Closes #274: Adding FFI function for types bool, float, String, vecbytes

.github/workflows/ValidatePullRequest.yml

@@ -65,7 +65,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
     - name: Spell Check Repo
-      uses: crate-ci/[email protected].2
+      uses: crate-ci/[email protected].3
 
   license-headers:
     name: check license headers

src/hyperlight_common/Cargo.toml

@@ -15,7 +15,7 @@ Hyperlight's components common to host and guest.
 workspace = true
 
 [dependencies]
-flatbuffers = { version = "25.2.10", default-features = false }
+flatbuffers = { version = "25.9.23", default-features = false }
 anyhow = { version = "1.0.100", default-features = false }
 log = "0.4.28"
 tracing = { version = "0.1.41", optional = true }

src/hyperlight_guest/Cargo.toml

@@ -16,7 +16,7 @@ anyhow = { version = "1.0.100", default-features = false }
 serde_json = { version = "1.0", default-features = false, features = ["alloc"] }
 hyperlight-common = { workspace = true }
 hyperlight-guest-tracing = { workspace = true, default-features = false }
-flatbuffers = { version= "25.2.10", default-features = false }
+flatbuffers = { version= "25.9.23", default-features = false }
 
 [features]
 default = []

src/hyperlight_guest_capi/src/flatbuffer.rs

@@ -15,6 +15,9 @@ limitations under the License.
 */
 
 use alloc::boxed::Box;
+use alloc::ffi::CString;
+use alloc::string::String;
+use alloc::vec::Vec;
 use core::ffi::{CStr, c_char};
 
 use hyperlight_common::flatbuffer_wrappers::util::get_flatbuffer_result;
@@ -115,4 +118,34 @@ pub extern "C" fn hl_get_host_return_value_as_ULong() -> u64 {
     get_host_return_value().expect("Unable to get host return value as ulong")
 }
 
-// TODO add bool, float, double, string, vecbytes
+#[unsafe(no_mangle)]
+pub extern "C" fn hl_get_host_return_value_as_Bool() -> bool {
+    get_host_return_value().expect("Unable to get host return value as bool")
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn hl_get_host_return_value_as_float() -> f32 {
+    get_host_return_value().expect("Unable to get host return value as f32")
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn hl_get_host_return_value_as_double() -> f64 {
+    get_host_return_value().expect("Unable to get host return value as f32")
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn hl_get_host_return_value_as_String() -> *const c_char {
+    let string_value: String =
+        get_host_return_value().expect("Unable to get host return value as string");
+
+    let c_string = CString::new(string_value).expect("Failed to create CString");
+    c_string.into_raw()
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn hl_get_host_return_value_as_VecBytes() -> Box<FfiVec> {
+    let vec_value: Vec<u8> =
+        get_host_return_value().expect("Unable to get host return value as vec bytes");
+
+    Box::new(unsafe { FfiVec::from_vec(vec_value) })
+}

src/hyperlight_host/Cargo.toml

@@ -26,8 +26,8 @@ gdbstub_arch = { version = "0.3.2", optional = true }
 goblin = { version = "0.10", default-features = false, features = ["std", "elf32", "elf64", "endian_fd"] }
 rand = { version = "0.9" }
 cfg-if = { version = "1.0.3" }
-libc = { version = "0.2.175" }
-flatbuffers = "25.2.10"
+libc = { version = "0.2.176" }
+flatbuffers = "25.9.23"
 framehop = { version = "0.15.0", optional = true }
 fallible-iterator = { version = "0.3.0", optional = true }
 blake3 = "1.8.2"
@@ -87,7 +87,7 @@ signal-hook-registry = "1.4.6"
 envy = { version = "0.4.2" }
 serde = "1.0"
 proptest = "1.8.0"
-tempfile = "3.22.0"
+tempfile = "3.23.0"
 crossbeam-queue = "0.3.12"
 tracing-serde = "0.2.0"
 hyperlight-testing = { workspace = true }
@@ -98,7 +98,7 @@ tracing-subscriber = {version = "0.3.20", features = ["std", "env-filter"]}
 tracing-opentelemetry = "0.31.0"
 opentelemetry = "0.30.0"
 opentelemetry-otlp = { version = "0.30.0", default-features = false, features = ["http-proto", "reqwest-blocking-client"] }
-opentelemetry-semantic-conventions = "0.30"
+opentelemetry-semantic-conventions = "0.31"
 opentelemetry_sdk = { version = "0.30.0", features = ["rt-tokio"] }
 tokio = { version = "1.47.1", features = ["full"] }
 criterion = "0.7.0"

