From d589d7e01878cca6954823945acddbaa6dc75f2d Mon Sep 17 00:00:00 2001
From: Andri Saar <andrisaar@google.com>
Date: Tue, 13 Feb 2024 14:36:48 +0000
Subject: [PATCH] Reduce the number of exported symbols from the native lookup
 library

---
 cc/native_sdk/BUILD          | 2 ++
 cc/native_sdk/native_sdk.h   | 2 +-
 cc/native_sdk/symbols.map.ld | 7 +++++++
 3 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 cc/native_sdk/symbols.map.ld

diff --git a/cc/native_sdk/BUILD b/cc/native_sdk/BUILD
index a6bd2afcbc8..a8835f2b27f 100644
--- a/cc/native_sdk/BUILD
+++ b/cc/native_sdk/BUILD
@@ -36,8 +36,10 @@ cc_library(
 cc_binary(
     name = "key_value_lookup",
     srcs = ["key_value_lookup.cc"],
+    linkopts = ["-Wl,--version-script,$(location symbols.map.ld)"],
     linkshared = True,
     deps = [
+        "symbols.map.ld",
         ":native_sdk",
         "@com_google_absl//absl/log:check",
     ],
diff --git a/cc/native_sdk/native_sdk.h b/cc/native_sdk/native_sdk.h
index 2d88be56193..f98b622a595 100644
--- a/cc/native_sdk/native_sdk.h
+++ b/cc/native_sdk/native_sdk.h
@@ -26,7 +26,7 @@
 // We call oak_main without arguments, and oak_main then calls read_request,
 // processes the request, and then calls write_response.  This makes the API
 // compatible with Oak Functions.
-#define OAK_MAIN void oak_main()
+#define OAK_MAIN extern "C" void oak_main()
 
 namespace oak::functions::sdk {
 
diff --git a/cc/native_sdk/symbols.map.ld b/cc/native_sdk/symbols.map.ld
new file mode 100644
index 00000000000..c67a82a81d7
--- /dev/null
+++ b/cc/native_sdk/symbols.map.ld
@@ -0,0 +1,7 @@
+{
+    global:
+        register_callbacks;
+        oak_main;
+    local:
+        *;
+};