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fix(c-api) Fix memory leak and owernship in WASI.

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In `wasi_get_imports` and `wasi_get_unordered_imports`, we said the
ownership of `wasi_env_t` was taken by the function, but it wasn't the
case. This patch changes the type from `&wasi_env_t` to
`Box<wasi_env_t>` to take ownership of it.

The rest of the patch updates the documentation, and improves null
protections with `Option<T>`.
This commit is contained in:
Ivan Enderlin
2021-02-01 14:55:45 +01:00
parent b1dc0416dd
commit 9e63ba9a25
1 changed files with 47 additions and 21 deletions
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68
lib/c-api/src/wasm_c_api/wasi/mod.rs
View File

@@ -171,7 +171,9 @@ pub struct wasi_env_t {
inner: WasiEnv,
}
/// Takes ownership over the `wasi_config_t`.
/// Create a new WASI environment.
///
/// It take ownership over the `wasi_config_t`.
#[no_mangle]
pub extern "C" fn wasi_env_new(mut config: Box<wasi_config_t>) -> Option<Box<wasi_env_t>> {
if !config.inherit_stdout {
@@ -195,6 +197,7 @@ pub extern "C" fn wasi_env_new(mut config: Box<wasi_config_t>) -> Option<Box<was
}))
}
/// Delete a [`wasi_env_t`].
#[no_mangle]
pub extern "C" fn wasi_env_delete(_state: Option<Box<wasi_env_t>>) {}
@@ -346,6 +349,8 @@ pub unsafe extern "C" fn wasi_get_wasi_version(module: &wasm_module_t) -> wasi_v
/// two `wasm_name_t` respectively for the module name and the name of
/// the extern (very likely to be an import). This non-standard type
/// is used by the non-standard `wasi_get_unordered_imports` function.
///
/// The `module`, `name` and `extern` fields are all owned by this type.
#[allow(non_camel_case_types)]
#[derive(Clone)]
pub struct wasm_named_extern_t {
@@ -358,22 +363,34 @@ wasm_declare_boxed_vec!(named_extern);
/// Non-standard function to get the module name of a
/// `wasm_named_extern_t`.
///
/// The returned value isn't owned by the caller.
#[no_mangle]
pub extern "C" fn wasm_named_extern_module(named_extern: &wasm_named_extern_t) -> &wasm_name_t {
named_extern.module.as_ref()
pub extern "C" fn wasm_named_extern_module(
named_extern: Option<&wasm_named_extern_t>,
) -> Option<&wasm_name_t> {
Some(named_extern?.module.as_ref())
}
/// Non-standard function to get the name of a `wasm_named_extern_t`.
///
/// The returned value isn't owned by the caller.
#[no_mangle]
pub extern "C" fn wasm_named_extern_name(named_extern: &wasm_named_extern_t) -> &wasm_name_t {
named_extern.name.as_ref()
pub extern "C" fn wasm_named_extern_name(
named_extern: Option<&wasm_named_extern_t>,
) -> Option<&wasm_name_t> {
Some(named_extern?.name.as_ref())
}
/// Non-standard function to get the wrapped extern of a
/// `wasm_named_extern_t`.
///
/// The returned value isn't owned by the caller.
#[no_mangle]
pub extern "C" fn wasm_named_extern_unwrap(named_extern: &wasm_named_extern_t) -> &wasm_extern_t {
named_extern.r#extern.as_ref()
pub extern "C" fn wasm_named_extern_unwrap(
named_extern: Option<&wasm_named_extern_t>,
) -> Option<&wasm_extern_t> {
Some(named_extern?.r#extern.as_ref())
}
/// Non-standard function to get the imports needed for the WASI
@@ -384,20 +401,24 @@ pub extern "C" fn wasm_named_extern_unwrap(named_extern: &wasm_named_extern_t) -
/// This function takes ownership of `wasm_env_t`.
#[no_mangle]
pub unsafe extern "C" fn wasi_get_unordered_imports(
store: &wasm_store_t,
module: &wasm_module_t,
wasi_env: &wasi_env_t,
store: Option<&wasm_store_t>,
module: Option<&wasm_module_t>,
wasi_env: Option<Box<wasi_env_t>>,
imports: &mut wasm_named_extern_vec_t,
) -> bool {
wasi_get_unordered_imports_inner(store, module, wasi_env, imports).is_some()
}
unsafe fn wasi_get_unordered_imports_inner(
store: &wasm_store_t,
module: &wasm_module_t,
wasi_env: &wasi_env_t,
store: Option<&wasm_store_t>,
module: Option<&wasm_module_t>,
wasi_env: Option<Box<wasi_env_t>>,
imports: &mut wasm_named_extern_vec_t,
) -> Option<()> {
let store = store?;
let module = module?;
let wasi_env = wasi_env?;
let store = &store.inner;
let version = c_try!(
@@ -436,9 +457,9 @@ unsafe fn wasi_get_unordered_imports_inner(
/// This function takes ownership of `wasm_env_t`.
#[no_mangle]
pub unsafe extern "C" fn wasi_get_imports(
store: &wasm_store_t,
module: &wasm_module_t,
wasi_env: &wasi_env_t,
store: Option<&wasm_store_t>,
module: Option<&wasm_module_t>,
wasi_env: Option<Box<wasi_env_t>>,
imports: &mut wasm_extern_vec_t,
) -> bool {
wasi_get_imports_inner(store, module, wasi_env, imports).is_some()
@@ -446,11 +467,15 @@ pub unsafe extern "C" fn wasi_get_imports(
/// Takes ownership of `wasi_env_t`.
unsafe fn wasi_get_imports_inner(
store: &wasm_store_t,
module: &wasm_module_t,
wasi_env: &wasi_env_t,
store: Option<&wasm_store_t>,
module: Option<&wasm_module_t>,
wasi_env: Option<Box<wasi_env_t>>,
imports: &mut wasm_extern_vec_t,
) -> Option<()> {
let store = store?;
let module = module?;
let wasi_env = wasi_env?;
let store = &store.inner;
let version = c_try!(
@@ -491,9 +516,10 @@ unsafe fn wasi_get_imports_inner(
pub unsafe extern "C" fn wasi_get_start_function(
instance: &mut wasm_instance_t,
) -> Option<Box<wasm_func_t>> {
let f = c_try!(instance.inner.exports.get_function("_start"));
let start = c_try!(instance.inner.exports.get_function("_start"));
Some(Box::new(wasm_func_t {
inner: f.clone(),
inner: start.clone(),
instance: Some(instance.inner.clone()),
}))
}