Function sc_executor::read_embedded_version

pub fn read_embedded_version(
    blob: &RuntimeBlob
) -> Result<Option<RuntimeVersion>, WasmError>

Take the runtime blob and scan it for the custom wasm sections containing the version information and construct the RuntimeVersion from them.

If there are no such sections, it returns None. If there is an error during decoding those sections, Err will be returned.

Examples found in repository

src/native_executor.rs (line 298)

	fn read_runtime_version(
		&self,
		wasm_code: &[u8],
		ext: &mut dyn Externalities,
	) -> std::result::Result<Vec<u8>, String> {
		let runtime_blob = RuntimeBlob::uncompress_if_needed(wasm_code)
			.map_err(|e| format!("Failed to create runtime blob: {:?}", e))?;

		if let Some(version) = crate::wasm_runtime::read_embedded_version(&runtime_blob)
			.map_err(|e| format!("Failed to read the static section: {:?}", e))
			.map(|v| v.map(|v| v.encode()))?
		{
			return Ok(version)
		}

		// If the blob didn't have embedded runtime version section, we fallback to the legacy
		// way of fetching the version: i.e. instantiating the given instance and calling
		// `Core_version` on it.

		self.uncached_call(
			runtime_blob,
			ext,
			// If a runtime upgrade introduces new host functions that are not provided by
			// the node, we should not fail at instantiation. Otherwise nodes that are
			// updated could run this successfully and it could lead to a storage root
			// mismatch when importing this block.
			true,
			"Core_version",
			&[],
		)
		.map_err(|e| e.to_string())
	}

src/wasm_runtime.rs (line 411)

fn create_versioned_wasm_runtime<H>(
	code: &[u8],
	ext: &mut dyn Externalities,
	wasm_method: WasmExecutionMethod,
	heap_pages: u64,
	allow_missing_func_imports: bool,
	max_instances: usize,
	cache_path: Option<&Path>,
) -> Result<VersionedRuntime, WasmError>
where
	H: HostFunctions,
{
	// The incoming code may be actually compressed. We decompress it here and then work with
	// the uncompressed code from now on.
	let blob = sc_executor_common::runtime_blob::RuntimeBlob::uncompress_if_needed(code)?;

	// Use the runtime blob to scan if there is any metadata embedded into the wasm binary
	// pertaining to runtime version. We do it before consuming the runtime blob for creating the
	// runtime.
	let mut version: Option<_> = read_embedded_version(&blob)?;

	let runtime = create_wasm_runtime_with_code::<H>(
		wasm_method,
		heap_pages,
		blob,
		allow_missing_func_imports,
		cache_path,
	)?;

	// If the runtime blob doesn't embed the runtime version then use the legacy version query
	// mechanism: call the runtime.
	if version.is_none() {
		// Call to determine runtime version.
		let version_result = {
			// `ext` is already implicitly handled as unwind safe, as we store it in a global
			// variable.
			let mut ext = AssertUnwindSafe(ext);

			// The following unwind safety assertion is OK because if the method call panics, the
			// runtime will be dropped.
			let runtime = AssertUnwindSafe(runtime.as_ref());
			crate::native_executor::with_externalities_safe(&mut **ext, move || {
				runtime.new_instance()?.call("Core_version".into(), &[])
			})
			.map_err(|_| WasmError::Instantiation("panic in call to get runtime version".into()))?
		};

		if let Ok(version_buf) = version_result {
			version = Some(decode_version(&version_buf)?)
		}
	}

	let mut instances = Vec::with_capacity(max_instances);
	instances.resize_with(max_instances, || Mutex::new(None));

	Ok(VersionedRuntime { module: runtime, version, instances: Arc::new(instances) })
}