# MeshBay — Windows Port

> Status: **audit complete, work not started.**
> Created 2026-09-03 from a full codebase scan.
> This document is both the audit results and the implementation plan.
> It does not repeat the design decisions already in `desktop-client-v1.md`
> (§6.8, §7.5, decisions E8/E12) — read that first.

---

## 1. Current state — what is already portable

The bulk of the codebase is ready. The architecture documents said "exFAT/NTFS
and Windows are the common case" (decision E12) and the code reflects it where
it matters most:

| Area | Status | Notes |
|---|---|---|
| `meshbay_common/paths.py` | **Ready** | `fold()`, `nfc()`, `long_path()` with `\\?\` prefix, `WINDOWS_RESERVED`, `sanitize_for_download()`, `find_fold_collisions()` |
| `meshbay_common/` (all other modules) | **Ready** | Crypto, protocol, keyderive — no OS dependency |
| `roots.py` | **Ready** | Uses `fold()`, `portable_name_problem()`, `as_posix()` for virtual paths, Windows drive examples in docstrings |
| `indexer/indexer.py` | **Ready** | `as_posix()` for index paths, `long_path()` for file I/O, reconciliation loop for dropped `ReadDirectoryChangesW` events |
| Transport (WebRTC, QUIC, MNP) | **Ready** | asyncio + aiortc, no platform dependency |
| Roster, bundle store, audit, chat store | **Ready** | SQLite + pathlib throughout |
| `test_paths.py` | **Ready** | Case folding, NFC, reserved names, reserved characters, trailing dot/space — already covers Windows filesystem rules |
| Electron `preload.js` | **Ready** | Pure IPC bridge, no platform code |
| Electron `safeStorage` | **Ready** | `secretsBackend()` (`src/main.js:229-232`) already handles `win32 → 'dpapi'` |
| Electron `app://` protocol | **Ready** | Cross-platform Electron API |
| Electron `scripts/sync-ui.js` | **Ready** | Uses `path.join`/`path.resolve` |
| Hub (`meshbay-hub`) | **N/A** | Server-only, stays Linux |

---

## 2. Blockers — will crash or fail on Windows

### 2.1 Hardcoded XDG paths (~20 locations)

The central problem. Every default path assumes `~/.config/meshbay` and
`~/.local/share/meshbay`. On Windows these must be `%LOCALAPPDATA%\meshbay`
(or `%APPDATA%\meshbay` for roaming config).

**Python — meshbay-node:**

| File | Line | Path |
|---|---|---|
| `config.py` | 28 | `DEFAULT_CONFIG_PATH = Path.home() / ".config" / "meshbay" / "node.toml"` |
| `config.py` | 237 | `data_dir` default → `~/.local/share/meshbay` |
| `keystore.py` | 60 | `DEFAULT_KEYSTORE_PATH` → `~/.config/meshbay/keystore.enc` |
| `keystore.py` | 61 | `DEFAULT_UNLOCK_FILE` → `~/.config/meshbay/unlock.key` |
| `hub_client.py` | 64 | `cache_dir` → `~/.config/meshbay` |
| `tls_cert.py` | 26-27 | `DEFAULT_CERT` / `DEFAULT_KEY` → `~/.config/meshbay/` |
| `quic_server.py` | 610-611 | Fallback cert/key paths → `~/.config/meshbay/` |
| `daemon.py` | 1760-1762 | `reset` command hardcodes `~/.config`, `~/.local/share`, `~/.local/state` |

**JavaScript — meshbay-client:**

| File | Line | Path |
|---|---|---|
| `src/main.js` | 700 | `nodeConfigPath()` → `os.homedir() + '/.config/meshbay/node.toml'` |
| `src/main.js` | 706 | `readNodeConfig()` → `os.homedir() + '/.local/share/meshbay'` |
| `src/main.js` | 753 | `findNodeBinary()` → `os.homedir() + '/.local/bin/meshbay-node'` |
| `src/main.js` | 836 | data dir fallback → `os.homedir() + '/.local/share/meshbay'` |
| `src/main.js` | 855-856 | `provisionNode()` → hardcoded config and data dirs |

**Fix:** one `platform_dirs()` function in Python (`meshbay_common` or
`meshbay_node`) and one in JS, each returning `{config_dir, data_dir,
state_dir, bin_dir}` per platform. Called from a single place; every default
path derived from it. See §5.1.

