Merge #301

301: Add arg and env support to wasi r=lachlansneff a=lachlansneff



Co-authored-by: Lachlan Sneff <lachlan.sneff@gmail.com>

lib/wasi/src/lib.rs

@@ -1,14 +1,33 @@
+mod state;
 mod syscalls;
-use syscalls::*;
+use self::state::WasiState;
+use self::syscalls::*;
+
+use std::ffi::c_void;
 
 use wasmer_runtime_core::{func, import::ImportObject, imports};
 
-pub fn generate_import_object() -> ImportObject {
+pub fn generate_import_object(args: Vec<Vec<u8>>, envs: Vec<Vec<u8>>) -> ImportObject {
+    let state_gen = move || {
+        fn state_dtor(data: *mut c_void) {
+            unsafe {
+                drop(Box::from_raw(data as *mut WasiState));
+            }
+        }
+
+        let state = Box::new(WasiState {
+            args: &args[..],
+            envs: &envs[..],
+        });
+
+        (
+            Box::leak(state) as *mut WasiState as *mut c_void,
+            state_dtor as fn(*mut c_void),
+        )
+    };
     imports! {
         // This generates the wasi state.
-        || {
-            // returns (pointer to state, function that can destruct the state).
-        },
+        state_gen,
         "wasi_unstable" => {
             "__wasi_args_get" => func!(__wasi_args_get),
             "__wasi_args_sizes_get" => func!(__wasi_args_sizes_get),

lib/wasi/src/state.rs

@@ -0,0 +1,5 @@
+pub struct WasiState<'a> {
+    // vfs: Vfs,
+    pub args: &'a [Vec<u8>],
+    pub envs: &'a [Vec<u8>],
+}

lib/wasi/src/syscalls/mod.rs

@@ -1,23 +1,104 @@
-use wasmer_runtime_core::vm::Ctx;
+use crate::state::WasiState;
+use wasmer_runtime_core::{memory::Memory, vm::Ctx};
 
-pub fn __wasi_args_get(ctx: &mut Ctx) {
-    unimplemented!()
+#[allow(clippy::mut_from_ref)]
+fn get_wasi_state(ctx: &Ctx) -> &mut WasiState {
+    unsafe { &mut *(ctx.data as *mut WasiState) }
 }
-pub fn __wasi_args_sizes_get(ctx: &mut Ctx) {
-    unimplemented!()
+
+fn write_buffer_array(
+    memory: &Memory,
+    from: &[Vec<u8>],
+    ptr_buffer_offset: u32,
+    buffer_offset: u32,
+) {
+    let mut current_buffer_offset = buffer_offset;
+    for (i, sub_buffer) in from.iter().enumerate() {
+        memory.view::<u32>()[(ptr_buffer_offset as usize)..][i].set(current_buffer_offset);
+        for (cell, &byte) in memory.view()[(current_buffer_offset as usize)..]
+            .iter()
+            .zip(sub_buffer.iter())
+        {
+            cell.set(byte);
+        }
+        current_buffer_offset += sub_buffer.len() as u32;
+    }
+}
+
+/// ### `__wasi_args_get()`
+/// Read command-line argument data.
+/// The sizes of the buffers should match that returned by [`__wasi_args_sizes_get()`](#args_sizes_get).
+/// Inputs:
+/// - `char **argv`
+///     A pointer to a buffer to write the argument pointers.
+/// - `char *argv_buf`
+///     A pointer to a buffer to write the argument string data.
+///
+pub fn __wasi_args_get(ctx: &mut Ctx, ptr_buffer_offset: u32, buffer_offset: u32) {
+    let state = get_wasi_state(ctx);
+    let memory = ctx.memory(0);
+
+    write_buffer_array(memory, &*state.args, ptr_buffer_offset, buffer_offset);
+}
+
+/// ### `__wasi_args_sizes_get()`
+/// Return command-line argument data sizes.
+/// Outputs:
+/// - `size_t *argc`
+///     The number of arguments.
+/// - `size_t *argv_buf_size`
+///     The size of the argument string data.
+pub fn __wasi_args_sizes_get(ctx: &mut Ctx, argc_out: u32, argv_buf_size_out: u32) {
+    let state = get_wasi_state(ctx);
+    let memory = ctx.memory(0);
+
+    let arg_count = state.args.len();
+    let total_arg_size: usize = state.args.iter().map(|v| v.len()).sum();
+
+    memory.view::<u32>()[(argc_out / 4) as usize].set(arg_count as u32);
+    memory.view::<u32>()[(argv_buf_size_out / 4) as usize].set(total_arg_size as u32);
 }
+
 pub fn __wasi_clock_res_get(ctx: &mut Ctx) {
     unimplemented!()
 }
 pub fn __wasi_clock_time_get(ctx: &mut Ctx) {
     unimplemented!()
 }
-pub fn __wasi_environ_get(ctx: &mut Ctx) {
-    unimplemented!()
+
+/// ### `__wasi_environ_get()`
+/// Read environment variable data.
+/// The sizes of the buffers should match that returned by [`__wasi_environ_sizes_get()`](#environ_sizes_get).
+/// Inputs:
+/// - `char **environ`
+///     A pointer to a buffer to write the environment variable pointers.
+/// - `char *environ_buf`
+///     A pointer to a buffer to write the environment variable string data.
+pub fn __wasi_environ_get(ctx: &mut Ctx, environ: u32, environ_buf: u32) {
+    let state = get_wasi_state(ctx);
+    let memory = ctx.memory(0);
+
+    write_buffer_array(memory, &*state.args, environ, environ_buf);
 }
-pub fn __wasi_environ_sizes_get(ctx: &mut Ctx) {
-    unimplemented!()
+
+/// ### `__wasi_environ_sizes_get()`
+/// Return command-line argument data sizes.
+/// Outputs:
+/// - `size_t *environ_count`
+///     The number of environment variables.
+/// - `size_t *environ_buf_size`
+///     The size of the environment variable string data.
+pub fn __wasi_environ_sizes_get(ctx: &mut Ctx, environ_count_out: u32, environ_buf_size_out: u32) {
+    let state = get_wasi_state(ctx);
+    let memory = ctx.memory(0);
+
+    let env_count = state.envs.len();
+    let total_env_size: usize = state.envs.iter().map(|v| v.len()).sum();
+
+    memory.view::<u32>()[(environ_count_out / 4) as usize].set(env_count as u32);
+    memory.view::<u32>()[(environ_buf_size_out / 4) as usize].set(total_env_size as u32);
 }
+
 pub fn __wasi_fd_advise(ctx: &mut Ctx) {
     unimplemented!()
 }