clean up platform-specific syscall code

lib/wasi/src/syscalls/mod.rs

@@ -489,13 +489,12 @@ pub fn fd_pread(
     debug!("wasi::fd_pread");
     let memory = ctx.memory(0);
 
-    if let ((Ok(iov_cells), Ok(nread_cell))) =
+    let iov_cells = wasi_try!(iovs.deref(memory, 0, iovs_len));
-        (iovs.deref(memory, 0, iovs_len), nread.deref(memory))
+    let nread_cell = wasi_try!(nread.deref(memory));
-    {
+
-        platform_fd_pread(fd, iov_cells, iovs_len, offset, nread_cell)
+    unimplemented!();
-    } else {
+
-        __WASI_EFAULT
+    __WASI_ESUCCESS
-    }
 }
 
 /// ### `fd_prestat_get()`

lib/wasi/src/syscalls/unix/linux.rs

@@ -1,36 +0,0 @@
-use crate::syscalls::types::*;
-use std::cell::Cell;
-use std::mem;
-
-use libc::preadv;
-
-pub fn platform_fd_pread(
-    fd: __wasi_fd_t,
-    iovs: &[Cell<__wasi_iovec_t>],
-    iovs_len: u32,
-    offset: __wasi_filesize_t,
-    nread: &Cell<u32>,
-) -> __wasi_errno_t {
-    let (result, iovec) = unsafe {
-        let mut iovec = vec![mem::uninitialized(); iovs_len as usize];
-        (
-            preadv(
-                fd as i32,
-                iovec.as_mut_ptr(),
-                iovs_len as i32,
-                offset as i64,
-            ),
-            iovec,
-        )
-    };
-    nread.set(result as u32);
-    /*for (i, arr_cell) in iovs.iter().enumerate() {
-        let wasi_iovec = __wasi_iovec_t {
-            buf: iovec[i] as _,
-            buf_len: iovec[i].iov_len as u32,
-        };
-        arr_cell.set(wasi_iovec);
-    }*/
-
-    __WASI_ESUCCESS
-}

lib/wasi/src/syscalls/unix/macos.rs

@@ -1,12 +0,0 @@
-use crate::syscalls::types::*;
-use std::cell::Cell;
-
-pub fn platform_fd_pread(
-    fd: __wasi_fd_t,
-    iovs: &[Cell<__wasi_iovec_t>],
-    iovs_len: u32,
-    offset: __wasi_filesize_t,
-    nread: &Cell<u32>,
-) -> __wasi_errno_t {
-    unimplemented!()
-}

lib/wasi/src/syscalls/unix/mod.rs

@@ -1,15 +1,3 @@
-#[cfg(target_os = "linux")]
-pub mod linux;
-
-#[cfg(target_os = "macos")]
-pub mod macos;
-
-#[cfg(target_os = "linux")]
-pub use linux::*;
-
-#[cfg(target_os = "macos")]
-pub use macos::*;
-
 use crate::syscalls::types::*;
 use libc::{
     clock_getres, clock_gettime, timespec, CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID,

lib/wasi/src/syscalls/windows.rs

@@ -15,13 +15,3 @@ pub fn platform_clock_time_get(
 ) -> __wasi_errno_t {
     unimplemented!()
 }
-
-pub fn platform_fd_pread(
-    fd: __wasi_fd_t,
-    iovs: &[Cell<__wasi_iovec_t>],
-    iovs_len: u32,
-    offset: __wasi_filesize_t,
-    nread: &Cell<u32>,
-) -> __wasi_errno_t {
-    unimplemented!()
-}