add mapdir for emscripten; implement getdents, etc.

CHANGELOG.md

@@ -6,6 +6,7 @@ Blocks of changes will separated by version increments.
 
 ## **[Unreleased]**
 
+- [#470](https://github.com/wasmerio/wasmer/pull/470) Add mapdir support to Emscripten, implement getdents for Unix
 - [#467](https://github.com/wasmerio/wasmer/pull/467) `wasmer_instantiate` returns better error messages in the runtime C API
 - [#463](https://github.com/wasmerio/wasmer/pull/463) Fix bug in WASI path_open allowing one level above preopened dir to be accessed
 - [#461](https://github.com/wasmerio/wasmer/pull/461) Prevent passing negative lengths in various places in the runtime C API

lib/emscripten/Cargo.toml

@@ -9,14 +9,15 @@ edition = "2018"
 build = "build/mod.rs"
 
 [dependencies]
-wasmer-runtime-core = { path = "../runtime-core", version = "0.4.2" }
+byteorder = "1"
+hashbrown = "0.1"
 lazy_static = "1.2.0"
 libc = "0.2.49"
-byteorder = "1"
 time = "0.1.41"
 wasmer-clif-backend = { path = "../clif-backend", version = "0.4.2" }
-wasmer-singlepass-backend = { path = "../singlepass-backend", version = "0.4.2", optional = true }
 wasmer-llvm-backend = { path = "../llvm-backend", version = "0.4.2", optional = true }
+wasmer-runtime-core = { path = "../runtime-core", version = "0.4.2" }
+wasmer-singlepass-backend = { path = "../singlepass-backend", version = "0.4.2", optional = true }
 
 [target.'cfg(windows)'.dependencies]
 rand = "0.6"

lib/emscripten/src/lib.rs

@@ -3,8 +3,10 @@
 #[macro_use]
 extern crate wasmer_runtime_core;
 
+use hashbrown::HashMap;
 use lazy_static::lazy_static;
 use std::cell::UnsafeCell;
+use std::path::PathBuf;
 use std::{f64, ffi::c_void};
 use wasmer_runtime_core::{
     error::CallResult,
@@ -141,10 +143,14 @@ pub struct EmscriptenData<'a> {
     pub stack_save: Option<Func<'a, (), i32>>,
     pub stack_restore: Option<Func<'a, (i32)>>,
     pub set_threw: Option<Func<'a, (i32, i32)>>,
+    pub mapped_dirs: HashMap<String, PathBuf>,
 }
 
 impl<'a> EmscriptenData<'a> {
-    pub fn new(instance: &'a mut Instance) -> EmscriptenData<'a> {
+    pub fn new(
+        instance: &'a mut Instance,
+        mapped_dirs: HashMap<String, PathBuf>,
+    ) -> EmscriptenData<'a> {
         let malloc = instance.func("_malloc").unwrap();
         let free = instance.func("_free").unwrap();
         let memalign = instance.func("_memalign").ok();
@@ -272,6 +278,7 @@ impl<'a> EmscriptenData<'a> {
             stack_save,
             stack_restore,
             set_threw,
+            mapped_dirs,
         }
     }
 }
@@ -282,8 +289,9 @@ pub fn run_emscripten_instance(
     path: &str,
     args: Vec<&str>,
     entrypoint: Option<String>,
+    mapped_dirs: Vec<(String, PathBuf)>,
 ) -> CallResult<()> {
-    let mut data = EmscriptenData::new(instance);
+    let mut data = EmscriptenData::new(instance, mapped_dirs.into_iter().collect());
     let data_ptr = &mut data as *mut _ as *mut c_void;
     instance.context_mut().data = data_ptr;
 

lib/emscripten/src/syscalls/mod.rs

@@ -10,7 +10,8 @@ pub use self::unix::*;
 #[cfg(windows)]
 pub use self::windows::*;
 
-use super::utils::copy_stat_into_wasm;
+use crate::utils::{copy_stat_into_wasm, get_cstr_path, get_current_directory};
+
 use super::varargs::VarArgs;
 use byteorder::{ByteOrder, LittleEndian};
 /// NOTE: TODO: These syscalls only support wasm_32 for now because they assume offsets are u32
@@ -95,12 +96,19 @@ pub fn ___syscall6(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> c_int
 pub fn ___syscall12(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> c_int {
     debug!("emscripten::___syscall12 (chdir) {}", _which);
     let path_ptr = varargs.get_str(ctx);
-    unsafe {
-        let _path = std::ffi::CStr::from_ptr(path_ptr);
-        let ret = chdir(path_ptr);
-        debug!("=> path: {:?}, ret: {}", _path, ret);
+    let real_path_owned = get_cstr_path(ctx, path_ptr);
+    let real_path = if let Some(ref rp) = real_path_owned {
+        rp.as_c_str().as_ptr()
+    } else {
+        path_ptr
+    };
+    let ret = unsafe { chdir(real_path) };
+    debug!(
+        "=> path: {:?}, ret: {}",
+        unsafe { std::ffi::CStr::from_ptr(real_path) },
         ret
-    }
+    );
+    ret
 }
 
