(ctx, logger, func() error {
-			data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, gateway, openFile)
+			data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, gateway,
+				p.portForwardPath, p.authFilePath)
 			return err
 		})
 		if ctx.Err() != nil {
@@ -91,7 +92,7 @@ func (p *PIA) PortForward(ctx context.Context, client *http.Client,
 
 	filepath := syncState(data.Port)
 	logger.Info("Writing port to " + filepath)
-	if err := writePortForwardedToFile(openFile, filepath, data.Port); err != nil {
+	if err := writePortForwardedToFile(filepath, data.Port); err != nil {
 		logger.Error(err)
 	}
 
@@ -128,7 +129,8 @@ func (p *PIA) PortForward(ctx context.Context, client *http.Client,
 				data.Expiration.Format(time.RFC1123) + ", getting another one")
 			oldPort := data.Port
 			for {
-				data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, gateway, openFile)
+				data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, gateway,
+					p.portForwardPath, p.authFilePath)
 				if err != nil {
 					logger.Error(err)
 					continue
@@ -146,7 +148,7 @@ func (p *PIA) PortForward(ctx context.Context, client *http.Client,
 			}
 			filepath := syncState(data.Port)
 			logger.Info("Writing port to " + filepath)
-			if err := writePortForwardedToFile(openFile, filepath, data.Port); err != nil {
+			if err := writePortForwardedToFile(filepath, data.Port); err != nil {
 				logger.Error("Cannot write port forward data to file: " + err.Error())
 			}
 			if err := bindPort(ctx, privateIPClient, gateway, data); err != nil {
@@ -168,8 +170,8 @@ var (
 )
 
 func refreshPIAPortForwardData(ctx context.Context, client, privateIPClient *http.Client,
-	gateway net.IP, openFile os.OpenFileFunc) (data piaPortForwardData, err error) {
+	gateway net.IP, portForwardPath, authFilePath string) (data piaPortForwardData, err error) {
-	data.Token, err = fetchToken(ctx, openFile, client)
+	data.Token, err = fetchToken(ctx, client, authFilePath)
 	if err != nil {
 		return data, fmt.Errorf("%w: %s", ErrFetchToken, err)
 	}
@@ -179,7 +181,7 @@ func refreshPIAPortForwardData(ctx context.Context, client, privateIPClient *htt
 		return data, fmt.Errorf("%w: %s", ErrFetchPortForwarding, err)
 	}
 
-	if err := writePIAPortForwardData(openFile, data); err != nil {
+	if err := writePIAPortForwardData(portForwardPath, data); err != nil {
 		return data, fmt.Errorf("%w: %s", ErrPersistPortForwarding, err)
 	}
 
@@ -199,8 +201,8 @@ type piaPortForwardData struct {
 	Expiration time.Time `json:"expires_at"`
 }
 
-func readPIAPortForwardData(openFile os.OpenFileFunc) (data piaPortForwardData, err error) {
+func readPIAPortForwardData(portForwardPath string) (data piaPortForwardData, err error) {
-	file, err := openFile(constants.PIAPortForward, os.O_RDONLY, 0)
+	file, err := os.Open(portForwardPath)
 	if os.IsNotExist(err) {
 		return data, nil
 	} else if err != nil {
@@ -216,8 +218,8 @@ func readPIAPortForwardData(openFile os.OpenFileFunc) (data piaPortForwardData,
 	return data, file.Close()
 }
 
-func writePIAPortForwardData(openFile os.OpenFileFunc, data piaPortForwardData) (err error) {
+func writePIAPortForwardData(portForwardPath string, data piaPortForwardData) (err error) {
-	file, err := openFile(constants.PIAPortForward, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+	file, err := os.OpenFile(portForwardPath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
 	if err != nil {
 		return err
 	}
@@ -269,9 +271,9 @@ var (
 	errEmptyToken     = errors.New("token received is empty")
 )
 
-func fetchToken(ctx context.Context, openFile os.OpenFileFunc,
+func fetchToken(ctx context.Context, client *http.Client,
-	client *http.Client) (token string, err error) {
+	authFilePath string) (token string, err error) {
-	username, password, err := getOpenvpnCredentials(openFile)
+	username, password, err := getOpenvpnCredentials(authFilePath)
 	if err != nil {
 		return "", fmt.Errorf("%w: %s", errGetCredentials, err)
 	}
@@ -321,8 +323,9 @@ var (
 	errAuthFileMalformed = errors.New("authentication file is malformed")
 )
 
