feat: create firmware skeleton and reproducible build

scripts/reproducible_mklittlefs.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+"""Run mklittlefs with a fixed wall clock for reproducible images."""
+
+from __future__ import annotations
+
+import os
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+
+def build_time_override(output_path: Path) -> None:
+    source_path = Path(__file__).with_name("reproducible_time.c")
+    compiler = shutil.which("cc")
+    if compiler is None:
+        raise RuntimeError("A host C compiler named 'cc' is required")
+    subprocess.run(
+        [
+            compiler,
+            "-shared",
+            "-fPIC",
+            "-O2",
+            str(source_path),
+            "-o",
+            str(output_path),
+        ],
+        check=True,
+    )
+
+
+def main() -> int:
+    real_tool = os.environ.get("MAZE32_REAL_MKFSTOOL")
+    build_directory = os.environ.get("MAZE32_BUILD_DIR")
+    if not real_tool or not build_directory:
+        raise RuntimeError("PlatformIO did not provide the filesystem tool environment")
+
+    override_path = Path(build_directory) / "reproducible_time.so"
+    override_path.parent.mkdir(parents=True, exist_ok=True)
+    build_time_override(override_path)
+
+    environment = os.environ.copy()
+    existing_preload = environment.get("LD_PRELOAD")
+    environment["LD_PRELOAD"] = (
+        f"{override_path}:{existing_preload}" if existing_preload else str(override_path)
+    )
+    completed = subprocess.run([real_tool, *sys.argv[1:]], env=environment)
+    return completed.returncode
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())