wasmer/src/apis/emscripten/utils.rs
2018-12-06 22:44:16 -05:00

122 lines
4.3 KiB
Rust

use byteorder::{ByteOrder, LittleEndian};
use crate::webassembly::module::Module;
use crate::webassembly::Instance;
use libc::stat;
use std::ffi::{CStr, CString};
use std::os::raw::c_char;
use std::slice;
use std::mem::size_of;
/// We check if a provided module is an Emscripten generated one
pub fn is_emscripten_module(module: &Module) -> bool {
for (module, field) in &module.info.imported_funcs {
if field == "_emscripten_memcpy_big" && module == "env" {
return true;
}
}
return false;
}
pub unsafe fn copy_cstr_into_wasm(instance: &mut Instance, cstr: *const c_char) -> u32 {
let s = CStr::from_ptr(cstr).to_str().unwrap();
let cstr_len = s.len();
let space_offset = (instance.emscripten_data.as_ref().unwrap().malloc)((cstr_len as i32) + 1, instance);
let raw_memory = instance.memory_offset_addr(0, space_offset as _) as *mut u8;
let slice = slice::from_raw_parts_mut(raw_memory, cstr_len);
for (byte, loc) in s.bytes().zip(slice.iter_mut()) {
*loc = byte;
}
*raw_memory.add(cstr_len) = 0;
space_offset
}
pub unsafe fn allocate_on_stack<'a, T: Copy>(count: u32, instance: &'a Instance) -> (u32, &'a mut [T]) {
let offset = (instance.emscripten_data.as_ref().unwrap().stack_alloc)(count * (size_of::<T>() as u32), instance);
let addr = instance.memory_offset_addr(0, offset as _) as *mut T;
let slice = slice::from_raw_parts_mut(addr, count as usize);
(offset, slice)
}
pub unsafe fn allocate_cstr_on_stack<'a>(s: &str, instance: &'a Instance) -> (u32, &'a [u8]) {
let (offset, slice) = allocate_on_stack((s.len() + 1) as u32, instance);
use std::iter;
for (byte, loc) in s.bytes().chain(iter::once(0)).zip(slice.iter_mut()) {
*loc = byte;
}
(offset, slice)
}
pub unsafe fn copy_terminated_array_of_cstrs(
_instance: &mut Instance,
cstrs: *mut *mut c_char,
) -> u32 {
let total_num = {
let mut ptr = cstrs;
let mut counter = 0;
while !(*ptr).is_null() {
counter += 1;
ptr = ptr.add(1);
}
counter
};
debug!(
"emscripten::copy_terminated_array_of_cstrs::total_num: {}",
total_num
);
0
}
pub unsafe fn copy_stat_into_wasm(instance: &mut Instance, buf: u32, stat: &stat) {
let buf_ptr = instance.memory_offset_addr(0, buf as _) as *mut u8;
let buf = slice::from_raw_parts_mut(buf_ptr, 76);
LittleEndian::write_u32(&mut buf[..], stat.st_dev as _);
LittleEndian::write_u32(&mut buf[4..], 0);
LittleEndian::write_u32(&mut buf[8..], stat.st_ino as _);
LittleEndian::write_u32(&mut buf[12..], stat.st_mode as _);
LittleEndian::write_u32(&mut buf[16..], stat.st_nlink as _);
LittleEndian::write_u32(&mut buf[20..], stat.st_uid);
LittleEndian::write_u32(&mut buf[24..], stat.st_gid);
LittleEndian::write_u32(&mut buf[28..], stat.st_rdev as _);
LittleEndian::write_u32(&mut buf[32..], 0);
LittleEndian::write_u32(&mut buf[36..], stat.st_size as _);
LittleEndian::write_u32(&mut buf[40..], 4096);
LittleEndian::write_u32(&mut buf[44..], stat.st_blocks as _);
LittleEndian::write_u32(&mut buf[48..], stat.st_atime as _);
LittleEndian::write_u32(&mut buf[52..], 0);
LittleEndian::write_u32(&mut buf[56..], stat.st_mtime as _);
LittleEndian::write_u32(&mut buf[60..], 0);
LittleEndian::write_u32(&mut buf[64..], stat.st_ctime as _);
LittleEndian::write_u32(&mut buf[68..], 0);
LittleEndian::write_u32(&mut buf[72..], stat.st_ino as _);
}
#[cfg(test)]
mod tests {
use super::super::generate_emscripten_env;
use super::is_emscripten_module;
use crate::webassembly::instantiate;
#[test]
fn should_detect_emscripten_files() {
let wasm_bytes = include_wast2wasm_bytes!("tests/is_emscripten_true.wast");
let import_object = generate_emscripten_env();
let result_object = instantiate(wasm_bytes, import_object).expect("Not compiled properly");
assert!(is_emscripten_module(&result_object.module));
}
#[test]
fn should_detect_non_emscripten_files() {
let wasm_bytes = include_wast2wasm_bytes!("tests/is_emscripten_false.wast");
let import_object = generate_emscripten_env();
let result_object = instantiate(wasm_bytes, import_object).expect("Not compiled properly");
assert!(!is_emscripten_module(&result_object.module));
}
}