-func getOpenvpnCredentials(openFile os.OpenFileFunc) (username, password string, err error) {
+func getOpenvpnCredentials(authFilePath string) (
-	file, err := openFile(constants.OpenVPNAuthConf, os.O_RDONLY, 0)
+	username, password string, err error) {
+	file, err := os.Open(authFilePath)
 	if err != nil {
 		return "", "", fmt.Errorf("%w: %s", errAuthFileRead, err)
 	}
@@ -460,9 +463,8 @@ func bindPort(ctx context.Context, client *http.Client, gateway net.IP, data pia
 	return nil
 }
 
-func writePortForwardedToFile(openFile os.OpenFileFunc,
+func writePortForwardedToFile(filepath string, port uint16) (err error) {
-	filepath string, port uint16) (err error) {
+	file, err := os.OpenFile(filepath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
-	file, err := openFile(filepath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
 	if err != nil {
 		return err
 	}

internal/provider/privateinternetaccess/provider.go

@@ -4,6 +4,7 @@ import (
 	"math/rand"
 	"time"
 
+	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/models"
 )
 
@@ -12,12 +13,18 @@ type PIA struct {
 	randSource   rand.Source
 	timeNow      func() time.Time
 	activeServer models.PIAServer
+	// Port forwarding
+	portForwardPath string
+	authFilePath    string
 }
 
-func New(servers []models.PIAServer, randSource rand.Source, timeNow func() time.Time) *PIA {
+func New(servers []models.PIAServer, randSource rand.Source,
+	timeNow func() time.Time) *PIA {
 	return &PIA{
-		servers:    servers,
+		servers:         servers,
-		timeNow:    timeNow,
+		timeNow:         timeNow,
-		randSource: randSource,
+		randSource:      randSource,
+		portForwardPath: constants.PIAPortForward,
+		authFilePath:    constants.OpenVPNAuthConf,
 	}
 }

internal/provider/privatevpn/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (p *Privatevpn) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for PrivateVPN")
 }

internal/provider/protonvpn/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (p *Protonvpn) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for ProtonVPN")
 }

internal/provider/provider.go

@@ -30,7 +30,6 @@ import (
 	"github.com/qdm12/gluetun/internal/provider/vyprvpn"
 	"github.com/qdm12/gluetun/internal/provider/windscribe"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 // Provider contains methods to read and modify the openvpn configuration to connect as a client.
@@ -38,7 +37,7 @@ type Provider interface {
 	GetOpenVPNConnection(selection configuration.ServerSelection) (connection models.OpenVPNConnection, err error)
 	BuildConf(connection models.OpenVPNConnection, username string, settings configuration.OpenVPN) (lines []string)
 	PortForward(ctx context.Context, client *http.Client,
-		openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
+		pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
 		syncState func(port uint16) (pfFilepath string))
 }
 

internal/provider/purevpn/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (p *Purevpn) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for PureVPN")
 }

internal/provider/surfshark/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (s *Surfshark) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Surfshark")
 }

internal/provider/torguard/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (t *Torguard) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Torguard")
 }

internal/provider/vpnunlimited/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 func (p *Provider) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for VPN Unlimited")
 }

internal/provider/vyprvpn/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
-func (v *Vyprvpn) PortForward(ctx context.Context, clienv *http.Client,
+func (v *Vyprvpn) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Vyprvpn")
 }

internal/provider/windscribe/portforward.go

@@ -7,11 +7,10 @@ import (
 
 	"github.com/qdm12/gluetun/internal/firewall"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
-func (w *Windscribe) PortForward(ctx context.Context, clienw *http.Client,
+func (w *Windscribe) PortForward(ctx context.Context, client *http.Client,
-	openFile os.OpenFileFunc, pfLogger logging.Logger, gateway net.IP,
+	pfLogger logging.Logger, gateway net.IP, fw firewall.Configurator,
-	fw firewall.Configurator, syncState func(port uint16) (pfFilepath string)) {
+	syncState func(port uint16) (pfFilepath string)) {
 	panic("port forwarding is not supported for Windscribe")
 }

internal/publicip/fs.go

@@ -1,13 +1,11 @@
 package publicip
 
-import "github.com/qdm12/golibs/os"
+import (
+	"os"
+)
 
-func persistPublicIP(openFile os.OpenFileFunc,
+func persistPublicIP(path string, content string, puid, pgid int) error {
-	filepath string, content string, puid, pgid int) error {
+	file, err := os.OpenFile(path, os.O_TRUNC|os.O_WRONLY|os.O_CREATE, 0644)
-	file, err := openFile(
-		filepath,
-		os.O_TRUNC|os.O_WRONLY|os.O_CREATE,
-		0644)
 	if err != nil {
 		return err
 	}

internal/publicip/loop.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"net"
 	"net/http"
+	"os"
 	"sync"
 	"time"
 