### 2.2 Signal handling in the daemon

`daemon.py:679-680` — `loop.add_signal_handler(SIGINT, SIGTERM)` raises
`NotImplementedError` on Windows' `ProactorEventLoop`. SIGHUP (`daemon.py:683-687`)
is already guarded with `try/except`; SIGINT/SIGTERM is not.

**Fix:** on Windows, use `signal.signal(signal.SIGINT, handler)` — works with
`ProactorEventLoop`. Or use `SetConsoleCtrlHandler` via ctypes for
`CTRL_C_EVENT` and `CTRL_CLOSE_EVENT`. See §5.2.

### 2.3 systemd-hardwired daemon lifecycle

The CLI and the Electron client assume systemd for start/stop/reload/restart:

**Python CLI (`daemon.py`):**

| Line | What |
|---|---|
| 1590-1605 | `_systemctl_user()` → `subprocess.run(["systemctl", "--user", ...])` |
| 1806 | `reset` → `systemctl --user disable --now` |
| 2058 | `reload` → `_systemctl_user("reload", ...)` |
| 2070 | `restart-daemon` → `_systemctl_user("restart", ...)` |
| 1751 | `init` prints `systemctl --user enable --now` instructions |

**Electron (`src/main.js`):**

| Line | IPC handler |
|---|---|
| 763 | `node:installed` → `systemctl --user show` (returns `{ installed: false }` on non-Linux) |
| 781 | `node:service-status` → `systemctl --user show` (returns `{ supported: false }`) |
| 806-810 | `node:service-stop` → throws on non-Linux |
| 820-824 | `node:service-restart` → throws on non-Linux |
| 898-954 | `node:start` → throws on non-Linux, then various systemctl calls |

The Electron guards are correct (no crash on Windows), but the entire Node
management panel is inoperative. **This is the largest piece of new code in
the port.** See §5.3.

### 2.4 `which` command in Electron

`src/main.js:756` — `execFile('which', ['meshbay-node'])` to locate the
binary. `which` does not exist on Windows.

**Fix:** use `where.exe` on Windows, or use a JS-native lookup
(`child_process.execFileSync` with `process.env.PATH` split on `;`). See §5.1.

### 2.5 Electron packaging — no Windows target

`package.json:11` — `"dist": "npm run sync-ui && electron-builder --linux deb rpm"`.
The `build` section has only `linux`, `deb`, and `rpm` keys. No `build.win`,
no NSIS/MSI configuration.

`packaging/` contains only Linux artifacts: `deb/`, `rpm/`, `systemd/`,
`firewall/`, `caddy/`, `desktop/`.

**Fix:** add `build.win` to `package.json` with NSIS per-user target, and a
`packaging/win/` directory. See §5.4.

---

## 3. Needs work — no crash, but wrong or incomplete behavior

### 3.1 File permissions (`chmod 0o600`)

`os.chmod(path, 0o600)` and `path.chmod(0o600)` are no-ops on NTFS — the
mode bits are ignored. The files are left with default Windows permissions
(readable by the user and administrators), which is acceptable for per-user
data but not explicit.

| File | Line | What |
|---|---|---|
| `keystore.py` | 236 | keystore file |
| `keystore.py` | 97-98 | **Reads** `st_mode` and warns if not `"600"` — will always warn on Windows |
| `roster.py` | 918 | roster database |
| `tls_cert.py` | 67-68 | TLS cert and key |
| `daemon.py` | 221 | UI token file |
| `daemon.py` | 1726, 1734 | node.toml and unlock.key during `init` |
| `src/main.js` | 193, 226, 866, 882, 888 | config files |

**Fix:** guard `chmod` calls with `sys.platform != "win32"`. For the
`keystore.py:97` permission check, skip the mode verification on Windows.
Windows ACLs (via `icacls` or `pywin32`) are an option for defense in depth
but not required — the files are under `%LOCALAPPDATA%`, which is per-user
by default. See §5.5.

