fix(infra): tolerate concurrent tmp dir repair

CHANGELOG.md

@@ -22,6 +22,7 @@ Docs: https://docs.openclaw.ai
 - Telegram: use durable message edits for streaming previews instead of native draft state, so generated replies no longer flicker through draft-to-message transitions that look like duplicates. (#75073) Thanks @obviyus.
 - Telegram: echo preflighted DM voice-note transcripts back to the originating chat, including Telegram DM topic thread metadata, instead of only echoing later media-understanding transcripts. Fixes #75084. Thanks @M-Lietz.
 - Web search: describe `web_search` as using the configured provider instead of hard-coding Brave when DuckDuckGo or another provider is active. Fixes #75088. Thanks @sun-rongyang.
+- Infra/tmp: tolerate concurrent temp-dir permission repairs by rechecking directories that another process already tightened, so parallel ACP subprocess startup no longer throws `Unsafe fallback OpenClaw temp dir`. Fixes #66867. Thanks @Kane808-AI and @jarvisz8.
 
 ## 2026.4.29
 

src/infra/tmp-openclaw-dir.test.ts

@@ -394,6 +394,82 @@ describe("resolvePreferredOpenClawTmpDir", () => {
     expect(warn).toHaveBeenCalledWith(expect.stringContaining("tightened permissions on temp dir"));
   });
 
+  it("uses /tmp/openclaw when another process tightened permissions before repair", () => {
+    const chmodSync = vi.fn();
+    const warn = vi.fn();
+    const tmpdir = vi.fn(() => "/var/fallback");
+    const states = [0o40777, 0o40700, 0o40700];
+    const lstatSync = vi.fn<NonNullable<TmpDirOptions["lstatSync"]>>((target: string) => {
+      if (target === POSIX_OPENCLAW_TMP_DIR) {
+        return makeDirStat({ mode: states.shift() ?? 0o40700 });
+      }
+      return secureDirStat();
+    });
+
+    const resolved = resolvePreferredOpenClawTmpDir({
+      accessSync: vi.fn(),
+      lstatSync,
+      chmodSync,
+      mkdirSync: vi.fn(),
+      getuid: vi.fn(() => 501),
+      tmpdir,
+      warn,
+    });
+
+    expect(resolved).toBe(POSIX_OPENCLAW_TMP_DIR);
+    expect(chmodSync).not.toHaveBeenCalled();
+    expect(warn).not.toHaveBeenCalled();
+    expect(tmpdir).not.toHaveBeenCalled();
+  });
+
+  it("uses fallback when another process tightened fallback permissions before repair", () => {
+    const fallbackPath = fallbackTmp();
+    const chmodSync = vi.fn();
+    const warn = vi.fn();
+    const states = [0o40777, 0o40700, 0o40700];
+
+    const resolved = resolveWithReadOnlyTmpFallback({
+      fallbackPath,
+      fallbackLstatSync: vi.fn(() => makeDirStat({ mode: states.shift() ?? 0o40700 })),
+      chmodSync,
+      warn,
+    });
+
+    expect(resolved).toBe(fallbackPath);
+    expect(chmodSync).not.toHaveBeenCalled();
+    expect(warn).not.toHaveBeenCalled();
+  });
+
+  it("uses /tmp/openclaw when chmod loses a concurrent repair race", () => {
+    const chmodSync = vi.fn((target: string, mode: number) => {
+      if (target === POSIX_OPENCLAW_TMP_DIR && mode === 0o700) {
+        throw nodeErrorWithCode("EPERM");
+      }
+    });
+    const warn = vi.fn();
+    const states = [0o40777, 0o40777, 0o40700];
+    const lstatSync = vi.fn<NonNullable<TmpDirOptions["lstatSync"]>>((target: string) => {
+      if (target === POSIX_OPENCLAW_TMP_DIR) {
+        return makeDirStat({ mode: states.shift() ?? 0o40700 });
+      }
+      return secureDirStat();
+    });
+
+    const resolved = resolvePreferredOpenClawTmpDir({
+      accessSync: vi.fn(),
+      lstatSync,
+      chmodSync,
+      mkdirSync: vi.fn(),
+      getuid: vi.fn(() => 501),
+      tmpdir: vi.fn(() => "/var/fallback"),
+      warn,
+    });
+
+    expect(resolved).toBe(POSIX_OPENCLAW_TMP_DIR);
+    expect(chmodSync).toHaveBeenCalledWith(POSIX_OPENCLAW_TMP_DIR, 0o700);
+    expect(warn).not.toHaveBeenCalled();
+  });
+
   it("throws when the fallback directory cannot be created", () => {
     expect(() =>
       resolvePreferredOpenClawTmpDir({

src/infra/tmp-openclaw-dir.ts

@@ -106,10 +106,24 @@ export function resolvePreferredOpenClawTmpDir(
       if (uid !== undefined && typeof st.uid === "number" && st.uid !== uid) {
         return false;
       }
-      if (typeof st.mode !== "number" || (st.mode & 0o022) === 0) {
+      if (typeof st.mode !== "number") {
         return false;
       }
-      chmodSync(candidatePath, 0o700);
+      if ((st.mode & 0o022) === 0) {
+        return resolveDirState(candidatePath) === "available";
+      }
+      try {
+        chmodSync(candidatePath, 0o700);
+      } catch (chmodErr) {
+        if (
+          isNodeErrorWithCode(chmodErr, "EPERM") ||
+          isNodeErrorWithCode(chmodErr, "EACCES") ||
+          isNodeErrorWithCode(chmodErr, "ENOENT")
+        ) {
+          return resolveDirState(candidatePath) === "available";
+        }
+        throw chmodErr;
+      }
       warn(`[openclaw] tightened permissions on temp dir: ${candidatePath}`);
       return resolveDirState(candidatePath) === "available";
     } catch {