From ca98aea664621def68dfb38e2269412b7dfd8ca3 Mon Sep 17 00:00:00 2001 From: Jake Lang Date: Wed, 13 Mar 2019 11:16:47 -0400 Subject: [PATCH] rust: Add helpers for execution result handling --- .codespell-whitelist | 1 + bindings/rust/evmc-vm/src/lib.rs | 192 ++++++++++++++++++++++++++++++- 2 files changed, 192 insertions(+), 1 deletion(-) diff --git a/.codespell-whitelist b/.codespell-whitelist index 0aa9bbca2..ddc16b0ef 100644 --- a/.codespell-whitelist +++ b/.codespell-whitelist @@ -1 +1,2 @@ iff +mut diff --git a/bindings/rust/evmc-vm/src/lib.rs b/bindings/rust/evmc-vm/src/lib.rs index 37a7e1f8a..c15865bee 100644 --- a/bindings/rust/evmc-vm/src/lib.rs +++ b/bindings/rust/evmc-vm/src/lib.rs @@ -2,6 +2,196 @@ pub extern crate evmc_sys; pub use evmc_sys as ffi; // TODO: Add helpers for host interface -// TODO: Add convenient helpers for evmc_result // TODO: Add convenient helpers for evmc_execute // TODO: Add a derive macro here for creating evmc_create + +/// EVMC result structure. +pub struct ExecutionResult { + status_code: ffi::evmc_status_code, + gas_left: i64, + output: Option>, + create_address: ffi::evmc_address, +} + +impl ExecutionResult { + pub fn new( + _status_code: ffi::evmc_status_code, + _gas_left: i64, + _output: Option>, + _create_address: ffi::evmc_address, + ) -> Self { + ExecutionResult { + status_code: _status_code, + gas_left: _gas_left, + output: _output, + create_address: _create_address, + } + } + + pub fn get_status_code(&self) -> ffi::evmc_status_code { + self.status_code + } + + pub fn get_gas_left(&self) -> i64 { + self.gas_left + } + + pub fn get_output(&self) -> Option<&Vec> { + self.output.as_ref() + } + + pub fn get_create_address(&self) -> Option<&ffi::evmc_address> { + // Only return Some if the address is valid (e.g. the status is EVMC_SUCCESS) + if self.status_code == ffi::evmc_status_code::EVMC_SUCCESS { + Some(&self.create_address) + } else { + None + } + } +} + +impl From for ExecutionResult { + fn from(result: ffi::evmc_result) -> Self { + let ret = ExecutionResult { + status_code: result.status_code, + gas_left: result.gas_left, + output: if !result.output_data.is_null() { + // Pre-allocate a vector. + let mut buf: Vec = Vec::with_capacity(result.output_size); + + unsafe { + // Set the len of the vec manually. + buf.set_len(result.output_size); + // Copy from the C struct's buffer to the vec's buffer. + std::ptr::copy(result.output_data, buf.as_mut_ptr(), result.output_size); + } + + Some(buf) + } else { + None + }, + create_address: result.create_address, + }; + + // Release allocated ffi struct. + unsafe { + if result.release.is_some() { + result.release.unwrap()(&result as *const ffi::evmc_result); + } + } + + ret + } +} + +/// Returns a pointer to a heap-allocated evmc_result. +impl Into<*const ffi::evmc_result> for ExecutionResult { + fn into(self) -> *const ffi::evmc_result { + let (buffer, len) = if let Some(buf) = self.output { + let buf_len = buf.len(); + + // Manually allocate heap memory for the new home of the output buffer. + let memlayout = std::alloc::Layout::from_size_align(buf_len, 1).expect("Bad layout"); + let new_buf = unsafe { std::alloc::alloc(memlayout) }; + unsafe { + // Copy the data into the allocated buffer. + std::ptr::copy(buf.as_ptr(), new_buf, buf_len); + } + + (new_buf as *const u8, buf_len) + } else { + (std::ptr::null(), 0) + }; + + Box::into_raw(Box::new(ffi::evmc_result { + status_code: self.status_code, + gas_left: self.gas_left, + output_data: buffer, + output_size: len, + release: Some(release_result), + create_address: self.create_address, + padding: [0u8; 4], + })) + } +} + +/// Callback to pass across FFI, de-allocating the struct. +extern "C" fn release_result(result: *const ffi::evmc_result) { + unsafe { + let tmp = Box::from_raw(result as *mut ffi::evmc_result); + if tmp.output_data.is_null() { + let buf_layout = + std::alloc::Layout::from_size_align(tmp.output_size, 1).expect("Bad layout"); + std::alloc::dealloc(tmp.output_data as *mut u8, buf_layout); + } + Box::from_raw(result as *mut ffi::evmc_result); + } +} + +#[cfg(test)] +mod tests { + use super::*; + use evmc_sys as ffi; + + #[test] + fn new_result() { + let r = ExecutionResult::new( + ffi::evmc_status_code::EVMC_FAILURE, + 420, + None, + ffi::evmc_address { bytes: [0u8; 20] }, + ); + + assert!(r.get_status_code() == ffi::evmc_status_code::EVMC_FAILURE); + assert!(r.get_gas_left() == 420); + assert!(r.get_output().is_none()); + + // Ensure that an address is not returned if it is not valid, per status code. + assert!(r.get_create_address().is_none()); + } + + #[test] + fn from_ffi() { + let f = ffi::evmc_result { + status_code: ffi::evmc_status_code::EVMC_SUCCESS, + gas_left: 1337, + output_data: Box::into_raw(Box::new([0xde, 0xad, 0xbe, 0xef])) as *const u8, + output_size: 4, + release: None, + create_address: ffi::evmc_address { bytes: [0u8; 20] }, + padding: [0u8; 4], + }; + + let r: ExecutionResult = f.into(); + + assert!(r.get_status_code() == ffi::evmc_status_code::EVMC_SUCCESS); + assert!(r.get_gas_left() == 1337); + assert!(r.get_output().is_some()); + assert!(r.get_output().unwrap().len() == 4); + assert!(r.get_create_address().is_some()); + } + + #[test] + fn into_ffi() { + let r = ExecutionResult::new( + ffi::evmc_status_code::EVMC_FAILURE, + 420, + Some(vec![0xc0, 0xff, 0xee, 0x71, 0x75]), + ffi::evmc_address { bytes: [0u8; 20] }, + ); + + let f: *const ffi::evmc_result = r.into(); + assert!(!f.is_null()); + unsafe { + assert!((*f).status_code == ffi::evmc_status_code::EVMC_FAILURE); + assert!((*f).gas_left == 420); + assert!(!(*f).output_data.is_null()); + assert!((*f).output_size == 5); + assert!( + std::slice::from_raw_parts((*f).output_data, 5) as &[u8] + == &[0xc0, 0xff, 0xee, 0x71, 0x75] + ); + assert!((*f).create_address.bytes == [0u8; 20]); + } + } +}