Merge pull request #202 from wasmerio/feature/emscripten-getcwd

add getcwd syscall and create a test

lib/emscripten/emtests/test_getcwd.c

@@ -0,0 +1,10 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main() {
+    const unsigned int size = 256;
+    char cwd[size] = {};
+    char* buf = getcwd(cwd, size);
+    printf("getcwd\n");
+    return 0;
+}

lib/emscripten/emtests/test_getcwd.out

@@ -0,0 +1 @@
+getcwd

lib/emscripten/src/lib.rs

@@ -502,6 +502,7 @@ pub fn generate_emscripten_env(globals: &mut EmscriptenGlobals) -> ImportObject
             "___syscall168" => func!(crate::syscalls::___syscall168),
             "___syscall180" => func!(crate::syscalls::___syscall180),
             "___syscall181" => func!(crate::syscalls::___syscall181),
+            "___syscall183" => func!(crate::syscalls::___syscall183),
             "___syscall191" => func!(crate::syscalls::___syscall191),
             "___syscall192" => func!(crate::syscalls::___syscall192),
             "___syscall194" => func!(crate::syscalls::___syscall194),

lib/emscripten/src/syscalls/mod.rs

@@ -46,8 +46,13 @@ use std::slice;
 // Another conditional constant for name resolution: Macos et iOS use
 // SO_NOSIGPIPE as a setsockopt flag to disable SIGPIPE emission on socket.
 // Other platforms do otherwise.
+use crate::env::get_emscripten_data;
+use crate::utils::copy_cstr_into_wasm;
+use crate::utils::read_string_from_wasm;
 #[cfg(target_os = "darwin")]
 use libc::SO_NOSIGPIPE;
+use std::ffi::CString;
+
 #[cfg(not(target_os = "darwin"))]
 const SO_NOSIGPIPE: c_int = 0;
 
@@ -186,6 +191,25 @@ pub fn ___syscall110(_ctx: &mut Ctx, _one: i32, _two: i32) -> i32 {
     -1
 }
 
+// getcwd
+pub fn ___syscall183(ctx: &mut Ctx, buf_offset: u32, _size: u32) -> u32 {
+    debug!("emscripten::___syscall183");
+    use std::env;
+    let path = env::current_dir();
+    let path_string = path.unwrap().display().to_string();
+    let len = path_string.len();
+    unsafe {
+        let pointer_to_buffer =
+            emscripten_memory_pointer!(ctx.memory(0), buf_offset) as *mut libc::c_char;
+        let slice = slice::from_raw_parts_mut(pointer_to_buffer, len.clone());
+        for (byte, loc) in path_string.bytes().zip(slice.iter_mut()) {
+            *loc = byte as _;
+        }
+        *pointer_to_buffer.add(len.clone()) = 0;
+    }
+    buf_offset
+}
+
 // mmap2
 pub fn ___syscall192(ctx: &mut Ctx, which: c_int, mut varargs: VarArgs) -> c_int {
     debug!("emscripten::___syscall192 (mmap2) {}", which);

lib/emscripten/tests/emtests/mod.rs

@@ -54,6 +54,7 @@ mod test_funcptrfunc;
 mod test_funcs;
 mod test_functionpointer_libfunc_varargs;
 mod test_fwrite_0;
+mod test_getcwd;
 mod test_getgep;
 mod test_getloadavg;
 mod test_getopt;

lib/emscripten/tests/emtests/test_getcwd.rs

@@ -0,0 +1,9 @@
+#[test]
+fn test_getcwd() {
+    assert_emscripten_output!(
+        "../../emtests/test_getcwd.wasm",
+        "getcwd",
+        vec![],
+        "../../emtests/test_getcwd.out"
+    );
+}