ci: Only pass documented env vars

ci/test/02_run_container.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+# Copyright (c) The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+import os
+import shlex
+import subprocess
+import sys
+
+
+def run(cmd, **kwargs):
+    print("+ " + shlex.join(cmd), flush=True)
+    try:
+        return subprocess.run(cmd, check=True, **kwargs)
+    except Exception as e:
+        sys.exit(e)
+
+
+def main():
+    print("Export only allowed settings:")
+    settings = run(
+        ["bash", "-c", "grep export ./ci/test/00_setup_env*.sh"],
+        stdout=subprocess.PIPE,
+        text=True,
+        encoding="utf8",
+    ).stdout.splitlines()
+    settings = set(l.split("=")[0].split("export ")[1] for l in settings)
+    # Add this one manually, because it is the only one set inside the
+    # container that also allows external overwrites
+    settings.add("BASE_BUILD_DIR")
+
+    # Append $USER to /tmp/env to support multi-user systems and $CONTAINER_NAME
+    # to allow support starting multiple runs simultaneously by the same user.
+    env_file = "/tmp/env-{u}-{c}".format(
+        u=os.getenv("USER"),
+        c=os.getenv("CONTAINER_NAME"),
+    )
+    with open(env_file, "w", encoding="utf8") as file:
+        for k, v in os.environ.items():
+            if k in settings:
+                file.write(f"{k}={v}\n")
+    run(["cat", env_file])
+
+    run(["./ci/test/02_run_container.sh"])  # run the remainder
+
+
+if __name__ == "__main__":
+    main()