### 3.2 ffmpeg/ffprobe discovery

All calls use bare `"ffmpeg"` / `"ffprobe"` strings:

| File | Line |
|---|---|
| `media_probe.py` | 51 |
| `indexer/enrich.py` | 165 |
| `webrtc_server.py` | 3468, 4387, 4607 |
| `quic_server.py` | 559 |

Python's `subprocess` resolves `.exe` transparently on Windows, so these work
**if ffmpeg is in `%PATH%`**. But there is no startup check and no clear error
message if it is missing.

**Fix:** add a `node.toml` config key `[node] ffmpeg_path` with a default of
`"ffmpeg"`, checked at startup with `shutil.which()`. Report a clear error
at daemon startup if not found. See §5.6.

### 3.3 CLI messages assume Linux

`daemon.py:1751` — `init` unconditionally prints `systemctl --user enable
--now meshbay-node`. The example config (`config.py:91-109`) uses Unix paths
(`/home/user/Media`, `/run/media/user/USB/`).

**Fix:** platform-conditional messages and example paths. Minor.

---

## 4. Not a problem — confirmed portable

These were checked and need no work:

- **watchdog `Observer`** — auto-selects `ReadDirectoryChangesW` on Windows.
  The reconciliation scan (`_reconcile_loop`, `indexer.py:513`) already
  compensates for dropped events.
- **`asyncio.create_subprocess_exec`** — works on Windows with
  `ProactorEventLoop` (default since Python 3.10). `proc.kill()` sends
  `TerminateProcess` rather than SIGKILL — functionally correct.
- **`as_posix()` for index paths** — the MNP protocol uses forward slashes;
  the indexer already normalizes (`indexer.py:128`).
- **SQLite** — fully cross-platform.
- **aiortc** — pure Python, no OS dependency.
- **No Unix-only imports** — no `fcntl`, `grp`, `pwd`, `resource` anywhere
  in the codebase.
- **`proc.kill()` semantics** — different (no signal) but the pipe-draining
  and timeout patterns already in place handle it.

---

## 5. Implementation plan

### Principles

1. **Write under Linux, validate under Windows.** The code changes are
   testable on Linux with `sys.platform` mocking. The Windows VM is for
   integration testing, packaging and visual validation.
2. **One function, one place.** Platform-specific logic is concentrated in
   helper functions, never scattered across call sites.
3. **No new files if a function in an existing module suffices.**
4. **Tests must run on both platforms.** Anything that touches signals or
   paths must have a `@pytest.mark.skipif` for the platform it cannot run
   on, not a crash.

### 5.1 Platform directories (W1)

**Scope:** `meshbay_node` + `meshbay-client`

Create `meshbay_node/platform.py`:

```python
def config_dir() -> Path:
    if sys.platform == "win32":
        return Path(os.environ.get("LOCALAPPDATA", Path.home())) / "meshbay"
    return Path.home() / ".config" / "meshbay"

def data_dir() -> Path: ...
def state_dir() -> Path: ...
```

Replace every hardcoded XDG path in `config.py`, `keystore.py`,
`hub_client.py`, `tls_cert.py`, `quic_server.py`, `daemon.py` with calls
to these functions.

In `src/main.js`, equivalent `meshbayConfigDir()` / `meshbayDataDir()` using
`process.env.LOCALAPPDATA` on win32, `os.homedir() + '/.config/meshbay'`
elsewhere. Replace the 8 hardcoded locations.

For `findNodeBinary()`: use `where.exe meshbay-node` on Windows,
`which meshbay-node` on others.

