Files
claude-code/src/utils/udsMessaging.ts
2026-05-01 21:39:30 +08:00

743 lines
21 KiB
TypeScript

/**
* UDS Messaging Layer — Unix Domain Socket IPC for Claude Code instances.
*
* Each session auto-creates a UDS server so peer sessions can send messages.
* Protocol: newline-delimited JSON (NDJSON), one message per line.
*
* Socket path defaults to a tmpdir-based path derived from the session PID,
* but can be overridden via --messaging-socket-path.
*/
import { createHash, randomBytes, timingSafeEqual } from 'crypto'
import { createServer, type Server, type Socket } from 'net'
import {
chmod,
lstat,
mkdir,
open,
readFile,
rename,
unlink,
} from 'fs/promises'
import { dirname, join } from 'path'
import { tmpdir } from 'os'
import { registerCleanup } from './cleanupRegistry.js'
import { logForDebugging } from './debug.js'
import { errorMessage } from './errors.js'
import { getClaudeConfigHomeDir } from './envUtils.js'
import { attachNdjsonFramer } from './ndjsonFramer.js'
import { attachUdsResponseReader } from './udsResponseReader.js'
import { logError } from './log.js'
import { jsonParse, jsonStringify } from './slowOperations.js'
// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------
export type UdsMessageType =
| 'text'
| 'notification'
| 'query'
| 'response'
| 'error'
| 'ping'
| 'pong'
export type UdsMessage = {
/** Discriminator */
type: UdsMessageType
/** Payload text / JSON content */
data?: string
/** Sender socket path (so the receiver can reply) */
from?: string
/** ISO timestamp */
ts?: string
/** Optional metadata */
meta?: Record<string, unknown>
}
export type UdsInboxEntry = {
id: string
message: UdsMessage
receivedAt: number
status: 'pending' | 'processed'
}
// ---------------------------------------------------------------------------
// Module state
// ---------------------------------------------------------------------------
let server: Server | null = null
let socketPath: string | null = null
let onEnqueueCb: (() => void) | null = null
const clients = new Set<Socket>()
const inbox: UdsInboxEntry[] = []
let nextId = 1
let defaultSocketPath: string | null = null
let authToken: string | null = null
let capabilityFilePath: string | null = null
let inboxBytes = 0
export const MAX_UDS_INBOX_ENTRIES = 1_000
export const MAX_UDS_FRAME_BYTES = 64 * 1024
export const MAX_UDS_INBOX_BYTES = 2 * 1024 * 1024
export const MAX_UDS_CLIENTS = 128
export const UDS_AUTH_TIMEOUT_MS = 2_000
export const UDS_IDLE_TIMEOUT_MS = 30_000
// ---------------------------------------------------------------------------
// Public API — socket path helpers
// ---------------------------------------------------------------------------
/**
* Default socket path based on PID, placed in a tmpdir subdirectory so it
* survives across config-home changes and avoids polluting ~/.claude.
*
* On Windows, Node.js requires named pipe paths in the `\\.\pipe\` namespace;
* file-system paths like `C:\...\Temp\x.sock` cause EACCES. Bun handles both
* transparently, but we use the pipe format on Windows for Node.js compat.
*/
export function getDefaultUdsSocketPath(): string {
if (defaultSocketPath) return defaultSocketPath
const nonce = randomBytes(16).toString('hex')
if (process.platform === 'win32') {
defaultSocketPath = `\\\\.\\pipe\\claude-code-${process.pid}-${nonce}`
return defaultSocketPath
}
defaultSocketPath = join(
tmpdir(),
'claude-code-socks',
`${process.pid}-${nonce}`,
'messaging.sock',
)
return defaultSocketPath
}
/**
* Returns the socket path of the currently running server, or undefined
* if the server has not been started.