src/hyperlight_host/tests/integration_test.rs

@@ -765,3 +765,14 @@ fn log_test_messages(levelfilter: Option<log::LevelFilter>) {
             .unwrap();
     }
 }
+
+// cargo test --test integration_test log_message -- --ignored
+#[test]
+fn test_if_guest_is_able_to_get_return_values_from_host() {
+    let mut sbox1 = new_uninit().unwrap().evolve().unwrap();
+
+
+    let res = sbox1.call::<()>("HostReturnsBoolValue", iterations).unwrap_err();
+    println!("{:?}", res);
+    assert!(matches!(res, HyperlightError::StackOverflow()));
+}

src/tests/c_guests/c_simpleguest/main.c

@@ -256,6 +256,24 @@ int guest_function(const char *from_host) {
   return 0;
 }
 
+
+bool host_returns_bool_value(const char *from_host) {
+  char guest_message[256] = "Hello from host_returns_bool_value, ";
+  int len = strlen(from_host);
+  strncat(guest_message, from_host, len);
+
+  hl_Parameter params = {.tag = hl_ParameterType_Bool,
+                         .value = {.Bool = true}};
+  const hl_FunctionCall host_call = {.function_name = "HostMethod1",
+                                     .parameters = &params,
+                                     .parameters_len = 1,
+                                     .return_type = hl_ReturnType_Bool
+                                    };
+  hl_call_host_function(&host_call);                                 
+  return hl_get_host_return_value_as_Bool();
+}
+
+HYPERLIGHT_WRAP_FUNCTION(host_returns_bool_value, Bool, 1, String)
 HYPERLIGHT_WRAP_FUNCTION(echo, String, 1, String)
 // HYPERLIGHT_WRAP_FUNCTION(set_byte_array_to_zero, 1, VecBytes) is not valid for functions that return VecBytes
 HYPERLIGHT_WRAP_FUNCTION(guest_function, Int, 1, String)
@@ -289,6 +307,7 @@ HYPERLIGHT_WRAP_FUNCTION(log_message, Int, 2, String, Long)
 
 void hyperlight_main(void)
 {
+    HYPERLIGHT_REGISTER_FUNCTION("HostReturnsBoolValue", host_returns_bool_value);
     HYPERLIGHT_REGISTER_FUNCTION("Echo", echo);
     // HYPERLIGHT_REGISTER_FUNCTION macro does not work for functions that return VecBytes,
     // so we use hl_register_function_definition directly
@@ -325,6 +344,9 @@ void hyperlight_main(void)
     // HYPERLIGHT_REGISTER_FUNCTION macro does not work for functions that return VecBytes,
     // so we use hl_register_function_definition directly
     hl_register_function_definition("24K_in_8K_out", twenty_four_k_in_eight_k_out, 1, (hl_ParameterType[]){hl_ParameterType_VecBytes}, hl_ReturnType_VecBytes);
+    // HYPERLIGHT_REGISTER_FUNCTION macro does not work for functions that return VecBytes,
+    // so we use hl_register_function_definition directly
+    hl_register_function_definition("24K_in_8K_out", twenty_four_k_in_eight_k_out, 1, (hl_ParameterType[]){hl_ParameterType_VecBytes}, hl_ReturnType_VecBytes);
 }
 
 // This dispatch function is only used when the host dispatches a guest function