Isolated emscripten in new lib

lib/emscripten/src/process.rs

@@ -0,0 +1,69 @@
+use libc::{abort, c_char, c_int, exit, pid_t, EAGAIN};
+
+use wasmer_runtime::Instance;
+use std::ffi::CStr;
+
+pub extern "C" fn abort_with_message(message: &str) {
+    debug!("emscripten::abort_with_message");
+    println!("{}", message);
+    _abort();
+}
+
+pub extern "C" fn _abort() {
+    debug!("emscripten::_abort");
+    unsafe {
+        abort();
+    }
+}
+
+pub extern "C" fn _fork(_instance: &mut Instance) -> pid_t {
+    debug!("emscripten::_fork");
+    // unsafe {
+    //     fork()
+    // }
+    -1
+}
+
+pub extern "C" fn _exit(status: c_int, _instance: &mut Instance) -> ! {
+    debug!("emscripten::_exit {}", status);
+    unsafe { exit(status) }
+}
+
+pub extern "C" fn em_abort(message: u32, instance: &mut Instance) {
+    debug!("emscripten::em_abort {}", message);
+    let message_addr = instance.memory_offset_addr(0, message as usize) as *mut c_char;
+    unsafe {
+        let message = CStr::from_ptr(message_addr)
+            .to_str()
+            .unwrap_or("Unexpected abort");
+
+        abort_with_message(message);
+    }
+}
+
+pub extern "C" fn abort_stack_overflow() {
+    debug!("emscripten::abort_stack_overflow");
+    // TODO: Message incomplete. Need to finish em runtime data first
+    abort_with_message("Stack overflow! Attempted to allocate some bytes on the stack");
+}
+
+pub extern "C" fn _llvm_trap() {
+    debug!("emscripten::_llvm_trap");
+    abort_with_message("abort!");
+}
+
+pub extern "C" fn _system() -> c_int {
+    debug!("emscripten::_system");
+    // TODO: May need to change this Em impl to a working version
+    eprintln!("Can't call external programs");
+    return EAGAIN;
+}
+
+pub extern "C" fn _popen() -> c_int {
+    debug!("emscripten::_popen");
+    // TODO: May need to change this Em impl to a working version
+    eprintln!("Missing function: popen");
+    unsafe {
+        abort();
+    }
+}