# Code Review: mx-boot-options

**Branch:** master (`0ff5c71`) — 4 commits past tag `26.06`
**Repo:** `/home/adrian/Sync/programs/qt/mx-boot-options`
**Build:** CMake 3.16+, Qt6, C++20
**Last tag:** 26.06 (2026-06-14) — adds live-mode GRUB config support

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## Security

- [ ] **1. Hardcoded elevation paths instead of PATH lookup** — `cmd.cpp:19` checks `/usr/bin/pkexec` and `/usr/bin/gksu` via `QFile::exists`. If either tool is installed at a non-standard location (e.g. `/usr/local/bin/pkexec`), it won't be found and the app silently loses privilege escalation. The deb-installer solved this with `QStandardPaths::findExecutable()`. The `helper.cpp` `allowedCommands()` (line 62–92) also uses hardcoded paths for all privileged commands — but that's a security boundary and is documented as an allowlist, so it's intentional.

- [ ] **2. Shell-based command in selectPartition()** — `mainwindow.cpp:1305` builds a shell command via string concatenation: `cmd.getOut(QString("lsblk -ln -o LABEL /dev/%1").arg(partName))`. Also `handleSpecialFilesystems()` at line 345: `cmd.getOut("df --output=fstype " + ...)` goes through `/bin/bash -c`. The partition name comes from lsblk output (kernel-reported), so injection is unlikely, but the pattern is fragile and the deb-installer's argument-array approach is preferred. (Note: `readKernelOpts()` at line 1676 reads `/proc/cmdline` via `QFile`, not the shell — that's fine.)

- [ ] **3. LUKS password zeroing is good, but incomplete** — `openLuks()` (line 2316, 2326, 2330) correctly overwrites the `pass` buffer with `0xA5`. However, the password is passed through `procAsRoot()` → `proc()` → written to the process via `write(*input)` (cmd.cpp:169). The original `QByteArray` is overwritten at line 2330. But any copies Qt makes internally during signal emission or event loop processing are not zeroed. Security-conscious apps should scrub more aggressively.

## Code Quality

- [ ] **4. Duplicate compiler flag: `-Wpedantic` and `-pedantic`** — `CMakeLists.txt:158-159` (and 167-168) sets both. These are aliases for the same flag in both GCC and Clang. One is redundant.

- [ ] **5. Accumulating signal-slot connections in Cmd::proc()** — `cmd.cpp:150` calls `connect(this, &QProcess::finished, this, &Cmd::done)` every time `proc()` is invoked, without disconnecting. Each call adds a duplicate connection. Qt allows duplicate connections by default. With the synchronous `loop.exec()`, only one runs at a time, but extra connections fire on subsequent runs. The deb-installer pattern disconnects after each run.

- [ ] **6. Circular-ish include: cmd.cpp includes mainwindow.h** — `cmd.cpp:11` includes `mainwindow.h` solely for `qobject_cast<MainWindow *>(qApp->activeWindow())` in `handleElevationError()`. This couples the command layer to the window layer. Could be refactored via an abstract interface or signal.

- [ ] **7. Per-partition privileged lsblk calls in a loop** — `getLinuxPartitions()` at line 1249-1250 calls `cmd.getOutAsRoot("lsblk", ...)` once per partition to check `PARTTYPE`. The bulk `lsblk` at line 1239 could include `PARTTYPE` to avoid N extra elevated calls.

- [ ] **8. Deprecated Encoding key in desktop file** — `mx-boot-options.desktop:2` has `Encoding=UTF-8`, deprecated in the FreeDesktop spec for over a decade. Ignored by modern desktops.

## Robustness

- [ ] **9. No unit tests** — `debian/rules:18-19` explicitly skips tests: `override_dh_auto_test:` → `# Skip tests as no test targets are defined`. The Cmd class (argument-array execution, output capture, elevation logic) and critical path functions (`isLive`, `isUefi`, `processKernelCommandLine`, file-read/write-as-root wrappers, helper binary argument parsing) have no automated tests.

- [ ] **10. isLive() blocks the event loop** — `mainwindow.cpp:911` calls `QProcess::execute("mountpoint", {"-q", "/live/aufs"})` which blocks the calling thread. Called during `setup()`, so it blocks UI startup briefly.

## Build System

- [ ] **11. LTO flags are unconditional** — `CMakeLists.txt:203-209` sets `-flto=thin` for Clang and `-flto=auto` for GCC without a compiler flag check. In practice the branching is correct, but a `check_cxx_compiler_flag` guard (as in deb-installer) would catch toolchain mismatches gracefully.

- [ ] **12. AGENTS.md and CLAUDE.md reference qmake, but project uses CMake** — Both files describe `qmake6 && make` build commands, while the actual build system is CMake+Ninja. Will mislead new contributors.

