From 485da4c7019e0d101cce90e16f634966bf981b93 Mon Sep 17 00:00:00 2001
From: Steve Akinyemi <appcypher@outlook.com>
Date: Fri, 7 Dec 2018 04:08:17 +0100
Subject: [PATCH] More debugging

---
 src/apis/emscripten/mod.rs   |  2 +-
 src/apis/emscripten/utils.rs | 22 +++++++++++++++++++---
 src/apis/mod.rs              |  2 +-
 src/bin/wasmer.rs            |  8 ++++----
 4 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/src/apis/emscripten/mod.rs b/src/apis/emscripten/mod.rs
index 22d71a581..81620df1b 100644
--- a/src/apis/emscripten/mod.rs
+++ b/src/apis/emscripten/mod.rs
@@ -19,7 +19,7 @@ mod utils;
 mod varargs;
 
 pub use self::storage::{align_memory, static_alloc};
-pub use self::utils::{is_emscripten_module, copy_cstr_array_into_wasm};
+pub use self::utils::{is_emscripten_module, copy_cstr_array_into_wasm_stack};
 
 // TODO: Magic number - how is this calculated?
 const TOTAL_STACK: u32 = 5242880;
diff --git a/src/apis/emscripten/utils.rs b/src/apis/emscripten/utils.rs
index 4418ec264..4f13c3f61 100644
--- a/src/apis/emscripten/utils.rs
+++ b/src/apis/emscripten/utils.rs
@@ -18,6 +18,22 @@ pub fn is_emscripten_module(module: &Module) -> bool {
 }
 
 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 _, 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 copy_cstr_into_wasm_stack(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().stack_alloc)((cstr_len as u32) + 1, instance);
@@ -33,8 +49,8 @@ pub unsafe fn copy_cstr_into_wasm(instance: &mut Instance, cstr: *const c_char)
     space_offset
 }
 
-pub unsafe fn copy_cstr_array_into_wasm(array_count: u32, array: *mut *mut c_char, instance: &mut Instance) -> u32 {
-    let array_offset = (instance.emscripten_data.as_ref().unwrap().stack_alloc)((array_count as usize * size_of::<u32>()) as _, instance);
+pub unsafe fn copy_cstr_array_into_wasm_stack(array_count: u32, array: *mut *mut c_char, instance: &mut Instance) -> u32 {
+    let array_offset = (instance.emscripten_data.as_ref().unwrap().stack_alloc)(((array_count as usize + 1) * size_of::<u32>()) as _, instance);
     let array_addr = instance.memory_offset_addr(0, array_offset as _) as *mut u32;
     let array_slice = slice::from_raw_parts_mut(array_addr, array_count as usize);
 
@@ -45,7 +61,7 @@ pub unsafe fn copy_cstr_array_into_wasm(array_count: u32, array: *mut *mut c_cha
 
     // println!("###### x = {:?}", *array_addr.add(array_count as usize));
 
-    // *array_addr.add(array_count as usize) = 0;
+    *array_addr.add(array_count as usize) = 0;
 
     // let arg_addr = instance.memory_offset_addr(0, *array_addr.offset(0) as _) as *const i8;
     // debug!("###### argv[0] = {:?}", CStr::from_ptr(arg_addr));
diff --git a/src/apis/mod.rs b/src/apis/mod.rs
index 588b2fc1f..ad236483e 100644
--- a/src/apis/mod.rs
+++ b/src/apis/mod.rs
@@ -1,4 +1,4 @@
 pub mod emscripten;
 pub mod host;
 
-pub use self::emscripten::{align_memory, generate_emscripten_env, is_emscripten_module, copy_cstr_array_into_wasm};
+pub use self::emscripten::{align_memory, generate_emscripten_env, is_emscripten_module, copy_cstr_array_into_wasm_stack};
diff --git a/src/bin/wasmer.rs b/src/bin/wasmer.rs
index 344078544..932cdd37c 100644
--- a/src/bin/wasmer.rs
+++ b/src/bin/wasmer.rs
@@ -7,7 +7,7 @@ use std::io::Read;
 use std::path::PathBuf;
 use std::process::exit;
 
-use apis::emscripten::copy_cstr_array_into_wasm;
+use apis::emscripten::copy_cstr_array_into_wasm_stack;
 use structopt::StructOpt;
 
 use wasmer::*;
@@ -88,12 +88,12 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
             _ => panic!("_main emscripten function not found"),
         };
 
-        let main: extern "C" fn(u32, u32, u32, &webassembly::Instance) =
+        let main: extern "C" fn(u32, u32, &webassembly::Instance) =
             get_instance_function!(instance, func_index);
 
         let (argc, argv) = get_module_arguments(options, &mut instance);
 
-        return call_protected!(main(argc, argv, 0, &instance)).map_err(|err| format!("{}", err));
+        return call_protected!(main(argc, argv, &instance)).map_err(|err| format!("{}", err));
         // TODO: We should implement emscripten __ATEXIT__
     } else {
         let func_index =
@@ -153,7 +153,7 @@ fn get_module_arguments(options: &Run, instance: &mut webassembly::Instance) ->
 
     // Copy the the arguments into the wasm memory and get offset
     let argv_offset =  unsafe {
-        copy_cstr_array_into_wasm(argc, argv, instance)
+        copy_cstr_array_into_wasm_stack(argc, argv, instance)
     };
 
     debug!("argc = {:?}", argc);