add FCE config validation

Cargo.lock

@@ -130,6 +130,12 @@ dependencies = [
  "digest 0.9.0",
 ]
 
+[[package]]
+name = "boolinator"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfa8873f51c92e232f9bac4065cddef41b714152812bfc5f7672ba16d6ef8cd9"
+
 [[package]]
 name = "byteorder"
 version = "1.3.4"
@@ -443,6 +449,7 @@ dependencies = [
 name = "fce"
 version = "0.1.0"
 dependencies = [
+ "boolinator",
  "fce-wit-interfaces",
  "fce-wit-parser",
  "log",

engine/Cargo.toml

@@ -22,6 +22,7 @@ wasmer-wasi = { package = "wasmer-wasi-fl", version = "0.17.0" }
 serde = { version = "1.0.114", default-features = false, features = [ "derive" ] }
 
 multimap = "0.8.1"
+boolinator = "2.4.0"
 parity-wasm = "0.41.0"
 pwasm-utils = "0.12.0"
 log = "0.4.8"

engine/src/engine.rs

@@ -80,6 +80,7 @@ impl FCE {
         wasm_bytes: &[u8],
         config: FCEModuleConfig,
     ) -> Result<()> {
+        Self::validate_config(&config)?;
         let _prepared_wasm_bytes = crate::misc::prepare_module(wasm_bytes, config.mem_pages_count)?;
 
         let module = FCEModule::new(&wasm_bytes, config, &self.modules)?;
@@ -136,6 +137,43 @@ impl FCE {
             })
             .collect::<Vec<_>>()
     }
+
+    #[rustfmt::skip]
+    fn validate_config(config: &FCEModuleConfig) -> Result<()> {
+        use boolinator::Boolinator;
+
+        fn has_only_unique_elements<T>(mut iter: T) -> bool
+        where
+            T: Iterator,
+            T::Item: Eq + std::hash::Hash,
+        {
+            let mut uniq = std::collections::HashSet::new();
+            iter.all(move |x| uniq.insert(x))
+        }
+
+        has_only_unique_elements(config.wasi_envs.iter()).as_result(
+            (),
+            FCEError::InvalidConfig(String::from(
+                "Supplied config contains environment variable with the same names",
+            )),
+        )?;
+
+        has_only_unique_elements(config.wasi_mapped_dirs.iter().map(|(alias, _)| alias)).as_result(
+            (),
+            FCEError::InvalidConfig(String::from(
+                "Supplied config contains mapped dirs with the same aliases",
+            )),
+        )?;
+
+        has_only_unique_elements(config.wasi_preopened_files.iter()).as_result(
+            (),
+            FCEError::InvalidConfig(String::from(
+                "Supplied config contains preopened files with the same file names",
+            )),
+        )?;
+
+        Ok(())
+    }
 }
 
 impl Default for FCE {

engine/src/errors.rs

@@ -55,6 +55,9 @@ pub enum FCEError {
 
     /// Incorrect WIT section.
     IncorrectWIT(String),
+
+    /// Invalid FCE config (such as duplicated envs, preopened_files or mapped_dirs).
+    InvalidConfig(String),
 }
 
 impl Error for FCEError {}
@@ -78,6 +81,7 @@ impl std::fmt::Display for FCEError {
             }
             FCEError::WITParseError(err) => write!(f, "{}", err),
             FCEError::IncorrectWIT(err_msg) => write!(f, "{}", err_msg),
+            FCEError::InvalidConfig(err_msg) => write!(f, "{}", err_msg),
         }
     }
 }

engine/src/module/fce_module.rs

@@ -86,7 +86,7 @@ pub(crate) struct FCEModule {
 impl FCEModule {
     pub(crate) fn new(
         wasm_bytes: &[u8],
-        fce_module_config: FCEModuleConfig,
+        config: FCEModuleConfig,
         modules: &HashMap<String, FCEModule>,
     ) -> Result<Self> {
         let wasmer_module = compile(&wasm_bytes)?;
@@ -97,15 +97,15 @@ impl FCEModule {
         let import_object = Self::adjust_wit_imports(&fce_wit, wit_instance.clone())?;
 
         let mut wasi_import_object = wasmer_wasi::generate_import_object_for_version(
-            fce_module_config.wasi_version,
+            config.wasi_version,
             vec![],
-            fce_module_config.wasi_envs.clone(),
-            fce_module_config.wasi_preopened_files.clone(),
-            fce_module_config.wasi_mapped_dirs.clone(),
+            config.wasi_envs.clone(),
+            config.wasi_preopened_files.clone(),
+            config.wasi_mapped_dirs.clone(),
         );
 
         wasi_import_object.extend(import_object.clone());
-        wasi_import_object.extend(fce_module_config.imports.clone());
+        wasi_import_object.extend(config.imports.clone());
 
         let wasmer_instance = wasmer_module.instantiate(&wasi_import_object)?;
         let wit_instance = unsafe {
@@ -127,7 +127,7 @@ impl FCEModule {
         Ok(Self {
             wasmer_instance: Box::new(wasmer_instance),
             import_object,
-            host_import_object: fce_module_config.imports,
+            host_import_object: config.imports,
             exports_funcs,
         })
     }