m2dev-server/docs/healthchecks.md

Healthchecks

This repository contains the operational wrapper for the headless login healthcheck. The underlying smoke client lives in m2dev-server-src.

What Exists

Source repository:

• tests/login_smoke.cpp
• binary target: metin_login_smoke

Runtime repository:

• deploy/healthcheck/metin-login-healthcheck.sh

Installed on the VPS:

• /usr/local/sbin/metin-login-healthcheck

What The Headless Login Check Verifies

The check performs the real two-step Metin login flow without a GUI client:

1. Connect to the auth socket.
2. Complete the secure handshake.
3. Send login credentials.
4. Receive AUTH_SUCCESS and the login key.
5. Open a second connection to the channel socket.
6. Complete the secure handshake again.
7. Send LOGIN2 with login + login_key.
8. Verify EMPIRE.
9. Verify LOGIN_SUCCESS4.

This is an end-to-end login verification, not just a TCP port check.

How The Wrapper Works

metin-login-healthcheck.sh does the following:

• creates a temporary account in MariaDB
• runs metin_login_smoke
• verifies a successful auth + channel login
• deletes the temporary account on exit

It is intended for manual admin use on the VPS.

Usage

On the VPS:

ssh mt2
/usr/local/sbin/metin-login-healthcheck

The smoke binary can also be run directly:

sudo -iu mt2.jakubkadlec.dev \
  /home/mt2.jakubkadlec.dev/metin/build/server-src/bin/metin_login_smoke \
  173.249.9.66 11000 11011 <login> <password>

Or with password passed through the environment:

sudo -iu mt2.jakubkadlec.dev env METIN_LOGIN_SMOKE_PASSWORD='<password>' \
  /home/mt2.jakubkadlec.dev/metin/build/server-src/bin/metin_login_smoke \
  173.249.9.66 11000 11011 <login> --password-env=METIN_LOGIN_SMOKE_PASSWORD

Security Notes

This does not open a new public network surface. It is a local operational tool.

Current guardrails:

• no new listening port
• root-only installed wrapper (/usr/local/sbin/metin-login-healthcheck, mode 700)
• temporary credentials
• cleanup trap removes the test account
• wrapper passes the password through environment instead of command-line plaintext
• secrets are not committed to git

Remaining trust boundary:

• anyone with effective root access can still inspect or run the check
• therefore this tool assumes root is already trusted