Support for the WASI ABI.

lib/wasi/Cargo.toml

@@ -5,4 +5,6 @@ authors = ["The Wasmer Engineering Team <engineering@wasmer.io>"]
 edition = "2018"
 
 [dependencies]
-wasmer-runtime-core = { path = "../runtime-core", version = "0.2.1" }
+wasmer-runtime-core = { path = "../runtime-core", version = "0.2.1" }
+libc = "0.2.50"
+rand = "0.6.5"

lib/wasi/src/syscalls/mod.rs

@@ -1,14 +1,24 @@
 #![allow(unused)]
-
-mod types;
+pub mod types;
+#[cfg(any(target_os = "linux", target_os = "macos"))]
+pub mod unix;
+#[cfg(any(target_os = "windows"))]
+pub mod windows;
 
 use self::types::*;
 use crate::{
     ptr::{Array, WasmPtr},
     state::WasiState,
 };
+use rand::{thread_rng, Rng};
 use wasmer_runtime_core::{memory::Memory, vm::Ctx};
 
+#[cfg(any(target_os = "linux", target_os = "macos"))]
+pub use unix::*;
+
+#[cfg(any(target_os = "windows"))]
+pub use windows::*;
+
 #[allow(clippy::mut_from_ref)]
 fn get_wasi_state(ctx: &Ctx) -> &mut WasiState {
     unsafe { &mut *(ctx.data as *mut WasiState) }
@@ -99,15 +109,28 @@ pub fn clock_res_get(
     clock_id: __wasi_clockid_t,
     resolution: WasmPtr<__wasi_timestamp_t>,
 ) -> __wasi_errno_t {
-    unimplemented!()
+    let memory = ctx.memory(0);
+
+    if let Some(out_addr) = resolution.deref(memory) {
+        platform_clock_res_get(clock_id, out_addr)
+    } else {
+        __WASI_EFAULT
+    }
 }
+
 pub fn clock_time_get(
     ctx: &mut Ctx,
     clock_id: __wasi_clockid_t,
     precision: __wasi_timestamp_t,
     time: WasmPtr<__wasi_timestamp_t>,
 ) -> __wasi_errno_t {
-    unimplemented!()
+    let memory = ctx.memory(0);
+
+    if let Some(out_addr) = time.deref(memory) {
+        platform_clock_time_get(clock_id, precision, out_addr)
+    } else {
+        __WASI_EFAULT
+    }
 }
 
 /// ### `environ_get()`
@@ -225,6 +248,7 @@ pub fn fd_filestat_set_times(
 ) -> __wasi_errno_t {
     unimplemented!()
 }
+
 pub fn fd_pread(
     ctx: &mut Ctx,
     fd: __wasi_fd_t,
@@ -233,8 +257,17 @@ pub fn fd_pread(
     offset: __wasi_filesize_t,
     nread: WasmPtr<u32>,
 ) -> __wasi_errno_t {
-    unimplemented!()
+    let memory = ctx.memory(0);
+
+    if let ((Some(iov_cells), Some(nread_cell))) =
+        (iovs.deref(memory, 0, iovs_len), nread.deref(memory))
+    {
+        platform_fd_pread(fd, iov_cells, iovs_len, offset, nread_cell)
+    } else {
+        __WASI_EFAULT
+    }
 }
+
 pub fn fd_prestat_get(
     ctx: &mut Ctx,
     fd: __wasi_fd_t,
@@ -452,12 +485,36 @@ pub fn proc_exit(ctx: &mut Ctx, rval: __wasi_exitcode_t) {
 pub fn proc_raise(ctx: &mut Ctx, sig: __wasi_signal_t) -> __wasi_errno_t {
     unimplemented!()
 }
+
+/// ### `random_get()`
+/// Fill buffer with high-quality random data.  This function may be slow and block
+/// Inputs:
+/// - `void *buf`
+///     A pointer to a buffer where the random bytes will be written
+/// - `size_t buf_len`
+///     The number of bytes that will be written
 pub fn random_get(ctx: &mut Ctx, buf: WasmPtr<u8, Array>, buf_len: u32) -> __wasi_errno_t {
-    unimplemented!()
+    let mut rng = thread_rng();
+    let memory = ctx.memory(0);
+
+    if let Some(buf) = buf.deref(memory, 0, buf_len) {
+        for i in 0..(buf_len as usize) {
+            let random_byte = rng.gen::<u8>();
+            buf[i].set(random_byte);
+        }
+    } else {
+        return __WASI_EFAULT;
+    }
+
+    __WASI_ESUCCESS
 }
+
+/// ### `sched_yield()`
+/// Yields execution of the thread
 pub fn sched_yield(ctx: &mut Ctx) -> __wasi_errno_t {
-    unimplemented!()
+    __WASI_ESUCCESS
 }
+
 pub fn sock_recv(
     ctx: &mut Ctx,
     sock: __wasi_fd_t,

