Root config: Add env config (#6400)

https://github.com/XTLS/Xray-core/pull/6400#issuecomment-4880198100
https://github.com/XTLS/Xray-core/pull/6400#issuecomment-4916892425
https://github.com/XTLS/Xray-core/pull/6400#issuecomment-4929136670

.github/docker/Dockerfile

@@ -37,6 +37,7 @@ RUN echo '{}' >/tmp/usr/local/etc/xray/08_fakedns.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/09_metrics.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/10_observatory.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/11_geodata.json
+RUN echo '{}' >/tmp/usr/local/etc/xray/12_env.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/99_version.json
 
 # Create log files

.github/docker/Dockerfile.usa

@@ -37,6 +37,7 @@ RUN echo '{}' >/tmp/usr/local/etc/xray/08_fakedns.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/09_metrics.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/10_observatory.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/11_geodata.json
+RUN echo '{}' >/tmp/usr/local/etc/xray/12_env.json
 RUN echo '{}' >/tmp/usr/local/etc/xray/99_version.json
 
 # Create log files

common/buf/io.go

@@ -122,7 +122,7 @@ func NewReader(reader io.Reader) Reader {
 	}
 
 	_, isFile := reader.(*os.File)
-	if !isFile && useReadv {
+	if !isFile && useReadV() {
 		if sc, ok := reader.(syscall.Conn); ok {
 			rawConn, err := sc.SyscallConn()
 			if err != nil {

common/buf/readv_reader.go

@@ -5,6 +5,7 @@ package buf
 
 import (
 	"io"
+	"sync/atomic"
 	"syscall"
 
 	"github.com/xtls/xray-core/common/platform"
@@ -143,13 +144,24 @@ func (r *ReadVReader) ReadMultiBuffer() (MultiBuffer, error) {
 	return mb, nil
 }
 
-var useReadv bool
+var useReadv atomic.Bool
 
-func init() {
+func useReadV() bool {
+	return useReadv.Load()
+}
+
+func reloadEnvSettings() error {
 	const defaultFlagValue = "NOT_DEFINED_AT_ALL"
 	value := platform.NewEnvFlag(platform.UseReadV).GetValue(func() string { return defaultFlagValue })
+	enabled := false
 	switch value {
 	case defaultFlagValue, "auto", "enable":
-		useReadv = true
+		enabled = true
 	}
+	useReadv.Store(enabled)
+	return nil
+}
+
+func init() {
+	platform.RegisterEnvReload(reloadEnvSettings)
 }

common/buf/readv_reader_stub.go

@@ -10,7 +10,9 @@ import (
 	"github.com/xtls/xray-core/features/stats"
 )
 
-const useReadv = false
+func useReadV() bool {
+	return false
+}
 
 func NewReadVReader(reader io.Reader, rawConn syscall.RawConn, counter stats.Counter) Reader {
 	panic("not implemented")

common/platform/env_reload.go

@@ -0,0 +1,40 @@
+package platform
+
+import (
+	"errors"
+	"sync"
+)
+
+var envReloadRegistry = struct {
+	sync.RWMutex
+	handlers []func() error
+}{}
+
+// RegisterEnvReload registers an environment reload handler and runs it once
+// immediately so package defaults keep the same behavior as init-time reads.
+func RegisterEnvReload(handler func() error) {
+	if handler == nil {
+		return
+	}
+	envReloadRegistry.Lock()
+	envReloadRegistry.handlers = append(envReloadRegistry.handlers, handler)
+	envReloadRegistry.Unlock()
+	if err := handler(); err != nil {
+		panic(err)
+	}
+}
+
+// ReloadEnvSettings refreshes all registered environment-backed package state.
+func ReloadEnvSettings() error {
+	envReloadRegistry.RLock()
+	handlers := append([]func() error{}, envReloadRegistry.handlers...)
+	envReloadRegistry.RUnlock()
+
+	var errs []error
+	for _, handler := range handlers {
+		if err := handler(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+	return errors.Join(errs...)
+}

common/xudp/xudp.go

@@ -8,7 +8,7 @@ import (
 	"io"
 	"strconv"
 	"strings"
-	"time"
+	"sync/atomic"
 
 	"github.com/xtls/xray-core/common/buf"
 	"github.com/xtls/xray-core/common/errors"
@@ -27,25 +27,39 @@ var AddrParser = protocol.NewAddressParser(
 )
 
 var (
-	Show    bool
-	BaseKey []byte
+	Show    atomic.Bool
+	baseKey atomic.Value
 )
 