*/
export function getUdsMessagingSocketPath(): string | undefined {
return socketPath ?? undefined
}
export function formatUdsAddress(socket: string): string {
return `uds:${socket}`
}
export function parseUdsTarget(target: string): {
socketPath: string
} {
if (target.includes('#token=')) {
throw new Error(
'UDS target must not include an inline auth token; use the ListPeers address',
)
}
return { socketPath: target }
}
function getCapabilityDir(): string {
return join(getClaudeConfigHomeDir(), 'messaging-capabilities')
}
function getCapabilityPath(socket: string): string {
const digest = createHash('sha256').update(socket).digest('hex')
return join(getCapabilityDir(), `${digest}.json`)
}
function isNotFound(error: unknown): boolean {
return (
typeof error === 'object' &&
error !== null &&
(error as NodeJS.ErrnoException).code === 'ENOENT'
)
}
async function assertPrivateCapabilityDir(dir: string): Promise<void> {
let stat: Awaited<ReturnType<typeof lstat>>
try {
stat = await lstat(dir)
} catch (error) {
if (!isNotFound(error)) throw error
await mkdir(dir, { recursive: true, mode: 0o700 })
stat = await lstat(dir)
}
assertPrivateDirectory(stat, dir, 'capability directory')
await chmod(dir, 0o700)
}
function assertPrivateDirectory(
stat: Awaited<ReturnType<typeof lstat>>,
dir: string,
label: string,
): void {
if (!stat.isDirectory() || stat.isSymbolicLink()) {
throw new Error(
`[udsMessaging] ${label} is not a private directory: ${dir}`,
)
}
if (process.platform !== 'win32') {
const broadMode = Number(stat.mode) & 0o077
if (broadMode !== 0) {
throw new Error(
`[udsMessaging] ${label} permissions are too broad: ${dir}`,
)
}
if (
typeof process.getuid === 'function' &&
Number(stat.uid) !== process.getuid()
) {
throw new Error(
`[udsMessaging] ${label} owner does not match current user: ${dir}`,
)
}
}
}
async function writePrivateFileExclusive(
path: string,
content: string,
): Promise<void> {
const handle = await open(path, 'wx', 0o600)
try {
await handle.writeFile(content, 'utf-8')
} finally {
await handle.close()
}
await chmod(path, 0o600)
}
async function ensureSocketParent(path: string): Promise<void> {
const dir = dirname(path)
try {
const stat = await lstat(dir)
if (!stat.isDirectory() || stat.isSymbolicLink()) {
throw new Error(`[udsMessaging] socket parent is not a directory: ${dir}`)
}
assertPrivateDirectory(stat, dir, 'socket parent')
return
} catch (error) {
if (!isNotFound(error)) throw error
}
await mkdir(dir, { recursive: true, mode: 0o700 })
await chmod(dir, 0o700)
}
async function writeCapabilityFile(
socket: string,
token: string,
): Promise<void> {
const dir = getCapabilityDir()
await assertPrivateCapabilityDir(dir)
const target = getCapabilityPath(socket)
const temp = `${target}.${process.pid}.${randomBytes(8).toString('hex')}.tmp`
try {
await writePrivateFileExclusive(
temp,
jsonStringify({ socketPath: socket, authToken: token }),
)
await rename(temp, target)
} catch (error) {
try {
await unlink(temp)
} catch {
// Temp file may not exist if exclusive creation failed.
}
throw error
}
capabilityFilePath = target
}
export async function readUdsCapabilityToken(
socket: string,
): Promise<string | undefined> {
try {
const parsed = jsonParse(
await readFile(getCapabilityPath(socket), 'utf-8'),
) as Record<string, unknown>
if (parsed.socketPath === socket && typeof parsed.authToken === 'string') {
return parsed.authToken
}
} catch {
// Missing or unreadable capability file means the peer is not addressable.
}
return undefined
}
// ---------------------------------------------------------------------------
// Inbox
// ---------------------------------------------------------------------------
/**
* Register a callback invoked whenever a message is enqueued into the inbox.
* Used by the print/SDK query loop to kick off processing.
*/
export function setOnEnqueue(cb: (() => void) | null): void {
onEnqueueCb = cb
}
/**
* Drain all pending inbox messages and release retained history.
