From a48fa4eb218de63445bbaa9b8eb0b1db0a797057 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thi=C3=AAn=20To=C3=A1n?= <toanalien@gmail.com>
Date: Tue, 12 May 2026 09:35:28 +0700
Subject: [PATCH] fix: handle permission denied when creating DATA_DIR (#1005)
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Fallback to default user directory (~/.9router) when configured
DATA_DIR is not writable (EACCES/EPERM). Other errors still throw.

Co-authored-by: Thiên Toán <toanalien@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
---
 src/lib/dataDir.js | 19 +++++++++++++++++--
 src/mitm/paths.js  | 26 +++++++++++++++++++++-----
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/src/lib/dataDir.js b/src/lib/dataDir.js
index 946a708..d4b0751 100644
--- a/src/lib/dataDir.js
+++ b/src/lib/dataDir.js
@@ -1,14 +1,29 @@
+import fs from "node:fs";
 import path from "path";
 import os from "os";
 
 const APP_NAME = "9router";
 
-export function getDataDir() {
-  if (process.env.DATA_DIR) return process.env.DATA_DIR;
+function defaultDir() {
   if (process.platform === "win32") {
     return path.join(process.env.APPDATA || path.join(os.homedir(), "AppData", "Roaming"), APP_NAME);
   }
   return path.join(os.homedir(), `.${APP_NAME}`);
 }
 
+export function getDataDir() {
+  const configured = process.env.DATA_DIR;
+  if (!configured) return defaultDir();
+  try {
+    fs.mkdirSync(configured, { recursive: true });
+    return configured;
+  } catch (e) {
+    if (e?.code === "EACCES" || e?.code === "EPERM") {
+      console.warn(`[DATA_DIR] '${configured}' not writable → fallback ~/.${APP_NAME}`);
+      return defaultDir();
+    }
+    throw e;
+  }
+}
+
 export const DATA_DIR = getDataDir();
diff --git a/src/mitm/paths.js b/src/mitm/paths.js
index 3c667f4..892c225 100644
--- a/src/mitm/paths.js
+++ b/src/mitm/paths.js
@@ -1,13 +1,29 @@
+const fs = require("fs");
 const path = require("path");
 const os = require("os");
 
-// Single source of truth for data directory — matches localDb.js logic
-function getDataDir() {
-  if (process.env.DATA_DIR) return process.env.DATA_DIR;
+const APP_NAME = "9router";
+
+function defaultDir() {
   if (process.platform === "win32") {
-    return path.join(process.env.APPDATA || path.join(os.homedir(), "AppData", "Roaming"), "9router");
+    return path.join(process.env.APPDATA || path.join(os.homedir(), "AppData", "Roaming"), APP_NAME);
+  }
+  return path.join(os.homedir(), `.${APP_NAME}`);
+}
+
+function getDataDir() {
+  const configured = process.env.DATA_DIR;
+  if (!configured) return defaultDir();
+  try {
+    fs.mkdirSync(configured, { recursive: true });
+    return configured;
+  } catch (e) {
+    if (e?.code === "EACCES" || e?.code === "EPERM") {
+      console.warn(`[DATA_DIR] '${configured}' not writable → fallback ~/.${APP_NAME}`);
+      return defaultDir();
+    }
+    throw e;
   }
-  return path.join(os.homedir(), ".9router");
 }
 
 const DATA_DIR = getDataDir();