-func init() {
-	if strings.ToLower(platform.NewEnvFlag(platform.XUDPLog).GetValue(func() string { return "" })) == "true" {
-		Show = true
+func reloadEnvSettings() error {
+	Show.Store(strings.ToLower(platform.NewEnvFlag(platform.XUDPLog).GetValue(func() string { return "" })) == "true")
+	raw := platform.NewEnvFlag(platform.XUDPBaseKey).GetValue(func() string { return "" })
+	if raw == "" {
+		ensureBaseKey()
+		return nil
 	}
-	BaseKey = make([]byte, 32)
-	rand.Read(BaseKey)
-	go func() {
-		time.Sleep(100 * time.Millisecond) // this is not nice, but need to give some time for Android to setup ENV
-		if raw := platform.NewEnvFlag(platform.XUDPBaseKey).GetValue(func() string { return "" }); raw != "" {
-			if BaseKey, _ = base64.RawURLEncoding.DecodeString(raw); len(BaseKey) == 32 {
-				return
-			}
-			panic(platform.XUDPBaseKey + ": invalid value (BaseKey must be 32 bytes): " + raw + " len " + strconv.Itoa(len(BaseKey)))
-		}
-	}()
+	key, _ := base64.RawURLEncoding.DecodeString(raw)
+	if len(key) != 32 {
+		return errors.New(platform.XUDPBaseKey + ": invalid value (BaseKey must be 32 bytes): " + raw + " len " + strconv.Itoa(len(key)))
+	}
+	baseKey.Store(append([]byte(nil), key...))
+	return nil
+}
+
+func ensureBaseKey() []byte {
+	if key := baseKey.Load(); key != nil {
+		return key.([]byte)
+	}
+	key := make([]byte, 32)
+	if _, err := rand.Read(key); err != nil {
+		panic(err)
+	}
+	baseKey.Store(key)
+	return key
+}
+
+func init() {
+	platform.RegisterEnvReload(reloadEnvSettings)
 }
 
 func GetGlobalID(ctx context.Context) (globalID [8]byte) {
@@ -54,10 +68,10 @@ func GetGlobalID(ctx context.Context) (globalID [8]byte) {
 	}
 	if inbound := session.InboundFromContext(ctx); inbound != nil && inbound.Source.Network == net.Network_UDP &&
 		(inbound.Name == "dokodemo-door" || inbound.Name == "socks" || inbound.Name == "shadowsocks" || inbound.Name == "tun") {
-		h := blake3.New(8, BaseKey)
+		h := blake3.New(8, ensureBaseKey())
 		h.Write([]byte(inbound.Source.String()))
 		copy(globalID[:], h.Sum(nil))
-		if Show {
+		if Show.Load() {
 			errors.LogInfo(ctx, fmt.Sprintf("XUDP inbound.Source.String(): %v\tglobalID: %v\n", inbound.Source.String(), globalID))
 		}
 	}

core/xray.go

@@ -187,6 +187,9 @@ func NewWithContext(ctx context.Context, config *Config) (*Instance, error) {
 }
 
 func initInstanceWithConfig(config *Config, server *Instance) (bool, error) {
+	if err := platform.ReloadEnvSettings(); err != nil {
+		return true, errors.New("failed to reload environment settings").Base(err)
+	}
 	server.ctx = context.WithValue(server.ctx, "cone",
 		platform.NewEnvFlag(platform.UseCone).GetValue(func() string { return "" }) != "true")
 

features/policy/policy.go

@@ -3,6 +3,7 @@ package policy
 import (
 	"context"
 	"runtime"
+	"sync/atomic"
 	"time"
 
 	"github.com/xtls/xray-core/common/platform"
@@ -82,32 +83,41 @@ func ManagerType() interface{} {
 	return (*Manager)(nil)
 }
 
-var defaultBufferSize int32
+var defaultBufferSize atomic.Int32
 
-func init() {
+func reloadEnvSettings() error {
+	defaultBufferSize.Store(readDefaultBufferSize())
+	return nil
+}
+
+func readDefaultBufferSize() int32 {
 	const defaultValue = -17
 	size := platform.NewEnvFlag(platform.BufferSize).GetValueAsInt(defaultValue)
 
 	switch size {
 	case 0:
-		defaultBufferSize = -1 // For pipe to use unlimited size
+		return -1 // For pipe to use unlimited size
 	case defaultValue: // Env flag not defined. Use default values per CPU-arch.
 		switch runtime.GOARCH {
 		case "arm", "mips", "mipsle":
-			defaultBufferSize = 0
+			return 0
 		case "arm64", "mips64", "mips64le":
-			defaultBufferSize = 4 * 1024 // 4k cache for low-end devices
+			return 4 * 1024 // 4k cache for low-end devices
 		default:
-			defaultBufferSize = 512 * 1024
+			return 512 * 1024
 		}
 	default:
-		defaultBufferSize = int32(size) * 1024 * 1024
+		return int32(size) * 1024 * 1024
 	}
 }
 
