From f20de9b925f9ade6ff5fecd34a04fa18acf13d3d Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Fri, 1 Nov 2024 20:25:17 +0000
Subject: [PATCH] test: Add `tools/symbol-check.py`

Co-authored-by: Tim Ruffing <crypto@timruffing.de>
---
 tools/symbol-check.py | 72 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100755 tools/symbol-check.py

diff --git a/tools/symbol-check.py b/tools/symbol-check.py
new file mode 100755
index 0000000000..d359fd52b4
--- /dev/null
+++ b/tools/symbol-check.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""Check that a libsecp256k1 shared library exports only expected symbols.
+
+Usage examples:
+  - When building with Autotools:
+    ./tools/symbol-check.py .libs/libsecp256k1.so
+    ./tools/symbol-check.py .libs/libsecp256k1-<V>.dll
+    ./tools/symbol-check.py .libs/libsecp256k1.dylib
+
+  - When building with CMake:
+    ./tools/symbol-check.py build/lib/libsecp256k1.so
+    ./tools/symbol-check.py build/bin/libsecp256k1-<V>.dll
+    ./tools/symbol-check.py build/lib/libsecp256k1.dylib"""
+
+import re
+import sys
+import subprocess
+
+import lief
+
+
+class UnexpectedExport(RuntimeError):
+    pass
+
+
+def get_exported_exports(library) -> list[str]:
+    """Adapter function to get exported symbols based on the library format."""
+    if library.format == lief.Binary.FORMATS.ELF:
+        return [symbol.name for symbol in library.exported_symbols]
+    elif library.format == lief.Binary.FORMATS.PE:
+        return [entry.name for entry in library.get_export().entries]
+    elif library.format == lief.Binary.FORMATS.MACHO:
+        return [symbol.name[1:] for symbol in library.exported_symbols]
+    raise NotImplementedError(f"Unsupported format: {library.format}")
+
+
+def grep_expected_symbols() -> list[str]:
+    """Guess the list of expected exported symbols from the source code."""
+    grep_output = subprocess.check_output(
+        ["git", "grep", "^SECP256K1_API", "--", "include"], # TODO WHITESPACE
+        universal_newlines=True,
+        encoding="utf-8"
+    )
+    lines = grep_output.split("\n")
+    pattern = re.compile(r'\bsecp256k1_\w+')
+    exported: list[str] = [pattern.findall(line)[-1] for line in lines if line.strip()]
+    return exported
+
+
+def check_symbols(library, expected_exports) -> None:
+    """Check that the library exports only the expected symbols."""
+    actual_exports = list(get_exported_exports(library))
+    unexpected_exports = set(actual_exports) - set(expected_exports)
+    if unexpected_exports != set():
+        raise UnexpectedExport(f"Unexpected exported symbols: {unexpected_exports}")
+
+def main():
+    if len(sys.argv) != 2:
+        print(__doc__)
+        return 1
+    library = lief.parse(sys.argv[1])
+    expected_exports = grep_expected_symbols()
+    try:
+        check_symbols(library, expected_exports)
+    except UnexpectedExport as e:
+        print(f"{sys.argv[0]}: In {sys.argv[1]}: {e}")
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())