*/
export function drainInbox(): UdsInboxEntry[] {
const pending = inbox.splice(0, inbox.length)
inboxBytes = 0
for (const entry of pending) {
entry.status = 'processed'
}
return pending
}
function getMessageBytes(message: UdsMessage): number {
return Buffer.byteLength(jsonStringify(message), 'utf8')
}
function enqueueInboxEntry(entry: UdsInboxEntry): boolean {
const entryBytes = getMessageBytes(entry.message)
if (
entryBytes > MAX_UDS_FRAME_BYTES ||
inbox.length >= MAX_UDS_INBOX_ENTRIES ||
inboxBytes + entryBytes > MAX_UDS_INBOX_BYTES
) {
logError(
new Error(
`[udsMessaging] inbox full (${inbox.length}/${MAX_UDS_INBOX_ENTRIES}, ${inboxBytes}/${MAX_UDS_INBOX_BYTES} bytes); dropping message type=${entry.message.type}`,
),
)
return false
}
inbox.push(entry)
inboxBytes += entryBytes
return true
}
function ensureAuthToken(): string {
if (!authToken) {
authToken = randomBytes(32).toString('hex')
}
return authToken
}
function getMessageAuthToken(message: UdsMessage): string | undefined {
const token = message.meta?.authToken
return typeof token === 'string' ? token : undefined
}
function isAuthorizedMessage(message: UdsMessage): boolean {
const provided = getMessageAuthToken(message)
if (!provided || !authToken) return false
const providedBuffer = Buffer.from(provided, 'utf8')
const expectedBuffer = Buffer.from(authToken, 'utf8')
if (providedBuffer.length !== expectedBuffer.length) return false
return timingSafeEqual(providedBuffer, expectedBuffer)
}
function writeSocketMessage(socket: Socket, message: UdsMessage): void {
if (socket.destroyed) return
socket.write(jsonStringify(message) + '\n')
}
function writeSocketMessageAndDestroy(
socket: Socket,
message: UdsMessage,
): void {
if (socket.destroyed) return
socket.write(jsonStringify(message) + '\n', () => {
if (!socket.destroyed) socket.destroy()
})
}
function writeSocketErrorAndDestroy(socket: Socket, data: string): void {
writeSocketMessageAndDestroy(socket, {
type: 'error',
data,
ts: new Date().toISOString(),
})
}
function unrefTimer(timer: ReturnType<typeof setTimeout>): void {
const maybeUnref = (timer as { unref?: () => void }).unref
if (typeof maybeUnref === 'function') {
maybeUnref.call(timer)
}
}
async function closeServer(serverToClose: Server): Promise<void> {
await new Promise<void>(resolve => {
serverToClose.close(() => resolve())
})
}
async function removeSocketPath(path: string): Promise<void> {
if (process.platform === 'win32') return
try {
await unlink(path)
} catch {
// Already gone.
}
}
function stripAuthToken(message: UdsMessage): UdsMessage {
const { authToken: _authToken, ...metaWithoutAuth } = message.meta ?? {}
return {
...message,
meta: Object.keys(metaWithoutAuth).length > 0 ? metaWithoutAuth : undefined,
}
}
function withRequestAuthToken(message: UdsMessage, token: string): UdsMessage {
return {
...message,
meta: {
...message.meta,
authToken: token,
},
}
}
// ---------------------------------------------------------------------------
// Server
// ---------------------------------------------------------------------------
/**
* Start the UDS messaging server on the given socket path.
*
* Exports `CLAUDE_CODE_MESSAGING_SOCKET` into `process.env` so child
* processes (hooks, spawned agents) can discover and connect back.