+func init() {
+	platform.RegisterEnvReload(reloadEnvSettings)
+}
+
 func defaultBufferPolicy() Buffer {
 	return Buffer{
-		PerConnection: defaultBufferSize,
+		PerConnection: defaultBufferSize.Load(),
 	}
 }
 

infra/conf/env_test.go

@@ -0,0 +1,59 @@
+package conf
+
+import (
+	"encoding/json"
+	"os"
+	"testing"
+)
+
+func TestRootEnvAppliesArbitraryValues(t *testing.T) {
+	const (
+		valueKey = "XRAY_TEST_CONFIG_ENV"
+		emptyKey = "XRAY_TEST_CONFIG_EMPTY"
+	)
+	t.Setenv(valueKey, "before")
+	t.Setenv(emptyKey, "before")
+
+	config := new(Config)
+	if err := json.Unmarshal([]byte(`{
+		"env": {
+			"XRAY_TEST_CONFIG_ENV": "configured",
+			"XRAY_TEST_CONFIG_EMPTY": ""
+		}
+	}`), config); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := config.Build(); err != nil {
+		t.Fatal(err)
+	}
+
+	if got := os.Getenv(valueKey); got != "configured" {
+		t.Fatalf("env %q = %q, want %q", valueKey, got, "configured")
+	}
+	if got := os.Getenv(emptyKey); got != "" {
+		t.Fatalf("env %q = %q, want empty", emptyKey, got)
+	}
+}
+
+func TestEnvConfigOverride(t *testing.T) {
+	base := EnvConfig{
+		"ONE": "one",
+		"TWO": "old",
+	}
+	override := EnvConfig{
+		"TWO":   "new",
+		"THREE": "three",
+	}
+	base.Override(override)
+
+	want := map[string]string{
+		"ONE":   "one",
+		"TWO":   "new",
+		"THREE": "three",
+	}
+	for key, value := range want {
+		if got := base[key]; got != value {
+			t.Fatalf("env %q = %q, want %q", key, got, value)
+		}
+	}
+}

infra/conf/xray.go

@@ -3,6 +3,7 @@ package conf
 import (
 	"context"
 	"encoding/json"
+	"os"
 	"path/filepath"
 	"strings"
 
@@ -379,11 +380,20 @@ func (c *StatsConfig) Build() (*stats.Config, error) {
 	return &stats.Config{}, nil
 }
 
+type EnvConfig map[string]string
+
+func (c EnvConfig) Override(o EnvConfig) {
+	for key, value := range o {
+		c[key] = value
+	}
+}
+
 type Config struct {
 	// Deprecated: Global transport config is no longer used
 	// left for returning error
 	Transport map[string]json.RawMessage `json:"transport"`
 
+	Env              EnvConfig               `json:"env"`
 	LogConfig        *LogConfig              `json:"log"`
 	RouterConfig     *RouterConfig           `json:"routing"`
 	DNSConfig        *DNSConfig              `json:"dns"`
@@ -439,6 +449,12 @@ func (c *Config) Override(o *Config, fn string) {
 	if o.Transport != nil {
 		c.Transport = o.Transport
 	}
+	if o.Env != nil {
+		if c.Env == nil {
+			c.Env = EnvConfig{}
+		}
+		c.Env.Override(o.Env)
+	}
 	if o.Policy != nil {
 		c.Policy = o.Policy
 	}
@@ -514,6 +530,12 @@ func (c *Config) Override(o *Config, fn string) {
 
 // Build implements Buildable.
 func (c *Config) Build() (*core.Config, error) {
+	for key, value := range c.Env {
+		if err := os.Setenv(key, value); err != nil {
+			return nil, errors.New("failed to apply environment configuration").Base(err)
+		}
+	}
+
 	if err := PostProcessConfigureFile(c); err != nil {
 		return nil, errors.New("failed to post-process configuration file").Base(err)
 	}

main/run.go

@@ -36,6 +36,10 @@ The -confdir=dir flag sets a dir with multiple json config
 The -format=json flag sets the format of config files.
 Default "auto".
 