 pub fn ___syscall10(_ctx: &mut Ctx, _one: i32, _two: i32) -> i32 {
@@ -124,11 +132,23 @@ pub fn ___syscall38(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> i32 {
     debug!("emscripten::___syscall38 (rename)");
     let old_path = varargs.get_str(ctx);
     let new_path = varargs.get_str(ctx);
-    let result = unsafe { rename(old_path, new_path) };
+    let real_old_path_owned = get_cstr_path(ctx, old_path);
+    let real_old_path = if let Some(ref rp) = real_old_path_owned {
+        rp.as_c_str().as_ptr()
+    } else {
+        old_path
+    };
+    let real_new_path_owned = get_cstr_path(ctx, new_path);
+    let real_new_path = if let Some(ref rp) = real_new_path_owned {
+        rp.as_c_str().as_ptr()
+    } else {
+        new_path
+    };
+    let result = unsafe { rename(real_old_path, real_new_path) };
     debug!(
         "=> old_path: {}, new_path: {}, result: {}",
-        unsafe { std::ffi::CStr::from_ptr(old_path).to_str().unwrap() },
-        unsafe { std::ffi::CStr::from_ptr(new_path).to_str().unwrap() },
+        unsafe { std::ffi::CStr::from_ptr(real_old_path).to_str().unwrap() },
+        unsafe { std::ffi::CStr::from_ptr(real_new_path).to_str().unwrap() },
         result
     );
     result
@@ -138,7 +158,13 @@ pub fn ___syscall38(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> i32 {
 pub fn ___syscall40(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> c_int {
     debug!("emscripten::___syscall40 (rmdir)");
     let pathname_addr = varargs.get_str(ctx);
-    unsafe { rmdir(pathname_addr) }
+    let real_path_owned = get_cstr_path(ctx, pathname_addr);
+    let real_path = if let Some(ref rp) = real_path_owned {
+        rp.as_c_str().as_ptr()
+    } else {
+        pathname_addr
+    };
+    unsafe { rmdir(real_path) }
 }
 
 // pipe
@@ -244,10 +270,9 @@ pub fn ___syscall110(_ctx: &mut Ctx, _one: i32, _two: i32) -> i32 {
 // getcwd
 pub fn ___syscall183(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> i32 {
     debug!("emscripten::___syscall183");
-    use std::env;
     let buf_offset: c_int = varargs.get(ctx);
     let _size: c_int = varargs.get(ctx);
-    let path = env::current_dir();
+    let path = get_current_directory(ctx);
     let path_string = path.unwrap().display().to_string();
     let len = path_string.len();
     unsafe {
@@ -420,12 +445,19 @@ pub fn ___syscall195(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> c_in
     let pathname_addr = varargs.get_str(ctx);
     let buf: u32 = varargs.get(ctx);
 
+    let real_path_owned = get_cstr_path(ctx, pathname_addr);
+    let real_path = if let Some(ref rp) = real_path_owned {
+        rp.as_c_str().as_ptr()
+    } else {
+        pathname_addr
+    };
+
     unsafe {
         let mut _stat: stat = std::mem::zeroed();
-        let ret = stat(pathname_addr, &mut _stat);
+        let ret = stat(real_path, &mut _stat);
         debug!(
             "=> pathname: {}, buf: {} = {}, last os error: {}",
-            std::ffi::CStr::from_ptr(pathname_addr).to_str().unwrap(),
+            std::ffi::CStr::from_ptr(real_path).to_str().unwrap(),
             buf,
             ret,
             Error::last_os_error()
@@ -457,11 +489,6 @@ pub fn ___syscall197(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> c_in
     0
 }
 
-pub fn ___syscall220(_ctx: &mut Ctx, _one: i32, _two: i32) -> i32 {
-    debug!("emscripten::___syscall220");
-    -1
-}
-
 // fcntl64
 pub fn ___syscall221(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> c_int {
     debug!("emscripten::___syscall221 (fcntl64) {}", _which);
@@ -474,7 +501,7 @@ pub fn ___syscall221(ctx: &mut Ctx, _which: c_int, mut varargs: VarArgs) -> c_in
     // |FNONBLOCK - 0x04
     debug!("=> fd: {}, cmd: {}", _fd, cmd);
     match cmd {
-        2 => 0,
+        1 | 2 => 0,
         13 | 14 => 0, // pretend file locking worked
         _ => -1,
     }