**Estimated scope:** ~20 call sites, mechanical replacement.

### 5.2 Signal handling (W2)

**Scope:** `daemon.py` only

```python
if sys.platform == "win32":
    signal.signal(signal.SIGINT, lambda *_: stop_event.set())
    signal.signal(signal.SIGTERM, lambda *_: stop_event.set())
else:
    for sig in (signal.SIGINT, signal.SIGTERM):
        loop.add_signal_handler(sig, stop_event.set)
```

SIGHUP is already guarded. No other signal handling in the codebase.

**Estimated scope:** ~10 lines changed.

### 5.3 Daemon lifecycle on Windows (W3)

**Scope:** `daemon.py` CLI + `src/main.js` IPC handlers

This is the largest work item. Two modes, matching `desktop-client-v1.md`
§7.5:

#### Per-user mode (default)

The daemon runs as a regular process. Autostart via:
- **Startup folder shortcut**, or
- **Task Scheduler** logon task (preferred — survives "disable startup
  apps" and has retry semantics).

The Electron client manages this through Task Scheduler COM or `schtasks.exe`:
- `node:start` → `schtasks /create /tn MeshBayNode /tr "meshbay-node run" /sc ONLOGON /rl LIMITED`
- `node:service-stop` → `schtasks /end /tn MeshBayNode` + kill the process
- `node:service-status` → `schtasks /query /tn MeshBayNode` + check if the process is running
- `node:installed` → check if `meshbay-node.exe` exists in known locations

The Python CLI equivalents:
- `reload` on Windows → find the running daemon process and send a custom
  event (named pipe or a reload-flag file the daemon watches), or just
  restart
- `restart-daemon` → kill + start
- `reset` → remove scheduled task + delete data dirs

#### Service mode (optional, elevated)

A Windows Service under a dedicated low-privilege account. Uses
`pywin32`'s `win32serviceutil` or a wrapper like NSSM. This is **Phase 2**
of the Windows port — per-user mode ships first.

**Estimated scope:** ~200 lines Python + ~150 lines JS for per-user mode.
Service mode is a separate milestone.

### 5.4 Packaging (W4)

**Scope:** `package.json` + `packaging/win/`

Add to `package.json`:

```json
"win": {
  "target": "nsis",
  "icon": "build/icons/icon.ico"
},
"nsis": {
  "oneClick": false,
  "perMachine": false,
  "allowToChangeInstallationDirectory": true
}
```

Add a `packaging/win/` directory with:
- Icon in `.ico` format
- Optional: Authenticode signing script (Phase 13.9)

The `dist` script gets a platform flag:
`"dist:win": "npm run sync-ui && electron-builder --win nsis"`

Python node on Windows: **bundled with the Electron app** or installed
separately. The simplest path is embedding Python via `python-embed` (the
official embeddable zip from python.org) and installing meshbay-node into
it. This avoids requiring a system Python install.

**Estimated scope:** config + build script, no code changes.

### 5.5 File permissions (W5)

**Scope:** scattered, mechanical

Guard all `chmod` calls:

```python
if sys.platform != "win32":
    path.chmod(0o600)
```

For `keystore.py:97` — skip the mode check on Windows:

```python
if sys.platform != "win32":
    mode = oct(key_file.stat().st_mode)[-3:]
    if mode != "600":
        log.warning(...)
```

For JS `{ mode: 0o600 }` — harmless on Windows (Node.js ignores it on
NTFS), leave as-is.

**Estimated scope:** ~10 lines, trivial guards.

### 5.6 ffmpeg discovery (W6)

**Scope:** `config.py` + `daemon.py` startup

Add to `node.toml`:
```toml
[node]
# ffmpeg_path = "ffmpeg"    # default: found via PATH
```

At daemon startup, resolve with `shutil.which(cfg.ffmpeg_path)` and fail
with a clear message if not found. Pass the resolved path to every
subprocess call.

On Windows, recommend installing ffmpeg via winget (`winget install ffmpeg`)
or bundling it with the installer.

**Estimated scope:** ~30 lines + plumbing the resolved path.

### 5.7 CLI messages (W7)

**Scope:** `daemon.py`, `config.py`

Platform-conditional output in `init`, example configs with Windows paths
when `sys.platform == "win32"`.