@@ -11,7 +12,6 @@ import (
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 type Looper interface {
@@ -31,7 +31,6 @@ type looper struct {
 	getter IPGetter
 	client *http.Client
 	logger logging.Logger
-	os     os.OS
 	// Fixed settings
 	puid int
 	pgid int
@@ -51,8 +50,7 @@ type looper struct {
 const defaultBackoffTime = 5 * time.Second
 
 func NewLooper(client *http.Client, logger logging.Logger,
-	settings configuration.PublicIP, puid, pgid int,
+	settings configuration.PublicIP, puid, pgid int) Looper {
-	os os.OS) Looper {
 	return &looper{
 		state: state{
 			status:   constants.Stopped,
@@ -62,7 +60,6 @@ func NewLooper(client *http.Client, logger logging.Logger,
 		client:       client,
 		getter:       NewIPGetter(client),
 		logger:       logger,
-		os:           os,
 		puid:         puid,
 		pgid:         pgid,
 		start:        make(chan struct{}),
@@ -136,7 +133,7 @@ func (l *looper) Run(ctx context.Context, done chan<- struct{}) {
 				close(errorCh)
 				filepath := l.GetSettings().IPFilepath
 				l.logger.Info("Removing ip file " + filepath)
-				if err := l.os.Remove(filepath); err != nil {
+				if err := os.Remove(filepath); err != nil {
 					l.logger.Error(err)
 				}
 				return
@@ -161,7 +158,7 @@ func (l *looper) Run(ctx context.Context, done chan<- struct{}) {
 				}
 				l.logger.Info(message)
 
-				err = persistPublicIP(l.os.OpenFile, l.state.settings.IPFilepath,
+				err = persistPublicIP(l.state.settings.IPFilepath,
 					ip.String(), l.puid, l.pgid)
 				if err != nil {
 					l.logger.Error(err)

internal/storage/flush.go

@@ -0,0 +1,7 @@
+package storage
+
+import "github.com/qdm12/gluetun/internal/models"
+
+func (s *storage) FlushToFile(allServers models.AllServers) error {
+	return flushToFile(s.filepath, allServers)
+}

internal/storage/storage.go

@@ -4,7 +4,6 @@ package storage
 import (
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/golibs/logging"
-	"github.com/qdm12/golibs/os"
 )
 
 type Storage interface {
@@ -14,14 +13,12 @@ type Storage interface {
 }
 
 type storage struct {
-	os       os.OS
 	logger   logging.Logger
 	filepath string
 }
 
-func New(logger logging.Logger, os os.OS, filepath string) Storage {
+func New(logger logging.Logger, filepath string) Storage {
 	return &storage{
-		os:       os,
 		logger:   logger,
 		filepath: filepath,
 	}

internal/storage/sync.go

@@ -5,11 +5,11 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 	"path/filepath"
 	"reflect"
 
 	"github.com/qdm12/gluetun/internal/models"
-	"github.com/qdm12/golibs/os"
 )
 
 var (
@@ -39,7 +39,7 @@ func countServers(allServers models.AllServers) int {
 
 func (s *storage) SyncServers(hardcodedServers models.AllServers) (
 	allServers models.AllServers, err error) {
-	serversOnFile, err := s.readFromFile(s.filepath)
+	serversOnFile, err := readFromFile(s.filepath)
 	if err != nil {
 		return allServers, fmt.Errorf("%w: %s", ErrCannotReadFile, err)
 	}
@@ -62,14 +62,14 @@ func (s *storage) SyncServers(hardcodedServers models.AllServers) (
 		return allServers, nil
 	}
 
-	if err := s.FlushToFile(allServers); err != nil {
+	if err := flushToFile(s.filepath, allServers); err != nil {
 		return allServers, fmt.Errorf("%w: %s", ErrCannotWriteFile, err)
 	}
 	return allServers, nil
 }
 
-func (s *storage) readFromFile(filepath string) (servers models.AllServers, err error) {
+func readFromFile(filepath string) (servers models.AllServers, err error) {
-	file, err := s.os.OpenFile(filepath, os.O_RDONLY, 0)
+	file, err := os.Open(filepath)
 	if os.IsNotExist(err) {
 		return servers, nil
 	} else if err != nil {
@@ -86,13 +86,13 @@ func (s *storage) readFromFile(filepath string) (servers models.AllServers, err
 	return servers, file.Close()
 }
 
-func (s *storage) FlushToFile(servers models.AllServers) error {
+func flushToFile(path string, servers models.AllServers) error {
-	dirPath := filepath.Dir(s.filepath)
+	dirPath := filepath.Dir(path)
-	if err := s.os.MkdirAll(dirPath, 0644); err != nil {
+	if err := os.MkdirAll(dirPath, 0644); err != nil {
 		return err
 	}
 
-	file, err := s.os.OpenFile(s.filepath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
+	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
 	if err != nil {
 		return err
 	}