+The config root env object sets process environment variables after all config
+files are parsed. Variables needed to locate or parse config files must be set
+in the process environment before Xray starts.
+
 The -test flag tells Xray to test config files only,
 without launching the server.
 

proxy/freedom/freedom.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"io"
 	"strings"
+	"sync/atomic"
 	"time"
 
 	"github.com/pires/go-proxyproto"
@@ -31,12 +32,24 @@ import (
 )
 
 var (
-	useSplice               bool
+	useSplice               atomic.Bool
 	allNetworks             [8]bool
 	defaultBlockPrivateRule *FinalRule
 	defaultBlockAllRule     *FinalRule
 )
 
+func reloadEnvSettings() error {
+	const defaultFlagValue = "NOT_DEFINED_AT_ALL"
+	value := platform.NewEnvFlag(platform.UseFreedomSplice).GetValue(func() string { return defaultFlagValue })
+	enabled := false
+	switch value {
+	case defaultFlagValue, "auto", "enable":
+		enabled = true
+	}
+	useSplice.Store(enabled)
+	return nil
+}
+
 func init() {
 	common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
 		h := new(Handler)
@@ -48,12 +61,7 @@ func init() {
 		return h, nil
 	}))
 
-	const defaultFlagValue = "NOT_DEFINED_AT_ALL"
-	value := platform.NewEnvFlag(platform.UseFreedomSplice).GetValue(func() string { return defaultFlagValue })
-	switch value {
-	case defaultFlagValue, "auto", "enable":
-		useSplice = true
-	}
+	platform.RegisterEnvReload(reloadEnvSettings)
 
 	for i := range allNetworks {
 		allNetworks[i] = true
@@ -422,7 +430,7 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 
 	responseDone := func() error {
 		defer timer.SetTimeout(plcy.Timeouts.UplinkOnly)
-		if destination.Network == net.Network_TCP && useSplice && proxy.IsRAWTransportWithoutSecurity(conn) { // it would be tls conn in special use case of MITM, we need to let link handle traffic
+		if destination.Network == net.Network_TCP && useSplice.Load() && proxy.IsRAWTransportWithoutSecurity(conn) { // it would be tls conn in special use case of MITM, we need to let link handle traffic
 			var writeConn net.Conn
 			var inTimer *signal.ActivityTimer
 			if inbound := session.InboundFromContext(ctx); inbound != nil && inbound.Conn != nil {

proxy/vmess/outbound/outbound.go

@@ -5,6 +5,7 @@ import (
 	"crypto/hmac"
 	"crypto/sha256"
 	"hash/crc64"
+	"sync/atomic"
 	"time"
 
 	"github.com/xtls/xray-core/common"
@@ -218,10 +219,17 @@ func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer inte
 	return nil
 }
 
-var enablePadding = false
+var enablePadding atomic.Bool
 
 func shouldEnablePadding(s protocol.SecurityType) bool {
-	return enablePadding || s == protocol.SecurityType_AES128_GCM || s == protocol.SecurityType_CHACHA20_POLY1305 || s == protocol.SecurityType_AUTO
+	return enablePadding.Load() || s == protocol.SecurityType_AES128_GCM || s == protocol.SecurityType_CHACHA20_POLY1305 || s == protocol.SecurityType_AUTO
+}
+
+func reloadEnvSettings() error {
+	const defaultFlagValue = "NOT_DEFINED_AT_ALL"
+	paddingValue := platform.NewEnvFlag(platform.UseVmessPadding).GetValue(func() string { return defaultFlagValue })
+	enablePadding.Store(paddingValue != defaultFlagValue)
+	return nil
 }
 
 func init() {
@@ -229,10 +237,5 @@ func init() {
 		return New(ctx, config.(*Config))
 	}))
 
-	const defaultFlagValue = "NOT_DEFINED_AT_ALL"
-
-	paddingValue := platform.NewEnvFlag(platform.UseVmessPadding).GetValue(func() string { return defaultFlagValue })
-	if paddingValue != defaultFlagValue {
-		enablePadding = true
-	}
+	platform.RegisterEnvReload(reloadEnvSettings)
 }

transport/internet/browser_dialer/dialer.go

@@ -27,9 +27,10 @@ type task struct {
 }
 
 var (
-	conns  chan *websocket.Conn
-	server *http.Server
-	mu     sync.Mutex
+	conns       chan *websocket.Conn
+	server      *http.Server
+	currentAddr string
+	mu          sync.Mutex
 )
 
 var upgrader = &websocket.Upgrader{
@@ -47,8 +48,13 @@ func Reload() {
 	mu.Lock()
 	defer mu.Unlock()
 
+	if addr == currentAddr && (addr == "" || server != nil) {
+		return
+	}
+
 	if server != nil {
 		server.Close()
+		server = nil
 	}
 	if HasBrowserDialer() {
 		for len(conns) > 0 {
@@ -60,6 +66,7 @@ func Reload() {
 		}
 		conns = nil
 	}
+	currentAddr = addr
 	if addr != "" {
 		token := uuid.New()
 		csrfToken := token.String()
@@ -220,5 +227,8 @@ func CheckOK(conn *websocket.Conn) error {
 }
 
 func init() {
-	Reload()
+	platform.RegisterEnvReload(func() error {
+		Reload()
+		return nil
+	})
 }