Add some syscalls

src/linkers/emscripten/README.md

@@ -150,7 +150,7 @@
 ```
 - <a name="exit"></a>exit - _[__syscall1](#__syscall1)_ &nbsp;&nbsp;&nbsp;&nbsp;[:top:](#emscripten-syscalls)
 ```rust
-fn exit(error_code: usize)
+fn exit(status: c_int)
 ```
 - <a name="faccessat"></a>faccessat - _[__syscall307](#__syscall307)_ &nbsp;&nbsp;&nbsp;&nbsp;[:top:](#emscripten-syscalls)
 ```rust
@@ -289,7 +289,7 @@ fn exit(error_code: usize)
 ```
 - <a name="open"></a>open - _[__syscall5](#__syscall5)_ &nbsp;&nbsp;&nbsp;&nbsp;[:top:](#emscripten-syscalls)
 ```rust
-fn open(pathname: *const char, flags: usize, mode: usize) -> usize
+fn open(path: *const c_char, oflag: c_int, ...) -> c_int 
 ```
 - <a name="openat"></a>openat - _[__syscall295](#__syscall295)_ &nbsp;&nbsp;&nbsp;&nbsp;[:top:](#emscripten-syscalls)
 ```rust

src/linkers/emscripten/mod.rs

@@ -3,6 +3,7 @@ use crate::webassembly::{ImportObject, ImportValue};
 mod abort;
 mod printf;
 mod putchar;
+mod syscalls;
 
 pub fn generate_emscripten_env<'a, 'b>() -> ImportObject<&'a str, &'b str> {
     let mut import_object = ImportObject::new();
@@ -10,6 +11,10 @@ pub fn generate_emscripten_env<'a, 'b>() -> ImportObject<&'a str, &'b str> {
     import_object.set("env", "putchar", ImportValue::Func(putchar::putchar as *const u8));
     import_object.set("env", "abort", ImportValue::Func(abort::abort as *const u8));
     import_object.set("env", "_abort", ImportValue::Func(abort::abort as *const u8));
+    // SYSCALLS
+    import_object.set("env", "__syscall1", ImportValue::Func(syscalls::__syscall1 as *const u8));
+    import_object.set("env", "__syscall3", ImportValue::Func(syscalls::__syscall3 as *const u8));
+    import_object.set("env", "__syscall5", ImportValue::Func(syscalls::__syscall5 as *const u8));
     import_object
 }
 

src/linkers/emscripten/syscalls/darwin/mod.rs

@@ -0,0 +1 @@
+pub mod syscalls;

src/linkers/emscripten/syscalls/darwin/syscalls.rs

@@ -0,0 +1,25 @@
+use libc::{
+    c_int,
+    c_void,
+    c_char,
+    size_t,
+    ssize_t,
+    open,
+    exit,
+    read,
+};
+
+/// exit
+pub extern "C" fn __syscall1(status: c_int) {
+    unsafe { exit(status); }
+}
+
+/// read
+pub extern "C" fn __syscall3(fd: c_int, buf: *mut c_void, count: size_t) -> ssize_t {
+    unsafe { read(fd, buf, count) }
+}
+
+/// open
+pub extern "C" fn __syscall5(path: *const c_char, oflag: c_int) -> c_int {
+    unsafe { open(path, oflag) }
+}

src/linkers/emscripten/syscalls/mod.rs

@@ -0,0 +1,3 @@
+mod darwin;
+
+pub use self::darwin::syscalls::*;