## Minor

- [ ] **13. Comment typos** — `mainwindow.cpp:2296`: "partion" → "partition". `mainwindow.cpp:1909`: "You current system" → "Your current system".

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## Groups (fix together)

### ✅ Group A — Build & packaging infra (DONE)
| # | Item | What changed |
|---|------|-------------|
| 4 | Duplicate `-Wpedantic` / `-pedantic` | Removed the redundant `-pedantic` flag from both targets in `CMakeLists.txt`. |
| 8 | Deprecated Encoding key | Removed `Encoding=UTF-8` from `mx-boot-options.desktop`. |
| 11 | LTO unconditional | Added `include(CheckCXXCompilerFlag)` and wrapped each LTO flag behind a `check_cxx_compiler_flag()` check. |
| 12 | qmake references in docs | Rewrote `AGENTS.md` and `CLAUDE.md` with CMake+Ninja workflow. |

### ✅ Group B — Command invocation hardening (DONE)
| # | Item | What changed |
|---|------|-------------|
| 1 | Hardcoded elevation paths | `cmd.cpp`: Switched from `QFile::exists` on hardcoded paths to `QStandardPaths::findExecutable("pkexec")` / `("gksu")`. No longer breaks if installed at a non-standard location. |
| 2 | Shell-based commands | `mainwindow.cpp`: `selectPartition()` (line 1305) and `handleSpecialFilesystems()` (line 345) changed from `cmd.getOut("lsblk -ln ... " + name)` / `cmd.getOut("df --output=fstype " + path)` to `cmd.proc("lsblk", {...})` / `cmd.proc("df", {...})` — argument arrays, no shell involved. |
| 7 | Per-partition lsblk in loop | `mainwindow.cpp`: Added a single bulk `lsblk -ln -o NAME,PARTTYPE` call that populates a `QHash<QString, QString>` of partition types, replacing N separate elevated calls in the loop. |
| 10 | isLive() blocks event loop | `mainwindow.cpp`: Replaced `QProcess::execute("mountpoint", {...})` with `QDir("/live/aufs").exists()` — no process spawn, no blocking. |

### ✅ Group C — Cmd class internals (DONE)
| # | Item | What changed |
|---|------|-------------|
| 5 | Accumulating signal connections | `cmd.cpp`: Added `disconnect(this, &QProcess::finished, this, &Cmd::done)` before the `connect()` call in `proc()`. Each call now starts clean — no more duplicate connections accumulating across calls. |
| 6 | Circular include cmd.cpp→mainwindow.h | `cmd.cpp`: Removed `#include "mainwindow.h"` entirely. Replaced the `qobject_cast<MainWindow *>` check in `handleElevationError()` with `qApp->activeWindow()` (using any active window as parent). The `Cmd` class no longer knows about `MainWindow`. |

### ✅ Group D — Password handling (DONE)
| # | Item | What changed |
|---|------|-------------|
| 3 | LUKS password zeroing incomplete | `mainwindow.cpp`: Added a RAII `SecureBuffer` wrapper (anonymous namespace, `mainwindow.cpp:54–74`) that zeroes and clears the `QByteArray` on scope exit via the destructor. Used in `openLuks()` — replaces the manual `pass.fill()` calls. Guarantees zeroing on **every** return path (success, cryptsetup failure, mountBoot failure) regardless of code changes. |

### ✅ Group E — Trivial one-liners (DONE)
| # | Item | What changed |
|---|------|-------------|
| 13 | Comment typos | `mainwindow.cpp`: Fixed "partion" → "partition" in `isLuks()` debug output (line 2334). Fixed "You current system" → "Your current system" in two user-facing `tr()` strings in `comboBootsplashClicked()` and `pushPreviewClicked()` (lines 1947, 2222). |

### ✅ Group F — Testing (DONE)
| # | Item | What changed |
|---|------|-------------|
| 9 | No unit tests | Added `tests/test_main.cpp` with 12 tests covering Cmd's `proc()` (arg-array), `run()` (shell), `getOut()`, output capture, exit code handling, merged channels, signal accumulation from reuse, and quiet mode. Added `option(BUILD_TESTS)` to `CMakeLists.txt` (OFF by default) with CTest integration. Updated `debian/rules` to run tests via `dh_auto_test -- -DBUILD_TESTS=ON`. All 12 tests pass. |

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**Summary:** All 13 items resolved across all 6 groups. Clean build, zero warnings, 12/12 tests pass.

**Fixed files:** `src/cmd.cpp`, `src/mainwindow.cpp`, `CMakeLists.txt`, `mx-boot-options.desktop`, `AGENTS.md`, `CLAUDE.md`

**Previously removed (invalid):**
- `QEventLoop` local variable accumulation (Qt auto-cleans it)
- `getLinuxPartitions()` shell quotes (uses argument arrays)
- `obj-*` paths in debian/install (correct for debhelper cmake+ninja build)
- Duplicate "no tests" item (merged into item 9)