*/
export async function startUdsMessaging(
path: string,
opts?: { isExplicit?: boolean },
): Promise<void> {
if (server) {
logForDebugging('[udsMessaging] server already running, skipping start')
return
}
// Ensure parent directory exists (skip on Windows — pipe paths aren't files)
if (process.platform !== 'win32') {
await ensureSocketParent(path)
}
// Clean up stale socket file (skip on Windows — pipe paths aren't files)
if (process.platform !== 'win32') {
try {
await unlink(path)
} catch {
// ENOENT is fine
}
}
const token = ensureAuthToken()
let startedServer: Server | null = null
let exportedSocketEnv = false
try {
await new Promise<void>((resolve, reject) => {
const srv = createServer(socket => {
if (clients.size >= MAX_UDS_CLIENTS) {
logForDebugging(
`[udsMessaging] rejected client: ${clients.size}/${MAX_UDS_CLIENTS} clients already connected`,
)
socket.destroy()
return
}
clients.add(socket)
logForDebugging(
`[udsMessaging] client connected (total: ${clients.size})`,
)
let authenticated = false
let closing = false
const closeWithError = (data: string): void => {
if (closing || socket.destroyed) return
closing = true
socket.pause()
writeSocketErrorAndDestroy(socket, data)
}
const authTimer = setTimeout(() => {
if (authenticated || socket.destroyed) return
logForDebugging('[udsMessaging] closing unauthenticated idle client')
closeWithError('authentication timeout')
}, UDS_AUTH_TIMEOUT_MS)
unrefTimer(authTimer)
socket.setTimeout(UDS_IDLE_TIMEOUT_MS, () => {
logForDebugging('[udsMessaging] closing idle client')
closeWithError('idle timeout')
})
attachNdjsonFramer<UdsMessage>(
socket,
msg => {
if (!isAuthorizedMessage(msg)) {
logForDebugging(
`[udsMessaging] rejected unauthenticated message type=${msg.type}`,
)
closeWithError('unauthorized')
return
}
if (!authenticated) {
authenticated = true
clearTimeout(authTimer)
}
// Handle ping with automatic pong
if (msg.type === 'ping') {
writeSocketMessage(socket, {
type: 'pong',
from: socketPath ?? undefined,
ts: new Date().toISOString(),
})
return
}
// Enqueue into inbox
const sanitizedMessage = stripAuthToken(msg)
const entry: UdsInboxEntry = {
id: `uds-${nextId++}`,
message: sanitizedMessage,
receivedAt: Date.now(),
status: 'pending',
}
if (!enqueueInboxEntry(entry)) {
closeWithError('inbox full')
return
}
logForDebugging(
`[udsMessaging] enqueued message type=${msg.type} from=${msg.from ?? 'unknown'}`,
)
writeSocketMessage(socket, {
type: 'response',
data: 'ok',
ts: new Date().toISOString(),
meta: { id: entry.id },
})
onEnqueueCb?.()
},
text => jsonParse(text) as UdsMessage,
{
maxFrameBytes: MAX_UDS_FRAME_BYTES,
onFrameError: error => {
logForDebugging(`[udsMessaging] ${error.message}`)
closeWithError(error.message)
},
onInvalidFrame: error => {
logForDebugging(
`[udsMessaging] invalid client frame: ${errorMessage(error)}`,
)
closeWithError('invalid frame')
},
destroyOnFrameError: false,
},
)
socket.on('close', () => {
clearTimeout(authTimer)
clients.delete(socket)
})
socket.on('error', err => {
clearTimeout(authTimer)
clients.delete(socket)
logForDebugging(`[udsMessaging] client error: ${errorMessage(err)}`)
})
})
const rejectBeforeListen = (error: Error): void => {
reject(error)
}
const logRuntimeError = (error: Error): void => {
logForDebugging(
`[udsMessaging] server error on ${path}${opts?.isExplicit ? ' (explicit)' : ''}: ${errorMessage(error)}`,
)
}
srv.once('error', rejectBeforeListen)
srv.listen(path, () => {
void (async () => {
try {
if (process.platform !== 'win32') {
// Restrict socket permissions to owner-only. On macOS with
// Node.js v22, the listen callback may fire before the socket
// file is visible on disk (observed with nested tmpdir paths).
