feat: Read version information in Wasm Module

src/libxrpl/tx/wasm/WasmiVM.cpp

@@ -799,6 +799,98 @@ WasmiEngine::run(
     return Unexpected<TER>(tecFAILED_PROCESSING);
 }
 
+namespace {
+
+struct CustomSection
+{
+    std::string_view name;
+    std::span<uint8_t const> payload;
+};
+
+struct Version
+{
+    std::string_view name;
+    std::string_view version;
+};
+
+uint32_t
+readLEB128(Bytes const& wasmCode, size_t& offset)
+{
+    auto result = uint32_t{};
+    auto shift = uint32_t{};
+    while (true)
+    {
+        auto byte = wasmCode[offset++];
+        result |= (byte & 0x7F) << shift;
+        if ((byte & 0x80) == 0)
+        {
+            break;
+        }
+        shift += 7;
+    }
+    return result;
+}
+
+template <typename Filter>
+void
+filterCustomSections(Bytes const& wasmCode, Filter&& filter)
+{
+    auto offset = size_t{8};  // Skip Magic number and Version
+
+    while (offset < wasmCode.size())
+    {
+        auto sectionId = wasmCode[offset++];
+        auto sectionSize = readLEB128(wasmCode, offset);
+        auto nextSection = offset + sectionSize;
+
+        if (sectionId == 0)
+        {
+            auto customSection = CustomSection{};
+
+            auto size = readLEB128(wasmCode, offset);
+            customSection.name =
+                std::string_view{reinterpret_cast<char const*>(wasmCode.data()) + offset, size};
+            offset += size;
+
+            size = nextSection - offset;
+            customSection.payload = std::span<uint8_t const>{
+                reinterpret_cast<uint8_t const*>(wasmCode.data()) + offset, size};
+
+            if (filter(customSection))
+            {
+                return;
+            }
+        }
+        offset = nextSection;
+    }
+}
+
+std::vector<Version>
+extractVersionInfo(Bytes const& wasmCode)
+{
+    static constexpr auto kCommonLib = "xrpl-common-stdlib";
+    static constexpr auto kEscrowLib = "xrpl-escrow-stdlib";
+
+    auto versions = std::vector<Version>{};
+    filterCustomSections(wasmCode, [&](auto const& section) {
+        if (section.name == kCommonLib || section.name == kEscrowLib)
+        {
+            versions.emplace_back(
+                Version{
+                    .name = section.name,
+                    .version = std::string_view{
+                        reinterpret_cast<char const*>(section.payload.data()),
+                        section.payload.size()}});
+        }
+
+        // Just read until we have found all the information we are looking for.
+        return versions.size() == 2;
+    });
+    return versions;
+}
+
+}  // namespace
+
 Expected<WasmResult<int32_t>, TER>
 WasmiEngine::runHlp(
     Bytes const& wasmCode,
@@ -818,6 +910,13 @@ WasmiEngine::runHlp(
     if (!hfs.checkSelf())
         throw std::runtime_error("hfs isn't clean");
 
+    auto versionInfo = extractVersionInfo(wasmCode);
+
+    for (auto const& version : versionInfo)
+    {
+        std::cout << version.name << " " << version.version << "\n";
+    }
+
     // Create and instantiate the module.
     [[maybe_unused]] int const m = addModule(wasmCode, true, imports, gas);
 

src/test/app/Wasm_test.cpp

@@ -227,6 +227,26 @@ struct Wasm_test : public beast::unit_test::Suite
         checkResult(re, 6'912, 59);
     }
 
+    void
+    testVersion()
+    {
+        testcase("wasm lib test");
+        static auto const kWasmModule = hexToBytes(
+            "0061736d010000000105016000017f03020100040401700000070a010666696e69736800000a0601040041"
+            "010b0018127872706c2d657363726f772d7374646c6962342e352e360018127872706c2d636f6d6d6f6e2d"
+            "7374646c6962312e322e33");
+
+        auto& vm = WasmEngine::instance();
+
+        HostFunctions hfs;
+        ImportVec imports;
+        WasmImpFunc<Add_proto>(imports, "func-add", reinterpret_cast<void*>(&add), &hfs);
+
+        auto re = vm.run(kWasmModule, hfs, 10'000'000, "finish", wasmParams(1234), imports);
+
+        checkResult(re, 1, 59);
+    }
+
     void
     testBadWasm()
     {
@@ -1549,6 +1569,8 @@ struct Wasm_test : public beast::unit_test::Suite
     {
         using namespace test::jtx;
 
+        testVersion();
+
         testGetDataHelperFunctions();
         testWasmLib();
         testBadWasm();

src/test/app/wasm_fixtures/wat/custom_version.wat

@@ -0,0 +1,13 @@
+(module
+  ;; Define a table with exactly 0 entries
+  (table 0 funcref)
+
+  ;; Standard finish function
+  (func $finish (result i32)
+    i32.const 1
+  )
+  (export "finish" (func $finish))
+
+  (@custom "xrpl-escrow-stdlib" "4.5.6")
+  (@custom "xrpl-common-stdlib" "1.2.3")
+)