Fix mapped-drive runner launch cwd on Windows

codex-rs/windows-sandbox-rs/src/elevated/runner_client.rs

@@ -10,6 +10,7 @@ use crate::runner_pipe::connect_pipe;
 use crate::runner_pipe::create_named_pipe;
 use crate::runner_pipe::find_runner_exe;
 use crate::runner_pipe::pipe_pair;
+use crate::runner_pipe::prepare_runner_launch_cwd;
 use crate::winutil::quote_windows_arg;
 use crate::winutil::to_wide;
 use anyhow::Result;
@@ -90,6 +91,7 @@ pub(crate) fn spawn_runner_transport(
         .to_str()
         .map(str::to_owned)
         .unwrap_or_else(|| "codex-command-runner.exe".to_string());
+    let runner_launch_cwd = prepare_runner_launch_cwd(codex_home, log_dir);
     let runner_full_cmd = format!(
         "{} {} {}",
         quote_windows_arg(&runner_cmdline),
@@ -98,7 +100,7 @@ pub(crate) fn spawn_runner_transport(
     );
     let mut cmdline_vec = to_wide(&runner_full_cmd);
     let exe_w = to_wide(&runner_cmdline);
-    let cwd_w = to_wide(cwd);
+    let cwd_w = to_wide(&runner_launch_cwd);
     let user_w = to_wide(&sandbox_creds.username);
     let domain_w = to_wide(".");
     let password_w = to_wide(&sandbox_creds.password);
@@ -136,7 +138,11 @@ pub(crate) fn spawn_runner_transport(
             CloseHandle(h_pipe_in);
             CloseHandle(h_pipe_out);
         }
-        return Err(anyhow::anyhow!("CreateProcessWithLogonW failed: {err}"));
+        return Err(anyhow::anyhow!(
+            "CreateProcessWithLogonW failed: {err} (runner_cwd={} requested_cwd={})",
+            runner_launch_cwd.display(),
+            cwd.display()
+        ));
     }
     let expected_runner_pid = pi.dwProcessId;
 

codex-rs/windows-sandbox-rs/src/elevated/runner_pipe.rs

@@ -9,6 +9,7 @@
 
 use crate::helper_materialization::HelperExecutable;
 use crate::helper_materialization::resolve_helper_for_launch;
+use crate::logging::log_note;
 use crate::winutil::resolve_sid;
 use crate::winutil::string_from_sid_bytes;
 use crate::winutil::to_wide;
@@ -44,6 +45,27 @@ pub fn find_runner_exe(codex_home: &Path, log_dir: Option<&Path>) -> PathBuf {
     resolve_helper_for_launch(HelperExecutable::CommandRunner, codex_home, log_dir)
 }
 
+/// Picks a stable local directory for launching the elevated runner itself.
+///
+/// The requested workspace cwd may be a mapped drive or other user-session-specific path that
+/// `CreateProcessWithLogonW` cannot use when starting the sandbox user. The runner only needs a
+/// local bootstrap directory; it receives the real command cwd later in the framed spawn request.
+pub fn prepare_runner_launch_cwd(codex_home: &Path, log_dir: Option<&Path>) -> PathBuf {
+    let runner_cwd = codex_home.join(".sandbox").join("runner-cwd");
+    if let Err(err) = std::fs::create_dir_all(&runner_cwd) {
+        log_note(
+            &format!(
+                "runner launch cwd: failed to create {}: {err}; falling back to {}",
+                runner_cwd.display(),
+                codex_home.display()
+            ),
+            log_dir,
+        );
+        return codex_home.to_path_buf();
+    }
+    runner_cwd
+}
+
 /// Generates a unique named-pipe path used to communicate with the runner process.
 pub fn pipe_pair() -> (String, String) {
     let mut rng = SmallRng::from_entropy();
@@ -133,3 +155,19 @@ pub fn connect_pipe(h: HANDLE, expected_runner_pid: u32) -> io::Result<()> {
     }
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::prepare_runner_launch_cwd;
+
+    #[test]
+    fn prepare_runner_launch_cwd_creates_sandbox_runner_dir() {
+        let tmp = tempfile::tempdir().expect("tempdir");
+        let codex_home = tmp.path().join("codex-home");
+
+        let launch_cwd = prepare_runner_launch_cwd(&codex_home, None);
+
+        assert_eq!(launch_cwd, codex_home.join(".sandbox").join("runner-cwd"));
+        assert!(launch_cwd.is_dir());
+    }
+}