Helper install fails when /Library/PrivilegedHelperTools contains protected third-party helpers (e.g. Wacom) – fixed by #8 #9

Summary

Installing the privileged helper from the GUI fails on a Mac that has the Wacom tablet driver installed. The app reports:

The install script finished, but the helper is still unreachable.
Script output:
chown: /Library/PrivilegedHelperTools/com.wacom.DataStoreMgr.app/Contents/MacOS: Operation not permitted
chown: /Library/PrivilegedHelperTools/com.wacom.DataStoreMgr.app/Contents/Resources/com.wacom.DataStoreMgr.plist: Operation not permitted
chown: /Library/PrivilegedHelperTools/com.wacom.DataStoreMgr.app/Contents/Resources: Operation not permitted
chown: /Library/PrivilegedHelperTools/com.wacom.DataStoreMgr.app/Contents/Info.plist: Operation not permitted
chown: /Library/PrivilegedHelperTools/com.wacom.DataStoreMgr.app/Contents: Operation not permitted
chown: /Library/PrivilegedHelperTools/com.wacom.DataStoreMgr.app: Operation not permitted

Clicking "Install" again fails the same way every time.

Cause

gui/Scripts/install-helper.sh, line 71:

chown -R root:wheel "${TOOLS_DIR}"   # TOOLS_DIR=/Library/PrivilegedHelperTools

This recurses over the whole shared directory, including helpers that belong to other vendors. macOS refuses the change on the Wacom app bundles even for root. Because the script runs with set -euo pipefail, it aborts at that point. The helper binary and dylibs have already been copied, but the LaunchDaemon plist is never installed and launchctl bootstrap never runs, so the helper stays unreachable.

The following chmod 755 "${TOOLS_DIR}" would also change the mode of the shared directory (it is drwxr-xr-t on my machine).

PR #8 fixes exactly this by limiting ownership and permission changes to TetherKit's own files. This issue is mainly a real-world confirmation that the bug blocks installation, and a request to merge #8.

Environment

• TetherKit 0.1.5, installed via brew install XiaoMiku01/tap/tetherkit
• macOS 26.6.2 (25G83), Apple Silicon
• Wacom driver installed; /Library/PrivilegedHelperTools contains com.wacom.DataStoreMgr.app, com.wacom.IOManager.app and com.wacom.UpdateHelper.app (owned by root:staff)

Steps to reproduce

1. Have the Wacom driver (or any other protected helper bundle) in /Library/PrivilegedHelperTools.
2. Launch TetherKit.app and click the helper install button.
3. Enter the admin password.

Workaround

Finish the steps the script skipped, touching only TetherKit's files:

SRC="$(brew --prefix)/opt/tetherkit/TetherKit.app/Contents/Library/HelperTools"
DST=/Library/PrivilegedHelperTools

sudo chown -h root:wheel "$DST"/com.tetherkit.helper "$DST"/libtetherkit*.dylib "$DST"/libusb-*.dylib
sudo chmod 544 "$DST"/com.tetherkit.helper
sudo cp "$SRC"/com.tetherkit.helper.plist /Library/LaunchDaemons/
sudo chown root:wheel /Library/LaunchDaemons/com.tetherkit.helper.plist
sudo chmod 644 /Library/LaunchDaemons/com.tetherkit.helper.plist
sudo launchctl bootstrap system /Library/LaunchDaemons/com.tetherkit.helper.plist

After that the app detects the helper without a restart and tethering works.