feat: cli arg for file permission of socket (#4923)

src/node/app.ts

@@ -11,7 +11,7 @@ import { disposer } from "./http"
 import { isNodeJSErrnoException } from "./util"
 import { handleUpgrade } from "./wsRouter"
 
-type ListenOptions = Pick<DefaultedArgs, "socket" | "port" | "host">
+type ListenOptions = Pick<DefaultedArgs, "socket-mode" | "socket" | "port" | "host">
 
 export interface App extends Disposable {
   /** Handles regular HTTP requests. */
@@ -22,7 +22,7 @@ export interface App extends Disposable {
   server: http.Server
 }
 
-const listen = (server: http.Server, { host, port, socket }: ListenOptions) => {
+const listen = (server: http.Server, { host, port, socket, "socket-mode": mode }: ListenOptions) => {
   return new Promise<void>(async (resolve, reject) => {
     server.on("error", reject)
 
@@ -31,7 +31,16 @@ const listen = (server: http.Server, { host, port, socket }: ListenOptions) => {
       server.off("error", reject)
       server.on("error", (err) => util.logError(logger, "http server error", err))
 
-      resolve()
+      if (socket && mode) {
+        fs.chmod(socket, mode)
+          .then(resolve)
+          .catch((err) => {
+            util.logError(logger, "socket chmod", err)
+            reject(err)
+          })
+      } else {
+        resolve()
+      }
     }
 
     if (socket) {

src/node/cli.ts

@@ -56,6 +56,7 @@ export interface UserProvidedArgs {
   open?: boolean
   "bind-addr"?: string
   socket?: string
+  "socket-mode"?: string
   version?: boolean
   "proxy-domain"?: string[]
   "reuse-window"?: boolean
@@ -175,6 +176,7 @@ const options: Options<Required<UserProvidedArgs>> = {
   port: { type: "number", description: "" },
 
   socket: { type: "string", path: true, description: "Path to a socket (bind-addr will be ignored)." },
+  "socket-mode": { type: "string", description: "File mode of the socket." },
   version: { type: "boolean", short: "v", description: "Display version information." },
   _: { type: "string[]" },
 
@@ -513,6 +515,7 @@ export async function setDefaults(cliArgs: UserProvidedArgs, configArgs?: Config
     args.host = "localhost"
     args.port = 0
     args.socket = undefined
+    args["socket-mode"] = undefined
     args.cert = undefined
     args.auth = AuthType.None
   }