**Estimated scope:** ~20 lines, cosmetic.

---

## 6. Execution order

```
W1  Platform directories     ← unblocks everything; testable on Linux
W2  Signal handling           ← 10 lines; do it with W1
W5  File permissions          ← trivial guards; do it with W1
W7  CLI messages              ← cosmetic; do it with W1
W6  ffmpeg discovery          ← small; do it with W1
    ──── milestone: daemon runs on Windows ────
W3  Daemon lifecycle          ← largest item; per-user mode first
    ──── milestone: daemon starts/stops on Windows ────
W4  Packaging                 ← electron-builder config + build script
    ──── milestone: installable on Windows ────
    Service mode (W3b)        ← Phase 2, optional
    Authenticode signing      ← Phase 13.9
    CI Windows matrix         ← Phase 18.3
```

W1 through W7 (minus W3 and W4) can ship as a **single commit** — they are
mechanical, self-contained, and testable on Linux. W3 and W4 are the real
work and can be developed in parallel.

---

## 7. Testing strategy

### What can be tested on Linux

- **Platform directories:** mock `sys.platform` and `os.environ`, verify
  the returned paths match `%LOCALAPPDATA%` layout.
- **Signal handling:** the guard itself (`sys.platform` branch) is testable;
  the actual Windows signal behavior needs a Windows run.
- **File permissions:** verify the `chmod` calls are skipped when
  `sys.platform == "win32"` is mocked.
- **ffmpeg discovery:** mock `shutil.which` returning `None`, verify the
  startup error.
- **CLI messages:** snapshot test the output with mocked platform.
- **Path construction:** `test_paths.py` already covers Windows rules.

### What needs the Windows VM

- **Integration:** daemon startup, WebRTC connection, file indexing on NTFS,
  video streaming with ffmpeg, upload/download cycle.
- **Removable media:** plug/unplug a USB drive, verify the per-root
  unavailable state and the `ReadDirectoryChangesW` watcher recovery.
- **Packaging:** build the NSIS installer, install, verify file placement,
  verify `safeStorage`/DPAPI works, verify Task Scheduler autostart.
- **Electron:** visual check of the UI, native save dialog, node management
  panel (once W3 is done).
- **Long paths:** a library with a path exceeding 260 characters on NTFS
  with long paths enabled.
- **Case collisions:** a group indexed on ext4 containing `Film.mkv` and
  `film.mkv`, opened from a Windows client.

### CI (future, Phase 18.3)

Add a Windows runner to GitHub Actions:
- `pytest` on Windows with a real NTFS filesystem
- Electron build for Windows
- The filesystem portability tests from `test_paths.py` run natively
  rather than via mock

---

## 8. Dependencies and prerequisites

| Dependency | Linux | Windows |
|---|---|---|
| Python 3.12+ | system / venv | `python-embed` zip or full install |
| ffmpeg / ffprobe | system package | `winget install ffmpeg` or bundled |
| Node.js 22+ | `/opt/nodejs` | installer from nodejs.org |
| Electron 42+ | npm | npm (same) |
| aiortc | pip | pip (same — pure Python) |
| watchdog | pip | pip (same — uses `ReadDirectoryChangesW`) |
| Argon2 WASM | vendored in `static/vendor/` | same |
| safeStorage backend | libsecret / kwallet | DPAPI (built into Windows) |

No new Python dependency is needed for per-user mode. Service mode (W3b)
would need `pywin32` or NSSM.

---

## 9. What is NOT in scope

- **The hub** — stays Linux. No Windows port planned or needed.
- **macOS** — not planned. `safeStorage` already handles darwin, but no
  packaging, no daemon lifecycle, no testing.
- **Windows ARM** — not considered. Electron supports it; Python and
  ffmpeg availability would need checking.
- **Windows Store / MSIX** — not planned for v1. NSIS per-user installer
  is the target.
- **Service mode** — Phase 2 of the Windows port, after per-user mode is
  validated.