lib/wasi/src/syscalls/types.rs

@@ -333,6 +333,25 @@ pub struct __wasi_iovec_t {
     pub buf_len: u32,
 }
 
+impl ValueType for __wasi_iovec_t {
+    fn into_le(self, buffer: &mut [u8]) {
+        self.buf
+            .into_le(&mut buffer[..mem::size_of::<WasmPtr<u8, Array>>()]);
+        self.buf_len
+            .into_le(&mut buffer[mem::size_of::<WasmPtr<u8, Array>>()..]);
+    }
+
+    fn from_le(buffer: &[u8]) -> Result<Self, ValueError> {
+        if buffer.len() >= mem::size_of::<__wasi_iovec_t>() {
+            let buf = ValueType::from_le(&buffer[..mem::size_of::<WasmPtr<u8, Array>>()])?;
+            let buf_len = ValueType::from_le(&buffer[mem::size_of::<WasmPtr<u8, Array>>()..])?;
+            Ok(Self { buf, buf_len })
+        } else {
+            Err(ValueError::BufferTooSmall)
+        }
+    }
+}
+
 pub type __wasi_linkcount_t = u32;
 
 pub type __wasi_lookupflags_t = u32;

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

@@ -0,0 +1,36 @@
+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

@@ -0,0 +1,12 @@
+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

@@ -0,0 +1,71 @@
+#[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,
+    CLOCK_REALTIME, CLOCK_THREAD_CPUTIME_ID,
+};
+use std::cell::Cell;
+use std::mem;
+
+pub fn platform_clock_res_get(
+    clock_id: __wasi_clockid_t,
+    resolution: &Cell<__wasi_timestamp_t>,
+) -> __wasi_errno_t {
+    let unix_clock_id = match clock_id {
+        __WASI_CLOCK_MONOTONIC => CLOCK_MONOTONIC,
+        __WASI_CLOCK_PROCESS_CPUTIME_ID => CLOCK_PROCESS_CPUTIME_ID,
+        __WASI_CLOCK_REALTIME => CLOCK_REALTIME,
+        __WASI_CLOCK_THREAD_CPUTIME_ID => CLOCK_THREAD_CPUTIME_ID,
+        _ => return __WASI_EINVAL,
+    };
+
+    let (output, timespec_out) = unsafe {
+        let mut timespec_out: timespec = mem::uninitialized();
+        (clock_getres(unix_clock_id, &mut timespec_out), timespec_out)
+    };
+
+    resolution.set(timespec_out.tv_nsec as __wasi_timestamp_t);
+
+    // TODO: map output of clock_getres to __wasi_errno_t
+    __WASI_ESUCCESS
+}
+
+pub fn platform_clock_time_get(
+    clock_id: __wasi_clockid_t,
+    precision: __wasi_timestamp_t,
+    time: &Cell<__wasi_timestamp_t>,
+) -> __wasi_errno_t {
+    let unix_clock_id = match clock_id {
+        __WASI_CLOCK_MONOTONIC => CLOCK_MONOTONIC,
+        __WASI_CLOCK_PROCESS_CPUTIME_ID => CLOCK_PROCESS_CPUTIME_ID,
+        __WASI_CLOCK_REALTIME => CLOCK_REALTIME,
+        __WASI_CLOCK_THREAD_CPUTIME_ID => CLOCK_THREAD_CPUTIME_ID,
+        _ => return __WASI_EINVAL,
+    };
+
+    let (output, timespec_out) = unsafe {
+        let mut timespec_out: timespec = mem::uninitialized();
+        (
+            clock_gettime(unix_clock_id, &mut timespec_out),
+            timespec_out,
+        )
+    };
+
+    // TODO: adjust output by precision...
+
+    time.set(timespec_out.tv_nsec as __wasi_timestamp_t);
+
+    // TODO: map output of clock_gettime to __wasi_errno_t
+    __WASI_ESUCCESS
+}

lib/wasi/src/syscalls/windows.rs

@@ -0,0 +1,27 @@
+use crate::syscalls::types::*;
+use std::cell::Cell;
+
+pub fn platform_clock_res_get(
+    clock_id: __wasi_clockid_t,
+    resolution: &Cell<__wasi_timestamp_t>,
+) -> __wasi_errno_t {
+    __WASI_EINVAL
+}
+
+pub fn platform_clock_time_get(
+    clock_id: __wasi_clockid_t,
+    precision: __wasi_timestamp_t,
+    time: &Cell<__wasi_timestamp_t>,
+) -> __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!()
+}