// The parent directory is already 0o700, so skipping chmod when
// the file is not yet visible is safe.
try {
await chmod(path, 0o600)
} catch (err: unknown) {
if (
!(
err instanceof Error &&
(err as NodeJS.ErrnoException).code === 'ENOENT'
)
) {
throw err
}
logForDebugging(
`[udsMessaging] chmod skipped: socket file not yet visible at ${path}`,
)
}
}
srv.off('error', rejectBeforeListen)
srv.on('error', logRuntimeError)
server = srv
startedServer = srv
resolve()
} catch (error) {
srv.off('error', rejectBeforeListen)
const closeError =
error instanceof Error ? error : new Error(errorMessage(error))
let rejected = false
const rejectOnce = (): void => {
if (rejected) return
rejected = true
reject(closeError)
}
const fallback = setTimeout(rejectOnce, 1_000)
unrefTimer(fallback)
srv.close(() => {
clearTimeout(fallback)
rejectOnce()
})
}
})()
})
})
await writeCapabilityFile(path, token)
socketPath = path
// Export so child processes can discover the socket only after the
// capability file exists and the listener is ready.
process.env.CLAUDE_CODE_MESSAGING_SOCKET = path
exportedSocketEnv = true
logForDebugging(
`[udsMessaging] server listening on ${path}${opts?.isExplicit ? ' (explicit)' : ''}`,
)
} catch (error) {
if (capabilityFilePath) {
try {
await unlink(capabilityFilePath)
} catch {
// Already gone.
}
capabilityFilePath = null
}
if (startedServer) {
await closeServer(startedServer)
}
if (server === startedServer) {
server = null
}
await removeSocketPath(path)
if (exportedSocketEnv) {
delete process.env.CLAUDE_CODE_MESSAGING_SOCKET
}
socketPath = null
defaultSocketPath = null
authToken = null
throw error
}
// Register cleanup so the socket file is removed on exit
registerCleanup(async () => {
await stopUdsMessaging()
})
}
/**
* Stop the UDS messaging server and clean up the socket file.
*/
export async function stopUdsMessaging(): Promise<void> {
defaultSocketPath = null
if (!server) return
// Close all connected clients
for (const socket of clients) {
socket.destroy()
}
clients.clear()
await new Promise<void>(resolve => {
server!.close(() => resolve())
})
server = null
inbox.length = 0
inboxBytes = 0
onEnqueueCb = null
// Remove socket file (skip on Windows — pipe paths aren't files)
if (socketPath) {
await removeSocketPath(socketPath)
delete process.env.CLAUDE_CODE_MESSAGING_SOCKET
logForDebugging(
`[udsMessaging] server stopped, socket removed: ${socketPath}`,
)
socketPath = null
authToken = null
}
if (capabilityFilePath) {
try {
await unlink(capabilityFilePath)
} catch {
// Already gone
}
capabilityFilePath = null
}
}
/**
* Send a UDS message to a specific socket path (outbound — used when this
* session wants to push a message to a peer's server).
*/
export async function sendUdsMessage(
targetSocketPath: string,
message: UdsMessage,
opts: { authToken?: string } = {},
): Promise<void> {
const { createConnection } = await import('net')
const token = opts.authToken ?? authToken
if (!token) {
throw new Error('Cannot send UDS message without auth token')
}
const outbound = withRequestAuthToken(
{
...message,
from: message.from ?? socketPath ?? undefined,
ts: message.ts ?? new Date().toISOString(),
},
token,
)
return new Promise<void>((resolve, reject) => {
let settled = false
let conn: ReturnType<typeof createConnection>
const finish = (error?: Error): void => {
if (settled) return
settled = true
if (error) {
conn.destroy(error)
reject(error)
} else {
conn.end()
resolve()
}
}
conn = createConnection(targetSocketPath, () => {
conn.write(jsonStringify(outbound) + '\n', err => {
if (err) finish(err)
})
})
attachUdsResponseReader(conn, {
maxFrameBytes: MAX_UDS_FRAME_BYTES,
acceptPong: true,
onSettled: finish,
})
// Timeout so we don't hang on unreachable sockets
conn.setTimeout(5000, () => {
finish(new Error('Connection timed out'))
})
})
}